--- /home/bms/fp4/nethead/sys/netinet/ip_encap.c	Thu Sep 28 18:21:51 2006
+++ /home/bms/fp4/nethead/sys/netinet/ip_encap.c	Thu Sep 28 18:21:09 2006
@@ -403,6 +403,7 @@ 
 	const struct sockaddr *sp;
 	const struct sockaddr *dp;
 {
+	const int hdrlen = offsetof(struct sockaddr, sa_data);
 	struct sockaddr_storage s;
 	struct sockaddr_storage d;
 	int i;
@@ -419,32 +420,28 @@ 
 
 	matchlen = 0;
 
-	p = (const u_int8_t *)sp;
-	q = (const u_int8_t *)&ep->srcmask;
-	r = (u_int8_t *)&s;
-	for (i = 0 ; i < sp->sa_len; i++) {
+	p = (const u_int8_t *)&sp->sa_data;
+	q = (const u_int8_t *)&ep->srcmask + hdrlen;
+	r = (u_int8_t *)&s + hdrlen;
+	for (i = 0 ; i < sp->sa_len - hdrlen; i++) {
 		r[i] = p[i] & q[i];
 		/* XXX estimate */
 		matchlen += (q[i] ? 8 : 0);
 	}
 
-	p = (const u_int8_t *)dp;
-	q = (const u_int8_t *)&ep->dstmask;
-	r = (u_int8_t *)&d;
-	for (i = 0 ; i < dp->sa_len; i++) {
+	p = (const u_int8_t *)&dp->sa_data;
+	q = (const u_int8_t *)&ep->dstmask + hdrlen;
+	r = (u_int8_t *)&d + hdrlen;
+	for (i = 0 ; i < dp->sa_len - hdrlen; i++) {
 		r[i] = p[i] & q[i];
 		/* XXX rough estimate */
 		matchlen += (q[i] ? 8 : 0);
 	}
 
-	/* need to overwrite len/family portion as we don't compare them */
-	s.ss_len = sp->sa_len;
-	s.ss_family = sp->sa_family;
-	d.ss_len = dp->sa_len;
-	d.ss_family = dp->sa_family;
-
-	if (bcmp(&s, &ep->src, ep->src.ss_len) == 0 &&
-	    bcmp(&d, &ep->dst, ep->dst.ss_len) == 0) {
+	if (bcmp((u_int8_t *)&s + hdrlen, (const u_int8_t *)&ep->src + hdrlen,
+	    ep->src.ss_len - hdrlen) == 0 &&
+	    bcmp((u_int8_t *)&d + hdrlen, (const u_int8_t *)&ep->dst + hdrlen,
+	    ep->dst.ss_len - hdrlen) == 0) {
 		return matchlen;
 	} else
 		return 0;