vpncloud/WINDOWS.md

VpnCloud for Windows

Toolchain

Setup toolchain: rustup target add x86_64-pc-windows-gnu rustup toolchain install stable-x86_64-pc-windows-gnu apt-get install mingw64

Cross-compile with: cargo build --target x86_64-pc-windows-gnu

Problems

Running VpnCloud

Problem:

• Library "daemonize" does not compile
  • Windows uses "Services" instead of daemonized processes
• Library "privdrop" does not compile
  • Is dropping privileges in Windows services even a thing?
• Library "signal" does not compile
  • Windows services work differently, no Ctrl-C handling needed
• Normal Windows programs can't stay active when the user logs out

Potential solution:

• Wrap VpnCloud as Windows service
  • https://github.com/mullvad/windows-service-rs
• Do not support dropping privileges or daemonizing under Windows
• Only use Ctrl-C handling under Linux

Polling solution

Problem:

• Epoll is Linux only
• RawFd is Unix only

Potential solution:

Use multi-threading to remove the need to wait on multiple events at the same time:

• One thread waits on the device and sends to the socket
• One thread waits on the socket and sends to the device and handles the control traffic

Problems to solve:

• Synchronization is slow
  • Do not use locking in hot code, cache shared data locally and synchronize periodically
• Find out if this is faster/slower than current solution

Tun/Tap devices

Problem:

Tun/Tap works completely different on Windows

• Drivers need to be signed by Microsoft, complicated process

Potential solution:

Use existing Tun & Tap drivers:

• (Old) TapWindows from OpenVPN project

  • https://community.openvpn.net/openvpn/wiki/GettingTapWindows
  • https://github.com/Tazdevil971/tap-windows

• (New) WinTun from Wireguard

  • https://www.wintun.net/

Configuration

Problem:

• Windows users are not used to write config files and execute commands
• Windows setup is more complicated than in Linux (install Drivers, register Services, etc.)

Potential solution:

• Create configuration UI