STM32 LwiP Multiple TCP Server

Question

I tried to do a 3 or 4 tcp server on my STM32F107. I'm using freeRTOS and LwIP (and the CubeMX + ST HAL library).

I create a task tcp_server, and inside the task, I create 3 netconn structure each with different tcp port. Callback:

void socket_callback(struct netconn * conn, enum netconn_evt evt, u16_t len)
{
    queue_event_t msg;
    if (evt == NETCONN_EVT_RCVPLUS)
    {
            msg.cmd = MSG_TEST;
            if (conn == user_conn.conn_modbus)
                msg.cmd = MSG_MODBUS;
            else if (conn == user_conn.conn_modbus_listen)
                msg.cmd = MSG_MODBUS_LISTEN;
            else if (conn == user_conn.conn_rs232)
                msg.cmd = MSG_RS232;
            else if (conn == user_conn.conn_rs232_listen)
                msg.cmd = MSG_RS232_LISTEN;
            else if (conn == user_conn.conn_rs485)
                msg.cmd = MSG_RS485;
            else if (conn == user_conn.conn_rs485_listen)
                msg.cmd = MSG_RS485_LISTEN;
            xQueueSend(user_conn.evtQueue, &msg, 1000);
    }
}

Server creation :

static struct netconn * createServer(int port) 
{
    struct netconn * conn;
    err_t err;

    conn = netconn_new_with_callback(NETCONN_TCP, socket_callback);
    if (conn == NULL) 
    {
          char *msg = "Cannot create netconn\n\r";
          HAL_UART_Transmit(&huart3, (uint8_t*)msg, strlen(msg), 0xFFFF);
          return NULL;
    }

    err = netconn_bind(conn, NULL, port);
    if (err != ERR_OK)
    {
        char *msg = "Error in Binding \n\r";
        HAL_UART_Transmit(&huart3, (uint8_t*)msg, strlen(msg), 0xFFFF);
        print_error(err);
        netconn_delete(conn);
        return NULL;
    }
    err = netconn_listen(conn);
    if (err != ERR_OK)
    {
      char *msg = "Error in listenning \n\r";
      HAL_UART_Transmit(&huart3, (uint8_t*)msg, strlen(msg), 0xFFFF);
        print_error(err);
        netconn_delete(conn);
        return NULL;
    }
    return conn;
}

Thread :

static void servertcp_thread()
{
    queue_event_t evt;
    user_conn.evtQueue = xQueueCreate(10, sizeof (queue_event_t));
    user_conn.conn_modbus_listen = createServer(502);
    user_conn.conn_rs232_listen = createServer(10001);
    user_conn.conn_rs485_listen = createServer(50001);

    while(1)
   {
        waitServer(&user_conn, &evt);
        send_rs232(&user_conn);
        send_rs485(&user_conn);
        if((user_conn.conn_modbus_listen != NULL) && (evt.cmd == MSG_MODBUS_LISTEN))
            processModbusListen(&user_conn);
        if((user_conn.conn_rs232_listen != NULL) && (evt.cmd == MSG_RS232_LISTEN))
            processRS232Listen(&user_conn);
        if((user_conn.conn_rs485_listen != NULL) && (evt.cmd == MSG_RS485_LISTEN))
            processRS485Listen(&user_conn);
        if((user_conn.conn_modbus != NULL) && (evt.cmd == MSG_MODBUS))
            modbus_tcp_server(&user_conn);
        if((user_conn.conn_rs232 != NULL) && (evt.cmd == MSG_RS232))
            rs232_tcp_server(&user_conn);
        if((user_conn.conn_rs485 != NULL) && (evt.cmd == MSG_RS485))
            rs485_tcp_server(&user_conn);
   }
}

The creation is successful (netconn_new_with_callback / netconn_bind and netconn_listen with no error).

When I tried to connect to 1 tcp port, it is accepted and everything is ok.

But when I tried to connect to a second port while the first connexion is still alive, the callback is called, but the netconn_accept(conn, &newconn); failed and report ERR_ABRT and I don't know why.

The 3 function (processModbusListen, processRS232Listen and processRS485Listen) are coded following the same prototype:

static int processXXXListen(user_conn_t * user_data) 
{
    struct netconn *newconn;
    err_t error_accept;
    error_accept = netconn_accept(user_data->conn_XXX_listen, &newconn);
    if (error_accept == ERR_OK)
    {
        if (user_data->conn_rs485)
        {
            // Close unwanted connection
            netconn_close(newconn);
            netconn_delete(newconn);
            char *msg = "Error XXX Connection during establishement\n\r";
            HAL_UART_Transmit(&huart3, (uint8_t*)msg, strlen(msg), 0xFFFF);
        }
        else
        {
            // connection established
            char *msg = "XXX Connection established\n\r";
            HAL_UART_Transmit(&huart3, (uint8_t*)msg, strlen(msg), 0xFFFF);
            user_data->conn_XXX = newconn;
        }
    }
    else
    {
        char *msg = "Error in acceptation TCP XXX connection\n\r";
        HAL_UART_Transmit(&huart3, (uint8_t*)msg, strlen(msg), 0xFFFF);
        print_error(error_accept);
    }
    return 0;
}

The strange thing is, that when i only create 2 netconn structure, i have no problem with the 2 connection in the same time.

What can cause the connexion aborted ? How can i get the 3 connection in the same time ? If it is possible of course ...

Answer 1

Ok, yes after 1day of testing, the param

#define MEMP_NUM_NETCONN 4

is definetly what makes me troubl. i just have to set it to 10, and everything works like a charm