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Split the overloaded variable 'win' into two for their specific purposes:

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recwin and sendwin.  This removes a big source of confusion and makes
following the code much easier.

Reviewed by:	sam (mentor)
Obtained from:	DragonFlyBSD rev 1.6 (hsu)
This commit is contained in:
Andre Oppermann 2004-01-22 23:22:14 +00:00
parent 1ddba8d63e
commit 201d185b69
1 changed files with 22 additions and 21 deletions
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43
sys/netinet/tcp_output.c
View File

@ -113,7 +113,7 @@ int
tcp_output(struct tcpcb *tp)
{
struct socket *so = tp->t_inpcb->inp_socket;
long len, win;
long len, recwin, sendwin;
int off, flags, error;
struct mbuf *m;
struct ip *ip = NULL;
@ -173,8 +173,8 @@ tcp_output(struct tcpcb *tp)
again:
sendalot = 0;
off = tp->snd_nxt - tp->snd_una;
win = min(tp->snd_wnd, tp->snd_cwnd);
win = min(win, tp->snd_bwnd);
sendwin = min(tp->snd_wnd, tp->snd_cwnd);
sendwin = min(sendwin, tp->snd_bwnd);
flags = tcp_outflags[tp->t_state];
/*
@ -193,7 +193,7 @@ again:
* and go to transmit state.
*/
if (tp->t_force) {
if (win == 0) {
if (sendwin == 0) {
/*
* If we still have some data to send, then
* clear the FIN bit. Usually this would
@ -212,7 +212,7 @@ again:
*/
if (off < so->so_snd.sb_cc)
flags &= ~TH_FIN;
win = 1;
sendwin = 1;
} else {
callout_stop(tp->tt_persist);
tp->t_rxtshift = 0;
@ -222,7 +222,7 @@ again:
/*
* If snd_nxt == snd_max and we have transmitted a FIN, the
* offset will be > 0 even if so_snd.sb_cc is 0, resulting in
* a negative length. This can also occur when tcp opens up
* a negative length. This can also occur when TCP opens up
* its congestion window while receiving additional duplicate
* acks after fast-retransmit because TCP will reset snd_nxt
* to snd_max after the fast-retransmit.
@ -231,7 +231,7 @@ again:
* be set to snd_una, the offset will be 0, and the length may
* wind up 0.
*/
len = (long)ulmin(so->so_snd.sb_cc, win) - off;
len = (long)ulmin(so->so_snd.sb_cc, sendwin) - off;
/*
@ -274,7 +274,7 @@ again:
* close completely, just wait for an ACK.
*/
len = 0;
if (win == 0) {
if (sendwin == 0) {
callout_stop(tp->tt_rexmt);
tp->t_rxtshift = 0;
tp->snd_nxt = tp->snd_una;
@ -295,7 +295,7 @@ again:
if (SEQ_LT(tp->snd_nxt + len, tp->snd_una + so->so_snd.sb_cc))
flags &= ~TH_FIN;
win = sbspace(&so->so_rcv);
recwin = sbspace(&so->so_rcv);
/*
* Sender silly window avoidance. We transmit under the following
@ -341,13 +341,13 @@ again:
* window, then want to send a window update to peer.
* Skip this if the connection is in T/TCP half-open state.
*/
if (win > 0 && !(tp->t_flags & TF_NEEDSYN)) {
if (recwin > 0 && !(tp->t_flags & TF_NEEDSYN)) {
/*
* "adv" is the amount we can increase the window,
* taking into account that we are limited by
* TCP_MAXWIN << tp->rcv_scale.
*/
long adv = min(win, (long)TCP_MAXWIN << tp->rcv_scale) -
long adv = min(recwin, (long)TCP_MAXWIN << tp->rcv_scale) -
(tp->rcv_adv - tp->rcv_nxt);
if (adv >= (long) (2 * tp->t_maxseg))
@ -720,13 +720,14 @@ send:
* Calculate receive window. Don't shrink window,
* but avoid silly window syndrome.
*/
if (win < (long)(so->so_rcv.sb_hiwat / 4) && win < (long)tp->t_maxseg)
win = 0;
if (win < (long)(tp->rcv_adv - tp->rcv_nxt))
win = (long)(tp->rcv_adv - tp->rcv_nxt);
if (win > (long)TCP_MAXWIN << tp->rcv_scale)
win = (long)TCP_MAXWIN << tp->rcv_scale;
th->th_win = htons((u_short) (win>>tp->rcv_scale));
if (recwin < (long)(so->so_rcv.sb_hiwat / 4) &&
recwin < (long)tp->t_maxseg)
recwin = 0;
if (recwin < (long)(tp->rcv_adv - tp->rcv_nxt))
recwin = (long)(tp->rcv_adv - tp->rcv_nxt);
if (recwin > (long)TCP_MAXWIN << tp->rcv_scale)
recwin = (long)TCP_MAXWIN << tp->rcv_scale;
th->th_win = htons((u_short) (recwin >> tp->rcv_scale));
/*
@ -737,7 +738,7 @@ send:
* to read more data then can be buffered prior to transmitting on
* the connection.
*/
if (win == 0)
if (recwin == 0)
tp->t_flags |= TF_RXWIN0SENT;
else
tp->t_flags &= ~TF_RXWIN0SENT;
@ -957,8 +958,8 @@ out:
* then remember the size of the advertised window.
* Any pending ACK has now been sent.
*/
if (win > 0 && SEQ_GT(tp->rcv_nxt+win, tp->rcv_adv))
tp->rcv_adv = tp->rcv_nxt + win;
if (recwin > 0 && SEQ_GT(tp->rcv_nxt + recwin, tp->rcv_adv))
tp->rcv_adv = tp->rcv_nxt + recwin;
tp->last_ack_sent = tp->rcv_nxt;
tp->t_flags &= ~(TF_ACKNOW | TF_DELACK);
if (callout_active(tp->tt_delack))