[PATCH mptcp-next v3 0/7] mptcp: add bpf_setsockopt support

[Gang Yan <gang.yan@linux.dev>]

From: Gang Yan <yangang@kylinos.cn>

Hi, Matt, Geliang, Paolo

Patch 3-4 have been reviewed by Paolo before, and ready for merge
[1][2].

Changelog:
v3:
  - Patch 2 keeps the mptcp_setsockopt_all_sf as Geliang suggested.
v2:
  - Patches 1 and 2 are new in this series; they address TCP_MAXSEG
    handling in the bpf_setsockopt() path.
  - Patch 4 adds an early return to fix msk->sk_rcvlowat being
    unexpectedly modified, an issue seen in v1.
  - Patch 5 makes the hook safe for the non-tcp master socket: it guards
    bpf_sock_ops_cb_flags_set() with sk_is_tcp() to prevent out-of-bounds
    heap reads/writes through tcp_sk(sk)->bpf_sock_ops_cb_flags, and does
    not set is_locked_tcp_sock for the msk (unlike tcp_call_bpf()). That
    flag authorizes the verifier's direct tcp_sock-offset field accesses;
    since the msk is not a tcp_sock, leaving it at the default 0 is safe.

v1:
  Link: https://patchwork.kernel.org/project/mptcp/cover/20260713095735.1222033-1-gang.yan@linux.dev/

[1] https://patchwork.kernel.org/project/mptcp/patch/20260522-sockopt_lock-v5-2-108629a46e98@kylinos.cn/
[2] https://patchwork.kernel.org/project/mptcp/patch/20260522-sockopt_lock-v5-4-108629a46e98@kylinos.cn/

Gang Yan (7):
  mptcp: drop unused @max arg of __mptcp_setsockopt_set_val
  mptcp: take TCP_MAXSEG handling into __mptcp_setsockopt_set_val
  mptcp: use sockopt_lock/release_sock in sockopt
  mptcp: reject sockopt requiring ssks' lock in BPF context
  mptcp: enable bpf_setsockopt on the master socket
  mptcp: add TCP_CONNECT_CB sock_ops hook
  selftests: bpf: verify mptcp bpf_setsockopt from TCP_CONNECT_CB

 include/net/mptcp.h                           |   9 ++
 net/core/filter.c                             |  10 ++
 net/ipv4/tcp.c                                |   1 +
 net/mptcp/protocol.c                          |   6 +
 net/mptcp/protocol.h                          |  29 ++++
 net/mptcp/sockopt.c                           | 127 +++++++++++-------
 .../testing/selftests/bpf/prog_tests/mptcp.c  |  61 +++++++++
 .../selftests/bpf/progs/mptcp_setsockopt.c    |  32 +++++
 8 files changed, 223 insertions(+), 52 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/progs/mptcp_setsockopt.c

-- 
2.43.0