[PATCH v4 net-next 0/3] net: skb: introduce kfree_skb_with_reason()

[menglong8.dong@gmail.com]

From: Menglong Dong <imagedong@tencent.com>

In this series patch, the interface kfree_skb_with_reason() is
introduced(), which is used to collect skb drop reason, and pass
it to 'kfree_skb' tracepoint. Therefor, 'drop_monitor' or eBPF is
able to monitor abnormal skb with detail reason.

In fact, this series patches are out of the intelligence of David
and Steve, I'm just a truck man :/

Previous discussion is here:

https://lore.kernel.org/netdev/20211118105752.1d46e990@gandalf.local.home/
https://lore.kernel.org/netdev/67b36bd8-2477-88ac-83a0-35a1eeaf40c9@gmail.com/

In the first patch, kfree_skb_with_reason() is introduced and
the 'reason' field is added to 'kfree_skb' tracepoint. In the
second patch, 'kfree_skb()' in replaced with 'kfree_skb_with_reason()'
in tcp_v4_rcv(). In the third patch, 'kfree_skb_with_reason()' is
used in __udp4_lib_rcv().

Changes since v3:
- fix some code style problems in skb.h

Changes since v2:
- rename kfree_skb_with_reason() to kfree_skb_reason()
- make kfree_skb() static inline, as Jakub suggested

Changes since v1:
- rename some drop reason, as David suggested
- add the third patch


Menglong Dong (3):
  net: bpf: handle return value of 
    BPF_CGROUP_RUN_PROG_INET{4,6}_POST_BIND()
  bpf: selftests: use C99 initializers in test_sock.c
  bpf: selftests: add bind retry for post_bind{4, 6}

 include/net/sock.h                      |   1 +
 net/ipv4/af_inet.c                      |   2 +
 net/ipv4/ping.c                         |   1 +
 net/ipv4/tcp_ipv4.c                     |   1 +
 net/ipv4/udp.c                          |   1 +
 net/ipv6/af_inet6.c                     |   2 +
 net/ipv6/ping.c                         |   1 +
 net/ipv6/tcp_ipv6.c                     |   1 +
 net/ipv6/udp.c                          |   1 +
 tools/testing/selftests/bpf/test_sock.c | 370 ++++++++++++++----------
 10 files changed, 233 insertions(+), 148 deletions(-)

-- 
2.27.0