uip-udpinput.c

這是一個實時嵌入式作業系統 實作了MCS51 ARM等MCU

/****************************************************************************
 * net/uip/uip-udpinput.c
 * Handling incoming UDP input
 *
 *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <[e-mail]>
 *
 * Adapted for NuttX from logic in uIP which also has a BSD-like license:
 *
 *   Original author Adam Dunkels <[e-mail]>
 *   Copyright () 2001-2003, Adam Dunkels.
 *   All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions 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. The name of the author may not be used to endorse or promote
 *    products derived from this software without specific prior
 *    written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR 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, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>
#if defined(CONFIG_NET) && defined(CONFIG_NET_UDP)

#include <sys/types.h>
#include <debug.h>

#include <net/uip/uipopt.h>
#include <net/uip/uip.h>
#include <net/uip/uip-arch.h>

#include "uip-internal.h"

/****************************************************************************
 * Definitions
 ****************************************************************************/

#define UDPBUF ((struct uip_udpip_hdr *)&dev->d_buf[UIP_LLH_LEN])

/****************************************************************************
 * Public Variables
 ****************************************************************************/

/****************************************************************************
 * Private Variables
 ****************************************************************************/

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: uip_udpinput
 *
 * Description:
 *   Handle incoming UDP input
 *
 * Parameters:
 *   dev - The device driver structure containing the received UDP packet
 *
 * Return:
 *   None
 *
 * Assumptions:
 *   Called from the interrupt level or with interrupts disabled.
 *
 ****************************************************************************/

void uip_udpinput(struct uip_driver_s *dev)
{
  struct uip_udp_conn *conn;

  /* UDP processing is really just a hack. We don't do anything to the UDP/IP
   * headers, but let the UDP application do all the hard work. If the
   * application sets d_sndlen, it has a packet to send.
   */

  dev->d_len    -= UIP_IPUDPH_LEN;
#ifdef CONFIG_NET_UDP_CHECKSUMS
  dev->d_appdata = &dev->d_buf[UIP_LLH_LEN + UIP_IPUDPH_LEN];
  if (UDPBUF->udpchksum != 0 && uip_udpchksum(dev) != 0xffff)
    {
#ifdef CONFIG_NET_STATISTICS
      uip_stat.udp.drop++;
      uip_stat.udp.chkerr++;
#endif
      ndbg("Bad UDP checksum\n");
      dev->d_len = 0;
    }
  else
#endif
    {
      /* Demultiplex this UDP packet between the UDP "connections". */

      conn = uip_udpactive(UDPBUF);
      if (conn)
        {
          /* Setup for the application callback */

          dev->d_appdata = &dev->d_buf[UIP_LLH_LEN + UIP_IPUDPH_LEN];
          dev->d_snddata = &dev->d_buf[UIP_LLH_LEN + UIP_IPUDPH_LEN];
          dev->d_sndlen  = 0;

          /* Perform the application callback */

          uip_udpcallback(dev, conn, UIP_NEWDATA);

          /* If the application has data to send, setup the UDP/IP header */

          if (dev->d_sndlen > 0)
            {
              uip_udpsend(dev, conn);
            }
        }
      else
        {
          ndbg("No listener on UDP port\n");
          dev->d_len = 0;
        }
    }

  return;
}

#endif /* CONFIG_NET && CONFIG_NET_UDP */