Kermit

C#/.NET 10 class libraries that implement a Kermit-style serial file transfer stack for Windows and Linux.

Projects

KermitCommon

Shared protocol and transport layer.

Includes:

• Kermit packet models
• protocol constants and negotiation options
• packet encoding/decoding
• block check support
• serial transport abstraction
• shared session base class
• common events and event args
• shared NLog logging setup

KermitClient

Client-side transfer library.

Includes:

• upload files to a remote server
• request files from a remote server
• list remote folders with ls
• get remote working directory with pwd
• change remote directory with cd
• remove remote files and directories with rm
• create remote directories with mkdir
• progress events
• per-command events for packet activity

KermitServer

Server-side transfer library.

Includes:

• receive files from a client
• send files to a client
• handle get <file> generic command
• handle ls [folder] generic command
• handle pwd generic command
• handle cd <path> generic command
• handle rm <path> generic command
• handle mkdir <path> generic command
• handle delete <file> remote command
• progress events
• per-command events for packet activity

Target framework

• .NET 10 (net10.0)

Supported platforms

• Windows
• Linux

The transport uses System.IO.Ports, so matching serial device names must be used on each OS.

Examples:

• Windows: COM1, COM2, COM3
• Linux: /dev/ttyS0, /dev/ttyUSB0, /dev/ttyACM0

Features

• serial port transport
• asynchronous packet processing
• full-duplex session loop
• shared protocol base for client and server
• typed events for major Kermit commands
• shared logging with NLog
• file upload and download flows

Current protocol coverage

Implemented core packet flow:

• SEND-INIT
• FILE
• ATTR
• DATA
• EOF
• BREAK
• ACK
• NAK
• ERROR
• generic command packets
• remote command packets

Supported generic commands currently include:

• get <file>
• ls
• ls <folder>
• pwd
• cd <path>
• cd ..
• cd /
• rm <path>
• mkdir <path>

Not yet implemented

This repository currently provides a strong protocol foundation, but not every advanced Kermit feature is present yet.

Examples of future enhancements:

• long packets
• sliding windows larger than 1
• repeat-count compression
• fuller remote command set
• stricter interoperability with historical Kermit variants

Logging

KermitCommon configures NLog if no configuration already exists.

Client and server libraries reuse the same logging setup through the common project.

Build

From the workspace root:

dotnet build Kermit.slnx

Usage guides

See:

• clientused.md
• serverused.md

Remote folder listing example

var entries = await client.ListRemoteDirectoryAsync(".");

foreach (var entry in entries)
{
    Console.WriteLine($"{(entry.IsDirectory ? "<DIR>" : "FILE ")} {entry.Name} {entry.Size}");
}

Remote working directory example

var remotePath = await client.GetRemoteWorkingDirectoryAsync();
Console.WriteLine(remotePath);

Example client setup

using KermitClient;
using KermitCommon;

var transport = new SerialPortTransport("COM2", 115200);
var client = new KermitClientSession(
    transport,
    new KermitClientOptions
    {
        DownloadDirectory = Path.Combine(Environment.CurrentDirectory, "downloads")
    });

await client.OpenAsync();
await client.SendFileAsync(@"C:\temp\sample.txt");
await client.CloseAsync();
await client.DisposeAsync();

Example server setup

using KermitCommon;
using KermitServer;

var transport = new SerialPortTransport("COM1", 115200);
var server = new KermitServerSession(
    transport,
    new KermitServerOptions
    {
        RootDirectory = Path.Combine(Environment.CurrentDirectory, "storage")
    });

await server.OpenAsync();

Repository structure

• KermitCommon/
• KermitClient/
• KermitServer/
• clientused.md
• serverused.md

Status

The solution builds successfully and is ready for further protocol expansion, testing, and integration into applications that need serial Kermit transfers.