Fix aliasing warning in gcc 4.4.4 (at least).

Should be no functional change, though the code gets a bit
ugglier.

Signed-off-by: Ben Greear <greearb@candelatech.com>

ares_process.c

@@ -434,10 +434,14 @@ static void read_udp_packets(ares_channel channel, fd_set *read_fds,
   unsigned char buf[PACKETSZ + 1];
 #ifdef HAVE_RECVFROM
   ares_socklen_t fromlen;
+#ifdef HAVE_STRUCT_SOCKADDR_STORAGE
+  struct sockaddr_storage from;
+#else
   union {
     struct sockaddr_in  sa4;
     struct sockaddr_in6 sa6;
   } from;
+#endif
 #endif
 
   if(!read_fds && (read_fd == ARES_SOCKET_BAD))
@@ -473,10 +477,7 @@ static void read_udp_packets(ares_channel channel, fd_set *read_fds,
        * packets as we can. */
       do {
 #ifdef HAVE_RECVFROM
-        if (server->addr.family == AF_INET)
+        fromlen = sizeof(from); /* doesn't matter if it's larger than needed */
-          fromlen = sizeof(from.sa4);
-        else
-          fromlen = sizeof(from.sa6);
         count = (ssize_t)recvfrom(server->udp_socket, (void *)buf, sizeof(buf),
                                   0, (struct sockaddr *)&from, &fromlen);
 #else
@@ -487,7 +488,15 @@ static void read_udp_packets(ares_channel channel, fd_set *read_fds,
         else if (count <= 0)
           handle_error(channel, i, now);
 #ifdef HAVE_RECVFROM
-        else if (!same_address((struct sockaddr *)&from, &server->addr))
+#ifdef HAVE_STRUCT_SOCKADDR_STORAGE
+        /* This family hack works around compiler warnings about
+         * aliases.
+         */
+        else if (!((from.ss_family == server->addr.family) &&
+                   same_address((struct sockaddr *)&from, &server->addr)))
+#else
+        else if (!same_address((struct sockaddr *)&from, &server->addr)))
+#endif
           /* The address the response comes from does not match
            * the address we sent the request to. Someone may be
            * attempting to perform a cache poisoning attack. */
@@ -1177,8 +1186,10 @@ static int same_address(struct sockaddr *sa, struct ares_addr *aa)
   void *addr1;
   void *addr2;
 
+#ifndef HAVE_STRUCT_SOCKADDR_STORAGE
   if (sa->sa_family == aa->family)
     {
+#endif
       switch (aa->family)
         {
           case AF_INET:
@@ -1196,7 +1207,9 @@ static int same_address(struct sockaddr *sa, struct ares_addr *aa)
           default:
             break;
         }
+#ifndef HAVE_STRUCT_SOCKADDR_STORAGE
     }
+#endif
   return 0; /* different */
 }