tsnet users can now provide a tun.Device, including any custom
implementation that conforms to the interface.
netstack has a new option CheckLocalTransportEndpoints that when used
alongside a TUN enables netstack listens and dials to correctly capture
traffic associated with those sockets. tsnet with a TUN sets this
option, while all other builds leave this at false to preserve existing
performance.
Updates #18423
Signed-off-by: James Tucker <james@tailscale.com>
James TuckerandJames Tucker
63d563e734