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Remove some bogosity from the SYN_SENT case in tcp_do_segment

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and simplify handling of the send/receive window scaling.  No
change in effective behavour.

RFC1323 requires the window field in a SYN (i.e., a <SYN> or
<SYN,ACK>) segment itself never be scaled.

Noticed by:	yar
This commit is contained in:
Andre Oppermann 2007-06-09 21:09:49 +00:00
parent 86a49dea5b
commit 5396d0f8d8
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=170469
1 changed files with 8 additions and 6 deletions
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14
sys/netinet/tcp_input.c
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@ -920,8 +920,7 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
/*
* Unscale the window into a 32-bit value.
* This value is bogus for the TCPS_SYN_SENT state
* and is overwritten later.
* For the SYN_SENT state it is zero.
*/
tiwin = th->th_win << tp->snd_scale;
@ -947,6 +946,8 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
/*
* Process options only when we get SYN/ACK back. The SYN case
* for incoming connections is handled in tcp_syncache.
* According to RFC1323 the window field in a SYN (i.e., a <SYN>
* or <SYN,ACK>) segment itself is never scaled.
* XXX this is traditional behavior, may need to be cleaned up.
*/
if (tp->t_state == TCPS_SYN_SENT && (thflags & TH_SYN)) {
@ -954,16 +955,17 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
(tp->t_flags & TF_REQ_SCALE)) {
tp->t_flags |= TF_RCVD_SCALE;
tp->snd_scale = to.to_wscale;
tp->snd_wnd = th->th_win << tp->snd_scale;
tiwin = tp->snd_wnd;
}
/*
* Initial send window. It will be updated with
* the next incoming segment to the scaled value.
*/
tp->snd_wnd = th->th_win;
if (to.to_flags & TOF_TS) {
tp->t_flags |= TF_RCVD_TSTMP;
tp->ts_recent = to.to_tsval;
tp->ts_recent_age = ticks;
}
/* Initial send window, already scaled. */
tp->snd_wnd = th->th_win;
if (to.to_flags & TOF_MSS)
tcp_mss(tp, to.to_mss);
if ((tp->t_flags & TF_SACK_PERMIT) &&