RFC: Fix aliasing warning (gcc)

This patch is kind of ugly, but it should be backwards compat,
and it fixes aliasing warnings that I see on Fedora 13 and allows
a clean build, even with --enable-errors and --enable-werror

Please yell if you don't want this or otherwise want it improved,
otherwise will commit it tomorrow and check all the auto-builds :)

Thanks,
Ben

[greearb_at_grok2 c-ares]$ git diff
diff --git a/ares_process.c b/ares_process.c
index c3d7fa4..320dd5e 100644
--- a/ares_process.c
+++ b/ares_process.c
@@ -434,11 +434,15 @@ 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))
      /* no possible action */
@@ -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.sa4);
- else
- fromlen = sizeof(from.sa6);
+ fromlen = sizeof(from); /* doesn't matter if it's larger than needed */
          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 */
  }

-- 
Ben Greear <greearb_at_candelatech.com>
Candela Technologies Inc  http://www.candelatech.com