Struct L2tpBuilder 

pub struct L2tpBuilder { /* private fields */ }

Builder for L2TPv2 packets.

The builder encodes the header flags and optional fields according to RFC 2661. Fields:

• T bit (message type): cleared for data, set for control
• L bit: when set a 2-byte Length field appears after the flags word
• S bit: when set Ns and Nr (2 bytes each) appear after Session ID
• O bit: when set Offset Size + Offset Pad appear after Nr (or Session ID)
• Ver nibble: always 2 for L2TPv2

Implementations

impl L2tpBuilder

pub fn new() -> Self

Create a new L2TP data message builder with minimal defaults. Produces a 6-byte header: \x00\x02\x00\x00\x00\x00 (ver=2, tid=0, sid=0).

pub fn control(self) -> Self

Set the T bit — makes this a control message.

pub fn data(self) -> Self

Set the T bit to 0 — data message (default).

pub fn with_length(self) -> Self

Set the L (length) bit so a Length field will be included in the header.

pub fn with_sequence(self) -> Self

Set the S (sequence) bit so Ns and Nr will be included.

pub fn with_offset(self) -> Self

Set the O (offset) bit so Offset Size + Offset Pad will be included.

pub fn priority(self) -> Self

Set the P (priority) bit for data messages.

pub fn tunnel_id(self, id: u16) -> Self

Set the Tunnel ID.

pub fn session_id(self, id: u16) -> Self

Set the Session ID.

pub fn ns(self, ns: u16) -> Self

Set the Ns (send sequence number) field. Automatically enables the S bit.

pub fn nr(self, nr: u16) -> Self

Set the Nr (receive sequence number) field. Automatically enables the S bit.

pub fn offset_size(self, size: u16) -> Self

Set the Offset Size field. Automatically enables the O bit.

pub fn payload<T: Into<Vec<u8>>>(self, data: T) -> Self

Set the payload (data after the L2TP header).

pub fn control_length() -> Self

Create a control message with the Length bit set (matching Scapy’s L2TP(hdr="control+length") default).

pub fn header_size(&self) -> usize

Compute the header length in bytes.

pub fn packet_size(&self) -> usize

Compute the total packet size (header + payload).

pub fn build(&self) -> Vec<u8>

Serialize the L2TP header (and payload if any) into bytes.

pub fn build_into(&self, buf: &mut Vec<u8>)

Serialize into an existing buffer (must be at least packet_size() bytes).

Trait Implementations

impl Clone for L2tpBuilder

fn clone(&self) -> L2tpBuilder

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for L2tpBuilder

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

Formats the value using the given formatter.

impl Default for L2tpBuilder

fn default() -> L2tpBuilder

Returns the “default value” for a type.

impl IntoLayerStackEntry for L2tpBuilder

fn into_layer_stack_entry(self) -> LayerStackEntry