IPv4 broken on macOS 10.14

[jeroenleenarts]

Summary

Somehow IPv4 traffic isn't working through the VPN on MacOS 10.14 (10.15 seems fine)

Steps to reproduce

Use TunnelKit in an app on MacOS.

What is the current bug behavior?

Connectivity with IPv4 fails on MacOS 10.14

What is the expected correct behavior?

It should work.

Relevant logs and/or screenshots

Please see: eduvpn/apple#191
Especially the pcap logging.

Possible fixes suggested remediation

This is our current workaround: johankool/tunnelkit@b72222f
( This workaround was included on our repo with this pull req:
eduvpn/apple#193 )

[efef]

Possibly the issue in the NETunnelInterface (TunnelKit library) and implementation of writePacket(:, completionHandler:) and writePackets(:, completionHandler:). Those methods seems to send the message with same protocol, setted in one place. Apple implementation, NEPacketTunnelFlow at the other side, implies that packets could be sent with different protocols.

[keeshux]

Somewhat introduced by ec29501

[jeroenleenarts]

@keeshux We might have a very simple fix for the IPv4/v6 issue on certain MacOS version.

@roop Has created a change on TunnelKit which we are now testing with EduVPN.

More details here: roop/tunnelkit@753927f

If it works out @roop has promised to issue a pull request. :)