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| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
|---|---|---|
| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
| commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
| tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /Documentation/networking | |
| parent | Initial commit. (diff) | |
| download | linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip | |
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'Documentation/networking')
247 files changed, 65953 insertions, 0 deletions
diff --git a/Documentation/networking/6lowpan.rst b/Documentation/networking/6lowpan.rst new file mode 100644 index 0000000000..e70a6520cc --- /dev/null +++ b/Documentation/networking/6lowpan.rst @@ -0,0 +1,53 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================================== +Netdev private dataroom for 6lowpan interfaces +============================================== + +All 6lowpan able net devices, means all interfaces with ARPHRD_6LOWPAN, +must have "struct lowpan_priv" placed at beginning of netdev_priv. + +The priv_size of each interface should be calculate by:: + + dev->priv_size = LOWPAN_PRIV_SIZE(LL_6LOWPAN_PRIV_DATA); + +Where LL_PRIV_6LOWPAN_DATA is sizeof linklayer 6lowpan private data struct. +To access the LL_PRIV_6LOWPAN_DATA structure you can cast:: + + lowpan_priv(dev)-priv; + +to your LL_6LOWPAN_PRIV_DATA structure. + +Before registering the lowpan netdev interface you must run:: + + lowpan_netdev_setup(dev, LOWPAN_LLTYPE_FOOBAR); + +wheres LOWPAN_LLTYPE_FOOBAR is a define for your 6LoWPAN linklayer type of +enum lowpan_lltypes. + +Example to evaluate the private usually you can do:: + + static inline struct lowpan_priv_foobar * + lowpan_foobar_priv(struct net_device *dev) + { + return (struct lowpan_priv_foobar *)lowpan_priv(dev)->priv; + } + + switch (dev->type) { + case ARPHRD_6LOWPAN: + lowpan_priv = lowpan_priv(dev); + /* do great stuff which is ARPHRD_6LOWPAN related */ + switch (lowpan_priv->lltype) { + case LOWPAN_LLTYPE_FOOBAR: + /* do 802.15.4 6LoWPAN handling here */ + lowpan_foobar_priv(dev)->bar = foo; + break; + ... + } + break; + ... + } + +In case of generic 6lowpan branch ("net/6lowpan") you can remove the check +on ARPHRD_6LOWPAN, because you can be sure that these function are called +by ARPHRD_6LOWPAN interfaces. diff --git a/Documentation/networking/6pack.rst b/Documentation/networking/6pack.rst new file mode 100644 index 0000000000..bc5bf1f1a9 --- /dev/null +++ b/Documentation/networking/6pack.rst @@ -0,0 +1,191 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============== +6pack Protocol +============== + +This is the 6pack-mini-HOWTO, written by + +Andreas Könsgen DG3KQ + +:Internet: ajk@comnets.uni-bremen.de +:AMPR-net: dg3kq@db0pra.ampr.org +:AX.25: dg3kq@db0ach.#nrw.deu.eu + +Last update: April 7, 1998 + +1. What is 6pack, and what are the advantages to KISS? +====================================================== + +6pack is a transmission protocol for data exchange between the PC and +the TNC over a serial line. It can be used as an alternative to KISS. + +6pack has two major advantages: + +- The PC is given full control over the radio + channel. Special control data is exchanged between the PC and the TNC so + that the PC knows at any time if the TNC is receiving data, if a TNC + buffer underrun or overrun has occurred, if the PTT is + set and so on. This control data is processed at a higher priority than + normal data, so a data stream can be interrupted at any time to issue an + important event. This helps to improve the channel access and timing + algorithms as everything is computed in the PC. It would even be possible + to experiment with something completely different from the known CSMA and + DAMA channel access methods. + This kind of real-time control is especially important to supply several + TNCs that are connected between each other and the PC by a daisy chain + (however, this feature is not supported yet by the Linux 6pack driver). + +- Each packet transferred over the serial line is supplied with a checksum, + so it is easy to detect errors due to problems on the serial line. + Received packets that are corrupt are not passed on to the AX.25 layer. + Damaged packets that the TNC has received from the PC are not transmitted. + +More details about 6pack are described in the file 6pack.ps that is located +in the doc directory of the AX.25 utilities package. + +2. Who has developed the 6pack protocol? +======================================== + +The 6pack protocol has been developed by Ekki Plicht DF4OR, Henning Rech +DF9IC and Gunter Jost DK7WJ. A driver for 6pack, written by Gunter Jost and +Matthias Welwarsky DG2FEF, comes along with the PC version of FlexNet. +They have also written a firmware for TNCs to perform the 6pack +protocol (see section 4 below). + +3. Where can I get the latest version of 6pack for LinuX? +========================================================= + +At the moment, the 6pack stuff can obtained via anonymous ftp from +db0bm.automation.fh-aachen.de. In the directory /incoming/dg3kq, +there is a file named 6pack.tgz. + +4. Preparing the TNC for 6pack operation +======================================== + +To be able to use 6pack, a special firmware for the TNC is needed. The EPROM +of a newly bought TNC does not contain 6pack, so you will have to +program an EPROM yourself. The image file for 6pack EPROMs should be +available on any packet radio box where PC/FlexNet can be found. The name of +the file is 6pack.bin. This file is copyrighted and maintained by the FlexNet +team. It can be used under the terms of the license that comes along +with PC/FlexNet. Please do not ask me about the internals of this file as I +don't know anything about it. I used a textual description of the 6pack +protocol to program the Linux driver. + +TNCs contain a 64kByte EPROM, the lower half of which is used for +the firmware/KISS. The upper half is either empty or is sometimes +programmed with software called TAPR. In the latter case, the TNC +is supplied with a DIP switch so you can easily change between the +two systems. When programming a new EPROM, one of the systems is replaced +by 6pack. It is useful to replace TAPR, as this software is rarely used +nowadays. If your TNC is not equipped with the switch mentioned above, you +can build in one yourself that switches over the highest address pin +of the EPROM between HIGH and LOW level. After having inserted the new EPROM +and switched to 6pack, apply power to the TNC for a first test. The connect +and the status LED are lit for about a second if the firmware initialises +the TNC correctly. + +5. Building and installing the 6pack driver +=========================================== + +The driver has been tested with kernel version 2.1.90. Use with older +kernels may lead to a compilation error because the interface to a kernel +function has been changed in the 2.1.8x kernels. + +How to turn on 6pack support: +============================= + +- In the linux kernel configuration program, select the code maturity level + options menu and turn on the prompting for development drivers. + +- Select the amateur radio support menu and turn on the serial port 6pack + driver. + +- Compile and install the kernel and the modules. + +To use the driver, the kissattach program delivered with the AX.25 utilities +has to be modified. + +- Do a cd to the directory that holds the kissattach sources. Edit the + kissattach.c file. At the top, insert the following lines:: + + #ifndef N_6PACK + #define N_6PACK (N_AX25+1) + #endif + + Then find the line: + + int disc = N_AX25; + + and replace N_AX25 by N_6PACK. + +- Recompile kissattach. Rename it to spattach to avoid confusions. + +Installing the driver: +---------------------- + +- Do an insmod 6pack. Look at your /var/log/messages file to check if the + module has printed its initialization message. + +- Do a spattach as you would launch kissattach when starting a KISS port. + Check if the kernel prints the message '6pack: TNC found'. + +- From here, everything should work as if you were setting up a KISS port. + The only difference is that the network device that represents + the 6pack port is called sp instead of sl or ax. So, sp0 would be the + first 6pack port. + +Although the driver has been tested on various platforms, I still declare it +ALPHA. BE CAREFUL! Sync your disks before insmoding the 6pack module +and spattaching. Watch out if your computer behaves strangely. Read section +6 of this file about known problems. + +Note that the connect and status LEDs of the TNC are controlled in a +different way than they are when the TNC is used with PC/FlexNet. When using +FlexNet, the connect LED is on if there is a connection; the status LED is +on if there is data in the buffer of the PC's AX.25 engine that has to be +transmitted. Under Linux, the 6pack layer is beyond the AX.25 layer, +so the 6pack driver doesn't know anything about connects or data that +has not yet been transmitted. Therefore the LEDs are controlled +as they are in KISS mode: The connect LED is turned on if data is transferred +from the PC to the TNC over the serial line, the status LED if data is +sent to the PC. + +6. Known problems +================= + +When testing the driver with 2.0.3x kernels and +operating with data rates on the radio channel of 9600 Baud or higher, +the driver may, on certain systems, sometimes print the message '6pack: +bad checksum', which is due to data loss if the other station sends two +or more subsequent packets. I have been told that this is due to a problem +with the serial driver of 2.0.3x kernels. I don't know yet if the problem +still exists with 2.1.x kernels, as I have heard that the serial driver +code has been changed with 2.1.x. + +When shutting down the sp interface with ifconfig, the kernel crashes if +there is still an AX.25 connection left over which an IP connection was +running, even if that IP connection is already closed. The problem does not +occur when there is a bare AX.25 connection still running. I don't know if +this is a problem of the 6pack driver or something else in the kernel. + +The driver has been tested as a module, not yet as a kernel-builtin driver. + +The 6pack protocol supports daisy-chaining of TNCs in a token ring, which is +connected to one serial port of the PC. This feature is not implemented +and at least at the moment I won't be able to do it because I do not have +the opportunity to build a TNC daisy-chain and test it. + +Some of the comments in the source code are inaccurate. They are left from +the SLIP/KISS driver, from which the 6pack driver has been derived. +I haven't modified or removed them yet -- sorry! The code itself needs +some cleaning and optimizing. This will be done in a later release. + +If you encounter a bug or if you have a question or suggestion concerning the +driver, feel free to mail me, using the addresses given at the beginning of +this file. + +Have fun! + +Andreas diff --git a/Documentation/networking/af_xdp.rst b/Documentation/networking/af_xdp.rst new file mode 100644 index 0000000000..dceeb0d763 --- /dev/null +++ b/Documentation/networking/af_xdp.rst @@ -0,0 +1,849 @@ +.. SPDX-License-Identifier: GPL-2.0 + +====== +AF_XDP +====== + +Overview +======== + +AF_XDP is an address family that is optimized for high performance +packet processing. + +This document assumes that the reader is familiar with BPF and XDP. If +not, the Cilium project has an excellent reference guide at +http://cilium.readthedocs.io/en/latest/bpf/. + +Using the XDP_REDIRECT action from an XDP program, the program can +redirect ingress frames to other XDP enabled netdevs, using the +bpf_redirect_map() function. AF_XDP sockets enable the possibility for +XDP programs to redirect frames to a memory buffer in a user-space +application. + +An AF_XDP socket (XSK) is created with the normal socket() +syscall. Associated with each XSK are two rings: the RX ring and the +TX ring. A socket can receive packets on the RX ring and it can send +packets on the TX ring. These rings are registered and sized with the +setsockopts XDP_RX_RING and XDP_TX_RING, respectively. It is mandatory +to have at least one of these rings for each socket. An RX or TX +descriptor ring points to a data buffer in a memory area called a +UMEM. RX and TX can share the same UMEM so that a packet does not have +to be copied between RX and TX. Moreover, if a packet needs to be kept +for a while due to a possible retransmit, the descriptor that points +to that packet can be changed to point to another and reused right +away. This again avoids copying data. + +The UMEM consists of a number of equally sized chunks. A descriptor in +one of the rings references a frame by referencing its addr. The addr +is simply an offset within the entire UMEM region. The user space +allocates memory for this UMEM using whatever means it feels is most +appropriate (malloc, mmap, huge pages, etc). This memory area is then +registered with the kernel using the new setsockopt XDP_UMEM_REG. The +UMEM also has two rings: the FILL ring and the COMPLETION ring. The +FILL ring is used by the application to send down addr for the kernel +to fill in with RX packet data. References to these frames will then +appear in the RX ring once each packet has been received. The +COMPLETION ring, on the other hand, contains frame addr that the +kernel has transmitted completely and can now be used again by user +space, for either TX or RX. Thus, the frame addrs appearing in the +COMPLETION ring are addrs that were previously transmitted using the +TX ring. In summary, the RX and FILL rings are used for the RX path +and the TX and COMPLETION rings are used for the TX path. + +The socket is then finally bound with a bind() call to a device and a +specific queue id on that device, and it is not until bind is +completed that traffic starts to flow. + +The UMEM can be shared between processes, if desired. If a process +wants to do this, it simply skips the registration of the UMEM and its +corresponding two rings, sets the XDP_SHARED_UMEM flag in the bind +call and submits the XSK of the process it would like to share UMEM +with as well as its own newly created XSK socket. The new process will +then receive frame addr references in its own RX ring that point to +this shared UMEM. Note that since the ring structures are +single-consumer / single-producer (for performance reasons), the new +process has to create its own socket with associated RX and TX rings, +since it cannot share this with the other process. This is also the +reason that there is only one set of FILL and COMPLETION rings per +UMEM. It is the responsibility of a single process to handle the UMEM. + +How is then packets distributed from an XDP program to the XSKs? There +is a BPF map called XSKMAP (or BPF_MAP_TYPE_XSKMAP in full). The +user-space application can place an XSK at an arbitrary place in this +map. The XDP program can then redirect a packet to a specific index in +this map and at this point XDP validates that the XSK in that map was +indeed bound to that device and ring number. If not, the packet is +dropped. If the map is empty at that index, the packet is also +dropped. This also means that it is currently mandatory to have an XDP +program loaded (and one XSK in the XSKMAP) to be able to get any +traffic to user space through the XSK. + +AF_XDP can operate in two different modes: XDP_SKB and XDP_DRV. If the +driver does not have support for XDP, or XDP_SKB is explicitly chosen +when loading the XDP program, XDP_SKB mode is employed that uses SKBs +together with the generic XDP support and copies out the data to user +space. A fallback mode that works for any network device. On the other +hand, if the driver has support for XDP, it will be used by the AF_XDP +code to provide better performance, but there is still a copy of the +data into user space. + +Concepts +======== + +In order to use an AF_XDP socket, a number of associated objects need +to be setup. These objects and their options are explained in the +following sections. + +For an overview on how AF_XDP works, you can also take a look at the +Linux Plumbers paper from 2018 on the subject: +http://vger.kernel.org/lpc_net2018_talks/lpc18_paper_af_xdp_perf-v2.pdf. Do +NOT consult the paper from 2017 on "AF_PACKET v4", the first attempt +at AF_XDP. Nearly everything changed since then. Jonathan Corbet has +also written an excellent article on LWN, "Accelerating networking +with AF_XDP". It can be found at https://lwn.net/Articles/750845/. + +UMEM +---- + +UMEM is a region of virtual contiguous memory, divided into +equal-sized frames. An UMEM is associated to a netdev and a specific +queue id of that netdev. It is created and configured (chunk size, +headroom, start address and size) by using the XDP_UMEM_REG setsockopt +system call. A UMEM is bound to a netdev and queue id, via the bind() +system call. + +An AF_XDP is socket linked to a single UMEM, but one UMEM can have +multiple AF_XDP sockets. To share an UMEM created via one socket A, +the next socket B can do this by setting the XDP_SHARED_UMEM flag in +struct sockaddr_xdp member sxdp_flags, and passing the file descriptor +of A to struct sockaddr_xdp member sxdp_shared_umem_fd. + +The UMEM has two single-producer/single-consumer rings that are used +to transfer ownership of UMEM frames between the kernel and the +user-space application. + +Rings +----- + +There are a four different kind of rings: FILL, COMPLETION, RX and +TX. All rings are single-producer/single-consumer, so the user-space +application need explicit synchronization of multiple +processes/threads are reading/writing to them. + +The UMEM uses two rings: FILL and COMPLETION. Each socket associated +with the UMEM must have an RX queue, TX queue or both. Say, that there +is a setup with four sockets (all doing TX and RX). Then there will be +one FILL ring, one COMPLETION ring, four TX rings and four RX rings. + +The rings are head(producer)/tail(consumer) based rings. A producer +writes the data ring at the index pointed out by struct xdp_ring +producer member, and increasing the producer index. A consumer reads +the data ring at the index pointed out by struct xdp_ring consumer +member, and increasing the consumer index. + +The rings are configured and created via the _RING setsockopt system +calls and mmapped to user-space using the appropriate offset to mmap() +(XDP_PGOFF_RX_RING, XDP_PGOFF_TX_RING, XDP_UMEM_PGOFF_FILL_RING and +XDP_UMEM_PGOFF_COMPLETION_RING). + +The size of the rings need to be of size power of two. + +UMEM Fill Ring +~~~~~~~~~~~~~~ + +The FILL ring is used to transfer ownership of UMEM frames from +user-space to kernel-space. The UMEM addrs are passed in the ring. As +an example, if the UMEM is 64k and each chunk is 4k, then the UMEM has +16 chunks and can pass addrs between 0 and 64k. + +Frames passed to the kernel are used for the ingress path (RX rings). + +The user application produces UMEM addrs to this ring. Note that, if +running the application with aligned chunk mode, the kernel will mask +the incoming addr. E.g. for a chunk size of 2k, the log2(2048) LSB of +the addr will be masked off, meaning that 2048, 2050 and 3000 refers +to the same chunk. If the user application is run in the unaligned +chunks mode, then the incoming addr will be left untouched. + + +UMEM Completion Ring +~~~~~~~~~~~~~~~~~~~~ + +The COMPLETION Ring is used transfer ownership of UMEM frames from +kernel-space to user-space. Just like the FILL ring, UMEM indices are +used. + +Frames passed from the kernel to user-space are frames that has been +sent (TX ring) and can be used by user-space again. + +The user application consumes UMEM addrs from this ring. + + +RX Ring +~~~~~~~ + +The RX ring is the receiving side of a socket. Each entry in the ring +is a struct xdp_desc descriptor. The descriptor contains UMEM offset +(addr) and the length of the data (len). + +If no frames have been passed to kernel via the FILL ring, no +descriptors will (or can) appear on the RX ring. + +The user application consumes struct xdp_desc descriptors from this +ring. + +TX Ring +~~~~~~~ + +The TX ring is used to send frames. The struct xdp_desc descriptor is +filled (index, length and offset) and passed into the ring. + +To start the transfer a sendmsg() system call is required. This might +be relaxed in the future. + +The user application produces struct xdp_desc descriptors to this +ring. + +Libbpf +====== + +Libbpf is a helper library for eBPF and XDP that makes using these +technologies a lot simpler. It also contains specific helper functions +in tools/lib/bpf/xsk.h for facilitating the use of AF_XDP. It +contains two types of functions: those that can be used to make the +setup of AF_XDP socket easier and ones that can be used in the data +plane to access the rings safely and quickly. To see an example on how +to use this API, please take a look at the sample application in +samples/bpf/xdpsock_usr.c which uses libbpf for both setup and data +plane operations. + +We recommend that you use this library unless you have become a power +user. It will make your program a lot simpler. + +XSKMAP / BPF_MAP_TYPE_XSKMAP +============================ + +On XDP side there is a BPF map type BPF_MAP_TYPE_XSKMAP (XSKMAP) that +is used in conjunction with bpf_redirect_map() to pass the ingress +frame to a socket. + +The user application inserts the socket into the map, via the bpf() +system call. + +Note that if an XDP program tries to redirect to a socket that does +not match the queue configuration and netdev, the frame will be +dropped. E.g. an AF_XDP socket is bound to netdev eth0 and +queue 17. Only the XDP program executing for eth0 and queue 17 will +successfully pass data to the socket. Please refer to the sample +application (samples/bpf/) in for an example. + +Configuration Flags and Socket Options +====================================== + +These are the various configuration flags that can be used to control +and monitor the behavior of AF_XDP sockets. + +XDP_COPY and XDP_ZEROCOPY bind flags +------------------------------------ + +When you bind to a socket, the kernel will first try to use zero-copy +copy. If zero-copy is not supported, it will fall back on using copy +mode, i.e. copying all packets out to user space. But if you would +like to force a certain mode, you can use the following flags. If you +pass the XDP_COPY flag to the bind call, the kernel will force the +socket into copy mode. If it cannot use copy mode, the bind call will +fail with an error. Conversely, the XDP_ZEROCOPY flag will force the +socket into zero-copy mode or fail. + +XDP_SHARED_UMEM bind flag +------------------------- + +This flag enables you to bind multiple sockets to the same UMEM. It +works on the same queue id, between queue ids and between +netdevs/devices. In this mode, each socket has their own RX and TX +rings as usual, but you are going to have one or more FILL and +COMPLETION ring pairs. You have to create one of these pairs per +unique netdev and queue id tuple that you bind to. + +Starting with the case were we would like to share a UMEM between +sockets bound to the same netdev and queue id. The UMEM (tied to the +fist socket created) will only have a single FILL ring and a single +COMPLETION ring as there is only on unique netdev,queue_id tuple that +we have bound to. To use this mode, create the first socket and bind +it in the normal way. Create a second socket and create an RX and a TX +ring, or at least one of them, but no FILL or COMPLETION rings as the +ones from the first socket will be used. In the bind call, set he +XDP_SHARED_UMEM option and provide the initial socket's fd in the +sxdp_shared_umem_fd field. You can attach an arbitrary number of extra +sockets this way. + +What socket will then a packet arrive on? This is decided by the XDP +program. Put all the sockets in the XSK_MAP and just indicate which +index in the array you would like to send each packet to. A simple +round-robin example of distributing packets is shown below: + +.. code-block:: c + + #include <linux/bpf.h> + #include "bpf_helpers.h" + + #define MAX_SOCKS 16 + + struct { + __uint(type, BPF_MAP_TYPE_XSKMAP); + __uint(max_entries, MAX_SOCKS); + __uint(key_size, sizeof(int)); + __uint(value_size, sizeof(int)); + } xsks_map SEC(".maps"); + + static unsigned int rr; + + SEC("xdp_sock") int xdp_sock_prog(struct xdp_md *ctx) + { + rr = (rr + 1) & (MAX_SOCKS - 1); + + return bpf_redirect_map(&xsks_map, rr, XDP_DROP); + } + +Note, that since there is only a single set of FILL and COMPLETION +rings, and they are single producer, single consumer rings, you need +to make sure that multiple processes or threads do not use these rings +concurrently. There are no synchronization primitives in the +libbpf code that protects multiple users at this point in time. + +Libbpf uses this mode if you create more than one socket tied to the +same UMEM. However, note that you need to supply the +XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD libbpf_flag with the +xsk_socket__create calls and load your own XDP program as there is no +built in one in libbpf that will route the traffic for you. + +The second case is when you share a UMEM between sockets that are +bound to different queue ids and/or netdevs. In this case you have to +create one FILL ring and one COMPLETION ring for each unique +netdev,queue_id pair. Let us say you want to create two sockets bound +to two different queue ids on the same netdev. Create the first socket +and bind it in the normal way. Create a second socket and create an RX +and a TX ring, or at least one of them, and then one FILL and +COMPLETION ring for this socket. Then in the bind call, set he +XDP_SHARED_UMEM option and provide the initial socket's fd in the +sxdp_shared_umem_fd field as you registered the UMEM on that +socket. These two sockets will now share one and the same UMEM. + +There is no need to supply an XDP program like the one in the previous +case where sockets were bound to the same queue id and +device. Instead, use the NIC's packet steering capabilities to steer +the packets to the right queue. In the previous example, there is only +one queue shared among sockets, so the NIC cannot do this steering. It +can only steer between queues. + +In libbpf, you need to use the xsk_socket__create_shared() API as it +takes a reference to a FILL ring and a COMPLETION ring that will be +created for you and bound to the shared UMEM. You can use this +function for all the sockets you create, or you can use it for the +second and following ones and use xsk_socket__create() for the first +one. Both methods yield the same result. + +Note that a UMEM can be shared between sockets on the same queue id +and device, as well as between queues on the same device and between +devices at the same time. + +XDP_USE_NEED_WAKEUP bind flag +----------------------------- + +This option adds support for a new flag called need_wakeup that is +present in the FILL ring and the TX ring, the rings for which user +space is a producer. When this option is set in the bind call, the +need_wakeup flag will be set if the kernel needs to be explicitly +woken up by a syscall to continue processing packets. If the flag is +zero, no syscall is needed. + +If the flag is set on the FILL ring, the application needs to call +poll() to be able to continue to receive packets on the RX ring. This +can happen, for example, when the kernel has detected that there are no +more buffers on the FILL ring and no buffers left on the RX HW ring of +the NIC. In this case, interrupts are turned off as the NIC cannot +receive any packets (as there are no buffers to put them in), and the +need_wakeup flag is set so that user space can put buffers on the +FILL ring and then call poll() so that the kernel driver can put these +buffers on the HW ring and start to receive packets. + +If the flag is set for the TX ring, it means that the application +needs to explicitly notify the kernel to send any packets put on the +TX ring. This can be accomplished either by a poll() call, as in the +RX path, or by calling sendto(). + +An example of how to use this flag can be found in +samples/bpf/xdpsock_user.c. An example with the use of libbpf helpers +would look like this for the TX path: + +.. code-block:: c + + if (xsk_ring_prod__needs_wakeup(&my_tx_ring)) + sendto(xsk_socket__fd(xsk_handle), NULL, 0, MSG_DONTWAIT, NULL, 0); + +I.e., only use the syscall if the flag is set. + +We recommend that you always enable this mode as it usually leads to +better performance especially if you run the application and the +driver on the same core, but also if you use different cores for the +application and the kernel driver, as it reduces the number of +syscalls needed for the TX path. + +XDP_{RX|TX|UMEM_FILL|UMEM_COMPLETION}_RING setsockopts +------------------------------------------------------ + +These setsockopts sets the number of descriptors that the RX, TX, +FILL, and COMPLETION rings respectively should have. It is mandatory +to set the size of at least one of the RX and TX rings. If you set +both, you will be able to both receive and send traffic from your +application, but if you only want to do one of them, you can save +resources by only setting up one of them. Both the FILL ring and the +COMPLETION ring are mandatory as you need to have a UMEM tied to your +socket. But if the XDP_SHARED_UMEM flag is used, any socket after the +first one does not have a UMEM and should in that case not have any +FILL or COMPLETION rings created as the ones from the shared UMEM will +be used. Note, that the rings are single-producer single-consumer, so +do not try to access them from multiple processes at the same +time. See the XDP_SHARED_UMEM section. + +In libbpf, you can create Rx-only and Tx-only sockets by supplying +NULL to the rx and tx arguments, respectively, to the +xsk_socket__create function. + +If you create a Tx-only socket, we recommend that you do not put any +packets on the fill ring. If you do this, drivers might think you are +going to receive something when you in fact will not, and this can +negatively impact performance. + +XDP_UMEM_REG setsockopt +----------------------- + +This setsockopt registers a UMEM to a socket. This is the area that +contain all the buffers that packet can reside in. The call takes a +pointer to the beginning of this area and the size of it. Moreover, it +also has parameter called chunk_size that is the size that the UMEM is +divided into. It can only be 2K or 4K at the moment. If you have an +UMEM area that is 128K and a chunk size of 2K, this means that you +will be able to hold a maximum of 128K / 2K = 64 packets in your UMEM +area and that your largest packet size can be 2K. + +There is also an option to set the headroom of each single buffer in +the UMEM. If you set this to N bytes, it means that the packet will +start N bytes into the buffer leaving the first N bytes for the +application to use. The final option is the flags field, but it will +be dealt with in separate sections for each UMEM flag. + +SO_BINDTODEVICE setsockopt +-------------------------- + +This is a generic SOL_SOCKET option that can be used to tie AF_XDP +socket to a particular network interface. It is useful when a socket +is created by a privileged process and passed to a non-privileged one. +Once the option is set, kernel will refuse attempts to bind that socket +to a different interface. Updating the value requires CAP_NET_RAW. + +XDP_STATISTICS getsockopt +------------------------- + +Gets drop statistics of a socket that can be useful for debug +purposes. The supported statistics are shown below: + +.. code-block:: c + + struct xdp_statistics { + __u64 rx_dropped; /* Dropped for reasons other than invalid desc */ + __u64 rx_invalid_descs; /* Dropped due to invalid descriptor */ + __u64 tx_invalid_descs; /* Dropped due to invalid descriptor */ + }; + +XDP_OPTIONS getsockopt +---------------------- + +Gets options from an XDP socket. The only one supported so far is +XDP_OPTIONS_ZEROCOPY which tells you if zero-copy is on or not. + +Multi-Buffer Support +==================== + +With multi-buffer support, programs using AF_XDP sockets can receive +and transmit packets consisting of multiple buffers both in copy and +zero-copy mode. For example, a packet can consist of two +frames/buffers, one with the header and the other one with the data, +or a 9K Ethernet jumbo frame can be constructed by chaining together +three 4K frames. + +Some definitions: + +* A packet consists of one or more frames + +* A descriptor in one of the AF_XDP rings always refers to a single + frame. In the case the packet consists of a single frame, the + descriptor refers to the whole packet. + +To enable multi-buffer support for an AF_XDP socket, use the new bind +flag XDP_USE_SG. If this is not provided, all multi-buffer packets +will be dropped just as before. Note that the XDP program loaded also +needs to be in multi-buffer mode. This can be accomplished by using +"xdp.frags" as the section name of the XDP program used. + +To represent a packet consisting of multiple frames, a new flag called +XDP_PKT_CONTD is introduced in the options field of the Rx and Tx +descriptors. If it is true (1) the packet continues with the next +descriptor and if it is false (0) it means this is the last descriptor +of the packet. Why the reverse logic of end-of-packet (eop) flag found +in many NICs? Just to preserve compatibility with non-multi-buffer +applications that have this bit set to false for all packets on Rx, +and the apps set the options field to zero for Tx, as anything else +will be treated as an invalid descriptor. + +These are the semantics for producing packets onto AF_XDP Tx ring +consisting of multiple frames: + +* When an invalid descriptor is found, all the other + descriptors/frames of this packet are marked as invalid and not + completed. The next descriptor is treated as the start of a new + packet, even if this was not the intent (because we cannot guess + the intent). As before, if your program is producing invalid + descriptors you have a bug that must be fixed. + +* Zero length descriptors are treated as invalid descriptors. + +* For copy mode, the maximum supported number of frames in a packet is + equal to CONFIG_MAX_SKB_FRAGS + 1. If it is exceeded, all + descriptors accumulated so far are dropped and treated as + invalid. To produce an application that will work on any system + regardless of this config setting, limit the number of frags to 18, + as the minimum value of the config is 17. + +* For zero-copy mode, the limit is up to what the NIC HW + supports. Usually at least five on the NICs we have checked. We + consciously chose to not enforce a rigid limit (such as + CONFIG_MAX_SKB_FRAGS + 1) for zero-copy mode, as it would have + resulted in copy actions under the hood to fit into what limit the + NIC supports. Kind of defeats the purpose of zero-copy mode. How to + probe for this limit is explained in the "probe for multi-buffer + support" section. + +On the Rx path in copy-mode, the xsk core copies the XDP data into +multiple descriptors, if needed, and sets the XDP_PKT_CONTD flag as +detailed before. Zero-copy mode works the same, though the data is not +copied. When the application gets a descriptor with the XDP_PKT_CONTD +flag set to one, it means that the packet consists of multiple buffers +and it continues with the next buffer in the following +descriptor. When a descriptor with XDP_PKT_CONTD == 0 is received, it +means that this is the last buffer of the packet. AF_XDP guarantees +that only a complete packet (all frames in the packet) is sent to the +application. If there is not enough space in the AF_XDP Rx ring, all +frames of the packet will be dropped. + +If application reads a batch of descriptors, using for example the libxdp +interfaces, it is not guaranteed that the batch will end with a full +packet. It might end in the middle of a packet and the rest of the +buffers of that packet will arrive at the beginning of the next batch, +since the libxdp interface does not read the whole ring (unless you +have an enormous batch size or a very small ring size). + +An example program each for Rx and Tx multi-buffer support can be found +later in this document. + +Usage +----- + +In order to use AF_XDP sockets two parts are needed. The +user-space application and the XDP program. For a complete setup and +usage example, please refer to the sample application. The user-space +side is xdpsock_user.c and the XDP side is part of libbpf. + +The XDP code sample included in tools/lib/bpf/xsk.c is the following: + +.. code-block:: c + + SEC("xdp_sock") int xdp_sock_prog(struct xdp_md *ctx) + { + int index = ctx->rx_queue_index; + + // A set entry here means that the corresponding queue_id + // has an active AF_XDP socket bound to it. + if (bpf_map_lookup_elem(&xsks_map, &index)) + return bpf_redirect_map(&xsks_map, index, 0); + + return XDP_PASS; + } + +A simple but not so performance ring dequeue and enqueue could look +like this: + +.. code-block:: c + + // struct xdp_rxtx_ring { + // __u32 *producer; + // __u32 *consumer; + // struct xdp_desc *desc; + // }; + + // struct xdp_umem_ring { + // __u32 *producer; + // __u32 *consumer; + // __u64 *desc; + // }; + + // typedef struct xdp_rxtx_ring RING; + // typedef struct xdp_umem_ring RING; + + // typedef struct xdp_desc RING_TYPE; + // typedef __u64 RING_TYPE; + + int dequeue_one(RING *ring, RING_TYPE *item) + { + __u32 entries = *ring->producer - *ring->consumer; + + if (entries == 0) + return -1; + + // read-barrier! + + *item = ring->desc[*ring->consumer & (RING_SIZE - 1)]; + (*ring->consumer)++; + return 0; + } + + int enqueue_one(RING *ring, const RING_TYPE *item) + { + u32 free_entries = RING_SIZE - (*ring->producer - *ring->consumer); + + if (free_entries == 0) + return -1; + + ring->desc[*ring->producer & (RING_SIZE - 1)] = *item; + + // write-barrier! + + (*ring->producer)++; + return 0; + } + +But please use the libbpf functions as they are optimized and ready to +use. Will make your life easier. + +Usage Multi-Buffer Rx +--------------------- + +Here is a simple Rx path pseudo-code example (using libxdp interfaces +for simplicity). Error paths have been excluded to keep it short: + +.. code-block:: c + + void rx_packets(struct xsk_socket_info *xsk) + { + static bool new_packet = true; + u32 idx_rx = 0, idx_fq = 0; + static char *pkt; + + int rcvd = xsk_ring_cons__peek(&xsk->rx, opt_batch_size, &idx_rx); + + xsk_ring_prod__reserve(&xsk->umem->fq, rcvd, &idx_fq); + + for (int i = 0; i < rcvd; i++) { + struct xdp_desc *desc = xsk_ring_cons__rx_desc(&xsk->rx, idx_rx++); + char *frag = xsk_umem__get_data(xsk->umem->buffer, desc->addr); + bool eop = !(desc->options & XDP_PKT_CONTD); + + if (new_packet) + pkt = frag; + else + add_frag_to_pkt(pkt, frag); + + if (eop) + process_pkt(pkt); + + new_packet = eop; + + *xsk_ring_prod__fill_addr(&xsk->umem->fq, idx_fq++) = desc->addr; + } + + xsk_ring_prod__submit(&xsk->umem->fq, rcvd); + xsk_ring_cons__release(&xsk->rx, rcvd); + } + +Usage Multi-Buffer Tx +--------------------- + +Here is an example Tx path pseudo-code (using libxdp interfaces for +simplicity) ignoring that the umem is finite in size, and that we +eventually will run out of packets to send. Also assumes pkts.addr +points to a valid location in the umem. + +.. code-block:: c + + void tx_packets(struct xsk_socket_info *xsk, struct pkt *pkts, + int batch_size) + { + u32 idx, i, pkt_nb = 0; + + xsk_ring_prod__reserve(&xsk->tx, batch_size, &idx); + + for (i = 0; i < batch_size;) { + u64 addr = pkts[pkt_nb].addr; + u32 len = pkts[pkt_nb].size; + + do { + struct xdp_desc *tx_desc; + + tx_desc = xsk_ring_prod__tx_desc(&xsk->tx, idx + i++); + tx_desc->addr = addr; + + if (len > xsk_frame_size) { + tx_desc->len = xsk_frame_size; + tx_desc->options = XDP_PKT_CONTD; + } else { + tx_desc->len = len; + tx_desc->options = 0; + pkt_nb++; + } + len -= tx_desc->len; + addr += xsk_frame_size; + + if (i == batch_size) { + /* Remember len, addr, pkt_nb for next iteration. + * Skipped for simplicity. + */ + break; + } + } while (len); + } + + xsk_ring_prod__submit(&xsk->tx, i); + } + +Probing for Multi-Buffer Support +-------------------------------- + +To discover if a driver supports multi-buffer AF_XDP in SKB or DRV +mode, use the XDP_FEATURES feature of netlink in linux/netdev.h to +query for NETDEV_XDP_ACT_RX_SG support. This is the same flag as for +querying for XDP multi-buffer support. If XDP supports multi-buffer in +a driver, then AF_XDP will also support that in SKB and DRV mode. + +To discover if a driver supports multi-buffer AF_XDP in zero-copy +mode, use XDP_FEATURES and first check the NETDEV_XDP_ACT_XSK_ZEROCOPY +flag. If it is set, it means that at least zero-copy is supported and +you should go and check the netlink attribute +NETDEV_A_DEV_XDP_ZC_MAX_SEGS in linux/netdev.h. An unsigned integer +value will be returned stating the max number of frags that are +supported by this device in zero-copy mode. These are the possible +return values: + +1: Multi-buffer for zero-copy is not supported by this device, as max + one fragment supported means that multi-buffer is not possible. + +>=2: Multi-buffer is supported in zero-copy mode for this device. The + returned number signifies the max number of frags supported. + +For an example on how these are used through libbpf, please take a +look at tools/testing/selftests/bpf/xskxceiver.c. + +Multi-Buffer Support for Zero-Copy Drivers +------------------------------------------ + +Zero-copy drivers usually use the batched APIs for Rx and Tx +processing. Note that the Tx batch API guarantees that it will provide +a batch of Tx descriptors that ends with full packet at the end. This +to facilitate extending a zero-copy driver with multi-buffer support. + +Sample application +================== + +There is a xdpsock benchmarking/test application included that +demonstrates how to use AF_XDP sockets with private UMEMs. Say that +you would like your UDP traffic from port 4242 to end up in queue 16, +that we will enable AF_XDP on. Here, we use ethtool for this:: + + ethtool -N p3p2 rx-flow-hash udp4 fn + ethtool -N p3p2 flow-type udp4 src-port 4242 dst-port 4242 \ + action 16 + +Running the rxdrop benchmark in XDP_DRV mode can then be done +using:: + + samples/bpf/xdpsock -i p3p2 -q 16 -r -N + +For XDP_SKB mode, use the switch "-S" instead of "-N" and all options +can be displayed with "-h", as usual. + +This sample application uses libbpf to make the setup and usage of +AF_XDP simpler. If you want to know how the raw uapi of AF_XDP is +really used to make something more advanced, take a look at the libbpf +code in tools/lib/bpf/xsk.[ch]. + +FAQ +======= + +Q: I am not seeing any traffic on the socket. What am I doing wrong? + +A: When a netdev of a physical NIC is initialized, Linux usually + allocates one RX and TX queue pair per core. So on a 8 core system, + queue ids 0 to 7 will be allocated, one per core. In the AF_XDP + bind call or the xsk_socket__create libbpf function call, you + specify a specific queue id to bind to and it is only the traffic + towards that queue you are going to get on you socket. So in the + example above, if you bind to queue 0, you are NOT going to get any + traffic that is distributed to queues 1 through 7. If you are + lucky, you will see the traffic, but usually it will end up on one + of the queues you have not bound to. + + There are a number of ways to solve the problem of getting the + traffic you want to the queue id you bound to. If you want to see + all the traffic, you can force the netdev to only have 1 queue, queue + id 0, and then bind to queue 0. You can use ethtool to do this:: + + sudo ethtool -L <interface> combined 1 + + If you want to only see part of the traffic, you can program the + NIC through ethtool to filter out your traffic to a single queue id + that you can bind your XDP socket to. Here is one example in which + UDP traffic to and from port 4242 are sent to queue 2:: + + sudo ethtool -N <interface> rx-flow-hash udp4 fn + sudo ethtool -N <interface> flow-type udp4 src-port 4242 dst-port \ + 4242 action 2 + + A number of other ways are possible all up to the capabilities of + the NIC you have. + +Q: Can I use the XSKMAP to implement a switch between different umems + in copy mode? + +A: The short answer is no, that is not supported at the moment. The + XSKMAP can only be used to switch traffic coming in on queue id X + to sockets bound to the same queue id X. The XSKMAP can contain + sockets bound to different queue ids, for example X and Y, but only + traffic goming in from queue id Y can be directed to sockets bound + to the same queue id Y. In zero-copy mode, you should use the + switch, or other distribution mechanism, in your NIC to direct + traffic to the correct queue id and socket. + +Q: My packets are sometimes corrupted. What is wrong? + +A: Care has to be taken not to feed the same buffer in the UMEM into + more than one ring at the same time. If you for example feed the + same buffer into the FILL ring and the TX ring at the same time, the + NIC might receive data into the buffer at the same time it is + sending it. This will cause some packets to become corrupted. Same + thing goes for feeding the same buffer into the FILL rings + belonging to different queue ids or netdevs bound with the + XDP_SHARED_UMEM flag. + +Credits +======= + +- Björn Töpel (AF_XDP core) +- Magnus Karlsson (AF_XDP core) +- Alexander Duyck +- Alexei Starovoitov +- Daniel Borkmann +- Jesper Dangaard Brouer +- John Fastabend +- Jonathan Corbet (LWN coverage) +- Michael S. Tsirkin +- Qi Z Zhang +- Willem de Bruijn diff --git a/Documentation/networking/alias.rst b/Documentation/networking/alias.rst new file mode 100644 index 0000000000..af7c5ee920 --- /dev/null +++ b/Documentation/networking/alias.rst @@ -0,0 +1,49 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=========== +IP-Aliasing +=========== + +IP-aliases are an obsolete way to manage multiple IP-addresses/masks +per interface. Newer tools such as iproute2 support multiple +address/prefixes per interface, but aliases are still supported +for backwards compatibility. + +An alias is formed by adding a colon and a string when running ifconfig. +This string is usually numeric, but this is not a must. + + +Alias creation +============== + +Alias creation is done by 'magic' interface naming: eg. to create a +200.1.1.1 alias for eth0 ... +:: + + # ifconfig eth0:0 200.1.1.1 etc,etc.... + ~~ -> request alias #0 creation (if not yet exists) for eth0 + +The corresponding route is also set up by this command. Please note: +The route always points to the base interface. + + +Alias deletion +============== + +The alias is removed by shutting the alias down:: + + # ifconfig eth0:0 down + ~~~~~~~~~~ -> will delete alias + + +Alias (re-)configuring +====================== + +Aliases are not real devices, but programs should be able to configure +and refer to them as usual (ifconfig, route, etc). + + +Relationship with main device +============================= + +If the base device is shut down the added aliases will be deleted too. diff --git a/Documentation/networking/arcnet-hardware.rst b/Documentation/networking/arcnet-hardware.rst new file mode 100644 index 0000000000..9822157235 --- /dev/null +++ b/Documentation/networking/arcnet-hardware.rst @@ -0,0 +1,3234 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=============== +ARCnet Hardware +=============== + +.. note:: + + 1) This file is a supplement to arcnet.txt. Please read that for general + driver configuration help. + 2) This file is no longer Linux-specific. It should probably be moved out + of the kernel sources. Ideas? + +Because so many people (myself included) seem to have obtained ARCnet cards +without manuals, this file contains a quick introduction to ARCnet hardware, +some cabling tips, and a listing of all jumper settings I can find. Please +e-mail apenwarr@worldvisions.ca with any settings for your particular card, +or any other information you have! + + +Introduction to ARCnet +====================== + +ARCnet is a network type which works in a way similar to popular Ethernet +networks but which is also different in some very important ways. + +First of all, you can get ARCnet cards in at least two speeds: 2.5 Mbps +(slower than Ethernet) and 100 Mbps (faster than normal Ethernet). In fact, +there are others as well, but these are less common. The different hardware +types, as far as I'm aware, are not compatible and so you cannot wire a +100 Mbps card to a 2.5 Mbps card, and so on. From what I hear, my driver does +work with 100 Mbps cards, but I haven't been able to verify this myself, +since I only have the 2.5 Mbps variety. It is probably not going to saturate +your 100 Mbps card. Stop complaining. :) + +You also cannot connect an ARCnet card to any kind of Ethernet card and +expect it to work. + +There are two "types" of ARCnet - STAR topology and BUS topology. This +refers to how the cards are meant to be wired together. According to most +available documentation, you can only connect STAR cards to STAR cards and +BUS cards to BUS cards. That makes sense, right? Well, it's not quite +true; see below under "Cabling." + +Once you get past these little stumbling blocks, ARCnet is actually quite a +well-designed standard. It uses something called "modified token passing" +which makes it completely incompatible with so-called "Token Ring" cards, +but which makes transfers much more reliable than Ethernet does. In fact, +ARCnet will guarantee that a packet arrives safely at the destination, and +even if it can't possibly be delivered properly (ie. because of a cable +break, or because the destination computer does not exist) it will at least +tell the sender about it. + +Because of the carefully defined action of the "token", it will always make +a pass around the "ring" within a maximum length of time. This makes it +useful for realtime networks. + +In addition, all known ARCnet cards have an (almost) identical programming +interface. This means that with one ARCnet driver you can support any +card, whereas with Ethernet each manufacturer uses what is sometimes a +completely different programming interface, leading to a lot of different, +sometimes very similar, Ethernet drivers. Of course, always using the same +programming interface also means that when high-performance hardware +facilities like PCI bus mastering DMA appear, it's hard to take advantage of +them. Let's not go into that. + +One thing that makes ARCnet cards difficult to program for, however, is the +limit on their packet sizes; standard ARCnet can only send packets that are +up to 508 bytes in length. This is smaller than the Internet "bare minimum" +of 576 bytes, let alone the Ethernet MTU of 1500. To compensate, an extra +level of encapsulation is defined by RFC1201, which I call "packet +splitting," that allows "virtual packets" to grow as large as 64K each, +although they are generally kept down to the Ethernet-style 1500 bytes. + +For more information on the advantages and disadvantages (mostly the +advantages) of ARCnet networks, you might try the "ARCnet Trade Association" +WWW page: + + http://www.arcnet.com + + +Cabling ARCnet Networks +======================= + +This section was rewritten by + + Vojtech Pavlik <vojtech@suse.cz> + +using information from several people, including: + + - Avery Pennraun <apenwarr@worldvisions.ca> + - Stephen A. Wood <saw@hallc1.cebaf.gov> + - John Paul Morrison <jmorriso@bogomips.ee.ubc.ca> + - Joachim Koenig <jojo@repas.de> + +and Avery touched it up a bit, at Vojtech's request. + +ARCnet (the classic 2.5 Mbps version) can be connected by two different +types of cabling: coax and twisted pair. The other ARCnet-type networks +(100 Mbps TCNS and 320 kbps - 32 Mbps ARCnet Plus) use different types of +cabling (Type1, Fiber, C1, C4, C5). + +For a coax network, you "should" use 93 Ohm RG-62 cable. But other cables +also work fine, because ARCnet is a very stable network. I personally use 75 +Ohm TV antenna cable. + +Cards for coax cabling are shipped in two different variants: for BUS and +STAR network topologies. They are mostly the same. The only difference +lies in the hybrid chip installed. BUS cards use high impedance output, +while STAR use low impedance. Low impedance card (STAR) is electrically +equal to a high impedance one with a terminator installed. + +Usually, the ARCnet networks are built up from STAR cards and hubs. There +are two types of hubs - active and passive. Passive hubs are small boxes +with four BNC connectors containing four 47 Ohm resistors:: + + | | wires + R + junction + -R-+-R- R 47 Ohm resistors + R + | + +The shielding is connected together. Active hubs are much more complicated; +they are powered and contain electronics to amplify the signal and send it +to other segments of the net. They usually have eight connectors. Active +hubs come in two variants - dumb and smart. The dumb variant just +amplifies, but the smart one decodes to digital and encodes back all packets +coming through. This is much better if you have several hubs in the net, +since many dumb active hubs may worsen the signal quality. + +And now to the cabling. What you can connect together: + +1. A card to a card. This is the simplest way of creating a 2-computer + network. + +2. A card to a passive hub. Remember that all unused connectors on the hub + must be properly terminated with 93 Ohm (or something else if you don't + have the right ones) terminators. + + (Avery's note: oops, I didn't know that. Mine (TV cable) works + anyway, though.) + +3. A card to an active hub. Here is no need to terminate the unused + connectors except some kind of aesthetic feeling. But, there may not be + more than eleven active hubs between any two computers. That of course + doesn't limit the number of active hubs on the network. + +4. An active hub to another. + +5. An active hub to passive hub. + +Remember that you cannot connect two passive hubs together. The power loss +implied by such a connection is too high for the net to operate reliably. + +An example of a typical ARCnet network:: + + R S - STAR type card + S------H--------A-------S R - Terminator + | | H - Hub + | | A - Active hub + | S----H----S + S | + | + S + +The BUS topology is very similar to the one used by Ethernet. The only +difference is in cable and terminators: they should be 93 Ohm. Ethernet +uses 50 Ohm impedance. You use T connectors to put the computers on a single +line of cable, the bus. You have to put terminators at both ends of the +cable. A typical BUS ARCnet network looks like:: + + RT----T------T------T------T------TR + B B B B B B + + B - BUS type card + R - Terminator + T - T connector + +But that is not all! The two types can be connected together. According to +the official documentation the only way of connecting them is using an active +hub:: + + A------T------T------TR + | B B B + S---H---S + | + S + +The official docs also state that you can use STAR cards at the ends of +BUS network in place of a BUS card and a terminator:: + + S------T------T------S + B B + +But, according to my own experiments, you can simply hang a BUS type card +anywhere in middle of a cable in a STAR topology network. And more - you +can use the bus card in place of any star card if you use a terminator. Then +you can build very complicated networks fulfilling all your needs! An +example:: + + S + | + RT------T-------T------H------S + B B B | + | R + S------A------T-------T-------A-------H------TR + | B B | | B + | S BT | + | | | S----A-----S + S------H---A----S | | + | | S------T----H---S | + S S B R S + +A basically different cabling scheme is used with Twisted Pair cabling. Each +of the TP cards has two RJ (phone-cord style) connectors. The cards are +then daisy-chained together using a cable connecting every two neighboring +cards. The ends are terminated with RJ 93 Ohm terminators which plug into +the empty connectors of cards on the ends of the chain. An example:: + + ___________ ___________ + _R_|_ _|_|_ _|_R_ + | | | | | | + |Card | |Card | |Card | + |_____| |_____| |_____| + + +There are also hubs for the TP topology. There is nothing difficult +involved in using them; you just connect a TP chain to a hub on any end or +even at both. This way you can create almost any network configuration. +The maximum of 11 hubs between any two computers on the net applies here as +well. An example:: + + RP-------P--------P--------H-----P------P-----PR + | + RP-----H--------P--------H-----P------PR + | | + PR PR + + R - RJ Terminator + P - TP Card + H - TP Hub + +Like any network, ARCnet has a limited cable length. These are the maximum +cable lengths between two active ends (an active end being an active hub or +a STAR card). + + ========== ======= =========== + RG-62 93 Ohm up to 650 m + RG-59/U 75 Ohm up to 457 m + RG-11/U 75 Ohm up to 533 m + IBM Type 1 150 Ohm up to 200 m + IBM Type 3 100 Ohm up to 100 m + ========== ======= =========== + +The maximum length of all cables connected to a passive hub is limited to 65 +meters for RG-62 cabling; less for others. You can see that using passive +hubs in a large network is a bad idea. The maximum length of a single "BUS +Trunk" is about 300 meters for RG-62. The maximum distance between the two +most distant points of the net is limited to 3000 meters. The maximum length +of a TP cable between two cards/hubs is 650 meters. + + +Setting the Jumpers +=================== + +All ARCnet cards should have a total of four or five different settings: + + - the I/O address: this is the "port" your ARCnet card is on. Probed + values in the Linux ARCnet driver are only from 0x200 through 0x3F0. (If + your card has additional ones, which is possible, please tell me.) This + should not be the same as any other device on your system. According to + a doc I got from Novell, MS Windows prefers values of 0x300 or more, + eating net connections on my system (at least) otherwise. My guess is + this may be because, if your card is at 0x2E0, probing for a serial port + at 0x2E8 will reset the card and probably mess things up royally. + + - Avery's favourite: 0x300. + + - the IRQ: on 8-bit cards, it might be 2 (9), 3, 4, 5, or 7. + on 16-bit cards, it might be 2 (9), 3, 4, 5, 7, or 10-15. + + Make sure this is different from any other card on your system. Note + that IRQ2 is the same as IRQ9, as far as Linux is concerned. You can + "cat /proc/interrupts" for a somewhat complete list of which ones are in + use at any given time. Here is a list of common usages from Vojtech + Pavlik <vojtech@suse.cz>: + + ("Not on bus" means there is no way for a card to generate this + interrupt) + + ====== ========================================================= + IRQ 0 Timer 0 (Not on bus) + IRQ 1 Keyboard (Not on bus) + IRQ 2 IRQ Controller 2 (Not on bus, nor does interrupt the CPU) + IRQ 3 COM2 + IRQ 4 COM1 + IRQ 5 FREE (LPT2 if you have it; sometimes COM3; maybe PLIP) + IRQ 6 Floppy disk controller + IRQ 7 FREE (LPT1 if you don't use the polling driver; PLIP) + IRQ 8 Realtime Clock Interrupt (Not on bus) + IRQ 9 FREE (VGA vertical sync interrupt if enabled) + IRQ 10 FREE + IRQ 11 FREE + IRQ 12 FREE + IRQ 13 Numeric Coprocessor (Not on bus) + IRQ 14 Fixed Disk Controller + IRQ 15 FREE (Fixed Disk Controller 2 if you have it) + ====== ========================================================= + + + .. note:: + + IRQ 9 is used on some video cards for the "vertical retrace" + interrupt. This interrupt would have been handy for things like + video games, as it occurs exactly once per screen refresh, but + unfortunately IBM cancelled this feature starting with the original + VGA and thus many VGA/SVGA cards do not support it. For this + reason, no modern software uses this interrupt and it can almost + always be safely disabled, if your video card supports it at all. + + If your card for some reason CANNOT disable this IRQ (usually there + is a jumper), one solution would be to clip the printed circuit + contact on the board: it's the fourth contact from the left on the + back side. I take no responsibility if you try this. + + - Avery's favourite: IRQ2 (actually IRQ9). Watch that VGA, though. + + - the memory address: Unlike most cards, ARCnets use "shared memory" for + copying buffers around. Make SURE it doesn't conflict with any other + used memory in your system! + + :: + + A0000 - VGA graphics memory (ok if you don't have VGA) + B0000 - Monochrome text mode + C0000 \ One of these is your VGA BIOS - usually C0000. + E0000 / + F0000 - System BIOS + + Anything less than 0xA0000 is, well, a BAD idea since it isn't above + 640k. + + - Avery's favourite: 0xD0000 + + - the station address: Every ARCnet card has its own "unique" network + address from 0 to 255. Unlike Ethernet, you can set this address + yourself with a jumper or switch (or on some cards, with special + software). Since it's only 8 bits, you can only have 254 ARCnet cards + on a network. DON'T use 0 or 255, since these are reserved (although + neat stuff will probably happen if you DO use them). By the way, if you + haven't already guessed, don't set this the same as any other ARCnet on + your network! + + - Avery's favourite: 3 and 4. Not that it matters. + + - There may be ETS1 and ETS2 settings. These may or may not make a + difference on your card (many manuals call them "reserved"), but are + used to change the delays used when powering up a computer on the + network. This is only necessary when wiring VERY long range ARCnet + networks, on the order of 4km or so; in any case, the only real + requirement here is that all cards on the network with ETS1 and ETS2 + jumpers have them in the same position. Chris Hindy <chrish@io.org> + sent in a chart with actual values for this: + + ======= ======= =============== ==================== + ET1 ET2 Response Time Reconfiguration Time + ======= ======= =============== ==================== + open open 74.7us 840us + open closed 283.4us 1680us + closed open 561.8us 1680us + closed closed 1118.6us 1680us + ======= ======= =============== ==================== + + Make sure you set ETS1 and ETS2 to the SAME VALUE for all cards on your + network. + +Also, on many cards (not mine, though) there are red and green LED's. +Vojtech Pavlik <vojtech@suse.cz> tells me this is what they mean: + + =============== =============== ===================================== + GREEN RED Status + =============== =============== ===================================== + OFF OFF Power off + OFF Short flashes Cabling problems (broken cable or not + terminated) + OFF (short) ON Card init + ON ON Normal state - everything OK, nothing + happens + ON Long flashes Data transfer + ON OFF Never happens (maybe when wrong ID) + =============== =============== ===================================== + + +The following is all the specific information people have sent me about +their own particular ARCnet cards. It is officially a mess, and contains +huge amounts of duplicated information. I have no time to fix it. If you +want to, PLEASE DO! Just send me a 'diff -u' of all your changes. + +The model # is listed right above specifics for that card, so you should be +able to use your text viewer's "search" function to find the entry you want. +If you don't KNOW what kind of card you have, try looking through the +various diagrams to see if you can tell. + +If your model isn't listed and/or has different settings, PLEASE PLEASE +tell me. I had to figure mine out without the manual, and it WASN'T FUN! + +Even if your ARCnet model isn't listed, but has the same jumpers as another +model that is, please e-mail me to say so. + +Cards Listed in this file (in this order, mostly): + + =============== ======================= ==== + Manufacturer Model # Bits + =============== ======================= ==== + SMC PC100 8 + SMC PC110 8 + SMC PC120 8 + SMC PC130 8 + SMC PC270E 8 + SMC PC500 16 + SMC PC500Longboard 16 + SMC PC550Longboard 16 + SMC PC600 16 + SMC PC710 8 + SMC? LCS-8830(-T) 8/16 + Puredata PDI507 8 + CNet Tech CN120-Series 8 + CNet Tech CN160-Series 16 + Lantech? UM9065L chipset 8 + Acer 5210-003 8 + Datapoint? LAN-ARC-8 8 + Topware TA-ARC/10 8 + Thomas-Conrad 500-6242-0097 REV A 8 + Waterloo? (C)1985 Waterloo Micro. 8 + No Name -- 8/16 + No Name Taiwan R.O.C? 8 + No Name Model 9058 8 + Tiara Tiara Lancard? 8 + =============== ======================= ==== + + +* SMC = Standard Microsystems Corp. +* CNet Tech = CNet Technology, Inc. + +Unclassified Stuff +================== + + - Please send any other information you can find. + + - And some other stuff (more info is welcome!):: + + From: root@ultraworld.xs4all.nl (Timo Hilbrink) + To: apenwarr@foxnet.net (Avery Pennarun) + Date: Wed, 26 Oct 1994 02:10:32 +0000 (GMT) + Reply-To: timoh@xs4all.nl + + [...parts deleted...] + + About the jumpers: On my PC130 there is one more jumper, located near the + cable-connector and it's for changing to star or bus topology; + closed: star - open: bus + On the PC500 are some more jumper-pins, one block labeled with RX,PDN,TXI + and another with ALE,LA17,LA18,LA19 these are undocumented.. + + [...more parts deleted...] + + --- CUT --- + +Standard Microsystems Corp (SMC) +================================ + +PC100, PC110, PC120, PC130 (8-bit cards) and PC500, PC600 (16-bit cards) +------------------------------------------------------------------------ + + - mainly from Avery Pennarun <apenwarr@worldvisions.ca>. Values depicted + are from Avery's setup. + - special thanks to Timo Hilbrink <timoh@xs4all.nl> for noting that PC120, + 130, 500, and 600 all have the same switches as Avery's PC100. + PC500/600 have several extra, undocumented pins though. (?) + - PC110 settings were verified by Stephen A. Wood <saw@cebaf.gov> + - Also, the JP- and S-numbers probably don't match your card exactly. Try + to find jumpers/switches with the same number of settings - it's + probably more reliable. + +:: + + JP5 [|] : : : : + (IRQ Setting) IRQ2 IRQ3 IRQ4 IRQ5 IRQ7 + Put exactly one jumper on exactly one set of pins. + + + 1 2 3 4 5 6 7 8 9 10 + S1 /----------------------------------\ + (I/O and Memory | 1 1 * 0 0 0 0 * 1 1 0 1 | + addresses) \----------------------------------/ + |--| |--------| |--------| + (a) (b) (m) + + WARNING. It's very important when setting these which way + you're holding the card, and which way you think is '1'! + + If you suspect that your settings are not being made + correctly, try reversing the direction or inverting the + switch positions. + + a: The first digit of the I/O address. + Setting Value + ------- ----- + 00 0 + 01 1 + 10 2 + 11 3 + + b: The second digit of the I/O address. + Setting Value + ------- ----- + 0000 0 + 0001 1 + 0010 2 + ... ... + 1110 E + 1111 F + + The I/O address is in the form ab0. For example, if + a is 0x2 and b is 0xE, the address will be 0x2E0. + + DO NOT SET THIS LESS THAN 0x200!!!!! + + + m: The first digit of the memory address. + Setting Value + ------- ----- + 0000 0 + 0001 1 + 0010 2 + ... ... + 1110 E + 1111 F + + The memory address is in the form m0000. For example, if + m is D, the address will be 0xD0000. + + DO NOT SET THIS TO C0000, F0000, OR LESS THAN A0000! + + 1 2 3 4 5 6 7 8 + S2 /--------------------------\ + (Station Address) | 1 1 0 0 0 0 0 0 | + \--------------------------/ + + Setting Value + ------- ----- + 00000000 00 + 10000000 01 + 01000000 02 + ... + 01111111 FE + 11111111 FF + + Note that this is binary with the digits reversed! + + DO NOT SET THIS TO 0 OR 255 (0xFF)! + + +PC130E/PC270E (8-bit cards) +--------------------------- + + - from Juergen Seifert <seifert@htwm.de> + +This description has been written by Juergen Seifert <seifert@htwm.de> +using information from the following Original SMC Manual + + "Configuration Guide for ARCNET(R)-PC130E/PC270 Network + Controller Boards Pub. # 900.044A June, 1989" + +ARCNET is a registered trademark of the Datapoint Corporation +SMC is a registered trademark of the Standard Microsystems Corporation + +The PC130E is an enhanced version of the PC130 board, is equipped with a +standard BNC female connector for connection to RG-62/U coax cable. +Since this board is designed both for point-to-point connection in star +networks and for connection to bus networks, it is downwardly compatible +with all the other standard boards designed for coax networks (that is, +the PC120, PC110 and PC100 star topology boards and the PC220, PC210 and +PC200 bus topology boards). + +The PC270E is an enhanced version of the PC260 board, is equipped with two +modular RJ11-type jacks for connection to twisted pair wiring. +It can be used in a star or a daisy-chained network. + +:: + + 8 7 6 5 4 3 2 1 + ________________________________________________________________ + | | S1 | | + | |_________________| | + | Offs|Base |I/O Addr | + | RAM Addr | ___| + | ___ ___ CR3 |___| + | | \/ | CR4 |___| + | | PROM | ___| + | | | N | | 8 + | | SOCKET | o | | 7 + | |________| d | | 6 + | ___________________ e | | 5 + | | | A | S | 4 + | |oo| EXT2 | | d | 2 | 3 + | |oo| EXT1 | SMC | d | | 2 + | |oo| ROM | 90C63 | r |___| 1 + | |oo| IRQ7 | | |o| _____| + | |oo| IRQ5 | | |o| | J1 | + | |oo| IRQ4 | | STAR |_____| + | |oo| IRQ3 | | | J2 | + | |oo| IRQ2 |___________________| |_____| + |___ ______________| + | | + |_____________________________________________| + +Legend:: + + SMC 90C63 ARCNET Controller / Transceiver /Logic + S1 1-3: I/O Base Address Select + 4-6: Memory Base Address Select + 7-8: RAM Offset Select + S2 1-8: Node ID Select + EXT Extended Timeout Select + ROM ROM Enable Select + STAR Selected - Star Topology (PC130E only) + Deselected - Bus Topology (PC130E only) + CR3/CR4 Diagnostic LEDs + J1 BNC RG62/U Connector (PC130E only) + J1 6-position Telephone Jack (PC270E only) + J2 6-position Telephone Jack (PC270E only) + +Setting one of the switches to Off/Open means "1", On/Closed means "0". + + +Setting the Node ID +^^^^^^^^^^^^^^^^^^^ + +The eight switches in group S2 are used to set the node ID. +These switches work in a way similar to the PC100-series cards; see that +entry for more information. + + +Setting the I/O Base Address +^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The first three switches in switch group S1 are used to select one +of eight possible I/O Base addresses using the following table:: + + + Switch | Hex I/O + 1 2 3 | Address + -------|-------- + 0 0 0 | 260 + 0 0 1 | 290 + 0 1 0 | 2E0 (Manufacturer's default) + 0 1 1 | 2F0 + 1 0 0 | 300 + 1 0 1 | 350 + 1 1 0 | 380 + 1 1 1 | 3E0 + + +Setting the Base Memory (RAM) buffer Address +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The memory buffer requires 2K of a 16K block of RAM. The base of this +16K block can be located in any of eight positions. +Switches 4-6 of switch group S1 select the Base of the 16K block. +Within that 16K address space, the buffer may be assigned any one of four +positions, determined by the offset, switches 7 and 8 of group S1. + +:: + + Switch | Hex RAM | Hex ROM + 4 5 6 7 8 | Address | Address *) + -----------|---------|----------- + 0 0 0 0 0 | C0000 | C2000 + 0 0 0 0 1 | C0800 | C2000 + 0 0 0 1 0 | C1000 | C2000 + 0 0 0 1 1 | C1800 | C2000 + | | + 0 0 1 0 0 | C4000 | C6000 + 0 0 1 0 1 | C4800 | C6000 + 0 0 1 1 0 | C5000 | C6000 + 0 0 1 1 1 | C5800 | C6000 + | | + 0 1 0 0 0 | CC000 | CE000 + 0 1 0 0 1 | CC800 | CE000 + 0 1 0 1 0 | CD000 | CE000 + 0 1 0 1 1 | CD800 | CE000 + | | + 0 1 1 0 0 | D0000 | D2000 (Manufacturer's default) + 0 1 1 0 1 | D0800 | D2000 + 0 1 1 1 0 | D1000 | D2000 + 0 1 1 1 1 | D1800 | D2000 + | | + 1 0 0 0 0 | D4000 | D6000 + 1 0 0 0 1 | D4800 | D6000 + 1 0 0 1 0 | D5000 | D6000 + 1 0 0 1 1 | D5800 | D6000 + | | + 1 0 1 0 0 | D8000 | DA000 + 1 0 1 0 1 | D8800 | DA000 + 1 0 1 1 0 | D9000 | DA000 + 1 0 1 1 1 | D9800 | DA000 + | | + 1 1 0 0 0 | DC000 | DE000 + 1 1 0 0 1 | DC800 | DE000 + 1 1 0 1 0 | DD000 | DE000 + 1 1 0 1 1 | DD800 | DE000 + | | + 1 1 1 0 0 | E0000 | E2000 + 1 1 1 0 1 | E0800 | E2000 + 1 1 1 1 0 | E1000 | E2000 + 1 1 1 1 1 | E1800 | E2000 + + *) To enable the 8K Boot PROM install the jumper ROM. + The default is jumper ROM not installed. + + +Setting the Timeouts and Interrupt +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The jumpers labeled EXT1 and EXT2 are used to determine the timeout +parameters. These two jumpers are normally left open. + +To select a hardware interrupt level set one (only one!) of the jumpers +IRQ2, IRQ3, IRQ4, IRQ5, IRQ7. The Manufacturer's default is IRQ2. + + +Configuring the PC130E for Star or Bus Topology +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The single jumper labeled STAR is used to configure the PC130E board for +star or bus topology. +When the jumper is installed, the board may be used in a star network, when +it is removed, the board can be used in a bus topology. + + +Diagnostic LEDs +^^^^^^^^^^^^^^^ + +Two diagnostic LEDs are visible on the rear bracket of the board. +The green LED monitors the network activity: the red one shows the +board activity:: + + Green | Status Red | Status + -------|------------------- ---------|------------------- + on | normal activity flash/on | data transfer + blink | reconfiguration off | no data transfer; + off | defective board or | incorrect memory or + | node ID is zero | I/O address + + +PC500/PC550 Longboard (16-bit cards) +------------------------------------ + + - from Juergen Seifert <seifert@htwm.de> + + + .. note:: + + There is another Version of the PC500 called Short Version, which + is different in hard- and software! The most important differences + are: + + - The long board has no Shared memory. + - On the long board the selection of the interrupt is done by binary + coded switch, on the short board directly by jumper. + +[Avery's note: pay special attention to that: the long board HAS NO SHARED +MEMORY. This means the current Linux-ARCnet driver can't use these cards. +I have obtained a PC500Longboard and will be doing some experiments on it in +the future, but don't hold your breath. Thanks again to Juergen Seifert for +his advice about this!] + +This description has been written by Juergen Seifert <seifert@htwm.de> +using information from the following Original SMC Manual + + "Configuration Guide for SMC ARCNET-PC500/PC550 + Series Network Controller Boards Pub. # 900.033 Rev. A + November, 1989" + +ARCNET is a registered trademark of the Datapoint Corporation +SMC is a registered trademark of the Standard Microsystems Corporation + +The PC500 is equipped with a standard BNC female connector for connection +to RG-62/U coax cable. +The board is designed both for point-to-point connection in star networks +and for connection to bus networks. + +The PC550 is equipped with two modular RJ11-type jacks for connection +to twisted pair wiring. +It can be used in a star or a daisy-chained (BUS) network. + +:: + + 1 + 0 9 8 7 6 5 4 3 2 1 6 5 4 3 2 1 + ____________________________________________________________________ + < | SW1 | | SW2 | | + > |_____________________| |_____________| | + < IRQ |I/O Addr | + > ___| + < CR4 |___| + > CR3 |___| + < ___| + > N | | 8 + < o | | 7 + > d | S | 6 + < e | W | 5 + > A | 3 | 4 + < d | | 3 + > d | | 2 + < r |___| 1 + > |o| _____| + < |o| | J1 | + > 3 1 JP6 |_____| + < |o|o| JP2 | J2 | + > |o|o| |_____| + < 4 2__ ______________| + > | | | + <____| |_____________________________________________| + +Legend:: + + SW1 1-6: I/O Base Address Select + 7-10: Interrupt Select + SW2 1-6: Reserved for Future Use + SW3 1-8: Node ID Select + JP2 1-4: Extended Timeout Select + JP6 Selected - Star Topology (PC500 only) + Deselected - Bus Topology (PC500 only) + CR3 Green Monitors Network Activity + CR4 Red Monitors Board Activity + J1 BNC RG62/U Connector (PC500 only) + J1 6-position Telephone Jack (PC550 only) + J2 6-position Telephone Jack (PC550 only) + +Setting one of the switches to Off/Open means "1", On/Closed means "0". + + +Setting the Node ID +^^^^^^^^^^^^^^^^^^^ + +The eight switches in group SW3 are used to set the node ID. Each node +attached to the network must have an unique node ID which must be +different from 0. +Switch 1 serves as the least significant bit (LSB). + +The node ID is the sum of the values of all switches set to "1" +These values are:: + + Switch | Value + -------|------- + 1 | 1 + 2 | 2 + 3 | 4 + 4 | 8 + 5 | 16 + 6 | 32 + 7 | 64 + 8 | 128 + +Some Examples:: + + Switch | Hex | Decimal + 8 7 6 5 4 3 2 1 | Node ID | Node ID + ----------------|---------|--------- + 0 0 0 0 0 0 0 0 | not allowed + 0 0 0 0 0 0 0 1 | 1 | 1 + 0 0 0 0 0 0 1 0 | 2 | 2 + 0 0 0 0 0 0 1 1 | 3 | 3 + . . . | | + 0 1 0 1 0 1 0 1 | 55 | 85 + . . . | | + 1 0 1 0 1 0 1 0 | AA | 170 + . . . | | + 1 1 1 1 1 1 0 1 | FD | 253 + 1 1 1 1 1 1 1 0 | FE | 254 + 1 1 1 1 1 1 1 1 | FF | 255 + + +Setting the I/O Base Address +^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The first six switches in switch group SW1 are used to select one +of 32 possible I/O Base addresses using the following table:: + + Switch | Hex I/O + 6 5 4 3 2 1 | Address + -------------|-------- + 0 1 0 0 0 0 | 200 + 0 1 0 0 0 1 | 210 + 0 1 0 0 1 0 | 220 + 0 1 0 0 1 1 | 230 + 0 1 0 1 0 0 | 240 + 0 1 0 1 0 1 | 250 + 0 1 0 1 1 0 | 260 + 0 1 0 1 1 1 | 270 + 0 1 1 0 0 0 | 280 + 0 1 1 0 0 1 | 290 + 0 1 1 0 1 0 | 2A0 + 0 1 1 0 1 1 | 2B0 + 0 1 1 1 0 0 | 2C0 + 0 1 1 1 0 1 | 2D0 + 0 1 1 1 1 0 | 2E0 (Manufacturer's default) + 0 1 1 1 1 1 | 2F0 + 1 1 0 0 0 0 | 300 + 1 1 0 0 0 1 | 310 + 1 1 0 0 1 0 | 320 + 1 1 0 0 1 1 | 330 + 1 1 0 1 0 0 | 340 + 1 1 0 1 0 1 | 350 + 1 1 0 1 1 0 | 360 + 1 1 0 1 1 1 | 370 + 1 1 1 0 0 0 | 380 + 1 1 1 0 0 1 | 390 + 1 1 1 0 1 0 | 3A0 + 1 1 1 0 1 1 | 3B0 + 1 1 1 1 0 0 | 3C0 + 1 1 1 1 0 1 | 3D0 + 1 1 1 1 1 0 | 3E0 + 1 1 1 1 1 1 | 3F0 + + +Setting the Interrupt +^^^^^^^^^^^^^^^^^^^^^ + +Switches seven through ten of switch group SW1 are used to select the +interrupt level. The interrupt level is binary coded, so selections +from 0 to 15 would be possible, but only the following eight values will +be supported: 3, 4, 5, 7, 9, 10, 11, 12. + +:: + + Switch | IRQ + 10 9 8 7 | + ---------|-------- + 0 0 1 1 | 3 + 0 1 0 0 | 4 + 0 1 0 1 | 5 + 0 1 1 1 | 7 + 1 0 0 1 | 9 (=2) (default) + 1 0 1 0 | 10 + 1 0 1 1 | 11 + 1 1 0 0 | 12 + + +Setting the Timeouts +^^^^^^^^^^^^^^^^^^^^ + +The two jumpers JP2 (1-4) are used to determine the timeout parameters. +These two jumpers are normally left open. +Refer to the COM9026 Data Sheet for alternate configurations. + + +Configuring the PC500 for Star or Bus Topology +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The single jumper labeled JP6 is used to configure the PC500 board for +star or bus topology. +When the jumper is installed, the board may be used in a star network, when +it is removed, the board can be used in a bus topology. + + +Diagnostic LEDs +^^^^^^^^^^^^^^^ + +Two diagnostic LEDs are visible on the rear bracket of the board. +The green LED monitors the network activity: the red one shows the +board activity:: + + Green | Status Red | Status + -------|------------------- ---------|------------------- + on | normal activity flash/on | data transfer + blink | reconfiguration off | no data transfer; + off | defective board or | incorrect memory or + | node ID is zero | I/O address + + +PC710 (8-bit card) +------------------ + + - from J.S. van Oosten <jvoosten@compiler.tdcnet.nl> + +Note: this data is gathered by experimenting and looking at info of other +cards. However, I'm sure I got 99% of the settings right. + +The SMC710 card resembles the PC270 card, but is much more basic (i.e. no +LEDs, RJ11 jacks, etc.) and 8 bit. Here's a little drawing:: + + _______________________________________ + | +---------+ +---------+ |____ + | | S2 | | S1 | | + | +---------+ +---------+ | + | | + | +===+ __ | + | | R | | | X-tal ###___ + | | O | |__| ####__'| + | | M | || ### + | +===+ | + | | + | .. JP1 +----------+ | + | .. | big chip | | + | .. | 90C63 | | + | .. | | | + | .. +----------+ | + ------- ----------- + ||||||||||||||||||||| + +The row of jumpers at JP1 actually consists of 8 jumpers, (sometimes +labelled) the same as on the PC270, from top to bottom: EXT2, EXT1, ROM, +IRQ7, IRQ5, IRQ4, IRQ3, IRQ2 (gee, wonder what they would do? :-) ) + +S1 and S2 perform the same function as on the PC270, only their numbers +are swapped (S1 is the nodeaddress, S2 sets IO- and RAM-address). + +I know it works when connected to a PC110 type ARCnet board. + + +***************************************************************************** + +Possibly SMC +============ + +LCS-8830(-T) (8 and 16-bit cards) +--------------------------------- + + - from Mathias Katzer <mkatzer@HRZ.Uni-Bielefeld.DE> + - Marek Michalkiewicz <marekm@i17linuxb.ists.pwr.wroc.pl> says the + LCS-8830 is slightly different from LCS-8830-T. These are 8 bit, BUS + only (the JP0 jumper is hardwired), and BNC only. + +This is a LCS-8830-T made by SMC, I think ('SMC' only appears on one PLCC, +nowhere else, not even on the few Xeroxed sheets from the manual). + +SMC ARCnet Board Type LCS-8830-T:: + + ------------------------------------ + | | + | JP3 88 8 JP2 | + | ##### | \ | + | ##### ET1 ET2 ###| + | 8 ###| + | U3 SW 1 JP0 ###| Phone Jacks + | -- ###| + | | | | + | | | SW2 | + | | | | + | | | ##### | + | -- ##### #### BNC Connector + | #### + | 888888 JP1 | + | 234567 | + -- ------- + ||||||||||||||||||||||||||| + -------------------------- + + + SW1: DIP-Switches for Station Address + SW2: DIP-Switches for Memory Base and I/O Base addresses + + JP0: If closed, internal termination on (default open) + JP1: IRQ Jumpers + JP2: Boot-ROM enabled if closed + JP3: Jumpers for response timeout + + U3: Boot-ROM Socket + + + ET1 ET2 Response Time Idle Time Reconfiguration Time + + 78 86 840 + X 285 316 1680 + X 563 624 1680 + X X 1130 1237 1680 + + (X means closed jumper) + + (DIP-Switch downwards means "0") + +The station address is binary-coded with SW1. + +The I/O base address is coded with DIP-Switches 6,7 and 8 of SW2: + +======== ======== +Switches Base +678 Address +======== ======== +000 260-26f +100 290-29f +010 2e0-2ef +110 2f0-2ff +001 300-30f +101 350-35f +011 380-38f +111 3e0-3ef +======== ======== + + +DIP Switches 1-5 of SW2 encode the RAM and ROM Address Range: + +======== ============= ================ +Switches RAM ROM +12345 Address Range Address Range +======== ============= ================ +00000 C:0000-C:07ff C:2000-C:3fff +10000 C:0800-C:0fff +01000 C:1000-C:17ff +11000 C:1800-C:1fff +00100 C:4000-C:47ff C:6000-C:7fff +10100 C:4800-C:4fff +01100 C:5000-C:57ff +11100 C:5800-C:5fff +00010 C:C000-C:C7ff C:E000-C:ffff +10010 C:C800-C:Cfff +01010 C:D000-C:D7ff +11010 C:D800-C:Dfff +00110 D:0000-D:07ff D:2000-D:3fff +10110 D:0800-D:0fff +01110 D:1000-D:17ff +11110 D:1800-D:1fff +00001 D:4000-D:47ff D:6000-D:7fff +10001 D:4800-D:4fff +01001 D:5000-D:57ff +11001 D:5800-D:5fff +00101 D:8000-D:87ff D:A000-D:bfff +10101 D:8800-D:8fff +01101 D:9000-D:97ff +11101 D:9800-D:9fff +00011 D:C000-D:c7ff D:E000-D:ffff +10011 D:C800-D:cfff +01011 D:D000-D:d7ff +11011 D:D800-D:dfff +00111 E:0000-E:07ff E:2000-E:3fff +10111 E:0800-E:0fff +01111 E:1000-E:17ff +11111 E:1800-E:1fff +======== ============= ================ + + +PureData Corp +============= + +PDI507 (8-bit card) +-------------------- + + - from Mark Rejhon <mdrejhon@magi.com> (slight modifications by Avery) + - Avery's note: I think PDI508 cards (but definitely NOT PDI508Plus cards) + are mostly the same as this. PDI508Plus cards appear to be mainly + software-configured. + +Jumpers: + + There is a jumper array at the bottom of the card, near the edge + connector. This array is labelled J1. They control the IRQs and + something else. Put only one jumper on the IRQ pins. + + ETS1, ETS2 are for timing on very long distance networks. See the + more general information near the top of this file. + + There is a J2 jumper on two pins. A jumper should be put on them, + since it was already there when I got the card. I don't know what + this jumper is for though. + + There is a two-jumper array for J3. I don't know what it is for, + but there were already two jumpers on it when I got the card. It's + a six pin grid in a two-by-three fashion. The jumpers were + configured as follows:: + + .-------. + o | o o | + :-------: ------> Accessible end of card with connectors + o | o o | in this direction -------> + `-------' + +Carl de Billy <CARL@carainfo.com> explains J3 and J4: + + J3 Diagram:: + + .-------. + o | o o | + :-------: TWIST Technology + o | o o | + `-------' + .-------. + | o o | o + :-------: COAX Technology + | o o | o + `-------' + + - If using coax cable in a bus topology the J4 jumper must be removed; + place it on one pin. + + - If using bus topology with twisted pair wiring move the J3 + jumpers so they connect the middle pin and the pins closest to the RJ11 + Connectors. Also the J4 jumper must be removed; place it on one pin of + J4 jumper for storage. + + - If using star topology with twisted pair wiring move the J3 + jumpers so they connect the middle pin and the pins closest to the RJ11 + connectors. + + +DIP Switches: + + The DIP switches accessible on the accessible end of the card while + it is installed, is used to set the ARCnet address. There are 8 + switches. Use an address from 1 to 254 + + ========== ========================= + Switch No. ARCnet address + 12345678 + ========== ========================= + 00000000 FF (Don't use this!) + 00000001 FE + 00000010 FD + ... + 11111101 2 + 11111110 1 + 11111111 0 (Don't use this!) + ========== ========================= + + There is another array of eight DIP switches at the top of the + card. There are five labelled MS0-MS4 which seem to control the + memory address, and another three labelled IO0-IO2 which seem to + control the base I/O address of the card. + + This was difficult to test by trial and error, and the I/O addresses + are in a weird order. This was tested by setting the DIP switches, + rebooting the computer, and attempting to load ARCETHER at various + addresses (mostly between 0x200 and 0x400). The address that caused + the red transmit LED to blink, is the one that I thought works. + + Also, the address 0x3D0 seem to have a special meaning, since the + ARCETHER packet driver loaded fine, but without the red LED + blinking. I don't know what 0x3D0 is for though. I recommend using + an address of 0x300 since Windows may not like addresses below + 0x300. + + ============= =========== + IO Switch No. I/O address + 210 + ============= =========== + 111 0x260 + 110 0x290 + 101 0x2E0 + 100 0x2F0 + 011 0x300 + 010 0x350 + 001 0x380 + 000 0x3E0 + ============= =========== + + The memory switches set a reserved address space of 0x1000 bytes + (0x100 segment units, or 4k). For example if I set an address of + 0xD000, it will use up addresses 0xD000 to 0xD100. + + The memory switches were tested by booting using QEMM386 stealth, + and using LOADHI to see what address automatically became excluded + from the upper memory regions, and then attempting to load ARCETHER + using these addresses. + + I recommend using an ARCnet memory address of 0xD000, and putting + the EMS page frame at 0xC000 while using QEMM stealth mode. That + way, you get contiguous high memory from 0xD100 almost all the way + the end of the megabyte. + + Memory Switch 0 (MS0) didn't seem to work properly when set to OFF + on my card. It could be malfunctioning on my card. Experiment with + it ON first, and if it doesn't work, set it to OFF. (It may be a + modifier for the 0x200 bit?) + + ============= ============================================ + MS Switch No. + 43210 Memory address + ============= ============================================ + 00001 0xE100 (guessed - was not detected by QEMM) + 00011 0xE000 (guessed - was not detected by QEMM) + 00101 0xDD00 + 00111 0xDC00 + 01001 0xD900 + 01011 0xD800 + 01101 0xD500 + 01111 0xD400 + 10001 0xD100 + 10011 0xD000 + 10101 0xCD00 + 10111 0xCC00 + 11001 0xC900 (guessed - crashes tested system) + 11011 0xC800 (guessed - crashes tested system) + 11101 0xC500 (guessed - crashes tested system) + 11111 0xC400 (guessed - crashes tested system) + ============= ============================================ + +CNet Technology Inc. (8-bit cards) +================================== + +120 Series (8-bit cards) +------------------------ + - from Juergen Seifert <seifert@htwm.de> + +This description has been written by Juergen Seifert <seifert@htwm.de> +using information from the following Original CNet Manual + + "ARCNET USER'S MANUAL for + CN120A + CN120AB + CN120TP + CN120ST + CN120SBT + P/N:12-01-0007 + Revision 3.00" + +ARCNET is a registered trademark of the Datapoint Corporation + +- P/N 120A ARCNET 8 bit XT/AT Star +- P/N 120AB ARCNET 8 bit XT/AT Bus +- P/N 120TP ARCNET 8 bit XT/AT Twisted Pair +- P/N 120ST ARCNET 8 bit XT/AT Star, Twisted Pair +- P/N 120SBT ARCNET 8 bit XT/AT Star, Bus, Twisted Pair + +:: + + __________________________________________________________________ + | | + | ___| + | LED |___| + | ___| + | N | | ID7 + | o | | ID6 + | d | S | ID5 + | e | W | ID4 + | ___________________ A | 2 | ID3 + | | | d | | ID2 + | | | 1 2 3 4 5 6 7 8 d | | ID1 + | | | _________________ r |___| ID0 + | | 90C65 || SW1 | ____| + | JP 8 7 | ||_________________| | | + | |o|o| JP1 | | | J2 | + | |o|o| |oo| | | JP 1 1 1 | | + | ______________ | | 0 1 2 |____| + | | PROM | |___________________| |o|o|o| _____| + | > SOCKET | JP 6 5 4 3 2 |o|o|o| | J1 | + | |______________| |o|o|o|o|o| |o|o|o| |_____| + |_____ |o|o|o|o|o| ______________| + | | + |_____________________________________________| + +Legend:: + + 90C65 ARCNET Probe + S1 1-5: Base Memory Address Select + 6-8: Base I/O Address Select + S2 1-8: Node ID Select (ID0-ID7) + JP1 ROM Enable Select + JP2 IRQ2 + JP3 IRQ3 + JP4 IRQ4 + JP5 IRQ5 + JP6 IRQ7 + JP7/JP8 ET1, ET2 Timeout Parameters + JP10/JP11 Coax / Twisted Pair Select (CN120ST/SBT only) + JP12 Terminator Select (CN120AB/ST/SBT only) + J1 BNC RG62/U Connector (all except CN120TP) + J2 Two 6-position Telephone Jack (CN120TP/ST/SBT only) + +Setting one of the switches to Off means "1", On means "0". + + +Setting the Node ID +^^^^^^^^^^^^^^^^^^^ + +The eight switches in SW2 are used to set the node ID. Each node attached +to the network must have an unique node ID which must be different from 0. +Switch 1 (ID0) serves as the least significant bit (LSB). + +The node ID is the sum of the values of all switches set to "1" +These values are: + + ======= ====== ===== + Switch Label Value + ======= ====== ===== + 1 ID0 1 + 2 ID1 2 + 3 ID2 4 + 4 ID3 8 + 5 ID4 16 + 6 ID5 32 + 7 ID6 64 + 8 ID7 128 + ======= ====== ===== + +Some Examples:: + + Switch | Hex | Decimal + 8 7 6 5 4 3 2 1 | Node ID | Node ID + ----------------|---------|--------- + 0 0 0 0 0 0 0 0 | not allowed + 0 0 0 0 0 0 0 1 | 1 | 1 + 0 0 0 0 0 0 1 0 | 2 | 2 + 0 0 0 0 0 0 1 1 | 3 | 3 + . . . | | + 0 1 0 1 0 1 0 1 | 55 | 85 + . . . | | + 1 0 1 0 1 0 1 0 | AA | 170 + . . . | | + 1 1 1 1 1 1 0 1 | FD | 253 + 1 1 1 1 1 1 1 0 | FE | 254 + 1 1 1 1 1 1 1 1 | FF | 255 + + +Setting the I/O Base Address +^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The last three switches in switch block SW1 are used to select one +of eight possible I/O Base addresses using the following table:: + + + Switch | Hex I/O + 6 7 8 | Address + ------------|-------- + ON ON ON | 260 + OFF ON ON | 290 + ON OFF ON | 2E0 (Manufacturer's default) + OFF OFF ON | 2F0 + ON ON OFF | 300 + OFF ON OFF | 350 + ON OFF OFF | 380 + OFF OFF OFF | 3E0 + + +Setting the Base Memory (RAM) buffer Address +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The memory buffer (RAM) requires 2K. The base of this buffer can be +located in any of eight positions. The address of the Boot Prom is +memory base + 8K or memory base + 0x2000. +Switches 1-5 of switch block SW1 select the Memory Base address. + +:: + + Switch | Hex RAM | Hex ROM + 1 2 3 4 5 | Address | Address *) + --------------------|---------|----------- + ON ON ON ON ON | C0000 | C2000 + ON ON OFF ON ON | C4000 | C6000 + ON ON ON OFF ON | CC000 | CE000 + ON ON OFF OFF ON | D0000 | D2000 (Manufacturer's default) + ON ON ON ON OFF | D4000 | D6000 + ON ON OFF ON OFF | D8000 | DA000 + ON ON ON OFF OFF | DC000 | DE000 + ON ON OFF OFF OFF | E0000 | E2000 + + *) To enable the Boot ROM install the jumper JP1 + +.. note:: + + Since the switches 1 and 2 are always set to ON it may be possible + that they can be used to add an offset of 2K, 4K or 6K to the base + address, but this feature is not documented in the manual and I + haven't tested it yet. + + +Setting the Interrupt Line +^^^^^^^^^^^^^^^^^^^^^^^^^^ + +To select a hardware interrupt level install one (only one!) of the jumpers +JP2, JP3, JP4, JP5, JP6. JP2 is the default:: + + Jumper | IRQ + -------|----- + 2 | 2 + 3 | 3 + 4 | 4 + 5 | 5 + 6 | 7 + + +Setting the Internal Terminator on CN120AB/TP/SBT +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The jumper JP12 is used to enable the internal terminator:: + + ----- + 0 | 0 | + ----- ON | | ON + | 0 | | 0 | + | | OFF ----- OFF + | 0 | 0 + ----- + Terminator Terminator + disabled enabled + + +Selecting the Connector Type on CN120ST/SBT +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +:: + + JP10 JP11 JP10 JP11 + ----- ----- + 0 0 | 0 | | 0 | + ----- ----- | | | | + | 0 | | 0 | | 0 | | 0 | + | | | | ----- ----- + | 0 | | 0 | 0 0 + ----- ----- + Coaxial Cable Twisted Pair Cable + (Default) + + +Setting the Timeout Parameters +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The jumpers labeled EXT1 and EXT2 are used to determine the timeout +parameters. These two jumpers are normally left open. + + +CNet Technology Inc. (16-bit cards) +=================================== + +160 Series (16-bit cards) +------------------------- + - from Juergen Seifert <seifert@htwm.de> + +This description has been written by Juergen Seifert <seifert@htwm.de> +using information from the following Original CNet Manual + + "ARCNET USER'S MANUAL for + CN160A CN160AB CN160TP + P/N:12-01-0006 Revision 3.00" + +ARCNET is a registered trademark of the Datapoint Corporation + +- P/N 160A ARCNET 16 bit XT/AT Star +- P/N 160AB ARCNET 16 bit XT/AT Bus +- P/N 160TP ARCNET 16 bit XT/AT Twisted Pair + +:: + + ___________________________________________________________________ + < _________________________ ___| + > |oo| JP2 | | LED |___| + < |oo| JP1 | 9026 | LED |___| + > |_________________________| ___| + < N | | ID7 + > 1 o | | ID6 + < 1 2 3 4 5 6 7 8 9 0 d | S | ID5 + > _______________ _____________________ e | W | ID4 + < | PROM | | SW1 | A | 2 | ID3 + > > SOCKET | |_____________________| d | | ID2 + < |_______________| | IO-Base | MEM | d | | ID1 + > r |___| ID0 + < ____| + > | | + < | J1 | + > | | + < |____| + > 1 1 1 1 | + < 3 4 5 6 7 JP 8 9 0 1 2 3 | + > |o|o|o|o|o| |o|o|o|o|o|o| | + < |o|o|o|o|o| __ |o|o|o|o|o|o| ___________| + > | | | + <____________| |_______________________________________| + +Legend:: + + 9026 ARCNET Probe + SW1 1-6: Base I/O Address Select + 7-10: Base Memory Address Select + SW2 1-8: Node ID Select (ID0-ID7) + JP1/JP2 ET1, ET2 Timeout Parameters + JP3-JP13 Interrupt Select + J1 BNC RG62/U Connector (CN160A/AB only) + J1 Two 6-position Telephone Jack (CN160TP only) + LED + +Setting one of the switches to Off means "1", On means "0". + + +Setting the Node ID +^^^^^^^^^^^^^^^^^^^ + +The eight switches in SW2 are used to set the node ID. Each node attached +to the network must have an unique node ID which must be different from 0. +Switch 1 (ID0) serves as the least significant bit (LSB). + +The node ID is the sum of the values of all switches set to "1" +These values are:: + + Switch | Label | Value + -------|-------|------- + 1 | ID0 | 1 + 2 | ID1 | 2 + 3 | ID2 | 4 + 4 | ID3 | 8 + 5 | ID4 | 16 + 6 | ID5 | 32 + 7 | ID6 | 64 + 8 | ID7 | 128 + +Some Examples:: + + Switch | Hex | Decimal + 8 7 6 5 4 3 2 1 | Node ID | Node ID + ----------------|---------|--------- + 0 0 0 0 0 0 0 0 | not allowed + 0 0 0 0 0 0 0 1 | 1 | 1 + 0 0 0 0 0 0 1 0 | 2 | 2 + 0 0 0 0 0 0 1 1 | 3 | 3 + . . . | | + 0 1 0 1 0 1 0 1 | 55 | 85 + . . . | | + 1 0 1 0 1 0 1 0 | AA | 170 + . . . | | + 1 1 1 1 1 1 0 1 | FD | 253 + 1 1 1 1 1 1 1 0 | FE | 254 + 1 1 1 1 1 1 1 1 | FF | 255 + + +Setting the I/O Base Address +^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The first six switches in switch block SW1 are used to select the I/O Base +address using the following table:: + + Switch | Hex I/O + 1 2 3 4 5 6 | Address + ------------------------|-------- + OFF ON ON OFF OFF ON | 260 + OFF ON OFF ON ON OFF | 290 + OFF ON OFF OFF OFF ON | 2E0 (Manufacturer's default) + OFF ON OFF OFF OFF OFF | 2F0 + OFF OFF ON ON ON ON | 300 + OFF OFF ON OFF ON OFF | 350 + OFF OFF OFF ON ON ON | 380 + OFF OFF OFF OFF OFF ON | 3E0 + +Note: Other IO-Base addresses seem to be selectable, but only the above + combinations are documented. + + +Setting the Base Memory (RAM) buffer Address +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The switches 7-10 of switch block SW1 are used to select the Memory +Base address of the RAM (2K) and the PROM:: + + Switch | Hex RAM | Hex ROM + 7 8 9 10 | Address | Address + ----------------|---------|----------- + OFF OFF ON ON | C0000 | C8000 + OFF OFF ON OFF | D0000 | D8000 (Default) + OFF OFF OFF ON | E0000 | E8000 + +.. note:: + + Other MEM-Base addresses seem to be selectable, but only the above + combinations are documented. + + +Setting the Interrupt Line +^^^^^^^^^^^^^^^^^^^^^^^^^^ + +To select a hardware interrupt level install one (only one!) of the jumpers +JP3 through JP13 using the following table:: + + Jumper | IRQ + -------|----------------- + 3 | 14 + 4 | 15 + 5 | 12 + 6 | 11 + 7 | 10 + 8 | 3 + 9 | 4 + 10 | 5 + 11 | 6 + 12 | 7 + 13 | 2 (=9) Default! + +.. note:: + + - Do not use JP11=IRQ6, it may conflict with your Floppy Disk + Controller + - Use JP3=IRQ14 only, if you don't have an IDE-, MFM-, or RLL- + Hard Disk, it may conflict with their controllers + + +Setting the Timeout Parameters +------------------------------ + +The jumpers labeled JP1 and JP2 are used to determine the timeout +parameters. These two jumpers are normally left open. + + +Lantech +======= + +8-bit card, unknown model +------------------------- + - from Vlad Lungu <vlungu@ugal.ro> - his e-mail address seemed broken at + the time I tried to reach him. Sorry Vlad, if you didn't get my reply. + +:: + + ________________________________________________________________ + | 1 8 | + | ___________ __| + | | SW1 | LED |__| + | |__________| | + | ___| + | _____________________ |S | 8 + | | | |W | + | | | |2 | + | | | |__| 1 + | | UM9065L | |o| JP4 ____|____ + | | | |o| | CN | + | | | |________| + | | | | + | |___________________| | + | | + | | + | _____________ | + | | | | + | | PROM | |ooooo| JP6 | + | |____________| |ooooo| | + |_____________ _ _| + |____________________________________________| |__| + + +UM9065L : ARCnet Controller + +SW 1 : Shared Memory Address and I/O Base + +:: + + ON=0 + + 12345|Memory Address + -----|-------------- + 00001| D4000 + 00010| CC000 + 00110| D0000 + 01110| D1000 + 01101| D9000 + 10010| CC800 + 10011| DC800 + 11110| D1800 + +It seems that the bits are considered in reverse order. Also, you must +observe that some of those addresses are unusual and I didn't probe them; I +used a memory dump in DOS to identify them. For the 00000 configuration and +some others that I didn't write here the card seems to conflict with the +video card (an S3 GENDAC). I leave the full decoding of those addresses to +you. + +:: + + 678| I/O Address + ---|------------ + 000| 260 + 001| failed probe + 010| 2E0 + 011| 380 + 100| 290 + 101| 350 + 110| failed probe + 111| 3E0 + + SW 2 : Node ID (binary coded) + + JP 4 : Boot PROM enable CLOSE - enabled + OPEN - disabled + + JP 6 : IRQ set (ONLY ONE jumper on 1-5 for IRQ 2-6) + + +Acer +==== + +8-bit card, Model 5210-003 +-------------------------- + + - from Vojtech Pavlik <vojtech@suse.cz> using portions of the existing + arcnet-hardware file. + +This is a 90C26 based card. Its configuration seems similar to the SMC +PC100, but has some additional jumpers I don't know the meaning of. + +:: + + __ + | | + ___________|__|_________________________ + | | | | + | | BNC | | + | |______| ___| + | _____________________ |___ + | | | | + | | Hybrid IC | | + | | | o|o J1 | + | |_____________________| 8|8 | + | 8|8 J5 | + | o|o | + | 8|8 | + |__ 8|8 | + (|__| LED o|o | + | 8|8 | + | 8|8 J15 | + | | + | _____ | + | | | _____ | + | | | | | ___| + | | | | | | + | _____ | ROM | | UFS | | + | | | | | | | | + | | | ___ | | | | | + | | | | | |__.__| |__.__| | + | | NCR | |XTL| _____ _____ | + | | | |___| | | | | | + | |90C26| | | | | | + | | | | RAM | | UFS | | + | | | J17 o|o | | | | | + | | | J16 o|o | | | | | + | |__.__| |__.__| |__.__| | + | ___ | + | | |8 | + | |SW2| | + | | | | + | |___|1 | + | ___ | + | | |10 J18 o|o | + | | | o|o | + | |SW1| o|o | + | | | J21 o|o | + | |___|1 | + | | + |____________________________________| + + +Legend:: + + 90C26 ARCNET Chip + XTL 20 MHz Crystal + SW1 1-6 Base I/O Address Select + 7-10 Memory Address Select + SW2 1-8 Node ID Select (ID0-ID7) + J1-J5 IRQ Select + J6-J21 Unknown (Probably extra timeouts & ROM enable ...) + LED1 Activity LED + BNC Coax connector (STAR ARCnet) + RAM 2k of SRAM + ROM Boot ROM socket + UFS Unidentified Flying Sockets + + +Setting the Node ID +^^^^^^^^^^^^^^^^^^^ + +The eight switches in SW2 are used to set the node ID. Each node attached +to the network must have an unique node ID which must not be 0. +Switch 1 (ID0) serves as the least significant bit (LSB). + +Setting one of the switches to OFF means "1", ON means "0". + +The node ID is the sum of the values of all switches set to "1" +These values are:: + + Switch | Value + -------|------- + 1 | 1 + 2 | 2 + 3 | 4 + 4 | 8 + 5 | 16 + 6 | 32 + 7 | 64 + 8 | 128 + +Don't set this to 0 or 255; these values are reserved. + + +Setting the I/O Base Address +^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The switches 1 to 6 of switch block SW1 are used to select one +of 32 possible I/O Base addresses using the following tables:: + + | Hex + Switch | Value + -------|------- + 1 | 200 + 2 | 100 + 3 | 80 + 4 | 40 + 5 | 20 + 6 | 10 + +The I/O address is sum of all switches set to "1". Remember that +the I/O address space below 0x200 is RESERVED for mainboard, so +switch 1 should be ALWAYS SET TO OFF. + + +Setting the Base Memory (RAM) buffer Address +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The memory buffer (RAM) requires 2K. The base of this buffer can be +located in any of sixteen positions. However, the addresses below +A0000 are likely to cause system hang because there's main RAM. + +Jumpers 7-10 of switch block SW1 select the Memory Base address:: + + Switch | Hex RAM + 7 8 9 10 | Address + ----------------|--------- + OFF OFF OFF OFF | F0000 (conflicts with main BIOS) + OFF OFF OFF ON | E0000 + OFF OFF ON OFF | D0000 + OFF OFF ON ON | C0000 (conflicts with video BIOS) + OFF ON OFF OFF | B0000 (conflicts with mono video) + OFF ON OFF ON | A0000 (conflicts with graphics) + + +Setting the Interrupt Line +^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Jumpers 1-5 of the jumper block J1 control the IRQ level. ON means +shorted, OFF means open:: + + Jumper | IRQ + 1 2 3 4 5 | + ---------------------------- + ON OFF OFF OFF OFF | 7 + OFF ON OFF OFF OFF | 5 + OFF OFF ON OFF OFF | 4 + OFF OFF OFF ON OFF | 3 + OFF OFF OFF OFF ON | 2 + + +Unknown jumpers & sockets +^^^^^^^^^^^^^^^^^^^^^^^^^ + +I know nothing about these. I just guess that J16&J17 are timeout +jumpers and maybe one of J18-J21 selects ROM. Also J6-J10 and +J11-J15 are connecting IRQ2-7 to some pins on the UFSs. I can't +guess the purpose. + +Datapoint? +========== + +LAN-ARC-8, an 8-bit card +------------------------ + + - from Vojtech Pavlik <vojtech@suse.cz> + +This is another SMC 90C65-based ARCnet card. I couldn't identify the +manufacturer, but it might be DataPoint, because the card has the +original arcNet logo in its upper right corner. + +:: + + _______________________________________________________ + | _________ | + | | SW2 | ON arcNet | + | |_________| OFF ___| + | _____________ 1 ______ 8 | | 8 + | | | SW1 | XTAL | ____________ | S | + | > RAM (2k) | |______|| | | W | + | |_____________| | H | | 3 | + | _________|_____ y | |___| 1 + | _________ | | |b | | + | |_________| | | |r | | + | | SMC | |i | | + | | 90C65| |d | | + | _________ | | | | | + | | SW1 | ON | | |I | | + | |_________| OFF |_________|_____/C | _____| + | 1 8 | | | |___ + | ______________ | | | BNC |___| + | | | |____________| |_____| + | > EPROM SOCKET | _____________ | + | |______________| |_____________| | + | ______________| + | | + |________________________________________| + +Legend:: + + 90C65 ARCNET Chip + SW1 1-5: Base Memory Address Select + 6-8: Base I/O Address Select + SW2 1-8: Node ID Select + SW3 1-5: IRQ Select + 6-7: Extra Timeout + 8 : ROM Enable + BNC Coax connector + XTAL 20 MHz Crystal + + +Setting the Node ID +^^^^^^^^^^^^^^^^^^^ + +The eight switches in SW3 are used to set the node ID. Each node attached +to the network must have an unique node ID which must not be 0. +Switch 1 serves as the least significant bit (LSB). + +Setting one of the switches to Off means "1", On means "0". + +The node ID is the sum of the values of all switches set to "1" +These values are:: + + Switch | Value + -------|------- + 1 | 1 + 2 | 2 + 3 | 4 + 4 | 8 + 5 | 16 + 6 | 32 + 7 | 64 + 8 | 128 + + +Setting the I/O Base Address +^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The last three switches in switch block SW1 are used to select one +of eight possible I/O Base addresses using the following table:: + + + Switch | Hex I/O + 6 7 8 | Address + ------------|-------- + ON ON ON | 260 + OFF ON ON | 290 + ON OFF ON | 2E0 (Manufacturer's default) + OFF OFF ON | 2F0 + ON ON OFF | 300 + OFF ON OFF | 350 + ON OFF OFF | 380 + OFF OFF OFF | 3E0 + + +Setting the Base Memory (RAM) buffer Address +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The memory buffer (RAM) requires 2K. The base of this buffer can be +located in any of eight positions. The address of the Boot Prom is +memory base + 0x2000. + +Jumpers 3-5 of switch block SW1 select the Memory Base address. + +:: + + Switch | Hex RAM | Hex ROM + 1 2 3 4 5 | Address | Address *) + --------------------|---------|----------- + ON ON ON ON ON | C0000 | C2000 + ON ON OFF ON ON | C4000 | C6000 + ON ON ON OFF ON | CC000 | CE000 + ON ON OFF OFF ON | D0000 | D2000 (Manufacturer's default) + ON ON ON ON OFF | D4000 | D6000 + ON ON OFF ON OFF | D8000 | DA000 + ON ON ON OFF OFF | DC000 | DE000 + ON ON OFF OFF OFF | E0000 | E2000 + + *) To enable the Boot ROM set the switch 8 of switch block SW3 to position ON. + +The switches 1 and 2 probably add 0x0800 and 0x1000 to RAM base address. + + +Setting the Interrupt Line +^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Switches 1-5 of the switch block SW3 control the IRQ level:: + + Jumper | IRQ + 1 2 3 4 5 | + ---------------------------- + ON OFF OFF OFF OFF | 3 + OFF ON OFF OFF OFF | 4 + OFF OFF ON OFF OFF | 5 + OFF OFF OFF ON OFF | 7 + OFF OFF OFF OFF ON | 2 + + +Setting the Timeout Parameters +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The switches 6-7 of the switch block SW3 are used to determine the timeout +parameters. These two switches are normally left in the OFF position. + + +Topware +======= + +8-bit card, TA-ARC/10 +--------------------- + + - from Vojtech Pavlik <vojtech@suse.cz> + +This is another very similar 90C65 card. Most of the switches and jumpers +are the same as on other clones. + +:: + + _____________________________________________________________________ + | ___________ | | ______ | + | |SW2 NODE ID| | | | XTAL | | + | |___________| | Hybrid IC | |______| | + | ___________ | | __| + | |SW1 MEM+I/O| |_________________________| LED1|__|) + | |___________| 1 2 | + | J3 |o|o| TIMEOUT ______| + | ______________ |o|o| | | + | | | ___________________ | RJ | + | > EPROM SOCKET | | \ |------| + |J2 |______________| | | | | + ||o| | | |______| + ||o| ROM ENABLE | SMC | _________ | + | _____________ | 90C65 | |_________| _____| + | | | | | | |___ + | > RAM (2k) | | | | BNC |___| + | |_____________| | | |_____| + | |____________________| | + | ________ IRQ 2 3 4 5 7 ___________ | + ||________| |o|o|o|o|o| |___________| | + |________ J1|o|o|o|o|o| ______________| + | | + |_____________________________________________| + +Legend:: + + 90C65 ARCNET Chip + XTAL 20 MHz Crystal + SW1 1-5 Base Memory Address Select + 6-8 Base I/O Address Select + SW2 1-8 Node ID Select (ID0-ID7) + J1 IRQ Select + J2 ROM Enable + J3 Extra Timeout + LED1 Activity LED + BNC Coax connector (BUS ARCnet) + RJ Twisted Pair Connector (daisy chain) + + +Setting the Node ID +^^^^^^^^^^^^^^^^^^^ + +The eight switches in SW2 are used to set the node ID. Each node attached to +the network must have an unique node ID which must not be 0. Switch 1 (ID0) +serves as the least significant bit (LSB). + +Setting one of the switches to Off means "1", On means "0". + +The node ID is the sum of the values of all switches set to "1" +These values are:: + + Switch | Label | Value + -------|-------|------- + 1 | ID0 | 1 + 2 | ID1 | 2 + 3 | ID2 | 4 + 4 | ID3 | 8 + 5 | ID4 | 16 + 6 | ID5 | 32 + 7 | ID6 | 64 + 8 | ID7 | 128 + +Setting the I/O Base Address +^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The last three switches in switch block SW1 are used to select one +of eight possible I/O Base addresses using the following table:: + + + Switch | Hex I/O + 6 7 8 | Address + ------------|-------- + ON ON ON | 260 (Manufacturer's default) + OFF ON ON | 290 + ON OFF ON | 2E0 + OFF OFF ON | 2F0 + ON ON OFF | 300 + OFF ON OFF | 350 + ON OFF OFF | 380 + OFF OFF OFF | 3E0 + + +Setting the Base Memory (RAM) buffer Address +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The memory buffer (RAM) requires 2K. The base of this buffer can be +located in any of eight positions. The address of the Boot Prom is +memory base + 0x2000. + +Jumpers 3-5 of switch block SW1 select the Memory Base address. + +:: + + Switch | Hex RAM | Hex ROM + 1 2 3 4 5 | Address | Address *) + --------------------|---------|----------- + ON ON ON ON ON | C0000 | C2000 + ON ON OFF ON ON | C4000 | C6000 (Manufacturer's default) + ON ON ON OFF ON | CC000 | CE000 + ON ON OFF OFF ON | D0000 | D2000 + ON ON ON ON OFF | D4000 | D6000 + ON ON OFF ON OFF | D8000 | DA000 + ON ON ON OFF OFF | DC000 | DE000 + ON ON OFF OFF OFF | E0000 | E2000 + + *) To enable the Boot ROM short the jumper J2. + +The jumpers 1 and 2 probably add 0x0800 and 0x1000 to RAM address. + + +Setting the Interrupt Line +^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Jumpers 1-5 of the jumper block J1 control the IRQ level. ON means +shorted, OFF means open:: + + Jumper | IRQ + 1 2 3 4 5 | + ---------------------------- + ON OFF OFF OFF OFF | 2 + OFF ON OFF OFF OFF | 3 + OFF OFF ON OFF OFF | 4 + OFF OFF OFF ON OFF | 5 + OFF OFF OFF OFF ON | 7 + + +Setting the Timeout Parameters +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The jumpers J3 are used to set the timeout parameters. These two +jumpers are normally left open. + +Thomas-Conrad +============= + +Model #500-6242-0097 REV A (8-bit card) +--------------------------------------- + + - from Lars Karlsson <100617.3473@compuserve.com> + +:: + + ________________________________________________________ + | ________ ________ |_____ + | |........| |........| | + | |________| |________| ___| + | SW 3 SW 1 | | + | Base I/O Base Addr. Station | | + | address | | + | ______ switch | | + | | | | | + | | | |___| + | | | ______ |___._ + | |______| |______| ____| BNC + | Jumper- _____| Connector + | Main chip block _ __| ' + | | | | RJ Connector + | |_| | with 110 Ohm + | |__ Terminator + | ___________ __| + | |...........| | RJ-jack + | |...........| _____ | (unused) + | |___________| |_____| |__ + | Boot PROM socket IRQ-jumpers |_ Diagnostic + |________ __ _| LED (red) + | | | | | | | | | | | | | | | | | | | | | | + | | | | | | | | | | | | | | | | | | | | |________| + | + | + +And here are the settings for some of the switches and jumpers on the cards. + +:: + + I/O + + 1 2 3 4 5 6 7 8 + + 2E0----- 0 0 0 1 0 0 0 1 + 2F0----- 0 0 0 1 0 0 0 0 + 300----- 0 0 0 0 1 1 1 1 + 350----- 0 0 0 0 1 1 1 0 + +"0" in the above example means switch is off "1" means that it is on. + +:: + + ShMem address. + + 1 2 3 4 5 6 7 8 + + CX00--0 0 1 1 | | | + DX00--0 0 1 0 | + X000--------- 1 1 | + X400--------- 1 0 | + X800--------- 0 1 | + XC00--------- 0 0 + ENHANCED----------- 1 + COMPATIBLE--------- 0 + +:: + + IRQ + + + 3 4 5 7 2 + . . . . . + . . . . . + + +There is a DIP-switch with 8 switches, used to set the shared memory address +to be used. The first 6 switches set the address, the 7th doesn't have any +function, and the 8th switch is used to select "compatible" or "enhanced". +When I got my two cards, one of them had this switch set to "enhanced". That +card didn't work at all, it wasn't even recognized by the driver. The other +card had this switch set to "compatible" and it behaved absolutely normally. I +guess that the switch on one of the cards, must have been changed accidentally +when the card was taken out of its former host. The question remains +unanswered, what is the purpose of the "enhanced" position? + +[Avery's note: "enhanced" probably either disables shared memory (use IO +ports instead) or disables IO ports (use memory addresses instead). This +varies by the type of card involved. I fail to see how either of these +enhance anything. Send me more detailed information about this mode, or +just use "compatible" mode instead.] + +Waterloo Microsystems Inc. ?? +============================= + +8-bit card (C) 1985 +------------------- + - from Robert Michael Best <rmb117@cs.usask.ca> + +[Avery's note: these don't work with my driver for some reason. These cards +SEEM to have settings similar to the PDI508Plus, which is +software-configured and doesn't work with my driver either. The "Waterloo +chip" is a boot PROM, probably designed specifically for the University of +Waterloo. If you have any further information about this card, please +e-mail me.] + +The probe has not been able to detect the card on any of the J2 settings, +and I tried them again with the "Waterloo" chip removed. + +:: + + _____________________________________________________________________ + | \/ \/ ___ __ __ | + | C4 C4 |^| | M || ^ ||^| | + | -- -- |_| | 5 || || | C3 | + | \/ \/ C10 |___|| ||_| | + | C4 C4 _ _ | | ?? | + | -- -- | \/ || | | + | | || | | + | | || C1 | | + | | || | \/ _____| + | | C6 || | C9 | |___ + | | || | -- | BNC |___| + | | || | >C7| |_____| + | | || | | + | __ __ |____||_____| 1 2 3 6 | + || ^ | >C4| |o|o|o|o|o|o| J2 >C4| | + || | |o|o|o|o|o|o| | + || C2 | >C4| >C4| | + || | >C8| | + || | 2 3 4 5 6 7 IRQ >C4| | + ||_____| |o|o|o|o|o|o| J3 | + |_______ |o|o|o|o|o|o| _______________| + | | + |_____________________________________________| + + C1 -- "COM9026 + SMC 8638" + In a chip socket. + + C2 -- "@Copyright + Waterloo Microsystems Inc. + 1985" + In a chip Socket with info printed on a label covering a round window + showing the circuit inside. (The window indicates it is an EPROM chip.) + + C3 -- "COM9032 + SMC 8643" + In a chip socket. + + C4 -- "74LS" + 9 total no sockets. + + M5 -- "50006-136 + 20.000000 MHZ + MTQ-T1-S3 + 0 M-TRON 86-40" + Metallic case with 4 pins, no socket. + + C6 -- "MOSTEK@TC8643 + MK6116N-20 + MALAYSIA" + No socket. + + C7 -- No stamp or label but in a 20 pin chip socket. + + C8 -- "PAL10L8CN + 8623" + In a 20 pin socket. + + C9 -- "PAl16R4A-2CN + 8641" + In a 20 pin socket. + + C10 -- "M8640 + NMC + 9306N" + In an 8 pin socket. + + ?? -- Some components on a smaller board and attached with 20 pins all + along the side closest to the BNC connector. The are coated in a dark + resin. + +On the board there are two jumper banks labeled J2 and J3. The +manufacturer didn't put a J1 on the board. The two boards I have both +came with a jumper box for each bank. + +:: + + J2 -- Numbered 1 2 3 4 5 6. + 4 and 5 are not stamped due to solder points. + + J3 -- IRQ 2 3 4 5 6 7 + +The board itself has a maple leaf stamped just above the irq jumpers +and "-2 46-86" beside C2. Between C1 and C6 "ASS 'Y 300163" and "@1986 +CORMAN CUSTOM ELECTRONICS CORP." stamped just below the BNC connector. +Below that "MADE IN CANADA" + +No Name +======= + +8-bit cards, 16-bit cards +------------------------- + + - from Juergen Seifert <seifert@htwm.de> + +I have named this ARCnet card "NONAME", since there is no name of any +manufacturer on the Installation manual nor on the shipping box. The only +hint to the existence of a manufacturer at all is written in copper, +it is "Made in Taiwan" + +This description has been written by Juergen Seifert <seifert@htwm.de> +using information from the Original + + "ARCnet Installation Manual" + +:: + + ________________________________________________________________ + | |STAR| BUS| T/P| | + | |____|____|____| | + | _____________________ | + | | | | + | | | | + | | | | + | | SMC | | + | | | | + | | COM90C65 | | + | | | | + | | | | + | |__________-__________| | + | _____| + | _______________ | CN | + | | PROM | |_____| + | > SOCKET | | + | |_______________| 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 | + | _______________ _______________ | + | |o|o|o|o|o|o|o|o| | SW1 || SW2 || + | |o|o|o|o|o|o|o|o| |_______________||_______________|| + |___ 2 3 4 5 7 E E R Node ID IOB__|__MEM____| + | \ IRQ / T T O | + |__________________1_2_M______________________| + +Legend:: + + COM90C65: ARCnet Probe + S1 1-8: Node ID Select + S2 1-3: I/O Base Address Select + 4-6: Memory Base Address Select + 7-8: RAM Offset Select + ET1, ET2 Extended Timeout Select + ROM ROM Enable Select + CN RG62 Coax Connector + STAR| BUS | T/P Three fields for placing a sign (colored circle) + indicating the topology of the card + +Setting one of the switches to Off means "1", On means "0". + + +Setting the Node ID +^^^^^^^^^^^^^^^^^^^ + +The eight switches in group SW1 are used to set the node ID. +Each node attached to the network must have an unique node ID which +must be different from 0. +Switch 8 serves as the least significant bit (LSB). + +The node ID is the sum of the values of all switches set to "1" +These values are:: + + Switch | Value + -------|------- + 8 | 1 + 7 | 2 + 6 | 4 + 5 | 8 + 4 | 16 + 3 | 32 + 2 | 64 + 1 | 128 + +Some Examples:: + + Switch | Hex | Decimal + 1 2 3 4 5 6 7 8 | Node ID | Node ID + ----------------|---------|--------- + 0 0 0 0 0 0 0 0 | not allowed + 0 0 0 0 0 0 0 1 | 1 | 1 + 0 0 0 0 0 0 1 0 | 2 | 2 + 0 0 0 0 0 0 1 1 | 3 | 3 + . . . | | + 0 1 0 1 0 1 0 1 | 55 | 85 + . . . | | + 1 0 1 0 1 0 1 0 | AA | 170 + . . . | | + 1 1 1 1 1 1 0 1 | FD | 253 + 1 1 1 1 1 1 1 0 | FE | 254 + 1 1 1 1 1 1 1 1 | FF | 255 + + +Setting the I/O Base Address +^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The first three switches in switch group SW2 are used to select one +of eight possible I/O Base addresses using the following table:: + + Switch | Hex I/O + 1 2 3 | Address + ------------|-------- + ON ON ON | 260 + ON ON OFF | 290 + ON OFF ON | 2E0 (Manufacturer's default) + ON OFF OFF | 2F0 + OFF ON ON | 300 + OFF ON OFF | 350 + OFF OFF ON | 380 + OFF OFF OFF | 3E0 + + +Setting the Base Memory (RAM) buffer Address +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The memory buffer requires 2K of a 16K block of RAM. The base of this +16K block can be located in any of eight positions. +Switches 4-6 of switch group SW2 select the Base of the 16K block. +Within that 16K address space, the buffer may be assigned any one of four +positions, determined by the offset, switches 7 and 8 of group SW2. + +:: + + Switch | Hex RAM | Hex ROM + 4 5 6 7 8 | Address | Address *) + -----------|---------|----------- + 0 0 0 0 0 | C0000 | C2000 + 0 0 0 0 1 | C0800 | C2000 + 0 0 0 1 0 | C1000 | C2000 + 0 0 0 1 1 | C1800 | C2000 + | | + 0 0 1 0 0 | C4000 | C6000 + 0 0 1 0 1 | C4800 | C6000 + 0 0 1 1 0 | C5000 | C6000 + 0 0 1 1 1 | C5800 | C6000 + | | + 0 1 0 0 0 | CC000 | CE000 + 0 1 0 0 1 | CC800 | CE000 + 0 1 0 1 0 | CD000 | CE000 + 0 1 0 1 1 | CD800 | CE000 + | | + 0 1 1 0 0 | D0000 | D2000 (Manufacturer's default) + 0 1 1 0 1 | D0800 | D2000 + 0 1 1 1 0 | D1000 | D2000 + 0 1 1 1 1 | D1800 | D2000 + | | + 1 0 0 0 0 | D4000 | D6000 + 1 0 0 0 1 | D4800 | D6000 + 1 0 0 1 0 | D5000 | D6000 + 1 0 0 1 1 | D5800 | D6000 + | | + 1 0 1 0 0 | D8000 | DA000 + 1 0 1 0 1 | D8800 | DA000 + 1 0 1 1 0 | D9000 | DA000 + 1 0 1 1 1 | D9800 | DA000 + | | + 1 1 0 0 0 | DC000 | DE000 + 1 1 0 0 1 | DC800 | DE000 + 1 1 0 1 0 | DD000 | DE000 + 1 1 0 1 1 | DD800 | DE000 + | | + 1 1 1 0 0 | E0000 | E2000 + 1 1 1 0 1 | E0800 | E2000 + 1 1 1 1 0 | E1000 | E2000 + 1 1 1 1 1 | E1800 | E2000 + + *) To enable the 8K Boot PROM install the jumper ROM. + The default is jumper ROM not installed. + + +Setting Interrupt Request Lines (IRQ) +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +To select a hardware interrupt level set one (only one!) of the jumpers +IRQ2, IRQ3, IRQ4, IRQ5 or IRQ7. The manufacturer's default is IRQ2. + + +Setting the Timeouts +^^^^^^^^^^^^^^^^^^^^ + +The two jumpers labeled ET1 and ET2 are used to determine the timeout +parameters (response and reconfiguration time). Every node in a network +must be set to the same timeout values. + +:: + + ET1 ET2 | Response Time (us) | Reconfiguration Time (ms) + --------|--------------------|-------------------------- + Off Off | 78 | 840 (Default) + Off On | 285 | 1680 + On Off | 563 | 1680 + On On | 1130 | 1680 + +On means jumper installed, Off means jumper not installed + + +16-BIT ARCNET +------------- + +The manual of my 8-Bit NONAME ARCnet Card contains another description +of a 16-Bit Coax / Twisted Pair Card. This description is incomplete, +because there are missing two pages in the manual booklet. (The table +of contents reports pages ... 2-9, 2-11, 2-12, 3-1, ... but inside +the booklet there is a different way of counting ... 2-9, 2-10, A-1, +(empty page), 3-1, ..., 3-18, A-1 (again), A-2) +Also the picture of the board layout is not as good as the picture of +8-Bit card, because there isn't any letter like "SW1" written to the +picture. + +Should somebody have such a board, please feel free to complete this +description or to send a mail to me! + +This description has been written by Juergen Seifert <seifert@htwm.de> +using information from the Original + + "ARCnet Installation Manual" + +:: + + ___________________________________________________________________ + < _________________ _________________ | + > | SW? || SW? | | + < |_________________||_________________| | + > ____________________ | + < | | | + > | | | + < | | | + > | | | + < | | | + > | | | + < | | | + > |____________________| | + < ____| + > ____________________ | | + < | | | J1 | + > | < | | + < |____________________| ? ? ? ? ? ? |____| + > |o|o|o|o|o|o| | + < |o|o|o|o|o|o| | + > | + < __ ___________| + > | | | + <____________| |_______________________________________| + + +Setting one of the switches to Off means "1", On means "0". + + +Setting the Node ID +^^^^^^^^^^^^^^^^^^^ + +The eight switches in group SW2 are used to set the node ID. +Each node attached to the network must have an unique node ID which +must be different from 0. +Switch 8 serves as the least significant bit (LSB). + +The node ID is the sum of the values of all switches set to "1" +These values are:: + + Switch | Value + -------|------- + 8 | 1 + 7 | 2 + 6 | 4 + 5 | 8 + 4 | 16 + 3 | 32 + 2 | 64 + 1 | 128 + +Some Examples:: + + Switch | Hex | Decimal + 1 2 3 4 5 6 7 8 | Node ID | Node ID + ----------------|---------|--------- + 0 0 0 0 0 0 0 0 | not allowed + 0 0 0 0 0 0 0 1 | 1 | 1 + 0 0 0 0 0 0 1 0 | 2 | 2 + 0 0 0 0 0 0 1 1 | 3 | 3 + . . . | | + 0 1 0 1 0 1 0 1 | 55 | 85 + . . . | | + 1 0 1 0 1 0 1 0 | AA | 170 + . . . | | + 1 1 1 1 1 1 0 1 | FD | 253 + 1 1 1 1 1 1 1 0 | FE | 254 + 1 1 1 1 1 1 1 1 | FF | 255 + + +Setting the I/O Base Address +^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The first three switches in switch group SW1 are used to select one +of eight possible I/O Base addresses using the following table:: + + Switch | Hex I/O + 3 2 1 | Address + ------------|-------- + ON ON ON | 260 + ON ON OFF | 290 + ON OFF ON | 2E0 (Manufacturer's default) + ON OFF OFF | 2F0 + OFF ON ON | 300 + OFF ON OFF | 350 + OFF OFF ON | 380 + OFF OFF OFF | 3E0 + + +Setting the Base Memory (RAM) buffer Address +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The memory buffer requires 2K of a 16K block of RAM. The base of this +16K block can be located in any of eight positions. +Switches 6-8 of switch group SW1 select the Base of the 16K block. +Within that 16K address space, the buffer may be assigned any one of four +positions, determined by the offset, switches 4 and 5 of group SW1:: + + Switch | Hex RAM | Hex ROM + 8 7 6 5 4 | Address | Address + -----------|---------|----------- + 0 0 0 0 0 | C0000 | C2000 + 0 0 0 0 1 | C0800 | C2000 + 0 0 0 1 0 | C1000 | C2000 + 0 0 0 1 1 | C1800 | C2000 + | | + 0 0 1 0 0 | C4000 | C6000 + 0 0 1 0 1 | C4800 | C6000 + 0 0 1 1 0 | C5000 | C6000 + 0 0 1 1 1 | C5800 | C6000 + | | + 0 1 0 0 0 | CC000 | CE000 + 0 1 0 0 1 | CC800 | CE000 + 0 1 0 1 0 | CD000 | CE000 + 0 1 0 1 1 | CD800 | CE000 + | | + 0 1 1 0 0 | D0000 | D2000 (Manufacturer's default) + 0 1 1 0 1 | D0800 | D2000 + 0 1 1 1 0 | D1000 | D2000 + 0 1 1 1 1 | D1800 | D2000 + | | + 1 0 0 0 0 | D4000 | D6000 + 1 0 0 0 1 | D4800 | D6000 + 1 0 0 1 0 | D5000 | D6000 + 1 0 0 1 1 | D5800 | D6000 + | | + 1 0 1 0 0 | D8000 | DA000 + 1 0 1 0 1 | D8800 | DA000 + 1 0 1 1 0 | D9000 | DA000 + 1 0 1 1 1 | D9800 | DA000 + | | + 1 1 0 0 0 | DC000 | DE000 + 1 1 0 0 1 | DC800 | DE000 + 1 1 0 1 0 | DD000 | DE000 + 1 1 0 1 1 | DD800 | DE000 + | | + 1 1 1 0 0 | E0000 | E2000 + 1 1 1 0 1 | E0800 | E2000 + 1 1 1 1 0 | E1000 | E2000 + 1 1 1 1 1 | E1800 | E2000 + + +Setting Interrupt Request Lines (IRQ) +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +?????????????????????????????????????? + + +Setting the Timeouts +^^^^^^^^^^^^^^^^^^^^ + +?????????????????????????????????????? + + +8-bit cards ("Made in Taiwan R.O.C.") +------------------------------------- + + - from Vojtech Pavlik <vojtech@suse.cz> + +I have named this ARCnet card "NONAME", since I got only the card with +no manual at all and the only text identifying the manufacturer is +"MADE IN TAIWAN R.O.C" printed on the card. + +:: + + ____________________________________________________________ + | 1 2 3 4 5 6 7 8 | + | |o|o| JP1 o|o|o|o|o|o|o|o| ON | + | + o|o|o|o|o|o|o|o| ___| + | _____________ o|o|o|o|o|o|o|o| OFF _____ | | ID7 + | | | SW1 | | | | ID6 + | > RAM (2k) | ____________________ | H | | S | ID5 + | |_____________| | || y | | W | ID4 + | | || b | | 2 | ID3 + | | || r | | | ID2 + | | || i | | | ID1 + | | 90C65 || d | |___| ID0 + | SW3 | || | | + | |o|o|o|o|o|o|o|o| ON | || I | | + | |o|o|o|o|o|o|o|o| | || C | | + | |o|o|o|o|o|o|o|o| OFF |____________________|| | _____| + | 1 2 3 4 5 6 7 8 | | | |___ + | ______________ | | | BNC |___| + | | | |_____| |_____| + | > EPROM SOCKET | | + | |______________| | + | ______________| + | | + |_____________________________________________| + +Legend:: + + 90C65 ARCNET Chip + SW1 1-5: Base Memory Address Select + 6-8: Base I/O Address Select + SW2 1-8: Node ID Select (ID0-ID7) + SW3 1-5: IRQ Select + 6-7: Extra Timeout + 8 : ROM Enable + JP1 Led connector + BNC Coax connector + +Although the jumpers SW1 and SW3 are marked SW, not JP, they are jumpers, not +switches. + +Setting the jumpers to ON means connecting the upper two pins, off the bottom +two - or - in case of IRQ setting, connecting none of them at all. + +Setting the Node ID +^^^^^^^^^^^^^^^^^^^ + +The eight switches in SW2 are used to set the node ID. Each node attached +to the network must have an unique node ID which must not be 0. +Switch 1 (ID0) serves as the least significant bit (LSB). + +Setting one of the switches to Off means "1", On means "0". + +The node ID is the sum of the values of all switches set to "1" +These values are:: + + Switch | Label | Value + -------|-------|------- + 1 | ID0 | 1 + 2 | ID1 | 2 + 3 | ID2 | 4 + 4 | ID3 | 8 + 5 | ID4 | 16 + 6 | ID5 | 32 + 7 | ID6 | 64 + 8 | ID7 | 128 + +Some Examples:: + + Switch | Hex | Decimal + 8 7 6 5 4 3 2 1 | Node ID | Node ID + ----------------|---------|--------- + 0 0 0 0 0 0 0 0 | not allowed + 0 0 0 0 0 0 0 1 | 1 | 1 + 0 0 0 0 0 0 1 0 | 2 | 2 + 0 0 0 0 0 0 1 1 | 3 | 3 + . . . | | + 0 1 0 1 0 1 0 1 | 55 | 85 + . . . | | + 1 0 1 0 1 0 1 0 | AA | 170 + . . . | | + 1 1 1 1 1 1 0 1 | FD | 253 + 1 1 1 1 1 1 1 0 | FE | 254 + 1 1 1 1 1 1 1 1 | FF | 255 + + +Setting the I/O Base Address +^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The last three switches in switch block SW1 are used to select one +of eight possible I/O Base addresses using the following table:: + + + Switch | Hex I/O + 6 7 8 | Address + ------------|-------- + ON ON ON | 260 + OFF ON ON | 290 + ON OFF ON | 2E0 (Manufacturer's default) + OFF OFF ON | 2F0 + ON ON OFF | 300 + OFF ON OFF | 350 + ON OFF OFF | 380 + OFF OFF OFF | 3E0 + + +Setting the Base Memory (RAM) buffer Address +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The memory buffer (RAM) requires 2K. The base of this buffer can be +located in any of eight positions. The address of the Boot Prom is +memory base + 0x2000. + +Jumpers 3-5 of jumper block SW1 select the Memory Base address. + +:: + + Switch | Hex RAM | Hex ROM + 1 2 3 4 5 | Address | Address *) + --------------------|---------|----------- + ON ON ON ON ON | C0000 | C2000 + ON ON OFF ON ON | C4000 | C6000 + ON ON ON OFF ON | CC000 | CE000 + ON ON OFF OFF ON | D0000 | D2000 (Manufacturer's default) + ON ON ON ON OFF | D4000 | D6000 + ON ON OFF ON OFF | D8000 | DA000 + ON ON ON OFF OFF | DC000 | DE000 + ON ON OFF OFF OFF | E0000 | E2000 + + *) To enable the Boot ROM set the jumper 8 of jumper block SW3 to position ON. + +The jumpers 1 and 2 probably add 0x0800, 0x1000 and 0x1800 to RAM adders. + +Setting the Interrupt Line +^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Jumpers 1-5 of the jumper block SW3 control the IRQ level:: + + Jumper | IRQ + 1 2 3 4 5 | + ---------------------------- + ON OFF OFF OFF OFF | 2 + OFF ON OFF OFF OFF | 3 + OFF OFF ON OFF OFF | 4 + OFF OFF OFF ON OFF | 5 + OFF OFF OFF OFF ON | 7 + + +Setting the Timeout Parameters +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The jumpers 6-7 of the jumper block SW3 are used to determine the timeout +parameters. These two jumpers are normally left in the OFF position. + + + +(Generic Model 9058) +-------------------- + - from Andrew J. Kroll <ag784@freenet.buffalo.edu> + - Sorry this sat in my to-do box for so long, Andrew! (yikes - over a + year!) + +:: + + _____ + | < + | .---' + ________________________________________________________________ | | + | | SW2 | | | + | ___________ |_____________| | | + | | | 1 2 3 4 5 6 ___| | + | > 6116 RAM | _________ 8 | | | + | |___________| |20MHzXtal| 7 | | | + | |_________| __________ 6 | S | | + | 74LS373 | |- 5 | W | | + | _________ | E |- 4 | | | + | >_______| ______________|..... P |- 3 | 3 | | + | | | : O |- 2 | | | + | | | : X |- 1 |___| | + | ________________ | | : Y |- | | + | | SW1 | | SL90C65 | : |- | | + | |________________| | | : B |- | | + | 1 2 3 4 5 6 7 8 | | : O |- | | + | |_________o____|..../ A |- _______| | + | ____________________ | R |- | |------, + | | | | D |- | BNC | # | + | > 2764 PROM SOCKET | |__________|- |_______|------' + | |____________________| _________ | | + | >________| <- 74LS245 | | + | | | + |___ ______________| | + |H H H H H H H H H H H H H H H H H H H H H H H| | | + |U_U_U_U_U_U_U_U_U_U_U_U_U_U_U_U_U_U_U_U_U_U_U| | | + \| + +Legend:: + + SL90C65 ARCNET Controller / Transceiver /Logic + SW1 1-5: IRQ Select + 6: ET1 + 7: ET2 + 8: ROM ENABLE + SW2 1-3: Memory Buffer/PROM Address + 3-6: I/O Address Map + SW3 1-8: Node ID Select + BNC BNC RG62/U Connection + *I* have had success using RG59B/U with *NO* terminators! + What gives?! + +SW1: Timeouts, Interrupt and ROM +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +To select a hardware interrupt level set one (only one!) of the dip switches +up (on) SW1...(switches 1-5) +IRQ3, IRQ4, IRQ5, IRQ7, IRQ2. The Manufacturer's default is IRQ2. + +The switches on SW1 labeled EXT1 (switch 6) and EXT2 (switch 7) +are used to determine the timeout parameters. These two dip switches +are normally left off (down). + + To enable the 8K Boot PROM position SW1 switch 8 on (UP) labeled ROM. + The default is jumper ROM not installed. + + +Setting the I/O Base Address +^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The last three switches in switch group SW2 are used to select one +of eight possible I/O Base addresses using the following table:: + + + Switch | Hex I/O + 4 5 6 | Address + -------|-------- + 0 0 0 | 260 + 0 0 1 | 290 + 0 1 0 | 2E0 (Manufacturer's default) + 0 1 1 | 2F0 + 1 0 0 | 300 + 1 0 1 | 350 + 1 1 0 | 380 + 1 1 1 | 3E0 + + +Setting the Base Memory Address (RAM & ROM) +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The memory buffer requires 2K of a 16K block of RAM. The base of this +16K block can be located in any of eight positions. +Switches 1-3 of switch group SW2 select the Base of the 16K block. +(0 = DOWN, 1 = UP) +I could, however, only verify two settings... + + +:: + + Switch| Hex RAM | Hex ROM + 1 2 3 | Address | Address + ------|---------|----------- + 0 0 0 | E0000 | E2000 + 0 0 1 | D0000 | D2000 (Manufacturer's default) + 0 1 0 | ????? | ????? + 0 1 1 | ????? | ????? + 1 0 0 | ????? | ????? + 1 0 1 | ????? | ????? + 1 1 0 | ????? | ????? + 1 1 1 | ????? | ????? + + +Setting the Node ID +^^^^^^^^^^^^^^^^^^^ + +The eight switches in group SW3 are used to set the node ID. +Each node attached to the network must have an unique node ID which +must be different from 0. +Switch 1 serves as the least significant bit (LSB). +switches in the DOWN position are OFF (0) and in the UP position are ON (1) + +The node ID is the sum of the values of all switches set to "1" +These values are:: + + Switch | Value + -------|------- + 1 | 1 + 2 | 2 + 3 | 4 + 4 | 8 + 5 | 16 + 6 | 32 + 7 | 64 + 8 | 128 + +Some Examples:: + + Switch# | Hex | Decimal + 8 7 6 5 4 3 2 1 | Node ID | Node ID + ----------------|---------|--------- + 0 0 0 0 0 0 0 0 | not allowed <-. + 0 0 0 0 0 0 0 1 | 1 | 1 | + 0 0 0 0 0 0 1 0 | 2 | 2 | + 0 0 0 0 0 0 1 1 | 3 | 3 | + . . . | | | + 0 1 0 1 0 1 0 1 | 55 | 85 | + . . . | | + Don't use 0 or 255! + 1 0 1 0 1 0 1 0 | AA | 170 | + . . . | | | + 1 1 1 1 1 1 0 1 | FD | 253 | + 1 1 1 1 1 1 1 0 | FE | 254 | + 1 1 1 1 1 1 1 1 | FF | 255 <-' + + +Tiara +===== + +(model unknown) +--------------- + + - from Christoph Lameter <christoph@lameter.com> + + +Here is information about my card as far as I could figure it out:: + + + ----------------------------------------------- tiara + Tiara LanCard of Tiara Computer Systems. + + +----------------------------------------------+ + ! ! Transmitter Unit ! ! + ! +------------------+ ------- + ! MEM Coax Connector + ! ROM 7654321 <- I/O ------- + ! : : +--------+ ! + ! : : ! 90C66LJ! +++ + ! : : ! ! !D Switch to set + ! : : ! ! !I the Nodenumber + ! : : +--------+ !P + ! !++ + ! 234567 <- IRQ ! + +------------!!!!!!!!!!!!!!!!!!!!!!!!--------+ + !!!!!!!!!!!!!!!!!!!!!!!! + +- 0 = Jumper Installed +- 1 = Open + +Top Jumper line Bit 7 = ROM Enable 654=Memory location 321=I/O + +Settings for Memory Location (Top Jumper Line) + +=== ================ +456 Address selected +=== ================ +000 C0000 +001 C4000 +010 CC000 +011 D0000 +100 D4000 +101 D8000 +110 DC000 +111 E0000 +=== ================ + +Settings for I/O Address (Top Jumper Line) + +=== ==== +123 Port +=== ==== +000 260 +001 290 +010 2E0 +011 2F0 +100 300 +101 350 +110 380 +111 3E0 +=== ==== + +Settings for IRQ Selection (Lower Jumper Line) + +====== ===== +234567 +====== ===== +011111 IRQ 2 +101111 IRQ 3 +110111 IRQ 4 +111011 IRQ 5 +111110 IRQ 7 +====== ===== + +Other Cards +=========== + +I have no information on other models of ARCnet cards at the moment. Please +send any and all info to: + + apenwarr@worldvisions.ca + +Thanks. diff --git a/Documentation/networking/arcnet.rst b/Documentation/networking/arcnet.rst new file mode 100644 index 0000000000..82fce606c0 --- /dev/null +++ b/Documentation/networking/arcnet.rst @@ -0,0 +1,594 @@ +.. SPDX-License-Identifier: GPL-2.0 + +====== +ARCnet +====== + +.. note:: + + See also arcnet-hardware.txt in this directory for jumper-setting + and cabling information if you're like many of us and didn't happen to get a + manual with your ARCnet card. + +Since no one seems to listen to me otherwise, perhaps a poem will get your +attention:: + + This driver's getting fat and beefy, + But my cat is still named Fifi. + +Hmm, I think I'm allowed to call that a poem, even though it's only two +lines. Hey, I'm in Computer Science, not English. Give me a break. + +The point is: I REALLY REALLY REALLY REALLY REALLY want to hear from you if +you test this and get it working. Or if you don't. Or anything. + +ARCnet 0.32 ALPHA first made it into the Linux kernel 1.1.80 - this was +nice, but after that even FEWER people started writing to me because they +didn't even have to install the patch. <sigh> + +Come on, be a sport! Send me a success report! + +(hey, that was even better than my original poem... this is getting bad!) + + +.. warning:: + + If you don't e-mail me about your success/failure soon, I may be forced to + start SINGING. And we don't want that, do we? + + (You know, it might be argued that I'm pushing this point a little too much. + If you think so, why not flame me in a quick little e-mail? Please also + include the type of card(s) you're using, software, size of network, and + whether it's working or not.) + + My e-mail address is: apenwarr@worldvisions.ca + +These are the ARCnet drivers for Linux. + +This new release (2.91) has been put together by David Woodhouse +<dwmw2@infradead.org>, in an attempt to tidy up the driver after adding support +for yet another chipset. Now the generic support has been separated from the +individual chipset drivers, and the source files aren't quite so packed with +#ifdefs! I've changed this file a bit, but kept it in the first person from +Avery, because I didn't want to completely rewrite it. + +The previous release resulted from many months of on-and-off effort from me +(Avery Pennarun), many bug reports/fixes and suggestions from others, and in +particular a lot of input and coding from Tomasz Motylewski. Starting with +ARCnet 2.10 ALPHA, Tomasz's all-new-and-improved RFC1051 support has been +included and seems to be working fine! + + +Where do I discuss these drivers? +--------------------------------- + +Tomasz has been so kind as to set up a new and improved mailing list. +Subscribe by sending a message with the BODY "subscribe linux-arcnet YOUR +REAL NAME" to listserv@tichy.ch.uj.edu.pl. Then, to submit messages to the +list, mail to linux-arcnet@tichy.ch.uj.edu.pl. + +There are archives of the mailing list at: + + http://epistolary.org/mailman/listinfo.cgi/arcnet + +The people on linux-net@vger.kernel.org (now defunct, replaced by +netdev@vger.kernel.org) have also been known to be very helpful, especially +when we're talking about ALPHA Linux kernels that may or may not work right +in the first place. + + +Other Drivers and Info +---------------------- + +You can try my ARCNET page on the World Wide Web at: + + http://www.qis.net/~jschmitz/arcnet/ + +Also, SMC (one of the companies that makes ARCnet cards) has a WWW site you +might be interested in, which includes several drivers for various cards +including ARCnet. Try: + + http://www.smc.com/ + +Performance Technologies makes various network software that supports +ARCnet: + + http://www.perftech.com/ or ftp to ftp.perftech.com. + +Novell makes a networking stack for DOS which includes ARCnet drivers. Try +FTPing to ftp.novell.com. + +You can get the Crynwr packet driver collection (including arcether.com, the +one you'll want to use with ARCnet cards) from +oak.oakland.edu:/simtel/msdos/pktdrvr. It won't work perfectly on a 386+ +without patches, though, and also doesn't like several cards. Fixed +versions are available on my WWW page, or via e-mail if you don't have WWW +access. + + +Installing the Driver +--------------------- + +All you will need to do in order to install the driver is:: + + make config + (be sure to choose ARCnet in the network devices + and at least one chipset driver.) + make clean + make zImage + +If you obtained this ARCnet package as an upgrade to the ARCnet driver in +your current kernel, you will need to first copy arcnet.c over the one in +the linux/drivers/net directory. + +You will know the driver is installed properly if you get some ARCnet +messages when you reboot into the new Linux kernel. + +There are four chipset options: + + 1. Standard ARCnet COM90xx chipset. + +This is the normal ARCnet card, which you've probably got. This is the only +chipset driver which will autoprobe if not told where the card is. +It following options on the command line:: + + com90xx=[<io>[,<irq>[,<shmem>]]][,<name>] | <name> + +If you load the chipset support as a module, the options are:: + + io=<io> irq=<irq> shmem=<shmem> device=<name> + +To disable the autoprobe, just specify "com90xx=" on the kernel command line. +To specify the name alone, but allow autoprobe, just put "com90xx=<name>" + + 2. ARCnet COM20020 chipset. + +This is the new chipset from SMC with support for promiscuous mode (packet +sniffing), extra diagnostic information, etc. Unfortunately, there is no +sensible method of autoprobing for these cards. You must specify the I/O +address on the kernel command line. + +The command line options are:: + + com20020=<io>[,<irq>[,<node_ID>[,backplane[,CKP[,timeout]]]]][,name] + +If you load the chipset support as a module, the options are:: + + io=<io> irq=<irq> node=<node_ID> backplane=<backplane> clock=<CKP> + timeout=<timeout> device=<name> + +The COM20020 chipset allows you to set the node ID in software, overriding the +default which is still set in DIP switches on the card. If you don't have the +COM20020 data sheets, and you don't know what the other three options refer +to, then they won't interest you - forget them. + + 3. ARCnet COM90xx chipset in IO-mapped mode. + +This will also work with the normal ARCnet cards, but doesn't use the shared +memory. It performs less well than the above driver, but is provided in case +you have a card which doesn't support shared memory, or (strangely) in case +you have so many ARCnet cards in your machine that you run out of shmem slots. +If you don't give the IO address on the kernel command line, then the driver +will not find the card. + +The command line options are:: + + com90io=<io>[,<irq>][,<name>] + +If you load the chipset support as a module, the options are: + io=<io> irq=<irq> device=<name> + + 4. ARCnet RIM I cards. + +These are COM90xx chips which are _completely_ memory mapped. The support for +these is not tested. If you have one, please mail the author with a success +report. All options must be specified, except the device name. +Command line options:: + + arcrimi=<shmem>,<irq>,<node_ID>[,<name>] + +If you load the chipset support as a module, the options are:: + + shmem=<shmem> irq=<irq> node=<node_ID> device=<name> + + +Loadable Module Support +----------------------- + +Configure and rebuild Linux. When asked, answer 'm' to "Generic ARCnet +support" and to support for your ARCnet chipset if you want to use the +loadable module. You can also say 'y' to "Generic ARCnet support" and 'm' +to the chipset support if you wish. + +:: + + make config + make clean + make zImage + make modules + +If you're using a loadable module, you need to use insmod to load it, and +you can specify various characteristics of your card on the command +line. (In recent versions of the driver, autoprobing is much more reliable +and works as a module, so most of this is now unnecessary.) + +For example:: + + cd /usr/src/linux/modules + insmod arcnet.o + insmod com90xx.o + insmod com20020.o io=0x2e0 device=eth1 + + +Using the Driver +---------------- + +If you build your kernel with ARCnet COM90xx support included, it should +probe for your card automatically when you boot. If you use a different +chipset driver complied into the kernel, you must give the necessary options +on the kernel command line, as detailed above. + +Go read the NET-2-HOWTO and ETHERNET-HOWTO for Linux; they should be +available where you picked up this driver. Think of your ARCnet as a +souped-up (or down, as the case may be) Ethernet card. + +By the way, be sure to change all references from "eth0" to "arc0" in the +HOWTOs. Remember that ARCnet isn't a "true" Ethernet, and the device name +is DIFFERENT. + + +Multiple Cards in One Computer +------------------------------ + +Linux has pretty good support for this now, but since I've been busy, the +ARCnet driver has somewhat suffered in this respect. COM90xx support, if +compiled into the kernel, will (try to) autodetect all the installed cards. + +If you have other cards, with support compiled into the kernel, then you can +just repeat the options on the kernel command line, e.g.:: + + LILO: linux com20020=0x2e0 com20020=0x380 com90io=0x260 + +If you have the chipset support built as a loadable module, then you need to +do something like this:: + + insmod -o arc0 com90xx + insmod -o arc1 com20020 io=0x2e0 + insmod -o arc2 com90xx + +The ARCnet drivers will now sort out their names automatically. + + +How do I get it to work with...? +-------------------------------- + +NFS: + Should be fine linux->linux, just pretend you're using Ethernet cards. + oak.oakland.edu:/simtel/msdos/nfs has some nice DOS clients. There + is also a DOS-based NFS server called SOSS. It doesn't multitask + quite the way Linux does (actually, it doesn't multitask AT ALL) but + you never know what you might need. + + With AmiTCP (and possibly others), you may need to set the following + options in your Amiga nfstab: MD 1024 MR 1024 MW 1024 + (Thanks to Christian Gottschling <ferksy@indigo.tng.oche.de> + for this.) + + Probably these refer to maximum NFS data/read/write block sizes. I + don't know why the defaults on the Amiga didn't work; write to me if + you know more. + +DOS: + If you're using the freeware arcether.com, you might want to install + the driver patch from my web page. It helps with PC/TCP, and also + can get arcether to load if it timed out too quickly during + initialization. In fact, if you use it on a 386+ you REALLY need + the patch, really. + +Windows: + See DOS :) Trumpet Winsock works fine with either the Novell or + Arcether client, assuming you remember to load winpkt of course. + +LAN Manager and Windows for Workgroups: + These programs use protocols that + are incompatible with the Internet standard. They try to pretend + the cards are Ethernet, and confuse everyone else on the network. + + However, v2.00 and higher of the Linux ARCnet driver supports this + protocol via the 'arc0e' device. See the section on "Multiprotocol + Support" for more information. + + Using the freeware Samba server and clients for Linux, you can now + interface quite nicely with TCP/IP-based WfWg or Lan Manager + networks. + +Windows 95: + Tools are included with Win95 that let you use either the LANMAN + style network drivers (NDIS) or Novell drivers (ODI) to handle your + ARCnet packets. If you use ODI, you'll need to use the 'arc0' + device with Linux. If you use NDIS, then try the 'arc0e' device. + See the "Multiprotocol Support" section below if you need arc0e, + you're completely insane, and/or you need to build some kind of + hybrid network that uses both encapsulation types. + +OS/2: + I've been told it works under Warp Connect with an ARCnet driver from + SMC. You need to use the 'arc0e' interface for this. If you get + the SMC driver to work with the TCP/IP stuff included in the + "normal" Warp Bonus Pack, let me know. + + ftp.microsoft.com also has a freeware "Lan Manager for OS/2" client + which should use the same protocol as WfWg does. I had no luck + installing it under Warp, however. Please mail me with any results. + +NetBSD/AmiTCP: + These use an old version of the Internet standard ARCnet + protocol (RFC1051) which is compatible with the Linux driver v2.10 + ALPHA and above using the arc0s device. (See "Multiprotocol ARCnet" + below.) ** Newer versions of NetBSD apparently support RFC1201. + + +Using Multiprotocol ARCnet +-------------------------- + +The ARCnet driver v2.10 ALPHA supports three protocols, each on its own +"virtual network device": + + ====== =============================================================== + arc0 RFC1201 protocol, the official Internet standard which just + happens to be 100% compatible with Novell's TRXNET driver. + Version 1.00 of the ARCnet driver supported _only_ this + protocol. arc0 is the fastest of the three protocols (for + whatever reason), and allows larger packets to be used + because it supports RFC1201 "packet splitting" operations. + Unless you have a specific need to use a different protocol, + I strongly suggest that you stick with this one. + + arc0e "Ethernet-Encapsulation" which sends packets over ARCnet + that are actually a lot like Ethernet packets, including the + 6-byte hardware addresses. This protocol is compatible with + Microsoft's NDIS ARCnet driver, like the one in WfWg and + LANMAN. Because the MTU of 493 is actually smaller than the + one "required" by TCP/IP (576), there is a chance that some + network operations will not function properly. The Linux + TCP/IP layer can compensate in most cases, however, by + automatically fragmenting the TCP/IP packets to make them + fit. arc0e also works slightly more slowly than arc0, for + reasons yet to be determined. (Probably it's the smaller + MTU that does it.) + + arc0s The "[s]imple" RFC1051 protocol is the "previous" Internet + standard that is completely incompatible with the new + standard. Some software today, however, continues to + support the old standard (and only the old standard) + including NetBSD and AmiTCP. RFC1051 also does not support + RFC1201's packet splitting, and the MTU of 507 is still + smaller than the Internet "requirement," so it's quite + possible that you may run into problems. It's also slower + than RFC1201 by about 25%, for the same reason as arc0e. + + The arc0s support was contributed by Tomasz Motylewski + and modified somewhat by me. Bugs are probably my fault. + ====== =============================================================== + +You can choose not to compile arc0e and arc0s into the driver if you want - +this will save you a bit of memory and avoid confusion when eg. trying to +use the "NFS-root" stuff in recent Linux kernels. + +The arc0e and arc0s devices are created automatically when you first +ifconfig the arc0 device. To actually use them, though, you need to also +ifconfig the other virtual devices you need. There are a number of ways you +can set up your network then: + + +1. Single Protocol. + + This is the simplest way to configure your network: use just one of the + two available protocols. As mentioned above, it's a good idea to use + only arc0 unless you have a good reason (like some other software, ie. + WfWg, that only works with arc0e). + + If you need only arc0, then the following commands should get you going:: + + ifconfig arc0 MY.IP.ADD.RESS + route add MY.IP.ADD.RESS arc0 + route add -net SUB.NET.ADD.RESS arc0 + [add other local routes here] + + If you need arc0e (and only arc0e), it's a little different:: + + ifconfig arc0 MY.IP.ADD.RESS + ifconfig arc0e MY.IP.ADD.RESS + route add MY.IP.ADD.RESS arc0e + route add -net SUB.NET.ADD.RESS arc0e + + arc0s works much the same way as arc0e. + + +2. More than one protocol on the same wire. + + Now things start getting confusing. To even try it, you may need to be + partly crazy. Here's what *I* did. :) Note that I don't include arc0s in + my home network; I don't have any NetBSD or AmiTCP computers, so I only + use arc0s during limited testing. + + I have three computers on my home network; two Linux boxes (which prefer + RFC1201 protocol, for reasons listed above), and one XT that can't run + Linux but runs the free Microsoft LANMAN Client instead. + + Worse, one of the Linux computers (freedom) also has a modem and acts as + a router to my Internet provider. The other Linux box (insight) also has + its own IP address and needs to use freedom as its default gateway. The + XT (patience), however, does not have its own Internet IP address and so + I assigned it one on a "private subnet" (as defined by RFC1597). + + To start with, take a simple network with just insight and freedom. + Insight needs to: + + - talk to freedom via RFC1201 (arc0) protocol, because I like it + more and it's faster. + - use freedom as its Internet gateway. + + That's pretty easy to do. Set up insight like this:: + + ifconfig arc0 insight + route add insight arc0 + route add freedom arc0 /* I would use the subnet here (like I said + to in "single protocol" above), + but the rest of the subnet + unfortunately lies across the PPP + link on freedom, which confuses + things. */ + route add default gw freedom + + And freedom gets configured like so:: + + ifconfig arc0 freedom + route add freedom arc0 + route add insight arc0 + /* and default gateway is configured by pppd */ + + Great, now insight talks to freedom directly on arc0, and sends packets + to the Internet through freedom. If you didn't know how to do the above, + you should probably stop reading this section now because it only gets + worse. + + Now, how do I add patience into the network? It will be using LANMAN + Client, which means I need the arc0e device. It needs to be able to talk + to both insight and freedom, and also use freedom as a gateway to the + Internet. (Recall that patience has a "private IP address" which won't + work on the Internet; that's okay, I configured Linux IP masquerading on + freedom for this subnet). + + So patience (necessarily; I don't have another IP number from my + provider) has an IP address on a different subnet than freedom and + insight, but needs to use freedom as an Internet gateway. Worse, most + DOS networking programs, including LANMAN, have braindead networking + schemes that rely completely on the netmask and a 'default gateway' to + determine how to route packets. This means that to get to freedom or + insight, patience WILL send through its default gateway, regardless of + the fact that both freedom and insight (courtesy of the arc0e device) + could understand a direct transmission. + + I compensate by giving freedom an extra IP address - aliased 'gatekeeper' - + that is on my private subnet, the same subnet that patience is on. I + then define gatekeeper to be the default gateway for patience. + + To configure freedom (in addition to the commands above):: + + ifconfig arc0e gatekeeper + route add gatekeeper arc0e + route add patience arc0e + + This way, freedom will send all packets for patience through arc0e, + giving its IP address as gatekeeper (on the private subnet). When it + talks to insight or the Internet, it will use its "freedom" Internet IP + address. + + You will notice that we haven't configured the arc0e device on insight. + This would work, but is not really necessary, and would require me to + assign insight another special IP number from my private subnet. Since + both insight and patience are using freedom as their default gateway, the + two can already talk to each other. + + It's quite fortunate that I set things up like this the first time (cough + cough) because it's really handy when I boot insight into DOS. There, it + runs the Novell ODI protocol stack, which only works with RFC1201 ARCnet. + In this mode it would be impossible for insight to communicate directly + with patience, since the Novell stack is incompatible with Microsoft's + Ethernet-Encap. Without changing any settings on freedom or patience, I + simply set freedom as the default gateway for insight (now in DOS, + remember) and all the forwarding happens "automagically" between the two + hosts that would normally not be able to communicate at all. + + For those who like diagrams, I have created two "virtual subnets" on the + same physical ARCnet wire. You can picture it like this:: + + + [RFC1201 NETWORK] [ETHER-ENCAP NETWORK] + (registered Internet subnet) (RFC1597 private subnet) + + (IP Masquerade) + /---------------\ * /---------------\ + | | * | | + | +-Freedom-*-Gatekeeper-+ | + | | | * | | + \-------+-------/ | * \-------+-------/ + | | | + Insight | Patience + (Internet) + + + +It works: what now? +------------------- + +Send mail describing your setup, preferably including driver version, kernel +version, ARCnet card model, CPU type, number of systems on your network, and +list of software in use to me at the following address: + + apenwarr@worldvisions.ca + +I do send (sometimes automated) replies to all messages I receive. My email +can be weird (and also usually gets forwarded all over the place along the +way to me), so if you don't get a reply within a reasonable time, please +resend. + + +It doesn't work: what now? +-------------------------- + +Do the same as above, but also include the output of the ifconfig and route +commands, as well as any pertinent log entries (ie. anything that starts +with "arcnet:" and has shown up since the last reboot) in your mail. + +If you want to try fixing it yourself (I strongly recommend that you mail me +about the problem first, since it might already have been solved) you may +want to try some of the debug levels available. For heavy testing on +D_DURING or more, it would be a REALLY good idea to kill your klogd daemon +first! D_DURING displays 4-5 lines for each packet sent or received. D_TX, +D_RX, and D_SKB actually DISPLAY each packet as it is sent or received, +which is obviously quite big. + +Starting with v2.40 ALPHA, the autoprobe routines have changed +significantly. In particular, they won't tell you why the card was not +found unless you turn on the D_INIT_REASONS debugging flag. + +Once the driver is running, you can run the arcdump shell script (available +from me or in the full ARCnet package, if you have it) as root to list the +contents of the arcnet buffers at any time. To make any sense at all out of +this, you should grab the pertinent RFCs. (some are listed near the top of +arcnet.c). arcdump assumes your card is at 0xD0000. If it isn't, edit the +script. + +Buffers 0 and 1 are used for receiving, and Buffers 2 and 3 are for sending. +Ping-pong buffers are implemented both ways. + +If your debug level includes D_DURING and you did NOT define SLOW_XMIT_COPY, +the buffers are cleared to a constant value of 0x42 every time the card is +reset (which should only happen when you do an ifconfig up, or when Linux +decides that the driver is broken). During a transmit, unused parts of the +buffer will be cleared to 0x42 as well. This is to make it easier to figure +out which bytes are being used by a packet. + +You can change the debug level without recompiling the kernel by typing:: + + ifconfig arc0 down metric 1xxx + /etc/rc.d/rc.inet1 + +where "xxx" is the debug level you want. For example, "metric 1015" would put +you at debug level 15. Debug level 7 is currently the default. + +Note that the debug level is (starting with v1.90 ALPHA) a binary +combination of different debug flags; so debug level 7 is really 1+2+4 or +D_NORMAL+D_EXTRA+D_INIT. To include D_DURING, you would add 16 to this, +resulting in debug level 23. + +If you don't understand that, you probably don't want to know anyway. +E-mail me about your problem. + + +I want to send money: what now? +------------------------------- + +Go take a nap or something. You'll feel better in the morning. diff --git a/Documentation/networking/atm.rst b/Documentation/networking/atm.rst new file mode 100644 index 0000000000..c1df8c0385 --- /dev/null +++ b/Documentation/networking/atm.rst @@ -0,0 +1,14 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=== +ATM +=== + +In order to use anything but the most primitive functions of ATM, +several user-mode programs are required to assist the kernel. These +programs and related material can be found via the ATM on Linux Web +page at http://linux-atm.sourceforge.net/ + +If you encounter problems with ATM, please report them on the ATM +on Linux mailing list. Subscription information, archives, etc., +can be found on http://linux-atm.sourceforge.net/ diff --git a/Documentation/networking/ax25.rst b/Documentation/networking/ax25.rst new file mode 100644 index 0000000000..605e72c6c8 --- /dev/null +++ b/Documentation/networking/ax25.rst @@ -0,0 +1,16 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===== +AX.25 +===== + +To use the amateur radio protocols within Linux you will need to get a +suitable copy of the AX.25 Utilities. More detailed information about +AX.25, NET/ROM and ROSE, associated programs and utilities can be +found on https://linux-ax25.in-berlin.de. + +There is a mailing list for discussing Linux amateur radio matters +called linux-hams@vger.kernel.org. To subscribe to it, send a message to +majordomo@vger.kernel.org with the words "subscribe linux-hams" in the body +of the message, the subject field is ignored. You don't need to be +subscribed to post but of course that means you might miss an answer. diff --git a/Documentation/networking/bareudp.rst b/Documentation/networking/bareudp.rst new file mode 100644 index 0000000000..b9d04ee6da --- /dev/null +++ b/Documentation/networking/bareudp.rst @@ -0,0 +1,58 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======================================== +Bare UDP Tunnelling Module Documentation +======================================== + +There are various L3 encapsulation standards using UDP being discussed to +leverage the UDP based load balancing capability of different networks. +MPLSoUDP (__ https://tools.ietf.org/html/rfc7510) is one among them. + +The Bareudp tunnel module provides a generic L3 encapsulation support for +tunnelling different L3 protocols like MPLS, IP, NSH etc. inside a UDP tunnel. + +Special Handling +---------------- +The bareudp device supports special handling for MPLS & IP as they can have +multiple ethertypes. +MPLS procotcol can have ethertypes ETH_P_MPLS_UC (unicast) & ETH_P_MPLS_MC (multicast). +IP protocol can have ethertypes ETH_P_IP (v4) & ETH_P_IPV6 (v6). +This special handling can be enabled only for ethertypes ETH_P_IP & ETH_P_MPLS_UC +with a flag called multiproto mode. + +Usage +------ + +1) Device creation & deletion + + a) ip link add dev bareudp0 type bareudp dstport 6635 ethertype mpls_uc + + This creates a bareudp tunnel device which tunnels L3 traffic with ethertype + 0x8847 (MPLS traffic). The destination port of the UDP header will be set to + 6635.The device will listen on UDP port 6635 to receive traffic. + + b) ip link delete bareudp0 + +2) Device creation with multiproto mode enabled + +The multiproto mode allows bareudp tunnels to handle several protocols of the +same family. It is currently only available for IP and MPLS. This mode has to +be enabled explicitly with the "multiproto" flag. + + a) ip link add dev bareudp0 type bareudp dstport 6635 ethertype ipv4 multiproto + + For an IPv4 tunnel the multiproto mode allows the tunnel to also handle + IPv6. + + b) ip link add dev bareudp0 type bareudp dstport 6635 ethertype mpls_uc multiproto + + For MPLS, the multiproto mode allows the tunnel to handle both unicast + and multicast MPLS packets. + +3) Device Usage + +The bareudp device could be used along with OVS or flower filter in TC. +The OVS or TC flower layer must set the tunnel information in SKB dst field before +sending packet buffer to the bareudp device for transmission. On reception the +bareudp device extracts and stores the tunnel information in SKB dst field before +passing the packet buffer to the network stack. diff --git a/Documentation/networking/batman-adv.rst b/Documentation/networking/batman-adv.rst new file mode 100644 index 0000000000..8a0dcb1894 --- /dev/null +++ b/Documentation/networking/batman-adv.rst @@ -0,0 +1,168 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========== +batman-adv +========== + +Batman advanced is a new approach to wireless networking which does no longer +operate on the IP basis. Unlike the batman daemon, which exchanges information +using UDP packets and sets routing tables, batman-advanced operates on ISO/OSI +Layer 2 only and uses and routes (or better: bridges) Ethernet Frames. It +emulates a virtual network switch of all nodes participating. Therefore all +nodes appear to be link local, thus all higher operating protocols won't be +affected by any changes within the network. You can run almost any protocol +above batman advanced, prominent examples are: IPv4, IPv6, DHCP, IPX. + +Batman advanced was implemented as a Linux kernel driver to reduce the overhead +to a minimum. It does not depend on any (other) network driver, and can be used +on wifi as well as ethernet lan, vpn, etc ... (anything with ethernet-style +layer 2). + + +Configuration +============= + +Load the batman-adv module into your kernel:: + + $ insmod batman-adv.ko + +The module is now waiting for activation. You must add some interfaces on which +batman-adv can operate. The batman-adv soft-interface can be created using the +iproute2 tool ``ip``:: + + $ ip link add name bat0 type batadv + +To activate a given interface simply attach it to the ``bat0`` interface:: + + $ ip link set dev eth0 master bat0 + +Repeat this step for all interfaces you wish to add. Now batman-adv starts +using/broadcasting on this/these interface(s). + +To deactivate an interface you have to detach it from the "bat0" interface:: + + $ ip link set dev eth0 nomaster + +The same can also be done using the batctl interface subcommand:: + + batctl -m bat0 interface create + batctl -m bat0 interface add -M eth0 + +To detach eth0 and destroy bat0:: + + batctl -m bat0 interface del -M eth0 + batctl -m bat0 interface destroy + +There are additional settings for each batadv mesh interface, vlan and hardif +which can be modified using batctl. Detailed information about this can be found +in its manual. + +For instance, you can check the current originator interval (value +in milliseconds which determines how often batman-adv sends its broadcast +packets):: + + $ batctl -M bat0 orig_interval + 1000 + +and also change its value:: + + $ batctl -M bat0 orig_interval 3000 + +In very mobile scenarios, you might want to adjust the originator interval to a +lower value. This will make the mesh more responsive to topology changes, but +will also increase the overhead. + +Information about the current state can be accessed via the batadv generic +netlink family. batctl provides a human readable version via its debug tables +subcommands. + + +Usage +===== + +To make use of your newly created mesh, batman advanced provides a new +interface "bat0" which you should use from this point on. All interfaces added +to batman advanced are not relevant any longer because batman handles them for +you. Basically, one "hands over" the data by using the batman interface and +batman will make sure it reaches its destination. + +The "bat0" interface can be used like any other regular interface. It needs an +IP address which can be either statically configured or dynamically (by using +DHCP or similar services):: + + NodeA: ip link set up dev bat0 + NodeA: ip addr add 192.168.0.1/24 dev bat0 + + NodeB: ip link set up dev bat0 + NodeB: ip addr add 192.168.0.2/24 dev bat0 + NodeB: ping 192.168.0.1 + +Note: In order to avoid problems remove all IP addresses previously assigned to +interfaces now used by batman advanced, e.g.:: + + $ ip addr flush dev eth0 + + +Logging/Debugging +================= + +All error messages, warnings and information messages are sent to the kernel +log. Depending on your operating system distribution this can be read in one of +a number of ways. Try using the commands: ``dmesg``, ``logread``, or looking in +the files ``/var/log/kern.log`` or ``/var/log/syslog``. All batman-adv messages +are prefixed with "batman-adv:" So to see just these messages try:: + + $ dmesg | grep batman-adv + +When investigating problems with your mesh network, it is sometimes necessary to +see more detailed debug messages. This must be enabled when compiling the +batman-adv module. When building batman-adv as part of the kernel, use "make +menuconfig" and enable the option ``B.A.T.M.A.N. debugging`` +(``CONFIG_BATMAN_ADV_DEBUG=y``). + +Those additional debug messages can be accessed using the perf infrastructure:: + + $ trace-cmd stream -e batadv:batadv_dbg + +The additional debug output is by default disabled. It can be enabled during +run time:: + + $ batctl -m bat0 loglevel routes tt + +will enable debug messages for when routes and translation table entries change. + +Counters for different types of packets entering and leaving the batman-adv +module are available through ethtool:: + + $ ethtool --statistics bat0 + + +batctl +====== + +As batman advanced operates on layer 2, all hosts participating in the virtual +switch are completely transparent for all protocols above layer 2. Therefore +the common diagnosis tools do not work as expected. To overcome these problems, +batctl was created. At the moment the batctl contains ping, traceroute, tcpdump +and interfaces to the kernel module settings. + +For more information, please see the manpage (``man batctl``). + +batctl is available on https://www.open-mesh.org/ + + +Contact +======= + +Please send us comments, experiences, questions, anything :) + +IRC: + #batadv on ircs://irc.hackint.org/ +Mailing-list: + b.a.t.m.a.n@lists.open-mesh.org (optional subscription at + https://lists.open-mesh.org/mailman3/postorius/lists/b.a.t.m.a.n.lists.open-mesh.org/) + +You can also contact the Authors: + +* Marek Lindner <mareklindner@neomailbox.ch> +* Simon Wunderlich <sw@simonwunderlich.de> diff --git a/Documentation/networking/bonding.rst b/Documentation/networking/bonding.rst new file mode 100644 index 0000000000..f7a73421eb --- /dev/null +++ b/Documentation/networking/bonding.rst @@ -0,0 +1,2925 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=================================== +Linux Ethernet Bonding Driver HOWTO +=================================== + +Latest update: 27 April 2011 + +Initial release: Thomas Davis <tadavis at lbl.gov> + +Corrections, HA extensions: 2000/10/03-15: + + - Willy Tarreau <willy at meta-x.org> + - Constantine Gavrilov <const-g at xpert.com> + - Chad N. Tindel <ctindel at ieee dot org> + - Janice Girouard <girouard at us dot ibm dot com> + - Jay Vosburgh <fubar at us dot ibm dot com> + +Reorganized and updated Feb 2005 by Jay Vosburgh +Added Sysfs information: 2006/04/24 + + - Mitch Williams <mitch.a.williams at intel.com> + +Introduction +============ + +The Linux bonding driver provides a method for aggregating +multiple network interfaces into a single logical "bonded" interface. +The behavior of the bonded interfaces depends upon the mode; generally +speaking, modes provide either hot standby or load balancing services. +Additionally, link integrity monitoring may be performed. + +The bonding driver originally came from Donald Becker's +beowulf patches for kernel 2.0. It has changed quite a bit since, and +the original tools from extreme-linux and beowulf sites will not work +with this version of the driver. + +For new versions of the driver, updated userspace tools, and +who to ask for help, please follow the links at the end of this file. + +.. Table of Contents + + 1. Bonding Driver Installation + + 2. Bonding Driver Options + + 3. Configuring Bonding Devices + 3.1 Configuration with Sysconfig Support + 3.1.1 Using DHCP with Sysconfig + 3.1.2 Configuring Multiple Bonds with Sysconfig + 3.2 Configuration with Initscripts Support + 3.2.1 Using DHCP with Initscripts + 3.2.2 Configuring Multiple Bonds with Initscripts + 3.3 Configuring Bonding Manually with Ifenslave + 3.3.1 Configuring Multiple Bonds Manually + 3.4 Configuring Bonding Manually via Sysfs + 3.5 Configuration with Interfaces Support + 3.6 Overriding Configuration for Special Cases + 3.7 Configuring LACP for 802.3ad mode in a more secure way + + 4. Querying Bonding Configuration + 4.1 Bonding Configuration + 4.2 Network Configuration + + 5. Switch Configuration + + 6. 802.1q VLAN Support + + 7. Link Monitoring + 7.1 ARP Monitor Operation + 7.2 Configuring Multiple ARP Targets + 7.3 MII Monitor Operation + + 8. Potential Trouble Sources + 8.1 Adventures in Routing + 8.2 Ethernet Device Renaming + 8.3 Painfully Slow Or No Failed Link Detection By Miimon + + 9. SNMP agents + + 10. Promiscuous mode + + 11. Configuring Bonding for High Availability + 11.1 High Availability in a Single Switch Topology + 11.2 High Availability in a Multiple Switch Topology + 11.2.1 HA Bonding Mode Selection for Multiple Switch Topology + 11.2.2 HA Link Monitoring for Multiple Switch Topology + + 12. Configuring Bonding for Maximum Throughput + 12.1 Maximum Throughput in a Single Switch Topology + 12.1.1 MT Bonding Mode Selection for Single Switch Topology + 12.1.2 MT Link Monitoring for Single Switch Topology + 12.2 Maximum Throughput in a Multiple Switch Topology + 12.2.1 MT Bonding Mode Selection for Multiple Switch Topology + 12.2.2 MT Link Monitoring for Multiple Switch Topology + + 13. Switch Behavior Issues + 13.1 Link Establishment and Failover Delays + 13.2 Duplicated Incoming Packets + + 14. Hardware Specific Considerations + 14.1 IBM BladeCenter + + 15. Frequently Asked Questions + + 16. Resources and Links + + +1. Bonding Driver Installation +============================== + +Most popular distro kernels ship with the bonding driver +already available as a module. If your distro does not, or you +have need to compile bonding from source (e.g., configuring and +installing a mainline kernel from kernel.org), you'll need to perform +the following steps: + +1.1 Configure and build the kernel with bonding +----------------------------------------------- + +The current version of the bonding driver is available in the +drivers/net/bonding subdirectory of the most recent kernel source +(which is available on http://kernel.org). Most users "rolling their +own" will want to use the most recent kernel from kernel.org. + +Configure kernel with "make menuconfig" (or "make xconfig" or +"make config"), then select "Bonding driver support" in the "Network +device support" section. It is recommended that you configure the +driver as module since it is currently the only way to pass parameters +to the driver or configure more than one bonding device. + +Build and install the new kernel and modules. + +1.2 Bonding Control Utility +--------------------------- + +It is recommended to configure bonding via iproute2 (netlink) +or sysfs, the old ifenslave control utility is obsolete. + +2. Bonding Driver Options +========================= + +Options for the bonding driver are supplied as parameters to the +bonding module at load time, or are specified via sysfs. + +Module options may be given as command line arguments to the +insmod or modprobe command, but are usually specified in either the +``/etc/modprobe.d/*.conf`` configuration files, or in a distro-specific +configuration file (some of which are detailed in the next section). + +Details on bonding support for sysfs is provided in the +"Configuring Bonding Manually via Sysfs" section, below. + +The available bonding driver parameters are listed below. If a +parameter is not specified the default value is used. When initially +configuring a bond, it is recommended "tail -f /var/log/messages" be +run in a separate window to watch for bonding driver error messages. + +It is critical that either the miimon or arp_interval and +arp_ip_target parameters be specified, otherwise serious network +degradation will occur during link failures. Very few devices do not +support at least miimon, so there is really no reason not to use it. + +Options with textual values will accept either the text name +or, for backwards compatibility, the option value. E.g., +"mode=802.3ad" and "mode=4" set the same mode. + +The parameters are as follows: + +active_slave + + Specifies the new active slave for modes that support it + (active-backup, balance-alb and balance-tlb). Possible values + are the name of any currently enslaved interface, or an empty + string. If a name is given, the slave and its link must be up in order + to be selected as the new active slave. If an empty string is + specified, the current active slave is cleared, and a new active + slave is selected automatically. + + Note that this is only available through the sysfs interface. No module + parameter by this name exists. + + The normal value of this option is the name of the currently + active slave, or the empty string if there is no active slave or + the current mode does not use an active slave. + +ad_actor_sys_prio + + In an AD system, this specifies the system priority. The allowed range + is 1 - 65535. If the value is not specified, it takes 65535 as the + default value. + + This parameter has effect only in 802.3ad mode and is available through + SysFs interface. + +ad_actor_system + + In an AD system, this specifies the mac-address for the actor in + protocol packet exchanges (LACPDUs). The value cannot be a multicast + address. If the all-zeroes MAC is specified, bonding will internally + use the MAC of the bond itself. It is preferred to have the + local-admin bit set for this mac but driver does not enforce it. If + the value is not given then system defaults to using the masters' + mac address as actors' system address. + + This parameter has effect only in 802.3ad mode and is available through + SysFs interface. + +ad_select + + Specifies the 802.3ad aggregation selection logic to use. The + possible values and their effects are: + + stable or 0 + + The active aggregator is chosen by largest aggregate + bandwidth. + + Reselection of the active aggregator occurs only when all + slaves of the active aggregator are down or the active + aggregator has no slaves. + + This is the default value. + + bandwidth or 1 + + The active aggregator is chosen by largest aggregate + bandwidth. Reselection occurs if: + + - A slave is added to or removed from the bond + + - Any slave's link state changes + + - Any slave's 802.3ad association state changes + + - The bond's administrative state changes to up + + count or 2 + + The active aggregator is chosen by the largest number of + ports (slaves). Reselection occurs as described under the + "bandwidth" setting, above. + + The bandwidth and count selection policies permit failover of + 802.3ad aggregations when partial failure of the active aggregator + occurs. This keeps the aggregator with the highest availability + (either in bandwidth or in number of ports) active at all times. + + This option was added in bonding version 3.4.0. + +ad_user_port_key + + In an AD system, the port-key has three parts as shown below - + + ===== ============ + Bits Use + ===== ============ + 00 Duplex + 01-05 Speed + 06-15 User-defined + ===== ============ + + This defines the upper 10 bits of the port key. The values can be + from 0 - 1023. If not given, the system defaults to 0. + + This parameter has effect only in 802.3ad mode and is available through + SysFs interface. + +all_slaves_active + + Specifies that duplicate frames (received on inactive ports) should be + dropped (0) or delivered (1). + + Normally, bonding will drop duplicate frames (received on inactive + ports), which is desirable for most users. But there are some times + it is nice to allow duplicate frames to be delivered. + + The default value is 0 (drop duplicate frames received on inactive + ports). + +arp_interval + + Specifies the ARP link monitoring frequency in milliseconds. + + The ARP monitor works by periodically checking the slave + devices to determine whether they have sent or received + traffic recently (the precise criteria depends upon the + bonding mode, and the state of the slave). Regular traffic is + generated via ARP probes issued for the addresses specified by + the arp_ip_target option. + + This behavior can be modified by the arp_validate option, + below. + + If ARP monitoring is used in an etherchannel compatible mode + (modes 0 and 2), the switch should be configured in a mode + that evenly distributes packets across all links. If the + switch is configured to distribute the packets in an XOR + fashion, all replies from the ARP targets will be received on + the same link which could cause the other team members to + fail. ARP monitoring should not be used in conjunction with + miimon. A value of 0 disables ARP monitoring. The default + value is 0. + +arp_ip_target + + Specifies the IP addresses to use as ARP monitoring peers when + arp_interval is > 0. These are the targets of the ARP request + sent to determine the health of the link to the targets. + Specify these values in ddd.ddd.ddd.ddd format. Multiple IP + addresses must be separated by a comma. At least one IP + address must be given for ARP monitoring to function. The + maximum number of targets that can be specified is 16. The + default value is no IP addresses. + +ns_ip6_target + + Specifies the IPv6 addresses to use as IPv6 monitoring peers when + arp_interval is > 0. These are the targets of the NS request + sent to determine the health of the link to the targets. + Specify these values in ffff:ffff::ffff:ffff format. Multiple IPv6 + addresses must be separated by a comma. At least one IPv6 + address must be given for NS/NA monitoring to function. The + maximum number of targets that can be specified is 16. The + default value is no IPv6 addresses. + +arp_validate + + Specifies whether or not ARP probes and replies should be + validated in any mode that supports arp monitoring, or whether + non-ARP traffic should be filtered (disregarded) for link + monitoring purposes. + + Possible values are: + + none or 0 + + No validation or filtering is performed. + + active or 1 + + Validation is performed only for the active slave. + + backup or 2 + + Validation is performed only for backup slaves. + + all or 3 + + Validation is performed for all slaves. + + filter or 4 + + Filtering is applied to all slaves. No validation is + performed. + + filter_active or 5 + + Filtering is applied to all slaves, validation is performed + only for the active slave. + + filter_backup or 6 + + Filtering is applied to all slaves, validation is performed + only for backup slaves. + + Validation: + + Enabling validation causes the ARP monitor to examine the incoming + ARP requests and replies, and only consider a slave to be up if it + is receiving the appropriate ARP traffic. + + For an active slave, the validation checks ARP replies to confirm + that they were generated by an arp_ip_target. Since backup slaves + do not typically receive these replies, the validation performed + for backup slaves is on the broadcast ARP request sent out via the + active slave. It is possible that some switch or network + configurations may result in situations wherein the backup slaves + do not receive the ARP requests; in such a situation, validation + of backup slaves must be disabled. + + The validation of ARP requests on backup slaves is mainly helping + bonding to decide which slaves are more likely to work in case of + the active slave failure, it doesn't really guarantee that the + backup slave will work if it's selected as the next active slave. + + Validation is useful in network configurations in which multiple + bonding hosts are concurrently issuing ARPs to one or more targets + beyond a common switch. Should the link between the switch and + target fail (but not the switch itself), the probe traffic + generated by the multiple bonding instances will fool the standard + ARP monitor into considering the links as still up. Use of + validation can resolve this, as the ARP monitor will only consider + ARP requests and replies associated with its own instance of + bonding. + + Filtering: + + Enabling filtering causes the ARP monitor to only use incoming ARP + packets for link availability purposes. Arriving packets that are + not ARPs are delivered normally, but do not count when determining + if a slave is available. + + Filtering operates by only considering the reception of ARP + packets (any ARP packet, regardless of source or destination) when + determining if a slave has received traffic for link availability + purposes. + + Filtering is useful in network configurations in which significant + levels of third party broadcast traffic would fool the standard + ARP monitor into considering the links as still up. Use of + filtering can resolve this, as only ARP traffic is considered for + link availability purposes. + + This option was added in bonding version 3.1.0. + +arp_all_targets + + Specifies the quantity of arp_ip_targets that must be reachable + in order for the ARP monitor to consider a slave as being up. + This option affects only active-backup mode for slaves with + arp_validation enabled. + + Possible values are: + + any or 0 + + consider the slave up only when any of the arp_ip_targets + is reachable + + all or 1 + + consider the slave up only when all of the arp_ip_targets + are reachable + +arp_missed_max + + Specifies the number of arp_interval monitor checks that must + fail in order for an interface to be marked down by the ARP monitor. + + In order to provide orderly failover semantics, backup interfaces + are permitted an extra monitor check (i.e., they must fail + arp_missed_max + 1 times before being marked down). + + The default value is 2, and the allowable range is 1 - 255. + +downdelay + + Specifies the time, in milliseconds, to wait before disabling + a slave after a link failure has been detected. This option + is only valid for the miimon link monitor. The downdelay + value should be a multiple of the miimon value; if not, it + will be rounded down to the nearest multiple. The default + value is 0. + +fail_over_mac + + Specifies whether active-backup mode should set all slaves to + the same MAC address at enslavement (the traditional + behavior), or, when enabled, perform special handling of the + bond's MAC address in accordance with the selected policy. + + Possible values are: + + none or 0 + + This setting disables fail_over_mac, and causes + bonding to set all slaves of an active-backup bond to + the same MAC address at enslavement time. This is the + default. + + active or 1 + + The "active" fail_over_mac policy indicates that the + MAC address of the bond should always be the MAC + address of the currently active slave. The MAC + address of the slaves is not changed; instead, the MAC + address of the bond changes during a failover. + + This policy is useful for devices that cannot ever + alter their MAC address, or for devices that refuse + incoming broadcasts with their own source MAC (which + interferes with the ARP monitor). + + The down side of this policy is that every device on + the network must be updated via gratuitous ARP, + vs. just updating a switch or set of switches (which + often takes place for any traffic, not just ARP + traffic, if the switch snoops incoming traffic to + update its tables) for the traditional method. If the + gratuitous ARP is lost, communication may be + disrupted. + + When this policy is used in conjunction with the mii + monitor, devices which assert link up prior to being + able to actually transmit and receive are particularly + susceptible to loss of the gratuitous ARP, and an + appropriate updelay setting may be required. + + follow or 2 + + The "follow" fail_over_mac policy causes the MAC + address of the bond to be selected normally (normally + the MAC address of the first slave added to the bond). + However, the second and subsequent slaves are not set + to this MAC address while they are in a backup role; a + slave is programmed with the bond's MAC address at + failover time (and the formerly active slave receives + the newly active slave's MAC address). + + This policy is useful for multiport devices that + either become confused or incur a performance penalty + when multiple ports are programmed with the same MAC + address. + + + The default policy is none, unless the first slave cannot + change its MAC address, in which case the active policy is + selected by default. + + This option may be modified via sysfs only when no slaves are + present in the bond. + + This option was added in bonding version 3.2.0. The "follow" + policy was added in bonding version 3.3.0. + +lacp_active + Option specifying whether to send LACPDU frames periodically. + + off or 0 + LACPDU frames acts as "speak when spoken to". + + on or 1 + LACPDU frames are sent along the configured links + periodically. See lacp_rate for more details. + + The default is on. + +lacp_rate + + Option specifying the rate in which we'll ask our link partner + to transmit LACPDU packets in 802.3ad mode. Possible values + are: + + slow or 0 + Request partner to transmit LACPDUs every 30 seconds + + fast or 1 + Request partner to transmit LACPDUs every 1 second + + The default is slow. + +max_bonds + + Specifies the number of bonding devices to create for this + instance of the bonding driver. E.g., if max_bonds is 3, and + the bonding driver is not already loaded, then bond0, bond1 + and bond2 will be created. The default value is 1. Specifying + a value of 0 will load bonding, but will not create any devices. + +miimon + + Specifies the MII link monitoring frequency in milliseconds. + This determines how often the link state of each slave is + inspected for link failures. A value of zero disables MII + link monitoring. A value of 100 is a good starting point. + The use_carrier option, below, affects how the link state is + determined. See the High Availability section for additional + information. The default value is 100 if arp_interval is not + set. + +min_links + + Specifies the minimum number of links that must be active before + asserting carrier. It is similar to the Cisco EtherChannel min-links + feature. This allows setting the minimum number of member ports that + must be up (link-up state) before marking the bond device as up + (carrier on). This is useful for situations where higher level services + such as clustering want to ensure a minimum number of low bandwidth + links are active before switchover. This option only affect 802.3ad + mode. + + The default value is 0. This will cause carrier to be asserted (for + 802.3ad mode) whenever there is an active aggregator, regardless of the + number of available links in that aggregator. Note that, because an + aggregator cannot be active without at least one available link, + setting this option to 0 or to 1 has the exact same effect. + +mode + + Specifies one of the bonding policies. The default is + balance-rr (round robin). Possible values are: + + balance-rr or 0 + + Round-robin policy: Transmit packets in sequential + order from the first available slave through the + last. This mode provides load balancing and fault + tolerance. + + active-backup or 1 + + Active-backup policy: Only one slave in the bond is + active. A different slave becomes active if, and only + if, the active slave fails. The bond's MAC address is + externally visible on only one port (network adapter) + to avoid confusing the switch. + + In bonding version 2.6.2 or later, when a failover + occurs in active-backup mode, bonding will issue one + or more gratuitous ARPs on the newly active slave. + One gratuitous ARP is issued for the bonding master + interface and each VLAN interfaces configured above + it, provided that the interface has at least one IP + address configured. Gratuitous ARPs issued for VLAN + interfaces are tagged with the appropriate VLAN id. + + This mode provides fault tolerance. The primary + option, documented below, affects the behavior of this + mode. + + balance-xor or 2 + + XOR policy: Transmit based on the selected transmit + hash policy. The default policy is a simple [(source + MAC address XOR'd with destination MAC address XOR + packet type ID) modulo slave count]. Alternate transmit + policies may be selected via the xmit_hash_policy option, + described below. + + This mode provides load balancing and fault tolerance. + + broadcast or 3 + + Broadcast policy: transmits everything on all slave + interfaces. This mode provides fault tolerance. + + 802.3ad or 4 + + IEEE 802.3ad Dynamic link aggregation. Creates + aggregation groups that share the same speed and + duplex settings. Utilizes all slaves in the active + aggregator according to the 802.3ad specification. + + Slave selection for outgoing traffic is done according + to the transmit hash policy, which may be changed from + the default simple XOR policy via the xmit_hash_policy + option, documented below. Note that not all transmit + policies may be 802.3ad compliant, particularly in + regards to the packet mis-ordering requirements of + section 43.2.4 of the 802.3ad standard. Differing + peer implementations will have varying tolerances for + noncompliance. + + Prerequisites: + + 1. Ethtool support in the base drivers for retrieving + the speed and duplex of each slave. + + 2. A switch that supports IEEE 802.3ad Dynamic link + aggregation. + + Most switches will require some type of configuration + to enable 802.3ad mode. + + balance-tlb or 5 + + Adaptive transmit load balancing: channel bonding that + does not require any special switch support. + + In tlb_dynamic_lb=1 mode; the outgoing traffic is + distributed according to the current load (computed + relative to the speed) on each slave. + + In tlb_dynamic_lb=0 mode; the load balancing based on + current load is disabled and the load is distributed + only using the hash distribution. + + Incoming traffic is received by the current slave. + If the receiving slave fails, another slave takes over + the MAC address of the failed receiving slave. + + Prerequisite: + + Ethtool support in the base drivers for retrieving the + speed of each slave. + + balance-alb or 6 + + Adaptive load balancing: includes balance-tlb plus + receive load balancing (rlb) for IPV4 traffic, and + does not require any special switch support. The + receive load balancing is achieved by ARP negotiation. + The bonding driver intercepts the ARP Replies sent by + the local system on their way out and overwrites the + source hardware address with the unique hardware + address of one of the slaves in the bond such that + different peers use different hardware addresses for + the server. + + Receive traffic from connections created by the server + is also balanced. When the local system sends an ARP + Request the bonding driver copies and saves the peer's + IP information from the ARP packet. When the ARP + Reply arrives from the peer, its hardware address is + retrieved and the bonding driver initiates an ARP + reply to this peer assigning it to one of the slaves + in the bond. A problematic outcome of using ARP + negotiation for balancing is that each time that an + ARP request is broadcast it uses the hardware address + of the bond. Hence, peers learn the hardware address + of the bond and the balancing of receive traffic + collapses to the current slave. This is handled by + sending updates (ARP Replies) to all the peers with + their individually assigned hardware address such that + the traffic is redistributed. Receive traffic is also + redistributed when a new slave is added to the bond + and when an inactive slave is re-activated. The + receive load is distributed sequentially (round robin) + among the group of highest speed slaves in the bond. + + When a link is reconnected or a new slave joins the + bond the receive traffic is redistributed among all + active slaves in the bond by initiating ARP Replies + with the selected MAC address to each of the + clients. The updelay parameter (detailed below) must + be set to a value equal or greater than the switch's + forwarding delay so that the ARP Replies sent to the + peers will not be blocked by the switch. + + Prerequisites: + + 1. Ethtool support in the base drivers for retrieving + the speed of each slave. + + 2. Base driver support for setting the hardware + address of a device while it is open. This is + required so that there will always be one slave in the + team using the bond hardware address (the + curr_active_slave) while having a unique hardware + address for each slave in the bond. If the + curr_active_slave fails its hardware address is + swapped with the new curr_active_slave that was + chosen. + +num_grat_arp, +num_unsol_na + + Specify the number of peer notifications (gratuitous ARPs and + unsolicited IPv6 Neighbor Advertisements) to be issued after a + failover event. As soon as the link is up on the new slave + (possibly immediately) a peer notification is sent on the + bonding device and each VLAN sub-device. This is repeated at + the rate specified by peer_notif_delay if the number is + greater than 1. + + The valid range is 0 - 255; the default value is 1. These options + affect only the active-backup mode. These options were added for + bonding versions 3.3.0 and 3.4.0 respectively. + + From Linux 3.0 and bonding version 3.7.1, these notifications + are generated by the ipv4 and ipv6 code and the numbers of + repetitions cannot be set independently. + +packets_per_slave + + Specify the number of packets to transmit through a slave before + moving to the next one. When set to 0 then a slave is chosen at + random. + + The valid range is 0 - 65535; the default value is 1. This option + has effect only in balance-rr mode. + +peer_notif_delay + + Specify the delay, in milliseconds, between each peer + notification (gratuitous ARP and unsolicited IPv6 Neighbor + Advertisement) when they are issued after a failover event. + This delay should be a multiple of the MII link monitor interval + (miimon). + + The valid range is 0 - 300000. The default value is 0, which means + to match the value of the MII link monitor interval. + +prio + Slave priority. A higher number means higher priority. + The primary slave has the highest priority. This option also + follows the primary_reselect rules. + + This option could only be configured via netlink, and is only valid + for active-backup(1), balance-tlb (5) and balance-alb (6) mode. + The valid value range is a signed 32 bit integer. + + The default value is 0. + +primary + + A string (eth0, eth2, etc) specifying which slave is the + primary device. The specified device will always be the + active slave while it is available. Only when the primary is + off-line will alternate devices be used. This is useful when + one slave is preferred over another, e.g., when one slave has + higher throughput than another. + + The primary option is only valid for active-backup(1), + balance-tlb (5) and balance-alb (6) mode. + +primary_reselect + + Specifies the reselection policy for the primary slave. This + affects how the primary slave is chosen to become the active slave + when failure of the active slave or recovery of the primary slave + occurs. This option is designed to prevent flip-flopping between + the primary slave and other slaves. Possible values are: + + always or 0 (default) + + The primary slave becomes the active slave whenever it + comes back up. + + better or 1 + + The primary slave becomes the active slave when it comes + back up, if the speed and duplex of the primary slave is + better than the speed and duplex of the current active + slave. + + failure or 2 + + The primary slave becomes the active slave only if the + current active slave fails and the primary slave is up. + + The primary_reselect setting is ignored in two cases: + + If no slaves are active, the first slave to recover is + made the active slave. + + When initially enslaved, the primary slave is always made + the active slave. + + Changing the primary_reselect policy via sysfs will cause an + immediate selection of the best active slave according to the new + policy. This may or may not result in a change of the active + slave, depending upon the circumstances. + + This option was added for bonding version 3.6.0. + +tlb_dynamic_lb + + Specifies if dynamic shuffling of flows is enabled in tlb + or alb mode. The value has no effect on any other modes. + + The default behavior of tlb mode is to shuffle active flows across + slaves based on the load in that interval. This gives nice lb + characteristics but can cause packet reordering. If re-ordering is + a concern use this variable to disable flow shuffling and rely on + load balancing provided solely by the hash distribution. + xmit-hash-policy can be used to select the appropriate hashing for + the setup. + + The sysfs entry can be used to change the setting per bond device + and the initial value is derived from the module parameter. The + sysfs entry is allowed to be changed only if the bond device is + down. + + The default value is "1" that enables flow shuffling while value "0" + disables it. This option was added in bonding driver 3.7.1 + + +updelay + + Specifies the time, in milliseconds, to wait before enabling a + slave after a link recovery has been detected. This option is + only valid for the miimon link monitor. The updelay value + should be a multiple of the miimon value; if not, it will be + rounded down to the nearest multiple. The default value is 0. + +use_carrier + + Specifies whether or not miimon should use MII or ETHTOOL + ioctls vs. netif_carrier_ok() to determine the link + status. The MII or ETHTOOL ioctls are less efficient and + utilize a deprecated calling sequence within the kernel. The + netif_carrier_ok() relies on the device driver to maintain its + state with netif_carrier_on/off; at this writing, most, but + not all, device drivers support this facility. + + If bonding insists that the link is up when it should not be, + it may be that your network device driver does not support + netif_carrier_on/off. The default state for netif_carrier is + "carrier on," so if a driver does not support netif_carrier, + it will appear as if the link is always up. In this case, + setting use_carrier to 0 will cause bonding to revert to the + MII / ETHTOOL ioctl method to determine the link state. + + A value of 1 enables the use of netif_carrier_ok(), a value of + 0 will use the deprecated MII / ETHTOOL ioctls. The default + value is 1. + +xmit_hash_policy + + Selects the transmit hash policy to use for slave selection in + balance-xor, 802.3ad, and tlb modes. Possible values are: + + layer2 + + Uses XOR of hardware MAC addresses and packet type ID + field to generate the hash. The formula is + + hash = source MAC[5] XOR destination MAC[5] XOR packet type ID + slave number = hash modulo slave count + + This algorithm will place all traffic to a particular + network peer on the same slave. + + This algorithm is 802.3ad compliant. + + layer2+3 + + This policy uses a combination of layer2 and layer3 + protocol information to generate the hash. + + Uses XOR of hardware MAC addresses and IP addresses to + generate the hash. The formula is + + hash = source MAC[5] XOR destination MAC[5] XOR packet type ID + hash = hash XOR source IP XOR destination IP + hash = hash XOR (hash RSHIFT 16) + hash = hash XOR (hash RSHIFT 8) + And then hash is reduced modulo slave count. + + If the protocol is IPv6 then the source and destination + addresses are first hashed using ipv6_addr_hash. + + This algorithm will place all traffic to a particular + network peer on the same slave. For non-IP traffic, + the formula is the same as for the layer2 transmit + hash policy. + + This policy is intended to provide a more balanced + distribution of traffic than layer2 alone, especially + in environments where a layer3 gateway device is + required to reach most destinations. + + This algorithm is 802.3ad compliant. + + layer3+4 + + This policy uses upper layer protocol information, + when available, to generate the hash. This allows for + traffic to a particular network peer to span multiple + slaves, although a single connection will not span + multiple slaves. + + The formula for unfragmented TCP and UDP packets is + + hash = source port, destination port (as in the header) + hash = hash XOR source IP XOR destination IP + hash = hash XOR (hash RSHIFT 16) + hash = hash XOR (hash RSHIFT 8) + hash = hash RSHIFT 1 + And then hash is reduced modulo slave count. + + If the protocol is IPv6 then the source and destination + addresses are first hashed using ipv6_addr_hash. + + For fragmented TCP or UDP packets and all other IPv4 and + IPv6 protocol traffic, the source and destination port + information is omitted. For non-IP traffic, the + formula is the same as for the layer2 transmit hash + policy. + + This algorithm is not fully 802.3ad compliant. A + single TCP or UDP conversation containing both + fragmented and unfragmented packets will see packets + striped across two interfaces. This may result in out + of order delivery. Most traffic types will not meet + this criteria, as TCP rarely fragments traffic, and + most UDP traffic is not involved in extended + conversations. Other implementations of 802.3ad may + or may not tolerate this noncompliance. + + encap2+3 + + This policy uses the same formula as layer2+3 but it + relies on skb_flow_dissect to obtain the header fields + which might result in the use of inner headers if an + encapsulation protocol is used. For example this will + improve the performance for tunnel users because the + packets will be distributed according to the encapsulated + flows. + + encap3+4 + + This policy uses the same formula as layer3+4 but it + relies on skb_flow_dissect to obtain the header fields + which might result in the use of inner headers if an + encapsulation protocol is used. For example this will + improve the performance for tunnel users because the + packets will be distributed according to the encapsulated + flows. + + vlan+srcmac + + This policy uses a very rudimentary vlan ID and source mac + hash to load-balance traffic per-vlan, with failover + should one leg fail. The intended use case is for a bond + shared by multiple virtual machines, all configured to + use their own vlan, to give lacp-like functionality + without requiring lacp-capable switching hardware. + + The formula for the hash is simply + + hash = (vlan ID) XOR (source MAC vendor) XOR (source MAC dev) + + The default value is layer2. This option was added in bonding + version 2.6.3. In earlier versions of bonding, this parameter + does not exist, and the layer2 policy is the only policy. The + layer2+3 value was added for bonding version 3.2.2. + +resend_igmp + + Specifies the number of IGMP membership reports to be issued after + a failover event. One membership report is issued immediately after + the failover, subsequent packets are sent in each 200ms interval. + + The valid range is 0 - 255; the default value is 1. A value of 0 + prevents the IGMP membership report from being issued in response + to the failover event. + + This option is useful for bonding modes balance-rr (0), active-backup + (1), balance-tlb (5) and balance-alb (6), in which a failover can + switch the IGMP traffic from one slave to another. Therefore a fresh + IGMP report must be issued to cause the switch to forward the incoming + IGMP traffic over the newly selected slave. + + This option was added for bonding version 3.7.0. + +lp_interval + + Specifies the number of seconds between instances where the bonding + driver sends learning packets to each slaves peer switch. + + The valid range is 1 - 0x7fffffff; the default value is 1. This Option + has effect only in balance-tlb and balance-alb modes. + +3. Configuring Bonding Devices +============================== + +You can configure bonding using either your distro's network +initialization scripts, or manually using either iproute2 or the +sysfs interface. Distros generally use one of three packages for the +network initialization scripts: initscripts, sysconfig or interfaces. +Recent versions of these packages have support for bonding, while older +versions do not. + +We will first describe the options for configuring bonding for +distros using versions of initscripts, sysconfig and interfaces with full +or partial support for bonding, then provide information on enabling +bonding without support from the network initialization scripts (i.e., +older versions of initscripts or sysconfig). + +If you're unsure whether your distro uses sysconfig, +initscripts or interfaces, or don't know if it's new enough, have no fear. +Determining this is fairly straightforward. + +First, look for a file called interfaces in /etc/network directory. +If this file is present in your system, then your system use interfaces. See +Configuration with Interfaces Support. + +Else, issue the command:: + + $ rpm -qf /sbin/ifup + +It will respond with a line of text starting with either +"initscripts" or "sysconfig," followed by some numbers. This is the +package that provides your network initialization scripts. + +Next, to determine if your installation supports bonding, +issue the command:: + + $ grep ifenslave /sbin/ifup + +If this returns any matches, then your initscripts or +sysconfig has support for bonding. + +3.1 Configuration with Sysconfig Support +---------------------------------------- + +This section applies to distros using a version of sysconfig +with bonding support, for example, SuSE Linux Enterprise Server 9. + +SuSE SLES 9's networking configuration system does support +bonding, however, at this writing, the YaST system configuration +front end does not provide any means to work with bonding devices. +Bonding devices can be managed by hand, however, as follows. + +First, if they have not already been configured, configure the +slave devices. On SLES 9, this is most easily done by running the +yast2 sysconfig configuration utility. The goal is for to create an +ifcfg-id file for each slave device. The simplest way to accomplish +this is to configure the devices for DHCP (this is only to get the +file ifcfg-id file created; see below for some issues with DHCP). The +name of the configuration file for each device will be of the form:: + + ifcfg-id-xx:xx:xx:xx:xx:xx + +Where the "xx" portion will be replaced with the digits from +the device's permanent MAC address. + +Once the set of ifcfg-id-xx:xx:xx:xx:xx:xx files has been +created, it is necessary to edit the configuration files for the slave +devices (the MAC addresses correspond to those of the slave devices). +Before editing, the file will contain multiple lines, and will look +something like this:: + + BOOTPROTO='dhcp' + STARTMODE='on' + USERCTL='no' + UNIQUE='XNzu.WeZGOGF+4wE' + _nm_name='bus-pci-0001:61:01.0' + +Change the BOOTPROTO and STARTMODE lines to the following:: + + BOOTPROTO='none' + STARTMODE='off' + +Do not alter the UNIQUE or _nm_name lines. Remove any other +lines (USERCTL, etc). + +Once the ifcfg-id-xx:xx:xx:xx:xx:xx files have been modified, +it's time to create the configuration file for the bonding device +itself. This file is named ifcfg-bondX, where X is the number of the +bonding device to create, starting at 0. The first such file is +ifcfg-bond0, the second is ifcfg-bond1, and so on. The sysconfig +network configuration system will correctly start multiple instances +of bonding. + +The contents of the ifcfg-bondX file is as follows:: + + BOOTPROTO="static" + BROADCAST="10.0.2.255" + IPADDR="10.0.2.10" + NETMASK="255.255.0.0" + NETWORK="10.0.2.0" + REMOTE_IPADDR="" + STARTMODE="onboot" + BONDING_MASTER="yes" + BONDING_MODULE_OPTS="mode=active-backup miimon=100" + BONDING_SLAVE0="eth0" + BONDING_SLAVE1="bus-pci-0000:06:08.1" + +Replace the sample BROADCAST, IPADDR, NETMASK and NETWORK +values with the appropriate values for your network. + +The STARTMODE specifies when the device is brought online. +The possible values are: + + ======== ====================================================== + onboot The device is started at boot time. If you're not + sure, this is probably what you want. + + manual The device is started only when ifup is called + manually. Bonding devices may be configured this + way if you do not wish them to start automatically + at boot for some reason. + + hotplug The device is started by a hotplug event. This is not + a valid choice for a bonding device. + + off or The device configuration is ignored. + ignore + ======== ====================================================== + +The line BONDING_MASTER='yes' indicates that the device is a +bonding master device. The only useful value is "yes." + +The contents of BONDING_MODULE_OPTS are supplied to the +instance of the bonding module for this device. Specify the options +for the bonding mode, link monitoring, and so on here. Do not include +the max_bonds bonding parameter; this will confuse the configuration +system if you have multiple bonding devices. + +Finally, supply one BONDING_SLAVEn="slave device" for each +slave. where "n" is an increasing value, one for each slave. The +"slave device" is either an interface name, e.g., "eth0", or a device +specifier for the network device. The interface name is easier to +find, but the ethN names are subject to change at boot time if, e.g., +a device early in the sequence has failed. The device specifiers +(bus-pci-0000:06:08.1 in the example above) specify the physical +network device, and will not change unless the device's bus location +changes (for example, it is moved from one PCI slot to another). The +example above uses one of each type for demonstration purposes; most +configurations will choose one or the other for all slave devices. + +When all configuration files have been modified or created, +networking must be restarted for the configuration changes to take +effect. This can be accomplished via the following:: + + # /etc/init.d/network restart + +Note that the network control script (/sbin/ifdown) will +remove the bonding module as part of the network shutdown processing, +so it is not necessary to remove the module by hand if, e.g., the +module parameters have changed. + +Also, at this writing, YaST/YaST2 will not manage bonding +devices (they do not show bonding interfaces on its list of network +devices). It is necessary to edit the configuration file by hand to +change the bonding configuration. + +Additional general options and details of the ifcfg file +format can be found in an example ifcfg template file:: + + /etc/sysconfig/network/ifcfg.template + +Note that the template does not document the various ``BONDING_*`` +settings described above, but does describe many of the other options. + +3.1.1 Using DHCP with Sysconfig +------------------------------- + +Under sysconfig, configuring a device with BOOTPROTO='dhcp' +will cause it to query DHCP for its IP address information. At this +writing, this does not function for bonding devices; the scripts +attempt to obtain the device address from DHCP prior to adding any of +the slave devices. Without active slaves, the DHCP requests are not +sent to the network. + +3.1.2 Configuring Multiple Bonds with Sysconfig +----------------------------------------------- + +The sysconfig network initialization system is capable of +handling multiple bonding devices. All that is necessary is for each +bonding instance to have an appropriately configured ifcfg-bondX file +(as described above). Do not specify the "max_bonds" parameter to any +instance of bonding, as this will confuse sysconfig. If you require +multiple bonding devices with identical parameters, create multiple +ifcfg-bondX files. + +Because the sysconfig scripts supply the bonding module +options in the ifcfg-bondX file, it is not necessary to add them to +the system ``/etc/modules.d/*.conf`` configuration files. + +3.2 Configuration with Initscripts Support +------------------------------------------ + +This section applies to distros using a recent version of +initscripts with bonding support, for example, Red Hat Enterprise Linux +version 3 or later, Fedora, etc. On these systems, the network +initialization scripts have knowledge of bonding, and can be configured to +control bonding devices. Note that older versions of the initscripts +package have lower levels of support for bonding; this will be noted where +applicable. + +These distros will not automatically load the network adapter +driver unless the ethX device is configured with an IP address. +Because of this constraint, users must manually configure a +network-script file for all physical adapters that will be members of +a bondX link. Network script files are located in the directory: + +/etc/sysconfig/network-scripts + +The file name must be prefixed with "ifcfg-eth" and suffixed +with the adapter's physical adapter number. For example, the script +for eth0 would be named /etc/sysconfig/network-scripts/ifcfg-eth0. +Place the following text in the file:: + + DEVICE=eth0 + USERCTL=no + ONBOOT=yes + MASTER=bond0 + SLAVE=yes + BOOTPROTO=none + +The DEVICE= line will be different for every ethX device and +must correspond with the name of the file, i.e., ifcfg-eth1 must have +a device line of DEVICE=eth1. The setting of the MASTER= line will +also depend on the final bonding interface name chosen for your bond. +As with other network devices, these typically start at 0, and go up +one for each device, i.e., the first bonding instance is bond0, the +second is bond1, and so on. + +Next, create a bond network script. The file name for this +script will be /etc/sysconfig/network-scripts/ifcfg-bondX where X is +the number of the bond. For bond0 the file is named "ifcfg-bond0", +for bond1 it is named "ifcfg-bond1", and so on. Within that file, +place the following text:: + + DEVICE=bond0 + IPADDR=192.168.1.1 + NETMASK=255.255.255.0 + NETWORK=192.168.1.0 + BROADCAST=192.168.1.255 + ONBOOT=yes + BOOTPROTO=none + USERCTL=no + +Be sure to change the networking specific lines (IPADDR, +NETMASK, NETWORK and BROADCAST) to match your network configuration. + +For later versions of initscripts, such as that found with Fedora +7 (or later) and Red Hat Enterprise Linux version 5 (or later), it is possible, +and, indeed, preferable, to specify the bonding options in the ifcfg-bond0 +file, e.g. a line of the format:: + + BONDING_OPTS="mode=active-backup arp_interval=60 arp_ip_target=192.168.1.254" + +will configure the bond with the specified options. The options +specified in BONDING_OPTS are identical to the bonding module parameters +except for the arp_ip_target field when using versions of initscripts older +than and 8.57 (Fedora 8) and 8.45.19 (Red Hat Enterprise Linux 5.2). When +using older versions each target should be included as a separate option and +should be preceded by a '+' to indicate it should be added to the list of +queried targets, e.g.,:: + + arp_ip_target=+192.168.1.1 arp_ip_target=+192.168.1.2 + +is the proper syntax to specify multiple targets. When specifying +options via BONDING_OPTS, it is not necessary to edit +``/etc/modprobe.d/*.conf``. + +For even older versions of initscripts that do not support +BONDING_OPTS, it is necessary to edit /etc/modprobe.d/*.conf, depending upon +your distro) to load the bonding module with your desired options when the +bond0 interface is brought up. The following lines in /etc/modprobe.d/*.conf +will load the bonding module, and select its options: + + alias bond0 bonding + options bond0 mode=balance-alb miimon=100 + +Replace the sample parameters with the appropriate set of +options for your configuration. + +Finally run "/etc/rc.d/init.d/network restart" as root. This +will restart the networking subsystem and your bond link should be now +up and running. + +3.2.1 Using DHCP with Initscripts +--------------------------------- + +Recent versions of initscripts (the versions supplied with Fedora +Core 3 and Red Hat Enterprise Linux 4, or later versions, are reported to +work) have support for assigning IP information to bonding devices via +DHCP. + +To configure bonding for DHCP, configure it as described +above, except replace the line "BOOTPROTO=none" with "BOOTPROTO=dhcp" +and add a line consisting of "TYPE=Bonding". Note that the TYPE value +is case sensitive. + +3.2.2 Configuring Multiple Bonds with Initscripts +------------------------------------------------- + +Initscripts packages that are included with Fedora 7 and Red Hat +Enterprise Linux 5 support multiple bonding interfaces by simply +specifying the appropriate BONDING_OPTS= in ifcfg-bondX where X is the +number of the bond. This support requires sysfs support in the kernel, +and a bonding driver of version 3.0.0 or later. Other configurations may +not support this method for specifying multiple bonding interfaces; for +those instances, see the "Configuring Multiple Bonds Manually" section, +below. + +3.3 Configuring Bonding Manually with iproute2 +----------------------------------------------- + +This section applies to distros whose network initialization +scripts (the sysconfig or initscripts package) do not have specific +knowledge of bonding. One such distro is SuSE Linux Enterprise Server +version 8. + +The general method for these systems is to place the bonding +module parameters into a config file in /etc/modprobe.d/ (as +appropriate for the installed distro), then add modprobe and/or +`ip link` commands to the system's global init script. The name of +the global init script differs; for sysconfig, it is +/etc/init.d/boot.local and for initscripts it is /etc/rc.d/rc.local. + +For example, if you wanted to make a simple bond of two e100 +devices (presumed to be eth0 and eth1), and have it persist across +reboots, edit the appropriate file (/etc/init.d/boot.local or +/etc/rc.d/rc.local), and add the following:: + + modprobe bonding mode=balance-alb miimon=100 + modprobe e100 + ifconfig bond0 192.168.1.1 netmask 255.255.255.0 up + ip link set eth0 master bond0 + ip link set eth1 master bond0 + +Replace the example bonding module parameters and bond0 +network configuration (IP address, netmask, etc) with the appropriate +values for your configuration. + +Unfortunately, this method will not provide support for the +ifup and ifdown scripts on the bond devices. To reload the bonding +configuration, it is necessary to run the initialization script, e.g.,:: + + # /etc/init.d/boot.local + +or:: + + # /etc/rc.d/rc.local + +It may be desirable in such a case to create a separate script +which only initializes the bonding configuration, then call that +separate script from within boot.local. This allows for bonding to be +enabled without re-running the entire global init script. + +To shut down the bonding devices, it is necessary to first +mark the bonding device itself as being down, then remove the +appropriate device driver modules. For our example above, you can do +the following:: + + # ifconfig bond0 down + # rmmod bonding + # rmmod e100 + +Again, for convenience, it may be desirable to create a script +with these commands. + + +3.3.1 Configuring Multiple Bonds Manually +----------------------------------------- + +This section contains information on configuring multiple +bonding devices with differing options for those systems whose network +initialization scripts lack support for configuring multiple bonds. + +If you require multiple bonding devices, but all with the same +options, you may wish to use the "max_bonds" module parameter, +documented above. + +To create multiple bonding devices with differing options, it is +preferable to use bonding parameters exported by sysfs, documented in the +section below. + +For versions of bonding without sysfs support, the only means to +provide multiple instances of bonding with differing options is to load +the bonding driver multiple times. Note that current versions of the +sysconfig network initialization scripts handle this automatically; if +your distro uses these scripts, no special action is needed. See the +section Configuring Bonding Devices, above, if you're not sure about your +network initialization scripts. + +To load multiple instances of the module, it is necessary to +specify a different name for each instance (the module loading system +requires that every loaded module, even multiple instances of the same +module, have a unique name). This is accomplished by supplying multiple +sets of bonding options in ``/etc/modprobe.d/*.conf``, for example:: + + alias bond0 bonding + options bond0 -o bond0 mode=balance-rr miimon=100 + + alias bond1 bonding + options bond1 -o bond1 mode=balance-alb miimon=50 + +will load the bonding module two times. The first instance is +named "bond0" and creates the bond0 device in balance-rr mode with an +miimon of 100. The second instance is named "bond1" and creates the +bond1 device in balance-alb mode with an miimon of 50. + +In some circumstances (typically with older distributions), +the above does not work, and the second bonding instance never sees +its options. In that case, the second options line can be substituted +as follows:: + + install bond1 /sbin/modprobe --ignore-install bonding -o bond1 \ + mode=balance-alb miimon=50 + +This may be repeated any number of times, specifying a new and +unique name in place of bond1 for each subsequent instance. + +It has been observed that some Red Hat supplied kernels are unable +to rename modules at load time (the "-o bond1" part). Attempts to pass +that option to modprobe will produce an "Operation not permitted" error. +This has been reported on some Fedora Core kernels, and has been seen on +RHEL 4 as well. On kernels exhibiting this problem, it will be impossible +to configure multiple bonds with differing parameters (as they are older +kernels, and also lack sysfs support). + +3.4 Configuring Bonding Manually via Sysfs +------------------------------------------ + +Starting with version 3.0.0, Channel Bonding may be configured +via the sysfs interface. This interface allows dynamic configuration +of all bonds in the system without unloading the module. It also +allows for adding and removing bonds at runtime. Ifenslave is no +longer required, though it is still supported. + +Use of the sysfs interface allows you to use multiple bonds +with different configurations without having to reload the module. +It also allows you to use multiple, differently configured bonds when +bonding is compiled into the kernel. + +You must have the sysfs filesystem mounted to configure +bonding this way. The examples in this document assume that you +are using the standard mount point for sysfs, e.g. /sys. If your +sysfs filesystem is mounted elsewhere, you will need to adjust the +example paths accordingly. + +Creating and Destroying Bonds +----------------------------- +To add a new bond foo:: + + # echo +foo > /sys/class/net/bonding_masters + +To remove an existing bond bar:: + + # echo -bar > /sys/class/net/bonding_masters + +To show all existing bonds:: + + # cat /sys/class/net/bonding_masters + +.. note:: + + due to 4K size limitation of sysfs files, this list may be + truncated if you have more than a few hundred bonds. This is unlikely + to occur under normal operating conditions. + +Adding and Removing Slaves +-------------------------- +Interfaces may be enslaved to a bond using the file +/sys/class/net/<bond>/bonding/slaves. The semantics for this file +are the same as for the bonding_masters file. + +To enslave interface eth0 to bond bond0:: + + # ifconfig bond0 up + # echo +eth0 > /sys/class/net/bond0/bonding/slaves + +To free slave eth0 from bond bond0:: + + # echo -eth0 > /sys/class/net/bond0/bonding/slaves + +When an interface is enslaved to a bond, symlinks between the +two are created in the sysfs filesystem. In this case, you would get +/sys/class/net/bond0/slave_eth0 pointing to /sys/class/net/eth0, and +/sys/class/net/eth0/master pointing to /sys/class/net/bond0. + +This means that you can tell quickly whether or not an +interface is enslaved by looking for the master symlink. Thus: +# echo -eth0 > /sys/class/net/eth0/master/bonding/slaves +will free eth0 from whatever bond it is enslaved to, regardless of +the name of the bond interface. + +Changing a Bond's Configuration +------------------------------- +Each bond may be configured individually by manipulating the +files located in /sys/class/net/<bond name>/bonding + +The names of these files correspond directly with the command- +line parameters described elsewhere in this file, and, with the +exception of arp_ip_target, they accept the same values. To see the +current setting, simply cat the appropriate file. + +A few examples will be given here; for specific usage +guidelines for each parameter, see the appropriate section in this +document. + +To configure bond0 for balance-alb mode:: + + # ifconfig bond0 down + # echo 6 > /sys/class/net/bond0/bonding/mode + - or - + # echo balance-alb > /sys/class/net/bond0/bonding/mode + +.. note:: + + The bond interface must be down before the mode can be changed. + +To enable MII monitoring on bond0 with a 1 second interval:: + + # echo 1000 > /sys/class/net/bond0/bonding/miimon + +.. note:: + + If ARP monitoring is enabled, it will disabled when MII + monitoring is enabled, and vice-versa. + +To add ARP targets:: + + # echo +192.168.0.100 > /sys/class/net/bond0/bonding/arp_ip_target + # echo +192.168.0.101 > /sys/class/net/bond0/bonding/arp_ip_target + +.. note:: + + up to 16 target addresses may be specified. + +To remove an ARP target:: + + # echo -192.168.0.100 > /sys/class/net/bond0/bonding/arp_ip_target + +To configure the interval between learning packet transmits:: + + # echo 12 > /sys/class/net/bond0/bonding/lp_interval + +.. note:: + + the lp_interval is the number of seconds between instances where + the bonding driver sends learning packets to each slaves peer switch. The + default interval is 1 second. + +Example Configuration +--------------------- +We begin with the same example that is shown in section 3.3, +executed with sysfs, and without using ifenslave. + +To make a simple bond of two e100 devices (presumed to be eth0 +and eth1), and have it persist across reboots, edit the appropriate +file (/etc/init.d/boot.local or /etc/rc.d/rc.local), and add the +following:: + + modprobe bonding + modprobe e100 + echo balance-alb > /sys/class/net/bond0/bonding/mode + ifconfig bond0 192.168.1.1 netmask 255.255.255.0 up + echo 100 > /sys/class/net/bond0/bonding/miimon + echo +eth0 > /sys/class/net/bond0/bonding/slaves + echo +eth1 > /sys/class/net/bond0/bonding/slaves + +To add a second bond, with two e1000 interfaces in +active-backup mode, using ARP monitoring, add the following lines to +your init script:: + + modprobe e1000 + echo +bond1 > /sys/class/net/bonding_masters + echo active-backup > /sys/class/net/bond1/bonding/mode + ifconfig bond1 192.168.2.1 netmask 255.255.255.0 up + echo +192.168.2.100 /sys/class/net/bond1/bonding/arp_ip_target + echo 2000 > /sys/class/net/bond1/bonding/arp_interval + echo +eth2 > /sys/class/net/bond1/bonding/slaves + echo +eth3 > /sys/class/net/bond1/bonding/slaves + +3.5 Configuration with Interfaces Support +----------------------------------------- + +This section applies to distros which use /etc/network/interfaces file +to describe network interface configuration, most notably Debian and its +derivatives. + +The ifup and ifdown commands on Debian don't support bonding out of +the box. The ifenslave-2.6 package should be installed to provide bonding +support. Once installed, this package will provide ``bond-*`` options +to be used into /etc/network/interfaces. + +Note that ifenslave-2.6 package will load the bonding module and use +the ifenslave command when appropriate. + +Example Configurations +---------------------- + +In /etc/network/interfaces, the following stanza will configure bond0, in +active-backup mode, with eth0 and eth1 as slaves:: + + auto bond0 + iface bond0 inet dhcp + bond-slaves eth0 eth1 + bond-mode active-backup + bond-miimon 100 + bond-primary eth0 eth1 + +If the above configuration doesn't work, you might have a system using +upstart for system startup. This is most notably true for recent +Ubuntu versions. The following stanza in /etc/network/interfaces will +produce the same result on those systems:: + + auto bond0 + iface bond0 inet dhcp + bond-slaves none + bond-mode active-backup + bond-miimon 100 + + auto eth0 + iface eth0 inet manual + bond-master bond0 + bond-primary eth0 eth1 + + auto eth1 + iface eth1 inet manual + bond-master bond0 + bond-primary eth0 eth1 + +For a full list of ``bond-*`` supported options in /etc/network/interfaces and +some more advanced examples tailored to you particular distros, see the files in +/usr/share/doc/ifenslave-2.6. + +3.6 Overriding Configuration for Special Cases +---------------------------------------------- + +When using the bonding driver, the physical port which transmits a frame is +typically selected by the bonding driver, and is not relevant to the user or +system administrator. The output port is simply selected using the policies of +the selected bonding mode. On occasion however, it is helpful to direct certain +classes of traffic to certain physical interfaces on output to implement +slightly more complex policies. For example, to reach a web server over a +bonded interface in which eth0 connects to a private network, while eth1 +connects via a public network, it may be desirous to bias the bond to send said +traffic over eth0 first, using eth1 only as a fall back, while all other traffic +can safely be sent over either interface. Such configurations may be achieved +using the traffic control utilities inherent in linux. + +By default the bonding driver is multiqueue aware and 16 queues are created +when the driver initializes (see Documentation/networking/multiqueue.rst +for details). If more or less queues are desired the module parameter +tx_queues can be used to change this value. There is no sysfs parameter +available as the allocation is done at module init time. + +The output of the file /proc/net/bonding/bondX has changed so the output Queue +ID is now printed for each slave:: + + Bonding Mode: fault-tolerance (active-backup) + Primary Slave: None + Currently Active Slave: eth0 + MII Status: up + MII Polling Interval (ms): 0 + Up Delay (ms): 0 + Down Delay (ms): 0 + + Slave Interface: eth0 + MII Status: up + Link Failure Count: 0 + Permanent HW addr: 00:1a:a0:12:8f:cb + Slave queue ID: 0 + + Slave Interface: eth1 + MII Status: up + Link Failure Count: 0 + Permanent HW addr: 00:1a:a0:12:8f:cc + Slave queue ID: 2 + +The queue_id for a slave can be set using the command:: + + # echo "eth1:2" > /sys/class/net/bond0/bonding/queue_id + +Any interface that needs a queue_id set should set it with multiple calls +like the one above until proper priorities are set for all interfaces. On +distributions that allow configuration via initscripts, multiple 'queue_id' +arguments can be added to BONDING_OPTS to set all needed slave queues. + +These queue id's can be used in conjunction with the tc utility to configure +a multiqueue qdisc and filters to bias certain traffic to transmit on certain +slave devices. For instance, say we wanted, in the above configuration to +force all traffic bound to 192.168.1.100 to use eth1 in the bond as its output +device. The following commands would accomplish this:: + + # tc qdisc add dev bond0 handle 1 root multiq + + # tc filter add dev bond0 protocol ip parent 1: prio 1 u32 match ip \ + dst 192.168.1.100 action skbedit queue_mapping 2 + +These commands tell the kernel to attach a multiqueue queue discipline to the +bond0 interface and filter traffic enqueued to it, such that packets with a dst +ip of 192.168.1.100 have their output queue mapping value overwritten to 2. +This value is then passed into the driver, causing the normal output path +selection policy to be overridden, selecting instead qid 2, which maps to eth1. + +Note that qid values begin at 1. Qid 0 is reserved to initiate to the driver +that normal output policy selection should take place. One benefit to simply +leaving the qid for a slave to 0 is the multiqueue awareness in the bonding +driver that is now present. This awareness allows tc filters to be placed on +slave devices as well as bond devices and the bonding driver will simply act as +a pass-through for selecting output queues on the slave device rather than +output port selection. + +This feature first appeared in bonding driver version 3.7.0 and support for +output slave selection was limited to round-robin and active-backup modes. + +3.7 Configuring LACP for 802.3ad mode in a more secure way +---------------------------------------------------------- + +When using 802.3ad bonding mode, the Actor (host) and Partner (switch) +exchange LACPDUs. These LACPDUs cannot be sniffed, because they are +destined to link local mac addresses (which switches/bridges are not +supposed to forward). However, most of the values are easily predictable +or are simply the machine's MAC address (which is trivially known to all +other hosts in the same L2). This implies that other machines in the L2 +domain can spoof LACPDU packets from other hosts to the switch and potentially +cause mayhem by joining (from the point of view of the switch) another +machine's aggregate, thus receiving a portion of that hosts incoming +traffic and / or spoofing traffic from that machine themselves (potentially +even successfully terminating some portion of flows). Though this is not +a likely scenario, one could avoid this possibility by simply configuring +few bonding parameters: + + (a) ad_actor_system : You can set a random mac-address that can be used for + these LACPDU exchanges. The value can not be either NULL or Multicast. + Also it's preferable to set the local-admin bit. Following shell code + generates a random mac-address as described above:: + + # sys_mac_addr=$(printf '%02x:%02x:%02x:%02x:%02x:%02x' \ + $(( (RANDOM & 0xFE) | 0x02 )) \ + $(( RANDOM & 0xFF )) \ + $(( RANDOM & 0xFF )) \ + $(( RANDOM & 0xFF )) \ + $(( RANDOM & 0xFF )) \ + $(( RANDOM & 0xFF ))) + # echo $sys_mac_addr > /sys/class/net/bond0/bonding/ad_actor_system + + (b) ad_actor_sys_prio : Randomize the system priority. The default value + is 65535, but system can take the value from 1 - 65535. Following shell + code generates random priority and sets it:: + + # sys_prio=$(( 1 + RANDOM + RANDOM )) + # echo $sys_prio > /sys/class/net/bond0/bonding/ad_actor_sys_prio + + (c) ad_user_port_key : Use the user portion of the port-key. The default + keeps this empty. These are the upper 10 bits of the port-key and value + ranges from 0 - 1023. Following shell code generates these 10 bits and + sets it:: + + # usr_port_key=$(( RANDOM & 0x3FF )) + # echo $usr_port_key > /sys/class/net/bond0/bonding/ad_user_port_key + + +4 Querying Bonding Configuration +================================= + +4.1 Bonding Configuration +------------------------- + +Each bonding device has a read-only file residing in the +/proc/net/bonding directory. The file contents include information +about the bonding configuration, options and state of each slave. + +For example, the contents of /proc/net/bonding/bond0 after the +driver is loaded with parameters of mode=0 and miimon=1000 is +generally as follows:: + + Ethernet Channel Bonding Driver: 2.6.1 (October 29, 2004) + Bonding Mode: load balancing (round-robin) + Currently Active Slave: eth0 + MII Status: up + MII Polling Interval (ms): 1000 + Up Delay (ms): 0 + Down Delay (ms): 0 + + Slave Interface: eth1 + MII Status: up + Link Failure Count: 1 + + Slave Interface: eth0 + MII Status: up + Link Failure Count: 1 + +The precise format and contents will change depending upon the +bonding configuration, state, and version of the bonding driver. + +4.2 Network configuration +------------------------- + +The network configuration can be inspected using the ifconfig +command. Bonding devices will have the MASTER flag set; Bonding slave +devices will have the SLAVE flag set. The ifconfig output does not +contain information on which slaves are associated with which masters. + +In the example below, the bond0 interface is the master +(MASTER) while eth0 and eth1 are slaves (SLAVE). Notice all slaves of +bond0 have the same MAC address (HWaddr) as bond0 for all modes except +TLB and ALB that require a unique MAC address for each slave:: + + # /sbin/ifconfig + bond0 Link encap:Ethernet HWaddr 00:C0:F0:1F:37:B4 + inet addr:XXX.XXX.XXX.YYY Bcast:XXX.XXX.XXX.255 Mask:255.255.252.0 + UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1 + RX packets:7224794 errors:0 dropped:0 overruns:0 frame:0 + TX packets:3286647 errors:1 dropped:0 overruns:1 carrier:0 + collisions:0 txqueuelen:0 + + eth0 Link encap:Ethernet HWaddr 00:C0:F0:1F:37:B4 + UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1 + RX packets:3573025 errors:0 dropped:0 overruns:0 frame:0 + TX packets:1643167 errors:1 dropped:0 overruns:1 carrier:0 + collisions:0 txqueuelen:100 + Interrupt:10 Base address:0x1080 + + eth1 Link encap:Ethernet HWaddr 00:C0:F0:1F:37:B4 + UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1 + RX packets:3651769 errors:0 dropped:0 overruns:0 frame:0 + TX packets:1643480 errors:0 dropped:0 overruns:0 carrier:0 + collisions:0 txqueuelen:100 + Interrupt:9 Base address:0x1400 + +5. Switch Configuration +======================= + +For this section, "switch" refers to whatever system the +bonded devices are directly connected to (i.e., where the other end of +the cable plugs into). This may be an actual dedicated switch device, +or it may be another regular system (e.g., another computer running +Linux), + +The active-backup, balance-tlb and balance-alb modes do not +require any specific configuration of the switch. + +The 802.3ad mode requires that the switch have the appropriate +ports configured as an 802.3ad aggregation. The precise method used +to configure this varies from switch to switch, but, for example, a +Cisco 3550 series switch requires that the appropriate ports first be +grouped together in a single etherchannel instance, then that +etherchannel is set to mode "lacp" to enable 802.3ad (instead of +standard EtherChannel). + +The balance-rr, balance-xor and broadcast modes generally +require that the switch have the appropriate ports grouped together. +The nomenclature for such a group differs between switches, it may be +called an "etherchannel" (as in the Cisco example, above), a "trunk +group" or some other similar variation. For these modes, each switch +will also have its own configuration options for the switch's transmit +policy to the bond. Typical choices include XOR of either the MAC or +IP addresses. The transmit policy of the two peers does not need to +match. For these three modes, the bonding mode really selects a +transmit policy for an EtherChannel group; all three will interoperate +with another EtherChannel group. + + +6. 802.1q VLAN Support +====================== + +It is possible to configure VLAN devices over a bond interface +using the 8021q driver. However, only packets coming from the 8021q +driver and passing through bonding will be tagged by default. Self +generated packets, for example, bonding's learning packets or ARP +packets generated by either ALB mode or the ARP monitor mechanism, are +tagged internally by bonding itself. As a result, bonding must +"learn" the VLAN IDs configured above it, and use those IDs to tag +self generated packets. + +For reasons of simplicity, and to support the use of adapters +that can do VLAN hardware acceleration offloading, the bonding +interface declares itself as fully hardware offloading capable, it gets +the add_vid/kill_vid notifications to gather the necessary +information, and it propagates those actions to the slaves. In case +of mixed adapter types, hardware accelerated tagged packets that +should go through an adapter that is not offloading capable are +"un-accelerated" by the bonding driver so the VLAN tag sits in the +regular location. + +VLAN interfaces *must* be added on top of a bonding interface +only after enslaving at least one slave. The bonding interface has a +hardware address of 00:00:00:00:00:00 until the first slave is added. +If the VLAN interface is created prior to the first enslavement, it +would pick up the all-zeroes hardware address. Once the first slave +is attached to the bond, the bond device itself will pick up the +slave's hardware address, which is then available for the VLAN device. + +Also, be aware that a similar problem can occur if all slaves +are released from a bond that still has one or more VLAN interfaces on +top of it. When a new slave is added, the bonding interface will +obtain its hardware address from the first slave, which might not +match the hardware address of the VLAN interfaces (which was +ultimately copied from an earlier slave). + +There are two methods to insure that the VLAN device operates +with the correct hardware address if all slaves are removed from a +bond interface: + +1. Remove all VLAN interfaces then recreate them + +2. Set the bonding interface's hardware address so that it +matches the hardware address of the VLAN interfaces. + +Note that changing a VLAN interface's HW address would set the +underlying device -- i.e. the bonding interface -- to promiscuous +mode, which might not be what you want. + + +7. Link Monitoring +================== + +The bonding driver at present supports two schemes for +monitoring a slave device's link state: the ARP monitor and the MII +monitor. + +At the present time, due to implementation restrictions in the +bonding driver itself, it is not possible to enable both ARP and MII +monitoring simultaneously. + +7.1 ARP Monitor Operation +------------------------- + +The ARP monitor operates as its name suggests: it sends ARP +queries to one or more designated peer systems on the network, and +uses the response as an indication that the link is operating. This +gives some assurance that traffic is actually flowing to and from one +or more peers on the local network. + +7.2 Configuring Multiple ARP Targets +------------------------------------ + +While ARP monitoring can be done with just one target, it can +be useful in a High Availability setup to have several targets to +monitor. In the case of just one target, the target itself may go +down or have a problem making it unresponsive to ARP requests. Having +an additional target (or several) increases the reliability of the ARP +monitoring. + +Multiple ARP targets must be separated by commas as follows:: + + # example options for ARP monitoring with three targets + alias bond0 bonding + options bond0 arp_interval=60 arp_ip_target=192.168.0.1,192.168.0.3,192.168.0.9 + +For just a single target the options would resemble:: + + # example options for ARP monitoring with one target + alias bond0 bonding + options bond0 arp_interval=60 arp_ip_target=192.168.0.100 + + +7.3 MII Monitor Operation +------------------------- + +The MII monitor monitors only the carrier state of the local +network interface. It accomplishes this in one of three ways: by +depending upon the device driver to maintain its carrier state, by +querying the device's MII registers, or by making an ethtool query to +the device. + +If the use_carrier module parameter is 1 (the default value), +then the MII monitor will rely on the driver for carrier state +information (via the netif_carrier subsystem). As explained in the +use_carrier parameter information, above, if the MII monitor fails to +detect carrier loss on the device (e.g., when the cable is physically +disconnected), it may be that the driver does not support +netif_carrier. + +If use_carrier is 0, then the MII monitor will first query the +device's (via ioctl) MII registers and check the link state. If that +request fails (not just that it returns carrier down), then the MII +monitor will make an ethtool ETHTOOL_GLINK request to attempt to obtain +the same information. If both methods fail (i.e., the driver either +does not support or had some error in processing both the MII register +and ethtool requests), then the MII monitor will assume the link is +up. + +8. Potential Sources of Trouble +=============================== + +8.1 Adventures in Routing +------------------------- + +When bonding is configured, it is important that the slave +devices not have routes that supersede routes of the master (or, +generally, not have routes at all). For example, suppose the bonding +device bond0 has two slaves, eth0 and eth1, and the routing table is +as follows:: + + Kernel IP routing table + Destination Gateway Genmask Flags MSS Window irtt Iface + 10.0.0.0 0.0.0.0 255.255.0.0 U 40 0 0 eth0 + 10.0.0.0 0.0.0.0 255.255.0.0 U 40 0 0 eth1 + 10.0.0.0 0.0.0.0 255.255.0.0 U 40 0 0 bond0 + 127.0.0.0 0.0.0.0 255.0.0.0 U 40 0 0 lo + +This routing configuration will likely still update the +receive/transmit times in the driver (needed by the ARP monitor), but +may bypass the bonding driver (because outgoing traffic to, in this +case, another host on network 10 would use eth0 or eth1 before bond0). + +The ARP monitor (and ARP itself) may become confused by this +configuration, because ARP requests (generated by the ARP monitor) +will be sent on one interface (bond0), but the corresponding reply +will arrive on a different interface (eth0). This reply looks to ARP +as an unsolicited ARP reply (because ARP matches replies on an +interface basis), and is discarded. The MII monitor is not affected +by the state of the routing table. + +The solution here is simply to insure that slaves do not have +routes of their own, and if for some reason they must, those routes do +not supersede routes of their master. This should generally be the +case, but unusual configurations or errant manual or automatic static +route additions may cause trouble. + +8.2 Ethernet Device Renaming +---------------------------- + +On systems with network configuration scripts that do not +associate physical devices directly with network interface names (so +that the same physical device always has the same "ethX" name), it may +be necessary to add some special logic to config files in +/etc/modprobe.d/. + +For example, given a modules.conf containing the following:: + + alias bond0 bonding + options bond0 mode=some-mode miimon=50 + alias eth0 tg3 + alias eth1 tg3 + alias eth2 e1000 + alias eth3 e1000 + +If neither eth0 and eth1 are slaves to bond0, then when the +bond0 interface comes up, the devices may end up reordered. This +happens because bonding is loaded first, then its slave device's +drivers are loaded next. Since no other drivers have been loaded, +when the e1000 driver loads, it will receive eth0 and eth1 for its +devices, but the bonding configuration tries to enslave eth2 and eth3 +(which may later be assigned to the tg3 devices). + +Adding the following:: + + add above bonding e1000 tg3 + +causes modprobe to load e1000 then tg3, in that order, when +bonding is loaded. This command is fully documented in the +modules.conf manual page. + +On systems utilizing modprobe an equivalent problem can occur. +In this case, the following can be added to config files in +/etc/modprobe.d/ as:: + + softdep bonding pre: tg3 e1000 + +This will load tg3 and e1000 modules before loading the bonding one. +Full documentation on this can be found in the modprobe.d and modprobe +manual pages. + +8.3. Painfully Slow Or No Failed Link Detection By Miimon +--------------------------------------------------------- + +By default, bonding enables the use_carrier option, which +instructs bonding to trust the driver to maintain carrier state. + +As discussed in the options section, above, some drivers do +not support the netif_carrier_on/_off link state tracking system. +With use_carrier enabled, bonding will always see these links as up, +regardless of their actual state. + +Additionally, other drivers do support netif_carrier, but do +not maintain it in real time, e.g., only polling the link state at +some fixed interval. In this case, miimon will detect failures, but +only after some long period of time has expired. If it appears that +miimon is very slow in detecting link failures, try specifying +use_carrier=0 to see if that improves the failure detection time. If +it does, then it may be that the driver checks the carrier state at a +fixed interval, but does not cache the MII register values (so the +use_carrier=0 method of querying the registers directly works). If +use_carrier=0 does not improve the failover, then the driver may cache +the registers, or the problem may be elsewhere. + +Also, remember that miimon only checks for the device's +carrier state. It has no way to determine the state of devices on or +beyond other ports of a switch, or if a switch is refusing to pass +traffic while still maintaining carrier on. + +9. SNMP agents +=============== + +If running SNMP agents, the bonding driver should be loaded +before any network drivers participating in a bond. This requirement +is due to the interface index (ipAdEntIfIndex) being associated to +the first interface found with a given IP address. That is, there is +only one ipAdEntIfIndex for each IP address. For example, if eth0 and +eth1 are slaves of bond0 and the driver for eth0 is loaded before the +bonding driver, the interface for the IP address will be associated +with the eth0 interface. This configuration is shown below, the IP +address 192.168.1.1 has an interface index of 2 which indexes to eth0 +in the ifDescr table (ifDescr.2). + +:: + + interfaces.ifTable.ifEntry.ifDescr.1 = lo + interfaces.ifTable.ifEntry.ifDescr.2 = eth0 + interfaces.ifTable.ifEntry.ifDescr.3 = eth1 + interfaces.ifTable.ifEntry.ifDescr.4 = eth2 + interfaces.ifTable.ifEntry.ifDescr.5 = eth3 + interfaces.ifTable.ifEntry.ifDescr.6 = bond0 + ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.10.10.10.10 = 5 + ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.192.168.1.1 = 2 + ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.10.74.20.94 = 4 + ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.127.0.0.1 = 1 + +This problem is avoided by loading the bonding driver before +any network drivers participating in a bond. Below is an example of +loading the bonding driver first, the IP address 192.168.1.1 is +correctly associated with ifDescr.2. + + interfaces.ifTable.ifEntry.ifDescr.1 = lo + interfaces.ifTable.ifEntry.ifDescr.2 = bond0 + interfaces.ifTable.ifEntry.ifDescr.3 = eth0 + interfaces.ifTable.ifEntry.ifDescr.4 = eth1 + interfaces.ifTable.ifEntry.ifDescr.5 = eth2 + interfaces.ifTable.ifEntry.ifDescr.6 = eth3 + ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.10.10.10.10 = 6 + ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.192.168.1.1 = 2 + ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.10.74.20.94 = 5 + ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.127.0.0.1 = 1 + +While some distributions may not report the interface name in +ifDescr, the association between the IP address and IfIndex remains +and SNMP functions such as Interface_Scan_Next will report that +association. + +10. Promiscuous mode +==================== + +When running network monitoring tools, e.g., tcpdump, it is +common to enable promiscuous mode on the device, so that all traffic +is seen (instead of seeing only traffic destined for the local host). +The bonding driver handles promiscuous mode changes to the bonding +master device (e.g., bond0), and propagates the setting to the slave +devices. + +For the balance-rr, balance-xor, broadcast, and 802.3ad modes, +the promiscuous mode setting is propagated to all slaves. + +For the active-backup, balance-tlb and balance-alb modes, the +promiscuous mode setting is propagated only to the active slave. + +For balance-tlb mode, the active slave is the slave currently +receiving inbound traffic. + +For balance-alb mode, the active slave is the slave used as a +"primary." This slave is used for mode-specific control traffic, for +sending to peers that are unassigned or if the load is unbalanced. + +For the active-backup, balance-tlb and balance-alb modes, when +the active slave changes (e.g., due to a link failure), the +promiscuous setting will be propagated to the new active slave. + +11. Configuring Bonding for High Availability +============================================= + +High Availability refers to configurations that provide +maximum network availability by having redundant or backup devices, +links or switches between the host and the rest of the world. The +goal is to provide the maximum availability of network connectivity +(i.e., the network always works), even though other configurations +could provide higher throughput. + +11.1 High Availability in a Single Switch Topology +-------------------------------------------------- + +If two hosts (or a host and a single switch) are directly +connected via multiple physical links, then there is no availability +penalty to optimizing for maximum bandwidth. In this case, there is +only one switch (or peer), so if it fails, there is no alternative +access to fail over to. Additionally, the bonding load balance modes +support link monitoring of their members, so if individual links fail, +the load will be rebalanced across the remaining devices. + +See Section 12, "Configuring Bonding for Maximum Throughput" +for information on configuring bonding with one peer device. + +11.2 High Availability in a Multiple Switch Topology +---------------------------------------------------- + +With multiple switches, the configuration of bonding and the +network changes dramatically. In multiple switch topologies, there is +a trade off between network availability and usable bandwidth. + +Below is a sample network, configured to maximize the +availability of the network:: + + | | + |port3 port3| + +-----+----+ +-----+----+ + | |port2 ISL port2| | + | switch A +--------------------------+ switch B | + | | | | + +-----+----+ +-----++---+ + |port1 port1| + | +-------+ | + +-------------+ host1 +---------------+ + eth0 +-------+ eth1 + +In this configuration, there is a link between the two +switches (ISL, or inter switch link), and multiple ports connecting to +the outside world ("port3" on each switch). There is no technical +reason that this could not be extended to a third switch. + +11.2.1 HA Bonding Mode Selection for Multiple Switch Topology +------------------------------------------------------------- + +In a topology such as the example above, the active-backup and +broadcast modes are the only useful bonding modes when optimizing for +availability; the other modes require all links to terminate on the +same peer for them to behave rationally. + +active-backup: + This is generally the preferred mode, particularly if + the switches have an ISL and play together well. If the + network configuration is such that one switch is specifically + a backup switch (e.g., has lower capacity, higher cost, etc), + then the primary option can be used to insure that the + preferred link is always used when it is available. + +broadcast: + This mode is really a special purpose mode, and is suitable + only for very specific needs. For example, if the two + switches are not connected (no ISL), and the networks beyond + them are totally independent. In this case, if it is + necessary for some specific one-way traffic to reach both + independent networks, then the broadcast mode may be suitable. + +11.2.2 HA Link Monitoring Selection for Multiple Switch Topology +---------------------------------------------------------------- + +The choice of link monitoring ultimately depends upon your +switch. If the switch can reliably fail ports in response to other +failures, then either the MII or ARP monitors should work. For +example, in the above example, if the "port3" link fails at the remote +end, the MII monitor has no direct means to detect this. The ARP +monitor could be configured with a target at the remote end of port3, +thus detecting that failure without switch support. + +In general, however, in a multiple switch topology, the ARP +monitor can provide a higher level of reliability in detecting end to +end connectivity failures (which may be caused by the failure of any +individual component to pass traffic for any reason). Additionally, +the ARP monitor should be configured with multiple targets (at least +one for each switch in the network). This will insure that, +regardless of which switch is active, the ARP monitor has a suitable +target to query. + +Note, also, that of late many switches now support a functionality +generally referred to as "trunk failover." This is a feature of the +switch that causes the link state of a particular switch port to be set +down (or up) when the state of another switch port goes down (or up). +Its purpose is to propagate link failures from logically "exterior" ports +to the logically "interior" ports that bonding is able to monitor via +miimon. Availability and configuration for trunk failover varies by +switch, but this can be a viable alternative to the ARP monitor when using +suitable switches. + +12. Configuring Bonding for Maximum Throughput +============================================== + +12.1 Maximizing Throughput in a Single Switch Topology +------------------------------------------------------ + +In a single switch configuration, the best method to maximize +throughput depends upon the application and network environment. The +various load balancing modes each have strengths and weaknesses in +different environments, as detailed below. + +For this discussion, we will break down the topologies into +two categories. Depending upon the destination of most traffic, we +categorize them into either "gatewayed" or "local" configurations. + +In a gatewayed configuration, the "switch" is acting primarily +as a router, and the majority of traffic passes through this router to +other networks. An example would be the following:: + + + +----------+ +----------+ + | |eth0 port1| | to other networks + | Host A +---------------------+ router +-------------------> + | +---------------------+ | Hosts B and C are out + | |eth1 port2| | here somewhere + +----------+ +----------+ + +The router may be a dedicated router device, or another host +acting as a gateway. For our discussion, the important point is that +the majority of traffic from Host A will pass through the router to +some other network before reaching its final destination. + +In a gatewayed network configuration, although Host A may +communicate with many other systems, all of its traffic will be sent +and received via one other peer on the local network, the router. + +Note that the case of two systems connected directly via +multiple physical links is, for purposes of configuring bonding, the +same as a gatewayed configuration. In that case, it happens that all +traffic is destined for the "gateway" itself, not some other network +beyond the gateway. + +In a local configuration, the "switch" is acting primarily as +a switch, and the majority of traffic passes through this switch to +reach other stations on the same network. An example would be the +following:: + + +----------+ +----------+ +--------+ + | |eth0 port1| +-------+ Host B | + | Host A +------------+ switch |port3 +--------+ + | +------------+ | +--------+ + | |eth1 port2| +------------------+ Host C | + +----------+ +----------+port4 +--------+ + + +Again, the switch may be a dedicated switch device, or another +host acting as a gateway. For our discussion, the important point is +that the majority of traffic from Host A is destined for other hosts +on the same local network (Hosts B and C in the above example). + +In summary, in a gatewayed configuration, traffic to and from +the bonded device will be to the same MAC level peer on the network +(the gateway itself, i.e., the router), regardless of its final +destination. In a local configuration, traffic flows directly to and +from the final destinations, thus, each destination (Host B, Host C) +will be addressed directly by their individual MAC addresses. + +This distinction between a gatewayed and a local network +configuration is important because many of the load balancing modes +available use the MAC addresses of the local network source and +destination to make load balancing decisions. The behavior of each +mode is described below. + + +12.1.1 MT Bonding Mode Selection for Single Switch Topology +----------------------------------------------------------- + +This configuration is the easiest to set up and to understand, +although you will have to decide which bonding mode best suits your +needs. The trade offs for each mode are detailed below: + +balance-rr: + This mode is the only mode that will permit a single + TCP/IP connection to stripe traffic across multiple + interfaces. It is therefore the only mode that will allow a + single TCP/IP stream to utilize more than one interface's + worth of throughput. This comes at a cost, however: the + striping generally results in peer systems receiving packets out + of order, causing TCP/IP's congestion control system to kick + in, often by retransmitting segments. + + It is possible to adjust TCP/IP's congestion limits by + altering the net.ipv4.tcp_reordering sysctl parameter. The + usual default value is 3. But keep in mind TCP stack is able + to automatically increase this when it detects reorders. + + Note that the fraction of packets that will be delivered out of + order is highly variable, and is unlikely to be zero. The level + of reordering depends upon a variety of factors, including the + networking interfaces, the switch, and the topology of the + configuration. Speaking in general terms, higher speed network + cards produce more reordering (due to factors such as packet + coalescing), and a "many to many" topology will reorder at a + higher rate than a "many slow to one fast" configuration. + + Many switches do not support any modes that stripe traffic + (instead choosing a port based upon IP or MAC level addresses); + for those devices, traffic for a particular connection flowing + through the switch to a balance-rr bond will not utilize greater + than one interface's worth of bandwidth. + + If you are utilizing protocols other than TCP/IP, UDP for + example, and your application can tolerate out of order + delivery, then this mode can allow for single stream datagram + performance that scales near linearly as interfaces are added + to the bond. + + This mode requires the switch to have the appropriate ports + configured for "etherchannel" or "trunking." + +active-backup: + There is not much advantage in this network topology to + the active-backup mode, as the inactive backup devices are all + connected to the same peer as the primary. In this case, a + load balancing mode (with link monitoring) will provide the + same level of network availability, but with increased + available bandwidth. On the plus side, active-backup mode + does not require any configuration of the switch, so it may + have value if the hardware available does not support any of + the load balance modes. + +balance-xor: + This mode will limit traffic such that packets destined + for specific peers will always be sent over the same + interface. Since the destination is determined by the MAC + addresses involved, this mode works best in a "local" network + configuration (as described above), with destinations all on + the same local network. This mode is likely to be suboptimal + if all your traffic is passed through a single router (i.e., a + "gatewayed" network configuration, as described above). + + As with balance-rr, the switch ports need to be configured for + "etherchannel" or "trunking." + +broadcast: + Like active-backup, there is not much advantage to this + mode in this type of network topology. + +802.3ad: + This mode can be a good choice for this type of network + topology. The 802.3ad mode is an IEEE standard, so all peers + that implement 802.3ad should interoperate well. The 802.3ad + protocol includes automatic configuration of the aggregates, + so minimal manual configuration of the switch is needed + (typically only to designate that some set of devices is + available for 802.3ad). The 802.3ad standard also mandates + that frames be delivered in order (within certain limits), so + in general single connections will not see misordering of + packets. The 802.3ad mode does have some drawbacks: the + standard mandates that all devices in the aggregate operate at + the same speed and duplex. Also, as with all bonding load + balance modes other than balance-rr, no single connection will + be able to utilize more than a single interface's worth of + bandwidth. + + Additionally, the linux bonding 802.3ad implementation + distributes traffic by peer (using an XOR of MAC addresses + and packet type ID), so in a "gatewayed" configuration, all + outgoing traffic will generally use the same device. Incoming + traffic may also end up on a single device, but that is + dependent upon the balancing policy of the peer's 802.3ad + implementation. In a "local" configuration, traffic will be + distributed across the devices in the bond. + + Finally, the 802.3ad mode mandates the use of the MII monitor, + therefore, the ARP monitor is not available in this mode. + +balance-tlb: + The balance-tlb mode balances outgoing traffic by peer. + Since the balancing is done according to MAC address, in a + "gatewayed" configuration (as described above), this mode will + send all traffic across a single device. However, in a + "local" network configuration, this mode balances multiple + local network peers across devices in a vaguely intelligent + manner (not a simple XOR as in balance-xor or 802.3ad mode), + so that mathematically unlucky MAC addresses (i.e., ones that + XOR to the same value) will not all "bunch up" on a single + interface. + + Unlike 802.3ad, interfaces may be of differing speeds, and no + special switch configuration is required. On the down side, + in this mode all incoming traffic arrives over a single + interface, this mode requires certain ethtool support in the + network device driver of the slave interfaces, and the ARP + monitor is not available. + +balance-alb: + This mode is everything that balance-tlb is, and more. + It has all of the features (and restrictions) of balance-tlb, + and will also balance incoming traffic from local network + peers (as described in the Bonding Module Options section, + above). + + The only additional down side to this mode is that the network + device driver must support changing the hardware address while + the device is open. + +12.1.2 MT Link Monitoring for Single Switch Topology +---------------------------------------------------- + +The choice of link monitoring may largely depend upon which +mode you choose to use. The more advanced load balancing modes do not +support the use of the ARP monitor, and are thus restricted to using +the MII monitor (which does not provide as high a level of end to end +assurance as the ARP monitor). + +12.2 Maximum Throughput in a Multiple Switch Topology +----------------------------------------------------- + +Multiple switches may be utilized to optimize for throughput +when they are configured in parallel as part of an isolated network +between two or more systems, for example:: + + +-----------+ + | Host A | + +-+---+---+-+ + | | | + +--------+ | +---------+ + | | | + +------+---+ +-----+----+ +-----+----+ + | Switch A | | Switch B | | Switch C | + +------+---+ +-----+----+ +-----+----+ + | | | + +--------+ | +---------+ + | | | + +-+---+---+-+ + | Host B | + +-----------+ + +In this configuration, the switches are isolated from one +another. One reason to employ a topology such as this is for an +isolated network with many hosts (a cluster configured for high +performance, for example), using multiple smaller switches can be more +cost effective than a single larger switch, e.g., on a network with 24 +hosts, three 24 port switches can be significantly less expensive than +a single 72 port switch. + +If access beyond the network is required, an individual host +can be equipped with an additional network device connected to an +external network; this host then additionally acts as a gateway. + +12.2.1 MT Bonding Mode Selection for Multiple Switch Topology +------------------------------------------------------------- + +In actual practice, the bonding mode typically employed in +configurations of this type is balance-rr. Historically, in this +network configuration, the usual caveats about out of order packet +delivery are mitigated by the use of network adapters that do not do +any kind of packet coalescing (via the use of NAPI, or because the +device itself does not generate interrupts until some number of +packets has arrived). When employed in this fashion, the balance-rr +mode allows individual connections between two hosts to effectively +utilize greater than one interface's bandwidth. + +12.2.2 MT Link Monitoring for Multiple Switch Topology +------------------------------------------------------ + +Again, in actual practice, the MII monitor is most often used +in this configuration, as performance is given preference over +availability. The ARP monitor will function in this topology, but its +advantages over the MII monitor are mitigated by the volume of probes +needed as the number of systems involved grows (remember that each +host in the network is configured with bonding). + +13. Switch Behavior Issues +========================== + +13.1 Link Establishment and Failover Delays +------------------------------------------- + +Some switches exhibit undesirable behavior with regard to the +timing of link up and down reporting by the switch. + +First, when a link comes up, some switches may indicate that +the link is up (carrier available), but not pass traffic over the +interface for some period of time. This delay is typically due to +some type of autonegotiation or routing protocol, but may also occur +during switch initialization (e.g., during recovery after a switch +failure). If you find this to be a problem, specify an appropriate +value to the updelay bonding module option to delay the use of the +relevant interface(s). + +Second, some switches may "bounce" the link state one or more +times while a link is changing state. This occurs most commonly while +the switch is initializing. Again, an appropriate updelay value may +help. + +Note that when a bonding interface has no active links, the +driver will immediately reuse the first link that goes up, even if the +updelay parameter has been specified (the updelay is ignored in this +case). If there are slave interfaces waiting for the updelay timeout +to expire, the interface that first went into that state will be +immediately reused. This reduces down time of the network if the +value of updelay has been overestimated, and since this occurs only in +cases with no connectivity, there is no additional penalty for +ignoring the updelay. + +In addition to the concerns about switch timings, if your +switches take a long time to go into backup mode, it may be desirable +to not activate a backup interface immediately after a link goes down. +Failover may be delayed via the downdelay bonding module option. + +13.2 Duplicated Incoming Packets +-------------------------------- + +NOTE: Starting with version 3.0.2, the bonding driver has logic to +suppress duplicate packets, which should largely eliminate this problem. +The following description is kept for reference. + +It is not uncommon to observe a short burst of duplicated +traffic when the bonding device is first used, or after it has been +idle for some period of time. This is most easily observed by issuing +a "ping" to some other host on the network, and noticing that the +output from ping flags duplicates (typically one per slave). + +For example, on a bond in active-backup mode with five slaves +all connected to one switch, the output may appear as follows:: + + # ping -n 10.0.4.2 + PING 10.0.4.2 (10.0.4.2) from 10.0.3.10 : 56(84) bytes of data. + 64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.7 ms + 64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.8 ms (DUP!) + 64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.8 ms (DUP!) + 64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.8 ms (DUP!) + 64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.8 ms (DUP!) + 64 bytes from 10.0.4.2: icmp_seq=2 ttl=64 time=0.216 ms + 64 bytes from 10.0.4.2: icmp_seq=3 ttl=64 time=0.267 ms + 64 bytes from 10.0.4.2: icmp_seq=4 ttl=64 time=0.222 ms + +This is not due to an error in the bonding driver, rather, it +is a side effect of how many switches update their MAC forwarding +tables. Initially, the switch does not associate the MAC address in +the packet with a particular switch port, and so it may send the +traffic to all ports until its MAC forwarding table is updated. Since +the interfaces attached to the bond may occupy multiple ports on a +single switch, when the switch (temporarily) floods the traffic to all +ports, the bond device receives multiple copies of the same packet +(one per slave device). + +The duplicated packet behavior is switch dependent, some +switches exhibit this, and some do not. On switches that display this +behavior, it can be induced by clearing the MAC forwarding table (on +most Cisco switches, the privileged command "clear mac address-table +dynamic" will accomplish this). + +14. Hardware Specific Considerations +==================================== + +This section contains additional information for configuring +bonding on specific hardware platforms, or for interfacing bonding +with particular switches or other devices. + +14.1 IBM BladeCenter +-------------------- + +This applies to the JS20 and similar systems. + +On the JS20 blades, the bonding driver supports only +balance-rr, active-backup, balance-tlb and balance-alb modes. This is +largely due to the network topology inside the BladeCenter, detailed +below. + +JS20 network adapter information +-------------------------------- + +All JS20s come with two Broadcom Gigabit Ethernet ports +integrated on the planar (that's "motherboard" in IBM-speak). In the +BladeCenter chassis, the eth0 port of all JS20 blades is hard wired to +I/O Module #1; similarly, all eth1 ports are wired to I/O Module #2. +An add-on Broadcom daughter card can be installed on a JS20 to provide +two more Gigabit Ethernet ports. These ports, eth2 and eth3, are +wired to I/O Modules 3 and 4, respectively. + +Each I/O Module may contain either a switch or a passthrough +module (which allows ports to be directly connected to an external +switch). Some bonding modes require a specific BladeCenter internal +network topology in order to function; these are detailed below. + +Additional BladeCenter-specific networking information can be +found in two IBM Redbooks (www.ibm.com/redbooks): + +- "IBM eServer BladeCenter Networking Options" +- "IBM eServer BladeCenter Layer 2-7 Network Switching" + +BladeCenter networking configuration +------------------------------------ + +Because a BladeCenter can be configured in a very large number +of ways, this discussion will be confined to describing basic +configurations. + +Normally, Ethernet Switch Modules (ESMs) are used in I/O +modules 1 and 2. In this configuration, the eth0 and eth1 ports of a +JS20 will be connected to different internal switches (in the +respective I/O modules). + +A passthrough module (OPM or CPM, optical or copper, +passthrough module) connects the I/O module directly to an external +switch. By using PMs in I/O module #1 and #2, the eth0 and eth1 +interfaces of a JS20 can be redirected to the outside world and +connected to a common external switch. + +Depending upon the mix of ESMs and PMs, the network will +appear to bonding as either a single switch topology (all PMs) or as a +multiple switch topology (one or more ESMs, zero or more PMs). It is +also possible to connect ESMs together, resulting in a configuration +much like the example in "High Availability in a Multiple Switch +Topology," above. + +Requirements for specific modes +------------------------------- + +The balance-rr mode requires the use of passthrough modules +for devices in the bond, all connected to an common external switch. +That switch must be configured for "etherchannel" or "trunking" on the +appropriate ports, as is usual for balance-rr. + +The balance-alb and balance-tlb modes will function with +either switch modules or passthrough modules (or a mix). The only +specific requirement for these modes is that all network interfaces +must be able to reach all destinations for traffic sent over the +bonding device (i.e., the network must converge at some point outside +the BladeCenter). + +The active-backup mode has no additional requirements. + +Link monitoring issues +---------------------- + +When an Ethernet Switch Module is in place, only the ARP +monitor will reliably detect link loss to an external switch. This is +nothing unusual, but examination of the BladeCenter cabinet would +suggest that the "external" network ports are the ethernet ports for +the system, when it fact there is a switch between these "external" +ports and the devices on the JS20 system itself. The MII monitor is +only able to detect link failures between the ESM and the JS20 system. + +When a passthrough module is in place, the MII monitor does +detect failures to the "external" port, which is then directly +connected to the JS20 system. + +Other concerns +-------------- + +The Serial Over LAN (SoL) link is established over the primary +ethernet (eth0) only, therefore, any loss of link to eth0 will result +in losing your SoL connection. It will not fail over with other +network traffic, as the SoL system is beyond the control of the +bonding driver. + +It may be desirable to disable spanning tree on the switch +(either the internal Ethernet Switch Module, or an external switch) to +avoid fail-over delay issues when using bonding. + + +15. Frequently Asked Questions +============================== + +1. Is it SMP safe? +------------------- + +Yes. The old 2.0.xx channel bonding patch was not SMP safe. +The new driver was designed to be SMP safe from the start. + +2. What type of cards will work with it? +----------------------------------------- + +Any Ethernet type cards (you can even mix cards - a Intel +EtherExpress PRO/100 and a 3com 3c905b, for example). For most modes, +devices need not be of the same speed. + +Starting with version 3.2.1, bonding also supports Infiniband +slaves in active-backup mode. + +3. How many bonding devices can I have? +---------------------------------------- + +There is no limit. + +4. How many slaves can a bonding device have? +---------------------------------------------- + +This is limited only by the number of network interfaces Linux +supports and/or the number of network cards you can place in your +system. + +5. What happens when a slave link dies? +---------------------------------------- + +If link monitoring is enabled, then the failing device will be +disabled. The active-backup mode will fail over to a backup link, and +other modes will ignore the failed link. The link will continue to be +monitored, and should it recover, it will rejoin the bond (in whatever +manner is appropriate for the mode). See the sections on High +Availability and the documentation for each mode for additional +information. + +Link monitoring can be enabled via either the miimon or +arp_interval parameters (described in the module parameters section, +above). In general, miimon monitors the carrier state as sensed by +the underlying network device, and the arp monitor (arp_interval) +monitors connectivity to another host on the local network. + +If no link monitoring is configured, the bonding driver will +be unable to detect link failures, and will assume that all links are +always available. This will likely result in lost packets, and a +resulting degradation of performance. The precise performance loss +depends upon the bonding mode and network configuration. + +6. Can bonding be used for High Availability? +---------------------------------------------- + +Yes. See the section on High Availability for details. + +7. Which switches/systems does it work with? +--------------------------------------------- + +The full answer to this depends upon the desired mode. + +In the basic balance modes (balance-rr and balance-xor), it +works with any system that supports etherchannel (also called +trunking). Most managed switches currently available have such +support, and many unmanaged switches as well. + +The advanced balance modes (balance-tlb and balance-alb) do +not have special switch requirements, but do need device drivers that +support specific features (described in the appropriate section under +module parameters, above). + +In 802.3ad mode, it works with systems that support IEEE +802.3ad Dynamic Link Aggregation. Most managed and many unmanaged +switches currently available support 802.3ad. + +The active-backup mode should work with any Layer-II switch. + +8. Where does a bonding device get its MAC address from? +--------------------------------------------------------- + +When using slave devices that have fixed MAC addresses, or when +the fail_over_mac option is enabled, the bonding device's MAC address is +the MAC address of the active slave. + +For other configurations, if not explicitly configured (with +ifconfig or ip link), the MAC address of the bonding device is taken from +its first slave device. This MAC address is then passed to all following +slaves and remains persistent (even if the first slave is removed) until +the bonding device is brought down or reconfigured. + +If you wish to change the MAC address, you can set it with +ifconfig or ip link:: + + # ifconfig bond0 hw ether 00:11:22:33:44:55 + + # ip link set bond0 address 66:77:88:99:aa:bb + +The MAC address can be also changed by bringing down/up the +device and then changing its slaves (or their order):: + + # ifconfig bond0 down ; modprobe -r bonding + # ifconfig bond0 .... up + # ifenslave bond0 eth... + +This method will automatically take the address from the next +slave that is added. + +To restore your slaves' MAC addresses, you need to detach them +from the bond (``ifenslave -d bond0 eth0``). The bonding driver will +then restore the MAC addresses that the slaves had before they were +enslaved. + +16. Resources and Links +======================= + +The latest version of the bonding driver can be found in the latest +version of the linux kernel, found on http://kernel.org + +The latest version of this document can be found in the latest kernel +source (named Documentation/networking/bonding.rst). + +Discussions regarding the development of the bonding driver take place +on the main Linux network mailing list, hosted at vger.kernel.org. The list +address is: + +netdev@vger.kernel.org + +The administrative interface (to subscribe or unsubscribe) can +be found at: + +http://vger.kernel.org/vger-lists.html#netdev diff --git a/Documentation/networking/bridge.rst b/Documentation/networking/bridge.rst new file mode 100644 index 0000000000..c859f3c163 --- /dev/null +++ b/Documentation/networking/bridge.rst @@ -0,0 +1,21 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================= +Ethernet Bridging +================= + +In order to use the Ethernet bridging functionality, you'll need the +userspace tools. + +Documentation for Linux bridging is on: + https://wiki.linuxfoundation.org/networking/bridge + +The bridge-utilities are maintained at: + git://git.kernel.org/pub/scm/linux/kernel/git/shemminger/bridge-utils.git + +Additionally, the iproute2 utilities can be used to configure +bridge devices. + +If you still have questions, don't hesitate to post to the mailing list +(more info https://lists.linux-foundation.org/mailman/listinfo/bridge). + diff --git a/Documentation/networking/caif/caif.rst b/Documentation/networking/caif/caif.rst new file mode 100644 index 0000000000..d922d419c5 --- /dev/null +++ b/Documentation/networking/caif/caif.rst @@ -0,0 +1,138 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> + + +================ +Using Linux CAIF +================ + + +:Copyright: |copy| ST-Ericsson AB 2010 + +:Author: Sjur Brendeland/ sjur.brandeland@stericsson.com + +Start +===== + +If you have compiled CAIF for modules do:: + + $modprobe crc_ccitt + $modprobe caif + $modprobe caif_socket + $modprobe chnl_net + + +Preparing the setup with a STE modem +==================================== + +If you are working on integration of CAIF you should make sure +that the kernel is built with module support. + +There are some things that need to be tweaked to get the host TTY correctly +set up to talk to the modem. +Since the CAIF stack is running in the kernel and we want to use the existing +TTY, we are installing our physical serial driver as a line discipline above +the TTY device. + +To achieve this we need to install the N_CAIF ldisc from user space. +The benefit is that we can hook up to any TTY. + +The use of Start-of-frame-extension (STX) must also be set as +module parameter "ser_use_stx". + +Normally Frame Checksum is always used on UART, but this is also provided as a +module parameter "ser_use_fcs". + +:: + + $ modprobe caif_serial ser_ttyname=/dev/ttyS0 ser_use_stx=yes + $ ifconfig caif_ttyS0 up + +PLEASE NOTE: + There is a limitation in Android shell. + It only accepts one argument to insmod/modprobe! + +Trouble shooting +================ + +There are debugfs parameters provided for serial communication. +/sys/kernel/debug/caif_serial/<tty-name>/ + +* ser_state: Prints the bit-mask status where + + - 0x02 means SENDING, this is a transient state. + - 0x10 means FLOW_OFF_SENT, i.e. the previous frame has not been sent + and is blocking further send operation. Flow OFF has been propagated + to all CAIF Channels using this TTY. + +* tty_status: Prints the bit-mask tty status information + + - 0x01 - tty->warned is on. + - 0x04 - tty->packed is on. + - 0x08 - tty->flow.tco_stopped is on. + - 0x10 - tty->hw_stopped is on. + - 0x20 - tty->flow.stopped is on. + +* last_tx_msg: Binary blob Prints the last transmitted frame. + + This can be printed with:: + + $od --format=x1 /sys/kernel/debug/caif_serial/<tty>/last_rx_msg. + + The first two tx messages sent look like this. Note: The initial + byte 02 is start of frame extension (STX) used for re-syncing + upon errors. + + - Enumeration:: + + 0000000 02 05 00 00 03 01 d2 02 + | | | | | | + STX(1) | | | | + Length(2)| | | + Control Channel(1) + Command:Enumeration(1) + Link-ID(1) + Checksum(2) + + - Channel Setup:: + + 0000000 02 07 00 00 00 21 a1 00 48 df + | | | | | | | | + STX(1) | | | | | | + Length(2)| | | | | + Control Channel(1) + Command:Channel Setup(1) + Channel Type(1) + Priority and Link-ID(1) + Endpoint(1) + Checksum(2) + +* last_rx_msg: Prints the last transmitted frame. + + The RX messages for LinkSetup look almost identical but they have the + bit 0x20 set in the command bit, and Channel Setup has added one byte + before Checksum containing Channel ID. + + NOTE: + Several CAIF Messages might be concatenated. The maximum debug + buffer size is 128 bytes. + +Error Scenarios +=============== + +- last_tx_msg contains channel setup message and last_rx_msg is empty -> + The host seems to be able to send over the UART, at least the CAIF ldisc get + notified that sending is completed. + +- last_tx_msg contains enumeration message and last_rx_msg is empty -> + The host is not able to send the message from UART, the tty has not been + able to complete the transmit operation. + +- if /sys/kernel/debug/caif_serial/<tty>/tty_status is non-zero there + might be problems transmitting over UART. + + E.g. host and modem wiring is not correct you will typically see + tty_status = 0x10 (hw_stopped) and ser_state = 0x10 (FLOW_OFF_SENT). + + You will probably see the enumeration message in last_tx_message + and empty last_rx_message. diff --git a/Documentation/networking/caif/index.rst b/Documentation/networking/caif/index.rst new file mode 100644 index 0000000000..ec29b6f4bd --- /dev/null +++ b/Documentation/networking/caif/index.rst @@ -0,0 +1,12 @@ +.. SPDX-License-Identifier: GPL-2.0 + +CAIF +==== + +Contents: + +.. toctree:: + :maxdepth: 2 + + linux_caif + caif diff --git a/Documentation/networking/caif/linux_caif.rst b/Documentation/networking/caif/linux_caif.rst new file mode 100644 index 0000000000..a0480862ab --- /dev/null +++ b/Documentation/networking/caif/linux_caif.rst @@ -0,0 +1,195 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> + +========== +Linux CAIF +========== + +Copyright |copy| ST-Ericsson AB 2010 + +:Author: Sjur Brendeland/ sjur.brandeland@stericsson.com +:License terms: GNU General Public License (GPL) version 2 + + +Introduction +============ + +CAIF is a MUX protocol used by ST-Ericsson cellular modems for +communication between Modem and host. The host processes can open virtual AT +channels, initiate GPRS Data connections, Video channels and Utility Channels. +The Utility Channels are general purpose pipes between modem and host. + +ST-Ericsson modems support a number of transports between modem +and host. Currently, UART and Loopback are available for Linux. + + +Architecture +============ + +The implementation of CAIF is divided into: + +* CAIF Socket Layer and GPRS IP Interface. +* CAIF Core Protocol Implementation +* CAIF Link Layer, implemented as NET devices. + +:: + + RTNL + ! + ! +------+ +------+ + ! +------+! +------+! + ! ! IP !! !Socket!! + +-------> !interf!+ ! API !+ <- CAIF Client APIs + ! +------+ +------! + ! ! ! + ! +-----------+ + ! ! + ! +------+ <- CAIF Core Protocol + ! ! CAIF ! + ! ! Core ! + ! +------+ + ! +----------!---------+ + ! ! ! ! + ! +------+ +-----+ +------+ + +--> ! HSI ! ! TTY ! ! USB ! <- Link Layer (Net Devices) + +------+ +-----+ +------+ + + + +Implementation +============== + + +CAIF Core Protocol Layer +------------------------ + +CAIF Core layer implements the CAIF protocol as defined by ST-Ericsson. +It implements the CAIF protocol stack in a layered approach, where +each layer described in the specification is implemented as a separate layer. +The architecture is inspired by the design patterns "Protocol Layer" and +"Protocol Packet". + +CAIF structure +^^^^^^^^^^^^^^ + +The Core CAIF implementation contains: + + - Simple implementation of CAIF. + - Layered architecture (a la Streams), each layer in the CAIF + specification is implemented in a separate c-file. + - Clients must call configuration function to add PHY layer. + - Clients must implement CAIF layer to consume/produce + CAIF payload with receive and transmit functions. + - Clients must call configuration function to add and connect the + Client layer. + - When receiving / transmitting CAIF Packets (cfpkt), ownership is passed + to the called function (except for framing layers' receive function) + +Layered Architecture +==================== + +The CAIF protocol can be divided into two parts: Support functions and Protocol +Implementation. The support functions include: + + - CFPKT CAIF Packet. Implementation of CAIF Protocol Packet. The + CAIF Packet has functions for creating, destroying and adding content + and for adding/extracting header and trailers to protocol packets. + +The CAIF Protocol implementation contains: + + - CFCNFG CAIF Configuration layer. Configures the CAIF Protocol + Stack and provides a Client interface for adding Link-Layer and + Driver interfaces on top of the CAIF Stack. + + - CFCTRL CAIF Control layer. Encodes and Decodes control messages + such as enumeration and channel setup. Also matches request and + response messages. + + - CFSERVL General CAIF Service Layer functionality; handles flow + control and remote shutdown requests. + + - CFVEI CAIF VEI layer. Handles CAIF AT Channels on VEI (Virtual + External Interface). This layer encodes/decodes VEI frames. + + - CFDGML CAIF Datagram layer. Handles CAIF Datagram layer (IP + traffic), encodes/decodes Datagram frames. + + - CFMUX CAIF Mux layer. Handles multiplexing between multiple + physical bearers and multiple channels such as VEI, Datagram, etc. + The MUX keeps track of the existing CAIF Channels and + Physical Instances and selects the appropriate instance based + on Channel-Id and Physical-ID. + + - CFFRML CAIF Framing layer. Handles Framing i.e. Frame length + and frame checksum. + + - CFSERL CAIF Serial layer. Handles concatenation/split of frames + into CAIF Frames with correct length. + +:: + + +---------+ + | Config | + | CFCNFG | + +---------+ + ! + +---------+ +---------+ +---------+ + | AT | | Control | | Datagram| + | CFVEIL | | CFCTRL | | CFDGML | + +---------+ +---------+ +---------+ + \_____________!______________/ + ! + +---------+ + | MUX | + | | + +---------+ + _____!_____ + / \ + +---------+ +---------+ + | CFFRML | | CFFRML | + | Framing | | Framing | + +---------+ +---------+ + ! ! + +---------+ +---------+ + | | | Serial | + | | | CFSERL | + +---------+ +---------+ + + +In this layered approach the following "rules" apply. + + - All layers embed the same structure "struct cflayer" + - A layer does not depend on any other layer's private data. + - Layers are stacked by setting the pointers:: + + layer->up , layer->dn + + - In order to send data upwards, each layer should do:: + + layer->up->receive(layer->up, packet); + + - In order to send data downwards, each layer should do:: + + layer->dn->transmit(layer->dn, packet); + + +CAIF Socket and IP interface +============================ + +The IP interface and CAIF socket API are implemented on top of the +CAIF Core protocol. The IP Interface and CAIF socket have an instance of +'struct cflayer', just like the CAIF Core protocol stack. +Net device and Socket implement the 'receive()' function defined by +'struct cflayer', just like the rest of the CAIF stack. In this way, transmit and +receive of packets is handled as by the rest of the layers: the 'dn->transmit()' +function is called in order to transmit data. + +Configuration of Link Layer +--------------------------- +The Link Layer is implemented as Linux network devices (struct net_device). +Payload handling and registration is done using standard Linux mechanisms. + +The CAIF Protocol relies on a loss-less link layer without implementing +retransmission. This implies that packet drops must not happen. +Therefore a flow-control mechanism is implemented where the physical +interface can initiate flow stop for all CAIF Channels. diff --git a/Documentation/networking/can.rst b/Documentation/networking/can.rst new file mode 100644 index 0000000000..d7e1ada905 --- /dev/null +++ b/Documentation/networking/can.rst @@ -0,0 +1,1508 @@ +=================================== +SocketCAN - Controller Area Network +=================================== + +Overview / What is SocketCAN +============================ + +The socketcan package is an implementation of CAN protocols +(Controller Area Network) for Linux. CAN is a networking technology +which has widespread use in automation, embedded devices, and +automotive fields. While there have been other CAN implementations +for Linux based on character devices, SocketCAN uses the Berkeley +socket API, the Linux network stack and implements the CAN device +drivers as network interfaces. The CAN socket API has been designed +as similar as possible to the TCP/IP protocols to allow programmers, +familiar with network programming, to easily learn how to use CAN +sockets. + + +.. _socketcan-motivation: + +Motivation / Why Using the Socket API +===================================== + +There have been CAN implementations for Linux before SocketCAN so the +question arises, why we have started another project. Most existing +implementations come as a device driver for some CAN hardware, they +are based on character devices and provide comparatively little +functionality. Usually, there is only a hardware-specific device +driver which provides a character device interface to send and +receive raw CAN frames, directly to/from the controller hardware. +Queueing of frames and higher-level transport protocols like ISO-TP +have to be implemented in user space applications. Also, most +character-device implementations support only one single process to +open the device at a time, similar to a serial interface. Exchanging +the CAN controller requires employment of another device driver and +often the need for adaption of large parts of the application to the +new driver's API. + +SocketCAN was designed to overcome all of these limitations. A new +protocol family has been implemented which provides a socket interface +to user space applications and which builds upon the Linux network +layer, enabling use all of the provided queueing functionality. A device +driver for CAN controller hardware registers itself with the Linux +network layer as a network device, so that CAN frames from the +controller can be passed up to the network layer and on to the CAN +protocol family module and also vice-versa. Also, the protocol family +module provides an API for transport protocol modules to register, so +that any number of transport protocols can be loaded or unloaded +dynamically. In fact, the can core module alone does not provide any +protocol and cannot be used without loading at least one additional +protocol module. Multiple sockets can be opened at the same time, +on different or the same protocol module and they can listen/send +frames on different or the same CAN IDs. Several sockets listening on +the same interface for frames with the same CAN ID are all passed the +same received matching CAN frames. An application wishing to +communicate using a specific transport protocol, e.g. ISO-TP, just +selects that protocol when opening the socket, and then can read and +write application data byte streams, without having to deal with +CAN-IDs, frames, etc. + +Similar functionality visible from user-space could be provided by a +character device, too, but this would lead to a technically inelegant +solution for a couple of reasons: + +* **Intricate usage:** Instead of passing a protocol argument to + socket(2) and using bind(2) to select a CAN interface and CAN ID, an + application would have to do all these operations using ioctl(2)s. + +* **Code duplication:** A character device cannot make use of the Linux + network queueing code, so all that code would have to be duplicated + for CAN networking. + +* **Abstraction:** In most existing character-device implementations, the + hardware-specific device driver for a CAN controller directly + provides the character device for the application to work with. + This is at least very unusual in Unix systems for both, char and + block devices. For example you don't have a character device for a + certain UART of a serial interface, a certain sound chip in your + computer, a SCSI or IDE controller providing access to your hard + disk or tape streamer device. Instead, you have abstraction layers + which provide a unified character or block device interface to the + application on the one hand, and a interface for hardware-specific + device drivers on the other hand. These abstractions are provided + by subsystems like the tty layer, the audio subsystem or the SCSI + and IDE subsystems for the devices mentioned above. + + The easiest way to implement a CAN device driver is as a character + device without such a (complete) abstraction layer, as is done by most + existing drivers. The right way, however, would be to add such a + layer with all the functionality like registering for certain CAN + IDs, supporting several open file descriptors and (de)multiplexing + CAN frames between them, (sophisticated) queueing of CAN frames, and + providing an API for device drivers to register with. However, then + it would be no more difficult, or may be even easier, to use the + networking framework provided by the Linux kernel, and this is what + SocketCAN does. + +The use of the networking framework of the Linux kernel is just the +natural and most appropriate way to implement CAN for Linux. + + +.. _socketcan-concept: + +SocketCAN Concept +================= + +As described in :ref:`socketcan-motivation` the main goal of SocketCAN is to +provide a socket interface to user space applications which builds +upon the Linux network layer. In contrast to the commonly known +TCP/IP and ethernet networking, the CAN bus is a broadcast-only(!) +medium that has no MAC-layer addressing like ethernet. The CAN-identifier +(can_id) is used for arbitration on the CAN-bus. Therefore the CAN-IDs +have to be chosen uniquely on the bus. When designing a CAN-ECU +network the CAN-IDs are mapped to be sent by a specific ECU. +For this reason a CAN-ID can be treated best as a kind of source address. + + +.. _socketcan-receive-lists: + +Receive Lists +------------- + +The network transparent access of multiple applications leads to the +problem that different applications may be interested in the same +CAN-IDs from the same CAN network interface. The SocketCAN core +module - which implements the protocol family CAN - provides several +high efficient receive lists for this reason. If e.g. a user space +application opens a CAN RAW socket, the raw protocol module itself +requests the (range of) CAN-IDs from the SocketCAN core that are +requested by the user. The subscription and unsubscription of +CAN-IDs can be done for specific CAN interfaces or for all(!) known +CAN interfaces with the can_rx_(un)register() functions provided to +CAN protocol modules by the SocketCAN core (see :ref:`socketcan-core-module`). +To optimize the CPU usage at runtime the receive lists are split up +into several specific lists per device that match the requested +filter complexity for a given use-case. + + +.. _socketcan-local-loopback1: + +Local Loopback of Sent Frames +----------------------------- + +As known from other networking concepts the data exchanging +applications may run on the same or different nodes without any +change (except for the according addressing information): + +.. code:: + + ___ ___ ___ _______ ___ + | _ | | _ | | _ | | _ _ | | _ | + ||A|| ||B|| ||C|| ||A| |B|| ||C|| + |___| |___| |___| |_______| |___| + | | | | | + -----------------(1)- CAN bus -(2)--------------- + +To ensure that application A receives the same information in the +example (2) as it would receive in example (1) there is need for +some kind of local loopback of the sent CAN frames on the appropriate +node. + +The Linux network devices (by default) just can handle the +transmission and reception of media dependent frames. Due to the +arbitration on the CAN bus the transmission of a low prio CAN-ID +may be delayed by the reception of a high prio CAN frame. To +reflect the correct [#f1]_ traffic on the node the loopback of the sent +data has to be performed right after a successful transmission. If +the CAN network interface is not capable of performing the loopback for +some reason the SocketCAN core can do this task as a fallback solution. +See :ref:`socketcan-local-loopback2` for details (recommended). + +The loopback functionality is enabled by default to reflect standard +networking behaviour for CAN applications. Due to some requests from +the RT-SocketCAN group the loopback optionally may be disabled for each +separate socket. See sockopts from the CAN RAW sockets in :ref:`socketcan-raw-sockets`. + +.. [#f1] you really like to have this when you're running analyser + tools like 'candump' or 'cansniffer' on the (same) node. + + +.. _socketcan-network-problem-notifications: + +Network Problem Notifications +----------------------------- + +The use of the CAN bus may lead to several problems on the physical +and media access control layer. Detecting and logging of these lower +layer problems is a vital requirement for CAN users to identify +hardware issues on the physical transceiver layer as well as +arbitration problems and error frames caused by the different +ECUs. The occurrence of detected errors are important for diagnosis +and have to be logged together with the exact timestamp. For this +reason the CAN interface driver can generate so called Error Message +Frames that can optionally be passed to the user application in the +same way as other CAN frames. Whenever an error on the physical layer +or the MAC layer is detected (e.g. by the CAN controller) the driver +creates an appropriate error message frame. Error messages frames can +be requested by the user application using the common CAN filter +mechanisms. Inside this filter definition the (interested) type of +errors may be selected. The reception of error messages is disabled +by default. The format of the CAN error message frame is briefly +described in the Linux header file "include/uapi/linux/can/error.h". + + +How to use SocketCAN +==================== + +Like TCP/IP, you first need to open a socket for communicating over a +CAN network. Since SocketCAN implements a new protocol family, you +need to pass PF_CAN as the first argument to the socket(2) system +call. Currently, there are two CAN protocols to choose from, the raw +socket protocol and the broadcast manager (BCM). So to open a socket, +you would write:: + + s = socket(PF_CAN, SOCK_RAW, CAN_RAW); + +and:: + + s = socket(PF_CAN, SOCK_DGRAM, CAN_BCM); + +respectively. After the successful creation of the socket, you would +normally use the bind(2) system call to bind the socket to a CAN +interface (which is different from TCP/IP due to different addressing +- see :ref:`socketcan-concept`). After binding (CAN_RAW) or connecting (CAN_BCM) +the socket, you can read(2) and write(2) from/to the socket or use +send(2), sendto(2), sendmsg(2) and the recv* counterpart operations +on the socket as usual. There are also CAN specific socket options +described below. + +The Classical CAN frame structure (aka CAN 2.0B), the CAN FD frame structure +and the sockaddr structure are defined in include/linux/can.h: + +.. code-block:: C + + struct can_frame { + canid_t can_id; /* 32 bit CAN_ID + EFF/RTR/ERR flags */ + union { + /* CAN frame payload length in byte (0 .. CAN_MAX_DLEN) + * was previously named can_dlc so we need to carry that + * name for legacy support + */ + __u8 len; + __u8 can_dlc; /* deprecated */ + }; + __u8 __pad; /* padding */ + __u8 __res0; /* reserved / padding */ + __u8 len8_dlc; /* optional DLC for 8 byte payload length (9 .. 15) */ + __u8 data[8] __attribute__((aligned(8))); + }; + +Remark: The len element contains the payload length in bytes and should be +used instead of can_dlc. The deprecated can_dlc was misleadingly named as +it always contained the plain payload length in bytes and not the so called +'data length code' (DLC). + +To pass the raw DLC from/to a Classical CAN network device the len8_dlc +element can contain values 9 .. 15 when the len element is 8 (the real +payload length for all DLC values greater or equal to 8). + +The alignment of the (linear) payload data[] to a 64bit boundary +allows the user to define their own structs and unions to easily access +the CAN payload. There is no given byteorder on the CAN bus by +default. A read(2) system call on a CAN_RAW socket transfers a +struct can_frame to the user space. + +The sockaddr_can structure has an interface index like the +PF_PACKET socket, that also binds to a specific interface: + +.. code-block:: C + + struct sockaddr_can { + sa_family_t can_family; + int can_ifindex; + union { + /* transport protocol class address info (e.g. ISOTP) */ + struct { canid_t rx_id, tx_id; } tp; + + /* J1939 address information */ + struct { + /* 8 byte name when using dynamic addressing */ + __u64 name; + + /* pgn: + * 8 bit: PS in PDU2 case, else 0 + * 8 bit: PF + * 1 bit: DP + * 1 bit: reserved + */ + __u32 pgn; + + /* 1 byte address */ + __u8 addr; + } j1939; + + /* reserved for future CAN protocols address information */ + } can_addr; + }; + +To determine the interface index an appropriate ioctl() has to +be used (example for CAN_RAW sockets without error checking): + +.. code-block:: C + + int s; + struct sockaddr_can addr; + struct ifreq ifr; + + s = socket(PF_CAN, SOCK_RAW, CAN_RAW); + + strcpy(ifr.ifr_name, "can0" ); + ioctl(s, SIOCGIFINDEX, &ifr); + + addr.can_family = AF_CAN; + addr.can_ifindex = ifr.ifr_ifindex; + + bind(s, (struct sockaddr *)&addr, sizeof(addr)); + + (..) + +To bind a socket to all(!) CAN interfaces the interface index must +be 0 (zero). In this case the socket receives CAN frames from every +enabled CAN interface. To determine the originating CAN interface +the system call recvfrom(2) may be used instead of read(2). To send +on a socket that is bound to 'any' interface sendto(2) is needed to +specify the outgoing interface. + +Reading CAN frames from a bound CAN_RAW socket (see above) consists +of reading a struct can_frame: + +.. code-block:: C + + struct can_frame frame; + + nbytes = read(s, &frame, sizeof(struct can_frame)); + + if (nbytes < 0) { + perror("can raw socket read"); + return 1; + } + + /* paranoid check ... */ + if (nbytes < sizeof(struct can_frame)) { + fprintf(stderr, "read: incomplete CAN frame\n"); + return 1; + } + + /* do something with the received CAN frame */ + +Writing CAN frames can be done similarly, with the write(2) system call:: + + nbytes = write(s, &frame, sizeof(struct can_frame)); + +When the CAN interface is bound to 'any' existing CAN interface +(addr.can_ifindex = 0) it is recommended to use recvfrom(2) if the +information about the originating CAN interface is needed: + +.. code-block:: C + + struct sockaddr_can addr; + struct ifreq ifr; + socklen_t len = sizeof(addr); + struct can_frame frame; + + nbytes = recvfrom(s, &frame, sizeof(struct can_frame), + 0, (struct sockaddr*)&addr, &len); + + /* get interface name of the received CAN frame */ + ifr.ifr_ifindex = addr.can_ifindex; + ioctl(s, SIOCGIFNAME, &ifr); + printf("Received a CAN frame from interface %s", ifr.ifr_name); + +To write CAN frames on sockets bound to 'any' CAN interface the +outgoing interface has to be defined certainly: + +.. code-block:: C + + strcpy(ifr.ifr_name, "can0"); + ioctl(s, SIOCGIFINDEX, &ifr); + addr.can_ifindex = ifr.ifr_ifindex; + addr.can_family = AF_CAN; + + nbytes = sendto(s, &frame, sizeof(struct can_frame), + 0, (struct sockaddr*)&addr, sizeof(addr)); + +An accurate timestamp can be obtained with an ioctl(2) call after reading +a message from the socket: + +.. code-block:: C + + struct timeval tv; + ioctl(s, SIOCGSTAMP, &tv); + +The timestamp has a resolution of one microsecond and is set automatically +at the reception of a CAN frame. + +Remark about CAN FD (flexible data rate) support: + +Generally the handling of CAN FD is very similar to the formerly described +examples. The new CAN FD capable CAN controllers support two different +bitrates for the arbitration phase and the payload phase of the CAN FD frame +and up to 64 bytes of payload. This extended payload length breaks all the +kernel interfaces (ABI) which heavily rely on the CAN frame with fixed eight +bytes of payload (struct can_frame) like the CAN_RAW socket. Therefore e.g. +the CAN_RAW socket supports a new socket option CAN_RAW_FD_FRAMES that +switches the socket into a mode that allows the handling of CAN FD frames +and Classical CAN frames simultaneously (see :ref:`socketcan-rawfd`). + +The struct canfd_frame is defined in include/linux/can.h: + +.. code-block:: C + + struct canfd_frame { + canid_t can_id; /* 32 bit CAN_ID + EFF/RTR/ERR flags */ + __u8 len; /* frame payload length in byte (0 .. 64) */ + __u8 flags; /* additional flags for CAN FD */ + __u8 __res0; /* reserved / padding */ + __u8 __res1; /* reserved / padding */ + __u8 data[64] __attribute__((aligned(8))); + }; + +The struct canfd_frame and the existing struct can_frame have the can_id, +the payload length and the payload data at the same offset inside their +structures. This allows to handle the different structures very similar. +When the content of a struct can_frame is copied into a struct canfd_frame +all structure elements can be used as-is - only the data[] becomes extended. + +When introducing the struct canfd_frame it turned out that the data length +code (DLC) of the struct can_frame was used as a length information as the +length and the DLC has a 1:1 mapping in the range of 0 .. 8. To preserve +the easy handling of the length information the canfd_frame.len element +contains a plain length value from 0 .. 64. So both canfd_frame.len and +can_frame.len are equal and contain a length information and no DLC. +For details about the distinction of CAN and CAN FD capable devices and +the mapping to the bus-relevant data length code (DLC), see :ref:`socketcan-can-fd-driver`. + +The length of the two CAN(FD) frame structures define the maximum transfer +unit (MTU) of the CAN(FD) network interface and skbuff data length. Two +definitions are specified for CAN specific MTUs in include/linux/can.h: + +.. code-block:: C + + #define CAN_MTU (sizeof(struct can_frame)) == 16 => Classical CAN frame + #define CANFD_MTU (sizeof(struct canfd_frame)) == 72 => CAN FD frame + + +.. _socketcan-raw-sockets: + +RAW Protocol Sockets with can_filters (SOCK_RAW) +------------------------------------------------ + +Using CAN_RAW sockets is extensively comparable to the commonly +known access to CAN character devices. To meet the new possibilities +provided by the multi user SocketCAN approach, some reasonable +defaults are set at RAW socket binding time: + +- The filters are set to exactly one filter receiving everything +- The socket only receives valid data frames (=> no error message frames) +- The loopback of sent CAN frames is enabled (see :ref:`socketcan-local-loopback2`) +- The socket does not receive its own sent frames (in loopback mode) + +These default settings may be changed before or after binding the socket. +To use the referenced definitions of the socket options for CAN_RAW +sockets, include <linux/can/raw.h>. + + +.. _socketcan-rawfilter: + +RAW socket option CAN_RAW_FILTER +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The reception of CAN frames using CAN_RAW sockets can be controlled +by defining 0 .. n filters with the CAN_RAW_FILTER socket option. + +The CAN filter structure is defined in include/linux/can.h: + +.. code-block:: C + + struct can_filter { + canid_t can_id; + canid_t can_mask; + }; + +A filter matches, when: + +.. code-block:: C + + <received_can_id> & mask == can_id & mask + +which is analogous to known CAN controllers hardware filter semantics. +The filter can be inverted in this semantic, when the CAN_INV_FILTER +bit is set in can_id element of the can_filter structure. In +contrast to CAN controller hardware filters the user may set 0 .. n +receive filters for each open socket separately: + +.. code-block:: C + + struct can_filter rfilter[2]; + + rfilter[0].can_id = 0x123; + rfilter[0].can_mask = CAN_SFF_MASK; + rfilter[1].can_id = 0x200; + rfilter[1].can_mask = 0x700; + + setsockopt(s, SOL_CAN_RAW, CAN_RAW_FILTER, &rfilter, sizeof(rfilter)); + +To disable the reception of CAN frames on the selected CAN_RAW socket: + +.. code-block:: C + + setsockopt(s, SOL_CAN_RAW, CAN_RAW_FILTER, NULL, 0); + +To set the filters to zero filters is quite obsolete as to not read +data causes the raw socket to discard the received CAN frames. But +having this 'send only' use-case we may remove the receive list in the +Kernel to save a little (really a very little!) CPU usage. + +CAN Filter Usage Optimisation +............................. + +The CAN filters are processed in per-device filter lists at CAN frame +reception time. To reduce the number of checks that need to be performed +while walking through the filter lists the CAN core provides an optimized +filter handling when the filter subscription focusses on a single CAN ID. + +For the possible 2048 SFF CAN identifiers the identifier is used as an index +to access the corresponding subscription list without any further checks. +For the 2^29 possible EFF CAN identifiers a 10 bit XOR folding is used as +hash function to retrieve the EFF table index. + +To benefit from the optimized filters for single CAN identifiers the +CAN_SFF_MASK or CAN_EFF_MASK have to be set into can_filter.mask together +with set CAN_EFF_FLAG and CAN_RTR_FLAG bits. A set CAN_EFF_FLAG bit in the +can_filter.mask makes clear that it matters whether a SFF or EFF CAN ID is +subscribed. E.g. in the example from above: + +.. code-block:: C + + rfilter[0].can_id = 0x123; + rfilter[0].can_mask = CAN_SFF_MASK; + +both SFF frames with CAN ID 0x123 and EFF frames with 0xXXXXX123 can pass. + +To filter for only 0x123 (SFF) and 0x12345678 (EFF) CAN identifiers the +filter has to be defined in this way to benefit from the optimized filters: + +.. code-block:: C + + struct can_filter rfilter[2]; + + rfilter[0].can_id = 0x123; + rfilter[0].can_mask = (CAN_EFF_FLAG | CAN_RTR_FLAG | CAN_SFF_MASK); + rfilter[1].can_id = 0x12345678 | CAN_EFF_FLAG; + rfilter[1].can_mask = (CAN_EFF_FLAG | CAN_RTR_FLAG | CAN_EFF_MASK); + + setsockopt(s, SOL_CAN_RAW, CAN_RAW_FILTER, &rfilter, sizeof(rfilter)); + + +RAW Socket Option CAN_RAW_ERR_FILTER +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +As described in :ref:`socketcan-network-problem-notifications` the CAN interface driver can generate so +called Error Message Frames that can optionally be passed to the user +application in the same way as other CAN frames. The possible +errors are divided into different error classes that may be filtered +using the appropriate error mask. To register for every possible +error condition CAN_ERR_MASK can be used as value for the error mask. +The values for the error mask are defined in linux/can/error.h: + +.. code-block:: C + + can_err_mask_t err_mask = ( CAN_ERR_TX_TIMEOUT | CAN_ERR_BUSOFF ); + + setsockopt(s, SOL_CAN_RAW, CAN_RAW_ERR_FILTER, + &err_mask, sizeof(err_mask)); + + +RAW Socket Option CAN_RAW_LOOPBACK +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +To meet multi user needs the local loopback is enabled by default +(see :ref:`socketcan-local-loopback1` for details). But in some embedded use-cases +(e.g. when only one application uses the CAN bus) this loopback +functionality can be disabled (separately for each socket): + +.. code-block:: C + + int loopback = 0; /* 0 = disabled, 1 = enabled (default) */ + + setsockopt(s, SOL_CAN_RAW, CAN_RAW_LOOPBACK, &loopback, sizeof(loopback)); + + +RAW socket option CAN_RAW_RECV_OWN_MSGS +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +When the local loopback is enabled, all the sent CAN frames are +looped back to the open CAN sockets that registered for the CAN +frames' CAN-ID on this given interface to meet the multi user +needs. The reception of the CAN frames on the same socket that was +sending the CAN frame is assumed to be unwanted and therefore +disabled by default. This default behaviour may be changed on +demand: + +.. code-block:: C + + int recv_own_msgs = 1; /* 0 = disabled (default), 1 = enabled */ + + setsockopt(s, SOL_CAN_RAW, CAN_RAW_RECV_OWN_MSGS, + &recv_own_msgs, sizeof(recv_own_msgs)); + +Note that reception of a socket's own CAN frames are subject to the same +filtering as other CAN frames (see :ref:`socketcan-rawfilter`). + +.. _socketcan-rawfd: + +RAW Socket Option CAN_RAW_FD_FRAMES +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +CAN FD support in CAN_RAW sockets can be enabled with a new socket option +CAN_RAW_FD_FRAMES which is off by default. When the new socket option is +not supported by the CAN_RAW socket (e.g. on older kernels), switching the +CAN_RAW_FD_FRAMES option returns the error -ENOPROTOOPT. + +Once CAN_RAW_FD_FRAMES is enabled the application can send both CAN frames +and CAN FD frames. OTOH the application has to handle CAN and CAN FD frames +when reading from the socket: + +.. code-block:: C + + CAN_RAW_FD_FRAMES enabled: CAN_MTU and CANFD_MTU are allowed + CAN_RAW_FD_FRAMES disabled: only CAN_MTU is allowed (default) + +Example: + +.. code-block:: C + + [ remember: CANFD_MTU == sizeof(struct canfd_frame) ] + + struct canfd_frame cfd; + + nbytes = read(s, &cfd, CANFD_MTU); + + if (nbytes == CANFD_MTU) { + printf("got CAN FD frame with length %d\n", cfd.len); + /* cfd.flags contains valid data */ + } else if (nbytes == CAN_MTU) { + printf("got Classical CAN frame with length %d\n", cfd.len); + /* cfd.flags is undefined */ + } else { + fprintf(stderr, "read: invalid CAN(FD) frame\n"); + return 1; + } + + /* the content can be handled independently from the received MTU size */ + + printf("can_id: %X data length: %d data: ", cfd.can_id, cfd.len); + for (i = 0; i < cfd.len; i++) + printf("%02X ", cfd.data[i]); + +When reading with size CANFD_MTU only returns CAN_MTU bytes that have +been received from the socket a Classical CAN frame has been read into the +provided CAN FD structure. Note that the canfd_frame.flags data field is +not specified in the struct can_frame and therefore it is only valid in +CANFD_MTU sized CAN FD frames. + +Implementation hint for new CAN applications: + +To build a CAN FD aware application use struct canfd_frame as basic CAN +data structure for CAN_RAW based applications. When the application is +executed on an older Linux kernel and switching the CAN_RAW_FD_FRAMES +socket option returns an error: No problem. You'll get Classical CAN frames +or CAN FD frames and can process them the same way. + +When sending to CAN devices make sure that the device is capable to handle +CAN FD frames by checking if the device maximum transfer unit is CANFD_MTU. +The CAN device MTU can be retrieved e.g. with a SIOCGIFMTU ioctl() syscall. + + +RAW socket option CAN_RAW_JOIN_FILTERS +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The CAN_RAW socket can set multiple CAN identifier specific filters that +lead to multiple filters in the af_can.c filter processing. These filters +are indenpendent from each other which leads to logical OR'ed filters when +applied (see :ref:`socketcan-rawfilter`). + +This socket option joines the given CAN filters in the way that only CAN +frames are passed to user space that matched *all* given CAN filters. The +semantic for the applied filters is therefore changed to a logical AND. + +This is useful especially when the filterset is a combination of filters +where the CAN_INV_FILTER flag is set in order to notch single CAN IDs or +CAN ID ranges from the incoming traffic. + + +RAW Socket Returned Message Flags +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +When using recvmsg() call, the msg->msg_flags may contain following flags: + +MSG_DONTROUTE: + set when the received frame was created on the local host. + +MSG_CONFIRM: + set when the frame was sent via the socket it is received on. + This flag can be interpreted as a 'transmission confirmation' when the + CAN driver supports the echo of frames on driver level, see + :ref:`socketcan-local-loopback1` and :ref:`socketcan-local-loopback2`. + In order to receive such messages, CAN_RAW_RECV_OWN_MSGS must be set. + + +Broadcast Manager Protocol Sockets (SOCK_DGRAM) +----------------------------------------------- + +The Broadcast Manager protocol provides a command based configuration +interface to filter and send (e.g. cyclic) CAN messages in kernel space. + +Receive filters can be used to down sample frequent messages; detect events +such as message contents changes, packet length changes, and do time-out +monitoring of received messages. + +Periodic transmission tasks of CAN frames or a sequence of CAN frames can be +created and modified at runtime; both the message content and the two +possible transmit intervals can be altered. + +A BCM socket is not intended for sending individual CAN frames using the +struct can_frame as known from the CAN_RAW socket. Instead a special BCM +configuration message is defined. The basic BCM configuration message used +to communicate with the broadcast manager and the available operations are +defined in the linux/can/bcm.h include. The BCM message consists of a +message header with a command ('opcode') followed by zero or more CAN frames. +The broadcast manager sends responses to user space in the same form: + +.. code-block:: C + + struct bcm_msg_head { + __u32 opcode; /* command */ + __u32 flags; /* special flags */ + __u32 count; /* run 'count' times with ival1 */ + struct timeval ival1, ival2; /* count and subsequent interval */ + canid_t can_id; /* unique can_id for task */ + __u32 nframes; /* number of can_frames following */ + struct can_frame frames[0]; + }; + +The aligned payload 'frames' uses the same basic CAN frame structure defined +at the beginning of :ref:`socketcan-rawfd` and in the include/linux/can.h include. All +messages to the broadcast manager from user space have this structure. + +Note a CAN_BCM socket must be connected instead of bound after socket +creation (example without error checking): + +.. code-block:: C + + int s; + struct sockaddr_can addr; + struct ifreq ifr; + + s = socket(PF_CAN, SOCK_DGRAM, CAN_BCM); + + strcpy(ifr.ifr_name, "can0"); + ioctl(s, SIOCGIFINDEX, &ifr); + + addr.can_family = AF_CAN; + addr.can_ifindex = ifr.ifr_ifindex; + + connect(s, (struct sockaddr *)&addr, sizeof(addr)); + + (..) + +The broadcast manager socket is able to handle any number of in flight +transmissions or receive filters concurrently. The different RX/TX jobs are +distinguished by the unique can_id in each BCM message. However additional +CAN_BCM sockets are recommended to communicate on multiple CAN interfaces. +When the broadcast manager socket is bound to 'any' CAN interface (=> the +interface index is set to zero) the configured receive filters apply to any +CAN interface unless the sendto() syscall is used to overrule the 'any' CAN +interface index. When using recvfrom() instead of read() to retrieve BCM +socket messages the originating CAN interface is provided in can_ifindex. + + +Broadcast Manager Operations +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The opcode defines the operation for the broadcast manager to carry out, +or details the broadcast managers response to several events, including +user requests. + +Transmit Operations (user space to broadcast manager): + +TX_SETUP: + Create (cyclic) transmission task. + +TX_DELETE: + Remove (cyclic) transmission task, requires only can_id. + +TX_READ: + Read properties of (cyclic) transmission task for can_id. + +TX_SEND: + Send one CAN frame. + +Transmit Responses (broadcast manager to user space): + +TX_STATUS: + Reply to TX_READ request (transmission task configuration). + +TX_EXPIRED: + Notification when counter finishes sending at initial interval + 'ival1'. Requires the TX_COUNTEVT flag to be set at TX_SETUP. + +Receive Operations (user space to broadcast manager): + +RX_SETUP: + Create RX content filter subscription. + +RX_DELETE: + Remove RX content filter subscription, requires only can_id. + +RX_READ: + Read properties of RX content filter subscription for can_id. + +Receive Responses (broadcast manager to user space): + +RX_STATUS: + Reply to RX_READ request (filter task configuration). + +RX_TIMEOUT: + Cyclic message is detected to be absent (timer ival1 expired). + +RX_CHANGED: + BCM message with updated CAN frame (detected content change). + Sent on first message received or on receipt of revised CAN messages. + + +Broadcast Manager Message Flags +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +When sending a message to the broadcast manager the 'flags' element may +contain the following flag definitions which influence the behaviour: + +SETTIMER: + Set the values of ival1, ival2 and count + +STARTTIMER: + Start the timer with the actual values of ival1, ival2 + and count. Starting the timer leads simultaneously to emit a CAN frame. + +TX_COUNTEVT: + Create the message TX_EXPIRED when count expires + +TX_ANNOUNCE: + A change of data by the process is emitted immediately. + +TX_CP_CAN_ID: + Copies the can_id from the message header to each + subsequent frame in frames. This is intended as usage simplification. For + TX tasks the unique can_id from the message header may differ from the + can_id(s) stored for transmission in the subsequent struct can_frame(s). + +RX_FILTER_ID: + Filter by can_id alone, no frames required (nframes=0). + +RX_CHECK_DLC: + A change of the DLC leads to an RX_CHANGED. + +RX_NO_AUTOTIMER: + Prevent automatically starting the timeout monitor. + +RX_ANNOUNCE_RESUME: + If passed at RX_SETUP and a receive timeout occurred, a + RX_CHANGED message will be generated when the (cyclic) receive restarts. + +TX_RESET_MULTI_IDX: + Reset the index for the multiple frame transmission. + +RX_RTR_FRAME: + Send reply for RTR-request (placed in op->frames[0]). + +CAN_FD_FRAME: + The CAN frames following the bcm_msg_head are struct canfd_frame's + +Broadcast Manager Transmission Timers +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Periodic transmission configurations may use up to two interval timers. +In this case the BCM sends a number of messages ('count') at an interval +'ival1', then continuing to send at another given interval 'ival2'. When +only one timer is needed 'count' is set to zero and only 'ival2' is used. +When SET_TIMER and START_TIMER flag were set the timers are activated. +The timer values can be altered at runtime when only SET_TIMER is set. + + +Broadcast Manager message sequence transmission +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Up to 256 CAN frames can be transmitted in a sequence in the case of a cyclic +TX task configuration. The number of CAN frames is provided in the 'nframes' +element of the BCM message head. The defined number of CAN frames are added +as array to the TX_SETUP BCM configuration message: + +.. code-block:: C + + /* create a struct to set up a sequence of four CAN frames */ + struct { + struct bcm_msg_head msg_head; + struct can_frame frame[4]; + } mytxmsg; + + (..) + mytxmsg.msg_head.nframes = 4; + (..) + + write(s, &mytxmsg, sizeof(mytxmsg)); + +With every transmission the index in the array of CAN frames is increased +and set to zero at index overflow. + + +Broadcast Manager Receive Filter Timers +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The timer values ival1 or ival2 may be set to non-zero values at RX_SETUP. +When the SET_TIMER flag is set the timers are enabled: + +ival1: + Send RX_TIMEOUT when a received message is not received again within + the given time. When START_TIMER is set at RX_SETUP the timeout detection + is activated directly - even without a former CAN frame reception. + +ival2: + Throttle the received message rate down to the value of ival2. This + is useful to reduce messages for the application when the signal inside the + CAN frame is stateless as state changes within the ival2 period may get + lost. + +Broadcast Manager Multiplex Message Receive Filter +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +To filter for content changes in multiplex message sequences an array of more +than one CAN frames can be passed in a RX_SETUP configuration message. The +data bytes of the first CAN frame contain the mask of relevant bits that +have to match in the subsequent CAN frames with the received CAN frame. +If one of the subsequent CAN frames is matching the bits in that frame data +mark the relevant content to be compared with the previous received content. +Up to 257 CAN frames (multiplex filter bit mask CAN frame plus 256 CAN +filters) can be added as array to the TX_SETUP BCM configuration message: + +.. code-block:: C + + /* usually used to clear CAN frame data[] - beware of endian problems! */ + #define U64_DATA(p) (*(unsigned long long*)(p)->data) + + struct { + struct bcm_msg_head msg_head; + struct can_frame frame[5]; + } msg; + + msg.msg_head.opcode = RX_SETUP; + msg.msg_head.can_id = 0x42; + msg.msg_head.flags = 0; + msg.msg_head.nframes = 5; + U64_DATA(&msg.frame[0]) = 0xFF00000000000000ULL; /* MUX mask */ + U64_DATA(&msg.frame[1]) = 0x01000000000000FFULL; /* data mask (MUX 0x01) */ + U64_DATA(&msg.frame[2]) = 0x0200FFFF000000FFULL; /* data mask (MUX 0x02) */ + U64_DATA(&msg.frame[3]) = 0x330000FFFFFF0003ULL; /* data mask (MUX 0x33) */ + U64_DATA(&msg.frame[4]) = 0x4F07FC0FF0000000ULL; /* data mask (MUX 0x4F) */ + + write(s, &msg, sizeof(msg)); + + +Broadcast Manager CAN FD Support +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The programming API of the CAN_BCM depends on struct can_frame which is +given as array directly behind the bcm_msg_head structure. To follow this +schema for the CAN FD frames a new flag 'CAN_FD_FRAME' in the bcm_msg_head +flags indicates that the concatenated CAN frame structures behind the +bcm_msg_head are defined as struct canfd_frame: + +.. code-block:: C + + struct { + struct bcm_msg_head msg_head; + struct canfd_frame frame[5]; + } msg; + + msg.msg_head.opcode = RX_SETUP; + msg.msg_head.can_id = 0x42; + msg.msg_head.flags = CAN_FD_FRAME; + msg.msg_head.nframes = 5; + (..) + +When using CAN FD frames for multiplex filtering the MUX mask is still +expected in the first 64 bit of the struct canfd_frame data section. + + +Connected Transport Protocols (SOCK_SEQPACKET) +---------------------------------------------- + +(to be written) + + +Unconnected Transport Protocols (SOCK_DGRAM) +-------------------------------------------- + +(to be written) + + +.. _socketcan-core-module: + +SocketCAN Core Module +===================== + +The SocketCAN core module implements the protocol family +PF_CAN. CAN protocol modules are loaded by the core module at +runtime. The core module provides an interface for CAN protocol +modules to subscribe needed CAN IDs (see :ref:`socketcan-receive-lists`). + + +can.ko Module Params +-------------------- + +- **stats_timer**: + To calculate the SocketCAN core statistics + (e.g. current/maximum frames per second) this 1 second timer is + invoked at can.ko module start time by default. This timer can be + disabled by using stattimer=0 on the module commandline. + +- **debug**: + (removed since SocketCAN SVN r546) + + +procfs content +-------------- + +As described in :ref:`socketcan-receive-lists` the SocketCAN core uses several filter +lists to deliver received CAN frames to CAN protocol modules. These +receive lists, their filters and the count of filter matches can be +checked in the appropriate receive list. All entries contain the +device and a protocol module identifier:: + + foo@bar:~$ cat /proc/net/can/rcvlist_all + + receive list 'rx_all': + (vcan3: no entry) + (vcan2: no entry) + (vcan1: no entry) + device can_id can_mask function userdata matches ident + vcan0 000 00000000 f88e6370 f6c6f400 0 raw + (any: no entry) + +In this example an application requests any CAN traffic from vcan0:: + + rcvlist_all - list for unfiltered entries (no filter operations) + rcvlist_eff - list for single extended frame (EFF) entries + rcvlist_err - list for error message frames masks + rcvlist_fil - list for mask/value filters + rcvlist_inv - list for mask/value filters (inverse semantic) + rcvlist_sff - list for single standard frame (SFF) entries + +Additional procfs files in /proc/net/can:: + + stats - SocketCAN core statistics (rx/tx frames, match ratios, ...) + reset_stats - manual statistic reset + version - prints SocketCAN core and ABI version (removed in Linux 5.10) + + +Writing Own CAN Protocol Modules +-------------------------------- + +To implement a new protocol in the protocol family PF_CAN a new +protocol has to be defined in include/linux/can.h . +The prototypes and definitions to use the SocketCAN core can be +accessed by including include/linux/can/core.h . +In addition to functions that register the CAN protocol and the +CAN device notifier chain there are functions to subscribe CAN +frames received by CAN interfaces and to send CAN frames:: + + can_rx_register - subscribe CAN frames from a specific interface + can_rx_unregister - unsubscribe CAN frames from a specific interface + can_send - transmit a CAN frame (optional with local loopback) + +For details see the kerneldoc documentation in net/can/af_can.c or +the source code of net/can/raw.c or net/can/bcm.c . + + +CAN Network Drivers +=================== + +Writing a CAN network device driver is much easier than writing a +CAN character device driver. Similar to other known network device +drivers you mainly have to deal with: + +- TX: Put the CAN frame from the socket buffer to the CAN controller. +- RX: Put the CAN frame from the CAN controller to the socket buffer. + +See e.g. at Documentation/networking/netdevices.rst . The differences +for writing CAN network device driver are described below: + + +General Settings +---------------- + +.. code-block:: C + + dev->type = ARPHRD_CAN; /* the netdevice hardware type */ + dev->flags = IFF_NOARP; /* CAN has no arp */ + + dev->mtu = CAN_MTU; /* sizeof(struct can_frame) -> Classical CAN interface */ + + or alternative, when the controller supports CAN with flexible data rate: + dev->mtu = CANFD_MTU; /* sizeof(struct canfd_frame) -> CAN FD interface */ + +The struct can_frame or struct canfd_frame is the payload of each socket +buffer (skbuff) in the protocol family PF_CAN. + + +.. _socketcan-local-loopback2: + +Local Loopback of Sent Frames +----------------------------- + +As described in :ref:`socketcan-local-loopback1` the CAN network device driver should +support a local loopback functionality similar to the local echo +e.g. of tty devices. In this case the driver flag IFF_ECHO has to be +set to prevent the PF_CAN core from locally echoing sent frames +(aka loopback) as fallback solution:: + + dev->flags = (IFF_NOARP | IFF_ECHO); + + +CAN Controller Hardware Filters +------------------------------- + +To reduce the interrupt load on deep embedded systems some CAN +controllers support the filtering of CAN IDs or ranges of CAN IDs. +These hardware filter capabilities vary from controller to +controller and have to be identified as not feasible in a multi-user +networking approach. The use of the very controller specific +hardware filters could make sense in a very dedicated use-case, as a +filter on driver level would affect all users in the multi-user +system. The high efficient filter sets inside the PF_CAN core allow +to set different multiple filters for each socket separately. +Therefore the use of hardware filters goes to the category 'handmade +tuning on deep embedded systems'. The author is running a MPC603e +@133MHz with four SJA1000 CAN controllers from 2002 under heavy bus +load without any problems ... + + +Switchable Termination Resistors +-------------------------------- + +CAN bus requires a specific impedance across the differential pair, +typically provided by two 120Ohm resistors on the farthest nodes of +the bus. Some CAN controllers support activating / deactivating a +termination resistor(s) to provide the correct impedance. + +Query the available resistances:: + + $ ip -details link show can0 + ... + termination 120 [ 0, 120 ] + +Activate the terminating resistor:: + + $ ip link set dev can0 type can termination 120 + +Deactivate the terminating resistor:: + + $ ip link set dev can0 type can termination 0 + +To enable termination resistor support to a can-controller, either +implement in the controller's struct can-priv:: + + termination_const + termination_const_cnt + do_set_termination + +or add gpio control with the device tree entries from +Documentation/devicetree/bindings/net/can/can-controller.yaml + + +The Virtual CAN Driver (vcan) +----------------------------- + +Similar to the network loopback devices, vcan offers a virtual local +CAN interface. A full qualified address on CAN consists of + +- a unique CAN Identifier (CAN ID) +- the CAN bus this CAN ID is transmitted on (e.g. can0) + +so in common use cases more than one virtual CAN interface is needed. + +The virtual CAN interfaces allow the transmission and reception of CAN +frames without real CAN controller hardware. Virtual CAN network +devices are usually named 'vcanX', like vcan0 vcan1 vcan2 ... +When compiled as a module the virtual CAN driver module is called vcan.ko + +Since Linux Kernel version 2.6.24 the vcan driver supports the Kernel +netlink interface to create vcan network devices. The creation and +removal of vcan network devices can be managed with the ip(8) tool:: + + - Create a virtual CAN network interface: + $ ip link add type vcan + + - Create a virtual CAN network interface with a specific name 'vcan42': + $ ip link add dev vcan42 type vcan + + - Remove a (virtual CAN) network interface 'vcan42': + $ ip link del vcan42 + + +The CAN Network Device Driver Interface +--------------------------------------- + +The CAN network device driver interface provides a generic interface +to setup, configure and monitor CAN network devices. The user can then +configure the CAN device, like setting the bit-timing parameters, via +the netlink interface using the program "ip" from the "IPROUTE2" +utility suite. The following chapter describes briefly how to use it. +Furthermore, the interface uses a common data structure and exports a +set of common functions, which all real CAN network device drivers +should use. Please have a look to the SJA1000 or MSCAN driver to +understand how to use them. The name of the module is can-dev.ko. + + +Netlink interface to set/get devices properties +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The CAN device must be configured via netlink interface. The supported +netlink message types are defined and briefly described in +"include/linux/can/netlink.h". CAN link support for the program "ip" +of the IPROUTE2 utility suite is available and it can be used as shown +below: + +Setting CAN device properties:: + + $ ip link set can0 type can help + Usage: ip link set DEVICE type can + [ bitrate BITRATE [ sample-point SAMPLE-POINT] ] | + [ tq TQ prop-seg PROP_SEG phase-seg1 PHASE-SEG1 + phase-seg2 PHASE-SEG2 [ sjw SJW ] ] + + [ dbitrate BITRATE [ dsample-point SAMPLE-POINT] ] | + [ dtq TQ dprop-seg PROP_SEG dphase-seg1 PHASE-SEG1 + dphase-seg2 PHASE-SEG2 [ dsjw SJW ] ] + + [ loopback { on | off } ] + [ listen-only { on | off } ] + [ triple-sampling { on | off } ] + [ one-shot { on | off } ] + [ berr-reporting { on | off } ] + [ fd { on | off } ] + [ fd-non-iso { on | off } ] + [ presume-ack { on | off } ] + [ cc-len8-dlc { on | off } ] + + [ restart-ms TIME-MS ] + [ restart ] + + Where: BITRATE := { 1..1000000 } + SAMPLE-POINT := { 0.000..0.999 } + TQ := { NUMBER } + PROP-SEG := { 1..8 } + PHASE-SEG1 := { 1..8 } + PHASE-SEG2 := { 1..8 } + SJW := { 1..4 } + RESTART-MS := { 0 | NUMBER } + +Display CAN device details and statistics:: + + $ ip -details -statistics link show can0 + 2: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UP qlen 10 + link/can + can <TRIPLE-SAMPLING> state ERROR-ACTIVE restart-ms 100 + bitrate 125000 sample_point 0.875 + tq 125 prop-seg 6 phase-seg1 7 phase-seg2 2 sjw 1 + sja1000: tseg1 1..16 tseg2 1..8 sjw 1..4 brp 1..64 brp-inc 1 + clock 8000000 + re-started bus-errors arbit-lost error-warn error-pass bus-off + 41 17457 0 41 42 41 + RX: bytes packets errors dropped overrun mcast + 140859 17608 17457 0 0 0 + TX: bytes packets errors dropped carrier collsns + 861 112 0 41 0 0 + +More info to the above output: + +"<TRIPLE-SAMPLING>" + Shows the list of selected CAN controller modes: LOOPBACK, + LISTEN-ONLY, or TRIPLE-SAMPLING. + +"state ERROR-ACTIVE" + The current state of the CAN controller: "ERROR-ACTIVE", + "ERROR-WARNING", "ERROR-PASSIVE", "BUS-OFF" or "STOPPED" + +"restart-ms 100" + Automatic restart delay time. If set to a non-zero value, a + restart of the CAN controller will be triggered automatically + in case of a bus-off condition after the specified delay time + in milliseconds. By default it's off. + +"bitrate 125000 sample-point 0.875" + Shows the real bit-rate in bits/sec and the sample-point in the + range 0.000..0.999. If the calculation of bit-timing parameters + is enabled in the kernel (CONFIG_CAN_CALC_BITTIMING=y), the + bit-timing can be defined by setting the "bitrate" argument. + Optionally the "sample-point" can be specified. By default it's + 0.000 assuming CIA-recommended sample-points. + +"tq 125 prop-seg 6 phase-seg1 7 phase-seg2 2 sjw 1" + Shows the time quanta in ns, propagation segment, phase buffer + segment 1 and 2 and the synchronisation jump width in units of + tq. They allow to define the CAN bit-timing in a hardware + independent format as proposed by the Bosch CAN 2.0 spec (see + chapter 8 of http://www.semiconductors.bosch.de/pdf/can2spec.pdf). + +"sja1000: tseg1 1..16 tseg2 1..8 sjw 1..4 brp 1..64 brp-inc 1 clock 8000000" + Shows the bit-timing constants of the CAN controller, here the + "sja1000". The minimum and maximum values of the time segment 1 + and 2, the synchronisation jump width in units of tq, the + bitrate pre-scaler and the CAN system clock frequency in Hz. + These constants could be used for user-defined (non-standard) + bit-timing calculation algorithms in user-space. + +"re-started bus-errors arbit-lost error-warn error-pass bus-off" + Shows the number of restarts, bus and arbitration lost errors, + and the state changes to the error-warning, error-passive and + bus-off state. RX overrun errors are listed in the "overrun" + field of the standard network statistics. + +Setting the CAN Bit-Timing +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The CAN bit-timing parameters can always be defined in a hardware +independent format as proposed in the Bosch CAN 2.0 specification +specifying the arguments "tq", "prop_seg", "phase_seg1", "phase_seg2" +and "sjw":: + + $ ip link set canX type can tq 125 prop-seg 6 \ + phase-seg1 7 phase-seg2 2 sjw 1 + +If the kernel option CONFIG_CAN_CALC_BITTIMING is enabled, CIA +recommended CAN bit-timing parameters will be calculated if the bit- +rate is specified with the argument "bitrate":: + + $ ip link set canX type can bitrate 125000 + +Note that this works fine for the most common CAN controllers with +standard bit-rates but may *fail* for exotic bit-rates or CAN system +clock frequencies. Disabling CONFIG_CAN_CALC_BITTIMING saves some +space and allows user-space tools to solely determine and set the +bit-timing parameters. The CAN controller specific bit-timing +constants can be used for that purpose. They are listed by the +following command:: + + $ ip -details link show can0 + ... + sja1000: clock 8000000 tseg1 1..16 tseg2 1..8 sjw 1..4 brp 1..64 brp-inc 1 + + +Starting and Stopping the CAN Network Device +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +A CAN network device is started or stopped as usual with the command +"ifconfig canX up/down" or "ip link set canX up/down". Be aware that +you *must* define proper bit-timing parameters for real CAN devices +before you can start it to avoid error-prone default settings:: + + $ ip link set canX up type can bitrate 125000 + +A device may enter the "bus-off" state if too many errors occurred on +the CAN bus. Then no more messages are received or sent. An automatic +bus-off recovery can be enabled by setting the "restart-ms" to a +non-zero value, e.g.:: + + $ ip link set canX type can restart-ms 100 + +Alternatively, the application may realize the "bus-off" condition +by monitoring CAN error message frames and do a restart when +appropriate with the command:: + + $ ip link set canX type can restart + +Note that a restart will also create a CAN error message frame (see +also :ref:`socketcan-network-problem-notifications`). + + +.. _socketcan-can-fd-driver: + +CAN FD (Flexible Data Rate) Driver Support +------------------------------------------ + +CAN FD capable CAN controllers support two different bitrates for the +arbitration phase and the payload phase of the CAN FD frame. Therefore a +second bit timing has to be specified in order to enable the CAN FD bitrate. + +Additionally CAN FD capable CAN controllers support up to 64 bytes of +payload. The representation of this length in can_frame.len and +canfd_frame.len for userspace applications and inside the Linux network +layer is a plain value from 0 .. 64 instead of the CAN 'data length code'. +The data length code was a 1:1 mapping to the payload length in the Classical +CAN frames anyway. The payload length to the bus-relevant DLC mapping is +only performed inside the CAN drivers, preferably with the helper +functions can_fd_dlc2len() and can_fd_len2dlc(). + +The CAN netdevice driver capabilities can be distinguished by the network +devices maximum transfer unit (MTU):: + + MTU = 16 (CAN_MTU) => sizeof(struct can_frame) => Classical CAN device + MTU = 72 (CANFD_MTU) => sizeof(struct canfd_frame) => CAN FD capable device + +The CAN device MTU can be retrieved e.g. with a SIOCGIFMTU ioctl() syscall. +N.B. CAN FD capable devices can also handle and send Classical CAN frames. + +When configuring CAN FD capable CAN controllers an additional 'data' bitrate +has to be set. This bitrate for the data phase of the CAN FD frame has to be +at least the bitrate which was configured for the arbitration phase. This +second bitrate is specified analogue to the first bitrate but the bitrate +setting keywords for the 'data' bitrate start with 'd' e.g. dbitrate, +dsample-point, dsjw or dtq and similar settings. When a data bitrate is set +within the configuration process the controller option "fd on" can be +specified to enable the CAN FD mode in the CAN controller. This controller +option also switches the device MTU to 72 (CANFD_MTU). + +The first CAN FD specification presented as whitepaper at the International +CAN Conference 2012 needed to be improved for data integrity reasons. +Therefore two CAN FD implementations have to be distinguished today: + +- ISO compliant: The ISO 11898-1:2015 CAN FD implementation (default) +- non-ISO compliant: The CAN FD implementation following the 2012 whitepaper + +Finally there are three types of CAN FD controllers: + +1. ISO compliant (fixed) +2. non-ISO compliant (fixed, like the M_CAN IP core v3.0.1 in m_can.c) +3. ISO/non-ISO CAN FD controllers (switchable, like the PEAK PCAN-USB FD) + +The current ISO/non-ISO mode is announced by the CAN controller driver via +netlink and displayed by the 'ip' tool (controller option FD-NON-ISO). +The ISO/non-ISO-mode can be altered by setting 'fd-non-iso {on|off}' for +switchable CAN FD controllers only. + +Example configuring 500 kbit/s arbitration bitrate and 4 Mbit/s data bitrate:: + + $ ip link set can0 up type can bitrate 500000 sample-point 0.75 \ + dbitrate 4000000 dsample-point 0.8 fd on + $ ip -details link show can0 + 5: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 72 qdisc pfifo_fast state UNKNOWN \ + mode DEFAULT group default qlen 10 + link/can promiscuity 0 + can <FD> state ERROR-ACTIVE (berr-counter tx 0 rx 0) restart-ms 0 + bitrate 500000 sample-point 0.750 + tq 50 prop-seg 14 phase-seg1 15 phase-seg2 10 sjw 1 + pcan_usb_pro_fd: tseg1 1..64 tseg2 1..16 sjw 1..16 brp 1..1024 \ + brp-inc 1 + dbitrate 4000000 dsample-point 0.800 + dtq 12 dprop-seg 7 dphase-seg1 8 dphase-seg2 4 dsjw 1 + pcan_usb_pro_fd: dtseg1 1..16 dtseg2 1..8 dsjw 1..4 dbrp 1..1024 \ + dbrp-inc 1 + clock 80000000 + +Example when 'fd-non-iso on' is added on this switchable CAN FD adapter:: + + can <FD,FD-NON-ISO> state ERROR-ACTIVE (berr-counter tx 0 rx 0) restart-ms 0 + + +Supported CAN Hardware +---------------------- + +Please check the "Kconfig" file in "drivers/net/can" to get an actual +list of the support CAN hardware. On the SocketCAN project website +(see :ref:`socketcan-resources`) there might be further drivers available, also for +older kernel versions. + + +.. _socketcan-resources: + +SocketCAN Resources +=================== + +The Linux CAN / SocketCAN project resources (project site / mailing list) +are referenced in the MAINTAINERS file in the Linux source tree. +Search for CAN NETWORK [LAYERS|DRIVERS]. + +Credits +======= + +- Oliver Hartkopp (PF_CAN core, filters, drivers, bcm, SJA1000 driver) +- Urs Thuermann (PF_CAN core, kernel integration, socket interfaces, raw, vcan) +- Jan Kizka (RT-SocketCAN core, Socket-API reconciliation) +- Wolfgang Grandegger (RT-SocketCAN core & drivers, Raw Socket-API reviews, CAN device driver interface, MSCAN driver) +- Robert Schwebel (design reviews, PTXdist integration) +- Marc Kleine-Budde (design reviews, Kernel 2.6 cleanups, drivers) +- Benedikt Spranger (reviews) +- Thomas Gleixner (LKML reviews, coding style, posting hints) +- Andrey Volkov (kernel subtree structure, ioctls, MSCAN driver) +- Matthias Brukner (first SJA1000 CAN netdevice implementation Q2/2003) +- Klaus Hitschler (PEAK driver integration) +- Uwe Koppe (CAN netdevices with PF_PACKET approach) +- Michael Schulze (driver layer loopback requirement, RT CAN drivers review) +- Pavel Pisa (Bit-timing calculation) +- Sascha Hauer (SJA1000 platform driver) +- Sebastian Haas (SJA1000 EMS PCI driver) +- Markus Plessing (SJA1000 EMS PCI driver) +- Per Dalen (SJA1000 Kvaser PCI driver) +- Sam Ravnborg (reviews, coding style, kbuild help) diff --git a/Documentation/networking/can_ucan_protocol.rst b/Documentation/networking/can_ucan_protocol.rst new file mode 100644 index 0000000000..935d872ae8 --- /dev/null +++ b/Documentation/networking/can_ucan_protocol.rst @@ -0,0 +1,332 @@ +================= +The UCAN Protocol +================= + +UCAN is the protocol used by the microcontroller-based USB-CAN +adapter that is integrated on System-on-Modules from Theobroma Systems +and that is also available as a standalone USB stick. + +The UCAN protocol has been designed to be hardware-independent. +It is modeled closely after how Linux represents CAN devices +internally. All multi-byte integers are encoded as Little Endian. + +All structures mentioned in this document are defined in +``drivers/net/can/usb/ucan.c``. + +USB Endpoints +============= + +UCAN devices use three USB endpoints: + +CONTROL endpoint + The driver sends device management commands on this endpoint + +IN endpoint + The device sends CAN data frames and CAN error frames + +OUT endpoint + The driver sends CAN data frames on the out endpoint + + +CONTROL Messages +================ + +UCAN devices are configured using vendor requests on the control pipe. + +To support multiple CAN interfaces in a single USB device all +configuration commands target the corresponding interface in the USB +descriptor. + +The driver uses ``ucan_ctrl_command_in/out`` and +``ucan_device_request_in`` to deliver commands to the device. + +Setup Packet +------------ + +================= ===================================================== +``bmRequestType`` Direction | Vendor | (Interface or Device) +``bRequest`` Command Number +``wValue`` Subcommand Number (16 Bit) or 0 if not used +``wIndex`` USB Interface Index (0 for device commands) +``wLength`` * Host to Device - Number of bytes to transmit + * Device to Host - Maximum Number of bytes to + receive. If the device send less. Common ZLP + semantics are used. +================= ===================================================== + +Error Handling +-------------- + +The device indicates failed control commands by stalling the +pipe. + +Device Commands +--------------- + +UCAN_DEVICE_GET_FW_STRING +~~~~~~~~~~~~~~~~~~~~~~~~~ + +*Dev2Host; optional* + +Request the device firmware string. + + +Interface Commands +------------------ + +UCAN_COMMAND_START +~~~~~~~~~~~~~~~~~~ + +*Host2Dev; mandatory* + +Bring the CAN interface up. + +Payload Format + ``ucan_ctl_payload_t.cmd_start`` + +==== ============================ +mode or mask of ``UCAN_MODE_*`` +==== ============================ + +UCAN_COMMAND_STOP +~~~~~~~~~~~~~~~~~~ + +*Host2Dev; mandatory* + +Stop the CAN interface + +Payload Format + *empty* + +UCAN_COMMAND_RESET +~~~~~~~~~~~~~~~~~~ + +*Host2Dev; mandatory* + +Reset the CAN controller (including error counters) + +Payload Format + *empty* + +UCAN_COMMAND_GET +~~~~~~~~~~~~~~~~ + +*Host2Dev; mandatory* + +Get Information from the Device + +Subcommands +^^^^^^^^^^^ + +UCAN_COMMAND_GET_INFO + Request the device information structure ``ucan_ctl_payload_t.device_info``. + + See the ``device_info`` field for details, and + ``uapi/linux/can/netlink.h`` for an explanation of the + ``can_bittiming fields``. + + Payload Format + ``ucan_ctl_payload_t.device_info`` + +UCAN_COMMAND_GET_PROTOCOL_VERSION + + Request the device protocol version + ``ucan_ctl_payload_t.protocol_version``. The current protocol version is 3. + + Payload Format + ``ucan_ctl_payload_t.protocol_version`` + +.. note:: Devices that do not implement this command use the old + protocol version 1 + +UCAN_COMMAND_SET_BITTIMING +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +*Host2Dev; mandatory* + +Setup bittiming by sending the structure +``ucan_ctl_payload_t.cmd_set_bittiming`` (see ``struct bittiming`` for +details) + +Payload Format + ``ucan_ctl_payload_t.cmd_set_bittiming``. + +UCAN_SLEEP/WAKE +~~~~~~~~~~~~~~~ + +*Host2Dev; optional* + +Configure sleep and wake modes. Not yet supported by the driver. + +UCAN_FILTER +~~~~~~~~~~~ + +*Host2Dev; optional* + +Setup hardware CAN filters. Not yet supported by the driver. + +Allowed interface commands +-------------------------- + +================== =================== ================== +Legal Device State Command New Device State +================== =================== ================== +stopped SET_BITTIMING stopped +stopped START started +started STOP or RESET stopped +stopped STOP or RESET stopped +started RESTART started +any GET *no change* +================== =================== ================== + +IN Message Format +================= + +A data packet on the USB IN endpoint contains one or more +``ucan_message_in`` values. If multiple messages are batched in a USB +data packet, the ``len`` field can be used to jump to the next +``ucan_message_in`` value (take care to sanity-check the ``len`` value +against the actual data size). + +.. _can_ucan_in_message_len: + +``len`` field +------------- + +Each ``ucan_message_in`` must be aligned to a 4-byte boundary (relative +to the start of the start of the data buffer). That means that there +may be padding bytes between multiple ``ucan_message_in`` values: + +.. code:: + + +----------------------------+ < 0 + | | + | struct ucan_message_in | + | | + +----------------------------+ < len + [padding] + +----------------------------+ < round_up(len, 4) + | | + | struct ucan_message_in | + | | + +----------------------------+ + [...] + +``type`` field +-------------- + +The ``type`` field specifies the type of the message. + +UCAN_IN_RX +~~~~~~~~~~ + +``subtype`` + zero + +Data received from the CAN bus (ID + payload). + +UCAN_IN_TX_COMPLETE +~~~~~~~~~~~~~~~~~~~ + +``subtype`` + zero + +The CAN device has sent a message to the CAN bus. It answers with a +list of tuples <echo-ids, flags>. + +The echo-id identifies the frame from (echos the id from a previous +UCAN_OUT_TX message). The flag indicates the result of the +transmission. Whereas a set Bit 0 indicates success. All other bits +are reserved and set to zero. + +Flow Control +------------ + +When receiving CAN messages there is no flow control on the USB +buffer. The driver has to handle inbound message quickly enough to +avoid drops. I case the device buffer overflow the condition is +reported by sending corresponding error frames (see +:ref:`can_ucan_error_handling`) + + +OUT Message Format +================== + +A data packet on the USB OUT endpoint contains one or more ``struct +ucan_message_out`` values. If multiple messages are batched into one +data packet, the device uses the ``len`` field to jump to the next +ucan_message_out value. Each ucan_message_out must be aligned to 4 +bytes (relative to the start of the data buffer). The mechanism is +same as described in :ref:`can_ucan_in_message_len`. + +.. code:: + + +----------------------------+ < 0 + | | + | struct ucan_message_out | + | | + +----------------------------+ < len + [padding] + +----------------------------+ < round_up(len, 4) + | | + | struct ucan_message_out | + | | + +----------------------------+ + [...] + +``type`` field +-------------- + +In protocol version 3 only ``UCAN_OUT_TX`` is defined, others are used +only by legacy devices (protocol version 1). + +UCAN_OUT_TX +~~~~~~~~~~~ +``subtype`` + echo id to be replied within a CAN_IN_TX_COMPLETE message + +Transmit a CAN frame. (parameters: ``id``, ``data``) + +Flow Control +------------ + +When the device outbound buffers are full it starts sending *NAKs* on +the *OUT* pipe until more buffers are available. The driver stops the +queue when a certain threshold of out packets are incomplete. + +.. _can_ucan_error_handling: + +CAN Error Handling +================== + +If error reporting is turned on the device encodes errors into CAN +error frames (see ``uapi/linux/can/error.h``) and sends it using the +IN endpoint. The driver updates its error statistics and forwards +it. + +Although UCAN devices can suppress error frames completely, in Linux +the driver is always interested. Hence, the device is always started with +the ``UCAN_MODE_BERR_REPORT`` set. Filtering those messages for the +user space is done by the driver. + +Bus OFF +------- + +- The device does not recover from bus of automatically. +- Bus OFF is indicated by an error frame (see ``uapi/linux/can/error.h``) +- Bus OFF recovery is started by ``UCAN_COMMAND_RESTART`` +- Once Bus OFF recover is completed the device sends an error frame + indicating that it is on ERROR-ACTIVE state. +- During Bus OFF no frames are sent by the device. +- During Bus OFF transmission requests from the host are completed + immediately with the success bit left unset. + +Example Conversation +==================== + +#) Device is connected to USB +#) Host sends command ``UCAN_COMMAND_RESET``, subcmd 0 +#) Host sends command ``UCAN_COMMAND_GET``, subcmd ``UCAN_COMMAND_GET_INFO`` +#) Device sends ``UCAN_IN_DEVICE_INFO`` +#) Host sends command ``UCAN_OUT_SET_BITTIMING`` +#) Host sends command ``UCAN_COMMAND_START``, subcmd 0, mode ``UCAN_MODE_BERR_REPORT`` diff --git a/Documentation/networking/cdc_mbim.rst b/Documentation/networking/cdc_mbim.rst new file mode 100644 index 0000000000..37f968acc4 --- /dev/null +++ b/Documentation/networking/cdc_mbim.rst @@ -0,0 +1,355 @@ +.. SPDX-License-Identifier: GPL-2.0 + +====================================================== +cdc_mbim - Driver for CDC MBIM Mobile Broadband modems +====================================================== + +The cdc_mbim driver supports USB devices conforming to the "Universal +Serial Bus Communications Class Subclass Specification for Mobile +Broadband Interface Model" [1], which is a further development of +"Universal Serial Bus Communications Class Subclass Specifications for +Network Control Model Devices" [2] optimized for Mobile Broadband +devices, aka "3G/LTE modems". + + +Command Line Parameters +======================= + +The cdc_mbim driver has no parameters of its own. But the probing +behaviour for NCM 1.0 backwards compatible MBIM functions (an +"NCM/MBIM function" as defined in section 3.2 of [1]) is affected +by a cdc_ncm driver parameter: + +prefer_mbim +----------- +:Type: Boolean +:Valid Range: N/Y (0-1) +:Default Value: Y (MBIM is preferred) + +This parameter sets the system policy for NCM/MBIM functions. Such +functions will be handled by either the cdc_ncm driver or the cdc_mbim +driver depending on the prefer_mbim setting. Setting prefer_mbim=N +makes the cdc_mbim driver ignore these functions and lets the cdc_ncm +driver handle them instead. + +The parameter is writable, and can be changed at any time. A manual +unbind/bind is required to make the change effective for NCM/MBIM +functions bound to the "wrong" driver + + +Basic usage +=========== + +MBIM functions are inactive when unmanaged. The cdc_mbim driver only +provides a userspace interface to the MBIM control channel, and will +not participate in the management of the function. This implies that a +userspace MBIM management application always is required to enable a +MBIM function. + +Such userspace applications includes, but are not limited to: + + - mbimcli (included with the libmbim [3] library), and + - ModemManager [4] + +Establishing a MBIM IP session reequires at least these actions by the +management application: + + - open the control channel + - configure network connection settings + - connect to network + - configure IP interface + +Management application development +---------------------------------- +The driver <-> userspace interfaces are described below. The MBIM +control channel protocol is described in [1]. + + +MBIM control channel userspace ABI +================================== + +/dev/cdc-wdmX character device +------------------------------ +The driver creates a two-way pipe to the MBIM function control channel +using the cdc-wdm driver as a subdriver. The userspace end of the +control channel pipe is a /dev/cdc-wdmX character device. + +The cdc_mbim driver does not process or police messages on the control +channel. The channel is fully delegated to the userspace management +application. It is therefore up to this application to ensure that it +complies with all the control channel requirements in [1]. + +The cdc-wdmX device is created as a child of the MBIM control +interface USB device. The character device associated with a specific +MBIM function can be looked up using sysfs. For example:: + + bjorn@nemi:~$ ls /sys/bus/usb/drivers/cdc_mbim/2-4:2.12/usbmisc + cdc-wdm0 + + bjorn@nemi:~$ grep . /sys/bus/usb/drivers/cdc_mbim/2-4:2.12/usbmisc/cdc-wdm0/dev + 180:0 + + +USB configuration descriptors +----------------------------- +The wMaxControlMessage field of the CDC MBIM functional descriptor +limits the maximum control message size. The management application is +responsible for negotiating a control message size complying with the +requirements in section 9.3.1 of [1], taking this descriptor field +into consideration. + +The userspace application can access the CDC MBIM functional +descriptor of a MBIM function using either of the two USB +configuration descriptor kernel interfaces described in [6] or [7]. + +See also the ioctl documentation below. + + +Fragmentation +------------- +The userspace application is responsible for all control message +fragmentation and defragmentaion, as described in section 9.5 of [1]. + + +/dev/cdc-wdmX write() +--------------------- +The MBIM control messages from the management application *must not* +exceed the negotiated control message size. + + +/dev/cdc-wdmX read() +-------------------- +The management application *must* accept control messages of up the +negotiated control message size. + + +/dev/cdc-wdmX ioctl() +--------------------- +IOCTL_WDM_MAX_COMMAND: Get Maximum Command Size +This ioctl returns the wMaxControlMessage field of the CDC MBIM +functional descriptor for MBIM devices. This is intended as a +convenience, eliminating the need to parse the USB descriptors from +userspace. + +:: + + #include <stdio.h> + #include <fcntl.h> + #include <sys/ioctl.h> + #include <linux/types.h> + #include <linux/usb/cdc-wdm.h> + int main() + { + __u16 max; + int fd = open("/dev/cdc-wdm0", O_RDWR); + if (!ioctl(fd, IOCTL_WDM_MAX_COMMAND, &max)) + printf("wMaxControlMessage is %d\n", max); + } + + +Custom device services +---------------------- +The MBIM specification allows vendors to freely define additional +services. This is fully supported by the cdc_mbim driver. + +Support for new MBIM services, including vendor specified services, is +implemented entirely in userspace, like the rest of the MBIM control +protocol + +New services should be registered in the MBIM Registry [5]. + + + +MBIM data channel userspace ABI +=============================== + +wwanY network device +-------------------- +The cdc_mbim driver represents the MBIM data channel as a single +network device of the "wwan" type. This network device is initially +mapped to MBIM IP session 0. + + +Multiplexed IP sessions (IPS) +----------------------------- +MBIM allows multiplexing up to 256 IP sessions over a single USB data +channel. The cdc_mbim driver models such IP sessions as 802.1q VLAN +subdevices of the master wwanY device, mapping MBIM IP session Z to +VLAN ID Z for all values of Z greater than 0. + +The device maximum Z is given in the MBIM_DEVICE_CAPS_INFO structure +described in section 10.5.1 of [1]. + +The userspace management application is responsible for adding new +VLAN links prior to establishing MBIM IP sessions where the SessionId +is greater than 0. These links can be added by using the normal VLAN +kernel interfaces, either ioctl or netlink. + +For example, adding a link for a MBIM IP session with SessionId 3:: + + ip link add link wwan0 name wwan0.3 type vlan id 3 + +The driver will automatically map the "wwan0.3" network device to MBIM +IP session 3. + + +Device Service Streams (DSS) +---------------------------- +MBIM also allows up to 256 non-IP data streams to be multiplexed over +the same shared USB data channel. The cdc_mbim driver models these +sessions as another set of 802.1q VLAN subdevices of the master wwanY +device, mapping MBIM DSS session A to VLAN ID (256 + A) for all values +of A. + +The device maximum A is given in the MBIM_DEVICE_SERVICES_INFO +structure described in section 10.5.29 of [1]. + +The DSS VLAN subdevices are used as a practical interface between the +shared MBIM data channel and a MBIM DSS aware userspace application. +It is not intended to be presented as-is to an end user. The +assumption is that a userspace application initiating a DSS session +also takes care of the necessary framing of the DSS data, presenting +the stream to the end user in an appropriate way for the stream type. + +The network device ABI requires a dummy ethernet header for every DSS +data frame being transported. The contents of this header is +arbitrary, with the following exceptions: + + - TX frames using an IP protocol (0x0800 or 0x86dd) will be dropped + - RX frames will have the protocol field set to ETH_P_802_3 (but will + not be properly formatted 802.3 frames) + - RX frames will have the destination address set to the hardware + address of the master device + +The DSS supporting userspace management application is responsible for +adding the dummy ethernet header on TX and stripping it on RX. + +This is a simple example using tools commonly available, exporting +DssSessionId 5 as a pty character device pointed to by a /dev/nmea +symlink:: + + ip link add link wwan0 name wwan0.dss5 type vlan id 261 + ip link set dev wwan0.dss5 up + socat INTERFACE:wwan0.dss5,type=2 PTY:,echo=0,link=/dev/nmea + +This is only an example, most suitable for testing out a DSS +service. Userspace applications supporting specific MBIM DSS services +are expected to use the tools and programming interfaces required by +that service. + +Note that adding VLAN links for DSS sessions is entirely optional. A +management application may instead choose to bind a packet socket +directly to the master network device, using the received VLAN tags to +map frames to the correct DSS session and adding 18 byte VLAN ethernet +headers with the appropriate tag on TX. In this case using a socket +filter is recommended, matching only the DSS VLAN subset. This avoid +unnecessary copying of unrelated IP session data to userspace. For +example:: + + static struct sock_filter dssfilter[] = { + /* use special negative offsets to get VLAN tag */ + BPF_STMT(BPF_LD|BPF_B|BPF_ABS, SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT), + BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 1, 0, 6), /* true */ + + /* verify DSS VLAN range */ + BPF_STMT(BPF_LD|BPF_H|BPF_ABS, SKF_AD_OFF + SKF_AD_VLAN_TAG), + BPF_JUMP(BPF_JMP|BPF_JGE|BPF_K, 256, 0, 4), /* 256 is first DSS VLAN */ + BPF_JUMP(BPF_JMP|BPF_JGE|BPF_K, 512, 3, 0), /* 511 is last DSS VLAN */ + + /* verify ethertype */ + BPF_STMT(BPF_LD|BPF_H|BPF_ABS, 2 * ETH_ALEN), + BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, ETH_P_802_3, 0, 1), + + BPF_STMT(BPF_RET|BPF_K, (u_int)-1), /* accept */ + BPF_STMT(BPF_RET|BPF_K, 0), /* ignore */ + }; + + + +Tagged IP session 0 VLAN +------------------------ +As described above, MBIM IP session 0 is treated as special by the +driver. It is initially mapped to untagged frames on the wwanY +network device. + +This mapping implies a few restrictions on multiplexed IPS and DSS +sessions, which may not always be practical: + + - no IPS or DSS session can use a frame size greater than the MTU on + IP session 0 + - no IPS or DSS session can be in the up state unless the network + device representing IP session 0 also is up + +These problems can be avoided by optionally making the driver map IP +session 0 to a VLAN subdevice, similar to all other IP sessions. This +behaviour is triggered by adding a VLAN link for the magic VLAN ID +4094. The driver will then immediately start mapping MBIM IP session +0 to this VLAN, and will drop untagged frames on the master wwanY +device. + +Tip: It might be less confusing to the end user to name this VLAN +subdevice after the MBIM SessionID instead of the VLAN ID. For +example:: + + ip link add link wwan0 name wwan0.0 type vlan id 4094 + + +VLAN mapping +------------ + +Summarizing the cdc_mbim driver mapping described above, we have this +relationship between VLAN tags on the wwanY network device and MBIM +sessions on the shared USB data channel:: + + VLAN ID MBIM type MBIM SessionID Notes + --------------------------------------------------------- + untagged IPS 0 a) + 1 - 255 IPS 1 - 255 <VLANID> + 256 - 511 DSS 0 - 255 <VLANID - 256> + 512 - 4093 b) + 4094 IPS 0 c) + + a) if no VLAN ID 4094 link exists, else dropped + b) unsupported VLAN range, unconditionally dropped + c) if a VLAN ID 4094 link exists, else dropped + + + + +References +========== + + 1) USB Implementers Forum, Inc. - "Universal Serial Bus + Communications Class Subclass Specification for Mobile Broadband + Interface Model", Revision 1.0 (Errata 1), May 1, 2013 + + - http://www.usb.org/developers/docs/devclass_docs/ + + 2) USB Implementers Forum, Inc. - "Universal Serial Bus + Communications Class Subclass Specifications for Network Control + Model Devices", Revision 1.0 (Errata 1), November 24, 2010 + + - http://www.usb.org/developers/docs/devclass_docs/ + + 3) libmbim - "a glib-based library for talking to WWAN modems and + devices which speak the Mobile Interface Broadband Model (MBIM) + protocol" + + - http://www.freedesktop.org/wiki/Software/libmbim/ + + 4) ModemManager - "a DBus-activated daemon which controls mobile + broadband (2G/3G/4G) devices and connections" + + - http://www.freedesktop.org/wiki/Software/ModemManager/ + + 5) "MBIM (Mobile Broadband Interface Model) Registry" + + - http://compliance.usb.org/mbim/ + + 6) "/sys/kernel/debug/usb/devices output format" + + - Documentation/driver-api/usb/usb.rst + + 7) "/sys/bus/usb/devices/.../descriptors" + + - Documentation/ABI/stable/sysfs-bus-usb diff --git a/Documentation/networking/checksum-offloads.rst b/Documentation/networking/checksum-offloads.rst new file mode 100644 index 0000000000..69b23cf687 --- /dev/null +++ b/Documentation/networking/checksum-offloads.rst @@ -0,0 +1,143 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================= +Checksum Offloads +================= + + +Introduction +============ + +This document describes a set of techniques in the Linux networking stack to +take advantage of checksum offload capabilities of various NICs. + +The following technologies are described: + +* TX Checksum Offload +* LCO: Local Checksum Offload +* RCO: Remote Checksum Offload + +Things that should be documented here but aren't yet: + +* RX Checksum Offload +* CHECKSUM_UNNECESSARY conversion + + +TX Checksum Offload +=================== + +The interface for offloading a transmit checksum to a device is explained in +detail in comments near the top of include/linux/skbuff.h. + +In brief, it allows to request the device fill in a single ones-complement +checksum defined by the sk_buff fields skb->csum_start and skb->csum_offset. +The device should compute the 16-bit ones-complement checksum (i.e. the +'IP-style' checksum) from csum_start to the end of the packet, and fill in the +result at (csum_start + csum_offset). + +Because csum_offset cannot be negative, this ensures that the previous value of +the checksum field is included in the checksum computation, thus it can be used +to supply any needed corrections to the checksum (such as the sum of the +pseudo-header for UDP or TCP). + +This interface only allows a single checksum to be offloaded. Where +encapsulation is used, the packet may have multiple checksum fields in +different header layers, and the rest will have to be handled by another +mechanism such as LCO or RCO. + +CRC32c can also be offloaded using this interface, by means of filling +skb->csum_start and skb->csum_offset as described above, and setting +skb->csum_not_inet: see skbuff.h comment (section 'D') for more details. + +No offloading of the IP header checksum is performed; it is always done in +software. This is OK because when we build the IP header, we obviously have it +in cache, so summing it isn't expensive. It's also rather short. + +The requirements for GSO are more complicated, because when segmenting an +encapsulated packet both the inner and outer checksums may need to be edited or +recomputed for each resulting segment. See the skbuff.h comment (section 'E') +for more details. + +A driver declares its offload capabilities in netdev->hw_features; see +Documentation/networking/netdev-features.rst for more. Note that a device +which only advertises NETIF_F_IP[V6]_CSUM must still obey the csum_start and +csum_offset given in the SKB; if it tries to deduce these itself in hardware +(as some NICs do) the driver should check that the values in the SKB match +those which the hardware will deduce, and if not, fall back to checksumming in +software instead (with skb_csum_hwoffload_help() or one of the +skb_checksum_help() / skb_crc32c_csum_help functions, as mentioned in +include/linux/skbuff.h). + +The stack should, for the most part, assume that checksum offload is supported +by the underlying device. The only place that should check is +validate_xmit_skb(), and the functions it calls directly or indirectly. That +function compares the offload features requested by the SKB (which may include +other offloads besides TX Checksum Offload) and, if they are not supported or +enabled on the device (determined by netdev->features), performs the +corresponding offload in software. In the case of TX Checksum Offload, that +means calling skb_csum_hwoffload_help(skb, features). + + +LCO: Local Checksum Offload +=========================== + +LCO is a technique for efficiently computing the outer checksum of an +encapsulated datagram when the inner checksum is due to be offloaded. + +The ones-complement sum of a correctly checksummed TCP or UDP packet is equal +to the complement of the sum of the pseudo header, because everything else gets +'cancelled out' by the checksum field. This is because the sum was +complemented before being written to the checksum field. + +More generally, this holds in any case where the 'IP-style' ones complement +checksum is used, and thus any checksum that TX Checksum Offload supports. + +That is, if we have set up TX Checksum Offload with a start/offset pair, we +know that after the device has filled in that checksum, the ones complement sum +from csum_start to the end of the packet will be equal to the complement of +whatever value we put in the checksum field beforehand. This allows us to +compute the outer checksum without looking at the payload: we simply stop +summing when we get to csum_start, then add the complement of the 16-bit word +at (csum_start + csum_offset). + +Then, when the true inner checksum is filled in (either by hardware or by +skb_checksum_help()), the outer checksum will become correct by virtue of the +arithmetic. + +LCO is performed by the stack when constructing an outer UDP header for an +encapsulation such as VXLAN or GENEVE, in udp_set_csum(). Similarly for the +IPv6 equivalents, in udp6_set_csum(). + +It is also performed when constructing an IPv4 GRE header, in +net/ipv4/ip_gre.c:build_header(). It is *not* currently performed when +constructing an IPv6 GRE header; the GRE checksum is computed over the whole +packet in net/ipv6/ip6_gre.c:ip6gre_xmit2(), but it should be possible to use +LCO here as IPv6 GRE still uses an IP-style checksum. + +All of the LCO implementations use a helper function lco_csum(), in +include/linux/skbuff.h. + +LCO can safely be used for nested encapsulations; in this case, the outer +encapsulation layer will sum over both its own header and the 'middle' header. +This does mean that the 'middle' header will get summed multiple times, but +there doesn't seem to be a way to avoid that without incurring bigger costs +(e.g. in SKB bloat). + + +RCO: Remote Checksum Offload +============================ + +RCO is a technique for eliding the inner checksum of an encapsulated datagram, +allowing the outer checksum to be offloaded. It does, however, involve a +change to the encapsulation protocols, which the receiver must also support. +For this reason, it is disabled by default. + +RCO is detailed in the following Internet-Drafts: + +* https://tools.ietf.org/html/draft-herbert-remotecsumoffload-00 +* https://tools.ietf.org/html/draft-herbert-vxlan-rco-00 + +In Linux, RCO is implemented individually in each encapsulation protocol, and +most tunnel types have flags controlling its use. For instance, VXLAN has the +flag VXLAN_F_REMCSUM_TX (per struct vxlan_rdst) to indicate that RCO should be +used when transmitting to a given remote destination. diff --git a/Documentation/networking/dccp.rst b/Documentation/networking/dccp.rst new file mode 100644 index 0000000000..91e5c33ba3 --- /dev/null +++ b/Documentation/networking/dccp.rst @@ -0,0 +1,219 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============= +DCCP protocol +============= + + +.. Contents + - Introduction + - Missing features + - Socket options + - Sysctl variables + - IOCTLs + - Other tunables + - Notes + + +Introduction +============ +Datagram Congestion Control Protocol (DCCP) is an unreliable, connection +oriented protocol designed to solve issues present in UDP and TCP, particularly +for real-time and multimedia (streaming) traffic. +It divides into a base protocol (RFC 4340) and pluggable congestion control +modules called CCIDs. Like pluggable TCP congestion control, at least one CCID +needs to be enabled in order for the protocol to function properly. In the Linux +implementation, this is the TCP-like CCID2 (RFC 4341). Additional CCIDs, such as +the TCP-friendly CCID3 (RFC 4342), are optional. +For a brief introduction to CCIDs and suggestions for choosing a CCID to match +given applications, see section 10 of RFC 4340. + +It has a base protocol and pluggable congestion control IDs (CCIDs). + +DCCP is a Proposed Standard (RFC 2026), and the homepage for DCCP as a protocol +is at http://www.ietf.org/html.charters/dccp-charter.html + + +Missing features +================ +The Linux DCCP implementation does not currently support all the features that are +specified in RFCs 4340...42. + +The known bugs are at: + + http://www.linuxfoundation.org/collaborate/workgroups/networking/todo#DCCP + +For more up-to-date versions of the DCCP implementation, please consider using +the experimental DCCP test tree; instructions for checking this out are on: +http://www.linuxfoundation.org/collaborate/workgroups/networking/dccp_testing#Experimental_DCCP_source_tree + + +Socket options +============== +DCCP_SOCKOPT_QPOLICY_ID sets the dequeuing policy for outgoing packets. It takes +a policy ID as argument and can only be set before the connection (i.e. changes +during an established connection are not supported). Currently, two policies are +defined: the "simple" policy (DCCPQ_POLICY_SIMPLE), which does nothing special, +and a priority-based variant (DCCPQ_POLICY_PRIO). The latter allows to pass an +u32 priority value as ancillary data to sendmsg(), where higher numbers indicate +a higher packet priority (similar to SO_PRIORITY). This ancillary data needs to +be formatted using a cmsg(3) message header filled in as follows:: + + cmsg->cmsg_level = SOL_DCCP; + cmsg->cmsg_type = DCCP_SCM_PRIORITY; + cmsg->cmsg_len = CMSG_LEN(sizeof(uint32_t)); /* or CMSG_LEN(4) */ + +DCCP_SOCKOPT_QPOLICY_TXQLEN sets the maximum length of the output queue. A zero +value is always interpreted as unbounded queue length. If different from zero, +the interpretation of this parameter depends on the current dequeuing policy +(see above): the "simple" policy will enforce a fixed queue size by returning +EAGAIN, whereas the "prio" policy enforces a fixed queue length by dropping the +lowest-priority packet first. The default value for this parameter is +initialised from /proc/sys/net/dccp/default/tx_qlen. + +DCCP_SOCKOPT_SERVICE sets the service. The specification mandates use of +service codes (RFC 4340, sec. 8.1.2); if this socket option is not set, +the socket will fall back to 0 (which means that no meaningful service code +is present). On active sockets this is set before connect(); specifying more +than one code has no effect (all subsequent service codes are ignored). The +case is different for passive sockets, where multiple service codes (up to 32) +can be set before calling bind(). + +DCCP_SOCKOPT_GET_CUR_MPS is read-only and retrieves the current maximum packet +size (application payload size) in bytes, see RFC 4340, section 14. + +DCCP_SOCKOPT_AVAILABLE_CCIDS is also read-only and returns the list of CCIDs +supported by the endpoint. The option value is an array of type uint8_t whose +size is passed as option length. The minimum array size is 4 elements, the +value returned in the optlen argument always reflects the true number of +built-in CCIDs. + +DCCP_SOCKOPT_CCID is write-only and sets both the TX and RX CCIDs at the same +time, combining the operation of the next two socket options. This option is +preferable over the latter two, since often applications will use the same +type of CCID for both directions; and mixed use of CCIDs is not currently well +understood. This socket option takes as argument at least one uint8_t value, or +an array of uint8_t values, which must match available CCIDS (see above). CCIDs +must be registered on the socket before calling connect() or listen(). + +DCCP_SOCKOPT_TX_CCID is read/write. It returns the current CCID (if set) or sets +the preference list for the TX CCID, using the same format as DCCP_SOCKOPT_CCID. +Please note that the getsockopt argument type here is ``int``, not uint8_t. + +DCCP_SOCKOPT_RX_CCID is analogous to DCCP_SOCKOPT_TX_CCID, but for the RX CCID. + +DCCP_SOCKOPT_SERVER_TIMEWAIT enables the server (listening socket) to hold +timewait state when closing the connection (RFC 4340, 8.3). The usual case is +that the closing server sends a CloseReq, whereupon the client holds timewait +state. When this boolean socket option is on, the server sends a Close instead +and will enter TIMEWAIT. This option must be set after accept() returns. + +DCCP_SOCKOPT_SEND_CSCOV and DCCP_SOCKOPT_RECV_CSCOV are used for setting the +partial checksum coverage (RFC 4340, sec. 9.2). The default is that checksums +always cover the entire packet and that only fully covered application data is +accepted by the receiver. Hence, when using this feature on the sender, it must +be enabled at the receiver, too with suitable choice of CsCov. + +DCCP_SOCKOPT_SEND_CSCOV sets the sender checksum coverage. Values in the + range 0..15 are acceptable. The default setting is 0 (full coverage), + values between 1..15 indicate partial coverage. + +DCCP_SOCKOPT_RECV_CSCOV is for the receiver and has a different meaning: it + sets a threshold, where again values 0..15 are acceptable. The default + of 0 means that all packets with a partial coverage will be discarded. + Values in the range 1..15 indicate that packets with minimally such a + coverage value are also acceptable. The higher the number, the more + restrictive this setting (see [RFC 4340, sec. 9.2.1]). Partial coverage + settings are inherited to the child socket after accept(). + +The following two options apply to CCID 3 exclusively and are getsockopt()-only. +In either case, a TFRC info struct (defined in <linux/tfrc.h>) is returned. + +DCCP_SOCKOPT_CCID_RX_INFO + Returns a ``struct tfrc_rx_info`` in optval; the buffer for optval and + optlen must be set to at least sizeof(struct tfrc_rx_info). + +DCCP_SOCKOPT_CCID_TX_INFO + Returns a ``struct tfrc_tx_info`` in optval; the buffer for optval and + optlen must be set to at least sizeof(struct tfrc_tx_info). + +On unidirectional connections it is useful to close the unused half-connection +via shutdown (SHUT_WR or SHUT_RD): this will reduce per-packet processing costs. + + +Sysctl variables +================ +Several DCCP default parameters can be managed by the following sysctls +(sysctl net.dccp.default or /proc/sys/net/dccp/default): + +request_retries + The number of active connection initiation retries (the number of + Requests minus one) before timing out. In addition, it also governs + the behaviour of the other, passive side: this variable also sets + the number of times DCCP repeats sending a Response when the initial + handshake does not progress from RESPOND to OPEN (i.e. when no Ack + is received after the initial Request). This value should be greater + than 0, suggested is less than 10. Analogue of tcp_syn_retries. + +retries1 + How often a DCCP Response is retransmitted until the listening DCCP + side considers its connecting peer dead. Analogue of tcp_retries1. + +retries2 + The number of times a general DCCP packet is retransmitted. This has + importance for retransmitted acknowledgments and feature negotiation, + data packets are never retransmitted. Analogue of tcp_retries2. + +tx_ccid = 2 + Default CCID for the sender-receiver half-connection. Depending on the + choice of CCID, the Send Ack Vector feature is enabled automatically. + +rx_ccid = 2 + Default CCID for the receiver-sender half-connection; see tx_ccid. + +seq_window = 100 + The initial sequence window (sec. 7.5.2) of the sender. This influences + the local ackno validity and the remote seqno validity windows (7.5.1). + Values in the range Wmin = 32 (RFC 4340, 7.5.2) up to 2^32-1 can be set. + +tx_qlen = 5 + The size of the transmit buffer in packets. A value of 0 corresponds + to an unbounded transmit buffer. + +sync_ratelimit = 125 ms + The timeout between subsequent DCCP-Sync packets sent in response to + sequence-invalid packets on the same socket (RFC 4340, 7.5.4). The unit + of this parameter is milliseconds; a value of 0 disables rate-limiting. + + +IOCTLS +====== +FIONREAD + Works as in udp(7): returns in the ``int`` argument pointer the size of + the next pending datagram in bytes, or 0 when no datagram is pending. + +SIOCOUTQ + Returns the number of unsent data bytes in the socket send queue as ``int`` + into the buffer specified by the argument pointer. + +Other tunables +============== +Per-route rto_min support + CCID-2 supports the RTAX_RTO_MIN per-route setting for the minimum value + of the RTO timer. This setting can be modified via the 'rto_min' option + of iproute2; for example:: + + > ip route change 10.0.0.0/24 rto_min 250j dev wlan0 + > ip route add 10.0.0.254/32 rto_min 800j dev wlan0 + > ip route show dev wlan0 + + CCID-3 also supports the rto_min setting: it is used to define the lower + bound for the expiry of the nofeedback timer. This can be useful on LANs + with very low RTTs (e.g., loopback, Gbit ethernet). + + +Notes +===== +DCCP does not travel through NAT successfully at present on many boxes. This is +because the checksum covers the pseudo-header as per TCP and UDP. Linux NAT +support for DCCP has been added. diff --git a/Documentation/networking/dctcp.rst b/Documentation/networking/dctcp.rst new file mode 100644 index 0000000000..4cc8bb2dad --- /dev/null +++ b/Documentation/networking/dctcp.rst @@ -0,0 +1,52 @@ +.. SPDX-License-Identifier: GPL-2.0 + +====================== +DCTCP (DataCenter TCP) +====================== + +DCTCP is an enhancement to the TCP congestion control algorithm for data +center networks and leverages Explicit Congestion Notification (ECN) in +the data center network to provide multi-bit feedback to the end hosts. + +To enable it on end hosts:: + + sysctl -w net.ipv4.tcp_congestion_control=dctcp + sysctl -w net.ipv4.tcp_ecn_fallback=0 (optional) + +All switches in the data center network running DCTCP must support ECN +marking and be configured for marking when reaching defined switch buffer +thresholds. The default ECN marking threshold heuristic for DCTCP on +switches is 20 packets (30KB) at 1Gbps, and 65 packets (~100KB) at 10Gbps, +but might need further careful tweaking. + +For more details, see below documents: + +Paper: + +The algorithm is further described in detail in the following two +SIGCOMM/SIGMETRICS papers: + + i) Mohammad Alizadeh, Albert Greenberg, David A. Maltz, Jitendra Padhye, + Parveen Patel, Balaji Prabhakar, Sudipta Sengupta, and Murari Sridharan: + + "Data Center TCP (DCTCP)", Data Center Networks session" + + Proc. ACM SIGCOMM, New Delhi, 2010. + + http://simula.stanford.edu/~alizade/Site/DCTCP_files/dctcp-final.pdf + http://www.sigcomm.org/ccr/papers/2010/October/1851275.1851192 + +ii) Mohammad Alizadeh, Adel Javanmard, and Balaji Prabhakar: + + "Analysis of DCTCP: Stability, Convergence, and Fairness" + Proc. ACM SIGMETRICS, San Jose, 2011. + + http://simula.stanford.edu/~alizade/Site/DCTCP_files/dctcp_analysis-full.pdf + +IETF informational draft: + + http://tools.ietf.org/html/draft-bensley-tcpm-dctcp-00 + +DCTCP site: + + http://simula.stanford.edu/~alizade/Site/DCTCP.html diff --git a/Documentation/networking/device_drivers/appletalk/cops.rst b/Documentation/networking/device_drivers/appletalk/cops.rst new file mode 100644 index 0000000000..964ba80599 --- /dev/null +++ b/Documentation/networking/device_drivers/appletalk/cops.rst @@ -0,0 +1,80 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======================================== +The COPS LocalTalk Linux driver (cops.c) +======================================== + +By Jay Schulist <jschlst@samba.org> + +This driver has two modes and they are: Dayna mode and Tangent mode. +Each mode corresponds with the type of card. It has been found +that there are 2 main types of cards and all other cards are +the same and just have different names or only have minor differences +such as more IO ports. As this driver is tested it will +become more clear exactly what cards are supported. + +Right now these cards are known to work with the COPS driver. The +LT-200 cards work in a somewhat more limited capacity than the +DL200 cards, which work very well and are in use by many people. + +TANGENT driver mode: + - Tangent ATB-II, Novell NL-1000, Daystar Digital LT-200 + +DAYNA driver mode: + - Dayna DL2000/DaynaTalk PC (Half Length), COPS LT-95, + - Farallon PhoneNET PC III, Farallon PhoneNET PC II + +Other cards possibly supported mode unknown though: + - Dayna DL2000 (Full length) + +The COPS driver defaults to using Dayna mode. To change the driver's +mode if you built a driver with dual support use board_type=1 or +board_type=2 for Dayna or Tangent with insmod. + +Operation/loading of the driver +=============================== + +Use modprobe like this: /sbin/modprobe cops.o (IO #) (IRQ #) +If you do not specify any options the driver will try and use the IO = 0x240, +IRQ = 5. As of right now I would only use IRQ 5 for the card, if autoprobing. + +To load multiple COPS driver Localtalk cards you can do one of the following:: + + insmod cops io=0x240 irq=5 + insmod -o cops2 cops io=0x260 irq=3 + +Or in lilo.conf put something like this:: + + append="ether=5,0x240,lt0 ether=3,0x260,lt1" + +Then bring up the interface with ifconfig. It will look something like this:: + + lt0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-F7-00-00-00-00-00-00-00-00 + inet addr:192.168.1.2 Bcast:192.168.1.255 Mask:255.255.255.0 + UP BROADCAST RUNNING NOARP MULTICAST MTU:600 Metric:1 + RX packets:0 errors:0 dropped:0 overruns:0 frame:0 + TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 coll:0 + +Netatalk Configuration +====================== + +You will need to configure atalkd with something like the following to make +it work with the cops.c driver. + +* For single LTalk card use:: + + dummy -seed -phase 2 -net 2000 -addr 2000.10 -zone "1033" + lt0 -seed -phase 1 -net 1000 -addr 1000.50 -zone "1033" + +* For multiple cards, Ethernet and LocalTalk:: + + eth0 -seed -phase 2 -net 3000 -addr 3000.20 -zone "1033" + lt0 -seed -phase 1 -net 1000 -addr 1000.50 -zone "1033" + +* For multiple LocalTalk cards, and an Ethernet card. + +* Order seems to matter here, Ethernet last:: + + lt0 -seed -phase 1 -net 1000 -addr 1000.10 -zone "LocalTalk1" + lt1 -seed -phase 1 -net 2000 -addr 2000.20 -zone "LocalTalk2" + eth0 -seed -phase 2 -net 3000 -addr 3000.30 -zone "EtherTalk" diff --git a/Documentation/networking/device_drivers/appletalk/index.rst b/Documentation/networking/device_drivers/appletalk/index.rst new file mode 100644 index 0000000000..c196baeb08 --- /dev/null +++ b/Documentation/networking/device_drivers/appletalk/index.rst @@ -0,0 +1,18 @@ +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) + +AppleTalk Device Drivers +======================== + +Contents: + +.. toctree:: + :maxdepth: 2 + + cops + +.. only:: subproject and html + + Indices + ======= + + * :ref:`genindex` diff --git a/Documentation/networking/device_drivers/atm/cxacru-cf.py b/Documentation/networking/device_drivers/atm/cxacru-cf.py new file mode 100644 index 0000000000..b41d298398 --- /dev/null +++ b/Documentation/networking/device_drivers/atm/cxacru-cf.py @@ -0,0 +1,48 @@ +#!/usr/bin/env python +# Copyright 2009 Simon Arlott +# +# This program is free software; you can redistribute it and/or modify it +# under the terms of the GNU General Public License as published by the Free +# Software Foundation; either version 2 of the License, or (at your option) +# any later version. +# +# This program is distributed in the hope that it will be useful, but WITHOUT +# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or +# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for +# more details. +# +# You should have received a copy of the GNU General Public License along with +# this program; if not, write to the Free Software Foundation, Inc., 59 +# Temple Place - Suite 330, Boston, MA 02111-1307, USA. +# +# Usage: cxacru-cf.py < cxacru-cf.bin +# Output: values string suitable for the sysfs adsl_config attribute +# +# Warning: cxacru-cf.bin with MD5 hash cdbac2689969d5ed5d4850f117702110 +# contains mis-aligned values which will stop the modem from being able +# to make a connection. If the first and last two bytes are removed then +# the values become valid, but the modulation will be forced to ANSI +# T1.413 only which may not be appropriate. +# +# The original binary format is a packed list of le32 values. + +import sys +import struct + +i = 0 +while True: + buf = sys.stdin.read(4) + + if len(buf) == 0: + break + elif len(buf) != 4: + sys.stdout.write("\n") + sys.stderr.write("Error: read {0} not 4 bytes\n".format(len(buf))) + sys.exit(1) + + if i > 0: + sys.stdout.write(" ") + sys.stdout.write("{0:x}={1}".format(i, struct.unpack("<I", buf)[0])) + i += 1 + +sys.stdout.write("\n") diff --git a/Documentation/networking/device_drivers/atm/cxacru.rst b/Documentation/networking/device_drivers/atm/cxacru.rst new file mode 100644 index 0000000000..6088af2ffe --- /dev/null +++ b/Documentation/networking/device_drivers/atm/cxacru.rst @@ -0,0 +1,120 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======================== +ATM cxacru device driver +======================== + +Firmware is required for this device: http://accessrunner.sourceforge.net/ + +While it is capable of managing/maintaining the ADSL connection without the +module loaded, the device will sometimes stop responding after unloading the +driver and it is necessary to unplug/remove power to the device to fix this. + +Note: support for cxacru-cf.bin has been removed. It was not loaded correctly +so it had no effect on the device configuration. Fixing it could have stopped +existing devices working when an invalid configuration is supplied. + +There is a script cxacru-cf.py to convert an existing file to the sysfs form. + +Detected devices will appear as ATM devices named "cxacru". In /sys/class/atm/ +these are directories named cxacruN where N is the device number. A symlink +named device points to the USB interface device's directory which contains +several sysfs attribute files for retrieving device statistics: + +* adsl_controller_version + +* adsl_headend +* adsl_headend_environment + + - Information about the remote headend. + +* adsl_config + + - Configuration writing interface. + - Write parameters in hexadecimal format <index>=<value>, + separated by whitespace, e.g.: + + "1=0 a=5" + + - Up to 7 parameters at a time will be sent and the modem will restart + the ADSL connection when any value is set. These are logged for future + reference. + +* downstream_attenuation (dB) +* downstream_bits_per_frame +* downstream_rate (kbps) +* downstream_snr_margin (dB) + + - Downstream stats. + +* upstream_attenuation (dB) +* upstream_bits_per_frame +* upstream_rate (kbps) +* upstream_snr_margin (dB) +* transmitter_power (dBm/Hz) + + - Upstream stats. + +* downstream_crc_errors +* downstream_fec_errors +* downstream_hec_errors +* upstream_crc_errors +* upstream_fec_errors +* upstream_hec_errors + + - Error counts. + +* line_startable + + - Indicates that ADSL support on the device + is/can be enabled, see adsl_start. + +* line_status + + - "initialising" + - "down" + - "attempting to activate" + - "training" + - "channel analysis" + - "exchange" + - "waiting" + - "up" + + Changes between "down" and "attempting to activate" + if there is no signal. + +* link_status + + - "not connected" + - "connected" + - "lost" + +* mac_address + +* modulation + + - "" (when not connected) + - "ANSI T1.413" + - "ITU-T G.992.1 (G.DMT)" + - "ITU-T G.992.2 (G.LITE)" + +* startup_attempts + + - Count of total attempts to initialise ADSL. + +To enable/disable ADSL, the following can be written to the adsl_state file: + + - "start" + - "stop + - "restart" (stops, waits 1.5s, then starts) + - "poll" (used to resume status polling if it was disabled due to failure) + +Changes in adsl/line state are reported via kernel log messages:: + + [4942145.150704] ATM dev 0: ADSL state: running + [4942243.663766] ATM dev 0: ADSL line: down + [4942249.665075] ATM dev 0: ADSL line: attempting to activate + [4942253.654954] ATM dev 0: ADSL line: training + [4942255.666387] ATM dev 0: ADSL line: channel analysis + [4942259.656262] ATM dev 0: ADSL line: exchange + [2635357.696901] ATM dev 0: ADSL line: up (8128 kb/s down | 832 kb/s up) diff --git a/Documentation/networking/device_drivers/atm/fore200e.rst b/Documentation/networking/device_drivers/atm/fore200e.rst new file mode 100644 index 0000000000..55df9ec09a --- /dev/null +++ b/Documentation/networking/device_drivers/atm/fore200e.rst @@ -0,0 +1,66 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================================= +FORE Systems PCA-200E/SBA-200E ATM NIC driver +============================================= + +This driver adds support for the FORE Systems 200E-series ATM adapters +to the Linux operating system. It is based on the earlier PCA-200E driver +written by Uwe Dannowski. + +The driver simultaneously supports PCA-200E and SBA-200E adapters on +i386, alpha (untested), powerpc, sparc and sparc64 archs. + +The intent is to enable the use of different models of FORE adapters at the +same time, by hosts that have several bus interfaces (such as PCI+SBUS, +or PCI+EISA). + +Only PCI and SBUS devices are currently supported by the driver, but support +for other bus interfaces such as EISA should not be too hard to add. + + +Firmware Copyright Notice +------------------------- + +Please read the fore200e_firmware_copyright file present +in the linux/drivers/atm directory for details and restrictions. + + +Firmware Updates +---------------- + +The FORE Systems 200E-series driver is shipped with firmware data being +uploaded to the ATM adapters at system boot time or at module loading time. +The supplied firmware images should work with all adapters. + +However, if you encounter problems (the firmware doesn't start or the driver +is unable to read the PROM data), you may consider trying another firmware +version. Alternative binary firmware images can be found somewhere on the +ForeThought CD-ROM supplied with your adapter by FORE Systems. + +You can also get the latest firmware images from FORE Systems at +https://en.wikipedia.org/wiki/FORE_Systems. Register TACTics Online and go to +the 'software updates' pages. The firmware binaries are part of +the various ForeThought software distributions. + +Notice that different versions of the PCA-200E firmware exist, depending +on the endianness of the host architecture. The driver is shipped with +both little and big endian PCA firmware images. + +Name and location of the new firmware images can be set at kernel +configuration time: + +1. Copy the new firmware binary files (with .bin, .bin1 or .bin2 suffix) + to some directory, such as linux/drivers/atm. + +2. Reconfigure your kernel to set the new firmware name and location. + Expected pathnames are absolute or relative to the drivers/atm directory. + +3. Rebuild and re-install your kernel or your module. + + +Feedback +-------- + +Feedback is welcome. Please send success stories/bug reports/ +patches/improvement/comments/flames to <lizzi@cnam.fr>. diff --git a/Documentation/networking/device_drivers/atm/index.rst b/Documentation/networking/device_drivers/atm/index.rst new file mode 100644 index 0000000000..7b593f031a --- /dev/null +++ b/Documentation/networking/device_drivers/atm/index.rst @@ -0,0 +1,20 @@ +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) + +Asynchronous Transfer Mode (ATM) Device Drivers +=============================================== + +Contents: + +.. toctree:: + :maxdepth: 2 + + cxacru + fore200e + iphase + +.. only:: subproject and html + + Indices + ======= + + * :ref:`genindex` diff --git a/Documentation/networking/device_drivers/atm/iphase.rst b/Documentation/networking/device_drivers/atm/iphase.rst new file mode 100644 index 0000000000..388c7101e2 --- /dev/null +++ b/Documentation/networking/device_drivers/atm/iphase.rst @@ -0,0 +1,193 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================================== +ATM (i)Chip IA Linux Driver Source +================================== + + READ ME FIRST + +-------------------------------------------------------------------------------- + + Read This Before You Begin! + +-------------------------------------------------------------------------------- + +Description +=========== + +This is the README file for the Interphase PCI ATM (i)Chip IA Linux driver +source release. + +The features and limitations of this driver are as follows: + + - A single VPI (VPI value of 0) is supported. + - Supports 4K VCs for the server board (with 512K control memory) and 1K + VCs for the client board (with 128K control memory). + - UBR, ABR and CBR service categories are supported. + - Only AAL5 is supported. + - Supports setting of PCR on the VCs. + - Multiple adapters in a system are supported. + - All variants of Interphase ATM PCI (i)Chip adapter cards are supported, + including x575 (OC3, control memory 128K , 512K and packet memory 128K, + 512K and 1M), x525 (UTP25) and x531 (DS3 and E3). See + http://www.iphase.com/ + for details. + - Only x86 platforms are supported. + - SMP is supported. + + +Before You Start +================ + + +Installation +------------ + +1. Installing the adapters in the system + + To install the ATM adapters in the system, follow the steps below. + + a. Login as root. + b. Shut down the system and power off the system. + c. Install one or more ATM adapters in the system. + d. Connect each adapter to a port on an ATM switch. The green 'Link' + LED on the front panel of the adapter will be on if the adapter is + connected to the switch properly when the system is powered up. + e. Power on and boot the system. + +2. [ Removed ] + +3. Rebuild kernel with ABR support + + [ a. and b. removed ] + + c. Reconfigure the kernel, choose the Interphase ia driver through "make + menuconfig" or "make xconfig". + d. Rebuild the kernel, loadable modules and the atm tools. + e. Install the new built kernel and modules and reboot. + +4. Load the adapter hardware driver (ia driver) if it is built as a module + + a. Login as root. + b. Change directory to /lib/modules/<kernel-version>/atm. + c. Run "insmod suni.o;insmod iphase.o" + The yellow 'status' LED on the front panel of the adapter will blink + while the driver is loaded in the system. + d. To verify that the 'ia' driver is loaded successfully, run the + following command:: + + cat /proc/atm/devices + + If the driver is loaded successfully, the output of the command will + be similar to the following lines:: + + Itf Type ESI/"MAC"addr AAL(TX,err,RX,err,drop) ... + 0 ia xxxxxxxxx 0 ( 0 0 0 0 0 ) 5 ( 0 0 0 0 0 ) + + You can also check the system log file /var/log/messages for messages + related to the ATM driver. + +5. Ia Driver Configuration + +5.1 Configuration of adapter buffers + The (i)Chip boards have 3 different packet RAM size variants: 128K, 512K and + 1M. The RAM size decides the number of buffers and buffer size. The default + size and number of buffers are set as following: + + ========= ======= ====== ====== ====== ====== ====== + Total Rx RAM Tx RAM Rx Buf Tx Buf Rx buf Tx buf + RAM size size size size size cnt cnt + ========= ======= ====== ====== ====== ====== ====== + 128K 64K 64K 10K 10K 6 6 + 512K 256K 256K 10K 10K 25 25 + 1M 512K 512K 10K 10K 51 51 + ========= ======= ====== ====== ====== ====== ====== + + These setting should work well in most environments, but can be + changed by typing the following command:: + + insmod <IA_DIR>/ia.o IA_RX_BUF=<RX_CNT> IA_RX_BUF_SZ=<RX_SIZE> \ + IA_TX_BUF=<TX_CNT> IA_TX_BUF_SZ=<TX_SIZE> + + Where: + + - RX_CNT = number of receive buffers in the range (1-128) + - RX_SIZE = size of receive buffers in the range (48-64K) + - TX_CNT = number of transmit buffers in the range (1-128) + - TX_SIZE = size of transmit buffers in the range (48-64K) + + 1. Transmit and receive buffer size must be a multiple of 4. + 2. Care should be taken so that the memory required for the + transmit and receive buffers is less than or equal to the + total adapter packet memory. + +5.2 Turn on ia debug trace + + When the ia driver is built with the CONFIG_ATM_IA_DEBUG flag, the driver + can provide more debug trace if needed. There is a bit mask variable, + IADebugFlag, which controls the output of the traces. You can find the bit + map of the IADebugFlag in iphase.h. + The debug trace can be turn on through the insmod command line option, for + example, "insmod iphase.o IADebugFlag=0xffffffff" can turn on all the debug + traces together with loading the driver. + +6. Ia Driver Test Using ttcp_atm and PVC + + For the PVC setup, the test machines can either be connected back-to-back or + through a switch. If connected through the switch, the switch must be + configured for the PVC(s). + + a. For UBR test: + + At the test machine intended to receive data, type:: + + ttcp_atm -r -a -s 0.100 + + At the other test machine, type:: + + ttcp_atm -t -a -s 0.100 -n 10000 + + Run "ttcp_atm -h" to display more options of the ttcp_atm tool. + b. For ABR test: + + It is the same as the UBR testing, but with an extra command option:: + + -Pabr:max_pcr=<xxx> + + where: + + xxx = the maximum peak cell rate, from 170 - 353207. + + This option must be set on both the machines. + + c. For CBR test: + + It is the same as the UBR testing, but with an extra command option:: + + -Pcbr:max_pcr=<xxx> + + where: + + xxx = the maximum peak cell rate, from 170 - 353207. + + This option may only be set on the transmit machine. + + +Outstanding Issues +================== + + + +Contact Information +------------------- + +:: + + Customer Support: + United States: Telephone: (214) 654-5555 + Fax: (214) 654-5500 + E-Mail: intouch@iphase.com + Europe: Telephone: 33 (0)1 41 15 44 00 + Fax: 33 (0)1 41 15 12 13 + World Wide Web: http://www.iphase.com + Anonymous FTP: ftp.iphase.com diff --git a/Documentation/networking/device_drivers/cable/index.rst b/Documentation/networking/device_drivers/cable/index.rst new file mode 100644 index 0000000000..cce3c43929 --- /dev/null +++ b/Documentation/networking/device_drivers/cable/index.rst @@ -0,0 +1,18 @@ +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) + +Cable Modem Device Drivers +========================== + +Contents: + +.. toctree:: + :maxdepth: 2 + + sb1000 + +.. only:: subproject and html + + Indices + ======= + + * :ref:`genindex` diff --git a/Documentation/networking/device_drivers/cable/sb1000.rst b/Documentation/networking/device_drivers/cable/sb1000.rst new file mode 100644 index 0000000000..c8582ca403 --- /dev/null +++ b/Documentation/networking/device_drivers/cable/sb1000.rst @@ -0,0 +1,222 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=================== +SB100 device driver +=================== + +sb1000 is a module network device driver for the General Instrument (also known +as NextLevel) SURFboard1000 internal cable modem board. This is an ISA card +which is used by a number of cable TV companies to provide cable modem access. +It's a one-way downstream-only cable modem, meaning that your upstream net link +is provided by your regular phone modem. + +This driver was written by Franco Venturi <fventuri@mediaone.net>. He deserves +a great deal of thanks for this wonderful piece of code! + +Needed tools +============ + +Support for this device is now a part of the standard Linux kernel. The +driver source code file is drivers/net/sb1000.c. In addition to this +you will need: + +1. The "cmconfig" program. This is a utility which supplements "ifconfig" + to configure the cable modem and network interface (usually called "cm0"); + +2. Several PPP scripts which live in /etc/ppp to make connecting via your + cable modem easy. + + These utilities can be obtained from: + + http://www.jacksonville.net/~fventuri/ + + in Franco's original source code distribution .tar.gz file. Support for + the sb1000 driver can be found at: + + - http://web.archive.org/web/%2E/http://home.adelphia.net/~siglercm/sb1000.html + - http://web.archive.org/web/%2E/http://linuxpower.cx/~cable/ + + along with these utilities. + +3. The standard isapnp tools. These are necessary to configure your SB1000 + card at boot time (or afterwards by hand) since it's a PnP card. + + If you don't have these installed as a standard part of your Linux + distribution, you can find them at: + + http://www.roestock.demon.co.uk/isapnptools/ + + or check your Linux distribution binary CD or their web site. For help with + isapnp, pnpdump, or /etc/isapnp.conf, go to: + + http://www.roestock.demon.co.uk/isapnptools/isapnpfaq.html + +Using the driver +================ + +To make the SB1000 card work, follow these steps: + +1. Run ``make config``, or ``make menuconfig``, or ``make xconfig``, whichever + you prefer, in the top kernel tree directory to set up your kernel + configuration. Make sure to say "Y" to "Prompt for development drivers" + and to say "M" to the sb1000 driver. Also say "Y" or "M" to all the standard + networking questions to get TCP/IP and PPP networking support. + +2. **BEFORE** you build the kernel, edit drivers/net/sb1000.c. Make sure + to redefine the value of READ_DATA_PORT to match the I/O address used + by isapnp to access your PnP cards. This is the value of READPORT in + /etc/isapnp.conf or given by the output of pnpdump. + +3. Build and install the kernel and modules as usual. + +4. Boot your new kernel following the usual procedures. + +5. Set up to configure the new SB1000 PnP card by capturing the output + of "pnpdump" to a file and editing this file to set the correct I/O ports, + IRQ, and DMA settings for all your PnP cards. Make sure none of the settings + conflict with one another. Then test this configuration by running the + "isapnp" command with your new config file as the input. Check for + errors and fix as necessary. (As an aside, I use I/O ports 0x110 and + 0x310 and IRQ 11 for my SB1000 card and these work well for me. YMMV.) + Then save the finished config file as /etc/isapnp.conf for proper + configuration on subsequent reboots. + +6. Download the original file sb1000-1.1.2.tar.gz from Franco's site or one of + the others referenced above. As root, unpack it into a temporary directory + and do a ``make cmconfig`` and then ``install -c cmconfig /usr/local/sbin``. + Don't do ``make install`` because it expects to find all the utilities built + and ready for installation, not just cmconfig. + +7. As root, copy all the files under the ppp/ subdirectory in Franco's + tar file into /etc/ppp, being careful not to overwrite any files that are + already in there. Then modify ppp@gi-on to set the correct login name, + phone number, and frequency for the cable modem. Also edit pap-secrets + to specify your login name and password and any site-specific information + you need. + +8. Be sure to modify /etc/ppp/firewall to use ipchains instead of + the older ipfwadm commands from the 2.0.x kernels. There's a neat utility to + convert ipfwadm commands to ipchains commands: + + http://users.dhp.com/~whisper/ipfwadm2ipchains/ + + You may also wish to modify the firewall script to implement a different + firewalling scheme. + +9. Start the PPP connection via the script /etc/ppp/ppp@gi-on. You must be + root to do this. It's better to use a utility like sudo to execute + frequently used commands like this with root permissions if possible. If you + connect successfully the cable modem interface will come up and you'll see a + driver message like this at the console:: + + cm0: sb1000 at (0x110,0x310), csn 1, S/N 0x2a0d16d8, IRQ 11. + sb1000.c:v1.1.2 6/01/98 (fventuri@mediaone.net) + + The "ifconfig" command should show two new interfaces, ppp0 and cm0. + + The command "cmconfig cm0" will give you information about the cable modem + interface. + +10. Try pinging a site via ``ping -c 5 www.yahoo.com``, for example. You should + see packets received. + +11. If you can't get site names (like www.yahoo.com) to resolve into + IP addresses (like 204.71.200.67), be sure your /etc/resolv.conf file + has no syntax errors and has the right nameserver IP addresses in it. + If this doesn't help, try something like ``ping -c 5 204.71.200.67`` to + see if the networking is running but the DNS resolution is where the + problem lies. + +12. If you still have problems, go to the support web sites mentioned above + and read the information and documentation there. + +Common problems +=============== + +1. Packets go out on the ppp0 interface but don't come back on the cm0 + interface. It looks like I'm connected but I can't even ping any + numerical IP addresses. (This happens predominantly on Debian systems due + to a default boot-time configuration script.) + +Solution + As root ``echo 0 > /proc/sys/net/ipv4/conf/cm0/rp_filter`` so it + can share the same IP address as the ppp0 interface. Note that this + command should probably be added to the /etc/ppp/cablemodem script + *right*between* the "/sbin/ifconfig" and "/sbin/cmconfig" commands. + You may need to do this to /proc/sys/net/ipv4/conf/ppp0/rp_filter as well. + If you do this to /proc/sys/net/ipv4/conf/default/rp_filter on each reboot + (in rc.local or some such) then any interfaces can share the same IP + addresses. + +2. I get "unresolved symbol" error messages on executing ``insmod sb1000.o``. + +Solution + You probably have a non-matching kernel source tree and + /usr/include/linux and /usr/include/asm header files. Make sure you + install the correct versions of the header files in these two directories. + Then rebuild and reinstall the kernel. + +3. When isapnp runs it reports an error, and my SB1000 card isn't working. + +Solution + There's a problem with later versions of isapnp using the "(CHECK)" + option in the lines that allocate the two I/O addresses for the SB1000 card. + This first popped up on RH 6.0. Delete "(CHECK)" for the SB1000 I/O addresses. + Make sure they don't conflict with any other pieces of hardware first! Then + rerun isapnp and go from there. + +4. I can't execute the /etc/ppp/ppp@gi-on file. + +Solution + As root do ``chmod ug+x /etc/ppp/ppp@gi-on``. + +5. The firewall script isn't working (with 2.2.x and higher kernels). + +Solution + Use the ipfwadm2ipchains script referenced above to convert the + /etc/ppp/firewall script from the deprecated ipfwadm commands to ipchains. + +6. I'm getting *tons* of firewall deny messages in the /var/kern.log, + /var/messages, and/or /var/syslog files, and they're filling up my /var + partition!!! + +Solution + First, tell your ISP that you're receiving DoS (Denial of Service) + and/or portscanning (UDP connection attempts) attacks! Look over the deny + messages to figure out what the attack is and where it's coming from. Next, + edit /etc/ppp/cablemodem and make sure the ",nobroadcast" option is turned on + to the "cmconfig" command (uncomment that line). If you're not receiving these + denied packets on your broadcast interface (IP address xxx.yyy.zzz.255 + typically), then someone is attacking your machine in particular. Be careful + out there.... + +7. Everything seems to work fine but my computer locks up after a while + (and typically during a lengthy download through the cable modem)! + +Solution + You may need to add a short delay in the driver to 'slow down' the + SURFboard because your PC might not be able to keep up with the transfer rate + of the SB1000. To do this, it's probably best to download Franco's + sb1000-1.1.2.tar.gz archive and build and install sb1000.o manually. You'll + want to edit the 'Makefile' and look for the 'SB1000_DELAY' + define. Uncomment those 'CFLAGS' lines (and comment out the default ones) + and try setting the delay to something like 60 microseconds with: + '-DSB1000_DELAY=60'. Then do ``make`` and as root ``make install`` and try + it out. If it still doesn't work or you like playing with the driver, you may + try other numbers. Remember though that the higher the delay, the slower the + driver (which slows down the rest of the PC too when it is actively + used). Thanks to Ed Daiga for this tip! + +Credits +======= + +This README came from Franco Venturi's original README file which is +still supplied with his driver .tar.gz archive. I and all other sb1000 users +owe Franco a tremendous "Thank you!" Additional thanks goes to Carl Patten +and Ralph Bonnell who are now managing the Linux SB1000 web site, and to +the SB1000 users who reported and helped debug the common problems listed +above. + + + Clemmitt Sigler + csigler@vt.edu diff --git a/Documentation/networking/device_drivers/can/can327.rst b/Documentation/networking/device_drivers/can/can327.rst new file mode 100644 index 0000000000..b87bfbe5d5 --- /dev/null +++ b/Documentation/networking/device_drivers/can/can327.rst @@ -0,0 +1,331 @@ +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause) + +can327: ELM327 driver for Linux SocketCAN +========================================== + +Authors +-------- + +Max Staudt <max@enpas.org> + + + +Motivation +----------- + +This driver aims to lower the initial cost for hackers interested in +working with CAN buses. + +CAN adapters are expensive, few, and far between. +ELM327 interfaces are cheap and plentiful. +Let's use ELM327s as CAN adapters. + + + +Introduction +------------- + +This driver is an effort to turn abundant ELM327 based OBD interfaces +into full fledged (as far as possible) CAN interfaces. + +Since the ELM327 was never meant to be a stand alone CAN controller, +the driver has to switch between its modes as quickly as possible in +order to fake full-duplex operation. + +As such, can327 is a best effort driver. However, this is more than +enough to implement simple request-response protocols (such as OBD II), +and to monitor broadcast messages on a bus (such as in a vehicle). + +Most ELM327s come as nondescript serial devices, attached via USB or +Bluetooth. The driver cannot recognize them by itself, and as such it +is up to the user to attach it in form of a TTY line discipline +(similar to PPP, SLIP, slcan, ...). + +This driver is meant for ELM327 versions 1.4b and up, see below for +known limitations in older controllers and clones. + + + +Data sheet +----------- + +The official data sheets can be found at ELM electronics' home page: + + https://www.elmelectronics.com/ + + + +How to attach the line discipline +---------------------------------- + +Every ELM327 chip is factory programmed to operate at a serial setting +of 38400 baud/s, 8 data bits, no parity, 1 stopbit. + +If you have kept this default configuration, the line discipline can +be attached on a command prompt as follows:: + + sudo ldattach \ + --debug \ + --speed 38400 \ + --eightbits \ + --noparity \ + --onestopbit \ + --iflag -ICRNL,INLCR,-IXOFF \ + 30 \ + /dev/ttyUSB0 + +To change the ELM327's serial settings, please refer to its data +sheet. This needs to be done before attaching the line discipline. + +Once the ldisc is attached, the CAN interface starts out unconfigured. +Set the speed before starting it:: + + # The interface needs to be down to change parameters + sudo ip link set can0 down + sudo ip link set can0 type can bitrate 500000 + sudo ip link set can0 up + +500000 bit/s is a common rate for OBD-II diagnostics. +If you're connecting straight to a car's OBD port, this is the speed +that most cars (but not all!) expect. + +After this, you can set out as usual with candump, cansniffer, etc. + + + +How to check the controller version +------------------------------------ + +Use a terminal program to attach to the controller. + +After issuing the "``AT WS``" command, the controller will respond with +its version:: + + >AT WS + + + ELM327 v1.4b + + > + +Note that clones may claim to be any version they like. +It is not indicative of their actual feature set. + + + + +Communication example +---------------------- + +This is a short and incomplete introduction on how to talk to an ELM327. +It is here to guide understanding of the controller's and the driver's +limitation (listed below) as well as manual testing. + + +The ELM327 has two modes: + +- Command mode +- Reception mode + +In command mode, it expects one command per line, terminated by CR. +By default, the prompt is a "``>``", after which a command can be +entered:: + + >ATE1 + OK + > + +The init script in the driver switches off several configuration options +that are only meaningful in the original OBD scenario the chip is meant +for, and are actually a hindrance for can327. + + +When a command is not recognized, such as by an older version of the +ELM327, a question mark is printed as a response instead of OK:: + + >ATUNKNOWN + ? + > + +At present, can327 does not evaluate this response. See the section +below on known limitations for details. + + +When a CAN frame is to be sent, the target address is configured, after +which the frame is sent as a command that consists of the data's hex +dump:: + + >ATSH123 + OK + >DEADBEEF12345678 + OK + > + +The above interaction sends the SFF frame "``DE AD BE EF 12 34 56 78``" +with (11 bit) CAN ID ``0x123``. +For this to function, the controller must be configured for SFF sending +mode (using "``AT PB``", see code or datasheet). + + +Once a frame has been sent and wait-for-reply mode is on (``ATR1``, +configured on ``listen-only=off``), or when the reply timeout expires +and the driver sets the controller into monitoring mode (``ATMA``), +the ELM327 will send one line for each received CAN frame, consisting +of CAN ID, DLC, and data:: + + 123 8 DEADBEEF12345678 + +For EFF (29 bit) CAN frames, the address format is slightly different, +which can327 uses to tell the two apart:: + + 12 34 56 78 8 DEADBEEF12345678 + +The ELM327 will receive both SFF and EFF frames - the current CAN +config (``ATPB``) does not matter. + + +If the ELM327's internal UART sending buffer runs full, it will abort +the monitoring mode, print "BUFFER FULL" and drop back into command +mode. Note that in this case, unlike with other error messages, the +error message may appear on the same line as the last (usually +incomplete) data frame:: + + 12 34 56 78 8 DEADBEEF123 BUFFER FULL + + + +Known limitations of the controller +------------------------------------ + +- Clone devices ("v1.5" and others) + + Sending RTR frames is not supported and will be dropped silently. + + Receiving RTR with DLC 8 will appear to be a regular frame with + the last received frame's DLC and payload. + + "``AT CSM``" (CAN Silent Monitoring, i.e. don't send CAN ACKs) is + not supported, and is hard coded to ON. Thus, frames are not ACKed + while listening: "``AT MA``" (Monitor All) will always be "silent". + However, immediately after sending a frame, the ELM327 will be in + "receive reply" mode, in which it *does* ACK any received frames. + Once the bus goes silent, or an error occurs (such as BUFFER FULL), + or the receive reply timeout runs out, the ELM327 will end reply + reception mode on its own and can327 will fall back to "``AT MA``" + in order to keep monitoring the bus. + + Other limitations may apply, depending on the clone and the quality + of its firmware. + + +- All versions + + No full duplex operation is supported. The driver will switch + between input/output mode as quickly as possible. + + The length of outgoing RTR frames cannot be set. In fact, some + clones (tested with one identifying as "``v1.5``") are unable to + send RTR frames at all. + + We don't have a way to get real-time notifications on CAN errors. + While there is a command (``AT CS``) to retrieve some basic stats, + we don't poll it as it would force us to interrupt reception mode. + + +- Versions prior to 1.4b + + These versions do not send CAN ACKs when in monitoring mode (AT MA). + However, they do send ACKs while waiting for a reply immediately + after sending a frame. The driver maximizes this time to make the + controller as useful as possible. + + Starting with version 1.4b, the ELM327 supports the "``AT CSM``" + command, and the "listen-only" CAN option will take effect. + + +- Versions prior to 1.4 + + These chips do not support the "``AT PB``" command, and thus cannot + change bitrate or SFF/EFF mode on-the-fly. This will have to be + programmed by the user before attaching the line discipline. See the + data sheet for details. + + +- Versions prior to 1.3 + + These chips cannot be used at all with can327. They do not support + the "``AT D1``" command, which is necessary to avoid parsing conflicts + on incoming data, as well as distinction of RTR frame lengths. + + Specifically, this allows for easy distinction of SFF and EFF + frames, and to check whether frames are complete. While it is possible + to deduce the type and length from the length of the line the ELM327 + sends us, this method fails when the ELM327's UART output buffer + overruns. It may abort sending in the middle of the line, which will + then be mistaken for something else. + + + +Known limitations of the driver +-------------------------------- + +- No 8/7 timing. + + ELM327 can only set CAN bitrates that are of the form 500000/n, where + n is an integer divisor. + However there is an exception: With a separate flag, it may set the + speed to be 8/7 of the speed indicated by the divisor. + This mode is not currently implemented. + +- No evaluation of command responses. + + The ELM327 will reply with OK when a command is understood, and with ? + when it is not. The driver does not currently check this, and simply + assumes that the chip understands every command. + The driver is built such that functionality degrades gracefully + nevertheless. See the section on known limitations of the controller. + +- No use of hardware CAN ID filtering + + An ELM327's UART sending buffer will easily overflow on heavy CAN bus + load, resulting in the "``BUFFER FULL``" message. Using the hardware + filters available through "``AT CF xxx``" and "``AT CM xxx``" would be + helpful here, however SocketCAN does not currently provide a facility + to make use of such hardware features. + + + +Rationale behind the chosen configuration +------------------------------------------ + +``AT E1`` + Echo on + + We need this to be able to get a prompt reliably. + +``AT S1`` + Spaces on + + We need this to distinguish 11/29 bit CAN addresses received. + + Note: + We can usually do this using the line length (odd/even), + but this fails if the line is not transmitted fully to + the host (BUFFER FULL). + +``AT D1`` + DLC on + + We need this to tell the "length" of RTR frames. + + + +A note on CAN bus termination +------------------------------ + +Your adapter may have resistors soldered in which are meant to terminate +the bus. This is correct when it is plugged into a OBD-II socket, but +not helpful when trying to tap into the middle of an existing CAN bus. + +If communications don't work with the adapter connected, check for the +termination resistors on its PCB and try removing them. diff --git a/Documentation/networking/device_drivers/can/ctu/ctucanfd-driver.rst b/Documentation/networking/device_drivers/can/ctu/ctucanfd-driver.rst new file mode 100644 index 0000000000..1661d13174 --- /dev/null +++ b/Documentation/networking/device_drivers/can/ctu/ctucanfd-driver.rst @@ -0,0 +1,638 @@ +.. SPDX-License-Identifier: GPL-2.0-or-later + +CTU CAN FD Driver +================= + +Author: Martin Jerabek <martin.jerabek01@gmail.com> + + +About CTU CAN FD IP Core +------------------------ + +`CTU CAN FD <https://gitlab.fel.cvut.cz/canbus/ctucanfd_ip_core>`_ +is an open source soft core written in VHDL. +It originated in 2015 as Ondrej Ille's project +at the `Department of Measurement <https://meas.fel.cvut.cz/>`_ +of `FEE <http://www.fel.cvut.cz/en/>`_ at `CTU <https://www.cvut.cz/en>`_. + +The SocketCAN driver for Xilinx Zynq SoC based MicroZed board +`Vivado integration <https://gitlab.fel.cvut.cz/canbus/zynq/zynq-can-sja1000-top>`_ +and Intel Cyclone V 5CSEMA4U23C6 based DE0-Nano-SoC Terasic board +`QSys integration <https://gitlab.fel.cvut.cz/canbus/intel-soc-ctucanfd>`_ +has been developed as well as support for +`PCIe integration <https://gitlab.fel.cvut.cz/canbus/pcie-ctucanfd>`_ of the core. + +In the case of Zynq, the core is connected via the APB system bus, which does +not have enumeration support, and the device must be specified in Device Tree. +This kind of devices is called platform device in the kernel and is +handled by a platform device driver. + +The basic functional model of the CTU CAN FD peripheral has been +accepted into QEMU mainline. See QEMU `CAN emulation support <https://www.qemu.org/docs/master/system/devices/can.html>`_ +for CAN FD buses, host connection and CTU CAN FD core emulation. The development +version of emulation support can be cloned from ctu-canfd branch of QEMU local +development `repository <https://gitlab.fel.cvut.cz/canbus/qemu-canbus>`_. + + +About SocketCAN +--------------- + +SocketCAN is a standard common interface for CAN devices in the Linux +kernel. As the name suggests, the bus is accessed via sockets, similarly +to common network devices. The reasoning behind this is in depth +described in `Linux SocketCAN <https://www.kernel.org/doc/html/latest/networking/can.html>`_. +In short, it offers a +natural way to implement and work with higher layer protocols over CAN, +in the same way as, e.g., UDP/IP over Ethernet. + +Device probe +~~~~~~~~~~~~ + +Before going into detail about the structure of a CAN bus device driver, +let's reiterate how the kernel gets to know about the device at all. +Some buses, like PCI or PCIe, support device enumeration. That is, when +the system boots, it discovers all the devices on the bus and reads +their configuration. The kernel identifies the device via its vendor ID +and device ID, and if there is a driver registered for this identifier +combination, its probe method is invoked to populate the driver's +instance for the given hardware. A similar situation goes with USB, only +it allows for device hot-plug. + +The situation is different for peripherals which are directly embedded +in the SoC and connected to an internal system bus (AXI, APB, Avalon, +and others). These buses do not support enumeration, and thus the kernel +has to learn about the devices from elsewhere. This is exactly what the +Device Tree was made for. + +Device tree +~~~~~~~~~~~ + +An entry in device tree states that a device exists in the system, how +it is reachable (on which bus it resides) and its configuration – +registers address, interrupts and so on. An example of such a device +tree is given in . + +:: + + / { + /* ... */ + amba: amba { + #address-cells = <1>; + #size-cells = <1>; + compatible = "simple-bus"; + + CTU_CAN_FD_0: CTU_CAN_FD@43c30000 { + compatible = "ctu,ctucanfd"; + interrupt-parent = <&intc>; + interrupts = <0 30 4>; + clocks = <&clkc 15>; + reg = <0x43c30000 0x10000>; + }; + }; + }; + + +.. _sec:socketcan:drv: + +Driver structure +~~~~~~~~~~~~~~~~ + +The driver can be divided into two parts – platform-dependent device +discovery and set up, and platform-independent CAN network device +implementation. + +.. _sec:socketcan:platdev: + +Platform device driver +^^^^^^^^^^^^^^^^^^^^^^ + +In the case of Zynq, the core is connected via the AXI system bus, which +does not have enumeration support, and the device must be specified in +Device Tree. This kind of devices is called *platform device* in the +kernel and is handled by a *platform device driver*\ [1]_. + +A platform device driver provides the following things: + +- A *probe* function + +- A *remove* function + +- A table of *compatible* devices that the driver can handle + +The *probe* function is called exactly once when the device appears (or +the driver is loaded, whichever happens later). If there are more +devices handled by the same driver, the *probe* function is called for +each one of them. Its role is to allocate and initialize resources +required for handling the device, as well as set up low-level functions +for the platform-independent layer, e.g., *read_reg* and *write_reg*. +After that, the driver registers the device to a higher layer, in our +case as a *network device*. + +The *remove* function is called when the device disappears, or the +driver is about to be unloaded. It serves to free the resources +allocated in *probe* and to unregister the device from higher layers. + +Finally, the table of *compatible* devices states which devices the +driver can handle. The Device Tree entry ``compatible`` is matched +against the tables of all *platform drivers*. + +.. code:: c + + /* Match table for OF platform binding */ + static const struct of_device_id ctucan_of_match[] = { + { .compatible = "ctu,canfd-2", }, + { .compatible = "ctu,ctucanfd", }, + { /* end of list */ }, + }; + MODULE_DEVICE_TABLE(of, ctucan_of_match); + + static int ctucan_probe(struct platform_device *pdev); + static int ctucan_remove(struct platform_device *pdev); + + static struct platform_driver ctucanfd_driver = { + .probe = ctucan_probe, + .remove = ctucan_remove, + .driver = { + .name = DRIVER_NAME, + .of_match_table = ctucan_of_match, + }, + }; + module_platform_driver(ctucanfd_driver); + + +.. _sec:socketcan:netdev: + +Network device driver +^^^^^^^^^^^^^^^^^^^^^ + +Each network device must support at least these operations: + +- Bring the device up: ``ndo_open`` + +- Bring the device down: ``ndo_close`` + +- Submit TX frames to the device: ``ndo_start_xmit`` + +- Signal TX completion and errors to the network subsystem: ISR + +- Submit RX frames to the network subsystem: ISR and NAPI + +There are two possible event sources: the device and the network +subsystem. Device events are usually signaled via an interrupt, handled +in an Interrupt Service Routine (ISR). Handlers for the events +originating in the network subsystem are then specified in +``struct net_device_ops``. + +When the device is brought up, e.g., by calling ``ip link set can0 up``, +the driver’s function ``ndo_open`` is called. It should validate the +interface configuration and configure and enable the device. The +analogous opposite is ``ndo_close``, called when the device is being +brought down, be it explicitly or implicitly. + +When the system should transmit a frame, it does so by calling +``ndo_start_xmit``, which enqueues the frame into the device. If the +device HW queue (FIFO, mailboxes or whatever the implementation is) +becomes full, the ``ndo_start_xmit`` implementation informs the network +subsystem that it should stop the TX queue (via ``netif_stop_queue``). +It is then re-enabled later in ISR when the device has some space +available again and is able to enqueue another frame. + +All the device events are handled in ISR, namely: + +#. **TX completion**. When the device successfully finishes transmitting + a frame, the frame is echoed locally. On error, an informative error + frame [2]_ is sent to the network subsystem instead. In both cases, + the software TX queue is resumed so that more frames may be sent. + +#. **Error condition**. If something goes wrong (e.g., the device goes + bus-off or RX overrun happens), error counters are updated, and + informative error frames are enqueued to SW RX queue. + +#. **RX buffer not empty**. In this case, read the RX frames and enqueue + them to SW RX queue. Usually NAPI is used as a middle layer (see ). + +.. _sec:socketcan:napi: + +NAPI +~~~~ + +The frequency of incoming frames can be high and the overhead to invoke +the interrupt service routine for each frame can cause significant +system load. There are multiple mechanisms in the Linux kernel to deal +with this situation. They evolved over the years of Linux kernel +development and enhancements. For network devices, the current standard +is NAPI – *the New API*. It is similar to classical top-half/bottom-half +interrupt handling in that it only acknowledges the interrupt in the ISR +and signals that the rest of the processing should be done in softirq +context. On top of that, it offers the possibility to *poll* for new +frames for a while. This has a potential to avoid the costly round of +enabling interrupts, handling an incoming IRQ in ISR, re-enabling the +softirq and switching context back to softirq. + +See :ref:`Documentation/networking/napi.rst <napi>` for more information. + +Integrating the core to Xilinx Zynq +----------------------------------- + +The core interfaces a simple subset of the Avalon +(search for Intel **Avalon Interface Specifications**) +bus as it was originally used on +Alterra FPGA chips, yet Xilinx natively interfaces with AXI +(search for ARM **AMBA AXI and ACE Protocol Specification AXI3, +AXI4, and AXI4-Lite, ACE and ACE-Lite**). +The most obvious solution would be to use +an Avalon/AXI bridge or implement some simple conversion entity. +However, the core’s interface is half-duplex with no handshake +signaling, whereas AXI is full duplex with two-way signaling. Moreover, +even AXI-Lite slave interface is quite resource-intensive, and the +flexibility and speed of AXI are not required for a CAN core. + +Thus a much simpler bus was chosen – APB (Advanced Peripheral Bus) +(search for ARM **AMBA APB Protocol Specification**). +APB-AXI bridge is directly available in +Xilinx Vivado, and the interface adaptor entity is just a few simple +combinatorial assignments. + +Finally, to be able to include the core in a block diagram as a custom +IP, the core, together with the APB interface, has been packaged as a +Vivado component. + +CTU CAN FD Driver design +------------------------ + +The general structure of a CAN device driver has already been examined +in . The next paragraphs provide a more detailed description of the CTU +CAN FD core driver in particular. + +Low-level driver +~~~~~~~~~~~~~~~~ + +The core is not intended to be used solely with SocketCAN, and thus it +is desirable to have an OS-independent low-level driver. This low-level +driver can then be used in implementations of OS driver or directly +either on bare metal or in a user-space application. Another advantage +is that if the hardware slightly changes, only the low-level driver +needs to be modified. + +The code [3]_ is in part automatically generated and in part written +manually by the core author, with contributions of the thesis’ author. +The low-level driver supports operations such as: set bit timing, set +controller mode, enable/disable, read RX frame, write TX frame, and so +on. + +Configuring bit timing +~~~~~~~~~~~~~~~~~~~~~~ + +On CAN, each bit is divided into four segments: SYNC, PROP, PHASE1, and +PHASE2. Their duration is expressed in multiples of a Time Quantum +(details in `CAN Specification, Version 2.0 <http://esd.cs.ucr.edu/webres/can20.pdf>`_, chapter 8). +When configuring +bitrate, the durations of all the segments (and time quantum) must be +computed from the bitrate and Sample Point. This is performed +independently for both the Nominal bitrate and Data bitrate for CAN FD. + +SocketCAN is fairly flexible and offers either highly customized +configuration by setting all the segment durations manually, or a +convenient configuration by setting just the bitrate and sample point +(and even that is chosen automatically per Bosch recommendation if not +specified). However, each CAN controller may have different base clock +frequency and different width of segment duration registers. The +algorithm thus needs the minimum and maximum values for the durations +(and clock prescaler) and tries to optimize the numbers to fit both the +constraints and the requested parameters. + +.. code:: c + + struct can_bittiming_const { + char name[16]; /* Name of the CAN controller hardware */ + __u32 tseg1_min; /* Time segment 1 = prop_seg + phase_seg1 */ + __u32 tseg1_max; + __u32 tseg2_min; /* Time segment 2 = phase_seg2 */ + __u32 tseg2_max; + __u32 sjw_max; /* Synchronisation jump width */ + __u32 brp_min; /* Bit-rate prescaler */ + __u32 brp_max; + __u32 brp_inc; + }; + + +[lst:can_bittiming_const] + +A curious reader will notice that the durations of the segments PROP_SEG +and PHASE_SEG1 are not determined separately but rather combined and +then, by default, the resulting TSEG1 is evenly divided between PROP_SEG +and PHASE_SEG1. In practice, this has virtually no consequences as the +sample point is between PHASE_SEG1 and PHASE_SEG2. In CTU CAN FD, +however, the duration registers ``PROP`` and ``PH1`` have different +widths (6 and 7 bits, respectively), so the auto-computed values might +overflow the shorter register and must thus be redistributed among the +two [4]_. + +Handling RX +~~~~~~~~~~~ + +Frame reception is handled in NAPI queue, which is enabled from ISR when +the RXNE (RX FIFO Not Empty) bit is set. Frames are read one by one +until either no frame is left in the RX FIFO or the maximum work quota +has been reached for the NAPI poll run (see ). Each frame is then passed +to the network interface RX queue. + +An incoming frame may be either a CAN 2.0 frame or a CAN FD frame. The +way to distinguish between these two in the kernel is to allocate either +``struct can_frame`` or ``struct canfd_frame``, the two having different +sizes. In the controller, the information about the frame type is stored +in the first word of RX FIFO. + +This brings us a chicken-egg problem: we want to allocate the ``skb`` +for the frame, and only if it succeeds, fetch the frame from FIFO; +otherwise keep it there for later. But to be able to allocate the +correct ``skb``, we have to fetch the first work of FIFO. There are +several possible solutions: + +#. Read the word, then allocate. If it fails, discard the rest of the + frame. When the system is low on memory, the situation is bad anyway. + +#. Always allocate ``skb`` big enough for an FD frame beforehand. Then + tweak the ``skb`` internals to look like it has been allocated for + the smaller CAN 2.0 frame. + +#. Add option to peek into the FIFO instead of consuming the word. + +#. If the allocation fails, store the read word into driver’s data. On + the next try, use the stored word instead of reading it again. + +Option 1 is simple enough, but not very satisfying if we could do +better. Option 2 is not acceptable, as it would require modifying the +private state of an integral kernel structure. The slightly higher +memory consumption is just a virtual cherry on top of the “cake”. Option +3 requires non-trivial HW changes and is not ideal from the HW point of +view. + +Option 4 seems like a good compromise, with its disadvantage being that +a partial frame may stay in the FIFO for a prolonged time. Nonetheless, +there may be just one owner of the RX FIFO, and thus no one else should +see the partial frame (disregarding some exotic debugging scenarios). +Basides, the driver resets the core on its initialization, so the +partial frame cannot be “adopted” either. In the end, option 4 was +selected [5]_. + +.. _subsec:ctucanfd:rxtimestamp: + +Timestamping RX frames +^^^^^^^^^^^^^^^^^^^^^^ + +The CTU CAN FD core reports the exact timestamp when the frame has been +received. The timestamp is by default captured at the sample point of +the last bit of EOF but is configurable to be captured at the SOF bit. +The timestamp source is external to the core and may be up to 64 bits +wide. At the time of writing, passing the timestamp from kernel to +userspace is not yet implemented, but is planned in the future. + +Handling TX +~~~~~~~~~~~ + +The CTU CAN FD core has 4 independent TX buffers, each with its own +state and priority. When the core wants to transmit, a TX buffer in +Ready state with the highest priority is selected. + +The priorities are 3bit numbers in register TX_PRIORITY +(nibble-aligned). This should be flexible enough for most use cases. +SocketCAN, however, supports only one FIFO queue for outgoing +frames [6]_. The buffer priorities may be used to simulate the FIFO +behavior by assigning each buffer a distinct priority and *rotating* the +priorities after a frame transmission is completed. + +In addition to priority rotation, the SW must maintain head and tail +pointers into the FIFO formed by the TX buffers to be able to determine +which buffer should be used for next frame (``txb_head``) and which +should be the first completed one (``txb_tail``). The actual buffer +indices are (obviously) modulo 4 (number of TX buffers), but the +pointers must be at least one bit wider to be able to distinguish +between FIFO full and FIFO empty – in this situation, +:math:`txb\_head \equiv txb\_tail\ (\textrm{mod}\ 4)`. An example of how +the FIFO is maintained, together with priority rotation, is depicted in + +| + ++------+---+---+---+---+ +| TXB# | 0 | 1 | 2 | 3 | ++======+===+===+===+===+ +| Seq | A | B | C | | ++------+---+---+---+---+ +| Prio | 7 | 6 | 5 | 4 | ++------+---+---+---+---+ +| | | T | | H | ++------+---+---+---+---+ + +| + ++------+---+---+---+---+ +| TXB# | 0 | 1 | 2 | 3 | ++======+===+===+===+===+ +| Seq | | B | C | | ++------+---+---+---+---+ +| Prio | 4 | 7 | 6 | 5 | ++------+---+---+---+---+ +| | | T | | H | ++------+---+---+---+---+ + +| + ++------+---+---+---+---+----+ +| TXB# | 0 | 1 | 2 | 3 | 0’ | ++======+===+===+===+===+====+ +| Seq | E | B | C | D | | ++------+---+---+---+---+----+ +| Prio | 4 | 7 | 6 | 5 | | ++------+---+---+---+---+----+ +| | | T | | | H | ++------+---+---+---+---+----+ + +| + +.. kernel-figure:: fsm_txt_buffer_user.svg + + TX Buffer states with possible transitions + +.. _subsec:ctucanfd:txtimestamp: + +Timestamping TX frames +^^^^^^^^^^^^^^^^^^^^^^ + +When submitting a frame to a TX buffer, one may specify the timestamp at +which the frame should be transmitted. The frame transmission may start +later, but not sooner. Note that the timestamp does not participate in +buffer prioritization – that is decided solely by the mechanism +described above. + +Support for time-based packet transmission was recently merged to Linux +v4.19 `Time-based packet transmission <https://lwn.net/Articles/748879/>`_, +but it remains yet to be researched +whether this functionality will be practical for CAN. + +Also similarly to retrieving the timestamp of RX frames, the core +supports retrieving the timestamp of TX frames – that is the time when +the frame was successfully delivered. The particulars are very similar +to timestamping RX frames and are described in . + +Handling RX buffer overrun +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +When a received frame does no more fit into the hardware RX FIFO in its +entirety, RX FIFO overrun flag (STATUS[DOR]) is set and Data Overrun +Interrupt (DOI) is triggered. When servicing the interrupt, care must be +taken first to clear the DOR flag (via COMMAND[CDO]) and after that +clear the DOI interrupt flag. Otherwise, the interrupt would be +immediately [7]_ rearmed. + +**Note**: During development, it was discussed whether the internal HW +pipelining cannot disrupt this clear sequence and whether an additional +dummy cycle is necessary between clearing the flag and the interrupt. On +the Avalon interface, it indeed proved to be the case, but APB being +safe because it uses 2-cycle transactions. Essentially, the DOR flag +would be cleared, but DOI register’s Preset input would still be high +the cycle when the DOI clear request would also be applied (by setting +the register’s Reset input high). As Set had higher priority than Reset, +the DOI flag would not be reset. This has been already fixed by swapping +the Set/Reset priority (see issue #187). + +Reporting Error Passive and Bus Off conditions +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +It may be desirable to report when the node reaches *Error Passive*, +*Error Warning*, and *Bus Off* conditions. The driver is notified about +error state change by an interrupt (EPI, EWLI), and then proceeds to +determine the core’s error state by reading its error counters. + +There is, however, a slight race condition here – there is a delay +between the time when the state transition occurs (and the interrupt is +triggered) and when the error counters are read. When EPI is received, +the node may be either *Error Passive* or *Bus Off*. If the node goes +*Bus Off*, it obviously remains in the state until it is reset. +Otherwise, the node is *or was* *Error Passive*. However, it may happen +that the read state is *Error Warning* or even *Error Active*. It may be +unclear whether and what exactly to report in that case, but I +personally entertain the idea that the past error condition should still +be reported. Similarly, when EWLI is received but the state is later +detected to be *Error Passive*, *Error Passive* should be reported. + + +CTU CAN FD Driver Sources Reference +----------------------------------- + +.. kernel-doc:: drivers/net/can/ctucanfd/ctucanfd.h + :internal: + +.. kernel-doc:: drivers/net/can/ctucanfd/ctucanfd_base.c + :internal: + +.. kernel-doc:: drivers/net/can/ctucanfd/ctucanfd_pci.c + :internal: + +.. kernel-doc:: drivers/net/can/ctucanfd/ctucanfd_platform.c + :internal: + +CTU CAN FD IP Core and Driver Development Acknowledgment +--------------------------------------------------------- + +* Odrej Ille <ondrej.ille@gmail.com> + + * started the project as student at Department of Measurement, FEE, CTU + * invested great amount of personal time and enthusiasm to the project over years + * worked on more funded tasks + +* `Department of Measurement <https://meas.fel.cvut.cz/>`_, + `Faculty of Electrical Engineering <http://www.fel.cvut.cz/en/>`_, + `Czech Technical University <https://www.cvut.cz/en>`_ + + * is the main investor into the project over many years + * uses project in their CAN/CAN FD diagnostics framework for `Skoda Auto <https://www.skoda-auto.cz/>`_ + +* `Digiteq Automotive <https://www.digiteqautomotive.com/en>`_ + + * funding of the project CAN FD Open Cores Support Linux Kernel Based Systems + * negotiated and paid CTU to allow public access to the project + * provided additional funding of the work + +* `Department of Control Engineering <https://control.fel.cvut.cz/en>`_, + `Faculty of Electrical Engineering <http://www.fel.cvut.cz/en/>`_, + `Czech Technical University <https://www.cvut.cz/en>`_ + + * solving the project CAN FD Open Cores Support Linux Kernel Based Systems + * providing GitLab management + * virtual servers and computational power for continuous integration + * providing hardware for HIL continuous integration tests + +* `PiKRON Ltd. <http://pikron.com/>`_ + + * minor funding to initiate preparation of the project open-sourcing + +* Petr Porazil <porazil@pikron.com> + + * design of PCIe transceiver addon board and assembly of boards + * design and assembly of MZ_APO baseboard for MicroZed/Zynq based system + +* Martin Jerabek <martin.jerabek01@gmail.com> + + * Linux driver development + * continuous integration platform architect and GHDL updates + * thesis `Open-source and Open-hardware CAN FD Protocol Support <https://dspace.cvut.cz/bitstream/handle/10467/80366/F3-DP-2019-Jerabek-Martin-Jerabek-thesis-2019-canfd.pdf>`_ + +* Jiri Novak <jnovak@fel.cvut.cz> + + * project initiation, management and use at Department of Measurement, FEE, CTU + +* Pavel Pisa <pisa@cmp.felk.cvut.cz> + + * initiate open-sourcing, project coordination, management at Department of Control Engineering, FEE, CTU + +* Jaroslav Beran<jara.beran@gmail.com> + + * system integration for Intel SoC, core and driver testing and updates + +* Carsten Emde (`OSADL <https://www.osadl.org/>`_) + + * provided OSADL expertise to discuss IP core licensing + * pointed to possible deadlock for LGPL and CAN bus possible patent case which lead to relicense IP core design to BSD like license + +* Reiner Zitzmann and Holger Zeltwanger (`CAN in Automation <https://www.can-cia.org/>`_) + + * provided suggestions and help to inform community about the project and invited us to events focused on CAN bus future development directions + +* Jan Charvat + + * implemented CTU CAN FD functional model for QEMU which has been integrated into QEMU mainline (`docs/system/devices/can.rst <https://www.qemu.org/docs/master/system/devices/can.html>`_) + * Bachelor thesis Model of CAN FD Communication Controller for QEMU Emulator + +Notes +----- + + +.. [1] + Other buses have their own specific driver interface to set up the + device. + +.. [2] + Not to be mistaken with CAN Error Frame. This is a ``can_frame`` with + ``CAN_ERR_FLAG`` set and some error info in its ``data`` field. + +.. [3] + Available in CTU CAN FD repository + `<https://gitlab.fel.cvut.cz/canbus/ctucanfd_ip_core>`_ + +.. [4] + As is done in the low-level driver functions + ``ctucan_hw_set_nom_bittiming`` and + ``ctucan_hw_set_data_bittiming``. + +.. [5] + At the time of writing this thesis, option 1 is still being used and + the modification is queued in gitlab issue #222 + +.. [6] + Strictly speaking, multiple CAN TX queues are supported since v4.19 + `can: enable multi-queue for SocketCAN devices <https://lore.kernel.org/patchwork/patch/913526/>`_ but no mainline driver is using + them yet. + +.. 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b/Documentation/networking/device_drivers/can/freescale/flexcan.rst new file mode 100644 index 0000000000..106cd28901 --- /dev/null +++ b/Documentation/networking/device_drivers/can/freescale/flexcan.rst @@ -0,0 +1,54 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +============================= +Flexcan CAN Controller driver +============================= + +Authors: Marc Kleine-Budde <mkl@pengutronix.de>, +Dario Binacchi <dario.binacchi@amarulasolutions.com> + +On/off RTR frames reception +=========================== + +For most flexcan IP cores the driver supports 2 RX modes: + +- FIFO +- mailbox + +The older flexcan cores (integrated into the i.MX25, i.MX28, i.MX35 +and i.MX53 SOCs) only receive RTR frames if the controller is +configured for RX-FIFO mode. + +The RX FIFO mode uses a hardware FIFO with a depth of 6 CAN frames, +while the mailbox mode uses a software FIFO with a depth of up to 62 +CAN frames. With the help of the bigger buffer, the mailbox mode +performs better under high system load situations. + +As reception of RTR frames is part of the CAN standard, all flexcan +cores come up in a mode where RTR reception is possible. + +With the "rx-rtr" private flag the ability to receive RTR frames can +be waived at the expense of losing the ability to receive RTR +messages. This trade off is beneficial in certain use cases. + +"rx-rtr" on + Receive RTR frames. (default) + + The CAN controller can and will receive RTR frames. + + On some IP cores the controller cannot receive RTR frames in the + more performant "RX mailbox" mode and will use "RX FIFO" mode + instead. + +"rx-rtr" off + + Waive ability to receive RTR frames. (not supported on all IP cores) + + This mode activates the "RX mailbox mode" for better performance, on + some IP cores RTR frames cannot be received anymore. + +The setting can only be changed if the interface is down:: + + ip link set dev can0 down + ethtool --set-priv-flags can0 rx-rtr {off|on} + ip link set dev can0 up diff --git a/Documentation/networking/device_drivers/can/index.rst b/Documentation/networking/device_drivers/can/index.rst new file mode 100644 index 0000000000..6a8a4f74fa --- /dev/null +++ b/Documentation/networking/device_drivers/can/index.rst @@ -0,0 +1,22 @@ +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) + +Controller Area Network (CAN) Device Drivers +============================================ + +Device drivers for CAN devices. + +Contents: + +.. toctree:: + :maxdepth: 2 + + can327 + ctu/ctucanfd-driver + freescale/flexcan + +.. only:: subproject and html + + Indices + ======= + + * :ref:`genindex` diff --git a/Documentation/networking/device_drivers/cellular/index.rst b/Documentation/networking/device_drivers/cellular/index.rst new file mode 100644 index 0000000000..fc1812d3fc --- /dev/null +++ b/Documentation/networking/device_drivers/cellular/index.rst @@ -0,0 +1,18 @@ +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) + +Cellular Modem Device Drivers +============================= + +Contents: + +.. toctree:: + :maxdepth: 2 + + qualcomm/rmnet + +.. only:: subproject and html + + Indices + ======= + + * :ref:`genindex` diff --git a/Documentation/networking/device_drivers/cellular/qualcomm/rmnet.rst b/Documentation/networking/device_drivers/cellular/qualcomm/rmnet.rst new file mode 100644 index 0000000000..289c146a82 --- /dev/null +++ b/Documentation/networking/device_drivers/cellular/qualcomm/rmnet.rst @@ -0,0 +1,196 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============ +Rmnet Driver +============ + +1. Introduction +=============== + +rmnet driver is used for supporting the Multiplexing and aggregation +Protocol (MAP). This protocol is used by all recent chipsets using Qualcomm +Technologies, Inc. modems. + +This driver can be used to register onto any physical network device in +IP mode. Physical transports include USB, HSIC, PCIe and IP accelerator. + +Multiplexing allows for creation of logical netdevices (rmnet devices) to +handle multiple private data networks (PDN) like a default internet, tethering, +multimedia messaging service (MMS) or IP media subsystem (IMS). Hardware sends +packets with MAP headers to rmnet. Based on the multiplexer id, rmnet +routes to the appropriate PDN after removing the MAP header. + +Aggregation is required to achieve high data rates. This involves hardware +sending aggregated bunch of MAP frames. rmnet driver will de-aggregate +these MAP frames and send them to appropriate PDN's. + +2. Packet format +================ + +a. MAP packet v1 (data / control) + +MAP header fields are in big endian format. + +Packet format:: + + Bit 0 1 2-7 8-15 16-31 + Function Command / Data Reserved Pad Multiplexer ID Payload length + + Bit 32-x + Function Raw bytes + +Command (1)/ Data (0) bit value is to indicate if the packet is a MAP command +or data packet. Command packet is used for transport level flow control. Data +packets are standard IP packets. + +Reserved bits must be zero when sent and ignored when received. + +Padding is the number of bytes to be appended to the payload to +ensure 4 byte alignment. + +Multiplexer ID is to indicate the PDN on which data has to be sent. + +Payload length includes the padding length but does not include MAP header +length. + +b. Map packet v4 (data / control) + +MAP header fields are in big endian format. + +Packet format:: + + Bit 0 1 2-7 8-15 16-31 + Function Command / Data Reserved Pad Multiplexer ID Payload length + + Bit 32-(x-33) (x-32)-x + Function Raw bytes Checksum offload header + +Command (1)/ Data (0) bit value is to indicate if the packet is a MAP command +or data packet. Command packet is used for transport level flow control. Data +packets are standard IP packets. + +Reserved bits must be zero when sent and ignored when received. + +Padding is the number of bytes to be appended to the payload to +ensure 4 byte alignment. + +Multiplexer ID is to indicate the PDN on which data has to be sent. + +Payload length includes the padding length but does not include MAP header +length. + +Checksum offload header, has the information about the checksum processing done +by the hardware.Checksum offload header fields are in big endian format. + +Packet format:: + + Bit 0-14 15 16-31 + Function Reserved Valid Checksum start offset + + Bit 31-47 48-64 + Function Checksum length Checksum value + +Reserved bits must be zero when sent and ignored when received. + +Valid bit indicates whether the partial checksum is calculated and is valid. +Set to 1, if its is valid. Set to 0 otherwise. + +Padding is the number of bytes to be appended to the payload to +ensure 4 byte alignment. + +Checksum start offset, Indicates the offset in bytes from the beginning of the +IP header, from which modem computed checksum. + +Checksum length is the Length in bytes starting from CKSUM_START_OFFSET, +over which checksum is computed. + +Checksum value, indicates the checksum computed. + +c. MAP packet v5 (data / control) + +MAP header fields are in big endian format. + +Packet format:: + + Bit 0 1 2-7 8-15 16-31 + Function Command / Data Next header Pad Multiplexer ID Payload length + + Bit 32-x + Function Raw bytes + +Command (1)/ Data (0) bit value is to indicate if the packet is a MAP command +or data packet. Command packet is used for transport level flow control. Data +packets are standard IP packets. + +Next header is used to indicate the presence of another header, currently is +limited to checksum header. + +Padding is the number of bytes to be appended to the payload to +ensure 4 byte alignment. + +Multiplexer ID is to indicate the PDN on which data has to be sent. + +Payload length includes the padding length but does not include MAP header +length. + +d. Checksum offload header v5 + +Checksum offload header fields are in big endian format. + + Bit 0 - 6 7 8-15 16-31 + Function Header Type Next Header Checksum Valid Reserved + +Header Type is to indicate the type of header, this usually is set to CHECKSUM + +Header types += ========================================== +0 Reserved +1 Reserved +2 checksum header + +Checksum Valid is to indicate whether the header checksum is valid. Value of 1 +implies that checksum is calculated on this packet and is valid, value of 0 +indicates that the calculated packet checksum is invalid. + +Reserved bits must be zero when sent and ignored when received. + +e. MAP packet v1/v5 (command specific):: + + Bit 0 1 2-7 8 - 15 16 - 31 + Function Command Reserved Pad Multiplexer ID Payload length + Bit 32 - 39 40 - 45 46 - 47 48 - 63 + Function Command name Reserved Command Type Reserved + Bit 64 - 95 + Function Transaction ID + Bit 96 - 127 + Function Command data + +Command 1 indicates disabling flow while 2 is enabling flow + +Command types + += ========================================== +0 for MAP command request +1 is to acknowledge the receipt of a command +2 is for unsupported commands +3 is for error during processing of commands += ========================================== + +f. Aggregation + +Aggregation is multiple MAP packets (can be data or command) delivered to +rmnet in a single linear skb. rmnet will process the individual +packets and either ACK the MAP command or deliver the IP packet to the +network stack as needed + +MAP header|IP Packet|Optional padding|MAP header|IP Packet|Optional padding.... + +MAP header|IP Packet|Optional padding|MAP header|Command Packet|Optional pad... + +3. Userspace configuration +========================== + +rmnet userspace configuration is done through netlink using iproute2 +https://git.kernel.org/pub/scm/network/iproute2/iproute2.git/ + +The driver uses rtnl_link_ops for communication. diff --git a/Documentation/networking/device_drivers/ethernet/3com/3c509.rst b/Documentation/networking/device_drivers/ethernet/3com/3c509.rst new file mode 100644 index 0000000000..47f706bacd --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/3com/3c509.rst @@ -0,0 +1,249 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================================================================= +Linux and the 3Com EtherLink III Series Ethercards (driver v1.18c and higher) +============================================================================= + +This file contains the instructions and caveats for v1.18c and higher versions +of the 3c509 driver. You should not use the driver without reading this file. + +release 1.0 + +28 February 2002 + +Current maintainer (corrections to): + David Ruggiero <jdr@farfalle.com> + +Introduction +============ + +The following are notes and information on using the 3Com EtherLink III series +ethercards in Linux. These cards are commonly known by the most widely-used +card's 3Com model number, 3c509. They are all 10mb/s ISA-bus cards and shouldn't +be (but sometimes are) confused with the similarly-numbered PCI-bus "3c905" +(aka "Vortex" or "Boomerang") series. Kernel support for the 3c509 family is +provided by the module 3c509.c, which has code to support all of the following +models: + + - 3c509 (original ISA card) + - 3c509B (later revision of the ISA card; supports full-duplex) + - 3c589 (PCMCIA) + - 3c589B (later revision of the 3c589; supports full-duplex) + - 3c579 (EISA) + +Large portions of this documentation were heavily borrowed from the guide +written the original author of the 3c509 driver, Donald Becker. The master +copy of that document, which contains notes on older versions of the driver, +currently resides on Scyld web server: http://www.scyld.com/. + + +Special Driver Features +======================= + +Overriding card settings + +The driver allows boot- or load-time overriding of the card's detected IOADDR, +IRQ, and transceiver settings, although this capability shouldn't generally be +needed except to enable full-duplex mode (see below). An example of the syntax +for LILO parameters for doing this:: + + ether=10,0x310,3,0x3c509,eth0 + +This configures the first found 3c509 card for IRQ 10, base I/O 0x310, and +transceiver type 3 (10base2). The flag "0x3c509" must be set to avoid conflicts +with other card types when overriding the I/O address. When the driver is +loaded as a module, only the IRQ may be overridden. For example, +setting two cards to IRQ10 and IRQ11 is done by using the irq module +option:: + + options 3c509 irq=10,11 + + +Full-duplex mode +================ + +The v1.18c driver added support for the 3c509B's full-duplex capabilities. +In order to enable and successfully use full-duplex mode, three conditions +must be met: + +(a) You must have a Etherlink III card model whose hardware supports full- +duplex operations. Currently, the only members of the 3c509 family that are +positively known to support full-duplex are the 3c509B (ISA bus) and 3c589B +(PCMCIA) cards. Cards without the "B" model designation do *not* support +full-duplex mode; these include the original 3c509 (no "B"), the original +3c589, the 3c529 (MCA bus), and the 3c579 (EISA bus). + +(b) You must be using your card's 10baseT transceiver (i.e., the RJ-45 +connector), not its AUI (thick-net) or 10base2 (thin-net/coax) interfaces. +AUI and 10base2 network cabling is physically incapable of full-duplex +operation. + +(c) Most importantly, your 3c509B must be connected to a link partner that is +itself full-duplex capable. This is almost certainly one of two things: a full- +duplex-capable Ethernet switch (*not* a hub), or a full-duplex-capable NIC on +another system that's connected directly to the 3c509B via a crossover cable. + +Full-duplex mode can be enabled using 'ethtool'. + +.. warning:: + + Extremely important caution concerning full-duplex mode + + Understand that the 3c509B's hardware's full-duplex support is much more + limited than that provide by more modern network interface cards. Although + at the physical layer of the network it fully supports full-duplex operation, + the card was designed before the current Ethernet auto-negotiation (N-way) + spec was written. This means that the 3c509B family ***cannot and will not + auto-negotiate a full-duplex connection with its link partner under any + circumstances, no matter how it is initialized***. If the full-duplex mode + of the 3c509B is enabled, its link partner will very likely need to be + independently _forced_ into full-duplex mode as well; otherwise various nasty + failures will occur - at the very least, you'll see massive numbers of packet + collisions. This is one of very rare circumstances where disabling auto- + negotiation and forcing the duplex mode of a network interface card or switch + would ever be necessary or desirable. + + +Available Transceiver Types +=========================== + +For versions of the driver v1.18c and above, the available transceiver types are: + +== ========================================================================= +0 transceiver type from EEPROM config (normally 10baseT); force half-duplex +1 AUI (thick-net / DB15 connector) +2 (undefined) +3 10base2 (thin-net == coax / BNC connector) +4 10baseT (RJ-45 connector); force half-duplex mode +8 transceiver type and duplex mode taken from card's EEPROM config settings +12 10baseT (RJ-45 connector); force full-duplex mode +== ========================================================================= + +Prior to driver version 1.18c, only transceiver codes 0-4 were supported. Note +that the new transceiver codes 8 and 12 are the *only* ones that will enable +full-duplex mode, no matter what the card's detected EEPROM settings might be. +This insured that merely upgrading the driver from an earlier version would +never automatically enable full-duplex mode in an existing installation; +it must always be explicitly enabled via one of these code in order to be +activated. + +The transceiver type can be changed using 'ethtool'. + + +Interpretation of error messages and common problems +---------------------------------------------------- + +Error Messages +^^^^^^^^^^^^^^ + +eth0: Infinite loop in interrupt, status 2011. +These are "mostly harmless" message indicating that the driver had too much +work during that interrupt cycle. With a status of 0x2011 you are receiving +packets faster than they can be removed from the card. This should be rare +or impossible in normal operation. Possible causes of this error report are: + + - a "green" mode enabled that slows the processor down when there is no + keyboard activity. + + - some other device or device driver hogging the bus or disabling interrupts. + Check /proc/interrupts for excessive interrupt counts. The timer tick + interrupt should always be incrementing faster than the others. + +No received packets +^^^^^^^^^^^^^^^^^^^ + +If a 3c509, 3c562 or 3c589 can successfully transmit packets, but never +receives packets (as reported by /proc/net/dev or 'ifconfig') you likely +have an interrupt line problem. Check /proc/interrupts to verify that the +card is actually generating interrupts. If the interrupt count is not +increasing you likely have a physical conflict with two devices trying to +use the same ISA IRQ line. The common conflict is with a sound card on IRQ10 +or IRQ5, and the easiest solution is to move the 3c509 to a different +interrupt line. If the device is receiving packets but 'ping' doesn't work, +you have a routing problem. + +Tx Carrier Errors Reported in /proc/net/dev +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + + +If an EtherLink III appears to transmit packets, but the "Tx carrier errors" +field in /proc/net/dev increments as quickly as the Tx packet count, you +likely have an unterminated network or the incorrect media transceiver selected. + +3c509B card is not detected on machines with an ISA PnP BIOS. +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +While the updated driver works with most PnP BIOS programs, it does not work +with all. This can be fixed by disabling PnP support using the 3Com-supplied +setup program. + +3c509 card is not detected on overclocked machines +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Increase the delay time in id_read_eeprom() from the current value, 500, +to an absurdly high value, such as 5000. + + +Decoding Status and Error Messages +---------------------------------- + + +The bits in the main status register are: + +===== ====================================== +value description +===== ====================================== +0x01 Interrupt latch +0x02 Tx overrun, or Rx underrun +0x04 Tx complete +0x08 Tx FIFO room available +0x10 A complete Rx packet has arrived +0x20 A Rx packet has started to arrive +0x40 The driver has requested an interrupt +0x80 Statistics counter nearly full +===== ====================================== + +The bits in the transmit (Tx) status word are: + +===== ============================================ +value description +===== ============================================ +0x02 Out-of-window collision. +0x04 Status stack overflow (normally impossible). +0x08 16 collisions. +0x10 Tx underrun (not enough PCI bus bandwidth). +0x20 Tx jabber. +0x40 Tx interrupt requested. +0x80 Status is valid (this should always be set). +===== ============================================ + + +When a transmit error occurs the driver produces a status message such as:: + + eth0: Transmit error, Tx status register 82 + +The two values typically seen here are: + +0x82 +^^^^ + +Out of window collision. This typically occurs when some other Ethernet +host is incorrectly set to full duplex on a half duplex network. + +0x88 +^^^^ + +16 collisions. This typically occurs when the network is exceptionally busy +or when another host doesn't correctly back off after a collision. If this +error is mixed with 0x82 errors it is the result of a host incorrectly set +to full duplex (see above). + +Both of these errors are the result of network problems that should be +corrected. They do not represent driver malfunction. + + +Revision history (this file) +============================ + +28Feb02 v1.0 DR New; major portions based on Becker original 3c509 docs + diff --git a/Documentation/networking/device_drivers/ethernet/3com/vortex.rst b/Documentation/networking/device_drivers/ethernet/3com/vortex.rst new file mode 100644 index 0000000000..a060f84c4f --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/3com/vortex.rst @@ -0,0 +1,459 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================= +3Com Vortex device driver +========================= + +Andrew Morton + +30 April 2000 + + +This document describes the usage and errata of the 3Com "Vortex" device +driver for Linux, 3c59x.c. + +The driver was written by Donald Becker <becker@scyld.com> + +Don is no longer the prime maintainer of this version of the driver. +Please report problems to one or more of: + +- Andrew Morton +- Netdev mailing list <netdev@vger.kernel.org> +- Linux kernel mailing list <linux-kernel@vger.kernel.org> + +Please note the 'Reporting and Diagnosing Problems' section at the end +of this file. + + +Since kernel 2.3.99-pre6, this driver incorporates the support for the +3c575-series Cardbus cards which used to be handled by 3c575_cb.c. + +This driver supports the following hardware: + + - 3c590 Vortex 10Mbps + - 3c592 EISA 10Mbps Demon/Vortex + - 3c597 EISA Fast Demon/Vortex + - 3c595 Vortex 100baseTx + - 3c595 Vortex 100baseT4 + - 3c595 Vortex 100base-MII + - 3c900 Boomerang 10baseT + - 3c900 Boomerang 10Mbps Combo + - 3c900 Cyclone 10Mbps TPO + - 3c900 Cyclone 10Mbps Combo + - 3c900 Cyclone 10Mbps TPC + - 3c900B-FL Cyclone 10base-FL + - 3c905 Boomerang 100baseTx + - 3c905 Boomerang 100baseT4 + - 3c905B Cyclone 100baseTx + - 3c905B Cyclone 10/100/BNC + - 3c905B-FX Cyclone 100baseFx + - 3c905C Tornado + - 3c920B-EMB-WNM (ATI Radeon 9100 IGP) + - 3c980 Cyclone + - 3c980C Python-T + - 3cSOHO100-TX Hurricane + - 3c555 Laptop Hurricane + - 3c556 Laptop Tornado + - 3c556B Laptop Hurricane + - 3c575 [Megahertz] 10/100 LAN CardBus + - 3c575 Boomerang CardBus + - 3CCFE575BT Cyclone CardBus + - 3CCFE575CT Tornado CardBus + - 3CCFE656 Cyclone CardBus + - 3CCFEM656B Cyclone+Winmodem CardBus + - 3CXFEM656C Tornado+Winmodem CardBus + - 3c450 HomePNA Tornado + - 3c920 Tornado + - 3c982 Hydra Dual Port A + - 3c982 Hydra Dual Port B + - 3c905B-T4 + - 3c920B-EMB-WNM Tornado + +Module parameters +================= + +There are several parameters which may be provided to the driver when +its module is loaded. These are usually placed in ``/etc/modprobe.d/*.conf`` +configuration files. Example:: + + options 3c59x debug=3 rx_copybreak=300 + +If you are using the PCMCIA tools (cardmgr) then the options may be +placed in /etc/pcmcia/config.opts:: + + module "3c59x" opts "debug=3 rx_copybreak=300" + + +The supported parameters are: + +debug=N + + Where N is a number from 0 to 7. Anything above 3 produces a lot + of output in your system logs. debug=1 is default. + +options=N1,N2,N3,... + + Each number in the list provides an option to the corresponding + network card. So if you have two 3c905's and you wish to provide + them with option 0x204 you would use:: + + options=0x204,0x204 + + The individual options are composed of a number of bitfields which + have the following meanings: + + Possible media type settings + + == ================================= + 0 10baseT + 1 10Mbs AUI + 2 undefined + 3 10base2 (BNC) + 4 100base-TX + 5 100base-FX + 6 MII (Media Independent Interface) + 7 Use default setting from EEPROM + 8 Autonegotiate + 9 External MII + 10 Use default setting from EEPROM + == ================================= + + When generating a value for the 'options' setting, the above media + selection values may be OR'ed (or added to) the following: + + ====== ============================================= + 0x8000 Set driver debugging level to 7 + 0x4000 Set driver debugging level to 2 + 0x0400 Enable Wake-on-LAN + 0x0200 Force full duplex mode. + 0x0010 Bus-master enable bit (Old Vortex cards only) + ====== ============================================= + + For example:: + + insmod 3c59x options=0x204 + + will force full-duplex 100base-TX, rather than allowing the usual + autonegotiation. + +global_options=N + + Sets the ``options`` parameter for all 3c59x NICs in the machine. + Entries in the ``options`` array above will override any setting of + this. + +full_duplex=N1,N2,N3... + + Similar to bit 9 of 'options'. Forces the corresponding card into + full-duplex mode. Please use this in preference to the ``options`` + parameter. + + In fact, please don't use this at all! You're better off getting + autonegotiation working properly. + +global_full_duplex=N1 + + Sets full duplex mode for all 3c59x NICs in the machine. Entries + in the ``full_duplex`` array above will override any setting of this. + +flow_ctrl=N1,N2,N3... + + Use 802.3x MAC-layer flow control. The 3com cards only support the + PAUSE command, which means that they will stop sending packets for a + short period if they receive a PAUSE frame from the link partner. + + The driver only allows flow control on a link which is operating in + full duplex mode. + + This feature does not appear to work on the 3c905 - only 3c905B and + 3c905C have been tested. + + The 3com cards appear to only respond to PAUSE frames which are + sent to the reserved destination address of 01:80:c2:00:00:01. They + do not honour PAUSE frames which are sent to the station MAC address. + +rx_copybreak=M + + The driver preallocates 32 full-sized (1536 byte) network buffers + for receiving. When a packet arrives, the driver has to decide + whether to leave the packet in its full-sized buffer, or to allocate + a smaller buffer and copy the packet across into it. + + This is a speed/space tradeoff. + + The value of rx_copybreak is used to decide when to make the copy. + If the packet size is less than rx_copybreak, the packet is copied. + The default value for rx_copybreak is 200 bytes. + +max_interrupt_work=N + + The driver's interrupt service routine can handle many receive and + transmit packets in a single invocation. It does this in a loop. + The value of max_interrupt_work governs how many times the interrupt + service routine will loop. The default value is 32 loops. If this + is exceeded the interrupt service routine gives up and generates a + warning message "eth0: Too much work in interrupt". + +hw_checksums=N1,N2,N3,... + + Recent 3com NICs are able to generate IPv4, TCP and UDP checksums + in hardware. Linux has used the Rx checksumming for a long time. + The "zero copy" patch which is planned for the 2.4 kernel series + allows you to make use of the NIC's DMA scatter/gather and transmit + checksumming as well. + + The driver is set up so that, when the zerocopy patch is applied, + all Tornado and Cyclone devices will use S/G and Tx checksums. + + This module parameter has been provided so you can override this + decision. If you think that Tx checksums are causing a problem, you + may disable the feature with ``hw_checksums=0``. + + If you think your NIC should be performing Tx checksumming and the + driver isn't enabling it, you can force the use of hardware Tx + checksumming with ``hw_checksums=1``. + + The driver drops a message in the logfiles to indicate whether or + not it is using hardware scatter/gather and hardware Tx checksums. + + Scatter/gather and hardware checksums provide considerable + performance improvement for the sendfile() system call, but a small + decrease in throughput for send(). There is no effect upon receive + efficiency. + +compaq_ioaddr=N, +compaq_irq=N, +compaq_device_id=N + + "Variables to work-around the Compaq PCI BIOS32 problem".... + +watchdog=N + + Sets the time duration (in milliseconds) after which the kernel + decides that the transmitter has become stuck and needs to be reset. + This is mainly for debugging purposes, although it may be advantageous + to increase this value on LANs which have very high collision rates. + The default value is 5000 (5.0 seconds). + +enable_wol=N1,N2,N3,... + + Enable Wake-on-LAN support for the relevant interface. Donald + Becker's ``ether-wake`` application may be used to wake suspended + machines. + + Also enables the NIC's power management support. + +global_enable_wol=N + + Sets enable_wol mode for all 3c59x NICs in the machine. Entries in + the ``enable_wol`` array above will override any setting of this. + +Media selection +--------------- + +A number of the older NICs such as the 3c590 and 3c900 series have +10base2 and AUI interfaces. + +Prior to January, 2001 this driver would autoselect the 10base2 or AUI +port if it didn't detect activity on the 10baseT port. It would then +get stuck on the 10base2 port and a driver reload was necessary to +switch back to 10baseT. This behaviour could not be prevented with a +module option override. + +Later (current) versions of the driver _do_ support locking of the +media type. So if you load the driver module with + + modprobe 3c59x options=0 + +it will permanently select the 10baseT port. Automatic selection of +other media types does not occur. + + +Transmit error, Tx status register 82 +------------------------------------- + +This is a common error which is almost always caused by another host on +the same network being in full-duplex mode, while this host is in +half-duplex mode. You need to find that other host and make it run in +half-duplex mode or fix this host to run in full-duplex mode. + +As a last resort, you can force the 3c59x driver into full-duplex mode +with + + options 3c59x full_duplex=1 + +but this has to be viewed as a workaround for broken network gear and +should only really be used for equipment which cannot autonegotiate. + + +Additional resources +-------------------- + +Details of the device driver implementation are at the top of the source file. + +Additional documentation is available at Don Becker's Linux Drivers site: + + http://www.scyld.com/vortex.html + +Donald Becker's driver development site: + + http://www.scyld.com/network.html + +Donald's vortex-diag program is useful for inspecting the NIC's state: + + http://www.scyld.com/ethercard_diag.html + +Donald's mii-diag program may be used for inspecting and manipulating +the NIC's Media Independent Interface subsystem: + + http://www.scyld.com/ethercard_diag.html#mii-diag + +Donald's wake-on-LAN page: + + http://www.scyld.com/wakeonlan.html + +3Com's DOS-based application for setting up the NICs EEPROMs: + + ftp://ftp.3com.com/pub/nic/3c90x/3c90xx2.exe + + +Autonegotiation notes +--------------------- + + The driver uses a one-minute heartbeat for adapting to changes in + the external LAN environment if link is up and 5 seconds if link is down. + This means that when, for example, a machine is unplugged from a hubbed + 10baseT LAN plugged into a switched 100baseT LAN, the throughput + will be quite dreadful for up to sixty seconds. Be patient. + + Cisco interoperability note from Walter Wong <wcw+@CMU.EDU>: + + On a side note, adding HAS_NWAY seems to share a problem with the + Cisco 6509 switch. Specifically, you need to change the spanning + tree parameter for the port the machine is plugged into to 'portfast' + mode. Otherwise, the negotiation fails. This has been an issue + we've noticed for a while but haven't had the time to track down. + + Cisco switches (Jeff Busch <jbusch@deja.com>) + + My "standard config" for ports to which PC's/servers connect directly:: + + interface FastEthernet0/N + description machinename + load-interval 30 + spanning-tree portfast + + If autonegotiation is a problem, you may need to specify "speed + 100" and "duplex full" as well (or "speed 10" and "duplex half"). + + WARNING: DO NOT hook up hubs/switches/bridges to these + specially-configured ports! The switch will become very confused. + + +Reporting and diagnosing problems +--------------------------------- + +Maintainers find that accurate and complete problem reports are +invaluable in resolving driver problems. We are frequently not able to +reproduce problems and must rely on your patience and efforts to get to +the bottom of the problem. + +If you believe you have a driver problem here are some of the +steps you should take: + +- Is it really a driver problem? + + Eliminate some variables: try different cards, different + computers, different cables, different ports on the switch/hub, + different versions of the kernel or of the driver, etc. + +- OK, it's a driver problem. + + You need to generate a report. Typically this is an email to the + maintainer and/or netdev@vger.kernel.org. The maintainer's + email address will be in the driver source or in the MAINTAINERS file. + +- The contents of your report will vary a lot depending upon the + problem. If it's a kernel crash then you should refer to + 'Documentation/admin-guide/reporting-issues.rst'. + + But for most problems it is useful to provide the following: + + - Kernel version, driver version + + - A copy of the banner message which the driver generates when + it is initialised. For example: + + eth0: 3Com PCI 3c905C Tornado at 0xa400, 00:50:da:6a:88:f0, IRQ 19 + 8K byte-wide RAM 5:3 Rx:Tx split, autoselect/Autonegotiate interface. + MII transceiver found at address 24, status 782d. + Enabling bus-master transmits and whole-frame receives. + + NOTE: You must provide the ``debug=2`` modprobe option to generate + a full detection message. Please do this:: + + modprobe 3c59x debug=2 + + - If it is a PCI device, the relevant output from 'lspci -vx', eg:: + + 00:09.0 Ethernet controller: 3Com Corporation 3c905C-TX [Fast Etherlink] (rev 74) + Subsystem: 3Com Corporation: Unknown device 9200 + Flags: bus master, medium devsel, latency 32, IRQ 19 + I/O ports at a400 [size=128] + Memory at db000000 (32-bit, non-prefetchable) [size=128] + Expansion ROM at <unassigned> [disabled] [size=128K] + Capabilities: [dc] Power Management version 2 + 00: b7 10 00 92 07 00 10 02 74 00 00 02 08 20 00 00 + 10: 01 a4 00 00 00 00 00 db 00 00 00 00 00 00 00 00 + 20: 00 00 00 00 00 00 00 00 00 00 00 00 b7 10 00 10 + 30: 00 00 00 00 dc 00 00 00 00 00 00 00 05 01 0a 0a + + - A description of the environment: 10baseT? 100baseT? + full/half duplex? switched or hubbed? + + - Any additional module parameters which you may be providing to the driver. + + - Any kernel logs which are produced. The more the merrier. + If this is a large file and you are sending your report to a + mailing list, mention that you have the logfile, but don't send + it. If you're reporting direct to the maintainer then just send + it. + + To ensure that all kernel logs are available, add the + following line to /etc/syslog.conf:: + + kern.* /var/log/messages + + Then restart syslogd with:: + + /etc/rc.d/init.d/syslog restart + + (The above may vary, depending upon which Linux distribution you use). + + - If your problem is reproducible then that's great. Try the + following: + + 1) Increase the debug level. Usually this is done via: + + a) modprobe driver debug=7 + b) In /etc/modprobe.d/driver.conf: + options driver debug=7 + + 2) Recreate the problem with the higher debug level, + send all logs to the maintainer. + + 3) Download you card's diagnostic tool from Donald + Becker's website <http://www.scyld.com/ethercard_diag.html>. + Download mii-diag.c as well. Build these. + + a) Run 'vortex-diag -aaee' and 'mii-diag -v' when the card is + working correctly. Save the output. + + b) Run the above commands when the card is malfunctioning. Send + both sets of output. + +Finally, please be patient and be prepared to do some work. You may +end up working on this problem for a week or more as the maintainer +asks more questions, asks for more tests, asks for patches to be +applied, etc. At the end of it all, the problem may even remain +unresolved. diff --git a/Documentation/networking/device_drivers/ethernet/altera/altera_tse.rst b/Documentation/networking/device_drivers/ethernet/altera/altera_tse.rst new file mode 100644 index 0000000000..7a7040072e --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/altera/altera_tse.rst @@ -0,0 +1,286 @@ +.. SPDX-License-Identifier: GPL-2.0 + +.. include:: <isonum.txt> + +======================================= +Altera Triple-Speed Ethernet MAC driver +======================================= + +Copyright |copy| 2008-2014 Altera Corporation + +This is the driver for the Altera Triple-Speed Ethernet (TSE) controllers +using the SGDMA and MSGDMA soft DMA IP components. The driver uses the +platform bus to obtain component resources. The designs used to test this +driver were built for a Cyclone(R) V SOC FPGA board, a Cyclone(R) V FPGA board, +and tested with ARM and NIOS processor hosts separately. The anticipated use +cases are simple communications between an embedded system and an external peer +for status and simple configuration of the embedded system. + +For more information visit www.altera.com and www.rocketboards.org. Support +forums for the driver may be found on www.rocketboards.org, and a design used +to test this driver may be found there as well. Support is also available from +the maintainer of this driver, found in MAINTAINERS. + +The Triple-Speed Ethernet, SGDMA, and MSGDMA components are all soft IP +components that can be assembled and built into an FPGA using the Altera +Quartus toolchain. Quartus 13.1 and 14.0 were used to build the design that +this driver was tested against. The sopc2dts tool is used to create the +device tree for the driver, and may be found at rocketboards.org. + +The driver probe function examines the device tree and determines if the +Triple-Speed Ethernet instance is using an SGDMA or MSGDMA component. The +probe function then installs the appropriate set of DMA routines to +initialize, setup transmits, receives, and interrupt handling primitives for +the respective configurations. + +The SGDMA component is to be deprecated in the near future (over the next 1-2 +years as of this writing in early 2014) in favor of the MSGDMA component. +SGDMA support is included for existing designs and reference in case a +developer wishes to support their own soft DMA logic and driver support. Any +new designs should not use the SGDMA. + +The SGDMA supports only a single transmit or receive operation at a time, and +therefore will not perform as well compared to the MSGDMA soft IP. Please +visit www.altera.com for known, documented SGDMA errata. + +Scatter-gather DMA is not supported by the SGDMA or MSGDMA at this time. +Scatter-gather DMA will be added to a future maintenance update to this +driver. + +Jumbo frames are not supported at this time. + +The driver limits PHY operations to 10/100Mbps, and has not yet been fully +tested for 1Gbps. This support will be added in a future maintenance update. + +1. Kernel Configuration +======================= + +The kernel configuration option is ALTERA_TSE: + + Device Drivers ---> Network device support ---> Ethernet driver support ---> + Altera Triple-Speed Ethernet MAC support (ALTERA_TSE) + +2. Driver parameters list +========================= + + - debug: message level (0: no output, 16: all); + - dma_rx_num: Number of descriptors in the RX list (default is 64); + - dma_tx_num: Number of descriptors in the TX list (default is 64). + +3. Command line options +======================= + +Driver parameters can be also passed in command line by using:: + + altera_tse=dma_rx_num:128,dma_tx_num:512 + +4. Driver information and notes +=============================== + +4.1. Transmit process +--------------------- +When the driver's transmit routine is called by the kernel, it sets up a +transmit descriptor by calling the underlying DMA transmit routine (SGDMA or +MSGDMA), and initiates a transmit operation. Once the transmit is complete, an +interrupt is driven by the transmit DMA logic. The driver handles the transmit +completion in the context of the interrupt handling chain by recycling +resource required to send and track the requested transmit operation. + +4.2. Receive process +-------------------- +The driver will post receive buffers to the receive DMA logic during driver +initialization. Receive buffers may or may not be queued depending upon the +underlying DMA logic (MSGDMA is able queue receive buffers, SGDMA is not able +to queue receive buffers to the SGDMA receive logic). When a packet is +received, the DMA logic generates an interrupt. The driver handles a receive +interrupt by obtaining the DMA receive logic status, reaping receive +completions until no more receive completions are available. + +4.3. Interrupt Mitigation +------------------------- +The driver is able to mitigate the number of its DMA interrupts +using NAPI for receive operations. Interrupt mitigation is not yet supported +for transmit operations, but will be added in a future maintenance release. + +4.4) Ethtool support +-------------------- +Ethtool is supported. Driver statistics and internal errors can be taken using: +ethtool -S ethX command. It is possible to dump registers etc. + +4.5) PHY Support +---------------- +The driver is compatible with PAL to work with PHY and GPHY devices. + +4.7) List of source files: +-------------------------- + - Kconfig + - Makefile + - altera_tse_main.c: main network device driver + - altera_tse_ethtool.c: ethtool support + - altera_tse.h: private driver structure and common definitions + - altera_msgdma.h: MSGDMA implementation function definitions + - altera_sgdma.h: SGDMA implementation function definitions + - altera_msgdma.c: MSGDMA implementation + - altera_sgdma.c: SGDMA implementation + - altera_sgdmahw.h: SGDMA register and descriptor definitions + - altera_msgdmahw.h: MSGDMA register and descriptor definitions + - altera_utils.c: Driver utility functions + - altera_utils.h: Driver utility function definitions + +5. Debug Information +==================== + +The driver exports debug information such as internal statistics, +debug information, MAC and DMA registers etc. + +A user may use the ethtool support to get statistics: +e.g. using: ethtool -S ethX (that shows the statistics counters) +or sees the MAC registers: e.g. using: ethtool -d ethX + +The developer can also use the "debug" module parameter to get +further debug information. + +6. Statistics Support +===================== + +The controller and driver support a mix of IEEE standard defined statistics, +RFC defined statistics, and driver or Altera defined statistics. The four +specifications containing the standard definitions for these statistics are +as follows: + + - IEEE 802.3-2012 - IEEE Standard for Ethernet. + - RFC 2863 found at http://www.rfc-editor.org/rfc/rfc2863.txt. + - RFC 2819 found at http://www.rfc-editor.org/rfc/rfc2819.txt. + - Altera Triple Speed Ethernet User Guide, found at http://www.altera.com + +The statistics supported by the TSE and the device driver are as follows: + +"tx_packets" is equivalent to aFramesTransmittedOK defined in IEEE 802.3-2012, +Section 5.2.2.1.2. This statistics is the count of frames that are successfully +transmitted. + +"rx_packets" is equivalent to aFramesReceivedOK defined in IEEE 802.3-2012, +Section 5.2.2.1.5. This statistic is the count of frames that are successfully +received. This count does not include any error packets such as CRC errors, +length errors, or alignment errors. + +"rx_crc_errors" is equivalent to aFrameCheckSequenceErrors defined in IEEE +802.3-2012, Section 5.2.2.1.6. This statistic is the count of frames that are +an integral number of bytes in length and do not pass the CRC test as the frame +is received. + +"rx_align_errors" is equivalent to aAlignmentErrors defined in IEEE 802.3-2012, +Section 5.2.2.1.7. This statistic is the count of frames that are not an +integral number of bytes in length and do not pass the CRC test as the frame is +received. + +"tx_bytes" is equivalent to aOctetsTransmittedOK defined in IEEE 802.3-2012, +Section 5.2.2.1.8. This statistic is the count of data and pad bytes +successfully transmitted from the interface. + +"rx_bytes" is equivalent to aOctetsReceivedOK defined in IEEE 802.3-2012, +Section 5.2.2.1.14. This statistic is the count of data and pad bytes +successfully received by the controller. + +"tx_pause" is equivalent to aPAUSEMACCtrlFramesTransmitted defined in IEEE +802.3-2012, Section 30.3.4.2. This statistic is a count of PAUSE frames +transmitted from the network controller. + +"rx_pause" is equivalent to aPAUSEMACCtrlFramesReceived defined in IEEE +802.3-2012, Section 30.3.4.3. This statistic is a count of PAUSE frames +received by the network controller. + +"rx_errors" is equivalent to ifInErrors defined in RFC 2863. This statistic is +a count of the number of packets received containing errors that prevented the +packet from being delivered to a higher level protocol. + +"tx_errors" is equivalent to ifOutErrors defined in RFC 2863. This statistic +is a count of the number of packets that could not be transmitted due to errors. + +"rx_unicast" is equivalent to ifInUcastPkts defined in RFC 2863. This +statistic is a count of the number of packets received that were not addressed +to the broadcast address or a multicast group. + +"rx_multicast" is equivalent to ifInMulticastPkts defined in RFC 2863. This +statistic is a count of the number of packets received that were addressed to +a multicast address group. + +"rx_broadcast" is equivalent to ifInBroadcastPkts defined in RFC 2863. This +statistic is a count of the number of packets received that were addressed to +the broadcast address. + +"tx_discards" is equivalent to ifOutDiscards defined in RFC 2863. This +statistic is the number of outbound packets not transmitted even though an +error was not detected. An example of a reason this might occur is to free up +internal buffer space. + +"tx_unicast" is equivalent to ifOutUcastPkts defined in RFC 2863. This +statistic counts the number of packets transmitted that were not addressed to +a multicast group or broadcast address. + +"tx_multicast" is equivalent to ifOutMulticastPkts defined in RFC 2863. This +statistic counts the number of packets transmitted that were addressed to a +multicast group. + +"tx_broadcast" is equivalent to ifOutBroadcastPkts defined in RFC 2863. This +statistic counts the number of packets transmitted that were addressed to a +broadcast address. + +"ether_drops" is equivalent to etherStatsDropEvents defined in RFC 2819. +This statistic counts the number of packets dropped due to lack of internal +controller resources. + +"rx_total_bytes" is equivalent to etherStatsOctets defined in RFC 2819. +This statistic counts the total number of bytes received by the controller, +including error and discarded packets. + +"rx_total_packets" is equivalent to etherStatsPkts defined in RFC 2819. +This statistic counts the total number of packets received by the controller, +including error, discarded, unicast, multicast, and broadcast packets. + +"rx_undersize" is equivalent to etherStatsUndersizePkts defined in RFC 2819. +This statistic counts the number of correctly formed packets received less +than 64 bytes long. + +"rx_oversize" is equivalent to etherStatsOversizePkts defined in RFC 2819. +This statistic counts the number of correctly formed packets greater than 1518 +bytes long. + +"rx_64_bytes" is equivalent to etherStatsPkts64Octets defined in RFC 2819. +This statistic counts the total number of packets received that were 64 octets +in length. + +"rx_65_127_bytes" is equivalent to etherStatsPkts65to127Octets defined in RFC +2819. This statistic counts the total number of packets received that were +between 65 and 127 octets in length inclusive. + +"rx_128_255_bytes" is equivalent to etherStatsPkts128to255Octets defined in +RFC 2819. This statistic is the total number of packets received that were +between 128 and 255 octets in length inclusive. + +"rx_256_511_bytes" is equivalent to etherStatsPkts256to511Octets defined in +RFC 2819. This statistic is the total number of packets received that were +between 256 and 511 octets in length inclusive. + +"rx_512_1023_bytes" is equivalent to etherStatsPkts512to1023Octets defined in +RFC 2819. This statistic is the total number of packets received that were +between 512 and 1023 octets in length inclusive. + +"rx_1024_1518_bytes" is equivalent to etherStatsPkts1024to1518Octets define +in RFC 2819. This statistic is the total number of packets received that were +between 1024 and 1518 octets in length inclusive. + +"rx_gte_1519_bytes" is a statistic defined specific to the behavior of the +Altera TSE. This statistics counts the number of received good and errored +frames between the length of 1519 and the maximum frame length configured +in the frm_length register. See the Altera TSE User Guide for More details. + +"rx_jabbers" is equivalent to etherStatsJabbers defined in RFC 2819. This +statistic is the total number of packets received that were longer than 1518 +octets, and had either a bad CRC with an integral number of octets (CRC Error) +or a bad CRC with a non-integral number of octets (Alignment Error). + +"rx_runts" is equivalent to etherStatsFragments defined in RFC 2819. This +statistic is the total number of packets received that were less than 64 octets +in length and had either a bad CRC with an integral number of octets (CRC +error) or a bad CRC with a non-integral number of octets (Alignment Error). diff --git a/Documentation/networking/device_drivers/ethernet/amazon/ena.rst b/Documentation/networking/device_drivers/ethernet/amazon/ena.rst new file mode 100644 index 0000000000..5eaa3ab6c7 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/amazon/ena.rst @@ -0,0 +1,351 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================================================ +Linux kernel driver for Elastic Network Adapter (ENA) family +============================================================ + +Overview +======== + +ENA is a networking interface designed to make good use of modern CPU +features and system architectures. + +The ENA device exposes a lightweight management interface with a +minimal set of memory mapped registers and extendible command set +through an Admin Queue. + +The driver supports a range of ENA devices, is link-speed independent +(i.e., the same driver is used for 10GbE, 25GbE, 40GbE, etc), and has +a negotiated and extendible feature set. + +Some ENA devices support SR-IOV. This driver is used for both the +SR-IOV Physical Function (PF) and Virtual Function (VF) devices. + +ENA devices enable high speed and low overhead network traffic +processing by providing multiple Tx/Rx queue pairs (the maximum number +is advertised by the device via the Admin Queue), a dedicated MSI-X +interrupt vector per Tx/Rx queue pair, adaptive interrupt moderation, +and CPU cacheline optimized data placement. + +The ENA driver supports industry standard TCP/IP offload features such as +checksum offload. Receive-side scaling (RSS) is supported for multi-core +scaling. + +The ENA driver and its corresponding devices implement health +monitoring mechanisms such as watchdog, enabling the device and driver +to recover in a manner transparent to the application, as well as +debug logs. + +Some of the ENA devices support a working mode called Low-latency +Queue (LLQ), which saves several more microseconds. + +ENA Source Code Directory Structure +=================================== + +================= ====================================================== +ena_com.[ch] Management communication layer. This layer is + responsible for the handling all the management + (admin) communication between the device and the + driver. +ena_eth_com.[ch] Tx/Rx data path. +ena_admin_defs.h Definition of ENA management interface. +ena_eth_io_defs.h Definition of ENA data path interface. +ena_common_defs.h Common definitions for ena_com layer. +ena_regs_defs.h Definition of ENA PCI memory-mapped (MMIO) registers. +ena_netdev.[ch] Main Linux kernel driver. +ena_ethtool.c ethtool callbacks. +ena_pci_id_tbl.h Supported device IDs. +================= ====================================================== + +Management Interface: +===================== + +ENA management interface is exposed by means of: + +- PCIe Configuration Space +- Device Registers +- Admin Queue (AQ) and Admin Completion Queue (ACQ) +- Asynchronous Event Notification Queue (AENQ) + +ENA device MMIO Registers are accessed only during driver +initialization and are not used during further normal device +operation. + +AQ is used for submitting management commands, and the +results/responses are reported asynchronously through ACQ. + +ENA introduces a small set of management commands with room for +vendor-specific extensions. Most of the management operations are +framed in a generic Get/Set feature command. + +The following admin queue commands are supported: + +- Create I/O submission queue +- Create I/O completion queue +- Destroy I/O submission queue +- Destroy I/O completion queue +- Get feature +- Set feature +- Configure AENQ +- Get statistics + +Refer to ena_admin_defs.h for the list of supported Get/Set Feature +properties. + +The Asynchronous Event Notification Queue (AENQ) is a uni-directional +queue used by the ENA device to send to the driver events that cannot +be reported using ACQ. AENQ events are subdivided into groups. Each +group may have multiple syndromes, as shown below + +The events are: + +==================== =============== +Group Syndrome +==================== =============== +Link state change **X** +Fatal error **X** +Notification Suspend traffic +Notification Resume traffic +Keep-Alive **X** +==================== =============== + +ACQ and AENQ share the same MSI-X vector. + +Keep-Alive is a special mechanism that allows monitoring the device's health. +A Keep-Alive event is delivered by the device every second. +The driver maintains a watchdog (WD) handler which logs the current state and +statistics. If the keep-alive events aren't delivered as expected the WD resets +the device and the driver. + +Data Path Interface +=================== + +I/O operations are based on Tx and Rx Submission Queues (Tx SQ and Rx +SQ correspondingly). Each SQ has a completion queue (CQ) associated +with it. + +The SQs and CQs are implemented as descriptor rings in contiguous +physical memory. + +The ENA driver supports two Queue Operation modes for Tx SQs: + +- **Regular mode:** + In this mode the Tx SQs reside in the host's memory. The ENA + device fetches the ENA Tx descriptors and packet data from host + memory. + +- **Low Latency Queue (LLQ) mode or "push-mode":** + In this mode the driver pushes the transmit descriptors and the + first 96 bytes of the packet directly to the ENA device memory + space. The rest of the packet payload is fetched by the + device. For this operation mode, the driver uses a dedicated PCI + device memory BAR, which is mapped with write-combine capability. + + **Note that** not all ENA devices support LLQ, and this feature is negotiated + with the device upon initialization. If the ENA device does not + support LLQ mode, the driver falls back to the regular mode. + +The Rx SQs support only the regular mode. + +The driver supports multi-queue for both Tx and Rx. This has various +benefits: + +- Reduced CPU/thread/process contention on a given Ethernet interface. +- Cache miss rate on completion is reduced, particularly for data + cache lines that hold the sk_buff structures. +- Increased process-level parallelism when handling received packets. +- Increased data cache hit rate, by steering kernel processing of + packets to the CPU, where the application thread consuming the + packet is running. +- In hardware interrupt re-direction. + +Interrupt Modes +=============== + +The driver assigns a single MSI-X vector per queue pair (for both Tx +and Rx directions). The driver assigns an additional dedicated MSI-X vector +for management (for ACQ and AENQ). + +Management interrupt registration is performed when the Linux kernel +probes the adapter, and it is de-registered when the adapter is +removed. I/O queue interrupt registration is performed when the Linux +interface of the adapter is opened, and it is de-registered when the +interface is closed. + +The management interrupt is named:: + + ena-mgmnt@pci:<PCI domain:bus:slot.function> + +and for each queue pair, an interrupt is named:: + + <interface name>-Tx-Rx-<queue index> + +The ENA device operates in auto-mask and auto-clear interrupt +modes. That is, once MSI-X is delivered to the host, its Cause bit is +automatically cleared and the interrupt is masked. The interrupt is +unmasked by the driver after NAPI processing is complete. + +Interrupt Moderation +==================== + +ENA driver and device can operate in conventional or adaptive interrupt +moderation mode. + +**In conventional mode** the driver instructs device to postpone interrupt +posting according to static interrupt delay value. The interrupt delay +value can be configured through `ethtool(8)`. The following `ethtool` +parameters are supported by the driver: ``tx-usecs``, ``rx-usecs`` + +**In adaptive interrupt** moderation mode the interrupt delay value is +updated by the driver dynamically and adjusted every NAPI cycle +according to the traffic nature. + +Adaptive coalescing can be switched on/off through `ethtool(8)`'s +:code:`adaptive_rx on|off` parameter. + +More information about Adaptive Interrupt Moderation (DIM) can be found in +Documentation/networking/net_dim.rst + +.. _`RX copybreak`: + +RX copybreak +============ +The rx_copybreak is initialized by default to ENA_DEFAULT_RX_COPYBREAK +and can be configured by the ETHTOOL_STUNABLE command of the +SIOCETHTOOL ioctl. + +Statistics +========== + +The user can obtain ENA device and driver statistics using `ethtool`. +The driver can collect regular or extended statistics (including +per-queue stats) from the device. + +In addition the driver logs the stats to syslog upon device reset. + +MTU +=== + +The driver supports an arbitrarily large MTU with a maximum that is +negotiated with the device. The driver configures MTU using the +SetFeature command (ENA_ADMIN_MTU property). The user can change MTU +via `ip(8)` and similar legacy tools. + +Stateless Offloads +================== + +The ENA driver supports: + +- IPv4 header checksum offload +- TCP/UDP over IPv4/IPv6 checksum offloads + +RSS +=== + +- The ENA device supports RSS that allows flexible Rx traffic + steering. +- Toeplitz and CRC32 hash functions are supported. +- Different combinations of L2/L3/L4 fields can be configured as + inputs for hash functions. +- The driver configures RSS settings using the AQ SetFeature command + (ENA_ADMIN_RSS_HASH_FUNCTION, ENA_ADMIN_RSS_HASH_INPUT and + ENA_ADMIN_RSS_INDIRECTION_TABLE_CONFIG properties). +- If the NETIF_F_RXHASH flag is set, the 32-bit result of the hash + function delivered in the Rx CQ descriptor is set in the received + SKB. +- The user can provide a hash key, hash function, and configure the + indirection table through `ethtool(8)`. + +DATA PATH +========= + +Tx +-- + +:code:`ena_start_xmit()` is called by the stack. This function does the following: + +- Maps data buffers (``skb->data`` and frags). +- Populates ``ena_buf`` for the push buffer (if the driver and device are + in push mode). +- Prepares ENA bufs for the remaining frags. +- Allocates a new request ID from the empty ``req_id`` ring. The request + ID is the index of the packet in the Tx info. This is used for + out-of-order Tx completions. +- Adds the packet to the proper place in the Tx ring. +- Calls :code:`ena_com_prepare_tx()`, an ENA communication layer that converts + the ``ena_bufs`` to ENA descriptors (and adds meta ENA descriptors as + needed). + + * This function also copies the ENA descriptors and the push buffer + to the Device memory space (if in push mode). + +- Writes a doorbell to the ENA device. +- When the ENA device finishes sending the packet, a completion + interrupt is raised. +- The interrupt handler schedules NAPI. +- The :code:`ena_clean_tx_irq()` function is called. This function handles the + completion descriptors generated by the ENA, with a single + completion descriptor per completed packet. + + * ``req_id`` is retrieved from the completion descriptor. The ``tx_info`` of + the packet is retrieved via the ``req_id``. The data buffers are + unmapped and ``req_id`` is returned to the empty ``req_id`` ring. + * The function stops when the completion descriptors are completed or + the budget is reached. + +Rx +-- + +- When a packet is received from the ENA device. +- The interrupt handler schedules NAPI. +- The :code:`ena_clean_rx_irq()` function is called. This function calls + :code:`ena_com_rx_pkt()`, an ENA communication layer function, which returns the + number of descriptors used for a new packet, and zero if + no new packet is found. +- :code:`ena_rx_skb()` checks packet length: + + * If the packet is small (len < rx_copybreak), the driver allocates + a SKB for the new packet, and copies the packet payload into the + SKB data buffer. + + - In this way the original data buffer is not passed to the stack + and is reused for future Rx packets. + + * Otherwise the function unmaps the Rx buffer, sets the first + descriptor as `skb`'s linear part and the other descriptors as the + `skb`'s frags. + +- The new SKB is updated with the necessary information (protocol, + checksum hw verify result, etc), and then passed to the network + stack, using the NAPI interface function :code:`napi_gro_receive()`. + +Dynamic RX Buffers (DRB) +------------------------ + +Each RX descriptor in the RX ring is a single memory page (which is either 4KB +or 16KB long depending on system's configurations). +To reduce the memory allocations required when dealing with a high rate of small +packets, the driver tries to reuse the remaining RX descriptor's space if more +than 2KB of this page remain unused. + +A simple example of this mechanism is the following sequence of events: + +:: + + 1. Driver allocates page-sized RX buffer and passes it to hardware + +----------------------+ + |4KB RX Buffer | + +----------------------+ + + 2. A 300Bytes packet is received on this buffer + + 3. The driver increases the ref count on this page and returns it back to + HW as an RX buffer of size 4KB - 300Bytes = 3796 Bytes + +----+--------------------+ + |****|3796 Bytes RX Buffer| + +----+--------------------+ + +This mechanism isn't used when an XDP program is loaded, or when the +RX packet is less than rx_copybreak bytes (in which case the packet is +copied out of the RX buffer into the linear part of a new skb allocated +for it and the RX buffer remains the same size, see `RX copybreak`_). diff --git a/Documentation/networking/device_drivers/ethernet/amd/pds_core.rst b/Documentation/networking/device_drivers/ethernet/amd/pds_core.rst new file mode 100644 index 0000000000..9e8a16c441 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/amd/pds_core.rst @@ -0,0 +1,139 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +======================================================== +Linux Driver for the AMD/Pensando(R) DSC adapter family +======================================================== + +Copyright(c) 2023 Advanced Micro Devices, Inc + +Identifying the Adapter +======================= + +To find if one or more AMD/Pensando PCI Core devices are installed on the +host, check for the PCI devices:: + + # lspci -d 1dd8:100c + b5:00.0 Processing accelerators: Pensando Systems Device 100c + b6:00.0 Processing accelerators: Pensando Systems Device 100c + +If such devices are listed as above, then the pds_core.ko driver should find +and configure them for use. There should be log entries in the kernel +messages such as these:: + + $ dmesg | grep pds_core + pds_core 0000:b5:00.0: 252.048 Gb/s available PCIe bandwidth (16.0 GT/s PCIe x16 link) + pds_core 0000:b5:00.0: FW: 1.60.0-73 + pds_core 0000:b6:00.0: 252.048 Gb/s available PCIe bandwidth (16.0 GT/s PCIe x16 link) + pds_core 0000:b6:00.0: FW: 1.60.0-73 + +Driver and firmware version information can be gathered with devlink:: + + $ devlink dev info pci/0000:b5:00.0 + pci/0000:b5:00.0: + driver pds_core + serial_number FLM18420073 + versions: + fixed: + asic.id 0x0 + asic.rev 0x0 + running: + fw 1.51.0-73 + stored: + fw.goldfw 1.15.9-C-22 + fw.mainfwa 1.60.0-73 + fw.mainfwb 1.60.0-57 + +Info versions +============= + +The ``pds_core`` driver reports the following versions + +.. list-table:: devlink info versions implemented + :widths: 5 5 90 + + * - Name + - Type + - Description + * - ``fw`` + - running + - Version of firmware running on the device + * - ``fw.goldfw`` + - stored + - Version of firmware stored in the goldfw slot + * - ``fw.mainfwa`` + - stored + - Version of firmware stored in the mainfwa slot + * - ``fw.mainfwb`` + - stored + - Version of firmware stored in the mainfwb slot + * - ``asic.id`` + - fixed + - The ASIC type for this device + * - ``asic.rev`` + - fixed + - The revision of the ASIC for this device + +Parameters +========== + +The ``pds_core`` driver implements the following generic +parameters for controlling the functionality to be made available +as auxiliary_bus devices. + +.. list-table:: Generic parameters implemented + :widths: 5 5 8 82 + + * - Name + - Mode + - Type + - Description + * - ``enable_vnet`` + - runtime + - Boolean + - Enables vDPA functionality through an auxiliary_bus device + +Firmware Management +=================== + +The ``flash`` command can update a the DSC firmware. The downloaded firmware +will be saved into either of firmware bank 1 or bank 2, whichever is not +currently in use, and that bank will used for the next boot:: + + # devlink dev flash pci/0000:b5:00.0 \ + file pensando/dsc_fw_1.63.0-22.tar + +Health Reporters +================ + +The driver supports a devlink health reporter for FW status:: + + # devlink health show pci/0000:2b:00.0 reporter fw + pci/0000:2b:00.0: + reporter fw + state healthy error 0 recover 0 + # devlink health diagnose pci/0000:2b:00.0 reporter fw + Status: healthy State: 1 Generation: 0 Recoveries: 0 + +Enabling the driver +=================== + +The driver is enabled via the standard kernel configuration system, +using the make command:: + + make oldconfig/menuconfig/etc. + +The driver is located in the menu structure at: + + -> Device Drivers + -> Network device support (NETDEVICES [=y]) + -> Ethernet driver support + -> AMD devices + -> AMD/Pensando Ethernet PDS_CORE Support + +Support +======= + +For general Linux networking support, please use the netdev mailing +list, which is monitored by AMD/Pensando personnel:: + + netdev@vger.kernel.org diff --git a/Documentation/networking/device_drivers/ethernet/amd/pds_vdpa.rst b/Documentation/networking/device_drivers/ethernet/amd/pds_vdpa.rst new file mode 100644 index 0000000000..587927d3de --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/amd/pds_vdpa.rst @@ -0,0 +1,85 @@ +.. SPDX-License-Identifier: GPL-2.0+ +.. note: can be edited and viewed with /usr/bin/formiko-vim + +========================================================== +PCI vDPA driver for the AMD/Pensando(R) DSC adapter family +========================================================== + +AMD/Pensando vDPA VF Device Driver + +Copyright(c) 2023 Advanced Micro Devices, Inc + +Overview +======== + +The ``pds_vdpa`` driver is an auxiliary bus driver that supplies +a vDPA device for use by the virtio network stack. It is used with +the Pensando Virtual Function devices that offer vDPA and virtio queue +services. It depends on the ``pds_core`` driver and hardware for the PF +and VF PCI handling as well as for device configuration services. + +Using the device +================ + +The ``pds_vdpa`` device is enabled via multiple configuration steps and +depends on the ``pds_core`` driver to create and enable SR-IOV Virtual +Function devices. After the VFs are enabled, we enable the vDPA service +in the ``pds_core`` device to create the auxiliary devices used by pds_vdpa. + +Example steps: + +.. code-block:: bash + + #!/bin/bash + + modprobe pds_core + modprobe vdpa + modprobe pds_vdpa + + PF_BDF=`ls /sys/module/pds_core/drivers/pci\:pds_core/*/sriov_numvfs | awk -F / '{print $7}'` + + # Enable vDPA VF auxiliary device(s) in the PF + devlink dev param set pci/$PF_BDF name enable_vnet cmode runtime value true + + # Create a VF for vDPA use + echo 1 > /sys/bus/pci/drivers/pds_core/$PF_BDF/sriov_numvfs + + # Find the vDPA services/devices available + PDS_VDPA_MGMT=`vdpa mgmtdev show | grep vDPA | head -1 | cut -d: -f1` + + # Create a vDPA device for use in virtio network configurations + vdpa dev add name vdpa1 mgmtdev $PDS_VDPA_MGMT mac 00:11:22:33:44:55 + + # Set up an ethernet interface on the vdpa device + modprobe virtio_vdpa + + + +Enabling the driver +=================== + +The driver is enabled via the standard kernel configuration system, +using the make command:: + + make oldconfig/menuconfig/etc. + +The driver is located in the menu structure at: + + -> Device Drivers + -> Network device support (NETDEVICES [=y]) + -> Ethernet driver support + -> Pensando devices + -> Pensando Ethernet PDS_VDPA Support + +Support +======= + +For general Linux networking support, please use the netdev mailing +list, which is monitored by Pensando personnel:: + + netdev@vger.kernel.org + +For more specific support needs, please use the Pensando driver support +email:: + + drivers@pensando.io diff --git a/Documentation/networking/device_drivers/ethernet/amd/pds_vfio_pci.rst b/Documentation/networking/device_drivers/ethernet/amd/pds_vfio_pci.rst new file mode 100644 index 0000000000..7a6bc848a2 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/amd/pds_vfio_pci.rst @@ -0,0 +1,79 @@ +.. SPDX-License-Identifier: GPL-2.0+ +.. note: can be edited and viewed with /usr/bin/formiko-vim + +========================================================== +PCI VFIO driver for the AMD/Pensando(R) DSC adapter family +========================================================== + +AMD/Pensando Linux VFIO PCI Device Driver +Copyright(c) 2023 Advanced Micro Devices, Inc. + +Overview +======== + +The ``pds-vfio-pci`` module is a PCI driver that supports Live Migration +capable Virtual Function (VF) devices in the DSC hardware. + +Using the device +================ + +The pds-vfio-pci device is enabled via multiple configuration steps and +depends on the ``pds_core`` driver to create and enable SR-IOV Virtual +Function devices. + +Shown below are the steps to bind the driver to a VF and also to the +associated auxiliary device created by the ``pds_core`` driver. This +example assumes the pds_core and pds-vfio-pci modules are already +loaded. + +.. code-block:: bash + :name: example-setup-script + + #!/bin/bash + + PF_BUS="0000:60" + PF_BDF="0000:60:00.0" + VF_BDF="0000:60:00.1" + + # Prevent non-vfio VF driver from probing the VF device + echo 0 > /sys/class/pci_bus/$PF_BUS/device/$PF_BDF/sriov_drivers_autoprobe + + # Create single VF for Live Migration via pds_core + echo 1 > /sys/bus/pci/drivers/pds_core/$PF_BDF/sriov_numvfs + + # Allow the VF to be bound to the pds-vfio-pci driver + echo "pds-vfio-pci" > /sys/class/pci_bus/$PF_BUS/device/$VF_BDF/driver_override + + # Bind the VF to the pds-vfio-pci driver + echo "$VF_BDF" > /sys/bus/pci/drivers/pds-vfio-pci/bind + +After performing the steps above, a file in /dev/vfio/<iommu_group> +should have been created. + + +Enabling the driver +=================== + +The driver is enabled via the standard kernel configuration system, +using the make command:: + + make oldconfig/menuconfig/etc. + +The driver is located in the menu structure at: + + -> Device Drivers + -> VFIO Non-Privileged userspace driver framework + -> VFIO support for PDS PCI devices + +Support +======= + +For general Linux networking support, please use the netdev mailing +list, which is monitored by Pensando personnel:: + + netdev@vger.kernel.org + +For more specific support needs, please use the Pensando driver support +email:: + + drivers@pensando.io diff --git a/Documentation/networking/device_drivers/ethernet/aquantia/atlantic.rst b/Documentation/networking/device_drivers/ethernet/aquantia/atlantic.rst new file mode 100644 index 0000000000..099280a261 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/aquantia/atlantic.rst @@ -0,0 +1,556 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> + +=============================== +Marvell(Aquantia) AQtion Driver +=============================== + +For the aQuantia Multi-Gigabit PCI Express Family of Ethernet Adapters + +.. Contents + + - Identifying Your Adapter + - Configuration + - Supported ethtool options + - Command Line Parameters + - Config file parameters + - Support + - License + +Identifying Your Adapter +======================== + +The driver in this release is compatible with AQC-100, AQC-107, AQC-108 +based ethernet adapters. + + +SFP+ Devices (for AQC-100 based adapters) +----------------------------------------- + +This release tested with passive Direct Attach Cables (DAC) and SFP+/LC +Optical Transceiver. + +Configuration +============= + +Viewing Link Messages +--------------------- + Link messages will not be displayed to the console if the distribution is + restricting system messages. In order to see network driver link messages on + your console, set dmesg to eight by entering the following:: + + dmesg -n 8 + + .. note:: + + This setting is not saved across reboots. + +Jumbo Frames +------------ + The driver supports Jumbo Frames for all adapters. Jumbo Frames support is + enabled by changing the MTU to a value larger than the default of 1500. + The maximum value for the MTU is 16000. Use the `ip` command to + increase the MTU size. For example:: + + ip link set mtu 16000 dev enp1s0 + +ethtool +------- + The driver utilizes the ethtool interface for driver configuration and + diagnostics, as well as displaying statistical information. The latest + ethtool version is required for this functionality. + +NAPI +---- + NAPI (Rx polling mode) is supported in the atlantic driver. + +Supported ethtool options +========================= + +Viewing adapter settings +------------------------ + + :: + + ethtool <ethX> + + Output example:: + + Settings for enp1s0: + Supported ports: [ TP ] + Supported link modes: 100baseT/Full + 1000baseT/Full + 10000baseT/Full + 2500baseT/Full + 5000baseT/Full + Supported pause frame use: Symmetric + Supports auto-negotiation: Yes + Supported FEC modes: Not reported + Advertised link modes: 100baseT/Full + 1000baseT/Full + 10000baseT/Full + 2500baseT/Full + 5000baseT/Full + Advertised pause frame use: Symmetric + Advertised auto-negotiation: Yes + Advertised FEC modes: Not reported + Speed: 10000Mb/s + Duplex: Full + Port: Twisted Pair + PHYAD: 0 + Transceiver: internal + Auto-negotiation: on + MDI-X: Unknown + Supports Wake-on: g + Wake-on: d + Link detected: yes + + + .. note:: + + AQrate speeds (2.5/5 Gb/s) will be displayed only with linux kernels > 4.10. + But you can still use these speeds:: + + ethtool -s eth0 autoneg off speed 2500 + +Viewing adapter information +--------------------------- + + :: + + ethtool -i <ethX> + + Output example:: + + driver: atlantic + version: 5.2.0-050200rc5-generic-kern + firmware-version: 3.1.78 + expansion-rom-version: + bus-info: 0000:01:00.0 + supports-statistics: yes + supports-test: no + supports-eeprom-access: no + supports-register-dump: yes + supports-priv-flags: no + + +Viewing Ethernet adapter statistics +----------------------------------- + + :: + + ethtool -S <ethX> + + Output example:: + + NIC statistics: + InPackets: 13238607 + InUCast: 13293852 + InMCast: 52 + InBCast: 3 + InErrors: 0 + OutPackets: 23703019 + OutUCast: 23704941 + OutMCast: 67 + OutBCast: 11 + InUCastOctects: 213182760 + OutUCastOctects: 22698443 + InMCastOctects: 6600 + OutMCastOctects: 8776 + InBCastOctects: 192 + OutBCastOctects: 704 + InOctects: 2131839552 + OutOctects: 226938073 + InPacketsDma: 95532300 + OutPacketsDma: 59503397 + InOctetsDma: 1137102462 + OutOctetsDma: 2394339518 + InDroppedDma: 0 + Queue[0] InPackets: 23567131 + Queue[0] OutPackets: 20070028 + Queue[0] InJumboPackets: 0 + Queue[0] InLroPackets: 0 + Queue[0] InErrors: 0 + Queue[1] InPackets: 45428967 + Queue[1] OutPackets: 11306178 + Queue[1] InJumboPackets: 0 + Queue[1] InLroPackets: 0 + Queue[1] InErrors: 0 + Queue[2] InPackets: 3187011 + Queue[2] OutPackets: 13080381 + Queue[2] InJumboPackets: 0 + Queue[2] InLroPackets: 0 + Queue[2] InErrors: 0 + Queue[3] InPackets: 23349136 + Queue[3] OutPackets: 15046810 + Queue[3] InJumboPackets: 0 + Queue[3] InLroPackets: 0 + Queue[3] InErrors: 0 + +Interrupt coalescing support +---------------------------- + + ITR mode, TX/RX coalescing timings could be viewed with:: + + ethtool -c <ethX> + + and changed with:: + + ethtool -C <ethX> tx-usecs <usecs> rx-usecs <usecs> + + To disable coalescing:: + + ethtool -C <ethX> tx-usecs 0 rx-usecs 0 tx-max-frames 1 tx-max-frames 1 + +Wake on LAN support +------------------- + + WOL support by magic packet:: + + ethtool -s <ethX> wol g + + To disable WOL:: + + ethtool -s <ethX> wol d + +Set and check the driver message level +-------------------------------------- + + Set message level + + :: + + ethtool -s <ethX> msglvl <level> + + Level values: + + ====== ============================= + 0x0001 general driver status. + 0x0002 hardware probing. + 0x0004 link state. + 0x0008 periodic status check. + 0x0010 interface being brought down. + 0x0020 interface being brought up. + 0x0040 receive error. + 0x0080 transmit error. + 0x0200 interrupt handling. + 0x0400 transmit completion. + 0x0800 receive completion. + 0x1000 packet contents. + 0x2000 hardware status. + 0x4000 Wake-on-LAN status. + ====== ============================= + + By default, the level of debugging messages is set 0x0001(general driver status). + + Check message level + + :: + + ethtool <ethX> | grep "Current message level" + + If you want to disable the output of messages:: + + ethtool -s <ethX> msglvl 0 + +RX flow rules (ntuple filters) +------------------------------ + + There are separate rules supported, that applies in that order: + + 1. 16 VLAN ID rules + 2. 16 L2 EtherType rules + 3. 8 L3/L4 5-Tuple rules + + + The driver utilizes the ethtool interface for configuring ntuple filters, + via ``ethtool -N <device> <filter>``. + + To enable or disable the RX flow rules:: + + ethtool -K ethX ntuple <on|off> + + When disabling ntuple filters, all the user programmed filters are + flushed from the driver cache and hardware. All needed filters must + be re-added when ntuple is re-enabled. + + Because of the fixed order of the rules, the location of filters is also fixed: + + - Locations 0 - 15 for VLAN ID filters + - Locations 16 - 31 for L2 EtherType filters + - Locations 32 - 39 for L3/L4 5-tuple filters (locations 32, 36 for IPv6) + + The L3/L4 5-tuple (protocol, source and destination IP address, source and + destination TCP/UDP/SCTP port) is compared against 8 filters. For IPv4, up to + 8 source and destination addresses can be matched. For IPv6, up to 2 pairs of + addresses can be supported. Source and destination ports are only compared for + TCP/UDP/SCTP packets. + + To add a filter that directs packet to queue 5, use + ``<-N|-U|--config-nfc|--config-ntuple>`` switch:: + + ethtool -N <ethX> flow-type udp4 src-ip 10.0.0.1 dst-ip 10.0.0.2 src-port 2000 dst-port 2001 action 5 <loc 32> + + - action is the queue number. + - loc is the rule number. + + For ``flow-type ip4|udp4|tcp4|sctp4|ip6|udp6|tcp6|sctp6`` you must set the loc + number within 32 - 39. + For ``flow-type ip4|udp4|tcp4|sctp4|ip6|udp6|tcp6|sctp6`` you can set 8 rules + for traffic IPv4 or you can set 2 rules for traffic IPv6. Loc number traffic + IPv6 is 32 and 36. + At the moment you can not use IPv4 and IPv6 filters at the same time. + + Example filter for IPv6 filter traffic:: + + sudo ethtool -N <ethX> flow-type tcp6 src-ip 2001:db8:0:f101::1 dst-ip 2001:db8:0:f101::2 action 1 loc 32 + sudo ethtool -N <ethX> flow-type ip6 src-ip 2001:db8:0:f101::2 dst-ip 2001:db8:0:f101::5 action -1 loc 36 + + Example filter for IPv4 filter traffic:: + + sudo ethtool -N <ethX> flow-type udp4 src-ip 10.0.0.4 dst-ip 10.0.0.7 src-port 2000 dst-port 2001 loc 32 + sudo ethtool -N <ethX> flow-type tcp4 src-ip 10.0.0.3 dst-ip 10.0.0.9 src-port 2000 dst-port 2001 loc 33 + sudo ethtool -N <ethX> flow-type ip4 src-ip 10.0.0.6 dst-ip 10.0.0.4 loc 34 + + If you set action -1, then all traffic corresponding to the filter will be discarded. + + The maximum value action is 31. + + + The VLAN filter (VLAN id) is compared against 16 filters. + VLAN id must be accompanied by mask 0xF000. That is to distinguish VLAN filter + from L2 Ethertype filter with UserPriority since both User Priority and VLAN ID + are passed in the same 'vlan' parameter. + + To add a filter that directs packets from VLAN 2001 to queue 5:: + + ethtool -N <ethX> flow-type ip4 vlan 2001 m 0xF000 action 1 loc 0 + + + L2 EtherType filters allows filter packet by EtherType field or both EtherType + and User Priority (PCP) field of 802.1Q. + UserPriority (vlan) parameter must be accompanied by mask 0x1FFF. That is to + distinguish VLAN filter from L2 Ethertype filter with UserPriority since both + User Priority and VLAN ID are passed in the same 'vlan' parameter. + + To add a filter that directs IP4 packess of priority 3 to queue 3:: + + ethtool -N <ethX> flow-type ether proto 0x800 vlan 0x600 m 0x1FFF action 3 loc 16 + + To see the list of filters currently present:: + + ethtool <-u|-n|--show-nfc|--show-ntuple> <ethX> + + Rules may be deleted from the table itself. This is done using:: + + sudo ethtool <-N|-U|--config-nfc|--config-ntuple> <ethX> delete <loc> + + - loc is the rule number to be deleted. + + Rx filters is an interface to load the filter table that funnels all flow + into queue 0 unless an alternative queue is specified using "action". In that + case, any flow that matches the filter criteria will be directed to the + appropriate queue. RX filters is supported on all kernels 2.6.30 and later. + +RSS for UDP +----------- + + Currently, NIC does not support RSS for fragmented IP packets, which leads to + incorrect working of RSS for fragmented UDP traffic. To disable RSS for UDP the + RX Flow L3/L4 rule may be used. + + Example:: + + ethtool -N eth0 flow-type udp4 action 0 loc 32 + +UDP GSO hardware offload +------------------------ + + UDP GSO allows to boost UDP tx rates by offloading UDP headers allocation + into hardware. A special userspace socket option is required for this, + could be validated with /kernel/tools/testing/selftests/net/:: + + udpgso_bench_tx -u -4 -D 10.0.1.1 -s 6300 -S 100 + + Will cause sending out of 100 byte sized UDP packets formed from single + 6300 bytes user buffer. + + UDP GSO is configured by:: + + ethtool -K eth0 tx-udp-segmentation on + +Private flags (testing) +----------------------- + + Atlantic driver supports private flags for hardware custom features:: + + $ ethtool --show-priv-flags ethX + + Private flags for ethX: + DMASystemLoopback : off + PKTSystemLoopback : off + DMANetworkLoopback : off + PHYInternalLoopback: off + PHYExternalLoopback: off + + Example:: + + $ ethtool --set-priv-flags ethX DMASystemLoopback on + + DMASystemLoopback: DMA Host loopback. + PKTSystemLoopback: Packet buffer host loopback. + DMANetworkLoopback: Network side loopback on DMA block. + PHYInternalLoopback: Internal loopback on Phy. + PHYExternalLoopback: External loopback on Phy (with loopback ethernet cable). + + +Command Line Parameters +======================= +The following command line parameters are available on atlantic driver: + +aq_itr -Interrupt throttling mode +--------------------------------- +Accepted values: 0, 1, 0xFFFF + +Default value: 0xFFFF + +====== ============================================================== +0 Disable interrupt throttling. +1 Enable interrupt throttling and use specified tx and rx rates. +0xFFFF Auto throttling mode. Driver will choose the best RX and TX + interrupt throttling settings based on link speed. +====== ============================================================== + +aq_itr_tx - TX interrupt throttle rate +-------------------------------------- + +Accepted values: 0 - 0x1FF + +Default value: 0 + +TX side throttling in microseconds. Adapter will setup maximum interrupt delay +to this value. Minimum interrupt delay will be a half of this value + +aq_itr_rx - RX interrupt throttle rate +-------------------------------------- + +Accepted values: 0 - 0x1FF + +Default value: 0 + +RX side throttling in microseconds. Adapter will setup maximum interrupt delay +to this value. Minimum interrupt delay will be a half of this value + +.. note:: + + ITR settings could be changed in runtime by ethtool -c means (see below) + +Config file parameters +====================== + +For some fine tuning and performance optimizations, +some parameters can be changed in the {source_dir}/aq_cfg.h file. + +AQ_CFG_RX_PAGEORDER +------------------- + +Default value: 0 + +RX page order override. That's a power of 2 number of RX pages allocated for +each descriptor. Received descriptor size is still limited by +AQ_CFG_RX_FRAME_MAX. + +Increasing pageorder makes page reuse better (actual on iommu enabled systems). + +AQ_CFG_RX_REFILL_THRES +---------------------- + +Default value: 32 + +RX refill threshold. RX path will not refill freed descriptors until the +specified number of free descriptors is observed. Larger values may help +better page reuse but may lead to packet drops as well. + +AQ_CFG_VECS_DEF +--------------- + +Number of queues + +Valid Range: 0 - 8 (up to AQ_CFG_VECS_MAX) + +Default value: 8 + +Notice this value will be capped by the number of cores available on the system. + +AQ_CFG_IS_RSS_DEF +----------------- + +Enable/disable Receive Side Scaling + +This feature allows the adapter to distribute receive processing +across multiple CPU-cores and to prevent from overloading a single CPU core. + +Valid values + +== ======== +0 disabled +1 enabled +== ======== + +Default value: 1 + +AQ_CFG_NUM_RSS_QUEUES_DEF +------------------------- + +Number of queues for Receive Side Scaling + +Valid Range: 0 - 8 (up to AQ_CFG_VECS_DEF) + +Default value: AQ_CFG_VECS_DEF + +AQ_CFG_IS_LRO_DEF +----------------- + +Enable/disable Large Receive Offload + +This offload enables the adapter to coalesce multiple TCP segments and indicate +them as a single coalesced unit to the OS networking subsystem. + +The system consumes less energy but it also introduces more latency in packets +processing. + +Valid values + +== ======== +0 disabled +1 enabled +== ======== + +Default value: 1 + +AQ_CFG_TX_CLEAN_BUDGET +---------------------- + +Maximum descriptors to cleanup on TX at once. + +Default value: 256 + +After the aq_cfg.h file changed the driver must be rebuilt to take effect. + +Support +======= + +If an issue is identified with the released source code on the supported +kernel with a supported adapter, email the specific information related +to the issue to aqn_support@marvell.com + +License +======= + +aQuantia Corporation Network Driver + +Copyright |copy| 2014 - 2019 aQuantia Corporation. + +This program is free software; you can redistribute it and/or modify it +under the terms and conditions of the GNU General Public License, +version 2, as published by the Free Software Foundation. diff --git a/Documentation/networking/device_drivers/ethernet/chelsio/cxgb.rst b/Documentation/networking/device_drivers/ethernet/chelsio/cxgb.rst new file mode 100644 index 0000000000..435dce5fa2 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/chelsio/cxgb.rst @@ -0,0 +1,393 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> + +============================================= +Chelsio N210 10Gb Ethernet Network Controller +============================================= + +Driver Release Notes for Linux + +Version 2.1.1 + +June 20, 2005 + +.. Contents + + INTRODUCTION + FEATURES + PERFORMANCE + DRIVER MESSAGES + KNOWN ISSUES + SUPPORT + + +Introduction +============ + + This document describes the Linux driver for Chelsio 10Gb Ethernet Network + Controller. This driver supports the Chelsio N210 NIC and is backward + compatible with the Chelsio N110 model 10Gb NICs. + + +Features +======== + +Adaptive Interrupts (adaptive-rx) +--------------------------------- + + This feature provides an adaptive algorithm that adjusts the interrupt + coalescing parameters, allowing the driver to dynamically adapt the latency + settings to achieve the highest performance during various types of network + load. + + The interface used to control this feature is ethtool. Please see the + ethtool manpage for additional usage information. + + By default, adaptive-rx is disabled. + To enable adaptive-rx:: + + ethtool -C <interface> adaptive-rx on + + To disable adaptive-rx, use ethtool:: + + ethtool -C <interface> adaptive-rx off + + After disabling adaptive-rx, the timer latency value will be set to 50us. + You may set the timer latency after disabling adaptive-rx:: + + ethtool -C <interface> rx-usecs <microseconds> + + An example to set the timer latency value to 100us on eth0:: + + ethtool -C eth0 rx-usecs 100 + + You may also provide a timer latency value while disabling adaptive-rx:: + + ethtool -C <interface> adaptive-rx off rx-usecs <microseconds> + + If adaptive-rx is disabled and a timer latency value is specified, the timer + will be set to the specified value until changed by the user or until + adaptive-rx is enabled. + + To view the status of the adaptive-rx and timer latency values:: + + ethtool -c <interface> + + +TCP Segmentation Offloading (TSO) Support +----------------------------------------- + + This feature, also known as "large send", enables a system's protocol stack + to offload portions of outbound TCP processing to a network interface card + thereby reducing system CPU utilization and enhancing performance. + + The interface used to control this feature is ethtool version 1.8 or higher. + Please see the ethtool manpage for additional usage information. + + By default, TSO is enabled. + To disable TSO:: + + ethtool -K <interface> tso off + + To enable TSO:: + + ethtool -K <interface> tso on + + To view the status of TSO:: + + ethtool -k <interface> + + +Performance +=========== + + The following information is provided as an example of how to change system + parameters for "performance tuning" an what value to use. You may or may not + want to change these system parameters, depending on your server/workstation + application. Doing so is not warranted in any way by Chelsio Communications, + and is done at "YOUR OWN RISK". Chelsio will not be held responsible for loss + of data or damage to equipment. + + Your distribution may have a different way of doing things, or you may prefer + a different method. These commands are shown only to provide an example of + what to do and are by no means definitive. + + Making any of the following system changes will only last until you reboot + your system. You may want to write a script that runs at boot-up which + includes the optimal settings for your system. + + Setting PCI Latency Timer:: + + setpci -d 1425:: + +* 0x0c.l=0x0000F800 + + Disabling TCP timestamp:: + + sysctl -w net.ipv4.tcp_timestamps=0 + + Disabling SACK:: + + sysctl -w net.ipv4.tcp_sack=0 + + Setting large number of incoming connection requests:: + + sysctl -w net.ipv4.tcp_max_syn_backlog=3000 + + Setting maximum receive socket buffer size:: + + sysctl -w net.core.rmem_max=1024000 + + Setting maximum send socket buffer size:: + + sysctl -w net.core.wmem_max=1024000 + + Set smp_affinity (on a multiprocessor system) to a single CPU:: + + echo 1 > /proc/irq/<interrupt_number>/smp_affinity + + Setting default receive socket buffer size:: + + sysctl -w net.core.rmem_default=524287 + + Setting default send socket buffer size:: + + sysctl -w net.core.wmem_default=524287 + + Setting maximum option memory buffers:: + + sysctl -w net.core.optmem_max=524287 + + Setting maximum backlog (# of unprocessed packets before kernel drops):: + + sysctl -w net.core.netdev_max_backlog=300000 + + Setting TCP read buffers (min/default/max):: + + sysctl -w net.ipv4.tcp_rmem="10000000 10000000 10000000" + + Setting TCP write buffers (min/pressure/max):: + + sysctl -w net.ipv4.tcp_wmem="10000000 10000000 10000000" + + Setting TCP buffer space (min/pressure/max):: + + sysctl -w net.ipv4.tcp_mem="10000000 10000000 10000000" + + TCP window size for single connections: + + The receive buffer (RX_WINDOW) size must be at least as large as the + Bandwidth-Delay Product of the communication link between the sender and + receiver. Due to the variations of RTT, you may want to increase the buffer + size up to 2 times the Bandwidth-Delay Product. Reference page 289 of + "TCP/IP Illustrated, Volume 1, The Protocols" by W. Richard Stevens. + + At 10Gb speeds, use the following formula:: + + RX_WINDOW >= 1.25MBytes * RTT(in milliseconds) + Example for RTT with 100us: RX_WINDOW = (1,250,000 * 0.1) = 125,000 + + RX_WINDOW sizes of 256KB - 512KB should be sufficient. + + Setting the min, max, and default receive buffer (RX_WINDOW) size:: + + sysctl -w net.ipv4.tcp_rmem="<min> <default> <max>" + + TCP window size for multiple connections: + The receive buffer (RX_WINDOW) size may be calculated the same as single + connections, but should be divided by the number of connections. The + smaller window prevents congestion and facilitates better pacing, + especially if/when MAC level flow control does not work well or when it is + not supported on the machine. Experimentation may be necessary to attain + the correct value. This method is provided as a starting point for the + correct receive buffer size. + + Setting the min, max, and default receive buffer (RX_WINDOW) size is + performed in the same manner as single connection. + + +Driver Messages +=============== + + The following messages are the most common messages logged by syslog. These + may be found in /var/log/messages. + + Driver up:: + + Chelsio Network Driver - version 2.1.1 + + NIC detected:: + + eth#: Chelsio N210 1x10GBaseX NIC (rev #), PCIX 133MHz/64-bit + + Link up:: + + eth#: link is up at 10 Gbps, full duplex + + Link down:: + + eth#: link is down + + +Known Issues +============ + + These issues have been identified during testing. The following information + is provided as a workaround to the problem. In some cases, this problem is + inherent to Linux or to a particular Linux Distribution and/or hardware + platform. + + 1. Large number of TCP retransmits on a multiprocessor (SMP) system. + + On a system with multiple CPUs, the interrupt (IRQ) for the network + controller may be bound to more than one CPU. This will cause TCP + retransmits if the packet data were to be split across different CPUs + and re-assembled in a different order than expected. + + To eliminate the TCP retransmits, set smp_affinity on the particular + interrupt to a single CPU. You can locate the interrupt (IRQ) used on + the N110/N210 by using ifconfig:: + + ifconfig <dev_name> | grep Interrupt + + Set the smp_affinity to a single CPU:: + + echo 1 > /proc/irq/<interrupt_number>/smp_affinity + + It is highly suggested that you do not run the irqbalance daemon on your + system, as this will change any smp_affinity setting you have applied. + The irqbalance daemon runs on a 10 second interval and binds interrupts + to the least loaded CPU determined by the daemon. To disable this daemon:: + + chkconfig --level 2345 irqbalance off + + By default, some Linux distributions enable the kernel feature, + irqbalance, which performs the same function as the daemon. To disable + this feature, add the following line to your bootloader:: + + noirqbalance + + Example using the Grub bootloader:: + + title Red Hat Enterprise Linux AS (2.4.21-27.ELsmp) + root (hd0,0) + kernel /vmlinuz-2.4.21-27.ELsmp ro root=/dev/hda3 noirqbalance + initrd /initrd-2.4.21-27.ELsmp.img + + 2. After running insmod, the driver is loaded and the incorrect network + interface is brought up without running ifup. + + When using 2.4.x kernels, including RHEL kernels, the Linux kernel + invokes a script named "hotplug". This script is primarily used to + automatically bring up USB devices when they are plugged in, however, + the script also attempts to automatically bring up a network interface + after loading the kernel module. The hotplug script does this by scanning + the ifcfg-eth# config files in /etc/sysconfig/network-scripts, looking + for HWADDR=<mac_address>. + + If the hotplug script does not find the HWADDRR within any of the + ifcfg-eth# files, it will bring up the device with the next available + interface name. If this interface is already configured for a different + network card, your new interface will have incorrect IP address and + network settings. + + To solve this issue, you can add the HWADDR=<mac_address> key to the + interface config file of your network controller. + + To disable this "hotplug" feature, you may add the driver (module name) + to the "blacklist" file located in /etc/hotplug. It has been noted that + this does not work for network devices because the net.agent script + does not use the blacklist file. Simply remove, or rename, the net.agent + script located in /etc/hotplug to disable this feature. + + 3. Transport Protocol (TP) hangs when running heavy multi-connection traffic + on an AMD Opteron system with HyperTransport PCI-X Tunnel chipset. + + If your AMD Opteron system uses the AMD-8131 HyperTransport PCI-X Tunnel + chipset, you may experience the "133-Mhz Mode Split Completion Data + Corruption" bug identified by AMD while using a 133Mhz PCI-X card on the + bus PCI-X bus. + + AMD states, "Under highly specific conditions, the AMD-8131 PCI-X Tunnel + can provide stale data via split completion cycles to a PCI-X card that + is operating at 133 Mhz", causing data corruption. + + AMD's provides three workarounds for this problem, however, Chelsio + recommends the first option for best performance with this bug: + + For 133Mhz secondary bus operation, limit the transaction length and + the number of outstanding transactions, via BIOS configuration + programming of the PCI-X card, to the following: + + Data Length (bytes): 1k + + Total allowed outstanding transactions: 2 + + Please refer to AMD 8131-HT/PCI-X Errata 26310 Rev 3.08 August 2004, + section 56, "133-MHz Mode Split Completion Data Corruption" for more + details with this bug and workarounds suggested by AMD. + + It may be possible to work outside AMD's recommended PCI-X settings, try + increasing the Data Length to 2k bytes for increased performance. If you + have issues with these settings, please revert to the "safe" settings + and duplicate the problem before submitting a bug or asking for support. + + .. note:: + + The default setting on most systems is 8 outstanding transactions + and 2k bytes data length. + + 4. On multiprocessor systems, it has been noted that an application which + is handling 10Gb networking can switch between CPUs causing degraded + and/or unstable performance. + + If running on an SMP system and taking performance measurements, it + is suggested you either run the latest netperf-2.4.0+ or use a binding + tool such as Tim Hockin's procstate utilities (runon) + <http://www.hockin.org/~thockin/procstate/>. + + Binding netserver and netperf (or other applications) to particular + CPUs will have a significant difference in performance measurements. + You may need to experiment which CPU to bind the application to in + order to achieve the best performance for your system. + + If you are developing an application designed for 10Gb networking, + please keep in mind you may want to look at kernel functions + sched_setaffinity & sched_getaffinity to bind your application. + + If you are just running user-space applications such as ftp, telnet, + etc., you may want to try the runon tool provided by Tim Hockin's + procstate utility. You could also try binding the interface to a + particular CPU: runon 0 ifup eth0 + + +Support +======= + + If you have problems with the software or hardware, please contact our + customer support team via email at support@chelsio.com or check our website + at http://www.chelsio.com + +------------------------------------------------------------------------------- + +:: + + Chelsio Communications + 370 San Aleso Ave. + Suite 100 + Sunnyvale, CA 94085 + http://www.chelsio.com + +This program is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License, version 2, as +published by the Free Software Foundation. + +You should have received a copy of the GNU General Public License along +with this program; if not, write to the Free Software Foundation, Inc., +59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + +THIS SOFTWARE IS PROVIDED ``AS IS`` AND WITHOUT ANY EXPRESS OR IMPLIED +WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF +MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. + +Copyright |copy| 2003-2005 Chelsio Communications. All rights reserved. diff --git a/Documentation/networking/device_drivers/ethernet/cirrus/cs89x0.rst b/Documentation/networking/device_drivers/ethernet/cirrus/cs89x0.rst new file mode 100644 index 0000000000..e5c283940a --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/cirrus/cs89x0.rst @@ -0,0 +1,647 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================================================ +Cirrus Logic LAN CS8900/CS8920 Ethernet Adapters +================================================ + +.. note:: + + This document was contributed by Cirrus Logic for kernel 2.2.5. This version + has been updated for 2.3.48 by Andrew Morton. + + Still, this is too outdated! A major cleanup is needed here. + +Cirrus make a copy of this driver available at their website, as +described below. In general, you should use the driver version which +comes with your Linux distribution. + + +Linux Network Interface Driver ver. 2.00 <kernel 2.3.48> + + +.. TABLE OF CONTENTS + + 1.0 CIRRUS LOGIC LAN CS8900/CS8920 ETHERNET ADAPTERS + 1.1 Product Overview + 1.2 Driver Description + 1.2.1 Driver Name + 1.2.2 File in the Driver Package + 1.3 System Requirements + 1.4 Licensing Information + + 2.0 ADAPTER INSTALLATION and CONFIGURATION + 2.1 CS8900-based Adapter Configuration + 2.2 CS8920-based Adapter Configuration + + 3.0 LOADING THE DRIVER AS A MODULE + + 4.0 COMPILING THE DRIVER + 4.1 Compiling the Driver as a Loadable Module + 4.2 Compiling the driver to support memory mode + 4.3 Compiling the driver to support Rx DMA + + 5.0 TESTING AND TROUBLESHOOTING + 5.1 Known Defects and Limitations + 5.2 Testing the Adapter + 5.2.1 Diagnostic Self-Test + 5.2.2 Diagnostic Network Test + 5.3 Using the Adapter's LEDs + 5.4 Resolving I/O Conflicts + + 6.0 TECHNICAL SUPPORT + 6.1 Contacting Cirrus Logic's Technical Support + 6.2 Information Required Before Contacting Technical Support + 6.3 Obtaining the Latest Driver Version + 6.4 Current maintainer + 6.5 Kernel boot parameters + + +1. Cirrus Logic LAN CS8900/CS8920 Ethernet Adapters +=================================================== + + +1.1. Product Overview +===================== + +The CS8900-based ISA Ethernet Adapters from Cirrus Logic follow +IEEE 802.3 standards and support half or full-duplex operation in ISA bus +computers on 10 Mbps Ethernet networks. The adapters are designed for operation +in 16-bit ISA or EISA bus expansion slots and are available in +10BaseT-only or 3-media configurations (10BaseT, 10Base2, and AUI for 10Base-5 +or fiber networks). + +CS8920-based adapters are similar to the CS8900-based adapter with additional +features for Plug and Play (PnP) support and Wakeup Frame recognition. As +such, the configuration procedures differ somewhat between the two types of +adapters. Refer to the "Adapter Configuration" section for details on +configuring both types of adapters. + + +1.2. Driver Description +======================= + +The CS8900/CS8920 Ethernet Adapter driver for Linux supports the Linux +v2.3.48 or greater kernel. It can be compiled directly into the kernel +or loaded at run-time as a device driver module. + +1.2.1 Driver Name: cs89x0 + +1.2.2 Files in the Driver Archive: + +The files in the driver at Cirrus' website include: + + =================== ==================================================== + readme.txt this file + build batch file to compile cs89x0.c. + cs89x0.c driver C code + cs89x0.h driver header file + cs89x0.o pre-compiled module (for v2.2.5 kernel) + config/Config.in sample file to include cs89x0 driver in the kernel. + config/Makefile sample file to include cs89x0 driver in the kernel. + config/Space.c sample file to include cs89x0 driver in the kernel. + =================== ==================================================== + + + +1.3. System Requirements +------------------------ + +The following hardware is required: + + * Cirrus Logic LAN (CS8900/20-based) Ethernet ISA Adapter + + * IBM or IBM-compatible PC with: + * An 80386 or higher processor + * 16 bytes of contiguous IO space available between 210h - 370h + * One available IRQ (5,10,11,or 12 for the CS8900, 3-7,9-15 for CS8920). + + * Appropriate cable (and connector for AUI, 10BASE-2) for your network + topology. + +The following software is required: + +* LINUX kernel version 2.3.48 or higher + + * CS8900/20 Setup Utility (DOS-based) + + * LINUX kernel sources for your kernel (if compiling into kernel) + + * GNU Toolkit (gcc and make) v2.6 or above (if compiling into kernel + or a module) + + + +1.4. Licensing Information +-------------------------- + +This program is free software; you can redistribute it and/or modify it under +the terms of the GNU General Public License as published by the Free Software +Foundation, version 1. + +This program is distributed in the hope that it will be useful, but WITHOUT +ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or +FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for +more details. + +For a full copy of the GNU General Public License, write to the Free Software +Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + + + +2. Adapter Installation and Configuration +========================================= + +Both the CS8900 and CS8920-based adapters can be configured using parameters +stored in an on-board EEPROM. You must use the DOS-based CS8900/20 Setup +Utility if you want to change the adapter's configuration in EEPROM. + +When loading the driver as a module, you can specify many of the adapter's +configuration parameters on the command-line to override the EEPROM's settings +or for interface configuration when an EEPROM is not used. (CS8920-based +adapters must use an EEPROM.) See Section 3.0 LOADING THE DRIVER AS A MODULE. + +Since the CS8900/20 Setup Utility is a DOS-based application, you must install +and configure the adapter in a DOS-based system using the CS8900/20 Setup +Utility before installation in the target LINUX system. (Not required if +installing a CS8900-based adapter and the default configuration is acceptable.) + + +2.1. CS8900-based Adapter Configuration +--------------------------------------- + +CS8900-based adapters shipped from Cirrus Logic have been configured +with the following "default" settings:: + + Operation Mode: Memory Mode + IRQ: 10 + Base I/O Address: 300 + Memory Base Address: D0000 + Optimization: DOS Client + Transmission Mode: Half-duplex + BootProm: None + Media Type: Autodetect (3-media cards) or + 10BASE-T (10BASE-T only adapter) + +You should only change the default configuration settings if conflicts with +another adapter exists. To change the adapter's configuration, run the +CS8900/20 Setup Utility. + + +2.2. CS8920-based Adapter Configuration +--------------------------------------- + +CS8920-based adapters are shipped from Cirrus Logic configured as Plug +and Play (PnP) enabled. However, since the cs89x0 driver does NOT +support PnP, you must install the CS8920 adapter in a DOS-based PC and +run the CS8900/20 Setup Utility to disable PnP and configure the +adapter before installation in the target Linux system. Failure to do +this will leave the adapter inactive and the driver will be unable to +communicate with the adapter. + +:: + + **************************************************************** + * CS8920-BASED ADAPTERS: * + * * + * CS8920-BASED ADAPTERS ARE PLUG and PLAY ENABLED BY DEFAULT. * + * THE CS89X0 DRIVER DOES NOT SUPPORT PnP. THEREFORE, YOU MUST * + * RUN THE CS8900/20 SETUP UTILITY TO DISABLE PnP SUPPORT AND * + * TO ACTIVATE THE ADAPTER. * + **************************************************************** + + + + +3. Loading the Driver as a Module +================================= + +If the driver is compiled as a loadable module, you can load the driver module +with the 'modprobe' command. Many of the adapter's configuration parameters can +be specified as command-line arguments to the load command. This facility +provides a means to override the EEPROM's settings or for interface +configuration when an EEPROM is not used. + +Example:: + + insmod cs89x0.o io=0x200 irq=0xA media=aui + +This example loads the module and configures the adapter to use an IO port base +address of 200h, interrupt 10, and use the AUI media connection. The following +configuration options are available on the command line:: + + io=### - specify IO address (200h-360h) + irq=## - specify interrupt level + use_dma=1 - Enable DMA + dma=# - specify dma channel (Driver is compiled to support + Rx DMA only) + dmasize=# (16 or 64) - DMA size 16K or 64K. Default value is set to 16. + media=rj45 - specify media type + or media=bnc + or media=aui + or media=auto + duplex=full - specify forced half/full/autonegotiate duplex + or duplex=half + or duplex=auto + debug=# - debug level (only available if the driver was compiled + for debugging) + +**Notes:** + +a) If an EEPROM is present, any specified command-line parameter + will override the corresponding configuration value stored in + EEPROM. + +b) The "io" parameter must be specified on the command-line. + +c) The driver's hardware probe routine is designed to avoid + writing to I/O space until it knows that there is a cs89x0 + card at the written addresses. This could cause problems + with device probing. To avoid this behaviour, add one + to the ``io=`` module parameter. This doesn't actually change + the I/O address, but it is a flag to tell the driver + to partially initialise the hardware before trying to + identify the card. This could be dangerous if you are + not sure that there is a cs89x0 card at the provided address. + + For example, to scan for an adapter located at IO base 0x300, + specify an IO address of 0x301. + +d) The "duplex=auto" parameter is only supported for the CS8920. + +e) The minimum command-line configuration required if an EEPROM is + not present is: + + io + irq + media type (no autodetect) + +f) The following additional parameters are CS89XX defaults (values + used with no EEPROM or command-line argument). + + * DMA Burst = enabled + * IOCHRDY Enabled = enabled + * UseSA = enabled + * CS8900 defaults to half-duplex if not specified on command-line + * CS8920 defaults to autoneg if not specified on command-line + * Use reset defaults for other config parameters + * dma_mode = 0 + +g) You can use ifconfig to set the adapter's Ethernet address. + +h) Many Linux distributions use the 'modprobe' command to load + modules. This program uses the '/etc/conf.modules' file to + determine configuration information which is passed to a driver + module when it is loaded. All the configuration options which are + described above may be placed within /etc/conf.modules. + + For example:: + + > cat /etc/conf.modules + ... + alias eth0 cs89x0 + options cs89x0 io=0x0200 dma=5 use_dma=1 + ... + + In this example we are telling the module system that the + ethernet driver for this machine should use the cs89x0 driver. We + are asking 'modprobe' to pass the 'io', 'dma' and 'use_dma' + arguments to the driver when it is loaded. + +i) Cirrus recommend that the cs89x0 use the ISA DMA channels 5, 6 or + 7. You will probably find that other DMA channels will not work. + +j) The cs89x0 supports DMA for receiving only. DMA mode is + significantly more efficient. Flooding a 400 MHz Celeron machine + with large ping packets consumes 82% of its CPU capacity in non-DMA + mode. With DMA this is reduced to 45%. + +k) If your Linux kernel was compiled with inbuilt plug-and-play + support you will be able to find information about the cs89x0 card + with the command:: + + cat /proc/isapnp + +l) If during DMA operation you find erratic behavior or network data + corruption you should use your PC's BIOS to slow the EISA bus clock. + +m) If the cs89x0 driver is compiled directly into the kernel + (non-modular) then its I/O address is automatically determined by + ISA bus probing. The IRQ number, media options, etc are determined + from the card's EEPROM. + +n) If the cs89x0 driver is compiled directly into the kernel, DMA + mode may be selected by providing the kernel with a boot option + 'cs89x0_dma=N' where 'N' is the desired DMA channel number (5, 6 or 7). + + Kernel boot options may be provided on the LILO command line:: + + LILO boot: linux cs89x0_dma=5 + + or they may be placed in /etc/lilo.conf:: + + image=/boot/bzImage-2.3.48 + append="cs89x0_dma=5" + label=linux + root=/dev/hda5 + read-only + + The DMA Rx buffer size is hardwired to 16 kbytes in this mode. + (64k mode is not available). + + +4. Compiling the Driver +======================= + +The cs89x0 driver can be compiled directly into the kernel or compiled into +a loadable device driver module. + +Just use the standard way to configure the driver and compile the Kernel. + + +4.1. Compiling the Driver to Support Rx DMA +------------------------------------------- + +The compile-time optionality for DMA was removed in the 2.3 kernel +series. DMA support is now unconditionally part of the driver. It is +enabled by the 'use_dma=1' module option. + + +5. Testing and Troubleshooting +============================== + +5.1. Known Defects and Limitations +---------------------------------- + +Refer to the RELEASE.TXT file distributed as part of this archive for a list of +known defects, driver limitations, and work arounds. + + +5.2. Testing the Adapter +------------------------ + +Once the adapter has been installed and configured, the diagnostic option of +the CS8900/20 Setup Utility can be used to test the functionality of the +adapter and its network connection. Use the diagnostics 'Self Test' option to +test the functionality of the adapter with the hardware configuration you have +assigned. You can use the diagnostics 'Network Test' to test the ability of the +adapter to communicate across the Ethernet with another PC equipped with a +CS8900/20-based adapter card (it must also be running the CS8900/20 Setup +Utility). + +.. note:: + + The Setup Utility's diagnostics are designed to run in a + DOS-only operating system environment. DO NOT run the diagnostics + from a DOS or command prompt session under Windows 95, Windows NT, + OS/2, or other operating system. + +To run the diagnostics tests on the CS8900/20 adapter: + + 1. Boot DOS on the PC and start the CS8900/20 Setup Utility. + + 2. The adapter's current configuration is displayed. Hit the ENTER key to + get to the main menu. + + 4. Select 'Diagnostics' (ALT-G) from the main menu. + * Select 'Self-Test' to test the adapter's basic functionality. + * Select 'Network Test' to test the network connection and cabling. + + +5.2.1. Diagnostic Self-test +^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The diagnostic self-test checks the adapter's basic functionality as well as +its ability to communicate across the ISA bus based on the system resources +assigned during hardware configuration. The following tests are performed: + + * IO Register Read/Write Test + + The IO Register Read/Write test insures that the CS8900/20 can be + accessed in IO mode, and that the IO base address is correct. + + * Shared Memory Test + + The Shared Memory test insures the CS8900/20 can be accessed in memory + mode and that the range of memory addresses assigned does not conflict + with other devices in the system. + + * Interrupt Test + + The Interrupt test insures there are no conflicts with the assigned IRQ + signal. + + * EEPROM Test + + The EEPROM test insures the EEPROM can be read. + + * Chip RAM Test + + The Chip RAM test insures the 4K of memory internal to the CS8900/20 is + working properly. + + * Internal Loop-back Test + + The Internal Loop Back test insures the adapter's transmitter and + receiver are operating properly. If this test fails, make sure the + adapter's cable is connected to the network (check for LED activity for + example). + + * Boot PROM Test + + The Boot PROM test insures the Boot PROM is present, and can be read. + Failure indicates the Boot PROM was not successfully read due to a + hardware problem or due to a conflicts on the Boot PROM address + assignment. (Test only applies if the adapter is configured to use the + Boot PROM option.) + +Failure of a test item indicates a possible system resource conflict with +another device on the ISA bus. In this case, you should use the Manual Setup +option to reconfigure the adapter by selecting a different value for the system +resource that failed. + + +5.2.2. Diagnostic Network Test +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The Diagnostic Network Test verifies a working network connection by +transferring data between two CS8900/20 adapters installed in different PCs +on the same network. (Note: the diagnostic network test should not be run +between two nodes across a router.) + +This test requires that each of the two PCs have a CS8900/20-based adapter +installed and have the CS8900/20 Setup Utility running. The first PC is +configured as a Responder and the other PC is configured as an Initiator. +Once the Initiator is started, it sends data frames to the Responder which +returns the frames to the Initiator. + +The total number of frames received and transmitted are displayed on the +Initiator's display, along with a count of the number of frames received and +transmitted OK or in error. The test can be terminated anytime by the user at +either PC. + +To setup the Diagnostic Network Test: + + 1. Select a PC with a CS8900/20-based adapter and a known working network + connection to act as the Responder. Run the CS8900/20 Setup Utility + and select 'Diagnostics -> Network Test -> Responder' from the main + menu. Hit ENTER to start the Responder. + + 2. Return to the PC with the CS8900/20-based adapter you want to test and + start the CS8900/20 Setup Utility. + + 3. From the main menu, Select 'Diagnostic -> Network Test -> Initiator'. + Hit ENTER to start the test. + +You may stop the test on the Initiator at any time while allowing the Responder +to continue running. In this manner, you can move to additional PCs and test +them by starting the Initiator on another PC without having to stop/start the +Responder. + + + +5.3. Using the Adapter's LEDs +----------------------------- + +The 2 and 3-media adapters have two LEDs visible on the back end of the board +located near the 10Base-T connector. + +Link Integrity LED: A "steady" ON of the green LED indicates a valid 10Base-T +connection. (Only applies to 10Base-T. The green LED has no significance for +a 10Base-2 or AUI connection.) + +TX/RX LED: The yellow LED lights briefly each time the adapter transmits or +receives data. (The yellow LED will appear to "flicker" on a typical network.) + + +5.4. Resolving I/O Conflicts +---------------------------- + +An IO conflict occurs when two or more adapter use the same ISA resource (IO +address, memory address or IRQ). You can usually detect an IO conflict in one +of four ways after installing and or configuring the CS8900/20-based adapter: + + 1. The system does not boot properly (or at all). + + 2. The driver cannot communicate with the adapter, reporting an "Adapter + not found" error message. + + 3. You cannot connect to the network or the driver will not load. + + 4. If you have configured the adapter to run in memory mode but the driver + reports it is using IO mode when loading, this is an indication of a + memory address conflict. + +If an IO conflict occurs, run the CS8900/20 Setup Utility and perform a +diagnostic self-test. Normally, the ISA resource in conflict will fail the +self-test. If so, reconfigure the adapter selecting another choice for the +resource in conflict. Run the diagnostics again to check for further IO +conflicts. + +In some cases, such as when the PC will not boot, it may be necessary to remove +the adapter and reconfigure it by installing it in another PC to run the +CS8900/20 Setup Utility. Once reinstalled in the target system, run the +diagnostics self-test to ensure the new configuration is free of conflicts +before loading the driver again. + +When manually configuring the adapter, keep in mind the typical ISA system +resource usage as indicated in the tables below. + +:: + + I/O Address Device IRQ Device + ----------- -------- --- -------- + 200-20F Game I/O adapter 3 COM2, Bus Mouse + 230-23F Bus Mouse 4 COM1 + 270-27F LPT3: third parallel port 5 LPT2 + 2F0-2FF COM2: second serial port 6 Floppy Disk controller + 320-32F Fixed disk controller 7 LPT1 + 8 Real-time Clock + 9 EGA/VGA display adapter + 12 Mouse (PS/2) + Memory Address Device 13 Math Coprocessor + -------------- --------------------- 14 Hard Disk controller + A000-BFFF EGA Graphics Adapter + A000-C7FF VGA Graphics Adapter + B000-BFFF Mono Graphics Adapter + B800-BFFF Color Graphics Adapter + E000-FFFF AT BIOS + + + + +6. Technical Support +==================== + +6.1. Contacting Cirrus Logic's Technical Support +------------------------------------------------ + +Cirrus Logic's CS89XX Technical Application Support can be reached at:: + + Telephone :(800) 888-5016 (from inside U.S. and Canada) + :(512) 442-7555 (from outside the U.S. and Canada) + Fax :(512) 912-3871 + Email :ethernet@crystal.cirrus.com + WWW :http://www.cirrus.com + + +6.2. Information Required before Contacting Technical Support +------------------------------------------------------------- + +Before contacting Cirrus Logic for technical support, be prepared to provide as +Much of the following information as possible. + +1.) Adapter type (CRD8900, CDB8900, CDB8920, etc.) + +2.) Adapter configuration + + * IO Base, Memory Base, IO or memory mode enabled, IRQ, DMA channel + * Plug and Play enabled/disabled (CS8920-based adapters only) + * Configured for media auto-detect or specific media type (which type). + +3.) PC System's Configuration + + * Plug and Play system (yes/no) + * BIOS (make and version) + * System make and model + * CPU (type and speed) + * System RAM + * SCSI Adapter + +4.) Software + + * CS89XX driver and version + * Your network operating system and version + * Your system's OS version + * Version of all protocol support files + +5.) Any Error Message displayed. + + + +6.3 Obtaining the Latest Driver Version +--------------------------------------- + +You can obtain the latest CS89XX drivers and support software from Cirrus Logic's +Web site. You can also contact Cirrus Logic's Technical Support (email: +ethernet@crystal.cirrus.com) and request that you be registered for automatic +software-update notification. + +Cirrus Logic maintains a web page at http://www.cirrus.com with the +latest drivers and technical publications. + + +6.4. Current maintainer +----------------------- + +In February 2000 the maintenance of this driver was assumed by Andrew +Morton. + +6.5 Kernel module parameters +---------------------------- + +For use in embedded environments with no cs89x0 EEPROM, the kernel boot +parameter ``cs89x0_media=`` has been implemented. Usage is:: + + cs89x0_media=rj45 or + cs89x0_media=aui or + cs89x0_media=bnc diff --git a/Documentation/networking/device_drivers/ethernet/davicom/dm9000.rst b/Documentation/networking/device_drivers/ethernet/davicom/dm9000.rst new file mode 100644 index 0000000000..14eb0a4d4e --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/davicom/dm9000.rst @@ -0,0 +1,171 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================== +DM9000 Network driver +===================== + +Copyright 2008 Simtec Electronics, + + Ben Dooks <ben@simtec.co.uk> <ben-linux@fluff.org> + + +Introduction +------------ + +This file describes how to use the DM9000 platform-device based network driver +that is contained in the files drivers/net/dm9000.c and drivers/net/dm9000.h. + +The driver supports three DM9000 variants, the DM9000E which is the first chip +supported as well as the newer DM9000A and DM9000B devices. It is currently +maintained and tested by Ben Dooks, who should be CC: to any patches for this +driver. + + +Defining the platform device +---------------------------- + +The minimum set of resources attached to the platform device are as follows: + + 1) The physical address of the address register + 2) The physical address of the data register + 3) The IRQ line the device's interrupt pin is connected to. + +These resources should be specified in that order, as the ordering of the +two address regions is important (the driver expects these to be address +and then data). + +An example from arch/arm/mach-s3c/mach-bast.c is:: + + static struct resource bast_dm9k_resource[] = { + [0] = { + .start = S3C2410_CS5 + BAST_PA_DM9000, + .end = S3C2410_CS5 + BAST_PA_DM9000 + 3, + .flags = IORESOURCE_MEM, + }, + [1] = { + .start = S3C2410_CS5 + BAST_PA_DM9000 + 0x40, + .end = S3C2410_CS5 + BAST_PA_DM9000 + 0x40 + 0x3f, + .flags = IORESOURCE_MEM, + }, + [2] = { + .start = IRQ_DM9000, + .end = IRQ_DM9000, + .flags = IORESOURCE_IRQ | IORESOURCE_IRQ_HIGHLEVEL, + } + }; + + static struct platform_device bast_device_dm9k = { + .name = "dm9000", + .id = 0, + .num_resources = ARRAY_SIZE(bast_dm9k_resource), + .resource = bast_dm9k_resource, + }; + +Note the setting of the IRQ trigger flag in bast_dm9k_resource[2].flags, +as this will generate a warning if it is not present. The trigger from +the flags field will be passed to request_irq() when registering the IRQ +handler to ensure that the IRQ is setup correctly. + +This shows a typical platform device, without the optional configuration +platform data supplied. The next example uses the same resources, but adds +the optional platform data to pass extra configuration data:: + + static struct dm9000_plat_data bast_dm9k_platdata = { + .flags = DM9000_PLATF_16BITONLY, + }; + + static struct platform_device bast_device_dm9k = { + .name = "dm9000", + .id = 0, + .num_resources = ARRAY_SIZE(bast_dm9k_resource), + .resource = bast_dm9k_resource, + .dev = { + .platform_data = &bast_dm9k_platdata, + } + }; + +The platform data is defined in include/linux/dm9000.h and described below. + + +Platform data +------------- + +Extra platform data for the DM9000 can describe the IO bus width to the +device, whether or not an external PHY is attached to the device and +the availability of an external configuration EEPROM. + +The flags for the platform data .flags field are as follows: + +DM9000_PLATF_8BITONLY + + The IO should be done with 8bit operations. + +DM9000_PLATF_16BITONLY + + The IO should be done with 16bit operations. + +DM9000_PLATF_32BITONLY + + The IO should be done with 32bit operations. + +DM9000_PLATF_EXT_PHY + + The chip is connected to an external PHY. + +DM9000_PLATF_NO_EEPROM + + This can be used to signify that the board does not have an + EEPROM, or that the EEPROM should be hidden from the user. + +DM9000_PLATF_SIMPLE_PHY + + Switch to using the simpler PHY polling method which does not + try and read the MII PHY state regularly. This is only available + when using the internal PHY. See the section on link state polling + for more information. + + The config symbol DM9000_FORCE_SIMPLE_PHY_POLL, Kconfig entry + "Force simple NSR based PHY polling" allows this flag to be + forced on at build time. + + +PHY Link state polling +---------------------- + +The driver keeps track of the link state and informs the network core +about link (carrier) availability. This is managed by several methods +depending on the version of the chip and on which PHY is being used. + +For the internal PHY, the original (and currently default) method is +to read the MII state, either when the status changes if we have the +necessary interrupt support in the chip or every two seconds via a +periodic timer. + +To reduce the overhead for the internal PHY, there is now the option +of using the DM9000_FORCE_SIMPLE_PHY_POLL config, or DM9000_PLATF_SIMPLE_PHY +platform data option to read the summary information without the +expensive MII accesses. This method is faster, but does not print +as much information. + +When using an external PHY, the driver currently has to poll the MII +link status as there is no method for getting an interrupt on link change. + + +DM9000A / DM9000B +----------------- + +These chips are functionally similar to the DM9000E and are supported easily +by the same driver. The features are: + + 1) Interrupt on internal PHY state change. This means that the periodic + polling of the PHY status may be disabled on these devices when using + the internal PHY. + + 2) TCP/UDP checksum offloading, which the driver does not currently support. + + +ethtool +------- + +The driver supports the ethtool interface for access to the driver +state information, the PHY state and the EEPROM. diff --git a/Documentation/networking/device_drivers/ethernet/dec/dmfe.rst b/Documentation/networking/device_drivers/ethernet/dec/dmfe.rst new file mode 100644 index 0000000000..c4cf809cad --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/dec/dmfe.rst @@ -0,0 +1,71 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================================================== +Davicom DM9102(A)/DM9132/DM9801 fast ethernet driver for Linux +============================================================== + +Note: This driver doesn't have a maintainer. + + +This program is free software; you can redistribute it and/or +modify it under the terms of the GNU General Public License +as published by the Free Software Foundation; either version 2 +of the License, or (at your option) any later version. + +This program is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + + +This driver provides kernel support for Davicom DM9102(A)/DM9132/DM9801 ethernet cards ( CNET +10/100 ethernet cards uses Davicom chipset too, so this driver supports CNET cards too ).If you +didn't compile this driver as a module, it will automatically load itself on boot and print a +line similar to:: + + dmfe: Davicom DM9xxx net driver, version 1.36.4 (2002-01-17) + +If you compiled this driver as a module, you have to load it on boot.You can load it with command:: + + insmod dmfe + +This way it will autodetect the device mode.This is the suggested way to load the module.Or you can pass +a mode= setting to module while loading, like:: + + insmod dmfe mode=0 # Force 10M Half Duplex + insmod dmfe mode=1 # Force 100M Half Duplex + insmod dmfe mode=4 # Force 10M Full Duplex + insmod dmfe mode=5 # Force 100M Full Duplex + +Next you should configure your network interface with a command similar to:: + + ifconfig eth0 172.22.3.18 + ^^^^^^^^^^^ + Your IP Address + +Then you may have to modify the default routing table with command:: + + route add default eth0 + + +Now your ethernet card should be up and running. + + +TODO: + +- Implement pci_driver::suspend() and pci_driver::resume() power management methods. +- Check on 64 bit boxes. +- Check and fix on big endian boxes. +- Test and make sure PCI latency is now correct for all cases. + + +Authors: + +Sten Wang <sten_wang@davicom.com.tw > : Original Author + +Contributors: + +- Marcelo Tosatti <marcelo@conectiva.com.br> +- Alan Cox <alan@lxorguk.ukuu.org.uk> +- Jeff Garzik <jgarzik@pobox.com> +- Vojtech Pavlik <vojtech@suse.cz> diff --git a/Documentation/networking/device_drivers/ethernet/dlink/dl2k.rst b/Documentation/networking/device_drivers/ethernet/dlink/dl2k.rst new file mode 100644 index 0000000000..ccdb5d0d74 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/dlink/dl2k.rst @@ -0,0 +1,314 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================================================= +D-Link DL2000-based Gigabit Ethernet Adapter Installation +========================================================= + +May 23, 2002 + +.. Contents + + - Compatibility List + - Quick Install + - Compiling the Driver + - Installing the Driver + - Option parameter + - Configuration Script Sample + - Troubleshooting + + +Compatibility List +================== + +Adapter Support: + +- D-Link DGE-550T Gigabit Ethernet Adapter. +- D-Link DGE-550SX Gigabit Ethernet Adapter. +- D-Link DL2000-based Gigabit Ethernet Adapter. + + +The driver support Linux kernel 2.4.7 later. We had tested it +on the environments below. + + . Red Hat v6.2 (update kernel to 2.4.7) + . Red Hat v7.0 (update kernel to 2.4.7) + . Red Hat v7.1 (kernel 2.4.7) + . Red Hat v7.2 (kernel 2.4.7-10) + + +Quick Install +============= +Install linux driver as following command:: + + 1. make all + 2. insmod dl2k.ko + 3. ifconfig eth0 up 10.xxx.xxx.xxx netmask 255.0.0.0 + ^^^^^^^^^^^^^^^\ ^^^^^^^^\ + IP NETMASK + +Now eth0 should active, you can test it by "ping" or get more information by +"ifconfig". If tested ok, continue the next step. + +4. ``cp dl2k.ko /lib/modules/`uname -r`/kernel/drivers/net`` +5. Add the following line to /etc/modprobe.d/dl2k.conf:: + + alias eth0 dl2k + +6. Run ``depmod`` to updated module indexes. +7. Run ``netconfig`` or ``netconf`` to create configuration script ifcfg-eth0 + located at /etc/sysconfig/network-scripts or create it manually. + + [see - Configuration Script Sample] +8. Driver will automatically load and configure at next boot time. + +Compiling the Driver +==================== +In Linux, NIC drivers are most commonly configured as loadable modules. +The approach of building a monolithic kernel has become obsolete. The driver +can be compiled as part of a monolithic kernel, but is strongly discouraged. +The remainder of this section assumes the driver is built as a loadable module. +In the Linux environment, it is a good idea to rebuild the driver from the +source instead of relying on a precompiled version. This approach provides +better reliability since a precompiled driver might depend on libraries or +kernel features that are not present in a given Linux installation. + +The 3 files necessary to build Linux device driver are dl2k.c, dl2k.h and +Makefile. To compile, the Linux installation must include the gcc compiler, +the kernel source, and the kernel headers. The Linux driver supports Linux +Kernels 2.4.7. Copy the files to a directory and enter the following command +to compile and link the driver: + +CD-ROM drive +------------ + +:: + + [root@XXX /] mkdir cdrom + [root@XXX /] mount -r -t iso9660 -o conv=auto /dev/cdrom /cdrom + [root@XXX /] cd root + [root@XXX /root] mkdir dl2k + [root@XXX /root] cd dl2k + [root@XXX dl2k] cp /cdrom/linux/dl2k.tgz /root/dl2k + [root@XXX dl2k] tar xfvz dl2k.tgz + [root@XXX dl2k] make all + +Floppy disc drive +----------------- + +:: + + [root@XXX /] cd root + [root@XXX /root] mkdir dl2k + [root@XXX /root] cd dl2k + [root@XXX dl2k] mcopy a:/linux/dl2k.tgz /root/dl2k + [root@XXX dl2k] tar xfvz dl2k.tgz + [root@XXX dl2k] make all + +Installing the Driver +===================== + +Manual Installation +------------------- + + Once the driver has been compiled, it must be loaded, enabled, and bound + to a protocol stack in order to establish network connectivity. To load a + module enter the command:: + + insmod dl2k.o + + or:: + + insmod dl2k.o <optional parameter> ; add parameter + +--------------------------------------------------------- + + example:: + + insmod dl2k.o media=100mbps_hd + + or:: + + insmod dl2k.o media=3 + + or:: + + insmod dl2k.o media=3,2 ; for 2 cards + +--------------------------------------------------------- + + Please reference the list of the command line parameters supported by + the Linux device driver below. + + The insmod command only loads the driver and gives it a name of the form + eth0, eth1, etc. To bring the NIC into an operational state, + it is necessary to issue the following command:: + + ifconfig eth0 up + + Finally, to bind the driver to the active protocol (e.g., TCP/IP with + Linux), enter the following command:: + + ifup eth0 + + Note that this is meaningful only if the system can find a configuration + script that contains the necessary network information. A sample will be + given in the next paragraph. + + The commands to unload a driver are as follows:: + + ifdown eth0 + ifconfig eth0 down + rmmod dl2k.o + + The following are the commands to list the currently loaded modules and + to see the current network configuration:: + + lsmod + ifconfig + + +Automated Installation +---------------------- + This section describes how to install the driver such that it is + automatically loaded and configured at boot time. The following description + is based on a Red Hat 6.0/7.0 distribution, but it can easily be ported to + other distributions as well. + +Red Hat v6.x/v7.x +----------------- + 1. Copy dl2k.o to the network modules directory, typically + /lib/modules/2.x.x-xx/net or /lib/modules/2.x.x/kernel/drivers/net. + 2. Locate the boot module configuration file, most commonly in the + /etc/modprobe.d/ directory. Add the following lines:: + + alias ethx dl2k + options dl2k <optional parameters> + + where ethx will be eth0 if the NIC is the only ethernet adapter, eth1 if + one other ethernet adapter is installed, etc. Refer to the table in the + previous section for the list of optional parameters. + 3. Locate the network configuration scripts, normally the + /etc/sysconfig/network-scripts directory, and create a configuration + script named ifcfg-ethx that contains network information. + 4. Note that for most Linux distributions, Red Hat included, a configuration + utility with a graphical user interface is provided to perform steps 2 + and 3 above. + + +Parameter Description +===================== +You can install this driver without any additional parameter. However, if you +are going to have extensive functions then it is necessary to set extra +parameter. Below is a list of the command line parameters supported by the +Linux device +driver. + + +=============================== ============================================== +mtu=packet_size Specifies the maximum packet size. default + is 1500. + +media=media_type Specifies the media type the NIC operates at. + autosense Autosensing active media. + + =========== ========================= + 10mbps_hd 10Mbps half duplex. + 10mbps_fd 10Mbps full duplex. + 100mbps_hd 100Mbps half duplex. + 100mbps_fd 100Mbps full duplex. + 1000mbps_fd 1000Mbps full duplex. + 1000mbps_hd 1000Mbps half duplex. + 0 Autosensing active media. + 1 10Mbps half duplex. + 2 10Mbps full duplex. + 3 100Mbps half duplex. + 4 100Mbps full duplex. + 5 1000Mbps half duplex. + 6 1000Mbps full duplex. + =========== ========================= + + By default, the NIC operates at autosense. + 1000mbps_fd and 1000mbps_hd types are only + available for fiber adapter. + +vlan=n Specifies the VLAN ID. If vlan=0, the + Virtual Local Area Network (VLAN) function is + disable. + +jumbo=[0|1] Specifies the jumbo frame support. If jumbo=1, + the NIC accept jumbo frames. By default, this + function is disabled. + Jumbo frame usually improve the performance + int gigabit. + This feature need jumbo frame compatible + remote. + +rx_coalesce=m Number of rx frame handled each interrupt. +rx_timeout=n Rx DMA wait time for an interrupt. + If set rx_coalesce > 0, hardware only assert + an interrupt for m frames. Hardware won't + assert rx interrupt until m frames received or + reach timeout of n * 640 nano seconds. + Set proper rx_coalesce and rx_timeout can + reduce congestion collapse and overload which + has been a bottleneck for high speed network. + + For example, rx_coalesce=10 rx_timeout=800. + that is, hardware assert only 1 interrupt + for 10 frames received or timeout of 512 us. + +tx_coalesce=n Number of tx frame handled each interrupt. + Set n > 1 can reduce the interrupts + congestion usually lower performance of + high speed network card. Default is 16. + +tx_flow=[1|0] Specifies the Tx flow control. If tx_flow=0, + the Tx flow control disable else driver + autodetect. +rx_flow=[1|0] Specifies the Rx flow control. If rx_flow=0, + the Rx flow control enable else driver + autodetect. +=============================== ============================================== + + +Configuration Script Sample +=========================== +Here is a sample of a simple configuration script:: + + DEVICE=eth0 + USERCTL=no + ONBOOT=yes + POOTPROTO=none + BROADCAST=207.200.5.255 + NETWORK=207.200.5.0 + NETMASK=255.255.255.0 + IPADDR=207.200.5.2 + + +Troubleshooting +=============== +Q1. Source files contain ^ M behind every line. + + Make sure all files are Unix file format (no LF). Try the following + shell command to convert files:: + + cat dl2k.c | col -b > dl2k.tmp + mv dl2k.tmp dl2k.c + + OR:: + + cat dl2k.c | tr -d "\r" > dl2k.tmp + mv dl2k.tmp dl2k.c + +Q2: Could not find header files (``*.h``)? + + To compile the driver, you need kernel header files. After + installing the kernel source, the header files are usually located in + /usr/src/linux/include, which is the default include directory configured + in Makefile. For some distributions, there is a copy of header files in + /usr/src/include/linux and /usr/src/include/asm, that you can change the + INCLUDEDIR in Makefile to /usr/include without installing kernel source. + + Note that RH 7.0 didn't provide correct header files in /usr/include, + including those files will make a wrong version driver. + diff --git a/Documentation/networking/device_drivers/ethernet/freescale/dpaa.rst b/Documentation/networking/device_drivers/ethernet/freescale/dpaa.rst new file mode 100644 index 0000000000..241c6c6f6e --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/freescale/dpaa.rst @@ -0,0 +1,269 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================== +The QorIQ DPAA Ethernet Driver +============================== + +Authors: +- Madalin Bucur <madalin.bucur@nxp.com> +- Camelia Groza <camelia.groza@nxp.com> + +.. Contents + + - DPAA Ethernet Overview + - DPAA Ethernet Supported SoCs + - Configuring DPAA Ethernet in your kernel + - DPAA Ethernet Frame Processing + - DPAA Ethernet Features + - DPAA IRQ Affinity and Receive Side Scaling + - Debugging + +DPAA Ethernet Overview +====================== + +DPAA stands for Data Path Acceleration Architecture and it is a +set of networking acceleration IPs that are available on several +generations of SoCs, both on PowerPC and ARM64. + +The Freescale DPAA architecture consists of a series of hardware blocks +that support Ethernet connectivity. The Ethernet driver depends upon the +following drivers in the Linux kernel: + + - Peripheral Access Memory Unit (PAMU) (* needed only for PPC platforms) + drivers/iommu/fsl_* + - Frame Manager (FMan) + drivers/net/ethernet/freescale/fman + - Queue Manager (QMan), Buffer Manager (BMan) + drivers/soc/fsl/qbman + +A simplified view of the dpaa_eth interfaces mapped to FMan MACs:: + + dpaa_eth /eth0\ ... /ethN\ + driver | | | | + ------------- ---- ----------- ---- ------------- + -Ports / Tx Rx \ ... / Tx Rx \ + FMan | | | | + -MACs | MAC0 | | MACN | + / dtsec0 \ ... / dtsecN \ (or tgec) + / \ / \(or memac) + --------- -------------- --- -------------- --------- + FMan, FMan Port, FMan SP, FMan MURAM drivers + --------------------------------------------------------- + FMan HW blocks: MURAM, MACs, Ports, SP + --------------------------------------------------------- + +The dpaa_eth relation to the QMan, BMan and FMan:: + + ________________________________ + dpaa_eth / eth0 \ + driver / \ + --------- -^- -^- -^- --- --------- + QMan driver / \ / \ / \ \ / | BMan | + |Rx | |Rx | |Tx | |Tx | | driver | + --------- |Dfl| |Err| |Cnf| |FQs| | | + QMan HW |FQ | |FQ | |FQs| | | | | + / \ / \ / \ \ / | | + --------- --- --- --- -v- --------- + | FMan QMI | | + | FMan HW FMan BMI | BMan HW | + ----------------------- -------- + +where the acronyms used above (and in the code) are: + +=============== =========================================================== +DPAA Data Path Acceleration Architecture +FMan DPAA Frame Manager +QMan DPAA Queue Manager +BMan DPAA Buffers Manager +QMI QMan interface in FMan +BMI BMan interface in FMan +FMan SP FMan Storage Profiles +MURAM Multi-user RAM in FMan +FQ QMan Frame Queue +Rx Dfl FQ default reception FQ +Rx Err FQ Rx error frames FQ +Tx Cnf FQ Tx confirmation FQs +Tx FQs transmission frame queues +dtsec datapath three speed Ethernet controller (10/100/1000 Mbps) +tgec ten gigabit Ethernet controller (10 Gbps) +memac multirate Ethernet MAC (10/100/1000/10000) +=============== =========================================================== + +DPAA Ethernet Supported SoCs +============================ + +The DPAA drivers enable the Ethernet controllers present on the following SoCs: + +PPC +- P1023 +- P2041 +- P3041 +- P4080 +- P5020 +- P5040 +- T1023 +- T1024 +- T1040 +- T1042 +- T2080 +- T4240 +- B4860 + +ARM +- LS1043A +- LS1046A + +Configuring DPAA Ethernet in your kernel +======================================== + +To enable the DPAA Ethernet driver, the following Kconfig options are required:: + + # common for arch/arm64 and arch/powerpc platforms + CONFIG_FSL_DPAA=y + CONFIG_FSL_FMAN=y + CONFIG_FSL_DPAA_ETH=y + CONFIG_FSL_XGMAC_MDIO=y + + # for arch/powerpc only + CONFIG_FSL_PAMU=y + + # common options needed for the PHYs used on the RDBs + CONFIG_VITESSE_PHY=y + CONFIG_REALTEK_PHY=y + CONFIG_AQUANTIA_PHY=y + +DPAA Ethernet Frame Processing +============================== + +On Rx, buffers for the incoming frames are retrieved from the buffers found +in the dedicated interface buffer pool. The driver initializes and seeds these +with one page buffers. + +On Tx, all transmitted frames are returned to the driver through Tx +confirmation frame queues. The driver is then responsible for freeing the +buffers. In order to do this properly, a backpointer is added to the buffer +before transmission that points to the skb. When the buffer returns to the +driver on a confirmation FQ, the skb can be correctly consumed. + +DPAA Ethernet Features +====================== + +Currently the DPAA Ethernet driver enables the basic features required for +a Linux Ethernet driver. The support for advanced features will be added +gradually. + +The driver has Rx and Tx checksum offloading for UDP and TCP. Currently the Rx +checksum offload feature is enabled by default and cannot be controlled through +ethtool. Also, rx-flow-hash and rx-hashing was added. The addition of RSS +provides a big performance boost for the forwarding scenarios, allowing +different traffic flows received by one interface to be processed by different +CPUs in parallel. + +The driver has support for multiple prioritized Tx traffic classes. Priorities +range from 0 (lowest) to 3 (highest). These are mapped to HW workqueues with +strict priority levels. Each traffic class contains NR_CPU TX queues. By +default, only one traffic class is enabled and the lowest priority Tx queues +are used. Higher priority traffic classes can be enabled with the mqprio +qdisc. For example, all four traffic classes are enabled on an interface with +the following command. Furthermore, skb priority levels are mapped to traffic +classes as follows: + + * priorities 0 to 3 - traffic class 0 (low priority) + * priorities 4 to 7 - traffic class 1 (medium-low priority) + * priorities 8 to 11 - traffic class 2 (medium-high priority) + * priorities 12 to 15 - traffic class 3 (high priority) + +:: + + tc qdisc add dev <int> root handle 1: \ + mqprio num_tc 4 map 0 0 0 0 1 1 1 1 2 2 2 2 3 3 3 3 hw 1 + +DPAA IRQ Affinity and Receive Side Scaling +========================================== + +Traffic coming on the DPAA Rx queues or on the DPAA Tx confirmation +queues is seen by the CPU as ingress traffic on a certain portal. +The DPAA QMan portal interrupts are affined each to a certain CPU. +The same portal interrupt services all the QMan portal consumers. + +By default the DPAA Ethernet driver enables RSS, making use of the +DPAA FMan Parser and Keygen blocks to distribute traffic on 128 +hardware frame queues using a hash on IP v4/v6 source and destination +and L4 source and destination ports, in present in the received frame. +When RSS is disabled, all traffic received by a certain interface is +received on the default Rx frame queue. The default DPAA Rx frame +queues are configured to put the received traffic into a pool channel +that allows any available CPU portal to dequeue the ingress traffic. +The default frame queues have the HOLDACTIVE option set, ensuring that +traffic bursts from a certain queue are serviced by the same CPU. +This ensures a very low rate of frame reordering. A drawback of this +is that only one CPU at a time can service the traffic received by a +certain interface when RSS is not enabled. + +To implement RSS, the DPAA Ethernet driver allocates an extra set of +128 Rx frame queues that are configured to dedicated channels, in a +round-robin manner. The mapping of the frame queues to CPUs is now +hardcoded, there is no indirection table to move traffic for a certain +FQ (hash result) to another CPU. The ingress traffic arriving on one +of these frame queues will arrive at the same portal and will always +be processed by the same CPU. This ensures intra-flow order preservation +and workload distribution for multiple traffic flows. + +RSS can be turned off for a certain interface using ethtool, i.e.:: + + # ethtool -N fm1-mac9 rx-flow-hash tcp4 "" + +To turn it back on, one needs to set rx-flow-hash for tcp4/6 or udp4/6:: + + # ethtool -N fm1-mac9 rx-flow-hash udp4 sfdn + +There is no independent control for individual protocols, any command +run for one of tcp4|udp4|ah4|esp4|sctp4|tcp6|udp6|ah6|esp6|sctp6 is +going to control the rx-flow-hashing for all protocols on that interface. + +Besides using the FMan Keygen computed hash for spreading traffic on the +128 Rx FQs, the DPAA Ethernet driver also sets the skb hash value when +the NETIF_F_RXHASH feature is on (active by default). This can be turned +on or off through ethtool, i.e.:: + + # ethtool -K fm1-mac9 rx-hashing off + # ethtool -k fm1-mac9 | grep hash + receive-hashing: off + # ethtool -K fm1-mac9 rx-hashing on + Actual changes: + receive-hashing: on + # ethtool -k fm1-mac9 | grep hash + receive-hashing: on + +Please note that Rx hashing depends upon the rx-flow-hashing being on +for that interface - turning off rx-flow-hashing will also disable the +rx-hashing (without ethtool reporting it as off as that depends on the +NETIF_F_RXHASH feature flag). + +Debugging +========= + +The following statistics are exported for each interface through ethtool: + + - interrupt count per CPU + - Rx packets count per CPU + - Tx packets count per CPU + - Tx confirmed packets count per CPU + - Tx S/G frames count per CPU + - Tx error count per CPU + - Rx error count per CPU + - Rx error count per type + - congestion related statistics: + + - congestion status + - time spent in congestion + - number of time the device entered congestion + - dropped packets count per cause + +The driver also exports the following information in sysfs: + + - the FQ IDs for each FQ type + /sys/devices/platform/soc/<addr>.fman/<addr>.ethernet/dpaa-ethernet.<id>/net/fm<nr>-mac<nr>/fqids + + - the ID of the buffer pool in use + /sys/devices/platform/soc/<addr>.fman/<addr>.ethernet/dpaa-ethernet.<id>/net/fm<nr>-mac<nr>/bpids diff --git a/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/dpio-driver.rst b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/dpio-driver.rst new file mode 100644 index 0000000000..e4ebfe62a1 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/dpio-driver.rst @@ -0,0 +1,161 @@ +.. include:: <isonum.txt> + +=================================== +DPAA2 DPIO (Data Path I/O) Overview +=================================== + +:Copyright: |copy| 2016-2018 NXP + +This document provides an overview of the Freescale DPAA2 DPIO +drivers + +Introduction +============ + +A DPAA2 DPIO (Data Path I/O) is a hardware object that provides +interfaces to enqueue and dequeue frames to/from network interfaces +and other accelerators. A DPIO also provides hardware buffer +pool management for network interfaces. + +This document provides an overview the Linux DPIO driver, its +subcomponents, and its APIs. + +See +Documentation/networking/device_drivers/ethernet/freescale/dpaa2/overview.rst +for a general overview of DPAA2 and the general DPAA2 driver architecture +in Linux. + +Driver Overview +--------------- + +The DPIO driver is bound to DPIO objects discovered on the fsl-mc bus and +provides services that: + + A. allow other drivers, such as the Ethernet driver, to enqueue and dequeue + frames for their respective objects + B. allow drivers to register callbacks for data availability notifications + when data becomes available on a queue or channel + C. allow drivers to manage hardware buffer pools + +The Linux DPIO driver consists of 3 primary components-- + DPIO object driver-- fsl-mc driver that manages the DPIO object + + DPIO service-- provides APIs to other Linux drivers for services + + QBman portal interface-- sends portal commands, gets responses:: + + fsl-mc other + bus drivers + | | + +---+----+ +------+-----+ + |DPIO obj| |DPIO service| + | driver |---| (DPIO) | + +--------+ +------+-----+ + | + +------+-----+ + | QBman | + | portal i/f | + +------------+ + | + hardware + + +The diagram below shows how the DPIO driver components fit with the other +DPAA2 Linux driver components:: + + +------------+ + | OS Network | + | Stack | + +------------+ +------------+ + | Allocator |. . . . . . . | Ethernet | + |(DPMCP,DPBP)| | (DPNI) | + +-.----------+ +---+---+----+ + . . ^ | + . . <data avail, | |<enqueue, + . . tx confirm> | | dequeue> + +-------------+ . | | + | DPRC driver | . +--------+ +------------+ + | (DPRC) | . . |DPIO obj| |DPIO service| + +----------+--+ | driver |-| (DPIO) | + | +--------+ +------+-----+ + |<dev add/remove> +------|-----+ + | | QBman | + +----+--------------+ | portal i/f | + | MC-bus driver | +------------+ + | | | + | /soc/fsl-mc | | + +-------------------+ | + | + =========================================|=========|======================== + +-+--DPIO---|-----------+ + | | | + | QBman Portal | + +-----------------------+ + + ============================================================================ + + +DPIO Object Driver (dpio-driver.c) +---------------------------------- + + The dpio-driver component registers with the fsl-mc bus to handle objects of + type "dpio". The implementation of probe() handles basic initialization + of the DPIO including mapping of the DPIO regions (the QBman SW portal) + and initializing interrupts and registering irq handlers. The dpio-driver + registers the probed DPIO with dpio-service. + +DPIO service (dpio-service.c, dpaa2-io.h) +------------------------------------------ + + The dpio service component provides queuing, notification, and buffers + management services to DPAA2 drivers, such as the Ethernet driver. A system + will typically allocate 1 DPIO object per CPU to allow queuing operations + to happen simultaneously across all CPUs. + + Notification handling + dpaa2_io_service_register() + + dpaa2_io_service_deregister() + + dpaa2_io_service_rearm() + + Queuing + dpaa2_io_service_pull_fq() + + dpaa2_io_service_pull_channel() + + dpaa2_io_service_enqueue_fq() + + dpaa2_io_service_enqueue_qd() + + dpaa2_io_store_create() + + dpaa2_io_store_destroy() + + dpaa2_io_store_next() + + Buffer pool management + dpaa2_io_service_release() + + dpaa2_io_service_acquire() + +QBman portal interface (qbman-portal.c) +--------------------------------------- + + The qbman-portal component provides APIs to do the low level hardware + bit twiddling for operations such as: + + - initializing Qman software portals + - building and sending portal commands + - portal interrupt configuration and processing + + The qbman-portal APIs are not public to other drivers, and are + only used by dpio-service. + +Other (dpaa2-fd.h, dpaa2-global.h) +---------------------------------- + + Frame descriptor and scatter-gather definitions and the APIs used to + manipulate them are defined in dpaa2-fd.h. + + Dequeue result struct and parsing APIs are defined in dpaa2-global.h. diff --git a/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/ethernet-driver.rst b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/ethernet-driver.rst new file mode 100644 index 0000000000..682f3986c1 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/ethernet-driver.rst @@ -0,0 +1,186 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> + +=============================== +DPAA2 Ethernet driver +=============================== + +:Copyright: |copy| 2017-2018 NXP + +This file provides documentation for the Freescale DPAA2 Ethernet driver. + +Supported Platforms +=================== +This driver provides networking support for Freescale DPAA2 SoCs, e.g. +LS2080A, LS2088A, LS1088A. + + +Architecture Overview +===================== +Unlike regular NICs, in the DPAA2 architecture there is no single hardware block +representing network interfaces; instead, several separate hardware resources +concur to provide the networking functionality: + +- network interfaces +- queues, channels +- buffer pools +- MAC/PHY + +All hardware resources are allocated and configured through the Management +Complex (MC) portals. MC abstracts most of these resources as DPAA2 objects +and exposes ABIs through which they can be configured and controlled. A few +hardware resources, like queues, do not have a corresponding MC object and +are treated as internal resources of other objects. + +For a more detailed description of the DPAA2 architecture and its object +abstractions see +*Documentation/networking/device_drivers/ethernet/freescale/dpaa2/overview.rst*. + +Each Linux net device is built on top of a Datapath Network Interface (DPNI) +object and uses Buffer Pools (DPBPs), I/O Portals (DPIOs) and Concentrators +(DPCONs). + +Configuration interface:: + + ----------------------- + | DPAA2 Ethernet Driver | + ----------------------- + . . . + . . . + . . . . . . . . . . . . + . . . + . . . + ---------- ---------- ----------- + | DPBP API | | DPNI API | | DPCON API | + ---------- ---------- ----------- + . . . software + ======= . ========== . ============ . =================== + . . . hardware + ------------------------------------------ + | MC hardware portals | + ------------------------------------------ + . . . + . . . + ------ ------ ------- + | DPBP | | DPNI | | DPCON | + ------ ------ ------- + +The DPNIs are network interfaces without a direct one-on-one mapping to PHYs. +DPBPs represent hardware buffer pools. Packet I/O is performed in the context +of DPCON objects, using DPIO portals for managing and communicating with the +hardware resources. + +Datapath (I/O) interface:: + + ----------------------------------------------- + | DPAA2 Ethernet Driver | + ----------------------------------------------- + | ^ ^ | | + | | | | | + enqueue| dequeue| data | dequeue| seed | + (Tx) | (Rx, TxC)| avail.| request| buffers| + | | notify| | | + | | | | | + V | | V V + ----------------------------------------------- + | DPIO Driver | + ----------------------------------------------- + | | | | | software + | | | | | ================ + | | | | | hardware + ----------------------------------------------- + | I/O hardware portals | + ----------------------------------------------- + | ^ ^ | | + | | | | | + | | | V | + V | ================ V + ---------------------- | ------------- + queues ---------------------- | | Buffer pool | + ---------------------- | ------------- + ======================= + Channel + +Datapath I/O (DPIO) portals provide enqueue and dequeue services, data +availability notifications and buffer pool management. DPIOs are shared between +all DPAA2 objects (and implicitly all DPAA2 kernel drivers) that work with data +frames, but must be affine to the CPUs for the purpose of traffic distribution. + +Frames are transmitted and received through hardware frame queues, which can be +grouped in channels for the purpose of hardware scheduling. The Ethernet driver +enqueues TX frames on egress queues and after transmission is complete a TX +confirmation frame is sent back to the CPU. + +When frames are available on ingress queues, a data availability notification +is sent to the CPU; notifications are raised per channel, so even if multiple +queues in the same channel have available frames, only one notification is sent. +After a channel fires a notification, is must be explicitly rearmed. + +Each network interface can have multiple Rx, Tx and confirmation queues affined +to CPUs, and one channel (DPCON) for each CPU that services at least one queue. +DPCONs are used to distribute ingress traffic to different CPUs via the cores' +affine DPIOs. + +The role of hardware buffer pools is storage of ingress frame data. Each network +interface has a privately owned buffer pool which it seeds with kernel allocated +buffers. + + +DPNIs are decoupled from PHYs; a DPNI can be connected to a PHY through a DPMAC +object or to another DPNI through an internal link, but the connection is +managed by MC and completely transparent to the Ethernet driver. + +:: + + --------- --------- --------- + | eth if1 | | eth if2 | | eth ifn | + --------- --------- --------- + . . . + . . . + . . . + --------------------------- + | DPAA2 Ethernet Driver | + --------------------------- + . . . + . . . + . . . + ------ ------ ------ ------- + | DPNI | | DPNI | | DPNI | | DPMAC |----+ + ------ ------ ------ ------- | + | | | | | + | | | | ----- + =========== ================== | PHY | + ----- + +Creating a Network Interface +============================ +A net device is created for each DPNI object probed on the MC bus. Each DPNI has +a number of properties which determine the network interface configuration +options and associated hardware resources. + +DPNI objects (and the other DPAA2 objects needed for a network interface) can be +added to a container on the MC bus in one of two ways: statically, through a +Datapath Layout Binary file (DPL) that is parsed by MC at boot time; or created +dynamically at runtime, via the DPAA2 objects APIs. + + +Features & Offloads +=================== +Hardware checksum offloading is supported for TCP and UDP over IPv4/6 frames. +The checksum offloads can be independently configured on RX and TX through +ethtool. + +Hardware offload of unicast and multicast MAC filtering is supported on the +ingress path and permanently enabled. + +Scatter-gather frames are supported on both RX and TX paths. On TX, SG support +is configurable via ethtool; on RX it is always enabled. + +The DPAA2 hardware can process jumbo Ethernet frames of up to 10K bytes. + +The Ethernet driver defines a static flow hashing scheme that distributes +traffic based on a 5-tuple key: src IP, dst IP, IP proto, L4 src port, +L4 dst port. No user configuration is supported for now. + +Hardware specific statistics for the network interface as well as some +non-standard driver stats can be consulted through ethtool -S option. diff --git a/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/index.rst b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/index.rst new file mode 100644 index 0000000000..62f4a4aff6 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/index.rst @@ -0,0 +1,12 @@ +=================== +DPAA2 Documentation +=================== + +.. toctree:: + :maxdepth: 1 + + overview + dpio-driver + ethernet-driver + mac-phy-support + switch-driver diff --git a/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/mac-phy-support.rst b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/mac-phy-support.rst new file mode 100644 index 0000000000..e2a36d0d88 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/mac-phy-support.rst @@ -0,0 +1,194 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> + +======================= +DPAA2 MAC / PHY support +======================= + +:Copyright: |copy| 2019 NXP + +Overview +-------- + +The DPAA2 MAC / PHY support consists of a set of APIs that help DPAA2 network +drivers (dpaa2-eth, dpaa2-ethsw) interact with the PHY library. + +DPAA2 Software Architecture +--------------------------- + +Among other DPAA2 objects, the fsl-mc bus exports DPNI objects (abstracting a +network interface) and DPMAC objects (abstracting a MAC). The dpaa2-eth driver +probes on the DPNI object and connects to and configures a DPMAC object with +the help of phylink. + +Data connections may be established between a DPNI and a DPMAC, or between two +DPNIs. Depending on the connection type, the netif_carrier_[on/off] is handled +directly by the dpaa2-eth driver or by phylink. + +.. code-block:: none + + Sources of abstracted link state information presented by the MC firmware + + +--------------------------------------+ + +------------+ +---------+ | xgmac_mdio | + | net_device | | phylink |--| +-----+ +-----+ +-----+ +-----+ | + +------------+ +---------+ | | PHY | | PHY | | PHY | | PHY | | + | | | +-----+ +-----+ +-----+ +-----+ | + +------------------------------------+ | External MDIO bus | + | dpaa2-eth | +--------------------------------------+ + +------------------------------------+ + | | Linux + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + | | MC firmware + | /| V + +----------+ / | +----------+ + | | / | | | + | | | | | | + | DPNI |<------| |<------| DPMAC | + | | | | | | + | | \ |<---+ | | + +----------+ \ | | +----------+ + \| | + | + +--------------------------------------+ + | MC firmware polling MAC PCS for link | + | +-----+ +-----+ +-----+ +-----+ | + | | PCS | | PCS | | PCS | | PCS | | + | +-----+ +-----+ +-----+ +-----+ | + | Internal MDIO bus | + +--------------------------------------+ + + +Depending on an MC firmware configuration setting, each MAC may be in one of two modes: + +- DPMAC_LINK_TYPE_FIXED: the link state management is handled exclusively by + the MC firmware by polling the MAC PCS. Without the need to register a + phylink instance, the dpaa2-eth driver will not bind to the connected dpmac + object at all. + +- DPMAC_LINK_TYPE_PHY: The MC firmware is left waiting for link state update + events, but those are in fact passed strictly between the dpaa2-mac (based on + phylink) and its attached net_device driver (dpaa2-eth, dpaa2-ethsw), + effectively bypassing the firmware. + +Implementation +-------------- + +At probe time or when a DPNI's endpoint is dynamically changed, the dpaa2-eth +is responsible to find out if the peer object is a DPMAC and if this is the +case, to integrate it with PHYLINK using the dpaa2_mac_connect() API, which +will do the following: + + - look up the device tree for PHYLINK-compatible of binding (phy-handle) + - will create a PHYLINK instance associated with the received net_device + - connect to the PHY using phylink_of_phy_connect() + +The following phylink_mac_ops callback are implemented: + + - .validate() will populate the supported linkmodes with the MAC capabilities + only when the phy_interface_t is RGMII_* (at the moment, this is the only + link type supported by the driver). + + - .mac_config() will configure the MAC in the new configuration using the + dpmac_set_link_state() MC firmware API. + + - .mac_link_up() / .mac_link_down() will update the MAC link using the same + API described above. + +At driver unbind() or when the DPNI object is disconnected from the DPMAC, the +dpaa2-eth driver calls dpaa2_mac_disconnect() which will, in turn, disconnect +from the PHY and destroy the PHYLINK instance. + +In case of a DPNI-DPMAC connection, an 'ip link set dev eth0 up' would start +the following sequence of operations: + +(1) phylink_start() called from .dev_open(). +(2) The .mac_config() and .mac_link_up() callbacks are called by PHYLINK. +(3) In order to configure the HW MAC, the MC Firmware API + dpmac_set_link_state() is called. +(4) The firmware will eventually setup the HW MAC in the new configuration. +(5) A netif_carrier_on() call is made directly from PHYLINK on the associated + net_device. +(6) The dpaa2-eth driver handles the LINK_STATE_CHANGE irq in order to + enable/disable Rx taildrop based on the pause frame settings. + +.. code-block:: none + + +---------+ +---------+ + | PHYLINK |-------------->| eth0 | + +---------+ (5) +---------+ + (1) ^ | + | | + | v (2) + +-----------------------------------+ + | dpaa2-eth | + +-----------------------------------+ + | ^ (6) + | | + v (3) | + +---------+---------------+---------+ + | DPMAC | | DPNI | + +---------+ +---------+ + | MC Firmware | + +-----------------------------------+ + | + | + v (4) + +-----------------------------------+ + | HW MAC | + +-----------------------------------+ + +In case of a DPNI-DPNI connection, a usual sequence of operations looks like +the following: + +(1) ip link set dev eth0 up +(2) The dpni_enable() MC API called on the associated fsl_mc_device. +(3) ip link set dev eth1 up +(4) The dpni_enable() MC API called on the associated fsl_mc_device. +(5) The LINK_STATE_CHANGED irq is received by both instances of the dpaa2-eth + driver because now the operational link state is up. +(6) The netif_carrier_on() is called on the exported net_device from + link_state_update(). + +.. code-block:: none + + +---------+ +---------+ + | eth0 | | eth1 | + +---------+ +---------+ + | ^ ^ | + | | | | + (1) v | (6) (6) | v (3) + +---------+ +---------+ + |dpaa2-eth| |dpaa2-eth| + +---------+ +---------+ + | ^ ^ | + | | | | + (2) v | (5) (5) | v (4) + +---------+---------------+---------+ + | DPNI | | DPNI | + +---------+ +---------+ + | MC Firmware | + +-----------------------------------+ + + +Exported API +------------ + +Any DPAA2 driver that drivers endpoints of DPMAC objects should service its +_EVENT_ENDPOINT_CHANGED irq and connect/disconnect from the associated DPMAC +when necessary using the below listed API:: + + - int dpaa2_mac_connect(struct dpaa2_mac *mac); + - void dpaa2_mac_disconnect(struct dpaa2_mac *mac); + +A phylink integration is necessary only when the partner DPMAC is not of +``TYPE_FIXED``. This means it is either of ``TYPE_PHY``, or of +``TYPE_BACKPLANE`` (the difference being the two that in the ``TYPE_BACKPLANE`` +mode, the MC firmware does not access the PCS registers). One can check for +this condition using the following helper:: + + - static inline bool dpaa2_mac_is_type_phy(struct dpaa2_mac *mac); + +Before connection to a MAC, the caller must allocate and populate the +dpaa2_mac structure with the associated net_device, a pointer to the MC portal +to be used and the actual fsl_mc_device structure of the DPMAC. diff --git a/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/overview.rst b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/overview.rst new file mode 100644 index 0000000000..1996477292 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/overview.rst @@ -0,0 +1,406 @@ +.. include:: <isonum.txt> + +========================================================= +DPAA2 (Data Path Acceleration Architecture Gen2) Overview +========================================================= + +:Copyright: |copy| 2015 Freescale Semiconductor Inc. +:Copyright: |copy| 2018 NXP + +This document provides an overview of the Freescale DPAA2 architecture +and how it is integrated into the Linux kernel. + +Introduction +============ + +DPAA2 is a hardware architecture designed for high-speeed network +packet processing. DPAA2 consists of sophisticated mechanisms for +processing Ethernet packets, queue management, buffer management, +autonomous L2 switching, virtual Ethernet bridging, and accelerator +(e.g. crypto) sharing. + +A DPAA2 hardware component called the Management Complex (or MC) manages the +DPAA2 hardware resources. The MC provides an object-based abstraction for +software drivers to use the DPAA2 hardware. +The MC uses DPAA2 hardware resources such as queues, buffer pools, and +network ports to create functional objects/devices such as network +interfaces, an L2 switch, or accelerator instances. +The MC provides memory-mapped I/O command interfaces (MC portals) +which DPAA2 software drivers use to operate on DPAA2 objects. + +The diagram below shows an overview of the DPAA2 resource management +architecture:: + + +--------------------------------------+ + | OS | + | DPAA2 drivers | + | | | + +-----------------------------|--------+ + | + | (create,discover,connect + | config,use,destroy) + | + DPAA2 | + +------------------------| mc portal |-+ + | | | + | +- - - - - - - - - - - - -V- - -+ | + | | | | + | | Management Complex (MC) | | + | | | | + | +- - - - - - - - - - - - - - - -+ | + | | + | Hardware Hardware | + | Resources Objects | + | --------- ------- | + | -queues -DPRC | + | -buffer pools -DPMCP | + | -Eth MACs/ports -DPIO | + | -network interface -DPNI | + | profiles -DPMAC | + | -queue portals -DPBP | + | -MC portals ... | + | ... | + | | + +--------------------------------------+ + + +The MC mediates operations such as create, discover, +connect, configuration, and destroy. Fast-path operations +on data, such as packet transmit/receive, are not mediated by +the MC and are done directly using memory mapped regions in +DPIO objects. + +Overview of DPAA2 Objects +========================= + +The section provides a brief overview of some key DPAA2 objects. +A simple scenario is described illustrating the objects involved +in creating a network interfaces. + +DPRC (Datapath Resource Container) +---------------------------------- + +A DPRC is a container object that holds all the other +types of DPAA2 objects. In the example diagram below there +are 8 objects of 5 types (DPMCP, DPIO, DPBP, DPNI, and DPMAC) +in the container. + +:: + + +---------------------------------------------------------+ + | DPRC | + | | + | +-------+ +-------+ +-------+ +-------+ +-------+ | + | | DPMCP | | DPIO | | DPBP | | DPNI | | DPMAC | | + | +-------+ +-------+ +-------+ +---+---+ +---+---+ | + | | DPMCP | | DPIO | | + | +-------+ +-------+ | + | | DPMCP | | + | +-------+ | + | | + +---------------------------------------------------------+ + +From the point of view of an OS, a DPRC behaves similar to a plug and +play bus, like PCI. DPRC commands can be used to enumerate the contents +of the DPRC, discover the hardware objects present (including mappable +regions and interrupts). + +:: + + DPRC.1 (bus) + | + +--+--------+-------+-------+-------+ + | | | | | + DPMCP.1 DPIO.1 DPBP.1 DPNI.1 DPMAC.1 + DPMCP.2 DPIO.2 + DPMCP.3 + +Hardware objects can be created and destroyed dynamically, providing +the ability to hot plug/unplug objects in and out of the DPRC. + +A DPRC has a mappable MMIO region (an MC portal) that can be used +to send MC commands. It has an interrupt for status events (like +hotplug). +All objects in a container share the same hardware "isolation context". +This means that with respect to an IOMMU the isolation granularity +is at the DPRC (container) level, not at the individual object +level. + +DPRCs can be defined statically and populated with objects +via a config file passed to the MC when firmware starts it. + +DPAA2 Objects for an Ethernet Network Interface +----------------------------------------------- + +A typical Ethernet NIC is monolithic-- the NIC device contains TX/RX +queuing mechanisms, configuration mechanisms, buffer management, +physical ports, and interrupts. DPAA2 uses a more granular approach +utilizing multiple hardware objects. Each object provides specialized +functions. Groups of these objects are used by software to provide +Ethernet network interface functionality. This approach provides +efficient use of finite hardware resources, flexibility, and +performance advantages. + +The diagram below shows the objects needed for a simple +network interface configuration on a system with 2 CPUs. + +:: + + +---+---+ +---+---+ + CPU0 CPU1 + +---+---+ +---+---+ + | | + +---+---+ +---+---+ + DPIO DPIO + +---+---+ +---+---+ + \ / + \ / + \ / + +---+---+ + DPNI --- DPBP,DPMCP + +---+---+ + | + | + +---+---+ + DPMAC + +---+---+ + | + port/PHY + +Below the objects are described. For each object a brief description +is provided along with a summary of the kinds of operations the object +supports and a summary of key resources of the object (MMIO regions +and IRQs). + +DPMAC (Datapath Ethernet MAC) +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Represents an Ethernet MAC, a hardware device that connects to an Ethernet +PHY and allows physical transmission and reception of Ethernet frames. + +- MMIO regions: none +- IRQs: DPNI link change +- commands: set link up/down, link config, get stats, + IRQ config, enable, reset + +DPNI (Datapath Network Interface) +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Contains TX/RX queues, network interface configuration, and RX buffer pool +configuration mechanisms. The TX/RX queues are in memory and are identified +by queue number. + +- MMIO regions: none +- IRQs: link state +- commands: port config, offload config, queue config, + parse/classify config, IRQ config, enable, reset + +DPIO (Datapath I/O) +~~~~~~~~~~~~~~~~~~~ +Provides interfaces to enqueue and dequeue +packets and do hardware buffer pool management operations. The DPAA2 +architecture separates the mechanism to access queues (the DPIO object) +from the queues themselves. The DPIO provides an MMIO interface to +enqueue/dequeue packets. To enqueue something a descriptor is written +to the DPIO MMIO region, which includes the target queue number. +There will typically be one DPIO assigned to each CPU. This allows all +CPUs to simultaneously perform enqueue/dequeued operations. DPIOs are +expected to be shared by different DPAA2 drivers. + +- MMIO regions: queue operations, buffer management +- IRQs: data availability, congestion notification, buffer + pool depletion +- commands: IRQ config, enable, reset + +DPBP (Datapath Buffer Pool) +~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Represents a hardware buffer pool. + +- MMIO regions: none +- IRQs: none +- commands: enable, reset + +DPMCP (Datapath MC Portal) +~~~~~~~~~~~~~~~~~~~~~~~~~~ +Provides an MC command portal. +Used by drivers to send commands to the MC to manage +objects. + +- MMIO regions: MC command portal +- IRQs: command completion +- commands: IRQ config, enable, reset + +Object Connections +================== +Some objects have explicit relationships that must +be configured: + +- DPNI <--> DPMAC +- DPNI <--> DPNI +- DPNI <--> L2-switch-port + + A DPNI must be connected to something such as a DPMAC, + another DPNI, or L2 switch port. The DPNI connection + is made via a DPRC command. + +:: + + +-------+ +-------+ + | DPNI | | DPMAC | + +---+---+ +---+---+ + | | + +==========+ + +- DPNI <--> DPBP + + A network interface requires a 'buffer pool' (DPBP + object) which provides a list of pointers to memory + where received Ethernet data is to be copied. The + Ethernet driver configures the DPBPs associated with + the network interface. + +Interrupts +========== +All interrupts generated by DPAA2 objects are message +interrupts. At the hardware level message interrupts +generated by devices will normally have 3 components-- +1) a non-spoofable 'device-id' expressed on the hardware +bus, 2) an address, 3) a data value. + +In the case of DPAA2 devices/objects, all objects in the +same container/DPRC share the same 'device-id'. +For ARM-based SoC this is the same as the stream ID. + + +DPAA2 Linux Drivers Overview +============================ + +This section provides an overview of the Linux kernel drivers for +DPAA2-- 1) the bus driver and associated "DPAA2 infrastructure" +drivers and 2) functional object drivers (such as Ethernet). + +As described previously, a DPRC is a container that holds the other +types of DPAA2 objects. It is functionally similar to a plug-and-play +bus controller. +Each object in the DPRC is a Linux "device" and is bound to a driver. +The diagram below shows the Linux drivers involved in a networking +scenario and the objects bound to each driver. A brief description +of each driver follows. + +:: + + +------------+ + | OS Network | + | Stack | + +------------+ +------------+ + | Allocator |. . . . . . . | Ethernet | + |(DPMCP,DPBP)| | (DPNI) | + +-.----------+ +---+---+----+ + . . ^ | + . . <data avail, | | <enqueue, + . . tx confirm> | | dequeue> + +-------------+ . | | + | DPRC driver | . +---+---V----+ +---------+ + | (DPRC) | . . . . . .| DPIO driver| | MAC | + +----------+--+ | (DPIO) | | (DPMAC) | + | +------+-----+ +-----+---+ + |<dev add/remove> | | + | | | + +--------+----------+ | +--+---+ + | MC-bus driver | | | PHY | + | | | |driver| + | /bus/fsl-mc | | +--+---+ + +-------------------+ | | + | | + ========================= HARDWARE =========|=================|====== + DPIO | + | | + DPNI---DPBP | + | | + DPMAC | + | | + PHY ---------------+ + ============================================|======================== + +A brief description of each driver is provided below. + +MC-bus driver +------------- +The MC-bus driver is a platform driver and is probed from a +node in the device tree (compatible "fsl,qoriq-mc") passed in by boot +firmware. It is responsible for bootstrapping the DPAA2 kernel +infrastructure. +Key functions include: + +- registering a new bus type named "fsl-mc" with the kernel, + and implementing bus call-backs (e.g. match/uevent/dev_groups) +- implementing APIs for DPAA2 driver registration and for device + add/remove +- creates an MSI IRQ domain +- doing a 'device add' to expose the 'root' DPRC, in turn triggering + a bind of the root DPRC to the DPRC driver + +The binding for the MC-bus device-tree node can be consulted at +*Documentation/devicetree/bindings/misc/fsl,qoriq-mc.txt*. +The sysfs bind/unbind interfaces for the MC-bus can be consulted at +*Documentation/ABI/testing/sysfs-bus-fsl-mc*. + +DPRC driver +----------- +The DPRC driver is bound to DPRC objects and does runtime management +of a bus instance. It performs the initial bus scan of the DPRC +and handles interrupts for container events such as hot plug by +re-scanning the DPRC. + +Allocator +--------- +Certain objects such as DPMCP and DPBP are generic and fungible, +and are intended to be used by other drivers. For example, +the DPAA2 Ethernet driver needs: + +- DPMCPs to send MC commands, to configure network interfaces +- DPBPs for network buffer pools + +The allocator driver registers for these allocatable object types +and those objects are bound to the allocator when the bus is probed. +The allocator maintains a pool of objects that are available for +allocation by other DPAA2 drivers. + +DPIO driver +----------- +The DPIO driver is bound to DPIO objects and provides services that allow +other drivers such as the Ethernet driver to enqueue and dequeue data for +their respective objects. +Key services include: + +- data availability notifications +- hardware queuing operations (enqueue and dequeue of data) +- hardware buffer pool management + +To transmit a packet the Ethernet driver puts data on a queue and +invokes a DPIO API. For receive, the Ethernet driver registers +a data availability notification callback. To dequeue a packet +a DPIO API is used. +There is typically one DPIO object per physical CPU for optimum +performance, allowing different CPUs to simultaneously enqueue +and dequeue data. + +The DPIO driver operates on behalf of all DPAA2 drivers +active in the kernel-- Ethernet, crypto, compression, +etc. + +Ethernet driver +--------------- +The Ethernet driver is bound to a DPNI and implements the kernel +interfaces needed to connect the DPAA2 network interface to +the network stack. +Each DPNI corresponds to a Linux network interface. + +MAC driver +---------- +An Ethernet PHY is an off-chip, board specific component and is managed +by the appropriate PHY driver via an mdio bus. The MAC driver +plays a role of being a proxy between the PHY driver and the +MC. It does this proxy via the MC commands to a DPMAC object. +If the PHY driver signals a link change, the MAC driver notifies +the MC via a DPMAC command. If a network interface is brought +up or down, the MC notifies the DPMAC driver via an interrupt and +the driver can take appropriate action. diff --git a/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/switch-driver.rst b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/switch-driver.rst new file mode 100644 index 0000000000..8bf411b857 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/switch-driver.rst @@ -0,0 +1,217 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> + +=================== +DPAA2 Switch driver +=================== + +:Copyright: |copy| 2021 NXP + +The DPAA2 Switch driver probes on the Datapath Switch (DPSW) object which can +be instantiated on the following DPAA2 SoCs and their variants: LS2088A and +LX2160A. + +The driver uses the switch device driver model and exposes each switch port as +a network interface, which can be included in a bridge or used as a standalone +interface. Traffic switched between ports is offloaded into the hardware. + +The DPSW can have ports connected to DPNIs or to DPMACs for external access. +:: + + [ethA] [ethB] [ethC] [ethD] [ethE] [ethF] + : : : : : : + : : : : : : + [dpaa2-eth] [dpaa2-eth] [ dpaa2-switch ] + : : : : : : kernel + ============================================================================= + : : : : : : hardware + [DPNI] [DPNI] [============= DPSW =================] + | | | | | | + | ---------- | [DPMAC] [DPMAC] + ------------------------------- | | + | | + [PHY] [PHY] + +Creating an Ethernet Switch +=========================== + +The dpaa2-switch driver probes on DPSW devices found on the fsl-mc bus. These +devices can be either created statically through the boot time configuration +file - DataPath Layout (DPL) - or at runtime using the DPAA2 object APIs +(incorporated already into the restool userspace tool). + +At the moment, the dpaa2-switch driver imposes the following restrictions on +the DPSW object that it will probe: + + * The minimum number of FDBs should be at least equal to the number of switch + interfaces. This is necessary so that separation of switch ports can be + done, ie when not under a bridge, each switch port will have its own FDB. + :: + + fsl_dpaa2_switch dpsw.0: The number of FDBs is lower than the number of ports, cannot probe + + * Both the broadcast and flooding configuration should be per FDB. This + enables the driver to restrict the broadcast and flooding domains of each + FDB depending on the switch ports that are sharing it (aka are under the + same bridge). + :: + + fsl_dpaa2_switch dpsw.0: Flooding domain is not per FDB, cannot probe + fsl_dpaa2_switch dpsw.0: Broadcast domain is not per FDB, cannot probe + + * The control interface of the switch should not be disabled + (DPSW_OPT_CTRL_IF_DIS not passed as a create time option). Without the + control interface, the driver is not capable to provide proper Rx/Tx traffic + support on the switch port netdevices. + :: + + fsl_dpaa2_switch dpsw.0: Control Interface is disabled, cannot probe + +Besides the configuration of the actual DPSW object, the dpaa2-switch driver +will need the following DPAA2 objects: + + * 1 DPMCP - A Management Command Portal object is needed for any interraction + with the MC firmware. + + * 1 DPBP - A Buffer Pool is used for seeding buffers intended for the Rx path + on the control interface. + + * Access to at least one DPIO object (Software Portal) is needed for any + enqueue/dequeue operation to be performed on the control interface queues. + The DPIO object will be shared, no need for a private one. + +Switching features +================== + +The driver supports the configuration of L2 forwarding rules in hardware for +port bridging as well as standalone usage of the independent switch interfaces. + +The hardware is not configurable with respect to VLAN awareness, thus any DPAA2 +switch port should be used only in usecases with a VLAN aware bridge:: + + $ ip link add dev br0 type bridge vlan_filtering 1 + + $ ip link add dev br1 type bridge + $ ip link set dev ethX master br1 + Error: fsl_dpaa2_switch: Cannot join a VLAN-unaware bridge + +Topology and loop detection through STP is supported when ``stp_state 1`` is +used at bridge create :: + + $ ip link add dev br0 type bridge vlan_filtering 1 stp_state 1 + +L2 FDB manipulation (add/delete/dump) is supported. + +HW FDB learning can be configured on each switch port independently through +bridge commands. When the HW learning is disabled, a fast age procedure will be +run and any previously learnt addresses will be removed. +:: + + $ bridge link set dev ethX learning off + $ bridge link set dev ethX learning on + +Restricting the unknown unicast and multicast flooding domain is supported, but +not independently of each other:: + + $ ip link set dev ethX type bridge_slave flood off mcast_flood off + $ ip link set dev ethX type bridge_slave flood off mcast_flood on + Error: fsl_dpaa2_switch: Cannot configure multicast flooding independently of unicast. + +Broadcast flooding on a switch port can be disabled/enabled through the brport sysfs:: + + $ echo 0 > /sys/bus/fsl-mc/devices/dpsw.Y/net/ethX/brport/broadcast_flood + +Offloads +======== + +Routing actions (redirect, trap, drop) +-------------------------------------- + +The DPAA2 switch is able to offload flow-based redirection of packets making +use of ACL tables. Shared filter blocks are supported by sharing a single ACL +table between multiple ports. + +The following flow keys are supported: + + * Ethernet: dst_mac/src_mac + * IPv4: dst_ip/src_ip/ip_proto/tos + * VLAN: vlan_id/vlan_prio/vlan_tpid/vlan_dei + * L4: dst_port/src_port + +Also, the matchall filter can be used to redirect the entire traffic received +on a port. + +As per flow actions, the following are supported: + + * drop + * mirred egress redirect + * trap + +Each ACL entry (filter) can be setup with only one of the listed +actions. + +Example 1: send frames received on eth4 with a SA of 00:01:02:03:04:05 to the +CPU:: + + $ tc qdisc add dev eth4 clsact + $ tc filter add dev eth4 ingress flower src_mac 00:01:02:03:04:05 skip_sw action trap + +Example 2: drop frames received on eth4 with VID 100 and PCP of 3:: + + $ tc filter add dev eth4 ingress protocol 802.1q flower skip_sw vlan_id 100 vlan_prio 3 action drop + +Example 3: redirect all frames received on eth4 to eth1:: + + $ tc filter add dev eth4 ingress matchall action mirred egress redirect dev eth1 + +Example 4: Use a single shared filter block on both eth5 and eth6:: + + $ tc qdisc add dev eth5 ingress_block 1 clsact + $ tc qdisc add dev eth6 ingress_block 1 clsact + $ tc filter add block 1 ingress flower dst_mac 00:01:02:03:04:04 skip_sw \ + action trap + $ tc filter add block 1 ingress protocol ipv4 flower src_ip 192.168.1.1 skip_sw \ + action mirred egress redirect dev eth3 + +Mirroring +~~~~~~~~~ + +The DPAA2 switch supports only per port mirroring and per VLAN mirroring. +Adding mirroring filters in shared blocks is also supported. + +When using the tc-flower classifier with the 802.1q protocol, only the +''vlan_id'' key will be accepted. Mirroring based on any other fields from the +802.1q protocol will be rejected:: + + $ tc qdisc add dev eth8 ingress_block 1 clsact + $ tc filter add block 1 ingress protocol 802.1q flower skip_sw vlan_prio 3 action mirred egress mirror dev eth6 + Error: fsl_dpaa2_switch: Only matching on VLAN ID supported. + We have an error talking to the kernel + +If a mirroring VLAN filter is requested on a port, the VLAN must to be +installed on the switch port in question either using ''bridge'' or by creating +a VLAN upper device if the switch port is used as a standalone interface:: + + $ tc qdisc add dev eth8 ingress_block 1 clsact + $ tc filter add block 1 ingress protocol 802.1q flower skip_sw vlan_id 200 action mirred egress mirror dev eth6 + Error: VLAN must be installed on the switch port. + We have an error talking to the kernel + + $ bridge vlan add vid 200 dev eth8 + $ tc filter add block 1 ingress protocol 802.1q flower skip_sw vlan_id 200 action mirred egress mirror dev eth6 + + $ ip link add link eth8 name eth8.200 type vlan id 200 + $ tc filter add block 1 ingress protocol 802.1q flower skip_sw vlan_id 200 action mirred egress mirror dev eth6 + +Also, it should be noted that the mirrored traffic will be subject to the same +egress restrictions as any other traffic. This means that when a mirrored +packet will reach the mirror port, if the VLAN found in the packet is not +installed on the port it will get dropped. + +The DPAA2 switch supports only a single mirroring destination, thus multiple +mirror rules can be installed but their ''to'' port has to be the same:: + + $ tc filter add block 1 ingress protocol 802.1q flower skip_sw vlan_id 200 action mirred egress mirror dev eth6 + $ tc filter add block 1 ingress protocol 802.1q flower skip_sw vlan_id 100 action mirred egress mirror dev eth7 + Error: fsl_dpaa2_switch: Multiple mirror ports not supported. + We have an error talking to the kernel diff --git a/Documentation/networking/device_drivers/ethernet/freescale/gianfar.rst b/Documentation/networking/device_drivers/ethernet/freescale/gianfar.rst new file mode 100644 index 0000000000..9c4a91d382 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/freescale/gianfar.rst @@ -0,0 +1,51 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=========================== +The Gianfar Ethernet Driver +=========================== + +:Author: Andy Fleming <afleming@freescale.com> +:Updated: 2005-07-28 + + +Checksum Offloading +=================== + +The eTSEC controller (first included in parts from late 2005 like +the 8548) has the ability to perform TCP, UDP, and IP checksums +in hardware. The Linux kernel only offloads the TCP and UDP +checksums (and always performs the pseudo header checksums), so +the driver only supports checksumming for TCP/IP and UDP/IP +packets. Use ethtool to enable or disable this feature for RX +and TX. + +VLAN +==== + +In order to use VLAN, please consult Linux documentation on +configuring VLANs. The gianfar driver supports hardware insertion and +extraction of VLAN headers, but not filtering. Filtering will be +done by the kernel. + +Multicasting +============ + +The gianfar driver supports using the group hash table on the +TSEC (and the extended hash table on the eTSEC) for multicast +filtering. On the eTSEC, the exact-match MAC registers are used +before the hash tables. See Linux documentation on how to join +multicast groups. + +Padding +======= + +The gianfar driver supports padding received frames with 2 bytes +to align the IP header to a 16-byte boundary, when supported by +hardware. + +Ethtool +======= + +The gianfar driver supports the use of ethtool for many +configuration options. You must run ethtool only on currently +open interfaces. See ethtool documentation for details. diff --git a/Documentation/networking/device_drivers/ethernet/google/gve.rst b/Documentation/networking/device_drivers/ethernet/google/gve.rst new file mode 100644 index 0000000000..31d621bca8 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/google/gve.rst @@ -0,0 +1,175 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +============================================================== +Linux kernel driver for Compute Engine Virtual Ethernet (gve): +============================================================== + +Supported Hardware +=================== +The GVE driver binds to a single PCI device id used by the virtual +Ethernet device found in some Compute Engine VMs. + ++--------------+----------+---------+ +|Field | Value | Comments| ++==============+==========+=========+ +|Vendor ID | `0x1AE0` | Google | ++--------------+----------+---------+ +|Device ID | `0x0042` | | ++--------------+----------+---------+ +|Sub-vendor ID | `0x1AE0` | Google | ++--------------+----------+---------+ +|Sub-device ID | `0x0058` | | ++--------------+----------+---------+ +|Revision ID | `0x0` | | ++--------------+----------+---------+ +|Device Class | `0x200` | Ethernet| ++--------------+----------+---------+ + +PCI Bars +======== +The gVNIC PCI device exposes three 32-bit memory BARS: +- Bar0 - Device configuration and status registers. +- Bar1 - MSI-X vector table +- Bar2 - IRQ, RX and TX doorbells + +Device Interactions +=================== +The driver interacts with the device in the following ways: + - Registers + - A block of MMIO registers + - See gve_register.h for more detail + - Admin Queue + - See description below + - Reset + - At any time the device can be reset + - Interrupts + - See supported interrupts below + - Transmit and Receive Queues + - See description below + +Descriptor Formats +------------------ +GVE supports two descriptor formats: GQI and DQO. These two formats have +entirely different descriptors, which will be described below. + +Addressing Mode +------------------ +GVE supports two addressing modes: QPL and RDA. +QPL ("queue-page-list") mode communicates data through a set of +pre-registered pages. + +For RDA ("raw DMA addressing") mode, the set of pages is dynamic. +Therefore, the packet buffers can be anywhere in guest memory. + +Registers +--------- +All registers are MMIO. + +The registers are used for initializing and configuring the device as well as +querying device status in response to management interrupts. + +Endianness +---------- +- Admin Queue messages and registers are all Big Endian. +- GQI descriptors and datapath registers are Big Endian. +- DQO descriptors and datapath registers are Little Endian. + +Admin Queue (AQ) +---------------- +The Admin Queue is a PAGE_SIZE memory block, treated as an array of AQ +commands, used by the driver to issue commands to the device and set up +resources.The driver and the device maintain a count of how many commands +have been submitted and executed. To issue AQ commands, the driver must do +the following (with proper locking): + +1) Copy new commands into next available slots in the AQ array +2) Increment its counter by he number of new commands +3) Write the counter into the GVE_ADMIN_QUEUE_DOORBELL register +4) Poll the ADMIN_QUEUE_EVENT_COUNTER register until it equals + the value written to the doorbell, or until a timeout. + +The device will update the status field in each AQ command reported as +executed through the ADMIN_QUEUE_EVENT_COUNTER register. + +Device Resets +------------- +A device reset is triggered by writing 0x0 to the AQ PFN register. +This causes the device to release all resources allocated by the +driver, including the AQ itself. + +Interrupts +---------- +The following interrupts are supported by the driver: + +Management Interrupt +~~~~~~~~~~~~~~~~~~~~ +The management interrupt is used by the device to tell the driver to +look at the GVE_DEVICE_STATUS register. + +The handler for the management irq simply queues the service task in +the workqueue to check the register and acks the irq. + +Notification Block Interrupts +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +The notification block interrupts are used to tell the driver to poll +the queues associated with that interrupt. + +The handler for these irqs schedule the napi for that block to run +and poll the queues. + +GQI Traffic Queues +------------------ +GQI queues are composed of a descriptor ring and a buffer and are assigned to a +notification block. + +The descriptor rings are power-of-two-sized ring buffers consisting of +fixed-size descriptors. They advance their head pointer using a __be32 +doorbell located in Bar2. The tail pointers are advanced by consuming +descriptors in-order and updating a __be32 counter. Both the doorbell +and the counter overflow to zero. + +Each queue's buffers must be registered in advance with the device as a +queue page list, and packet data can only be put in those pages. + +Transmit +~~~~~~~~ +gve maps the buffers for transmit rings into a FIFO and copies the packets +into the FIFO before sending them to the NIC. + +Receive +~~~~~~~ +The buffers for receive rings are put into a data ring that is the same +length as the descriptor ring and the head and tail pointers advance over +the rings together. + +DQO Traffic Queues +------------------ +- Every TX and RX queue is assigned a notification block. + +- TX and RX buffers queues, which send descriptors to the device, use MMIO + doorbells to notify the device of new descriptors. + +- RX and TX completion queues, which receive descriptors from the device, use a + "generation bit" to know when a descriptor was populated by the device. The + driver initializes all bits with the "current generation". The device will + populate received descriptors with the "next generation" which is inverted + from the current generation. When the ring wraps, the current/next generation + are swapped. + +- It's the driver's responsibility to ensure that the RX and TX completion + queues are not overrun. This can be accomplished by limiting the number of + descriptors posted to HW. + +- TX packets have a 16 bit completion_tag and RX buffers have a 16 bit + buffer_id. These will be returned on the TX completion and RX queues + respectively to let the driver know which packet/buffer was completed. + +Transmit +~~~~~~~~ +A packet's buffers are DMA mapped for the device to access before transmission. +After the packet was successfully transmitted, the buffers are unmapped. + +Receive +~~~~~~~ +The driver posts fixed sized buffers to HW on the RX buffer queue. The packet +received on the associated RX queue may span multiple descriptors. diff --git a/Documentation/networking/device_drivers/ethernet/huawei/hinic.rst b/Documentation/networking/device_drivers/ethernet/huawei/hinic.rst new file mode 100644 index 0000000000..867ac8f4e0 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/huawei/hinic.rst @@ -0,0 +1,128 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================================================ +Linux Kernel Driver for Huawei Intelligent NIC(HiNIC) family +============================================================ + +Overview: +========= +HiNIC is a network interface card for the Data Center Area. + +The driver supports a range of link-speed devices (10GbE, 25GbE, 40GbE, etc.). +The driver supports also a negotiated and extendable feature set. + +Some HiNIC devices support SR-IOV. This driver is used for Physical Function +(PF). + +HiNIC devices support MSI-X interrupt vector for each Tx/Rx queue and +adaptive interrupt moderation. + +HiNIC devices support also various offload features such as checksum offload, +TCP Transmit Segmentation Offload(TSO), Receive-Side Scaling(RSS) and +LRO(Large Receive Offload). + + +Supported PCI vendor ID/device IDs: +=================================== + +19e5:1822 - HiNIC PF + + +Driver Architecture and Source Code: +==================================== + +hinic_dev - Implement a Logical Network device that is independent from +specific HW details about HW data structure formats. + +hinic_hwdev - Implement the HW details of the device and include the components +for accessing the PCI NIC. + +hinic_hwdev contains the following components: +=============================================== + +HW Interface: +============= + +The interface for accessing the pci device (DMA memory and PCI BARs). +(hinic_hw_if.c, hinic_hw_if.h) + +Configuration Status Registers Area that describes the HW Registers on the +configuration and status BAR0. (hinic_hw_csr.h) + +MGMT components: +================ + +Asynchronous Event Queues(AEQs) - The event queues for receiving messages from +the MGMT modules on the cards. (hinic_hw_eqs.c, hinic_hw_eqs.h) + +Application Programmable Interface commands(API CMD) - Interface for sending +MGMT commands to the card. (hinic_hw_api_cmd.c, hinic_hw_api_cmd.h) + +Management (MGMT) - the PF to MGMT channel that uses API CMD for sending MGMT +commands to the card and receives notifications from the MGMT modules on the +card by AEQs. Also set the addresses of the IO CMDQs in HW. +(hinic_hw_mgmt.c, hinic_hw_mgmt.h) + +IO components: +============== + +Completion Event Queues(CEQs) - The completion Event Queues that describe IO +tasks that are finished. (hinic_hw_eqs.c, hinic_hw_eqs.h) + +Work Queues(WQ) - Contain the memory and operations for use by CMD queues and +the Queue Pairs. The WQ is a Memory Block in a Page. The Block contains +pointers to Memory Areas that are the Memory for the Work Queue Elements(WQEs). +(hinic_hw_wq.c, hinic_hw_wq.h) + +Command Queues(CMDQ) - The queues for sending commands for IO management and is +used to set the QPs addresses in HW. The commands completion events are +accumulated on the CEQ that is configured to receive the CMDQ completion events. +(hinic_hw_cmdq.c, hinic_hw_cmdq.h) + +Queue Pairs(QPs) - The HW Receive and Send queues for Receiving and Transmitting +Data. (hinic_hw_qp.c, hinic_hw_qp.h, hinic_hw_qp_ctxt.h) + +IO - de/constructs all the IO components. (hinic_hw_io.c, hinic_hw_io.h) + +HW device: +========== + +HW device - de/constructs the HW Interface, the MGMT components on the +initialization of the driver and the IO components on the case of Interface +UP/DOWN Events. (hinic_hw_dev.c, hinic_hw_dev.h) + + +hinic_dev contains the following components: +=============================================== + +PCI ID table - Contains the supported PCI Vendor/Device IDs. +(hinic_pci_tbl.h) + +Port Commands - Send commands to the HW device for port management +(MAC, Vlan, MTU, ...). (hinic_port.c, hinic_port.h) + +Tx Queues - Logical Tx Queues that use the HW Send Queues for transmit. +The Logical Tx queue is not dependent on the format of the HW Send Queue. +(hinic_tx.c, hinic_tx.h) + +Rx Queues - Logical Rx Queues that use the HW Receive Queues for receive. +The Logical Rx queue is not dependent on the format of the HW Receive Queue. +(hinic_rx.c, hinic_rx.h) + +hinic_dev - de/constructs the Logical Tx and Rx Queues. +(hinic_main.c, hinic_dev.h) + + +Miscellaneous +============= + +Common functions that are used by HW and Logical Device. +(hinic_common.c, hinic_common.h) + + +Support +======= + +If an issue is identified with the released source code on the supported kernel +with a supported adapter, email the specific information related to the issue to +aviad.krawczyk@huawei.com. diff --git a/Documentation/networking/device_drivers/ethernet/index.rst b/Documentation/networking/device_drivers/ethernet/index.rst new file mode 100644 index 0000000000..9827e81608 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/index.rst @@ -0,0 +1,64 @@ +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) + +Ethernet Device Drivers +======================= + +Device drivers for Ethernet and Ethernet-based virtual function devices. + +Contents: + +.. toctree:: + :maxdepth: 2 + + 3com/3c509 + 3com/vortex + amazon/ena + altera/altera_tse + amd/pds_core + amd/pds_vdpa + amd/pds_vfio_pci + aquantia/atlantic + chelsio/cxgb + cirrus/cs89x0 + dlink/dl2k + davicom/dm9000 + dec/dmfe + freescale/dpaa + freescale/dpaa2/index + freescale/gianfar + google/gve + huawei/hinic + intel/e100 + intel/e1000 + intel/e1000e + intel/fm10k + intel/igb + intel/igbvf + intel/ixgbe + intel/ixgbevf + intel/i40e + intel/iavf + intel/ice + marvell/octeontx2 + marvell/octeon_ep + mellanox/mlx5/index + microsoft/netvsc + neterion/s2io + netronome/nfp + pensando/ionic + smsc/smc9 + stmicro/stmmac + ti/cpsw + ti/cpsw_switchdev + ti/am65_nuss_cpsw_switchdev + ti/tlan + toshiba/spider_net + wangxun/txgbe + wangxun/ngbe + +.. only:: subproject and html + + Indices + ======= + + * :ref:`genindex` diff --git a/Documentation/networking/device_drivers/ethernet/intel/e100.rst b/Documentation/networking/device_drivers/ethernet/intel/e100.rst new file mode 100644 index 0000000000..5dee1b53e9 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/intel/e100.rst @@ -0,0 +1,185 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +============================================================= +Linux Base Driver for the Intel(R) PRO/100 Family of Adapters +============================================================= + +June 1, 2018 + +Contents +======== + +- In This Release +- Identifying Your Adapter +- Building and Installation +- Driver Configuration Parameters +- Additional Configurations +- Known Issues +- Support + + +In This Release +=============== + +This file describes the Linux Base Driver for the Intel(R) PRO/100 Family of +Adapters. This driver includes support for Itanium(R)2-based systems. + +For questions related to hardware requirements, refer to the documentation +supplied with your Intel PRO/100 adapter. + +The following features are now available in supported kernels: + - Native VLANs + - Channel Bonding (teaming) + - SNMP + +Channel Bonding documentation can be found in the Linux kernel source: +/Documentation/networking/bonding.rst + + +Identifying Your Adapter +======================== + +For information on how to identify your adapter, and for the latest Intel +network drivers, refer to the Intel Support website: +https://www.intel.com/support + +Driver Configuration Parameters +=============================== + +The default value for each parameter is generally the recommended setting, +unless otherwise noted. + +Rx Descriptors: + Number of receive descriptors. A receive descriptor is a data + structure that describes a receive buffer and its attributes to the network + controller. The data in the descriptor is used by the controller to write + data from the controller to host memory. In the 3.x.x driver the valid range + for this parameter is 64-256. The default value is 256. This parameter can be + changed using the command:: + + ethtool -G eth? rx n + + Where n is the number of desired Rx descriptors. + +Tx Descriptors: + Number of transmit descriptors. A transmit descriptor is a data + structure that describes a transmit buffer and its attributes to the network + controller. The data in the descriptor is used by the controller to read + data from the host memory to the controller. In the 3.x.x driver the valid + range for this parameter is 64-256. The default value is 128. This parameter + can be changed using the command:: + + ethtool -G eth? tx n + + Where n is the number of desired Tx descriptors. + +Speed/Duplex: + The driver auto-negotiates the link speed and duplex settings by + default. The ethtool utility can be used as follows to force speed/duplex.:: + + ethtool -s eth? autoneg off speed {10|100} duplex {full|half} + + NOTE: setting the speed/duplex to incorrect values will cause the link to + fail. + +Event Log Message Level: + The driver uses the message level flag to log events + to syslog. The message level can be set at driver load time. It can also be + set using the command:: + + ethtool -s eth? msglvl n + + +Additional Configurations +========================= + +Configuring the Driver on Different Distributions +------------------------------------------------- + +Configuring a network driver to load properly when the system is started +is distribution dependent. Typically, the configuration process involves +adding an alias line to `/etc/modprobe.d/*.conf` as well as editing other +system startup scripts and/or configuration files. Many popular Linux +distributions ship with tools to make these changes for you. To learn +the proper way to configure a network device for your system, refer to +your distribution documentation. If during this process you are asked +for the driver or module name, the name for the Linux Base Driver for +the Intel PRO/100 Family of Adapters is e100. + +As an example, if you install the e100 driver for two PRO/100 adapters +(eth0 and eth1), add the following to a configuration file in +/etc/modprobe.d/:: + + alias eth0 e100 + alias eth1 e100 + +Viewing Link Messages +--------------------- + +In order to see link messages and other Intel driver information on your +console, you must set the dmesg level up to six. This can be done by +entering the following on the command line before loading the e100 +driver:: + + dmesg -n 6 + +If you wish to see all messages issued by the driver, including debug +messages, set the dmesg level to eight. + +NOTE: This setting is not saved across reboots. + +ethtool +------- + +The driver utilizes the ethtool interface for driver configuration and +diagnostics, as well as displaying statistical information. The ethtool +version 1.6 or later is required for this functionality. + +The latest release of ethtool can be found from +https://www.kernel.org/pub/software/network/ethtool/ + +Enabling Wake on LAN (WoL) +-------------------------- +WoL is provided through the ethtool utility. For instructions on +enabling WoL with ethtool, refer to the ethtool man page. WoL will be +enabled on the system during the next shut down or reboot. For this +driver version, in order to enable WoL, the e100 driver must be loaded +when shutting down or rebooting the system. + +NAPI +---- + +NAPI (Rx polling mode) is supported in the e100 driver. + +See :ref:`Documentation/networking/napi.rst <napi>` for more information. + +Multiple Interfaces on Same Ethernet Broadcast Network +------------------------------------------------------ + +Due to the default ARP behavior on Linux, it is not possible to have one +system on two IP networks in the same Ethernet broadcast domain +(non-partitioned switch) behave as expected. All Ethernet interfaces +will respond to IP traffic for any IP address assigned to the system. +This results in unbalanced receive traffic. + +If you have multiple interfaces in a server, either turn on ARP +filtering by + +(1) entering:: + + echo 1 > /proc/sys/net/ipv4/conf/all/arp_filter + + (this only works if your kernel's version is higher than 2.4.5), or + +(2) installing the interfaces in separate broadcast domains (either + in different switches or in a switch partitioned to VLANs). + + +Support +======= +For general information, go to the Intel support website at: +https://www.intel.com/support/ + +If an issue is identified with the released source code on a supported kernel +with a supported adapter, email the specific information related to the issue +to intel-wired-lan@lists.osuosl.org. diff --git a/Documentation/networking/device_drivers/ethernet/intel/e1000.rst b/Documentation/networking/device_drivers/ethernet/intel/e1000.rst new file mode 100644 index 0000000000..52a7fb9ce8 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/intel/e1000.rst @@ -0,0 +1,458 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +========================================================== +Linux Base Driver for Intel(R) Ethernet Network Connection +========================================================== + +Intel Gigabit Linux driver. +Copyright(c) 1999 - 2013 Intel Corporation. + +Contents +======== + +- Identifying Your Adapter +- Command Line Parameters +- Speed and Duplex Configuration +- Additional Configurations +- Support + +Identifying Your Adapter +======================== + +For more information on how to identify your adapter, go to the Adapter & +Driver ID Guide at: + + http://support.intel.com/support/go/network/adapter/idguide.htm + +For the latest Intel network drivers for Linux, refer to the following +website. In the search field, enter your adapter name or type, or use the +networking link on the left to search for your adapter: + + http://support.intel.com/support/go/network/adapter/home.htm + +Command Line Parameters +======================= + +The default value for each parameter is generally the recommended setting, +unless otherwise noted. + +NOTES: + For more information about the AutoNeg, Duplex, and Speed + parameters, see the "Speed and Duplex Configuration" section in + this document. + + For more information about the InterruptThrottleRate, + RxIntDelay, TxIntDelay, RxAbsIntDelay, and TxAbsIntDelay + parameters, see the application note at: + http://www.intel.com/design/network/applnots/ap450.htm + +AutoNeg +------- + +(Supported only on adapters with copper connections) + +:Valid Range: 0x01-0x0F, 0x20-0x2F +:Default Value: 0x2F + +This parameter is a bit-mask that specifies the speed and duplex settings +advertised by the adapter. When this parameter is used, the Speed and +Duplex parameters must not be specified. + +NOTE: + Refer to the Speed and Duplex section of this readme for more + information on the AutoNeg parameter. + +Duplex +------ + +(Supported only on adapters with copper connections) + +:Valid Range: 0-2 (0=auto-negotiate, 1=half, 2=full) +:Default Value: 0 + +This defines the direction in which data is allowed to flow. Can be +either one or two-directional. If both Duplex and the link partner are +set to auto-negotiate, the board auto-detects the correct duplex. If the +link partner is forced (either full or half), Duplex defaults to half- +duplex. + +FlowControl +----------- + +:Valid Range: 0-3 (0=none, 1=Rx only, 2=Tx only, 3=Rx&Tx) +:Default Value: Reads flow control settings from the EEPROM + +This parameter controls the automatic generation(Tx) and response(Rx) +to Ethernet PAUSE frames. + +InterruptThrottleRate +--------------------- + +(not supported on Intel(R) 82542, 82543 or 82544-based adapters) + +:Valid Range: + 0,1,3,4,100-100000 (0=off, 1=dynamic, 3=dynamic conservative, + 4=simplified balancing) +:Default Value: 3 + +The driver can limit the amount of interrupts per second that the adapter +will generate for incoming packets. It does this by writing a value to the +adapter that is based on the maximum amount of interrupts that the adapter +will generate per second. + +Setting InterruptThrottleRate to a value greater or equal to 100 +will program the adapter to send out a maximum of that many interrupts +per second, even if more packets have come in. This reduces interrupt +load on the system and can lower CPU utilization under heavy load, +but will increase latency as packets are not processed as quickly. + +The default behaviour of the driver previously assumed a static +InterruptThrottleRate value of 8000, providing a good fallback value for +all traffic types,but lacking in small packet performance and latency. +The hardware can handle many more small packets per second however, and +for this reason an adaptive interrupt moderation algorithm was implemented. + +Since 7.3.x, the driver has two adaptive modes (setting 1 or 3) in which +it dynamically adjusts the InterruptThrottleRate value based on the traffic +that it receives. After determining the type of incoming traffic in the last +timeframe, it will adjust the InterruptThrottleRate to an appropriate value +for that traffic. + +The algorithm classifies the incoming traffic every interval into +classes. Once the class is determined, the InterruptThrottleRate value is +adjusted to suit that traffic type the best. There are three classes defined: +"Bulk traffic", for large amounts of packets of normal size; "Low latency", +for small amounts of traffic and/or a significant percentage of small +packets; and "Lowest latency", for almost completely small packets or +minimal traffic. + +In dynamic conservative mode, the InterruptThrottleRate value is set to 4000 +for traffic that falls in class "Bulk traffic". If traffic falls in the "Low +latency" or "Lowest latency" class, the InterruptThrottleRate is increased +stepwise to 20000. This default mode is suitable for most applications. + +For situations where low latency is vital such as cluster or +grid computing, the algorithm can reduce latency even more when +InterruptThrottleRate is set to mode 1. In this mode, which operates +the same as mode 3, the InterruptThrottleRate will be increased stepwise to +70000 for traffic in class "Lowest latency". + +In simplified mode the interrupt rate is based on the ratio of TX and +RX traffic. If the bytes per second rate is approximately equal, the +interrupt rate will drop as low as 2000 interrupts per second. If the +traffic is mostly transmit or mostly receive, the interrupt rate could +be as high as 8000. + +Setting InterruptThrottleRate to 0 turns off any interrupt moderation +and may improve small packet latency, but is generally not suitable +for bulk throughput traffic. + +NOTE: + InterruptThrottleRate takes precedence over the TxAbsIntDelay and + RxAbsIntDelay parameters. In other words, minimizing the receive + and/or transmit absolute delays does not force the controller to + generate more interrupts than what the Interrupt Throttle Rate + allows. + +CAUTION: + If you are using the Intel(R) PRO/1000 CT Network Connection + (controller 82547), setting InterruptThrottleRate to a value + greater than 75,000, may hang (stop transmitting) adapters + under certain network conditions. If this occurs a NETDEV + WATCHDOG message is logged in the system event log. In + addition, the controller is automatically reset, restoring + the network connection. To eliminate the potential for the + hang, ensure that InterruptThrottleRate is set no greater + than 75,000 and is not set to 0. + +NOTE: + When e1000 is loaded with default settings and multiple adapters + are in use simultaneously, the CPU utilization may increase non- + linearly. In order to limit the CPU utilization without impacting + the overall throughput, we recommend that you load the driver as + follows:: + + modprobe e1000 InterruptThrottleRate=3000,3000,3000 + + This sets the InterruptThrottleRate to 3000 interrupts/sec for + the first, second, and third instances of the driver. The range + of 2000 to 3000 interrupts per second works on a majority of + systems and is a good starting point, but the optimal value will + be platform-specific. If CPU utilization is not a concern, use + RX_POLLING (NAPI) and default driver settings. + +RxDescriptors +------------- + +:Valid Range: + - 48-256 for 82542 and 82543-based adapters + - 48-4096 for all other supported adapters +:Default Value: 256 + +This value specifies the number of receive buffer descriptors allocated +by the driver. Increasing this value allows the driver to buffer more +incoming packets, at the expense of increased system memory utilization. + +Each descriptor is 16 bytes. A receive buffer is also allocated for each +descriptor and can be either 2048, 4096, 8192, or 16384 bytes, depending +on the MTU setting. The maximum MTU size is 16110. + +NOTE: + MTU designates the frame size. It only needs to be set for Jumbo + Frames. Depending on the available system resources, the request + for a higher number of receive descriptors may be denied. In this + case, use a lower number. + +RxIntDelay +---------- + +:Valid Range: 0-65535 (0=off) +:Default Value: 0 + +This value delays the generation of receive interrupts in units of 1.024 +microseconds. Receive interrupt reduction can improve CPU efficiency if +properly tuned for specific network traffic. Increasing this value adds +extra latency to frame reception and can end up decreasing the throughput +of TCP traffic. If the system is reporting dropped receives, this value +may be set too high, causing the driver to run out of available receive +descriptors. + +CAUTION: + When setting RxIntDelay to a value other than 0, adapters may + hang (stop transmitting) under certain network conditions. If + this occurs a NETDEV WATCHDOG message is logged in the system + event log. In addition, the controller is automatically reset, + restoring the network connection. To eliminate the potential + for the hang ensure that RxIntDelay is set to 0. + +RxAbsIntDelay +------------- + +(This parameter is supported only on 82540, 82545 and later adapters.) + +:Valid Range: 0-65535 (0=off) +:Default Value: 128 + +This value, in units of 1.024 microseconds, limits the delay in which a +receive interrupt is generated. Useful only if RxIntDelay is non-zero, +this value ensures that an interrupt is generated after the initial +packet is received within the set amount of time. Proper tuning, +along with RxIntDelay, may improve traffic throughput in specific network +conditions. + +Speed +----- + +(This parameter is supported only on adapters with copper connections.) + +:Valid Settings: 0, 10, 100, 1000 +:Default Value: 0 (auto-negotiate at all supported speeds) + +Speed forces the line speed to the specified value in megabits per second +(Mbps). If this parameter is not specified or is set to 0 and the link +partner is set to auto-negotiate, the board will auto-detect the correct +speed. Duplex should also be set when Speed is set to either 10 or 100. + +TxDescriptors +------------- + +:Valid Range: + - 48-256 for 82542 and 82543-based adapters + - 48-4096 for all other supported adapters +:Default Value: 256 + +This value is the number of transmit descriptors allocated by the driver. +Increasing this value allows the driver to queue more transmits. Each +descriptor is 16 bytes. + +NOTE: + Depending on the available system resources, the request for a + higher number of transmit descriptors may be denied. In this case, + use a lower number. + +TxIntDelay +---------- + +:Valid Range: 0-65535 (0=off) +:Default Value: 8 + +This value delays the generation of transmit interrupts in units of +1.024 microseconds. Transmit interrupt reduction can improve CPU +efficiency if properly tuned for specific network traffic. If the +system is reporting dropped transmits, this value may be set too high +causing the driver to run out of available transmit descriptors. + +TxAbsIntDelay +------------- + +(This parameter is supported only on 82540, 82545 and later adapters.) + +:Valid Range: 0-65535 (0=off) +:Default Value: 32 + +This value, in units of 1.024 microseconds, limits the delay in which a +transmit interrupt is generated. Useful only if TxIntDelay is non-zero, +this value ensures that an interrupt is generated after the initial +packet is sent on the wire within the set amount of time. Proper tuning, +along with TxIntDelay, may improve traffic throughput in specific +network conditions. + +XsumRX +------ + +(This parameter is NOT supported on the 82542-based adapter.) + +:Valid Range: 0-1 +:Default Value: 1 + +A value of '1' indicates that the driver should enable IP checksum +offload for received packets (both UDP and TCP) to the adapter hardware. + +Copybreak +--------- + +:Valid Range: 0-xxxxxxx (0=off) +:Default Value: 256 +:Usage: modprobe e1000.ko copybreak=128 + +Driver copies all packets below or equaling this size to a fresh RX +buffer before handing it up the stack. + +This parameter is different than other parameters, in that it is a +single (not 1,1,1 etc.) parameter applied to all driver instances and +it is also available during runtime at +/sys/module/e1000/parameters/copybreak + +SmartPowerDownEnable +-------------------- + +:Valid Range: 0-1 +:Default Value: 0 (disabled) + +Allows PHY to turn off in lower power states. The user can turn off +this parameter in supported chipsets. + +Speed and Duplex Configuration +============================== + +Three keywords are used to control the speed and duplex configuration. +These keywords are Speed, Duplex, and AutoNeg. + +If the board uses a fiber interface, these keywords are ignored, and the +fiber interface board only links at 1000 Mbps full-duplex. + +For copper-based boards, the keywords interact as follows: + +- The default operation is auto-negotiate. The board advertises all + supported speed and duplex combinations, and it links at the highest + common speed and duplex mode IF the link partner is set to auto-negotiate. + +- If Speed = 1000, limited auto-negotiation is enabled and only 1000 Mbps + is advertised (The 1000BaseT spec requires auto-negotiation.) + +- If Speed = 10 or 100, then both Speed and Duplex should be set. Auto- + negotiation is disabled, and the AutoNeg parameter is ignored. Partner + SHOULD also be forced. + +The AutoNeg parameter is used when more control is required over the +auto-negotiation process. It should be used when you wish to control which +speed and duplex combinations are advertised during the auto-negotiation +process. + +The parameter may be specified as either a decimal or hexadecimal value as +determined by the bitmap below. + +============== ====== ====== ======= ======= ====== ====== ======= ====== +Bit position 7 6 5 4 3 2 1 0 +Decimal Value 128 64 32 16 8 4 2 1 +Hex value 80 40 20 10 8 4 2 1 +Speed (Mbps) N/A N/A 1000 N/A 100 100 10 10 +Duplex Full Full Half Full Half +============== ====== ====== ======= ======= ====== ====== ======= ====== + +Some examples of using AutoNeg:: + + modprobe e1000 AutoNeg=0x01 (Restricts autonegotiation to 10 Half) + modprobe e1000 AutoNeg=1 (Same as above) + modprobe e1000 AutoNeg=0x02 (Restricts autonegotiation to 10 Full) + modprobe e1000 AutoNeg=0x03 (Restricts autonegotiation to 10 Half or 10 Full) + modprobe e1000 AutoNeg=0x04 (Restricts autonegotiation to 100 Half) + modprobe e1000 AutoNeg=0x05 (Restricts autonegotiation to 10 Half or 100 + Half) + modprobe e1000 AutoNeg=0x020 (Restricts autonegotiation to 1000 Full) + modprobe e1000 AutoNeg=32 (Same as above) + +Note that when this parameter is used, Speed and Duplex must not be specified. + +If the link partner is forced to a specific speed and duplex, then this +parameter should not be used. Instead, use the Speed and Duplex parameters +previously mentioned to force the adapter to the same speed and duplex. + +Additional Configurations +========================= + +Jumbo Frames +------------ + + Jumbo Frames support is enabled by changing the MTU to a value larger than + the default of 1500. Use the ifconfig command to increase the MTU size. + For example:: + + ifconfig eth<x> mtu 9000 up + + This setting is not saved across reboots. It can be made permanent if + you add:: + + MTU=9000 + + to the file /etc/sysconfig/network-scripts/ifcfg-eth<x>. This example + applies to the Red Hat distributions; other distributions may store this + setting in a different location. + +Notes: + Degradation in throughput performance may be observed in some Jumbo frames + environments. If this is observed, increasing the application's socket buffer + size and/or increasing the /proc/sys/net/ipv4/tcp_*mem entry values may help. + See the specific application manual and /usr/src/linux*/Documentation/ + networking/ip-sysctl.txt for more details. + + - The maximum MTU setting for Jumbo Frames is 16110. This value coincides + with the maximum Jumbo Frames size of 16128. + + - Using Jumbo frames at 10 or 100 Mbps is not supported and may result in + poor performance or loss of link. + + - Adapters based on the Intel(R) 82542 and 82573V/E controller do not + support Jumbo Frames. These correspond to the following product names:: + + Intel(R) PRO/1000 Gigabit Server Adapter + Intel(R) PRO/1000 PM Network Connection + +ethtool +------- + + The driver utilizes the ethtool interface for driver configuration and + diagnostics, as well as displaying statistical information. The ethtool + version 1.6 or later is required for this functionality. + + The latest release of ethtool can be found from + https://www.kernel.org/pub/software/network/ethtool/ + +Enabling Wake on LAN (WoL) +-------------------------- + + WoL is configured through the ethtool utility. + + WoL will be enabled on the system during the next shut down or reboot. + For this driver version, in order to enable WoL, the e1000 driver must be + loaded when shutting down or rebooting the system. + +Support +======= + +For general information, go to the Intel support website at: +http://support.intel.com + +If an issue is identified with the released source code on the supported +kernel with a supported adapter, email the specific information related +to the issue to intel-wired-lan@lists.osuosl.org. diff --git a/Documentation/networking/device_drivers/ethernet/intel/e1000e.rst b/Documentation/networking/device_drivers/ethernet/intel/e1000e.rst new file mode 100644 index 0000000000..d8f810afdd --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/intel/e1000e.rst @@ -0,0 +1,378 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +===================================================== +Linux Driver for Intel(R) Ethernet Network Connection +===================================================== + +Intel Gigabit Linux driver. +Copyright(c) 2008-2018 Intel Corporation. + +Contents +======== + +- Identifying Your Adapter +- Command Line Parameters +- Additional Configurations +- Support + + +Identifying Your Adapter +======================== +For information on how to identify your adapter, and for the latest Intel +network drivers, refer to the Intel Support website: +https://www.intel.com/support + + +Command Line Parameters +======================= +If the driver is built as a module, the following optional parameters are used +by entering them on the command line with the modprobe command using this +syntax:: + + modprobe e1000e [<option>=<VAL1>,<VAL2>,...] + +There needs to be a <VAL#> for each network port in the system supported by +this driver. The values will be applied to each instance, in function order. +For example:: + + modprobe e1000e InterruptThrottleRate=16000,16000 + +In this case, there are two network ports supported by e1000e in the system. +The default value for each parameter is generally the recommended setting, +unless otherwise noted. + +NOTE: A descriptor describes a data buffer and attributes related to the data +buffer. This information is accessed by the hardware. + +InterruptThrottleRate +--------------------- +:Valid Range: 0,1,3,4,100-100000 +:Default Value: 3 + +Interrupt Throttle Rate controls the number of interrupts each interrupt +vector can generate per second. Increasing ITR lowers latency at the cost of +increased CPU utilization, though it may help throughput in some circumstances. + +Setting InterruptThrottleRate to a value greater or equal to 100 +will program the adapter to send out a maximum of that many interrupts +per second, even if more packets have come in. This reduces interrupt +load on the system and can lower CPU utilization under heavy load, +but will increase latency as packets are not processed as quickly. + +The default behaviour of the driver previously assumed a static +InterruptThrottleRate value of 8000, providing a good fallback value for +all traffic types, but lacking in small packet performance and latency. +The hardware can handle many more small packets per second however, and +for this reason an adaptive interrupt moderation algorithm was implemented. + +The driver has two adaptive modes (setting 1 or 3) in which +it dynamically adjusts the InterruptThrottleRate value based on the traffic +that it receives. After determining the type of incoming traffic in the last +timeframe, it will adjust the InterruptThrottleRate to an appropriate value +for that traffic. + +The algorithm classifies the incoming traffic every interval into +classes. Once the class is determined, the InterruptThrottleRate value is +adjusted to suit that traffic type the best. There are three classes defined: +"Bulk traffic", for large amounts of packets of normal size; "Low latency", +for small amounts of traffic and/or a significant percentage of small +packets; and "Lowest latency", for almost completely small packets or +minimal traffic. + + - 0: Off + Turns off any interrupt moderation and may improve small packet latency. + However, this is generally not suitable for bulk throughput traffic due + to the increased CPU utilization of the higher interrupt rate. + - 1: Dynamic mode + This mode attempts to moderate interrupts per vector while maintaining + very low latency. This can sometimes cause extra CPU utilization. If + planning on deploying e1000e in a latency sensitive environment, this + parameter should be considered. + - 3: Dynamic Conservative mode (default) + In dynamic conservative mode, the InterruptThrottleRate value is set to + 4000 for traffic that falls in class "Bulk traffic". If traffic falls in + the "Low latency" or "Lowest latency" class, the InterruptThrottleRate is + increased stepwise to 20000. This default mode is suitable for most + applications. + - 4: Simplified Balancing mode + In simplified mode the interrupt rate is based on the ratio of TX and + RX traffic. If the bytes per second rate is approximately equal, the + interrupt rate will drop as low as 2000 interrupts per second. If the + traffic is mostly transmit or mostly receive, the interrupt rate could + be as high as 8000. + - 100-100000: + Setting InterruptThrottleRate to a value greater or equal to 100 + will program the adapter to send at most that many interrupts per second, + even if more packets have come in. This reduces interrupt load on the + system and can lower CPU utilization under heavy load, but will increase + latency as packets are not processed as quickly. + +NOTE: InterruptThrottleRate takes precedence over the TxAbsIntDelay and +RxAbsIntDelay parameters. In other words, minimizing the receive and/or +transmit absolute delays does not force the controller to generate more +interrupts than what the Interrupt Throttle Rate allows. + +RxIntDelay +---------- +:Valid Range: 0-65535 (0=off) +:Default Value: 0 + +This value delays the generation of receive interrupts in units of 1.024 +microseconds. Receive interrupt reduction can improve CPU efficiency if +properly tuned for specific network traffic. Increasing this value adds extra +latency to frame reception and can end up decreasing the throughput of TCP +traffic. If the system is reporting dropped receives, this value may be set +too high, causing the driver to run out of available receive descriptors. + +CAUTION: When setting RxIntDelay to a value other than 0, adapters may hang +(stop transmitting) under certain network conditions. If this occurs a NETDEV +WATCHDOG message is logged in the system event log. In addition, the +controller is automatically reset, restoring the network connection. To +eliminate the potential for the hang ensure that RxIntDelay is set to 0. + +RxAbsIntDelay +------------- +:Valid Range: 0-65535 (0=off) +:Default Value: 8 + +This value, in units of 1.024 microseconds, limits the delay in which a +receive interrupt is generated. This value ensures that an interrupt is +generated after the initial packet is received within the set amount of time, +which is useful only if RxIntDelay is non-zero. Proper tuning, along with +RxIntDelay, may improve traffic throughput in specific network conditions. + +TxIntDelay +---------- +:Valid Range: 0-65535 (0=off) +:Default Value: 8 + +This value delays the generation of transmit interrupts in units of 1.024 +microseconds. Transmit interrupt reduction can improve CPU efficiency if +properly tuned for specific network traffic. If the system is reporting +dropped transmits, this value may be set too high causing the driver to run +out of available transmit descriptors. + +TxAbsIntDelay +------------- +:Valid Range: 0-65535 (0=off) +:Default Value: 32 + +This value, in units of 1.024 microseconds, limits the delay in which a +transmit interrupt is generated. It is useful only if TxIntDelay is non-zero. +It ensures that an interrupt is generated after the initial Packet is sent on +the wire within the set amount of time. Proper tuning, along with TxIntDelay, +may improve traffic throughput in specific network conditions. + +copybreak +--------- +:Valid Range: 0-xxxxxxx (0=off) +:Default Value: 256 + +The driver copies all packets below or equaling this size to a fresh receive +buffer before handing it up the stack. +This parameter differs from other parameters because it is a single (not 1,1,1 +etc.) parameter applied to all driver instances and it is also available +during runtime at /sys/module/e1000e/parameters/copybreak. + +To use copybreak, type:: + + modprobe e1000e.ko copybreak=128 + +SmartPowerDownEnable +-------------------- +:Valid Range: 0,1 +:Default Value: 0 (disabled) + +Allows the PHY to turn off in lower power states. The user can turn off this +parameter in supported chipsets. + +KumeranLockLoss +--------------- +:Valid Range: 0,1 +:Default Value: 1 (enabled) + +This workaround skips resetting the PHY at shutdown for the initial silicon +releases of ICH8 systems. + +IntMode +------- +:Valid Range: 0-2 +:Default Value: 0 + + +-------+----------------+ + | Value | Interrupt Mode | + +=======+================+ + | 0 | Legacy | + +-------+----------------+ + | 1 | MSI | + +-------+----------------+ + | 2 | MSI-X | + +-------+----------------+ + +IntMode allows load time control over the type of interrupt registered for by +the driver. MSI-X is required for multiple queue support, and some kernels and +combinations of kernel .config options will force a lower level of interrupt +support. + +This command will show different values for each type of interrupt:: + + cat /proc/interrupts + +CrcStripping +------------ +:Valid Range: 0,1 +:Default Value: 1 (enabled) + +Strip the CRC from received packets before sending up the network stack. If +you have a machine with a BMC enabled but cannot receive IPMI traffic after +loading or enabling the driver, try disabling this feature. + +WriteProtectNVM +--------------- +:Valid Range: 0,1 +:Default Value: 1 (enabled) + +If set to 1, configure the hardware to ignore all write/erase cycles to the +GbE region in the ICHx NVM (in order to prevent accidental corruption of the +NVM). This feature can be disabled by setting the parameter to 0 during initial +driver load. + +NOTE: The machine must be power cycled (full off/on) when enabling NVM writes +via setting the parameter to zero. Once the NVM has been locked (via the +parameter at 1 when the driver loads) it cannot be unlocked except via power +cycle. + +Debug +----- +:Valid Range: 0-16 (0=none,...,16=all) +:Default Value: 0 + +This parameter adjusts the level of debug messages displayed in the system logs. + + +Additional Features and Configurations +====================================== + +Jumbo Frames +------------ +Jumbo Frames support is enabled by changing the Maximum Transmission Unit (MTU) +to a value larger than the default value of 1500. + +Use the ifconfig command to increase the MTU size. For example, enter the +following where <x> is the interface number:: + + ifconfig eth<x> mtu 9000 up + +Alternatively, you can use the ip command as follows:: + + ip link set mtu 9000 dev eth<x> + ip link set up dev eth<x> + +This setting is not saved across reboots. The setting change can be made +permanent by adding 'MTU=9000' to the file: + +- For RHEL: /etc/sysconfig/network-scripts/ifcfg-eth<x> +- For SLES: /etc/sysconfig/network/<config_file> + +NOTE: The maximum MTU setting for Jumbo Frames is 8996. This value coincides +with the maximum Jumbo Frames size of 9018 bytes. + +NOTE: Using Jumbo frames at 10 or 100 Mbps is not supported and may result in +poor performance or loss of link. + +NOTE: The following adapters limit Jumbo Frames sized packets to a maximum of +4088 bytes: + + - Intel(R) 82578DM Gigabit Network Connection + - Intel(R) 82577LM Gigabit Network Connection + +The following adapters do not support Jumbo Frames: + + - Intel(R) PRO/1000 Gigabit Server Adapter + - Intel(R) PRO/1000 PM Network Connection + - Intel(R) 82562G 10/100 Network Connection + - Intel(R) 82562G-2 10/100 Network Connection + - Intel(R) 82562GT 10/100 Network Connection + - Intel(R) 82562GT-2 10/100 Network Connection + - Intel(R) 82562V 10/100 Network Connection + - Intel(R) 82562V-2 10/100 Network Connection + - Intel(R) 82566DC Gigabit Network Connection + - Intel(R) 82566DC-2 Gigabit Network Connection + - Intel(R) 82566DM Gigabit Network Connection + - Intel(R) 82566MC Gigabit Network Connection + - Intel(R) 82566MM Gigabit Network Connection + - Intel(R) 82567V-3 Gigabit Network Connection + - Intel(R) 82577LC Gigabit Network Connection + - Intel(R) 82578DC Gigabit Network Connection + +NOTE: Jumbo Frames cannot be configured on an 82579-based Network device if +MACSec is enabled on the system. + + +ethtool +------- +The driver utilizes the ethtool interface for driver configuration and +diagnostics, as well as displaying statistical information. The latest ethtool +version is required for this functionality. Download it at: + +https://www.kernel.org/pub/software/network/ethtool/ + +NOTE: When validating enable/disable tests on some parts (for example, 82578), +it is necessary to add a few seconds between tests when working with ethtool. + + +Speed and Duplex Configuration +------------------------------ +In addressing speed and duplex configuration issues, you need to distinguish +between copper-based adapters and fiber-based adapters. + +In the default mode, an Intel(R) Ethernet Network Adapter using copper +connections will attempt to auto-negotiate with its link partner to determine +the best setting. If the adapter cannot establish link with the link partner +using auto-negotiation, you may need to manually configure the adapter and link +partner to identical settings to establish link and pass packets. This should +only be needed when attempting to link with an older switch that does not +support auto-negotiation or one that has been forced to a specific speed or +duplex mode. Your link partner must match the setting you choose. 1 Gbps speeds +and higher cannot be forced. Use the autonegotiation advertising setting to +manually set devices for 1 Gbps and higher. + +Speed, duplex, and autonegotiation advertising are configured through the +ethtool utility. + +Caution: Only experienced network administrators should force speed and duplex +or change autonegotiation advertising manually. The settings at the switch must +always match the adapter settings. Adapter performance may suffer or your +adapter may not operate if you configure the adapter differently from your +switch. + +An Intel(R) Ethernet Network Adapter using fiber-based connections, however, +will not attempt to auto-negotiate with its link partner since those adapters +operate only in full duplex and only at their native speed. + + +Enabling Wake on LAN (WoL) +-------------------------- +WoL is configured through the ethtool utility. + +WoL will be enabled on the system during the next shut down or reboot. For +this driver version, in order to enable WoL, the e1000e driver must be loaded +prior to shutting down or suspending the system. + +NOTE: Wake on LAN is only supported on port A for the following devices: +- Intel(R) PRO/1000 PT Dual Port Network Connection +- Intel(R) PRO/1000 PT Dual Port Server Connection +- Intel(R) PRO/1000 PT Dual Port Server Adapter +- Intel(R) PRO/1000 PF Dual Port Server Adapter +- Intel(R) PRO/1000 PT Quad Port Server Adapter +- Intel(R) Gigabit PT Quad Port Server ExpressModule + + +Support +======= +For general information, go to the Intel support website at: +https://www.intel.com/support/ + +If an issue is identified with the released source code on a supported kernel +with a supported adapter, email the specific information related to the issue +to intel-wired-lan@lists.osuosl.org. diff --git a/Documentation/networking/device_drivers/ethernet/intel/fm10k.rst b/Documentation/networking/device_drivers/ethernet/intel/fm10k.rst new file mode 100644 index 0000000000..396a2c8c3d --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/intel/fm10k.rst @@ -0,0 +1,137 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +============================================================= +Linux Base Driver for Intel(R) Ethernet Multi-host Controller +============================================================= + +August 20, 2018 +Copyright(c) 2015-2018 Intel Corporation. + +Contents +======== +- Identifying Your Adapter +- Additional Configurations +- Performance Tuning +- Known Issues +- Support + +Identifying Your Adapter +======================== +The driver in this release is compatible with devices based on the Intel(R) +Ethernet Multi-host Controller. + +For information on how to identify your adapter, and for the latest Intel +network drivers, refer to the Intel Support website: +https://www.intel.com/support + + +Flow Control +------------ +The Intel(R) Ethernet Switch Host Interface Driver does not support Flow +Control. It will not send pause frames. This may result in dropped frames. + + +Virtual Functions (VFs) +----------------------- +Use sysfs to enable VFs. +Valid Range: 0-64 + +For example:: + + echo $num_vf_enabled > /sys/class/net/$dev/device/sriov_numvfs //enable VFs + echo 0 > /sys/class/net/$dev/device/sriov_numvfs //disable VFs + +NOTE: Neither the device nor the driver control how VFs are mapped into config +space. Bus layout will vary by operating system. On operating systems that +support it, you can check sysfs to find the mapping. + +NOTE: When SR-IOV mode is enabled, hardware VLAN filtering and VLAN tag +stripping/insertion will remain enabled. Please remove the old VLAN filter +before the new VLAN filter is added. For example:: + + ip link set eth0 vf 0 vlan 100 // set vlan 100 for VF 0 + ip link set eth0 vf 0 vlan 0 // Delete vlan 100 + ip link set eth0 vf 0 vlan 200 // set a new vlan 200 for VF 0 + + +Additional Features and Configurations +====================================== + +Jumbo Frames +------------ +Jumbo Frames support is enabled by changing the Maximum Transmission Unit (MTU) +to a value larger than the default value of 1500. + +Use the ifconfig command to increase the MTU size. For example, enter the +following where <x> is the interface number:: + + ifconfig eth<x> mtu 9000 up + +Alternatively, you can use the ip command as follows:: + + ip link set mtu 9000 dev eth<x> + ip link set up dev eth<x> + +This setting is not saved across reboots. The setting change can be made +permanent by adding 'MTU=9000' to the file: + +- For RHEL: /etc/sysconfig/network-scripts/ifcfg-eth<x> +- For SLES: /etc/sysconfig/network/<config_file> + +NOTE: The maximum MTU setting for Jumbo Frames is 15342. This value coincides +with the maximum Jumbo Frames size of 15364 bytes. + +NOTE: This driver will attempt to use multiple page sized buffers to receive +each jumbo packet. This should help to avoid buffer starvation issues when +allocating receive packets. + + +Generic Receive Offload, aka GRO +-------------------------------- +The driver supports the in-kernel software implementation of GRO. GRO has +shown that by coalescing Rx traffic into larger chunks of data, CPU +utilization can be significantly reduced when under large Rx load. GRO is an +evolution of the previously-used LRO interface. GRO is able to coalesce +other protocols besides TCP. It's also safe to use with configurations that +are problematic for LRO, namely bridging and iSCSI. + + + +Supported ethtool Commands and Options for Filtering +---------------------------------------------------- +-n --show-nfc + Retrieves the receive network flow classification configurations. + +rx-flow-hash tcp4|udp4|ah4|esp4|sctp4|tcp6|udp6|ah6|esp6|sctp6 + Retrieves the hash options for the specified network traffic type. + +-N --config-nfc + Configures the receive network flow classification. + +rx-flow-hash tcp4|udp4|ah4|esp4|sctp4|tcp6|udp6|ah6|esp6|sctp6 m|v|t|s|d|f|n|r + Configures the hash options for the specified network traffic type. + +- udp4: UDP over IPv4 +- udp6: UDP over IPv6 +- f Hash on bytes 0 and 1 of the Layer 4 header of the rx packet. +- n Hash on bytes 2 and 3 of the Layer 4 header of the rx packet. + + +Known Issues/Troubleshooting +============================ + +Enabling SR-IOV in a 64-bit Microsoft Windows Server 2012/R2 guest OS under Linux KVM +------------------------------------------------------------------------------------- +KVM Hypervisor/VMM supports direct assignment of a PCIe device to a VM. This +includes traditional PCIe devices, as well as SR-IOV-capable devices based on +the Intel Ethernet Controller XL710. + + +Support +======= +For general information, go to the Intel support website at: +https://www.intel.com/support/ + +If an issue is identified with the released source code on a supported kernel +with a supported adapter, email the specific information related to the issue +to intel-wired-lan@lists.osuosl.org. diff --git a/Documentation/networking/device_drivers/ethernet/intel/i40e.rst b/Documentation/networking/device_drivers/ethernet/intel/i40e.rst new file mode 100644 index 0000000000..4fbaa1a2d6 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/intel/i40e.rst @@ -0,0 +1,766 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +================================================================= +Linux Base Driver for the Intel(R) Ethernet Controller 700 Series +================================================================= + +Intel 40 Gigabit Linux driver. +Copyright(c) 1999-2018 Intel Corporation. + +Contents +======== + +- Overview +- Identifying Your Adapter +- Intel(R) Ethernet Flow Director +- Additional Configurations +- Known Issues +- Support + + +Driver information can be obtained using ethtool, lspci, and ifconfig. +Instructions on updating ethtool can be found in the section Additional +Configurations later in this document. + +For questions related to hardware requirements, refer to the documentation +supplied with your Intel adapter. All hardware requirements listed apply to use +with Linux. + + +Identifying Your Adapter +======================== +The driver is compatible with devices based on the following: + + * Intel(R) Ethernet Controller X710 + * Intel(R) Ethernet Controller XL710 + * Intel(R) Ethernet Network Connection X722 + * Intel(R) Ethernet Controller XXV710 + +For the best performance, make sure the latest NVM/FW is installed on your +device. + +For information on how to identify your adapter, and for the latest NVM/FW +images and Intel network drivers, refer to the Intel Support website: +https://www.intel.com/support + +SFP+ and QSFP+ Devices +---------------------- +For information about supported media, refer to this document: +https://www.intel.com/content/dam/www/public/us/en/documents/release-notes/xl710-ethernet-controller-feature-matrix.pdf + +NOTE: Some adapters based on the Intel(R) Ethernet Controller 700 Series only +support Intel Ethernet Optics modules. On these adapters, other modules are not +supported and will not function. In all cases Intel recommends using Intel +Ethernet Optics; other modules may function but are not validated by Intel. +Contact Intel for supported media types. + +NOTE: For connections based on Intel(R) Ethernet Controller 700 Series, support +is dependent on your system board. Please see your vendor for details. + +NOTE: In systems that do not have adequate airflow to cool the adapter and +optical modules, you must use high temperature optical modules. + +Virtual Functions (VFs) +----------------------- +Use sysfs to enable VFs. For example:: + + #echo $num_vf_enabled > /sys/class/net/$dev/device/sriov_numvfs #enable VFs + #echo 0 > /sys/class/net/$dev/device/sriov_numvfs #disable VFs + +For example, the following instructions will configure PF eth0 and the first VF +on VLAN 10:: + + $ ip link set dev eth0 vf 0 vlan 10 + +VLAN Tag Packet Steering +------------------------ +Allows you to send all packets with a specific VLAN tag to a particular SR-IOV +virtual function (VF). Further, this feature allows you to designate a +particular VF as trusted, and allows that trusted VF to request selective +promiscuous mode on the Physical Function (PF). + +To set a VF as trusted or untrusted, enter the following command in the +Hypervisor:: + + # ip link set dev eth0 vf 1 trust [on|off] + +Once the VF is designated as trusted, use the following commands in the VM to +set the VF to promiscuous mode. + +:: + + For promiscuous all: + #ip link set eth2 promisc on + Where eth2 is a VF interface in the VM + + For promiscuous Multicast: + #ip link set eth2 allmulticast on + Where eth2 is a VF interface in the VM + +NOTE: By default, the ethtool priv-flag vf-true-promisc-support is set to +"off",meaning that promiscuous mode for the VF will be limited. To set the +promiscuous mode for the VF to true promiscuous and allow the VF to see all +ingress traffic, use the following command:: + + #ethtool -set-priv-flags p261p1 vf-true-promisc-support on + +The vf-true-promisc-support priv-flag does not enable promiscuous mode; rather, +it designates which type of promiscuous mode (limited or true) you will get +when you enable promiscuous mode using the ip link commands above. Note that +this is a global setting that affects the entire device. However,the +vf-true-promisc-support priv-flag is only exposed to the first PF of the +device. The PF remains in limited promiscuous mode (unless it is in MFP mode) +regardless of the vf-true-promisc-support setting. + +Now add a VLAN interface on the VF interface:: + + #ip link add link eth2 name eth2.100 type vlan id 100 + +Note that the order in which you set the VF to promiscuous mode and add the +VLAN interface does not matter (you can do either first). The end result in +this example is that the VF will get all traffic that is tagged with VLAN 100. + +Intel(R) Ethernet Flow Director +------------------------------- +The Intel Ethernet Flow Director performs the following tasks: + +- Directs receive packets according to their flows to different queues. +- Enables tight control on routing a flow in the platform. +- Matches flows and CPU cores for flow affinity. +- Supports multiple parameters for flexible flow classification and load + balancing (in SFP mode only). + +NOTE: The Linux i40e driver supports the following flow types: IPv4, TCPv4, and +UDPv4. For a given flow type, it supports valid combinations of IP addresses +(source or destination) and UDP/TCP ports (source and destination). For +example, you can supply only a source IP address, a source IP address and a +destination port, or any combination of one or more of these four parameters. + +NOTE: The Linux i40e driver allows you to filter traffic based on a +user-defined flexible two-byte pattern and offset by using the ethtool user-def +and mask fields. Only L3 and L4 flow types are supported for user-defined +flexible filters. For a given flow type, you must clear all Intel Ethernet Flow +Director filters before changing the input set (for that flow type). + +To enable or disable the Intel Ethernet Flow Director:: + + # ethtool -K ethX ntuple <on|off> + +When disabling ntuple filters, all the user programmed filters are flushed from +the driver cache and hardware. All needed filters must be re-added when ntuple +is re-enabled. + +To add a filter that directs packet to queue 2, use -U or -N switch:: + + # ethtool -N ethX flow-type tcp4 src-ip 192.168.10.1 dst-ip \ + 192.168.10.2 src-port 2000 dst-port 2001 action 2 [loc 1] + +To set a filter using only the source and destination IP address:: + + # ethtool -N ethX flow-type tcp4 src-ip 192.168.10.1 dst-ip \ + 192.168.10.2 action 2 [loc 1] + +To see the list of filters currently present:: + + # ethtool <-u|-n> ethX + +Application Targeted Routing (ATR) Perfect Filters +-------------------------------------------------- +ATR is enabled by default when the kernel is in multiple transmit queue mode. +An ATR Intel Ethernet Flow Director filter rule is added when a TCP-IP flow +starts and is deleted when the flow ends. When a TCP-IP Intel Ethernet Flow +Director rule is added from ethtool (Sideband filter), ATR is turned off by the +driver. To re-enable ATR, the sideband can be disabled with the ethtool -K +option. For example:: + + ethtool -K [adapter] ntuple [off|on] + +If sideband is re-enabled after ATR is re-enabled, ATR remains enabled until a +TCP-IP flow is added. When all TCP-IP sideband rules are deleted, ATR is +automatically re-enabled. + +Packets that match the ATR rules are counted in fdir_atr_match stats in +ethtool, which also can be used to verify whether ATR rules still exist. + +Sideband Perfect Filters +------------------------ +Sideband Perfect Filters are used to direct traffic that matches specified +characteristics. They are enabled through ethtool's ntuple interface. To add a +new filter use the following command:: + + ethtool -U <device> flow-type <type> src-ip <ip> dst-ip <ip> src-port <port> \ + dst-port <port> action <queue> + +Where: + <device> - the ethernet device to program + <type> - can be ip4, tcp4, udp4, or sctp4 + <ip> - the ip address to match on + <port> - the port number to match on + <queue> - the queue to direct traffic towards (-1 discards matching traffic) + +Use the following command to display all of the active filters:: + + ethtool -u <device> + +Use the following command to delete a filter:: + + ethtool -U <device> delete <N> + +Where <N> is the filter id displayed when printing all the active filters, and +may also have been specified using "loc <N>" when adding the filter. + +The following example matches TCP traffic sent from 192.168.0.1, port 5300, +directed to 192.168.0.5, port 80, and sends it to queue 7:: + + ethtool -U enp130s0 flow-type tcp4 src-ip 192.168.0.1 dst-ip 192.168.0.5 \ + src-port 5300 dst-port 80 action 7 + +For each flow-type, the programmed filters must all have the same matching +input set. For example, issuing the following two commands is acceptable:: + + ethtool -U enp130s0 flow-type ip4 src-ip 192.168.0.1 src-port 5300 action 7 + ethtool -U enp130s0 flow-type ip4 src-ip 192.168.0.5 src-port 55 action 10 + +Issuing the next two commands, however, is not acceptable, since the first +specifies src-ip and the second specifies dst-ip:: + + ethtool -U enp130s0 flow-type ip4 src-ip 192.168.0.1 src-port 5300 action 7 + ethtool -U enp130s0 flow-type ip4 dst-ip 192.168.0.5 src-port 55 action 10 + +The second command will fail with an error. You may program multiple filters +with the same fields, using different values, but, on one device, you may not +program two tcp4 filters with different matching fields. + +Matching on a sub-portion of a field is not supported by the i40e driver, thus +partial mask fields are not supported. + +The driver also supports matching user-defined data within the packet payload. +This flexible data is specified using the "user-def" field of the ethtool +command in the following way: + ++----------------------------+--------------------------+ +| 31 28 24 20 16 | 15 12 8 4 0 | ++----------------------------+--------------------------+ +| offset into packet payload | 2 bytes of flexible data | ++----------------------------+--------------------------+ + +For example, + +:: + + ... user-def 0x4FFFF ... + +tells the filter to look 4 bytes into the payload and match that value against +0xFFFF. The offset is based on the beginning of the payload, and not the +beginning of the packet. Thus + +:: + + flow-type tcp4 ... user-def 0x8BEAF ... + +would match TCP/IPv4 packets which have the value 0xBEAF 8 bytes into the +TCP/IPv4 payload. + +Note that ICMP headers are parsed as 4 bytes of header and 4 bytes of payload. +Thus to match the first byte of the payload, you must actually add 4 bytes to +the offset. Also note that ip4 filters match both ICMP frames as well as raw +(unknown) ip4 frames, where the payload will be the L3 payload of the IP4 frame. + +The maximum offset is 64. The hardware will only read up to 64 bytes of data +from the payload. The offset must be even because the flexible data is 2 bytes +long and must be aligned to byte 0 of the packet payload. + +The user-defined flexible offset is also considered part of the input set and +cannot be programmed separately for multiple filters of the same type. However, +the flexible data is not part of the input set and multiple filters may use the +same offset but match against different data. + +To create filters that direct traffic to a specific Virtual Function, use the +"action" parameter. Specify the action as a 64 bit value, where the lower 32 +bits represents the queue number, while the next 8 bits represent which VF. +Note that 0 is the PF, so the VF identifier is offset by 1. For example:: + + ... action 0x800000002 ... + +specifies to direct traffic to Virtual Function 7 (8 minus 1) into queue 2 of +that VF. + +Note that these filters will not break internal routing rules, and will not +route traffic that otherwise would not have been sent to the specified Virtual +Function. + +Setting the link-down-on-close Private Flag +------------------------------------------- +When the link-down-on-close private flag is set to "on", the port's link will +go down when the interface is brought down using the ifconfig ethX down command. + +Use ethtool to view and set link-down-on-close, as follows:: + + ethtool --show-priv-flags ethX + ethtool --set-priv-flags ethX link-down-on-close [on|off] + +Viewing Link Messages +--------------------- +Link messages will not be displayed to the console if the distribution is +restricting system messages. In order to see network driver link messages on +your console, set dmesg to eight by entering the following:: + + dmesg -n 8 + +NOTE: This setting is not saved across reboots. + +Jumbo Frames +------------ +Jumbo Frames support is enabled by changing the Maximum Transmission Unit (MTU) +to a value larger than the default value of 1500. + +Use the ifconfig command to increase the MTU size. For example, enter the +following where <x> is the interface number:: + + ifconfig eth<x> mtu 9000 up + +Alternatively, you can use the ip command as follows:: + + ip link set mtu 9000 dev eth<x> + ip link set up dev eth<x> + +This setting is not saved across reboots. The setting change can be made +permanent by adding 'MTU=9000' to the file:: + + /etc/sysconfig/network-scripts/ifcfg-eth<x> // for RHEL + /etc/sysconfig/network/<config_file> // for SLES + +NOTE: The maximum MTU setting for Jumbo Frames is 9702. This value coincides +with the maximum Jumbo Frames size of 9728 bytes. + +NOTE: This driver will attempt to use multiple page sized buffers to receive +each jumbo packet. This should help to avoid buffer starvation issues when +allocating receive packets. + +ethtool +------- +The driver utilizes the ethtool interface for driver configuration and +diagnostics, as well as displaying statistical information. The latest ethtool +version is required for this functionality. Download it at: +https://www.kernel.org/pub/software/network/ethtool/ + +Supported ethtool Commands and Options for Filtering +---------------------------------------------------- +-n --show-nfc + Retrieves the receive network flow classification configurations. + +rx-flow-hash tcp4|udp4|ah4|esp4|sctp4|tcp6|udp6|ah6|esp6|sctp6 + Retrieves the hash options for the specified network traffic type. + +-N --config-nfc + Configures the receive network flow classification. + +rx-flow-hash tcp4|udp4|ah4|esp4|sctp4|tcp6|udp6|ah6|esp6|sctp6 m|v|t|s|d|f|n|r... + Configures the hash options for the specified network traffic type. + +udp4 UDP over IPv4 +udp6 UDP over IPv6 + +f Hash on bytes 0 and 1 of the Layer 4 header of the Rx packet. +n Hash on bytes 2 and 3 of the Layer 4 header of the Rx packet. + +Speed and Duplex Configuration +------------------------------ +In addressing speed and duplex configuration issues, you need to distinguish +between copper-based adapters and fiber-based adapters. + +In the default mode, an Intel(R) Ethernet Network Adapter using copper +connections will attempt to auto-negotiate with its link partner to determine +the best setting. If the adapter cannot establish link with the link partner +using auto-negotiation, you may need to manually configure the adapter and link +partner to identical settings to establish link and pass packets. This should +only be needed when attempting to link with an older switch that does not +support auto-negotiation or one that has been forced to a specific speed or +duplex mode. Your link partner must match the setting you choose. 1 Gbps speeds +and higher cannot be forced. Use the autonegotiation advertising setting to +manually set devices for 1 Gbps and higher. + +NOTE: You cannot set the speed for devices based on the Intel(R) Ethernet +Network Adapter XXV710 based devices. + +Speed, duplex, and autonegotiation advertising are configured through the +ethtool utility. + +Caution: Only experienced network administrators should force speed and duplex +or change autonegotiation advertising manually. The settings at the switch must +always match the adapter settings. Adapter performance may suffer or your +adapter may not operate if you configure the adapter differently from your +switch. + +An Intel(R) Ethernet Network Adapter using fiber-based connections, however, +will not attempt to auto-negotiate with its link partner since those adapters +operate only in full duplex and only at their native speed. + +NAPI +---- +NAPI (Rx polling mode) is supported in the i40e driver. + +See :ref:`Documentation/networking/napi.rst <napi>` for more information. + +Flow Control +------------ +Ethernet Flow Control (IEEE 802.3x) can be configured with ethtool to enable +receiving and transmitting pause frames for i40e. When transmit is enabled, +pause frames are generated when the receive packet buffer crosses a predefined +threshold. When receive is enabled, the transmit unit will halt for the time +delay specified when a pause frame is received. + +NOTE: You must have a flow control capable link partner. + +Flow Control is on by default. + +Use ethtool to change the flow control settings. + +To enable or disable Rx or Tx Flow Control:: + + ethtool -A eth? rx <on|off> tx <on|off> + +Note: This command only enables or disables Flow Control if auto-negotiation is +disabled. If auto-negotiation is enabled, this command changes the parameters +used for auto-negotiation with the link partner. + +To enable or disable auto-negotiation:: + + ethtool -s eth? autoneg <on|off> + +Note: Flow Control auto-negotiation is part of link auto-negotiation. Depending +on your device, you may not be able to change the auto-negotiation setting. + +RSS Hash Flow +------------- +Allows you to set the hash bytes per flow type and any combination of one or +more options for Receive Side Scaling (RSS) hash byte configuration. + +:: + + # ethtool -N <dev> rx-flow-hash <type> <option> + +Where <type> is: + tcp4 signifying TCP over IPv4 + udp4 signifying UDP over IPv4 + tcp6 signifying TCP over IPv6 + udp6 signifying UDP over IPv6 +And <option> is one or more of: + s Hash on the IP source address of the Rx packet. + d Hash on the IP destination address of the Rx packet. + f Hash on bytes 0 and 1 of the Layer 4 header of the Rx packet. + n Hash on bytes 2 and 3 of the Layer 4 header of the Rx packet. + +MAC and VLAN anti-spoofing feature +---------------------------------- +When a malicious driver attempts to send a spoofed packet, it is dropped by the +hardware and not transmitted. +NOTE: This feature can be disabled for a specific Virtual Function (VF):: + + ip link set <pf dev> vf <vf id> spoofchk {off|on} + +IEEE 1588 Precision Time Protocol (PTP) Hardware Clock (PHC) +------------------------------------------------------------ +Precision Time Protocol (PTP) is used to synchronize clocks in a computer +network. PTP support varies among Intel devices that support this driver. Use +"ethtool -T <netdev name>" to get a definitive list of PTP capabilities +supported by the device. + +IEEE 802.1ad (QinQ) Support +--------------------------- +The IEEE 802.1ad standard, informally known as QinQ, allows for multiple VLAN +IDs within a single Ethernet frame. VLAN IDs are sometimes referred to as +"tags," and multiple VLAN IDs are thus referred to as a "tag stack." Tag stacks +allow L2 tunneling and the ability to segregate traffic within a particular +VLAN ID, among other uses. + +The following are examples of how to configure 802.1ad (QinQ):: + + ip link add link eth0 eth0.24 type vlan proto 802.1ad id 24 + ip link add link eth0.24 eth0.24.371 type vlan proto 802.1Q id 371 + +Where "24" and "371" are example VLAN IDs. + +NOTES: + Receive checksum offloads, cloud filters, and VLAN acceleration are not + supported for 802.1ad (QinQ) packets. + +VXLAN and GENEVE Overlay HW Offloading +-------------------------------------- +Virtual Extensible LAN (VXLAN) allows you to extend an L2 network over an L3 +network, which may be useful in a virtualized or cloud environment. Some +Intel(R) Ethernet Network devices perform VXLAN processing, offloading it from +the operating system. This reduces CPU utilization. + +VXLAN offloading is controlled by the Tx and Rx checksum offload options +provided by ethtool. That is, if Tx checksum offload is enabled, and the +adapter has the capability, VXLAN offloading is also enabled. + +Support for VXLAN and GENEVE HW offloading is dependent on kernel support of +the HW offloading features. + +Multiple Functions per Port +--------------------------- +Some adapters based on the Intel Ethernet Controller X710/XL710 support +multiple functions on a single physical port. Configure these functions through +the System Setup/BIOS. + +Minimum TX Bandwidth is the guaranteed minimum data transmission bandwidth, as +a percentage of the full physical port link speed, that the partition will +receive. The bandwidth the partition is awarded will never fall below the level +you specify. + +The range for the minimum bandwidth values is: +1 to ((100 minus # of partitions on the physical port) plus 1) +For example, if a physical port has 4 partitions, the range would be: +1 to ((100 - 4) + 1 = 97) + +The Maximum Bandwidth percentage represents the maximum transmit bandwidth +allocated to the partition as a percentage of the full physical port link +speed. The accepted range of values is 1-100. The value is used as a limiter, +should you chose that any one particular function not be able to consume 100% +of a port's bandwidth (should it be available). The sum of all the values for +Maximum Bandwidth is not restricted, because no more than 100% of a port's +bandwidth can ever be used. + +NOTE: X710/XXV710 devices fail to enable Max VFs (64) when Multiple Functions +per Port (MFP) and SR-IOV are enabled. An error from i40e is logged that says +"add vsi failed for VF N, aq_err 16". To workaround the issue, enable less than +64 virtual functions (VFs). + +Data Center Bridging (DCB) +-------------------------- +DCB is a configuration Quality of Service implementation in hardware. It uses +the VLAN priority tag (802.1p) to filter traffic. That means that there are 8 +different priorities that traffic can be filtered into. It also enables +priority flow control (802.1Qbb) which can limit or eliminate the number of +dropped packets during network stress. Bandwidth can be allocated to each of +these priorities, which is enforced at the hardware level (802.1Qaz). + +Adapter firmware implements LLDP and DCBX protocol agents as per 802.1AB and +802.1Qaz respectively. The firmware based DCBX agent runs in willing mode only +and can accept settings from a DCBX capable peer. Software configuration of +DCBX parameters via dcbtool/lldptool are not supported. + +NOTE: Firmware LLDP can be disabled by setting the private flag disable-fw-lldp. + +The i40e driver implements the DCB netlink interface layer to allow user-space +to communicate with the driver and query DCB configuration for the port. + +NOTE: +The kernel assumes that TC0 is available, and will disable Priority Flow +Control (PFC) on the device if TC0 is not available. To fix this, ensure TC0 is +enabled when setting up DCB on your switch. + +Interrupt Rate Limiting +----------------------- +:Valid Range: 0-235 (0=no limit) + +The Intel(R) Ethernet Controller XL710 family supports an interrupt rate +limiting mechanism. The user can control, via ethtool, the number of +microseconds between interrupts. + +Syntax:: + + # ethtool -C ethX rx-usecs-high N + +The range of 0-235 microseconds provides an effective range of 4,310 to 250,000 +interrupts per second. The value of rx-usecs-high can be set independently of +rx-usecs and tx-usecs in the same ethtool command, and is also independent of +the adaptive interrupt moderation algorithm. The underlying hardware supports +granularity in 4-microsecond intervals, so adjacent values may result in the +same interrupt rate. + +One possible use case is the following:: + + # ethtool -C ethX adaptive-rx off adaptive-tx off rx-usecs-high 20 rx-usecs \ + 5 tx-usecs 5 + +The above command would disable adaptive interrupt moderation, and allow a +maximum of 5 microseconds before indicating a receive or transmit was complete. +However, instead of resulting in as many as 200,000 interrupts per second, it +limits total interrupts per second to 50,000 via the rx-usecs-high parameter. + +Performance Optimization +======================== +Driver defaults are meant to fit a wide variety of workloads, but if further +optimization is required we recommend experimenting with the following settings. + +NOTE: For better performance when processing small (64B) frame sizes, try +enabling Hyper threading in the BIOS in order to increase the number of logical +cores in the system and subsequently increase the number of queues available to +the adapter. + +Virtualized Environments +------------------------ +1. Disable XPS on both ends by using the included virt_perf_default script +or by running the following command as root:: + + for file in `ls /sys/class/net/<ethX>/queues/tx-*/xps_cpus`; + do echo 0 > $file; done + +2. Using the appropriate mechanism (vcpupin) in the vm, pin the cpu's to +individual lcpu's, making sure to use a set of cpu's included in the +device's local_cpulist: /sys/class/net/<ethX>/device/local_cpulist. + +3. Configure as many Rx/Tx queues in the VM as available. Do not rely on +the default setting of 1. + + +Non-virtualized Environments +---------------------------- +Pin the adapter's IRQs to specific cores by disabling the irqbalance service +and using the included set_irq_affinity script. Please see the script's help +text for further options. + +- The following settings will distribute the IRQs across all the cores evenly:: + + # scripts/set_irq_affinity -x all <interface1> , [ <interface2>, ... ] + +- The following settings will distribute the IRQs across all the cores that are + local to the adapter (same NUMA node):: + + # scripts/set_irq_affinity -x local <interface1> ,[ <interface2>, ... ] + +For very CPU intensive workloads, we recommend pinning the IRQs to all cores. + +For IP Forwarding: Disable Adaptive ITR and lower Rx and Tx interrupts per +queue using ethtool. + +- Setting rx-usecs and tx-usecs to 125 will limit interrupts to about 8000 + interrupts per second per queue. + +:: + + # ethtool -C <interface> adaptive-rx off adaptive-tx off rx-usecs 125 \ + tx-usecs 125 + +For lower CPU utilization: Disable Adaptive ITR and lower Rx and Tx interrupts +per queue using ethtool. + +- Setting rx-usecs and tx-usecs to 250 will limit interrupts to about 4000 + interrupts per second per queue. + +:: + + # ethtool -C <interface> adaptive-rx off adaptive-tx off rx-usecs 250 \ + tx-usecs 250 + +For lower latency: Disable Adaptive ITR and ITR by setting Rx and Tx to 0 using +ethtool. + +:: + + # ethtool -C <interface> adaptive-rx off adaptive-tx off rx-usecs 0 \ + tx-usecs 0 + +Application Device Queues (ADq) +------------------------------- +Application Device Queues (ADq) allows you to dedicate one or more queues to a +specific application. This can reduce latency for the specified application, +and allow Tx traffic to be rate limited per application. Follow the steps below +to set ADq. + +1. Create traffic classes (TCs). Maximum of 8 TCs can be created per interface. +The shaper bw_rlimit parameter is optional. + +Example: Sets up two tcs, tc0 and tc1, with 16 queues each and max tx rate set +to 1Gbit for tc0 and 3Gbit for tc1. + +:: + + # tc qdisc add dev <interface> root mqprio num_tc 2 map 0 0 0 0 1 1 1 1 + queues 16@0 16@16 hw 1 mode channel shaper bw_rlimit min_rate 1Gbit 2Gbit + max_rate 1Gbit 3Gbit + +map: priority mapping for up to 16 priorities to tcs (e.g. map 0 0 0 0 1 1 1 1 +sets priorities 0-3 to use tc0 and 4-7 to use tc1) + +queues: for each tc, <num queues>@<offset> (e.g. queues 16@0 16@16 assigns +16 queues to tc0 at offset 0 and 16 queues to tc1 at offset 16. Max total +number of queues for all tcs is 64 or number of cores, whichever is lower.) + +hw 1 mode channel: ‘channel’ with ‘hw’ set to 1 is a new new hardware +offload mode in mqprio that makes full use of the mqprio options, the +TCs, the queue configurations, and the QoS parameters. + +shaper bw_rlimit: for each tc, sets minimum and maximum bandwidth rates. +Totals must be equal or less than port speed. + +For example: min_rate 1Gbit 3Gbit: Verify bandwidth limit using network +monitoring tools such as `ifstat` or `sar -n DEV [interval] [number of samples]` + +2. Enable HW TC offload on interface:: + + # ethtool -K <interface> hw-tc-offload on + +3. Apply TCs to ingress (RX) flow of interface:: + + # tc qdisc add dev <interface> ingress + +NOTES: + - Run all tc commands from the iproute2 <pathtoiproute2>/tc/ directory. + - ADq is not compatible with cloud filters. + - Setting up channels via ethtool (ethtool -L) is not supported when the + TCs are configured using mqprio. + - You must have iproute2 latest version + - NVM version 6.01 or later is required. + - ADq cannot be enabled when any the following features are enabled: Data + Center Bridging (DCB), Multiple Functions per Port (MFP), or Sideband + Filters. + - If another driver (for example, DPDK) has set cloud filters, you cannot + enable ADq. + - Tunnel filters are not supported in ADq. If encapsulated packets do + arrive in non-tunnel mode, filtering will be done on the inner headers. + For example, for VXLAN traffic in non-tunnel mode, PCTYPE is identified + as a VXLAN encapsulated packet, outer headers are ignored. Therefore, + inner headers are matched. + - If a TC filter on a PF matches traffic over a VF (on the PF), that + traffic will be routed to the appropriate queue of the PF, and will + not be passed on the VF. Such traffic will end up getting dropped higher + up in the TCP/IP stack as it does not match PF address data. + - If traffic matches multiple TC filters that point to different TCs, + that traffic will be duplicated and sent to all matching TC queues. + The hardware switch mirrors the packet to a VSI list when multiple + filters are matched. + + +Known Issues/Troubleshooting +============================ + +NOTE: 1 Gb devices based on the Intel(R) Ethernet Network Connection X722 do +not support the following features: + + * Data Center Bridging (DCB) + * QOS + * VMQ + * SR-IOV + * Task Encapsulation offload (VXLAN, NVGRE) + * Energy Efficient Ethernet (EEE) + * Auto-media detect + +Unexpected Issues when the device driver and DPDK share a device +---------------------------------------------------------------- +Unexpected issues may result when an i40e device is in multi driver mode and +the kernel driver and DPDK driver are sharing the device. This is because +access to the global NIC resources is not synchronized between multiple +drivers. Any change to the global NIC configuration (writing to a global +register, setting global configuration by AQ, or changing switch modes) will +affect all ports and drivers on the device. Loading DPDK with the +"multi-driver" module parameter may mitigate some of the issues. + +TC0 must be enabled when setting up DCB on a switch +--------------------------------------------------- +The kernel assumes that TC0 is available, and will disable Priority Flow +Control (PFC) on the device if TC0 is not available. To fix this, ensure TC0 is +enabled when setting up DCB on your switch. + + +Support +======= +For general information, go to the Intel support website at: +https://www.intel.com/support/ + +If an issue is identified with the released source code on a supported kernel +with a supported adapter, email the specific information related to the issue +to intel-wired-lan@lists.osuosl.org. diff --git a/Documentation/networking/device_drivers/ethernet/intel/iavf.rst b/Documentation/networking/device_drivers/ethernet/intel/iavf.rst new file mode 100644 index 0000000000..eb926c3bd4 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/intel/iavf.rst @@ -0,0 +1,326 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +================================================================= +Linux Base Driver for Intel(R) Ethernet Adaptive Virtual Function +================================================================= + +Intel Ethernet Adaptive Virtual Function Linux driver. +Copyright(c) 2013-2018 Intel Corporation. + +Contents +======== + +- Overview +- Identifying Your Adapter +- Additional Configurations +- Known Issues/Troubleshooting +- Support + +Overview +======== + +This file describes the iavf Linux Base Driver. This driver was formerly +called i40evf. + +The iavf driver supports the below mentioned virtual function devices and +can only be activated on kernels running the i40e or newer Physical Function +(PF) driver compiled with CONFIG_PCI_IOV. The iavf driver requires +CONFIG_PCI_MSI to be enabled. + +The guest OS loading the iavf driver must support MSI-X interrupts. + +Identifying Your Adapter +======================== + +The driver in this kernel is compatible with devices based on the following: + * Intel(R) XL710 X710 Virtual Function + * Intel(R) X722 Virtual Function + * Intel(R) XXV710 Virtual Function + * Intel(R) Ethernet Adaptive Virtual Function + +For the best performance, make sure the latest NVM/FW is installed on your +device. + +For information on how to identify your adapter, and for the latest NVM/FW +images and Intel network drivers, refer to the Intel Support website: +https://www.intel.com/support + + +Additional Features and Configurations +====================================== + +Viewing Link Messages +--------------------- +Link messages will not be displayed to the console if the distribution is +restricting system messages. In order to see network driver link messages on +your console, set dmesg to eight by entering the following:: + + # dmesg -n 8 + +NOTE: + This setting is not saved across reboots. + +ethtool +------- +The driver utilizes the ethtool interface for driver configuration and +diagnostics, as well as displaying statistical information. The latest ethtool +version is required for this functionality. Download it at: +https://www.kernel.org/pub/software/network/ethtool/ + +Setting VLAN Tag Stripping +-------------------------- +If you have applications that require Virtual Functions (VFs) to receive +packets with VLAN tags, you can disable VLAN tag stripping for the VF. The +Physical Function (PF) processes requests issued from the VF to enable or +disable VLAN tag stripping. Note that if the PF has assigned a VLAN to a VF, +then requests from that VF to set VLAN tag stripping will be ignored. + +To enable/disable VLAN tag stripping for a VF, issue the following command +from inside the VM in which you are running the VF:: + + # ethtool -K <if_name> rxvlan on/off + +or alternatively:: + + # ethtool --offload <if_name> rxvlan on/off + +Adaptive Virtual Function +------------------------- +Adaptive Virtual Function (AVF) allows the virtual function driver, or VF, to +adapt to changing feature sets of the physical function driver (PF) with which +it is associated. This allows system administrators to update a PF without +having to update all the VFs associated with it. All AVFs have a single common +device ID and branding string. + +AVFs have a minimum set of features known as "base mode," but may provide +additional features depending on what features are available in the PF with +which the AVF is associated. The following are base mode features: + +- 4 Queue Pairs (QP) and associated Configuration Status Registers (CSRs) + for Tx/Rx +- i40e descriptors and ring format +- Descriptor write-back completion +- 1 control queue, with i40e descriptors, CSRs and ring format +- 5 MSI-X interrupt vectors and corresponding i40e CSRs +- 1 Interrupt Throttle Rate (ITR) index +- 1 Virtual Station Interface (VSI) per VF +- 1 Traffic Class (TC), TC0 +- Receive Side Scaling (RSS) with 64 entry indirection table and key, + configured through the PF +- 1 unicast MAC address reserved per VF +- 16 MAC address filters for each VF +- Stateless offloads - non-tunneled checksums +- AVF device ID +- HW mailbox is used for VF to PF communications (including on Windows) + +IEEE 802.1ad (QinQ) Support +--------------------------- +The IEEE 802.1ad standard, informally known as QinQ, allows for multiple VLAN +IDs within a single Ethernet frame. VLAN IDs are sometimes referred to as +"tags," and multiple VLAN IDs are thus referred to as a "tag stack." Tag stacks +allow L2 tunneling and the ability to segregate traffic within a particular +VLAN ID, among other uses. + +The following are examples of how to configure 802.1ad (QinQ):: + + # ip link add link eth0 eth0.24 type vlan proto 802.1ad id 24 + # ip link add link eth0.24 eth0.24.371 type vlan proto 802.1Q id 371 + +Where "24" and "371" are example VLAN IDs. + +NOTES: + Receive checksum offloads, cloud filters, and VLAN acceleration are not + supported for 802.1ad (QinQ) packets. + +Application Device Queues (ADq) +------------------------------- +Application Device Queues (ADq) allows you to dedicate one or more queues to a +specific application. This can reduce latency for the specified application, +and allow Tx traffic to be rate limited per application. Follow the steps below +to set ADq. + +Requirements: + +- The sch_mqprio, act_mirred and cls_flower modules must be loaded +- The latest version of iproute2 +- If another driver (for example, DPDK) has set cloud filters, you cannot + enable ADQ +- Depending on the underlying PF device, ADQ cannot be enabled when the + following features are enabled: + + + Data Center Bridging (DCB) + + Multiple Functions per Port (MFP) + + Sideband Filters + +1. Create traffic classes (TCs). Maximum of 8 TCs can be created per interface. +The shaper bw_rlimit parameter is optional. + +Example: Sets up two tcs, tc0 and tc1, with 16 queues each and max tx rate set +to 1Gbit for tc0 and 3Gbit for tc1. + +:: + + tc qdisc add dev <interface> root mqprio num_tc 2 map 0 0 0 0 1 1 1 1 + queues 16@0 16@16 hw 1 mode channel shaper bw_rlimit min_rate 1Gbit 2Gbit + max_rate 1Gbit 3Gbit + +map: priority mapping for up to 16 priorities to tcs (e.g. map 0 0 0 0 1 1 1 1 +sets priorities 0-3 to use tc0 and 4-7 to use tc1) + +queues: for each tc, <num queues>@<offset> (e.g. queues 16@0 16@16 assigns +16 queues to tc0 at offset 0 and 16 queues to tc1 at offset 16. Max total +number of queues for all tcs is 64 or number of cores, whichever is lower.) + +hw 1 mode channel: ‘channel’ with ‘hw’ set to 1 is a new new hardware +offload mode in mqprio that makes full use of the mqprio options, the +TCs, the queue configurations, and the QoS parameters. + +shaper bw_rlimit: for each tc, sets minimum and maximum bandwidth rates. +Totals must be equal or less than port speed. + +For example: min_rate 1Gbit 3Gbit: Verify bandwidth limit using network +monitoring tools such as ``ifstat`` or ``sar -n DEV [interval] [number of samples]`` + +NOTE: + Setting up channels via ethtool (ethtool -L) is not supported when the + TCs are configured using mqprio. + +2. Enable HW TC offload on interface:: + + # ethtool -K <interface> hw-tc-offload on + +3. Apply TCs to ingress (RX) flow of interface:: + + # tc qdisc add dev <interface> ingress + +NOTES: + - Run all tc commands from the iproute2 <pathtoiproute2>/tc/ directory + - ADq is not compatible with cloud filters + - Setting up channels via ethtool (ethtool -L) is not supported when the TCs + are configured using mqprio + - You must have iproute2 latest version + - NVM version 6.01 or later is required + - ADq cannot be enabled when any the following features are enabled: Data + Center Bridging (DCB), Multiple Functions per Port (MFP), or Sideband Filters + - If another driver (for example, DPDK) has set cloud filters, you cannot + enable ADq + - Tunnel filters are not supported in ADq. If encapsulated packets do arrive + in non-tunnel mode, filtering will be done on the inner headers. For example, + for VXLAN traffic in non-tunnel mode, PCTYPE is identified as a VXLAN + encapsulated packet, outer headers are ignored. Therefore, inner headers are + matched. + - If a TC filter on a PF matches traffic over a VF (on the PF), that traffic + will be routed to the appropriate queue of the PF, and will not be passed on + the VF. Such traffic will end up getting dropped higher up in the TCP/IP + stack as it does not match PF address data. + - If traffic matches multiple TC filters that point to different TCs, that + traffic will be duplicated and sent to all matching TC queues. The hardware + switch mirrors the packet to a VSI list when multiple filters are matched. + + +Known Issues/Troubleshooting +============================ + +Bonding fails with VFs bound to an Intel(R) Ethernet Controller 700 series device +--------------------------------------------------------------------------------- +If you bind Virtual Functions (VFs) to an Intel(R) Ethernet Controller 700 +series based device, the VF slaves may fail when they become the active slave. +If the MAC address of the VF is set by the PF (Physical Function) of the +device, when you add a slave, or change the active-backup slave, Linux bonding +tries to sync the backup slave's MAC address to the same MAC address as the +active slave. Linux bonding will fail at this point. This issue will not occur +if the VF's MAC address is not set by the PF. + +Traffic Is Not Being Passed Between VM and Client +------------------------------------------------- +You may not be able to pass traffic between a client system and a +Virtual Machine (VM) running on a separate host if the Virtual Function +(VF, or Virtual NIC) is not in trusted mode and spoof checking is enabled +on the VF. Note that this situation can occur in any combination of client, +host, and guest operating system. For information on how to set the VF to +trusted mode, refer to the section "VLAN Tag Packet Steering" in this +readme document. For information on setting spoof checking, refer to the +section "MAC and VLAN anti-spoofing feature" in this readme document. + +Do not unload port driver if VF with active VM is bound to it +------------------------------------------------------------- +Do not unload a port's driver if a Virtual Function (VF) with an active Virtual +Machine (VM) is bound to it. Doing so will cause the port to appear to hang. +Once the VM shuts down, or otherwise releases the VF, the command will complete. + +Using four traffic classes fails +-------------------------------- +Do not try to reserve more than three traffic classes in the iavf driver. Doing +so will fail to set any traffic classes and will cause the driver to write +errors to stdout. Use a maximum of three queues to avoid this issue. + +Multiple log error messages on iavf driver removal +-------------------------------------------------- +If you have several VFs and you remove the iavf driver, several instances of +the following log errors are written to the log:: + + Unable to send opcode 2 to PF, err I40E_ERR_QUEUE_EMPTY, aq_err ok + Unable to send the message to VF 2 aq_err 12 + ARQ Overflow Error detected + +Virtual machine does not get link +--------------------------------- +If the virtual machine has more than one virtual port assigned to it, and those +virtual ports are bound to different physical ports, you may not get link on +all of the virtual ports. The following command may work around the issue:: + + # ethtool -r <PF> + +Where <PF> is the PF interface in the host, for example: p5p1. You may need to +run the command more than once to get link on all virtual ports. + +MAC address of Virtual Function changes unexpectedly +---------------------------------------------------- +If a Virtual Function's MAC address is not assigned in the host, then the VF +(virtual function) driver will use a random MAC address. This random MAC +address may change each time the VF driver is reloaded. You can assign a static +MAC address in the host machine. This static MAC address will survive +a VF driver reload. + +Driver Buffer Overflow Fix +-------------------------- +The fix to resolve CVE-2016-8105, referenced in Intel SA-00069 +https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00069.html +is included in this and future versions of the driver. + +Multiple Interfaces on Same Ethernet Broadcast Network +------------------------------------------------------ +Due to the default ARP behavior on Linux, it is not possible to have one system +on two IP networks in the same Ethernet broadcast domain (non-partitioned +switch) behave as expected. All Ethernet interfaces will respond to IP traffic +for any IP address assigned to the system. This results in unbalanced receive +traffic. + +If you have multiple interfaces in a server, either turn on ARP filtering by +entering:: + + # echo 1 > /proc/sys/net/ipv4/conf/all/arp_filter + +NOTE: + This setting is not saved across reboots. The configuration change can be + made permanent by adding the following line to the file /etc/sysctl.conf:: + + net.ipv4.conf.all.arp_filter = 1 + +Another alternative is to install the interfaces in separate broadcast domains +(either in different switches or in a switch partitioned to VLANs). + +Rx Page Allocation Errors +------------------------- +'Page allocation failure. order:0' errors may occur under stress. +This is caused by the way the Linux kernel reports this stressed condition. + + +Support +======= +For general information, go to the Intel support website at: +https://support.intel.com + +If an issue is identified with the released source code on the supported kernel +with a supported adapter, email the specific information related to the issue +to intel-wired-lan@lists.osuosl.org. diff --git a/Documentation/networking/device_drivers/ethernet/intel/ice.rst b/Documentation/networking/device_drivers/ethernet/intel/ice.rst new file mode 100644 index 0000000000..e4d065c55e --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/intel/ice.rst @@ -0,0 +1,1021 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +================================================================= +Linux Base Driver for the Intel(R) Ethernet Controller 800 Series +================================================================= + +Intel ice Linux driver. +Copyright(c) 2018-2021 Intel Corporation. + +Contents +======== + +- Overview +- Identifying Your Adapter +- Important Notes +- Additional Features & Configurations +- Performance Optimization + + +The associated Virtual Function (VF) driver for this driver is iavf. + +Driver information can be obtained using ethtool and lspci. + +For questions related to hardware requirements, refer to the documentation +supplied with your Intel adapter. All hardware requirements listed apply to use +with Linux. + +This driver supports XDP (Express Data Path) and AF_XDP zero-copy. Note that +XDP is blocked for frame sizes larger than 3KB. + + +Identifying Your Adapter +======================== +For information on how to identify your adapter, and for the latest Intel +network drivers, refer to the Intel Support website: +https://www.intel.com/support + + +Important Notes +=============== + +Packet drops may occur under receive stress +------------------------------------------- +Devices based on the Intel(R) Ethernet Controller 800 Series are designed to +tolerate a limited amount of system latency during PCIe and DMA transactions. +If these transactions take longer than the tolerated latency, it can impact the +length of time the packets are buffered in the device and associated memory, +which may result in dropped packets. These packets drops typically do not have +a noticeable impact on throughput and performance under standard workloads. + +If these packet drops appear to affect your workload, the following may improve +the situation: + +1) Make sure that your system's physical memory is in a high-performance + configuration, as recommended by the platform vendor. A common + recommendation is for all channels to be populated with a single DIMM + module. +2) In your system's BIOS/UEFI settings, select the "Performance" profile. +3) Your distribution may provide tools like "tuned," which can help tweak + kernel settings to achieve better standard settings for different workloads. + + +Configuring SR-IOV for improved network security +------------------------------------------------ +In a virtualized environment, on Intel(R) Ethernet Network Adapters that +support SR-IOV, the virtual function (VF) may be subject to malicious behavior. +Software-generated layer two frames, like IEEE 802.3x (link flow control), IEEE +802.1Qbb (priority based flow-control), and others of this type, are not +expected and can throttle traffic between the host and the virtual switch, +reducing performance. To resolve this issue, and to ensure isolation from +unintended traffic streams, configure all SR-IOV enabled ports for VLAN tagging +from the administrative interface on the PF. This configuration allows +unexpected, and potentially malicious, frames to be dropped. + +See "Configuring VLAN Tagging on SR-IOV Enabled Adapter Ports" later in this +README for configuration instructions. + + +Do not unload port driver if VF with active VM is bound to it +------------------------------------------------------------- +Do not unload a port's driver if a Virtual Function (VF) with an active Virtual +Machine (VM) is bound to it. Doing so will cause the port to appear to hang. +Once the VM shuts down, or otherwise releases the VF, the command will +complete. + + +Additional Features and Configurations +====================================== + +ethtool +------- +The driver utilizes the ethtool interface for driver configuration and +diagnostics, as well as displaying statistical information. The latest ethtool +version is required for this functionality. Download it at: +https://kernel.org/pub/software/network/ethtool/ + +NOTE: The rx_bytes value of ethtool does not match the rx_bytes value of +Netdev, due to the 4-byte CRC being stripped by the device. The difference +between the two rx_bytes values will be 4 x the number of Rx packets. For +example, if Rx packets are 10 and Netdev (software statistics) displays +rx_bytes as "X", then ethtool (hardware statistics) will display rx_bytes as +"X+40" (4 bytes CRC x 10 packets). + + +Viewing Link Messages +--------------------- +Link messages will not be displayed to the console if the distribution is +restricting system messages. In order to see network driver link messages on +your console, set dmesg to eight by entering the following:: + + # dmesg -n 8 + +NOTE: This setting is not saved across reboots. + + +Dynamic Device Personalization +------------------------------ +Dynamic Device Personalization (DDP) allows you to change the packet processing +pipeline of a device by applying a profile package to the device at runtime. +Profiles can be used to, for example, add support for new protocols, change +existing protocols, or change default settings. DDP profiles can also be rolled +back without rebooting the system. + +The DDP package loads during device initialization. The driver looks for +``intel/ice/ddp/ice.pkg`` in your firmware root (typically ``/lib/firmware/`` +or ``/lib/firmware/updates/``) and checks that it contains a valid DDP package +file. + +NOTE: Your distribution should likely have provided the latest DDP file, but if +ice.pkg is missing, you can find it in the linux-firmware repository or from +intel.com. + +If the driver is unable to load the DDP package, the device will enter Safe +Mode. Safe Mode disables advanced and performance features and supports only +basic traffic and minimal functionality, such as updating the NVM or +downloading a new driver or DDP package. Safe Mode only applies to the affected +physical function and does not impact any other PFs. See the "Intel(R) Ethernet +Adapters and Devices User Guide" for more details on DDP and Safe Mode. + +NOTES: + +- If you encounter issues with the DDP package file, you may need to download + an updated driver or DDP package file. See the log messages for more + information. + +- The ice.pkg file is a symbolic link to the default DDP package file. + +- You cannot update the DDP package if any PF drivers are already loaded. To + overwrite a package, unload all PFs and then reload the driver with the new + package. + +- Only the first loaded PF per device can download a package for that device. + +You can install specific DDP package files for different physical devices in +the same system. To install a specific DDP package file: + +1. Download the DDP package file you want for your device. + +2. Rename the file ice-xxxxxxxxxxxxxxxx.pkg, where 'xxxxxxxxxxxxxxxx' is the + unique 64-bit PCI Express device serial number (in hex) of the device you + want the package downloaded on. The filename must include the complete + serial number (including leading zeros) and be all lowercase. For example, + if the 64-bit serial number is b887a3ffffca0568, then the file name would be + ice-b887a3ffffca0568.pkg. + + To find the serial number from the PCI bus address, you can use the + following command:: + + # lspci -vv -s af:00.0 | grep -i Serial + Capabilities: [150 v1] Device Serial Number b8-87-a3-ff-ff-ca-05-68 + + You can use the following command to format the serial number without the + dashes:: + + # lspci -vv -s af:00.0 | grep -i Serial | awk '{print $7}' | sed s/-//g + b887a3ffffca0568 + +3. Copy the renamed DDP package file to + ``/lib/firmware/updates/intel/ice/ddp/``. If the directory does not yet + exist, create it before copying the file. + +4. Unload all of the PFs on the device. + +5. Reload the driver with the new package. + +NOTE: The presence of a device-specific DDP package file overrides the loading +of the default DDP package file (ice.pkg). + + +Intel(R) Ethernet Flow Director +------------------------------- +The Intel Ethernet Flow Director performs the following tasks: + +- Directs receive packets according to their flows to different queues +- Enables tight control on routing a flow in the platform +- Matches flows and CPU cores for flow affinity + +NOTE: This driver supports the following flow types: + +- IPv4 +- TCPv4 +- UDPv4 +- SCTPv4 +- IPv6 +- TCPv6 +- UDPv6 +- SCTPv6 + +Each flow type supports valid combinations of IP addresses (source or +destination) and UDP/TCP/SCTP ports (source and destination). You can supply +only a source IP address, a source IP address and a destination port, or any +combination of one or more of these four parameters. + +NOTE: This driver allows you to filter traffic based on a user-defined flexible +two-byte pattern and offset by using the ethtool user-def and mask fields. Only +L3 and L4 flow types are supported for user-defined flexible filters. For a +given flow type, you must clear all Intel Ethernet Flow Director filters before +changing the input set (for that flow type). + + +Flow Director Filters +--------------------- +Flow Director filters are used to direct traffic that matches specified +characteristics. They are enabled through ethtool's ntuple interface. To enable +or disable the Intel Ethernet Flow Director and these filters:: + + # ethtool -K <ethX> ntuple <off|on> + +NOTE: When you disable ntuple filters, all the user programmed filters are +flushed from the driver cache and hardware. All needed filters must be re-added +when ntuple is re-enabled. + +To display all of the active filters:: + + # ethtool -u <ethX> + +To add a new filter:: + + # ethtool -U <ethX> flow-type <type> src-ip <ip> [m <ip_mask>] dst-ip <ip> + [m <ip_mask>] src-port <port> [m <port_mask>] dst-port <port> [m <port_mask>] + action <queue> + + Where: + <ethX> - the Ethernet device to program + <type> - can be ip4, tcp4, udp4, sctp4, ip6, tcp6, udp6, sctp6 + <ip> - the IP address to match on + <ip_mask> - the IPv4 address to mask on + NOTE: These filters use inverted masks. + <port> - the port number to match on + <port_mask> - the 16-bit integer for masking + NOTE: These filters use inverted masks. + <queue> - the queue to direct traffic toward (-1 discards the + matched traffic) + +To delete a filter:: + + # ethtool -U <ethX> delete <N> + + Where <N> is the filter ID displayed when printing all the active filters, + and may also have been specified using "loc <N>" when adding the filter. + +EXAMPLES: + +To add a filter that directs packet to queue 2:: + + # ethtool -U <ethX> flow-type tcp4 src-ip 192.168.10.1 dst-ip \ + 192.168.10.2 src-port 2000 dst-port 2001 action 2 [loc 1] + +To set a filter using only the source and destination IP address:: + + # ethtool -U <ethX> flow-type tcp4 src-ip 192.168.10.1 dst-ip \ + 192.168.10.2 action 2 [loc 1] + +To set a filter based on a user-defined pattern and offset:: + + # ethtool -U <ethX> flow-type tcp4 src-ip 192.168.10.1 dst-ip \ + 192.168.10.2 user-def 0x4FFFF action 2 [loc 1] + + where the value of the user-def field contains the offset (4 bytes) and + the pattern (0xffff). + +To match TCP traffic sent from 192.168.0.1, port 5300, directed to 192.168.0.5, +port 80, and then send it to queue 7:: + + # ethtool -U enp130s0 flow-type tcp4 src-ip 192.168.0.1 dst-ip 192.168.0.5 + src-port 5300 dst-port 80 action 7 + +To add a TCPv4 filter with a partial mask for a source IP subnet:: + + # ethtool -U <ethX> flow-type tcp4 src-ip 192.168.0.0 m 0.255.255.255 dst-ip + 192.168.5.12 src-port 12600 dst-port 31 action 12 + +NOTES: + +For each flow-type, the programmed filters must all have the same matching +input set. For example, issuing the following two commands is acceptable:: + + # ethtool -U enp130s0 flow-type ip4 src-ip 192.168.0.1 src-port 5300 action 7 + # ethtool -U enp130s0 flow-type ip4 src-ip 192.168.0.5 src-port 55 action 10 + +Issuing the next two commands, however, is not acceptable, since the first +specifies src-ip and the second specifies dst-ip:: + + # ethtool -U enp130s0 flow-type ip4 src-ip 192.168.0.1 src-port 5300 action 7 + # ethtool -U enp130s0 flow-type ip4 dst-ip 192.168.0.5 src-port 55 action 10 + +The second command will fail with an error. You may program multiple filters +with the same fields, using different values, but, on one device, you may not +program two tcp4 filters with different matching fields. + +The ice driver does not support matching on a subportion of a field, thus +partial mask fields are not supported. + + +Flex Byte Flow Director Filters +------------------------------- +The driver also supports matching user-defined data within the packet payload. +This flexible data is specified using the "user-def" field of the ethtool +command in the following way: + +.. table:: + + ============================== ============================ + ``31 28 24 20 16`` ``15 12 8 4 0`` + ``offset into packet payload`` ``2 bytes of flexible data`` + ============================== ============================ + +For example, + +:: + + ... user-def 0x4FFFF ... + +tells the filter to look 4 bytes into the payload and match that value against +0xFFFF. The offset is based on the beginning of the payload, and not the +beginning of the packet. Thus + +:: + + flow-type tcp4 ... user-def 0x8BEAF ... + +would match TCP/IPv4 packets which have the value 0xBEAF 8 bytes into the +TCP/IPv4 payload. + +Note that ICMP headers are parsed as 4 bytes of header and 4 bytes of payload. +Thus to match the first byte of the payload, you must actually add 4 bytes to +the offset. Also note that ip4 filters match both ICMP frames as well as raw +(unknown) ip4 frames, where the payload will be the L3 payload of the IP4 +frame. + +The maximum offset is 64. The hardware will only read up to 64 bytes of data +from the payload. The offset must be even because the flexible data is 2 bytes +long and must be aligned to byte 0 of the packet payload. + +The user-defined flexible offset is also considered part of the input set and +cannot be programmed separately for multiple filters of the same type. However, +the flexible data is not part of the input set and multiple filters may use the +same offset but match against different data. + + +RSS Hash Flow +------------- +Allows you to set the hash bytes per flow type and any combination of one or +more options for Receive Side Scaling (RSS) hash byte configuration. + +:: + + # ethtool -N <ethX> rx-flow-hash <type> <option> + + Where <type> is: + tcp4 signifying TCP over IPv4 + udp4 signifying UDP over IPv4 + tcp6 signifying TCP over IPv6 + udp6 signifying UDP over IPv6 + And <option> is one or more of: + s Hash on the IP source address of the Rx packet. + d Hash on the IP destination address of the Rx packet. + f Hash on bytes 0 and 1 of the Layer 4 header of the Rx packet. + n Hash on bytes 2 and 3 of the Layer 4 header of the Rx packet. + + +Accelerated Receive Flow Steering (aRFS) +---------------------------------------- +Devices based on the Intel(R) Ethernet Controller 800 Series support +Accelerated Receive Flow Steering (aRFS) on the PF. aRFS is a load-balancing +mechanism that allows you to direct packets to the same CPU where an +application is running or consuming the packets in that flow. + +NOTES: + +- aRFS requires that ntuple filtering is enabled via ethtool. +- aRFS support is limited to the following packet types: + + - TCP over IPv4 and IPv6 + - UDP over IPv4 and IPv6 + - Nonfragmented packets + +- aRFS only supports Flow Director filters, which consist of the + source/destination IP addresses and source/destination ports. +- aRFS and ethtool's ntuple interface both use the device's Flow Director. aRFS + and ntuple features can coexist, but you may encounter unexpected results if + there's a conflict between aRFS and ntuple requests. See "Intel(R) Ethernet + Flow Director" for additional information. + +To set up aRFS: + +1. Enable the Intel Ethernet Flow Director and ntuple filters using ethtool. + +:: + + # ethtool -K <ethX> ntuple on + +2. Set up the number of entries in the global flow table. For example: + +:: + + # NUM_RPS_ENTRIES=16384 + # echo $NUM_RPS_ENTRIES > /proc/sys/net/core/rps_sock_flow_entries + +3. Set up the number of entries in the per-queue flow table. For example: + +:: + + # NUM_RX_QUEUES=64 + # for file in /sys/class/net/$IFACE/queues/rx-*/rps_flow_cnt; do + # echo $(($NUM_RPS_ENTRIES/$NUM_RX_QUEUES)) > $file; + # done + +4. Disable the IRQ balance daemon (this is only a temporary stop of the service + until the next reboot). + +:: + + # systemctl stop irqbalance + +5. Configure the interrupt affinity. + + See ``/Documentation/core-api/irq/irq-affinity.rst`` + + +To disable aRFS using ethtool:: + + # ethtool -K <ethX> ntuple off + +NOTE: This command will disable ntuple filters and clear any aRFS filters in +software and hardware. + +Example Use Case: + +1. Set the server application on the desired CPU (e.g., CPU 4). + +:: + + # taskset -c 4 netserver + +2. Use netperf to route traffic from the client to CPU 4 on the server with + aRFS configured. This example uses TCP over IPv4. + +:: + + # netperf -H <Host IPv4 Address> -t TCP_STREAM + + +Enabling Virtual Functions (VFs) +-------------------------------- +Use sysfs to enable virtual functions (VF). + +For example, you can create 4 VFs as follows:: + + # echo 4 > /sys/class/net/<ethX>/device/sriov_numvfs + +To disable VFs, write 0 to the same file:: + + # echo 0 > /sys/class/net/<ethX>/device/sriov_numvfs + +The maximum number of VFs for the ice driver is 256 total (all ports). To check +how many VFs each PF supports, use the following command:: + + # cat /sys/class/net/<ethX>/device/sriov_totalvfs + +Note: You cannot use SR-IOV when link aggregation (LAG)/bonding is active, and +vice versa. To enforce this, the driver checks for this mutual exclusion. + + +Displaying VF Statistics on the PF +---------------------------------- +Use the following command to display the statistics for the PF and its VFs:: + + # ip -s link show dev <ethX> + +NOTE: The output of this command can be very large due to the maximum number of +possible VFs. + +The PF driver will display a subset of the statistics for the PF and for all +VFs that are configured. The PF will always print a statistics block for each +of the possible VFs, and it will show zero for all unconfigured VFs. + + +Configuring VLAN Tagging on SR-IOV Enabled Adapter Ports +-------------------------------------------------------- +To configure VLAN tagging for the ports on an SR-IOV enabled adapter, use the +following command. The VLAN configuration should be done before the VF driver +is loaded or the VM is booted. The VF is not aware of the VLAN tag being +inserted on transmit and removed on received frames (sometimes called "port +VLAN" mode). + +:: + + # ip link set dev <ethX> vf <id> vlan <vlan id> + +For example, the following will configure PF eth0 and the first VF on VLAN 10:: + + # ip link set dev eth0 vf 0 vlan 10 + + +Enabling a VF link if the port is disconnected +---------------------------------------------- +If the physical function (PF) link is down, you can force link up (from the +host PF) on any virtual functions (VF) bound to the PF. + +For example, to force link up on VF 0 bound to PF eth0:: + + # ip link set eth0 vf 0 state enable + +Note: If the command does not work, it may not be supported by your system. + + +Setting the MAC Address for a VF +-------------------------------- +To change the MAC address for the specified VF:: + + # ip link set <ethX> vf 0 mac <address> + +For example:: + + # ip link set <ethX> vf 0 mac 00:01:02:03:04:05 + +This setting lasts until the PF is reloaded. + +NOTE: Assigning a MAC address for a VF from the host will disable any +subsequent requests to change the MAC address from within the VM. This is a +security feature. The VM is not aware of this restriction, so if this is +attempted in the VM, it will trigger MDD events. + + +Trusted VFs and VF Promiscuous Mode +----------------------------------- +This feature allows you to designate a particular VF as trusted and allows that +trusted VF to request selective promiscuous mode on the Physical Function (PF). + +To set a VF as trusted or untrusted, enter the following command in the +Hypervisor:: + + # ip link set dev <ethX> vf 1 trust [on|off] + +NOTE: It's important to set the VF to trusted before setting promiscuous mode. +If the VM is not trusted, the PF will ignore promiscuous mode requests from the +VF. If the VM becomes trusted after the VF driver is loaded, you must make a +new request to set the VF to promiscuous. + +Once the VF is designated as trusted, use the following commands in the VM to +set the VF to promiscuous mode. + +For promiscuous all:: + + # ip link set <ethX> promisc on + Where <ethX> is a VF interface in the VM + +For promiscuous Multicast:: + + # ip link set <ethX> allmulticast on + Where <ethX> is a VF interface in the VM + +NOTE: By default, the ethtool private flag vf-true-promisc-support is set to +"off," meaning that promiscuous mode for the VF will be limited. To set the +promiscuous mode for the VF to true promiscuous and allow the VF to see all +ingress traffic, use the following command:: + + # ethtool --set-priv-flags <ethX> vf-true-promisc-support on + +The vf-true-promisc-support private flag does not enable promiscuous mode; +rather, it designates which type of promiscuous mode (limited or true) you will +get when you enable promiscuous mode using the ip link commands above. Note +that this is a global setting that affects the entire device. However, the +vf-true-promisc-support private flag is only exposed to the first PF of the +device. The PF remains in limited promiscuous mode regardless of the +vf-true-promisc-support setting. + +Next, add a VLAN interface on the VF interface. For example:: + + # ip link add link eth2 name eth2.100 type vlan id 100 + +Note that the order in which you set the VF to promiscuous mode and add the +VLAN interface does not matter (you can do either first). The result in this +example is that the VF will get all traffic that is tagged with VLAN 100. + + +Malicious Driver Detection (MDD) for VFs +---------------------------------------- +Some Intel Ethernet devices use Malicious Driver Detection (MDD) to detect +malicious traffic from the VF and disable Tx/Rx queues or drop the offending +packet until a VF driver reset occurs. You can view MDD messages in the PF's +system log using the dmesg command. + +- If the PF driver logs MDD events from the VF, confirm that the correct VF + driver is installed. +- To restore functionality, you can manually reload the VF or VM or enable + automatic VF resets. +- When automatic VF resets are enabled, the PF driver will immediately reset + the VF and reenable queues when it detects MDD events on the receive path. +- If automatic VF resets are disabled, the PF will not automatically reset the + VF when it detects MDD events. + +To enable or disable automatic VF resets, use the following command:: + + # ethtool --set-priv-flags <ethX> mdd-auto-reset-vf on|off + + +MAC and VLAN Anti-Spoofing Feature for VFs +------------------------------------------ +When a malicious driver on a Virtual Function (VF) interface attempts to send a +spoofed packet, it is dropped by the hardware and not transmitted. + +NOTE: This feature can be disabled for a specific VF:: + + # ip link set <ethX> vf <vf id> spoofchk {off|on} + + +Jumbo Frames +------------ +Jumbo Frames support is enabled by changing the Maximum Transmission Unit (MTU) +to a value larger than the default value of 1500. + +Use the ifconfig command to increase the MTU size. For example, enter the +following where <ethX> is the interface number:: + + # ifconfig <ethX> mtu 9000 up + +Alternatively, you can use the ip command as follows:: + + # ip link set mtu 9000 dev <ethX> + # ip link set up dev <ethX> + +This setting is not saved across reboots. + + +NOTE: The maximum MTU setting for jumbo frames is 9702. This corresponds to the +maximum jumbo frame size of 9728 bytes. + +NOTE: This driver will attempt to use multiple page sized buffers to receive +each jumbo packet. This should help to avoid buffer starvation issues when +allocating receive packets. + +NOTE: Packet loss may have a greater impact on throughput when you use jumbo +frames. If you observe a drop in performance after enabling jumbo frames, +enabling flow control may mitigate the issue. + + +Speed and Duplex Configuration +------------------------------ +In addressing speed and duplex configuration issues, you need to distinguish +between copper-based adapters and fiber-based adapters. + +In the default mode, an Intel(R) Ethernet Network Adapter using copper +connections will attempt to auto-negotiate with its link partner to determine +the best setting. If the adapter cannot establish link with the link partner +using auto-negotiation, you may need to manually configure the adapter and link +partner to identical settings to establish link and pass packets. This should +only be needed when attempting to link with an older switch that does not +support auto-negotiation or one that has been forced to a specific speed or +duplex mode. Your link partner must match the setting you choose. 1 Gbps speeds +and higher cannot be forced. Use the autonegotiation advertising setting to +manually set devices for 1 Gbps and higher. + +Speed, duplex, and autonegotiation advertising are configured through the +ethtool utility. For the latest version, download and install ethtool from the +following website: + + https://kernel.org/pub/software/network/ethtool/ + +To see the speed configurations your device supports, run the following:: + + # ethtool <ethX> + +Caution: Only experienced network administrators should force speed and duplex +or change autonegotiation advertising manually. The settings at the switch must +always match the adapter settings. Adapter performance may suffer or your +adapter may not operate if you configure the adapter differently from your +switch. + + +Data Center Bridging (DCB) +-------------------------- +NOTE: The kernel assumes that TC0 is available, and will disable Priority Flow +Control (PFC) on the device if TC0 is not available. To fix this, ensure TC0 is +enabled when setting up DCB on your switch. + +DCB is a configuration Quality of Service implementation in hardware. It uses +the VLAN priority tag (802.1p) to filter traffic. That means that there are 8 +different priorities that traffic can be filtered into. It also enables +priority flow control (802.1Qbb) which can limit or eliminate the number of +dropped packets during network stress. Bandwidth can be allocated to each of +these priorities, which is enforced at the hardware level (802.1Qaz). + +DCB is normally configured on the network using the DCBX protocol (802.1Qaz), a +specialization of LLDP (802.1AB). The ice driver supports the following +mutually exclusive variants of DCBX support: + +1) Firmware-based LLDP Agent +2) Software-based LLDP Agent + +In firmware-based mode, firmware intercepts all LLDP traffic and handles DCBX +negotiation transparently for the user. In this mode, the adapter operates in +"willing" DCBX mode, receiving DCB settings from the link partner (typically a +switch). The local user can only query the negotiated DCB configuration. For +information on configuring DCBX parameters on a switch, please consult the +switch manufacturer's documentation. + +In software-based mode, LLDP traffic is forwarded to the network stack and user +space, where a software agent can handle it. In this mode, the adapter can +operate in either "willing" or "nonwilling" DCBX mode and DCB configuration can +be both queried and set locally. This mode requires the FW-based LLDP Agent to +be disabled. + +NOTE: + +- You can enable and disable the firmware-based LLDP Agent using an ethtool + private flag. Refer to the "FW-LLDP (Firmware Link Layer Discovery Protocol)" + section in this README for more information. +- In software-based DCBX mode, you can configure DCB parameters using software + LLDP/DCBX agents that interface with the Linux kernel's DCB Netlink API. We + recommend using OpenLLDP as the DCBX agent when running in software mode. For + more information, see the OpenLLDP man pages and + https://github.com/intel/openlldp. +- The driver implements the DCB netlink interface layer to allow the user space + to communicate with the driver and query DCB configuration for the port. +- iSCSI with DCB is not supported. + + +FW-LLDP (Firmware Link Layer Discovery Protocol) +------------------------------------------------ +Use ethtool to change FW-LLDP settings. The FW-LLDP setting is per port and +persists across boots. + +To enable LLDP:: + + # ethtool --set-priv-flags <ethX> fw-lldp-agent on + +To disable LLDP:: + + # ethtool --set-priv-flags <ethX> fw-lldp-agent off + +To check the current LLDP setting:: + + # ethtool --show-priv-flags <ethX> + +NOTE: You must enable the UEFI HII "LLDP Agent" attribute for this setting to +take effect. If "LLDP AGENT" is set to disabled, you cannot enable it from the +OS. + + +Flow Control +------------ +Ethernet Flow Control (IEEE 802.3x) can be configured with ethtool to enable +receiving and transmitting pause frames for ice. When transmit is enabled, +pause frames are generated when the receive packet buffer crosses a predefined +threshold. When receive is enabled, the transmit unit will halt for the time +delay specified when a pause frame is received. + +NOTE: You must have a flow control capable link partner. + +Flow Control is disabled by default. + +Use ethtool to change the flow control settings. + +To enable or disable Rx or Tx Flow Control:: + + # ethtool -A <ethX> rx <on|off> tx <on|off> + +Note: This command only enables or disables Flow Control if auto-negotiation is +disabled. If auto-negotiation is enabled, this command changes the parameters +used for auto-negotiation with the link partner. + +Note: Flow Control auto-negotiation is part of link auto-negotiation. Depending +on your device, you may not be able to change the auto-negotiation setting. + +NOTE: + +- The ice driver requires flow control on both the port and link partner. If + flow control is disabled on one of the sides, the port may appear to hang on + heavy traffic. +- You may encounter issues with link-level flow control (LFC) after disabling + DCB. The LFC status may show as enabled but traffic is not paused. To resolve + this issue, disable and reenable LFC using ethtool:: + + # ethtool -A <ethX> rx off tx off + # ethtool -A <ethX> rx on tx on + + +NAPI +---- + +This driver supports NAPI (Rx polling mode). + +See :ref:`Documentation/networking/napi.rst <napi>` for more information. + +MACVLAN +------- +This driver supports MACVLAN. Kernel support for MACVLAN can be tested by +checking if the MACVLAN driver is loaded. You can run 'lsmod | grep macvlan' to +see if the MACVLAN driver is loaded or run 'modprobe macvlan' to try to load +the MACVLAN driver. + +NOTE: + +- In passthru mode, you can only set up one MACVLAN device. It will inherit the + MAC address of the underlying PF (Physical Function) device. + + +IEEE 802.1ad (QinQ) Support +--------------------------- +The IEEE 802.1ad standard, informally known as QinQ, allows for multiple VLAN +IDs within a single Ethernet frame. VLAN IDs are sometimes referred to as +"tags," and multiple VLAN IDs are thus referred to as a "tag stack." Tag stacks +allow L2 tunneling and the ability to segregate traffic within a particular +VLAN ID, among other uses. + +NOTES: + +- Receive checksum offloads and VLAN acceleration are not supported for 802.1ad + (QinQ) packets. + +- 0x88A8 traffic will not be received unless VLAN stripping is disabled with + the following command:: + + # ethtool -K <ethX> rxvlan off + +- 0x88A8/0x8100 double VLANs cannot be used with 0x8100 or 0x8100/0x8100 VLANS + configured on the same port. 0x88a8/0x8100 traffic will not be received if + 0x8100 VLANs are configured. + +- The VF can only transmit 0x88A8/0x8100 (i.e., 802.1ad/802.1Q) traffic if: + + 1) The VF is not assigned a port VLAN. + 2) spoofchk is disabled from the PF. If you enable spoofchk, the VF will + not transmit 0x88A8/0x8100 traffic. + +- The VF may not receive all network traffic based on the Inner VLAN header + when VF true promiscuous mode (vf-true-promisc-support) and double VLANs are + enabled in SR-IOV mode. + +The following are examples of how to configure 802.1ad (QinQ):: + + # ip link add link eth0 eth0.24 type vlan proto 802.1ad id 24 + # ip link add link eth0.24 eth0.24.371 type vlan proto 802.1Q id 371 + + Where "24" and "371" are example VLAN IDs. + + +Tunnel/Overlay Stateless Offloads +--------------------------------- +Supported tunnels and overlays include VXLAN, GENEVE, and others depending on +hardware and software configuration. Stateless offloads are enabled by default. + +To view the current state of all offloads:: + + # ethtool -k <ethX> + + +UDP Segmentation Offload +------------------------ +Allows the adapter to offload transmit segmentation of UDP packets with +payloads up to 64K into valid Ethernet frames. Because the adapter hardware is +able to complete data segmentation much faster than operating system software, +this feature may improve transmission performance. +In addition, the adapter may use fewer CPU resources. + +NOTE: + +- The application sending UDP packets must support UDP segmentation offload. + +To enable/disable UDP Segmentation Offload, issue the following command:: + + # ethtool -K <ethX> tx-udp-segmentation [off|on] + + +GNSS module +----------- +Requires kernel compiled with CONFIG_GNSS=y or CONFIG_GNSS=m. +Allows user to read messages from the GNSS hardware module and write supported +commands. If the module is physically present, a GNSS device is spawned: +``/dev/gnss<id>``. +The protocol of write command is dependent on the GNSS hardware module as the +driver writes raw bytes by the GNSS object to the receiver through i2c. Please +refer to the hardware GNSS module documentation for configuration details. + + +Performance Optimization +======================== +Driver defaults are meant to fit a wide variety of workloads, but if further +optimization is required, we recommend experimenting with the following +settings. + + +Rx Descriptor Ring Size +----------------------- +To reduce the number of Rx packet discards, increase the number of Rx +descriptors for each Rx ring using ethtool. + + Check if the interface is dropping Rx packets due to buffers being full + (rx_dropped.nic can mean that there is no PCIe bandwidth):: + + # ethtool -S <ethX> | grep "rx_dropped" + + If the previous command shows drops on queues, it may help to increase + the number of descriptors using 'ethtool -G':: + + # ethtool -G <ethX> rx <N> + Where <N> is the desired number of ring entries/descriptors + + This can provide temporary buffering for issues that create latency while + the CPUs process descriptors. + + +Interrupt Rate Limiting +----------------------- +This driver supports an adaptive interrupt throttle rate (ITR) mechanism that +is tuned for general workloads. The user can customize the interrupt rate +control for specific workloads, via ethtool, adjusting the number of +microseconds between interrupts. + +To set the interrupt rate manually, you must disable adaptive mode:: + + # ethtool -C <ethX> adaptive-rx off adaptive-tx off + +For lower CPU utilization: + + Disable adaptive ITR and lower Rx and Tx interrupts. The examples below + affect every queue of the specified interface. + + Setting rx-usecs and tx-usecs to 80 will limit interrupts to about + 12,500 interrupts per second per queue:: + + # ethtool -C <ethX> adaptive-rx off adaptive-tx off rx-usecs 80 tx-usecs 80 + +For reduced latency: + + Disable adaptive ITR and ITR by setting rx-usecs and tx-usecs to 0 + using ethtool:: + + # ethtool -C <ethX> adaptive-rx off adaptive-tx off rx-usecs 0 tx-usecs 0 + +Per-queue interrupt rate settings: + + The following examples are for queues 1 and 3, but you can adjust other + queues. + + To disable Rx adaptive ITR and set static Rx ITR to 10 microseconds or + about 100,000 interrupts/second, for queues 1 and 3:: + + # ethtool --per-queue <ethX> queue_mask 0xa --coalesce adaptive-rx off + rx-usecs 10 + + To show the current coalesce settings for queues 1 and 3:: + + # ethtool --per-queue <ethX> queue_mask 0xa --show-coalesce + +Bounding interrupt rates using rx-usecs-high: + + :Valid Range: 0-236 (0=no limit) + + The range of 0-236 microseconds provides an effective range of 4,237 to + 250,000 interrupts per second. The value of rx-usecs-high can be set + independently of rx-usecs and tx-usecs in the same ethtool command, and is + also independent of the adaptive interrupt moderation algorithm. The + underlying hardware supports granularity in 4-microsecond intervals, so + adjacent values may result in the same interrupt rate. + + The following command would disable adaptive interrupt moderation, and allow + a maximum of 5 microseconds before indicating a receive or transmit was + complete. However, instead of resulting in as many as 200,000 interrupts per + second, it limits total interrupts per second to 50,000 via the rx-usecs-high + parameter. + + :: + + # ethtool -C <ethX> adaptive-rx off adaptive-tx off rx-usecs-high 20 + rx-usecs 5 tx-usecs 5 + + +Virtualized Environments +------------------------ +In addition to the other suggestions in this section, the following may be +helpful to optimize performance in VMs. + + Using the appropriate mechanism (vcpupin) in the VM, pin the CPUs to + individual LCPUs, making sure to use a set of CPUs included in the + device's local_cpulist: ``/sys/class/net/<ethX>/device/local_cpulist``. + + Configure as many Rx/Tx queues in the VM as available. (See the iavf driver + documentation for the number of queues supported.) For example:: + + # ethtool -L <virt_interface> rx <max> tx <max> + + +Support +======= +For general information, go to the Intel support website at: +https://www.intel.com/support/ + +If an issue is identified with the released source code on a supported kernel +with a supported adapter, email the specific information related to the issue +to intel-wired-lan@lists.osuosl.org. + + +Trademarks +========== +Intel is a trademark or registered trademark of Intel Corporation or its +subsidiaries in the United States and/or other countries. + +* Other names and brands may be claimed as the property of others. diff --git a/Documentation/networking/device_drivers/ethernet/intel/igb.rst b/Documentation/networking/device_drivers/ethernet/intel/igb.rst new file mode 100644 index 0000000000..fbd590b6a0 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/intel/igb.rst @@ -0,0 +1,208 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +========================================================== +Linux Base Driver for Intel(R) Ethernet Network Connection +========================================================== + +Intel Gigabit Linux driver. +Copyright(c) 1999-2018 Intel Corporation. + +Contents +======== + +- Identifying Your Adapter +- Command Line Parameters +- Additional Configurations +- Support + + +Identifying Your Adapter +======================== +For information on how to identify your adapter, and for the latest Intel +network drivers, refer to the Intel Support website: +https://www.intel.com/support + + +Command Line Parameters +======================== +If the driver is built as a module, the following optional parameters are used +by entering them on the command line with the modprobe command using this +syntax:: + + modprobe igb [<option>=<VAL1>,<VAL2>,...] + +There needs to be a <VAL#> for each network port in the system supported by +this driver. The values will be applied to each instance, in function order. +For example:: + + modprobe igb max_vfs=2,4 + +In this case, there are two network ports supported by igb in the system. + +NOTE: A descriptor describes a data buffer and attributes related to the data +buffer. This information is accessed by the hardware. + +max_vfs +------- +:Valid Range: 0-7 + +This parameter adds support for SR-IOV. It causes the driver to spawn up to +max_vfs worth of virtual functions. If the value is greater than 0 it will +also force the VMDq parameter to be 1 or more. + +The parameters for the driver are referenced by position. Thus, if you have a +dual port adapter, or more than one adapter in your system, and want N virtual +functions per port, you must specify a number for each port with each parameter +separated by a comma. For example:: + + modprobe igb max_vfs=4 + +This will spawn 4 VFs on the first port. + +:: + + modprobe igb max_vfs=2,4 + +This will spawn 2 VFs on the first port and 4 VFs on the second port. + +NOTE: Caution must be used in loading the driver with these parameters. +Depending on your system configuration, number of slots, etc., it is impossible +to predict in all cases where the positions would be on the command line. + +NOTE: Neither the device nor the driver control how VFs are mapped into config +space. Bus layout will vary by operating system. On operating systems that +support it, you can check sysfs to find the mapping. + +NOTE: When either SR-IOV mode or VMDq mode is enabled, hardware VLAN filtering +and VLAN tag stripping/insertion will remain enabled. Please remove the old +VLAN filter before the new VLAN filter is added. For example:: + + ip link set eth0 vf 0 vlan 100 // set vlan 100 for VF 0 + ip link set eth0 vf 0 vlan 0 // Delete vlan 100 + ip link set eth0 vf 0 vlan 200 // set a new vlan 200 for VF 0 + +Debug +----- +:Valid Range: 0-16 (0=none,...,16=all) +:Default Value: 0 + +This parameter adjusts the level debug messages displayed in the system logs. + + +Additional Features and Configurations +====================================== + +Jumbo Frames +------------ +Jumbo Frames support is enabled by changing the Maximum Transmission Unit (MTU) +to a value larger than the default value of 1500. + +Use the ifconfig command to increase the MTU size. For example, enter the +following where <x> is the interface number:: + + ifconfig eth<x> mtu 9000 up + +Alternatively, you can use the ip command as follows:: + + ip link set mtu 9000 dev eth<x> + ip link set up dev eth<x> + +This setting is not saved across reboots. The setting change can be made +permanent by adding 'MTU=9000' to the file: + +- For RHEL: /etc/sysconfig/network-scripts/ifcfg-eth<x> +- For SLES: /etc/sysconfig/network/<config_file> + +NOTE: The maximum MTU setting for Jumbo Frames is 9216. This value coincides +with the maximum Jumbo Frames size of 9234 bytes. + +NOTE: Using Jumbo frames at 10 or 100 Mbps is not supported and may result in +poor performance or loss of link. + + +ethtool +------- +The driver utilizes the ethtool interface for driver configuration and +diagnostics, as well as displaying statistical information. The latest ethtool +version is required for this functionality. Download it at: + +https://www.kernel.org/pub/software/network/ethtool/ + + +Enabling Wake on LAN (WoL) +-------------------------- +WoL is configured through the ethtool utility. + +WoL will be enabled on the system during the next shut down or reboot. For +this driver version, in order to enable WoL, the igb driver must be loaded +prior to shutting down or suspending the system. + +NOTE: Wake on LAN is only supported on port A of multi-port devices. Also +Wake On LAN is not supported for the following device: +- Intel(R) Gigabit VT Quad Port Server Adapter + + +Multiqueue +---------- +In this mode, a separate MSI-X vector is allocated for each queue and one for +"other" interrupts such as link status change and errors. All interrupts are +throttled via interrupt moderation. Interrupt moderation must be used to avoid +interrupt storms while the driver is processing one interrupt. The moderation +value should be at least as large as the expected time for the driver to +process an interrupt. Multiqueue is off by default. + +REQUIREMENTS: MSI-X support is required for Multiqueue. If MSI-X is not found, +the system will fallback to MSI or to Legacy interrupts. This driver supports +receive multiqueue on all kernels that support MSI-X. + +NOTE: On some kernels a reboot is required to switch between single queue mode +and multiqueue mode or vice-versa. + + +MAC and VLAN anti-spoofing feature +---------------------------------- +When a malicious driver attempts to send a spoofed packet, it is dropped by the +hardware and not transmitted. + +An interrupt is sent to the PF driver notifying it of the spoof attempt. When a +spoofed packet is detected, the PF driver will send the following message to +the system log (displayed by the "dmesg" command): +Spoof event(s) detected on VF(n), where n = the VF that attempted to do the +spoofing + + +Setting MAC Address, VLAN and Rate Limit Using IProute2 Tool +------------------------------------------------------------ +You can set a MAC address of a Virtual Function (VF), a default VLAN and the +rate limit using the IProute2 tool. Download the latest version of the +IProute2 tool from Sourceforge if your version does not have all the features +you require. + +Credit Based Shaper (Qav Mode) +------------------------------ +When enabling the CBS qdisc in the hardware offload mode, traffic shaping using +the CBS (described in the IEEE 802.1Q-2018 Section 8.6.8.2 and discussed in the +Annex L) algorithm will run in the i210 controller, so it's more accurate and +uses less CPU. + +When using offloaded CBS, and the traffic rate obeys the configured rate +(doesn't go above it), CBS should have little to no effect in the latency. + +The offloaded version of the algorithm has some limits, caused by how the idle +slope is expressed in the adapter's registers. It can only represent idle slopes +in 16.38431 kbps units, which means that if a idle slope of 2576kbps is +requested, the controller will be configured to use a idle slope of ~2589 kbps, +because the driver rounds the value up. For more details, see the comments on +:c:func:`igb_config_tx_modes()`. + +NOTE: This feature is exclusive to i210 models. + + +Support +======= +For general information, go to the Intel support website at: +https://www.intel.com/support/ + +If an issue is identified with the released source code on a supported kernel +with a supported adapter, email the specific information related to the issue +to intel-wired-lan@lists.osuosl.org. diff --git a/Documentation/networking/device_drivers/ethernet/intel/igbvf.rst b/Documentation/networking/device_drivers/ethernet/intel/igbvf.rst new file mode 100644 index 0000000000..11a9017f30 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/intel/igbvf.rst @@ -0,0 +1,60 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +=========================================================== +Linux Base Virtual Function Driver for Intel(R) 1G Ethernet +=========================================================== + +Intel Gigabit Virtual Function Linux driver. +Copyright(c) 1999-2018 Intel Corporation. + +Contents +======== +- Identifying Your Adapter +- Additional Configurations +- Support + +This driver supports Intel 82576-based virtual function devices-based virtual +function devices that can only be activated on kernels that support SR-IOV. + +SR-IOV requires the correct platform and OS support. + +The guest OS loading this driver must support MSI-X interrupts. + +For questions related to hardware requirements, refer to the documentation +supplied with your Intel adapter. All hardware requirements listed apply to use +with Linux. + +Driver information can be obtained using ethtool, lspci, and ifconfig. +Instructions on updating ethtool can be found in the section Additional +Configurations later in this document. + +NOTE: There is a limit of a total of 32 shared VLANs to 1 or more VFs. + + +Identifying Your Adapter +======================== +For information on how to identify your adapter, and for the latest Intel +network drivers, refer to the Intel Support website: +https://www.intel.com/support + + +Additional Features and Configurations +====================================== + +ethtool +------- +The driver utilizes the ethtool interface for driver configuration and +diagnostics, as well as displaying statistical information. The latest ethtool +version is required for this functionality. Download it at: + +https://www.kernel.org/pub/software/network/ethtool/ + + +Support +======= +For general information, go to the Intel support website at: +https://www.intel.com/support/ + +If an issue is identified with the released source code on a supported kernel +with a supported adapter, email the specific information related to the issue +to intel-wired-lan@lists.osuosl.org. diff --git a/Documentation/networking/device_drivers/ethernet/intel/ixgbe.rst b/Documentation/networking/device_drivers/ethernet/intel/ixgbe.rst new file mode 100644 index 0000000000..1e5f16993f --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/intel/ixgbe.rst @@ -0,0 +1,552 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +=========================================================================== +Linux Base Driver for the Intel(R) Ethernet 10 Gigabit PCI Express Adapters +=========================================================================== + +Intel 10 Gigabit Linux driver. +Copyright(c) 1999-2018 Intel Corporation. + +Contents +======== + +- Identifying Your Adapter +- Command Line Parameters +- Additional Configurations +- Known Issues +- Support + +Identifying Your Adapter +======================== +The driver is compatible with devices based on the following: + + * Intel(R) Ethernet Controller 82598 + * Intel(R) Ethernet Controller 82599 + * Intel(R) Ethernet Controller X520 + * Intel(R) Ethernet Controller X540 + * Intel(R) Ethernet Controller x550 + * Intel(R) Ethernet Controller X552 + * Intel(R) Ethernet Controller X553 + +For information on how to identify your adapter, and for the latest Intel +network drivers, refer to the Intel Support website: +https://www.intel.com/support + +SFP+ Devices with Pluggable Optics +---------------------------------- + +82599-BASED ADAPTERS +~~~~~~~~~~~~~~~~~~~~ +NOTES: +- If your 82599-based Intel(R) Network Adapter came with Intel optics or is an +Intel(R) Ethernet Server Adapter X520-2, then it only supports Intel optics +and/or the direct attach cables listed below. +- When 82599-based SFP+ devices are connected back to back, they should be set +to the same Speed setting via ethtool. Results may vary if you mix speed +settings. + ++---------------+---------------------------------------+------------------+ +| Supplier | Type | Part Numbers | ++===============+=======================================+==================+ +| SR Modules | ++---------------+---------------------------------------+------------------+ +| Intel | DUAL RATE 1G/10G SFP+ SR (bailed) | FTLX8571D3BCV-IT | ++---------------+---------------------------------------+------------------+ +| Intel | DUAL RATE 1G/10G SFP+ SR (bailed) | AFBR-703SDZ-IN2 | ++---------------+---------------------------------------+------------------+ +| Intel | DUAL RATE 1G/10G SFP+ SR (bailed) | AFBR-703SDDZ-IN1 | ++---------------+---------------------------------------+------------------+ +| LR Modules | ++---------------+---------------------------------------+------------------+ +| Intel | DUAL RATE 1G/10G SFP+ LR (bailed) | FTLX1471D3BCV-IT | ++---------------+---------------------------------------+------------------+ +| Intel | DUAL RATE 1G/10G SFP+ LR (bailed) | AFCT-701SDZ-IN2 | ++---------------+---------------------------------------+------------------+ +| Intel | DUAL RATE 1G/10G SFP+ LR (bailed) | AFCT-701SDDZ-IN1 | ++---------------+---------------------------------------+------------------+ + +The following is a list of 3rd party SFP+ modules that have received some +testing. Not all modules are applicable to all devices. + ++---------------+---------------------------------------+------------------+ +| Supplier | Type | Part Numbers | ++===============+=======================================+==================+ +| Finisar | SFP+ SR bailed, 10g single rate | FTLX8571D3BCL | ++---------------+---------------------------------------+------------------+ +| Avago | SFP+ SR bailed, 10g single rate | AFBR-700SDZ | ++---------------+---------------------------------------+------------------+ +| Finisar | SFP+ LR bailed, 10g single rate | FTLX1471D3BCL | ++---------------+---------------------------------------+------------------+ +| Finisar | DUAL RATE 1G/10G SFP+ SR (No Bail) | FTLX8571D3QCV-IT | ++---------------+---------------------------------------+------------------+ +| Avago | DUAL RATE 1G/10G SFP+ SR (No Bail) | AFBR-703SDZ-IN1 | ++---------------+---------------------------------------+------------------+ +| Finisar | DUAL RATE 1G/10G SFP+ LR (No Bail) | FTLX1471D3QCV-IT | ++---------------+---------------------------------------+------------------+ +| Avago | DUAL RATE 1G/10G SFP+ LR (No Bail) | AFCT-701SDZ-IN1 | ++---------------+---------------------------------------+------------------+ +| Finisar | 1000BASE-T SFP | FCLF8522P2BTL | ++---------------+---------------------------------------+------------------+ +| Avago | 1000BASE-T | ABCU-5710RZ | ++---------------+---------------------------------------+------------------+ +| HP | 1000BASE-SX SFP | 453153-001 | ++---------------+---------------------------------------+------------------+ + +82599-based adapters support all passive and active limiting direct attach +cables that comply with SFF-8431 v4.1 and SFF-8472 v10.4 specifications. + +Laser turns off for SFP+ when ifconfig ethX down +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +"ifconfig ethX down" turns off the laser for 82599-based SFP+ fiber adapters. +"ifconfig ethX up" turns on the laser. +Alternatively, you can use "ip link set [down/up] dev ethX" to turn the +laser off and on. + + +82599-based QSFP+ Adapters +~~~~~~~~~~~~~~~~~~~~~~~~~~ +NOTES: +- If your 82599-based Intel(R) Network Adapter came with Intel optics, it only +supports Intel optics. +- 82599-based QSFP+ adapters only support 4x10 Gbps connections. 1x40 Gbps +connections are not supported. QSFP+ link partners must be configured for +4x10 Gbps. +- 82599-based QSFP+ adapters do not support automatic link speed detection. +The link speed must be configured to either 10 Gbps or 1 Gbps to match the link +partners speed capabilities. Incorrect speed configurations will result in +failure to link. +- Intel(R) Ethernet Converged Network Adapter X520-Q1 only supports the optics +and direct attach cables listed below. + ++---------------+---------------------------------------+------------------+ +| Supplier | Type | Part Numbers | ++===============+=======================================+==================+ +| Intel | DUAL RATE 1G/10G QSFP+ SRL (bailed) | E10GQSFPSR | ++---------------+---------------------------------------+------------------+ + +82599-based QSFP+ adapters support all passive and active limiting QSFP+ +direct attach cables that comply with SFF-8436 v4.1 specifications. + +82598-BASED ADAPTERS +~~~~~~~~~~~~~~~~~~~~ +NOTES: +- Intel(r) Ethernet Network Adapters that support removable optical modules +only support their original module type (for example, the Intel(R) 10 Gigabit +SR Dual Port Express Module only supports SR optical modules). If you plug in +a different type of module, the driver will not load. +- Hot Swapping/hot plugging optical modules is not supported. +- Only single speed, 10 gigabit modules are supported. +- LAN on Motherboard (LOMs) may support DA, SR, or LR modules. Other module +types are not supported. Please see your system documentation for details. + +The following is a list of SFP+ modules and direct attach cables that have +received some testing. Not all modules are applicable to all devices. + ++---------------+---------------------------------------+------------------+ +| Supplier | Type | Part Numbers | ++===============+=======================================+==================+ +| Finisar | SFP+ SR bailed, 10g single rate | FTLX8571D3BCL | ++---------------+---------------------------------------+------------------+ +| Avago | SFP+ SR bailed, 10g single rate | AFBR-700SDZ | ++---------------+---------------------------------------+------------------+ +| Finisar | SFP+ LR bailed, 10g single rate | FTLX1471D3BCL | ++---------------+---------------------------------------+------------------+ + +82598-based adapters support all passive direct attach cables that comply with +SFF-8431 v4.1 and SFF-8472 v10.4 specifications. Active direct attach cables +are not supported. + +Third party optic modules and cables referred to above are listed only for the +purpose of highlighting third party specifications and potential +compatibility, and are not recommendations or endorsements or sponsorship of +any third party's product by Intel. Intel is not endorsing or promoting +products made by any third party and the third party reference is provided +only to share information regarding certain optic modules and cables with the +above specifications. There may be other manufacturers or suppliers, producing +or supplying optic modules and cables with similar or matching descriptions. +Customers must use their own discretion and diligence to purchase optic +modules and cables from any third party of their choice. Customers are solely +responsible for assessing the suitability of the product and/or devices and +for the selection of the vendor for purchasing any product. THE OPTIC MODULES +AND CABLES REFERRED TO ABOVE ARE NOT WARRANTED OR SUPPORTED BY INTEL. INTEL +ASSUMES NO LIABILITY WHATSOEVER, AND INTEL DISCLAIMS ANY EXPRESS OR IMPLIED +WARRANTY, RELATING TO SALE AND/OR USE OF SUCH THIRD PARTY PRODUCTS OR +SELECTION OF VENDOR BY CUSTOMERS. + +Command Line Parameters +======================= + +max_vfs +------- +:Valid Range: 1-63 + +This parameter adds support for SR-IOV. It causes the driver to spawn up to +max_vfs worth of virtual functions. +If the value is greater than 0 it will also force the VMDq parameter to be 1 or +more. + +NOTE: This parameter is only used on kernel 3.7.x and below. On kernel 3.8.x +and above, use sysfs to enable VFs. Also, for Red Hat distributions, this +parameter is only used on version 6.6 and older. For version 6.7 and newer, use +sysfs. For example:: + + #echo $num_vf_enabled > /sys/class/net/$dev/device/sriov_numvfs // enable VFs + #echo 0 > /sys/class/net/$dev/device/sriov_numvfs //disable VFs + +The parameters for the driver are referenced by position. Thus, if you have a +dual port adapter, or more than one adapter in your system, and want N virtual +functions per port, you must specify a number for each port with each parameter +separated by a comma. For example:: + + modprobe ixgbe max_vfs=4 + +This will spawn 4 VFs on the first port. + +:: + + modprobe ixgbe max_vfs=2,4 + +This will spawn 2 VFs on the first port and 4 VFs on the second port. + +NOTE: Caution must be used in loading the driver with these parameters. +Depending on your system configuration, number of slots, etc., it is impossible +to predict in all cases where the positions would be on the command line. + +NOTE: Neither the device nor the driver control how VFs are mapped into config +space. Bus layout will vary by operating system. On operating systems that +support it, you can check sysfs to find the mapping. + +NOTE: When either SR-IOV mode or VMDq mode is enabled, hardware VLAN filtering +and VLAN tag stripping/insertion will remain enabled. Please remove the old +VLAN filter before the new VLAN filter is added. For example, + +:: + + ip link set eth0 vf 0 vlan 100 // set VLAN 100 for VF 0 + ip link set eth0 vf 0 vlan 0 // Delete VLAN 100 + ip link set eth0 vf 0 vlan 200 // set a new VLAN 200 for VF 0 + +With kernel 3.6, the driver supports the simultaneous usage of max_vfs and DCB +features, subject to the constraints described below. Prior to kernel 3.6, the +driver did not support the simultaneous operation of max_vfs greater than 0 and +the DCB features (multiple traffic classes utilizing Priority Flow Control and +Extended Transmission Selection). + +When DCB is enabled, network traffic is transmitted and received through +multiple traffic classes (packet buffers in the NIC). The traffic is associated +with a specific class based on priority, which has a value of 0 through 7 used +in the VLAN tag. When SR-IOV is not enabled, each traffic class is associated +with a set of receive/transmit descriptor queue pairs. The number of queue +pairs for a given traffic class depends on the hardware configuration. When +SR-IOV is enabled, the descriptor queue pairs are grouped into pools. The +Physical Function (PF) and each Virtual Function (VF) is allocated a pool of +receive/transmit descriptor queue pairs. When multiple traffic classes are +configured (for example, DCB is enabled), each pool contains a queue pair from +each traffic class. When a single traffic class is configured in the hardware, +the pools contain multiple queue pairs from the single traffic class. + +The number of VFs that can be allocated depends on the number of traffic +classes that can be enabled. The configurable number of traffic classes for +each enabled VF is as follows: +0 - 15 VFs = Up to 8 traffic classes, depending on device support +16 - 31 VFs = Up to 4 traffic classes +32 - 63 VFs = 1 traffic class + +When VFs are configured, the PF is allocated one pool as well. The PF supports +the DCB features with the constraint that each traffic class will only use a +single queue pair. When zero VFs are configured, the PF can support multiple +queue pairs per traffic class. + +allow_unsupported_sfp +--------------------- +:Valid Range: 0,1 +:Default Value: 0 (disabled) + +This parameter allows unsupported and untested SFP+ modules on 82599-based +adapters, as long as the type of module is known to the driver. + +debug +----- +:Valid Range: 0-16 (0=none,...,16=all) +:Default Value: 0 + +This parameter adjusts the level of debug messages displayed in the system +logs. + + +Additional Features and Configurations +====================================== + +Flow Control +------------ +Ethernet Flow Control (IEEE 802.3x) can be configured with ethtool to enable +receiving and transmitting pause frames for ixgbe. When transmit is enabled, +pause frames are generated when the receive packet buffer crosses a predefined +threshold. When receive is enabled, the transmit unit will halt for the time +delay specified when a pause frame is received. + +NOTE: You must have a flow control capable link partner. + +Flow Control is enabled by default. + +Use ethtool to change the flow control settings. To enable or disable Rx or +Tx Flow Control:: + + ethtool -A eth? rx <on|off> tx <on|off> + +Note: This command only enables or disables Flow Control if auto-negotiation is +disabled. If auto-negotiation is enabled, this command changes the parameters +used for auto-negotiation with the link partner. + +To enable or disable auto-negotiation:: + + ethtool -s eth? autoneg <on|off> + +Note: Flow Control auto-negotiation is part of link auto-negotiation. Depending +on your device, you may not be able to change the auto-negotiation setting. + +NOTE: For 82598 backplane cards entering 1 gigabit mode, flow control default +behavior is changed to off. Flow control in 1 gigabit mode on these devices can +lead to transmit hangs. + +Intel(R) Ethernet Flow Director +------------------------------- +The Intel Ethernet Flow Director performs the following tasks: + +- Directs receive packets according to their flows to different queues. +- Enables tight control on routing a flow in the platform. +- Matches flows and CPU cores for flow affinity. +- Supports multiple parameters for flexible flow classification and load + balancing (in SFP mode only). + +NOTE: Intel Ethernet Flow Director masking works in the opposite manner from +subnet masking. In the following command:: + + #ethtool -N eth11 flow-type ip4 src-ip 172.4.1.2 m 255.0.0.0 dst-ip \ + 172.21.1.1 m 255.128.0.0 action 31 + +The src-ip value that is written to the filter will be 0.4.1.2, not 172.0.0.0 +as might be expected. Similarly, the dst-ip value written to the filter will be +0.21.1.1, not 172.0.0.0. + +To enable or disable the Intel Ethernet Flow Director:: + + # ethtool -K ethX ntuple <on|off> + +When disabling ntuple filters, all the user programmed filters are flushed from +the driver cache and hardware. All needed filters must be re-added when ntuple +is re-enabled. + +To add a filter that directs packet to queue 2, use -U or -N switch:: + + # ethtool -N ethX flow-type tcp4 src-ip 192.168.10.1 dst-ip \ + 192.168.10.2 src-port 2000 dst-port 2001 action 2 [loc 1] + +To see the list of filters currently present:: + + # ethtool <-u|-n> ethX + +Sideband Perfect Filters +------------------------ +Sideband Perfect Filters are used to direct traffic that matches specified +characteristics. They are enabled through ethtool's ntuple interface. To add a +new filter use the following command:: + + ethtool -U <device> flow-type <type> src-ip <ip> dst-ip <ip> src-port <port> \ + dst-port <port> action <queue> + +Where: + <device> - the ethernet device to program + <type> - can be ip4, tcp4, udp4, or sctp4 + <ip> - the IP address to match on + <port> - the port number to match on + <queue> - the queue to direct traffic towards (-1 discards the matched traffic) + +Use the following command to delete a filter:: + + ethtool -U <device> delete <N> + +Where <N> is the filter id displayed when printing all the active filters, and +may also have been specified using "loc <N>" when adding the filter. + +The following example matches TCP traffic sent from 192.168.0.1, port 5300, +directed to 192.168.0.5, port 80, and sends it to queue 7:: + + ethtool -U enp130s0 flow-type tcp4 src-ip 192.168.0.1 dst-ip 192.168.0.5 \ + src-port 5300 dst-port 80 action 7 + +For each flow-type, the programmed filters must all have the same matching +input set. For example, issuing the following two commands is acceptable:: + + ethtool -U enp130s0 flow-type ip4 src-ip 192.168.0.1 src-port 5300 action 7 + ethtool -U enp130s0 flow-type ip4 src-ip 192.168.0.5 src-port 55 action 10 + +Issuing the next two commands, however, is not acceptable, since the first +specifies src-ip and the second specifies dst-ip:: + + ethtool -U enp130s0 flow-type ip4 src-ip 192.168.0.1 src-port 5300 action 7 + ethtool -U enp130s0 flow-type ip4 dst-ip 192.168.0.5 src-port 55 action 10 + +The second command will fail with an error. You may program multiple filters +with the same fields, using different values, but, on one device, you may not +program two TCP4 filters with different matching fields. + +Matching on a sub-portion of a field is not supported by the ixgbe driver, thus +partial mask fields are not supported. + +To create filters that direct traffic to a specific Virtual Function, use the +"user-def" parameter. Specify the user-def as a 64 bit value, where the lower 32 +bits represents the queue number, while the next 8 bits represent which VF. +Note that 0 is the PF, so the VF identifier is offset by 1. For example:: + + ... user-def 0x800000002 ... + +specifies to direct traffic to Virtual Function 7 (8 minus 1) into queue 2 of +that VF. + +Note that these filters will not break internal routing rules, and will not +route traffic that otherwise would not have been sent to the specified Virtual +Function. + +Jumbo Frames +------------ +Jumbo Frames support is enabled by changing the Maximum Transmission Unit (MTU) +to a value larger than the default value of 1500. + +Use the ifconfig command to increase the MTU size. For example, enter the +following where <x> is the interface number:: + + ifconfig eth<x> mtu 9000 up + +Alternatively, you can use the ip command as follows:: + + ip link set mtu 9000 dev eth<x> + ip link set up dev eth<x> + +This setting is not saved across reboots. The setting change can be made +permanent by adding 'MTU=9000' to the file:: + + /etc/sysconfig/network-scripts/ifcfg-eth<x> // for RHEL + /etc/sysconfig/network/<config_file> // for SLES + +NOTE: The maximum MTU setting for Jumbo Frames is 9710. This value coincides +with the maximum Jumbo Frames size of 9728 bytes. + +NOTE: This driver will attempt to use multiple page sized buffers to receive +each jumbo packet. This should help to avoid buffer starvation issues when +allocating receive packets. + +NOTE: For 82599-based network connections, if you are enabling jumbo frames in +a virtual function (VF), jumbo frames must first be enabled in the physical +function (PF). The VF MTU setting cannot be larger than the PF MTU. + +NBASE-T Support +--------------- +The ixgbe driver supports NBASE-T on some devices. However, the advertisement +of NBASE-T speeds is suppressed by default, to accommodate broken network +switches which cannot cope with advertised NBASE-T speeds. Use the ethtool +command to enable advertising NBASE-T speeds on devices which support it:: + + ethtool -s eth? advertise 0x1800000001028 + +On Linux systems with INTERFACES(5), this can be specified as a pre-up command +in /etc/network/interfaces so that the interface is always brought up with +NBASE-T support, e.g.:: + + iface eth? inet dhcp + pre-up ethtool -s eth? advertise 0x1800000001028 || true + +Generic Receive Offload, aka GRO +-------------------------------- +The driver supports the in-kernel software implementation of GRO. GRO has +shown that by coalescing Rx traffic into larger chunks of data, CPU +utilization can be significantly reduced when under large Rx load. GRO is an +evolution of the previously-used LRO interface. GRO is able to coalesce +other protocols besides TCP. It's also safe to use with configurations that +are problematic for LRO, namely bridging and iSCSI. + +Data Center Bridging (DCB) +-------------------------- +NOTE: +The kernel assumes that TC0 is available, and will disable Priority Flow +Control (PFC) on the device if TC0 is not available. To fix this, ensure TC0 is +enabled when setting up DCB on your switch. + +DCB is a configuration Quality of Service implementation in hardware. It uses +the VLAN priority tag (802.1p) to filter traffic. That means that there are 8 +different priorities that traffic can be filtered into. It also enables +priority flow control (802.1Qbb) which can limit or eliminate the number of +dropped packets during network stress. Bandwidth can be allocated to each of +these priorities, which is enforced at the hardware level (802.1Qaz). + +Adapter firmware implements LLDP and DCBX protocol agents as per 802.1AB and +802.1Qaz respectively. The firmware based DCBX agent runs in willing mode only +and can accept settings from a DCBX capable peer. Software configuration of +DCBX parameters via dcbtool/lldptool are not supported. + +The ixgbe driver implements the DCB netlink interface layer to allow user-space +to communicate with the driver and query DCB configuration for the port. + +ethtool +------- +The driver utilizes the ethtool interface for driver configuration and +diagnostics, as well as displaying statistical information. The latest ethtool +version is required for this functionality. Download it at: +https://www.kernel.org/pub/software/network/ethtool/ + +FCoE +---- +The ixgbe driver supports Fiber Channel over Ethernet (FCoE) and Data Center +Bridging (DCB). This code has no default effect on the regular driver +operation. Configuring DCB and FCoE is outside the scope of this README. Refer +to http://www.open-fcoe.org/ for FCoE project information and contact +ixgbe-eedc@lists.sourceforge.net for DCB information. + +MAC and VLAN anti-spoofing feature +---------------------------------- +When a malicious driver attempts to send a spoofed packet, it is dropped by the +hardware and not transmitted. + +An interrupt is sent to the PF driver notifying it of the spoof attempt. When a +spoofed packet is detected, the PF driver will send the following message to +the system log (displayed by the "dmesg" command):: + + ixgbe ethX: ixgbe_spoof_check: n spoofed packets detected + +where "x" is the PF interface number; and "n" is number of spoofed packets. +NOTE: This feature can be disabled for a specific Virtual Function (VF):: + + ip link set <pf dev> vf <vf id> spoofchk {off|on} + +IPsec Offload +------------- +The ixgbe driver supports IPsec Hardware Offload. When creating Security +Associations with "ip xfrm ..." the 'offload' tag option can be used to +register the IPsec SA with the driver in order to get higher throughput in +the secure communications. + +The offload is also supported for ixgbe's VFs, but the VF must be set as +'trusted' and the support must be enabled with:: + + ethtool --set-priv-flags eth<x> vf-ipsec on + ip link set eth<x> vf <y> trust on + + +Known Issues/Troubleshooting +============================ + +Enabling SR-IOV in a 64-bit Microsoft Windows Server 2012/R2 guest OS +--------------------------------------------------------------------- +Linux KVM Hypervisor/VMM supports direct assignment of a PCIe device to a VM. +This includes traditional PCIe devices, as well as SR-IOV-capable devices based +on the Intel Ethernet Controller XL710. + + +Support +======= +For general information, go to the Intel support website at: +https://www.intel.com/support/ + +If an issue is identified with the released source code on a supported kernel +with a supported adapter, email the specific information related to the issue +to intel-wired-lan@lists.osuosl.org. diff --git a/Documentation/networking/device_drivers/ethernet/intel/ixgbevf.rst b/Documentation/networking/device_drivers/ethernet/intel/ixgbevf.rst new file mode 100644 index 0000000000..08dc0d368a --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/intel/ixgbevf.rst @@ -0,0 +1,62 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +============================================================ +Linux Base Virtual Function Driver for Intel(R) 10G Ethernet +============================================================ + +Intel 10 Gigabit Virtual Function Linux driver. +Copyright(c) 1999-2018 Intel Corporation. + +Contents +======== + +- Identifying Your Adapter +- Known Issues +- Support + +This driver supports 82599, X540, X550, and X552-based virtual function devices +that can only be activated on kernels that support SR-IOV. + +For questions related to hardware requirements, refer to the documentation +supplied with your Intel adapter. All hardware requirements listed apply to use +with Linux. + + +Identifying Your Adapter +======================== +The driver is compatible with devices based on the following: + + * Intel(R) Ethernet Controller 82598 + * Intel(R) Ethernet Controller 82599 + * Intel(R) Ethernet Controller X520 + * Intel(R) Ethernet Controller X540 + * Intel(R) Ethernet Controller x550 + * Intel(R) Ethernet Controller X552 + * Intel(R) Ethernet Controller X553 + +For information on how to identify your adapter, and for the latest Intel +network drivers, refer to the Intel Support website: +https://www.intel.com/support + +Known Issues/Troubleshooting +============================ + +SR-IOV requires the correct platform and OS support. + +The guest OS loading this driver must support MSI-X interrupts. + +This driver is only supported as a loadable module at this time. Intel is not +supplying patches against the kernel source to allow for static linking of the +drivers. + +VLANs: There is a limit of a total of 64 shared VLANs to 1 or more VFs. + + +Support +======= +For general information, go to the Intel support website at: +https://www.intel.com/support/ + +If an issue is identified with the released source code on a supported kernel +with a supported adapter, email the specific information related to the issue +to intel-wired-lan@lists.osuosl.org. diff --git a/Documentation/networking/device_drivers/ethernet/marvell/octeon_ep.rst b/Documentation/networking/device_drivers/ethernet/marvell/octeon_ep.rst new file mode 100644 index 0000000000..cad96c8d1f --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/marvell/octeon_ep.rst @@ -0,0 +1,36 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +==================================================================== +Linux kernel networking driver for Marvell's Octeon PCI Endpoint NIC +==================================================================== + +Network driver for Marvell's Octeon PCI EndPoint NIC. +Copyright (c) 2020 Marvell International Ltd. + +Contents +======== + +- `Overview`_ +- `Supported Devices`_ +- `Interface Control`_ + +Overview +======== +This driver implements networking functionality of Marvell's Octeon PCI +EndPoint NIC. + +Supported Devices +================= +Currently, this driver support following devices: + * Network controller: Cavium, Inc. Device b200 + * Network controller: Cavium, Inc. Device b400 + +Interface Control +================= +Network Interface control like changing mtu, link speed, link down/up are +done by writing command to mailbox command queue, a mailbox interface +implemented through a reserved region in BAR4. +This driver writes the commands into the mailbox and the firmware on the +Octeon device processes them. The firmware also sends unsolicited notifications +to driver for events suchs as link change, through notification queue +implemented as part of mailbox interface. diff --git a/Documentation/networking/device_drivers/ethernet/marvell/octeontx2.rst b/Documentation/networking/device_drivers/ethernet/marvell/octeontx2.rst new file mode 100644 index 0000000000..1e196cb9ce --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/marvell/octeontx2.rst @@ -0,0 +1,342 @@ +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) + +==================================== +Marvell OcteonTx2 RVU Kernel Drivers +==================================== + +Copyright (c) 2020 Marvell International Ltd. + +Contents +======== + +- `Overview`_ +- `Drivers`_ +- `Basic packet flow`_ +- `Devlink health reporters`_ +- `Quality of service`_ + +Overview +======== + +Resource virtualization unit (RVU) on Marvell's OcteonTX2 SOC maps HW +resources from the network, crypto and other functional blocks into +PCI-compatible physical and virtual functions. Each functional block +again has multiple local functions (LFs) for provisioning to PCI devices. +RVU supports multiple PCIe SRIOV physical functions (PFs) and virtual +functions (VFs). PF0 is called the administrative / admin function (AF) +and has privileges to provision RVU functional block's LFs to each of the +PF/VF. + +RVU managed networking functional blocks + - Network pool or buffer allocator (NPA) + - Network interface controller (NIX) + - Network parser CAM (NPC) + - Schedule/Synchronize/Order unit (SSO) + - Loopback interface (LBK) + +RVU managed non-networking functional blocks + - Crypto accelerator (CPT) + - Scheduled timers unit (TIM) + - Schedule/Synchronize/Order unit (SSO) + Used for both networking and non networking usecases + +Resource provisioning examples + - A PF/VF with NIX-LF & NPA-LF resources works as a pure network device + - A PF/VF with CPT-LF resource works as a pure crypto offload device. + +RVU functional blocks are highly configurable as per software requirements. + +Firmware setups following stuff before kernel boots + - Enables required number of RVU PFs based on number of physical links. + - Number of VFs per PF are either static or configurable at compile time. + Based on config, firmware assigns VFs to each of the PFs. + - Also assigns MSIX vectors to each of PF and VFs. + - These are not changed after kernel boot. + +Drivers +======= + +Linux kernel will have multiple drivers registering to different PF and VFs +of RVU. Wrt networking there will be 3 flavours of drivers. + +Admin Function driver +--------------------- + +As mentioned above RVU PF0 is called the admin function (AF), this driver +supports resource provisioning and configuration of functional blocks. +Doesn't handle any I/O. It sets up few basic stuff but most of the +funcionality is achieved via configuration requests from PFs and VFs. + +PF/VFs communicates with AF via a shared memory region (mailbox). Upon +receiving requests AF does resource provisioning and other HW configuration. +AF is always attached to host kernel, but PFs and their VFs may be used by host +kernel itself, or attached to VMs or to userspace applications like +DPDK etc. So AF has to handle provisioning/configuration requests sent +by any device from any domain. + +AF driver also interacts with underlying firmware to + - Manage physical ethernet links ie CGX LMACs. + - Retrieve information like speed, duplex, autoneg etc + - Retrieve PHY EEPROM and stats. + - Configure FEC, PAM modes + - etc + +From pure networking side AF driver supports following functionality. + - Map a physical link to a RVU PF to which a netdev is registered. + - Attach NIX and NPA block LFs to RVU PF/VF which provide buffer pools, RQs, SQs + for regular networking functionality. + - Flow control (pause frames) enable/disable/config. + - HW PTP timestamping related config. + - NPC parser profile config, basically how to parse pkt and what info to extract. + - NPC extract profile config, what to extract from the pkt to match data in MCAM entries. + - Manage NPC MCAM entries, upon request can frame and install requested packet forwarding rules. + - Defines receive side scaling (RSS) algorithms. + - Defines segmentation offload algorithms (eg TSO) + - VLAN stripping, capture and insertion config. + - SSO and TIM blocks config which provide packet scheduling support. + - Debugfs support, to check current resource provising, current status of + NPA pools, NIX RQ, SQ and CQs, various stats etc which helps in debugging issues. + - And many more. + +Physical Function driver +------------------------ + +This RVU PF handles IO, is mapped to a physical ethernet link and this +driver registers a netdev. This supports SR-IOV. As said above this driver +communicates with AF with a mailbox. To retrieve information from physical +links this driver talks to AF and AF gets that info from firmware and responds +back ie cannot talk to firmware directly. + +Supports ethtool for configuring links, RSS, queue count, queue size, +flow control, ntuple filters, dump PHY EEPROM, config FEC etc. + +Virtual Function driver +----------------------- + +There are two types VFs, VFs that share the physical link with their parent +SR-IOV PF and the VFs which work in pairs using internal HW loopback channels (LBK). + +Type1: + - These VFs and their parent PF share a physical link and used for outside communication. + - VFs cannot communicate with AF directly, they send mbox message to PF and PF + forwards that to AF. AF after processing, responds back to PF and PF forwards + the reply to VF. + - From functionality point of view there is no difference between PF and VF as same type + HW resources are attached to both. But user would be able to configure few stuff only + from PF as PF is treated as owner/admin of the link. + +Type2: + - RVU PF0 ie admin function creates these VFs and maps them to loopback block's channels. + - A set of two VFs (VF0 & VF1, VF2 & VF3 .. so on) works as a pair ie pkts sent out of + VF0 will be received by VF1 and vice versa. + - These VFs can be used by applications or virtual machines to communicate between them + without sending traffic outside. There is no switch present in HW, hence the support + for loopback VFs. + - These communicate directly with AF (PF0) via mbox. + +Except for the IO channels or links used for packet reception and transmission there is +no other difference between these VF types. AF driver takes care of IO channel mapping, +hence same VF driver works for both types of devices. + +Basic packet flow +================= + +Ingress +------- + +1. CGX LMAC receives packet. +2. Forwards the packet to the NIX block. +3. Then submitted to NPC block for parsing and then MCAM lookup to get the destination RVU device. +4. NIX LF attached to the destination RVU device allocates a buffer from RQ mapped buffer pool of NPA block LF. +5. RQ may be selected by RSS or by configuring MCAM rule with a RQ number. +6. Packet is DMA'ed and driver is notified. + +Egress +------ + +1. Driver prepares a send descriptor and submits to SQ for transmission. +2. The SQ is already configured (by AF) to transmit on a specific link/channel. +3. The SQ descriptor ring is maintained in buffers allocated from SQ mapped pool of NPA block LF. +4. NIX block transmits the pkt on the designated channel. +5. NPC MCAM entries can be installed to divert pkt onto a different channel. + +Devlink health reporters +======================== + +NPA Reporters +------------- +The NPA reporters are responsible for reporting and recovering the following group of errors: + +1. GENERAL events + + - Error due to operation of unmapped PF. + - Error due to disabled alloc/free for other HW blocks (NIX, SSO, TIM, DPI and AURA). + +2. ERROR events + + - Fault due to NPA_AQ_INST_S read or NPA_AQ_RES_S write. + - AQ Doorbell Error. + +3. RAS events + + - RAS Error Reporting for NPA_AQ_INST_S/NPA_AQ_RES_S. + +4. RVU events + + - Error due to unmapped slot. + +Sample Output:: + + ~# devlink health + pci/0002:01:00.0: + reporter hw_npa_intr + state healthy error 2872 recover 2872 last_dump_date 2020-12-10 last_dump_time 09:39:09 grace_period 0 auto_recover true auto_dump true + reporter hw_npa_gen + state healthy error 2872 recover 2872 last_dump_date 2020-12-11 last_dump_time 04:43:04 grace_period 0 auto_recover true auto_dump true + reporter hw_npa_err + state healthy error 2871 recover 2871 last_dump_date 2020-12-10 last_dump_time 09:39:17 grace_period 0 auto_recover true auto_dump true + reporter hw_npa_ras + state healthy error 0 recover 0 last_dump_date 2020-12-10 last_dump_time 09:32:40 grace_period 0 auto_recover true auto_dump true + +Each reporter dumps the + + - Error Type + - Error Register value + - Reason in words + +For example:: + + ~# devlink health dump show pci/0002:01:00.0 reporter hw_npa_gen + NPA_AF_GENERAL: + NPA General Interrupt Reg : 1 + NIX0: free disabled RX + ~# devlink health dump show pci/0002:01:00.0 reporter hw_npa_intr + NPA_AF_RVU: + NPA RVU Interrupt Reg : 1 + Unmap Slot Error + ~# devlink health dump show pci/0002:01:00.0 reporter hw_npa_err + NPA_AF_ERR: + NPA Error Interrupt Reg : 4096 + AQ Doorbell Error + + +NIX Reporters +------------- +The NIX reporters are responsible for reporting and recovering the following group of errors: + +1. GENERAL events + + - Receive mirror/multicast packet drop due to insufficient buffer. + - SMQ Flush operation. + +2. ERROR events + + - Memory Fault due to WQE read/write from multicast/mirror buffer. + - Receive multicast/mirror replication list error. + - Receive packet on an unmapped PF. + - Fault due to NIX_AQ_INST_S read or NIX_AQ_RES_S write. + - AQ Doorbell Error. + +3. RAS events + + - RAS Error Reporting for NIX Receive Multicast/Mirror Entry Structure. + - RAS Error Reporting for WQE/Packet Data read from Multicast/Mirror Buffer.. + - RAS Error Reporting for NIX_AQ_INST_S/NIX_AQ_RES_S. + +4. RVU events + + - Error due to unmapped slot. + +Sample Output:: + + ~# ./devlink health + pci/0002:01:00.0: + reporter hw_npa_intr + state healthy error 0 recover 0 grace_period 0 auto_recover true auto_dump true + reporter hw_npa_gen + state healthy error 0 recover 0 grace_period 0 auto_recover true auto_dump true + reporter hw_npa_err + state healthy error 0 recover 0 grace_period 0 auto_recover true auto_dump true + reporter hw_npa_ras + state healthy error 0 recover 0 grace_period 0 auto_recover true auto_dump true + reporter hw_nix_intr + state healthy error 1121 recover 1121 last_dump_date 2021-01-19 last_dump_time 05:42:26 grace_period 0 auto_recover true auto_dump true + reporter hw_nix_gen + state healthy error 949 recover 949 last_dump_date 2021-01-19 last_dump_time 05:42:43 grace_period 0 auto_recover true auto_dump true + reporter hw_nix_err + state healthy error 1147 recover 1147 last_dump_date 2021-01-19 last_dump_time 05:42:59 grace_period 0 auto_recover true auto_dump true + reporter hw_nix_ras + state healthy error 409 recover 409 last_dump_date 2021-01-19 last_dump_time 05:43:16 grace_period 0 auto_recover true auto_dump true + +Each reporter dumps the + + - Error Type + - Error Register value + - Reason in words + +For example:: + + ~# devlink health dump show pci/0002:01:00.0 reporter hw_nix_intr + NIX_AF_RVU: + NIX RVU Interrupt Reg : 1 + Unmap Slot Error + ~# devlink health dump show pci/0002:01:00.0 reporter hw_nix_gen + NIX_AF_GENERAL: + NIX General Interrupt Reg : 1 + Rx multicast pkt drop + ~# devlink health dump show pci/0002:01:00.0 reporter hw_nix_err + NIX_AF_ERR: + NIX Error Interrupt Reg : 64 + Rx on unmapped PF_FUNC + + +Quality of service +================== + + +Hardware algorithms used in scheduling +-------------------------------------- + +octeontx2 silicon and CN10K transmit interface consists of five transmit levels +starting from SMQ/MDQ, TL4 to TL1. Each packet will traverse MDQ, TL4 to TL1 +levels. Each level contains an array of queues to support scheduling and shaping. +The hardware uses the below algorithms depending on the priority of scheduler queues. +once the usercreates tc classes with different priorities, the driver configures +schedulers allocated to the class with specified priority along with rate-limiting +configuration. + +1. Strict Priority + + - Once packets are submitted to MDQ, hardware picks all active MDQs having different priority + using strict priority. + +2. Round Robin + + - Active MDQs having the same priority level are chosen using round robin. + + +Setup HTB offload +----------------- + +1. Enable HW TC offload on the interface:: + + # ethtool -K <interface> hw-tc-offload on + +2. Crate htb root:: + + # tc qdisc add dev <interface> clsact + # tc qdisc replace dev <interface> root handle 1: htb offload + +3. Create tc classes with different priorities:: + + # tc class add dev <interface> parent 1: classid 1:1 htb rate 10Gbit prio 1 + + # tc class add dev <interface> parent 1: classid 1:2 htb rate 10Gbit prio 7 + +4. Create tc classes with same priorities and different quantum:: + + # tc class add dev <interface> parent 1: classid 1:1 htb rate 10Gbit prio 2 quantum 409600 + + # tc class add dev <interface> parent 1: classid 1:2 htb rate 10Gbit prio 2 quantum 188416 + + # tc class add dev <interface> parent 1: classid 1:3 htb rate 10Gbit prio 2 quantum 32768 diff --git a/Documentation/networking/device_drivers/ethernet/mellanox/mlx5/counters.rst b/Documentation/networking/device_drivers/ethernet/mellanox/mlx5/counters.rst new file mode 100644 index 0000000000..f69ee1ebee --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/mellanox/mlx5/counters.rst @@ -0,0 +1,1305 @@ +.. SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB +.. include:: <isonum.txt> + +================ +Ethtool counters +================ + +:Copyright: |copy| 2023, NVIDIA CORPORATION & AFFILIATES. All rights reserved. + +Contents +======== + +- `Overview`_ +- `Groups`_ +- `Types`_ +- `Descriptions`_ + +Overview +======== + +There are several counter groups based on where the counter is being counted. In +addition, each group of counters may have different counter types. + +These counter groups are based on which component in a networking setup, +illustrated below, that they describe:: + + ---------------------------------------- + | | + ---------------------------------------- ---------------------------------------- | + | Hypervisor | | VM | | + | | | | | + | ------------------- --------------- | | ------------------- --------------- | | + | | Ethernet driver | | RDMA driver | | | | Ethernet driver | | RDMA driver | | | + | ------------------- --------------- | | ------------------- --------------- | | + | | | | | | | | | + | ------------------- | | ------------------- | | + | | | | | |-- + ---------------------------------------- ---------------------------------------- + | | + ------------- ----------------------------- + | | + ------ ------ ------ ------ ------ ------ ------ + -----| PF |----------------------| VF |-| VF |-| VF |----- --| PF |--- --| PF |--- --| PF |--- + | ------ ------ ------ ------ | | ------ | | ------ | | ------ | + | | | | | | | | + | | | | | | | | + | | | | | | | | + | eSwitch | | eSwitch | | eSwitch | | eSwitch | + ---------------------------------------------------------- ----------- ----------- ----------- + ------------------------------------------------------------------------------- + | | + | | + | Uplink (no counters) | + ------------------------------------------------------------------------------- + --------------------------------------------------------------- + | | + | | + | MPFS (no counters) | + --------------------------------------------------------------- + | + | + | Port + +Groups +====== + +Ring + Software counters populated by the driver stack. + +Netdev + An aggregation of software ring counters. + +vPort counters + Traffic counters and drops due to steering or no buffers. May indicate issues + with NIC. These counters include Ethernet traffic counters (including Raw + Ethernet) and RDMA/RoCE traffic counters. + +Physical port counters + Counters that collect statistics about the PFs and VFs. May indicate issues + with NIC, link, or network. This measuring point holds information on + standardized counters like IEEE 802.3, RFC2863, RFC 2819, RFC 3635 and + additional counters like flow control, FEC and more. Physical port counters + are not exposed to virtual machines. + +Priority Port Counters + A set of the physical port counters, per priority per port. + +Types +===== + +Counters are divided into three types. + +Traffic Informative Counters + Counters which count traffic. These counters can be used for load estimation + or for general debug. + +Traffic Acceleration Counters + Counters which count traffic that was accelerated by Mellanox driver or by + hardware. The counters are an additional layer to the informative counter set, + and the same traffic is counted in both informative and acceleration counters. + +.. [#accel] Traffic acceleration counter. + +Error Counters + Increment of these counters might indicate a problem. Each of these counters + has an explanation and correction action. + +Statistic can be fetched via the `ip link` or `ethtool` commands. `ethtool` +provides more detailed information.:: + + ip –s link show <if-name> + ethtool -S <if-name> + +Descriptions +============ + +XSK, PTP, and QoS counters that are similar to counters defined previously will +not be separately listed. For example, `ptp_tx[i]_packets` will not be +explicitly documented since `tx[i]_packets` describes the behavior of both +counters, except `ptp_tx[i]_packets` is only counted when precision time +protocol is used. + +Ring / Netdev Counter +---------------------------- +The following counters are available per ring or software port. + +These counters provide information on the amount of traffic that was accelerated +by the NIC. The counters are counting the accelerated traffic in addition to the +standard counters which counts it (i.e. accelerated traffic is counted twice). + +The counter names in the table below refers to both ring and port counters. The +notation for ring counters includes the [i] index without the braces. The +notation for port counters doesn't include the [i]. A counter name +`rx[i]_packets` will be printed as `rx0_packets` for ring 0 and `rx_packets` for +the software port. + +.. flat-table:: Ring / Software Port Counter Table + :widths: 2 3 1 + + * - Counter + - Description + - Type + + * - `rx[i]_packets` + - The number of packets received on ring i. + - Informative + + * - `rx[i]_bytes` + - The number of bytes received on ring i. + - Informative + + * - `tx[i]_packets` + - The number of packets transmitted on ring i. + - Informative + + * - `tx[i]_bytes` + - The number of bytes transmitted on ring i. + - Informative + + * - `tx[i]_recover` + - The number of times the SQ was recovered. + - Error + + * - `tx[i]_cqes` + - Number of CQEs events on SQ issued on ring i. + - Informative + + * - `tx[i]_cqe_err` + - The number of error CQEs encountered on the SQ for ring i. + - Error + + * - `tx[i]_tso_packets` + - The number of TSO packets transmitted on ring i [#accel]_. + - Acceleration + + * - `tx[i]_tso_bytes` + - The number of TSO bytes transmitted on ring i [#accel]_. + - Acceleration + + * - `tx[i]_tso_inner_packets` + - The number of TSO packets which are indicated to be carry internal + encapsulation transmitted on ring i [#accel]_. + - Acceleration + + * - `tx[i]_tso_inner_bytes` + - The number of TSO bytes which are indicated to be carry internal + encapsulation transmitted on ring i [#accel]_. + - Acceleration + + * - `rx[i]_gro_packets` + - Number of received packets processed using hardware-accelerated GRO. The + number of hardware GRO offloaded packets received on ring i. + - Acceleration + + * - `rx[i]_gro_bytes` + - Number of received bytes processed using hardware-accelerated GRO. The + number of hardware GRO offloaded bytes received on ring i. + - Acceleration + + * - `rx[i]_gro_skbs` + - The number of receive SKBs constructed while performing + hardware-accelerated GRO. + - Informative + + * - `rx[i]_gro_match_packets` + - Number of received packets processed using hardware-accelerated GRO that + met the flow table match criteria. + - Informative + + * - `rx[i]_gro_large_hds` + - Number of receive packets using hardware-accelerated GRO that have large + headers that require additional memory to be allocated. + - Informative + + * - `rx[i]_lro_packets` + - The number of LRO packets received on ring i [#accel]_. + - Acceleration + + * - `rx[i]_lro_bytes` + - The number of LRO bytes received on ring i [#accel]_. + - Acceleration + + * - `rx[i]_ecn_mark` + - The number of received packets where the ECN mark was turned on. + - Informative + + * - `rx_oversize_pkts_buffer` + - The number of dropped received packets due to length which arrived to RQ + and exceed software buffer size allocated by the device for incoming + traffic. It might imply that the device MTU is larger than the software + buffers size. + - Error + + * - `rx_oversize_pkts_sw_drop` + - Number of received packets dropped in software because the CQE data is + larger than the MTU size. + - Error + + * - `rx[i]_csum_unnecessary` + - Packets received with a `CHECKSUM_UNNECESSARY` on ring i [#accel]_. + - Acceleration + + * - `rx[i]_csum_unnecessary_inner` + - Packets received with inner encapsulation with a `CHECKSUM_UNNECESSARY` + on ring i [#accel]_. + - Acceleration + + * - `rx[i]_csum_none` + - Packets received with a `CHECKSUM_NONE` on ring i [#accel]_. + - Acceleration + + * - `rx[i]_csum_complete` + - Packets received with a `CHECKSUM_COMPLETE` on ring i [#accel]_. + - Acceleration + + * - `rx[i]_csum_complete_tail` + - Number of received packets that had checksum calculation computed, + potentially needed padding, and were able to do so with + `CHECKSUM_PARTIAL`. + - Informative + + * - `rx[i]_csum_complete_tail_slow` + - Number of received packets that need padding larger than eight bytes for + the checksum. + - Informative + + * - `tx[i]_csum_partial` + - Packets transmitted with a `CHECKSUM_PARTIAL` on ring i [#accel]_. + - Acceleration + + * - `tx[i]_csum_partial_inner` + - Packets transmitted with inner encapsulation with a `CHECKSUM_PARTIAL` on + ring i [#accel]_. + - Acceleration + + * - `tx[i]_csum_none` + - Packets transmitted with no hardware checksum acceleration on ring i. + - Informative + + * - `tx[i]_stopped` / `tx_queue_stopped` [#ring_global]_ + - Events where SQ was full on ring i. If this counter is increased, check + the amount of buffers allocated for transmission. + - Informative + + * - `tx[i]_wake` / `tx_queue_wake` [#ring_global]_ + - Events where SQ was full and has become not full on ring i. + - Informative + + * - `tx[i]_dropped` / `tx_queue_dropped` [#ring_global]_ + - Packets transmitted that were dropped due to DMA mapping failure on + ring i. If this counter is increased, check the amount of buffers + allocated for transmission. + - Error + + * - `tx[i]_nop` + - The number of nop WQEs (empty WQEs) inserted to the SQ (related to + ring i) due to the reach of the end of the cyclic buffer. When reaching + near to the end of cyclic buffer the driver may add those empty WQEs to + avoid handling a state the a WQE start in the end of the queue and ends + in the beginning of the queue. This is a normal condition. + - Informative + + * - `tx[i]_added_vlan_packets` + - The number of packets sent where vlan tag insertion was offloaded to the + hardware. + - Acceleration + + * - `rx[i]_removed_vlan_packets` + - The number of packets received where vlan tag stripping was offloaded to + the hardware. + - Acceleration + + * - `rx[i]_wqe_err` + - The number of wrong opcodes received on ring i. + - Error + + * - `rx[i]_mpwqe_frag` + - The number of WQEs that failed to allocate compound page and hence + fragmented MPWQE’s (Multi Packet WQEs) were used on ring i. If this + counter raise, it may suggest that there is no enough memory for large + pages, the driver allocated fragmented pages. This is not abnormal + condition. + - Informative + + * - `rx[i]_mpwqe_filler_cqes` + - The number of filler CQEs events that were issued on ring i. + - Informative + + * - `rx[i]_mpwqe_filler_strides` + - The number of strides consumed by filler CQEs on ring i. + - Informative + + * - `tx[i]_mpwqe_blks` + - The number of send blocks processed from Multi-Packet WQEs (mpwqe). + - Informative + + * - `tx[i]_mpwqe_pkts` + - The number of send packets processed from Multi-Packet WQEs (mpwqe). + - Informative + + * - `rx[i]_cqe_compress_blks` + - The number of receive blocks with CQE compression on ring i [#accel]_. + - Acceleration + + * - `rx[i]_cqe_compress_pkts` + - The number of receive packets with CQE compression on ring i [#accel]_. + - Acceleration + + * - `rx[i]_arfs_add` + - The number of aRFS flow rules added to the device for direct RQ steering + on ring i [#accel]_. + - Acceleration + + * - `rx[i]_arfs_request_in` + - Number of flow rules that have been requested to move into ring i for + direct RQ steering [#accel]_. + - Acceleration + + * - `rx[i]_arfs_request_out` + - Number of flow rules that have been requested to move out of ring i [#accel]_. + - Acceleration + + * - `rx[i]_arfs_expired` + - Number of flow rules that have been expired and removed [#accel]_. + - Acceleration + + * - `rx[i]_arfs_err` + - Number of flow rules that failed to be added to the flow table. + - Error + + * - `rx[i]_recover` + - The number of times the RQ was recovered. + - Error + + * - `tx[i]_xmit_more` + - The number of packets sent with `xmit_more` indication set on the skbuff + (no doorbell). + - Acceleration + + * - `ch[i]_poll` + - The number of invocations of NAPI poll of channel i. + - Informative + + * - `ch[i]_arm` + - The number of times the NAPI poll function completed and armed the + completion queues on channel i. + - Informative + + * - `ch[i]_aff_change` + - The number of times the NAPI poll function explicitly stopped execution + on a CPU due to a change in affinity, on channel i. + - Informative + + * - `ch[i]_events` + - The number of hard interrupt events on the completion queues of channel i. + - Informative + + * - `ch[i]_eq_rearm` + - The number of times the EQ was recovered. + - Error + + * - `ch[i]_force_irq` + - Number of times NAPI is triggered by XSK wakeups by posting a NOP to + ICOSQ. + - Acceleration + + * - `rx[i]_congst_umr` + - The number of times an outstanding UMR request is delayed due to + congestion, on ring i. + - Informative + + * - `rx_pp_alloc_fast` + - Number of successful fast path allocations. + - Informative + + * - `rx_pp_alloc_slow` + - Number of slow path order-0 allocations. + - Informative + + * - `rx_pp_alloc_slow_high_order` + - Number of slow path high order allocations. + - Informative + + * - `rx_pp_alloc_empty` + - Counter is incremented when ptr ring is empty, so a slow path allocation + was forced. + - Informative + + * - `rx_pp_alloc_refill` + - Counter is incremented when an allocation which triggered a refill of the + cache. + - Informative + + * - `rx_pp_alloc_waive` + - Counter is incremented when pages obtained from the ptr ring that cannot + be added to the cache due to a NUMA mismatch. + - Informative + + * - `rx_pp_recycle_cached` + - Counter is incremented when recycling placed page in the page pool cache. + - Informative + + * - `rx_pp_recycle_cache_full` + - Counter is incremented when page pool cache was full. + - Informative + + * - `rx_pp_recycle_ring` + - Counter is incremented when page placed into the ptr ring. + - Informative + + * - `rx_pp_recycle_ring_full` + - Counter is incremented when page released from page pool because the ptr + ring was full. + - Informative + + * - `rx_pp_recycle_released_ref` + - Counter is incremented when page released (and not recycled) because + refcnt > 1. + - Informative + + * - `rx[i]_xsk_buff_alloc_err` + - The number of times allocating an skb or XSK buffer failed in the XSK RQ + context. + - Error + + * - `rx[i]_xdp_tx_xmit` + - The number of packets forwarded back to the port due to XDP program + `XDP_TX` action (bouncing). these packets are not counted by other + software counters. These packets are counted by physical port and vPort + counters. + - Informative + + * - `rx[i]_xdp_tx_mpwqe` + - Number of multi-packet WQEs transmitted by the netdev and `XDP_TX`-ed by + the netdev during the RQ context. + - Acceleration + + * - `rx[i]_xdp_tx_inlnw` + - Number of WQE data segments transmitted where the data could be inlined + in the WQE and then `XDP_TX`-ed during the RQ context. + - Acceleration + + * - `rx[i]_xdp_tx_nops` + - Number of NOP WQEBBs (WQE building blocks) received posted to the XDP SQ. + - Acceleration + + * - `rx[i]_xdp_tx_full` + - The number of packets that should have been forwarded back to the port + due to `XDP_TX` action but were dropped due to full tx queue. These packets + are not counted by other software counters. These packets are counted by + physical port and vPort counters. You may open more rx queues and spread + traffic rx over all queues and/or increase rx ring size. + - Error + + * - `rx[i]_xdp_tx_err` + - The number of times an `XDP_TX` error such as frame too long and frame + too short occurred on `XDP_TX` ring of RX ring. + - Error + + * - `rx[i]_xdp_tx_cqes` / `rx_xdp_tx_cqe` [#ring_global]_ + - The number of completions received on the CQ of the `XDP_TX` ring. + - Informative + + * - `rx[i]_xdp_drop` + - The number of packets dropped due to XDP program `XDP_DROP` action. these + packets are not counted by other software counters. These packets are + counted by physical port and vPort counters. + - Informative + + * - `rx[i]_xdp_redirect` + - The number of times an XDP redirect action was triggered on ring i. + - Acceleration + + * - `tx[i]_xdp_xmit` + - The number of packets redirected to the interface(due to XDP redirect). + These packets are not counted by other software counters. These packets + are counted by physical port and vPort counters. + - Informative + + * - `tx[i]_xdp_full` + - The number of packets redirected to the interface(due to XDP redirect), + but were dropped due to full tx queue. these packets are not counted by + other software counters. you may enlarge tx queues. + - Informative + + * - `tx[i]_xdp_mpwqe` + - Number of multi-packet WQEs offloaded onto the NIC that were + `XDP_REDIRECT`-ed from other netdevs. + - Acceleration + + * - `tx[i]_xdp_inlnw` + - Number of WQE data segments where the data could be inlined in the WQE + where the data segments were `XDP_REDIRECT`-ed from other netdevs. + - Acceleration + + * - `tx[i]_xdp_nops` + - Number of NOP WQEBBs (WQE building blocks) posted to the SQ that were + `XDP_REDIRECT`-ed from other netdevs. + - Acceleration + + * - `tx[i]_xdp_err` + - The number of packets redirected to the interface(due to XDP redirect) + but were dropped due to error such as frame too long and frame too short. + - Error + + * - `tx[i]_xdp_cqes` + - The number of completions received for packets redirected to the + interface(due to XDP redirect) on the CQ. + - Informative + + * - `tx[i]_xsk_xmit` + - The number of packets transmitted using XSK zerocopy functionality. + - Acceleration + + * - `tx[i]_xsk_mpwqe` + - Number of multi-packet WQEs offloaded onto the NIC that were + `XDP_REDIRECT`-ed from other netdevs. + - Acceleration + + * - `tx[i]_xsk_inlnw` + - Number of WQE data segments where the data could be inlined in the WQE + that are transmitted using XSK zerocopy. + - Acceleration + + * - `tx[i]_xsk_full` + - Number of times doorbell is rung in XSK zerocopy mode when SQ is full. + - Error + + * - `tx[i]_xsk_err` + - Number of errors that occurred in XSK zerocopy mode such as if the data + size is larger than the MTU size. + - Error + + * - `tx[i]_xsk_cqes` + - Number of CQEs processed in XSK zerocopy mode. + - Acceleration + + * - `tx_tls_ctx` + - Number of TLS TX HW offload contexts added to device for encryption. + - Acceleration + + * - `tx_tls_del` + - Number of TLS TX HW offload contexts removed from device (connection + closed). + - Acceleration + + * - `tx_tls_pool_alloc` + - Number of times a unit of work is successfully allocated in the TLS HW + offload pool. + - Acceleration + + * - `tx_tls_pool_free` + - Number of times a unit of work is freed in the TLS HW offload pool. + - Acceleration + + * - `rx_tls_ctx` + - Number of TLS RX HW offload contexts added to device for decryption. + - Acceleration + + * - `rx_tls_del` + - Number of TLS RX HW offload contexts deleted from device (connection has + finished). + - Acceleration + + * - `rx[i]_tls_decrypted_packets` + - Number of successfully decrypted RX packets which were part of a TLS + stream. + - Acceleration + + * - `rx[i]_tls_decrypted_bytes` + - Number of TLS payload bytes in RX packets which were successfully + decrypted. + - Acceleration + + * - `rx[i]_tls_resync_req_pkt` + - Number of received TLS packets with a resync request. + - Acceleration + + * - `rx[i]_tls_resync_req_start` + - Number of times the TLS async resync request was started. + - Acceleration + + * - `rx[i]_tls_resync_req_end` + - Number of times the TLS async resync request properly ended with + providing the HW tracked tcp-seq. + - Acceleration + + * - `rx[i]_tls_resync_req_skip` + - Number of times the TLS async resync request procedure was started but + not properly ended. + - Error + + * - `rx[i]_tls_resync_res_ok` + - Number of times the TLS resync response call to the driver was + successfully handled. + - Acceleration + + * - `rx[i]_tls_resync_res_retry` + - Number of times the TLS resync response call to the driver was + reattempted when ICOSQ is full. + - Error + + * - `rx[i]_tls_resync_res_skip` + - Number of times the TLS resync response call to the driver was terminated + unsuccessfully. + - Error + + * - `rx[i]_tls_err` + - Number of times when CQE TLS offload was problematic. + - Error + + * - `tx[i]_tls_encrypted_packets` + - The number of send packets that are TLS encrypted by the kernel. + - Acceleration + + * - `tx[i]_tls_encrypted_bytes` + - The number of send bytes that are TLS encrypted by the kernel. + - Acceleration + + * - `tx[i]_tls_ooo` + - Number of times out of order TLS SQE fragments were handled on ring i. + - Acceleration + + * - `tx[i]_tls_dump_packets` + - Number of TLS decrypted packets copied over from NIC over DMA. + - Acceleration + + * - `tx[i]_tls_dump_bytes` + - Number of TLS decrypted bytes copied over from NIC over DMA. + - Acceleration + + * - `tx[i]_tls_resync_bytes` + - Number of TLS bytes requested to be resynchronized in order to be + decrypted. + - Acceleration + + * - `tx[i]_tls_skip_no_sync_data` + - Number of TLS send data that can safely be skipped / do not need to be + decrypted. + - Acceleration + + * - `tx[i]_tls_drop_no_sync_data` + - Number of TLS send data that were dropped due to retransmission of TLS + data. + - Acceleration + + * - `ptp_cq[i]_abort` + - Number of times a CQE has to be skipped in precision time protocol due to + a skew between the port timestamp and CQE timestamp being greater than + 128 seconds. + - Error + + * - `ptp_cq[i]_abort_abs_diff_ns` + - Accumulation of time differences between the port timestamp and CQE + timestamp when the difference is greater than 128 seconds in precision + time protocol. + - Error + + * - `ptp_cq[i]_late_cqe` + - Number of times a CQE has been delivered on the PTP timestamping CQ when + the CQE was not expected since a certain amount of time had elapsed where + the device typically ensures not posting the CQE. + - Error + +.. [#ring_global] The corresponding ring and global counters do not share the + same name (i.e. do not follow the common naming scheme). + +vPort Counters +-------------- +Counters on the NIC port that is connected to a eSwitch. + +.. flat-table:: vPort Counter Table + :widths: 2 3 1 + + * - Counter + - Description + - Type + + * - `rx_vport_unicast_packets` + - Unicast packets received, steered to a port including Raw Ethernet + QP/DPDK traffic, excluding RDMA traffic. + - Informative + + * - `rx_vport_unicast_bytes` + - Unicast bytes received, steered to a port including Raw Ethernet QP/DPDK + traffic, excluding RDMA traffic. + - Informative + + * - `tx_vport_unicast_packets` + - Unicast packets transmitted, steered from a port including Raw Ethernet + QP/DPDK traffic, excluding RDMA traffic. + - Informative + + * - `tx_vport_unicast_bytes` + - Unicast bytes transmitted, steered from a port including Raw Ethernet + QP/DPDK traffic, excluding RDMA traffic. + - Informative + + * - `rx_vport_multicast_packets` + - Multicast packets received, steered to a port including Raw Ethernet + QP/DPDK traffic, excluding RDMA traffic. + - Informative + + * - `rx_vport_multicast_bytes` + - Multicast bytes received, steered to a port including Raw Ethernet + QP/DPDK traffic, excluding RDMA traffic. + - Informative + + * - `tx_vport_multicast_packets` + - Multicast packets transmitted, steered from a port including Raw Ethernet + QP/DPDK traffic, excluding RDMA traffic. + - Informative + + * - `tx_vport_multicast_bytes` + - Multicast bytes transmitted, steered from a port including Raw Ethernet + QP/DPDK traffic, excluding RDMA traffic. + - Informative + + * - `rx_vport_broadcast_packets` + - Broadcast packets received, steered to a port including Raw Ethernet + QP/DPDK traffic, excluding RDMA traffic. + - Informative + + * - `rx_vport_broadcast_bytes` + - Broadcast bytes received, steered to a port including Raw Ethernet + QP/DPDK traffic, excluding RDMA traffic. + - Informative + + * - `tx_vport_broadcast_packets` + - Broadcast packets transmitted, steered from a port including Raw Ethernet + QP/DPDK traffic, excluding RDMA traffic. + - Informative + + * - `tx_vport_broadcast_bytes` + - Broadcast bytes transmitted, steered from a port including Raw Ethernet + QP/DPDK traffic, excluding RDMA traffic. + - Informative + + * - `rx_vport_rdma_unicast_packets` + - RDMA unicast packets received, steered to a port (counters counts + RoCE/UD/RC traffic) [#accel]_. + - Acceleration + + * - `rx_vport_rdma_unicast_bytes` + - RDMA unicast bytes received, steered to a port (counters counts + RoCE/UD/RC traffic) [#accel]_. + - Acceleration + + * - `tx_vport_rdma_unicast_packets` + - RDMA unicast packets transmitted, steered from a port (counters counts + RoCE/UD/RC traffic) [#accel]_. + - Acceleration + + * - `tx_vport_rdma_unicast_bytes` + - RDMA unicast bytes transmitted, steered from a port (counters counts + RoCE/UD/RC traffic) [#accel]_. + - Acceleration + + * - `rx_vport_rdma_multicast_packets` + - RDMA multicast packets received, steered to a port (counters counts + RoCE/UD/RC traffic) [#accel]_. + - Acceleration + + * - `rx_vport_rdma_multicast_bytes` + - RDMA multicast bytes received, steered to a port (counters counts + RoCE/UD/RC traffic) [#accel]_. + - Acceleration + + * - `tx_vport_rdma_multicast_packets` + - RDMA multicast packets transmitted, steered from a port (counters counts + RoCE/UD/RC traffic) [#accel]_. + - Acceleration + + * - `tx_vport_rdma_multicast_bytes` + - RDMA multicast bytes transmitted, steered from a port (counters counts + RoCE/UD/RC traffic) [#accel]_. + - Acceleration + + * - `vport_loopback_packets` + - Unicast, multicast and broadcast packets that were loop-back (received + and transmitted), IB/Eth [#accel]_. + - Acceleration + + * - `vport_loopback_bytes` + - Unicast, multicast and broadcast bytes that were loop-back (received + and transmitted), IB/Eth [#accel]_. + - Acceleration + + * - `rx_steer_missed_packets` + - Number of packets that was received by the NIC, however was discarded + because it did not match any flow in the NIC flow table. + - Error + + * - `rx_packets` + - Representor only: packets received, that were handled by the hypervisor. + - Informative + + * - `rx_bytes` + - Representor only: bytes received, that were handled by the hypervisor. + - Informative + + * - `tx_packets` + - Representor only: packets transmitted, that were handled by the + hypervisor. + - Informative + + * - `tx_bytes` + - Representor only: bytes transmitted, that were handled by the hypervisor. + - Informative + + * - `dev_internal_queue_oob` + - The number of dropped packets due to lack of receive WQEs for an internal + device RQ. + - Error + +Physical Port Counters +---------------------- +The physical port counters are the counters on the external port connecting the +adapter to the network. This measuring point holds information on standardized +counters like IEEE 802.3, RFC2863, RFC 2819, RFC 3635 and additional counters +like flow control, FEC and more. + +.. flat-table:: Physical Port Counter Table + :widths: 2 3 1 + + * - Counter + - Description + - Type + + * - `rx_packets_phy` + - The number of packets received on the physical port. This counter doesn’t + include packets that were discarded due to FCS, frame size and similar + errors. + - Informative + + * - `tx_packets_phy` + - The number of packets transmitted on the physical port. + - Informative + + * - `rx_bytes_phy` + - The number of bytes received on the physical port, including Ethernet + header and FCS. + - Informative + + * - `tx_bytes_phy` + - The number of bytes transmitted on the physical port. + - Informative + + * - `rx_multicast_phy` + - The number of multicast packets received on the physical port. + - Informative + + * - `tx_multicast_phy` + - The number of multicast packets transmitted on the physical port. + - Informative + + * - `rx_broadcast_phy` + - The number of broadcast packets received on the physical port. + - Informative + + * - `tx_broadcast_phy` + - The number of broadcast packets transmitted on the physical port. + - Informative + + * - `rx_crc_errors_phy` + - The number of dropped received packets due to FCS (Frame Check Sequence) + error on the physical port. If this counter is increased in high rate, + check the link quality using `rx_symbol_error_phy` and + `rx_corrected_bits_phy` counters below. + - Error + + * - `rx_in_range_len_errors_phy` + - The number of received packets dropped due to length/type errors on a + physical port. + - Error + + * - `rx_out_of_range_len_phy` + - The number of received packets dropped due to length greater than allowed + on a physical port. If this counter is increasing, it implies that the + peer connected to the adapter has a larger MTU configured. Using same MTU + configuration shall resolve this issue. + - Error + + * - `rx_oversize_pkts_phy` + - The number of dropped received packets due to length which exceed MTU + size on a physical port. If this counter is increasing, it implies that + the peer connected to the adapter has a larger MTU configured. Using same + MTU configuration shall resolve this issue. + - Error + + * - `rx_symbol_err_phy` + - The number of received packets dropped due to physical coding errors + (symbol errors) on a physical port. + - Error + + * - `rx_mac_control_phy` + - The number of MAC control packets received on the physical port. + - Informative + + * - `tx_mac_control_phy` + - The number of MAC control packets transmitted on the physical port. + - Informative + + * - `rx_pause_ctrl_phy` + - The number of link layer pause packets received on a physical port. If + this counter is increasing, it implies that the network is congested and + cannot absorb the traffic coming from to the adapter. + - Informative + + * - `tx_pause_ctrl_phy` + - The number of link layer pause packets transmitted on a physical port. If + this counter is increasing, it implies that the NIC is congested and + cannot absorb the traffic coming from the network. + - Informative + + * - `rx_unsupported_op_phy` + - The number of MAC control packets received with unsupported opcode on a + physical port. + - Error + + * - `rx_discards_phy` + - The number of received packets dropped due to lack of buffers on a + physical port. If this counter is increasing, it implies that the adapter + is congested and cannot absorb the traffic coming from the network. + - Error + + * - `tx_discards_phy` + - The number of packets which were discarded on transmission, even no + errors were detected. the drop might occur due to link in down state, + head of line drop, pause from the network, etc. + - Error + + * - `tx_errors_phy` + - The number of transmitted packets dropped due to a length which exceed + MTU size on a physical port. + - Error + + * - `rx_undersize_pkts_phy` + - The number of received packets dropped due to length which is shorter + than 64 bytes on a physical port. If this counter is increasing, it + implies that the peer connected to the adapter has a non-standard MTU + configured or malformed packet had arrived. + - Error + + * - `rx_fragments_phy` + - The number of received packets dropped due to a length which is shorter + than 64 bytes and has FCS error on a physical port. If this counter is + increasing, it implies that the peer connected to the adapter has a + non-standard MTU configured. + - Error + + * - `rx_jabbers_phy` + - The number of received packets d due to a length which is longer than 64 + bytes and had FCS error on a physical port. + - Error + + * - `rx_64_bytes_phy` + - The number of packets received on the physical port with size of 64 bytes. + - Informative + + * - `rx_65_to_127_bytes_phy` + - The number of packets received on the physical port with size of 65 to + 127 bytes. + - Informative + + * - `rx_128_to_255_bytes_phy` + - The number of packets received on the physical port with size of 128 to + 255 bytes. + - Informative + + * - `rx_256_to_511_bytes_phy` + - The number of packets received on the physical port with size of 256 to + 512 bytes. + - Informative + + * - `rx_512_to_1023_bytes_phy` + - The number of packets received on the physical port with size of 512 to + 1023 bytes. + - Informative + + * - `rx_1024_to_1518_bytes_phy` + - The number of packets received on the physical port with size of 1024 to + 1518 bytes. + - Informative + + * - `rx_1519_to_2047_bytes_phy` + - The number of packets received on the physical port with size of 1519 to + 2047 bytes. + - Informative + + * - `rx_2048_to_4095_bytes_phy` + - The number of packets received on the physical port with size of 2048 to + 4095 bytes. + - Informative + + * - `rx_4096_to_8191_bytes_phy` + - The number of packets received on the physical port with size of 4096 to + 8191 bytes. + - Informative + + * - `rx_8192_to_10239_bytes_phy` + - The number of packets received on the physical port with size of 8192 to + 10239 bytes. + - Informative + + * - `link_down_events_phy` + - The number of times where the link operative state changed to down. In + case this counter is increasing it may imply on port flapping. You may + need to replace the cable/transceiver. + - Error + + * - `rx_out_of_buffer` + - Number of times receive queue had no software buffers allocated for the + adapter's incoming traffic. + - Error + + * - `module_bus_stuck` + - The number of times that module's I\ :sup:`2`\C bus (data or clock) + short-wire was detected. You may need to replace the cable/transceiver. + - Error + + * - `module_high_temp` + - The number of times that the module temperature was too high. If this + issue persist, you may need to check the ambient temperature or replace + the cable/transceiver module. + - Error + + * - `module_bad_shorted` + - The number of times that the module cables were shorted. You may need to + replace the cable/transceiver module. + - Error + + * - `module_unplug` + - The number of times that module was ejected. + - Informative + + * - `rx_buffer_passed_thres_phy` + - The number of events where the port receive buffer was over 85% full. + - Informative + + * - `tx_pause_storm_warning_events` + - The number of times the device was sending pauses for a long period of + time. + - Informative + + * - `tx_pause_storm_error_events` + - The number of times the device was sending pauses for a long period of + time, reaching time out and disabling transmission of pause frames. on + the period where pause frames were disabled, drop could have been + occurred. + - Error + + * - `rx[i]_buff_alloc_err` + - Failed to allocate a buffer to received packet (or SKB) on ring i. + - Error + + * - `rx_bits_phy` + - This counter provides information on the total amount of traffic that + could have been received and can be used as a guideline to measure the + ratio of errored traffic in `rx_pcs_symbol_err_phy` and + `rx_corrected_bits_phy`. + - Informative + + * - `rx_pcs_symbol_err_phy` + - This counter counts the number of symbol errors that wasn’t corrected by + FEC correction algorithm or that FEC algorithm was not active on this + interface. If this counter is increasing, it implies that the link + between the NIC and the network is suffering from high BER, and that + traffic is lost. You may need to replace the cable/transceiver. The error + rate is the number of `rx_pcs_symbol_err_phy` divided by the number of + `rx_bits_phy` on a specific time frame. + - Error + + * - `rx_corrected_bits_phy` + - The number of corrected bits on this port according to active FEC + (RS/FC). If this counter is increasing, it implies that the link between + the NIC and the network is suffering from high BER. The corrected bit + rate is the number of `rx_corrected_bits_phy` divided by the number of + `rx_bits_phy` on a specific time frame. + - Error + + * - `rx_err_lane_[l]_phy` + - This counter counts the number of physical raw errors per lane l index. + The counter counts errors before FEC corrections. If this counter is + increasing, it implies that the link between the NIC and the network is + suffering from high BER, and that traffic might be lost. You may need to + replace the cable/transceiver. Please check in accordance with + `rx_corrected_bits_phy`. + - Error + + * - `rx_global_pause` + - The number of pause packets received on the physical port. If this + counter is increasing, it implies that the network is congested and + cannot absorb the traffic coming from the adapter. Note: This counter is + only enabled when global pause mode is enabled. + - Informative + + * - `rx_global_pause_duration` + - The duration of pause received (in microSec) on the physical port. The + counter represents the time the port did not send any traffic. If this + counter is increasing, it implies that the network is congested and + cannot absorb the traffic coming from the adapter. Note: This counter is + only enabled when global pause mode is enabled. + - Informative + + * - `tx_global_pause` + - The number of pause packets transmitted on a physical port. If this + counter is increasing, it implies that the adapter is congested and + cannot absorb the traffic coming from the network. Note: This counter is + only enabled when global pause mode is enabled. + - Informative + + * - `tx_global_pause_duration` + - The duration of pause transmitter (in microSec) on the physical port. + Note: This counter is only enabled when global pause mode is enabled. + - Informative + + * - `rx_global_pause_transition` + - The number of times a transition from Xoff to Xon on the physical port + has occurred. Note: This counter is only enabled when global pause mode + is enabled. + - Informative + + * - `rx_if_down_packets` + - The number of received packets that were dropped due to interface down. + - Informative + +Priority Port Counters +---------------------- +The following counters are physical port counters that are counted per L2 +priority (0-7). + +**Note:** `p` in the counter name represents the priority. + +.. flat-table:: Priority Port Counter Table + :widths: 2 3 1 + + * - Counter + - Description + - Type + + * - `rx_prio[p]_bytes` + - The number of bytes received with priority p on the physical port. + - Informative + + * - `rx_prio[p]_packets` + - The number of packets received with priority p on the physical port. + - Informative + + * - `tx_prio[p]_bytes` + - The number of bytes transmitted on priority p on the physical port. + - Informative + + * - `tx_prio[p]_packets` + - The number of packets transmitted on priority p on the physical port. + - Informative + + * - `rx_prio[p]_pause` + - The number of pause packets received with priority p on a physical port. + If this counter is increasing, it implies that the network is congested + and cannot absorb the traffic coming from the adapter. Note: This counter + is available only if PFC was enabled on priority p. + - Informative + + * - `rx_prio[p]_pause_duration` + - The duration of pause received (in microSec) on priority p on the + physical port. The counter represents the time the port did not send any + traffic on this priority. If this counter is increasing, it implies that + the network is congested and cannot absorb the traffic coming from the + adapter. Note: This counter is available only if PFC was enabled on + priority p. + - Informative + + * - `rx_prio[p]_pause_transition` + - The number of times a transition from Xoff to Xon on priority p on the + physical port has occurred. Note: This counter is available only if PFC + was enabled on priority p. + - Informative + + * - `tx_prio[p]_pause` + - The number of pause packets transmitted on priority p on a physical port. + If this counter is increasing, it implies that the adapter is congested + and cannot absorb the traffic coming from the network. Note: This counter + is available only if PFC was enabled on priority p. + - Informative + + * - `tx_prio[p]_pause_duration` + - The duration of pause transmitter (in microSec) on priority p on the + physical port. Note: This counter is available only if PFC was enabled on + priority p. + - Informative + + * - `rx_prio[p]_buf_discard` + - The number of packets discarded by device due to lack of per host receive + buffers. + - Informative + + * - `rx_prio[p]_cong_discard` + - The number of packets discarded by device due to per host congestion. + - Informative + + * - `rx_prio[p]_marked` + - The number of packets ecn marked by device due to per host congestion. + - Informative + + * - `rx_prio[p]_discards` + - The number of packets discarded by device due to lack of receive buffers. + - Informative + +Device Counters +--------------- +.. flat-table:: Device Counter Table + :widths: 2 3 1 + + * - Counter + - Description + - Type + + * - `rx_pci_signal_integrity` + - Counts physical layer PCIe signal integrity errors, the number of + transitions to recovery due to Framing errors and CRC (dlp and tlp). If + this counter is raising, try moving the adapter card to a different slot + to rule out a bad PCI slot. Validate that you are running with the latest + firmware available and latest server BIOS version. + - Error + + * - `tx_pci_signal_integrity` + - Counts physical layer PCIe signal integrity errors, the number of + transition to recovery initiated by the other side (moving to recovery + due to getting TS/EIEOS). If this counter is raising, try moving the + adapter card to a different slot to rule out a bad PCI slot. Validate + that you are running with the latest firmware available and latest server + BIOS version. + - Error + + * - `outbound_pci_buffer_overflow` + - The number of packets dropped due to pci buffer overflow. If this counter + is raising in high rate, it might indicate that the receive traffic rate + for a host is larger than the PCIe bus and therefore a congestion occurs. + - Informative + + * - `outbound_pci_stalled_rd` + - The percentage (in the range 0...100) of time within the last second that + the NIC had outbound non-posted reads requests but could not perform the + operation due to insufficient posted credits. + - Informative + + * - `outbound_pci_stalled_wr` + - The percentage (in the range 0...100) of time within the last second that + the NIC had outbound posted writes requests but could not perform the + operation due to insufficient posted credits. + - Informative + + * - `outbound_pci_stalled_rd_events` + - The number of seconds where `outbound_pci_stalled_rd` was above 30%. + - Informative + + * - `outbound_pci_stalled_wr_events` + - The number of seconds where `outbound_pci_stalled_wr` was above 30%. + - Informative + + * - `dev_out_of_buffer` + - The number of times the device owned queue had not enough buffers + allocated. + - Error diff --git a/Documentation/networking/device_drivers/ethernet/mellanox/mlx5/index.rst b/Documentation/networking/device_drivers/ethernet/mellanox/mlx5/index.rst new file mode 100644 index 0000000000..581a91caa5 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/mellanox/mlx5/index.rst @@ -0,0 +1,25 @@ +.. SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB +.. include:: <isonum.txt> + +Mellanox ConnectX(R) mlx5 core VPI Network Driver +================================================= + +:Copyright: |copy| 2019, Mellanox Technologies LTD. +:Copyright: |copy| 2020-2023, NVIDIA CORPORATION & AFFILIATES. All rights reserved. + +Contents: + +.. toctree:: + :maxdepth: 2 + + kconfig + switchdev + tracepoints + counters + +.. only:: subproject and html + + Indices + ======= + + * :ref:`genindex` diff --git a/Documentation/networking/device_drivers/ethernet/mellanox/mlx5/kconfig.rst b/Documentation/networking/device_drivers/ethernet/mellanox/mlx5/kconfig.rst new file mode 100644 index 0000000000..0a42c3395f --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/mellanox/mlx5/kconfig.rst @@ -0,0 +1,168 @@ +.. SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB +.. include:: <isonum.txt> + +======================================= +Enabling the driver and kconfig options +======================================= + +:Copyright: |copy| 2023, NVIDIA CORPORATION & AFFILIATES. All rights reserved. + +| mlx5 core is modular and most of the major mlx5 core driver features can be selected (compiled in/out) +| at build time via kernel Kconfig flags. +| Basic features, ethernet net device rx/tx offloads and XDP, are available with the most basic flags +| CONFIG_MLX5_CORE=y/m and CONFIG_MLX5_CORE_EN=y. +| For the list of advanced features, please see below. + +**CONFIG_MLX5_BRIDGE=(y/n)** + +| Enable :ref:`Ethernet Bridging (BRIDGE) offloading support <mlx5_bridge_offload>`. +| This will provide the ability to add representors of mlx5 uplink and VF +| ports to Bridge and offloading rules for traffic between such ports. +| Supports VLANs (trunk and access modes). + + +**CONFIG_MLX5_CORE=(y/m/n)** (module mlx5_core.ko) + +| The driver can be enabled by choosing CONFIG_MLX5_CORE=y/m in kernel config. +| This will provide mlx5 core driver for mlx5 ulps to interface with (mlx5e, mlx5_ib). + + +**CONFIG_MLX5_CORE_EN=(y/n)** + +| Choosing this option will allow basic ethernet netdevice support with all of the standard rx/tx offloads. +| mlx5e is the mlx5 ulp driver which provides netdevice kernel interface, when chosen, mlx5e will be +| built-in into mlx5_core.ko. + + +**CONFIG_MLX5_CORE_EN_DCB=(y/n)**: + +| Enables `Data Center Bridging (DCB) Support <https://enterprise-support.nvidia.com/s/article/howto-auto-config-pfc-and-ets-on-connectx-4-via-lldp-dcbx>`_. + + +**CONFIG_MLX5_CORE_IPOIB=(y/n)** + +| IPoIB offloads & acceleration support. +| Requires CONFIG_MLX5_CORE_EN to provide an accelerated interface for the rdma +| IPoIB ulp netdevice. + + +**CONFIG_MLX5_CLS_ACT=(y/n)** + +| Enables offload support for TC classifier action (NET_CLS_ACT). +| Works in both native NIC mode and Switchdev SRIOV mode. +| Flow-based classifiers, such as those registered through +| `tc-flower(8)`, are processed by the device, rather than the +| host. Actions that would then overwrite matching classification +| results would then be instant due to the offload. + + +**CONFIG_MLX5_EN_ARFS=(y/n)** + +| Enables Hardware-accelerated receive flow steering (arfs) support, and ntuple filtering. +| https://enterprise-support.nvidia.com/s/article/howto-configure-arfs-on-connectx-4 + + +**CONFIG_MLX5_EN_IPSEC=(y/n)** + +| Enables :ref:`IPSec XFRM cryptography-offload acceleration <xfrm_device>`. + + +**CONFIG_MLX5_EN_MACSEC=(y/n)** + +| Build support for MACsec cryptography-offload acceleration in the NIC. + + +**CONFIG_MLX5_EN_RXNFC=(y/n)** + +| Enables ethtool receive network flow classification, which allows user defined +| flow rules to direct traffic into arbitrary rx queue via ethtool set/get_rxnfc API. + + +**CONFIG_MLX5_EN_TLS=(y/n)** + +| TLS cryptography-offload acceleration. + + +**CONFIG_MLX5_ESWITCH=(y/n)** + +| Ethernet SRIOV E-Switch support in ConnectX NIC. E-Switch provides internal SRIOV packet steering +| and switching for the enabled VFs and PF in two available modes: +| 1) `Legacy SRIOV mode (L2 mac vlan steering based) <https://enterprise-support.nvidia.com/s/article/HowTo-Configure-SR-IOV-for-ConnectX-4-ConnectX-5-ConnectX-6-with-KVM-Ethernet>`_. +| 2) :ref:`Switchdev mode (eswitch offloads) <switchdev>`. + + +**CONFIG_MLX5_FPGA=(y/n)** + +| Build support for the Innova family of network cards by Mellanox Technologies. +| Innova network cards are comprised of a ConnectX chip and an FPGA chip on one board. +| If you select this option, the mlx5_core driver will include the Innova FPGA core and allow +| building sandbox-specific client drivers. + + +**CONFIG_MLX5_INFINIBAND=(y/n/m)** (module mlx5_ib.ko) + +| Provides low-level InfiniBand/RDMA and `RoCE <https://enterprise-support.nvidia.com/s/article/recommended-network-configuration-examples-for-roce-deployment>`_ support. + + +**CONFIG_MLX5_MPFS=(y/n)** + +| Ethernet Multi-Physical Function Switch (MPFS) support in ConnectX NIC. +| MPFs is required for when `Multi-Host <https://www.nvidia.com/en-us/networking/multi-host/>`_ configuration is enabled to allow passing +| user configured unicast MAC addresses to the requesting PF. + + +**CONFIG_MLX5_SF=(y/n)** + +| Build support for subfunction. +| Subfunctons are more light weight than PCI SRIOV VFs. Choosing this option +| will enable support for creating subfunction devices. + + +**CONFIG_MLX5_SF_MANAGER=(y/n)** + +| Build support for subfuction port in the NIC. A Mellanox subfunction +| port is managed through devlink. A subfunction supports RDMA, netdevice +| and vdpa device. It is similar to a SRIOV VF but it doesn't require +| SRIOV support. + + +**CONFIG_MLX5_SW_STEERING=(y/n)** + +| Build support for software-managed steering in the NIC. + + +**CONFIG_MLX5_TC_CT=(y/n)** + +| Support offloading connection tracking rules via tc ct action. + + +**CONFIG_MLX5_TC_SAMPLE=(y/n)** + +| Support offloading sample rules via tc sample action. + + +**CONFIG_MLX5_VDPA=(y/n)** + +| Support library for Mellanox VDPA drivers. Provides code that is +| common for all types of VDPA drivers. The following drivers are planned: +| net, block. + + +**CONFIG_MLX5_VDPA_NET=(y/n)** + +| VDPA network driver for ConnectX6 and newer. Provides offloading +| of virtio net datapath such that descriptors put on the ring will +| be executed by the hardware. It also supports a variety of stateless +| offloads depending on the actual device used and firmware version. + + +**CONFIG_MLX5_VFIO_PCI=(y/n)** + +| This provides migration support for MLX5 devices using the VFIO framework. + + +**External options** ( Choose if the corresponding mlx5 feature is required ) + +- CONFIG_MLXFW: When chosen, mlx5 firmware flashing support will be enabled (via devlink and ethtool). +- CONFIG_PTP_1588_CLOCK: When chosen, mlx5 ptp support will be enabled +- CONFIG_VXLAN: When chosen, mlx5 vxlan support will be enabled. diff --git a/Documentation/networking/device_drivers/ethernet/mellanox/mlx5/switchdev.rst b/Documentation/networking/device_drivers/ethernet/mellanox/mlx5/switchdev.rst new file mode 100644 index 0000000000..b617e93d7c --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/mellanox/mlx5/switchdev.rst @@ -0,0 +1,281 @@ +.. SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB +.. include:: <isonum.txt> + +========= +Switchdev +========= + +:Copyright: |copy| 2023, NVIDIA CORPORATION & AFFILIATES. All rights reserved. + +.. _mlx5_bridge_offload: + +Bridge offload +============== + +The mlx5 driver implements support for offloading bridge rules when in switchdev +mode. Linux bridge FDBs are automatically offloaded when mlx5 switchdev +representor is attached to bridge. + +- Change device to switchdev mode:: + + $ devlink dev eswitch set pci/0000:06:00.0 mode switchdev + +- Attach mlx5 switchdev representor 'enp8s0f0' to bridge netdev 'bridge1':: + + $ ip link set enp8s0f0 master bridge1 + +VLANs +----- + +Following bridge VLAN functions are supported by mlx5: + +- VLAN filtering (including multiple VLANs per port):: + + $ ip link set bridge1 type bridge vlan_filtering 1 + $ bridge vlan add dev enp8s0f0 vid 2-3 + +- VLAN push on bridge ingress:: + + $ bridge vlan add dev enp8s0f0 vid 3 pvid + +- VLAN pop on bridge egress:: + + $ bridge vlan add dev enp8s0f0 vid 3 untagged + +Subfunction +=========== + +Subfunction which are spawned over the E-switch are created only with devlink +device, and by default all the SF auxiliary devices are disabled. +This will allow user to configure the SF before the SF have been fully probed, +which will save time. + +Usage example: + +- Create SF:: + + $ devlink port add pci/0000:08:00.0 flavour pcisf pfnum 0 sfnum 11 + $ devlink port function set pci/0000:08:00.0/32768 hw_addr 00:00:00:00:00:11 state active + +- Enable ETH auxiliary device:: + + $ devlink dev param set auxiliary/mlx5_core.sf.1 name enable_eth value true cmode driverinit + +- Now, in order to fully probe the SF, use devlink reload:: + + $ devlink dev reload auxiliary/mlx5_core.sf.1 + +mlx5 supports ETH,rdma and vdpa (vnet) auxiliary devices devlink params (see :ref:`Documentation/networking/devlink/devlink-params.rst <devlink_params_generic>`). + +mlx5 supports subfunction management using devlink port (see :ref:`Documentation/networking/devlink/devlink-port.rst <devlink_port>`) interface. + +A subfunction has its own function capabilities and its own resources. This +means a subfunction has its own dedicated queues (txq, rxq, cq, eq). These +queues are neither shared nor stolen from the parent PCI function. + +When a subfunction is RDMA capable, it has its own QP1, GID table, and RDMA +resources neither shared nor stolen from the parent PCI function. + +A subfunction has a dedicated window in PCI BAR space that is not shared +with the other subfunctions or the parent PCI function. This ensures that all +devices (netdev, rdma, vdpa, etc.) of the subfunction accesses only assigned +PCI BAR space. + +A subfunction supports eswitch representation through which it supports tc +offloads. The user configures eswitch to send/receive packets from/to +the subfunction port. + +Subfunctions share PCI level resources such as PCI MSI-X IRQs with +other subfunctions and/or with its parent PCI function. + +Example mlx5 software, system, and device view:: + + _______ + | admin | + | user |---------- + |_______| | + | | + ____|____ __|______ _________________ + | | | | | | + | devlink | | tc tool | | user | + | tool | |_________| | applications | + |_________| | |_________________| + | | | | + | | | | Userspace + +---------|-------------|-------------------|----------|--------------------+ + | | +----------+ +----------+ Kernel + | | | netdev | | rdma dev | + | | +----------+ +----------+ + (devlink port add/del | ^ ^ + port function set) | | | + | | +---------------| + _____|___ | | _______|_______ + | | | | | mlx5 class | + | devlink | +------------+ | | drivers | + | kernel | | rep netdev | | |(mlx5_core,ib) | + |_________| +------------+ | |_______________| + | | | ^ + (devlink ops) | | (probe/remove) + _________|________ | | ____|________ + | subfunction | | +---------------+ | subfunction | + | management driver|----- | subfunction |---| driver | + | (mlx5_core) | | auxiliary dev | | (mlx5_core) | + |__________________| +---------------+ |_____________| + | ^ + (sf add/del, vhca events) | + | (device add/del) + _____|____ ____|________ + | | | subfunction | + | PCI NIC |--- activate/deactivate events--->| host driver | + |__________| | (mlx5_core) | + |_____________| + +Subfunction is created using devlink port interface. + +- Change device to switchdev mode:: + + $ devlink dev eswitch set pci/0000:06:00.0 mode switchdev + +- Add a devlink port of subfunction flavour:: + + $ devlink port add pci/0000:06:00.0 flavour pcisf pfnum 0 sfnum 88 + pci/0000:06:00.0/32768: type eth netdev eth6 flavour pcisf controller 0 pfnum 0 sfnum 88 external false splittable false + function: + hw_addr 00:00:00:00:00:00 state inactive opstate detached + +- Show a devlink port of the subfunction:: + + $ devlink port show pci/0000:06:00.0/32768 + pci/0000:06:00.0/32768: type eth netdev enp6s0pf0sf88 flavour pcisf pfnum 0 sfnum 88 + function: + hw_addr 00:00:00:00:00:00 state inactive opstate detached + +- Delete a devlink port of subfunction after use:: + + $ devlink port del pci/0000:06:00.0/32768 + +Function attributes +=================== + +The mlx5 driver provides a mechanism to setup PCI VF/SF function attributes in +a unified way for SmartNIC and non-SmartNIC. + +This is supported only when the eswitch mode is set to switchdev. Port function +configuration of the PCI VF/SF is supported through devlink eswitch port. + +Port function attributes should be set before PCI VF/SF is enumerated by the +driver. + +MAC address setup +----------------- + +mlx5 driver support devlink port function attr mechanism to setup MAC +address. (refer to Documentation/networking/devlink/devlink-port.rst) + +RoCE capability setup +~~~~~~~~~~~~~~~~~~~~~ +Not all mlx5 PCI devices/SFs require RoCE capability. + +When RoCE capability is disabled, it saves 1 Mbytes worth of system memory per +PCI devices/SF. + +mlx5 driver support devlink port function attr mechanism to setup RoCE +capability. (refer to Documentation/networking/devlink/devlink-port.rst) + +migratable capability setup +~~~~~~~~~~~~~~~~~~~~~~~~~~~ +User who wants mlx5 PCI VFs to be able to perform live migration need to +explicitly enable the VF migratable capability. + +mlx5 driver support devlink port function attr mechanism to setup migratable +capability. (refer to Documentation/networking/devlink/devlink-port.rst) + +IPsec crypto capability setup +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +User who wants mlx5 PCI VFs to be able to perform IPsec crypto offloading need +to explicitly enable the VF ipsec_crypto capability. Enabling IPsec capability +for VFs is supported starting with ConnectX6dx devices and above. When a VF has +IPsec capability enabled, any IPsec offloading is blocked on the PF. + +mlx5 driver support devlink port function attr mechanism to setup ipsec_crypto +capability. (refer to Documentation/networking/devlink/devlink-port.rst) + +IPsec packet capability setup +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +User who wants mlx5 PCI VFs to be able to perform IPsec packet offloading need +to explicitly enable the VF ipsec_packet capability. Enabling IPsec capability +for VFs is supported starting with ConnectX6dx devices and above. When a VF has +IPsec capability enabled, any IPsec offloading is blocked on the PF. + +mlx5 driver support devlink port function attr mechanism to setup ipsec_packet +capability. (refer to Documentation/networking/devlink/devlink-port.rst) + +SF state setup +-------------- + +To use the SF, the user must activate the SF using the SF function state +attribute. + +- Get the state of the SF identified by its unique devlink port index:: + + $ devlink port show ens2f0npf0sf88 + pci/0000:06:00.0/32768: type eth netdev ens2f0npf0sf88 flavour pcisf controller 0 pfnum 0 sfnum 88 external false splittable false + function: + hw_addr 00:00:00:00:88:88 state inactive opstate detached + +- Activate the function and verify its state is active:: + + $ devlink port function set ens2f0npf0sf88 state active + + $ devlink port show ens2f0npf0sf88 + pci/0000:06:00.0/32768: type eth netdev ens2f0npf0sf88 flavour pcisf controller 0 pfnum 0 sfnum 88 external false splittable false + function: + hw_addr 00:00:00:00:88:88 state active opstate detached + +Upon function activation, the PF driver instance gets the event from the device +that a particular SF was activated. It's the cue to put the device on bus, probe +it and instantiate the devlink instance and class specific auxiliary devices +for it. + +- Show the auxiliary device and port of the subfunction:: + + $ devlink dev show + devlink dev show auxiliary/mlx5_core.sf.4 + + $ devlink port show auxiliary/mlx5_core.sf.4/1 + auxiliary/mlx5_core.sf.4/1: type eth netdev p0sf88 flavour virtual port 0 splittable false + + $ rdma link show mlx5_0/1 + link mlx5_0/1 state ACTIVE physical_state LINK_UP netdev p0sf88 + + $ rdma dev show + 8: rocep6s0f1: node_type ca fw 16.29.0550 node_guid 248a:0703:00b3:d113 sys_image_guid 248a:0703:00b3:d112 + 13: mlx5_0: node_type ca fw 16.29.0550 node_guid 0000:00ff:fe00:8888 sys_image_guid 248a:0703:00b3:d112 + +- Subfunction auxiliary device and class device hierarchy:: + + mlx5_core.sf.4 + (subfunction auxiliary device) + /\ + / \ + / \ + / \ + / \ + mlx5_core.eth.4 mlx5_core.rdma.4 + (sf eth aux dev) (sf rdma aux dev) + | | + | | + p0sf88 mlx5_0 + (sf netdev) (sf rdma device) + +Additionally, the SF port also gets the event when the driver attaches to the +auxiliary device of the subfunction. This results in changing the operational +state of the function. This provides visibility to the user to decide when is it +safe to delete the SF port for graceful termination of the subfunction. + +- Show the SF port operational state:: + + $ devlink port show ens2f0npf0sf88 + pci/0000:06:00.0/32768: type eth netdev ens2f0npf0sf88 flavour pcisf controller 0 pfnum 0 sfnum 88 external false splittable false + function: + hw_addr 00:00:00:00:88:88 state active opstate attached diff --git a/Documentation/networking/device_drivers/ethernet/mellanox/mlx5/tracepoints.rst b/Documentation/networking/device_drivers/ethernet/mellanox/mlx5/tracepoints.rst new file mode 100644 index 0000000000..da8e53cebb --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/mellanox/mlx5/tracepoints.rst @@ -0,0 +1,229 @@ +.. SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB +.. include:: <isonum.txt> + +=========== +Tracepoints +=========== + +:Copyright: |copy| 2023, NVIDIA CORPORATION & AFFILIATES. All rights reserved. + +mlx5 driver provides internal tracepoints for tracking and debugging using +kernel tracepoints interfaces (refer to Documentation/trace/ftrace.rst). + +For the list of support mlx5 events, check /sys/kernel/tracing/events/mlx5/. + +tc and eswitch offloads tracepoints: + +- mlx5e_configure_flower: trace flower filter actions and cookies offloaded to mlx5:: + + $ echo mlx5:mlx5e_configure_flower >> /sys/kernel/tracing/set_event + $ cat /sys/kernel/tracing/trace + ... + tc-6535 [019] ...1 2672.404466: mlx5e_configure_flower: cookie=0000000067874a55 actions= REDIRECT + +- mlx5e_delete_flower: trace flower filter actions and cookies deleted from mlx5:: + + $ echo mlx5:mlx5e_delete_flower >> /sys/kernel/tracing/set_event + $ cat /sys/kernel/tracing/trace + ... + tc-6569 [010] .N.1 2686.379075: mlx5e_delete_flower: cookie=0000000067874a55 actions= NULL + +- mlx5e_stats_flower: trace flower stats request:: + + $ echo mlx5:mlx5e_stats_flower >> /sys/kernel/tracing/set_event + $ cat /sys/kernel/tracing/trace + ... + tc-6546 [010] ...1 2679.704889: mlx5e_stats_flower: cookie=0000000060eb3d6a bytes=0 packets=0 lastused=4295560217 + +- mlx5e_tc_update_neigh_used_value: trace tunnel rule neigh update value offloaded to mlx5:: + + $ echo mlx5:mlx5e_tc_update_neigh_used_value >> /sys/kernel/tracing/set_event + $ cat /sys/kernel/tracing/trace + ... + kworker/u48:4-8806 [009] ...1 55117.882428: mlx5e_tc_update_neigh_used_value: netdev: ens1f0 IPv4: 1.1.1.10 IPv6: ::ffff:1.1.1.10 neigh_used=1 + +- mlx5e_rep_neigh_update: trace neigh update tasks scheduled due to neigh state change events:: + + $ echo mlx5:mlx5e_rep_neigh_update >> /sys/kernel/tracing/set_event + $ cat /sys/kernel/tracing/trace + ... + kworker/u48:7-2221 [009] ...1 1475.387435: mlx5e_rep_neigh_update: netdev: ens1f0 MAC: 24:8a:07:9a:17:9a IPv4: 1.1.1.10 IPv6: ::ffff:1.1.1.10 neigh_connected=1 + +Bridge offloads tracepoints: + +- mlx5_esw_bridge_fdb_entry_init: trace bridge FDB entry offloaded to mlx5:: + + $ echo mlx5:mlx5_esw_bridge_fdb_entry_init >> set_event + $ cat /sys/kernel/tracing/trace + ... + kworker/u20:9-2217 [003] ...1 318.582243: mlx5_esw_bridge_fdb_entry_init: net_device=enp8s0f0_0 addr=e4:fd:05:08:00:02 vid=0 flags=0 used=0 + +- mlx5_esw_bridge_fdb_entry_cleanup: trace bridge FDB entry deleted from mlx5:: + + $ echo mlx5:mlx5_esw_bridge_fdb_entry_cleanup >> set_event + $ cat /sys/kernel/tracing/trace + ... + ip-2581 [005] ...1 318.629871: mlx5_esw_bridge_fdb_entry_cleanup: net_device=enp8s0f0_1 addr=e4:fd:05:08:00:03 vid=0 flags=0 used=16 + +- mlx5_esw_bridge_fdb_entry_refresh: trace bridge FDB entry offload refreshed in + mlx5:: + + $ echo mlx5:mlx5_esw_bridge_fdb_entry_refresh >> set_event + $ cat /sys/kernel/tracing/trace + ... + kworker/u20:8-3849 [003] ...1 466716: mlx5_esw_bridge_fdb_entry_refresh: net_device=enp8s0f0_0 addr=e4:fd:05:08:00:02 vid=3 flags=0 used=0 + +- mlx5_esw_bridge_vlan_create: trace bridge VLAN object add on mlx5 + representor:: + + $ echo mlx5:mlx5_esw_bridge_vlan_create >> set_event + $ cat /sys/kernel/tracing/trace + ... + ip-2560 [007] ...1 318.460258: mlx5_esw_bridge_vlan_create: vid=1 flags=6 + +- mlx5_esw_bridge_vlan_cleanup: trace bridge VLAN object delete from mlx5 + representor:: + + $ echo mlx5:mlx5_esw_bridge_vlan_cleanup >> set_event + $ cat /sys/kernel/tracing/trace + ... + bridge-2582 [007] ...1 318.653496: mlx5_esw_bridge_vlan_cleanup: vid=2 flags=8 + +- mlx5_esw_bridge_vport_init: trace mlx5 vport assigned with bridge upper + device:: + + $ echo mlx5:mlx5_esw_bridge_vport_init >> set_event + $ cat /sys/kernel/tracing/trace + ... + ip-2560 [007] ...1 318.458915: mlx5_esw_bridge_vport_init: vport_num=1 + +- mlx5_esw_bridge_vport_cleanup: trace mlx5 vport removed from bridge upper + device:: + + $ echo mlx5:mlx5_esw_bridge_vport_cleanup >> set_event + $ cat /sys/kernel/tracing/trace + ... + ip-5387 [000] ...1 573713: mlx5_esw_bridge_vport_cleanup: vport_num=1 + +Eswitch QoS tracepoints: + +- mlx5_esw_vport_qos_create: trace creation of transmit scheduler arbiter for vport:: + + $ echo mlx5:mlx5_esw_vport_qos_create >> /sys/kernel/tracing/set_event + $ cat /sys/kernel/tracing/trace + ... + <...>-23496 [018] .... 73136.838831: mlx5_esw_vport_qos_create: (0000:82:00.0) vport=2 tsar_ix=4 bw_share=0, max_rate=0 group=000000007b576bb3 + +- mlx5_esw_vport_qos_config: trace configuration of transmit scheduler arbiter for vport:: + + $ echo mlx5:mlx5_esw_vport_qos_config >> /sys/kernel/tracing/set_event + $ cat /sys/kernel/tracing/trace + ... + <...>-26548 [023] .... 75754.223823: mlx5_esw_vport_qos_config: (0000:82:00.0) vport=1 tsar_ix=3 bw_share=34, max_rate=10000 group=000000007b576bb3 + +- mlx5_esw_vport_qos_destroy: trace deletion of transmit scheduler arbiter for vport:: + + $ echo mlx5:mlx5_esw_vport_qos_destroy >> /sys/kernel/tracing/set_event + $ cat /sys/kernel/tracing/trace + ... + <...>-27418 [004] .... 76546.680901: mlx5_esw_vport_qos_destroy: (0000:82:00.0) vport=1 tsar_ix=3 + +- mlx5_esw_group_qos_create: trace creation of transmit scheduler arbiter for rate group:: + + $ echo mlx5:mlx5_esw_group_qos_create >> /sys/kernel/tracing/set_event + $ cat /sys/kernel/tracing/trace + ... + <...>-26578 [008] .... 75776.022112: mlx5_esw_group_qos_create: (0000:82:00.0) group=000000008dac63ea tsar_ix=5 + +- mlx5_esw_group_qos_config: trace configuration of transmit scheduler arbiter for rate group:: + + $ echo mlx5:mlx5_esw_group_qos_config >> /sys/kernel/tracing/set_event + $ cat /sys/kernel/tracing/trace + ... + <...>-27303 [020] .... 76461.455356: mlx5_esw_group_qos_config: (0000:82:00.0) group=000000008dac63ea tsar_ix=5 bw_share=100 max_rate=20000 + +- mlx5_esw_group_qos_destroy: trace deletion of transmit scheduler arbiter for group:: + + $ echo mlx5:mlx5_esw_group_qos_destroy >> /sys/kernel/tracing/set_event + $ cat /sys/kernel/tracing/trace + ... + <...>-27418 [006] .... 76547.187258: mlx5_esw_group_qos_destroy: (0000:82:00.0) group=000000007b576bb3 tsar_ix=1 + +SF tracepoints: + +- mlx5_sf_add: trace addition of the SF port:: + + $ echo mlx5:mlx5_sf_add >> /sys/kernel/tracing/set_event + $ cat /sys/kernel/tracing/trace + ... + devlink-9363 [031] ..... 24610.188722: mlx5_sf_add: (0000:06:00.0) port_index=32768 controller=0 hw_id=0x8000 sfnum=88 + +- mlx5_sf_free: trace freeing of the SF port:: + + $ echo mlx5:mlx5_sf_free >> /sys/kernel/tracing/set_event + $ cat /sys/kernel/tracing/trace + ... + devlink-9830 [038] ..... 26300.404749: mlx5_sf_free: (0000:06:00.0) port_index=32768 controller=0 hw_id=0x8000 + +- mlx5_sf_activate: trace activation of the SF port:: + + $ echo mlx5:mlx5_sf_activate >> /sys/kernel/tracing/set_event + $ cat /sys/kernel/tracing/trace + ... + devlink-29841 [008] ..... 3669.635095: mlx5_sf_activate: (0000:08:00.0) port_index=32768 controller=0 hw_id=0x8000 + +- mlx5_sf_deactivate: trace deactivation of the SF port:: + + $ echo mlx5:mlx5_sf_deactivate >> /sys/kernel/tracing/set_event + $ cat /sys/kernel/tracing/trace + ... + devlink-29994 [008] ..... 4015.969467: mlx5_sf_deactivate: (0000:08:00.0) port_index=32768 controller=0 hw_id=0x8000 + +- mlx5_sf_hwc_alloc: trace allocating of the hardware SF context:: + + $ echo mlx5:mlx5_sf_hwc_alloc >> /sys/kernel/tracing/set_event + $ cat /sys/kernel/tracing/trace + ... + devlink-9775 [031] ..... 26296.385259: mlx5_sf_hwc_alloc: (0000:06:00.0) controller=0 hw_id=0x8000 sfnum=88 + +- mlx5_sf_hwc_free: trace freeing of the hardware SF context:: + + $ echo mlx5:mlx5_sf_hwc_free >> /sys/kernel/tracing/set_event + $ cat /sys/kernel/tracing/trace + ... + kworker/u128:3-9093 [046] ..... 24625.365771: mlx5_sf_hwc_free: (0000:06:00.0) hw_id=0x8000 + +- mlx5_sf_hwc_deferred_free: trace deferred freeing of the hardware SF context:: + + $ echo mlx5:mlx5_sf_hwc_deferred_free >> /sys/kernel/tracing/set_event + $ cat /sys/kernel/tracing/trace + ... + devlink-9519 [046] ..... 24624.400271: mlx5_sf_hwc_deferred_free: (0000:06:00.0) hw_id=0x8000 + +- mlx5_sf_update_state: trace state updates for SF contexts:: + + $ echo mlx5:mlx5_sf_update_state >> /sys/kernel/tracing/set_event + $ cat /sys/kernel/tracing/trace + ... + kworker/u20:3-29490 [009] ..... 4141.453530: mlx5_sf_update_state: (0000:08:00.0) port_index=32768 controller=0 hw_id=0x8000 state=2 + +- mlx5_sf_vhca_event: trace SF vhca event and state:: + + $ echo mlx5:mlx5_sf_vhca_event >> /sys/kernel/tracing/set_event + $ cat /sys/kernel/tracing/trace + ... + kworker/u128:3-9093 [046] ..... 24625.365525: mlx5_sf_vhca_event: (0000:06:00.0) hw_id=0x8000 sfnum=88 vhca_state=1 + +- mlx5_sf_dev_add: trace SF device add event:: + + $ echo mlx5:mlx5_sf_dev_add>> /sys/kernel/tracing/set_event + $ cat /sys/kernel/tracing/trace + ... + kworker/u128:3-9093 [000] ..... 24616.524495: mlx5_sf_dev_add: (0000:06:00.0) sfdev=00000000fc5d96fd aux_id=4 hw_id=0x8000 sfnum=88 + +- mlx5_sf_dev_del: trace SF device delete event:: + + $ echo mlx5:mlx5_sf_dev_del >> /sys/kernel/tracing/set_event + $ cat /sys/kernel/tracing/trace + ... + kworker/u128:3-9093 [044] ..... 24624.400749: mlx5_sf_dev_del: (0000:06:00.0) sfdev=00000000fc5d96fd aux_id=4 hw_id=0x8000 sfnum=88 diff --git a/Documentation/networking/device_drivers/ethernet/microsoft/netvsc.rst b/Documentation/networking/device_drivers/ethernet/microsoft/netvsc.rst new file mode 100644 index 0000000000..fc5acd427a --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/microsoft/netvsc.rst @@ -0,0 +1,120 @@ +.. SPDX-License-Identifier: GPL-2.0 + +====================== +Hyper-V network driver +====================== + +Compatibility +============= + +This driver is compatible with Windows Server 2012 R2, 2016 and +Windows 10. + +Features +======== + +Checksum offload +---------------- + The netvsc driver supports checksum offload as long as the + Hyper-V host version does. Windows Server 2016 and Azure + support checksum offload for TCP and UDP for both IPv4 and + IPv6. Windows Server 2012 only supports checksum offload for TCP. + +Receive Side Scaling +-------------------- + Hyper-V supports receive side scaling. For TCP & UDP, packets can + be distributed among available queues based on IP address and port + number. + + For TCP & UDP, we can switch hash level between L3 and L4 by ethtool + command. TCP/UDP over IPv4 and v6 can be set differently. The default + hash level is L4. We currently only allow switching TX hash level + from within the guests. + + On Azure, fragmented UDP packets have high loss rate with L4 + hashing. Using L3 hashing is recommended in this case. + + For example, for UDP over IPv4 on eth0: + + To include UDP port numbers in hashing:: + + ethtool -N eth0 rx-flow-hash udp4 sdfn + + To exclude UDP port numbers in hashing:: + + ethtool -N eth0 rx-flow-hash udp4 sd + + To show UDP hash level:: + + ethtool -n eth0 rx-flow-hash udp4 + +Generic Receive Offload, aka GRO +-------------------------------- + The driver supports GRO and it is enabled by default. GRO coalesces + like packets and significantly reduces CPU usage under heavy Rx + load. + +Large Receive Offload (LRO), or Receive Side Coalescing (RSC) +------------------------------------------------------------- + The driver supports LRO/RSC in the vSwitch feature. It reduces the per packet + processing overhead by coalescing multiple TCP segments when possible. The + feature is enabled by default on VMs running on Windows Server 2019 and + later. It may be changed by ethtool command:: + + ethtool -K eth0 lro on + ethtool -K eth0 lro off + +SR-IOV support +-------------- + Hyper-V supports SR-IOV as a hardware acceleration option. If SR-IOV + is enabled in both the vSwitch and the guest configuration, then the + Virtual Function (VF) device is passed to the guest as a PCI + device. In this case, both a synthetic (netvsc) and VF device are + visible in the guest OS and both NIC's have the same MAC address. + + The VF is enslaved by netvsc device. The netvsc driver will transparently + switch the data path to the VF when it is available and up. + Network state (addresses, firewall, etc) should be applied only to the + netvsc device; the slave device should not be accessed directly in + most cases. The exceptions are if some special queue discipline or + flow direction is desired, these should be applied directly to the + VF slave device. + +Receive Buffer +-------------- + Packets are received into a receive area which is created when device + is probed. The receive area is broken into MTU sized chunks and each may + contain one or more packets. The number of receive sections may be changed + via ethtool Rx ring parameters. + + There is a similar send buffer which is used to aggregate packets + for sending. The send area is broken into chunks, typically of 6144 + bytes, each of section may contain one or more packets. Small + packets are usually transmitted via copy to the send buffer. However, + if the buffer is temporarily exhausted, or the packet to be transmitted is + an LSO packet, the driver will provide the host with pointers to the data + from the SKB. This attempts to achieve a balance between the overhead of + data copy and the impact of remapping VM memory to be accessible by the + host. + +XDP support +----------- + XDP (eXpress Data Path) is a feature that runs eBPF bytecode at the early + stage when packets arrive at a NIC card. The goal is to increase performance + for packet processing, reducing the overhead of SKB allocation and other + upper network layers. + + hv_netvsc supports XDP in native mode, and transparently sets the XDP + program on the associated VF NIC as well. + + Setting / unsetting XDP program on synthetic NIC (netvsc) propagates to + VF NIC automatically. Setting / unsetting XDP program on VF NIC directly + is not recommended, also not propagated to synthetic NIC, and may be + overwritten by setting of synthetic NIC. + + XDP program cannot run with LRO (RSC) enabled, so you need to disable LRO + before running XDP:: + + ethtool -K eth0 lro off + + XDP_REDIRECT action is not yet supported. diff --git a/Documentation/networking/device_drivers/ethernet/neterion/s2io.rst b/Documentation/networking/device_drivers/ethernet/neterion/s2io.rst new file mode 100644 index 0000000000..c5673ec455 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/neterion/s2io.rst @@ -0,0 +1,196 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================================================= +Neterion's (Formerly S2io) Xframe I/II PCI-X 10GbE driver +========================================================= + +Release notes for Neterion's (Formerly S2io) Xframe I/II PCI-X 10GbE driver. + +.. Contents + - 1. Introduction + - 2. Identifying the adapter/interface + - 3. Features supported + - 4. Command line parameters + - 5. Performance suggestions + - 6. Available Downloads + + +1. Introduction +=============== +This Linux driver supports Neterion's Xframe I PCI-X 1.0 and +Xframe II PCI-X 2.0 adapters. It supports several features +such as jumbo frames, MSI/MSI-X, checksum offloads, TSO, UFO and so on. +See below for complete list of features. + +All features are supported for both IPv4 and IPv6. + +2. Identifying the adapter/interface +==================================== + +a. Insert the adapter(s) in your system. +b. Build and load driver:: + + # insmod s2io.ko + +c. View log messages:: + + # dmesg | tail -40 + +You will see messages similar to:: + + eth3: Neterion Xframe I 10GbE adapter (rev 3), Version 2.0.9.1, Intr type INTA + eth4: Neterion Xframe II 10GbE adapter (rev 2), Version 2.0.9.1, Intr type INTA + eth4: Device is on 64 bit 133MHz PCIX(M1) bus + +The above messages identify the adapter type(Xframe I/II), adapter revision, +driver version, interface name(eth3, eth4), Interrupt type(INTA, MSI, MSI-X). +In case of Xframe II, the PCI/PCI-X bus width and frequency are displayed +as well. + +To associate an interface with a physical adapter use "ethtool -p <ethX>". +The corresponding adapter's LED will blink multiple times. + +3. Features supported +===================== +a. Jumbo frames. Xframe I/II supports MTU up to 9600 bytes, + modifiable using ip command. + +b. Offloads. Supports checksum offload(TCP/UDP/IP) on transmit + and receive, TSO. + +c. Multi-buffer receive mode. Scattering of packet across multiple + buffers. Currently driver supports 2-buffer mode which yields + significant performance improvement on certain platforms(SGI Altix, + IBM xSeries). + +d. MSI/MSI-X. Can be enabled on platforms which support this feature + (IA64, Xeon) resulting in noticeable performance improvement(up to 7% + on certain platforms). + +e. Statistics. Comprehensive MAC-level and software statistics displayed + using "ethtool -S" option. + +f. Multi-FIFO/Ring. Supports up to 8 transmit queues and receive rings, + with multiple steering options. + +4. Command line parameters +========================== + +a. tx_fifo_num + Number of transmit queues + +Valid range: 1-8 + +Default: 1 + +b. rx_ring_num + Number of receive rings + +Valid range: 1-8 + +Default: 1 + +c. tx_fifo_len + Size of each transmit queue + +Valid range: Total length of all queues should not exceed 8192 + +Default: 4096 + +d. rx_ring_sz + Size of each receive ring(in 4K blocks) + +Valid range: Limited by memory on system + +Default: 30 + +e. intr_type + Specifies interrupt type. Possible values 0(INTA), 2(MSI-X) + +Valid values: 0, 2 + +Default: 2 + +5. Performance suggestions +========================== + +General: + +a. Set MTU to maximum(9000 for switch setup, 9600 in back-to-back configuration) +b. Set TCP windows size to optimal value. + +For instance, for MTU=1500 a value of 210K has been observed to result in +good performance:: + + # sysctl -w net.ipv4.tcp_rmem="210000 210000 210000" + # sysctl -w net.ipv4.tcp_wmem="210000 210000 210000" + +For MTU=9000, TCP window size of 10 MB is recommended:: + + # sysctl -w net.ipv4.tcp_rmem="10000000 10000000 10000000" + # sysctl -w net.ipv4.tcp_wmem="10000000 10000000 10000000" + +Transmit performance: + +a. By default, the driver respects BIOS settings for PCI bus parameters. + However, you may want to experiment with PCI bus parameters + max-split-transactions(MOST) and MMRBC (use setpci command). + + A MOST value of 2 has been found optimal for Opterons and 3 for Itanium. + + It could be different for your hardware. + + Set MMRBC to 4K**. + + For example you can set + + For opteron:: + + #setpci -d 17d5:* 62=1d + + For Itanium:: + + #setpci -d 17d5:* 62=3d + + For detailed description of the PCI registers, please see Xframe User Guide. + +b. Ensure Transmit Checksum offload is enabled. Use ethtool to set/verify this + parameter. + +c. Turn on TSO(using "ethtool -K"):: + + # ethtool -K <ethX> tso on + +Receive performance: + +a. By default, the driver respects BIOS settings for PCI bus parameters. + However, you may want to set PCI latency timer to 248:: + + #setpci -d 17d5:* LATENCY_TIMER=f8 + + For detailed description of the PCI registers, please see Xframe User Guide. + +b. Use 2-buffer mode. This results in large performance boost on + certain platforms(eg. SGI Altix, IBM xSeries). + +c. Ensure Receive Checksum offload is enabled. Use "ethtool -K ethX" command to + set/verify this option. + +d. Enable NAPI feature(in kernel configuration Device Drivers ---> Network + device support ---> Ethernet (10000 Mbit) ---> S2IO 10Gbe Xframe NIC) to + bring down CPU utilization. + +.. note:: + + For AMD opteron platforms with 8131 chipset, MMRBC=1 and MOST=1 are + recommended as safe parameters. + +For more information, please review the AMD8131 errata at +http://vip.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/ +26310_AMD-8131_HyperTransport_PCI-X_Tunnel_Revision_Guide_rev_3_18.pdf + +6. Support +========== + +For further support please contact either your 10GbE Xframe NIC vendor (IBM, +HP, SGI etc.) diff --git a/Documentation/networking/device_drivers/ethernet/netronome/nfp.rst b/Documentation/networking/device_drivers/ethernet/netronome/nfp.rst new file mode 100644 index 0000000000..650b57742d --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/netronome/nfp.rst @@ -0,0 +1,374 @@ +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +.. include:: <isonum.txt> + +=========================================== +Network Flow Processor (NFP) Kernel Drivers +=========================================== + +:Copyright: |copy| 2019, Netronome Systems, Inc. +:Copyright: |copy| 2022, Corigine, Inc. + +Contents +======== + +- `Overview`_ +- `Acquiring Firmware`_ +- `Devlink Info`_ +- `Configure Device`_ +- `Statistics`_ + +Overview +======== + +This driver supports Netronome and Corigine's line of Network Flow Processor +devices, including the NFP3800, NFP4000, NFP5000, and NFP6000 models, which +are also incorporated in the companies' family of Agilio SmartNICs. The SR-IOV +physical and virtual functions for these devices are supported by the driver. + +Acquiring Firmware +================== + +The NFP3800, NFP4000 and NFP6000 devices require application specific firmware +to function. Application firmware can be located either on the host file system +or in the device flash (if supported by management firmware). + +Firmware files on the host filesystem contain card type (`AMDA-*` string), media +config etc. They should be placed in `/lib/firmware/netronome` directory to +load firmware from the host file system. + +Firmware for basic NIC operation is available in the upstream +`linux-firmware.git` repository. + +A more comprehensive list of firmware can be downloaded from the +`Corigine Support site <https://www.corigine.com/DPUDownload.html>`_. + +Firmware in NVRAM +----------------- + +Recent versions of management firmware supports loading application +firmware from flash when the host driver gets probed. The firmware loading +policy configuration may be used to configure this feature appropriately. + +Devlink or ethtool can be used to update the application firmware on the device +flash by providing the appropriate `nic_AMDA*.nffw` file to the respective +command. Users need to take care to write the correct firmware image for the +card and media configuration to flash. + +Available storage space in flash depends on the card being used. + +Dealing with multiple projects +------------------------------ + +NFP hardware is fully programmable therefore there can be different +firmware images targeting different applications. + +When using application firmware from host, we recommend placing +actual firmware files in application-named subdirectories in +`/lib/firmware/netronome` and linking the desired files, e.g.:: + + $ tree /lib/firmware/netronome/ + /lib/firmware/netronome/ + ├── bpf + │ ├── nic_AMDA0081-0001_1x40.nffw + │ └── nic_AMDA0081-0001_4x10.nffw + ├── flower + │ ├── nic_AMDA0081-0001_1x40.nffw + │ └── nic_AMDA0081-0001_4x10.nffw + ├── nic + │ ├── nic_AMDA0081-0001_1x40.nffw + │ └── nic_AMDA0081-0001_4x10.nffw + ├── nic_AMDA0081-0001_1x40.nffw -> bpf/nic_AMDA0081-0001_1x40.nffw + └── nic_AMDA0081-0001_4x10.nffw -> bpf/nic_AMDA0081-0001_4x10.nffw + + 3 directories, 8 files + +You may need to use hard instead of symbolic links on distributions +which use old `mkinitrd` command instead of `dracut` (e.g. Ubuntu). + +After changing firmware files you may need to regenerate the initramfs +image. Initramfs contains drivers and firmware files your system may +need to boot. Refer to the documentation of your distribution to find +out how to update initramfs. Good indication of stale initramfs +is system loading wrong driver or firmware on boot, but when driver is +later reloaded manually everything works correctly. + +Selecting firmware per device +----------------------------- + +Most commonly all cards on the system use the same type of firmware. +If you want to load a specific firmware image for a specific card, you +can use either the PCI bus address or serial number. The driver will +print which files it's looking for when it recognizes a NFP device:: + + nfp: Looking for firmware file in order of priority: + nfp: netronome/serial-00-12-34-aa-bb-cc-10-ff.nffw: not found + nfp: netronome/pci-0000:02:00.0.nffw: not found + nfp: netronome/nic_AMDA0081-0001_1x40.nffw: found, loading... + +In this case if file (or link) called *serial-00-12-34-aa-bb-5d-10-ff.nffw* +or *pci-0000:02:00.0.nffw* is present in `/lib/firmware/netronome` this +firmware file will take precedence over `nic_AMDA*` files. + +Note that `serial-*` and `pci-*` files are **not** automatically included +in initramfs, you will have to refer to documentation of appropriate tools +to find out how to include them. + +Running firmware version +------------------------ + +The version of the loaded firmware for a particular <netdev> interface, +(e.g. enp4s0), or an interface's port <netdev port> (e.g. enp4s0np0) can +be displayed with the ethtool command:: + + $ ethtool -i <netdev> + +Firmware loading policy +----------------------- + +Firmware loading policy is controlled via three HWinfo parameters +stored as key value pairs in the device flash: + +app_fw_from_flash + Defines which firmware should take precedence, 'Disk' (0), 'Flash' (1) or + the 'Preferred' (2) firmware. When 'Preferred' is selected, the management + firmware makes the decision over which firmware will be loaded by comparing + versions of the flash firmware and the host supplied firmware. + This variable is configurable using the 'fw_load_policy' + devlink parameter. + +abi_drv_reset + Defines if the driver should reset the firmware when + the driver is probed, either 'Disk' (0) if firmware was found on disk, + 'Always' (1) reset or 'Never' (2) reset. Note that the device is always + reset on driver unload if firmware was loaded when the driver was probed. + This variable is configurable using the 'reset_dev_on_drv_probe' + devlink parameter. + +abi_drv_load_ifc + Defines a list of PF devices allowed to load FW on the device. + This variable is not currently user configurable. + +Devlink Info +============ + +The devlink info command displays the running and stored firmware versions +on the device, serial number and board information. + +Devlink info command example (replace PCI address):: + + $ devlink dev info pci/0000:03:00.0 + pci/0000:03:00.0: + driver nfp + serial_number CSAAMDA2001-1003000111 + versions: + fixed: + board.id AMDA2001-1003 + board.rev 01 + board.manufacture CSA + board.model mozart + running: + fw.mgmt 22.10.0-rc3 + fw.cpld 0x1000003 + fw.app nic-22.09.0 + chip.init AMDA-2001-1003 1003000111 + stored: + fw.bundle_id bspbundle_1003000111 + fw.mgmt 22.10.0-rc3 + fw.cpld 0x0 + chip.init AMDA-2001-1003 1003000111 + +Configure Device +================ + +This section explains how to use Agilio SmartNICs running basic NIC firmware. + +Configure interface link-speed +------------------------------ +The following steps explains how to change between 10G mode and 25G mode on +Agilio CX 2x25GbE cards. The changing of port speed must be done in order, +port 0 (p0) must be set to 10G before port 1 (p1) may be set to 10G. + +Down the respective interface(s):: + + $ ip link set dev <netdev port 0> down + $ ip link set dev <netdev port 1> down + +Set interface link-speed to 10G:: + + $ ethtool -s <netdev port 0> speed 10000 + $ ethtool -s <netdev port 1> speed 10000 + +Set interface link-speed to 25G:: + + $ ethtool -s <netdev port 0> speed 25000 + $ ethtool -s <netdev port 1> speed 25000 + +Reload driver for changes to take effect:: + + $ rmmod nfp; modprobe nfp + +Configure interface Maximum Transmission Unit (MTU) +--------------------------------------------------- + +The MTU of interfaces can temporarily be set using the iproute2, ip link or +ifconfig tools. Note that this change will not persist. Setting this via +Network Manager, or another appropriate OS configuration tool, is +recommended as changes to the MTU using Network Manager can be made to +persist. + +Set interface MTU to 9000 bytes:: + + $ ip link set dev <netdev port> mtu 9000 + +It is the responsibility of the user or the orchestration layer to set +appropriate MTU values when handling jumbo frames or utilizing tunnels. For +example, if packets sent from a VM are to be encapsulated on the card and +egress a physical port, then the MTU of the VF should be set to lower than +that of the physical port to account for the extra bytes added by the +additional header. If a setup is expected to see fallback traffic between +the SmartNIC and the kernel then the user should also ensure that the PF MTU +is appropriately set to avoid unexpected drops on this path. + +Configure Forward Error Correction (FEC) modes +---------------------------------------------- + +Agilio SmartNICs support FEC mode configuration, e.g. Auto, Firecode Base-R, +ReedSolomon and Off modes. Each physical port's FEC mode can be set +independently using ethtool. The supported FEC modes for an interface can +be viewed using:: + + $ ethtool <netdev> + +The currently configured FEC mode can be viewed using:: + + $ ethtool --show-fec <netdev> + +To force the FEC mode for a particular port, auto-negotiation must be disabled +(see the `Auto-negotiation`_ section). An example of how to set the FEC mode +to Reed-Solomon is:: + + $ ethtool --set-fec <netdev> encoding rs + +Auto-negotiation +---------------- + +To change auto-negotiation settings, the link must first be put down. After the +link is down, auto-negotiation can be enabled or disabled using:: + + ethtool -s <netdev> autoneg <on|off> + +Statistics +========== + +Following device statistics are available through the ``ethtool -S`` interface: + +.. flat-table:: NFP device statistics + :header-rows: 1 + :widths: 3 1 11 + + * - Name + - ID + - Meaning + + * - dev_rx_discards + - 1 + - Packet can be discarded on the RX path for one of the following reasons: + + * The NIC is not in promisc mode, and the destination MAC address + doesn't match the interfaces' MAC address. + * The received packet is larger than the max buffer size on the host. + I.e. it exceeds the Layer 3 MRU. + * There is no freelist descriptor available on the host for the packet. + It is likely that the NIC couldn't cache one in time. + * A BPF program discarded the packet. + * The datapath drop action was executed. + * The MAC discarded the packet due to lack of ingress buffer space + on the NIC. + + * - dev_rx_errors + - 2 + - A packet can be counted (and dropped) as RX error for the following + reasons: + + * A problem with the VEB lookup (only when SR-IOV is used). + * A physical layer problem that causes Ethernet errors, like FCS or + alignment errors. The cause is usually faulty cables or SFPs. + + * - dev_rx_bytes + - 3 + - Total number of bytes received. + + * - dev_rx_uc_bytes + - 4 + - Unicast bytes received. + + * - dev_rx_mc_bytes + - 5 + - Multicast bytes received. + + * - dev_rx_bc_bytes + - 6 + - Broadcast bytes received. + + * - dev_rx_pkts + - 7 + - Total number of packets received. + + * - dev_rx_mc_pkts + - 8 + - Multicast packets received. + + * - dev_rx_bc_pkts + - 9 + - Broadcast packets received. + + * - dev_tx_discards + - 10 + - A packet can be discarded in the TX direction if the MAC is + being flow controlled and the NIC runs out of TX queue space. + + * - dev_tx_errors + - 11 + - A packet can be counted as TX error (and dropped) for one for the + following reasons: + + * The packet is an LSO segment, but the Layer 3 or Layer 4 offset + could not be determined. Therefore LSO could not continue. + * An invalid packet descriptor was received over PCIe. + * The packet Layer 3 length exceeds the device MTU. + * An error on the MAC/physical layer. Usually due to faulty cables or + SFPs. + * A CTM buffer could not be allocated. + * The packet offset was incorrect and could not be fixed by the NIC. + + * - dev_tx_bytes + - 12 + - Total number of bytes transmitted. + + * - dev_tx_uc_bytes + - 13 + - Unicast bytes transmitted. + + * - dev_tx_mc_bytes + - 14 + - Multicast bytes transmitted. + + * - dev_tx_bc_bytes + - 15 + - Broadcast bytes transmitted. + + * - dev_tx_pkts + - 16 + - Total number of packets transmitted. + + * - dev_tx_mc_pkts + - 17 + - Multicast packets transmitted. + + * - dev_tx_bc_pkts + - 18 + - Broadcast packets transmitted. + +Note that statistics unknown to the driver will be displayed as +``dev_unknown_stat$ID``, where ``$ID`` refers to the second column +above. diff --git a/Documentation/networking/device_drivers/ethernet/pensando/ionic.rst b/Documentation/networking/device_drivers/ethernet/pensando/ionic.rst new file mode 100644 index 0000000000..6ec7d686ef --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/pensando/ionic.rst @@ -0,0 +1,274 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +======================================================== +Linux Driver for the Pensando(R) Ethernet adapter family +======================================================== + +Pensando Linux Ethernet driver. +Copyright(c) 2019 Pensando Systems, Inc + +Contents +======== + +- Identifying the Adapter +- Enabling the driver +- Configuring the driver +- Statistics +- Support + +Identifying the Adapter +======================= + +To find if one or more Pensando PCI Ethernet devices are installed on the +host, check for the PCI devices:: + + $ lspci -d 1dd8: + b5:00.0 Ethernet controller: Device 1dd8:1002 + b6:00.0 Ethernet controller: Device 1dd8:1002 + +If such devices are listed as above, then the ionic.ko driver should find +and configure them for use. There should be log entries in the kernel +messages such as these:: + + $ dmesg | grep ionic + ionic 0000:b5:00.0: 126.016 Gb/s available PCIe bandwidth (8.0 GT/s PCIe x16 link) + ionic 0000:b5:00.0 enp181s0: renamed from eth0 + ionic 0000:b5:00.0 enp181s0: Link up - 100 Gbps + ionic 0000:b6:00.0: 126.016 Gb/s available PCIe bandwidth (8.0 GT/s PCIe x16 link) + ionic 0000:b6:00.0 enp182s0: renamed from eth0 + ionic 0000:b6:00.0 enp182s0: Link up - 100 Gbps + +Driver and firmware version information can be gathered with either of +ethtool or devlink tools:: + + $ ethtool -i enp181s0 + driver: ionic + version: 5.7.0 + firmware-version: 1.8.0-28 + ... + + $ devlink dev info pci/0000:b5:00.0 + pci/0000:b5:00.0: + driver ionic + serial_number FLM18420073 + versions: + fixed: + asic.id 0x0 + asic.rev 0x0 + running: + fw 1.8.0-28 + +See Documentation/networking/devlink/ionic.rst for more information +on the devlink dev info data. + +Enabling the driver +=================== + +The driver is enabled via the standard kernel configuration system, +using the make command:: + + make oldconfig/menuconfig/etc. + +The driver is located in the menu structure at: + + -> Device Drivers + -> Network device support (NETDEVICES [=y]) + -> Ethernet driver support + -> Pensando devices + -> Pensando Ethernet IONIC Support + +Configuring the Driver +====================== + +MTU +--- + +Jumbo frame support is available with a maximum size of 9194 bytes. + +Interrupt coalescing +-------------------- + +Interrupt coalescing can be configured by changing the rx-usecs value with +the "ethtool -C" command. The rx-usecs range is 0-190. The tx-usecs value +reflects the rx-usecs value as they are tied together on the same interrupt. + +SR-IOV +------ + +Minimal SR-IOV support is currently offered and can be enabled by setting +the sysfs 'sriov_numvfs' value, if supported by your particular firmware +configuration. + +Statistics +========== + +Basic hardware stats +-------------------- + +The commands ``netstat -i``, ``ip -s link show``, and ``ifconfig`` show +a limited set of statistics taken directly from firmware. For example:: + + $ ip -s link show enp181s0 + 7: enp181s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 1000 + link/ether 00:ae:cd:00:07:68 brd ff:ff:ff:ff:ff:ff + RX: bytes packets errors dropped overrun mcast + 414 5 0 0 0 0 + TX: bytes packets errors dropped carrier collsns + 1384 18 0 0 0 0 + +ethtool -S +---------- + +The statistics shown from the ``ethtool -S`` command includes a combination of +driver counters and firmware counters, including port and queue specific values. +The driver values are counters computed by the driver, and the firmware values +are gathered by the firmware from the port hardware and passed through the +driver with no further interpretation. + +Driver port specific:: + + tx_packets: 12 + tx_bytes: 964 + rx_packets: 5 + rx_bytes: 414 + tx_tso: 0 + tx_tso_bytes: 0 + tx_csum_none: 12 + tx_csum: 0 + rx_csum_none: 0 + rx_csum_complete: 3 + rx_csum_error: 0 + +Driver queue specific:: + + tx_0_pkts: 3 + tx_0_bytes: 294 + tx_0_clean: 3 + tx_0_dma_map_err: 0 + tx_0_linearize: 0 + tx_0_frags: 0 + tx_0_tso: 0 + tx_0_tso_bytes: 0 + tx_0_csum_none: 3 + tx_0_csum: 0 + tx_0_vlan_inserted: 0 + rx_0_pkts: 2 + rx_0_bytes: 120 + rx_0_dma_map_err: 0 + rx_0_alloc_err: 0 + rx_0_csum_none: 0 + rx_0_csum_complete: 0 + rx_0_csum_error: 0 + rx_0_dropped: 0 + rx_0_vlan_stripped: 0 + +Firmware port specific:: + + hw_tx_dropped: 0 + hw_rx_dropped: 0 + hw_rx_over_errors: 0 + hw_rx_missed_errors: 0 + hw_tx_aborted_errors: 0 + frames_rx_ok: 15 + frames_rx_all: 15 + frames_rx_bad_fcs: 0 + frames_rx_bad_all: 0 + octets_rx_ok: 1290 + octets_rx_all: 1290 + frames_rx_unicast: 10 + frames_rx_multicast: 5 + frames_rx_broadcast: 0 + frames_rx_pause: 0 + frames_rx_bad_length: 0 + frames_rx_undersized: 0 + frames_rx_oversized: 0 + frames_rx_fragments: 0 + frames_rx_jabber: 0 + frames_rx_pripause: 0 + frames_rx_stomped_crc: 0 + frames_rx_too_long: 0 + frames_rx_vlan_good: 3 + frames_rx_dropped: 0 + frames_rx_less_than_64b: 0 + frames_rx_64b: 4 + frames_rx_65b_127b: 11 + frames_rx_128b_255b: 0 + frames_rx_256b_511b: 0 + frames_rx_512b_1023b: 0 + frames_rx_1024b_1518b: 0 + frames_rx_1519b_2047b: 0 + frames_rx_2048b_4095b: 0 + frames_rx_4096b_8191b: 0 + frames_rx_8192b_9215b: 0 + frames_rx_other: 0 + frames_tx_ok: 31 + frames_tx_all: 31 + frames_tx_bad: 0 + octets_tx_ok: 2614 + octets_tx_total: 2614 + frames_tx_unicast: 8 + frames_tx_multicast: 21 + frames_tx_broadcast: 2 + frames_tx_pause: 0 + frames_tx_pripause: 0 + frames_tx_vlan: 0 + frames_tx_less_than_64b: 0 + frames_tx_64b: 4 + frames_tx_65b_127b: 27 + frames_tx_128b_255b: 0 + frames_tx_256b_511b: 0 + frames_tx_512b_1023b: 0 + frames_tx_1024b_1518b: 0 + frames_tx_1519b_2047b: 0 + frames_tx_2048b_4095b: 0 + frames_tx_4096b_8191b: 0 + frames_tx_8192b_9215b: 0 + frames_tx_other: 0 + frames_tx_pri_0: 0 + frames_tx_pri_1: 0 + frames_tx_pri_2: 0 + frames_tx_pri_3: 0 + frames_tx_pri_4: 0 + frames_tx_pri_5: 0 + frames_tx_pri_6: 0 + frames_tx_pri_7: 0 + frames_rx_pri_0: 0 + frames_rx_pri_1: 0 + frames_rx_pri_2: 0 + frames_rx_pri_3: 0 + frames_rx_pri_4: 0 + frames_rx_pri_5: 0 + frames_rx_pri_6: 0 + frames_rx_pri_7: 0 + tx_pripause_0_1us_count: 0 + tx_pripause_1_1us_count: 0 + tx_pripause_2_1us_count: 0 + tx_pripause_3_1us_count: 0 + tx_pripause_4_1us_count: 0 + tx_pripause_5_1us_count: 0 + tx_pripause_6_1us_count: 0 + tx_pripause_7_1us_count: 0 + rx_pripause_0_1us_count: 0 + rx_pripause_1_1us_count: 0 + rx_pripause_2_1us_count: 0 + rx_pripause_3_1us_count: 0 + rx_pripause_4_1us_count: 0 + rx_pripause_5_1us_count: 0 + rx_pripause_6_1us_count: 0 + rx_pripause_7_1us_count: 0 + rx_pause_1us_count: 0 + frames_tx_truncated: 0 + + +Support +======= + +For general Linux networking support, please use the netdev mailing +list, which is monitored by Pensando personnel:: + + netdev@vger.kernel.org + +For more specific support needs, please use the Pensando driver support +email:: + + drivers@pensando.io diff --git a/Documentation/networking/device_drivers/ethernet/smsc/smc9.rst b/Documentation/networking/device_drivers/ethernet/smsc/smc9.rst new file mode 100644 index 0000000000..e5eac896a6 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/smsc/smc9.rst @@ -0,0 +1,48 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================ +SMC 9xxxx Driver +================ + +Revision 0.12 + +3/5/96 + +Copyright 1996 Erik Stahlman + +Released under terms of the GNU General Public License. + +This file contains the instructions and caveats for my SMC9xxx driver. You +should not be using the driver without reading this file. + +Things to note about installation: + + 1. The driver should work on all kernels from 1.2.13 until 1.3.71. + (A kernel patch is supplied for 1.3.71 ) + + 2. If you include this into the kernel, you might need to change some + options, such as for forcing IRQ. + + + 3. To compile as a module, run 'make'. + Make will give you the appropriate options for various kernel support. + + 4. Loading the driver as a module:: + + use: insmod smc9194.o + optional parameters: + io=xxxx : your base address + irq=xx : your irq + ifport=x : 0 for whatever is default + 1 for twisted pair + 2 for AUI ( or BNC on some cards ) + +How to obtain the latest version? + +FTP: + ftp://fenris.campus.vt.edu/smc9/smc9-12.tar.gz + ftp://sfbox.vt.edu/filebox/F/fenris/smc9/smc9-12.tar.gz + + +Contacting me: + erik@mail.vt.edu diff --git a/Documentation/networking/device_drivers/ethernet/stmicro/stmmac.rst b/Documentation/networking/device_drivers/ethernet/stmicro/stmmac.rst new file mode 100644 index 0000000000..5d46e50361 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/stmicro/stmmac.rst @@ -0,0 +1,700 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +============================================================== +Linux Driver for the Synopsys(R) Ethernet Controllers "stmmac" +============================================================== + +Authors: Giuseppe Cavallaro <peppe.cavallaro@st.com>, +Alexandre Torgue <alexandre.torgue@st.com>, Jose Abreu <joabreu@synopsys.com> + +Contents +======== + +- In This Release +- Feature List +- Kernel Configuration +- Command Line Parameters +- Driver Information and Notes +- Debug Information +- Support + +In This Release +=============== + +This file describes the stmmac Linux Driver for all the Synopsys(R) Ethernet +Controllers. + +Currently, this network device driver is for all STi embedded MAC/GMAC +(i.e. 7xxx/5xxx SoCs), SPEAr (arm), Loongson1B (mips) and XILINX XC2V3000 +FF1152AMT0221 D1215994A VIRTEX FPGA board. The Synopsys Ethernet QoS 5.0 IPK +is also supported. + +DesignWare(R) Cores Ethernet MAC 10/100/1000 Universal version 3.70a +(and older) and DesignWare(R) Cores Ethernet Quality-of-Service version 4.0 +(and upper) have been used for developing this driver as well as +DesignWare(R) Cores XGMAC - 10G Ethernet MAC and DesignWare(R) Cores +Enterprise MAC - 100G Ethernet MAC. + +This driver supports both the platform bus and PCI. + +This driver includes support for the following Synopsys(R) DesignWare(R) +Cores Ethernet Controllers and corresponding minimum and maximum versions: + ++-------------------------------+--------------+--------------+--------------+ +| Controller Name | Min. Version | Max. Version | Abbrev. Name | ++===============================+==============+==============+==============+ +| Ethernet MAC Universal | N/A | 3.73a | GMAC | ++-------------------------------+--------------+--------------+--------------+ +| Ethernet Quality-of-Service | 4.00a | N/A | GMAC4+ | ++-------------------------------+--------------+--------------+--------------+ +| XGMAC - 10G Ethernet MAC | 2.10a | N/A | XGMAC2+ | ++-------------------------------+--------------+--------------+--------------+ +| XLGMAC - 100G Ethernet MAC | 2.00a | N/A | XLGMAC2+ | ++-------------------------------+--------------+--------------+--------------+ + +For questions related to hardware requirements, refer to the documentation +supplied with your Ethernet adapter. All hardware requirements listed apply +to use with Linux. + +Feature List +============ + +The following features are available in this driver: + - GMII/MII/RGMII/SGMII/RMII/XGMII/XLGMII Interface + - Half-Duplex / Full-Duplex Operation + - Energy Efficient Ethernet (EEE) + - IEEE 802.3x PAUSE Packets (Flow Control) + - RMON/MIB Counters + - IEEE 1588 Timestamping (PTP) + - Pulse-Per-Second Output (PPS) + - MDIO Clause 22 / Clause 45 Interface + - MAC Loopback + - ARP Offloading + - Automatic CRC / PAD Insertion and Checking + - Checksum Offload for Received and Transmitted Packets + - Standard or Jumbo Ethernet Packets + - Source Address Insertion / Replacement + - VLAN TAG Insertion / Replacement / Deletion / Filtering (HASH and PERFECT) + - Programmable TX and RX Watchdog and Coalesce Settings + - Destination Address Filtering (PERFECT) + - HASH Filtering (Multicast) + - Layer 3 / Layer 4 Filtering + - Remote Wake-Up Detection + - Receive Side Scaling (RSS) + - Frame Preemption for TX and RX + - Programmable Burst Length, Threshold, Queue Size + - Multiple Queues (up to 8) + - Multiple Scheduling Algorithms (TX: WRR, DWRR, WFQ, SP, CBS, EST, TBS; + RX: WRR, SP) + - Flexible RX Parser + - TCP / UDP Segmentation Offload (TSO, USO) + - Split Header (SPH) + - Safety Features (ECC Protection, Data Parity Protection) + - Selftests using Ethtool + +Kernel Configuration +==================== + +The kernel configuration option is ``CONFIG_STMMAC_ETH``: + - ``CONFIG_STMMAC_PLATFORM``: is to enable the platform driver. + - ``CONFIG_STMMAC_PCI``: is to enable the pci driver. + +Command Line Parameters +======================= + +If the driver is built as a module the following optional parameters are used +by entering them on the command line with the modprobe command using this +syntax (e.g. for PCI module):: + + modprobe stmmac_pci [<option>=<VAL1>,<VAL2>,...] + +Driver parameters can be also passed in command line by using:: + + stmmaceth=watchdog:100,chain_mode=1 + +The default value for each parameter is generally the recommended setting, +unless otherwise noted. + +watchdog +-------- +:Valid Range: 5000-None +:Default Value: 5000 + +This parameter overrides the transmit timeout in milliseconds. + +debug +----- +:Valid Range: 0-16 (0=none,...,16=all) +:Default Value: 0 + +This parameter adjusts the level of debug messages displayed in the system +logs. + +phyaddr +------- +:Valid Range: 0-31 +:Default Value: -1 + +This parameter overrides the physical address of the PHY device. + +flow_ctrl +--------- +:Valid Range: 0-3 (0=off,1=rx,2=tx,3=rx/tx) +:Default Value: 3 + +This parameter changes the default Flow Control ability. + +pause +----- +:Valid Range: 0-65535 +:Default Value: 65535 + +This parameter changes the default Flow Control Pause time. + +tc +-- +:Valid Range: 64-256 +:Default Value: 64 + +This parameter changes the default HW FIFO Threshold control value. + +buf_sz +------ +:Valid Range: 1536-16384 +:Default Value: 1536 + +This parameter changes the default RX DMA packet buffer size. + +eee_timer +--------- +:Valid Range: 0-None +:Default Value: 1000 + +This parameter changes the default LPI TX Expiration time in milliseconds. + +chain_mode +---------- +:Valid Range: 0-1 (0=off,1=on) +:Default Value: 0 + +This parameter changes the default mode of operation from Ring Mode to +Chain Mode. + +Driver Information and Notes +============================ + +Transmit Process +---------------- + +The xmit method is invoked when the kernel needs to transmit a packet; it sets +the descriptors in the ring and informs the DMA engine that there is a packet +ready to be transmitted. + +By default, the driver sets the ``NETIF_F_SG`` bit in the features field of +the ``net_device`` structure, enabling the scatter-gather feature. This is +true on chips and configurations where the checksum can be done in hardware. + +Once the controller has finished transmitting the packet, timer will be +scheduled to release the transmit resources. + +Receive Process +--------------- + +When one or more packets are received, an interrupt happens. The interrupts +are not queued, so the driver has to scan all the descriptors in the ring +during the receive process. + +This is based on NAPI, so the interrupt handler signals only if there is work +to be done, and it exits. Then the poll method will be scheduled at some +future point. + +The incoming packets are stored, by the DMA, in a list of pre-allocated socket +buffers in order to avoid the memcpy (zero-copy). + +Interrupt Mitigation +-------------------- + +The driver is able to mitigate the number of its DMA interrupts using NAPI for +the reception on chips older than the 3.50. New chips have an HW RX Watchdog +used for this mitigation. + +Mitigation parameters can be tuned by ethtool. + +WoL +--- + +Wake up on Lan feature through Magic and Unicast frames are supported for the +GMAC, GMAC4/5 and XGMAC core. + +DMA Descriptors +--------------- + +Driver handles both normal and alternate descriptors. The latter has been only +tested on DesignWare(R) Cores Ethernet MAC Universal version 3.41a and later. + +stmmac supports DMA descriptor to operate both in dual buffer (RING) and +linked-list(CHAINED) mode. In RING each descriptor points to two data buffer +pointers whereas in CHAINED mode they point to only one data buffer pointer. +RING mode is the default. + +In CHAINED mode each descriptor will have pointer to next descriptor in the +list, hence creating the explicit chaining in the descriptor itself, whereas +such explicit chaining is not possible in RING mode. + +Extended Descriptors +-------------------- + +The extended descriptors give us information about the Ethernet payload when +it is carrying PTP packets or TCP/UDP/ICMP over IP. These are not available on +GMAC Synopsys(R) chips older than the 3.50. At probe time the driver will +decide if these can be actually used. This support also is mandatory for PTPv2 +because the extra descriptors are used for saving the hardware timestamps and +Extended Status. + +Ethtool Support +--------------- + +Ethtool is supported. For example, driver statistics (including RMON), +internal errors can be taken using:: + + ethtool -S ethX + +Ethtool selftests are also supported. This allows to do some early sanity +checks to the HW using MAC and PHY loopback mechanisms:: + + ethtool -t ethX + +Jumbo and Segmentation Offloading +--------------------------------- + +Jumbo frames are supported and tested for the GMAC. The GSO has been also +added but it's performed in software. LRO is not supported. + +TSO Support +----------- + +TSO (TCP Segmentation Offload) feature is supported by GMAC > 4.x and XGMAC +chip family. When a packet is sent through TCP protocol, the TCP stack ensures +that the SKB provided to the low level driver (stmmac in our case) matches +with the maximum frame len (IP header + TCP header + payload <= 1500 bytes +(for MTU set to 1500)). It means that if an application using TCP want to send +a packet which will have a length (after adding headers) > 1514 the packet +will be split in several TCP packets: The data payload is split and headers +(TCP/IP ..) are added. It is done by software. + +When TSO is enabled, the TCP stack doesn't care about the maximum frame length +and provide SKB packet to stmmac as it is. The GMAC IP will have to perform +the segmentation by it self to match with maximum frame length. + +This feature can be enabled in device tree through ``snps,tso`` entry. + +Energy Efficient Ethernet +------------------------- + +Energy Efficient Ethernet (EEE) enables IEEE 802.3 MAC sublayer along with a +family of Physical layer to operate in the Low Power Idle (LPI) mode. The EEE +mode supports the IEEE 802.3 MAC operation at 100Mbps, 1000Mbps and 1Gbps. + +The LPI mode allows power saving by switching off parts of the communication +device functionality when there is no data to be transmitted & received. +The system on both the side of the link can disable some functionalities and +save power during the period of low-link utilization. The MAC controls whether +the system should enter or exit the LPI mode and communicate this to PHY. + +As soon as the interface is opened, the driver verifies if the EEE can be +supported. This is done by looking at both the DMA HW capability register and +the PHY devices MCD registers. + +To enter in TX LPI mode the driver needs to have a software timer that enable +and disable the LPI mode when there is nothing to be transmitted. + +Precision Time Protocol (PTP) +----------------------------- + +The driver supports the IEEE 1588-2002, Precision Time Protocol (PTP), which +enables precise synchronization of clocks in measurement and control systems +implemented with technologies such as network communication. + +In addition to the basic timestamp features mentioned in IEEE 1588-2002 +Timestamps, new GMAC cores support the advanced timestamp features. +IEEE 1588-2008 can be enabled when configuring the Kernel. + +SGMII/RGMII Support +------------------- + +New GMAC devices provide own way to manage RGMII/SGMII. This information is +available at run-time by looking at the HW capability register. This means +that the stmmac can manage auto-negotiation and link status w/o using the +PHYLIB stuff. In fact, the HW provides a subset of extended registers to +restart the ANE, verify Full/Half duplex mode and Speed. Thanks to these +registers, it is possible to look at the Auto-negotiated Link Parter Ability. + +Physical +-------- + +The driver is compatible with Physical Abstraction Layer to be connected with +PHY and GPHY devices. + +Platform Information +-------------------- + +Several information can be passed through the platform and device-tree. + +:: + + struct plat_stmmacenet_data { + +1) Bus identifier:: + + int bus_id; + +2) PHY Physical Address. If set to -1 the driver will pick the first PHY it +finds:: + + int phy_addr; + +3) PHY Device Interface:: + + int interface; + +4) Specific platform fields for the MDIO bus:: + + struct stmmac_mdio_bus_data *mdio_bus_data; + +5) Internal DMA parameters:: + + struct stmmac_dma_cfg *dma_cfg; + +6) Fixed CSR Clock Range selection:: + + int clk_csr; + +7) HW uses the GMAC core:: + + int has_gmac; + +8) If set the MAC will use Enhanced Descriptors:: + + int enh_desc; + +9) Core is able to perform TX Checksum and/or RX Checksum in HW:: + + int tx_coe; + int rx_coe; + +11) Some HWs are not able to perform the csum in HW for over-sized frames due +to limited buffer sizes. Setting this flag the csum will be done in SW on +JUMBO frames:: + + int bugged_jumbo; + +12) Core has the embedded power module:: + + int pmt; + +13) Force DMA to use the Store and Forward mode or Threshold mode:: + + int force_sf_dma_mode; + int force_thresh_dma_mode; + +15) Force to disable the RX Watchdog feature and switch to NAPI mode:: + + int riwt_off; + +16) Limit the maximum operating speed and MTU:: + + int max_speed; + int maxmtu; + +18) Number of Multicast/Unicast filters:: + + int multicast_filter_bins; + int unicast_filter_entries; + +20) Limit the maximum TX and RX FIFO size:: + + int tx_fifo_size; + int rx_fifo_size; + +21) Use the specified number of TX and RX Queues:: + + u32 rx_queues_to_use; + u32 tx_queues_to_use; + +22) Use the specified TX and RX scheduling algorithm:: + + u8 rx_sched_algorithm; + u8 tx_sched_algorithm; + +23) Internal TX and RX Queue parameters:: + + struct stmmac_rxq_cfg rx_queues_cfg[MTL_MAX_RX_QUEUES]; + struct stmmac_txq_cfg tx_queues_cfg[MTL_MAX_TX_QUEUES]; + +24) This callback is used for modifying some syscfg registers (on ST SoCs) +according to the link speed negotiated by the physical layer:: + + void (*fix_mac_speed)(void *priv, unsigned int speed); + +25) Callbacks used for calling a custom initialization; This is sometimes +necessary on some platforms (e.g. ST boxes) where the HW needs to have set +some PIO lines or system cfg registers. init/exit callbacks should not use +or modify platform data:: + + int (*init)(struct platform_device *pdev, void *priv); + void (*exit)(struct platform_device *pdev, void *priv); + +26) Perform HW setup of the bus. For example, on some ST platforms this field +is used to configure the AMBA bridge to generate more efficient STBus traffic:: + + struct mac_device_info *(*setup)(void *priv); + void *bsp_priv; + +27) Internal clocks and rates:: + + struct clk *stmmac_clk; + struct clk *pclk; + struct clk *clk_ptp_ref; + unsigned int clk_ptp_rate; + unsigned int clk_ref_rate; + s32 ptp_max_adj; + +28) Main reset:: + + struct reset_control *stmmac_rst; + +29) AXI Internal Parameters:: + + struct stmmac_axi *axi; + +30) HW uses GMAC>4 cores:: + + int has_gmac4; + +31) HW is sun8i based:: + + bool has_sun8i; + +32) Enables TSO feature:: + + bool tso_en; + +33) Enables Receive Side Scaling (RSS) feature:: + + int rss_en; + +34) MAC Port selection:: + + int mac_port_sel_speed; + +35) Enables TX LPI Clock Gating:: + + bool en_tx_lpi_clockgating; + +36) HW uses XGMAC>2.10 cores:: + + int has_xgmac; + +:: + + } + +For MDIO bus data, we have: + +:: + + struct stmmac_mdio_bus_data { + +1) PHY mask passed when MDIO bus is registered:: + + unsigned int phy_mask; + +2) List of IRQs, one per PHY:: + + int *irqs; + +3) If IRQs is NULL, use this for probed PHY:: + + int probed_phy_irq; + +4) Set to true if PHY needs reset:: + + bool needs_reset; + +:: + + } + +For DMA engine configuration, we have: + +:: + + struct stmmac_dma_cfg { + +1) Programmable Burst Length (TX and RX):: + + int pbl; + +2) If set, DMA TX / RX will use this value rather than pbl:: + + int txpbl; + int rxpbl; + +3) Enable 8xPBL:: + + bool pblx8; + +4) Enable Fixed or Mixed burst:: + + int fixed_burst; + int mixed_burst; + +5) Enable Address Aligned Beats:: + + bool aal; + +6) Enable Enhanced Addressing (> 32 bits):: + + bool eame; + +:: + + } + +For DMA AXI parameters, we have: + +:: + + struct stmmac_axi { + +1) Enable AXI LPI:: + + bool axi_lpi_en; + bool axi_xit_frm; + +2) Set AXI Write / Read maximum outstanding requests:: + + u32 axi_wr_osr_lmt; + u32 axi_rd_osr_lmt; + +3) Set AXI 4KB bursts:: + + bool axi_kbbe; + +4) Set AXI maximum burst length map:: + + u32 axi_blen[AXI_BLEN]; + +5) Set AXI Fixed burst / mixed burst:: + + bool axi_fb; + bool axi_mb; + +6) Set AXI rebuild incrx mode:: + + bool axi_rb; + +:: + + } + +For the RX Queues configuration, we have: + +:: + + struct stmmac_rxq_cfg { + +1) Mode to use (DCB or AVB):: + + u8 mode_to_use; + +2) DMA channel to use:: + + u32 chan; + +3) Packet routing, if applicable:: + + u8 pkt_route; + +4) Use priority routing, and priority to route:: + + bool use_prio; + u32 prio; + +:: + + } + +For the TX Queues configuration, we have: + +:: + + struct stmmac_txq_cfg { + +1) Queue weight in scheduler:: + + u32 weight; + +2) Mode to use (DCB or AVB):: + + u8 mode_to_use; + +3) Credit Base Shaper Parameters:: + + u32 send_slope; + u32 idle_slope; + u32 high_credit; + u32 low_credit; + +4) Use priority scheduling, and priority:: + + bool use_prio; + u32 prio; + +:: + + } + +Device Tree Information +----------------------- + +Please refer to the following document: +Documentation/devicetree/bindings/net/snps,dwmac.yaml + +HW Capabilities +--------------- + +Note that, starting from new chips, where it is available the HW capability +register, many configurations are discovered at run-time for example to +understand if EEE, HW csum, PTP, enhanced descriptor etc are actually +available. As strategy adopted in this driver, the information from the HW +capability register can replace what has been passed from the platform. + +Debug Information +================= + +The driver exports many information i.e. internal statistics, debug +information, MAC and DMA registers etc. + +These can be read in several ways depending on the type of the information +actually needed. + +For example a user can be use the ethtool support to get statistics: e.g. +using: ``ethtool -S ethX`` (that shows the Management counters (MMC) if +supported) or sees the MAC/DMA registers: e.g. using: ``ethtool -d ethX`` + +Compiling the Kernel with ``CONFIG_DEBUG_FS`` the driver will export the +following debugfs entries: + + - ``descriptors_status``: To show the DMA TX/RX descriptor rings + - ``dma_cap``: To show the HW Capabilities + +Developer can also use the ``debug`` module parameter to get further debug +information (please see: NETIF Msg Level). + +Support +======= + +If an issue is identified with the released source code on a supported kernel +with a supported adapter, email the specific information related to the +issue to netdev@vger.kernel.org diff --git a/Documentation/networking/device_drivers/ethernet/ti/am65_nuss_cpsw_switchdev.rst b/Documentation/networking/device_drivers/ethernet/ti/am65_nuss_cpsw_switchdev.rst new file mode 100644 index 0000000000..25fd9aa284 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/ti/am65_nuss_cpsw_switchdev.rst @@ -0,0 +1,143 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=================================================================== +Texas Instruments K3 AM65 CPSW NUSS switchdev based ethernet driver +=================================================================== + +:Version: 1.0 + +Port renaming +============= + +In order to rename via udev:: + + ip -d link show dev sw0p1 | grep switchid + + SUBSYSTEM=="net", ACTION=="add", ATTR{phys_switch_id}==<switchid>, \ + ATTR{phys_port_name}!="", NAME="sw0$attr{phys_port_name}" + + +Multi mac mode +============== + +- The driver is operating in multi-mac mode by default, thus + working as N individual network interfaces. + +Devlink configuration parameters +================================ + +See Documentation/networking/devlink/am65-nuss-cpsw-switch.rst + +Enabling "switch" +================= + +The Switch mode can be enabled by configuring devlink driver parameter +"switch_mode" to 1/true:: + + devlink dev param set platform/c000000.ethernet \ + name switch_mode value true cmode runtime + +This can be done regardless of the state of Port's netdev devices - UP/DOWN, but +Port's netdev devices have to be in UP before joining to the bridge to avoid +overwriting of bridge configuration as CPSW switch driver completely reloads its +configuration when first port changes its state to UP. + +When the both interfaces joined the bridge - CPSW switch driver will enable +marking packets with offload_fwd_mark flag. + +All configuration is implemented via switchdev API. + +Bridge setup +============ + +:: + + devlink dev param set platform/c000000.ethernet \ + name switch_mode value true cmode runtime + + ip link add name br0 type bridge + ip link set dev br0 type bridge ageing_time 1000 + ip link set dev sw0p1 up + ip link set dev sw0p2 up + ip link set dev sw0p1 master br0 + ip link set dev sw0p2 master br0 + + [*] bridge vlan add dev br0 vid 1 pvid untagged self + + [*] if vlan_filtering=1. where default_pvid=1 + + Note. Steps [*] are mandatory. + + +On/off STP +========== + +:: + + ip link set dev BRDEV type bridge stp_state 1/0 + +VLAN configuration +================== + +:: + + bridge vlan add dev br0 vid 1 pvid untagged self <---- add cpu port to VLAN 1 + +Note. This step is mandatory for bridge/default_pvid. + +Add extra VLANs +=============== + + 1. untagged:: + + bridge vlan add dev sw0p1 vid 100 pvid untagged master + bridge vlan add dev sw0p2 vid 100 pvid untagged master + bridge vlan add dev br0 vid 100 pvid untagged self <---- Add cpu port to VLAN100 + + 2. tagged:: + + bridge vlan add dev sw0p1 vid 100 master + bridge vlan add dev sw0p2 vid 100 master + bridge vlan add dev br0 vid 100 pvid tagged self <---- Add cpu port to VLAN100 + +FDBs +---- + +FDBs are automatically added on the appropriate switch port upon detection + +Manually adding FDBs:: + + bridge fdb add aa:bb:cc:dd:ee:ff dev sw0p1 master vlan 100 + bridge fdb add aa:bb:cc:dd:ee:fe dev sw0p2 master <---- Add on all VLANs + +MDBs +---- + +MDBs are automatically added on the appropriate switch port upon detection + +Manually adding MDBs:: + + bridge mdb add dev br0 port sw0p1 grp 239.1.1.1 permanent vid 100 + bridge mdb add dev br0 port sw0p1 grp 239.1.1.1 permanent <---- Add on all VLANs + +Multicast flooding +================== +CPU port mcast_flooding is always on + +Turning flooding on/off on switch ports: +bridge link set dev sw0p1 mcast_flood on/off + +Access and Trunk port +===================== + +:: + + bridge vlan add dev sw0p1 vid 100 pvid untagged master + bridge vlan add dev sw0p2 vid 100 master + + + bridge vlan add dev br0 vid 100 self + ip link add link br0 name br0.100 type vlan id 100 + +Note. Setting PVID on Bridge device itself works only for +default VLAN (default_pvid). diff --git a/Documentation/networking/device_drivers/ethernet/ti/cpsw.rst b/Documentation/networking/device_drivers/ethernet/ti/cpsw.rst new file mode 100644 index 0000000000..a88946bd18 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/ti/cpsw.rst @@ -0,0 +1,587 @@ +.. SPDX-License-Identifier: GPL-2.0 + +====================================== +Texas Instruments CPSW ethernet driver +====================================== + +Multiqueue & CBS & MQPRIO +========================= + + +The cpsw has 3 CBS shapers for each external ports. This document +describes MQPRIO and CBS Qdisc offload configuration for cpsw driver +based on examples. It potentially can be used in audio video bridging +(AVB) and time sensitive networking (TSN). + +The following examples were tested on AM572x EVM and BBB boards. + +Test setup +========== + +Under consideration two examples with AM572x EVM running cpsw driver +in dual_emac mode. + +Several prerequisites: + +- TX queues must be rated starting from txq0 that has highest priority +- Traffic classes are used starting from 0, that has highest priority +- CBS shapers should be used with rated queues +- The bandwidth for CBS shapers has to be set a little bit more then + potential incoming rate, thus, rate of all incoming tx queues has + to be a little less +- Real rates can differ, due to discreetness +- Map skb-priority to txq is not enough, also skb-priority to l2 prio + map has to be created with ip or vconfig tool +- Any l2/socket prio (0 - 7) for classes can be used, but for + simplicity default values are used: 3 and 2 +- only 2 classes tested: A and B, but checked and can work with more, + maximum allowed 4, but only for 3 rate can be set. + +Test setup for examples +======================= + +:: + + +-------------------------------+ + |--+ | + | | Workstation0 | + |E | MAC 18:03:73:66:87:42 | + +-----------------------------+ +--|t | | + | | 1 | E | | |h |./tsn_listener -d \ | + | Target board: | 0 | t |--+ |0 | 18:03:73:66:87:42 -i eth0 \| + | AM572x EVM | 0 | h | | | -s 1500 | + | | 0 | 0 | |--+ | + | Only 2 classes: |Mb +---| +-------------------------------+ + | class A, class B | | + | | +---| +-------------------------------+ + | | 1 | E | |--+ | + | | 0 | t | | | Workstation1 | + | | 0 | h |--+ |E | MAC 20:cf:30:85:7d:fd | + | |Mb | 1 | +--|t | | + +-----------------------------+ |h |./tsn_listener -d \ | + |0 | 20:cf:30:85:7d:fd -i eth0 \| + | | -s 1500 | + |--+ | + +-------------------------------+ + + +Example 1: One port tx AVB configuration scheme for target board +---------------------------------------------------------------- + +(prints and scheme for AM572x evm, applicable for single port boards) + +- tc - traffic class +- txq - transmit queue +- p - priority +- f - fifo (cpsw fifo) +- S - shaper configured + +:: + + +------------------------------------------------------------------+ u + | +---------------+ +---------------+ +------+ +------+ | s + | | | | | | | | | | e + | | App 1 | | App 2 | | Apps | | Apps | | r + | | Class A | | Class B | | Rest | | Rest | | + | | Eth0 | | Eth0 | | Eth0 | | Eth1 | | s + | | VLAN100 | | VLAN100 | | | | | | | | p + | | 40 Mb/s | | 20 Mb/s | | | | | | | | a + | | SO_PRIORITY=3 | | SO_PRIORITY=2 | | | | | | | | c + | | | | | | | | | | | | | | e + | +---|-----------+ +---|-----------+ +---|--+ +---|--+ | + +-----|------------------|------------------|--------|-------------+ + +-+ +------------+ | | + | | +-----------------+ +--+ + | | | | + +---|-------|-------------|-----------------------|----------------+ + | +----+ +----+ +----+ +----+ +----+ | + | | p3 | | p2 | | p1 | | p0 | | p0 | | k + | \ / \ / \ / \ / \ / | e + | \ / \ / \ / \ / \ / | r + | \/ \/ \/ \/ \/ | n + | | | | | | e + | | | +-----+ | | l + | | | | | | + | +----+ +----+ +----+ +----+ | s + | |tc0 | |tc1 | |tc2 | |tc0 | | p + | \ / \ / \ / \ / | a + | \ / \ / \ / \ / | c + | \/ \/ \/ \/ | e + | | | +-----+ | | + | | | | | | | + | | | | | | | + | | | | | | | + | +----+ +----+ +----+ +----+ +----+ | + | |txq0| |txq1| |txq2| |txq3| |txq4| | + | \ / \ / \ / \ / \ / | + | \ / \ / \ / \ / \ / | + | \/ \/ \/ \/ \/ | + | +-|------|------|------|--+ +--|--------------+ | + | | | | | | | Eth0.100 | | Eth1 | | + +---|------|------|------|------------------------|----------------+ + | | | | | + p p p p | + 3 2 0-1, 4-7 <- L2 priority | + | | | | | + | | | | | + +---|------|------|------|------------------------|----------------+ + | | | | | |----------+ | + | +----+ +----+ +----+ +----+ +----+ | + | |dma7| |dma6| |dma5| |dma4| |dma3| | + | \ / \ / \ / \ / \ / | c + | \S / \S / \ / \ / \ / | p + | \/ \/ \/ \/ \/ | s + | | | | +----- | | w + | | | | | | | + | | | | | | | d + | +----+ +----+ +----+p p+----+ | r + | | | | | | |o o| | | i + | | f3 | | f2 | | f0 |r r| f0 | | v + | |tc0 | |tc1 | |tc2 |t t|tc0 | | e + | \CBS / \CBS / \CBS /1 2\CBS / | r + | \S / \S / \ / \ / | + | \/ \/ \/ \/ | + +------------------------------------------------------------------+ + + +1) :: + + + // Add 4 tx queues, for interface Eth0, and 1 tx queue for Eth1 + $ ethtool -L eth0 rx 1 tx 5 + rx unmodified, ignoring + +2) :: + + // Check if num of queues is set correctly: + $ ethtool -l eth0 + Channel parameters for eth0: + Pre-set maximums: + RX: 8 + TX: 8 + Other: 0 + Combined: 0 + Current hardware settings: + RX: 1 + TX: 5 + Other: 0 + Combined: 0 + +3) :: + + // TX queues must be rated starting from 0, so set bws for tx0 and tx1 + // Set rates 40 and 20 Mb/s appropriately. + // Pay attention, real speed can differ a bit due to discreetness. + // Leave last 2 tx queues not rated. + $ echo 40 > /sys/class/net/eth0/queues/tx-0/tx_maxrate + $ echo 20 > /sys/class/net/eth0/queues/tx-1/tx_maxrate + +4) :: + + // Check maximum rate of tx (cpdma) queues: + $ cat /sys/class/net/eth0/queues/tx-*/tx_maxrate + 40 + 20 + 0 + 0 + 0 + +5) :: + + // Map skb->priority to traffic class: + // 3pri -> tc0, 2pri -> tc1, (0,1,4-7)pri -> tc2 + // Map traffic class to transmit queue: + // tc0 -> txq0, tc1 -> txq1, tc2 -> (txq2, txq3) + $ tc qdisc replace dev eth0 handle 100: parent root mqprio num_tc 3 \ + map 2 2 1 0 2 2 2 2 2 2 2 2 2 2 2 2 queues 1@0 1@1 2@2 hw 1 + +5a) :: + + // As two interface sharing same set of tx queues, assign all traffic + // coming to interface Eth1 to separate queue in order to not mix it + // with traffic from interface Eth0, so use separate txq to send + // packets to Eth1, so all prio -> tc0 and tc0 -> txq4 + // Here hw 0, so here still default configuration for eth1 in hw + $ tc qdisc replace dev eth1 handle 100: parent root mqprio num_tc 1 \ + map 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 queues 1@4 hw 0 + +6) :: + + // Check classes settings + $ tc -g class show dev eth0 + +---(100:ffe2) mqprio + | +---(100:3) mqprio + | +---(100:4) mqprio + | + +---(100:ffe1) mqprio + | +---(100:2) mqprio + | + +---(100:ffe0) mqprio + +---(100:1) mqprio + + $ tc -g class show dev eth1 + +---(100:ffe0) mqprio + +---(100:5) mqprio + +7) :: + + // Set rate for class A - 41 Mbit (tc0, txq0) using CBS Qdisc + // Set it +1 Mb for reserve (important!) + // here only idle slope is important, others arg are ignored + // Pay attention, real speed can differ a bit due to discreetness + $ tc qdisc add dev eth0 parent 100:1 cbs locredit -1438 \ + hicredit 62 sendslope -959000 idleslope 41000 offload 1 + net eth0: set FIFO3 bw = 50 + +8) :: + + // Set rate for class B - 21 Mbit (tc1, txq1) using CBS Qdisc: + // Set it +1 Mb for reserve (important!) + $ tc qdisc add dev eth0 parent 100:2 cbs locredit -1468 \ + hicredit 65 sendslope -979000 idleslope 21000 offload 1 + net eth0: set FIFO2 bw = 30 + +9) :: + + // Create vlan 100 to map sk->priority to vlan qos + $ ip link add link eth0 name eth0.100 type vlan id 100 + 8021q: 802.1Q VLAN Support v1.8 + 8021q: adding VLAN 0 to HW filter on device eth0 + 8021q: adding VLAN 0 to HW filter on device eth1 + net eth0: Adding vlanid 100 to vlan filter + +10) :: + + // Map skb->priority to L2 prio, 1 to 1 + $ ip link set eth0.100 type vlan \ + egress 0:0 1:1 2:2 3:3 4:4 5:5 6:6 7:7 + +11) :: + + // Check egress map for vlan 100 + $ cat /proc/net/vlan/eth0.100 + [...] + INGRESS priority mappings: 0:0 1:0 2:0 3:0 4:0 5:0 6:0 7:0 + EGRESS priority mappings: 0:0 1:1 2:2 3:3 4:4 5:5 6:6 7:7 + +12) :: + + // Run your appropriate tools with socket option "SO_PRIORITY" + // to 3 for class A and/or to 2 for class B + // (I took at https://www.spinics.net/lists/netdev/msg460869.html) + ./tsn_talker -d 18:03:73:66:87:42 -i eth0.100 -p3 -s 1500& + ./tsn_talker -d 18:03:73:66:87:42 -i eth0.100 -p2 -s 1500& + +13) :: + + // run your listener on workstation (should be in same vlan) + // (I took at https://www.spinics.net/lists/netdev/msg460869.html) + ./tsn_listener -d 18:03:73:66:87:42 -i enp5s0 -s 1500 + Receiving data rate: 39012 kbps + Receiving data rate: 39012 kbps + Receiving data rate: 39012 kbps + Receiving data rate: 39012 kbps + Receiving data rate: 39012 kbps + Receiving data rate: 39012 kbps + Receiving data rate: 39012 kbps + Receiving data rate: 39012 kbps + Receiving data rate: 39012 kbps + Receiving data rate: 39012 kbps + Receiving data rate: 39012 kbps + Receiving data rate: 39012 kbps + Receiving data rate: 39000 kbps + +14) :: + + // Restore default configuration if needed + $ ip link del eth0.100 + $ tc qdisc del dev eth1 root + $ tc qdisc del dev eth0 root + net eth0: Prev FIFO2 is shaped + net eth0: set FIFO3 bw = 0 + net eth0: set FIFO2 bw = 0 + $ ethtool -L eth0 rx 1 tx 1 + +Example 2: Two port tx AVB configuration scheme for target board +---------------------------------------------------------------- + +(prints and scheme for AM572x evm, for dual emac boards only) + +:: + + +------------------------------------------------------------------+ u + | +----------+ +----------+ +------+ +----------+ +----------+ | s + | | | | | | | | | | | | e + | | App 1 | | App 2 | | Apps | | App 3 | | App 4 | | r + | | Class A | | Class B | | Rest | | Class B | | Class A | | + | | Eth0 | | Eth0 | | | | | Eth1 | | Eth1 | | s + | | VLAN100 | | VLAN100 | | | | | VLAN100 | | VLAN100 | | p + | | 40 Mb/s | | 20 Mb/s | | | | | 10 Mb/s | | 30 Mb/s | | a + | | SO_PRI=3 | | SO_PRI=2 | | | | | SO_PRI=3 | | SO_PRI=2 | | c + | | | | | | | | | | | | | | | | | e + | +---|------+ +---|------+ +---|--+ +---|------+ +---|------+ | + +-----|-------------|-------------|---------|-------------|--------+ + +-+ +-------+ | +----------+ +----+ + | | +-------+------+ | | + | | | | | | + +---|-------|-------------|--------------|-------------|-------|---+ + | +----+ +----+ +----+ +----+ +----+ +----+ +----+ +----+ | + | | p3 | | p2 | | p1 | | p0 | | p0 | | p1 | | p2 | | p3 | | k + | \ / \ / \ / \ / \ / \ / \ / \ / | e + | \ / \ / \ / \ / \ / \ / \ / \ / | r + | \/ \/ \/ \/ \/ \/ \/ \/ | n + | | | | | | | | e + | | | +----+ +----+ | | | l + | | | | | | | | + | +----+ +----+ +----+ +----+ +----+ +----+ | s + | |tc0 | |tc1 | |tc2 | |tc2 | |tc1 | |tc0 | | p + | \ / \ / \ / \ / \ / \ / | a + | \ / \ / \ / \ / \ / \ / | c + | \/ \/ \/ \/ \/ \/ | e + | | | +-----+ +-----+ | | | + | | | | | | | | | | + | | | | | | | | | | + | | | | | E E | | | | | + | +----+ +----+ +----+ +----+ t t +----+ +----+ +----+ +----+ | + | |txq0| |txq1| |txq4| |txq5| h h |txq6| |txq7| |txq3| |txq2| | + | \ / \ / \ / \ / 0 1 \ / \ / \ / \ / | + | \ / \ / \ / \ / . . \ / \ / \ / \ / | + | \/ \/ \/ \/ 1 1 \/ \/ \/ \/ | + | +-|------|------|------|--+ 0 0 +-|------|------|------|--+ | + | | | | | | | 0 0 | | | | | | | + +---|------|------|------|---------------|------|------|------|----+ + | | | | | | | | + p p p p p p p p + 3 2 0-1, 4-7 <-L2 pri-> 0-1, 4-7 2 3 + | | | | | | | | + | | | | | | | | + +---|------|------|------|---------------|------|------|------|----+ + | | | | | | | | | | + | +----+ +----+ +----+ +----+ +----+ +----+ +----+ +----+ | + | |dma7| |dma6| |dma3| |dma2| |dma1| |dma0| |dma4| |dma5| | + | \ / \ / \ / \ / \ / \ / \ / \ / | c + | \S / \S / \ / \ / \ / \ / \S / \S / | p + | \/ \/ \/ \/ \/ \/ \/ \/ | s + | | | | +----- | | | | | w + | | | | | +----+ | | | | + | | | | | | | | | | d + | +----+ +----+ +----+p p+----+ +----+ +----+ | r + | | | | | | |o o| | | | | | | i + | | f3 | | f2 | | f0 |r CPSW r| f3 | | f2 | | f0 | | v + | |tc0 | |tc1 | |tc2 |t t|tc0 | |tc1 | |tc2 | | e + | \CBS / \CBS / \CBS /1 2\CBS / \CBS / \CBS / | r + | \S / \S / \ / \S / \S / \ / | + | \/ \/ \/ \/ \/ \/ | + +------------------------------------------------------------------+ + ========================================Eth==========================> + +1) :: + + // Add 8 tx queues, for interface Eth0, but they are common, so are accessed + // by two interfaces Eth0 and Eth1. + $ ethtool -L eth1 rx 1 tx 8 + rx unmodified, ignoring + +2) :: + + // Check if num of queues is set correctly: + $ ethtool -l eth0 + Channel parameters for eth0: + Pre-set maximums: + RX: 8 + TX: 8 + Other: 0 + Combined: 0 + Current hardware settings: + RX: 1 + TX: 8 + Other: 0 + Combined: 0 + +3) :: + + // TX queues must be rated starting from 0, so set bws for tx0 and tx1 for Eth0 + // and for tx2 and tx3 for Eth1. That is, rates 40 and 20 Mb/s appropriately + // for Eth0 and 30 and 10 Mb/s for Eth1. + // Real speed can differ a bit due to discreetness + // Leave last 4 tx queues as not rated + $ echo 40 > /sys/class/net/eth0/queues/tx-0/tx_maxrate + $ echo 20 > /sys/class/net/eth0/queues/tx-1/tx_maxrate + $ echo 30 > /sys/class/net/eth1/queues/tx-2/tx_maxrate + $ echo 10 > /sys/class/net/eth1/queues/tx-3/tx_maxrate + +4) :: + + // Check maximum rate of tx (cpdma) queues: + $ cat /sys/class/net/eth0/queues/tx-*/tx_maxrate + 40 + 20 + 30 + 10 + 0 + 0 + 0 + 0 + +5) :: + + // Map skb->priority to traffic class for Eth0: + // 3pri -> tc0, 2pri -> tc1, (0,1,4-7)pri -> tc2 + // Map traffic class to transmit queue: + // tc0 -> txq0, tc1 -> txq1, tc2 -> (txq4, txq5) + $ tc qdisc replace dev eth0 handle 100: parent root mqprio num_tc 3 \ + map 2 2 1 0 2 2 2 2 2 2 2 2 2 2 2 2 queues 1@0 1@1 2@4 hw 1 + +6) :: + + // Check classes settings + $ tc -g class show dev eth0 + +---(100:ffe2) mqprio + | +---(100:5) mqprio + | +---(100:6) mqprio + | + +---(100:ffe1) mqprio + | +---(100:2) mqprio + | + +---(100:ffe0) mqprio + +---(100:1) mqprio + +7) :: + + // Set rate for class A - 41 Mbit (tc0, txq0) using CBS Qdisc for Eth0 + // here only idle slope is important, others ignored + // Real speed can differ a bit due to discreetness + $ tc qdisc add dev eth0 parent 100:1 cbs locredit -1470 \ + hicredit 62 sendslope -959000 idleslope 41000 offload 1 + net eth0: set FIFO3 bw = 50 + +8) :: + + // Set rate for class B - 21 Mbit (tc1, txq1) using CBS Qdisc for Eth0 + $ tc qdisc add dev eth0 parent 100:2 cbs locredit -1470 \ + hicredit 65 sendslope -979000 idleslope 21000 offload 1 + net eth0: set FIFO2 bw = 30 + +9) :: + + // Create vlan 100 to map sk->priority to vlan qos for Eth0 + $ ip link add link eth0 name eth0.100 type vlan id 100 + net eth0: Adding vlanid 100 to vlan filter + +10) :: + + // Map skb->priority to L2 prio for Eth0.100, one to one + $ ip link set eth0.100 type vlan \ + egress 0:0 1:1 2:2 3:3 4:4 5:5 6:6 7:7 + +11) :: + + // Check egress map for vlan 100 + $ cat /proc/net/vlan/eth0.100 + [...] + INGRESS priority mappings: 0:0 1:0 2:0 3:0 4:0 5:0 6:0 7:0 + EGRESS priority mappings: 0:0 1:1 2:2 3:3 4:4 5:5 6:6 7:7 + +12) :: + + // Map skb->priority to traffic class for Eth1: + // 3pri -> tc0, 2pri -> tc1, (0,1,4-7)pri -> tc2 + // Map traffic class to transmit queue: + // tc0 -> txq2, tc1 -> txq3, tc2 -> (txq6, txq7) + $ tc qdisc replace dev eth1 handle 100: parent root mqprio num_tc 3 \ + map 2 2 1 0 2 2 2 2 2 2 2 2 2 2 2 2 queues 1@2 1@3 2@6 hw 1 + +13) :: + + // Check classes settings + $ tc -g class show dev eth1 + +---(100:ffe2) mqprio + | +---(100:7) mqprio + | +---(100:8) mqprio + | + +---(100:ffe1) mqprio + | +---(100:4) mqprio + | + +---(100:ffe0) mqprio + +---(100:3) mqprio + +14) :: + + // Set rate for class A - 31 Mbit (tc0, txq2) using CBS Qdisc for Eth1 + // here only idle slope is important, others ignored, but calculated + // for interface speed - 100Mb for eth1 port. + // Set it +1 Mb for reserve (important!) + $ tc qdisc add dev eth1 parent 100:3 cbs locredit -1035 \ + hicredit 465 sendslope -69000 idleslope 31000 offload 1 + net eth1: set FIFO3 bw = 31 + +15) :: + + // Set rate for class B - 11 Mbit (tc1, txq3) using CBS Qdisc for Eth1 + // Set it +1 Mb for reserve (important!) + $ tc qdisc add dev eth1 parent 100:4 cbs locredit -1335 \ + hicredit 405 sendslope -89000 idleslope 11000 offload 1 + net eth1: set FIFO2 bw = 11 + +16) :: + + // Create vlan 100 to map sk->priority to vlan qos for Eth1 + $ ip link add link eth1 name eth1.100 type vlan id 100 + net eth1: Adding vlanid 100 to vlan filter + +17) :: + + // Map skb->priority to L2 prio for Eth1.100, one to one + $ ip link set eth1.100 type vlan \ + egress 0:0 1:1 2:2 3:3 4:4 5:5 6:6 7:7 + +18) :: + + // Check egress map for vlan 100 + $ cat /proc/net/vlan/eth1.100 + [...] + INGRESS priority mappings: 0:0 1:0 2:0 3:0 4:0 5:0 6:0 7:0 + EGRESS priority mappings: 0:0 1:1 2:2 3:3 4:4 5:5 6:6 7:7 + +19) :: + + // Run appropriate tools with socket option "SO_PRIORITY" to 3 + // for class A and to 2 for class B. For both interfaces + ./tsn_talker -d 18:03:73:66:87:42 -i eth0.100 -p2 -s 1500& + ./tsn_talker -d 18:03:73:66:87:42 -i eth0.100 -p3 -s 1500& + ./tsn_talker -d 20:cf:30:85:7d:fd -i eth1.100 -p2 -s 1500& + ./tsn_talker -d 20:cf:30:85:7d:fd -i eth1.100 -p3 -s 1500& + +20) :: + + // run your listener on workstation (should be in same vlan) + // (I took at https://www.spinics.net/lists/netdev/msg460869.html) + ./tsn_listener -d 18:03:73:66:87:42 -i enp5s0 -s 1500 + Receiving data rate: 39012 kbps + Receiving data rate: 39012 kbps + Receiving data rate: 39012 kbps + Receiving data rate: 39012 kbps + Receiving data rate: 39012 kbps + Receiving data rate: 39012 kbps + Receiving data rate: 39012 kbps + Receiving data rate: 39012 kbps + Receiving data rate: 39012 kbps + Receiving data rate: 39012 kbps + Receiving data rate: 39012 kbps + Receiving data rate: 39012 kbps + Receiving data rate: 39000 kbps + +21) :: + + // Restore default configuration if needed + $ ip link del eth1.100 + $ ip link del eth0.100 + $ tc qdisc del dev eth1 root + net eth1: Prev FIFO2 is shaped + net eth1: set FIFO3 bw = 0 + net eth1: set FIFO2 bw = 0 + $ tc qdisc del dev eth0 root + net eth0: Prev FIFO2 is shaped + net eth0: set FIFO3 bw = 0 + net eth0: set FIFO2 bw = 0 + $ ethtool -L eth0 rx 1 tx 1 diff --git a/Documentation/networking/device_drivers/ethernet/ti/cpsw_switchdev.rst b/Documentation/networking/device_drivers/ethernet/ti/cpsw_switchdev.rst new file mode 100644 index 0000000000..464dce938e --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/ti/cpsw_switchdev.rst @@ -0,0 +1,242 @@ +.. SPDX-License-Identifier: GPL-2.0 + +====================================================== +Texas Instruments CPSW switchdev based ethernet driver +====================================================== + +:Version: 2.0 + +Port renaming +============= + +On older udev versions renaming of ethX to swXpY will not be automatically +supported + +In order to rename via udev:: + + ip -d link show dev sw0p1 | grep switchid + + SUBSYSTEM=="net", ACTION=="add", ATTR{phys_switch_id}==<switchid>, \ + ATTR{phys_port_name}!="", NAME="sw0$attr{phys_port_name}" + + +Dual mac mode +============= + +- The new (cpsw_new.c) driver is operating in dual-emac mode by default, thus + working as 2 individual network interfaces. Main differences from legacy CPSW + driver are: + + - optimized promiscuous mode: The P0_UNI_FLOOD (both ports) is enabled in + addition to ALLMULTI (current port) instead of ALE_BYPASS. + So, Ports in promiscuous mode will keep possibility of mcast and vlan + filtering, which is provides significant benefits when ports are joined + to the same bridge, but without enabling "switch" mode, or to different + bridges. + - learning disabled on ports as it make not too much sense for + segregated ports - no forwarding in HW. + - enabled basic support for devlink. + + :: + + devlink dev show + platform/48484000.switch + + devlink dev param show + platform/48484000.switch: + name switch_mode type driver-specific + values: + cmode runtime value false + name ale_bypass type driver-specific + values: + cmode runtime value false + +Devlink configuration parameters +================================ + +See Documentation/networking/devlink/ti-cpsw-switch.rst + +Bridging in dual mac mode +========================= + +The dual_mac mode requires two vids to be reserved for internal purposes, +which, by default, equal CPSW Port numbers. As result, bridge has to be +configured in vlan unaware mode or default_pvid has to be adjusted:: + + ip link add name br0 type bridge + ip link set dev br0 type bridge vlan_filtering 0 + echo 0 > /sys/class/net/br0/bridge/default_pvid + ip link set dev sw0p1 master br0 + ip link set dev sw0p2 master br0 + +or:: + + ip link add name br0 type bridge + ip link set dev br0 type bridge vlan_filtering 0 + echo 100 > /sys/class/net/br0/bridge/default_pvid + ip link set dev br0 type bridge vlan_filtering 1 + ip link set dev sw0p1 master br0 + ip link set dev sw0p2 master br0 + +Enabling "switch" +================= + +The Switch mode can be enabled by configuring devlink driver parameter +"switch_mode" to 1/true:: + + devlink dev param set platform/48484000.switch \ + name switch_mode value 1 cmode runtime + +This can be done regardless of the state of Port's netdev devices - UP/DOWN, but +Port's netdev devices have to be in UP before joining to the bridge to avoid +overwriting of bridge configuration as CPSW switch driver copletly reloads its +configuration when first Port changes its state to UP. + +When the both interfaces joined the bridge - CPSW switch driver will enable +marking packets with offload_fwd_mark flag unless "ale_bypass=0" + +All configuration is implemented via switchdev API. + +Bridge setup +============ + +:: + + devlink dev param set platform/48484000.switch \ + name switch_mode value 1 cmode runtime + + ip link add name br0 type bridge + ip link set dev br0 type bridge ageing_time 1000 + ip link set dev sw0p1 up + ip link set dev sw0p2 up + ip link set dev sw0p1 master br0 + ip link set dev sw0p2 master br0 + + [*] bridge vlan add dev br0 vid 1 pvid untagged self + + [*] if vlan_filtering=1. where default_pvid=1 + + Note. Steps [*] are mandatory. + + +On/off STP +========== + +:: + + ip link set dev BRDEV type bridge stp_state 1/0 + +VLAN configuration +================== + +:: + + bridge vlan add dev br0 vid 1 pvid untagged self <---- add cpu port to VLAN 1 + +Note. This step is mandatory for bridge/default_pvid. + +Add extra VLANs +=============== + + 1. untagged:: + + bridge vlan add dev sw0p1 vid 100 pvid untagged master + bridge vlan add dev sw0p2 vid 100 pvid untagged master + bridge vlan add dev br0 vid 100 pvid untagged self <---- Add cpu port to VLAN100 + + 2. tagged:: + + bridge vlan add dev sw0p1 vid 100 master + bridge vlan add dev sw0p2 vid 100 master + bridge vlan add dev br0 vid 100 pvid tagged self <---- Add cpu port to VLAN100 + +FDBs +---- + +FDBs are automatically added on the appropriate switch port upon detection + +Manually adding FDBs:: + + bridge fdb add aa:bb:cc:dd:ee:ff dev sw0p1 master vlan 100 + bridge fdb add aa:bb:cc:dd:ee:fe dev sw0p2 master <---- Add on all VLANs + +MDBs +---- + +MDBs are automatically added on the appropriate switch port upon detection + +Manually adding MDBs:: + + bridge mdb add dev br0 port sw0p1 grp 239.1.1.1 permanent vid 100 + bridge mdb add dev br0 port sw0p1 grp 239.1.1.1 permanent <---- Add on all VLANs + +Multicast flooding +================== +CPU port mcast_flooding is always on + +Turning flooding on/off on switch ports: +bridge link set dev sw0p1 mcast_flood on/off + +Access and Trunk port +===================== + +:: + + bridge vlan add dev sw0p1 vid 100 pvid untagged master + bridge vlan add dev sw0p2 vid 100 master + + + bridge vlan add dev br0 vid 100 self + ip link add link br0 name br0.100 type vlan id 100 + +Note. Setting PVID on Bridge device itself working only for +default VLAN (default_pvid). + +NFS +=== + +The only way for NFS to work is by chrooting to a minimal environment when +switch configuration that will affect connectivity is needed. +Assuming you are booting NFS with eth1 interface(the script is hacky and +it's just there to prove NFS is doable). + +setup.sh:: + + #!/bin/sh + mkdir proc + mount -t proc none /proc + ifconfig br0 > /dev/null + if [ $? -ne 0 ]; then + echo "Setting up bridge" + ip link add name br0 type bridge + ip link set dev br0 type bridge ageing_time 1000 + ip link set dev br0 type bridge vlan_filtering 1 + + ip link set eth1 down + ip link set eth1 name sw0p1 + ip link set dev sw0p1 up + ip link set dev sw0p2 up + ip link set dev sw0p2 master br0 + ip link set dev sw0p1 master br0 + bridge vlan add dev br0 vid 1 pvid untagged self + ifconfig sw0p1 0.0.0.0 + udhchc -i br0 + fi + umount /proc + +run_nfs.sh::: + + #!/bin/sh + mkdir /tmp/root/bin -p + mkdir /tmp/root/lib -p + + cp -r /lib/ /tmp/root/ + cp -r /bin/ /tmp/root/ + cp /sbin/ip /tmp/root/bin + cp /sbin/bridge /tmp/root/bin + cp /sbin/ifconfig /tmp/root/bin + cp /sbin/udhcpc /tmp/root/bin + cp /path/to/setup.sh /tmp/root/bin + chroot /tmp/root/ busybox sh /bin/setup.sh + + run ./run_nfs.sh diff --git a/Documentation/networking/device_drivers/ethernet/ti/tlan.rst b/Documentation/networking/device_drivers/ethernet/ti/tlan.rst new file mode 100644 index 0000000000..4fdc0907f4 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/ti/tlan.rst @@ -0,0 +1,140 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================== +TLAN driver for Linux +===================== + +:Version: 1.14a + +(C) 1997-1998 Caldera, Inc. + +(C) 1998 James Banks + +(C) 1999-2001 Torben Mathiasen <tmm@image.dk, torben.mathiasen@compaq.com> + +For driver information/updates visit http://www.compaq.com + + + + + +I. Supported Devices +==================== + + Only PCI devices will work with this driver. + + Supported: + + ========= ========= =========================================== + Vendor ID Device ID Name + ========= ========= =========================================== + 0e11 ae32 Compaq Netelligent 10/100 TX PCI UTP + 0e11 ae34 Compaq Netelligent 10 T PCI UTP + 0e11 ae35 Compaq Integrated NetFlex 3/P + 0e11 ae40 Compaq Netelligent Dual 10/100 TX PCI UTP + 0e11 ae43 Compaq Netelligent Integrated 10/100 TX UTP + 0e11 b011 Compaq Netelligent 10/100 TX Embedded UTP + 0e11 b012 Compaq Netelligent 10 T/2 PCI UTP/Coax + 0e11 b030 Compaq Netelligent 10/100 TX UTP + 0e11 f130 Compaq NetFlex 3/P + 0e11 f150 Compaq NetFlex 3/P + 108d 0012 Olicom OC-2325 + 108d 0013 Olicom OC-2183 + 108d 0014 Olicom OC-2326 + ========= ========= =========================================== + + + Caveats: + + I am not sure if 100BaseTX daughterboards (for those cards which + support such things) will work. I haven't had any solid evidence + either way. + + However, if a card supports 100BaseTx without requiring an add + on daughterboard, it should work with 100BaseTx. + + The "Netelligent 10 T/2 PCI UTP/Coax" (b012) device is untested, + but I do not expect any problems. + + +II. Driver Options +================== + + 1. You can append debug=x to the end of the insmod line to get + debug messages, where x is a bit field where the bits mean + the following: + + ==== ===================================== + 0x01 Turn on general debugging messages. + 0x02 Turn on receive debugging messages. + 0x04 Turn on transmit debugging messages. + 0x08 Turn on list debugging messages. + ==== ===================================== + + 2. You can append aui=1 to the end of the insmod line to cause + the adapter to use the AUI interface instead of the 10 Base T + interface. This is also what to do if you want to use the BNC + connector on a TLAN based device. (Setting this option on a + device that does not have an AUI/BNC connector will probably + cause it to not function correctly.) + + 3. You can set duplex=1 to force half duplex, and duplex=2 to + force full duplex. + + 4. You can set speed=10 to force 10Mbs operation, and speed=100 + to force 100Mbs operation. (I'm not sure what will happen + if a card which only supports 10Mbs is forced into 100Mbs + mode.) + + 5. You have to use speed=X duplex=Y together now. If you just + do "insmod tlan.o speed=100" the driver will do Auto-Neg. + To force a 10Mbps Half-Duplex link do "insmod tlan.o speed=10 + duplex=1". + + 6. If the driver is built into the kernel, you can use the 3rd + and 4th parameters to set aui and debug respectively. For + example:: + + ether=0,0,0x1,0x7,eth0 + + This sets aui to 0x1 and debug to 0x7, assuming eth0 is a + supported TLAN device. + + The bits in the third byte are assigned as follows: + + ==== =============== + 0x01 aui + 0x02 use half duplex + 0x04 use full duplex + 0x08 use 10BaseT + 0x10 use 100BaseTx + ==== =============== + + You also need to set both speed and duplex settings when forcing + speeds with kernel-parameters. + ether=0,0,0x12,0,eth0 will force link to 100Mbps Half-Duplex. + + 7. If you have more than one tlan adapter in your system, you can + use the above options on a per adapter basis. To force a 100Mbit/HD + link with your eth1 adapter use:: + + insmod tlan speed=0,100 duplex=0,1 + + Now eth0 will use auto-neg and eth1 will be forced to 100Mbit/HD. + Note that the tlan driver supports a maximum of 8 adapters. + + +III. Things to try if you have problems +======================================= + + 1. Make sure your card's PCI id is among those listed in + section I, above. + 2. Make sure routing is correct. + 3. Try forcing different speed/duplex settings + + +There is also a tlan mailing list which you can join by sending "subscribe tlan" +in the body of an email to majordomo@vuser.vu.union.edu. + +There is also a tlan website at http://www.compaq.com + diff --git a/Documentation/networking/device_drivers/ethernet/toshiba/spider_net.rst b/Documentation/networking/device_drivers/ethernet/toshiba/spider_net.rst new file mode 100644 index 0000000000..fe5b32be15 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/toshiba/spider_net.rst @@ -0,0 +1,202 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=========================== +The Spidernet Device Driver +=========================== + +Written by Linas Vepstas <linas@austin.ibm.com> + +Version of 7 June 2007 + +Abstract +======== +This document sketches the structure of portions of the spidernet +device driver in the Linux kernel tree. The spidernet is a gigabit +ethernet device built into the Toshiba southbridge commonly used +in the SONY Playstation 3 and the IBM QS20 Cell blade. + +The Structure of the RX Ring. +============================= +The receive (RX) ring is a circular linked list of RX descriptors, +together with three pointers into the ring that are used to manage its +contents. + +The elements of the ring are called "descriptors" or "descrs"; they +describe the received data. This includes a pointer to a buffer +containing the received data, the buffer size, and various status bits. + +There are three primary states that a descriptor can be in: "empty", +"full" and "not-in-use". An "empty" or "ready" descriptor is ready +to receive data from the hardware. A "full" descriptor has data in it, +and is waiting to be emptied and processed by the OS. A "not-in-use" +descriptor is neither empty or full; it is simply not ready. It may +not even have a data buffer in it, or is otherwise unusable. + +During normal operation, on device startup, the OS (specifically, the +spidernet device driver) allocates a set of RX descriptors and RX +buffers. These are all marked "empty", ready to receive data. This +ring is handed off to the hardware, which sequentially fills in the +buffers, and marks them "full". The OS follows up, taking the full +buffers, processing them, and re-marking them empty. + +This filling and emptying is managed by three pointers, the "head" +and "tail" pointers, managed by the OS, and a hardware current +descriptor pointer (GDACTDPA). The GDACTDPA points at the descr +currently being filled. When this descr is filled, the hardware +marks it full, and advances the GDACTDPA by one. Thus, when there is +flowing RX traffic, every descr behind it should be marked "full", +and everything in front of it should be "empty". If the hardware +discovers that the current descr is not empty, it will signal an +interrupt, and halt processing. + +The tail pointer tails or trails the hardware pointer. When the +hardware is ahead, the tail pointer will be pointing at a "full" +descr. The OS will process this descr, and then mark it "not-in-use", +and advance the tail pointer. Thus, when there is flowing RX traffic, +all of the descrs in front of the tail pointer should be "full", and +all of those behind it should be "not-in-use". When RX traffic is not +flowing, then the tail pointer can catch up to the hardware pointer. +The OS will then note that the current tail is "empty", and halt +processing. + +The head pointer (somewhat mis-named) follows after the tail pointer. +When traffic is flowing, then the head pointer will be pointing at +a "not-in-use" descr. The OS will perform various housekeeping duties +on this descr. This includes allocating a new data buffer and +dma-mapping it so as to make it visible to the hardware. The OS will +then mark the descr as "empty", ready to receive data. Thus, when there +is flowing RX traffic, everything in front of the head pointer should +be "not-in-use", and everything behind it should be "empty". If no +RX traffic is flowing, then the head pointer can catch up to the tail +pointer, at which point the OS will notice that the head descr is +"empty", and it will halt processing. + +Thus, in an idle system, the GDACTDPA, tail and head pointers will +all be pointing at the same descr, which should be "empty". All of the +other descrs in the ring should be "empty" as well. + +The show_rx_chain() routine will print out the locations of the +GDACTDPA, tail and head pointers. It will also summarize the contents +of the ring, starting at the tail pointer, and listing the status +of the descrs that follow. + +A typical example of the output, for a nearly idle system, might be:: + + net eth1: Total number of descrs=256 + net eth1: Chain tail located at descr=20 + net eth1: Chain head is at 20 + net eth1: HW curr desc (GDACTDPA) is at 21 + net eth1: Have 1 descrs with stat=x40800101 + net eth1: HW next desc (GDACNEXTDA) is at 22 + net eth1: Last 255 descrs with stat=xa0800000 + +In the above, the hardware has filled in one descr, number 20. Both +head and tail are pointing at 20, because it has not yet been emptied. +Meanwhile, hw is pointing at 21, which is free. + +The "Have nnn decrs" refers to the descr starting at the tail: in this +case, nnn=1 descr, starting at descr 20. The "Last nnn descrs" refers +to all of the rest of the descrs, from the last status change. The "nnn" +is a count of how many descrs have exactly the same status. + +The status x4... corresponds to "full" and status xa... corresponds +to "empty". The actual value printed is RXCOMST_A. + +In the device driver source code, a different set of names are +used for these same concepts, so that:: + + "empty" == SPIDER_NET_DESCR_CARDOWNED == 0xa + "full" == SPIDER_NET_DESCR_FRAME_END == 0x4 + "not in use" == SPIDER_NET_DESCR_NOT_IN_USE == 0xf + + +The RX RAM full bug/feature +=========================== + +As long as the OS can empty out the RX buffers at a rate faster than +the hardware can fill them, there is no problem. If, for some reason, +the OS fails to empty the RX ring fast enough, the hardware GDACTDPA +pointer will catch up to the head, notice the not-empty condition, +ad stop. However, RX packets may still continue arriving on the wire. +The spidernet chip can save some limited number of these in local RAM. +When this local ram fills up, the spider chip will issue an interrupt +indicating this (GHIINT0STS will show ERRINT, and the GRMFLLINT bit +will be set in GHIINT1STS). When the RX ram full condition occurs, +a certain bug/feature is triggered that has to be specially handled. +This section describes the special handling for this condition. + +When the OS finally has a chance to run, it will empty out the RX ring. +In particular, it will clear the descriptor on which the hardware had +stopped. However, once the hardware has decided that a certain +descriptor is invalid, it will not restart at that descriptor; instead +it will restart at the next descr. This potentially will lead to a +deadlock condition, as the tail pointer will be pointing at this descr, +which, from the OS point of view, is empty; the OS will be waiting for +this descr to be filled. However, the hardware has skipped this descr, +and is filling the next descrs. Since the OS doesn't see this, there +is a potential deadlock, with the OS waiting for one descr to fill, +while the hardware is waiting for a different set of descrs to become +empty. + +A call to show_rx_chain() at this point indicates the nature of the +problem. A typical print when the network is hung shows the following:: + + net eth1: Spider RX RAM full, incoming packets might be discarded! + net eth1: Total number of descrs=256 + net eth1: Chain tail located at descr=255 + net eth1: Chain head is at 255 + net eth1: HW curr desc (GDACTDPA) is at 0 + net eth1: Have 1 descrs with stat=xa0800000 + net eth1: HW next desc (GDACNEXTDA) is at 1 + net eth1: Have 127 descrs with stat=x40800101 + net eth1: Have 1 descrs with stat=x40800001 + net eth1: Have 126 descrs with stat=x40800101 + net eth1: Last 1 descrs with stat=xa0800000 + +Both the tail and head pointers are pointing at descr 255, which is +marked xa... which is "empty". Thus, from the OS point of view, there +is nothing to be done. In particular, there is the implicit assumption +that everything in front of the "empty" descr must surely also be empty, +as explained in the last section. The OS is waiting for descr 255 to +become non-empty, which, in this case, will never happen. + +The HW pointer is at descr 0. This descr is marked 0x4.. or "full". +Since its already full, the hardware can do nothing more, and thus has +halted processing. Notice that descrs 0 through 254 are all marked +"full", while descr 254 and 255 are empty. (The "Last 1 descrs" is +descr 254, since tail was at 255.) Thus, the system is deadlocked, +and there can be no forward progress; the OS thinks there's nothing +to do, and the hardware has nowhere to put incoming data. + +This bug/feature is worked around with the spider_net_resync_head_ptr() +routine. When the driver receives RX interrupts, but an examination +of the RX chain seems to show it is empty, then it is probable that +the hardware has skipped a descr or two (sometimes dozens under heavy +network conditions). The spider_net_resync_head_ptr() subroutine will +search the ring for the next full descr, and the driver will resume +operations there. Since this will leave "holes" in the ring, there +is also a spider_net_resync_tail_ptr() that will skip over such holes. + +As of this writing, the spider_net_resync() strategy seems to work very +well, even under heavy network loads. + + +The TX ring +=========== +The TX ring uses a low-watermark interrupt scheme to make sure that +the TX queue is appropriately serviced for large packet sizes. + +For packet sizes greater than about 1KBytes, the kernel can fill +the TX ring quicker than the device can drain it. Once the ring +is full, the netdev is stopped. When there is room in the ring, +the netdev needs to be reawakened, so that more TX packets are placed +in the ring. The hardware can empty the ring about four times per jiffy, +so its not appropriate to wait for the poll routine to refill, since +the poll routine runs only once per jiffy. The low-watermark mechanism +marks a descr about 1/4th of the way from the bottom of the queue, so +that an interrupt is generated when the descr is processed. This +interrupt wakes up the netdev, which can then refill the queue. +For large packets, this mechanism generates a relatively small number +of interrupts, about 1K/sec. For smaller packets, this will drop to zero +interrupts, as the hardware can empty the queue faster than the kernel +can fill it. diff --git a/Documentation/networking/device_drivers/ethernet/wangxun/ngbe.rst b/Documentation/networking/device_drivers/ethernet/wangxun/ngbe.rst new file mode 100644 index 0000000000..43a02f9943 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/wangxun/ngbe.rst @@ -0,0 +1,14 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================================================= +Linux Base Driver for WangXun(R) Gigabit PCI Express Adapters +============================================================= + +WangXun Gigabit Linux driver. +Copyright (c) 2019 - 2022 Beijing WangXun Technology Co., Ltd. + +Support +======= + If you have problems with the software or hardware, please contact our + customer support team via email at nic-support@net-swift.com or check our website + at https://www.net-swift.com diff --git a/Documentation/networking/device_drivers/ethernet/wangxun/txgbe.rst b/Documentation/networking/device_drivers/ethernet/wangxun/txgbe.rst new file mode 100644 index 0000000000..d052ef40fe --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/wangxun/txgbe.rst @@ -0,0 +1,20 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================================================================ +Linux Base Driver for WangXun(R) 10 Gigabit PCI Express Adapters +================================================================ + +WangXun 10 Gigabit Linux driver. +Copyright (c) 2015 - 2022 Beijing WangXun Technology Co., Ltd. + + +Contents +======== + +- Support + + +Support +======= +If you got any problem, contact Wangxun support team via nic-support@net-swift.com +and Cc: netdev. diff --git a/Documentation/networking/device_drivers/fddi/defza.rst b/Documentation/networking/device_drivers/fddi/defza.rst new file mode 100644 index 0000000000..7393f33ea7 --- /dev/null +++ b/Documentation/networking/device_drivers/fddi/defza.rst @@ -0,0 +1,63 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================================================== +Notes on the DEC FDDIcontroller 700 (DEFZA-xx) driver +===================================================== + +:Version: v.1.1.4 + + +DEC FDDIcontroller 700 is DEC's first-generation TURBOchannel FDDI +network card, designed in 1990 specifically for the DECstation 5000 +model 200 workstation. The board is a single attachment station and +it was manufactured in two variations, both of which are supported. + +First is the SAS MMF DEFZA-AA option, the original design implementing +the standard MMF-PMD, however with a pair of ST connectors rather than +the usual MIC connector. The other one is the SAS ThinWire/STP DEFZA-CA +option, denoted 700-C, with the network medium selectable by a switch +between the DEC proprietary ThinWire-PMD using a BNC connector and the +standard STP-PMD using a DE-9F connector. This option can interface to +a DECconcentrator 500 device and, in the case of the STP-PMD, also other +FDDI equipment and was designed to make it easier to transition from +existing IEEE 802.3 10BASE2 Ethernet and IEEE 802.5 Token Ring networks +by providing means to reuse existing cabling. + +This driver handles any number of cards installed in a single system. +They get fddi0, fddi1, etc. interface names assigned in the order of +increasing TURBOchannel slot numbers. + +The board only supports DMA on the receive side. Transmission involves +the use of PIO. As a result under a heavy transmission load there will +be a significant impact on system performance. + +The board supports a 64-entry CAM for matching destination addresses. +Two entries are preoccupied by the Directed Beacon and Ring Purger +multicast addresses and the rest is used as a multicast filter. An +all-multi mode is also supported for LLC frames and it is used if +requested explicitly or if the CAM overflows. The promiscuous mode +supports separate enables for LLC and SMT frames, but this driver +doesn't support changing them individually. + + +Known problems: + +None. + + +To do: + +5. MAC address change. The card does not support changing the Media + Access Controller's address registers but a similar effect can be + achieved by adding an alias to the CAM. There is no way to disable + matching against the original address though. + +7. Queueing incoming/outgoing SMT frames in the driver if the SMT + receive/RMC transmit ring is full. (?) + +8. Retrieving/reporting FDDI/SNMP stats. + + +Both success and failure reports are welcome. + +Maciej W. Rozycki <macro@orcam.me.uk> diff --git a/Documentation/networking/device_drivers/fddi/index.rst b/Documentation/networking/device_drivers/fddi/index.rst new file mode 100644 index 0000000000..0b75294e6c --- /dev/null +++ b/Documentation/networking/device_drivers/fddi/index.rst @@ -0,0 +1,19 @@ +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) + +Fiber Distributed Data Interface (FDDI) Device Drivers +====================================================== + +Contents: + +.. toctree:: + :maxdepth: 2 + + defza + skfp + +.. only:: subproject and html + + Indices + ======= + + * :ref:`genindex` diff --git a/Documentation/networking/device_drivers/fddi/skfp.rst b/Documentation/networking/device_drivers/fddi/skfp.rst new file mode 100644 index 0000000000..58f548105c --- /dev/null +++ b/Documentation/networking/device_drivers/fddi/skfp.rst @@ -0,0 +1,253 @@ +.. SPDX-License-Identifier: GPL-2.0 + +.. include:: <isonum.txt> + +======================== +SysKonnect driver - SKFP +======================== + +|copy| Copyright 1998-2000 SysKonnect, + +skfp.txt created 11-May-2000 + +Readme File for skfp.o v2.06 + + +.. This file contains + + (1) OVERVIEW + (2) SUPPORTED ADAPTERS + (3) GENERAL INFORMATION + (4) INSTALLATION + (5) INCLUSION OF THE ADAPTER IN SYSTEM START + (6) TROUBLESHOOTING + (7) FUNCTION OF THE ADAPTER LEDS + (8) HISTORY + + +1. Overview +=========== + +This README explains how to use the driver 'skfp' for Linux with your +network adapter. + +Chapter 2: Contains a list of all network adapters that are supported by +this driver. + +Chapter 3: + Gives some general information. + +Chapter 4: Describes common problems and solutions. + +Chapter 5: Shows the changed functionality of the adapter LEDs. + +Chapter 6: History of development. + + +2. Supported adapters +===================== + +The network driver 'skfp' supports the following network adapters: +SysKonnect adapters: + + - SK-5521 (SK-NET FDDI-UP) + - SK-5522 (SK-NET FDDI-UP DAS) + - SK-5541 (SK-NET FDDI-FP) + - SK-5543 (SK-NET FDDI-LP) + - SK-5544 (SK-NET FDDI-LP DAS) + - SK-5821 (SK-NET FDDI-UP64) + - SK-5822 (SK-NET FDDI-UP64 DAS) + - SK-5841 (SK-NET FDDI-FP64) + - SK-5843 (SK-NET FDDI-LP64) + - SK-5844 (SK-NET FDDI-LP64 DAS) + +Compaq adapters (not tested): + + - Netelligent 100 FDDI DAS Fibre SC + - Netelligent 100 FDDI SAS Fibre SC + - Netelligent 100 FDDI DAS UTP + - Netelligent 100 FDDI SAS UTP + - Netelligent 100 FDDI SAS Fibre MIC + + +3. General Information +====================== + +From v2.01 on, the driver is integrated in the linux kernel sources. +Therefore, the installation is the same as for any other adapter +supported by the kernel. + +Refer to the manual of your distribution about the installation +of network adapters. + +Makes my life much easier :-) + +4. Troubleshooting +================== + +If you run into problems during installation, check those items: + +Problem: + The FDDI adapter cannot be found by the driver. + +Reason: + Look in /proc/pci for the following entry: + + 'FDDI network controller: SysKonnect SK-FDDI-PCI ...' + + If this entry exists, then the FDDI adapter has been + found by the system and should be able to be used. + + If this entry does not exist or if the file '/proc/pci' + is not there, then you may have a hardware problem or PCI + support may not be enabled in your kernel. + + The adapter can be checked using the diagnostic program + which is available from the SysKonnect web site: + + www.syskonnect.de + + Some COMPAQ machines have a problem with PCI under + Linux. This is described in the 'PCI howto' document + (included in some distributions or available from the + www, e.g. at 'www.linux.org') and no workaround is available. + +Problem: + You want to use your computer as a router between + multiple IP subnetworks (using multiple adapters), but + you cannot reach computers in other subnetworks. + +Reason: + Either the router's kernel is not configured for IP + forwarding or there is a problem with the routing table + and gateway configuration in at least one of the + computers. + +If your problem is not listed here, please contact our +technical support for help. + +You can send email to: linux@syskonnect.de + +When contacting our technical support, +please ensure that the following information is available: + +- System Manufacturer and Model +- Boards in your system +- Distribution +- Kernel version + + +5. Function of the Adapter LEDs +=============================== + + The functionality of the LED's on the FDDI network adapters was + changed in SMT version v2.82. With this new SMT version, the yellow + LED works as a ring operational indicator. An active yellow LED + indicates that the ring is down. The green LED on the adapter now + works as a link indicator where an active GREEN LED indicates that + the respective port has a physical connection. + + With versions of SMT prior to v2.82 a ring up was indicated if the + yellow LED was off while the green LED(s) showed the connection + status of the adapter. During a ring down the green LED was off and + the yellow LED was on. + + All implementations indicate that a driver is not loaded if + all LEDs are off. + + +6. History +========== + +v2.06 (20000511) (In-Kernel version) + New features: + + - 64 bit support + - new pci dma interface + - in kernel 2.3.99 + +v2.05 (20000217) (In-Kernel version) + New features: + + - Changes for 2.3.45 kernel + +v2.04 (20000207) (Standalone version) + New features: + + - Added rx/tx byte counter + +v2.03 (20000111) (Standalone version) + Problems fixed: + + - Fixed printk statements from v2.02 + +v2.02 (991215) (Standalone version) + Problems fixed: + + - Removed unnecessary output + - Fixed path for "printver.sh" in makefile + +v2.01 (991122) (In-Kernel version) + New features: + + - Integration in Linux kernel sources + - Support for memory mapped I/O. + +v2.00 (991112) + New features: + + - Full source released under GPL + +v1.05 (991023) + Problems fixed: + + - Compilation with kernel version 2.2.13 failed + +v1.04 (990427) + Changes: + + - New SMT module included, changing LED functionality + + Problems fixed: + + - Synchronization on SMP machines was buggy + +v1.03 (990325) + Problems fixed: + + - Interrupt routing on SMP machines could be incorrect + +v1.02 (990310) + New features: + + - Support for kernel versions 2.2.x added + - Kernel patch instead of private duplicate of kernel functions + +v1.01 (980812) + Problems fixed: + + Connection hangup with telnet + Slow telnet connection + +v1.00 beta 01 (980507) + New features: + + None. + + Problems fixed: + + None. + + Known limitations: + + - tar archive instead of standard package format (rpm). + - FDDI statistic is empty. + - not tested with 2.1.xx kernels + - integration in kernel not tested + - not tested simultaneously with FDDI adapters from other vendors. + - only X86 processors supported. + - SBA (Synchronous Bandwidth Allocator) parameters can + not be configured. + - does not work on some COMPAQ machines. See the PCI howto + document for details about this problem. + - data corruption with kernel versions below 2.0.33. diff --git a/Documentation/networking/device_drivers/hamradio/baycom.rst b/Documentation/networking/device_drivers/hamradio/baycom.rst new file mode 100644 index 0000000000..fe2d010f0e --- /dev/null +++ b/Documentation/networking/device_drivers/hamradio/baycom.rst @@ -0,0 +1,174 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=============================== +Linux Drivers for Baycom Modems +=============================== + +Thomas M. Sailer, HB9JNX/AE4WA, <sailer@ife.ee.ethz.ch> + +The drivers for the baycom modems have been split into +separate drivers as they did not share any code, and the driver +and device names have changed. + +This document describes the Linux Kernel Drivers for simple Baycom style +amateur radio modems. + +The following drivers are available: +==================================== + +baycom_ser_fdx: + This driver supports the SER12 modems either full or half duplex. + Its baud rate may be changed via the ``baud`` module parameter, + therefore it supports just about every bit bang modem on a + serial port. Its devices are called bcsf0 through bcsf3. + This is the recommended driver for SER12 type modems, + however if you have a broken UART clone that does not have working + delta status bits, you may try baycom_ser_hdx. + +baycom_ser_hdx: + This is an alternative driver for SER12 type modems. + It only supports half duplex, and only 1200 baud. Its devices + are called bcsh0 through bcsh3. Use this driver only if baycom_ser_fdx + does not work with your UART. + +baycom_par: + This driver supports the par96 and picpar modems. + Its devices are called bcp0 through bcp3. + +baycom_epp: + This driver supports the EPP modem. + Its devices are called bce0 through bce3. + This driver is work-in-progress. + +The following modems are supported: + +======= ======================================================================== +ser12 This is a very simple 1200 baud AFSK modem. The modem consists only + of a modulator/demodulator chip, usually a TI TCM3105. The computer + is responsible for regenerating the receiver bit clock, as well as + for handling the HDLC protocol. The modem connects to a serial port, + hence the name. Since the serial port is not used as an async serial + port, the kernel driver for serial ports cannot be used, and this + driver only supports standard serial hardware (8250, 16450, 16550) + +par96 This is a modem for 9600 baud FSK compatible to the G3RUH standard. + The modem does all the filtering and regenerates the receiver clock. + Data is transferred from and to the PC via a shift register. + The shift register is filled with 16 bits and an interrupt is signalled. + The PC then empties the shift register in a burst. This modem connects + to the parallel port, hence the name. The modem leaves the + implementation of the HDLC protocol and the scrambler polynomial to + the PC. + +picpar This is a redesign of the par96 modem by Henning Rech, DF9IC. The modem + is protocol compatible to par96, but uses only three low power ICs + and can therefore be fed from the parallel port and does not require + an additional power supply. Furthermore, it incorporates a carrier + detect circuitry. + +EPP This is a high-speed modem adaptor that connects to an enhanced parallel + port. + + Its target audience is users working over a high speed hub (76.8kbit/s). + +eppfpga This is a redesign of the EPP adaptor. +======= ======================================================================== + +All of the above modems only support half duplex communications. However, +the driver supports the KISS (see below) fullduplex command. It then simply +starts to send as soon as there's a packet to transmit and does not care +about DCD, i.e. it starts to send even if there's someone else on the channel. +This command is required by some implementations of the DAMA channel +access protocol. + + +The Interface of the drivers +============================ + +Unlike previous drivers, these drivers are no longer character devices, +but they are now true kernel network interfaces. Installation is therefore +simple. Once installed, four interfaces named bc{sf,sh,p,e}[0-3] are available. +sethdlc from the ax25 utilities may be used to set driver states etc. +Users of userland AX.25 stacks may use the net2kiss utility (also available +in the ax25 utilities package) to convert packets of a network interface +to a KISS stream on a pseudo tty. There's also a patch available from +me for WAMPES which allows attaching a kernel network interface directly. + + +Configuring the driver +====================== + +Every time a driver is inserted into the kernel, it has to know which +modems it should access at which ports. This can be done with the setbaycom +utility. If you are only using one modem, you can also configure the +driver from the insmod command line (or by means of an option line in +``/etc/modprobe.d/*.conf``). + +Examples:: + + modprobe baycom_ser_fdx mode="ser12*" iobase=0x3f8 irq=4 + sethdlc -i bcsf0 -p mode "ser12*" io 0x3f8 irq 4 + +Both lines configure the first port to drive a ser12 modem at the first +serial port (COM1 under DOS). The * in the mode parameter instructs the driver +to use the software DCD algorithm (see below):: + + insmod baycom_par mode="picpar" iobase=0x378 + sethdlc -i bcp0 -p mode "picpar" io 0x378 + +Both lines configure the first port to drive a picpar modem at the +first parallel port (LPT1 under DOS). (Note: picpar implies +hardware DCD, par96 implies software DCD). + +The channel access parameters can be set with sethdlc -a or kissparms. +Note that both utilities interpret the values slightly differently. + + +Hardware DCD versus Software DCD +================================ + +To avoid collisions on the air, the driver must know when the channel is +busy. This is the task of the DCD circuitry/software. The driver may either +utilise a software DCD algorithm (options=1) or use a DCD signal from +the hardware (options=0). + +======= ================================================================= +ser12 if software DCD is utilised, the radio's squelch should always be + open. It is highly recommended to use the software DCD algorithm, + as it is much faster than most hardware squelch circuitry. The + disadvantage is a slightly higher load on the system. + +par96 the software DCD algorithm for this type of modem is rather poor. + The modem simply does not provide enough information to implement + a reasonable DCD algorithm in software. Therefore, if your radio + feeds the DCD input of the PAR96 modem, the use of the hardware + DCD circuitry is recommended. + +picpar the picpar modem features a builtin DCD hardware, which is highly + recommended. +======= ================================================================= + + + +Compatibility with the rest of the Linux kernel +=============================================== + +The serial driver and the baycom serial drivers compete +for the same hardware resources. Of course only one driver can access a given +interface at a time. The serial driver grabs all interfaces it can find at +startup time. Therefore the baycom drivers subsequently won't be able to +access a serial port. You might therefore find it necessary to release +a port owned by the serial driver with 'setserial /dev/ttyS# uart none', where +# is the number of the interface. The baycom drivers do not reserve any +ports at startup, unless one is specified on the 'insmod' command line. Another +method to solve the problem is to compile all drivers as modules and +leave it to kmod to load the correct driver depending on the application. + +The parallel port drivers (baycom_par, baycom_epp) now use the parport subsystem +to arbitrate the ports between different client drivers. + +vy 73s de + +Tom Sailer, sailer@ife.ee.ethz.ch + +hb9jnx @ hb9w.ampr.org diff --git a/Documentation/networking/device_drivers/hamradio/index.rst b/Documentation/networking/device_drivers/hamradio/index.rst new file mode 100644 index 0000000000..7e73173205 --- /dev/null +++ b/Documentation/networking/device_drivers/hamradio/index.rst @@ -0,0 +1,19 @@ +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) + +Amateur Radio Device Drivers +============================ + +Contents: + +.. toctree:: + :maxdepth: 2 + + baycom + z8530drv + +.. only:: subproject and html + + Indices + ======= + + * :ref:`genindex` diff --git a/Documentation/networking/device_drivers/hamradio/z8530drv.rst b/Documentation/networking/device_drivers/hamradio/z8530drv.rst new file mode 100644 index 0000000000..d2942760f1 --- /dev/null +++ b/Documentation/networking/device_drivers/hamradio/z8530drv.rst @@ -0,0 +1,686 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> + +========================================================= +SCC.C - Linux driver for Z8530 based HDLC cards for AX.25 +========================================================= + + +This is a subset of the documentation. To use this driver you MUST have the +full package from: + +Internet: + + 1. ftp://ftp.ccac.rwth-aachen.de/pub/jr/z8530drv-utils_3.0-3.tar.gz + + 2. ftp://ftp.pspt.fi/pub/ham/linux/ax25/z8530drv-utils_3.0-3.tar.gz + +Please note that the information in this document may be hopelessly outdated. +A new version of the documentation, along with links to other important +Linux Kernel AX.25 documentation and programs, is available on +http://yaina.de/jreuter + +Copyright |copy| 1993,2000 by Joerg Reuter DL1BKE <jreuter@yaina.de> + +portions Copyright |copy| 1993 Guido ten Dolle PE1NNZ + +for the complete copyright notice see >> Copying.Z8530DRV << + +1. Initialization of the driver +=============================== + +To use the driver, 3 steps must be performed: + + 1. if compiled as module: loading the module + 2. Setup of hardware, MODEM and KISS parameters with sccinit + 3. Attach each channel to the Linux kernel AX.25 with "ifconfig" + +Unlike the versions below 2.4 this driver is a real network device +driver. If you want to run xNOS instead of our fine kernel AX.25 +use a 2.x version (available from above sites) or read the +AX.25-HOWTO on how to emulate a KISS TNC on network device drivers. + + +1.1 Loading the module +====================== + +(If you're going to compile the driver as a part of the kernel image, + skip this chapter and continue with 1.2) + +Before you can use a module, you'll have to load it with:: + + insmod scc.o + +please read 'man insmod' that comes with module-init-tools. + +You should include the insmod in one of the /etc/rc.d/rc.* files, +and don't forget to insert a call of sccinit after that. It +will read your /etc/z8530drv.conf. + +1.2. /etc/z8530drv.conf +======================= + +To setup all parameters you must run /sbin/sccinit from one +of your rc.*-files. This has to be done BEFORE you can +"ifconfig" an interface. Sccinit reads the file /etc/z8530drv.conf +and sets the hardware, MODEM and KISS parameters. A sample file is +delivered with this package. Change it to your needs. + +The file itself consists of two main sections. + +1.2.1 configuration of hardware parameters +========================================== + +The hardware setup section defines the following parameters for each +Z8530:: + + chip 1 + data_a 0x300 # data port A + ctrl_a 0x304 # control port A + data_b 0x301 # data port B + ctrl_b 0x305 # control port B + irq 5 # IRQ No. 5 + pclock 4915200 # clock + board BAYCOM # hardware type + escc no # enhanced SCC chip? (8580/85180/85280) + vector 0 # latch for interrupt vector + special no # address of special function register + option 0 # option to set via sfr + + +chip + - this is just a delimiter to make sccinit a bit simpler to + program. A parameter has no effect. + +data_a + - the address of the data port A of this Z8530 (needed) +ctrl_a + - the address of the control port A (needed) +data_b + - the address of the data port B (needed) +ctrl_b + - the address of the control port B (needed) + +irq + - the used IRQ for this chip. Different chips can use different + IRQs or the same. If they share an interrupt, it needs to be + specified within one chip-definition only. + +pclock - the clock at the PCLK pin of the Z8530 (option, 4915200 is + default), measured in Hertz + +board + - the "type" of the board: + + ======================= ======== + SCC type value + ======================= ======== + PA0HZP SCC card PA0HZP + EAGLE card EAGLE + PC100 card PC100 + PRIMUS-PC (DG9BL) card PRIMUS + BayCom (U)SCC card BAYCOM + ======================= ======== + +escc + - if you want support for ESCC chips (8580, 85180, 85280), set + this to "yes" (option, defaults to "no") + +vector + - address of the vector latch (aka "intack port") for PA0HZP + cards. There can be only one vector latch for all chips! + (option, defaults to 0) + +special + - address of the special function register on several cards. + (option, defaults to 0) + +option - The value you write into that register (option, default is 0) + +You can specify up to four chips (8 channels). If this is not enough, +just change:: + + #define MAXSCC 4 + +to a higher value. + +Example for the BAYCOM USCC: +---------------------------- + +:: + + chip 1 + data_a 0x300 # data port A + ctrl_a 0x304 # control port A + data_b 0x301 # data port B + ctrl_b 0x305 # control port B + irq 5 # IRQ No. 5 (#) + board BAYCOM # hardware type (*) + # + # SCC chip 2 + # + chip 2 + data_a 0x302 + ctrl_a 0x306 + data_b 0x303 + ctrl_b 0x307 + board BAYCOM + +An example for a PA0HZP card: +----------------------------- + +:: + + chip 1 + data_a 0x153 + data_b 0x151 + ctrl_a 0x152 + ctrl_b 0x150 + irq 9 + pclock 4915200 + board PA0HZP + vector 0x168 + escc no + # + # + # + chip 2 + data_a 0x157 + data_b 0x155 + ctrl_a 0x156 + ctrl_b 0x154 + irq 9 + pclock 4915200 + board PA0HZP + vector 0x168 + escc no + +A DRSI would should probably work with this: +-------------------------------------------- +(actually: two DRSI cards...) + +:: + + chip 1 + data_a 0x303 + data_b 0x301 + ctrl_a 0x302 + ctrl_b 0x300 + irq 7 + pclock 4915200 + board DRSI + escc no + # + # + # + chip 2 + data_a 0x313 + data_b 0x311 + ctrl_a 0x312 + ctrl_b 0x310 + irq 7 + pclock 4915200 + board DRSI + escc no + +Note that you cannot use the on-board baudrate generator off DRSI +cards. Use "mode dpll" for clock source (see below). + +This is based on information provided by Mike Bilow (and verified +by Paul Helay) + +The utility "gencfg" +-------------------- + +If you only know the parameters for the PE1CHL driver for DOS, +run gencfg. It will generate the correct port addresses (I hope). +Its parameters are exactly the same as the ones you use with +the "attach scc" command in net, except that the string "init" must +not appear. Example:: + + gencfg 2 0x150 4 2 0 1 0x168 9 4915200 + +will print a skeleton z8530drv.conf for the OptoSCC to stdout. + +:: + + gencfg 2 0x300 2 4 5 -4 0 7 4915200 0x10 + +does the same for the BAYCOM USCC card. In my opinion it is much easier +to edit scc_config.h... + + +1.2.2 channel configuration +=========================== + +The channel definition is divided into three sub sections for each +channel: + +An example for scc0:: + + # DEVICE + + device scc0 # the device for the following params + + # MODEM / BUFFERS + + speed 1200 # the default baudrate + clock dpll # clock source: + # dpll = normal half duplex operation + # external = MODEM provides own Rx/Tx clock + # divider = use full duplex divider if + # installed (1) + mode nrzi # HDLC encoding mode + # nrzi = 1k2 MODEM, G3RUH 9k6 MODEM + # nrz = DF9IC 9k6 MODEM + # + bufsize 384 # size of buffers. Note that this must include + # the AX.25 header, not only the data field! + # (optional, defaults to 384) + + # KISS (Layer 1) + + txdelay 36 # (see chapter 1.4) + persist 64 + slot 8 + tail 8 + fulldup 0 + wait 12 + min 3 + maxkey 7 + idle 3 + maxdef 120 + group 0 + txoff off + softdcd on + slip off + +The order WITHIN these sections is unimportant. The order OF these +sections IS important. The MODEM parameters are set with the first +recognized KISS parameter... + +Please note that you can initialize the board only once after boot +(or insmod). You can change all parameters but "mode" and "clock" +later with the Sccparam program or through KISS. Just to avoid +security holes... + +(1) this divider is usually mounted on the SCC-PBC (PA0HZP) or not + present at all (BayCom). It feeds back the output of the DPLL + (digital pll) as transmit clock. Using this mode without a divider + installed will normally result in keying the transceiver until + maxkey expires --- of course without sending anything (useful). + +2. Attachment of a channel by your AX.25 software +================================================= + +2.1 Kernel AX.25 +================ + +To set up an AX.25 device you can simply type:: + + ifconfig scc0 44.128.1.1 hw ax25 dl0tha-7 + +This will create a network interface with the IP number 44.128.20.107 +and the callsign "dl0tha". If you do not have any IP number (yet) you +can use any of the 44.128.0.0 network. Note that you do not need +axattach. The purpose of axattach (like slattach) is to create a KISS +network device linked to a TTY. Please read the documentation of the +ax25-utils and the AX.25-HOWTO to learn how to set the parameters of +the kernel AX.25. + +2.2 NOS, NET and TFKISS +======================= + +Since the TTY driver (aka KISS TNC emulation) is gone you need +to emulate the old behaviour. The cost of using these programs is +that you probably need to compile the kernel AX.25, regardless of whether +you actually use it or not. First setup your /etc/ax25/axports, +for example:: + + 9k6 dl0tha-9 9600 255 4 9600 baud port (scc3) + axlink dl0tha-15 38400 255 4 Link to NOS + +Now "ifconfig" the scc device:: + + ifconfig scc3 44.128.1.1 hw ax25 dl0tha-9 + +You can now axattach a pseudo-TTY:: + + axattach /dev/ptys0 axlink + +and start your NOS and attach /dev/ptys0 there. The problem is that +NOS is reachable only via digipeating through the kernel AX.25 +(disastrous on a DAMA controlled channel). To solve this problem, +configure "rxecho" to echo the incoming frames from "9k6" to "axlink" +and outgoing frames from "axlink" to "9k6" and start:: + + rxecho + +Or simply use "kissbridge" coming with z8530drv-utils:: + + ifconfig scc3 hw ax25 dl0tha-9 + kissbridge scc3 /dev/ptys0 + + +3. Adjustment and Display of parameters +======================================= + +3.1 Displaying SCC Parameters: +============================== + +Once a SCC channel has been attached, the parameter settings and +some statistic information can be shown using the param program:: + + dl1bke-u:~$ sccstat scc0 + + Parameters: + + speed : 1200 baud + txdelay : 36 + persist : 255 + slottime : 0 + txtail : 8 + fulldup : 1 + waittime : 12 + mintime : 3 sec + maxkeyup : 7 sec + idletime : 3 sec + maxdefer : 120 sec + group : 0x00 + txoff : off + softdcd : on + SLIP : off + + Status: + + HDLC Z8530 Interrupts Buffers + ----------------------------------------------------------------------- + Sent : 273 RxOver : 0 RxInts : 125074 Size : 384 + Received : 1095 TxUnder: 0 TxInts : 4684 NoSpace : 0 + RxErrors : 1591 ExInts : 11776 + TxErrors : 0 SpInts : 1503 + Tx State : idle + + +The status info shown is: + +============== ============================================================== +Sent number of frames transmitted +Received number of frames received +RxErrors number of receive errors (CRC, ABORT) +TxErrors number of discarded Tx frames (due to various reasons) +Tx State status of the Tx interrupt handler: idle/busy/active/tail (2) +RxOver number of receiver overruns +TxUnder number of transmitter underruns +RxInts number of receiver interrupts +TxInts number of transmitter interrupts +EpInts number of receiver special condition interrupts +SpInts number of external/status interrupts +Size maximum size of an AX.25 frame (*with* AX.25 headers!) +NoSpace number of times a buffer could not get allocated +============== ============================================================== + +An overrun is abnormal. If lots of these occur, the product of +baudrate and number of interfaces is too high for the processing +power of your computer. NoSpace errors are unlikely to be caused by the +driver or the kernel AX.25. + + +3.2 Setting Parameters +====================== + + +The setting of parameters of the emulated KISS TNC is done in the +same way in the SCC driver. You can change parameters by using +the kissparms program from the ax25-utils package or use the program +"sccparam":: + + sccparam <device> <paramname> <decimal-|hexadecimal value> + +You can change the following parameters: + +=========== ===== +param value +=========== ===== +speed 1200 +txdelay 36 +persist 255 +slottime 0 +txtail 8 +fulldup 1 +waittime 12 +mintime 3 +maxkeyup 7 +idletime 3 +maxdefer 120 +group 0x00 +txoff off +softdcd on +SLIP off +=========== ===== + + +The parameters have the following meaning: + +speed: + The baudrate on this channel in bits/sec + + Example: sccparam /dev/scc3 speed 9600 + +txdelay: + The delay (in units of 10 ms) after keying of the + transmitter, until the first byte is sent. This is usually + called "TXDELAY" in a TNC. When 0 is specified, the driver + will just wait until the CTS signal is asserted. This + assumes the presence of a timer or other circuitry in the + MODEM and/or transmitter, that asserts CTS when the + transmitter is ready for data. + A normal value of this parameter is 30-36. + + Example: sccparam /dev/scc0 txd 20 + +persist: + This is the probability that the transmitter will be keyed + when the channel is found to be free. It is a value from 0 + to 255, and the probability is (value+1)/256. The value + should be somewhere near 50-60, and should be lowered when + the channel is used more heavily. + + Example: sccparam /dev/scc2 persist 20 + +slottime: + This is the time between samples of the channel. It is + expressed in units of 10 ms. About 200-300 ms (value 20-30) + seems to be a good value. + + Example: sccparam /dev/scc0 slot 20 + +tail: + The time the transmitter will remain keyed after the last + byte of a packet has been transferred to the SCC. This is + necessary because the CRC and a flag still have to leave the + SCC before the transmitter is keyed down. The value depends + on the baudrate selected. A few character times should be + sufficient, e.g. 40ms at 1200 baud. (value 4) + The value of this parameter is in 10 ms units. + + Example: sccparam /dev/scc2 4 + +full: + The full-duplex mode switch. This can be one of the following + values: + + 0: The interface will operate in CSMA mode (the normal + half-duplex packet radio operation) + 1: Fullduplex mode, i.e. the transmitter will be keyed at + any time, without checking the received carrier. It + will be unkeyed when there are no packets to be sent. + 2: Like 1, but the transmitter will remain keyed, also + when there are no packets to be sent. Flags will be + sent in that case, until a timeout (parameter 10) + occurs. + + Example: sccparam /dev/scc0 fulldup off + +wait: + The initial waittime before any transmit attempt, after the + frame has been queue for transmit. This is the length of + the first slot in CSMA mode. In full duplex modes it is + set to 0 for maximum performance. + The value of this parameter is in 10 ms units. + + Example: sccparam /dev/scc1 wait 4 + +maxkey: + The maximal time the transmitter will be keyed to send + packets, in seconds. This can be useful on busy CSMA + channels, to avoid "getting a bad reputation" when you are + generating a lot of traffic. After the specified time has + elapsed, no new frame will be started. Instead, the trans- + mitter will be switched off for a specified time (parameter + min), and then the selected algorithm for keyup will be + started again. + The value 0 as well as "off" will disable this feature, + and allow infinite transmission time. + + Example: sccparam /dev/scc0 maxk 20 + +min: + This is the time the transmitter will be switched off when + the maximum transmission time is exceeded. + + Example: sccparam /dev/scc3 min 10 + +idle: + This parameter specifies the maximum idle time in full duplex + 2 mode, in seconds. When no frames have been sent for this + time, the transmitter will be keyed down. A value of 0 is + has same result as the fullduplex mode 1. This parameter + can be disabled. + + Example: sccparam /dev/scc2 idle off # transmit forever + +maxdefer + This is the maximum time (in seconds) to wait for a free channel + to send. When this timer expires the transmitter will be keyed + IMMEDIATELY. If you love to get trouble with other users you + should set this to a very low value ;-) + + Example: sccparam /dev/scc0 maxdefer 240 # 2 minutes + + +txoff: + When this parameter has the value 0, the transmission of packets + is enable. Otherwise it is disabled. + + Example: sccparam /dev/scc2 txoff on + +group: + It is possible to build special radio equipment to use more than + one frequency on the same band, e.g. using several receivers and + only one transmitter that can be switched between frequencies. + Also, you can connect several radios that are active on the same + band. In these cases, it is not possible, or not a good idea, to + transmit on more than one frequency. The SCC driver provides a + method to lock transmitters on different interfaces, using the + "param <interface> group <x>" command. This will only work when + you are using CSMA mode (parameter full = 0). + + The number <x> must be 0 if you want no group restrictions, and + can be computed as follows to create restricted groups: + <x> is the sum of some OCTAL numbers: + + + === ======================================================= + 200 This transmitter will only be keyed when all other + transmitters in the group are off. + 100 This transmitter will only be keyed when the carrier + detect of all other interfaces in the group is off. + 0xx A byte that can be used to define different groups. + Interfaces are in the same group, when the logical AND + between their xx values is nonzero. + === ======================================================= + + Examples: + + When 2 interfaces use group 201, their transmitters will never be + keyed at the same time. + + When 2 interfaces use group 101, the transmitters will only key + when both channels are clear at the same time. When group 301, + the transmitters will not be keyed at the same time. + + Don't forget to convert the octal numbers into decimal before + you set the parameter. + + Example: (to be written) + +softdcd: + use a software dcd instead of the real one... Useful for a very + slow squelch. + + Example: sccparam /dev/scc0 soft on + + +4. Problems +=========== + +If you have tx-problems with your BayCom USCC card please check +the manufacturer of the 8530. SGS chips have a slightly +different timing. Try Zilog... A solution is to write to register 8 +instead to the data port, but this won't work with the ESCC chips. +*SIGH!* + +A very common problem is that the PTT locks until the maxkeyup timer +expires, although interrupts and clock source are correct. In most +cases compiling the driver with CONFIG_SCC_DELAY (set with +make config) solves the problems. For more hints read the (pseudo) FAQ +and the documentation coming with z8530drv-utils. + +I got reports that the driver has problems on some 386-based systems. +(i.e. Amstrad) Those systems have a bogus AT bus timing which will +lead to delayed answers on interrupts. You can recognize these +problems by looking at the output of Sccstat for the suspected +port. If it shows under- and overruns you own such a system. + +Delayed processing of received data: This depends on + +- the kernel version + +- kernel profiling compiled or not + +- a high interrupt load + +- a high load of the machine --- running X, Xmorph, XV and Povray, + while compiling the kernel... hmm ... even with 32 MB RAM ... ;-) + Or running a named for the whole .ampr.org domain on an 8 MB + box... + +- using information from rxecho or kissbridge. + +Kernel panics: please read /linux/README and find out if it +really occurred within the scc driver. + +If you cannot solve a problem, send me + +- a description of the problem, +- information on your hardware (computer system, scc board, modem) +- your kernel version +- the output of cat /proc/net/z8530 + +4. Thor RLC100 +============== + +Mysteriously this board seems not to work with the driver. Anyone +got it up-and-running? + + +Many thanks to Linus Torvalds and Alan Cox for including the driver +in the Linux standard distribution and their support. + +:: + + Joerg Reuter ampr-net: dl1bke@db0pra.ampr.org + AX-25 : DL1BKE @ DB0ABH.#BAY.DEU.EU + Internet: jreuter@yaina.de + WWW : http://yaina.de/jreuter diff --git a/Documentation/networking/device_drivers/index.rst b/Documentation/networking/device_drivers/index.rst new file mode 100644 index 0000000000..601eacaf12 --- /dev/null +++ b/Documentation/networking/device_drivers/index.rst @@ -0,0 +1,28 @@ +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) + +Hardware Device Drivers +======================= + +Contents: + +.. toctree:: + :maxdepth: 2 + + appletalk/index + atm/index + cable/index + can/index + cellular/index + ethernet/index + fddi/index + hamradio/index + qlogic/index + wifi/index + wwan/index + +.. only:: subproject and html + + Indices + ======= + + * :ref:`genindex` diff --git a/Documentation/networking/device_drivers/qlogic/index.rst b/Documentation/networking/device_drivers/qlogic/index.rst new file mode 100644 index 0000000000..ad05b04286 --- /dev/null +++ b/Documentation/networking/device_drivers/qlogic/index.rst @@ -0,0 +1,18 @@ +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) + +QLogic QLGE Device Drivers +=============================================== + +Contents: + +.. toctree:: + :maxdepth: 2 + + qlge + +.. only:: subproject and html + + Indices + ======= + + * :ref:`genindex` diff --git a/Documentation/networking/device_drivers/qlogic/qlge.rst b/Documentation/networking/device_drivers/qlogic/qlge.rst new file mode 100644 index 0000000000..0b888253d1 --- /dev/null +++ b/Documentation/networking/device_drivers/qlogic/qlge.rst @@ -0,0 +1,118 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======================================= +QLogic QLGE 10Gb Ethernet device driver +======================================= + +This driver use drgn and devlink for debugging. + +Dump kernel data structures in drgn +----------------------------------- + +To dump kernel data structures, the following Python script can be used +in drgn: + +.. code-block:: python + + def align(x, a): + """the alignment a should be a power of 2 + """ + mask = a - 1 + return (x+ mask) & ~mask + + def struct_size(struct_type): + struct_str = "struct {}".format(struct_type) + return sizeof(Object(prog, struct_str, address=0x0)) + + def netdev_priv(netdevice): + NETDEV_ALIGN = 32 + return netdevice.value_() + align(struct_size("net_device"), NETDEV_ALIGN) + + name = 'xxx' + qlge_device = None + netdevices = prog['init_net'].dev_base_head.address_of_() + for netdevice in list_for_each_entry("struct net_device", netdevices, "dev_list"): + if netdevice.name.string_().decode('ascii') == name: + print(netdevice.name) + + ql_adapter = Object(prog, "struct ql_adapter", address=netdev_priv(qlge_device)) + +The struct ql_adapter will be printed in drgn as follows, + + >>> ql_adapter + (struct ql_adapter){ + .ricb = (struct ricb){ + .base_cq = (u8)0, + .flags = (u8)120, + .mask = (__le16)26637, + .hash_cq_id = (u8 [1024]){ 172, 142, 255, 255 }, + .ipv6_hash_key = (__le32 [10]){}, + .ipv4_hash_key = (__le32 [4]){}, + }, + .flags = (unsigned long)0, + .wol = (u32)0, + .nic_stats = (struct nic_stats){ + .tx_pkts = (u64)0, + .tx_bytes = (u64)0, + .tx_mcast_pkts = (u64)0, + .tx_bcast_pkts = (u64)0, + .tx_ucast_pkts = (u64)0, + .tx_ctl_pkts = (u64)0, + .tx_pause_pkts = (u64)0, + ... + }, + .active_vlans = (unsigned long [64]){ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 52780853100545, 18446744073709551615, + 18446619461681283072, 0, 42949673024, 2147483647, + }, + .rx_ring = (struct rx_ring [17]){ + { + .cqicb = (struct cqicb){ + .msix_vect = (u8)0, + .reserved1 = (u8)0, + .reserved2 = (u8)0, + .flags = (u8)0, + .len = (__le16)0, + .rid = (__le16)0, + ... + }, + .cq_base = (void *)0x0, + .cq_base_dma = (dma_addr_t)0, + } + ... + } + } + +coredump via devlink +-------------------- + + +And the coredump obtained via devlink in json format looks like, + +.. code:: shell + + $ devlink health dump show DEVICE reporter coredump -p -j + { + "Core Registers": { + "segment": 1, + "values": [ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 ] + }, + "Test Logic Regs": { + "segment": 2, + "values": [ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 ] + }, + "RMII Registers": { + "segment": 3, + "values": [ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 ] + }, + ... + "Sem Registers": { + "segment": 50, + "values": [ 0,0,0,0 ] + } + } + +When the module parameter qlge_force_coredump is set to be true, the MPI +RISC reset before coredumping. So coredumping will much longer since +devlink tool has to wait for 5 secs for the resetting to be +finished. diff --git a/Documentation/networking/device_drivers/wifi/index.rst b/Documentation/networking/device_drivers/wifi/index.rst new file mode 100644 index 0000000000..bf91a87c7a --- /dev/null +++ b/Documentation/networking/device_drivers/wifi/index.rst @@ -0,0 +1,20 @@ +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) + +Wi-Fi Device Drivers +==================== + +Contents: + +.. toctree:: + :maxdepth: 2 + + intel/ipw2100 + intel/ipw2200 + ray_cs + +.. only:: subproject and html + + Indices + ======= + + * :ref:`genindex` diff --git a/Documentation/networking/device_drivers/wifi/intel/ipw2100.rst b/Documentation/networking/device_drivers/wifi/intel/ipw2100.rst new file mode 100644 index 0000000000..883e963557 --- /dev/null +++ b/Documentation/networking/device_drivers/wifi/intel/ipw2100.rst @@ -0,0 +1,323 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> + +=========================================== +Intel(R) PRO/Wireless 2100 Driver for Linux +=========================================== + +Support for: + +- Intel(R) PRO/Wireless 2100 Network Connection + +Copyright |copy| 2003-2006, Intel Corporation + +README.ipw2100 + +:Version: git-1.1.5 +:Date: January 25, 2006 + +.. Index + + 0. IMPORTANT INFORMATION BEFORE USING THIS DRIVER + 1. Introduction + 2. Release git-1.1.5 Current Features + 3. Command Line Parameters + 4. Sysfs Helper Files + 5. Radio Kill Switch + 6. Dynamic Firmware + 7. Power Management + 8. Support + 9. License + + +0. IMPORTANT INFORMATION BEFORE USING THIS DRIVER +================================================= + +Important Notice FOR ALL USERS OR DISTRIBUTORS!!!! + +Intel wireless LAN adapters are engineered, manufactured, tested, and +quality checked to ensure that they meet all necessary local and +governmental regulatory agency requirements for the regions that they +are designated and/or marked to ship into. Since wireless LANs are +generally unlicensed devices that share spectrum with radars, +satellites, and other licensed and unlicensed devices, it is sometimes +necessary to dynamically detect, avoid, and limit usage to avoid +interference with these devices. In many instances Intel is required to +provide test data to prove regional and local compliance to regional and +governmental regulations before certification or approval to use the +product is granted. Intel's wireless LAN's EEPROM, firmware, and +software driver are designed to carefully control parameters that affect +radio operation and to ensure electromagnetic compliance (EMC). These +parameters include, without limitation, RF power, spectrum usage, +channel scanning, and human exposure. + +For these reasons Intel cannot permit any manipulation by third parties +of the software provided in binary format with the wireless WLAN +adapters (e.g., the EEPROM and firmware). Furthermore, if you use any +patches, utilities, or code with the Intel wireless LAN adapters that +have been manipulated by an unauthorized party (i.e., patches, +utilities, or code (including open source code modifications) which have +not been validated by Intel), (i) you will be solely responsible for +ensuring the regulatory compliance of the products, (ii) Intel will bear +no liability, under any theory of liability for any issues associated +with the modified products, including without limitation, claims under +the warranty and/or issues arising from regulatory non-compliance, and +(iii) Intel will not provide or be required to assist in providing +support to any third parties for such modified products. + +Note: Many regulatory agencies consider Wireless LAN adapters to be +modules, and accordingly, condition system-level regulatory approval +upon receipt and review of test data documenting that the antennas and +system configuration do not cause the EMC and radio operation to be +non-compliant. + +The drivers available for download from SourceForge are provided as a +part of a development project. Conformance to local regulatory +requirements is the responsibility of the individual developer. As +such, if you are interested in deploying or shipping a driver as part of +solution intended to be used for purposes other than development, please +obtain a tested driver from Intel Customer Support at: + +https://www.intel.com/support/wireless/sb/CS-006408.htm + +1. Introduction +=============== + +This document provides a brief overview of the features supported by the +IPW2100 driver project. The main project website, where the latest +development version of the driver can be found, is: + + http://ipw2100.sourceforge.net + +There you can find the not only the latest releases, but also information about +potential fixes and patches, as well as links to the development mailing list +for the driver project. + + +2. Release git-1.1.5 Current Supported Features +=============================================== + +- Managed (BSS) and Ad-Hoc (IBSS) +- WEP (shared key and open) +- Wireless Tools support +- 802.1x (tested with XSupplicant 1.0.1) + +Enabled (but not supported) features: +- Monitor/RFMon mode +- WPA/WPA2 + +The distinction between officially supported and enabled is a reflection +on the amount of validation and interoperability testing that has been +performed on a given feature. + + +3. Command Line Parameters +========================== + +If the driver is built as a module, the following optional parameters are used +by entering them on the command line with the modprobe command using this +syntax:: + + modprobe ipw2100 [<option>=<VAL1><,VAL2>...] + +For example, to disable the radio on driver loading, enter: + + modprobe ipw2100 disable=1 + +The ipw2100 driver supports the following module parameters: + +========= ============== ============ ============================== +Name Value Example Meaning +========= ============== ============ ============================== +debug 0x0-0xffffffff debug=1024 Debug level set to 1024 +mode 0,1,2 mode=1 AdHoc +channel int channel=3 Only valid in AdHoc or Monitor +associate boolean associate=0 Do NOT auto associate +disable boolean disable=1 Do not power the HW +========= ============== ============ ============================== + + +4. Sysfs Helper Files +===================== + +There are several ways to control the behavior of the driver. Many of the +general capabilities are exposed through the Wireless Tools (iwconfig). There +are a few capabilities that are exposed through entries in the Linux Sysfs. + + +**Driver Level** + +For the driver level files, look in /sys/bus/pci/drivers/ipw2100/ + + debug_level + This controls the same global as the 'debug' module parameter. For + information on the various debugging levels available, run the 'dvals' + script found in the driver source directory. + + .. note:: + + 'debug_level' is only enabled if CONFIG_IPW2100_DEBUG is turn on. + +**Device Level** + +For the device level files look in:: + + /sys/bus/pci/drivers/ipw2100/{PCI-ID}/ + +For example:: + + /sys/bus/pci/drivers/ipw2100/0000:02:01.0 + +For the device level files, see /sys/bus/pci/drivers/ipw2100: + + rf_kill + read + + == ========================================= + 0 RF kill not enabled (radio on) + 1 SW based RF kill active (radio off) + 2 HW based RF kill active (radio off) + 3 Both HW and SW RF kill active (radio off) + == ========================================= + + write + + == ================================================== + 0 If SW based RF kill active, turn the radio back on + 1 If radio is on, activate SW based RF kill + == ================================================== + + .. note:: + + If you enable the SW based RF kill and then toggle the HW + based RF kill from ON -> OFF -> ON, the radio will NOT come back on + + +5. Radio Kill Switch +==================== + +Most laptops provide the ability for the user to physically disable the radio. +Some vendors have implemented this as a physical switch that requires no +software to turn the radio off and on. On other laptops, however, the switch +is controlled through a button being pressed and a software driver then making +calls to turn the radio off and on. This is referred to as a "software based +RF kill switch" + +See the Sysfs helper file 'rf_kill' for determining the state of the RF switch +on your system. + + +6. Dynamic Firmware +=================== + +As the firmware is licensed under a restricted use license, it can not be +included within the kernel sources. To enable the IPW2100 you will need a +firmware image to load into the wireless NIC's processors. + +You can obtain these images from <http://ipw2100.sf.net/firmware.php>. + +See INSTALL for instructions on installing the firmware. + + +7. Power Management +=================== + +The IPW2100 supports the configuration of the Power Save Protocol +through a private wireless extension interface. The IPW2100 supports +the following different modes: + + === =========================================================== + off No power management. Radio is always on. + on Automatic power management + 1-5 Different levels of power management. The higher the + number the greater the power savings, but with an impact to + packet latencies. + === =========================================================== + +Power management works by powering down the radio after a certain +interval of time has passed where no packets are passed through the +radio. Once powered down, the radio remains in that state for a given +period of time. For higher power savings, the interval between last +packet processed to sleep is shorter and the sleep period is longer. + +When the radio is asleep, the access point sending data to the station +must buffer packets at the AP until the station wakes up and requests +any buffered packets. If you have an AP that does not correctly support +the PSP protocol you may experience packet loss or very poor performance +while power management is enabled. If this is the case, you will need +to try and find a firmware update for your AP, or disable power +management (via ``iwconfig eth1 power off``) + +To configure the power level on the IPW2100 you use a combination of +iwconfig and iwpriv. iwconfig is used to turn power management on, off, +and set it to auto. + + ========================= ==================================== + iwconfig eth1 power off Disables radio power down + iwconfig eth1 power on Enables radio power management to + last set level (defaults to AUTO) + iwpriv eth1 set_power 0 Sets power level to AUTO and enables + power management if not previously + enabled. + iwpriv eth1 set_power 1-5 Set the power level as specified, + enabling power management if not + previously enabled. + ========================= ==================================== + +You can view the current power level setting via:: + + iwpriv eth1 get_power + +It will return the current period or timeout that is configured as a string +in the form of xxxx/yyyy (z) where xxxx is the timeout interval (amount of +time after packet processing), yyyy is the period to sleep (amount of time to +wait before powering the radio and querying the access point for buffered +packets), and z is the 'power level'. If power management is turned off the +xxxx/yyyy will be replaced with 'off' -- the level reported will be the active +level if `iwconfig eth1 power on` is invoked. + + +8. Support +========== + +For general development information and support, +go to: + + http://ipw2100.sf.net/ + +The ipw2100 1.1.0 driver and firmware can be downloaded from: + + http://support.intel.com + +For installation support on the ipw2100 1.1.0 driver on Linux kernels +2.6.8 or greater, email support is available from: + + http://supportmail.intel.com + +9. License +========== + + Copyright |copy| 2003 - 2006 Intel Corporation. All rights reserved. + + This program is free software; you can redistribute it and/or modify it + under the terms of the GNU General Public License (version 2) as + published by the Free Software Foundation. + + This program is distributed in the hope that it will be useful, but WITHOUT + ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + more details. + + You should have received a copy of the GNU General Public License along with + this program; if not, write to the Free Software Foundation, Inc., 59 + Temple Place - Suite 330, Boston, MA 02111-1307, USA. + + The full GNU General Public License is included in this distribution in the + file called LICENSE. + + License Contact Information: + + James P. Ketrenos <ipw2100-admin@linux.intel.com> + + Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497 + diff --git a/Documentation/networking/device_drivers/wifi/intel/ipw2200.rst b/Documentation/networking/device_drivers/wifi/intel/ipw2200.rst new file mode 100644 index 0000000000..0cb42d2fd7 --- /dev/null +++ b/Documentation/networking/device_drivers/wifi/intel/ipw2200.rst @@ -0,0 +1,526 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> + +============================================== +Intel(R) PRO/Wireless 2915ABG Driver for Linux +============================================== + + +Support for: + +- Intel(R) PRO/Wireless 2200BG Network Connection +- Intel(R) PRO/Wireless 2915ABG Network Connection + +Note: The Intel(R) PRO/Wireless 2915ABG Driver for Linux and Intel(R) +PRO/Wireless 2200BG Driver for Linux is a unified driver that works on +both hardware adapters listed above. In this document the Intel(R) +PRO/Wireless 2915ABG Driver for Linux will be used to reference the +unified driver. + +Copyright |copy| 2004-2006, Intel Corporation + +README.ipw2200 + +:Version: 1.1.2 +:Date: March 30, 2006 + + +.. Index + + 0. IMPORTANT INFORMATION BEFORE USING THIS DRIVER + 1. Introduction + 1.1. Overview of features + 1.2. Module parameters + 1.3. Wireless Extension Private Methods + 1.4. Sysfs Helper Files + 1.5. Supported channels + 2. Ad-Hoc Networking + 3. Interacting with Wireless Tools + 3.1. iwconfig mode + 3.2. iwconfig sens + 4. About the Version Numbers + 5. Firmware installation + 6. Support + 7. License + + +0. IMPORTANT INFORMATION BEFORE USING THIS DRIVER +================================================= + +Important Notice FOR ALL USERS OR DISTRIBUTORS!!!! + +Intel wireless LAN adapters are engineered, manufactured, tested, and +quality checked to ensure that they meet all necessary local and +governmental regulatory agency requirements for the regions that they +are designated and/or marked to ship into. Since wireless LANs are +generally unlicensed devices that share spectrum with radars, +satellites, and other licensed and unlicensed devices, it is sometimes +necessary to dynamically detect, avoid, and limit usage to avoid +interference with these devices. In many instances Intel is required to +provide test data to prove regional and local compliance to regional and +governmental regulations before certification or approval to use the +product is granted. Intel's wireless LAN's EEPROM, firmware, and +software driver are designed to carefully control parameters that affect +radio operation and to ensure electromagnetic compliance (EMC). These +parameters include, without limitation, RF power, spectrum usage, +channel scanning, and human exposure. + +For these reasons Intel cannot permit any manipulation by third parties +of the software provided in binary format with the wireless WLAN +adapters (e.g., the EEPROM and firmware). Furthermore, if you use any +patches, utilities, or code with the Intel wireless LAN adapters that +have been manipulated by an unauthorized party (i.e., patches, +utilities, or code (including open source code modifications) which have +not been validated by Intel), (i) you will be solely responsible for +ensuring the regulatory compliance of the products, (ii) Intel will bear +no liability, under any theory of liability for any issues associated +with the modified products, including without limitation, claims under +the warranty and/or issues arising from regulatory non-compliance, and +(iii) Intel will not provide or be required to assist in providing +support to any third parties for such modified products. + +Note: Many regulatory agencies consider Wireless LAN adapters to be +modules, and accordingly, condition system-level regulatory approval +upon receipt and review of test data documenting that the antennas and +system configuration do not cause the EMC and radio operation to be +non-compliant. + +The drivers available for download from SourceForge are provided as a +part of a development project. Conformance to local regulatory +requirements is the responsibility of the individual developer. As +such, if you are interested in deploying or shipping a driver as part of +solution intended to be used for purposes other than development, please +obtain a tested driver from Intel Customer Support at: + +http://support.intel.com + + +1. Introduction +=============== + +The following sections attempt to provide a brief introduction to using +the Intel(R) PRO/Wireless 2915ABG Driver for Linux. + +This document is not meant to be a comprehensive manual on +understanding or using wireless technologies, but should be sufficient +to get you moving without wires on Linux. + +For information on building and installing the driver, see the INSTALL +file. + + +1.1. Overview of Features +------------------------- +The current release (1.1.2) supports the following features: + ++ BSS mode (Infrastructure, Managed) ++ IBSS mode (Ad-Hoc) ++ WEP (OPEN and SHARED KEY mode) ++ 802.1x EAP via wpa_supplicant and xsupplicant ++ Wireless Extension support ++ Full B and G rate support (2200 and 2915) ++ Full A rate support (2915 only) ++ Transmit power control ++ S state support (ACPI suspend/resume) + +The following features are currently enabled, but not officially +supported: + ++ WPA ++ long/short preamble support ++ Monitor mode (aka RFMon) + +The distinction between officially supported and enabled is a reflection +on the amount of validation and interoperability testing that has been +performed on a given feature. + + + +1.2. Command Line Parameters +---------------------------- + +Like many modules used in the Linux kernel, the Intel(R) PRO/Wireless +2915ABG Driver for Linux allows configuration options to be provided +as module parameters. The most common way to specify a module parameter +is via the command line. + +The general form is:: + + % modprobe ipw2200 parameter=value + +Where the supported parameter are: + + associate + Set to 0 to disable the auto scan-and-associate functionality of the + driver. If disabled, the driver will not attempt to scan + for and associate to a network until it has been configured with + one or more properties for the target network, for example configuring + the network SSID. Default is 0 (do not auto-associate) + + Example: % modprobe ipw2200 associate=0 + + auto_create + Set to 0 to disable the auto creation of an Ad-Hoc network + matching the channel and network name parameters provided. + Default is 1. + + channel + channel number for association. The normal method for setting + the channel would be to use the standard wireless tools + (i.e. `iwconfig eth1 channel 10`), but it is useful sometimes + to set this while debugging. Channel 0 means 'ANY' + + debug + If using a debug build, this is used to control the amount of debug + info is logged. See the 'dvals' and 'load' script for more info on + how to use this (the dvals and load scripts are provided as part + of the ipw2200 development snapshot releases available from the + SourceForge project at http://ipw2200.sf.net) + + led + Can be used to turn on experimental LED code. + 0 = Off, 1 = On. Default is 1. + + mode + Can be used to set the default mode of the adapter. + 0 = Managed, 1 = Ad-Hoc, 2 = Monitor + + +1.3. Wireless Extension Private Methods +--------------------------------------- + +As an interface designed to handle generic hardware, there are certain +capabilities not exposed through the normal Wireless Tool interface. As +such, a provision is provided for a driver to declare custom, or +private, methods. The Intel(R) PRO/Wireless 2915ABG Driver for Linux +defines several of these to configure various settings. + +The general form of using the private wireless methods is:: + + % iwpriv $IFNAME method parameters + +Where $IFNAME is the interface name the device is registered with +(typically eth1, customized via one of the various network interface +name managers, such as ifrename) + +The supported private methods are: + + get_mode + Can be used to report out which IEEE mode the driver is + configured to support. Example: + + % iwpriv eth1 get_mode + eth1 get_mode:802.11bg (6) + + set_mode + Can be used to configure which IEEE mode the driver will + support. + + Usage:: + + % iwpriv eth1 set_mode {mode} + + Where {mode} is a number in the range 1-7: + + == ===================== + 1 802.11a (2915 only) + 2 802.11b + 3 802.11ab (2915 only) + 4 802.11g + 5 802.11ag (2915 only) + 6 802.11bg + 7 802.11abg (2915 only) + == ===================== + + get_preamble + Can be used to report configuration of preamble length. + + set_preamble + Can be used to set the configuration of preamble length: + + Usage:: + + % iwpriv eth1 set_preamble {mode} + + Where {mode} is one of: + + == ======================================== + 1 Long preamble only + 0 Auto (long or short based on connection) + == ======================================== + + +1.4. Sysfs Helper Files +----------------------- + +The Linux kernel provides a pseudo file system that can be used to +access various components of the operating system. The Intel(R) +PRO/Wireless 2915ABG Driver for Linux exposes several configuration +parameters through this mechanism. + +An entry in the sysfs can support reading and/or writing. You can +typically query the contents of a sysfs entry through the use of cat, +and can set the contents via echo. For example:: + + % cat /sys/bus/pci/drivers/ipw2200/debug_level + +Will report the current debug level of the driver's logging subsystem +(only available if CONFIG_IPW2200_DEBUG was configured when the driver +was built). + +You can set the debug level via:: + + % echo $VALUE > /sys/bus/pci/drivers/ipw2200/debug_level + +Where $VALUE would be a number in the case of this sysfs entry. The +input to sysfs files does not have to be a number. For example, the +firmware loader used by hotplug utilizes sysfs entries for transferring +the firmware image from user space into the driver. + +The Intel(R) PRO/Wireless 2915ABG Driver for Linux exposes sysfs entries +at two levels -- driver level, which apply to all instances of the driver +(in the event that there are more than one device installed) and device +level, which applies only to the single specific instance. + + +1.4.1 Driver Level Sysfs Helper Files +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +For the driver level files, look in /sys/bus/pci/drivers/ipw2200/ + + debug_level + This controls the same global as the 'debug' module parameter + + + +1.4.2 Device Level Sysfs Helper Files +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +For the device level files, look in:: + + /sys/bus/pci/drivers/ipw2200/{PCI-ID}/ + +For example::: + + /sys/bus/pci/drivers/ipw2200/0000:02:01.0 + +For the device level files, see /sys/bus/pci/drivers/ipw2200: + + rf_kill + read - + + == ========================================= + 0 RF kill not enabled (radio on) + 1 SW based RF kill active (radio off) + 2 HW based RF kill active (radio off) + 3 Both HW and SW RF kill active (radio off) + == ========================================= + + write - + + == ================================================== + 0 If SW based RF kill active, turn the radio back on + 1 If radio is on, activate SW based RF kill + == ================================================== + + .. note:: + + If you enable the SW based RF kill and then toggle the HW + based RF kill from ON -> OFF -> ON, the radio will NOT come back on + + ucode + read-only access to the ucode version number + + led + read - + + == ================= + 0 LED code disabled + 1 LED code enabled + == ================= + + write - + + == ================ + 0 Disable LED code + 1 Enable LED code + == ================ + + + .. note:: + + The LED code has been reported to hang some systems when + running ifconfig and is therefore disabled by default. + + +1.5. Supported channels +----------------------- + +Upon loading the Intel(R) PRO/Wireless 2915ABG Driver for Linux, a +message stating the detected geography code and the number of 802.11 +channels supported by the card will be displayed in the log. + +The geography code corresponds to a regulatory domain as shown in the +table below. + + +------+----------------------------+--------------------+ + | | | Supported channels | + | Code | Geography +----------+---------+ + | | | 802.11bg | 802.11a | + +======+============================+==========+=========+ + | --- | Restricted | 11 | 0 | + +------+----------------------------+----------+---------+ + | ZZF | Custom US/Canada | 11 | 8 | + +------+----------------------------+----------+---------+ + | ZZD | Rest of World | 13 | 0 | + +------+----------------------------+----------+---------+ + | ZZA | Custom USA & Europe & High | 11 | 13 | + +------+----------------------------+----------+---------+ + | ZZB | Custom NA & Europe | 11 | 13 | + +------+----------------------------+----------+---------+ + | ZZC | Custom Japan | 11 | 4 | + +------+----------------------------+----------+---------+ + | ZZM | Custom | 11 | 0 | + +------+----------------------------+----------+---------+ + | ZZE | Europe | 13 | 19 | + +------+----------------------------+----------+---------+ + | ZZJ | Custom Japan | 14 | 4 | + +------+----------------------------+----------+---------+ + | ZZR | Rest of World | 14 | 0 | + +------+----------------------------+----------+---------+ + | ZZH | High Band | 13 | 4 | + +------+----------------------------+----------+---------+ + | ZZG | Custom Europe | 13 | 4 | + +------+----------------------------+----------+---------+ + | ZZK | Europe | 13 | 24 | + +------+----------------------------+----------+---------+ + | ZZL | Europe | 11 | 13 | + +------+----------------------------+----------+---------+ + +2. Ad-Hoc Networking +===================== + +When using a device in an Ad-Hoc network, it is useful to understand the +sequence and requirements for the driver to be able to create, join, or +merge networks. + +The following attempts to provide enough information so that you can +have a consistent experience while using the driver as a member of an +Ad-Hoc network. + +2.1. Joining an Ad-Hoc Network +------------------------------ + +The easiest way to get onto an Ad-Hoc network is to join one that +already exists. + +2.2. Creating an Ad-Hoc Network +------------------------------- + +An Ad-Hoc networks is created using the syntax of the Wireless tool. + +For Example: +iwconfig eth1 mode ad-hoc essid testing channel 2 + +2.3. Merging Ad-Hoc Networks +---------------------------- + + +3. Interaction with Wireless Tools +================================== + +3.1 iwconfig mode +----------------- + +When configuring the mode of the adapter, all run-time configured parameters +are reset to the value used when the module was loaded. This includes +channels, rates, ESSID, etc. + +3.2 iwconfig sens +----------------- + +The 'iwconfig ethX sens XX' command will not set the signal sensitivity +threshold, as described in iwconfig documentation, but rather the number +of consecutive missed beacons that will trigger handover, i.e. roaming +to another access point. At the same time, it will set the disassociation +threshold to 3 times the given value. + + +4. About the Version Numbers +============================= + +Due to the nature of open source development projects, there are +frequently changes being incorporated that have not gone through +a complete validation process. These changes are incorporated into +development snapshot releases. + +Releases are numbered with a three level scheme: + + major.minor.development + +Any version where the 'development' portion is 0 (for example +1.0.0, 1.1.0, etc.) indicates a stable version that will be made +available for kernel inclusion. + +Any version where the 'development' portion is not a 0 (for +example 1.0.1, 1.1.5, etc.) indicates a development version that is +being made available for testing and cutting edge users. The stability +and functionality of the development releases are not know. We make +efforts to try and keep all snapshots reasonably stable, but due to the +frequency of their release, and the desire to get those releases +available as quickly as possible, unknown anomalies should be expected. + +The major version number will be incremented when significant changes +are made to the driver. Currently, there are no major changes planned. + +5. Firmware installation +======================== + +The driver requires a firmware image, download it and extract the +files under /lib/firmware (or wherever your hotplug's firmware.agent +will look for firmware files) + +The firmware can be downloaded from the following URL: + + http://ipw2200.sf.net/ + + +6. Support +========== + +For direct support of the 1.0.0 version, you can contact +http://supportmail.intel.com, or you can use the open source project +support. + +For general information and support, go to: + + http://ipw2200.sf.net/ + + +7. License +========== + + Copyright |copy| 2003 - 2006 Intel Corporation. All rights reserved. + + This program is free software; you can redistribute it and/or modify it + under the terms of the GNU General Public License version 2 as + published by the Free Software Foundation. + + This program is distributed in the hope that it will be useful, but WITHOUT + ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + more details. + + You should have received a copy of the GNU General Public License along with + this program; if not, write to the Free Software Foundation, Inc., 59 + Temple Place - Suite 330, Boston, MA 02111-1307, USA. + + The full GNU General Public License is included in this distribution in the + file called LICENSE. + + Contact Information: + + James P. Ketrenos <ipw2100-admin@linux.intel.com> + + Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497 + diff --git a/Documentation/networking/device_drivers/wifi/ray_cs.rst b/Documentation/networking/device_drivers/wifi/ray_cs.rst new file mode 100644 index 0000000000..9a46d1ae8f --- /dev/null +++ b/Documentation/networking/device_drivers/wifi/ray_cs.rst @@ -0,0 +1,165 @@ +.. SPDX-License-Identifier: GPL-2.0 + +.. include:: <isonum.txt> + +========================= +Raylink wireless LAN card +========================= + +September 21, 1999 + +Copyright |copy| 1998 Corey Thomas (corey@world.std.com) + +This file is the documentation for the Raylink Wireless LAN card driver for +Linux. The Raylink wireless LAN card is a PCMCIA card which provides IEEE +802.11 compatible wireless network connectivity at 1 and 2 megabits/second. +See http://www.raytheon.com/micro/raylink/ for more information on the Raylink +card. This driver is in early development and does have bugs. See the known +bugs and limitations at the end of this document for more information. +This driver also works with WebGear's Aviator 2.4 and Aviator Pro +wireless LAN cards. + +As of kernel 2.3.18, the ray_cs driver is part of the Linux kernel +source. My web page for the development of ray_cs is at +http://web.ralinktech.com/ralink/Home/Support/Linux.html +and I can be emailed at corey@world.std.com + +The kernel driver is based on ray_cs-1.62.tgz + +The driver at my web page is intended to be used as an add on to +David Hinds pcmcia package. All the command line parameters are +available when compiled as a module. When built into the kernel, only +the essid= string parameter is available via the kernel command line. +This will change after the method of sorting out parameters for all +the PCMCIA drivers is agreed upon. If you must have a built in driver +with nondefault parameters, they can be edited in +/usr/src/linux/drivers/net/pcmcia/ray_cs.c. Searching for module_param +will find them all. + +Information on card services is available at: + + http://pcmcia-cs.sourceforge.net/ + + +Card services user programs are still required for PCMCIA devices. +pcmcia-cs-3.1.1 or greater is required for the kernel version of +the driver. + +Currently, ray_cs is not part of David Hinds card services package, +so the following magic is required. + +At the end of the /etc/pcmcia/config.opts file, add the line: +source ./ray_cs.opts +This will make card services read the ray_cs.opts file +when starting. Create the file /etc/pcmcia/ray_cs.opts containing the +following:: + + #### start of /etc/pcmcia/ray_cs.opts ################### + # Configuration options for Raylink Wireless LAN PCMCIA card + device "ray_cs" + class "network" module "misc/ray_cs" + + card "RayLink PC Card WLAN Adapter" + manfid 0x01a6, 0x0000 + bind "ray_cs" + + module "misc/ray_cs" opts "" + #### end of /etc/pcmcia/ray_cs.opts ##################### + + +To join an existing network with +different parameters, contact the network administrator for the +configuration information, and edit /etc/pcmcia/ray_cs.opts. +Add the parameters below between the empty quotes. + +Parameters for ray_cs driver which may be specified in ray_cs.opts: + +=============== =============== ============================================= +bc integer 0 = normal mode (802.11 timing), + 1 = slow down inter frame timing to allow + operation with older breezecom access + points. + +beacon_period integer beacon period in Kilo-microseconds, + + legal values = must be integer multiple + of hop dwell + + default = 256 + +country integer 1 = USA (default), + 2 = Europe, + 3 = Japan, + 4 = Korea, + 5 = Spain, + 6 = France, + 7 = Israel, + 8 = Australia + +essid string ESS ID - network name to join + + string with maximum length of 32 chars + default value = "ADHOC_ESSID" + +hop_dwell integer hop dwell time in Kilo-microseconds + + legal values = 16,32,64,128(default),256 + +irq_mask integer linux standard 16 bit value 1bit/IRQ + + lsb is IRQ 0, bit 1 is IRQ 1 etc. + Used to restrict choice of IRQ's to use. + Recommended method for controlling + interrupts is in /etc/pcmcia/config.opts + +net_type integer 0 (default) = adhoc network, + 1 = infrastructure + +phy_addr string string containing new MAC address in + hex, must start with x eg + x00008f123456 + +psm integer 0 = continuously active, + 1 = power save mode (not useful yet) + +pc_debug integer (0-5) larger values for more verbose + logging. Replaces ray_debug. + +ray_debug integer Replaced with pc_debug + +ray_mem_speed integer defaults to 500 + +sniffer integer 0 = not sniffer (default), + 1 = sniffer which can be used to record all + network traffic using tcpdump or similar, + but no normal network use is allowed. + +translate integer 0 = no translation (encapsulate frames), + 1 = translation (RFC1042/802.1) +=============== =============== ============================================= + +More on sniffer mode: + +tcpdump does not understand 802.11 headers, so it can't +interpret the contents, but it can record to a file. This is only +useful for debugging 802.11 lowlevel protocols that are not visible to +linux. If you want to watch ftp xfers, or do similar things, you +don't need to use sniffer mode. Also, some packet types are never +sent up by the card, so you will never see them (ack, rts, cts, probe +etc.) There is a simple program (showcap) included in the ray_cs +package which parses the 802.11 headers. + +Known Problems and missing features + + Does not work with non x86 + + Does not work with SMP + + Support for defragmenting frames is not yet debugged, and in + fact is known to not work. I have never encountered a net set + up to fragment, but still, it should be fixed. + + The ioctl support is incomplete. The hardware address cannot be set + using ifconfig yet. If a different hardware address is needed, it may + be set using the phy_addr parameter in ray_cs.opts. This requires + a card insertion to take effect. diff --git a/Documentation/networking/device_drivers/wwan/index.rst b/Documentation/networking/device_drivers/wwan/index.rst new file mode 100644 index 0000000000..370d8264d5 --- /dev/null +++ b/Documentation/networking/device_drivers/wwan/index.rst @@ -0,0 +1,19 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +WWAN Device Drivers +=================== + +Contents: + +.. toctree:: + :maxdepth: 2 + + iosm + t7xx + +.. only:: subproject and html + + Indices + ======= + + * :ref:`genindex` diff --git a/Documentation/networking/device_drivers/wwan/iosm.rst b/Documentation/networking/device_drivers/wwan/iosm.rst new file mode 100644 index 0000000000..6f9e955af9 --- /dev/null +++ b/Documentation/networking/device_drivers/wwan/iosm.rst @@ -0,0 +1,96 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +.. Copyright (C) 2020-21 Intel Corporation + +.. _iosm_driver_doc: + +=========================================== +IOSM Driver for Intel M.2 PCIe based Modems +=========================================== +The IOSM (IPC over Shared Memory) driver is a WWAN PCIe host driver developed +for linux or chrome platform for data exchange over PCIe interface between +Host platform & Intel M.2 Modem. The driver exposes interface conforming to the +MBIM protocol [1]. Any front end application ( eg: Modem Manager) could easily +manage the MBIM interface to enable data communication towards WWAN. + +Basic usage +=========== +MBIM functions are inactive when unmanaged. The IOSM driver only provides a +userspace interface MBIM "WWAN PORT" representing MBIM control channel and does +not play any role in managing the functionality. It is the job of a userspace +application to detect port enumeration and enable MBIM functionality. + +Examples of few such userspace application are: +- mbimcli (included with the libmbim [2] library), and +- Modem Manager [3] + +Management Applications to carry out below required actions for establishing +MBIM IP session: +- open the MBIM control channel +- configure network connection settings +- connect to network +- configure IP network interface + +Management application development +================================== +The driver and userspace interfaces are described below. The MBIM protocol is +described in [1] Mobile Broadband Interface Model v1.0 Errata-1. + +MBIM control channel userspace ABI +---------------------------------- + +/dev/wwan0mbim0 character device +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +The driver exposes an MBIM interface to the MBIM function by implementing +MBIM WWAN Port. The userspace end of the control channel pipe is a +/dev/wwan0mbim0 character device. Application shall use this interface for +MBIM protocol communication. + +Fragmentation +~~~~~~~~~~~~~ +The userspace application is responsible for all control message fragmentation +and defragmentation as per MBIM specification. + +/dev/wwan0mbim0 write() +~~~~~~~~~~~~~~~~~~~~~~~ +The MBIM control messages from the management application must not exceed the +negotiated control message size. + +/dev/wwan0mbim0 read() +~~~~~~~~~~~~~~~~~~~~~~ +The management application must accept control messages of up the negotiated +control message size. + +MBIM data channel userspace ABI +------------------------------- + +wwan0-X network device +~~~~~~~~~~~~~~~~~~~~~~ +The IOSM driver exposes IP link interface "wwan0-X" of type "wwan" for IP +traffic. Iproute network utility is used for creating "wwan0-X" network +interface and for associating it with MBIM IP session. The Driver supports +up to 8 IP sessions for simultaneous IP communication. + +The userspace management application is responsible for creating new IP link +prior to establishing MBIM IP session where the SessionId is greater than 0. + +For example, creating new IP link for a MBIM IP session with SessionId 1: + + ip link add dev wwan0-1 parentdev-name wwan0 type wwan linkid 1 + +The driver will automatically map the "wwan0-1" network device to MBIM IP +session 1. + +References +========== +[1] "MBIM (Mobile Broadband Interface Model) Errata-1" + - https://www.usb.org/document-library/ + +[2] libmbim - "a glib-based library for talking to WWAN modems and + devices which speak the Mobile Interface Broadband Model (MBIM) + protocol" + - http://www.freedesktop.org/wiki/Software/libmbim/ + +[3] Modem Manager - "a DBus-activated daemon which controls mobile + broadband (2G/3G/4G) devices and connections" + - http://www.freedesktop.org/wiki/Software/ModemManager/ diff --git a/Documentation/networking/device_drivers/wwan/t7xx.rst b/Documentation/networking/device_drivers/wwan/t7xx.rst new file mode 100644 index 0000000000..dd5b731957 --- /dev/null +++ b/Documentation/networking/device_drivers/wwan/t7xx.rst @@ -0,0 +1,120 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +.. Copyright (C) 2020-21 Intel Corporation + +.. _t7xx_driver_doc: + +============================================ +t7xx driver for MTK PCIe based T700 5G modem +============================================ +The t7xx driver is a WWAN PCIe host driver developed for linux or Chrome OS platforms +for data exchange over PCIe interface between Host platform & MediaTek's T700 5G modem. +The driver exposes an interface conforming to the MBIM protocol [1]. Any front end +application (e.g. Modem Manager) could easily manage the MBIM interface to enable +data communication towards WWAN. The driver also provides an interface to interact +with the MediaTek's modem via AT commands. + +Basic usage +=========== +MBIM & AT functions are inactive when unmanaged. The t7xx driver provides +WWAN port userspace interfaces representing MBIM & AT control channels and does +not play any role in managing their functionality. It is the job of a userspace +application to detect port enumeration and enable MBIM & AT functionalities. + +Examples of few such userspace applications are: + +- mbimcli (included with the libmbim [2] library), and +- Modem Manager [3] + +Management Applications to carry out below required actions for establishing +MBIM IP session: + +- open the MBIM control channel +- configure network connection settings +- connect to network +- configure IP network interface + +Management Applications to carry out below required actions for send an AT +command and receive response: + +- open the AT control channel using a UART tool or a special user tool + +Management application development +================================== +The driver and userspace interfaces are described below. The MBIM protocol is +described in [1] Mobile Broadband Interface Model v1.0 Errata-1. + +MBIM control channel userspace ABI +---------------------------------- + +/dev/wwan0mbim0 character device +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +The driver exposes an MBIM interface to the MBIM function by implementing +MBIM WWAN Port. The userspace end of the control channel pipe is a +/dev/wwan0mbim0 character device. Application shall use this interface for +MBIM protocol communication. + +Fragmentation +~~~~~~~~~~~~~ +The userspace application is responsible for all control message fragmentation +and defragmentation as per MBIM specification. + +/dev/wwan0mbim0 write() +~~~~~~~~~~~~~~~~~~~~~~~ +The MBIM control messages from the management application must not exceed the +negotiated control message size. + +/dev/wwan0mbim0 read() +~~~~~~~~~~~~~~~~~~~~~~ +The management application must accept control messages of up the negotiated +control message size. + +MBIM data channel userspace ABI +------------------------------- + +wwan0-X network device +~~~~~~~~~~~~~~~~~~~~~~ +The t7xx driver exposes IP link interface "wwan0-X" of type "wwan" for IP +traffic. Iproute network utility is used for creating "wwan0-X" network +interface and for associating it with MBIM IP session. + +The userspace management application is responsible for creating new IP link +prior to establishing MBIM IP session where the SessionId is greater than 0. + +For example, creating new IP link for a MBIM IP session with SessionId 1: + + ip link add dev wwan0-1 parentdev wwan0 type wwan linkid 1 + +The driver will automatically map the "wwan0-1" network device to MBIM IP +session 1. + +AT port userspace ABI +---------------------------------- + +/dev/wwan0at0 character device +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +The driver exposes an AT port by implementing AT WWAN Port. +The userspace end of the control port is a /dev/wwan0at0 character +device. Application shall use this interface to issue AT commands. + +The MediaTek's T700 modem supports the 3GPP TS 27.007 [4] specification. + +References +========== +[1] *MBIM (Mobile Broadband Interface Model) Errata-1* + +- https://www.usb.org/document-library/ + +[2] *libmbim "a glib-based library for talking to WWAN modems and devices which +speak the Mobile Interface Broadband Model (MBIM) protocol"* + +- http://www.freedesktop.org/wiki/Software/libmbim/ + +[3] *Modem Manager "a DBus-activated daemon which controls mobile broadband +(2G/3G/4G/5G) devices and connections"* + +- http://www.freedesktop.org/wiki/Software/ModemManager/ + +[4] *Specification # 27.007 - 3GPP* + +- https://www.3gpp.org/DynaReport/27007.htm diff --git a/Documentation/networking/devlink/am65-nuss-cpsw-switch.rst b/Documentation/networking/devlink/am65-nuss-cpsw-switch.rst new file mode 100644 index 0000000000..1e589c26ab --- /dev/null +++ b/Documentation/networking/devlink/am65-nuss-cpsw-switch.rst @@ -0,0 +1,26 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================== +am65-cpsw-nuss devlink support +============================== + +This document describes the devlink features implemented by the ``am65-cpsw-nuss`` +device driver. + +Parameters +========== + +The ``am65-cpsw-nuss`` driver implements the following driver-specific +parameters. + +.. list-table:: Driver-specific parameters implemented + :widths: 5 5 5 85 + + * - Name + - Type + - Mode + - Description + * - ``switch_mode`` + - Boolean + - runtime + - Enable switch mode diff --git a/Documentation/networking/devlink/bnxt.rst b/Documentation/networking/devlink/bnxt.rst new file mode 100644 index 0000000000..a4fb27663c --- /dev/null +++ b/Documentation/networking/devlink/bnxt.rst @@ -0,0 +1,82 @@ +.. SPDX-License-Identifier: GPL-2.0 + +==================== +bnxt devlink support +==================== + +This document describes the devlink features implemented by the ``bnxt`` +device driver. + +Parameters +========== + +.. list-table:: Generic parameters implemented + + * - Name + - Mode + * - ``enable_sriov`` + - Permanent + * - ``ignore_ari`` + - Permanent + * - ``msix_vec_per_pf_max`` + - Permanent + * - ``msix_vec_per_pf_min`` + - Permanent + * - ``enable_remote_dev_reset`` + - Runtime + +The ``bnxt`` driver also implements the following driver-specific +parameters. + +.. list-table:: Driver-specific parameters implemented + :widths: 5 5 5 85 + + * - Name + - Type + - Mode + - Description + * - ``gre_ver_check`` + - Boolean + - Permanent + - Generic Routing Encapsulation (GRE) version check will be enabled in + the device. If disabled, the device will skip the version check for + incoming packets. + +Info versions +============= + +The ``bnxt_en`` driver reports the following versions + +.. list-table:: devlink info versions implemented + :widths: 5 5 90 + + * - Name + - Type + - Description + * - ``board.id`` + - fixed + - Part number identifying the board design + * - ``asic.id`` + - fixed + - ASIC design identifier + * - ``asic.rev`` + - fixed + - ASIC design revision + * - ``fw.psid`` + - stored, running + - Firmware parameter set version of the board + * - ``fw`` + - stored, running + - Overall board firmware version + * - ``fw.mgmt`` + - stored, running + - NIC hardware resource management firmware version + * - ``fw.mgmt.api`` + - running + - Minimum firmware interface spec version supported between driver and firmware + * - ``fw.nsci`` + - stored, running + - General platform management firmware version + * - ``fw.roce`` + - stored, running + - RoCE management firmware version diff --git a/Documentation/networking/devlink/devlink-dpipe.rst b/Documentation/networking/devlink/devlink-dpipe.rst new file mode 100644 index 0000000000..af37f250df --- /dev/null +++ b/Documentation/networking/devlink/devlink-dpipe.rst @@ -0,0 +1,252 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============= +Devlink DPIPE +============= + +Background +========== + +While performing the hardware offloading process, much of the hardware +specifics cannot be presented. These details are useful for debugging, and +``devlink-dpipe`` provides a standardized way to provide visibility into the +offloading process. + +For example, the routing longest prefix match (LPM) algorithm used by the +Linux kernel may differ from the hardware implementation. The pipeline debug +API (DPIPE) is aimed at providing the user visibility into the ASIC's +pipeline in a generic way. + +The hardware offload process is expected to be done in a way that the user +should not be able to distinguish between the hardware vs. software +implementation. In this process, hardware specifics are neglected. In +reality those details can have lots of meaning and should be exposed in some +standard way. + +This problem is made even more complex when one wishes to offload the +control path of the whole networking stack to a switch ASIC. Due to +differences in the hardware and software models some processes cannot be +represented correctly. + +One example is the kernel's LPM algorithm which in many cases differs +greatly to the hardware implementation. The configuration API is the same, +but one cannot rely on the Forward Information Base (FIB) to look like the +Level Path Compression trie (LPC-trie) in hardware. + +In many situations trying to analyze systems failure solely based on the +kernel's dump may not be enough. By combining this data with complementary +information about the underlying hardware, this debugging can be made +easier; additionally, the information can be useful when debugging +performance issues. + +Overview +======== + +The ``devlink-dpipe`` interface closes this gap. The hardware's pipeline is +modeled as a graph of match/action tables. Each table represents a specific +hardware block. This model is not new, first being used by the P4 language. + +Traditionally it has been used as an alternative model for hardware +configuration, but the ``devlink-dpipe`` interface uses it for visibility +purposes as a standard complementary tool. The system's view from +``devlink-dpipe`` should change according to the changes done by the +standard configuration tools. + +For example, it’s quite common to implement Access Control Lists (ACL) +using Ternary Content Addressable Memory (TCAM). The TCAM memory can be +divided into TCAM regions. Complex TC filters can have multiple rules with +different priorities and different lookup keys. On the other hand hardware +TCAM regions have a predefined lookup key. Offloading the TC filter rules +using TCAM engine can result in multiple TCAM regions being interconnected +in a chain (which may affect the data path latency). In response to a new TC +filter new tables should be created describing those regions. + +Model +===== + +The ``DPIPE`` model introduces several objects: + + * headers + * tables + * entries + +A ``header`` describes packet formats and provides names for fields within +the packet. A ``table`` describes hardware blocks. An ``entry`` describes +the actual content of a specific table. + +The hardware pipeline is not port specific, but rather describes the whole +ASIC. Thus it is tied to the top of the ``devlink`` infrastructure. + +Drivers can register and unregister tables at run time, in order to support +dynamic behavior. This dynamic behavior is mandatory for describing hardware +blocks like TCAM regions which can be allocated and freed dynamically. + +``devlink-dpipe`` generally is not intended for configuration. The exception +is hardware counting for a specific table. + +The following commands are used to obtain the ``dpipe`` objects from +userspace: + + * ``table_get``: Receive a table's description. + * ``headers_get``: Receive a device's supported headers. + * ``entries_get``: Receive a table's current entries. + * ``counters_set``: Enable or disable counters on a table. + +Table +----- + +The driver should implement the following operations for each table: + + * ``matches_dump``: Dump the supported matches. + * ``actions_dump``: Dump the supported actions. + * ``entries_dump``: Dump the actual content of the table. + * ``counters_set_update``: Synchronize hardware with counters enabled or + disabled. + +Header/Field +------------ + +In a similar way to P4 headers and fields are used to describe a table's +behavior. There is a slight difference between the standard protocol headers +and specific ASIC metadata. The protocol headers should be declared in the +``devlink`` core API. On the other hand ASIC meta data is driver specific +and should be defined in the driver. Additionally, each driver-specific +devlink documentation file should document the driver-specific ``dpipe`` +headers it implements. The headers and fields are identified by enumeration. + +In order to provide further visibility some ASIC metadata fields could be +mapped to kernel objects. For example, internal router interface indexes can +be directly mapped to the net device ifindex. FIB table indexes used by +different Virtual Routing and Forwarding (VRF) tables can be mapped to +internal routing table indexes. + +Match +----- + +Matches are kept primitive and close to hardware operation. Match types like +LPM are not supported due to the fact that this is exactly a process we wish +to describe in full detail. Example of matches: + + * ``field_exact``: Exact match on a specific field. + * ``field_exact_mask``: Exact match on a specific field after masking. + * ``field_range``: Match on a specific range. + +The id's of the header and the field should be specified in order to +identify the specific field. Furthermore, the header index should be +specified in order to distinguish multiple headers of the same type in a +packet (tunneling). + +Action +------ + +Similar to match, the actions are kept primitive and close to hardware +operation. For example: + + * ``field_modify``: Modify the field value. + * ``field_inc``: Increment the field value. + * ``push_header``: Add a header. + * ``pop_header``: Remove a header. + +Entry +----- + +Entries of a specific table can be dumped on demand. Each eentry is +identified with an index and its properties are described by a list of +match/action values and specific counter. By dumping the tables content the +interactions between tables can be resolved. + +Abstraction Example +=================== + +The following is an example of the abstraction model of the L3 part of +Mellanox Spectrum ASIC. The blocks are described in the order they appear in +the pipeline. The table sizes in the following examples are not real +hardware sizes and are provided for demonstration purposes. + +LPM +--- + +The LPM algorithm can be implemented as a list of hash tables. Each hash +table contains routes with the same prefix length. The root of the list is +/32, and in case of a miss the hardware will continue to the next hash +table. The depth of the search will affect the data path latency. + +In case of a hit the entry contains information about the next stage of the +pipeline which resolves the MAC address. The next stage can be either local +host table for directly connected routes, or adjacency table for next-hops. +The ``meta.lpm_prefix`` field is used to connect two LPM tables. + +.. code:: + + table lpm_prefix_16 { + size: 4096, + counters_enabled: true, + match: { meta.vr_id: exact, + ipv4.dst_addr: exact_mask, + ipv6.dst_addr: exact_mask, + meta.lpm_prefix: exact }, + action: { meta.adj_index: set, + meta.adj_group_size: set, + meta.rif_port: set, + meta.lpm_prefix: set }, + } + +Local Host +---------- + +In the case of local routes the LPM lookup already resolves the egress +router interface (RIF), yet the exact MAC address is not known. The local +host table is a hash table combining the output interface id with +destination IP address as a key. The result is the MAC address. + +.. code:: + + table local_host { + size: 4096, + counters_enabled: true, + match: { meta.rif_port: exact, + ipv4.dst_addr: exact}, + action: { ethernet.daddr: set } + } + +Adjacency +--------- + +In case of remote routes this table does the ECMP. The LPM lookup results in +ECMP group size and index that serves as a global offset into this table. +Concurrently a hash of the packet is generated. Based on the ECMP group size +and the packet's hash a local offset is generated. Multiple LPM entries can +point to the same adjacency group. + +.. code:: + + table adjacency { + size: 4096, + counters_enabled: true, + match: { meta.adj_index: exact, + meta.adj_group_size: exact, + meta.packet_hash_index: exact }, + action: { ethernet.daddr: set, + meta.erif: set } + } + +ERIF +---- + +In case the egress RIF and destination MAC have been resolved by previous +tables this table does multiple operations like TTL decrease and MTU check. +Then the decision of forward/drop is taken and the port L3 statistics are +updated based on the packet's type (broadcast, unicast, multicast). + +.. code:: + + table erif { + size: 800, + counters_enabled: true, + match: { meta.rif_port: exact, + meta.is_l3_unicast: exact, + meta.is_l3_broadcast: exact, + meta.is_l3_multicast, exact }, + action: { meta.l3_drop: set, + meta.l3_forward: set } + } diff --git a/Documentation/networking/devlink/devlink-flash.rst b/Documentation/networking/devlink/devlink-flash.rst new file mode 100644 index 0000000000..603e732f00 --- /dev/null +++ b/Documentation/networking/devlink/devlink-flash.rst @@ -0,0 +1,121 @@ +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) + +.. _devlink_flash: + +============= +Devlink Flash +============= + +The ``devlink-flash`` API allows updating device firmware. It replaces the +older ``ethtool-flash`` mechanism, and doesn't require taking any +networking locks in the kernel to perform the flash update. Example use:: + + $ devlink dev flash pci/0000:05:00.0 file flash-boot.bin + +Note that the file name is a path relative to the firmware loading path +(usually ``/lib/firmware/``). Drivers may send status updates to inform +user space about the progress of the update operation. + +Overwrite Mask +============== + +The ``devlink-flash`` command allows optionally specifying a mask indicating +how the device should handle subsections of flash components when updating. +This mask indicates the set of sections which are allowed to be overwritten. + +.. list-table:: List of overwrite mask bits + :widths: 5 95 + + * - Name + - Description + * - ``DEVLINK_FLASH_OVERWRITE_SETTINGS`` + - Indicates that the device should overwrite settings in the components + being updated with the settings found in the provided image. + * - ``DEVLINK_FLASH_OVERWRITE_IDENTIFIERS`` + - Indicates that the device should overwrite identifiers in the + components being updated with the identifiers found in the provided + image. This includes MAC addresses, serial IDs, and similar device + identifiers. + +Multiple overwrite bits may be combined and requested together. If no bits +are provided, it is expected that the device only update firmware binaries +in the components being updated. Settings and identifiers are expected to be +preserved across the update. A device may not support every combination and +the driver for such a device must reject any combination which cannot be +faithfully implemented. + +Firmware Loading +================ + +Devices which require firmware to operate usually store it in non-volatile +memory on the board, e.g. flash. Some devices store only basic firmware on +the board, and the driver loads the rest from disk during probing. +``devlink-info`` allows users to query firmware information (loaded +components and versions). + +In other cases the device can both store the image on the board, load from +disk, or automatically flash a new image from disk. The ``fw_load_policy`` +devlink parameter can be used to control this behavior +(:ref:`Documentation/networking/devlink/devlink-params.rst <devlink_params_generic>`). + +On-disk firmware files are usually stored in ``/lib/firmware/``. + +Firmware Version Management +=========================== + +Drivers are expected to implement ``devlink-flash`` and ``devlink-info`` +functionality, which together allow for implementing vendor-independent +automated firmware update facilities. + +``devlink-info`` exposes the ``driver`` name and three version groups +(``fixed``, ``running``, ``stored``). + +The ``driver`` attribute and ``fixed`` group identify the specific device +design, e.g. for looking up applicable firmware updates. This is why +``serial_number`` is not part of the ``fixed`` versions (even though it +is fixed) - ``fixed`` versions should identify the design, not a single +device. + +``running`` and ``stored`` firmware versions identify the firmware running +on the device, and firmware which will be activated after reboot or device +reset. + +The firmware update agent is supposed to be able to follow this simple +algorithm to update firmware contents, regardless of the device vendor: + +.. code-block:: sh + + # Get unique HW design identifier + $hw_id = devlink-dev-info['fixed'] + + # Find out which FW flash we want to use for this NIC + $want_flash_vers = some-db-backed.lookup($hw_id, 'flash') + + # Update flash if necessary + if $want_flash_vers != devlink-dev-info['stored']: + $file = some-db-backed.download($hw_id, 'flash') + devlink-dev-flash($file) + + # Find out the expected overall firmware versions + $want_fw_vers = some-db-backed.lookup($hw_id, 'all') + + # Update on-disk file if necessary + if $want_fw_vers != devlink-dev-info['running']: + $file = some-db-backed.download($hw_id, 'disk') + write($file, '/lib/firmware/') + + # Try device reset, if available + if $want_fw_vers != devlink-dev-info['running']: + devlink-reset() + + # Reboot, if reset wasn't enough + if $want_fw_vers != devlink-dev-info['running']: + reboot() + +Note that each reference to ``devlink-dev-info`` in this pseudo-code +is expected to fetch up-to-date information from the kernel. + +For the convenience of identifying firmware files some vendors add +``bundle_id`` information to the firmware versions. This meta-version covers +multiple per-component versions and can be used e.g. in firmware file names +(all component versions could get rather long.) diff --git a/Documentation/networking/devlink/devlink-health.rst b/Documentation/networking/devlink/devlink-health.rst new file mode 100644 index 0000000000..e0b8cfed61 --- /dev/null +++ b/Documentation/networking/devlink/devlink-health.rst @@ -0,0 +1,138 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============== +Devlink Health +============== + +Background +========== + +The ``devlink`` health mechanism is targeted for Real Time Alerting, in +order to know when something bad happened to a PCI device. + + * Provide alert debug information. + * Self healing. + * If problem needs vendor support, provide a way to gather all needed + debugging information. + +Overview +======== + +The main idea is to unify and centralize driver health reports in the +generic ``devlink`` instance and allow the user to set different +attributes of the health reporting and recovery procedures. + +The ``devlink`` health reporter: +Device driver creates a "health reporter" per each error/health type. +Error/Health type can be a known/generic (e.g. PCI error, fw error, rx/tx error) +or unknown (driver specific). +For each registered health reporter a driver can issue error/health reports +asynchronously. All health reports handling is done by ``devlink``. +Device driver can provide specific callbacks for each "health reporter", e.g.: + + * Recovery procedures + * Diagnostics procedures + * Object dump procedures + * Out Of Box initial parameters + +Different parts of the driver can register different types of health reporters +with different handlers. + +Actions +======= + +Once an error is reported, devlink health will perform the following actions: + + * A log is being send to the kernel trace events buffer + * Health status and statistics are being updated for the reporter instance + * Object dump is being taken and saved at the reporter instance (as long as + auto-dump is set and there is no other dump which is already stored) + * Auto recovery attempt is being done. Depends on: + + - Auto-recovery configuration + - Grace period vs. time passed since last recover + +Devlink formatted message +========================= + +To handle devlink health diagnose and health dump requests, devlink creates a +formatted message structure ``devlink_fmsg`` and send it to the driver's callback +to fill the data in using the devlink fmsg API. + +Devlink fmsg is a mechanism to pass descriptors between drivers and devlink, in +json-like format. The API allows the driver to add nested attributes such as +object, object pair and value array, in addition to attributes such as name and +value. + +Driver should use this API to fill the fmsg context in a format which will be +translated by the devlink to the netlink message later. When it needs to send +the data using SKBs to the netlink layer, it fragments the data between +different SKBs. In order to do this fragmentation, it uses virtual nests +attributes, to avoid actual nesting use which cannot be divided between +different SKBs. + +User Interface +============== + +User can access/change each reporter's parameters and driver specific callbacks +via ``devlink``, e.g per error type (per health reporter): + + * Configure reporter's generic parameters (like: disable/enable auto recovery) + * Invoke recovery procedure + * Run diagnostics + * Object dump + +.. list-table:: List of devlink health interfaces + :widths: 10 90 + + * - Name + - Description + * - ``DEVLINK_CMD_HEALTH_REPORTER_GET`` + - Retrieves status and configuration info per DEV and reporter. + * - ``DEVLINK_CMD_HEALTH_REPORTER_SET`` + - Allows reporter-related configuration setting. + * - ``DEVLINK_CMD_HEALTH_REPORTER_RECOVER`` + - Triggers reporter's recovery procedure. + * - ``DEVLINK_CMD_HEALTH_REPORTER_TEST`` + - Triggers a fake health event on the reporter. The effects of the test + event in terms of recovery flow should follow closely that of a real + event. + * - ``DEVLINK_CMD_HEALTH_REPORTER_DIAGNOSE`` + - Retrieves current device state related to the reporter. + * - ``DEVLINK_CMD_HEALTH_REPORTER_DUMP_GET`` + - Retrieves the last stored dump. Devlink health + saves a single dump. If an dump is not already stored by devlink + for this reporter, devlink generates a new dump. + Dump output is defined by the reporter. + * - ``DEVLINK_CMD_HEALTH_REPORTER_DUMP_CLEAR`` + - Clears the last saved dump file for the specified reporter. + +The following diagram provides a general overview of ``devlink-health``:: + + netlink + +--------------------------+ + | | + | + | + | | | + +--------------------------+ + |request for ops + |(diagnose, + driver devlink |recover, + |dump) + +--------+ +--------------------------+ + | | | reporter| | + | | | +---------v----------+ | + | | ops execution | | | | + | <----------------------------------+ | | + | | | | | | + | | | + ^------------------+ | + | | | | request for ops | + | | | | (recover, dump) | + | | | | | + | | | +-+------------------+ | + | | health report | | health handler | | + | +-------------------------------> | | + | | | +--------------------+ | + | | health reporter create | | + | +----------------------------> | + +--------+ +--------------------------+ diff --git a/Documentation/networking/devlink/devlink-info.rst b/Documentation/networking/devlink/devlink-info.rst new file mode 100644 index 0000000000..1242b0e682 --- /dev/null +++ b/Documentation/networking/devlink/devlink-info.rst @@ -0,0 +1,215 @@ +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) + +============ +Devlink Info +============ + +The ``devlink-info`` mechanism enables device drivers to report device +(hardware and firmware) information in a standard, extensible fashion. + +The original motivation for the ``devlink-info`` API was twofold: + + - making it possible to automate device and firmware management in a fleet + of machines in a vendor-independent fashion (see also + :ref:`Documentation/networking/devlink/devlink-flash.rst <devlink_flash>`); + - name the per component FW versions (as opposed to the crowded ethtool + version string). + +``devlink-info`` supports reporting multiple types of objects. Reporting driver +versions is generally discouraged - here, and via any other Linux API. + +.. list-table:: List of top level info objects + :widths: 5 95 + + * - Name + - Description + * - ``driver`` + - Name of the currently used device driver, also available through sysfs. + + * - ``serial_number`` + - Serial number of the device. + + This is usually the serial number of the ASIC, also often available + in PCI config space of the device in the *Device Serial Number* + capability. + + The serial number should be unique per physical device. + Sometimes the serial number of the device is only 48 bits long (the + length of the Ethernet MAC address), and since PCI DSN is 64 bits long + devices pad or encode additional information into the serial number. + One example is adding port ID or PCI interface ID in the extra two bytes. + Drivers should make sure to strip or normalize any such padding + or interface ID, and report only the part of the serial number + which uniquely identifies the hardware. In other words serial number + reported for two ports of the same device or on two hosts of + a multi-host device should be identical. + + * - ``board.serial_number`` + - Board serial number of the device. + + This is usually the serial number of the board, often available in + PCI *Vital Product Data*. + + * - ``fixed`` + - Group for hardware identifiers, and versions of components + which are not field-updatable. + + Versions in this section identify the device design. For example, + component identifiers or the board version reported in the PCI VPD. + Data in ``devlink-info`` should be broken into the smallest logical + components, e.g. PCI VPD may concatenate various information + to form the Part Number string, while in ``devlink-info`` all parts + should be reported as separate items. + + This group must not contain any frequently changing identifiers, + such as serial numbers. See + :ref:`Documentation/networking/devlink/devlink-flash.rst <devlink_flash>` + to understand why. + + * - ``running`` + - Group for information about currently running software/firmware. + These versions often only update after a reboot, sometimes device reset. + + * - ``stored`` + - Group for software/firmware versions in device flash. + + Stored values must update to reflect changes in the flash even + if reboot has not yet occurred. If device is not capable of updating + ``stored`` versions when new software is flashed, it must not report + them. + +Each version can be reported at most once in each version group. Firmware +components stored on the flash should feature in both the ``running`` and +``stored`` sections, if device is capable of reporting ``stored`` versions +(see :ref:`Documentation/networking/devlink/devlink-flash.rst <devlink_flash>`). +In case software/firmware components are loaded from the disk (e.g. +``/lib/firmware``) only the running version should be reported via +the kernel API. + +Generic Versions +================ + +It is expected that drivers use the following generic names for exporting +version information. If a generic name for a given component doesn't exist yet, +driver authors should consult existing driver-specific versions and attempt +reuse. As last resort, if a component is truly unique, using driver-specific +names is allowed, but these should be documented in the driver-specific file. + +All versions should try to use the following terminology: + +.. list-table:: List of common version suffixes + :widths: 10 90 + + * - Name + - Description + * - ``id``, ``revision`` + - Identifiers of designs and revision, mostly used for hardware versions. + + * - ``api`` + - Version of API between components. API items are usually of limited + value to the user, and can be inferred from other versions by the vendor, + so adding API versions is generally discouraged as noise. + + * - ``bundle_id`` + - Identifier of a distribution package which was flashed onto the device. + This is an attribute of a firmware package which covers multiple versions + for ease of managing firmware images (see + :ref:`Documentation/networking/devlink/devlink-flash.rst <devlink_flash>`). + + ``bundle_id`` can appear in both ``running`` and ``stored`` versions, + but it must not be reported if any of the components covered by the + ``bundle_id`` was changed and no longer matches the version from + the bundle. + +board.id +-------- + +Unique identifier of the board design. + +board.rev +--------- + +Board design revision. + +asic.id +------- + +ASIC design identifier. + +asic.rev +-------- + +ASIC design revision/stepping. + +board.manufacture +----------------- + +An identifier of the company or the facility which produced the part. + +fw +-- + +Overall firmware version, often representing the collection of +fw.mgmt, fw.app, etc. + +fw.mgmt +------- + +Control unit firmware version. This firmware is responsible for house +keeping tasks, PHY control etc. but not the packet-by-packet data path +operation. + +fw.mgmt.api +----------- + +Firmware interface specification version of the software interfaces between +driver and firmware. + +fw.app +------ + +Data path microcode controlling high-speed packet processing. + +fw.undi +------- + +UNDI software, may include the UEFI driver, firmware or both. + +fw.ncsi +------- + +Version of the software responsible for supporting/handling the +Network Controller Sideband Interface. + +fw.psid +------- + +Unique identifier of the firmware parameter set. These are usually +parameters of a particular board, defined at manufacturing time. + +fw.roce +------- + +RoCE firmware version which is responsible for handling roce +management. + +fw.bundle_id +------------ + +Unique identifier of the entire firmware bundle. + +fw.bootloader +------------- + +Version of the bootloader. + +Future work +=========== + +The following extensions could be useful: + + - on-disk firmware file names - drivers list the file names of firmware they + may need to load onto devices via the ``MODULE_FIRMWARE()`` macro. These, + however, are per module, rather than per device. It'd be useful to list + the names of firmware files the driver will try to load for a given device, + in order of priority. diff --git a/Documentation/networking/devlink/devlink-linecard.rst b/Documentation/networking/devlink/devlink-linecard.rst new file mode 100644 index 0000000000..6c0b8928bc --- /dev/null +++ b/Documentation/networking/devlink/devlink-linecard.rst @@ -0,0 +1,122 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================= +Devlink Line card +================= + +Background +========== + +The ``devlink-linecard`` mechanism is targeted for manipulation of +line cards that serve as a detachable PHY modules for modular switch +system. Following operations are provided: + + * Get a list of supported line card types. + * Provision of a slot with specific line card type. + * Get and monitor of line card state and its change. + +Line card according to the type may contain one or more gearboxes +to mux the lanes with certain speed to multiple ports with lanes +of different speed. Line card ensures N:M mapping between +the switch ASIC modules and physical front panel ports. + +Overview +======== + +Each line card devlink object is created by device driver, +according to the physical line card slots available on the device. + +Similar to splitter cable, where the device might have no way +of detection of the splitter cable geometry, the device +might not have a way to detect line card type. For that devices, +concept of provisioning is introduced. It allows the user to: + + * Provision a line card slot with certain line card type + + - Device driver would instruct the ASIC to prepare all + resources accordingly. The device driver would + create all instances, namely devlink port and netdevices + that reside on the line card, according to the line card type + * Manipulate of line card entities even without line card + being physically connected or powered-up + * Setup splitter cable on line card ports + + - As on the ordinary ports, user may provision a splitter + cable of a certain type, without the need to + be physically connected to the port + * Configure devlink ports and netdevices + +Netdevice carrier is decided as follows: + + * Line card is not inserted or powered-down + + - The carrier is always down + * Line card is inserted and powered up + + - The carrier is decided as for ordinary port netdevice + +Line card state +=============== + +The ``devlink-linecard`` mechanism supports the following line card states: + + * ``unprovisioned``: Line card is not provisioned on the slot. + * ``unprovisioning``: Line card slot is currently being unprovisioned. + * ``provisioning``: Line card slot is currently in a process of being provisioned + with a line card type. + * ``provisioning_failed``: Provisioning was not successful. + * ``provisioned``: Line card slot is provisioned with a type. + * ``active``: Line card is powered-up and active. + +The following diagram provides a general overview of ``devlink-linecard`` +state transitions:: + + +-------------------------+ + | | + +----------------------------------> unprovisioned | + | | | + | +--------|-------^--------+ + | | | + | | | + | +--------v-------|--------+ + | | | + | | provisioning | + | | | + | +------------|------------+ + | | + | +-----------------------------+ + | | | + | +------------v------------+ +------------v------------+ +-------------------------+ + | | | | ----> | + +----- provisioning_failed | | provisioned | | active | + | | | | <---- | + | +------------^------------+ +------------|------------+ +-------------------------+ + | | | + | | | + | | +------------v------------+ + | | | | + | | | unprovisioning | + | | | | + | | +------------|------------+ + | | | + | +-----------------------------+ + | | + +-----------------------------------------------+ + + +Example usage +============= + +.. code:: shell + + $ devlink lc show [ DEV [ lc LC_INDEX ] ] + $ devlink lc set DEV lc LC_INDEX [ { type LC_TYPE | notype } ] + + # Show current line card configuration and status for all slots: + $ devlink lc + + # Set slot 8 to be provisioned with type "16x100G": + $ devlink lc set pci/0000:01:00.0 lc 8 type 16x100G + + # Set slot 8 to be unprovisioned: + $ devlink lc set pci/0000:01:00.0 lc 8 notype diff --git a/Documentation/networking/devlink/devlink-params.rst b/Documentation/networking/devlink/devlink-params.rst new file mode 100644 index 0000000000..4e01dc32bc --- /dev/null +++ b/Documentation/networking/devlink/devlink-params.rst @@ -0,0 +1,139 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============== +Devlink Params +============== + +``devlink`` provides capability for a driver to expose device parameters for low +level device functionality. Since devlink can operate at the device-wide +level, it can be used to provide configuration that may affect multiple +ports on a single device. + +This document describes a number of generic parameters that are supported +across multiple drivers. Each driver is also free to add their own +parameters. Each driver must document the specific parameters they support, +whether generic or not. + +Configuration modes +=================== + +Parameters may be set in different configuration modes. + +.. list-table:: Possible configuration modes + :widths: 5 90 + + * - Name + - Description + * - ``runtime`` + - set while the driver is running, and takes effect immediately. No + reset is required. + * - ``driverinit`` + - applied while the driver initializes. Requires the user to restart + the driver using the ``devlink`` reload command. + * - ``permanent`` + - written to the device's non-volatile memory. A hard reset is required + for it to take effect. + +Reloading +--------- + +In order for ``driverinit`` parameters to take effect, the driver must +support reloading via the ``devlink-reload`` command. This command will +request a reload of the device driver. + +.. _devlink_params_generic: + +Generic configuration parameters +================================ +The following is a list of generic configuration parameters that drivers may +add. Use of generic parameters is preferred over each driver creating their +own name. + +.. list-table:: List of generic parameters + :widths: 5 5 90 + + * - Name + - Type + - Description + * - ``enable_sriov`` + - Boolean + - Enable Single Root I/O Virtualization (SRIOV) in the device. + * - ``ignore_ari`` + - Boolean + - Ignore Alternative Routing-ID Interpretation (ARI) capability. If + enabled, the adapter will ignore ARI capability even when the + platform has support enabled. The device will create the same number + of partitions as when the platform does not support ARI. + * - ``msix_vec_per_pf_max`` + - u32 + - Provides the maximum number of MSI-X interrupts that a device can + create. Value is the same across all physical functions (PFs) in the + device. + * - ``msix_vec_per_pf_min`` + - u32 + - Provides the minimum number of MSI-X interrupts required for the + device to initialize. Value is the same across all physical functions + (PFs) in the device. + * - ``fw_load_policy`` + - u8 + - Control the device's firmware loading policy. + - ``DEVLINK_PARAM_FW_LOAD_POLICY_VALUE_DRIVER`` (0) + Load firmware version preferred by the driver. + - ``DEVLINK_PARAM_FW_LOAD_POLICY_VALUE_FLASH`` (1) + Load firmware currently stored in flash. + - ``DEVLINK_PARAM_FW_LOAD_POLICY_VALUE_DISK`` (2) + Load firmware currently available on host's disk. + * - ``reset_dev_on_drv_probe`` + - u8 + - Controls the device's reset policy on driver probe. + - ``DEVLINK_PARAM_RESET_DEV_ON_DRV_PROBE_VALUE_UNKNOWN`` (0) + Unknown or invalid value. + - ``DEVLINK_PARAM_RESET_DEV_ON_DRV_PROBE_VALUE_ALWAYS`` (1) + Always reset device on driver probe. + - ``DEVLINK_PARAM_RESET_DEV_ON_DRV_PROBE_VALUE_NEVER`` (2) + Never reset device on driver probe. + - ``DEVLINK_PARAM_RESET_DEV_ON_DRV_PROBE_VALUE_DISK`` (3) + Reset the device only if firmware can be found in the filesystem. + * - ``enable_roce`` + - Boolean + - Enable handling of RoCE traffic in the device. + * - ``enable_eth`` + - Boolean + - When enabled, the device driver will instantiate Ethernet specific + auxiliary device of the devlink device. + * - ``enable_rdma`` + - Boolean + - When enabled, the device driver will instantiate RDMA specific + auxiliary device of the devlink device. + * - ``enable_vnet`` + - Boolean + - When enabled, the device driver will instantiate VDPA networking + specific auxiliary device of the devlink device. + * - ``enable_iwarp`` + - Boolean + - Enable handling of iWARP traffic in the device. + * - ``internal_err_reset`` + - Boolean + - When enabled, the device driver will reset the device on internal + errors. + * - ``max_macs`` + - u32 + - Typically macvlan, vlan net devices mac are also programmed in their + parent netdevice's Function rx filter. This parameter limit the + maximum number of unicast mac address filters to receive traffic from + per ethernet port of this device. + * - ``region_snapshot_enable`` + - Boolean + - Enable capture of ``devlink-region`` snapshots. + * - ``enable_remote_dev_reset`` + - Boolean + - Enable device reset by remote host. When cleared, the device driver + will NACK any attempt of other host to reset the device. This parameter + is useful for setups where a device is shared by different hosts, such + as multi-host setup. + * - ``io_eq_size`` + - u32 + - Control the size of I/O completion EQs. + * - ``event_eq_size`` + - u32 + - Control the size of asynchronous control events EQ. diff --git a/Documentation/networking/devlink/devlink-port.rst b/Documentation/networking/devlink/devlink-port.rst new file mode 100644 index 0000000000..e33ad2401a --- /dev/null +++ b/Documentation/networking/devlink/devlink-port.rst @@ -0,0 +1,443 @@ +.. SPDX-License-Identifier: GPL-2.0 + +.. _devlink_port: + +============ +Devlink Port +============ + +``devlink-port`` is a port that exists on the device. It has a logically +separate ingress/egress point of the device. A devlink port can be any one +of many flavours. A devlink port flavour along with port attributes +describe what a port represents. + +A device driver that intends to publish a devlink port sets the +devlink port attributes and registers the devlink port. + +Devlink port flavours are described below. + +.. list-table:: List of devlink port flavours + :widths: 33 90 + + * - Flavour + - Description + * - ``DEVLINK_PORT_FLAVOUR_PHYSICAL`` + - Any kind of physical port. This can be an eswitch physical port or any + other physical port on the device. + * - ``DEVLINK_PORT_FLAVOUR_DSA`` + - This indicates a DSA interconnect port. + * - ``DEVLINK_PORT_FLAVOUR_CPU`` + - This indicates a CPU port applicable only to DSA. + * - ``DEVLINK_PORT_FLAVOUR_PCI_PF`` + - This indicates an eswitch port representing a port of PCI + physical function (PF). + * - ``DEVLINK_PORT_FLAVOUR_PCI_VF`` + - This indicates an eswitch port representing a port of PCI + virtual function (VF). + * - ``DEVLINK_PORT_FLAVOUR_PCI_SF`` + - This indicates an eswitch port representing a port of PCI + subfunction (SF). + * - ``DEVLINK_PORT_FLAVOUR_VIRTUAL`` + - This indicates a virtual port for the PCI virtual function. + +Devlink port can have a different type based on the link layer described below. + +.. list-table:: List of devlink port types + :widths: 23 90 + + * - Type + - Description + * - ``DEVLINK_PORT_TYPE_ETH`` + - Driver should set this port type when a link layer of the port is + Ethernet. + * - ``DEVLINK_PORT_TYPE_IB`` + - Driver should set this port type when a link layer of the port is + InfiniBand. + * - ``DEVLINK_PORT_TYPE_AUTO`` + - This type is indicated by the user when driver should detect the port + type automatically. + +PCI controllers +--------------- +In most cases a PCI device has only one controller. A controller consists of +potentially multiple physical, virtual functions and subfunctions. A function +consists of one or more ports. This port is represented by the devlink eswitch +port. + +A PCI device connected to multiple CPUs or multiple PCI root complexes or a +SmartNIC, however, may have multiple controllers. For a device with multiple +controllers, each controller is distinguished by a unique controller number. +An eswitch is on the PCI device which supports ports of multiple controllers. + +An example view of a system with two controllers:: + + --------------------------------------------------------- + | | + | --------- --------- ------- ------- | + ----------- | | vf(s) | | sf(s) | |vf(s)| |sf(s)| | + | server | | ------- ----/---- ---/----- ------- ---/--- ---/--- | + | pci rc |=== | pf0 |______/________/ | pf1 |___/_______/ | + | connect | | ------- ------- | + ----------- | | controller_num=1 (no eswitch) | + ------|-------------------------------------------------- + (internal wire) + | + --------------------------------------------------------- + | devlink eswitch ports and reps | + | ----------------------------------------------------- | + | |ctrl-0 | ctrl-0 | ctrl-0 | ctrl-0 | ctrl-0 |ctrl-0 | | + | |pf0 | pf0vfN | pf0sfN | pf1 | pf1vfN |pf1sfN | | + | ----------------------------------------------------- | + | |ctrl-1 | ctrl-1 | ctrl-1 | ctrl-1 | ctrl-1 |ctrl-1 | | + | |pf0 | pf0vfN | pf0sfN | pf1 | pf1vfN |pf1sfN | | + | ----------------------------------------------------- | + | | + | | + ----------- | --------- --------- ------- ------- | + | smartNIC| | | vf(s) | | sf(s) | |vf(s)| |sf(s)| | + | pci rc |==| ------- ----/---- ---/----- ------- ---/--- ---/--- | + | connect | | | pf0 |______/________/ | pf1 |___/_______/ | + ----------- | ------- ------- | + | | + | local controller_num=0 (eswitch) | + --------------------------------------------------------- + +In the above example, the external controller (identified by controller number = 1) +doesn't have the eswitch. Local controller (identified by controller number = 0) +has the eswitch. The Devlink instance on the local controller has eswitch +devlink ports for both the controllers. + +Function configuration +====================== + +Users can configure one or more function attributes before enumerating the PCI +function. Usually it means, user should configure function attribute +before a bus specific device for the function is created. However, when +SRIOV is enabled, virtual function devices are created on the PCI bus. +Hence, function attribute should be configured before binding virtual +function device to the driver. For subfunctions, this means user should +configure port function attribute before activating the port function. + +A user may set the hardware address of the function using +`devlink port function set hw_addr` command. For Ethernet port function +this means a MAC address. + +Users may also set the RoCE capability of the function using +`devlink port function set roce` command. + +Users may also set the function as migratable using +'devlink port function set migratable' command. + +Users may also set the IPsec crypto capability of the function using +`devlink port function set ipsec_crypto` command. + +Users may also set the IPsec packet capability of the function using +`devlink port function set ipsec_packet` command. + +Function attributes +=================== + +MAC address setup +----------------- +The configured MAC address of the PCI VF/SF will be used by netdevice and rdma +device created for the PCI VF/SF. + +- Get the MAC address of the VF identified by its unique devlink port index:: + + $ devlink port show pci/0000:06:00.0/2 + pci/0000:06:00.0/2: type eth netdev enp6s0pf0vf1 flavour pcivf pfnum 0 vfnum 1 + function: + hw_addr 00:00:00:00:00:00 + +- Set the MAC address of the VF identified by its unique devlink port index:: + + $ devlink port function set pci/0000:06:00.0/2 hw_addr 00:11:22:33:44:55 + + $ devlink port show pci/0000:06:00.0/2 + pci/0000:06:00.0/2: type eth netdev enp6s0pf0vf1 flavour pcivf pfnum 0 vfnum 1 + function: + hw_addr 00:11:22:33:44:55 + +- Get the MAC address of the SF identified by its unique devlink port index:: + + $ devlink port show pci/0000:06:00.0/32768 + pci/0000:06:00.0/32768: type eth netdev enp6s0pf0sf88 flavour pcisf pfnum 0 sfnum 88 + function: + hw_addr 00:00:00:00:00:00 + +- Set the MAC address of the SF identified by its unique devlink port index:: + + $ devlink port function set pci/0000:06:00.0/32768 hw_addr 00:00:00:00:88:88 + + $ devlink port show pci/0000:06:00.0/32768 + pci/0000:06:00.0/32768: type eth netdev enp6s0pf0sf88 flavour pcisf pfnum 0 sfnum 88 + function: + hw_addr 00:00:00:00:88:88 + +RoCE capability setup +--------------------- +Not all PCI VFs/SFs require RoCE capability. + +When RoCE capability is disabled, it saves system memory per PCI VF/SF. + +When user disables RoCE capability for a VF/SF, user application cannot send or +receive any RoCE packets through this VF/SF and RoCE GID table for this PCI +will be empty. + +When RoCE capability is disabled in the device using port function attribute, +VF/SF driver cannot override it. + +- Get RoCE capability of the VF device:: + + $ devlink port show pci/0000:06:00.0/2 + pci/0000:06:00.0/2: type eth netdev enp6s0pf0vf1 flavour pcivf pfnum 0 vfnum 1 + function: + hw_addr 00:00:00:00:00:00 roce enable + +- Set RoCE capability of the VF device:: + + $ devlink port function set pci/0000:06:00.0/2 roce disable + + $ devlink port show pci/0000:06:00.0/2 + pci/0000:06:00.0/2: type eth netdev enp6s0pf0vf1 flavour pcivf pfnum 0 vfnum 1 + function: + hw_addr 00:00:00:00:00:00 roce disable + +migratable capability setup +--------------------------- +Live migration is the process of transferring a live virtual machine +from one physical host to another without disrupting its normal +operation. + +User who want PCI VFs to be able to perform live migration need to +explicitly enable the VF migratable capability. + +When user enables migratable capability for a VF, and the HV binds the VF to VFIO driver +with migration support, the user can migrate the VM with this VF from one HV to a +different one. + +However, when migratable capability is enable, device will disable features which cannot +be migrated. Thus migratable cap can impose limitations on a VF so let the user decide. + +Example of LM with migratable function configuration: +- Get migratable capability of the VF device:: + + $ devlink port show pci/0000:06:00.0/2 + pci/0000:06:00.0/2: type eth netdev enp6s0pf0vf1 flavour pcivf pfnum 0 vfnum 1 + function: + hw_addr 00:00:00:00:00:00 migratable disable + +- Set migratable capability of the VF device:: + + $ devlink port function set pci/0000:06:00.0/2 migratable enable + + $ devlink port show pci/0000:06:00.0/2 + pci/0000:06:00.0/2: type eth netdev enp6s0pf0vf1 flavour pcivf pfnum 0 vfnum 1 + function: + hw_addr 00:00:00:00:00:00 migratable enable + +- Bind VF to VFIO driver with migration support:: + + $ echo <pci_id> > /sys/bus/pci/devices/0000:08:00.0/driver/unbind + $ echo mlx5_vfio_pci > /sys/bus/pci/devices/0000:08:00.0/driver_override + $ echo <pci_id> > /sys/bus/pci/devices/0000:08:00.0/driver/bind + +Attach VF to the VM. +Start the VM. +Perform live migration. + +IPsec crypto capability setup +----------------------------- +When user enables IPsec crypto capability for a VF, user application can offload +XFRM state crypto operation (Encrypt/Decrypt) to this VF. + +When IPsec crypto capability is disabled (default) for a VF, the XFRM state is +processed in software by the kernel. + +- Get IPsec crypto capability of the VF device:: + + $ devlink port show pci/0000:06:00.0/2 + pci/0000:06:00.0/2: type eth netdev enp6s0pf0vf1 flavour pcivf pfnum 0 vfnum 1 + function: + hw_addr 00:00:00:00:00:00 ipsec_crypto disabled + +- Set IPsec crypto capability of the VF device:: + + $ devlink port function set pci/0000:06:00.0/2 ipsec_crypto enable + + $ devlink port show pci/0000:06:00.0/2 + pci/0000:06:00.0/2: type eth netdev enp6s0pf0vf1 flavour pcivf pfnum 0 vfnum 1 + function: + hw_addr 00:00:00:00:00:00 ipsec_crypto enabled + +IPsec packet capability setup +----------------------------- +When user enables IPsec packet capability for a VF, user application can offload +XFRM state and policy crypto operation (Encrypt/Decrypt) to this VF, as well as +IPsec encapsulation. + +When IPsec packet capability is disabled (default) for a VF, the XFRM state and +policy is processed in software by the kernel. + +- Get IPsec packet capability of the VF device:: + + $ devlink port show pci/0000:06:00.0/2 + pci/0000:06:00.0/2: type eth netdev enp6s0pf0vf1 flavour pcivf pfnum 0 vfnum 1 + function: + hw_addr 00:00:00:00:00:00 ipsec_packet disabled + +- Set IPsec packet capability of the VF device:: + + $ devlink port function set pci/0000:06:00.0/2 ipsec_packet enable + + $ devlink port show pci/0000:06:00.0/2 + pci/0000:06:00.0/2: type eth netdev enp6s0pf0vf1 flavour pcivf pfnum 0 vfnum 1 + function: + hw_addr 00:00:00:00:00:00 ipsec_packet enabled + +Subfunction +============ + +Subfunction is a lightweight function that has a parent PCI function on which +it is deployed. Subfunction is created and deployed in unit of 1. Unlike +SRIOV VFs, a subfunction doesn't require its own PCI virtual function. +A subfunction communicates with the hardware through the parent PCI function. + +To use a subfunction, 3 steps setup sequence is followed: + +1) create - create a subfunction; +2) configure - configure subfunction attributes; +3) deploy - deploy the subfunction; + +Subfunction management is done using devlink port user interface. +User performs setup on the subfunction management device. + +(1) Create +---------- +A subfunction is created using a devlink port interface. A user adds the +subfunction by adding a devlink port of subfunction flavour. The devlink +kernel code calls down to subfunction management driver (devlink ops) and asks +it to create a subfunction devlink port. Driver then instantiates the +subfunction port and any associated objects such as health reporters and +representor netdevice. + +(2) Configure +------------- +A subfunction devlink port is created but it is not active yet. That means the +entities are created on devlink side, the e-switch port representor is created, +but the subfunction device itself is not created. A user might use e-switch port +representor to do settings, putting it into bridge, adding TC rules, etc. A user +might as well configure the hardware address (such as MAC address) of the +subfunction while subfunction is inactive. + +(3) Deploy +---------- +Once a subfunction is configured, user must activate it to use it. Upon +activation, subfunction management driver asks the subfunction management +device to instantiate the subfunction device on particular PCI function. +A subfunction device is created on the :ref:`Documentation/driver-api/auxiliary_bus.rst <auxiliary_bus>`. +At this point a matching subfunction driver binds to the subfunction's auxiliary device. + +Rate object management +====================== + +Devlink provides API to manage tx rates of single devlink port or a group. +This is done through rate objects, which can be one of the two types: + +``leaf`` + Represents a single devlink port; created/destroyed by the driver. Since leaf + have 1to1 mapping to its devlink port, in user space it is referred as + ``pci/<bus_addr>/<port_index>``; + +``node`` + Represents a group of rate objects (leafs and/or nodes); created/deleted by + request from the userspace; initially empty (no rate objects added). In + userspace it is referred as ``pci/<bus_addr>/<node_name>``, where + ``node_name`` can be any identifier, except decimal number, to avoid + collisions with leafs. + +API allows to configure following rate object's parameters: + +``tx_share`` + Minimum TX rate value shared among all other rate objects, or rate objects + that parts of the parent group, if it is a part of the same group. + +``tx_max`` + Maximum TX rate value. + +``tx_priority`` + Allows for usage of strict priority arbiter among siblings. This + arbitration scheme attempts to schedule nodes based on their priority + as long as the nodes remain within their bandwidth limit. The higher the + priority the higher the probability that the node will get selected for + scheduling. + +``tx_weight`` + Allows for usage of Weighted Fair Queuing arbitration scheme among + siblings. This arbitration scheme can be used simultaneously with the + strict priority. As a node is configured with a higher rate it gets more + BW relative to its siblings. Values are relative like a percentage + points, they basically tell how much BW should node take relative to + its siblings. + +``parent`` + Parent node name. Parent node rate limits are considered as additional limits + to all node children limits. ``tx_max`` is an upper limit for children. + ``tx_share`` is a total bandwidth distributed among children. + +``tx_priority`` and ``tx_weight`` can be used simultaneously. In that case +nodes with the same priority form a WFQ subgroup in the sibling group +and arbitration among them is based on assigned weights. + +Arbitration flow from the high level: + +#. Choose a node, or group of nodes with the highest priority that stays + within the BW limit and are not blocked. Use ``tx_priority`` as a + parameter for this arbitration. + +#. If group of nodes have the same priority perform WFQ arbitration on + that subgroup. Use ``tx_weight`` as a parameter for this arbitration. + +#. Select the winner node, and continue arbitration flow among its children, + until leaf node is reached, and the winner is established. + +#. If all the nodes from the highest priority sub-group are satisfied, or + overused their assigned BW, move to the lower priority nodes. + +Driver implementations are allowed to support both or either rate object types +and setting methods of their parameters. Additionally driver implementation +may export nodes/leafs and their child-parent relationships. + +Terms and Definitions +===================== + +.. list-table:: Terms and Definitions + :widths: 22 90 + + * - Term + - Definitions + * - ``PCI device`` + - A physical PCI device having one or more PCI buses consists of one or + more PCI controllers. + * - ``PCI controller`` + - A controller consists of potentially multiple physical functions, + virtual functions and subfunctions. + * - ``Port function`` + - An object to manage the function of a port. + * - ``Subfunction`` + - A lightweight function that has parent PCI function on which it is + deployed. + * - ``Subfunction device`` + - A bus device of the subfunction, usually on a auxiliary bus. + * - ``Subfunction driver`` + - A device driver for the subfunction auxiliary device. + * - ``Subfunction management device`` + - A PCI physical function that supports subfunction management. + * - ``Subfunction management driver`` + - A device driver for PCI physical function that supports + subfunction management using devlink port interface. + * - ``Subfunction host driver`` + - A device driver for PCI physical function that hosts subfunction + devices. In most cases it is same as subfunction management driver. When + subfunction is used on external controller, subfunction management and + host drivers are different. diff --git a/Documentation/networking/devlink/devlink-region.rst b/Documentation/networking/devlink/devlink-region.rst new file mode 100644 index 0000000000..9232cd7da3 --- /dev/null +++ b/Documentation/networking/devlink/devlink-region.rst @@ -0,0 +1,83 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============== +Devlink Region +============== + +``devlink`` regions enable access to driver defined address regions using +devlink. + +Each device can create and register its own supported address regions. The +region can then be accessed via the devlink region interface. + +Region snapshots are collected by the driver, and can be accessed via read +or dump commands. This allows future analysis on the created snapshots. +Regions may optionally support triggering snapshots on demand. + +Snapshot identifiers are scoped to the devlink instance, not a region. +All snapshots with the same snapshot id within a devlink instance +correspond to the same event. + +The major benefit to creating a region is to provide access to internal +address regions that are otherwise inaccessible to the user. + +Regions may also be used to provide an additional way to debug complex error +states, but see also Documentation/networking/devlink/devlink-health.rst + +Regions may optionally support capturing a snapshot on demand via the +``DEVLINK_CMD_REGION_NEW`` netlink message. A driver wishing to allow +requested snapshots must implement the ``.snapshot`` callback for the region +in its ``devlink_region_ops`` structure. If snapshot id is not set in +the ``DEVLINK_CMD_REGION_NEW`` request kernel will allocate one and send +the snapshot information to user space. + +Regions may optionally allow directly reading from their contents without a +snapshot. Direct read requests are not atomic. In particular a read request +of size 256 bytes or larger will be split into multiple chunks. If atomic +access is required, use a snapshot. A driver wishing to enable this for a +region should implement the ``.read`` callback in the ``devlink_region_ops`` +structure. User space can request a direct read by using the +``DEVLINK_ATTR_REGION_DIRECT`` attribute instead of specifying a snapshot +id. + +example usage +------------- + +.. code:: shell + + $ devlink region help + $ devlink region show [ DEV/REGION ] + $ devlink region del DEV/REGION snapshot SNAPSHOT_ID + $ devlink region dump DEV/REGION [ snapshot SNAPSHOT_ID ] + $ devlink region read DEV/REGION [ snapshot SNAPSHOT_ID ] address ADDRESS length length + + # Show all of the exposed regions with region sizes: + $ devlink region show + pci/0000:00:05.0/cr-space: size 1048576 snapshot [1 2] max 8 + pci/0000:00:05.0/fw-health: size 64 snapshot [1 2] max 8 + + # Delete a snapshot using: + $ devlink region del pci/0000:00:05.0/cr-space snapshot 1 + + # Request an immediate snapshot, if supported by the region + $ devlink region new pci/0000:00:05.0/cr-space + pci/0000:00:05.0/cr-space: snapshot 5 + + # Dump a snapshot: + $ devlink region dump pci/0000:00:05.0/fw-health snapshot 1 + 0000000000000000 0014 95dc 0014 9514 0035 1670 0034 db30 + 0000000000000010 0000 0000 ffff ff04 0029 8c00 0028 8cc8 + 0000000000000020 0016 0bb8 0016 1720 0000 0000 c00f 3ffc + 0000000000000030 bada cce5 bada cce5 bada cce5 bada cce5 + + # Read a specific part of a snapshot: + $ devlink region read pci/0000:00:05.0/fw-health snapshot 1 address 0 length 16 + 0000000000000000 0014 95dc 0014 9514 0035 1670 0034 db30 + + # Read from the region without a snapshot + $ devlink region read pci/0000:00:05.0/fw-health address 16 length 16 + 0000000000000010 0000 0000 ffff ff04 0029 8c00 0028 8cc8 + +As regions are likely very device or driver specific, no generic regions are +defined. See the driver-specific documentation files for information on the +specific regions a driver supports. diff --git a/Documentation/networking/devlink/devlink-reload.rst b/Documentation/networking/devlink/devlink-reload.rst new file mode 100644 index 0000000000..505d22da02 --- /dev/null +++ b/Documentation/networking/devlink/devlink-reload.rst @@ -0,0 +1,81 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============== +Devlink Reload +============== + +``devlink-reload`` provides mechanism to reinit driver entities, applying +``devlink-params`` and ``devlink-resources`` new values. It also provides +mechanism to activate firmware. + +Reload Actions +============== + +User may select a reload action. +By default ``driver_reinit`` action is selected. + +.. list-table:: Possible reload actions + :widths: 5 90 + + * - Name + - Description + * - ``driver-reinit`` + - Devlink driver entities re-initialization, including applying + new values to devlink entities which are used during driver + load such as ``devlink-params`` in configuration mode + ``driverinit`` or ``devlink-resources`` + * - ``fw_activate`` + - Firmware activate. Activates new firmware if such image is stored and + pending activation. If no limitation specified this action may involve + firmware reset. If no new image pending this action will reload current + firmware image. + +Note that even though user asks for a specific action, the driver +implementation might require to perform another action alongside with +it. For example, some driver do not support driver reinitialization +being performed without fw activation. Therefore, the devlink reload +command returns the list of actions which were actrually performed. + +Reload Limits +============= + +By default reload actions are not limited and driver implementation may +include reset or downtime as needed to perform the actions. + +However, some drivers support action limits, which limit the action +implementation to specific constraints. + +.. list-table:: Possible reload limits + :widths: 5 90 + + * - Name + - Description + * - ``no_reset`` + - No reset allowed, no down time allowed, no link flap and no + configuration is lost. + +Change Namespace +================ + +The netns option allows user to be able to move devlink instances into +namespaces during devlink reload operation. +By default all devlink instances are created in init_net and stay there. + +example usage +------------- + +.. code:: shell + + $ devlink dev reload help + $ devlink dev reload DEV [ netns { PID | NAME | ID } ] [ action { driver_reinit | fw_activate } ] [ limit no_reset ] + + # Run reload command for devlink driver entities re-initialization: + $ devlink dev reload pci/0000:82:00.0 action driver_reinit + reload_actions_performed: + driver_reinit + + # Run reload command to activate firmware: + # Note that mlx5 driver reloads the driver while activating firmware + $ devlink dev reload pci/0000:82:00.0 action fw_activate + reload_actions_performed: + driver_reinit fw_activate diff --git a/Documentation/networking/devlink/devlink-resource.rst b/Documentation/networking/devlink/devlink-resource.rst new file mode 100644 index 0000000000..3d5ae51e65 --- /dev/null +++ b/Documentation/networking/devlink/devlink-resource.rst @@ -0,0 +1,76 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================ +Devlink Resource +================ + +``devlink`` provides the ability for drivers to register resources, which +can allow administrators to see the device restrictions for a given +resource, as well as how much of the given resource is currently +in use. Additionally, these resources can optionally have configurable size. +This could enable the administrator to limit the number of resources that +are used. + +For example, the ``netdevsim`` driver enables ``/IPv4/fib`` and +``/IPv4/fib-rules`` as resources to limit the number of IPv4 FIB entries and +rules for a given device. + +Resource Ids +============ + +Each resource is represented by an id, and contains information about its +current size and related sub resources. To access a sub resource, you +specify the path of the resource. For example ``/IPv4/fib`` is the id for +the ``fib`` sub-resource under the ``IPv4`` resource. + +Generic Resources +================= + +Generic resources are used to describe resources that can be shared by multiple +device drivers and their description must be added to the following table: + +.. list-table:: List of Generic Resources + :widths: 10 90 + + * - Name + - Description + * - ``physical_ports`` + - A limited capacity of physical ports that the switch ASIC can support + +example usage +------------- + +The resources exposed by the driver can be observed, for example: + +.. code:: shell + + $devlink resource show pci/0000:03:00.0 + pci/0000:03:00.0: + name kvd size 245760 unit entry + resources: + name linear size 98304 occ 0 unit entry size_min 0 size_max 147456 size_gran 128 + name hash_double size 60416 unit entry size_min 32768 size_max 180224 size_gran 128 + name hash_single size 87040 unit entry size_min 65536 size_max 212992 size_gran 128 + +Some resource's size can be changed. Examples: + +.. code:: shell + + $devlink resource set pci/0000:03:00.0 path /kvd/hash_single size 73088 + $devlink resource set pci/0000:03:00.0 path /kvd/hash_double size 74368 + +The changes do not apply immediately, this can be validated by the 'size_new' +attribute, which represents the pending change in size. For example: + +.. code:: shell + + $devlink resource show pci/0000:03:00.0 + pci/0000:03:00.0: + name kvd size 245760 unit entry size_valid false + resources: + name linear size 98304 size_new 147456 occ 0 unit entry size_min 0 size_max 147456 size_gran 128 + name hash_double size 60416 unit entry size_min 32768 size_max 180224 size_gran 128 + name hash_single size 87040 unit entry size_min 65536 size_max 212992 size_gran 128 + +Note that changes in resource size may require a device reload to properly +take effect. diff --git a/Documentation/networking/devlink/devlink-selftests.rst b/Documentation/networking/devlink/devlink-selftests.rst new file mode 100644 index 0000000000..c0aa1f3aef --- /dev/null +++ b/Documentation/networking/devlink/devlink-selftests.rst @@ -0,0 +1,38 @@ +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) + +================= +Devlink Selftests +================= + +The ``devlink-selftests`` API allows executing selftests on the device. + +Tests Mask +========== +The ``devlink-selftests`` command should be run with a mask indicating +the tests to be executed. + +Tests Description +================= +The following is a list of tests that drivers may execute. + +.. list-table:: List of tests + :widths: 5 90 + + * - Name + - Description + * - ``DEVLINK_SELFTEST_FLASH`` + - Devices may have the firmware on non-volatile memory on the board, e.g. + flash. This particular test helps to run a flash selftest on the device. + Implementation of the test is left to the driver/firmware. + +example usage +------------- + +.. code:: shell + + # Query selftests supported on the devlink device + $ devlink dev selftests show DEV + # Query selftests supported on all devlink devices + $ devlink dev selftests show + # Executes selftests on the device + $ devlink dev selftests run DEV id flash diff --git a/Documentation/networking/devlink/devlink-trap.rst b/Documentation/networking/devlink/devlink-trap.rst new file mode 100644 index 0000000000..2c14dfe69b --- /dev/null +++ b/Documentation/networking/devlink/devlink-trap.rst @@ -0,0 +1,640 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============ +Devlink Trap +============ + +Background +========== + +Devices capable of offloading the kernel's datapath and perform functions such +as bridging and routing must also be able to send specific packets to the +kernel (i.e., the CPU) for processing. + +For example, a device acting as a multicast-aware bridge must be able to send +IGMP membership reports to the kernel for processing by the bridge module. +Without processing such packets, the bridge module could never populate its +MDB. + +As another example, consider a device acting as router which has received an IP +packet with a TTL of 1. Upon routing the packet the device must send it to the +kernel so that it will route it as well and generate an ICMP Time Exceeded +error datagram. Without letting the kernel route such packets itself, utilities +such as ``traceroute`` could never work. + +The fundamental ability of sending certain packets to the kernel for processing +is called "packet trapping". + +Overview +======== + +The ``devlink-trap`` mechanism allows capable device drivers to register their +supported packet traps with ``devlink`` and report trapped packets to +``devlink`` for further analysis. + +Upon receiving trapped packets, ``devlink`` will perform a per-trap packets and +bytes accounting and potentially report the packet to user space via a netlink +event along with all the provided metadata (e.g., trap reason, timestamp, input +port). This is especially useful for drop traps (see :ref:`Trap-Types`) +as it allows users to obtain further visibility into packet drops that would +otherwise be invisible. + +The following diagram provides a general overview of ``devlink-trap``:: + + Netlink event: Packet w/ metadata + Or a summary of recent drops + ^ + | + Userspace | + +---------------------------------------------------+ + Kernel | + | + +-------+--------+ + | | + | drop_monitor | + | | + +-------^--------+ + | + | Non-control traps + | + +----+----+ + | | Kernel's Rx path + | devlink | (non-drop traps) + | | + +----^----+ ^ + | | + +-----------+ + | + +-------+-------+ + | | + | Device driver | + | | + +-------^-------+ + Kernel | + +---------------------------------------------------+ + Hardware | + | Trapped packet + | + +--+---+ + | | + | ASIC | + | | + +------+ + +.. _Trap-Types: + +Trap Types +========== + +The ``devlink-trap`` mechanism supports the following packet trap types: + + * ``drop``: Trapped packets were dropped by the underlying device. Packets + are only processed by ``devlink`` and not injected to the kernel's Rx path. + The trap action (see :ref:`Trap-Actions`) can be changed. + * ``exception``: Trapped packets were not forwarded as intended by the + underlying device due to an exception (e.g., TTL error, missing neighbour + entry) and trapped to the control plane for resolution. Packets are + processed by ``devlink`` and injected to the kernel's Rx path. Changing the + action of such traps is not allowed, as it can easily break the control + plane. + * ``control``: Trapped packets were trapped by the device because these are + control packets required for the correct functioning of the control plane. + For example, ARP request and IGMP query packets. Packets are injected to + the kernel's Rx path, but not reported to the kernel's drop monitor. + Changing the action of such traps is not allowed, as it can easily break + the control plane. + +.. _Trap-Actions: + +Trap Actions +============ + +The ``devlink-trap`` mechanism supports the following packet trap actions: + + * ``trap``: The sole copy of the packet is sent to the CPU. + * ``drop``: The packet is dropped by the underlying device and a copy is not + sent to the CPU. + * ``mirror``: The packet is forwarded by the underlying device and a copy is + sent to the CPU. + +Generic Packet Traps +==================== + +Generic packet traps are used to describe traps that trap well-defined packets +or packets that are trapped due to well-defined conditions (e.g., TTL error). +Such traps can be shared by multiple device drivers and their description must +be added to the following table: + +.. list-table:: List of Generic Packet Traps + :widths: 5 5 90 + + * - Name + - Type + - Description + * - ``source_mac_is_multicast`` + - ``drop`` + - Traps incoming packets that the device decided to drop because of a + multicast source MAC + * - ``vlan_tag_mismatch`` + - ``drop`` + - Traps incoming packets that the device decided to drop in case of VLAN + tag mismatch: The ingress bridge port is not configured with a PVID and + the packet is untagged or prio-tagged + * - ``ingress_vlan_filter`` + - ``drop`` + - Traps incoming packets that the device decided to drop in case they are + tagged with a VLAN that is not configured on the ingress bridge port + * - ``ingress_spanning_tree_filter`` + - ``drop`` + - Traps incoming packets that the device decided to drop in case the STP + state of the ingress bridge port is not "forwarding" + * - ``port_list_is_empty`` + - ``drop`` + - Traps packets that the device decided to drop in case they need to be + flooded (e.g., unknown unicast, unregistered multicast) and there are + no ports the packets should be flooded to + * - ``port_loopback_filter`` + - ``drop`` + - Traps packets that the device decided to drop in case after layer 2 + forwarding the only port from which they should be transmitted through + is the port from which they were received + * - ``blackhole_route`` + - ``drop`` + - Traps packets that the device decided to drop in case they hit a + blackhole route + * - ``ttl_value_is_too_small`` + - ``exception`` + - Traps unicast packets that should be forwarded by the device whose TTL + was decremented to 0 or less + * - ``tail_drop`` + - ``drop`` + - Traps packets that the device decided to drop because they could not be + enqueued to a transmission queue which is full + * - ``non_ip`` + - ``drop`` + - Traps packets that the device decided to drop because they need to + undergo a layer 3 lookup, but are not IP or MPLS packets + * - ``uc_dip_over_mc_dmac`` + - ``drop`` + - Traps packets that the device decided to drop because they need to be + routed and they have a unicast destination IP and a multicast destination + MAC + * - ``dip_is_loopback_address`` + - ``drop`` + - Traps packets that the device decided to drop because they need to be + routed and their destination IP is the loopback address (i.e., 127.0.0.0/8 + and ::1/128) + * - ``sip_is_mc`` + - ``drop`` + - Traps packets that the device decided to drop because they need to be + routed and their source IP is multicast (i.e., 224.0.0.0/8 and ff::/8) + * - ``sip_is_loopback_address`` + - ``drop`` + - Traps packets that the device decided to drop because they need to be + routed and their source IP is the loopback address (i.e., 127.0.0.0/8 and ::1/128) + * - ``ip_header_corrupted`` + - ``drop`` + - Traps packets that the device decided to drop because they need to be + routed and their IP header is corrupted: wrong checksum, wrong IP version + or too short Internet Header Length (IHL) + * - ``ipv4_sip_is_limited_bc`` + - ``drop`` + - Traps packets that the device decided to drop because they need to be + routed and their source IP is limited broadcast (i.e., 255.255.255.255/32) + * - ``ipv6_mc_dip_reserved_scope`` + - ``drop`` + - Traps IPv6 packets that the device decided to drop because they need to + be routed and their IPv6 multicast destination IP has a reserved scope + (i.e., ffx0::/16) + * - ``ipv6_mc_dip_interface_local_scope`` + - ``drop`` + - Traps IPv6 packets that the device decided to drop because they need to + be routed and their IPv6 multicast destination IP has an interface-local scope + (i.e., ffx1::/16) + * - ``mtu_value_is_too_small`` + - ``exception`` + - Traps packets that should have been routed by the device, but were bigger + than the MTU of the egress interface + * - ``unresolved_neigh`` + - ``exception`` + - Traps packets that did not have a matching IP neighbour after routing + * - ``mc_reverse_path_forwarding`` + - ``exception`` + - Traps multicast IP packets that failed reverse-path forwarding (RPF) + check during multicast routing + * - ``reject_route`` + - ``exception`` + - Traps packets that hit reject routes (i.e., "unreachable", "prohibit") + * - ``ipv4_lpm_miss`` + - ``exception`` + - Traps unicast IPv4 packets that did not match any route + * - ``ipv6_lpm_miss`` + - ``exception`` + - Traps unicast IPv6 packets that did not match any route + * - ``non_routable_packet`` + - ``drop`` + - Traps packets that the device decided to drop because they are not + supposed to be routed. For example, IGMP queries can be flooded by the + device in layer 2 and reach the router. Such packets should not be + routed and instead dropped + * - ``decap_error`` + - ``exception`` + - Traps NVE and IPinIP packets that the device decided to drop because of + failure during decapsulation (e.g., packet being too short, reserved + bits set in VXLAN header) + * - ``overlay_smac_is_mc`` + - ``drop`` + - Traps NVE packets that the device decided to drop because their overlay + source MAC is multicast + * - ``ingress_flow_action_drop`` + - ``drop`` + - Traps packets dropped during processing of ingress flow action drop + * - ``egress_flow_action_drop`` + - ``drop`` + - Traps packets dropped during processing of egress flow action drop + * - ``stp`` + - ``control`` + - Traps STP packets + * - ``lacp`` + - ``control`` + - Traps LACP packets + * - ``lldp`` + - ``control`` + - Traps LLDP packets + * - ``igmp_query`` + - ``control`` + - Traps IGMP Membership Query packets + * - ``igmp_v1_report`` + - ``control`` + - Traps IGMP Version 1 Membership Report packets + * - ``igmp_v2_report`` + - ``control`` + - Traps IGMP Version 2 Membership Report packets + * - ``igmp_v3_report`` + - ``control`` + - Traps IGMP Version 3 Membership Report packets + * - ``igmp_v2_leave`` + - ``control`` + - Traps IGMP Version 2 Leave Group packets + * - ``mld_query`` + - ``control`` + - Traps MLD Multicast Listener Query packets + * - ``mld_v1_report`` + - ``control`` + - Traps MLD Version 1 Multicast Listener Report packets + * - ``mld_v2_report`` + - ``control`` + - Traps MLD Version 2 Multicast Listener Report packets + * - ``mld_v1_done`` + - ``control`` + - Traps MLD Version 1 Multicast Listener Done packets + * - ``ipv4_dhcp`` + - ``control`` + - Traps IPv4 DHCP packets + * - ``ipv6_dhcp`` + - ``control`` + - Traps IPv6 DHCP packets + * - ``arp_request`` + - ``control`` + - Traps ARP request packets + * - ``arp_response`` + - ``control`` + - Traps ARP response packets + * - ``arp_overlay`` + - ``control`` + - Traps NVE-decapsulated ARP packets that reached the overlay network. + This is required, for example, when the address that needs to be + resolved is a local address + * - ``ipv6_neigh_solicit`` + - ``control`` + - Traps IPv6 Neighbour Solicitation packets + * - ``ipv6_neigh_advert`` + - ``control`` + - Traps IPv6 Neighbour Advertisement packets + * - ``ipv4_bfd`` + - ``control`` + - Traps IPv4 BFD packets + * - ``ipv6_bfd`` + - ``control`` + - Traps IPv6 BFD packets + * - ``ipv4_ospf`` + - ``control`` + - Traps IPv4 OSPF packets + * - ``ipv6_ospf`` + - ``control`` + - Traps IPv6 OSPF packets + * - ``ipv4_bgp`` + - ``control`` + - Traps IPv4 BGP packets + * - ``ipv6_bgp`` + - ``control`` + - Traps IPv6 BGP packets + * - ``ipv4_vrrp`` + - ``control`` + - Traps IPv4 VRRP packets + * - ``ipv6_vrrp`` + - ``control`` + - Traps IPv6 VRRP packets + * - ``ipv4_pim`` + - ``control`` + - Traps IPv4 PIM packets + * - ``ipv6_pim`` + - ``control`` + - Traps IPv6 PIM packets + * - ``uc_loopback`` + - ``control`` + - Traps unicast packets that need to be routed through the same layer 3 + interface from which they were received. Such packets are routed by the + kernel, but also cause it to potentially generate ICMP redirect packets + * - ``local_route`` + - ``control`` + - Traps unicast packets that hit a local route and need to be locally + delivered + * - ``external_route`` + - ``control`` + - Traps packets that should be routed through an external interface (e.g., + management interface) that does not belong to the same device (e.g., + switch ASIC) as the ingress interface + * - ``ipv6_uc_dip_link_local_scope`` + - ``control`` + - Traps unicast IPv6 packets that need to be routed and have a destination + IP address with a link-local scope (i.e., fe80::/10). The trap allows + device drivers to avoid programming link-local routes, but still receive + packets for local delivery + * - ``ipv6_dip_all_nodes`` + - ``control`` + - Traps IPv6 packets that their destination IP address is the "All Nodes + Address" (i.e., ff02::1) + * - ``ipv6_dip_all_routers`` + - ``control`` + - Traps IPv6 packets that their destination IP address is the "All Routers + Address" (i.e., ff02::2) + * - ``ipv6_router_solicit`` + - ``control`` + - Traps IPv6 Router Solicitation packets + * - ``ipv6_router_advert`` + - ``control`` + - Traps IPv6 Router Advertisement packets + * - ``ipv6_redirect`` + - ``control`` + - Traps IPv6 Redirect Message packets + * - ``ipv4_router_alert`` + - ``control`` + - Traps IPv4 packets that need to be routed and include the Router Alert + option. Such packets need to be locally delivered to raw sockets that + have the IP_ROUTER_ALERT socket option set + * - ``ipv6_router_alert`` + - ``control`` + - Traps IPv6 packets that need to be routed and include the Router Alert + option in their Hop-by-Hop extension header. Such packets need to be + locally delivered to raw sockets that have the IPV6_ROUTER_ALERT socket + option set + * - ``ptp_event`` + - ``control`` + - Traps PTP time-critical event messages (Sync, Delay_req, Pdelay_Req and + Pdelay_Resp) + * - ``ptp_general`` + - ``control`` + - Traps PTP general messages (Announce, Follow_Up, Delay_Resp, + Pdelay_Resp_Follow_Up, management and signaling) + * - ``flow_action_sample`` + - ``control`` + - Traps packets sampled during processing of flow action sample (e.g., via + tc's sample action) + * - ``flow_action_trap`` + - ``control`` + - Traps packets logged during processing of flow action trap (e.g., via + tc's trap action) + * - ``early_drop`` + - ``drop`` + - Traps packets dropped due to the RED (Random Early Detection) algorithm + (i.e., early drops) + * - ``vxlan_parsing`` + - ``drop`` + - Traps packets dropped due to an error in the VXLAN header parsing which + might be because of packet truncation or the I flag is not set. + * - ``llc_snap_parsing`` + - ``drop`` + - Traps packets dropped due to an error in the LLC+SNAP header parsing + * - ``vlan_parsing`` + - ``drop`` + - Traps packets dropped due to an error in the VLAN header parsing. Could + include unexpected packet truncation. + * - ``pppoe_ppp_parsing`` + - ``drop`` + - Traps packets dropped due to an error in the PPPoE+PPP header parsing. + This could include finding a session ID of 0xFFFF (which is reserved and + not for use), a PPPoE length which is larger than the frame received or + any common error on this type of header + * - ``mpls_parsing`` + - ``drop`` + - Traps packets dropped due to an error in the MPLS header parsing which + could include unexpected header truncation + * - ``arp_parsing`` + - ``drop`` + - Traps packets dropped due to an error in the ARP header parsing + * - ``ip_1_parsing`` + - ``drop`` + - Traps packets dropped due to an error in the first IP header parsing. + This packet trap could include packets which do not pass an IP checksum + check, a header length check (a minimum of 20 bytes), which might suffer + from packet truncation thus the total length field exceeds the received + packet length etc + * - ``ip_n_parsing`` + - ``drop`` + - Traps packets dropped due to an error in the parsing of the last IP + header (the inner one in case of an IP over IP tunnel). The same common + error checking is performed here as for the ip_1_parsing trap + * - ``gre_parsing`` + - ``drop`` + - Traps packets dropped due to an error in the GRE header parsing + * - ``udp_parsing`` + - ``drop`` + - Traps packets dropped due to an error in the UDP header parsing. + This packet trap could include checksum errorrs, an improper UDP + length detected (smaller than 8 bytes) or detection of header + truncation. + * - ``tcp_parsing`` + - ``drop`` + - Traps packets dropped due to an error in the TCP header parsing. + This could include TCP checksum errors, improper combination of SYN, FIN + and/or RESET etc. + * - ``ipsec_parsing`` + - ``drop`` + - Traps packets dropped due to an error in the IPSEC header parsing + * - ``sctp_parsing`` + - ``drop`` + - Traps packets dropped due to an error in the SCTP header parsing. + This would mean that port number 0 was used or that the header is + truncated. + * - ``dccp_parsing`` + - ``drop`` + - Traps packets dropped due to an error in the DCCP header parsing + * - ``gtp_parsing`` + - ``drop`` + - Traps packets dropped due to an error in the GTP header parsing + * - ``esp_parsing`` + - ``drop`` + - Traps packets dropped due to an error in the ESP header parsing + * - ``blackhole_nexthop`` + - ``drop`` + - Traps packets that the device decided to drop in case they hit a + blackhole nexthop + * - ``dmac_filter`` + - ``drop`` + - Traps incoming packets that the device decided to drop because + the destination MAC is not configured in the MAC table and + the interface is not in promiscuous mode + * - ``eapol`` + - ``control`` + - Traps "Extensible Authentication Protocol over LAN" (EAPOL) packets + specified in IEEE 802.1X + * - ``locked_port`` + - ``drop`` + - Traps packets that the device decided to drop because they failed the + locked bridge port check. That is, packets that were received via a + locked port and whose {SMAC, VID} does not correspond to an FDB entry + pointing to the port + +Driver-specific Packet Traps +============================ + +Device drivers can register driver-specific packet traps, but these must be +clearly documented. Such traps can correspond to device-specific exceptions and +help debug packet drops caused by these exceptions. The following list includes +links to the description of driver-specific traps registered by various device +drivers: + + * Documentation/networking/devlink/netdevsim.rst + * Documentation/networking/devlink/mlxsw.rst + * Documentation/networking/devlink/prestera.rst + +.. _Generic-Packet-Trap-Groups: + +Generic Packet Trap Groups +========================== + +Generic packet trap groups are used to aggregate logically related packet +traps. These groups allow the user to batch operations such as setting the trap +action of all member traps. In addition, ``devlink-trap`` can report aggregated +per-group packets and bytes statistics, in case per-trap statistics are too +narrow. The description of these groups must be added to the following table: + +.. list-table:: List of Generic Packet Trap Groups + :widths: 10 90 + + * - Name + - Description + * - ``l2_drops`` + - Contains packet traps for packets that were dropped by the device during + layer 2 forwarding (i.e., bridge) + * - ``l3_drops`` + - Contains packet traps for packets that were dropped by the device during + layer 3 forwarding + * - ``l3_exceptions`` + - Contains packet traps for packets that hit an exception (e.g., TTL + error) during layer 3 forwarding + * - ``buffer_drops`` + - Contains packet traps for packets that were dropped by the device due to + an enqueue decision + * - ``tunnel_drops`` + - Contains packet traps for packets that were dropped by the device during + tunnel encapsulation / decapsulation + * - ``acl_drops`` + - Contains packet traps for packets that were dropped by the device during + ACL processing + * - ``stp`` + - Contains packet traps for STP packets + * - ``lacp`` + - Contains packet traps for LACP packets + * - ``lldp`` + - Contains packet traps for LLDP packets + * - ``mc_snooping`` + - Contains packet traps for IGMP and MLD packets required for multicast + snooping + * - ``dhcp`` + - Contains packet traps for DHCP packets + * - ``neigh_discovery`` + - Contains packet traps for neighbour discovery packets (e.g., ARP, IPv6 + ND) + * - ``bfd`` + - Contains packet traps for BFD packets + * - ``ospf`` + - Contains packet traps for OSPF packets + * - ``bgp`` + - Contains packet traps for BGP packets + * - ``vrrp`` + - Contains packet traps for VRRP packets + * - ``pim`` + - Contains packet traps for PIM packets + * - ``uc_loopback`` + - Contains a packet trap for unicast loopback packets (i.e., + ``uc_loopback``). This trap is singled-out because in cases such as + one-armed router it will be constantly triggered. To limit the impact on + the CPU usage, a packet trap policer with a low rate can be bound to the + group without affecting other traps + * - ``local_delivery`` + - Contains packet traps for packets that should be locally delivered after + routing, but do not match more specific packet traps (e.g., + ``ipv4_bgp``) + * - ``external_delivery`` + - Contains packet traps for packets that should be routed through an + external interface (e.g., management interface) that does not belong to + the same device (e.g., switch ASIC) as the ingress interface + * - ``ipv6`` + - Contains packet traps for various IPv6 control packets (e.g., Router + Advertisements) + * - ``ptp_event`` + - Contains packet traps for PTP time-critical event messages (Sync, + Delay_req, Pdelay_Req and Pdelay_Resp) + * - ``ptp_general`` + - Contains packet traps for PTP general messages (Announce, Follow_Up, + Delay_Resp, Pdelay_Resp_Follow_Up, management and signaling) + * - ``acl_sample`` + - Contains packet traps for packets that were sampled by the device during + ACL processing + * - ``acl_trap`` + - Contains packet traps for packets that were trapped (logged) by the + device during ACL processing + * - ``parser_error_drops`` + - Contains packet traps for packets that were marked by the device during + parsing as erroneous + * - ``eapol`` + - Contains packet traps for "Extensible Authentication Protocol over LAN" + (EAPOL) packets specified in IEEE 802.1X + +Packet Trap Policers +==================== + +As previously explained, the underlying device can trap certain packets to the +CPU for processing. In most cases, the underlying device is capable of handling +packet rates that are several orders of magnitude higher compared to those that +can be handled by the CPU. + +Therefore, in order to prevent the underlying device from overwhelming the CPU, +devices usually include packet trap policers that are able to police the +trapped packets to rates that can be handled by the CPU. + +The ``devlink-trap`` mechanism allows capable device drivers to register their +supported packet trap policers with ``devlink``. The device driver can choose +to associate these policers with supported packet trap groups (see +:ref:`Generic-Packet-Trap-Groups`) during its initialization, thereby exposing +its default control plane policy to user space. + +Device drivers should allow user space to change the parameters of the policers +(e.g., rate, burst size) as well as the association between the policers and +trap groups by implementing the relevant callbacks. + +If possible, device drivers should implement a callback that allows user space +to retrieve the number of packets that were dropped by the policer because its +configured policy was violated. + +Testing +======= + +See ``tools/testing/selftests/drivers/net/netdevsim/devlink_trap.sh`` for a +test covering the core infrastructure. Test cases should be added for any new +functionality. + +Device drivers should focus their tests on device-specific functionality, such +as the triggering of supported packet traps. diff --git a/Documentation/networking/devlink/etas_es58x.rst b/Documentation/networking/devlink/etas_es58x.rst new file mode 100644 index 0000000000..3b857d82a4 --- /dev/null +++ b/Documentation/networking/devlink/etas_es58x.rst @@ -0,0 +1,36 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================== +etas_es58x devlink support +========================== + +This document describes the devlink features implemented by the +``etas_es58x`` device driver. + +Info versions +============= + +The ``etas_es58x`` driver reports the following versions + +.. list-table:: devlink info versions implemented + :widths: 5 5 90 + + * - Name + - Type + - Description + * - ``fw`` + - running + - Version of the firmware running on the device. Also available + through ``ethtool -i`` as the first member of the + ``firmware-version``. + * - ``fw.bootloader`` + - running + - Version of the bootloader running on the device. Also available + through ``ethtool -i`` as the second member of the + ``firmware-version``. + * - ``board.rev`` + - fixed + - The hardware revision of the device. + * - ``serial_number`` + - fixed + - The USB serial number. Also available through ``lsusb -v``. diff --git a/Documentation/networking/devlink/hns3.rst b/Documentation/networking/devlink/hns3.rst new file mode 100644 index 0000000000..4562a6e478 --- /dev/null +++ b/Documentation/networking/devlink/hns3.rst @@ -0,0 +1,25 @@ +.. SPDX-License-Identifier: GPL-2.0 + +==================== +hns3 devlink support +==================== + +This document describes the devlink features implemented by the ``hns3`` +device driver. + +The ``hns3`` driver supports reloading via ``DEVLINK_CMD_RELOAD``. + +Info versions +============= + +The ``hns3`` driver reports the following versions + +.. list-table:: devlink info versions implemented + :widths: 10 10 80 + + * - Name + - Type + - Description + * - ``fw`` + - running + - Used to represent the firmware version. diff --git a/Documentation/networking/devlink/ice.rst b/Documentation/networking/devlink/ice.rst new file mode 100644 index 0000000000..2f60e34ab9 --- /dev/null +++ b/Documentation/networking/devlink/ice.rst @@ -0,0 +1,395 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=================== +ice devlink support +=================== + +This document describes the devlink features implemented by the ``ice`` +device driver. + +Parameters +========== + +.. list-table:: Generic parameters implemented + + * - Name + - Mode + - Notes + * - ``enable_roce`` + - runtime + - mutually exclusive with ``enable_iwarp`` + * - ``enable_iwarp`` + - runtime + - mutually exclusive with ``enable_roce`` + +Info versions +============= + +The ``ice`` driver reports the following versions + +.. list-table:: devlink info versions implemented + :widths: 5 5 5 90 + + * - Name + - Type + - Example + - Description + * - ``board.id`` + - fixed + - K65390-000 + - The Product Board Assembly (PBA) identifier of the board. + * - ``fw.mgmt`` + - running + - 2.1.7 + - 3-digit version number of the management firmware running on the + Embedded Management Processor of the device. It controls the PHY, + link, access to device resources, etc. Intel documentation refers to + this as the EMP firmware. + * - ``fw.mgmt.api`` + - running + - 1.5.1 + - 3-digit version number (major.minor.patch) of the API exported over + the AdminQ by the management firmware. Used by the driver to + identify what commands are supported. Historical versions of the + kernel only displayed a 2-digit version number (major.minor). + * - ``fw.mgmt.build`` + - running + - 0x305d955f + - Unique identifier of the source for the management firmware. + * - ``fw.undi`` + - running + - 1.2581.0 + - Version of the Option ROM containing the UEFI driver. The version is + reported in ``major.minor.patch`` format. The major version is + incremented whenever a major breaking change occurs, or when the + minor version would overflow. The minor version is incremented for + non-breaking changes and reset to 1 when the major version is + incremented. The patch version is normally 0 but is incremented when + a fix is delivered as a patch against an older base Option ROM. + * - ``fw.psid.api`` + - running + - 0.80 + - Version defining the format of the flash contents. + * - ``fw.bundle_id`` + - running + - 0x80002ec0 + - Unique identifier of the firmware image file that was loaded onto + the device. Also referred to as the EETRACK identifier of the NVM. + * - ``fw.app.name`` + - running + - ICE OS Default Package + - The name of the DDP package that is active in the device. The DDP + package is loaded by the driver during initialization. Each + variation of the DDP package has a unique name. + * - ``fw.app`` + - running + - 1.3.1.0 + - The version of the DDP package that is active in the device. Note + that both the name (as reported by ``fw.app.name``) and version are + required to uniquely identify the package. + * - ``fw.app.bundle_id`` + - running + - 0xc0000001 + - Unique identifier for the DDP package loaded in the device. Also + referred to as the DDP Track ID. Can be used to uniquely identify + the specific DDP package. + * - ``fw.netlist`` + - running + - 1.1.2000-6.7.0 + - The version of the netlist module. This module defines the device's + Ethernet capabilities and default settings, and is used by the + management firmware as part of managing link and device + connectivity. + * - ``fw.netlist.build`` + - running + - 0xee16ced7 + - The first 4 bytes of the hash of the netlist module contents. + +Flash Update +============ + +The ``ice`` driver implements support for flash update using the +``devlink-flash`` interface. It supports updating the device flash using a +combined flash image that contains the ``fw.mgmt``, ``fw.undi``, and +``fw.netlist`` components. + +.. list-table:: List of supported overwrite modes + :widths: 5 95 + + * - Bits + - Behavior + * - ``DEVLINK_FLASH_OVERWRITE_SETTINGS`` + - Do not preserve settings stored in the flash components being + updated. This includes overwriting the port configuration that + determines the number of physical functions the device will + initialize with. + * - ``DEVLINK_FLASH_OVERWRITE_SETTINGS`` and ``DEVLINK_FLASH_OVERWRITE_IDENTIFIERS`` + - Do not preserve either settings or identifiers. Overwrite everything + in the flash with the contents from the provided image, without + performing any preservation. This includes overwriting device + identifying fields such as the MAC address, VPD area, and device + serial number. It is expected that this combination be used with an + image customized for the specific device. + +The ice hardware does not support overwriting only identifiers while +preserving settings, and thus ``DEVLINK_FLASH_OVERWRITE_IDENTIFIERS`` on its +own will be rejected. If no overwrite mask is provided, the firmware will be +instructed to preserve all settings and identifying fields when updating. + +Reload +====== + +The ``ice`` driver supports activating new firmware after a flash update +using ``DEVLINK_CMD_RELOAD`` with the ``DEVLINK_RELOAD_ACTION_FW_ACTIVATE`` +action. + +.. code:: shell + + $ devlink dev reload pci/0000:01:00.0 reload action fw_activate + +The new firmware is activated by issuing a device specific Embedded +Management Processor reset which requests the device to reset and reload the +EMP firmware image. + +The driver does not currently support reloading the driver via +``DEVLINK_RELOAD_ACTION_DRIVER_REINIT``. + +Port split +========== + +The ``ice`` driver supports port splitting only for port 0, as the FW has +a predefined set of available port split options for the whole device. + +A system reboot is required for port split to be applied. + +The following command will select the port split option with 4 ports: + +.. code:: shell + + $ devlink port split pci/0000:16:00.0/0 count 4 + +The list of all available port options will be printed to dynamic debug after +each ``split`` and ``unsplit`` command. The first option is the default. + +.. code:: shell + + ice 0000:16:00.0: Available port split options and max port speeds (Gbps): + ice 0000:16:00.0: Status Split Quad 0 Quad 1 + ice 0000:16:00.0: count L0 L1 L2 L3 L4 L5 L6 L7 + ice 0000:16:00.0: Active 2 100 - - - 100 - - - + ice 0000:16:00.0: 2 50 - 50 - - - - - + ice 0000:16:00.0: Pending 4 25 25 25 25 - - - - + ice 0000:16:00.0: 4 25 25 - - 25 25 - - + ice 0000:16:00.0: 8 10 10 10 10 10 10 10 10 + ice 0000:16:00.0: 1 100 - - - - - - - + +There could be multiple FW port options with the same port split count. When +the same port split count request is issued again, the next FW port option with +the same port split count will be selected. + +``devlink port unsplit`` will select the option with a split count of 1. If +there is no FW option available with split count 1, you will receive an error. + +Regions +======= + +The ``ice`` driver implements the following regions for accessing internal +device data. + +.. list-table:: regions implemented + :widths: 15 85 + + * - Name + - Description + * - ``nvm-flash`` + - The contents of the entire flash chip, sometimes referred to as + the device's Non Volatile Memory. + * - ``shadow-ram`` + - The contents of the Shadow RAM, which is loaded from the beginning + of the flash. Although the contents are primarily from the flash, + this area also contains data generated during device boot which is + not stored in flash. + * - ``device-caps`` + - The contents of the device firmware's capabilities buffer. Useful to + determine the current state and configuration of the device. + +Both the ``nvm-flash`` and ``shadow-ram`` regions can be accessed without a +snapshot. The ``device-caps`` region requires a snapshot as the contents are +sent by firmware and can't be split into separate reads. + +Users can request an immediate capture of a snapshot for all three regions +via the ``DEVLINK_CMD_REGION_NEW`` command. + +.. code:: shell + + $ devlink region show + pci/0000:01:00.0/nvm-flash: size 10485760 snapshot [] max 1 + pci/0000:01:00.0/device-caps: size 4096 snapshot [] max 10 + + $ devlink region new pci/0000:01:00.0/nvm-flash snapshot 1 + $ devlink region dump pci/0000:01:00.0/nvm-flash snapshot 1 + + $ devlink region dump pci/0000:01:00.0/nvm-flash snapshot 1 + 0000000000000000 0014 95dc 0014 9514 0035 1670 0034 db30 + 0000000000000010 0000 0000 ffff ff04 0029 8c00 0028 8cc8 + 0000000000000020 0016 0bb8 0016 1720 0000 0000 c00f 3ffc + 0000000000000030 bada cce5 bada cce5 bada cce5 bada cce5 + + $ devlink region read pci/0000:01:00.0/nvm-flash snapshot 1 address 0 length 16 + 0000000000000000 0014 95dc 0014 9514 0035 1670 0034 db30 + + $ devlink region delete pci/0000:01:00.0/nvm-flash snapshot 1 + + $ devlink region new pci/0000:01:00.0/device-caps snapshot 1 + $ devlink region dump pci/0000:01:00.0/device-caps snapshot 1 + 0000000000000000 01 00 01 00 00 00 00 00 01 00 00 00 00 00 00 00 + 0000000000000010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + 0000000000000020 02 00 02 01 32 03 00 00 0a 00 00 00 25 00 00 00 + 0000000000000030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + 0000000000000040 04 00 01 00 01 00 00 00 00 00 00 00 00 00 00 00 + 0000000000000050 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + 0000000000000060 05 00 01 00 03 00 00 00 00 00 00 00 00 00 00 00 + 0000000000000070 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + 0000000000000080 06 00 01 00 01 00 00 00 00 00 00 00 00 00 00 00 + 0000000000000090 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + 00000000000000a0 08 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00 + 00000000000000b0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + 00000000000000c0 12 00 01 00 01 00 00 00 01 00 01 00 00 00 00 00 + 00000000000000d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + 00000000000000e0 13 00 01 00 00 01 00 00 00 00 00 00 00 00 00 00 + 00000000000000f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + 0000000000000100 14 00 01 00 01 00 00 00 00 00 00 00 00 00 00 00 + 0000000000000110 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + 0000000000000120 15 00 01 00 01 00 00 00 00 00 00 00 00 00 00 00 + 0000000000000130 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + 0000000000000140 16 00 01 00 01 00 00 00 00 00 00 00 00 00 00 00 + 0000000000000150 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + 0000000000000160 17 00 01 00 06 00 00 00 00 00 00 00 00 00 00 00 + 0000000000000170 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + 0000000000000180 18 00 01 00 01 00 00 00 01 00 00 00 08 00 00 00 + 0000000000000190 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + 00000000000001a0 22 00 01 00 01 00 00 00 00 00 00 00 00 00 00 00 + 00000000000001b0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + 00000000000001c0 40 00 01 00 00 08 00 00 08 00 00 00 00 00 00 00 + 00000000000001d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + 00000000000001e0 41 00 01 00 00 08 00 00 00 00 00 00 00 00 00 00 + 00000000000001f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + 0000000000000200 42 00 01 00 00 08 00 00 00 00 00 00 00 00 00 00 + 0000000000000210 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + + $ devlink region delete pci/0000:01:00.0/device-caps snapshot 1 + +Devlink Rate +============ + +The ``ice`` driver implements devlink-rate API. It allows for offload of +the Hierarchical QoS to the hardware. It enables user to group Virtual +Functions in a tree structure and assign supported parameters: tx_share, +tx_max, tx_priority and tx_weight to each node in a tree. So effectively +user gains an ability to control how much bandwidth is allocated for each +VF group. This is later enforced by the HW. + +It is assumed that this feature is mutually exclusive with DCB performed +in FW and ADQ, or any driver feature that would trigger changes in QoS, +for example creation of the new traffic class. The driver will prevent DCB +or ADQ configuration if user started making any changes to the nodes using +devlink-rate API. To configure those features a driver reload is necessary. +Correspondingly if ADQ or DCB will get configured the driver won't export +hierarchy at all, or will remove the untouched hierarchy if those +features are enabled after the hierarchy is exported, but before any +changes are made. + +This feature is also dependent on switchdev being enabled in the system. +It's required because devlink-rate requires devlink-port objects to be +present, and those objects are only created in switchdev mode. + +If the driver is set to the switchdev mode, it will export internal +hierarchy the moment VF's are created. Root of the tree is always +represented by the node_0. This node can't be deleted by the user. Leaf +nodes and nodes with children also can't be deleted. + +.. list-table:: Attributes supported + :widths: 15 85 + + * - Name + - Description + * - ``tx_max`` + - maximum bandwidth to be consumed by the tree Node. Rate Limit is + an absolute number specifying a maximum amount of bytes a Node may + consume during the course of one second. Rate limit guarantees + that a link will not oversaturate the receiver on the remote end + and also enforces an SLA between the subscriber and network + provider. + * - ``tx_share`` + - minimum bandwidth allocated to a tree node when it is not blocked. + It specifies an absolute BW. While tx_max defines the maximum + bandwidth the node may consume, the tx_share marks committed BW + for the Node. + * - ``tx_priority`` + - allows for usage of strict priority arbiter among siblings. This + arbitration scheme attempts to schedule nodes based on their + priority as long as the nodes remain within their bandwidth limit. + Range 0-7. Nodes with priority 7 have the highest priority and are + selected first, while nodes with priority 0 have the lowest + priority. Nodes that have the same priority are treated equally. + * - ``tx_weight`` + - allows for usage of Weighted Fair Queuing arbitration scheme among + siblings. This arbitration scheme can be used simultaneously with + the strict priority. Range 1-200. Only relative values matter for + arbitration. + +``tx_priority`` and ``tx_weight`` can be used simultaneously. In that case +nodes with the same priority form a WFQ subgroup in the sibling group +and arbitration among them is based on assigned weights. + +.. code:: shell + + # enable switchdev + $ devlink dev eswitch set pci/0000:4b:00.0 mode switchdev + + # at this point driver should export internal hierarchy + $ echo 2 > /sys/class/net/ens785np0/device/sriov_numvfs + + $ devlink port function rate show + pci/0000:4b:00.0/node_25: type node parent node_24 + pci/0000:4b:00.0/node_24: type node parent node_0 + pci/0000:4b:00.0/node_32: type node parent node_31 + pci/0000:4b:00.0/node_31: type node parent node_30 + pci/0000:4b:00.0/node_30: type node parent node_16 + pci/0000:4b:00.0/node_19: type node parent node_18 + pci/0000:4b:00.0/node_18: type node parent node_17 + pci/0000:4b:00.0/node_17: type node parent node_16 + pci/0000:4b:00.0/node_14: type node parent node_5 + pci/0000:4b:00.0/node_5: type node parent node_3 + pci/0000:4b:00.0/node_13: type node parent node_4 + pci/0000:4b:00.0/node_12: type node parent node_4 + pci/0000:4b:00.0/node_11: type node parent node_4 + pci/0000:4b:00.0/node_10: type node parent node_4 + pci/0000:4b:00.0/node_9: type node parent node_4 + pci/0000:4b:00.0/node_8: type node parent node_4 + pci/0000:4b:00.0/node_7: type node parent node_4 + pci/0000:4b:00.0/node_6: type node parent node_4 + pci/0000:4b:00.0/node_4: type node parent node_3 + pci/0000:4b:00.0/node_3: type node parent node_16 + pci/0000:4b:00.0/node_16: type node parent node_15 + pci/0000:4b:00.0/node_15: type node parent node_0 + pci/0000:4b:00.0/node_2: type node parent node_1 + pci/0000:4b:00.0/node_1: type node parent node_0 + pci/0000:4b:00.0/node_0: type node + pci/0000:4b:00.0/1: type leaf parent node_25 + pci/0000:4b:00.0/2: type leaf parent node_25 + + # let's create some custom node + $ devlink port function rate add pci/0000:4b:00.0/node_custom parent node_0 + + # second custom node + $ devlink port function rate add pci/0000:4b:00.0/node_custom_1 parent node_custom + + # reassign second VF to newly created branch + $ devlink port function rate set pci/0000:4b:00.0/2 parent node_custom_1 + + # assign tx_weight to the VF + $ devlink port function rate set pci/0000:4b:00.0/2 tx_weight 5 + + # assign tx_share to the VF + $ devlink port function rate set pci/0000:4b:00.0/2 tx_share 500Mbps diff --git a/Documentation/networking/devlink/index.rst b/Documentation/networking/devlink/index.rst new file mode 100644 index 0000000000..b49749e2b9 --- /dev/null +++ b/Documentation/networking/devlink/index.rst @@ -0,0 +1,69 @@ +Linux Devlink Documentation +=========================== + +devlink is an API to expose device information and resources not directly +related to any device class, such as chip-wide/switch-ASIC-wide configuration. + +Locking +------- + +Driver facing APIs are currently transitioning to allow more explicit +locking. Drivers can use the existing ``devlink_*`` set of APIs, or +new APIs prefixed by ``devl_*``. The older APIs handle all the locking +in devlink core, but don't allow registration of most sub-objects once +the main devlink object is itself registered. The newer ``devl_*`` APIs assume +the devlink instance lock is already held. Drivers can take the instance +lock by calling ``devl_lock()``. It is also held all callbacks of devlink +netlink commands. + +Drivers are encouraged to use the devlink instance lock for their own needs. + +Interface documentation +----------------------- + +The following pages describe various interfaces available through devlink in +general. + +.. toctree:: + :maxdepth: 1 + + devlink-dpipe + devlink-health + devlink-info + devlink-flash + devlink-params + devlink-port + devlink-region + devlink-resource + devlink-reload + devlink-selftests + devlink-trap + devlink-linecard + +Driver-specific documentation +----------------------------- + +Each driver that implements ``devlink`` is expected to document what +parameters, info versions, and other features it supports. + +.. toctree:: + :maxdepth: 1 + + bnxt + etas_es58x + hns3 + ionic + ice + mlx4 + mlx5 + mlxsw + mv88e6xxx + netdevsim + nfp + qed + ti-cpsw-switch + am65-nuss-cpsw-switch + prestera + iosm + octeontx2 + sfc diff --git a/Documentation/networking/devlink/ionic.rst b/Documentation/networking/devlink/ionic.rst new file mode 100644 index 0000000000..48da9c92d5 --- /dev/null +++ b/Documentation/networking/devlink/ionic.rst @@ -0,0 +1,29 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================== +ionic devlink support +===================== + +This document describes the devlink features implemented by the ``ionic`` +device driver. + +Info versions +============= + +The ``ionic`` driver reports the following versions + +.. list-table:: devlink info versions implemented + :widths: 5 5 90 + + * - Name + - Type + - Description + * - ``fw`` + - running + - Version of firmware running on the device + * - ``asic.id`` + - fixed + - The ASIC type for this device + * - ``asic.rev`` + - fixed + - The revision of the ASIC for this device diff --git a/Documentation/networking/devlink/iosm.rst b/Documentation/networking/devlink/iosm.rst new file mode 100644 index 0000000000..6136181339 --- /dev/null +++ b/Documentation/networking/devlink/iosm.rst @@ -0,0 +1,162 @@ +.. SPDX-License-Identifier: GPL-2.0 + +==================== +iosm devlink support +==================== + +This document describes the devlink features implemented by the ``iosm`` +device driver. + +Parameters +========== + +The ``iosm`` driver implements the following driver-specific parameters. + +.. list-table:: Driver-specific parameters implemented + :widths: 5 5 5 85 + + * - Name + - Type + - Mode + - Description + * - ``erase_full_flash`` + - u8 + - runtime + - erase_full_flash parameter is used to check if full erase is required for + the device during firmware flashing. + If set, Full nand erase command will be sent to the device. By default, + only conditional erase support is enabled. + + +Flash Update +============ + +The ``iosm`` driver implements support for flash update using the +``devlink-flash`` interface. + +It supports updating the device flash using a combined flash image which contains +the Bootloader images and other modem software images. + +The driver uses DEVLINK_SUPPORT_FLASH_UPDATE_COMPONENT to identify type of +firmware image that need to be flashed as requested by user space application. +Supported firmware image types. + +.. list-table:: Firmware Image types + :widths: 15 85 + + * - Name + - Description + * - ``PSI RAM`` + - Primary Signed Image + * - ``EBL`` + - External Bootloader + * - ``FLS`` + - Modem Software Image + +PSI RAM and EBL are the RAM images which are injected to the device when the +device is in BOOT ROM stage. Once this is successful, the actual modem firmware +image is flashed to the device. The modem software image contains multiple files +each having one secure bin file and at least one Loadmap/Region file. For flashing +these files, appropriate commands are sent to the modem device along with the +data required for flashing. The data like region count and address of each region +has to be passed to the driver using the devlink param command. + +If the device has to be fully erased before firmware flashing, user application +need to set the erase_full_flash parameter using devlink param command. +By default, conditional erase feature is supported. + +Flash Commands: +=============== +1) When modem is in Boot ROM stage, user can use below command to inject PSI RAM +image using devlink flash command. + +$ devlink dev flash pci/0000:02:00.0 file <PSI_RAM_File_name> + +2) If user want to do a full erase, below command need to be issued to set the +erase full flash param (To be set only if full erase required). + +$ devlink dev param set pci/0000:02:00.0 name erase_full_flash value true cmode runtime + +3) Inject EBL after the modem is in PSI stage. + +$ devlink dev flash pci/0000:02:00.0 file <EBL_File_name> + +4) Once EBL is injected successfully, then the actual firmware flashing takes +place. Below is the sequence of commands used for each of the firmware images. + +a) Flash secure bin file. + +$ devlink dev flash pci/0000:02:00.0 file <Secure_bin_file_name> + +b) Flashing the Loadmap/Region file + +$ devlink dev flash pci/0000:02:00.0 file <Load_map_file_name> + +Regions +======= + +The ``iosm`` driver supports dumping the coredump logs. + +In case a firmware encounters an exception, a snapshot will be taken by the +driver. Following regions are accessed for device internal data. + +.. list-table:: Regions implemented + :widths: 15 85 + + * - Name + - Description + * - ``report.json`` + - The summary of exception details logged as part of this region. + * - ``coredump.fcd`` + - This region contains the details related to the exception occurred in the + device (RAM dump). + * - ``cdd.log`` + - This region contains the logs related to the modem CDD driver. + * - ``eeprom.bin`` + - This region contains the eeprom logs. + * - ``bootcore_trace.bin`` + - This region contains the current instance of bootloader logs. + * - ``bootcore_prev_trace.bin`` + - This region contains the previous instance of bootloader logs. + + +Region commands +=============== + +$ devlink region show + +$ devlink region new pci/0000:02:00.0/report.json + +$ devlink region dump pci/0000:02:00.0/report.json snapshot 0 + +$ devlink region del pci/0000:02:00.0/report.json snapshot 0 + +$ devlink region new pci/0000:02:00.0/coredump.fcd + +$ devlink region dump pci/0000:02:00.0/coredump.fcd snapshot 1 + +$ devlink region del pci/0000:02:00.0/coredump.fcd snapshot 1 + +$ devlink region new pci/0000:02:00.0/cdd.log + +$ devlink region dump pci/0000:02:00.0/cdd.log snapshot 2 + +$ devlink region del pci/0000:02:00.0/cdd.log snapshot 2 + +$ devlink region new pci/0000:02:00.0/eeprom.bin + +$ devlink region dump pci/0000:02:00.0/eeprom.bin snapshot 3 + +$ devlink region del pci/0000:02:00.0/eeprom.bin snapshot 3 + +$ devlink region new pci/0000:02:00.0/bootcore_trace.bin + +$ devlink region dump pci/0000:02:00.0/bootcore_trace.bin snapshot 4 + +$ devlink region del pci/0000:02:00.0/bootcore_trace.bin snapshot 4 + +$ devlink region new pci/0000:02:00.0/bootcore_prev_trace.bin + +$ devlink region dump pci/0000:02:00.0/bootcore_prev_trace.bin snapshot 5 + +$ devlink region del pci/0000:02:00.0/bootcore_prev_trace.bin snapshot 5 diff --git a/Documentation/networking/devlink/mlx4.rst b/Documentation/networking/devlink/mlx4.rst new file mode 100644 index 0000000000..7b2d17ea54 --- /dev/null +++ b/Documentation/networking/devlink/mlx4.rst @@ -0,0 +1,56 @@ +.. SPDX-License-Identifier: GPL-2.0 + +==================== +mlx4 devlink support +==================== + +This document describes the devlink features implemented by the ``mlx4`` +device driver. + +Parameters +========== + +.. list-table:: Generic parameters implemented + + * - Name + - Mode + * - ``internal_err_reset`` + - driverinit, runtime + * - ``max_macs`` + - driverinit + * - ``region_snapshot_enable`` + - driverinit, runtime + +The ``mlx4`` driver also implements the following driver-specific +parameters. + +.. list-table:: Driver-specific parameters implemented + :widths: 5 5 5 85 + + * - Name + - Type + - Mode + - Description + * - ``enable_64b_cqe_eqe`` + - Boolean + - driverinit + - Enable 64 byte CQEs/EQEs, if the FW supports it. + * - ``enable_4k_uar`` + - Boolean + - driverinit + - Enable using the 4k UAR. + +The ``mlx4`` driver supports reloading via ``DEVLINK_CMD_RELOAD`` + +Regions +======= + +The ``mlx4`` driver supports dumping the firmware PCI crspace and health +buffer during a critical firmware issue. + +In case a firmware command times out, firmware getting stuck, or a non zero +value on the catastrophic buffer, a snapshot will be taken by the driver. + +The ``cr-space`` region will contain the firmware PCI crspace contents. The +``fw-health`` region will contain the device firmware's health buffer. +Snapshots for both of these regions are taken on the same event triggers. diff --git a/Documentation/networking/devlink/mlx5.rst b/Documentation/networking/devlink/mlx5.rst new file mode 100644 index 0000000000..702f204a3d --- /dev/null +++ b/Documentation/networking/devlink/mlx5.rst @@ -0,0 +1,288 @@ +.. SPDX-License-Identifier: GPL-2.0 + +==================== +mlx5 devlink support +==================== + +This document describes the devlink features implemented by the ``mlx5`` +device driver. + +Parameters +========== + +.. list-table:: Generic parameters implemented + + * - Name + - Mode + - Validation + * - ``enable_roce`` + - driverinit + - Type: Boolean + + If the device supports RoCE disablement, RoCE enablement state controls + device support for RoCE capability. Otherwise, the control occurs in the + driver stack. When RoCE is disabled at the driver level, only raw + ethernet QPs are supported. + * - ``io_eq_size`` + - driverinit + - The range is between 64 and 4096. + * - ``event_eq_size`` + - driverinit + - The range is between 64 and 4096. + * - ``max_macs`` + - driverinit + - The range is between 1 and 2^31. Only power of 2 values are supported. + +The ``mlx5`` driver also implements the following driver-specific +parameters. + +.. list-table:: Driver-specific parameters implemented + :widths: 5 5 5 85 + + * - Name + - Type + - Mode + - Description + * - ``flow_steering_mode`` + - string + - runtime + - Controls the flow steering mode of the driver + + * ``dmfs`` Device managed flow steering. In DMFS mode, the HW + steering entities are created and managed through firmware. + * ``smfs`` Software managed flow steering. In SMFS mode, the HW + steering entities are created and manage through the driver without + firmware intervention. + + SMFS mode is faster and provides better rule insertion rate compared to + default DMFS mode. + * - ``fdb_large_groups`` + - u32 + - driverinit + - Control the number of large groups (size > 1) in the FDB table. + + * The default value is 15, and the range is between 1 and 1024. + * - ``esw_multiport`` + - Boolean + - runtime + - Control MultiPort E-Switch shared fdb mode. + + An experimental mode where a single E-Switch is used and all the vports + and physical ports on the NIC are connected to it. + + An example is to send traffic from a VF that is created on PF0 to an + uplink that is natively associated with the uplink of PF1 + + Note: Future devices, ConnectX-8 and onward, will eventually have this + as the default to allow forwarding between all NIC ports in a single + E-switch environment and the dual E-switch mode will likely get + deprecated. + + Default: disabled + * - ``esw_port_metadata`` + - Boolean + - runtime + - When applicable, disabling eswitch metadata can increase packet rate up + to 20% depending on the use case and packet sizes. + + Eswitch port metadata state controls whether to internally tag packets + with metadata. Metadata tagging must be enabled for multi-port RoCE, + failover between representors and stacked devices. By default metadata is + enabled on the supported devices in E-switch. Metadata is applicable only + for E-switch in switchdev mode and users may disable it when NONE of the + below use cases will be in use: + 1. HCA is in Dual/multi-port RoCE mode. + 2. VF/SF representor bonding (Usually used for Live migration) + 3. Stacked devices + + When metadata is disabled, the above use cases will fail to initialize if + users try to enable them. + * - ``hairpin_num_queues`` + - u32 + - driverinit + - We refer to a TC NIC rule that involves forwarding as "hairpin". + Hairpin queues are mlx5 hardware specific implementation for hardware + forwarding of such packets. + + Control the number of hairpin queues. + * - ``hairpin_queue_size`` + - u32 + - driverinit + - Control the size (in packets) of the hairpin queues. + +The ``mlx5`` driver supports reloading via ``DEVLINK_CMD_RELOAD`` + +Info versions +============= + +The ``mlx5`` driver reports the following versions + +.. list-table:: devlink info versions implemented + :widths: 5 5 90 + + * - Name + - Type + - Description + * - ``fw.psid`` + - fixed + - Used to represent the board id of the device. + * - ``fw.version`` + - stored, running + - Three digit major.minor.subminor firmware version number. + +Health reporters +================ + +tx reporter +----------- +The tx reporter is responsible for reporting and recovering of the following three error scenarios: + +- tx timeout + Report on kernel tx timeout detection. + Recover by searching lost interrupts. +- tx error completion + Report on error tx completion. + Recover by flushing the tx queue and reset it. +- tx PTP port timestamping CQ unhealthy + Report too many CQEs never delivered on port ts CQ. + Recover by flushing and re-creating all PTP channels. + +tx reporter also support on demand diagnose callback, on which it provides +real time information of its send queues status. + +User commands examples: + +- Diagnose send queues status:: + + $ devlink health diagnose pci/0000:82:00.0 reporter tx + +.. note:: + This command has valid output only when interface is up, otherwise the command has empty output. + +- Show number of tx errors indicated, number of recover flows ended successfully, + is autorecover enabled and graceful period from last recover:: + + $ devlink health show pci/0000:82:00.0 reporter tx + +rx reporter +----------- +The rx reporter is responsible for reporting and recovering of the following two error scenarios: + +- rx queues' initialization (population) timeout + Population of rx queues' descriptors on ring initialization is done + in napi context via triggering an irq. In case of a failure to get + the minimum amount of descriptors, a timeout would occur, and + descriptors could be recovered by polling the EQ (Event Queue). +- rx completions with errors (reported by HW on interrupt context) + Report on rx completion error. + Recover (if needed) by flushing the related queue and reset it. + +rx reporter also supports on demand diagnose callback, on which it +provides real time information of its receive queues' status. + +- Diagnose rx queues' status and corresponding completion queue:: + + $ devlink health diagnose pci/0000:82:00.0 reporter rx + +.. note:: + This command has valid output only when interface is up. Otherwise, the command has empty output. + +- Show number of rx errors indicated, number of recover flows ended successfully, + is autorecover enabled, and graceful period from last recover:: + + $ devlink health show pci/0000:82:00.0 reporter rx + +fw reporter +----------- +The fw reporter implements `diagnose` and `dump` callbacks. +It follows symptoms of fw error such as fw syndrome by triggering +fw core dump and storing it into the dump buffer. +The fw reporter diagnose command can be triggered any time by the user to check +current fw status. + +User commands examples: + +- Check fw heath status:: + + $ devlink health diagnose pci/0000:82:00.0 reporter fw + +- Read FW core dump if already stored or trigger new one:: + + $ devlink health dump show pci/0000:82:00.0 reporter fw + +.. note:: + This command can run only on the PF which has fw tracer ownership, + running it on other PF or any VF will return "Operation not permitted". + +fw fatal reporter +----------------- +The fw fatal reporter implements `dump` and `recover` callbacks. +It follows fatal errors indications by CR-space dump and recover flow. +The CR-space dump uses vsc interface which is valid even if the FW command +interface is not functional, which is the case in most FW fatal errors. +The recover function runs recover flow which reloads the driver and triggers fw +reset if needed. +On firmware error, the health buffer is dumped into the dmesg. The log +level is derived from the error's severity (given in health buffer). + +User commands examples: + +- Run fw recover flow manually:: + + $ devlink health recover pci/0000:82:00.0 reporter fw_fatal + +- Read FW CR-space dump if already stored or trigger new one:: + + $ devlink health dump show pci/0000:82:00.1 reporter fw_fatal + +.. note:: + This command can run only on PF. + +vnic reporter +------------- +The vnic reporter implements only the `diagnose` callback. +It is responsible for querying the vnic diagnostic counters from fw and displaying +them in realtime. + +Description of the vnic counters: + +- total_q_under_processor_handle + number of queues in an error state due to + an async error or errored command. +- send_queue_priority_update_flow + number of QP/SQ priority/SL update events. +- cq_overrun + number of times CQ entered an error state due to an overflow. +- async_eq_overrun + number of times an EQ mapped to async events was overrun. + comp_eq_overrun number of times an EQ mapped to completion events was + overrun. +- quota_exceeded_command + number of commands issued and failed due to quota exceeded. +- invalid_command + number of commands issued and failed dues to any reason other than quota + exceeded. +- nic_receive_steering_discard + number of packets that completed RX flow + steering but were discarded due to a mismatch in flow table. +- generated_pkt_steering_fail + number of packets generated by the VNIC experiencing unexpected steering + failure (at any point in steering flow). +- handled_pkt_steering_fail + number of packets handled by the VNIC experiencing unexpected steering + failure (at any point in steering flow owned by the VNIC, including the FDB + for the eswitch owner). + +User commands examples: + +- Diagnose PF/VF vnic counters:: + + $ devlink health diagnose pci/0000:82:00.1 reporter vnic + +- Diagnose representor vnic counters (performed by supplying devlink port of the + representor, which can be obtained via devlink port command):: + + $ devlink health diagnose pci/0000:82:00.1/65537 reporter vnic + +.. note:: + This command can run over all interfaces such as PF/VF and representor ports. diff --git a/Documentation/networking/devlink/mlxsw.rst b/Documentation/networking/devlink/mlxsw.rst new file mode 100644 index 0000000000..433962225b --- /dev/null +++ b/Documentation/networking/devlink/mlxsw.rst @@ -0,0 +1,105 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================== +mlxsw devlink support +===================== + +This document describes the devlink features implemented by the ``mlxsw`` +device driver. + +Parameters +========== + +.. list-table:: Generic parameters implemented + + * - Name + - Mode + * - ``fw_load_policy`` + - driverinit + +The ``mlxsw`` driver also implements the following driver-specific +parameters. + +.. list-table:: Driver-specific parameters implemented + :widths: 5 5 5 85 + + * - Name + - Type + - Mode + - Description + * - ``acl_region_rehash_interval`` + - u32 + - runtime + - Sets an interval for periodic ACL region rehashes. The value is + specified in milliseconds, with a minimum of ``3000``. The value of + ``0`` disables periodic work entirely. The first rehash will be run + immediately after the value is set. + +The ``mlxsw`` driver supports reloading via ``DEVLINK_CMD_RELOAD`` + +Info versions +============= + +The ``mlxsw`` driver reports the following versions + +.. list-table:: devlink info versions implemented + :widths: 5 5 90 + + * - Name + - Type + - Description + * - ``hw.revision`` + - fixed + - The hardware revision for this board + * - ``fw.psid`` + - fixed + - Firmware PSID + * - ``fw.version`` + - running + - Three digit firmware version + +Line card auxiliary device info versions +======================================== + +The ``mlxsw`` driver reports the following versions for line card auxiliary device + +.. list-table:: devlink info versions implemented + :widths: 5 5 90 + + * - Name + - Type + - Description + * - ``hw.revision`` + - fixed + - The hardware revision for this line card + * - ``ini.version`` + - running + - Version of line card INI loaded + * - ``fw.psid`` + - fixed + - Line card device PSID + * - ``fw.version`` + - running + - Three digit firmware version of line card device + +Driver-specific Traps +===================== + +.. list-table:: List of Driver-specific Traps Registered by ``mlxsw`` + :widths: 5 5 90 + + * - Name + - Type + - Description + * - ``irif_disabled`` + - ``drop`` + - Traps packets that the device decided to drop because they need to be + routed from a disabled router interface (RIF). This can happen during + RIF dismantle, when the RIF is first disabled before being removed + completely + * - ``erif_disabled`` + - ``drop`` + - Traps packets that the device decided to drop because they need to be + routed through a disabled router interface (RIF). This can happen during + RIF dismantle, when the RIF is first disabled before being removed + completely diff --git a/Documentation/networking/devlink/mv88e6xxx.rst b/Documentation/networking/devlink/mv88e6xxx.rst new file mode 100644 index 0000000000..c621212a47 --- /dev/null +++ b/Documentation/networking/devlink/mv88e6xxx.rst @@ -0,0 +1,28 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================= +mv88e6xxx devlink support +========================= + +This document describes the devlink features implemented by the ``mv88e6xxx`` +device driver. + +Parameters +========== + +The ``mv88e6xxx`` driver implements the following driver-specific parameters. + +.. list-table:: Driver-specific parameters implemented + :widths: 5 5 5 85 + + * - Name + - Type + - Mode + - Description + * - ``ATU_hash`` + - u8 + - runtime + - Select one of four possible hashing algorithms for MAC addresses in + the Address Translation Unit. A value of 3 may work better than the + default of 1 when many MAC addresses have the same OUI. Only the + values 0 to 3 are valid for this parameter. diff --git a/Documentation/networking/devlink/netdevsim.rst b/Documentation/networking/devlink/netdevsim.rst new file mode 100644 index 0000000000..8848272542 --- /dev/null +++ b/Documentation/networking/devlink/netdevsim.rst @@ -0,0 +1,99 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================= +netdevsim devlink support +========================= + +This document describes the ``devlink`` features supported by the +``netdevsim`` device driver. + +Parameters +========== + +.. list-table:: Generic parameters implemented + + * - Name + - Mode + * - ``max_macs`` + - driverinit + +The ``netdevsim`` driver also implements the following driver-specific +parameters. + +.. list-table:: Driver-specific parameters implemented + :widths: 5 5 5 85 + + * - Name + - Type + - Mode + - Description + * - ``test1`` + - Boolean + - driverinit + - Test parameter used to show how a driver-specific devlink parameter + can be implemented. + +The ``netdevsim`` driver supports reloading via ``DEVLINK_CMD_RELOAD`` + +Regions +======= + +The ``netdevsim`` driver exposes a ``dummy`` region as an example of how the +devlink-region interfaces work. A snapshot is taken whenever the +``take_snapshot`` debugfs file is written to. + +Resources +========= + +The ``netdevsim`` driver exposes resources to control the number of FIB +entries, FIB rule entries and nexthops that the driver will allow. + +.. code:: shell + + $ devlink resource set netdevsim/netdevsim0 path /IPv4/fib size 96 + $ devlink resource set netdevsim/netdevsim0 path /IPv4/fib-rules size 16 + $ devlink resource set netdevsim/netdevsim0 path /IPv6/fib size 64 + $ devlink resource set netdevsim/netdevsim0 path /IPv6/fib-rules size 16 + $ devlink resource set netdevsim/netdevsim0 path /nexthops size 16 + $ devlink dev reload netdevsim/netdevsim0 + +Rate objects +============ + +The ``netdevsim`` driver supports rate objects management, which includes: + +- registerging/unregistering leaf rate objects per VF devlink port; +- creation/deletion node rate objects; +- setting tx_share and tx_max rate values for any rate object type; +- setting parent node for any rate object type. + +Rate nodes and their parameters are exposed in ``netdevsim`` debugfs in RO mode. +For example created rate node with name ``some_group``: + +.. code:: shell + + $ ls /sys/kernel/debug/netdevsim/netdevsim0/rate_groups/some_group + rate_parent tx_max tx_share + +Same parameters are exposed for leaf objects in corresponding ports directories. +For ex.: + +.. code:: shell + + $ ls /sys/kernel/debug/netdevsim/netdevsim0/ports/1 + dev ethtool rate_parent tx_max tx_share + +Driver-specific Traps +===================== + +.. list-table:: List of Driver-specific Traps Registered by ``netdevsim`` + :widths: 5 5 90 + + * - Name + - Type + - Description + * - ``fid_miss`` + - ``exception`` + - When a packet enters the device it is classified to a filtering + identifier (FID) based on the ingress port and VLAN. This trap is used + to trap packets for which a FID could not be found diff --git a/Documentation/networking/devlink/nfp.rst b/Documentation/networking/devlink/nfp.rst new file mode 100644 index 0000000000..a1717db0df --- /dev/null +++ b/Documentation/networking/devlink/nfp.rst @@ -0,0 +1,65 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=================== +nfp devlink support +=================== + +This document describes the devlink features implemented by the ``nfp`` +device driver. + +Parameters +========== + +.. list-table:: Generic parameters implemented + + * - Name + - Mode + * - ``fw_load_policy`` + - permanent + * - ``reset_dev_on_drv_probe`` + - permanent + +Info versions +============= + +The ``nfp`` driver reports the following versions + +.. list-table:: devlink info versions implemented + :widths: 5 5 90 + + * - Name + - Type + - Description + * - ``board.id`` + - fixed + - Part number identifying the board design + * - ``board.rev`` + - fixed + - Revision of the board design + * - ``board.manufacture`` + - fixed + - Vendor of the board design + * - ``board.model`` + - fixed + - Model name of the board design + * - ``fw.bundle_id`` + - stored, running + - Firmware bundle id + * - ``fw.mgmt`` + - stored, running + - Version of the management firmware + * - ``fw.cpld`` + - stored, running + - The CPLD firmware component version + * - ``fw.app`` + - stored, running + - The APP firmware component version + * - ``fw.undi`` + - stored, running + - The UNDI firmware component version + * - ``fw.ncsi`` + - stored, running + - The NSCI firmware component version + * - ``chip.init`` + - stored, running + - The CFGR firmware component version diff --git a/Documentation/networking/devlink/octeontx2.rst b/Documentation/networking/devlink/octeontx2.rst new file mode 100644 index 0000000000..610de99b72 --- /dev/null +++ b/Documentation/networking/devlink/octeontx2.rst @@ -0,0 +1,42 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================= +octeontx2 devlink support +========================= + +This document describes the devlink features implemented by the ``octeontx2 AF, PF and VF`` +device drivers. + +Parameters +========== + +The ``octeontx2 PF and VF`` drivers implement the following driver-specific parameters. + +.. list-table:: Driver-specific parameters implemented + :widths: 5 5 5 85 + + * - Name + - Type + - Mode + - Description + * - ``mcam_count`` + - u16 + - runtime + - Select number of match CAM entries to be allocated for an interface. + The same is used for ntuple filters of the interface. Supported by + PF and VF drivers. + +The ``octeontx2 AF`` driver implements the following driver-specific parameters. + +.. list-table:: Driver-specific parameters implemented + :widths: 5 5 5 85 + + * - Name + - Type + - Mode + - Description + * - ``dwrr_mtu`` + - u32 + - runtime + - Use to set the quantum which hardware uses for scheduling among transmit queues. + Hardware uses weighted DWRR algorithm to schedule among all transmit queues. diff --git a/Documentation/networking/devlink/prestera.rst b/Documentation/networking/devlink/prestera.rst new file mode 100644 index 0000000000..96b1124e61 --- /dev/null +++ b/Documentation/networking/devlink/prestera.rst @@ -0,0 +1,141 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======================== +prestera devlink support +======================== + +This document describes the devlink features implemented by the ``prestera`` +device driver. + +Driver-specific Traps +===================== + +.. list-table:: List of Driver-specific Traps Registered by ``prestera`` + :widths: 5 5 90 + + * - Name + - Type + - Description +.. list-table:: List of Driver-specific Traps Registered by ``prestera`` + :widths: 5 5 90 + + * - Name + - Type + - Description + * - ``arp_bc`` + - ``trap`` + - Traps ARP broadcast packets (both requests/responses) + * - ``is_is`` + - ``trap`` + - Traps IS-IS packets + * - ``ospf`` + - ``trap`` + - Traps OSPF packets + * - ``ip_bc_mac`` + - ``trap`` + - Traps IPv4 packets with broadcast DA Mac address + * - ``stp`` + - ``trap`` + - Traps STP BPDU + * - ``lacp`` + - ``trap`` + - Traps LACP packets + * - ``lldp`` + - ``trap`` + - Traps LLDP packets + * - ``router_mc`` + - ``trap`` + - Traps multicast packets + * - ``vrrp`` + - ``trap`` + - Traps VRRP packets + * - ``dhcp`` + - ``trap`` + - Traps DHCP packets + * - ``mtu_error`` + - ``trap`` + - Traps (exception) packets that exceeded port's MTU + * - ``mac_to_me`` + - ``trap`` + - Traps packets with switch-port's DA Mac address + * - ``ttl_error`` + - ``trap`` + - Traps (exception) IPv4 packets whose TTL exceeded + * - ``ipv4_options`` + - ``trap`` + - Traps (exception) packets due to the malformed IPV4 header options + * - ``ip_default_route`` + - ``trap`` + - Traps packets that have no specific IP interface (IP to me) and no forwarding prefix + * - ``local_route`` + - ``trap`` + - Traps packets that have been send to one of switch IP interfaces addresses + * - ``ipv4_icmp_redirect`` + - ``trap`` + - Traps (exception) IPV4 ICMP redirect packets + * - ``arp_response`` + - ``trap`` + - Traps ARP replies packets that have switch-port's DA Mac address + * - ``acl_code_0`` + - ``trap`` + - Traps packets that have ACL priority set to 0 (tc pref 0) + * - ``acl_code_1`` + - ``trap`` + - Traps packets that have ACL priority set to 1 (tc pref 1) + * - ``acl_code_2`` + - ``trap`` + - Traps packets that have ACL priority set to 2 (tc pref 2) + * - ``acl_code_3`` + - ``trap`` + - Traps packets that have ACL priority set to 3 (tc pref 3) + * - ``acl_code_4`` + - ``trap`` + - Traps packets that have ACL priority set to 4 (tc pref 4) + * - ``acl_code_5`` + - ``trap`` + - Traps packets that have ACL priority set to 5 (tc pref 5) + * - ``acl_code_6`` + - ``trap`` + - Traps packets that have ACL priority set to 6 (tc pref 6) + * - ``acl_code_7`` + - ``trap`` + - Traps packets that have ACL priority set to 7 (tc pref 7) + * - ``ipv4_bgp`` + - ``trap`` + - Traps IPv4 BGP packets + * - ``ssh`` + - ``trap`` + - Traps SSH packets + * - ``telnet`` + - ``trap`` + - Traps Telnet packets + * - ``icmp`` + - ``trap`` + - Traps ICMP packets + * - ``rxdma_drop`` + - ``drop`` + - Drops packets (RxDMA) due to the lack of ingress buffers etc. + * - ``port_no_vlan`` + - ``drop`` + - Drops packets due to faulty-configured network or due to internal bug (config issue). + * - ``local_port`` + - ``drop`` + - Drops packets whose decision (FDB entry) is to bridge packet back to the incoming port/trunk. + * - ``invalid_sa`` + - ``drop`` + - Drops packets with multicast source MAC address. + * - ``illegal_ip_addr`` + - ``drop`` + - Drops packets with illegal SIP/DIP multicast/unicast addresses. + * - ``illegal_ipv4_hdr`` + - ``drop`` + - Drops packets with illegal IPV4 header. + * - ``ip_uc_dip_da_mismatch`` + - ``drop`` + - Drops packets with destination MAC being unicast, but destination IP address being multicast. + * - ``ip_sip_is_zero`` + - ``drop`` + - Drops packets with zero (0) IPV4 source address. + * - ``met_red`` + - ``drop`` + - Drops non-conforming packets (dropped by Ingress policer, metering drop), e.g. packet rate exceeded configured bandwidth. diff --git a/Documentation/networking/devlink/qed.rst b/Documentation/networking/devlink/qed.rst new file mode 100644 index 0000000000..805c6f6362 --- /dev/null +++ b/Documentation/networking/devlink/qed.rst @@ -0,0 +1,26 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=================== +qed devlink support +=================== + +This document describes the devlink features implemented by the ``qed`` core +device driver. + +Parameters +========== + +The ``qed`` driver implements the following driver-specific parameters. + +.. list-table:: Driver-specific parameters implemented + :widths: 5 5 5 85 + + * - Name + - Type + - Mode + - Description + * - ``iwarp_cmt`` + - Boolean + - runtime + - Enable iWARP functionality for 100g devices. Note that this impacts + L2 performance, and is therefore not enabled by default. diff --git a/Documentation/networking/devlink/sfc.rst b/Documentation/networking/devlink/sfc.rst new file mode 100644 index 0000000000..db64a1bd97 --- /dev/null +++ b/Documentation/networking/devlink/sfc.rst @@ -0,0 +1,57 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=================== +sfc devlink support +=================== + +This document describes the devlink features implemented by the ``sfc`` +device driver for the ef100 device. + +Info versions +============= + +The ``sfc`` driver reports the following versions + +.. list-table:: devlink info versions implemented + :widths: 5 5 90 + + * - Name + - Type + - Description + * - ``fw.mgmt.suc`` + - running + - For boards where the management function is split between multiple + control units, this is the SUC control unit's firmware version. + * - ``fw.mgmt.cmc`` + - running + - For boards where the management function is split between multiple + control units, this is the CMC control unit's firmware version. + * - ``fpga.rev`` + - running + - FPGA design revision. + * - ``fpga.app`` + - running + - Datapath programmable logic version. + * - ``fw.app`` + - running + - Datapath software/microcode/firmware version. + * - ``coproc.boot`` + - running + - SmartNIC application co-processor (APU) first stage boot loader version. + * - ``coproc.uboot`` + - running + - SmartNIC application co-processor (APU) co-operating system loader version. + * - ``coproc.main`` + - running + - SmartNIC application co-processor (APU) main operating system version. + * - ``coproc.recovery`` + - running + - SmartNIC application co-processor (APU) recovery operating system version. + * - ``fw.exprom`` + - running + - Expansion ROM version. For boards where the expansion ROM is split between + multiple images (e.g. PXE and UEFI), this is the specifically the PXE boot + ROM version. + * - ``fw.uefi`` + - running + - UEFI driver version (No UNDI support). diff --git a/Documentation/networking/devlink/ti-cpsw-switch.rst b/Documentation/networking/devlink/ti-cpsw-switch.rst new file mode 100644 index 0000000000..dc399e32ab --- /dev/null +++ b/Documentation/networking/devlink/ti-cpsw-switch.rst @@ -0,0 +1,31 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================== +ti-cpsw-switch devlink support +============================== + +This document describes the devlink features implemented by the ``ti-cpsw-switch`` +device driver. + +Parameters +========== + +The ``ti-cpsw-switch`` driver implements the following driver-specific +parameters. + +.. list-table:: Driver-specific parameters implemented + :widths: 5 5 5 85 + + * - Name + - Type + - Mode + - Description + * - ``ale_bypass`` + - Boolean + - runtime + - Enables ALE_CONTROL(4).BYPASS mode for debugging purposes. In this + mode, all packets will be sent to the host port only. + * - ``switch_mode`` + - Boolean + - runtime + - Enable switch mode diff --git a/Documentation/networking/dns_resolver.rst b/Documentation/networking/dns_resolver.rst new file mode 100644 index 0000000000..add4d59a99 --- /dev/null +++ b/Documentation/networking/dns_resolver.rst @@ -0,0 +1,155 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=================== +DNS Resolver Module +=================== + +.. Contents: + + - Overview. + - Compilation. + - Setting up. + - Usage. + - Mechanism. + - Debugging. + + +Overview +======== + +The DNS resolver module provides a way for kernel services to make DNS queries +by way of requesting a key of key type dns_resolver. These queries are +upcalled to userspace through /sbin/request-key. + +These routines must be supported by userspace tools dns.upcall, cifs.upcall and +request-key. It is under development and does not yet provide the full feature +set. The features it does support include: + + (*) Implements the dns_resolver key_type to contact userspace. + +It does not yet support the following AFS features: + + (*) Dns query support for AFSDB resource record. + +This code is extracted from the CIFS filesystem. + + +Compilation +=========== + +The module should be enabled by turning on the kernel configuration options:: + + CONFIG_DNS_RESOLVER - tristate "DNS Resolver support" + + +Setting up +========== + +To set up this facility, the /etc/request-key.conf file must be altered so that +/sbin/request-key can appropriately direct the upcalls. For example, to handle +basic dname to IPv4/IPv6 address resolution, the following line should be +added:: + + + #OP TYPE DESC CO-INFO PROGRAM ARG1 ARG2 ARG3 ... + #====== ============ ======= ======= ========================== + create dns_resolver * * /usr/sbin/cifs.upcall %k + +To direct a query for query type 'foo', a line of the following should be added +before the more general line given above as the first match is the one taken:: + + create dns_resolver foo:* * /usr/sbin/dns.foo %k + + +Usage +===== + +To make use of this facility, one of the following functions that are +implemented in the module can be called after doing:: + + #include <linux/dns_resolver.h> + + :: + + int dns_query(const char *type, const char *name, size_t namelen, + const char *options, char **_result, time_t *_expiry); + + This is the basic access function. It looks for a cached DNS query and if + it doesn't find it, it upcalls to userspace to make a new DNS query, which + may then be cached. The key description is constructed as a string of the + form:: + + [<type>:]<name> + + where <type> optionally specifies the particular upcall program to invoke, + and thus the type of query to do, and <name> specifies the string to be + looked up. The default query type is a straight hostname to IP address + set lookup. + + The name parameter is not required to be a NUL-terminated string, and its + length should be given by the namelen argument. + + The options parameter may be NULL or it may be a set of options + appropriate to the query type. + + The return value is a string appropriate to the query type. For instance, + for the default query type it is just a list of comma-separated IPv4 and + IPv6 addresses. The caller must free the result. + + The length of the result string is returned on success, and a negative + error code is returned otherwise. -EKEYREJECTED will be returned if the + DNS lookup failed. + + If _expiry is non-NULL, the expiry time (TTL) of the result will be + returned also. + +The kernel maintains an internal keyring in which it caches looked up keys. +This can be cleared by any process that has the CAP_SYS_ADMIN capability by +the use of KEYCTL_KEYRING_CLEAR on the keyring ID. + + +Reading DNS Keys from Userspace +=============================== + +Keys of dns_resolver type can be read from userspace using keyctl_read() or +"keyctl read/print/pipe". + + +Mechanism +========= + +The dnsresolver module registers a key type called "dns_resolver". Keys of +this type are used to transport and cache DNS lookup results from userspace. + +When dns_query() is invoked, it calls request_key() to search the local +keyrings for a cached DNS result. If that fails to find one, it upcalls to +userspace to get a new result. + +Upcalls to userspace are made through the request_key() upcall vector, and are +directed by means of configuration lines in /etc/request-key.conf that tell +/sbin/request-key what program to run to instantiate the key. + +The upcall handler program is responsible for querying the DNS, processing the +result into a form suitable for passing to the keyctl_instantiate_key() +routine. This then passes the data to dns_resolver_instantiate() which strips +off and processes any options included in the data, and then attaches the +remainder of the string to the key as its payload. + +The upcall handler program should set the expiry time on the key to that of the +lowest TTL of all the records it has extracted a result from. This means that +the key will be discarded and recreated when the data it holds has expired. + +dns_query() returns a copy of the value attached to the key, or an error if +that is indicated instead. + +See <file:Documentation/security/keys/request-key.rst> for further +information about request-key function. + + +Debugging +========= + +Debugging messages can be turned on dynamically by writing a 1 into the +following file:: + + /sys/module/dnsresolver/parameters/debug diff --git a/Documentation/networking/driver.rst b/Documentation/networking/driver.rst new file mode 100644 index 0000000000..4f5dfa9c02 --- /dev/null +++ b/Documentation/networking/driver.rst @@ -0,0 +1,127 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================== +Softnet Driver Issues +===================== + +Probing guidelines +================== + +Address validation +------------------ + +Any hardware layer address you obtain for your device should +be verified. For example, for ethernet check it with +linux/etherdevice.h:is_valid_ether_addr() + +Close/stop guidelines +===================== + +Quiescence +---------- + +After the ndo_stop routine has been called, the hardware must +not receive or transmit any data. All in flight packets must +be aborted. If necessary, poll or wait for completion of +any reset commands. + +Auto-close +---------- + +The ndo_stop routine will be called by unregister_netdevice +if device is still UP. + +Transmit path guidelines +======================== + +Stop queues in advance +---------------------- + +The ndo_start_xmit method must not return NETDEV_TX_BUSY under +any normal circumstances. It is considered a hard error unless +there is no way your device can tell ahead of time when its +transmit function will become busy. + +Instead it must maintain the queue properly. For example, +for a driver implementing scatter-gather this means: + +.. code-block:: c + + static u32 drv_tx_avail(struct drv_ring *dr) + { + u32 used = READ_ONCE(dr->prod) - READ_ONCE(dr->cons); + + return dr->tx_ring_size - (used & bp->tx_ring_mask); + } + + static netdev_tx_t drv_hard_start_xmit(struct sk_buff *skb, + struct net_device *dev) + { + struct drv *dp = netdev_priv(dev); + struct netdev_queue *txq; + struct drv_ring *dr; + int idx; + + idx = skb_get_queue_mapping(skb); + dr = dp->tx_rings[idx]; + txq = netdev_get_tx_queue(dev, idx); + + //... + /* This should be a very rare race - log it. */ + if (drv_tx_avail(dr) <= skb_shinfo(skb)->nr_frags + 1) { + netif_stop_queue(dev); + netdev_warn(dev, "Tx Ring full when queue awake!\n"); + return NETDEV_TX_BUSY; + } + + //... queue packet to card ... + + netdev_tx_sent_queue(txq, skb->len); + + //... update tx producer index using WRITE_ONCE() ... + + if (!netif_txq_maybe_stop(txq, drv_tx_avail(dr), + MAX_SKB_FRAGS + 1, 2 * MAX_SKB_FRAGS)) + dr->stats.stopped++; + + //... + return NETDEV_TX_OK; + } + +And then at the end of your TX reclamation event handling: + +.. code-block:: c + + //... update tx consumer index using WRITE_ONCE() ... + + netif_txq_completed_wake(txq, cmpl_pkts, cmpl_bytes, + drv_tx_avail(dr), 2 * MAX_SKB_FRAGS); + +Lockless queue stop / wake helper macros +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +.. kernel-doc:: include/net/netdev_queues.h + :doc: Lockless queue stopping / waking helpers. + +No exclusive ownership +---------------------- + +An ndo_start_xmit method must not modify the shared parts of a +cloned SKB. + +Timely completions +------------------ + +Do not forget that once you return NETDEV_TX_OK from your +ndo_start_xmit method, it is your driver's responsibility to free +up the SKB and in some finite amount of time. + +For example, this means that it is not allowed for your TX +mitigation scheme to let TX packets "hang out" in the TX +ring unreclaimed forever if no new TX packets are sent. +This error can deadlock sockets waiting for send buffer room +to be freed up. + +If you return NETDEV_TX_BUSY from the ndo_start_xmit method, you +must not keep any reference to that SKB and you must not attempt +to free it up. diff --git a/Documentation/networking/dsa/b53.rst b/Documentation/networking/dsa/b53.rst new file mode 100644 index 0000000000..b41637cdb8 --- /dev/null +++ b/Documentation/networking/dsa/b53.rst @@ -0,0 +1,183 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================================== +Broadcom RoboSwitch Ethernet switch driver +========================================== + +The Broadcom RoboSwitch Ethernet switch family is used in quite a range of +xDSL router, cable modems and other multimedia devices. + +The actual implementation supports the devices BCM5325E, BCM5365, BCM539x, +BCM53115 and BCM53125 as well as BCM63XX. + +Implementation details +====================== + +The driver is located in ``drivers/net/dsa/b53/`` and is implemented as a +DSA driver; see ``Documentation/networking/dsa/dsa.rst`` for details on the +subsystem and what it provides. + +The switch is, if possible, configured to enable a Broadcom specific 4-bytes +switch tag which gets inserted by the switch for every packet forwarded to the +CPU interface, conversely, the CPU network interface should insert a similar +tag for packets entering the CPU port. The tag format is described in +``net/dsa/tag_brcm.c``. + +The configuration of the device depends on whether or not tagging is +supported. + +The interface names and example network configuration are used according the +configuration described in the :ref:`dsa-config-showcases`. + +Configuration with tagging support +---------------------------------- + +The tagging based configuration is desired. It is not specific to the b53 +DSA driver and will work like all DSA drivers which supports tagging. + +See :ref:`dsa-tagged-configuration`. + +Configuration without tagging support +------------------------------------- + +Older models (5325, 5365) support a different tag format that is not supported +yet. 539x and 531x5 require managed mode and some special handling, which is +also not yet supported. The tagging support is disabled in these cases and the +switch need a different configuration. + +The configuration slightly differ from the :ref:`dsa-vlan-configuration`. + +The b53 tags the CPU port in all VLANs, since otherwise any PVID untagged +VLAN programming would basically change the CPU port's default PVID and make +it untagged, undesirable. + +In difference to the configuration described in :ref:`dsa-vlan-configuration` +the default VLAN 1 has to be removed from the slave interface configuration in +single port and gateway configuration, while there is no need to add an extra +VLAN configuration in the bridge showcase. + +single port +~~~~~~~~~~~ +The configuration can only be set up via VLAN tagging and bridge setup. +By default packages are tagged with vid 1: + +.. code-block:: sh + + # tag traffic on CPU port + ip link add link eth0 name eth0.1 type vlan id 1 + ip link add link eth0 name eth0.2 type vlan id 2 + ip link add link eth0 name eth0.3 type vlan id 3 + + # The master interface needs to be brought up before the slave ports. + ip link set eth0 up + ip link set eth0.1 up + ip link set eth0.2 up + ip link set eth0.3 up + + # bring up the slave interfaces + ip link set wan up + ip link set lan1 up + ip link set lan2 up + + # create bridge + ip link add name br0 type bridge + + # activate VLAN filtering + ip link set dev br0 type bridge vlan_filtering 1 + + # add ports to bridges + ip link set dev wan master br0 + ip link set dev lan1 master br0 + ip link set dev lan2 master br0 + + # tag traffic on ports + bridge vlan add dev lan1 vid 2 pvid untagged + bridge vlan del dev lan1 vid 1 + bridge vlan add dev lan2 vid 3 pvid untagged + bridge vlan del dev lan2 vid 1 + + # configure the VLANs + ip addr add 192.0.2.1/30 dev eth0.1 + ip addr add 192.0.2.5/30 dev eth0.2 + ip addr add 192.0.2.9/30 dev eth0.3 + + # bring up the bridge devices + ip link set br0 up + + +bridge +~~~~~~ + +.. code-block:: sh + + # tag traffic on CPU port + ip link add link eth0 name eth0.1 type vlan id 1 + + # The master interface needs to be brought up before the slave ports. + ip link set eth0 up + ip link set eth0.1 up + + # bring up the slave interfaces + ip link set wan up + ip link set lan1 up + ip link set lan2 up + + # create bridge + ip link add name br0 type bridge + + # activate VLAN filtering + ip link set dev br0 type bridge vlan_filtering 1 + + # add ports to bridge + ip link set dev wan master br0 + ip link set dev lan1 master br0 + ip link set dev lan2 master br0 + ip link set eth0.1 master br0 + + # configure the bridge + ip addr add 192.0.2.129/25 dev br0 + + # bring up the bridge + ip link set dev br0 up + +gateway +~~~~~~~ + +.. code-block:: sh + + # tag traffic on CPU port + ip link add link eth0 name eth0.1 type vlan id 1 + ip link add link eth0 name eth0.2 type vlan id 2 + + # The master interface needs to be brought up before the slave ports. + ip link set eth0 up + ip link set eth0.1 up + ip link set eth0.2 up + + # bring up the slave interfaces + ip link set wan up + ip link set lan1 up + ip link set lan2 up + + # create bridge + ip link add name br0 type bridge + + # activate VLAN filtering + ip link set dev br0 type bridge vlan_filtering 1 + + # add ports to bridges + ip link set dev wan master br0 + ip link set eth0.1 master br0 + ip link set dev lan1 master br0 + ip link set dev lan2 master br0 + + # tag traffic on ports + bridge vlan add dev wan vid 2 pvid untagged + bridge vlan del dev wan vid 1 + + # configure the VLANs + ip addr add 192.0.2.1/30 dev eth0.2 + ip addr add 192.0.2.129/25 dev br0 + + # bring up the bridge devices + ip link set br0 up diff --git a/Documentation/networking/dsa/bcm_sf2.rst b/Documentation/networking/dsa/bcm_sf2.rst new file mode 100644 index 0000000000..dee234039e --- /dev/null +++ b/Documentation/networking/dsa/bcm_sf2.rst @@ -0,0 +1,115 @@ +============================================= +Broadcom Starfighter 2 Ethernet switch driver +============================================= + +Broadcom's Starfighter 2 Ethernet switch hardware block is commonly found and +deployed in the following products: + +- xDSL gateways such as BCM63138 +- streaming/multimedia Set Top Box such as BCM7445 +- Cable Modem/residential gateways such as BCM7145/BCM3390 + +The switch is typically deployed in a configuration involving between 5 to 13 +ports, offering a range of built-in and customizable interfaces: + +- single integrated Gigabit PHY +- quad integrated Gigabit PHY +- quad external Gigabit PHY w/ MDIO multiplexer +- integrated MoCA PHY +- several external MII/RevMII/GMII/RGMII interfaces + +The switch also supports specific congestion control features which allow MoCA +fail-over not to lose packets during a MoCA role re-election, as well as out of +band back-pressure to the host CPU network interface when downstream interfaces +are connected at a lower speed. + +The switch hardware block is typically interfaced using MMIO accesses and +contains a bunch of sub-blocks/registers: + +- ``SWITCH_CORE``: common switch registers +- ``SWITCH_REG``: external interfaces switch register +- ``SWITCH_MDIO``: external MDIO bus controller (there is another one in SWITCH_CORE, + which is used for indirect PHY accesses) +- ``SWITCH_INDIR_RW``: 64-bits wide register helper block +- ``SWITCH_INTRL2_0/1``: Level-2 interrupt controllers +- ``SWITCH_ACB``: Admission control block +- ``SWITCH_FCB``: Fail-over control block + +Implementation details +====================== + +The driver is located in ``drivers/net/dsa/bcm_sf2.c`` and is implemented as a DSA +driver; see ``Documentation/networking/dsa/dsa.rst`` for details on the subsystem +and what it provides. + +The SF2 switch is configured to enable a Broadcom specific 4-bytes switch tag +which gets inserted by the switch for every packet forwarded to the CPU +interface, conversely, the CPU network interface should insert a similar tag for +packets entering the CPU port. The tag format is described in +``net/dsa/tag_brcm.c``. + +Overall, the SF2 driver is a fairly regular DSA driver; there are a few +specifics covered below. + +Device Tree probing +------------------- + +The DSA platform device driver is probed using a specific compatible string +provided in ``net/dsa/dsa.c``. The reason for that is because the DSA subsystem gets +registered as a platform device driver currently. DSA will provide the needed +device_node pointers which are then accessible by the switch driver setup +function to setup resources such as register ranges and interrupts. This +currently works very well because none of the of_* functions utilized by the +driver require a struct device to be bound to a struct device_node, but things +may change in the future. + +MDIO indirect accesses +---------------------- + +Due to a limitation in how Broadcom switches have been designed, external +Broadcom switches connected to a SF2 require the use of the DSA slave MDIO bus +in order to properly configure them. By default, the SF2 pseudo-PHY address, and +an external switch pseudo-PHY address will both be snooping for incoming MDIO +transactions, since they are at the same address (30), resulting in some kind of +"double" programming. Using DSA, and setting ``ds->phys_mii_mask`` accordingly, we +selectively divert reads and writes towards external Broadcom switches +pseudo-PHY addresses. Newer revisions of the SF2 hardware have introduced a +configurable pseudo-PHY address which circumvents the initial design limitation. + +Multimedia over CoAxial (MoCA) interfaces +----------------------------------------- + +MoCA interfaces are fairly specific and require the use of a firmware blob which +gets loaded onto the MoCA processor(s) for packet processing. The switch +hardware contains logic which will assert/de-assert link states accordingly for +the MoCA interface whenever the MoCA coaxial cable gets disconnected or the +firmware gets reloaded. The SF2 driver relies on such events to properly set its +MoCA interface carrier state and properly report this to the networking stack. + +The MoCA interfaces are supported using the PHY library's fixed PHY/emulated PHY +device and the switch driver registers a ``fixed_link_update`` callback for such +PHYs which reflects the link state obtained from the interrupt handler. + + +Power Management +---------------- + +Whenever possible, the SF2 driver tries to minimize the overall switch power +consumption by applying a combination of: + +- turning off internal buffers/memories +- disabling packet processing logic +- putting integrated PHYs in IDDQ/low-power +- reducing the switch core clock based on the active port count +- enabling and advertising EEE +- turning off RGMII data processing logic when the link goes down + +Wake-on-LAN +----------- + +Wake-on-LAN is currently implemented by utilizing the host processor Ethernet +MAC controller wake-on logic. Whenever Wake-on-LAN is requested, an intersection +between the user request and the supported host Ethernet interface WoL +capabilities is done and the intersection result gets configured. During +system-wide suspend/resume, only ports not participating in Wake-on-LAN are +disabled. diff --git a/Documentation/networking/dsa/configuration.rst b/Documentation/networking/dsa/configuration.rst new file mode 100644 index 0000000000..d2934c40f0 --- /dev/null +++ b/Documentation/networking/dsa/configuration.rst @@ -0,0 +1,458 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======================================= +DSA switch configuration from userspace +======================================= + +The DSA switch configuration is not integrated into the main userspace +network configuration suites by now and has to be performed manually. + +.. _dsa-config-showcases: + +Configuration showcases +----------------------- + +To configure a DSA switch a couple of commands need to be executed. In this +documentation some common configuration scenarios are handled as showcases: + +*single port* + Every switch port acts as a different configurable Ethernet port + +*bridge* + Every switch port is part of one configurable Ethernet bridge + +*gateway* + Every switch port except one upstream port is part of a configurable + Ethernet bridge. + The upstream port acts as different configurable Ethernet port. + +All configurations are performed with tools from iproute2, which is available +at https://www.kernel.org/pub/linux/utils/net/iproute2/ + +Through DSA every port of a switch is handled like a normal linux Ethernet +interface. The CPU port is the switch port connected to an Ethernet MAC chip. +The corresponding linux Ethernet interface is called the master interface. +All other corresponding linux interfaces are called slave interfaces. + +The slave interfaces depend on the master interface being up in order for them +to send or receive traffic. Prior to kernel v5.12, the state of the master +interface had to be managed explicitly by the user. Starting with kernel v5.12, +the behavior is as follows: + +- when a DSA slave interface is brought up, the master interface is + automatically brought up. +- when the master interface is brought down, all DSA slave interfaces are + automatically brought down. + +In this documentation the following Ethernet interfaces are used: + +*eth0* + the master interface + +*eth1* + another master interface + +*lan1* + a slave interface + +*lan2* + another slave interface + +*lan3* + a third slave interface + +*wan* + A slave interface dedicated for upstream traffic + +Further Ethernet interfaces can be configured similar. +The configured IPs and networks are: + +*single port* + * lan1: 192.0.2.1/30 (192.0.2.0 - 192.0.2.3) + * lan2: 192.0.2.5/30 (192.0.2.4 - 192.0.2.7) + * lan3: 192.0.2.9/30 (192.0.2.8 - 192.0.2.11) + +*bridge* + * br0: 192.0.2.129/25 (192.0.2.128 - 192.0.2.255) + +*gateway* + * br0: 192.0.2.129/25 (192.0.2.128 - 192.0.2.255) + * wan: 192.0.2.1/30 (192.0.2.0 - 192.0.2.3) + +.. _dsa-tagged-configuration: + +Configuration with tagging support +---------------------------------- + +The tagging based configuration is desired and supported by the majority of +DSA switches. These switches are capable to tag incoming and outgoing traffic +without using a VLAN based configuration. + +*single port* + .. code-block:: sh + + # configure each interface + ip addr add 192.0.2.1/30 dev lan1 + ip addr add 192.0.2.5/30 dev lan2 + ip addr add 192.0.2.9/30 dev lan3 + + # For kernels earlier than v5.12, the master interface needs to be + # brought up manually before the slave ports. + ip link set eth0 up + + # bring up the slave interfaces + ip link set lan1 up + ip link set lan2 up + ip link set lan3 up + +*bridge* + .. code-block:: sh + + # For kernels earlier than v5.12, the master interface needs to be + # brought up manually before the slave ports. + ip link set eth0 up + + # bring up the slave interfaces + ip link set lan1 up + ip link set lan2 up + ip link set lan3 up + + # create bridge + ip link add name br0 type bridge + + # add ports to bridge + ip link set dev lan1 master br0 + ip link set dev lan2 master br0 + ip link set dev lan3 master br0 + + # configure the bridge + ip addr add 192.0.2.129/25 dev br0 + + # bring up the bridge + ip link set dev br0 up + +*gateway* + .. code-block:: sh + + # For kernels earlier than v5.12, the master interface needs to be + # brought up manually before the slave ports. + ip link set eth0 up + + # bring up the slave interfaces + ip link set wan up + ip link set lan1 up + ip link set lan2 up + + # configure the upstream port + ip addr add 192.0.2.1/30 dev wan + + # create bridge + ip link add name br0 type bridge + + # add ports to bridge + ip link set dev lan1 master br0 + ip link set dev lan2 master br0 + + # configure the bridge + ip addr add 192.0.2.129/25 dev br0 + + # bring up the bridge + ip link set dev br0 up + +.. _dsa-vlan-configuration: + +Configuration without tagging support +------------------------------------- + +A minority of switches are not capable to use a taging protocol +(DSA_TAG_PROTO_NONE). These switches can be configured by a VLAN based +configuration. + +*single port* + The configuration can only be set up via VLAN tagging and bridge setup. + + .. code-block:: sh + + # tag traffic on CPU port + ip link add link eth0 name eth0.1 type vlan id 1 + ip link add link eth0 name eth0.2 type vlan id 2 + ip link add link eth0 name eth0.3 type vlan id 3 + + # For kernels earlier than v5.12, the master interface needs to be + # brought up manually before the slave ports. + ip link set eth0 up + ip link set eth0.1 up + ip link set eth0.2 up + ip link set eth0.3 up + + # bring up the slave interfaces + ip link set lan1 up + ip link set lan2 up + ip link set lan3 up + + # create bridge + ip link add name br0 type bridge + + # activate VLAN filtering + ip link set dev br0 type bridge vlan_filtering 1 + + # add ports to bridges + ip link set dev lan1 master br0 + ip link set dev lan2 master br0 + ip link set dev lan3 master br0 + + # tag traffic on ports + bridge vlan add dev lan1 vid 1 pvid untagged + bridge vlan add dev lan2 vid 2 pvid untagged + bridge vlan add dev lan3 vid 3 pvid untagged + + # configure the VLANs + ip addr add 192.0.2.1/30 dev eth0.1 + ip addr add 192.0.2.5/30 dev eth0.2 + ip addr add 192.0.2.9/30 dev eth0.3 + + # bring up the bridge devices + ip link set br0 up + + +*bridge* + .. code-block:: sh + + # tag traffic on CPU port + ip link add link eth0 name eth0.1 type vlan id 1 + + # For kernels earlier than v5.12, the master interface needs to be + # brought up manually before the slave ports. + ip link set eth0 up + ip link set eth0.1 up + + # bring up the slave interfaces + ip link set lan1 up + ip link set lan2 up + ip link set lan3 up + + # create bridge + ip link add name br0 type bridge + + # activate VLAN filtering + ip link set dev br0 type bridge vlan_filtering 1 + + # add ports to bridge + ip link set dev lan1 master br0 + ip link set dev lan2 master br0 + ip link set dev lan3 master br0 + ip link set eth0.1 master br0 + + # tag traffic on ports + bridge vlan add dev lan1 vid 1 pvid untagged + bridge vlan add dev lan2 vid 1 pvid untagged + bridge vlan add dev lan3 vid 1 pvid untagged + + # configure the bridge + ip addr add 192.0.2.129/25 dev br0 + + # bring up the bridge + ip link set dev br0 up + +*gateway* + .. code-block:: sh + + # tag traffic on CPU port + ip link add link eth0 name eth0.1 type vlan id 1 + ip link add link eth0 name eth0.2 type vlan id 2 + + # For kernels earlier than v5.12, the master interface needs to be + # brought up manually before the slave ports. + ip link set eth0 up + ip link set eth0.1 up + ip link set eth0.2 up + + # bring up the slave interfaces + ip link set wan up + ip link set lan1 up + ip link set lan2 up + + # create bridge + ip link add name br0 type bridge + + # activate VLAN filtering + ip link set dev br0 type bridge vlan_filtering 1 + + # add ports to bridges + ip link set dev wan master br0 + ip link set eth0.1 master br0 + ip link set dev lan1 master br0 + ip link set dev lan2 master br0 + + # tag traffic on ports + bridge vlan add dev lan1 vid 1 pvid untagged + bridge vlan add dev lan2 vid 1 pvid untagged + bridge vlan add dev wan vid 2 pvid untagged + + # configure the VLANs + ip addr add 192.0.2.1/30 dev eth0.2 + ip addr add 192.0.2.129/25 dev br0 + + # bring up the bridge devices + ip link set br0 up + +Forwarding database (FDB) management +------------------------------------ + +The existing DSA switches do not have the necessary hardware support to keep +the software FDB of the bridge in sync with the hardware tables, so the two +tables are managed separately (``bridge fdb show`` queries both, and depending +on whether the ``self`` or ``master`` flags are being used, a ``bridge fdb +add`` or ``bridge fdb del`` command acts upon entries from one or both tables). + +Up until kernel v4.14, DSA only supported user space management of bridge FDB +entries using the bridge bypass operations (which do not update the software +FDB, just the hardware one) using the ``self`` flag (which is optional and can +be omitted). + + .. code-block:: sh + + bridge fdb add dev swp0 00:01:02:03:04:05 self static + # or shorthand + bridge fdb add dev swp0 00:01:02:03:04:05 static + +Due to a bug, the bridge bypass FDB implementation provided by DSA did not +distinguish between ``static`` and ``local`` FDB entries (``static`` are meant +to be forwarded, while ``local`` are meant to be locally terminated, i.e. sent +to the host port). Instead, all FDB entries with the ``self`` flag (implicit or +explicit) are treated by DSA as ``static`` even if they are ``local``. + + .. code-block:: sh + + # This command: + bridge fdb add dev swp0 00:01:02:03:04:05 static + # behaves the same for DSA as this command: + bridge fdb add dev swp0 00:01:02:03:04:05 local + # or shorthand, because the 'local' flag is implicit if 'static' is not + # specified, it also behaves the same as: + bridge fdb add dev swp0 00:01:02:03:04:05 + +The last command is an incorrect way of adding a static bridge FDB entry to a +DSA switch using the bridge bypass operations, and works by mistake. Other +drivers will treat an FDB entry added by the same command as ``local`` and as +such, will not forward it, as opposed to DSA. + +Between kernel v4.14 and v5.14, DSA has supported in parallel two modes of +adding a bridge FDB entry to the switch: the bridge bypass discussed above, as +well as a new mode using the ``master`` flag which installs FDB entries in the +software bridge too. + + .. code-block:: sh + + bridge fdb add dev swp0 00:01:02:03:04:05 master static + +Since kernel v5.14, DSA has gained stronger integration with the bridge's +software FDB, and the support for its bridge bypass FDB implementation (using +the ``self`` flag) has been removed. This results in the following changes: + + .. code-block:: sh + + # This is the only valid way of adding an FDB entry that is supported, + # compatible with v4.14 kernels and later: + bridge fdb add dev swp0 00:01:02:03:04:05 master static + # This command is no longer buggy and the entry is properly treated as + # 'local' instead of being forwarded: + bridge fdb add dev swp0 00:01:02:03:04:05 + # This command no longer installs a static FDB entry to hardware: + bridge fdb add dev swp0 00:01:02:03:04:05 static + +Script writers are therefore encouraged to use the ``master static`` set of +flags when working with bridge FDB entries on DSA switch interfaces. + +Affinity of user ports to CPU ports +----------------------------------- + +Typically, DSA switches are attached to the host via a single Ethernet +interface, but in cases where the switch chip is discrete, the hardware design +may permit the use of 2 or more ports connected to the host, for an increase in +termination throughput. + +DSA can make use of multiple CPU ports in two ways. First, it is possible to +statically assign the termination traffic associated with a certain user port +to be processed by a certain CPU port. This way, user space can implement +custom policies of static load balancing between user ports, by spreading the +affinities according to the available CPU ports. + +Secondly, it is possible to perform load balancing between CPU ports on a per +packet basis, rather than statically assigning user ports to CPU ports. +This can be achieved by placing the DSA masters under a LAG interface (bonding +or team). DSA monitors this operation and creates a mirror of this software LAG +on the CPU ports facing the physical DSA masters that constitute the LAG slave +devices. + +To make use of multiple CPU ports, the firmware (device tree) description of +the switch must mark all the links between CPU ports and their DSA masters +using the ``ethernet`` reference/phandle. At startup, only a single CPU port +and DSA master will be used - the numerically first port from the firmware +description which has an ``ethernet`` property. It is up to the user to +configure the system for the switch to use other masters. + +DSA uses the ``rtnl_link_ops`` mechanism (with a "dsa" ``kind``) to allow +changing the DSA master of a user port. The ``IFLA_DSA_MASTER`` u32 netlink +attribute contains the ifindex of the master device that handles each slave +device. The DSA master must be a valid candidate based on firmware node +information, or a LAG interface which contains only slaves which are valid +candidates. + +Using iproute2, the following manipulations are possible: + + .. code-block:: sh + + # See the DSA master in current use + ip -d link show dev swp0 + (...) + dsa master eth0 + + # Static CPU port distribution + ip link set swp0 type dsa master eth1 + ip link set swp1 type dsa master eth0 + ip link set swp2 type dsa master eth1 + ip link set swp3 type dsa master eth0 + + # CPU ports in LAG, using explicit assignment of the DSA master + ip link add bond0 type bond mode balance-xor && ip link set bond0 up + ip link set eth1 down && ip link set eth1 master bond0 + ip link set swp0 type dsa master bond0 + ip link set swp1 type dsa master bond0 + ip link set swp2 type dsa master bond0 + ip link set swp3 type dsa master bond0 + ip link set eth0 down && ip link set eth0 master bond0 + ip -d link show dev swp0 + (...) + dsa master bond0 + + # CPU ports in LAG, relying on implicit migration of the DSA master + ip link add bond0 type bond mode balance-xor && ip link set bond0 up + ip link set eth0 down && ip link set eth0 master bond0 + ip link set eth1 down && ip link set eth1 master bond0 + ip -d link show dev swp0 + (...) + dsa master bond0 + +Notice that in the case of CPU ports under a LAG, the use of the +``IFLA_DSA_MASTER`` netlink attribute is not strictly needed, but rather, DSA +reacts to the ``IFLA_MASTER`` attribute change of its present master (``eth0``) +and migrates all user ports to the new upper of ``eth0``, ``bond0``. Similarly, +when ``bond0`` is destroyed using ``RTM_DELLINK``, DSA migrates the user ports +that were assigned to this interface to the first physical DSA master which is +eligible, based on the firmware description (it effectively reverts to the +startup configuration). + +In a setup with more than 2 physical CPU ports, it is therefore possible to mix +static user to CPU port assignment with LAG between DSA masters. It is not +possible to statically assign a user port towards a DSA master that has any +upper interfaces (this includes LAG devices - the master must always be the LAG +in this case). + +Live changing of the DSA master (and thus CPU port) affinity of a user port is +permitted, in order to allow dynamic redistribution in response to traffic. + +Physical DSA masters are allowed to join and leave at any time a LAG interface +used as a DSA master; however, DSA will reject a LAG interface as a valid +candidate for being a DSA master unless it has at least one physical DSA master +as a slave device. diff --git a/Documentation/networking/dsa/dsa.rst b/Documentation/networking/dsa/dsa.rst new file mode 100644 index 0000000000..a94ddf8334 --- /dev/null +++ b/Documentation/networking/dsa/dsa.rst @@ -0,0 +1,1129 @@ +============ +Architecture +============ + +This document describes the **Distributed Switch Architecture (DSA)** subsystem +design principles, limitations, interactions with other subsystems, and how to +develop drivers for this subsystem as well as a TODO for developers interested +in joining the effort. + +Design principles +================= + +The Distributed Switch Architecture subsystem was primarily designed to +support Marvell Ethernet switches (MV88E6xxx, a.k.a. Link Street product +line) using Linux, but has since evolved to support other vendors as well. + +The original philosophy behind this design was to be able to use unmodified +Linux tools such as bridge, iproute2, ifconfig to work transparently whether +they configured/queried a switch port network device or a regular network +device. + +An Ethernet switch typically comprises multiple front-panel ports and one +or more CPU or management ports. The DSA subsystem currently relies on the +presence of a management port connected to an Ethernet controller capable of +receiving Ethernet frames from the switch. This is a very common setup for all +kinds of Ethernet switches found in Small Home and Office products: routers, +gateways, or even top-of-rack switches. This host Ethernet controller will +be later referred to as "master" and "cpu" in DSA terminology and code. + +The D in DSA stands for Distributed, because the subsystem has been designed +with the ability to configure and manage cascaded switches on top of each other +using upstream and downstream Ethernet links between switches. These specific +ports are referred to as "dsa" ports in DSA terminology and code. A collection +of multiple switches connected to each other is called a "switch tree". + +For each front-panel port, DSA creates specialized network devices which are +used as controlling and data-flowing endpoints for use by the Linux networking +stack. These specialized network interfaces are referred to as "slave" network +interfaces in DSA terminology and code. + +The ideal case for using DSA is when an Ethernet switch supports a "switch tag" +which is a hardware feature making the switch insert a specific tag for each +Ethernet frame it receives to/from specific ports to help the management +interface figure out: + +- what port is this frame coming from +- what was the reason why this frame got forwarded +- how to send CPU originated traffic to specific ports + +The subsystem does support switches not capable of inserting/stripping tags, but +the features might be slightly limited in that case (traffic separation relies +on Port-based VLAN IDs). + +Note that DSA does not currently create network interfaces for the "cpu" and +"dsa" ports because: + +- the "cpu" port is the Ethernet switch facing side of the management + controller, and as such, would create a duplication of feature, since you + would get two interfaces for the same conduit: master netdev, and "cpu" netdev + +- the "dsa" port(s) are just conduits between two or more switches, and as such + cannot really be used as proper network interfaces either, only the + downstream, or the top-most upstream interface makes sense with that model + +Switch tagging protocols +------------------------ + +DSA supports many vendor-specific tagging protocols, one software-defined +tagging protocol, and a tag-less mode as well (``DSA_TAG_PROTO_NONE``). + +The exact format of the tag protocol is vendor specific, but in general, they +all contain something which: + +- identifies which port the Ethernet frame came from/should be sent to +- provides a reason why this frame was forwarded to the management interface + +All tagging protocols are in ``net/dsa/tag_*.c`` files and implement the +methods of the ``struct dsa_device_ops`` structure, which are detailed below. + +Tagging protocols generally fall in one of three categories: + +1. The switch-specific frame header is located before the Ethernet header, + shifting to the right (from the perspective of the DSA master's frame + parser) the MAC DA, MAC SA, EtherType and the entire L2 payload. +2. The switch-specific frame header is located before the EtherType, keeping + the MAC DA and MAC SA in place from the DSA master's perspective, but + shifting the 'real' EtherType and L2 payload to the right. +3. The switch-specific frame header is located at the tail of the packet, + keeping all frame headers in place and not altering the view of the packet + that the DSA master's frame parser has. + +A tagging protocol may tag all packets with switch tags of the same length, or +the tag length might vary (for example packets with PTP timestamps might +require an extended switch tag, or there might be one tag length on TX and a +different one on RX). Either way, the tagging protocol driver must populate the +``struct dsa_device_ops::needed_headroom`` and/or ``struct dsa_device_ops::needed_tailroom`` +with the length in octets of the longest switch frame header/trailer. The DSA +framework will automatically adjust the MTU of the master interface to +accommodate for this extra size in order for DSA user ports to support the +standard MTU (L2 payload length) of 1500 octets. The ``needed_headroom`` and +``needed_tailroom`` properties are also used to request from the network stack, +on a best-effort basis, the allocation of packets with enough extra space such +that the act of pushing the switch tag on transmission of a packet does not +cause it to reallocate due to lack of memory. + +Even though applications are not expected to parse DSA-specific frame headers, +the format on the wire of the tagging protocol represents an Application Binary +Interface exposed by the kernel towards user space, for decoders such as +``libpcap``. The tagging protocol driver must populate the ``proto`` member of +``struct dsa_device_ops`` with a value that uniquely describes the +characteristics of the interaction required between the switch hardware and the +data path driver: the offset of each bit field within the frame header and any +stateful processing required to deal with the frames (as may be required for +PTP timestamping). + +From the perspective of the network stack, all switches within the same DSA +switch tree use the same tagging protocol. In case of a packet transiting a +fabric with more than one switch, the switch-specific frame header is inserted +by the first switch in the fabric that the packet was received on. This header +typically contains information regarding its type (whether it is a control +frame that must be trapped to the CPU, or a data frame to be forwarded). +Control frames should be decapsulated only by the software data path, whereas +data frames might also be autonomously forwarded towards other user ports of +other switches from the same fabric, and in this case, the outermost switch +ports must decapsulate the packet. + +Note that in certain cases, it might be the case that the tagging format used +by a leaf switch (not connected directly to the CPU) is not the same as what +the network stack sees. This can be seen with Marvell switch trees, where the +CPU port can be configured to use either the DSA or the Ethertype DSA (EDSA) +format, but the DSA links are configured to use the shorter (without Ethertype) +DSA frame header, in order to reduce the autonomous packet forwarding overhead. +It still remains the case that, if the DSA switch tree is configured for the +EDSA tagging protocol, the operating system sees EDSA-tagged packets from the +leaf switches that tagged them with the shorter DSA header. This can be done +because the Marvell switch connected directly to the CPU is configured to +perform tag translation between DSA and EDSA (which is simply the operation of +adding or removing the ``ETH_P_EDSA`` EtherType and some padding octets). + +It is possible to construct cascaded setups of DSA switches even if their +tagging protocols are not compatible with one another. In this case, there are +no DSA links in this fabric, and each switch constitutes a disjoint DSA switch +tree. The DSA links are viewed as simply a pair of a DSA master (the out-facing +port of the upstream DSA switch) and a CPU port (the in-facing port of the +downstream DSA switch). + +The tagging protocol of the attached DSA switch tree can be viewed through the +``dsa/tagging`` sysfs attribute of the DSA master:: + + cat /sys/class/net/eth0/dsa/tagging + +If the hardware and driver are capable, the tagging protocol of the DSA switch +tree can be changed at runtime. This is done by writing the new tagging +protocol name to the same sysfs device attribute as above (the DSA master and +all attached switch ports must be down while doing this). + +It is desirable that all tagging protocols are testable with the ``dsa_loop`` +mockup driver, which can be attached to any network interface. The goal is that +any network interface should be capable of transmitting the same packet in the +same way, and the tagger should decode the same received packet in the same way +regardless of the driver used for the switch control path, and the driver used +for the DSA master. + +The transmission of a packet goes through the tagger's ``xmit`` function. +The passed ``struct sk_buff *skb`` has ``skb->data`` pointing at +``skb_mac_header(skb)``, i.e. at the destination MAC address, and the passed +``struct net_device *dev`` represents the virtual DSA user network interface +whose hardware counterpart the packet must be steered to (i.e. ``swp0``). +The job of this method is to prepare the skb in a way that the switch will +understand what egress port the packet is for (and not deliver it towards other +ports). Typically this is fulfilled by pushing a frame header. Checking for +insufficient size in the skb headroom or tailroom is unnecessary provided that +the ``needed_headroom`` and ``needed_tailroom`` properties were filled out +properly, because DSA ensures there is enough space before calling this method. + +The reception of a packet goes through the tagger's ``rcv`` function. The +passed ``struct sk_buff *skb`` has ``skb->data`` pointing at +``skb_mac_header(skb) + ETH_ALEN`` octets, i.e. to where the first octet after +the EtherType would have been, were this frame not tagged. The role of this +method is to consume the frame header, adjust ``skb->data`` to really point at +the first octet after the EtherType, and to change ``skb->dev`` to point to the +virtual DSA user network interface corresponding to the physical front-facing +switch port that the packet was received on. + +Since tagging protocols in category 1 and 2 break software (and most often also +hardware) packet dissection on the DSA master, features such as RPS (Receive +Packet Steering) on the DSA master would be broken. The DSA framework deals +with this by hooking into the flow dissector and shifting the offset at which +the IP header is to be found in the tagged frame as seen by the DSA master. +This behavior is automatic based on the ``overhead`` value of the tagging +protocol. If not all packets are of equal size, the tagger can implement the +``flow_dissect`` method of the ``struct dsa_device_ops`` and override this +default behavior by specifying the correct offset incurred by each individual +RX packet. Tail taggers do not cause issues to the flow dissector. + +Checksum offload should work with category 1 and 2 taggers when the DSA master +driver declares NETIF_F_HW_CSUM in vlan_features and looks at csum_start and +csum_offset. For those cases, DSA will shift the checksum start and offset by +the tag size. If the DSA master driver still uses the legacy NETIF_F_IP_CSUM +or NETIF_F_IPV6_CSUM in vlan_features, the offload might only work if the +offload hardware already expects that specific tag (perhaps due to matching +vendors). DSA slaves inherit those flags from the master port, and it is up to +the driver to correctly fall back to software checksum when the IP header is not +where the hardware expects. If that check is ineffective, the packets might go +to the network without a proper checksum (the checksum field will have the +pseudo IP header sum). For category 3, when the offload hardware does not +already expect the switch tag in use, the checksum must be calculated before any +tag is inserted (i.e. inside the tagger). Otherwise, the DSA master would +include the tail tag in the (software or hardware) checksum calculation. Then, +when the tag gets stripped by the switch during transmission, it will leave an +incorrect IP checksum in place. + +Due to various reasons (most common being category 1 taggers being associated +with DSA-unaware masters, mangling what the master perceives as MAC DA), the +tagging protocol may require the DSA master to operate in promiscuous mode, to +receive all frames regardless of the value of the MAC DA. This can be done by +setting the ``promisc_on_master`` property of the ``struct dsa_device_ops``. +Note that this assumes a DSA-unaware master driver, which is the norm. + +Master network devices +---------------------- + +Master network devices are regular, unmodified Linux network device drivers for +the CPU/management Ethernet interface. Such a driver might occasionally need to +know whether DSA is enabled (e.g.: to enable/disable specific offload features), +but the DSA subsystem has been proven to work with industry standard drivers: +``e1000e,`` ``mv643xx_eth`` etc. without having to introduce modifications to these +drivers. Such network devices are also often referred to as conduit network +devices since they act as a pipe between the host processor and the hardware +Ethernet switch. + +Networking stack hooks +---------------------- + +When a master netdev is used with DSA, a small hook is placed in the +networking stack is in order to have the DSA subsystem process the Ethernet +switch specific tagging protocol. DSA accomplishes this by registering a +specific (and fake) Ethernet type (later becoming ``skb->protocol``) with the +networking stack, this is also known as a ``ptype`` or ``packet_type``. A typical +Ethernet Frame receive sequence looks like this: + +Master network device (e.g.: e1000e): + +1. Receive interrupt fires: + + - receive function is invoked + - basic packet processing is done: getting length, status etc. + - packet is prepared to be processed by the Ethernet layer by calling + ``eth_type_trans`` + +2. net/ethernet/eth.c:: + + eth_type_trans(skb, dev) + if (dev->dsa_ptr != NULL) + -> skb->protocol = ETH_P_XDSA + +3. drivers/net/ethernet/\*:: + + netif_receive_skb(skb) + -> iterate over registered packet_type + -> invoke handler for ETH_P_XDSA, calls dsa_switch_rcv() + +4. net/dsa/dsa.c:: + + -> dsa_switch_rcv() + -> invoke switch tag specific protocol handler in 'net/dsa/tag_*.c' + +5. net/dsa/tag_*.c: + + - inspect and strip switch tag protocol to determine originating port + - locate per-port network device + - invoke ``eth_type_trans()`` with the DSA slave network device + - invoked ``netif_receive_skb()`` + +Past this point, the DSA slave network devices get delivered regular Ethernet +frames that can be processed by the networking stack. + +Slave network devices +--------------------- + +Slave network devices created by DSA are stacked on top of their master network +device, each of these network interfaces will be responsible for being a +controlling and data-flowing end-point for each front-panel port of the switch. +These interfaces are specialized in order to: + +- insert/remove the switch tag protocol (if it exists) when sending traffic + to/from specific switch ports +- query the switch for ethtool operations: statistics, link state, + Wake-on-LAN, register dumps... +- manage external/internal PHY: link, auto-negotiation, etc. + +These slave network devices have custom net_device_ops and ethtool_ops function +pointers which allow DSA to introduce a level of layering between the networking +stack/ethtool and the switch driver implementation. + +Upon frame transmission from these slave network devices, DSA will look up which +switch tagging protocol is currently registered with these network devices and +invoke a specific transmit routine which takes care of adding the relevant +switch tag in the Ethernet frames. + +These frames are then queued for transmission using the master network device +``ndo_start_xmit()`` function. Since they contain the appropriate switch tag, the +Ethernet switch will be able to process these incoming frames from the +management interface and deliver them to the physical switch port. + +When using multiple CPU ports, it is possible to stack a LAG (bonding/team) +device between the DSA slave devices and the physical DSA masters. The LAG +device is thus also a DSA master, but the LAG slave devices continue to be DSA +masters as well (just with no user port assigned to them; this is needed for +recovery in case the LAG DSA master disappears). Thus, the data path of the LAG +DSA master is used asymmetrically. On RX, the ``ETH_P_XDSA`` handler, which +calls ``dsa_switch_rcv()``, is invoked early (on the physical DSA master; +LAG slave). Therefore, the RX data path of the LAG DSA master is not used. +On the other hand, TX takes place linearly: ``dsa_slave_xmit`` calls +``dsa_enqueue_skb``, which calls ``dev_queue_xmit`` towards the LAG DSA master. +The latter calls ``dev_queue_xmit`` towards one physical DSA master or the +other, and in both cases, the packet exits the system through a hardware path +towards the switch. + +Graphical representation +------------------------ + +Summarized, this is basically how DSA looks like from a network device +perspective:: + + Unaware application + opens and binds socket + | ^ + | | + +-----------v--|--------------------+ + |+------+ +------+ +------+ +------+| + || swp0 | | swp1 | | swp2 | | swp3 || + |+------+-+------+-+------+-+------+| + | DSA switch driver | + +-----------------------------------+ + | ^ + Tag added by | | Tag consumed by + switch driver | | switch driver + v | + +-----------------------------------+ + | Unmodified host interface driver | Software + --------+-----------------------------------+------------ + | Host interface (eth0) | Hardware + +-----------------------------------+ + | ^ + Tag consumed by | | Tag added by + switch hardware | | switch hardware + v | + +-----------------------------------+ + | Switch | + |+------+ +------+ +------+ +------+| + || swp0 | | swp1 | | swp2 | | swp3 || + ++------+-+------+-+------+-+------++ + +Slave MDIO bus +-------------- + +In order to be able to read to/from a switch PHY built into it, DSA creates a +slave MDIO bus which allows a specific switch driver to divert and intercept +MDIO reads/writes towards specific PHY addresses. In most MDIO-connected +switches, these functions would utilize direct or indirect PHY addressing mode +to return standard MII registers from the switch builtin PHYs, allowing the PHY +library and/or to return link status, link partner pages, auto-negotiation +results, etc. + +For Ethernet switches which have both external and internal MDIO buses, the +slave MII bus can be utilized to mux/demux MDIO reads and writes towards either +internal or external MDIO devices this switch might be connected to: internal +PHYs, external PHYs, or even external switches. + +Data structures +--------------- + +DSA data structures are defined in ``include/net/dsa.h`` as well as +``net/dsa/dsa_priv.h``: + +- ``dsa_chip_data``: platform data configuration for a given switch device, + this structure describes a switch device's parent device, its address, as + well as various properties of its ports: names/labels, and finally a routing + table indication (when cascading switches) + +- ``dsa_platform_data``: platform device configuration data which can reference + a collection of dsa_chip_data structures if multiple switches are cascaded, + the master network device this switch tree is attached to needs to be + referenced + +- ``dsa_switch_tree``: structure assigned to the master network device under + ``dsa_ptr``, this structure references a dsa_platform_data structure as well as + the tagging protocol supported by the switch tree, and which receive/transmit + function hooks should be invoked, information about the directly attached + switch is also provided: CPU port. Finally, a collection of dsa_switch are + referenced to address individual switches in the tree. + +- ``dsa_switch``: structure describing a switch device in the tree, referencing + a ``dsa_switch_tree`` as a backpointer, slave network devices, master network + device, and a reference to the backing``dsa_switch_ops`` + +- ``dsa_switch_ops``: structure referencing function pointers, see below for a + full description. + +Design limitations +================== + +Lack of CPU/DSA network devices +------------------------------- + +DSA does not currently create slave network devices for the CPU or DSA ports, as +described before. This might be an issue in the following cases: + +- inability to fetch switch CPU port statistics counters using ethtool, which + can make it harder to debug MDIO switch connected using xMII interfaces + +- inability to configure the CPU port link parameters based on the Ethernet + controller capabilities attached to it: http://patchwork.ozlabs.org/patch/509806/ + +- inability to configure specific VLAN IDs / trunking VLANs between switches + when using a cascaded setup + +Common pitfalls using DSA setups +-------------------------------- + +Once a master network device is configured to use DSA (dev->dsa_ptr becomes +non-NULL), and the switch behind it expects a tagging protocol, this network +interface can only exclusively be used as a conduit interface. Sending packets +directly through this interface (e.g.: opening a socket using this interface) +will not make us go through the switch tagging protocol transmit function, so +the Ethernet switch on the other end, expecting a tag will typically drop this +frame. + +Interactions with other subsystems +================================== + +DSA currently leverages the following subsystems: + +- MDIO/PHY library: ``drivers/net/phy/phy.c``, ``mdio_bus.c`` +- Switchdev:``net/switchdev/*`` +- Device Tree for various of_* functions +- Devlink: ``net/core/devlink.c`` + +MDIO/PHY library +---------------- + +Slave network devices exposed by DSA may or may not be interfacing with PHY +devices (``struct phy_device`` as defined in ``include/linux/phy.h)``, but the DSA +subsystem deals with all possible combinations: + +- internal PHY devices, built into the Ethernet switch hardware +- external PHY devices, connected via an internal or external MDIO bus +- internal PHY devices, connected via an internal MDIO bus +- special, non-autonegotiated or non MDIO-managed PHY devices: SFPs, MoCA; a.k.a + fixed PHYs + +The PHY configuration is done by the ``dsa_slave_phy_setup()`` function and the +logic basically looks like this: + +- if Device Tree is used, the PHY device is looked up using the standard + "phy-handle" property, if found, this PHY device is created and registered + using ``of_phy_connect()`` + +- if Device Tree is used and the PHY device is "fixed", that is, conforms to + the definition of a non-MDIO managed PHY as defined in + ``Documentation/devicetree/bindings/net/fixed-link.txt``, the PHY is registered + and connected transparently using the special fixed MDIO bus driver + +- finally, if the PHY is built into the switch, as is very common with + standalone switch packages, the PHY is probed using the slave MII bus created + by DSA + + +SWITCHDEV +--------- + +DSA directly utilizes SWITCHDEV when interfacing with the bridge layer, and +more specifically with its VLAN filtering portion when configuring VLANs on top +of per-port slave network devices. As of today, the only SWITCHDEV objects +supported by DSA are the FDB and VLAN objects. + +Devlink +------- + +DSA registers one devlink device per physical switch in the fabric. +For each devlink device, every physical port (i.e. user ports, CPU ports, DSA +links or unused ports) is exposed as a devlink port. + +DSA drivers can make use of the following devlink features: + +- Regions: debugging feature which allows user space to dump driver-defined + areas of hardware information in a low-level, binary format. Both global + regions as well as per-port regions are supported. It is possible to export + devlink regions even for pieces of data that are already exposed in some way + to the standard iproute2 user space programs (ip-link, bridge), like address + tables and VLAN tables. For example, this might be useful if the tables + contain additional hardware-specific details which are not visible through + the iproute2 abstraction, or it might be useful to inspect these tables on + the non-user ports too, which are invisible to iproute2 because no network + interface is registered for them. +- Params: a feature which enables user to configure certain low-level tunable + knobs pertaining to the device. Drivers may implement applicable generic + devlink params, or may add new device-specific devlink params. +- Resources: a monitoring feature which enables users to see the degree of + utilization of certain hardware tables in the device, such as FDB, VLAN, etc. +- Shared buffers: a QoS feature for adjusting and partitioning memory and frame + reservations per port and per traffic class, in the ingress and egress + directions, such that low-priority bulk traffic does not impede the + processing of high-priority critical traffic. + +For more details, consult ``Documentation/networking/devlink/``. + +Device Tree +----------- + +DSA features a standardized binding which is documented in +``Documentation/devicetree/bindings/net/dsa/dsa.txt``. PHY/MDIO library helper +functions such as ``of_get_phy_mode()``, ``of_phy_connect()`` are also used to query +per-port PHY specific details: interface connection, MDIO bus location, etc. + +Driver development +================== + +DSA switch drivers need to implement a ``dsa_switch_ops`` structure which will +contain the various members described below. + +Probing, registration and device lifetime +----------------------------------------- + +DSA switches are regular ``device`` structures on buses (be they platform, SPI, +I2C, MDIO or otherwise). The DSA framework is not involved in their probing +with the device core. + +Switch registration from the perspective of a driver means passing a valid +``struct dsa_switch`` pointer to ``dsa_register_switch()``, usually from the +switch driver's probing function. The following members must be valid in the +provided structure: + +- ``ds->dev``: will be used to parse the switch's OF node or platform data. + +- ``ds->num_ports``: will be used to create the port list for this switch, and + to validate the port indices provided in the OF node. + +- ``ds->ops``: a pointer to the ``dsa_switch_ops`` structure holding the DSA + method implementations. + +- ``ds->priv``: backpointer to a driver-private data structure which can be + retrieved in all further DSA method callbacks. + +In addition, the following flags in the ``dsa_switch`` structure may optionally +be configured to obtain driver-specific behavior from the DSA core. Their +behavior when set is documented through comments in ``include/net/dsa.h``. + +- ``ds->vlan_filtering_is_global`` + +- ``ds->needs_standalone_vlan_filtering`` + +- ``ds->configure_vlan_while_not_filtering`` + +- ``ds->untag_bridge_pvid`` + +- ``ds->assisted_learning_on_cpu_port`` + +- ``ds->mtu_enforcement_ingress`` + +- ``ds->fdb_isolation`` + +Internally, DSA keeps an array of switch trees (group of switches) global to +the kernel, and attaches a ``dsa_switch`` structure to a tree on registration. +The tree ID to which the switch is attached is determined by the first u32 +number of the ``dsa,member`` property of the switch's OF node (0 if missing). +The switch ID within the tree is determined by the second u32 number of the +same OF property (0 if missing). Registering multiple switches with the same +switch ID and tree ID is illegal and will cause an error. Using platform data, +a single switch and a single switch tree is permitted. + +In case of a tree with multiple switches, probing takes place asymmetrically. +The first N-1 callers of ``dsa_register_switch()`` only add their ports to the +port list of the tree (``dst->ports``), each port having a backpointer to its +associated switch (``dp->ds``). Then, these switches exit their +``dsa_register_switch()`` call early, because ``dsa_tree_setup_routing_table()`` +has determined that the tree is not yet complete (not all ports referenced by +DSA links are present in the tree's port list). The tree becomes complete when +the last switch calls ``dsa_register_switch()``, and this triggers the effective +continuation of initialization (including the call to ``ds->ops->setup()``) for +all switches within that tree, all as part of the calling context of the last +switch's probe function. + +The opposite of registration takes place when calling ``dsa_unregister_switch()``, +which removes a switch's ports from the port list of the tree. The entire tree +is torn down when the first switch unregisters. + +It is mandatory for DSA switch drivers to implement the ``shutdown()`` callback +of their respective bus, and call ``dsa_switch_shutdown()`` from it (a minimal +version of the full teardown performed by ``dsa_unregister_switch()``). +The reason is that DSA keeps a reference on the master net device, and if the +driver for the master device decides to unbind on shutdown, DSA's reference +will block that operation from finalizing. + +Either ``dsa_switch_shutdown()`` or ``dsa_unregister_switch()`` must be called, +but not both, and the device driver model permits the bus' ``remove()`` method +to be called even if ``shutdown()`` was already called. Therefore, drivers are +expected to implement a mutual exclusion method between ``remove()`` and +``shutdown()`` by setting their drvdata to NULL after any of these has run, and +checking whether the drvdata is NULL before proceeding to take any action. + +After ``dsa_switch_shutdown()`` or ``dsa_unregister_switch()`` was called, no +further callbacks via the provided ``dsa_switch_ops`` may take place, and the +driver may free the data structures associated with the ``dsa_switch``. + +Switch configuration +-------------------- + +- ``get_tag_protocol``: this is to indicate what kind of tagging protocol is + supported, should be a valid value from the ``dsa_tag_protocol`` enum. + The returned information does not have to be static; the driver is passed the + CPU port number, as well as the tagging protocol of a possibly stacked + upstream switch, in case there are hardware limitations in terms of supported + tag formats. + +- ``change_tag_protocol``: when the default tagging protocol has compatibility + problems with the master or other issues, the driver may support changing it + at runtime, either through a device tree property or through sysfs. In that + case, further calls to ``get_tag_protocol`` should report the protocol in + current use. + +- ``setup``: setup function for the switch, this function is responsible for setting + up the ``dsa_switch_ops`` private structure with all it needs: register maps, + interrupts, mutexes, locks, etc. This function is also expected to properly + configure the switch to separate all network interfaces from each other, that + is, they should be isolated by the switch hardware itself, typically by creating + a Port-based VLAN ID for each port and allowing only the CPU port and the + specific port to be in the forwarding vector. Ports that are unused by the + platform should be disabled. Past this function, the switch is expected to be + fully configured and ready to serve any kind of request. It is recommended + to issue a software reset of the switch during this setup function in order to + avoid relying on what a previous software agent such as a bootloader/firmware + may have previously configured. The method responsible for undoing any + applicable allocations or operations done here is ``teardown``. + +- ``port_setup`` and ``port_teardown``: methods for initialization and + destruction of per-port data structures. It is mandatory for some operations + such as registering and unregistering devlink port regions to be done from + these methods, otherwise they are optional. A port will be torn down only if + it has been previously set up. It is possible for a port to be set up during + probing only to be torn down immediately afterwards, for example in case its + PHY cannot be found. In this case, probing of the DSA switch continues + without that particular port. + +- ``port_change_master``: method through which the affinity (association used + for traffic termination purposes) between a user port and a CPU port can be + changed. By default all user ports from a tree are assigned to the first + available CPU port that makes sense for them (most of the times this means + the user ports of a tree are all assigned to the same CPU port, except for H + topologies as described in commit 2c0b03258b8b). The ``port`` argument + represents the index of the user port, and the ``master`` argument represents + the new DSA master ``net_device``. The CPU port associated with the new + master can be retrieved by looking at ``struct dsa_port *cpu_dp = + master->dsa_ptr``. Additionally, the master can also be a LAG device where + all the slave devices are physical DSA masters. LAG DSA masters also have a + valid ``master->dsa_ptr`` pointer, however this is not unique, but rather a + duplicate of the first physical DSA master's (LAG slave) ``dsa_ptr``. In case + of a LAG DSA master, a further call to ``port_lag_join`` will be emitted + separately for the physical CPU ports associated with the physical DSA + masters, requesting them to create a hardware LAG associated with the LAG + interface. + +PHY devices and link management +------------------------------- + +- ``get_phy_flags``: Some switches are interfaced to various kinds of Ethernet PHYs, + if the PHY library PHY driver needs to know about information it cannot obtain + on its own (e.g.: coming from switch memory mapped registers), this function + should return a 32-bit bitmask of "flags" that is private between the switch + driver and the Ethernet PHY driver in ``drivers/net/phy/\*``. + +- ``phy_read``: Function invoked by the DSA slave MDIO bus when attempting to read + the switch port MDIO registers. If unavailable, return 0xffff for each read. + For builtin switch Ethernet PHYs, this function should allow reading the link + status, auto-negotiation results, link partner pages, etc. + +- ``phy_write``: Function invoked by the DSA slave MDIO bus when attempting to write + to the switch port MDIO registers. If unavailable return a negative error + code. + +- ``adjust_link``: Function invoked by the PHY library when a slave network device + is attached to a PHY device. This function is responsible for appropriately + configuring the switch port link parameters: speed, duplex, pause based on + what the ``phy_device`` is providing. + +- ``fixed_link_update``: Function invoked by the PHY library, and specifically by + the fixed PHY driver asking the switch driver for link parameters that could + not be auto-negotiated, or obtained by reading the PHY registers through MDIO. + This is particularly useful for specific kinds of hardware such as QSGMII, + MoCA or other kinds of non-MDIO managed PHYs where out of band link + information is obtained + +Ethtool operations +------------------ + +- ``get_strings``: ethtool function used to query the driver's strings, will + typically return statistics strings, private flags strings, etc. + +- ``get_ethtool_stats``: ethtool function used to query per-port statistics and + return their values. DSA overlays slave network devices general statistics: + RX/TX counters from the network device, with switch driver specific statistics + per port + +- ``get_sset_count``: ethtool function used to query the number of statistics items + +- ``get_wol``: ethtool function used to obtain Wake-on-LAN settings per-port, this + function may for certain implementations also query the master network device + Wake-on-LAN settings if this interface needs to participate in Wake-on-LAN + +- ``set_wol``: ethtool function used to configure Wake-on-LAN settings per-port, + direct counterpart to set_wol with similar restrictions + +- ``set_eee``: ethtool function which is used to configure a switch port EEE (Green + Ethernet) settings, can optionally invoke the PHY library to enable EEE at the + PHY level if relevant. This function should enable EEE at the switch port MAC + controller and data-processing logic + +- ``get_eee``: ethtool function which is used to query a switch port EEE settings, + this function should return the EEE state of the switch port MAC controller + and data-processing logic as well as query the PHY for its currently configured + EEE settings + +- ``get_eeprom_len``: ethtool function returning for a given switch the EEPROM + length/size in bytes + +- ``get_eeprom``: ethtool function returning for a given switch the EEPROM contents + +- ``set_eeprom``: ethtool function writing specified data to a given switch EEPROM + +- ``get_regs_len``: ethtool function returning the register length for a given + switch + +- ``get_regs``: ethtool function returning the Ethernet switch internal register + contents. This function might require user-land code in ethtool to + pretty-print register values and registers + +Power management +---------------- + +- ``suspend``: function invoked by the DSA platform device when the system goes to + suspend, should quiesce all Ethernet switch activities, but keep ports + participating in Wake-on-LAN active as well as additional wake-up logic if + supported + +- ``resume``: function invoked by the DSA platform device when the system resumes, + should resume all Ethernet switch activities and re-configure the switch to be + in a fully active state + +- ``port_enable``: function invoked by the DSA slave network device ndo_open + function when a port is administratively brought up, this function should + fully enable a given switch port. DSA takes care of marking the port with + ``BR_STATE_BLOCKING`` if the port is a bridge member, or ``BR_STATE_FORWARDING`` if it + was not, and propagating these changes down to the hardware + +- ``port_disable``: function invoked by the DSA slave network device ndo_close + function when a port is administratively brought down, this function should + fully disable a given switch port. DSA takes care of marking the port with + ``BR_STATE_DISABLED`` and propagating changes to the hardware if this port is + disabled while being a bridge member + +Address databases +----------------- + +Switching hardware is expected to have a table for FDB entries, however not all +of them are active at the same time. An address database is the subset (partition) +of FDB entries that is active (can be matched by address learning on RX, or FDB +lookup on TX) depending on the state of the port. An address database may +occasionally be called "FID" (Filtering ID) in this document, although the +underlying implementation may choose whatever is available to the hardware. + +For example, all ports that belong to a VLAN-unaware bridge (which is +*currently* VLAN-unaware) are expected to learn source addresses in the +database associated by the driver with that bridge (and not with other +VLAN-unaware bridges). During forwarding and FDB lookup, a packet received on a +VLAN-unaware bridge port should be able to find a VLAN-unaware FDB entry having +the same MAC DA as the packet, which is present on another port member of the +same bridge. At the same time, the FDB lookup process must be able to not find +an FDB entry having the same MAC DA as the packet, if that entry points towards +a port which is a member of a different VLAN-unaware bridge (and is therefore +associated with a different address database). + +Similarly, each VLAN of each offloaded VLAN-aware bridge should have an +associated address database, which is shared by all ports which are members of +that VLAN, but not shared by ports belonging to different bridges that are +members of the same VID. + +In this context, a VLAN-unaware database means that all packets are expected to +match on it irrespective of VLAN ID (only MAC address lookup), whereas a +VLAN-aware database means that packets are supposed to match based on the VLAN +ID from the classified 802.1Q header (or the pvid if untagged). + +At the bridge layer, VLAN-unaware FDB entries have the special VID value of 0, +whereas VLAN-aware FDB entries have non-zero VID values. Note that a +VLAN-unaware bridge may have VLAN-aware (non-zero VID) FDB entries, and a +VLAN-aware bridge may have VLAN-unaware FDB entries. As in hardware, the +software bridge keeps separate address databases, and offloads to hardware the +FDB entries belonging to these databases, through switchdev, asynchronously +relative to the moment when the databases become active or inactive. + +When a user port operates in standalone mode, its driver should configure it to +use a separate database called a port private database. This is different from +the databases described above, and should impede operation as standalone port +(packet in, packet out to the CPU port) as little as possible. For example, +on ingress, it should not attempt to learn the MAC SA of ingress traffic, since +learning is a bridging layer service and this is a standalone port, therefore +it would consume useless space. With no address learning, the port private +database should be empty in a naive implementation, and in this case, all +received packets should be trivially flooded to the CPU port. + +DSA (cascade) and CPU ports are also called "shared" ports because they service +multiple address databases, and the database that a packet should be associated +to is usually embedded in the DSA tag. This means that the CPU port may +simultaneously transport packets coming from a standalone port (which were +classified by hardware in one address database), and from a bridge port (which +were classified to a different address database). + +Switch drivers which satisfy certain criteria are able to optimize the naive +configuration by removing the CPU port from the flooding domain of the switch, +and just program the hardware with FDB entries pointing towards the CPU port +for which it is known that software is interested in those MAC addresses. +Packets which do not match a known FDB entry will not be delivered to the CPU, +which will save CPU cycles required for creating an skb just to drop it. + +DSA is able to perform host address filtering for the following kinds of +addresses: + +- Primary unicast MAC addresses of ports (``dev->dev_addr``). These are + associated with the port private database of the respective user port, + and the driver is notified to install them through ``port_fdb_add`` towards + the CPU port. + +- Secondary unicast and multicast MAC addresses of ports (addresses added + through ``dev_uc_add()`` and ``dev_mc_add()``). These are also associated + with the port private database of the respective user port. + +- Local/permanent bridge FDB entries (``BR_FDB_LOCAL``). These are the MAC + addresses of the bridge ports, for which packets must be terminated locally + and not forwarded. They are associated with the address database for that + bridge. + +- Static bridge FDB entries installed towards foreign (non-DSA) interfaces + present in the same bridge as some DSA switch ports. These are also + associated with the address database for that bridge. + +- Dynamically learned FDB entries on foreign interfaces present in the same + bridge as some DSA switch ports, only if ``ds->assisted_learning_on_cpu_port`` + is set to true by the driver. These are associated with the address database + for that bridge. + +For various operations detailed below, DSA provides a ``dsa_db`` structure +which can be of the following types: + +- ``DSA_DB_PORT``: the FDB (or MDB) entry to be installed or deleted belongs to + the port private database of user port ``db->dp``. +- ``DSA_DB_BRIDGE``: the entry belongs to one of the address databases of bridge + ``db->bridge``. Separation between the VLAN-unaware database and the per-VID + databases of this bridge is expected to be done by the driver. +- ``DSA_DB_LAG``: the entry belongs to the address database of LAG ``db->lag``. + Note: ``DSA_DB_LAG`` is currently unused and may be removed in the future. + +The drivers which act upon the ``dsa_db`` argument in ``port_fdb_add``, +``port_mdb_add`` etc should declare ``ds->fdb_isolation`` as true. + +DSA associates each offloaded bridge and each offloaded LAG with a one-based ID +(``struct dsa_bridge :: num``, ``struct dsa_lag :: id``) for the purposes of +refcounting addresses on shared ports. Drivers may piggyback on DSA's numbering +scheme (the ID is readable through ``db->bridge.num`` and ``db->lag.id`` or may +implement their own. + +Only the drivers which declare support for FDB isolation are notified of FDB +entries on the CPU port belonging to ``DSA_DB_PORT`` databases. +For compatibility/legacy reasons, ``DSA_DB_BRIDGE`` addresses are notified to +drivers even if they do not support FDB isolation. However, ``db->bridge.num`` +and ``db->lag.id`` are always set to 0 in that case (to denote the lack of +isolation, for refcounting purposes). + +Note that it is not mandatory for a switch driver to implement physically +separate address databases for each standalone user port. Since FDB entries in +the port private databases will always point to the CPU port, there is no risk +for incorrect forwarding decisions. In this case, all standalone ports may +share the same database, but the reference counting of host-filtered addresses +(not deleting the FDB entry for a port's MAC address if it's still in use by +another port) becomes the responsibility of the driver, because DSA is unaware +that the port databases are in fact shared. This can be achieved by calling +``dsa_fdb_present_in_other_db()`` and ``dsa_mdb_present_in_other_db()``. +The down side is that the RX filtering lists of each user port are in fact +shared, which means that user port A may accept a packet with a MAC DA it +shouldn't have, only because that MAC address was in the RX filtering list of +user port B. These packets will still be dropped in software, however. + +Bridge layer +------------ + +Offloading the bridge forwarding plane is optional and handled by the methods +below. They may be absent, return -EOPNOTSUPP, or ``ds->max_num_bridges`` may +be non-zero and exceeded, and in this case, joining a bridge port is still +possible, but the packet forwarding will take place in software, and the ports +under a software bridge must remain configured in the same way as for +standalone operation, i.e. have all bridging service functions (address +learning etc) disabled, and send all received packets to the CPU port only. + +Concretely, a port starts offloading the forwarding plane of a bridge once it +returns success to the ``port_bridge_join`` method, and stops doing so after +``port_bridge_leave`` has been called. Offloading the bridge means autonomously +learning FDB entries in accordance with the software bridge port's state, and +autonomously forwarding (or flooding) received packets without CPU intervention. +This is optional even when offloading a bridge port. Tagging protocol drivers +are expected to call ``dsa_default_offload_fwd_mark(skb)`` for packets which +have already been autonomously forwarded in the forwarding domain of the +ingress switch port. DSA, through ``dsa_port_devlink_setup()``, considers all +switch ports part of the same tree ID to be part of the same bridge forwarding +domain (capable of autonomous forwarding to each other). + +Offloading the TX forwarding process of a bridge is a distinct concept from +simply offloading its forwarding plane, and refers to the ability of certain +driver and tag protocol combinations to transmit a single skb coming from the +bridge device's transmit function to potentially multiple egress ports (and +thereby avoid its cloning in software). + +Packets for which the bridge requests this behavior are called data plane +packets and have ``skb->offload_fwd_mark`` set to true in the tag protocol +driver's ``xmit`` function. Data plane packets are subject to FDB lookup, +hardware learning on the CPU port, and do not override the port STP state. +Additionally, replication of data plane packets (multicast, flooding) is +handled in hardware and the bridge driver will transmit a single skb for each +packet that may or may not need replication. + +When the TX forwarding offload is enabled, the tag protocol driver is +responsible to inject packets into the data plane of the hardware towards the +correct bridging domain (FID) that the port is a part of. The port may be +VLAN-unaware, and in this case the FID must be equal to the FID used by the +driver for its VLAN-unaware address database associated with that bridge. +Alternatively, the bridge may be VLAN-aware, and in that case, it is guaranteed +that the packet is also VLAN-tagged with the VLAN ID that the bridge processed +this packet in. It is the responsibility of the hardware to untag the VID on +the egress-untagged ports, or keep the tag on the egress-tagged ones. + +- ``port_bridge_join``: bridge layer function invoked when a given switch port is + added to a bridge, this function should do what's necessary at the switch + level to permit the joining port to be added to the relevant logical + domain for it to ingress/egress traffic with other members of the bridge. + By setting the ``tx_fwd_offload`` argument to true, the TX forwarding process + of this bridge is also offloaded. + +- ``port_bridge_leave``: bridge layer function invoked when a given switch port is + removed from a bridge, this function should do what's necessary at the + switch level to deny the leaving port from ingress/egress traffic from the + remaining bridge members. + +- ``port_stp_state_set``: bridge layer function invoked when a given switch port STP + state is computed by the bridge layer and should be propagated to switch + hardware to forward/block/learn traffic. + +- ``port_bridge_flags``: bridge layer function invoked when a port must + configure its settings for e.g. flooding of unknown traffic or source address + learning. The switch driver is responsible for initial setup of the + standalone ports with address learning disabled and egress flooding of all + types of traffic, then the DSA core notifies of any change to the bridge port + flags when the port joins and leaves a bridge. DSA does not currently manage + the bridge port flags for the CPU port. The assumption is that address + learning should be statically enabled (if supported by the hardware) on the + CPU port, and flooding towards the CPU port should also be enabled, due to a + lack of an explicit address filtering mechanism in the DSA core. + +- ``port_fast_age``: bridge layer function invoked when flushing the + dynamically learned FDB entries on the port is necessary. This is called when + transitioning from an STP state where learning should take place to an STP + state where it shouldn't, or when leaving a bridge, or when address learning + is turned off via ``port_bridge_flags``. + +Bridge VLAN filtering +--------------------- + +- ``port_vlan_filtering``: bridge layer function invoked when the bridge gets + configured for turning on or off VLAN filtering. If nothing specific needs to + be done at the hardware level, this callback does not need to be implemented. + When VLAN filtering is turned on, the hardware must be programmed with + rejecting 802.1Q frames which have VLAN IDs outside of the programmed allowed + VLAN ID map/rules. If there is no PVID programmed into the switch port, + untagged frames must be rejected as well. When turned off the switch must + accept any 802.1Q frames irrespective of their VLAN ID, and untagged frames are + allowed. + +- ``port_vlan_add``: bridge layer function invoked when a VLAN is configured + (tagged or untagged) for the given switch port. The CPU port becomes a member + of a VLAN only if a foreign bridge port is also a member of it (and + forwarding needs to take place in software), or the VLAN is installed to the + VLAN group of the bridge device itself, for termination purposes + (``bridge vlan add dev br0 vid 100 self``). VLANs on shared ports are + reference counted and removed when there is no user left. Drivers do not need + to manually install a VLAN on the CPU port. + +- ``port_vlan_del``: bridge layer function invoked when a VLAN is removed from the + given switch port + +- ``port_fdb_add``: bridge layer function invoked when the bridge wants to install a + Forwarding Database entry, the switch hardware should be programmed with the + specified address in the specified VLAN Id in the forwarding database + associated with this VLAN ID. + +- ``port_fdb_del``: bridge layer function invoked when the bridge wants to remove a + Forwarding Database entry, the switch hardware should be programmed to delete + the specified MAC address from the specified VLAN ID if it was mapped into + this port forwarding database + +- ``port_fdb_dump``: bridge bypass function invoked by ``ndo_fdb_dump`` on the + physical DSA port interfaces. Since DSA does not attempt to keep in sync its + hardware FDB entries with the software bridge, this method is implemented as + a means to view the entries visible on user ports in the hardware database. + The entries reported by this function have the ``self`` flag in the output of + the ``bridge fdb show`` command. + +- ``port_mdb_add``: bridge layer function invoked when the bridge wants to install + a multicast database entry. The switch hardware should be programmed with the + specified address in the specified VLAN ID in the forwarding database + associated with this VLAN ID. + +- ``port_mdb_del``: bridge layer function invoked when the bridge wants to remove a + multicast database entry, the switch hardware should be programmed to delete + the specified MAC address from the specified VLAN ID if it was mapped into + this port forwarding database. + +Link aggregation +---------------- + +Link aggregation is implemented in the Linux networking stack by the bonding +and team drivers, which are modeled as virtual, stackable network interfaces. +DSA is capable of offloading a link aggregation group (LAG) to hardware that +supports the feature, and supports bridging between physical ports and LAGs, +as well as between LAGs. A bonding/team interface which holds multiple physical +ports constitutes a logical port, although DSA has no explicit concept of a +logical port at the moment. Due to this, events where a LAG joins/leaves a +bridge are treated as if all individual physical ports that are members of that +LAG join/leave the bridge. Switchdev port attributes (VLAN filtering, STP +state, etc) and objects (VLANs, MDB entries) offloaded to a LAG as bridge port +are treated similarly: DSA offloads the same switchdev object / port attribute +on all members of the LAG. Static bridge FDB entries on a LAG are not yet +supported, since the DSA driver API does not have the concept of a logical port +ID. + +- ``port_lag_join``: function invoked when a given switch port is added to a + LAG. The driver may return ``-EOPNOTSUPP``, and in this case, DSA will fall + back to a software implementation where all traffic from this port is sent to + the CPU. +- ``port_lag_leave``: function invoked when a given switch port leaves a LAG + and returns to operation as a standalone port. +- ``port_lag_change``: function invoked when the link state of any member of + the LAG changes, and the hashing function needs rebalancing to only make use + of the subset of physical LAG member ports that are up. + +Drivers that benefit from having an ID associated with each offloaded LAG +can optionally populate ``ds->num_lag_ids`` from the ``dsa_switch_ops::setup`` +method. The LAG ID associated with a bonding/team interface can then be +retrieved by a DSA switch driver using the ``dsa_lag_id`` function. + +IEC 62439-2 (MRP) +----------------- + +The Media Redundancy Protocol is a topology management protocol optimized for +fast fault recovery time for ring networks, which has some components +implemented as a function of the bridge driver. MRP uses management PDUs +(Test, Topology, LinkDown/Up, Option) sent at a multicast destination MAC +address range of 01:15:4e:00:00:0x and with an EtherType of 0x88e3. +Depending on the node's role in the ring (MRM: Media Redundancy Manager, +MRC: Media Redundancy Client, MRA: Media Redundancy Automanager), certain MRP +PDUs might need to be terminated locally and others might need to be forwarded. +An MRM might also benefit from offloading to hardware the creation and +transmission of certain MRP PDUs (Test). + +Normally an MRP instance can be created on top of any network interface, +however in the case of a device with an offloaded data path such as DSA, it is +necessary for the hardware, even if it is not MRP-aware, to be able to extract +the MRP PDUs from the fabric before the driver can proceed with the software +implementation. DSA today has no driver which is MRP-aware, therefore it only +listens for the bare minimum switchdev objects required for the software assist +to work properly. The operations are detailed below. + +- ``port_mrp_add`` and ``port_mrp_del``: notifies driver when an MRP instance + with a certain ring ID, priority, primary port and secondary port is + created/deleted. +- ``port_mrp_add_ring_role`` and ``port_mrp_del_ring_role``: function invoked + when an MRP instance changes ring roles between MRM or MRC. This affects + which MRP PDUs should be trapped to software and which should be autonomously + forwarded. + +IEC 62439-3 (HSR/PRP) +--------------------- + +The Parallel Redundancy Protocol (PRP) is a network redundancy protocol which +works by duplicating and sequence numbering packets through two independent L2 +networks (which are unaware of the PRP tail tags carried in the packets), and +eliminating the duplicates at the receiver. The High-availability Seamless +Redundancy (HSR) protocol is similar in concept, except all nodes that carry +the redundant traffic are aware of the fact that it is HSR-tagged (because HSR +uses a header with an EtherType of 0x892f) and are physically connected in a +ring topology. Both HSR and PRP use supervision frames for monitoring the +health of the network and for discovery of other nodes. + +In Linux, both HSR and PRP are implemented in the hsr driver, which +instantiates a virtual, stackable network interface with two member ports. +The driver only implements the basic roles of DANH (Doubly Attached Node +implementing HSR) and DANP (Doubly Attached Node implementing PRP); the roles +of RedBox and QuadBox are not implemented (therefore, bridging a hsr network +interface with a physical switch port does not produce the expected result). + +A driver which is able of offloading certain functions of a DANP or DANH should +declare the corresponding netdev features as indicated by the documentation at +``Documentation/networking/netdev-features.rst``. Additionally, the following +methods must be implemented: + +- ``port_hsr_join``: function invoked when a given switch port is added to a + DANP/DANH. The driver may return ``-EOPNOTSUPP`` and in this case, DSA will + fall back to a software implementation where all traffic from this port is + sent to the CPU. +- ``port_hsr_leave``: function invoked when a given switch port leaves a + DANP/DANH and returns to normal operation as a standalone port. + +TODO +==== + +Making SWITCHDEV and DSA converge towards an unified codebase +------------------------------------------------------------- + +SWITCHDEV properly takes care of abstracting the networking stack with offload +capable hardware, but does not enforce a strict switch device driver model. On +the other DSA enforces a fairly strict device driver model, and deals with most +of the switch specific. At some point we should envision a merger between these +two subsystems and get the best of both worlds. diff --git a/Documentation/networking/dsa/index.rst b/Documentation/networking/dsa/index.rst new file mode 100644 index 0000000000..ee631e2d64 --- /dev/null +++ b/Documentation/networking/dsa/index.rst @@ -0,0 +1,13 @@ +=============================== +Distributed Switch Architecture +=============================== + +.. toctree:: + :maxdepth: 1 + + dsa + b53 + bcm_sf2 + lan9303 + sja1105 + configuration diff --git a/Documentation/networking/dsa/lan9303.rst b/Documentation/networking/dsa/lan9303.rst new file mode 100644 index 0000000000..e3c820db28 --- /dev/null +++ b/Documentation/networking/dsa/lan9303.rst @@ -0,0 +1,37 @@ +============================== +LAN9303 Ethernet switch driver +============================== + +The LAN9303 is a three port 10/100 Mbps ethernet switch with integrated phys for +the two external ethernet ports. The third port is an RMII/MII interface to a +host master network interface (e.g. fixed link). + + +Driver details +============== + +The driver is implemented as a DSA driver, see ``Documentation/networking/dsa/dsa.rst``. + +See ``Documentation/devicetree/bindings/net/dsa/lan9303.txt`` for device tree +binding. + +The LAN9303 can be managed both via MDIO and I2C, both supported by this driver. + +At startup the driver configures the device to provide two separate network +interfaces (which is the default state of a DSA device). Due to HW limitations, +no HW MAC learning takes place in this mode. + +When both user ports are joined to the same bridge, the normal HW MAC learning +is enabled. This means that unicast traffic is forwarded in HW. Broadcast and +multicast is flooded in HW. STP is also supported in this mode. The driver +support fdb/mdb operations as well, meaning IGMP snooping is supported. + +If one of the user ports leave the bridge, the ports goes back to the initial +separated operation. + + +Driver limitations +================== + + - Support for VLAN filtering is not implemented + - The HW does not support VLAN-specific fdb entries diff --git a/Documentation/networking/dsa/sja1105.rst b/Documentation/networking/dsa/sja1105.rst new file mode 100644 index 0000000000..e0219c1452 --- /dev/null +++ b/Documentation/networking/dsa/sja1105.rst @@ -0,0 +1,445 @@ +========================= +NXP SJA1105 switch driver +========================= + +Overview +======== + +The NXP SJA1105 is a family of 10 SPI-managed automotive switches: + +- SJA1105E: First generation, no TTEthernet +- SJA1105T: First generation, TTEthernet +- SJA1105P: Second generation, no TTEthernet, no SGMII +- SJA1105Q: Second generation, TTEthernet, no SGMII +- SJA1105R: Second generation, no TTEthernet, SGMII +- SJA1105S: Second generation, TTEthernet, SGMII +- SJA1110A: Third generation, TTEthernet, SGMII, integrated 100base-T1 and + 100base-TX PHYs +- SJA1110B: Third generation, TTEthernet, SGMII, 100base-T1, 100base-TX +- SJA1110C: Third generation, TTEthernet, SGMII, 100base-T1, 100base-TX +- SJA1110D: Third generation, TTEthernet, SGMII, 100base-T1 + +Being automotive parts, their configuration interface is geared towards +set-and-forget use, with minimal dynamic interaction at runtime. They +require a static configuration to be composed by software and packed +with CRC and table headers, and sent over SPI. + +The static configuration is composed of several configuration tables. Each +table takes a number of entries. Some configuration tables can be (partially) +reconfigured at runtime, some not. Some tables are mandatory, some not: + +============================= ================== ============================= +Table Mandatory Reconfigurable +============================= ================== ============================= +Schedule no no +Schedule entry points if Scheduling no +VL Lookup no no +VL Policing if VL Lookup no +VL Forwarding if VL Lookup no +L2 Lookup no no +L2 Policing yes no +VLAN Lookup yes yes +L2 Forwarding yes partially (fully on P/Q/R/S) +MAC Config yes partially (fully on P/Q/R/S) +Schedule Params if Scheduling no +Schedule Entry Points Params if Scheduling no +VL Forwarding Params if VL Forwarding no +L2 Lookup Params no partially (fully on P/Q/R/S) +L2 Forwarding Params yes no +Clock Sync Params no no +AVB Params no no +General Params yes partially +Retagging no yes +xMII Params yes no +SGMII no yes +============================= ================== ============================= + + +Also the configuration is write-only (software cannot read it back from the +switch except for very few exceptions). + +The driver creates a static configuration at probe time, and keeps it at +all times in memory, as a shadow for the hardware state. When required to +change a hardware setting, the static configuration is also updated. +If that changed setting can be transmitted to the switch through the dynamic +reconfiguration interface, it is; otherwise the switch is reset and +reprogrammed with the updated static configuration. + +Switching features +================== + +The driver supports the configuration of L2 forwarding rules in hardware for +port bridging. The forwarding, broadcast and flooding domain between ports can +be restricted through two methods: either at the L2 forwarding level (isolate +one bridge's ports from another's) or at the VLAN port membership level +(isolate ports within the same bridge). The final forwarding decision taken by +the hardware is a logical AND of these two sets of rules. + +The hardware tags all traffic internally with a port-based VLAN (pvid), or it +decodes the VLAN information from the 802.1Q tag. Advanced VLAN classification +is not possible. Once attributed a VLAN tag, frames are checked against the +port's membership rules and dropped at ingress if they don't match any VLAN. +This behavior is available when switch ports are enslaved to a bridge with +``vlan_filtering 1``. + +Normally the hardware is not configurable with respect to VLAN awareness, but +by changing what TPID the switch searches 802.1Q tags for, the semantics of a +bridge with ``vlan_filtering 0`` can be kept (accept all traffic, tagged or +untagged), and therefore this mode is also supported. + +Segregating the switch ports in multiple bridges is supported (e.g. 2 + 2), but +all bridges should have the same level of VLAN awareness (either both have +``vlan_filtering`` 0, or both 1). + +Topology and loop detection through STP is supported. + +Offloads +======== + +Time-aware scheduling +--------------------- + +The switch supports a variation of the enhancements for scheduled traffic +specified in IEEE 802.1Q-2018 (formerly 802.1Qbv). This means it can be used to +ensure deterministic latency for priority traffic that is sent in-band with its +gate-open event in the network schedule. + +This capability can be managed through the tc-taprio offload ('flags 2'). The +difference compared to the software implementation of taprio is that the latter +would only be able to shape traffic originated from the CPU, but not +autonomously forwarded flows. + +The device has 8 traffic classes, and maps incoming frames to one of them based +on the VLAN PCP bits (if no VLAN is present, the port-based default is used). +As described in the previous sections, depending on the value of +``vlan_filtering``, the EtherType recognized by the switch as being VLAN can +either be the typical 0x8100 or a custom value used internally by the driver +for tagging. Therefore, the switch ignores the VLAN PCP if used in standalone +or bridge mode with ``vlan_filtering=0``, as it will not recognize the 0x8100 +EtherType. In these modes, injecting into a particular TX queue can only be +done by the DSA net devices, which populate the PCP field of the tagging header +on egress. Using ``vlan_filtering=1``, the behavior is the other way around: +offloaded flows can be steered to TX queues based on the VLAN PCP, but the DSA +net devices are no longer able to do that. To inject frames into a hardware TX +queue with VLAN awareness active, it is necessary to create a VLAN +sub-interface on the DSA master port, and send normal (0x8100) VLAN-tagged +towards the switch, with the VLAN PCP bits set appropriately. + +Management traffic (having DMAC 01-80-C2-xx-xx-xx or 01-19-1B-xx-xx-xx) is the +notable exception: the switch always treats it with a fixed priority and +disregards any VLAN PCP bits even if present. The traffic class for management +traffic has a value of 7 (highest priority) at the moment, which is not +configurable in the driver. + +Below is an example of configuring a 500 us cyclic schedule on egress port +``swp5``. The traffic class gate for management traffic (7) is open for 100 us, +and the gates for all other traffic classes are open for 400 us:: + + #!/bin/bash + + set -e -u -o pipefail + + NSEC_PER_SEC="1000000000" + + gatemask() { + local tc_list="$1" + local mask=0 + + for tc in ${tc_list}; do + mask=$((${mask} | (1 << ${tc}))) + done + + printf "%02x" ${mask} + } + + if ! systemctl is-active --quiet ptp4l; then + echo "Please start the ptp4l service" + exit + fi + + now=$(phc_ctl /dev/ptp1 get | gawk '/clock time is/ { print $5; }') + # Phase-align the base time to the start of the next second. + sec=$(echo "${now}" | gawk -F. '{ print $1; }') + base_time="$(((${sec} + 1) * ${NSEC_PER_SEC}))" + + tc qdisc add dev swp5 parent root handle 100 taprio \ + num_tc 8 \ + map 0 1 2 3 5 6 7 \ + queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 \ + base-time ${base_time} \ + sched-entry S $(gatemask 7) 100000 \ + sched-entry S $(gatemask "0 1 2 3 4 5 6") 400000 \ + flags 2 + +It is possible to apply the tc-taprio offload on multiple egress ports. There +are hardware restrictions related to the fact that no gate event may trigger +simultaneously on two ports. The driver checks the consistency of the schedules +against this restriction and errors out when appropriate. Schedule analysis is +needed to avoid this, which is outside the scope of the document. + +Routing actions (redirect, trap, drop) +-------------------------------------- + +The switch is able to offload flow-based redirection of packets to a set of +destination ports specified by the user. Internally, this is implemented by +making use of Virtual Links, a TTEthernet concept. + +The driver supports 2 types of keys for Virtual Links: + +- VLAN-aware virtual links: these match on destination MAC address, VLAN ID and + VLAN PCP. +- VLAN-unaware virtual links: these match on destination MAC address only. + +The VLAN awareness state of the bridge (vlan_filtering) cannot be changed while +there are virtual link rules installed. + +Composing multiple actions inside the same rule is supported. When only routing +actions are requested, the driver creates a "non-critical" virtual link. When +the action list also contains tc-gate (more details below), the virtual link +becomes "time-critical" (draws frame buffers from a reserved memory partition, +etc). + +The 3 routing actions that are supported are "trap", "drop" and "redirect". + +Example 1: send frames received on swp2 with a DA of 42:be:24:9b:76:20 to the +CPU and to swp3. This type of key (DA only) when the port's VLAN awareness +state is off:: + + tc qdisc add dev swp2 clsact + tc filter add dev swp2 ingress flower skip_sw dst_mac 42:be:24:9b:76:20 \ + action mirred egress redirect dev swp3 \ + action trap + +Example 2: drop frames received on swp2 with a DA of 42:be:24:9b:76:20, a VID +of 100 and a PCP of 0:: + + tc filter add dev swp2 ingress protocol 802.1Q flower skip_sw \ + dst_mac 42:be:24:9b:76:20 vlan_id 100 vlan_prio 0 action drop + +Time-based ingress policing +--------------------------- + +The TTEthernet hardware abilities of the switch can be constrained to act +similarly to the Per-Stream Filtering and Policing (PSFP) clause specified in +IEEE 802.1Q-2018 (formerly 802.1Qci). This means it can be used to perform +tight timing-based admission control for up to 1024 flows (identified by a +tuple composed of destination MAC address, VLAN ID and VLAN PCP). Packets which +are received outside their expected reception window are dropped. + +This capability can be managed through the offload of the tc-gate action. As +routing actions are intrinsic to virtual links in TTEthernet (which performs +explicit routing of time-critical traffic and does not leave that in the hands +of the FDB, flooding etc), the tc-gate action may never appear alone when +asking sja1105 to offload it. One (or more) redirect or trap actions must also +follow along. + +Example: create a tc-taprio schedule that is phase-aligned with a tc-gate +schedule (the clocks must be synchronized by a 1588 application stack, which is +outside the scope of this document). No packet delivered by the sender will be +dropped. Note that the reception window is larger than the transmission window +(and much more so, in this example) to compensate for the packet propagation +delay of the link (which can be determined by the 1588 application stack). + +Receiver (sja1105):: + + tc qdisc add dev swp2 clsact + now=$(phc_ctl /dev/ptp1 get | awk '/clock time is/ {print $5}') && \ + sec=$(echo $now | awk -F. '{print $1}') && \ + base_time="$(((sec + 2) * 1000000000))" && \ + echo "base time ${base_time}" + tc filter add dev swp2 ingress flower skip_sw \ + dst_mac 42:be:24:9b:76:20 \ + action gate base-time ${base_time} \ + sched-entry OPEN 60000 -1 -1 \ + sched-entry CLOSE 40000 -1 -1 \ + action trap + +Sender:: + + now=$(phc_ctl /dev/ptp0 get | awk '/clock time is/ {print $5}') && \ + sec=$(echo $now | awk -F. '{print $1}') && \ + base_time="$(((sec + 2) * 1000000000))" && \ + echo "base time ${base_time}" + tc qdisc add dev eno0 parent root taprio \ + num_tc 8 \ + map 0 1 2 3 4 5 6 7 \ + queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 \ + base-time ${base_time} \ + sched-entry S 01 50000 \ + sched-entry S 00 50000 \ + flags 2 + +The engine used to schedule the ingress gate operations is the same that the +one used for the tc-taprio offload. Therefore, the restrictions regarding the +fact that no two gate actions (either tc-gate or tc-taprio gates) may fire at +the same time (during the same 200 ns slot) still apply. + +To come in handy, it is possible to share time-triggered virtual links across +more than 1 ingress port, via flow blocks. In this case, the restriction of +firing at the same time does not apply because there is a single schedule in +the system, that of the shared virtual link:: + + tc qdisc add dev swp2 ingress_block 1 clsact + tc qdisc add dev swp3 ingress_block 1 clsact + tc filter add block 1 flower skip_sw dst_mac 42:be:24:9b:76:20 \ + action gate index 2 \ + base-time 0 \ + sched-entry OPEN 50000000 -1 -1 \ + sched-entry CLOSE 50000000 -1 -1 \ + action trap + +Hardware statistics for each flow are also available ("pkts" counts the number +of dropped frames, which is a sum of frames dropped due to timing violations, +lack of destination ports and MTU enforcement checks). Byte-level counters are +not available. + +Limitations +=========== + +The SJA1105 switch family always performs VLAN processing. When configured as +VLAN-unaware, frames carry a different VLAN tag internally, depending on +whether the port is standalone or under a VLAN-unaware bridge. + +The virtual link keys are always fixed at {MAC DA, VLAN ID, VLAN PCP}, but the +driver asks for the VLAN ID and VLAN PCP when the port is under a VLAN-aware +bridge. Otherwise, it fills in the VLAN ID and PCP automatically, based on +whether the port is standalone or in a VLAN-unaware bridge, and accepts only +"VLAN-unaware" tc-flower keys (MAC DA). + +The existing tc-flower keys that are offloaded using virtual links are no +longer operational after one of the following happens: + +- port was standalone and joins a bridge (VLAN-aware or VLAN-unaware) +- port is part of a bridge whose VLAN awareness state changes +- port was part of a bridge and becomes standalone +- port was standalone, but another port joins a VLAN-aware bridge and this + changes the global VLAN awareness state of the bridge + +The driver cannot veto all these operations, and it cannot update/remove the +existing tc-flower filters either. So for proper operation, the tc-flower +filters should be installed only after the forwarding configuration of the port +has been made, and removed by user space before making any changes to it. + +Device Tree bindings and board design +===================================== + +This section references ``Documentation/devicetree/bindings/net/dsa/nxp,sja1105.yaml`` +and aims to showcase some potential switch caveats. + +RMII PHY role and out-of-band signaling +--------------------------------------- + +In the RMII spec, the 50 MHz clock signals are either driven by the MAC or by +an external oscillator (but not by the PHY). +But the spec is rather loose and devices go outside it in several ways. +Some PHYs go against the spec and may provide an output pin where they source +the 50 MHz clock themselves, in an attempt to be helpful. +On the other hand, the SJA1105 is only binary configurable - when in the RMII +MAC role it will also attempt to drive the clock signal. To prevent this from +happening it must be put in RMII PHY role. +But doing so has some unintended consequences. +In the RMII spec, the PHY can transmit extra out-of-band signals via RXD[1:0]. +These are practically some extra code words (/J/ and /K/) sent prior to the +preamble of each frame. The MAC does not have this out-of-band signaling +mechanism defined by the RMII spec. +So when the SJA1105 port is put in PHY role to avoid having 2 drivers on the +clock signal, inevitably an RMII PHY-to-PHY connection is created. The SJA1105 +emulates a PHY interface fully and generates the /J/ and /K/ symbols prior to +frame preambles, which the real PHY is not expected to understand. So the PHY +simply encodes the extra symbols received from the SJA1105-as-PHY onto the +100Base-Tx wire. +On the other side of the wire, some link partners might discard these extra +symbols, while others might choke on them and discard the entire Ethernet +frames that follow along. This looks like packet loss with some link partners +but not with others. +The take-away is that in RMII mode, the SJA1105 must be let to drive the +reference clock if connected to a PHY. + +RGMII fixed-link and internal delays +------------------------------------ + +As mentioned in the bindings document, the second generation of devices has +tunable delay lines as part of the MAC, which can be used to establish the +correct RGMII timing budget. +When powered up, these can shift the Rx and Tx clocks with a phase difference +between 73.8 and 101.7 degrees. +The catch is that the delay lines need to lock onto a clock signal with a +stable frequency. This means that there must be at least 2 microseconds of +silence between the clock at the old vs at the new frequency. Otherwise the +lock is lost and the delay lines must be reset (powered down and back up). +In RGMII the clock frequency changes with link speed (125 MHz at 1000 Mbps, 25 +MHz at 100 Mbps and 2.5 MHz at 10 Mbps), and link speed might change during the +AN process. +In the situation where the switch port is connected through an RGMII fixed-link +to a link partner whose link state life cycle is outside the control of Linux +(such as a different SoC), then the delay lines would remain unlocked (and +inactive) until there is manual intervention (ifdown/ifup on the switch port). +The take-away is that in RGMII mode, the switch's internal delays are only +reliable if the link partner never changes link speeds, or if it does, it does +so in a way that is coordinated with the switch port (practically, both ends of +the fixed-link are under control of the same Linux system). +As to why would a fixed-link interface ever change link speeds: there are +Ethernet controllers out there which come out of reset in 100 Mbps mode, and +their driver inevitably needs to change the speed and clock frequency if it's +required to work at gigabit. + +MDIO bus and PHY management +--------------------------- + +The SJA1105 does not have an MDIO bus and does not perform in-band AN either. +Therefore there is no link state notification coming from the switch device. +A board would need to hook up the PHYs connected to the switch to any other +MDIO bus available to Linux within the system (e.g. to the DSA master's MDIO +bus). Link state management then works by the driver manually keeping in sync +(over SPI commands) the MAC link speed with the settings negotiated by the PHY. + +By comparison, the SJA1110 supports an MDIO slave access point over which its +internal 100base-T1 PHYs can be accessed from the host. This is, however, not +used by the driver, instead the internal 100base-T1 and 100base-TX PHYs are +accessed through SPI commands, modeled in Linux as virtual MDIO buses. + +The microcontroller attached to the SJA1110 port 0 also has an MDIO controller +operating in master mode, however the driver does not support this either, +since the microcontroller gets disabled when the Linux driver operates. +Discrete PHYs connected to the switch ports should have their MDIO interface +attached to an MDIO controller from the host system and not to the switch, +similar to SJA1105. + +Port compatibility matrix +------------------------- + +The SJA1105 port compatibility matrix is: + +===== ============== ============== ============== +Port SJA1105E/T SJA1105P/Q SJA1105R/S +===== ============== ============== ============== +0 xMII xMII xMII +1 xMII xMII xMII +2 xMII xMII xMII +3 xMII xMII xMII +4 xMII xMII SGMII +===== ============== ============== ============== + + +The SJA1110 port compatibility matrix is: + +===== ============== ============== ============== ============== +Port SJA1110A SJA1110B SJA1110C SJA1110D +===== ============== ============== ============== ============== +0 RevMII (uC) RevMII (uC) RevMII (uC) RevMII (uC) +1 100base-TX 100base-TX 100base-TX + or SGMII SGMII +2 xMII xMII xMII xMII + or SGMII or SGMII +3 xMII xMII xMII + or SGMII or SGMII SGMII + or 2500base-X or 2500base-X or 2500base-X +4 SGMII SGMII SGMII SGMII + or 2500base-X or 2500base-X or 2500base-X or 2500base-X +5 100base-T1 100base-T1 100base-T1 100base-T1 +6 100base-T1 100base-T1 100base-T1 100base-T1 +7 100base-T1 100base-T1 100base-T1 100base-T1 +8 100base-T1 100base-T1 n/a n/a +9 100base-T1 100base-T1 n/a n/a +10 100base-T1 n/a n/a n/a +===== ============== ============== ============== ============== diff --git a/Documentation/networking/eql.rst b/Documentation/networking/eql.rst new file mode 100644 index 0000000000..a628c4c811 --- /dev/null +++ b/Documentation/networking/eql.rst @@ -0,0 +1,373 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================================== +EQL Driver: Serial IP Load Balancing HOWTO +========================================== + + Simon "Guru Aleph-Null" Janes, simon@ncm.com + + v1.1, February 27, 1995 + + This is the manual for the EQL device driver. EQL is a software device + that lets you load-balance IP serial links (SLIP or uncompressed PPP) + to increase your bandwidth. It will not reduce your latency (i.e. ping + times) except in the case where you already have lots of traffic on + your link, in which it will help them out. This driver has been tested + with the 1.1.75 kernel, and is known to have patched cleanly with + 1.1.86. Some testing with 1.1.92 has been done with the v1.1 patch + which was only created to patch cleanly in the very latest kernel + source trees. (Yes, it worked fine.) + +1. Introduction +=============== + + Which is worse? A huge fee for a 56K leased line or two phone lines? + It's probably the former. If you find yourself craving more bandwidth, + and have a ISP that is flexible, it is now possible to bind modems + together to work as one point-to-point link to increase your + bandwidth. All without having to have a special black box on either + side. + + + The eql driver has only been tested with the Livingston PortMaster-2e + terminal server. I do not know if other terminal servers support load- + balancing, but I do know that the PortMaster does it, and does it + almost as well as the eql driver seems to do it (-- Unfortunately, in + my testing so far, the Livingston PortMaster 2e's load-balancing is a + good 1 to 2 KB/s slower than the test machine working with a 28.8 Kbps + and 14.4 Kbps connection. However, I am not sure that it really is + the PortMaster, or if it's Linux's TCP drivers. I'm told that Linux's + TCP implementation is pretty fast though.--) + + + I suggest to ISPs out there that it would probably be fair to charge + a load-balancing client 75% of the cost of the second line and 50% of + the cost of the third line etc... + + + Hey, we can all dream you know... + + +2. Kernel Configuration +======================= + + Here I describe the general steps of getting a kernel up and working + with the eql driver. From patching, building, to installing. + + +2.1. Patching The Kernel +------------------------ + + If you do not have or cannot get a copy of the kernel with the eql + driver folded into it, get your copy of the driver from + ftp://slaughter.ncm.com/pub/Linux/LOAD_BALANCING/eql-1.1.tar.gz. + Unpack this archive someplace obvious like /usr/local/src/. It will + create the following files:: + + -rw-r--r-- guru/ncm 198 Jan 19 18:53 1995 eql-1.1/NO-WARRANTY + -rw-r--r-- guru/ncm 30620 Feb 27 21:40 1995 eql-1.1/eql-1.1.patch + -rwxr-xr-x guru/ncm 16111 Jan 12 22:29 1995 eql-1.1/eql_enslave + -rw-r--r-- guru/ncm 2195 Jan 10 21:48 1995 eql-1.1/eql_enslave.c + + Unpack a recent kernel (something after 1.1.92) someplace convenient + like say /usr/src/linux-1.1.92.eql. Use symbolic links to point + /usr/src/linux to this development directory. + + + Apply the patch by running the commands:: + + cd /usr/src + patch </usr/local/src/eql-1.1/eql-1.1.patch + + +2.2. Building The Kernel +------------------------ + + After patching the kernel, run make config and configure the kernel + for your hardware. + + + After configuration, make and install according to your habit. + + +3. Network Configuration +======================== + + So far, I have only used the eql device with the DSLIP SLIP connection + manager by Matt Dillon (-- "The man who sold his soul to code so much + so quickly."--) . How you configure it for other "connection" + managers is up to you. Most other connection managers that I've seen + don't do a very good job when it comes to handling more than one + connection. + + +3.1. /etc/rc.d/rc.inet1 +----------------------- + + In rc.inet1, ifconfig the eql device to the IP address you usually use + for your machine, and the MTU you prefer for your SLIP lines. One + could argue that MTU should be roughly half the usual size for two + modems, one-third for three, one-fourth for four, etc... But going + too far below 296 is probably overkill. Here is an example ifconfig + command that sets up the eql device:: + + ifconfig eql 198.67.33.239 mtu 1006 + + Once the eql device is up and running, add a static default route to + it in the routing table using the cool new route syntax that makes + life so much easier:: + + route add default eql + + +3.2. Enslaving Devices By Hand +------------------------------ + + Enslaving devices by hand requires two utility programs: eql_enslave + and eql_emancipate (-- eql_emancipate hasn't been written because when + an enslaved device "dies", it is automatically taken out of the queue. + I haven't found a good reason to write it yet... other than for + completeness, but that isn't a good motivator is it?--) + + + The syntax for enslaving a device is "eql_enslave <master-name> + <slave-name> <estimated-bps>". Here are some example enslavings:: + + eql_enslave eql sl0 28800 + eql_enslave eql ppp0 14400 + eql_enslave eql sl1 57600 + + When you want to free a device from its life of slavery, you can + either down the device with ifconfig (eql will automatically bury the + dead slave and remove it from its queue) or use eql_emancipate to free + it. (-- Or just ifconfig it down, and the eql driver will take it out + for you.--):: + + eql_emancipate eql sl0 + eql_emancipate eql ppp0 + eql_emancipate eql sl1 + + +3.3. DSLIP Configuration for the eql Device +------------------------------------------- + + The general idea is to bring up and keep up as many SLIP connections + as you need, automatically. + + +3.3.1. /etc/slip/runslip.conf +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + + Here is an example runslip.conf:: + + name sl-line-1 + enabled + baud 38400 + mtu 576 + ducmd -e /etc/slip/dialout/cua2-288.xp -t 9 + command eql_enslave eql $interface 28800 + address 198.67.33.239 + line /dev/cua2 + + name sl-line-2 + enabled + baud 38400 + mtu 576 + ducmd -e /etc/slip/dialout/cua3-288.xp -t 9 + command eql_enslave eql $interface 28800 + address 198.67.33.239 + line /dev/cua3 + + +3.4. Using PPP and the eql Device +--------------------------------- + + I have not yet done any load-balancing testing for PPP devices, mainly + because I don't have a PPP-connection manager like SLIP has with + DSLIP. I did find a good tip from LinuxNET:Billy for PPP performance: + make sure you have asyncmap set to something so that control + characters are not escaped. + + + I tried to fix up a PPP script/system for redialing lost PPP + connections for use with the eql driver the weekend of Feb 25-26 '95 + (Hereafter known as the 8-hour PPP Hate Festival). Perhaps later this + year. + + +4. About the Slave Scheduler Algorithm +====================================== + + The slave scheduler probably could be replaced with a dozen other + things and push traffic much faster. The formula in the current set + up of the driver was tuned to handle slaves with wildly different + bits-per-second "priorities". + + + All testing I have done was with two 28.8 V.FC modems, one connecting + at 28800 bps or slower, and the other connecting at 14400 bps all the + time. + + + One version of the scheduler was able to push 5.3 K/s through the + 28800 and 14400 connections, but when the priorities on the links were + very wide apart (57600 vs. 14400) the "faster" modem received all + traffic and the "slower" modem starved. + + +5. Testers' Reports +=================== + + Some people have experimented with the eql device with newer + kernels (than 1.1.75). I have since updated the driver to patch + cleanly in newer kernels because of the removal of the old "slave- + balancing" driver config option. + + + - icee from LinuxNET patched 1.1.86 without any rejects and was able + to boot the kernel and enslave a couple of ISDN PPP links. + +5.1. Randolph Bentson's Test Report +----------------------------------- + + :: + + From bentson@grieg.seaslug.org Wed Feb 8 19:08:09 1995 + Date: Tue, 7 Feb 95 22:57 PST + From: Randolph Bentson <bentson@grieg.seaslug.org> + To: guru@ncm.com + Subject: EQL driver tests + + + I have been checking out your eql driver. (Nice work, that!) + Although you may already done this performance testing, here + are some data I've discovered. + + Randolph Bentson + bentson@grieg.seaslug.org + +------------------------------------------------------------------ + + + A pseudo-device driver, EQL, written by Simon Janes, can be used + to bundle multiple SLIP connections into what appears to be a + single connection. This allows one to improve dial-up network + connectivity gradually, without having to buy expensive DSU/CSU + hardware and services. + + I have done some testing of this software, with two goals in + mind: first, to ensure it actually works as described and + second, as a method of exercising my device driver. + + The following performance measurements were derived from a set + of SLIP connections run between two Linux systems (1.1.84) using + a 486DX2/66 with a Cyclom-8Ys and a 486SLC/40 with a Cyclom-16Y. + (Ports 0,1,2,3 were used. A later configuration will distribute + port selection across the different Cirrus chips on the boards.) + Once a link was established, I timed a binary ftp transfer of + 289284 bytes of data. If there were no overhead (packet headers, + inter-character and inter-packet delays, etc.) the transfers + would take the following times:: + + bits/sec seconds + 345600 8.3 + 234600 12.3 + 172800 16.7 + 153600 18.8 + 76800 37.6 + 57600 50.2 + 38400 75.3 + 28800 100.4 + 19200 150.6 + 9600 301.3 + + A single line running at the lower speeds and with large packets + comes to within 2% of this. Performance is limited for the higher + speeds (as predicted by the Cirrus databook) to an aggregate of + about 160 kbits/sec. The next round of testing will distribute + the load across two or more Cirrus chips. + + The good news is that one gets nearly the full advantage of the + second, third, and fourth line's bandwidth. (The bad news is + that the connection establishment seemed fragile for the higher + speeds. Once established, the connection seemed robust enough.) + + ====== ======== === ======== ======= ======= === + #lines speed mtu seconds theory actual %of + kbit/sec duration speed speed max + ====== ======== === ======== ======= ======= === + 3 115200 900 _ 345600 + 3 115200 400 18.1 345600 159825 46 + 2 115200 900 _ 230400 + 2 115200 600 18.1 230400 159825 69 + 2 115200 400 19.3 230400 149888 65 + 4 57600 900 _ 234600 + 4 57600 600 _ 234600 + 4 57600 400 _ 234600 + 3 57600 600 20.9 172800 138413 80 + 3 57600 900 21.2 172800 136455 78 + 3 115200 600 21.7 345600 133311 38 + 3 57600 400 22.5 172800 128571 74 + 4 38400 900 25.2 153600 114795 74 + 4 38400 600 26.4 153600 109577 71 + 4 38400 400 27.3 153600 105965 68 + 2 57600 900 29.1 115200 99410.3 86 + 1 115200 900 30.7 115200 94229.3 81 + 2 57600 600 30.2 115200 95789.4 83 + 3 38400 900 30.3 115200 95473.3 82 + 3 38400 600 31.2 115200 92719.2 80 + 1 115200 600 31.3 115200 92423 80 + 2 57600 400 32.3 115200 89561.6 77 + 1 115200 400 32.8 115200 88196.3 76 + 3 38400 400 33.5 115200 86353.4 74 + 2 38400 900 43.7 76800 66197.7 86 + 2 38400 600 44 76800 65746.4 85 + 2 38400 400 47.2 76800 61289 79 + 4 19200 900 50.8 76800 56945.7 74 + 4 19200 400 53.2 76800 54376.7 70 + 4 19200 600 53.7 76800 53870.4 70 + 1 57600 900 54.6 57600 52982.4 91 + 1 57600 600 56.2 57600 51474 89 + 3 19200 900 60.5 57600 47815.5 83 + 1 57600 400 60.2 57600 48053.8 83 + 3 19200 600 62 57600 46658.7 81 + 3 19200 400 64.7 57600 44711.6 77 + 1 38400 900 79.4 38400 36433.8 94 + 1 38400 600 82.4 38400 35107.3 91 + 2 19200 900 84.4 38400 34275.4 89 + 1 38400 400 86.8 38400 33327.6 86 + 2 19200 600 87.6 38400 33023.3 85 + 2 19200 400 91.2 38400 31719.7 82 + 4 9600 900 94.7 38400 30547.4 79 + 4 9600 400 106 38400 27290.9 71 + 4 9600 600 110 38400 26298.5 68 + 3 9600 900 118 28800 24515.6 85 + 3 9600 600 120 28800 24107 83 + 3 9600 400 131 28800 22082.7 76 + 1 19200 900 155 19200 18663.5 97 + 1 19200 600 161 19200 17968 93 + 1 19200 400 170 19200 17016.7 88 + 2 9600 600 176 19200 16436.6 85 + 2 9600 900 180 19200 16071.3 83 + 2 9600 400 181 19200 15982.5 83 + 1 9600 900 305 9600 9484.72 98 + 1 9600 600 314 9600 9212.87 95 + 1 9600 400 332 9600 8713.37 90 + ====== ======== === ======== ======= ======= === + +5.2. Anthony Healy's Report +--------------------------- + + :: + + Date: Mon, 13 Feb 1995 16:17:29 +1100 (EST) + From: Antony Healey <ahealey@st.nepean.uws.edu.au> + To: Simon Janes <guru@ncm.com> + Subject: Re: Load Balancing + + Hi Simon, + I've installed your patch and it works great. I have trialed + it over twin SL/IP lines, just over null modems, but I was + able to data at over 48Kb/s [ISDN link -Simon]. I managed a + transfer of up to 7.5 Kbyte/s on one go, but averaged around + 6.4 Kbyte/s, which I think is pretty cool. :) diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst new file mode 100644 index 0000000000..2540c70952 --- /dev/null +++ b/Documentation/networking/ethtool-netlink.rst @@ -0,0 +1,2103 @@ +============================= +Netlink interface for ethtool +============================= + + +Basic information +================= + +Netlink interface for ethtool uses generic netlink family ``ethtool`` +(userspace application should use macros ``ETHTOOL_GENL_NAME`` and +``ETHTOOL_GENL_VERSION`` defined in ``<linux/ethtool_netlink.h>`` uapi +header). This family does not use a specific header, all information in +requests and replies is passed using netlink attributes. + +The ethtool netlink interface uses extended ACK for error and warning +reporting, userspace application developers are encouraged to make these +messages available to user in a suitable way. + +Requests can be divided into three categories: "get" (retrieving information), +"set" (setting parameters) and "action" (invoking an action). + +All "set" and "action" type requests require admin privileges +(``CAP_NET_ADMIN`` in the namespace). Most "get" type requests are allowed for +anyone but there are exceptions (where the response contains sensitive +information). In some cases, the request as such is allowed for anyone but +unprivileged users have attributes with sensitive information (e.g. +wake-on-lan password) omitted. + + +Conventions +=========== + +Attributes which represent a boolean value usually use NLA_U8 type so that we +can distinguish three states: "on", "off" and "not present" (meaning the +information is not available in "get" requests or value is not to be changed +in "set" requests). For these attributes, the "true" value should be passed as +number 1 but any non-zero value should be understood as "true" by recipient. +In the tables below, "bool" denotes NLA_U8 attributes interpreted in this way. + +In the message structure descriptions below, if an attribute name is suffixed +with "+", parent nest can contain multiple attributes of the same type. This +implements an array of entries. + +Attributes that need to be filled-in by device drivers and that are dumped to +user space based on whether they are valid or not should not use zero as a +valid value. This avoids the need to explicitly signal the validity of the +attribute in the device driver API. + + +Request header +============== + +Each request or reply message contains a nested attribute with common header. +Structure of this header is + + ============================== ====== ============================= + ``ETHTOOL_A_HEADER_DEV_INDEX`` u32 device ifindex + ``ETHTOOL_A_HEADER_DEV_NAME`` string device name + ``ETHTOOL_A_HEADER_FLAGS`` u32 flags common for all requests + ============================== ====== ============================= + +``ETHTOOL_A_HEADER_DEV_INDEX`` and ``ETHTOOL_A_HEADER_DEV_NAME`` identify the +device message relates to. One of them is sufficient in requests, if both are +used, they must identify the same device. Some requests, e.g. global string +sets, do not require device identification. Most ``GET`` requests also allow +dump requests without device identification to query the same information for +all devices providing it (each device in a separate message). + +``ETHTOOL_A_HEADER_FLAGS`` is a bitmap of request flags common for all request +types. The interpretation of these flags is the same for all request types but +the flags may not apply to requests. Recognized flags are: + + ================================= =================================== + ``ETHTOOL_FLAG_COMPACT_BITSETS`` use compact format bitsets in reply + ``ETHTOOL_FLAG_OMIT_REPLY`` omit optional reply (_SET and _ACT) + ``ETHTOOL_FLAG_STATS`` include optional device statistics + ================================= =================================== + +New request flags should follow the general idea that if the flag is not set, +the behaviour is backward compatible, i.e. requests from old clients not aware +of the flag should be interpreted the way the client expects. A client must +not set flags it does not understand. + + +Bit sets +======== + +For short bitmaps of (reasonably) fixed length, standard ``NLA_BITFIELD32`` +type is used. For arbitrary length bitmaps, ethtool netlink uses a nested +attribute with contents of one of two forms: compact (two binary bitmaps +representing bit values and mask of affected bits) and bit-by-bit (list of +bits identified by either index or name). + +Verbose (bit-by-bit) bitsets allow sending symbolic names for bits together +with their values which saves a round trip (when the bitset is passed in a +request) or at least a second request (when the bitset is in a reply). This is +useful for one shot applications like traditional ethtool command. On the +other hand, long running applications like ethtool monitor (displaying +notifications) or network management daemons may prefer fetching the names +only once and using compact form to save message size. Notifications from +ethtool netlink interface always use compact form for bitsets. + +A bitset can represent either a value/mask pair (``ETHTOOL_A_BITSET_NOMASK`` +not set) or a single bitmap (``ETHTOOL_A_BITSET_NOMASK`` set). In requests +modifying a bitmap, the former changes the bit set in mask to values set in +value and preserves the rest; the latter sets the bits set in the bitmap and +clears the rest. + +Compact form: nested (bitset) attribute contents: + + ============================ ====== ============================ + ``ETHTOOL_A_BITSET_NOMASK`` flag no mask, only a list + ``ETHTOOL_A_BITSET_SIZE`` u32 number of significant bits + ``ETHTOOL_A_BITSET_VALUE`` binary bitmap of bit values + ``ETHTOOL_A_BITSET_MASK`` binary bitmap of valid bits + ============================ ====== ============================ + +Value and mask must have length at least ``ETHTOOL_A_BITSET_SIZE`` bits +rounded up to a multiple of 32 bits. They consist of 32-bit words in host byte +order, words ordered from least significant to most significant (i.e. the same +way as bitmaps are passed with ioctl interface). + +For compact form, ``ETHTOOL_A_BITSET_SIZE`` and ``ETHTOOL_A_BITSET_VALUE`` are +mandatory. ``ETHTOOL_A_BITSET_MASK`` attribute is mandatory if +``ETHTOOL_A_BITSET_NOMASK`` is not set (bitset represents a value/mask pair); +if ``ETHTOOL_A_BITSET_NOMASK`` is not set, ``ETHTOOL_A_BITSET_MASK`` is not +allowed (bitset represents a single bitmap. + +Kernel bit set length may differ from userspace length if older application is +used on newer kernel or vice versa. If userspace bitmap is longer, an error is +issued only if the request actually tries to set values of some bits not +recognized by kernel. + +Bit-by-bit form: nested (bitset) attribute contents: + + +------------------------------------+--------+-----------------------------+ + | ``ETHTOOL_A_BITSET_NOMASK`` | flag | no mask, only a list | + +------------------------------------+--------+-----------------------------+ + | ``ETHTOOL_A_BITSET_SIZE`` | u32 | number of significant bits | + +------------------------------------+--------+-----------------------------+ + | ``ETHTOOL_A_BITSET_BITS`` | nested | array of bits | + +-+----------------------------------+--------+-----------------------------+ + | | ``ETHTOOL_A_BITSET_BITS_BIT+`` | nested | one bit | + +-+-+--------------------------------+--------+-----------------------------+ + | | | ``ETHTOOL_A_BITSET_BIT_INDEX`` | u32 | bit index (0 for LSB) | + +-+-+--------------------------------+--------+-----------------------------+ + | | | ``ETHTOOL_A_BITSET_BIT_NAME`` | string | bit name | + +-+-+--------------------------------+--------+-----------------------------+ + | | | ``ETHTOOL_A_BITSET_BIT_VALUE`` | flag | present if bit is set | + +-+-+--------------------------------+--------+-----------------------------+ + +Bit size is optional for bit-by-bit form. ``ETHTOOL_A_BITSET_BITS`` nest can +only contain ``ETHTOOL_A_BITSET_BITS_BIT`` attributes but there can be an +arbitrary number of them. A bit may be identified by its index or by its +name. When used in requests, listed bits are set to 0 or 1 according to +``ETHTOOL_A_BITSET_BIT_VALUE``, the rest is preserved. A request fails if +index exceeds kernel bit length or if name is not recognized. + +When ``ETHTOOL_A_BITSET_NOMASK`` flag is present, bitset is interpreted as +a simple bitmap. ``ETHTOOL_A_BITSET_BIT_VALUE`` attributes are not used in +such case. Such bitset represents a bitmap with listed bits set and the rest +zero. + +In requests, application can use either form. Form used by kernel in reply is +determined by ``ETHTOOL_FLAG_COMPACT_BITSETS`` flag in flags field of request +header. Semantics of value and mask depends on the attribute. + + +List of message types +===================== + +All constants identifying message types use ``ETHTOOL_CMD_`` prefix and suffix +according to message purpose: + + ============== ====================================== + ``_GET`` userspace request to retrieve data + ``_SET`` userspace request to set data + ``_ACT`` userspace request to perform an action + ``_GET_REPLY`` kernel reply to a ``GET`` request + ``_SET_REPLY`` kernel reply to a ``SET`` request + ``_ACT_REPLY`` kernel reply to an ``ACT`` request + ``_NTF`` kernel notification + ============== ====================================== + +Userspace to kernel: + + ===================================== ================================= + ``ETHTOOL_MSG_STRSET_GET`` get string set + ``ETHTOOL_MSG_LINKINFO_GET`` get link settings + ``ETHTOOL_MSG_LINKINFO_SET`` set link settings + ``ETHTOOL_MSG_LINKMODES_GET`` get link modes info + ``ETHTOOL_MSG_LINKMODES_SET`` set link modes info + ``ETHTOOL_MSG_LINKSTATE_GET`` get link state + ``ETHTOOL_MSG_DEBUG_GET`` get debugging settings + ``ETHTOOL_MSG_DEBUG_SET`` set debugging settings + ``ETHTOOL_MSG_WOL_GET`` get wake-on-lan settings + ``ETHTOOL_MSG_WOL_SET`` set wake-on-lan settings + ``ETHTOOL_MSG_FEATURES_GET`` get device features + ``ETHTOOL_MSG_FEATURES_SET`` set device features + ``ETHTOOL_MSG_PRIVFLAGS_GET`` get private flags + ``ETHTOOL_MSG_PRIVFLAGS_SET`` set private flags + ``ETHTOOL_MSG_RINGS_GET`` get ring sizes + ``ETHTOOL_MSG_RINGS_SET`` set ring sizes + ``ETHTOOL_MSG_CHANNELS_GET`` get channel counts + ``ETHTOOL_MSG_CHANNELS_SET`` set channel counts + ``ETHTOOL_MSG_COALESCE_GET`` get coalescing parameters + ``ETHTOOL_MSG_COALESCE_SET`` set coalescing parameters + ``ETHTOOL_MSG_PAUSE_GET`` get pause parameters + ``ETHTOOL_MSG_PAUSE_SET`` set pause parameters + ``ETHTOOL_MSG_EEE_GET`` get EEE settings + ``ETHTOOL_MSG_EEE_SET`` set EEE settings + ``ETHTOOL_MSG_TSINFO_GET`` get timestamping info + ``ETHTOOL_MSG_CABLE_TEST_ACT`` action start cable test + ``ETHTOOL_MSG_CABLE_TEST_TDR_ACT`` action start raw TDR cable test + ``ETHTOOL_MSG_TUNNEL_INFO_GET`` get tunnel offload info + ``ETHTOOL_MSG_FEC_GET`` get FEC settings + ``ETHTOOL_MSG_FEC_SET`` set FEC settings + ``ETHTOOL_MSG_MODULE_EEPROM_GET`` read SFP module EEPROM + ``ETHTOOL_MSG_STATS_GET`` get standard statistics + ``ETHTOOL_MSG_PHC_VCLOCKS_GET`` get PHC virtual clocks info + ``ETHTOOL_MSG_MODULE_SET`` set transceiver module parameters + ``ETHTOOL_MSG_MODULE_GET`` get transceiver module parameters + ``ETHTOOL_MSG_PSE_SET`` set PSE parameters + ``ETHTOOL_MSG_PSE_GET`` get PSE parameters + ``ETHTOOL_MSG_RSS_GET`` get RSS settings + ``ETHTOOL_MSG_MM_GET`` get MAC merge layer state + ``ETHTOOL_MSG_MM_SET`` set MAC merge layer parameters + ===================================== ================================= + +Kernel to userspace: + + ======================================== ================================= + ``ETHTOOL_MSG_STRSET_GET_REPLY`` string set contents + ``ETHTOOL_MSG_LINKINFO_GET_REPLY`` link settings + ``ETHTOOL_MSG_LINKINFO_NTF`` link settings notification + ``ETHTOOL_MSG_LINKMODES_GET_REPLY`` link modes info + ``ETHTOOL_MSG_LINKMODES_NTF`` link modes notification + ``ETHTOOL_MSG_LINKSTATE_GET_REPLY`` link state info + ``ETHTOOL_MSG_DEBUG_GET_REPLY`` debugging settings + ``ETHTOOL_MSG_DEBUG_NTF`` debugging settings notification + ``ETHTOOL_MSG_WOL_GET_REPLY`` wake-on-lan settings + ``ETHTOOL_MSG_WOL_NTF`` wake-on-lan settings notification + ``ETHTOOL_MSG_FEATURES_GET_REPLY`` device features + ``ETHTOOL_MSG_FEATURES_SET_REPLY`` optional reply to FEATURES_SET + ``ETHTOOL_MSG_FEATURES_NTF`` netdev features notification + ``ETHTOOL_MSG_PRIVFLAGS_GET_REPLY`` private flags + ``ETHTOOL_MSG_PRIVFLAGS_NTF`` private flags + ``ETHTOOL_MSG_RINGS_GET_REPLY`` ring sizes + ``ETHTOOL_MSG_RINGS_NTF`` ring sizes + ``ETHTOOL_MSG_CHANNELS_GET_REPLY`` channel counts + ``ETHTOOL_MSG_CHANNELS_NTF`` channel counts + ``ETHTOOL_MSG_COALESCE_GET_REPLY`` coalescing parameters + ``ETHTOOL_MSG_COALESCE_NTF`` coalescing parameters + ``ETHTOOL_MSG_PAUSE_GET_REPLY`` pause parameters + ``ETHTOOL_MSG_PAUSE_NTF`` pause parameters + ``ETHTOOL_MSG_EEE_GET_REPLY`` EEE settings + ``ETHTOOL_MSG_EEE_NTF`` EEE settings + ``ETHTOOL_MSG_TSINFO_GET_REPLY`` timestamping info + ``ETHTOOL_MSG_CABLE_TEST_NTF`` Cable test results + ``ETHTOOL_MSG_CABLE_TEST_TDR_NTF`` Cable test TDR results + ``ETHTOOL_MSG_TUNNEL_INFO_GET_REPLY`` tunnel offload info + ``ETHTOOL_MSG_FEC_GET_REPLY`` FEC settings + ``ETHTOOL_MSG_FEC_NTF`` FEC settings + ``ETHTOOL_MSG_MODULE_EEPROM_GET_REPLY`` read SFP module EEPROM + ``ETHTOOL_MSG_STATS_GET_REPLY`` standard statistics + ``ETHTOOL_MSG_PHC_VCLOCKS_GET_REPLY`` PHC virtual clocks info + ``ETHTOOL_MSG_MODULE_GET_REPLY`` transceiver module parameters + ``ETHTOOL_MSG_PSE_GET_REPLY`` PSE parameters + ``ETHTOOL_MSG_RSS_GET_REPLY`` RSS settings + ``ETHTOOL_MSG_MM_GET_REPLY`` MAC merge layer status + ======================================== ================================= + +``GET`` requests are sent by userspace applications to retrieve device +information. They usually do not contain any message specific attributes. +Kernel replies with corresponding "GET_REPLY" message. For most types, ``GET`` +request with ``NLM_F_DUMP`` and no device identification can be used to query +the information for all devices supporting the request. + +If the data can be also modified, corresponding ``SET`` message with the same +layout as corresponding ``GET_REPLY`` is used to request changes. Only +attributes where a change is requested are included in such request (also, not +all attributes may be changed). Replies to most ``SET`` request consist only +of error code and extack; if kernel provides additional data, it is sent in +the form of corresponding ``SET_REPLY`` message which can be suppressed by +setting ``ETHTOOL_FLAG_OMIT_REPLY`` flag in request header. + +Data modification also triggers sending a ``NTF`` message with a notification. +These usually bear only a subset of attributes which was affected by the +change. The same notification is issued if the data is modified using other +means (mostly ioctl ethtool interface). Unlike notifications from ethtool +netlink code which are only sent if something actually changed, notifications +triggered by ioctl interface may be sent even if the request did not actually +change any data. + +``ACT`` messages request kernel (driver) to perform a specific action. If some +information is reported by kernel (which can be suppressed by setting +``ETHTOOL_FLAG_OMIT_REPLY`` flag in request header), the reply takes form of +an ``ACT_REPLY`` message. Performing an action also triggers a notification +(``NTF`` message). + +Later sections describe the format and semantics of these messages. + + +STRSET_GET +========== + +Requests contents of a string set as provided by ioctl commands +``ETHTOOL_GSSET_INFO`` and ``ETHTOOL_GSTRINGS.`` String sets are not user +writeable so that the corresponding ``STRSET_SET`` message is only used in +kernel replies. There are two types of string sets: global (independent of +a device, e.g. device feature names) and device specific (e.g. device private +flags). + +Request contents: + + +---------------------------------------+--------+------------------------+ + | ``ETHTOOL_A_STRSET_HEADER`` | nested | request header | + +---------------------------------------+--------+------------------------+ + | ``ETHTOOL_A_STRSET_STRINGSETS`` | nested | string set to request | + +-+-------------------------------------+--------+------------------------+ + | | ``ETHTOOL_A_STRINGSETS_STRINGSET+`` | nested | one string set | + +-+-+-----------------------------------+--------+------------------------+ + | | | ``ETHTOOL_A_STRINGSET_ID`` | u32 | set id | + +-+-+-----------------------------------+--------+------------------------+ + +Kernel response contents: + + +---------------------------------------+--------+-----------------------+ + | ``ETHTOOL_A_STRSET_HEADER`` | nested | reply header | + +---------------------------------------+--------+-----------------------+ + | ``ETHTOOL_A_STRSET_STRINGSETS`` | nested | array of string sets | + +-+-------------------------------------+--------+-----------------------+ + | | ``ETHTOOL_A_STRINGSETS_STRINGSET+`` | nested | one string set | + +-+-+-----------------------------------+--------+-----------------------+ + | | | ``ETHTOOL_A_STRINGSET_ID`` | u32 | set id | + +-+-+-----------------------------------+--------+-----------------------+ + | | | ``ETHTOOL_A_STRINGSET_COUNT`` | u32 | number of strings | + +-+-+-----------------------------------+--------+-----------------------+ + | | | ``ETHTOOL_A_STRINGSET_STRINGS`` | nested | array of strings | + +-+-+-+---------------------------------+--------+-----------------------+ + | | | | ``ETHTOOL_A_STRINGS_STRING+`` | nested | one string | + +-+-+-+-+-------------------------------+--------+-----------------------+ + | | | | | ``ETHTOOL_A_STRING_INDEX`` | u32 | string index | + +-+-+-+-+-------------------------------+--------+-----------------------+ + | | | | | ``ETHTOOL_A_STRING_VALUE`` | string | string value | + +-+-+-+-+-------------------------------+--------+-----------------------+ + | ``ETHTOOL_A_STRSET_COUNTS_ONLY`` | flag | return only counts | + +---------------------------------------+--------+-----------------------+ + +Device identification in request header is optional. Depending on its presence +a and ``NLM_F_DUMP`` flag, there are three type of ``STRSET_GET`` requests: + + - no ``NLM_F_DUMP,`` no device: get "global" stringsets + - no ``NLM_F_DUMP``, with device: get string sets related to the device + - ``NLM_F_DUMP``, no device: get device related string sets for all devices + +If there is no ``ETHTOOL_A_STRSET_STRINGSETS`` array, all string sets of +requested type are returned, otherwise only those specified in the request. +Flag ``ETHTOOL_A_STRSET_COUNTS_ONLY`` tells kernel to only return string +counts of the sets, not the actual strings. + + +LINKINFO_GET +============ + +Requests link settings as provided by ``ETHTOOL_GLINKSETTINGS`` except for +link modes and autonegotiation related information. The request does not use +any attributes. + +Request contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_LINKINFO_HEADER`` nested request header + ==================================== ====== ========================== + +Kernel response contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_LINKINFO_HEADER`` nested reply header + ``ETHTOOL_A_LINKINFO_PORT`` u8 physical port + ``ETHTOOL_A_LINKINFO_PHYADDR`` u8 phy MDIO address + ``ETHTOOL_A_LINKINFO_TP_MDIX`` u8 MDI(-X) status + ``ETHTOOL_A_LINKINFO_TP_MDIX_CTRL`` u8 MDI(-X) control + ``ETHTOOL_A_LINKINFO_TRANSCEIVER`` u8 transceiver + ==================================== ====== ========================== + +Attributes and their values have the same meaning as matching members of the +corresponding ioctl structures. + +``LINKINFO_GET`` allows dump requests (kernel returns reply message for all +devices supporting the request). + + +LINKINFO_SET +============ + +``LINKINFO_SET`` request allows setting some of the attributes reported by +``LINKINFO_GET``. + +Request contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_LINKINFO_HEADER`` nested request header + ``ETHTOOL_A_LINKINFO_PORT`` u8 physical port + ``ETHTOOL_A_LINKINFO_PHYADDR`` u8 phy MDIO address + ``ETHTOOL_A_LINKINFO_TP_MDIX_CTRL`` u8 MDI(-X) control + ==================================== ====== ========================== + +MDI(-X) status and transceiver cannot be set, request with the corresponding +attributes is rejected. + + +LINKMODES_GET +============= + +Requests link modes (supported, advertised and peer advertised) and related +information (autonegotiation status, link speed and duplex) as provided by +``ETHTOOL_GLINKSETTINGS``. The request does not use any attributes. + +Request contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_LINKMODES_HEADER`` nested request header + ==================================== ====== ========================== + +Kernel response contents: + + ========================================== ====== ========================== + ``ETHTOOL_A_LINKMODES_HEADER`` nested reply header + ``ETHTOOL_A_LINKMODES_AUTONEG`` u8 autonegotiation status + ``ETHTOOL_A_LINKMODES_OURS`` bitset advertised link modes + ``ETHTOOL_A_LINKMODES_PEER`` bitset partner link modes + ``ETHTOOL_A_LINKMODES_SPEED`` u32 link speed (Mb/s) + ``ETHTOOL_A_LINKMODES_DUPLEX`` u8 duplex mode + ``ETHTOOL_A_LINKMODES_MASTER_SLAVE_CFG`` u8 Master/slave port mode + ``ETHTOOL_A_LINKMODES_MASTER_SLAVE_STATE`` u8 Master/slave port state + ``ETHTOOL_A_LINKMODES_RATE_MATCHING`` u8 PHY rate matching + ========================================== ====== ========================== + +For ``ETHTOOL_A_LINKMODES_OURS``, value represents advertised modes and mask +represents supported modes. ``ETHTOOL_A_LINKMODES_PEER`` in the reply is a bit +list. + +``LINKMODES_GET`` allows dump requests (kernel returns reply messages for all +devices supporting the request). + + +LINKMODES_SET +============= + +Request contents: + + ========================================== ====== ========================== + ``ETHTOOL_A_LINKMODES_HEADER`` nested request header + ``ETHTOOL_A_LINKMODES_AUTONEG`` u8 autonegotiation status + ``ETHTOOL_A_LINKMODES_OURS`` bitset advertised link modes + ``ETHTOOL_A_LINKMODES_PEER`` bitset partner link modes + ``ETHTOOL_A_LINKMODES_SPEED`` u32 link speed (Mb/s) + ``ETHTOOL_A_LINKMODES_DUPLEX`` u8 duplex mode + ``ETHTOOL_A_LINKMODES_MASTER_SLAVE_CFG`` u8 Master/slave port mode + ``ETHTOOL_A_LINKMODES_RATE_MATCHING`` u8 PHY rate matching + ``ETHTOOL_A_LINKMODES_LANES`` u32 lanes + ========================================== ====== ========================== + +``ETHTOOL_A_LINKMODES_OURS`` bit set allows setting advertised link modes. If +autonegotiation is on (either set now or kept from before), advertised modes +are not changed (no ``ETHTOOL_A_LINKMODES_OURS`` attribute) and at least one +of speed, duplex and lanes is specified, kernel adjusts advertised modes to all +supported modes matching speed, duplex, lanes or all (whatever is specified). +This autoselection is done on ethtool side with ioctl interface, netlink +interface is supposed to allow requesting changes without knowing what exactly +kernel supports. + + +LINKSTATE_GET +============= + +Requests link state information. Link up/down flag (as provided by +``ETHTOOL_GLINK`` ioctl command) is provided. Optionally, extended state might +be provided as well. In general, extended state describes reasons for why a port +is down, or why it operates in some non-obvious mode. This request does not have +any attributes. + +Request contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_LINKSTATE_HEADER`` nested request header + ==================================== ====== ========================== + +Kernel response contents: + + ==================================== ====== ============================ + ``ETHTOOL_A_LINKSTATE_HEADER`` nested reply header + ``ETHTOOL_A_LINKSTATE_LINK`` bool link state (up/down) + ``ETHTOOL_A_LINKSTATE_SQI`` u32 Current Signal Quality Index + ``ETHTOOL_A_LINKSTATE_SQI_MAX`` u32 Max support SQI value + ``ETHTOOL_A_LINKSTATE_EXT_STATE`` u8 link extended state + ``ETHTOOL_A_LINKSTATE_EXT_SUBSTATE`` u8 link extended substate + ``ETHTOOL_A_LINKSTATE_EXT_DOWN_CNT`` u32 count of link down events + ==================================== ====== ============================ + +For most NIC drivers, the value of ``ETHTOOL_A_LINKSTATE_LINK`` returns +carrier flag provided by ``netif_carrier_ok()`` but there are drivers which +define their own handler. + +``ETHTOOL_A_LINKSTATE_EXT_STATE`` and ``ETHTOOL_A_LINKSTATE_EXT_SUBSTATE`` are +optional values. ethtool core can provide either both +``ETHTOOL_A_LINKSTATE_EXT_STATE`` and ``ETHTOOL_A_LINKSTATE_EXT_SUBSTATE``, +or only ``ETHTOOL_A_LINKSTATE_EXT_STATE``, or none of them. + +``LINKSTATE_GET`` allows dump requests (kernel returns reply messages for all +devices supporting the request). + + +Link extended states: + + ================================================ ============================================ + ``ETHTOOL_LINK_EXT_STATE_AUTONEG`` States relating to the autonegotiation or + issues therein + + ``ETHTOOL_LINK_EXT_STATE_LINK_TRAINING_FAILURE`` Failure during link training + + ``ETHTOOL_LINK_EXT_STATE_LINK_LOGICAL_MISMATCH`` Logical mismatch in physical coding sublayer + or forward error correction sublayer + + ``ETHTOOL_LINK_EXT_STATE_BAD_SIGNAL_INTEGRITY`` Signal integrity issues + + ``ETHTOOL_LINK_EXT_STATE_NO_CABLE`` No cable connected + + ``ETHTOOL_LINK_EXT_STATE_CABLE_ISSUE`` Failure is related to cable, + e.g., unsupported cable + + ``ETHTOOL_LINK_EXT_STATE_EEPROM_ISSUE`` Failure is related to EEPROM, e.g., failure + during reading or parsing the data + + ``ETHTOOL_LINK_EXT_STATE_CALIBRATION_FAILURE`` Failure during calibration algorithm + + ``ETHTOOL_LINK_EXT_STATE_POWER_BUDGET_EXCEEDED`` The hardware is not able to provide the + power required from cable or module + + ``ETHTOOL_LINK_EXT_STATE_OVERHEAT`` The module is overheated + + ``ETHTOOL_LINK_EXT_STATE_MODULE`` Transceiver module issue + ================================================ ============================================ + +Link extended substates: + + Autoneg substates: + + =============================================================== ================================ + ``ETHTOOL_LINK_EXT_SUBSTATE_AN_NO_PARTNER_DETECTED`` Peer side is down + + ``ETHTOOL_LINK_EXT_SUBSTATE_AN_ACK_NOT_RECEIVED`` Ack not received from peer side + + ``ETHTOOL_LINK_EXT_SUBSTATE_AN_NEXT_PAGE_EXCHANGE_FAILED`` Next page exchange failed + + ``ETHTOOL_LINK_EXT_SUBSTATE_AN_NO_PARTNER_DETECTED_FORCE_MODE`` Peer side is down during force + mode or there is no agreement of + speed + + ``ETHTOOL_LINK_EXT_SUBSTATE_AN_FEC_MISMATCH_DURING_OVERRIDE`` Forward error correction modes + in both sides are mismatched + + ``ETHTOOL_LINK_EXT_SUBSTATE_AN_NO_HCD`` No Highest Common Denominator + =============================================================== ================================ + + Link training substates: + + =========================================================================== ==================== + ``ETHTOOL_LINK_EXT_SUBSTATE_LT_KR_FRAME_LOCK_NOT_ACQUIRED`` Frames were not + recognized, the + lock failed + + ``ETHTOOL_LINK_EXT_SUBSTATE_LT_KR_LINK_INHIBIT_TIMEOUT`` The lock did not + occur before + timeout + + ``ETHTOOL_LINK_EXT_SUBSTATE_LT_KR_LINK_PARTNER_DID_NOT_SET_RECEIVER_READY`` Peer side did not + send ready signal + after training + process + + ``ETHTOOL_LINK_EXT_SUBSTATE_LT_REMOTE_FAULT`` Remote side is not + ready yet + =========================================================================== ==================== + + Link logical mismatch substates: + + ================================================================ =============================== + ``ETHTOOL_LINK_EXT_SUBSTATE_LLM_PCS_DID_NOT_ACQUIRE_BLOCK_LOCK`` Physical coding sublayer was + not locked in first phase - + block lock + + ``ETHTOOL_LINK_EXT_SUBSTATE_LLM_PCS_DID_NOT_ACQUIRE_AM_LOCK`` Physical coding sublayer was + not locked in second phase - + alignment markers lock + + ``ETHTOOL_LINK_EXT_SUBSTATE_LLM_PCS_DID_NOT_GET_ALIGN_STATUS`` Physical coding sublayer did + not get align status + + ``ETHTOOL_LINK_EXT_SUBSTATE_LLM_FC_FEC_IS_NOT_LOCKED`` FC forward error correction is + not locked + + ``ETHTOOL_LINK_EXT_SUBSTATE_LLM_RS_FEC_IS_NOT_LOCKED`` RS forward error correction is + not locked + ================================================================ =============================== + + Bad signal integrity substates: + + ================================================================= ============================= + ``ETHTOOL_LINK_EXT_SUBSTATE_BSI_LARGE_NUMBER_OF_PHYSICAL_ERRORS`` Large number of physical + errors + + ``ETHTOOL_LINK_EXT_SUBSTATE_BSI_UNSUPPORTED_RATE`` The system attempted to + operate the cable at a rate + that is not formally + supported, which led to + signal integrity issues + + ``ETHTOOL_LINK_EXT_SUBSTATE_BSI_SERDES_REFERENCE_CLOCK_LOST`` The external clock signal for + SerDes is too weak or + unavailable. + + ``ETHTOOL_LINK_EXT_SUBSTATE_BSI_SERDES_ALOS`` The received signal for + SerDes is too weak because + analog loss of signal. + ================================================================= ============================= + + Cable issue substates: + + =================================================== ============================================ + ``ETHTOOL_LINK_EXT_SUBSTATE_CI_UNSUPPORTED_CABLE`` Unsupported cable + + ``ETHTOOL_LINK_EXT_SUBSTATE_CI_CABLE_TEST_FAILURE`` Cable test failure + =================================================== ============================================ + + Transceiver module issue substates: + + =================================================== ============================================ + ``ETHTOOL_LINK_EXT_SUBSTATE_MODULE_CMIS_NOT_READY`` The CMIS Module State Machine did not reach + the ModuleReady state. For example, if the + module is stuck at ModuleFault state + =================================================== ============================================ + +DEBUG_GET +========= + +Requests debugging settings of a device. At the moment, only message mask is +provided. + +Request contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_DEBUG_HEADER`` nested request header + ==================================== ====== ========================== + +Kernel response contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_DEBUG_HEADER`` nested reply header + ``ETHTOOL_A_DEBUG_MSGMASK`` bitset message mask + ==================================== ====== ========================== + +The message mask (``ETHTOOL_A_DEBUG_MSGMASK``) is equal to message level as +provided by ``ETHTOOL_GMSGLVL`` and set by ``ETHTOOL_SMSGLVL`` in ioctl +interface. While it is called message level there for historical reasons, most +drivers and almost all newer drivers use it as a mask of enabled message +classes (represented by ``NETIF_MSG_*`` constants); therefore netlink +interface follows its actual use in practice. + +``DEBUG_GET`` allows dump requests (kernel returns reply messages for all +devices supporting the request). + + +DEBUG_SET +========= + +Set or update debugging settings of a device. At the moment, only message mask +is supported. + +Request contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_DEBUG_HEADER`` nested request header + ``ETHTOOL_A_DEBUG_MSGMASK`` bitset message mask + ==================================== ====== ========================== + +``ETHTOOL_A_DEBUG_MSGMASK`` bit set allows setting or modifying mask of +enabled debugging message types for the device. + + +WOL_GET +======= + +Query device wake-on-lan settings. Unlike most "GET" type requests, +``ETHTOOL_MSG_WOL_GET`` requires (netns) ``CAP_NET_ADMIN`` privileges as it +(potentially) provides SecureOn(tm) password which is confidential. + +Request contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_WOL_HEADER`` nested request header + ==================================== ====== ========================== + +Kernel response contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_WOL_HEADER`` nested reply header + ``ETHTOOL_A_WOL_MODES`` bitset mask of enabled WoL modes + ``ETHTOOL_A_WOL_SOPASS`` binary SecureOn(tm) password + ==================================== ====== ========================== + +In reply, ``ETHTOOL_A_WOL_MODES`` mask consists of modes supported by the +device, value of modes which are enabled. ``ETHTOOL_A_WOL_SOPASS`` is only +included in reply if ``WAKE_MAGICSECURE`` mode is supported. + + +WOL_SET +======= + +Set or update wake-on-lan settings. + +Request contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_WOL_HEADER`` nested request header + ``ETHTOOL_A_WOL_MODES`` bitset enabled WoL modes + ``ETHTOOL_A_WOL_SOPASS`` binary SecureOn(tm) password + ==================================== ====== ========================== + +``ETHTOOL_A_WOL_SOPASS`` is only allowed for devices supporting +``WAKE_MAGICSECURE`` mode. + + +FEATURES_GET +============ + +Gets netdev features like ``ETHTOOL_GFEATURES`` ioctl request. + +Request contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_FEATURES_HEADER`` nested request header + ==================================== ====== ========================== + +Kernel response contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_FEATURES_HEADER`` nested reply header + ``ETHTOOL_A_FEATURES_HW`` bitset dev->hw_features + ``ETHTOOL_A_FEATURES_WANTED`` bitset dev->wanted_features + ``ETHTOOL_A_FEATURES_ACTIVE`` bitset dev->features + ``ETHTOOL_A_FEATURES_NOCHANGE`` bitset NETIF_F_NEVER_CHANGE + ==================================== ====== ========================== + +Bitmaps in kernel response have the same meaning as bitmaps used in ioctl +interference but attribute names are different (they are based on +corresponding members of struct net_device). Legacy "flags" are not provided, +if userspace needs them (most likely only ethtool for backward compatibility), +it can calculate their values from related feature bits itself. +ETHA_FEATURES_HW uses mask consisting of all features recognized by kernel (to +provide all names when using verbose bitmap format), the other three use no +mask (simple bit lists). + + +FEATURES_SET +============ + +Request to set netdev features like ``ETHTOOL_SFEATURES`` ioctl request. + +Request contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_FEATURES_HEADER`` nested request header + ``ETHTOOL_A_FEATURES_WANTED`` bitset requested features + ==================================== ====== ========================== + +Kernel response contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_FEATURES_HEADER`` nested reply header + ``ETHTOOL_A_FEATURES_WANTED`` bitset diff wanted vs. result + ``ETHTOOL_A_FEATURES_ACTIVE`` bitset diff old vs. new active + ==================================== ====== ========================== + +Request contains only one bitset which can be either value/mask pair (request +to change specific feature bits and leave the rest) or only a value (request +to set all features to specified set). + +As request is subject to netdev_change_features() sanity checks, optional +kernel reply (can be suppressed by ``ETHTOOL_FLAG_OMIT_REPLY`` flag in request +header) informs client about the actual result. ``ETHTOOL_A_FEATURES_WANTED`` +reports the difference between client request and actual result: mask consists +of bits which differ between requested features and result (dev->features +after the operation), value consists of values of these bits in the request +(i.e. negated values from resulting features). ``ETHTOOL_A_FEATURES_ACTIVE`` +reports the difference between old and new dev->features: mask consists of +bits which have changed, values are their values in new dev->features (after +the operation). + +``ETHTOOL_MSG_FEATURES_NTF`` notification is sent not only if device features +are modified using ``ETHTOOL_MSG_FEATURES_SET`` request or on of ethtool ioctl +request but also each time features are modified with netdev_update_features() +or netdev_change_features(). + + +PRIVFLAGS_GET +============= + +Gets private flags like ``ETHTOOL_GPFLAGS`` ioctl request. + +Request contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_PRIVFLAGS_HEADER`` nested request header + ==================================== ====== ========================== + +Kernel response contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_PRIVFLAGS_HEADER`` nested reply header + ``ETHTOOL_A_PRIVFLAGS_FLAGS`` bitset private flags + ==================================== ====== ========================== + +``ETHTOOL_A_PRIVFLAGS_FLAGS`` is a bitset with values of device private flags. +These flags are defined by driver, their number and names (and also meaning) +are device dependent. For compact bitset format, names can be retrieved as +``ETH_SS_PRIV_FLAGS`` string set. If verbose bitset format is requested, +response uses all private flags supported by the device as mask so that client +gets the full information without having to fetch the string set with names. + + +PRIVFLAGS_SET +============= + +Sets or modifies values of device private flags like ``ETHTOOL_SPFLAGS`` +ioctl request. + +Request contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_PRIVFLAGS_HEADER`` nested request header + ``ETHTOOL_A_PRIVFLAGS_FLAGS`` bitset private flags + ==================================== ====== ========================== + +``ETHTOOL_A_PRIVFLAGS_FLAGS`` can either set the whole set of private flags or +modify only values of some of them. + + +RINGS_GET +========= + +Gets ring sizes like ``ETHTOOL_GRINGPARAM`` ioctl request. + +Request contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_RINGS_HEADER`` nested request header + ==================================== ====== ========================== + +Kernel response contents: + + ======================================= ====== =========================== + ``ETHTOOL_A_RINGS_HEADER`` nested reply header + ``ETHTOOL_A_RINGS_RX_MAX`` u32 max size of RX ring + ``ETHTOOL_A_RINGS_RX_MINI_MAX`` u32 max size of RX mini ring + ``ETHTOOL_A_RINGS_RX_JUMBO_MAX`` u32 max size of RX jumbo ring + ``ETHTOOL_A_RINGS_TX_MAX`` u32 max size of TX ring + ``ETHTOOL_A_RINGS_RX`` u32 size of RX ring + ``ETHTOOL_A_RINGS_RX_MINI`` u32 size of RX mini ring + ``ETHTOOL_A_RINGS_RX_JUMBO`` u32 size of RX jumbo ring + ``ETHTOOL_A_RINGS_TX`` u32 size of TX ring + ``ETHTOOL_A_RINGS_RX_BUF_LEN`` u32 size of buffers on the ring + ``ETHTOOL_A_RINGS_TCP_DATA_SPLIT`` u8 TCP header / data split + ``ETHTOOL_A_RINGS_CQE_SIZE`` u32 Size of TX/RX CQE + ``ETHTOOL_A_RINGS_TX_PUSH`` u8 flag of TX Push mode + ``ETHTOOL_A_RINGS_RX_PUSH`` u8 flag of RX Push mode + ``ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN`` u32 size of TX push buffer + ``ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN_MAX`` u32 max size of TX push buffer + ======================================= ====== =========================== + +``ETHTOOL_A_RINGS_TCP_DATA_SPLIT`` indicates whether the device is usable with +page-flipping TCP zero-copy receive (``getsockopt(TCP_ZEROCOPY_RECEIVE)``). +If enabled the device is configured to place frame headers and data into +separate buffers. The device configuration must make it possible to receive +full memory pages of data, for example because MTU is high enough or through +HW-GRO. + +``ETHTOOL_A_RINGS_[RX|TX]_PUSH`` flag is used to enable descriptor fast +path to send or receive packets. In ordinary path, driver fills descriptors in DRAM and +notifies NIC hardware. In fast path, driver pushes descriptors to the device +through MMIO writes, thus reducing the latency. However, enabling this feature +may increase the CPU cost. Drivers may enforce additional per-packet +eligibility checks (e.g. on packet size). + +``ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN`` specifies the maximum number of bytes of a +transmitted packet a driver can push directly to the underlying device +('push' mode). Pushing some of the payload bytes to the device has the +advantages of reducing latency for small packets by avoiding DMA mapping (same +as ``ETHTOOL_A_RINGS_TX_PUSH`` parameter) as well as allowing the underlying +device to process packet headers ahead of fetching its payload. +This can help the device to make fast actions based on the packet's headers. +This is similar to the "tx-copybreak" parameter, which copies the packet to a +preallocated DMA memory area instead of mapping new memory. However, +tx-push-buff parameter copies the packet directly to the device to allow the +device to take faster actions on the packet. + +RINGS_SET +========= + +Sets ring sizes like ``ETHTOOL_SRINGPARAM`` ioctl request. + +Request contents: + + ==================================== ====== =========================== + ``ETHTOOL_A_RINGS_HEADER`` nested reply header + ``ETHTOOL_A_RINGS_RX`` u32 size of RX ring + ``ETHTOOL_A_RINGS_RX_MINI`` u32 size of RX mini ring + ``ETHTOOL_A_RINGS_RX_JUMBO`` u32 size of RX jumbo ring + ``ETHTOOL_A_RINGS_TX`` u32 size of TX ring + ``ETHTOOL_A_RINGS_RX_BUF_LEN`` u32 size of buffers on the ring + ``ETHTOOL_A_RINGS_CQE_SIZE`` u32 Size of TX/RX CQE + ``ETHTOOL_A_RINGS_TX_PUSH`` u8 flag of TX Push mode + ``ETHTOOL_A_RINGS_RX_PUSH`` u8 flag of RX Push mode + ``ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN`` u32 size of TX push buffer + ==================================== ====== =========================== + +Kernel checks that requested ring sizes do not exceed limits reported by +driver. Driver may impose additional constraints and may not suspport all +attributes. + + +``ETHTOOL_A_RINGS_CQE_SIZE`` specifies the completion queue event size. +Completion queue events(CQE) are the events posted by NIC to indicate the +completion status of a packet when the packet is sent(like send success or +error) or received(like pointers to packet fragments). The CQE size parameter +enables to modify the CQE size other than default size if NIC supports it. +A bigger CQE can have more receive buffer pointers inturn NIC can transfer +a bigger frame from wire. Based on the NIC hardware, the overall completion +queue size can be adjusted in the driver if CQE size is modified. + +CHANNELS_GET +============ + +Gets channel counts like ``ETHTOOL_GCHANNELS`` ioctl request. + +Request contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_CHANNELS_HEADER`` nested request header + ==================================== ====== ========================== + +Kernel response contents: + + ===================================== ====== ========================== + ``ETHTOOL_A_CHANNELS_HEADER`` nested reply header + ``ETHTOOL_A_CHANNELS_RX_MAX`` u32 max receive channels + ``ETHTOOL_A_CHANNELS_TX_MAX`` u32 max transmit channels + ``ETHTOOL_A_CHANNELS_OTHER_MAX`` u32 max other channels + ``ETHTOOL_A_CHANNELS_COMBINED_MAX`` u32 max combined channels + ``ETHTOOL_A_CHANNELS_RX_COUNT`` u32 receive channel count + ``ETHTOOL_A_CHANNELS_TX_COUNT`` u32 transmit channel count + ``ETHTOOL_A_CHANNELS_OTHER_COUNT`` u32 other channel count + ``ETHTOOL_A_CHANNELS_COMBINED_COUNT`` u32 combined channel count + ===================================== ====== ========================== + + +CHANNELS_SET +============ + +Sets channel counts like ``ETHTOOL_SCHANNELS`` ioctl request. + +Request contents: + + ===================================== ====== ========================== + ``ETHTOOL_A_CHANNELS_HEADER`` nested request header + ``ETHTOOL_A_CHANNELS_RX_COUNT`` u32 receive channel count + ``ETHTOOL_A_CHANNELS_TX_COUNT`` u32 transmit channel count + ``ETHTOOL_A_CHANNELS_OTHER_COUNT`` u32 other channel count + ``ETHTOOL_A_CHANNELS_COMBINED_COUNT`` u32 combined channel count + ===================================== ====== ========================== + +Kernel checks that requested channel counts do not exceed limits reported by +driver. Driver may impose additional constraints and may not suspport all +attributes. + + +COALESCE_GET +============ + +Gets coalescing parameters like ``ETHTOOL_GCOALESCE`` ioctl request. + +Request contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_COALESCE_HEADER`` nested request header + ==================================== ====== ========================== + +Kernel response contents: + + =========================================== ====== ======================= + ``ETHTOOL_A_COALESCE_HEADER`` nested reply header + ``ETHTOOL_A_COALESCE_RX_USECS`` u32 delay (us), normal Rx + ``ETHTOOL_A_COALESCE_RX_MAX_FRAMES`` u32 max packets, normal Rx + ``ETHTOOL_A_COALESCE_RX_USECS_IRQ`` u32 delay (us), Rx in IRQ + ``ETHTOOL_A_COALESCE_RX_MAX_FRAMES_IRQ`` u32 max packets, Rx in IRQ + ``ETHTOOL_A_COALESCE_TX_USECS`` u32 delay (us), normal Tx + ``ETHTOOL_A_COALESCE_TX_MAX_FRAMES`` u32 max packets, normal Tx + ``ETHTOOL_A_COALESCE_TX_USECS_IRQ`` u32 delay (us), Tx in IRQ + ``ETHTOOL_A_COALESCE_TX_MAX_FRAMES_IRQ`` u32 IRQ packets, Tx in IRQ + ``ETHTOOL_A_COALESCE_STATS_BLOCK_USECS`` u32 delay of stats update + ``ETHTOOL_A_COALESCE_USE_ADAPTIVE_RX`` bool adaptive Rx coalesce + ``ETHTOOL_A_COALESCE_USE_ADAPTIVE_TX`` bool adaptive Tx coalesce + ``ETHTOOL_A_COALESCE_PKT_RATE_LOW`` u32 threshold for low rate + ``ETHTOOL_A_COALESCE_RX_USECS_LOW`` u32 delay (us), low Rx + ``ETHTOOL_A_COALESCE_RX_MAX_FRAMES_LOW`` u32 max packets, low Rx + ``ETHTOOL_A_COALESCE_TX_USECS_LOW`` u32 delay (us), low Tx + ``ETHTOOL_A_COALESCE_TX_MAX_FRAMES_LOW`` u32 max packets, low Tx + ``ETHTOOL_A_COALESCE_PKT_RATE_HIGH`` u32 threshold for high rate + ``ETHTOOL_A_COALESCE_RX_USECS_HIGH`` u32 delay (us), high Rx + ``ETHTOOL_A_COALESCE_RX_MAX_FRAMES_HIGH`` u32 max packets, high Rx + ``ETHTOOL_A_COALESCE_TX_USECS_HIGH`` u32 delay (us), high Tx + ``ETHTOOL_A_COALESCE_TX_MAX_FRAMES_HIGH`` u32 max packets, high Tx + ``ETHTOOL_A_COALESCE_RATE_SAMPLE_INTERVAL`` u32 rate sampling interval + ``ETHTOOL_A_COALESCE_USE_CQE_TX`` bool timer reset mode, Tx + ``ETHTOOL_A_COALESCE_USE_CQE_RX`` bool timer reset mode, Rx + ``ETHTOOL_A_COALESCE_TX_AGGR_MAX_BYTES`` u32 max aggr size, Tx + ``ETHTOOL_A_COALESCE_TX_AGGR_MAX_FRAMES`` u32 max aggr packets, Tx + ``ETHTOOL_A_COALESCE_TX_AGGR_TIME_USECS`` u32 time (us), aggr, Tx + =========================================== ====== ======================= + +Attributes are only included in reply if their value is not zero or the +corresponding bit in ``ethtool_ops::supported_coalesce_params`` is set (i.e. +they are declared as supported by driver). + +Timer reset mode (``ETHTOOL_A_COALESCE_USE_CQE_TX`` and +``ETHTOOL_A_COALESCE_USE_CQE_RX``) controls the interaction between packet +arrival and the various time based delay parameters. By default timers are +expected to limit the max delay between any packet arrival/departure and a +corresponding interrupt. In this mode timer should be started by packet +arrival (sometimes delivery of previous interrupt) and reset when interrupt +is delivered. +Setting the appropriate attribute to 1 will enable ``CQE`` mode, where +each packet event resets the timer. In this mode timer is used to force +the interrupt if queue goes idle, while busy queues depend on the packet +limit to trigger interrupts. + +Tx aggregation consists of copying frames into a contiguous buffer so that they +can be submitted as a single IO operation. ``ETHTOOL_A_COALESCE_TX_AGGR_MAX_BYTES`` +describes the maximum size in bytes for the submitted buffer. +``ETHTOOL_A_COALESCE_TX_AGGR_MAX_FRAMES`` describes the maximum number of frames +that can be aggregated into a single buffer. +``ETHTOOL_A_COALESCE_TX_AGGR_TIME_USECS`` describes the amount of time in usecs, +counted since the first packet arrival in an aggregated block, after which the +block should be sent. +This feature is mainly of interest for specific USB devices which does not cope +well with frequent small-sized URBs transmissions. + +COALESCE_SET +============ + +Sets coalescing parameters like ``ETHTOOL_SCOALESCE`` ioctl request. + +Request contents: + + =========================================== ====== ======================= + ``ETHTOOL_A_COALESCE_HEADER`` nested request header + ``ETHTOOL_A_COALESCE_RX_USECS`` u32 delay (us), normal Rx + ``ETHTOOL_A_COALESCE_RX_MAX_FRAMES`` u32 max packets, normal Rx + ``ETHTOOL_A_COALESCE_RX_USECS_IRQ`` u32 delay (us), Rx in IRQ + ``ETHTOOL_A_COALESCE_RX_MAX_FRAMES_IRQ`` u32 max packets, Rx in IRQ + ``ETHTOOL_A_COALESCE_TX_USECS`` u32 delay (us), normal Tx + ``ETHTOOL_A_COALESCE_TX_MAX_FRAMES`` u32 max packets, normal Tx + ``ETHTOOL_A_COALESCE_TX_USECS_IRQ`` u32 delay (us), Tx in IRQ + ``ETHTOOL_A_COALESCE_TX_MAX_FRAMES_IRQ`` u32 IRQ packets, Tx in IRQ + ``ETHTOOL_A_COALESCE_STATS_BLOCK_USECS`` u32 delay of stats update + ``ETHTOOL_A_COALESCE_USE_ADAPTIVE_RX`` bool adaptive Rx coalesce + ``ETHTOOL_A_COALESCE_USE_ADAPTIVE_TX`` bool adaptive Tx coalesce + ``ETHTOOL_A_COALESCE_PKT_RATE_LOW`` u32 threshold for low rate + ``ETHTOOL_A_COALESCE_RX_USECS_LOW`` u32 delay (us), low Rx + ``ETHTOOL_A_COALESCE_RX_MAX_FRAMES_LOW`` u32 max packets, low Rx + ``ETHTOOL_A_COALESCE_TX_USECS_LOW`` u32 delay (us), low Tx + ``ETHTOOL_A_COALESCE_TX_MAX_FRAMES_LOW`` u32 max packets, low Tx + ``ETHTOOL_A_COALESCE_PKT_RATE_HIGH`` u32 threshold for high rate + ``ETHTOOL_A_COALESCE_RX_USECS_HIGH`` u32 delay (us), high Rx + ``ETHTOOL_A_COALESCE_RX_MAX_FRAMES_HIGH`` u32 max packets, high Rx + ``ETHTOOL_A_COALESCE_TX_USECS_HIGH`` u32 delay (us), high Tx + ``ETHTOOL_A_COALESCE_TX_MAX_FRAMES_HIGH`` u32 max packets, high Tx + ``ETHTOOL_A_COALESCE_RATE_SAMPLE_INTERVAL`` u32 rate sampling interval + ``ETHTOOL_A_COALESCE_USE_CQE_TX`` bool timer reset mode, Tx + ``ETHTOOL_A_COALESCE_USE_CQE_RX`` bool timer reset mode, Rx + ``ETHTOOL_A_COALESCE_TX_AGGR_MAX_BYTES`` u32 max aggr size, Tx + ``ETHTOOL_A_COALESCE_TX_AGGR_MAX_FRAMES`` u32 max aggr packets, Tx + ``ETHTOOL_A_COALESCE_TX_AGGR_TIME_USECS`` u32 time (us), aggr, Tx + =========================================== ====== ======================= + +Request is rejected if it attributes declared as unsupported by driver (i.e. +such that the corresponding bit in ``ethtool_ops::supported_coalesce_params`` +is not set), regardless of their values. Driver may impose additional +constraints on coalescing parameters and their values. + +Compared to requests issued via the ``ioctl()`` netlink version of this request +will try harder to make sure that values specified by the user have been applied +and may call the driver twice. + + +PAUSE_GET +========= + +Gets pause frame settings like ``ETHTOOL_GPAUSEPARAM`` ioctl request. + +Request contents: + + ===================================== ====== ========================== + ``ETHTOOL_A_PAUSE_HEADER`` nested request header + ``ETHTOOL_A_PAUSE_STATS_SRC`` u32 source of statistics + ===================================== ====== ========================== + +``ETHTOOL_A_PAUSE_STATS_SRC`` is optional. It takes values from: + +.. kernel-doc:: include/uapi/linux/ethtool.h + :identifiers: ethtool_mac_stats_src + +If absent from the request, stats will be provided with +an ``ETHTOOL_A_PAUSE_STATS_SRC`` attribute in the response equal to +``ETHTOOL_MAC_STATS_SRC_AGGREGATE``. + +Kernel response contents: + + ===================================== ====== ========================== + ``ETHTOOL_A_PAUSE_HEADER`` nested request header + ``ETHTOOL_A_PAUSE_AUTONEG`` bool pause autonegotiation + ``ETHTOOL_A_PAUSE_RX`` bool receive pause frames + ``ETHTOOL_A_PAUSE_TX`` bool transmit pause frames + ``ETHTOOL_A_PAUSE_STATS`` nested pause statistics + ===================================== ====== ========================== + +``ETHTOOL_A_PAUSE_STATS`` are reported if ``ETHTOOL_FLAG_STATS`` was set +in ``ETHTOOL_A_HEADER_FLAGS``. +It will be empty if driver did not report any statistics. Drivers fill in +the statistics in the following structure: + +.. kernel-doc:: include/linux/ethtool.h + :identifiers: ethtool_pause_stats + +Each member has a corresponding attribute defined. + +PAUSE_SET +========= + +Sets pause parameters like ``ETHTOOL_GPAUSEPARAM`` ioctl request. + +Request contents: + + ===================================== ====== ========================== + ``ETHTOOL_A_PAUSE_HEADER`` nested request header + ``ETHTOOL_A_PAUSE_AUTONEG`` bool pause autonegotiation + ``ETHTOOL_A_PAUSE_RX`` bool receive pause frames + ``ETHTOOL_A_PAUSE_TX`` bool transmit pause frames + ===================================== ====== ========================== + + +EEE_GET +======= + +Gets Energy Efficient Ethernet settings like ``ETHTOOL_GEEE`` ioctl request. + +Request contents: + + ===================================== ====== ========================== + ``ETHTOOL_A_EEE_HEADER`` nested request header + ===================================== ====== ========================== + +Kernel response contents: + + ===================================== ====== ========================== + ``ETHTOOL_A_EEE_HEADER`` nested request header + ``ETHTOOL_A_EEE_MODES_OURS`` bool supported/advertised modes + ``ETHTOOL_A_EEE_MODES_PEER`` bool peer advertised link modes + ``ETHTOOL_A_EEE_ACTIVE`` bool EEE is actively used + ``ETHTOOL_A_EEE_ENABLED`` bool EEE is enabled + ``ETHTOOL_A_EEE_TX_LPI_ENABLED`` bool Tx lpi enabled + ``ETHTOOL_A_EEE_TX_LPI_TIMER`` u32 Tx lpi timeout (in us) + ===================================== ====== ========================== + +In ``ETHTOOL_A_EEE_MODES_OURS``, mask consists of link modes for which EEE is +enabled, value of link modes for which EEE is advertised. Link modes for which +peer advertises EEE are listed in ``ETHTOOL_A_EEE_MODES_PEER`` (no mask). The +netlink interface allows reporting EEE status for all link modes but only +first 32 are provided by the ``ethtool_ops`` callback. + + +EEE_SET +======= + +Sets Energy Efficient Ethernet parameters like ``ETHTOOL_SEEE`` ioctl request. + +Request contents: + + ===================================== ====== ========================== + ``ETHTOOL_A_EEE_HEADER`` nested request header + ``ETHTOOL_A_EEE_MODES_OURS`` bool advertised modes + ``ETHTOOL_A_EEE_ENABLED`` bool EEE is enabled + ``ETHTOOL_A_EEE_TX_LPI_ENABLED`` bool Tx lpi enabled + ``ETHTOOL_A_EEE_TX_LPI_TIMER`` u32 Tx lpi timeout (in us) + ===================================== ====== ========================== + +``ETHTOOL_A_EEE_MODES_OURS`` is used to either list link modes to advertise +EEE for (if there is no mask) or specify changes to the list (if there is +a mask). The netlink interface allows reporting EEE status for all link modes +but only first 32 can be set at the moment as that is what the ``ethtool_ops`` +callback supports. + + +TSINFO_GET +========== + +Gets timestamping information like ``ETHTOOL_GET_TS_INFO`` ioctl request. + +Request contents: + + ===================================== ====== ========================== + ``ETHTOOL_A_TSINFO_HEADER`` nested request header + ===================================== ====== ========================== + +Kernel response contents: + + ===================================== ====== ========================== + ``ETHTOOL_A_TSINFO_HEADER`` nested request header + ``ETHTOOL_A_TSINFO_TIMESTAMPING`` bitset SO_TIMESTAMPING flags + ``ETHTOOL_A_TSINFO_TX_TYPES`` bitset supported Tx types + ``ETHTOOL_A_TSINFO_RX_FILTERS`` bitset supported Rx filters + ``ETHTOOL_A_TSINFO_PHC_INDEX`` u32 PTP hw clock index + ===================================== ====== ========================== + +``ETHTOOL_A_TSINFO_PHC_INDEX`` is absent if there is no associated PHC (there +is no special value for this case). The bitset attributes are omitted if they +would be empty (no bit set). + +CABLE_TEST +========== + +Start a cable test. + +Request contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_CABLE_TEST_HEADER`` nested request header + ==================================== ====== ========================== + +Notification contents: + +An Ethernet cable typically contains 1, 2 or 4 pairs. The length of +the pair can only be measured when there is a fault in the pair and +hence a reflection. Information about the fault may not be available, +depending on the specific hardware. Hence the contents of the notify +message are mostly optional. The attributes can be repeated an +arbitrary number of times, in an arbitrary order, for an arbitrary +number of pairs. + +The example shows the notification sent when the test is completed for +a T2 cable, i.e. two pairs. One pair is OK and hence has no length +information. The second pair has a fault and does have length +information. + + +---------------------------------------------+--------+---------------------+ + | ``ETHTOOL_A_CABLE_TEST_HEADER`` | nested | reply header | + +---------------------------------------------+--------+---------------------+ + | ``ETHTOOL_A_CABLE_TEST_STATUS`` | u8 | completed | + +---------------------------------------------+--------+---------------------+ + | ``ETHTOOL_A_CABLE_TEST_NTF_NEST`` | nested | all the results | + +-+-------------------------------------------+--------+---------------------+ + | | ``ETHTOOL_A_CABLE_NEST_RESULT`` | nested | cable test result | + +-+-+-----------------------------------------+--------+---------------------+ + | | | ``ETHTOOL_A_CABLE_RESULTS_PAIR`` | u8 | pair number | + +-+-+-----------------------------------------+--------+---------------------+ + | | | ``ETHTOOL_A_CABLE_RESULTS_CODE`` | u8 | result code | + +-+-+-----------------------------------------+--------+---------------------+ + | | ``ETHTOOL_A_CABLE_NEST_RESULT`` | nested | cable test results | + +-+-+-----------------------------------------+--------+---------------------+ + | | | ``ETHTOOL_A_CABLE_RESULTS_PAIR`` | u8 | pair number | + +-+-+-----------------------------------------+--------+---------------------+ + | | | ``ETHTOOL_A_CABLE_RESULTS_CODE`` | u8 | result code | + +-+-+-----------------------------------------+--------+---------------------+ + | | ``ETHTOOL_A_CABLE_NEST_FAULT_LENGTH`` | nested | cable length | + +-+-+-----------------------------------------+--------+---------------------+ + | | | ``ETHTOOL_A_CABLE_FAULT_LENGTH_PAIR`` | u8 | pair number | + +-+-+-----------------------------------------+--------+---------------------+ + | | | ``ETHTOOL_A_CABLE_FAULT_LENGTH_CM`` | u32 | length in cm | + +-+-+-----------------------------------------+--------+---------------------+ + +CABLE_TEST TDR +============== + +Start a cable test and report raw TDR data + +Request contents: + + +--------------------------------------------+--------+-----------------------+ + | ``ETHTOOL_A_CABLE_TEST_TDR_HEADER`` | nested | reply header | + +--------------------------------------------+--------+-----------------------+ + | ``ETHTOOL_A_CABLE_TEST_TDR_CFG`` | nested | test configuration | + +-+------------------------------------------+--------+-----------------------+ + | | ``ETHTOOL_A_CABLE_STEP_FIRST_DISTANCE`` | u32 | first data distance | + +-+-+----------------------------------------+--------+-----------------------+ + | | ``ETHTOOL_A_CABLE_STEP_LAST_DISTANCE`` | u32 | last data distance | + +-+-+----------------------------------------+--------+-----------------------+ + | | ``ETHTOOL_A_CABLE_STEP_STEP_DISTANCE`` | u32 | distance of each step | + +-+-+----------------------------------------+--------+-----------------------+ + | | ``ETHTOOL_A_CABLE_TEST_TDR_CFG_PAIR`` | u8 | pair to test | + +-+-+----------------------------------------+--------+-----------------------+ + +The ETHTOOL_A_CABLE_TEST_TDR_CFG is optional, as well as all members +of the nest. All distances are expressed in centimeters. The PHY takes +the distances as a guide, and rounds to the nearest distance it +actually supports. If a pair is passed, only that one pair will be +tested. Otherwise all pairs are tested. + +Notification contents: + +Raw TDR data is gathered by sending a pulse down the cable and +recording the amplitude of the reflected pulse for a given distance. + +It can take a number of seconds to collect TDR data, especial if the +full 100 meters is probed at 1 meter intervals. When the test is +started a notification will be sent containing just +ETHTOOL_A_CABLE_TEST_TDR_STATUS with the value +ETHTOOL_A_CABLE_TEST_NTF_STATUS_STARTED. + +When the test has completed a second notification will be sent +containing ETHTOOL_A_CABLE_TEST_TDR_STATUS with the value +ETHTOOL_A_CABLE_TEST_NTF_STATUS_COMPLETED and the TDR data. + +The message may optionally contain the amplitude of the pulse send +down the cable. This is measured in mV. A reflection should not be +bigger than transmitted pulse. + +Before the raw TDR data should be an ETHTOOL_A_CABLE_TDR_NEST_STEP +nest containing information about the distance along the cable for the +first reading, the last reading, and the step between each +reading. Distances are measured in centimeters. These should be the +exact values the PHY used. These may be different to what the user +requested, if the native measurement resolution is greater than 1 cm. + +For each step along the cable, a ETHTOOL_A_CABLE_TDR_NEST_AMPLITUDE is +used to report the amplitude of the reflection for a given pair. + + +---------------------------------------------+--------+----------------------+ + | ``ETHTOOL_A_CABLE_TEST_TDR_HEADER`` | nested | reply header | + +---------------------------------------------+--------+----------------------+ + | ``ETHTOOL_A_CABLE_TEST_TDR_STATUS`` | u8 | completed | + +---------------------------------------------+--------+----------------------+ + | ``ETHTOOL_A_CABLE_TEST_TDR_NTF_NEST`` | nested | all the results | + +-+-------------------------------------------+--------+----------------------+ + | | ``ETHTOOL_A_CABLE_TDR_NEST_PULSE`` | nested | TX Pulse amplitude | + +-+-+-----------------------------------------+--------+----------------------+ + | | | ``ETHTOOL_A_CABLE_PULSE_mV`` | s16 | Pulse amplitude | + +-+-+-----------------------------------------+--------+----------------------+ + | | ``ETHTOOL_A_CABLE_NEST_STEP`` | nested | TDR step info | + +-+-+-----------------------------------------+--------+----------------------+ + | | | ``ETHTOOL_A_CABLE_STEP_FIRST_DISTANCE`` | u32 | First data distance | + +-+-+-----------------------------------------+--------+----------------------+ + | | | ``ETHTOOL_A_CABLE_STEP_LAST_DISTANCE`` | u32 | Last data distance | + +-+-+-----------------------------------------+--------+----------------------+ + | | | ``ETHTOOL_A_CABLE_STEP_STEP_DISTANCE`` | u32 | distance of each step| + +-+-+-----------------------------------------+--------+----------------------+ + | | ``ETHTOOL_A_CABLE_TDR_NEST_AMPLITUDE`` | nested | Reflection amplitude | + +-+-+-----------------------------------------+--------+----------------------+ + | | | ``ETHTOOL_A_CABLE_RESULTS_PAIR`` | u8 | pair number | + +-+-+-----------------------------------------+--------+----------------------+ + | | | ``ETHTOOL_A_CABLE_AMPLITUDE_mV`` | s16 | Reflection amplitude | + +-+-+-----------------------------------------+--------+----------------------+ + | | ``ETHTOOL_A_CABLE_TDR_NEST_AMPLITUDE`` | nested | Reflection amplitude | + +-+-+-----------------------------------------+--------+----------------------+ + | | | ``ETHTOOL_A_CABLE_RESULTS_PAIR`` | u8 | pair number | + +-+-+-----------------------------------------+--------+----------------------+ + | | | ``ETHTOOL_A_CABLE_AMPLITUDE_mV`` | s16 | Reflection amplitude | + +-+-+-----------------------------------------+--------+----------------------+ + | | ``ETHTOOL_A_CABLE_TDR_NEST_AMPLITUDE`` | nested | Reflection amplitude | + +-+-+-----------------------------------------+--------+----------------------+ + | | | ``ETHTOOL_A_CABLE_RESULTS_PAIR`` | u8 | pair number | + +-+-+-----------------------------------------+--------+----------------------+ + | | | ``ETHTOOL_A_CABLE_AMPLITUDE_mV`` | s16 | Reflection amplitude | + +-+-+-----------------------------------------+--------+----------------------+ + +TUNNEL_INFO +=========== + +Gets information about the tunnel state NIC is aware of. + +Request contents: + + ===================================== ====== ========================== + ``ETHTOOL_A_TUNNEL_INFO_HEADER`` nested request header + ===================================== ====== ========================== + +Kernel response contents: + + +---------------------------------------------+--------+---------------------+ + | ``ETHTOOL_A_TUNNEL_INFO_HEADER`` | nested | reply header | + +---------------------------------------------+--------+---------------------+ + | ``ETHTOOL_A_TUNNEL_INFO_UDP_PORTS`` | nested | all UDP port tables | + +-+-------------------------------------------+--------+---------------------+ + | | ``ETHTOOL_A_TUNNEL_UDP_TABLE`` | nested | one UDP port table | + +-+-+-----------------------------------------+--------+---------------------+ + | | | ``ETHTOOL_A_TUNNEL_UDP_TABLE_SIZE`` | u32 | max size of the | + | | | | | table | + +-+-+-----------------------------------------+--------+---------------------+ + | | | ``ETHTOOL_A_TUNNEL_UDP_TABLE_TYPES`` | bitset | tunnel types which | + | | | | | table can hold | + +-+-+-----------------------------------------+--------+---------------------+ + | | | ``ETHTOOL_A_TUNNEL_UDP_TABLE_ENTRY`` | nested | offloaded UDP port | + +-+-+-+---------------------------------------+--------+---------------------+ + | | | | ``ETHTOOL_A_TUNNEL_UDP_ENTRY_PORT`` | be16 | UDP port | + +-+-+-+---------------------------------------+--------+---------------------+ + | | | | ``ETHTOOL_A_TUNNEL_UDP_ENTRY_TYPE`` | u32 | tunnel type | + +-+-+-+---------------------------------------+--------+---------------------+ + +For UDP tunnel table empty ``ETHTOOL_A_TUNNEL_UDP_TABLE_TYPES`` indicates that +the table contains static entries, hard-coded by the NIC. + +FEC_GET +======= + +Gets FEC configuration and state like ``ETHTOOL_GFECPARAM`` ioctl request. + +Request contents: + + ===================================== ====== ========================== + ``ETHTOOL_A_FEC_HEADER`` nested request header + ===================================== ====== ========================== + +Kernel response contents: + + ===================================== ====== ========================== + ``ETHTOOL_A_FEC_HEADER`` nested request header + ``ETHTOOL_A_FEC_MODES`` bitset configured modes + ``ETHTOOL_A_FEC_AUTO`` bool FEC mode auto selection + ``ETHTOOL_A_FEC_ACTIVE`` u32 index of active FEC mode + ``ETHTOOL_A_FEC_STATS`` nested FEC statistics + ===================================== ====== ========================== + +``ETHTOOL_A_FEC_ACTIVE`` is the bit index of the FEC link mode currently +active on the interface. This attribute may not be present if device does +not support FEC. + +``ETHTOOL_A_FEC_MODES`` and ``ETHTOOL_A_FEC_AUTO`` are only meaningful when +autonegotiation is disabled. If ``ETHTOOL_A_FEC_AUTO`` is non-zero driver will +select the FEC mode automatically based on the parameters of the SFP module. +This is equivalent to the ``ETHTOOL_FEC_AUTO`` bit of the ioctl interface. +``ETHTOOL_A_FEC_MODES`` carry the current FEC configuration using link mode +bits (rather than old ``ETHTOOL_FEC_*`` bits). + +``ETHTOOL_A_FEC_STATS`` are reported if ``ETHTOOL_FLAG_STATS`` was set in +``ETHTOOL_A_HEADER_FLAGS``. +Each attribute carries an array of 64bit statistics. First entry in the array +contains the total number of events on the port, while the following entries +are counters corresponding to lanes/PCS instances. The number of entries in +the array will be: + ++--------------+---------------------------------------------+ +| `0` | device does not support FEC statistics | ++--------------+---------------------------------------------+ +| `1` | device does not support per-lane break down | ++--------------+---------------------------------------------+ +| `1 + #lanes` | device has full support for FEC stats | ++--------------+---------------------------------------------+ + +Drivers fill in the statistics in the following structure: + +.. kernel-doc:: include/linux/ethtool.h + :identifiers: ethtool_fec_stats + +FEC_SET +======= + +Sets FEC parameters like ``ETHTOOL_SFECPARAM`` ioctl request. + +Request contents: + + ===================================== ====== ========================== + ``ETHTOOL_A_FEC_HEADER`` nested request header + ``ETHTOOL_A_FEC_MODES`` bitset configured modes + ``ETHTOOL_A_FEC_AUTO`` bool FEC mode auto selection + ===================================== ====== ========================== + +``FEC_SET`` is only meaningful when autonegotiation is disabled. Otherwise +FEC mode is selected as part of autonegotiation. + +``ETHTOOL_A_FEC_MODES`` selects which FEC mode should be used. It's recommended +to set only one bit, if multiple bits are set driver may choose between them +in an implementation specific way. + +``ETHTOOL_A_FEC_AUTO`` requests the driver to choose FEC mode based on SFP +module parameters. This does not mean autonegotiation. + +MODULE_EEPROM_GET +================= + +Fetch module EEPROM data dump. +This interface is designed to allow dumps of at most 1/2 page at once. This +means only dumps of 128 (or less) bytes are allowed, without crossing half page +boundary located at offset 128. For pages other than 0 only high 128 bytes are +accessible. + +Request contents: + + ======================================= ====== ========================== + ``ETHTOOL_A_MODULE_EEPROM_HEADER`` nested request header + ``ETHTOOL_A_MODULE_EEPROM_OFFSET`` u32 offset within a page + ``ETHTOOL_A_MODULE_EEPROM_LENGTH`` u32 amount of bytes to read + ``ETHTOOL_A_MODULE_EEPROM_PAGE`` u8 page number + ``ETHTOOL_A_MODULE_EEPROM_BANK`` u8 bank number + ``ETHTOOL_A_MODULE_EEPROM_I2C_ADDRESS`` u8 page I2C address + ======================================= ====== ========================== + +If ``ETHTOOL_A_MODULE_EEPROM_BANK`` is not specified, bank 0 is assumed. + +Kernel response contents: + + +---------------------------------------------+--------+---------------------+ + | ``ETHTOOL_A_MODULE_EEPROM_HEADER`` | nested | reply header | + +---------------------------------------------+--------+---------------------+ + | ``ETHTOOL_A_MODULE_EEPROM_DATA`` | binary | array of bytes from | + | | | module EEPROM | + +---------------------------------------------+--------+---------------------+ + +``ETHTOOL_A_MODULE_EEPROM_DATA`` has an attribute length equal to the amount of +bytes driver actually read. + +STATS_GET +========= + +Get standard statistics for the interface. Note that this is not +a re-implementation of ``ETHTOOL_GSTATS`` which exposed driver-defined +stats. + +Request contents: + + ======================================= ====== ========================== + ``ETHTOOL_A_STATS_HEADER`` nested request header + ``ETHTOOL_A_STATS_SRC`` u32 source of statistics + ``ETHTOOL_A_STATS_GROUPS`` bitset requested groups of stats + ======================================= ====== ========================== + +Kernel response contents: + + +-----------------------------------+--------+--------------------------------+ + | ``ETHTOOL_A_STATS_HEADER`` | nested | reply header | + +-----------------------------------+--------+--------------------------------+ + | ``ETHTOOL_A_STATS_SRC`` | u32 | source of statistics | + +-----------------------------------+--------+--------------------------------+ + | ``ETHTOOL_A_STATS_GRP`` | nested | one or more group of stats | + +-+---------------------------------+--------+--------------------------------+ + | | ``ETHTOOL_A_STATS_GRP_ID`` | u32 | group ID - ``ETHTOOL_STATS_*`` | + +-+---------------------------------+--------+--------------------------------+ + | | ``ETHTOOL_A_STATS_GRP_SS_ID`` | u32 | string set ID for names | + +-+---------------------------------+--------+--------------------------------+ + | | ``ETHTOOL_A_STATS_GRP_STAT`` | nested | nest containing a statistic | + +-+---------------------------------+--------+--------------------------------+ + | | ``ETHTOOL_A_STATS_GRP_HIST_RX`` | nested | histogram statistic (Rx) | + +-+---------------------------------+--------+--------------------------------+ + | | ``ETHTOOL_A_STATS_GRP_HIST_TX`` | nested | histogram statistic (Tx) | + +-+---------------------------------+--------+--------------------------------+ + +Users specify which groups of statistics they are requesting via +the ``ETHTOOL_A_STATS_GROUPS`` bitset. Currently defined values are: + + ====================== ======== =============================================== + ETHTOOL_STATS_ETH_MAC eth-mac Basic IEEE 802.3 MAC statistics (30.3.1.1.*) + ETHTOOL_STATS_ETH_PHY eth-phy Basic IEEE 802.3 PHY statistics (30.3.2.1.*) + ETHTOOL_STATS_ETH_CTRL eth-ctrl Basic IEEE 802.3 MAC Ctrl statistics (30.3.3.*) + ETHTOOL_STATS_RMON rmon RMON (RFC 2819) statistics + ====================== ======== =============================================== + +Each group should have a corresponding ``ETHTOOL_A_STATS_GRP`` in the reply. +``ETHTOOL_A_STATS_GRP_ID`` identifies which group's statistics nest contains. +``ETHTOOL_A_STATS_GRP_SS_ID`` identifies the string set ID for the names of +the statistics in the group, if available. + +Statistics are added to the ``ETHTOOL_A_STATS_GRP`` nest under +``ETHTOOL_A_STATS_GRP_STAT``. ``ETHTOOL_A_STATS_GRP_STAT`` should contain +single 8 byte (u64) attribute inside - the type of that attribute is +the statistic ID and the value is the value of the statistic. +Each group has its own interpretation of statistic IDs. +Attribute IDs correspond to strings from the string set identified +by ``ETHTOOL_A_STATS_GRP_SS_ID``. Complex statistics (such as RMON histogram +entries) are also listed inside ``ETHTOOL_A_STATS_GRP`` and do not have +a string defined in the string set. + +RMON "histogram" counters count number of packets within given size range. +Because RFC does not specify the ranges beyond the standard 1518 MTU devices +differ in definition of buckets. For this reason the definition of packet ranges +is left to each driver. + +``ETHTOOL_A_STATS_GRP_HIST_RX`` and ``ETHTOOL_A_STATS_GRP_HIST_TX`` nests +contain the following attributes: + + ================================= ====== =================================== + ETHTOOL_A_STATS_RMON_HIST_BKT_LOW u32 low bound of the packet size bucket + ETHTOOL_A_STATS_RMON_HIST_BKT_HI u32 high bound of the bucket + ETHTOOL_A_STATS_RMON_HIST_VAL u64 packet counter + ================================= ====== =================================== + +Low and high bounds are inclusive, for example: + + ============================= ==== ==== + RFC statistic low high + ============================= ==== ==== + etherStatsPkts64Octets 0 64 + etherStatsPkts512to1023Octets 512 1023 + ============================= ==== ==== + +``ETHTOOL_A_STATS_SRC`` is optional. Similar to ``PAUSE_GET``, it takes values +from ``enum ethtool_mac_stats_src``. If absent from the request, stats will be +provided with an ``ETHTOOL_A_STATS_SRC`` attribute in the response equal to +``ETHTOOL_MAC_STATS_SRC_AGGREGATE``. + +PHC_VCLOCKS_GET +=============== + +Query device PHC virtual clocks information. + +Request contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_PHC_VCLOCKS_HEADER`` nested request header + ==================================== ====== ========================== + +Kernel response contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_PHC_VCLOCKS_HEADER`` nested reply header + ``ETHTOOL_A_PHC_VCLOCKS_NUM`` u32 PHC virtual clocks number + ``ETHTOOL_A_PHC_VCLOCKS_INDEX`` s32 PHC index array + ==================================== ====== ========================== + +MODULE_GET +========== + +Gets transceiver module parameters. + +Request contents: + + ===================================== ====== ========================== + ``ETHTOOL_A_MODULE_HEADER`` nested request header + ===================================== ====== ========================== + +Kernel response contents: + + ====================================== ====== ========================== + ``ETHTOOL_A_MODULE_HEADER`` nested reply header + ``ETHTOOL_A_MODULE_POWER_MODE_POLICY`` u8 power mode policy + ``ETHTOOL_A_MODULE_POWER_MODE`` u8 operational power mode + ====================================== ====== ========================== + +The optional ``ETHTOOL_A_MODULE_POWER_MODE_POLICY`` attribute encodes the +transceiver module power mode policy enforced by the host. The default policy +is driver-dependent, but "auto" is the recommended default and it should be +implemented by new drivers and drivers where conformance to a legacy behavior +is not critical. + +The optional ``ETHTHOOL_A_MODULE_POWER_MODE`` attribute encodes the operational +power mode policy of the transceiver module. It is only reported when a module +is plugged-in. Possible values are: + +.. kernel-doc:: include/uapi/linux/ethtool.h + :identifiers: ethtool_module_power_mode + +MODULE_SET +========== + +Sets transceiver module parameters. + +Request contents: + + ====================================== ====== ========================== + ``ETHTOOL_A_MODULE_HEADER`` nested request header + ``ETHTOOL_A_MODULE_POWER_MODE_POLICY`` u8 power mode policy + ====================================== ====== ========================== + +When set, the optional ``ETHTOOL_A_MODULE_POWER_MODE_POLICY`` attribute is used +to set the transceiver module power policy enforced by the host. Possible +values are: + +.. kernel-doc:: include/uapi/linux/ethtool.h + :identifiers: ethtool_module_power_mode_policy + +For SFF-8636 modules, low power mode is forced by the host according to table +6-10 in revision 2.10a of the specification. + +For CMIS modules, low power mode is forced by the host according to table 6-12 +in revision 5.0 of the specification. + +PSE_GET +======= + +Gets PSE attributes. + +Request contents: + + ===================================== ====== ========================== + ``ETHTOOL_A_PSE_HEADER`` nested request header + ===================================== ====== ========================== + +Kernel response contents: + + ====================================== ====== ============================= + ``ETHTOOL_A_PSE_HEADER`` nested reply header + ``ETHTOOL_A_PODL_PSE_ADMIN_STATE`` u32 Operational state of the PoDL + PSE functions + ``ETHTOOL_A_PODL_PSE_PW_D_STATUS`` u32 power detection status of the + PoDL PSE. + ====================================== ====== ============================= + +When set, the optional ``ETHTOOL_A_PODL_PSE_ADMIN_STATE`` attribute identifies +the operational state of the PoDL PSE functions. The operational state of the +PSE function can be changed using the ``ETHTOOL_A_PODL_PSE_ADMIN_CONTROL`` +action. This option is corresponding to ``IEEE 802.3-2018`` 30.15.1.1.2 +aPoDLPSEAdminState. Possible values are: + +.. kernel-doc:: include/uapi/linux/ethtool.h + :identifiers: ethtool_podl_pse_admin_state + +When set, the optional ``ETHTOOL_A_PODL_PSE_PW_D_STATUS`` attribute identifies +the power detection status of the PoDL PSE. The status depend on internal PSE +state machine and automatic PD classification support. This option is +corresponding to ``IEEE 802.3-2018`` 30.15.1.1.3 aPoDLPSEPowerDetectionStatus. +Possible values are: + +.. kernel-doc:: include/uapi/linux/ethtool.h + :identifiers: ethtool_podl_pse_pw_d_status + +PSE_SET +======= + +Sets PSE parameters. + +Request contents: + + ====================================== ====== ============================= + ``ETHTOOL_A_PSE_HEADER`` nested request header + ``ETHTOOL_A_PODL_PSE_ADMIN_CONTROL`` u32 Control PoDL PSE Admin state + ====================================== ====== ============================= + +When set, the optional ``ETHTOOL_A_PODL_PSE_ADMIN_CONTROL`` attribute is used +to control PoDL PSE Admin functions. This option is implementing +``IEEE 802.3-2018`` 30.15.1.2.1 acPoDLPSEAdminControl. See +``ETHTOOL_A_PODL_PSE_ADMIN_STATE`` for supported values. + +RSS_GET +======= + +Get indirection table, hash key and hash function info associated with a +RSS context of an interface similar to ``ETHTOOL_GRSSH`` ioctl request. + +Request contents: + +===================================== ====== ========================== + ``ETHTOOL_A_RSS_HEADER`` nested request header + ``ETHTOOL_A_RSS_CONTEXT`` u32 context number +===================================== ====== ========================== + +Kernel response contents: + +===================================== ====== ========================== + ``ETHTOOL_A_RSS_HEADER`` nested reply header + ``ETHTOOL_A_RSS_HFUNC`` u32 RSS hash func + ``ETHTOOL_A_RSS_INDIR`` binary Indir table bytes + ``ETHTOOL_A_RSS_HKEY`` binary Hash key bytes +===================================== ====== ========================== + +ETHTOOL_A_RSS_HFUNC attribute is bitmap indicating the hash function +being used. Current supported options are toeplitz, xor or crc32. +ETHTOOL_A_RSS_INDIR attribute returns RSS indrection table where each byte +indicates queue number. + +PLCA_GET_CFG +============ + +Gets the IEEE 802.3cg-2019 Clause 148 Physical Layer Collision Avoidance +(PLCA) Reconciliation Sublayer (RS) attributes. + +Request contents: + + ===================================== ====== ========================== + ``ETHTOOL_A_PLCA_HEADER`` nested request header + ===================================== ====== ========================== + +Kernel response contents: + + ====================================== ====== ============================= + ``ETHTOOL_A_PLCA_HEADER`` nested reply header + ``ETHTOOL_A_PLCA_VERSION`` u16 Supported PLCA management + interface standard/version + ``ETHTOOL_A_PLCA_ENABLED`` u8 PLCA Admin State + ``ETHTOOL_A_PLCA_NODE_ID`` u32 PLCA unique local node ID + ``ETHTOOL_A_PLCA_NODE_CNT`` u32 Number of PLCA nodes on the + network, including the + coordinator + ``ETHTOOL_A_PLCA_TO_TMR`` u32 Transmit Opportunity Timer + value in bit-times (BT) + ``ETHTOOL_A_PLCA_BURST_CNT`` u32 Number of additional packets + the node is allowed to send + within a single TO + ``ETHTOOL_A_PLCA_BURST_TMR`` u32 Time to wait for the MAC to + transmit a new frame before + terminating the burst + ====================================== ====== ============================= + +When set, the optional ``ETHTOOL_A_PLCA_VERSION`` attribute indicates which +standard and version the PLCA management interface complies to. When not set, +the interface is vendor-specific and (possibly) supplied by the driver. +The OPEN Alliance SIG specifies a standard register map for 10BASE-T1S PHYs +embedding the PLCA Reconcialiation Sublayer. See "10BASE-T1S PLCA Management +Registers" at https://www.opensig.org/about/specifications/. + +When set, the optional ``ETHTOOL_A_PLCA_ENABLED`` attribute indicates the +administrative state of the PLCA RS. When not set, the node operates in "plain" +CSMA/CD mode. This option is corresponding to ``IEEE 802.3cg-2019`` 30.16.1.1.1 +aPLCAAdminState / 30.16.1.2.1 acPLCAAdminControl. + +When set, the optional ``ETHTOOL_A_PLCA_NODE_ID`` attribute indicates the +configured local node ID of the PHY. This ID determines which transmit +opportunity (TO) is reserved for the node to transmit into. This option is +corresponding to ``IEEE 802.3cg-2019`` 30.16.1.1.4 aPLCALocalNodeID. The valid +range for this attribute is [0 .. 255] where 255 means "not configured". + +When set, the optional ``ETHTOOL_A_PLCA_NODE_CNT`` attribute indicates the +configured maximum number of PLCA nodes on the mixing-segment. This number +determines the total number of transmit opportunities generated during a +PLCA cycle. This attribute is relevant only for the PLCA coordinator, which is +the node with aPLCALocalNodeID set to 0. Follower nodes ignore this setting. +This option is corresponding to ``IEEE 802.3cg-2019`` 30.16.1.1.3 +aPLCANodeCount. The valid range for this attribute is [1 .. 255]. + +When set, the optional ``ETHTOOL_A_PLCA_TO_TMR`` attribute indicates the +configured value of the transmit opportunity timer in bit-times. This value +must be set equal across all nodes sharing the medium for PLCA to work +correctly. This option is corresponding to ``IEEE 802.3cg-2019`` 30.16.1.1.5 +aPLCATransmitOpportunityTimer. The valid range for this attribute is +[0 .. 255]. + +When set, the optional ``ETHTOOL_A_PLCA_BURST_CNT`` attribute indicates the +configured number of extra packets that the node is allowed to send during a +single transmit opportunity. By default, this attribute is 0, meaning that +the node can only send a single frame per TO. When greater than 0, the PLCA RS +keeps the TO after any transmission, waiting for the MAC to send a new frame +for up to aPLCABurstTimer BTs. This can only happen a number of times per PLCA +cycle up to the value of this parameter. After that, the burst is over and the +normal counting of TOs resumes. This option is corresponding to +``IEEE 802.3cg-2019`` 30.16.1.1.6 aPLCAMaxBurstCount. The valid range for this +attribute is [0 .. 255]. + +When set, the optional ``ETHTOOL_A_PLCA_BURST_TMR`` attribute indicates how +many bit-times the PLCA RS waits for the MAC to initiate a new transmission +when aPLCAMaxBurstCount is greater than 0. If the MAC fails to send a new +frame within this time, the burst ends and the counting of TOs resumes. +Otherwise, the new frame is sent as part of the current burst. This option +is corresponding to ``IEEE 802.3cg-2019`` 30.16.1.1.7 aPLCABurstTimer. The +valid range for this attribute is [0 .. 255]. Although, the value should be +set greater than the Inter-Frame-Gap (IFG) time of the MAC (plus some margin) +for PLCA burst mode to work as intended. + +PLCA_SET_CFG +============ + +Sets PLCA RS parameters. + +Request contents: + + ====================================== ====== ============================= + ``ETHTOOL_A_PLCA_HEADER`` nested request header + ``ETHTOOL_A_PLCA_ENABLED`` u8 PLCA Admin State + ``ETHTOOL_A_PLCA_NODE_ID`` u8 PLCA unique local node ID + ``ETHTOOL_A_PLCA_NODE_CNT`` u8 Number of PLCA nodes on the + netkork, including the + coordinator + ``ETHTOOL_A_PLCA_TO_TMR`` u8 Transmit Opportunity Timer + value in bit-times (BT) + ``ETHTOOL_A_PLCA_BURST_CNT`` u8 Number of additional packets + the node is allowed to send + within a single TO + ``ETHTOOL_A_PLCA_BURST_TMR`` u8 Time to wait for the MAC to + transmit a new frame before + terminating the burst + ====================================== ====== ============================= + +For a description of each attribute, see ``PLCA_GET_CFG``. + +PLCA_GET_STATUS +=============== + +Gets PLCA RS status information. + +Request contents: + + ===================================== ====== ========================== + ``ETHTOOL_A_PLCA_HEADER`` nested request header + ===================================== ====== ========================== + +Kernel response contents: + + ====================================== ====== ============================= + ``ETHTOOL_A_PLCA_HEADER`` nested reply header + ``ETHTOOL_A_PLCA_STATUS`` u8 PLCA RS operational status + ====================================== ====== ============================= + +When set, the ``ETHTOOL_A_PLCA_STATUS`` attribute indicates whether the node is +detecting the presence of the BEACON on the network. This flag is +corresponding to ``IEEE 802.3cg-2019`` 30.16.1.1.2 aPLCAStatus. + +MM_GET +====== + +Retrieve 802.3 MAC Merge parameters. + +Request contents: + + ==================================== ====== ========================== + ``ETHTOOL_A_MM_HEADER`` nested request header + ==================================== ====== ========================== + +Kernel response contents: + + ================================= ====== =================================== + ``ETHTOOL_A_MM_HEADER`` nested request header + ``ETHTOOL_A_MM_PMAC_ENABLED`` bool set if RX of preemptible and SMD-V + frames is enabled + ``ETHTOOL_A_MM_TX_ENABLED`` bool set if TX of preemptible frames is + administratively enabled (might be + inactive if verification failed) + ``ETHTOOL_A_MM_TX_ACTIVE`` bool set if TX of preemptible frames is + operationally enabled + ``ETHTOOL_A_MM_TX_MIN_FRAG_SIZE`` u32 minimum size of transmitted + non-final fragments, in octets + ``ETHTOOL_A_MM_RX_MIN_FRAG_SIZE`` u32 minimum size of received non-final + fragments, in octets + ``ETHTOOL_A_MM_VERIFY_ENABLED`` bool set if TX of SMD-V frames is + administratively enabled + ``ETHTOOL_A_MM_VERIFY_STATUS`` u8 state of the verification function + ``ETHTOOL_A_MM_VERIFY_TIME`` u32 delay between verification attempts + ``ETHTOOL_A_MM_MAX_VERIFY_TIME``` u32 maximum verification interval + supported by device + ``ETHTOOL_A_MM_STATS`` nested IEEE 802.3-2018 subclause 30.14.1 + oMACMergeEntity statistics counters + ================================= ====== =================================== + +The attributes are populated by the device driver through the following +structure: + +.. kernel-doc:: include/linux/ethtool.h + :identifiers: ethtool_mm_state + +The ``ETHTOOL_A_MM_VERIFY_STATUS`` will report one of the values from + +.. kernel-doc:: include/uapi/linux/ethtool.h + :identifiers: ethtool_mm_verify_status + +If ``ETHTOOL_A_MM_VERIFY_ENABLED`` was passed as false in the ``MM_SET`` +command, ``ETHTOOL_A_MM_VERIFY_STATUS`` will report either +``ETHTOOL_MM_VERIFY_STATUS_INITIAL`` or ``ETHTOOL_MM_VERIFY_STATUS_DISABLED``, +otherwise it should report one of the other states. + +It is recommended that drivers start with the pMAC disabled, and enable it upon +user space request. It is also recommended that user space does not depend upon +the default values from ``ETHTOOL_MSG_MM_GET`` requests. + +``ETHTOOL_A_MM_STATS`` are reported if ``ETHTOOL_FLAG_STATS`` was set in +``ETHTOOL_A_HEADER_FLAGS``. The attribute will be empty if driver did not +report any statistics. Drivers fill in the statistics in the following +structure: + +.. kernel-doc:: include/linux/ethtool.h + :identifiers: ethtool_mm_stats + +MM_SET +====== + +Modifies the configuration of the 802.3 MAC Merge layer. + +Request contents: + + ================================= ====== ========================== + ``ETHTOOL_A_MM_VERIFY_TIME`` u32 see MM_GET description + ``ETHTOOL_A_MM_VERIFY_ENABLED`` bool see MM_GET description + ``ETHTOOL_A_MM_TX_ENABLED`` bool see MM_GET description + ``ETHTOOL_A_MM_PMAC_ENABLED`` bool see MM_GET description + ``ETHTOOL_A_MM_TX_MIN_FRAG_SIZE`` u32 see MM_GET description + ================================= ====== ========================== + +The attributes are propagated to the driver through the following structure: + +.. kernel-doc:: include/linux/ethtool.h + :identifiers: ethtool_mm_cfg + +Request translation +=================== + +The following table maps ioctl commands to netlink commands providing their +functionality. Entries with "n/a" in right column are commands which do not +have their netlink replacement yet. Entries which "n/a" in the left column +are netlink only. + + =================================== ===================================== + ioctl command netlink command + =================================== ===================================== + ``ETHTOOL_GSET`` ``ETHTOOL_MSG_LINKINFO_GET`` + ``ETHTOOL_MSG_LINKMODES_GET`` + ``ETHTOOL_SSET`` ``ETHTOOL_MSG_LINKINFO_SET`` + ``ETHTOOL_MSG_LINKMODES_SET`` + ``ETHTOOL_GDRVINFO`` n/a + ``ETHTOOL_GREGS`` n/a + ``ETHTOOL_GWOL`` ``ETHTOOL_MSG_WOL_GET`` + ``ETHTOOL_SWOL`` ``ETHTOOL_MSG_WOL_SET`` + ``ETHTOOL_GMSGLVL`` ``ETHTOOL_MSG_DEBUG_GET`` + ``ETHTOOL_SMSGLVL`` ``ETHTOOL_MSG_DEBUG_SET`` + ``ETHTOOL_NWAY_RST`` n/a + ``ETHTOOL_GLINK`` ``ETHTOOL_MSG_LINKSTATE_GET`` + ``ETHTOOL_GEEPROM`` n/a + ``ETHTOOL_SEEPROM`` n/a + ``ETHTOOL_GCOALESCE`` ``ETHTOOL_MSG_COALESCE_GET`` + ``ETHTOOL_SCOALESCE`` ``ETHTOOL_MSG_COALESCE_SET`` + ``ETHTOOL_GRINGPARAM`` ``ETHTOOL_MSG_RINGS_GET`` + ``ETHTOOL_SRINGPARAM`` ``ETHTOOL_MSG_RINGS_SET`` + ``ETHTOOL_GPAUSEPARAM`` ``ETHTOOL_MSG_PAUSE_GET`` + ``ETHTOOL_SPAUSEPARAM`` ``ETHTOOL_MSG_PAUSE_SET`` + ``ETHTOOL_GRXCSUM`` ``ETHTOOL_MSG_FEATURES_GET`` + ``ETHTOOL_SRXCSUM`` ``ETHTOOL_MSG_FEATURES_SET`` + ``ETHTOOL_GTXCSUM`` ``ETHTOOL_MSG_FEATURES_GET`` + ``ETHTOOL_STXCSUM`` ``ETHTOOL_MSG_FEATURES_SET`` + ``ETHTOOL_GSG`` ``ETHTOOL_MSG_FEATURES_GET`` + ``ETHTOOL_SSG`` ``ETHTOOL_MSG_FEATURES_SET`` + ``ETHTOOL_TEST`` n/a + ``ETHTOOL_GSTRINGS`` ``ETHTOOL_MSG_STRSET_GET`` + ``ETHTOOL_PHYS_ID`` n/a + ``ETHTOOL_GSTATS`` n/a + ``ETHTOOL_GTSO`` ``ETHTOOL_MSG_FEATURES_GET`` + ``ETHTOOL_STSO`` ``ETHTOOL_MSG_FEATURES_SET`` + ``ETHTOOL_GPERMADDR`` rtnetlink ``RTM_GETLINK`` + ``ETHTOOL_GUFO`` ``ETHTOOL_MSG_FEATURES_GET`` + ``ETHTOOL_SUFO`` ``ETHTOOL_MSG_FEATURES_SET`` + ``ETHTOOL_GGSO`` ``ETHTOOL_MSG_FEATURES_GET`` + ``ETHTOOL_SGSO`` ``ETHTOOL_MSG_FEATURES_SET`` + ``ETHTOOL_GFLAGS`` ``ETHTOOL_MSG_FEATURES_GET`` + ``ETHTOOL_SFLAGS`` ``ETHTOOL_MSG_FEATURES_SET`` + ``ETHTOOL_GPFLAGS`` ``ETHTOOL_MSG_PRIVFLAGS_GET`` + ``ETHTOOL_SPFLAGS`` ``ETHTOOL_MSG_PRIVFLAGS_SET`` + ``ETHTOOL_GRXFH`` n/a + ``ETHTOOL_SRXFH`` n/a + ``ETHTOOL_GGRO`` ``ETHTOOL_MSG_FEATURES_GET`` + ``ETHTOOL_SGRO`` ``ETHTOOL_MSG_FEATURES_SET`` + ``ETHTOOL_GRXRINGS`` n/a + ``ETHTOOL_GRXCLSRLCNT`` n/a + ``ETHTOOL_GRXCLSRULE`` n/a + ``ETHTOOL_GRXCLSRLALL`` n/a + ``ETHTOOL_SRXCLSRLDEL`` n/a + ``ETHTOOL_SRXCLSRLINS`` n/a + ``ETHTOOL_FLASHDEV`` n/a + ``ETHTOOL_RESET`` n/a + ``ETHTOOL_SRXNTUPLE`` n/a + ``ETHTOOL_GRXNTUPLE`` n/a + ``ETHTOOL_GSSET_INFO`` ``ETHTOOL_MSG_STRSET_GET`` + ``ETHTOOL_GRXFHINDIR`` n/a + ``ETHTOOL_SRXFHINDIR`` n/a + ``ETHTOOL_GFEATURES`` ``ETHTOOL_MSG_FEATURES_GET`` + ``ETHTOOL_SFEATURES`` ``ETHTOOL_MSG_FEATURES_SET`` + ``ETHTOOL_GCHANNELS`` ``ETHTOOL_MSG_CHANNELS_GET`` + ``ETHTOOL_SCHANNELS`` ``ETHTOOL_MSG_CHANNELS_SET`` + ``ETHTOOL_SET_DUMP`` n/a + ``ETHTOOL_GET_DUMP_FLAG`` n/a + ``ETHTOOL_GET_DUMP_DATA`` n/a + ``ETHTOOL_GET_TS_INFO`` ``ETHTOOL_MSG_TSINFO_GET`` + ``ETHTOOL_GMODULEINFO`` ``ETHTOOL_MSG_MODULE_EEPROM_GET`` + ``ETHTOOL_GMODULEEEPROM`` ``ETHTOOL_MSG_MODULE_EEPROM_GET`` + ``ETHTOOL_GEEE`` ``ETHTOOL_MSG_EEE_GET`` + ``ETHTOOL_SEEE`` ``ETHTOOL_MSG_EEE_SET`` + ``ETHTOOL_GRSSH`` ``ETHTOOL_MSG_RSS_GET`` + ``ETHTOOL_SRSSH`` n/a + ``ETHTOOL_GTUNABLE`` n/a + ``ETHTOOL_STUNABLE`` n/a + ``ETHTOOL_GPHYSTATS`` n/a + ``ETHTOOL_PERQUEUE`` n/a + ``ETHTOOL_GLINKSETTINGS`` ``ETHTOOL_MSG_LINKINFO_GET`` + ``ETHTOOL_MSG_LINKMODES_GET`` + ``ETHTOOL_SLINKSETTINGS`` ``ETHTOOL_MSG_LINKINFO_SET`` + ``ETHTOOL_MSG_LINKMODES_SET`` + ``ETHTOOL_PHY_GTUNABLE`` n/a + ``ETHTOOL_PHY_STUNABLE`` n/a + ``ETHTOOL_GFECPARAM`` ``ETHTOOL_MSG_FEC_GET`` + ``ETHTOOL_SFECPARAM`` ``ETHTOOL_MSG_FEC_SET`` + n/a ``ETHTOOL_MSG_CABLE_TEST_ACT`` + n/a ``ETHTOOL_MSG_CABLE_TEST_TDR_ACT`` + n/a ``ETHTOOL_MSG_TUNNEL_INFO_GET`` + n/a ``ETHTOOL_MSG_PHC_VCLOCKS_GET`` + n/a ``ETHTOOL_MSG_MODULE_GET`` + n/a ``ETHTOOL_MSG_MODULE_SET`` + n/a ``ETHTOOL_MSG_PLCA_GET_CFG`` + n/a ``ETHTOOL_MSG_PLCA_SET_CFG`` + n/a ``ETHTOOL_MSG_PLCA_GET_STATUS`` + n/a ``ETHTOOL_MSG_MM_GET`` + n/a ``ETHTOOL_MSG_MM_SET`` + =================================== ===================================== diff --git a/Documentation/networking/failover.rst b/Documentation/networking/failover.rst new file mode 100644 index 0000000000..f0c8483cdb --- /dev/null +++ b/Documentation/networking/failover.rst @@ -0,0 +1,18 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======== +FAILOVER +======== + +Overview +======== + +The failover module provides a generic interface for paravirtual drivers +to register a netdev and a set of ops with a failover instance. The ops +are used as event handlers that get called to handle netdev register/ +unregister/link change/name change events on slave pci ethernet devices +with the same mac address as the failover netdev. + +This enables paravirtual drivers to use a VF as an accelerated low latency +datapath. It also allows live migration of VMs with direct attached VFs by +failing over to the paravirtual datapath when the VF is unplugged. diff --git a/Documentation/networking/fib_trie.rst b/Documentation/networking/fib_trie.rst new file mode 100644 index 0000000000..f1435b7fcd --- /dev/null +++ b/Documentation/networking/fib_trie.rst @@ -0,0 +1,149 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================ +LC-trie implementation notes +============================ + +Node types +---------- +leaf + An end node with data. This has a copy of the relevant key, along + with 'hlist' with routing table entries sorted by prefix length. + See struct leaf and struct leaf_info. + +trie node or tnode + An internal node, holding an array of child (leaf or tnode) pointers, + indexed through a subset of the key. See Level Compression. + +A few concepts explained +------------------------ +Bits (tnode) + The number of bits in the key segment used for indexing into the + child array - the "child index". See Level Compression. + +Pos (tnode) + The position (in the key) of the key segment used for indexing into + the child array. See Path Compression. + +Path Compression / skipped bits + Any given tnode is linked to from the child array of its parent, using + a segment of the key specified by the parent's "pos" and "bits" + In certain cases, this tnode's own "pos" will not be immediately + adjacent to the parent (pos+bits), but there will be some bits + in the key skipped over because they represent a single path with no + deviations. These "skipped bits" constitute Path Compression. + Note that the search algorithm will simply skip over these bits when + searching, making it necessary to save the keys in the leaves to + verify that they actually do match the key we are searching for. + +Level Compression / child arrays + the trie is kept level balanced moving, under certain conditions, the + children of a full child (see "full_children") up one level, so that + instead of a pure binary tree, each internal node ("tnode") may + contain an arbitrarily large array of links to several children. + Conversely, a tnode with a mostly empty child array (see empty_children) + may be "halved", having some of its children moved downwards one level, + in order to avoid ever-increasing child arrays. + +empty_children + the number of positions in the child array of a given tnode that are + NULL. + +full_children + the number of children of a given tnode that aren't path compressed. + (in other words, they aren't NULL or leaves and their "pos" is equal + to this tnode's "pos"+"bits"). + + (The word "full" here is used more in the sense of "complete" than + as the opposite of "empty", which might be a tad confusing.) + +Comments +--------- + +We have tried to keep the structure of the code as close to fib_hash as +possible to allow verification and help up reviewing. + +fib_find_node() + A good start for understanding this code. This function implements a + straightforward trie lookup. + +fib_insert_node() + Inserts a new leaf node in the trie. This is bit more complicated than + fib_find_node(). Inserting a new node means we might have to run the + level compression algorithm on part of the trie. + +trie_leaf_remove() + Looks up a key, deletes it and runs the level compression algorithm. + +trie_rebalance() + The key function for the dynamic trie after any change in the trie + it is run to optimize and reorganize. It will walk the trie upwards + towards the root from a given tnode, doing a resize() at each step + to implement level compression. + +resize() + Analyzes a tnode and optimizes the child array size by either inflating + or shrinking it repeatedly until it fulfills the criteria for optimal + level compression. This part follows the original paper pretty closely + and there may be some room for experimentation here. + +inflate() + Doubles the size of the child array within a tnode. Used by resize(). + +halve() + Halves the size of the child array within a tnode - the inverse of + inflate(). Used by resize(); + +fn_trie_insert(), fn_trie_delete(), fn_trie_select_default() + The route manipulation functions. Should conform pretty closely to the + corresponding functions in fib_hash. + +fn_trie_flush() + This walks the full trie (using nextleaf()) and searches for empty + leaves which have to be removed. + +fn_trie_dump() + Dumps the routing table ordered by prefix length. This is somewhat + slower than the corresponding fib_hash function, as we have to walk the + entire trie for each prefix length. In comparison, fib_hash is organized + as one "zone"/hash per prefix length. + +Locking +------- + +fib_lock is used for an RW-lock in the same way that this is done in fib_hash. +However, the functions are somewhat separated for other possible locking +scenarios. It might conceivably be possible to run trie_rebalance via RCU +to avoid read_lock in the fn_trie_lookup() function. + +Main lookup mechanism +--------------------- +fn_trie_lookup() is the main lookup function. + +The lookup is in its simplest form just like fib_find_node(). We descend the +trie, key segment by key segment, until we find a leaf. check_leaf() does +the fib_semantic_match in the leaf's sorted prefix hlist. + +If we find a match, we are done. + +If we don't find a match, we enter prefix matching mode. The prefix length, +starting out at the same as the key length, is reduced one step at a time, +and we backtrack upwards through the trie trying to find a longest matching +prefix. The goal is always to reach a leaf and get a positive result from the +fib_semantic_match mechanism. + +Inside each tnode, the search for longest matching prefix consists of searching +through the child array, chopping off (zeroing) the least significant "1" of +the child index until we find a match or the child index consists of nothing but +zeros. + +At this point we backtrack (t->stats.backtrack++) up the trie, continuing to +chop off part of the key in order to find the longest matching prefix. + +At this point we will repeatedly descend subtries to look for a match, and there +are some optimizations available that can provide us with "shortcuts" to avoid +descending into dead ends. Look for "HL_OPTIMIZE" sections in the code. + +To alleviate any doubts about the correctness of the route selection process, +a new netlink operation has been added. Look for NETLINK_FIB_LOOKUP, which +gives userland access to fib_lookup(). diff --git a/Documentation/networking/filter.rst b/Documentation/networking/filter.rst new file mode 100644 index 0000000000..f69da50748 --- /dev/null +++ b/Documentation/networking/filter.rst @@ -0,0 +1,685 @@ +.. SPDX-License-Identifier: GPL-2.0 + +.. _networking-filter: + +======================================================= +Linux Socket Filtering aka Berkeley Packet Filter (BPF) +======================================================= + +Notice +------ + +This file used to document the eBPF format and mechanisms even when not +related to socket filtering. The ../bpf/index.rst has more details +on eBPF. + +Introduction +------------ + +Linux Socket Filtering (LSF) is derived from the Berkeley Packet Filter. +Though there are some distinct differences between the BSD and Linux +Kernel filtering, but when we speak of BPF or LSF in Linux context, we +mean the very same mechanism of filtering in the Linux kernel. + +BPF allows a user-space program to attach a filter onto any socket and +allow or disallow certain types of data to come through the socket. LSF +follows exactly the same filter code structure as BSD's BPF, so referring +to the BSD bpf.4 manpage is very helpful in creating filters. + +On Linux, BPF is much simpler than on BSD. One does not have to worry +about devices or anything like that. You simply create your filter code, +send it to the kernel via the SO_ATTACH_FILTER option and if your filter +code passes the kernel check on it, you then immediately begin filtering +data on that socket. + +You can also detach filters from your socket via the SO_DETACH_FILTER +option. This will probably not be used much since when you close a socket +that has a filter on it the filter is automagically removed. The other +less common case may be adding a different filter on the same socket where +you had another filter that is still running: the kernel takes care of +removing the old one and placing your new one in its place, assuming your +filter has passed the checks, otherwise if it fails the old filter will +remain on that socket. + +SO_LOCK_FILTER option allows to lock the filter attached to a socket. Once +set, a filter cannot be removed or changed. This allows one process to +setup a socket, attach a filter, lock it then drop privileges and be +assured that the filter will be kept until the socket is closed. + +The biggest user of this construct might be libpcap. Issuing a high-level +filter command like `tcpdump -i em1 port 22` passes through the libpcap +internal compiler that generates a structure that can eventually be loaded +via SO_ATTACH_FILTER to the kernel. `tcpdump -i em1 port 22 -ddd` +displays what is being placed into this structure. + +Although we were only speaking about sockets here, BPF in Linux is used +in many more places. There's xt_bpf for netfilter, cls_bpf in the kernel +qdisc layer, SECCOMP-BPF (SECure COMPuting [1]_), and lots of other places +such as team driver, PTP code, etc where BPF is being used. + +.. [1] Documentation/userspace-api/seccomp_filter.rst + +Original BPF paper: + +Steven McCanne and Van Jacobson. 1993. The BSD packet filter: a new +architecture for user-level packet capture. In Proceedings of the +USENIX Winter 1993 Conference Proceedings on USENIX Winter 1993 +Conference Proceedings (USENIX'93). USENIX Association, Berkeley, +CA, USA, 2-2. [http://www.tcpdump.org/papers/bpf-usenix93.pdf] + +Structure +--------- + +User space applications include <linux/filter.h> which contains the +following relevant structures:: + + struct sock_filter { /* Filter block */ + __u16 code; /* Actual filter code */ + __u8 jt; /* Jump true */ + __u8 jf; /* Jump false */ + __u32 k; /* Generic multiuse field */ + }; + +Such a structure is assembled as an array of 4-tuples, that contains +a code, jt, jf and k value. jt and jf are jump offsets and k a generic +value to be used for a provided code:: + + struct sock_fprog { /* Required for SO_ATTACH_FILTER. */ + unsigned short len; /* Number of filter blocks */ + struct sock_filter __user *filter; + }; + +For socket filtering, a pointer to this structure (as shown in +follow-up example) is being passed to the kernel through setsockopt(2). + +Example +------- + +:: + + #include <sys/socket.h> + #include <sys/types.h> + #include <arpa/inet.h> + #include <linux/if_ether.h> + /* ... */ + + /* From the example above: tcpdump -i em1 port 22 -dd */ + struct sock_filter code[] = { + { 0x28, 0, 0, 0x0000000c }, + { 0x15, 0, 8, 0x000086dd }, + { 0x30, 0, 0, 0x00000014 }, + { 0x15, 2, 0, 0x00000084 }, + { 0x15, 1, 0, 0x00000006 }, + { 0x15, 0, 17, 0x00000011 }, + { 0x28, 0, 0, 0x00000036 }, + { 0x15, 14, 0, 0x00000016 }, + { 0x28, 0, 0, 0x00000038 }, + { 0x15, 12, 13, 0x00000016 }, + { 0x15, 0, 12, 0x00000800 }, + { 0x30, 0, 0, 0x00000017 }, + { 0x15, 2, 0, 0x00000084 }, + { 0x15, 1, 0, 0x00000006 }, + { 0x15, 0, 8, 0x00000011 }, + { 0x28, 0, 0, 0x00000014 }, + { 0x45, 6, 0, 0x00001fff }, + { 0xb1, 0, 0, 0x0000000e }, + { 0x48, 0, 0, 0x0000000e }, + { 0x15, 2, 0, 0x00000016 }, + { 0x48, 0, 0, 0x00000010 }, + { 0x15, 0, 1, 0x00000016 }, + { 0x06, 0, 0, 0x0000ffff }, + { 0x06, 0, 0, 0x00000000 }, + }; + + struct sock_fprog bpf = { + .len = ARRAY_SIZE(code), + .filter = code, + }; + + sock = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL)); + if (sock < 0) + /* ... bail out ... */ + + ret = setsockopt(sock, SOL_SOCKET, SO_ATTACH_FILTER, &bpf, sizeof(bpf)); + if (ret < 0) + /* ... bail out ... */ + + /* ... */ + close(sock); + +The above example code attaches a socket filter for a PF_PACKET socket +in order to let all IPv4/IPv6 packets with port 22 pass. The rest will +be dropped for this socket. + +The setsockopt(2) call to SO_DETACH_FILTER doesn't need any arguments +and SO_LOCK_FILTER for preventing the filter to be detached, takes an +integer value with 0 or 1. + +Note that socket filters are not restricted to PF_PACKET sockets only, +but can also be used on other socket families. + +Summary of system calls: + + * setsockopt(sockfd, SOL_SOCKET, SO_ATTACH_FILTER, &val, sizeof(val)); + * setsockopt(sockfd, SOL_SOCKET, SO_DETACH_FILTER, &val, sizeof(val)); + * setsockopt(sockfd, SOL_SOCKET, SO_LOCK_FILTER, &val, sizeof(val)); + +Normally, most use cases for socket filtering on packet sockets will be +covered by libpcap in high-level syntax, so as an application developer +you should stick to that. libpcap wraps its own layer around all that. + +Unless i) using/linking to libpcap is not an option, ii) the required BPF +filters use Linux extensions that are not supported by libpcap's compiler, +iii) a filter might be more complex and not cleanly implementable with +libpcap's compiler, or iv) particular filter codes should be optimized +differently than libpcap's internal compiler does; then in such cases +writing such a filter "by hand" can be of an alternative. For example, +xt_bpf and cls_bpf users might have requirements that could result in +more complex filter code, or one that cannot be expressed with libpcap +(e.g. different return codes for various code paths). Moreover, BPF JIT +implementors may wish to manually write test cases and thus need low-level +access to BPF code as well. + +BPF engine and instruction set +------------------------------ + +Under tools/bpf/ there's a small helper tool called bpf_asm which can +be used to write low-level filters for example scenarios mentioned in the +previous section. Asm-like syntax mentioned here has been implemented in +bpf_asm and will be used for further explanations (instead of dealing with +less readable opcodes directly, principles are the same). The syntax is +closely modelled after Steven McCanne's and Van Jacobson's BPF paper. + +The BPF architecture consists of the following basic elements: + + ======= ==================================================== + Element Description + ======= ==================================================== + A 32 bit wide accumulator + X 32 bit wide X register + M[] 16 x 32 bit wide misc registers aka "scratch memory + store", addressable from 0 to 15 + ======= ==================================================== + +A program, that is translated by bpf_asm into "opcodes" is an array that +consists of the following elements (as already mentioned):: + + op:16, jt:8, jf:8, k:32 + +The element op is a 16 bit wide opcode that has a particular instruction +encoded. jt and jf are two 8 bit wide jump targets, one for condition +"jump if true", the other one "jump if false". Eventually, element k +contains a miscellaneous argument that can be interpreted in different +ways depending on the given instruction in op. + +The instruction set consists of load, store, branch, alu, miscellaneous +and return instructions that are also represented in bpf_asm syntax. This +table lists all bpf_asm instructions available resp. what their underlying +opcodes as defined in linux/filter.h stand for: + + =========== =================== ===================== + Instruction Addressing mode Description + =========== =================== ===================== + ld 1, 2, 3, 4, 12 Load word into A + ldi 4 Load word into A + ldh 1, 2 Load half-word into A + ldb 1, 2 Load byte into A + ldx 3, 4, 5, 12 Load word into X + ldxi 4 Load word into X + ldxb 5 Load byte into X + + st 3 Store A into M[] + stx 3 Store X into M[] + + jmp 6 Jump to label + ja 6 Jump to label + jeq 7, 8, 9, 10 Jump on A == <x> + jneq 9, 10 Jump on A != <x> + jne 9, 10 Jump on A != <x> + jlt 9, 10 Jump on A < <x> + jle 9, 10 Jump on A <= <x> + jgt 7, 8, 9, 10 Jump on A > <x> + jge 7, 8, 9, 10 Jump on A >= <x> + jset 7, 8, 9, 10 Jump on A & <x> + + add 0, 4 A + <x> + sub 0, 4 A - <x> + mul 0, 4 A * <x> + div 0, 4 A / <x> + mod 0, 4 A % <x> + neg !A + and 0, 4 A & <x> + or 0, 4 A | <x> + xor 0, 4 A ^ <x> + lsh 0, 4 A << <x> + rsh 0, 4 A >> <x> + + tax Copy A into X + txa Copy X into A + + ret 4, 11 Return + =========== =================== ===================== + +The next table shows addressing formats from the 2nd column: + + =============== =================== =============================================== + Addressing mode Syntax Description + =============== =================== =============================================== + 0 x/%x Register X + 1 [k] BHW at byte offset k in the packet + 2 [x + k] BHW at the offset X + k in the packet + 3 M[k] Word at offset k in M[] + 4 #k Literal value stored in k + 5 4*([k]&0xf) Lower nibble * 4 at byte offset k in the packet + 6 L Jump label L + 7 #k,Lt,Lf Jump to Lt if true, otherwise jump to Lf + 8 x/%x,Lt,Lf Jump to Lt if true, otherwise jump to Lf + 9 #k,Lt Jump to Lt if predicate is true + 10 x/%x,Lt Jump to Lt if predicate is true + 11 a/%a Accumulator A + 12 extension BPF extension + =============== =================== =============================================== + +The Linux kernel also has a couple of BPF extensions that are used along +with the class of load instructions by "overloading" the k argument with +a negative offset + a particular extension offset. The result of such BPF +extensions are loaded into A. + +Possible BPF extensions are shown in the following table: + + =================================== ================================================= + Extension Description + =================================== ================================================= + len skb->len + proto skb->protocol + type skb->pkt_type + poff Payload start offset + ifidx skb->dev->ifindex + nla Netlink attribute of type X with offset A + nlan Nested Netlink attribute of type X with offset A + mark skb->mark + queue skb->queue_mapping + hatype skb->dev->type + rxhash skb->hash + cpu raw_smp_processor_id() + vlan_tci skb_vlan_tag_get(skb) + vlan_avail skb_vlan_tag_present(skb) + vlan_tpid skb->vlan_proto + rand get_random_u32() + =================================== ================================================= + +These extensions can also be prefixed with '#'. +Examples for low-level BPF: + +**ARP packets**:: + + ldh [12] + jne #0x806, drop + ret #-1 + drop: ret #0 + +**IPv4 TCP packets**:: + + ldh [12] + jne #0x800, drop + ldb [23] + jneq #6, drop + ret #-1 + drop: ret #0 + +**icmp random packet sampling, 1 in 4**:: + + ldh [12] + jne #0x800, drop + ldb [23] + jneq #1, drop + # get a random uint32 number + ld rand + mod #4 + jneq #1, drop + ret #-1 + drop: ret #0 + +**SECCOMP filter example**:: + + ld [4] /* offsetof(struct seccomp_data, arch) */ + jne #0xc000003e, bad /* AUDIT_ARCH_X86_64 */ + ld [0] /* offsetof(struct seccomp_data, nr) */ + jeq #15, good /* __NR_rt_sigreturn */ + jeq #231, good /* __NR_exit_group */ + jeq #60, good /* __NR_exit */ + jeq #0, good /* __NR_read */ + jeq #1, good /* __NR_write */ + jeq #5, good /* __NR_fstat */ + jeq #9, good /* __NR_mmap */ + jeq #14, good /* __NR_rt_sigprocmask */ + jeq #13, good /* __NR_rt_sigaction */ + jeq #35, good /* __NR_nanosleep */ + bad: ret #0 /* SECCOMP_RET_KILL_THREAD */ + good: ret #0x7fff0000 /* SECCOMP_RET_ALLOW */ + +Examples for low-level BPF extension: + +**Packet for interface index 13**:: + + ld ifidx + jneq #13, drop + ret #-1 + drop: ret #0 + +**(Accelerated) VLAN w/ id 10**:: + + ld vlan_tci + jneq #10, drop + ret #-1 + drop: ret #0 + +The above example code can be placed into a file (here called "foo"), and +then be passed to the bpf_asm tool for generating opcodes, output that xt_bpf +and cls_bpf understands and can directly be loaded with. Example with above +ARP code:: + + $ ./bpf_asm foo + 4,40 0 0 12,21 0 1 2054,6 0 0 4294967295,6 0 0 0, + +In copy and paste C-like output:: + + $ ./bpf_asm -c foo + { 0x28, 0, 0, 0x0000000c }, + { 0x15, 0, 1, 0x00000806 }, + { 0x06, 0, 0, 0xffffffff }, + { 0x06, 0, 0, 0000000000 }, + +In particular, as usage with xt_bpf or cls_bpf can result in more complex BPF +filters that might not be obvious at first, it's good to test filters before +attaching to a live system. For that purpose, there's a small tool called +bpf_dbg under tools/bpf/ in the kernel source directory. This debugger allows +for testing BPF filters against given pcap files, single stepping through the +BPF code on the pcap's packets and to do BPF machine register dumps. + +Starting bpf_dbg is trivial and just requires issuing:: + + # ./bpf_dbg + +In case input and output do not equal stdin/stdout, bpf_dbg takes an +alternative stdin source as a first argument, and an alternative stdout +sink as a second one, e.g. `./bpf_dbg test_in.txt test_out.txt`. + +Other than that, a particular libreadline configuration can be set via +file "~/.bpf_dbg_init" and the command history is stored in the file +"~/.bpf_dbg_history". + +Interaction in bpf_dbg happens through a shell that also has auto-completion +support (follow-up example commands starting with '>' denote bpf_dbg shell). +The usual workflow would be to ... + +* load bpf 6,40 0 0 12,21 0 3 2048,48 0 0 23,21 0 1 1,6 0 0 65535,6 0 0 0 + Loads a BPF filter from standard output of bpf_asm, or transformed via + e.g. ``tcpdump -iem1 -ddd port 22 | tr '\n' ','``. Note that for JIT + debugging (next section), this command creates a temporary socket and + loads the BPF code into the kernel. Thus, this will also be useful for + JIT developers. + +* load pcap foo.pcap + + Loads standard tcpdump pcap file. + +* run [<n>] + +bpf passes:1 fails:9 + Runs through all packets from a pcap to account how many passes and fails + the filter will generate. A limit of packets to traverse can be given. + +* disassemble:: + + l0: ldh [12] + l1: jeq #0x800, l2, l5 + l2: ldb [23] + l3: jeq #0x1, l4, l5 + l4: ret #0xffff + l5: ret #0 + + Prints out BPF code disassembly. + +* dump:: + + /* { op, jt, jf, k }, */ + { 0x28, 0, 0, 0x0000000c }, + { 0x15, 0, 3, 0x00000800 }, + { 0x30, 0, 0, 0x00000017 }, + { 0x15, 0, 1, 0x00000001 }, + { 0x06, 0, 0, 0x0000ffff }, + { 0x06, 0, 0, 0000000000 }, + + Prints out C-style BPF code dump. + +* breakpoint 0:: + + breakpoint at: l0: ldh [12] + +* breakpoint 1:: + + breakpoint at: l1: jeq #0x800, l2, l5 + + ... + + Sets breakpoints at particular BPF instructions. Issuing a `run` command + will walk through the pcap file continuing from the current packet and + break when a breakpoint is being hit (another `run` will continue from + the currently active breakpoint executing next instructions): + + * run:: + + -- register dump -- + pc: [0] <-- program counter + code: [40] jt[0] jf[0] k[12] <-- plain BPF code of current instruction + curr: l0: ldh [12] <-- disassembly of current instruction + A: [00000000][0] <-- content of A (hex, decimal) + X: [00000000][0] <-- content of X (hex, decimal) + M[0,15]: [00000000][0] <-- folded content of M (hex, decimal) + -- packet dump -- <-- Current packet from pcap (hex) + len: 42 + 0: 00 19 cb 55 55 a4 00 14 a4 43 78 69 08 06 00 01 + 16: 08 00 06 04 00 01 00 14 a4 43 78 69 0a 3b 01 26 + 32: 00 00 00 00 00 00 0a 3b 01 01 + (breakpoint) + > + + * breakpoint:: + + breakpoints: 0 1 + + Prints currently set breakpoints. + +* step [-<n>, +<n>] + + Performs single stepping through the BPF program from the current pc + offset. Thus, on each step invocation, above register dump is issued. + This can go forwards and backwards in time, a plain `step` will break + on the next BPF instruction, thus +1. (No `run` needs to be issued here.) + +* select <n> + + Selects a given packet from the pcap file to continue from. Thus, on + the next `run` or `step`, the BPF program is being evaluated against + the user pre-selected packet. Numbering starts just as in Wireshark + with index 1. + +* quit + + Exits bpf_dbg. + +JIT compiler +------------ + +The Linux kernel has a built-in BPF JIT compiler for x86_64, SPARC, +PowerPC, ARM, ARM64, MIPS, RISC-V and s390 and can be enabled through +CONFIG_BPF_JIT. The JIT compiler is transparently invoked for each +attached filter from user space or for internal kernel users if it has +been previously enabled by root:: + + echo 1 > /proc/sys/net/core/bpf_jit_enable + +For JIT developers, doing audits etc, each compile run can output the generated +opcode image into the kernel log via:: + + echo 2 > /proc/sys/net/core/bpf_jit_enable + +Example output from dmesg:: + + [ 3389.935842] flen=6 proglen=70 pass=3 image=ffffffffa0069c8f + [ 3389.935847] JIT code: 00000000: 55 48 89 e5 48 83 ec 60 48 89 5d f8 44 8b 4f 68 + [ 3389.935849] JIT code: 00000010: 44 2b 4f 6c 4c 8b 87 d8 00 00 00 be 0c 00 00 00 + [ 3389.935850] JIT code: 00000020: e8 1d 94 ff e0 3d 00 08 00 00 75 16 be 17 00 00 + [ 3389.935851] JIT code: 00000030: 00 e8 28 94 ff e0 83 f8 01 75 07 b8 ff ff 00 00 + [ 3389.935852] JIT code: 00000040: eb 02 31 c0 c9 c3 + +When CONFIG_BPF_JIT_ALWAYS_ON is enabled, bpf_jit_enable is permanently set to 1 and +setting any other value than that will return in failure. This is even the case for +setting bpf_jit_enable to 2, since dumping the final JIT image into the kernel log +is discouraged and introspection through bpftool (under tools/bpf/bpftool/) is the +generally recommended approach instead. + +In the kernel source tree under tools/bpf/, there's bpf_jit_disasm for +generating disassembly out of the kernel log's hexdump:: + + # ./bpf_jit_disasm + 70 bytes emitted from JIT compiler (pass:3, flen:6) + ffffffffa0069c8f + <x>: + 0: push %rbp + 1: mov %rsp,%rbp + 4: sub $0x60,%rsp + 8: mov %rbx,-0x8(%rbp) + c: mov 0x68(%rdi),%r9d + 10: sub 0x6c(%rdi),%r9d + 14: mov 0xd8(%rdi),%r8 + 1b: mov $0xc,%esi + 20: callq 0xffffffffe0ff9442 + 25: cmp $0x800,%eax + 2a: jne 0x0000000000000042 + 2c: mov $0x17,%esi + 31: callq 0xffffffffe0ff945e + 36: cmp $0x1,%eax + 39: jne 0x0000000000000042 + 3b: mov $0xffff,%eax + 40: jmp 0x0000000000000044 + 42: xor %eax,%eax + 44: leaveq + 45: retq + + Issuing option `-o` will "annotate" opcodes to resulting assembler + instructions, which can be very useful for JIT developers: + + # ./bpf_jit_disasm -o + 70 bytes emitted from JIT compiler (pass:3, flen:6) + ffffffffa0069c8f + <x>: + 0: push %rbp + 55 + 1: mov %rsp,%rbp + 48 89 e5 + 4: sub $0x60,%rsp + 48 83 ec 60 + 8: mov %rbx,-0x8(%rbp) + 48 89 5d f8 + c: mov 0x68(%rdi),%r9d + 44 8b 4f 68 + 10: sub 0x6c(%rdi),%r9d + 44 2b 4f 6c + 14: mov 0xd8(%rdi),%r8 + 4c 8b 87 d8 00 00 00 + 1b: mov $0xc,%esi + be 0c 00 00 00 + 20: callq 0xffffffffe0ff9442 + e8 1d 94 ff e0 + 25: cmp $0x800,%eax + 3d 00 08 00 00 + 2a: jne 0x0000000000000042 + 75 16 + 2c: mov $0x17,%esi + be 17 00 00 00 + 31: callq 0xffffffffe0ff945e + e8 28 94 ff e0 + 36: cmp $0x1,%eax + 83 f8 01 + 39: jne 0x0000000000000042 + 75 07 + 3b: mov $0xffff,%eax + b8 ff ff 00 00 + 40: jmp 0x0000000000000044 + eb 02 + 42: xor %eax,%eax + 31 c0 + 44: leaveq + c9 + 45: retq + c3 + +For BPF JIT developers, bpf_jit_disasm, bpf_asm and bpf_dbg provides a useful +toolchain for developing and testing the kernel's JIT compiler. + +BPF kernel internals +-------------------- +Internally, for the kernel interpreter, a different instruction set +format with similar underlying principles from BPF described in previous +paragraphs is being used. However, the instruction set format is modelled +closer to the underlying architecture to mimic native instruction sets, so +that a better performance can be achieved (more details later). This new +ISA is called eBPF. See the ../bpf/index.rst for details. (Note: eBPF which +originates from [e]xtended BPF is not the same as BPF extensions! While +eBPF is an ISA, BPF extensions date back to classic BPF's 'overloading' +of BPF_LD | BPF_{B,H,W} | BPF_ABS instruction.) + +The new instruction set was originally designed with the possible goal in +mind to write programs in "restricted C" and compile into eBPF with a optional +GCC/LLVM backend, so that it can just-in-time map to modern 64-bit CPUs with +minimal performance overhead over two steps, that is, C -> eBPF -> native code. + +Currently, the new format is being used for running user BPF programs, which +includes seccomp BPF, classic socket filters, cls_bpf traffic classifier, +team driver's classifier for its load-balancing mode, netfilter's xt_bpf +extension, PTP dissector/classifier, and much more. They are all internally +converted by the kernel into the new instruction set representation and run +in the eBPF interpreter. For in-kernel handlers, this all works transparently +by using bpf_prog_create() for setting up the filter, resp. +bpf_prog_destroy() for destroying it. The function +bpf_prog_run(filter, ctx) transparently invokes eBPF interpreter or JITed +code to run the filter. 'filter' is a pointer to struct bpf_prog that we +got from bpf_prog_create(), and 'ctx' the given context (e.g. +skb pointer). All constraints and restrictions from bpf_check_classic() apply +before a conversion to the new layout is being done behind the scenes! + +Currently, the classic BPF format is being used for JITing on most +32-bit architectures, whereas x86-64, aarch64, s390x, powerpc64, +sparc64, arm32, riscv64, riscv32 perform JIT compilation from eBPF +instruction set. + +Testing +------- + +Next to the BPF toolchain, the kernel also ships a test module that contains +various test cases for classic and eBPF that can be executed against +the BPF interpreter and JIT compiler. It can be found in lib/test_bpf.c and +enabled via Kconfig:: + + CONFIG_TEST_BPF=m + +After the module has been built and installed, the test suite can be executed +via insmod or modprobe against 'test_bpf' module. Results of the test cases +including timings in nsec can be found in the kernel log (dmesg). + +Misc +---- + +Also trinity, the Linux syscall fuzzer, has built-in support for BPF and +SECCOMP-BPF kernel fuzzing. + +Written by +---------- + +The document was written in the hope that it is found useful and in order +to give potential BPF hackers or security auditors a better overview of +the underlying architecture. + +- Jay Schulist <jschlst@samba.org> +- Daniel Borkmann <daniel@iogearbox.net> +- Alexei Starovoitov <ast@kernel.org> diff --git a/Documentation/networking/gen_stats.rst b/Documentation/networking/gen_stats.rst new file mode 100644 index 0000000000..595a83b9a6 --- /dev/null +++ b/Documentation/networking/gen_stats.rst @@ -0,0 +1,129 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=============================================== +Generic networking statistics for netlink users +=============================================== + +Statistic counters are grouped into structs: + +==================== ===================== ===================== +Struct TLV type Description +==================== ===================== ===================== +gnet_stats_basic TCA_STATS_BASIC Basic statistics +gnet_stats_rate_est TCA_STATS_RATE_EST Rate estimator +gnet_stats_queue TCA_STATS_QUEUE Queue statistics +none TCA_STATS_APP Application specific +==================== ===================== ===================== + + +Collecting: +----------- + +Declare the statistic structs you need:: + + struct mystruct { + struct gnet_stats_basic bstats; + struct gnet_stats_queue qstats; + ... + }; + +Update statistics, in dequeue() methods only, (while owning qdisc->running):: + + mystruct->tstats.packet++; + mystruct->qstats.backlog += skb->pkt_len; + + +Export to userspace (Dump): +--------------------------- + +:: + + my_dumping_routine(struct sk_buff *skb, ...) + { + struct gnet_dump dump; + + if (gnet_stats_start_copy(skb, TCA_STATS2, &mystruct->lock, &dump, + TCA_PAD) < 0) + goto rtattr_failure; + + if (gnet_stats_copy_basic(&dump, &mystruct->bstats) < 0 || + gnet_stats_copy_queue(&dump, &mystruct->qstats) < 0 || + gnet_stats_copy_app(&dump, &xstats, sizeof(xstats)) < 0) + goto rtattr_failure; + + if (gnet_stats_finish_copy(&dump) < 0) + goto rtattr_failure; + ... + } + +TCA_STATS/TCA_XSTATS backward compatibility: +-------------------------------------------- + +Prior users of struct tc_stats and xstats can maintain backward +compatibility by calling the compat wrappers to keep providing the +existing TLV types:: + + my_dumping_routine(struct sk_buff *skb, ...) + { + if (gnet_stats_start_copy_compat(skb, TCA_STATS2, TCA_STATS, + TCA_XSTATS, &mystruct->lock, &dump, + TCA_PAD) < 0) + goto rtattr_failure; + ... + } + +A struct tc_stats will be filled out during gnet_stats_copy_* calls +and appended to the skb. TCA_XSTATS is provided if gnet_stats_copy_app +was called. + + +Locking: +-------- + +Locks are taken before writing and released once all statistics have +been written. Locks are always released in case of an error. You +are responsible for making sure that the lock is initialized. + + +Rate Estimator: +--------------- + +0) Prepare an estimator attribute. Most likely this would be in user + space. The value of this TLV should contain a tc_estimator structure. + As usual, such a TLV needs to be 32 bit aligned and therefore the + length needs to be appropriately set, etc. The estimator interval + and ewma log need to be converted to the appropriate values. + tc_estimator.c::tc_setup_estimator() is advisable to be used as the + conversion routine. It does a few clever things. It takes a time + interval in microsecs, a time constant also in microsecs and a struct + tc_estimator to be populated. The returned tc_estimator can be + transported to the kernel. Transfer such a structure in a TLV of type + TCA_RATE to your code in the kernel. + +In the kernel when setting up: + +1) make sure you have basic stats and rate stats setup first. +2) make sure you have initialized stats lock that is used to setup such + stats. +3) Now initialize a new estimator:: + + int ret = gen_new_estimator(my_basicstats,my_rate_est_stats, + mystats_lock, attr_with_tcestimator_struct); + + if ret == 0 + success + else + failed + +From now on, every time you dump my_rate_est_stats it will contain +up-to-date info. + +Once you are done, call gen_kill_estimator(my_basicstats, +my_rate_est_stats) Make sure that my_basicstats and my_rate_est_stats +are still valid (i.e still exist) at the time of making this call. + + +Authors: +-------- +- Thomas Graf <tgraf@suug.ch> +- Jamal Hadi Salim <hadi@cyberus.ca> diff --git a/Documentation/networking/generic-hdlc.rst b/Documentation/networking/generic-hdlc.rst new file mode 100644 index 0000000000..1c3bb5cb98 --- /dev/null +++ b/Documentation/networking/generic-hdlc.rst @@ -0,0 +1,170 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================== +Generic HDLC layer +================== + +Krzysztof Halasa <khc@pm.waw.pl> + + +Generic HDLC layer currently supports: + +1. Frame Relay (ANSI, CCITT, Cisco and no LMI) + + - Normal (routed) and Ethernet-bridged (Ethernet device emulation) + interfaces can share a single PVC. + - ARP support (no InARP support in the kernel - there is an + experimental InARP user-space daemon available on: + http://www.kernel.org/pub/linux/utils/net/hdlc/). + +2. raw HDLC - either IP (IPv4) interface or Ethernet device emulation +3. Cisco HDLC +4. PPP +5. X.25 (uses X.25 routines). + +Generic HDLC is a protocol driver only - it needs a low-level driver +for your particular hardware. + +Ethernet device emulation (using HDLC or Frame-Relay PVC) is compatible +with IEEE 802.1Q (VLANs) and 802.1D (Ethernet bridging). + + +Make sure the hdlc.o and the hardware driver are loaded. It should +create a number of "hdlc" (hdlc0 etc) network devices, one for each +WAN port. You'll need the "sethdlc" utility, get it from: + + http://www.kernel.org/pub/linux/utils/net/hdlc/ + +Compile sethdlc.c utility:: + + gcc -O2 -Wall -o sethdlc sethdlc.c + +Make sure you're using a correct version of sethdlc for your kernel. + +Use sethdlc to set physical interface, clock rate, HDLC mode used, +and add any required PVCs if using Frame Relay. +Usually you want something like:: + + sethdlc hdlc0 clock int rate 128000 + sethdlc hdlc0 cisco interval 10 timeout 25 + +or:: + + sethdlc hdlc0 rs232 clock ext + sethdlc hdlc0 fr lmi ansi + sethdlc hdlc0 create 99 + ifconfig hdlc0 up + ifconfig pvc0 localIP pointopoint remoteIP + +In Frame Relay mode, ifconfig master hdlc device up (without assigning +any IP address to it) before using pvc devices. + + +Setting interface: + +* v35 | rs232 | x21 | t1 | e1 + - sets physical interface for a given port + if the card has software-selectable interfaces + loopback + - activate hardware loopback (for testing only) +* clock ext + - both RX clock and TX clock external +* clock int + - both RX clock and TX clock internal +* clock txint + - RX clock external, TX clock internal +* clock txfromrx + - RX clock external, TX clock derived from RX clock +* rate + - sets clock rate in bps (for "int" or "txint" clock only) + + +Setting protocol: + +* hdlc - sets raw HDLC (IP-only) mode + + nrz / nrzi / fm-mark / fm-space / manchester - sets transmission code + + no-parity / crc16 / crc16-pr0 (CRC16 with preset zeros) / crc32-itu + + crc16-itu (CRC16 with ITU-T polynomial) / crc16-itu-pr0 - sets parity + +* hdlc-eth - Ethernet device emulation using HDLC. Parity and encoding + as above. + +* cisco - sets Cisco HDLC mode (IP, IPv6 and IPX supported) + + interval - time in seconds between keepalive packets + + timeout - time in seconds after last received keepalive packet before + we assume the link is down + +* ppp - sets synchronous PPP mode + +* x25 - sets X.25 mode + +* fr - Frame Relay mode + + lmi ansi / ccitt / cisco / none - LMI (link management) type + + dce - Frame Relay DCE (network) side LMI instead of default DTE (user). + + It has nothing to do with clocks! + + - t391 - link integrity verification polling timer (in seconds) - user + - t392 - polling verification timer (in seconds) - network + - n391 - full status polling counter - user + - n392 - error threshold - both user and network + - n393 - monitored events count - both user and network + +Frame-Relay only: + +* create n | delete n - adds / deletes PVC interface with DLCI #n. + Newly created interface will be named pvc0, pvc1 etc. + +* create ether n | delete ether n - adds a device for Ethernet-bridged + frames. The device will be named pvceth0, pvceth1 etc. + + + + +Board-specific issues +--------------------- + +n2.o and c101.o need parameters to work:: + + insmod n2 hw=io,irq,ram,ports[:io,irq,...] + +example:: + + insmod n2 hw=0x300,10,0xD0000,01 + +or:: + + insmod c101 hw=irq,ram[:irq,...] + +example:: + + insmod c101 hw=9,0xdc000 + +If built into the kernel, these drivers need kernel (command line) parameters:: + + n2.hw=io,irq,ram,ports:... + +or:: + + c101.hw=irq,ram:... + + + +If you have a problem with N2, C101 or PLX200SYN card, you can issue the +"private" command to see port's packet descriptor rings (in kernel logs):: + + sethdlc hdlc0 private + +The hardware driver has to be build with #define DEBUG_RINGS. +Attaching this info to bug reports would be helpful. Anyway, let me know +if you have problems using this. + +For patches and other info look at: +<http://www.kernel.org/pub/linux/utils/net/hdlc/>. diff --git a/Documentation/networking/generic_netlink.rst b/Documentation/networking/generic_netlink.rst new file mode 100644 index 0000000000..d960dbd7e8 --- /dev/null +++ b/Documentation/networking/generic_netlink.rst @@ -0,0 +1,9 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=============== +Generic Netlink +=============== + +A wiki document on how to use Generic Netlink can be found here: + + * https://wiki.linuxfoundation.org/networking/generic_netlink_howto diff --git a/Documentation/networking/gtp.rst b/Documentation/networking/gtp.rst new file mode 100644 index 0000000000..9a7835cc14 --- /dev/null +++ b/Documentation/networking/gtp.rst @@ -0,0 +1,251 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================================== +The Linux kernel GTP tunneling module +===================================== + +Documentation by + Harald Welte <laforge@gnumonks.org> and + Andreas Schultz <aschultz@tpip.net> + +In 'drivers/net/gtp.c' you are finding a kernel-level implementation +of a GTP tunnel endpoint. + +What is GTP +=========== + +GTP is the Generic Tunnel Protocol, which is a 3GPP protocol used for +tunneling User-IP payload between a mobile station (phone, modem) +and the interconnection between an external packet data network (such +as the internet). + +So when you start a 'data connection' from your mobile phone, the +phone will use the control plane to signal for the establishment of +such a tunnel between that external data network and the phone. The +tunnel endpoints thus reside on the phone and in the gateway. All +intermediate nodes just transport the encapsulated packet. + +The phone itself does not implement GTP but uses some other +technology-dependent protocol stack for transmitting the user IP +payload, such as LLC/SNDCP/RLC/MAC. + +At some network element inside the cellular operator infrastructure +(SGSN in case of GPRS/EGPRS or classic UMTS, hNodeB in case of a 3G +femtocell, eNodeB in case of 4G/LTE), the cellular protocol stacking +is translated into GTP *without breaking the end-to-end tunnel*. So +intermediate nodes just perform some specific relay function. + +At some point the GTP packet ends up on the so-called GGSN (GSM/UMTS) +or P-GW (LTE), which terminates the tunnel, decapsulates the packet +and forwards it onto an external packet data network. This can be +public internet, but can also be any private IP network (or even +theoretically some non-IP network like X.25). + +You can find the protocol specification in 3GPP TS 29.060, available +publicly via the 3GPP website at http://www.3gpp.org/DynaReport/29060.htm + +A direct PDF link to v13.6.0 is provided for convenience below: +http://www.etsi.org/deliver/etsi_ts/129000_129099/129060/13.06.00_60/ts_129060v130600p.pdf + +The Linux GTP tunnelling module +=============================== + +The module implements the function of a tunnel endpoint, i.e. it is +able to decapsulate tunneled IP packets in the uplink originated by +the phone, and encapsulate raw IP packets received from the external +packet network in downlink towards the phone. + +It *only* implements the so-called 'user plane', carrying the User-IP +payload, called GTP-U. It does not implement the 'control plane', +which is a signaling protocol used for establishment and teardown of +GTP tunnels (GTP-C). + +So in order to have a working GGSN/P-GW setup, you will need a +userspace program that implements the GTP-C protocol and which then +uses the netlink interface provided by the GTP-U module in the kernel +to configure the kernel module. + +This split architecture follows the tunneling modules of other +protocols, e.g. PPPoE or L2TP, where you also run a userspace daemon +to handle the tunnel establishment, authentication etc. and only the +data plane is accelerated inside the kernel. + +Don't be confused by terminology: The GTP User Plane goes through +kernel accelerated path, while the GTP Control Plane goes to +Userspace :) + +The official homepage of the module is at +https://osmocom.org/projects/linux-kernel-gtp-u/wiki + +Userspace Programs with Linux Kernel GTP-U support +================================================== + +At the time of this writing, there are at least two Free Software +implementations that implement GTP-C and can use the netlink interface +to make use of the Linux kernel GTP-U support: + +* OpenGGSN (classic 2G/3G GGSN in C): + https://osmocom.org/projects/openggsn/wiki/OpenGGSN + +* ergw (GGSN + P-GW in Erlang): + https://github.com/travelping/ergw + +Userspace Library / Command Line Utilities +========================================== + +There is a userspace library called 'libgtpnl' which is based on +libmnl and which implements a C-language API towards the netlink +interface provided by the Kernel GTP module: + +http://git.osmocom.org/libgtpnl/ + +Protocol Versions +================= + +There are two different versions of GTP-U: v0 [GSM TS 09.60] and v1 +[3GPP TS 29.281]. Both are implemented in the Kernel GTP module. +Version 0 is a legacy version, and deprecated from recent 3GPP +specifications. + +GTP-U uses UDP for transporting PDUs. The receiving UDP port is 2151 +for GTPv1-U and 3386 for GTPv0-U. + +There are three versions of GTP-C: v0, v1, and v2. As the kernel +doesn't implement GTP-C, we don't have to worry about this. It's the +responsibility of the control plane implementation in userspace to +implement that. + +IPv6 +==== + +The 3GPP specifications indicate either IPv4 or IPv6 can be used both +on the inner (user) IP layer, or on the outer (transport) layer. + +Unfortunately, the Kernel module currently supports IPv6 neither for +the User IP payload, nor for the outer IP layer. Patches or other +Contributions to fix this are most welcome! + +Mailing List +============ + +If you have questions regarding how to use the Kernel GTP module from +your own software, or want to contribute to the code, please use the +osmocom-net-grps mailing list for related discussion. The list can be +reached at osmocom-net-gprs@lists.osmocom.org and the mailman +interface for managing your subscription is at +https://lists.osmocom.org/mailman/listinfo/osmocom-net-gprs + +Issue Tracker +============= + +The Osmocom project maintains an issue tracker for the Kernel GTP-U +module at +https://osmocom.org/projects/linux-kernel-gtp-u/issues + +History / Acknowledgements +========================== + +The Module was originally created in 2012 by Harald Welte, but never +completed. Pablo came in to finish the mess Harald left behind. But +doe to a lack of user interest, it never got merged. + +In 2015, Andreas Schultz came to the rescue and fixed lots more bugs, +extended it with new features and finally pushed all of us to get it +mainline, where it was merged in 4.7.0. + +Architectural Details +===================== + +Local GTP-U entity and tunnel identification +-------------------------------------------- + +GTP-U uses UDP for transporting PDU's. The receiving UDP port is 2152 +for GTPv1-U and 3386 for GTPv0-U. + +There is only one GTP-U entity (and therefore SGSN/GGSN/S-GW/PDN-GW +instance) per IP address. Tunnel Endpoint Identifier (TEID) are unique +per GTP-U entity. + +A specific tunnel is only defined by the destination entity. Since the +destination port is constant, only the destination IP and TEID define +a tunnel. The source IP and Port have no meaning for the tunnel. + +Therefore: + + * when sending, the remote entity is defined by the remote IP and + the tunnel endpoint id. The source IP and port have no meaning and + can be changed at any time. + + * when receiving the local entity is defined by the local + destination IP and the tunnel endpoint id. The source IP and port + have no meaning and can change at any time. + +[3GPP TS 29.281] Section 4.3.0 defines this so:: + + The TEID in the GTP-U header is used to de-multiplex traffic + incoming from remote tunnel endpoints so that it is delivered to the + User plane entities in a way that allows multiplexing of different + users, different packet protocols and different QoS levels. + Therefore no two remote GTP-U endpoints shall send traffic to a + GTP-U protocol entity using the same TEID value except + for data forwarding as part of mobility procedures. + +The definition above only defines that two remote GTP-U endpoints +*should not* send to the same TEID, it *does not* forbid or exclude +such a scenario. In fact, the mentioned mobility procedures make it +necessary that the GTP-U entity accepts traffic for TEIDs from +multiple or unknown peers. + +Therefore, the receiving side identifies tunnels exclusively based on +TEIDs, not based on the source IP! + +APN vs. Network Device +====================== + +The GTP-U driver creates a Linux network device for each Gi/SGi +interface. + +[3GPP TS 29.281] calls the Gi/SGi reference point an interface. This +may lead to the impression that the GGSN/P-GW can have only one such +interface. + +Correct is that the Gi/SGi reference point defines the interworking +between +the 3GPP packet domain (PDN) based on GTP-U tunnel and IP +based networks. + +There is no provision in any of the 3GPP documents that limits the +number of Gi/SGi interfaces implemented by a GGSN/P-GW. + +[3GPP TS 29.061] Section 11.3 makes it clear that the selection of a +specific Gi/SGi interfaces is made through the Access Point Name +(APN):: + + 2. each private network manages its own addressing. In general this + will result in different private networks having overlapping + address ranges. A logically separate connection (e.g. an IP in IP + tunnel or layer 2 virtual circuit) is used between the GGSN/P-GW + and each private network. + + In this case the IP address alone is not necessarily unique. The + pair of values, Access Point Name (APN) and IPv4 address and/or + IPv6 prefixes, is unique. + +In order to support the overlapping address range use case, each APN +is mapped to a separate Gi/SGi interface (network device). + +.. note:: + + The Access Point Name is purely a control plane (GTP-C) concept. + At the GTP-U level, only Tunnel Endpoint Identifiers are present in + GTP-U packets and network devices are known + +Therefore for a given UE the mapping in IP to PDN network is: + + * network device + MS IP -> Peer IP + Peer TEID, + +and from PDN to IP network: + + * local GTP-U IP + TEID -> network device + +Furthermore, before a received T-PDU is injected into the network +device the MS IP is checked against the IP recorded in PDP context. diff --git a/Documentation/networking/ieee802154.rst b/Documentation/networking/ieee802154.rst new file mode 100644 index 0000000000..c652d383fe --- /dev/null +++ b/Documentation/networking/ieee802154.rst @@ -0,0 +1,182 @@ +=============================== +IEEE 802.15.4 Developer's Guide +=============================== + +Introduction +============ +The IEEE 802.15.4 working group focuses on standardization of the bottom +two layers: Medium Access Control (MAC) and Physical access (PHY). And there +are mainly two options available for upper layers: + +- ZigBee - proprietary protocol from the ZigBee Alliance +- 6LoWPAN - IPv6 networking over low rate personal area networks + +The goal of the Linux-wpan is to provide a complete implementation +of the IEEE 802.15.4 and 6LoWPAN protocols. IEEE 802.15.4 is a stack +of protocols for organizing Low-Rate Wireless Personal Area Networks. + +The stack is composed of three main parts: + +- IEEE 802.15.4 layer; We have chosen to use plain Berkeley socket API, + the generic Linux networking stack to transfer IEEE 802.15.4 data + messages and a special protocol over netlink for configuration/management +- MAC - provides access to shared channel and reliable data delivery +- PHY - represents device drivers + +Socket API +========== + +:: + + int sd = socket(PF_IEEE802154, SOCK_DGRAM, 0); + +The address family, socket addresses etc. are defined in the +include/net/af_ieee802154.h header or in the special header +in the userspace package (see either https://linux-wpan.org/wpan-tools.html +or the git tree at https://github.com/linux-wpan/wpan-tools). + +6LoWPAN Linux implementation +============================ + +The IEEE 802.15.4 standard specifies an MTU of 127 bytes, yielding about 80 +octets of actual MAC payload once security is turned on, on a wireless link +with a link throughput of 250 kbps or less. The 6LoWPAN adaptation format +[RFC4944] was specified to carry IPv6 datagrams over such constrained links, +taking into account limited bandwidth, memory, or energy resources that are +expected in applications such as wireless Sensor Networks. [RFC4944] defines +a Mesh Addressing header to support sub-IP forwarding, a Fragmentation header +to support the IPv6 minimum MTU requirement [RFC2460], and stateless header +compression for IPv6 datagrams (LOWPAN_HC1 and LOWPAN_HC2) to reduce the +relatively large IPv6 and UDP headers down to (in the best case) several bytes. + +In September 2011 the standard update was published - [RFC6282]. +It deprecates HC1 and HC2 compression and defines IPHC encoding format which is +used in this Linux implementation. + +All the code related to 6lowpan you may find in files: net/6lowpan/* +and net/ieee802154/6lowpan/* + +To setup a 6LoWPAN interface you need: +1. Add IEEE802.15.4 interface and set channel and PAN ID; +2. Add 6lowpan interface by command like: +# ip link add link wpan0 name lowpan0 type lowpan +3. Bring up 'lowpan0' interface + +Drivers +======= + +Like with WiFi, there are several types of devices implementing IEEE 802.15.4. +1) 'HardMAC'. The MAC layer is implemented in the device itself, the device +exports a management (e.g. MLME) and data API. +2) 'SoftMAC' or just radio. These types of devices are just radio transceivers +possibly with some kinds of acceleration like automatic CRC computation and +comparison, automagic ACK handling, address matching, etc. + +Those types of devices require different approach to be hooked into Linux kernel. + +HardMAC +------- + +See the header include/net/ieee802154_netdev.h. You have to implement Linux +net_device, with .type = ARPHRD_IEEE802154. Data is exchanged with socket family +code via plain sk_buffs. On skb reception skb->cb must contain additional +info as described in the struct ieee802154_mac_cb. During packet transmission +the skb->cb is used to provide additional data to device's header_ops->create +function. Be aware that this data can be overridden later (when socket code +submits skb to qdisc), so if you need something from that cb later, you should +store info in the skb->data on your own. + +To hook the MLME interface you have to populate the ml_priv field of your +net_device with a pointer to struct ieee802154_mlme_ops instance. The fields +assoc_req, assoc_resp, disassoc_req, start_req, and scan_req are optional. +All other fields are required. + +SoftMAC +------- + +The MAC is the middle layer in the IEEE 802.15.4 Linux stack. This moment it +provides interface for drivers registration and management of slave interfaces. + +NOTE: Currently the only monitor device type is supported - it's IEEE 802.15.4 +stack interface for network sniffers (e.g. WireShark). + +This layer is going to be extended soon. + +See header include/net/mac802154.h and several drivers in +drivers/net/ieee802154/. + +Fake drivers +------------ + +In addition there is a driver available which simulates a real device with +SoftMAC (fakelb - IEEE 802.15.4 loopback driver) interface. This option +provides a possibility to test and debug the stack without usage of real hardware. + +Device drivers API +================== + +The include/net/mac802154.h defines following functions: + +.. c:function:: struct ieee802154_dev *ieee802154_alloc_device (size_t priv_size, struct ieee802154_ops *ops) + +Allocation of IEEE 802.15.4 compatible device. + +.. c:function:: void ieee802154_free_device(struct ieee802154_dev *dev) + +Freeing allocated device. + +.. c:function:: int ieee802154_register_device(struct ieee802154_dev *dev) + +Register PHY in the system. + +.. c:function:: void ieee802154_unregister_device(struct ieee802154_dev *dev) + +Freeing registered PHY. + +.. c:function:: void ieee802154_rx_irqsafe(struct ieee802154_hw *hw, struct sk_buff *skb, u8 lqi) + +Telling 802.15.4 module there is a new received frame in the skb with +the RF Link Quality Indicator (LQI) from the hardware device. + +.. c:function:: void ieee802154_xmit_complete(struct ieee802154_hw *hw, struct sk_buff *skb, bool ifs_handling) + +Telling 802.15.4 module the frame in the skb is or going to be +transmitted through the hardware device + +The device driver must implement the following callbacks in the IEEE 802.15.4 +operations structure at least:: + + struct ieee802154_ops { + ... + int (*start)(struct ieee802154_hw *hw); + void (*stop)(struct ieee802154_hw *hw); + ... + int (*xmit_async)(struct ieee802154_hw *hw, struct sk_buff *skb); + int (*ed)(struct ieee802154_hw *hw, u8 *level); + int (*set_channel)(struct ieee802154_hw *hw, u8 page, u8 channel); + ... + }; + +.. c:function:: int start(struct ieee802154_hw *hw) + +Handler that 802.15.4 module calls for the hardware device initialization. + +.. c:function:: void stop(struct ieee802154_hw *hw) + +Handler that 802.15.4 module calls for the hardware device cleanup. + +.. c:function:: int xmit_async(struct ieee802154_hw *hw, struct sk_buff *skb) + +Handler that 802.15.4 module calls for each frame in the skb going to be +transmitted through the hardware device. + +.. c:function:: int ed(struct ieee802154_hw *hw, u8 *level) + +Handler that 802.15.4 module calls for Energy Detection from the hardware +device. + +.. c:function:: int set_channel(struct ieee802154_hw *hw, u8 page, u8 channel) + +Set radio for listening on specific channel of the hardware device. + +Moreover IEEE 802.15.4 device operations structure should be filled. diff --git a/Documentation/networking/ila.rst b/Documentation/networking/ila.rst new file mode 100644 index 0000000000..5ac0a6270b --- /dev/null +++ b/Documentation/networking/ila.rst @@ -0,0 +1,296 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=================================== +Identifier Locator Addressing (ILA) +=================================== + + +Introduction +============ + +Identifier-locator addressing (ILA) is a technique used with IPv6 that +differentiates between location and identity of a network node. Part of an +address expresses the immutable identity of the node, and another part +indicates the location of the node which can be dynamic. Identifier-locator +addressing can be used to efficiently implement overlay networks for +network virtualization as well as solutions for use cases in mobility. + +ILA can be thought of as means to implement an overlay network without +encapsulation. This is accomplished by performing network address +translation on destination addresses as a packet traverses a network. To +the network, an ILA translated packet appears to be no different than any +other IPv6 packet. For instance, if the transport protocol is TCP then an +ILA translated packet looks like just another TCP/IPv6 packet. The +advantage of this is that ILA is transparent to the network so that +optimizations in the network, such as ECMP, RSS, GRO, GSO, etc., just work. + +The ILA protocol is described in Internet-Draft draft-herbert-intarea-ila. + + +ILA terminology +=============== + + - Identifier + A number that identifies an addressable node in the network + independent of its location. ILA identifiers are sixty-four + bit values. + + - Locator + A network prefix that routes to a physical host. Locators + provide the topological location of an addressed node. ILA + locators are sixty-four bit prefixes. + + - ILA mapping + A mapping of an ILA identifier to a locator (or to a + locator and meta data). An ILA domain maintains a database + that contains mappings for all destinations in the domain. + + - SIR address + An IPv6 address composed of a SIR prefix (upper sixty- + four bits) and an identifier (lower sixty-four bits). + SIR addresses are visible to applications and provide a + means for them to address nodes independent of their + location. + + - ILA address + An IPv6 address composed of a locator (upper sixty-four + bits) and an identifier (low order sixty-four bits). ILA + addresses are never visible to an application. + + - ILA host + An end host that is capable of performing ILA translations + on transmit or receive. + + - ILA router + A network node that performs ILA translation and forwarding + of translated packets. + + - ILA forwarding cache + A type of ILA router that only maintains a working set + cache of mappings. + + - ILA node + A network node capable of performing ILA translations. This + can be an ILA router, ILA forwarding cache, or ILA host. + + +Operation +========= + +There are two fundamental operations with ILA: + + - Translate a SIR address to an ILA address. This is performed on ingress + to an ILA overlay. + + - Translate an ILA address to a SIR address. This is performed on egress + from the ILA overlay. + +ILA can be deployed either on end hosts or intermediate devices in the +network; these are provided by "ILA hosts" and "ILA routers" respectively. +Configuration and datapath for these two points of deployment is somewhat +different. + +The diagram below illustrates the flow of packets through ILA as well +as showing ILA hosts and routers:: + + +--------+ +--------+ + | Host A +-+ +--->| Host B | + | | | (2) ILA (') | | + +--------+ | ...addressed.... ( ) +--------+ + V +---+--+ . packet . +---+--+ (_) + (1) SIR | | ILA |----->-------->---->| ILA | | (3) SIR + addressed +->|router| . . |router|->-+ addressed + packet +---+--+ . IPv6 . +---+--+ packet + / . Network . + / . . +--+-++--------+ + +--------+ / . . |ILA || Host | + | Host +--+ . .- -|host|| | + | | . . +--+-++--------+ + +--------+ ................ + + +Transport checksum handling +=========================== + +When an address is translated by ILA, an encapsulated transport checksum +that includes the translated address in a pseudo header may be rendered +incorrect on the wire. This is a problem for intermediate devices, +including checksum offload in NICs, that process the checksum. There are +three options to deal with this: + +- no action Allow the checksum to be incorrect on the wire. Before + a receiver verifies a checksum the ILA to SIR address + translation must be done. + +- adjust transport checksum + When ILA translation is performed the packet is parsed + and if a transport layer checksum is found then it is + adjusted to reflect the correct checksum per the + translated address. + +- checksum neutral mapping + When an address is translated the difference can be offset + elsewhere in a part of the packet that is covered by + the checksum. The low order sixteen bits of the identifier + are used. This method is preferred since it doesn't require + parsing a packet beyond the IP header and in most cases the + adjustment can be precomputed and saved with the mapping. + +Note that the checksum neutral adjustment affects the low order sixteen +bits of the identifier. When ILA to SIR address translation is done on +egress the low order bits are restored to the original value which +restores the identifier as it was originally sent. + + +Identifier types +================ + +ILA defines different types of identifiers for different use cases. + +The defined types are: + + 0: interface identifier + + 1: locally unique identifier + + 2: virtual networking identifier for IPv4 address + + 3: virtual networking identifier for IPv6 unicast address + + 4: virtual networking identifier for IPv6 multicast address + + 5: non-local address identifier + +In the current implementation of kernel ILA only locally unique identifiers +(LUID) are supported. LUID allows for a generic, unformatted 64 bit +identifier. + + +Identifier formats +================== + +Kernel ILA supports two optional fields in an identifier for formatting: +"C-bit" and "identifier type". The presence of these fields is determined +by configuration as demonstrated below. + +If the identifier type is present it occupies the three highest order +bits of an identifier. The possible values are given in the above list. + +If the C-bit is present, this is used as an indication that checksum +neutral mapping has been done. The C-bit can only be set in an +ILA address, never a SIR address. + +In the simplest format the identifier types, C-bit, and checksum +adjustment value are not present so an identifier is considered an +unstructured sixty-four bit value:: + + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Identifier | + + + + | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +The checksum neutral adjustment may be configured to always be +present using neutral-map-auto. In this case there is no C-bit, but the +checksum adjustment is in the low order 16 bits. The identifier is +still sixty-four bits:: + + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Identifier | + | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | Checksum-neutral adjustment | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +The C-bit may used to explicitly indicate that checksum neutral +mapping has been applied to an ILA address. The format is:: + + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | |C| Identifier | + | +-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | Checksum-neutral adjustment | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +The identifier type field may be present to indicate the identifier +type. If it is not present then the type is inferred based on mapping +configuration. The checksum neutral adjustment may automatically +used with the identifier type as illustrated below:: + + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Type| Identifier | + +-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | Checksum-neutral adjustment | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +If the identifier type and the C-bit can be present simultaneously so +the identifier format would be:: + + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Type|C| Identifier | + +-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | Checksum-neutral adjustment | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + +Configuration +============= + +There are two methods to configure ILA mappings. One is by using LWT routes +and the other is ila_xlat (called from NFHOOK PREROUTING hook). ila_xlat +is intended to be used in the receive path for ILA hosts . + +An ILA router has also been implemented in XDP. Description of that is +outside the scope of this document. + +The usage of for ILA LWT routes is: + +ip route add DEST/128 encap ila LOC csum-mode MODE ident-type TYPE via ADDR + +Destination (DEST) can either be a SIR address (for an ILA host or ingress +ILA router) or an ILA address (egress ILA router). LOC is the sixty-four +bit locator (with format W:X:Y:Z) that overwrites the upper sixty-four +bits of the destination address. Checksum MODE is one of "no-action", +"adj-transport", "neutral-map", and "neutral-map-auto". If neutral-map is +set then the C-bit will be present. Identifier TYPE one of "luid" or +"use-format." In the case of use-format, the identifier type field is +present and the effective type is taken from that. + +The usage of ila_xlat is: + +ip ila add loc_match MATCH loc LOC csum-mode MODE ident-type TYPE + +MATCH indicates the incoming locator that must be matched to apply +a the translaiton. LOC is the locator that overwrites the upper +sixty-four bits of the destination address. MODE and TYPE have the +same meanings as described above. + + +Some examples +============= + +:: + + # Configure an ILA route that uses checksum neutral mapping as well + # as type field. Note that the type field is set in the SIR address + # (the 2000 implies type is 1 which is LUID). + ip route add 3333:0:0:1:2000:0:1:87/128 encap ila 2001:0:87:0 \ + csum-mode neutral-map ident-type use-format + + # Configure an ILA LWT route that uses auto checksum neutral mapping + # (no C-bit) and configure identifier type to be LUID so that the + # identifier type field will not be present. + ip route add 3333:0:0:1:2000:0:2:87/128 encap ila 2001:0:87:1 \ + csum-mode neutral-map-auto ident-type luid + + ila_xlat configuration + + # Configure an ILA to SIR mapping that matches a locator and overwrites + # it with a SIR address (3333:0:0:1 in this example). The C-bit and + # identifier field are used. + ip ila add loc_match 2001:0:119:0 loc 3333:0:0:1 \ + csum-mode neutral-map-auto ident-type use-format + + # Configure an ILA to SIR mapping where checksum neutral is automatically + # set without the C-bit and the identifier type is configured to be LUID + # so that the identifier type field is not present. + ip ila add loc_match 2001:0:119:0 loc 3333:0:0:1 \ + csum-mode neutral-map-auto ident-type use-format diff --git a/Documentation/networking/index.rst b/Documentation/networking/index.rst new file mode 100644 index 0000000000..5b75c3f7a1 --- /dev/null +++ b/Documentation/networking/index.rst @@ -0,0 +1,132 @@ +Networking +========== + +Refer to :ref:`netdev-FAQ` for a guide on netdev development process specifics. + +Contents: + +.. toctree:: + :maxdepth: 2 + + af_xdp + bareudp + batman-adv + can + can_ucan_protocol + device_drivers/index + dsa/index + devlink/index + caif/index + ethtool-netlink + ieee802154 + j1939 + kapi + msg_zerocopy + failover + net_dim + net_failover + page_pool + phy + sfp-phylink + alias + bridge + snmp_counter + checksum-offloads + segmentation-offloads + scaling + tls + tls-offload + tls-handshake + nfc + 6lowpan + 6pack + arcnet-hardware + arcnet + atm + ax25 + bonding + cdc_mbim + dccp + dctcp + dns_resolver + driver + eql + fib_trie + filter + generic-hdlc + generic_netlink + gen_stats + gtp + ila + ioam6-sysctl + ipddp + ip_dynaddr + ipsec + ip-sysctl + ipv6 + ipvlan + ipvs-sysctl + kcm + l2tp + lapb-module + mac80211-injection + mctp + mpls-sysctl + mptcp-sysctl + multiqueue + napi + netconsole + netdev-features + netdevices + netfilter-sysctl + netif-msg + nexthop-group-resilient + nf_conntrack-sysctl + nf_flowtable + openvswitch + operstates + packet_mmap + phonet + pktgen + plip + ppp_generic + proc_net_tcp + radiotap-headers + rds + regulatory + representors + rxrpc + sctp + secid + seg6-sysctl + skbuff + smc-sysctl + statistics + strparser + switchdev + sysfs-tagging + tc-actions-env-rules + tc-queue-filters + tcp-thin + team + timestamping + tipc + tproxy + tuntap + udplite + vrf + vxlan + x25 + x25-iface + xfrm_device + xfrm_proc + xfrm_sync + xfrm_sysctl + xdp-rx-metadata + +.. only:: subproject and html + + Indices + ======= + + * :ref:`genindex` diff --git a/Documentation/networking/ioam6-sysctl.rst b/Documentation/networking/ioam6-sysctl.rst new file mode 100644 index 0000000000..c18cab2c48 --- /dev/null +++ b/Documentation/networking/ioam6-sysctl.rst @@ -0,0 +1,26 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================== +IOAM6 Sysfs variables +===================== + + +/proc/sys/net/conf/<iface>/ioam6_* variables: +============================================= + +ioam6_enabled - BOOL + Accept (= enabled) or ignore (= disabled) IPv6 IOAM options on ingress + for this interface. + + * 0 - disabled (default) + * 1 - enabled + +ioam6_id - SHORT INTEGER + Define the IOAM id of this interface. + + Default is ~0. + +ioam6_id_wide - INTEGER + Define the wide IOAM id of this interface. + + Default is ~0. diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst new file mode 100644 index 0000000000..a66054d076 --- /dev/null +++ b/Documentation/networking/ip-sysctl.rst @@ -0,0 +1,3208 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========= +IP Sysctl +========= + +/proc/sys/net/ipv4/* Variables +============================== + +ip_forward - BOOLEAN + - 0 - disabled (default) + - not 0 - enabled + + Forward Packets between interfaces. + + This variable is special, its change resets all configuration + parameters to their default state (RFC1122 for hosts, RFC1812 + for routers) + +ip_default_ttl - INTEGER + Default value of TTL field (Time To Live) for outgoing (but not + forwarded) IP packets. Should be between 1 and 255 inclusive. + Default: 64 (as recommended by RFC1700) + +ip_no_pmtu_disc - INTEGER + Disable Path MTU Discovery. If enabled in mode 1 and a + fragmentation-required ICMP is received, the PMTU to this + destination will be set to the smallest of the old MTU to + this destination and min_pmtu (see below). You will need + to raise min_pmtu to the smallest interface MTU on your system + manually if you want to avoid locally generated fragments. + + In mode 2 incoming Path MTU Discovery messages will be + discarded. Outgoing frames are handled the same as in mode 1, + implicitly setting IP_PMTUDISC_DONT on every created socket. + + Mode 3 is a hardened pmtu discover mode. The kernel will only + accept fragmentation-needed errors if the underlying protocol + can verify them besides a plain socket lookup. Current + protocols for which pmtu events will be honored are TCP, SCTP + and DCCP as they verify e.g. the sequence number or the + association. This mode should not be enabled globally but is + only intended to secure e.g. name servers in namespaces where + TCP path mtu must still work but path MTU information of other + protocols should be discarded. If enabled globally this mode + could break other protocols. + + Possible values: 0-3 + + Default: FALSE + +min_pmtu - INTEGER + default 552 - minimum Path MTU. Unless this is changed manually, + each cached pmtu will never be lower than this setting. + +ip_forward_use_pmtu - BOOLEAN + By default we don't trust protocol path MTUs while forwarding + because they could be easily forged and can lead to unwanted + fragmentation by the router. + You only need to enable this if you have user-space software + which tries to discover path mtus by itself and depends on the + kernel honoring this information. This is normally not the + case. + + Default: 0 (disabled) + + Possible values: + + - 0 - disabled + - 1 - enabled + +fwmark_reflect - BOOLEAN + Controls the fwmark of kernel-generated IPv4 reply packets that are not + associated with a socket for example, TCP RSTs or ICMP echo replies). + If unset, these packets have a fwmark of zero. If set, they have the + fwmark of the packet they are replying to. + + Default: 0 + +fib_multipath_use_neigh - BOOLEAN + Use status of existing neighbor entry when determining nexthop for + multipath routes. If disabled, neighbor information is not used and + packets could be directed to a failed nexthop. Only valid for kernels + built with CONFIG_IP_ROUTE_MULTIPATH enabled. + + Default: 0 (disabled) + + Possible values: + + - 0 - disabled + - 1 - enabled + +fib_multipath_hash_policy - INTEGER + Controls which hash policy to use for multipath routes. Only valid + for kernels built with CONFIG_IP_ROUTE_MULTIPATH enabled. + + Default: 0 (Layer 3) + + Possible values: + + - 0 - Layer 3 + - 1 - Layer 4 + - 2 - Layer 3 or inner Layer 3 if present + - 3 - Custom multipath hash. Fields used for multipath hash calculation + are determined by fib_multipath_hash_fields sysctl + +fib_multipath_hash_fields - UNSIGNED INTEGER + When fib_multipath_hash_policy is set to 3 (custom multipath hash), the + fields used for multipath hash calculation are determined by this + sysctl. + + This value is a bitmask which enables various fields for multipath hash + calculation. + + Possible fields are: + + ====== ============================ + 0x0001 Source IP address + 0x0002 Destination IP address + 0x0004 IP protocol + 0x0008 Unused (Flow Label) + 0x0010 Source port + 0x0020 Destination port + 0x0040 Inner source IP address + 0x0080 Inner destination IP address + 0x0100 Inner IP protocol + 0x0200 Inner Flow Label + 0x0400 Inner source port + 0x0800 Inner destination port + ====== ============================ + + Default: 0x0007 (source IP, destination IP and IP protocol) + +fib_sync_mem - UNSIGNED INTEGER + Amount of dirty memory from fib entries that can be backlogged before + synchronize_rcu is forced. + + Default: 512kB Minimum: 64kB Maximum: 64MB + +ip_forward_update_priority - INTEGER + Whether to update SKB priority from "TOS" field in IPv4 header after it + is forwarded. The new SKB priority is mapped from TOS field value + according to an rt_tos2priority table (see e.g. man tc-prio). + + Default: 1 (Update priority.) + + Possible values: + + - 0 - Do not update priority. + - 1 - Update priority. + +route/max_size - INTEGER + Maximum number of routes allowed in the kernel. Increase + this when using large numbers of interfaces and/or routes. + + From linux kernel 3.6 onwards, this is deprecated for ipv4 + as route cache is no longer used. + + From linux kernel 6.3 onwards, this is deprecated for ipv6 + as garbage collection manages cached route entries. + +neigh/default/gc_thresh1 - INTEGER + Minimum number of entries to keep. Garbage collector will not + purge entries if there are fewer than this number. + + Default: 128 + +neigh/default/gc_thresh2 - INTEGER + Threshold when garbage collector becomes more aggressive about + purging entries. Entries older than 5 seconds will be cleared + when over this number. + + Default: 512 + +neigh/default/gc_thresh3 - INTEGER + Maximum number of non-PERMANENT neighbor entries allowed. Increase + this when using large numbers of interfaces and when communicating + with large numbers of directly-connected peers. + + Default: 1024 + +neigh/default/unres_qlen_bytes - INTEGER + The maximum number of bytes which may be used by packets + queued for each unresolved address by other network layers. + (added in linux 3.3) + + Setting negative value is meaningless and will return error. + + Default: SK_WMEM_MAX, (same as net.core.wmem_default). + + Exact value depends on architecture and kernel options, + but should be enough to allow queuing 256 packets + of medium size. + +neigh/default/unres_qlen - INTEGER + The maximum number of packets which may be queued for each + unresolved address by other network layers. + + (deprecated in linux 3.3) : use unres_qlen_bytes instead. + + Prior to linux 3.3, the default value is 3 which may cause + unexpected packet loss. The current default value is calculated + according to default value of unres_qlen_bytes and true size of + packet. + + Default: 101 + +neigh/default/interval_probe_time_ms - INTEGER + The probe interval for neighbor entries with NTF_MANAGED flag, + the min value is 1. + + Default: 5000 + +mtu_expires - INTEGER + Time, in seconds, that cached PMTU information is kept. + +min_adv_mss - INTEGER + The advertised MSS depends on the first hop route MTU, but will + never be lower than this setting. + +fib_notify_on_flag_change - INTEGER + Whether to emit RTM_NEWROUTE notifications whenever RTM_F_OFFLOAD/ + RTM_F_TRAP/RTM_F_OFFLOAD_FAILED flags are changed. + + After installing a route to the kernel, user space receives an + acknowledgment, which means the route was installed in the kernel, + but not necessarily in hardware. + It is also possible for a route already installed in hardware to change + its action and therefore its flags. For example, a host route that is + trapping packets can be "promoted" to perform decapsulation following + the installation of an IPinIP/VXLAN tunnel. + The notifications will indicate to user-space the state of the route. + + Default: 0 (Do not emit notifications.) + + Possible values: + + - 0 - Do not emit notifications. + - 1 - Emit notifications. + - 2 - Emit notifications only for RTM_F_OFFLOAD_FAILED flag change. + +IP Fragmentation: + +ipfrag_high_thresh - LONG INTEGER + Maximum memory used to reassemble IP fragments. + +ipfrag_low_thresh - LONG INTEGER + (Obsolete since linux-4.17) + Maximum memory used to reassemble IP fragments before the kernel + begins to remove incomplete fragment queues to free up resources. + The kernel still accepts new fragments for defragmentation. + +ipfrag_time - INTEGER + Time in seconds to keep an IP fragment in memory. + +ipfrag_max_dist - INTEGER + ipfrag_max_dist is a non-negative integer value which defines the + maximum "disorder" which is allowed among fragments which share a + common IP source address. Note that reordering of packets is + not unusual, but if a large number of fragments arrive from a source + IP address while a particular fragment queue remains incomplete, it + probably indicates that one or more fragments belonging to that queue + have been lost. When ipfrag_max_dist is positive, an additional check + is done on fragments before they are added to a reassembly queue - if + ipfrag_max_dist (or more) fragments have arrived from a particular IP + address between additions to any IP fragment queue using that source + address, it's presumed that one or more fragments in the queue are + lost. The existing fragment queue will be dropped, and a new one + started. An ipfrag_max_dist value of zero disables this check. + + Using a very small value, e.g. 1 or 2, for ipfrag_max_dist can + result in unnecessarily dropping fragment queues when normal + reordering of packets occurs, which could lead to poor application + performance. Using a very large value, e.g. 50000, increases the + likelihood of incorrectly reassembling IP fragments that originate + from different IP datagrams, which could result in data corruption. + Default: 64 + +bc_forwarding - INTEGER + bc_forwarding enables the feature described in rfc1812#section-5.3.5.2 + and rfc2644. It allows the router to forward directed broadcast. + To enable this feature, the 'all' entry and the input interface entry + should be set to 1. + Default: 0 + +INET peer storage +================= + +inet_peer_threshold - INTEGER + The approximate size of the storage. Starting from this threshold + entries will be thrown aggressively. This threshold also determines + entries' time-to-live and time intervals between garbage collection + passes. More entries, less time-to-live, less GC interval. + +inet_peer_minttl - INTEGER + Minimum time-to-live of entries. Should be enough to cover fragment + time-to-live on the reassembling side. This minimum time-to-live is + guaranteed if the pool size is less than inet_peer_threshold. + Measured in seconds. + +inet_peer_maxttl - INTEGER + Maximum time-to-live of entries. Unused entries will expire after + this period of time if there is no memory pressure on the pool (i.e. + when the number of entries in the pool is very small). + Measured in seconds. + +TCP variables +============= + +somaxconn - INTEGER + Limit of socket listen() backlog, known in userspace as SOMAXCONN. + Defaults to 4096. (Was 128 before linux-5.4) + See also tcp_max_syn_backlog for additional tuning for TCP sockets. + +tcp_abort_on_overflow - BOOLEAN + If listening service is too slow to accept new connections, + reset them. Default state is FALSE. It means that if overflow + occurred due to a burst, connection will recover. Enable this + option _only_ if you are really sure that listening daemon + cannot be tuned to accept connections faster. Enabling this + option can harm clients of your server. + +tcp_adv_win_scale - INTEGER + Obsolete since linux-6.6 + Count buffering overhead as bytes/2^tcp_adv_win_scale + (if tcp_adv_win_scale > 0) or bytes-bytes/2^(-tcp_adv_win_scale), + if it is <= 0. + + Possible values are [-31, 31], inclusive. + + Default: 1 + +tcp_allowed_congestion_control - STRING + Show/set the congestion control choices available to non-privileged + processes. The list is a subset of those listed in + tcp_available_congestion_control. + + Default is "reno" and the default setting (tcp_congestion_control). + +tcp_app_win - INTEGER + Reserve max(window/2^tcp_app_win, mss) of window for application + buffer. Value 0 is special, it means that nothing is reserved. + + Possible values are [0, 31], inclusive. + + Default: 31 + +tcp_autocorking - BOOLEAN + Enable TCP auto corking : + When applications do consecutive small write()/sendmsg() system calls, + we try to coalesce these small writes as much as possible, to lower + total amount of sent packets. This is done if at least one prior + packet for the flow is waiting in Qdisc queues or device transmit + queue. Applications can still use TCP_CORK for optimal behavior + when they know how/when to uncork their sockets. + + Default : 1 + +tcp_available_congestion_control - STRING + Shows the available congestion control choices that are registered. + More congestion control algorithms may be available as modules, + but not loaded. + +tcp_base_mss - INTEGER + The initial value of search_low to be used by the packetization layer + Path MTU discovery (MTU probing). If MTU probing is enabled, + this is the initial MSS used by the connection. + +tcp_mtu_probe_floor - INTEGER + If MTU probing is enabled this caps the minimum MSS used for search_low + for the connection. + + Default : 48 + +tcp_min_snd_mss - INTEGER + TCP SYN and SYNACK messages usually advertise an ADVMSS option, + as described in RFC 1122 and RFC 6691. + + If this ADVMSS option is smaller than tcp_min_snd_mss, + it is silently capped to tcp_min_snd_mss. + + Default : 48 (at least 8 bytes of payload per segment) + +tcp_congestion_control - STRING + Set the congestion control algorithm to be used for new + connections. The algorithm "reno" is always available, but + additional choices may be available based on kernel configuration. + Default is set as part of kernel configuration. + For passive connections, the listener congestion control choice + is inherited. + + [see setsockopt(listenfd, SOL_TCP, TCP_CONGESTION, "name" ...) ] + +tcp_dsack - BOOLEAN + Allows TCP to send "duplicate" SACKs. + +tcp_early_retrans - INTEGER + Tail loss probe (TLP) converts RTOs occurring due to tail + losses into fast recovery (draft-ietf-tcpm-rack). Note that + TLP requires RACK to function properly (see tcp_recovery below) + + Possible values: + + - 0 disables TLP + - 3 or 4 enables TLP + + Default: 3 + +tcp_ecn - INTEGER + Control use of Explicit Congestion Notification (ECN) by TCP. + ECN is used only when both ends of the TCP connection indicate + support for it. This feature is useful in avoiding losses due + to congestion by allowing supporting routers to signal + congestion before having to drop packets. + + Possible values are: + + = ===================================================== + 0 Disable ECN. Neither initiate nor accept ECN. + 1 Enable ECN when requested by incoming connections and + also request ECN on outgoing connection attempts. + 2 Enable ECN when requested by incoming connections + but do not request ECN on outgoing connections. + = ===================================================== + + Default: 2 + +tcp_ecn_fallback - BOOLEAN + If the kernel detects that ECN connection misbehaves, enable fall + back to non-ECN. Currently, this knob implements the fallback + from RFC3168, section 6.1.1.1., but we reserve that in future, + additional detection mechanisms could be implemented under this + knob. The value is not used, if tcp_ecn or per route (or congestion + control) ECN settings are disabled. + + Default: 1 (fallback enabled) + +tcp_fack - BOOLEAN + This is a legacy option, it has no effect anymore. + +tcp_fin_timeout - INTEGER + The length of time an orphaned (no longer referenced by any + application) connection will remain in the FIN_WAIT_2 state + before it is aborted at the local end. While a perfectly + valid "receive only" state for an un-orphaned connection, an + orphaned connection in FIN_WAIT_2 state could otherwise wait + forever for the remote to close its end of the connection. + + Cf. tcp_max_orphans + + Default: 60 seconds + +tcp_frto - INTEGER + Enables Forward RTO-Recovery (F-RTO) defined in RFC5682. + F-RTO is an enhanced recovery algorithm for TCP retransmission + timeouts. It is particularly beneficial in networks where the + RTT fluctuates (e.g., wireless). F-RTO is sender-side only + modification. It does not require any support from the peer. + + By default it's enabled with a non-zero value. 0 disables F-RTO. + +tcp_fwmark_accept - BOOLEAN + If set, incoming connections to listening sockets that do not have a + socket mark will set the mark of the accepting socket to the fwmark of + the incoming SYN packet. This will cause all packets on that connection + (starting from the first SYNACK) to be sent with that fwmark. The + listening socket's mark is unchanged. Listening sockets that already + have a fwmark set via setsockopt(SOL_SOCKET, SO_MARK, ...) are + unaffected. + + Default: 0 + +tcp_invalid_ratelimit - INTEGER + Limit the maximal rate for sending duplicate acknowledgments + in response to incoming TCP packets that are for an existing + connection but that are invalid due to any of these reasons: + + (a) out-of-window sequence number, + (b) out-of-window acknowledgment number, or + (c) PAWS (Protection Against Wrapped Sequence numbers) check failure + + This can help mitigate simple "ack loop" DoS attacks, wherein + a buggy or malicious middlebox or man-in-the-middle can + rewrite TCP header fields in manner that causes each endpoint + to think that the other is sending invalid TCP segments, thus + causing each side to send an unterminating stream of duplicate + acknowledgments for invalid segments. + + Using 0 disables rate-limiting of dupacks in response to + invalid segments; otherwise this value specifies the minimal + space between sending such dupacks, in milliseconds. + + Default: 500 (milliseconds). + +tcp_keepalive_time - INTEGER + How often TCP sends out keepalive messages when keepalive is enabled. + Default: 2hours. + +tcp_keepalive_probes - INTEGER + How many keepalive probes TCP sends out, until it decides that the + connection is broken. Default value: 9. + +tcp_keepalive_intvl - INTEGER + How frequently the probes are send out. Multiplied by + tcp_keepalive_probes it is time to kill not responding connection, + after probes started. Default value: 75sec i.e. connection + will be aborted after ~11 minutes of retries. + +tcp_l3mdev_accept - BOOLEAN + Enables child sockets to inherit the L3 master device index. + Enabling this option allows a "global" listen socket to work + across L3 master domains (e.g., VRFs) with connected sockets + derived from the listen socket to be bound to the L3 domain in + which the packets originated. Only valid when the kernel was + compiled with CONFIG_NET_L3_MASTER_DEV. + + Default: 0 (disabled) + +tcp_low_latency - BOOLEAN + This is a legacy option, it has no effect anymore. + +tcp_max_orphans - INTEGER + Maximal number of TCP sockets not attached to any user file handle, + held by system. If this number is exceeded orphaned connections are + reset immediately and warning is printed. This limit exists + only to prevent simple DoS attacks, you _must_ not rely on this + or lower the limit artificially, but rather increase it + (probably, after increasing installed memory), + if network conditions require more than default value, + and tune network services to linger and kill such states + more aggressively. Let me to remind again: each orphan eats + up to ~64K of unswappable memory. + +tcp_max_syn_backlog - INTEGER + Maximal number of remembered connection requests (SYN_RECV), + which have not received an acknowledgment from connecting client. + + This is a per-listener limit. + + The minimal value is 128 for low memory machines, and it will + increase in proportion to the memory of machine. + + If server suffers from overload, try increasing this number. + + Remember to also check /proc/sys/net/core/somaxconn + A SYN_RECV request socket consumes about 304 bytes of memory. + +tcp_max_tw_buckets - INTEGER + Maximal number of timewait sockets held by system simultaneously. + If this number is exceeded time-wait socket is immediately destroyed + and warning is printed. This limit exists only to prevent + simple DoS attacks, you _must_ not lower the limit artificially, + but rather increase it (probably, after increasing installed memory), + if network conditions require more than default value. + +tcp_mem - vector of 3 INTEGERs: min, pressure, max + min: below this number of pages TCP is not bothered about its + memory appetite. + + pressure: when amount of memory allocated by TCP exceeds this number + of pages, TCP moderates its memory consumption and enters memory + pressure mode, which is exited when memory consumption falls + under "min". + + max: number of pages allowed for queueing by all TCP sockets. + + Defaults are calculated at boot time from amount of available + memory. + +tcp_min_rtt_wlen - INTEGER + The window length of the windowed min filter to track the minimum RTT. + A shorter window lets a flow more quickly pick up new (higher) + minimum RTT when it is moved to a longer path (e.g., due to traffic + engineering). A longer window makes the filter more resistant to RTT + inflations such as transient congestion. The unit is seconds. + + Possible values: 0 - 86400 (1 day) + + Default: 300 + +tcp_moderate_rcvbuf - BOOLEAN + If set, TCP performs receive buffer auto-tuning, attempting to + automatically size the buffer (no greater than tcp_rmem[2]) to + match the size required by the path for full throughput. Enabled by + default. + +tcp_mtu_probing - INTEGER + Controls TCP Packetization-Layer Path MTU Discovery. Takes three + values: + + - 0 - Disabled + - 1 - Disabled by default, enabled when an ICMP black hole detected + - 2 - Always enabled, use initial MSS of tcp_base_mss. + +tcp_probe_interval - UNSIGNED INTEGER + Controls how often to start TCP Packetization-Layer Path MTU + Discovery reprobe. The default is reprobing every 10 minutes as + per RFC4821. + +tcp_probe_threshold - INTEGER + Controls when TCP Packetization-Layer Path MTU Discovery probing + will stop in respect to the width of search range in bytes. Default + is 8 bytes. + +tcp_no_metrics_save - BOOLEAN + By default, TCP saves various connection metrics in the route cache + when the connection closes, so that connections established in the + near future can use these to set initial conditions. Usually, this + increases overall performance, but may sometimes cause performance + degradation. If set, TCP will not cache metrics on closing + connections. + +tcp_no_ssthresh_metrics_save - BOOLEAN + Controls whether TCP saves ssthresh metrics in the route cache. + + Default is 1, which disables ssthresh metrics. + +tcp_orphan_retries - INTEGER + This value influences the timeout of a locally closed TCP connection, + when RTO retransmissions remain unacknowledged. + See tcp_retries2 for more details. + + The default value is 8. + + If your machine is a loaded WEB server, + you should think about lowering this value, such sockets + may consume significant resources. Cf. tcp_max_orphans. + +tcp_recovery - INTEGER + This value is a bitmap to enable various experimental loss recovery + features. + + ========= ============================================================= + RACK: 0x1 enables the RACK loss detection for fast detection of lost + retransmissions and tail drops. It also subsumes and disables + RFC6675 recovery for SACK connections. + + RACK: 0x2 makes RACK's reordering window static (min_rtt/4). + + RACK: 0x4 disables RACK's DUPACK threshold heuristic + ========= ============================================================= + + Default: 0x1 + +tcp_reflect_tos - BOOLEAN + For listening sockets, reuse the DSCP value of the initial SYN message + for outgoing packets. This allows to have both directions of a TCP + stream to use the same DSCP value, assuming DSCP remains unchanged for + the lifetime of the connection. + + This options affects both IPv4 and IPv6. + + Default: 0 (disabled) + +tcp_reordering - INTEGER + Initial reordering level of packets in a TCP stream. + TCP stack can then dynamically adjust flow reordering level + between this initial value and tcp_max_reordering + + Default: 3 + +tcp_max_reordering - INTEGER + Maximal reordering level of packets in a TCP stream. + 300 is a fairly conservative value, but you might increase it + if paths are using per packet load balancing (like bonding rr mode) + + Default: 300 + +tcp_retrans_collapse - BOOLEAN + Bug-to-bug compatibility with some broken printers. + On retransmit try to send bigger packets to work around bugs in + certain TCP stacks. + +tcp_retries1 - INTEGER + This value influences the time, after which TCP decides, that + something is wrong due to unacknowledged RTO retransmissions, + and reports this suspicion to the network layer. + See tcp_retries2 for more details. + + RFC 1122 recommends at least 3 retransmissions, which is the + default. + +tcp_retries2 - INTEGER + This value influences the timeout of an alive TCP connection, + when RTO retransmissions remain unacknowledged. + Given a value of N, a hypothetical TCP connection following + exponential backoff with an initial RTO of TCP_RTO_MIN would + retransmit N times before killing the connection at the (N+1)th RTO. + + The default value of 15 yields a hypothetical timeout of 924.6 + seconds and is a lower bound for the effective timeout. + TCP will effectively time out at the first RTO which exceeds the + hypothetical timeout. + + RFC 1122 recommends at least 100 seconds for the timeout, + which corresponds to a value of at least 8. + +tcp_rfc1337 - BOOLEAN + If set, the TCP stack behaves conforming to RFC1337. If unset, + we are not conforming to RFC, but prevent TCP TIME_WAIT + assassination. + + Default: 0 + +tcp_rmem - vector of 3 INTEGERs: min, default, max + min: Minimal size of receive buffer used by TCP sockets. + It is guaranteed to each TCP socket, even under moderate memory + pressure. + + Default: 4K + + default: initial size of receive buffer used by TCP sockets. + This value overrides net.core.rmem_default used by other protocols. + Default: 131072 bytes. + This value results in initial window of 65535. + + max: maximal size of receive buffer allowed for automatically + selected receiver buffers for TCP socket. This value does not override + net.core.rmem_max. Calling setsockopt() with SO_RCVBUF disables + automatic tuning of that socket's receive buffer size, in which + case this value is ignored. + Default: between 131072 and 6MB, depending on RAM size. + +tcp_sack - BOOLEAN + Enable select acknowledgments (SACKS). + +tcp_comp_sack_delay_ns - LONG INTEGER + TCP tries to reduce number of SACK sent, using a timer + based on 5% of SRTT, capped by this sysctl, in nano seconds. + The default is 1ms, based on TSO autosizing period. + + Default : 1,000,000 ns (1 ms) + +tcp_comp_sack_slack_ns - LONG INTEGER + This sysctl control the slack used when arming the + timer used by SACK compression. This gives extra time + for small RTT flows, and reduces system overhead by allowing + opportunistic reduction of timer interrupts. + + Default : 100,000 ns (100 us) + +tcp_comp_sack_nr - INTEGER + Max number of SACK that can be compressed. + Using 0 disables SACK compression. + + Default : 44 + +tcp_slow_start_after_idle - BOOLEAN + If set, provide RFC2861 behavior and time out the congestion + window after an idle period. An idle period is defined at + the current RTO. If unset, the congestion window will not + be timed out after an idle period. + + Default: 1 + +tcp_stdurg - BOOLEAN + Use the Host requirements interpretation of the TCP urgent pointer field. + Most hosts use the older BSD interpretation, so if you turn this on + Linux might not communicate correctly with them. + + Default: FALSE + +tcp_synack_retries - INTEGER + Number of times SYNACKs for a passive TCP connection attempt will + be retransmitted. Should not be higher than 255. Default value + is 5, which corresponds to 31seconds till the last retransmission + with the current initial RTO of 1second. With this the final timeout + for a passive TCP connection will happen after 63seconds. + +tcp_syncookies - INTEGER + Only valid when the kernel was compiled with CONFIG_SYN_COOKIES + Send out syncookies when the syn backlog queue of a socket + overflows. This is to prevent against the common 'SYN flood attack' + Default: 1 + + Note, that syncookies is fallback facility. + It MUST NOT be used to help highly loaded servers to stand + against legal connection rate. If you see SYN flood warnings + in your logs, but investigation shows that they occur + because of overload with legal connections, you should tune + another parameters until this warning disappear. + See: tcp_max_syn_backlog, tcp_synack_retries, tcp_abort_on_overflow. + + syncookies seriously violate TCP protocol, do not allow + to use TCP extensions, can result in serious degradation + of some services (f.e. SMTP relaying), visible not by you, + but your clients and relays, contacting you. While you see + SYN flood warnings in logs not being really flooded, your server + is seriously misconfigured. + + If you want to test which effects syncookies have to your + network connections you can set this knob to 2 to enable + unconditionally generation of syncookies. + +tcp_migrate_req - BOOLEAN + The incoming connection is tied to a specific listening socket when + the initial SYN packet is received during the three-way handshake. + When a listener is closed, in-flight request sockets during the + handshake and established sockets in the accept queue are aborted. + + If the listener has SO_REUSEPORT enabled, other listeners on the + same port should have been able to accept such connections. This + option makes it possible to migrate such child sockets to another + listener after close() or shutdown(). + + The BPF_SK_REUSEPORT_SELECT_OR_MIGRATE type of eBPF program should + usually be used to define the policy to pick an alive listener. + Otherwise, the kernel will randomly pick an alive listener only if + this option is enabled. + + Note that migration between listeners with different settings may + crash applications. Let's say migration happens from listener A to + B, and only B has TCP_SAVE_SYN enabled. B cannot read SYN data from + the requests migrated from A. To avoid such a situation, cancel + migration by returning SK_DROP in the type of eBPF program, or + disable this option. + + Default: 0 + +tcp_fastopen - INTEGER + Enable TCP Fast Open (RFC7413) to send and accept data in the opening + SYN packet. + + The client support is enabled by flag 0x1 (on by default). The client + then must use sendmsg() or sendto() with the MSG_FASTOPEN flag, + rather than connect() to send data in SYN. + + The server support is enabled by flag 0x2 (off by default). Then + either enable for all listeners with another flag (0x400) or + enable individual listeners via TCP_FASTOPEN socket option with + the option value being the length of the syn-data backlog. + + The values (bitmap) are + + ===== ======== ====================================================== + 0x1 (client) enables sending data in the opening SYN on the client. + 0x2 (server) enables the server support, i.e., allowing data in + a SYN packet to be accepted and passed to the + application before 3-way handshake finishes. + 0x4 (client) send data in the opening SYN regardless of cookie + availability and without a cookie option. + 0x200 (server) accept data-in-SYN w/o any cookie option present. + 0x400 (server) enable all listeners to support Fast Open by + default without explicit TCP_FASTOPEN socket option. + ===== ======== ====================================================== + + Default: 0x1 + + Note that additional client or server features are only + effective if the basic support (0x1 and 0x2) are enabled respectively. + +tcp_fastopen_blackhole_timeout_sec - INTEGER + Initial time period in second to disable Fastopen on active TCP sockets + when a TFO firewall blackhole issue happens. + This time period will grow exponentially when more blackhole issues + get detected right after Fastopen is re-enabled and will reset to + initial value when the blackhole issue goes away. + 0 to disable the blackhole detection. + + By default, it is set to 0 (feature is disabled). + +tcp_fastopen_key - list of comma separated 32-digit hexadecimal INTEGERs + The list consists of a primary key and an optional backup key. The + primary key is used for both creating and validating cookies, while the + optional backup key is only used for validating cookies. The purpose of + the backup key is to maximize TFO validation when keys are rotated. + + A randomly chosen primary key may be configured by the kernel if + the tcp_fastopen sysctl is set to 0x400 (see above), or if the + TCP_FASTOPEN setsockopt() optname is set and a key has not been + previously configured via sysctl. If keys are configured via + setsockopt() by using the TCP_FASTOPEN_KEY optname, then those + per-socket keys will be used instead of any keys that are specified via + sysctl. + + A key is specified as 4 8-digit hexadecimal integers which are separated + by a '-' as: xxxxxxxx-xxxxxxxx-xxxxxxxx-xxxxxxxx. Leading zeros may be + omitted. A primary and a backup key may be specified by separating them + by a comma. If only one key is specified, it becomes the primary key and + any previously configured backup keys are removed. + +tcp_syn_retries - INTEGER + Number of times initial SYNs for an active TCP connection attempt + will be retransmitted. Should not be higher than 127. Default value + is 6, which corresponds to 67seconds (with tcp_syn_linear_timeouts = 4) + till the last retransmission with the current initial RTO of 1second. + With this the final timeout for an active TCP connection attempt + will happen after 131seconds. + +tcp_timestamps - INTEGER + Enable timestamps as defined in RFC1323. + + - 0: Disabled. + - 1: Enable timestamps as defined in RFC1323 and use random offset for + each connection rather than only using the current time. + - 2: Like 1, but without random offsets. + + Default: 1 + +tcp_min_tso_segs - INTEGER + Minimal number of segments per TSO frame. + + Since linux-3.12, TCP does an automatic sizing of TSO frames, + depending on flow rate, instead of filling 64Kbytes packets. + For specific usages, it's possible to force TCP to build big + TSO frames. Note that TCP stack might split too big TSO packets + if available window is too small. + + Default: 2 + +tcp_tso_rtt_log - INTEGER + Adjustment of TSO packet sizes based on min_rtt + + Starting from linux-5.18, TCP autosizing can be tweaked + for flows having small RTT. + + Old autosizing was splitting the pacing budget to send 1024 TSO + per second. + + tso_packet_size = sk->sk_pacing_rate / 1024; + + With the new mechanism, we increase this TSO sizing using: + + distance = min_rtt_usec / (2^tcp_tso_rtt_log) + tso_packet_size += gso_max_size >> distance; + + This means that flows between very close hosts can use bigger + TSO packets, reducing their cpu costs. + + If you want to use the old autosizing, set this sysctl to 0. + + Default: 9 (2^9 = 512 usec) + +tcp_pacing_ss_ratio - INTEGER + sk->sk_pacing_rate is set by TCP stack using a ratio applied + to current rate. (current_rate = cwnd * mss / srtt) + If TCP is in slow start, tcp_pacing_ss_ratio is applied + to let TCP probe for bigger speeds, assuming cwnd can be + doubled every other RTT. + + Default: 200 + +tcp_pacing_ca_ratio - INTEGER + sk->sk_pacing_rate is set by TCP stack using a ratio applied + to current rate. (current_rate = cwnd * mss / srtt) + If TCP is in congestion avoidance phase, tcp_pacing_ca_ratio + is applied to conservatively probe for bigger throughput. + + Default: 120 + +tcp_syn_linear_timeouts - INTEGER + The number of times for an active TCP connection to retransmit SYNs with + a linear backoff timeout before defaulting to an exponential backoff + timeout. This has no effect on SYNACK at the passive TCP side. + + With an initial RTO of 1 and tcp_syn_linear_timeouts = 4 we would + expect SYN RTOs to be: 1, 1, 1, 1, 1, 2, 4, ... (4 linear timeouts, + and the first exponential backoff using 2^0 * initial_RTO). + Default: 4 + +tcp_tso_win_divisor - INTEGER + This allows control over what percentage of the congestion window + can be consumed by a single TSO frame. + The setting of this parameter is a choice between burstiness and + building larger TSO frames. + + Default: 3 + +tcp_tw_reuse - INTEGER + Enable reuse of TIME-WAIT sockets for new connections when it is + safe from protocol viewpoint. + + - 0 - disable + - 1 - global enable + - 2 - enable for loopback traffic only + + It should not be changed without advice/request of technical + experts. + + Default: 2 + +tcp_window_scaling - BOOLEAN + Enable window scaling as defined in RFC1323. + +tcp_shrink_window - BOOLEAN + This changes how the TCP receive window is calculated. + + RFC 7323, section 2.4, says there are instances when a retracted + window can be offered, and that TCP implementations MUST ensure + that they handle a shrinking window, as specified in RFC 1122. + + - 0 - Disabled. The window is never shrunk. + - 1 - Enabled. The window is shrunk when necessary to remain within + the memory limit set by autotuning (sk_rcvbuf). + This only occurs if a non-zero receive window + scaling factor is also in effect. + + Default: 0 + +tcp_wmem - vector of 3 INTEGERs: min, default, max + min: Amount of memory reserved for send buffers for TCP sockets. + Each TCP socket has rights to use it due to fact of its birth. + + Default: 4K + + default: initial size of send buffer used by TCP sockets. This + value overrides net.core.wmem_default used by other protocols. + + It is usually lower than net.core.wmem_default. + + Default: 16K + + max: Maximal amount of memory allowed for automatically tuned + send buffers for TCP sockets. This value does not override + net.core.wmem_max. Calling setsockopt() with SO_SNDBUF disables + automatic tuning of that socket's send buffer size, in which case + this value is ignored. + + Default: between 64K and 4MB, depending on RAM size. + +tcp_notsent_lowat - UNSIGNED INTEGER + A TCP socket can control the amount of unsent bytes in its write queue, + thanks to TCP_NOTSENT_LOWAT socket option. poll()/select()/epoll() + reports POLLOUT events if the amount of unsent bytes is below a per + socket value, and if the write queue is not full. sendmsg() will + also not add new buffers if the limit is hit. + + This global variable controls the amount of unsent data for + sockets not using TCP_NOTSENT_LOWAT. For these sockets, a change + to the global variable has immediate effect. + + Default: UINT_MAX (0xFFFFFFFF) + +tcp_workaround_signed_windows - BOOLEAN + If set, assume no receipt of a window scaling option means the + remote TCP is broken and treats the window as a signed quantity. + If unset, assume the remote TCP is not broken even if we do + not receive a window scaling option from them. + + Default: 0 + +tcp_thin_linear_timeouts - BOOLEAN + Enable dynamic triggering of linear timeouts for thin streams. + If set, a check is performed upon retransmission by timeout to + determine if the stream is thin (less than 4 packets in flight). + As long as the stream is found to be thin, up to 6 linear + timeouts may be performed before exponential backoff mode is + initiated. This improves retransmission latency for + non-aggressive thin streams, often found to be time-dependent. + For more information on thin streams, see + Documentation/networking/tcp-thin.rst + + Default: 0 + +tcp_limit_output_bytes - INTEGER + Controls TCP Small Queue limit per tcp socket. + TCP bulk sender tends to increase packets in flight until it + gets losses notifications. With SNDBUF autotuning, this can + result in a large amount of packets queued on the local machine + (e.g.: qdiscs, CPU backlog, or device) hurting latency of other + flows, for typical pfifo_fast qdiscs. tcp_limit_output_bytes + limits the number of bytes on qdisc or device to reduce artificial + RTT/cwnd and reduce bufferbloat. + + Default: 1048576 (16 * 65536) + +tcp_challenge_ack_limit - INTEGER + Limits number of Challenge ACK sent per second, as recommended + in RFC 5961 (Improving TCP's Robustness to Blind In-Window Attacks) + Note that this per netns rate limit can allow some side channel + attacks and probably should not be enabled. + TCP stack implements per TCP socket limits anyway. + Default: INT_MAX (unlimited) + +tcp_ehash_entries - INTEGER + Show the number of hash buckets for TCP sockets in the current + networking namespace. + + A negative value means the networking namespace does not own its + hash buckets and shares the initial networking namespace's one. + +tcp_child_ehash_entries - INTEGER + Control the number of hash buckets for TCP sockets in the child + networking namespace, which must be set before clone() or unshare(). + + If the value is not 0, the kernel uses a value rounded up to 2^n + as the actual hash bucket size. 0 is a special value, meaning + the child networking namespace will share the initial networking + namespace's hash buckets. + + Note that the child will use the global one in case the kernel + fails to allocate enough memory. In addition, the global hash + buckets are spread over available NUMA nodes, but the allocation + of the child hash table depends on the current process's NUMA + policy, which could result in performance differences. + + Note also that the default value of tcp_max_tw_buckets and + tcp_max_syn_backlog depend on the hash bucket size. + + Possible values: 0, 2^n (n: 0 - 24 (16Mi)) + + Default: 0 + +tcp_plb_enabled - BOOLEAN + If set and the underlying congestion control (e.g. DCTCP) supports + and enables PLB feature, TCP PLB (Protective Load Balancing) is + enabled. PLB is described in the following paper: + https://doi.org/10.1145/3544216.3544226. Based on PLB parameters, + upon sensing sustained congestion, TCP triggers a change in + flow label field for outgoing IPv6 packets. A change in flow label + field potentially changes the path of outgoing packets for switches + that use ECMP/WCMP for routing. + + PLB changes socket txhash which results in a change in IPv6 Flow Label + field, and currently no-op for IPv4 headers. It is possible + to apply PLB for IPv4 with other network header fields (e.g. TCP + or IPv4 options) or using encapsulation where outer header is used + by switches to determine next hop. In either case, further host + and switch side changes will be needed. + + When set, PLB assumes that congestion signal (e.g. ECN) is made + available and used by congestion control module to estimate a + congestion measure (e.g. ce_ratio). PLB needs a congestion measure to + make repathing decisions. + + Default: FALSE + +tcp_plb_idle_rehash_rounds - INTEGER + Number of consecutive congested rounds (RTT) seen after which + a rehash can be performed, given there are no packets in flight. + This is referred to as M in PLB paper: + https://doi.org/10.1145/3544216.3544226. + + Possible Values: 0 - 31 + + Default: 3 + +tcp_plb_rehash_rounds - INTEGER + Number of consecutive congested rounds (RTT) seen after which + a forced rehash can be performed. Be careful when setting this + parameter, as a small value increases the risk of retransmissions. + This is referred to as N in PLB paper: + https://doi.org/10.1145/3544216.3544226. + + Possible Values: 0 - 31 + + Default: 12 + +tcp_plb_suspend_rto_sec - INTEGER + Time, in seconds, to suspend PLB in event of an RTO. In order to avoid + having PLB repath onto a connectivity "black hole", after an RTO a TCP + connection suspends PLB repathing for a random duration between 1x and + 2x of this parameter. Randomness is added to avoid concurrent rehashing + of multiple TCP connections. This should be set corresponding to the + amount of time it takes to repair a failed link. + + Possible Values: 0 - 255 + + Default: 60 + +tcp_plb_cong_thresh - INTEGER + Fraction of packets marked with congestion over a round (RTT) to + tag that round as congested. This is referred to as K in the PLB paper: + https://doi.org/10.1145/3544216.3544226. + + The 0-1 fraction range is mapped to 0-256 range to avoid floating + point operations. For example, 128 means that if at least 50% of + the packets in a round were marked as congested then the round + will be tagged as congested. + + Setting threshold to 0 means that PLB repaths every RTT regardless + of congestion. This is not intended behavior for PLB and should be + used only for experimentation purpose. + + Possible Values: 0 - 256 + + Default: 128 + +UDP variables +============= + +udp_l3mdev_accept - BOOLEAN + Enabling this option allows a "global" bound socket to work + across L3 master domains (e.g., VRFs) with packets capable of + being received regardless of the L3 domain in which they + originated. Only valid when the kernel was compiled with + CONFIG_NET_L3_MASTER_DEV. + + Default: 0 (disabled) + +udp_mem - vector of 3 INTEGERs: min, pressure, max + Number of pages allowed for queueing by all UDP sockets. + + min: Number of pages allowed for queueing by all UDP sockets. + + pressure: This value was introduced to follow format of tcp_mem. + + max: This value was introduced to follow format of tcp_mem. + + Default is calculated at boot time from amount of available memory. + +udp_rmem_min - INTEGER + Minimal size of receive buffer used by UDP sockets in moderation. + Each UDP socket is able to use the size for receiving data, even if + total pages of UDP sockets exceed udp_mem pressure. The unit is byte. + + Default: 4K + +udp_wmem_min - INTEGER + UDP does not have tx memory accounting and this tunable has no effect. + +udp_hash_entries - INTEGER + Show the number of hash buckets for UDP sockets in the current + networking namespace. + + A negative value means the networking namespace does not own its + hash buckets and shares the initial networking namespace's one. + +udp_child_ehash_entries - INTEGER + Control the number of hash buckets for UDP sockets in the child + networking namespace, which must be set before clone() or unshare(). + + If the value is not 0, the kernel uses a value rounded up to 2^n + as the actual hash bucket size. 0 is a special value, meaning + the child networking namespace will share the initial networking + namespace's hash buckets. + + Note that the child will use the global one in case the kernel + fails to allocate enough memory. In addition, the global hash + buckets are spread over available NUMA nodes, but the allocation + of the child hash table depends on the current process's NUMA + policy, which could result in performance differences. + + Possible values: 0, 2^n (n: 7 (128) - 16 (64K)) + + Default: 0 + + +RAW variables +============= + +raw_l3mdev_accept - BOOLEAN + Enabling this option allows a "global" bound socket to work + across L3 master domains (e.g., VRFs) with packets capable of + being received regardless of the L3 domain in which they + originated. Only valid when the kernel was compiled with + CONFIG_NET_L3_MASTER_DEV. + + Default: 1 (enabled) + +CIPSOv4 Variables +================= + +cipso_cache_enable - BOOLEAN + If set, enable additions to and lookups from the CIPSO label mapping + cache. If unset, additions are ignored and lookups always result in a + miss. However, regardless of the setting the cache is still + invalidated when required when means you can safely toggle this on and + off and the cache will always be "safe". + + Default: 1 + +cipso_cache_bucket_size - INTEGER + The CIPSO label cache consists of a fixed size hash table with each + hash bucket containing a number of cache entries. This variable limits + the number of entries in each hash bucket; the larger the value is, the + more CIPSO label mappings that can be cached. When the number of + entries in a given hash bucket reaches this limit adding new entries + causes the oldest entry in the bucket to be removed to make room. + + Default: 10 + +cipso_rbm_optfmt - BOOLEAN + Enable the "Optimized Tag 1 Format" as defined in section 3.4.2.6 of + the CIPSO draft specification (see Documentation/netlabel for details). + This means that when set the CIPSO tag will be padded with empty + categories in order to make the packet data 32-bit aligned. + + Default: 0 + +cipso_rbm_structvalid - BOOLEAN + If set, do a very strict check of the CIPSO option when + ip_options_compile() is called. If unset, relax the checks done during + ip_options_compile(). Either way is "safe" as errors are caught else + where in the CIPSO processing code but setting this to 0 (False) should + result in less work (i.e. it should be faster) but could cause problems + with other implementations that require strict checking. + + Default: 0 + +IP Variables +============ + +ip_local_port_range - 2 INTEGERS + Defines the local port range that is used by TCP and UDP to + choose the local port. The first number is the first, the + second the last local port number. + If possible, it is better these numbers have different parity + (one even and one odd value). + Must be greater than or equal to ip_unprivileged_port_start. + The default values are 32768 and 60999 respectively. + +ip_local_reserved_ports - list of comma separated ranges + Specify the ports which are reserved for known third-party + applications. These ports will not be used by automatic port + assignments (e.g. when calling connect() or bind() with port + number 0). Explicit port allocation behavior is unchanged. + + The format used for both input and output is a comma separated + list of ranges (e.g. "1,2-4,10-10" for ports 1, 2, 3, 4 and + 10). Writing to the file will clear all previously reserved + ports and update the current list with the one given in the + input. + + Note that ip_local_port_range and ip_local_reserved_ports + settings are independent and both are considered by the kernel + when determining which ports are available for automatic port + assignments. + + You can reserve ports which are not in the current + ip_local_port_range, e.g.:: + + $ cat /proc/sys/net/ipv4/ip_local_port_range + 32000 60999 + $ cat /proc/sys/net/ipv4/ip_local_reserved_ports + 8080,9148 + + although this is redundant. However such a setting is useful + if later the port range is changed to a value that will + include the reserved ports. Also keep in mind, that overlapping + of these ranges may affect probability of selecting ephemeral + ports which are right after block of reserved ports. + + Default: Empty + +ip_unprivileged_port_start - INTEGER + This is a per-namespace sysctl. It defines the first + unprivileged port in the network namespace. Privileged ports + require root or CAP_NET_BIND_SERVICE in order to bind to them. + To disable all privileged ports, set this to 0. They must not + overlap with the ip_local_port_range. + + Default: 1024 + +ip_nonlocal_bind - BOOLEAN + If set, allows processes to bind() to non-local IP addresses, + which can be quite useful - but may break some applications. + + Default: 0 + +ip_autobind_reuse - BOOLEAN + By default, bind() does not select the ports automatically even if + the new socket and all sockets bound to the port have SO_REUSEADDR. + ip_autobind_reuse allows bind() to reuse the port and this is useful + when you use bind()+connect(), but may break some applications. + The preferred solution is to use IP_BIND_ADDRESS_NO_PORT and this + option should only be set by experts. + Default: 0 + +ip_dynaddr - INTEGER + If set non-zero, enables support for dynamic addresses. + If set to a non-zero value larger than 1, a kernel log + message will be printed when dynamic address rewriting + occurs. + + Default: 0 + +ip_early_demux - BOOLEAN + Optimize input packet processing down to one demux for + certain kinds of local sockets. Currently we only do this + for established TCP and connected UDP sockets. + + It may add an additional cost for pure routing workloads that + reduces overall throughput, in such case you should disable it. + + Default: 1 + +ping_group_range - 2 INTEGERS + Restrict ICMP_PROTO datagram sockets to users in the group range. + The default is "1 0", meaning, that nobody (not even root) may + create ping sockets. Setting it to "100 100" would grant permissions + to the single group. "0 4294967294" would enable it for the world, "100 + 4294967294" would enable it for the users, but not daemons. + +tcp_early_demux - BOOLEAN + Enable early demux for established TCP sockets. + + Default: 1 + +udp_early_demux - BOOLEAN + Enable early demux for connected UDP sockets. Disable this if + your system could experience more unconnected load. + + Default: 1 + +icmp_echo_ignore_all - BOOLEAN + If set non-zero, then the kernel will ignore all ICMP ECHO + requests sent to it. + + Default: 0 + +icmp_echo_enable_probe - BOOLEAN + If set to one, then the kernel will respond to RFC 8335 PROBE + requests sent to it. + + Default: 0 + +icmp_echo_ignore_broadcasts - BOOLEAN + If set non-zero, then the kernel will ignore all ICMP ECHO and + TIMESTAMP requests sent to it via broadcast/multicast. + + Default: 1 + +icmp_ratelimit - INTEGER + Limit the maximal rates for sending ICMP packets whose type matches + icmp_ratemask (see below) to specific targets. + 0 to disable any limiting, + otherwise the minimal space between responses in milliseconds. + Note that another sysctl, icmp_msgs_per_sec limits the number + of ICMP packets sent on all targets. + + Default: 1000 + +icmp_msgs_per_sec - INTEGER + Limit maximal number of ICMP packets sent per second from this host. + Only messages whose type matches icmp_ratemask (see below) are + controlled by this limit. For security reasons, the precise count + of messages per second is randomized. + + Default: 1000 + +icmp_msgs_burst - INTEGER + icmp_msgs_per_sec controls number of ICMP packets sent per second, + while icmp_msgs_burst controls the burst size of these packets. + For security reasons, the precise burst size is randomized. + + Default: 50 + +icmp_ratemask - INTEGER + Mask made of ICMP types for which rates are being limited. + + Significant bits: IHGFEDCBA9876543210 + + Default mask: 0000001100000011000 (6168) + + Bit definitions (see include/linux/icmp.h): + + = ========================= + 0 Echo Reply + 3 Destination Unreachable [1]_ + 4 Source Quench [1]_ + 5 Redirect + 8 Echo Request + B Time Exceeded [1]_ + C Parameter Problem [1]_ + D Timestamp Request + E Timestamp Reply + F Info Request + G Info Reply + H Address Mask Request + I Address Mask Reply + = ========================= + + .. [1] These are rate limited by default (see default mask above) + +icmp_ignore_bogus_error_responses - BOOLEAN + Some routers violate RFC1122 by sending bogus responses to broadcast + frames. Such violations are normally logged via a kernel warning. + If this is set to TRUE, the kernel will not give such warnings, which + will avoid log file clutter. + + Default: 1 + +icmp_errors_use_inbound_ifaddr - BOOLEAN + + If zero, icmp error messages are sent with the primary address of + the exiting interface. + + If non-zero, the message will be sent with the primary address of + the interface that received the packet that caused the icmp error. + This is the behaviour many network administrators will expect from + a router. And it can make debugging complicated network layouts + much easier. + + Note that if no primary address exists for the interface selected, + then the primary address of the first non-loopback interface that + has one will be used regardless of this setting. + + Default: 0 + +igmp_max_memberships - INTEGER + Change the maximum number of multicast groups we can subscribe to. + Default: 20 + + Theoretical maximum value is bounded by having to send a membership + report in a single datagram (i.e. the report can't span multiple + datagrams, or risk confusing the switch and leaving groups you don't + intend to). + + The number of supported groups 'M' is bounded by the number of group + report entries you can fit into a single datagram of 65535 bytes. + + M = 65536-sizeof (ip header)/(sizeof(Group record)) + + Group records are variable length, with a minimum of 12 bytes. + So net.ipv4.igmp_max_memberships should not be set higher than: + + (65536-24) / 12 = 5459 + + The value 5459 assumes no IP header options, so in practice + this number may be lower. + +igmp_max_msf - INTEGER + Maximum number of addresses allowed in the source filter list for a + multicast group. + + Default: 10 + +igmp_qrv - INTEGER + Controls the IGMP query robustness variable (see RFC2236 8.1). + + Default: 2 (as specified by RFC2236 8.1) + + Minimum: 1 (as specified by RFC6636 4.5) + +force_igmp_version - INTEGER + - 0 - (default) No enforcement of a IGMP version, IGMPv1/v2 fallback + allowed. Will back to IGMPv3 mode again if all IGMPv1/v2 Querier + Present timer expires. + - 1 - Enforce to use IGMP version 1. Will also reply IGMPv1 report if + receive IGMPv2/v3 query. + - 2 - Enforce to use IGMP version 2. Will fallback to IGMPv1 if receive + IGMPv1 query message. Will reply report if receive IGMPv3 query. + - 3 - Enforce to use IGMP version 3. The same react with default 0. + + .. note:: + + this is not the same with force_mld_version because IGMPv3 RFC3376 + Security Considerations does not have clear description that we could + ignore other version messages completely as MLDv2 RFC3810. So make + this value as default 0 is recommended. + +``conf/interface/*`` + changes special settings per interface (where + interface" is the name of your network interface) + +``conf/all/*`` + is special, changes the settings for all interfaces + +log_martians - BOOLEAN + Log packets with impossible addresses to kernel log. + log_martians for the interface will be enabled if at least one of + conf/{all,interface}/log_martians is set to TRUE, + it will be disabled otherwise + +accept_redirects - BOOLEAN + Accept ICMP redirect messages. + accept_redirects for the interface will be enabled if: + + - both conf/{all,interface}/accept_redirects are TRUE in the case + forwarding for the interface is enabled + + or + + - at least one of conf/{all,interface}/accept_redirects is TRUE in the + case forwarding for the interface is disabled + + accept_redirects for the interface will be disabled otherwise + + default: + + - TRUE (host) + - FALSE (router) + +forwarding - BOOLEAN + Enable IP forwarding on this interface. This controls whether packets + received _on_ this interface can be forwarded. + +mc_forwarding - BOOLEAN + Do multicast routing. The kernel needs to be compiled with CONFIG_MROUTE + and a multicast routing daemon is required. + conf/all/mc_forwarding must also be set to TRUE to enable multicast + routing for the interface + +medium_id - INTEGER + Integer value used to differentiate the devices by the medium they + are attached to. Two devices can have different id values when + the broadcast packets are received only on one of them. + The default value 0 means that the device is the only interface + to its medium, value of -1 means that medium is not known. + + Currently, it is used to change the proxy_arp behavior: + the proxy_arp feature is enabled for packets forwarded between + two devices attached to different media. + +proxy_arp - BOOLEAN + Do proxy arp. + + proxy_arp for the interface will be enabled if at least one of + conf/{all,interface}/proxy_arp is set to TRUE, + it will be disabled otherwise + +proxy_arp_pvlan - BOOLEAN + Private VLAN proxy arp. + + Basically allow proxy arp replies back to the same interface + (from which the ARP request/solicitation was received). + + This is done to support (ethernet) switch features, like RFC + 3069, where the individual ports are NOT allowed to + communicate with each other, but they are allowed to talk to + the upstream router. As described in RFC 3069, it is possible + to allow these hosts to communicate through the upstream + router by proxy_arp'ing. Don't need to be used together with + proxy_arp. + + This technology is known by different names: + + In RFC 3069 it is called VLAN Aggregation. + Cisco and Allied Telesyn call it Private VLAN. + Hewlett-Packard call it Source-Port filtering or port-isolation. + Ericsson call it MAC-Forced Forwarding (RFC Draft). + +proxy_delay - INTEGER + Delay proxy response. + + Delay response to a neighbor solicitation when proxy_arp + or proxy_ndp is enabled. A random value between [0, proxy_delay) + will be chosen, setting to zero means reply with no delay. + Value in jiffies. Defaults to 80. + +shared_media - BOOLEAN + Send(router) or accept(host) RFC1620 shared media redirects. + Overrides secure_redirects. + + shared_media for the interface will be enabled if at least one of + conf/{all,interface}/shared_media is set to TRUE, + it will be disabled otherwise + + default TRUE + +secure_redirects - BOOLEAN + Accept ICMP redirect messages only to gateways listed in the + interface's current gateway list. Even if disabled, RFC1122 redirect + rules still apply. + + Overridden by shared_media. + + secure_redirects for the interface will be enabled if at least one of + conf/{all,interface}/secure_redirects is set to TRUE, + it will be disabled otherwise + + default TRUE + +send_redirects - BOOLEAN + Send redirects, if router. + + send_redirects for the interface will be enabled if at least one of + conf/{all,interface}/send_redirects is set to TRUE, + it will be disabled otherwise + + Default: TRUE + +bootp_relay - BOOLEAN + Accept packets with source address 0.b.c.d destined + not to this host as local ones. It is supposed, that + BOOTP relay daemon will catch and forward such packets. + conf/all/bootp_relay must also be set to TRUE to enable BOOTP relay + for the interface + + default FALSE + + Not Implemented Yet. + +accept_source_route - BOOLEAN + Accept packets with SRR option. + conf/all/accept_source_route must also be set to TRUE to accept packets + with SRR option on the interface + + default + + - TRUE (router) + - FALSE (host) + +accept_local - BOOLEAN + Accept packets with local source addresses. In combination with + suitable routing, this can be used to direct packets between two + local interfaces over the wire and have them accepted properly. + default FALSE + +route_localnet - BOOLEAN + Do not consider loopback addresses as martian source or destination + while routing. This enables the use of 127/8 for local routing purposes. + + default FALSE + +rp_filter - INTEGER + - 0 - No source validation. + - 1 - Strict mode as defined in RFC3704 Strict Reverse Path + Each incoming packet is tested against the FIB and if the interface + is not the best reverse path the packet check will fail. + By default failed packets are discarded. + - 2 - Loose mode as defined in RFC3704 Loose Reverse Path + Each incoming packet's source address is also tested against the FIB + and if the source address is not reachable via any interface + the packet check will fail. + + Current recommended practice in RFC3704 is to enable strict mode + to prevent IP spoofing from DDos attacks. If using asymmetric routing + or other complicated routing, then loose mode is recommended. + + The max value from conf/{all,interface}/rp_filter is used + when doing source validation on the {interface}. + + Default value is 0. Note that some distributions enable it + in startup scripts. + +src_valid_mark - BOOLEAN + - 0 - The fwmark of the packet is not included in reverse path + route lookup. This allows for asymmetric routing configurations + utilizing the fwmark in only one direction, e.g., transparent + proxying. + + - 1 - The fwmark of the packet is included in reverse path route + lookup. This permits rp_filter to function when the fwmark is + used for routing traffic in both directions. + + This setting also affects the utilization of fmwark when + performing source address selection for ICMP replies, or + determining addresses stored for the IPOPT_TS_TSANDADDR and + IPOPT_RR IP options. + + The max value from conf/{all,interface}/src_valid_mark is used. + + Default value is 0. + +arp_filter - BOOLEAN + - 1 - Allows you to have multiple network interfaces on the same + subnet, and have the ARPs for each interface be answered + based on whether or not the kernel would route a packet from + the ARP'd IP out that interface (therefore you must use source + based routing for this to work). In other words it allows control + of which cards (usually 1) will respond to an arp request. + + - 0 - (default) The kernel can respond to arp requests with addresses + from other interfaces. This may seem wrong but it usually makes + sense, because it increases the chance of successful communication. + IP addresses are owned by the complete host on Linux, not by + particular interfaces. Only for more complex setups like load- + balancing, does this behaviour cause problems. + + arp_filter for the interface will be enabled if at least one of + conf/{all,interface}/arp_filter is set to TRUE, + it will be disabled otherwise + +arp_announce - INTEGER + Define different restriction levels for announcing the local + source IP address from IP packets in ARP requests sent on + interface: + + - 0 - (default) Use any local address, configured on any interface + - 1 - Try to avoid local addresses that are not in the target's + subnet for this interface. This mode is useful when target + hosts reachable via this interface require the source IP + address in ARP requests to be part of their logical network + configured on the receiving interface. When we generate the + request we will check all our subnets that include the + target IP and will preserve the source address if it is from + such subnet. If there is no such subnet we select source + address according to the rules for level 2. + - 2 - Always use the best local address for this target. + In this mode we ignore the source address in the IP packet + and try to select local address that we prefer for talks with + the target host. Such local address is selected by looking + for primary IP addresses on all our subnets on the outgoing + interface that include the target IP address. If no suitable + local address is found we select the first local address + we have on the outgoing interface or on all other interfaces, + with the hope we will receive reply for our request and + even sometimes no matter the source IP address we announce. + + The max value from conf/{all,interface}/arp_announce is used. + + Increasing the restriction level gives more chance for + receiving answer from the resolved target while decreasing + the level announces more valid sender's information. + +arp_ignore - INTEGER + Define different modes for sending replies in response to + received ARP requests that resolve local target IP addresses: + + - 0 - (default): reply for any local target IP address, configured + on any interface + - 1 - reply only if the target IP address is local address + configured on the incoming interface + - 2 - reply only if the target IP address is local address + configured on the incoming interface and both with the + sender's IP address are part from same subnet on this interface + - 3 - do not reply for local addresses configured with scope host, + only resolutions for global and link addresses are replied + - 4-7 - reserved + - 8 - do not reply for all local addresses + + The max value from conf/{all,interface}/arp_ignore is used + when ARP request is received on the {interface} + +arp_notify - BOOLEAN + Define mode for notification of address and device changes. + + == ========================================================== + 0 (default): do nothing + 1 Generate gratuitous arp requests when device is brought up + or hardware address changes. + == ========================================================== + +arp_accept - INTEGER + Define behavior for accepting gratuitous ARP (garp) frames from devices + that are not already present in the ARP table: + + - 0 - don't create new entries in the ARP table + - 1 - create new entries in the ARP table + - 2 - create new entries only if the source IP address is in the same + subnet as an address configured on the interface that received the + garp message. + + Both replies and requests type gratuitous arp will trigger the + ARP table to be updated, if this setting is on. + + If the ARP table already contains the IP address of the + gratuitous arp frame, the arp table will be updated regardless + if this setting is on or off. + +arp_evict_nocarrier - BOOLEAN + Clears the ARP cache on NOCARRIER events. This option is important for + wireless devices where the ARP cache should not be cleared when roaming + between access points on the same network. In most cases this should + remain as the default (1). + + - 1 - (default): Clear the ARP cache on NOCARRIER events + - 0 - Do not clear ARP cache on NOCARRIER events + +mcast_solicit - INTEGER + The maximum number of multicast probes in INCOMPLETE state, + when the associated hardware address is unknown. Defaults + to 3. + +ucast_solicit - INTEGER + The maximum number of unicast probes in PROBE state, when + the hardware address is being reconfirmed. Defaults to 3. + +app_solicit - INTEGER + The maximum number of probes to send to the user space ARP daemon + via netlink before dropping back to multicast probes (see + mcast_resolicit). Defaults to 0. + +mcast_resolicit - INTEGER + The maximum number of multicast probes after unicast and + app probes in PROBE state. Defaults to 0. + +disable_policy - BOOLEAN + Disable IPSEC policy (SPD) for this interface + +disable_xfrm - BOOLEAN + Disable IPSEC encryption on this interface, whatever the policy + +igmpv2_unsolicited_report_interval - INTEGER + The interval in milliseconds in which the next unsolicited + IGMPv1 or IGMPv2 report retransmit will take place. + + Default: 10000 (10 seconds) + +igmpv3_unsolicited_report_interval - INTEGER + The interval in milliseconds in which the next unsolicited + IGMPv3 report retransmit will take place. + + Default: 1000 (1 seconds) + +ignore_routes_with_linkdown - BOOLEAN + Ignore routes whose link is down when performing a FIB lookup. + +promote_secondaries - BOOLEAN + When a primary IP address is removed from this interface + promote a corresponding secondary IP address instead of + removing all the corresponding secondary IP addresses. + +drop_unicast_in_l2_multicast - BOOLEAN + Drop any unicast IP packets that are received in link-layer + multicast (or broadcast) frames. + + This behavior (for multicast) is actually a SHOULD in RFC + 1122, but is disabled by default for compatibility reasons. + + Default: off (0) + +drop_gratuitous_arp - BOOLEAN + Drop all gratuitous ARP frames, for example if there's a known + good ARP proxy on the network and such frames need not be used + (or in the case of 802.11, must not be used to prevent attacks.) + + Default: off (0) + + +tag - INTEGER + Allows you to write a number, which can be used as required. + + Default value is 0. + +xfrm4_gc_thresh - INTEGER + (Obsolete since linux-4.14) + The threshold at which we will start garbage collecting for IPv4 + destination cache entries. At twice this value the system will + refuse new allocations. + +igmp_link_local_mcast_reports - BOOLEAN + Enable IGMP reports for link local multicast groups in the + 224.0.0.X range. + + Default TRUE + +Alexey Kuznetsov. +kuznet@ms2.inr.ac.ru + +Updated by: + +- Andi Kleen + ak@muc.de +- Nicolas Delon + delon.nicolas@wanadoo.fr + + + + +/proc/sys/net/ipv6/* Variables +============================== + +IPv6 has no global variables such as tcp_*. tcp_* settings under ipv4/ also +apply to IPv6 [XXX?]. + +bindv6only - BOOLEAN + Default value for IPV6_V6ONLY socket option, + which restricts use of the IPv6 socket to IPv6 communication + only. + + - TRUE: disable IPv4-mapped address feature + - FALSE: enable IPv4-mapped address feature + + Default: FALSE (as specified in RFC3493) + +flowlabel_consistency - BOOLEAN + Protect the consistency (and unicity) of flow label. + You have to disable it to use IPV6_FL_F_REFLECT flag on the + flow label manager. + + - TRUE: enabled + - FALSE: disabled + + Default: TRUE + +auto_flowlabels - INTEGER + Automatically generate flow labels based on a flow hash of the + packet. This allows intermediate devices, such as routers, to + identify packet flows for mechanisms like Equal Cost Multipath + Routing (see RFC 6438). + + = =========================================================== + 0 automatic flow labels are completely disabled + 1 automatic flow labels are enabled by default, they can be + disabled on a per socket basis using the IPV6_AUTOFLOWLABEL + socket option + 2 automatic flow labels are allowed, they may be enabled on a + per socket basis using the IPV6_AUTOFLOWLABEL socket option + 3 automatic flow labels are enabled and enforced, they cannot + be disabled by the socket option + = =========================================================== + + Default: 1 + +flowlabel_state_ranges - BOOLEAN + Split the flow label number space into two ranges. 0-0x7FFFF is + reserved for the IPv6 flow manager facility, 0x80000-0xFFFFF + is reserved for stateless flow labels as described in RFC6437. + + - TRUE: enabled + - FALSE: disabled + + Default: true + +flowlabel_reflect - INTEGER + Control flow label reflection. Needed for Path MTU + Discovery to work with Equal Cost Multipath Routing in anycast + environments. See RFC 7690 and: + https://tools.ietf.org/html/draft-wang-6man-flow-label-reflection-01 + + This is a bitmask. + + - 1: enabled for established flows + + Note that this prevents automatic flowlabel changes, as done + in "tcp: change IPv6 flow-label upon receiving spurious retransmission" + and "tcp: Change txhash on every SYN and RTO retransmit" + + - 2: enabled for TCP RESET packets (no active listener) + If set, a RST packet sent in response to a SYN packet on a closed + port will reflect the incoming flow label. + + - 4: enabled for ICMPv6 echo reply messages. + + Default: 0 + +fib_multipath_hash_policy - INTEGER + Controls which hash policy to use for multipath routes. + + Default: 0 (Layer 3) + + Possible values: + + - 0 - Layer 3 (source and destination addresses plus flow label) + - 1 - Layer 4 (standard 5-tuple) + - 2 - Layer 3 or inner Layer 3 if present + - 3 - Custom multipath hash. Fields used for multipath hash calculation + are determined by fib_multipath_hash_fields sysctl + +fib_multipath_hash_fields - UNSIGNED INTEGER + When fib_multipath_hash_policy is set to 3 (custom multipath hash), the + fields used for multipath hash calculation are determined by this + sysctl. + + This value is a bitmask which enables various fields for multipath hash + calculation. + + Possible fields are: + + ====== ============================ + 0x0001 Source IP address + 0x0002 Destination IP address + 0x0004 IP protocol + 0x0008 Flow Label + 0x0010 Source port + 0x0020 Destination port + 0x0040 Inner source IP address + 0x0080 Inner destination IP address + 0x0100 Inner IP protocol + 0x0200 Inner Flow Label + 0x0400 Inner source port + 0x0800 Inner destination port + ====== ============================ + + Default: 0x0007 (source IP, destination IP and IP protocol) + +anycast_src_echo_reply - BOOLEAN + Controls the use of anycast addresses as source addresses for ICMPv6 + echo reply + + - TRUE: enabled + - FALSE: disabled + + Default: FALSE + +idgen_delay - INTEGER + Controls the delay in seconds after which time to retry + privacy stable address generation if a DAD conflict is + detected. + + Default: 1 (as specified in RFC7217) + +idgen_retries - INTEGER + Controls the number of retries to generate a stable privacy + address if a DAD conflict is detected. + + Default: 3 (as specified in RFC7217) + +mld_qrv - INTEGER + Controls the MLD query robustness variable (see RFC3810 9.1). + + Default: 2 (as specified by RFC3810 9.1) + + Minimum: 1 (as specified by RFC6636 4.5) + +max_dst_opts_number - INTEGER + Maximum number of non-padding TLVs allowed in a Destination + options extension header. If this value is less than zero + then unknown options are disallowed and the number of known + TLVs allowed is the absolute value of this number. + + Default: 8 + +max_hbh_opts_number - INTEGER + Maximum number of non-padding TLVs allowed in a Hop-by-Hop + options extension header. If this value is less than zero + then unknown options are disallowed and the number of known + TLVs allowed is the absolute value of this number. + + Default: 8 + +max_dst_opts_length - INTEGER + Maximum length allowed for a Destination options extension + header. + + Default: INT_MAX (unlimited) + +max_hbh_length - INTEGER + Maximum length allowed for a Hop-by-Hop options extension + header. + + Default: INT_MAX (unlimited) + +skip_notify_on_dev_down - BOOLEAN + Controls whether an RTM_DELROUTE message is generated for routes + removed when a device is taken down or deleted. IPv4 does not + generate this message; IPv6 does by default. Setting this sysctl + to true skips the message, making IPv4 and IPv6 on par in relying + on userspace caches to track link events and evict routes. + + Default: false (generate message) + +nexthop_compat_mode - BOOLEAN + New nexthop API provides a means for managing nexthops independent of + prefixes. Backwards compatibility with old route format is enabled by + default which means route dumps and notifications contain the new + nexthop attribute but also the full, expanded nexthop definition. + Further, updates or deletes of a nexthop configuration generate route + notifications for each fib entry using the nexthop. Once a system + understands the new API, this sysctl can be disabled to achieve full + performance benefits of the new API by disabling the nexthop expansion + and extraneous notifications. + Default: true (backward compat mode) + +fib_notify_on_flag_change - INTEGER + Whether to emit RTM_NEWROUTE notifications whenever RTM_F_OFFLOAD/ + RTM_F_TRAP/RTM_F_OFFLOAD_FAILED flags are changed. + + After installing a route to the kernel, user space receives an + acknowledgment, which means the route was installed in the kernel, + but not necessarily in hardware. + It is also possible for a route already installed in hardware to change + its action and therefore its flags. For example, a host route that is + trapping packets can be "promoted" to perform decapsulation following + the installation of an IPinIP/VXLAN tunnel. + The notifications will indicate to user-space the state of the route. + + Default: 0 (Do not emit notifications.) + + Possible values: + + - 0 - Do not emit notifications. + - 1 - Emit notifications. + - 2 - Emit notifications only for RTM_F_OFFLOAD_FAILED flag change. + +ioam6_id - INTEGER + Define the IOAM id of this node. Uses only 24 bits out of 32 in total. + + Min: 0 + Max: 0xFFFFFF + + Default: 0xFFFFFF + +ioam6_id_wide - LONG INTEGER + Define the wide IOAM id of this node. Uses only 56 bits out of 64 in + total. Can be different from ioam6_id. + + Min: 0 + Max: 0xFFFFFFFFFFFFFF + + Default: 0xFFFFFFFFFFFFFF + +IPv6 Fragmentation: + +ip6frag_high_thresh - INTEGER + Maximum memory used to reassemble IPv6 fragments. When + ip6frag_high_thresh bytes of memory is allocated for this purpose, + the fragment handler will toss packets until ip6frag_low_thresh + is reached. + +ip6frag_low_thresh - INTEGER + See ip6frag_high_thresh + +ip6frag_time - INTEGER + Time in seconds to keep an IPv6 fragment in memory. + +``conf/default/*``: + Change the interface-specific default settings. + + These settings would be used during creating new interfaces. + + +``conf/all/*``: + Change all the interface-specific settings. + + [XXX: Other special features than forwarding?] + +conf/all/disable_ipv6 - BOOLEAN + Changing this value is same as changing ``conf/default/disable_ipv6`` + setting and also all per-interface ``disable_ipv6`` settings to the same + value. + + Reading this value does not have any particular meaning. It does not say + whether IPv6 support is enabled or disabled. Returned value can be 1 + also in the case when some interface has ``disable_ipv6`` set to 0 and + has configured IPv6 addresses. + +conf/all/forwarding - BOOLEAN + Enable global IPv6 forwarding between all interfaces. + + IPv4 and IPv6 work differently here; e.g. netfilter must be used + to control which interfaces may forward packets and which not. + + This also sets all interfaces' Host/Router setting + 'forwarding' to the specified value. See below for details. + + This referred to as global forwarding. + +proxy_ndp - BOOLEAN + Do proxy ndp. + +fwmark_reflect - BOOLEAN + Controls the fwmark of kernel-generated IPv6 reply packets that are not + associated with a socket for example, TCP RSTs or ICMPv6 echo replies). + If unset, these packets have a fwmark of zero. If set, they have the + fwmark of the packet they are replying to. + + Default: 0 + +``conf/interface/*``: + Change special settings per interface. + + The functional behaviour for certain settings is different + depending on whether local forwarding is enabled or not. + +accept_ra - INTEGER + Accept Router Advertisements; autoconfigure using them. + + It also determines whether or not to transmit Router + Solicitations. If and only if the functional setting is to + accept Router Advertisements, Router Solicitations will be + transmitted. + + Possible values are: + + == =========================================================== + 0 Do not accept Router Advertisements. + 1 Accept Router Advertisements if forwarding is disabled. + 2 Overrule forwarding behaviour. Accept Router Advertisements + even if forwarding is enabled. + == =========================================================== + + Functional default: + + - enabled if local forwarding is disabled. + - disabled if local forwarding is enabled. + +accept_ra_defrtr - BOOLEAN + Learn default router in Router Advertisement. + + Functional default: + + - enabled if accept_ra is enabled. + - disabled if accept_ra is disabled. + +ra_defrtr_metric - UNSIGNED INTEGER + Route metric for default route learned in Router Advertisement. This value + will be assigned as metric for the default route learned via IPv6 Router + Advertisement. Takes affect only if accept_ra_defrtr is enabled. + + Possible values: + 1 to 0xFFFFFFFF + + Default: IP6_RT_PRIO_USER i.e. 1024. + +accept_ra_from_local - BOOLEAN + Accept RA with source-address that is found on local machine + if the RA is otherwise proper and able to be accepted. + + Default is to NOT accept these as it may be an un-intended + network loop. + + Functional default: + + - enabled if accept_ra_from_local is enabled + on a specific interface. + - disabled if accept_ra_from_local is disabled + on a specific interface. + +accept_ra_min_hop_limit - INTEGER + Minimum hop limit Information in Router Advertisement. + + Hop limit Information in Router Advertisement less than this + variable shall be ignored. + + Default: 1 + +accept_ra_min_lft - INTEGER + Minimum acceptable lifetime value in Router Advertisement. + + RA sections with a lifetime less than this value shall be + ignored. Zero lifetimes stay unaffected. + + Default: 0 + +accept_ra_pinfo - BOOLEAN + Learn Prefix Information in Router Advertisement. + + Functional default: + + - enabled if accept_ra is enabled. + - disabled if accept_ra is disabled. + +accept_ra_rt_info_min_plen - INTEGER + Minimum prefix length of Route Information in RA. + + Route Information w/ prefix smaller than this variable shall + be ignored. + + Functional default: + + * 0 if accept_ra_rtr_pref is enabled. + * -1 if accept_ra_rtr_pref is disabled. + +accept_ra_rt_info_max_plen - INTEGER + Maximum prefix length of Route Information in RA. + + Route Information w/ prefix larger than this variable shall + be ignored. + + Functional default: + + * 0 if accept_ra_rtr_pref is enabled. + * -1 if accept_ra_rtr_pref is disabled. + +accept_ra_rtr_pref - BOOLEAN + Accept Router Preference in RA. + + Functional default: + + - enabled if accept_ra is enabled. + - disabled if accept_ra is disabled. + +accept_ra_mtu - BOOLEAN + Apply the MTU value specified in RA option 5 (RFC4861). If + disabled, the MTU specified in the RA will be ignored. + + Functional default: + + - enabled if accept_ra is enabled. + - disabled if accept_ra is disabled. + +accept_redirects - BOOLEAN + Accept Redirects. + + Functional default: + + - enabled if local forwarding is disabled. + - disabled if local forwarding is enabled. + +accept_source_route - INTEGER + Accept source routing (routing extension header). + + - >= 0: Accept only routing header type 2. + - < 0: Do not accept routing header. + + Default: 0 + +autoconf - BOOLEAN + Autoconfigure addresses using Prefix Information in Router + Advertisements. + + Functional default: + + - enabled if accept_ra_pinfo is enabled. + - disabled if accept_ra_pinfo is disabled. + +dad_transmits - INTEGER + The amount of Duplicate Address Detection probes to send. + + Default: 1 + +forwarding - INTEGER + Configure interface-specific Host/Router behaviour. + + .. note:: + + It is recommended to have the same setting on all + interfaces; mixed router/host scenarios are rather uncommon. + + Possible values are: + + - 0 Forwarding disabled + - 1 Forwarding enabled + + **FALSE (0)**: + + By default, Host behaviour is assumed. This means: + + 1. IsRouter flag is not set in Neighbour Advertisements. + 2. If accept_ra is TRUE (default), transmit Router + Solicitations. + 3. If accept_ra is TRUE (default), accept Router + Advertisements (and do autoconfiguration). + 4. If accept_redirects is TRUE (default), accept Redirects. + + **TRUE (1)**: + + If local forwarding is enabled, Router behaviour is assumed. + This means exactly the reverse from the above: + + 1. IsRouter flag is set in Neighbour Advertisements. + 2. Router Solicitations are not sent unless accept_ra is 2. + 3. Router Advertisements are ignored unless accept_ra is 2. + 4. Redirects are ignored. + + Default: 0 (disabled) if global forwarding is disabled (default), + otherwise 1 (enabled). + +hop_limit - INTEGER + Default Hop Limit to set. + + Default: 64 + +mtu - INTEGER + Default Maximum Transfer Unit + + Default: 1280 (IPv6 required minimum) + +ip_nonlocal_bind - BOOLEAN + If set, allows processes to bind() to non-local IPv6 addresses, + which can be quite useful - but may break some applications. + + Default: 0 + +router_probe_interval - INTEGER + Minimum interval (in seconds) between Router Probing described + in RFC4191. + + Default: 60 + +router_solicitation_delay - INTEGER + Number of seconds to wait after interface is brought up + before sending Router Solicitations. + + Default: 1 + +router_solicitation_interval - INTEGER + Number of seconds to wait between Router Solicitations. + + Default: 4 + +router_solicitations - INTEGER + Number of Router Solicitations to send until assuming no + routers are present. + + Default: 3 + +use_oif_addrs_only - BOOLEAN + When enabled, the candidate source addresses for destinations + routed via this interface are restricted to the set of addresses + configured on this interface (vis. RFC 6724, section 4). + + Default: false + +use_tempaddr - INTEGER + Preference for Privacy Extensions (RFC3041). + + * <= 0 : disable Privacy Extensions + * == 1 : enable Privacy Extensions, but prefer public + addresses over temporary addresses. + * > 1 : enable Privacy Extensions and prefer temporary + addresses over public addresses. + + Default: + + * 0 (for most devices) + * -1 (for point-to-point devices and loopback devices) + +temp_valid_lft - INTEGER + valid lifetime (in seconds) for temporary addresses. + + Default: 172800 (2 days) + +temp_prefered_lft - INTEGER + Preferred lifetime (in seconds) for temporary addresses. + + Default: 86400 (1 day) + +keep_addr_on_down - INTEGER + Keep all IPv6 addresses on an interface down event. If set static + global addresses with no expiration time are not flushed. + + * >0 : enabled + * 0 : system default + * <0 : disabled + + Default: 0 (addresses are removed) + +max_desync_factor - INTEGER + Maximum value for DESYNC_FACTOR, which is a random value + that ensures that clients don't synchronize with each + other and generate new addresses at exactly the same time. + value is in seconds. + + Default: 600 + +regen_max_retry - INTEGER + Number of attempts before give up attempting to generate + valid temporary addresses. + + Default: 5 + +max_addresses - INTEGER + Maximum number of autoconfigured addresses per interface. Setting + to zero disables the limitation. It is not recommended to set this + value too large (or to zero) because it would be an easy way to + crash the kernel by allowing too many addresses to be created. + + Default: 16 + +disable_ipv6 - BOOLEAN + Disable IPv6 operation. If accept_dad is set to 2, this value + will be dynamically set to TRUE if DAD fails for the link-local + address. + + Default: FALSE (enable IPv6 operation) + + When this value is changed from 1 to 0 (IPv6 is being enabled), + it will dynamically create a link-local address on the given + interface and start Duplicate Address Detection, if necessary. + + When this value is changed from 0 to 1 (IPv6 is being disabled), + it will dynamically delete all addresses and routes on the given + interface. From now on it will not possible to add addresses/routes + to the selected interface. + +accept_dad - INTEGER + Whether to accept DAD (Duplicate Address Detection). + + == ============================================================== + 0 Disable DAD + 1 Enable DAD (default) + 2 Enable DAD, and disable IPv6 operation if MAC-based duplicate + link-local address has been found. + == ============================================================== + + DAD operation and mode on a given interface will be selected according + to the maximum value of conf/{all,interface}/accept_dad. + +force_tllao - BOOLEAN + Enable sending the target link-layer address option even when + responding to a unicast neighbor solicitation. + + Default: FALSE + + Quoting from RFC 2461, section 4.4, Target link-layer address: + + "The option MUST be included for multicast solicitations in order to + avoid infinite Neighbor Solicitation "recursion" when the peer node + does not have a cache entry to return a Neighbor Advertisements + message. When responding to unicast solicitations, the option can be + omitted since the sender of the solicitation has the correct link- + layer address; otherwise it would not have be able to send the unicast + solicitation in the first place. However, including the link-layer + address in this case adds little overhead and eliminates a potential + race condition where the sender deletes the cached link-layer address + prior to receiving a response to a previous solicitation." + +ndisc_notify - BOOLEAN + Define mode for notification of address and device changes. + + * 0 - (default): do nothing + * 1 - Generate unsolicited neighbour advertisements when device is brought + up or hardware address changes. + +ndisc_tclass - INTEGER + The IPv6 Traffic Class to use by default when sending IPv6 Neighbor + Discovery (Router Solicitation, Router Advertisement, Neighbor + Solicitation, Neighbor Advertisement, Redirect) messages. + These 8 bits can be interpreted as 6 high order bits holding the DSCP + value and 2 low order bits representing ECN (which you probably want + to leave cleared). + + * 0 - (default) + +ndisc_evict_nocarrier - BOOLEAN + Clears the neighbor discovery table on NOCARRIER events. This option is + important for wireless devices where the neighbor discovery cache should + not be cleared when roaming between access points on the same network. + In most cases this should remain as the default (1). + + - 1 - (default): Clear neighbor discover cache on NOCARRIER events. + - 0 - Do not clear neighbor discovery cache on NOCARRIER events. + +mldv1_unsolicited_report_interval - INTEGER + The interval in milliseconds in which the next unsolicited + MLDv1 report retransmit will take place. + + Default: 10000 (10 seconds) + +mldv2_unsolicited_report_interval - INTEGER + The interval in milliseconds in which the next unsolicited + MLDv2 report retransmit will take place. + + Default: 1000 (1 second) + +force_mld_version - INTEGER + * 0 - (default) No enforcement of a MLD version, MLDv1 fallback allowed + * 1 - Enforce to use MLD version 1 + * 2 - Enforce to use MLD version 2 + +suppress_frag_ndisc - INTEGER + Control RFC 6980 (Security Implications of IPv6 Fragmentation + with IPv6 Neighbor Discovery) behavior: + + * 1 - (default) discard fragmented neighbor discovery packets + * 0 - allow fragmented neighbor discovery packets + +optimistic_dad - BOOLEAN + Whether to perform Optimistic Duplicate Address Detection (RFC 4429). + + * 0: disabled (default) + * 1: enabled + + Optimistic Duplicate Address Detection for the interface will be enabled + if at least one of conf/{all,interface}/optimistic_dad is set to 1, + it will be disabled otherwise. + +use_optimistic - BOOLEAN + If enabled, do not classify optimistic addresses as deprecated during + source address selection. Preferred addresses will still be chosen + before optimistic addresses, subject to other ranking in the source + address selection algorithm. + + * 0: disabled (default) + * 1: enabled + + This will be enabled if at least one of + conf/{all,interface}/use_optimistic is set to 1, disabled otherwise. + +stable_secret - IPv6 address + This IPv6 address will be used as a secret to generate IPv6 + addresses for link-local addresses and autoconfigured + ones. All addresses generated after setting this secret will + be stable privacy ones by default. This can be changed via the + addrgenmode ip-link. conf/default/stable_secret is used as the + secret for the namespace, the interface specific ones can + overwrite that. Writes to conf/all/stable_secret are refused. + + It is recommended to generate this secret during installation + of a system and keep it stable after that. + + By default the stable secret is unset. + +addr_gen_mode - INTEGER + Defines how link-local and autoconf addresses are generated. + + = ================================================================= + 0 generate address based on EUI64 (default) + 1 do no generate a link-local address, use EUI64 for addresses + generated from autoconf + 2 generate stable privacy addresses, using the secret from + stable_secret (RFC7217) + 3 generate stable privacy addresses, using a random secret if unset + = ================================================================= + +drop_unicast_in_l2_multicast - BOOLEAN + Drop any unicast IPv6 packets that are received in link-layer + multicast (or broadcast) frames. + + By default this is turned off. + +drop_unsolicited_na - BOOLEAN + Drop all unsolicited neighbor advertisements, for example if there's + a known good NA proxy on the network and such frames need not be used + (or in the case of 802.11, must not be used to prevent attacks.) + + By default this is turned off. + +accept_untracked_na - INTEGER + Define behavior for accepting neighbor advertisements from devices that + are absent in the neighbor cache: + + - 0 - (default) Do not accept unsolicited and untracked neighbor + advertisements. + + - 1 - Add a new neighbor cache entry in STALE state for routers on + receiving a neighbor advertisement (either solicited or unsolicited) + with target link-layer address option specified if no neighbor entry + is already present for the advertised IPv6 address. Without this knob, + NAs received for untracked addresses (absent in neighbor cache) are + silently ignored. + + This is as per router-side behavior documented in RFC9131. + + This has lower precedence than drop_unsolicited_na. + + This will optimize the return path for the initial off-link + communication that is initiated by a directly connected host, by + ensuring that the first-hop router which turns on this setting doesn't + have to buffer the initial return packets to do neighbor-solicitation. + The prerequisite is that the host is configured to send unsolicited + neighbor advertisements on interface bringup. This setting should be + used in conjunction with the ndisc_notify setting on the host to + satisfy this prerequisite. + + - 2 - Extend option (1) to add a new neighbor cache entry only if the + source IP address is in the same subnet as an address configured on + the interface that received the neighbor advertisement. + +enhanced_dad - BOOLEAN + Include a nonce option in the IPv6 neighbor solicitation messages used for + duplicate address detection per RFC7527. A received DAD NS will only signal + a duplicate address if the nonce is different. This avoids any false + detection of duplicates due to loopback of the NS messages that we send. + The nonce option will be sent on an interface unless both of + conf/{all,interface}/enhanced_dad are set to FALSE. + + Default: TRUE + +``icmp/*``: +=========== + +ratelimit - INTEGER + Limit the maximal rates for sending ICMPv6 messages. + + 0 to disable any limiting, + otherwise the minimal space between responses in milliseconds. + + Default: 1000 + +ratemask - list of comma separated ranges + For ICMPv6 message types matching the ranges in the ratemask, limit + the sending of the message according to ratelimit parameter. + + The format used for both input and output is a comma separated + list of ranges (e.g. "0-127,129" for ICMPv6 message type 0 to 127 and + 129). Writing to the file will clear all previous ranges of ICMPv6 + message types and update the current list with the input. + + Refer to: https://www.iana.org/assignments/icmpv6-parameters/icmpv6-parameters.xhtml + for numerical values of ICMPv6 message types, e.g. echo request is 128 + and echo reply is 129. + + Default: 0-1,3-127 (rate limit ICMPv6 errors except Packet Too Big) + +echo_ignore_all - BOOLEAN + If set non-zero, then the kernel will ignore all ICMP ECHO + requests sent to it over the IPv6 protocol. + + Default: 0 + +echo_ignore_multicast - BOOLEAN + If set non-zero, then the kernel will ignore all ICMP ECHO + requests sent to it over the IPv6 protocol via multicast. + + Default: 0 + +echo_ignore_anycast - BOOLEAN + If set non-zero, then the kernel will ignore all ICMP ECHO + requests sent to it over the IPv6 protocol destined to anycast address. + + Default: 0 + +error_anycast_as_unicast - BOOLEAN + If set to 1, then the kernel will respond with ICMP Errors + resulting from requests sent to it over the IPv6 protocol destined + to anycast address essentially treating anycast as unicast. + + Default: 0 + +xfrm6_gc_thresh - INTEGER + (Obsolete since linux-4.14) + The threshold at which we will start garbage collecting for IPv6 + destination cache entries. At twice this value the system will + refuse new allocations. + + +IPv6 Update by: +Pekka Savola <pekkas@netcore.fi> +YOSHIFUJI Hideaki / USAGI Project <yoshfuji@linux-ipv6.org> + + +/proc/sys/net/bridge/* Variables: +================================= + +bridge-nf-call-arptables - BOOLEAN + - 1 : pass bridged ARP traffic to arptables' FORWARD chain. + - 0 : disable this. + + Default: 1 + +bridge-nf-call-iptables - BOOLEAN + - 1 : pass bridged IPv4 traffic to iptables' chains. + - 0 : disable this. + + Default: 1 + +bridge-nf-call-ip6tables - BOOLEAN + - 1 : pass bridged IPv6 traffic to ip6tables' chains. + - 0 : disable this. + + Default: 1 + +bridge-nf-filter-vlan-tagged - BOOLEAN + - 1 : pass bridged vlan-tagged ARP/IP/IPv6 traffic to {arp,ip,ip6}tables. + - 0 : disable this. + + Default: 0 + +bridge-nf-filter-pppoe-tagged - BOOLEAN + - 1 : pass bridged pppoe-tagged IP/IPv6 traffic to {ip,ip6}tables. + - 0 : disable this. + + Default: 0 + +bridge-nf-pass-vlan-input-dev - BOOLEAN + - 1: if bridge-nf-filter-vlan-tagged is enabled, try to find a vlan + interface on the bridge and set the netfilter input device to the + vlan. This allows use of e.g. "iptables -i br0.1" and makes the + REDIRECT target work with vlan-on-top-of-bridge interfaces. When no + matching vlan interface is found, or this switch is off, the input + device is set to the bridge interface. + + - 0: disable bridge netfilter vlan interface lookup. + + Default: 0 + +``proc/sys/net/sctp/*`` Variables: +================================== + +addip_enable - BOOLEAN + Enable or disable extension of Dynamic Address Reconfiguration + (ADD-IP) functionality specified in RFC5061. This extension provides + the ability to dynamically add and remove new addresses for the SCTP + associations. + + 1: Enable extension. + + 0: Disable extension. + + Default: 0 + +pf_enable - INTEGER + Enable or disable pf (pf is short for potentially failed) state. A value + of pf_retrans > path_max_retrans also disables pf state. That is, one of + both pf_enable and pf_retrans > path_max_retrans can disable pf state. + Since pf_retrans and path_max_retrans can be changed by userspace + application, sometimes user expects to disable pf state by the value of + pf_retrans > path_max_retrans, but occasionally the value of pf_retrans + or path_max_retrans is changed by the user application, this pf state is + enabled. As such, it is necessary to add this to dynamically enable + and disable pf state. See: + https://datatracker.ietf.org/doc/draft-ietf-tsvwg-sctp-failover for + details. + + 1: Enable pf. + + 0: Disable pf. + + Default: 1 + +pf_expose - INTEGER + Unset or enable/disable pf (pf is short for potentially failed) state + exposure. Applications can control the exposure of the PF path state + in the SCTP_PEER_ADDR_CHANGE event and the SCTP_GET_PEER_ADDR_INFO + sockopt. When it's unset, no SCTP_PEER_ADDR_CHANGE event with + SCTP_ADDR_PF state will be sent and a SCTP_PF-state transport info + can be got via SCTP_GET_PEER_ADDR_INFO sockopt; When it's enabled, + a SCTP_PEER_ADDR_CHANGE event will be sent for a transport becoming + SCTP_PF state and a SCTP_PF-state transport info can be got via + SCTP_GET_PEER_ADDR_INFO sockopt; When it's disabled, no + SCTP_PEER_ADDR_CHANGE event will be sent and it returns -EACCES when + trying to get a SCTP_PF-state transport info via SCTP_GET_PEER_ADDR_INFO + sockopt. + + 0: Unset pf state exposure, Compatible with old applications. + + 1: Disable pf state exposure. + + 2: Enable pf state exposure. + + Default: 0 + +addip_noauth_enable - BOOLEAN + Dynamic Address Reconfiguration (ADD-IP) requires the use of + authentication to protect the operations of adding or removing new + addresses. This requirement is mandated so that unauthorized hosts + would not be able to hijack associations. However, older + implementations may not have implemented this requirement while + allowing the ADD-IP extension. For reasons of interoperability, + we provide this variable to control the enforcement of the + authentication requirement. + + == =============================================================== + 1 Allow ADD-IP extension to be used without authentication. This + should only be set in a closed environment for interoperability + with older implementations. + + 0 Enforce the authentication requirement + == =============================================================== + + Default: 0 + +auth_enable - BOOLEAN + Enable or disable Authenticated Chunks extension. This extension + provides the ability to send and receive authenticated chunks and is + required for secure operation of Dynamic Address Reconfiguration + (ADD-IP) extension. + + - 1: Enable this extension. + - 0: Disable this extension. + + Default: 0 + +prsctp_enable - BOOLEAN + Enable or disable the Partial Reliability extension (RFC3758) which + is used to notify peers that a given DATA should no longer be expected. + + - 1: Enable extension + - 0: Disable + + Default: 1 + +max_burst - INTEGER + The limit of the number of new packets that can be initially sent. It + controls how bursty the generated traffic can be. + + Default: 4 + +association_max_retrans - INTEGER + Set the maximum number for retransmissions that an association can + attempt deciding that the remote end is unreachable. If this value + is exceeded, the association is terminated. + + Default: 10 + +max_init_retransmits - INTEGER + The maximum number of retransmissions of INIT and COOKIE-ECHO chunks + that an association will attempt before declaring the destination + unreachable and terminating. + + Default: 8 + +path_max_retrans - INTEGER + The maximum number of retransmissions that will be attempted on a given + path. Once this threshold is exceeded, the path is considered + unreachable, and new traffic will use a different path when the + association is multihomed. + + Default: 5 + +pf_retrans - INTEGER + The number of retransmissions that will be attempted on a given path + before traffic is redirected to an alternate transport (should one + exist). Note this is distinct from path_max_retrans, as a path that + passes the pf_retrans threshold can still be used. Its only + deprioritized when a transmission path is selected by the stack. This + setting is primarily used to enable fast failover mechanisms without + having to reduce path_max_retrans to a very low value. See: + http://www.ietf.org/id/draft-nishida-tsvwg-sctp-failover-05.txt + for details. Note also that a value of pf_retrans > path_max_retrans + disables this feature. Since both pf_retrans and path_max_retrans can + be changed by userspace application, a variable pf_enable is used to + disable pf state. + + Default: 0 + +ps_retrans - INTEGER + Primary.Switchover.Max.Retrans (PSMR), it's a tunable parameter coming + from section-5 "Primary Path Switchover" in rfc7829. The primary path + will be changed to another active path when the path error counter on + the old primary path exceeds PSMR, so that "the SCTP sender is allowed + to continue data transmission on a new working path even when the old + primary destination address becomes active again". Note this feature + is disabled by initializing 'ps_retrans' per netns as 0xffff by default, + and its value can't be less than 'pf_retrans' when changing by sysctl. + + Default: 0xffff + +rto_initial - INTEGER + The initial round trip timeout value in milliseconds that will be used + in calculating round trip times. This is the initial time interval + for retransmissions. + + Default: 3000 + +rto_max - INTEGER + The maximum value (in milliseconds) of the round trip timeout. This + is the largest time interval that can elapse between retransmissions. + + Default: 60000 + +rto_min - INTEGER + The minimum value (in milliseconds) of the round trip timeout. This + is the smallest time interval the can elapse between retransmissions. + + Default: 1000 + +hb_interval - INTEGER + The interval (in milliseconds) between HEARTBEAT chunks. These chunks + are sent at the specified interval on idle paths to probe the state of + a given path between 2 associations. + + Default: 30000 + +sack_timeout - INTEGER + The amount of time (in milliseconds) that the implementation will wait + to send a SACK. + + Default: 200 + +valid_cookie_life - INTEGER + The default lifetime of the SCTP cookie (in milliseconds). The cookie + is used during association establishment. + + Default: 60000 + +cookie_preserve_enable - BOOLEAN + Enable or disable the ability to extend the lifetime of the SCTP cookie + that is used during the establishment phase of SCTP association + + - 1: Enable cookie lifetime extension. + - 0: Disable + + Default: 1 + +cookie_hmac_alg - STRING + Select the hmac algorithm used when generating the cookie value sent by + a listening sctp socket to a connecting client in the INIT-ACK chunk. + Valid values are: + + * md5 + * sha1 + * none + + Ability to assign md5 or sha1 as the selected alg is predicated on the + configuration of those algorithms at build time (CONFIG_CRYPTO_MD5 and + CONFIG_CRYPTO_SHA1). + + Default: Dependent on configuration. MD5 if available, else SHA1 if + available, else none. + +rcvbuf_policy - INTEGER + Determines if the receive buffer is attributed to the socket or to + association. SCTP supports the capability to create multiple + associations on a single socket. When using this capability, it is + possible that a single stalled association that's buffering a lot + of data may block other associations from delivering their data by + consuming all of the receive buffer space. To work around this, + the rcvbuf_policy could be set to attribute the receiver buffer space + to each association instead of the socket. This prevents the described + blocking. + + - 1: rcvbuf space is per association + - 0: rcvbuf space is per socket + + Default: 0 + +sndbuf_policy - INTEGER + Similar to rcvbuf_policy above, this applies to send buffer space. + + - 1: Send buffer is tracked per association + - 0: Send buffer is tracked per socket. + + Default: 0 + +sctp_mem - vector of 3 INTEGERs: min, pressure, max + Number of pages allowed for queueing by all SCTP sockets. + + min: Below this number of pages SCTP is not bothered about its + memory appetite. When amount of memory allocated by SCTP exceeds + this number, SCTP starts to moderate memory usage. + + pressure: This value was introduced to follow format of tcp_mem. + + max: Number of pages allowed for queueing by all SCTP sockets. + + Default is calculated at boot time from amount of available memory. + +sctp_rmem - vector of 3 INTEGERs: min, default, max + Only the first value ("min") is used, "default" and "max" are + ignored. + + min: Minimal size of receive buffer used by SCTP socket. + It is guaranteed to each SCTP socket (but not association) even + under moderate memory pressure. + + Default: 4K + +sctp_wmem - vector of 3 INTEGERs: min, default, max + Only the first value ("min") is used, "default" and "max" are + ignored. + + min: Minimum size of send buffer that can be used by SCTP sockets. + It is guaranteed to each SCTP socket (but not association) even + under moderate memory pressure. + + Default: 4K + +addr_scope_policy - INTEGER + Control IPv4 address scoping - draft-stewart-tsvwg-sctp-ipv4-00 + + - 0 - Disable IPv4 address scoping + - 1 - Enable IPv4 address scoping + - 2 - Follow draft but allow IPv4 private addresses + - 3 - Follow draft but allow IPv4 link local addresses + + Default: 1 + +udp_port - INTEGER + The listening port for the local UDP tunneling sock. Normally it's + using the IANA-assigned UDP port number 9899 (sctp-tunneling). + + This UDP sock is used for processing the incoming UDP-encapsulated + SCTP packets (from RFC6951), and shared by all applications in the + same net namespace. This UDP sock will be closed when the value is + set to 0. + + The value will also be used to set the src port of the UDP header + for the outgoing UDP-encapsulated SCTP packets. For the dest port, + please refer to 'encap_port' below. + + Default: 0 + +encap_port - INTEGER + The default remote UDP encapsulation port. + + This value is used to set the dest port of the UDP header for the + outgoing UDP-encapsulated SCTP packets by default. Users can also + change the value for each sock/asoc/transport by using setsockopt. + For further information, please refer to RFC6951. + + Note that when connecting to a remote server, the client should set + this to the port that the UDP tunneling sock on the peer server is + listening to and the local UDP tunneling sock on the client also + must be started. On the server, it would get the encap_port from + the incoming packet's source port. + + Default: 0 + +plpmtud_probe_interval - INTEGER + The time interval (in milliseconds) for the PLPMTUD probe timer, + which is configured to expire after this period to receive an + acknowledgment to a probe packet. This is also the time interval + between the probes for the current pmtu when the probe search + is done. + + PLPMTUD will be disabled when 0 is set, and other values for it + must be >= 5000. + + Default: 0 + +reconf_enable - BOOLEAN + Enable or disable extension of Stream Reconfiguration functionality + specified in RFC6525. This extension provides the ability to "reset" + a stream, and it includes the Parameters of "Outgoing/Incoming SSN + Reset", "SSN/TSN Reset" and "Add Outgoing/Incoming Streams". + + - 1: Enable extension. + - 0: Disable extension. + + Default: 0 + +intl_enable - BOOLEAN + Enable or disable extension of User Message Interleaving functionality + specified in RFC8260. This extension allows the interleaving of user + messages sent on different streams. With this feature enabled, I-DATA + chunk will replace DATA chunk to carry user messages if also supported + by the peer. Note that to use this feature, one needs to set this option + to 1 and also needs to set socket options SCTP_FRAGMENT_INTERLEAVE to 2 + and SCTP_INTERLEAVING_SUPPORTED to 1. + + - 1: Enable extension. + - 0: Disable extension. + + Default: 0 + +ecn_enable - BOOLEAN + Control use of Explicit Congestion Notification (ECN) by SCTP. + Like in TCP, ECN is used only when both ends of the SCTP connection + indicate support for it. This feature is useful in avoiding losses + due to congestion by allowing supporting routers to signal congestion + before having to drop packets. + + 1: Enable ecn. + 0: Disable ecn. + + Default: 1 + +l3mdev_accept - BOOLEAN + Enabling this option allows a "global" bound socket to work + across L3 master domains (e.g., VRFs) with packets capable of + being received regardless of the L3 domain in which they + originated. Only valid when the kernel was compiled with + CONFIG_NET_L3_MASTER_DEV. + + Default: 1 (enabled) + + +``/proc/sys/net/core/*`` +======================== + + Please see: Documentation/admin-guide/sysctl/net.rst for descriptions of these entries. + + +``/proc/sys/net/unix/*`` +======================== + +max_dgram_qlen - INTEGER + The maximum length of dgram socket receive queue + + Default: 10 + diff --git a/Documentation/networking/ip_dynaddr.rst b/Documentation/networking/ip_dynaddr.rst new file mode 100644 index 0000000000..eacc0c780c --- /dev/null +++ b/Documentation/networking/ip_dynaddr.rst @@ -0,0 +1,40 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================================== +IP dynamic address hack-port v0.03 +================================== + +This stuff allows diald ONESHOT connections to get established by +dynamically changing packet source address (and socket's if local procs). +It is implemented for TCP diald-box connections(1) and IP_MASQuerading(2). + +If enabled\ [#]_ and forwarding interface has changed: + + 1) Socket (and packet) source address is rewritten ON RETRANSMISSIONS + while in SYN_SENT state (diald-box processes). + 2) Out-bounded MASQueraded source address changes ON OUTPUT (when + internal host does retransmission) until a packet from outside is + received by the tunnel. + +This is specially helpful for auto dialup links (diald), where the +``actual`` outgoing address is unknown at the moment the link is +going up. So, the *same* (local AND masqueraded) connections requests that +bring the link up will be able to get established. + +.. [#] At boot, by default no address rewriting is attempted. + + To enable:: + + # echo 1 > /proc/sys/net/ipv4/ip_dynaddr + + To enable verbose mode:: + + # echo 2 > /proc/sys/net/ipv4/ip_dynaddr + + To disable (default):: + + # echo 0 > /proc/sys/net/ipv4/ip_dynaddr + +Enjoy! + +Juanjo <jjciarla@raiz.uncu.edu.ar> diff --git a/Documentation/networking/ipddp.rst b/Documentation/networking/ipddp.rst new file mode 100644 index 0000000000..be7091b779 --- /dev/null +++ b/Documentation/networking/ipddp.rst @@ -0,0 +1,78 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================================================= +AppleTalk-IP Decapsulation and AppleTalk-IP Encapsulation +========================================================= + +Documentation ipddp.c + +This file is written by Jay Schulist <jschlst@samba.org> + +Introduction +------------ + +AppleTalk-IP (IPDDP) is the method computers connected to AppleTalk +networks can use to communicate via IP. AppleTalk-IP is simply IP datagrams +inside AppleTalk packets. + +Through this driver you can either allow your Linux box to communicate +IP over an AppleTalk network or you can provide IP gatewaying functions +for your AppleTalk users. + +You can currently encapsulate or decapsulate AppleTalk-IP on LocalTalk, +EtherTalk and PPPTalk. The only limit on the protocol is that of what +kernel AppleTalk layer and drivers are available. + +Each mode requires its own user space software. + +Compiling AppleTalk-IP Decapsulation/Encapsulation +================================================== + +AppleTalk-IP decapsulation needs to be compiled into your kernel. You +will need to turn on AppleTalk-IP driver support. Then you will need to +select ONE of the two options; IP to AppleTalk-IP encapsulation support or +AppleTalk-IP to IP decapsulation support. If you compile the driver +statically you will only be able to use the driver for the function you have +enabled in the kernel. If you compile the driver as a module you can +select what mode you want it to run in via a module loading param. +ipddp_mode=1 for AppleTalk-IP encapsulation and ipddp_mode=2 for +AppleTalk-IP to IP decapsulation. + +Basic instructions for user space tools +======================================= + +I will briefly describe the operation of the tools, but you will +need to consult the supporting documentation for each set of tools. + +Decapsulation - You will need to download a software package called +MacGate. In this distribution there will be a tool called MacRoute +which enables you to add routes to the kernel for your Macs by hand. +Also the tool MacRegGateWay is included to register the +proper IP Gateway and IP addresses for your machine. Included in this +distribution is a patch to netatalk-1.4b2+asun2.0a17.2 (available from +ftp.u.washington.edu/pub/user-supported/asun/) this patch is optional +but it allows automatic adding and deleting of routes for Macs. (Handy +for locations with large Mac installations) + +Encapsulation - You will need to download a software daemon called ipddpd. +This software expects there to be an AppleTalk-IP gateway on the network. +You will also need to add the proper routes to route your Linux box's IP +traffic out the ipddp interface. + +Common Uses of ipddp.c +---------------------- +Of course AppleTalk-IP decapsulation and encapsulation, but specifically +decapsulation is being used most for connecting LocalTalk networks to +IP networks. Although it has been used on EtherTalk networks to allow +Macs that are only able to tunnel IP over EtherTalk. + +Encapsulation has been used to allow a Linux box stuck on a LocalTalk +network to use IP. It should work equally well if you are stuck on an +EtherTalk only network. + +Further Assistance +------------------- +You can contact me (Jay Schulist <jschlst@samba.org>) with any +questions regarding decapsulation or encapsulation. Bradford W. Johnson +<johns393@maroon.tc.umn.edu> originally wrote the ipddp.c driver for IP +encapsulation in AppleTalk. diff --git a/Documentation/networking/ipsec.rst b/Documentation/networking/ipsec.rst new file mode 100644 index 0000000000..afe9d7b48b --- /dev/null +++ b/Documentation/networking/ipsec.rst @@ -0,0 +1,46 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===== +IPsec +===== + + +Here documents known IPsec corner cases which need to be keep in mind when +deploy various IPsec configuration in real world production environment. + +1. IPcomp: + Small IP packet won't get compressed at sender, and failed on + policy check on receiver. + +Quote from RFC3173:: + + 2.2. Non-Expansion Policy + + If the total size of a compressed payload and the IPComp header, as + defined in section 3, is not smaller than the size of the original + payload, the IP datagram MUST be sent in the original non-compressed + form. To clarify: If an IP datagram is sent non-compressed, no + + IPComp header is added to the datagram. This policy ensures saving + the decompression processing cycles and avoiding incurring IP + datagram fragmentation when the expanded datagram is larger than the + MTU. + + Small IP datagrams are likely to expand as a result of compression. + Therefore, a numeric threshold should be applied before compression, + where IP datagrams of size smaller than the threshold are sent in the + original form without attempting compression. The numeric threshold + is implementation dependent. + +Current IPComp implementation is indeed by the book, while as in practice +when sending non-compressed packet to the peer (whether or not packet len +is smaller than the threshold or the compressed len is larger than original +packet len), the packet is dropped when checking the policy as this packet +matches the selector but not coming from any XFRM layer, i.e., with no +security path. Such naked packet will not eventually make it to upper layer. +The result is much more wired to the user when ping peer with different +payload length. + +One workaround is try to set "level use" for each policy if user observed +above scenario. The consequence of doing so is small packet(uncompressed) +will skip policy checking on receiver side. diff --git a/Documentation/networking/ipv6.rst b/Documentation/networking/ipv6.rst new file mode 100644 index 0000000000..ba09c2f2dc --- /dev/null +++ b/Documentation/networking/ipv6.rst @@ -0,0 +1,78 @@ +.. SPDX-License-Identifier: GPL-2.0 + +==== +IPv6 +==== + + +Options for the ipv6 module are supplied as parameters at load time. + +Module options may be given as command line arguments to the insmod +or modprobe command, but are usually specified in either +``/etc/modules.d/*.conf`` configuration files, or in a distro-specific +configuration file. + +The available ipv6 module parameters are listed below. If a parameter +is not specified the default value is used. + +The parameters are as follows: + +disable + + Specifies whether to load the IPv6 module, but disable all + its functionality. This might be used when another module + has a dependency on the IPv6 module being loaded, but no + IPv6 addresses or operations are desired. + + The possible values and their effects are: + + 0 + IPv6 is enabled. + + This is the default value. + + 1 + IPv6 is disabled. + + No IPv6 addresses will be added to interfaces, and + it will not be possible to open an IPv6 socket. + + A reboot is required to enable IPv6. + +autoconf + + Specifies whether to enable IPv6 address autoconfiguration + on all interfaces. This might be used when one does not wish + for addresses to be automatically generated from prefixes + received in Router Advertisements. + + The possible values and their effects are: + + 0 + IPv6 address autoconfiguration is disabled on all interfaces. + + Only the IPv6 loopback address (::1) and link-local addresses + will be added to interfaces. + + 1 + IPv6 address autoconfiguration is enabled on all interfaces. + + This is the default value. + +disable_ipv6 + + Specifies whether to disable IPv6 on all interfaces. + This might be used when no IPv6 addresses are desired. + + The possible values and their effects are: + + 0 + IPv6 is enabled on all interfaces. + + This is the default value. + + 1 + IPv6 is disabled on all interfaces. + + No IPv6 addresses will be added to interfaces. + diff --git a/Documentation/networking/ipvlan.rst b/Documentation/networking/ipvlan.rst new file mode 100644 index 0000000000..895d0ccfd5 --- /dev/null +++ b/Documentation/networking/ipvlan.rst @@ -0,0 +1,189 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=================== +IPVLAN Driver HOWTO +=================== + +Initial Release: + Mahesh Bandewar <maheshb AT google.com> + +1. Introduction: +================ +This is conceptually very similar to the macvlan driver with one major +exception of using L3 for mux-ing /demux-ing among slaves. This property makes +the master device share the L2 with its slave devices. I have developed this +driver in conjunction with network namespaces and not sure if there is use case +outside of it. + + +2. Building and Installation: +============================= + +In order to build the driver, please select the config item CONFIG_IPVLAN. +The driver can be built into the kernel (CONFIG_IPVLAN=y) or as a module +(CONFIG_IPVLAN=m). + + +3. Configuration: +================= + +There are no module parameters for this driver and it can be configured +using IProute2/ip utility. +:: + + ip link add link <master> name <slave> type ipvlan [ mode MODE ] [ FLAGS ] + where + MODE: l3 (default) | l3s | l2 + FLAGS: bridge (default) | private | vepa + +e.g. + + (a) Following will create IPvlan link with eth0 as master in + L3 bridge mode:: + + bash# ip link add link eth0 name ipvl0 type ipvlan + (b) This command will create IPvlan link in L2 bridge mode:: + + bash# ip link add link eth0 name ipvl0 type ipvlan mode l2 bridge + + (c) This command will create an IPvlan device in L2 private mode:: + + bash# ip link add link eth0 name ipvlan type ipvlan mode l2 private + + (d) This command will create an IPvlan device in L2 vepa mode:: + + bash# ip link add link eth0 name ipvlan type ipvlan mode l2 vepa + + +4. Operating modes: +=================== + +IPvlan has two modes of operation - L2 and L3. For a given master device, +you can select one of these two modes and all slaves on that master will +operate in the same (selected) mode. The RX mode is almost identical except +that in L3 mode the slaves won't receive any multicast / broadcast traffic. +L3 mode is more restrictive since routing is controlled from the other (mostly) +default namespace. + +4.1 L2 mode: +------------ + +In this mode TX processing happens on the stack instance attached to the +slave device and packets are switched and queued to the master device to send +out. In this mode the slaves will RX/TX multicast and broadcast (if applicable) +as well. + +4.2 L3 mode: +------------ + +In this mode TX processing up to L3 happens on the stack instance attached +to the slave device and packets are switched to the stack instance of the +master device for the L2 processing and routing from that instance will be +used before packets are queued on the outbound device. In this mode the slaves +will not receive nor can send multicast / broadcast traffic. + +4.3 L3S mode: +------------- + +This is very similar to the L3 mode except that iptables (conn-tracking) +works in this mode and hence it is L3-symmetric (L3s). This will have slightly less +performance but that shouldn't matter since you are choosing this mode over plain-L3 +mode to make conn-tracking work. + +5. Mode flags: +============== + +At this time following mode flags are available + +5.1 bridge: +----------- +This is the default option. To configure the IPvlan port in this mode, +user can choose to either add this option on the command-line or don't specify +anything. This is the traditional mode where slaves can cross-talk among +themselves apart from talking through the master device. + +5.2 private: +------------ +If this option is added to the command-line, the port is set in private +mode. i.e. port won't allow cross communication between slaves. + +5.3 vepa: +--------- +If this is added to the command-line, the port is set in VEPA mode. +i.e. port will offload switching functionality to the external entity as +described in 802.1Qbg +Note: VEPA mode in IPvlan has limitations. IPvlan uses the mac-address of the +master-device, so the packets which are emitted in this mode for the adjacent +neighbor will have source and destination mac same. This will make the switch / +router send the redirect message. + +6. What to choose (macvlan vs. ipvlan)? +======================================= + +These two devices are very similar in many regards and the specific use +case could very well define which device to choose. if one of the following +situations defines your use case then you can choose to use ipvlan: + + +(a) The Linux host that is connected to the external switch / router has + policy configured that allows only one mac per port. +(b) No of virtual devices created on a master exceed the mac capacity and + puts the NIC in promiscuous mode and degraded performance is a concern. +(c) If the slave device is to be put into the hostile / untrusted network + namespace where L2 on the slave could be changed / misused. + + +6. Example configuration: +========================= + +:: + + +=============================================================+ + | Host: host1 | + | | + | +----------------------+ +----------------------+ | + | | NS:ns0 | | NS:ns1 | | + | | | | | | + | | | | | | + | | ipvl0 | | ipvl1 | | + | +----------#-----------+ +-----------#----------+ | + | # # | + | ################################ | + | # eth0 | + +==============================#==============================+ + + +(a) Create two network namespaces - ns0, ns1:: + + ip netns add ns0 + ip netns add ns1 + +(b) Create two ipvlan slaves on eth0 (master device):: + + ip link add link eth0 ipvl0 type ipvlan mode l2 + ip link add link eth0 ipvl1 type ipvlan mode l2 + +(c) Assign slaves to the respective network namespaces:: + + ip link set dev ipvl0 netns ns0 + ip link set dev ipvl1 netns ns1 + +(d) Now switch to the namespace (ns0 or ns1) to configure the slave devices + + - For ns0:: + + (1) ip netns exec ns0 bash + (2) ip link set dev ipvl0 up + (3) ip link set dev lo up + (4) ip -4 addr add 127.0.0.1 dev lo + (5) ip -4 addr add $IPADDR dev ipvl0 + (6) ip -4 route add default via $ROUTER dev ipvl0 + + - For ns1:: + + (1) ip netns exec ns1 bash + (2) ip link set dev ipvl1 up + (3) ip link set dev lo up + (4) ip -4 addr add 127.0.0.1 dev lo + (5) ip -4 addr add $IPADDR dev ipvl1 + (6) ip -4 route add default via $ROUTER dev ipvl1 diff --git a/Documentation/networking/ipvs-sysctl.rst b/Documentation/networking/ipvs-sysctl.rst new file mode 100644 index 0000000000..3fb5fa142e --- /dev/null +++ b/Documentation/networking/ipvs-sysctl.rst @@ -0,0 +1,332 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=========== +IPvs-sysctl +=========== + +/proc/sys/net/ipv4/vs/* Variables: +================================== + +am_droprate - INTEGER + default 10 + + It sets the always mode drop rate, which is used in the mode 3 + of the drop_rate defense. + +amemthresh - INTEGER + default 1024 + + It sets the available memory threshold (in pages), which is + used in the automatic modes of defense. When there is no + enough available memory, the respective strategy will be + enabled and the variable is automatically set to 2, otherwise + the strategy is disabled and the variable is set to 1. + +backup_only - BOOLEAN + - 0 - disabled (default) + - not 0 - enabled + + If set, disable the director function while the server is + in backup mode to avoid packet loops for DR/TUN methods. + +conn_reuse_mode - INTEGER + 1 - default + + Controls how ipvs will deal with connections that are detected + port reuse. It is a bitmap, with the values being: + + 0: disable any special handling on port reuse. The new + connection will be delivered to the same real server that was + servicing the previous connection. + + bit 1: enable rescheduling of new connections when it is safe. + That is, whenever expire_nodest_conn and for TCP sockets, when + the connection is in TIME_WAIT state (which is only possible if + you use NAT mode). + + bit 2: it is bit 1 plus, for TCP connections, when connections + are in FIN_WAIT state, as this is the last state seen by load + balancer in Direct Routing mode. This bit helps on adding new + real servers to a very busy cluster. + +conntrack - BOOLEAN + - 0 - disabled (default) + - not 0 - enabled + + If set, maintain connection tracking entries for + connections handled by IPVS. + + This should be enabled if connections handled by IPVS are to be + also handled by stateful firewall rules. That is, iptables rules + that make use of connection tracking. It is a performance + optimisation to disable this setting otherwise. + + Connections handled by the IPVS FTP application module + will have connection tracking entries regardless of this setting. + + Only available when IPVS is compiled with CONFIG_IP_VS_NFCT enabled. + +cache_bypass - BOOLEAN + - 0 - disabled (default) + - not 0 - enabled + + If it is enabled, forward packets to the original destination + directly when no cache server is available and destination + address is not local (iph->daddr is RTN_UNICAST). It is mostly + used in transparent web cache cluster. + +debug_level - INTEGER + - 0 - transmission error messages (default) + - 1 - non-fatal error messages + - 2 - configuration + - 3 - destination trash + - 4 - drop entry + - 5 - service lookup + - 6 - scheduling + - 7 - connection new/expire, lookup and synchronization + - 8 - state transition + - 9 - binding destination, template checks and applications + - 10 - IPVS packet transmission + - 11 - IPVS packet handling (ip_vs_in/ip_vs_out) + - 12 or more - packet traversal + + Only available when IPVS is compiled with CONFIG_IP_VS_DEBUG enabled. + + Higher debugging levels include the messages for lower debugging + levels, so setting debug level 2, includes level 0, 1 and 2 + messages. Thus, logging becomes more and more verbose the higher + the level. + +drop_entry - INTEGER + - 0 - disabled (default) + + The drop_entry defense is to randomly drop entries in the + connection hash table, just in order to collect back some + memory for new connections. In the current code, the + drop_entry procedure can be activated every second, then it + randomly scans 1/32 of the whole and drops entries that are in + the SYN-RECV/SYNACK state, which should be effective against + syn-flooding attack. + + The valid values of drop_entry are from 0 to 3, where 0 means + that this strategy is always disabled, 1 and 2 mean automatic + modes (when there is no enough available memory, the strategy + is enabled and the variable is automatically set to 2, + otherwise the strategy is disabled and the variable is set to + 1), and 3 means that the strategy is always enabled. + +drop_packet - INTEGER + - 0 - disabled (default) + + The drop_packet defense is designed to drop 1/rate packets + before forwarding them to real servers. If the rate is 1, then + drop all the incoming packets. + + The value definition is the same as that of the drop_entry. In + the automatic mode, the rate is determined by the follow + formula: rate = amemthresh / (amemthresh - available_memory) + when available memory is less than the available memory + threshold. When the mode 3 is set, the always mode drop rate + is controlled by the /proc/sys/net/ipv4/vs/am_droprate. + +est_cpulist - CPULIST + Allowed CPUs for estimation kthreads + + Syntax: standard cpulist format + empty list - stop kthread tasks and estimation + default - the system's housekeeping CPUs for kthreads + + Example: + "all": all possible CPUs + "0-N": all possible CPUs, N denotes last CPU number + "0,1-N:1/2": first and all CPUs with odd number + "": empty list + +est_nice - INTEGER + default 0 + Valid range: -20 (more favorable) .. 19 (less favorable) + + Niceness value to use for the estimation kthreads (scheduling + priority) + +expire_nodest_conn - BOOLEAN + - 0 - disabled (default) + - not 0 - enabled + + The default value is 0, the load balancer will silently drop + packets when its destination server is not available. It may + be useful, when user-space monitoring program deletes the + destination server (because of server overload or wrong + detection) and add back the server later, and the connections + to the server can continue. + + If this feature is enabled, the load balancer will expire the + connection immediately when a packet arrives and its + destination server is not available, then the client program + will be notified that the connection is closed. This is + equivalent to the feature some people requires to flush + connections when its destination is not available. + +expire_quiescent_template - BOOLEAN + - 0 - disabled (default) + - not 0 - enabled + + When set to a non-zero value, the load balancer will expire + persistent templates when the destination server is quiescent. + This may be useful, when a user makes a destination server + quiescent by setting its weight to 0 and it is desired that + subsequent otherwise persistent connections are sent to a + different destination server. By default new persistent + connections are allowed to quiescent destination servers. + + If this feature is enabled, the load balancer will expire the + persistence template if it is to be used to schedule a new + connection and the destination server is quiescent. + +ignore_tunneled - BOOLEAN + - 0 - disabled (default) + - not 0 - enabled + + If set, ipvs will set the ipvs_property on all packets which are of + unrecognized protocols. This prevents us from routing tunneled + protocols like ipip, which is useful to prevent rescheduling + packets that have been tunneled to the ipvs host (i.e. to prevent + ipvs routing loops when ipvs is also acting as a real server). + +nat_icmp_send - BOOLEAN + - 0 - disabled (default) + - not 0 - enabled + + It controls sending icmp error messages (ICMP_DEST_UNREACH) + for VS/NAT when the load balancer receives packets from real + servers but the connection entries don't exist. + +pmtu_disc - BOOLEAN + - 0 - disabled + - not 0 - enabled (default) + + By default, reject with FRAG_NEEDED all DF packets that exceed + the PMTU, irrespective of the forwarding method. For TUN method + the flag can be disabled to fragment such packets. + +secure_tcp - INTEGER + - 0 - disabled (default) + + The secure_tcp defense is to use a more complicated TCP state + transition table. For VS/NAT, it also delays entering the + TCP ESTABLISHED state until the three way handshake is completed. + + The value definition is the same as that of drop_entry and + drop_packet. + +sync_threshold - vector of 2 INTEGERs: sync_threshold, sync_period + default 3 50 + + It sets synchronization threshold, which is the minimum number + of incoming packets that a connection needs to receive before + the connection will be synchronized. A connection will be + synchronized, every time the number of its incoming packets + modulus sync_period equals the threshold. The range of the + threshold is from 0 to sync_period. + + When sync_period and sync_refresh_period are 0, send sync only + for state changes or only once when pkts matches sync_threshold + +sync_refresh_period - UNSIGNED INTEGER + default 0 + + In seconds, difference in reported connection timer that triggers + new sync message. It can be used to avoid sync messages for the + specified period (or half of the connection timeout if it is lower) + if connection state is not changed since last sync. + + This is useful for normal connections with high traffic to reduce + sync rate. Additionally, retry sync_retries times with period of + sync_refresh_period/8. + +sync_retries - INTEGER + default 0 + + Defines sync retries with period of sync_refresh_period/8. Useful + to protect against loss of sync messages. The range of the + sync_retries is from 0 to 3. + +sync_qlen_max - UNSIGNED LONG + + Hard limit for queued sync messages that are not sent yet. It + defaults to 1/32 of the memory pages but actually represents + number of messages. It will protect us from allocating large + parts of memory when the sending rate is lower than the queuing + rate. + +sync_sock_size - INTEGER + default 0 + + Configuration of SNDBUF (master) or RCVBUF (slave) socket limit. + Default value is 0 (preserve system defaults). + +sync_ports - INTEGER + default 1 + + The number of threads that master and backup servers can use for + sync traffic. Every thread will use single UDP port, thread 0 will + use the default port 8848 while last thread will use port + 8848+sync_ports-1. + +snat_reroute - BOOLEAN + - 0 - disabled + - not 0 - enabled (default) + + If enabled, recalculate the route of SNATed packets from + realservers so that they are routed as if they originate from the + director. Otherwise they are routed as if they are forwarded by the + director. + + If policy routing is in effect then it is possible that the route + of a packet originating from a director is routed differently to a + packet being forwarded by the director. + + If policy routing is not in effect then the recalculated route will + always be the same as the original route so it is an optimisation + to disable snat_reroute and avoid the recalculation. + +sync_persist_mode - INTEGER + default 0 + + Controls the synchronisation of connections when using persistence + + 0: All types of connections are synchronised + + 1: Attempt to reduce the synchronisation traffic depending on + the connection type. For persistent services avoid synchronisation + for normal connections, do it only for persistence templates. + In such case, for TCP and SCTP it may need enabling sloppy_tcp and + sloppy_sctp flags on backup servers. For non-persistent services + such optimization is not applied, mode 0 is assumed. + +sync_version - INTEGER + default 1 + + The version of the synchronisation protocol used when sending + synchronisation messages. + + 0 selects the original synchronisation protocol (version 0). This + should be used when sending synchronisation messages to a legacy + system that only understands the original synchronisation protocol. + + 1 selects the current synchronisation protocol (version 1). This + should be used where possible. + + Kernels with this sync_version entry are able to receive messages + of both version 1 and version 2 of the synchronisation protocol. + +run_estimation - BOOLEAN + 0 - disabled + not 0 - enabled (default) + + If disabled, the estimation will be suspended and kthread tasks + stopped. + + You can always re-enable estimation by setting this value to 1. + But be careful, the first estimation after re-enable is not + accurate. diff --git a/Documentation/networking/j1939.rst b/Documentation/networking/j1939.rst new file mode 100644 index 0000000000..e4bd7aa1f5 --- /dev/null +++ b/Documentation/networking/j1939.rst @@ -0,0 +1,460 @@ +.. SPDX-License-Identifier: (GPL-2.0 OR MIT) + +=================== +J1939 Documentation +=================== + +Overview / What Is J1939 +======================== + +SAE J1939 defines a higher layer protocol on CAN. It implements a more +sophisticated addressing scheme and extends the maximum packet size above 8 +bytes. Several derived specifications exist, which differ from the original +J1939 on the application level, like MilCAN A, NMEA2000, and especially +ISO-11783 (ISOBUS). This last one specifies the so-called ETP (Extended +Transport Protocol), which has been included in this implementation. This +results in a maximum packet size of ((2 ^ 24) - 1) * 7 bytes == 111 MiB. + +Specifications used +------------------- + +* SAE J1939-21 : data link layer +* SAE J1939-81 : network management +* ISO 11783-6 : Virtual Terminal (Extended Transport Protocol) + +.. _j1939-motivation: + +Motivation +========== + +Given the fact there's something like SocketCAN with an API similar to BSD +sockets, we found some reasons to justify a kernel implementation for the +addressing and transport methods used by J1939. + +* **Addressing:** when a process on an ECU communicates via J1939, it should + not necessarily know its source address. Although, at least one process per + ECU should know the source address. Other processes should be able to reuse + that address. This way, address parameters for different processes + cooperating for the same ECU, are not duplicated. This way of working is + closely related to the UNIX concept, where programs do just one thing and do + it well. + +* **Dynamic addressing:** Address Claiming in J1939 is time critical. + Furthermore, data transport should be handled properly during the address + negotiation. Putting this functionality in the kernel eliminates it as a + requirement for _every_ user space process that communicates via J1939. This + results in a consistent J1939 bus with proper addressing. + +* **Transport:** both TP & ETP reuse some PGNs to relay big packets over them. + Different processes may thus use the same TP & ETP PGNs without actually + knowing it. The individual TP & ETP sessions _must_ be serialized + (synchronized) between different processes. The kernel solves this problem + properly and eliminates the serialization (synchronization) as a requirement + for _every_ user space process that communicates via J1939. + +J1939 defines some other features (relaying, gateway, fast packet transport, +...). In-kernel code for these would not contribute to protocol stability. +Therefore, these parts are left to user space. + +The J1939 sockets operate on CAN network devices (see SocketCAN). Any J1939 +user space library operating on CAN raw sockets will still operate properly. +Since such a library does not communicate with the in-kernel implementation, care +must be taken that these two do not interfere. In practice, this means they +cannot share ECU addresses. A single ECU (or virtual ECU) address is used by +the library exclusively, or by the in-kernel system exclusively. + +J1939 concepts +============== + +PGN +--- + +The J1939 protocol uses the 29-bit CAN identifier with the following structure: + + ============ ============== ==================== + 29 bit CAN-ID + -------------------------------------------------- + Bit positions within the CAN-ID + -------------------------------------------------- + 28 ... 26 25 ... 8 7 ... 0 + ============ ============== ==================== + Priority PGN SA (Source Address) + ============ ============== ==================== + +The PGN (Parameter Group Number) is a number to identify a packet. The PGN +is composed as follows: + + ============ ============== ================= ================= + PGN + ------------------------------------------------------------------ + Bit positions within the CAN-ID + ------------------------------------------------------------------ + 25 24 23 ... 16 15 ... 8 + ============ ============== ================= ================= + R (Reserved) DP (Data Page) PF (PDU Format) PS (PDU Specific) + ============ ============== ================= ================= + +In J1939-21 distinction is made between PDU1 format (where PF < 240) and PDU2 +format (where PF >= 240). Furthermore, when using the PDU2 format, the PS-field +contains a so-called Group Extension, which is part of the PGN. When using PDU2 +format, the Group Extension is set in the PS-field. + + ============== ======================== + PDU1 Format (specific) (peer to peer) + ---------------------------------------- + Bit positions within the CAN-ID + ---------------------------------------- + 23 ... 16 15 ... 8 + ============== ======================== + 00h ... EFh DA (Destination address) + ============== ======================== + + ============== ======================== + PDU2 Format (global) (broadcast) + ---------------------------------------- + Bit positions within the CAN-ID + ---------------------------------------- + 23 ... 16 15 ... 8 + ============== ======================== + F0h ... FFh GE (Group Extension) + ============== ======================== + +On the other hand, when using PDU1 format, the PS-field contains a so-called +Destination Address, which is _not_ part of the PGN. When communicating a PGN +from user space to kernel (or vice versa) and PDU2 format is used, the PS-field +of the PGN shall be set to zero. The Destination Address shall be set +elsewhere. + +Regarding PGN mapping to 29-bit CAN identifier, the Destination Address shall +be get/set from/to the appropriate bits of the identifier by the kernel. + + +Addressing +---------- + +Both static and dynamic addressing methods can be used. + +For static addresses, no extra checks are made by the kernel and provided +addresses are considered right. This responsibility is for the OEM or system +integrator. + +For dynamic addressing, so-called Address Claiming, extra support is foreseen +in the kernel. In J1939 any ECU is known by its 64-bit NAME. At the moment of +a successful address claim, the kernel keeps track of both NAME and source +address being claimed. This serves as a base for filter schemes. By default, +packets with a destination that is not locally will be rejected. + +Mixed mode packets (from a static to a dynamic address or vice versa) are +allowed. The BSD sockets define separate API calls for getting/setting the +local & remote address and are applicable for J1939 sockets. + +Filtering +--------- + +J1939 defines white list filters per socket that a user can set in order to +receive a subset of the J1939 traffic. Filtering can be based on: + +* SA +* SOURCE_NAME +* PGN + +When multiple filters are in place for a single socket, and a packet comes in +that matches several of those filters, the packet is only received once for +that socket. + +How to Use J1939 +================ + +API Calls +--------- + +On CAN, you first need to open a socket for communicating over a CAN network. +To use J1939, ``#include <linux/can/j1939.h>``. From there, ``<linux/can.h>`` will be +included too. To open a socket, use: + +.. code-block:: C + + s = socket(PF_CAN, SOCK_DGRAM, CAN_J1939); + +J1939 does use ``SOCK_DGRAM`` sockets. In the J1939 specification, connections are +mentioned in the context of transport protocol sessions. These still deliver +packets to the other end (using several CAN packets). ``SOCK_STREAM`` is not +supported. + +After the successful creation of the socket, you would normally use the ``bind(2)`` +and/or ``connect(2)`` system call to bind the socket to a CAN interface. After +binding and/or connecting the socket, you can ``read(2)`` and ``write(2)`` from/to the +socket or use ``send(2)``, ``sendto(2)``, ``sendmsg(2)`` and the ``recv*()`` counterpart +operations on the socket as usual. There are also J1939 specific socket options +described below. + +In order to send data, a ``bind(2)`` must have been successful. ``bind(2)`` assigns a +local address to a socket. + +Different from CAN is that the payload data is just the data that get sends, +without its header info. The header info is derived from the sockaddr supplied +to ``bind(2)``, ``connect(2)``, ``sendto(2)`` and ``recvfrom(2)``. A ``write(2)`` with size 4 will +result in a packet with 4 bytes. + +The sockaddr structure has extensions for use with J1939 as specified below: + +.. code-block:: C + + struct sockaddr_can { + sa_family_t can_family; + int can_ifindex; + union { + struct { + __u64 name; + /* pgn: + * 8 bit: PS in PDU2 case, else 0 + * 8 bit: PF + * 1 bit: DP + * 1 bit: reserved + */ + __u32 pgn; + __u8 addr; + } j1939; + } can_addr; + } + +``can_family`` & ``can_ifindex`` serve the same purpose as for other SocketCAN sockets. + +``can_addr.j1939.pgn`` specifies the PGN (max 0x3ffff). Individual bits are +specified above. + +``can_addr.j1939.name`` contains the 64-bit J1939 NAME. + +``can_addr.j1939.addr`` contains the address. + +The ``bind(2)`` system call assigns the local address, i.e. the source address when +sending packages. If a PGN during ``bind(2)`` is set, it's used as a RX filter. +I.e. only packets with a matching PGN are received. If an ADDR or NAME is set +it is used as a receive filter, too. It will match the destination NAME or ADDR +of the incoming packet. The NAME filter will work only if appropriate Address +Claiming for this name was done on the CAN bus and registered/cached by the +kernel. + +On the other hand ``connect(2)`` assigns the remote address, i.e. the destination +address. The PGN from ``connect(2)`` is used as the default PGN when sending +packets. If ADDR or NAME is set it will be used as the default destination ADDR +or NAME. Further a set ADDR or NAME during ``connect(2)`` is used as a receive +filter. It will match the source NAME or ADDR of the incoming packet. + +Both ``write(2)`` and ``send(2)`` will send a packet with local address from ``bind(2)`` and the +remote address from ``connect(2)``. Use ``sendto(2)`` to overwrite the destination +address. + +If ``can_addr.j1939.name`` is set (!= 0) the NAME is looked up by the kernel and +the corresponding ADDR is used. If ``can_addr.j1939.name`` is not set (== 0), +``can_addr.j1939.addr`` is used. + +When creating a socket, reasonable defaults are set. Some options can be +modified with ``setsockopt(2)`` & ``getsockopt(2)``. + +RX path related options: + +- ``SO_J1939_FILTER`` - configure array of filters +- ``SO_J1939_PROMISC`` - disable filters set by ``bind(2)`` and ``connect(2)`` + +By default no broadcast packets can be send or received. To enable sending or +receiving broadcast packets use the socket option ``SO_BROADCAST``: + +.. code-block:: C + + int value = 1; + setsockopt(sock, SOL_SOCKET, SO_BROADCAST, &value, sizeof(value)); + +The following diagram illustrates the RX path: + +.. code:: + + +--------------------+ + | incoming packet | + +--------------------+ + | + V + +--------------------+ + | SO_J1939_PROMISC? | + +--------------------+ + | | + no | | yes + | | + .---------' `---------. + | | + +---------------------------+ | + | bind() + connect() + | | + | SOCK_BROADCAST filter | | + +---------------------------+ | + | | + |<---------------------' + V + +---------------------------+ + | SO_J1939_FILTER | + +---------------------------+ + | + V + +---------------------------+ + | socket recv() | + +---------------------------+ + +TX path related options: +``SO_J1939_SEND_PRIO`` - change default send priority for the socket + +Message Flags during send() and Related System Calls +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +``send(2)``, ``sendto(2)`` and ``sendmsg(2)`` take a 'flags' argument. Currently +supported flags are: + +* ``MSG_DONTWAIT``, i.e. non-blocking operation. + +recvmsg(2) +^^^^^^^^^^ + +In most cases ``recvmsg(2)`` is needed if you want to extract more information than +``recvfrom(2)`` can provide. For example package priority and timestamp. The +Destination Address, name and packet priority (if applicable) are attached to +the msghdr in the ``recvmsg(2)`` call. They can be extracted using ``cmsg(3)`` macros, +with ``cmsg_level == SOL_J1939 && cmsg_type == SCM_J1939_DEST_ADDR``, +``SCM_J1939_DEST_NAME`` or ``SCM_J1939_PRIO``. The returned data is a ``uint8_t`` for +``priority`` and ``dst_addr``, and ``uint64_t`` for ``dst_name``. + +.. code-block:: C + + uint8_t priority, dst_addr; + uint64_t dst_name; + + for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) { + switch (cmsg->cmsg_level) { + case SOL_CAN_J1939: + if (cmsg->cmsg_type == SCM_J1939_DEST_ADDR) + dst_addr = *CMSG_DATA(cmsg); + else if (cmsg->cmsg_type == SCM_J1939_DEST_NAME) + memcpy(&dst_name, CMSG_DATA(cmsg), cmsg->cmsg_len - CMSG_LEN(0)); + else if (cmsg->cmsg_type == SCM_J1939_PRIO) + priority = *CMSG_DATA(cmsg); + break; + } + } + +Dynamic Addressing +------------------ + +Distinction has to be made between using the claimed address and doing an +address claim. To use an already claimed address, one has to fill in the +``j1939.name`` member and provide it to ``bind(2)``. If the name had claimed an address +earlier, all further messages being sent will use that address. And the +``j1939.addr`` member will be ignored. + +An exception on this is PGN 0x0ee00. This is the "Address Claim/Cannot Claim +Address" message and the kernel will use the ``j1939.addr`` member for that PGN if +necessary. + +To claim an address following code example can be used: + +.. code-block:: C + + struct sockaddr_can baddr = { + .can_family = AF_CAN, + .can_addr.j1939 = { + .name = name, + .addr = J1939_IDLE_ADDR, + .pgn = J1939_NO_PGN, /* to disable bind() rx filter for PGN */ + }, + .can_ifindex = if_nametoindex("can0"), + }; + + bind(sock, (struct sockaddr *)&baddr, sizeof(baddr)); + + /* for Address Claiming broadcast must be allowed */ + int value = 1; + setsockopt(sock, SOL_SOCKET, SO_BROADCAST, &value, sizeof(value)); + + /* configured advanced RX filter with PGN needed for Address Claiming */ + const struct j1939_filter filt[] = { + { + .pgn = J1939_PGN_ADDRESS_CLAIMED, + .pgn_mask = J1939_PGN_PDU1_MAX, + }, { + .pgn = J1939_PGN_REQUEST, + .pgn_mask = J1939_PGN_PDU1_MAX, + }, { + .pgn = J1939_PGN_ADDRESS_COMMANDED, + .pgn_mask = J1939_PGN_MAX, + }, + }; + + setsockopt(sock, SOL_CAN_J1939, SO_J1939_FILTER, &filt, sizeof(filt)); + + uint64_t dat = htole64(name); + const struct sockaddr_can saddr = { + .can_family = AF_CAN, + .can_addr.j1939 = { + .pgn = J1939_PGN_ADDRESS_CLAIMED, + .addr = J1939_NO_ADDR, + }, + }; + + /* Afterwards do a sendto(2) with data set to the NAME (Little Endian). If the + * NAME provided, does not match the j1939.name provided to bind(2), EPROTO + * will be returned. + */ + sendto(sock, dat, sizeof(dat), 0, (const struct sockaddr *)&saddr, sizeof(saddr)); + +If no-one else contests the address claim within 250ms after transmission, the +kernel marks the NAME-SA assignment as valid. The valid assignment will be kept +among other valid NAME-SA assignments. From that point, any socket bound to the +NAME can send packets. + +If another ECU claims the address, the kernel will mark the NAME-SA expired. +No socket bound to the NAME can send packets (other than address claims). To +claim another address, some socket bound to NAME, must ``bind(2)`` again, but with +only ``j1939.addr`` changed to the new SA, and must then send a valid address claim +packet. This restarts the state machine in the kernel (and any other +participant on the bus) for this NAME. + +``can-utils`` also include the ``j1939acd`` tool, so it can be used as code example or as +default Address Claiming daemon. + +Send Examples +------------- + +Static Addressing +^^^^^^^^^^^^^^^^^ + +This example will send a PGN (0x12300) from SA 0x20 to DA 0x30. + +Bind: + +.. code-block:: C + + struct sockaddr_can baddr = { + .can_family = AF_CAN, + .can_addr.j1939 = { + .name = J1939_NO_NAME, + .addr = 0x20, + .pgn = J1939_NO_PGN, + }, + .can_ifindex = if_nametoindex("can0"), + }; + + bind(sock, (struct sockaddr *)&baddr, sizeof(baddr)); + +Now, the socket 'sock' is bound to the SA 0x20. Since no ``connect(2)`` was called, +at this point we can use only ``sendto(2)`` or ``sendmsg(2)``. + +Send: + +.. code-block:: C + + const struct sockaddr_can saddr = { + .can_family = AF_CAN, + .can_addr.j1939 = { + .name = J1939_NO_NAME; + .addr = 0x30, + .pgn = 0x12300, + }, + }; + + sendto(sock, dat, sizeof(dat), 0, (const struct sockaddr *)&saddr, sizeof(saddr)); diff --git a/Documentation/networking/kapi.rst b/Documentation/networking/kapi.rst new file mode 100644 index 0000000000..ea55f462ce --- /dev/null +++ b/Documentation/networking/kapi.rst @@ -0,0 +1,159 @@ +========================================= +Linux Networking and Network Devices APIs +========================================= + +Linux Networking +================ + +Networking Base Types +--------------------- + +.. kernel-doc:: include/linux/net.h + :internal: + +Socket Buffer Functions +----------------------- + +.. kernel-doc:: include/linux/skbuff.h + :internal: + +.. kernel-doc:: include/net/sock.h + :internal: + +.. kernel-doc:: net/socket.c + :export: + +.. kernel-doc:: net/core/skbuff.c + :export: + +.. kernel-doc:: net/core/sock.c + :export: + +.. kernel-doc:: net/core/datagram.c + :export: + +.. kernel-doc:: net/core/stream.c + :export: + +Socket Filter +------------- + +.. kernel-doc:: net/core/filter.c + :export: + +Generic Network Statistics +-------------------------- + +.. kernel-doc:: include/uapi/linux/gen_stats.h + :internal: + +.. kernel-doc:: net/core/gen_stats.c + :export: + +.. kernel-doc:: net/core/gen_estimator.c + :export: + +SUN RPC subsystem +----------------- + +.. kernel-doc:: net/sunrpc/xdr.c + :export: + +.. kernel-doc:: net/sunrpc/svc_xprt.c + :export: + +.. kernel-doc:: net/sunrpc/xprt.c + :export: + +.. kernel-doc:: net/sunrpc/sched.c + :export: + +.. kernel-doc:: net/sunrpc/socklib.c + :export: + +.. kernel-doc:: net/sunrpc/stats.c + :export: + +.. kernel-doc:: net/sunrpc/rpc_pipe.c + :export: + +.. kernel-doc:: net/sunrpc/rpcb_clnt.c + :export: + +.. kernel-doc:: net/sunrpc/clnt.c + :export: + +Network device support +====================== + +Driver Support +-------------- + +.. kernel-doc:: net/core/dev.c + :export: + +.. kernel-doc:: net/ethernet/eth.c + :export: + +.. kernel-doc:: net/sched/sch_generic.c + :export: + +.. kernel-doc:: include/linux/etherdevice.h + :internal: + +.. kernel-doc:: include/linux/netdevice.h + :internal: + +PHY Support +----------- + +.. kernel-doc:: drivers/net/phy/phy.c + :export: + +.. kernel-doc:: drivers/net/phy/phy.c + :internal: + +.. kernel-doc:: drivers/net/phy/phy-core.c + :export: + +.. kernel-doc:: drivers/net/phy/phy-c45.c + :export: + +.. kernel-doc:: include/linux/phy.h + :internal: + +.. kernel-doc:: drivers/net/phy/phy_device.c + :export: + +.. kernel-doc:: drivers/net/phy/phy_device.c + :internal: + +.. kernel-doc:: drivers/net/phy/mdio_bus.c + :export: + +.. kernel-doc:: drivers/net/phy/mdio_bus.c + :internal: + +PHYLINK +------- + + PHYLINK interfaces traditional network drivers with PHYLIB, fixed-links, + and SFF modules (eg, hot-pluggable SFP) that may contain PHYs. PHYLINK + provides management of the link state and link modes. + +.. kernel-doc:: include/linux/phylink.h + :internal: + +.. kernel-doc:: drivers/net/phy/phylink.c + +SFP support +----------- + +.. kernel-doc:: drivers/net/phy/sfp-bus.c + :internal: + +.. kernel-doc:: include/linux/sfp.h + :internal: + +.. kernel-doc:: drivers/net/phy/sfp-bus.c + :export: diff --git a/Documentation/networking/kcm.rst b/Documentation/networking/kcm.rst new file mode 100644 index 0000000000..db0f5560ac --- /dev/null +++ b/Documentation/networking/kcm.rst @@ -0,0 +1,290 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================= +Kernel Connection Multiplexor +============================= + +Kernel Connection Multiplexor (KCM) is a mechanism that provides a message based +interface over TCP for generic application protocols. With KCM an application +can efficiently send and receive application protocol messages over TCP using +datagram sockets. + +KCM implements an NxM multiplexor in the kernel as diagrammed below:: + + +------------+ +------------+ +------------+ +------------+ + | KCM socket | | KCM socket | | KCM socket | | KCM socket | + +------------+ +------------+ +------------+ +------------+ + | | | | + +-----------+ | | +----------+ + | | | | + +----------------------------------+ + | Multiplexor | + +----------------------------------+ + | | | | | + +---------+ | | | ------------+ + | | | | | + +----------+ +----------+ +----------+ +----------+ +----------+ + | Psock | | Psock | | Psock | | Psock | | Psock | + +----------+ +----------+ +----------+ +----------+ +----------+ + | | | | | + +----------+ +----------+ +----------+ +----------+ +----------+ + | TCP sock | | TCP sock | | TCP sock | | TCP sock | | TCP sock | + +----------+ +----------+ +----------+ +----------+ +----------+ + +KCM sockets +=========== + +The KCM sockets provide the user interface to the multiplexor. All the KCM sockets +bound to a multiplexor are considered to have equivalent function, and I/O +operations in different sockets may be done in parallel without the need for +synchronization between threads in userspace. + +Multiplexor +=========== + +The multiplexor provides the message steering. In the transmit path, messages +written on a KCM socket are sent atomically on an appropriate TCP socket. +Similarly, in the receive path, messages are constructed on each TCP socket +(Psock) and complete messages are steered to a KCM socket. + +TCP sockets & Psocks +==================== + +TCP sockets may be bound to a KCM multiplexor. A Psock structure is allocated +for each bound TCP socket, this structure holds the state for constructing +messages on receive as well as other connection specific information for KCM. + +Connected mode semantics +======================== + +Each multiplexor assumes that all attached TCP connections are to the same +destination and can use the different connections for load balancing when +transmitting. The normal send and recv calls (include sendmmsg and recvmmsg) +can be used to send and receive messages from the KCM socket. + +Socket types +============ + +KCM supports SOCK_DGRAM and SOCK_SEQPACKET socket types. + +Message delineation +------------------- + +Messages are sent over a TCP stream with some application protocol message +format that typically includes a header which frames the messages. The length +of a received message can be deduced from the application protocol header +(often just a simple length field). + +A TCP stream must be parsed to determine message boundaries. Berkeley Packet +Filter (BPF) is used for this. When attaching a TCP socket to a multiplexor a +BPF program must be specified. The program is called at the start of receiving +a new message and is given an skbuff that contains the bytes received so far. +It parses the message header and returns the length of the message. Given this +information, KCM will construct the message of the stated length and deliver it +to a KCM socket. + +TCP socket management +--------------------- + +When a TCP socket is attached to a KCM multiplexor data ready (POLLIN) and +write space available (POLLOUT) events are handled by the multiplexor. If there +is a state change (disconnection) or other error on a TCP socket, an error is +posted on the TCP socket so that a POLLERR event happens and KCM discontinues +using the socket. When the application gets the error notification for a +TCP socket, it should unattach the socket from KCM and then handle the error +condition (the typical response is to close the socket and create a new +connection if necessary). + +KCM limits the maximum receive message size to be the size of the receive +socket buffer on the attached TCP socket (the socket buffer size can be set by +SO_RCVBUF). If the length of a new message reported by the BPF program is +greater than this limit a corresponding error (EMSGSIZE) is posted on the TCP +socket. The BPF program may also enforce a maximum messages size and report an +error when it is exceeded. + +A timeout may be set for assembling messages on a receive socket. The timeout +value is taken from the receive timeout of the attached TCP socket (this is set +by SO_RCVTIMEO). If the timer expires before assembly is complete an error +(ETIMEDOUT) is posted on the socket. + +User interface +============== + +Creating a multiplexor +---------------------- + +A new multiplexor and initial KCM socket is created by a socket call:: + + socket(AF_KCM, type, protocol) + +- type is either SOCK_DGRAM or SOCK_SEQPACKET +- protocol is KCMPROTO_CONNECTED + +Cloning KCM sockets +------------------- + +After the first KCM socket is created using the socket call as described +above, additional sockets for the multiplexor can be created by cloning +a KCM socket. This is accomplished by an ioctl on a KCM socket:: + + /* From linux/kcm.h */ + struct kcm_clone { + int fd; + }; + + struct kcm_clone info; + + memset(&info, 0, sizeof(info)); + + err = ioctl(kcmfd, SIOCKCMCLONE, &info); + + if (!err) + newkcmfd = info.fd; + +Attach transport sockets +------------------------ + +Attaching of transport sockets to a multiplexor is performed by calling an +ioctl on a KCM socket for the multiplexor. e.g.:: + + /* From linux/kcm.h */ + struct kcm_attach { + int fd; + int bpf_fd; + }; + + struct kcm_attach info; + + memset(&info, 0, sizeof(info)); + + info.fd = tcpfd; + info.bpf_fd = bpf_prog_fd; + + ioctl(kcmfd, SIOCKCMATTACH, &info); + +The kcm_attach structure contains: + + - fd: file descriptor for TCP socket being attached + - bpf_prog_fd: file descriptor for compiled BPF program downloaded + +Unattach transport sockets +-------------------------- + +Unattaching a transport socket from a multiplexor is straightforward. An +"unattach" ioctl is done with the kcm_unattach structure as the argument:: + + /* From linux/kcm.h */ + struct kcm_unattach { + int fd; + }; + + struct kcm_unattach info; + + memset(&info, 0, sizeof(info)); + + info.fd = cfd; + + ioctl(fd, SIOCKCMUNATTACH, &info); + +Disabling receive on KCM socket +------------------------------- + +A setsockopt is used to disable or enable receiving on a KCM socket. +When receive is disabled, any pending messages in the socket's +receive buffer are moved to other sockets. This feature is useful +if an application thread knows that it will be doing a lot of +work on a request and won't be able to service new messages for a +while. Example use:: + + int val = 1; + + setsockopt(kcmfd, SOL_KCM, KCM_RECV_DISABLE, &val, sizeof(val)) + +BFP programs for message delineation +------------------------------------ + +BPF programs can be compiled using the BPF LLVM backend. For example, +the BPF program for parsing Thrift is:: + + #include "bpf.h" /* for __sk_buff */ + #include "bpf_helpers.h" /* for load_word intrinsic */ + + SEC("socket_kcm") + int bpf_prog1(struct __sk_buff *skb) + { + return load_word(skb, 0) + 4; + } + + char _license[] SEC("license") = "GPL"; + +Use in applications +=================== + +KCM accelerates application layer protocols. Specifically, it allows +applications to use a message based interface for sending and receiving +messages. The kernel provides necessary assurances that messages are sent +and received atomically. This relieves much of the burden applications have +in mapping a message based protocol onto the TCP stream. KCM also make +application layer messages a unit of work in the kernel for the purposes of +steering and scheduling, which in turn allows a simpler networking model in +multithreaded applications. + +Configurations +-------------- + +In an Nx1 configuration, KCM logically provides multiple socket handles +to the same TCP connection. This allows parallelism between in I/O +operations on the TCP socket (for instance copyin and copyout of data is +parallelized). In an application, a KCM socket can be opened for each +processing thread and inserted into the epoll (similar to how SO_REUSEPORT +is used to allow multiple listener sockets on the same port). + +In a MxN configuration, multiple connections are established to the +same destination. These are used for simple load balancing. + +Message batching +---------------- + +The primary purpose of KCM is load balancing between KCM sockets and hence +threads in a nominal use case. Perfect load balancing, that is steering +each received message to a different KCM socket or steering each sent +message to a different TCP socket, can negatively impact performance +since this doesn't allow for affinities to be established. Balancing +based on groups, or batches of messages, can be beneficial for performance. + +On transmit, there are three ways an application can batch (pipeline) +messages on a KCM socket. + + 1) Send multiple messages in a single sendmmsg. + 2) Send a group of messages each with a sendmsg call, where all messages + except the last have MSG_BATCH in the flags of sendmsg call. + 3) Create "super message" composed of multiple messages and send this + with a single sendmsg. + +On receive, the KCM module attempts to queue messages received on the +same KCM socket during each TCP ready callback. The targeted KCM socket +changes at each receive ready callback on the KCM socket. The application +does not need to configure this. + +Error handling +-------------- + +An application should include a thread to monitor errors raised on +the TCP connection. Normally, this will be done by placing each +TCP socket attached to a KCM multiplexor in epoll set for POLLERR +event. If an error occurs on an attached TCP socket, KCM sets an EPIPE +on the socket thus waking up the application thread. When the application +sees the error (which may just be a disconnect) it should unattach the +socket from KCM and then close it. It is assumed that once an error is +posted on the TCP socket the data stream is unrecoverable (i.e. an error +may have occurred in the middle of receiving a message). + +TCP connection monitoring +------------------------- + +In KCM there is no means to correlate a message to the TCP socket that +was used to send or receive the message (except in the case there is +only one attached TCP socket). However, the application does retain +an open file descriptor to the socket so it will be able to get statistics +from the socket which can be used in detecting issues (such as high +retransmissions on the socket). diff --git a/Documentation/networking/l2tp.rst b/Documentation/networking/l2tp.rst new file mode 100644 index 0000000000..7f383e99db --- /dev/null +++ b/Documentation/networking/l2tp.rst @@ -0,0 +1,677 @@ +.. SPDX-License-Identifier: GPL-2.0 + +==== +L2TP +==== + +Layer 2 Tunneling Protocol (L2TP) allows L2 frames to be tunneled over +an IP network. + +This document covers the kernel's L2TP subsystem. It documents kernel +APIs for application developers who want to use the L2TP subsystem and +it provides some technical details about the internal implementation +which may be useful to kernel developers and maintainers. + +Overview +======== + +The kernel's L2TP subsystem implements the datapath for L2TPv2 and +L2TPv3. L2TPv2 is carried over UDP. L2TPv3 is carried over UDP or +directly over IP (protocol 115). + +The L2TP RFCs define two basic kinds of L2TP packets: control packets +(the "control plane"), and data packets (the "data plane"). The kernel +deals only with data packets. The more complex control packets are +handled by user space. + +An L2TP tunnel carries one or more L2TP sessions. Each tunnel is +associated with a socket. Each session is associated with a virtual +netdevice, e.g. ``pppN``, ``l2tpethN``, through which data frames pass +to/from L2TP. Fields in the L2TP header identify the tunnel or session +and whether it is a control or data packet. When tunnels and sessions +are set up using the Linux kernel API, we're just setting up the L2TP +data path. All aspects of the control protocol are to be handled by +user space. + +This split in responsibilities leads to a natural sequence of +operations when establishing tunnels and sessions. The procedure looks +like this: + + 1) Create a tunnel socket. Exchange L2TP control protocol messages + with the peer over that socket in order to establish a tunnel. + + 2) Create a tunnel context in the kernel, using information + obtained from the peer using the control protocol messages. + + 3) Exchange L2TP control protocol messages with the peer over the + tunnel socket in order to establish a session. + + 4) Create a session context in the kernel using information + obtained from the peer using the control protocol messages. + +L2TP APIs +========= + +This section documents each userspace API of the L2TP subsystem. + +Tunnel Sockets +-------------- + +L2TPv2 always uses UDP. L2TPv3 may use UDP or IP encapsulation. + +To create a tunnel socket for use by L2TP, the standard POSIX +socket API is used. + +For example, for a tunnel using IPv4 addresses and UDP encapsulation:: + + int sockfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); + +Or for a tunnel using IPv6 addresses and IP encapsulation:: + + int sockfd = socket(AF_INET6, SOCK_DGRAM, IPPROTO_L2TP); + +UDP socket programming doesn't need to be covered here. + +IPPROTO_L2TP is an IP protocol type implemented by the kernel's L2TP +subsystem. The L2TPIP socket address is defined in struct +sockaddr_l2tpip and struct sockaddr_l2tpip6 at +`include/uapi/linux/l2tp.h`_. The address includes the L2TP tunnel +(connection) id. To use L2TP IP encapsulation, an L2TPv3 application +should bind the L2TPIP socket using the locally assigned +tunnel id. When the peer's tunnel id and IP address is known, a +connect must be done. + +If the L2TP application needs to handle L2TPv3 tunnel setup requests +from peers using L2TPIP, it must open a dedicated L2TPIP +socket to listen for those requests and bind the socket using tunnel +id 0 since tunnel setup requests are addressed to tunnel id 0. + +An L2TP tunnel and all of its sessions are automatically closed when +its tunnel socket is closed. + +Netlink API +----------- + +L2TP applications use netlink to manage L2TP tunnel and session +instances in the kernel. The L2TP netlink API is defined in +`include/uapi/linux/l2tp.h`_. + +L2TP uses `Generic Netlink`_ (GENL). Several commands are defined: +Create, Delete, Modify and Get for tunnel and session +instances, e.g. ``L2TP_CMD_TUNNEL_CREATE``. The API header lists the +netlink attribute types that can be used with each command. + +Tunnel and session instances are identified by a locally unique +32-bit id. L2TP tunnel ids are given by ``L2TP_ATTR_CONN_ID`` and +``L2TP_ATTR_PEER_CONN_ID`` attributes and L2TP session ids are given +by ``L2TP_ATTR_SESSION_ID`` and ``L2TP_ATTR_PEER_SESSION_ID`` +attributes. If netlink is used to manage L2TPv2 tunnel and session +instances, the L2TPv2 16-bit tunnel/session id is cast to a 32-bit +value in these attributes. + +In the ``L2TP_CMD_TUNNEL_CREATE`` command, ``L2TP_ATTR_FD`` tells the +kernel the tunnel socket fd being used. If not specified, the kernel +creates a kernel socket for the tunnel, using IP parameters set in +``L2TP_ATTR_IP[6]_SADDR``, ``L2TP_ATTR_IP[6]_DADDR``, +``L2TP_ATTR_UDP_SPORT``, ``L2TP_ATTR_UDP_DPORT`` attributes. Kernel +sockets are used to implement unmanaged L2TPv3 tunnels (iproute2's "ip +l2tp" commands). If ``L2TP_ATTR_FD`` is given, it must be a socket fd +that is already bound and connected. There is more information about +unmanaged tunnels later in this document. + +``L2TP_CMD_TUNNEL_CREATE`` attributes:- + +================== ======== === +Attribute Required Use +================== ======== === +CONN_ID Y Sets the tunnel (connection) id. +PEER_CONN_ID Y Sets the peer tunnel (connection) id. +PROTO_VERSION Y Protocol version. 2 or 3. +ENCAP_TYPE Y Encapsulation type: UDP or IP. +FD N Tunnel socket file descriptor. +UDP_CSUM N Enable IPv4 UDP checksums. Used only if FD is + not set. +UDP_ZERO_CSUM6_TX N Zero IPv6 UDP checksum on transmit. Used only + if FD is not set. +UDP_ZERO_CSUM6_RX N Zero IPv6 UDP checksum on receive. Used only if + FD is not set. +IP_SADDR N IPv4 source address. Used only if FD is not + set. +IP_DADDR N IPv4 destination address. Used only if FD is + not set. +UDP_SPORT N UDP source port. Used only if FD is not set. +UDP_DPORT N UDP destination port. Used only if FD is not + set. +IP6_SADDR N IPv6 source address. Used only if FD is not + set. +IP6_DADDR N IPv6 destination address. Used only if FD is + not set. +DEBUG N Debug flags. +================== ======== === + +``L2TP_CMD_TUNNEL_DESTROY`` attributes:- + +================== ======== === +Attribute Required Use +================== ======== === +CONN_ID Y Identifies the tunnel id to be destroyed. +================== ======== === + +``L2TP_CMD_TUNNEL_MODIFY`` attributes:- + +================== ======== === +Attribute Required Use +================== ======== === +CONN_ID Y Identifies the tunnel id to be modified. +DEBUG N Debug flags. +================== ======== === + +``L2TP_CMD_TUNNEL_GET`` attributes:- + +================== ======== === +Attribute Required Use +================== ======== === +CONN_ID N Identifies the tunnel id to be queried. + Ignored in DUMP requests. +================== ======== === + +``L2TP_CMD_SESSION_CREATE`` attributes:- + +================== ======== === +Attribute Required Use +================== ======== === +CONN_ID Y The parent tunnel id. +SESSION_ID Y Sets the session id. +PEER_SESSION_ID Y Sets the parent session id. +PW_TYPE Y Sets the pseudowire type. +DEBUG N Debug flags. +RECV_SEQ N Enable rx data sequence numbers. +SEND_SEQ N Enable tx data sequence numbers. +LNS_MODE N Enable LNS mode (auto-enable data sequence + numbers). +RECV_TIMEOUT N Timeout to wait when reordering received + packets. +L2SPEC_TYPE N Sets layer2-specific-sublayer type (L2TPv3 + only). +COOKIE N Sets optional cookie (L2TPv3 only). +PEER_COOKIE N Sets optional peer cookie (L2TPv3 only). +IFNAME N Sets interface name (L2TPv3 only). +================== ======== === + +For Ethernet session types, this will create an l2tpeth virtual +interface which can then be configured as required. For PPP session +types, a PPPoL2TP socket must also be opened and connected, mapping it +onto the new session. This is covered in "PPPoL2TP Sockets" later. + +``L2TP_CMD_SESSION_DESTROY`` attributes:- + +================== ======== === +Attribute Required Use +================== ======== === +CONN_ID Y Identifies the parent tunnel id of the session + to be destroyed. +SESSION_ID Y Identifies the session id to be destroyed. +IFNAME N Identifies the session by interface name. If + set, this overrides any CONN_ID and SESSION_ID + attributes. Currently supported for L2TPv3 + Ethernet sessions only. +================== ======== === + +``L2TP_CMD_SESSION_MODIFY`` attributes:- + +================== ======== === +Attribute Required Use +================== ======== === +CONN_ID Y Identifies the parent tunnel id of the session + to be modified. +SESSION_ID Y Identifies the session id to be modified. +IFNAME N Identifies the session by interface name. If + set, this overrides any CONN_ID and SESSION_ID + attributes. Currently supported for L2TPv3 + Ethernet sessions only. +DEBUG N Debug flags. +RECV_SEQ N Enable rx data sequence numbers. +SEND_SEQ N Enable tx data sequence numbers. +LNS_MODE N Enable LNS mode (auto-enable data sequence + numbers). +RECV_TIMEOUT N Timeout to wait when reordering received + packets. +================== ======== === + +``L2TP_CMD_SESSION_GET`` attributes:- + +================== ======== === +Attribute Required Use +================== ======== === +CONN_ID N Identifies the tunnel id to be queried. + Ignored for DUMP requests. +SESSION_ID N Identifies the session id to be queried. + Ignored for DUMP requests. +IFNAME N Identifies the session by interface name. + If set, this overrides any CONN_ID and + SESSION_ID attributes. Ignored for DUMP + requests. Currently supported for L2TPv3 + Ethernet sessions only. +================== ======== === + +Application developers should refer to `include/uapi/linux/l2tp.h`_ for +netlink command and attribute definitions. + +Sample userspace code using libmnl_: + + - Open L2TP netlink socket:: + + struct nl_sock *nl_sock; + int l2tp_nl_family_id; + + nl_sock = nl_socket_alloc(); + genl_connect(nl_sock); + genl_id = genl_ctrl_resolve(nl_sock, L2TP_GENL_NAME); + + - Create a tunnel:: + + struct nlmsghdr *nlh; + struct genlmsghdr *gnlh; + + nlh = mnl_nlmsg_put_header(buf); + nlh->nlmsg_type = genl_id; /* assigned to genl socket */ + nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK; + nlh->nlmsg_seq = seq; + + gnlh = mnl_nlmsg_put_extra_header(nlh, sizeof(*gnlh)); + gnlh->cmd = L2TP_CMD_TUNNEL_CREATE; + gnlh->version = L2TP_GENL_VERSION; + gnlh->reserved = 0; + + mnl_attr_put_u32(nlh, L2TP_ATTR_FD, tunl_sock_fd); + mnl_attr_put_u32(nlh, L2TP_ATTR_CONN_ID, tid); + mnl_attr_put_u32(nlh, L2TP_ATTR_PEER_CONN_ID, peer_tid); + mnl_attr_put_u8(nlh, L2TP_ATTR_PROTO_VERSION, protocol_version); + mnl_attr_put_u16(nlh, L2TP_ATTR_ENCAP_TYPE, encap); + + - Create a session:: + + struct nlmsghdr *nlh; + struct genlmsghdr *gnlh; + + nlh = mnl_nlmsg_put_header(buf); + nlh->nlmsg_type = genl_id; /* assigned to genl socket */ + nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK; + nlh->nlmsg_seq = seq; + + gnlh = mnl_nlmsg_put_extra_header(nlh, sizeof(*gnlh)); + gnlh->cmd = L2TP_CMD_SESSION_CREATE; + gnlh->version = L2TP_GENL_VERSION; + gnlh->reserved = 0; + + mnl_attr_put_u32(nlh, L2TP_ATTR_CONN_ID, tid); + mnl_attr_put_u32(nlh, L2TP_ATTR_PEER_CONN_ID, peer_tid); + mnl_attr_put_u32(nlh, L2TP_ATTR_SESSION_ID, sid); + mnl_attr_put_u32(nlh, L2TP_ATTR_PEER_SESSION_ID, peer_sid); + mnl_attr_put_u16(nlh, L2TP_ATTR_PW_TYPE, pwtype); + /* there are other session options which can be set using netlink + * attributes during session creation -- see l2tp.h + */ + + - Delete a session:: + + struct nlmsghdr *nlh; + struct genlmsghdr *gnlh; + + nlh = mnl_nlmsg_put_header(buf); + nlh->nlmsg_type = genl_id; /* assigned to genl socket */ + nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK; + nlh->nlmsg_seq = seq; + + gnlh = mnl_nlmsg_put_extra_header(nlh, sizeof(*gnlh)); + gnlh->cmd = L2TP_CMD_SESSION_DELETE; + gnlh->version = L2TP_GENL_VERSION; + gnlh->reserved = 0; + + mnl_attr_put_u32(nlh, L2TP_ATTR_CONN_ID, tid); + mnl_attr_put_u32(nlh, L2TP_ATTR_SESSION_ID, sid); + + - Delete a tunnel and all of its sessions (if any):: + + struct nlmsghdr *nlh; + struct genlmsghdr *gnlh; + + nlh = mnl_nlmsg_put_header(buf); + nlh->nlmsg_type = genl_id; /* assigned to genl socket */ + nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK; + nlh->nlmsg_seq = seq; + + gnlh = mnl_nlmsg_put_extra_header(nlh, sizeof(*gnlh)); + gnlh->cmd = L2TP_CMD_TUNNEL_DELETE; + gnlh->version = L2TP_GENL_VERSION; + gnlh->reserved = 0; + + mnl_attr_put_u32(nlh, L2TP_ATTR_CONN_ID, tid); + +PPPoL2TP Session Socket API +--------------------------- + +For PPP session types, a PPPoL2TP socket must be opened and connected +to the L2TP session. + +When creating PPPoL2TP sockets, the application provides information +to the kernel about the tunnel and session in a socket connect() +call. Source and destination tunnel and session ids are provided, as +well as the file descriptor of a UDP or L2TPIP socket. See struct +pppol2tp_addr in `include/linux/if_pppol2tp.h`_. For historical reasons, +there are unfortunately slightly different address structures for +L2TPv2/L2TPv3 IPv4/IPv6 tunnels and userspace must use the appropriate +structure that matches the tunnel socket type. + +Userspace may control behavior of the tunnel or session using +setsockopt and ioctl on the PPPoX socket. The following socket +options are supported:- + +========= =========================================================== +DEBUG bitmask of debug message categories. See below. +SENDSEQ - 0 => don't send packets with sequence numbers + - 1 => send packets with sequence numbers +RECVSEQ - 0 => receive packet sequence numbers are optional + - 1 => drop receive packets without sequence numbers +LNSMODE - 0 => act as LAC. + - 1 => act as LNS. +REORDERTO reorder timeout (in millisecs). If 0, don't try to reorder. +========= =========================================================== + +In addition to the standard PPP ioctls, a PPPIOCGL2TPSTATS is provided +to retrieve tunnel and session statistics from the kernel using the +PPPoX socket of the appropriate tunnel or session. + +Sample userspace code: + + - Create session PPPoX data socket:: + + struct sockaddr_pppol2tp sax; + int fd; + + /* Note, the tunnel socket must be bound already, else it + * will not be ready + */ + sax.sa_family = AF_PPPOX; + sax.sa_protocol = PX_PROTO_OL2TP; + sax.pppol2tp.fd = tunnel_fd; + sax.pppol2tp.addr.sin_addr.s_addr = addr->sin_addr.s_addr; + sax.pppol2tp.addr.sin_port = addr->sin_port; + sax.pppol2tp.addr.sin_family = AF_INET; + sax.pppol2tp.s_tunnel = tunnel_id; + sax.pppol2tp.s_session = session_id; + sax.pppol2tp.d_tunnel = peer_tunnel_id; + sax.pppol2tp.d_session = peer_session_id; + + /* session_fd is the fd of the session's PPPoL2TP socket. + * tunnel_fd is the fd of the tunnel UDP / L2TPIP socket. + */ + fd = connect(session_fd, (struct sockaddr *)&sax, sizeof(sax)); + if (fd < 0 ) { + return -errno; + } + return 0; + +Old L2TPv2-only API +------------------- + +When L2TP was first added to the Linux kernel in 2.6.23, it +implemented only L2TPv2 and did not include a netlink API. Instead, +tunnel and session instances in the kernel were managed directly using +only PPPoL2TP sockets. The PPPoL2TP socket is used as described in +section "PPPoL2TP Session Socket API" but tunnel and session instances +are automatically created on a connect() of the socket instead of +being created by a separate netlink request: + + - Tunnels are managed using a tunnel management socket which is a + dedicated PPPoL2TP socket, connected to (invalid) session + id 0. The L2TP tunnel instance is created when the PPPoL2TP + tunnel management socket is connected and is destroyed when the + socket is closed. + + - Session instances are created in the kernel when a PPPoL2TP + socket is connected to a non-zero session id. Session parameters + are set using setsockopt. The L2TP session instance is destroyed + when the socket is closed. + +This API is still supported but its use is discouraged. Instead, new +L2TPv2 applications should use netlink to first create the tunnel and +session, then create a PPPoL2TP socket for the session. + +Unmanaged L2TPv3 tunnels +------------------------ + +The kernel L2TP subsystem also supports static (unmanaged) L2TPv3 +tunnels. Unmanaged tunnels have no userspace tunnel socket, and +exchange no control messages with the peer to set up the tunnel; the +tunnel is configured manually at each end of the tunnel. All +configuration is done using netlink. There is no need for an L2TP +userspace application in this case -- the tunnel socket is created by +the kernel and configured using parameters sent in the +``L2TP_CMD_TUNNEL_CREATE`` netlink request. The ``ip`` utility of +``iproute2`` has commands for managing static L2TPv3 tunnels; do ``ip +l2tp help`` for more information. + +Debugging +--------- + +The L2TP subsystem offers a range of debugging interfaces through the +debugfs filesystem. + +To access these interfaces, the debugfs filesystem must first be mounted:: + + # mount -t debugfs debugfs /debug + +Files under the l2tp directory can then be accessed, providing a summary +of the current population of tunnel and session contexts existing in the +kernel:: + + # cat /debug/l2tp/tunnels + +The debugfs files should not be used by applications to obtain L2TP +state information because the file format is subject to change. It is +implemented to provide extra debug information to help diagnose +problems. Applications should instead use the netlink API. + +In addition the L2TP subsystem implements tracepoints using the standard +kernel event tracing API. The available L2TP events can be reviewed as +follows:: + + # find /debug/tracing/events/l2tp + +Finally, /proc/net/pppol2tp is also provided for backwards compatibility +with the original pppol2tp code. It lists information about L2TPv2 +tunnels and sessions only. Its use is discouraged. + +Internal Implementation +======================= + +This section is for kernel developers and maintainers. + +Sockets +------- + +UDP sockets are implemented by the networking core. When an L2TP +tunnel is created using a UDP socket, the socket is set up as an +encapsulated UDP socket by setting encap_rcv and encap_destroy +callbacks on the UDP socket. l2tp_udp_encap_recv is called when +packets are received on the socket. l2tp_udp_encap_destroy is called +when userspace closes the socket. + +L2TPIP sockets are implemented in `net/l2tp/l2tp_ip.c`_ and +`net/l2tp/l2tp_ip6.c`_. + +Tunnels +------- + +The kernel keeps a struct l2tp_tunnel context per L2TP tunnel. The +l2tp_tunnel is always associated with a UDP or L2TP/IP socket and +keeps a list of sessions in the tunnel. When a tunnel is first +registered with L2TP core, the reference count on the socket is +increased. This ensures that the socket cannot be removed while L2TP's +data structures reference it. + +Tunnels are identified by a unique tunnel id. The id is 16-bit for +L2TPv2 and 32-bit for L2TPv3. Internally, the id is stored as a 32-bit +value. + +Tunnels are kept in a per-net list, indexed by tunnel id. The tunnel +id namespace is shared by L2TPv2 and L2TPv3. The tunnel context can be +derived from the socket's sk_user_data. + +Handling tunnel socket close is perhaps the most tricky part of the +L2TP implementation. If userspace closes a tunnel socket, the L2TP +tunnel and all of its sessions must be closed and destroyed. Since the +tunnel context holds a ref on the tunnel socket, the socket's +sk_destruct won't be called until the tunnel sock_put's its +socket. For UDP sockets, when userspace closes the tunnel socket, the +socket's encap_destroy handler is invoked, which L2TP uses to initiate +its tunnel close actions. For L2TPIP sockets, the socket's close +handler initiates the same tunnel close actions. All sessions are +first closed. Each session drops its tunnel ref. When the tunnel ref +reaches zero, the tunnel puts its socket ref. When the socket is +eventually destroyed, its sk_destruct finally frees the L2TP tunnel +context. + +Sessions +-------- + +The kernel keeps a struct l2tp_session context for each session. Each +session has private data which is used for data specific to the +session type. With L2TPv2, the session always carries PPP +traffic. With L2TPv3, the session can carry Ethernet frames (Ethernet +pseudowire) or other data types such as PPP, ATM, HDLC or Frame +Relay. Linux currently implements only Ethernet and PPP session types. + +Some L2TP session types also have a socket (PPP pseudowires) while +others do not (Ethernet pseudowires). We can't therefore use the +socket reference count as the reference count for session +contexts. The L2TP implementation therefore has its own internal +reference counts on the session contexts. + +Like tunnels, L2TP sessions are identified by a unique +session id. Just as with tunnel ids, the session id is 16-bit for +L2TPv2 and 32-bit for L2TPv3. Internally, the id is stored as a 32-bit +value. + +Sessions hold a ref on their parent tunnel to ensure that the tunnel +stays extant while one or more sessions references it. + +Sessions are kept in a per-tunnel list, indexed by session id. L2TPv3 +sessions are also kept in a per-net list indexed by session id, +because L2TPv3 session ids are unique across all tunnels and L2TPv3 +data packets do not contain a tunnel id in the header. This list is +therefore needed to find the session context associated with a +received data packet when the tunnel context cannot be derived from +the tunnel socket. + +Although the L2TPv3 RFC specifies that L2TPv3 session ids are not +scoped by the tunnel, the kernel does not police this for L2TPv3 UDP +tunnels and does not add sessions of L2TPv3 UDP tunnels into the +per-net session list. In the UDP receive code, we must trust that the +tunnel can be identified using the tunnel socket's sk_user_data and +lookup the session in the tunnel's session list instead of the per-net +session list. + +PPP +--- + +`net/l2tp/l2tp_ppp.c`_ implements the PPPoL2TP socket family. Each PPP +session has a PPPoL2TP socket. + +The PPPoL2TP socket's sk_user_data references the l2tp_session. + +Userspace sends and receives PPP packets over L2TP using a PPPoL2TP +socket. Only PPP control frames pass over this socket: PPP data +packets are handled entirely by the kernel, passing between the L2TP +session and its associated ``pppN`` netdev through the PPP channel +interface of the kernel PPP subsystem. + +The L2TP PPP implementation handles the closing of a PPPoL2TP socket +by closing its corresponding L2TP session. This is complicated because +it must consider racing with netlink session create/destroy requests +and pppol2tp_connect trying to reconnect with a session that is in the +process of being closed. Unlike tunnels, PPP sessions do not hold a +ref on their associated socket, so code must be careful to sock_hold +the socket where necessary. For all the details, see commit +3d609342cc04129ff7568e19316ce3d7451a27e8. + +Ethernet +-------- + +`net/l2tp/l2tp_eth.c`_ implements L2TPv3 Ethernet pseudowires. It +manages a netdev for each session. + +L2TP Ethernet sessions are created and destroyed by netlink request, +or are destroyed when the tunnel is destroyed. Unlike PPP sessions, +Ethernet sessions do not have an associated socket. + +Miscellaneous +============= + +RFCs +---- + +The kernel code implements the datapath features specified in the +following RFCs: + +======= =============== =================================== +RFC2661 L2TPv2 https://tools.ietf.org/html/rfc2661 +RFC3931 L2TPv3 https://tools.ietf.org/html/rfc3931 +RFC4719 L2TPv3 Ethernet https://tools.ietf.org/html/rfc4719 +======= =============== =================================== + +Implementations +--------------- + +A number of open source applications use the L2TP kernel subsystem: + +============ ============================================== +iproute2 https://github.com/shemminger/iproute2 +go-l2tp https://github.com/katalix/go-l2tp +tunneldigger https://github.com/wlanslovenija/tunneldigger +xl2tpd https://github.com/xelerance/xl2tpd +============ ============================================== + +Limitations +----------- + +The current implementation has a number of limitations: + + 1) Multiple UDP sockets with the same 5-tuple address cannot be + used. The kernel's tunnel context is identified using private + data associated with the socket so it is important that each + socket is uniquely identified by its address. + + 2) Interfacing with openvswitch is not yet implemented. It may be + useful to map OVS Ethernet and VLAN ports into L2TPv3 tunnels. + + 3) VLAN pseudowires are implemented using an ``l2tpethN`` interface + configured with a VLAN sub-interface. Since L2TPv3 VLAN + pseudowires carry one and only one VLAN, it may be better to use + a single netdevice rather than an ``l2tpethN`` and ``l2tpethN``:M + pair per VLAN session. The netlink attribute + ``L2TP_ATTR_VLAN_ID`` was added for this, but it was never + implemented. + +Testing +------- + +Unmanaged L2TPv3 Ethernet features are tested by the kernel's built-in +selftests. See `tools/testing/selftests/net/l2tp.sh`_. + +Another test suite, l2tp-ktest_, covers all +of the L2TP APIs and tunnel/session types. This may be integrated into +the kernel's built-in L2TP selftests in the future. + +.. Links +.. _Generic Netlink: generic_netlink.html +.. _libmnl: https://www.netfilter.org/projects/libmnl +.. _include/uapi/linux/l2tp.h: ../../../include/uapi/linux/l2tp.h +.. _include/linux/if_pppol2tp.h: ../../../include/linux/if_pppol2tp.h +.. _net/l2tp/l2tp_ip.c: ../../../net/l2tp/l2tp_ip.c +.. _net/l2tp/l2tp_ip6.c: ../../../net/l2tp/l2tp_ip6.c +.. _net/l2tp/l2tp_ppp.c: ../../../net/l2tp/l2tp_ppp.c +.. _net/l2tp/l2tp_eth.c: ../../../net/l2tp/l2tp_eth.c +.. _tools/testing/selftests/net/l2tp.sh: ../../../tools/testing/selftests/net/l2tp.sh +.. _l2tp-ktest: https://github.com/katalix/l2tp-ktest diff --git a/Documentation/networking/lapb-module.rst b/Documentation/networking/lapb-module.rst new file mode 100644 index 0000000000..ff586bc9f0 --- /dev/null +++ b/Documentation/networking/lapb-module.rst @@ -0,0 +1,305 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=============================== +The Linux LAPB Module Interface +=============================== + +Version 1.3 + +Jonathan Naylor 29.12.96 + +Changed (Henner Eisen, 2000-10-29): int return value for data_indication() + +The LAPB module will be a separately compiled module for use by any parts of +the Linux operating system that require a LAPB service. This document +defines the interfaces to, and the services provided by this module. The +term module in this context does not imply that the LAPB module is a +separately loadable module, although it may be. The term module is used in +its more standard meaning. + +The interface to the LAPB module consists of functions to the module, +callbacks from the module to indicate important state changes, and +structures for getting and setting information about the module. + +Structures +---------- + +Probably the most important structure is the skbuff structure for holding +received and transmitted data, however it is beyond the scope of this +document. + +The two LAPB specific structures are the LAPB initialisation structure and +the LAPB parameter structure. These will be defined in a standard header +file, <linux/lapb.h>. The header file <net/lapb.h> is internal to the LAPB +module and is not for use. + +LAPB Initialisation Structure +----------------------------- + +This structure is used only once, in the call to lapb_register (see below). +It contains information about the device driver that requires the services +of the LAPB module:: + + struct lapb_register_struct { + void (*connect_confirmation)(int token, int reason); + void (*connect_indication)(int token, int reason); + void (*disconnect_confirmation)(int token, int reason); + void (*disconnect_indication)(int token, int reason); + int (*data_indication)(int token, struct sk_buff *skb); + void (*data_transmit)(int token, struct sk_buff *skb); + }; + +Each member of this structure corresponds to a function in the device driver +that is called when a particular event in the LAPB module occurs. These will +be described in detail below. If a callback is not required (!!) then a NULL +may be substituted. + + +LAPB Parameter Structure +------------------------ + +This structure is used with the lapb_getparms and lapb_setparms functions +(see below). They are used to allow the device driver to get and set the +operational parameters of the LAPB implementation for a given connection:: + + struct lapb_parms_struct { + unsigned int t1; + unsigned int t1timer; + unsigned int t2; + unsigned int t2timer; + unsigned int n2; + unsigned int n2count; + unsigned int window; + unsigned int state; + unsigned int mode; + }; + +T1 and T2 are protocol timing parameters and are given in units of 100ms. N2 +is the maximum number of tries on the link before it is declared a failure. +The window size is the maximum number of outstanding data packets allowed to +be unacknowledged by the remote end, the value of the window is between 1 +and 7 for a standard LAPB link, and between 1 and 127 for an extended LAPB +link. + +The mode variable is a bit field used for setting (at present) three values. +The bit fields have the following meanings: + +====== ================================================= +Bit Meaning +====== ================================================= +0 LAPB operation (0=LAPB_STANDARD 1=LAPB_EXTENDED). +1 [SM]LP operation (0=LAPB_SLP 1=LAPB=MLP). +2 DTE/DCE operation (0=LAPB_DTE 1=LAPB_DCE) +3-31 Reserved, must be 0. +====== ================================================= + +Extended LAPB operation indicates the use of extended sequence numbers and +consequently larger window sizes, the default is standard LAPB operation. +MLP operation is the same as SLP operation except that the addresses used by +LAPB are different to indicate the mode of operation, the default is Single +Link Procedure. The difference between DCE and DTE operation is (i) the +addresses used for commands and responses, and (ii) when the DCE is not +connected, it sends DM without polls set, every T1. The upper case constant +names will be defined in the public LAPB header file. + + +Functions +--------- + +The LAPB module provides a number of function entry points. + +:: + + int lapb_register(void *token, struct lapb_register_struct); + +This must be called before the LAPB module may be used. If the call is +successful then LAPB_OK is returned. The token must be a unique identifier +generated by the device driver to allow for the unique identification of the +instance of the LAPB link. It is returned by the LAPB module in all of the +callbacks, and is used by the device driver in all calls to the LAPB module. +For multiple LAPB links in a single device driver, multiple calls to +lapb_register must be made. The format of the lapb_register_struct is given +above. The return values are: + +============= ============================= +LAPB_OK LAPB registered successfully. +LAPB_BADTOKEN Token is already registered. +LAPB_NOMEM Out of memory +============= ============================= + +:: + + int lapb_unregister(void *token); + +This releases all the resources associated with a LAPB link. Any current +LAPB link will be abandoned without further messages being passed. After +this call, the value of token is no longer valid for any calls to the LAPB +function. The valid return values are: + +============= =============================== +LAPB_OK LAPB unregistered successfully. +LAPB_BADTOKEN Invalid/unknown LAPB token. +============= =============================== + +:: + + int lapb_getparms(void *token, struct lapb_parms_struct *parms); + +This allows the device driver to get the values of the current LAPB +variables, the lapb_parms_struct is described above. The valid return values +are: + +============= ============================= +LAPB_OK LAPB getparms was successful. +LAPB_BADTOKEN Invalid/unknown LAPB token. +============= ============================= + +:: + + int lapb_setparms(void *token, struct lapb_parms_struct *parms); + +This allows the device driver to set the values of the current LAPB +variables, the lapb_parms_struct is described above. The values of t1timer, +t2timer and n2count are ignored, likewise changing the mode bits when +connected will be ignored. An error implies that none of the values have +been changed. The valid return values are: + +============= ================================================= +LAPB_OK LAPB getparms was successful. +LAPB_BADTOKEN Invalid/unknown LAPB token. +LAPB_INVALUE One of the values was out of its allowable range. +============= ================================================= + +:: + + int lapb_connect_request(void *token); + +Initiate a connect using the current parameter settings. The valid return +values are: + +============== ================================= +LAPB_OK LAPB is starting to connect. +LAPB_BADTOKEN Invalid/unknown LAPB token. +LAPB_CONNECTED LAPB module is already connected. +============== ================================= + +:: + + int lapb_disconnect_request(void *token); + +Initiate a disconnect. The valid return values are: + +================= =============================== +LAPB_OK LAPB is starting to disconnect. +LAPB_BADTOKEN Invalid/unknown LAPB token. +LAPB_NOTCONNECTED LAPB module is not connected. +================= =============================== + +:: + + int lapb_data_request(void *token, struct sk_buff *skb); + +Queue data with the LAPB module for transmitting over the link. If the call +is successful then the skbuff is owned by the LAPB module and may not be +used by the device driver again. The valid return values are: + +================= ============================= +LAPB_OK LAPB has accepted the data. +LAPB_BADTOKEN Invalid/unknown LAPB token. +LAPB_NOTCONNECTED LAPB module is not connected. +================= ============================= + +:: + + int lapb_data_received(void *token, struct sk_buff *skb); + +Queue data with the LAPB module which has been received from the device. It +is expected that the data passed to the LAPB module has skb->data pointing +to the beginning of the LAPB data. If the call is successful then the skbuff +is owned by the LAPB module and may not be used by the device driver again. +The valid return values are: + +============= =========================== +LAPB_OK LAPB has accepted the data. +LAPB_BADTOKEN Invalid/unknown LAPB token. +============= =========================== + +Callbacks +--------- + +These callbacks are functions provided by the device driver for the LAPB +module to call when an event occurs. They are registered with the LAPB +module with lapb_register (see above) in the structure lapb_register_struct +(see above). + +:: + + void (*connect_confirmation)(void *token, int reason); + +This is called by the LAPB module when a connection is established after +being requested by a call to lapb_connect_request (see above). The reason is +always LAPB_OK. + +:: + + void (*connect_indication)(void *token, int reason); + +This is called by the LAPB module when the link is established by the remote +system. The value of reason is always LAPB_OK. + +:: + + void (*disconnect_confirmation)(void *token, int reason); + +This is called by the LAPB module when an event occurs after the device +driver has called lapb_disconnect_request (see above). The reason indicates +what has happened. In all cases the LAPB link can be regarded as being +terminated. The values for reason are: + +================= ==================================================== +LAPB_OK The LAPB link was terminated normally. +LAPB_NOTCONNECTED The remote system was not connected. +LAPB_TIMEDOUT No response was received in N2 tries from the remote + system. +================= ==================================================== + +:: + + void (*disconnect_indication)(void *token, int reason); + +This is called by the LAPB module when the link is terminated by the remote +system or another event has occurred to terminate the link. This may be +returned in response to a lapb_connect_request (see above) if the remote +system refused the request. The values for reason are: + +================= ==================================================== +LAPB_OK The LAPB link was terminated normally by the remote + system. +LAPB_REFUSED The remote system refused the connect request. +LAPB_NOTCONNECTED The remote system was not connected. +LAPB_TIMEDOUT No response was received in N2 tries from the remote + system. +================= ==================================================== + +:: + + int (*data_indication)(void *token, struct sk_buff *skb); + +This is called by the LAPB module when data has been received from the +remote system that should be passed onto the next layer in the protocol +stack. The skbuff becomes the property of the device driver and the LAPB +module will not perform any more actions on it. The skb->data pointer will +be pointing to the first byte of data after the LAPB header. + +This method should return NET_RX_DROP (as defined in the header +file include/linux/netdevice.h) if and only if the frame was dropped +before it could be delivered to the upper layer. + +:: + + void (*data_transmit)(void *token, struct sk_buff *skb); + +This is called by the LAPB module when data is to be transmitted to the +remote system by the device driver. The skbuff becomes the property of the +device driver and the LAPB module will not perform any more actions on it. +The skb->data pointer will be pointing to the first byte of the LAPB header. diff --git a/Documentation/networking/mac80211-auth-assoc-deauth.txt b/Documentation/networking/mac80211-auth-assoc-deauth.txt new file mode 100644 index 0000000000..d7a15fe91b --- /dev/null +++ b/Documentation/networking/mac80211-auth-assoc-deauth.txt @@ -0,0 +1,95 @@ +# +# This outlines the Linux authentication/association and +# deauthentication/disassociation flows. +# +# This can be converted into a diagram using the service +# at http://www.websequencediagrams.com/ +# + +participant userspace +participant mac80211 +participant driver + +alt authentication needed (not FT) +userspace->mac80211: authenticate + +alt authenticated/authenticating already +mac80211->driver: sta_state(AP, not-exists) +mac80211->driver: bss_info_changed(clear BSSID) +else associated +note over mac80211,driver +like deauth/disassoc, without sending the +BA session stop & deauth/disassoc frames +end note +end + +mac80211->driver: config(channel, channel type) +mac80211->driver: bss_info_changed(set BSSID, basic rate bitmap) +mac80211->driver: sta_state(AP, exists) + +alt no probe request data known +mac80211->driver: TX directed probe request +driver->mac80211: RX probe response +end + +mac80211->driver: TX auth frame +driver->mac80211: RX auth frame + +alt WEP shared key auth +mac80211->driver: TX auth frame +driver->mac80211: RX auth frame +end + +mac80211->driver: sta_state(AP, authenticated) +mac80211->userspace: RX auth frame + +end + +userspace->mac80211: associate +alt authenticated or associated +note over mac80211,driver: cleanup like for authenticate +end + +alt not previously authenticated (FT) +mac80211->driver: config(channel, channel type) +mac80211->driver: bss_info_changed(set BSSID, basic rate bitmap) +mac80211->driver: sta_state(AP, exists) +mac80211->driver: sta_state(AP, authenticated) +end +mac80211->driver: TX assoc +driver->mac80211: RX assoc response +note over mac80211: init rate control +mac80211->driver: sta_state(AP, associated) + +alt not using WPA +mac80211->driver: sta_state(AP, authorized) +end + +mac80211->driver: set up QoS parameters + +mac80211->driver: bss_info_changed(QoS, HT, associated with AID) +mac80211->userspace: associated + +note left of userspace: associated now + +alt using WPA +note over userspace +do 4-way-handshake +(data frames) +end note +userspace->mac80211: authorized +mac80211->driver: sta_state(AP, authorized) +end + +userspace->mac80211: deauthenticate/disassociate +mac80211->driver: stop BA sessions +mac80211->driver: TX deauth/disassoc +mac80211->driver: flush frames +mac80211->driver: sta_state(AP,associated) +mac80211->driver: sta_state(AP,authenticated) +mac80211->driver: sta_state(AP,exists) +mac80211->driver: sta_state(AP,not-exists) +mac80211->driver: turn off powersave +mac80211->driver: bss_info_changed(clear BSSID, not associated, no QoS, ...) +mac80211->driver: config(channel type to non-HT) +mac80211->userspace: disconnected diff --git a/Documentation/networking/mac80211-injection.rst b/Documentation/networking/mac80211-injection.rst new file mode 100644 index 0000000000..63ba6611fd --- /dev/null +++ b/Documentation/networking/mac80211-injection.rst @@ -0,0 +1,106 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================================= +How to use packet injection with mac80211 +========================================= + +mac80211 now allows arbitrary packets to be injected down any Monitor Mode +interface from userland. The packet you inject needs to be composed in the +following format:: + + [ radiotap header ] + [ ieee80211 header ] + [ payload ] + +The radiotap format is discussed in +./Documentation/networking/radiotap-headers.rst. + +Despite many radiotap parameters being currently defined, most only make sense +to appear on received packets. The following information is parsed from the +radiotap headers and used to control injection: + + * IEEE80211_RADIOTAP_FLAGS + + ========================= =========================================== + IEEE80211_RADIOTAP_F_FCS FCS will be removed and recalculated + IEEE80211_RADIOTAP_F_WEP frame will be encrypted if key available + IEEE80211_RADIOTAP_F_FRAG frame will be fragmented if longer than the + current fragmentation threshold. + ========================= =========================================== + + * IEEE80211_RADIOTAP_TX_FLAGS + + ============================= ======================================== + IEEE80211_RADIOTAP_F_TX_NOACK frame should be sent without waiting for + an ACK even if it is a unicast frame + ============================= ======================================== + + * IEEE80211_RADIOTAP_RATE + + legacy rate for the transmission (only for devices without own rate control) + + * IEEE80211_RADIOTAP_MCS + + HT rate for the transmission (only for devices without own rate control). + Also some flags are parsed + + ============================ ======================== + IEEE80211_RADIOTAP_MCS_SGI use short guard interval + IEEE80211_RADIOTAP_MCS_BW_40 send in HT40 mode + ============================ ======================== + + * IEEE80211_RADIOTAP_DATA_RETRIES + + number of retries when either IEEE80211_RADIOTAP_RATE or + IEEE80211_RADIOTAP_MCS was used + + * IEEE80211_RADIOTAP_VHT + + VHT mcs and number of streams used in the transmission (only for devices + without own rate control). Also other fields are parsed + + flags field + IEEE80211_RADIOTAP_VHT_FLAG_SGI: use short guard interval + + bandwidth field + * 1: send using 40MHz channel width + * 4: send using 80MHz channel width + * 11: send using 160MHz channel width + +The injection code can also skip all other currently defined radiotap fields +facilitating replay of captured radiotap headers directly. + +Here is an example valid radiotap header defining some parameters:: + + 0x00, 0x00, // <-- radiotap version + 0x0b, 0x00, // <- radiotap header length + 0x04, 0x0c, 0x00, 0x00, // <-- bitmap + 0x6c, // <-- rate + 0x0c, //<-- tx power + 0x01 //<-- antenna + +The ieee80211 header follows immediately afterwards, looking for example like +this:: + + 0x08, 0x01, 0x00, 0x00, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0x13, 0x22, 0x33, 0x44, 0x55, 0x66, + 0x13, 0x22, 0x33, 0x44, 0x55, 0x66, + 0x10, 0x86 + +Then lastly there is the payload. + +After composing the packet contents, it is sent by send()-ing it to a logical +mac80211 interface that is in Monitor mode. Libpcap can also be used, +(which is easier than doing the work to bind the socket to the right +interface), along the following lines::: + + ppcap = pcap_open_live(szInterfaceName, 800, 1, 20, szErrbuf); + ... + r = pcap_inject(ppcap, u8aSendBuffer, nLength); + +You can also find a link to a complete inject application here: + +https://wireless.wiki.kernel.org/en/users/Documentation/packetspammer + +Andy Green <andy@warmcat.com> diff --git a/Documentation/networking/mac80211_hwsim/hostapd.conf b/Documentation/networking/mac80211_hwsim/hostapd.conf new file mode 100644 index 0000000000..08cde7e35f --- /dev/null +++ b/Documentation/networking/mac80211_hwsim/hostapd.conf @@ -0,0 +1,11 @@ +interface=wlan0 +driver=nl80211 + +hw_mode=g +channel=1 +ssid=mac80211 test + +wpa=2 +wpa_key_mgmt=WPA-PSK +wpa_pairwise=CCMP +wpa_passphrase=12345678 diff --git a/Documentation/networking/mac80211_hwsim/mac80211_hwsim.rst b/Documentation/networking/mac80211_hwsim/mac80211_hwsim.rst new file mode 100644 index 0000000000..d2266ce553 --- /dev/null +++ b/Documentation/networking/mac80211_hwsim/mac80211_hwsim.rst @@ -0,0 +1,80 @@ +:orphan: + +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> + +=================================================================== +mac80211_hwsim - software simulator of 802.11 radio(s) for mac80211 +=================================================================== + +:Copyright: |copy| 2008, Jouni Malinen <j@w1.fi> + +This program is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License version 2 as +published by the Free Software Foundation. + + +Introduction +============ + +mac80211_hwsim is a Linux kernel module that can be used to simulate +arbitrary number of IEEE 802.11 radios for mac80211. It can be used to +test most of the mac80211 functionality and user space tools (e.g., +hostapd and wpa_supplicant) in a way that matches very closely with +the normal case of using real WLAN hardware. From the mac80211 view +point, mac80211_hwsim is yet another hardware driver, i.e., no changes +to mac80211 are needed to use this testing tool. + +The main goal for mac80211_hwsim is to make it easier for developers +to test their code and work with new features to mac80211, hostapd, +and wpa_supplicant. The simulated radios do not have the limitations +of real hardware, so it is easy to generate an arbitrary test setup +and always reproduce the same setup for future tests. In addition, +since all radio operation is simulated, any channel can be used in +tests regardless of regulatory rules. + +mac80211_hwsim kernel module has a parameter 'radios' that can be used +to select how many radios are simulated (default 2). This allows +configuration of both very simply setups (e.g., just a single access +point and a station) or large scale tests (multiple access points with +hundreds of stations). + +mac80211_hwsim works by tracking the current channel of each virtual +radio and copying all transmitted frames to all other radios that are +currently enabled and on the same channel as the transmitting +radio. Software encryption in mac80211 is used so that the frames are +actually encrypted over the virtual air interface to allow more +complete testing of encryption. + +A global monitoring netdev, hwsim#, is created independent of +mac80211. This interface can be used to monitor all transmitted frames +regardless of channel. + + +Simple example +============== + +This example shows how to use mac80211_hwsim to simulate two radios: +one to act as an access point and the other as a station that +associates with the AP. hostapd and wpa_supplicant are used to take +care of WPA2-PSK authentication. In addition, hostapd is also +processing access point side of association. + +:: + + + # Build mac80211_hwsim as part of kernel configuration + + # Load the module + modprobe mac80211_hwsim + + # Run hostapd (AP) for wlan0 + hostapd hostapd.conf + + # Run wpa_supplicant (station) for wlan1 + wpa_supplicant -Dnl80211 -iwlan1 -c wpa_supplicant.conf + + +More test cases are available in hostap.git: +git://w1.fi/srv/git/hostap.git and mac80211_hwsim/tests subdirectory +(http://w1.fi/gitweb/gitweb.cgi?p=hostap.git;a=tree;f=mac80211_hwsim/tests) diff --git a/Documentation/networking/mac80211_hwsim/wpa_supplicant.conf b/Documentation/networking/mac80211_hwsim/wpa_supplicant.conf new file mode 100644 index 0000000000..299128cff0 --- /dev/null +++ b/Documentation/networking/mac80211_hwsim/wpa_supplicant.conf @@ -0,0 +1,10 @@ +ctrl_interface=/var/run/wpa_supplicant + +network={ + ssid="mac80211 test" + psk="12345678" + key_mgmt=WPA-PSK + proto=WPA2 + pairwise=CCMP + group=CCMP +} diff --git a/Documentation/networking/mctp.rst b/Documentation/networking/mctp.rst new file mode 100644 index 0000000000..c628cb5406 --- /dev/null +++ b/Documentation/networking/mctp.rst @@ -0,0 +1,320 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================================== +Management Component Transport Protocol (MCTP) +============================================== + +net/mctp/ contains protocol support for MCTP, as defined by DMTF standard +DSP0236. Physical interface drivers ("bindings" in the specification) are +provided in drivers/net/mctp/. + +The core code provides a socket-based interface to send and receive MCTP +messages, through an AF_MCTP, SOCK_DGRAM socket. + +Structure: interfaces & networks +================================ + +The kernel models the local MCTP topology through two items: interfaces and +networks. + +An interface (or "link") is an instance of an MCTP physical transport binding +(as defined by DSP0236, section 3.2.47), likely connected to a specific hardware +device. This is represented as a ``struct netdevice``. + +A network defines a unique address space for MCTP endpoints by endpoint-ID +(described by DSP0236, section 3.2.31). A network has a user-visible identifier +to allow references from userspace. Route definitions are specific to one +network. + +Interfaces are associated with one network. A network may be associated with one +or more interfaces. + +If multiple networks are present, each may contain endpoint IDs (EIDs) that are +also present on other networks. + +Sockets API +=========== + +Protocol definitions +-------------------- + +MCTP uses ``AF_MCTP`` / ``PF_MCTP`` for the address- and protocol- families. +Since MCTP is message-based, only ``SOCK_DGRAM`` sockets are supported. + +.. code-block:: C + + int sd = socket(AF_MCTP, SOCK_DGRAM, 0); + +The only (current) value for the ``protocol`` argument is 0. + +As with all socket address families, source and destination addresses are +specified with a ``sockaddr`` type, with a single-byte endpoint address: + +.. code-block:: C + + typedef __u8 mctp_eid_t; + + struct mctp_addr { + mctp_eid_t s_addr; + }; + + struct sockaddr_mctp { + __kernel_sa_family_t smctp_family; + unsigned int smctp_network; + struct mctp_addr smctp_addr; + __u8 smctp_type; + __u8 smctp_tag; + }; + + #define MCTP_NET_ANY 0x0 + #define MCTP_ADDR_ANY 0xff + + +Syscall behaviour +----------------- + +The following sections describe the MCTP-specific behaviours of the standard +socket system calls. These behaviours have been chosen to map closely to the +existing sockets APIs. + +``bind()`` : set local socket address +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Sockets that receive incoming request packets will bind to a local address, +using the ``bind()`` syscall. + +.. code-block:: C + + struct sockaddr_mctp addr; + + addr.smctp_family = AF_MCTP; + addr.smctp_network = MCTP_NET_ANY; + addr.smctp_addr.s_addr = MCTP_ADDR_ANY; + addr.smctp_type = MCTP_TYPE_PLDM; + addr.smctp_tag = MCTP_TAG_OWNER; + + int rc = bind(sd, (struct sockaddr *)&addr, sizeof(addr)); + +This establishes the local address of the socket. Incoming MCTP messages that +match the network, address, and message type will be received by this socket. +The reference to 'incoming' is important here; a bound socket will only receive +messages with the TO bit set, to indicate an incoming request message, rather +than a response. + +The ``smctp_tag`` value will configure the tags accepted from the remote side of +this socket. Given the above, the only valid value is ``MCTP_TAG_OWNER``, which +will result in remotely "owned" tags being routed to this socket. Since +``MCTP_TAG_OWNER`` is set, the 3 least-significant bits of ``smctp_tag`` are not +used; callers must set them to zero. + +A ``smctp_network`` value of ``MCTP_NET_ANY`` will configure the socket to +receive incoming packets from any locally-connected network. A specific network +value will cause the socket to only receive incoming messages from that network. + +The ``smctp_addr`` field specifies a local address to bind to. A value of +``MCTP_ADDR_ANY`` configures the socket to receive messages addressed to any +local destination EID. + +The ``smctp_type`` field specifies which message types to receive. Only the +lower 7 bits of the type is matched on incoming messages (ie., the +most-significant IC bit is not part of the match). This results in the socket +receiving packets with and without a message integrity check footer. + +``sendto()``, ``sendmsg()``, ``send()`` : transmit an MCTP message +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +An MCTP message is transmitted using one of the ``sendto()``, ``sendmsg()`` or +``send()`` syscalls. Using ``sendto()`` as the primary example: + +.. code-block:: C + + struct sockaddr_mctp addr; + char buf[14]; + ssize_t len; + + /* set message destination */ + addr.smctp_family = AF_MCTP; + addr.smctp_network = 0; + addr.smctp_addr.s_addr = 8; + addr.smctp_tag = MCTP_TAG_OWNER; + addr.smctp_type = MCTP_TYPE_ECHO; + + /* arbitrary message to send, with message-type header */ + buf[0] = MCTP_TYPE_ECHO; + memcpy(buf + 1, "hello, world!", sizeof(buf) - 1); + + len = sendto(sd, buf, sizeof(buf), 0, + (struct sockaddr_mctp *)&addr, sizeof(addr)); + +The network and address fields of ``addr`` define the remote address to send to. +If ``smctp_tag`` has the ``MCTP_TAG_OWNER``, the kernel will ignore any bits set +in ``MCTP_TAG_VALUE``, and generate a tag value suitable for the destination +EID. If ``MCTP_TAG_OWNER`` is not set, the message will be sent with the tag +value as specified. If a tag value cannot be allocated, the system call will +report an errno of ``EAGAIN``. + +The application must provide the message type byte as the first byte of the +message buffer passed to ``sendto()``. If a message integrity check is to be +included in the transmitted message, it must also be provided in the message +buffer, and the most-significant bit of the message type byte must be 1. + +The ``sendmsg()`` system call allows a more compact argument interface, and the +message buffer to be specified as a scatter-gather list. At present no ancillary +message types (used for the ``msg_control`` data passed to ``sendmsg()``) are +defined. + +Transmitting a message on an unconnected socket with ``MCTP_TAG_OWNER`` +specified will cause an allocation of a tag, if no valid tag is already +allocated for that destination. The (destination-eid,tag) tuple acts as an +implicit local socket address, to allow the socket to receive responses to this +outgoing message. If any previous allocation has been performed (to for a +different remote EID), that allocation is lost. + +Sockets will only receive responses to requests they have sent (with TO=1) and +may only respond (with TO=0) to requests they have received. + +``recvfrom()``, ``recvmsg()``, ``recv()`` : receive an MCTP message +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +An MCTP message can be received by an application using one of the +``recvfrom()``, ``recvmsg()``, or ``recv()`` system calls. Using ``recvfrom()`` +as the primary example: + +.. code-block:: C + + struct sockaddr_mctp addr; + socklen_t addrlen; + char buf[14]; + ssize_t len; + + addrlen = sizeof(addr); + + len = recvfrom(sd, buf, sizeof(buf), 0, + (struct sockaddr_mctp *)&addr, &addrlen); + + /* We can expect addr to describe an MCTP address */ + assert(addrlen >= sizeof(buf)); + assert(addr.smctp_family == AF_MCTP); + + printf("received %zd bytes from remote EID %d\n", rc, addr.smctp_addr); + +The address argument to ``recvfrom`` and ``recvmsg`` is populated with the +remote address of the incoming message, including tag value (this will be needed +in order to reply to the message). + +The first byte of the message buffer will contain the message type byte. If an +integrity check follows the message, it will be included in the received buffer. + +The ``recv()`` system call behaves in a similar way, but does not provide a +remote address to the application. Therefore, these are only useful if the +remote address is already known, or the message does not require a reply. + +Like the send calls, sockets will only receive responses to requests they have +sent (TO=1) and may only respond (TO=0) to requests they have received. + +``ioctl(SIOCMCTPALLOCTAG)`` and ``ioctl(SIOCMCTPDROPTAG)`` +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +These tags give applications more control over MCTP message tags, by allocating +(and dropping) tag values explicitly, rather than the kernel automatically +allocating a per-message tag at ``sendmsg()`` time. + +In general, you will only need to use these ioctls if your MCTP protocol does +not fit the usual request/response model. For example, if you need to persist +tags across multiple requests, or a request may generate more than one response. +In these cases, the ioctls allow you to decouple the tag allocation (and +release) from individual message send and receive operations. + +Both ioctls are passed a pointer to a ``struct mctp_ioc_tag_ctl``: + +.. code-block:: C + + struct mctp_ioc_tag_ctl { + mctp_eid_t peer_addr; + __u8 tag; + __u16 flags; + }; + +``SIOCMCTPALLOCTAG`` allocates a tag for a specific peer, which an application +can use in future ``sendmsg()`` calls. The application populates the +``peer_addr`` member with the remote EID. Other fields must be zero. + +On return, the ``tag`` member will be populated with the allocated tag value. +The allocated tag will have the following tag bits set: + + - ``MCTP_TAG_OWNER``: it only makes sense to allocate tags if you're the tag + owner + + - ``MCTP_TAG_PREALLOC``: to indicate to ``sendmsg()`` that this is a + preallocated tag. + + - ... and the actual tag value, within the least-significant three bits + (``MCTP_TAG_MASK``). Note that zero is a valid tag value. + +The tag value should be used as-is for the ``smctp_tag`` member of ``struct +sockaddr_mctp``. + +``SIOCMCTPDROPTAG`` releases a tag that has been previously allocated by a +``SIOCMCTPALLOCTAG`` ioctl. The ``peer_addr`` must be the same as used for the +allocation, and the ``tag`` value must match exactly the tag returned from the +allocation (including the ``MCTP_TAG_OWNER`` and ``MCTP_TAG_PREALLOC`` bits). +The ``flags`` field must be zero. + +Kernel internals +================ + +There are a few possible packet flows in the MCTP stack: + +1. local TX to remote endpoint, message <= MTU:: + + sendmsg() + -> mctp_local_output() + : route lookup + -> rt->output() (== mctp_route_output) + -> dev_queue_xmit() + +2. local TX to remote endpoint, message > MTU:: + + sendmsg() + -> mctp_local_output() + -> mctp_do_fragment_route() + : creates packet-sized skbs. For each new skb: + -> rt->output() (== mctp_route_output) + -> dev_queue_xmit() + +3. remote TX to local endpoint, single-packet message:: + + mctp_pkttype_receive() + : route lookup + -> rt->output() (== mctp_route_input) + : sk_key lookup + -> sock_queue_rcv_skb() + +4. remote TX to local endpoint, multiple-packet message:: + + mctp_pkttype_receive() + : route lookup + -> rt->output() (== mctp_route_input) + : sk_key lookup + : stores skb in struct sk_key->reasm_head + + mctp_pkttype_receive() + : route lookup + -> rt->output() (== mctp_route_input) + : sk_key lookup + : finds existing reassembly in sk_key->reasm_head + : appends new fragment + -> sock_queue_rcv_skb() + +Key refcounts +------------- + + * keys are refed by: + + - a skb: during route output, stored in ``skb->cb``. + + - netns and sock lists. + + * keys can be associated with a device, in which case they hold a + reference to the dev (set through ``key->dev``, counted through + ``dev->key_count``). Multiple keys can reference the device. diff --git a/Documentation/networking/mpls-sysctl.rst b/Documentation/networking/mpls-sysctl.rst new file mode 100644 index 0000000000..0a2ac88404 --- /dev/null +++ b/Documentation/networking/mpls-sysctl.rst @@ -0,0 +1,57 @@ +.. SPDX-License-Identifier: GPL-2.0 + +==================== +MPLS Sysfs variables +==================== + +/proc/sys/net/mpls/* Variables: +=============================== + +platform_labels - INTEGER + Number of entries in the platform label table. It is not + possible to configure forwarding for label values equal to or + greater than the number of platform labels. + + A dense utilization of the entries in the platform label table + is possible and expected as the platform labels are locally + allocated. + + If the number of platform label table entries is set to 0 no + label will be recognized by the kernel and mpls forwarding + will be disabled. + + Reducing this value will remove all label routing entries that + no longer fit in the table. + + Possible values: 0 - 1048575 + + Default: 0 + +ip_ttl_propagate - BOOL + Control whether TTL is propagated from the IPv4/IPv6 header to + the MPLS header on imposing labels and propagated from the + MPLS header to the IPv4/IPv6 header on popping the last label. + + If disabled, the MPLS transport network will appear as a + single hop to transit traffic. + + * 0 - disabled / RFC 3443 [Short] Pipe Model + * 1 - enabled / RFC 3443 Uniform Model (default) + +default_ttl - INTEGER + Default TTL value to use for MPLS packets where it cannot be + propagated from an IP header, either because one isn't present + or ip_ttl_propagate has been disabled. + + Possible values: 1 - 255 + + Default: 255 + +conf/<interface>/input - BOOL + Control whether packets can be input on this interface. + + If disabled, packets will be discarded without further + processing. + + * 0 - disabled (default) + * not 0 - enabled diff --git a/Documentation/networking/mptcp-sysctl.rst b/Documentation/networking/mptcp-sysctl.rst new file mode 100644 index 0000000000..15f1919d64 --- /dev/null +++ b/Documentation/networking/mptcp-sysctl.rst @@ -0,0 +1,84 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================== +MPTCP Sysfs variables +===================== + +/proc/sys/net/mptcp/* Variables +=============================== + +enabled - BOOLEAN + Control whether MPTCP sockets can be created. + + MPTCP sockets can be created if the value is 1. This is a + per-namespace sysctl. + + Default: 1 (enabled) + +add_addr_timeout - INTEGER (seconds) + Set the timeout after which an ADD_ADDR control message will be + resent to an MPTCP peer that has not acknowledged a previous + ADD_ADDR message. + + The default value matches TCP_RTO_MAX. This is a per-namespace + sysctl. + + Default: 120 + +checksum_enabled - BOOLEAN + Control whether DSS checksum can be enabled. + + DSS checksum can be enabled if the value is nonzero. This is a + per-namespace sysctl. + + Default: 0 + +allow_join_initial_addr_port - BOOLEAN + Allow peers to send join requests to the IP address and port number used + by the initial subflow if the value is 1. This controls a flag that is + sent to the peer at connection time, and whether such join requests are + accepted or denied. + + Joins to addresses advertised with ADD_ADDR are not affected by this + value. + + This is a per-namespace sysctl. + + Default: 1 + +pm_type - INTEGER + Set the default path manager type to use for each new MPTCP + socket. In-kernel path management will control subflow + connections and address advertisements according to + per-namespace values configured over the MPTCP netlink + API. Userspace path management puts per-MPTCP-connection subflow + connection decisions and address advertisements under control of + a privileged userspace program, at the cost of more netlink + traffic to propagate all of the related events and commands. + + This is a per-namespace sysctl. + + * 0 - In-kernel path manager + * 1 - Userspace path manager + + Default: 0 + +stale_loss_cnt - INTEGER + The number of MPTCP-level retransmission intervals with no traffic and + pending outstanding data on a given subflow required to declare it stale. + The packet scheduler ignores stale subflows. + A low stale_loss_cnt value allows for fast active-backup switch-over, + an high value maximize links utilization on edge scenarios e.g. lossy + link with high BER or peer pausing the data processing. + + This is a per-namespace sysctl. + + Default: 4 + +scheduler - STRING + Select the scheduler of your choice. + + Support for selection of different schedulers. This is a per-namespace + sysctl. + + Default: "default" diff --git a/Documentation/networking/msg_zerocopy.rst b/Documentation/networking/msg_zerocopy.rst new file mode 100644 index 0000000000..b3ea96af9b --- /dev/null +++ b/Documentation/networking/msg_zerocopy.rst @@ -0,0 +1,256 @@ + +============ +MSG_ZEROCOPY +============ + +Intro +===== + +The MSG_ZEROCOPY flag enables copy avoidance for socket send calls. +The feature is currently implemented for TCP and UDP sockets. + + +Opportunity and Caveats +----------------------- + +Copying large buffers between user process and kernel can be +expensive. Linux supports various interfaces that eschew copying, +such as sendfile and splice. The MSG_ZEROCOPY flag extends the +underlying copy avoidance mechanism to common socket send calls. + +Copy avoidance is not a free lunch. As implemented, with page pinning, +it replaces per byte copy cost with page accounting and completion +notification overhead. As a result, MSG_ZEROCOPY is generally only +effective at writes over around 10 KB. + +Page pinning also changes system call semantics. It temporarily shares +the buffer between process and network stack. Unlike with copying, the +process cannot immediately overwrite the buffer after system call +return without possibly modifying the data in flight. Kernel integrity +is not affected, but a buggy program can possibly corrupt its own data +stream. + +The kernel returns a notification when it is safe to modify data. +Converting an existing application to MSG_ZEROCOPY is not always as +trivial as just passing the flag, then. + + +More Info +--------- + +Much of this document was derived from a longer paper presented at +netdev 2.1. For more in-depth information see that paper and talk, +the excellent reporting over at LWN.net or read the original code. + + paper, slides, video + https://netdevconf.org/2.1/session.html?debruijn + + LWN article + https://lwn.net/Articles/726917/ + + patchset + [PATCH net-next v4 0/9] socket sendmsg MSG_ZEROCOPY + https://lore.kernel.org/netdev/20170803202945.70750-1-willemdebruijn.kernel@gmail.com + + +Interface +========= + +Passing the MSG_ZEROCOPY flag is the most obvious step to enable copy +avoidance, but not the only one. + +Socket Setup +------------ + +The kernel is permissive when applications pass undefined flags to the +send system call. By default it simply ignores these. To avoid enabling +copy avoidance mode for legacy processes that accidentally already pass +this flag, a process must first signal intent by setting a socket option: + +:: + + if (setsockopt(fd, SOL_SOCKET, SO_ZEROCOPY, &one, sizeof(one))) + error(1, errno, "setsockopt zerocopy"); + +Transmission +------------ + +The change to send (or sendto, sendmsg, sendmmsg) itself is trivial. +Pass the new flag. + +:: + + ret = send(fd, buf, sizeof(buf), MSG_ZEROCOPY); + +A zerocopy failure will return -1 with errno ENOBUFS. This happens if +the socket exceeds its optmem limit or the user exceeds their ulimit on +locked pages. + + +Mixing copy avoidance and copying +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Many workloads have a mixture of large and small buffers. Because copy +avoidance is more expensive than copying for small packets, the +feature is implemented as a flag. It is safe to mix calls with the flag +with those without. + + +Notifications +------------- + +The kernel has to notify the process when it is safe to reuse a +previously passed buffer. It queues completion notifications on the +socket error queue, akin to the transmit timestamping interface. + +The notification itself is a simple scalar value. Each socket +maintains an internal unsigned 32-bit counter. Each send call with +MSG_ZEROCOPY that successfully sends data increments the counter. The +counter is not incremented on failure or if called with length zero. +The counter counts system call invocations, not bytes. It wraps after +UINT_MAX calls. + + +Notification Reception +~~~~~~~~~~~~~~~~~~~~~~ + +The below snippet demonstrates the API. In the simplest case, each +send syscall is followed by a poll and recvmsg on the error queue. + +Reading from the error queue is always a non-blocking operation. The +poll call is there to block until an error is outstanding. It will set +POLLERR in its output flags. That flag does not have to be set in the +events field. Errors are signaled unconditionally. + +:: + + pfd.fd = fd; + pfd.events = 0; + if (poll(&pfd, 1, -1) != 1 || pfd.revents & POLLERR == 0) + error(1, errno, "poll"); + + ret = recvmsg(fd, &msg, MSG_ERRQUEUE); + if (ret == -1) + error(1, errno, "recvmsg"); + + read_notification(msg); + +The example is for demonstration purpose only. In practice, it is more +efficient to not wait for notifications, but read without blocking +every couple of send calls. + +Notifications can be processed out of order with other operations on +the socket. A socket that has an error queued would normally block +other operations until the error is read. Zerocopy notifications have +a zero error code, however, to not block send and recv calls. + + +Notification Batching +~~~~~~~~~~~~~~~~~~~~~ + +Multiple outstanding packets can be read at once using the recvmmsg +call. This is often not needed. In each message the kernel returns not +a single value, but a range. It coalesces consecutive notifications +while one is outstanding for reception on the error queue. + +When a new notification is about to be queued, it checks whether the +new value extends the range of the notification at the tail of the +queue. If so, it drops the new notification packet and instead increases +the range upper value of the outstanding notification. + +For protocols that acknowledge data in-order, like TCP, each +notification can be squashed into the previous one, so that no more +than one notification is outstanding at any one point. + +Ordered delivery is the common case, but not guaranteed. Notifications +may arrive out of order on retransmission and socket teardown. + + +Notification Parsing +~~~~~~~~~~~~~~~~~~~~ + +The below snippet demonstrates how to parse the control message: the +read_notification() call in the previous snippet. A notification +is encoded in the standard error format, sock_extended_err. + +The level and type fields in the control data are protocol family +specific, IP_RECVERR or IPV6_RECVERR. + +Error origin is the new type SO_EE_ORIGIN_ZEROCOPY. ee_errno is zero, +as explained before, to avoid blocking read and write system calls on +the socket. + +The 32-bit notification range is encoded as [ee_info, ee_data]. This +range is inclusive. Other fields in the struct must be treated as +undefined, bar for ee_code, as discussed below. + +:: + + struct sock_extended_err *serr; + struct cmsghdr *cm; + + cm = CMSG_FIRSTHDR(msg); + if (cm->cmsg_level != SOL_IP && + cm->cmsg_type != IP_RECVERR) + error(1, 0, "cmsg"); + + serr = (void *) CMSG_DATA(cm); + if (serr->ee_errno != 0 || + serr->ee_origin != SO_EE_ORIGIN_ZEROCOPY) + error(1, 0, "serr"); + + printf("completed: %u..%u\n", serr->ee_info, serr->ee_data); + + +Deferred copies +~~~~~~~~~~~~~~~ + +Passing flag MSG_ZEROCOPY is a hint to the kernel to apply copy +avoidance, and a contract that the kernel will queue a completion +notification. It is not a guarantee that the copy is elided. + +Copy avoidance is not always feasible. Devices that do not support +scatter-gather I/O cannot send packets made up of kernel generated +protocol headers plus zerocopy user data. A packet may need to be +converted to a private copy of data deep in the stack, say to compute +a checksum. + +In all these cases, the kernel returns a completion notification when +it releases its hold on the shared pages. That notification may arrive +before the (copied) data is fully transmitted. A zerocopy completion +notification is not a transmit completion notification, therefore. + +Deferred copies can be more expensive than a copy immediately in the +system call, if the data is no longer warm in the cache. The process +also incurs notification processing cost for no benefit. For this +reason, the kernel signals if data was completed with a copy, by +setting flag SO_EE_CODE_ZEROCOPY_COPIED in field ee_code on return. +A process may use this signal to stop passing flag MSG_ZEROCOPY on +subsequent requests on the same socket. + + +Implementation +============== + +Loopback +-------- + +Data sent to local sockets can be queued indefinitely if the receive +process does not read its socket. Unbound notification latency is not +acceptable. For this reason all packets generated with MSG_ZEROCOPY +that are looped to a local socket will incur a deferred copy. This +includes looping onto packet sockets (e.g., tcpdump) and tun devices. + + +Testing +======= + +More realistic example code can be found in the kernel source under +tools/testing/selftests/net/msg_zerocopy.c. + +Be cognizant of the loopback constraint. The test can be run between +a pair of hosts. But if run between a local pair of processes, for +instance when run with msg_zerocopy.sh between a veth pair across +namespaces, the test will not show any improvement. For testing, the +loopback restriction can be temporarily relaxed by making +skb_orphan_frags_rx identical to skb_orphan_frags. diff --git a/Documentation/networking/multiqueue.rst b/Documentation/networking/multiqueue.rst new file mode 100644 index 0000000000..0a576166e9 --- /dev/null +++ b/Documentation/networking/multiqueue.rst @@ -0,0 +1,78 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=========================================== +HOWTO for multiqueue network device support +=========================================== + +Section 1: Base driver requirements for implementing multiqueue support +======================================================================= + +Intro: Kernel support for multiqueue devices +--------------------------------------------------------- + +Kernel support for multiqueue devices is always present. + +Base drivers are required to use the new alloc_etherdev_mq() or +alloc_netdev_mq() functions to allocate the subqueues for the device. The +underlying kernel API will take care of the allocation and deallocation of +the subqueue memory, as well as netdev configuration of where the queues +exist in memory. + +The base driver will also need to manage the queues as it does the global +netdev->queue_lock today. Therefore base drivers should use the +netif_{start|stop|wake}_subqueue() functions to manage each queue while the +device is still operational. netdev->queue_lock is still used when the device +comes online or when it's completely shut down (unregister_netdev(), etc.). + + +Section 2: Qdisc support for multiqueue devices +=============================================== + +Currently two qdiscs are optimized for multiqueue devices. The first is the +default pfifo_fast qdisc. This qdisc supports one qdisc per hardware queue. +A new round-robin qdisc, sch_multiq also supports multiple hardware queues. The +qdisc is responsible for classifying the skb's and then directing the skb's to +bands and queues based on the value in skb->queue_mapping. Use this field in +the base driver to determine which queue to send the skb to. + +sch_multiq has been added for hardware that wishes to avoid head-of-line +blocking. It will cycle though the bands and verify that the hardware queue +associated with the band is not stopped prior to dequeuing a packet. + +On qdisc load, the number of bands is based on the number of queues on the +hardware. Once the association is made, any skb with skb->queue_mapping set, +will be queued to the band associated with the hardware queue. + + +Section 3: Brief howto using MULTIQ for multiqueue devices +========================================================== + +The userspace command 'tc,' part of the iproute2 package, is used to configure +qdiscs. To add the MULTIQ qdisc to your network device, assuming the device +is called eth0, run the following command:: + + # tc qdisc add dev eth0 root handle 1: multiq + +The qdisc will allocate the number of bands to equal the number of queues that +the device reports, and bring the qdisc online. Assuming eth0 has 4 Tx +queues, the band mapping would look like:: + + band 0 => queue 0 + band 1 => queue 1 + band 2 => queue 2 + band 3 => queue 3 + +Traffic will begin flowing through each queue based on either the simple_tx_hash +function or based on netdev->select_queue() if you have it defined. + +The behavior of tc filters remains the same. However a new tc action, +skbedit, has been added. Assuming you wanted to route all traffic to a +specific host, for example 192.168.0.3, through a specific queue you could use +this action and establish a filter such as:: + + tc filter add dev eth0 parent 1: protocol ip prio 1 u32 \ + match ip dst 192.168.0.3 \ + action skbedit queue_mapping 3 + +:Author: Alexander Duyck <alexander.h.duyck@intel.com> +:Original Author: Peter P. Waskiewicz Jr. <peter.p.waskiewicz.jr@intel.com> diff --git a/Documentation/networking/napi.rst b/Documentation/networking/napi.rst new file mode 100644 index 0000000000..7bf7b95c4f --- /dev/null +++ b/Documentation/networking/napi.rst @@ -0,0 +1,255 @@ +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) + +.. _napi: + +==== +NAPI +==== + +NAPI is the event handling mechanism used by the Linux networking stack. +The name NAPI no longer stands for anything in particular [#]_. + +In basic operation the device notifies the host about new events +via an interrupt. +The host then schedules a NAPI instance to process the events. +The device may also be polled for events via NAPI without receiving +interrupts first (:ref:`busy polling<poll>`). + +NAPI processing usually happens in the software interrupt context, +but there is an option to use :ref:`separate kernel threads<threaded>` +for NAPI processing. + +All in all NAPI abstracts away from the drivers the context and configuration +of event (packet Rx and Tx) processing. + +Driver API +========== + +The two most important elements of NAPI are the struct napi_struct +and the associated poll method. struct napi_struct holds the state +of the NAPI instance while the method is the driver-specific event +handler. The method will typically free Tx packets that have been +transmitted and process newly received packets. + +.. _drv_ctrl: + +Control API +----------- + +netif_napi_add() and netif_napi_del() add/remove a NAPI instance +from the system. The instances are attached to the netdevice passed +as argument (and will be deleted automatically when netdevice is +unregistered). Instances are added in a disabled state. + +napi_enable() and napi_disable() manage the disabled state. +A disabled NAPI can't be scheduled and its poll method is guaranteed +to not be invoked. napi_disable() waits for ownership of the NAPI +instance to be released. + +The control APIs are not idempotent. Control API calls are safe against +concurrent use of datapath APIs but an incorrect sequence of control API +calls may result in crashes, deadlocks, or race conditions. For example, +calling napi_disable() multiple times in a row will deadlock. + +Datapath API +------------ + +napi_schedule() is the basic method of scheduling a NAPI poll. +Drivers should call this function in their interrupt handler +(see :ref:`drv_sched` for more info). A successful call to napi_schedule() +will take ownership of the NAPI instance. + +Later, after NAPI is scheduled, the driver's poll method will be +called to process the events/packets. The method takes a ``budget`` +argument - drivers can process completions for any number of Tx +packets but should only process up to ``budget`` number of +Rx packets. Rx processing is usually much more expensive. + +In other words for Rx processing the ``budget`` argument limits how many +packets driver can process in a single poll. Rx specific APIs like page +pool or XDP cannot be used at all when ``budget`` is 0. +skb Tx processing should happen regardless of the ``budget``, but if +the argument is 0 driver cannot call any XDP (or page pool) APIs. + +.. warning:: + + The ``budget`` argument may be 0 if core tries to only process + skb Tx completions and no Rx or XDP packets. + +The poll method returns the amount of work done. If the driver still +has outstanding work to do (e.g. ``budget`` was exhausted) +the poll method should return exactly ``budget``. In that case, +the NAPI instance will be serviced/polled again (without the +need to be scheduled). + +If event processing has been completed (all outstanding packets +processed) the poll method should call napi_complete_done() +before returning. napi_complete_done() releases the ownership +of the instance. + +.. warning:: + + The case of finishing all events and using exactly ``budget`` + must be handled carefully. There is no way to report this + (rare) condition to the stack, so the driver must either + not call napi_complete_done() and wait to be called again, + or return ``budget - 1``. + + If the ``budget`` is 0 napi_complete_done() should never be called. + +Call sequence +------------- + +Drivers should not make assumptions about the exact sequencing +of calls. The poll method may be called without the driver scheduling +the instance (unless the instance is disabled). Similarly, +it's not guaranteed that the poll method will be called, even +if napi_schedule() succeeded (e.g. if the instance gets disabled). + +As mentioned in the :ref:`drv_ctrl` section - napi_disable() and subsequent +calls to the poll method only wait for the ownership of the instance +to be released, not for the poll method to exit. This means that +drivers should avoid accessing any data structures after calling +napi_complete_done(). + +.. _drv_sched: + +Scheduling and IRQ masking +-------------------------- + +Drivers should keep the interrupts masked after scheduling +the NAPI instance - until NAPI polling finishes any further +interrupts are unnecessary. + +Drivers which have to mask the interrupts explicitly (as opposed +to IRQ being auto-masked by the device) should use the napi_schedule_prep() +and __napi_schedule() calls: + +.. code-block:: c + + if (napi_schedule_prep(&v->napi)) { + mydrv_mask_rxtx_irq(v->idx); + /* schedule after masking to avoid races */ + __napi_schedule(&v->napi); + } + +IRQ should only be unmasked after a successful call to napi_complete_done(): + +.. code-block:: c + + if (budget && napi_complete_done(&v->napi, work_done)) { + mydrv_unmask_rxtx_irq(v->idx); + return min(work_done, budget - 1); + } + +napi_schedule_irqoff() is a variant of napi_schedule() which takes advantage +of guarantees given by being invoked in IRQ context (no need to +mask interrupts). Note that PREEMPT_RT forces all interrupts +to be threaded so the interrupt may need to be marked ``IRQF_NO_THREAD`` +to avoid issues on real-time kernel configurations. + +Instance to queue mapping +------------------------- + +Modern devices have multiple NAPI instances (struct napi_struct) per +interface. There is no strong requirement on how the instances are +mapped to queues and interrupts. NAPI is primarily a polling/processing +abstraction without specific user-facing semantics. That said, most networking +devices end up using NAPI in fairly similar ways. + +NAPI instances most often correspond 1:1:1 to interrupts and queue pairs +(queue pair is a set of a single Rx and single Tx queue). + +In less common cases a NAPI instance may be used for multiple queues +or Rx and Tx queues can be serviced by separate NAPI instances on a single +core. Regardless of the queue assignment, however, there is usually still +a 1:1 mapping between NAPI instances and interrupts. + +It's worth noting that the ethtool API uses a "channel" terminology where +each channel can be either ``rx``, ``tx`` or ``combined``. It's not clear +what constitutes a channel; the recommended interpretation is to understand +a channel as an IRQ/NAPI which services queues of a given type. For example, +a configuration of 1 ``rx``, 1 ``tx`` and 1 ``combined`` channel is expected +to utilize 3 interrupts, 2 Rx and 2 Tx queues. + +User API +======== + +User interactions with NAPI depend on NAPI instance ID. The instance IDs +are only visible to the user thru the ``SO_INCOMING_NAPI_ID`` socket option. +It's not currently possible to query IDs used by a given device. + +Software IRQ coalescing +----------------------- + +NAPI does not perform any explicit event coalescing by default. +In most scenarios batching happens due to IRQ coalescing which is done +by the device. There are cases where software coalescing is helpful. + +NAPI can be configured to arm a repoll timer instead of unmasking +the hardware interrupts as soon as all packets are processed. +The ``gro_flush_timeout`` sysfs configuration of the netdevice +is reused to control the delay of the timer, while +``napi_defer_hard_irqs`` controls the number of consecutive empty polls +before NAPI gives up and goes back to using hardware IRQs. + +.. _poll: + +Busy polling +------------ + +Busy polling allows a user process to check for incoming packets before +the device interrupt fires. As is the case with any busy polling it trades +off CPU cycles for lower latency (production uses of NAPI busy polling +are not well known). + +Busy polling is enabled by either setting ``SO_BUSY_POLL`` on +selected sockets or using the global ``net.core.busy_poll`` and +``net.core.busy_read`` sysctls. An io_uring API for NAPI busy polling +also exists. + +IRQ mitigation +--------------- + +While busy polling is supposed to be used by low latency applications, +a similar mechanism can be used for IRQ mitigation. + +Very high request-per-second applications (especially routing/forwarding +applications and especially applications using AF_XDP sockets) may not +want to be interrupted until they finish processing a request or a batch +of packets. + +Such applications can pledge to the kernel that they will perform a busy +polling operation periodically, and the driver should keep the device IRQs +permanently masked. This mode is enabled by using the ``SO_PREFER_BUSY_POLL`` +socket option. To avoid system misbehavior the pledge is revoked +if ``gro_flush_timeout`` passes without any busy poll call. + +The NAPI budget for busy polling is lower than the default (which makes +sense given the low latency intention of normal busy polling). This is +not the case with IRQ mitigation, however, so the budget can be adjusted +with the ``SO_BUSY_POLL_BUDGET`` socket option. + +.. _threaded: + +Threaded NAPI +------------- + +Threaded NAPI is an operating mode that uses dedicated kernel +threads rather than software IRQ context for NAPI processing. +The configuration is per netdevice and will affect all +NAPI instances of that device. Each NAPI instance will spawn a separate +thread (called ``napi/${ifc-name}-${napi-id}``). + +It is recommended to pin each kernel thread to a single CPU, the same +CPU as the CPU which services the interrupt. Note that the mapping +between IRQs and NAPI instances may not be trivial (and is driver +dependent). The NAPI instance IDs will be assigned in the opposite +order than the process IDs of the kernel threads. + +Threaded NAPI is controlled by writing 0/1 to the ``threaded`` file in +netdev's sysfs directory. + +.. rubric:: Footnotes + +.. [#] NAPI was originally referred to as New API in 2.4 Linux. diff --git a/Documentation/networking/net_dim.rst b/Documentation/networking/net_dim.rst new file mode 100644 index 0000000000..3bed9fd953 --- /dev/null +++ b/Documentation/networking/net_dim.rst @@ -0,0 +1,176 @@ +====================================================== +Net DIM - Generic Network Dynamic Interrupt Moderation +====================================================== + +:Author: Tal Gilboa <talgi@mellanox.com> + +.. contents:: :depth: 2 + +Assumptions +=========== + +This document assumes the reader has basic knowledge in network drivers +and in general interrupt moderation. + + +Introduction +============ + +Dynamic Interrupt Moderation (DIM) (in networking) refers to changing the +interrupt moderation configuration of a channel in order to optimize packet +processing. The mechanism includes an algorithm which decides if and how to +change moderation parameters for a channel, usually by performing an analysis on +runtime data sampled from the system. Net DIM is such a mechanism. In each +iteration of the algorithm, it analyses a given sample of the data, compares it +to the previous sample and if required, it can decide to change some of the +interrupt moderation configuration fields. The data sample is composed of data +bandwidth, the number of packets and the number of events. The time between +samples is also measured. Net DIM compares the current and the previous data and +returns an adjusted interrupt moderation configuration object. In some cases, +the algorithm might decide not to change anything. The configuration fields are +the minimum duration (microseconds) allowed between events and the maximum +number of wanted packets per event. The Net DIM algorithm ascribes importance to +increase bandwidth over reducing interrupt rate. + + +Net DIM Algorithm +================= + +Each iteration of the Net DIM algorithm follows these steps: + +#. Calculates new data sample. +#. Compares it to previous sample. +#. Makes a decision - suggests interrupt moderation configuration fields. +#. Applies a schedule work function, which applies suggested configuration. + +The first two steps are straightforward, both the new and the previous data are +supplied by the driver registered to Net DIM. The previous data is the new data +supplied to the previous iteration. The comparison step checks the difference +between the new and previous data and decides on the result of the last step. +A step would result as "better" if bandwidth increases and as "worse" if +bandwidth reduces. If there is no change in bandwidth, the packet rate is +compared in a similar fashion - increase == "better" and decrease == "worse". +In case there is no change in the packet rate as well, the interrupt rate is +compared. Here the algorithm tries to optimize for lower interrupt rate so an +increase in the interrupt rate is considered "worse" and a decrease is +considered "better". Step #2 has an optimization for avoiding false results: it +only considers a difference between samples as valid if it is greater than a +certain percentage. Also, since Net DIM does not measure anything by itself, it +assumes the data provided by the driver is valid. + +Step #3 decides on the suggested configuration based on the result from step #2 +and the internal state of the algorithm. The states reflect the "direction" of +the algorithm: is it going left (reducing moderation), right (increasing +moderation) or standing still. Another optimization is that if a decision +to stay still is made multiple times, the interval between iterations of the +algorithm would increase in order to reduce calculation overhead. Also, after +"parking" on one of the most left or most right decisions, the algorithm may +decide to verify this decision by taking a step in the other direction. This is +done in order to avoid getting stuck in a "deep sleep" scenario. Once a +decision is made, an interrupt moderation configuration is selected from +the predefined profiles. + +The last step is to notify the registered driver that it should apply the +suggested configuration. This is done by scheduling a work function, defined by +the Net DIM API and provided by the registered driver. + +As you can see, Net DIM itself does not actively interact with the system. It +would have trouble making the correct decisions if the wrong data is supplied to +it and it would be useless if the work function would not apply the suggested +configuration. This does, however, allow the registered driver some room for +manoeuvre as it may provide partial data or ignore the algorithm suggestion +under some conditions. + + +Registering a Network Device to DIM +=================================== + +Net DIM API exposes the main function net_dim(). +This function is the entry point to the Net +DIM algorithm and has to be called every time the driver would like to check if +it should change interrupt moderation parameters. The driver should provide two +data structures: :c:type:`struct dim <dim>` and +:c:type:`struct dim_sample <dim_sample>`. :c:type:`struct dim <dim>` +describes the state of DIM for a specific object (RX queue, TX queue, +other queues, etc.). This includes the current selected profile, previous data +samples, the callback function provided by the driver and more. +:c:type:`struct dim_sample <dim_sample>` describes a data sample, +which will be compared to the data sample stored in :c:type:`struct dim <dim>` +in order to decide on the algorithm's next +step. The sample should include bytes, packets and interrupts, measured by +the driver. + +In order to use Net DIM from a networking driver, the driver needs to call the +main net_dim() function. The recommended method is to call net_dim() on each +interrupt. Since Net DIM has a built-in moderation and it might decide to skip +iterations under certain conditions, there is no need to moderate the net_dim() +calls as well. As mentioned above, the driver needs to provide an object of type +:c:type:`struct dim <dim>` to the net_dim() function call. It is advised for +each entity using Net DIM to hold a :c:type:`struct dim <dim>` as part of its +data structure and use it as the main Net DIM API object. +The :c:type:`struct dim_sample <dim_sample>` should hold the latest +bytes, packets and interrupts count. No need to perform any calculations, just +include the raw data. + +The net_dim() call itself does not return anything. Instead Net DIM relies on +the driver to provide a callback function, which is called when the algorithm +decides to make a change in the interrupt moderation parameters. This callback +will be scheduled and run in a separate thread in order not to add overhead to +the data flow. After the work is done, Net DIM algorithm needs to be set to +the proper state in order to move to the next iteration. + + +Example +======= + +The following code demonstrates how to register a driver to Net DIM. The actual +usage is not complete but it should make the outline of the usage clear. + +.. code-block:: c + + #include <linux/dim.h> + + /* Callback for net DIM to schedule on a decision to change moderation */ + void my_driver_do_dim_work(struct work_struct *work) + { + /* Get struct dim from struct work_struct */ + struct dim *dim = container_of(work, struct dim, + work); + /* Do interrupt moderation related stuff */ + ... + + /* Signal net DIM work is done and it should move to next iteration */ + dim->state = DIM_START_MEASURE; + } + + /* My driver's interrupt handler */ + int my_driver_handle_interrupt(struct my_driver_entity *my_entity, ...) + { + ... + /* A struct to hold current measured data */ + struct dim_sample dim_sample; + ... + /* Initiate data sample struct with current data */ + dim_update_sample(my_entity->events, + my_entity->packets, + my_entity->bytes, + &dim_sample); + /* Call net DIM */ + net_dim(&my_entity->dim, dim_sample); + ... + } + + /* My entity's initialization function (my_entity was already allocated) */ + int my_driver_init_my_entity(struct my_driver_entity *my_entity, ...) + { + ... + /* Initiate struct work_struct with my driver's callback function */ + INIT_WORK(&my_entity->dim.work, my_driver_do_dim_work); + ... + } + +Dynamic Interrupt Moderation (DIM) library API +============================================== + +.. kernel-doc:: include/linux/dim.h + :internal: diff --git a/Documentation/networking/net_failover.rst b/Documentation/networking/net_failover.rst new file mode 100644 index 0000000000..f4e1b4e07a --- /dev/null +++ b/Documentation/networking/net_failover.rst @@ -0,0 +1,184 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============ +NET_FAILOVER +============ + +Overview +======== + +The net_failover driver provides an automated failover mechanism via APIs +to create and destroy a failover master netdev and manages a primary and +standby slave netdevs that get registered via the generic failover +infrastructure. + +The failover netdev acts a master device and controls 2 slave devices. The +original paravirtual interface is registered as 'standby' slave netdev and +a passthru/vf device with the same MAC gets registered as 'primary' slave +netdev. Both 'standby' and 'failover' netdevs are associated with the same +'pci' device. The user accesses the network interface via 'failover' netdev. +The 'failover' netdev chooses 'primary' netdev as default for transmits when +it is available with link up and running. + +This can be used by paravirtual drivers to enable an alternate low latency +datapath. It also enables hypervisor controlled live migration of a VM with +direct attached VF by failing over to the paravirtual datapath when the VF +is unplugged. + +virtio-net accelerated datapath: STANDBY mode +============================================= + +net_failover enables hypervisor controlled accelerated datapath to virtio-net +enabled VMs in a transparent manner with no/minimal guest userspace changes. + +To support this, the hypervisor needs to enable VIRTIO_NET_F_STANDBY +feature on the virtio-net interface and assign the same MAC address to both +virtio-net and VF interfaces. + +Here is an example libvirt XML snippet that shows such configuration: +:: + + <interface type='network'> + <mac address='52:54:00:00:12:53'/> + <source network='enp66s0f0_br'/> + <target dev='tap01'/> + <model type='virtio'/> + <driver name='vhost' queues='4'/> + <link state='down'/> + <teaming type='persistent'/> + <alias name='ua-backup0'/> + </interface> + <interface type='hostdev' managed='yes'> + <mac address='52:54:00:00:12:53'/> + <source> + <address type='pci' domain='0x0000' bus='0x42' slot='0x02' function='0x5'/> + </source> + <teaming type='transient' persistent='ua-backup0'/> + </interface> + +In this configuration, the first device definition is for the virtio-net +interface and this acts as the 'persistent' device indicating that this +interface will always be plugged in. This is specified by the 'teaming' tag with +required attribute type having value 'persistent'. The link state for the +virtio-net device is set to 'down' to ensure that the 'failover' netdev prefers +the VF passthrough device for normal communication. The virtio-net device will +be brought UP during live migration to allow uninterrupted communication. + +The second device definition is for the VF passthrough interface. Here the +'teaming' tag is provided with type 'transient' indicating that this device may +periodically be unplugged. A second attribute - 'persistent' is provided and +points to the alias name declared for the virtio-net device. + +Booting a VM with the above configuration will result in the following 3 +interfaces created in the VM: +:: + + 4: ens10: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000 + link/ether 52:54:00:00:12:53 brd ff:ff:ff:ff:ff:ff + inet 192.168.12.53/24 brd 192.168.12.255 scope global dynamic ens10 + valid_lft 42482sec preferred_lft 42482sec + inet6 fe80::97d8:db2:8c10:b6d6/64 scope link + valid_lft forever preferred_lft forever + 5: ens10nsby: <BROADCAST,MULTICAST> mtu 1500 qdisc fq_codel master ens10 state DOWN group default qlen 1000 + link/ether 52:54:00:00:12:53 brd ff:ff:ff:ff:ff:ff + 7: ens11: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master ens10 state UP group default qlen 1000 + link/ether 52:54:00:00:12:53 brd ff:ff:ff:ff:ff:ff + +Here, ens10 is the 'failover' master interface, ens10nsby is the slave 'standby' +virtio-net interface, and ens11 is the slave 'primary' VF passthrough interface. + +One point to note here is that some user space network configuration daemons +like systemd-networkd, ifupdown, etc, do not understand the 'net_failover' +device; and on the first boot, the VM might end up with both 'failover' device +and VF acquiring IP addresses (either same or different) from the DHCP server. +This will result in lack of connectivity to the VM. So some tweaks might be +needed to these network configuration daemons to make sure that an IP is +received only on the 'failover' device. + +Below is the patch snippet used with 'cloud-ifupdown-helper' script found on +Debian cloud images: + +:: + @@ -27,6 +27,8 @@ do_setup() { + local working="$cfgdir/.$INTERFACE" + local final="$cfgdir/$INTERFACE" + + + if [ -d "/sys/class/net/${INTERFACE}/master" ]; then exit 0; fi + + + if ifup --no-act "$INTERFACE" > /dev/null 2>&1; then + # interface is already known to ifupdown, no need to generate cfg + log "Skipping configuration generation for $INTERFACE" + + +Live Migration of a VM with SR-IOV VF & virtio-net in STANDBY mode +================================================================== + +net_failover also enables hypervisor controlled live migration to be supported +with VMs that have direct attached SR-IOV VF devices by automatic failover to +the paravirtual datapath when the VF is unplugged. + +Here is a sample script that shows the steps to initiate live migration from +the source hypervisor. Note: It is assumed that the VM is connected to a +software bridge 'br0' which has a single VF attached to it along with the vnet +device to the VM. This is not the VF that was passthrough'd to the VM (seen in +the vf.xml file). +:: + + # cat vf.xml + <interface type='hostdev' managed='yes'> + <mac address='52:54:00:00:12:53'/> + <source> + <address type='pci' domain='0x0000' bus='0x42' slot='0x02' function='0x5'/> + </source> + <teaming type='transient' persistent='ua-backup0'/> + </interface> + + # Source Hypervisor migrate.sh + #!/bin/bash + + DOMAIN=vm-01 + PF=ens6np0 + VF=ens6v1 # VF attached to the bridge. + VF_NUM=1 + TAP_IF=vmtap01 # virtio-net interface in the VM. + VF_XML=vf.xml + + MAC=52:54:00:00:12:53 + ZERO_MAC=00:00:00:00:00:00 + + # Set the virtio-net interface up. + virsh domif-setlink $DOMAIN $TAP_IF up + + # Remove the VF that was passthrough'd to the VM. + virsh detach-device --live --config $DOMAIN $VF_XML + + ip link set $PF vf $VF_NUM mac $ZERO_MAC + + # Add FDB entry for traffic to continue going to the VM via + # the VF -> br0 -> vnet interface path. + bridge fdb add $MAC dev $VF + bridge fdb add $MAC dev $TAP_IF master + + # Migrate the VM + virsh migrate --live --persistent $DOMAIN qemu+ssh://$REMOTE_HOST/system + + # Clean up FDB entries after migration completes. + bridge fdb del $MAC dev $VF + bridge fdb del $MAC dev $TAP_IF master + +On the destination hypervisor, a shared bridge 'br0' is created before migration +starts, and a VF from the destination PF is added to the bridge. Similarly an +appropriate FDB entry is added. + +The following script is executed on the destination hypervisor once migration +completes, and it reattaches the VF to the VM and brings down the virtio-net +interface. + +:: + # reattach-vf.sh + #!/bin/bash + + bridge fdb del 52:54:00:00:12:53 dev ens36v0 + bridge fdb del 52:54:00:00:12:53 dev vmtap01 master + virsh attach-device --config --live vm01 vf.xml + virsh domif-setlink vm01 vmtap01 down diff --git a/Documentation/networking/netconsole.rst b/Documentation/networking/netconsole.rst new file mode 100644 index 0000000000..7a9de0568e --- /dev/null +++ b/Documentation/networking/netconsole.rst @@ -0,0 +1,248 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========== +Netconsole +========== + + +started by Ingo Molnar <mingo@redhat.com>, 2001.09.17 + +2.6 port and netpoll api by Matt Mackall <mpm@selenic.com>, Sep 9 2003 + +IPv6 support by Cong Wang <xiyou.wangcong@gmail.com>, Jan 1 2013 + +Extended console support by Tejun Heo <tj@kernel.org>, May 1 2015 + +Release prepend support by Breno Leitao <leitao@debian.org>, Jul 7 2023 + +Please send bug reports to Matt Mackall <mpm@selenic.com> +Satyam Sharma <satyam.sharma@gmail.com>, and Cong Wang <xiyou.wangcong@gmail.com> + +Introduction: +============= + +This module logs kernel printk messages over UDP allowing debugging of +problem where disk logging fails and serial consoles are impractical. + +It can be used either built-in or as a module. As a built-in, +netconsole initializes immediately after NIC cards and will bring up +the specified interface as soon as possible. While this doesn't allow +capture of early kernel panics, it does capture most of the boot +process. + +Sender and receiver configuration: +================================== + +It takes a string configuration parameter "netconsole" in the +following format:: + + netconsole=[+][r][src-port]@[src-ip]/[<dev>],[tgt-port]@<tgt-ip>/[tgt-macaddr] + + where + + if present, enable extended console support + r if present, prepend kernel version (release) to the message + src-port source for UDP packets (defaults to 6665) + src-ip source IP to use (interface address) + dev network interface (eth0) + tgt-port port for logging agent (6666) + tgt-ip IP address for logging agent + tgt-macaddr ethernet MAC address for logging agent (broadcast) + +Examples:: + + linux netconsole=4444@10.0.0.1/eth1,9353@10.0.0.2/12:34:56:78:9a:bc + +or:: + + insmod netconsole netconsole=@/,@10.0.0.2/ + +or using IPv6:: + + insmod netconsole netconsole=@/,@fd00:1:2:3::1/ + +It also supports logging to multiple remote agents by specifying +parameters for the multiple agents separated by semicolons and the +complete string enclosed in "quotes", thusly:: + + modprobe netconsole netconsole="@/,@10.0.0.2/;@/eth1,6892@10.0.0.3/" + +Built-in netconsole starts immediately after the TCP stack is +initialized and attempts to bring up the supplied dev at the supplied +address. + +The remote host has several options to receive the kernel messages, +for example: + +1) syslogd + +2) netcat + + On distributions using a BSD-based netcat version (e.g. Fedora, + openSUSE and Ubuntu) the listening port must be specified without + the -p switch:: + + nc -u -l -p <port>' / 'nc -u -l <port> + + or:: + + netcat -u -l -p <port>' / 'netcat -u -l <port> + +3) socat + +:: + + socat udp-recv:<port> - + +Dynamic reconfiguration: +======================== + +Dynamic reconfigurability is a useful addition to netconsole that enables +remote logging targets to be dynamically added, removed, or have their +parameters reconfigured at runtime from a configfs-based userspace interface. +[ Note that the parameters of netconsole targets that were specified/created +from the boot/module option are not exposed via this interface, and hence +cannot be modified dynamically. ] + +To include this feature, select CONFIG_NETCONSOLE_DYNAMIC when building the +netconsole module (or kernel, if netconsole is built-in). + +Some examples follow (where configfs is mounted at the /sys/kernel/config +mountpoint). + +To add a remote logging target (target names can be arbitrary):: + + cd /sys/kernel/config/netconsole/ + mkdir target1 + +Note that newly created targets have default parameter values (as mentioned +above) and are disabled by default -- they must first be enabled by writing +"1" to the "enabled" attribute (usually after setting parameters accordingly) +as described below. + +To remove a target:: + + rmdir /sys/kernel/config/netconsole/othertarget/ + +The interface exposes these parameters of a netconsole target to userspace: + + ============== ================================= ============ + enabled Is this target currently enabled? (read-write) + extended Extended mode enabled (read-write) + release Prepend kernel release to message (read-write) + dev_name Local network interface name (read-write) + local_port Source UDP port to use (read-write) + remote_port Remote agent's UDP port (read-write) + local_ip Source IP address to use (read-write) + remote_ip Remote agent's IP address (read-write) + local_mac Local interface's MAC address (read-only) + remote_mac Remote agent's MAC address (read-write) + ============== ================================= ============ + +The "enabled" attribute is also used to control whether the parameters of +a target can be updated or not -- you can modify the parameters of only +disabled targets (i.e. if "enabled" is 0). + +To update a target's parameters:: + + cat enabled # check if enabled is 1 + echo 0 > enabled # disable the target (if required) + echo eth2 > dev_name # set local interface + echo 10.0.0.4 > remote_ip # update some parameter + echo cb:a9:87:65:43:21 > remote_mac # update more parameters + echo 1 > enabled # enable target again + +You can also update the local interface dynamically. This is especially +useful if you want to use interfaces that have newly come up (and may not +have existed when netconsole was loaded / initialized). + +Extended console: +================= + +If '+' is prefixed to the configuration line or "extended" config file +is set to 1, extended console support is enabled. An example boot +param follows:: + + linux netconsole=+4444@10.0.0.1/eth1,9353@10.0.0.2/12:34:56:78:9a:bc + +Log messages are transmitted with extended metadata header in the +following format which is the same as /dev/kmsg:: + + <level>,<sequnum>,<timestamp>,<contflag>;<message text> + +If 'r' (release) feature is enabled, the kernel release version is +prepended to the start of the message. Example:: + + 6.4.0,6,444,501151268,-;netconsole: network logging started + +Non printable characters in <message text> are escaped using "\xff" +notation. If the message contains optional dictionary, verbatim +newline is used as the delimiter. + +If a message doesn't fit in certain number of bytes (currently 1000), +the message is split into multiple fragments by netconsole. These +fragments are transmitted with "ncfrag" header field added:: + + ncfrag=<byte-offset>/<total-bytes> + +For example, assuming a lot smaller chunk size, a message "the first +chunk, the 2nd chunk." may be split as follows:: + + 6,416,1758426,-,ncfrag=0/31;the first chunk, + 6,416,1758426,-,ncfrag=16/31; the 2nd chunk. + +Miscellaneous notes: +==================== + +.. Warning:: + + the default target ethernet setting uses the broadcast + ethernet address to send packets, which can cause increased load on + other systems on the same ethernet segment. + +.. Tip:: + + some LAN switches may be configured to suppress ethernet broadcasts + so it is advised to explicitly specify the remote agents' MAC addresses + from the config parameters passed to netconsole. + +.. Tip:: + + to find out the MAC address of, say, 10.0.0.2, you may try using:: + + ping -c 1 10.0.0.2 ; /sbin/arp -n | grep 10.0.0.2 + +.. Tip:: + + in case the remote logging agent is on a separate LAN subnet than + the sender, it is suggested to try specifying the MAC address of the + default gateway (you may use /sbin/route -n to find it out) as the + remote MAC address instead. + +.. note:: + + the network device (eth1 in the above case) can run any kind + of other network traffic, netconsole is not intrusive. Netconsole + might cause slight delays in other traffic if the volume of kernel + messages is high, but should have no other impact. + +.. note:: + + if you find that the remote logging agent is not receiving or + printing all messages from the sender, it is likely that you have set + the "console_loglevel" parameter (on the sender) to only send high + priority messages to the console. You can change this at runtime using:: + + dmesg -n 8 + + or by specifying "debug" on the kernel command line at boot, to send + all kernel messages to the console. A specific value for this parameter + can also be set using the "loglevel" kernel boot option. See the + dmesg(8) man page and Documentation/admin-guide/kernel-parameters.rst + for details. + +Netconsole was designed to be as instantaneous as possible, to +enable the logging of even the most critical kernel bugs. It works +from IRQ contexts as well, and does not enable interrupts while +sending packets. Due to these unique needs, configuration cannot +be more automatic, and some fundamental limitations will remain: +only IP networks, UDP packets and ethernet devices are supported. diff --git a/Documentation/networking/netdev-features.rst b/Documentation/networking/netdev-features.rst new file mode 100644 index 0000000000..d7b15bb64d --- /dev/null +++ b/Documentation/networking/netdev-features.rst @@ -0,0 +1,205 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================================================== +Netdev features mess and how to get out from it alive +===================================================== + +Author: + Michał Mirosław <mirq-linux@rere.qmqm.pl> + + + +Part I: Feature sets +==================== + +Long gone are the days when a network card would just take and give packets +verbatim. Today's devices add multiple features and bugs (read: offloads) +that relieve an OS of various tasks like generating and checking checksums, +splitting packets, classifying them. Those capabilities and their state +are commonly referred to as netdev features in Linux kernel world. + +There are currently three sets of features relevant to the driver, and +one used internally by network core: + + 1. netdev->hw_features set contains features whose state may possibly + be changed (enabled or disabled) for a particular device by user's + request. This set should be initialized in ndo_init callback and not + changed later. + + 2. netdev->features set contains features which are currently enabled + for a device. This should be changed only by network core or in + error paths of ndo_set_features callback. + + 3. netdev->vlan_features set contains features whose state is inherited + by child VLAN devices (limits netdev->features set). This is currently + used for all VLAN devices whether tags are stripped or inserted in + hardware or software. + + 4. netdev->wanted_features set contains feature set requested by user. + This set is filtered by ndo_fix_features callback whenever it or + some device-specific conditions change. This set is internal to + networking core and should not be referenced in drivers. + + + +Part II: Controlling enabled features +===================================== + +When current feature set (netdev->features) is to be changed, new set +is calculated and filtered by calling ndo_fix_features callback +and netdev_fix_features(). If the resulting set differs from current +set, it is passed to ndo_set_features callback and (if the callback +returns success) replaces value stored in netdev->features. +NETDEV_FEAT_CHANGE notification is issued after that whenever current +set might have changed. + +The following events trigger recalculation: + 1. device's registration, after ndo_init returned success + 2. user requested changes in features state + 3. netdev_update_features() is called + +ndo_*_features callbacks are called with rtnl_lock held. Missing callbacks +are treated as always returning success. + +A driver that wants to trigger recalculation must do so by calling +netdev_update_features() while holding rtnl_lock. This should not be done +from ndo_*_features callbacks. netdev->features should not be modified by +driver except by means of ndo_fix_features callback. + + + +Part III: Implementation hints +============================== + + * ndo_fix_features: + +All dependencies between features should be resolved here. The resulting +set can be reduced further by networking core imposed limitations (as coded +in netdev_fix_features()). For this reason it is safer to disable a feature +when its dependencies are not met instead of forcing the dependency on. + +This callback should not modify hardware nor driver state (should be +stateless). It can be called multiple times between successive +ndo_set_features calls. + +Callback must not alter features contained in NETIF_F_SOFT_FEATURES or +NETIF_F_NEVER_CHANGE sets. The exception is NETIF_F_VLAN_CHALLENGED but +care must be taken as the change won't affect already configured VLANs. + + * ndo_set_features: + +Hardware should be reconfigured to match passed feature set. The set +should not be altered unless some error condition happens that can't +be reliably detected in ndo_fix_features. In this case, the callback +should update netdev->features to match resulting hardware state. +Errors returned are not (and cannot be) propagated anywhere except dmesg. +(Note: successful return is zero, >0 means silent error.) + + + +Part IV: Features +================= + +For current list of features, see include/linux/netdev_features.h. +This section describes semantics of some of them. + + * Transmit checksumming + +For complete description, see comments near the top of include/linux/skbuff.h. + +Note: NETIF_F_HW_CSUM is a superset of NETIF_F_IP_CSUM + NETIF_F_IPV6_CSUM. +It means that device can fill TCP/UDP-like checksum anywhere in the packets +whatever headers there might be. + + * Transmit TCP segmentation offload + +NETIF_F_TSO_ECN means that hardware can properly split packets with CWR bit +set, be it TCPv4 (when NETIF_F_TSO is enabled) or TCPv6 (NETIF_F_TSO6). + + * Transmit UDP segmentation offload + +NETIF_F_GSO_UDP_L4 accepts a single UDP header with a payload that exceeds +gso_size. On segmentation, it segments the payload on gso_size boundaries and +replicates the network and UDP headers (fixing up the last one if less than +gso_size). + + * Transmit DMA from high memory + +On platforms where this is relevant, NETIF_F_HIGHDMA signals that +ndo_start_xmit can handle skbs with frags in high memory. + + * Transmit scatter-gather + +Those features say that ndo_start_xmit can handle fragmented skbs: +NETIF_F_SG --- paged skbs (skb_shinfo()->frags), NETIF_F_FRAGLIST --- +chained skbs (skb->next/prev list). + + * Software features + +Features contained in NETIF_F_SOFT_FEATURES are features of networking +stack. Driver should not change behaviour based on them. + + * LLTX driver (deprecated for hardware drivers) + +NETIF_F_LLTX is meant to be used by drivers that don't need locking at all, +e.g. software tunnels. + +This is also used in a few legacy drivers that implement their +own locking, don't use it for new (hardware) drivers. + + * netns-local device + +NETIF_F_NETNS_LOCAL is set for devices that are not allowed to move between +network namespaces (e.g. loopback). + +Don't use it in drivers. + + * VLAN challenged + +NETIF_F_VLAN_CHALLENGED should be set for devices which can't cope with VLAN +headers. Some drivers set this because the cards can't handle the bigger MTU. +[FIXME: Those cases could be fixed in VLAN code by allowing only reduced-MTU +VLANs. This may be not useful, though.] + +* rx-fcs + +This requests that the NIC append the Ethernet Frame Checksum (FCS) +to the end of the skb data. This allows sniffers and other tools to +read the CRC recorded by the NIC on receipt of the packet. + +* rx-all + +This requests that the NIC receive all possible frames, including errored +frames (such as bad FCS, etc). This can be helpful when sniffing a link with +bad packets on it. Some NICs may receive more packets if also put into normal +PROMISC mode. + +* rx-gro-hw + +This requests that the NIC enables Hardware GRO (generic receive offload). +Hardware GRO is basically the exact reverse of TSO, and is generally +stricter than Hardware LRO. A packet stream merged by Hardware GRO must +be re-segmentable by GSO or TSO back to the exact original packet stream. +Hardware GRO is dependent on RXCSUM since every packet successfully merged +by hardware must also have the checksum verified by hardware. + +* hsr-tag-ins-offload + +This should be set for devices which insert an HSR (High-availability Seamless +Redundancy) or PRP (Parallel Redundancy Protocol) tag automatically. + +* hsr-tag-rm-offload + +This should be set for devices which remove HSR (High-availability Seamless +Redundancy) or PRP (Parallel Redundancy Protocol) tags automatically. + +* hsr-fwd-offload + +This should be set for devices which forward HSR (High-availability Seamless +Redundancy) frames from one port to another in hardware. + +* hsr-dup-offload + +This should be set for devices which duplicate outgoing HSR (High-availability +Seamless Redundancy) or PRP (Parallel Redundancy Protocol) tags automatically +frames in hardware. diff --git a/Documentation/networking/netdevices.rst b/Documentation/networking/netdevices.rst new file mode 100644 index 0000000000..9e4cccb90b --- /dev/null +++ b/Documentation/networking/netdevices.rst @@ -0,0 +1,299 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================================== +Network Devices, the Kernel, and You! +===================================== + + +Introduction +============ +The following is a random collection of documentation regarding +network devices. + +struct net_device lifetime rules +================================ +Network device structures need to persist even after module is unloaded and +must be allocated with alloc_netdev_mqs() and friends. +If device has registered successfully, it will be freed on last use +by free_netdev(). This is required to handle the pathological case cleanly +(example: ``rmmod mydriver </sys/class/net/myeth/mtu``) + +alloc_netdev_mqs() / alloc_netdev() reserve extra space for driver +private data which gets freed when the network device is freed. If +separately allocated data is attached to the network device +(netdev_priv()) then it is up to the module exit handler to free that. + +There are two groups of APIs for registering struct net_device. +First group can be used in normal contexts where ``rtnl_lock`` is not already +held: register_netdev(), unregister_netdev(). +Second group can be used when ``rtnl_lock`` is already held: +register_netdevice(), unregister_netdevice(), free_netdevice(). + +Simple drivers +-------------- + +Most drivers (especially device drivers) handle lifetime of struct net_device +in context where ``rtnl_lock`` is not held (e.g. driver probe and remove paths). + +In that case the struct net_device registration is done using +the register_netdev(), and unregister_netdev() functions: + +.. code-block:: c + + int probe() + { + struct my_device_priv *priv; + int err; + + dev = alloc_netdev_mqs(...); + if (!dev) + return -ENOMEM; + priv = netdev_priv(dev); + + /* ... do all device setup before calling register_netdev() ... + */ + + err = register_netdev(dev); + if (err) + goto err_undo; + + /* net_device is visible to the user! */ + + err_undo: + /* ... undo the device setup ... */ + free_netdev(dev); + return err; + } + + void remove() + { + unregister_netdev(dev); + free_netdev(dev); + } + +Note that after calling register_netdev() the device is visible in the system. +Users can open it and start sending / receiving traffic immediately, +or run any other callback, so all initialization must be done prior to +registration. + +unregister_netdev() closes the device and waits for all users to be done +with it. The memory of struct net_device itself may still be referenced +by sysfs but all operations on that device will fail. + +free_netdev() can be called after unregister_netdev() returns on when +register_netdev() failed. + +Device management under RTNL +---------------------------- + +Registering struct net_device while in context which already holds +the ``rtnl_lock`` requires extra care. In those scenarios most drivers +will want to make use of struct net_device's ``needs_free_netdev`` +and ``priv_destructor`` members for freeing of state. + +Example flow of netdev handling under ``rtnl_lock``: + +.. code-block:: c + + static void my_setup(struct net_device *dev) + { + dev->needs_free_netdev = true; + } + + static void my_destructor(struct net_device *dev) + { + some_obj_destroy(priv->obj); + some_uninit(priv); + } + + int create_link() + { + struct my_device_priv *priv; + int err; + + ASSERT_RTNL(); + + dev = alloc_netdev(sizeof(*priv), "net%d", NET_NAME_UNKNOWN, my_setup); + if (!dev) + return -ENOMEM; + priv = netdev_priv(dev); + + /* Implicit constructor */ + err = some_init(priv); + if (err) + goto err_free_dev; + + priv->obj = some_obj_create(); + if (!priv->obj) { + err = -ENOMEM; + goto err_some_uninit; + } + /* End of constructor, set the destructor: */ + dev->priv_destructor = my_destructor; + + err = register_netdevice(dev); + if (err) + /* register_netdevice() calls destructor on failure */ + goto err_free_dev; + + /* If anything fails now unregister_netdevice() (or unregister_netdev()) + * will take care of calling my_destructor and free_netdev(). + */ + + return 0; + + err_some_uninit: + some_uninit(priv); + err_free_dev: + free_netdev(dev); + return err; + } + +If struct net_device.priv_destructor is set it will be called by the core +some time after unregister_netdevice(), it will also be called if +register_netdevice() fails. The callback may be invoked with or without +``rtnl_lock`` held. + +There is no explicit constructor callback, driver "constructs" the private +netdev state after allocating it and before registration. + +Setting struct net_device.needs_free_netdev makes core call free_netdevice() +automatically after unregister_netdevice() when all references to the device +are gone. It only takes effect after a successful call to register_netdevice() +so if register_netdevice() fails driver is responsible for calling +free_netdev(). + +free_netdev() is safe to call on error paths right after unregister_netdevice() +or when register_netdevice() fails. Parts of netdev (de)registration process +happen after ``rtnl_lock`` is released, therefore in those cases free_netdev() +will defer some of the processing until ``rtnl_lock`` is released. + +Devices spawned from struct rtnl_link_ops should never free the +struct net_device directly. + +.ndo_init and .ndo_uninit +~~~~~~~~~~~~~~~~~~~~~~~~~ + +``.ndo_init`` and ``.ndo_uninit`` callbacks are called during net_device +registration and de-registration, under ``rtnl_lock``. Drivers can use +those e.g. when parts of their init process need to run under ``rtnl_lock``. + +``.ndo_init`` runs before device is visible in the system, ``.ndo_uninit`` +runs during de-registering after device is closed but other subsystems +may still have outstanding references to the netdevice. + +MTU +=== +Each network device has a Maximum Transfer Unit. The MTU does not +include any link layer protocol overhead. Upper layer protocols must +not pass a socket buffer (skb) to a device to transmit with more data +than the mtu. The MTU does not include link layer header overhead, so +for example on Ethernet if the standard MTU is 1500 bytes used, the +actual skb will contain up to 1514 bytes because of the Ethernet +header. Devices should allow for the 4 byte VLAN header as well. + +Segmentation Offload (GSO, TSO) is an exception to this rule. The +upper layer protocol may pass a large socket buffer to the device +transmit routine, and the device will break that up into separate +packets based on the current MTU. + +MTU is symmetrical and applies both to receive and transmit. A device +must be able to receive at least the maximum size packet allowed by +the MTU. A network device may use the MTU as mechanism to size receive +buffers, but the device should allow packets with VLAN header. With +standard Ethernet mtu of 1500 bytes, the device should allow up to +1518 byte packets (1500 + 14 header + 4 tag). The device may either: +drop, truncate, or pass up oversize packets, but dropping oversize +packets is preferred. + + +struct net_device synchronization rules +======================================= +ndo_open: + Synchronization: rtnl_lock() semaphore. + Context: process + +ndo_stop: + Synchronization: rtnl_lock() semaphore. + Context: process + Note: netif_running() is guaranteed false + +ndo_do_ioctl: + Synchronization: rtnl_lock() semaphore. + Context: process + + This is only called by network subsystems internally, + not by user space calling ioctl as it was in before + linux-5.14. + +ndo_siocbond: + Synchronization: rtnl_lock() semaphore. + Context: process + + Used by the bonding driver for the SIOCBOND family of + ioctl commands. + +ndo_siocwandev: + Synchronization: rtnl_lock() semaphore. + Context: process + + Used by the drivers/net/wan framework to handle + the SIOCWANDEV ioctl with the if_settings structure. + +ndo_siocdevprivate: + Synchronization: rtnl_lock() semaphore. + Context: process + + This is used to implement SIOCDEVPRIVATE ioctl helpers. + These should not be added to new drivers, so don't use. + +ndo_eth_ioctl: + Synchronization: rtnl_lock() semaphore. + Context: process + +ndo_get_stats: + Synchronization: rtnl_lock() semaphore, dev_base_lock rwlock, or RCU. + Context: atomic (can't sleep under rwlock or RCU) + +ndo_start_xmit: + Synchronization: __netif_tx_lock spinlock. + + When the driver sets NETIF_F_LLTX in dev->features this will be + called without holding netif_tx_lock. In this case the driver + has to lock by itself when needed. + The locking there should also properly protect against + set_rx_mode. WARNING: use of NETIF_F_LLTX is deprecated. + Don't use it for new drivers. + + Context: Process with BHs disabled or BH (timer), + will be called with interrupts disabled by netconsole. + + Return codes: + + * NETDEV_TX_OK everything ok. + * NETDEV_TX_BUSY Cannot transmit packet, try later + Usually a bug, means queue start/stop flow control is broken in + the driver. Note: the driver must NOT put the skb in its DMA ring. + +ndo_tx_timeout: + Synchronization: netif_tx_lock spinlock; all TX queues frozen. + Context: BHs disabled + Notes: netif_queue_stopped() is guaranteed true + +ndo_set_rx_mode: + Synchronization: netif_addr_lock spinlock. + Context: BHs disabled + +struct napi_struct synchronization rules +======================================== +napi->poll: + Synchronization: + NAPI_STATE_SCHED bit in napi->state. Device + driver's ndo_stop method will invoke napi_disable() on + all NAPI instances which will do a sleeping poll on the + NAPI_STATE_SCHED napi->state bit, waiting for all pending + NAPI activity to cease. + + Context: + softirq + will be called with interrupts disabled by netconsole. diff --git a/Documentation/networking/netfilter-sysctl.rst b/Documentation/networking/netfilter-sysctl.rst new file mode 100644 index 0000000000..beb6d7b275 --- /dev/null +++ b/Documentation/networking/netfilter-sysctl.rst @@ -0,0 +1,17 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================= +Netfilter Sysfs variables +========================= + +/proc/sys/net/netfilter/* Variables: +==================================== + +nf_log_all_netns - BOOLEAN + - 0 - disabled (default) + - not 0 - enabled + + By default, only init_net namespace can log packets into kernel log + with LOG target; this aims to prevent containers from flooding host + kernel log. If enabled, this target also works in other network + namespaces. This variable is only accessible from init_net. diff --git a/Documentation/networking/netif-msg.rst b/Documentation/networking/netif-msg.rst new file mode 100644 index 0000000000..b20d265a73 --- /dev/null +++ b/Documentation/networking/netif-msg.rst @@ -0,0 +1,95 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=============== +NETIF Msg Level +=============== + +The design of the network interface message level setting. + +History +------- + + The design of the debugging message interface was guided and + constrained by backwards compatibility previous practice. It is useful + to understand the history and evolution in order to understand current + practice and relate it to older driver source code. + + From the beginning of Linux, each network device driver has had a local + integer variable that controls the debug message level. The message + level ranged from 0 to 7, and monotonically increased in verbosity. + + The message level was not precisely defined past level 3, but were + always implemented within +-1 of the specified level. Drivers tended + to shed the more verbose level messages as they matured. + + - 0 Minimal messages, only essential information on fatal errors. + - 1 Standard messages, initialization status. No run-time messages + - 2 Special media selection messages, generally timer-driver. + - 3 Interface starts and stops, including normal status messages + - 4 Tx and Rx frame error messages, and abnormal driver operation + - 5 Tx packet queue information, interrupt events. + - 6 Status on each completed Tx packet and received Rx packets + - 7 Initial contents of Tx and Rx packets + + Initially this message level variable was uniquely named in each driver + e.g. "lance_debug", so that a kernel symbolic debugger could locate and + modify the setting. When kernel modules became common, the variables + were consistently renamed to "debug" and allowed to be set as a module + parameter. + + This approach worked well. However there is always a demand for + additional features. Over the years the following emerged as + reasonable and easily implemented enhancements + + - Using an ioctl() call to modify the level. + - Per-interface rather than per-driver message level setting. + - More selective control over the type of messages emitted. + + The netif_msg recommendation adds these features with only a minor + complexity and code size increase. + + The recommendation is the following points + + - Retaining the per-driver integer variable "debug" as a module + parameter with a default level of '1'. + + - Adding a per-interface private variable named "msg_enable". The + variable is a bit map rather than a level, and is initialized as:: + + 1 << debug + + Or more precisely:: + + debug < 0 ? 0 : 1 << min(sizeof(int)-1, debug) + + Messages should changes from:: + + if (debug > 1) + printk(MSG_DEBUG "%s: ... + + to:: + + if (np->msg_enable & NETIF_MSG_LINK) + printk(MSG_DEBUG "%s: ... + + +The set of message levels is named + + + ========= =================== ============ + Old level Name Bit position + ========= =================== ============ + 0 NETIF_MSG_DRV 0x0001 + 1 NETIF_MSG_PROBE 0x0002 + 2 NETIF_MSG_LINK 0x0004 + 2 NETIF_MSG_TIMER 0x0004 + 3 NETIF_MSG_IFDOWN 0x0008 + 3 NETIF_MSG_IFUP 0x0008 + 4 NETIF_MSG_RX_ERR 0x0010 + 4 NETIF_MSG_TX_ERR 0x0010 + 5 NETIF_MSG_TX_QUEUED 0x0020 + 5 NETIF_MSG_INTR 0x0020 + 6 NETIF_MSG_TX_DONE 0x0040 + 6 NETIF_MSG_RX_STATUS 0x0040 + 7 NETIF_MSG_PKTDATA 0x0080 + ========= =================== ============ diff --git a/Documentation/networking/nexthop-group-resilient.rst b/Documentation/networking/nexthop-group-resilient.rst new file mode 100644 index 0000000000..fabecee24d --- /dev/null +++ b/Documentation/networking/nexthop-group-resilient.rst @@ -0,0 +1,293 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================= +Resilient Next-hop Groups +========================= + +Resilient groups are a type of next-hop group that is aimed at minimizing +disruption in flow routing across changes to the group composition and +weights of constituent next hops. + +The idea behind resilient hashing groups is best explained in contrast to +the legacy multipath next-hop group, which uses the hash-threshold +algorithm, described in RFC 2992. + +To select a next hop, hash-threshold algorithm first assigns a range of +hashes to each next hop in the group, and then selects the next hop by +comparing the SKB hash with the individual ranges. When a next hop is +removed from the group, the ranges are recomputed, which leads to +reassignment of parts of hash space from one next hop to another. RFC 2992 +illustrates it thus:: + + +-------+-------+-------+-------+-------+ + | 1 | 2 | 3 | 4 | 5 | + +-------+-+-----+---+---+-----+-+-------+ + | 1 | 2 | 4 | 5 | + +---------+---------+---------+---------+ + + Before and after deletion of next hop 3 + under the hash-threshold algorithm. + +Note how next hop 2 gave up part of the hash space in favor of next hop 1, +and 4 in favor of 5. While there will usually be some overlap between the +previous and the new distribution, some traffic flows change the next hop +that they resolve to. + +If a multipath group is used for load-balancing between multiple servers, +this hash space reassignment causes an issue that packets from a single +flow suddenly end up arriving at a server that does not expect them. This +can result in TCP connections being reset. + +If a multipath group is used for load-balancing among available paths to +the same server, the issue is that different latencies and reordering along +the way causes the packets to arrive in the wrong order, resulting in +degraded application performance. + +To mitigate the above-mentioned flow redirection, resilient next-hop groups +insert another layer of indirection between the hash space and its +constituent next hops: a hash table. The selection algorithm uses SKB hash +to choose a hash table bucket, then reads the next hop that this bucket +contains, and forwards traffic there. + +This indirection brings an important feature. In the hash-threshold +algorithm, the range of hashes associated with a next hop must be +continuous. With a hash table, mapping between the hash table buckets and +the individual next hops is arbitrary. Therefore when a next hop is deleted +the buckets that held it are simply reassigned to other next hops:: + + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |1|1|1|1|2|2|2|2|3|3|3|3|4|4|4|4|5|5|5|5| + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + v v v v + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |1|1|1|1|2|2|2|2|1|2|4|5|4|4|4|4|5|5|5|5| + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + Before and after deletion of next hop 3 + under the resilient hashing algorithm. + +When weights of next hops in a group are altered, it may be possible to +choose a subset of buckets that are currently not used for forwarding +traffic, and use those to satisfy the new next-hop distribution demands, +keeping the "busy" buckets intact. This way, established flows are ideally +kept being forwarded to the same endpoints through the same paths as before +the next-hop group change. + +Algorithm +--------- + +In a nutshell, the algorithm works as follows. Each next hop deserves a +certain number of buckets, according to its weight and the number of +buckets in the hash table. In accordance with the source code, we will call +this number a "wants count" of a next hop. In case of an event that might +cause bucket allocation change, the wants counts for individual next hops +are updated. + +Next hops that have fewer buckets than their wants count, are called +"underweight". Those that have more are "overweight". If there are no +overweight (and therefore no underweight) next hops in the group, it is +said to be "balanced". + +Each bucket maintains a last-used timer. Every time a packet is forwarded +through a bucket, this timer is updated to current jiffies value. One +attribute of a resilient group is then the "idle timer", which is the +amount of time that a bucket must not be hit by traffic in order for it to +be considered "idle". Buckets that are not idle are busy. + +After assigning wants counts to next hops, an "upkeep" algorithm runs. For +buckets: + +1) that have no assigned next hop, or +2) whose next hop has been removed, or +3) that are idle and their next hop is overweight, + +upkeep changes the next hop that the bucket references to one of the +underweight next hops. If, after considering all buckets in this manner, +there are still underweight next hops, another upkeep run is scheduled to a +future time. + +There may not be enough "idle" buckets to satisfy the updated wants counts +of all next hops. Another attribute of a resilient group is the "unbalanced +timer". This timer can be set to 0, in which case the table will stay out +of balance until idle buckets do appear, possibly never. If set to a +non-zero value, the value represents the period of time that the table is +permitted to stay out of balance. + +With this in mind, we update the above list of conditions with one more +item. Thus buckets: + +4) whose next hop is overweight, and the amount of time that the table has + been out of balance exceeds the unbalanced timer, if that is non-zero, + +\... are migrated as well. + +Offloading & Driver Feedback +---------------------------- + +When offloading resilient groups, the algorithm that distributes buckets +among next hops is still the one in SW. Drivers are notified of updates to +next hop groups in the following three ways: + +- Full group notification with the type + ``NH_NOTIFIER_INFO_TYPE_RES_TABLE``. This is used just after the group is + created and buckets populated for the first time. + +- Single-bucket notifications of the type + ``NH_NOTIFIER_INFO_TYPE_RES_BUCKET``, which is used for notifications of + individual migrations within an already-established group. + +- Pre-replace notification, ``NEXTHOP_EVENT_RES_TABLE_PRE_REPLACE``. This + is sent before the group is replaced, and is a way for the driver to veto + the group before committing anything to the HW. + +Some single-bucket notifications are forced, as indicated by the "force" +flag in the notification. Those are used for the cases where e.g. the next +hop associated with the bucket was removed, and the bucket really must be +migrated. + +Non-forced notifications can be overridden by the driver by returning an +error code. The use case for this is that the driver notifies the HW that a +bucket should be migrated, but the HW discovers that the bucket has in fact +been hit by traffic. + +A second way for the HW to report that a bucket is busy is through the +``nexthop_res_grp_activity_update()`` API. The buckets identified this way +as busy are treated as if traffic hit them. + +Offloaded buckets should be flagged as either "offload" or "trap". This is +done through the ``nexthop_bucket_set_hw_flags()`` API. + +Netlink UAPI +------------ + +Resilient Group Replacement +^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Resilient groups are configured using the ``RTM_NEWNEXTHOP`` message in the +same manner as other multipath groups. The following changes apply to the +attributes passed in the netlink message: + + =================== ========================================================= + ``NHA_GROUP_TYPE`` Should be ``NEXTHOP_GRP_TYPE_RES`` for resilient group. + ``NHA_RES_GROUP`` A nest that contains attributes specific to resilient + groups. + =================== ========================================================= + +``NHA_RES_GROUP`` payload: + + =================================== ========================================= + ``NHA_RES_GROUP_BUCKETS`` Number of buckets in the hash table. + ``NHA_RES_GROUP_IDLE_TIMER`` Idle timer in units of clock_t. + ``NHA_RES_GROUP_UNBALANCED_TIMER`` Unbalanced timer in units of clock_t. + =================================== ========================================= + +Next Hop Get +^^^^^^^^^^^^ + +Requests to get resilient next-hop groups use the ``RTM_GETNEXTHOP`` +message in exactly the same way as other next hop get requests. The +response attributes match the replacement attributes cited above, except +``NHA_RES_GROUP`` payload will include the following attribute: + + =================================== ========================================= + ``NHA_RES_GROUP_UNBALANCED_TIME`` How long has the resilient group been out + of balance, in units of clock_t. + =================================== ========================================= + +Bucket Get +^^^^^^^^^^ + +The message ``RTM_GETNEXTHOPBUCKET`` without the ``NLM_F_DUMP`` flag is +used to request a single bucket. The attributes recognized at get requests +are: + + =================== ========================================================= + ``NHA_ID`` ID of the next-hop group that the bucket belongs to. + ``NHA_RES_BUCKET`` A nest that contains attributes specific to bucket. + =================== ========================================================= + +``NHA_RES_BUCKET`` payload: + + ======================== ==================================================== + ``NHA_RES_BUCKET_INDEX`` Index of bucket in the resilient table. + ======================== ==================================================== + +Bucket Dumps +^^^^^^^^^^^^ + +The message ``RTM_GETNEXTHOPBUCKET`` with the ``NLM_F_DUMP`` flag is used +to request a dump of matching buckets. The attributes recognized at dump +requests are: + + =================== ========================================================= + ``NHA_ID`` If specified, limits the dump to just the next-hop group + with this ID. + ``NHA_OIF`` If specified, limits the dump to buckets that contain + next hops that use the device with this ifindex. + ``NHA_MASTER`` If specified, limits the dump to buckets that contain + next hops that use a device in the VRF with this ifindex. + ``NHA_RES_BUCKET`` A nest that contains attributes specific to bucket. + =================== ========================================================= + +``NHA_RES_BUCKET`` payload: + + ======================== ==================================================== + ``NHA_RES_BUCKET_NH_ID`` If specified, limits the dump to just the buckets + that contain the next hop with this ID. + ======================== ==================================================== + +Usage +----- + +To illustrate the usage, consider the following commands:: + + # ip nexthop add id 1 via 192.0.2.2 dev eth0 + # ip nexthop add id 2 via 192.0.2.3 dev eth0 + # ip nexthop add id 10 group 1/2 type resilient \ + buckets 8 idle_timer 60 unbalanced_timer 300 + +The last command creates a resilient next-hop group. It will have 8 buckets +(which is unusually low number, and used here for demonstration purposes +only), each bucket will be considered idle when no traffic hits it for at +least 60 seconds, and if the table remains out of balance for 300 seconds, +it will be forcefully brought into balance. + +Changing next-hop weights leads to change in bucket allocation:: + + # ip nexthop replace id 10 group 1,3/2 type resilient + +This can be confirmed by looking at individual buckets:: + + # ip nexthop bucket show id 10 + id 10 index 0 idle_time 5.59 nhid 1 + id 10 index 1 idle_time 5.59 nhid 1 + id 10 index 2 idle_time 8.74 nhid 2 + id 10 index 3 idle_time 8.74 nhid 2 + id 10 index 4 idle_time 8.74 nhid 1 + id 10 index 5 idle_time 8.74 nhid 1 + id 10 index 6 idle_time 8.74 nhid 1 + id 10 index 7 idle_time 8.74 nhid 1 + +Note the two buckets that have a shorter idle time. Those are the ones that +were migrated after the next-hop replace command to satisfy the new demand +that next hop 1 be given 6 buckets instead of 4. + +Netdevsim +--------- + +The netdevsim driver implements a mock offload of resilient groups, and +exposes debugfs interface that allows marking individual buckets as busy. +For example, the following will mark bucket 23 in next-hop group 10 as +active:: + + # echo 10 23 > /sys/kernel/debug/netdevsim/netdevsim10/fib/nexthop_bucket_activity + +In addition, another debugfs interface can be used to configure that the +next attempt to migrate a bucket should fail:: + + # echo 1 > /sys/kernel/debug/netdevsim/netdevsim10/fib/fail_nexthop_bucket_replace + +Besides serving as an example, the interfaces that netdevsim exposes are +useful in automated testing, and +``tools/testing/selftests/drivers/net/netdevsim/nexthop.sh`` makes use of +them to test the algorithm. diff --git a/Documentation/networking/nf_conntrack-sysctl.rst b/Documentation/networking/nf_conntrack-sysctl.rst new file mode 100644 index 0000000000..c383a394c6 --- /dev/null +++ b/Documentation/networking/nf_conntrack-sysctl.rst @@ -0,0 +1,232 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=================================== +Netfilter Conntrack Sysfs variables +=================================== + +/proc/sys/net/netfilter/nf_conntrack_* Variables: +================================================= + +nf_conntrack_acct - BOOLEAN + - 0 - disabled (default) + - not 0 - enabled + + Enable connection tracking flow accounting. 64-bit byte and packet + counters per flow are added. + +nf_conntrack_buckets - INTEGER + Size of hash table. If not specified as parameter during module + loading, the default size is calculated by dividing total memory + by 16384 to determine the number of buckets. The hash table will + never have fewer than 1024 and never more than 262144 buckets. + This sysctl is only writeable in the initial net namespace. + +nf_conntrack_checksum - BOOLEAN + - 0 - disabled + - not 0 - enabled (default) + + Verify checksum of incoming packets. Packets with bad checksums are + in INVALID state. If this is enabled, such packets will not be + considered for connection tracking. + +nf_conntrack_count - INTEGER (read-only) + Number of currently allocated flow entries. + +nf_conntrack_events - BOOLEAN + - 0 - disabled + - 1 - enabled + - 2 - auto (default) + + If this option is enabled, the connection tracking code will + provide userspace with connection tracking events via ctnetlink. + The default allocates the extension if a userspace program is + listening to ctnetlink events. + +nf_conntrack_expect_max - INTEGER + Maximum size of expectation table. Default value is + nf_conntrack_buckets / 256. Minimum is 1. + +nf_conntrack_frag6_high_thresh - INTEGER + default 262144 + + Maximum memory used to reassemble IPv6 fragments. When + nf_conntrack_frag6_high_thresh bytes of memory is allocated for this + purpose, the fragment handler will toss packets until + nf_conntrack_frag6_low_thresh is reached. + +nf_conntrack_frag6_low_thresh - INTEGER + default 196608 + + See nf_conntrack_frag6_low_thresh + +nf_conntrack_frag6_timeout - INTEGER (seconds) + default 60 + + Time to keep an IPv6 fragment in memory. + +nf_conntrack_generic_timeout - INTEGER (seconds) + default 600 + + Default for generic timeout. This refers to layer 4 unknown/unsupported + protocols. + +nf_conntrack_icmp_timeout - INTEGER (seconds) + default 30 + + Default for ICMP timeout. + +nf_conntrack_icmpv6_timeout - INTEGER (seconds) + default 30 + + Default for ICMP6 timeout. + +nf_conntrack_log_invalid - INTEGER + - 0 - disable (default) + - 1 - log ICMP packets + - 6 - log TCP packets + - 17 - log UDP packets + - 33 - log DCCP packets + - 41 - log ICMPv6 packets + - 136 - log UDPLITE packets + - 255 - log packets of any protocol + + Log invalid packets of a type specified by value. + +nf_conntrack_max - INTEGER + Maximum number of allowed connection tracking entries. This value is set + to nf_conntrack_buckets by default. + Note that connection tracking entries are added to the table twice -- once + for the original direction and once for the reply direction (i.e., with + the reversed address). This means that with default settings a maxed-out + table will have a average hash chain length of 2, not 1. + +nf_conntrack_tcp_be_liberal - BOOLEAN + - 0 - disabled (default) + - not 0 - enabled + + Be conservative in what you do, be liberal in what you accept from others. + If it's non-zero, we mark only out of window RST segments as INVALID. + +nf_conntrack_tcp_ignore_invalid_rst - BOOLEAN + - 0 - disabled (default) + - 1 - enabled + + If it's 1, we don't mark out of window RST segments as INVALID. + +nf_conntrack_tcp_loose - BOOLEAN + - 0 - disabled + - not 0 - enabled (default) + + If it is set to zero, we disable picking up already established + connections. + +nf_conntrack_tcp_max_retrans - INTEGER + default 3 + + Maximum number of packets that can be retransmitted without + received an (acceptable) ACK from the destination. If this number + is reached, a shorter timer will be started. + +nf_conntrack_tcp_timeout_close - INTEGER (seconds) + default 10 + +nf_conntrack_tcp_timeout_close_wait - INTEGER (seconds) + default 60 + +nf_conntrack_tcp_timeout_established - INTEGER (seconds) + default 432000 (5 days) + +nf_conntrack_tcp_timeout_fin_wait - INTEGER (seconds) + default 120 + +nf_conntrack_tcp_timeout_last_ack - INTEGER (seconds) + default 30 + +nf_conntrack_tcp_timeout_max_retrans - INTEGER (seconds) + default 300 + +nf_conntrack_tcp_timeout_syn_recv - INTEGER (seconds) + default 60 + +nf_conntrack_tcp_timeout_syn_sent - INTEGER (seconds) + default 120 + +nf_conntrack_tcp_timeout_time_wait - INTEGER (seconds) + default 120 + +nf_conntrack_tcp_timeout_unacknowledged - INTEGER (seconds) + default 300 + +nf_conntrack_timestamp - BOOLEAN + - 0 - disabled (default) + - not 0 - enabled + + Enable connection tracking flow timestamping. + +nf_conntrack_sctp_timeout_closed - INTEGER (seconds) + default 10 + +nf_conntrack_sctp_timeout_cookie_wait - INTEGER (seconds) + default 3 + +nf_conntrack_sctp_timeout_cookie_echoed - INTEGER (seconds) + default 3 + +nf_conntrack_sctp_timeout_established - INTEGER (seconds) + default 210 + + Default is set to (hb_interval * path_max_retrans + rto_max) + +nf_conntrack_sctp_timeout_shutdown_sent - INTEGER (seconds) + default 3 + +nf_conntrack_sctp_timeout_shutdown_recd - INTEGER (seconds) + default 3 + +nf_conntrack_sctp_timeout_shutdown_ack_sent - INTEGER (seconds) + default 3 + +nf_conntrack_sctp_timeout_heartbeat_sent - INTEGER (seconds) + default 30 + + This timeout is used to setup conntrack entry on secondary paths. + Default is set to hb_interval. + +nf_conntrack_udp_timeout - INTEGER (seconds) + default 30 + +nf_conntrack_udp_timeout_stream - INTEGER (seconds) + default 120 + + This extended timeout will be used in case there is an UDP stream + detected. + +nf_conntrack_gre_timeout - INTEGER (seconds) + default 30 + +nf_conntrack_gre_timeout_stream - INTEGER (seconds) + default 180 + + This extended timeout will be used in case there is an GRE stream + detected. + +nf_hooks_lwtunnel - BOOLEAN + - 0 - disabled (default) + - not 0 - enabled + + If this option is enabled, the lightweight tunnel netfilter hooks are + enabled. This option cannot be disabled once it is enabled. + +nf_flowtable_tcp_timeout - INTEGER (seconds) + default 30 + + Control offload timeout for tcp connections. + TCP connections may be offloaded from nf conntrack to nf flow table. + Once aged, the connection is returned to nf conntrack with tcp pickup timeout. + +nf_flowtable_udp_timeout - INTEGER (seconds) + default 30 + + Control offload timeout for udp connections. + UDP connections may be offloaded from nf conntrack to nf flow table. + Once aged, the connection is returned to nf conntrack with udp pickup timeout. diff --git a/Documentation/networking/nf_flowtable.rst b/Documentation/networking/nf_flowtable.rst new file mode 100644 index 0000000000..d757c21c10 --- /dev/null +++ b/Documentation/networking/nf_flowtable.rst @@ -0,0 +1,235 @@ +.. SPDX-License-Identifier: GPL-2.0 + +==================================== +Netfilter's flowtable infrastructure +==================================== + +This documentation describes the Netfilter flowtable infrastructure which allows +you to define a fastpath through the flowtable datapath. This infrastructure +also provides hardware offload support. The flowtable supports for the layer 3 +IPv4 and IPv6 and the layer 4 TCP and UDP protocols. + +Overview +-------- + +Once the first packet of the flow successfully goes through the IP forwarding +path, from the second packet on, you might decide to offload the flow to the +flowtable through your ruleset. The flowtable infrastructure provides a rule +action that allows you to specify when to add a flow to the flowtable. + +A packet that finds a matching entry in the flowtable (ie. flowtable hit) is +transmitted to the output netdevice via neigh_xmit(), hence, packets bypass the +classic IP forwarding path (the visible effect is that you do not see these +packets from any of the Netfilter hooks coming after ingress). In case that +there is no matching entry in the flowtable (ie. flowtable miss), the packet +follows the classic IP forwarding path. + +The flowtable uses a resizable hashtable. Lookups are based on the following +n-tuple selectors: layer 2 protocol encapsulation (VLAN and PPPoE), layer 3 +source and destination, layer 4 source and destination ports and the input +interface (useful in case there are several conntrack zones in place). + +The 'flow add' action allows you to populate the flowtable, the user selectively +specifies what flows are placed into the flowtable. Hence, packets follow the +classic IP forwarding path unless the user explicitly instruct flows to use this +new alternative forwarding path via policy. + +The flowtable datapath is represented in Fig.1, which describes the classic IP +forwarding path including the Netfilter hooks and the flowtable fastpath bypass. + +:: + + userspace process + ^ | + | | + _____|____ ____\/___ + / \ / \ + | input | | output | + \__________/ \_________/ + ^ | + | | + _________ __________ --------- _____\/_____ + / \ / \ |Routing | / \ + --> ingress ---> prerouting ---> |decision| | postrouting |--> neigh_xmit + \_________/ \__________/ ---------- \____________/ ^ + | ^ | ^ | + flowtable | ____\/___ | | + | | / \ | | + __\/___ | | forward |------------ | + |-----| | \_________/ | + |-----| | 'flow offload' rule | + |-----| | adds entry to | + |_____| | flowtable | + | | | + / \ | | + /hit\_no_| | + \ ? / | + \ / | + |__yes_________________fastpath bypass ____________________________| + + Fig.1 Netfilter hooks and flowtable interactions + +The flowtable entry also stores the NAT configuration, so all packets are +mangled according to the NAT policy that is specified from the classic IP +forwarding path. The TTL is decremented before calling neigh_xmit(). Fragmented +traffic is passed up to follow the classic IP forwarding path given that the +transport header is missing, in this case, flowtable lookups are not possible. +TCP RST and FIN packets are also passed up to the classic IP forwarding path to +release the flow gracefully. Packets that exceed the MTU are also passed up to +the classic forwarding path to report packet-too-big ICMP errors to the sender. + +Example configuration +--------------------- + +Enabling the flowtable bypass is relatively easy, you only need to create a +flowtable and add one rule to your forward chain:: + + table inet x { + flowtable f { + hook ingress priority 0; devices = { eth0, eth1 }; + } + chain y { + type filter hook forward priority 0; policy accept; + ip protocol tcp flow add @f + counter packets 0 bytes 0 + } + } + +This example adds the flowtable 'f' to the ingress hook of the eth0 and eth1 +netdevices. You can create as many flowtables as you want in case you need to +perform resource partitioning. The flowtable priority defines the order in which +hooks are run in the pipeline, this is convenient in case you already have a +nftables ingress chain (make sure the flowtable priority is smaller than the +nftables ingress chain hence the flowtable runs before in the pipeline). + +The 'flow offload' action from the forward chain 'y' adds an entry to the +flowtable for the TCP syn-ack packet coming in the reply direction. Once the +flow is offloaded, you will observe that the counter rule in the example above +does not get updated for the packets that are being forwarded through the +forwarding bypass. + +You can identify offloaded flows through the [OFFLOAD] tag when listing your +connection tracking table. + +:: + + # conntrack -L + tcp 6 src=10.141.10.2 dst=192.168.10.2 sport=52728 dport=5201 src=192.168.10.2 dst=192.168.10.1 sport=5201 dport=52728 [OFFLOAD] mark=0 use=2 + + +Layer 2 encapsulation +--------------------- + +Since Linux kernel 5.13, the flowtable infrastructure discovers the real +netdevice behind VLAN and PPPoE netdevices. The flowtable software datapath +parses the VLAN and PPPoE layer 2 headers to extract the ethertype and the +VLAN ID / PPPoE session ID which are used for the flowtable lookups. The +flowtable datapath also deals with layer 2 decapsulation. + +You do not need to add the PPPoE and the VLAN devices to your flowtable, +instead the real device is sufficient for the flowtable to track your flows. + +Bridge and IP forwarding +------------------------ + +Since Linux kernel 5.13, you can add bridge ports to the flowtable. The +flowtable infrastructure discovers the topology behind the bridge device. This +allows the flowtable to define a fastpath bypass between the bridge ports +(represented as eth1 and eth2 in the example figure below) and the gateway +device (represented as eth0) in your switch/router. + +:: + + fastpath bypass + .-------------------------. + / \ + | IP forwarding | + | / \ \/ + | br0 eth0 ..... eth0 + . / \ *host B* + -> eth1 eth2 + . *switch/router* + . + . + eth0 + *host A* + +The flowtable infrastructure also supports for bridge VLAN filtering actions +such as PVID and untagged. You can also stack a classic VLAN device on top of +your bridge port. + +If you would like that your flowtable defines a fastpath between your bridge +ports and your IP forwarding path, you have to add your bridge ports (as +represented by the real netdevice) to your flowtable definition. + +Counters +-------- + +The flowtable can synchronize packet and byte counters with the existing +connection tracking entry by specifying the counter statement in your flowtable +definition, e.g. + +:: + + table inet x { + flowtable f { + hook ingress priority 0; devices = { eth0, eth1 }; + counter + } + } + +Counter support is available since Linux kernel 5.7. + +Hardware offload +---------------- + +If your network device provides hardware offload support, you can turn it on by +means of the 'offload' flag in your flowtable definition, e.g. + +:: + + table inet x { + flowtable f { + hook ingress priority 0; devices = { eth0, eth1 }; + flags offload; + } + } + +There is a workqueue that adds the flows to the hardware. Note that a few +packets might still run over the flowtable software path until the workqueue has +a chance to offload the flow to the network device. + +You can identify hardware offloaded flows through the [HW_OFFLOAD] tag when +listing your connection tracking table. Please, note that the [OFFLOAD] tag +refers to the software offload mode, so there is a distinction between [OFFLOAD] +which refers to the software flowtable fastpath and [HW_OFFLOAD] which refers +to the hardware offload datapath being used by the flow. + +The flowtable hardware offload infrastructure also supports for the DSA +(Distributed Switch Architecture). + +Limitations +----------- + +The flowtable behaves like a cache. The flowtable entries might get stale if +either the destination MAC address or the egress netdevice that is used for +transmission changes. + +This might be a problem if: + +- You run the flowtable in software mode and you combine bridge and IP + forwarding in your setup. +- Hardware offload is enabled. + +More reading +------------ + +This documentation is based on the LWN.net articles [1]_\ [2]_. Rafal Milecki +also made a very complete and comprehensive summary called "A state of network +acceleration" that describes how things were before this infrastructure was +mainlined [3]_ and it also makes a rough summary of this work [4]_. + +.. [1] https://lwn.net/Articles/738214/ +.. [2] https://lwn.net/Articles/742164/ +.. [3] http://lists.infradead.org/pipermail/lede-dev/2018-January/010830.html +.. [4] http://lists.infradead.org/pipermail/lede-dev/2018-January/010829.html diff --git a/Documentation/networking/nfc.rst b/Documentation/networking/nfc.rst new file mode 100644 index 0000000000..9aab3a88c9 --- /dev/null +++ b/Documentation/networking/nfc.rst @@ -0,0 +1,130 @@ +=================== +Linux NFC subsystem +=================== + +The Near Field Communication (NFC) subsystem is required to standardize the +NFC device drivers development and to create an unified userspace interface. + +This document covers the architecture overview, the device driver interface +description and the userspace interface description. + +Architecture overview +===================== + +The NFC subsystem is responsible for: + - NFC adapters management; + - Polling for targets; + - Low-level data exchange; + +The subsystem is divided in some parts. The 'core' is responsible for +providing the device driver interface. On the other side, it is also +responsible for providing an interface to control operations and low-level +data exchange. + +The control operations are available to userspace via generic netlink. + +The low-level data exchange interface is provided by the new socket family +PF_NFC. The NFC_SOCKPROTO_RAW performs raw communication with NFC targets. + +.. code-block:: none + + +--------------------------------------+ + | USER SPACE | + +--------------------------------------+ + ^ ^ + | low-level | control + | data exchange | operations + | | + | v + | +-----------+ + | AF_NFC | netlink | + | socket +-----------+ + | raw ^ + | | + v v + +---------+ +-----------+ + | rawsock | <--------> | core | + +---------+ +-----------+ + ^ + | + v + +-----------+ + | driver | + +-----------+ + +Device Driver Interface +======================= + +When registering on the NFC subsystem, the device driver must inform the core +of the set of supported NFC protocols and the set of ops callbacks. The ops +callbacks that must be implemented are the following: + +* start_poll - setup the device to poll for targets +* stop_poll - stop on progress polling operation +* activate_target - select and initialize one of the targets found +* deactivate_target - deselect and deinitialize the selected target +* data_exchange - send data and receive the response (transceive operation) + +Userspace interface +=================== + +The userspace interface is divided in control operations and low-level data +exchange operation. + +CONTROL OPERATIONS: + +Generic netlink is used to implement the interface to the control operations. +The operations are composed by commands and events, all listed below: + +* NFC_CMD_GET_DEVICE - get specific device info or dump the device list +* NFC_CMD_START_POLL - setup a specific device to polling for targets +* NFC_CMD_STOP_POLL - stop the polling operation in a specific device +* NFC_CMD_GET_TARGET - dump the list of targets found by a specific device + +* NFC_EVENT_DEVICE_ADDED - reports an NFC device addition +* NFC_EVENT_DEVICE_REMOVED - reports an NFC device removal +* NFC_EVENT_TARGETS_FOUND - reports START_POLL results when 1 or more targets + are found + +The user must call START_POLL to poll for NFC targets, passing the desired NFC +protocols through NFC_ATTR_PROTOCOLS attribute. The device remains in polling +state until it finds any target. However, the user can stop the polling +operation by calling STOP_POLL command. In this case, it will be checked if +the requester of STOP_POLL is the same of START_POLL. + +If the polling operation finds one or more targets, the event TARGETS_FOUND is +sent (including the device id). The user must call GET_TARGET to get the list of +all targets found by such device. Each reply message has target attributes with +relevant information such as the supported NFC protocols. + +All polling operations requested through one netlink socket are stopped when +it's closed. + +LOW-LEVEL DATA EXCHANGE: + +The userspace must use PF_NFC sockets to perform any data communication with +targets. All NFC sockets use AF_NFC:: + + struct sockaddr_nfc { + sa_family_t sa_family; + __u32 dev_idx; + __u32 target_idx; + __u32 nfc_protocol; + }; + +To establish a connection with one target, the user must create an +NFC_SOCKPROTO_RAW socket and call the 'connect' syscall with the sockaddr_nfc +struct correctly filled. All information comes from NFC_EVENT_TARGETS_FOUND +netlink event. As a target can support more than one NFC protocol, the user +must inform which protocol it wants to use. + +Internally, 'connect' will result in an activate_target call to the driver. +When the socket is closed, the target is deactivated. + +The data format exchanged through the sockets is NFC protocol dependent. For +instance, when communicating with MIFARE tags, the data exchanged are MIFARE +commands and their responses. + +The first received package is the response to the first sent package and so +on. In order to allow valid "empty" responses, every data received has a NULL +header of 1 byte. diff --git a/Documentation/networking/openvswitch.rst b/Documentation/networking/openvswitch.rst new file mode 100644 index 0000000000..1a8353dbf1 --- /dev/null +++ b/Documentation/networking/openvswitch.rst @@ -0,0 +1,251 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================================= +Open vSwitch datapath developer documentation +============================================= + +The Open vSwitch kernel module allows flexible userspace control over +flow-level packet processing on selected network devices. It can be +used to implement a plain Ethernet switch, network device bonding, +VLAN processing, network access control, flow-based network control, +and so on. + +The kernel module implements multiple "datapaths" (analogous to +bridges), each of which can have multiple "vports" (analogous to ports +within a bridge). Each datapath also has associated with it a "flow +table" that userspace populates with "flows" that map from keys based +on packet headers and metadata to sets of actions. The most common +action forwards the packet to another vport; other actions are also +implemented. + +When a packet arrives on a vport, the kernel module processes it by +extracting its flow key and looking it up in the flow table. If there +is a matching flow, it executes the associated actions. If there is +no match, it queues the packet to userspace for processing (as part of +its processing, userspace will likely set up a flow to handle further +packets of the same type entirely in-kernel). + + +Flow key compatibility +---------------------- + +Network protocols evolve over time. New protocols become important +and existing protocols lose their prominence. For the Open vSwitch +kernel module to remain relevant, it must be possible for newer +versions to parse additional protocols as part of the flow key. It +might even be desirable, someday, to drop support for parsing +protocols that have become obsolete. Therefore, the Netlink interface +to Open vSwitch is designed to allow carefully written userspace +applications to work with any version of the flow key, past or future. + +To support this forward and backward compatibility, whenever the +kernel module passes a packet to userspace, it also passes along the +flow key that it parsed from the packet. Userspace then extracts its +own notion of a flow key from the packet and compares it against the +kernel-provided version: + + - If userspace's notion of the flow key for the packet matches the + kernel's, then nothing special is necessary. + + - If the kernel's flow key includes more fields than the userspace + version of the flow key, for example if the kernel decoded IPv6 + headers but userspace stopped at the Ethernet type (because it + does not understand IPv6), then again nothing special is + necessary. Userspace can still set up a flow in the usual way, + as long as it uses the kernel-provided flow key to do it. + + - If the userspace flow key includes more fields than the + kernel's, for example if userspace decoded an IPv6 header but + the kernel stopped at the Ethernet type, then userspace can + forward the packet manually, without setting up a flow in the + kernel. This case is bad for performance because every packet + that the kernel considers part of the flow must go to userspace, + but the forwarding behavior is correct. (If userspace can + determine that the values of the extra fields would not affect + forwarding behavior, then it could set up a flow anyway.) + +How flow keys evolve over time is important to making this work, so +the following sections go into detail. + + +Flow key format +--------------- + +A flow key is passed over a Netlink socket as a sequence of Netlink +attributes. Some attributes represent packet metadata, defined as any +information about a packet that cannot be extracted from the packet +itself, e.g. the vport on which the packet was received. Most +attributes, however, are extracted from headers within the packet, +e.g. source and destination addresses from Ethernet, IP, or TCP +headers. + +The <linux/openvswitch.h> header file defines the exact format of the +flow key attributes. For informal explanatory purposes here, we write +them as comma-separated strings, with parentheses indicating arguments +and nesting. For example, the following could represent a flow key +corresponding to a TCP packet that arrived on vport 1:: + + in_port(1), eth(src=e0:91:f5:21:d0:b2, dst=00:02:e3:0f:80:a4), + eth_type(0x0800), ipv4(src=172.16.0.20, dst=172.18.0.52, proto=17, tos=0, + frag=no), tcp(src=49163, dst=80) + +Often we ellipsize arguments not important to the discussion, e.g.:: + + in_port(1), eth(...), eth_type(0x0800), ipv4(...), tcp(...) + + +Wildcarded flow key format +-------------------------- + +A wildcarded flow is described with two sequences of Netlink attributes +passed over the Netlink socket. A flow key, exactly as described above, and an +optional corresponding flow mask. + +A wildcarded flow can represent a group of exact match flows. Each '1' bit +in the mask specifies a exact match with the corresponding bit in the flow key. +A '0' bit specifies a don't care bit, which will match either a '1' or '0' bit +of a incoming packet. Using wildcarded flow can improve the flow set up rate +by reduce the number of new flows need to be processed by the user space program. + +Support for the mask Netlink attribute is optional for both the kernel and user +space program. The kernel can ignore the mask attribute, installing an exact +match flow, or reduce the number of don't care bits in the kernel to less than +what was specified by the user space program. In this case, variations in bits +that the kernel does not implement will simply result in additional flow setups. +The kernel module will also work with user space programs that neither support +nor supply flow mask attributes. + +Since the kernel may ignore or modify wildcard bits, it can be difficult for +the userspace program to know exactly what matches are installed. There are +two possible approaches: reactively install flows as they miss the kernel +flow table (and therefore not attempt to determine wildcard changes at all) +or use the kernel's response messages to determine the installed wildcards. + +When interacting with userspace, the kernel should maintain the match portion +of the key exactly as originally installed. This will provides a handle to +identify the flow for all future operations. However, when reporting the +mask of an installed flow, the mask should include any restrictions imposed +by the kernel. + +The behavior when using overlapping wildcarded flows is undefined. It is the +responsibility of the user space program to ensure that any incoming packet +can match at most one flow, wildcarded or not. The current implementation +performs best-effort detection of overlapping wildcarded flows and may reject +some but not all of them. However, this behavior may change in future versions. + + +Unique flow identifiers +----------------------- + +An alternative to using the original match portion of a key as the handle for +flow identification is a unique flow identifier, or "UFID". UFIDs are optional +for both the kernel and user space program. + +User space programs that support UFID are expected to provide it during flow +setup in addition to the flow, then refer to the flow using the UFID for all +future operations. The kernel is not required to index flows by the original +flow key if a UFID is specified. + + +Basic rule for evolving flow keys +--------------------------------- + +Some care is needed to really maintain forward and backward +compatibility for applications that follow the rules listed under +"Flow key compatibility" above. + +The basic rule is obvious:: + + ================================================================== + New network protocol support must only supplement existing flow + key attributes. It must not change the meaning of already defined + flow key attributes. + ================================================================== + +This rule does have less-obvious consequences so it is worth working +through a few examples. Suppose, for example, that the kernel module +did not already implement VLAN parsing. Instead, it just interpreted +the 802.1Q TPID (0x8100) as the Ethertype then stopped parsing the +packet. The flow key for any packet with an 802.1Q header would look +essentially like this, ignoring metadata:: + + eth(...), eth_type(0x8100) + +Naively, to add VLAN support, it makes sense to add a new "vlan" flow +key attribute to contain the VLAN tag, then continue to decode the +encapsulated headers beyond the VLAN tag using the existing field +definitions. With this change, a TCP packet in VLAN 10 would have a +flow key much like this:: + + eth(...), vlan(vid=10, pcp=0), eth_type(0x0800), ip(proto=6, ...), tcp(...) + +But this change would negatively affect a userspace application that +has not been updated to understand the new "vlan" flow key attribute. +The application could, following the flow compatibility rules above, +ignore the "vlan" attribute that it does not understand and therefore +assume that the flow contained IP packets. This is a bad assumption +(the flow only contains IP packets if one parses and skips over the +802.1Q header) and it could cause the application's behavior to change +across kernel versions even though it follows the compatibility rules. + +The solution is to use a set of nested attributes. This is, for +example, why 802.1Q support uses nested attributes. A TCP packet in +VLAN 10 is actually expressed as:: + + eth(...), eth_type(0x8100), vlan(vid=10, pcp=0), encap(eth_type(0x0800), + ip(proto=6, ...), tcp(...))) + +Notice how the "eth_type", "ip", and "tcp" flow key attributes are +nested inside the "encap" attribute. Thus, an application that does +not understand the "vlan" key will not see either of those attributes +and therefore will not misinterpret them. (Also, the outer eth_type +is still 0x8100, not changed to 0x0800.) + +Handling malformed packets +-------------------------- + +Don't drop packets in the kernel for malformed protocol headers, bad +checksums, etc. This would prevent userspace from implementing a +simple Ethernet switch that forwards every packet. + +Instead, in such a case, include an attribute with "empty" content. +It doesn't matter if the empty content could be valid protocol values, +as long as those values are rarely seen in practice, because userspace +can always forward all packets with those values to userspace and +handle them individually. + +For example, consider a packet that contains an IP header that +indicates protocol 6 for TCP, but which is truncated just after the IP +header, so that the TCP header is missing. The flow key for this +packet would include a tcp attribute with all-zero src and dst, like +this:: + + eth(...), eth_type(0x0800), ip(proto=6, ...), tcp(src=0, dst=0) + +As another example, consider a packet with an Ethernet type of 0x8100, +indicating that a VLAN TCI should follow, but which is truncated just +after the Ethernet type. The flow key for this packet would include +an all-zero-bits vlan and an empty encap attribute, like this:: + + eth(...), eth_type(0x8100), vlan(0), encap() + +Unlike a TCP packet with source and destination ports 0, an +all-zero-bits VLAN TCI is not that rare, so the CFI bit (aka +VLAN_TAG_PRESENT inside the kernel) is ordinarily set in a vlan +attribute expressly to allow this situation to be distinguished. +Thus, the flow key in this second example unambiguously indicates a +missing or malformed VLAN TCI. + +Other rules +----------- + +The other rules for flow keys are much less subtle: + + - Duplicate attributes are not allowed at a given nesting level. + + - Ordering of attributes is not significant. + + - When the kernel sends a given flow key to userspace, it always + composes it the same way. This allows userspace to hash and + compare entire flow keys that it may not be able to fully + interpret. diff --git a/Documentation/networking/operstates.rst b/Documentation/networking/operstates.rst new file mode 100644 index 0000000000..1ee2141e8e --- /dev/null +++ b/Documentation/networking/operstates.rst @@ -0,0 +1,187 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================== +Operational States +================== + + +1. Introduction +=============== + +Linux distinguishes between administrative and operational state of an +interface. Administrative state is the result of "ip link set dev +<dev> up or down" and reflects whether the administrator wants to use +the device for traffic. + +However, an interface is not usable just because the admin enabled it +- ethernet requires to be plugged into the switch and, depending on +a site's networking policy and configuration, an 802.1X authentication +to be performed before user data can be transferred. Operational state +shows the ability of an interface to transmit this user data. + +Thanks to 802.1X, userspace must be granted the possibility to +influence operational state. To accommodate this, operational state is +split into two parts: Two flags that can be set by the driver only, and +a RFC2863 compatible state that is derived from these flags, a policy, +and changeable from userspace under certain rules. + + +2. Querying from userspace +========================== + +Both admin and operational state can be queried via the netlink +operation RTM_GETLINK. It is also possible to subscribe to RTNLGRP_LINK +to be notified of updates while the interface is admin up. This is +important for setting from userspace. + +These values contain interface state: + +ifinfomsg::if_flags & IFF_UP: + Interface is admin up + +ifinfomsg::if_flags & IFF_RUNNING: + Interface is in RFC2863 operational state UP or UNKNOWN. This is for + backward compatibility, routing daemons, dhcp clients can use this + flag to determine whether they should use the interface. + +ifinfomsg::if_flags & IFF_LOWER_UP: + Driver has signaled netif_carrier_on() + +ifinfomsg::if_flags & IFF_DORMANT: + Driver has signaled netif_dormant_on() + +TLV IFLA_OPERSTATE +------------------ + +contains RFC2863 state of the interface in numeric representation: + +IF_OPER_UNKNOWN (0): + Interface is in unknown state, neither driver nor userspace has set + operational state. Interface must be considered for user data as + setting operational state has not been implemented in every driver. + +IF_OPER_NOTPRESENT (1): + Unused in current kernel (notpresent interfaces normally disappear), + just a numerical placeholder. + +IF_OPER_DOWN (2): + Interface is unable to transfer data on L1, f.e. ethernet is not + plugged or interface is ADMIN down. + +IF_OPER_LOWERLAYERDOWN (3): + Interfaces stacked on an interface that is IF_OPER_DOWN show this + state (f.e. VLAN). + +IF_OPER_TESTING (4): + Interface is in testing mode, for example executing driver self-tests + or media (cable) test. It can't be used for normal traffic until tests + complete. + +IF_OPER_DORMANT (5): + Interface is L1 up, but waiting for an external event, f.e. for a + protocol to establish. (802.1X) + +IF_OPER_UP (6): + Interface is operational up and can be used. + +This TLV can also be queried via sysfs. + +TLV IFLA_LINKMODE +----------------- + +contains link policy. This is needed for userspace interaction +described below. + +This TLV can also be queried via sysfs. + + +3. Kernel driver API +==================== + +Kernel drivers have access to two flags that map to IFF_LOWER_UP and +IFF_DORMANT. These flags can be set from everywhere, even from +interrupts. It is guaranteed that only the driver has write access, +however, if different layers of the driver manipulate the same flag, +the driver has to provide the synchronisation needed. + +__LINK_STATE_NOCARRIER, maps to !IFF_LOWER_UP: + +The driver uses netif_carrier_on() to clear and netif_carrier_off() to +set this flag. On netif_carrier_off(), the scheduler stops sending +packets. The name 'carrier' and the inversion are historical, think of +it as lower layer. + +Note that for certain kind of soft-devices, which are not managing any +real hardware, it is possible to set this bit from userspace. One +should use TLV IFLA_CARRIER to do so. + +netif_carrier_ok() can be used to query that bit. + +__LINK_STATE_DORMANT, maps to IFF_DORMANT: + +Set by the driver to express that the device cannot yet be used +because some driver controlled protocol establishment has to +complete. Corresponding functions are netif_dormant_on() to set the +flag, netif_dormant_off() to clear it and netif_dormant() to query. + +On device allocation, both flags __LINK_STATE_NOCARRIER and +__LINK_STATE_DORMANT are cleared, so the effective state is equivalent +to netif_carrier_ok() and !netif_dormant(). + + +Whenever the driver CHANGES one of these flags, a workqueue event is +scheduled to translate the flag combination to IFLA_OPERSTATE as +follows: + +!netif_carrier_ok(): + IF_OPER_LOWERLAYERDOWN if the interface is stacked, IF_OPER_DOWN + otherwise. Kernel can recognise stacked interfaces because their + ifindex != iflink. + +netif_carrier_ok() && netif_dormant(): + IF_OPER_DORMANT + +netif_carrier_ok() && !netif_dormant(): + IF_OPER_UP if userspace interaction is disabled. Otherwise + IF_OPER_DORMANT with the possibility for userspace to initiate the + IF_OPER_UP transition afterwards. + + +4. Setting from userspace +========================= + +Applications have to use the netlink interface to influence the +RFC2863 operational state of an interface. Setting IFLA_LINKMODE to 1 +via RTM_SETLINK instructs the kernel that an interface should go to +IF_OPER_DORMANT instead of IF_OPER_UP when the combination +netif_carrier_ok() && !netif_dormant() is set by the +driver. Afterwards, the userspace application can set IFLA_OPERSTATE +to IF_OPER_DORMANT or IF_OPER_UP as long as the driver does not set +netif_carrier_off() or netif_dormant_on(). Changes made by userspace +are multicasted on the netlink group RTNLGRP_LINK. + +So basically a 802.1X supplicant interacts with the kernel like this: + +- subscribe to RTNLGRP_LINK +- set IFLA_LINKMODE to 1 via RTM_SETLINK +- query RTM_GETLINK once to get initial state +- if initial flags are not (IFF_LOWER_UP && !IFF_DORMANT), wait until + netlink multicast signals this state +- do 802.1X, eventually abort if flags go down again +- send RTM_SETLINK to set operstate to IF_OPER_UP if authentication + succeeds, IF_OPER_DORMANT otherwise +- see how operstate and IFF_RUNNING is echoed via netlink multicast +- set interface back to IF_OPER_DORMANT if 802.1X reauthentication + fails +- restart if kernel changes IFF_LOWER_UP or IFF_DORMANT flag + +if supplicant goes down, bring back IFLA_LINKMODE to 0 and +IFLA_OPERSTATE to a sane value. + +A routing daemon or dhcp client just needs to care for IFF_RUNNING or +waiting for operstate to go IF_OPER_UP/IF_OPER_UNKNOWN before +considering the interface / querying a DHCP address. + + +For technical questions and/or comments please e-mail to Stefan Rompf +(stefan at loplof.de). diff --git a/Documentation/networking/packet_mmap.rst b/Documentation/networking/packet_mmap.rst new file mode 100644 index 0000000000..30a3be3c48 --- /dev/null +++ b/Documentation/networking/packet_mmap.rst @@ -0,0 +1,1083 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=========== +Packet MMAP +=========== + +Abstract +======== + +This file documents the mmap() facility available with the PACKET +socket interface. This type of sockets is used for + +i) capture network traffic with utilities like tcpdump, +ii) transmit network traffic, or any other that needs raw + access to network interface. + +Howto can be found at: + + https://sites.google.com/site/packetmmap/ + +Please send your comments to + - Ulisses Alonso Camaró <uaca@i.hate.spam.alumni.uv.es> + - Johann Baudy + +Why use PACKET_MMAP +=================== + +Non PACKET_MMAP capture process (plain AF_PACKET) is very +inefficient. It uses very limited buffers and requires one system call to +capture each packet, it requires two if you want to get packet's timestamp +(like libpcap always does). + +On the other hand PACKET_MMAP is very efficient. PACKET_MMAP provides a size +configurable circular buffer mapped in user space that can be used to either +send or receive packets. This way reading packets just needs to wait for them, +most of the time there is no need to issue a single system call. Concerning +transmission, multiple packets can be sent through one system call to get the +highest bandwidth. By using a shared buffer between the kernel and the user +also has the benefit of minimizing packet copies. + +It's fine to use PACKET_MMAP to improve the performance of the capture and +transmission process, but it isn't everything. At least, if you are capturing +at high speeds (this is relative to the cpu speed), you should check if the +device driver of your network interface card supports some sort of interrupt +load mitigation or (even better) if it supports NAPI, also make sure it is +enabled. For transmission, check the MTU (Maximum Transmission Unit) used and +supported by devices of your network. CPU IRQ pinning of your network interface +card can also be an advantage. + +How to use mmap() to improve capture process +============================================ + +From the user standpoint, you should use the higher level libpcap library, which +is a de facto standard, portable across nearly all operating systems +including Win32. + +Packet MMAP support was integrated into libpcap around the time of version 1.3.0; +TPACKET_V3 support was added in version 1.5.0 + +How to use mmap() directly to improve capture process +===================================================== + +From the system calls stand point, the use of PACKET_MMAP involves +the following process:: + + + [setup] socket() -------> creation of the capture socket + setsockopt() ---> allocation of the circular buffer (ring) + option: PACKET_RX_RING + mmap() ---------> mapping of the allocated buffer to the + user process + + [capture] poll() ---------> to wait for incoming packets + + [shutdown] close() --------> destruction of the capture socket and + deallocation of all associated + resources. + + +socket creation and destruction is straight forward, and is done +the same way with or without PACKET_MMAP:: + + int fd = socket(PF_PACKET, mode, htons(ETH_P_ALL)); + +where mode is SOCK_RAW for the raw interface were link level +information can be captured or SOCK_DGRAM for the cooked +interface where link level information capture is not +supported and a link level pseudo-header is provided +by the kernel. + +The destruction of the socket and all associated resources +is done by a simple call to close(fd). + +Similarly as without PACKET_MMAP, it is possible to use one socket +for capture and transmission. This can be done by mapping the +allocated RX and TX buffer ring with a single mmap() call. +See "Mapping and use of the circular buffer (ring)". + +Next I will describe PACKET_MMAP settings and its constraints, +also the mapping of the circular buffer in the user process and +the use of this buffer. + +How to use mmap() directly to improve transmission process +========================================================== +Transmission process is similar to capture as shown below:: + + [setup] socket() -------> creation of the transmission socket + setsockopt() ---> allocation of the circular buffer (ring) + option: PACKET_TX_RING + bind() ---------> bind transmission socket with a network interface + mmap() ---------> mapping of the allocated buffer to the + user process + + [transmission] poll() ---------> wait for free packets (optional) + send() ---------> send all packets that are set as ready in + the ring + The flag MSG_DONTWAIT can be used to return + before end of transfer. + + [shutdown] close() --------> destruction of the transmission socket and + deallocation of all associated resources. + +Socket creation and destruction is also straight forward, and is done +the same way as in capturing described in the previous paragraph:: + + int fd = socket(PF_PACKET, mode, 0); + +The protocol can optionally be 0 in case we only want to transmit +via this socket, which avoids an expensive call to packet_rcv(). +In this case, you also need to bind(2) the TX_RING with sll_protocol = 0 +set. Otherwise, htons(ETH_P_ALL) or any other protocol, for example. + +Binding the socket to your network interface is mandatory (with zero copy) to +know the header size of frames used in the circular buffer. + +As capture, each frame contains two parts:: + + -------------------- + | struct tpacket_hdr | Header. It contains the status of + | | of this frame + |--------------------| + | data buffer | + . . Data that will be sent over the network interface. + . . + -------------------- + + bind() associates the socket to your network interface thanks to + sll_ifindex parameter of struct sockaddr_ll. + + Initialization example:: + + struct sockaddr_ll my_addr; + struct ifreq s_ifr; + ... + + strscpy_pad (s_ifr.ifr_name, "eth0", sizeof(s_ifr.ifr_name)); + + /* get interface index of eth0 */ + ioctl(this->socket, SIOCGIFINDEX, &s_ifr); + + /* fill sockaddr_ll struct to prepare binding */ + my_addr.sll_family = AF_PACKET; + my_addr.sll_protocol = htons(ETH_P_ALL); + my_addr.sll_ifindex = s_ifr.ifr_ifindex; + + /* bind socket to eth0 */ + bind(this->socket, (struct sockaddr *)&my_addr, sizeof(struct sockaddr_ll)); + + A complete tutorial is available at: https://sites.google.com/site/packetmmap/ + +By default, the user should put data at:: + + frame base + TPACKET_HDRLEN - sizeof(struct sockaddr_ll) + +So, whatever you choose for the socket mode (SOCK_DGRAM or SOCK_RAW), +the beginning of the user data will be at:: + + frame base + TPACKET_ALIGN(sizeof(struct tpacket_hdr)) + +If you wish to put user data at a custom offset from the beginning of +the frame (for payload alignment with SOCK_RAW mode for instance) you +can set tp_net (with SOCK_DGRAM) or tp_mac (with SOCK_RAW). In order +to make this work it must be enabled previously with setsockopt() +and the PACKET_TX_HAS_OFF option. + +PACKET_MMAP settings +==================== + +To setup PACKET_MMAP from user level code is done with a call like + + - Capture process:: + + setsockopt(fd, SOL_PACKET, PACKET_RX_RING, (void *) &req, sizeof(req)) + + - Transmission process:: + + setsockopt(fd, SOL_PACKET, PACKET_TX_RING, (void *) &req, sizeof(req)) + +The most significant argument in the previous call is the req parameter, +this parameter must to have the following structure:: + + struct tpacket_req + { + unsigned int tp_block_size; /* Minimal size of contiguous block */ + unsigned int tp_block_nr; /* Number of blocks */ + unsigned int tp_frame_size; /* Size of frame */ + unsigned int tp_frame_nr; /* Total number of frames */ + }; + +This structure is defined in /usr/include/linux/if_packet.h and establishes a +circular buffer (ring) of unswappable memory. +Being mapped in the capture process allows reading the captured frames and +related meta-information like timestamps without requiring a system call. + +Frames are grouped in blocks. Each block is a physically contiguous +region of memory and holds tp_block_size/tp_frame_size frames. The total number +of blocks is tp_block_nr. Note that tp_frame_nr is a redundant parameter because:: + + frames_per_block = tp_block_size/tp_frame_size + +indeed, packet_set_ring checks that the following condition is true:: + + frames_per_block * tp_block_nr == tp_frame_nr + +Lets see an example, with the following values:: + + tp_block_size= 4096 + tp_frame_size= 2048 + tp_block_nr = 4 + tp_frame_nr = 8 + +we will get the following buffer structure:: + + block #1 block #2 + +---------+---------+ +---------+---------+ + | frame 1 | frame 2 | | frame 3 | frame 4 | + +---------+---------+ +---------+---------+ + + block #3 block #4 + +---------+---------+ +---------+---------+ + | frame 5 | frame 6 | | frame 7 | frame 8 | + +---------+---------+ +---------+---------+ + +A frame can be of any size with the only condition it can fit in a block. A block +can only hold an integer number of frames, or in other words, a frame cannot +be spawned across two blocks, so there are some details you have to take into +account when choosing the frame_size. See "Mapping and use of the circular +buffer (ring)". + +PACKET_MMAP setting constraints +=============================== + +In kernel versions prior to 2.4.26 (for the 2.4 branch) and 2.6.5 (2.6 branch), +the PACKET_MMAP buffer could hold only 32768 frames in a 32 bit architecture or +16384 in a 64 bit architecture. + +Block size limit +---------------- + +As stated earlier, each block is a contiguous physical region of memory. These +memory regions are allocated with calls to the __get_free_pages() function. As +the name indicates, this function allocates pages of memory, and the second +argument is "order" or a power of two number of pages, that is +(for PAGE_SIZE == 4096) order=0 ==> 4096 bytes, order=1 ==> 8192 bytes, +order=2 ==> 16384 bytes, etc. The maximum size of a +region allocated by __get_free_pages is determined by the MAX_ORDER macro. More +precisely the limit can be calculated as:: + + PAGE_SIZE << MAX_ORDER + + In a i386 architecture PAGE_SIZE is 4096 bytes + In a 2.4/i386 kernel MAX_ORDER is 10 + In a 2.6/i386 kernel MAX_ORDER is 11 + +So get_free_pages can allocate as much as 4MB or 8MB in a 2.4/2.6 kernel +respectively, with an i386 architecture. + +User space programs can include /usr/include/sys/user.h and +/usr/include/linux/mmzone.h to get PAGE_SIZE MAX_ORDER declarations. + +The pagesize can also be determined dynamically with the getpagesize (2) +system call. + +Block number limit +------------------ + +To understand the constraints of PACKET_MMAP, we have to see the structure +used to hold the pointers to each block. + +Currently, this structure is a dynamically allocated vector with kmalloc +called pg_vec, its size limits the number of blocks that can be allocated:: + + +---+---+---+---+ + | x | x | x | x | + +---+---+---+---+ + | | | | + | | | v + | | v block #4 + | v block #3 + v block #2 + block #1 + +kmalloc allocates any number of bytes of physically contiguous memory from +a pool of pre-determined sizes. This pool of memory is maintained by the slab +allocator which is at the end the responsible for doing the allocation and +hence which imposes the maximum memory that kmalloc can allocate. + +In a 2.4/2.6 kernel and the i386 architecture, the limit is 131072 bytes. The +predetermined sizes that kmalloc uses can be checked in the "size-<bytes>" +entries of /proc/slabinfo + +In a 32 bit architecture, pointers are 4 bytes long, so the total number of +pointers to blocks is:: + + 131072/4 = 32768 blocks + +PACKET_MMAP buffer size calculator +================================== + +Definitions: + +============== ================================================================ +<size-max> is the maximum size of allocable with kmalloc + (see /proc/slabinfo) +<pointer size> depends on the architecture -- ``sizeof(void *)`` +<page size> depends on the architecture -- PAGE_SIZE or getpagesize (2) +<max-order> is the value defined with MAX_ORDER +<frame size> it's an upper bound of frame's capture size (more on this later) +============== ================================================================ + +from these definitions we will derive:: + + <block number> = <size-max>/<pointer size> + <block size> = <pagesize> << <max-order> + +so, the max buffer size is:: + + <block number> * <block size> + +and, the number of frames be:: + + <block number> * <block size> / <frame size> + +Suppose the following parameters, which apply for 2.6 kernel and an +i386 architecture:: + + <size-max> = 131072 bytes + <pointer size> = 4 bytes + <pagesize> = 4096 bytes + <max-order> = 11 + +and a value for <frame size> of 2048 bytes. These parameters will yield:: + + <block number> = 131072/4 = 32768 blocks + <block size> = 4096 << 11 = 8 MiB. + +and hence the buffer will have a 262144 MiB size. So it can hold +262144 MiB / 2048 bytes = 134217728 frames + +Actually, this buffer size is not possible with an i386 architecture. +Remember that the memory is allocated in kernel space, in the case of +an i386 kernel's memory size is limited to 1GiB. + +All memory allocations are not freed until the socket is closed. The memory +allocations are done with GFP_KERNEL priority, this basically means that +the allocation can wait and swap other process' memory in order to allocate +the necessary memory, so normally limits can be reached. + +Other constraints +----------------- + +If you check the source code you will see that what I draw here as a frame +is not only the link level frame. At the beginning of each frame there is a +header called struct tpacket_hdr used in PACKET_MMAP to hold link level's frame +meta information like timestamp. So what we draw here a frame it's really +the following (from include/linux/if_packet.h):: + + /* + Frame structure: + + - Start. Frame must be aligned to TPACKET_ALIGNMENT=16 + - struct tpacket_hdr + - pad to TPACKET_ALIGNMENT=16 + - struct sockaddr_ll + - Gap, chosen so that packet data (Start+tp_net) aligns to + TPACKET_ALIGNMENT=16 + - Start+tp_mac: [ Optional MAC header ] + - Start+tp_net: Packet data, aligned to TPACKET_ALIGNMENT=16. + - Pad to align to TPACKET_ALIGNMENT=16 + */ + +The following are conditions that are checked in packet_set_ring + + - tp_block_size must be a multiple of PAGE_SIZE (1) + - tp_frame_size must be greater than TPACKET_HDRLEN (obvious) + - tp_frame_size must be a multiple of TPACKET_ALIGNMENT + - tp_frame_nr must be exactly frames_per_block*tp_block_nr + +Note that tp_block_size should be chosen to be a power of two or there will +be a waste of memory. + +Mapping and use of the circular buffer (ring) +--------------------------------------------- + +The mapping of the buffer in the user process is done with the conventional +mmap function. Even the circular buffer is compound of several physically +discontiguous blocks of memory, they are contiguous to the user space, hence +just one call to mmap is needed:: + + mmap(0, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); + +If tp_frame_size is a divisor of tp_block_size frames will be +contiguously spaced by tp_frame_size bytes. If not, each +tp_block_size/tp_frame_size frames there will be a gap between +the frames. This is because a frame cannot be spawn across two +blocks. + +To use one socket for capture and transmission, the mapping of both the +RX and TX buffer ring has to be done with one call to mmap:: + + ... + setsockopt(fd, SOL_PACKET, PACKET_RX_RING, &foo, sizeof(foo)); + setsockopt(fd, SOL_PACKET, PACKET_TX_RING, &bar, sizeof(bar)); + ... + rx_ring = mmap(0, size * 2, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); + tx_ring = rx_ring + size; + +RX must be the first as the kernel maps the TX ring memory right +after the RX one. + +At the beginning of each frame there is an status field (see +struct tpacket_hdr). If this field is 0 means that the frame is ready +to be used for the kernel, If not, there is a frame the user can read +and the following flags apply: + +Capture process +^^^^^^^^^^^^^^^ + +From include/linux/if_packet.h:: + + #define TP_STATUS_COPY (1 << 1) + #define TP_STATUS_LOSING (1 << 2) + #define TP_STATUS_CSUMNOTREADY (1 << 3) + #define TP_STATUS_CSUM_VALID (1 << 7) + +====================== ======================================================= +TP_STATUS_COPY This flag indicates that the frame (and associated + meta information) has been truncated because it's + larger than tp_frame_size. This packet can be + read entirely with recvfrom(). + + In order to make this work it must to be + enabled previously with setsockopt() and + the PACKET_COPY_THRESH option. + + The number of frames that can be buffered to + be read with recvfrom is limited like a normal socket. + See the SO_RCVBUF option in the socket (7) man page. + +TP_STATUS_LOSING indicates there were packet drops from last time + statistics where checked with getsockopt() and + the PACKET_STATISTICS option. + +TP_STATUS_CSUMNOTREADY currently it's used for outgoing IP packets which + its checksum will be done in hardware. So while + reading the packet we should not try to check the + checksum. + +TP_STATUS_CSUM_VALID This flag indicates that at least the transport + header checksum of the packet has been already + validated on the kernel side. If the flag is not set + then we are free to check the checksum by ourselves + provided that TP_STATUS_CSUMNOTREADY is also not set. +====================== ======================================================= + +for convenience there are also the following defines:: + + #define TP_STATUS_KERNEL 0 + #define TP_STATUS_USER 1 + +The kernel initializes all frames to TP_STATUS_KERNEL, when the kernel +receives a packet it puts in the buffer and updates the status with +at least the TP_STATUS_USER flag. Then the user can read the packet, +once the packet is read the user must zero the status field, so the kernel +can use again that frame buffer. + +The user can use poll (any other variant should apply too) to check if new +packets are in the ring:: + + struct pollfd pfd; + + pfd.fd = fd; + pfd.revents = 0; + pfd.events = POLLIN|POLLRDNORM|POLLERR; + + if (status == TP_STATUS_KERNEL) + retval = poll(&pfd, 1, timeout); + +It doesn't incur in a race condition to first check the status value and +then poll for frames. + +Transmission process +^^^^^^^^^^^^^^^^^^^^ + +Those defines are also used for transmission:: + + #define TP_STATUS_AVAILABLE 0 // Frame is available + #define TP_STATUS_SEND_REQUEST 1 // Frame will be sent on next send() + #define TP_STATUS_SENDING 2 // Frame is currently in transmission + #define TP_STATUS_WRONG_FORMAT 4 // Frame format is not correct + +First, the kernel initializes all frames to TP_STATUS_AVAILABLE. To send a +packet, the user fills a data buffer of an available frame, sets tp_len to +current data buffer size and sets its status field to TP_STATUS_SEND_REQUEST. +This can be done on multiple frames. Once the user is ready to transmit, it +calls send(). Then all buffers with status equal to TP_STATUS_SEND_REQUEST are +forwarded to the network device. The kernel updates each status of sent +frames with TP_STATUS_SENDING until the end of transfer. + +At the end of each transfer, buffer status returns to TP_STATUS_AVAILABLE. + +:: + + header->tp_len = in_i_size; + header->tp_status = TP_STATUS_SEND_REQUEST; + retval = send(this->socket, NULL, 0, 0); + +The user can also use poll() to check if a buffer is available: + +(status == TP_STATUS_SENDING) + +:: + + struct pollfd pfd; + pfd.fd = fd; + pfd.revents = 0; + pfd.events = POLLOUT; + retval = poll(&pfd, 1, timeout); + +What TPACKET versions are available and when to use them? +========================================================= + +:: + + int val = tpacket_version; + setsockopt(fd, SOL_PACKET, PACKET_VERSION, &val, sizeof(val)); + getsockopt(fd, SOL_PACKET, PACKET_VERSION, &val, sizeof(val)); + +where 'tpacket_version' can be TPACKET_V1 (default), TPACKET_V2, TPACKET_V3. + +TPACKET_V1: + - Default if not otherwise specified by setsockopt(2) + - RX_RING, TX_RING available + +TPACKET_V1 --> TPACKET_V2: + - Made 64 bit clean due to unsigned long usage in TPACKET_V1 + structures, thus this also works on 64 bit kernel with 32 bit + userspace and the like + - Timestamp resolution in nanoseconds instead of microseconds + - RX_RING, TX_RING available + - VLAN metadata information available for packets + (TP_STATUS_VLAN_VALID, TP_STATUS_VLAN_TPID_VALID), + in the tpacket2_hdr structure: + + - TP_STATUS_VLAN_VALID bit being set into the tp_status field indicates + that the tp_vlan_tci field has valid VLAN TCI value + - TP_STATUS_VLAN_TPID_VALID bit being set into the tp_status field + indicates that the tp_vlan_tpid field has valid VLAN TPID value + + - How to switch to TPACKET_V2: + + 1. Replace struct tpacket_hdr by struct tpacket2_hdr + 2. Query header len and save + 3. Set protocol version to 2, set up ring as usual + 4. For getting the sockaddr_ll, + use ``(void *)hdr + TPACKET_ALIGN(hdrlen)`` instead of + ``(void *)hdr + TPACKET_ALIGN(sizeof(struct tpacket_hdr))`` + +TPACKET_V2 --> TPACKET_V3: + - Flexible buffer implementation for RX_RING: + 1. Blocks can be configured with non-static frame-size + 2. Read/poll is at a block-level (as opposed to packet-level) + 3. Added poll timeout to avoid indefinite user-space wait + on idle links + 4. Added user-configurable knobs: + + 4.1 block::timeout + 4.2 tpkt_hdr::sk_rxhash + + - RX Hash data available in user space + - TX_RING semantics are conceptually similar to TPACKET_V2; + use tpacket3_hdr instead of tpacket2_hdr, and TPACKET3_HDRLEN + instead of TPACKET2_HDRLEN. In the current implementation, + the tp_next_offset field in the tpacket3_hdr MUST be set to + zero, indicating that the ring does not hold variable sized frames. + Packets with non-zero values of tp_next_offset will be dropped. + +AF_PACKET fanout mode +===================== + +In the AF_PACKET fanout mode, packet reception can be load balanced among +processes. This also works in combination with mmap(2) on packet sockets. + +Currently implemented fanout policies are: + + - PACKET_FANOUT_HASH: schedule to socket by skb's packet hash + - PACKET_FANOUT_LB: schedule to socket by round-robin + - PACKET_FANOUT_CPU: schedule to socket by CPU packet arrives on + - PACKET_FANOUT_RND: schedule to socket by random selection + - PACKET_FANOUT_ROLLOVER: if one socket is full, rollover to another + - PACKET_FANOUT_QM: schedule to socket by skbs recorded queue_mapping + +Minimal example code by David S. Miller (try things like "./test eth0 hash", +"./test eth0 lb", etc.):: + + #include <stddef.h> + #include <stdlib.h> + #include <stdio.h> + #include <string.h> + + #include <sys/types.h> + #include <sys/wait.h> + #include <sys/socket.h> + #include <sys/ioctl.h> + + #include <unistd.h> + + #include <linux/if_ether.h> + #include <linux/if_packet.h> + + #include <net/if.h> + + static const char *device_name; + static int fanout_type; + static int fanout_id; + + #ifndef PACKET_FANOUT + # define PACKET_FANOUT 18 + # define PACKET_FANOUT_HASH 0 + # define PACKET_FANOUT_LB 1 + #endif + + static int setup_socket(void) + { + int err, fd = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_IP)); + struct sockaddr_ll ll; + struct ifreq ifr; + int fanout_arg; + + if (fd < 0) { + perror("socket"); + return EXIT_FAILURE; + } + + memset(&ifr, 0, sizeof(ifr)); + strcpy(ifr.ifr_name, device_name); + err = ioctl(fd, SIOCGIFINDEX, &ifr); + if (err < 0) { + perror("SIOCGIFINDEX"); + return EXIT_FAILURE; + } + + memset(&ll, 0, sizeof(ll)); + ll.sll_family = AF_PACKET; + ll.sll_ifindex = ifr.ifr_ifindex; + err = bind(fd, (struct sockaddr *) &ll, sizeof(ll)); + if (err < 0) { + perror("bind"); + return EXIT_FAILURE; + } + + fanout_arg = (fanout_id | (fanout_type << 16)); + err = setsockopt(fd, SOL_PACKET, PACKET_FANOUT, + &fanout_arg, sizeof(fanout_arg)); + if (err) { + perror("setsockopt"); + return EXIT_FAILURE; + } + + return fd; + } + + static void fanout_thread(void) + { + int fd = setup_socket(); + int limit = 10000; + + if (fd < 0) + exit(fd); + + while (limit-- > 0) { + char buf[1600]; + int err; + + err = read(fd, buf, sizeof(buf)); + if (err < 0) { + perror("read"); + exit(EXIT_FAILURE); + } + if ((limit % 10) == 0) + fprintf(stdout, "(%d) \n", getpid()); + } + + fprintf(stdout, "%d: Received 10000 packets\n", getpid()); + + close(fd); + exit(0); + } + + int main(int argc, char **argp) + { + int fd, err; + int i; + + if (argc != 3) { + fprintf(stderr, "Usage: %s INTERFACE {hash|lb}\n", argp[0]); + return EXIT_FAILURE; + } + + if (!strcmp(argp[2], "hash")) + fanout_type = PACKET_FANOUT_HASH; + else if (!strcmp(argp[2], "lb")) + fanout_type = PACKET_FANOUT_LB; + else { + fprintf(stderr, "Unknown fanout type [%s]\n", argp[2]); + exit(EXIT_FAILURE); + } + + device_name = argp[1]; + fanout_id = getpid() & 0xffff; + + for (i = 0; i < 4; i++) { + pid_t pid = fork(); + + switch (pid) { + case 0: + fanout_thread(); + + case -1: + perror("fork"); + exit(EXIT_FAILURE); + } + } + + for (i = 0; i < 4; i++) { + int status; + + wait(&status); + } + + return 0; + } + +AF_PACKET TPACKET_V3 example +============================ + +AF_PACKET's TPACKET_V3 ring buffer can be configured to use non-static frame +sizes by doing its own memory management. It is based on blocks where polling +works on a per block basis instead of per ring as in TPACKET_V2 and predecessor. + +It is said that TPACKET_V3 brings the following benefits: + + * ~15% - 20% reduction in CPU-usage + * ~20% increase in packet capture rate + * ~2x increase in packet density + * Port aggregation analysis + * Non static frame size to capture entire packet payload + +So it seems to be a good candidate to be used with packet fanout. + +Minimal example code by Daniel Borkmann based on Chetan Loke's lolpcap (compile +it with gcc -Wall -O2 blob.c, and try things like "./a.out eth0", etc.):: + + /* Written from scratch, but kernel-to-user space API usage + * dissected from lolpcap: + * Copyright 2011, Chetan Loke <loke.chetan@gmail.com> + * License: GPL, version 2.0 + */ + + #include <stdio.h> + #include <stdlib.h> + #include <stdint.h> + #include <string.h> + #include <assert.h> + #include <net/if.h> + #include <arpa/inet.h> + #include <netdb.h> + #include <poll.h> + #include <unistd.h> + #include <signal.h> + #include <inttypes.h> + #include <sys/socket.h> + #include <sys/mman.h> + #include <linux/if_packet.h> + #include <linux/if_ether.h> + #include <linux/ip.h> + + #ifndef likely + # define likely(x) __builtin_expect(!!(x), 1) + #endif + #ifndef unlikely + # define unlikely(x) __builtin_expect(!!(x), 0) + #endif + + struct block_desc { + uint32_t version; + uint32_t offset_to_priv; + struct tpacket_hdr_v1 h1; + }; + + struct ring { + struct iovec *rd; + uint8_t *map; + struct tpacket_req3 req; + }; + + static unsigned long packets_total = 0, bytes_total = 0; + static sig_atomic_t sigint = 0; + + static void sighandler(int num) + { + sigint = 1; + } + + static int setup_socket(struct ring *ring, char *netdev) + { + int err, i, fd, v = TPACKET_V3; + struct sockaddr_ll ll; + unsigned int blocksiz = 1 << 22, framesiz = 1 << 11; + unsigned int blocknum = 64; + + fd = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL)); + if (fd < 0) { + perror("socket"); + exit(1); + } + + err = setsockopt(fd, SOL_PACKET, PACKET_VERSION, &v, sizeof(v)); + if (err < 0) { + perror("setsockopt"); + exit(1); + } + + memset(&ring->req, 0, sizeof(ring->req)); + ring->req.tp_block_size = blocksiz; + ring->req.tp_frame_size = framesiz; + ring->req.tp_block_nr = blocknum; + ring->req.tp_frame_nr = (blocksiz * blocknum) / framesiz; + ring->req.tp_retire_blk_tov = 60; + ring->req.tp_feature_req_word = TP_FT_REQ_FILL_RXHASH; + + err = setsockopt(fd, SOL_PACKET, PACKET_RX_RING, &ring->req, + sizeof(ring->req)); + if (err < 0) { + perror("setsockopt"); + exit(1); + } + + ring->map = mmap(NULL, ring->req.tp_block_size * ring->req.tp_block_nr, + PROT_READ | PROT_WRITE, MAP_SHARED | MAP_LOCKED, fd, 0); + if (ring->map == MAP_FAILED) { + perror("mmap"); + exit(1); + } + + ring->rd = malloc(ring->req.tp_block_nr * sizeof(*ring->rd)); + assert(ring->rd); + for (i = 0; i < ring->req.tp_block_nr; ++i) { + ring->rd[i].iov_base = ring->map + (i * ring->req.tp_block_size); + ring->rd[i].iov_len = ring->req.tp_block_size; + } + + memset(&ll, 0, sizeof(ll)); + ll.sll_family = PF_PACKET; + ll.sll_protocol = htons(ETH_P_ALL); + ll.sll_ifindex = if_nametoindex(netdev); + ll.sll_hatype = 0; + ll.sll_pkttype = 0; + ll.sll_halen = 0; + + err = bind(fd, (struct sockaddr *) &ll, sizeof(ll)); + if (err < 0) { + perror("bind"); + exit(1); + } + + return fd; + } + + static void display(struct tpacket3_hdr *ppd) + { + struct ethhdr *eth = (struct ethhdr *) ((uint8_t *) ppd + ppd->tp_mac); + struct iphdr *ip = (struct iphdr *) ((uint8_t *) eth + ETH_HLEN); + + if (eth->h_proto == htons(ETH_P_IP)) { + struct sockaddr_in ss, sd; + char sbuff[NI_MAXHOST], dbuff[NI_MAXHOST]; + + memset(&ss, 0, sizeof(ss)); + ss.sin_family = PF_INET; + ss.sin_addr.s_addr = ip->saddr; + getnameinfo((struct sockaddr *) &ss, sizeof(ss), + sbuff, sizeof(sbuff), NULL, 0, NI_NUMERICHOST); + + memset(&sd, 0, sizeof(sd)); + sd.sin_family = PF_INET; + sd.sin_addr.s_addr = ip->daddr; + getnameinfo((struct sockaddr *) &sd, sizeof(sd), + dbuff, sizeof(dbuff), NULL, 0, NI_NUMERICHOST); + + printf("%s -> %s, ", sbuff, dbuff); + } + + printf("rxhash: 0x%x\n", ppd->hv1.tp_rxhash); + } + + static void walk_block(struct block_desc *pbd, const int block_num) + { + int num_pkts = pbd->h1.num_pkts, i; + unsigned long bytes = 0; + struct tpacket3_hdr *ppd; + + ppd = (struct tpacket3_hdr *) ((uint8_t *) pbd + + pbd->h1.offset_to_first_pkt); + for (i = 0; i < num_pkts; ++i) { + bytes += ppd->tp_snaplen; + display(ppd); + + ppd = (struct tpacket3_hdr *) ((uint8_t *) ppd + + ppd->tp_next_offset); + } + + packets_total += num_pkts; + bytes_total += bytes; + } + + static void flush_block(struct block_desc *pbd) + { + pbd->h1.block_status = TP_STATUS_KERNEL; + } + + static void teardown_socket(struct ring *ring, int fd) + { + munmap(ring->map, ring->req.tp_block_size * ring->req.tp_block_nr); + free(ring->rd); + close(fd); + } + + int main(int argc, char **argp) + { + int fd, err; + socklen_t len; + struct ring ring; + struct pollfd pfd; + unsigned int block_num = 0, blocks = 64; + struct block_desc *pbd; + struct tpacket_stats_v3 stats; + + if (argc != 2) { + fprintf(stderr, "Usage: %s INTERFACE\n", argp[0]); + return EXIT_FAILURE; + } + + signal(SIGINT, sighandler); + + memset(&ring, 0, sizeof(ring)); + fd = setup_socket(&ring, argp[argc - 1]); + assert(fd > 0); + + memset(&pfd, 0, sizeof(pfd)); + pfd.fd = fd; + pfd.events = POLLIN | POLLERR; + pfd.revents = 0; + + while (likely(!sigint)) { + pbd = (struct block_desc *) ring.rd[block_num].iov_base; + + if ((pbd->h1.block_status & TP_STATUS_USER) == 0) { + poll(&pfd, 1, -1); + continue; + } + + walk_block(pbd, block_num); + flush_block(pbd); + block_num = (block_num + 1) % blocks; + } + + len = sizeof(stats); + err = getsockopt(fd, SOL_PACKET, PACKET_STATISTICS, &stats, &len); + if (err < 0) { + perror("getsockopt"); + exit(1); + } + + fflush(stdout); + printf("\nReceived %u packets, %lu bytes, %u dropped, freeze_q_cnt: %u\n", + stats.tp_packets, bytes_total, stats.tp_drops, + stats.tp_freeze_q_cnt); + + teardown_socket(&ring, fd); + return 0; + } + +PACKET_QDISC_BYPASS +=================== + +If there is a requirement to load the network with many packets in a similar +fashion as pktgen does, you might set the following option after socket +creation:: + + int one = 1; + setsockopt(fd, SOL_PACKET, PACKET_QDISC_BYPASS, &one, sizeof(one)); + +This has the side-effect, that packets sent through PF_PACKET will bypass the +kernel's qdisc layer and are forcedly pushed to the driver directly. Meaning, +packet are not buffered, tc disciplines are ignored, increased loss can occur +and such packets are also not visible to other PF_PACKET sockets anymore. So, +you have been warned; generally, this can be useful for stress testing various +components of a system. + +On default, PACKET_QDISC_BYPASS is disabled and needs to be explicitly enabled +on PF_PACKET sockets. + +PACKET_TIMESTAMP +================ + +The PACKET_TIMESTAMP setting determines the source of the timestamp in +the packet meta information for mmap(2)ed RX_RING and TX_RINGs. If your +NIC is capable of timestamping packets in hardware, you can request those +hardware timestamps to be used. Note: you may need to enable the generation +of hardware timestamps with SIOCSHWTSTAMP (see related information from +Documentation/networking/timestamping.rst). + +PACKET_TIMESTAMP accepts the same integer bit field as SO_TIMESTAMPING:: + + int req = SOF_TIMESTAMPING_RAW_HARDWARE; + setsockopt(fd, SOL_PACKET, PACKET_TIMESTAMP, (void *) &req, sizeof(req)) + +For the mmap(2)ed ring buffers, such timestamps are stored in the +``tpacket{,2,3}_hdr`` structure's tp_sec and ``tp_{n,u}sec`` members. +To determine what kind of timestamp has been reported, the tp_status field +is binary or'ed with the following possible bits ... + +:: + + TP_STATUS_TS_RAW_HARDWARE + TP_STATUS_TS_SOFTWARE + +... that are equivalent to its ``SOF_TIMESTAMPING_*`` counterparts. For the +RX_RING, if neither is set (i.e. PACKET_TIMESTAMP is not set), then a +software fallback was invoked *within* PF_PACKET's processing code (less +precise). + +Getting timestamps for the TX_RING works as follows: i) fill the ring frames, +ii) call sendto() e.g. in blocking mode, iii) wait for status of relevant +frames to be updated resp. the frame handed over to the application, iv) walk +through the frames to pick up the individual hw/sw timestamps. + +Only (!) if transmit timestamping is enabled, then these bits are combined +with binary | with TP_STATUS_AVAILABLE, so you must check for that in your +application (e.g. !(tp_status & (TP_STATUS_SEND_REQUEST | TP_STATUS_SENDING)) +in a first step to see if the frame belongs to the application, and then +one can extract the type of timestamp in a second step from tp_status)! + +If you don't care about them, thus having it disabled, checking for +TP_STATUS_AVAILABLE resp. TP_STATUS_WRONG_FORMAT is sufficient. If in the +TX_RING part only TP_STATUS_AVAILABLE is set, then the tp_sec and tp_{n,u}sec +members do not contain a valid value. For TX_RINGs, by default no timestamp +is generated! + +See include/linux/net_tstamp.h and Documentation/networking/timestamping.rst +for more information on hardware timestamps. + +Miscellaneous bits +================== + +- Packet sockets work well together with Linux socket filters, thus you also + might want to have a look at Documentation/networking/filter.rst + +THANKS +====== + + Jesse Brandeburg, for fixing my grammathical/spelling errors diff --git a/Documentation/networking/page_pool.rst b/Documentation/networking/page_pool.rst new file mode 100644 index 0000000000..215ebc9275 --- /dev/null +++ b/Documentation/networking/page_pool.rst @@ -0,0 +1,191 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============= +Page Pool API +============= + +.. kernel-doc:: include/net/page_pool/helpers.h + :doc: page_pool allocator + +Architecture overview +===================== + +.. code-block:: none + + +------------------+ + | Driver | + +------------------+ + ^ + | + | + | + v + +--------------------------------------------+ + | request memory | + +--------------------------------------------+ + ^ ^ + | | + | Pool empty | Pool has entries + | | + v v + +-----------------------+ +------------------------+ + | alloc (and map) pages | | get page from cache | + +-----------------------+ +------------------------+ + ^ ^ + | | + | cache available | No entries, refill + | | from ptr-ring + | | + v v + +-----------------+ +------------------+ + | Fast cache | | ptr-ring cache | + +-----------------+ +------------------+ + +API interface +============= +The number of pools created **must** match the number of hardware queues +unless hardware restrictions make that impossible. This would otherwise beat the +purpose of page pool, which is allocate pages fast from cache without locking. +This lockless guarantee naturally comes from running under a NAPI softirq. +The protection doesn't strictly have to be NAPI, any guarantee that allocating +a page will cause no race conditions is enough. + +.. kernel-doc:: net/core/page_pool.c + :identifiers: page_pool_create + +.. kernel-doc:: include/net/page_pool/types.h + :identifiers: struct page_pool_params + +.. kernel-doc:: include/net/page_pool/helpers.h + :identifiers: page_pool_put_page page_pool_put_full_page + page_pool_recycle_direct page_pool_dev_alloc_pages + page_pool_get_dma_addr page_pool_get_dma_dir + +.. kernel-doc:: net/core/page_pool.c + :identifiers: page_pool_put_page_bulk page_pool_get_stats + +DMA sync +-------- +Driver is always responsible for syncing the pages for the CPU. +Drivers may choose to take care of syncing for the device as well +or set the ``PP_FLAG_DMA_SYNC_DEV`` flag to request that pages +allocated from the page pool are already synced for the device. + +If ``PP_FLAG_DMA_SYNC_DEV`` is set, the driver must inform the core what portion +of the buffer has to be synced. This allows the core to avoid syncing the entire +page when the drivers knows that the device only accessed a portion of the page. + +Most drivers will reserve headroom in front of the frame. This part +of the buffer is not touched by the device, so to avoid syncing +it drivers can set the ``offset`` field in struct page_pool_params +appropriately. + +For pages recycled on the XDP xmit and skb paths the page pool will +use the ``max_len`` member of struct page_pool_params to decide how +much of the page needs to be synced (starting at ``offset``). +When directly freeing pages in the driver (page_pool_put_page()) +the ``dma_sync_size`` argument specifies how much of the buffer needs +to be synced. + +If in doubt set ``offset`` to 0, ``max_len`` to ``PAGE_SIZE`` and +pass -1 as ``dma_sync_size``. That combination of arguments is always +correct. + +Note that the syncing parameters are for the entire page. +This is important to remember when using fragments (``PP_FLAG_PAGE_FRAG``), +where allocated buffers may be smaller than a full page. +Unless the driver author really understands page pool internals +it's recommended to always use ``offset = 0``, ``max_len = PAGE_SIZE`` +with fragmented page pools. + +Stats API and structures +------------------------ +If the kernel is configured with ``CONFIG_PAGE_POOL_STATS=y``, the API +page_pool_get_stats() and structures described below are available. +It takes a pointer to a ``struct page_pool`` and a pointer to a struct +page_pool_stats allocated by the caller. + +The API will fill in the provided struct page_pool_stats with +statistics about the page_pool. + +.. kernel-doc:: include/net/page_pool/types.h + :identifiers: struct page_pool_recycle_stats + struct page_pool_alloc_stats + struct page_pool_stats + +Coding examples +=============== + +Registration +------------ + +.. code-block:: c + + /* Page pool registration */ + struct page_pool_params pp_params = { 0 }; + struct xdp_rxq_info xdp_rxq; + int err; + + pp_params.order = 0; + /* internal DMA mapping in page_pool */ + pp_params.flags = PP_FLAG_DMA_MAP; + pp_params.pool_size = DESC_NUM; + pp_params.nid = NUMA_NO_NODE; + pp_params.dev = priv->dev; + pp_params.napi = napi; /* only if locking is tied to NAPI */ + pp_params.dma_dir = xdp_prog ? DMA_BIDIRECTIONAL : DMA_FROM_DEVICE; + page_pool = page_pool_create(&pp_params); + + err = xdp_rxq_info_reg(&xdp_rxq, ndev, 0); + if (err) + goto err_out; + + err = xdp_rxq_info_reg_mem_model(&xdp_rxq, MEM_TYPE_PAGE_POOL, page_pool); + if (err) + goto err_out; + +NAPI poller +----------- + + +.. code-block:: c + + /* NAPI Rx poller */ + enum dma_data_direction dma_dir; + + dma_dir = page_pool_get_dma_dir(dring->page_pool); + while (done < budget) { + if (some error) + page_pool_recycle_direct(page_pool, page); + if (packet_is_xdp) { + if XDP_DROP: + page_pool_recycle_direct(page_pool, page); + } else (packet_is_skb) { + skb_mark_for_recycle(skb); + new_page = page_pool_dev_alloc_pages(page_pool); + } + } + +Stats +----- + +.. code-block:: c + + #ifdef CONFIG_PAGE_POOL_STATS + /* retrieve stats */ + struct page_pool_stats stats = { 0 }; + if (page_pool_get_stats(page_pool, &stats)) { + /* perhaps the driver reports statistics with ethool */ + ethtool_print_allocation_stats(&stats.alloc_stats); + ethtool_print_recycle_stats(&stats.recycle_stats); + } + #endif + +Driver unload +------------- + +.. code-block:: c + + /* Driver unload */ + page_pool_put_full_page(page_pool, page, false); + xdp_rxq_info_unreg(&xdp_rxq); diff --git a/Documentation/networking/phonet.rst b/Documentation/networking/phonet.rst new file mode 100644 index 0000000000..d705cc5b09 --- /dev/null +++ b/Documentation/networking/phonet.rst @@ -0,0 +1,230 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> + +============================ +Linux Phonet protocol family +============================ + +Introduction +------------ + +Phonet is a packet protocol used by Nokia cellular modems for both IPC +and RPC. With the Linux Phonet socket family, Linux host processes can +receive and send messages from/to the modem, or any other external +device attached to the modem. The modem takes care of routing. + +Phonet packets can be exchanged through various hardware connections +depending on the device, such as: + + - USB with the CDC Phonet interface, + - infrared, + - Bluetooth, + - an RS232 serial port (with a dedicated "FBUS" line discipline), + - the SSI bus with some TI OMAP processors. + + +Packets format +-------------- + +Phonet packets have a common header as follows:: + + struct phonethdr { + uint8_t pn_media; /* Media type (link-layer identifier) */ + uint8_t pn_rdev; /* Receiver device ID */ + uint8_t pn_sdev; /* Sender device ID */ + uint8_t pn_res; /* Resource ID or function */ + uint16_t pn_length; /* Big-endian message byte length (minus 6) */ + uint8_t pn_robj; /* Receiver object ID */ + uint8_t pn_sobj; /* Sender object ID */ + }; + +On Linux, the link-layer header includes the pn_media byte (see below). +The next 7 bytes are part of the network-layer header. + +The device ID is split: the 6 higher-order bits constitute the device +address, while the 2 lower-order bits are used for multiplexing, as are +the 8-bit object identifiers. As such, Phonet can be considered as a +network layer with 6 bits of address space and 10 bits for transport +protocol (much like port numbers in IP world). + +The modem always has address number zero. All other device have a their +own 6-bit address. + + +Link layer +---------- + +Phonet links are always point-to-point links. The link layer header +consists of a single Phonet media type byte. It uniquely identifies the +link through which the packet is transmitted, from the modem's +perspective. Each Phonet network device shall prepend and set the media +type byte as appropriate. For convenience, a common phonet_header_ops +link-layer header operations structure is provided. It sets the +media type according to the network device hardware address. + +Linux Phonet network interfaces support a dedicated link layer packets +type (ETH_P_PHONET) which is out of the Ethernet type range. They can +only send and receive Phonet packets. + +The virtual TUN tunnel device driver can also be used for Phonet. This +requires IFF_TUN mode, _without_ the IFF_NO_PI flag. In this case, +there is no link-layer header, so there is no Phonet media type byte. + +Note that Phonet interfaces are not allowed to re-order packets, so +only the (default) Linux FIFO qdisc should be used with them. + + +Network layer +------------- + +The Phonet socket address family maps the Phonet packet header:: + + struct sockaddr_pn { + sa_family_t spn_family; /* AF_PHONET */ + uint8_t spn_obj; /* Object ID */ + uint8_t spn_dev; /* Device ID */ + uint8_t spn_resource; /* Resource or function */ + uint8_t spn_zero[...]; /* Padding */ + }; + +The resource field is only used when sending and receiving; +It is ignored by bind() and getsockname(). + + +Low-level datagram protocol +--------------------------- + +Applications can send Phonet messages using the Phonet datagram socket +protocol from the PF_PHONET family. Each socket is bound to one of the +2^10 object IDs available, and can send and receive packets with any +other peer. + +:: + + struct sockaddr_pn addr = { .spn_family = AF_PHONET, }; + ssize_t len; + socklen_t addrlen = sizeof(addr); + int fd; + + fd = socket(PF_PHONET, SOCK_DGRAM, 0); + bind(fd, (struct sockaddr *)&addr, sizeof(addr)); + /* ... */ + + sendto(fd, msg, msglen, 0, (struct sockaddr *)&addr, sizeof(addr)); + len = recvfrom(fd, buf, sizeof(buf), 0, + (struct sockaddr *)&addr, &addrlen); + +This protocol follows the SOCK_DGRAM connection-less semantics. +However, connect() and getpeername() are not supported, as they did +not seem useful with Phonet usages (could be added easily). + + +Resource subscription +--------------------- + +A Phonet datagram socket can be subscribed to any number of 8-bits +Phonet resources, as follow:: + + uint32_t res = 0xXX; + ioctl(fd, SIOCPNADDRESOURCE, &res); + +Subscription is similarly cancelled using the SIOCPNDELRESOURCE I/O +control request, or when the socket is closed. + +Note that no more than one socket can be subscribed to any given +resource at a time. If not, ioctl() will return EBUSY. + + +Phonet Pipe protocol +-------------------- + +The Phonet Pipe protocol is a simple sequenced packets protocol +with end-to-end congestion control. It uses the passive listening +socket paradigm. The listening socket is bound to an unique free object +ID. Each listening socket can handle up to 255 simultaneous +connections, one per accept()'d socket. + +:: + + int lfd, cfd; + + lfd = socket(PF_PHONET, SOCK_SEQPACKET, PN_PROTO_PIPE); + listen (lfd, INT_MAX); + + /* ... */ + cfd = accept(lfd, NULL, NULL); + for (;;) + { + char buf[...]; + ssize_t len = read(cfd, buf, sizeof(buf)); + + /* ... */ + + write(cfd, msg, msglen); + } + +Connections are traditionally established between two endpoints by a +"third party" application. This means that both endpoints are passive. + + +As of Linux kernel version 2.6.39, it is also possible to connect +two endpoints directly, using connect() on the active side. This is +intended to support the newer Nokia Wireless Modem API, as found in +e.g. the Nokia Slim Modem in the ST-Ericsson U8500 platform:: + + struct sockaddr_spn spn; + int fd; + + fd = socket(PF_PHONET, SOCK_SEQPACKET, PN_PROTO_PIPE); + memset(&spn, 0, sizeof(spn)); + spn.spn_family = AF_PHONET; + spn.spn_obj = ...; + spn.spn_dev = ...; + spn.spn_resource = 0xD9; + connect(fd, (struct sockaddr *)&spn, sizeof(spn)); + /* normal I/O here ... */ + close(fd); + + +.. Warning: + + When polling a connected pipe socket for writability, there is an + intrinsic race condition whereby writability might be lost between the + polling and the writing system calls. In this case, the socket will + block until write becomes possible again, unless non-blocking mode + is enabled. + + +The pipe protocol provides two socket options at the SOL_PNPIPE level: + + PNPIPE_ENCAP accepts one integer value (int) of: + + PNPIPE_ENCAP_NONE: + The socket operates normally (default). + + PNPIPE_ENCAP_IP: + The socket is used as a backend for a virtual IP + interface. This requires CAP_NET_ADMIN capability. GPRS data + support on Nokia modems can use this. Note that the socket cannot + be reliably poll()'d or read() from while in this mode. + + PNPIPE_IFINDEX + is a read-only integer value. It contains the + interface index of the network interface created by PNPIPE_ENCAP, + or zero if encapsulation is off. + + PNPIPE_HANDLE + is a read-only integer value. It contains the underlying + identifier ("pipe handle") of the pipe. This is only defined for + socket descriptors that are already connected or being connected. + + +Authors +------- + +Linux Phonet was initially written by Sakari Ailus. + +Other contributors include Mikä Liljeberg, Andras Domokos, +Carlos Chinea and Rémi Denis-Courmont. + +Copyright |copy| 2008 Nokia Corporation. diff --git a/Documentation/networking/phy.rst b/Documentation/networking/phy.rst new file mode 100644 index 0000000000..1283240d76 --- /dev/null +++ b/Documentation/networking/phy.rst @@ -0,0 +1,551 @@ +===================== +PHY Abstraction Layer +===================== + +Purpose +======= + +Most network devices consist of set of registers which provide an interface +to a MAC layer, which communicates with the physical connection through a +PHY. The PHY concerns itself with negotiating link parameters with the link +partner on the other side of the network connection (typically, an ethernet +cable), and provides a register interface to allow drivers to determine what +settings were chosen, and to configure what settings are allowed. + +While these devices are distinct from the network devices, and conform to a +standard layout for the registers, it has been common practice to integrate +the PHY management code with the network driver. This has resulted in large +amounts of redundant code. Also, on embedded systems with multiple (and +sometimes quite different) ethernet controllers connected to the same +management bus, it is difficult to ensure safe use of the bus. + +Since the PHYs are devices, and the management busses through which they are +accessed are, in fact, busses, the PHY Abstraction Layer treats them as such. +In doing so, it has these goals: + +#. Increase code-reuse +#. Increase overall code-maintainability +#. Speed development time for new network drivers, and for new systems + +Basically, this layer is meant to provide an interface to PHY devices which +allows network driver writers to write as little code as possible, while +still providing a full feature set. + +The MDIO bus +============ + +Most network devices are connected to a PHY by means of a management bus. +Different devices use different busses (though some share common interfaces). +In order to take advantage of the PAL, each bus interface needs to be +registered as a distinct device. + +#. read and write functions must be implemented. Their prototypes are:: + + int write(struct mii_bus *bus, int mii_id, int regnum, u16 value); + int read(struct mii_bus *bus, int mii_id, int regnum); + + mii_id is the address on the bus for the PHY, and regnum is the register + number. These functions are guaranteed not to be called from interrupt + time, so it is safe for them to block, waiting for an interrupt to signal + the operation is complete + +#. A reset function is optional. This is used to return the bus to an + initialized state. + +#. A probe function is needed. This function should set up anything the bus + driver needs, setup the mii_bus structure, and register with the PAL using + mdiobus_register. Similarly, there's a remove function to undo all of + that (use mdiobus_unregister). + +#. Like any driver, the device_driver structure must be configured, and init + exit functions are used to register the driver. + +#. The bus must also be declared somewhere as a device, and registered. + +As an example for how one driver implemented an mdio bus driver, see +drivers/net/ethernet/freescale/fsl_pq_mdio.c and an associated DTS file +for one of the users. (e.g. "git grep fsl,.*-mdio arch/powerpc/boot/dts/") + +(RG)MII/electrical interface considerations +=========================================== + +The Reduced Gigabit Medium Independent Interface (RGMII) is a 12-pin +electrical signal interface using a synchronous 125Mhz clock signal and several +data lines. Due to this design decision, a 1.5ns to 2ns delay must be added +between the clock line (RXC or TXC) and the data lines to let the PHY (clock +sink) have a large enough setup and hold time to sample the data lines correctly. The +PHY library offers different types of PHY_INTERFACE_MODE_RGMII* values to let +the PHY driver and optionally the MAC driver, implement the required delay. The +values of phy_interface_t must be understood from the perspective of the PHY +device itself, leading to the following: + +* PHY_INTERFACE_MODE_RGMII: the PHY is not responsible for inserting any + internal delay by itself, it assumes that either the Ethernet MAC (if capable) + or the PCB traces insert the correct 1.5-2ns delay + +* PHY_INTERFACE_MODE_RGMII_TXID: the PHY should insert an internal delay + for the transmit data lines (TXD[3:0]) processed by the PHY device + +* PHY_INTERFACE_MODE_RGMII_RXID: the PHY should insert an internal delay + for the receive data lines (RXD[3:0]) processed by the PHY device + +* PHY_INTERFACE_MODE_RGMII_ID: the PHY should insert internal delays for + both transmit AND receive data lines from/to the PHY device + +Whenever possible, use the PHY side RGMII delay for these reasons: + +* PHY devices may offer sub-nanosecond granularity in how they allow a + receiver/transmitter side delay (e.g: 0.5, 1.0, 1.5ns) to be specified. Such + precision may be required to account for differences in PCB trace lengths + +* PHY devices are typically qualified for a large range of applications + (industrial, medical, automotive...), and they provide a constant and + reliable delay across temperature/pressure/voltage ranges + +* PHY device drivers in PHYLIB being reusable by nature, being able to + configure correctly a specified delay enables more designs with similar delay + requirements to be operated correctly + +For cases where the PHY is not capable of providing this delay, but the +Ethernet MAC driver is capable of doing so, the correct phy_interface_t value +should be PHY_INTERFACE_MODE_RGMII, and the Ethernet MAC driver should be +configured correctly in order to provide the required transmit and/or receive +side delay from the perspective of the PHY device. Conversely, if the Ethernet +MAC driver looks at the phy_interface_t value, for any other mode but +PHY_INTERFACE_MODE_RGMII, it should make sure that the MAC-level delays are +disabled. + +In case neither the Ethernet MAC, nor the PHY are capable of providing the +required delays, as defined per the RGMII standard, several options may be +available: + +* Some SoCs may offer a pin pad/mux/controller capable of configuring a given + set of pins' strength, delays, and voltage; and it may be a suitable + option to insert the expected 2ns RGMII delay. + +* Modifying the PCB design to include a fixed delay (e.g: using a specifically + designed serpentine), which may not require software configuration at all. + +Common problems with RGMII delay mismatch +----------------------------------------- + +When there is a RGMII delay mismatch between the Ethernet MAC and the PHY, this +will most likely result in the clock and data line signals to be unstable when +the PHY or MAC take a snapshot of these signals to translate them into logical +1 or 0 states and reconstruct the data being transmitted/received. Typical +symptoms include: + +* Transmission/reception partially works, and there is frequent or occasional + packet loss observed + +* Ethernet MAC may report some or all packets ingressing with a FCS/CRC error, + or just discard them all + +* Switching to lower speeds such as 10/100Mbits/sec makes the problem go away + (since there is enough setup/hold time in that case) + +Connecting to a PHY +=================== + +Sometime during startup, the network driver needs to establish a connection +between the PHY device, and the network device. At this time, the PHY's bus +and drivers need to all have been loaded, so it is ready for the connection. +At this point, there are several ways to connect to the PHY: + +#. The PAL handles everything, and only calls the network driver when + the link state changes, so it can react. + +#. The PAL handles everything except interrupts (usually because the + controller has the interrupt registers). + +#. The PAL handles everything, but checks in with the driver every second, + allowing the network driver to react first to any changes before the PAL + does. + +#. The PAL serves only as a library of functions, with the network device + manually calling functions to update status, and configure the PHY + + +Letting the PHY Abstraction Layer do Everything +=============================================== + +If you choose option 1 (The hope is that every driver can, but to still be +useful to drivers that can't), connecting to the PHY is simple: + +First, you need a function to react to changes in the link state. This +function follows this protocol:: + + static void adjust_link(struct net_device *dev); + +Next, you need to know the device name of the PHY connected to this device. +The name will look something like, "0:00", where the first number is the +bus id, and the second is the PHY's address on that bus. Typically, +the bus is responsible for making its ID unique. + +Now, to connect, just call this function:: + + phydev = phy_connect(dev, phy_name, &adjust_link, interface); + +*phydev* is a pointer to the phy_device structure which represents the PHY. +If phy_connect is successful, it will return the pointer. dev, here, is the +pointer to your net_device. Once done, this function will have started the +PHY's software state machine, and registered for the PHY's interrupt, if it +has one. The phydev structure will be populated with information about the +current state, though the PHY will not yet be truly operational at this +point. + +PHY-specific flags should be set in phydev->dev_flags prior to the call +to phy_connect() such that the underlying PHY driver can check for flags +and perform specific operations based on them. +This is useful if the system has put hardware restrictions on +the PHY/controller, of which the PHY needs to be aware. + +*interface* is a u32 which specifies the connection type used +between the controller and the PHY. Examples are GMII, MII, +RGMII, and SGMII. See "PHY interface mode" below. For a full +list, see include/linux/phy.h + +Now just make sure that phydev->supported and phydev->advertising have any +values pruned from them which don't make sense for your controller (a 10/100 +controller may be connected to a gigabit capable PHY, so you would need to +mask off SUPPORTED_1000baseT*). See include/linux/ethtool.h for definitions +for these bitfields. Note that you should not SET any bits, except the +SUPPORTED_Pause and SUPPORTED_AsymPause bits (see below), or the PHY may get +put into an unsupported state. + +Lastly, once the controller is ready to handle network traffic, you call +phy_start(phydev). This tells the PAL that you are ready, and configures the +PHY to connect to the network. If the MAC interrupt of your network driver +also handles PHY status changes, just set phydev->irq to PHY_MAC_INTERRUPT +before you call phy_start and use phy_mac_interrupt() from the network +driver. If you don't want to use interrupts, set phydev->irq to PHY_POLL. +phy_start() enables the PHY interrupts (if applicable) and starts the +phylib state machine. + +When you want to disconnect from the network (even if just briefly), you call +phy_stop(phydev). This function also stops the phylib state machine and +disables PHY interrupts. + +PHY interface modes +=================== + +The PHY interface mode supplied in the phy_connect() family of functions +defines the initial operating mode of the PHY interface. This is not +guaranteed to remain constant; there are PHYs which dynamically change +their interface mode without software interaction depending on the +negotiation results. + +Some of the interface modes are described below: + +``PHY_INTERFACE_MODE_SMII`` + This is serial MII, clocked at 125MHz, supporting 100M and 10M speeds. + Some details can be found in + https://opencores.org/ocsvn/smii/smii/trunk/doc/SMII.pdf + +``PHY_INTERFACE_MODE_1000BASEX`` + This defines the 1000BASE-X single-lane serdes link as defined by the + 802.3 standard section 36. The link operates at a fixed bit rate of + 1.25Gbaud using a 10B/8B encoding scheme, resulting in an underlying + data rate of 1Gbps. Embedded in the data stream is a 16-bit control + word which is used to negotiate the duplex and pause modes with the + remote end. This does not include "up-clocked" variants such as 2.5Gbps + speeds (see below.) + +``PHY_INTERFACE_MODE_2500BASEX`` + This defines a variant of 1000BASE-X which is clocked 2.5 times as fast + as the 802.3 standard, giving a fixed bit rate of 3.125Gbaud. + +``PHY_INTERFACE_MODE_SGMII`` + This is used for Cisco SGMII, which is a modification of 1000BASE-X + as defined by the 802.3 standard. The SGMII link consists of a single + serdes lane running at a fixed bit rate of 1.25Gbaud with 10B/8B + encoding. The underlying data rate is 1Gbps, with the slower speeds of + 100Mbps and 10Mbps being achieved through replication of each data symbol. + The 802.3 control word is re-purposed to send the negotiated speed and + duplex information from to the MAC, and for the MAC to acknowledge + receipt. This does not include "up-clocked" variants such as 2.5Gbps + speeds. + + Note: mismatched SGMII vs 1000BASE-X configuration on a link can + successfully pass data in some circumstances, but the 16-bit control + word will not be correctly interpreted, which may cause mismatches in + duplex, pause or other settings. This is dependent on the MAC and/or + PHY behaviour. + +``PHY_INTERFACE_MODE_5GBASER`` + This is the IEEE 802.3 Clause 129 defined 5GBASE-R protocol. It is + identical to the 10GBASE-R protocol defined in Clause 49, with the + exception that it operates at half the frequency. Please refer to the + IEEE standard for the definition. + +``PHY_INTERFACE_MODE_10GBASER`` + This is the IEEE 802.3 Clause 49 defined 10GBASE-R protocol used with + various different mediums. Please refer to the IEEE standard for a + definition of this. + + Note: 10GBASE-R is just one protocol that can be used with XFI and SFI. + XFI and SFI permit multiple protocols over a single SERDES lane, and + also defines the electrical characteristics of the signals with a host + compliance board plugged into the host XFP/SFP connector. Therefore, + XFI and SFI are not PHY interface types in their own right. + +``PHY_INTERFACE_MODE_10GKR`` + This is the IEEE 802.3 Clause 49 defined 10GBASE-R with Clause 73 + autonegotiation. Please refer to the IEEE standard for further + information. + + Note: due to legacy usage, some 10GBASE-R usage incorrectly makes + use of this definition. + +``PHY_INTERFACE_MODE_25GBASER`` + This is the IEEE 802.3 PCS Clause 107 defined 25GBASE-R protocol. + The PCS is identical to 10GBASE-R, i.e. 64B/66B encoded + running 2.5 as fast, giving a fixed bit rate of 25.78125 Gbaud. + Please refer to the IEEE standard for further information. + +``PHY_INTERFACE_MODE_100BASEX`` + This defines IEEE 802.3 Clause 24. The link operates at a fixed data + rate of 125Mpbs using a 4B/5B encoding scheme, resulting in an underlying + data rate of 100Mpbs. + +``PHY_INTERFACE_MODE_QUSGMII`` + This defines the Cisco the Quad USGMII mode, which is the Quad variant of + the USGMII (Universal SGMII) link. It's very similar to QSGMII, but uses + a Packet Control Header (PCH) instead of the 7 bytes preamble to carry not + only the port id, but also so-called "extensions". The only documented + extension so-far in the specification is the inclusion of timestamps, for + PTP-enabled PHYs. This mode isn't compatible with QSGMII, but offers the + same capabilities in terms of link speed and negotiation. + +``PHY_INTERFACE_MODE_1000BASEKX`` + This is 1000BASE-X as defined by IEEE 802.3 Clause 36 with Clause 73 + autonegotiation. Generally, it will be used with a Clause 70 PMD. To + contrast with the 1000BASE-X phy mode used for Clause 38 and 39 PMDs, this + interface mode has different autonegotiation and only supports full duplex. + +``PHY_INTERFACE_MODE_PSGMII`` + This is the Penta SGMII mode, it is similar to QSGMII but it combines 5 + SGMII lines into a single link compared to 4 on QSGMII. + +Pause frames / flow control +=========================== + +The PHY does not participate directly in flow control/pause frames except by +making sure that the SUPPORTED_Pause and SUPPORTED_AsymPause bits are set in +MII_ADVERTISE to indicate towards the link partner that the Ethernet MAC +controller supports such a thing. Since flow control/pause frames generation +involves the Ethernet MAC driver, it is recommended that this driver takes care +of properly indicating advertisement and support for such features by setting +the SUPPORTED_Pause and SUPPORTED_AsymPause bits accordingly. This can be done +either before or after phy_connect() and/or as a result of implementing the +ethtool::set_pauseparam feature. + + +Keeping Close Tabs on the PAL +============================= + +It is possible that the PAL's built-in state machine needs a little help to +keep your network device and the PHY properly in sync. If so, you can +register a helper function when connecting to the PHY, which will be called +every second before the state machine reacts to any changes. To do this, you +need to manually call phy_attach() and phy_prepare_link(), and then call +phy_start_machine() with the second argument set to point to your special +handler. + +Currently there are no examples of how to use this functionality, and testing +on it has been limited because the author does not have any drivers which use +it (they all use option 1). So Caveat Emptor. + +Doing it all yourself +===================== + +There's a remote chance that the PAL's built-in state machine cannot track +the complex interactions between the PHY and your network device. If this is +so, you can simply call phy_attach(), and not call phy_start_machine or +phy_prepare_link(). This will mean that phydev->state is entirely yours to +handle (phy_start and phy_stop toggle between some of the states, so you +might need to avoid them). + +An effort has been made to make sure that useful functionality can be +accessed without the state-machine running, and most of these functions are +descended from functions which did not interact with a complex state-machine. +However, again, no effort has been made so far to test running without the +state machine, so tryer beware. + +Here is a brief rundown of the functions:: + + int phy_read(struct phy_device *phydev, u16 regnum); + int phy_write(struct phy_device *phydev, u16 regnum, u16 val); + +Simple read/write primitives. They invoke the bus's read/write function +pointers. +:: + + void phy_print_status(struct phy_device *phydev); + +A convenience function to print out the PHY status neatly. +:: + + void phy_request_interrupt(struct phy_device *phydev); + +Requests the IRQ for the PHY interrupts. +:: + + struct phy_device * phy_attach(struct net_device *dev, const char *phy_id, + phy_interface_t interface); + +Attaches a network device to a particular PHY, binding the PHY to a generic +driver if none was found during bus initialization. +:: + + int phy_start_aneg(struct phy_device *phydev); + +Using variables inside the phydev structure, either configures advertising +and resets autonegotiation, or disables autonegotiation, and configures +forced settings. +:: + + static inline int phy_read_status(struct phy_device *phydev); + +Fills the phydev structure with up-to-date information about the current +settings in the PHY. +:: + + int phy_ethtool_ksettings_set(struct phy_device *phydev, + const struct ethtool_link_ksettings *cmd); + +Ethtool convenience functions. +:: + + int phy_mii_ioctl(struct phy_device *phydev, + struct mii_ioctl_data *mii_data, int cmd); + +The MII ioctl. Note that this function will completely screw up the state +machine if you write registers like BMCR, BMSR, ADVERTISE, etc. Best to +use this only to write registers which are not standard, and don't set off +a renegotiation. + +PHY Device Drivers +================== + +With the PHY Abstraction Layer, adding support for new PHYs is +quite easy. In some cases, no work is required at all! However, +many PHYs require a little hand-holding to get up-and-running. + +Generic PHY driver +------------------ + +If the desired PHY doesn't have any errata, quirks, or special +features you want to support, then it may be best to not add +support, and let the PHY Abstraction Layer's Generic PHY Driver +do all of the work. + +Writing a PHY driver +-------------------- + +If you do need to write a PHY driver, the first thing to do is +make sure it can be matched with an appropriate PHY device. +This is done during bus initialization by reading the device's +UID (stored in registers 2 and 3), then comparing it to each +driver's phy_id field by ANDing it with each driver's +phy_id_mask field. Also, it needs a name. Here's an example:: + + static struct phy_driver dm9161_driver = { + .phy_id = 0x0181b880, + .name = "Davicom DM9161E", + .phy_id_mask = 0x0ffffff0, + ... + } + +Next, you need to specify what features (speed, duplex, autoneg, +etc) your PHY device and driver support. Most PHYs support +PHY_BASIC_FEATURES, but you can look in include/mii.h for other +features. + +Each driver consists of a number of function pointers, documented +in include/linux/phy.h under the phy_driver structure. + +Of these, only config_aneg and read_status are required to be +assigned by the driver code. The rest are optional. Also, it is +preferred to use the generic phy driver's versions of these two +functions if at all possible: genphy_read_status and +genphy_config_aneg. If this is not possible, it is likely that +you only need to perform some actions before and after invoking +these functions, and so your functions will wrap the generic +ones. + +Feel free to look at the Marvell, Cicada, and Davicom drivers in +drivers/net/phy/ for examples (the lxt and qsemi drivers have +not been tested as of this writing). + +The PHY's MMD register accesses are handled by the PAL framework +by default, but can be overridden by a specific PHY driver if +required. This could be the case if a PHY was released for +manufacturing before the MMD PHY register definitions were +standardized by the IEEE. Most modern PHYs will be able to use +the generic PAL framework for accessing the PHY's MMD registers. +An example of such usage is for Energy Efficient Ethernet support, +implemented in the PAL. This support uses the PAL to access MMD +registers for EEE query and configuration if the PHY supports +the IEEE standard access mechanisms, or can use the PHY's specific +access interfaces if overridden by the specific PHY driver. See +the Micrel driver in drivers/net/phy/ for an example of how this +can be implemented. + +Board Fixups +============ + +Sometimes the specific interaction between the platform and the PHY requires +special handling. For instance, to change where the PHY's clock input is, +or to add a delay to account for latency issues in the data path. In order +to support such contingencies, the PHY Layer allows platform code to register +fixups to be run when the PHY is brought up (or subsequently reset). + +When the PHY Layer brings up a PHY it checks to see if there are any fixups +registered for it, matching based on UID (contained in the PHY device's phy_id +field) and the bus identifier (contained in phydev->dev.bus_id). Both must +match, however two constants, PHY_ANY_ID and PHY_ANY_UID, are provided as +wildcards for the bus ID and UID, respectively. + +When a match is found, the PHY layer will invoke the run function associated +with the fixup. This function is passed a pointer to the phy_device of +interest. It should therefore only operate on that PHY. + +The platform code can either register the fixup using phy_register_fixup():: + + int phy_register_fixup(const char *phy_id, + u32 phy_uid, u32 phy_uid_mask, + int (*run)(struct phy_device *)); + +Or using one of the two stubs, phy_register_fixup_for_uid() and +phy_register_fixup_for_id():: + + int phy_register_fixup_for_uid(u32 phy_uid, u32 phy_uid_mask, + int (*run)(struct phy_device *)); + int phy_register_fixup_for_id(const char *phy_id, + int (*run)(struct phy_device *)); + +The stubs set one of the two matching criteria, and set the other one to +match anything. + +When phy_register_fixup() or \*_for_uid()/\*_for_id() is called at module load +time, the module needs to unregister the fixup and free allocated memory when +it's unloaded. + +Call one of following function before unloading module:: + + int phy_unregister_fixup(const char *phy_id, u32 phy_uid, u32 phy_uid_mask); + int phy_unregister_fixup_for_uid(u32 phy_uid, u32 phy_uid_mask); + int phy_register_fixup_for_id(const char *phy_id); + +Standards +========= + +IEEE Standard 802.3: CSMA/CD Access Method and Physical Layer Specifications, Section Two: +http://standards.ieee.org/getieee802/download/802.3-2008_section2.pdf + +RGMII v1.3: +http://web.archive.org/web/20160303212629/http://www.hp.com/rnd/pdfs/RGMIIv1_3.pdf + +RGMII v2.0: +http://web.archive.org/web/20160303171328/http://www.hp.com/rnd/pdfs/RGMIIv2_0_final_hp.pdf diff --git a/Documentation/networking/pktgen.rst b/Documentation/networking/pktgen.rst new file mode 100644 index 0000000000..1225f0f63f --- /dev/null +++ b/Documentation/networking/pktgen.rst @@ -0,0 +1,410 @@ +.. SPDX-License-Identifier: GPL-2.0 + +==================================== +HOWTO for the linux packet generator +==================================== + +Enable CONFIG_NET_PKTGEN to compile and build pktgen either in-kernel +or as a module. A module is preferred; modprobe pktgen if needed. Once +running, pktgen creates a thread for each CPU with affinity to that CPU. +Monitoring and controlling is done via /proc. It is easiest to select a +suitable sample script and configure that. + +On a dual CPU:: + + ps aux | grep pkt + root 129 0.3 0.0 0 0 ? SW 2003 523:20 [kpktgend_0] + root 130 0.3 0.0 0 0 ? SW 2003 509:50 [kpktgend_1] + + +For monitoring and control pktgen creates:: + + /proc/net/pktgen/pgctrl + /proc/net/pktgen/kpktgend_X + /proc/net/pktgen/ethX + + +Tuning NIC for max performance +============================== + +The default NIC settings are (likely) not tuned for pktgen's artificial +overload type of benchmarking, as this could hurt the normal use-case. + +Specifically increasing the TX ring buffer in the NIC:: + + # ethtool -G ethX tx 1024 + +A larger TX ring can improve pktgen's performance, while it can hurt +in the general case, 1) because the TX ring buffer might get larger +than the CPU's L1/L2 cache, 2) because it allows more queueing in the +NIC HW layer (which is bad for bufferbloat). + +One should hesitate to conclude that packets/descriptors in the HW +TX ring cause delay. Drivers usually delay cleaning up the +ring-buffers for various performance reasons, and packets stalling +the TX ring might just be waiting for cleanup. + +This cleanup issue is specifically the case for the driver ixgbe +(Intel 82599 chip). This driver (ixgbe) combines TX+RX ring cleanups, +and the cleanup interval is affected by the ethtool --coalesce setting +of parameter "rx-usecs". + +For ixgbe use e.g. "30" resulting in approx 33K interrupts/sec (1/30*10^6):: + + # ethtool -C ethX rx-usecs 30 + + +Kernel threads +============== +Pktgen creates a thread for each CPU with affinity to that CPU. +Which is controlled through procfile /proc/net/pktgen/kpktgend_X. + +Example: /proc/net/pktgen/kpktgend_0:: + + Running: + Stopped: eth4@0 + Result: OK: add_device=eth4@0 + +Most important are the devices assigned to the thread. + +The two basic thread commands are: + + * add_device DEVICE@NAME -- adds a single device + * rem_device_all -- remove all associated devices + +When adding a device to a thread, a corresponding procfile is created +which is used for configuring this device. Thus, device names need to +be unique. + +To support adding the same device to multiple threads, which is useful +with multi queue NICs, the device naming scheme is extended with "@": +device@something + +The part after "@" can be anything, but it is custom to use the thread +number. + +Viewing devices +=============== + +The Params section holds configured information. The Current section +holds running statistics. The Result is printed after a run or after +interruption. Example:: + + /proc/net/pktgen/eth4@0 + + Params: count 100000 min_pkt_size: 60 max_pkt_size: 60 + frags: 0 delay: 0 clone_skb: 64 ifname: eth4@0 + flows: 0 flowlen: 0 + queue_map_min: 0 queue_map_max: 0 + dst_min: 192.168.81.2 dst_max: + src_min: src_max: + src_mac: 90:e2:ba:0a:56:b4 dst_mac: 00:1b:21:3c:9d:f8 + udp_src_min: 9 udp_src_max: 109 udp_dst_min: 9 udp_dst_max: 9 + src_mac_count: 0 dst_mac_count: 0 + Flags: UDPSRC_RND NO_TIMESTAMP QUEUE_MAP_CPU + Current: + pkts-sofar: 100000 errors: 0 + started: 623913381008us stopped: 623913396439us idle: 25us + seq_num: 100001 cur_dst_mac_offset: 0 cur_src_mac_offset: 0 + cur_saddr: 192.168.8.3 cur_daddr: 192.168.81.2 + cur_udp_dst: 9 cur_udp_src: 42 + cur_queue_map: 0 + flows: 0 + Result: OK: 15430(c15405+d25) usec, 100000 (60byte,0frags) + 6480562pps 3110Mb/sec (3110669760bps) errors: 0 + + +Configuring devices +=================== +This is done via the /proc interface, and most easily done via pgset +as defined in the sample scripts. +You need to specify PGDEV environment variable to use functions from sample +scripts, i.e.:: + + export PGDEV=/proc/net/pktgen/eth4@0 + source samples/pktgen/functions.sh + +Examples:: + + pg_ctrl start starts injection. + pg_ctrl stop aborts injection. Also, ^C aborts generator. + + pgset "clone_skb 1" sets the number of copies of the same packet + pgset "clone_skb 0" use single SKB for all transmits + pgset "burst 8" uses xmit_more API to queue 8 copies of the same + packet and update HW tx queue tail pointer once. + "burst 1" is the default + pgset "pkt_size 9014" sets packet size to 9014 + pgset "frags 5" packet will consist of 5 fragments + pgset "count 200000" sets number of packets to send, set to zero + for continuous sends until explicitly stopped. + + pgset "delay 5000" adds delay to hard_start_xmit(). nanoseconds + + pgset "dst 10.0.0.1" sets IP destination address + (BEWARE! This generator is very aggressive!) + + pgset "dst_min 10.0.0.1" Same as dst + pgset "dst_max 10.0.0.254" Set the maximum destination IP. + pgset "src_min 10.0.0.1" Set the minimum (or only) source IP. + pgset "src_max 10.0.0.254" Set the maximum source IP. + pgset "dst6 fec0::1" IPV6 destination address + pgset "src6 fec0::2" IPV6 source address + pgset "dstmac 00:00:00:00:00:00" sets MAC destination address + pgset "srcmac 00:00:00:00:00:00" sets MAC source address + + pgset "queue_map_min 0" Sets the min value of tx queue interval + pgset "queue_map_max 7" Sets the max value of tx queue interval, for multiqueue devices + To select queue 1 of a given device, + use queue_map_min=1 and queue_map_max=1 + + pgset "src_mac_count 1" Sets the number of MACs we'll range through. + The 'minimum' MAC is what you set with srcmac. + + pgset "dst_mac_count 1" Sets the number of MACs we'll range through. + The 'minimum' MAC is what you set with dstmac. + + pgset "flag [name]" Set a flag to determine behaviour. Current flags + are: IPSRC_RND # IP source is random (between min/max) + IPDST_RND # IP destination is random + UDPSRC_RND, UDPDST_RND, + MACSRC_RND, MACDST_RND + TXSIZE_RND, IPV6, + MPLS_RND, VID_RND, SVID_RND + FLOW_SEQ, + QUEUE_MAP_RND # queue map random + QUEUE_MAP_CPU # queue map mirrors smp_processor_id() + UDPCSUM, + IPSEC # IPsec encapsulation (needs CONFIG_XFRM) + NODE_ALLOC # node specific memory allocation + NO_TIMESTAMP # disable timestamping + pgset 'flag ![name]' Clear a flag to determine behaviour. + Note that you might need to use single quote in + interactive mode, so that your shell wouldn't expand + the specified flag as a history command. + + pgset "spi [SPI_VALUE]" Set specific SA used to transform packet. + + pgset "udp_src_min 9" set UDP source port min, If < udp_src_max, then + cycle through the port range. + + pgset "udp_src_max 9" set UDP source port max. + pgset "udp_dst_min 9" set UDP destination port min, If < udp_dst_max, then + cycle through the port range. + pgset "udp_dst_max 9" set UDP destination port max. + + pgset "mpls 0001000a,0002000a,0000000a" set MPLS labels (in this example + outer label=16,middle label=32, + inner label=0 (IPv4 NULL)) Note that + there must be no spaces between the + arguments. Leading zeros are required. + Do not set the bottom of stack bit, + that's done automatically. If you do + set the bottom of stack bit, that + indicates that you want to randomly + generate that address and the flag + MPLS_RND will be turned on. You + can have any mix of random and fixed + labels in the label stack. + + pgset "mpls 0" turn off mpls (or any invalid argument works too!) + + pgset "vlan_id 77" set VLAN ID 0-4095 + pgset "vlan_p 3" set priority bit 0-7 (default 0) + pgset "vlan_cfi 0" set canonical format identifier 0-1 (default 0) + + pgset "svlan_id 22" set SVLAN ID 0-4095 + pgset "svlan_p 3" set priority bit 0-7 (default 0) + pgset "svlan_cfi 0" set canonical format identifier 0-1 (default 0) + + pgset "vlan_id 9999" > 4095 remove vlan and svlan tags + pgset "svlan 9999" > 4095 remove svlan tag + + + pgset "tos XX" set former IPv4 TOS field (e.g. "tos 28" for AF11 no ECN, default 00) + pgset "traffic_class XX" set former IPv6 TRAFFIC CLASS (e.g. "traffic_class B8" for EF no ECN, default 00) + + pgset "rate 300M" set rate to 300 Mb/s + pgset "ratep 1000000" set rate to 1Mpps + + pgset "xmit_mode netif_receive" RX inject into stack netif_receive_skb() + Works with "burst" but not with "clone_skb". + Default xmit_mode is "start_xmit". + +Sample scripts +============== + +A collection of tutorial scripts and helpers for pktgen is in the +samples/pktgen directory. The helper parameters.sh file support easy +and consistent parameter parsing across the sample scripts. + +Usage example and help:: + + ./pktgen_sample01_simple.sh -i eth4 -m 00:1B:21:3C:9D:F8 -d 192.168.8.2 + +Usage::: + + ./pktgen_sample01_simple.sh [-vx] -i ethX + + -i : ($DEV) output interface/device (required) + -s : ($PKT_SIZE) packet size + -d : ($DEST_IP) destination IP. CIDR (e.g. 198.18.0.0/15) is also allowed + -m : ($DST_MAC) destination MAC-addr + -p : ($DST_PORT) destination PORT range (e.g. 433-444) is also allowed + -t : ($THREADS) threads to start + -f : ($F_THREAD) index of first thread (zero indexed CPU number) + -c : ($SKB_CLONE) SKB clones send before alloc new SKB + -n : ($COUNT) num messages to send per thread, 0 means indefinitely + -b : ($BURST) HW level bursting of SKBs + -v : ($VERBOSE) verbose + -x : ($DEBUG) debug + -6 : ($IP6) IPv6 + -w : ($DELAY) Tx Delay value (ns) + -a : ($APPEND) Script will not reset generator's state, but will append its config + +The global variables being set are also listed. E.g. the required +interface/device parameter "-i" sets variable $DEV. Copy the +pktgen_sampleXX scripts and modify them to fit your own needs. + + +Interrupt affinity +=================== +Note that when adding devices to a specific CPU it is a good idea to +also assign /proc/irq/XX/smp_affinity so that the TX interrupts are bound +to the same CPU. This reduces cache bouncing when freeing skbs. + +Plus using the device flag QUEUE_MAP_CPU, which maps the SKBs TX queue +to the running threads CPU (directly from smp_processor_id()). + +Enable IPsec +============ +Default IPsec transformation with ESP encapsulation plus transport mode +can be enabled by simply setting:: + + pgset "flag IPSEC" + pgset "flows 1" + +To avoid breaking existing testbed scripts for using AH type and tunnel mode, +you can use "pgset spi SPI_VALUE" to specify which transformation mode +to employ. + + +Current commands and configuration options +========================================== + +**Pgcontrol commands**:: + + start + stop + reset + +**Thread commands**:: + + add_device + rem_device_all + + +**Device commands**:: + + count + clone_skb + burst + debug + + frags + delay + + src_mac_count + dst_mac_count + + pkt_size + min_pkt_size + max_pkt_size + + queue_map_min + queue_map_max + skb_priority + + tos (ipv4) + traffic_class (ipv6) + + mpls + + udp_src_min + udp_src_max + + udp_dst_min + udp_dst_max + + node + + flag + IPSRC_RND + IPDST_RND + UDPSRC_RND + UDPDST_RND + MACSRC_RND + MACDST_RND + TXSIZE_RND + IPV6 + MPLS_RND + VID_RND + SVID_RND + FLOW_SEQ + QUEUE_MAP_RND + QUEUE_MAP_CPU + UDPCSUM + IPSEC + NODE_ALLOC + NO_TIMESTAMP + + spi (ipsec) + + dst_min + dst_max + + src_min + src_max + + dst_mac + src_mac + + clear_counters + + src6 + dst6 + dst6_max + dst6_min + + flows + flowlen + + rate + ratep + + xmit_mode <start_xmit|netif_receive> + + vlan_cfi + vlan_id + vlan_p + + svlan_cfi + svlan_id + svlan_p + + +References: + +- ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/ +- ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/examples/ + +Paper from Linux-Kongress in Erlangen 2004. +- ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/pktgen_paper.pdf + +Thanks to: + +Grant Grundler for testing on IA-64 and parisc, Harald Welte, Lennert Buytenhek +Stephen Hemminger, Andi Kleen, Dave Miller and many others. + + +Good luck with the linux net-development. diff --git a/Documentation/networking/plip.rst b/Documentation/networking/plip.rst new file mode 100644 index 0000000000..0eda745050 --- /dev/null +++ b/Documentation/networking/plip.rst @@ -0,0 +1,222 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================================================ +PLIP: The Parallel Line Internet Protocol Device +================================================ + +Donald Becker (becker@super.org) +I.D.A. Supercomputing Research Center, Bowie MD 20715 + +At some point T. Thorn will probably contribute text, +Tommy Thorn (tthorn@daimi.aau.dk) + +PLIP Introduction +----------------- + +This document describes the parallel port packet pusher for Net/LGX. +This device interface allows a point-to-point connection between two +parallel ports to appear as a IP network interface. + +What is PLIP? +============= + +PLIP is Parallel Line IP, that is, the transportation of IP packages +over a parallel port. In the case of a PC, the obvious choice is the +printer port. PLIP is a non-standard, but [can use] uses the standard +LapLink null-printer cable [can also work in turbo mode, with a PLIP +cable]. [The protocol used to pack IP packages, is a simple one +initiated by Crynwr.] + +Advantages of PLIP +================== + +It's cheap, it's available everywhere, and it's easy. + +The PLIP cable is all that's needed to connect two Linux boxes, and it +can be built for very few bucks. + +Connecting two Linux boxes takes only a second's decision and a few +minutes' work, no need to search for a [supported] netcard. This might +even be especially important in the case of notebooks, where netcards +are not easily available. + +Not requiring a netcard also means that apart from connecting the +cables, everything else is software configuration [which in principle +could be made very easy.] + +Disadvantages of PLIP +===================== + +Doesn't work over a modem, like SLIP and PPP. Limited range, 15 m. +Can only be used to connect three (?) Linux boxes. Doesn't connect to +an existing Ethernet. Isn't standard (not even de facto standard, like +SLIP). + +Performance +=========== + +PLIP easily outperforms Ethernet cards....(ups, I was dreaming, but +it *is* getting late. EOB) + +PLIP driver details +------------------- + +The Linux PLIP driver is an implementation of the original Crynwr protocol, +that uses the parallel port subsystem of the kernel in order to properly +share parallel ports between PLIP and other services. + +IRQs and trigger timeouts +========================= + +When a parallel port used for a PLIP driver has an IRQ configured to it, the +PLIP driver is signaled whenever data is sent to it via the cable, such that +when no data is available, the driver isn't being used. + +However, on some machines it is hard, if not impossible, to configure an IRQ +to a certain parallel port, mainly because it is used by some other device. +On these machines, the PLIP driver can be used in IRQ-less mode, where +the PLIP driver would constantly poll the parallel port for data waiting, +and if such data is available, process it. This mode is less efficient than +the IRQ mode, because the driver has to check the parallel port many times +per second, even when no data at all is sent. Some rough measurements +indicate that there isn't a noticeable performance drop when using IRQ-less +mode as compared to IRQ mode as far as the data transfer speed is involved. +There is a performance drop on the machine hosting the driver. + +When the PLIP driver is used in IRQ mode, the timeout used for triggering a +data transfer (the maximal time the PLIP driver would allow the other side +before announcing a timeout, when trying to handshake a transfer of some +data) is, by default, 500usec. As IRQ delivery is more or less immediate, +this timeout is quite sufficient. + +When in IRQ-less mode, the PLIP driver polls the parallel port HZ times +per second (where HZ is typically 100 on most platforms, and 1024 on an +Alpha, as of this writing). Between two such polls, there are 10^6/HZ usecs. +On an i386, for example, 10^6/100 = 10000usec. It is easy to see that it is +quite possible for the trigger timeout to expire between two such polls, as +the timeout is only 500usec long. As a result, it is required to change the +trigger timeout on the *other* side of a PLIP connection, to about +10^6/HZ usecs. If both sides of a PLIP connection are used in IRQ-less mode, +this timeout is required on both sides. + +It appears that in practice, the trigger timeout can be shorter than in the +above calculation. It isn't an important issue, unless the wire is faulty, +in which case a long timeout would stall the machine when, for whatever +reason, bits are dropped. + +A utility that can perform this change in Linux is plipconfig, which is part +of the net-tools package (its location can be found in the +Documentation/Changes file). An example command would be +'plipconfig plipX trigger 10000', where plipX is the appropriate +PLIP device. + +PLIP hardware interconnection +----------------------------- + +PLIP uses several different data transfer methods. The first (and the +only one implemented in the early version of the code) uses a standard +printer "null" cable to transfer data four bits at a time using +data bit outputs connected to status bit inputs. + +The second data transfer method relies on both machines having +bi-directional parallel ports, rather than output-only ``printer`` +ports. This allows byte-wide transfers and avoids reconstructing +nibbles into bytes, leading to much faster transfers. + +Parallel Transfer Mode 0 Cable +============================== + +The cable for the first transfer mode is a standard +printer "null" cable which transfers data four bits at a time using +data bit outputs of the first port (machine T) connected to the +status bit inputs of the second port (machine R). There are five +status inputs, and they are used as four data inputs and a clock (data +strobe) input, arranged so that the data input bits appear as contiguous +bits with standard status register implementation. + +A cable that implements this protocol is available commercially as a +"Null Printer" or "Turbo Laplink" cable. It can be constructed with +two DB-25 male connectors symmetrically connected as follows:: + + STROBE output 1* + D0->ERROR 2 - 15 15 - 2 + D1->SLCT 3 - 13 13 - 3 + D2->PAPOUT 4 - 12 12 - 4 + D3->ACK 5 - 10 10 - 5 + D4->BUSY 6 - 11 11 - 6 + D5,D6,D7 are 7*, 8*, 9* + AUTOFD output 14* + INIT output 16* + SLCTIN 17 - 17 + extra grounds are 18*,19*,20*,21*,22*,23*,24* + GROUND 25 - 25 + + * Do not connect these pins on either end + +If the cable you are using has a metallic shield it should be +connected to the metallic DB-25 shell at one end only. + +Parallel Transfer Mode 1 +======================== + +The second data transfer method relies on both machines having +bi-directional parallel ports, rather than output-only ``printer`` +ports. This allows byte-wide transfers, and avoids reconstructing +nibbles into bytes. This cable should not be used on unidirectional +``printer`` (as opposed to ``parallel``) ports or when the machine +isn't configured for PLIP, as it will result in output driver +conflicts and the (unlikely) possibility of damage. + +The cable for this transfer mode should be constructed as follows:: + + STROBE->BUSY 1 - 11 + D0->D0 2 - 2 + D1->D1 3 - 3 + D2->D2 4 - 4 + D3->D3 5 - 5 + D4->D4 6 - 6 + D5->D5 7 - 7 + D6->D6 8 - 8 + D7->D7 9 - 9 + INIT -> ACK 16 - 10 + AUTOFD->PAPOUT 14 - 12 + SLCT->SLCTIN 13 - 17 + GND->ERROR 18 - 15 + extra grounds are 19*,20*,21*,22*,23*,24* + GROUND 25 - 25 + + * Do not connect these pins on either end + +Once again, if the cable you are using has a metallic shield it should +be connected to the metallic DB-25 shell at one end only. + +PLIP Mode 0 transfer protocol +============================= + +The PLIP driver is compatible with the "Crynwr" parallel port transfer +standard in Mode 0. That standard specifies the following protocol:: + + send header nibble '0x8' + count-low octet + count-high octet + ... data octets + checksum octet + +Each octet is sent as:: + + <wait for rx. '0x1?'> <send 0x10+(octet&0x0F)> + <wait for rx. '0x0?'> <send 0x00+((octet>>4)&0x0F)> + +To start a transfer the transmitting machine outputs a nibble 0x08. +That raises the ACK line, triggering an interrupt in the receiving +machine. The receiving machine disables interrupts and raises its own ACK +line. + +Restated:: + + (OUT is bit 0-4, OUT.j is bit j from OUT. IN likewise) + Send_Byte: + OUT := low nibble, OUT.4 := 1 + WAIT FOR IN.4 = 1 + OUT := high nibble, OUT.4 := 0 + WAIT FOR IN.4 = 0 diff --git a/Documentation/networking/ppp_generic.rst b/Documentation/networking/ppp_generic.rst new file mode 100644 index 0000000000..5a10abce59 --- /dev/null +++ b/Documentation/networking/ppp_generic.rst @@ -0,0 +1,456 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======================================== +PPP Generic Driver and Channel Interface +======================================== + + Paul Mackerras + paulus@samba.org + + 7 Feb 2002 + +The generic PPP driver in linux-2.4 provides an implementation of the +functionality which is of use in any PPP implementation, including: + +* the network interface unit (ppp0 etc.) +* the interface to the networking code +* PPP multilink: splitting datagrams between multiple links, and + ordering and combining received fragments +* the interface to pppd, via a /dev/ppp character device +* packet compression and decompression +* TCP/IP header compression and decompression +* detecting network traffic for demand dialling and for idle timeouts +* simple packet filtering + +For sending and receiving PPP frames, the generic PPP driver calls on +the services of PPP ``channels``. A PPP channel encapsulates a +mechanism for transporting PPP frames from one machine to another. A +PPP channel implementation can be arbitrarily complex internally but +has a very simple interface with the generic PPP code: it merely has +to be able to send PPP frames, receive PPP frames, and optionally +handle ioctl requests. Currently there are PPP channel +implementations for asynchronous serial ports, synchronous serial +ports, and for PPP over ethernet. + +This architecture makes it possible to implement PPP multilink in a +natural and straightforward way, by allowing more than one channel to +be linked to each ppp network interface unit. The generic layer is +responsible for splitting datagrams on transmit and recombining them +on receive. + + +PPP channel API +--------------- + +See include/linux/ppp_channel.h for the declaration of the types and +functions used to communicate between the generic PPP layer and PPP +channels. + +Each channel has to provide two functions to the generic PPP layer, +via the ppp_channel.ops pointer: + +* start_xmit() is called by the generic layer when it has a frame to + send. The channel has the option of rejecting the frame for + flow-control reasons. In this case, start_xmit() should return 0 + and the channel should call the ppp_output_wakeup() function at a + later time when it can accept frames again, and the generic layer + will then attempt to retransmit the rejected frame(s). If the frame + is accepted, the start_xmit() function should return 1. + +* ioctl() provides an interface which can be used by a user-space + program to control aspects of the channel's behaviour. This + procedure will be called when a user-space program does an ioctl + system call on an instance of /dev/ppp which is bound to the + channel. (Usually it would only be pppd which would do this.) + +The generic PPP layer provides seven functions to channels: + +* ppp_register_channel() is called when a channel has been created, to + notify the PPP generic layer of its presence. For example, setting + a serial port to the PPPDISC line discipline causes the ppp_async + channel code to call this function. + +* ppp_unregister_channel() is called when a channel is to be + destroyed. For example, the ppp_async channel code calls this when + a hangup is detected on the serial port. + +* ppp_output_wakeup() is called by a channel when it has previously + rejected a call to its start_xmit function, and can now accept more + packets. + +* ppp_input() is called by a channel when it has received a complete + PPP frame. + +* ppp_input_error() is called by a channel when it has detected that a + frame has been lost or dropped (for example, because of a FCS (frame + check sequence) error). + +* ppp_channel_index() returns the channel index assigned by the PPP + generic layer to this channel. The channel should provide some way + (e.g. an ioctl) to transmit this back to user-space, as user-space + will need it to attach an instance of /dev/ppp to this channel. + +* ppp_unit_number() returns the unit number of the ppp network + interface to which this channel is connected, or -1 if the channel + is not connected. + +Connecting a channel to the ppp generic layer is initiated from the +channel code, rather than from the generic layer. The channel is +expected to have some way for a user-level process to control it +independently of the ppp generic layer. For example, with the +ppp_async channel, this is provided by the file descriptor to the +serial port. + +Generally a user-level process will initialize the underlying +communications medium and prepare it to do PPP. For example, with an +async tty, this can involve setting the tty speed and modes, issuing +modem commands, and then going through some sort of dialog with the +remote system to invoke PPP service there. We refer to this process +as ``discovery``. Then the user-level process tells the medium to +become a PPP channel and register itself with the generic PPP layer. +The channel then has to report the channel number assigned to it back +to the user-level process. From that point, the PPP negotiation code +in the PPP daemon (pppd) can take over and perform the PPP +negotiation, accessing the channel through the /dev/ppp interface. + +At the interface to the PPP generic layer, PPP frames are stored in +skbuff structures and start with the two-byte PPP protocol number. +The frame does *not* include the 0xff ``address`` byte or the 0x03 +``control`` byte that are optionally used in async PPP. Nor is there +any escaping of control characters, nor are there any FCS or framing +characters included. That is all the responsibility of the channel +code, if it is needed for the particular medium. That is, the skbuffs +presented to the start_xmit() function contain only the 2-byte +protocol number and the data, and the skbuffs presented to ppp_input() +must be in the same format. + +The channel must provide an instance of a ppp_channel struct to +represent the channel. The channel is free to use the ``private`` field +however it wishes. The channel should initialize the ``mtu`` and +``hdrlen`` fields before calling ppp_register_channel() and not change +them until after ppp_unregister_channel() returns. The ``mtu`` field +represents the maximum size of the data part of the PPP frames, that +is, it does not include the 2-byte protocol number. + +If the channel needs some headroom in the skbuffs presented to it for +transmission (i.e., some space free in the skbuff data area before the +start of the PPP frame), it should set the ``hdrlen`` field of the +ppp_channel struct to the amount of headroom required. The generic +PPP layer will attempt to provide that much headroom but the channel +should still check if there is sufficient headroom and copy the skbuff +if there isn't. + +On the input side, channels should ideally provide at least 2 bytes of +headroom in the skbuffs presented to ppp_input(). The generic PPP +code does not require this but will be more efficient if this is done. + + +Buffering and flow control +-------------------------- + +The generic PPP layer has been designed to minimize the amount of data +that it buffers in the transmit direction. It maintains a queue of +transmit packets for the PPP unit (network interface device) plus a +queue of transmit packets for each attached channel. Normally the +transmit queue for the unit will contain at most one packet; the +exceptions are when pppd sends packets by writing to /dev/ppp, and +when the core networking code calls the generic layer's start_xmit() +function with the queue stopped, i.e. when the generic layer has +called netif_stop_queue(), which only happens on a transmit timeout. +The start_xmit function always accepts and queues the packet which it +is asked to transmit. + +Transmit packets are dequeued from the PPP unit transmit queue and +then subjected to TCP/IP header compression and packet compression +(Deflate or BSD-Compress compression), as appropriate. After this +point the packets can no longer be reordered, as the decompression +algorithms rely on receiving compressed packets in the same order that +they were generated. + +If multilink is not in use, this packet is then passed to the attached +channel's start_xmit() function. If the channel refuses to take +the packet, the generic layer saves it for later transmission. The +generic layer will call the channel's start_xmit() function again +when the channel calls ppp_output_wakeup() or when the core +networking code calls the generic layer's start_xmit() function +again. The generic layer contains no timeout and retransmission +logic; it relies on the core networking code for that. + +If multilink is in use, the generic layer divides the packet into one +or more fragments and puts a multilink header on each fragment. It +decides how many fragments to use based on the length of the packet +and the number of channels which are potentially able to accept a +fragment at the moment. A channel is potentially able to accept a +fragment if it doesn't have any fragments currently queued up for it +to transmit. The channel may still refuse a fragment; in this case +the fragment is queued up for the channel to transmit later. This +scheme has the effect that more fragments are given to higher- +bandwidth channels. It also means that under light load, the generic +layer will tend to fragment large packets across all the channels, +thus reducing latency, while under heavy load, packets will tend to be +transmitted as single fragments, thus reducing the overhead of +fragmentation. + + +SMP safety +---------- + +The PPP generic layer has been designed to be SMP-safe. Locks are +used around accesses to the internal data structures where necessary +to ensure their integrity. As part of this, the generic layer +requires that the channels adhere to certain requirements and in turn +provides certain guarantees to the channels. Essentially the channels +are required to provide the appropriate locking on the ppp_channel +structures that form the basis of the communication between the +channel and the generic layer. This is because the channel provides +the storage for the ppp_channel structure, and so the channel is +required to provide the guarantee that this storage exists and is +valid at the appropriate times. + +The generic layer requires these guarantees from the channel: + +* The ppp_channel object must exist from the time that + ppp_register_channel() is called until after the call to + ppp_unregister_channel() returns. + +* No thread may be in a call to any of ppp_input(), ppp_input_error(), + ppp_output_wakeup(), ppp_channel_index() or ppp_unit_number() for a + channel at the time that ppp_unregister_channel() is called for that + channel. + +* ppp_register_channel() and ppp_unregister_channel() must be called + from process context, not interrupt or softirq/BH context. + +* The remaining generic layer functions may be called at softirq/BH + level but must not be called from a hardware interrupt handler. + +* The generic layer may call the channel start_xmit() function at + softirq/BH level but will not call it at interrupt level. Thus the + start_xmit() function may not block. + +* The generic layer will only call the channel ioctl() function in + process context. + +The generic layer provides these guarantees to the channels: + +* The generic layer will not call the start_xmit() function for a + channel while any thread is already executing in that function for + that channel. + +* The generic layer will not call the ioctl() function for a channel + while any thread is already executing in that function for that + channel. + +* By the time a call to ppp_unregister_channel() returns, no thread + will be executing in a call from the generic layer to that channel's + start_xmit() or ioctl() function, and the generic layer will not + call either of those functions subsequently. + + +Interface to pppd +----------------- + +The PPP generic layer exports a character device interface called +/dev/ppp. This is used by pppd to control PPP interface units and +channels. Although there is only one /dev/ppp, each open instance of +/dev/ppp acts independently and can be attached either to a PPP unit +or a PPP channel. This is achieved using the file->private_data field +to point to a separate object for each open instance of /dev/ppp. In +this way an effect similar to Solaris' clone open is obtained, +allowing us to control an arbitrary number of PPP interfaces and +channels without having to fill up /dev with hundreds of device names. + +When /dev/ppp is opened, a new instance is created which is initially +unattached. Using an ioctl call, it can then be attached to an +existing unit, attached to a newly-created unit, or attached to an +existing channel. An instance attached to a unit can be used to send +and receive PPP control frames, using the read() and write() system +calls, along with poll() if necessary. Similarly, an instance +attached to a channel can be used to send and receive PPP frames on +that channel. + +In multilink terms, the unit represents the bundle, while the channels +represent the individual physical links. Thus, a PPP frame sent by a +write to the unit (i.e., to an instance of /dev/ppp attached to the +unit) will be subject to bundle-level compression and to fragmentation +across the individual links (if multilink is in use). In contrast, a +PPP frame sent by a write to the channel will be sent as-is on that +channel, without any multilink header. + +A channel is not initially attached to any unit. In this state it can +be used for PPP negotiation but not for the transfer of data packets. +It can then be connected to a PPP unit with an ioctl call, which +makes it available to send and receive data packets for that unit. + +The ioctl calls which are available on an instance of /dev/ppp depend +on whether it is unattached, attached to a PPP interface, or attached +to a PPP channel. The ioctl calls which are available on an +unattached instance are: + +* PPPIOCNEWUNIT creates a new PPP interface and makes this /dev/ppp + instance the "owner" of the interface. The argument should point to + an int which is the desired unit number if >= 0, or -1 to assign the + lowest unused unit number. Being the owner of the interface means + that the interface will be shut down if this instance of /dev/ppp is + closed. + +* PPPIOCATTACH attaches this instance to an existing PPP interface. + The argument should point to an int containing the unit number. + This does not make this instance the owner of the PPP interface. + +* PPPIOCATTCHAN attaches this instance to an existing PPP channel. + The argument should point to an int containing the channel number. + +The ioctl calls available on an instance of /dev/ppp attached to a +channel are: + +* PPPIOCCONNECT connects this channel to a PPP interface. The + argument should point to an int containing the interface unit + number. It will return an EINVAL error if the channel is already + connected to an interface, or ENXIO if the requested interface does + not exist. + +* PPPIOCDISCONN disconnects this channel from the PPP interface that + it is connected to. It will return an EINVAL error if the channel + is not connected to an interface. + +* PPPIOCBRIDGECHAN bridges a channel with another. The argument should + point to an int containing the channel number of the channel to bridge + to. Once two channels are bridged, frames presented to one channel by + ppp_input() are passed to the bridge instance for onward transmission. + This allows frames to be switched from one channel into another: for + example, to pass PPPoE frames into a PPPoL2TP session. Since channel + bridging interrupts the normal ppp_input() path, a given channel may + not be part of a bridge at the same time as being part of a unit. + This ioctl will return an EALREADY error if the channel is already + part of a bridge or unit, or ENXIO if the requested channel does not + exist. + +* PPPIOCUNBRIDGECHAN performs the inverse of PPPIOCBRIDGECHAN, unbridging + a channel pair. This ioctl will return an EINVAL error if the channel + does not form part of a bridge. + +* All other ioctl commands are passed to the channel ioctl() function. + +The ioctl calls that are available on an instance that is attached to +an interface unit are: + +* PPPIOCSMRU sets the MRU (maximum receive unit) for the interface. + The argument should point to an int containing the new MRU value. + +* PPPIOCSFLAGS sets flags which control the operation of the + interface. The argument should be a pointer to an int containing + the new flags value. The bits in the flags value that can be set + are: + + ================ ======================================== + SC_COMP_TCP enable transmit TCP header compression + SC_NO_TCP_CCID disable connection-id compression for + TCP header compression + SC_REJ_COMP_TCP disable receive TCP header decompression + SC_CCP_OPEN Compression Control Protocol (CCP) is + open, so inspect CCP packets + SC_CCP_UP CCP is up, may (de)compress packets + SC_LOOP_TRAFFIC send IP traffic to pppd + SC_MULTILINK enable PPP multilink fragmentation on + transmitted packets + SC_MP_SHORTSEQ expect short multilink sequence + numbers on received multilink fragments + SC_MP_XSHORTSEQ transmit short multilink sequence nos. + ================ ======================================== + + The values of these flags are defined in <linux/ppp-ioctl.h>. Note + that the values of the SC_MULTILINK, SC_MP_SHORTSEQ and + SC_MP_XSHORTSEQ bits are ignored if the CONFIG_PPP_MULTILINK option + is not selected. + +* PPPIOCGFLAGS returns the value of the status/control flags for the + interface unit. The argument should point to an int where the ioctl + will store the flags value. As well as the values listed above for + PPPIOCSFLAGS, the following bits may be set in the returned value: + + ================ ========================================= + SC_COMP_RUN CCP compressor is running + SC_DECOMP_RUN CCP decompressor is running + SC_DC_ERROR CCP decompressor detected non-fatal error + SC_DC_FERROR CCP decompressor detected fatal error + ================ ========================================= + +* PPPIOCSCOMPRESS sets the parameters for packet compression or + decompression. The argument should point to a ppp_option_data + structure (defined in <linux/ppp-ioctl.h>), which contains a + pointer/length pair which should describe a block of memory + containing a CCP option specifying a compression method and its + parameters. The ppp_option_data struct also contains a ``transmit`` + field. If this is 0, the ioctl will affect the receive path, + otherwise the transmit path. + +* PPPIOCGUNIT returns, in the int pointed to by the argument, the unit + number of this interface unit. + +* PPPIOCSDEBUG sets the debug flags for the interface to the value in + the int pointed to by the argument. Only the least significant bit + is used; if this is 1 the generic layer will print some debug + messages during its operation. This is only intended for debugging + the generic PPP layer code; it is generally not helpful for working + out why a PPP connection is failing. + +* PPPIOCGDEBUG returns the debug flags for the interface in the int + pointed to by the argument. + +* PPPIOCGIDLE returns the time, in seconds, since the last data + packets were sent and received. The argument should point to a + ppp_idle structure (defined in <linux/ppp_defs.h>). If the + CONFIG_PPP_FILTER option is enabled, the set of packets which reset + the transmit and receive idle timers is restricted to those which + pass the ``active`` packet filter. + Two versions of this command exist, to deal with user space + expecting times as either 32-bit or 64-bit time_t seconds. + +* PPPIOCSMAXCID sets the maximum connection-ID parameter (and thus the + number of connection slots) for the TCP header compressor and + decompressor. The lower 16 bits of the int pointed to by the + argument specify the maximum connection-ID for the compressor. If + the upper 16 bits of that int are non-zero, they specify the maximum + connection-ID for the decompressor, otherwise the decompressor's + maximum connection-ID is set to 15. + +* PPPIOCSNPMODE sets the network-protocol mode for a given network + protocol. The argument should point to an npioctl struct (defined + in <linux/ppp-ioctl.h>). The ``protocol`` field gives the PPP protocol + number for the protocol to be affected, and the ``mode`` field + specifies what to do with packets for that protocol: + + ============= ============================================== + NPMODE_PASS normal operation, transmit and receive packets + NPMODE_DROP silently drop packets for this protocol + NPMODE_ERROR drop packets and return an error on transmit + NPMODE_QUEUE queue up packets for transmit, drop received + packets + ============= ============================================== + + At present NPMODE_ERROR and NPMODE_QUEUE have the same effect as + NPMODE_DROP. + +* PPPIOCGNPMODE returns the network-protocol mode for a given + protocol. The argument should point to an npioctl struct with the + ``protocol`` field set to the PPP protocol number for the protocol of + interest. On return the ``mode`` field will be set to the network- + protocol mode for that protocol. + +* PPPIOCSPASS and PPPIOCSACTIVE set the ``pass`` and ``active`` packet + filters. These ioctls are only available if the CONFIG_PPP_FILTER + option is selected. The argument should point to a sock_fprog + structure (defined in <linux/filter.h>) containing the compiled BPF + instructions for the filter. Packets are dropped if they fail the + ``pass`` filter; otherwise, if they fail the ``active`` filter they are + passed but they do not reset the transmit or receive idle timer. + +* PPPIOCSMRRU enables or disables multilink processing for received + packets and sets the multilink MRRU (maximum reconstructed receive + unit). The argument should point to an int containing the new MRRU + value. If the MRRU value is 0, processing of received multilink + fragments is disabled. This ioctl is only available if the + CONFIG_PPP_MULTILINK option is selected. + +Last modified: 7-feb-2002 diff --git a/Documentation/networking/proc_net_tcp.rst b/Documentation/networking/proc_net_tcp.rst new file mode 100644 index 0000000000..7d9dfe36af --- /dev/null +++ b/Documentation/networking/proc_net_tcp.rst @@ -0,0 +1,57 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================================ +The proc/net/tcp and proc/net/tcp6 variables +============================================ + +This document describes the interfaces /proc/net/tcp and /proc/net/tcp6. +Note that these interfaces are deprecated in favor of tcp_diag. + +These /proc interfaces provide information about currently active TCP +connections, and are implemented by tcp4_seq_show() in net/ipv4/tcp_ipv4.c +and tcp6_seq_show() in net/ipv6/tcp_ipv6.c, respectively. + +It will first list all listening TCP sockets, and next list all established +TCP connections. A typical entry of /proc/net/tcp would look like this (split +up into 3 parts because of the length of the line):: + + 46: 010310AC:9C4C 030310AC:1770 01 + | | | | | |--> connection state + | | | | |------> remote TCP port number + | | | |-------------> remote IPv4 address + | | |--------------------> local TCP port number + | |---------------------------> local IPv4 address + |----------------------------------> number of entry + + 00000150:00000000 01:00000019 00000000 + | | | | |--> number of unrecovered RTO timeouts + | | | |----------> number of jiffies until timer expires + | | |----------------> timer_active (see below) + | |----------------------> receive-queue + |-------------------------------> transmit-queue + + 1000 0 54165785 4 cd1e6040 25 4 27 3 -1 + | | | | | | | | | |--> slow start size threshold, + | | | | | | | | | or -1 if the threshold + | | | | | | | | | is >= 0xFFFF + | | | | | | | | |----> sending congestion window + | | | | | | | |-------> (ack.quick<<1)|ack.pingpong + | | | | | | |---------> Predicted tick of soft clock + | | | | | | (delayed ACK control data) + | | | | | |------------> retransmit timeout + | | | | |------------------> location of socket in memory + | | | |-----------------------> socket reference count + | | |-----------------------------> inode + | |----------------------------------> unanswered 0-window probes + |---------------------------------------------> uid + +timer_active: + + == ================================================================ + 0 no timer is pending + 1 retransmit-timer is pending + 2 another timer (e.g. delayed ack or keepalive) is pending + 3 this is a socket in TIME_WAIT state. Not all fields will contain + data (or even exist) + 4 zero window probe timer is pending + == ================================================================ diff --git a/Documentation/networking/radiotap-headers.rst b/Documentation/networking/radiotap-headers.rst new file mode 100644 index 0000000000..1a1bd1ec06 --- /dev/null +++ b/Documentation/networking/radiotap-headers.rst @@ -0,0 +1,159 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=========================== +How to use radiotap headers +=========================== + +Pointer to the radiotap include file +------------------------------------ + +Radiotap headers are variable-length and extensible, you can get most of the +information you need to know on them from:: + + ./include/net/ieee80211_radiotap.h + +This document gives an overview and warns on some corner cases. + + +Structure of the header +----------------------- + +There is a fixed portion at the start which contains a u32 bitmap that defines +if the possible argument associated with that bit is present or not. So if b0 +of the it_present member of ieee80211_radiotap_header is set, it means that +the header for argument index 0 (IEEE80211_RADIOTAP_TSFT) is present in the +argument area. + +:: + + < 8-byte ieee80211_radiotap_header > + [ <possible argument bitmap extensions ... > ] + [ <argument> ... ] + +At the moment there are only 13 possible argument indexes defined, but in case +we run out of space in the u32 it_present member, it is defined that b31 set +indicates that there is another u32 bitmap following (shown as "possible +argument bitmap extensions..." above), and the start of the arguments is moved +forward 4 bytes each time. + +Note also that the it_len member __le16 is set to the total number of bytes +covered by the ieee80211_radiotap_header and any arguments following. + + +Requirements for arguments +-------------------------- + +After the fixed part of the header, the arguments follow for each argument +index whose matching bit is set in the it_present member of +ieee80211_radiotap_header. + + - the arguments are all stored little-endian! + + - the argument payload for a given argument index has a fixed size. So + IEEE80211_RADIOTAP_TSFT being present always indicates an 8-byte argument is + present. See the comments in ./include/net/ieee80211_radiotap.h for a nice + breakdown of all the argument sizes + + - the arguments must be aligned to a boundary of the argument size using + padding. So a u16 argument must start on the next u16 boundary if it isn't + already on one, a u32 must start on the next u32 boundary and so on. + + - "alignment" is relative to the start of the ieee80211_radiotap_header, ie, + the first byte of the radiotap header. The absolute alignment of that first + byte isn't defined. So even if the whole radiotap header is starting at, eg, + address 0x00000003, still the first byte of the radiotap header is treated as + 0 for alignment purposes. + + - the above point that there may be no absolute alignment for multibyte + entities in the fixed radiotap header or the argument region means that you + have to take special evasive action when trying to access these multibyte + entities. Some arches like Blackfin cannot deal with an attempt to + dereference, eg, a u16 pointer that is pointing to an odd address. Instead + you have to use a kernel API get_unaligned() to dereference the pointer, + which will do it bytewise on the arches that require that. + + - The arguments for a given argument index can be a compound of multiple types + together. For example IEEE80211_RADIOTAP_CHANNEL has an argument payload + consisting of two u16s of total length 4. When this happens, the padding + rule is applied dealing with a u16, NOT dealing with a 4-byte single entity. + + +Example valid radiotap header +----------------------------- + +:: + + 0x00, 0x00, // <-- radiotap version + pad byte + 0x0b, 0x00, // <- radiotap header length + 0x04, 0x0c, 0x00, 0x00, // <-- bitmap + 0x6c, // <-- rate (in 500kHz units) + 0x0c, //<-- tx power + 0x01 //<-- antenna + + +Using the Radiotap Parser +------------------------- + +If you are having to parse a radiotap struct, you can radically simplify the +job by using the radiotap parser that lives in net/wireless/radiotap.c and has +its prototypes available in include/net/cfg80211.h. You use it like this:: + + #include <net/cfg80211.h> + + /* buf points to the start of the radiotap header part */ + + int MyFunction(u8 * buf, int buflen) + { + int pkt_rate_100kHz = 0, antenna = 0, pwr = 0; + struct ieee80211_radiotap_iterator iterator; + int ret = ieee80211_radiotap_iterator_init(&iterator, buf, buflen); + + while (!ret) { + + ret = ieee80211_radiotap_iterator_next(&iterator); + + if (ret) + continue; + + /* see if this argument is something we can use */ + + switch (iterator.this_arg_index) { + /* + * You must take care when dereferencing iterator.this_arg + * for multibyte types... the pointer is not aligned. Use + * get_unaligned((type *)iterator.this_arg) to dereference + * iterator.this_arg for type "type" safely on all arches. + */ + case IEEE80211_RADIOTAP_RATE: + /* radiotap "rate" u8 is in + * 500kbps units, eg, 0x02=1Mbps + */ + pkt_rate_100kHz = (*iterator.this_arg) * 5; + break; + + case IEEE80211_RADIOTAP_ANTENNA: + /* radiotap uses 0 for 1st ant */ + antenna = *iterator.this_arg); + break; + + case IEEE80211_RADIOTAP_DBM_TX_POWER: + pwr = *iterator.this_arg; + break; + + default: + break; + } + } /* while more rt headers */ + + if (ret != -ENOENT) + return TXRX_DROP; + + /* discard the radiotap header part */ + buf += iterator.max_length; + buflen -= iterator.max_length; + + ... + + } + +Andy Green <andy@warmcat.com> diff --git a/Documentation/networking/rds.rst b/Documentation/networking/rds.rst new file mode 100644 index 0000000000..498395f5fb --- /dev/null +++ b/Documentation/networking/rds.rst @@ -0,0 +1,448 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=== +RDS +=== + +Overview +======== + +This readme tries to provide some background on the hows and whys of RDS, +and will hopefully help you find your way around the code. + +In addition, please see this email about RDS origins: +http://oss.oracle.com/pipermail/rds-devel/2007-November/000228.html + +RDS Architecture +================ + +RDS provides reliable, ordered datagram delivery by using a single +reliable connection between any two nodes in the cluster. This allows +applications to use a single socket to talk to any other process in the +cluster - so in a cluster with N processes you need N sockets, in contrast +to N*N if you use a connection-oriented socket transport like TCP. + +RDS is not Infiniband-specific; it was designed to support different +transports. The current implementation used to support RDS over TCP as well +as IB. + +The high-level semantics of RDS from the application's point of view are + + * Addressing + + RDS uses IPv4 addresses and 16bit port numbers to identify + the end point of a connection. All socket operations that involve + passing addresses between kernel and user space generally + use a struct sockaddr_in. + + The fact that IPv4 addresses are used does not mean the underlying + transport has to be IP-based. In fact, RDS over IB uses a + reliable IB connection; the IP address is used exclusively to + locate the remote node's GID (by ARPing for the given IP). + + The port space is entirely independent of UDP, TCP or any other + protocol. + + * Socket interface + + RDS sockets work *mostly* as you would expect from a BSD + socket. The next section will cover the details. At any rate, + all I/O is performed through the standard BSD socket API. + Some additions like zerocopy support are implemented through + control messages, while other extensions use the getsockopt/ + setsockopt calls. + + Sockets must be bound before you can send or receive data. + This is needed because binding also selects a transport and + attaches it to the socket. Once bound, the transport assignment + does not change. RDS will tolerate IPs moving around (eg in + a active-active HA scenario), but only as long as the address + doesn't move to a different transport. + + * sysctls + + RDS supports a number of sysctls in /proc/sys/net/rds + + +Socket Interface +================ + + AF_RDS, PF_RDS, SOL_RDS + AF_RDS and PF_RDS are the domain type to be used with socket(2) + to create RDS sockets. SOL_RDS is the socket-level to be used + with setsockopt(2) and getsockopt(2) for RDS specific socket + options. + + fd = socket(PF_RDS, SOCK_SEQPACKET, 0); + This creates a new, unbound RDS socket. + + setsockopt(SOL_SOCKET): send and receive buffer size + RDS honors the send and receive buffer size socket options. + You are not allowed to queue more than SO_SNDSIZE bytes to + a socket. A message is queued when sendmsg is called, and + it leaves the queue when the remote system acknowledges + its arrival. + + The SO_RCVSIZE option controls the maximum receive queue length. + This is a soft limit rather than a hard limit - RDS will + continue to accept and queue incoming messages, even if that + takes the queue length over the limit. However, it will also + mark the port as "congested" and send a congestion update to + the source node. The source node is supposed to throttle any + processes sending to this congested port. + + bind(fd, &sockaddr_in, ...) + This binds the socket to a local IP address and port, and a + transport, if one has not already been selected via the + SO_RDS_TRANSPORT socket option + + sendmsg(fd, ...) + Sends a message to the indicated recipient. The kernel will + transparently establish the underlying reliable connection + if it isn't up yet. + + An attempt to send a message that exceeds SO_SNDSIZE will + return with -EMSGSIZE + + An attempt to send a message that would take the total number + of queued bytes over the SO_SNDSIZE threshold will return + EAGAIN. + + An attempt to send a message to a destination that is marked + as "congested" will return ENOBUFS. + + recvmsg(fd, ...) + Receives a message that was queued to this socket. The sockets + recv queue accounting is adjusted, and if the queue length + drops below SO_SNDSIZE, the port is marked uncongested, and + a congestion update is sent to all peers. + + Applications can ask the RDS kernel module to receive + notifications via control messages (for instance, there is a + notification when a congestion update arrived, or when a RDMA + operation completes). These notifications are received through + the msg.msg_control buffer of struct msghdr. The format of the + messages is described in manpages. + + poll(fd) + RDS supports the poll interface to allow the application + to implement async I/O. + + POLLIN handling is pretty straightforward. When there's an + incoming message queued to the socket, or a pending notification, + we signal POLLIN. + + POLLOUT is a little harder. Since you can essentially send + to any destination, RDS will always signal POLLOUT as long as + there's room on the send queue (ie the number of bytes queued + is less than the sendbuf size). + + However, the kernel will refuse to accept messages to + a destination marked congested - in this case you will loop + forever if you rely on poll to tell you what to do. + This isn't a trivial problem, but applications can deal with + this - by using congestion notifications, and by checking for + ENOBUFS errors returned by sendmsg. + + setsockopt(SOL_RDS, RDS_CANCEL_SENT_TO, &sockaddr_in) + This allows the application to discard all messages queued to a + specific destination on this particular socket. + + This allows the application to cancel outstanding messages if + it detects a timeout. For instance, if it tried to send a message, + and the remote host is unreachable, RDS will keep trying forever. + The application may decide it's not worth it, and cancel the + operation. In this case, it would use RDS_CANCEL_SENT_TO to + nuke any pending messages. + + ``setsockopt(fd, SOL_RDS, SO_RDS_TRANSPORT, (int *)&transport ..), getsockopt(fd, SOL_RDS, SO_RDS_TRANSPORT, (int *)&transport ..)`` + Set or read an integer defining the underlying + encapsulating transport to be used for RDS packets on the + socket. When setting the option, integer argument may be + one of RDS_TRANS_TCP or RDS_TRANS_IB. When retrieving the + value, RDS_TRANS_NONE will be returned on an unbound socket. + This socket option may only be set exactly once on the socket, + prior to binding it via the bind(2) system call. Attempts to + set SO_RDS_TRANSPORT on a socket for which the transport has + been previously attached explicitly (by SO_RDS_TRANSPORT) or + implicitly (via bind(2)) will return an error of EOPNOTSUPP. + An attempt to set SO_RDS_TRANSPORT to RDS_TRANS_NONE will + always return EINVAL. + +RDMA for RDS +============ + + see rds-rdma(7) manpage (available in rds-tools) + + +Congestion Notifications +======================== + + see rds(7) manpage + + +RDS Protocol +============ + + Message header + + The message header is a 'struct rds_header' (see rds.h): + + Fields: + + h_sequence: + per-packet sequence number + h_ack: + piggybacked acknowledgment of last packet received + h_len: + length of data, not including header + h_sport: + source port + h_dport: + destination port + h_flags: + Can be: + + ============= ================================== + CONG_BITMAP this is a congestion update bitmap + ACK_REQUIRED receiver must ack this packet + RETRANSMITTED packet has previously been sent + ============= ================================== + + h_credit: + indicate to other end of connection that + it has more credits available (i.e. there is + more send room) + h_padding[4]: + unused, for future use + h_csum: + header checksum + h_exthdr: + optional data can be passed here. This is currently used for + passing RDMA-related information. + + ACK and retransmit handling + + One might think that with reliable IB connections you wouldn't need + to ack messages that have been received. The problem is that IB + hardware generates an ack message before it has DMAed the message + into memory. This creates a potential message loss if the HCA is + disabled for any reason between when it sends the ack and before + the message is DMAed and processed. This is only a potential issue + if another HCA is available for fail-over. + + Sending an ack immediately would allow the sender to free the sent + message from their send queue quickly, but could cause excessive + traffic to be used for acks. RDS piggybacks acks on sent data + packets. Ack-only packets are reduced by only allowing one to be + in flight at a time, and by the sender only asking for acks when + its send buffers start to fill up. All retransmissions are also + acked. + + Flow Control + + RDS's IB transport uses a credit-based mechanism to verify that + there is space in the peer's receive buffers for more data. This + eliminates the need for hardware retries on the connection. + + Congestion + + Messages waiting in the receive queue on the receiving socket + are accounted against the sockets SO_RCVBUF option value. Only + the payload bytes in the message are accounted for. If the + number of bytes queued equals or exceeds rcvbuf then the socket + is congested. All sends attempted to this socket's address + should return block or return -EWOULDBLOCK. + + Applications are expected to be reasonably tuned such that this + situation very rarely occurs. An application encountering this + "back-pressure" is considered a bug. + + This is implemented by having each node maintain bitmaps which + indicate which ports on bound addresses are congested. As the + bitmap changes it is sent through all the connections which + terminate in the local address of the bitmap which changed. + + The bitmaps are allocated as connections are brought up. This + avoids allocation in the interrupt handling path which queues + sages on sockets. The dense bitmaps let transports send the + entire bitmap on any bitmap change reasonably efficiently. This + is much easier to implement than some finer-grained + communication of per-port congestion. The sender does a very + inexpensive bit test to test if the port it's about to send to + is congested or not. + + +RDS Transport Layer +=================== + + As mentioned above, RDS is not IB-specific. Its code is divided + into a general RDS layer and a transport layer. + + The general layer handles the socket API, congestion handling, + loopback, stats, usermem pinning, and the connection state machine. + + The transport layer handles the details of the transport. The IB + transport, for example, handles all the queue pairs, work requests, + CM event handlers, and other Infiniband details. + + +RDS Kernel Structures +===================== + + struct rds_message + aka possibly "rds_outgoing", the generic RDS layer copies data to + be sent and sets header fields as needed, based on the socket API. + This is then queued for the individual connection and sent by the + connection's transport. + + struct rds_incoming + a generic struct referring to incoming data that can be handed from + the transport to the general code and queued by the general code + while the socket is awoken. It is then passed back to the transport + code to handle the actual copy-to-user. + + struct rds_socket + per-socket information + + struct rds_connection + per-connection information + + struct rds_transport + pointers to transport-specific functions + + struct rds_statistics + non-transport-specific statistics + + struct rds_cong_map + wraps the raw congestion bitmap, contains rbnode, waitq, etc. + +Connection management +===================== + + Connections may be in UP, DOWN, CONNECTING, DISCONNECTING, and + ERROR states. + + The first time an attempt is made by an RDS socket to send data to + a node, a connection is allocated and connected. That connection is + then maintained forever -- if there are transport errors, the + connection will be dropped and re-established. + + Dropping a connection while packets are queued will cause queued or + partially-sent datagrams to be retransmitted when the connection is + re-established. + + +The send path +============= + + rds_sendmsg() + - struct rds_message built from incoming data + - CMSGs parsed (e.g. RDMA ops) + - transport connection alloced and connected if not already + - rds_message placed on send queue + - send worker awoken + + rds_send_worker() + - calls rds_send_xmit() until queue is empty + + rds_send_xmit() + - transmits congestion map if one is pending + - may set ACK_REQUIRED + - calls transport to send either non-RDMA or RDMA message + (RDMA ops never retransmitted) + + rds_ib_xmit() + - allocs work requests from send ring + - adds any new send credits available to peer (h_credits) + - maps the rds_message's sg list + - piggybacks ack + - populates work requests + - post send to connection's queue pair + +The recv path +============= + + rds_ib_recv_cq_comp_handler() + - looks at write completions + - unmaps recv buffer from device + - no errors, call rds_ib_process_recv() + - refill recv ring + + rds_ib_process_recv() + - validate header checksum + - copy header to rds_ib_incoming struct if start of a new datagram + - add to ibinc's fraglist + - if competed datagram: + - update cong map if datagram was cong update + - call rds_recv_incoming() otherwise + - note if ack is required + + rds_recv_incoming() + - drop duplicate packets + - respond to pings + - find the sock associated with this datagram + - add to sock queue + - wake up sock + - do some congestion calculations + rds_recvmsg + - copy data into user iovec + - handle CMSGs + - return to application + +Multipath RDS (mprds) +===================== + Mprds is multipathed-RDS, primarily intended for RDS-over-TCP + (though the concept can be extended to other transports). The classical + implementation of RDS-over-TCP is implemented by demultiplexing multiple + PF_RDS sockets between any 2 endpoints (where endpoint == [IP address, + port]) over a single TCP socket between the 2 IP addresses involved. This + has the limitation that it ends up funneling multiple RDS flows over a + single TCP flow, thus it is + (a) upper-bounded to the single-flow bandwidth, + (b) suffers from head-of-line blocking for all the RDS sockets. + + Better throughput (for a fixed small packet size, MTU) can be achieved + by having multiple TCP/IP flows per rds/tcp connection, i.e., multipathed + RDS (mprds). Each such TCP/IP flow constitutes a path for the rds/tcp + connection. RDS sockets will be attached to a path based on some hash + (e.g., of local address and RDS port number) and packets for that RDS + socket will be sent over the attached path using TCP to segment/reassemble + RDS datagrams on that path. + + Multipathed RDS is implemented by splitting the struct rds_connection into + a common (to all paths) part, and a per-path struct rds_conn_path. All + I/O workqs and reconnect threads are driven from the rds_conn_path. + Transports such as TCP that are multipath capable may then set up a + TCP socket per rds_conn_path, and this is managed by the transport via + the transport privatee cp_transport_data pointer. + + Transports announce themselves as multipath capable by setting the + t_mp_capable bit during registration with the rds core module. When the + transport is multipath-capable, rds_sendmsg() hashes outgoing traffic + across multiple paths. The outgoing hash is computed based on the + local address and port that the PF_RDS socket is bound to. + + Additionally, even if the transport is MP capable, we may be + peering with some node that does not support mprds, or supports + a different number of paths. As a result, the peering nodes need + to agree on the number of paths to be used for the connection. + This is done by sending out a control packet exchange before the + first data packet. The control packet exchange must have completed + prior to outgoing hash completion in rds_sendmsg() when the transport + is mutlipath capable. + + The control packet is an RDS ping packet (i.e., packet to rds dest + port 0) with the ping packet having a rds extension header option of + type RDS_EXTHDR_NPATHS, length 2 bytes, and the value is the + number of paths supported by the sender. The "probe" ping packet will + get sent from some reserved port, RDS_FLAG_PROBE_PORT (in <linux/rds.h>) + The receiver of a ping from RDS_FLAG_PROBE_PORT will thus immediately + be able to compute the min(sender_paths, rcvr_paths). The pong + sent in response to a probe-ping should contain the rcvr's npaths + when the rcvr is mprds-capable. + + If the rcvr is not mprds-capable, the exthdr in the ping will be + ignored. In this case the pong will not have any exthdrs, so the sender + of the probe-ping can default to single-path mprds. + diff --git a/Documentation/networking/regulatory.rst b/Documentation/networking/regulatory.rst new file mode 100644 index 0000000000..5e42c8a175 --- /dev/null +++ b/Documentation/networking/regulatory.rst @@ -0,0 +1,209 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======================================= +Linux wireless regulatory documentation +======================================= + +This document gives a brief review over how the Linux wireless +regulatory infrastructure works. + +More up to date information can be obtained at the project's web page: + +https://wireless.wiki.kernel.org/en/developers/Regulatory + +Keeping regulatory domains in userspace +--------------------------------------- + +Due to the dynamic nature of regulatory domains we keep them +in userspace and provide a framework for userspace to upload +to the kernel one regulatory domain to be used as the central +core regulatory domain all wireless devices should adhere to. + +How to get regulatory domains to the kernel +------------------------------------------- + +When the regulatory domain is first set up, the kernel will request a +database file (regulatory.db) containing all the regulatory rules. It +will then use that database when it needs to look up the rules for a +given country. + +How to get regulatory domains to the kernel (old CRDA solution) +--------------------------------------------------------------- + +Userspace gets a regulatory domain in the kernel by having +a userspace agent build it and send it via nl80211. Only +expected regulatory domains will be respected by the kernel. + +A currently available userspace agent which can accomplish this +is CRDA - central regulatory domain agent. Its documented here: + +https://wireless.wiki.kernel.org/en/developers/Regulatory/CRDA + +Essentially the kernel will send a udev event when it knows +it needs a new regulatory domain. A udev rule can be put in place +to trigger crda to send the respective regulatory domain for a +specific ISO/IEC 3166 alpha2. + +Below is an example udev rule which can be used: + +# Example file, should be put in /etc/udev/rules.d/regulatory.rules +KERNEL=="regulatory*", ACTION=="change", SUBSYSTEM=="platform", RUN+="/sbin/crda" + +The alpha2 is passed as an environment variable under the variable COUNTRY. + +Who asks for regulatory domains? +-------------------------------- + +* Users + +Users can use iw: + +https://wireless.wiki.kernel.org/en/users/Documentation/iw + +An example:: + + # set regulatory domain to "Costa Rica" + iw reg set CR + +This will request the kernel to set the regulatory domain to +the specified alpha2. The kernel in turn will then ask userspace +to provide a regulatory domain for the alpha2 specified by the user +by sending a uevent. + +* Wireless subsystems for Country Information elements + +The kernel will send a uevent to inform userspace a new +regulatory domain is required. More on this to be added +as its integration is added. + +* Drivers + +If drivers determine they need a specific regulatory domain +set they can inform the wireless core using regulatory_hint(). +They have two options -- they either provide an alpha2 so that +crda can provide back a regulatory domain for that country or +they can build their own regulatory domain based on internal +custom knowledge so the wireless core can respect it. + +*Most* drivers will rely on the first mechanism of providing a +regulatory hint with an alpha2. For these drivers there is an additional +check that can be used to ensure compliance based on custom EEPROM +regulatory data. This additional check can be used by drivers by +registering on its struct wiphy a reg_notifier() callback. This notifier +is called when the core's regulatory domain has been changed. The driver +can use this to review the changes made and also review who made them +(driver, user, country IE) and determine what to allow based on its +internal EEPROM data. Devices drivers wishing to be capable of world +roaming should use this callback. More on world roaming will be +added to this document when its support is enabled. + +Device drivers who provide their own built regulatory domain +do not need a callback as the channels registered by them are +the only ones that will be allowed and therefore *additional* +channels cannot be enabled. + +Example code - drivers hinting an alpha2: +------------------------------------------ + +This example comes from the zd1211rw device driver. You can start +by having a mapping of your device's EEPROM country/regulatory +domain value to a specific alpha2 as follows:: + + static struct zd_reg_alpha2_map reg_alpha2_map[] = { + { ZD_REGDOMAIN_FCC, "US" }, + { ZD_REGDOMAIN_IC, "CA" }, + { ZD_REGDOMAIN_ETSI, "DE" }, /* Generic ETSI, use most restrictive */ + { ZD_REGDOMAIN_JAPAN, "JP" }, + { ZD_REGDOMAIN_JAPAN_ADD, "JP" }, + { ZD_REGDOMAIN_SPAIN, "ES" }, + { ZD_REGDOMAIN_FRANCE, "FR" }, + +Then you can define a routine to map your read EEPROM value to an alpha2, +as follows:: + + static int zd_reg2alpha2(u8 regdomain, char *alpha2) + { + unsigned int i; + struct zd_reg_alpha2_map *reg_map; + for (i = 0; i < ARRAY_SIZE(reg_alpha2_map); i++) { + reg_map = ®_alpha2_map[i]; + if (regdomain == reg_map->reg) { + alpha2[0] = reg_map->alpha2[0]; + alpha2[1] = reg_map->alpha2[1]; + return 0; + } + } + return 1; + } + +Lastly, you can then hint to the core of your discovered alpha2, if a match +was found. You need to do this after you have registered your wiphy. You +are expected to do this during initialization. + +:: + + r = zd_reg2alpha2(mac->regdomain, alpha2); + if (!r) + regulatory_hint(hw->wiphy, alpha2); + +Example code - drivers providing a built in regulatory domain: +-------------------------------------------------------------- + +[NOTE: This API is not currently available, it can be added when required] + +If you have regulatory information you can obtain from your +driver and you *need* to use this we let you build a regulatory domain +structure and pass it to the wireless core. To do this you should +kmalloc() a structure big enough to hold your regulatory domain +structure and you should then fill it with your data. Finally you simply +call regulatory_hint() with the regulatory domain structure in it. + +Below is a simple example, with a regulatory domain cached using the stack. +Your implementation may vary (read EEPROM cache instead, for example). + +Example cache of some regulatory domain:: + + struct ieee80211_regdomain mydriver_jp_regdom = { + .n_reg_rules = 3, + .alpha2 = "JP", + //.alpha2 = "99", /* If I have no alpha2 to map it to */ + .reg_rules = { + /* IEEE 802.11b/g, channels 1..14 */ + REG_RULE(2412-10, 2484+10, 40, 6, 20, 0), + /* IEEE 802.11a, channels 34..48 */ + REG_RULE(5170-10, 5240+10, 40, 6, 20, + NL80211_RRF_NO_IR), + /* IEEE 802.11a, channels 52..64 */ + REG_RULE(5260-10, 5320+10, 40, 6, 20, + NL80211_RRF_NO_IR| + NL80211_RRF_DFS), + } + }; + +Then in some part of your code after your wiphy has been registered:: + + struct ieee80211_regdomain *rd; + int size_of_regd; + int num_rules = mydriver_jp_regdom.n_reg_rules; + unsigned int i; + + size_of_regd = sizeof(struct ieee80211_regdomain) + + (num_rules * sizeof(struct ieee80211_reg_rule)); + + rd = kzalloc(size_of_regd, GFP_KERNEL); + if (!rd) + return -ENOMEM; + + memcpy(rd, &mydriver_jp_regdom, sizeof(struct ieee80211_regdomain)); + + for (i=0; i < num_rules; i++) + memcpy(&rd->reg_rules[i], + &mydriver_jp_regdom.reg_rules[i], + sizeof(struct ieee80211_reg_rule)); + regulatory_struct_hint(rd); + +Statically compiled regulatory database +--------------------------------------- + +When a database should be fixed into the kernel, it can be provided as a +firmware file at build time that is then linked into the kernel. diff --git a/Documentation/networking/representors.rst b/Documentation/networking/representors.rst new file mode 100644 index 0000000000..decb39c19b --- /dev/null +++ b/Documentation/networking/representors.rst @@ -0,0 +1,261 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================= +Network Function Representors +============================= + +This document describes the semantics and usage of representor netdevices, as +used to control internal switching on SmartNICs. For the closely-related port +representors on physical (multi-port) switches, see +:ref:`Documentation/networking/switchdev.rst <switchdev>`. + +Motivation +---------- + +Since the mid-2010s, network cards have started offering more complex +virtualisation capabilities than the legacy SR-IOV approach (with its simple +MAC/VLAN-based switching model) can support. This led to a desire to offload +software-defined networks (such as OpenVSwitch) to these NICs to specify the +network connectivity of each function. The resulting designs are variously +called SmartNICs or DPUs. + +Network function representors bring the standard Linux networking stack to +virtual switches and IOV devices. Just as each physical port of a Linux- +controlled switch has a separate netdev, so does each virtual port of a virtual +switch. +When the system boots, and before any offload is configured, all packets from +the virtual functions appear in the networking stack of the PF via the +representors. The PF can thus always communicate freely with the virtual +functions. +The PF can configure standard Linux forwarding between representors, the uplink +or any other netdev (routing, bridging, TC classifiers). + +Thus, a representor is both a control plane object (representing the function in +administrative commands) and a data plane object (one end of a virtual pipe). +As a virtual link endpoint, the representor can be configured like any other +netdevice; in some cases (e.g. link state) the representee will follow the +representor's configuration, while in others there are separate APIs to +configure the representee. + +Definitions +----------- + +This document uses the term "switchdev function" to refer to the PCIe function +which has administrative control over the virtual switch on the device. +Typically, this will be a PF, but conceivably a NIC could be configured to grant +these administrative privileges instead to a VF or SF (subfunction). +Depending on NIC design, a multi-port NIC might have a single switchdev function +for the whole device or might have a separate virtual switch, and hence +switchdev function, for each physical network port. +If the NIC supports nested switching, there might be separate switchdev +functions for each nested switch, in which case each switchdev function should +only create representors for the ports on the (sub-)switch it directly +administers. + +A "representee" is the object that a representor represents. So for example in +the case of a VF representor, the representee is the corresponding VF. + +What does a representor do? +--------------------------- + +A representor has three main roles. + +1. It is used to configure the network connection the representee sees, e.g. + link up/down, MTU, etc. For instance, bringing the representor + administratively UP should cause the representee to see a link up / carrier + on event. +2. It provides the slow path for traffic which does not hit any offloaded + fast-path rules in the virtual switch. Packets transmitted on the + representor netdevice should be delivered to the representee; packets + transmitted by the representee which fail to match any switching rule should + be received on the representor netdevice. (That is, there is a virtual pipe + connecting the representor to the representee, similar in concept to a veth + pair.) + This allows software switch implementations (such as OpenVSwitch or a Linux + bridge) to forward packets between representees and the rest of the network. +3. It acts as a handle by which switching rules (such as TC filters) can refer + to the representee, allowing these rules to be offloaded. + +The combination of 2) and 3) means that the behaviour (apart from performance) +should be the same whether a TC filter is offloaded or not. E.g. a TC rule +on a VF representor applies in software to packets received on that representor +netdevice, while in hardware offload it would apply to packets transmitted by +the representee VF. Conversely, a mirred egress redirect to a VF representor +corresponds in hardware to delivery directly to the representee VF. + +What functions should have a representor? +----------------------------------------- + +Essentially, for each virtual port on the device's internal switch, there +should be a representor. +Some vendors have chosen to omit representors for the uplink and the physical +network port, which can simplify usage (the uplink netdev becomes in effect the +physical port's representor) but does not generalise to devices with multiple +ports or uplinks. + +Thus, the following should all have representors: + + - VFs belonging to the switchdev function. + - Other PFs on the local PCIe controller, and any VFs belonging to them. + - PFs and VFs on external PCIe controllers on the device (e.g. for any embedded + System-on-Chip within the SmartNIC). + - PFs and VFs with other personalities, including network block devices (such + as a vDPA virtio-blk PF backed by remote/distributed storage), if (and only + if) their network access is implemented through a virtual switch port. [#]_ + Note that such functions can require a representor despite the representee + not having a netdev. + - Subfunctions (SFs) belonging to any of the above PFs or VFs, if they have + their own port on the switch (as opposed to using their parent PF's port). + - Any accelerators or plugins on the device whose interface to the network is + through a virtual switch port, even if they do not have a corresponding PCIe + PF or VF. + +This allows the entire switching behaviour of the NIC to be controlled through +representor TC rules. + +It is a common misunderstanding to conflate virtual ports with PCIe virtual +functions or their netdevs. While in simple cases there will be a 1:1 +correspondence between VF netdevices and VF representors, more advanced device +configurations may not follow this. +A PCIe function which does not have network access through the internal switch +(not even indirectly through the hardware implementation of whatever services +the function provides) should *not* have a representor (even if it has a +netdev). +Such a function has no switch virtual port for the representor to configure or +to be the other end of the virtual pipe. +The representor represents the virtual port, not the PCIe function nor the 'end +user' netdevice. + +.. [#] The concept here is that a hardware IP stack in the device performs the + translation between block DMA requests and network packets, so that only + network packets pass through the virtual port onto the switch. The network + access that the IP stack "sees" would then be configurable through tc rules; + e.g. its traffic might all be wrapped in a specific VLAN or VxLAN. However, + any needed configuration of the block device *qua* block device, not being a + networking entity, would not be appropriate for the representor and would + thus use some other channel such as devlink. + Contrast this with the case of a virtio-blk implementation which forwards the + DMA requests unchanged to another PF whose driver then initiates and + terminates IP traffic in software; in that case the DMA traffic would *not* + run over the virtual switch and the virtio-blk PF should thus *not* have a + representor. + +How are representors created? +----------------------------- + +The driver instance attached to the switchdev function should, for each virtual +port on the switch, create a pure-software netdevice which has some form of +in-kernel reference to the switchdev function's own netdevice or driver private +data (``netdev_priv()``). +This may be by enumerating ports at probe time, reacting dynamically to the +creation and destruction of ports at run time, or a combination of the two. + +The operations of the representor netdevice will generally involve acting +through the switchdev function. For example, ``ndo_start_xmit()`` might send +the packet through a hardware TX queue attached to the switchdev function, with +either packet metadata or queue configuration marking it for delivery to the +representee. + +How are representors identified? +-------------------------------- + +The representor netdevice should *not* directly refer to a PCIe device (e.g. +through ``net_dev->dev.parent`` / ``SET_NETDEV_DEV()``), either of the +representee or of the switchdev function. +Instead, the driver should use the ``SET_NETDEV_DEVLINK_PORT`` macro to +assign a devlink port instance to the netdevice before registering the +netdevice; the kernel uses the devlink port to provide the ``phys_switch_id`` +and ``phys_port_name`` sysfs nodes. +(Some legacy drivers implement ``ndo_get_port_parent_id()`` and +``ndo_get_phys_port_name()`` directly, but this is deprecated.) See +:ref:`Documentation/networking/devlink/devlink-port.rst <devlink_port>` for the +details of this API. + +It is expected that userland will use this information (e.g. through udev rules) +to construct an appropriately informative name or alias for the netdevice. For +instance if the switchdev function is ``eth4`` then a representor with a +``phys_port_name`` of ``p0pf1vf2`` might be renamed ``eth4pf1vf2rep``. + +There are as yet no established conventions for naming representors which do not +correspond to PCIe functions (e.g. accelerators and plugins). + +How do representors interact with TC rules? +------------------------------------------- + +Any TC rule on a representor applies (in software TC) to packets received by +that representor netdevice. Thus, if the delivery part of the rule corresponds +to another port on the virtual switch, the driver may choose to offload it to +hardware, applying it to packets transmitted by the representee. + +Similarly, since a TC mirred egress action targeting the representor would (in +software) send the packet through the representor (and thus indirectly deliver +it to the representee), hardware offload should interpret this as delivery to +the representee. + +As a simple example, if ``PORT_DEV`` is the physical port representor and +``REP_DEV`` is a VF representor, the following rules:: + + tc filter add dev $REP_DEV parent ffff: protocol ipv4 flower \ + action mirred egress redirect dev $PORT_DEV + tc filter add dev $PORT_DEV parent ffff: protocol ipv4 flower skip_sw \ + action mirred egress mirror dev $REP_DEV + +would mean that all IPv4 packets from the VF are sent out the physical port, and +all IPv4 packets received on the physical port are delivered to the VF in +addition to ``PORT_DEV``. (Note that without ``skip_sw`` on the second rule, +the VF would get two copies, as the packet reception on ``PORT_DEV`` would +trigger the TC rule again and mirror the packet to ``REP_DEV``.) + +On devices without separate port and uplink representors, ``PORT_DEV`` would +instead be the switchdev function's own uplink netdevice. + +Of course the rules can (if supported by the NIC) include packet-modifying +actions (e.g. VLAN push/pop), which should be performed by the virtual switch. + +Tunnel encapsulation and decapsulation are rather more complicated, as they +involve a third netdevice (a tunnel netdev operating in metadata mode, such as +a VxLAN device created with ``ip link add vxlan0 type vxlan external``) and +require an IP address to be bound to the underlay device (e.g. switchdev +function uplink netdev or port representor). TC rules such as:: + + tc filter add dev $REP_DEV parent ffff: flower \ + action tunnel_key set id $VNI src_ip $LOCAL_IP dst_ip $REMOTE_IP \ + dst_port 4789 \ + action mirred egress redirect dev vxlan0 + tc filter add dev vxlan0 parent ffff: flower enc_src_ip $REMOTE_IP \ + enc_dst_ip $LOCAL_IP enc_key_id $VNI enc_dst_port 4789 \ + action tunnel_key unset action mirred egress redirect dev $REP_DEV + +where ``LOCAL_IP`` is an IP address bound to ``PORT_DEV``, and ``REMOTE_IP`` is +another IP address on the same subnet, mean that packets sent by the VF should +be VxLAN encapsulated and sent out the physical port (the driver has to deduce +this by a route lookup of ``LOCAL_IP`` leading to ``PORT_DEV``, and also +perform an ARP/neighbour table lookup to find the MAC addresses to use in the +outer Ethernet frame), while UDP packets received on the physical port with UDP +port 4789 should be parsed as VxLAN and, if their VSID matches ``$VNI``, +decapsulated and forwarded to the VF. + +If this all seems complicated, just remember the 'golden rule' of TC offload: +the hardware should ensure the same final results as if the packets were +processed through the slow path, traversed software TC (except ignoring any +``skip_hw`` rules and applying any ``skip_sw`` rules) and were transmitted or +received through the representor netdevices. + +Configuring the representee's MAC +--------------------------------- + +The representee's link state is controlled through the representor. Setting the +representor administratively UP or DOWN should cause carrier ON or OFF at the +representee. + +Setting an MTU on the representor should cause that same MTU to be reported to +the representee. +(On hardware that allows configuring separate and distinct MTU and MRU values, +the representor MTU should correspond to the representee's MRU and vice-versa.) + +Currently there is no way to use the representor to set the station permanent +MAC address of the representee; other methods available to do this include: + + - legacy SR-IOV (``ip link set DEVICE vf NUM mac LLADDR``) + - devlink port function (see **devlink-port(8)** and + :ref:`Documentation/networking/devlink/devlink-port.rst <devlink_port>`) diff --git a/Documentation/networking/rxrpc.rst b/Documentation/networking/rxrpc.rst new file mode 100644 index 0000000000..e807e18ba3 --- /dev/null +++ b/Documentation/networking/rxrpc.rst @@ -0,0 +1,1174 @@ +.. SPDX-License-Identifier: GPL-2.0 + +====================== +RxRPC Network Protocol +====================== + +The RxRPC protocol driver provides a reliable two-phase transport on top of UDP +that can be used to perform RxRPC remote operations. This is done over sockets +of AF_RXRPC family, using sendmsg() and recvmsg() with control data to send and +receive data, aborts and errors. + +Contents of this document: + + (#) Overview. + + (#) RxRPC protocol summary. + + (#) AF_RXRPC driver model. + + (#) Control messages. + + (#) Socket options. + + (#) Security. + + (#) Example client usage. + + (#) Example server usage. + + (#) AF_RXRPC kernel interface. + + (#) Configurable parameters. + + +Overview +======== + +RxRPC is a two-layer protocol. There is a session layer which provides +reliable virtual connections using UDP over IPv4 (or IPv6) as the transport +layer, but implements a real network protocol; and there's the presentation +layer which renders structured data to binary blobs and back again using XDR +(as does SunRPC):: + + +-------------+ + | Application | + +-------------+ + | XDR | Presentation + +-------------+ + | RxRPC | Session + +-------------+ + | UDP | Transport + +-------------+ + + +AF_RXRPC provides: + + (1) Part of an RxRPC facility for both kernel and userspace applications by + making the session part of it a Linux network protocol (AF_RXRPC). + + (2) A two-phase protocol. The client transmits a blob (the request) and then + receives a blob (the reply), and the server receives the request and then + transmits the reply. + + (3) Retention of the reusable bits of the transport system set up for one call + to speed up subsequent calls. + + (4) A secure protocol, using the Linux kernel's key retention facility to + manage security on the client end. The server end must of necessity be + more active in security negotiations. + +AF_RXRPC does not provide XDR marshalling/presentation facilities. That is +left to the application. AF_RXRPC only deals in blobs. Even the operation ID +is just the first four bytes of the request blob, and as such is beyond the +kernel's interest. + + +Sockets of AF_RXRPC family are: + + (1) created as type SOCK_DGRAM; + + (2) provided with a protocol of the type of underlying transport they're going + to use - currently only PF_INET is supported. + + +The Andrew File System (AFS) is an example of an application that uses this and +that has both kernel (filesystem) and userspace (utility) components. + + +RxRPC Protocol Summary +====================== + +An overview of the RxRPC protocol: + + (#) RxRPC sits on top of another networking protocol (UDP is the only option + currently), and uses this to provide network transport. UDP ports, for + example, provide transport endpoints. + + (#) RxRPC supports multiple virtual "connections" from any given transport + endpoint, thus allowing the endpoints to be shared, even to the same + remote endpoint. + + (#) Each connection goes to a particular "service". A connection may not go + to multiple services. A service may be considered the RxRPC equivalent of + a port number. AF_RXRPC permits multiple services to share an endpoint. + + (#) Client-originating packets are marked, thus a transport endpoint can be + shared between client and server connections (connections have a + direction). + + (#) Up to a billion connections may be supported concurrently between one + local transport endpoint and one service on one remote endpoint. An RxRPC + connection is described by seven numbers:: + + Local address } + Local port } Transport (UDP) address + Remote address } + Remote port } + Direction + Connection ID + Service ID + + (#) Each RxRPC operation is a "call". A connection may make up to four + billion calls, but only up to four calls may be in progress on a + connection at any one time. + + (#) Calls are two-phase and asymmetric: the client sends its request data, + which the service receives; then the service transmits the reply data + which the client receives. + + (#) The data blobs are of indefinite size, the end of a phase is marked with a + flag in the packet. The number of packets of data making up one blob may + not exceed 4 billion, however, as this would cause the sequence number to + wrap. + + (#) The first four bytes of the request data are the service operation ID. + + (#) Security is negotiated on a per-connection basis. The connection is + initiated by the first data packet on it arriving. If security is + requested, the server then issues a "challenge" and then the client + replies with a "response". If the response is successful, the security is + set for the lifetime of that connection, and all subsequent calls made + upon it use that same security. In the event that the server lets a + connection lapse before the client, the security will be renegotiated if + the client uses the connection again. + + (#) Calls use ACK packets to handle reliability. Data packets are also + explicitly sequenced per call. + + (#) There are two types of positive acknowledgment: hard-ACKs and soft-ACKs. + A hard-ACK indicates to the far side that all the data received to a point + has been received and processed; a soft-ACK indicates that the data has + been received but may yet be discarded and re-requested. The sender may + not discard any transmittable packets until they've been hard-ACK'd. + + (#) Reception of a reply data packet implicitly hard-ACK's all the data + packets that make up the request. + + (#) An call is complete when the request has been sent, the reply has been + received and the final hard-ACK on the last packet of the reply has + reached the server. + + (#) An call may be aborted by either end at any time up to its completion. + + +AF_RXRPC Driver Model +===================== + +About the AF_RXRPC driver: + + (#) The AF_RXRPC protocol transparently uses internal sockets of the transport + protocol to represent transport endpoints. + + (#) AF_RXRPC sockets map onto RxRPC connection bundles. Actual RxRPC + connections are handled transparently. One client socket may be used to + make multiple simultaneous calls to the same service. One server socket + may handle calls from many clients. + + (#) Additional parallel client connections will be initiated to support extra + concurrent calls, up to a tunable limit. + + (#) Each connection is retained for a certain amount of time [tunable] after + the last call currently using it has completed in case a new call is made + that could reuse it. + + (#) Each internal UDP socket is retained [tunable] for a certain amount of + time [tunable] after the last connection using it discarded, in case a new + connection is made that could use it. + + (#) A client-side connection is only shared between calls if they have + the same key struct describing their security (and assuming the calls + would otherwise share the connection). Non-secured calls would also be + able to share connections with each other. + + (#) A server-side connection is shared if the client says it is. + + (#) ACK'ing is handled by the protocol driver automatically, including ping + replying. + + (#) SO_KEEPALIVE automatically pings the other side to keep the connection + alive [TODO]. + + (#) If an ICMP error is received, all calls affected by that error will be + aborted with an appropriate network error passed through recvmsg(). + + +Interaction with the user of the RxRPC socket: + + (#) A socket is made into a server socket by binding an address with a + non-zero service ID. + + (#) In the client, sending a request is achieved with one or more sendmsgs, + followed by the reply being received with one or more recvmsgs. + + (#) The first sendmsg for a request to be sent from a client contains a tag to + be used in all other sendmsgs or recvmsgs associated with that call. The + tag is carried in the control data. + + (#) connect() is used to supply a default destination address for a client + socket. This may be overridden by supplying an alternate address to the + first sendmsg() of a call (struct msghdr::msg_name). + + (#) If connect() is called on an unbound client, a random local port will + bound before the operation takes place. + + (#) A server socket may also be used to make client calls. To do this, the + first sendmsg() of the call must specify the target address. The server's + transport endpoint is used to send the packets. + + (#) Once the application has received the last message associated with a call, + the tag is guaranteed not to be seen again, and so it can be used to pin + client resources. A new call can then be initiated with the same tag + without fear of interference. + + (#) In the server, a request is received with one or more recvmsgs, then the + the reply is transmitted with one or more sendmsgs, and then the final ACK + is received with a last recvmsg. + + (#) When sending data for a call, sendmsg is given MSG_MORE if there's more + data to come on that call. + + (#) When receiving data for a call, recvmsg flags MSG_MORE if there's more + data to come for that call. + + (#) When receiving data or messages for a call, MSG_EOR is flagged by recvmsg + to indicate the terminal message for that call. + + (#) A call may be aborted by adding an abort control message to the control + data. Issuing an abort terminates the kernel's use of that call's tag. + Any messages waiting in the receive queue for that call will be discarded. + + (#) Aborts, busy notifications and challenge packets are delivered by recvmsg, + and control data messages will be set to indicate the context. Receiving + an abort or a busy message terminates the kernel's use of that call's tag. + + (#) The control data part of the msghdr struct is used for a number of things: + + (#) The tag of the intended or affected call. + + (#) Sending or receiving errors, aborts and busy notifications. + + (#) Notifications of incoming calls. + + (#) Sending debug requests and receiving debug replies [TODO]. + + (#) When the kernel has received and set up an incoming call, it sends a + message to server application to let it know there's a new call awaiting + its acceptance [recvmsg reports a special control message]. The server + application then uses sendmsg to assign a tag to the new call. Once that + is done, the first part of the request data will be delivered by recvmsg. + + (#) The server application has to provide the server socket with a keyring of + secret keys corresponding to the security types it permits. When a secure + connection is being set up, the kernel looks up the appropriate secret key + in the keyring and then sends a challenge packet to the client and + receives a response packet. The kernel then checks the authorisation of + the packet and either aborts the connection or sets up the security. + + (#) The name of the key a client will use to secure its communications is + nominated by a socket option. + + +Notes on sendmsg: + + (#) MSG_WAITALL can be set to tell sendmsg to ignore signals if the peer is + making progress at accepting packets within a reasonable time such that we + manage to queue up all the data for transmission. This requires the + client to accept at least one packet per 2*RTT time period. + + If this isn't set, sendmsg() will return immediately, either returning + EINTR/ERESTARTSYS if nothing was consumed or returning the amount of data + consumed. + + +Notes on recvmsg: + + (#) If there's a sequence of data messages belonging to a particular call on + the receive queue, then recvmsg will keep working through them until: + + (a) it meets the end of that call's received data, + + (b) it meets a non-data message, + + (c) it meets a message belonging to a different call, or + + (d) it fills the user buffer. + + If recvmsg is called in blocking mode, it will keep sleeping, awaiting the + reception of further data, until one of the above four conditions is met. + + (2) MSG_PEEK operates similarly, but will return immediately if it has put any + data in the buffer rather than sleeping until it can fill the buffer. + + (3) If a data message is only partially consumed in filling a user buffer, + then the remainder of that message will be left on the front of the queue + for the next taker. MSG_TRUNC will never be flagged. + + (4) If there is more data to be had on a call (it hasn't copied the last byte + of the last data message in that phase yet), then MSG_MORE will be + flagged. + + +Control Messages +================ + +AF_RXRPC makes use of control messages in sendmsg() and recvmsg() to multiplex +calls, to invoke certain actions and to report certain conditions. These are: + + ======================= === =========== =============================== + MESSAGE ID SRT DATA MEANING + ======================= === =========== =============================== + RXRPC_USER_CALL_ID sr- User ID App's call specifier + RXRPC_ABORT srt Abort code Abort code to issue/received + RXRPC_ACK -rt n/a Final ACK received + RXRPC_NET_ERROR -rt error num Network error on call + RXRPC_BUSY -rt n/a Call rejected (server busy) + RXRPC_LOCAL_ERROR -rt error num Local error encountered + RXRPC_NEW_CALL -r- n/a New call received + RXRPC_ACCEPT s-- n/a Accept new call + RXRPC_EXCLUSIVE_CALL s-- n/a Make an exclusive client call + RXRPC_UPGRADE_SERVICE s-- n/a Client call can be upgraded + RXRPC_TX_LENGTH s-- data len Total length of Tx data + ======================= === =========== =============================== + + (SRT = usable in Sendmsg / delivered by Recvmsg / Terminal message) + + (#) RXRPC_USER_CALL_ID + + This is used to indicate the application's call ID. It's an unsigned long + that the app specifies in the client by attaching it to the first data + message or in the server by passing it in association with an RXRPC_ACCEPT + message. recvmsg() passes it in conjunction with all messages except + those of the RXRPC_NEW_CALL message. + + (#) RXRPC_ABORT + + This is can be used by an application to abort a call by passing it to + sendmsg, or it can be delivered by recvmsg to indicate a remote abort was + received. Either way, it must be associated with an RXRPC_USER_CALL_ID to + specify the call affected. If an abort is being sent, then error EBADSLT + will be returned if there is no call with that user ID. + + (#) RXRPC_ACK + + This is delivered to a server application to indicate that the final ACK + of a call was received from the client. It will be associated with an + RXRPC_USER_CALL_ID to indicate the call that's now complete. + + (#) RXRPC_NET_ERROR + + This is delivered to an application to indicate that an ICMP error message + was encountered in the process of trying to talk to the peer. An + errno-class integer value will be included in the control message data + indicating the problem, and an RXRPC_USER_CALL_ID will indicate the call + affected. + + (#) RXRPC_BUSY + + This is delivered to a client application to indicate that a call was + rejected by the server due to the server being busy. It will be + associated with an RXRPC_USER_CALL_ID to indicate the rejected call. + + (#) RXRPC_LOCAL_ERROR + + This is delivered to an application to indicate that a local error was + encountered and that a call has been aborted because of it. An + errno-class integer value will be included in the control message data + indicating the problem, and an RXRPC_USER_CALL_ID will indicate the call + affected. + + (#) RXRPC_NEW_CALL + + This is delivered to indicate to a server application that a new call has + arrived and is awaiting acceptance. No user ID is associated with this, + as a user ID must subsequently be assigned by doing an RXRPC_ACCEPT. + + (#) RXRPC_ACCEPT + + This is used by a server application to attempt to accept a call and + assign it a user ID. It should be associated with an RXRPC_USER_CALL_ID + to indicate the user ID to be assigned. If there is no call to be + accepted (it may have timed out, been aborted, etc.), then sendmsg will + return error ENODATA. If the user ID is already in use by another call, + then error EBADSLT will be returned. + + (#) RXRPC_EXCLUSIVE_CALL + + This is used to indicate that a client call should be made on a one-off + connection. The connection is discarded once the call has terminated. + + (#) RXRPC_UPGRADE_SERVICE + + This is used to make a client call to probe if the specified service ID + may be upgraded by the server. The caller must check msg_name returned to + recvmsg() for the service ID actually in use. The operation probed must + be one that takes the same arguments in both services. + + Once this has been used to establish the upgrade capability (or lack + thereof) of the server, the service ID returned should be used for all + future communication to that server and RXRPC_UPGRADE_SERVICE should no + longer be set. + + (#) RXRPC_TX_LENGTH + + This is used to inform the kernel of the total amount of data that is + going to be transmitted by a call (whether in a client request or a + service response). If given, it allows the kernel to encrypt from the + userspace buffer directly to the packet buffers, rather than copying into + the buffer and then encrypting in place. This may only be given with the + first sendmsg() providing data for a call. EMSGSIZE will be generated if + the amount of data actually given is different. + + This takes a parameter of __s64 type that indicates how much will be + transmitted. This may not be less than zero. + +The symbol RXRPC__SUPPORTED is defined as one more than the highest control +message type supported. At run time this can be queried by means of the +RXRPC_SUPPORTED_CMSG socket option (see below). + + +============== +SOCKET OPTIONS +============== + +AF_RXRPC sockets support a few socket options at the SOL_RXRPC level: + + (#) RXRPC_SECURITY_KEY + + This is used to specify the description of the key to be used. The key is + extracted from the calling process's keyrings with request_key() and + should be of "rxrpc" type. + + The optval pointer points to the description string, and optlen indicates + how long the string is, without the NUL terminator. + + (#) RXRPC_SECURITY_KEYRING + + Similar to above but specifies a keyring of server secret keys to use (key + type "keyring"). See the "Security" section. + + (#) RXRPC_EXCLUSIVE_CONNECTION + + This is used to request that new connections should be used for each call + made subsequently on this socket. optval should be NULL and optlen 0. + + (#) RXRPC_MIN_SECURITY_LEVEL + + This is used to specify the minimum security level required for calls on + this socket. optval must point to an int containing one of the following + values: + + (a) RXRPC_SECURITY_PLAIN + + Encrypted checksum only. + + (b) RXRPC_SECURITY_AUTH + + Encrypted checksum plus packet padded and first eight bytes of packet + encrypted - which includes the actual packet length. + + (c) RXRPC_SECURITY_ENCRYPT + + Encrypted checksum plus entire packet padded and encrypted, including + actual packet length. + + (#) RXRPC_UPGRADEABLE_SERVICE + + This is used to indicate that a service socket with two bindings may + upgrade one bound service to the other if requested by the client. optval + must point to an array of two unsigned short ints. The first is the + service ID to upgrade from and the second the service ID to upgrade to. + + (#) RXRPC_SUPPORTED_CMSG + + This is a read-only option that writes an int into the buffer indicating + the highest control message type supported. + + +======== +SECURITY +======== + +Currently, only the kerberos 4 equivalent protocol has been implemented +(security index 2 - rxkad). This requires the rxkad module to be loaded and, +on the client, tickets of the appropriate type to be obtained from the AFS +kaserver or the kerberos server and installed as "rxrpc" type keys. This is +normally done using the klog program. An example simple klog program can be +found at: + + http://people.redhat.com/~dhowells/rxrpc/klog.c + +The payload provided to add_key() on the client should be of the following +form:: + + struct rxrpc_key_sec2_v1 { + uint16_t security_index; /* 2 */ + uint16_t ticket_length; /* length of ticket[] */ + uint32_t expiry; /* time at which expires */ + uint8_t kvno; /* key version number */ + uint8_t __pad[3]; + uint8_t session_key[8]; /* DES session key */ + uint8_t ticket[0]; /* the encrypted ticket */ + }; + +Where the ticket blob is just appended to the above structure. + + +For the server, keys of type "rxrpc_s" must be made available to the server. +They have a description of "<serviceID>:<securityIndex>" (eg: "52:2" for an +rxkad key for the AFS VL service). When such a key is created, it should be +given the server's secret key as the instantiation data (see the example +below). + + add_key("rxrpc_s", "52:2", secret_key, 8, keyring); + +A keyring is passed to the server socket by naming it in a sockopt. The server +socket then looks the server secret keys up in this keyring when secure +incoming connections are made. This can be seen in an example program that can +be found at: + + http://people.redhat.com/~dhowells/rxrpc/listen.c + + +==================== +EXAMPLE CLIENT USAGE +==================== + +A client would issue an operation by: + + (1) An RxRPC socket is set up by:: + + client = socket(AF_RXRPC, SOCK_DGRAM, PF_INET); + + Where the third parameter indicates the protocol family of the transport + socket used - usually IPv4 but it can also be IPv6 [TODO]. + + (2) A local address can optionally be bound:: + + struct sockaddr_rxrpc srx = { + .srx_family = AF_RXRPC, + .srx_service = 0, /* we're a client */ + .transport_type = SOCK_DGRAM, /* type of transport socket */ + .transport.sin_family = AF_INET, + .transport.sin_port = htons(7000), /* AFS callback */ + .transport.sin_address = 0, /* all local interfaces */ + }; + bind(client, &srx, sizeof(srx)); + + This specifies the local UDP port to be used. If not given, a random + non-privileged port will be used. A UDP port may be shared between + several unrelated RxRPC sockets. Security is handled on a basis of + per-RxRPC virtual connection. + + (3) The security is set:: + + const char *key = "AFS:cambridge.redhat.com"; + setsockopt(client, SOL_RXRPC, RXRPC_SECURITY_KEY, key, strlen(key)); + + This issues a request_key() to get the key representing the security + context. The minimum security level can be set:: + + unsigned int sec = RXRPC_SECURITY_ENCRYPT; + setsockopt(client, SOL_RXRPC, RXRPC_MIN_SECURITY_LEVEL, + &sec, sizeof(sec)); + + (4) The server to be contacted can then be specified (alternatively this can + be done through sendmsg):: + + struct sockaddr_rxrpc srx = { + .srx_family = AF_RXRPC, + .srx_service = VL_SERVICE_ID, + .transport_type = SOCK_DGRAM, /* type of transport socket */ + .transport.sin_family = AF_INET, + .transport.sin_port = htons(7005), /* AFS volume manager */ + .transport.sin_address = ..., + }; + connect(client, &srx, sizeof(srx)); + + (5) The request data should then be posted to the server socket using a series + of sendmsg() calls, each with the following control message attached: + + ================== =================================== + RXRPC_USER_CALL_ID specifies the user ID for this call + ================== =================================== + + MSG_MORE should be set in msghdr::msg_flags on all but the last part of + the request. Multiple requests may be made simultaneously. + + An RXRPC_TX_LENGTH control message can also be specified on the first + sendmsg() call. + + If a call is intended to go to a destination other than the default + specified through connect(), then msghdr::msg_name should be set on the + first request message of that call. + + (6) The reply data will then be posted to the server socket for recvmsg() to + pick up. MSG_MORE will be flagged by recvmsg() if there's more reply data + for a particular call to be read. MSG_EOR will be set on the terminal + read for a call. + + All data will be delivered with the following control message attached: + + RXRPC_USER_CALL_ID - specifies the user ID for this call + + If an abort or error occurred, this will be returned in the control data + buffer instead, and MSG_EOR will be flagged to indicate the end of that + call. + +A client may ask for a service ID it knows and ask that this be upgraded to a +better service if one is available by supplying RXRPC_UPGRADE_SERVICE on the +first sendmsg() of a call. The client should then check srx_service in the +msg_name filled in by recvmsg() when collecting the result. srx_service will +hold the same value as given to sendmsg() if the upgrade request was ignored by +the service - otherwise it will be altered to indicate the service ID the +server upgraded to. Note that the upgraded service ID is chosen by the server. +The caller has to wait until it sees the service ID in the reply before sending +any more calls (further calls to the same destination will be blocked until the +probe is concluded). + + +Example Server Usage +==================== + +A server would be set up to accept operations in the following manner: + + (1) An RxRPC socket is created by:: + + server = socket(AF_RXRPC, SOCK_DGRAM, PF_INET); + + Where the third parameter indicates the address type of the transport + socket used - usually IPv4. + + (2) Security is set up if desired by giving the socket a keyring with server + secret keys in it:: + + keyring = add_key("keyring", "AFSkeys", NULL, 0, + KEY_SPEC_PROCESS_KEYRING); + + const char secret_key[8] = { + 0xa7, 0x83, 0x8a, 0xcb, 0xc7, 0x83, 0xec, 0x94 }; + add_key("rxrpc_s", "52:2", secret_key, 8, keyring); + + setsockopt(server, SOL_RXRPC, RXRPC_SECURITY_KEYRING, "AFSkeys", 7); + + The keyring can be manipulated after it has been given to the socket. This + permits the server to add more keys, replace keys, etc. while it is live. + + (3) A local address must then be bound:: + + struct sockaddr_rxrpc srx = { + .srx_family = AF_RXRPC, + .srx_service = VL_SERVICE_ID, /* RxRPC service ID */ + .transport_type = SOCK_DGRAM, /* type of transport socket */ + .transport.sin_family = AF_INET, + .transport.sin_port = htons(7000), /* AFS callback */ + .transport.sin_address = 0, /* all local interfaces */ + }; + bind(server, &srx, sizeof(srx)); + + More than one service ID may be bound to a socket, provided the transport + parameters are the same. The limit is currently two. To do this, bind() + should be called twice. + + (4) If service upgrading is required, first two service IDs must have been + bound and then the following option must be set:: + + unsigned short service_ids[2] = { from_ID, to_ID }; + setsockopt(server, SOL_RXRPC, RXRPC_UPGRADEABLE_SERVICE, + service_ids, sizeof(service_ids)); + + This will automatically upgrade connections on service from_ID to service + to_ID if they request it. This will be reflected in msg_name obtained + through recvmsg() when the request data is delivered to userspace. + + (5) The server is then set to listen out for incoming calls:: + + listen(server, 100); + + (6) The kernel notifies the server of pending incoming connections by sending + it a message for each. This is received with recvmsg() on the server + socket. It has no data, and has a single dataless control message + attached:: + + RXRPC_NEW_CALL + + The address that can be passed back by recvmsg() at this point should be + ignored since the call for which the message was posted may have gone by + the time it is accepted - in which case the first call still on the queue + will be accepted. + + (7) The server then accepts the new call by issuing a sendmsg() with two + pieces of control data and no actual data: + + ================== ============================== + RXRPC_ACCEPT indicate connection acceptance + RXRPC_USER_CALL_ID specify user ID for this call + ================== ============================== + + (8) The first request data packet will then be posted to the server socket for + recvmsg() to pick up. At that point, the RxRPC address for the call can + be read from the address fields in the msghdr struct. + + Subsequent request data will be posted to the server socket for recvmsg() + to collect as it arrives. All but the last piece of the request data will + be delivered with MSG_MORE flagged. + + All data will be delivered with the following control message attached: + + + ================== =================================== + RXRPC_USER_CALL_ID specifies the user ID for this call + ================== =================================== + + (9) The reply data should then be posted to the server socket using a series + of sendmsg() calls, each with the following control messages attached: + + ================== =================================== + RXRPC_USER_CALL_ID specifies the user ID for this call + ================== =================================== + + MSG_MORE should be set in msghdr::msg_flags on all but the last message + for a particular call. + +(10) The final ACK from the client will be posted for retrieval by recvmsg() + when it is received. It will take the form of a dataless message with two + control messages attached: + + ================== =================================== + RXRPC_USER_CALL_ID specifies the user ID for this call + RXRPC_ACK indicates final ACK (no data) + ================== =================================== + + MSG_EOR will be flagged to indicate that this is the final message for + this call. + +(11) Up to the point the final packet of reply data is sent, the call can be + aborted by calling sendmsg() with a dataless message with the following + control messages attached: + + ================== =================================== + RXRPC_USER_CALL_ID specifies the user ID for this call + RXRPC_ABORT indicates abort code (4 byte data) + ================== =================================== + + Any packets waiting in the socket's receive queue will be discarded if + this is issued. + +Note that all the communications for a particular service take place through +the one server socket, using control messages on sendmsg() and recvmsg() to +determine the call affected. + + +AF_RXRPC Kernel Interface +========================= + +The AF_RXRPC module also provides an interface for use by in-kernel utilities +such as the AFS filesystem. This permits such a utility to: + + (1) Use different keys directly on individual client calls on one socket + rather than having to open a whole slew of sockets, one for each key it + might want to use. + + (2) Avoid having RxRPC call request_key() at the point of issue of a call or + opening of a socket. Instead the utility is responsible for requesting a + key at the appropriate point. AFS, for instance, would do this during VFS + operations such as open() or unlink(). The key is then handed through + when the call is initiated. + + (3) Request the use of something other than GFP_KERNEL to allocate memory. + + (4) Avoid the overhead of using the recvmsg() call. RxRPC messages can be + intercepted before they get put into the socket Rx queue and the socket + buffers manipulated directly. + +To use the RxRPC facility, a kernel utility must still open an AF_RXRPC socket, +bind an address as appropriate and listen if it's to be a server socket, but +then it passes this to the kernel interface functions. + +The kernel interface functions are as follows: + + (#) Begin a new client call:: + + struct rxrpc_call * + rxrpc_kernel_begin_call(struct socket *sock, + struct sockaddr_rxrpc *srx, + struct key *key, + unsigned long user_call_ID, + s64 tx_total_len, + gfp_t gfp, + rxrpc_notify_rx_t notify_rx, + bool upgrade, + bool intr, + unsigned int debug_id); + + This allocates the infrastructure to make a new RxRPC call and assigns + call and connection numbers. The call will be made on the UDP port that + the socket is bound to. The call will go to the destination address of a + connected client socket unless an alternative is supplied (srx is + non-NULL). + + If a key is supplied then this will be used to secure the call instead of + the key bound to the socket with the RXRPC_SECURITY_KEY sockopt. Calls + secured in this way will still share connections if at all possible. + + The user_call_ID is equivalent to that supplied to sendmsg() in the + control data buffer. It is entirely feasible to use this to point to a + kernel data structure. + + tx_total_len is the amount of data the caller is intending to transmit + with this call (or -1 if unknown at this point). Setting the data size + allows the kernel to encrypt directly to the packet buffers, thereby + saving a copy. The value may not be less than -1. + + notify_rx is a pointer to a function to be called when events such as + incoming data packets or remote aborts happen. + + upgrade should be set to true if a client operation should request that + the server upgrade the service to a better one. The resultant service ID + is returned by rxrpc_kernel_recv_data(). + + intr should be set to true if the call should be interruptible. If this + is not set, this function may not return until a channel has been + allocated; if it is set, the function may return -ERESTARTSYS. + + debug_id is the call debugging ID to be used for tracing. This can be + obtained by atomically incrementing rxrpc_debug_id. + + If this function is successful, an opaque reference to the RxRPC call is + returned. The caller now holds a reference on this and it must be + properly ended. + + (#) Shut down a client call:: + + void rxrpc_kernel_shutdown_call(struct socket *sock, + struct rxrpc_call *call); + + This is used to shut down a previously begun call. The user_call_ID is + expunged from AF_RXRPC's knowledge and will not be seen again in + association with the specified call. + + (#) Release the ref on a client call:: + + void rxrpc_kernel_put_call(struct socket *sock, + struct rxrpc_call *call); + + This is used to release the caller's ref on an rxrpc call. + + (#) Send data through a call:: + + typedef void (*rxrpc_notify_end_tx_t)(struct sock *sk, + unsigned long user_call_ID, + struct sk_buff *skb); + + int rxrpc_kernel_send_data(struct socket *sock, + struct rxrpc_call *call, + struct msghdr *msg, + size_t len, + rxrpc_notify_end_tx_t notify_end_rx); + + This is used to supply either the request part of a client call or the + reply part of a server call. msg.msg_iovlen and msg.msg_iov specify the + data buffers to be used. msg_iov may not be NULL and must point + exclusively to in-kernel virtual addresses. msg.msg_flags may be given + MSG_MORE if there will be subsequent data sends for this call. + + The msg must not specify a destination address, control data or any flags + other than MSG_MORE. len is the total amount of data to transmit. + + notify_end_rx can be NULL or it can be used to specify a function to be + called when the call changes state to end the Tx phase. This function is + called with a spinlock held to prevent the last DATA packet from being + transmitted until the function returns. + + (#) Receive data from a call:: + + int rxrpc_kernel_recv_data(struct socket *sock, + struct rxrpc_call *call, + void *buf, + size_t size, + size_t *_offset, + bool want_more, + u32 *_abort, + u16 *_service) + + This is used to receive data from either the reply part of a client call + or the request part of a service call. buf and size specify how much + data is desired and where to store it. *_offset is added on to buf and + subtracted from size internally; the amount copied into the buffer is + added to *_offset before returning. + + want_more should be true if further data will be required after this is + satisfied and false if this is the last item of the receive phase. + + There are three normal returns: 0 if the buffer was filled and want_more + was true; 1 if the buffer was filled, the last DATA packet has been + emptied and want_more was false; and -EAGAIN if the function needs to be + called again. + + If the last DATA packet is processed but the buffer contains less than + the amount requested, EBADMSG is returned. If want_more wasn't set, but + more data was available, EMSGSIZE is returned. + + If a remote ABORT is detected, the abort code received will be stored in + ``*_abort`` and ECONNABORTED will be returned. + + The service ID that the call ended up with is returned into *_service. + This can be used to see if a call got a service upgrade. + + (#) Abort a call?? + + :: + + void rxrpc_kernel_abort_call(struct socket *sock, + struct rxrpc_call *call, + u32 abort_code); + + This is used to abort a call if it's still in an abortable state. The + abort code specified will be placed in the ABORT message sent. + + (#) Intercept received RxRPC messages:: + + typedef void (*rxrpc_interceptor_t)(struct sock *sk, + unsigned long user_call_ID, + struct sk_buff *skb); + + void + rxrpc_kernel_intercept_rx_messages(struct socket *sock, + rxrpc_interceptor_t interceptor); + + This installs an interceptor function on the specified AF_RXRPC socket. + All messages that would otherwise wind up in the socket's Rx queue are + then diverted to this function. Note that care must be taken to process + the messages in the right order to maintain DATA message sequentiality. + + The interceptor function itself is provided with the address of the socket + and handling the incoming message, the ID assigned by the kernel utility + to the call and the socket buffer containing the message. + + The skb->mark field indicates the type of message: + + =============================== ======================================= + Mark Meaning + =============================== ======================================= + RXRPC_SKB_MARK_DATA Data message + RXRPC_SKB_MARK_FINAL_ACK Final ACK received for an incoming call + RXRPC_SKB_MARK_BUSY Client call rejected as server busy + RXRPC_SKB_MARK_REMOTE_ABORT Call aborted by peer + RXRPC_SKB_MARK_NET_ERROR Network error detected + RXRPC_SKB_MARK_LOCAL_ERROR Local error encountered + RXRPC_SKB_MARK_NEW_CALL New incoming call awaiting acceptance + =============================== ======================================= + + The remote abort message can be probed with rxrpc_kernel_get_abort_code(). + The two error messages can be probed with rxrpc_kernel_get_error_number(). + A new call can be accepted with rxrpc_kernel_accept_call(). + + Data messages can have their contents extracted with the usual bunch of + socket buffer manipulation functions. A data message can be determined to + be the last one in a sequence with rxrpc_kernel_is_data_last(). When a + data message has been used up, rxrpc_kernel_data_consumed() should be + called on it. + + Messages should be handled to rxrpc_kernel_free_skb() to dispose of. It + is possible to get extra refs on all types of message for later freeing, + but this may pin the state of a call until the message is finally freed. + + (#) Accept an incoming call:: + + struct rxrpc_call * + rxrpc_kernel_accept_call(struct socket *sock, + unsigned long user_call_ID); + + This is used to accept an incoming call and to assign it a call ID. This + function is similar to rxrpc_kernel_begin_call() and calls accepted must + be ended in the same way. + + If this function is successful, an opaque reference to the RxRPC call is + returned. The caller now holds a reference on this and it must be + properly ended. + + (#) Reject an incoming call:: + + int rxrpc_kernel_reject_call(struct socket *sock); + + This is used to reject the first incoming call on the socket's queue with + a BUSY message. -ENODATA is returned if there were no incoming calls. + Other errors may be returned if the call had been aborted (-ECONNABORTED) + or had timed out (-ETIME). + + (#) Allocate a null key for doing anonymous security:: + + struct key *rxrpc_get_null_key(const char *keyname); + + This is used to allocate a null RxRPC key that can be used to indicate + anonymous security for a particular domain. + + (#) Get the peer address of a call:: + + void rxrpc_kernel_get_peer(struct socket *sock, struct rxrpc_call *call, + struct sockaddr_rxrpc *_srx); + + This is used to find the remote peer address of a call. + + (#) Set the total transmit data size on a call:: + + void rxrpc_kernel_set_tx_length(struct socket *sock, + struct rxrpc_call *call, + s64 tx_total_len); + + This sets the amount of data that the caller is intending to transmit on a + call. It's intended to be used for setting the reply size as the request + size should be set when the call is begun. tx_total_len may not be less + than zero. + + (#) Get call RTT:: + + u64 rxrpc_kernel_get_rtt(struct socket *sock, struct rxrpc_call *call); + + Get the RTT time to the peer in use by a call. The value returned is in + nanoseconds. + + (#) Check call still alive:: + + bool rxrpc_kernel_check_life(struct socket *sock, + struct rxrpc_call *call, + u32 *_life); + void rxrpc_kernel_probe_life(struct socket *sock, + struct rxrpc_call *call); + + The first function passes back in ``*_life`` a number that is updated when + ACKs are received from the peer (notably including PING RESPONSE ACKs + which we can elicit by sending PING ACKs to see if the call still exists + on the server). The caller should compare the numbers of two calls to see + if the call is still alive after waiting for a suitable interval. It also + returns true as long as the call hasn't yet reached the completed state. + + This allows the caller to work out if the server is still contactable and + if the call is still alive on the server while waiting for the server to + process a client operation. + + The second function causes a ping ACK to be transmitted to try to provoke + the peer into responding, which would then cause the value returned by the + first function to change. Note that this must be called in TASK_RUNNING + state. + + (#) Get remote client epoch:: + + u32 rxrpc_kernel_get_epoch(struct socket *sock, + struct rxrpc_call *call) + + This allows the epoch that's contained in packets of an incoming client + call to be queried. This value is returned. The function always + successful if the call is still in progress. It shouldn't be called once + the call has expired. Note that calling this on a local client call only + returns the local epoch. + + This value can be used to determine if the remote client has been + restarted as it shouldn't change otherwise. + + (#) Set the maximum lifespan on a call:: + + void rxrpc_kernel_set_max_life(struct socket *sock, + struct rxrpc_call *call, + unsigned long hard_timeout) + + This sets the maximum lifespan on a call to hard_timeout (which is in + jiffies). In the event of the timeout occurring, the call will be + aborted and -ETIME or -ETIMEDOUT will be returned. + + (#) Apply the RXRPC_MIN_SECURITY_LEVEL sockopt to a socket from within in the + kernel:: + + int rxrpc_sock_set_min_security_level(struct sock *sk, + unsigned int val); + + This specifies the minimum security level required for calls on this + socket. + + +Configurable Parameters +======================= + +The RxRPC protocol driver has a number of configurable parameters that can be +adjusted through sysctls in /proc/net/rxrpc/: + + (#) req_ack_delay + + The amount of time in milliseconds after receiving a packet with the + request-ack flag set before we honour the flag and actually send the + requested ack. + + Usually the other side won't stop sending packets until the advertised + reception window is full (to a maximum of 255 packets), so delaying the + ACK permits several packets to be ACK'd in one go. + + (#) soft_ack_delay + + The amount of time in milliseconds after receiving a new packet before we + generate a soft-ACK to tell the sender that it doesn't need to resend. + + (#) idle_ack_delay + + The amount of time in milliseconds after all the packets currently in the + received queue have been consumed before we generate a hard-ACK to tell + the sender it can free its buffers, assuming no other reason occurs that + we would send an ACK. + + (#) resend_timeout + + The amount of time in milliseconds after transmitting a packet before we + transmit it again, assuming no ACK is received from the receiver telling + us they got it. + + (#) max_call_lifetime + + The maximum amount of time in seconds that a call may be in progress + before we preemptively kill it. + + (#) dead_call_expiry + + The amount of time in seconds before we remove a dead call from the call + list. Dead calls are kept around for a little while for the purpose of + repeating ACK and ABORT packets. + + (#) connection_expiry + + The amount of time in seconds after a connection was last used before we + remove it from the connection list. While a connection is in existence, + it serves as a placeholder for negotiated security; when it is deleted, + the security must be renegotiated. + + (#) transport_expiry + + The amount of time in seconds after a transport was last used before we + remove it from the transport list. While a transport is in existence, it + serves to anchor the peer data and keeps the connection ID counter. + + (#) rxrpc_rx_window_size + + The size of the receive window in packets. This is the maximum number of + unconsumed received packets we're willing to hold in memory for any + particular call. + + (#) rxrpc_rx_mtu + + The maximum packet MTU size that we're willing to receive in bytes. This + indicates to the peer whether we're willing to accept jumbo packets. + + (#) rxrpc_rx_jumbo_max + + The maximum number of packets that we're willing to accept in a jumbo + packet. Non-terminal packets in a jumbo packet must contain a four byte + header plus exactly 1412 bytes of data. The terminal packet must contain + a four byte header plus any amount of data. In any event, a jumbo packet + may not exceed rxrpc_rx_mtu in size. diff --git a/Documentation/networking/scaling.rst b/Documentation/networking/scaling.rst new file mode 100644 index 0000000000..92c9fb46d6 --- /dev/null +++ b/Documentation/networking/scaling.rst @@ -0,0 +1,523 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================================== +Scaling in the Linux Networking Stack +===================================== + + +Introduction +============ + +This document describes a set of complementary techniques in the Linux +networking stack to increase parallelism and improve performance for +multi-processor systems. + +The following technologies are described: + +- RSS: Receive Side Scaling +- RPS: Receive Packet Steering +- RFS: Receive Flow Steering +- Accelerated Receive Flow Steering +- XPS: Transmit Packet Steering + + +RSS: Receive Side Scaling +========================= + +Contemporary NICs support multiple receive and transmit descriptor queues +(multi-queue). On reception, a NIC can send different packets to different +queues to distribute processing among CPUs. The NIC distributes packets by +applying a filter to each packet that assigns it to one of a small number +of logical flows. Packets for each flow are steered to a separate receive +queue, which in turn can be processed by separate CPUs. This mechanism is +generally known as “Receive-side Scaling” (RSS). The goal of RSS and +the other scaling techniques is to increase performance uniformly. +Multi-queue distribution can also be used for traffic prioritization, but +that is not the focus of these techniques. + +The filter used in RSS is typically a hash function over the network +and/or transport layer headers-- for example, a 4-tuple hash over +IP addresses and TCP ports of a packet. The most common hardware +implementation of RSS uses a 128-entry indirection table where each entry +stores a queue number. The receive queue for a packet is determined +by masking out the low order seven bits of the computed hash for the +packet (usually a Toeplitz hash), taking this number as a key into the +indirection table and reading the corresponding value. + +Some advanced NICs allow steering packets to queues based on +programmable filters. For example, webserver bound TCP port 80 packets +can be directed to their own receive queue. Such “n-tuple” filters can +be configured from ethtool (--config-ntuple). + + +RSS Configuration +----------------- + +The driver for a multi-queue capable NIC typically provides a kernel +module parameter for specifying the number of hardware queues to +configure. In the bnx2x driver, for instance, this parameter is called +num_queues. A typical RSS configuration would be to have one receive queue +for each CPU if the device supports enough queues, or otherwise at least +one for each memory domain, where a memory domain is a set of CPUs that +share a particular memory level (L1, L2, NUMA node, etc.). + +The indirection table of an RSS device, which resolves a queue by masked +hash, is usually programmed by the driver at initialization. The +default mapping is to distribute the queues evenly in the table, but the +indirection table can be retrieved and modified at runtime using ethtool +commands (--show-rxfh-indir and --set-rxfh-indir). Modifying the +indirection table could be done to give different queues different +relative weights. + + +RSS IRQ Configuration +~~~~~~~~~~~~~~~~~~~~~ + +Each receive queue has a separate IRQ associated with it. The NIC triggers +this to notify a CPU when new packets arrive on the given queue. The +signaling path for PCIe devices uses message signaled interrupts (MSI-X), +that can route each interrupt to a particular CPU. The active mapping +of queues to IRQs can be determined from /proc/interrupts. By default, +an IRQ may be handled on any CPU. Because a non-negligible part of packet +processing takes place in receive interrupt handling, it is advantageous +to spread receive interrupts between CPUs. To manually adjust the IRQ +affinity of each interrupt see Documentation/core-api/irq/irq-affinity.rst. Some systems +will be running irqbalance, a daemon that dynamically optimizes IRQ +assignments and as a result may override any manual settings. + + +Suggested Configuration +~~~~~~~~~~~~~~~~~~~~~~~ + +RSS should be enabled when latency is a concern or whenever receive +interrupt processing forms a bottleneck. Spreading load between CPUs +decreases queue length. For low latency networking, the optimal setting +is to allocate as many queues as there are CPUs in the system (or the +NIC maximum, if lower). The most efficient high-rate configuration +is likely the one with the smallest number of receive queues where no +receive queue overflows due to a saturated CPU, because in default +mode with interrupt coalescing enabled, the aggregate number of +interrupts (and thus work) grows with each additional queue. + +Per-cpu load can be observed using the mpstat utility, but note that on +processors with hyperthreading (HT), each hyperthread is represented as +a separate CPU. For interrupt handling, HT has shown no benefit in +initial tests, so limit the number of queues to the number of CPU cores +in the system. + + +RPS: Receive Packet Steering +============================ + +Receive Packet Steering (RPS) is logically a software implementation of +RSS. Being in software, it is necessarily called later in the datapath. +Whereas RSS selects the queue and hence CPU that will run the hardware +interrupt handler, RPS selects the CPU to perform protocol processing +above the interrupt handler. This is accomplished by placing the packet +on the desired CPU’s backlog queue and waking up the CPU for processing. +RPS has some advantages over RSS: + +1) it can be used with any NIC +2) software filters can easily be added to hash over new protocols +3) it does not increase hardware device interrupt rate (although it does + introduce inter-processor interrupts (IPIs)) + +RPS is called during bottom half of the receive interrupt handler, when +a driver sends a packet up the network stack with netif_rx() or +netif_receive_skb(). These call the get_rps_cpu() function, which +selects the queue that should process a packet. + +The first step in determining the target CPU for RPS is to calculate a +flow hash over the packet’s addresses or ports (2-tuple or 4-tuple hash +depending on the protocol). This serves as a consistent hash of the +associated flow of the packet. The hash is either provided by hardware +or will be computed in the stack. Capable hardware can pass the hash in +the receive descriptor for the packet; this would usually be the same +hash used for RSS (e.g. computed Toeplitz hash). The hash is saved in +skb->hash and can be used elsewhere in the stack as a hash of the +packet’s flow. + +Each receive hardware queue has an associated list of CPUs to which +RPS may enqueue packets for processing. For each received packet, +an index into the list is computed from the flow hash modulo the size +of the list. The indexed CPU is the target for processing the packet, +and the packet is queued to the tail of that CPU’s backlog queue. At +the end of the bottom half routine, IPIs are sent to any CPUs for which +packets have been queued to their backlog queue. The IPI wakes backlog +processing on the remote CPU, and any queued packets are then processed +up the networking stack. + + +RPS Configuration +----------------- + +RPS requires a kernel compiled with the CONFIG_RPS kconfig symbol (on +by default for SMP). Even when compiled in, RPS remains disabled until +explicitly configured. The list of CPUs to which RPS may forward traffic +can be configured for each receive queue using a sysfs file entry:: + + /sys/class/net/<dev>/queues/rx-<n>/rps_cpus + +This file implements a bitmap of CPUs. RPS is disabled when it is zero +(the default), in which case packets are processed on the interrupting +CPU. Documentation/core-api/irq/irq-affinity.rst explains how CPUs are assigned to +the bitmap. + + +Suggested Configuration +~~~~~~~~~~~~~~~~~~~~~~~ + +For a single queue device, a typical RPS configuration would be to set +the rps_cpus to the CPUs in the same memory domain of the interrupting +CPU. If NUMA locality is not an issue, this could also be all CPUs in +the system. At high interrupt rate, it might be wise to exclude the +interrupting CPU from the map since that already performs much work. + +For a multi-queue system, if RSS is configured so that a hardware +receive queue is mapped to each CPU, then RPS is probably redundant +and unnecessary. If there are fewer hardware queues than CPUs, then +RPS might be beneficial if the rps_cpus for each queue are the ones that +share the same memory domain as the interrupting CPU for that queue. + + +RPS Flow Limit +-------------- + +RPS scales kernel receive processing across CPUs without introducing +reordering. The trade-off to sending all packets from the same flow +to the same CPU is CPU load imbalance if flows vary in packet rate. +In the extreme case a single flow dominates traffic. Especially on +common server workloads with many concurrent connections, such +behavior indicates a problem such as a misconfiguration or spoofed +source Denial of Service attack. + +Flow Limit is an optional RPS feature that prioritizes small flows +during CPU contention by dropping packets from large flows slightly +ahead of those from small flows. It is active only when an RPS or RFS +destination CPU approaches saturation. Once a CPU's input packet +queue exceeds half the maximum queue length (as set by sysctl +net.core.netdev_max_backlog), the kernel starts a per-flow packet +count over the last 256 packets. If a flow exceeds a set ratio (by +default, half) of these packets when a new packet arrives, then the +new packet is dropped. Packets from other flows are still only +dropped once the input packet queue reaches netdev_max_backlog. +No packets are dropped when the input packet queue length is below +the threshold, so flow limit does not sever connections outright: +even large flows maintain connectivity. + + +Interface +~~~~~~~~~ + +Flow limit is compiled in by default (CONFIG_NET_FLOW_LIMIT), but not +turned on. It is implemented for each CPU independently (to avoid lock +and cache contention) and toggled per CPU by setting the relevant bit +in sysctl net.core.flow_limit_cpu_bitmap. It exposes the same CPU +bitmap interface as rps_cpus (see above) when called from procfs:: + + /proc/sys/net/core/flow_limit_cpu_bitmap + +Per-flow rate is calculated by hashing each packet into a hashtable +bucket and incrementing a per-bucket counter. The hash function is +the same that selects a CPU in RPS, but as the number of buckets can +be much larger than the number of CPUs, flow limit has finer-grained +identification of large flows and fewer false positives. The default +table has 4096 buckets. This value can be modified through sysctl:: + + net.core.flow_limit_table_len + +The value is only consulted when a new table is allocated. Modifying +it does not update active tables. + + +Suggested Configuration +~~~~~~~~~~~~~~~~~~~~~~~ + +Flow limit is useful on systems with many concurrent connections, +where a single connection taking up 50% of a CPU indicates a problem. +In such environments, enable the feature on all CPUs that handle +network rx interrupts (as set in /proc/irq/N/smp_affinity). + +The feature depends on the input packet queue length to exceed +the flow limit threshold (50%) + the flow history length (256). +Setting net.core.netdev_max_backlog to either 1000 or 10000 +performed well in experiments. + + +RFS: Receive Flow Steering +========================== + +While RPS steers packets solely based on hash, and thus generally +provides good load distribution, it does not take into account +application locality. This is accomplished by Receive Flow Steering +(RFS). The goal of RFS is to increase datacache hitrate by steering +kernel processing of packets to the CPU where the application thread +consuming the packet is running. RFS relies on the same RPS mechanisms +to enqueue packets onto the backlog of another CPU and to wake up that +CPU. + +In RFS, packets are not forwarded directly by the value of their hash, +but the hash is used as index into a flow lookup table. This table maps +flows to the CPUs where those flows are being processed. The flow hash +(see RPS section above) is used to calculate the index into this table. +The CPU recorded in each entry is the one which last processed the flow. +If an entry does not hold a valid CPU, then packets mapped to that entry +are steered using plain RPS. Multiple table entries may point to the +same CPU. Indeed, with many flows and few CPUs, it is very likely that +a single application thread handles flows with many different flow hashes. + +rps_sock_flow_table is a global flow table that contains the *desired* CPU +for flows: the CPU that is currently processing the flow in userspace. +Each table value is a CPU index that is updated during calls to recvmsg +and sendmsg (specifically, inet_recvmsg(), inet_sendmsg() and +tcp_splice_read()). + +When the scheduler moves a thread to a new CPU while it has outstanding +receive packets on the old CPU, packets may arrive out of order. To +avoid this, RFS uses a second flow table to track outstanding packets +for each flow: rps_dev_flow_table is a table specific to each hardware +receive queue of each device. Each table value stores a CPU index and a +counter. The CPU index represents the *current* CPU onto which packets +for this flow are enqueued for further kernel processing. Ideally, kernel +and userspace processing occur on the same CPU, and hence the CPU index +in both tables is identical. This is likely false if the scheduler has +recently migrated a userspace thread while the kernel still has packets +enqueued for kernel processing on the old CPU. + +The counter in rps_dev_flow_table values records the length of the current +CPU's backlog when a packet in this flow was last enqueued. Each backlog +queue has a head counter that is incremented on dequeue. A tail counter +is computed as head counter + queue length. In other words, the counter +in rps_dev_flow[i] records the last element in flow i that has +been enqueued onto the currently designated CPU for flow i (of course, +entry i is actually selected by hash and multiple flows may hash to the +same entry i). + +And now the trick for avoiding out of order packets: when selecting the +CPU for packet processing (from get_rps_cpu()) the rps_sock_flow table +and the rps_dev_flow table of the queue that the packet was received on +are compared. If the desired CPU for the flow (found in the +rps_sock_flow table) matches the current CPU (found in the rps_dev_flow +table), the packet is enqueued onto that CPU’s backlog. If they differ, +the current CPU is updated to match the desired CPU if one of the +following is true: + + - The current CPU's queue head counter >= the recorded tail counter + value in rps_dev_flow[i] + - The current CPU is unset (>= nr_cpu_ids) + - The current CPU is offline + +After this check, the packet is sent to the (possibly updated) current +CPU. These rules aim to ensure that a flow only moves to a new CPU when +there are no packets outstanding on the old CPU, as the outstanding +packets could arrive later than those about to be processed on the new +CPU. + + +RFS Configuration +----------------- + +RFS is only available if the kconfig symbol CONFIG_RPS is enabled (on +by default for SMP). The functionality remains disabled until explicitly +configured. The number of entries in the global flow table is set through:: + + /proc/sys/net/core/rps_sock_flow_entries + +The number of entries in the per-queue flow table are set through:: + + /sys/class/net/<dev>/queues/rx-<n>/rps_flow_cnt + + +Suggested Configuration +~~~~~~~~~~~~~~~~~~~~~~~ + +Both of these need to be set before RFS is enabled for a receive queue. +Values for both are rounded up to the nearest power of two. The +suggested flow count depends on the expected number of active connections +at any given time, which may be significantly less than the number of open +connections. We have found that a value of 32768 for rps_sock_flow_entries +works fairly well on a moderately loaded server. + +For a single queue device, the rps_flow_cnt value for the single queue +would normally be configured to the same value as rps_sock_flow_entries. +For a multi-queue device, the rps_flow_cnt for each queue might be +configured as rps_sock_flow_entries / N, where N is the number of +queues. So for instance, if rps_sock_flow_entries is set to 32768 and there +are 16 configured receive queues, rps_flow_cnt for each queue might be +configured as 2048. + + +Accelerated RFS +=============== + +Accelerated RFS is to RFS what RSS is to RPS: a hardware-accelerated load +balancing mechanism that uses soft state to steer flows based on where +the application thread consuming the packets of each flow is running. +Accelerated RFS should perform better than RFS since packets are sent +directly to a CPU local to the thread consuming the data. The target CPU +will either be the same CPU where the application runs, or at least a CPU +which is local to the application thread’s CPU in the cache hierarchy. + +To enable accelerated RFS, the networking stack calls the +ndo_rx_flow_steer driver function to communicate the desired hardware +queue for packets matching a particular flow. The network stack +automatically calls this function every time a flow entry in +rps_dev_flow_table is updated. The driver in turn uses a device specific +method to program the NIC to steer the packets. + +The hardware queue for a flow is derived from the CPU recorded in +rps_dev_flow_table. The stack consults a CPU to hardware queue map which +is maintained by the NIC driver. This is an auto-generated reverse map of +the IRQ affinity table shown by /proc/interrupts. Drivers can use +functions in the cpu_rmap (“CPU affinity reverse map”) kernel library +to populate the map. For each CPU, the corresponding queue in the map is +set to be one whose processing CPU is closest in cache locality. + + +Accelerated RFS Configuration +----------------------------- + +Accelerated RFS is only available if the kernel is compiled with +CONFIG_RFS_ACCEL and support is provided by the NIC device and driver. +It also requires that ntuple filtering is enabled via ethtool. The map +of CPU to queues is automatically deduced from the IRQ affinities +configured for each receive queue by the driver, so no additional +configuration should be necessary. + + +Suggested Configuration +~~~~~~~~~~~~~~~~~~~~~~~ + +This technique should be enabled whenever one wants to use RFS and the +NIC supports hardware acceleration. + + +XPS: Transmit Packet Steering +============================= + +Transmit Packet Steering is a mechanism for intelligently selecting +which transmit queue to use when transmitting a packet on a multi-queue +device. This can be accomplished by recording two kinds of maps, either +a mapping of CPU to hardware queue(s) or a mapping of receive queue(s) +to hardware transmit queue(s). + +1. XPS using CPUs map + +The goal of this mapping is usually to assign queues +exclusively to a subset of CPUs, where the transmit completions for +these queues are processed on a CPU within this set. This choice +provides two benefits. First, contention on the device queue lock is +significantly reduced since fewer CPUs contend for the same queue +(contention can be eliminated completely if each CPU has its own +transmit queue). Secondly, cache miss rate on transmit completion is +reduced, in particular for data cache lines that hold the sk_buff +structures. + +2. XPS using receive queues map + +This mapping is used to pick transmit queue based on the receive +queue(s) map configuration set by the administrator. A set of receive +queues can be mapped to a set of transmit queues (many:many), although +the common use case is a 1:1 mapping. This will enable sending packets +on the same queue associations for transmit and receive. This is useful for +busy polling multi-threaded workloads where there are challenges in +associating a given CPU to a given application thread. The application +threads are not pinned to CPUs and each thread handles packets +received on a single queue. The receive queue number is cached in the +socket for the connection. In this model, sending the packets on the same +transmit queue corresponding to the associated receive queue has benefits +in keeping the CPU overhead low. Transmit completion work is locked into +the same queue-association that a given application is polling on. This +avoids the overhead of triggering an interrupt on another CPU. When the +application cleans up the packets during the busy poll, transmit completion +may be processed along with it in the same thread context and so result in +reduced latency. + +XPS is configured per transmit queue by setting a bitmap of +CPUs/receive-queues that may use that queue to transmit. The reverse +mapping, from CPUs to transmit queues or from receive-queues to transmit +queues, is computed and maintained for each network device. When +transmitting the first packet in a flow, the function get_xps_queue() is +called to select a queue. This function uses the ID of the receive queue +for the socket connection for a match in the receive queue-to-transmit queue +lookup table. Alternatively, this function can also use the ID of the +running CPU as a key into the CPU-to-queue lookup table. If the +ID matches a single queue, that is used for transmission. If multiple +queues match, one is selected by using the flow hash to compute an index +into the set. When selecting the transmit queue based on receive queue(s) +map, the transmit device is not validated against the receive device as it +requires expensive lookup operation in the datapath. + +The queue chosen for transmitting a particular flow is saved in the +corresponding socket structure for the flow (e.g. a TCP connection). +This transmit queue is used for subsequent packets sent on the flow to +prevent out of order (ooo) packets. The choice also amortizes the cost +of calling get_xps_queues() over all packets in the flow. To avoid +ooo packets, the queue for a flow can subsequently only be changed if +skb->ooo_okay is set for a packet in the flow. This flag indicates that +there are no outstanding packets in the flow, so the transmit queue can +change without the risk of generating out of order packets. The +transport layer is responsible for setting ooo_okay appropriately. TCP, +for instance, sets the flag when all data for a connection has been +acknowledged. + +XPS Configuration +----------------- + +XPS is only available if the kconfig symbol CONFIG_XPS is enabled (on by +default for SMP). If compiled in, it is driver dependent whether, and +how, XPS is configured at device init. The mapping of CPUs/receive-queues +to transmit queue can be inspected and configured using sysfs: + +For selection based on CPUs map:: + + /sys/class/net/<dev>/queues/tx-<n>/xps_cpus + +For selection based on receive-queues map:: + + /sys/class/net/<dev>/queues/tx-<n>/xps_rxqs + + +Suggested Configuration +~~~~~~~~~~~~~~~~~~~~~~~ + +For a network device with a single transmission queue, XPS configuration +has no effect, since there is no choice in this case. In a multi-queue +system, XPS is preferably configured so that each CPU maps onto one queue. +If there are as many queues as there are CPUs in the system, then each +queue can also map onto one CPU, resulting in exclusive pairings that +experience no contention. If there are fewer queues than CPUs, then the +best CPUs to share a given queue are probably those that share the cache +with the CPU that processes transmit completions for that queue +(transmit interrupts). + +For transmit queue selection based on receive queue(s), XPS has to be +explicitly configured mapping receive-queue(s) to transmit queue(s). If the +user configuration for receive-queue map does not apply, then the transmit +queue is selected based on the CPUs map. + + +Per TX Queue rate limitation +============================ + +These are rate-limitation mechanisms implemented by HW, where currently +a max-rate attribute is supported, by setting a Mbps value to:: + + /sys/class/net/<dev>/queues/tx-<n>/tx_maxrate + +A value of zero means disabled, and this is the default. + + +Further Information +=================== +RPS and RFS were introduced in kernel 2.6.35. XPS was incorporated into +2.6.38. Original patches were submitted by Tom Herbert +(therbert@google.com) + +Accelerated RFS was introduced in 2.6.35. Original patches were +submitted by Ben Hutchings (bwh@kernel.org) + +Authors: + +- Tom Herbert (therbert@google.com) +- Willem de Bruijn (willemb@google.com) diff --git a/Documentation/networking/sctp.rst b/Documentation/networking/sctp.rst new file mode 100644 index 0000000000..9f4d9c8a92 --- /dev/null +++ b/Documentation/networking/sctp.rst @@ -0,0 +1,42 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================= +Linux Kernel SCTP +================= + +This is the current BETA release of the Linux Kernel SCTP reference +implementation. + +SCTP (Stream Control Transmission Protocol) is a IP based, message oriented, +reliable transport protocol, with congestion control, support for +transparent multi-homing, and multiple ordered streams of messages. +RFC2960 defines the core protocol. The IETF SIGTRAN working group originally +developed the SCTP protocol and later handed the protocol over to the +Transport Area (TSVWG) working group for the continued evolvement of SCTP as a +general purpose transport. + +See the IETF website (http://www.ietf.org) for further documents on SCTP. +See http://www.ietf.org/rfc/rfc2960.txt + +The initial project goal is to create an Linux kernel reference implementation +of SCTP that is RFC 2960 compliant and provides an programming interface +referred to as the UDP-style API of the Sockets Extensions for SCTP, as +proposed in IETF Internet-Drafts. + +Caveats +======= + +- lksctp can be built as statically or as a module. However, be aware that + module removal of lksctp is not yet a safe activity. + +- There is tentative support for IPv6, but most work has gone towards + implementation and testing lksctp on IPv4. + + +For more information, please visit the lksctp project website: + + http://www.sf.net/projects/lksctp + +Or contact the lksctp developers through the mailing list: + + <linux-sctp@vger.kernel.org> diff --git a/Documentation/networking/secid.rst b/Documentation/networking/secid.rst new file mode 100644 index 0000000000..b45141a980 --- /dev/null +++ b/Documentation/networking/secid.rst @@ -0,0 +1,20 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================= +LSM/SeLinux secid +================= + +flowi structure: + +The secid member in the flow structure is used in LSMs (e.g. SELinux) to indicate +the label of the flow. This label of the flow is currently used in selecting +matching labeled xfrm(s). + +If this is an outbound flow, the label is derived from the socket, if any, or +the incoming packet this flow is being generated as a response to (e.g. tcp +resets, timewait ack, etc.). It is also conceivable that the label could be +derived from other sources such as process context, device, etc., in special +cases, as may be appropriate. + +If this is an inbound flow, the label is derived from the IPSec security +associations, if any, used by the packet. diff --git a/Documentation/networking/seg6-sysctl.rst b/Documentation/networking/seg6-sysctl.rst new file mode 100644 index 0000000000..07c20e470b --- /dev/null +++ b/Documentation/networking/seg6-sysctl.rst @@ -0,0 +1,39 @@ +.. SPDX-License-Identifier: GPL-2.0 + +==================== +Seg6 Sysfs variables +==================== + + +/proc/sys/net/conf/<iface>/seg6_* variables: +============================================ + +seg6_enabled - BOOL + Accept or drop SR-enabled IPv6 packets on this interface. + + Relevant packets are those with SRH present and DA = local. + + * 0 - disabled (default) + * not 0 - enabled + +seg6_require_hmac - INTEGER + Define HMAC policy for ingress SR-enabled packets on this interface. + + * -1 - Ignore HMAC field + * 0 - Accept SR packets without HMAC, validate SR packets with HMAC + * 1 - Drop SR packets without HMAC, validate SR packets with HMAC + + Default is 0. + +seg6_flowlabel - INTEGER + Controls the behaviour of computing the flowlabel of outer + IPv6 header in case of SR T.encaps + + == ======================================================= + -1 set flowlabel to zero. + 0 copy flowlabel from Inner packet in case of Inner IPv6 + (Set flowlabel to 0 in case IPv4/L2) + 1 Compute the flowlabel using seg6_make_flowlabel() + == ======================================================= + + Default is 0. diff --git a/Documentation/networking/segmentation-offloads.rst b/Documentation/networking/segmentation-offloads.rst new file mode 100644 index 0000000000..085e8fab03 --- /dev/null +++ b/Documentation/networking/segmentation-offloads.rst @@ -0,0 +1,184 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================== +Segmentation Offloads +===================== + + +Introduction +============ + +This document describes a set of techniques in the Linux networking stack +to take advantage of segmentation offload capabilities of various NICs. + +The following technologies are described: + * TCP Segmentation Offload - TSO + * UDP Fragmentation Offload - UFO + * IPIP, SIT, GRE, and UDP Tunnel Offloads + * Generic Segmentation Offload - GSO + * Generic Receive Offload - GRO + * Partial Generic Segmentation Offload - GSO_PARTIAL + * SCTP acceleration with GSO - GSO_BY_FRAGS + + +TCP Segmentation Offload +======================== + +TCP segmentation allows a device to segment a single frame into multiple +frames with a data payload size specified in skb_shinfo()->gso_size. +When TCP segmentation requested the bit for either SKB_GSO_TCPV4 or +SKB_GSO_TCPV6 should be set in skb_shinfo()->gso_type and +skb_shinfo()->gso_size should be set to a non-zero value. + +TCP segmentation is dependent on support for the use of partial checksum +offload. For this reason TSO is normally disabled if the Tx checksum +offload for a given device is disabled. + +In order to support TCP segmentation offload it is necessary to populate +the network and transport header offsets of the skbuff so that the device +drivers will be able determine the offsets of the IP or IPv6 header and the +TCP header. In addition as CHECKSUM_PARTIAL is required csum_start should +also point to the TCP header of the packet. + +For IPv4 segmentation we support one of two types in terms of the IP ID. +The default behavior is to increment the IP ID with every segment. If the +GSO type SKB_GSO_TCP_FIXEDID is specified then we will not increment the IP +ID and all segments will use the same IP ID. If a device has +NETIF_F_TSO_MANGLEID set then the IP ID can be ignored when performing TSO +and we will either increment the IP ID for all frames, or leave it at a +static value based on driver preference. + + +UDP Fragmentation Offload +========================= + +UDP fragmentation offload allows a device to fragment an oversized UDP +datagram into multiple IPv4 fragments. Many of the requirements for UDP +fragmentation offload are the same as TSO. However the IPv4 ID for +fragments should not increment as a single IPv4 datagram is fragmented. + +UFO is deprecated: modern kernels will no longer generate UFO skbs, but can +still receive them from tuntap and similar devices. Offload of UDP-based +tunnel protocols is still supported. + + +IPIP, SIT, GRE, UDP Tunnel, and Remote Checksum Offloads +======================================================== + +In addition to the offloads described above it is possible for a frame to +contain additional headers such as an outer tunnel. In order to account +for such instances an additional set of segmentation offload types were +introduced including SKB_GSO_IPXIP4, SKB_GSO_IPXIP6, SKB_GSO_GRE, and +SKB_GSO_UDP_TUNNEL. These extra segmentation types are used to identify +cases where there are more than just 1 set of headers. For example in the +case of IPIP and SIT we should have the network and transport headers moved +from the standard list of headers to "inner" header offsets. + +Currently only two levels of headers are supported. The convention is to +refer to the tunnel headers as the outer headers, while the encapsulated +data is normally referred to as the inner headers. Below is the list of +calls to access the given headers: + +IPIP/SIT Tunnel:: + + Outer Inner + MAC skb_mac_header + Network skb_network_header skb_inner_network_header + Transport skb_transport_header + +UDP/GRE Tunnel:: + + Outer Inner + MAC skb_mac_header skb_inner_mac_header + Network skb_network_header skb_inner_network_header + Transport skb_transport_header skb_inner_transport_header + +In addition to the above tunnel types there are also SKB_GSO_GRE_CSUM and +SKB_GSO_UDP_TUNNEL_CSUM. These two additional tunnel types reflect the +fact that the outer header also requests to have a non-zero checksum +included in the outer header. + +Finally there is SKB_GSO_TUNNEL_REMCSUM which indicates that a given tunnel +header has requested a remote checksum offload. In this case the inner +headers will be left with a partial checksum and only the outer header +checksum will be computed. + + +Generic Segmentation Offload +============================ + +Generic segmentation offload is a pure software offload that is meant to +deal with cases where device drivers cannot perform the offloads described +above. What occurs in GSO is that a given skbuff will have its data broken +out over multiple skbuffs that have been resized to match the MSS provided +via skb_shinfo()->gso_size. + +Before enabling any hardware segmentation offload a corresponding software +offload is required in GSO. Otherwise it becomes possible for a frame to +be re-routed between devices and end up being unable to be transmitted. + + +Generic Receive Offload +======================= + +Generic receive offload is the complement to GSO. Ideally any frame +assembled by GRO should be segmented to create an identical sequence of +frames using GSO, and any sequence of frames segmented by GSO should be +able to be reassembled back to the original by GRO. The only exception to +this is IPv4 ID in the case that the DF bit is set for a given IP header. +If the value of the IPv4 ID is not sequentially incrementing it will be +altered so that it is when a frame assembled via GRO is segmented via GSO. + + +Partial Generic Segmentation Offload +==================================== + +Partial generic segmentation offload is a hybrid between TSO and GSO. What +it effectively does is take advantage of certain traits of TCP and tunnels +so that instead of having to rewrite the packet headers for each segment +only the inner-most transport header and possibly the outer-most network +header need to be updated. This allows devices that do not support tunnel +offloads or tunnel offloads with checksum to still make use of segmentation. + +With the partial offload what occurs is that all headers excluding the +inner transport header are updated such that they will contain the correct +values for if the header was simply duplicated. The one exception to this +is the outer IPv4 ID field. It is up to the device drivers to guarantee +that the IPv4 ID field is incremented in the case that a given header does +not have the DF bit set. + + +SCTP acceleration with GSO +=========================== + +SCTP - despite the lack of hardware support - can still take advantage of +GSO to pass one large packet through the network stack, rather than +multiple small packets. + +This requires a different approach to other offloads, as SCTP packets +cannot be just segmented to (P)MTU. Rather, the chunks must be contained in +IP segments, padding respected. So unlike regular GSO, SCTP can't just +generate a big skb, set gso_size to the fragmentation point and deliver it +to IP layer. + +Instead, the SCTP protocol layer builds an skb with the segments correctly +padded and stored as chained skbs, and skb_segment() splits based on those. +To signal this, gso_size is set to the special value GSO_BY_FRAGS. + +Therefore, any code in the core networking stack must be aware of the +possibility that gso_size will be GSO_BY_FRAGS and handle that case +appropriately. + +There are some helpers to make this easier: + +- skb_is_gso(skb) && skb_is_gso_sctp(skb) is the best way to see if + an skb is an SCTP GSO skb. + +- For size checks, the skb_gso_validate_*_len family of helpers correctly + considers GSO_BY_FRAGS. + +- For manipulating packets, skb_increase_gso_size and skb_decrease_gso_size + will check for GSO_BY_FRAGS and WARN if asked to manipulate these skbs. + +This also affects drivers with the NETIF_F_FRAGLIST & NETIF_F_GSO_SCTP bits +set. Note also that NETIF_F_GSO_SCTP is included in NETIF_F_GSO_SOFTWARE. diff --git a/Documentation/networking/sfp-phylink.rst b/Documentation/networking/sfp-phylink.rst new file mode 100644 index 0000000000..55b65f607a --- /dev/null +++ b/Documentation/networking/sfp-phylink.rst @@ -0,0 +1,284 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======= +phylink +======= + +Overview +======== + +phylink is a mechanism to support hot-pluggable networking modules +directly connected to a MAC without needing to re-initialise the +adapter on hot-plug events. + +phylink supports conventional phylib-based setups, fixed link setups +and SFP (Small Formfactor Pluggable) modules at present. + +Modes of operation +================== + +phylink has several modes of operation, which depend on the firmware +settings. + +1. PHY mode + + In PHY mode, we use phylib to read the current link settings from + the PHY, and pass them to the MAC driver. We expect the MAC driver + to configure exactly the modes that are specified without any + negotiation being enabled on the link. + +2. Fixed mode + + Fixed mode is the same as PHY mode as far as the MAC driver is + concerned. + +3. In-band mode + + In-band mode is used with 802.3z, SGMII and similar interface modes, + and we are expecting to use and honor the in-band negotiation or + control word sent across the serdes channel. + +By example, what this means is that: + +.. code-block:: none + + ð { + phy = <&phy>; + phy-mode = "sgmii"; + }; + +does not use in-band SGMII signalling. The PHY is expected to follow +exactly the settings given to it in its :c:func:`mac_config` function. +The link should be forced up or down appropriately in the +:c:func:`mac_link_up` and :c:func:`mac_link_down` functions. + +.. code-block:: none + + ð { + managed = "in-band-status"; + phy = <&phy>; + phy-mode = "sgmii"; + }; + +uses in-band mode, where results from the PHY's negotiation are passed +to the MAC through the SGMII control word, and the MAC is expected to +acknowledge the control word. The :c:func:`mac_link_up` and +:c:func:`mac_link_down` functions must not force the MAC side link +up and down. + +Rough guide to converting a network driver to sfp/phylink +========================================================= + +This guide briefly describes how to convert a network driver from +phylib to the sfp/phylink support. Please send patches to improve +this documentation. + +1. Optionally split the network driver's phylib update function into + two parts dealing with link-down and link-up. This can be done as + a separate preparation commit. + + An older example of this preparation can be found in git commit + fc548b991fb0, although this was splitting into three parts; the + link-up part now includes configuring the MAC for the link settings. + Please see :c:func:`mac_link_up` for more information on this. + +2. Replace:: + + select FIXED_PHY + select PHYLIB + + with:: + + select PHYLINK + + in the driver's Kconfig stanza. + +3. Add:: + + #include <linux/phylink.h> + + to the driver's list of header files. + +4. Add:: + + struct phylink *phylink; + struct phylink_config phylink_config; + + to the driver's private data structure. We shall refer to the + driver's private data pointer as ``priv`` below, and the driver's + private data structure as ``struct foo_priv``. + +5. Replace the following functions: + + .. flat-table:: + :header-rows: 1 + :widths: 1 1 + :stub-columns: 0 + + * - Original function + - Replacement function + * - phy_start(phydev) + - phylink_start(priv->phylink) + * - phy_stop(phydev) + - phylink_stop(priv->phylink) + * - phy_mii_ioctl(phydev, ifr, cmd) + - phylink_mii_ioctl(priv->phylink, ifr, cmd) + * - phy_ethtool_get_wol(phydev, wol) + - phylink_ethtool_get_wol(priv->phylink, wol) + * - phy_ethtool_set_wol(phydev, wol) + - phylink_ethtool_set_wol(priv->phylink, wol) + * - phy_disconnect(phydev) + - phylink_disconnect_phy(priv->phylink) + + Please note that some of these functions must be called under the + rtnl lock, and will warn if not. This will normally be the case, + except if these are called from the driver suspend/resume paths. + +6. Add/replace ksettings get/set methods with: + + .. code-block:: c + + static int foo_ethtool_set_link_ksettings(struct net_device *dev, + const struct ethtool_link_ksettings *cmd) + { + struct foo_priv *priv = netdev_priv(dev); + + return phylink_ethtool_ksettings_set(priv->phylink, cmd); + } + + static int foo_ethtool_get_link_ksettings(struct net_device *dev, + struct ethtool_link_ksettings *cmd) + { + struct foo_priv *priv = netdev_priv(dev); + + return phylink_ethtool_ksettings_get(priv->phylink, cmd); + } + +7. Replace the call to:: + + phy_dev = of_phy_connect(dev, node, link_func, flags, phy_interface); + + and associated code with a call to:: + + err = phylink_of_phy_connect(priv->phylink, node, flags); + + For the most part, ``flags`` can be zero; these flags are passed to + the phy_attach_direct() inside this function call if a PHY is specified + in the DT node ``node``. + + ``node`` should be the DT node which contains the network phy property, + fixed link properties, and will also contain the sfp property. + + The setup of fixed links should also be removed; these are handled + internally by phylink. + + of_phy_connect() was also passed a function pointer for link updates. + This function is replaced by a different form of MAC updates + described below in (8). + + Manipulation of the PHY's supported/advertised happens within phylink + based on the validate callback, see below in (8). + + Note that the driver no longer needs to store the ``phy_interface``, + and also note that ``phy_interface`` becomes a dynamic property, + just like the speed, duplex etc. settings. + + Finally, note that the MAC driver has no direct access to the PHY + anymore; that is because in the phylink model, the PHY can be + dynamic. + +8. Add a :c:type:`struct phylink_mac_ops <phylink_mac_ops>` instance to + the driver, which is a table of function pointers, and implement + these functions. The old link update function for + :c:func:`of_phy_connect` becomes three methods: :c:func:`mac_link_up`, + :c:func:`mac_link_down`, and :c:func:`mac_config`. If step 1 was + performed, then the functionality will have been split there. + + It is important that if in-band negotiation is used, + :c:func:`mac_link_up` and :c:func:`mac_link_down` do not prevent the + in-band negotiation from completing, since these functions are called + when the in-band link state changes - otherwise the link will never + come up. + + The :c:func:`validate` method should mask the supplied supported mask, + and ``state->advertising`` with the supported ethtool link modes. + These are the new ethtool link modes, so bitmask operations must be + used. For an example, see ``drivers/net/ethernet/marvell/mvneta.c``. + + The :c:func:`mac_link_state` method is used to read the link state + from the MAC, and report back the settings that the MAC is currently + using. This is particularly important for in-band negotiation + methods such as 1000base-X and SGMII. + + The :c:func:`mac_link_up` method is used to inform the MAC that the + link has come up. The call includes the negotiation mode and interface + for reference only. The finalised link parameters are also supplied + (speed, duplex and flow control/pause enablement settings) which + should be used to configure the MAC when the MAC and PCS are not + tightly integrated, or when the settings are not coming from in-band + negotiation. + + The :c:func:`mac_config` method is used to update the MAC with the + requested state, and must avoid unnecessarily taking the link down + when making changes to the MAC configuration. This means the + function should modify the state and only take the link down when + absolutely necessary to change the MAC configuration. An example + of how to do this can be found in :c:func:`mvneta_mac_config` in + ``drivers/net/ethernet/marvell/mvneta.c``. + + For further information on these methods, please see the inline + documentation in :c:type:`struct phylink_mac_ops <phylink_mac_ops>`. + +9. Remove calls to of_parse_phandle() for the PHY, + of_phy_register_fixed_link() for fixed links etc. from the probe + function, and replace with: + + .. code-block:: c + + struct phylink *phylink; + priv->phylink_config.dev = &dev.dev; + priv->phylink_config.type = PHYLINK_NETDEV; + + phylink = phylink_create(&priv->phylink_config, node, phy_mode, &phylink_ops); + if (IS_ERR(phylink)) { + err = PTR_ERR(phylink); + fail probe; + } + + priv->phylink = phylink; + + and arrange to destroy the phylink in the probe failure path as + appropriate and the removal path too by calling: + + .. code-block:: c + + phylink_destroy(priv->phylink); + +10. Arrange for MAC link state interrupts to be forwarded into + phylink, via: + + .. code-block:: c + + phylink_mac_change(priv->phylink, link_is_up); + + where ``link_is_up`` is true if the link is currently up or false + otherwise. If a MAC is unable to provide these interrupts, then + it should set ``priv->phylink_config.pcs_poll = true;`` in step 9. + +11. Verify that the driver does not call:: + + netif_carrier_on() + netif_carrier_off() + + as these will interfere with phylink's tracking of the link state, + and cause phylink to omit calls via the :c:func:`mac_link_up` and + :c:func:`mac_link_down` methods. + +Network drivers should call phylink_stop() and phylink_start() via their +suspend/resume paths, which ensures that the appropriate +:c:type:`struct phylink_mac_ops <phylink_mac_ops>` methods are called +as necessary. + +For information describing the SFP cage in DT, please see the binding +documentation in the kernel source tree +``Documentation/devicetree/bindings/net/sff,sfp.yaml``. diff --git a/Documentation/networking/skbuff.rst b/Documentation/networking/skbuff.rst new file mode 100644 index 0000000000..5b74275a73 --- /dev/null +++ b/Documentation/networking/skbuff.rst @@ -0,0 +1,37 @@ +.. SPDX-License-Identifier: GPL-2.0 + +struct sk_buff +============== + +:c:type:`sk_buff` is the main networking structure representing +a packet. + +Basic sk_buff geometry +---------------------- + +.. kernel-doc:: include/linux/skbuff.h + :doc: Basic sk_buff geometry + +Shared skbs and skb clones +-------------------------- + +:c:member:`sk_buff.users` is a simple refcount allowing multiple entities +to keep a struct sk_buff alive. skbs with a ``sk_buff.users != 1`` are referred +to as shared skbs (see skb_shared()). + +skb_clone() allows for fast duplication of skbs. None of the data buffers +get copied, but caller gets a new metadata struct (struct sk_buff). +&skb_shared_info.refcount indicates the number of skbs pointing at the same +packet data (i.e. clones). + +dataref and headerless skbs +--------------------------- + +.. kernel-doc:: include/linux/skbuff.h + :doc: dataref and headerless skbs + +Checksum information +-------------------- + +.. kernel-doc:: include/linux/skbuff.h + :doc: skb checksums diff --git a/Documentation/networking/smc-sysctl.rst b/Documentation/networking/smc-sysctl.rst new file mode 100644 index 0000000000..6d8acdbe9b --- /dev/null +++ b/Documentation/networking/smc-sysctl.rst @@ -0,0 +1,61 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========== +SMC Sysctl +========== + +/proc/sys/net/smc/* Variables +============================= + +autocorking_size - INTEGER + Setting SMC auto corking size: + SMC auto corking is like TCP auto corking from the application's + perspective of view. When applications do consecutive small + write()/sendmsg() system calls, we try to coalesce these small writes + as much as possible, to lower total amount of CDC and RDMA Write been + sent. + autocorking_size limits the maximum corked bytes that can be sent to + the under device in 1 single sending. If set to 0, the SMC auto corking + is disabled. + Applications can still use TCP_CORK for optimal behavior when they + know how/when to uncork their sockets. + + Default: 64K + +smcr_buf_type - INTEGER + Controls which type of sndbufs and RMBs to use in later newly created + SMC-R link group. Only for SMC-R. + + Default: 0 (physically contiguous sndbufs and RMBs) + + Possible values: + + - 0 - Use physically contiguous buffers + - 1 - Use virtually contiguous buffers + - 2 - Mixed use of the two types. Try physically contiguous buffers first. + If not available, use virtually contiguous buffers then. + +smcr_testlink_time - INTEGER + How frequently SMC-R link sends out TEST_LINK LLC messages to confirm + viability, after the last activity of connections on it. Value 0 means + disabling TEST_LINK. + + Default: 30 seconds. + +wmem - INTEGER + Initial size of send buffer used by SMC sockets. + The default value inherits from net.ipv4.tcp_wmem[1]. + + The minimum value is 16KiB and there is no hard limit for max value, but + only allowed 512KiB for SMC-R and 1MiB for SMC-D. + + Default: 16K + +rmem - INTEGER + Initial size of receive buffer (RMB) used by SMC sockets. + The default value inherits from net.ipv4.tcp_rmem[1]. + + The minimum value is 16KiB and there is no hard limit for max value, but + only allowed 512KiB for SMC-R and 1MiB for SMC-D. + + Default: 128K diff --git a/Documentation/networking/snmp_counter.rst b/Documentation/networking/snmp_counter.rst new file mode 100644 index 0000000000..2136374744 --- /dev/null +++ b/Documentation/networking/snmp_counter.rst @@ -0,0 +1,1793 @@ +============ +SNMP counter +============ + +This document explains the meaning of SNMP counters. + +General IPv4 counters +===================== +All layer 4 packets and ICMP packets will change these counters, but +these counters won't be changed by layer 2 packets (such as STP) or +ARP packets. + +* IpInReceives + +Defined in `RFC1213 ipInReceives`_ + +.. _RFC1213 ipInReceives: https://tools.ietf.org/html/rfc1213#page-26 + +The number of packets received by the IP layer. It gets increasing at the +beginning of ip_rcv function, always be updated together with +IpExtInOctets. It will be increased even if the packet is dropped +later (e.g. due to the IP header is invalid or the checksum is wrong +and so on). It indicates the number of aggregated segments after +GRO/LRO. + +* IpInDelivers + +Defined in `RFC1213 ipInDelivers`_ + +.. _RFC1213 ipInDelivers: https://tools.ietf.org/html/rfc1213#page-28 + +The number of packets delivers to the upper layer protocols. E.g. TCP, UDP, +ICMP and so on. If no one listens on a raw socket, only kernel +supported protocols will be delivered, if someone listens on the raw +socket, all valid IP packets will be delivered. + +* IpOutRequests + +Defined in `RFC1213 ipOutRequests`_ + +.. _RFC1213 ipOutRequests: https://tools.ietf.org/html/rfc1213#page-28 + +The number of packets sent via IP layer, for both single cast and +multicast packets, and would always be updated together with +IpExtOutOctets. + +* IpExtInOctets and IpExtOutOctets + +They are Linux kernel extensions, no RFC definitions. Please note, +RFC1213 indeed defines ifInOctets and ifOutOctets, but they +are different things. The ifInOctets and ifOutOctets include the MAC +layer header size but IpExtInOctets and IpExtOutOctets don't, they +only include the IP layer header and the IP layer data. + +* IpExtInNoECTPkts, IpExtInECT1Pkts, IpExtInECT0Pkts, IpExtInCEPkts + +They indicate the number of four kinds of ECN IP packets, please refer +`Explicit Congestion Notification`_ for more details. + +.. _Explicit Congestion Notification: https://tools.ietf.org/html/rfc3168#page-6 + +These 4 counters calculate how many packets received per ECN +status. They count the real frame number regardless the LRO/GRO. So +for the same packet, you might find that IpInReceives count 1, but +IpExtInNoECTPkts counts 2 or more. + +* IpInHdrErrors + +Defined in `RFC1213 ipInHdrErrors`_. It indicates the packet is +dropped due to the IP header error. It might happen in both IP input +and IP forward paths. + +.. _RFC1213 ipInHdrErrors: https://tools.ietf.org/html/rfc1213#page-27 + +* IpInAddrErrors + +Defined in `RFC1213 ipInAddrErrors`_. It will be increased in two +scenarios: (1) The IP address is invalid. (2) The destination IP +address is not a local address and IP forwarding is not enabled + +.. _RFC1213 ipInAddrErrors: https://tools.ietf.org/html/rfc1213#page-27 + +* IpExtInNoRoutes + +This counter means the packet is dropped when the IP stack receives a +packet and can't find a route for it from the route table. It might +happen when IP forwarding is enabled and the destination IP address is +not a local address and there is no route for the destination IP +address. + +* IpInUnknownProtos + +Defined in `RFC1213 ipInUnknownProtos`_. It will be increased if the +layer 4 protocol is unsupported by kernel. If an application is using +raw socket, kernel will always deliver the packet to the raw socket +and this counter won't be increased. + +.. _RFC1213 ipInUnknownProtos: https://tools.ietf.org/html/rfc1213#page-27 + +* IpExtInTruncatedPkts + +For IPv4 packet, it means the actual data size is smaller than the +"Total Length" field in the IPv4 header. + +* IpInDiscards + +Defined in `RFC1213 ipInDiscards`_. It indicates the packet is dropped +in the IP receiving path and due to kernel internal reasons (e.g. no +enough memory). + +.. _RFC1213 ipInDiscards: https://tools.ietf.org/html/rfc1213#page-28 + +* IpOutDiscards + +Defined in `RFC1213 ipOutDiscards`_. It indicates the packet is +dropped in the IP sending path and due to kernel internal reasons. + +.. _RFC1213 ipOutDiscards: https://tools.ietf.org/html/rfc1213#page-28 + +* IpOutNoRoutes + +Defined in `RFC1213 ipOutNoRoutes`_. It indicates the packet is +dropped in the IP sending path and no route is found for it. + +.. _RFC1213 ipOutNoRoutes: https://tools.ietf.org/html/rfc1213#page-29 + +ICMP counters +============= +* IcmpInMsgs and IcmpOutMsgs + +Defined by `RFC1213 icmpInMsgs`_ and `RFC1213 icmpOutMsgs`_ + +.. _RFC1213 icmpInMsgs: https://tools.ietf.org/html/rfc1213#page-41 +.. _RFC1213 icmpOutMsgs: https://tools.ietf.org/html/rfc1213#page-43 + +As mentioned in the RFC1213, these two counters include errors, they +would be increased even if the ICMP packet has an invalid type. The +ICMP output path will check the header of a raw socket, so the +IcmpOutMsgs would still be updated if the IP header is constructed by +a userspace program. + +* ICMP named types + +| These counters include most of common ICMP types, they are: +| IcmpInDestUnreachs: `RFC1213 icmpInDestUnreachs`_ +| IcmpInTimeExcds: `RFC1213 icmpInTimeExcds`_ +| IcmpInParmProbs: `RFC1213 icmpInParmProbs`_ +| IcmpInSrcQuenchs: `RFC1213 icmpInSrcQuenchs`_ +| IcmpInRedirects: `RFC1213 icmpInRedirects`_ +| IcmpInEchos: `RFC1213 icmpInEchos`_ +| IcmpInEchoReps: `RFC1213 icmpInEchoReps`_ +| IcmpInTimestamps: `RFC1213 icmpInTimestamps`_ +| IcmpInTimestampReps: `RFC1213 icmpInTimestampReps`_ +| IcmpInAddrMasks: `RFC1213 icmpInAddrMasks`_ +| IcmpInAddrMaskReps: `RFC1213 icmpInAddrMaskReps`_ +| IcmpOutDestUnreachs: `RFC1213 icmpOutDestUnreachs`_ +| IcmpOutTimeExcds: `RFC1213 icmpOutTimeExcds`_ +| IcmpOutParmProbs: `RFC1213 icmpOutParmProbs`_ +| IcmpOutSrcQuenchs: `RFC1213 icmpOutSrcQuenchs`_ +| IcmpOutRedirects: `RFC1213 icmpOutRedirects`_ +| IcmpOutEchos: `RFC1213 icmpOutEchos`_ +| IcmpOutEchoReps: `RFC1213 icmpOutEchoReps`_ +| IcmpOutTimestamps: `RFC1213 icmpOutTimestamps`_ +| IcmpOutTimestampReps: `RFC1213 icmpOutTimestampReps`_ +| IcmpOutAddrMasks: `RFC1213 icmpOutAddrMasks`_ +| IcmpOutAddrMaskReps: `RFC1213 icmpOutAddrMaskReps`_ + +.. _RFC1213 icmpInDestUnreachs: https://tools.ietf.org/html/rfc1213#page-41 +.. _RFC1213 icmpInTimeExcds: https://tools.ietf.org/html/rfc1213#page-41 +.. _RFC1213 icmpInParmProbs: https://tools.ietf.org/html/rfc1213#page-42 +.. _RFC1213 icmpInSrcQuenchs: https://tools.ietf.org/html/rfc1213#page-42 +.. _RFC1213 icmpInRedirects: https://tools.ietf.org/html/rfc1213#page-42 +.. _RFC1213 icmpInEchos: https://tools.ietf.org/html/rfc1213#page-42 +.. _RFC1213 icmpInEchoReps: https://tools.ietf.org/html/rfc1213#page-42 +.. _RFC1213 icmpInTimestamps: https://tools.ietf.org/html/rfc1213#page-42 +.. _RFC1213 icmpInTimestampReps: https://tools.ietf.org/html/rfc1213#page-43 +.. _RFC1213 icmpInAddrMasks: https://tools.ietf.org/html/rfc1213#page-43 +.. _RFC1213 icmpInAddrMaskReps: https://tools.ietf.org/html/rfc1213#page-43 + +.. _RFC1213 icmpOutDestUnreachs: https://tools.ietf.org/html/rfc1213#page-44 +.. _RFC1213 icmpOutTimeExcds: https://tools.ietf.org/html/rfc1213#page-44 +.. _RFC1213 icmpOutParmProbs: https://tools.ietf.org/html/rfc1213#page-44 +.. _RFC1213 icmpOutSrcQuenchs: https://tools.ietf.org/html/rfc1213#page-44 +.. _RFC1213 icmpOutRedirects: https://tools.ietf.org/html/rfc1213#page-44 +.. _RFC1213 icmpOutEchos: https://tools.ietf.org/html/rfc1213#page-45 +.. _RFC1213 icmpOutEchoReps: https://tools.ietf.org/html/rfc1213#page-45 +.. _RFC1213 icmpOutTimestamps: https://tools.ietf.org/html/rfc1213#page-45 +.. _RFC1213 icmpOutTimestampReps: https://tools.ietf.org/html/rfc1213#page-45 +.. _RFC1213 icmpOutAddrMasks: https://tools.ietf.org/html/rfc1213#page-45 +.. _RFC1213 icmpOutAddrMaskReps: https://tools.ietf.org/html/rfc1213#page-46 + +Every ICMP type has two counters: 'In' and 'Out'. E.g., for the ICMP +Echo packet, they are IcmpInEchos and IcmpOutEchos. Their meanings are +straightforward. The 'In' counter means kernel receives such a packet +and the 'Out' counter means kernel sends such a packet. + +* ICMP numeric types + +They are IcmpMsgInType[N] and IcmpMsgOutType[N], the [N] indicates the +ICMP type number. These counters track all kinds of ICMP packets. The +ICMP type number definition could be found in the `ICMP parameters`_ +document. + +.. _ICMP parameters: https://www.iana.org/assignments/icmp-parameters/icmp-parameters.xhtml + +For example, if the Linux kernel sends an ICMP Echo packet, the +IcmpMsgOutType8 would increase 1. And if kernel gets an ICMP Echo Reply +packet, IcmpMsgInType0 would increase 1. + +* IcmpInCsumErrors + +This counter indicates the checksum of the ICMP packet is +wrong. Kernel verifies the checksum after updating the IcmpInMsgs and +before updating IcmpMsgInType[N]. If a packet has bad checksum, the +IcmpInMsgs would be updated but none of IcmpMsgInType[N] would be updated. + +* IcmpInErrors and IcmpOutErrors + +Defined by `RFC1213 icmpInErrors`_ and `RFC1213 icmpOutErrors`_ + +.. _RFC1213 icmpInErrors: https://tools.ietf.org/html/rfc1213#page-41 +.. _RFC1213 icmpOutErrors: https://tools.ietf.org/html/rfc1213#page-43 + +When an error occurs in the ICMP packet handler path, these two +counters would be updated. The receiving packet path use IcmpInErrors +and the sending packet path use IcmpOutErrors. When IcmpInCsumErrors +is increased, IcmpInErrors would always be increased too. + +relationship of the ICMP counters +--------------------------------- +The sum of IcmpMsgOutType[N] is always equal to IcmpOutMsgs, as they +are updated at the same time. The sum of IcmpMsgInType[N] plus +IcmpInErrors should be equal or larger than IcmpInMsgs. When kernel +receives an ICMP packet, kernel follows below logic: + +1. increase IcmpInMsgs +2. if has any error, update IcmpInErrors and finish the process +3. update IcmpMsgOutType[N] +4. handle the packet depending on the type, if has any error, update + IcmpInErrors and finish the process + +So if all errors occur in step (2), IcmpInMsgs should be equal to the +sum of IcmpMsgOutType[N] plus IcmpInErrors. If all errors occur in +step (4), IcmpInMsgs should be equal to the sum of +IcmpMsgOutType[N]. If the errors occur in both step (2) and step (4), +IcmpInMsgs should be less than the sum of IcmpMsgOutType[N] plus +IcmpInErrors. + +General TCP counters +==================== +* TcpInSegs + +Defined in `RFC1213 tcpInSegs`_ + +.. _RFC1213 tcpInSegs: https://tools.ietf.org/html/rfc1213#page-48 + +The number of packets received by the TCP layer. As mentioned in +RFC1213, it includes the packets received in error, such as checksum +error, invalid TCP header and so on. Only one error won't be included: +if the layer 2 destination address is not the NIC's layer 2 +address. It might happen if the packet is a multicast or broadcast +packet, or the NIC is in promiscuous mode. In these situations, the +packets would be delivered to the TCP layer, but the TCP layer will discard +these packets before increasing TcpInSegs. The TcpInSegs counter +isn't aware of GRO. So if two packets are merged by GRO, the TcpInSegs +counter would only increase 1. + +* TcpOutSegs + +Defined in `RFC1213 tcpOutSegs`_ + +.. _RFC1213 tcpOutSegs: https://tools.ietf.org/html/rfc1213#page-48 + +The number of packets sent by the TCP layer. As mentioned in RFC1213, +it excludes the retransmitted packets. But it includes the SYN, ACK +and RST packets. Doesn't like TcpInSegs, the TcpOutSegs is aware of +GSO, so if a packet would be split to 2 by GSO, TcpOutSegs will +increase 2. + +* TcpActiveOpens + +Defined in `RFC1213 tcpActiveOpens`_ + +.. _RFC1213 tcpActiveOpens: https://tools.ietf.org/html/rfc1213#page-47 + +It means the TCP layer sends a SYN, and come into the SYN-SENT +state. Every time TcpActiveOpens increases 1, TcpOutSegs should always +increase 1. + +* TcpPassiveOpens + +Defined in `RFC1213 tcpPassiveOpens`_ + +.. _RFC1213 tcpPassiveOpens: https://tools.ietf.org/html/rfc1213#page-47 + +It means the TCP layer receives a SYN, replies a SYN+ACK, come into +the SYN-RCVD state. + +* TcpExtTCPRcvCoalesce + +When packets are received by the TCP layer and are not be read by the +application, the TCP layer will try to merge them. This counter +indicate how many packets are merged in such situation. If GRO is +enabled, lots of packets would be merged by GRO, these packets +wouldn't be counted to TcpExtTCPRcvCoalesce. + +* TcpExtTCPAutoCorking + +When sending packets, the TCP layer will try to merge small packets to +a bigger one. This counter increase 1 for every packet merged in such +situation. Please refer to the LWN article for more details: +https://lwn.net/Articles/576263/ + +* TcpExtTCPOrigDataSent + +This counter is explained by `kernel commit f19c29e3e391`_, I pasted the +explanation below:: + + TCPOrigDataSent: number of outgoing packets with original data (excluding + retransmission but including data-in-SYN). This counter is different from + TcpOutSegs because TcpOutSegs also tracks pure ACKs. TCPOrigDataSent is + more useful to track the TCP retransmission rate. + +* TCPSynRetrans + +This counter is explained by `kernel commit f19c29e3e391`_, I pasted the +explanation below:: + + TCPSynRetrans: number of SYN and SYN/ACK retransmits to break down + retransmissions into SYN, fast-retransmits, timeout retransmits, etc. + +* TCPFastOpenActiveFail + +This counter is explained by `kernel commit f19c29e3e391`_, I pasted the +explanation below:: + + TCPFastOpenActiveFail: Fast Open attempts (SYN/data) failed because + the remote does not accept it or the attempts timed out. + +.. _kernel commit f19c29e3e391: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f19c29e3e391a66a273e9afebaf01917245148cd + +* TcpExtListenOverflows and TcpExtListenDrops + +When kernel receives a SYN from a client, and if the TCP accept queue +is full, kernel will drop the SYN and add 1 to TcpExtListenOverflows. +At the same time kernel will also add 1 to TcpExtListenDrops. When a +TCP socket is in LISTEN state, and kernel need to drop a packet, +kernel would always add 1 to TcpExtListenDrops. So increase +TcpExtListenOverflows would let TcpExtListenDrops increasing at the +same time, but TcpExtListenDrops would also increase without +TcpExtListenOverflows increasing, e.g. a memory allocation fail would +also let TcpExtListenDrops increase. + +Note: The above explanation is based on kernel 4.10 or above version, on +an old kernel, the TCP stack has different behavior when TCP accept +queue is full. On the old kernel, TCP stack won't drop the SYN, it +would complete the 3-way handshake. As the accept queue is full, TCP +stack will keep the socket in the TCP half-open queue. As it is in the +half open queue, TCP stack will send SYN+ACK on an exponential backoff +timer, after client replies ACK, TCP stack checks whether the accept +queue is still full, if it is not full, moves the socket to the accept +queue, if it is full, keeps the socket in the half-open queue, at next +time client replies ACK, this socket will get another chance to move +to the accept queue. + + +TCP Fast Open +============= +* TcpEstabResets + +Defined in `RFC1213 tcpEstabResets`_. + +.. _RFC1213 tcpEstabResets: https://tools.ietf.org/html/rfc1213#page-48 + +* TcpAttemptFails + +Defined in `RFC1213 tcpAttemptFails`_. + +.. _RFC1213 tcpAttemptFails: https://tools.ietf.org/html/rfc1213#page-48 + +* TcpOutRsts + +Defined in `RFC1213 tcpOutRsts`_. The RFC says this counter indicates +the 'segments sent containing the RST flag', but in linux kernel, this +counter indicates the segments kernel tried to send. The sending +process might be failed due to some errors (e.g. memory alloc failed). + +.. _RFC1213 tcpOutRsts: https://tools.ietf.org/html/rfc1213#page-52 + +* TcpExtTCPSpuriousRtxHostQueues + +When the TCP stack wants to retransmit a packet, and finds that packet +is not lost in the network, but the packet is not sent yet, the TCP +stack would give up the retransmission and update this counter. It +might happen if a packet stays too long time in a qdisc or driver +queue. + +* TcpEstabResets + +The socket receives a RST packet in Establish or CloseWait state. + +* TcpExtTCPKeepAlive + +This counter indicates many keepalive packets were sent. The keepalive +won't be enabled by default. A userspace program could enable it by +setting the SO_KEEPALIVE socket option. + +* TcpExtTCPSpuriousRTOs + +The spurious retransmission timeout detected by the `F-RTO`_ +algorithm. + +.. _F-RTO: https://tools.ietf.org/html/rfc5682 + +TCP Fast Path +============= +When kernel receives a TCP packet, it has two paths to handler the +packet, one is fast path, another is slow path. The comment in kernel +code provides a good explanation of them, I pasted them below:: + + It is split into a fast path and a slow path. The fast path is + disabled when: + + - A zero window was announced from us + - zero window probing + is only handled properly on the slow path. + - Out of order segments arrived. + - Urgent data is expected. + - There is no buffer space left + - Unexpected TCP flags/window values/header lengths are received + (detected by checking the TCP header against pred_flags) + - Data is sent in both directions. The fast path only supports pure senders + or pure receivers (this means either the sequence number or the ack + value must stay constant) + - Unexpected TCP option. + +Kernel will try to use fast path unless any of the above conditions +are satisfied. If the packets are out of order, kernel will handle +them in slow path, which means the performance might be not very +good. Kernel would also come into slow path if the "Delayed ack" is +used, because when using "Delayed ack", the data is sent in both +directions. When the TCP window scale option is not used, kernel will +try to enable fast path immediately when the connection comes into the +established state, but if the TCP window scale option is used, kernel +will disable the fast path at first, and try to enable it after kernel +receives packets. + +* TcpExtTCPPureAcks and TcpExtTCPHPAcks + +If a packet set ACK flag and has no data, it is a pure ACK packet, if +kernel handles it in the fast path, TcpExtTCPHPAcks will increase 1, +if kernel handles it in the slow path, TcpExtTCPPureAcks will +increase 1. + +* TcpExtTCPHPHits + +If a TCP packet has data (which means it is not a pure ACK packet), +and this packet is handled in the fast path, TcpExtTCPHPHits will +increase 1. + + +TCP abort +========= +* TcpExtTCPAbortOnData + +It means TCP layer has data in flight, but need to close the +connection. So TCP layer sends a RST to the other side, indicate the +connection is not closed very graceful. An easy way to increase this +counter is using the SO_LINGER option. Please refer to the SO_LINGER +section of the `socket man page`_: + +.. _socket man page: http://man7.org/linux/man-pages/man7/socket.7.html + +By default, when an application closes a connection, the close function +will return immediately and kernel will try to send the in-flight data +async. If you use the SO_LINGER option, set l_onoff to 1, and l_linger +to a positive number, the close function won't return immediately, but +wait for the in-flight data are acked by the other side, the max wait +time is l_linger seconds. If set l_onoff to 1 and set l_linger to 0, +when the application closes a connection, kernel will send a RST +immediately and increase the TcpExtTCPAbortOnData counter. + +* TcpExtTCPAbortOnClose + +This counter means the application has unread data in the TCP layer when +the application wants to close the TCP connection. In such a situation, +kernel will send a RST to the other side of the TCP connection. + +* TcpExtTCPAbortOnMemory + +When an application closes a TCP connection, kernel still need to track +the connection, let it complete the TCP disconnect process. E.g. an +app calls the close method of a socket, kernel sends fin to the other +side of the connection, then the app has no relationship with the +socket any more, but kernel need to keep the socket, this socket +becomes an orphan socket, kernel waits for the reply of the other side, +and would come to the TIME_WAIT state finally. When kernel has no +enough memory to keep the orphan socket, kernel would send an RST to +the other side, and delete the socket, in such situation, kernel will +increase 1 to the TcpExtTCPAbortOnMemory. Two conditions would trigger +TcpExtTCPAbortOnMemory: + +1. the memory used by the TCP protocol is higher than the third value of +the tcp_mem. Please refer the tcp_mem section in the `TCP man page`_: + +.. _TCP man page: http://man7.org/linux/man-pages/man7/tcp.7.html + +2. the orphan socket count is higher than net.ipv4.tcp_max_orphans + + +* TcpExtTCPAbortOnTimeout + +This counter will increase when any of the TCP timers expire. In such +situation, kernel won't send RST, just give up the connection. + +* TcpExtTCPAbortOnLinger + +When a TCP connection comes into FIN_WAIT_2 state, instead of waiting +for the fin packet from the other side, kernel could send a RST and +delete the socket immediately. This is not the default behavior of +Linux kernel TCP stack. By configuring the TCP_LINGER2 socket option, +you could let kernel follow this behavior. + +* TcpExtTCPAbortFailed + +The kernel TCP layer will send RST if the `RFC2525 2.17 section`_ is +satisfied. If an internal error occurs during this process, +TcpExtTCPAbortFailed will be increased. + +.. _RFC2525 2.17 section: https://tools.ietf.org/html/rfc2525#page-50 + +TCP Hybrid Slow Start +===================== +The Hybrid Slow Start algorithm is an enhancement of the traditional +TCP congestion window Slow Start algorithm. It uses two pieces of +information to detect whether the max bandwidth of the TCP path is +approached. The two pieces of information are ACK train length and +increase in packet delay. For detail information, please refer the +`Hybrid Slow Start paper`_. Either ACK train length or packet delay +hits a specific threshold, the congestion control algorithm will come +into the Congestion Avoidance state. Until v4.20, two congestion +control algorithms are using Hybrid Slow Start, they are cubic (the +default congestion control algorithm) and cdg. Four snmp counters +relate with the Hybrid Slow Start algorithm. + +.. _Hybrid Slow Start paper: https://pdfs.semanticscholar.org/25e9/ef3f03315782c7f1cbcd31b587857adae7d1.pdf + +* TcpExtTCPHystartTrainDetect + +How many times the ACK train length threshold is detected + +* TcpExtTCPHystartTrainCwnd + +The sum of CWND detected by ACK train length. Dividing this value by +TcpExtTCPHystartTrainDetect is the average CWND which detected by the +ACK train length. + +* TcpExtTCPHystartDelayDetect + +How many times the packet delay threshold is detected. + +* TcpExtTCPHystartDelayCwnd + +The sum of CWND detected by packet delay. Dividing this value by +TcpExtTCPHystartDelayDetect is the average CWND which detected by the +packet delay. + +TCP retransmission and congestion control +========================================= +The TCP protocol has two retransmission mechanisms: SACK and fast +recovery. They are exclusive with each other. When SACK is enabled, +the kernel TCP stack would use SACK, or kernel would use fast +recovery. The SACK is a TCP option, which is defined in `RFC2018`_, +the fast recovery is defined in `RFC6582`_, which is also called +'Reno'. + +The TCP congestion control is a big and complex topic. To understand +the related snmp counter, we need to know the states of the congestion +control state machine. There are 5 states: Open, Disorder, CWR, +Recovery and Loss. For details about these states, please refer page 5 +and page 6 of this document: +https://pdfs.semanticscholar.org/0e9c/968d09ab2e53e24c4dca5b2d67c7f7140f8e.pdf + +.. _RFC2018: https://tools.ietf.org/html/rfc2018 +.. _RFC6582: https://tools.ietf.org/html/rfc6582 + +* TcpExtTCPRenoRecovery and TcpExtTCPSackRecovery + +When the congestion control comes into Recovery state, if sack is +used, TcpExtTCPSackRecovery increases 1, if sack is not used, +TcpExtTCPRenoRecovery increases 1. These two counters mean the TCP +stack begins to retransmit the lost packets. + +* TcpExtTCPSACKReneging + +A packet was acknowledged by SACK, but the receiver has dropped this +packet, so the sender needs to retransmit this packet. In this +situation, the sender adds 1 to TcpExtTCPSACKReneging. A receiver +could drop a packet which has been acknowledged by SACK, although it is +unusual, it is allowed by the TCP protocol. The sender doesn't really +know what happened on the receiver side. The sender just waits until +the RTO expires for this packet, then the sender assumes this packet +has been dropped by the receiver. + +* TcpExtTCPRenoReorder + +The reorder packet is detected by fast recovery. It would only be used +if SACK is disabled. The fast recovery algorithm detects recorder by +the duplicate ACK number. E.g., if retransmission is triggered, and +the original retransmitted packet is not lost, it is just out of +order, the receiver would acknowledge multiple times, one for the +retransmitted packet, another for the arriving of the original out of +order packet. Thus the sender would find more ACks than its +expectation, and the sender knows out of order occurs. + +* TcpExtTCPTSReorder + +The reorder packet is detected when a hole is filled. E.g., assume the +sender sends packet 1,2,3,4,5, and the receiving order is +1,2,4,5,3. When the sender receives the ACK of packet 3 (which will +fill the hole), two conditions will let TcpExtTCPTSReorder increase +1: (1) if the packet 3 is not re-retransmitted yet. (2) if the packet +3 is retransmitted but the timestamp of the packet 3's ACK is earlier +than the retransmission timestamp. + +* TcpExtTCPSACKReorder + +The reorder packet detected by SACK. The SACK has two methods to +detect reorder: (1) DSACK is received by the sender. It means the +sender sends the same packet more than one times. And the only reason +is the sender believes an out of order packet is lost so it sends the +packet again. (2) Assume packet 1,2,3,4,5 are sent by the sender, and +the sender has received SACKs for packet 2 and 5, now the sender +receives SACK for packet 4 and the sender doesn't retransmit the +packet yet, the sender would know packet 4 is out of order. The TCP +stack of kernel will increase TcpExtTCPSACKReorder for both of the +above scenarios. + +* TcpExtTCPSlowStartRetrans + +The TCP stack wants to retransmit a packet and the congestion control +state is 'Loss'. + +* TcpExtTCPFastRetrans + +The TCP stack wants to retransmit a packet and the congestion control +state is not 'Loss'. + +* TcpExtTCPLostRetransmit + +A SACK points out that a retransmission packet is lost again. + +* TcpExtTCPRetransFail + +The TCP stack tries to deliver a retransmission packet to lower layers +but the lower layers return an error. + +* TcpExtTCPSynRetrans + +The TCP stack retransmits a SYN packet. + +DSACK +===== +The DSACK is defined in `RFC2883`_. The receiver uses DSACK to report +duplicate packets to the sender. There are two kinds of +duplications: (1) a packet which has been acknowledged is +duplicate. (2) an out of order packet is duplicate. The TCP stack +counts these two kinds of duplications on both receiver side and +sender side. + +.. _RFC2883 : https://tools.ietf.org/html/rfc2883 + +* TcpExtTCPDSACKOldSent + +The TCP stack receives a duplicate packet which has been acked, so it +sends a DSACK to the sender. + +* TcpExtTCPDSACKOfoSent + +The TCP stack receives an out of order duplicate packet, so it sends a +DSACK to the sender. + +* TcpExtTCPDSACKRecv + +The TCP stack receives a DSACK, which indicates an acknowledged +duplicate packet is received. + +* TcpExtTCPDSACKOfoRecv + +The TCP stack receives a DSACK, which indicate an out of order +duplicate packet is received. + +invalid SACK and DSACK +====================== +When a SACK (or DSACK) block is invalid, a corresponding counter would +be updated. The validation method is base on the start/end sequence +number of the SACK block. For more details, please refer the comment +of the function tcp_is_sackblock_valid in the kernel source code. A +SACK option could have up to 4 blocks, they are checked +individually. E.g., if 3 blocks of a SACk is invalid, the +corresponding counter would be updated 3 times. The comment of the +`Add counters for discarded SACK blocks`_ patch has additional +explanation: + +.. _Add counters for discarded SACK blocks: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=18f02545a9a16c9a89778b91a162ad16d510bb32 + +* TcpExtTCPSACKDiscard + +This counter indicates how many SACK blocks are invalid. If the invalid +SACK block is caused by ACK recording, the TCP stack will only ignore +it and won't update this counter. + +* TcpExtTCPDSACKIgnoredOld and TcpExtTCPDSACKIgnoredNoUndo + +When a DSACK block is invalid, one of these two counters would be +updated. Which counter will be updated depends on the undo_marker flag +of the TCP socket. If the undo_marker is not set, the TCP stack isn't +likely to re-transmit any packets, and we still receive an invalid +DSACK block, the reason might be that the packet is duplicated in the +middle of the network. In such scenario, TcpExtTCPDSACKIgnoredNoUndo +will be updated. If the undo_marker is set, TcpExtTCPDSACKIgnoredOld +will be updated. As implied in its name, it might be an old packet. + +SACK shift +========== +The linux networking stack stores data in sk_buff struct (skb for +short). If a SACK block acrosses multiple skb, the TCP stack will try +to re-arrange data in these skb. E.g. if a SACK block acknowledges seq +10 to 15, skb1 has seq 10 to 13, skb2 has seq 14 to 20. The seq 14 and +15 in skb2 would be moved to skb1. This operation is 'shift'. If a +SACK block acknowledges seq 10 to 20, skb1 has seq 10 to 13, skb2 has +seq 14 to 20. All data in skb2 will be moved to skb1, and skb2 will be +discard, this operation is 'merge'. + +* TcpExtTCPSackShifted + +A skb is shifted + +* TcpExtTCPSackMerged + +A skb is merged + +* TcpExtTCPSackShiftFallback + +A skb should be shifted or merged, but the TCP stack doesn't do it for +some reasons. + +TCP out of order +================ +* TcpExtTCPOFOQueue + +The TCP layer receives an out of order packet and has enough memory +to queue it. + +* TcpExtTCPOFODrop + +The TCP layer receives an out of order packet but doesn't have enough +memory, so drops it. Such packets won't be counted into +TcpExtTCPOFOQueue. + +* TcpExtTCPOFOMerge + +The received out of order packet has an overlay with the previous +packet. the overlay part will be dropped. All of TcpExtTCPOFOMerge +packets will also be counted into TcpExtTCPOFOQueue. + +TCP PAWS +======== +PAWS (Protection Against Wrapped Sequence numbers) is an algorithm +which is used to drop old packets. It depends on the TCP +timestamps. For detail information, please refer the `timestamp wiki`_ +and the `RFC of PAWS`_. + +.. _RFC of PAWS: https://tools.ietf.org/html/rfc1323#page-17 +.. _timestamp wiki: https://en.wikipedia.org/wiki/Transmission_Control_Protocol#TCP_timestamps + +* TcpExtPAWSActive + +Packets are dropped by PAWS in Syn-Sent status. + +* TcpExtPAWSEstab + +Packets are dropped by PAWS in any status other than Syn-Sent. + +TCP ACK skip +============ +In some scenarios, kernel would avoid sending duplicate ACKs too +frequently. Please find more details in the tcp_invalid_ratelimit +section of the `sysctl document`_. When kernel decides to skip an ACK +due to tcp_invalid_ratelimit, kernel would update one of below +counters to indicate the ACK is skipped in which scenario. The ACK +would only be skipped if the received packet is either a SYN packet or +it has no data. + +.. _sysctl document: https://www.kernel.org/doc/Documentation/networking/ip-sysctl.rst + +* TcpExtTCPACKSkippedSynRecv + +The ACK is skipped in Syn-Recv status. The Syn-Recv status means the +TCP stack receives a SYN and replies SYN+ACK. Now the TCP stack is +waiting for an ACK. Generally, the TCP stack doesn't need to send ACK +in the Syn-Recv status. But in several scenarios, the TCP stack need +to send an ACK. E.g., the TCP stack receives the same SYN packet +repeately, the received packet does not pass the PAWS check, or the +received packet sequence number is out of window. In these scenarios, +the TCP stack needs to send ACK. If the ACk sending frequency is higher than +tcp_invalid_ratelimit allows, the TCP stack will skip sending ACK and +increase TcpExtTCPACKSkippedSynRecv. + + +* TcpExtTCPACKSkippedPAWS + +The ACK is skipped due to PAWS (Protect Against Wrapped Sequence +numbers) check fails. If the PAWS check fails in Syn-Recv, Fin-Wait-2 +or Time-Wait statuses, the skipped ACK would be counted to +TcpExtTCPACKSkippedSynRecv, TcpExtTCPACKSkippedFinWait2 or +TcpExtTCPACKSkippedTimeWait. In all other statuses, the skipped ACK +would be counted to TcpExtTCPACKSkippedPAWS. + +* TcpExtTCPACKSkippedSeq + +The sequence number is out of window and the timestamp passes the PAWS +check and the TCP status is not Syn-Recv, Fin-Wait-2, and Time-Wait. + +* TcpExtTCPACKSkippedFinWait2 + +The ACK is skipped in Fin-Wait-2 status, the reason would be either +PAWS check fails or the received sequence number is out of window. + +* TcpExtTCPACKSkippedTimeWait + +The ACK is skipped in Time-Wait status, the reason would be either +PAWS check failed or the received sequence number is out of window. + +* TcpExtTCPACKSkippedChallenge + +The ACK is skipped if the ACK is a challenge ACK. The RFC 5961 defines +3 kind of challenge ACK, please refer `RFC 5961 section 3.2`_, +`RFC 5961 section 4.2`_ and `RFC 5961 section 5.2`_. Besides these +three scenarios, In some TCP status, the linux TCP stack would also +send challenge ACKs if the ACK number is before the first +unacknowledged number (more strict than `RFC 5961 section 5.2`_). + +.. _RFC 5961 section 3.2: https://tools.ietf.org/html/rfc5961#page-7 +.. _RFC 5961 section 4.2: https://tools.ietf.org/html/rfc5961#page-9 +.. _RFC 5961 section 5.2: https://tools.ietf.org/html/rfc5961#page-11 + +TCP receive window +================== +* TcpExtTCPWantZeroWindowAdv + +Depending on current memory usage, the TCP stack tries to set receive +window to zero. But the receive window might still be a no-zero +value. For example, if the previous window size is 10, and the TCP +stack receives 3 bytes, the current window size would be 7 even if the +window size calculated by the memory usage is zero. + +* TcpExtTCPToZeroWindowAdv + +The TCP receive window is set to zero from a no-zero value. + +* TcpExtTCPFromZeroWindowAdv + +The TCP receive window is set to no-zero value from zero. + + +Delayed ACK +=========== +The TCP Delayed ACK is a technique which is used for reducing the +packet count in the network. For more details, please refer the +`Delayed ACK wiki`_ + +.. _Delayed ACK wiki: https://en.wikipedia.org/wiki/TCP_delayed_acknowledgment + +* TcpExtDelayedACKs + +A delayed ACK timer expires. The TCP stack will send a pure ACK packet +and exit the delayed ACK mode. + +* TcpExtDelayedACKLocked + +A delayed ACK timer expires, but the TCP stack can't send an ACK +immediately due to the socket is locked by a userspace program. The +TCP stack will send a pure ACK later (after the userspace program +unlock the socket). When the TCP stack sends the pure ACK later, the +TCP stack will also update TcpExtDelayedACKs and exit the delayed ACK +mode. + +* TcpExtDelayedACKLost + +It will be updated when the TCP stack receives a packet which has been +ACKed. A Delayed ACK loss might cause this issue, but it would also be +triggered by other reasons, such as a packet is duplicated in the +network. + +Tail Loss Probe (TLP) +===================== +TLP is an algorithm which is used to detect TCP packet loss. For more +details, please refer the `TLP paper`_. + +.. _TLP paper: https://tools.ietf.org/html/draft-dukkipati-tcpm-tcp-loss-probe-01 + +* TcpExtTCPLossProbes + +A TLP probe packet is sent. + +* TcpExtTCPLossProbeRecovery + +A packet loss is detected and recovered by TLP. + +TCP Fast Open description +========================= +TCP Fast Open is a technology which allows data transfer before the +3-way handshake complete. Please refer the `TCP Fast Open wiki`_ for a +general description. + +.. _TCP Fast Open wiki: https://en.wikipedia.org/wiki/TCP_Fast_Open + +* TcpExtTCPFastOpenActive + +When the TCP stack receives an ACK packet in the SYN-SENT status, and +the ACK packet acknowledges the data in the SYN packet, the TCP stack +understand the TFO cookie is accepted by the other side, then it +updates this counter. + +* TcpExtTCPFastOpenActiveFail + +This counter indicates that the TCP stack initiated a TCP Fast Open, +but it failed. This counter would be updated in three scenarios: (1) +the other side doesn't acknowledge the data in the SYN packet. (2) The +SYN packet which has the TFO cookie is timeout at least once. (3) +after the 3-way handshake, the retransmission timeout happens +net.ipv4.tcp_retries1 times, because some middle-boxes may black-hole +fast open after the handshake. + +* TcpExtTCPFastOpenPassive + +This counter indicates how many times the TCP stack accepts the fast +open request. + +* TcpExtTCPFastOpenPassiveFail + +This counter indicates how many times the TCP stack rejects the fast +open request. It is caused by either the TFO cookie is invalid or the +TCP stack finds an error during the socket creating process. + +* TcpExtTCPFastOpenListenOverflow + +When the pending fast open request number is larger than +fastopenq->max_qlen, the TCP stack will reject the fast open request +and update this counter. When this counter is updated, the TCP stack +won't update TcpExtTCPFastOpenPassive or +TcpExtTCPFastOpenPassiveFail. The fastopenq->max_qlen is set by the +TCP_FASTOPEN socket operation and it could not be larger than +net.core.somaxconn. For example: + +setsockopt(sfd, SOL_TCP, TCP_FASTOPEN, &qlen, sizeof(qlen)); + +* TcpExtTCPFastOpenCookieReqd + +This counter indicates how many times a client wants to request a TFO +cookie. + +SYN cookies +=========== +SYN cookies are used to mitigate SYN flood, for details, please refer +the `SYN cookies wiki`_. + +.. _SYN cookies wiki: https://en.wikipedia.org/wiki/SYN_cookies + +* TcpExtSyncookiesSent + +It indicates how many SYN cookies are sent. + +* TcpExtSyncookiesRecv + +How many reply packets of the SYN cookies the TCP stack receives. + +* TcpExtSyncookiesFailed + +The MSS decoded from the SYN cookie is invalid. When this counter is +updated, the received packet won't be treated as a SYN cookie and the +TcpExtSyncookiesRecv counter won't be updated. + +Challenge ACK +============= +For details of challenge ACK, please refer the explanation of +TcpExtTCPACKSkippedChallenge. + +* TcpExtTCPChallengeACK + +The number of challenge acks sent. + +* TcpExtTCPSYNChallenge + +The number of challenge acks sent in response to SYN packets. After +updates this counter, the TCP stack might send a challenge ACK and +update the TcpExtTCPChallengeACK counter, or it might also skip to +send the challenge and update the TcpExtTCPACKSkippedChallenge. + +prune +===== +When a socket is under memory pressure, the TCP stack will try to +reclaim memory from the receiving queue and out of order queue. One of +the reclaiming method is 'collapse', which means allocate a big skb, +copy the contiguous skbs to the single big skb, and free these +contiguous skbs. + +* TcpExtPruneCalled + +The TCP stack tries to reclaim memory for a socket. After updates this +counter, the TCP stack will try to collapse the out of order queue and +the receiving queue. If the memory is still not enough, the TCP stack +will try to discard packets from the out of order queue (and update the +TcpExtOfoPruned counter) + +* TcpExtOfoPruned + +The TCP stack tries to discard packet on the out of order queue. + +* TcpExtRcvPruned + +After 'collapse' and discard packets from the out of order queue, if +the actually used memory is still larger than the max allowed memory, +this counter will be updated. It means the 'prune' fails. + +* TcpExtTCPRcvCollapsed + +This counter indicates how many skbs are freed during 'collapse'. + +examples +======== + +ping test +--------- +Run the ping command against the public dns server 8.8.8.8:: + + nstatuser@nstat-a:~$ ping 8.8.8.8 -c 1 + PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data. + 64 bytes from 8.8.8.8: icmp_seq=1 ttl=119 time=17.8 ms + + --- 8.8.8.8 ping statistics --- + 1 packets transmitted, 1 received, 0% packet loss, time 0ms + rtt min/avg/max/mdev = 17.875/17.875/17.875/0.000 ms + +The nstayt result:: + + nstatuser@nstat-a:~$ nstat + #kernel + IpInReceives 1 0.0 + IpInDelivers 1 0.0 + IpOutRequests 1 0.0 + IcmpInMsgs 1 0.0 + IcmpInEchoReps 1 0.0 + IcmpOutMsgs 1 0.0 + IcmpOutEchos 1 0.0 + IcmpMsgInType0 1 0.0 + IcmpMsgOutType8 1 0.0 + IpExtInOctets 84 0.0 + IpExtOutOctets 84 0.0 + IpExtInNoECTPkts 1 0.0 + +The Linux server sent an ICMP Echo packet, so IpOutRequests, +IcmpOutMsgs, IcmpOutEchos and IcmpMsgOutType8 were increased 1. The +server got ICMP Echo Reply from 8.8.8.8, so IpInReceives, IcmpInMsgs, +IcmpInEchoReps and IcmpMsgInType0 were increased 1. The ICMP Echo Reply +was passed to the ICMP layer via IP layer, so IpInDelivers was +increased 1. The default ping data size is 48, so an ICMP Echo packet +and its corresponding Echo Reply packet are constructed by: + +* 14 bytes MAC header +* 20 bytes IP header +* 16 bytes ICMP header +* 48 bytes data (default value of the ping command) + +So the IpExtInOctets and IpExtOutOctets are 20+16+48=84. + +tcp 3-way handshake +------------------- +On server side, we run:: + + nstatuser@nstat-b:~$ nc -lknv 0.0.0.0 9000 + Listening on [0.0.0.0] (family 0, port 9000) + +On client side, we run:: + + nstatuser@nstat-a:~$ nc -nv 192.168.122.251 9000 + Connection to 192.168.122.251 9000 port [tcp/*] succeeded! + +The server listened on tcp 9000 port, the client connected to it, they +completed the 3-way handshake. + +On server side, we can find below nstat output:: + + nstatuser@nstat-b:~$ nstat | grep -i tcp + TcpPassiveOpens 1 0.0 + TcpInSegs 2 0.0 + TcpOutSegs 1 0.0 + TcpExtTCPPureAcks 1 0.0 + +On client side, we can find below nstat output:: + + nstatuser@nstat-a:~$ nstat | grep -i tcp + TcpActiveOpens 1 0.0 + TcpInSegs 1 0.0 + TcpOutSegs 2 0.0 + +When the server received the first SYN, it replied a SYN+ACK, and came into +SYN-RCVD state, so TcpPassiveOpens increased 1. The server received +SYN, sent SYN+ACK, received ACK, so server sent 1 packet, received 2 +packets, TcpInSegs increased 2, TcpOutSegs increased 1. The last ACK +of the 3-way handshake is a pure ACK without data, so +TcpExtTCPPureAcks increased 1. + +When the client sent SYN, the client came into the SYN-SENT state, so +TcpActiveOpens increased 1, the client sent SYN, received SYN+ACK, sent +ACK, so client sent 2 packets, received 1 packet, TcpInSegs increased +1, TcpOutSegs increased 2. + +TCP normal traffic +------------------ +Run nc on server:: + + nstatuser@nstat-b:~$ nc -lkv 0.0.0.0 9000 + Listening on [0.0.0.0] (family 0, port 9000) + +Run nc on client:: + + nstatuser@nstat-a:~$ nc -v nstat-b 9000 + Connection to nstat-b 9000 port [tcp/*] succeeded! + +Input a string in the nc client ('hello' in our example):: + + nstatuser@nstat-a:~$ nc -v nstat-b 9000 + Connection to nstat-b 9000 port [tcp/*] succeeded! + hello + +The client side nstat output:: + + nstatuser@nstat-a:~$ nstat + #kernel + IpInReceives 1 0.0 + IpInDelivers 1 0.0 + IpOutRequests 1 0.0 + TcpInSegs 1 0.0 + TcpOutSegs 1 0.0 + TcpExtTCPPureAcks 1 0.0 + TcpExtTCPOrigDataSent 1 0.0 + IpExtInOctets 52 0.0 + IpExtOutOctets 58 0.0 + IpExtInNoECTPkts 1 0.0 + +The server side nstat output:: + + nstatuser@nstat-b:~$ nstat + #kernel + IpInReceives 1 0.0 + IpInDelivers 1 0.0 + IpOutRequests 1 0.0 + TcpInSegs 1 0.0 + TcpOutSegs 1 0.0 + IpExtInOctets 58 0.0 + IpExtOutOctets 52 0.0 + IpExtInNoECTPkts 1 0.0 + +Input a string in nc client side again ('world' in our example):: + + nstatuser@nstat-a:~$ nc -v nstat-b 9000 + Connection to nstat-b 9000 port [tcp/*] succeeded! + hello + world + +Client side nstat output:: + + nstatuser@nstat-a:~$ nstat + #kernel + IpInReceives 1 0.0 + IpInDelivers 1 0.0 + IpOutRequests 1 0.0 + TcpInSegs 1 0.0 + TcpOutSegs 1 0.0 + TcpExtTCPHPAcks 1 0.0 + TcpExtTCPOrigDataSent 1 0.0 + IpExtInOctets 52 0.0 + IpExtOutOctets 58 0.0 + IpExtInNoECTPkts 1 0.0 + + +Server side nstat output:: + + nstatuser@nstat-b:~$ nstat + #kernel + IpInReceives 1 0.0 + IpInDelivers 1 0.0 + IpOutRequests 1 0.0 + TcpInSegs 1 0.0 + TcpOutSegs 1 0.0 + TcpExtTCPHPHits 1 0.0 + IpExtInOctets 58 0.0 + IpExtOutOctets 52 0.0 + IpExtInNoECTPkts 1 0.0 + +Compare the first client-side nstat and the second client-side nstat, +we could find one difference: the first one had a 'TcpExtTCPPureAcks', +but the second one had a 'TcpExtTCPHPAcks'. The first server-side +nstat and the second server-side nstat had a difference too: the +second server-side nstat had a TcpExtTCPHPHits, but the first +server-side nstat didn't have it. The network traffic patterns were +exactly the same: the client sent a packet to the server, the server +replied an ACK. But kernel handled them in different ways. When the +TCP window scale option is not used, kernel will try to enable fast +path immediately when the connection comes into the established state, +but if the TCP window scale option is used, kernel will disable the +fast path at first, and try to enable it after kernel receives +packets. We could use the 'ss' command to verify whether the window +scale option is used. e.g. run below command on either server or +client:: + + nstatuser@nstat-a:~$ ss -o state established -i '( dport = :9000 or sport = :9000 ) + Netid Recv-Q Send-Q Local Address:Port Peer Address:Port + tcp 0 0 192.168.122.250:40654 192.168.122.251:9000 + ts sack cubic wscale:7,7 rto:204 rtt:0.98/0.49 mss:1448 pmtu:1500 rcvmss:536 advmss:1448 cwnd:10 bytes_acked:1 segs_out:2 segs_in:1 send 118.2Mbps lastsnd:46572 lastrcv:46572 lastack:46572 pacing_rate 236.4Mbps rcv_space:29200 rcv_ssthresh:29200 minrtt:0.98 + +The 'wscale:7,7' means both server and client set the window scale +option to 7. Now we could explain the nstat output in our test: + +In the first nstat output of client side, the client sent a packet, server +reply an ACK, when kernel handled this ACK, the fast path was not +enabled, so the ACK was counted into 'TcpExtTCPPureAcks'. + +In the second nstat output of client side, the client sent a packet again, +and received another ACK from the server, in this time, the fast path is +enabled, and the ACK was qualified for fast path, so it was handled by +the fast path, so this ACK was counted into TcpExtTCPHPAcks. + +In the first nstat output of server side, fast path was not enabled, +so there was no 'TcpExtTCPHPHits'. + +In the second nstat output of server side, the fast path was enabled, +and the packet received from client qualified for fast path, so it +was counted into 'TcpExtTCPHPHits'. + +TcpExtTCPAbortOnClose +--------------------- +On the server side, we run below python script:: + + import socket + import time + + port = 9000 + + s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) + s.bind(('0.0.0.0', port)) + s.listen(1) + sock, addr = s.accept() + while True: + time.sleep(9999999) + +This python script listen on 9000 port, but doesn't read anything from +the connection. + +On the client side, we send the string "hello" by nc:: + + nstatuser@nstat-a:~$ echo "hello" | nc nstat-b 9000 + +Then, we come back to the server side, the server has received the "hello" +packet, and the TCP layer has acked this packet, but the application didn't +read it yet. We type Ctrl-C to terminate the server script. Then we +could find TcpExtTCPAbortOnClose increased 1 on the server side:: + + nstatuser@nstat-b:~$ nstat | grep -i abort + TcpExtTCPAbortOnClose 1 0.0 + +If we run tcpdump on the server side, we could find the server sent a +RST after we type Ctrl-C. + +TcpExtTCPAbortOnMemory and TcpExtTCPAbortOnTimeout +--------------------------------------------------- +Below is an example which let the orphan socket count be higher than +net.ipv4.tcp_max_orphans. +Change tcp_max_orphans to a smaller value on client:: + + sudo bash -c "echo 10 > /proc/sys/net/ipv4/tcp_max_orphans" + +Client code (create 64 connection to server):: + + nstatuser@nstat-a:~$ cat client_orphan.py + import socket + import time + + server = 'nstat-b' # server address + port = 9000 + + count = 64 + + connection_list = [] + + for i in range(64): + s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) + s.connect((server, port)) + connection_list.append(s) + print("connection_count: %d" % len(connection_list)) + + while True: + time.sleep(99999) + +Server code (accept 64 connection from client):: + + nstatuser@nstat-b:~$ cat server_orphan.py + import socket + import time + + port = 9000 + count = 64 + + s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) + s.bind(('0.0.0.0', port)) + s.listen(count) + connection_list = [] + while True: + sock, addr = s.accept() + connection_list.append((sock, addr)) + print("connection_count: %d" % len(connection_list)) + +Run the python scripts on server and client. + +On server:: + + python3 server_orphan.py + +On client:: + + python3 client_orphan.py + +Run iptables on server:: + + sudo iptables -A INPUT -i ens3 -p tcp --destination-port 9000 -j DROP + +Type Ctrl-C on client, stop client_orphan.py. + +Check TcpExtTCPAbortOnMemory on client:: + + nstatuser@nstat-a:~$ nstat | grep -i abort + TcpExtTCPAbortOnMemory 54 0.0 + +Check orphaned socket count on client:: + + nstatuser@nstat-a:~$ ss -s + Total: 131 (kernel 0) + TCP: 14 (estab 1, closed 0, orphaned 10, synrecv 0, timewait 0/0), ports 0 + + Transport Total IP IPv6 + * 0 - - + RAW 1 0 1 + UDP 1 1 0 + TCP 14 13 1 + INET 16 14 2 + FRAG 0 0 0 + +The explanation of the test: after run server_orphan.py and +client_orphan.py, we set up 64 connections between server and +client. Run the iptables command, the server will drop all packets from +the client, type Ctrl-C on client_orphan.py, the system of the client +would try to close these connections, and before they are closed +gracefully, these connections became orphan sockets. As the iptables +of the server blocked packets from the client, the server won't receive fin +from the client, so all connection on clients would be stuck on FIN_WAIT_1 +stage, so they will keep as orphan sockets until timeout. We have echo +10 to /proc/sys/net/ipv4/tcp_max_orphans, so the client system would +only keep 10 orphan sockets, for all other orphan sockets, the client +system sent RST for them and delete them. We have 64 connections, so +the 'ss -s' command shows the system has 10 orphan sockets, and the +value of TcpExtTCPAbortOnMemory was 54. + +An additional explanation about orphan socket count: You could find the +exactly orphan socket count by the 'ss -s' command, but when kernel +decide whither increases TcpExtTCPAbortOnMemory and sends RST, kernel +doesn't always check the exactly orphan socket count. For increasing +performance, kernel checks an approximate count firstly, if the +approximate count is more than tcp_max_orphans, kernel checks the +exact count again. So if the approximate count is less than +tcp_max_orphans, but exactly count is more than tcp_max_orphans, you +would find TcpExtTCPAbortOnMemory is not increased at all. If +tcp_max_orphans is large enough, it won't occur, but if you decrease +tcp_max_orphans to a small value like our test, you might find this +issue. So in our test, the client set up 64 connections although the +tcp_max_orphans is 10. If the client only set up 11 connections, we +can't find the change of TcpExtTCPAbortOnMemory. + +Continue the previous test, we wait for several minutes. Because of the +iptables on the server blocked the traffic, the server wouldn't receive +fin, and all the client's orphan sockets would timeout on the +FIN_WAIT_1 state finally. So we wait for a few minutes, we could find +10 timeout on the client:: + + nstatuser@nstat-a:~$ nstat | grep -i abort + TcpExtTCPAbortOnTimeout 10 0.0 + +TcpExtTCPAbortOnLinger +---------------------- +The server side code:: + + nstatuser@nstat-b:~$ cat server_linger.py + import socket + import time + + port = 9000 + + s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) + s.bind(('0.0.0.0', port)) + s.listen(1) + sock, addr = s.accept() + while True: + time.sleep(9999999) + +The client side code:: + + nstatuser@nstat-a:~$ cat client_linger.py + import socket + import struct + + server = 'nstat-b' # server address + port = 9000 + + s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) + s.setsockopt(socket.SOL_SOCKET, socket.SO_LINGER, struct.pack('ii', 1, 10)) + s.setsockopt(socket.SOL_TCP, socket.TCP_LINGER2, struct.pack('i', -1)) + s.connect((server, port)) + s.close() + +Run server_linger.py on server:: + + nstatuser@nstat-b:~$ python3 server_linger.py + +Run client_linger.py on client:: + + nstatuser@nstat-a:~$ python3 client_linger.py + +After run client_linger.py, check the output of nstat:: + + nstatuser@nstat-a:~$ nstat | grep -i abort + TcpExtTCPAbortOnLinger 1 0.0 + +TcpExtTCPRcvCoalesce +-------------------- +On the server, we run a program which listen on TCP port 9000, but +doesn't read any data:: + + import socket + import time + port = 9000 + s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) + s.bind(('0.0.0.0', port)) + s.listen(1) + sock, addr = s.accept() + while True: + time.sleep(9999999) + +Save the above code as server_coalesce.py, and run:: + + python3 server_coalesce.py + +On the client, save below code as client_coalesce.py:: + + import socket + server = 'nstat-b' + port = 9000 + s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) + s.connect((server, port)) + +Run:: + + nstatuser@nstat-a:~$ python3 -i client_coalesce.py + +We use '-i' to come into the interactive mode, then a packet:: + + >>> s.send(b'foo') + 3 + +Send a packet again:: + + >>> s.send(b'bar') + 3 + +On the server, run nstat:: + + ubuntu@nstat-b:~$ nstat + #kernel + IpInReceives 2 0.0 + IpInDelivers 2 0.0 + IpOutRequests 2 0.0 + TcpInSegs 2 0.0 + TcpOutSegs 2 0.0 + TcpExtTCPRcvCoalesce 1 0.0 + IpExtInOctets 110 0.0 + IpExtOutOctets 104 0.0 + IpExtInNoECTPkts 2 0.0 + +The client sent two packets, server didn't read any data. When +the second packet arrived at server, the first packet was still in +the receiving queue. So the TCP layer merged the two packets, and we +could find the TcpExtTCPRcvCoalesce increased 1. + +TcpExtListenOverflows and TcpExtListenDrops +------------------------------------------- +On server, run the nc command, listen on port 9000:: + + nstatuser@nstat-b:~$ nc -lkv 0.0.0.0 9000 + Listening on [0.0.0.0] (family 0, port 9000) + +On client, run 3 nc commands in different terminals:: + + nstatuser@nstat-a:~$ nc -v nstat-b 9000 + Connection to nstat-b 9000 port [tcp/*] succeeded! + +The nc command only accepts 1 connection, and the accept queue length +is 1. On current linux implementation, set queue length to n means the +actual queue length is n+1. Now we create 3 connections, 1 is accepted +by nc, 2 in accepted queue, so the accept queue is full. + +Before running the 4th nc, we clean the nstat history on the server:: + + nstatuser@nstat-b:~$ nstat -n + +Run the 4th nc on the client:: + + nstatuser@nstat-a:~$ nc -v nstat-b 9000 + +If the nc server is running on kernel 4.10 or higher version, you +won't see the "Connection to ... succeeded!" string, because kernel +will drop the SYN if the accept queue is full. If the nc client is running +on an old kernel, you would see that the connection is succeeded, +because kernel would complete the 3 way handshake and keep the socket +on half open queue. I did the test on kernel 4.15. Below is the nstat +on the server:: + + nstatuser@nstat-b:~$ nstat + #kernel + IpInReceives 4 0.0 + IpInDelivers 4 0.0 + TcpInSegs 4 0.0 + TcpExtListenOverflows 4 0.0 + TcpExtListenDrops 4 0.0 + IpExtInOctets 240 0.0 + IpExtInNoECTPkts 4 0.0 + +Both TcpExtListenOverflows and TcpExtListenDrops were 4. If the time +between the 4th nc and the nstat was longer, the value of +TcpExtListenOverflows and TcpExtListenDrops would be larger, because +the SYN of the 4th nc was dropped, the client was retrying. + +IpInAddrErrors, IpExtInNoRoutes and IpOutNoRoutes +------------------------------------------------- +server A IP address: 192.168.122.250 +server B IP address: 192.168.122.251 +Prepare on server A, add a route to server B:: + + $ sudo ip route add 8.8.8.8/32 via 192.168.122.251 + +Prepare on server B, disable send_redirects for all interfaces:: + + $ sudo sysctl -w net.ipv4.conf.all.send_redirects=0 + $ sudo sysctl -w net.ipv4.conf.ens3.send_redirects=0 + $ sudo sysctl -w net.ipv4.conf.lo.send_redirects=0 + $ sudo sysctl -w net.ipv4.conf.default.send_redirects=0 + +We want to let sever A send a packet to 8.8.8.8, and route the packet +to server B. When server B receives such packet, it might send a ICMP +Redirect message to server A, set send_redirects to 0 will disable +this behavior. + +First, generate InAddrErrors. On server B, we disable IP forwarding:: + + $ sudo sysctl -w net.ipv4.conf.all.forwarding=0 + +On server A, we send packets to 8.8.8.8:: + + $ nc -v 8.8.8.8 53 + +On server B, we check the output of nstat:: + + $ nstat + #kernel + IpInReceives 3 0.0 + IpInAddrErrors 3 0.0 + IpExtInOctets 180 0.0 + IpExtInNoECTPkts 3 0.0 + +As we have let server A route 8.8.8.8 to server B, and we disabled IP +forwarding on server B, Server A sent packets to server B, then server B +dropped packets and increased IpInAddrErrors. As the nc command would +re-send the SYN packet if it didn't receive a SYN+ACK, we could find +multiple IpInAddrErrors. + +Second, generate IpExtInNoRoutes. On server B, we enable IP +forwarding:: + + $ sudo sysctl -w net.ipv4.conf.all.forwarding=1 + +Check the route table of server B and remove the default route:: + + $ ip route show + default via 192.168.122.1 dev ens3 proto static + 192.168.122.0/24 dev ens3 proto kernel scope link src 192.168.122.251 + $ sudo ip route delete default via 192.168.122.1 dev ens3 proto static + +On server A, we contact 8.8.8.8 again:: + + $ nc -v 8.8.8.8 53 + nc: connect to 8.8.8.8 port 53 (tcp) failed: Network is unreachable + +On server B, run nstat:: + + $ nstat + #kernel + IpInReceives 1 0.0 + IpOutRequests 1 0.0 + IcmpOutMsgs 1 0.0 + IcmpOutDestUnreachs 1 0.0 + IcmpMsgOutType3 1 0.0 + IpExtInNoRoutes 1 0.0 + IpExtInOctets 60 0.0 + IpExtOutOctets 88 0.0 + IpExtInNoECTPkts 1 0.0 + +We enabled IP forwarding on server B, when server B received a packet +which destination IP address is 8.8.8.8, server B will try to forward +this packet. We have deleted the default route, there was no route for +8.8.8.8, so server B increase IpExtInNoRoutes and sent the "ICMP +Destination Unreachable" message to server A. + +Third, generate IpOutNoRoutes. Run ping command on server B:: + + $ ping -c 1 8.8.8.8 + connect: Network is unreachable + +Run nstat on server B:: + + $ nstat + #kernel + IpOutNoRoutes 1 0.0 + +We have deleted the default route on server B. Server B couldn't find +a route for the 8.8.8.8 IP address, so server B increased +IpOutNoRoutes. + +TcpExtTCPACKSkippedSynRecv +-------------------------- +In this test, we send 3 same SYN packets from client to server. The +first SYN will let server create a socket, set it to Syn-Recv status, +and reply a SYN/ACK. The second SYN will let server reply the SYN/ACK +again, and record the reply time (the duplicate ACK reply time). The +third SYN will let server check the previous duplicate ACK reply time, +and decide to skip the duplicate ACK, then increase the +TcpExtTCPACKSkippedSynRecv counter. + +Run tcpdump to capture a SYN packet:: + + nstatuser@nstat-a:~$ sudo tcpdump -c 1 -w /tmp/syn.pcap port 9000 + tcpdump: listening on ens3, link-type EN10MB (Ethernet), capture size 262144 bytes + +Open another terminal, run nc command:: + + nstatuser@nstat-a:~$ nc nstat-b 9000 + +As the nstat-b didn't listen on port 9000, it should reply a RST, and +the nc command exited immediately. It was enough for the tcpdump +command to capture a SYN packet. A linux server might use hardware +offload for the TCP checksum, so the checksum in the /tmp/syn.pcap +might be not correct. We call tcprewrite to fix it:: + + nstatuser@nstat-a:~$ tcprewrite --infile=/tmp/syn.pcap --outfile=/tmp/syn_fixcsum.pcap --fixcsum + +On nstat-b, we run nc to listen on port 9000:: + + nstatuser@nstat-b:~$ nc -lkv 9000 + Listening on [0.0.0.0] (family 0, port 9000) + +On nstat-a, we blocked the packet from port 9000, or nstat-a would send +RST to nstat-b:: + + nstatuser@nstat-a:~$ sudo iptables -A INPUT -p tcp --sport 9000 -j DROP + +Send 3 SYN repeatedly to nstat-b:: + + nstatuser@nstat-a:~$ for i in {1..3}; do sudo tcpreplay -i ens3 /tmp/syn_fixcsum.pcap; done + +Check snmp counter on nstat-b:: + + nstatuser@nstat-b:~$ nstat | grep -i skip + TcpExtTCPACKSkippedSynRecv 1 0.0 + +As we expected, TcpExtTCPACKSkippedSynRecv is 1. + +TcpExtTCPACKSkippedPAWS +----------------------- +To trigger PAWS, we could send an old SYN. + +On nstat-b, let nc listen on port 9000:: + + nstatuser@nstat-b:~$ nc -lkv 9000 + Listening on [0.0.0.0] (family 0, port 9000) + +On nstat-a, run tcpdump to capture a SYN:: + + nstatuser@nstat-a:~$ sudo tcpdump -w /tmp/paws_pre.pcap -c 1 port 9000 + tcpdump: listening on ens3, link-type EN10MB (Ethernet), capture size 262144 bytes + +On nstat-a, run nc as a client to connect nstat-b:: + + nstatuser@nstat-a:~$ nc -v nstat-b 9000 + Connection to nstat-b 9000 port [tcp/*] succeeded! + +Now the tcpdump has captured the SYN and exit. We should fix the +checksum:: + + nstatuser@nstat-a:~$ tcprewrite --infile /tmp/paws_pre.pcap --outfile /tmp/paws.pcap --fixcsum + +Send the SYN packet twice:: + + nstatuser@nstat-a:~$ for i in {1..2}; do sudo tcpreplay -i ens3 /tmp/paws.pcap; done + +On nstat-b, check the snmp counter:: + + nstatuser@nstat-b:~$ nstat | grep -i skip + TcpExtTCPACKSkippedPAWS 1 0.0 + +We sent two SYN via tcpreplay, both of them would let PAWS check +failed, the nstat-b replied an ACK for the first SYN, skipped the ACK +for the second SYN, and updated TcpExtTCPACKSkippedPAWS. + +TcpExtTCPACKSkippedSeq +---------------------- +To trigger TcpExtTCPACKSkippedSeq, we send packets which have valid +timestamp (to pass PAWS check) but the sequence number is out of +window. The linux TCP stack would avoid to skip if the packet has +data, so we need a pure ACK packet. To generate such a packet, we +could create two sockets: one on port 9000, another on port 9001. Then +we capture an ACK on port 9001, change the source/destination port +numbers to match the port 9000 socket. Then we could trigger +TcpExtTCPACKSkippedSeq via this packet. + +On nstat-b, open two terminals, run two nc commands to listen on both +port 9000 and port 9001:: + + nstatuser@nstat-b:~$ nc -lkv 9000 + Listening on [0.0.0.0] (family 0, port 9000) + + nstatuser@nstat-b:~$ nc -lkv 9001 + Listening on [0.0.0.0] (family 0, port 9001) + +On nstat-a, run two nc clients:: + + nstatuser@nstat-a:~$ nc -v nstat-b 9000 + Connection to nstat-b 9000 port [tcp/*] succeeded! + + nstatuser@nstat-a:~$ nc -v nstat-b 9001 + Connection to nstat-b 9001 port [tcp/*] succeeded! + +On nstat-a, run tcpdump to capture an ACK:: + + nstatuser@nstat-a:~$ sudo tcpdump -w /tmp/seq_pre.pcap -c 1 dst port 9001 + tcpdump: listening on ens3, link-type EN10MB (Ethernet), capture size 262144 bytes + +On nstat-b, send a packet via the port 9001 socket. E.g. we sent a +string 'foo' in our example:: + + nstatuser@nstat-b:~$ nc -lkv 9001 + Listening on [0.0.0.0] (family 0, port 9001) + Connection from nstat-a 42132 received! + foo + +On nstat-a, the tcpdump should have captured the ACK. We should check +the source port numbers of the two nc clients:: + + nstatuser@nstat-a:~$ ss -ta '( dport = :9000 || dport = :9001 )' | tee + State Recv-Q Send-Q Local Address:Port Peer Address:Port + ESTAB 0 0 192.168.122.250:50208 192.168.122.251:9000 + ESTAB 0 0 192.168.122.250:42132 192.168.122.251:9001 + +Run tcprewrite, change port 9001 to port 9000, change port 42132 to +port 50208:: + + nstatuser@nstat-a:~$ tcprewrite --infile /tmp/seq_pre.pcap --outfile /tmp/seq.pcap -r 9001:9000 -r 42132:50208 --fixcsum + +Now the /tmp/seq.pcap is the packet we need. Send it to nstat-b:: + + nstatuser@nstat-a:~$ for i in {1..2}; do sudo tcpreplay -i ens3 /tmp/seq.pcap; done + +Check TcpExtTCPACKSkippedSeq on nstat-b:: + + nstatuser@nstat-b:~$ nstat | grep -i skip + TcpExtTCPACKSkippedSeq 1 0.0 diff --git a/Documentation/networking/statistics.rst b/Documentation/networking/statistics.rst new file mode 100644 index 0000000000..551b3cc29a --- /dev/null +++ b/Documentation/networking/statistics.rst @@ -0,0 +1,221 @@ +.. SPDX-License-Identifier: GPL-2.0 + +==================== +Interface statistics +==================== + +Overview +======== + +This document is a guide to Linux network interface statistics. + +There are three main sources of interface statistics in Linux: + + - standard interface statistics based on + :c:type:`struct rtnl_link_stats64 <rtnl_link_stats64>`; + - protocol-specific statistics; and + - driver-defined statistics available via ethtool. + +Standard interface statistics +----------------------------- + +There are multiple interfaces to reach the standard statistics. +Most commonly used is the `ip` command from `iproute2`:: + + $ ip -s -s link show dev ens4u1u1 + 6: ens4u1u1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000 + link/ether 48:2a:e3:4c:b1:d1 brd ff:ff:ff:ff:ff:ff + RX: bytes packets errors dropped overrun mcast + 74327665117 69016965 0 0 0 0 + RX errors: length crc frame fifo missed + 0 0 0 0 0 + TX: bytes packets errors dropped carrier collsns + 21405556176 44608960 0 0 0 0 + TX errors: aborted fifo window heartbeat transns + 0 0 0 0 128 + altname enp58s0u1u1 + +Note that `-s` has been specified twice to see all members of +:c:type:`struct rtnl_link_stats64 <rtnl_link_stats64>`. +If `-s` is specified once the detailed errors won't be shown. + +`ip` supports JSON formatting via the `-j` option. + +Protocol-specific statistics +---------------------------- + +Protocol-specific statistics are exposed via relevant interfaces, +the same interfaces as are used to configure them. + +ethtool +~~~~~~~ + +Ethtool exposes common low-level statistics. +All the standard statistics are expected to be maintained +by the device, not the driver (as opposed to driver-defined stats +described in the next section which mix software and hardware stats). +For devices which contain unmanaged +switches (e.g. legacy SR-IOV or multi-host NICs) the events counted +may not pertain exclusively to the packets destined to +the local host interface. In other words the events may +be counted at the network port (MAC/PHY blocks) without separation +for different host side (PCIe) devices. Such ambiguity must not +be present when internal switch is managed by Linux (so called +switchdev mode for NICs). + +Standard ethtool statistics can be accessed via the interfaces used +for configuration. For example ethtool interface used +to configure pause frames can report corresponding hardware counters:: + + $ ethtool --include-statistics -a eth0 + Pause parameters for eth0: + Autonegotiate: on + RX: on + TX: on + Statistics: + tx_pause_frames: 1 + rx_pause_frames: 1 + +General Ethernet statistics not associated with any particular +functionality are exposed via ``ethtool -S $ifc`` by specifying +the ``--groups`` parameter:: + + $ ethtool -S eth0 --groups eth-phy eth-mac eth-ctrl rmon + Stats for eth0: + eth-phy-SymbolErrorDuringCarrier: 0 + eth-mac-FramesTransmittedOK: 1 + eth-mac-FrameTooLongErrors: 1 + eth-ctrl-MACControlFramesTransmitted: 1 + eth-ctrl-MACControlFramesReceived: 0 + eth-ctrl-UnsupportedOpcodesReceived: 1 + rmon-etherStatsUndersizePkts: 1 + rmon-etherStatsJabbers: 0 + rmon-rx-etherStatsPkts64Octets: 1 + rmon-rx-etherStatsPkts65to127Octets: 0 + rmon-rx-etherStatsPkts128to255Octets: 0 + rmon-tx-etherStatsPkts64Octets: 2 + rmon-tx-etherStatsPkts65to127Octets: 3 + rmon-tx-etherStatsPkts128to255Octets: 0 + +Driver-defined statistics +------------------------- + +Driver-defined ethtool statistics can be dumped using `ethtool -S $ifc`, e.g.:: + + $ ethtool -S ens4u1u1 + NIC statistics: + tx_single_collisions: 0 + tx_multi_collisions: 0 + +uAPIs +===== + +procfs +------ + +The historical `/proc/net/dev` text interface gives access to the list +of interfaces as well as their statistics. + +Note that even though this interface is using +:c:type:`struct rtnl_link_stats64 <rtnl_link_stats64>` +internally it combines some of the fields. + +sysfs +----- + +Each device directory in sysfs contains a `statistics` directory (e.g. +`/sys/class/net/lo/statistics/`) with files corresponding to +members of :c:type:`struct rtnl_link_stats64 <rtnl_link_stats64>`. + +This simple interface is convenient especially in constrained/embedded +environments without access to tools. However, it's inefficient when +reading multiple stats as it internally performs a full dump of +:c:type:`struct rtnl_link_stats64 <rtnl_link_stats64>` +and reports only the stat corresponding to the accessed file. + +Sysfs files are documented in +`Documentation/ABI/testing/sysfs-class-net-statistics`. + + +netlink +------- + +`rtnetlink` (`NETLINK_ROUTE`) is the preferred method of accessing +:c:type:`struct rtnl_link_stats64 <rtnl_link_stats64>` stats. + +Statistics are reported both in the responses to link information +requests (`RTM_GETLINK`) and statistic requests (`RTM_GETSTATS`, +when `IFLA_STATS_LINK_64` bit is set in the `.filter_mask` of the request). + +ethtool +------- + +Ethtool IOCTL interface allows drivers to report implementation +specific statistics. Historically it has also been used to report +statistics for which other APIs did not exist, like per-device-queue +statistics, or standard-based statistics (e.g. RFC 2863). + +Statistics and their string identifiers are retrieved separately. +Identifiers via `ETHTOOL_GSTRINGS` with `string_set` set to `ETH_SS_STATS`, +and values via `ETHTOOL_GSTATS`. User space should use `ETHTOOL_GDRVINFO` +to retrieve the number of statistics (`.n_stats`). + +ethtool-netlink +--------------- + +Ethtool netlink is a replacement for the older IOCTL interface. + +Protocol-related statistics can be requested in get commands by setting +the `ETHTOOL_FLAG_STATS` flag in `ETHTOOL_A_HEADER_FLAGS`. Currently +statistics are supported in the following commands: + + - `ETHTOOL_MSG_PAUSE_GET` + - `ETHTOOL_MSG_FEC_GET` + - `ETHTOOL_MSG_MM_GET` + +debugfs +------- + +Some drivers expose extra statistics via `debugfs`. + +struct rtnl_link_stats64 +======================== + +.. kernel-doc:: include/uapi/linux/if_link.h + :identifiers: rtnl_link_stats64 + +Notes for driver authors +======================== + +Drivers should report all statistics which have a matching member in +:c:type:`struct rtnl_link_stats64 <rtnl_link_stats64>` exclusively +via `.ndo_get_stats64`. Reporting such standard stats via ethtool +or debugfs will not be accepted. + +Drivers must ensure best possible compliance with +:c:type:`struct rtnl_link_stats64 <rtnl_link_stats64>`. +Please note for example that detailed error statistics must be +added into the general `rx_error` / `tx_error` counters. + +The `.ndo_get_stats64` callback can not sleep because of accesses +via `/proc/net/dev`. If driver may sleep when retrieving the statistics +from the device it should do so periodically asynchronously and only return +a recent copy from `.ndo_get_stats64`. Ethtool interrupt coalescing interface +allows setting the frequency of refreshing statistics, if needed. + +Retrieving ethtool statistics is a multi-syscall process, drivers are advised +to keep the number of statistics constant to avoid race conditions with +user space trying to read them. + +Statistics must persist across routine operations like bringing the interface +down and up. + +Kernel-internal data structures +------------------------------- + +The following structures are internal to the kernel, their members are +translated to netlink attributes when dumped. Drivers must not overwrite +the statistics they don't report with 0. + +- ethtool_pause_stats() +- ethtool_fec_stats() diff --git a/Documentation/networking/strparser.rst b/Documentation/networking/strparser.rst new file mode 100644 index 0000000000..6cab1f74ae --- /dev/null +++ b/Documentation/networking/strparser.rst @@ -0,0 +1,240 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================= +Stream Parser (strparser) +========================= + +Introduction +============ + +The stream parser (strparser) is a utility that parses messages of an +application layer protocol running over a data stream. The stream +parser works in conjunction with an upper layer in the kernel to provide +kernel support for application layer messages. For instance, Kernel +Connection Multiplexor (KCM) uses the Stream Parser to parse messages +using a BPF program. + +The strparser works in one of two modes: receive callback or general +mode. + +In receive callback mode, the strparser is called from the data_ready +callback of a TCP socket. Messages are parsed and delivered as they are +received on the socket. + +In general mode, a sequence of skbs are fed to strparser from an +outside source. Message are parsed and delivered as the sequence is +processed. This modes allows strparser to be applied to arbitrary +streams of data. + +Interface +========= + +The API includes a context structure, a set of callbacks, utility +functions, and a data_ready function for receive callback mode. The +callbacks include a parse_msg function that is called to perform +parsing (e.g. BPF parsing in case of KCM), and a rcv_msg function +that is called when a full message has been completed. + +Functions +========= + + :: + + strp_init(struct strparser *strp, struct sock *sk, + const struct strp_callbacks *cb) + + Called to initialize a stream parser. strp is a struct of type + strparser that is allocated by the upper layer. sk is the TCP + socket associated with the stream parser for use with receive + callback mode; in general mode this is set to NULL. Callbacks + are called by the stream parser (the callbacks are listed below). + + :: + + void strp_pause(struct strparser *strp) + + Temporarily pause a stream parser. Message parsing is suspended + and no new messages are delivered to the upper layer. + + :: + + void strp_unpause(struct strparser *strp) + + Unpause a paused stream parser. + + :: + + void strp_stop(struct strparser *strp); + + strp_stop is called to completely stop stream parser operations. + This is called internally when the stream parser encounters an + error, and it is called from the upper layer to stop parsing + operations. + + :: + + void strp_done(struct strparser *strp); + + strp_done is called to release any resources held by the stream + parser instance. This must be called after the stream processor + has been stopped. + + :: + + int strp_process(struct strparser *strp, struct sk_buff *orig_skb, + unsigned int orig_offset, size_t orig_len, + size_t max_msg_size, long timeo) + + strp_process is called in general mode for a stream parser to + parse an sk_buff. The number of bytes processed or a negative + error number is returned. Note that strp_process does not + consume the sk_buff. max_msg_size is maximum size the stream + parser will parse. timeo is timeout for completing a message. + + :: + + void strp_data_ready(struct strparser *strp); + + The upper layer calls strp_tcp_data_ready when data is ready on + the lower socket for strparser to process. This should be called + from a data_ready callback that is set on the socket. Note that + maximum messages size is the limit of the receive socket + buffer and message timeout is the receive timeout for the socket. + + :: + + void strp_check_rcv(struct strparser *strp); + + strp_check_rcv is called to check for new messages on the socket. + This is normally called at initialization of a stream parser + instance or after strp_unpause. + +Callbacks +========= + +There are six callbacks: + + :: + + int (*parse_msg)(struct strparser *strp, struct sk_buff *skb); + + parse_msg is called to determine the length of the next message + in the stream. The upper layer must implement this function. It + should parse the sk_buff as containing the headers for the + next application layer message in the stream. + + The skb->cb in the input skb is a struct strp_msg. Only + the offset field is relevant in parse_msg and gives the offset + where the message starts in the skb. + + The return values of this function are: + + ========= =========================================================== + >0 indicates length of successfully parsed message + 0 indicates more data must be received to parse the message + -ESTRPIPE current message should not be processed by the + kernel, return control of the socket to userspace which + can proceed to read the messages itself + other < 0 Error in parsing, give control back to userspace + assuming that synchronization is lost and the stream + is unrecoverable (application expected to close TCP socket) + ========= =========================================================== + + In the case that an error is returned (return value is less than + zero) and the parser is in receive callback mode, then it will set + the error on TCP socket and wake it up. If parse_msg returned + -ESTRPIPE and the stream parser had previously read some bytes for + the current message, then the error set on the attached socket is + ENODATA since the stream is unrecoverable in that case. + + :: + + void (*lock)(struct strparser *strp) + + The lock callback is called to lock the strp structure when + the strparser is performing an asynchronous operation (such as + processing a timeout). In receive callback mode the default + function is to lock_sock for the associated socket. In general + mode the callback must be set appropriately. + + :: + + void (*unlock)(struct strparser *strp) + + The unlock callback is called to release the lock obtained + by the lock callback. In receive callback mode the default + function is release_sock for the associated socket. In general + mode the callback must be set appropriately. + + :: + + void (*rcv_msg)(struct strparser *strp, struct sk_buff *skb); + + rcv_msg is called when a full message has been received and + is queued. The callee must consume the sk_buff; it can + call strp_pause to prevent any further messages from being + received in rcv_msg (see strp_pause above). This callback + must be set. + + The skb->cb in the input skb is a struct strp_msg. This + struct contains two fields: offset and full_len. Offset is + where the message starts in the skb, and full_len is the + the length of the message. skb->len - offset may be greater + then full_len since strparser does not trim the skb. + + :: + + int (*read_sock_done)(struct strparser *strp, int err); + + read_sock_done is called when the stream parser is done reading + the TCP socket in receive callback mode. The stream parser may + read multiple messages in a loop and this function allows cleanup + to occur when exiting the loop. If the callback is not set (NULL + in strp_init) a default function is used. + + :: + + void (*abort_parser)(struct strparser *strp, int err); + + This function is called when stream parser encounters an error + in parsing. The default function stops the stream parser and + sets the error in the socket if the parser is in receive callback + mode. The default function can be changed by setting the callback + to non-NULL in strp_init. + +Statistics +========== + +Various counters are kept for each stream parser instance. These are in +the strp_stats structure. strp_aggr_stats is a convenience structure for +accumulating statistics for multiple stream parser instances. +save_strp_stats and aggregate_strp_stats are helper functions to save +and aggregate statistics. + +Message assembly limits +======================= + +The stream parser provide mechanisms to limit the resources consumed by +message assembly. + +A timer is set when assembly starts for a new message. In receive +callback mode the message timeout is taken from rcvtime for the +associated TCP socket. In general mode, the timeout is passed as an +argument in strp_process. If the timer fires before assembly completes +the stream parser is aborted and the ETIMEDOUT error is set on the TCP +socket if in receive callback mode. + +In receive callback mode, message length is limited to the receive +buffer size of the associated TCP socket. If the length returned by +parse_msg is greater than the socket buffer size then the stream parser +is aborted with EMSGSIZE error set on the TCP socket. Note that this +makes the maximum size of receive skbuffs for a socket with a stream +parser to be 2*sk_rcvbuf of the TCP socket. + +In general mode the message length limit is passed in as an argument +to strp_process. + +Author +====== + +Tom Herbert (tom@quantonium.net) diff --git a/Documentation/networking/switchdev.rst b/Documentation/networking/switchdev.rst new file mode 100644 index 0000000000..758f1dae3f --- /dev/null +++ b/Documentation/networking/switchdev.rst @@ -0,0 +1,564 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> +.. _switchdev: + +=============================================== +Ethernet switch device driver model (switchdev) +=============================================== + +Copyright |copy| 2014 Jiri Pirko <jiri@resnulli.us> + +Copyright |copy| 2014-2015 Scott Feldman <sfeldma@gmail.com> + + +The Ethernet switch device driver model (switchdev) is an in-kernel driver +model for switch devices which offload the forwarding (data) plane from the +kernel. + +Figure 1 is a block diagram showing the components of the switchdev model for +an example setup using a data-center-class switch ASIC chip. Other setups +with SR-IOV or soft switches, such as OVS, are possible. + +:: + + + User-space tools + + user space | + +-------------------------------------------------------------------+ + kernel | Netlink + | + +--------------+-------------------------------+ + | Network stack | + | (Linux) | + | | + +----------------------------------------------+ + + sw1p2 sw1p4 sw1p6 + sw1p1 + sw1p3 + sw1p5 + eth1 + + | + | + | + + | | | | | | | + +--+----+----+----+----+----+---+ +-----+-----+ + | Switch driver | | mgmt | + | (this document) | | driver | + | | | | + +--------------+----------------+ +-----------+ + | + kernel | HW bus (eg PCI) + +-------------------------------------------------------------------+ + hardware | + +--------------+----------------+ + | Switch device (sw1) | + | +----+ +--------+ + | | v offloaded data path | mgmt port + | | | | + +--|----|----+----+----+----+---+ + | | | | | | + + + + + + + + p1 p2 p3 p4 p5 p6 + + front-panel ports + + + Fig 1. + + +Include Files +------------- + +:: + + #include <linux/netdevice.h> + #include <net/switchdev.h> + + +Configuration +------------- + +Use "depends NET_SWITCHDEV" in driver's Kconfig to ensure switchdev model +support is built for driver. + + +Switch Ports +------------ + +On switchdev driver initialization, the driver will allocate and register a +struct net_device (using register_netdev()) for each enumerated physical switch +port, called the port netdev. A port netdev is the software representation of +the physical port and provides a conduit for control traffic to/from the +controller (the kernel) and the network, as well as an anchor point for higher +level constructs such as bridges, bonds, VLANs, tunnels, and L3 routers. Using +standard netdev tools (iproute2, ethtool, etc), the port netdev can also +provide to the user access to the physical properties of the switch port such +as PHY link state and I/O statistics. + +There is (currently) no higher-level kernel object for the switch beyond the +port netdevs. All of the switchdev driver ops are netdev ops or switchdev ops. + +A switch management port is outside the scope of the switchdev driver model. +Typically, the management port is not participating in offloaded data plane and +is loaded with a different driver, such as a NIC driver, on the management port +device. + +Switch ID +^^^^^^^^^ + +The switchdev driver must implement the net_device operation +ndo_get_port_parent_id for each port netdev, returning the same physical ID for +each port of a switch. The ID must be unique between switches on the same +system. The ID does not need to be unique between switches on different +systems. + +The switch ID is used to locate ports on a switch and to know if aggregated +ports belong to the same switch. + +Port Netdev Naming +^^^^^^^^^^^^^^^^^^ + +Udev rules should be used for port netdev naming, using some unique attribute +of the port as a key, for example the port MAC address or the port PHYS name. +Hard-coding of kernel netdev names within the driver is discouraged; let the +kernel pick the default netdev name, and let udev set the final name based on a +port attribute. + +Using port PHYS name (ndo_get_phys_port_name) for the key is particularly +useful for dynamically-named ports where the device names its ports based on +external configuration. For example, if a physical 40G port is split logically +into 4 10G ports, resulting in 4 port netdevs, the device can give a unique +name for each port using port PHYS name. The udev rule would be:: + + SUBSYSTEM=="net", ACTION=="add", ATTR{phys_switch_id}=="<phys_switch_id>", \ + ATTR{phys_port_name}!="", NAME="swX$attr{phys_port_name}" + +Suggested naming convention is "swXpYsZ", where X is the switch name or ID, Y +is the port name or ID, and Z is the sub-port name or ID. For example, sw1p1s0 +would be sub-port 0 on port 1 on switch 1. + +Port Features +^^^^^^^^^^^^^ + +NETIF_F_NETNS_LOCAL + +If the switchdev driver (and device) only supports offloading of the default +network namespace (netns), the driver should set this feature flag to prevent +the port netdev from being moved out of the default netns. A netns-aware +driver/device would not set this flag and be responsible for partitioning +hardware to preserve netns containment. This means hardware cannot forward +traffic from a port in one namespace to another port in another namespace. + +Port Topology +^^^^^^^^^^^^^ + +The port netdevs representing the physical switch ports can be organized into +higher-level switching constructs. The default construct is a standalone +router port, used to offload L3 forwarding. Two or more ports can be bonded +together to form a LAG. Two or more ports (or LAGs) can be bridged to bridge +L2 networks. VLANs can be applied to sub-divide L2 networks. L2-over-L3 +tunnels can be built on ports. These constructs are built using standard Linux +tools such as the bridge driver, the bonding/team drivers, and netlink-based +tools such as iproute2. + +The switchdev driver can know a particular port's position in the topology by +monitoring NETDEV_CHANGEUPPER notifications. For example, a port moved into a +bond will see its upper master change. If that bond is moved into a bridge, +the bond's upper master will change. And so on. The driver will track such +movements to know what position a port is in in the overall topology by +registering for netdevice events and acting on NETDEV_CHANGEUPPER. + +L2 Forwarding Offload +--------------------- + +The idea is to offload the L2 data forwarding (switching) path from the kernel +to the switchdev device by mirroring bridge FDB entries down to the device. An +FDB entry is the {port, MAC, VLAN} tuple forwarding destination. + +To offloading L2 bridging, the switchdev driver/device should support: + + - Static FDB entries installed on a bridge port + - Notification of learned/forgotten src mac/vlans from device + - STP state changes on the port + - VLAN flooding of multicast/broadcast and unknown unicast packets + +Static FDB Entries +^^^^^^^^^^^^^^^^^^ + +A driver which implements the ``ndo_fdb_add``, ``ndo_fdb_del`` and +``ndo_fdb_dump`` operations is able to support the command below, which adds a +static bridge FDB entry:: + + bridge fdb add dev DEV ADDRESS [vlan VID] [self] static + +(the "static" keyword is non-optional: if not specified, the entry defaults to +being "local", which means that it should not be forwarded) + +The "self" keyword (optional because it is implicit) has the role of +instructing the kernel to fulfill the operation through the ``ndo_fdb_add`` +implementation of the ``DEV`` device itself. If ``DEV`` is a bridge port, this +will bypass the bridge and therefore leave the software database out of sync +with the hardware one. + +To avoid this, the "master" keyword can be used:: + + bridge fdb add dev DEV ADDRESS [vlan VID] master static + +The above command instructs the kernel to search for a master interface of +``DEV`` and fulfill the operation through the ``ndo_fdb_add`` method of that. +This time, the bridge generates a ``SWITCHDEV_FDB_ADD_TO_DEVICE`` notification +which the port driver can handle and use it to program its hardware table. This +way, the software and the hardware database will both contain this static FDB +entry. + +Note: for new switchdev drivers that offload the Linux bridge, implementing the +``ndo_fdb_add`` and ``ndo_fdb_del`` bridge bypass methods is strongly +discouraged: all static FDB entries should be added on a bridge port using the +"master" flag. The ``ndo_fdb_dump`` is an exception and can be implemented to +visualize the hardware tables, if the device does not have an interrupt for +notifying the operating system of newly learned/forgotten dynamic FDB +addresses. In that case, the hardware FDB might end up having entries that the +software FDB does not, and implementing ``ndo_fdb_dump`` is the only way to see +them. + +Note: by default, the bridge does not filter on VLAN and only bridges untagged +traffic. To enable VLAN support, turn on VLAN filtering:: + + echo 1 >/sys/class/net/<bridge>/bridge/vlan_filtering + +Notification of Learned/Forgotten Source MAC/VLANs +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The switch device will learn/forget source MAC address/VLAN on ingress packets +and notify the switch driver of the mac/vlan/port tuples. The switch driver, +in turn, will notify the bridge driver using the switchdev notifier call:: + + err = call_switchdev_notifiers(val, dev, info, extack); + +Where val is SWITCHDEV_FDB_ADD when learning and SWITCHDEV_FDB_DEL when +forgetting, and info points to a struct switchdev_notifier_fdb_info. On +SWITCHDEV_FDB_ADD, the bridge driver will install the FDB entry into the +bridge's FDB and mark the entry as NTF_EXT_LEARNED. The iproute2 bridge +command will label these entries "offload":: + + $ bridge fdb + 52:54:00:12:35:01 dev sw1p1 master br0 permanent + 00:02:00:00:02:00 dev sw1p1 master br0 offload + 00:02:00:00:02:00 dev sw1p1 self + 52:54:00:12:35:02 dev sw1p2 master br0 permanent + 00:02:00:00:03:00 dev sw1p2 master br0 offload + 00:02:00:00:03:00 dev sw1p2 self + 33:33:00:00:00:01 dev eth0 self permanent + 01:00:5e:00:00:01 dev eth0 self permanent + 33:33:ff:00:00:00 dev eth0 self permanent + 01:80:c2:00:00:0e dev eth0 self permanent + 33:33:00:00:00:01 dev br0 self permanent + 01:00:5e:00:00:01 dev br0 self permanent + 33:33:ff:12:35:01 dev br0 self permanent + +Learning on the port should be disabled on the bridge using the bridge command:: + + bridge link set dev DEV learning off + +Learning on the device port should be enabled, as well as learning_sync:: + + bridge link set dev DEV learning on self + bridge link set dev DEV learning_sync on self + +Learning_sync attribute enables syncing of the learned/forgotten FDB entry to +the bridge's FDB. It's possible, but not optimal, to enable learning on the +device port and on the bridge port, and disable learning_sync. + +To support learning, the driver implements switchdev op +switchdev_port_attr_set for SWITCHDEV_ATTR_PORT_ID_{PRE}_BRIDGE_FLAGS. + +FDB Ageing +^^^^^^^^^^ + +The bridge will skip ageing FDB entries marked with NTF_EXT_LEARNED and it is +the responsibility of the port driver/device to age out these entries. If the +port device supports ageing, when the FDB entry expires, it will notify the +driver which in turn will notify the bridge with SWITCHDEV_FDB_DEL. If the +device does not support ageing, the driver can simulate ageing using a +garbage collection timer to monitor FDB entries. Expired entries will be +notified to the bridge using SWITCHDEV_FDB_DEL. See rocker driver for +example of driver running ageing timer. + +To keep an NTF_EXT_LEARNED entry "alive", the driver should refresh the FDB +entry by calling call_switchdev_notifiers(SWITCHDEV_FDB_ADD, ...). The +notification will reset the FDB entry's last-used time to now. The driver +should rate limit refresh notifications, for example, no more than once a +second. (The last-used time is visible using the bridge -s fdb option). + +STP State Change on Port +^^^^^^^^^^^^^^^^^^^^^^^^ + +Internally or with a third-party STP protocol implementation (e.g. mstpd), the +bridge driver maintains the STP state for ports, and will notify the switch +driver of STP state change on a port using the switchdev op +switchdev_attr_port_set for SWITCHDEV_ATTR_PORT_ID_STP_UPDATE. + +State is one of BR_STATE_*. The switch driver can use STP state updates to +update ingress packet filter list for the port. For example, if port is +DISABLED, no packets should pass, but if port moves to BLOCKED, then STP BPDUs +and other IEEE 01:80:c2:xx:xx:xx link-local multicast packets can pass. + +Note that STP BDPUs are untagged and STP state applies to all VLANs on the port +so packet filters should be applied consistently across untagged and tagged +VLANs on the port. + +Flooding L2 domain +^^^^^^^^^^^^^^^^^^ + +For a given L2 VLAN domain, the switch device should flood multicast/broadcast +and unknown unicast packets to all ports in domain, if allowed by port's +current STP state. The switch driver, knowing which ports are within which +vlan L2 domain, can program the switch device for flooding. The packet may +be sent to the port netdev for processing by the bridge driver. The +bridge should not reflood the packet to the same ports the device flooded, +otherwise there will be duplicate packets on the wire. + +To avoid duplicate packets, the switch driver should mark a packet as already +forwarded by setting the skb->offload_fwd_mark bit. The bridge driver will mark +the skb using the ingress bridge port's mark and prevent it from being forwarded +through any bridge port with the same mark. + +It is possible for the switch device to not handle flooding and push the +packets up to the bridge driver for flooding. This is not ideal as the number +of ports scale in the L2 domain as the device is much more efficient at +flooding packets that software. + +If supported by the device, flood control can be offloaded to it, preventing +certain netdevs from flooding unicast traffic for which there is no FDB entry. + +IGMP Snooping +^^^^^^^^^^^^^ + +In order to support IGMP snooping, the port netdevs should trap to the bridge +driver all IGMP join and leave messages. +The bridge multicast module will notify port netdevs on every multicast group +changed whether it is static configured or dynamically joined/leave. +The hardware implementation should be forwarding all registered multicast +traffic groups only to the configured ports. + +L3 Routing Offload +------------------ + +Offloading L3 routing requires that device be programmed with FIB entries from +the kernel, with the device doing the FIB lookup and forwarding. The device +does a longest prefix match (LPM) on FIB entries matching route prefix and +forwards the packet to the matching FIB entry's nexthop(s) egress ports. + +To program the device, the driver has to register a FIB notifier handler +using register_fib_notifier. The following events are available: + +=================== =================================================== +FIB_EVENT_ENTRY_ADD used for both adding a new FIB entry to the device, + or modifying an existing entry on the device. +FIB_EVENT_ENTRY_DEL used for removing a FIB entry +FIB_EVENT_RULE_ADD, +FIB_EVENT_RULE_DEL used to propagate FIB rule changes +=================== =================================================== + +FIB_EVENT_ENTRY_ADD and FIB_EVENT_ENTRY_DEL events pass:: + + struct fib_entry_notifier_info { + struct fib_notifier_info info; /* must be first */ + u32 dst; + int dst_len; + struct fib_info *fi; + u8 tos; + u8 type; + u32 tb_id; + u32 nlflags; + }; + +to add/modify/delete IPv4 dst/dest_len prefix on table tb_id. The ``*fi`` +structure holds details on the route and route's nexthops. ``*dev`` is one +of the port netdevs mentioned in the route's next hop list. + +Routes offloaded to the device are labeled with "offload" in the ip route +listing:: + + $ ip route show + default via 192.168.0.2 dev eth0 + 11.0.0.0/30 dev sw1p1 proto kernel scope link src 11.0.0.2 offload + 11.0.0.4/30 via 11.0.0.1 dev sw1p1 proto zebra metric 20 offload + 11.0.0.8/30 dev sw1p2 proto kernel scope link src 11.0.0.10 offload + 11.0.0.12/30 via 11.0.0.9 dev sw1p2 proto zebra metric 20 offload + 12.0.0.2 proto zebra metric 30 offload + nexthop via 11.0.0.1 dev sw1p1 weight 1 + nexthop via 11.0.0.9 dev sw1p2 weight 1 + 12.0.0.3 via 11.0.0.1 dev sw1p1 proto zebra metric 20 offload + 12.0.0.4 via 11.0.0.9 dev sw1p2 proto zebra metric 20 offload + 192.168.0.0/24 dev eth0 proto kernel scope link src 192.168.0.15 + +The "offload" flag is set in case at least one device offloads the FIB entry. + +XXX: add/mod/del IPv6 FIB API + +Nexthop Resolution +^^^^^^^^^^^^^^^^^^ + +The FIB entry's nexthop list contains the nexthop tuple (gateway, dev), but for +the switch device to forward the packet with the correct dst mac address, the +nexthop gateways must be resolved to the neighbor's mac address. Neighbor mac +address discovery comes via the ARP (or ND) process and is available via the +arp_tbl neighbor table. To resolve the routes nexthop gateways, the driver +should trigger the kernel's neighbor resolution process. See the rocker +driver's rocker_port_ipv4_resolve() for an example. + +The driver can monitor for updates to arp_tbl using the netevent notifier +NETEVENT_NEIGH_UPDATE. The device can be programmed with resolved nexthops +for the routes as arp_tbl updates. The driver implements ndo_neigh_destroy +to know when arp_tbl neighbor entries are purged from the port. + +Device driver expected behavior +------------------------------- + +Below is a set of defined behavior that switchdev enabled network devices must +adhere to. + +Configuration-less state +^^^^^^^^^^^^^^^^^^^^^^^^ + +Upon driver bring up, the network devices must be fully operational, and the +backing driver must configure the network device such that it is possible to +send and receive traffic to this network device and it is properly separated +from other network devices/ports (e.g.: as is frequent with a switch ASIC). How +this is achieved is heavily hardware dependent, but a simple solution can be to +use per-port VLAN identifiers unless a better mechanism is available +(proprietary metadata for each network port for instance). + +The network device must be capable of running a full IP protocol stack +including multicast, DHCP, IPv4/6, etc. If necessary, it should program the +appropriate filters for VLAN, multicast, unicast etc. The underlying device +driver must effectively be configured in a similar fashion to what it would do +when IGMP snooping is enabled for IP multicast over these switchdev network +devices and unsolicited multicast must be filtered as early as possible in +the hardware. + +When configuring VLANs on top of the network device, all VLANs must be working, +irrespective of the state of other network devices (e.g.: other ports being part +of a VLAN-aware bridge doing ingress VID checking). See below for details. + +If the device implements e.g.: VLAN filtering, putting the interface in +promiscuous mode should allow the reception of all VLAN tags (including those +not present in the filter(s)). + +Bridged switch ports +^^^^^^^^^^^^^^^^^^^^ + +When a switchdev enabled network device is added as a bridge member, it should +not disrupt any functionality of non-bridged network devices and they +should continue to behave as normal network devices. Depending on the bridge +configuration knobs below, the expected behavior is documented. + +Bridge VLAN filtering +^^^^^^^^^^^^^^^^^^^^^ + +The Linux bridge allows the configuration of a VLAN filtering mode (statically, +at device creation time, and dynamically, during run time) which must be +observed by the underlying switchdev network device/hardware: + +- with VLAN filtering turned off: the bridge is strictly VLAN unaware and its + data path will process all Ethernet frames as if they are VLAN-untagged. + The bridge VLAN database can still be modified, but the modifications should + have no effect while VLAN filtering is turned off. Frames ingressing the + device with a VID that is not programmed into the bridge/switch's VLAN table + must be forwarded and may be processed using a VLAN device (see below). + +- with VLAN filtering turned on: the bridge is VLAN-aware and frames ingressing + the device with a VID that is not programmed into the bridges/switch's VLAN + table must be dropped (strict VID checking). + +When there is a VLAN device (e.g: sw0p1.100) configured on top of a switchdev +network device which is a bridge port member, the behavior of the software +network stack must be preserved, or the configuration must be refused if that +is not possible. + +- with VLAN filtering turned off, the bridge will process all ingress traffic + for the port, except for the traffic tagged with a VLAN ID destined for a + VLAN upper. The VLAN upper interface (which consumes the VLAN tag) can even + be added to a second bridge, which includes other switch ports or software + interfaces. Some approaches to ensure that the forwarding domain for traffic + belonging to the VLAN upper interfaces are managed properly: + + * If forwarding destinations can be managed per VLAN, the hardware could be + configured to map all traffic, except the packets tagged with a VID + belonging to a VLAN upper interface, to an internal VID corresponding to + untagged packets. This internal VID spans all ports of the VLAN-unaware + bridge. The VID corresponding to the VLAN upper interface spans the + physical port of that VLAN interface, as well as the other ports that + might be bridged with it. + * Treat bridge ports with VLAN upper interfaces as standalone, and let + forwarding be handled in the software data path. + +- with VLAN filtering turned on, these VLAN devices can be created as long as + the bridge does not have an existing VLAN entry with the same VID on any + bridge port. These VLAN devices cannot be enslaved into the bridge since they + duplicate functionality/use case with the bridge's VLAN data path processing. + +Non-bridged network ports of the same switch fabric must not be disturbed in any +way by the enabling of VLAN filtering on the bridge device(s). If the VLAN +filtering setting is global to the entire chip, then the standalone ports +should indicate to the network stack that VLAN filtering is required by setting +'rx-vlan-filter: on [fixed]' in the ethtool features. + +Because VLAN filtering can be turned on/off at runtime, the switchdev driver +must be able to reconfigure the underlying hardware on the fly to honor the +toggling of that option and behave appropriately. If that is not possible, the +switchdev driver can also refuse to support dynamic toggling of the VLAN +filtering knob at runtime and require a destruction of the bridge device(s) and +creation of new bridge device(s) with a different VLAN filtering value to +ensure VLAN awareness is pushed down to the hardware. + +Even when VLAN filtering in the bridge is turned off, the underlying switch +hardware and driver may still configure itself in a VLAN-aware mode provided +that the behavior described above is observed. + +The VLAN protocol of the bridge plays a role in deciding whether a packet is +treated as tagged or not: a bridge using the 802.1ad protocol must treat both +VLAN-untagged packets, as well as packets tagged with 802.1Q headers, as +untagged. + +The 802.1p (VID 0) tagged packets must be treated in the same way by the device +as untagged packets, since the bridge device does not allow the manipulation of +VID 0 in its database. + +When the bridge has VLAN filtering enabled and a PVID is not configured on the +ingress port, untagged and 802.1p tagged packets must be dropped. When the bridge +has VLAN filtering enabled and a PVID exists on the ingress port, untagged and +priority-tagged packets must be accepted and forwarded according to the +bridge's port membership of the PVID VLAN. When the bridge has VLAN filtering +disabled, the presence/lack of a PVID should not influence the packet +forwarding decision. + +Bridge IGMP snooping +^^^^^^^^^^^^^^^^^^^^ + +The Linux bridge allows the configuration of IGMP snooping (statically, at +interface creation time, or dynamically, during runtime) which must be observed +by the underlying switchdev network device/hardware in the following way: + +- when IGMP snooping is turned off, multicast traffic must be flooded to all + ports within the same bridge that have mcast_flood=true. The CPU/management + port should ideally not be flooded (unless the ingress interface has + IFF_ALLMULTI or IFF_PROMISC) and continue to learn multicast traffic through + the network stack notifications. If the hardware is not capable of doing that + then the CPU/management port must also be flooded and multicast filtering + happens in software. + +- when IGMP snooping is turned on, multicast traffic must selectively flow + to the appropriate network ports (including CPU/management port). Flooding of + unknown multicast should be only towards the ports connected to a multicast + router (the local device may also act as a multicast router). + +The switch must adhere to RFC 4541 and flood multicast traffic accordingly +since that is what the Linux bridge implementation does. + +Because IGMP snooping can be turned on/off at runtime, the switchdev driver +must be able to reconfigure the underlying hardware on the fly to honor the +toggling of that option and behave appropriately. + +A switchdev driver can also refuse to support dynamic toggling of the multicast +snooping knob at runtime and require the destruction of the bridge device(s) +and creation of a new bridge device(s) with a different multicast snooping +value. diff --git a/Documentation/networking/sysfs-tagging.rst b/Documentation/networking/sysfs-tagging.rst new file mode 100644 index 0000000000..65307130ab --- /dev/null +++ b/Documentation/networking/sysfs-tagging.rst @@ -0,0 +1,48 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============= +Sysfs tagging +============= + +(Taken almost verbatim from Eric Biederman's netns tagging patch +commit msg) + +The problem. Network devices show up in sysfs and with the network +namespace active multiple devices with the same name can show up in +the same directory, ouch! + +To avoid that problem and allow existing applications in network +namespaces to see the same interface that is currently presented in +sysfs, sysfs now has tagging directory support. + +By using the network namespace pointers as tags to separate out +the sysfs directory entries we ensure that we don't have conflicts +in the directories and applications only see a limited set of +the network devices. + +Each sysfs directory entry may be tagged with a namespace via the +``void *ns member`` of its ``kernfs_node``. If a directory entry is tagged, +then ``kernfs_node->flags`` will have a flag between KOBJ_NS_TYPE_NONE +and KOBJ_NS_TYPES, and ns will point to the namespace to which it +belongs. + +Each sysfs superblock's kernfs_super_info contains an array +``void *ns[KOBJ_NS_TYPES]``. When a task in a tagging namespace +kobj_nstype first mounts sysfs, a new superblock is created. It +will be differentiated from other sysfs mounts by having its +``s_fs_info->ns[kobj_nstype]`` set to the new namespace. Note that +through bind mounting and mounts propagation, a task can easily view +the contents of other namespaces' sysfs mounts. Therefore, when a +namespace exits, it will call kobj_ns_exit() to invalidate any +kernfs_node->ns pointers pointing to it. + +Users of this interface: + +- define a type in the ``kobj_ns_type`` enumeration. +- call kobj_ns_type_register() with its ``kobj_ns_type_operations`` which has + + - current_ns() which returns current's namespace + - netlink_ns() which returns a socket's namespace + - initial_ns() which returns the initial namespace + +- call kobj_ns_exit() when an individual tag is no longer valid diff --git a/Documentation/networking/tc-actions-env-rules.rst b/Documentation/networking/tc-actions-env-rules.rst new file mode 100644 index 0000000000..86884b8fb4 --- /dev/null +++ b/Documentation/networking/tc-actions-env-rules.rst @@ -0,0 +1,29 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================================ +TC Actions - Environmental Rules +================================ + + +The "environmental" rules for authors of any new tc actions are: + +1) If you stealeth or borroweth any packet thou shalt be branching + from the righteous path and thou shalt cloneth. + + For example if your action queues a packet to be processed later, + or intentionally branches by redirecting a packet, then you need to + clone the packet. + +2) If you munge any packet thou shalt call pskb_expand_head in the case + someone else is referencing the skb. After that you "own" the skb. + +3) Dropping packets you don't own is a no-no. You simply return + TC_ACT_SHOT to the caller and they will drop it. + +The "environmental" rules for callers of actions (qdiscs etc) are: + +#) Thou art responsible for freeing anything returned as being + TC_ACT_SHOT/STOLEN/QUEUED. If none of TC_ACT_SHOT/STOLEN/QUEUED is + returned, then all is great and you don't need to do anything. + +Post on netdev if something is unclear. diff --git a/Documentation/networking/tc-queue-filters.rst b/Documentation/networking/tc-queue-filters.rst new file mode 100644 index 0000000000..6b41709227 --- /dev/null +++ b/Documentation/networking/tc-queue-filters.rst @@ -0,0 +1,37 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================= +TC queue based filtering +========================= + +TC can be used for directing traffic to either a set of queues or +to a single queue on both the transmit and receive side. + +On the transmit side: + +1) TC filter directing traffic to a set of queues is achieved + using the action skbedit priority for Tx priority selection, + the priority maps to a traffic class (set of queues) when + the queue-sets are configured using mqprio. + +2) TC filter directs traffic to a transmit queue with the action + skbedit queue_mapping $tx_qid. The action skbedit queue_mapping + for transmit queue is executed in software only and cannot be + offloaded. + +Likewise, on the receive side, the two filters for selecting set of +queues and/or a single queue are supported as below: + +1) TC flower filter directs incoming traffic to a set of queues using + the 'hw_tc' option. + hw_tc $TCID - Specify a hardware traffic class to pass matching + packets on to. TCID is in the range 0 through 15. + +2) TC filter with action skbedit queue_mapping $rx_qid selects a + receive queue. The action skbedit queue_mapping for receive queue + is supported only in hardware. Multiple filters may compete in + the hardware for queue selection. In such case, the hardware + pipeline resolves conflicts based on priority. On Intel E810 + devices, TC filter directing traffic to a queue have higher + priority over flow director filter assigning a queue. The hash + filter has lowest priority. diff --git a/Documentation/networking/tcp-thin.rst b/Documentation/networking/tcp-thin.rst new file mode 100644 index 0000000000..b06765c96e --- /dev/null +++ b/Documentation/networking/tcp-thin.rst @@ -0,0 +1,52 @@ +.. SPDX-License-Identifier: GPL-2.0 + +==================== +Thin-streams and TCP +==================== + +A wide range of Internet-based services that use reliable transport +protocols display what we call thin-stream properties. This means +that the application sends data with such a low rate that the +retransmission mechanisms of the transport protocol are not fully +effective. In time-dependent scenarios (like online games, control +systems, stock trading etc.) where the user experience depends +on the data delivery latency, packet loss can be devastating for +the service quality. Extreme latencies are caused by TCP's +dependency on the arrival of new data from the application to trigger +retransmissions effectively through fast retransmit instead of +waiting for long timeouts. + +After analysing a large number of time-dependent interactive +applications, we have seen that they often produce thin streams +and also stay with this traffic pattern throughout its entire +lifespan. The combination of time-dependency and the fact that the +streams provoke high latencies when using TCP is unfortunate. + +In order to reduce application-layer latency when packets are lost, +a set of mechanisms has been made, which address these latency issues +for thin streams. In short, if the kernel detects a thin stream, +the retransmission mechanisms are modified in the following manner: + +1) If the stream is thin, fast retransmit on the first dupACK. +2) If the stream is thin, do not apply exponential backoff. + +These enhancements are applied only if the stream is detected as +thin. This is accomplished by defining a threshold for the number +of packets in flight. If there are less than 4 packets in flight, +fast retransmissions can not be triggered, and the stream is prone +to experience high retransmission latencies. + +Since these mechanisms are targeted at time-dependent applications, +they must be specifically activated by the application using the +TCP_THIN_LINEAR_TIMEOUTS and TCP_THIN_DUPACK IOCTLS or the +tcp_thin_linear_timeouts and tcp_thin_dupack sysctls. Both +modifications are turned off by default. + +References +========== +More information on the modifications, as well as a wide range of +experimental data can be found here: + +"Improving latency for interactive, thin-stream applications over +reliable transport" +http://simula.no/research/nd/publications/Simula.nd.477/simula_pdf_file diff --git a/Documentation/networking/team.rst b/Documentation/networking/team.rst new file mode 100644 index 0000000000..0a7f3a0595 --- /dev/null +++ b/Documentation/networking/team.rst @@ -0,0 +1,8 @@ +.. SPDX-License-Identifier: GPL-2.0 + +==== +Team +==== + +Team devices are driven from userspace via libteam library which is here: + https://github.com/jpirko/libteam diff --git a/Documentation/networking/timestamping.rst b/Documentation/networking/timestamping.rst new file mode 100644 index 0000000000..f17c01834a --- /dev/null +++ b/Documentation/networking/timestamping.rst @@ -0,0 +1,802 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============ +Timestamping +============ + + +1. Control Interfaces +===================== + +The interfaces for receiving network packages timestamps are: + +SO_TIMESTAMP + Generates a timestamp for each incoming packet in (not necessarily + monotonic) system time. Reports the timestamp via recvmsg() in a + control message in usec resolution. + SO_TIMESTAMP is defined as SO_TIMESTAMP_NEW or SO_TIMESTAMP_OLD + based on the architecture type and time_t representation of libc. + Control message format is in struct __kernel_old_timeval for + SO_TIMESTAMP_OLD and in struct __kernel_sock_timeval for + SO_TIMESTAMP_NEW options respectively. + +SO_TIMESTAMPNS + Same timestamping mechanism as SO_TIMESTAMP, but reports the + timestamp as struct timespec in nsec resolution. + SO_TIMESTAMPNS is defined as SO_TIMESTAMPNS_NEW or SO_TIMESTAMPNS_OLD + based on the architecture type and time_t representation of libc. + Control message format is in struct timespec for SO_TIMESTAMPNS_OLD + and in struct __kernel_timespec for SO_TIMESTAMPNS_NEW options + respectively. + +IP_MULTICAST_LOOP + SO_TIMESTAMP[NS] + Only for multicast:approximate transmit timestamp obtained by + reading the looped packet receive timestamp. + +SO_TIMESTAMPING + Generates timestamps on reception, transmission or both. Supports + multiple timestamp sources, including hardware. Supports generating + timestamps for stream sockets. + + +1.1 SO_TIMESTAMP (also SO_TIMESTAMP_OLD and SO_TIMESTAMP_NEW) +------------------------------------------------------------- + +This socket option enables timestamping of datagrams on the reception +path. Because the destination socket, if any, is not known early in +the network stack, the feature has to be enabled for all packets. The +same is true for all early receive timestamp options. + +For interface details, see `man 7 socket`. + +Always use SO_TIMESTAMP_NEW timestamp to always get timestamp in +struct __kernel_sock_timeval format. + +SO_TIMESTAMP_OLD returns incorrect timestamps after the year 2038 +on 32 bit machines. + +1.2 SO_TIMESTAMPNS (also SO_TIMESTAMPNS_OLD and SO_TIMESTAMPNS_NEW) +------------------------------------------------------------------- + +This option is identical to SO_TIMESTAMP except for the returned data type. +Its struct timespec allows for higher resolution (ns) timestamps than the +timeval of SO_TIMESTAMP (ms). + +Always use SO_TIMESTAMPNS_NEW timestamp to always get timestamp in +struct __kernel_timespec format. + +SO_TIMESTAMPNS_OLD returns incorrect timestamps after the year 2038 +on 32 bit machines. + +1.3 SO_TIMESTAMPING (also SO_TIMESTAMPING_OLD and SO_TIMESTAMPING_NEW) +---------------------------------------------------------------------- + +Supports multiple types of timestamp requests. As a result, this +socket option takes a bitmap of flags, not a boolean. In:: + + err = setsockopt(fd, SOL_SOCKET, SO_TIMESTAMPING, &val, sizeof(val)); + +val is an integer with any of the following bits set. Setting other +bit returns EINVAL and does not change the current state. + +The socket option configures timestamp generation for individual +sk_buffs (1.3.1), timestamp reporting to the socket's error +queue (1.3.2) and options (1.3.3). Timestamp generation can also +be enabled for individual sendmsg calls using cmsg (1.3.4). + + +1.3.1 Timestamp Generation +^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Some bits are requests to the stack to try to generate timestamps. Any +combination of them is valid. Changes to these bits apply to newly +created packets, not to packets already in the stack. As a result, it +is possible to selectively request timestamps for a subset of packets +(e.g., for sampling) by embedding an send() call within two setsockopt +calls, one to enable timestamp generation and one to disable it. +Timestamps may also be generated for reasons other than being +requested by a particular socket, such as when receive timestamping is +enabled system wide, as explained earlier. + +SOF_TIMESTAMPING_RX_HARDWARE: + Request rx timestamps generated by the network adapter. + +SOF_TIMESTAMPING_RX_SOFTWARE: + Request rx timestamps when data enters the kernel. These timestamps + are generated just after a device driver hands a packet to the + kernel receive stack. + +SOF_TIMESTAMPING_TX_HARDWARE: + Request tx timestamps generated by the network adapter. This flag + can be enabled via both socket options and control messages. + +SOF_TIMESTAMPING_TX_SOFTWARE: + Request tx timestamps when data leaves the kernel. These timestamps + are generated in the device driver as close as possible, but always + prior to, passing the packet to the network interface. Hence, they + require driver support and may not be available for all devices. + This flag can be enabled via both socket options and control messages. + +SOF_TIMESTAMPING_TX_SCHED: + Request tx timestamps prior to entering the packet scheduler. Kernel + transmit latency is, if long, often dominated by queuing delay. The + difference between this timestamp and one taken at + SOF_TIMESTAMPING_TX_SOFTWARE will expose this latency independent + of protocol processing. The latency incurred in protocol + processing, if any, can be computed by subtracting a userspace + timestamp taken immediately before send() from this timestamp. On + machines with virtual devices where a transmitted packet travels + through multiple devices and, hence, multiple packet schedulers, + a timestamp is generated at each layer. This allows for fine + grained measurement of queuing delay. This flag can be enabled + via both socket options and control messages. + +SOF_TIMESTAMPING_TX_ACK: + Request tx timestamps when all data in the send buffer has been + acknowledged. This only makes sense for reliable protocols. It is + currently only implemented for TCP. For that protocol, it may + over-report measurement, because the timestamp is generated when all + data up to and including the buffer at send() was acknowledged: the + cumulative acknowledgment. The mechanism ignores SACK and FACK. + This flag can be enabled via both socket options and control messages. + + +1.3.2 Timestamp Reporting +^^^^^^^^^^^^^^^^^^^^^^^^^ + +The other three bits control which timestamps will be reported in a +generated control message. Changes to the bits take immediate +effect at the timestamp reporting locations in the stack. Timestamps +are only reported for packets that also have the relevant timestamp +generation request set. + +SOF_TIMESTAMPING_SOFTWARE: + Report any software timestamps when available. + +SOF_TIMESTAMPING_SYS_HARDWARE: + This option is deprecated and ignored. + +SOF_TIMESTAMPING_RAW_HARDWARE: + Report hardware timestamps as generated by + SOF_TIMESTAMPING_TX_HARDWARE when available. + + +1.3.3 Timestamp Options +^^^^^^^^^^^^^^^^^^^^^^^ + +The interface supports the options + +SOF_TIMESTAMPING_OPT_ID: + Generate a unique identifier along with each packet. A process can + have multiple concurrent timestamping requests outstanding. Packets + can be reordered in the transmit path, for instance in the packet + scheduler. In that case timestamps will be queued onto the error + queue out of order from the original send() calls. It is not always + possible to uniquely match timestamps to the original send() calls + based on timestamp order or payload inspection alone, then. + + This option associates each packet at send() with a unique + identifier and returns that along with the timestamp. The identifier + is derived from a per-socket u32 counter (that wraps). For datagram + sockets, the counter increments with each sent packet. For stream + sockets, it increments with every byte. For stream sockets, also set + SOF_TIMESTAMPING_OPT_ID_TCP, see the section below. + + The counter starts at zero. It is initialized the first time that + the socket option is enabled. It is reset each time the option is + enabled after having been disabled. Resetting the counter does not + change the identifiers of existing packets in the system. + + This option is implemented only for transmit timestamps. There, the + timestamp is always looped along with a struct sock_extended_err. + The option modifies field ee_data to pass an id that is unique + among all possibly concurrently outstanding timestamp requests for + that socket. + +SOF_TIMESTAMPING_OPT_ID_TCP: + Pass this modifier along with SOF_TIMESTAMPING_OPT_ID for new TCP + timestamping applications. SOF_TIMESTAMPING_OPT_ID defines how the + counter increments for stream sockets, but its starting point is + not entirely trivial. This option fixes that. + + For stream sockets, if SOF_TIMESTAMPING_OPT_ID is set, this should + always be set too. On datagram sockets the option has no effect. + + A reasonable expectation is that the counter is reset to zero with + the system call, so that a subsequent write() of N bytes generates + a timestamp with counter N-1. SOF_TIMESTAMPING_OPT_ID_TCP + implements this behavior under all conditions. + + SOF_TIMESTAMPING_OPT_ID without modifier often reports the same, + especially when the socket option is set when no data is in + transmission. If data is being transmitted, it may be off by the + length of the output queue (SIOCOUTQ). + + The difference is due to being based on snd_una versus write_seq. + snd_una is the offset in the stream acknowledged by the peer. This + depends on factors outside of process control, such as network RTT. + write_seq is the last byte written by the process. This offset is + not affected by external inputs. + + The difference is subtle and unlikely to be noticed when configured + at initial socket creation, when no data is queued or sent. But + SOF_TIMESTAMPING_OPT_ID_TCP behavior is more robust regardless of + when the socket option is set. + +SOF_TIMESTAMPING_OPT_CMSG: + Support recv() cmsg for all timestamped packets. Control messages + are already supported unconditionally on all packets with receive + timestamps and on IPv6 packets with transmit timestamp. This option + extends them to IPv4 packets with transmit timestamp. One use case + is to correlate packets with their egress device, by enabling socket + option IP_PKTINFO simultaneously. + + +SOF_TIMESTAMPING_OPT_TSONLY: + Applies to transmit timestamps only. Makes the kernel return the + timestamp as a cmsg alongside an empty packet, as opposed to + alongside the original packet. This reduces the amount of memory + charged to the socket's receive budget (SO_RCVBUF) and delivers + the timestamp even if sysctl net.core.tstamp_allow_data is 0. + This option disables SOF_TIMESTAMPING_OPT_CMSG. + +SOF_TIMESTAMPING_OPT_STATS: + Optional stats that are obtained along with the transmit timestamps. + It must be used together with SOF_TIMESTAMPING_OPT_TSONLY. When the + transmit timestamp is available, the stats are available in a + separate control message of type SCM_TIMESTAMPING_OPT_STATS, as a + list of TLVs (struct nlattr) of types. These stats allow the + application to associate various transport layer stats with + the transmit timestamps, such as how long a certain block of + data was limited by peer's receiver window. + +SOF_TIMESTAMPING_OPT_PKTINFO: + Enable the SCM_TIMESTAMPING_PKTINFO control message for incoming + packets with hardware timestamps. The message contains struct + scm_ts_pktinfo, which supplies the index of the real interface which + received the packet and its length at layer 2. A valid (non-zero) + interface index will be returned only if CONFIG_NET_RX_BUSY_POLL is + enabled and the driver is using NAPI. The struct contains also two + other fields, but they are reserved and undefined. + +SOF_TIMESTAMPING_OPT_TX_SWHW: + Request both hardware and software timestamps for outgoing packets + when SOF_TIMESTAMPING_TX_HARDWARE and SOF_TIMESTAMPING_TX_SOFTWARE + are enabled at the same time. If both timestamps are generated, + two separate messages will be looped to the socket's error queue, + each containing just one timestamp. + +New applications are encouraged to pass SOF_TIMESTAMPING_OPT_ID to +disambiguate timestamps and SOF_TIMESTAMPING_OPT_TSONLY to operate +regardless of the setting of sysctl net.core.tstamp_allow_data. + +An exception is when a process needs additional cmsg data, for +instance SOL_IP/IP_PKTINFO to detect the egress network interface. +Then pass option SOF_TIMESTAMPING_OPT_CMSG. This option depends on +having access to the contents of the original packet, so cannot be +combined with SOF_TIMESTAMPING_OPT_TSONLY. + + +1.3.4. Enabling timestamps via control messages +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +In addition to socket options, timestamp generation can be requested +per write via cmsg, only for SOF_TIMESTAMPING_TX_* (see Section 1.3.1). +Using this feature, applications can sample timestamps per sendmsg() +without paying the overhead of enabling and disabling timestamps via +setsockopt:: + + struct msghdr *msg; + ... + cmsg = CMSG_FIRSTHDR(msg); + cmsg->cmsg_level = SOL_SOCKET; + cmsg->cmsg_type = SO_TIMESTAMPING; + cmsg->cmsg_len = CMSG_LEN(sizeof(__u32)); + *((__u32 *) CMSG_DATA(cmsg)) = SOF_TIMESTAMPING_TX_SCHED | + SOF_TIMESTAMPING_TX_SOFTWARE | + SOF_TIMESTAMPING_TX_ACK; + err = sendmsg(fd, msg, 0); + +The SOF_TIMESTAMPING_TX_* flags set via cmsg will override +the SOF_TIMESTAMPING_TX_* flags set via setsockopt. + +Moreover, applications must still enable timestamp reporting via +setsockopt to receive timestamps:: + + __u32 val = SOF_TIMESTAMPING_SOFTWARE | + SOF_TIMESTAMPING_OPT_ID /* or any other flag */; + err = setsockopt(fd, SOL_SOCKET, SO_TIMESTAMPING, &val, sizeof(val)); + + +1.4 Bytestream Timestamps +------------------------- + +The SO_TIMESTAMPING interface supports timestamping of bytes in a +bytestream. Each request is interpreted as a request for when the +entire contents of the buffer has passed a timestamping point. That +is, for streams option SOF_TIMESTAMPING_TX_SOFTWARE will record +when all bytes have reached the device driver, regardless of how +many packets the data has been converted into. + +In general, bytestreams have no natural delimiters and therefore +correlating a timestamp with data is non-trivial. A range of bytes +may be split across segments, any segments may be merged (possibly +coalescing sections of previously segmented buffers associated with +independent send() calls). Segments can be reordered and the same +byte range can coexist in multiple segments for protocols that +implement retransmissions. + +It is essential that all timestamps implement the same semantics, +regardless of these possible transformations, as otherwise they are +incomparable. Handling "rare" corner cases differently from the +simple case (a 1:1 mapping from buffer to skb) is insufficient +because performance debugging often needs to focus on such outliers. + +In practice, timestamps can be correlated with segments of a +bytestream consistently, if both semantics of the timestamp and the +timing of measurement are chosen correctly. This challenge is no +different from deciding on a strategy for IP fragmentation. There, the +definition is that only the first fragment is timestamped. For +bytestreams, we chose that a timestamp is generated only when all +bytes have passed a point. SOF_TIMESTAMPING_TX_ACK as defined is easy to +implement and reason about. An implementation that has to take into +account SACK would be more complex due to possible transmission holes +and out of order arrival. + +On the host, TCP can also break the simple 1:1 mapping from buffer to +skbuff as a result of Nagle, cork, autocork, segmentation and GSO. The +implementation ensures correctness in all cases by tracking the +individual last byte passed to send(), even if it is no longer the +last byte after an skbuff extend or merge operation. It stores the +relevant sequence number in skb_shinfo(skb)->tskey. Because an skbuff +has only one such field, only one timestamp can be generated. + +In rare cases, a timestamp request can be missed if two requests are +collapsed onto the same skb. A process can detect this situation by +enabling SOF_TIMESTAMPING_OPT_ID and comparing the byte offset at +send time with the value returned for each timestamp. It can prevent +the situation by always flushing the TCP stack in between requests, +for instance by enabling TCP_NODELAY and disabling TCP_CORK and +autocork. + +These precautions ensure that the timestamp is generated only when all +bytes have passed a timestamp point, assuming that the network stack +itself does not reorder the segments. The stack indeed tries to avoid +reordering. The one exception is under administrator control: it is +possible to construct a packet scheduler configuration that delays +segments from the same stream differently. Such a setup would be +unusual. + + +2 Data Interfaces +================== + +Timestamps are read using the ancillary data feature of recvmsg(). +See `man 3 cmsg` for details of this interface. The socket manual +page (`man 7 socket`) describes how timestamps generated with +SO_TIMESTAMP and SO_TIMESTAMPNS records can be retrieved. + + +2.1 SCM_TIMESTAMPING records +---------------------------- + +These timestamps are returned in a control message with cmsg_level +SOL_SOCKET, cmsg_type SCM_TIMESTAMPING, and payload of type + +For SO_TIMESTAMPING_OLD:: + + struct scm_timestamping { + struct timespec ts[3]; + }; + +For SO_TIMESTAMPING_NEW:: + + struct scm_timestamping64 { + struct __kernel_timespec ts[3]; + +Always use SO_TIMESTAMPING_NEW timestamp to always get timestamp in +struct scm_timestamping64 format. + +SO_TIMESTAMPING_OLD returns incorrect timestamps after the year 2038 +on 32 bit machines. + +The structure can return up to three timestamps. This is a legacy +feature. At least one field is non-zero at any time. Most timestamps +are passed in ts[0]. Hardware timestamps are passed in ts[2]. + +ts[1] used to hold hardware timestamps converted to system time. +Instead, expose the hardware clock device on the NIC directly as +a HW PTP clock source, to allow time conversion in userspace and +optionally synchronize system time with a userspace PTP stack such +as linuxptp. For the PTP clock API, see Documentation/driver-api/ptp.rst. + +Note that if the SO_TIMESTAMP or SO_TIMESTAMPNS option is enabled +together with SO_TIMESTAMPING using SOF_TIMESTAMPING_SOFTWARE, a false +software timestamp will be generated in the recvmsg() call and passed +in ts[0] when a real software timestamp is missing. This happens also +on hardware transmit timestamps. + +2.1.1 Transmit timestamps with MSG_ERRQUEUE +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +For transmit timestamps the outgoing packet is looped back to the +socket's error queue with the send timestamp(s) attached. A process +receives the timestamps by calling recvmsg() with flag MSG_ERRQUEUE +set and with a msg_control buffer sufficiently large to receive the +relevant metadata structures. The recvmsg call returns the original +outgoing data packet with two ancillary messages attached. + +A message of cm_level SOL_IP(V6) and cm_type IP(V6)_RECVERR +embeds a struct sock_extended_err. This defines the error type. For +timestamps, the ee_errno field is ENOMSG. The other ancillary message +will have cm_level SOL_SOCKET and cm_type SCM_TIMESTAMPING. This +embeds the struct scm_timestamping. + + +2.1.1.2 Timestamp types +~~~~~~~~~~~~~~~~~~~~~~~ + +The semantics of the three struct timespec are defined by field +ee_info in the extended error structure. It contains a value of +type SCM_TSTAMP_* to define the actual timestamp passed in +scm_timestamping. + +The SCM_TSTAMP_* types are 1:1 matches to the SOF_TIMESTAMPING_* +control fields discussed previously, with one exception. For legacy +reasons, SCM_TSTAMP_SND is equal to zero and can be set for both +SOF_TIMESTAMPING_TX_HARDWARE and SOF_TIMESTAMPING_TX_SOFTWARE. It +is the first if ts[2] is non-zero, the second otherwise, in which +case the timestamp is stored in ts[0]. + + +2.1.1.3 Fragmentation +~~~~~~~~~~~~~~~~~~~~~ + +Fragmentation of outgoing datagrams is rare, but is possible, e.g., by +explicitly disabling PMTU discovery. If an outgoing packet is fragmented, +then only the first fragment is timestamped and returned to the sending +socket. + + +2.1.1.4 Packet Payload +~~~~~~~~~~~~~~~~~~~~~~ + +The calling application is often not interested in receiving the whole +packet payload that it passed to the stack originally: the socket +error queue mechanism is just a method to piggyback the timestamp on. +In this case, the application can choose to read datagrams with a +smaller buffer, possibly even of length 0. The payload is truncated +accordingly. Until the process calls recvmsg() on the error queue, +however, the full packet is queued, taking up budget from SO_RCVBUF. + + +2.1.1.5 Blocking Read +~~~~~~~~~~~~~~~~~~~~~ + +Reading from the error queue is always a non-blocking operation. To +block waiting on a timestamp, use poll or select. poll() will return +POLLERR in pollfd.revents if any data is ready on the error queue. +There is no need to pass this flag in pollfd.events. This flag is +ignored on request. See also `man 2 poll`. + + +2.1.2 Receive timestamps +^^^^^^^^^^^^^^^^^^^^^^^^ + +On reception, there is no reason to read from the socket error queue. +The SCM_TIMESTAMPING ancillary data is sent along with the packet data +on a normal recvmsg(). Since this is not a socket error, it is not +accompanied by a message SOL_IP(V6)/IP(V6)_RECVERROR. In this case, +the meaning of the three fields in struct scm_timestamping is +implicitly defined. ts[0] holds a software timestamp if set, ts[1] +is again deprecated and ts[2] holds a hardware timestamp if set. + + +3. Hardware Timestamping configuration: SIOCSHWTSTAMP and SIOCGHWTSTAMP +======================================================================= + +Hardware time stamping must also be initialized for each device driver +that is expected to do hardware time stamping. The parameter is defined in +include/uapi/linux/net_tstamp.h as:: + + struct hwtstamp_config { + int flags; /* no flags defined right now, must be zero */ + int tx_type; /* HWTSTAMP_TX_* */ + int rx_filter; /* HWTSTAMP_FILTER_* */ + }; + +Desired behavior is passed into the kernel and to a specific device by +calling ioctl(SIOCSHWTSTAMP) with a pointer to a struct ifreq whose +ifr_data points to a struct hwtstamp_config. The tx_type and +rx_filter are hints to the driver what it is expected to do. If +the requested fine-grained filtering for incoming packets is not +supported, the driver may time stamp more than just the requested types +of packets. + +Drivers are free to use a more permissive configuration than the requested +configuration. It is expected that drivers should only implement directly the +most generic mode that can be supported. For example if the hardware can +support HWTSTAMP_FILTER_PTP_V2_EVENT, then it should generally always upscale +HWTSTAMP_FILTER_PTP_V2_L2_SYNC, and so forth, as HWTSTAMP_FILTER_PTP_V2_EVENT +is more generic (and more useful to applications). + +A driver which supports hardware time stamping shall update the struct +with the actual, possibly more permissive configuration. If the +requested packets cannot be time stamped, then nothing should be +changed and ERANGE shall be returned (in contrast to EINVAL, which +indicates that SIOCSHWTSTAMP is not supported at all). + +Only a processes with admin rights may change the configuration. User +space is responsible to ensure that multiple processes don't interfere +with each other and that the settings are reset. + +Any process can read the actual configuration by passing this +structure to ioctl(SIOCGHWTSTAMP) in the same way. However, this has +not been implemented in all drivers. + +:: + + /* possible values for hwtstamp_config->tx_type */ + enum { + /* + * no outgoing packet will need hardware time stamping; + * should a packet arrive which asks for it, no hardware + * time stamping will be done + */ + HWTSTAMP_TX_OFF, + + /* + * enables hardware time stamping for outgoing packets; + * the sender of the packet decides which are to be + * time stamped by setting SOF_TIMESTAMPING_TX_SOFTWARE + * before sending the packet + */ + HWTSTAMP_TX_ON, + }; + + /* possible values for hwtstamp_config->rx_filter */ + enum { + /* time stamp no incoming packet at all */ + HWTSTAMP_FILTER_NONE, + + /* time stamp any incoming packet */ + HWTSTAMP_FILTER_ALL, + + /* return value: time stamp all packets requested plus some others */ + HWTSTAMP_FILTER_SOME, + + /* PTP v1, UDP, any kind of event packet */ + HWTSTAMP_FILTER_PTP_V1_L4_EVENT, + + /* for the complete list of values, please check + * the include file include/uapi/linux/net_tstamp.h + */ + }; + +3.1 Hardware Timestamping Implementation: Device Drivers +-------------------------------------------------------- + +A driver which supports hardware time stamping must support the +SIOCSHWTSTAMP ioctl and update the supplied struct hwtstamp_config with +the actual values as described in the section on SIOCSHWTSTAMP. It +should also support SIOCGHWTSTAMP. + +Time stamps for received packets must be stored in the skb. To get a pointer +to the shared time stamp structure of the skb call skb_hwtstamps(). Then +set the time stamps in the structure:: + + struct skb_shared_hwtstamps { + /* hardware time stamp transformed into duration + * since arbitrary point in time + */ + ktime_t hwtstamp; + }; + +Time stamps for outgoing packets are to be generated as follows: + +- In hard_start_xmit(), check if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) + is set no-zero. If yes, then the driver is expected to do hardware time + stamping. +- If this is possible for the skb and requested, then declare + that the driver is doing the time stamping by setting the flag + SKBTX_IN_PROGRESS in skb_shinfo(skb)->tx_flags , e.g. with:: + + skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS; + + You might want to keep a pointer to the associated skb for the next step + and not free the skb. A driver not supporting hardware time stamping doesn't + do that. A driver must never touch sk_buff::tstamp! It is used to store + software generated time stamps by the network subsystem. +- Driver should call skb_tx_timestamp() as close to passing sk_buff to hardware + as possible. skb_tx_timestamp() provides a software time stamp if requested + and hardware timestamping is not possible (SKBTX_IN_PROGRESS not set). +- As soon as the driver has sent the packet and/or obtained a + hardware time stamp for it, it passes the time stamp back by + calling skb_tstamp_tx() with the original skb, the raw + hardware time stamp. skb_tstamp_tx() clones the original skb and + adds the timestamps, therefore the original skb has to be freed now. + If obtaining the hardware time stamp somehow fails, then the driver + should not fall back to software time stamping. The rationale is that + this would occur at a later time in the processing pipeline than other + software time stamping and therefore could lead to unexpected deltas + between time stamps. + +3.2 Special considerations for stacked PTP Hardware Clocks +---------------------------------------------------------- + +There are situations when there may be more than one PHC (PTP Hardware Clock) +in the data path of a packet. The kernel has no explicit mechanism to allow the +user to select which PHC to use for timestamping Ethernet frames. Instead, the +assumption is that the outermost PHC is always the most preferable, and that +kernel drivers collaborate towards achieving that goal. Currently there are 3 +cases of stacked PHCs, detailed below: + +3.2.1 DSA (Distributed Switch Architecture) switches +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +These are Ethernet switches which have one of their ports connected to an +(otherwise completely unaware) host Ethernet interface, and perform the role of +a port multiplier with optional forwarding acceleration features. Each DSA +switch port is visible to the user as a standalone (virtual) network interface, +and its network I/O is performed, under the hood, indirectly through the host +interface (redirecting to the host port on TX, and intercepting frames on RX). + +When a DSA switch is attached to a host port, PTP synchronization has to +suffer, since the switch's variable queuing delay introduces a path delay +jitter between the host port and its PTP partner. For this reason, some DSA +switches include a timestamping clock of their own, and have the ability to +perform network timestamping on their own MAC, such that path delays only +measure wire and PHY propagation latencies. Timestamping DSA switches are +supported in Linux and expose the same ABI as any other network interface (save +for the fact that the DSA interfaces are in fact virtual in terms of network +I/O, they do have their own PHC). It is typical, but not mandatory, for all +interfaces of a DSA switch to share the same PHC. + +By design, PTP timestamping with a DSA switch does not need any special +handling in the driver for the host port it is attached to. However, when the +host port also supports PTP timestamping, DSA will take care of intercepting +the ``.ndo_eth_ioctl`` calls towards the host port, and block attempts to enable +hardware timestamping on it. This is because the SO_TIMESTAMPING API does not +allow the delivery of multiple hardware timestamps for the same packet, so +anybody else except for the DSA switch port must be prevented from doing so. + +In the generic layer, DSA provides the following infrastructure for PTP +timestamping: + +- ``.port_txtstamp()``: a hook called prior to the transmission of + packets with a hardware TX timestamping request from user space. + This is required for two-step timestamping, since the hardware + timestamp becomes available after the actual MAC transmission, so the + driver must be prepared to correlate the timestamp with the original + packet so that it can re-enqueue the packet back into the socket's + error queue. To save the packet for when the timestamp becomes + available, the driver can call ``skb_clone_sk`` , save the clone pointer + in skb->cb and enqueue a tx skb queue. Typically, a switch will have a + PTP TX timestamp register (or sometimes a FIFO) where the timestamp + becomes available. In case of a FIFO, the hardware might store + key-value pairs of PTP sequence ID/message type/domain number and the + actual timestamp. To perform the correlation correctly between the + packets in a queue waiting for timestamping and the actual timestamps, + drivers can use a BPF classifier (``ptp_classify_raw``) to identify + the PTP transport type, and ``ptp_parse_header`` to interpret the PTP + header fields. There may be an IRQ that is raised upon this + timestamp's availability, or the driver might have to poll after + invoking ``dev_queue_xmit()`` towards the host interface. + One-step TX timestamping do not require packet cloning, since there is + no follow-up message required by the PTP protocol (because the + TX timestamp is embedded into the packet by the MAC), and therefore + user space does not expect the packet annotated with the TX timestamp + to be re-enqueued into its socket's error queue. + +- ``.port_rxtstamp()``: On RX, the BPF classifier is run by DSA to + identify PTP event messages (any other packets, including PTP general + messages, are not timestamped). The original (and only) timestampable + skb is provided to the driver, for it to annotate it with a timestamp, + if that is immediately available, or defer to later. On reception, + timestamps might either be available in-band (through metadata in the + DSA header, or attached in other ways to the packet), or out-of-band + (through another RX timestamping FIFO). Deferral on RX is typically + necessary when retrieving the timestamp needs a sleepable context. In + that case, it is the responsibility of the DSA driver to call + ``netif_rx()`` on the freshly timestamped skb. + +3.2.2 Ethernet PHYs +^^^^^^^^^^^^^^^^^^^ + +These are devices that typically fulfill a Layer 1 role in the network stack, +hence they do not have a representation in terms of a network interface as DSA +switches do. However, PHYs may be able to detect and timestamp PTP packets, for +performance reasons: timestamps taken as close as possible to the wire have the +potential to yield a more stable and precise synchronization. + +A PHY driver that supports PTP timestamping must create a ``struct +mii_timestamper`` and add a pointer to it in ``phydev->mii_ts``. The presence +of this pointer will be checked by the networking stack. + +Since PHYs do not have network interface representations, the timestamping and +ethtool ioctl operations for them need to be mediated by their respective MAC +driver. Therefore, as opposed to DSA switches, modifications need to be done +to each individual MAC driver for PHY timestamping support. This entails: + +- Checking, in ``.ndo_eth_ioctl``, whether ``phy_has_hwtstamp(netdev->phydev)`` + is true or not. If it is, then the MAC driver should not process this request + but instead pass it on to the PHY using ``phy_mii_ioctl()``. + +- On RX, special intervention may or may not be needed, depending on the + function used to deliver skb's up the network stack. In the case of plain + ``netif_rx()`` and similar, MAC drivers must check whether + ``skb_defer_rx_timestamp(skb)`` is necessary or not - and if it is, don't + call ``netif_rx()`` at all. If ``CONFIG_NETWORK_PHY_TIMESTAMPING`` is + enabled, and ``skb->dev->phydev->mii_ts`` exists, its ``.rxtstamp()`` hook + will be called now, to determine, using logic very similar to DSA, whether + deferral for RX timestamping is necessary. Again like DSA, it becomes the + responsibility of the PHY driver to send the packet up the stack when the + timestamp is available. + + For other skb receive functions, such as ``napi_gro_receive`` and + ``netif_receive_skb``, the stack automatically checks whether + ``skb_defer_rx_timestamp()`` is necessary, so this check is not needed inside + the driver. + +- On TX, again, special intervention might or might not be needed. The + function that calls the ``mii_ts->txtstamp()`` hook is named + ``skb_clone_tx_timestamp()``. This function can either be called directly + (case in which explicit MAC driver support is indeed needed), but the + function also piggybacks from the ``skb_tx_timestamp()`` call, which many MAC + drivers already perform for software timestamping purposes. Therefore, if a + MAC supports software timestamping, it does not need to do anything further + at this stage. + +3.2.3 MII bus snooping devices +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +These perform the same role as timestamping Ethernet PHYs, save for the fact +that they are discrete devices and can therefore be used in conjunction with +any PHY even if it doesn't support timestamping. In Linux, they are +discoverable and attachable to a ``struct phy_device`` through Device Tree, and +for the rest, they use the same mii_ts infrastructure as those. See +Documentation/devicetree/bindings/ptp/timestamper.txt for more details. + +3.2.4 Other caveats for MAC drivers +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Stacked PHCs, especially DSA (but not only) - since that doesn't require any +modification to MAC drivers, so it is more difficult to ensure correctness of +all possible code paths - is that they uncover bugs which were impossible to +trigger before the existence of stacked PTP clocks. One example has to do with +this line of code, already presented earlier:: + + skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS; + +Any TX timestamping logic, be it a plain MAC driver, a DSA switch driver, a PHY +driver or a MII bus snooping device driver, should set this flag. +But a MAC driver that is unaware of PHC stacking might get tripped up by +somebody other than itself setting this flag, and deliver a duplicate +timestamp. +For example, a typical driver design for TX timestamping might be to split the +transmission part into 2 portions: + +1. "TX": checks whether PTP timestamping has been previously enabled through + the ``.ndo_eth_ioctl`` ("``priv->hwtstamp_tx_enabled == true``") and the + current skb requires a TX timestamp ("``skb_shinfo(skb)->tx_flags & + SKBTX_HW_TSTAMP``"). If this is true, it sets the + "``skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS``" flag. Note: as + described above, in the case of a stacked PHC system, this condition should + never trigger, as this MAC is certainly not the outermost PHC. But this is + not where the typical issue is. Transmission proceeds with this packet. + +2. "TX confirmation": Transmission has finished. The driver checks whether it + is necessary to collect any TX timestamp for it. Here is where the typical + issues are: the MAC driver takes a shortcut and only checks whether + "``skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS``" was set. With a stacked + PHC system, this is incorrect because this MAC driver is not the only entity + in the TX data path who could have enabled SKBTX_IN_PROGRESS in the first + place. + +The correct solution for this problem is for MAC drivers to have a compound +check in their "TX confirmation" portion, not only for +"``skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS``", but also for +"``priv->hwtstamp_tx_enabled == true``". Because the rest of the system ensures +that PTP timestamping is not enabled for anything other than the outermost PHC, +this enhanced check will avoid delivering a duplicated TX timestamp to user +space. diff --git a/Documentation/networking/tipc.rst b/Documentation/networking/tipc.rst new file mode 100644 index 0000000000..ab63d298cc --- /dev/null +++ b/Documentation/networking/tipc.rst @@ -0,0 +1,215 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================= +Linux Kernel TIPC +================= + +Introduction +============ + +TIPC (Transparent Inter Process Communication) is a protocol that is specially +designed for intra-cluster communication. It can be configured to transmit +messages either on UDP or directly across Ethernet. Message delivery is +sequence guaranteed, loss free and flow controlled. Latency times are shorter +than with any other known protocol, while maximal throughput is comparable to +that of TCP. + +TIPC Features +------------- + +- Cluster wide IPC service + + Have you ever wished you had the convenience of Unix Domain Sockets even when + transmitting data between cluster nodes? Where you yourself determine the + addresses you want to bind to and use? Where you don't have to perform DNS + lookups and worry about IP addresses? Where you don't have to start timers + to monitor the continuous existence of peer sockets? And yet without the + downsides of that socket type, such as the risk of lingering inodes? + + Welcome to the Transparent Inter Process Communication service, TIPC in short, + which gives you all of this, and a lot more. + +- Service Addressing + + A fundamental concept in TIPC is that of Service Addressing which makes it + possible for a programmer to chose his own address, bind it to a server + socket and let client programs use only that address for sending messages. + +- Service Tracking + + A client wanting to wait for the availability of a server, uses the Service + Tracking mechanism to subscribe for binding and unbinding/close events for + sockets with the associated service address. + + The service tracking mechanism can also be used for Cluster Topology Tracking, + i.e., subscribing for availability/non-availability of cluster nodes. + + Likewise, the service tracking mechanism can be used for Cluster Connectivity + Tracking, i.e., subscribing for up/down events for individual links between + cluster nodes. + +- Transmission Modes + + Using a service address, a client can send datagram messages to a server socket. + + Using the same address type, it can establish a connection towards an accepting + server socket. + + It can also use a service address to create and join a Communication Group, + which is the TIPC manifestation of a brokerless message bus. + + Multicast with very good performance and scalability is available both in + datagram mode and in communication group mode. + +- Inter Node Links + + Communication between any two nodes in a cluster is maintained by one or two + Inter Node Links, which both guarantee data traffic integrity and monitor + the peer node's availability. + +- Cluster Scalability + + By applying the Overlapping Ring Monitoring algorithm on the inter node links + it is possible to scale TIPC clusters up to 1000 nodes with a maintained + neighbor failure discovery time of 1-2 seconds. For smaller clusters this + time can be made much shorter. + +- Neighbor Discovery + + Neighbor Node Discovery in the cluster is done by Ethernet broadcast or UDP + multicast, when any of those services are available. If not, configured peer + IP addresses can be used. + +- Configuration + + When running TIPC in single node mode no configuration whatsoever is needed. + When running in cluster mode TIPC must as a minimum be given a node address + (before Linux 4.17) and told which interface to attach to. The "tipc" + configuration tool makes is possible to add and maintain many more + configuration parameters. + +- Performance + + TIPC message transfer latency times are better than in any other known protocol. + Maximal byte throughput for inter-node connections is still somewhat lower than + for TCP, while they are superior for intra-node and inter-container throughput + on the same host. + +- Language Support + + The TIPC user API has support for C, Python, Perl, Ruby, D and Go. + +More Information +---------------- + +- How to set up TIPC: + + http://tipc.io/getting_started.html + +- How to program with TIPC: + + http://tipc.io/programming.html + +- How to contribute to TIPC: + +- http://tipc.io/contacts.html + +- More details about TIPC specification: + + http://tipc.io/protocol.html + + +Implementation +============== + +TIPC is implemented as a kernel module in net/tipc/ directory. + +TIPC Base Types +--------------- + +.. kernel-doc:: net/tipc/subscr.h + :internal: + +.. kernel-doc:: net/tipc/bearer.h + :internal: + +.. kernel-doc:: net/tipc/name_table.h + :internal: + +.. kernel-doc:: net/tipc/name_distr.h + :internal: + +.. kernel-doc:: net/tipc/bcast.c + :internal: + +TIPC Bearer Interfaces +---------------------- + +.. kernel-doc:: net/tipc/bearer.c + :internal: + +.. kernel-doc:: net/tipc/udp_media.c + :internal: + +TIPC Crypto Interfaces +---------------------- + +.. kernel-doc:: net/tipc/crypto.c + :internal: + +TIPC Discoverer Interfaces +-------------------------- + +.. kernel-doc:: net/tipc/discover.c + :internal: + +TIPC Link Interfaces +-------------------- + +.. kernel-doc:: net/tipc/link.c + :internal: + +TIPC msg Interfaces +------------------- + +.. kernel-doc:: net/tipc/msg.c + :internal: + +TIPC Name Interfaces +-------------------- + +.. kernel-doc:: net/tipc/name_table.c + :internal: + +.. kernel-doc:: net/tipc/name_distr.c + :internal: + +TIPC Node Management Interfaces +------------------------------- + +.. kernel-doc:: net/tipc/node.c + :internal: + +TIPC Socket Interfaces +---------------------- + +.. kernel-doc:: net/tipc/socket.c + :internal: + +TIPC Network Topology Interfaces +-------------------------------- + +.. kernel-doc:: net/tipc/subscr.c + :internal: + +TIPC Server Interfaces +---------------------- + +.. kernel-doc:: net/tipc/topsrv.c + :internal: + +TIPC Trace Interfaces +--------------------- + +.. kernel-doc:: net/tipc/trace.c + :internal: diff --git a/Documentation/networking/tls-handshake.rst b/Documentation/networking/tls-handshake.rst new file mode 100644 index 0000000000..6f5ea1646a --- /dev/null +++ b/Documentation/networking/tls-handshake.rst @@ -0,0 +1,222 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======================= +In-Kernel TLS Handshake +======================= + +Overview +======== + +Transport Layer Security (TLS) is a Upper Layer Protocol (ULP) that runs +over TCP. TLS provides end-to-end data integrity and confidentiality in +addition to peer authentication. + +The kernel's kTLS implementation handles the TLS record subprotocol, but +does not handle the TLS handshake subprotocol which is used to establish +a TLS session. Kernel consumers can use the API described here to +request TLS session establishment. + +There are several possible ways to provide a handshake service in the +kernel. The API described here is designed to hide the details of those +implementations so that in-kernel TLS consumers do not need to be +aware of how the handshake gets done. + + +User handshake agent +==================== + +As of this writing, there is no TLS handshake implementation in the +Linux kernel. To provide a handshake service, a handshake agent +(typically in user space) is started in each network namespace where a +kernel consumer might require a TLS handshake. Handshake agents listen +for events sent from the kernel that indicate a handshake request is +waiting. + +An open socket is passed to a handshake agent via a netlink operation, +which creates a socket descriptor in the agent's file descriptor table. +If the handshake completes successfully, the handshake agent promotes +the socket to use the TLS ULP and sets the session information using the +SOL_TLS socket options. The handshake agent returns the socket to the +kernel via a second netlink operation. + + +Kernel Handshake API +==================== + +A kernel TLS consumer initiates a client-side TLS handshake on an open +socket by invoking one of the tls_client_hello() functions. First, it +fills in a structure that contains the parameters of the request: + +.. code-block:: c + + struct tls_handshake_args { + struct socket *ta_sock; + tls_done_func_t ta_done; + void *ta_data; + const char *ta_peername; + unsigned int ta_timeout_ms; + key_serial_t ta_keyring; + key_serial_t ta_my_cert; + key_serial_t ta_my_privkey; + unsigned int ta_num_peerids; + key_serial_t ta_my_peerids[5]; + }; + +The @ta_sock field references an open and connected socket. The consumer +must hold a reference on the socket to prevent it from being destroyed +while the handshake is in progress. The consumer must also have +instantiated a struct file in sock->file. + + +@ta_done contains a callback function that is invoked when the handshake +has completed. Further explanation of this function is in the "Handshake +Completion" sesction below. + +The consumer can provide a NUL-terminated hostname in the @ta_peername +field that is sent as part of ClientHello. If no peername is provided, +the DNS hostname associated with the server's IP address is used instead. + +The consumer can fill in the @ta_timeout_ms field to force the servicing +handshake agent to exit after a number of milliseconds. This enables the +socket to be fully closed once both the kernel and the handshake agent +have closed their endpoints. + +Authentication material such as x.509 certificates, private certificate +keys, and pre-shared keys are provided to the handshake agent in keys +that are instantiated by the consumer before making the handshake +request. The consumer can provide a private keyring that is linked into +the handshake agent's process keyring in the @ta_keyring field to prevent +access of those keys by other subsystems. + +To request an x.509-authenticated TLS session, the consumer fills in +the @ta_my_cert and @ta_my_privkey fields with the serial numbers of +keys containing an x.509 certificate and the private key for that +certificate. Then, it invokes this function: + +.. code-block:: c + + ret = tls_client_hello_x509(args, gfp_flags); + +The function returns zero when the handshake request is under way. A +zero return guarantees the callback function @ta_done will be invoked +for this socket. The function returns a negative errno if the handshake +could not be started. A negative errno guarantees the callback function +@ta_done will not be invoked on this socket. + + +To initiate a client-side TLS handshake with a pre-shared key, use: + +.. code-block:: c + + ret = tls_client_hello_psk(args, gfp_flags); + +However, in this case, the consumer fills in the @ta_my_peerids array +with serial numbers of keys containing the peer identities it wishes +to offer, and the @ta_num_peerids field with the number of array +entries it has filled in. The other fields are filled in as above. + + +To initiate an anonymous client-side TLS handshake use: + +.. code-block:: c + + ret = tls_client_hello_anon(args, gfp_flags); + +The handshake agent presents no peer identity information to the remote +during this type of handshake. Only server authentication (ie the client +verifies the server's identity) is performed during the handshake. Thus +the established session uses encryption only. + + +Consumers that are in-kernel servers use: + +.. code-block:: c + + ret = tls_server_hello_x509(args, gfp_flags); + +or + +.. code-block:: c + + ret = tls_server_hello_psk(args, gfp_flags); + +The argument structure is filled in as above. + + +If the consumer needs to cancel the handshake request, say, due to a ^C +or other exigent event, the consumer can invoke: + +.. code-block:: c + + bool tls_handshake_cancel(sock); + +This function returns true if the handshake request associated with +@sock has been canceled. The consumer's handshake completion callback +will not be invoked. If this function returns false, then the consumer's +completion callback has already been invoked. + + +Handshake Completion +==================== + +When the handshake agent has completed processing, it notifies the +kernel that the socket may be used by the consumer again. At this point, +the consumer's handshake completion callback, provided in the @ta_done +field in the tls_handshake_args structure, is invoked. + +The synopsis of this function is: + +.. code-block:: c + + typedef void (*tls_done_func_t)(void *data, int status, + key_serial_t peerid); + +The consumer provides a cookie in the @ta_data field of the +tls_handshake_args structure that is returned in the @data parameter of +this callback. The consumer uses the cookie to match the callback to the +thread waiting for the handshake to complete. + +The success status of the handshake is returned via the @status +parameter: + ++------------+----------------------------------------------+ +| status | meaning | ++============+==============================================+ +| 0 | TLS session established successfully | ++------------+----------------------------------------------+ +| -EACCESS | Remote peer rejected the handshake or | +| | authentication failed | ++------------+----------------------------------------------+ +| -ENOMEM | Temporary resource allocation failure | ++------------+----------------------------------------------+ +| -EINVAL | Consumer provided an invalid argument | ++------------+----------------------------------------------+ +| -ENOKEY | Missing authentication material | ++------------+----------------------------------------------+ +| -EIO | An unexpected fault occurred | ++------------+----------------------------------------------+ + +The @peerid parameter contains the serial number of a key containing the +remote peer's identity or the value TLS_NO_PEERID if the session is not +authenticated. + +A best practice is to close and destroy the socket immediately if the +handshake failed. + + +Other considerations +-------------------- + +While a handshake is under way, the kernel consumer must alter the +socket's sk_data_ready callback function to ignore all incoming data. +Once the handshake completion callback function has been invoked, normal +receive operation can be resumed. + +Once a TLS session is established, the consumer must provide a buffer +for and then examine the control message (CMSG) that is part of every +subsequent sock_recvmsg(). Each control message indicates whether the +received message data is TLS record data or session metadata. + +See tls.rst for details on how a kTLS consumer recognizes incoming +(decrypted) application data, alerts, and handshake packets once the +socket has been promoted to use the TLS ULP. diff --git a/Documentation/networking/tls-offload-layers.svg b/Documentation/networking/tls-offload-layers.svg new file mode 100644 index 0000000000..cf72f05dbb --- /dev/null +++ b/Documentation/networking/tls-offload-layers.svg @@ -0,0 +1 @@ +<svg version="1.1" viewBox="0.0 0.0 460.0 500.0" fill="none" stroke="none" stroke-linecap="square" stroke-miterlimit="10" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><clipPath id="p.0"><path d="m0 0l960.0 0l0 720.0l-960.0 0l0 -720.0z" clip-rule="nonzero"/></clipPath><g clip-path="url(#p.0)"><path fill="#000000" fill-opacity="0.0" d="m0 0l960.0 0l0 720.0l-960.0 0z" fill-rule="evenodd"/><path fill="#cfe2f3" d="m117.02887 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SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) + +================== +Kernel TLS offload +================== + +Kernel TLS operation +==================== + +Linux kernel provides TLS connection offload infrastructure. Once a TCP +connection is in ``ESTABLISHED`` state user space can enable the TLS Upper +Layer Protocol (ULP) and install the cryptographic connection state. +For details regarding the user-facing interface refer to the TLS +documentation in :ref:`Documentation/networking/tls.rst <kernel_tls>`. + +``ktls`` can operate in three modes: + + * Software crypto mode (``TLS_SW``) - CPU handles the cryptography. + In most basic cases only crypto operations synchronous with the CPU + can be used, but depending on calling context CPU may utilize + asynchronous crypto accelerators. The use of accelerators introduces extra + latency on socket reads (decryption only starts when a read syscall + is made) and additional I/O load on the system. + * Packet-based NIC offload mode (``TLS_HW``) - the NIC handles crypto + on a packet by packet basis, provided the packets arrive in order. + This mode integrates best with the kernel stack and is described in detail + in the remaining part of this document + (``ethtool`` flags ``tls-hw-tx-offload`` and ``tls-hw-rx-offload``). + * Full TCP NIC offload mode (``TLS_HW_RECORD``) - mode of operation where + NIC driver and firmware replace the kernel networking stack + with its own TCP handling, it is not usable in production environments + making use of the Linux networking stack for example any firewalling + abilities or QoS and packet scheduling (``ethtool`` flag ``tls-hw-record``). + +The operation mode is selected automatically based on device configuration, +offload opt-in or opt-out on per-connection basis is not currently supported. + +TX +-- + +At a high level user write requests are turned into a scatter list, the TLS ULP +intercepts them, inserts record framing, performs encryption (in ``TLS_SW`` +mode) and then hands the modified scatter list to the TCP layer. From this +point on the TCP stack proceeds as normal. + +In ``TLS_HW`` mode the encryption is not performed in the TLS ULP. +Instead packets reach a device driver, the driver will mark the packets +for crypto offload based on the socket the packet is attached to, +and send them to the device for encryption and transmission. + +RX +-- + +On the receive side if the device handled decryption and authentication +successfully, the driver will set the decrypted bit in the associated +:c:type:`struct sk_buff <sk_buff>`. The packets reach the TCP stack and +are handled normally. ``ktls`` is informed when data is queued to the socket +and the ``strparser`` mechanism is used to delineate the records. Upon read +request, records are retrieved from the socket and passed to decryption routine. +If device decrypted all the segments of the record the decryption is skipped, +otherwise software path handles decryption. + +.. kernel-figure:: tls-offload-layers.svg + :alt: TLS offload layers + :align: center + :figwidth: 28em + + Layers of Kernel TLS stack + +Device configuration +==================== + +During driver initialization device sets the ``NETIF_F_HW_TLS_RX`` and +``NETIF_F_HW_TLS_TX`` features and installs its +:c:type:`struct tlsdev_ops <tlsdev_ops>` +pointer in the :c:member:`tlsdev_ops` member of the +:c:type:`struct net_device <net_device>`. + +When TLS cryptographic connection state is installed on a ``ktls`` socket +(note that it is done twice, once for RX and once for TX direction, +and the two are completely independent), the kernel checks if the underlying +network device is offload-capable and attempts the offload. In case offload +fails the connection is handled entirely in software using the same mechanism +as if the offload was never tried. + +Offload request is performed via the :c:member:`tls_dev_add` callback of +:c:type:`struct tlsdev_ops <tlsdev_ops>`: + +.. code-block:: c + + int (*tls_dev_add)(struct net_device *netdev, struct sock *sk, + enum tls_offload_ctx_dir direction, + struct tls_crypto_info *crypto_info, + u32 start_offload_tcp_sn); + +``direction`` indicates whether the cryptographic information is for +the received or transmitted packets. Driver uses the ``sk`` parameter +to retrieve the connection 5-tuple and socket family (IPv4 vs IPv6). +Cryptographic information in ``crypto_info`` includes the key, iv, salt +as well as TLS record sequence number. ``start_offload_tcp_sn`` indicates +which TCP sequence number corresponds to the beginning of the record with +sequence number from ``crypto_info``. The driver can add its state +at the end of kernel structures (see :c:member:`driver_state` members +in ``include/net/tls.h``) to avoid additional allocations and pointer +dereferences. + +TX +-- + +After TX state is installed, the stack guarantees that the first segment +of the stream will start exactly at the ``start_offload_tcp_sn`` sequence +number, simplifying TCP sequence number matching. + +TX offload being fully initialized does not imply that all segments passing +through the driver and which belong to the offloaded socket will be after +the expected sequence number and will have kernel record information. +In particular, already encrypted data may have been queued to the socket +before installing the connection state in the kernel. + +RX +-- + +In RX direction local networking stack has little control over the segmentation, +so the initial records' TCP sequence number may be anywhere inside the segment. + +Normal operation +================ + +At the minimum the device maintains the following state for each connection, in +each direction: + + * crypto secrets (key, iv, salt) + * crypto processing state (partial blocks, partial authentication tag, etc.) + * record metadata (sequence number, processing offset and length) + * expected TCP sequence number + +There are no guarantees on record length or record segmentation. In particular +segments may start at any point of a record and contain any number of records. +Assuming segments are received in order, the device should be able to perform +crypto operations and authentication regardless of segmentation. For this +to be possible device has to keep small amount of segment-to-segment state. +This includes at least: + + * partial headers (if a segment carried only a part of the TLS header) + * partial data block + * partial authentication tag (all data had been seen but part of the + authentication tag has to be written or read from the subsequent segment) + +Record reassembly is not necessary for TLS offload. If the packets arrive +in order the device should be able to handle them separately and make +forward progress. + +TX +-- + +The kernel stack performs record framing reserving space for the authentication +tag and populating all other TLS header and tailer fields. + +Both the device and the driver maintain expected TCP sequence numbers +due to the possibility of retransmissions and the lack of software fallback +once the packet reaches the device. +For segments passed in order, the driver marks the packets with +a connection identifier (note that a 5-tuple lookup is insufficient to identify +packets requiring HW offload, see the :ref:`5tuple_problems` section) +and hands them to the device. The device identifies the packet as requiring +TLS handling and confirms the sequence number matches its expectation. +The device performs encryption and authentication of the record data. +It replaces the authentication tag and TCP checksum with correct values. + +RX +-- + +Before a packet is DMAed to the host (but after NIC's embedded switching +and packet transformation functions) the device validates the Layer 4 +checksum and performs a 5-tuple lookup to find any TLS connection the packet +may belong to (technically a 4-tuple +lookup is sufficient - IP addresses and TCP port numbers, as the protocol +is always TCP). If connection is matched device confirms if the TCP sequence +number is the expected one and proceeds to TLS handling (record delineation, +decryption, authentication for each record in the packet). The device leaves +the record framing unmodified, the stack takes care of record decapsulation. +Device indicates successful handling of TLS offload in the per-packet context +(descriptor) passed to the host. + +Upon reception of a TLS offloaded packet, the driver sets +the :c:member:`decrypted` mark in :c:type:`struct sk_buff <sk_buff>` +corresponding to the segment. Networking stack makes sure decrypted +and non-decrypted segments do not get coalesced (e.g. by GRO or socket layer) +and takes care of partial decryption. + +Resync handling +=============== + +In presence of packet drops or network packet reordering, the device may lose +synchronization with the TLS stream, and require a resync with the kernel's +TCP stack. + +Note that resync is only attempted for connections which were successfully +added to the device table and are in TLS_HW mode. For example, +if the table was full when cryptographic state was installed in the kernel, +such connection will never get offloaded. Therefore the resync request +does not carry any cryptographic connection state. + +TX +-- + +Segments transmitted from an offloaded socket can get out of sync +in similar ways to the receive side-retransmissions - local drops +are possible, though network reorders are not. There are currently +two mechanisms for dealing with out of order segments. + +Crypto state rebuilding +~~~~~~~~~~~~~~~~~~~~~~~ + +Whenever an out of order segment is transmitted the driver provides +the device with enough information to perform cryptographic operations. +This means most likely that the part of the record preceding the current +segment has to be passed to the device as part of the packet context, +together with its TCP sequence number and TLS record number. The device +can then initialize its crypto state, process and discard the preceding +data (to be able to insert the authentication tag) and move onto handling +the actual packet. + +In this mode depending on the implementation the driver can either ask +for a continuation with the crypto state and the new sequence number +(next expected segment is the one after the out of order one), or continue +with the previous stream state - assuming that the out of order segment +was just a retransmission. The former is simpler, and does not require +retransmission detection therefore it is the recommended method until +such time it is proven inefficient. + +Next record sync +~~~~~~~~~~~~~~~~ + +Whenever an out of order segment is detected the driver requests +that the ``ktls`` software fallback code encrypt it. If the segment's +sequence number is lower than expected the driver assumes retransmission +and doesn't change device state. If the segment is in the future, it +may imply a local drop, the driver asks the stack to sync the device +to the next record state and falls back to software. + +Resync request is indicated with: + +.. code-block:: c + + void tls_offload_tx_resync_request(struct sock *sk, u32 got_seq, u32 exp_seq) + +Until resync is complete driver should not access its expected TCP +sequence number (as it will be updated from a different context). +Following helper should be used to test if resync is complete: + +.. code-block:: c + + bool tls_offload_tx_resync_pending(struct sock *sk) + +Next time ``ktls`` pushes a record it will first send its TCP sequence number +and TLS record number to the driver. Stack will also make sure that +the new record will start on a segment boundary (like it does when +the connection is initially added). + +RX +-- + +A small amount of RX reorder events may not require a full resynchronization. +In particular the device should not lose synchronization +when record boundary can be recovered: + +.. kernel-figure:: tls-offload-reorder-good.svg + :alt: reorder of non-header segment + :align: center + + Reorder of non-header segment + +Green segments are successfully decrypted, blue ones are passed +as received on wire, red stripes mark start of new records. + +In above case segment 1 is received and decrypted successfully. +Segment 2 was dropped so 3 arrives out of order. The device knows +the next record starts inside 3, based on record length in segment 1. +Segment 3 is passed untouched, because due to lack of data from segment 2 +the remainder of the previous record inside segment 3 cannot be handled. +The device can, however, collect the authentication algorithm's state +and partial block from the new record in segment 3 and when 4 and 5 +arrive continue decryption. Finally when 2 arrives it's completely outside +of expected window of the device so it's passed as is without special +handling. ``ktls`` software fallback handles the decryption of record +spanning segments 1, 2 and 3. The device did not get out of sync, +even though two segments did not get decrypted. + +Kernel synchronization may be necessary if the lost segment contained +a record header and arrived after the next record header has already passed: + +.. kernel-figure:: tls-offload-reorder-bad.svg + :alt: reorder of header segment + :align: center + + Reorder of segment with a TLS header + +In this example segment 2 gets dropped, and it contains a record header. +Device can only detect that segment 4 also contains a TLS header +if it knows the length of the previous record from segment 2. In this case +the device will lose synchronization with the stream. + +Stream scan resynchronization +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +When the device gets out of sync and the stream reaches TCP sequence +numbers more than a max size record past the expected TCP sequence number, +the device starts scanning for a known header pattern. For example +for TLS 1.2 and TLS 1.3 subsequent bytes of value ``0x03 0x03`` occur +in the SSL/TLS version field of the header. Once pattern is matched +the device continues attempting parsing headers at expected locations +(based on the length fields at guessed locations). +Whenever the expected location does not contain a valid header the scan +is restarted. + +When the header is matched the device sends a confirmation request +to the kernel, asking if the guessed location is correct (if a TLS record +really starts there), and which record sequence number the given header had. +The kernel confirms the guessed location was correct and tells the device +the record sequence number. Meanwhile, the device had been parsing +and counting all records since the just-confirmed one, it adds the number +of records it had seen to the record number provided by the kernel. +At this point the device is in sync and can resume decryption at next +segment boundary. + +In a pathological case the device may latch onto a sequence of matching +headers and never hear back from the kernel (there is no negative +confirmation from the kernel). The implementation may choose to periodically +restart scan. Given how unlikely falsely-matching stream is, however, +periodic restart is not deemed necessary. + +Special care has to be taken if the confirmation request is passed +asynchronously to the packet stream and record may get processed +by the kernel before the confirmation request. + +Stack-driven resynchronization +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The driver may also request the stack to perform resynchronization +whenever it sees the records are no longer getting decrypted. +If the connection is configured in this mode the stack automatically +schedules resynchronization after it has received two completely encrypted +records. + +The stack waits for the socket to drain and informs the device about +the next expected record number and its TCP sequence number. If the +records continue to be received fully encrypted stack retries the +synchronization with an exponential back off (first after 2 encrypted +records, then after 4 records, after 8, after 16... up until every +128 records). + +Error handling +============== + +TX +-- + +Packets may be redirected or rerouted by the stack to a different +device than the selected TLS offload device. The stack will handle +such condition using the :c:func:`sk_validate_xmit_skb` helper +(TLS offload code installs :c:func:`tls_validate_xmit_skb` at this hook). +Offload maintains information about all records until the data is +fully acknowledged, so if skbs reach the wrong device they can be handled +by software fallback. + +Any device TLS offload handling error on the transmission side must result +in the packet being dropped. For example if a packet got out of order +due to a bug in the stack or the device, reached the device and can't +be encrypted such packet must be dropped. + +RX +-- + +If the device encounters any problems with TLS offload on the receive +side it should pass the packet to the host's networking stack as it was +received on the wire. + +For example authentication failure for any record in the segment should +result in passing the unmodified packet to the software fallback. This means +packets should not be modified "in place". Splitting segments to handle partial +decryption is not advised. In other words either all records in the packet +had been handled successfully and authenticated or the packet has to be passed +to the host's stack as it was on the wire (recovering original packet in the +driver if device provides precise error is sufficient). + +The Linux networking stack does not provide a way of reporting per-packet +decryption and authentication errors, packets with errors must simply not +have the :c:member:`decrypted` mark set. + +A packet should also not be handled by the TLS offload if it contains +incorrect checksums. + +Performance metrics +=================== + +TLS offload can be characterized by the following basic metrics: + + * max connection count + * connection installation rate + * connection installation latency + * total cryptographic performance + +Note that each TCP connection requires a TLS session in both directions, +the performance may be reported treating each direction separately. + +Max connection count +-------------------- + +The number of connections device can support can be exposed via +``devlink resource`` API. + +Total cryptographic performance +------------------------------- + +Offload performance may depend on segment and record size. + +Overload of the cryptographic subsystem of the device should not have +significant performance impact on non-offloaded streams. + +Statistics +========== + +Following minimum set of TLS-related statistics should be reported +by the driver: + + * ``rx_tls_decrypted_packets`` - number of successfully decrypted RX packets + which were part of a TLS stream. + * ``rx_tls_decrypted_bytes`` - number of TLS payload bytes in RX packets + which were successfully decrypted. + * ``rx_tls_ctx`` - number of TLS RX HW offload contexts added to device for + decryption. + * ``rx_tls_del`` - number of TLS RX HW offload contexts deleted from device + (connection has finished). + * ``rx_tls_resync_req_pkt`` - number of received TLS packets with a resync + request. + * ``rx_tls_resync_req_start`` - number of times the TLS async resync request + was started. + * ``rx_tls_resync_req_end`` - number of times the TLS async resync request + properly ended with providing the HW tracked tcp-seq. + * ``rx_tls_resync_req_skip`` - number of times the TLS async resync request + procedure was started by not properly ended. + * ``rx_tls_resync_res_ok`` - number of times the TLS resync response call to + the driver was successfully handled. + * ``rx_tls_resync_res_skip`` - number of times the TLS resync response call to + the driver was terminated unsuccessfully. + * ``rx_tls_err`` - number of RX packets which were part of a TLS stream + but were not decrypted due to unexpected error in the state machine. + * ``tx_tls_encrypted_packets`` - number of TX packets passed to the device + for encryption of their TLS payload. + * ``tx_tls_encrypted_bytes`` - number of TLS payload bytes in TX packets + passed to the device for encryption. + * ``tx_tls_ctx`` - number of TLS TX HW offload contexts added to device for + encryption. + * ``tx_tls_ooo`` - number of TX packets which were part of a TLS stream + but did not arrive in the expected order. + * ``tx_tls_skip_no_sync_data`` - number of TX packets which were part of + a TLS stream and arrived out-of-order, but skipped the HW offload routine + and went to the regular transmit flow as they were retransmissions of the + connection handshake. + * ``tx_tls_drop_no_sync_data`` - number of TX packets which were part of + a TLS stream dropped, because they arrived out of order and associated + record could not be found. + * ``tx_tls_drop_bypass_req`` - number of TX packets which were part of a TLS + stream dropped, because they contain both data that has been encrypted by + software and data that expects hardware crypto offload. + +Notable corner cases, exceptions and additional requirements +============================================================ + +.. _5tuple_problems: + +5-tuple matching limitations +---------------------------- + +The device can only recognize received packets based on the 5-tuple +of the socket. Current ``ktls`` implementation will not offload sockets +routed through software interfaces such as those used for tunneling +or virtual networking. However, many packet transformations performed +by the networking stack (most notably any BPF logic) do not require +any intermediate software device, therefore a 5-tuple match may +consistently miss at the device level. In such cases the device +should still be able to perform TX offload (encryption) and should +fallback cleanly to software decryption (RX). + +Out of order +------------ + +Introducing extra processing in NICs should not cause packets to be +transmitted or received out of order, for example pure ACK packets +should not be reordered with respect to data segments. + +Ingress reorder +--------------- + +A device is permitted to perform packet reordering for consecutive +TCP segments (i.e. placing packets in the correct order) but any form +of additional buffering is disallowed. + +Coexistence with standard networking offload features +----------------------------------------------------- + +Offloaded ``ktls`` sockets should support standard TCP stack features +transparently. Enabling device TLS offload should not cause any difference +in packets as seen on the wire. + +Transport layer transparency +---------------------------- + +The device should not modify any packet headers for the purpose +of the simplifying TLS offload. + +The device should not depend on any packet headers beyond what is strictly +necessary for TLS offload. + +Segment drops +------------- + +Dropping packets is acceptable only in the event of catastrophic +system errors and should never be used as an error handling mechanism +in cases arising from normal operation. In other words, reliance +on TCP retransmissions to handle corner cases is not acceptable. + +TLS device features +------------------- + +Drivers should ignore the changes to the TLS device feature flags. +These flags will be acted upon accordingly by the core ``ktls`` code. +TLS device feature flags only control adding of new TLS connection +offloads, old connections will remain active after flags are cleared. + +TLS encryption cannot be offloaded to devices without checksum calculation +offload. Hence, TLS TX device feature flag requires TX csum offload being set. +Disabling the latter implies clearing the former. Disabling TX checksum offload +should not affect old connections, and drivers should make sure checksum +calculation does not break for them. +Similarly, device-offloaded TLS decryption implies doing RXCSUM. If the user +does not want to enable RX csum offload, TLS RX device feature is disabled +as well. diff --git a/Documentation/networking/tls.rst b/Documentation/networking/tls.rst new file mode 100644 index 0000000000..658ed3a71e --- /dev/null +++ b/Documentation/networking/tls.rst @@ -0,0 +1,288 @@ +.. _kernel_tls: + +========== +Kernel TLS +========== + +Overview +======== + +Transport Layer Security (TLS) is a Upper Layer Protocol (ULP) that runs over +TCP. TLS provides end-to-end data integrity and confidentiality. + +User interface +============== + +Creating a TLS connection +------------------------- + +First create a new TCP socket and set the TLS ULP. + +.. code-block:: c + + sock = socket(AF_INET, SOCK_STREAM, 0); + setsockopt(sock, SOL_TCP, TCP_ULP, "tls", sizeof("tls")); + +Setting the TLS ULP allows us to set/get TLS socket options. Currently +only the symmetric encryption is handled in the kernel. After the TLS +handshake is complete, we have all the parameters required to move the +data-path to the kernel. There is a separate socket option for moving +the transmit and the receive into the kernel. + +.. code-block:: c + + /* From linux/tls.h */ + struct tls_crypto_info { + unsigned short version; + unsigned short cipher_type; + }; + + struct tls12_crypto_info_aes_gcm_128 { + struct tls_crypto_info info; + unsigned char iv[TLS_CIPHER_AES_GCM_128_IV_SIZE]; + unsigned char key[TLS_CIPHER_AES_GCM_128_KEY_SIZE]; + unsigned char salt[TLS_CIPHER_AES_GCM_128_SALT_SIZE]; + unsigned char rec_seq[TLS_CIPHER_AES_GCM_128_REC_SEQ_SIZE]; + }; + + + struct tls12_crypto_info_aes_gcm_128 crypto_info; + + crypto_info.info.version = TLS_1_2_VERSION; + crypto_info.info.cipher_type = TLS_CIPHER_AES_GCM_128; + memcpy(crypto_info.iv, iv_write, TLS_CIPHER_AES_GCM_128_IV_SIZE); + memcpy(crypto_info.rec_seq, seq_number_write, + TLS_CIPHER_AES_GCM_128_REC_SEQ_SIZE); + memcpy(crypto_info.key, cipher_key_write, TLS_CIPHER_AES_GCM_128_KEY_SIZE); + memcpy(crypto_info.salt, implicit_iv_write, TLS_CIPHER_AES_GCM_128_SALT_SIZE); + + setsockopt(sock, SOL_TLS, TLS_TX, &crypto_info, sizeof(crypto_info)); + +Transmit and receive are set separately, but the setup is the same, using either +TLS_TX or TLS_RX. + +Sending TLS application data +---------------------------- + +After setting the TLS_TX socket option all application data sent over this +socket is encrypted using TLS and the parameters provided in the socket option. +For example, we can send an encrypted hello world record as follows: + +.. code-block:: c + + const char *msg = "hello world\n"; + send(sock, msg, strlen(msg)); + +send() data is directly encrypted from the userspace buffer provided +to the encrypted kernel send buffer if possible. + +The sendfile system call will send the file's data over TLS records of maximum +length (2^14). + +.. code-block:: c + + file = open(filename, O_RDONLY); + fstat(file, &stat); + sendfile(sock, file, &offset, stat.st_size); + +TLS records are created and sent after each send() call, unless +MSG_MORE is passed. MSG_MORE will delay creation of a record until +MSG_MORE is not passed, or the maximum record size is reached. + +The kernel will need to allocate a buffer for the encrypted data. +This buffer is allocated at the time send() is called, such that +either the entire send() call will return -ENOMEM (or block waiting +for memory), or the encryption will always succeed. If send() returns +-ENOMEM and some data was left on the socket buffer from a previous +call using MSG_MORE, the MSG_MORE data is left on the socket buffer. + +Receiving TLS application data +------------------------------ + +After setting the TLS_RX socket option, all recv family socket calls +are decrypted using TLS parameters provided. A full TLS record must +be received before decryption can happen. + +.. code-block:: c + + char buffer[16384]; + recv(sock, buffer, 16384); + +Received data is decrypted directly in to the user buffer if it is +large enough, and no additional allocations occur. If the userspace +buffer is too small, data is decrypted in the kernel and copied to +userspace. + +``EINVAL`` is returned if the TLS version in the received message does not +match the version passed in setsockopt. + +``EMSGSIZE`` is returned if the received message is too big. + +``EBADMSG`` is returned if decryption failed for any other reason. + +Send TLS control messages +------------------------- + +Other than application data, TLS has control messages such as alert +messages (record type 21) and handshake messages (record type 22), etc. +These messages can be sent over the socket by providing the TLS record type +via a CMSG. For example the following function sends @data of @length bytes +using a record of type @record_type. + +.. code-block:: c + + /* send TLS control message using record_type */ + static int klts_send_ctrl_message(int sock, unsigned char record_type, + void *data, size_t length) + { + struct msghdr msg = {0}; + int cmsg_len = sizeof(record_type); + struct cmsghdr *cmsg; + char buf[CMSG_SPACE(cmsg_len)]; + struct iovec msg_iov; /* Vector of data to send/receive into. */ + + msg.msg_control = buf; + msg.msg_controllen = sizeof(buf); + cmsg = CMSG_FIRSTHDR(&msg); + cmsg->cmsg_level = SOL_TLS; + cmsg->cmsg_type = TLS_SET_RECORD_TYPE; + cmsg->cmsg_len = CMSG_LEN(cmsg_len); + *CMSG_DATA(cmsg) = record_type; + msg.msg_controllen = cmsg->cmsg_len; + + msg_iov.iov_base = data; + msg_iov.iov_len = length; + msg.msg_iov = &msg_iov; + msg.msg_iovlen = 1; + + return sendmsg(sock, &msg, 0); + } + +Control message data should be provided unencrypted, and will be +encrypted by the kernel. + +Receiving TLS control messages +------------------------------ + +TLS control messages are passed in the userspace buffer, with message +type passed via cmsg. If no cmsg buffer is provided, an error is +returned if a control message is received. Data messages may be +received without a cmsg buffer set. + +.. code-block:: c + + char buffer[16384]; + char cmsg[CMSG_SPACE(sizeof(unsigned char))]; + struct msghdr msg = {0}; + msg.msg_control = cmsg; + msg.msg_controllen = sizeof(cmsg); + + struct iovec msg_iov; + msg_iov.iov_base = buffer; + msg_iov.iov_len = 16384; + + msg.msg_iov = &msg_iov; + msg.msg_iovlen = 1; + + int ret = recvmsg(sock, &msg, 0 /* flags */); + + struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg); + if (cmsg->cmsg_level == SOL_TLS && + cmsg->cmsg_type == TLS_GET_RECORD_TYPE) { + int record_type = *((unsigned char *)CMSG_DATA(cmsg)); + // Do something with record_type, and control message data in + // buffer. + // + // Note that record_type may be == to application data (23). + } else { + // Buffer contains application data. + } + +recv will never return data from mixed types of TLS records. + +Integrating in to userspace TLS library +--------------------------------------- + +At a high level, the kernel TLS ULP is a replacement for the record +layer of a userspace TLS library. + +A patchset to OpenSSL to use ktls as the record layer is +`here <https://github.com/Mellanox/openssl/commits/tls_rx2>`_. + +`An example <https://github.com/ktls/af_ktls-tool/commits/RX>`_ +of calling send directly after a handshake using gnutls. +Since it doesn't implement a full record layer, control +messages are not supported. + +Optional optimizations +---------------------- + +There are certain condition-specific optimizations the TLS ULP can make, +if requested. Those optimizations are either not universally beneficial +or may impact correctness, hence they require an opt-in. +All options are set per-socket using setsockopt(), and their +state can be checked using getsockopt() and via socket diag (``ss``). + +TLS_TX_ZEROCOPY_RO +~~~~~~~~~~~~~~~~~~ + +For device offload only. Allow sendfile() data to be transmitted directly +to the NIC without making an in-kernel copy. This allows true zero-copy +behavior when device offload is enabled. + +The application must make sure that the data is not modified between being +submitted and transmission completing. In other words this is mostly +applicable if the data sent on a socket via sendfile() is read-only. + +Modifying the data may result in different versions of the data being used +for the original TCP transmission and TCP retransmissions. To the receiver +this will look like TLS records had been tampered with and will result +in record authentication failures. + +TLS_RX_EXPECT_NO_PAD +~~~~~~~~~~~~~~~~~~~~ + +TLS 1.3 only. Expect the sender to not pad records. This allows the data +to be decrypted directly into user space buffers with TLS 1.3. + +This optimization is safe to enable only if the remote end is trusted, +otherwise it is an attack vector to doubling the TLS processing cost. + +If the record decrypted turns out to had been padded or is not a data +record it will be decrypted again into a kernel buffer without zero copy. +Such events are counted in the ``TlsDecryptRetry`` statistic. + +Statistics +========== + +TLS implementation exposes the following per-namespace statistics +(``/proc/net/tls_stat``): + +- ``TlsCurrTxSw``, ``TlsCurrRxSw`` - + number of TX and RX sessions currently installed where host handles + cryptography + +- ``TlsCurrTxDevice``, ``TlsCurrRxDevice`` - + number of TX and RX sessions currently installed where NIC handles + cryptography + +- ``TlsTxSw``, ``TlsRxSw`` - + number of TX and RX sessions opened with host cryptography + +- ``TlsTxDevice``, ``TlsRxDevice`` - + number of TX and RX sessions opened with NIC cryptography + +- ``TlsDecryptError`` - + record decryption failed (e.g. due to incorrect authentication tag) + +- ``TlsDeviceRxResync`` - + number of RX resyncs sent to NICs handling cryptography + +- ``TlsDecryptRetry`` - + number of RX records which had to be re-decrypted due to + ``TLS_RX_EXPECT_NO_PAD`` mis-prediction. Note that this counter will + also increment for non-data records. + +- ``TlsRxNoPadViolation`` - + number of data RX records which had to be re-decrypted due to + ``TLS_RX_EXPECT_NO_PAD`` mis-prediction. diff --git a/Documentation/networking/tproxy.rst b/Documentation/networking/tproxy.rst new file mode 100644 index 0000000000..00dc3a1a66 --- /dev/null +++ b/Documentation/networking/tproxy.rst @@ -0,0 +1,109 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================= +Transparent proxy support +========================= + +This feature adds Linux 2.2-like transparent proxy support to current kernels. +To use it, enable the socket match and the TPROXY target in your kernel config. +You will need policy routing too, so be sure to enable that as well. + +From Linux 4.18 transparent proxy support is also available in nf_tables. + +1. Making non-local sockets work +================================ + +The idea is that you identify packets with destination address matching a local +socket on your box, set the packet mark to a certain value:: + + # iptables -t mangle -N DIVERT + # iptables -t mangle -A PREROUTING -p tcp -m socket -j DIVERT + # iptables -t mangle -A DIVERT -j MARK --set-mark 1 + # iptables -t mangle -A DIVERT -j ACCEPT + +Alternatively you can do this in nft with the following commands:: + + # nft add table filter + # nft add chain filter divert "{ type filter hook prerouting priority -150; }" + # nft add rule filter divert meta l4proto tcp socket transparent 1 meta mark set 1 accept + +And then match on that value using policy routing to have those packets +delivered locally:: + + # ip rule add fwmark 1 lookup 100 + # ip route add local 0.0.0.0/0 dev lo table 100 + +Because of certain restrictions in the IPv4 routing output code you'll have to +modify your application to allow it to send datagrams _from_ non-local IP +addresses. All you have to do is enable the (SOL_IP, IP_TRANSPARENT) socket +option before calling bind:: + + fd = socket(AF_INET, SOCK_STREAM, 0); + /* - 8< -*/ + int value = 1; + setsockopt(fd, SOL_IP, IP_TRANSPARENT, &value, sizeof(value)); + /* - 8< -*/ + name.sin_family = AF_INET; + name.sin_port = htons(0xCAFE); + name.sin_addr.s_addr = htonl(0xDEADBEEF); + bind(fd, &name, sizeof(name)); + +A trivial patch for netcat is available here: +http://people.netfilter.org/hidden/tproxy/netcat-ip_transparent-support.patch + + +2. Redirecting traffic +====================== + +Transparent proxying often involves "intercepting" traffic on a router. This is +usually done with the iptables REDIRECT target; however, there are serious +limitations of that method. One of the major issues is that it actually +modifies the packets to change the destination address -- which might not be +acceptable in certain situations. (Think of proxying UDP for example: you won't +be able to find out the original destination address. Even in case of TCP +getting the original destination address is racy.) + +The 'TPROXY' target provides similar functionality without relying on NAT. Simply +add rules like this to the iptables ruleset above:: + + # iptables -t mangle -A PREROUTING -p tcp --dport 80 -j TPROXY \ + --tproxy-mark 0x1/0x1 --on-port 50080 + +Or the following rule to nft: + +# nft add rule filter divert tcp dport 80 tproxy to :50080 meta mark set 1 accept + +Note that for this to work you'll have to modify the proxy to enable (SOL_IP, +IP_TRANSPARENT) for the listening socket. + +As an example implementation, tcprdr is available here: +https://git.breakpoint.cc/cgit/fw/tcprdr.git/ +This tool is written by Florian Westphal and it was used for testing during the +nf_tables implementation. + +3. Iptables and nf_tables extensions +==================================== + +To use tproxy you'll need to have the following modules compiled for iptables: + + - NETFILTER_XT_MATCH_SOCKET + - NETFILTER_XT_TARGET_TPROXY + +Or the floowing modules for nf_tables: + + - NFT_SOCKET + - NFT_TPROXY + +4. Application support +====================== + +4.1. Squid +---------- + +Squid 3.HEAD has support built-in. To use it, pass +'--enable-linux-netfilter' to configure and set the 'tproxy' option on +the HTTP listener you redirect traffic to with the TPROXY iptables +target. + +For more information please consult the following page on the Squid +wiki: http://wiki.squid-cache.org/Features/Tproxy4 diff --git a/Documentation/networking/tuntap.rst b/Documentation/networking/tuntap.rst new file mode 100644 index 0000000000..4d7087f727 --- /dev/null +++ b/Documentation/networking/tuntap.rst @@ -0,0 +1,259 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> + +=============================== +Universal TUN/TAP device driver +=============================== + +Copyright |copy| 1999-2000 Maxim Krasnyansky <max_mk@yahoo.com> + + Linux, Solaris drivers + Copyright |copy| 1999-2000 Maxim Krasnyansky <max_mk@yahoo.com> + + FreeBSD TAP driver + Copyright |copy| 1999-2000 Maksim Yevmenkin <m_evmenkin@yahoo.com> + + Revision of this document 2002 by Florian Thiel <florian.thiel@gmx.net> + +1. Description +============== + + TUN/TAP provides packet reception and transmission for user space programs. + It can be seen as a simple Point-to-Point or Ethernet device, which, + instead of receiving packets from physical media, receives them from + user space program and instead of sending packets via physical media + writes them to the user space program. + + In order to use the driver a program has to open /dev/net/tun and issue a + corresponding ioctl() to register a network device with the kernel. A network + device will appear as tunXX or tapXX, depending on the options chosen. When + the program closes the file descriptor, the network device and all + corresponding routes will disappear. + + Depending on the type of device chosen the userspace program has to read/write + IP packets (with tun) or ethernet frames (with tap). Which one is being used + depends on the flags given with the ioctl(). + + The package from http://vtun.sourceforge.net/tun contains two simple examples + for how to use tun and tap devices. Both programs work like a bridge between + two network interfaces. + br_select.c - bridge based on select system call. + br_sigio.c - bridge based on async io and SIGIO signal. + However, the best example is VTun http://vtun.sourceforge.net :)) + +2. Configuration +================ + + Create device node:: + + mkdir /dev/net (if it doesn't exist already) + mknod /dev/net/tun c 10 200 + + Set permissions:: + + e.g. chmod 0666 /dev/net/tun + + There's no harm in allowing the device to be accessible by non-root users, + since CAP_NET_ADMIN is required for creating network devices or for + connecting to network devices which aren't owned by the user in question. + If you want to create persistent devices and give ownership of them to + unprivileged users, then you need the /dev/net/tun device to be usable by + those users. + + Driver module autoloading + + Make sure that "Kernel module loader" - module auto-loading + support is enabled in your kernel. The kernel should load it on + first access. + + Manual loading + + insert the module by hand:: + + modprobe tun + + If you do it the latter way, you have to load the module every time you + need it, if you do it the other way it will be automatically loaded when + /dev/net/tun is being opened. + +3. Program interface +==================== + +3.1 Network device allocation +----------------------------- + +``char *dev`` should be the name of the device with a format string (e.g. +"tun%d"), but (as far as I can see) this can be any valid network device name. +Note that the character pointer becomes overwritten with the real device name +(e.g. "tun0"):: + + #include <linux/if.h> + #include <linux/if_tun.h> + + int tun_alloc(char *dev) + { + struct ifreq ifr; + int fd, err; + + if( (fd = open("/dev/net/tun", O_RDWR)) < 0 ) + return tun_alloc_old(dev); + + memset(&ifr, 0, sizeof(ifr)); + + /* Flags: IFF_TUN - TUN device (no Ethernet headers) + * IFF_TAP - TAP device + * + * IFF_NO_PI - Do not provide packet information + */ + ifr.ifr_flags = IFF_TUN; + if( *dev ) + strscpy_pad(ifr.ifr_name, dev, IFNAMSIZ); + + if( (err = ioctl(fd, TUNSETIFF, (void *) &ifr)) < 0 ){ + close(fd); + return err; + } + strcpy(dev, ifr.ifr_name); + return fd; + } + +3.2 Frame format +---------------- + +If flag IFF_NO_PI is not set each frame format is:: + + Flags [2 bytes] + Proto [2 bytes] + Raw protocol(IP, IPv6, etc) frame. + +3.3 Multiqueue tuntap interface +------------------------------- + +From version 3.8, Linux supports multiqueue tuntap which can uses multiple +file descriptors (queues) to parallelize packets sending or receiving. The +device allocation is the same as before, and if user wants to create multiple +queues, TUNSETIFF with the same device name must be called many times with +IFF_MULTI_QUEUE flag. + +``char *dev`` should be the name of the device, queues is the number of queues +to be created, fds is used to store and return the file descriptors (queues) +created to the caller. Each file descriptor were served as the interface of a +queue which could be accessed by userspace. + +:: + + #include <linux/if.h> + #include <linux/if_tun.h> + + int tun_alloc_mq(char *dev, int queues, int *fds) + { + struct ifreq ifr; + int fd, err, i; + + if (!dev) + return -1; + + memset(&ifr, 0, sizeof(ifr)); + /* Flags: IFF_TUN - TUN device (no Ethernet headers) + * IFF_TAP - TAP device + * + * IFF_NO_PI - Do not provide packet information + * IFF_MULTI_QUEUE - Create a queue of multiqueue device + */ + ifr.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_MULTI_QUEUE; + strcpy(ifr.ifr_name, dev); + + for (i = 0; i < queues; i++) { + if ((fd = open("/dev/net/tun", O_RDWR)) < 0) + goto err; + err = ioctl(fd, TUNSETIFF, (void *)&ifr); + if (err) { + close(fd); + goto err; + } + fds[i] = fd; + } + + return 0; + err: + for (--i; i >= 0; i--) + close(fds[i]); + return err; + } + +A new ioctl(TUNSETQUEUE) were introduced to enable or disable a queue. When +calling it with IFF_DETACH_QUEUE flag, the queue were disabled. And when +calling it with IFF_ATTACH_QUEUE flag, the queue were enabled. The queue were +enabled by default after it was created through TUNSETIFF. + +fd is the file descriptor (queue) that we want to enable or disable, when +enable is true we enable it, otherwise we disable it:: + + #include <linux/if.h> + #include <linux/if_tun.h> + + int tun_set_queue(int fd, int enable) + { + struct ifreq ifr; + + memset(&ifr, 0, sizeof(ifr)); + + if (enable) + ifr.ifr_flags = IFF_ATTACH_QUEUE; + else + ifr.ifr_flags = IFF_DETACH_QUEUE; + + return ioctl(fd, TUNSETQUEUE, (void *)&ifr); + } + +Universal TUN/TAP device driver Frequently Asked Question +========================================================= + +1. What platforms are supported by TUN/TAP driver ? + +Currently driver has been written for 3 Unices: + + - Linux kernels 2.2.x, 2.4.x + - FreeBSD 3.x, 4.x, 5.x + - Solaris 2.6, 7.0, 8.0 + +2. What is TUN/TAP driver used for? + +As mentioned above, main purpose of TUN/TAP driver is tunneling. +It is used by VTun (http://vtun.sourceforge.net). + +Another interesting application using TUN/TAP is pipsecd +(http://perso.enst.fr/~beyssac/pipsec/), a userspace IPSec +implementation that can use complete kernel routing (unlike FreeS/WAN). + +3. How does Virtual network device actually work ? + +Virtual network device can be viewed as a simple Point-to-Point or +Ethernet device, which instead of receiving packets from a physical +media, receives them from user space program and instead of sending +packets via physical media sends them to the user space program. + +Let's say that you configured IPv6 on the tap0, then whenever +the kernel sends an IPv6 packet to tap0, it is passed to the application +(VTun for example). The application encrypts, compresses and sends it to +the other side over TCP or UDP. The application on the other side decompresses +and decrypts the data received and writes the packet to the TAP device, +the kernel handles the packet like it came from real physical device. + +4. What is the difference between TUN driver and TAP driver? + +TUN works with IP frames. TAP works with Ethernet frames. + +This means that you have to read/write IP packets when you are using tun and +ethernet frames when using tap. + +5. What is the difference between BPF and TUN/TAP driver? + +BPF is an advanced packet filter. It can be attached to existing +network interface. It does not provide a virtual network interface. +A TUN/TAP driver does provide a virtual network interface and it is possible +to attach BPF to this interface. + +6. Does TAP driver support kernel Ethernet bridging? + +Yes. Linux and FreeBSD drivers support Ethernet bridging. diff --git a/Documentation/networking/udplite.rst b/Documentation/networking/udplite.rst new file mode 100644 index 0000000000..2c225f28b7 --- /dev/null +++ b/Documentation/networking/udplite.rst @@ -0,0 +1,291 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================================ +The UDP-Lite protocol (RFC 3828) +================================ + + + UDP-Lite is a Standards-Track IETF transport protocol whose characteristic + is a variable-length checksum. This has advantages for transport of multimedia + (video, VoIP) over wireless networks, as partly damaged packets can still be + fed into the codec instead of being discarded due to a failed checksum test. + + This file briefly describes the existing kernel support and the socket API. + For in-depth information, you can consult: + + - The UDP-Lite Homepage: + http://web.archive.org/web/%2E/http://www.erg.abdn.ac.uk/users/gerrit/udp-lite/ + + From here you can also download some example application source code. + + - The UDP-Lite HOWTO on + http://web.archive.org/web/%2E/http://www.erg.abdn.ac.uk/users/gerrit/udp-lite/files/UDP-Lite-HOWTO.txt + + - The Wireshark UDP-Lite WiKi (with capture files): + https://wiki.wireshark.org/Lightweight_User_Datagram_Protocol + + - The Protocol Spec, RFC 3828, http://www.ietf.org/rfc/rfc3828.txt + + +1. Applications +=============== + + Several applications have been ported successfully to UDP-Lite. Ethereal + (now called wireshark) has UDP-Litev4/v6 support by default. + + Porting applications to UDP-Lite is straightforward: only socket level and + IPPROTO need to be changed; senders additionally set the checksum coverage + length (default = header length = 8). Details are in the next section. + +2. Programming API +================== + + UDP-Lite provides a connectionless, unreliable datagram service and hence + uses the same socket type as UDP. In fact, porting from UDP to UDP-Lite is + very easy: simply add ``IPPROTO_UDPLITE`` as the last argument of the + socket(2) call so that the statement looks like:: + + s = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDPLITE); + + or, respectively, + + :: + + s = socket(PF_INET6, SOCK_DGRAM, IPPROTO_UDPLITE); + + With just the above change you are able to run UDP-Lite services or connect + to UDP-Lite servers. The kernel will assume that you are not interested in + using partial checksum coverage and so emulate UDP mode (full coverage). + + To make use of the partial checksum coverage facilities requires setting a + single socket option, which takes an integer specifying the coverage length: + + * Sender checksum coverage: UDPLITE_SEND_CSCOV + + For example:: + + int val = 20; + setsockopt(s, SOL_UDPLITE, UDPLITE_SEND_CSCOV, &val, sizeof(int)); + + sets the checksum coverage length to 20 bytes (12b data + 8b header). + Of each packet only the first 20 bytes (plus the pseudo-header) will be + checksummed. This is useful for RTP applications which have a 12-byte + base header. + + + * Receiver checksum coverage: UDPLITE_RECV_CSCOV + + This option is the receiver-side analogue. It is truly optional, i.e. not + required to enable traffic with partial checksum coverage. Its function is + that of a traffic filter: when enabled, it instructs the kernel to drop + all packets which have a coverage _less_ than this value. For example, if + RTP and UDP headers are to be protected, a receiver can enforce that only + packets with a minimum coverage of 20 are admitted:: + + int min = 20; + setsockopt(s, SOL_UDPLITE, UDPLITE_RECV_CSCOV, &min, sizeof(int)); + + The calls to getsockopt(2) are analogous. Being an extension and not a stand- + alone protocol, all socket options known from UDP can be used in exactly the + same manner as before, e.g. UDP_CORK or UDP_ENCAP. + + A detailed discussion of UDP-Lite checksum coverage options is in section IV. + +3. Header Files +=============== + + The socket API requires support through header files in /usr/include: + + * /usr/include/netinet/in.h + to define IPPROTO_UDPLITE + + * /usr/include/netinet/udplite.h + for UDP-Lite header fields and protocol constants + + For testing purposes, the following can serve as a ``mini`` header file:: + + #define IPPROTO_UDPLITE 136 + #define SOL_UDPLITE 136 + #define UDPLITE_SEND_CSCOV 10 + #define UDPLITE_RECV_CSCOV 11 + + Ready-made header files for various distros are in the UDP-Lite tarball. + +4. Kernel Behaviour with Regards to the Various Socket Options +============================================================== + + + To enable debugging messages, the log level need to be set to 8, as most + messages use the KERN_DEBUG level (7). + + 1) Sender Socket Options + + If the sender specifies a value of 0 as coverage length, the module + assumes full coverage, transmits a packet with coverage length of 0 + and according checksum. If the sender specifies a coverage < 8 and + different from 0, the kernel assumes 8 as default value. Finally, + if the specified coverage length exceeds the packet length, the packet + length is used instead as coverage length. + + 2) Receiver Socket Options + + The receiver specifies the minimum value of the coverage length it + is willing to accept. A value of 0 here indicates that the receiver + always wants the whole of the packet covered. In this case, all + partially covered packets are dropped and an error is logged. + + It is not possible to specify illegal values (<0 and <8); in these + cases the default of 8 is assumed. + + All packets arriving with a coverage value less than the specified + threshold are discarded, these events are also logged. + + 3) Disabling the Checksum Computation + + On both sender and receiver, checksumming will always be performed + and cannot be disabled using SO_NO_CHECK. Thus:: + + setsockopt(sockfd, SOL_SOCKET, SO_NO_CHECK, ... ); + + will always will be ignored, while the value of:: + + getsockopt(sockfd, SOL_SOCKET, SO_NO_CHECK, &value, ...); + + is meaningless (as in TCP). Packets with a zero checksum field are + illegal (cf. RFC 3828, sec. 3.1) and will be silently discarded. + + 4) Fragmentation + + The checksum computation respects both buffersize and MTU. The size + of UDP-Lite packets is determined by the size of the send buffer. The + minimum size of the send buffer is 2048 (defined as SOCK_MIN_SNDBUF + in include/net/sock.h), the default value is configurable as + net.core.wmem_default or via setting the SO_SNDBUF socket(7) + option. The maximum upper bound for the send buffer is determined + by net.core.wmem_max. + + Given a payload size larger than the send buffer size, UDP-Lite will + split the payload into several individual packets, filling up the + send buffer size in each case. + + The precise value also depends on the interface MTU. The interface MTU, + in turn, may trigger IP fragmentation. In this case, the generated + UDP-Lite packet is split into several IP packets, of which only the + first one contains the L4 header. + + The send buffer size has implications on the checksum coverage length. + Consider the following example:: + + Payload: 1536 bytes Send Buffer: 1024 bytes + MTU: 1500 bytes Coverage Length: 856 bytes + + UDP-Lite will ship the 1536 bytes in two separate packets:: + + Packet 1: 1024 payload + 8 byte header + 20 byte IP header = 1052 bytes + Packet 2: 512 payload + 8 byte header + 20 byte IP header = 540 bytes + + The coverage packet covers the UDP-Lite header and 848 bytes of the + payload in the first packet, the second packet is fully covered. Note + that for the second packet, the coverage length exceeds the packet + length. The kernel always re-adjusts the coverage length to the packet + length in such cases. + + As an example of what happens when one UDP-Lite packet is split into + several tiny fragments, consider the following example:: + + Payload: 1024 bytes Send buffer size: 1024 bytes + MTU: 300 bytes Coverage length: 575 bytes + + +-+-----------+--------------+--------------+--------------+ + |8| 272 | 280 | 280 | 280 | + +-+-----------+--------------+--------------+--------------+ + 280 560 840 1032 + ^ + *****checksum coverage************* + + The UDP-Lite module generates one 1032 byte packet (1024 + 8 byte + header). According to the interface MTU, these are split into 4 IP + packets (280 byte IP payload + 20 byte IP header). The kernel module + sums the contents of the entire first two packets, plus 15 bytes of + the last packet before releasing the fragments to the IP module. + + To see the analogous case for IPv6 fragmentation, consider a link + MTU of 1280 bytes and a write buffer of 3356 bytes. If the checksum + coverage is less than 1232 bytes (MTU minus IPv6/fragment header + lengths), only the first fragment needs to be considered. When using + larger checksum coverage lengths, each eligible fragment needs to be + checksummed. Suppose we have a checksum coverage of 3062. The buffer + of 3356 bytes will be split into the following fragments:: + + Fragment 1: 1280 bytes carrying 1232 bytes of UDP-Lite data + Fragment 2: 1280 bytes carrying 1232 bytes of UDP-Lite data + Fragment 3: 948 bytes carrying 900 bytes of UDP-Lite data + + The first two fragments have to be checksummed in full, of the last + fragment only 598 (= 3062 - 2*1232) bytes are checksummed. + + While it is important that such cases are dealt with correctly, they + are (annoyingly) rare: UDP-Lite is designed for optimising multimedia + performance over wireless (or generally noisy) links and thus smaller + coverage lengths are likely to be expected. + +5. UDP-Lite Runtime Statistics and their Meaning +================================================ + + Exceptional and error conditions are logged to syslog at the KERN_DEBUG + level. Live statistics about UDP-Lite are available in /proc/net/snmp + and can (with newer versions of netstat) be viewed using:: + + netstat -svu + + This displays UDP-Lite statistics variables, whose meaning is as follows. + + ============ ===================================================== + InDatagrams The total number of datagrams delivered to users. + + NoPorts Number of packets received to an unknown port. + These cases are counted separately (not as InErrors). + + InErrors Number of erroneous UDP-Lite packets. Errors include: + + * internal socket queue receive errors + * packet too short (less than 8 bytes or stated + coverage length exceeds received length) + * xfrm4_policy_check() returned with error + * application has specified larger min. coverage + length than that of incoming packet + * checksum coverage violated + * bad checksum + + OutDatagrams Total number of sent datagrams. + ============ ===================================================== + + These statistics derive from the UDP MIB (RFC 2013). + +6. IPtables +=========== + + There is packet match support for UDP-Lite as well as support for the LOG target. + If you copy and paste the following line into /etc/protocols:: + + udplite 136 UDP-Lite # UDP-Lite [RFC 3828] + + then:: + + iptables -A INPUT -p udplite -j LOG + + will produce logging output to syslog. Dropping and rejecting packets also works. + +7. Maintainer Address +===================== + + The UDP-Lite patch was developed at + + University of Aberdeen + Electronics Research Group + Department of Engineering + Fraser Noble Building + Aberdeen AB24 3UE; UK + + The current maintainer is Gerrit Renker, <gerrit@erg.abdn.ac.uk>. Initial + code was developed by William Stanislaus, <william@erg.abdn.ac.uk>. diff --git a/Documentation/networking/vrf.rst b/Documentation/networking/vrf.rst new file mode 100644 index 0000000000..0a9a6f968c --- /dev/null +++ b/Documentation/networking/vrf.rst @@ -0,0 +1,464 @@ +.. SPDX-License-Identifier: GPL-2.0 + +==================================== +Virtual Routing and Forwarding (VRF) +==================================== + +The VRF Device +============== + +The VRF device combined with ip rules provides the ability to create virtual +routing and forwarding domains (aka VRFs, VRF-lite to be specific) in the +Linux network stack. One use case is the multi-tenancy problem where each +tenant has their own unique routing tables and in the very least need +different default gateways. + +Processes can be "VRF aware" by binding a socket to the VRF device. Packets +through the socket then use the routing table associated with the VRF +device. An important feature of the VRF device implementation is that it +impacts only Layer 3 and above so L2 tools (e.g., LLDP) are not affected +(ie., they do not need to be run in each VRF). The design also allows +the use of higher priority ip rules (Policy Based Routing, PBR) to take +precedence over the VRF device rules directing specific traffic as desired. + +In addition, VRF devices allow VRFs to be nested within namespaces. For +example network namespaces provide separation of network interfaces at the +device layer, VLANs on the interfaces within a namespace provide L2 separation +and then VRF devices provide L3 separation. + +Design +------ +A VRF device is created with an associated route table. Network interfaces +are then enslaved to a VRF device:: + + +-----------------------------+ + | vrf-blue | ===> route table 10 + +-----------------------------+ + | | | + +------+ +------+ +-------------+ + | eth1 | | eth2 | ... | bond1 | + +------+ +------+ +-------------+ + | | + +------+ +------+ + | eth8 | | eth9 | + +------+ +------+ + +Packets received on an enslaved device and are switched to the VRF device +in the IPv4 and IPv6 processing stacks giving the impression that packets +flow through the VRF device. Similarly on egress routing rules are used to +send packets to the VRF device driver before getting sent out the actual +interface. This allows tcpdump on a VRF device to capture all packets into +and out of the VRF as a whole\ [1]_. Similarly, netfilter\ [2]_ and tc rules +can be applied using the VRF device to specify rules that apply to the VRF +domain as a whole. + +.. [1] Packets in the forwarded state do not flow through the device, so those + packets are not seen by tcpdump. Will revisit this limitation in a + future release. + +.. [2] Iptables on ingress supports PREROUTING with skb->dev set to the real + ingress device and both INPUT and PREROUTING rules with skb->dev set to + the VRF device. For egress POSTROUTING and OUTPUT rules can be written + using either the VRF device or real egress device. + +Setup +----- +1. VRF device is created with an association to a FIB table. + e.g,:: + + ip link add vrf-blue type vrf table 10 + ip link set dev vrf-blue up + +2. An l3mdev FIB rule directs lookups to the table associated with the device. + A single l3mdev rule is sufficient for all VRFs. The VRF device adds the + l3mdev rule for IPv4 and IPv6 when the first device is created with a + default preference of 1000. Users may delete the rule if desired and add + with a different priority or install per-VRF rules. + + Prior to the v4.8 kernel iif and oif rules are needed for each VRF device:: + + ip ru add oif vrf-blue table 10 + ip ru add iif vrf-blue table 10 + +3. Set the default route for the table (and hence default route for the VRF):: + + ip route add table 10 unreachable default metric 4278198272 + + This high metric value ensures that the default unreachable route can + be overridden by a routing protocol suite. FRRouting interprets + kernel metrics as a combined admin distance (upper byte) and priority + (lower 3 bytes). Thus the above metric translates to [255/8192]. + +4. Enslave L3 interfaces to a VRF device:: + + ip link set dev eth1 master vrf-blue + + Local and connected routes for enslaved devices are automatically moved to + the table associated with VRF device. Any additional routes depending on + the enslaved device are dropped and will need to be reinserted to the VRF + FIB table following the enslavement. + + The IPv6 sysctl option keep_addr_on_down can be enabled to keep IPv6 global + addresses as VRF enslavement changes:: + + sysctl -w net.ipv6.conf.all.keep_addr_on_down=1 + +5. Additional VRF routes are added to associated table:: + + ip route add table 10 ... + + +Applications +------------ +Applications that are to work within a VRF need to bind their socket to the +VRF device:: + + setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, dev, strlen(dev)+1); + +or to specify the output device using cmsg and IP_PKTINFO. + +By default the scope of the port bindings for unbound sockets is +limited to the default VRF. That is, it will not be matched by packets +arriving on interfaces enslaved to an l3mdev and processes may bind to +the same port if they bind to an l3mdev. + +TCP & UDP services running in the default VRF context (ie., not bound +to any VRF device) can work across all VRF domains by enabling the +tcp_l3mdev_accept and udp_l3mdev_accept sysctl options:: + + sysctl -w net.ipv4.tcp_l3mdev_accept=1 + sysctl -w net.ipv4.udp_l3mdev_accept=1 + +These options are disabled by default so that a socket in a VRF is only +selected for packets in that VRF. There is a similar option for RAW +sockets, which is enabled by default for reasons of backwards compatibility. +This is so as to specify the output device with cmsg and IP_PKTINFO, but +using a socket not bound to the corresponding VRF. This allows e.g. older ping +implementations to be run with specifying the device but without executing it +in the VRF. This option can be disabled so that packets received in a VRF +context are only handled by a raw socket bound to the VRF, and packets in the +default VRF are only handled by a socket not bound to any VRF:: + + sysctl -w net.ipv4.raw_l3mdev_accept=0 + +netfilter rules on the VRF device can be used to limit access to services +running in the default VRF context as well. + +Using VRF-aware applications (applications which simultaneously create sockets +outside and inside VRFs) in conjunction with ``net.ipv4.tcp_l3mdev_accept=1`` +is possible but may lead to problems in some situations. With that sysctl +value, it is unspecified which listening socket will be selected to handle +connections for VRF traffic; ie. either a socket bound to the VRF or an unbound +socket may be used to accept new connections from a VRF. This somewhat +unexpected behavior can lead to problems if sockets are configured with extra +options (ex. TCP MD5 keys) with the expectation that VRF traffic will +exclusively be handled by sockets bound to VRFs, as would be the case with +``net.ipv4.tcp_l3mdev_accept=0``. Finally and as a reminder, regardless of +which listening socket is selected, established sockets will be created in the +VRF based on the ingress interface, as documented earlier. + +-------------------------------------------------------------------------------- + +Using iproute2 for VRFs +======================= +iproute2 supports the vrf keyword as of v4.7. For backwards compatibility this +section lists both commands where appropriate -- with the vrf keyword and the +older form without it. + +1. Create a VRF + + To instantiate a VRF device and associate it with a table:: + + $ ip link add dev NAME type vrf table ID + + As of v4.8 the kernel supports the l3mdev FIB rule where a single rule + covers all VRFs. The l3mdev rule is created for IPv4 and IPv6 on first + device create. + +2. List VRFs + + To list VRFs that have been created:: + + $ ip [-d] link show type vrf + NOTE: The -d option is needed to show the table id + + For example:: + + $ ip -d link show type vrf + 11: mgmt: <NOARP,MASTER,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 + link/ether 72:b3:ba:91:e2:24 brd ff:ff:ff:ff:ff:ff promiscuity 0 + vrf table 1 addrgenmode eui64 + 12: red: <NOARP,MASTER,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 + link/ether b6:6f:6e:f6:da:73 brd ff:ff:ff:ff:ff:ff promiscuity 0 + vrf table 10 addrgenmode eui64 + 13: blue: <NOARP,MASTER,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 + link/ether 36:62:e8:7d:bb:8c brd ff:ff:ff:ff:ff:ff promiscuity 0 + vrf table 66 addrgenmode eui64 + 14: green: <NOARP,MASTER,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 + link/ether e6:28:b8:63:70:bb brd ff:ff:ff:ff:ff:ff promiscuity 0 + vrf table 81 addrgenmode eui64 + + + Or in brief output:: + + $ ip -br link show type vrf + mgmt UP 72:b3:ba:91:e2:24 <NOARP,MASTER,UP,LOWER_UP> + red UP b6:6f:6e:f6:da:73 <NOARP,MASTER,UP,LOWER_UP> + blue UP 36:62:e8:7d:bb:8c <NOARP,MASTER,UP,LOWER_UP> + green UP e6:28:b8:63:70:bb <NOARP,MASTER,UP,LOWER_UP> + + +3. Assign a Network Interface to a VRF + + Network interfaces are assigned to a VRF by enslaving the netdevice to a + VRF device:: + + $ ip link set dev NAME master NAME + + On enslavement connected and local routes are automatically moved to the + table associated with the VRF device. + + For example:: + + $ ip link set dev eth0 master mgmt + + +4. Show Devices Assigned to a VRF + + To show devices that have been assigned to a specific VRF add the master + option to the ip command:: + + $ ip link show vrf NAME + $ ip link show master NAME + + For example:: + + $ ip link show vrf red + 3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master red state UP mode DEFAULT group default qlen 1000 + link/ether 02:00:00:00:02:02 brd ff:ff:ff:ff:ff:ff + 4: eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master red state UP mode DEFAULT group default qlen 1000 + link/ether 02:00:00:00:02:03 brd ff:ff:ff:ff:ff:ff + 7: eth5: <BROADCAST,MULTICAST> mtu 1500 qdisc noop master red state DOWN mode DEFAULT group default qlen 1000 + link/ether 02:00:00:00:02:06 brd ff:ff:ff:ff:ff:ff + + + Or using the brief output:: + + $ ip -br link show vrf red + eth1 UP 02:00:00:00:02:02 <BROADCAST,MULTICAST,UP,LOWER_UP> + eth2 UP 02:00:00:00:02:03 <BROADCAST,MULTICAST,UP,LOWER_UP> + eth5 DOWN 02:00:00:00:02:06 <BROADCAST,MULTICAST> + + +5. Show Neighbor Entries for a VRF + + To list neighbor entries associated with devices enslaved to a VRF device + add the master option to the ip command:: + + $ ip [-6] neigh show vrf NAME + $ ip [-6] neigh show master NAME + + For example:: + + $ ip neigh show vrf red + 10.2.1.254 dev eth1 lladdr a6:d9:c7:4f:06:23 REACHABLE + 10.2.2.254 dev eth2 lladdr 5e:54:01:6a:ee:80 REACHABLE + + $ ip -6 neigh show vrf red + 2002:1::64 dev eth1 lladdr a6:d9:c7:4f:06:23 REACHABLE + + +6. Show Addresses for a VRF + + To show addresses for interfaces associated with a VRF add the master + option to the ip command:: + + $ ip addr show vrf NAME + $ ip addr show master NAME + + For example:: + + $ ip addr show vrf red + 3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master red state UP group default qlen 1000 + link/ether 02:00:00:00:02:02 brd ff:ff:ff:ff:ff:ff + inet 10.2.1.2/24 brd 10.2.1.255 scope global eth1 + valid_lft forever preferred_lft forever + inet6 2002:1::2/120 scope global + valid_lft forever preferred_lft forever + inet6 fe80::ff:fe00:202/64 scope link + valid_lft forever preferred_lft forever + 4: eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master red state UP group default qlen 1000 + link/ether 02:00:00:00:02:03 brd ff:ff:ff:ff:ff:ff + inet 10.2.2.2/24 brd 10.2.2.255 scope global eth2 + valid_lft forever preferred_lft forever + inet6 2002:2::2/120 scope global + valid_lft forever preferred_lft forever + inet6 fe80::ff:fe00:203/64 scope link + valid_lft forever preferred_lft forever + 7: eth5: <BROADCAST,MULTICAST> mtu 1500 qdisc noop master red state DOWN group default qlen 1000 + link/ether 02:00:00:00:02:06 brd ff:ff:ff:ff:ff:ff + + Or in brief format:: + + $ ip -br addr show vrf red + eth1 UP 10.2.1.2/24 2002:1::2/120 fe80::ff:fe00:202/64 + eth2 UP 10.2.2.2/24 2002:2::2/120 fe80::ff:fe00:203/64 + eth5 DOWN + + +7. Show Routes for a VRF + + To show routes for a VRF use the ip command to display the table associated + with the VRF device:: + + $ ip [-6] route show vrf NAME + $ ip [-6] route show table ID + + For example:: + + $ ip route show vrf red + unreachable default metric 4278198272 + broadcast 10.2.1.0 dev eth1 proto kernel scope link src 10.2.1.2 + 10.2.1.0/24 dev eth1 proto kernel scope link src 10.2.1.2 + local 10.2.1.2 dev eth1 proto kernel scope host src 10.2.1.2 + broadcast 10.2.1.255 dev eth1 proto kernel scope link src 10.2.1.2 + broadcast 10.2.2.0 dev eth2 proto kernel scope link src 10.2.2.2 + 10.2.2.0/24 dev eth2 proto kernel scope link src 10.2.2.2 + local 10.2.2.2 dev eth2 proto kernel scope host src 10.2.2.2 + broadcast 10.2.2.255 dev eth2 proto kernel scope link src 10.2.2.2 + + $ ip -6 route show vrf red + local 2002:1:: dev lo proto none metric 0 pref medium + local 2002:1::2 dev lo proto none metric 0 pref medium + 2002:1::/120 dev eth1 proto kernel metric 256 pref medium + local 2002:2:: dev lo proto none metric 0 pref medium + local 2002:2::2 dev lo proto none metric 0 pref medium + 2002:2::/120 dev eth2 proto kernel metric 256 pref medium + local fe80:: dev lo proto none metric 0 pref medium + local fe80:: dev lo proto none metric 0 pref medium + local fe80::ff:fe00:202 dev lo proto none metric 0 pref medium + local fe80::ff:fe00:203 dev lo proto none metric 0 pref medium + fe80::/64 dev eth1 proto kernel metric 256 pref medium + fe80::/64 dev eth2 proto kernel metric 256 pref medium + ff00::/8 dev red metric 256 pref medium + ff00::/8 dev eth1 metric 256 pref medium + ff00::/8 dev eth2 metric 256 pref medium + unreachable default dev lo metric 4278198272 error -101 pref medium + +8. Route Lookup for a VRF + + A test route lookup can be done for a VRF:: + + $ ip [-6] route get vrf NAME ADDRESS + $ ip [-6] route get oif NAME ADDRESS + + For example:: + + $ ip route get 10.2.1.40 vrf red + 10.2.1.40 dev eth1 table red src 10.2.1.2 + cache + + $ ip -6 route get 2002:1::32 vrf red + 2002:1::32 from :: dev eth1 table red proto kernel src 2002:1::2 metric 256 pref medium + + +9. Removing Network Interface from a VRF + + Network interfaces are removed from a VRF by breaking the enslavement to + the VRF device:: + + $ ip link set dev NAME nomaster + + Connected routes are moved back to the default table and local entries are + moved to the local table. + + For example:: + + $ ip link set dev eth0 nomaster + +-------------------------------------------------------------------------------- + +Commands used in this example:: + + cat >> /etc/iproute2/rt_tables.d/vrf.conf <<EOF + 1 mgmt + 10 red + 66 blue + 81 green + EOF + + function vrf_create + { + VRF=$1 + TBID=$2 + + # create VRF device + ip link add ${VRF} type vrf table ${TBID} + + if [ "${VRF}" != "mgmt" ]; then + ip route add table ${TBID} unreachable default metric 4278198272 + fi + ip link set dev ${VRF} up + } + + vrf_create mgmt 1 + ip link set dev eth0 master mgmt + + vrf_create red 10 + ip link set dev eth1 master red + ip link set dev eth2 master red + ip link set dev eth5 master red + + vrf_create blue 66 + ip link set dev eth3 master blue + + vrf_create green 81 + ip link set dev eth4 master green + + + Interface addresses from /etc/network/interfaces: + auto eth0 + iface eth0 inet static + address 10.0.0.2 + netmask 255.255.255.0 + gateway 10.0.0.254 + + iface eth0 inet6 static + address 2000:1::2 + netmask 120 + + auto eth1 + iface eth1 inet static + address 10.2.1.2 + netmask 255.255.255.0 + + iface eth1 inet6 static + address 2002:1::2 + netmask 120 + + auto eth2 + iface eth2 inet static + address 10.2.2.2 + netmask 255.255.255.0 + + iface eth2 inet6 static + address 2002:2::2 + netmask 120 + + auto eth3 + iface eth3 inet static + address 10.2.3.2 + netmask 255.255.255.0 + + iface eth3 inet6 static + address 2002:3::2 + netmask 120 + + auto eth4 + iface eth4 inet static + address 10.2.4.2 + netmask 255.255.255.0 + + iface eth4 inet6 static + address 2002:4::2 + netmask 120 diff --git a/Documentation/networking/vxlan.rst b/Documentation/networking/vxlan.rst new file mode 100644 index 0000000000..2759dc1cc5 --- /dev/null +++ b/Documentation/networking/vxlan.rst @@ -0,0 +1,88 @@ +.. SPDX-License-Identifier: GPL-2.0 + +====================================================== +Virtual eXtensible Local Area Networking documentation +====================================================== + +The VXLAN protocol is a tunnelling protocol designed to solve the +problem of limited VLAN IDs (4096) in IEEE 802.1q. With VXLAN the +size of the identifier is expanded to 24 bits (16777216). + +VXLAN is described by IETF RFC 7348, and has been implemented by a +number of vendors. The protocol runs over UDP using a single +destination port. This document describes the Linux kernel tunnel +device, there is also a separate implementation of VXLAN for +Openvswitch. + +Unlike most tunnels, a VXLAN is a 1 to N network, not just point to +point. A VXLAN device can learn the IP address of the other endpoint +either dynamically in a manner similar to a learning bridge, or make +use of statically-configured forwarding entries. + +The management of vxlan is done in a manner similar to its two closest +neighbors GRE and VLAN. Configuring VXLAN requires the version of +iproute2 that matches the kernel release where VXLAN was first merged +upstream. + +1. Create vxlan device:: + + # ip link add vxlan0 type vxlan id 42 group 239.1.1.1 dev eth1 dstport 4789 + +This creates a new device named vxlan0. The device uses the multicast +group 239.1.1.1 over eth1 to handle traffic for which there is no +entry in the forwarding table. The destination port number is set to +the IANA-assigned value of 4789. The Linux implementation of VXLAN +pre-dates the IANA's selection of a standard destination port number +and uses the Linux-selected value by default to maintain backwards +compatibility. + +2. Delete vxlan device:: + + # ip link delete vxlan0 + +3. Show vxlan info:: + + # ip -d link show vxlan0 + +It is possible to create, destroy and display the vxlan +forwarding table using the new bridge command. + +1. Create forwarding table entry:: + + # bridge fdb add to 00:17:42:8a:b4:05 dst 192.19.0.2 dev vxlan0 + +2. Delete forwarding table entry:: + + # bridge fdb delete 00:17:42:8a:b4:05 dev vxlan0 + +3. Show forwarding table:: + + # bridge fdb show dev vxlan0 + +The following NIC features may indicate support for UDP tunnel-related +offloads (most commonly VXLAN features, but support for a particular +encapsulation protocol is NIC specific): + + - `tx-udp_tnl-segmentation` + - `tx-udp_tnl-csum-segmentation` + ability to perform TCP segmentation offload of UDP encapsulated frames + + - `rx-udp_tunnel-port-offload` + receive side parsing of UDP encapsulated frames which allows NICs to + perform protocol-aware offloads, like checksum validation offload of + inner frames (only needed by NICs without protocol-agnostic offloads) + +For devices supporting `rx-udp_tunnel-port-offload` the list of currently +offloaded ports can be interrogated with `ethtool`:: + + $ ethtool --show-tunnels eth0 + Tunnel information for eth0: + UDP port table 0: + Size: 4 + Types: vxlan + No entries + UDP port table 1: + Size: 4 + Types: geneve, vxlan-gpe + Entries (1): + port 1230, vxlan-gpe diff --git a/Documentation/networking/x25-iface.rst b/Documentation/networking/x25-iface.rst new file mode 100644 index 0000000000..285cefcfce --- /dev/null +++ b/Documentation/networking/x25-iface.rst @@ -0,0 +1,81 @@ +.. SPDX-License-Identifier: GPL-2.0 + +X.25 Device Driver Interface +============================ + +Version 1.1 + + Jonathan Naylor 26.12.96 + +This is a description of the messages to be passed between the X.25 Packet +Layer and the X.25 device driver. They are designed to allow for the easy +setting of the LAPB mode from within the Packet Layer. + +The X.25 device driver will be coded normally as per the Linux device driver +standards. Most X.25 device drivers will be moderately similar to the +already existing Ethernet device drivers. However unlike those drivers, the +X.25 device driver has a state associated with it, and this information +needs to be passed to and from the Packet Layer for proper operation. + +All messages are held in sk_buff's just like real data to be transmitted +over the LAPB link. The first byte of the skbuff indicates the meaning of +the rest of the skbuff, if any more information does exist. + + +Packet Layer to Device Driver +----------------------------- + +First Byte = 0x00 (X25_IFACE_DATA) + +This indicates that the rest of the skbuff contains data to be transmitted +over the LAPB link. The LAPB link should already exist before any data is +passed down. + +First Byte = 0x01 (X25_IFACE_CONNECT) + +Establish the LAPB link. If the link is already established then the connect +confirmation message should be returned as soon as possible. + +First Byte = 0x02 (X25_IFACE_DISCONNECT) + +Terminate the LAPB link. If it is already disconnected then the disconnect +confirmation message should be returned as soon as possible. + +First Byte = 0x03 (X25_IFACE_PARAMS) + +LAPB parameters. To be defined. + + +Device Driver to Packet Layer +----------------------------- + +First Byte = 0x00 (X25_IFACE_DATA) + +This indicates that the rest of the skbuff contains data that has been +received over the LAPB link. + +First Byte = 0x01 (X25_IFACE_CONNECT) + +LAPB link has been established. The same message is used for both a LAPB +link connect_confirmation and a connect_indication. + +First Byte = 0x02 (X25_IFACE_DISCONNECT) + +LAPB link has been terminated. This same message is used for both a LAPB +link disconnect_confirmation and a disconnect_indication. + +First Byte = 0x03 (X25_IFACE_PARAMS) + +LAPB parameters. To be defined. + + +Requirements for the device driver +---------------------------------- + +Packets should not be reordered or dropped when delivering between the +Packet Layer and the device driver. + +To avoid packets from being reordered or dropped when delivering from +the device driver to the Packet Layer, the device driver should not +call "netif_rx" to deliver the received packets. Instead, it should +call "netif_receive_skb_core" from softirq context to deliver them. diff --git a/Documentation/networking/x25.rst b/Documentation/networking/x25.rst new file mode 100644 index 0000000000..e11d9ebdf9 --- /dev/null +++ b/Documentation/networking/x25.rst @@ -0,0 +1,46 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================== +Linux X.25 Project +================== + +As my third year dissertation at University I have taken it upon myself to +write an X.25 implementation for Linux. My aim is to provide a complete X.25 +Packet Layer and a LAPB module to allow for "normal" X.25 to be run using +Linux. There are two sorts of X.25 cards available, intelligent ones that +implement LAPB on the card itself, and unintelligent ones that simply do +framing, bit-stuffing and checksumming. These both need to be handled by the +system. + +I therefore decided to write the implementation such that as far as the +Packet Layer is concerned, the link layer was being performed by a lower +layer of the Linux kernel and therefore it did not concern itself with +implementation of LAPB. Therefore the LAPB modules would be called by +unintelligent X.25 card drivers and not by intelligent ones, this would +provide a uniform device driver interface, and simplify configuration. + +To confuse matters a little, an 802.2 LLC implementation is also possible +which could allow X.25 to be run over an Ethernet (or Token Ring) and +conform with the JNT "Pink Book", this would have a different interface to +the Packet Layer but there would be no confusion since the class of device +being served by the LLC would be completely separate from LAPB. + +Just when you thought that it could not become more confusing, another +option appeared, XOT. This allows X.25 Packet Layer frames to operate over +the Internet using TCP/IP as a reliable link layer. RFC1613 specifies the +format and behaviour of the protocol. If time permits this option will also +be actively considered. + +A linux-x25 mailing list has been created at vger.kernel.org to support the +development and use of Linux X.25. It is early days yet, but interested +parties are welcome to subscribe to it. Just send a message to +majordomo@vger.kernel.org with the following in the message body: + +subscribe linux-x25 +end + +The contents of the Subject line are ignored. + +Jonathan + +g4klx@g4klx.demon.co.uk diff --git a/Documentation/networking/xdp-rx-metadata.rst b/Documentation/networking/xdp-rx-metadata.rst new file mode 100644 index 0000000000..25ce72af81 --- /dev/null +++ b/Documentation/networking/xdp-rx-metadata.rst @@ -0,0 +1,113 @@ +=============== +XDP RX Metadata +=============== + +This document describes how an eXpress Data Path (XDP) program can access +hardware metadata related to a packet using a set of helper functions, +and how it can pass that metadata on to other consumers. + +General Design +============== + +XDP has access to a set of kfuncs to manipulate the metadata in an XDP frame. +Every device driver that wishes to expose additional packet metadata can +implement these kfuncs. The set of kfuncs is declared in ``include/net/xdp.h`` +via ``XDP_METADATA_KFUNC_xxx``. + +Currently, the following kfuncs are supported. In the future, as more +metadata is supported, this set will grow: + +.. kernel-doc:: net/core/xdp.c + :identifiers: bpf_xdp_metadata_rx_timestamp bpf_xdp_metadata_rx_hash + +An XDP program can use these kfuncs to read the metadata into stack +variables for its own consumption. Or, to pass the metadata on to other +consumers, an XDP program can store it into the metadata area carried +ahead of the packet. Not all packets will necessary have the requested +metadata available in which case the driver returns ``-ENODATA``. + +Not all kfuncs have to be implemented by the device driver; when not +implemented, the default ones that return ``-EOPNOTSUPP`` will be used +to indicate the device driver have not implemented this kfunc. + + +Within an XDP frame, the metadata layout (accessed via ``xdp_buff``) is +as follows:: + + +----------+-----------------+------+ + | headroom | custom metadata | data | + +----------+-----------------+------+ + ^ ^ + | | + xdp_buff->data_meta xdp_buff->data + +An XDP program can store individual metadata items into this ``data_meta`` +area in whichever format it chooses. Later consumers of the metadata +will have to agree on the format by some out of band contract (like for +the AF_XDP use case, see below). + +AF_XDP +====== + +:doc:`af_xdp` use-case implies that there is a contract between the BPF +program that redirects XDP frames into the ``AF_XDP`` socket (``XSK``) and +the final consumer. Thus the BPF program manually allocates a fixed number of +bytes out of metadata via ``bpf_xdp_adjust_meta`` and calls a subset +of kfuncs to populate it. The userspace ``XSK`` consumer computes +``xsk_umem__get_data() - METADATA_SIZE`` to locate that metadata. +Note, ``xsk_umem__get_data`` is defined in ``libxdp`` and +``METADATA_SIZE`` is an application-specific constant (``AF_XDP`` receive +descriptor does _not_ explicitly carry the size of the metadata). + +Here is the ``AF_XDP`` consumer layout (note missing ``data_meta`` pointer):: + + +----------+-----------------+------+ + | headroom | custom metadata | data | + +----------+-----------------+------+ + ^ + | + rx_desc->address + +XDP_PASS +======== + +This is the path where the packets processed by the XDP program are passed +into the kernel. The kernel creates the ``skb`` out of the ``xdp_buff`` +contents. Currently, every driver has custom kernel code to parse +the descriptors and populate ``skb`` metadata when doing this ``xdp_buff->skb`` +conversion, and the XDP metadata is not used by the kernel when building +``skbs``. However, TC-BPF programs can access the XDP metadata area using +the ``data_meta`` pointer. + +In the future, we'd like to support a case where an XDP program +can override some of the metadata used for building ``skbs``. + +bpf_redirect_map +================ + +``bpf_redirect_map`` can redirect the frame to a different device. +Some devices (like virtual ethernet links) support running a second XDP +program after the redirect. However, the final consumer doesn't have +access to the original hardware descriptor and can't access any of +the original metadata. The same applies to XDP programs installed +into devmaps and cpumaps. + +This means that for redirected packets only custom metadata is +currently supported, which has to be prepared by the initial XDP program +before redirect. If the frame is eventually passed to the kernel, the +``skb`` created from such a frame won't have any hardware metadata populated +in its ``skb``. If such a packet is later redirected into an ``XSK``, +that will also only have access to the custom metadata. + +bpf_tail_call +============= + +Adding programs that access metadata kfuncs to the ``BPF_MAP_TYPE_PROG_ARRAY`` +is currently not supported. + +Example +======= + +See ``tools/testing/selftests/bpf/progs/xdp_metadata.c`` and +``tools/testing/selftests/bpf/prog_tests/xdp_metadata.c`` for an example of +BPF program that handles XDP metadata. diff --git a/Documentation/networking/xfrm_device.rst b/Documentation/networking/xfrm_device.rst new file mode 100644 index 0000000000..535077cbeb --- /dev/null +++ b/Documentation/networking/xfrm_device.rst @@ -0,0 +1,196 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. _xfrm_device: + +=============================================== +XFRM device - offloading the IPsec computations +=============================================== + +Shannon Nelson <shannon.nelson@oracle.com> +Leon Romanovsky <leonro@nvidia.com> + + +Overview +======== + +IPsec is a useful feature for securing network traffic, but the +computational cost is high: a 10Gbps link can easily be brought down +to under 1Gbps, depending on the traffic and link configuration. +Luckily, there are NICs that offer a hardware based IPsec offload which +can radically increase throughput and decrease CPU utilization. The XFRM +Device interface allows NIC drivers to offer to the stack access to the +hardware offload. + +Right now, there are two types of hardware offload that kernel supports. + * IPsec crypto offload: + * NIC performs encrypt/decrypt + * Kernel does everything else + * IPsec packet offload: + * NIC performs encrypt/decrypt + * NIC does encapsulation + * Kernel and NIC have SA and policy in-sync + * NIC handles the SA and policies states + * The Kernel talks to the keymanager + +Userland access to the offload is typically through a system such as +libreswan or KAME/raccoon, but the iproute2 'ip xfrm' command set can +be handy when experimenting. An example command might look something +like this for crypto offload: + + ip x s add proto esp dst 14.0.0.70 src 14.0.0.52 spi 0x07 mode transport \ + reqid 0x07 replay-window 32 \ + aead 'rfc4106(gcm(aes))' 0x44434241343332312423222114131211f4f3f2f1 128 \ + sel src 14.0.0.52/24 dst 14.0.0.70/24 proto tcp \ + offload dev eth4 dir in + +and for packet offload + + ip x s add proto esp dst 14.0.0.70 src 14.0.0.52 spi 0x07 mode transport \ + reqid 0x07 replay-window 32 \ + aead 'rfc4106(gcm(aes))' 0x44434241343332312423222114131211f4f3f2f1 128 \ + sel src 14.0.0.52/24 dst 14.0.0.70/24 proto tcp \ + offload packet dev eth4 dir in + + ip x p add src 14.0.0.70 dst 14.0.0.52 offload packet dev eth4 dir in + tmpl src 14.0.0.70 dst 14.0.0.52 proto esp reqid 10000 mode transport + +Yes, that's ugly, but that's what shell scripts and/or libreswan are for. + + + +Callbacks to implement +====================== + +:: + + /* from include/linux/netdevice.h */ + struct xfrmdev_ops { + /* Crypto and Packet offload callbacks */ + int (*xdo_dev_state_add) (struct xfrm_state *x, struct netlink_ext_ack *extack); + void (*xdo_dev_state_delete) (struct xfrm_state *x); + void (*xdo_dev_state_free) (struct xfrm_state *x); + bool (*xdo_dev_offload_ok) (struct sk_buff *skb, + struct xfrm_state *x); + void (*xdo_dev_state_advance_esn) (struct xfrm_state *x); + + /* Solely packet offload callbacks */ + void (*xdo_dev_state_update_curlft) (struct xfrm_state *x); + int (*xdo_dev_policy_add) (struct xfrm_policy *x, struct netlink_ext_ack *extack); + void (*xdo_dev_policy_delete) (struct xfrm_policy *x); + void (*xdo_dev_policy_free) (struct xfrm_policy *x); + }; + +The NIC driver offering ipsec offload will need to implement callbacks +relevant to supported offload to make the offload available to the network +stack's XFRM subsystem. Additionally, the feature bits NETIF_F_HW_ESP and +NETIF_F_HW_ESP_TX_CSUM will signal the availability of the offload. + + + +Flow +==== + +At probe time and before the call to register_netdev(), the driver should +set up local data structures and XFRM callbacks, and set the feature bits. +The XFRM code's listener will finish the setup on NETDEV_REGISTER. + +:: + + adapter->netdev->xfrmdev_ops = &ixgbe_xfrmdev_ops; + adapter->netdev->features |= NETIF_F_HW_ESP; + adapter->netdev->hw_enc_features |= NETIF_F_HW_ESP; + +When new SAs are set up with a request for "offload" feature, the +driver's xdo_dev_state_add() will be given the new SA to be offloaded +and an indication of whether it is for Rx or Tx. The driver should + + - verify the algorithm is supported for offloads + - store the SA information (key, salt, target-ip, protocol, etc) + - enable the HW offload of the SA + - return status value: + + =========== =================================== + 0 success + -EOPNETSUPP offload not supported, try SW IPsec, + not applicable for packet offload mode + other fail the request + =========== =================================== + +The driver can also set an offload_handle in the SA, an opaque void pointer +that can be used to convey context into the fast-path offload requests:: + + xs->xso.offload_handle = context; + + +When the network stack is preparing an IPsec packet for an SA that has +been setup for offload, it first calls into xdo_dev_offload_ok() with +the skb and the intended offload state to ask the driver if the offload +will serviceable. This can check the packet information to be sure the +offload can be supported (e.g. IPv4 or IPv6, no IPv4 options, etc) and +return true of false to signify its support. + +Crypto offload mode: +When ready to send, the driver needs to inspect the Tx packet for the +offload information, including the opaque context, and set up the packet +send accordingly:: + + xs = xfrm_input_state(skb); + context = xs->xso.offload_handle; + set up HW for send + +The stack has already inserted the appropriate IPsec headers in the +packet data, the offload just needs to do the encryption and fix up the +header values. + + +When a packet is received and the HW has indicated that it offloaded a +decryption, the driver needs to add a reference to the decoded SA into +the packet's skb. At this point the data should be decrypted but the +IPsec headers are still in the packet data; they are removed later up +the stack in xfrm_input(). + + find and hold the SA that was used to the Rx skb:: + + get spi, protocol, and destination IP from packet headers + xs = find xs from (spi, protocol, dest_IP) + xfrm_state_hold(xs); + + store the state information into the skb:: + + sp = secpath_set(skb); + if (!sp) return; + sp->xvec[sp->len++] = xs; + sp->olen++; + + indicate the success and/or error status of the offload:: + + xo = xfrm_offload(skb); + xo->flags = CRYPTO_DONE; + xo->status = crypto_status; + + hand the packet to napi_gro_receive() as usual + +In ESN mode, xdo_dev_state_advance_esn() is called from xfrm_replay_advance_esn(). +Driver will check packet seq number and update HW ESN state machine if needed. + +Packet offload mode: +HW adds and deletes XFRM headers. So in RX path, XFRM stack is bypassed if HW +reported success. In TX path, the packet lefts kernel without extra header +and not encrypted, the HW is responsible to perform it. + +When the SA is removed by the user, the driver's xdo_dev_state_delete() +and xdo_dev_policy_delete() are asked to disable the offload. Later, +xdo_dev_state_free() and xdo_dev_policy_free() are called from a garbage +collection routine after all reference counts to the state and policy +have been removed and any remaining resources can be cleared for the +offload state. How these are used by the driver will depend on specific +hardware needs. + +As a netdev is set to DOWN the XFRM stack's netdev listener will call +xdo_dev_state_delete(), xdo_dev_policy_delete(), xdo_dev_state_free() and +xdo_dev_policy_free() on any remaining offloaded states. + +Outcome of HW handling packets, the XFRM core can't count hard, soft limits. +The HW/driver are responsible to perform it and provide accurate data when +xdo_dev_state_update_curlft() is called. In case of one of these limits +occuried, the driver needs to call to xfrm_state_check_expire() to make sure +that XFRM performs rekeying sequence. diff --git a/Documentation/networking/xfrm_proc.rst b/Documentation/networking/xfrm_proc.rst new file mode 100644 index 0000000000..0a771c5a73 --- /dev/null +++ b/Documentation/networking/xfrm_proc.rst @@ -0,0 +1,113 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================================== +XFRM proc - /proc/net/xfrm_* files +================================== + +Masahide NAKAMURA <nakam@linux-ipv6.org> + + +Transformation Statistics +------------------------- + +The xfrm_proc code is a set of statistics showing numbers of packets +dropped by the transformation code and why. These counters are defined +as part of the linux private MIB. These counters can be viewed in +/proc/net/xfrm_stat. + + +Inbound errors +~~~~~~~~~~~~~~ + +XfrmInError: + All errors which is not matched others + +XfrmInBufferError: + No buffer is left + +XfrmInHdrError: + Header error + +XfrmInNoStates: + No state is found + i.e. Either inbound SPI, address, or IPsec protocol at SA is wrong + +XfrmInStateProtoError: + Transformation protocol specific error + e.g. SA key is wrong + +XfrmInStateModeError: + Transformation mode specific error + +XfrmInStateSeqError: + Sequence error + i.e. Sequence number is out of window + +XfrmInStateExpired: + State is expired + +XfrmInStateMismatch: + State has mismatch option + e.g. UDP encapsulation type is mismatch + +XfrmInStateInvalid: + State is invalid + +XfrmInTmplMismatch: + No matching template for states + e.g. Inbound SAs are correct but SP rule is wrong + +XfrmInNoPols: + No policy is found for states + e.g. Inbound SAs are correct but no SP is found + +XfrmInPolBlock: + Policy discards + +XfrmInPolError: + Policy error + +XfrmAcquireError: + State hasn't been fully acquired before use + +XfrmFwdHdrError: + Forward routing of a packet is not allowed + +Outbound errors +~~~~~~~~~~~~~~~ +XfrmOutError: + All errors which is not matched others + +XfrmOutBundleGenError: + Bundle generation error + +XfrmOutBundleCheckError: + Bundle check error + +XfrmOutNoStates: + No state is found + +XfrmOutStateProtoError: + Transformation protocol specific error + +XfrmOutStateModeError: + Transformation mode specific error + +XfrmOutStateSeqError: + Sequence error + i.e. Sequence number overflow + +XfrmOutStateExpired: + State is expired + +XfrmOutPolBlock: + Policy discards + +XfrmOutPolDead: + Policy is dead + +XfrmOutPolError: + Policy error + +XfrmOutStateInvalid: + State is invalid, perhaps expired diff --git a/Documentation/networking/xfrm_sync.rst b/Documentation/networking/xfrm_sync.rst new file mode 100644 index 0000000000..6246503cea --- /dev/null +++ b/Documentation/networking/xfrm_sync.rst @@ -0,0 +1,189 @@ +.. SPDX-License-Identifier: GPL-2.0 + +==== +XFRM +==== + +The sync patches work is based on initial patches from +Krisztian <hidden@balabit.hu> and others and additional patches +from Jamal <hadi@cyberus.ca>. + +The end goal for syncing is to be able to insert attributes + generate +events so that the SA can be safely moved from one machine to another +for HA purposes. +The idea is to synchronize the SA so that the takeover machine can do +the processing of the SA as accurate as possible if it has access to it. + +We already have the ability to generate SA add/del/upd events. +These patches add ability to sync and have accurate lifetime byte (to +ensure proper decay of SAs) and replay counters to avoid replay attacks +with as minimal loss at failover time. +This way a backup stays as closely up-to-date as an active member. + +Because the above items change for every packet the SA receives, +it is possible for a lot of the events to be generated. +For this reason, we also add a nagle-like algorithm to restrict +the events. i.e we are going to set thresholds to say "let me +know if the replay sequence threshold is reached or 10 secs have passed" +These thresholds are set system-wide via sysctls or can be updated +per SA. + +The identified items that need to be synchronized are: +- the lifetime byte counter +note that: lifetime time limit is not important if you assume the failover +machine is known ahead of time since the decay of the time countdown +is not driven by packet arrival. +- the replay sequence for both inbound and outbound + +1) Message Structure +---------------------- + +nlmsghdr:aevent_id:optional-TLVs. + +The netlink message types are: + +XFRM_MSG_NEWAE and XFRM_MSG_GETAE. + +A XFRM_MSG_GETAE does not have TLVs. + +A XFRM_MSG_NEWAE will have at least two TLVs (as is +discussed further below). + +aevent_id structure looks like:: + + struct xfrm_aevent_id { + struct xfrm_usersa_id sa_id; + xfrm_address_t saddr; + __u32 flags; + __u32 reqid; + }; + +The unique SA is identified by the combination of xfrm_usersa_id, +reqid and saddr. + +flags are used to indicate different things. The possible +flags are:: + + XFRM_AE_RTHR=1, /* replay threshold*/ + XFRM_AE_RVAL=2, /* replay value */ + XFRM_AE_LVAL=4, /* lifetime value */ + XFRM_AE_ETHR=8, /* expiry timer threshold */ + XFRM_AE_CR=16, /* Event cause is replay update */ + XFRM_AE_CE=32, /* Event cause is timer expiry */ + XFRM_AE_CU=64, /* Event cause is policy update */ + +How these flags are used is dependent on the direction of the +message (kernel<->user) as well the cause (config, query or event). +This is described below in the different messages. + +The pid will be set appropriately in netlink to recognize direction +(0 to the kernel and pid = processid that created the event +when going from kernel to user space) + +A program needs to subscribe to multicast group XFRMNLGRP_AEVENTS +to get notified of these events. + +2) TLVS reflect the different parameters: +----------------------------------------- + +a) byte value (XFRMA_LTIME_VAL) + +This TLV carries the running/current counter for byte lifetime since +last event. + +b)replay value (XFRMA_REPLAY_VAL) + +This TLV carries the running/current counter for replay sequence since +last event. + +c)replay threshold (XFRMA_REPLAY_THRESH) + +This TLV carries the threshold being used by the kernel to trigger events +when the replay sequence is exceeded. + +d) expiry timer (XFRMA_ETIMER_THRESH) + +This is a timer value in milliseconds which is used as the nagle +value to rate limit the events. + +3) Default configurations for the parameters: +--------------------------------------------- + +By default these events should be turned off unless there is +at least one listener registered to listen to the multicast +group XFRMNLGRP_AEVENTS. + +Programs installing SAs will need to specify the two thresholds, however, +in order to not change existing applications such as racoon +we also provide default threshold values for these different parameters +in case they are not specified. + +the two sysctls/proc entries are: + +a) /proc/sys/net/core/sysctl_xfrm_aevent_etime +used to provide default values for the XFRMA_ETIMER_THRESH in incremental +units of time of 100ms. The default is 10 (1 second) + +b) /proc/sys/net/core/sysctl_xfrm_aevent_rseqth +used to provide default values for XFRMA_REPLAY_THRESH parameter +in incremental packet count. The default is two packets. + +4) Message types +---------------- + +a) XFRM_MSG_GETAE issued by user-->kernel. + XFRM_MSG_GETAE does not carry any TLVs. + +The response is a XFRM_MSG_NEWAE which is formatted based on what +XFRM_MSG_GETAE queried for. + +The response will always have XFRMA_LTIME_VAL and XFRMA_REPLAY_VAL TLVs. +* if XFRM_AE_RTHR flag is set, then XFRMA_REPLAY_THRESH is also retrieved +* if XFRM_AE_ETHR flag is set, then XFRMA_ETIMER_THRESH is also retrieved + +b) XFRM_MSG_NEWAE is issued by either user space to configure + or kernel to announce events or respond to a XFRM_MSG_GETAE. + +i) user --> kernel to configure a specific SA. + +any of the values or threshold parameters can be updated by passing the +appropriate TLV. + +A response is issued back to the sender in user space to indicate success +or failure. + +In the case of success, additionally an event with +XFRM_MSG_NEWAE is also issued to any listeners as described in iii). + +ii) kernel->user direction as a response to XFRM_MSG_GETAE + +The response will always have XFRMA_LTIME_VAL and XFRMA_REPLAY_VAL TLVs. + +The threshold TLVs will be included if explicitly requested in +the XFRM_MSG_GETAE message. + +iii) kernel->user to report as event if someone sets any values or + thresholds for an SA using XFRM_MSG_NEWAE (as described in #i above). + In such a case XFRM_AE_CU flag is set to inform the user that + the change happened as a result of an update. + The message will always have XFRMA_LTIME_VAL and XFRMA_REPLAY_VAL TLVs. + +iv) kernel->user to report event when replay threshold or a timeout + is exceeded. + +In such a case either XFRM_AE_CR (replay exceeded) or XFRM_AE_CE (timeout +happened) is set to inform the user what happened. +Note the two flags are mutually exclusive. +The message will always have XFRMA_LTIME_VAL and XFRMA_REPLAY_VAL TLVs. + +Exceptions to threshold settings +-------------------------------- + +If you have an SA that is getting hit by traffic in bursts such that +there is a period where the timer threshold expires with no packets +seen, then an odd behavior is seen as follows: +The first packet arrival after a timer expiry will trigger a timeout +event; i.e we don't wait for a timeout period or a packet threshold +to be reached. This is done for simplicity and efficiency reasons. + +-JHS diff --git a/Documentation/networking/xfrm_sysctl.rst b/Documentation/networking/xfrm_sysctl.rst new file mode 100644 index 0000000000..47b9bbdd01 --- /dev/null +++ b/Documentation/networking/xfrm_sysctl.rst @@ -0,0 +1,11 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============ +XFRM Syscall +============ + +/proc/sys/net/core/xfrm_* Variables: +==================================== + +xfrm_acq_expires - INTEGER + default 30 - hard timeout in seconds for acquire requests |
