watchcat: use logical network to fix restart_interface

[danielfdickinson]

📦 Package Details

Maintainer: @roger-

Description:

As reported in #23410 Network interface reset doesn't work as expected
on a Wireguard VPN interface and in #27927 lt2p interface won't reboot,
and mentioned in #27248, the current implementation of the option to
restart an interface when connectivity check fails for some period does
not result in an interface restart for all interface.

Notably 'virtual' interfaces such as Wireguard and L2TP do not restart.

The solution that works is to use ifup <interface> instead of only
changing the link status.

This commit is based on the one in #27248 by @rondoval, who unfortunately
has not updated the commit message as requested for half a year.

and an update:

Watchcat was failing to restart layer-3 interfaces when in mode
'restart_iface'. The previously attempted fix made the situation
worse in that it resulted in layer 2 interfaces also failing to
start.

This was because we are passed the interface name (e.g. eth0,
l2p0, or br-lan), but ifup needs the logical network (e.g. 'lan'
which corresponds to the network device).

Update to use find_config from /lib/network/config.sh to find the
logical network from the interface name, and use ifup on the
logical network to restart the underlying interface(s) associated
with the logical network.

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🧪 Run Testing Details

• OpenWrt Version: OpenWrt 25.12-SNAPSHOT r32848-1f535037b1
• OpenWrt Target/Subtarget: bcm27xx/bcm2712
• OpenWrt Device: Raspberry Pi 5 Model B Rev 1.0

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✅ Formalities

• I have reviewed the CONTRIBUTING.md file for detailed contributing guidelines.

[danielfdickinson]

@hnyman @BKPepe ping?

[danielfdickinson]

@feckert @hnyman @dibdot ping?

[hnyman]

It is just cherry-pick, right?
If you believe the changes to be right also in 25.12 (that doesn't yet deviate much from main/master), just merge it. (I am not quite sure what we should be reviewing there)

[danielfdickinson]

@hnyman I don't have merge access - just a contributor. I was mistaken because of a UI thing with GitHub, when I thought I did have commit access when I returned from a long hiatus. If the team is willing to have me on board, I would be happy to accept commit privileges (and apply them responsibly).

[hnyman]

Ok, I merged it.
(I remembered your earlier comment about merge right still being there, so I wondered)

[danielfdickinson]

Thank you. (And sorry for the confusion).