================
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bpftool-map
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================
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-------------------------------------------------------------------------------
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tool for inspection and simple manipulation of eBPF maps
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-------------------------------------------------------------------------------
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:Manual section: 8
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SYNOPSIS
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========
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**bpftool** [*OPTIONS*] **map** *COMMAND*
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*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-f** | **--bpffs** } }
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*COMMANDS* :=
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{ **show** | **list** | **dump** | **update** | **lookup** | **getnext** | **delete**
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| **pin** | **help** }
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MAP COMMANDS
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=============
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| **bpftool** **map { show | list }** [*MAP*]
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| **bpftool** **map dump** *MAP*
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| **bpftool** **map update** *MAP* **key** *DATA* **value** *VALUE* [*UPDATE_FLAGS*]
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| **bpftool** **map lookup** *MAP* **key** *DATA*
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| **bpftool** **map getnext** *MAP* [**key** *DATA*]
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| **bpftool** **map delete** *MAP* **key** *DATA*
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| **bpftool** **map pin** *MAP* *FILE*
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| **bpftool** **map event_pipe** *MAP* [**cpu** *N* **index** *M*]
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| **bpftool** **map help**
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| *MAP* := { **id** *MAP_ID* | **pinned** *FILE* }
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| *DATA* := { [**hex**] *BYTES* }
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| *PROG* := { **id** *PROG_ID* | **pinned** *FILE* | **tag** *PROG_TAG* }
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| *VALUE* := { *DATA* | *MAP* | *PROG* }
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| *UPDATE_FLAGS* := { **any** | **exist** | **noexist** }
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DESCRIPTION
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===========
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**bpftool map { show | list }** [*MAP*]
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Show information about loaded maps. If *MAP* is specified
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show information only about given map, otherwise list all
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maps currently loaded on the system.
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Output will start with map ID followed by map type and
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zero or more named attributes (depending on kernel version).
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**bpftool map dump** *MAP*
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Dump all entries in a given *MAP*.
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**bpftool map update** *MAP* **key** *DATA* **value** *VALUE* [*UPDATE_FLAGS*]
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Update map entry for a given *KEY*.
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*UPDATE_FLAGS* can be one of: **any** update existing entry
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or add if doesn't exit; **exist** update only if entry already
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exists; **noexist** update only if entry doesn't exist.
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If the **hex** keyword is provided in front of the bytes
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sequence, the bytes are parsed as hexadeximal values, even if
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no "0x" prefix is added. If the keyword is not provided, then
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the bytes are parsed as decimal values, unless a "0x" prefix
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(for hexadecimal) or a "0" prefix (for octal) is provided.
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**bpftool map lookup** *MAP* **key** *DATA*
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Lookup **key** in the map.
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**bpftool map getnext** *MAP* [**key** *DATA*]
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Get next key. If *key* is not specified, get first key.
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**bpftool map delete** *MAP* **key** *DATA*
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Remove entry from the map.
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**bpftool map pin** *MAP* *FILE*
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Pin map *MAP* as *FILE*.
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Note: *FILE* must be located in *bpffs* mount.
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**bpftool** **map event_pipe** *MAP* [**cpu** *N* **index** *M*]
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Read events from a BPF_MAP_TYPE_PERF_EVENT_ARRAY map.
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Install perf rings into a perf event array map and dump
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output of any bpf_perf_event_output() call in the kernel.
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By default read the number of CPUs on the system and
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install perf ring for each CPU in the corresponding index
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in the array.
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If **cpu** and **index** are specified, install perf ring
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for given **cpu** at **index** in the array (single ring).
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Note that installing a perf ring into an array will silently
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replace any existing ring. Any other application will stop
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receiving events if it installed its rings earlier.
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**bpftool map help**
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Print short help message.
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OPTIONS
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=======
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-h, --help
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Print short generic help message (similar to **bpftool help**).
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-v, --version
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Print version number (similar to **bpftool version**).
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-j, --json
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Generate JSON output. For commands that cannot produce JSON, this
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option has no effect.
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-p, --pretty
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Generate human-readable JSON output. Implies **-j**.
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-f, --bpffs
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Show file names of pinned maps.
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EXAMPLES
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========
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**# bpftool map show**
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::
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10: hash name some_map flags 0x0
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key 4B value 8B max_entries 2048 memlock 167936B
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The following three commands are equivalent:
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| **# bpftool map update id 10 key hex 20 c4 b7 00 value hex 0f ff ff ab 01 02 03 4c**
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| **# bpftool map update id 10 key 0x20 0xc4 0xb7 0x00 value 0x0f 0xff 0xff 0xab 0x01 0x02 0x03 0x4c**
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| **# bpftool map update id 10 key 32 196 183 0 value 15 255 255 171 1 2 3 76**
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**# bpftool map lookup id 10 key 0 1 2 3**
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::
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key: 00 01 02 03 value: 00 01 02 03 04 05 06 07
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**# bpftool map dump id 10**
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::
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key: 00 01 02 03 value: 00 01 02 03 04 05 06 07
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key: 0d 00 07 00 value: 02 00 00 00 01 02 03 04
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Found 2 elements
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**# bpftool map getnext id 10 key 0 1 2 3**
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::
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key:
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00 01 02 03
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next key:
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0d 00 07 00
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| **# mount -t bpf none /sys/fs/bpf/**
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| **# bpftool map pin id 10 /sys/fs/bpf/map**
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| **# bpftool map del pinned /sys/fs/bpf/map key 13 00 07 00**
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SEE ALSO
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========
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**bpftool**\ (8), **bpftool-prog**\ (8), **bpftool-cgroup**\ (8)
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