vpnkit

README

VPN-friendly networking devices for HyperKit

Binary artefacts are built by CI:

• MacOS
• Windows

VPNKit is a set of tools and services for helping HyperKit VMs interoperate with host VPN configurations.

Building on Unix

First install wget, opam using your package manager of choice.

Build all the dependencies and the program itself with:

cd [path to vpnkit source]
opam remote add vpnkit ./repo/darwin
opam install --deps-only vpnkit
make

When the build succeeds the vpnkit binary should be available in the current path.

Running with hyperkit

First ask vpnkit to listen for ethernet connections on a local Unix domain socket:

vpnkit --ethernet /tmp/ethernet --debug

Next ask com.docker.hyperkit to connect a NIC to this socket by adding a command-line option like -s 2:0,virtio-vpnkit,path=/tmp/ethernet. Note: you may need to change the slot 2:0 to a free slot in your VM configuration.

Why is this needed?

Running a VM usually involves modifying the network configuration on the host, for example by activating Ethernet bridges, new routing table entries, DNS and firewall/NAT configurations. Activating a VPN involves modifying the same routing tables, DNS and firewall/NAT configurations and therefore there can be a clash -- this often results in the network connection to the VM being disconnected.

VPNKit, part of HyperKit attempts to work nicely with VPN software by intercepting the VM traffic at the Ethernet level, parsing and understanding protocols like NTP, DNS, UDP, TCP and doing the "right thing" with respect to the host's VPN configuration.

VPNKit operates by reconstructing Ethernet traffic from the VM and translating it into the relevant socket API calls on OSX or Windows. This allows the host application to generate traffic without requiring low-level Ethernet bridging support.

Design

• Using vpnkit as a default gateway: describes the flow of ethernet traffic to/from the VM
• Port forwarding: describes how ports are forwarded from the host into the VM
• Experimental transparent HTTP proxy: describes the experimental support for transparent HTTP(S) proxying

Licensing

VPNKit is licensed under the Apache License, Version 2.0. See LICENSE for the full license text.

Contributions are welcome under the terms of this license. You may wish to browse the weekly reports to read about overall activity in the repository.