diff options
Diffstat (limited to 'tools/bpf/bpftool/Documentation/bpftool-map.rst')
| -rw-r--r-- | tools/bpf/bpftool/Documentation/bpftool-map.rst | 87 |
1 files changed, 83 insertions, 4 deletions
diff --git a/tools/bpf/bpftool/Documentation/bpftool-map.rst b/tools/bpf/bpftool/Documentation/bpftool-map.rst index a6258bc8ec4f..64b001b4f777 100644 --- a/tools/bpf/bpftool/Documentation/bpftool-map.rst +++ b/tools/bpf/bpftool/Documentation/bpftool-map.rst @@ -15,13 +15,15 @@ SYNOPSIS *OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-f** | **--bpffs** } } *COMMANDS* := - { **show** | **list** | **dump** | **update** | **lookup** | **getnext** | **delete** - | **pin** | **help** } + { **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*] [**dev** *NAME*] | **bpftool** **map dump** *MAP* | **bpftool** **map update** *MAP* **key** *DATA* **value** *VALUE* [*UPDATE_FLAGS*] | **bpftool** **map lookup** *MAP* **key** *DATA* @@ -36,6 +38,12 @@ MAP COMMANDS | *PROG* := { **id** *PROG_ID* | **pinned** *FILE* | **tag** *PROG_TAG* } | *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** | **sockmap** | **cpumap** | **xskmap** | **sockhash** +| | **cgroup_storage** | **reuseport_sockarray** | **percpu_cgroup_storage** +| | **queue** | **stack** } DESCRIPTION =========== @@ -47,6 +55,10 @@ DESCRIPTION Output will start with map ID followed by map type and zero or more named attributes (depending on kernel version). + **bpftool map create** *FILE* **type** *TYPE* **key** *KEY_SIZE* **value** *VALUE_SIZE* **entries** *MAX_ENTRIES* **name** *NAME* [**flags** *FLAGS*] [**dev** *NAME*] + Create a new map with given parameters and pin it to *bpffs* + as *FILE*. + **bpftool map dump** *MAP* Dump all entries in a given *MAP*. @@ -75,7 +87,9 @@ DESCRIPTION **bpftool map pin** *MAP* *FILE* Pin map *MAP* as *FILE*. - Note: *FILE* must be located in *bpffs* mount. + 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. @@ -114,6 +128,10 @@ OPTIONS -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** @@ -156,6 +174,67 @@ The following three commands are equivalent: | **# 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 ======== - **bpftool**\ (8), **bpftool-prog**\ (8), **bpftool-cgroup**\ (8) + **bpf**\ (2), + **bpf-helpers**\ (7), + **bpftool**\ (8), + **bpftool-prog**\ (8), + **bpftool-cgroup**\ (8), + **bpftool-net**\ (8), + **bpftool-perf**\ (8) |
