Re: [lwip-users] 2 Devices

[Fabian Cenedese]

At 15:20 07.11.2017, you wrote:
>Hi, 
>
>I am doing similar thing. I think I will use one thread to collect data from 
>multiple devices and feed them to corresponding netif->input.
>Don't feed data directly to tcpip_input, if you do so, make sure you pass the 
>right netif to it. Anyway make sure you have two individual netif.

I do have two netifs, as mentioned before, I call netif_add/setup twice.
Reading and processing the incoming frames is one thing, sending the
reply back over the same interface is another.

>For UDP, I believe you can bind with IP_ANY to listen on same port on all 
>devices. In UDP recv callback, you can find the source IP in the parameters.

I already bind with sin_addr.s_addr=PP_HTONL(INADDR_ANY),
but this fails on the second bind. Somehow makes sense
as LwIP wouldn't know which one to give an incoming frame. But if the
sockets were netif specific then it would be possible for both netifs to listen
on the same port.

>Are you working on something like a router? If so, what protocol you are 
>working on and do you have any code resources to share, please?

No, this is not a router but our main fieldbus CPU. One interface would be
used for loading, communication, visualisation etc. The other interface
could be used by the customer to access any network device, be it
TCP/IP or Profinet, Modbus, whatever.
The operating system is only open to our customers, sorry. But the
LwIP part is still standard so far. But that may change now.

Thanks

bye  Fabi