[src/trunk]: src/sys/netinet Fix a problem discovered by the snd_recover upda...

[thorpej <thorpej%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/b93f1f1764f5
branches:  trunk
changeset: 475804:b93f1f1764f5
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Thu Aug 26 00:04:30 1999 +0000

description:
Fix a problem discovered by the snd_recover update fix.  A bit of the
New Reno fast recovery code was being executed even when New Reno was
disabled, resulting in an unfortunate interaction with the traditional
fast recovery code, the end resulting being that the very condition
that would trigger the traditional fast recovery mechanism caused fast
recovery to be disabled!

Problem reported by Ted Lemon, and some analytical help from Charles Hannum.

diffstat:

 sys/netinet/tcp_input.c |  17 +++++++++--------
 1 files changed, 9 insertions(+), 8 deletions(-)

diffs (56 lines):

diff -r ec513093a408 -r b93f1f1764f5 sys/netinet/tcp_input.c
--- a/sys/netinet/tcp_input.c   Wed Aug 25 23:23:33 1999 +0000
+++ b/sys/netinet/tcp_input.c   Thu Aug 26 00:04:30 1999 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: tcp_input.c,v 1.93 1999/08/25 15:23:12 itojun Exp $    */
+/*     $NetBSD: tcp_input.c,v 1.94 1999/08/26 00:04:30 thorpej Exp $   */
 
 /*
 %%% portions-copyright-nrl-95
@@ -1579,7 +1579,7 @@
                                        u_int win =
                                            min(tp->snd_wnd, tp->snd_cwnd) / 
                                            2 / tp->t_segsz;
-                                       if (SEQ_LT(th->th_ack,
+                                       if (tcp_do_newreno && SEQ_LT(th->th_ack,
                                            tp->snd_recover)) {
                                                /*
                                                 * False fast retransmit after
@@ -1618,13 +1618,13 @@
                 * If the congestion window was inflated to account
                 * for the other side's cached packets, retract it.
                 */
-               if (!tcp_do_newreno) {
+               if (tcp_do_newreno == 0) {
                        if (tp->t_dupacks >= tcprexmtthresh &&
                            tp->snd_cwnd > tp->snd_ssthresh)
                                tp->snd_cwnd = tp->snd_ssthresh;
                        tp->t_dupacks = 0;
-               } else if (tp->t_dupacks >= tcprexmtthresh
-                   && !tcp_newreno(tp, th)) {
+               } else if (tp->t_dupacks >= tcprexmtthresh &&
+                          tcp_newreno(tp, th) == 0) {
                        tp->snd_cwnd = tp->snd_ssthresh;
                        /*
                         * Window inflation should have left us with approx.
@@ -1634,7 +1634,7 @@
                         */
                        if (SEQ_SUB(tp->snd_max, th->th_ack) < tp->snd_ssthresh)
                                tp->snd_cwnd = SEQ_SUB(tp->snd_max, th->th_ack)
-                                    + tp->t_segsz;
+                                   + tp->t_segsz;
                        tp->t_dupacks = 0;
                }
                if (SEQ_GT(th->th_ack, tp->snd_max)) {
@@ -1685,8 +1685,9 @@
 
                if (cw > tp->snd_ssthresh)
                        incr = incr * incr / cw;
-               if (!tcp_do_newreno || SEQ_GEQ(th->th_ack, tp->snd_recover))
-                       tp->snd_cwnd = min(cw + incr,TCP_MAXWIN<<tp->snd_scale);
+               if (tcp_do_newreno == 0 || SEQ_GEQ(th->th_ack, tp->snd_recover))
+                       tp->snd_cwnd = min(cw + incr,
+                           TCP_MAXWIN << tp->snd_scale);
                }
                if (acked > so->so_snd.sb_cc) {
                        tp->snd_wnd -= so->so_snd.sb_cc;