Index: include/netdb.h
===================================================================
--- include/netdb.h	(revision 292012)
+++ include/netdb.h	(working copy)
@@ -179,7 +179,7 @@
 /* valid flags for addrinfo (not a standard def, apps should not use it) */
 #define AI_MASK \
     (AI_PASSIVE | AI_CANONNAME | AI_NUMERICHOST | AI_NUMERICSERV | \
-    AI_ADDRCONFIG)
+    AI_ADDRCONFIG | AI_ALL | AI_V4MAPPED)
 
 #define	AI_ALL		0x00000100 /* IPv6 and IPv4-mapped (with AI_V4MAPPED) */
 #define	AI_V4MAPPED_CFG	0x00000200 /* accept IPv4-mapped if kernel supports */
Index: lib/libc/net/getaddrinfo.c
===================================================================
--- lib/libc/net/getaddrinfo.c	(revision 292129)
+++ lib/libc/net/getaddrinfo.c	(working copy)
@@ -470,6 +470,22 @@
 	}
 
 	/*
+	 * RFC 3493: AI_ALL and AI_V4MAPPED are effective only against
+	 * AF_INET6 query.  They need to be ignored if specified in other
+	 * occassions.
+	 */
+	switch (pai->ai_flags & (AI_ALL | AI_V4MAPPED)) {
+	case AI_V4MAPPED:
+	case AI_ALL | AI_V4MAPPED:
+		if (pai->ai_family != AF_INET6)
+			pai->ai_flags &= ~(AI_ALL | AI_V4MAPPED);
+		break;
+	case AI_ALL:
+		pai->ai_flags &= ~(AI_ALL | AI_V4MAPPED);
+		break;
+	}
+
+	/*
 	 * check for special cases.  (1) numeric servname is disallowed if
 	 * socktype/protocol are left unspecified. (2) servname is disallowed
 	 * for raw and other inet{,6} sockets.
@@ -861,6 +877,17 @@
 	if ((s = _socket(ai.ai_family, ai.ai_socktype | SOCK_CLOEXEC,
 	    ai.ai_protocol)) < 0)
 		return;		/* give up */
+	if (ai.ai_family == AF_INET6) {
+		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)ai.ai_addr;
+		int off = 0, ret;
+
+		if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) {
+			ret = _setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY,
+			    (char *)&off, sizeof(off));
+			if (ret < 0)
+				goto cleanup;
+		}
+	}
 	if (_connect(s, ai.ai_addr, ai.ai_addrlen) < 0)
 		goto cleanup;
 	srclen = ai.ai_addrlen;
@@ -1199,7 +1226,7 @@
     const char *servname, struct addrinfo **res, const char *canonname)
 {
 	const struct afd *afd;
-	struct addrinfo *ai;
+	struct addrinfo *ai, ai0;
 	int error;
 	char pton[PTON_MAX], path[PATH_MAX], *p;
 
@@ -1236,8 +1263,17 @@
 		p = pton;
 		break;
 	default:
-		if (inet_pton(afd->a_af, hostname, pton) != 1)
-			return 0;
+		if (inet_pton(afd->a_af, hostname, pton) != 1) {
+			if (pai->ai_family != AF_INET6 ||
+			    (pai->ai_flags & AI_V4MAPPED) != AI_V4MAPPED)
+				return 0;
+			if (inet_aton(hostname, (struct in_addr *)pton) != 1)
+				return 0;
+			afd = &afdl[N_INET];
+			ai0 = *pai;
+			ai0.ai_family = AF_INET;
+			pai = &ai0;
+		}
 		p = pton;
 		break;
 	}
@@ -1354,7 +1390,16 @@
 {
 	char *p;
 	struct addrinfo *ai;
+	struct in6_addr mapaddr;
 
+	if (afd->a_af == AF_INET && (pai->ai_flags & AI_V4MAPPED) != 0) {
+		afd = &afdl[N_INET6];
+		memset(&mapaddr.s6_addr[0], 0, 10);
+		memset(&mapaddr.s6_addr[10], 0xff, 2);
+		memcpy(&mapaddr.s6_addr[12], addr, sizeof(struct in_addr));
+		addr = (char *)&mapaddr;
+	}
+
 	ai = (struct addrinfo *)malloc(sizeof(struct addrinfo)
 		+ (afd->a_socklen));
 	if (ai == NULL)
@@ -2192,7 +2237,7 @@
 static int
 _dns_getaddrinfo(void *rv, void *cb_data, va_list ap)
 {
-	struct addrinfo *ai;
+	struct addrinfo *ai, ai0;
 	querybuf *buf, *buf2;
 	const char *hostname;
 	const struct addrinfo *pai;
@@ -2222,6 +2267,13 @@
 		return NS_NOTFOUND;
 	}
 
+	if (pai->ai_family == AF_INET6 &&
+	    (pai->ai_flags & AI_V4MAPPED) == AI_V4MAPPED) {
+		ai0 = *pai;
+		ai0.ai_family = AF_UNSPEC;
+		pai = &ai0;
+	}
+
 	switch (pai->ai_family) {
 	case AF_UNSPEC:
 		q.name = hostname;
@@ -2277,9 +2329,12 @@
 				cur = cur->ai_next;
 		}
 	}
-	ai = getanswer(buf, q.n, q.name, q.qtype, pai, res);
-	if (ai)
-		cur->ai_next = ai;
+	if (!ai || pai->ai_family != AF_UNSPEC ||
+	    (pai->ai_flags & (AI_ALL | AI_V4MAPPED)) != AI_V4MAPPED) {
+		ai = getanswer(buf, q.n, q.name, q.qtype, pai, res);
+		if (ai)
+			cur->ai_next = ai;
+	}
 	free(buf);
 	free(buf2);
 	if (sentinel.ai_next == NULL)
@@ -2362,6 +2417,17 @@
 	hints.ai_protocol = 0;
 	hints.ai_flags = AI_NUMERICHOST;
 	error = getaddrinfo(addr, "0", &hints, &res0);
+	if (error) {
+		/*
+		 * XXX: Both IPv6 address and IPv4-mapped IPv6 address
+		 * are returned without specifying AI_ALL.
+		 */
+		if (pai->ai_family != AF_INET6 ||
+		    (pai->ai_flags & AI_V4MAPPED) != AI_V4MAPPED)
+			goto again;
+		hints.ai_flags |= AI_V4MAPPED;
+		error = getaddrinfo(addr, "0", &hints, &res0);
+	}
 	if (error)
 		goto again;
 #ifdef FILTER_V4MAPPED
@@ -2470,6 +2536,13 @@
 	hints = *pai;
 	hints.ai_flags = AI_NUMERICHOST;
 	error = getaddrinfo(addr, NULL, &hints, &res0);
+	if (error) {
+		if (pai->ai_family == AF_INET6 &&
+		    (pai->ai_flags & AI_V4MAPPED) == AI_V4MAPPED) {
+			hints.ai_flags |= AI_V4MAPPED;
+			error = getaddrinfo(addr, NULL, &hints, &res0);
+		}
+	}
 	if (error == 0) {
 		for (res = res0; res; res = res->ai_next) {
 			/* cover it up */