Terminate on either WiFi or eth0 connection

[sistemicorp]

In my application, the Raspberry Pi (4B) can be connected either via WiFi or ethernet cable.

I would like the comitup hotspot to terminate if there is a connection on eth0.

Would there be some hints as to how to achieve this within the comitup code?

My application listens on port 80, so therefore it will not start when comitup hotspot is running.

I could have a shell script check for internet connection and then use systemctl to stop comitup.

I am a python programmer so I could modify the code, but I am not a networking guy. I would prefer to modify the comitup code so that if it found there was a connection on eth0, it would call the callback function with "CONNECTED". I could use some hints about doing this.

[davesteele]

The place in the comitup code for that would be hotspot_start() and hotspot_timeout() in states.py.
... but that may not a particularly good place. Looking at the current code status, the timeout is sometimes called every 5 seconds, and sometimes every 3 minutes (if no AP connections are defined). I've done much fiddling with that number in the past - I'm not sure if setting it to 5 seconds always would be OK.
You could kill comitup externally, but you would also be responsible for tearing down the AP via nmcli.

[davesteele]

Logically, the comitup fix might be best solved by adding another state, for "ethernet active and kill-comitup-activity-when-ethernet is set".

[davesteele]

If I may be so bold as to suggest another feature, for the hotspot SSID, it would be nice to have last 4 digits of MAC address, or RPi serial number

I'd be happy to see those options show up for ap_name.

[sistemicorp]

My intent is to start today. I already have python code that can get MAC and RPi Serial number from another project I have.

Any suggestions for why I don't see eth0 disconnecting event(s)?
My only lead is that there perhaps should be an entry in NetworkManager.conf for eth0.... But I think comitup manages that file, so I was reluctant to touch it yet, without further understanding.

I also wondering if there is a way to "kick" NetworkManager to make it publish all the current states of the devices (though specifically eth0). I think I need this because on boot, almost half the time comitup doesn't get the eth0 connecting states, I assume those events happened before comitup service was running (as the eth0 cable was plugged in on power up). Googling the APIs I haven't seen the way to do this. The other way would be to read eth0 state when comitup initialises...

[davesteele]

Any suggestions for why I don't see eth0 disconnecting event(s)?

No. any_changed_state() should be seeing the state changes associated with that. There may be another NM signal to listen to.

[davesteele]

an entry in NetworkManager.conf for eth0.... But I think comitup manages that file

No. The Comitup Image defines a pair of NM connections, so that it will auto-connect DHCP or static, as appropriate. But it is all NM after that, and the package doesn't know from wired connections.

[sistemicorp]

I have working prototype for specifying the use of partial MAC or RPi serial number, in the same way that random number was used. Before I post code, a few comments to clarify things, and/or to change the way it works...

1. The MAC and SN use the back end digits, not from the front. For example if the serial number is 10000123, then specifying <sss> will get you 123.
2. I threw in extra code that determines if the MAC or SN needs to be fetched, if ap_name doesn't call for it, then don't bother getting it. This is an attempt to have no impact on existing (working) systems. The new MAC/SN fetching code might not work on an older system or something. I am always paranoid.
3. I added some validation... if the ap_name spec in the conf file doesn't look right, fall back to default.