tun_close is not killing sessions gracefully

[mary-dcouto]

When we call tun_close inside the scm_service_stop() function, the ziti_loop thread is crashing. It looks like it is not killing the sessions gracefully

[scareything]

Just to be clear, tun_close should not be responsible for closing sessions of any kind. It should only need to know about closing/freeing resources needed for the tun device.

I think the resolution of this issue will involve arranging the shutdown sequence of ziti-edge-tunnel to ensure that any dependencies on the tun device (e.g. active sessions) are closed before tun_close is called.