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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /tools/bpf/bpftool/Documentation/bpftool-map.rst
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Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+
+================
+bpftool-map
+================
+-------------------------------------------------------------------------------
+tool for inspection and simple manipulation of eBPF maps
+-------------------------------------------------------------------------------
+
+:Manual section: 8
+
+.. include:: substitutions.rst
+
+SYNOPSIS
+========
+
+ **bpftool** [*OPTIONS*] **map** *COMMAND*
+
+ *OPTIONS* := { |COMMON_OPTIONS| | { **-f** | **--bpffs** } | { **-n** | **--nomount** } }
+
+ *COMMANDS* :=
+ { **show** | **list** | **create** | **dump** | **update** | **lookup** | **getnext** |
+ **delete** | **pin** | **help** }
+
+MAP COMMANDS
+=============
+
+| **bpftool** **map** { **show** | **list** } [*MAP*]
+| **bpftool** **map create** *FILE* **type** *TYPE* **key** *KEY_SIZE* **value** *VALUE_SIZE* \
+| **entries** *MAX_ENTRIES* **name** *NAME* [**flags** *FLAGS*] [**inner_map** *MAP*] \
+| [**offload_dev** *NAME*]
+| **bpftool** **map dump** *MAP*
+| **bpftool** **map update** *MAP* [**key** *DATA*] [**value** *VALUE*] [*UPDATE_FLAGS*]
+| **bpftool** **map lookup** *MAP* [**key** *DATA*]
+| **bpftool** **map getnext** *MAP* [**key** *DATA*]
+| **bpftool** **map delete** *MAP* **key** *DATA*
+| **bpftool** **map pin** *MAP* *FILE*
+| **bpftool** **map event_pipe** *MAP* [**cpu** *N* **index** *M*]
+| **bpftool** **map peek** *MAP*
+| **bpftool** **map push** *MAP* **value** *VALUE*
+| **bpftool** **map pop** *MAP*
+| **bpftool** **map enqueue** *MAP* **value** *VALUE*
+| **bpftool** **map dequeue** *MAP*
+| **bpftool** **map freeze** *MAP*
+| **bpftool** **map help**
+|
+| *MAP* := { **id** *MAP_ID* | **pinned** *FILE* | **name** *MAP_NAME* }
+| *DATA* := { [**hex**] *BYTES* }
+| *PROG* := { **id** *PROG_ID* | **pinned** *FILE* | **tag** *PROG_TAG* | **name** *PROG_NAME* }
+| *VALUE* := { *DATA* | *MAP* | *PROG* }
+| *UPDATE_FLAGS* := { **any** | **exist** | **noexist** }
+| *TYPE* := { **hash** | **array** | **prog_array** | **perf_event_array** | **percpu_hash**
+| | **percpu_array** | **stack_trace** | **cgroup_array** | **lru_hash**
+| | **lru_percpu_hash** | **lpm_trie** | **array_of_maps** | **hash_of_maps**
+| | **devmap** | **devmap_hash** | **sockmap** | **cpumap** | **xskmap** | **sockhash**
+| | **cgroup_storage** | **reuseport_sockarray** | **percpu_cgroup_storage**
+| | **queue** | **stack** | **sk_storage** | **struct_ops** | **ringbuf** | **inode_storage**
+| | **task_storage** | **bloom_filter** | **user_ringbuf** | **cgrp_storage** }
+
+DESCRIPTION
+===========
+ **bpftool map { show | list }** [*MAP*]
+ Show information about loaded maps. If *MAP* is specified
+ show information only about given maps, otherwise list all
+ maps currently loaded on the system. In case of **name**,
+ *MAP* may match several maps which will all be shown.
+
+ Output will start with map ID followed by map type and
+ zero or more named attributes (depending on kernel version).
+
+ Since Linux 5.8 bpftool is able to discover information about
+ processes that hold open file descriptors (FDs) against BPF
+ maps. On such kernels bpftool will automatically emit this
+ information as well.
+
+ **bpftool map create** *FILE* **type** *TYPE* **key** *KEY_SIZE* **value** *VALUE_SIZE* **entries** *MAX_ENTRIES* **name** *NAME* [**flags** *FLAGS*] [**inner_map** *MAP*] [**offload_dev** *NAME*]
+ Create a new map with given parameters and pin it to *bpffs*
+ as *FILE*.
+
+ *FLAGS* should be an integer which is the combination of
+ desired flags, e.g. 1024 for **BPF_F_MMAPABLE** (see bpf.h
+ UAPI header for existing flags).
+
+ To create maps of type array-of-maps or hash-of-maps, the
+ **inner_map** keyword must be used to pass an inner map. The
+ kernel needs it to collect metadata related to the inner maps
+ that the new map will work with.
+
+ Keyword **offload_dev** expects a network interface name,
+ and is used to request hardware offload for the map.
+
+ **bpftool map dump** *MAP*
+ Dump all entries in a given *MAP*. In case of **name**,
+ *MAP* may match several maps which will all be dumped.
+
+ **bpftool map update** *MAP* [**key** *DATA*] [**value** *VALUE*] [*UPDATE_FLAGS*]
+ Update map entry for a given *KEY*.
+
+ *UPDATE_FLAGS* can be one of: **any** update existing entry
+ or add if doesn't exit; **exist** update only if entry already
+ exists; **noexist** update only if entry doesn't exist.
+
+ If the **hex** keyword is provided in front of the bytes
+ sequence, the bytes are parsed as hexadecimal values, even if
+ no "0x" prefix is added. If the keyword is not provided, then
+ the bytes are parsed as decimal values, unless a "0x" prefix
+ (for hexadecimal) or a "0" prefix (for octal) is provided.
+
+ **bpftool map lookup** *MAP* [**key** *DATA*]
+ Lookup **key** in the map.
+
+ **bpftool map getnext** *MAP* [**key** *DATA*]
+ Get next key. If *key* is not specified, get first key.
+
+ **bpftool map delete** *MAP* **key** *DATA*
+ Remove entry from the map.
+
+ **bpftool map pin** *MAP* *FILE*
+ Pin map *MAP* as *FILE*.
+
+ Note: *FILE* must be located in *bpffs* mount. It must not
+ contain a dot character ('.'), which is reserved for future
+ extensions of *bpffs*.
+
+ **bpftool** **map event_pipe** *MAP* [**cpu** *N* **index** *M*]
+ Read events from a **BPF_MAP_TYPE_PERF_EVENT_ARRAY** map.
+
+ Install perf rings into a perf event array map and dump
+ output of any **bpf_perf_event_output**\ () call in the kernel.
+ By default read the number of CPUs on the system and
+ install perf ring for each CPU in the corresponding index
+ in the array.
+
+ If **cpu** and **index** are specified, install perf ring
+ for given **cpu** at **index** in the array (single ring).
+
+ Note that installing a perf ring into an array will silently
+ replace any existing ring. Any other application will stop
+ receiving events if it installed its rings earlier.
+
+ **bpftool map peek** *MAP*
+ Peek next value in the queue or stack.
+
+ **bpftool map push** *MAP* **value** *VALUE*
+ Push *VALUE* onto the stack.
+
+ **bpftool map pop** *MAP*
+ Pop and print value from the stack.
+
+ **bpftool map enqueue** *MAP* **value** *VALUE*
+ Enqueue *VALUE* into the queue.
+
+ **bpftool map dequeue** *MAP*
+ Dequeue and print value from the queue.
+
+ **bpftool map freeze** *MAP*
+ Freeze the map as read-only from user space. Entries from a
+ frozen map can not longer be updated or deleted with the
+ **bpf**\ () system call. This operation is not reversible,
+ and the map remains immutable from user space until its
+ destruction. However, read and write permissions for BPF
+ programs to the map remain unchanged.
+
+ **bpftool map help**
+ Print short help message.
+
+OPTIONS
+=======
+ .. include:: common_options.rst
+
+ -f, --bpffs
+ Show file names of pinned maps.
+
+ -n, --nomount
+ Do not automatically attempt to mount any virtual file system
+ (such as tracefs or BPF virtual file system) when necessary.
+
+EXAMPLES
+========
+**# bpftool map show**
+
+::
+
+ 10: hash name some_map flags 0x0
+ key 4B value 8B max_entries 2048 memlock 167936B
+ pids systemd(1)
+
+The following three commands are equivalent:
+
+|
+| **# bpftool map update id 10 key hex 20 c4 b7 00 value hex 0f ff ff ab 01 02 03 4c**
+| **# bpftool map update id 10 key 0x20 0xc4 0xb7 0x00 value 0x0f 0xff 0xff 0xab 0x01 0x02 0x03 0x4c**
+| **# bpftool map update id 10 key 32 196 183 0 value 15 255 255 171 1 2 3 76**
+
+**# bpftool map lookup id 10 key 0 1 2 3**
+
+::
+
+ key: 00 01 02 03 value: 00 01 02 03 04 05 06 07
+
+
+**# bpftool map dump id 10**
+
+::
+
+ key: 00 01 02 03 value: 00 01 02 03 04 05 06 07
+ key: 0d 00 07 00 value: 02 00 00 00 01 02 03 04
+ Found 2 elements
+
+**# bpftool map getnext id 10 key 0 1 2 3**
+
+::
+
+ key:
+ 00 01 02 03
+ next key:
+ 0d 00 07 00
+
+|
+| **# mount -t bpf none /sys/fs/bpf/**
+| **# bpftool map pin id 10 /sys/fs/bpf/map**
+| **# bpftool map del pinned /sys/fs/bpf/map key 13 00 07 00**
+
+Note that map update can also be used in order to change the program references
+hold by a program array map. This can be used, for example, to change the
+programs used for tail-call jumps at runtime, without having to reload the
+entry-point program. Below is an example for this use case: we load a program
+defining a prog array map, and with a main function that contains a tail call
+to other programs that can be used either to "process" packets or to "debug"
+processing. Note that the prog array map MUST be pinned into the BPF virtual
+file system for the map update to work successfully, as kernel flushes prog
+array maps when they have no more references from user space (and the update
+would be lost as soon as bpftool exits).
+
+|
+| **# bpftool prog loadall tail_calls.o /sys/fs/bpf/foo type xdp**
+| **# bpftool prog --bpffs**
+
+::
+
+ 545: xdp name main_func tag 674b4b5597193dc3 gpl
+ loaded_at 2018-12-12T15:02:58+0000 uid 0
+ xlated 240B jited 257B memlock 4096B map_ids 294
+ pinned /sys/fs/bpf/foo/xdp
+ 546: xdp name bpf_func_process tag e369a529024751fc gpl
+ loaded_at 2018-12-12T15:02:58+0000 uid 0
+ xlated 200B jited 164B memlock 4096B
+ pinned /sys/fs/bpf/foo/process
+ 547: xdp name bpf_func_debug tag 0b597868bc7f0976 gpl
+ loaded_at 2018-12-12T15:02:58+0000 uid 0
+ xlated 200B jited 164B memlock 4096B
+ pinned /sys/fs/bpf/foo/debug
+
+**# bpftool map**
+
+::
+
+ 294: prog_array name jmp_table flags 0x0
+ key 4B value 4B max_entries 1 memlock 4096B
+ owner_prog_type xdp owner jited
+
+|
+| **# bpftool map pin id 294 /sys/fs/bpf/bar**
+| **# bpftool map dump pinned /sys/fs/bpf/bar**
+
+::
+
+ Found 0 elements
+
+|
+| **# bpftool map update pinned /sys/fs/bpf/bar key 0 0 0 0 value pinned /sys/fs/bpf/foo/debug**
+| **# bpftool map dump pinned /sys/fs/bpf/bar**
+
+::
+
+ key: 00 00 00 00 value: 22 02 00 00
+ Found 1 element