[lwip-users] Noob DHCP question
Chris Ponder
Hi all,
I have set up DHCP running on lwIP 1.4.0 standalone and it is working wonderfully in that it is getting an address and assigning it to an interface.
My question is, how do I interrogate the DHCP information?
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.
How do I do this?
Cheers
Chris
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Kieran Mansley
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?
Thanks
Kieran
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> 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