vtunnel

README

vtunnel

Vtunnel is a virtual tunnel that leverages AF_VSOCK virtual sockets. Vtunnel runs two processes:

• host process that runs on the host machine
• peer process that runs inside a Hyper-V VM (e.g. WSL).

Host

The host process can be configured with an upstream HTTP/TCP server to forward the requests to. The tunnel accepts the incoming vsock requests over AF_VSOCK and for every request it creates a connection to the given upstream server to pipe the data forward.

Peer

The Peer process starts a TCP server inside the Hyper-V VM and listens for all the incoming requests; once a request is received it forwards it over the AF_SOCK to the host.

flowchart LR;
 subgraph Host["HOST"]
 UpstreamServer("Upstream HTTP/TCP Server")
 HostProcess("Vtunnel Host")
 UpstreamServer  <---> |over TCP| HostProcess
 end
 subgraph VM["WSL VM"]
 Peer("Vtunnel Peer")
 Client("client")
 Peer <--->  |over TCP| Client
 end
 HostProcess <---> |AF_VSOCK| Peer

E2E test

You can simply run the e2e test:

 go test -v .\test\e2e\connectivity_test.go

Manual Testing

• You will need to build the binaries for both Host and Peer processes:

 GOOS=windows go build
 GOOS=linux go build

• Creat a configuration file; below is an example of a config.yaml.
• The upstream-server-address can be in IP:Port format if upstream server is a TCP server; alternatively it can be be a named pipe server address, e.g. npipe:////./pipe/my-upstream-server. The npipe:// prefix is required. Note same configuration file can be used for both Peer and Host processes.

tunnel:
 - name: tcpTunnel
   handshake-port: 9090
   vsock-host-port: 8989
   peer-address: 127.0.0.1
   peer-port: 3030
   upstream-server-address: 127.0.0.1:4444
 - name: npipeTunnel
   handshake-port: 9091
   vsock-host-port: 8990
   peer-address: 127.0.0.1
   peer-port: 4040
   upstream-server-address: npipe:////./pipe/my-upstream-server

• Move the vtunnel executable to the Hyper-V VM and run the Peer process:

./vtunnel peer --config-path config.yaml

• Use netcat or a similar approach to run a HTTP/TCP server on the host machine:

python3 -m http.server 4444 --bind 127.0.0.1

• Run the host process on windows:

.\vtunnel.exe host --config-path config.yaml

• Using Curl or similar utilities send a request to the Peer TCP server inside the VM.

curl localhost:3030