MQTTunnelNet: Tunnel TCP via MQTT broker

This library is a wrapper around libmqttunnel (https://github.com/Staatsgeheim/libmqttunnel)

Changelog

v1.0.6

• Fixed the library loading routine for Linux and OSX, netstandard2.0 and netstandard2.1 work properly now
• More fixed related to native library handling

v1.0.5

• Added configuration option to ignore SSL errors
• Fixed OSX x64 library, the build was corrupted in 1.0.4

v1.0.4

• Added Linux ARM64 support
• Added Linux x86 support

v1.0.3

• Changed the native library loading mechanism for cross platform compatibility
• Added MacOS x64 support
• Added MacOS ARM64 support
• Added Linux x64 support
• Added .NET 9 support

The library now supports:

Platforms:

• Windows x86
• Windows x64
• MacOS x64*
• MacOS ARM64*
• Linux x64

MacOS Notes*

Run xattr -r -d com.apple.quarantine libmqttunnel_x64.dylib or xattr -r -d com.apple.quarantine libmqttunnel_arm64.dylib to enable the libary to load unsigned

Runtimes:

• net45
• net451
• net452
• net46
• net461
• net462
• net463
• net47
• net471
• net472
• net48
• net481
• net5.0
• net6.0
• net7.0
• net8.0
• net9.0
• netstandard2.0
• netstandard2.1
• netcoreapp3.0
• netcoreapp3.1

v1.0.2

• Added 32 bits support
• Added support to load configs from memory instead of disk
• Added MQTTunnelLogLevel to give more control over the log level

enum MQTTunnelLogLevel : int { None = -1, DebugLevel = 0, InfoLevel = 1, WarnLevel = 2, ErrorLevel = 3, PanicLevel = 4, FatalLevel = 5 }

• Added support for more .NET versions

net45 net451 net452 net46 net461 net462 net463 net47 net471 net472 net48 net481 net5.0 net6.0 net7.0 net8.0 net9.0 netstandard2.0 netstandard2.1 netcoreapp3.0 netcoreapp3.1

How to use

Remote and local instances use the same Config file.

Create and start a server (remote)

var server = MQTTunnel.CreateServer("config.json"); server.StartAsync();

Create and connect a tunnel (local)

var tunnel = MQTTunnel.CreateTunnel("config.json", 9000, 8000) tunnel.StartAsync();

Create and connect multiple tunnels (local)

var tunnel1 = MQTTunnel.CreateTunnel("config.json", 9000, 8000) tunnel1.StartAsync(); var tunnel2 = MQTTunnel.CreateTunnel("config.json", 9001, 8001) tunnel2.StartAsync();

Using a config in memory

var configJsonData = @" { "host": "mqttbroker.example", "port": 8883, "ignoreSslErrors": false, "username", "", "password", "", "caCert": "root-CA.crt", "clientCert": "certificate.pem.crt", "privateKey": "private.pem.key", "control": "device/1/control" }";

Create and start a server using a config in memory (remote)

var server = MQTTunnel.CreateServerMem(configJsonData); server.StartAsync();

Create and connect a tunnel using a config in memory (local)

var tunnel = MQTTunnel.CreateTunnelMem(configJsonData, 9000, 8000) tunnel.StartAsync();

Create and connect multiple tunnels using a config in memory (local)

var tunnel1 = MQTTunnel.CreateTunnelMem(configJsonData, 9000, 8000) tunnel1.StartAsync(); var tunnel2 = MQTTunnel.CreateTunnelMem(configJsonData, 9001, 8001) tunnel2.StartAsync();

Config file

You can use client certs as well as username/password or both in the Config file.

{ "host": "mqttbroker.example", "port": 8883, "ignoreSslErrors": true, "username", "", "password", "", "caCert": "root-CA.crt", "clientCert": "certificate.pem.crt", "privateKey": "private.pem.key", "control": "device/1/control" }

Other options

• clientId: MQTT ClientID. If empty, random string is generated

Info

• control: Sets the MQTT topic that is used for this instance

Architecture

Example: Local port = 2022, Remote port = 22,

sequenceDiagram LocalTCP ->> LocalMQTTunnel: conn read from port 2022 LocalMQTTunnel ->> MQTTBroker: Publish to local port topic '/2022' MQTTBroker ->> RemoteMQTTunnel: Recieve from local port topic '/2022' RemoteMQTTunnel ->> RemoteTCP: conn write to port 22 RemoteTCP ->> RemoteMQTTunnel: conn read from port 22 RemoteMQTTunnel ->> MQTTBroker: Publish to local port topic '/22' MQTTBroker ->> LocalMQTTunnel: Recieve from local port topic '/22' LocalMQTTunnel ->> LocalTCP: conn write to port 2022

More internal architecture

sequenceDiagram participant Remote participant RemoteTCP participant RemoteTCPConnection participant RemoteMQTTunnel RemoteMQTTunnel ->> RemoteMQTTunnel: subscribe control topic LocalMQTTunnel ->> LocalMQTTunnel: make a Tunnel instance which includes local/remote port pair LocalMQTTunnel ->> LocalTCP: NewTCPConnection() LocalTCP ->> LocalTCP: start listening Local ->> LocalTCP: connect LocalTCP ->> LocalMQTTunnel: OpenTunnel() LocalMQTTunnel ->> RemoteMQTTunnel: Publish control packet RemoteMQTTunnel ->> RemoteTCPConnection: NewTCPConnection() RemoteTCPConnection ->> RemoteTCP: connect() RemoteTCP ->> Remote: connect()

License

• MIT