Packet.Kiss 0.21.0

Packet.Kiss

KISS framing, ACKMODE, multi-drop ports, and a TCP transport for AX.25.

Encodes and decodes KISS frames (the SLIP-style framing that TNCs and software modems speak), handles the G8BPQ ACKMODE extension and multi-drop port nibble, and ships KissTcpClient for talking KISS-over-TCP to a TNC or node. Decoded KISS-Data payloads surface as typed Ax25Frame events. Part of Packet.NET, a .NET amateur-radio / AX.25 packet stack.

Install

dotnet add package Packet.Kiss

Quick start

Encode an AX.25 frame to KISS wire bytes, and decode wire bytes back into frames:

using Packet.Kiss;

// Encode: FEND | (port<<4)|cmd | escaped-payload | FEND
byte[] wire = KissEncoder.Encode(port: 0, KissCommand.Data, ax25Bytes);

// Decode is stateful — push bytes as they arrive off the wire, pull frames out.
var decoder = new KissDecoder();
foreach (KissFrame frame in decoder.Push(wire))
{
    if (frame.Command == KissCommand.Data)
    {
        // frame.Payload is the AX.25 frame body (the TNC strips/inserts the FCS).
    }
}

Classify an inbound frame into a typed event (Data → AX.25, ACKMODE-Data, or Unknown):

KissInboundEvent evt = KissFrameClassifier.Classify(frame);
if (evt is Ax25FrameReceivedEvent ax25)
{
    // ax25.Ax25 is a parsed Packet.Ax25.Ax25Frame
}

Talk KISS over TCP to a TNC or node (e.g. a LinBPQ KISS-over-TCP listener):

await using var client = await KissTcpClient.ConnectAsync("127.0.0.1", 8001);

// Fire-and-forget a KISS-Data frame on port 0.
await client.SendFrameAsync(ax25Bytes);

// Or send in ACKMODE and await the TNC's TX-completion echo (timing included).
TxCompletion done = await client.SendAwaitingCompletionAsync(ax25Bytes);

// Stream inbound frames until the link closes.
await foreach (KissFrame frame in client.ReadFramesAsync())
{
    // ...
}

Key types

• KissEncoder / KissDecoder — encode AX.25 bytes to KISS wire bytes; statefully decode an incoming byte stream into KissFrames.
• KissFrame — one decoded frame: Port, Command, and raw Payload.
• KissCommand — KISS command codes (Data, TxDelay, Persistence, SetHardware, AckMode, …).
• KissFraming — the FEND/FESC/TFEND/TFESC framing constants plus the exit-KISS byte.
• KissTcpClient — KISS-over-TCP client implementing IAx25Transport; handles framing both directions, ACKMODE TX-completion, CSMA params, and half-open-link idle detection.
• KissFrameClassifier / KissInboundEvent — map a raw frame to a typed inbound event (Ax25FrameReceivedEvent, AckModeDataReceivedEvent, UnknownInboundEvent).
• KissAckMode — build/parse the G8BPQ ACKMODE extension (command 0x0C) with its 2-byte sequence tag.
• KissAx25Bridge — wire a KISS transport to a Packet.Ax25 connected-mode session adapter.

See also

• Source & issues
• Packet.Ax25 — the AX.25 frames + connected-mode sessions KISS carries.
• Packet.Kiss.NinoTnc — NinoTNC-specific KISS extensions (ACKMODE, SETHW, frame classification).
• Packet.Kiss.Serial — generic serial-port KISS modem.

MIT-licensed. Part of the Packet.NET stack.