1 files changed, 17 insertions, 9 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 38cb25b48bf..4e5884ac8f2 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -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;
@@ -1397,7 +1398,9 @@ static void tcp_enter_frto_loss(struct sock *sk, int allowed_segments, int flag)
 		 * waiting for the first ACK and did not get it)...
 		 */
 		if ((tp->frto_counter == 1) && !(flag&FLAG_DATA_ACKED)) {
-			tp->retrans_out += tcp_skb_pcount(skb);
+			/* For some reason this R-bit might get cleared? */
+			if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_RETRANS)
+				tp->retrans_out += tcp_skb_pcount(skb);
 			/* ...enter this if branch just for the first segment */
 			flag |= FLAG_DATA_ACKED;
 		} else {
@@ -2037,7 +2040,7 @@ static void tcp_try_to_open(struct sock *sk, int flag)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 
-	tp->left_out = tp->sacked_out;
+	tcp_sync_left_out(tp);
 
 	if (tp->retrans_out == 0)
 		tp->retrans_stamp = 0;
@@ -2407,9 +2410,9 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
 	struct sk_buff *skb;
 	__u32 now = tcp_time_stamp;
 	int acked = 0;
+	int prior_packets = tp->packets_out;
 	__s32 seq_rtt = -1;
-	u32 pkts_acked = 0;
-	ktime_t last_ackt = ktime_set(0,0);
+	ktime_t last_ackt = net_invalid_timestamp();
 
 	while ((skb = tcp_write_queue_head(sk)) &&
 	       skb != tcp_send_head(sk)) {
@@ -2437,7 +2440,6 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
 		 */
 		if (!(scb->flags & TCPCB_FLAG_SYN)) {
 			acked |= FLAG_DATA_ACKED;
-			++pkts_acked;
 		} else {
 			acked |= FLAG_SYN_ACKED;
 			tp->retrans_stamp = 0;
@@ -2481,12 +2483,17 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
 	}
 
 	if (acked&FLAG_ACKED) {
+		u32 pkts_acked = prior_packets - tp->packets_out;
 		const struct tcp_congestion_ops *ca_ops
 			= inet_csk(sk)->icsk_ca_ops;
 
 		tcp_ack_update_rtt(sk, acked, seq_rtt);
 		tcp_ack_packets_out(sk);
 
+		/* Is the ACK triggering packet unambiguous? */
+		if (acked & FLAG_RETRANS_DATA_ACKED)
+			last_ackt = net_invalid_timestamp();
+
 		if (ca_ops->pkts_acked)
 			ca_ops->pkts_acked(sk, pkts_acked, last_ackt);
 	}
@@ -2932,6 +2939,7 @@ void tcp_parse_options(struct sk_buff *skb, struct tcp_options_received *opt_rx,
 					   opt_rx->sack_ok) {
 						TCP_SKB_CB(skb)->sacked = (ptr - 2) - (unsigned char *)th;
 					}
+					break;
 #ifdef CONFIG_TCP_MD5SIG
 				case TCPOPT_MD5SIG:
 					/*