problem receiving multiple data with ethernet

[Dreamer3D]

Hello,

I'm using an STM32 F4 board as a TCP Server and the hercule application on my PC as a TCP Client.

I follow the online tutorial proposed by controllersTech for the configuration.

This is what my program does: If I send the message "1" to the server then he replays me back some message. And if I send message other than "1" then he replays me back some other message.

The connexion work well and I can interact with the server for 9 interactions, after that, I can no longer interacting with the server.

Here are my code:

#include "tcpserverRAW.h"

#include "lwip/tcp.h"
#include <string.h>

/*  protocol states */
enum tcp_server_states
{
  ES_NONE = 0,
  ES_ACCEPTED,
  ES_RECEIVED,
  ES_CLOSING
};

struct tcp_server_struct
{
  u8_t state;             /* current connection state */
  u8_t retries;
  struct tcp_pcb *pcb;    /* pointer on the current tcp_pcb */
  struct pbuf *p;         /* pointer on the received/to be transmitted pbuf */
};

#define SIZE_BUFFER 50
char buf_rx[SIZE_BUFFER];
char buf_tx[SIZE_BUFFER + 20];

extern TIM_HandleTypeDef htim2;
int button_state = 0;
struct tcp_pcb *tpcb_loop;
struct tcp_server_struct *es_loop;

static err_t tcp_server_accept(void *arg, struct tcp_pcb *newpcb, err_t err);
static err_t tcp_server_recv(void *arg, struct tcp_pcb *tpcb, struct pbuf *p, err_t err);
static void tcp_server_error(void *arg, err_t err);
static err_t tcp_server_poll(void *arg, struct tcp_pcb *tpcb);
static err_t tcp_server_sent(void *arg, struct tcp_pcb *tpcb, u16_t len);
static void tcp_server_send(struct tcp_pcb *tpcb, struct tcp_server_struct *es);
static void tcp_server_connection_close(struct tcp_pcb *tpcb, struct tcp_server_struct *es);

static void tcp_server_handle (struct tcp_pcb *tpcb, struct tcp_server_struct *es);

void tcp_server_init(void)
{
	/* 1. create new tcp pcb */
	struct tcp_pcb *tpcb;

	tpcb = tcp_new();

	err_t err;

	/* 2. bind _pcb to port 7 ( protocol) */
	ip_addr_t myIPADDR;
	IP_ADDR4(&myIPADDR, 172, 16, 1, 2);
	err = tcp_bind(tpcb, &myIPADDR, 7);

	if (err == ERR_OK)
	{
		/* 3. start tcp listening for _pcb */
		tpcb = tcp_listen(tpcb);

		/* 4. initialize LwIP tcp_accept callback function */
		tcp_accept(tpcb, tcp_server_accept);
	}
	else
	{
		/* deallocate the pcb */
		memp_free(MEMP_TCP_PCB, tpcb);
	}
}

static err_t tcp_server_accept(void *arg, struct tcp_pcb *newpcb, err_t err)
{
  err_t ret_err;
  struct tcp_server_struct *es;

  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_14, GPIO_PIN_SET);

  LWIP_UNUSED_ARG(arg);
  LWIP_UNUSED_ARG(err);

  /* set priority for the newly accepted tcp connection newpcb */
  tcp_setprio(newpcb, TCP_PRIO_MIN);

  /* allocate structure es to maintain tcp connection information */
  es = (struct tcp_server_struct *)mem_malloc(sizeof(struct tcp_server_struct));
  if (es != NULL)
  {
    es->state = ES_ACCEPTED;
    es->pcb = newpcb;
    es->retries = 0;
    es->p = NULL;

    /* pass newly allocated es structure as argument to newpcb */
    tcp_arg(newpcb, es);

    /* initialize lwip tcp_recv callback function for newpcb  */
    tcp_recv(newpcb, tcp_server_recv);

    /* initialize lwip tcp_err callback function for newpcb  */
    tcp_err(newpcb, tcp_server_error);

    /* initialize lwip tcp_poll callback function for newpcb */
    tcp_poll(newpcb, tcp_server_poll, 0);

    tpcb_loop = newpcb;
	es_loop = es;

	//HAL_TIM_Base_Start_IT(&htim2);

    ret_err = ERR_OK;
  }
  else
  {
    /*  close tcp connection */
    tcp_server_connection_close(newpcb, es);
    /* return memory error */
    ret_err = ERR_MEM;
  }
  return ret_err;
}

static err_t tcp_server_recv(void *arg, struct tcp_pcb *tpcb, struct pbuf *p, err_t err)
{
  struct tcp_server_struct *es;
  err_t ret_err;

  LWIP_ASSERT("arg != NULL",arg != NULL);

  es = (struct tcp_server_struct *)arg;

  /* if we receive an empty tcp frame from client => close connection */
  if (p == NULL)
  {
    /* remote host closed connection */
    es->state = ES_CLOSING;
    if(es->p == NULL)
    {
       /* we're done sending, close connection */
       tcp_server_connection_close(tpcb, es);
    }
    else
    {
      /* we're not done yet */
      /* acknowledge received packet */
      tcp_sent(tpcb, tcp_server_sent);

      /* send remaining data*/
      tcp_server_send(tpcb, es);
    }
    ret_err = ERR_OK;
  }
  /* else : a non empty frame was received from client but for some reason err != ERR_OK */
  else if(err != ERR_OK)
  {
    /* free received pbuf*/
    if (p != NULL)
    {
      es->p = NULL;
      pbuf_free(p);
    }
    ret_err = err;
  }
  else if(es->state == ES_ACCEPTED)
  {
    /* first data chunk in p->payload */
    es->state = ES_RECEIVED;

    /* store reference to incoming pbuf (chain) */
    es->p = p;

    /* initialize LwIP tcp_sent callback function */
    tcp_sent(tpcb, tcp_server_sent);

    /* handle the received data */
    tcp_server_handle(tpcb, es);

    ret_err = ERR_OK;
  }
  else if (es->state == ES_RECEIVED)
  {
    /* more data received from client and previous data has been already sent*/
    if(es->p == NULL)
    {
      es->p = p;

      /* handle the received data */
      tcp_server_handle(tpcb, es);
    }
    else
    {
      struct pbuf *ptr;

      /* chain pbufs to the end of what we recv'ed previously  */
      ptr = es->p;
      pbuf_chain(ptr,p);
    }
    ret_err = ERR_OK;
  }
  else if(es->state == ES_CLOSING)
  {
    /* odd case, remote side closing twice, trash data */
    tcp_recved(tpcb, p->tot_len);
    es->p = NULL;
    pbuf_free(p);
    ret_err = ERR_OK;
  }
  else
  {
    /* unknown es->state, trash data  */
    tcp_recved(tpcb, p->tot_len);
    es->p = NULL;
    pbuf_free(p);
    ret_err = ERR_OK;
  }
  return ret_err;
}

/**
  * @brief  This function implements the tcp_err callback function (called
  *         when a fatal tcp_connection error occurs.
  *   arg: pointer on argument parameter
  *   err: not used
  * @retval None
  */
static void tcp_server_error(void *arg, err_t err)
{
  struct tcp_server_struct *es;

  LWIP_UNUSED_ARG(err);

  es = (struct tcp_server_struct *)arg;
  if (es != NULL)
  {
    /*  free es structure */
    mem_free(es);
  }
}

/**
  * @brief  This function implements the tcp_poll LwIP callback function
  *   arg: pointer on argument passed to callback
  *   tpcb: pointer on the tcp_pcb for the current tcp connection
  * @retval err_t: error code
  */
static err_t tcp_server_poll(void *arg, struct tcp_pcb *tpcb)
{
  err_t ret_err;
  struct tcp_server_struct *es;

  es = (struct tcp_server_struct *)arg;
  if (es != NULL)
  {
    if (es->p != NULL)
    {
      tcp_sent(tpcb, tcp_server_sent);
      /* there is a remaining pbuf (chain) , try to send data */
      tcp_server_send(tpcb, es);
    }
    else
    {
      /* no remaining pbuf (chain)  */
      if(es->state == ES_CLOSING)
      {
        /*  close tcp connection */
        tcp_server_connection_close(tpcb, es);
      }
    }
    ret_err = ERR_OK;
  }
  else
  {
    /* nothing to be done */
    tcp_abort(tpcb);
    ret_err = ERR_ABRT;
  }
  return ret_err;
}

/**
  * @brief  This function implements the tcp_sent LwIP callback (called when ACK
  *         is received from remote host for sent data)
  *   None
  * @retval None
  */
static err_t tcp_server_sent(void *arg, struct tcp_pcb *tpcb, u16_t len)
{
  struct tcp_server_struct *es;

  LWIP_UNUSED_ARG(len);

  es = (struct tcp_server_struct *)arg;
  es->retries = 0;

  if(es->p != NULL)
  {
    /* still got pbufs to send */
    tcp_sent(tpcb, tcp_server_sent);
    tcp_server_send(tpcb, es);
  }
  else
  {
    /* if no more data to send and client closed connection*/
    if(es->state == ES_CLOSING)
      tcp_server_connection_close(tpcb, es);
  }
  return ERR_OK;
}


/**
  * @brief  This function is used to send data for tcp connection
  *   tpcb: pointer on the tcp_pcb connection
  *   es: pointer on _state structure
  * @retval None
  */
static void tcp_server_send(struct tcp_pcb *tpcb, struct tcp_server_struct *es)
{
  struct pbuf *ptr;
  err_t wr_err = ERR_OK;

  while ((wr_err == ERR_OK) &&
         (es->p != NULL) &&
         (es->p->len <= tcp_sndbuf(tpcb)))
  {

    /* get pointer on pbuf from es structure */
    ptr = es->p;

    /* enqueue data for transmission */
    wr_err = tcp_write(tpcb, ptr->payload, ptr->len, 1);

    if (wr_err == ERR_OK)
    {
      u16_t plen;
      u8_t freed;

      plen = ptr->len;

      /* continue with next pbuf in chain (if any) */
      es->p = ptr->next;

      if(es->p != NULL)
      {
        /* increment reference count for es->p */
        pbuf_ref(es->p);
      }

     /* chop first pbuf from chain */
      do
      {
        /* try hard to free pbuf */
        freed = pbuf_free(ptr);
      }
      while(freed == 0);
     /* we can read more data now */
     tcp_recved(tpcb, plen);
   }
   else if(wr_err == ERR_MEM)
   {
      /* we are low on memory, try later / harder, defer to poll */
     es->p = ptr;
   }
   else
   {
     /* other problem ?? */
   }
  }
}

static void tcp_server_connection_close(struct tcp_pcb *tpcb, struct tcp_server_struct *es)
{

  /* remove all callbacks */
  tcp_arg(tpcb, NULL);
  tcp_sent(tpcb, NULL);
  tcp_recv(tpcb, NULL);
  tcp_err(tpcb, NULL);
  tcp_poll(tpcb, NULL, 0);

  /* delete es structure */
  if (es != NULL)
  {
    mem_free(es);
  }

  /* close tcp connection */
  tcp_close(tpcb);
}

/* Handle the incoming TCP Data */

static void tcp_server_handle (struct tcp_pcb *tpcb, struct tcp_server_struct *es)
{
	//memset(buf_rx, '\0', SIZE_BUFFER);
	//strncpy(buf_rx, (char *)es->p->payload, es->p->tot_len);
	strncpy(buf_rx, (char *)es->p->payload, sizeof(buf_rx));

	HAL_GPIO_TogglePin(GPIOB, GPIO_PIN_7);

	//memset(buf_tx, '\0', SIZE_BUFFER);

	if (buf_rx[0] == '1') {
		snprintf(buf_tx, sizeof(buf_tx), "The buf_rx: %s\n", buf_rx);
		button_state = 1;
	}
	else
	{
		snprintf(buf_tx, sizeof(buf_tx), "AAAAAA\n");
		button_state = 0;
	}

	// allocate pbuf
	es->p = pbuf_alloc(PBUF_TRANSPORT, sizeof(buf_tx), PBUF_POOL);
	if (es->p != NULL) {
		// Copy data to pbuf
		pbuf_take(es->p, (char*)buf_tx, sizeof(buf_tx));
		tcp_server_send(tpcb, es);
		pbuf_free(es->p);
	} else {
		// Handle pbuf allocation error
		printf("pbuf_alloc failed\n");
	}
}

Thank you for your help

[STea]

Hello @Dreamer3D ,

could you please refer to the implementation of the Projects/STM324x9I_EVAL/Applications/LwIP/LwIP_TCP_Echo_Server which can be found from Gtihub .

as this is the proper way to implement a LWIP server on STM32 also you can refer to  AN3966 UM1713 for more details. 
Regards