turncat is a STUN/TURN client to open a connection through a TURN server to an arbitrary remote
address/port. The main use is to open a local tunnel endpoint to any service running inside a
Kubernetes cluster via STUNner. This is very similar in functionality to kubectl proxy, but it
uses STUN/TURN to enter the cluster.
Getting Started
Installation
As simple as it gets:
cd stunner
go build -o turncat cmd/turncat/main.go
Usage
Listen to client connections on the UDP listener 127.0.0.1:5000 and tunnel the received packets
through the TURN server located at 192.0.2.1:3478 to the UDP server located at
192.0.2.2:53. Use the longterm STUN/TURN credential mechanism to authenticate with the TURN
server and set the user/passwd to test/test:
./turncat --log=all:INFO,turncat:DEBUG udp://127.0.0.1:5000 turn://test:test@192.0.2.1:3478 udp://192.0.2.2:53
TLS/DTLS should also work fine; note that --insecure allows turncat to accept self-signed TLS
certificates and --verbose is equivalent to setting all turncat loggers to DEBUG mode (-l all:DEBUG).
./turncat --verbose --insecure udp://127.0.0.1:5000 turn://test:test@192.0.2.1:3478?transport=tls udp://192.0.2.2:53
Alternatively, specify the special TURN server URI k8s://stunner/stunnerd-config:udp-listener to
let turncat parse the running STUNner configuration from the active Kubernetes cluster. The URI
directs turncat to read the STUNner config from the ConfigMap named stunnerd-config in the
stunner namespace, and connect to the STUNner listener named udp-listener. The CLI flag -
instructs turncat to listen on the standard input: anything you type in the terminal will be sent
via STUNner to the peer udp://10.0.0.1:9001 (after you press Enter). The CLI flag -v will
enable verbose logging.
./turncat -v - k8s://stunner/stunnerd-config:udp-listener udp://10.0.0.1:9001
License
Copyright 2021-2023 by its authors. Some rights reserved. See AUTHORS.
MIT License - see LICENSE for full text.
Acknowledgments
Initial code adopted from pion/stun and
pion/turn.