libceph: treat sockaddr_storage with uninitialized family as blank

addr_is_blank() should return true if family is neither AF_INET nor
AF_INET6.  This is what its counterpart entity_addr_t::is_blank_ip() is
doing and it is the right thing to do: in process_banner() we check if
our address is blank and if it is "learn" it from our peer.  As it is,
we never learn our address and always send out a blank one.  This goes
way back to ceph.git commit dd732cbfc1c9 ("use sockaddr_storage; and
some ipv6 support groundwork") from 2009.

While at at, do not open-code ipv6_addr_any() and use INADDR_ANY
constant instead of 0.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Sage Weil <sage@redhat.com>

net/ceph/messenger.c

@@ -1732,17 +1732,17 @@ static int verify_hello(struct ceph_connection *con)
 
 static bool addr_is_blank(struct sockaddr_storage *ss)
 {
+	struct in_addr *addr = &((struct sockaddr_in *)ss)->sin_addr;
+	struct in6_addr *addr6 = &((struct sockaddr_in6 *)ss)->sin6_addr;
+
 	switch (ss->ss_family) {
 	case AF_INET:
-		return ((struct sockaddr_in *)ss)->sin_addr.s_addr == 0;
+		return addr->s_addr == htonl(INADDR_ANY);
 	case AF_INET6:
-		return
-		     ((struct sockaddr_in6 *)ss)->sin6_addr.s6_addr32[0] == 0 &&
-		     ((struct sockaddr_in6 *)ss)->sin6_addr.s6_addr32[1] == 0 &&
-		     ((struct sockaddr_in6 *)ss)->sin6_addr.s6_addr32[2] == 0 &&
-		     ((struct sockaddr_in6 *)ss)->sin6_addr.s6_addr32[3] == 0;
+		return ipv6_addr_any(addr6);
+	default:
+		return true;
 	}
-	return false;
 }
 
 static int addr_port(struct sockaddr_storage *ss)