Support for VZFileHandleNetworkDeviceAttachment & VZVmnetNetworkDeviceAttachment

[ctison]

It would be awesome to support:

• VZVmnetNetworkDeviceAttachment (macOS 26.0+)
• VZFileHandleNetworkDeviceAttachment (macOS 11.0+)

Supporting these would enable advanced network architectures, such as running a Linux routing VM with:

• A VZFileHandleNetworkDeviceAttachment, allowing packets to be read and written from the host, and routed through a VPN. This is especially useful when LAN connections are blocked (Docker Desktop uses a similar approach with VPNKit¹).
• A VZVmnetNetworkDeviceAttachment, which can also be mounted on other VMs to allow them to access the internet via the Linux routing VM.

This would enable cleaner solutions compared to existing workarounds:

• https://amodm.com/blog/2024/07/03/running-a-linux-router-on-macos

Note: #7380 did some work for VZVmnetNetworkDeviceAttachment.

Footnotes

1. https://docs.docker.com/desktop/features/networking/#vpn-passthrough ↩