Commit graph

172 commits

Author SHA1 Message Date
Daniel T. Lee
151936bf51 samples: bpf: Replace attach_tracepoint() to attach() in xdp_redirect_cpu
>From commit d7a18ea7e8 ("libbpf: Add generic bpf_program__attach()"),
for some BPF programs, it is now possible to attach BPF programs
with __attach() instead of explicitly calling __attach_<type>().

This commit refactors the __attach_tracepoint() with libbpf's generic
__attach() method. In addition, this refactors the logic of setting
the map FD to simplify the code. Also, the missing removal of
bpf_load.o in Makefile has been fixed.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201010181734.1109-3-danieltimlee@gmail.com
2020-10-11 12:14:36 -07:00
Daniel T. Lee
8ac91df6de samples: bpf: Refactor xdp_monitor with libbpf
To avoid confusion caused by the increasing fragmentation of the BPF
Loader program, this commit would like to change to the libbpf loader
instead of using the bpf_load.

Thanks to libbpf's bpf_link interface, managing the tracepoint BPF
program is much easier. bpf_program__attach_tracepoint manages the
enable of tracepoint event and attach of BPF programs to it with a
single interface bpf_link, so there is no need to manage event_fd and
prog_fd separately.

This commit refactors xdp_monitor with using this libbpf API, and the
bpf_load is removed and migrated to libbpf.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201010181734.1109-2-danieltimlee@gmail.com
2020-10-11 12:14:36 -07:00
Yonghong Song
9618bde489 samples/bpf: Change Makefile to cope with latest llvm
With latest llvm trunk, bpf programs under samples/bpf
directory, if using CORE, may experience the following
errors:

LLVM ERROR: Cannot select: intrinsic %llvm.preserve.struct.access.index
PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace.
Stack dump:
0.      Program arguments: llc -march=bpf -filetype=obj -o samples/bpf/test_probe_write_user_kern.o
1.      Running pass 'Function Pass Manager' on module '<stdin>'.
2.      Running pass 'BPF DAG->DAG Pattern Instruction Selection' on function '@bpf_prog1'
 #0 0x000000000183c26c llvm::sys::PrintStackTrace(llvm::raw_ostream&, int)
    (/data/users/yhs/work/llvm-project/llvm/build.cur/install/bin/llc+0x183c26c)
...
 #7 0x00000000017c375e (/data/users/yhs/work/llvm-project/llvm/build.cur/install/bin/llc+0x17c375e)
 #8 0x00000000016a75c5 llvm::SelectionDAGISel::CannotYetSelect(llvm::SDNode*)
    (/data/users/yhs/work/llvm-project/llvm/build.cur/install/bin/llc+0x16a75c5)
 #9 0x00000000016ab4f8 llvm::SelectionDAGISel::SelectCodeCommon(llvm::SDNode*, unsigned char const*,
    unsigned int) (/data/users/yhs/work/llvm-project/llvm/build.cur/install/bin/llc+0x16ab4f8)
...
Aborted (core dumped) | llc -march=bpf -filetype=obj -o samples/bpf/test_probe_write_user_kern.o

The reason is due to llvm change https://reviews.llvm.org/D87153
where the CORE relocation global generation is moved from the beginning
of target dependent optimization (llc) to the beginning
of target independent optimization (opt).

Since samples/bpf programs did not use vmlinux.h and its clang compilation
uses native architecture, we need to adjust arch triple at opt level
to do CORE relocation global generation properly. Otherwise, the above
error will appear.

This patch fixed the issue by introduce opt and llvm-dis to compilation chain,
which will do proper CORE relocation global generation as well as O2 level
optimization. Tested with llvm10, llvm11 and trunk/llvm12.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20201006043427.1891742-1-yhs@fb.com
2020-10-06 11:45:03 -07:00
Cristian Dumitrescu
35149b2c04 samples/bpf: Add new sample xsk_fwd.c
This sample code illustrates the packet forwarding between multiple
AF_XDP sockets in multi-threading environment. All the threads and
sockets are sharing a common buffer pool, with each socket having
its own private buffer cache. The sockets are created with the
xsk_socket__create_shared() function, which allows multiple AF_XDP
sockets to share the same UMEM object.

Example 1: Single thread handling two sockets. Packets received
from socket A (on top of interface IFA, queue QA) are forwarded
to socket B (on top of interface IFB, queue QB) and vice-versa.
The thread is affinitized to CPU core C:

./xsk_fwd -i IFA -q QA -i IFB -q QB -c C

Example 2: Two threads, each handling two sockets. Packets from
socket A are sent to socket B (by thread X), packets
from socket B are sent to socket A (by thread X); packets from
socket C are sent to socket D (by thread Y), packets from socket
D are sent to socket C (by thread Y). The two threads are bound
to CPU cores CX and CY:

./xdp_fwd -i IFA -q QA -i IFB -q QB -i IFC -q QC -i IFD -q QD -c CX -c CY

Signed-off-by: Cristian Dumitrescu <cristian.dumitrescu@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Link: https://lore.kernel.org/bpf/1598603189-32145-15-git-send-email-magnus.karlsson@intel.com
2020-08-31 21:17:55 +02:00
Daniel T. Lee
f0c328f8af samples: bpf: Refactor tracepoint tracing programs with libbpf
For the problem of increasing fragmentation of the bpf loader programs,
instead of using bpf_loader.o, which is used in samples/bpf, this
commit refactors the existing tracepoint tracing programs with libbbpf
bpf loader.

    - Adding a tracepoint event and attaching a bpf program to it was done
    through bpf_program_attach().
    - Instead of using the existing BPF MAP definition, MAP definition
    has been refactored with the new BTF-defined MAP format.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200823085334.9413-4-danieltimlee@gmail.com
2020-08-24 20:59:35 -07:00
Daniel T. Lee
3677d0a131 samples: bpf: Refactor kprobe tracing programs with libbpf
For the problem of increasing fragmentation of the bpf loader programs,
instead of using bpf_loader.o, which is used in samples/bpf, this
commit refactors the existing kprobe tracing programs with libbbpf
bpf loader.

    - For kprobe events pointing to system calls, the SYSCALL() macro in
    trace_common.h was used.
    - Adding a kprobe event and attaching a bpf program to it was done
    through bpf_program_attach().
    - Instead of using the existing BPF MAP definition, MAP definition
    has been refactored with the new BTF-defined MAP format.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200823085334.9413-3-danieltimlee@gmail.com
2020-08-24 20:59:35 -07:00
Daniel T. Lee
35a8b6dd33 samples: bpf: Cleanup bpf_load.o from Makefile
Since commit cc7f641d63 ("samples: bpf: Refactor BPF map performance
test with libbpf") has ommited the removal of bpf_load.o from Makefile,
this commit removes the bpf_load.o rule for targets where bpf_load.o is
not used.

Fixes: cc7f641d63 ("samples: bpf: Refactor BPF map performance test with libbpf")
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200823085334.9413-2-danieltimlee@gmail.com
2020-08-24 20:59:35 -07:00
Daniel T. Lee
88795b4adb samples: bpf: Refactor BPF map in map test with libbpf
From commit 646f02ffdd ("libbpf: Add BTF-defined map-in-map
support"), a way to define internal map in BTF-defined map has been
added.

Instead of using previous 'inner_map_idx' definition, the structure to
be used for the inner map can be directly defined using array directive.

    __array(values, struct inner_map)

This commit refactors map in map test program with libbpf by explicitly
defining inner map with BTF-defined format.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200707184855.30968-3-danieltimlee@gmail.com
2020-07-08 01:33:10 +02:00
Daniel T. Lee
bc1a85977b samples, bpf: Refactor tail call user progs with libbpf
BPF tail call uses the BPF_MAP_TYPE_PROG_ARRAY type map for calling
into other BPF programs and this PROG_ARRAY should be filled prior to
use. Currently, samples with the PROG_ARRAY type MAP fill this program
array with bpf_load. For bpf_load to fill this map, kernel BPF program
must specify the section with specific format of <prog_type>/<array_idx>
(e.g. SEC("socket/0"))

But by using libbpf instead of bpf_load, user program can specify which
programs should be added to PROG_ARRAY. The advantage of this approach
is that you can selectively add only the programs you want, rather than
adding all of them to PROG_ARRAY, and it's much more intuitive than the
traditional approach.

This commit refactors user programs with the PROG_ARRAY type MAP with
libbpf instead of using bpf_load.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200516040608.1377876-4-danieltimlee@gmail.com
2020-05-19 17:12:56 +02:00
Daniel T. Lee
63841bc083 samples, bpf: Refactor kprobe tracing user progs with libbpf
Currently, the kprobe BPF program attachment method for bpf_load is
quite old. The implementation of bpf_load "directly" controls and
manages(create, delete) the kprobe events of DEBUGFS. On the other hand,
using using the libbpf automatically manages the kprobe event.
(under bpf_link interface)

By calling bpf_program__attach(_kprobe) in libbpf, the corresponding
kprobe is created and the BPF program will be attached to this kprobe.
To remove this, by simply invoking bpf_link__destroy will clean up the
event.

This commit refactors kprobe tracing programs (tracex{1~7}_user.c) with
libbpf using bpf_link interface and bpf_program__attach.

tracex2_kern.c, which tracks system calls (sys_*), has been modified to
append prefix depending on architecture.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200516040608.1377876-3-danieltimlee@gmail.com
2020-05-19 17:12:53 +02:00
Daniel T. Lee
aa5e2af660 samples, bpf: Refactor perf_event user program with libbpf bpf_link
The bpf_program__attach of libbpf(using bpf_link) is much more intuitive
than the previous method using ioctl.

bpf_program__attach_perf_event manages the enable of perf_event and
attach of BPF programs to it, so there's no neeed to do this
directly with ioctl.

In addition, bpf_link provides consistency in the use of API because it
allows disable (detach, destroy) for multiple events to be treated as
one bpf_link__destroy. Also, bpf_link__destroy manages the close() of
perf_event fd.

This commit refactors samples that attach the bpf program to perf_event
by using libbbpf instead of ioctl. Also the bpf_load in the samples were
removed and migrated to use libbbpf API.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200321100424.1593964-3-danieltimlee@gmail.com
2020-03-23 22:27:57 +01:00
Daniel T. Lee
24a6034acc samples, bpf: Move read_trace_pipe to trace_helpers
To reduce the reliance of trace samples (trace*_user) on bpf_load,
move read_trace_pipe to trace_helpers. By moving this bpf_loader helper
elsewhere, trace functions can be easily migrated to libbbpf.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200321100424.1593964-2-danieltimlee@gmail.com
2020-03-23 22:27:51 +01:00
Masahiro Yamada
5f2fb52fac kbuild: rename hostprogs-y/always to hostprogs/always-y
In old days, the "host-progs" syntax was used for specifying host
programs. It was renamed to the current "hostprogs-y" in 2004.

It is typically useful in scripts/Makefile because it allows Kbuild to
selectively compile host programs based on the kernel configuration.

This commit renames like follows:

  always       ->  always-y
  hostprogs-y  ->  hostprogs

So, scripts/Makefile will look like this:

  always-$(CONFIG_BUILD_BIN2C) += ...
  always-$(CONFIG_KALLSYMS)    += ...
      ...
  hostprogs := $(always-y) $(always-m)

I think this makes more sense because a host program is always a host
program, irrespective of the kernel configuration. We want to specify
which ones to compile by CONFIG options, so always-y will be handier.

The "always", "hostprogs-y", "hostprogs-m" will be kept for backward
compatibility for a while.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-02-04 01:53:07 +09:00
Toke Høiland-Jørgensen
7cf245a37e samples/bpf: Use consistent include paths for libbpf
Fix all files in samples/bpf to include libbpf header files with the bpf/
prefix, to be consistent with external users of the library. Also ensure
that all includes of exported libbpf header files (those that are exported
on 'make install' of the library) use bracketed includes instead of quoted.

To make sure no new files are introduced that doesn't include the bpf/
prefix in its include, remove tools/lib/bpf from the include path entirely,
and use tools/lib instead.

Fixes: 6910d7d386 ("selftests/bpf: Ensure bpf_helper_defs.h are taken from selftests dir")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/157952560911.1683545.8795966751309534150.stgit@toke.dk
2020-01-20 16:37:45 -08:00
Toke Høiland-Jørgensen
b2e5e93ae8 samples/bpf: Don't try to remove user's homedir on clean
The 'clean' rule in the samples/bpf Makefile tries to remove backup
files (ending in ~). However, if no such files exist, it will instead try
to remove the user's home directory. While the attempt is mostly harmless,
it does lead to a somewhat scary warning like this:

rm: cannot remove '~': Is a directory

Fix this by using find instead of shell expansion to locate any actual
backup files that need to be removed.

Fixes: b62a796c10 ("samples/bpf: allow make to be run from samples/bpf/ directory")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/bpf/157952560126.1683545.7273054725976032511.stgit@toke.dk
2020-01-20 16:37:45 -08:00
Toke Høiland-Jørgensen
450278977a samples/bpf: Set -fno-stack-protector when building BPF programs
It seems Clang can in some cases turn on stack protection by default, which
doesn't work with BPF. This was reported once before[0], but it seems the
flag to explicitly turn off the stack protector wasn't added to the
Makefile, so do that now.

The symptom of this is compile errors like the following:

error: <unknown>:0:0: in function bpf_prog1 i32 (%struct.__sk_buff*): A call to built-in function '__stack_chk_fail' is not supported.

[0] https://www.spinics.net/lists/netdev/msg556400.html

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191216103819.359535-1-toke@redhat.com
2019-12-16 07:03:12 -08:00
Toke Høiland-Jørgensen
5615ed472d samples/bpf: Add missing -lz to TPROGS_LDLIBS
Since libbpf now links against zlib, this needs to be included in the
linker invocation for the userspace programs in samples/bpf that link
statically against libbpf.

Fixes: 166750bc1d ("libbpf: Support libbpf-provided extern variables")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Björn Töpel <bjorn.topel@intel.com>
Link: https://lore.kernel.org/bpf/20191216102405.353834-1-toke@redhat.com
2019-12-16 06:58:10 -08:00
Prashant Bhole
5984dc6cb5 samples/bpf: Reintroduce missed build targets
Add xdp_redirect and per_socket_stats_example in build targets.
They got removed from build targets in Makefile reorganization.

Fixes: 1d97c6c251 ("samples/bpf: Base target programs rules on Makefile.target")
Signed-off-by: Prashant Bhole <prashantbhole.linux@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191216071619.25479-1-prashantbhole.linux@gmail.com
2019-12-16 06:55:30 -08:00
David S. Miller
ee5a489fd9 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:

====================
pull-request: bpf-next 2019-11-20

The following pull-request contains BPF updates for your *net-next* tree.

We've added 81 non-merge commits during the last 17 day(s) which contain
a total of 120 files changed, 4958 insertions(+), 1081 deletions(-).

There are 3 trivial conflicts, resolve it by always taking the chunk from
196e8ca748:

<<<<<<< HEAD
=======
void *bpf_map_area_mmapable_alloc(u64 size, int numa_node);
>>>>>>> 196e8ca748

<<<<<<< HEAD
void *bpf_map_area_alloc(u64 size, int numa_node)
=======
static void *__bpf_map_area_alloc(u64 size, int numa_node, bool mmapable)
>>>>>>> 196e8ca748

<<<<<<< HEAD
        if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {
=======
        /* kmalloc()'ed memory can't be mmap()'ed */
        if (!mmapable && size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {
>>>>>>> 196e8ca748

The main changes are:

1) Addition of BPF trampoline which works as a bridge between kernel functions,
   BPF programs and other BPF programs along with two new use cases: i) fentry/fexit
   BPF programs for tracing with practically zero overhead to call into BPF (as
   opposed to k[ret]probes) and ii) attachment of the former to networking related
   programs to see input/output of networking programs (covering xdpdump use case),
   from Alexei Starovoitov.

2) BPF array map mmap support and use in libbpf for global data maps; also a big
   batch of libbpf improvements, among others, support for reading bitfields in a
   relocatable manner (via libbpf's CO-RE helper API), from Andrii Nakryiko.

3) Extend s390x JIT with usage of relative long jumps and loads in order to lift
   the current 64/512k size limits on JITed BPF programs there, from Ilya Leoshkevich.

4) Add BPF audit support and emit messages upon successful prog load and unload in
   order to have a timeline of events, from Daniel Borkmann and Jiri Olsa.

5) Extension to libbpf and xdpsock sample programs to demo the shared umem mode
   (XDP_SHARED_UMEM) as well as RX-only and TX-only sockets, from Magnus Karlsson.

6) Several follow-up bug fixes for libbpf's auto-pinning code and a new API
   call named bpf_get_link_xdp_info() for retrieving the full set of prog
   IDs attached to XDP, from Toke Høiland-Jørgensen.

7) Add BTF support for array of int, array of struct and multidimensional arrays
   and enable it for skb->cb[] access in kfree_skb test, from Martin KaFai Lau.

8) Fix AF_XDP by using the correct number of channels from ethtool, from Luigi Rizzo.

9) Two fixes for BPF selftest to get rid of a hang in test_tc_tunnel and to avoid
   xdping to be run as standalone, from Jiri Benc.

10) Various BPF selftest fixes when run with latest LLVM trunk, from Yonghong Song.

11) Fix a memory leak in BPF fentry test run data, from Colin Ian King.

12) Various smaller misc cleanups and improvements mostly all over BPF selftests and
    samples, from Daniel T. Lee, Andre Guedes, Anders Roxell, Mao Wenan, Yue Haibing.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2019-11-20 18:11:23 -08:00
Jesper Dangaard Brouer
6cc2c8762d samples/bpf: adjust Makefile and README.rst
Side effect of some kbuild changes resulted in breaking the
documented way to build samples/bpf/.

This patch change the samples/bpf/Makefile to work again, when
invoking make from the subdir samples/bpf/. Also update the
documentation in README.rst, to reflect the new way to build.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-11-11 21:42:09 -08:00
Magnus Karlsson
2e5d72c15f samples/bpf: Add XDP_SHARED_UMEM support to xdpsock
Add support for the XDP_SHARED_UMEM mode to the xdpsock sample
application. As libbpf does not have a built in XDP program for this
mode, we use an explicitly loaded XDP program. This also serves as an
example on how to write your own XDP program that can route to an
AF_XDP socket.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: William Tu <u9012063@gmail.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Link: https://lore.kernel.org/bpf/1573148860-30254-3-git-send-email-magnus.karlsson@intel.com
2019-11-10 19:30:45 -08:00
David S. Miller
14684b9301 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
One conflict in the BPF samples Makefile, some fixes in 'net' whilst
we were converting over to Makefile.target rules in 'net-next'.

Signed-off-by: David S. Miller <davem@davemloft.net>
2019-11-09 11:04:37 -08:00
Björn Töpel
04ec044b7d samples/bpf: fix build by setting HAVE_ATTR_TEST to zero
To remove that test_attr__{enabled/open} are used by perf-sys.h, we
set HAVE_ATTR_TEST to zero.

Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Tested-by: KP Singh <kpsingh@google.com>
Acked-by: Song Liu <songliubraving@fb.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: http://lore.kernel.org/bpf/20191001113307.27796-3-bjorn.topel@gmail.com
2019-10-31 21:39:15 +01:00
Ivan Khoronzhuk
b2327c107d samples/bpf: Add sysroot support
Basically it only enables that was added by previous couple fixes.
Sysroot contains correct libs installed and its headers. Useful when
working with NFC or virtual machine.

Usage example:

clean (on demand)
    make ARCH=arm -C samples/bpf clean
    make ARCH=arm -C tools clean
    make ARCH=arm clean

configure and install headers:

    make ARCH=arm defconfig
    make ARCH=arm headers_install

build samples/bpf:
    make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- samples/bpf/ \
    SYSROOT="path/to/sysroot"

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191011002808.28206-15-ivan.khoronzhuk@linaro.org
2019-10-12 16:08:59 -07:00
Ivan Khoronzhuk
d8ceae91e9 samples/bpf: Provide C/LDFLAGS to libbpf
In order to build lib using C/LD flags of target arch, provide them
to libbpf make.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191011002808.28206-14-ivan.khoronzhuk@linaro.org
2019-10-12 16:08:59 -07:00
Ivan Khoronzhuk
a833effa15 samples/bpf: Use target CC environment for HDR_PROBE
No need in hacking HOSTCC to be cross-compiler any more, so drop
this trick and use target CC for HDR_PROBE.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20191011002808.28206-11-ivan.khoronzhuk@linaro.org
2019-10-12 16:08:59 -07:00
Ivan Khoronzhuk
10cb3d8706 samples/bpf: Use own flags but not HOSTCFLAGS
While compiling natively, the host's cflags and ldflags are equal to
ones used from HOSTCFLAGS and HOSTLDFLAGS. When cross compiling it
should have own, used for target arch. While verification, for arm,
arm64 and x86_64 the following flags were used always:

-Wall -O2
-fomit-frame-pointer
-Wmissing-prototypes
-Wstrict-prototypes

So, add them as they were verified and used before adding
Makefile.target and lets omit "-fomit-frame-pointer" as were proposed
while review, as no sense in such optimization for samples.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191011002808.28206-10-ivan.khoronzhuk@linaro.org
2019-10-12 16:08:59 -07:00
Ivan Khoronzhuk
1d97c6c251 samples/bpf: Base target programs rules on Makefile.target
The main reason for that - HOSTCC and CC have different aims.
HOSTCC is used to build programs running on host, that can
cross-comple target programs with CC. It was tested for arm and arm64
cross compilation, based on linaro toolchain, but should work for
others.

So, in order to split cross compilation (CC) with host build (HOSTCC),
lets base samples on Makefile.target. It allows to cross-compile
samples/bpf programs with CC while auxialry tools running on host
built with HOSTCC.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191011002808.28206-9-ivan.khoronzhuk@linaro.org
2019-10-12 16:08:59 -07:00
Ivan Khoronzhuk
54b7fbd448 samples/bpf: Drop unnecessarily inclusion for bpf_load
Drop inclusion for bpf_load -I$(objtree)/usr/include as it is
included for all objects anyway, with above line:
KBUILD_HOSTCFLAGS += -I$(objtree)/usr/include

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20191011002808.28206-7-ivan.khoronzhuk@linaro.org
2019-10-12 16:08:59 -07:00
Ivan Khoronzhuk
0e865aedad samples/bpf: Use __LINUX_ARM_ARCH__ selector for arm
For arm, -D__LINUX_ARM_ARCH__=X is min version used as instruction
set selector and is absolutely required while parsing some parts of
headers. It's present in KBUILD_CFLAGS but not in autoconf.h, so let's
retrieve it from and add to programs cflags. In another case errors
like "SMP is not supported" for armv7 and bunch of other errors are
issued resulting to incorrect final object.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191011002808.28206-6-ivan.khoronzhuk@linaro.org
2019-10-12 16:08:59 -07:00
Ivan Khoronzhuk
2a560df7c1 samples/bpf: Use own EXTRA_CFLAGS for clang commands
It can overlap with CFLAGS used for libraries built with gcc if
not now then in next patches. Correct it here for simplicity.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20191011002808.28206-5-ivan.khoronzhuk@linaro.org
2019-10-12 16:08:59 -07:00
Ivan Khoronzhuk
518c13401e samples/bpf: Use --target from cross-compile
For cross compiling the target triple can be inherited from
cross-compile prefix as it's done in CLANG_FLAGS from kernel makefile.
So copy-paste this decision from kernel Makefile.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20191011002808.28206-4-ivan.khoronzhuk@linaro.org
2019-10-12 16:08:59 -07:00
Ivan Khoronzhuk
39e0c3649f samples/bpf: Fix cookie_uid_helper_example obj build
Don't list userspace "cookie_uid_helper_example" object in list for
bpf objects.

'always' target is used for listing bpf programs, but
'cookie_uid_helper_example.o' is a user space ELF file, and covered
by rule `per_socket_stats_example`, so shouldn't be in 'always'.
Let us remove `always += cookie_uid_helper_example.o`, which avoids
breaking cross compilation due to mismatched includes.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20191011002808.28206-3-ivan.khoronzhuk@linaro.org
2019-10-12 16:08:59 -07:00
Ivan Khoronzhuk
cdd5b2d1fc samples/bpf: Fix HDR_PROBE "echo"
echo should be replaced with echo -e to handle '\n' correctly, but
instead, replace it with printf as some systems can't handle echo -e.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20191011002808.28206-2-ivan.khoronzhuk@linaro.org
2019-10-12 16:08:58 -07:00
Andrii Nakryiko
e01a75c159 libbpf: Move bpf_{helpers, helper_defs, endian, tracing}.h into libbpf
Move bpf_helpers.h, bpf_tracing.h, and bpf_endian.h into libbpf. Move
bpf_helper_defs.h generation into libbpf's Makefile. Ensure all those
headers are installed along the other libbpf headers. Also, adjust
selftests and samples include path to include libbpf now.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20191008175942.1769476-6-andriin@fb.com
2019-10-08 23:16:03 +02:00
Ilya Leoshkevich
81f522f96f samples/bpf: build with -D__TARGET_ARCH_$(SRCARCH)
While $ARCH can be relatively flexible (see Makefile and
tools/scripts/Makefile.arch), $SRCARCH always corresponds to a directory
name under arch/.

Therefore, build samples with -D__TARGET_ARCH_$(SRCARCH), since that
matches the expectations of bpf_helpers.h.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-07-15 23:13:17 +02:00
Stanislav Fomichev
395338843d samples/bpf: add sample program that periodically dumps TCP stats
Uses new RTT callback to dump stats every second.

$ mkdir -p /tmp/cgroupv2
$ mount -t cgroup2 none /tmp/cgroupv2
$ mkdir -p /tmp/cgroupv2/foo
$ echo $$ >> /tmp/cgroupv2/foo/cgroup.procs
$ bpftool prog load ./tcp_dumpstats_kern.o /sys/fs/bpf/tcp_prog
$ bpftool cgroup attach /tmp/cgroupv2/foo sock_ops pinned /sys/fs/bpf/tcp_prog
$ bpftool prog tracelog
$ # run neper/netperf/etc

Used neper to compare performance with and without this program attached
and didn't see any noticeable performance impact.

Sample output:
  <idle>-0     [015] ..s.  2074.128800: 0: dsack_dups=0 delivered=242526
  <idle>-0     [015] ..s.  2074.128808: 0: delivered_ce=0 icsk_retransmits=0
  <idle>-0     [015] ..s.  2075.130133: 0: dsack_dups=0 delivered=323599
  <idle>-0     [015] ..s.  2075.130138: 0: delivered_ce=0 icsk_retransmits=0
  <idle>-0     [005] .Ns.  2076.131440: 0: dsack_dups=0 delivered=404648
  <idle>-0     [005] .Ns.  2076.131447: 0: delivered_ce=0 icsk_retransmits=0

Cc: Eric Dumazet <edumazet@google.com>
Cc: Priyaranjan Jha <priyarjha@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-07-03 16:52:02 +02:00
brakmo
71634d7f92 bpf: Add support for fq's EDT to HBM
Adds support for fq's Earliest Departure Time to HBM (Host Bandwidth
Manager). Includes a new BPF program supporting EDT, and also updates
corresponding programs.

It will drop packets with an EDT of more than 500us in the future
unless the packet belongs to a flow with less than 2 packets in flight.
This is done so each flow has at least 2 packets in flight, so they
will not starve, and also to help prevent delayed ACK timeouts.

It will also work with ECN enabled traffic, where the packets will be
CE marked if their EDT is more than 50us in the future.

The table below shows some performance numbers. The flows are back to
back RPCS. One server sending to another, either 2 or 4 flows.
One flow is a 10KB RPC, the rest are 1MB RPCs. When there are more
than one flow of a given RPC size, the numbers represent averages.

The rate limit applies to all flows (they are in the same cgroup).
Tests ending with "-edt" ran with the new BPF program supporting EDT.
Tests ending with "-hbt" ran on top HBT qdisc with the specified rate
(i.e. no HBM). The other tests ran with the HBM BPF program included
in the HBM patch-set.

EDT has limited value when using DCTCP, but it helps in many cases when
using Cubic. It usually achieves larger link utilization and lower
99% latencies for the 1MB RPCs.
HBM ends up queueing a lot of packets with its default parameter values,
reducing the goodput of the 10KB RPCs and increasing their latency. Also,
the RTTs seen by the flows are quite large.

                         Aggr              10K  10K  10K   1MB  1MB  1MB
         Limit           rate drops  RTT  rate  P90  P99  rate  P90  P99
Test      rate  Flows    Mbps   %     us  Mbps   us   us  Mbps   ms   ms
--------  ----  -----    ---- -----  ---  ---- ---- ----  ---- ---- ----
cubic       1G    2       904  0.02  108   257  511  539   647 13.4 24.5
cubic-edt   1G    2       982  0.01  156   239  656  967   743 14.0 17.2
dctcp       1G    2       977  0.00  105   324  408  744   653 14.5 15.9
dctcp-edt   1G    2       981  0.01  142   321  417  811   660 15.7 17.0
cubic-htb   1G    2       919  0.00 1825    40 2822 4140   879  9.7  9.9

cubic     200M    2       155  0.30  220    81  532  655    74  283  450
cubic-edt 200M    2       188  0.02  222    87 1035 1095   101   84   85
dctcp     200M    2       188  0.03  111    77  912  939   111   76  325
dctcp-edt 200M    2       188  0.03  217    74 1416 1738   114   76   79
cubic-htb 200M    2       188  0.00 5015     8 14ms 15ms   180   48   50

cubic       1G    4       952  0.03  110   165  516  546   262   38  154
cubic-edt   1G    4       973  0.01  190   111 1034 1314   287   65   79
dctcp       1G    4       951  0.00  103   180  617  905   257   37   38
dctcp-edt   1G    4       967  0.00  163   151  732 1126   272   43   55
cubic-htb   1G    4       914  0.00 3249    13  7ms  8ms   300   29   34

cubic       5G    4      4236  0.00  134   305  490  624  1310   10   17
cubic-edt   5G    4      4865  0.00  156   306  425  759  1520   10   16
dctcp       5G    4      4936  0.00  128   485  221  409  1484    7    9
dctcp-edt   5G    4      4924  0.00  148   390  392  623  1508   11   26

v1 -> v2: Incorporated Andrii's suggestions
v2 -> v3: Incorporated Yonghong's suggestions
v3 -> v4: Removed credit update that is not needed

Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-07-03 15:03:00 +02:00
Daniel T. Lee
fa206dccd8 samples: bpf: remove unnecessary include options in Makefile
Due to recent change of include path at commit b552d33c80
("samples/bpf: fix include path in Makefile"), some of the
previous include options became unnecessary.

This commit removes duplicated include options in Makefile.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-18 00:28:36 +02:00
Prashant Bhole
b552d33c80 samples/bpf: fix include path in Makefile
Recent commit included libbpf.h in selftests/bpf/bpf_util.h.
Since some samples use bpf_util.h and samples/bpf/Makefile doesn't
have libbpf.h path included, build was failing. Let's add the path
in samples/bpf/Makefile.

Signed-off-by: Prashant Bhole <prashantbhole.linux@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-15 01:14:06 +02:00
Jakub Kicinski
0ed3cc4abc samples: bpf: don't run probes at the local make stage
Quentin reports that commit 07c3bbdb1a ("samples: bpf: print
a warning about headers_install") is producing the false
positive when make is invoked locally, from the samples/bpf/
directory.

When make is run locally it hits the "all" target, which
will recursively invoke make through the full build system.

Speed up the "local" run which doesn't actually build anything,
and avoid false positives by skipping all the probes if not in
kbuild environment (cover both the new warning and the BTF
probes).

Reported-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-06-10 23:37:20 -07:00
Jakub Kicinski
07c3bbdb1a samples: bpf: print a warning about headers_install
It seems like periodically someone posts patches to "fix"
header includes.  The issue is that samples expect the
include path to have the uAPI headers (from usr/) first,
and then tools/ headers, so that locally installed uAPI
headers take precedence.  This means that if users didn't
run headers_install they will see all sort of strange
compilation errors, e.g.:

  HOSTCC  samples/bpf/test_lru_dist
  samples/bpf/test_lru_dist.c:39:8: error: redefinition of ‘struct list_head’
   struct list_head {
          ^~~~~~~~~
   In file included from samples/bpf/test_lru_dist.c:9:0:
   ../tools/include/linux/types.h:69:8: note: originally defined here
    struct list_head {
           ^~~~~~~~~

Try to detect this situation, and print a helpful warning.

v2: just use HOSTCC (Jiong).

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-06 02:15:14 +02:00
Roman Gushchin
ba0c0cc05d selftests/bpf: convert test_cgrp2_attach2 example into kselftest
Convert test_cgrp2_attach2 example into a proper test_cgroup_attach
kselftest. It's better because we do run kselftest on a constant
basis, so there are better chances to spot a potential regression.

Also make it slightly less verbose to conform kselftests output style.

Output example:
  $ ./test_cgroup_attach
  #override:PASS
  #multi:PASS
  test_cgroup_attach:PASS

Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-05-28 09:30:02 -07:00
Ira Weiny
0ac01febd4 BPF: Add sample code for new ib_umad tracepoint
Provide a count of class types for a summary of MAD packets.  The example
shows one way to filter the trace data based on management class.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-03-27 15:53:26 -03:00
brakmo
a1270fe95b bpf: User program for testing HBM
The program nrm creates a cgroup and attaches a BPF program to the
cgroup for testing HBM (Host Bandwidth Manager) for egress traffic.
One still needs to create network traffic. This can be done through
netesto, netperf or iperf3.
A follow-up patch contains a script to create traffic.

USAGE: hbm [-d] [-l] [-n <id>] [-r <rate>] [-s] [-t <secs>]
           [-w] [-h] [prog]
  Where:
   -d        Print BPF trace debug buffer
   -l        Also limit flows doing loopback
   -n <#>    To create cgroup "/hbm#" and attach prog. Default is /nrm1
             This is convenient when testing HBM in more than 1 cgroup
   -r <rate> Rate limit in Mbps
   -s        Get HBM stats (marked, dropped, etc.)
   -t <time> Exit after specified seconds (deault is 0)
   -w        Work conserving flag. cgroup can increase its bandwidth
             beyond the rate limit specified while there is available
             bandwidth. Current implementation assumes there is only
             NIC (eth0), but can be extended to support multiple NICs.
             Currrently only supported for egress. Note, this is just
	     a proof of concept.
   -h        Print this info
   prog      BPF program file name. Name defaults to hbm_out_kern.o

More information about HBM can be found in the paper "BPF Host Resource
Management" presented at the 2018 Linux Plumbers Conference, Networking Track
(http://vger.kernel.org/lpc_net2018_talks/LPC%20BPF%20Network%20Resource%20Paper.pdf)

Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-03-02 10:48:27 -08:00
brakmo
187d0738ff bpf: Sample HBM BPF program to limit egress bw
A cgroup skb BPF program to limit cgroup output bandwidth.
It uses a modified virtual token bucket queue to limit average
egress bandwidth. The implementation uses credits instead of tokens.
Negative credits imply that queueing would have happened (this is
a virtual queue, so no queueing is done by it. However, queueing may
occur at the actual qdisc (which is not used for rate limiting).

This implementation uses 3 thresholds, one to start marking packets and
the other two to drop packets:
                                 CREDIT
       - <--------------------------|------------------------> +
             |    |          |      0
             |  Large pkt    |
             |  drop thresh  |
  Small pkt drop             Mark threshold
      thresh

The effect of marking depends on the type of packet:
a) If the packet is ECN enabled, then the packet is ECN ce marked.
   The current mark threshold is tuned for DCTCP.
c) Else, it is dropped if it is a large packet.

If the credit is below the drop threshold, the packet is dropped.
Note that dropping a packet through the BPF program does not trigger CWR
(Congestion Window Reduction) in TCP packets. A future patch will add
support for triggering CWR.

This BPF program actually uses 2 drop thresholds, one threshold
for larger packets (>= 120 bytes) and another for smaller packets. This
protects smaller packets such as SYNs, ACKs, etc.

The default bandwidth limit is set at 1Gbps but this can be changed by
a user program through a shared BPF map. In addition, by default this BPF
program does not limit connections using loopback. This behavior can be
overwritten by the user program. There is also an option to calculate
some statistics, such as percent of packets marked or dropped, which
the user program can access.

A latter patch provides such a program (hbm.c)

Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-03-02 10:48:27 -08:00
Jakub Kicinski
1a9b268c90 samples: bpf: use libbpf where easy
Some samples don't really need the magic of bpf_load,
switch them to libbpf.

v2: - specify program types.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-03-01 00:53:45 +01:00
Jakub Kicinski
ea9b636201 samples: bpf: remove load_sock_ops in favour of bpftool
bpftool can do all the things load_sock_ops used to do, and more.
Point users to bpftool instead of maintaining this sample utility.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-03-01 00:53:45 +01:00
Magnus Karlsson
248c7f9c0e samples/bpf: convert xdpsock to use libbpf for AF_XDP access
This commit converts the xdpsock sample application to use the AF_XDP
functions present in libbpf. This cuts down the size of it by nearly
300 lines of code.

The default ring sizes plus the batch size has been increased and the
size of the umem area has decreased. This so that the sample application
will provide higher throughput. Note also that the shared umem code
has been removed from the sample as this is not supported by libbpf
at this point in time.

Tested-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-02-25 23:21:42 +01:00
Maciej Fijalkowski
bbaf6029c4 samples/bpf: Convert XDP samples to libbpf usage
Some of XDP samples that are attaching the bpf program to the interface
via libbpf's bpf_set_link_xdp_fd are still using the bpf_load.c for
loading and manipulating the ebpf program and maps. Convert them to do
this through libbpf usage and remove bpf_load from the picture.

While at it remove what looks like debug leftover in
xdp_redirect_map_user.c

In xdp_redirect_cpu, change the way that the program to be loaded onto
interface is chosen - user now needs to pass the program's section name
instead of the relative number. In case of typo print out the section
names to choose from.

Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-02-01 23:37:51 +01:00