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clatd/scripts/clatd.networkmanager
Tore Anderson a416278570 Make NM/systemd integration more robust
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!
2023-03-05 10:58:29 +01:00

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#!/bin/sh
#
# clatd dispatcher script for NetworkManager
#
# Install it to: /etc/NetworkManager/dispatcher.d/50-clatd
#
# Written by Tore Anderson <tore@fud.no>
#
# Newer NetworkManager versions will run the dispatcher scripts once
# a new unmanaged interface shows up, including the 'clat' interface
# created by clatd/TAYGA. So if we're being called due to our own
# interface showing up, do nothing, otherwise we will end up
# committing suicide from the restarts below
[ "$DEVICE_IFACE" = "clat" ] && exit 0
# We're only acting on interface "up" or "down" events. NM will run the
# dispatcher scripts for other events we're not interested in, like the
# hostname being set or a DHCP lease being renewed. Ignore those.
[ "$2" != "up" ] && [ "$2" != "down" ] && exit 0
# We simply restart clatd in all situations, as no matter if an interface
# goes up or down, it may mean that the PLAT device changes, it may mean
# native IPv4 appearing or disappearing, or it may mean that DNS64 became
# available or unavailable...it's far easier to simply restart always and
# start from scratch than to figure out if a restart is truly necessary
# systemd-based distros
if which systemctl &> /dev/null; then
systemctl --no-block restart clatd.service
fi
# upstart-based distros
if test -x /sbin/initctl; then
/sbin/initctl restart clatd
fi