Commit 6477dd39 authored by Mat Martineau's avatar Mat Martineau Committed by David S. Miller
Browse files

mptcp: Retransmit DATA_FIN 

With this change, the MPTCP-level retransmission timer is used to resend
DATA_FIN. The retranmit timer is not stopped while waiting for a
MPTCP-level ACK of DATA_FIN, and retransmitted DATA_FINs are sent on all
subflows. The retry interval starts at TCP_RTO_MIN and then doubles on
each attempt, up to TCP_RTO_MAX.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/146


Fixes: 43b54c6e ("mptcp: Use full MPTCP-level disconnect state machine")
Acked-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d13f048d

net/mptcp/protocol.c

+23 −2
Original line number Diff line number Diff line
@@ -399,6 +399,14 @@ static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq) 
	return false;

}



static void mptcp_set_datafin_timeout(const struct sock *sk)

{

	struct inet_connection_sock *icsk = inet_csk(sk);



	mptcp_sk(sk)->timer_ival = min(TCP_RTO_MAX,

				       TCP_RTO_MIN << icsk->icsk_retransmits);

}



static void mptcp_set_timeout(const struct sock *sk, const struct sock *ssk)

{

	long tout = ssk && inet_csk(ssk)->icsk_pending ?
@@ -1052,7 +1060,7 @@ static void __mptcp_clean_una(struct sock *sk) 
	}



	if (snd_una == READ_ONCE(msk->snd_nxt)) {

		if (msk->timer_ival)

		if (msk->timer_ival && !mptcp_data_fin_enabled(msk))

			mptcp_stop_timer(sk);

	} else {

		mptcp_reset_timer(sk);
@@ -2276,8 +2284,19 @@ static void __mptcp_retrans(struct sock *sk) 


	__mptcp_clean_una_wakeup(sk);

	dfrag = mptcp_rtx_head(sk);

	if (!dfrag)

	if (!dfrag) {

		if (mptcp_data_fin_enabled(msk)) {

			struct inet_connection_sock *icsk = inet_csk(sk);



			icsk->icsk_retransmits++;

			mptcp_set_datafin_timeout(sk);

			mptcp_send_ack(msk);



			goto reset_timer;

		}



		return;

	}



	ssk = mptcp_subflow_get_retrans(msk);

	if (!ssk)
@@ -2460,6 +2479,8 @@ void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how) 
			pr_debug("Sending DATA_FIN on subflow %p", ssk);

			mptcp_set_timeout(sk, ssk);

			tcp_send_ack(ssk);

			if (!mptcp_timer_pending(sk))

				mptcp_reset_timer(sk);

		}

		break;

	}