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/*

 * 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"

#include "lwip/def.h"

#include "lwip/mem.h"

#include "lwip/pbuf.h"

#include "lwip/sys.h"

#include <lwip/stats.h>

#include "netif/etharp.h"

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

#define IFNAME0 'e'

#define IFNAME1 'n'

struct ethernetif {

  struct eth_addr *ethaddr;

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

};

static const struct eth_addr ethbroadcast = {{0xff,0xff,0xff,0xff,0xff,0xff}};

/* Forward declarations. */

static void  ethernetif_input(struct netif *netif);

static err_t ethernetif_output(struct netif *netif, struct pbuf *p,

             struct ip_addr *ipaddr);

static void

low_level_init(struct netif *netif)

{

  struct ethernetif *ethernetif = netif->state;

  /* set MAC hardware address length */

  netif->hwaddr_len = 6;

  /* set MAC hardware address */

  netif->hwaddr[0] = ;

  ...

  netif->hwaddr[5] = ;

  /* maximum transfer unit */

  netif->mtu = 1500;

  /* broadcast capability */

  netif->flags = NETIF_FLAG_BROADCAST;

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

}

/*

 * low_level_output():

 *

 * 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.

 *

 */

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

#if LINK_STATS

  lwip_stats.link.xmit++;

#endif /* LINK_STATS */      

  return ERR_OK;

}

/*

 * low_level_input():

 *

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

 * packet from the interface into the pbuf.

 *

 */

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. */

      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

#if LINK_STATS

    lwip_stats.link.recv++;

#endif /* LINK_STATS */      

  } else {

    drop packet();

#if LINK_STATS

    lwip_stats.link.memerr++;

    lwip_stats.link.drop++;

#endif /* LINK_STATS */      

  }

  return p;

}

/*

 * ethernetif_output():

 *

 * This function is called by the TCP/IP stack when an IP packet

 * should be sent. It calls the function called low_level_output() to

 * do the actual transmission of the packet.

 *

 */

static err_t

ethernetif_output(struct netif *netif, struct pbuf *p,

      struct ip_addr *ipaddr)

{

 /* resolve hardware address, then send (or queue) packet */

  return etharp_output(netif, ipaddr, p);

}

/*

 * ethernetif_input():

 *

 * 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.

 *

 */

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;

#if LINK_STATS

  lwip_stats.link.recv++;

#endif /* LINK_STATS */

  ethhdr = p->payload;

  switch (htons(ethhdr->type)) {

  /* IP packet? */

  case ETHTYPE_IP:

    /* update ARP table */

    etharp_ip_input(netif, p);

    /* skip Ethernet header */

    pbuf_header(p, -sizeof(struct eth_hdr));

    /* pass to network layer */

    netif->input(p, netif);

    break;

    case ETHTYPE_ARP:

      /* pass p to ARP module  */

      etharp_arp_input(netif, ethernetif->ethaddr, p);

      break;

    default:

      pbuf_free(p);

      p = NULL;

      break;

  }

}

static void

arp_timer(void *arg)

{

  etharp_tmr();

  sys_timeout(ARP_TMR_INTERVAL, arp_timer, NULL);

}

/*

 * ethernetif_init():

 *

 * 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.

 *

 */

err_t

ethernetif_init(struct netif *netif)

{

  struct ethernetif *ethernetif;

  ethernetif = mem_malloc(sizeof(struct ethernetif));

  if (ethernetif == NULL)

  {

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

        return ERR_MEM;

  }

  netif->state = ethernetif;

  netif->name[0] = IFNAME0;

  netif->name[1] = IFNAME1;

  netif->output = ethernetif_output;

  netif->linkoutput = low_level_output;

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

  low_level_init(netif);

  etharp_init();

  sys_timeout(ARP_TMR_INTERVAL, arp_timer, NULL);

  return ERR_OK;

}