Update to FreeBSD head 2016-12-10

Git mirror commit 80c55f08a05ab3b26a73b226ccb56adc3122a55c.

freebsd/lib/libc/net/getaddrinfo.c

@@ -226,6 +226,7 @@ struct ai_order {
 	struct policyqueue *aio_dstpolicy;
 	struct addrinfo *aio_ai;
 	int aio_matchlen;
+	int aio_initial_sequence;
 };
 
 static const ns_src default_dns_files[] = {
@@ -710,6 +711,7 @@ reorder(struct addrinfo *sentinel)
 		aio[i].aio_dstpolicy = match_addrselectpolicy(ai->ai_addr,
 							      &policyhead);
 		set_source(&aio[i], &policyhead);
+		aio[i].aio_initial_sequence = i;
 	}
 
 	/* perform sorting. */
@@ -949,7 +951,7 @@ matchlen(struct sockaddr *src, struct sockaddr *dst)
 
 	while (s < lim)
 		if ((r = (*d++ ^ *s++)) != 0) {
-			while (r < addrlen * 8) {
+			while ((r & 0x80) == 0) {
 				match++;
 				r <<= 1;
 			}
@@ -1068,6 +1070,23 @@ comp_dst(const void *arg1, const void *arg2)
 	}
 
 	/* Rule 10: Otherwise, leave the order unchanged. */
+
+	/* 
+	 * Note that qsort is unstable; so, we can't return zero and 
+	 * expect the order to be unchanged.
+	 * That also means we can't depend on the current position of
+	 * dst2 being after dst1.  We must enforce the initial order
+	 * with an explicit compare on the original position.
+	 * The qsort specification requires that "When the same objects 
+	 * (consisting of width bytes, irrespective of their current 
+	 * positions in the array) are passed more than once to the 
+	 * comparison function, the results shall be consistent with one 
+	 * another."  
+	 * In other words, If A < B, then we must also return B > A.
+	 */
+	if (dst2->aio_initial_sequence < dst1->aio_initial_sequence)
+		return(1);
+
 	return(-1);
 }