This fixed the following dependency loop that could occur when the
system was booting up:
1. NetworkManager configures a network interface and fires off the clatd
dispatcher script.
2. The dispatcher scripts tries to restart `clatd.service`.
3. However, `clatd.service` cannot be (re)started at this point because
its dependency `network-online.target` has not yet been reached.
4. Therefore, the `systemctl restart clatd.service` command in the
dispatcher script blocks, waiting for `network-online.target` to be
reached.
5. But that won't happen until the dispatcher scripts finishes...
Adding `--no-block` allows the dispatcher script to finish immediately
without waiting for the restart to complete (instead, systemd will do it
in the background once `network-online.target` has been reached).
Furthermore, since `clatd.service` may end up being restarted several
times during a boot process (especially on a system with many network
interfaces handled by NetworkManager), it is also at risk of
inadvertently triggering the restart rate-limiting feature in systemd,
so disable that while we're at it.
Closes#22. Thanks to @patrakov for the report!
Don't assume that utilities such as systemctl or initctl is found in a certain
specific path. Instead look for them in $PATH. This applies to both the
Makefile and the NetworkManager dispatcher script.
Resolves#11.
Newer NetworkManager versions will run the dispatcher scripts when new
unknown interfaces show up, including 'clat'. That will cause a clatd
restart right after startup, and we'll never get to fully initialise. So
ensure the dispatcher script does nothing if the device in question is
our own 'clat' to prevent this.
