Thomas Eizinger 6c842de83c refactor(connlib): don't re-initialise Tun on config updates (#5392) ...

Currently, connlib re-initialises the TUN device on Linux every time its
configuration gets updated such as when roaming from one network to
another. This is unnecessary. Instead, we can adopt the same approach as
already used on MacOS, iOS and Windows and only initialise it if it
doesn't exist yet.

Doing so surfaces an interesting bug. Currently, attempting to
re-initialise the TUN device fails with a warning:

> connlib_client_shared::eventloop: Failed to set interface on tunnel:
Resource busy (os error 16)

See
https://github.com/firezone/firezone/actions/runs/9656570163/job/26634409346#step:7:103
for an example. As a consequence, we never actually trigger the
`on_set_interface_config` callback and thus never actually set the new
IPs on the TUN device.

Now that we _are_ calling this callback, we execute
`TunDeviceManager::set_ips` which first clears all IPs from the device
and then attaches the new ones. A consequence of this is that the Linux
kernel will clear all routes associated with the device. This clashes
with an optimisation we have in `TunDeviceManager` where we remember the
previously set routes and don't set new ones if they are the same.

This `HashSet` needs to be cleared upon setting new IPs in order to
actually set the new routes correctly afterwards. Without that, we stop
receiving traffic on the TUN device.

2024-06-25 22:30:31 +00:00

..

src

refactor(connlib): don't re-initialise Tun on config updates (#5392)

2024-06-25 22:30:31 +00:00

Cargo.toml

feat(gateway): NAT & mangling for DNS resources (#5354)

2024-06-19 01:15:27 +00:00