Re: [lwip-users] Consecutive calls to sendto() and recvfrom() functions

[Sergio R. Caprile]

> Sergio, can you just explain what you mean by third sentence, how can 
> I check all those things (port, driver) and what is known-to-work app?

lwIP is not and end-user full contained product, it starts at layer-3 
(IP) and runs on some hardware, it has been ported to that hardware.
Your layer-2 driver might just be discarding/losing frames, for example; 
or your hardware might be doing that.
A known-to-work application is an application that is known to work ;^), 
that is, it is not something you are writing yourself while you learn 
how to use lwIP but something that has been proved OK. For example, the 
examples in the contrib tree.
Since your hardware can be faulty, your driver can be faulty, your port 
can be faulty, and your application can be faulty, you have to eliminate 
variables (faulty stuff), so if one of the examples do not work for you, 
either your hardware, your port or your driver (sometimes both...) are 
the culprit. Most of the times, your driver can be checked alone, and 
your port can sometimes be checked for doing things the proper way, that 
is, only calling low-level functions from within a single thread; 
sockets and netconns can be called each one from its thread. RTOS ports 
(NO_SYS=0) use some semaphores, you can search the list for a priority 
problem, I bet the FreeRTOS port is running OK, but depends on where you 
get it from...
You should also read the wiki... http://lwip.wikia.com/wiki/LwIP_Wiki