STM32 Ethernet Sever

void udpServer_init(void)
{
	// UDP Control Block structure
   struct udp_pcb *upcb;
   err_t err;

   /* 1. Create a new UDP control block  */
   upcb = udp_new();

   /* 2. Bind the upcb to the local port */
   ip_addr_t myIPADDR;
   IP_ADDR4(&myIPADDR, 192, 168, 0, 111);

   err = udp_bind(upcb, &myIPADDR, 7);  // 7 is the server UDP port


   /* 3. Set a receive callback for the upcb */
   if(err == ERR_OK)
   {
	   udp_recv(upcb, udp_receive_callback, NULL);
   }
   else
   {
	   udp_remove(upcb);
   }
}

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, 192, 168, 0, 111);
	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);
	}
}

void udp_receive_callback(void *arg, struct udp_pcb *upcb, struct pbuf *p, const ip_addr_t *addr, u16_t port)
{
	struct pbuf *txBuf;

	/* Get the IP of the Client */
	char *remoteIP = ipaddr_ntoa(addr);

	char buf[100];


	int len = sprintf (buf,"Hello %s From UDP SERVER\n", (char*)p->payload);

	/* allocate pbuf from RAM*/
	txBuf = pbuf_alloc(PBUF_TRANSPORT,len, PBUF_RAM);

	/* copy the data into the buffer  */
	pbuf_take(txBuf, buf, len);

	/* Connect to the remote client */
	udp_connect(upcb, addr, port);

	/* Send a Reply to the Client */
	udp_send(upcb, txBuf);

	/* free the UDP connection, so we can accept new clients */
	udp_disconnect(upcb);

	/* Free the p_tx buffer */
	pbuf_free(txBuf);

	/* Free the p buffer */
	pbuf_free(p);
}

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

  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);

    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;
}

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

	/* get the Remote IP */
	ip4_addr_t inIP = tpcb->remote_ip;
	uint16_t inPort = tpcb->remote_port;

	/* Extract the IP */
	char *remIP = ipaddr_ntoa(&inIP);

	esTx->state = es->state;
	esTx->pcb = es->pcb;
	esTx->p = es->p;

	char buf[100];
	memset (buf, '\0', 100);

	strncpy(buf, (char *)es->p->payload, es->p->tot_len);
	strcat (buf, "+ Hello from TCP SERVER\n");


	esTx->p->payload = (void *)buf;
	esTx->p->tot_len = (es->p->tot_len - es->p->len) + strlen (buf);
	esTx->p->len = strlen (buf);

	tcp_server_send(tpcb, esTx);

	pbuf_free(es->p);

}