From e636f8b0104d6622aaaed6aa5ef17dfbf165bc51 Mon Sep 17 00:00:00 2001 From: Yuchung Cheng Date: Thu, 12 Jan 2017 22:11:31 -0800 Subject: [PATCH] tcp: new helper for RACK to detect loss Create a new helper tcp_rack_detect_loss to prepare the upcoming RACK reordering timer patch. Signed-off-by: Yuchung Cheng Signed-off-by: Neal Cardwell Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/tcp.h | 3 +-- net/ipv4/tcp_input.c | 12 ++++++++---- net/ipv4/tcp_recovery.c | 22 +++++++++++++--------- 3 files changed, 22 insertions(+), 15 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index 1da0aa724929..51183bba3835 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1863,8 +1863,7 @@ extern int sysctl_tcp_recovery; /* Use TCP RACK to detect (some) tail and retransmit losses */ #define TCP_RACK_LOST_RETRANS 0x1 -extern int tcp_rack_mark_lost(struct sock *sk); - +extern void tcp_rack_mark_lost(struct sock *sk); extern void tcp_rack_advance(struct tcp_sock *tp, const struct skb_mstamp *xmit_time, u8 sacked); diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index ec6d84363024..bb24b93e64bc 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2865,10 +2865,14 @@ static void tcp_fastretrans_alert(struct sock *sk, const int acked, } /* Use RACK to detect loss */ - if (sysctl_tcp_recovery & TCP_RACK_LOST_RETRANS && - tcp_rack_mark_lost(sk)) { - flag |= FLAG_LOST_RETRANS; - *ack_flag |= FLAG_LOST_RETRANS; + if (sysctl_tcp_recovery & TCP_RACK_LOST_RETRANS) { + u32 prior_retrans = tp->retrans_out; + + tcp_rack_mark_lost(sk); + if (prior_retrans > tp->retrans_out) { + flag |= FLAG_LOST_RETRANS; + *ack_flag |= FLAG_LOST_RETRANS; + } } /* E. Process state. */ diff --git a/net/ipv4/tcp_recovery.c b/net/ipv4/tcp_recovery.c index f38dba5aed7a..7ea0377229c0 100644 --- a/net/ipv4/tcp_recovery.c +++ b/net/ipv4/tcp_recovery.c @@ -32,17 +32,11 @@ static void tcp_rack_mark_skb_lost(struct sock *sk, struct sk_buff *skb) * The current version is only used after recovery starts but can be * easily extended to detect the first loss. */ -int tcp_rack_mark_lost(struct sock *sk) +static void tcp_rack_detect_loss(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *skb; - u32 reo_wnd, prior_retrans = tp->retrans_out; - - if (inet_csk(sk)->icsk_ca_state < TCP_CA_Recovery || !tp->rack.advanced) - return 0; - - /* Reset the advanced flag to avoid unnecessary queue scanning */ - tp->rack.advanced = 0; + u32 reo_wnd; /* To be more reordering resilient, allow min_rtt/4 settling delay * (lower-bounded to 1000uS). We use min_rtt instead of the smoothed @@ -82,7 +76,17 @@ int tcp_rack_mark_lost(struct sock *sk) break; } } - return prior_retrans - tp->retrans_out; +} + +void tcp_rack_mark_lost(struct sock *sk) +{ + struct tcp_sock *tp = tcp_sk(sk); + + if (inet_csk(sk)->icsk_ca_state < TCP_CA_Recovery || !tp->rack.advanced) + return; + /* Reset the advanced flag to avoid unnecessary queue scanning */ + tp->rack.advanced = 0; + tcp_rack_detect_loss(sk); } /* Record the most recently (re)sent time among the (s)acked packets */ -- 2.20.1