svn commit: r238769 - head/sys/netinet

[Bjoern A. Zeeb]

Author: bz
Date: Wed Jul 25 12:14:39 2012
New Revision: 238769
URL: http://svn.freebsd.org/changeset/base/238769

Log:
  Fix a problem when CARP is enabled on the interface for IPv4
  but not for IPv6.  The current checks in nd6_nbr.c along with the
  old version will result in ifa being NULL and subsequently the
  packet will be dropped.  This prevented NS/NA, from working and
  with that IPv6.
  
  Now return the ifa from the carp lookup function in two cases:
  1) if the address matches, is a carp address, and we are MASTER
     (as before),
  2) if the address matches but it is not a carp address at all (new).
  
  Reported by:	Peter Wemm (new Y! FreeBSD cluster, eating our own dogfood)
  Tested on:	New Y! FreeBSD cluster machines
  Reviewed by:	glebius

Modified:
  head/sys/netinet/ip_carp.c

Modified: head/sys/netinet/ip_carp.c
==============================================================================
--- head/sys/netinet/ip_carp.c	Wed Jul 25 12:06:52 2012	(r238768)
+++ head/sys/netinet/ip_carp.c	Wed Jul 25 12:14:39 2012	(r238769)
@@ -1027,23 +1027,31 @@ carp_send_na(struct carp_softc *sc)
 	}
 }
 
+/*
+ * Returns ifa in case it's a carp address and it is MASTER, or if the address
+ * matches and is not a carp address.  Returns NULL otherwise.
+ */
 struct ifaddr *
 carp_iamatch6(struct ifnet *ifp, struct in6_addr *taddr)
 {
 	struct ifaddr *ifa;
 
+	ifa = NULL;
 	IF_ADDR_RLOCK(ifp);
-	IFNET_FOREACH_IFA(ifp, ifa)
-		if (ifa->ifa_addr->sa_family == AF_INET6 &&
-		    ifa->ifa_carp->sc_state == MASTER &&
-		    IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa))) {
+	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
+		if (ifa->ifa_addr->sa_family != AF_INET6)
+			continue;
+		if (!IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa)))
+			continue;
+		if (ifa->ifa_carp && ifa->ifa_carp->sc_state != MASTER)
+			ifa = NULL;
+		else
 			ifa_ref(ifa);
-			IF_ADDR_RUNLOCK(ifp);
-			return (ifa);
-		}
+		break;
+	}
 	IF_ADDR_RUNLOCK(ifp);
 
-	return (NULL);
+	return (ifa);
 }
 
 caddr_t