/**
  ******************************************************************************
  * @file    LwIP/LwIP_UDP_Echo_Server/Src/udp_echoserver.c
  * @author  MCD Application Team
  * @version V1.6.0
  * @date    12-May-2017
  * @brief   UDP echo server
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; Copyright © 2016 STMicroelectronics International N.V. 
  * All rights reserved.</center></h2>
  *
  * Redistribution and use in source and binary forms, with or without 
  * modification, are permitted, provided that the following conditions are met:
  *
  * 1. Redistribution of source code must retain the above copyright notice, 
  *    this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright notice,
  *    this list of conditions and the following disclaimer in the documentation
  *    and/or other materials provided with the distribution.
  * 3. Neither the name of STMicroelectronics nor the names of other 
  *    contributors to this software may be used to endorse or promote products 
  *    derived from this software without specific written permission.
  * 4. This software, including modifications and/or derivative works of this 
  *    software, must execute solely and exclusively on microcontroller or
  *    microprocessor devices manufactured by or for STMicroelectronics.
  * 5. Redistribution and use of this software other than as permitted under 
  *    this license is void and will automatically terminate your rights under 
  *    this license. 
  *
  * THIS SOFTWARE IS PROVIDED BY STMICROELECTRONICS AND CONTRIBUTORS "AS IS" 
  * AND ANY EXPRESS, IMPLIED OR STATUTORY WARRANTIES, INCLUDING, BUT NOT 
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A 
  * PARTICULAR PURPOSE AND NON-INFRINGEMENT OF THIRD PARTY INTELLECTUAL PROPERTY
  * RIGHTS ARE DISCLAIMED TO THE FULLEST EXTENT PERMITTED BY LAW. IN NO EVENT 
  * SHALL STMICROELECTRONICS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, 
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  * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  ******************************************************************************
  */

/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "lwip/pbuf.h"
#include "lwip/udp.h"
#include "lwip/tcp.h"
#include <string.h>
#include <stdio.h>

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
#define UDP_SERVER_PORT    7   /* define the UDP local connection port */
#define UDP_CLIENT_PORT    7   /* define the UDP remote connection port */

/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* Private function prototypes -----------------------------------------------*/
void udp_echoserver_receive_callback(void *arg, struct udp_pcb *upcb, struct pbuf *p, const ip_addr_t *addr, u16_t port);

/* Private functions ---------------------------------------------------------*/

/**
  * @brief  Initialize the server application.
  * @param  None
  * @retval None
  */
void udp_echoserver_init(void)
{
   struct udp_pcb *upcb;
   err_t err;
   
   /* Create a new UDP control block  */
   upcb = udp_new();
   
   if (upcb)
   {
     /* Bind the upcb to the UDP_PORT port */
     /* Using IP_ADDR_ANY allow the upcb to be used by any local interface */
      err = udp_bind(upcb, IP_ADDR_ANY, UDP_SERVER_PORT);
      
      if(err == ERR_OK)
      {
        /* Set a receive callback for the upcb */
        udp_recv(upcb, udp_echoserver_receive_callback, NULL);
      }
   }
}

/**
  * @brief This function is called when an UDP datagrm has been received on the port UDP_PORT.
  * @param arg user supplied argument (udp_pcb.recv_arg)
  * @param pcb the udp_pcb which received data
  * @param p the packet buffer that was received
  * @param addr the remote IP address from which the packet was received
  * @param port the remote port from which the packet was received
  * @retval None
  */
void udp_echoserver_receive_callback(void *arg, struct udp_pcb *upcb, struct pbuf *p, const ip_addr_t *addr, u16_t port)
{

  /* Connect to the remote client */
  udp_connect(upcb, addr, UDP_CLIENT_PORT);
    
  /* Tell the client that we have accepted it */
  udp_send(upcb, p);

  /* free the UDP connection, so we can accept new clients */
  udp_disconnect(upcb);
	
  /* Free the p buffer */
  pbuf_free(p);
   
}

/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
