Re: [lwip-users] Receving file from web server using raw TCP

[Sergio R. Caprile]

Yes, you are debugging your application, the port and the layer-2 driver
at the same time...
I suggest you take a known to work application from the contrib tree and
validate port and driver.
Start with simple pings, then move to a netio or echo. The netio app is
rather simple (incomplete), check for some unapplied patches in the
proper section, I guess there are (at least) two. I wrote one of them
and even though it hasn't been extensively tested, it worked OK on my
setup with various segment sizes.

Enable statistics gathering and poll them frequently, that should lead
you to memory problems.

>> The "myclose()" function is not a simple call to tcp_close(pcb) because
>> it may fail and you need to retry later by means of the poll callback or
>> your own method.

What I usually do is check the result of tcp_close(), if it is not
ERR_OK then the tcp_poll() callback will retry. this requires a state
variable, though.