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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>

 *

 */

/* ip.c

 *

 * This is the code for the IP layer for IPv6.

 *

 */

#include "lwip/opt.h"

#include "lwip/def.h"

#include "lwip/mem.h"

#include "lwip/ip.h"

#include "lwip/inet.h"

#include "lwip/netif.h"

#include "lwip/icmp.h"

#include "lwip/udp.h"

#include "lwip/tcp.h"

#include "lwip/stats.h"

#include "arch/perf.h"

/* ip_init:

 *

 * Initializes the IP layer.

 */

void

ip_init(void)

{

}

/* ip_route:

 *

 * Finds the appropriate network interface for a given IP address. It searches the

 * list of network interfaces linearly. A match is found if the masked IP address of

 * the network interface equals the masked IP address given to the function.

 */

struct netif *

ip_route(struct ip_addr *dest)

{

  struct netif *netif;

  for(netif = netif_list; netif != NULL; netif = netif->next) {

    if (ip_addr_netcmp(dest, &(netif->ip_addr), &(netif->netmask))) {

      return netif;

    }

  }

  return netif_default;

}

/* ip_forward:

 *

 * Forwards an IP packet. It finds an appropriate route for the packet, decrements

 * the TTL value of the packet, adjusts the checksum and outputs the packet on the

 * appropriate interface.

 */

static void

ip_forward(struct pbuf *p, struct ip_hdr *iphdr)

{

  struct netif *netif;

  PERF_START;

  if ((netif = ip_route((struct ip_addr *)&(iphdr->dest))) == NULL) {

    LWIP_DEBUGF(IP_DEBUG, ("ip_input: no forwarding route found for "));

#if IP_DEBUG

    ip_addr_debug_print(IP_DEBUG, ((struct ip_addr *)&(iphdr->dest)));

#endif /* IP_DEBUG */

    LWIP_DEBUGF(IP_DEBUG, ("\n"));

    pbuf_free(p);

    return;

  }

  /* Decrement TTL and send ICMP if ttl == 0. */

  if (--iphdr->hoplim == 0) {

#if LWIP_ICMP

    /* Don't send ICMP messages in response to ICMP messages */

    if (iphdr->nexthdr != IP_PROTO_ICMP) {

      icmp_time_exceeded(p, ICMP_TE_TTL);

    }

#endif /* LWIP_ICMP */

    pbuf_free(p);

    return;

  }

  /* Incremental update of the IP checksum. */

  /*  if (iphdr->chksum >= htons(0xffff - 0x100)) {

    iphdr->chksum += htons(0x100) + 1;

  } else {

    iphdr->chksum += htons(0x100);

    }*/

  LWIP_DEBUGF(IP_DEBUG, ("ip_forward: forwarding packet to "));

#if IP_DEBUG

  ip_addr_debug_print(IP_DEBUG, ((struct ip_addr *)&(iphdr->dest)));

#endif /* IP_DEBUG */

  LWIP_DEBUGF(IP_DEBUG, ("\n"));

  IP_STATS_INC(ip.fw);

  IP_STATS_INC(ip.xmit);

  PERF_STOP("ip_forward");

  netif->output(netif, p, (struct ip_addr *)&(iphdr->dest));

}

/* ip_input:

 *

 * This function is called by the network interface device driver when an IP packet is

 * received. The function does the basic checks of the IP header such as packet size

 * being at least larger than the header size etc. If the packet was not destined for

 * us, the packet is forwarded (using ip_forward). The IP checksum is always checked.

 *

 * Finally, the packet is sent to the upper layer protocol input function.

 */

void

ip_input(struct pbuf *p, struct netif *inp) {

  struct ip_hdr *iphdr;

  struct netif *netif;

  PERF_START;

#if IP_DEBUG

  ip_debug_print(p);

#endif /* IP_DEBUG */

  IP_STATS_INC(ip.recv);

  /* identify the IP header */

  iphdr = p->payload;

  if (iphdr->v != 6) {

    LWIP_DEBUGF(IP_DEBUG, ("IP packet dropped due to bad version number\n"));

#if IP_DEBUG

    ip_debug_print(p);

#endif /* IP_DEBUG */

    pbuf_free(p);

    IP_STATS_INC(ip.err);

    IP_STATS_INC(ip.drop);

    return;

  }

  /* is this packet for us? */

  for(netif = netif_list; netif != NULL; netif = netif->next) {

#if IP_DEBUG

    LWIP_DEBUGF(IP_DEBUG, ("ip_input: iphdr->dest "));

    ip_addr_debug_print(IP_DEBUG, ((struct ip_addr *)&(iphdr->dest)));

    LWIP_DEBUGF(IP_DEBUG, ("netif->ip_addr "));

    ip_addr_debug_print(IP_DEBUG, ((struct ip_addr *)&(iphdr->dest)));

    LWIP_DEBUGF(IP_DEBUG, ("\n"));

#endif /* IP_DEBUG */

    if (ip_addr_cmp(&(iphdr->dest), &(netif->ip_addr))) {

      break;

    }

  }

  if (netif == NULL) {

    /* packet not for us, route or discard */

#if IP_FORWARD

    ip_forward(p, iphdr);

#endif

    pbuf_free(p);

    return;

  }

  pbuf_realloc(p, IP_HLEN + ntohs(iphdr->len));

  /* send to upper layers */

#if IP_DEBUG

  /*  LWIP_DEBUGF("ip_input: \n");

  ip_debug_print(p);

  LWIP_DEBUGF("ip_input: p->len %"U16_F" p->tot_len %"U16_F"\n", p->len, p->tot_len);*/

#endif /* IP_DEBUG */

  if(pbuf_header(p, -IP_HLEN)) {

    LWIP_ASSERT("Can't move over header in packet", 0);

    return;

  }

  switch (iphdr->nexthdr) {

  case IP_PROTO_UDP:

    udp_input(p, inp);

    break;

  case IP_PROTO_TCP:

    tcp_input(p, inp);

    break;

#if LWIP_ICMP

  case IP_PROTO_ICMP:

    icmp_input(p, inp);

    break;

#endif /* LWIP_ICMP */

  default:

#if LWIP_ICMP

    /* send ICMP destination protocol unreachable */

    icmp_dest_unreach(p, ICMP_DUR_PROTO);

#endif /* LWIP_ICMP */

    pbuf_free(p);

    LWIP_DEBUGF(IP_DEBUG, ("Unsupported transport protocol %"U16_F"\n",

          iphdr->nexthdr));

    IP_STATS_INC(ip.proterr);

    IP_STATS_INC(ip.drop);

  }

  PERF_STOP("ip_input");

}

/* ip_output_if:

 *

 * Sends an IP packet on a network interface. This function constructs the IP header

 * and calculates the IP header checksum. If the source IP address is NULL,

 * the IP address of the outgoing network interface is filled in as source address.

 */

err_t

ip_output_if (struct pbuf *p, struct ip_addr *src, struct ip_addr *dest,

       u8_t ttl,

       u8_t proto, struct netif *netif)

{

  struct ip_hdr *iphdr;

  PERF_START;

  LWIP_DEBUGF(IP_DEBUG, ("len %"U16_F" tot_len %"U16_F"\n", p->len, p->tot_len));

  if (pbuf_header(p, IP_HLEN)) {

    LWIP_DEBUGF(IP_DEBUG, ("ip_output: not enough room for IP header in pbuf\n"));

    IP_STATS_INC(ip.err);

    return ERR_BUF;

  }

  LWIP_DEBUGF(IP_DEBUG, ("len %"U16_F" tot_len %"U16_F"\n", p->len, p->tot_len));

  iphdr = p->payload;

  if (dest != IP_HDRINCL) {

    LWIP_DEBUGF(IP_DEBUG, ("!IP_HDRLINCL\n"));

    iphdr->hoplim = ttl;

    iphdr->nexthdr = proto;

    iphdr->len = htons(p->tot_len - IP_HLEN);

    ip_addr_set(&(iphdr->dest), dest);

    iphdr->v = 6;

    if (ip_addr_isany(src)) {

      ip_addr_set(&(iphdr->src), &(netif->ip_addr));

    } else {

      ip_addr_set(&(iphdr->src), src);

    }

  } else {

    dest = &(iphdr->dest);

  }

  IP_STATS_INC(ip.xmit);

  LWIP_DEBUGF(IP_DEBUG, ("ip_output_if: %c%c (len %"U16_F")\n", netif->name[0], netif->name[1], p->tot_len));

#if IP_DEBUG

  ip_debug_print(p);

#endif /* IP_DEBUG */

  PERF_STOP("ip_output_if");

  return netif->output(netif, p, dest);

}

/* ip_output:

 *

 * Simple interface to ip_output_if. It finds the outgoing network interface and

 * calls upon ip_output_if to do the actual work.

 */

err_t

ip_output(struct pbuf *p, struct ip_addr *src, struct ip_addr *dest,

    u8_t ttl, u8_t proto)

{

  struct netif *netif;

  if ((netif = ip_route(dest)) == NULL) {

    LWIP_DEBUGF(IP_DEBUG, ("ip_output: No route to 0x%"X32_F"\n", dest->addr));

    IP_STATS_INC(ip.rterr);

    return ERR_RTE;

  }

  return ip_output_if (p, src, dest, ttl, proto, netif);

}

#if LWIP_NETIF_HWADDRHINT

err_t

ip_output_hinted(struct pbuf *p, struct ip_addr *src, struct ip_addr *dest,

          u8_t ttl, u8_t tos, u8_t proto, u8_t *addr_hint)

{

  struct netif *netif;

  err_t err;

  if ((netif = ip_route(dest)) == NULL) {

    LWIP_DEBUGF(IP_DEBUG, ("ip_output: No route to 0x%"X32_F"\n", dest->addr));

    IP_STATS_INC(ip.rterr);

    return ERR_RTE;

  }

  netif->addr_hint = addr_hint;

  err = ip_output_if(p, src, dest, ttl, tos, proto, netif);

  netif->addr_hint = NULL;

  return err;

}

#endif /* LWIP_NETIF_HWADDRHINT*/

#if IP_DEBUG

void

ip_debug_print(struct pbuf *p)

{

  struct ip_hdr *iphdr = p->payload;

  LWIP_DEBUGF(IP_DEBUG, ("IP header:\n"));

  LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));

  LWIP_DEBUGF(IP_DEBUG, ("|%2"S16_F" |  %"X16_F"%"X16_F"  |      %"X16_F"%"X16_F"           | (v, traffic class, flow label)\n",

        iphdr->v,

        iphdr->tclass1, iphdr->tclass2,

        iphdr->flow1, iphdr->flow2));

  LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));

  LWIP_DEBUGF(IP_DEBUG, ("|    %5"U16_F"      | %2"U16_F"  |  %2"U16_F"   | (len, nexthdr, hoplim)\n",

        ntohs(iphdr->len),

        iphdr->nexthdr,

        iphdr->hoplim));

  LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));

  LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (src)\n",

        (ntohl(iphdr->src.addr[0]) >> 16) & 0xffff,

        ntohl(iphdr->src.addr[0]) & 0xffff));

  LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (src)\n",

        (ntohl(iphdr->src.addr[1]) >> 16) & 0xffff,

        ntohl(iphdr->src.addr[1]) & 0xffff));

  LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (src)\n",

        (ntohl(iphdr->src.addr[2]) >> 16) & 0xffff,

        ntohl(iphdr->src.addr[2]) & 0xffff));

  LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (src)\n",

        (ntohl(iphdr->src.addr[3]) >> 16) & 0xffff,

        ntohl(iphdr->src.addr[3]) & 0xffff));

  LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));

  LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (dest)\n",

        (ntohl(iphdr->dest.addr[0]) >> 16) & 0xffff,

        ntohl(iphdr->dest.addr[0]) & 0xffff));

  LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (dest)\n",

        (ntohl(iphdr->dest.addr[1]) >> 16) & 0xffff,

        ntohl(iphdr->dest.addr[1]) & 0xffff));

  LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (dest)\n",

        (ntohl(iphdr->dest.addr[2]) >> 16) & 0xffff,

        ntohl(iphdr->dest.addr[2]) & 0xffff));

  LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (dest)\n",

        (ntohl(iphdr->dest.addr[3]) >> 16) & 0xffff,

        ntohl(iphdr->dest.addr[3]) & 0xffff));

  LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));

}

#endif /* IP_DEBUG */