NAME

       bpftool-iter - tool to create BPF iterators

SYNOPSIS

          bpftool [OPTIONS] iter COMMAND

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

          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 bpftool's version number (similar to bpftool version), the number  of  the
                 libbpf version in use, 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.

          -l, --legacy
                 Use  legacy  libbpf  mode  which  has  more relaxed BPF program requirements. By
                 default, bpftool has more  strict  requirements  about  section  names,  changes
                 pinning logic and doesn't support some of the older non-BTF map declarations.

                 See https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0 for details.

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)