[lwip-users] LWIP Multithreaded Issues into RAW interface/Critical Section Protection, etc.

[Scott Taggart]

Hi,

I have used and looked at the LWIP “blocking” API (api_lib.c, etc.) and see that it effectively serializes all access to the LWIP raw TCP interface.  I think I remember some threads on this forum stating that the LWP TCP raw interface is not thread safe and, thus, the blocking api implemented serialization.  Can anyone confirm that on a multi-threaded system I will need to serialize/mutually exclude all calls into the TCP raw interface?  If so, what are the issues about when I get a TCP callback (say for receiving data) and I want to issue another TCP call from within that callback.  Seems like deadlock situations or unintended re-entrantcy would be hard to avoid.  I suppose another way to phrase this is: does the RAW TCP interface protect its critical sections and reentrantcy?

And comments would be appreciated.  If someone has dealt with these issues, I would like to hear what mechanisms you used.

Thanks,

Scott