30 Oct, 2016

1 commit

• 96a8eb1ee   bpf: fix samples to add fake KBUILD_MODNAME ... Browse Code »

  Some of the sample files are causing issues when they are loaded with tc
  and cls_bpf, meaning tc bails out while trying to parse the resulting ELF
  file as program/map/etc sections are not present, which can be easily
  spotted with readelf(1).

  Currently, BPF samples are including some of the kernel headers and mid
  term we should change them to refrain from this, really. When dynamic
  debugging is enabled, we bail out due to undeclared KBUILD_MODNAME, which
  is easily overlooked in the build as clang spills this along with other
  noisy warnings from various header includes, and llc still generates an
  ELF file with mentioned characteristics. For just playing around with BPF
  examples, this can be a bit of a hurdle to take.

  Just add a fake KBUILD_MODNAME as a band-aid to fix the issue, same is
  done in xdp*_kern samples already.

  Fixes: 65d472fb007d ("samples/bpf: add 'pointer to packet' tests")
  Fixes: 6afb1e28b859 ("samples/bpf: Add tunnel set/get tests.")
  Fixes: a3f74617340b ("cgroup: bpf: Add an example to do cgroup checking in BPF")
  Reported-by: Chandrasekar Kannan
  Signed-off-by: Daniel Borkmann
  Acked-by: Alexei Starovoitov
  Signed-off-by: David S. Miller

  Daniel Borkmann

  2016-10-30 02:46:12 +0800  

13 Aug, 2016

1 commit

• 747ea55e4   bpf: fix bpf_skb_in_cgroup helper naming ... Browse Code »

  While hashing out BPF's current_task_under_cgroup helper bits, it came
  to discussion that the skb_in_cgroup helper name was suboptimally chosen.

  Tejun says:

  So, I think in_cgroup should mean that the object is in that
  particular cgroup while under_cgroup in the subhierarchy of that
  cgroup. Let's rename the other subhierarchy test to under too. I
  think that'd be a lot less confusing going forward.

  [...]

  It's more intuitive and gives us the room to implement the real
  "in" test if ever necessary in the future.

  Since this touches uapi bits, we need to change this as long as v4.8
  is not yet officially released. Thus, change the helper enum and rename
  related bits.

  Fixes: 4a482f34afcc ("cgroup: bpf: Add bpf_skb_in_cgroup_proto")
  Reference: http://patchwork.ozlabs.org/patch/658500/
  Suggested-by: Sargun Dhillon
  Suggested-by: Tejun Heo
  Signed-off-by: Daniel Borkmann
  Acked-by: Alexei Starovoitov

  Daniel Borkmann

  2016-08-13 12:53:33 +0800  

02 Jul, 2016

1 commit

• a3f746173   cgroup: bpf: Add an example to do cgroup checking in BPF ... Browse Code »

  test_cgrp2_array_pin.c:
  A userland program that creates a bpf_map (BPF_MAP_TYPE_GROUP_ARRAY),
  pouplates/updates it with a cgroup2's backed fd and pins it to a
  bpf-fs's file. The pinned file can be loaded by tc and then used
  by the bpf prog later. This program can also update an existing pinned
  array and it could be useful for debugging/testing purpose.

  test_cgrp2_tc_kern.c:
  A bpf prog which should be loaded by tc. It is to demonstrate
  the usage of bpf_skb_in_cgroup.

  test_cgrp2_tc.sh:
  A script that glues the test_cgrp2_array_pin.c and
  test_cgrp2_tc_kern.c together. The idea is like:
  1. Load the test_cgrp2_tc_kern.o by tc
  2. Use test_cgrp2_array_pin.c to populate a BPF_MAP_TYPE_CGROUP_ARRAY
  with a cgroup fd
  3. Do a 'ping -6 ff02::1%ve' to ensure the packet has been
  dropped because of a match on the cgroup

  Most of the lines in test_cgrp2_tc.sh is the boilerplate
  to setup the cgroup/bpf-fs/net-devices/netns...etc. It is
  not bulletproof on errors but should work well enough and
  give enough debug info if things did not go well.

  Signed-off-by: Martin KaFai Lau
  Cc: Alexei Starovoitov
  Cc: Daniel Borkmann
  Cc: Tejun Heo
  Acked-by: Alexei Starovoitov
  Signed-off-by: David S. Miller

  Martin KaFai Lau

  2016-07-02 04:32:13 +0800