nuttx/net/pkt/pkt_input.c

/****************************************************************************
 * net/pkt/pkt_input.c
 * Handling incoming packet input
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

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

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

#include <errno.h>
#include <debug.h>

#include <nuttx/mm/iob.h>
#include <nuttx/net/netdev.h>
#include <nuttx/net/pkt.h>

#include "devif/devif.h"
#include "pkt/pkt.h"

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

/****************************************************************************
 * Name: pkt_datahandler
 *
 * Description:
 *   Handle packet that are not accepted by the application.
 *
 * Input Parameters:
 *   dev    - Device instance only the input packet in d_buf, length = d_len;
 *   conn   - A pointer to the PKT connection structure
 *
 * Returned Value:
 *   The number of bytes actually buffered is returned.  This will be either
 *   zero or equal to buflen; partial packets are not buffered.
 *
 ****************************************************************************/

static uint16_t pkt_datahandler(FAR struct net_driver_s *dev,
                                FAR struct pkt_conn_s *conn)
{
  FAR struct iob_s *iob = iob_tryalloc(true);
  int ret;

  if (iob == NULL)
    {
      return 0;
    }

  /* Clone an I/O buffer chain of the L2 data, use throttled IOB to avoid
   * overconsumption.
   * TODO: Optimize IOB clone after we support shared IOB.
   */

  ret = iob_clone_partial(dev->d_iob, dev->d_len, -NET_LL_HDRLEN(dev),
                          iob, 0, true, false);
  if (ret < 0)
    {
      nerr("ERROR: Failed to clone the I/O buffer chain: %d\n", ret);
      goto errout;
    }

  /* Add the new I/O buffer chain to the tail of the read-ahead queue (again
   * without waiting).
   */

  if ((ret = iob_tryadd_queue(iob, &conn->readahead)) < 0)
    {
      nerr("ERROR: Failed to queue the I/O buffer chain: %d\n", ret);
      goto errout;
    }
  else
    {
      ninfo("Buffered %d bytes\n", dev->d_len);
      return dev->d_len;
    }

errout:
  iob_free_chain(iob);
  return 0;
}

/****************************************************************************
 * Name: pkt_in
 *
 * Description:
 *   Handle incoming packet input
 *
 *   This is the iob buffer version of pkt_input(),
 *   this function will support send/receive iob vectors directly between
 *   the driver and l3/l4 stack to avoid unnecessary memory copies,
 *   especially on hardware that supports Scatter/gather, which can
 *   greatly improve performance
 *   this function will uses d_iob as packets input which used by some
 *   NICs such as celluler net driver.
 *
 * Input Parameters:
 *   dev - The device driver structure containing the received packet
 *
 * Returned Value:
 *   OK     The packet has been processed  and can be deleted
 *  -EAGAIN There is a matching connection, but could not dispatch the packet
 *          yet.  Useful when a packet arrives before a recv call is in
 *          place.
 *
 * Assumptions:
 *   The network is locked.
 *
 ****************************************************************************/

static int pkt_in(FAR struct net_driver_s *dev)
{
  FAR struct pkt_conn_s *conn;
  FAR struct eth_hdr_s  *pbuf = ETHBUF;
  int ret = OK;

  conn = pkt_active(pbuf);
  if (conn)
    {
      uint16_t flags;

      /* Setup for the application callback */

      dev->d_appdata = dev->d_buf;
      dev->d_sndlen  = 0;

      /* Perform the application callback */

      flags = pkt_callback(dev, conn, PKT_NEWDATA);

      /* If the operation was successful, the PKT_NEWDATA flag is removed
       * and thus the packet can be deleted (OK will be returned).
       */

      if ((flags & PKT_NEWDATA) != 0)
        {
          /* Add the PKT to the socket read-ahead buffer. */

          if (pkt_datahandler(dev, conn) == 0)
            {
              /* No.. the packet was not processed now.  Return -EAGAIN so
               * that the driver may retry again later.
               */

              nwarn("WARNING: Packet not processed\n");
              ret = -EAGAIN;
            }
        }
    }
  else
    {
      ninfo("No PKT listener\n");
    }

  return ret;
}

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

/****************************************************************************
 * Name: pkt_input
 *
 * Description:
 *   Handle incoming packet input
 *
 * Input Parameters:
 *   dev - The device driver structure containing the received packet
 *
 * Returned Value:
 *   OK     The packet has been processed  and can be deleted
 *  -EAGAIN There is a matching connection, but could not dispatch the packet
 *          yet.  Useful when a packet arrives before a recv call is in
 *          place.
 *
 * Assumptions:
 *   The network is locked.
 *
 ****************************************************************************/

int pkt_input(FAR struct net_driver_s *dev)
{
  FAR uint8_t *buf;
  int ret;

  if (dev->d_iob != NULL)
    {
      buf = dev->d_buf;

      /* Set the device buffer to l2 */

      dev->d_buf = NETLLBUF;
      ret = pkt_in(dev);

      dev->d_buf = buf;

      return ret;
    }

  return netdev_input(dev, pkt_in, false);
}

#endif /* CONFIG_NET && CONFIG_NET_PKT */