[lwip-users] [lwip] Beginner's problems and questions

[Wurmsdobler, Peter]

Hello,

First and in advance many thanks to Adam for his excellent work and
providing it to a community. Since I am a beginner in TCP/IP stack
implementation, I have some questions:

1. Given the distribution, is there any template for makefiles in order
   to build a generic tree ?

2. What should be compiled and linked together for a special target?
   api arch/$arch core core/ipv4 netif ? This is not so obvious for me.
   A document on the web speaks about core/ipv4 and arch/$ARCH/*_arch.c

3. Having made my own Makefiles in the dirs I think are necessary, I got
   many compile errors, in particular "conflicting types for
`PACK_STRUCT_STRUCT'"
   (I did ot understand its use so far). But there are still others.
   Most arise of many dependences and multiple definitions.

4. I assume that certain functions have to be provided for a specific
architecture,
   which is somewhere in arch/$ARCH/lib_arch.c and arch/$ARCH/sys_arch.c
with
   their header files in the respective dirs. In a single threaded
environment
   (no OS) what must the sem and block functions look like?

5. So far I prefer to force lwIP to use only pool buffers as I anticipate
more
   predictible performance in a control environment. Is there a good means
to
   just remove everything related to dynamic allocation? Is this also
possible
   for a pool of PCBs (I did not understand yet the PCB allocation).

6. pbuf.c uses a pbuf_pool and a cache. What would happen if only a single
   linked list is used for free buffers. What is the benefit of using the
   cache (alocating from pbuf_pool, freeing into the cache, and then
refreshing
   from the one into the other. Or do I miss a major OS point?
  
Thanks a lot for any hints,
peter

Peter Wurmsdober
Eurotherm Drives Ltd.
Littlehampton, BN17 7RZ, UK
TEL: +44 19 03 73 73 58
FAX: +44 19 03 73 71 07
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