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Commit 1fbc3405 authored by Yuchung Cheng's avatar Yuchung Cheng Committed by David S. Miller
Browse files

tcp: early retransmit: tcp_enter_recovery() 



This a prepartion patch that refactors the code to enter recovery
into a new function tcp_enter_recovery(). It's needed to implement
the delayed fast retransmit in ER.

Signed-off-by: default avatarYuchung Cheng <ycheng@google.com>
Acked-by: default avatarNeal Cardwell <ncardwell@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 5c6239c8

net/ipv4/tcp_input.c

+34 −27
Original line number Original line Diff line number Diff line
@@ -3022,6 +3022,38 @@ static void tcp_update_cwnd_in_recovery(struct sock *sk, int newly_acked_sacked, 
	tp->snd_cwnd = tcp_packets_in_flight(tp) + sndcnt;

	tp->snd_cwnd = tcp_packets_in_flight(tp) + sndcnt;

}

}





static void tcp_enter_recovery(struct sock *sk, bool ece_ack)

{

	struct tcp_sock *tp = tcp_sk(sk);

	int mib_idx;



	if (tcp_is_reno(tp))

		mib_idx = LINUX_MIB_TCPRENORECOVERY;

	else

		mib_idx = LINUX_MIB_TCPSACKRECOVERY;



	NET_INC_STATS_BH(sock_net(sk), mib_idx);



	tp->high_seq = tp->snd_nxt;

	tp->prior_ssthresh = 0;

	tp->undo_marker = tp->snd_una;

	tp->undo_retrans = tp->retrans_out;



	if (inet_csk(sk)->icsk_ca_state < TCP_CA_CWR) {

		if (!ece_ack)

			tp->prior_ssthresh = tcp_current_ssthresh(sk);

		tp->snd_ssthresh = inet_csk(sk)->icsk_ca_ops->ssthresh(sk);

		TCP_ECN_queue_cwr(tp);

	}



	tp->bytes_acked = 0;

	tp->snd_cwnd_cnt = 0;

	tp->prior_cwnd = tp->snd_cwnd;

	tp->prr_delivered = 0;

	tp->prr_out = 0;

	tcp_set_ca_state(sk, TCP_CA_Recovery);

}



/* Process an event, which can update packets-in-flight not trivially.

/* Process an event, which can update packets-in-flight not trivially.

 * Main goal of this function is to calculate new estimate for left_out,

 * Main goal of this function is to calculate new estimate for left_out,

 * taking into account both packets sitting in receiver's buffer and

 * taking into account both packets sitting in receiver's buffer and
@@ -3041,7 +3073,7 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, 
	struct tcp_sock *tp = tcp_sk(sk);

	struct tcp_sock *tp = tcp_sk(sk);

	int do_lost = is_dupack || ((flag & FLAG_DATA_SACKED) &&

	int do_lost = is_dupack || ((flag & FLAG_DATA_SACKED) &&

				    (tcp_fackets_out(tp) > tp->reordering));

				    (tcp_fackets_out(tp) > tp->reordering));

	int fast_rexmit = 0, mib_idx;

	int fast_rexmit = 0;





	if (WARN_ON(!tp->packets_out && tp->sacked_out))

	if (WARN_ON(!tp->packets_out && tp->sacked_out))

		tp->sacked_out = 0;

		tp->sacked_out = 0;
@@ -3142,32 +3174,7 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, 
		}

		}





		/* Otherwise enter Recovery state */

		/* Otherwise enter Recovery state */



		tcp_enter_recovery(sk, (flag & FLAG_ECE));

		if (tcp_is_reno(tp))

			mib_idx = LINUX_MIB_TCPRENORECOVERY;

		else

			mib_idx = LINUX_MIB_TCPSACKRECOVERY;



		NET_INC_STATS_BH(sock_net(sk), mib_idx);



		tp->high_seq = tp->snd_nxt;

		tp->prior_ssthresh = 0;

		tp->undo_marker = tp->snd_una;

		tp->undo_retrans = tp->retrans_out;



		if (icsk->icsk_ca_state < TCP_CA_CWR) {

			if (!(flag & FLAG_ECE))

				tp->prior_ssthresh = tcp_current_ssthresh(sk);

			tp->snd_ssthresh = icsk->icsk_ca_ops->ssthresh(sk);

			TCP_ECN_queue_cwr(tp);

		}



		tp->bytes_acked = 0;

		tp->snd_cwnd_cnt = 0;

		tp->prior_cwnd = tp->snd_cwnd;

		tp->prr_delivered = 0;

		tp->prr_out = 0;

		tcp_set_ca_state(sk, TCP_CA_Recovery);

		fast_rexmit = 1;

		fast_rexmit = 1;

	}

	}