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

Description

bpftoolprog{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.

bpftoolprogdumpxlatedPROG[{fileFILE|[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.

bpftoolprogdumpjitedPROG[{fileFILE|[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.

bpftoolprogpinPROGFILE
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.

bpftoolprog{load|loadall}OBJPATH[typeTYPE][map{idxIDX|nameNAME}MAP][{offload_dev|xdpmeta_dev}NAME][pinmapsMAP_DIR][autoattach]
Load bpf program(s) from binary OBJ and pin as PATH. bpftoolprogload pins only the first program
from the OBJ as PATH. bpftoolprogloadall 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_devNAME is specified program will be loaded onto given networking device
(offload). If xdpmeta_devNAME 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 bpftoolprogshow-f, only show in bpftoollinkshow-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.

bpftoolprogattachPROGATTACH_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.

bpftoolprogdetachPROGATTACH_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.

bpftoolprogtracelog
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)).

bpftoolprogrunPROGdata_inFILE[data_outFILE[data_size_outL]][ctx_inFILE[ctx_outFILE[ctx_size_outM]]][repeatN]
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.

bpftoolprogprofilePROG[durationDURATION]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.

bpftoolproghelp
Print short help message.

Examples

#bpftoolprogshow

          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--prettyprogshow

          [{
                  "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"
                      }
                  ]
              }
          ]

       #bpftoolprogdumpxlatedid10file/tmp/t$ls-l/tmp/t

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

       #bpftoolprogdumpjitedtag005a3d2123620c8b

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

       #mount-tbpfnone/sys/fs/bpf/#bpftoolprogpinid10/sys/fs/bpf/prog#bpftoolprogload./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

       #bpftoolprogdumpjitedpinned/sys/fs/bpf/progopcodes

          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

       #bpftoolprogloadxdp1_kern.o/sys/fs/bpf/xdp1typexdpmapnamerxcntid7#bpftoolprogshowpinned/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#bpftoolprogprofileid337duration10cyclesinstructionsllc_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:
       #bpftoolprogtracelog#bpftoolprogload-L-dfile.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

Name

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

Options

-h, --help
Print short help message (similar to bpftoolhelp).

-V, --version
Print bpftool's version number (similar to bpftoolversion), the number of the libbpf version in
use, and optional features that were included when bpftool was compiled. Optional features include
linking against LLVM or libbfd to provide the disassembler for JIT-ted programs (bpftoolprogdumpjited) and usage of BPF skeletons (some features like bpftoolprogprofile or showing pids
associated to BPF objects may rely on it).

-j, --json
Generate JSON output. For commands that cannot produce JSON, this option has no effect.

-p, --pretty
Generate human-readable JSON output. Implies -j.

-d, --debug
Print all logs available, even debug-level information. This includes logs from libbpf as well as
from the verifier, when attempting to load programs.

-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 bpftoolprogtracelog as a way to dump those
messages).

Prog Commands

bpftoolprog { show | list } [PROG]
       bpftoolprogdumpxlatedPROG [{ fileFILE | [opcodes] [linum] [visual] }]
       bpftoolprogdumpjitedPROG [{ fileFILE | [opcodes] [linum] }]
       bpftoolprogpinPROGFILEbpftoolprog { load | loadall } OBJPATH [typeTYPE] [map { idxIDX | nameNAME } MAP] [{ offload_dev | xdpmeta_dev } NAME] [pinmapsMAP_DIR] [autoattach]
       bpftoolprogattachPROGATTACH_TYPE [MAP]
       bpftoolprogdetachPROGATTACH_TYPE [MAP]
       bpftoolprogtracelogbpftoolprogrunPROGdata_inFILE [data_outFILE [data_size_outL]] [ctx_inFILE [ctx_outFILE [ctx_size_outM]]] [repeatN]
       bpftoolprogprofilePROG [durationDURATION] METRICsbpftoolproghelpMAP := { idMAP_ID | pinnedFILE | nameMAP_NAME }
       PROG := { idPROG_ID | pinnedFILE | tagPROG_TAG | namePROG_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/connect_unix |
         cgroup/getpeername4 | cgroup/getpeername6 | cgroup/getpeername_unix |
         cgroup/getsockname4 | cgroup/getsockname6 | cgroup/getsockname_unix |
         cgroup/sendmsg4 | cgroup/sendmsg6 | cgroup/sendmsg_unix |
         cgroup/recvmsg4 | cgroup/recvmsg6 | cgroup/recvmsg_unix | 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
       }

Synopsis

bpftool [OPTIONS] progCOMMANDOPTIONS  :=  {  {  -j  |  --json  }  [{  -p  | --pretty }] | { -d | --debug } | { -f | --bpffs } | { -m |
       --mapcompat } | { -n | --nomount } | { -L | --use-loader } }

       COMMANDS := { show | list | dumpxlated | dumpjited | pin | load | loadall | help }