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-rw-r--r-- | tools/bpf/bpftool/Documentation/bpftool-iter.rst | 76 |
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diff --git a/tools/bpf/bpftool/Documentation/bpftool-iter.rst b/tools/bpf/bpftool/Documentation/bpftool-iter.rst new file mode 100644 index 000000000..84839d488 --- /dev/null +++ b/tools/bpf/bpftool/Documentation/bpftool-iter.rst @@ -0,0 +1,76 @@ +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) + +============ +bpftool-iter +============ +------------------------------------------------------------------------------- +tool to create BPF iterators +------------------------------------------------------------------------------- + +:Manual section: 8 + +.. include:: substitutions.rst + +SYNOPSIS +======== + + **bpftool** [*OPTIONS*] **iter** *COMMAND* + + *OPTIONS* := { |COMMON_OPTIONS| } + + *COMMANDS* := { **pin** | **help** } + +ITER COMMANDS +=================== + +| **bpftool** **iter pin** *OBJ* *PATH* [**map** *MAP*] +| **bpftool** **iter help** +| +| *OBJ* := /a/file/of/bpf_iter_target.o +| *MAP* := { **id** *MAP_ID* | **pinned** *FILE* } + +DESCRIPTION +=========== + **bpftool iter pin** *OBJ* *PATH* [**map** *MAP*] + A bpf iterator combines a kernel iterating of + particular kernel data (e.g., tasks, bpf_maps, etc.) + and a bpf program called for each kernel data object + (e.g., one task, one bpf_map, etc.). User space can + *read* kernel iterator output through *read()* syscall. + + The *pin* command creates a bpf iterator from *OBJ*, + and pin it to *PATH*. The *PATH* should be located + in *bpffs* mount. It must not contain a dot + character ('.'), which is reserved for future extensions + of *bpffs*. + + Map element bpf iterator requires an additional parameter + *MAP* so bpf program can iterate over map elements for + that map. User can have a bpf program in kernel to run + with each map element, do checking, filtering, aggregation, + etc. without copying data to user space. + + User can then *cat PATH* to see the bpf iterator output. + + **bpftool iter help** + Print short help message. + +OPTIONS +======= + .. include:: common_options.rst + +EXAMPLES +======== +**# bpftool iter pin bpf_iter_netlink.o /sys/fs/bpf/my_netlink** + +:: + + Create a file-based bpf iterator from bpf_iter_netlink.o and pin it + to /sys/fs/bpf/my_netlink + +**# bpftool iter pin bpf_iter_hashmap.o /sys/fs/bpf/my_hashmap map id 20** + +:: + + Create a file-based bpf iterator from bpf_iter_hashmap.o and map with + id 20, and pin it to /sys/fs/bpf/my_hashmap |