socket_util: unpack V4MAPPED addresses

src/socket_util.c

@@ -29,9 +29,29 @@
 char *
 sockaddr_to_string(const struct sockaddr *sa, size_t length, GError **error)
 {
+#ifdef HAVE_IPV6
+	const struct sockaddr_in6 *a6 = (const struct sockaddr_in6 *)sa;
+	struct sockaddr_in a4;
+#endif
 	int ret;
 	char host[NI_MAXHOST], serv[NI_MAXSERV];
 
+#ifdef HAVE_IPV6
+	if (sa->sa_family == AF_INET6 &&
+	    IN6_IS_ADDR_V4MAPPED(&a6->sin6_addr)) {
+		/* convert "::ffff:127.0.0.1" to "127.0.0.1" */
+
+		memset(&a4, 0, sizeof(a4));
+		a4.sin_family = AF_INET;
+		memcpy(&a4.sin_addr, ((const char *)&a6->sin6_addr) + 12,
+		       sizeof(a4.sin_addr));
+		a4.sin_port = a6->sin6_port;
+
+		sa = (const struct sockaddr *)&a4;
+		length = sizeof(a4);
+	}
+#endif
+
 	ret = getnameinfo(sa, length, host, sizeof(host), serv, sizeof(serv),
 			  NI_NUMERICHOST|NI_NUMERICSERV);
 	if (ret != 0) {