Commit 7769f406 authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by David S. Miller
Browse files

[TCP]: Fix logic breakage due to DSACK separation 



Commit 6f74651a is found guilty
of breaking DSACK counting, which should be done only for the
SACK block reported by the DSACK instead of every SACK block
that is received along with DSACK information.

Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b9ce204f

net/ipv4/tcp_input.c

+5 −4
Original line number Diff line number Diff line
@@ -953,7 +953,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_ 
	int prior_fackets;

	u32 lost_retrans = 0;

	int flag = 0;

	int dup_sack = 0;

	int found_dup_sack = 0;

	int cached_fack_count;

	int i;

	int first_sack_index;
@@ -964,20 +964,20 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_ 


	/* Check for D-SACK. */

	if (before(ntohl(sp[0].start_seq), TCP_SKB_CB(ack_skb)->ack_seq)) {

		dup_sack = 1;

		found_dup_sack = 1;

		tp->rx_opt.sack_ok |= 4;

		NET_INC_STATS_BH(LINUX_MIB_TCPDSACKRECV);

	} else if (num_sacks > 1 &&

			!after(ntohl(sp[0].end_seq), ntohl(sp[1].end_seq)) &&

			!before(ntohl(sp[0].start_seq), ntohl(sp[1].start_seq))) {

		dup_sack = 1;

		found_dup_sack = 1;

		tp->rx_opt.sack_ok |= 4;

		NET_INC_STATS_BH(LINUX_MIB_TCPDSACKOFORECV);

	}



	/* D-SACK for already forgotten data...

	 * Do dumb counting. */

	if (dup_sack &&

	if (found_dup_sack &&

			!after(ntohl(sp[0].end_seq), prior_snd_una) &&

			after(ntohl(sp[0].end_seq), tp->undo_marker))

		tp->undo_retrans--;
@@ -1058,6 +1058,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_ 
		__u32 start_seq = ntohl(sp->start_seq);

		__u32 end_seq = ntohl(sp->end_seq);

		int fack_count;

		int dup_sack = (found_dup_sack && (i == first_sack_index));



		skb = cached_skb;

		fack_count = cached_fack_count;

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