Provided by: linux-tools-common_5.19.0-21.21_all bug

NAME

       bpftool-map - tool for inspection and simple manipulation of eBPF maps

SYNOPSIS

          bpftool [OPTIONS] map COMMAND

          OPTIONS := { { -j | --json } [{ -p | --pretty }] | { -d | --debug } | { -l | --legacy }
          | { -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]
         [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 }

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] [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 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

          -h, --help
                 Print short help message (similar to bpftool help).

          -V, --version
                 Print bpftool's version number (similar to bpftool version), the number  of  the
                 libbpf version in use, and optional features that were included when bpftool was
                 compiled. Optional features  include  linking  against  libbfd  to  provide  the
                 disassembler  for  JIT-ted  programs  (bpftool prog dump jited) and usage of BPF
                 skeletons (some features like bpftool prog profile or showing pids associated to
                 BPF objects may rely on it).

          -j, --json
                 Generate  JSON output. For commands that cannot produce JSON, this option has no
                 effect.

          -p, --pretty
                 Generate human-readable JSON output. Implies -j.

          -d, --debug
                 Print all logs available, even debug-level information. This includes logs  from
                 libbpf as well as from the verifier, when attempting to load programs.

          -l, --legacy
                 Use  legacy  libbpf  mode  which  has  more relaxed BPF program requirements. By
                 default, bpftool has more  strict  requirements  about  section  names,  changes
                 pinning logic and doesn't support some of the older non-BTF map declarations.

                 See https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0 for details.

          -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

SEE ALSO

          bpf(2),     bpf-helpers(7),     bpftool(8),     bpftool-btf(8),      bpftool-cgroup(8),
          bpftool-feature(8),  bpftool-gen(8),  bpftool-iter(8), bpftool-link(8), bpftool-net(8),
          bpftool-perf(8), bpftool-prog(8), bpftool-struct_ops(8)

                                                                                   BPFTOOL-MAP(8)