From d68af249eca7ce293916867f4fd2cbd02bad6c19 Mon Sep 17 00:00:00 2001
From: adamdunkels <adamdunkels>
Date: Wed, 3 Feb 2010 01:17:32 +0000
Subject: [PATCH] Added a MAC layer return value that informs the caller that a
 packet did not receive a MAC layer acknowledgement

---
 core/net/mac/cxmac.c | 8 ++++++--
 core/net/mac/mac.h   | 5 ++++-
 core/net/mac/xmac.c  | 8 ++++++--
 3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/core/net/mac/cxmac.c b/core/net/mac/cxmac.c
index 281614ddd..cf098dab6 100644
--- a/core/net/mac/cxmac.c
+++ b/core/net/mac/cxmac.c
@@ -28,7 +28,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: cxmac.c,v 1.7 2010/02/02 23:28:58 adamdunkels Exp $
+ * $Id: cxmac.c,v 1.8 2010/02/03 01:17:32 adamdunkels Exp $
  */
 
 /**
@@ -738,7 +738,11 @@ send_packet(void)
 
   LEDS_OFF(LEDS_BLUE);
   if(collisions == 0) {
-    return MAC_TX_OK;
+    if(!is_broadcast && !got_strobe_ack) {
+      return MAC_TX_NOACK;
+    } else {
+      return MAC_TX_OK;
+    }
   } else {
     someone_is_sending++;
     return MAC_TX_COLLISION;
diff --git a/core/net/mac/mac.h b/core/net/mac/mac.h
index 43527bd4f..d0d8409b3 100644
--- a/core/net/mac/mac.h
+++ b/core/net/mac/mac.h
@@ -28,7 +28,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: mac.h,v 1.9 2010/02/02 23:28:58 adamdunkels Exp $
+ * $Id: mac.h,v 1.10 2010/02/03 01:17:32 adamdunkels Exp $
  */
 
 /**
@@ -80,6 +80,9 @@ enum {
      collision. */
   MAC_TX_COLLISION,
 
+  /**< The MAC layer did not get an acknowledgement for the packet. */
+  MAC_TX_NOACK,
+
   /**< The MAC layer transmission could not be performed because of an
      error. The upper layer may try again later. */
   MAC_TX_ERR,
diff --git a/core/net/mac/xmac.c b/core/net/mac/xmac.c
index eb9374a62..a6b2eb4a1 100644
--- a/core/net/mac/xmac.c
+++ b/core/net/mac/xmac.c
@@ -28,7 +28,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: xmac.c,v 1.51 2010/02/02 23:28:58 adamdunkels Exp $
+ * $Id: xmac.c,v 1.52 2010/02/03 01:17:32 adamdunkels Exp $
  */
 
 /**
@@ -676,7 +676,11 @@ send_packet(void)
 
   LEDS_OFF(LEDS_BLUE);
   if(collisions == 0) {
-    return MAC_TX_OK;
+    if(!is_broadcast && !got_strobe_ack) {
+      return MAC_TX_NOACK;
+    } else {
+      return MAC_TX_OK;
+    }
   } else {
     someone_is_sending++;
     return MAC_TX_COLLISION;