[PATCH 0/2] bpf-next: Add socket destroy capability

[Aditi Ghag <aditi.ghag@isovalent.com>]

This patch adds the capability to destroy sockets in BPF.
We plan to use the capability in Cilium to force
client sockets to reconnect when their remote
load-balancing backends are deleted. The other use case
is on-the-fly policy enforcement where existing socket
connections prevented by policies need to
be terminated.
The use cases, and more details around the selected
approach was presented at LPC 2022 -
https://lpc.events/event/16/contributions/1358/.
RFC discussion -
https://lore.kernel.org/netdev/CABG=zsBEh-P4NXk23eBJw7eajB5YJeRS7oPXnTAzs=yob4EMoQ@mail.gmail.com/T/#u.

Notes to the reviewers:
- We evaluated different approaches to allow the
  `diag_destroy` handlers to acquire/skip locks from
  the BPF iterator programs. The commit description
  has all the details. The selected work queue approach
  was discussed with Daniel Borkmann. 
- We previously discussed the possibility of using
  sockmap to store sockets to be destroyed as an
  optimization, so that users may not need to iterate
  over all the host-wide sockets. This approach needs
  more discussion on the TCP side, as we may need to
  extend the logic that checks for certain TCP states
  while inserting sockets in a sockmap. So I've skipped
  those self test cases involving sockmap from the patch.

Aditi Ghag (2):
  bpf: Add socket destroy capability
  selftests/bpf: Add tests for bpf_sock_destroy

 include/linux/bpf.h                           |   1 +
 include/uapi/linux/bpf.h                      |  17 +++
 kernel/bpf/core.c                             |   1 +
 kernel/trace/bpf_trace.c                      |   2 +
 net/core/filter.c                             |  70 ++++++++++
 tools/include/uapi/linux/bpf.h                |  17 +++
 .../selftests/bpf/prog_tests/sock_destroy.c   | 131 ++++++++++++++++++
 .../selftests/bpf/progs/sock_destroy_prog.c   |  96 +++++++++++++
 8 files changed, 335 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/sock_destroy.c
 create mode 100644 tools/testing/selftests/bpf/progs/sock_destroy_prog.c


base-commit: 0e43662e61f2569500ab83b8188c065603530785
-- 
2.34.1