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authorIlpo Järvinen <ilpo.jarvinen@helsinki.fi>2007-09-20 14:34:38 -0400
committerDavid S. Miller <davem@sunset.davemloft.net>2007-10-10 19:52:11 -0400
commit009a2e3e4ec395a290b9e4c7c9ff99296fd6b7d8 (patch)
tree65aba1ad44fb5519a0a043b7a97d76242b4d663f /net/ipv4/tcp_input.c
parent7c46a03e67d11d917d6c3dbf501b465b2ca97a6f (diff)
[TCP] FRTO: Improve interoperability with other undo_marker users
Basically this change enables it, previously other undo_marker users were left with nothing. Reverse undo_marker logic completely to get it set right in CA_Loss. On the other hand, when spurious RTO is detected, clear it. Clearing might be too heavy for some scenarios but seems safe enough starting point for now and shouldn't have much effect except in majority of cases (if in any). By adding a new FLAG_ we avoid looping through write_queue when RTO occurs. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_input.c')
-rw-r--r--net/ipv4/tcp_input.c42
1 files changed, 27 insertions, 15 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 8fe754be8076..0feb10935be1 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -104,6 +104,7 @@ int sysctl_tcp_abc __read_mostly;
104#define FLAG_ONLY_ORIG_SACKED 0x200 /* SACKs only non-rexmit sent before RTO */ 104#define FLAG_ONLY_ORIG_SACKED 0x200 /* SACKs only non-rexmit sent before RTO */
105#define FLAG_SND_UNA_ADVANCED 0x400 /* Snd_una was changed (!= FLAG_DATA_ACKED) */ 105#define FLAG_SND_UNA_ADVANCED 0x400 /* Snd_una was changed (!= FLAG_DATA_ACKED) */
106#define FLAG_DSACKING_ACK 0x800 /* SACK blocks contained DSACK info */ 106#define FLAG_DSACKING_ACK 0x800 /* SACK blocks contained DSACK info */
107#define FLAG_NONHEAD_RETRANS_ACKED 0x1000 /* Non-head rexmitted data was ACKed */
107 108
108#define FLAG_ACKED (FLAG_DATA_ACKED|FLAG_SYN_ACKED) 109#define FLAG_ACKED (FLAG_DATA_ACKED|FLAG_SYN_ACKED)
109#define FLAG_NOT_DUP (FLAG_DATA|FLAG_WIN_UPDATE|FLAG_ACKED) 110#define FLAG_NOT_DUP (FLAG_DATA|FLAG_WIN_UPDATE|FLAG_ACKED)
@@ -1594,6 +1595,8 @@ void tcp_enter_frto(struct sock *sk)
1594 tp->undo_retrans = 0; 1595 tp->undo_retrans = 0;
1595 1596
1596 skb = tcp_write_queue_head(sk); 1597 skb = tcp_write_queue_head(sk);
1598 if (TCP_SKB_CB(skb)->sacked & TCPCB_RETRANS)
1599 tp->undo_marker = 0;
1597 if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_RETRANS) { 1600 if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_RETRANS) {
1598 TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS; 1601 TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS;
1599 tp->retrans_out -= tcp_skb_pcount(skb); 1602 tp->retrans_out -= tcp_skb_pcount(skb);
@@ -1643,6 +1646,8 @@ static void tcp_enter_frto_loss(struct sock *sk, int allowed_segments, int flag)
1643 /* ...enter this if branch just for the first segment */ 1646 /* ...enter this if branch just for the first segment */
1644 flag |= FLAG_DATA_ACKED; 1647 flag |= FLAG_DATA_ACKED;
1645 } else { 1648 } else {
1649 if (TCP_SKB_CB(skb)->sacked & TCPCB_RETRANS)
1650 tp->undo_marker = 0;
1646 TCP_SKB_CB(skb)->sacked &= ~(TCPCB_LOST|TCPCB_SACKED_RETRANS); 1651 TCP_SKB_CB(skb)->sacked &= ~(TCPCB_LOST|TCPCB_SACKED_RETRANS);
1647 } 1652 }
1648 1653
@@ -1658,7 +1663,6 @@ static void tcp_enter_frto_loss(struct sock *sk, int allowed_segments, int flag)
1658 tp->snd_cwnd = tcp_packets_in_flight(tp) + allowed_segments; 1663 tp->snd_cwnd = tcp_packets_in_flight(tp) + allowed_segments;
1659 tp->snd_cwnd_cnt = 0; 1664 tp->snd_cwnd_cnt = 0;
1660 tp->snd_cwnd_stamp = tcp_time_stamp; 1665 tp->snd_cwnd_stamp = tcp_time_stamp;
1661 tp->undo_marker = 0;
1662 tp->frto_counter = 0; 1666 tp->frto_counter = 0;
1663 1667
1664 tp->reordering = min_t(unsigned int, tp->reordering, 1668 tp->reordering = min_t(unsigned int, tp->reordering,
@@ -2584,20 +2588,6 @@ static int tcp_clean_rtx_queue(struct sock *sk, s32 *seq_rtt_p)
2584 end_seq = scb->end_seq; 2588 end_seq = scb->end_seq;
2585 } 2589 }
2586 2590
2587 /* Initial outgoing SYN's get put onto the write_queue
2588 * just like anything else we transmit. It is not
2589 * true data, and if we misinform our callers that
2590 * this ACK acks real data, we will erroneously exit
2591 * connection startup slow start one packet too
2592 * quickly. This is severely frowned upon behavior.
2593 */
2594 if (!(scb->flags & TCPCB_FLAG_SYN)) {
2595 flag |= FLAG_DATA_ACKED;
2596 } else {
2597 flag |= FLAG_SYN_ACKED;
2598 tp->retrans_stamp = 0;
2599 }
2600
2601 /* MTU probing checks */ 2591 /* MTU probing checks */
2602 if (fully_acked && icsk->icsk_mtup.probe_size && 2592 if (fully_acked && icsk->icsk_mtup.probe_size &&
2603 !after(tp->mtu_probe.probe_seq_end, scb->end_seq)) { 2593 !after(tp->mtu_probe.probe_seq_end, scb->end_seq)) {
@@ -2610,6 +2600,9 @@ static int tcp_clean_rtx_queue(struct sock *sk, s32 *seq_rtt_p)
2610 tp->retrans_out -= packets_acked; 2600 tp->retrans_out -= packets_acked;
2611 flag |= FLAG_RETRANS_DATA_ACKED; 2601 flag |= FLAG_RETRANS_DATA_ACKED;
2612 seq_rtt = -1; 2602 seq_rtt = -1;
2603 if ((flag & FLAG_DATA_ACKED) ||
2604 (packets_acked > 1))
2605 flag |= FLAG_NONHEAD_RETRANS_ACKED;
2613 } else if (seq_rtt < 0) { 2606 } else if (seq_rtt < 0) {
2614 seq_rtt = now - scb->when; 2607 seq_rtt = now - scb->when;
2615 if (fully_acked) 2608 if (fully_acked)
@@ -2631,6 +2624,20 @@ static int tcp_clean_rtx_queue(struct sock *sk, s32 *seq_rtt_p)
2631 } 2624 }
2632 tp->packets_out -= packets_acked; 2625 tp->packets_out -= packets_acked;
2633 2626
2627 /* Initial outgoing SYN's get put onto the write_queue
2628 * just like anything else we transmit. It is not
2629 * true data, and if we misinform our callers that
2630 * this ACK acks real data, we will erroneously exit
2631 * connection startup slow start one packet too
2632 * quickly. This is severely frowned upon behavior.
2633 */
2634 if (!(scb->flags & TCPCB_FLAG_SYN)) {
2635 flag |= FLAG_DATA_ACKED;
2636 } else {
2637 flag |= FLAG_SYN_ACKED;
2638 tp->retrans_stamp = 0;
2639 }
2640
2634 if (!fully_acked) 2641 if (!fully_acked)
2635 break; 2642 break;
2636 2643
@@ -2852,6 +2859,10 @@ static int tcp_process_frto(struct sock *sk, int flag)
2852 if (flag&FLAG_DATA_ACKED) 2859 if (flag&FLAG_DATA_ACKED)
2853 inet_csk(sk)->icsk_retransmits = 0; 2860 inet_csk(sk)->icsk_retransmits = 0;
2854 2861
2862 if ((flag & FLAG_NONHEAD_RETRANS_ACKED) ||
2863 ((tp->frto_counter >= 2) && (flag & FLAG_RETRANS_DATA_ACKED)))
2864 tp->undo_marker = 0;
2865
2855 if (!before(tp->snd_una, tp->frto_highmark)) { 2866 if (!before(tp->snd_una, tp->frto_highmark)) {
2856 tcp_enter_frto_loss(sk, (tp->frto_counter == 1 ? 2 : 3), flag); 2867 tcp_enter_frto_loss(sk, (tp->frto_counter == 1 ? 2 : 3), flag);
2857 return 1; 2868 return 1;
@@ -2916,6 +2927,7 @@ static int tcp_process_frto(struct sock *sk, int flag)
2916 break; 2927 break;
2917 } 2928 }
2918 tp->frto_counter = 0; 2929 tp->frto_counter = 0;
2930 tp->undo_marker = 0;
2919 } 2931 }
2920 return 0; 2932 return 0;
2921} 2933}