https://github.com/drasyl/netty-tun

netty channel communicating via TUN devices
https://github.com/drasyl/netty-tun

Last synced: 14 days ago
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netty channel communicating via TUN devices

• Host: GitHub
• URL: https://github.com/drasyl/netty-tun
• Owner: drasyl
• License: mit
• Created: 2021-12-30T23:22:55.000Z (almost 3 years ago)
• Default Branch: master
• Last Pushed: 2024-04-16T20:27:39.000Z (7 months ago)
• Last Synced: 2024-04-17T23:55:05.328Z (7 months ago)
• Language: Java
• Homepage:
• Size: 931 KB
• Stars: 9
• Watchers: 2
• Forks: 0
• Open Issues: 4
• Metadata Files:
  • Readme: README.md
  • License: LICENSE
  • Citation: CITATION.cff

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README

        
# netty-tun [![MIT License](https://img.shields.io/badge/license-MIT-blue)](https://opensource.org/licenses/MIT) [![Maven Central](https://img.shields.io/maven-central/v/org.drasyl/netty-tun.svg)](https://mvnrepository.com/artifact/org.drasyl/netty-tun) [![Javadoc](https://javadoc.io/badge2/org.drasyl/netty-tun/javadoc.svg)](https://www.javadoc.io/doc/org.drasyl/netty-tun)

netty channel communicating via TUN devices (tested on macOS, Ubuntu/Linux, and Windows 10/11).

## How to use

```java

EventLoopGroup group = new DefaultEventLoopGroup(1);

try {

    final Bootstrap b = new Bootstrap()

        .group(group)

        .channel(TunChannel.class)

        .handler(...);

    final Channel ch = b.bind(new TunAddress()).sync().channel();

    // send/receive messages of type TunPacket...

    ch.closeFuture().sync();

}

finally {

    group.shutdownGracefully();

}

```

### IP Address/Netmask

You can now assign an IP address and netmask to the created network interface (you can query the

actual interface name by

calling [Channel#localAddress()](https://netty.io/4.1/api/io/netty/channel/Channel.html#localAddress--)):

```bash

# macOS

sudo /sbin/ifconfig utun0 add 10.10.10.10 10.10.10.10

sudo /sbin/ifconfig utun0 up

sudo /sbin/route add -net 10.10.10.0/24 -iface utun0

# Linux

sudo /sbin/ip addr add 10.10.10.10/24 dev utun0

sudo /sbin/ip link set dev utun0 up

```

```powershell

# Windows

$InterfaceIndex = Get-NetAdapter -Name utun0 | select ifIndex -expandproperty ifIndex

New-NetIPAddress -InterfaceIndex $InterfaceIndex -IPAddress 10.10.10.10 -PrefixLength 24

# to allow peers access local services, you may mark the tun network as "private"

Set-NetConnectionProfile -InterfaceIndex $InterfaceIndex -NetworkCategory "Private"

```

## MTU

The MTU size of the created network interface is by default 1500 on macOS/Linux and 65535 on Windows.

On macOS/Linux is can be adjusted by passing the channel option [`TunChannelOption.TUN_MTU`](https://github.com/drasyl/netty-tun/blob/master/src/main/java/org/drasyl/channel/tun/TunChannelOption.java) to the [`Bootstrap`](https://netty.io/4.1/api/io/netty/bootstrap/Bootstrap.html) object.

On Windows you have to use the following command:

```powershell

netsh interface ipv4 set subinterface tun0 mtu=1234 store=active

```