diff options
Diffstat (limited to 'net/ipv4/tcp_input.c')
| -rw-r--r-- | net/ipv4/tcp_input.c | 35 |
1 files changed, 24 insertions, 11 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 7832d941dbcd..a3d47af01906 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -74,6 +74,7 @@ #include <linux/ipsec.h> #include <asm/unaligned.h> #include <net/netdma.h> +#include <linux/errqueue.h> int sysctl_tcp_timestamps __read_mostly = 1; int sysctl_tcp_window_scaling __read_mostly = 1; @@ -1904,16 +1905,17 @@ void tcp_clear_retrans(struct tcp_sock *tp) tp->sacked_out = 0; } -/* Enter Loss state. If "how" is not zero, forget all SACK information +/* Enter Loss state. If we detect SACK reneging, forget all SACK information * and reset tags completely, otherwise preserve SACKs. If receiver * dropped its ofo queue, we will know this due to reneging detection. */ -void tcp_enter_loss(struct sock *sk, int how) +void tcp_enter_loss(struct sock *sk) { const struct inet_connection_sock *icsk = inet_csk(sk); struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *skb; bool new_recovery = false; + bool is_reneg; /* is receiver reneging on SACKs? */ /* Reduce ssthresh if it has not yet been made inside this window. */ if (icsk->icsk_ca_state <= TCP_CA_Disorder || @@ -1934,7 +1936,11 @@ void tcp_enter_loss(struct sock *sk, int how) tcp_reset_reno_sack(tp); tp->undo_marker = tp->snd_una; - if (how) { + + skb = tcp_write_queue_head(sk); + is_reneg = skb && (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED); + if (is_reneg) { + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPSACKRENEGING); tp->sacked_out = 0; tp->fackets_out = 0; } @@ -1948,7 +1954,7 @@ void tcp_enter_loss(struct sock *sk, int how) tp->undo_marker = 0; TCP_SKB_CB(skb)->sacked &= (~TCPCB_TAGBITS)|TCPCB_SACKED_ACKED; - if (!(TCP_SKB_CB(skb)->sacked&TCPCB_SACKED_ACKED) || how) { + if (!(TCP_SKB_CB(skb)->sacked&TCPCB_SACKED_ACKED) || is_reneg) { TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_ACKED; TCP_SKB_CB(skb)->sacked |= TCPCB_LOST; tp->lost_out += tcp_skb_pcount(skb); @@ -1981,19 +1987,21 @@ void tcp_enter_loss(struct sock *sk, int how) * remembered SACKs do not reflect real state of receiver i.e. * receiver _host_ is heavily congested (or buggy). * - * Do processing similar to RTO timeout. + * To avoid big spurious retransmission bursts due to transient SACK + * scoreboard oddities that look like reneging, we give the receiver a + * little time (max(RTT/2, 10ms)) to send us some more ACKs that will + * restore sanity to the SACK scoreboard. If the apparent reneging + * persists until this RTO then we'll clear the SACK scoreboard. */ static bool tcp_check_sack_reneging(struct sock *sk, int flag) { if (flag & FLAG_SACK_RENEGING) { - struct inet_connection_sock *icsk = inet_csk(sk); - NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPSACKRENEGING); + struct tcp_sock *tp = tcp_sk(sk); + unsigned long delay = max(usecs_to_jiffies(tp->srtt_us >> 4), + msecs_to_jiffies(10)); - tcp_enter_loss(sk, 1); - icsk->icsk_retransmits++; - tcp_retransmit_skb(sk, tcp_write_queue_head(sk)); inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, - icsk->icsk_rto, TCP_RTO_MAX); + delay, TCP_RTO_MAX); return true; } return false; @@ -3099,6 +3107,11 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets, tp->retrans_stamp = 0; } + if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_ACK_TSTAMP) && + between(skb_shinfo(skb)->tskey, prior_snd_una, + tp->snd_una + 1)) + __skb_tstamp_tx(skb, NULL, sk, SCM_TSTAMP_ACK); + if (!fully_acked) break; |