ddns-scripts doesn't autostart on boot, even when enabled in startup for those of us who use URL ip checker

[samwathegreat]

Package Name

ddns-scripts

Maintainer

feckert

OpenWrt Version

OpenWrt 23.05.5 (r24106-10cc5fcd00)

OpenWrt Target/Subtarget

x86

Steps to Reproduce

Set up a DDNS using URL (NOT network). Upon reboot, DDNS is never started!

#22698
This issue is referenced here ^

And the answer from @feckert was "The ddns in openwrt is event based. A service does not have to be started when booting."

I'm not understanding --

If I was using DDNS in the most common use case (running my DDNS on the actual router with a WAN interface, that response would make sense - that since ddns is "event based", then DDNS could get activated when the WAN Ip changes or when the network/interface comes up.

But in my case, this is running on a separate machine that only has a LAN interface - no WAN!

That's why I'm using "URL" external IP checker. If I'm not mistaken, this exact use case is the whole reason why the "URL" external IP checker option exists - for those of us that run DDNS updater on a device other than the device with the WAN interface....

So for those of us who use the "URL" option to check for needed DDNS updates and execute them, what is our option? Why don't we have the ability to have the DDNS scripts autostart on boot? It's important for this to happen!! If it doesn't start on boot, and the IP changes (or has already changed from the last update), then DDNS never gets updated. And if we are relying on this to VPN remotely using our DDNS hostname, we can't even fix it without physical access to the machine!

I have it set to check every 10 minutes to see if the IP has changed, but it doesn't do that at all. Once you MANUALLY start it, it DOES work properly and checks every 10 minutes and updates when it changes. We need to have the option for this to happen automatically. Perhaps an 'override' for those of us who use the URL option...

Can you help me understand why this is an issue and why the autostart doesn't take this (non event based) use-case into account?

I appreciate any input!

Actual Behaviour

ddns never starts. Does not check external IP url checker every 10 minutes as it should.

Confirmation Checklist

• The package is maintained in this repository.
• I understand that issues related to the base OpenWrt repository or LuCI repository will be closed.
• I am reporting an issue for OpenWrt, not an unsupported fork.

[feckert]

Since I somehow took over the ddns-script project and the others see me as the maintainer, I wasn't aware that there was such a use case. I only use it on my router for the WAN interface to update my ddns record.

In your case, I agree with you that this cannot be done in a event manner.

On boot all ddns section are started and the function start_daemon_for_all_ddns_sections is called.
Which section should start is discovered by the function load_all_service_sections

I think we need to start here to fix this issue. Because if this condition is not met, the service will not start.

This is just a quick analysis of the problem. No guarantee that this is correct.

[samwathegreat]

@feckert Thank you very much for your quick reply.

Last night, as a quick-fix, I came up with the following workaround on this specific install by modifying /etc/init.d/ddns 'boot' section

from this

boot() {
        return 0
}

to this

boot() {
        /usr/lib/ddns/dynamic_dns_updater.sh -- start
        return 0
}

Then I deleted /etc/rc.d/S95ddns, and then re-synlinked it from /etc/init.d/ddns

And now it starts automatically and persists on reboot.

To be honest, the event-based stuff is over my head. I'm not seeing any disadvantage to doing it this way (please let me know if there is one!).

And to be honest, I'm not really seeing the benefit of the startup being 'event driven' versus just starting the daemon on boot letting it run, doing it's checks at the specified intervals. Now I also agree that it's a VERY good idea to have UPDATES based on events (such as WAN up), what way if the wan IP changes, the update happens immediately instead of having to wait for the 'check' interval that has been configured. But why can't it just START initially at boot regardless of event? What drawback is there to those who are using it on a normal router with WAN interface?

[feckert]

Now I also agree that it's a VERY good idea to have UPDATES based on events (such as WAN up), what way if the wan IP changes, the update happens immediately instead of having to wait for the 'check' interval that has been configured. But why can't it just START initially at boot regardless of event?

As far as I can remember, the problem is that the whole ddns script stuff is written in shell 👎 , and that's a problem when the services are running all the time if the interface from netifd is not configured and therefore not connected. And as you correctly recognized, the DDNS record is updated immediately when the interface is connected.

Can you post your configuration without any secrets. I'll have to take a look at how we can solve this with your setup when I have time.

Or you can take a look yourself and open a PR to fix this and I will review this PR.

[samwathegreat]

Sure - my config is really simple (posted below) -- let me know if you need anything else. I apologize - I'm good at figuring stuff out, but I've never made a PR before and like I said, much of this is over my head...

To be clear, for my use-case and for anyone using ip_source "web" and using external web-based IP checker, I don't expect there to be any "immediate" update like there is with the wan interface triggers, since openwrt has no way of knowing that a change has occurred aside from the periodic 'checks' at the pre-configured 'check intervals'.

All I expect and need for it to do is:
-Start the service on boot, so that it keeps checking at the defined 'check interval', and updates the record if/when it changes.

That's it. So my solution of modifying the boot script is working just fine. BUT, I think that this should be normal behaviour anytime someone configures DDNS and selects IP address source as "URL" [web]. When that option is selected, the ddns script should be started on boot regardless of any 'event' trigger. Otherwise NO UPDATES HAPPEN at all unless manually started. When external ip address checking source is not selected, no changes are needed from the way it currently works.

Do you agree?

root@openwrt-fs:/etc/config# cat ddns

config ddns 'global'
        option ddns_dateformat '%F %R'
        option ddns_loglines '250'
        option ddns_rundir '/var/run/ddns'
        option ddns_logdir '/var/log/ddns'

config service 'fs'
        option service_name 'cloudflare.com-v4'
        option use_ipv6 '0'
        option enabled '1'
        option lookup_host 'abc.xyz.com'
        option domain 'abc@xyz.com'
        option username 'Bearer'
        option password 'super-secret-token'
        option use_https '1'
        option cacert '/etc/ssl/certs'
        option ip_source 'web'
        option ip_url 'http://checkip.dyndns.com'
        option interface 'eth0'
        option bind_network 'lan'
        option use_syslog '2'
        option check_interval '10'
        option check_unit 'minutes'
        option force_interval '72'
        option force_unit 'hours'
        option retry_unit 'seconds'