From 32e668ae2aa11524bedd2705f4be56244eb1bfdd Mon Sep 17 00:00:00 2001
From: Billy Kozak <bkozak@scanimetrics.com>
Date: Tue, 14 Jul 2015 07:53:10 -0600
Subject: [PATCH 1/2] Fix for #1165

It is possible that packetbuf is modified by the call to
mac_call_sent_callback. If this occurs ContikiMAC will not be able to
recognize that a packet is pending.

This fixes this problem by storing pending status in a local variable before
calling mac_call_sent_callback.
---
 core/net/mac/contikimac/contikimac.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/core/net/mac/contikimac/contikimac.c b/core/net/mac/contikimac/contikimac.c
index 74da6ef40..9451de2e0 100644
--- a/core/net/mac/contikimac/contikimac.c
+++ b/core/net/mac/contikimac/contikimac.c
@@ -805,6 +805,7 @@ qsend_list(mac_callback_t sent, void *ptr, struct rdc_buf_list *buf_list)
   struct rdc_buf_list *next;
   int ret;
   int is_receiver_awake;
+  int pending;
   
   if(buf_list == NULL) {
     return;
@@ -849,7 +850,9 @@ qsend_list(mac_callback_t sent, void *ptr, struct rdc_buf_list *buf_list)
 
     /* Prepare the packetbuf */
     queuebuf_to_packetbuf(curr->buf);
-    
+
+    pending = packetbuf_attr(PACKETBUF_ATTR_PENDING);
+
     /* Send the current packet */
     ret = send_packet(sent, ptr, curr, is_receiver_awake);
     if(ret != MAC_TX_DEFERRED) {
@@ -866,7 +869,7 @@ qsend_list(mac_callback_t sent, void *ptr, struct rdc_buf_list *buf_list)
       /* The transmission failed, we stop the burst */
       next = NULL;
     }
-  } while((next != NULL) && packetbuf_attr(PACKETBUF_ATTR_PENDING));
+  } while((next != NULL) && pending);
 }
 /*---------------------------------------------------------------------------*/
 /* Timer callback triggered when receiving a burst, after having

From 467f28286ce082a232da4e6b275b63ffda4537c4 Mon Sep 17 00:00:00 2001
From: Billy Kozak <bkozak@scanimetrics.com>
Date: Tue, 14 Jul 2015 11:04:36 -0600
Subject: [PATCH 2/2] The CSMA driver no longer throttles queued packets

Fix for #1166

Updated the CSMA driver so it no longer applies a time delay for
sending queued packets which were sent without error.
---
 core/net/mac/csma.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/core/net/mac/csma.c b/core/net/mac/csma.c
index ab6fec726..4de46be19 100644
--- a/core/net/mac/csma.c
+++ b/core/net/mac/csma.c
@@ -171,8 +171,10 @@ transmit_packet_list(void *ptr)
 }
 /*---------------------------------------------------------------------------*/
 static void
-free_packet(struct neighbor_queue *n, struct rdc_buf_list *p)
+free_packet(struct neighbor_queue *n, struct rdc_buf_list *p, int status)
 {
+  clock_time_t tx_delay;
+
   if(p != NULL) {
     /* Remove packet from list and deallocate */
     list_remove(n->queued_packet_list, p);
@@ -188,8 +190,8 @@ free_packet(struct neighbor_queue *n, struct rdc_buf_list *p)
       n->collisions = 0;
       n->deferrals = 0;
       /* Set a timer for next transmissions */
-      ctimer_set(&n->transmit_timer, default_timebase(),
-                 transmit_packet_list, n);
+      tx_delay = (status == MAC_TX_OK) ? 0 : default_timebase();
+      ctimer_set(&n->transmit_timer, tx_delay, transmit_packet_list, n);
     } else {
       /* This was the last packet in the queue, we free the neighbor */
       ctimer_stop(&n->transmit_timer);
@@ -293,7 +295,7 @@ packet_sent(void *ptr, int status, int num_transmissions)
         } else {
           PRINTF("csma: drop with status %d after %d transmissions, %d collisions\n",
                  status, n->transmissions, n->collisions);
-          free_packet(n, q);
+          free_packet(n, q, status);
           mac_call_sent_callback(sent, cptr, status, num_tx);
         }
       } else {
@@ -302,7 +304,7 @@ packet_sent(void *ptr, int status, int num_transmissions)
         } else {
           PRINTF("csma: rexmit failed %d: %d\n", n->transmissions, status);
         }
-        free_packet(n, q);
+        free_packet(n, q, status);
         mac_call_sent_callback(sent, cptr, status, num_tx);
       }
     } else {