Re: [lwip-users] Multi-Threaded netconn API TCP application

[Pîrvu Mihai]

Thing is that's exctly what I done before this approach. Here's a similar code that I tried, where I create an array of sessions and look for the first one that's available, and use that one to accept a new connection. I have exactly the same problem: First client connects well, we can communicate, I receive his messages and I can send him messages back.

Then, whenever a second client tries to connect it's automatically disconnected. Also, if i disconnect the first client and try to connect him back, he also can't connect anymore, gets instantly disconnected.

Here's a log of what I mean:

Connected: 0 //client "0" connects with netcat

Received from 0 : a //client sends messages

Received from 0 : b

Received from 0 : c

Connected: 1 //client "1" connects with netcat

Disconnected: 1 //disconected immediately

Disconnected: 0 //I close the connection of clent "0"

Connected: 0 // I try to connect again with client "0"

Disconnected: 0 //Same problem as client "1"

Connected: 0 

Disconnected: 0

Here's the current code: http://pastebin.com/1eQd9dzQ

Mihai

On Sun, Sep 20, 2015 at 2:05 PM, Pîrvu Mihai <address@hidden> wrote:

Hello guys, I'm sorry if this was posted before, but i couldn't find an answer, so I'm gonna post here in search of one.

I want to create a simple multi-threaded TCP server, that handled each new connection on a separate thread. The listener thread will listen on the "main" thread, and every connection will create a new thread, that will communicate with the session created.

The code I wrote is here: http://pastebin.com/zUuTtfL0

I have dug a little into the lwip API to see how netconn_accept works and I saw that it blocks until the "not_empty" semaphore frm the "acceptbox" mailbox has something in it. 

Now, every time this happens, I create a new thread and the session creation is done there, and I block the main thread using the "semaphore" variable, so a new connection doesn't happen while I still proces the old one.

Now, the problem is pretty much this:

- I connect the first client, it works just fine

- When ANY second client tries to join, it automatically gets disconnected and the server's console prints: Disconnected: 1, so netconn_recv doesn't return ERR_OK.

So my question is:

- How can I create this multi-threaded enviroment so each client is processed in a different thread?

- Also, what am I doing wrong in my current setup ?

PS: The application runs on Linux atm, using lwip 1.4.0 (last stable one), the unix port from contrib directory and the clients connect using netcat <ip> <port>.

Mihai