use getnameinfo instead of gethostbyaddr

Author: remicollet

ext/standard/dns.c

@@ -169,34 +169,44 @@ PHP_FUNCTION(gethostbyaddr)
 static zend_string *php_gethostbyaddr(char *ip)
 {
 #if HAVE_IPV6 && HAVE_INET_PTON
-	struct in6_addr addr6;
-#endif
-	struct in_addr addr;
-	struct hostent *hp;
+	struct sockaddr_in sa4;
+	struct sockaddr_in6 sa6;
+	char out[NI_MAXHOST];
 
-#if HAVE_IPV6 && HAVE_INET_PTON
-	if (inet_pton(AF_INET6, ip, &addr6)) {
-		hp = gethostbyaddr((char *) &addr6, sizeof(addr6), AF_INET6);
-	} else if (inet_pton(AF_INET, ip, &addr)) {
-		hp = gethostbyaddr((char *) &addr, sizeof(addr), AF_INET);
-	} else {
-		return NULL;
+	if (inet_pton(AF_INET6, ip, &sa6.sin6_addr)) {
+		sa6.sin6_family = AF_INET6;
+
+		if (getnameinfo((struct sockaddr *)&sa6, sizeof(sa6), out, sizeof(out), NULL, 0, NI_NAMEREQD) < 0) {
+			return zend_string_init(ip, strlen(ip), 0);
+		}
+		return zend_string_init(out, strlen(out), 0);
+	} else if (inet_pton(AF_INET, ip, &sa4.sin_addr)) {
+		sa4.sin_family = AF_INET;
+
+		if (getnameinfo((struct sockaddr *)&sa4, sizeof(sa4), out, sizeof(out), NULL, 0, NI_NAMEREQD) < 0) {
+			return zend_string_init(ip, strlen(ip), 0);
+		}
+		return zend_string_init(out, strlen(out), 0);
 	}
+	return NULL; /* not a valid IP */
 #else
+	struct in_addr addr;
+	struct hostent *hp;
+
 	addr.s_addr = inet_addr(ip);
 
 	if (addr.s_addr == -1) {
 		return NULL;
 	}
 
 	hp = gethostbyaddr((char *) &addr, sizeof(addr), AF_INET);
-#endif
 
 	if (!hp || hp->h_name == NULL || hp->h_name[0] == '\0') {
 		return zend_string_init(ip, strlen(ip), 0);
 	}
 
 	return zend_string_init(hp->h_name, strlen(hp->h_name), 0);
+#endif
 }
 /* }}} */