sys: transceiver: Provide an adapter to basic_net module

Since basic_net is aimed to replace tranceiver one day, but porting
efforts usally take a while, this commit aims to provide access via
transceiver as we are used to for radio/network drivers that already implement
basic_net (e. g. uart_net in RIOT-OS#1454).

sys/include/basic_net.h

@@ -248,6 +248,22 @@ typedef struct {
 } basic_net_reg_t;
 
 
+#ifdef MODULE_TRANSCEIVER
+/**
+ * @brief PID for a basic_net layer, when used with the transceiver module.
+ *
+ * @detail  This variable is only needed, iff this definitions are used with
+ *          the transceiver module in legacy applications. Needs to be set
+ *          externaly (e. g. the layer, that uses basic_net). Guard it against
+ *          other layers using basic_net with the transceiver with
+ *          the macro `HAS_BASIC_NET_PID`, the transceiver module will check
+ *          if it is there and only than allow adapter capabilities. Since
+ *          only one basic_net layer can be used with this hack, it is
+ *          advised to let only layers below network layer use this.
+ */
+extern unsigned int basic_net_pid;
+#endif  /* MODULE_TRANSCEIVER */
+
 #ifdef MODULE_BASIC_NET /* Only include if module basic_net is compiled */
 /**
  * @brief Sends a command to a protocol's control thread.

sys/include/transceiver.h

@@ -132,6 +132,7 @@
 #define TRANSCEIVER_MC1322X     (0x08)      ///< MC1322X transceivers
 #define TRANSCEIVER_NATIVE      (0x10)      ///< NATIVE transceivers
 #define TRANSCEIVER_AT86RF231   (0x20)      ///< AT86RF231 transceivers
+#define TRANSCEIVER_BASIC_NET   (0x30)      ///< basic_net compatible L* layers
 
 /**
  * @brief Data type for transceiver specification
@@ -145,6 +146,10 @@ typedef uint64_t transceiver_eui64_t;
 
 /**
  * @brief Message types for transceiver interface
+ *
+ * @note    **ATTENTION:** Packages received from a basic_net layer are neither
+ *          of type radio_packet_t nor ieee802154_packet_t as they normally are
+ *          (depending on the radio), but basic_net_rcv_pkt_t!
  */
 enum transceiver_msg_type_t {
     /* Message types for driver <-> transceiver communication */