Ping... this question seemed to be waiting on our mailing list for several days:
On Tue, Jun 30, 2020 at 4:58 AM Reto Gähwiler <gret.hexa...@gmail.com> wrote: > I am facing the following problem working with nuttx and ethernet > connections. A TCP socket is setup as blocking and connected to the server. > The connection is handled in one thread which hangs in the recv call and > processes the data if some arrives. In case of an error the connection is > closed. > Now, if a close() call on that particular TCP connection is called from a > different thread, it terminates the connection and the recv() fails and > breaks free. > If we now connect to a new IP, it first seems to be fine but shortly after > the whole network disappears. No more icmp responses (therefore no ping) > and all other opened connections in different threads are not reachable > anymore. Besides, any of the still opened connections starts to consume all > cpu time. Looking into it with the debugger attached it can be seen, > that in the net/devif/devif_callback.c the for-loop looking for the > callback in the device event list is cycling without an end. (snip) > I was wondering if anyone else ran into the issue of calling close on a > socket from a different thread as the recv/send is handled on and that the > following connection kills the entire ethernet? Please let me know if you > know a fix for blocking sockets or it would be better to go with > non-blocking and work with select/poll instead. Hi Reto, Have you considered trying to put all the handling into a single thread and using some sort of inter-thread messaging to request that thread to close the connection when no longer needed? I don't know the answer to calling close() from another thread because I have always written my networking code to manage a socket by a single thread, where all operations on the socket occur in that same thread. If your concern is blocking while waiting to recv() or recvfrom(), I use select() to check whether any received data is waiting, usually with a timeout so that the thread can do other things while it waits for data. Hopefully someone else can chime in about your specific question. Nathan
