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Back out r242262. The simplified window change/update logic wasn't

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complete and ready for production use.

PR:	kern/173309
This commit is contained in:
Andre Oppermann 2012-11-05 09:13:06 +00:00
parent bc919a54b2
commit 60ee3bb213
1 changed files with 16 additions and 47 deletions
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63
sys/netinet/tcp_input.c
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@ -1727,7 +1727,7 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
* 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 tcphdr *th, struct socket *so,
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 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
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 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
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 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
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