From 7ed90803a213736290bdcf971764ddb8ff3fa44f Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Mon, 16 Nov 2020 10:48:14 +0100 Subject: [PATCH] mptcp: send explicit ack on delayed ack_seq incr When the worker moves some bytes from the OoO queue into the receive queue, the msk->ask_seq is updated, the MPTCP-level ack carrying that value needs to wait the next ingress packet, possibly slowing down or hanging the peer Signed-off-by: Paolo Abeni Signed-off-by: Jakub Kicinski --- net/mptcp/protocol.c | 34 +++++++++++++++++++++------------- 1 file changed, 21 insertions(+), 13 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 5a92b9239909..8df013daea88 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -407,13 +407,27 @@ static void mptcp_set_timeout(const struct sock *sk, const struct sock *ssk) mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN; } -static void mptcp_check_data_fin(struct sock *sk) +static void mptcp_send_ack(struct mptcp_sock *msk) +{ + struct mptcp_subflow_context *subflow; + + mptcp_for_each_subflow(msk, subflow) { + struct sock *ssk = mptcp_subflow_tcp_sock(subflow); + + lock_sock(ssk); + tcp_send_ack(ssk); + release_sock(ssk); + } +} + +static bool mptcp_check_data_fin(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); u64 rcv_data_fin_seq; + bool ret = false; if (__mptcp_check_fallback(msk) || !msk->first) - return; + return ret; /* Need to ack a DATA_FIN received from a peer while this side * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2. @@ -429,8 +443,6 @@ static void mptcp_check_data_fin(struct sock *sk) */ if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) { - struct mptcp_subflow_context *subflow; - WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1); WRITE_ONCE(msk->rcv_data_fin, 0); @@ -454,17 +466,12 @@ static void mptcp_check_data_fin(struct sock *sk) break; } + ret = true; mptcp_set_timeout(sk, NULL); - mptcp_for_each_subflow(msk, subflow) { - struct sock *ssk = mptcp_subflow_tcp_sock(subflow); - - lock_sock(ssk); - tcp_send_ack(ssk); - release_sock(ssk); - } - + mptcp_send_ack(msk); mptcp_close_wake_up(sk); } + return ret; } static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk, @@ -1547,7 +1554,8 @@ static bool __mptcp_move_skbs(struct mptcp_sock *msk) } while (!done); if (mptcp_ofo_queue(msk) || moved > 0) { - mptcp_check_data_fin((struct sock *)msk); + if (!mptcp_check_data_fin((struct sock *)msk)) + mptcp_send_ack(msk); return true; } return false; -- 2.20.1