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-rw-r--r--net/mptcp/protocol.c51
1 files changed, 42 insertions, 9 deletions
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 6db93da59843..b100048e43fe 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1596,7 +1596,8 @@ static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk)
if (!xmit_ssk)
goto out;
if (xmit_ssk != ssk) {
- mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk));
+ mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk),
+ MPTCP_DELEGATE_SEND);
goto out;
}
@@ -2943,7 +2944,7 @@ void __mptcp_check_push(struct sock *sk, struct sock *ssk)
if (xmit_ssk == ssk)
__mptcp_subflow_push_pending(sk, ssk);
else if (xmit_ssk)
- mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk));
+ mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk), MPTCP_DELEGATE_SEND);
} else {
set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags);
}
@@ -2993,18 +2994,50 @@ static void mptcp_release_cb(struct sock *sk)
__mptcp_update_rmem(sk);
}
+/* MP_JOIN client subflow must wait for 4th ack before sending any data:
+ * TCP can't schedule delack timer before the subflow is fully established.
+ * MPTCP uses the delack timer to do 3rd ack retransmissions
+ */
+static void schedule_3rdack_retransmission(struct sock *ssk)
+{
+ struct inet_connection_sock *icsk = inet_csk(ssk);
+ struct tcp_sock *tp = tcp_sk(ssk);
+ unsigned long timeout;
+
+ if (mptcp_subflow_ctx(ssk)->fully_established)
+ return;
+
+ /* reschedule with a timeout above RTT, as we must look only for drop */
+ if (tp->srtt_us)
+ timeout = usecs_to_jiffies(tp->srtt_us >> (3 - 1));
+ else
+ timeout = TCP_TIMEOUT_INIT;
+ timeout += jiffies;
+
+ WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER);
+ icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
+ icsk->icsk_ack.timeout = timeout;
+ sk_reset_timer(ssk, &icsk->icsk_delack_timer, timeout);
+}
+
void mptcp_subflow_process_delegated(struct sock *ssk)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
struct sock *sk = subflow->conn;
- mptcp_data_lock(sk);
- if (!sock_owned_by_user(sk))
- __mptcp_subflow_push_pending(sk, ssk);
- else
- set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags);
- mptcp_data_unlock(sk);
- mptcp_subflow_delegated_done(subflow);
+ if (test_bit(MPTCP_DELEGATE_SEND, &subflow->delegated_status)) {
+ mptcp_data_lock(sk);
+ if (!sock_owned_by_user(sk))
+ __mptcp_subflow_push_pending(sk, ssk);
+ else
+ set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags);
+ mptcp_data_unlock(sk);
+ mptcp_subflow_delegated_done(subflow, MPTCP_DELEGATE_SEND);
+ }
+ if (test_bit(MPTCP_DELEGATE_ACK, &subflow->delegated_status)) {
+ schedule_3rdack_retransmission(ssk);
+ mptcp_subflow_delegated_done(subflow, MPTCP_DELEGATE_ACK);
+ }
}
static int mptcp_hash(struct sock *sk)