1 .. SPDX-License-Identifier: (GPL-2.0-only OR B <<
2 <<
3 =============== 1 ===============
4 bpftool-feature 2 bpftool-feature
5 =============== 3 ===============
6 ---------------------------------------------- 4 -------------------------------------------------------------------------------
7 tool for inspection of eBPF-related parameters 5 tool for inspection of eBPF-related parameters for Linux kernel or net device
8 ---------------------------------------------- 6 -------------------------------------------------------------------------------
9 7
10 :Manual section: 8 8 :Manual section: 8
11 9
12 .. include:: substitutions.rst <<
13 <<
14 SYNOPSIS 10 SYNOPSIS
15 ======== 11 ========
16 12
17 **bpftool** [*OPTIONS*] **feature** *COMMAND* !! 13 **bpftool** [*OPTIONS*] **feature** *COMMAND*
18 14
19 *OPTIONS* := { |COMMON_OPTIONS| } !! 15 *OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] }
20 16
21 *COMMANDS* := { **probe** | **help** } !! 17 *COMMANDS* := { **probe** | **help** }
22 18
23 FEATURE COMMANDS 19 FEATURE COMMANDS
24 ================ 20 ================
25 21
26 | **bpftool** **feature probe** [*COMPONENT*] !! 22 | **bpftool** **feature probe** [*COMPONENT*] [**macros** [**prefix** *PREFIX*]]
27 | **bpftool** **feature list_builtins** *GROUP !! 23 | **bpftool** **feature help**
28 | **bpftool** **feature help** <<
29 | 24 |
30 | *COMPONENT* := { **kernel** | **dev** *NAME* !! 25 | *COMPONENT* := { **kernel** | **dev** *NAME* }
31 | *GROUP* := { **prog_types** | **map_types** <<
32 26
33 DESCRIPTION 27 DESCRIPTION
34 =========== 28 ===========
35 bpftool feature probe [kernel] [full] [macros !! 29 **bpftool feature probe** [**kernel**] [**macros** [**prefix** *PREFIX*]]
36 Probe the running kernel and dump a number !! 30 Probe the running kernel and dump a number of eBPF-related
37 as availability of the **bpf**\ () system !! 31 parameters, such as availability of the **bpf()** system call,
38 types availability, eBPF helper functions !! 32 JIT status, eBPF program types availability, eBPF helper
39 !! 33 functions availability, and more.
40 By default, bpftool **does not run probes* !! 34
41 () and **bpf_trace_printk**\() helpers whi !! 35 If the **macros** keyword (but not the **-j** option) is
42 To enable them and run all probes, the **f !! 36 passed, a subset of the output is dumped as a list of
43 !! 37 **#define** macros that are ready to be included in a C
44 If the **macros** keyword (but not the **- !! 38 header file, for example. If, additionally, **prefix** is
45 of the output is dumped as a list of **#de !! 39 used to define a *PREFIX*, the provided string will be used
46 be included in a C header file, for exampl !! 40 as a prefix to the names of the macros: this can be used to
47 is used to define a *PREFIX*, the provided !! 41 avoid conflicts on macro names when including the output of
48 to the names of the macros: this can be us !! 42 this command as a header file.
49 names when including the output of this co !! 43
50 !! 44 Keyword **kernel** can be omitted. If no probe target is
51 Keyword **kernel** can be omitted. If no p !! 45 specified, probing the kernel is the default behaviour.
52 the kernel is the default behaviour. !! 46
53 !! 47 Note that when probed, some eBPF helpers (e.g.
54 When the **unprivileged** keyword is used, !! 48 **bpf_trace_printk**\ () or **bpf_probe_write_user**\ ()) may
55 features available to a user who does not !! 49 print warnings to kernel logs.
56 capability set. The features available in !! 50
57 small subset of the parameters supported b !! 51 **bpftool feature probe dev** *NAME* [**macros** [**prefix** *PREFIX*]]
58 MUST use the **unprivileged** keyword: Thi !! 52 Probe network device for supported eBPF features and dump
59 bpftool is inadvertently run as non-root, !! 53 results to the console.
60 unavailable if bpftool was compiled withou <<
61 <<
62 bpftool feature probe dev *NAME* [full] [macro <<
63 Probe network device for supported eBPF fe <<
64 console. <<
65 <<
66 The keywords **full**, **macros** and **pr <<
67 probing the kernel. <<
68 <<
69 bpftool feature list_builtins *GROUP* <<
70 List items known to bpftool. These can be <<
71 (**prog_types**), BPF map types (**map_typ <<
72 (**attach_types**), link types (**link_typ <<
73 (**helpers**). The command does not probe <<
74 elements that bpftool knows from compilati <<
75 (for all object types) or from the BPF UAP <<
76 can be used in scripts to iterate over BPF <<
77 54
78 bpftool feature help !! 55 The two keywords **macros** and **prefix** have the same
79 Print short help message. !! 56 role as when probing the kernel.
>> 57
>> 58 **bpftool feature help**
>> 59 Print short help message.
80 60
81 OPTIONS 61 OPTIONS
82 ======= 62 =======
83 .. include:: common_options.rst !! 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 SEE ALSO
>> 77 ========
>> 78 **bpf**\ (2),
>> 79 **bpf-helpers**\ (7),
>> 80 **bpftool**\ (8),
>> 81 **bpftool-prog**\ (8),
>> 82 **bpftool-map**\ (8),
>> 83 **bpftool-cgroup**\ (8),
>> 84 **bpftool-net**\ (8),
>> 85 **bpftool-perf**\ (8)
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