NAME

       bpftool-feature  -  tool for inspection of eBPF-related parameters for Linux kernel or net
       device

SYNOPSIS

          bpftool [OPTIONS] feature COMMAND

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

          COMMANDS := { probe | help }

FEATURE COMMANDS

       bpftool feature probe [COMPONENT] [full] [unprivileged] [macros [prefix PREFIX]]
       bpftool feature help

       COMPONENT := { kernel | dev NAME }

DESCRIPTION

          bpftool feature probe [kernel] [full] [macros [prefix PREFIX]]
                 Probe  the  running kernel and dump a number of eBPF-related parameters, such as
                 availability  of  the  bpf()  system  call,  JIT  status,  eBPF  program   types
                 availability, eBPF helper functions availability, and more.

                 By   default,  bpftool  does  not  run  probes  for  bpf_probe_write_user()  and
                 bpf_trace_printk() helpers which print warnings to kernel logs. To  enable  them
                 and run all probes, the full keyword should be used.

                 If  the macros keyword (but not the -j option) is passed, a subset of the output
                 is dumped as a list of #define macros that are ready  to  be  included  in  a  C
                 header  file,  for example. If, additionally, prefix is used to define a PREFIX,
                 the provided string will be used as a prefix to the names of  the  macros:  this
                 can  be used to avoid conflicts on macro names when including the output of this
                 command as a header file.

                 Keyword kernel can be omitted. If no probe  target  is  specified,  probing  the
                 kernel is the default behaviour.

                 When  the  unprivileged  keyword  is  used,  bpftool will dump only the features
                 available to a user who does not have  the  CAP_SYS_ADMIN  capability  set.  The
                 features  available  in  that  case  usually  represent  a  small  subset of the
                 parameters supported by the system. Unprivileged users MUST use the unprivileged
                 keyword:  This  is  to  avoid  misdetection  if  bpftool is inadvertently run as
                 non-root, for example. This keyword  is  unavailable  if  bpftool  was  compiled
                 without libcap.

          bpftool feature probe dev NAME [full] [macros [prefix PREFIX]]
                 Probe  network  device  for  supported  eBPF  features  and  dump results to the
                 console.

                 The keywords full, macros and prefix have the same  role  as  when  probing  the
                 kernel.

          bpftool feature 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.

SEE ALSO

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

                                                                               BPFTOOL-FEATURE(8)