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Commit 1fdb9361 authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by David S. Miller
Browse files

tcp: sack lost marking fixes 



When only fast rexmit should be done, tcp_mark_head_lost marks
L too far. Also, sacked_upto below 1 is perfectly valid number,
the packets == 0 then needs to be trapped elsewhere.

Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f3e85df8

net/ipv4/tcp_input.c

+14 −10
Original line number Diff line number Diff line
@@ -2495,7 +2495,7 @@ static void tcp_timeout_skbs(struct sock *sk) 
/* Mark head of queue up as lost. With RFC3517 SACK, the packets is

 * is against sacked "cnt", otherwise it's against facked "cnt"

 */

static void tcp_mark_head_lost(struct sock *sk, int packets)

static void tcp_mark_head_lost(struct sock *sk, int packets, int mark_head)

{

	struct tcp_sock *tp = tcp_sk(sk);

	struct sk_buff *skb;
@@ -2503,13 +2503,13 @@ static void tcp_mark_head_lost(struct sock *sk, int packets) 
	int err;

	unsigned int mss;



	if (packets == 0)

		return;



	WARN_ON(packets > tp->packets_out);

	if (tp->lost_skb_hint) {

		skb = tp->lost_skb_hint;

		cnt = tp->lost_cnt_hint;

		/* Head already handled? */

		if (mark_head && skb != tcp_write_queue_head(sk))

			return;

	} else {

		skb = tcp_write_queue_head(sk);

		cnt = 0;
@@ -2544,6 +2544,9 @@ static void tcp_mark_head_lost(struct sock *sk, int packets) 
		}



		tcp_skb_mark_lost(tp, skb);



		if (mark_head)

			break;

	}

	tcp_verify_left_out(tp);

}
@@ -2555,17 +2558,18 @@ static void tcp_update_scoreboard(struct sock *sk, int fast_rexmit) 
	struct tcp_sock *tp = tcp_sk(sk);



	if (tcp_is_reno(tp)) {

		tcp_mark_head_lost(sk, 1);

		tcp_mark_head_lost(sk, 1, 1);

	} else if (tcp_is_fack(tp)) {

		int lost = tp->fackets_out - tp->reordering;

		if (lost <= 0)

			lost = 1;

		tcp_mark_head_lost(sk, lost);

		tcp_mark_head_lost(sk, lost, 0);

	} else {

		int sacked_upto = tp->sacked_out - tp->reordering;

		if (sacked_upto < fast_rexmit)

			sacked_upto = fast_rexmit;

		tcp_mark_head_lost(sk, sacked_upto);

		if (sacked_upto >= 0)

			tcp_mark_head_lost(sk, sacked_upto, 0);

		else if (fast_rexmit)

			tcp_mark_head_lost(sk, 1, 1);

	}



	tcp_timeout_skbs(sk);
@@ -2971,7 +2975,7 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, int flag) 
	    before(tp->snd_una, tp->high_seq) &&

	    icsk->icsk_ca_state != TCP_CA_Open &&

	    tp->fackets_out > tp->reordering) {

		tcp_mark_head_lost(sk, tp->fackets_out - tp->reordering);

		tcp_mark_head_lost(sk, tp->fackets_out - tp->reordering, 0);

		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPLOSS);

	}