udhcpc: udhcpc not stopping due to Ethernet power down

[Alexander Dahl]

Hei hei,

Am Dienstag, 12. Juni 2018, 14:07:39 CEST schrieb Bryan Evenson:
> using udhcpc for its wired Ethernet port.  The startup script is calling
> udhcpc as follows:
> 
> 	udhcpc -R -b -p /var/run/udhcpc.eth0.pid -i eth0

[…]

> I've been having some networking issues with this device, and I found out
> that the cable modem its connected to is set to power down the Ethernet
> connection after two minutes with no traffic.  I do have something a task
> that uses the network every four minutes, but nothing is guaranteed to
> operate more frequently than that.  When I finally logged onto my device, I
> found out that there were about 100 instances of udhcpc up and running.  I
> believe each time the Ethernet port is enabled udhcpc starts back up again,
> but for some reason the old instance of udhcpc keeps running.

Is there some other mechanism active besides your startup script, which starts 
udhcpc? Maybe 'ifup' based on the settings in /etc/network/interfaces does 
this? (Depending on how you configured busybox/udhcpc, ifup, etc. when 
compiling.)

Did you look at the command line of those 100 instances? Are those exactly the 
same as if you start udhcpc with the startup script? If not, probably those 
are not started with your startup script. If yes, maybe some other mechanism 
starts your startup script again?

Do you have something running which reacts on cable plugging/unplugging like 
ifplugd? Maybe you find hints on what's going on in the configuration of that?

Greets
Alex