A system may have multiple physical interfaces, all of which are on the

same prefix. Since a single route entry is installed for the prefix
(without RADIX_MPATH), incoming packets on the interfaces that are not
associated with the prefix route may trigger an error message about
unable to allocation LLE entry, and fails L2. This patch makes sure a
valid route is present in the system, and allow the aforementioned
condition to exist and treats as valid.

Reviewed by:	bz
MFC after:	5 days

1 files changed, 34 insertions, 5 deletions

diff --git a/sys/netinet/in.c b/sys/netinet/in.c
index c2e43cc..da4e8a0 100644
--- a/sys/netinet/in.c
+++ b/sys/netinet/in.c
@@ -1439,14 +1439,43 @@ in_lltable_rtcheck(struct ifnet *ifp, u_int flags, const struct sockaddr *l3addr
 		if (memcmp(rt->rt_gateway->sa_data, l3addr->sa_data,
 		    sizeof(in_addr_t)) != 0)
 			error = EINVAL;
-	} else if (!(flags & LLE_PUB) && ((rt->rt_flags & RTF_GATEWAY) ||
-	    (rt->rt_ifp != ifp))) {
+	}
+
+	if (rt->rt_flags & RTF_GATEWAY) {
+		RTFREE_LOCKED(rt);
+		return (EINVAL);
+	}
+
+	/*
+	 * Make sure that at least the destination address is covered 
+	 * by the route. This is for handling the case where 2 or more 
+	 * interfaces have the same prefix. An incoming packet arrives
+	 * on one interface and the corresponding outgoing packet leaves
+	 * another interface.
+	 * 
+	 */
+	if (rt->rt_ifp != ifp) {
+		char *sa, *mask, *addr, *lim;
+		int len;
+
+		sa = (char *)rt_key(rt);
+		mask = (char *)rt_mask(rt);
+		addr = (char *)__DECONST(struct sockaddr *, l3addr);
+		len = ((struct sockaddr_in *)__DECONST(struct sockaddr *, l3addr))->sin_len;
+		lim = addr + len;
+
+		for ( ; addr < lim; sa++, mask++, addr++) {
+			if ((*sa ^ *addr) & *mask) {
+				error = EINVAL;
 #ifdef DIAGNOSTIC
-		log(LOG_INFO, "IPv4 address: \"%s\" is not on the network\n",
-		    inet_ntoa(((const struct sockaddr_in *)l3addr)->sin_addr));
+				log(LOG_INFO, "IPv4 address: \"%s\" is not on the network\n",
+				    inet_ntoa(((const struct sockaddr_in *)l3addr)->sin_addr));
 #endif
-		error = EINVAL;
+				break;
+			}
+		}
 	}
+
 	RTFREE_LOCKED(rt);
 	return (error);
 }