Re: [lwip-users] Noob DHCP question

[address@hidden]

Kieran Mansley wrote:
> On 15 Mar 2012, at 15:37, Chris Ponder wrote:
>
> > At the application level I want to know when I have an address, if there is an 
> > error getting an address, if the network lead is disconnected / re-connected so 
> > that I can restart the Ethernet or set a static address as I see fit.
> I'm not sure what the supported way of doing this is, but I'm sure that other 
> people do similar things to this.  Can anyone help Chris with some suggestions 
> here please?

- "when I have an address": you can register a callback with 
netif_set_status_callback() that gets called when the netif is set up or 
down. Since DHCP sets it to 'up' after getting an address, is this what 
you want?
- "the network lead is disconnected": you can register a callback with 
netif_set_link_callback(), but for this callback to work, your netif 
driver needs to notify lwIP of link state changes by calling 
netif_set_link_up() / netif_set_link_down().
- "if there is an error getting an address": I'm not sure how to do 
that: DHCP just keeps on trying. Maybe you can just use a timeout and do 
something if you didn't get an address X seconds after the link went 
from 'down' to 'up'?

Simon