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