[lwip-users] Where is Read()Write() functions that I must overload?

[Лайт Ягами]

Hello all.

I am trying to use TCP/IP through a lwIP for communicating with a RS-232 device. The problem is that I am the third day wander in the source code, and I can't find at all where is the Read()/Write() (or something like this) functions that I should overload to make the stack work.

In the ethernetif.c file I found the low_level_output() function. As the description says "This function should do the actual transmission of the packet" -- excellent, that's exactly what I wanted! But there is a problem: in the actual code no a function with this name used at all!

I also found the sys_arch_mbox_fetch() function. I am using the sys_arch.c file from the "ports" directory, and the function that there is present seems to be a thing-in-itself -- it also doesn't do any receiving a message, it just waiting for a mbox struct to be changed -- seems, this should be changed by an otherworldly force. So this doesn't seem to be the function, I am looking for.

So, what is the functions that doing an actual transmission/receiving a data?