Commit b51f9b80 authored by Paolo Abeni's avatar Paolo Abeni Committed by David S. Miller
Browse files

mptcp: introduce MPTCP retransmission timer 



The timer will be used to schedule retransmission. It's
frequency is based on the current subflow RTO estimation and
is reset on every una_seq update

The timer is clearer for good by __mptcp_clear_xmit()

Also clean MPTCP rtx queue before each transmission.

Signed-off-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 18b683bf

net/mptcp/options.c

+3 −1
Original line number Diff line number Diff line
@@ -779,10 +779,12 @@ static void update_una(struct mptcp_sock *msk, 
		snd_una = old_snd_una;

		old_snd_una = atomic64_cmpxchg(&msk->snd_una, snd_una,

					       new_snd_una);

		if (old_snd_una == snd_una)

		if (old_snd_una == snd_una) {

			mptcp_data_acked((struct sock *)msk);

			break;

		}

	}

}



static bool add_addr_hmac_valid(struct mptcp_sock *msk,

				struct mptcp_options_received *mp_opt)

net/mptcp/protocol.c

+88 −1
Original line number Diff line number Diff line
@@ -251,6 +251,46 @@ static void __mptcp_flush_join_list(struct mptcp_sock *msk) 
	spin_unlock_bh(&msk->join_list_lock);

}



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

{

	long tout = ssk && inet_csk(ssk)->icsk_pending ?

				      inet_csk(ssk)->icsk_timeout - jiffies : 0;



	if (tout <= 0)

		tout = mptcp_sk(sk)->timer_ival;

	mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN;

}



static bool mptcp_timer_pending(struct sock *sk)

{

	return timer_pending(&inet_csk(sk)->icsk_retransmit_timer);

}



static void mptcp_reset_timer(struct sock *sk)

{

	struct inet_connection_sock *icsk = inet_csk(sk);

	unsigned long tout;



	/* should never be called with mptcp level timer cleared */

	tout = READ_ONCE(mptcp_sk(sk)->timer_ival);

	if (WARN_ON_ONCE(!tout))

		tout = TCP_RTO_MIN;

	sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout);

}



void mptcp_data_acked(struct sock *sk)

{

	mptcp_reset_timer(sk);

}



static void mptcp_stop_timer(struct sock *sk)

{

	struct inet_connection_sock *icsk = inet_csk(sk);



	sk_stop_timer(sk, &icsk->icsk_retransmit_timer);

	mptcp_sk(sk)->timer_ival = 0;

}



static bool mptcp_ext_cache_refill(struct mptcp_sock *msk)

{

	if (!msk->cached_ext)
@@ -596,10 +636,15 @@ fallback: 
		copied += ret;

	}



	mptcp_set_timeout(sk, ssk);

	if (copied) {

		ret = copied;

		tcp_push(ssk, msg->msg_flags, mss_now, tcp_sk(ssk)->nonagle,

			 size_goal);



		/* start the timer, if it's not pending */

		if (!mptcp_timer_pending(sk))

			mptcp_reset_timer(sk);

	}



	ssk_check_wmem(msk, ssk);
@@ -787,6 +832,35 @@ out_err: 
	return copied;

}



static void mptcp_retransmit_handler(struct sock *sk)

{

	struct mptcp_sock *msk = mptcp_sk(sk);



	if (atomic64_read(&msk->snd_una) == msk->write_seq)

		mptcp_stop_timer(sk);

	else

		mptcp_reset_timer(sk);

}



static void mptcp_retransmit_timer(struct timer_list *t)

{

	struct inet_connection_sock *icsk = from_timer(icsk, t,

						       icsk_retransmit_timer);

	struct sock *sk = &icsk->icsk_inet.sk;



	bh_lock_sock(sk);

	if (!sock_owned_by_user(sk)) {

		mptcp_retransmit_handler(sk);

	} else {

		/* delegate our work to tcp_release_cb() */

		if (!test_and_set_bit(TCP_WRITE_TIMER_DEFERRED,

				      &sk->sk_tsq_flags))

			sock_hold(sk);

	}

	bh_unlock_sock(sk);

	sock_put(sk);

}



/* subflow sockets can be either outgoing (connect) or incoming

 * (accept).

 *
@@ -846,6 +920,9 @@ static int __mptcp_init_sock(struct sock *sk) 


	mptcp_pm_data_init(msk);



	/* re-use the csk retrans timer for MPTCP-level retrans */

	timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0);



	return 0;

}
@@ -867,6 +944,8 @@ static void __mptcp_clear_xmit(struct sock *sk) 
	struct mptcp_sock *msk = mptcp_sk(sk);

	struct mptcp_data_frag *dtmp, *dfrag;



	sk_stop_timer(sk, &msk->sk.icsk_retransmit_timer);



	list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list)

		dfrag_clear(dfrag);

}
@@ -1155,7 +1234,8 @@ static int mptcp_getsockopt(struct sock *sk, int level, int optname, 
	return -EOPNOTSUPP;

}



#define MPTCP_DEFERRED_ALL TCPF_DELACK_TIMER_DEFERRED

#define MPTCP_DEFERRED_ALL (TCPF_DELACK_TIMER_DEFERRED | \

			    TCPF_WRITE_TIMER_DEFERRED)



/* this is very alike tcp_release_cb() but we must handle differently a

 * different set of events
@@ -1171,6 +1251,8 @@ static void mptcp_release_cb(struct sock *sk) 
		nflags = flags & ~MPTCP_DEFERRED_ALL;

	} while (cmpxchg(&sk->sk_tsq_flags, flags, nflags) != flags);



	sock_release_ownership(sk);



	if (flags & TCPF_DELACK_TIMER_DEFERRED) {

		struct mptcp_sock *msk = mptcp_sk(sk);

		struct sock *ssk;
@@ -1179,6 +1261,11 @@ static void mptcp_release_cb(struct sock *sk) 
		if (!ssk || !schedule_work(&msk->work))

			__sock_put(sk);

	}



	if (flags & TCPF_WRITE_TIMER_DEFERRED) {

		mptcp_retransmit_handler(sk);

		__sock_put(sk);

	}

}



static int mptcp_get_port(struct sock *sk, unsigned short snum)

net/mptcp/protocol.h

+2 −0
Original line number Diff line number Diff line
@@ -157,6 +157,7 @@ struct mptcp_sock { 
	u64		write_seq;

	u64		ack_seq;

	atomic64_t	snd_una;

	unsigned long	timer_ival;

	u32		token;

	unsigned long	flags;

	bool		can_ack;
@@ -326,6 +327,7 @@ void mptcp_get_options(const struct sk_buff *skb, 
void mptcp_finish_connect(struct sock *sk);

void mptcp_data_ready(struct sock *sk, struct sock *ssk);

bool mptcp_finish_join(struct sock *sk);

void mptcp_data_acked(struct sock *sk);



int mptcp_token_new_request(struct request_sock *req);

void mptcp_token_destroy_request(u32 token);

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