xref: /linux/tools/bpf/bpftool/Documentation/bpftool-map.rst (revision 0c90f2243ec67eeacf9624ae52ab43c734fe0e93)
1================
2bpftool-map
3================
4-------------------------------------------------------------------------------
5tool for inspection and simple manipulation of eBPF maps
6-------------------------------------------------------------------------------
7
8:Manual section: 8
9
10SYNOPSIS
11========
12
13	**bpftool** [*OPTIONS*] **map** *COMMAND*
14
15	*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-f** | **--bpffs** } }
16
17	*COMMANDS* :=
18	{ **show** | **list** | **dump** | **update** | **lookup** | **getnext** | **delete**
19	| **pin** | **help** }
20
21MAP COMMANDS
22=============
23
24|	**bpftool** **map { show | list }**   [*MAP*]
25|	**bpftool** **map dump**    *MAP*
26|	**bpftool** **map update**  *MAP*  **key** [**hex**] *BYTES*   **value** [**hex**] *VALUE* [*UPDATE_FLAGS*]
27|	**bpftool** **map lookup**  *MAP*  **key** [**hex**] *BYTES*
28|	**bpftool** **map getnext** *MAP* [**key** [**hex**] *BYTES*]
29|	**bpftool** **map delete**  *MAP*  **key** [**hex**] *BYTES*
30|	**bpftool** **map pin**     *MAP*  *FILE*
31|	**bpftool** **map help**
32|
33|	*MAP* := { **id** *MAP_ID* | **pinned** *FILE* }
34|	*PROG* := { **id** *PROG_ID* | **pinned** *FILE* | **tag** *PROG_TAG* }
35|	*VALUE* := { *BYTES* | *MAP* | *PROG* }
36|	*UPDATE_FLAGS* := { **any** | **exist** | **noexist** }
37
38DESCRIPTION
39===========
40	**bpftool map { show | list }**   [*MAP*]
41		  Show information about loaded maps.  If *MAP* is specified
42		  show information only about given map, otherwise list all
43		  maps currently loaded on the system.
44
45		  Output will start with map ID followed by map type and
46		  zero or more named attributes (depending on kernel version).
47
48	**bpftool map dump**    *MAP*
49		  Dump all entries in a given *MAP*.
50
51	**bpftool map update**  *MAP*  **key** [**hex**] *BYTES*   **value** [**hex**] *VALUE* [*UPDATE_FLAGS*]
52		  Update map entry for a given *KEY*.
53
54		  *UPDATE_FLAGS* can be one of: **any** update existing entry
55		  or add if doesn't exit; **exist** update only if entry already
56		  exists; **noexist** update only if entry doesn't exist.
57
58		  If the **hex** keyword is provided in front of the bytes
59		  sequence, the bytes are parsed as hexadeximal values, even if
60		  no "0x" prefix is added. If the keyword is not provided, then
61		  the bytes are parsed as decimal values, unless a "0x" prefix
62		  (for hexadecimal) or a "0" prefix (for octal) is provided.
63
64	**bpftool map lookup**  *MAP*  **key** [**hex**] *BYTES*
65		  Lookup **key** in the map.
66
67	**bpftool map getnext** *MAP* [**key** [**hex**] *BYTES*]
68		  Get next key.  If *key* is not specified, get first key.
69
70	**bpftool map delete**  *MAP*  **key** [**hex**] *BYTES*
71		  Remove entry from the map.
72
73	**bpftool map pin**     *MAP*  *FILE*
74		  Pin map *MAP* as *FILE*.
75
76		  Note: *FILE* must be located in *bpffs* mount.
77
78	**bpftool map help**
79		  Print short help message.
80
81OPTIONS
82=======
83	-h, --help
84		  Print short generic help message (similar to **bpftool help**).
85
86	-v, --version
87		  Print version number (similar to **bpftool version**).
88
89	-j, --json
90		  Generate JSON output. For commands that cannot produce JSON, this
91		  option has no effect.
92
93	-p, --pretty
94		  Generate human-readable JSON output. Implies **-j**.
95
96	-f, --bpffs
97		  Show file names of pinned maps.
98
99EXAMPLES
100========
101**# bpftool map show**
102::
103
104  10: hash  name some_map  flags 0x0
105	key 4B  value 8B  max_entries 2048  memlock 167936B
106
107The following three commands are equivalent:
108
109|
110| **# bpftool map update id 10 key hex   20   c4   b7   00 value hex   0f   ff   ff   ab   01   02   03   4c**
111| **# bpftool map update id 10 key     0x20 0xc4 0xb7 0x00 value     0x0f 0xff 0xff 0xab 0x01 0x02 0x03 0x4c**
112| **# bpftool map update id 10 key       32  196  183    0 value       15  255  255  171    1    2    3   76**
113
114**# bpftool map lookup id 10 key 0 1 2 3**
115
116::
117
118  key: 00 01 02 03 value: 00 01 02 03 04 05 06 07
119
120
121**# bpftool map dump id 10**
122::
123
124  key: 00 01 02 03  value: 00 01 02 03 04 05 06 07
125  key: 0d 00 07 00  value: 02 00 00 00 01 02 03 04
126  Found 2 elements
127
128**# bpftool map getnext id 10 key 0 1 2 3**
129::
130
131  key:
132  00 01 02 03
133  next key:
134  0d 00 07 00
135
136|
137| **# mount -t bpf none /sys/fs/bpf/**
138| **# bpftool map pin id 10 /sys/fs/bpf/map**
139| **# bpftool map del pinned /sys/fs/bpf/map key 13 00 07 00**
140
141SEE ALSO
142========
143	**bpftool**\ (8), **bpftool-prog**\ (8), **bpftool-cgroup**\ (8)
144