table of contents
| BPFTOOL-MAP(8) | BPFTOOL-MAP(8) |
NAME¶
bpftool-map - tool for inspection and simple manipulation of eBPF maps
SYNOPSIS¶
OPTIONS := { { -j | --json } [{ -p | --pretty }] | { -f | --bpffs } }
COMMANDS := { show | list | dump | update | lookup | getnext | delete | pin | help }
MAP COMMANDS¶
bpftool map { show | list } [MAP]
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 help
MAP := { id MAP_ID | pinned FILE }
DATA := { [hex] BYTES }
PROG := { id PROG_ID | pinned FILE | tag PROG_TAG }
VALUE := { DATA | MAP | PROG }
UPDATE_FLAGS := { any | exist | noexist }
DESCRIPTION¶
- bpftool map { show | list } [MAP]
- Show information about loaded maps. If MAP is specified show
information only about given map, otherwise list all maps currently loaded
on the system.
Output will start with map ID followed by map type and zero or more named attributes (depending on kernel version).
- bpftool map dump MAP
- Dump all entries in a given MAP.
- 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 hexadeximal 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.
- bpftool map help
- Print short help message.
OPTIONS¶
- -h, --help
- Print short generic help message (similar to bpftool help).
- -v, --version
- Print version number (similar to bpftool version).
- -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.
- -f, --bpffs
- Show file names of pinned maps.
EXAMPLES¶
# bpftool map show
10: hash name some_map flags 0x0
key 4B value 8B max_entries 2048 memlock 167936B
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