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Diffstat (limited to 'net/ipv4/tcp_input.c')
-rw-r--r--net/ipv4/tcp_input.c45
1 files changed, 28 insertions, 17 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index eda4f4a233f..b54d9d37b63 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -66,6 +66,7 @@
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/sysctl.h>
+#include <net/dst.h>
#include <net/tcp.h>
#include <net/inet_common.h>
#include <linux/ipsec.h>
@@ -113,8 +114,6 @@ int sysctl_tcp_abc __read_mostly;
#define FLAG_FORWARD_PROGRESS (FLAG_ACKED|FLAG_DATA_SACKED)
#define FLAG_ANY_PROGRESS (FLAG_FORWARD_PROGRESS|FLAG_SND_UNA_ADVANCED)
-#define IsSackFrto() (sysctl_tcp_frto == 0x2)
-
#define TCP_REMNANT (TCP_FLAG_FIN|TCP_FLAG_URG|TCP_FLAG_SYN|TCP_FLAG_PSH)
#define TCP_HP_BITS (~(TCP_RESERVED_BITS|TCP_FLAG_PSH))
@@ -605,7 +604,7 @@ static u32 tcp_rto_min(struct sock *sk)
u32 rto_min = TCP_RTO_MIN;
if (dst && dst_metric_locked(dst, RTAX_RTO_MIN))
- rto_min = dst->metrics[RTAX_RTO_MIN - 1];
+ rto_min = dst_metric(dst, RTAX_RTO_MIN);
return rto_min;
}
@@ -769,7 +768,7 @@ void tcp_update_metrics(struct sock *sk)
dst->metrics[RTAX_RTTVAR - 1] = m;
else
dst->metrics[RTAX_RTTVAR-1] -=
- (dst->metrics[RTAX_RTTVAR-1] - m)>>2;
+ (dst_metric(dst, RTAX_RTTVAR) - m)>>2;
}
if (tp->snd_ssthresh >= 0xFFFF) {
@@ -788,21 +787,21 @@ void tcp_update_metrics(struct sock *sk)
dst->metrics[RTAX_SSTHRESH-1] =
max(tp->snd_cwnd >> 1, tp->snd_ssthresh);
if (!dst_metric_locked(dst, RTAX_CWND))
- dst->metrics[RTAX_CWND-1] = (dst->metrics[RTAX_CWND-1] + tp->snd_cwnd) >> 1;
+ dst->metrics[RTAX_CWND-1] = (dst_metric(dst, RTAX_CWND) + tp->snd_cwnd) >> 1;
} else {
/* Else slow start did not finish, cwnd is non-sense,
ssthresh may be also invalid.
*/
if (!dst_metric_locked(dst, RTAX_CWND))
- dst->metrics[RTAX_CWND-1] = (dst->metrics[RTAX_CWND-1] + tp->snd_ssthresh) >> 1;
- if (dst->metrics[RTAX_SSTHRESH-1] &&
+ dst->metrics[RTAX_CWND-1] = (dst_metric(dst, RTAX_CWND) + tp->snd_ssthresh) >> 1;
+ if (dst_metric(dst, RTAX_SSTHRESH) &&
!dst_metric_locked(dst, RTAX_SSTHRESH) &&
- tp->snd_ssthresh > dst->metrics[RTAX_SSTHRESH-1])
+ tp->snd_ssthresh > dst_metric(dst, RTAX_SSTHRESH))
dst->metrics[RTAX_SSTHRESH-1] = tp->snd_ssthresh;
}
if (!dst_metric_locked(dst, RTAX_REORDERING)) {
- if (dst->metrics[RTAX_REORDERING-1] < tp->reordering &&
+ if (dst_metric(dst, RTAX_REORDERING) < tp->reordering &&
tp->reordering != sysctl_tcp_reordering)
dst->metrics[RTAX_REORDERING-1] = tp->reordering;
}
@@ -1685,6 +1684,11 @@ static inline void tcp_reset_reno_sack(struct tcp_sock *tp)
tp->sacked_out = 0;
}
+static int tcp_is_sackfrto(const struct tcp_sock *tp)
+{
+ return (sysctl_tcp_frto == 0x2) && !tcp_is_reno(tp);
+}
+
/* F-RTO can only be used if TCP has never retransmitted anything other than
* head (SACK enhanced variant from Appendix B of RFC4138 is more robust here)
*/
@@ -1701,7 +1705,7 @@ int tcp_use_frto(struct sock *sk)
if (icsk->icsk_mtup.probe_size)
return 0;
- if (IsSackFrto())
+ if (tcp_is_sackfrto(tp))
return 1;
/* Avoid expensive walking of rexmit queue if possible */
@@ -1791,7 +1795,7 @@ void tcp_enter_frto(struct sock *sk)
/* Earlier loss recovery underway (see RFC4138; Appendix B).
* The last condition is necessary at least in tp->frto_counter case.
*/
- if (IsSackFrto() && (tp->frto_counter ||
+ if (tcp_is_sackfrto(tp) && (tp->frto_counter ||
((1 << icsk->icsk_ca_state) & (TCPF_CA_Recovery|TCPF_CA_Loss))) &&
after(tp->high_seq, tp->snd_una)) {
tp->frto_highmark = tp->high_seq;
@@ -1838,9 +1842,16 @@ static void tcp_enter_frto_loss(struct sock *sk, int allowed_segments, int flag)
TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS;
}
- /* Don't lost mark skbs that were fwd transmitted after RTO */
- if (!(TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED) &&
- !after(TCP_SKB_CB(skb)->end_seq, tp->frto_highmark)) {
+ /* Marking forward transmissions that were made after RTO lost
+ * can cause unnecessary retransmissions in some scenarios,
+ * SACK blocks will mitigate that in some but not in all cases.
+ * We used to not mark them but it was causing break-ups with
+ * receivers that do only in-order receival.
+ *
+ * TODO: we could detect presence of such receiver and select
+ * different behavior per flow.
+ */
+ if (!(TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)) {
TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
tp->lost_out += tcp_skb_pcount(skb);
}
@@ -1856,7 +1867,7 @@ static void tcp_enter_frto_loss(struct sock *sk, int allowed_segments, int flag)
tp->reordering = min_t(unsigned int, tp->reordering,
sysctl_tcp_reordering);
tcp_set_ca_state(sk, TCP_CA_Loss);
- tp->high_seq = tp->frto_highmark;
+ tp->high_seq = tp->snd_nxt;
TCP_ECN_queue_cwr(tp);
tcp_clear_retrans_hints_partial(tp);
@@ -2478,7 +2489,7 @@ static void tcp_try_to_open(struct sock *sk, int flag)
tcp_verify_left_out(tp);
- if (tp->retrans_out == 0)
+ if (!tp->frto_counter && tp->retrans_out == 0)
tp->retrans_stamp = 0;
if (flag & FLAG_ECE)
@@ -3123,7 +3134,7 @@ static int tcp_process_frto(struct sock *sk, int flag)
return 1;
}
- if (!IsSackFrto() || tcp_is_reno(tp)) {
+ if (!tcp_is_sackfrto(tp)) {
/* RFC4138 shortcoming in step 2; should also have case c):
* ACK isn't duplicate nor advances window, e.g., opposite dir
* data, winupdate