Loading...
1.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2
3===============
4bpftool-feature
5===============
6-------------------------------------------------------------------------------
7tool for inspection of eBPF-related parameters for Linux kernel or net device
8-------------------------------------------------------------------------------
9
10:Manual section: 8
11
12.. include:: substitutions.rst
13
14SYNOPSIS
15========
16
17 **bpftool** [*OPTIONS*] **feature** *COMMAND*
18
19 *OPTIONS* := { |COMMON_OPTIONS| }
20
21 *COMMANDS* := { **probe** | **help** }
22
23FEATURE COMMANDS
24================
25
26| **bpftool** **feature probe** [*COMPONENT*] [**full**] [**unprivileged**] [**macros** [**prefix** *PREFIX*]]
27| **bpftool** **feature list_builtins** *GROUP*
28| **bpftool** **feature help**
29|
30| *COMPONENT* := { **kernel** | **dev** *NAME* }
31| *GROUP* := { **prog_types** | **map_types** | **attach_types** | **link_types** | **helpers** }
32
33DESCRIPTION
34===========
35 **bpftool feature probe** [**kernel**] [**full**] [**macros** [**prefix** *PREFIX*]]
36 Probe the running kernel and dump a number of eBPF-related
37 parameters, such as availability of the **bpf**\ () system call,
38 JIT status, eBPF program types availability, eBPF helper
39 functions availability, and more.
40
41 By default, bpftool **does not run probes** for
42 **bpf_probe_write_user**\ () and **bpf_trace_printk**\()
43 helpers which print warnings to kernel logs. To enable them
44 and run all probes, the **full** keyword should be used.
45
46 If the **macros** keyword (but not the **-j** option) is
47 passed, a subset of the output is dumped as a list of
48 **#define** macros that are ready to be included in a C
49 header file, for example. If, additionally, **prefix** is
50 used to define a *PREFIX*, the provided string will be used
51 as a prefix to the names of the macros: this can be used to
52 avoid conflicts on macro names when including the output of
53 this command as a header file.
54
55 Keyword **kernel** can be omitted. If no probe target is
56 specified, probing the kernel is the default behaviour.
57
58 When the **unprivileged** keyword is used, bpftool will dump
59 only the features available to a user who does not have the
60 **CAP_SYS_ADMIN** capability set. The features available in
61 that case usually represent a small subset of the parameters
62 supported by the system. Unprivileged users MUST use the
63 **unprivileged** keyword: This is to avoid misdetection if
64 bpftool is inadvertently run as non-root, for example. This
65 keyword is unavailable if bpftool was compiled without
66 libcap.
67
68 **bpftool feature probe dev** *NAME* [**full**] [**macros** [**prefix** *PREFIX*]]
69 Probe network device for supported eBPF features and dump
70 results to the console.
71
72 The keywords **full**, **macros** and **prefix** have the
73 same role as when probing the kernel.
74
75 **bpftool feature list_builtins** *GROUP*
76 List items known to bpftool. These can be BPF program types
77 (**prog_types**), BPF map types (**map_types**), attach types
78 (**attach_types**), link types (**link_types**), or BPF helper
79 functions (**helpers**). The command does not probe the system, but
80 simply lists the elements that bpftool knows from compilation time,
81 as provided from libbpf (for all object types) or from the BPF UAPI
82 header (list of helpers). This can be used in scripts to iterate over
83 BPF types or helpers.
84
85 **bpftool feature help**
86 Print short help message.
87
88OPTIONS
89=======
90 .. include:: common_options.rst
1===============
2bpftool-feature
3===============
4-------------------------------------------------------------------------------
5tool for inspection of eBPF-related parameters for Linux kernel or net device
6-------------------------------------------------------------------------------
7
8:Manual section: 8
9
10SYNOPSIS
11========
12
13 **bpftool** [*OPTIONS*] **feature** *COMMAND*
14
15 *OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] }
16
17 *COMMANDS* := { **probe** | **help** }
18
19FEATURE COMMANDS
20================
21
22| **bpftool** **feature probe** [*COMPONENT*] [**macros** [**prefix** *PREFIX*]]
23| **bpftool** **feature help**
24|
25| *COMPONENT* := { **kernel** | **dev** *NAME* }
26
27DESCRIPTION
28===========
29 **bpftool feature probe** [**kernel**] [**macros** [**prefix** *PREFIX*]]
30 Probe the running kernel and dump a number of eBPF-related
31 parameters, such as availability of the **bpf()** system call,
32 JIT status, eBPF program types availability, eBPF helper
33 functions availability, and more.
34
35 If the **macros** keyword (but not the **-j** option) is
36 passed, a subset of the output is dumped as a list of
37 **#define** macros that are ready to be included in a C
38 header file, for example. If, additionally, **prefix** is
39 used to define a *PREFIX*, the provided string will be used
40 as a prefix to the names of the macros: this can be used to
41 avoid conflicts on macro names when including the output of
42 this command as a header file.
43
44 Keyword **kernel** can be omitted. If no probe target is
45 specified, probing the kernel is the default behaviour.
46
47 Note that when probed, some eBPF helpers (e.g.
48 **bpf_trace_printk**\ () or **bpf_probe_write_user**\ ()) may
49 print warnings to kernel logs.
50
51 **bpftool feature probe dev** *NAME* [**macros** [**prefix** *PREFIX*]]
52 Probe network device for supported eBPF features and dump
53 results to the console.
54
55 The two keywords **macros** and **prefix** have the same
56 role as when probing the kernel.
57
58 **bpftool feature help**
59 Print short help message.
60
61OPTIONS
62=======
63 -h, --help
64 Print short generic help message (similar to **bpftool help**).
65
66 -V, --version
67 Print version number (similar to **bpftool version**).
68
69 -j, --json
70 Generate JSON output. For commands that cannot produce JSON, this
71 option has no effect.
72
73 -p, --pretty
74 Generate human-readable JSON output. Implies **-j**.
75
76 -d, --debug
77 Print all logs available from libbpf, including debug-level
78 information.
79
80SEE ALSO
81========
82 **bpf**\ (2),
83 **bpf-helpers**\ (7),
84 **bpftool**\ (8),
85 **bpftool-prog**\ (8),
86 **bpftool-map**\ (8),
87 **bpftool-cgroup**\ (8),
88 **bpftool-net**\ (8),
89 **bpftool-perf**\ (8),
90 **bpftool-btf**\ (8)