/** * @file * @brief Send an I-Am message. * @author Steve Karg * @date 2008 * @copyright SPDX-License-Identifier: MIT */ #include #include #include /* BACnet Stack defines - first */ #include "bacnet/bacdef.h" /* BACnet Stack API */ #include "bacnet/bacdcode.h" #include "bacnet/dcc.h" #include "bacnet/npdu.h" #include "bacnet/apdu.h" #include "bacnet/iam.h" /* some demo stuff needed */ #include "bacnet/basic/binding/address.h" #include "bacnet/basic/tsm/tsm.h" #include "bacnet/basic/object/device.h" #include "bacnet/datalink/datalink.h" #include "bacnet/basic/services.h" #include "bacnet/basic/sys/debug.h" /** Send a I-Am request to a remote network for a specific device. * @param target_address [in] BACnet address of target router * @param device_id [in] Device Instance 0 - 4194303 * @param max_apdu [in] Max APDU 0-65535 * @param segmentation [in] #BACNET_SEGMENTATION enumeration * @param vendor_id [in] BACnet vendor ID 0-65535 */ void Send_I_Am_To_Network( BACNET_ADDRESS *target_address, uint32_t device_id, unsigned int max_apdu, int segmentation, uint16_t vendor_id) { int len = 0; int pdu_len = 0; int bytes_sent = 0; BACNET_NPDU_DATA npdu_data; BACNET_ADDRESS my_address; datalink_get_my_address(&my_address); /* encode the NPDU portion of the packet */ npdu_encode_npdu_data(&npdu_data, false, MESSAGE_PRIORITY_NORMAL); pdu_len = npdu_encode_pdu( &Handler_Transmit_Buffer[0], target_address, &my_address, &npdu_data); /* encode the APDU portion of the packet */ /* encode the APDU portion of the packet */ len = iam_encode_apdu( &Handler_Transmit_Buffer[pdu_len], device_id, max_apdu, segmentation, vendor_id); pdu_len += len; bytes_sent = datalink_send_pdu( target_address, &npdu_data, &Handler_Transmit_Buffer[0], pdu_len); if (bytes_sent <= 0) { debug_perror("Failed to Send I-Am Request"); } } /** Encode an I Am message to be broadcast. * @param buffer [in,out] The buffer to use for building the message. * @param dest [out] The destination address information. * @param npdu_data [out] The NPDU structure describing the message. * @return The length of the message in buffer[]. */ int iam_encode_pdu( uint8_t *buffer, BACNET_ADDRESS *dest, BACNET_NPDU_DATA *npdu_data) { int len = 0; int pdu_len = 0; BACNET_ADDRESS my_address; datalink_get_my_address(&my_address); datalink_get_broadcast_address(dest); /* encode the NPDU portion of the packet */ npdu_encode_npdu_data(npdu_data, false, MESSAGE_PRIORITY_NORMAL); pdu_len = npdu_encode_pdu(&buffer[0], dest, &my_address, npdu_data); /* encode the APDU portion of the packet */ len = iam_encode_apdu( &buffer[pdu_len], Device_Object_Instance_Number(), MAX_APDU, SEGMENTATION_NONE, Device_Vendor_Identifier()); pdu_len += len; return pdu_len; } /** * @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_Broadcast(uint8_t *buffer) { int pdu_len = 0; BACNET_ADDRESS dest; int bytes_sent = 0; BACNET_NPDU_DATA npdu_data; /* encode the data */ pdu_len = iam_encode_pdu(buffer, &dest, &npdu_data); /* send data */ bytes_sent = datalink_send_pdu(&dest, &npdu_data, &buffer[0], pdu_len); if (bytes_sent <= 0) { debug_perror("Failed to Send I-Am Reply"); } } /** * @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. * @param src [in] The source address information. If the src address is not * given, the dest address will be a broadcast address. * @param dest [out] The destination address information. * @param npdu_data [out] The NPDU structure describing the message. * @return The length of the message in buffer[]. */ int iam_unicast_encode_pdu( uint8_t *buffer, const BACNET_ADDRESS *src, BACNET_ADDRESS *dest, BACNET_NPDU_DATA *npdu_data) { int npdu_len = 0; int apdu_len = 0; int pdu_len = 0; BACNET_ADDRESS my_address; /* The destination will be the same as the src, so copy it over. */ bacnet_address_copy(dest, src); /* dest->net = 0; - no, must direct back to src->net to meet BTL tests */ datalink_get_my_address(&my_address); /* 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); /* encode the APDU portion of the packet */ apdu_len = iam_encode_apdu( &buffer[npdu_len], Device_Object_Instance_Number(), MAX_APDU, SEGMENTATION_NONE, Device_Vendor_Identifier()); pdu_len = npdu_len + apdu_len; return pdu_len; } /** Send an I-Am message by unicasting directly back to the src. * @ingroup DMDDB * @note As of Addendum 135-2008q-1, unicast responses are allowed; * in modern firewalled corporate networks, this may be the * only type of response that will reach the source on * another subnet (without using the BBMD).
* However, some BACnet routers may not correctly handle this message. * * @param buffer [in] The buffer to use for building and sending the message. * @param src [in] The source address information from service handler. */ void Send_I_Am_Unicast(uint8_t *buffer, const BACNET_ADDRESS *src) { int pdu_len = 0; BACNET_ADDRESS dest; int bytes_sent = 0; BACNET_NPDU_DATA npdu_data; /* encode the data */ pdu_len = iam_unicast_encode_pdu(buffer, src, &dest, &npdu_data); /* send data */ bytes_sent = datalink_send_pdu(&dest, &npdu_data, &buffer[0], pdu_len); if (bytes_sent <= 0) { debug_perror("Failed to Send I-Am Reply"); } }