[lwip-users] How to disable TCP backlog properly?

[pavel a]

Dear experts,

I have an embedded TCP server that should have only one long lived connection.

Once a client connects, the server should not accept anything else.

The program calls netconn_listen, then netconn_accept() and will not call accept() again until the client disconnects.

Is it correct to define TCP_LISTEN_BACKLOG = 0 for this case? (or leave it undefined)

 

What I see is that another client program from same host  (Windows 10) connects successfully. At least it thinks so.

When the 2nd client tries to send something, it disrupts the 1st client: the server cannot send to it and cannot receive.

The 2nd client cannot do anything as well.

The question is how another client manages to connect without accept() and how to prevent this.

 

LwIP version is 2.1.2 (st.com fork for STM32)

 

Thanks in advance