Had an issue where Original_Broadcast requests were not responded to with Original_Broadcast packets; this is a fix for that.

bacnet-stack/src/bip.c

@@ -209,14 +209,23 @@ int bip_send_pdu(
     return bytes_sent;
 }
 
-/* receives a BACnet/IP packet */
+/** Implementation of the receive() function for BACnet/IP; receives one 
-/* returns the number of octets in the PDU, or zero on failure */
+ * packet, verifies its BVLC header, and removes the BVLC header from 
+ * the PDU data before returning.
+ * 
+ * @param src [out] Source of the packet - who should receive any response.
+ * @param pdu [out] A buffer to hold the PDU portion of the received packet,
+ * 					after the BVLC portion has been stripped off.
+ * @param max_pdu [in] Size of the pdu[] buffer.
+ * @param timeout [in] The number of milliseconds to wait for a packet.
+ * @return The number of octets (remaining) in the PDU, or zero on failure.
+ */
 uint16_t bip_receive(
     BACNET_ADDRESS * src,       /* source address */
     uint8_t * pdu,      /* PDU data */
     uint16_t max_pdu,   /* amount of space available in the PDU  */
     unsigned timeout)
-{       /* number of milliseconds to wait for a packet */
+{       
     int received_bytes = 0;
     uint16_t pdu_len = 0;       /* return value */
     fd_set read_fds;
@@ -274,10 +283,20 @@ uint16_t bip_receive(
             fprintf(stderr, "BIP: src is me. Discarded!\n");
 #endif
         } else {
-            /* data in src->mac[] is in network format */
+            /* If this was an Original_Broadcast, ensure that
-            src->mac_len = 6;
+             * the response gets bcast back by this:
-            memcpy(&src->mac[0], &sin.sin_addr.s_addr, 4);
+             */
-            memcpy(&src->mac[4], &sin.sin_port, 2);
+            if (pdu[1] == BVLC_ORIGINAL_BROADCAST_NPDU) {
+            	src->net = BACNET_BROADCAST_NETWORK;
+                src->mac_len = 0;
+            } else {
+           		src->net = 0;
+                /* data in src->mac[] is in network format */
+                src->mac_len = 6;
+                memcpy(&src->mac[0], &sin.sin_addr.s_addr, 4);
+                memcpy(&src->mac[4], &sin.sin_port, 2);
+            }
+            
             /* FIXME: check destination address */
             /* see if it is broadcast or for us */
             /* decode the length of the PDU - length is inclusive of BVLC */

bacnet-stack/src/npdu.c

@@ -409,7 +409,12 @@ int npdu_decode(
                 }
             }
         } else if (src) {
-            src->net = 0;
+        	/* Clear the net number, with one exception: if the receive() 
+        	 * function set it to BACNET_BROADCAST_NETWORK, (eg, for 
+        	 * BVLC_ORIGINAL_BROADCAST_NPDU) then don't stomp on that.
+        	 */
+        	if ( src->net != BACNET_BROADCAST_NETWORK )
+        		src->net = 0;
             src->len = 0;
             for (i = 0; i < MAX_MAC_LEN; i++) {
                 src->adr[i] = 0;