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Fix a bug introduced with r182851 splitting tcp_mss() into

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tcp_mss() and tcp_mss_update() so that tcp_mtudisc() could
re-use the same code.

In case we return early and got a metricptr to pass the hostcache
info back to the caller we need to initialize the data to a defined
state (zero it) as tcp_hc_get() would do if there was no hit.
Without that the caller would check on random stack garbage which
could lead to undefined results.

This only affected tcp_mss() if there was no routing entry for the peer,
tcp_mtudisc() was not affected.

MFC after:	2 months (along with r182851)
This commit is contained in:
Bjoern A. Zeeb 2008-11-06 12:33:33 +00:00
parent c3c1513719
commit 6f01cac68a
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=184720
1 changed files with 9 additions and 1 deletions
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10
sys/netinet/tcp_input.c
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@ -2847,8 +2847,16 @@ tcp_mss_update(struct tcpcb *tp, int offer, struct hc_metrics_lite *metricptr)
/*
* No route to sender, stay with default mss and return.
*/
if (maxmtu == 0)
if (maxmtu == 0) {
/*
* In case we return early we need to intialize metrics
* to a defined state as tcp_hc_get() would do for us
* if there was no cache hit.
*/
if (metricptr != NULL)
bzero(metricptr, sizeof(struct hc_metrics_lite));
return;
}
/* Check the interface for TSO capabilities. */
if (mtuflags & CSUM_TSO)