diff options
| -rw-r--r-- | include/net/tcp.h | 2 | ||||
| -rw-r--r-- | net/ipv4/tcp_input.c | 25 |
2 files changed, 22 insertions, 5 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h index 572a77bb690..7fd6b77519c 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -341,7 +341,7 @@ extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb, extern int tcp_child_process(struct sock *parent, struct sock *child, struct sk_buff *skb); -extern int tcp_use_frto(const struct sock *sk); +extern int tcp_use_frto(struct sock *sk); extern void tcp_enter_frto(struct sock *sk); extern void tcp_enter_loss(struct sock *sk, int how); extern void tcp_clear_retrans(struct tcp_sock *tp); diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 723cee63791..a283fc12186 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -1239,14 +1239,31 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_ /* F-RTO can only be used if these conditions are satisfied: * - there must be some unsent new data * - the advertised window should allow sending it + * - TCP has never retransmitted anything other than head */ -int tcp_use_frto(const struct sock *sk) +int tcp_use_frto(struct sock *sk) { const struct tcp_sock *tp = tcp_sk(sk); + struct sk_buff *skb; + + if (!sysctl_tcp_frto || !sk->sk_send_head || + after(TCP_SKB_CB(sk->sk_send_head)->end_seq, + tp->snd_una + tp->snd_wnd)) + return 0; - return (sysctl_tcp_frto && sk->sk_send_head && - !after(TCP_SKB_CB(sk->sk_send_head)->end_seq, - tp->snd_una + tp->snd_wnd)); + /* Avoid expensive walking of rexmit queue if possible */ + if (tp->retrans_out > 1) + return 0; + + skb = skb_peek(&sk->sk_write_queue)->next; /* Skips head */ + sk_stream_for_retrans_queue_from(skb, sk) { + if (TCP_SKB_CB(skb)->sacked&TCPCB_RETRANS) + return 0; + /* Short-circuit when first non-SACKed skb has been checked */ + if (!(TCP_SKB_CB(skb)->sacked&TCPCB_SACKED_ACKED)) + break; + } + return 1; } /* RTO occurred, but do not yet enter Loss state. Instead, defer RTO |