From 191ae5bfa99f9b639657a8d7845e4b4bcf33ece8 Mon Sep 17 00:00:00 2001 From: Michael Tuexen Date: Tue, 3 Sep 2019 19:48:02 +0000 Subject: [PATCH] Fix two TCP RACK issues: * Convert the TCP delayed ACK timer from ms to ticks as required. This fixes the timer on platforms with hz != 1000. * Don't delay acknowledgements which report duplicate data using DSACKs. Reviewed by: rrs@ MFC after: 1 week Sponsored by: Netflix, Inc. Differential Revision: https://reviews.freebsd.org/D21512 --- sys/netinet/tcp_stacks/rack.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/sys/netinet/tcp_stacks/rack.c b/sys/netinet/tcp_stacks/rack.c index 1f0aebe9f89..39f81a2f5d2 100644 --- a/sys/netinet/tcp_stacks/rack.c +++ b/sys/netinet/tcp_stacks/rack.c @@ -1790,6 +1790,11 @@ rack_drop_checks(struct tcpopt *to, struct mbuf *m, struct tcphdr *th, struct tc */ tcp_update_sack_list(tp, th->th_seq, th->th_seq + todrop); + /* + * ACK now, as the next in-sequence segment + * will clear the DSACK block again + */ + tp->t_flags |= TF_ACKNOW; } *drop_hdrlen += todrop; /* drop from the top afterwards */ th->th_seq += todrop; @@ -2338,7 +2343,7 @@ rack_start_hpts_timer(struct tcp_rack *rack, struct tcpcb *tp, uint32_t cts, int } hpts_timeout = rack_timer_start(tp, rack, cts); if (tp->t_flags & TF_DELACK) { - delayed_ack = tcp_delacktime; + delayed_ack = TICKS_2_MSEC(tcp_delacktime); rack->r_ctl.rc_hpts_flags |= PACE_TMR_DELACK; } if (delayed_ack && ((hpts_timeout == 0) ||