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When doing TSO subtract hdrlen from TCP_MAXWIN to prevent ip->ip_len

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from wrapping when we generate a maximally sized packet for later
segmentation.

Noticed by:	gallatin
Sponsored by:	TCP/IP Optimization Fundraise 2005
This commit is contained in:
andre 2006-09-15 16:08:09 +00:00
parent 8daf570879
commit e168227ed2
1 changed files with 7 additions and 5 deletions
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12
sys/netinet/tcp_output.c
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@ -730,16 +730,18 @@ tcp_output(struct tcpcb *tp)
* Clear the FIN bit because we cut off the tail of
* the segment.
*
* When doing TSO limit a burst to TCP_MAXWIN and set the
* flag to continue sending and prevent the last segment
* from being fractional thus making them all equal sized.
* When doing TSO limit a burst to TCP_MAXWIN minus the
* IP, TCP and Options length to keep ip->ip_len from
* overflowing. Prevent the last segment from being
* fractional thus making them all equal sized and set
* the flag to continue sending.
*/
if (len + optlen + ipoptlen > tp->t_maxopd) {
flags &= ~TH_FIN;
if (tso) {
if (len > TCP_MAXWIN) {
len = TCP_MAXWIN - TCP_MAXWIN %
(tp->t_maxopd - optlen);
len = TCP_MAXWIN - hdrlen;
len = len - (len % (tp->t_maxopd - optlen));
sendalot = 1;
} else if (tp->t_flags & TF_NEEDFIN)
sendalot = 1;