Packet.Core 0.20.0

Packet.Core

Shared primitive types for the Packet.NET amateur-radio stack.

Packet.Core holds the small, dependency-free building blocks the rest of the stack is built on: callsigns, AX.25 address slots, the FCS CRC, and the strict-vs-pragmatic parse options. It's the foundation package that Packet.Ax25, Packet.Kiss, Packet.Aprs and downstream applications depend on. Part of Packet.NET, a .NET amateur-radio / AX.25 packet stack.

Install

dotnet add package Packet.Core

Quick start

using Packet.Core;

// Parse a human-typed callsign ("BASE" or "BASE-SSID"), strictly.
var call = Callsign.Parse("Q0PDN-7");
Console.WriteLine(call.Base);      // "Q0PDN"
Console.WriteLine(call.Ssid);      // 7
Console.WriteLine(call.ToString()); // "Q0PDN-7"

// Encode one 7-octet AX.25 address slot, then read it back.
var addr = new Ax25Address(call, CrhBit: true, ExtensionBit: false);
Span<byte> slot = stackalloc byte[Ax25Address.EncodedLength]; // 7
addr.Write(slot);

var decoded = Ax25Address.Read(slot);       // lenient by default
Console.WriteLine(decoded == addr);          // True (round-trips)

// Strict spec parsing: reject pragmatic accommodations (e.g. all-space slots).
var strict = Ax25Address.Read(slot, Ax25ParseOptions.Strict);

// AX.25 frame check sequence (CRC-16/X-25).
ushort fcs = Crc16Ccitt.Compute("123456789"u8); // 0x906E

Callsign.Parse / TryParse stay strict (≥1 char, A–Z / 0–9, SSID 0–15) because they're for user-typed input. The wire-parse path (Ax25Address.Read) is lenient by default — it accepts real-world quirks like all-space address slots — and you opt into strictness via Ax25ParseOptions.Strict.

Key types

• Callsign — a base callsign + SSID (0–15) value type, with strict Parse/TryParse over text.
• Ax25Address — one 7-octet AX.25 header address slot; Read/Write between the value and its wire form, with the C/H and extension bits.
• Ax25ParseOptions — named, individually-toggleable pragmatic-parse flags with Strict / Lenient and peer presets (Bpq, Xrouter, Direwolf).
• Crc16Ccitt — the AX.25 frame check sequence (CRC-16/X-25, polynomial 0x1021).

See also

• Source & issues
• Packet.Ax25 — the AX.25 framing and session layer built on these primitives.
• Packet.Kiss — KISS TNC framing.

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