diff mbox series

[v3,13/13] mptcp: send explicit ack on delayed ack_seq incr

Message ID 6b46da79c7efd8cd85b971f7d4b81ffa58d08f80.1601630384.git.pabeni@redhat.com
State Accepted, archived
Delegated to: Matthieu Baerts
Headers show
Series mptcp: support for queuing data at mptcp-level | expand

Commit Message

Paolo Abeni Oct. 2, 2020, 9:26 a.m. UTC 
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 <pabeni@redhat.com>
---
v2 -> v3:
 - add commit message ;)
---
 net/mptcp/protocol.c | 36 ++++++++++++++++++++++--------------
 1 file changed, 22 insertions(+), 14 deletions(-)
diff mbox series

Patch

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index ba1209c75994..6b5a8f8d2175 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -395,13 +395,27 @@  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.
@@ -417,8 +431,6 @@  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);
 
@@ -442,17 +454,11 @@  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);
 		if (sock_flag(sk, SOCK_DEAD))
-			return;
+			return ret;
 
 		sk->sk_state_change(sk);
 		if (sk->sk_shutdown == SHUTDOWN_MASK ||
@@ -461,6 +467,7 @@  static void mptcp_check_data_fin(struct sock *sk)
 		else
 			sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
 	}
+	return ret;
 }
 
 static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
@@ -1523,7 +1530,8 @@  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;