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More verbose description of the source ip address selection for ICMP replies.

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Reviewed by:	bms
This commit is contained in:
Andre Oppermann 2004-02-02 22:17:09 +00:00
parent 9c9c52a3ed
commit 1488eac8ec
1 changed files with 16 additions and 5 deletions
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21
sys/netinet/ip_icmp.c
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@ -632,15 +632,21 @@ icmp_reflect(m)
}
t = ip->ip_dst;
ip->ip_dst = ip->ip_src;
/*
* If the incoming packet was addressed directly to us,
* use dst as the src for the reply. Otherwise (broadcast
* or anonymous), use the address which corresponds
* to the incoming interface.
* Source selection for ICMP replies:
*
* If the incoming packet was addressed directly to one of our
* own addresses, use dst as the src for the reply.
*/
LIST_FOREACH(ia, INADDR_HASH(t.s_addr), ia_hash)
if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr)
goto match;
/*
* If the incoming packet was addressed to one of our broadcast
* addresses, use the first non-broadcast address which corresponds
* to the incoming interface.
*/
if (m->m_pkthdr.rcvif != NULL &&
m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) {
TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) {
@ -652,8 +658,13 @@ icmp_reflect(m)
goto match;
}
}
/*
* If the packet was transiting through us, use the address of
* the interface that is the closest to the packet source.
* When we don't have a route back to the packet source, stop here
* and drop the packet.
*/
ia = ip_rtaddr(ip->ip_dst);
/* We need a route to do anything useful. */
if (ia == NULL) {
m_freem(m);
icmpstat.icps_noroute++;