porter

Tiny Java library that uses UPnP to map external WAN ports to internal LAN ports for both TCP and UDP on a supporting router.

Features

• Discover UPnP routers on the network.
• Discover external IP address.
• Map external TCP and UDP ports to internal ones.
• Automatically unmap on JVM shutdown.
• Requires Java 11 or above.
• Zero runtime dependencies.
• Graal Native Image compatible.

Installation

Available on Maven Central, so just add the following dependency to your project's pom.xml. Adjust for other build systems.

<dependency>
    <groupId>com.sshtools</groupId>
    <artifactId>porter</artifactId>
    <version>1.0.1</version>
</dependency> 

JPMS

If you are using JPMS, add com.sshtools.porter to your module-info.java.

Usage

Usage is very simple. A port mapping can be achieved with a single line of code.

UPnP.gateway().ifPresent(gw -> gw.map(80, Protocol.TCP));

Or to map different ports.

gw.map(8080, 80, Protocol.TCP);

Or to unmap.

gw.unmap(80, Protocol.TCP);

Or to test if mapped.

var mapped = gw.mapped(80, Protocol.TCP);
if(mapped) {
    System.out.println("Mapped!");
}
else {
    System.out.println("Not Mapped!");
}

For more control over the discovery process, instead of usage, UPnP.gateway(), use DiscoveryBuilder. You can use this to configure, monitor discovery, list all gateways and more.

try(var discovery = new UPnP.DiscoveryBuilder().
    withoutShutdownHooks().
    onGateway(gw -> {
        System.out.format("Gateway found %s%n", gw.ip());
    }).
    build()) {
    
    /* Not strictly needed, here from demonstrations purposes */
    discovery.awaitCompletion();
    
    /* gateways() will wait till complete */
    var count = discovery.gateways().size();
    System.out.format("Found %d gateways%n", count);
}