Problem with TCP socket

Troubleshooting
1

Hi,

I wrote a little program which uses the TCPServer. This works to some extent but has some problems:

  • The connection works for the first time, but when closing down the connection and reopening another connection, it is often very slow, or the connection does not work at all.
  • After a while it often won’t accept new connections anymore.
  • While the connection is open, it works for some while, but after a while of inactivity the connection is shut down by the spark core.

I reduced the program to one which only uses only the basic socket APIs. That one has the same problems. So it is not a problem with TCPServer code.

It seems that if waiting a while before reconnecting it works fine. So the issue seems to be accepting too many connections in a too short amount of time.

Here is the program (I put it into application.cpp and upload use dfu-util). This is running all the code in the loop without ever leaving the loop, but also exiting from the loop each time has the same effect.

#include "application.h"

void setup()
{
    pinMode(7, OUTPUT); 
}    

void loop()
{
    sockaddr tServerAddr;
    tServerAddr.sa_family = AF_INET;
    short port = 80;
    tServerAddr.sa_data[0] = (port & 0xFF00) >> 8;
    tServerAddr.sa_data[1] = (port & 0x00FF);
    tServerAddr.sa_data[2] = 0;
    tServerAddr.sa_data[3] = 0;
    tServerAddr.sa_data[4] = 0;
    tServerAddr.sa_data[5] = 0;    

    int sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (sock < 0)
        return;
    if (bind(sock, (sockaddr*)&tServerAddr, sizeof(tServerAddr)) < 0)
        return;
    if (listen(sock, 0) < 0)
        return;    

    while (true)
    {
        sockaddr tClientAddr;
        socklen_t tAddrLen = sizeof(tClientAddr);
        int client = accept(sock, (sockaddr*)&tClientAddr, &tAddrLen);
        if (client < 0)
            continue;

        while (true)
        {
            char buffer[1024];
            int readBytes = recv(client, buffer, sizeof(buffer), 0);
            if (readBytes < 0)
                break;
            if (buffer[0] == '1')
            {
                digitalWrite(7, true);
                if (send(client, "on\n", sizeof("on\n"), 0) < 0)
                    break;
            }
            else if (buffer[0] == '0')
            if (buffer[0] == '1')
            {
                digitalWrite(7, false);
                if (send(client, "off\n", sizeof("off\n"), 0) < 0)
                    break;
            }
            else if (buffer[0] == 'q')
            {
                send(client, "quit\n", sizeof("quit\n"), 0);
                break;
            }    

        }
        closesocket(client);
    }
}

I also updated the CC3000 using the new cc3000-patch-programmer, but that did not improve anything. I tried too boards, they both have the same issue.

I am bit puzzled. It seems this is a problem with the CC3000. But that one is used in many applications and I have problems imagining that it is that buggy. Any hints about would I could be doing wrong?