diff options
Diffstat (limited to 'net/ipv4/tcp_input.c')
-rw-r--r-- | net/ipv4/tcp_input.c | 45 |
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 |