From f25856a38742bcdf6f432f73395869e44e1b0e9c Mon Sep 17 00:00:00 2001
From: adamdunkels <adamdunkels>
Date: Sun, 18 Oct 2009 22:03:44 +0000
Subject: [PATCH] Hack to be able to receive UDPv4 multicast packets

---
 core/net/uip.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/core/net/uip.c b/core/net/uip.c
index fda6f98b5..74d470b33 100644
--- a/core/net/uip.c
+++ b/core/net/uip.c
@@ -41,7 +41,7 @@
  *
  * This file is part of the uIP TCP/IP stack.
  *
- * $Id: uip.c,v 1.15 2008/10/15 08:08:32 adamdunkels Exp $
+ * $Id: uip.c,v 1.16 2009/10/18 22:03:44 adamdunkels Exp $
  *
  */
 
@@ -903,9 +903,16 @@ uip_process(u8_t flag)
 #if UIP_BROADCAST
     DEBUG_PRINTF("UDP IP checksum 0x%04x\n", uip_ipchksum());
     if(BUF->proto == UIP_PROTO_UDP &&
-       uip_ipaddr_cmp(&BUF->destipaddr, &uip_broadcast_addr)
-       /*&&
-	 uip_ipchksum() == 0xffff*/) {
+       (uip_ipaddr_cmp(&BUF->destipaddr, &uip_broadcast_addr) ||
+	(BUF->destipaddr.u8[0] & 224) == 224)) {  /* XXX this is a
+						     hack to be able
+						     to receive UDP
+						     multicast
+						     packets. We check
+						     for the bit
+						     pattern of the
+						     multicast
+						     prefix. */
       goto udp_input;
     }
 #endif /* UIP_BROADCAST */
@@ -1814,7 +1821,7 @@ uip_process(u8_t flag)
      to set the appropriate TCP sequence numbers in the TCP header. */
  tcp_send_ack:
   BUF->flags = TCP_ACK;
-
+  
  tcp_send_nodata:
   uip_len = UIP_IPTCPH_LEN;
 
@@ -1852,7 +1859,7 @@ uip_process(u8_t flag)
     BUF->wnd[0] = ((UIP_RECEIVE_WINDOW) >> 8);
     BUF->wnd[1] = ((UIP_RECEIVE_WINDOW) & 0xff);
   }
-
+  
  tcp_send_noconn:
   BUF->ttl = UIP_TTL;
 #if UIP_CONF_IPV6