Send packet example

This is a simple example project that uses JPAN to send a packet to the SCION packet inspector.

To try out the example please download the stand-alone jar file through one of these options:

• download link to release section
• wget https://github.com/netsec-ethz/scion-java-packet-example/releases/download/v0.5.0/packet-example-0.5.0.jar

Then execute it (requires Java 1.8 or later):

java -jar packet-example-0.5.0.jar

You can also send a custom message string with

java -jar packet-example-0.5.0.jar "A better message"

The message can be seen in the hex dump at the bottom of the SCION packet inspector page.

Other examples

The project contains other examples, but they do not come with an executable jar file:

• Use explicit path example
• Custom path policy example
• Ping-pong examples
  • DatagramChannel client
  • DatagramChannel server
  • DatagramSocket client
  • DatagramSocket server

Building your own executable jar

You can build your own executable jar file with

mvn clean package -Pcreate-executable-example

This creates a file packet-example-0.5.1-SNAPSHOT.jar in target/. (Note, the scion-... jar file is not executable)

Troubleshooting

No DNS search domain found. Please check your /etc/resolv.conf or similar.

This happens, for example, on Windows when using a VPN. There are several solutions to this (aside from reconfiguring your system).

Solution #1: Provide search domain

This is useful if you have access to a search domain with a NAPTR record of the discovery server. You can execute the jar with the following property (on example of a search domain is ethz.ch. but it obviously works only when you are in that very domain):

java -Dorg.scion.dnsSearchDomains=<search domain> -jar packet-example-<version>.jar

Solution #2: Provide a discovery server

You can directly set the IP:port of the discovery server:

java -Dorg.scion.bootstrap.host=<IP of bootstrap server:8041> -jar packet-example-<version>.jar

Solution #3: Provide a topology file

If you have a topology file, you can do the following:

java -Dorg.scion.bootstrap.topoFile=<yourTopologyFile.json> -jar packet-example-<version>.jar