84 lines
3.4 KiB
ReStructuredText
84 lines
3.4 KiB
ReStructuredText
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.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
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===============
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bpftool-feature
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===============
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-------------------------------------------------------------------------------
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tool for inspection of eBPF-related parameters for Linux kernel or net device
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-------------------------------------------------------------------------------
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:Manual section: 8
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.. include:: substitutions.rst
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SYNOPSIS
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========
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**bpftool** [*OPTIONS*] **feature** *COMMAND*
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*OPTIONS* := { |COMMON_OPTIONS| }
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*COMMANDS* := { **probe** | **help** }
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FEATURE COMMANDS
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================
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| **bpftool** **feature probe** [*COMPONENT*] [**full**] [**unprivileged**] [**macros** [**prefix** *PREFIX*]]
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| **bpftool** **feature list_builtins** *GROUP*
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| **bpftool** **feature help**
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| *COMPONENT* := { **kernel** | **dev** *NAME* }
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| *GROUP* := { **prog_types** | **map_types** | **attach_types** | **link_types** | **helpers** }
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DESCRIPTION
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===========
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bpftool feature probe [kernel] [full] [macros [prefix *PREFIX*]]
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Probe the running kernel and dump a number of eBPF-related parameters, such
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as availability of the **bpf**\ () system call, JIT status, eBPF program
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types availability, eBPF helper functions availability, and more.
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By default, bpftool **does not run probes** for **bpf_probe_write_user**\
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() and **bpf_trace_printk**\() helpers which print warnings to kernel logs.
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To enable them and run all probes, the **full** keyword should be used.
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If the **macros** keyword (but not the **-j** option) is passed, a subset
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of the output is dumped as a list of **#define** macros that are ready to
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be included in a C header file, for example. If, additionally, **prefix**
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is used to define a *PREFIX*, the provided string will be used as a prefix
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to the names of the macros: this can be used to avoid conflicts on macro
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names when including the output of this command as a header file.
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Keyword **kernel** can be omitted. If no probe target is specified, probing
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the kernel is the default behaviour.
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When the **unprivileged** keyword is used, bpftool will dump only the
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features available to a user who does not have the **CAP_SYS_ADMIN**
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capability set. The features available in that case usually represent a
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small subset of the parameters supported by the system. Unprivileged users
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MUST use the **unprivileged** keyword: This is to avoid misdetection if
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bpftool is inadvertently run as non-root, for example. This keyword is
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unavailable if bpftool was compiled without libcap.
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bpftool feature probe dev *NAME* [full] [macros [prefix *PREFIX*]]
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Probe network device for supported eBPF features and dump results to the
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console.
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The keywords **full**, **macros** and **prefix** have the same role as when
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probing the kernel.
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bpftool feature list_builtins *GROUP*
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List items known to bpftool. These can be BPF program types
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(**prog_types**), BPF map types (**map_types**), attach types
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(**attach_types**), link types (**link_types**), or BPF helper functions
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(**helpers**). The command does not probe the system, but simply lists the
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elements that bpftool knows from compilation time, as provided from libbpf
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(for all object types) or from the BPF UAPI header (list of helpers). This
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can be used in scripts to iterate over BPF types or helpers.
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bpftool feature help
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Print short help message.
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OPTIONS
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=======
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.. include:: common_options.rst
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