CODEWITHSUNDEEP
cembeddeddhcp
amitp
amitp

Reputation: 283

Detect if IP is static or obtained from DHCP on busybox

I am working on embedded device who run BusyBox.
The system is getting its address by using the ip command. I want to figure out from my C program whether the device ip static or received from DHCP server. How do I do that?

Upvotes: 1

Views: 5542

Answers (4)

Troglobit
Troglobit

Reputation: 41

I don't know how your users interact with your embedded system. But on ours (same components) we have CLI that registers the chosen DHCP/STATIC type setting in a SHM struct (db) per interface.

Essentially, you need to keep track of how the IP of an interface was set.

Upvotes: 4

gnud
gnud

Reputation: 78618

If you control the enviroment, I suggest setting an env variable, or creating a flag file somewhere you can stat, when the IP adress is set.

Upvotes: 0

Adam Liss
Adam Liss

Reputation: 48330

Take a look at this question and check the IFF_DYNAMIC flag - that may be set when DHCP is active on an interface.

Upvotes: 1

unwind
unwind

Reputation: 400109

The dumpleases command is supposed to show the current leases. I guess if you can determine that you have an IP address, but no lease, then the address is static.

Upvotes: 1

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