Currently if we hit an MP_JOIN failure on the third ack, the child socket is closed with reset, but the request socket is not deleted, causing weird behaviors.
The main problem is that MPTCP's MP_JOIN code needs to plug it's own 'valid 3rd ack' checks and the current TCP callbacks do not allow that. This series tries to address the above shortcoming introducing a new MPTCP specific bit in a 'struct sock' hole, and leveraging that to allow tcp_check_req releasing the request socket when needed. The above allows cleaning-up a bit current MPTCP hooking in tcp_check_req(). An alternative solution, possibly cleaner but more invasive, would be changing the 'bool *own_req' syn_recv_sock() argument into 'int *req_status' and let MPTCP set it to 'REQ_DROP'. Paolo Abeni (3): mptcp: add new sock flag to deal with join subflows inet_connection_sock: factor out destroy helper. mptcp: cope better with MP_JOIN failure include/linux/tcp.h | 1 + include/net/inet_connection_sock.h | 8 ++++++++ include/net/mptcp.h | 17 ++++++++++------- net/ipv4/inet_connection_sock.c | 6 +----- net/ipv4/tcp_minisocks.c | 2 +- net/mptcp/protocol.c | 7 ------- net/mptcp/subflow.c | 17 +++++++++++------ 7 files changed, 32 insertions(+), 26 deletions(-) -- 2.21.3
