zeek/src/analyzer/protocol/modbus/modbus-protocol.pac
2023-08-08 10:54:33 -07:00

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JavaScript

#
# The development of Zeek's Modbus analyzer has been made possible thanks to
# the support of the Ministry of Security and Justice of the Kingdom of the
# Netherlands within the projects of Hermes, Castor and Midas.
#
# Useful references: http://www.modbus.org/docs/Modbus_Application_Protocol_V1_1b.pdf
# http://www.simplymodbus.ca/faq.htm
enum function_codes {
# Standard functions
READ_COILS = 0x01,
READ_DISCRETE_INPUTS = 0x02,
READ_HOLDING_REGISTERS = 0x03,
READ_INPUT_REGISTERS = 0x04,
WRITE_SINGLE_COIL = 0x05,
WRITE_SINGLE_REGISTER = 0x06,
# READ_EXCEPTION_STATUS = 0x07,
# DIAGNOSTICS = 0x08,
# GET_COMM_EVENT_COUNTER = 0x0B,
# GET_COMM_EVENT_LOG = 0x0C,
WRITE_MULTIPLE_COILS = 0x0F,
WRITE_MULTIPLE_REGISTERS = 0x10,
# REPORT_SLAVE_ID = 0x11,
READ_FILE_RECORD = 0x14,
WRITE_FILE_RECORD = 0x15,
MASK_WRITE_REGISTER = 0x16,
READ_WRITE_MULTIPLE_REGISTERS = 0x17,
READ_FIFO_QUEUE = 0x18,
ENCAP_INTERFACE_TRANSPORT = 0x2B,
# Machine/vendor/network specific functions
PROGRAM_484 = 0x09,
POLL_484 = 0x0A,
PROGRAM_584_984 = 0x0D,
POLL_584_984 = 0x0E,
PROGRAM_884_U84 = 0x12,
RESET_COMM_LINK_884_U84 = 0x13,
PROGRAM_CONCEPT = 0x28,
FIRMWARE_REPLACEMENT = 0x7D,
PROGRAM_584_984_2 = 0x7E,
REPORT_LOCAL_ADDRESS = 0x7F,
# Exceptions (not really function codes but they are used similarly)
READ_COILS_EXCEPTION = 0x81,
READ_DISCRETE_INPUTS_EXCEPTION = 0x82,
READ_HOLDING_REGISTERS_EXCEPTION = 0x83,
READ_INPUT_REGISTERS_EXCEPTION = 0x84,
WRITE_SINGLE_COIL_EXCEPTION = 0x85,
WRITE_SINGLE_REGISTER_EXCEPTION = 0x86,
READ_EXCEPTION_STATUS_EXCEPTION = 0x87,
WRITE_MULTIPLE_COILS_EXCEPTION = 0x8F,
WRITE_MULTIPLE_REGISTERS_EXCEPTION = 0x90,
READ_FILE_RECORD_EXCEPTION = 0x94,
WRITE_FILE_RECORD_EXCEPTION = 0x95,
MASK_WRITE_REGISTER_EXCEPTION = 0x96,
READ_WRITE_MULTIPLE_REGISTERS_EXCEPTION = 0x97,
READ_FIFO_QUEUE_EXCEPTION = 0x98,
};
# Main Modbus/TCP PDU
type ModbusTCP_PDU(is_orig: bool) = record {
header: ModbusTCP_TransportHeader;
body: case is_orig of {
true -> request: ModbusTCP_Request(header);
false -> response: ModbusTCP_Response(header);
};
} &let {
deliver: bool = $context.flow.deliver_ModbusTCP_PDU(this);
} &length=header.len+6, &byteorder=bigendian;
type ModbusTCP_TransportHeader = record {
tid: uint16; # Transaction identifier
pid: uint16; # Protocol identifier
len: uint16; # Length of everything after this field
uid: uint8; # Unit identifier (previously 'slave address')
fc: uint8; # MODBUS function code (see function_codes enum)
} &byteorder=bigendian, &let {
deliver: bool = $context.flow.deliver_message(this);
};
type ModbusTCP_Request(header: ModbusTCP_TransportHeader) = case header.fc of {
READ_COILS -> readCoils: ReadCoilsRequest(header);
READ_DISCRETE_INPUTS -> readDiscreteInputs: ReadDiscreteInputsRequest(header);
READ_HOLDING_REGISTERS -> readHoldingRegisters: ReadHoldingRegistersRequest(header);
READ_INPUT_REGISTERS -> readInputRegisters: ReadInputRegistersRequest(header);
WRITE_SINGLE_COIL -> writeSingleCoil: WriteSingleCoilRequest(header);
WRITE_SINGLE_REGISTER -> writeSingleRegister: WriteSingleRegisterRequest(header);
#READ_EXCEPTION_STATUS -> readExceptionStatus: ReadExceptionStatusRequest(header);
#DIAGNOSTICS -> diagnostics: DiagnosticsRequest(header);
#GET_COMM_EVENT_COUNTER -> getCommEventCounter: GetCommEventCounterRequest(header);
#GET_COMM_EVENT_LOG -> getCommEventLog: GetCommEventLogRequest(header);
WRITE_MULTIPLE_COILS -> writeMultipleCoils: WriteMultipleCoilsRequest(header);
WRITE_MULTIPLE_REGISTERS -> writeMultRegisters: WriteMultipleRegistersRequest(header);
#REPORT_SLAVE_ID
READ_FILE_RECORD -> readFileRecord: ReadFileRecordRequest(header);
WRITE_FILE_RECORD -> writeFileRecord: WriteFileRecordRequest(header);
MASK_WRITE_REGISTER -> maskWriteRegister: MaskWriteRegisterRequest(header);
READ_WRITE_MULTIPLE_REGISTERS -> readWriteMultipleRegisters: ReadWriteMultipleRegistersRequest(header);
READ_FIFO_QUEUE -> readFIFOQueue: ReadFIFOQueueRequest(header);
#ENCAP_INTERFACE_TRANSPORT
# All the rest
default -> unknown: bytestring &restofdata;
};
# Responses
#
type ModbusTCP_Response(header: ModbusTCP_TransportHeader) = case header.fc of {
READ_COILS -> readCoils: ReadCoilsResponse(header);
READ_DISCRETE_INPUTS -> readDiscreteInputs: ReadDiscreteInputsResponse(header);
READ_HOLDING_REGISTERS -> readHoldingRegisters: ReadHoldingRegistersResponse(header);
READ_INPUT_REGISTERS -> readInputRegisters: ReadInputRegistersResponse(header);
WRITE_SINGLE_COIL -> writeSingleCoil: WriteSingleCoilResponse(header);
WRITE_SINGLE_REGISTER -> writeSingleRegister: WriteSingleRegisterResponse(header);
#READ_EXCEPTION_STATUS -> readExceptionStatus: ReadExceptionStatusResponse(header);
#DIAGNOSTICS -> diagnostics: DiagnosticsResponse(header);
#GET_COMM_EVENT_COUNTER -> getCommEventCounter: GetCommEventCounterResponse(header);
#GET_COMM_EVENT_LOG -> getCommEventLog: GetCommEventLogResponse(header);
WRITE_MULTIPLE_COILS -> writeMultipleCoils: WriteMultipleCoilsResponse(header);
WRITE_MULTIPLE_REGISTERS -> writeMultRegisters: WriteMultipleRegistersResponse(header);
#REPORT_SLAVE_ID
READ_FILE_RECORD -> readFileRecord: ReadFileRecordResponse(header);
WRITE_FILE_RECORD -> writeFileRecord: WriteFileRecordResponse(header);
MASK_WRITE_REGISTER -> maskWriteRegister: MaskWriteRegisterResponse(header);
READ_WRITE_MULTIPLE_REGISTERS -> readWriteMultipleRegisters: ReadWriteMultipleRegistersResponse(header);
READ_FIFO_QUEUE -> readFIFOQueue: ReadFIFOQueueResponse(header);
# Exceptions
READ_HOLDING_REGISTERS_EXCEPTION -> readHoldingRegistersException: Exception(header);
WRITE_MULTIPLE_REGISTERS_EXCEPTION -> writeMultRegistersException: Exception(header);
READ_COILS_EXCEPTION -> readCoilsException: Exception(header);
READ_DISCRETE_INPUTS_EXCEPTION -> readDiscreteInputsException: Exception(header);
READ_INPUT_REGISTERS_EXCEPTION -> readInputRegistersException: Exception(header);
WRITE_SINGLE_COIL_EXCEPTION -> writeCoilException: Exception(header);
WRITE_SINGLE_REGISTER_EXCEPTION -> writeSingleRegisterException: Exception(header);
READ_EXCEPTION_STATUS_EXCEPTION -> readExceptionStatusException: Exception(header);
WRITE_MULTIPLE_COILS_EXCEPTION -> forceMultipleCoilsException: Exception(header);
READ_FILE_RECORD_EXCEPTION -> readGeneralReferenceException: Exception(header);
WRITE_FILE_RECORD_EXCEPTION -> writeGeneralReferenceException: Exception(header);
MASK_WRITE_REGISTER_EXCEPTION -> maskWriteRegisterException: Exception(header);
READ_WRITE_MULTIPLE_REGISTERS_EXCEPTION -> readWriteRegistersException: Exception(header);
READ_FIFO_QUEUE_EXCEPTION -> readFIFOQueueException: Exception(header);
# All the rest
default -> unknown: bytestring &restofdata;
};
type Exception(header: ModbusTCP_TransportHeader) = record {
code: uint8;
} &let {
deliver: bool = $context.flow.deliver_Exception(header, this);
};
# REQUEST FC=1
type ReadCoilsRequest(header: ModbusTCP_TransportHeader) = record {
start_address: uint16;
quantity: uint16; # &check(quantity <= 2000);
} &let {
deliver: bool = $context.flow.deliver_ReadCoilsRequest(header, this);
} &byteorder=bigendian;
# RESPONSE FC=1
type ReadCoilsResponse(header: ModbusTCP_TransportHeader) = record {
byte_count: uint8;
bits: bytestring &length=byte_count;
} &let {
deliver: bool = $context.flow.deliver_ReadCoilsResponse(header, this);
} &byteorder=bigendian;
# REQUEST FC=2
type ReadDiscreteInputsRequest(header: ModbusTCP_TransportHeader) = record {
start_address: uint16;
quantity: uint16; # &check(quantity <= 2000);
} &let {
deliver: bool = $context.flow.deliver_ReadDiscreteInputsRequest(header, this);
} &byteorder=bigendian;
# RESPONSE FC=2
type ReadDiscreteInputsResponse(header: ModbusTCP_TransportHeader) = record {
byte_count: uint8;
bits: bytestring &length=byte_count;
} &let {
deliver: bool = $context.flow.deliver_ReadDiscreteInputsResponse(header, this);
} &byteorder=bigendian;
# REQUEST FC=3
type ReadHoldingRegistersRequest(header: ModbusTCP_TransportHeader) = record {
start_address: uint16;
quantity: uint16; # &check(quantity <= 125);
} &let {
deliver: bool = $context.flow.deliver_ReadHoldingRegistersRequest(header, this);
} &byteorder=bigendian;
# RESPONSE FC=3
type ReadHoldingRegistersResponse(header: ModbusTCP_TransportHeader) = record {
byte_count: uint8;
registers: uint16[byte_count/2] &length=byte_count;
} &let {
deliver: bool = $context.flow.deliver_ReadHoldingRegistersResponse(header, this);
} &byteorder=bigendian;
# REQUEST FC=4
type ReadInputRegistersRequest(header: ModbusTCP_TransportHeader) = record {
start_address: uint16;
quantity: uint16; # &check(quantity <= 125);
} &let {
deliver: bool = $context.flow.deliver_ReadInputRegistersRequest(header, this);
} &byteorder=bigendian;
# RESPONSE FC=4
type ReadInputRegistersResponse(header: ModbusTCP_TransportHeader) = record {
byte_count: uint8;
registers: uint16[byte_count/2] &length=byte_count;
} &let {
deliver: bool = $context.flow.deliver_ReadInputRegistersResponse(header, this);
} &byteorder=bigendian;
# REQUEST FC=5
type WriteSingleCoilRequest(header: ModbusTCP_TransportHeader) = record {
address: uint16;
value: uint16; # &check(value == 0x0000 || value == 0xFF00);
} &let {
deliver: bool = $context.flow.deliver_WriteSingleCoilRequest(header, this);
} &byteorder=bigendian;
# RESPONSE FC=5
type WriteSingleCoilResponse(header: ModbusTCP_TransportHeader) = record {
address: uint16;
value: uint16; # &check(value == 0x0000 || value == 0xFF00);
} &let {
deliver: bool = $context.flow.deliver_WriteSingleCoilResponse(header, this);
} &byteorder=bigendian;
# REQUEST FC=6
type WriteSingleRegisterRequest(header: ModbusTCP_TransportHeader) = record {
address: uint16;
value: uint16;
} &let {
deliver: bool = $context.flow.deliver_WriteSingleRegisterRequest(header, this);
} &byteorder=bigendian;
# RESPONSE FC=6
type WriteSingleRegisterResponse(header: ModbusTCP_TransportHeader) = record {
address: uint16;
value: uint16;
} &let {
deliver: bool = $context.flow.deliver_WriteSingleRegisterResponse(header, this);
} &byteorder=bigendian;
# REQUEST FC=15
type WriteMultipleCoilsRequest(header: ModbusTCP_TransportHeader) = record {
start_address: uint16;
quantity: uint16; # &check(quantity <= 0x07B0);
byte_count: uint8; # &check(byte_count == (quantity + 7)/8);
coils: bytestring &length=byte_count;
} &let {
deliver: bool = $context.flow.deliver_WriteMultipleCoilsRequest(header, this);
} &byteorder=bigendian;
# RESPONSE FC=15
type WriteMultipleCoilsResponse(header: ModbusTCP_TransportHeader) = record {
start_address: uint16;
quantity: uint16; # &check(quantity <= 0x07B0);
} &let {
deliver: bool = $context.flow.deliver_WriteMultipleCoilsResponse(header, this);
} &byteorder=bigendian;
# REQUEST FC=16
type WriteMultipleRegistersRequest(header: ModbusTCP_TransportHeader) = record {
start_address: uint16;
quantity: uint16;
byte_count: uint8;
# We specify registers buffer with quantity and byte_count so that the analyzer
# will choke if something doesn't match right (correct devices should make it right).
registers: uint16[quantity] &length=byte_count;
} &let {
deliver: bool = $context.flow.deliver_WriteMultipleRegistersRequest(header, this);
} &byteorder=bigendian;
# RESPONSE FC=16
type WriteMultipleRegistersResponse(header: ModbusTCP_TransportHeader) = record {
start_address: uint16;
quantity: uint16;
} &let {
deliver: bool = $context.flow.deliver_WriteMultipleRegistersResponse(header, this);
} &byteorder=bigendian;
# Support data structure for following message type.
type FileRecordRequest = record {
ref_type: uint8; # &check(ref_type == 6);
file_num: uint16; # &check(file_num > 0);
record_num: uint16; # &check(record_num <= 0x270F);
record_len: uint16;
} &byteorder=bigendian;
# REQUEST FC=20
type ReadFileRecordRequest(header: ModbusTCP_TransportHeader) = record {
byte_count: uint8; # &check(byte_count <= 0xF5);
references: FileRecordRequest[] &length=byte_count;
} &let {
deliver: bool = $context.flow.deliver_ReadFileRecordRequest(header, this);
} &byteorder=bigendian;
# Support data structure for the following message type.
type FileRecordResponse = record {
file_len: uint8; # &check(file_len >= 0x07 && file_len <= 0xF5);
ref_type: uint8; # &check(ref_type == 6);
record_data: uint16[file_len/2] &length=file_len;
} &byteorder=bigendian;
# RESPONSE FC=20
type ReadFileRecordResponse(header: ModbusTCP_TransportHeader) = record {
byte_count: uint8; # &check(byte_count >= 0x07 && byte_count <= 0xF5);
references: FileRecordResponse[] &length=byte_count;
} &let {
deliver: bool = $context.flow.deliver_ReadFileRecordResponse(header, this);
} &byteorder=bigendian;
# Support data structure for the two following message types.
type ReferenceWithData = record {
ref_type: uint8;
file_num: uint16;
record_num: uint16;
word_count: uint16;
register_value: uint16[word_count];
} &byteorder=bigendian;
# REQUEST FC=21
type WriteFileRecordRequest(header: ModbusTCP_TransportHeader) = record {
byte_count: uint8;
references: ReferenceWithData[] &length=byte_count;
} &let {
deliver: bool = $context.flow.deliver_WriteFileRecordRequest(header, this);
} &byteorder=bigendian;
# RESPONSE FC=21
type WriteFileRecordResponse(header: ModbusTCP_TransportHeader) = record {
byte_count: uint8;
references: ReferenceWithData[] &length=byte_count;
} &let {
deliver: bool = $context.flow.deliver_WriteFileRecordResponse(header, this);
} &byteorder=bigendian;
# REQUEST FC=22
type MaskWriteRegisterRequest(header: ModbusTCP_TransportHeader) = record {
address: uint16;
and_mask: uint16;
or_mask: uint16;
} &let {
deliver: bool = $context.flow.deliver_MaskWriteRegisterRequest(header, this);
} &byteorder=bigendian;
# RESPONSE FC=22
type MaskWriteRegisterResponse(header: ModbusTCP_TransportHeader) = record {
address: uint16;
and_mask: uint16;
or_mask: uint16;
} &let {
deliver: bool = $context.flow.deliver_MaskWriteRegisterResponse(header, this);
} &byteorder=bigendian;
# REQUEST FC=23
type ReadWriteMultipleRegistersRequest(header: ModbusTCP_TransportHeader) = record {
read_start_address: uint16;
read_quantity: uint16; # &check(read_quantity <= 125);
write_start_address: uint16;
write_quantity: uint16; # &check(write_quantity <= 100);
write_byte_count: uint8;
write_register_values: uint16[write_quantity] &length=write_byte_count;
} &let {
deliver: bool = $context.flow.deliver_ReadWriteMultipleRegistersRequest(header, this);
} &byteorder=bigendian;
# RESPONSE FC=23
type ReadWriteMultipleRegistersResponse(header: ModbusTCP_TransportHeader) = record {
byte_count: uint8;
registers: uint16[byte_count/2] &length=byte_count;
} &let {
deliver: bool = $context.flow.deliver_ReadWriteMultipleRegistersResponse(header, this);
} &byteorder=bigendian;
# REQUEST FC=24
type ReadFIFOQueueRequest(header: ModbusTCP_TransportHeader) = record {
start_address: uint16;
} &let{
deliver: bool = $context.flow.deliver_ReadFIFOQueueRequest(header, this);
} &byteorder=bigendian;
# RESPONSE FC=24
type ReadFIFOQueueResponse(header: ModbusTCP_TransportHeader) = record {
byte_count: uint16; # &check(byte_count <= 62);
fifo_count: uint16; # &check(fifo_count <= 31);
register_data: uint16[fifo_count] &length=fifo_count*2;
} &let {
deliver: bool = $context.flow.deliver_ReadFIFOQueueResponse(header, this);
} &byteorder=bigendian;