A work-in-progress rework of the Contiki MAC and radio layers. The

main ideas are:

* Separates the Contiki low-layer network stack into four layers:
  network (e.g. sicslowpan / rime), Medium Access Control MAC
  (e.g. CSMA), Radio Duty Cycling RDC (e.g. ContikiMAC, X-MAC), and
  radio (e.g. cc2420).
* Introduces a new way to configure the network stack. Four #defines
  that specify what mechanism/protocol/driver to use at the four
  layers: NETSTACK_CONF_NETWORK, NETSTACK_CONF_MAC, NETSTACK_CONF_RDC,
  NETSTACK_CONF_RADIO.
* Adds a callback mechanism to inform the MAC and network layers about
  the fate of a transmitted packet: if the packet was not possible to
  transmit, the cause of the failure is reported, and if the packets
  was successfully transmitted, the number of tries before it was
  finally transmitted is reported.
* NULL-protocols at both the MAC and RDC layers: nullmac and nullrdc,
  which can be used when MAC and RDC functionality is not needed.
* Extends the radio API with three new functions that enable more
  efficient radio duty cycling protocols: channel check, pending
  packet, and receiving packet.
* New initialization mechanism, which takes advantage of the NETSTACK
  #defines.

core/net/mac/mac.h

@@ -28,7 +28,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: mac.h,v 1.11 2010/02/03 16:45:12 adamdunkels Exp $
+ * $Id: mac.h,v 1.12 2010/02/18 21:48:39 adamdunkels Exp $
  */
 
 /**
@@ -44,6 +44,11 @@
 #include "contiki-conf.h"
 #include "dev/radio.h"
 
+
+typedef void (* mac_callback_t)(void *ptr, int status, int transmissions);
+
+void mac_call_sent_callback(mac_callback_t sent, void *ptr, int status, int num_tx);
+
 /**
  * The structure of a MAC protocol driver in Contiki.
  */
@@ -51,17 +56,14 @@ struct mac_driver {
   char *name;
 
   /** Initialize the MAC driver */
-  const struct mac_driver *(* init)(const struct radio_driver *r);
+  void (* init)(void);
 
   /** Send a packet from the Rime buffer  */
-  int (* send)(void);
-
-  /** Read a received packet into the Rime buffer. */
-  int (* read)(void);
-
-  /** Set a function to be called when a packet has been received. */
-  void (* set_receive_function)(void (*f)(const struct mac_driver *d));
+  void (* send)(mac_callback_t sent_callback, void *ptr);
 
+  /** Callback for getting notified of incoming packet. */
+  void (* input)(void);
+  
   /** Turn the MAC layer on. */
   int (* on)(void);