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

Provided by: linux-tools-common_6.8.0-53.55_all

NAME

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

SYNOPSIS

          bpftool [OPTIONS] map COMMAND

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

          -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  LLVM  or  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.

          -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