Author: peter
Date: Tue Jan 28 21:13:15 2014
New Revision: 261244
URL: http://svnweb.freebsd.org/changeset/base/261244
Log:
Adjust r239672 from rrs and r258821 from eadler.
By definition, the very first FIN is not a duplicate. Process it normally
and don't feed it to congestion control as though it were a dupe. Don't
prevent CC from seeing later dupe acks while in a half close state.
Modified:
head/sys/netinet/tcp_input.c
Modified: head/sys/netinet/tcp_input.c
==============================================================================
--- head/sys/netinet/tcp_input.c Tue Jan 28 20:53:33 2014
(r261243)
+++ head/sys/netinet/tcp_input.c Tue Jan 28 21:13:15 2014
(r261244)
@@ -2429,8 +2429,19 @@ tcp_do_segment(struct mbuf *m, struct tc
hhook_run_tcp_est_in(tp, th, &to);
if (SEQ_LEQ(th->th_ack, tp->snd_una)) {
- if (tlen == 0 && tiwin == tp->snd_wnd &&
- !(thflags & TH_FIN)) {
+ if (tlen == 0 && tiwin == tp->snd_wnd) {
+ /*
+ * If this is the first time we've seen a
+ * FIN from the remote, this is not a
+ * duplicate and it needs to be processed
+ * normally. This happens during a
+ * simultaneous close.
+ */
+ if ((thflags & TH_FIN) &&
+ (TCPS_HAVERCVDFIN(tp->t_state) == 0)) {
+ tp->t_dupacks = 0;
+ break;
+ }
TCPSTAT_INC(tcps_rcvdupack);
/*
* If we have outstanding data (other than
@@ -2485,16 +2496,6 @@ tcp_do_segment(struct mbuf *m, struct tc
}
} else
tp->snd_cwnd += tp->t_maxseg;
- if ((thflags & TH_FIN) &&
- (TCPS_HAVERCVDFIN(tp->t_state) ==
0)) {
- /*
- * If its a fin we need to
process
- * it to avoid a race where both
- * sides enter FIN-WAIT and
send FIN|ACK
- * at the same time.
- */
- break;
- }
(void) tcp_output(tp);
goto drop;
} else if (tp->t_dupacks == tcprexmtthresh) {
@@ -2534,16 +2535,6 @@ tcp_do_segment(struct mbuf *m, struct tc
}
tp->snd_nxt = th->th_ack;
tp->snd_cwnd = tp->t_maxseg;
- if ((thflags & TH_FIN) &&
- (TCPS_HAVERCVDFIN(tp->t_state) ==
0)) {
- /*
- * If its a fin we need to
process
- * it to avoid a race where both
- * sides enter FIN-WAIT and
send FIN|ACK
- * at the same time.
- */
- break;
- }
(void) tcp_output(tp);
KASSERT(tp->snd_limited <= 2,
("%s: tp->snd_limited too big",
@@ -2571,16 +2562,6 @@ tcp_do_segment(struct mbuf *m, struct tc
(tp->snd_nxt - tp->snd_una) +
(tp->t_dupacks - tp->snd_limited) *
tp->t_maxseg;
- if ((thflags & TH_FIN) &&
- (TCPS_HAVERCVDFIN(tp->t_state) ==
0)) {
- /*
- * If its a fin we need to
process
- * it to avoid a race where both
- * sides enter FIN-WAIT and
send FIN|ACK
- * at the same time.
- */
- break;
- }
/*
* Only call tcp_output when there
* is new data available to be sent.
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