xref: /openbmc/linux/tools/bpf/bpftool/Documentation/bpftool-prog.rst (revision 1ac731c529cd4d6adbce134754b51ff7d822b145)

.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)

================
bpftool-prog
================
-------------------------------------------------------------------------------
tool for inspection and simple manipulation of eBPF progs
-------------------------------------------------------------------------------

:Manual section: 8

.. include:: substitutions.rst

SYNOPSIS
========

	**bpftool** [*OPTIONS*] **prog** *COMMAND*

	*OPTIONS* := { |COMMON_OPTIONS| |
	{ **-f** | **--bpffs** } | { **-m** | **--mapcompat** } | { **-n** | **--nomount** } |
	{ **-L** | **--use-loader** } }

	*COMMANDS* :=
	{ **show** | **list** | **dump xlated** | **dump jited** | **pin** | **load** |
	**loadall** | **help** }

PROG COMMANDS
=============

|	**bpftool** **prog** { **show** | **list** } [*PROG*]
|	**bpftool** **prog dump xlated** *PROG* [{ **file** *FILE* | [**opcodes**] [**linum**] [**visual**] }]
|	**bpftool** **prog dump jited**  *PROG* [{ **file** *FILE* | [**opcodes**] [**linum**] }]
|	**bpftool** **prog pin** *PROG* *FILE*
|	**bpftool** **prog** { **load** | **loadall** } *OBJ* *PATH* [**type** *TYPE*] [**map** { **idx** *IDX* | **name** *NAME* } *MAP*] [{ **offload_dev** | **xdpmeta_dev** } *NAME*] [**pinmaps** *MAP_DIR*] [**autoattach**]
|	**bpftool** **prog attach** *PROG* *ATTACH_TYPE* [*MAP*]
|	**bpftool** **prog detach** *PROG* *ATTACH_TYPE* [*MAP*]
|	**bpftool** **prog tracelog**
|	**bpftool** **prog run** *PROG* **data_in** *FILE* [**data_out** *FILE* [**data_size_out** *L*]] [**ctx_in** *FILE* [**ctx_out** *FILE* [**ctx_size_out** *M*]]] [**repeat** *N*]
|	**bpftool** **prog profile** *PROG* [**duration** *DURATION*] *METRICs*
|	**bpftool** **prog help**
|
|	*MAP* := { **id** *MAP_ID* | **pinned** *FILE* }
|	*PROG* := { **id** *PROG_ID* | **pinned** *FILE* | **tag** *PROG_TAG* | **name** *PROG_NAME* }
|	*TYPE* := {
|		**socket** | **kprobe** | **kretprobe** | **classifier** | **action** |
|		**tracepoint** | **raw_tracepoint** | **xdp** | **perf_event** | **cgroup/skb** |
|		**cgroup/sock** | **cgroup/dev** | **lwt_in** | **lwt_out** | **lwt_xmit** |
|		**lwt_seg6local** | **sockops** | **sk_skb** | **sk_msg** | **lirc_mode2** |
|		**cgroup/bind4** | **cgroup/bind6** | **cgroup/post_bind4** | **cgroup/post_bind6** |
|		**cgroup/connect4** | **cgroup/connect6** | **cgroup/getpeername4** | **cgroup/getpeername6** |
|               **cgroup/getsockname4** | **cgroup/getsockname6** | **cgroup/sendmsg4** | **cgroup/sendmsg6** |
|		**cgroup/recvmsg4** | **cgroup/recvmsg6** | **cgroup/sysctl** |
|		**cgroup/getsockopt** | **cgroup/setsockopt** | **cgroup/sock_release** |
|		**struct_ops** | **fentry** | **fexit** | **freplace** | **sk_lookup**
|	}
|	*ATTACH_TYPE* := {
|		**sk_msg_verdict** | **sk_skb_verdict** | **sk_skb_stream_verdict** |
|		**sk_skb_stream_parser** | **flow_dissector**
|	}
|	*METRICs* := {
|		**cycles** | **instructions** | **l1d_loads** | **llc_misses** |
|		**itlb_misses** | **dtlb_misses**
|	}


DESCRIPTION
===========
	**bpftool prog { show | list }** [*PROG*]
		  Show information about loaded programs.  If *PROG* is
		  specified show information only about given programs,
		  otherwise list all programs currently loaded on the system.
		  In case of **tag** or **name**, *PROG* may match several
		  programs which will all be shown.

		  Output will start with program ID followed by program type and
		  zero or more named attributes (depending on kernel version).

		  Since Linux 5.1 the kernel can collect statistics on BPF
		  programs (such as the total time spent running the program,
		  and the number of times it was run). If available, bpftool
		  shows such statistics. However, the kernel does not collect
		  them by defaults, as it slightly impacts performance on each
		  program run. Activation or deactivation of the feature is
		  performed via the **kernel.bpf_stats_enabled** sysctl knob.

		  Since Linux 5.8 bpftool is able to discover information about
		  processes that hold open file descriptors (FDs) against BPF
		  programs. On such kernels bpftool will automatically emit this
		  information as well.

	**bpftool prog dump xlated** *PROG* [{ **file** *FILE* | [**opcodes**] [**linum**] [**visual**] }]
		  Dump eBPF instructions of the programs from the kernel. By
		  default, eBPF will be disassembled and printed to standard
		  output in human-readable format. In this case, **opcodes**
		  controls if raw opcodes should be printed as well.

		  In case of **tag** or **name**, *PROG* may match several
		  programs which will all be dumped.  However, if **file** or
		  **visual** is specified, *PROG* must match a single program.

		  If **file** is specified, the binary image will instead be
		  written to *FILE*.

		  If **visual** is specified, control flow graph (CFG) will be
		  built instead, and eBPF instructions will be presented with
		  CFG in DOT format, on standard output.

		  If the programs have line_info available, the source line will
		  be displayed.  If **linum** is specified, the filename, line
		  number and line column will also be displayed.

	**bpftool prog dump jited**  *PROG* [{ **file** *FILE* | [**opcodes**] [**linum**] }]
		  Dump jited image (host machine code) of the program.

		  If *FILE* is specified image will be written to a file,
		  otherwise it will be disassembled and printed to stdout.
		  *PROG* must match a single program when **file** is specified.

		  **opcodes** controls if raw opcodes will be printed.

		  If the prog has line_info available, the source line will
		  be displayed.  If **linum** is specified, the filename, line
		  number and line column will also be displayed.

	**bpftool prog pin** *PROG* *FILE*
		  Pin program *PROG* as *FILE*.

		  Note: *FILE* must be located in *bpffs* mount. It must not
		  contain a dot character ('.'), which is reserved for future
		  extensions of *bpffs*.

	**bpftool prog { load | loadall }** *OBJ* *PATH* [**type** *TYPE*] [**map** { **idx** *IDX* | **name** *NAME* } *MAP*] [{ **offload_dev** | **xdpmeta_dev** } *NAME*] [**pinmaps** *MAP_DIR*] [**autoattach**]
		  Load bpf program(s) from binary *OBJ* and pin as *PATH*.
		  **bpftool prog load** pins only the first program from the
		  *OBJ* as *PATH*. **bpftool prog loadall** pins all programs
		  from the *OBJ* under *PATH* directory.
		  **type** is optional, if not specified program type will be
		  inferred from section names.
		  By default bpftool will create new maps as declared in the ELF
		  object being loaded.  **map** parameter allows for the reuse
		  of existing maps.  It can be specified multiple times, each
		  time for a different map.  *IDX* refers to index of the map
		  to be replaced in the ELF file counting from 0, while *NAME*
		  allows to replace a map by name.  *MAP* specifies the map to
		  use, referring to it by **id** or through a **pinned** file.
		  If **offload_dev** *NAME* is specified program will be loaded
		  onto given networking device (offload).
		  If **xdpmeta_dev** *NAME* is specified program will become
		  device-bound without offloading, this facilitates access
		  to XDP metadata.
		  Optional **pinmaps** argument can be provided to pin all
		  maps under *MAP_DIR* directory.

		  If **autoattach** is specified program will be attached
		  before pin. In that case, only the link (representing the
		  program attached to its hook) is pinned, not the program as
		  such, so the path won't show in **bpftool prog show -f**,
		  only show in **bpftool link show -f**. Also, this only works
		  when bpftool (libbpf) is able to infer all necessary
		  information from the object file, in particular, it's not
		  supported for all program types. If a program does not
		  support autoattach, bpftool falls back to regular pinning
		  for that program instead.

		  Note: *PATH* must be located in *bpffs* mount. It must not
		  contain a dot character ('.'), which is reserved for future
		  extensions of *bpffs*.

	**bpftool prog attach** *PROG* *ATTACH_TYPE* [*MAP*]
		  Attach bpf program *PROG* (with type specified by
		  *ATTACH_TYPE*). Most *ATTACH_TYPEs* require a *MAP*
		  parameter, with the exception of *flow_dissector* which is
		  attached to current networking name space.

	**bpftool prog detach** *PROG* *ATTACH_TYPE* [*MAP*]
		  Detach bpf program *PROG* (with type specified by
		  *ATTACH_TYPE*). Most *ATTACH_TYPEs* require a *MAP*
		  parameter, with the exception of *flow_dissector* which is
		  detached from the current networking name space.

	**bpftool prog tracelog**
		  Dump the trace pipe of the system to the console (stdout).
		  Hit <Ctrl+C> to stop printing. BPF programs can write to this
		  trace pipe at runtime with the **bpf_trace_printk**\ () helper.
		  This should be used only for debugging purposes. For
		  streaming data from BPF programs to user space, one can use
		  perf events (see also **bpftool-map**\ (8)).

	**bpftool prog run** *PROG* **data_in** *FILE* [**data_out** *FILE* [**data_size_out** *L*]] [**ctx_in** *FILE* [**ctx_out** *FILE* [**ctx_size_out** *M*]]] [**repeat** *N*]
		  Run BPF program *PROG* in the kernel testing infrastructure
		  for BPF, meaning that the program works on the data and
		  context provided by the user, and not on actual packets or
		  monitored functions etc. Return value and duration for the
		  test run are printed out to the console.

		  Input data is read from the *FILE* passed with **data_in**.
		  If this *FILE* is "**-**", input data is read from standard
		  input. Input context, if any, is read from *FILE* passed with
		  **ctx_in**. Again, "**-**" can be used to read from standard
		  input, but only if standard input is not already in use for
		  input data. If a *FILE* is passed with **data_out**, output
		  data is written to that file. Similarly, output context is
		  written to the *FILE* passed with **ctx_out**. For both
		  output flows, "**-**" can be used to print to the standard
		  output (as plain text, or JSON if relevant option was
		  passed). If output keywords are omitted, output data and
		  context are discarded. Keywords **data_size_out** and
		  **ctx_size_out** are used to pass the size (in bytes) for the
		  output buffers to the kernel, although the default of 32 kB
		  should be more than enough for most cases.

		  Keyword **repeat** is used to indicate the number of
		  consecutive runs to perform. Note that output data and
		  context printed to files correspond to the last of those
		  runs. The duration printed out at the end of the runs is an
		  average over all runs performed by the command.

		  Not all program types support test run. Among those which do,
		  not all of them can take the **ctx_in**/**ctx_out**
		  arguments. bpftool does not perform checks on program types.

	**bpftool prog profile** *PROG* [**duration** *DURATION*] *METRICs*
		  Profile *METRICs* for bpf program *PROG* for *DURATION*
		  seconds or until user hits <Ctrl+C>. *DURATION* is optional.
		  If *DURATION* is not specified, the profiling will run up to
		  **UINT_MAX** seconds.

	**bpftool prog help**
		  Print short help message.

OPTIONS
=======
	.. include:: common_options.rst

	-f, --bpffs
		  When showing BPF programs, show file names of pinned
		  programs.

	-m, --mapcompat
		  Allow loading maps with unknown map definitions.

	-n, --nomount
		  Do not automatically attempt to mount any virtual file system
		  (such as tracefs or BPF virtual file system) when necessary.

	-L, --use-loader
		  Load program as a "loader" program. This is useful to debug
		  the generation of such programs. When this option is in
		  use, bpftool attempts to load the programs from the object
		  file into the kernel, but does not pin them (therefore, the
		  *PATH* must not be provided).

		  When combined with the **-d**\ \|\ **--debug** option,
		  additional debug messages are generated, and the execution
		  of the loader program will use the **bpf_trace_printk**\ ()
		  helper to log each step of loading BTF, creating the maps,
		  and loading the programs (see **bpftool prog tracelog** as
		  a way to dump those messages).

EXAMPLES
========
**# bpftool prog show**

::

    10: xdp  name some_prog  tag 005a3d2123620c8b  gpl run_time_ns 81632 run_cnt 10
            loaded_at 2017-09-29T20:11:00+0000  uid 0
            xlated 528B  jited 370B  memlock 4096B  map_ids 10
            pids systemd(1)

**# bpftool --json --pretty prog show**

::

    [{
            "id": 10,
            "type": "xdp",
            "tag": "005a3d2123620c8b",
            "gpl_compatible": true,
            "run_time_ns": 81632,
            "run_cnt": 10,
            "loaded_at": 1506715860,
            "uid": 0,
            "bytes_xlated": 528,
            "jited": true,
            "bytes_jited": 370,
            "bytes_memlock": 4096,
            "map_ids": [10
            ],
            "pids": [{
                    "pid": 1,
                    "comm": "systemd"
                }
            ]
        }
    ]

|
| **# bpftool prog dump xlated id 10 file /tmp/t**
| **$ ls -l /tmp/t**

::

    -rw------- 1 root root 560 Jul 22 01:42 /tmp/t

**# bpftool prog dump jited tag 005a3d2123620c8b**

::

    0:   push   %rbp
    1:   mov    %rsp,%rbp
    2:   sub    $0x228,%rsp
    3:   sub    $0x28,%rbp
    4:   mov    %rbx,0x0(%rbp)

|
| **# mount -t bpf none /sys/fs/bpf/**
| **# bpftool prog pin id 10 /sys/fs/bpf/prog**
| **# bpftool prog load ./my_prog.o /sys/fs/bpf/prog2**
| **# ls -l /sys/fs/bpf/**

::

    -rw------- 1 root root 0 Jul 22 01:43 prog
    -rw------- 1 root root 0 Jul 22 01:44 prog2

**# bpftool prog dump jited pinned /sys/fs/bpf/prog opcodes**

::

   0:   push   %rbp
        55
   1:   mov    %rsp,%rbp
        48 89 e5
   4:   sub    $0x228,%rsp
        48 81 ec 28 02 00 00
   b:   sub    $0x28,%rbp
        48 83 ed 28
   f:   mov    %rbx,0x0(%rbp)
        48 89 5d 00

|
| **# bpftool prog load xdp1_kern.o /sys/fs/bpf/xdp1 type xdp map name rxcnt id 7**
| **# bpftool prog show pinned /sys/fs/bpf/xdp1**

::

    9: xdp  name xdp_prog1  tag 539ec6ce11b52f98  gpl
            loaded_at 2018-06-25T16:17:31-0700  uid 0
            xlated 488B  jited 336B  memlock 4096B  map_ids 7

**# rm /sys/fs/bpf/xdp1**

|
| **# bpftool prog profile id 337 duration 10 cycles instructions llc_misses**

::

         51397 run_cnt
      40176203 cycles                                                 (83.05%)
      42518139 instructions    #   1.06 insns per cycle               (83.39%)
           123 llc_misses      #   2.89 LLC misses per million insns  (83.15%)

|
| Output below is for the trace logs.
| Run in separate terminals:
| **# bpftool prog tracelog**
| **# bpftool prog load -L -d file.o**

::

    bpftool-620059  [004] d... 2634685.517903: bpf_trace_printk: btf_load size 665 r=5
    bpftool-620059  [004] d... 2634685.517912: bpf_trace_printk: map_create sample_map idx 0 type 2 value_size 4 value_btf_id 0 r=6
    bpftool-620059  [004] d... 2634685.517997: bpf_trace_printk: prog_load sample insn_cnt 13 r=7
    bpftool-620059  [004] d... 2634685.517999: bpf_trace_printk: close(5) = 0