Struct ModbusLayer 

pub struct ModbusLayer {
    pub index: LayerIndex,
    pub frame_type: ModbusFrameType,
}

Modbus layer – a zero-copy view into a packet buffer.

By default assumes Modbus/TCP (MBAP) framing since that is what appears on the wire over TCP port 502.

Fields

index: LayerIndex

frame_type: ModbusFrameType

Implementations

impl ModbusLayer

pub fn new(index: LayerIndex) -> Self

Create a new Modbus layer from a layer index (defaults to TCP framing).

pub fn with_frame_type(index: LayerIndex, frame_type: ModbusFrameType) -> Self

Create a Modbus layer with explicit frame type.

pub fn trans_id(&self, buf: &[u8]) -> Result<u16, FieldError>

Get the Transaction ID (MBAP bytes 0-1).

pub fn proto_id(&self, buf: &[u8]) -> Result<u16, FieldError>

Get the Protocol ID (MBAP bytes 2-3; should be 0x0000).

pub fn length(&self, buf: &[u8]) -> Result<u16, FieldError>

Get the Length field (MBAP bytes 4-5).

pub fn unit_id(&self, buf: &[u8]) -> Result<u8, FieldError>

Get the Unit ID (MBAP byte 6).

pub fn func_code(&self, buf: &[u8]) -> Result<u8, FieldError>

Get the Function Code (MBAP byte 7).

pub fn is_error(&self, buf: &[u8]) -> bool

Check if this is an exception response (function code has bit 7 set).

pub fn except_code(&self, buf: &[u8]) -> Result<u8, FieldError>

Get the exception code (byte 8, only valid for error responses).

pub fn start_addr(&self, buf: &[u8]) -> Result<u16, FieldError>

Get the Start Address (bytes 8-9 for request PDUs like 0x01-0x06).

pub fn quantity(&self, buf: &[u8]) -> Result<u16, FieldError>

Get the Quantity field (bytes 10-11 for request PDUs like 0x01-0x04).

pub fn byte_count(&self, buf: &[u8]) -> Result<u8, FieldError>

Get the Byte Count field (byte 8 for response PDUs like 0x01-0x04).

pub fn output_value(&self, buf: &[u8]) -> Result<u16, FieldError>

Get the Output Value for Write Single Coil/Register (bytes 10-11).

pub fn register_val(&self, buf: &[u8]) -> Result<u16, FieldError>

Get the Register Value for Write Single Register (bytes 10-11).

pub fn sub_func(&self, buf: &[u8]) -> Result<u16, FieldError>

Get the Sub-function code for Diagnostics (0x08) (bytes 8-9).

pub fn ref_addr(&self, buf: &[u8]) -> Result<u16, FieldError>

Get the Reference Address for Mask Write Register (0x16) (bytes 8-9).

pub fn and_mask(&self, buf: &[u8]) -> Result<u16, FieldError>

Get the AND mask for Mask Write Register (0x16) (bytes 10-11).

pub fn or_mask(&self, buf: &[u8]) -> Result<u16, FieldError>

Get the OR mask for Mask Write Register (0x16) (bytes 12-13).

pub fn data(&self, buf: &[u8]) -> Result<Vec<u8>, FieldError>

Get the raw data bytes after the function code (bytes 8..end).

pub fn set_trans_id(&self, buf: &mut [u8], value: u16) -> Result<(), FieldError>

Set the Transaction ID.

pub fn set_unit_id(&self, buf: &mut [u8], value: u8) -> Result<(), FieldError>

Set the Unit ID.

pub fn set_func_code(&self, buf: &mut [u8], value: u8) -> Result<(), FieldError>

Set the Function Code.

pub fn set_start_addr( &self, buf: &mut [u8], value: u16, ) -> Result<(), FieldError>

Set the Start Address (bytes 8-9).

pub fn set_quantity(&self, buf: &mut [u8], value: u16) -> Result<(), FieldError>

Set the Quantity (bytes 10-11).

pub fn summary(&self, buf: &[u8]) -> String

Generate a one-line summary of this Modbus layer.

pub fn field_names() -> &'static [&'static str]

Get the field names for this layer.

pub fn get_field( &self, buf: &[u8], name: &str, ) -> Option<Result<FieldValue, FieldError>>

Get a field value by name.

pub fn set_field( &self, buf: &mut [u8], name: &str, value: FieldValue, ) -> Option<Result<(), FieldError>>

Set a field value by name.

Trait Implementations

impl Clone for ModbusLayer

fn clone(&self) -> ModbusLayer

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ModbusLayer

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Layer for ModbusLayer

fn kind(&self) -> LayerKind

Get the kind of this layer

fn summary(&self, data: &[u8]) -> String

Get a human-readable summary of this layer

fn header_len(&self, data: &[u8]) -> usize

Get the header length for this layer

fn field_names(&self) -> &'static [&'static str]

Get the list of field names for this layer

fn hashret(&self, _data: &[u8]) -> Vec<u8>

Compute a hash for packet matching.

fn answers(&self, _data: &[u8], _other: &Self, _other_data: &[u8]) -> bool

Check if this packet answers another packet.

fn extract_padding<'a>(&self, data: &'a [u8]) -> (&'a [u8], &'a [u8])

Extract padding from the packet.