Followed Steve's good recommendation, and made routed_get_my_address() be a variant of datalink_get_my_address() just when routing is in use. Haven't done anything about the sending functions yet.

Renamed Lookup_Routed_Device_Address() as Routed_Device_Address_Lookup(), and replaced it in the routed npdu handler with a function that finds the "next" gateway or routed device, as per the destination address.  (Less tied to the specifics of the gw_device.c implementation.)
Fixed a few build warnings (eg, %zu for size_t arguments).
Until we improve the makefile system, I've enabled BAC_ROUTING in config.h

bacnet-stack/demo/handler/h_alarm_ack.c

@@ -69,11 +69,7 @@ void handler_alarm_ack(
     BACNET_ADDRESS my_address;
 
     /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-    my_address = *Get_Routed_Device_Address(-1);
-#else
     datalink_get_my_address(&my_address);
-#endif
     npdu_encode_npdu_data(&npdu_data, false, MESSAGE_PRIORITY_NORMAL);
     pdu_len =
         npdu_encode_pdu(&Handler_Transmit_Buffer[0], src, &my_address,

bacnet-stack/demo/handler/h_arf.c

@@ -118,11 +118,7 @@ void handler_atomic_read_file(
     fprintf(stderr, "Received Atomic-Read-File Request!\n");
 #endif
     /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-    my_address = *Get_Routed_Device_Address(-1);
-#else
     datalink_get_my_address(&my_address);
-#endif
     npdu_encode_npdu_data(&npdu_data, false, MESSAGE_PRIORITY_NORMAL);
     pdu_len =
         npdu_encode_pdu(&Handler_Transmit_Buffer[0], src, &my_address,
@@ -174,7 +170,7 @@ void handler_atomic_read_file(
                     service_data->invoke_id,
                     ABORT_REASON_SEGMENTATION_NOT_SUPPORTED, true);
 #if PRINT_ENABLED
-                fprintf(stderr, "Too Big To Send (%d >= %d). Sending Abort!\n",
+                fprintf(stderr, "Too Big To Send (%d >= %zu). Sending Abort!\n",
                     data.type.stream.requestedOctetCount,
                     octetstring_capacity(&data.fileData));
 #endif

bacnet-stack/demo/handler/h_awf.c

@@ -96,11 +96,7 @@ void handler_atomic_write_file(
     fprintf(stderr, "Received AtomicWriteFile Request!\n");
 #endif
     /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-    my_address = *Get_Routed_Device_Address(-1);
-#else
     datalink_get_my_address(&my_address);
-#endif
     npdu_encode_npdu_data(&npdu_data, false, MESSAGE_PRIORITY_NORMAL);
     pdu_len =
         npdu_encode_pdu(&Handler_Transmit_Buffer[0], src, &my_address,
@@ -132,7 +128,7 @@ void handler_atomic_write_file(
         } else if (data.access == FILE_STREAM_ACCESS) {
             if (bacfile_write_stream_data(&data)) {
 #if PRINT_ENABLED
-                fprintf(stderr, "AWF: Stream offset %d, %d bytes\n",
+                fprintf(stderr, "AWF: Stream offset %d, %zu bytes\n",
                     data.type.stream.fileStartPosition,
                     octetstring_length(&data.fileData));
 #endif

bacnet-stack/demo/handler/h_cov.c

@@ -326,11 +326,7 @@ static bool cov_send_request(
 #if PRINT_ENABLED
     fprintf(stderr, "COVnotification: requested\n");
 #endif
-#if BAC_ROUTING
-    my_address = *Get_Routed_Device_Address(-1);
-#else
     datalink_get_my_address(&my_address);
-#endif
     npdu_encode_npdu_data(&npdu_data, false, MESSAGE_PRIORITY_NORMAL);
     pdu_len =
         npdu_encode_pdu(&Handler_Transmit_Buffer[0], &cov_subscription->dest,
@@ -528,11 +524,7 @@ void handler_cov_subscribe(
     /* initialize a common abort code */
     cov_data.error_code = ABORT_REASON_SEGMENTATION_NOT_SUPPORTED;
     /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-    my_address = *Get_Routed_Device_Address(-1);
-#else
     datalink_get_my_address(&my_address);
-#endif
     npdu_encode_npdu_data(&npdu_data, false, MESSAGE_PRIORITY_NORMAL);
     npdu_len =
         npdu_encode_pdu(&Handler_Transmit_Buffer[0], src, &my_address,

bacnet-stack/demo/handler/h_dcc.c

@@ -103,11 +103,7 @@ void handler_device_communication_control(
     BACNET_ADDRESS my_address;
 
     /* encode the NPDU portion of the reply packet */
-#if BAC_ROUTING
-    my_address = *Get_Routed_Device_Address(-1);
-#else
     datalink_get_my_address(&my_address);
-#endif
     npdu_encode_npdu_data(&npdu_data, false, MESSAGE_PRIORITY_NORMAL);
     pdu_len =
         npdu_encode_pdu(&Handler_Transmit_Buffer[0], src, &my_address,

bacnet-stack/demo/handler/h_getevent.c

@@ -72,11 +72,7 @@ void handler_get_event_information(
     int valid_event = 0;
 
     /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-    my_address = *Get_Routed_Device_Address(-1);
-#else
     datalink_get_my_address(&my_address);
-#endif
     npdu_encode_npdu_data(&npdu_data, false, MESSAGE_PRIORITY_NORMAL);
     pdu_len =
         npdu_encode_pdu(&Handler_Transmit_Buffer[0], src, &my_address,

bacnet-stack/demo/handler/h_lso.c

@@ -54,11 +54,7 @@ void handler_lso(
     BACNET_ADDRESS my_address;
 
     /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-    my_address = *Get_Routed_Device_Address(-1);
-#else
     datalink_get_my_address(&my_address);
-#endif
     npdu_encode_npdu_data(&npdu_data, false, MESSAGE_PRIORITY_NORMAL);
     pdu_len =
         npdu_encode_pdu(&Handler_Transmit_Buffer[0], src, &my_address,

bacnet-stack/demo/handler/h_npdu.c

@@ -46,6 +46,8 @@
  *  and passing the remaining bytes to the apdu_handler.
  *  @note The routing (except src) and NCPI information, including 
  *  npdu_data->data_expecting_reply, are discarded.
+ * @see routing_npdu_handler
+ *  
  * @ingroup MISCHNDLR
  *  
  * @param src  [out] Returned with routing source information if the NPDU 

bacnet-stack/demo/handler/h_pt.c

@@ -231,11 +231,7 @@ void handler_conf_private_trans(
     /* encode the NPDU portion of the response packet as it will be needed */
     /* no matter what the outcome. */
 
-#if BAC_ROUTING
-    my_address = *Get_Routed_Device_Address(-1);
-#else
     datalink_get_my_address(&my_address);
-#endif
     npdu_encode_npdu_data(&npdu_data, false, MESSAGE_PRIORITY_NORMAL);
     pdu_len =
         npdu_encode_pdu(&Handler_Transmit_Buffer[0], src, &my_address,

bacnet-stack/demo/handler/h_rd.c

@@ -77,11 +77,7 @@ void handler_reinitialize_device(
     BACNET_ADDRESS my_address;
 
     /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-    my_address = *Get_Routed_Device_Address(-1);
-#else
     datalink_get_my_address(&my_address);
-#endif
     npdu_encode_npdu_data(&npdu_data, false, MESSAGE_PRIORITY_NORMAL);
     pdu_len =
         npdu_encode_pdu(&Handler_Transmit_Buffer[0], src, &my_address,

bacnet-stack/demo/handler/h_routed_npdu.c

@@ -197,30 +197,16 @@ static void routed_apdu_handler(
     uint8_t * apdu,      
     uint16_t apdu_len)
 {       
-    int dnet = DNET_list[0];	/* Get the DNET of our virtual network */
-    int i;
+    int cursor = 0;				/* Starting hint */
+    bool bGotOne = false;
     
-    /* First, see if it's for the main Gateway Device, either because 
-     * there's no routing info or else its a BACnet broadcast.
-     */
-    if ( (dest->net == 0 ) || (dest->net == BACNET_BROADCAST_NETWORK)) {
-        /* Handle like a normal, non-routed access of the Gateway Device.
-         * But first, make sure our internal access is pointing at
-         * that Device in our table by telling it "no routing info" : */
-        Lookup_Routed_Device_Address( 0, 0, NULL );
-        apdu_handler(src, apdu, apdu_len);
+   	while ( Routed_Device_GetNext( dest, DNET_list, &cursor ) ) {
+			apdu_handler(src, apdu, apdu_len);
+			bGotOne = true;
+			if ( cursor < 0 )	/* If no more matches, */
+				break;			/* We don't need to keep looking */
     }
-    /* Now check for our virtual DNET or BACnet broadcast, and check
-     * against each of our virtually routed Devices.
-     * If we get a match, have it handle the APDU.
-     * For broadcasts, all Devices get a chance at it.
-     */
-    if ((dest->net == dnet) || (dest->net == BACNET_BROADCAST_NETWORK)) {
-    	for ( i = 1; i < MAX_NUM_DEVICES; i++ ) {
-            if ( Lookup_Routed_Device_Address( i, dest->len, dest->adr ) )
-            	apdu_handler(src, apdu, apdu_len);
-    	}
-    } else if ( dest->net != 0 )  {
+    if ( !bGotOne )  {
         /* We don't know how to reach this one */
         Send_Reject_Message_To_Network( src, NETWORK_REJECT_NO_ROUTE, dest->net );
     }
@@ -237,6 +223,7 @@ static void routed_apdu_handler(
  *      destination.
  *  - Errors in decoding.
  * @note The npdu_data->data_expecting_reply status is discarded.
+ * @see npdu_handler
  * @ingroup NMRC
  *  
  * @param src  [out] Returned with routing source information if the NPDU 

bacnet-stack/demo/handler/h_rp.c

@@ -83,11 +83,7 @@ void handler_read_property(
     /* configure default error code as an abort since it is common */
     rpdata.error_code = ERROR_CODE_ABORT_SEGMENTATION_NOT_SUPPORTED;
     /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-    my_address = *Get_Routed_Device_Address(-1);
-#else
     datalink_get_my_address(&my_address);
-#endif
     npdu_encode_npdu_data(&npdu_data, false, MESSAGE_PRIORITY_NORMAL);
     npdu_len =
         npdu_encode_pdu(&Handler_Transmit_Buffer[0], src, &my_address,

bacnet-stack/demo/handler/h_rpm.c

@@ -204,11 +204,7 @@ void handler_read_property_multiple(
     /* jps_debug - see if we are utilizing all the buffer */
     /* memset(&Handler_Transmit_Buffer[0], 0xff, sizeof(Handler_Transmit_Buffer)); */
     /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-    my_address = *Get_Routed_Device_Address(-1);
-#else
     datalink_get_my_address(&my_address);
-#endif
     npdu_encode_npdu_data(&npdu_data, false, MESSAGE_PRIORITY_NORMAL);
     npdu_len =
         npdu_encode_pdu(&Handler_Transmit_Buffer[0], src, &my_address,

bacnet-stack/demo/handler/h_rr.c

@@ -104,11 +104,7 @@ void handler_read_range(
     data.error_class = ERROR_CLASS_OBJECT;
     data.error_code = ERROR_CODE_UNKNOWN_OBJECT;
     /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-    my_address = *Get_Routed_Device_Address(-1);
-#else
     datalink_get_my_address(&my_address);
-#endif
     npdu_encode_npdu_data(&npdu_data, false, MESSAGE_PRIORITY_NORMAL);
     pdu_len =
         npdu_encode_pdu(&Handler_Transmit_Buffer[0], src, &my_address,

bacnet-stack/demo/handler/h_wp.c

@@ -75,11 +75,7 @@ void handler_write_property(
     BACNET_ADDRESS my_address;
 
     /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-    my_address = *Get_Routed_Device_Address(-1);
-#else
     datalink_get_my_address(&my_address);
-#endif
     npdu_encode_npdu_data(&npdu_data, false, MESSAGE_PRIORITY_NORMAL);
     pdu_len =
         npdu_encode_pdu(&Handler_Transmit_Buffer[0], src, &my_address,

bacnet-stack/demo/handler/noserv.c

@@ -65,11 +65,7 @@ void handler_unrecognized_service(
     (void) service_len;
 
     /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-    my_address = *Get_Routed_Device_Address(-1);
-#else
     datalink_get_my_address(&my_address);
-#endif
     npdu_encode_npdu_data(&npdu_data, false, MESSAGE_PRIORITY_NORMAL);
     pdu_len =
         npdu_encode_pdu(&Handler_Transmit_Buffer[0], src, &my_address,

bacnet-stack/demo/handler/s_ack_alarm.c

@@ -73,11 +73,7 @@ uint8_t Send_Alarm_Acknowledgement(
         invoke_id = tsm_next_free_invokeID();
     if (invoke_id) {
         /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-        my_address = *Get_Routed_Device_Address(-1);
-#else
         datalink_get_my_address(&my_address);
-#endif
         npdu_encode_npdu_data(&npdu_data, true, MESSAGE_PRIORITY_NORMAL);
         pdu_len =
             npdu_encode_pdu(&Handler_Transmit_Buffer[0], &dest, &my_address,

bacnet-stack/demo/handler/s_arfs.c

@@ -79,11 +79,7 @@ uint8_t Send_Atomic_Read_File_Stream(
         data.type.stream.fileStartPosition = fileStartPosition;
         data.type.stream.requestedOctetCount = requestedOctetCount;
         /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-        my_address = *Get_Routed_Device_Address(-1);
-#else
         datalink_get_my_address(&my_address);
-#endif
         npdu_encode_npdu_data(&npdu_data, true, MESSAGE_PRIORITY_NORMAL);
         pdu_len =
             npdu_encode_pdu(&Handler_Transmit_Buffer[0], &dest, &my_address,

bacnet-stack/demo/handler/s_awfs.c

@@ -80,11 +80,7 @@ uint8_t Send_Atomic_Write_File_Stream(
         status = octetstring_copy(&data.fileData, fileData);
         if (status) {
             /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-            my_address = *Get_Routed_Device_Address(-1);
-#else
             datalink_get_my_address(&my_address);
-#endif
             npdu_encode_npdu_data(&npdu_data, true, MESSAGE_PRIORITY_NORMAL);
             pdu_len =
                 npdu_encode_pdu(&Handler_Transmit_Buffer[0], &dest,

bacnet-stack/demo/handler/s_cevent.c

@@ -70,11 +70,7 @@ uint8_t Send_CEvent_Notify(
         invoke_id = tsm_next_free_invokeID();
     if (invoke_id) {
         /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-	    my_address = *Get_Routed_Device_Address(-1);
-#else
     	datalink_get_my_address(&my_address);
-#endif
         npdu_encode_npdu_data(&npdu_data, true, MESSAGE_PRIORITY_NORMAL);
         pdu_len =
             npdu_encode_pdu(&Handler_Transmit_Buffer[0], &dest, &my_address,

bacnet-stack/demo/handler/s_cov.c

@@ -127,11 +127,7 @@ uint8_t Send_COV_Subscribe(
     }
     if (invoke_id) {
         /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-        my_address = *Get_Routed_Device_Address(-1);
-#else
         datalink_get_my_address(&my_address);
-#endif
         npdu_encode_npdu_data(&npdu_data, true, MESSAGE_PRIORITY_NORMAL);
         pdu_len =
             npdu_encode_pdu(&Handler_Transmit_Buffer[0], &dest, &my_address,

bacnet-stack/demo/handler/s_dcc.c

@@ -83,11 +83,7 @@ uint8_t Send_Device_Communication_Control_Request(
         invoke_id = tsm_next_free_invokeID();
     if (invoke_id) {
         /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-        my_address = *Get_Routed_Device_Address(-1);
-#else
         datalink_get_my_address(&my_address);
-#endif
         npdu_encode_npdu_data(&npdu_data, true, MESSAGE_PRIORITY_NORMAL);
         pdu_len =
             npdu_encode_pdu(&Handler_Transmit_Buffer[0], &dest, &my_address,

bacnet-stack/demo/handler/s_iam.c

@@ -141,11 +141,7 @@ int iam_unicast_encode_pdu(
     memcpy(dest, src, sizeof(BACNET_ADDRESS));
     dest->net = 0;
 
-#if BAC_ROUTING
-    my_address = *Get_Routed_Device_Address(-1);
-#else
     datalink_get_my_address(&my_address);
-#endif
     /* encode the NPDU portion of the packet */
     npdu_encode_npdu_data(npdu_data, false, MESSAGE_PRIORITY_NORMAL);
     npdu_len = npdu_encode_pdu(&buffer[0], dest, &my_address, npdu_data);

bacnet-stack/demo/handler/s_lso.c

@@ -73,11 +73,7 @@ uint8_t Send_Life_Safety_Operation_Data(
         invoke_id = tsm_next_free_invokeID();
     if (invoke_id) {
         /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-        my_address = *Get_Routed_Device_Address(-1);
-#else
         datalink_get_my_address(&my_address);
-#endif
         npdu_encode_npdu_data(&npdu_data, true, MESSAGE_PRIORITY_NORMAL);
         pdu_len =
             npdu_encode_pdu(&Handler_Transmit_Buffer[0], &dest, &my_address,

bacnet-stack/demo/handler/s_ptransfer.c

@@ -78,11 +78,7 @@ uint8_t Send_Private_Transfer_Request(
         invoke_id = tsm_next_free_invokeID();
     if (invoke_id) {
         /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-        my_address = *Get_Routed_Device_Address(-1);
-#else
         datalink_get_my_address(&my_address);
-#endif
         npdu_encode_npdu_data(&npdu_data, true, MESSAGE_PRIORITY_NORMAL);
         pdu_len =
             npdu_encode_pdu(&Handler_Transmit_Buffer[0], &dest, &my_address,

bacnet-stack/demo/handler/s_rd.c

@@ -80,11 +80,7 @@ uint8_t Send_Reinitialize_Device_Request(
         invoke_id = tsm_next_free_invokeID();
     if (invoke_id) {
         /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-        my_address = *Get_Routed_Device_Address(-1);
-#else
         datalink_get_my_address(&my_address);
-#endif
         npdu_encode_npdu_data(&npdu_data, true, MESSAGE_PRIORITY_NORMAL);
         pdu_len =
             npdu_encode_pdu(&Handler_Transmit_Buffer[0], &dest, &my_address,

bacnet-stack/demo/handler/s_readrange.c

@@ -72,11 +72,7 @@ uint8_t Send_ReadRange_Request(
 
     if (invoke_id) {
         /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-        my_address = *Get_Routed_Device_Address(-1);
-#else
         datalink_get_my_address(&my_address);
-#endif
         npdu_encode_npdu_data(&npdu_data, true, MESSAGE_PRIORITY_NORMAL);
         pdu_len =
             npdu_encode_pdu(&Handler_Transmit_Buffer[0], &dest, &my_address,

bacnet-stack/demo/handler/s_rp.c

@@ -86,11 +86,7 @@ uint8_t Send_Read_Property_Request(
         invoke_id = tsm_next_free_invokeID();
     if (invoke_id) {
         /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-        my_address = *Get_Routed_Device_Address(-1);
-#else
         datalink_get_my_address(&my_address);
-#endif
         npdu_encode_npdu_data(&npdu_data, true, MESSAGE_PRIORITY_NORMAL);
         pdu_len =
             npdu_encode_pdu(&Handler_Transmit_Buffer[0], &dest, &my_address,

bacnet-stack/demo/handler/s_rpm.c

@@ -81,11 +81,7 @@ uint8_t Send_Read_Property_Multiple_Request(
         invoke_id = tsm_next_free_invokeID();
     if (invoke_id) {
         /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-        my_address = *Get_Routed_Device_Address(-1);
-#else
         datalink_get_my_address(&my_address);
-#endif
         npdu_encode_npdu_data(&npdu_data, true, MESSAGE_PRIORITY_NORMAL);
         pdu_len = npdu_encode_pdu(&pdu[0], &dest, &my_address, &npdu_data);
         /* encode the APDU portion of the packet */

bacnet-stack/demo/handler/s_wp.c

@@ -77,11 +77,7 @@ uint8_t Send_Write_Property_Request_Data(
         invoke_id = tsm_next_free_invokeID();
     if (invoke_id) {
         /* encode the NPDU portion of the packet */
-#if BAC_ROUTING
-        my_address = *Get_Routed_Device_Address(-1);
-#else
         datalink_get_my_address(&my_address);
-#endif
         npdu_encode_npdu_data(&npdu_data, true, MESSAGE_PRIORITY_NORMAL);
         pdu_len =
             npdu_encode_pdu(&Handler_Transmit_Buffer[0], &dest, &my_address,