bpftool-iter - tool to create BPF iterators
Contents
Description
bpftooliterpinOBJPATH[mapMAP]
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 catPATH to see the bpf iterator output.
bpftooliterhelp
Print short help message.
Examples
#bpftooliterpinbpf_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
#bpftooliterpinbpf_iter_hashmap.o/sys/fs/bpf/my_hashmapmapid20
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
Iter Commands
bpftooliterpinOBJPATH [mapMAP]
bpftooliterhelpOBJ := /a/file/of/bpf_iter_target.o
MAP := { idMAP_ID | pinnedFILE }
Name
bpftool-iter - tool to create BPF iterators
Options
-h, --help
Print short help message (similar to bpftoolhelp).
-V, --version
Print bpftool's version number (similar to bpftoolversion), the number of the libbpf version in
use, and optional features that were included when bpftool was compiled. Optional features include
linking against LLVM or libbfd to provide the disassembler for JIT-ted programs (bpftoolprogdumpjited) and usage of BPF skeletons (some features like bpftoolprogprofile 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.
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)
Synopsis
bpftool [OPTIONS] iterCOMMANDOPTIONS := { { -j | --json } [{ -p | --pretty }] | { -d | --debug } }
COMMANDS := { pin | help }
