From 9fffe2524dd695053a4ad0b6fa7428f3023b33e6 Mon Sep 17 00:00:00 2001 From: hiren Date: Tue, 6 Oct 2015 07:46:19 +0000 Subject: [PATCH] Add a comment specifying how we implement rfc3042. Differential Revision: D3746 MFC after: 1 week Sponsored by: Limelight Networks --- sys/netinet/tcp_input.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c index 5d2cac493973..b6ea859de310 100644 --- a/sys/netinet/tcp_input.c +++ b/sys/netinet/tcp_input.c @@ -2536,6 +2536,16 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so, tp->snd_nxt = onxt; goto drop; } else if (V_tcp_do_rfc3042) { + /* + * Process first and second duplicate + * ACKs. Each indicates a segment + * leaving the network, creating room + * for more. Make sure we can send a + * packet on reception of each duplicate + * ACK by increasing snd_cwnd by one + * segment. Restore the original + * snd_cwnd after packet transmission. + */ cc_ack_received(tp, th, CC_DUPACK); u_long oldcwnd = tp->snd_cwnd; tcp_seq oldsndmax = tp->snd_max;