/************************************************************************** * * Copyright (C) 2005 Steve Karg * * SPDX-License-Identifier: MIT * *********************************************************************/ #include #include #include #include /* BACnet Stack defines - first */ #include "bacnet/bacdef.h" /* BACnet Stack API */ #include "bacnet/bacdcode.h" #include "bacnet/bacerror.h" #include "bacnet/apdu.h" #include "bacnet/npdu.h" #include "bacnet/abort.h" #include "bacnet/reject.h" #include "bacnet/wp.h" /* basic objects, services, TSM, and datalink */ #include "bacnet/basic/object/device.h" #include "bacnet/basic/tsm/tsm.h" #include "bacnet/basic/services.h" #include "bacnet/basic/sys/debug.h" #include "bacnet/datalink/datalink.h" /** @file h_wp.c Handles Write Property requests. */ /** * @brief Handler for a WriteProperty Service request when the * property is a NULL type and the property is not commandable * * 15.9.2 WriteProperty Service Procedure * * If an attempt is made to relinquish a property that is * not commandable and for which Null is not a supported * datatype, if no other error conditions exist, * the property shall not be changed, and the write shall * be considered successful. * * @note There was an interpretation request in April 2025 that clarifies * that the NULL bypass is only for present-value property of objects that * optionally support a priority array but don't implement it. * See 135-2024-19.2.1.1 Commandable Properties for the list of commandable * properties of specific objects. * * @param wp_data [in] The WriteProperty data structure * @return true if the write shall be considered successful */ static bool handler_write_property_relinquish_bypass(BACNET_WRITE_PROPERTY_DATA *wp_data) { bool status = false; #if BACNET_PROTOCOL_REVISION >= 21 status = write_property_relinquish_bypass( wp_data, Device_Objects_Property_List_Member); #endif return status; } /** Handler for a WriteProperty Service request. * @ingroup DSWP * This handler will be invoked by apdu_handler() if it has been enabled * by a call to apdu_set_confirmed_handler(). * This handler builds a response packet, which is * - an Abort if * - the message is segmented * - if decoding fails * - an ACK if Device_Write_Property() succeeds * - an Error if Device_Write_Property() fails * or there isn't enough room in the APDU to fit the data. * * @param service_request [in] The contents of the service request. * @param service_len [in] The length of the service_request. * @param src [in] BACNET_ADDRESS of the source of the message * @param service_data [in] The BACNET_CONFIRMED_SERVICE_DATA information * decoded from the APDU header of this message. */ void handler_write_property( uint8_t *service_request, uint16_t service_len, BACNET_ADDRESS *src, BACNET_CONFIRMED_SERVICE_DATA *service_data) { BACNET_WRITE_PROPERTY_DATA wp_data; int len = 0; bool bcontinue = true; bool success = false; int pdu_len = 0; BACNET_NPDU_DATA npdu_data; int bytes_sent = 0; BACNET_ADDRESS my_address; /* encode the NPDU portion of the packet */ datalink_get_my_address(&my_address); npdu_encode_npdu_data(&npdu_data, false, service_data->priority); pdu_len = npdu_encode_pdu( &Handler_Transmit_Buffer[0], src, &my_address, &npdu_data); debug_print("WP: Received Request!\n"); if (service_len == 0) { len = reject_encode_apdu( &Handler_Transmit_Buffer[pdu_len], service_data->invoke_id, REJECT_REASON_MISSING_REQUIRED_PARAMETER); debug_print("WP: Missing Required Parameter. Sending Reject!\n"); bcontinue = false; } #if !BACNET_SEGMENTATION_ENABLED else if (service_data->segmented_message) { len = abort_encode_apdu( &Handler_Transmit_Buffer[pdu_len], service_data->invoke_id, ABORT_REASON_SEGMENTATION_NOT_SUPPORTED, true); debug_print("WP: Segmented message. Sending Abort!\n"); bcontinue = false; } #endif if (bcontinue) { /* decode the service request only */ len = wp_decode_service_request(service_request, service_len, &wp_data); if (len > 0) { debug_fprintf( stderr, "WP: type=%lu instance=%lu property=%lu priority=%lu " "index=%ld\n", (unsigned long)wp_data.object_type, (unsigned long)wp_data.object_instance, (unsigned long)wp_data.object_property, (unsigned long)wp_data.priority, (long)wp_data.array_index); } else { debug_print("WP: Unable to decode Request!\n"); } /* bad decoding or something we didn't understand - send an abort */ if (len <= 0) { len = abort_encode_apdu( &Handler_Transmit_Buffer[pdu_len], service_data->invoke_id, ABORT_REASON_OTHER, true); debug_print("WP: Bad Encoding. Sending Abort!\n"); bcontinue = false; } if (bcontinue) { success = handler_write_property_relinquish_bypass(&wp_data); if (success) { /* this object property is not commandable, and therefore, not able to be relinquished, so it "shall not be changed, and the write shall be considered successful." */ } else { if (write_property_bacnet_array_valid(&wp_data)) { success = Device_Write_Property(&wp_data); } } if (success) { len = encode_simple_ack( &Handler_Transmit_Buffer[pdu_len], service_data->invoke_id, SERVICE_CONFIRMED_WRITE_PROPERTY); debug_print("WP: Sending Simple Ack!\n"); } else { len = bacerror_encode_apdu( &Handler_Transmit_Buffer[pdu_len], service_data->invoke_id, SERVICE_CONFIRMED_WRITE_PROPERTY, wp_data.error_class, wp_data.error_code); debug_print("WP: Sending Error!\n"); } } } /* Send PDU */ pdu_len += len; bytes_sent = datalink_send_pdu( src, &npdu_data, &Handler_Transmit_Buffer[0], pdu_len); if (bytes_sent <= 0) { debug_perror("WP: Failed to send PDU"); } return; } /** * @brief Perform basic validation of Write Property argument based on * the assumption that it is a string. Check for correct data type, * correct encoding (fixed here as ANSI X34),correct length, and * finally if it is allowed to be empty. * * @param pValue Pointer to the application data value representing the string. * @param iMaxLen Maximum string length allowed. * @param bEmptyAllowed true, if empty strings shall be allowed. * @param pErrorClass Pointer to a variable taking the error class. * @param pErrorCode Pointer to a variable taking the error code. * * @return True on success, false otherwise. */ bool WPValidateString( const BACNET_APPLICATION_DATA_VALUE *pValue, int iMaxLen, bool bEmptyAllowed, BACNET_ERROR_CLASS *pErrorClass, BACNET_ERROR_CODE *pErrorCode) { bool bResult; /* Save on a bit of code duplication by pre selecting the most * common outcomes from the tests (not necessarily the most likely * outcome of the tests). */ bResult = false; *pErrorClass = ERROR_CLASS_PROPERTY; if (pValue->tag == BACNET_APPLICATION_TAG_CHARACTER_STRING) { if (characterstring_encoding(&pValue->type.Character_String) == CHARACTER_ANSI_X34) { if ((bEmptyAllowed == false) && (characterstring_length(&pValue->type.Character_String) == 0)) { *pErrorCode = ERROR_CODE_VALUE_OUT_OF_RANGE; } else if ( (bEmptyAllowed == false) && (!characterstring_printable(&pValue->type.Character_String))) { /* assumption: non-empty also means must be "printable" */ *pErrorCode = ERROR_CODE_VALUE_OUT_OF_RANGE; } else if ( characterstring_length(&pValue->type.Character_String) > (uint16_t)iMaxLen) { *pErrorClass = ERROR_CLASS_RESOURCES; *pErrorCode = ERROR_CODE_NO_SPACE_TO_WRITE_PROPERTY; } else { bResult = true; /* It's all good! */ } } else { *pErrorCode = ERROR_CODE_CHARACTER_SET_NOT_SUPPORTED; } } else { *pErrorCode = ERROR_CODE_INVALID_DATA_TYPE; } return (bResult); } /** Perform simple validation of type of Write Property argument based * the expected type vs the actual. Set up error response if the * validation fails. Cuts out reams of repeated code in the object code. */ bool WPValidateArgType( const BACNET_APPLICATION_DATA_VALUE *pValue, uint8_t ucExpectedTag, BACNET_ERROR_CLASS *pErrorClass, BACNET_ERROR_CODE *pErrorCode) { bool bResult; /* * start out assuming success and only set up error * response if validation fails. */ bResult = true; if (pValue->tag != ucExpectedTag) { bResult = false; *pErrorClass = ERROR_CLASS_PROPERTY; *pErrorCode = ERROR_CODE_INVALID_DATA_TYPE; } return (bResult); }