Re: [lwip-users] Best practice for DHCP/Static IP config

[address@hidden]

Am 22.01.2019 um 09:58 schrieb address@hidden:
> Could I get a recommendation for run-time configurable DHCP/Static IP 
> address. Sorry if this has been asked 100 times before. Just wondering 
> what the people who actually use lwip do…
>
>  From monitoring the mailing list, I understand no graceful shutdown… So 
> I am ok with a startup variable and reset the hardware to make the 
> setting take effect. #define is not really what I am looking for.
>
> Is this the right way?
>
>  1. Start the stack
>  2. Check my config for desired static IP, or DHCP requested (dip
>     switch, config bit, etc)
>
> netif_set_default()
>
> if (dhcp)
>
>          dhcp_start();
>
> else
>
>          netif_set_up();

No, that was old usage. It has been changed with 2.0.0: you now *always* 
need to set the netif up. Then call dhcp_start() or net_set_addr().

> A pointer to an example that does this, or 5 lines of pseudo code would 
> be great!

There is 'contrib\examples\example_app\test.c', but this file is 
somewhat of a bad example since it tries to include all possible code 
with ifdefs...

So:
netif_add() // either with satic IP address or call netif_set_addr() later
netif_set_default()
netif_set_up()
if (dhcp)
        dhcp_start();
else
        netif_set_addr(); // if not set with netif_add()

And remember that the netif has to set the link flag up 
('netif_set_link_up()') for things to work.

> (SAME54, lwip 2.0.3, free RTOS 10.0.0)
>
> Thanks Simon, Sylvain,  Steve, Patrick, and others who are providing 
> such great help to this list! Most of my questions are answered by just 
> watching the emails on this list.

Good to know!

Regards,
Simon