Currently 5-tuple(sip+dip+sport+dport+proto) can't identify a
uniq connection because there may be multi net namespace.
For example, there may be a chance that netns a and netns b all
listen on 127.0.0.1:8080 and the client with same port 40782
connect to them. Without netns number, sock ops program
can't distinguish them.
Using bpf_get_netns_id helpers to get current connection
netns number to distinguish connections.

Changes in v4:
- rename get_netns_id_sock_ops to get_getns_id
- rebase from bpf-next

Changes in v3:
- rename sock_ops_get_netns to get_netns_id

Changes in v2:
- Return u64 instead of u32 for sock_ops_get_netns
- Fix build bug when CONFIG_NET_NS not set
- Add selftest for sock_ops_get_netns

Lingpeng Chen (3):
  bpf: Add get_netns_id helper function for sock_ops
  bpf: Sync uapi bpf.h to tools/
  selftests/bpf: add selftest for get_netns_id helper

 include/uapi/linux/bpf.h                      |  9 +++-
 net/core/filter.c                             | 20 ++++++++
 tools/include/uapi/linux/bpf.h                |  9 +++-
 .../selftests/bpf/progs/test_tcpbpf_kern.c    | 11 +++++
 .../testing/selftests/bpf/test_tcpbpf_user.c  | 46 ++++++++++++++++++-
 5 files changed, 92 insertions(+), 3 deletions(-)


base-commit e0360423d020
("selftests/bpf: Run SYN cookies with reuseport BPF test only for TCP")
-- 
2.20.1