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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /Documentation/networking/x25-iface.rst | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'Documentation/networking/x25-iface.rst')
-rw-r--r-- | Documentation/networking/x25-iface.rst | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/Documentation/networking/x25-iface.rst b/Documentation/networking/x25-iface.rst new file mode 100644 index 000000000..f34e9ec64 --- /dev/null +++ b/Documentation/networking/x25-iface.rst @@ -0,0 +1,82 @@ +.. 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. |