Author: andre
Date: Mon Nov 5 09:13:06 2012
New Revision: 242601
URL: http://svnweb.freebsd.org/changeset/base/242601
Log:
Back out r242262. The simplified window change/update logic wasn't
complete and ready for production use.
PR: kern/173309
Modified:
head/sys/netinet/tcp_input.c
Modified: head/sys/netinet/tcp_input.c
==============================================================================
--- head/sys/netinet/tcp_input.c Mon Nov 5 07:44:00 2012
(r242600)
+++ head/sys/netinet/tcp_input.c Mon Nov 5 09:13:06 2012
(r242601)
@@ -1727,7 +1727,7 @@ tcp_do_segment(struct mbuf *m, struct tc
* Pull snd_wl1 up to prevent seq wrap relative to
* th_seq.
*/
- tp->snd_wl1 = th->th_seq + tlen;
+ tp->snd_wl1 = th->th_seq;
/*
* Pull rcv_up up to prevent seq wrap relative to
* rcv_nxt.
@@ -2340,6 +2340,7 @@ tcp_do_segment(struct mbuf *m, struct tc
if (tlen == 0 && (thflags & TH_FIN) == 0)
(void) tcp_reass(tp, (struct tcphdr *)0, 0,
(struct mbuf *)0);
+ tp->snd_wl1 = th->th_seq - 1;
/* FALLTHROUGH */
/*
@@ -2650,10 +2651,12 @@ process_ACK:
SOCKBUF_LOCK(&so->so_snd);
if (acked > so->so_snd.sb_cc) {
+ tp->snd_wnd -= so->so_snd.sb_cc;
sbdrop_locked(&so->so_snd, (int)so->so_snd.sb_cc);
ourfinisacked = 1;
} else {
sbdrop_locked(&so->so_snd, acked);
+ tp->snd_wnd -= acked;
ourfinisacked = 0;
}
/* NB: sowwakeup_locked() does an implicit unlock. */
@@ -2743,56 +2746,24 @@ step6:
INP_WLOCK_ASSERT(tp->t_inpcb);
/*
- * Window update acceptance logic. We have to be careful not
- * to accept window updates from old segments in the presence
- * of reordering or duplication.
- *
- * A window update is valid when:
- * - the segment ACK's new data.
- * - the segment carries new data and its ACK is current.
- * - the segment matches the current SEQ and ACK but increases
- * the window. This is the escape from persist mode, if there
- * data to be sent.
- *
- * XXXAO: The presence of new SACK information would allow to
- * accept window updates during retransmits. We don't have an
- * easy way to test for that the moment.
- *
- * NB: The other side isn't allowed to shrink the window when
- * not sending or acking new data. This behavior is strongly
- * discouraged by RFC793, section 3.7, page 42 anyways.
- *
- * XXXAO: tiwin >= minmss to avoid jitter?
+ * Update window information.
+ * Don't look at window if no ACK: TAC's send garbage on first SYN.
*/
- if ((thflags & TH_ACK) && tiwin != tp->snd_wnd &&
- (SEQ_GT(th->th_ack, tp->snd_wl2) ||
- (th->th_ack == tp->snd_wl2 &&
- (SEQ_GT(th->th_seq + tlen, tp->snd_wl1) ||
- (th->th_seq == tp->snd_wl1 && tlen == 0 && tiwin >
tp->snd_wnd))))) {
-#if 0
- char *s;
- if ((s = tcp_log_addrs(&tp->t_inpcb->inp_inc, th, NULL, NULL)))
{
- log(LOG_DEBUG, "%s; %s: window update %lu -> %lu\n",
- s, __func__, tp->snd_wnd, tiwin);
- free(s, M_TCPLOG);
- }
-#endif
- /* Keep track of pure window updates. */
- if (th->th_seq == tp->snd_wl1 && tlen == 0 &&
- tiwin > tp->snd_wnd)
+ if ((thflags & TH_ACK) &&
+ (SEQ_LT(tp->snd_wl1, th->th_seq) ||
+ (tp->snd_wl1 == th->th_seq && (SEQ_LT(tp->snd_wl2, th->th_ack) ||
+ (tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd))))) {
+ /* keep track of pure window updates */
+ if (tlen == 0 &&
+ tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd)
TCPSTAT_INC(tcps_rcvwinupd);
- /*
- * When the new window is larger, nudge output
- * as we may be able to send more data.
- */
- if (tiwin > tp->snd_wnd)
- needoutput = 1;
tp->snd_wnd = tiwin;
+ tp->snd_wl1 = th->th_seq;
+ tp->snd_wl2 = th->th_ack;
if (tp->snd_wnd > tp->max_sndwnd)
tp->max_sndwnd = tp->snd_wnd;
+ needoutput = 1;
}
- if (SEQ_GT(th->th_ack, tp->snd_wl2))
- tp->snd_wl2 = th->th_ack;
/*
* Process segments with URG.
@@ -2912,8 +2883,6 @@ dodata:
/* XXX */
thflags = tcp_reass(tp, th, &tlen, m);
tp->t_flags |= TF_ACKNOW;
}
- if (SEQ_GT(th->th_seq, tp->snd_wl1))
- tp->snd_wl1 = th->th_seq + tlen;
if (tlen > 0 && (tp->t_flags & TF_SACK_PERMIT))
tcp_update_sack_list(tp, save_start, save_start + tlen);
#if 0
_______________________________________________
svn-src-head@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-head
To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
