Warning fix

src/sn_utils.c

@@ -1309,7 +1309,7 @@ static int process_udp(n2n_sn_t * sss,
     }
 
     tmp_sock = (n2n_sock_t *)dec_tmpbuf;
-    tmp_mac = (n2n_sock_t *)dec_tmpbuf + sizeof(n2n_sock_t);
+    tmp_mac  = (n2n_mac_t *)(dec_tmpbuf + sizeof(n2n_sock_t));
 
     for(i=0; i<ack.num_sn; i++) {
       skip_add = SN_ADD;
@@ -1321,7 +1321,7 @@ static int process_udp(n2n_sn_t * sss,
 
       /* REVISIT: find a more elegant expression to increase following pointers. */
       tmp_sock = tmp_sock + REG_SUPER_ACK_PAYLOAD_ENTRY_SIZE;
-      tmp_mac = tmp_sock + sizeof(n2n_sock_t);
+      tmp_mac  = (n2n_mac_t *)(tmp_sock + sizeof(n2n_sock_t));
     }
 
     break;