Added Send_I_Am_Broadcast() function to Who-Is handler so that other Send_I_Am() will honor DCC Disable-Initiatiation. (#918)

src/bacnet/basic/service/h_whois.c

@@ -38,12 +38,12 @@ void handler_who_is(
     len = whois_decode_service_request(
         service_request, service_len, &low_limit, &high_limit);
     if (len == 0) {
-        Send_I_Am(&Handler_Transmit_Buffer[0]);
+        Send_I_Am_Broadcast(&Handler_Transmit_Buffer[0]);
     } else if (len != BACNET_STATUS_ERROR) {
         /* is my device id within the limits? */
         if ((Device_Object_Instance_Number() >= (uint32_t)low_limit) &&
             (Device_Object_Instance_Number() <= (uint32_t)high_limit)) {
-            Send_I_Am(&Handler_Transmit_Buffer[0]);
+            Send_I_Am_Broadcast(&Handler_Transmit_Buffer[0]);
         }
     }
 
@@ -131,7 +131,7 @@ static void check_who_is_for_routing(
             if (is_unicast) {
                 Send_I_Am_Unicast(&Handler_Transmit_Buffer[0], src);
             } else {
-                Send_I_Am(&Handler_Transmit_Buffer[0]);
+                Send_I_Am_Broadcast(&Handler_Transmit_Buffer[0]);
             }
         }
     }

src/bacnet/basic/service/s_iam.c

@@ -91,29 +91,17 @@ int iam_encode_pdu(
     return pdu_len;
 }
 
-/** Broadcast an I Am message.
+/**
- * @ingroup DMDDB
+ * @brief Send an I-Am broadcast message in response to Who-Is message
- *
  * @param buffer [in] The buffer to use for building and sending the message.
  */
-void Send_I_Am(uint8_t *buffer)
+void Send_I_Am_Broadcast(uint8_t *buffer)
 {
     int pdu_len = 0;
     BACNET_ADDRESS dest;
     int bytes_sent = 0;
     BACNET_NPDU_DATA npdu_data;
 
-#if 0
-    /* note: there is discussion in the BACnet committee
-       that we should allow a device to reply with I-Am
-       so that dynamic binding always work.  If the DCC
-       initiator loses the MAC address and routing info,
-       they can never re-enable DCC because they can't
-       find the device with WhoIs/I-Am */
-    /* are we are forbidden to send? */
-    if (!dcc_communication_enabled())
-        return 0;
-#endif
     /* encode the data */
     pdu_len = iam_encode_pdu(buffer, &dest, &npdu_data);
     /* send data */
@@ -123,6 +111,23 @@ void Send_I_Am(uint8_t *buffer)
     }
 }
 
+/**
+ * @brief Send an I-Am broadcast message NOT in response to Who-Is message
+ * @param buffer [in] The buffer to use for building and sending the message.
+ */
+void Send_I_Am(uint8_t *buffer)
+{
+    /* This function is sending a broadcast I-Am
+       that is not in response to a Who-Is.
+       This is common at device power up. */
+    if (dcc_communication_initiation_disabled()) {
+        /* we are forbidden to send */
+        debug_print("I-Am: Communication Disabled!\n");
+        return;
+    }
+    Send_I_Am_Broadcast(buffer);
+}
+
 /** Encode an I Am message to be unicast directly back to the src.
  *
  * @param buffer [in,out] The buffer to use for building the message.
@@ -177,17 +182,6 @@ void Send_I_Am_Unicast(uint8_t *buffer, const BACNET_ADDRESS *src)
     int bytes_sent = 0;
     BACNET_NPDU_DATA npdu_data;
 
-#if 0
-    /* note: there is discussion in the BACnet committee
-       that we should allow a device to reply with I-Am
-       so that dynamic binding always work.  If the DCC
-       initiator loses the MAC address and routing info,
-       they can never re-enable DCC because they can't
-       find the device with WhoIs/I-Am */
-    /* are we are forbidden to send? */
-    if (!dcc_communication_enabled())
-        return 0;
-#endif
     /* encode the data */
     pdu_len = iam_unicast_encode_pdu(buffer, src, &dest, &npdu_data);
     /* send data */

src/bacnet/basic/service/s_iam.h

@@ -39,6 +39,8 @@ int iam_encode_pdu(
 BACNET_STACK_EXPORT
 void Send_I_Am(uint8_t *buffer);
 BACNET_STACK_EXPORT
+void Send_I_Am_Broadcast(uint8_t *buffer);
+BACNET_STACK_EXPORT
 int iam_unicast_encode_pdu(
     uint8_t *buffer,
     const BACNET_ADDRESS *src,