focal (8) bpftool-iter.8.gz

NAME

       bpftool-iter - tool to create BPF iterators

SYNOPSIS

          bpftool [OPTIONS] iter COMMAND

          OPTIONS := { { -j | --json } [{ -p | --pretty }] | { -d | --debug } }

          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

          -h, --help
                 Print short help message (similar to bpftool help).

          -V, --version
                 Print  version  number  (similar  to bpftool version), and optional features that were included
                 when bpftool was compiled. Optional features include linking  against  libbfd  to  provide  the
                 disassembler  for  JIT-ted  programs (bpftool prog dump jited) and usage of BPF skeletons (some
                 features like bpftool prog profile or showing pids associated to BPF objects may rely on it).

          -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.

          -d, --debug
                 Print all logs available, even debug-level information. This includes logs from libbpf as  well
                 as from the verifier, when attempting to load programs.

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

SEE ALSO

          bpf(2),    bpf-helpers(7),    bpftool(8),   bpftool-btf(8),   bpftool-cgroup(8),   bpftool-feature(8),
          bpftool-gen(8), bpftool-link(8),  bpftool-map(8),  bpftool-net(8),  bpftool-perf(8),  bpftool-prog(8),
          bpftool-struct_ops(8)

                                                                                                 BPFTOOL-ITER(8)