valence/packet_inspector

What's This?

The packet inspector is a very simple Minecraft proxy for viewing the contents of packets as they are sent/received. It uses Valence's protocol facilities to print packet contents. This was made for three purposes:

• Check that packets between Valence and client are matching your expectations.
• Check that packets between vanilla server and client are parsed correctly by Valence.
• Understand how the protocol works between the vanilla server and client.

Usage

First, start a server

cargo r -r --example conway

In a separate terminal, start the packet inspector.

cargo r -r -p packet_inspector -- 127.0.0.1:25566 127.0.0.1:25565

The client must connect to localhost:25566. You should see the packets in stdout.

The -i and -e flags accept a regex to filter packets according to their name. The -i regex includes matching packets while the -e regex excludes matching packets.

For instance, if you only want to print the packets Foo, Bar, and Baz, you can use a regex such as ^(Foo|Bar|Baz)$ with the -i flag.

cargo r -r -p packet_inspector -- 127.0.0.1:25566 127.0.0.1:25565 '^(Foo|Bar|Baz)$'

Packets are printed to stdout while errors are printed to stderr. If you only want to see errors in your terminal, direct stdout elsewhere.

cargo r -r -p packet_inspector -- 127.0.0.1:25566 127.0.0.1:25565 > log.txt

Quick start with Vanilla Server via Docker

Start the server

docker run -e EULA=TRUE -e ONLINE_MODE=false -d -p 25565:25565 --name mc itzg/minecraft-server

View server logs

docker logs -f mc

Server Rcon

docker exec -i mc rcon-cli

In a separate terminal, start the packet inspector.

cargo r -r -p packet_inspector -- 127.0.0.1:25566 127.0.0.1:25565

Open Minecraft and connect to localhost:25566.

Clean up

docker stop mc
docker rm mc