/** Functions related to TeleCommand acceptance. * * @file * @author P. LEROY * * A group of functions to handle TeleCommands parsing.\n * */ #include "tc_acceptance.h" #include unsigned int lookUpTableForCRC[256]; //********************** // GENERAL USE FUNCTIONS unsigned int Crc_opt( unsigned char D, unsigned int Chk) { /** This function generate the CRC for one byte and returns the value of the new syndrome. * * @param D is the current byte of data. * @param Chk is the current syndrom value. * * @return the value of the new syndrome on two bytes. * */ return(((Chk << 8) & 0xff00)^lookUpTableForCRC [(((Chk >> 8)^D) & 0x00ff)]); } void initLookUpTableForCRC( void ) { /** This function is used to initiates the look-up table for fast CRC computation. * * The global table lookUpTableForCRC[256] is initiated. * */ unsigned int i; unsigned int tmp; for (i=0; i<256; i++) { tmp = 0; if((i & 1) != 0) { tmp = tmp ^ 0x1021; } if((i & 2) != 0) { tmp = tmp ^ 0x2042; } if((i & 4) != 0) { tmp = tmp ^ 0x4084; } if((i & 8) != 0) { tmp = tmp ^ 0x8108; } if((i & 16) != 0) { tmp = tmp ^ 0x1231; } if((i & 32) != 0) { tmp = tmp ^ 0x2462; } if((i & 64) != 0) { tmp = tmp ^ 0x48c4; } if((i & 128) != 0) { tmp = tmp ^ 0x9188; } lookUpTableForCRC[i] = tmp; } } void GetCRCAsTwoBytes(unsigned char* data, unsigned char* crcAsTwoBytes, unsigned int sizeOfData) { /** This function calculates a two bytes Cyclic Redundancy Code. * * @param data points to a buffer containing the data on which to compute the CRC. * @param crcAsTwoBytes points points to a two bytes buffer in which the CRC is stored. * @param sizeOfData is the number of bytes of *data* used to compute the CRC. * * The specification of the Cyclic Redundancy Code is described in the following document: ECSS-E-70-41-A. * */ unsigned int Chk; int j; Chk = 0xffff; // reset the syndrom to all ones for (j=0; j> 8); crcAsTwoBytes[1] = (unsigned char) (Chk & 0x00ff); } //********************* // ACCEPTANCE FUNCTIONS int tc_parser(ccsdsTelecommandPacket_t * TCPacket, unsigned int estimatedPacketLength, unsigned char *computed_CRC) { /** This function parses TeleCommands. * * @param TC points to the TeleCommand that will be parsed. * @param estimatedPacketLength is the PACKET_LENGTH field calculated from the effective length of the received packet. * * @return Status code of the parsing. * * The parsing checks: * - process id * - category * - length: a global check is performed and a per subtype check also * - type * - subtype * - crc * */ int status; int status_crc; unsigned char pid; unsigned char category; unsigned int packetLength; unsigned char packetType; unsigned char packetSubtype; unsigned char sid; status = CCSDS_TM_VALID; // APID check *** APID on 2 bytes pid = ((TCPacket->packetID[0] & 0x07)<<4) + ( (TCPacket->packetID[1]>>4) & 0x0f ); // PID = 11 *** 7 bits xxxxx210 7654xxxx category = (TCPacket->packetID[1] & 0x0f); // PACKET_CATEGORY = 12 *** 4 bits xxxxxxxx xxxx3210 packetLength = (TCPacket->packetLength[0] * 256) + TCPacket->packetLength[1]; packetType = TCPacket->serviceType; packetSubtype = TCPacket->serviceSubType; sid = TCPacket->sourceID; if ( pid != CCSDS_PROCESS_ID ) // CHECK THE PROCESS ID { status = ILLEGAL_APID; } if (status == CCSDS_TM_VALID) // CHECK THE CATEGORY { if ( category != CCSDS_PACKET_CATEGORY ) { status = ILLEGAL_APID; } } if (status == CCSDS_TM_VALID) // CHECK THE PACKET_LENGTH FIELD AND THE ESTIMATED PACKET_LENGTH COMPLIANCE { if (packetLength != estimatedPacketLength ) { status = WRONG_LEN_PKT; } } if (status == CCSDS_TM_VALID) // CHECK THAT THE PACKET DOES NOT EXCEED THE MAX SIZE { if ( packetLength >= CCSDS_TC_PKT_MAX_SIZE ) { status = WRONG_LEN_PKT; } } if (status == CCSDS_TM_VALID) // CHECK THE TYPE { status = tc_check_type( packetType ); } if (status == CCSDS_TM_VALID) // CHECK THE SUBTYPE { status = tc_check_type_subtype( packetType, packetSubtype ); } if (status == CCSDS_TM_VALID) // CHECK THE SID { status = tc_check_sid( sid ); } if (status == CCSDS_TM_VALID) // CHECK THE SUBTYPE AND LENGTH COMPLIANCE { status = tc_check_length( packetSubtype, packetLength ); } status_crc = tc_check_crc( TCPacket, estimatedPacketLength, computed_CRC ); if (status == CCSDS_TM_VALID ) // CHECK CRC { status = status_crc; } return status; } int tc_check_type( unsigned char packetType ) { /** This function checks that the type of a TeleCommand is valid. * * @param packetType is the type to check. * * @return Status code CCSDS_TM_VALID or ILL_TYPE. * */ int status; if ( (packetType == TC_TYPE_GEN) || (packetType == TC_TYPE_TIME)) { status = CCSDS_TM_VALID; } else { status = ILL_TYPE; } return status; } int tc_check_type_subtype( unsigned char packetType, unsigned char packetSubType ) { /** This function checks that the subtype of a TeleCommand is valid and coherent with the type. * * @param packetType is the type of the TC. * @param packetSubType is the subtype to check. * * @return Status code CCSDS_TM_VALID or ILL_SUBTYPE. * */ int status; switch(packetType) { case TC_TYPE_GEN: if ( (packetSubType == TC_SUBTYPE_RESET) || (packetSubType == TC_SUBTYPE_LOAD_COMM) || (packetSubType == TC_SUBTYPE_LOAD_NORM) || (packetSubType == TC_SUBTYPE_LOAD_BURST) || (packetSubType == TC_SUBTYPE_LOAD_SBM1) || (packetSubType == TC_SUBTYPE_LOAD_SBM2) || (packetSubType == TC_SUBTYPE_DUMP) || (packetSubType == TC_SUBTYPE_ENTER) || (packetSubType == TC_SUBTYPE_UPDT_INFO) || (packetSubType == TC_SUBTYPE_EN_CAL) || (packetSubType == TC_SUBTYPE_DIS_CAL) || (packetSubType == TC_SUBTYPE_LOAD_K) || (packetSubType == TC_SUBTYPE_DUMP_K) || (packetSubType == TC_SUBTYPE_LOAD_FBINS) ) { status = CCSDS_TM_VALID; } else { status = ILL_SUBTYPE; } break; case TC_TYPE_TIME: if (packetSubType == TC_SUBTYPE_UPDT_TIME) { status = CCSDS_TM_VALID; } else { status = ILL_SUBTYPE; } break; default: status = ILL_SUBTYPE; break; } return status; } int tc_check_sid( unsigned char sid ) { /** This function checks that the sid of a TeleCommand is valid. * * @param sid is the sid to check. * * @return Status code CCSDS_TM_VALID or CORRUPTED. * */ int status; if ( (sid == SID_TC_MISSION_TIMELINE) || (sid == SID_TC_TC_SEQUENCES) || (sid == SID_TC_RECOVERY_ACTION_CMD) || (sid == SID_TC_BACKUP_MISSION_TIMELINE) || (sid == SID_TC_DIRECT_CMD) || (sid == SID_TC_SPARE_GRD_SRC1) || (sid == SID_TC_SPARE_GRD_SRC2) || (sid == SID_TC_OBCP) || (sid == SID_TC_SYSTEM_CONTROL) || (sid == SID_TC_AOCS) || (sid == SID_TC_RPW_INTERNAL)) { status = CCSDS_TM_VALID; } else { status = WRONG_SRC_ID; } return status; } int tc_check_length( unsigned char packetSubType, unsigned int length ) { /** This function checks that the subtype and the length are compliant. * * @param packetSubType is the subtype to check. * @param length is the length to check. * * @return Status code CCSDS_TM_VALID or ILL_TYPE. * */ int status; status = LFR_SUCCESSFUL; switch(packetSubType) { case TC_SUBTYPE_RESET: if (length!=(TC_LEN_RESET-CCSDS_TC_TM_PACKET_OFFSET)) { status = WRONG_LEN_PKT; } else { status = CCSDS_TM_VALID; } break; case TC_SUBTYPE_LOAD_COMM: if (length!=(TC_LEN_LOAD_COMM-CCSDS_TC_TM_PACKET_OFFSET)) { status = WRONG_LEN_PKT; } else { status = CCSDS_TM_VALID; } break; case TC_SUBTYPE_LOAD_NORM: if (length!=(TC_LEN_LOAD_NORM-CCSDS_TC_TM_PACKET_OFFSET)) { status = WRONG_LEN_PKT; } else { status = CCSDS_TM_VALID; } break; case TC_SUBTYPE_LOAD_BURST: if (length!=(TC_LEN_LOAD_BURST-CCSDS_TC_TM_PACKET_OFFSET)) { status = WRONG_LEN_PKT; } else { status = CCSDS_TM_VALID; } break; case TC_SUBTYPE_LOAD_SBM1: if (length!=(TC_LEN_LOAD_SBM1-CCSDS_TC_TM_PACKET_OFFSET)) { status = WRONG_LEN_PKT; } else { status = CCSDS_TM_VALID; } break; case TC_SUBTYPE_LOAD_SBM2: if (length!=(TC_LEN_LOAD_SBM2-CCSDS_TC_TM_PACKET_OFFSET)) { status = WRONG_LEN_PKT; } else { status = CCSDS_TM_VALID; } break; case TC_SUBTYPE_DUMP: if (length!=(TC_LEN_DUMP-CCSDS_TC_TM_PACKET_OFFSET)) { status = WRONG_LEN_PKT; } else { status = CCSDS_TM_VALID; } break; case TC_SUBTYPE_ENTER: if (length!=(TC_LEN_ENTER-CCSDS_TC_TM_PACKET_OFFSET)) { status = WRONG_LEN_PKT; } else { status = CCSDS_TM_VALID; } break; case TC_SUBTYPE_UPDT_INFO: if (length!=(TC_LEN_UPDT_INFO-CCSDS_TC_TM_PACKET_OFFSET)) { status = WRONG_LEN_PKT; } else { status = CCSDS_TM_VALID; } break; case TC_SUBTYPE_EN_CAL: if (length!=(TC_LEN_EN_CAL-CCSDS_TC_TM_PACKET_OFFSET)) { status = WRONG_LEN_PKT; } else { status = CCSDS_TM_VALID; } break; case TC_SUBTYPE_DIS_CAL: if (length!=(TC_LEN_DIS_CAL-CCSDS_TC_TM_PACKET_OFFSET)) { status = WRONG_LEN_PKT; } else { status = CCSDS_TM_VALID; } break; case TC_SUBTYPE_LOAD_K: if (length!=(TC_LEN_LOAD_K-CCSDS_TC_TM_PACKET_OFFSET)) { status = WRONG_LEN_PKT; } else { status = CCSDS_TM_VALID; } break; case TC_SUBTYPE_DUMP_K: if (length!=(TC_LEN_DUMP_K-CCSDS_TC_TM_PACKET_OFFSET)) { status = WRONG_LEN_PKT; } else { status = CCSDS_TM_VALID; } break; case TC_SUBTYPE_LOAD_FBINS: if (length!=(TC_LEN_LOAD_FBINS-CCSDS_TC_TM_PACKET_OFFSET)) { status = WRONG_LEN_PKT; } else { status = CCSDS_TM_VALID; } break; case TC_SUBTYPE_UPDT_TIME: if (length!=(TC_LEN_UPDT_TIME-CCSDS_TC_TM_PACKET_OFFSET)) { status = WRONG_LEN_PKT; } else { status = CCSDS_TM_VALID; } break; default: // if the subtype is not a legal value, return ILL_SUBTYPE status = ILL_SUBTYPE; break ; } return status; } int tc_check_crc( ccsdsTelecommandPacket_t * TCPacket, unsigned int length, unsigned char *computed_CRC ) { /** This function checks the CRC validity of the corresponding TeleCommand packet. * * @param TCPacket points to the TeleCommand packet to check. * @param length is the length of the TC packet. * * @return Status code CCSDS_TM_VALID or INCOR_CHECKSUM. * */ int status; unsigned char * CCSDSContent; CCSDSContent = (unsigned char*) TCPacket->packetID; GetCRCAsTwoBytes(CCSDSContent, computed_CRC, length + CCSDS_TC_TM_PACKET_OFFSET - 2); // 2 CRC bytes removed from the calculation of the CRC if (computed_CRC[0] != CCSDSContent[length + CCSDS_TC_TM_PACKET_OFFSET -2]) { status = INCOR_CHECKSUM; } else if (computed_CRC[1] != CCSDSContent[length + CCSDS_TC_TM_PACKET_OFFSET -1]) { status = INCOR_CHECKSUM; } else { status = CCSDS_TM_VALID; } return status; }