svn commit: r260702 - head/sys/netinet
Alexander V. Chernikov
melifaro at FreeBSD.org
Thu Jan 16 11:50:01 UTC 2014
Author: melifaro
Date: Thu Jan 16 11:50:00 2014
New Revision: 260702
URL: http://svnweb.freebsd.org/changeset/base/260702
Log:
Fix ipfw fwd for IPv4 traffic broken by r249894.
Problem case:
Original lookup returns route with GW set, so gw points to
rte->rt_gateway.
After that we're changing dst and performing lookup another time.
Since fwd host is most probably directly reachable, resulting
rte does not contain rt_gateway, so gw is not set. Finally, we
end with packet transmitted to proper interface but wrong
link-layer address.
Found by: lstewart
Discussed with: ae,lstewart
MFC after: 2 weeks
Sponsored by: Yandex LLC
Modified:
head/sys/netinet/ip_output.c
Modified: head/sys/netinet/ip_output.c
==============================================================================
--- head/sys/netinet/ip_output.c Thu Jan 16 06:26:03 2014 (r260701)
+++ head/sys/netinet/ip_output.c Thu Jan 16 11:50:00 2014 (r260702)
@@ -202,6 +202,13 @@ ip_output(struct mbuf *m, struct mbuf *o
hlen = ip->ip_hl << 2;
}
+ /*
+ * dst/gw handling:
+ *
+ * dst can be rewritten but always point to &ro->ro_dst
+ * gw is readonly but can be pointed either to dst OR rt_gatewy
+ * therefore we need restore GW if we're re-doing lookup
+ */
gw = dst = (struct sockaddr_in *)&ro->ro_dst;
again:
ia = NULL;
@@ -221,6 +228,7 @@ again:
RO_RTFREE(ro);
ro->ro_lle = NULL;
rte = NULL;
+ gw = dst;
}
if (rte == NULL && fwd_tag == NULL) {
bzero(dst, sizeof(*dst));
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