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/**

 * @file

 * Ethernet Interface Skeleton

 *

 */

/*

 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.

 * 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.

 *

 * This file is part of the lwIP TCP/IP stack.

 *

 * Author: Adam Dunkels <adam@sics.se>

 *

 */

/*

 * This file is a skeleton for developing Ethernet network interface

 * drivers for lwIP. Add code to the low_level functions and do a

 * search-and-replace for the word "ethernetif" to replace it with

 * something that better describes your network interface.

 */

#include "lwip/opt.h"

#if 0 /* don't build, this is only a skeleton, see previous comment */

#include "lwip/def.h"

#include "lwip/mem.h"

#include "lwip/pbuf.h"

#include "lwip/sys.h"

#include <lwip/stats.h>

#include <lwip/snmp.h>

#include "netif/etharp.h"

#include "netif/ppp_oe.h"

/* Define those to better describe your network interface. */

#define IFNAME0 'e'

#define IFNAME1 'n'

/**

 * Helper struct to hold private data used to operate your ethernet interface.

 * Keeping the ethernet address of the MAC in this struct is not necessary

 * as it is already kept in the struct netif.

 * But this is only an example, anyway...

 */

struct ethernetif {

  struct eth_addr *ethaddr;

  /* Add whatever per-interface state that is needed here. */

};

/* Forward declarations. */

static void  ethernetif_input(struct netif *netif);

/**

 * In this function, the hardware should be initialized.

 * Called from ethernetif_init().

 *

 * @param netif the already initialized lwip network interface structure

 *        for this ethernetif

 */

static void

low_level_init(struct netif *netif)

{

  struct ethernetif *ethernetif = netif->state;

  /* set MAC hardware address length */

  netif->hwaddr_len = ETHARP_HWADDR_LEN;

  /* set MAC hardware address */

  netif->hwaddr[0] = ;

  ...

  netif->hwaddr[5] = ;

  /* maximum transfer unit */

  netif->mtu = 1500;

  /* device capabilities */

  /* don't set NETIF_FLAG_ETHARP if this device is not an ethernet one */

  netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP | NETIF_FLAG_LINK_UP;

  /* Do whatever else is needed to initialize interface. */

}

/**

 * This function should do the actual transmission of the packet. The packet is

 * contained in the pbuf that is passed to the function. This pbuf

 * might be chained.

 *

 * @param netif the lwip network interface structure for this ethernetif

 * @param p the MAC packet to send (e.g. IP packet including MAC addresses and type)

 * @return ERR_OK if the packet could be sent

 *         an err_t value if the packet couldn't be sent

 *

 * @note Returning ERR_MEM here if a DMA queue of your MAC is full can lead to

 *       strange results. You might consider waiting for space in the DMA queue

 *       to become availale since the stack doesn't retry to send a packet

 *       dropped because of memory failure (except for the TCP timers).

 */

static err_t

low_level_output(struct netif *netif, struct pbuf *p)

{

  struct ethernetif *ethernetif = netif->state;

  struct pbuf *q;

  initiate transfer();

#if ETH_PAD_SIZE

  pbuf_header(p, -ETH_PAD_SIZE); /* drop the padding word */

#endif

  for(q = p; q != NULL; q = q->next) {

    /* Send the data from the pbuf to the interface, one pbuf at a

       time. The size of the data in each pbuf is kept in the ->len

       variable. */

    send data from(q->payload, q->len);

  }

  signal that packet should be sent();

#if ETH_PAD_SIZE

  pbuf_header(p, ETH_PAD_SIZE); /* reclaim the padding word */

#endif

  LINK_STATS_INC(link.xmit);

  return ERR_OK;

}

/**

 * Should allocate a pbuf and transfer the bytes of the incoming

 * packet from the interface into the pbuf.

 *

 * @param netif the lwip network interface structure for this ethernetif

 * @return a pbuf filled with the received packet (including MAC header)

 *         NULL on memory error

 */

static struct pbuf *

low_level_input(struct netif *netif)

{

  struct ethernetif *ethernetif = netif->state;

  struct pbuf *p, *q;

  u16_t len;

  /* Obtain the size of the packet and put it into the "len"

     variable. */

  len = ;

#if ETH_PAD_SIZE

  len += ETH_PAD_SIZE; /* allow room for Ethernet padding */

#endif

  /* We allocate a pbuf chain of pbufs from the pool. */

  p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);

  if (p != NULL) {

#if ETH_PAD_SIZE

    pbuf_header(p, -ETH_PAD_SIZE); /* drop the padding word */

#endif

    /* We iterate over the pbuf chain until we have read the entire

     * packet into the pbuf. */

    for(q = p; q != NULL; q = q->next) {

      /* Read enough bytes to fill this pbuf in the chain. The

       * available data in the pbuf is given by the q->len

       * variable.

       * This does not necessarily have to be a memcpy, you can also preallocate

       * pbufs for a DMA-enabled MAC and after receiving truncate it to the

       * actually received size. In this case, ensure the tot_len member of the

       * pbuf is the sum of the chained pbuf len members.

       */

      read data into(q->payload, q->len);

    }

    acknowledge that packet has been read();

#if ETH_PAD_SIZE

    pbuf_header(p, ETH_PAD_SIZE); /* reclaim the padding word */

#endif

    LINK_STATS_INC(link.recv);

  } else {

    drop packet();

    LINK_STATS_INC(link.memerr);

    LINK_STATS_INC(link.drop);

  }

  return p;

}

/**

 * This function should be called when a packet is ready to be read

 * from the interface. It uses the function low_level_input() that

 * should handle the actual reception of bytes from the network

 * interface. Then the type of the received packet is determined and

 * the appropriate input function is called.

 *

 * @param netif the lwip network interface structure for this ethernetif

 */

static void

ethernetif_input(struct netif *netif)

{

  struct ethernetif *ethernetif;

  struct eth_hdr *ethhdr;

  struct pbuf *p;

  ethernetif = netif->state;

  /* move received packet into a new pbuf */

  p = low_level_input(netif);

  /* no packet could be read, silently ignore this */

  if (p == NULL) return;

  /* points to packet payload, which starts with an Ethernet header */

  ethhdr = p->payload;

  switch (htons(ethhdr->type)) {

  /* IP or ARP packet? */

  case ETHTYPE_IP:

  case ETHTYPE_ARP:

#if PPPOE_SUPPORT

  /* PPPoE packet? */

  case ETHTYPE_PPPOEDISC:

  case ETHTYPE_PPPOE:

#endif /* PPPOE_SUPPORT */

    /* full packet send to tcpip_thread to process */

    if (netif->input(p, netif)!=ERR_OK)

     { LWIP_DEBUGF(NETIF_DEBUG, ("ethernetif_input: IP input error\n"));

       pbuf_free(p);

       p = NULL;

     }

    break;

  default:

    pbuf_free(p);

    p = NULL;

    break;

  }

}

/**

 * Should be called at the beginning of the program to set up the

 * network interface. It calls the function low_level_init() to do the

 * actual setup of the hardware.

 *

 * This function should be passed as a parameter to netif_add().

 *

 * @param netif the lwip network interface structure for this ethernetif

 * @return ERR_OK if the loopif is initialized

 *         ERR_MEM if private data couldn't be allocated

 *         any other err_t on error

 */

err_t

ethernetif_init(struct netif *netif)

{

  struct ethernetif *ethernetif;

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

  ethernetif = mem_malloc(sizeof(struct ethernetif));

  if (ethernetif == NULL) {

    LWIP_DEBUGF(NETIF_DEBUG, ("ethernetif_init: out of memory\n"));

    return ERR_MEM;

  }

#if LWIP_NETIF_HOSTNAME

  /* Initialize interface hostname */

  netif->hostname = "lwip";

#endif /* LWIP_NETIF_HOSTNAME */

  /*

   * Initialize the snmp variables and counters inside the struct netif.

   * The last argument should be replaced with your link speed, in units

   * of bits per second.

   */

  NETIF_INIT_SNMP(netif, snmp_ifType_ethernet_csmacd, LINK_SPEED_OF_YOUR_NETIF_IN_BPS);

  netif->state = ethernetif;

  netif->name[0] = IFNAME0;

  netif->name[1] = IFNAME1;

  /* We directly use etharp_output() here to save a function call.

   * You can instead declare your own function an call etharp_output()

   * from it if you have to do some checks before sending (e.g. if link

   * is available...) */

  netif->output = etharp_output;

  netif->linkoutput = low_level_output;

  ethernetif->ethaddr = (struct eth_addr *)&(netif->hwaddr[0]);

  /* initialize the hardware */

  low_level_init(netif);

  return ERR_OK;

}

#endif /* 0 */