[Gc-linux-cvs] ipl/lwip/core/ipv4 icmp.c,NONE,1.1 ip.c,NONE,1.1 ip_addr.c,NONE,1.1 ip_frag.c,NONE,1.1

[<rob...@us...>]

Update of /cvsroot/gc-linux/ipl/lwip/core/ipv4
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv24322

Added Files:
	icmp.c ip.c ip_addr.c ip_frag.c 
Log Message:
adding lwip/ipv4


--- NEW FILE: icmp.c ---
/*
 * 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 <ad...@si...>
 *
 */

/* Some ICMP messages should be passed to the transport protocols. This
   is not implemented. */

#include "lwip/opt.h"

#include "lwip/icmp.h"
#include "lwip/inet.h"
#include "lwip/ip.h"
#include "lwip/def.h"

#include "lwip/stats.h"

#include "lwip/snmp.h"

void
icmp_input(struct pbuf *p, struct netif *inp)
{
  unsigned char type;
  unsigned char code;
  struct icmp_echo_hdr *iecho;
  struct ip_hdr *iphdr;
  struct ip_addr tmpaddr;
  u16_t hlen;

  ICMP_STATS_INC(icmp.recv);
  snmp_inc_icmpinmsgs();


  iphdr = p->payload;
  hlen = IPH_HL(iphdr) * 4;
  if (pbuf_header(p, -((s16_t)hlen)) || (p->tot_len < sizeof(u16_t)*2)) {
    LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: short ICMP (%u bytes) received\n", p->tot_len));
    pbuf_free(p);
    ICMP_STATS_INC(icmp.lenerr);
    snmp_inc_icmpinerrors();
    return;
  }

  type = *((u8_t *)p->payload);
  code = *(((u8_t *)p->payload)+1);
  switch (type) {
  case ICMP_ECHO:
    if (ip_addr_isbroadcast(&iphdr->dest, &inp->netmask) ||
       ip_addr_ismulticast(&iphdr->dest)) {
      LWIP_DEBUGF(ICMP_DEBUG, ("Smurf.\n"));
      ICMP_STATS_INC(icmp.err);
      pbuf_free(p);
      return;
    }
    LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ping\n"));
    if (p->tot_len < sizeof(struct icmp_echo_hdr)) {
      LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: bad ICMP echo received\n"));
      pbuf_free(p);
      ICMP_STATS_INC(icmp.lenerr);
      snmp_inc_icmpinerrors();

      return;
    }
    iecho = p->payload;
    if (inet_chksum_pbuf(p) != 0) {
      LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: checksum failed for received ICMP echo\n"));
      pbuf_free(p);
      ICMP_STATS_INC(icmp.chkerr);
      snmp_inc_icmpinerrors();
      return;
    }
    tmpaddr.addr = iphdr->src.addr;
    iphdr->src.addr = iphdr->dest.addr;
    iphdr->dest.addr = tmpaddr.addr;
    ICMPH_TYPE_SET(iecho, ICMP_ER);
    /* adjust the checksum */
    if (iecho->chksum >= htons(0xffff - (ICMP_ECHO << 8))) {
      iecho->chksum += htons(ICMP_ECHO << 8) + 1;
    } else {
      iecho->chksum += htons(ICMP_ECHO << 8);
    }
    ICMP_STATS_INC(icmp.xmit);
    /* increase number of messages attempted to send */
    snmp_inc_icmpoutmsgs();
    /* increase number of echo replies attempted to send */
    snmp_inc_icmpoutechoreps();

    pbuf_header(p, hlen);
    ip_output_if(p, &(iphdr->src), IP_HDRINCL,
		 IPH_TTL(iphdr), 0, IP_PROTO_ICMP, inp);
    break;
  default:
  LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ICMP type %d code %d not supported.\n", (int)type, (int)code));
    ICMP_STATS_INC(icmp.proterr);
    ICMP_STATS_INC(icmp.drop);
  }
  pbuf_free(p);
}

void
icmp_dest_unreach(struct pbuf *p, enum icmp_dur_type t)
{
  struct pbuf *q;
  struct ip_hdr *iphdr;
  struct icmp_dur_hdr *idur;

  q = pbuf_alloc(PBUF_IP, 8 + IP_HLEN + 8, PBUF_RAM);
  /* ICMP header + IP header + 8 bytes of data */

  iphdr = p->payload;

  idur = q->payload;
  ICMPH_TYPE_SET(idur, ICMP_DUR);
  ICMPH_CODE_SET(idur, t);

  memcpy((char *)q->payload + 8, p->payload, IP_HLEN + 8);

  /* calculate checksum */
  idur->chksum = 0;
  idur->chksum = inet_chksum(idur, q->len);
  ICMP_STATS_INC(icmp.xmit);
  /* increase number of messages attempted to send */
  snmp_inc_icmpoutmsgs();
  /* increase number of destination unreachable messages attempted to send */
  snmp_inc_icmpoutdestunreachs();

  ip_output(q, NULL, &(iphdr->src),
	    ICMP_TTL, 0, IP_PROTO_ICMP);
  pbuf_free(q);
}

#if IP_FORWARD
void
icmp_time_exceeded(struct pbuf *p, enum icmp_te_type t)
{
  struct pbuf *q;
  struct ip_hdr *iphdr;
  struct icmp_te_hdr *tehdr;

  q = pbuf_alloc(PBUF_IP, 8 + IP_HLEN + 8, PBUF_RAM);

  iphdr = p->payload;
  LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded from "));
  ip_addr_debug_print(ICMP_DEBUG, &(iphdr->src));
  LWIP_DEBUGF(ICMP_DEBUG, (" to "));
  ip_addr_debug_print(ICMP_DEBUG, &(iphdr->dest));
  LWIP_DEBUGF(ICMP_DEBUG, ("\n"));

  tehdr = q->payload;
  ICMPH_TYPE_SET(tehdr, ICMP_TE);
  ICMPH_CODE_SET(tehdr, t);

  /* copy fields from original packet */
  memcpy((char *)q->payload + 8, (char *)p->payload, IP_HLEN + 8);

  /* calculate checksum */
  tehdr->chksum = 0;
  tehdr->chksum = inet_chksum(tehdr, q->len);
  ICMP_STATS_INC(icmp.xmit);
  /* increase number of messages attempted to send */
  snmp_inc_icmpoutmsgs();
  /* increase number of destination unreachable messages attempted to send */
  snmp_inc_icmpouttimeexcds();
  ip_output(q, NULL, &(iphdr->src),
	    ICMP_TTL, 0, IP_PROTO_ICMP);
  pbuf_free(q);
}

#endif /* IP_FORWARD */








--- NEW FILE: ip.c ---
/*
 * 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 <ad...@si...>
 *
 */



/* ip.c
 *
 * This is the code for the IP layer.
 *
 */


#include "lwip/opt.h"


#include "lwip/def.h"
#include "lwip/mem.h"
#include "lwip/ip.h"
#include "lwip/ip_frag.h"
#include "lwip/inet.h"
#include "lwip/netif.h"
#include "lwip/icmp.h"
#include "lwip/raw.h"
#include "lwip/udp.h"
#include "lwip/tcp.h"

#include "lwip/stats.h"

#include "arch/perf.h"

#include "lwip/snmp.h"
#if LWIP_DHCP
#  include "lwip/dhcp.h"
#endif /* LWIP_DHCP */


/* 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;

  /* iterate through netifs */
  for(netif = netif_list; netif != NULL; netif = netif->next) {
    /* network mask matches? */
    if (ip_addr_maskcmp(dest, &(netif->ip_addr), &(netif->netmask))) {
      /* return netif on which to forward IP packet */
      return netif;
    }
  }
  /* no matching netif found, use default netif */
  return netif_default;
}
#if IP_FORWARD

/* 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 *inp)
{
  struct netif *netif;

  PERF_START;
  /* Find network interface where to forward this IP packet to. */
  netif = ip_route((struct ip_addr *)&(iphdr->dest));
  if (netif == NULL) {
    LWIP_DEBUGF(IP_DEBUG, ("ip_forward: no forwarding route for 0x%lx found\n",
                      iphdr->dest.addr));
    snmp_inc_ipnoroutes();
    return;
  }
  /* Do not forward packets onto the same network interface on which
     they arrived. */
  if (netif == inp) {
    LWIP_DEBUGF(IP_DEBUG, ("ip_forward: not bouncing packets back on incoming interface.\n"));
    snmp_inc_ipnoroutes();
    return;
  }

  /* decrement TTL */
  IPH_TTL_SET(iphdr, IPH_TTL(iphdr) - 1);
  /* send ICMP if TTL == 0 */
  if (IPH_TTL(iphdr) == 0) {
    /* Don't send ICMP messages in response to ICMP messages */
    if (IPH_PROTO(iphdr) != IP_PROTO_ICMP) {
      icmp_time_exceeded(p, ICMP_TE_TTL);
      snmp_inc_icmpouttimeexcds();
    }
    return;
  }

  /* Incrementally update the IP checksum. */
  if (IPH_CHKSUM(iphdr) >= htons(0xffff - 0x100)) {
    IPH_CHKSUM_SET(iphdr, IPH_CHKSUM(iphdr) + htons(0x100) + 1);
  } else {
    IPH_CHKSUM_SET(iphdr, IPH_CHKSUM(iphdr) + htons(0x100));
  }

  LWIP_DEBUGF(IP_DEBUG, ("ip_forward: forwarding packet to 0x%lx\n",
                    iphdr->dest.addr));

  IP_STATS_INC(ip.fw);
  IP_STATS_INC(ip.xmit);
    snmp_inc_ipforwdatagrams();

  PERF_STOP("ip_forward");
  /* transmit pbuf on chosen interface */
  netif->output(netif, p, (struct ip_addr *)&(iphdr->dest));
}
#endif /* IP_FORWARD */

/* 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.
 */

err_t
ip_input(struct pbuf *p, struct netif *inp) {
  static struct ip_hdr *iphdr;
  static struct netif *netif;
  static u16_t iphdrlen;

  IP_STATS_INC(ip.recv);
  snmp_inc_ipinreceives();

  /* identify the IP header */
  iphdr = p->payload;
  if (IPH_V(iphdr) != 4) {
    LWIP_DEBUGF(IP_DEBUG | 1, ("IP packet dropped due to bad version number %u\n", IPH_V(iphdr)));
    ip_debug_print(p);
    pbuf_free(p);
    IP_STATS_INC(ip.err);
    IP_STATS_INC(ip.drop);
    snmp_inc_ipunknownprotos();
    return ERR_OK;
  }
  /* obtain IP header length in number of 32-bit words */
  iphdrlen = IPH_HL(iphdr);
  /* calculate IP header length in bytes */
  iphdrlen *= 4;

  /* header length exceeds first pbuf length? */
  if (iphdrlen > p->len) {
    LWIP_DEBUGF(IP_DEBUG | 2, ("IP header (len %u) does not fit in first pbuf (len %u), IP packet droppped.\n",
      iphdrlen, p->len));
    /* free (drop) packet pbufs */
    pbuf_free(p);
    IP_STATS_INC(ip.lenerr);
    IP_STATS_INC(ip.drop);
    snmp_inc_ipindiscards();
    return ERR_OK;
  }

  /* verify checksum */
  if (inet_chksum(iphdr, iphdrlen) != 0) {

    LWIP_DEBUGF(IP_DEBUG | 2, ("Checksum (0x%x) failed, IP packet dropped.\n", inet_chksum(iphdr, iphdrlen)));
    ip_debug_print(p);
    pbuf_free(p);
    IP_STATS_INC(ip.chkerr);
    IP_STATS_INC(ip.drop);
    snmp_inc_ipindiscards();
    return ERR_OK;
  }

  /* Trim pbuf. This should have been done at the netif layer,
     but we'll do it anyway just to be sure that its done. */
  pbuf_realloc(p, ntohs(IPH_LEN(iphdr)));

  /* is this packet for us? */
  for(netif = netif_list; netif != NULL; netif = netif->next) {

    LWIP_DEBUGF(IP_DEBUG, ("ip_input: iphdr->dest 0x%lx netif->ip_addr 0x%lx (0x%lx, 0x%lx, 0x%lx)\n",
                      iphdr->dest.addr, netif->ip_addr.addr,
                      iphdr->dest.addr & netif->netmask.addr,
                      netif->ip_addr.addr & netif->netmask.addr,
                      iphdr->dest.addr & ~(netif->netmask.addr)));

    /* interface configured? */
    if (!ip_addr_isany(&(netif->ip_addr)))
    {
      /* unicast to this interface address? */
      if (ip_addr_cmp(&(iphdr->dest), &(netif->ip_addr)) ||
        /* or broadcast matching this interface network address? */
        (ip_addr_isbroadcast(&(iphdr->dest), &(netif->netmask)) &&
         ip_addr_maskcmp(&(iphdr->dest), &(netif->ip_addr), &(netif->netmask))) ||
         /* or restricted broadcast? */
         ip_addr_cmp(&(iphdr->dest), IP_ADDR_BROADCAST)) {
         LWIP_DEBUGF(IP_DEBUG, ("ip_input: packet accepted on interface %c%c\n",
                       netif->name[0], netif->name[1]));
         /* break out of for loop */
         break;
      }
    }
  }
#if LWIP_DHCP
  /* Pass DHCP messages regardless of destination address. DHCP traffic is addressed
     using link layer addressing (such as Ethernet MAC) so we must not filter on IP.
     According to RFC 1542 section 3.1.1, referred by RFC 2131). */
  if (netif == NULL) {
    /* remote port is DHCP server? */
    if (IPH_PROTO(iphdr) == IP_PROTO_UDP) {
      LWIP_DEBUGF(IP_DEBUG | DBG_TRACE | 1, ("ip_input: UDP packet to DHCP client port %u\n",
        ntohs(((struct udp_hdr *)((u8_t *)iphdr + iphdrlen))->dest)));
      if (ntohs(((struct udp_hdr *)((u8_t *)iphdr + iphdrlen))->dest) == DHCP_CLIENT_PORT) {
        LWIP_DEBUGF(IP_DEBUG | DBG_TRACE | 1, ("ip_input: DHCP packet accepted.\n"));
        netif = inp;
      }
    }
  }
#endif /* LWIP_DHCP */
        /* packet not for us? */
  if (netif == NULL) {
    /* packet not for us, route or discard */
    LWIP_DEBUGF(IP_DEBUG | DBG_TRACE | 1, ("ip_input: packet not for us.\n"));
#if IP_FORWARD
    /* non-broadcast packet? */
    if (!ip_addr_isbroadcast(&(iphdr->dest), &(inp->netmask))) {
      /* try to forward IP packet on (other) interfaces */
      ip_forward(p, iphdr, inp);
    }
    else
#endif /* IP_FORWARD */
    {
      snmp_inc_ipindiscards();
    }
    pbuf_free(p);
    return ERR_OK;
  }

#if IP_REASSEMBLY
  if ((IPH_OFFSET(iphdr) & htons(IP_OFFMASK | IP_MF)) != 0) {
    LWIP_DEBUGF(IP_DEBUG, ("IP packet is a fragment (id=0x%04x tot_len=%u len=%u MF=%u offset=%u), calling ip_reass()\n",
      ntohs(IPH_ID(iphdr)), p->tot_len, ntohs(IPH_LEN(iphdr)), !!(IPH_OFFSET(iphdr) & htons(IP_MF)), (ntohs(IPH_OFFSET(iphdr)) & IP_OFFMASK)*8));
    p = ip_reass(p);
    if (p == NULL) {
      return ERR_OK;
    }
    iphdr = p->payload;
  }
#else /* IP_REASSEMBLY */
  if ((IPH_OFFSET(iphdr) & htons(IP_OFFMASK | IP_MF)) != 0) {
    pbuf_free(p);
    LWIP_DEBUGF(IP_DEBUG | 2, ("IP packet dropped since it was fragmented (0x%x) (while IP_REASSEMBLY == 0).\n",
                  ntohs(IPH_OFFSET(iphdr))));
    IP_STATS_INC(ip.opterr);
    IP_STATS_INC(ip.drop);
    snmp_inc_ipunknownprotos();
    return ERR_OK;
  }
#endif /* IP_REASSEMBLY */

#if IP_OPTIONS == 0
  if (iphdrlen > IP_HLEN) {
    LWIP_DEBUGF(IP_DEBUG | 2, ("IP packet dropped since there were IP options (while IP_OPTIONS == 0).\n"));
    pbuf_free(p);
    IP_STATS_INC(ip.opterr);
    IP_STATS_INC(ip.drop);
    snmp_inc_ipunknownprotos();
    return ERR_OK;
  }
#endif /* IP_OPTIONS == 0 */

  /* send to upper layers */
  LWIP_DEBUGF(IP_DEBUG, ("ip_input: \n"));
  ip_debug_print(p);
  LWIP_DEBUGF(IP_DEBUG, ("ip_input: p->len %d p->tot_len %d\n", p->len, p->tot_len));

#if LWIP_RAW
  if (!raw_input(p, inp)) {
#endif /* LWIP_RAW */

  switch (IPH_PROTO(iphdr)) {
#if LWIP_UDP
  case IP_PROTO_UDP:
  case IP_PROTO_UDPLITE:
    snmp_inc_ipindelivers();
    udp_input(p, inp);
    break;
#endif /* LWIP_UDP */
#if LWIP_TCP
  case IP_PROTO_TCP:
    snmp_inc_ipindelivers();
    tcp_input(p, inp);
    break;
#endif /* LWIP_TCP */
  case IP_PROTO_ICMP:
    snmp_inc_ipindelivers();
    icmp_input(p, inp);
    break;
  default:
    /* send ICMP destination protocol unreachable unless is was a broadcast */
    if (!ip_addr_isbroadcast(&(iphdr->dest), &(inp->netmask)) &&
       !ip_addr_ismulticast(&(iphdr->dest))) {
      p->payload = iphdr;
      icmp_dest_unreach(p, ICMP_DUR_PROTO);
    }
    pbuf_free(p);

    LWIP_DEBUGF(IP_DEBUG | 2, ("Unsupported transport protocol %d\n", IPH_PROTO(iphdr)));

    IP_STATS_INC(ip.proterr);
    IP_STATS_INC(ip.drop);
    snmp_inc_ipunknownprotos();

  }
#if LWIP_RAW
  } /* LWIP_RAW */
#endif
  return ERR_OK;
}


/* 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 tos,
             u8_t proto, struct netif *netif)
{
  static struct ip_hdr *iphdr;
  static u16_t ip_id = 0;

  snmp_inc_ipoutrequests();

  if (dest != IP_HDRINCL) {
    if (pbuf_header(p, IP_HLEN)) {
      LWIP_DEBUGF(IP_DEBUG | 2, ("ip_output: not enough room for IP header in pbuf\n"));

      IP_STATS_INC(ip.err);
      snmp_inc_ipoutdiscards();
      return ERR_BUF;
    }

    iphdr = p->payload;

    IPH_TTL_SET(iphdr, ttl);
    IPH_PROTO_SET(iphdr, proto);

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

    IPH_VHLTOS_SET(iphdr, 4, IP_HLEN / 4, tos);
    IPH_LEN_SET(iphdr, htons(p->tot_len));
    IPH_OFFSET_SET(iphdr, htons(IP_DF));
    IPH_ID_SET(iphdr, htons(ip_id));
    ++ip_id;

    if (ip_addr_isany(src)) {
      ip_addr_set(&(iphdr->src), &(netif->ip_addr));
    } else {
      ip_addr_set(&(iphdr->src), src);
    }

    IPH_CHKSUM_SET(iphdr, 0);
    IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
  } else {
    iphdr = p->payload;
    dest = &(iphdr->dest);
  }

#if IP_FRAG
  /* don't fragment if interface has mtu set to 0 [loopif] */
  if (netif->mtu && (p->tot_len > netif->mtu))
    return ip_frag(p,netif,dest);
#endif

  IP_STATS_INC(ip.xmit);

  LWIP_DEBUGF(IP_DEBUG, ("ip_output_if: %c%c%u\n", netif->name[0], netif->name[1], netif->num));
  ip_debug_print(p);

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

  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 tos, u8_t proto)
{
  struct netif *netif;

  if ((netif = ip_route(dest)) == NULL) {
    LWIP_DEBUGF(IP_DEBUG | 2, ("ip_output: No route to 0x%lx\n", dest->addr));

    IP_STATS_INC(ip.rterr);
    snmp_inc_ipoutdiscards();
    return ERR_RTE;
  }

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

#if IP_DEBUG
void
ip_debug_print(struct pbuf *p)
{
  struct ip_hdr *iphdr = p->payload;
  u8_t *payload;

  payload = (u8_t *)iphdr + IP_HLEN;

  LWIP_DEBUGF(IP_DEBUG, ("IP header:\n"));
  LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
  LWIP_DEBUGF(IP_DEBUG, ("|%2d |%2d |  0x%02x |     %5u     | (v, hl, tos, len)\n",
                    IPH_V(iphdr),
                    IPH_HL(iphdr),
                    IPH_TOS(iphdr),
                    ntohs(IPH_LEN(iphdr))));
  LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
  LWIP_DEBUGF(IP_DEBUG, ("|    %5u      |%u%u%u|    %4u   | (id, flags, offset)\n",
                    ntohs(IPH_ID(iphdr)),
                    ntohs(IPH_OFFSET(iphdr)) >> 15 & 1,
                    ntohs(IPH_OFFSET(iphdr)) >> 14 & 1,
                    ntohs(IPH_OFFSET(iphdr)) >> 13 & 1,
                    ntohs(IPH_OFFSET(iphdr)) & IP_OFFMASK));
  LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
  LWIP_DEBUGF(IP_DEBUG, ("|  %3u  |  %3u  |    0x%04x     | (ttl, proto, chksum)\n",
                    IPH_TTL(iphdr),
                    IPH_PROTO(iphdr),
                    ntohs(IPH_CHKSUM(iphdr))));
  LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
  LWIP_DEBUGF(IP_DEBUG, ("|  %3ld  |  %3ld  |  %3ld  |  %3ld  | (src)\n",
                    ntohl(iphdr->src.addr) >> 24 & 0xff,
                    ntohl(iphdr->src.addr) >> 16 & 0xff,
                    ntohl(iphdr->src.addr) >> 8 & 0xff,
                    ntohl(iphdr->src.addr) & 0xff));
  LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
  LWIP_DEBUGF(IP_DEBUG, ("|  %3ld  |  %3ld  |  %3ld  |  %3ld  | (dest)\n",
                    ntohl(iphdr->dest.addr) >> 24 & 0xff,
                    ntohl(iphdr->dest.addr) >> 16 & 0xff,
                    ntohl(iphdr->dest.addr) >> 8 & 0xff,
                    ntohl(iphdr->dest.addr) & 0xff));
  LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
}
#endif /* IP_DEBUG */







--- NEW FILE: ip_addr.c ---
/*
 * 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 <ad...@si...>
 *
 */

#include "lwip/ip_addr.h"
#include "lwip/inet.h"

/* used by IP_ADDR_ANY and IP_ADDR_BROADCAST in ip_addr.h */
const struct ip_addr ip_addr_any = { 0x00000000UL };
const struct ip_addr ip_addr_broadcast = { 0xffffffffUL };

--- NEW FILE: ip_frag.c ---
/*
 * 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: Jani Monoses <ja...@iv...> 
 * original reassembly code by Adam Dunkels <ad...@si...>
 * 
 */


/* ip_frag.c
 *
 * This is the code for IP segmentation and reassembly
 *
 */


#include "lwip/opt.h"
#include "lwip/sys.h"
#include "lwip/ip.h"
#include "lwip/ip_frag.h"
#include "lwip/netif.h"

#include "lwip/stats.h"


/*
 * Copy len bytes from offset in pbuf to buffer 
 *
 * helper used by both ip_reass and ip_frag
 */
static struct pbuf *
copy_from_pbuf(struct pbuf *p, u16_t * offset,
           u8_t * buffer, u16_t len)
{
  u16_t l;

  p->payload = (u8_t *)p->payload + *offset;
  p->len -= *offset;
  while (len) {
    l = len < p->len ? len : p->len;
    memcpy(buffer, p->payload, l);
    buffer += l;
    len -= l;
    if (len)
      p = p->next;
    else
      *offset = l;
  }
  return p;
}

#define IP_REASS_BUFSIZE 5760
#define IP_REASS_MAXAGE 30
#define IP_REASS_TMO 1000

static u8_t ip_reassbuf[IP_HLEN + IP_REASS_BUFSIZE];
static u8_t ip_reassbitmap[IP_REASS_BUFSIZE / (8 * 8)];
static const u8_t bitmap_bits[8] = { 0xff, 0x7f, 0x3f, 0x1f,
  0x0f, 0x07, 0x03, 0x01
};
static u16_t ip_reasslen;
static u8_t ip_reassflags;
#define IP_REASS_FLAG_LASTFRAG 0x01

static u8_t ip_reasstmr;

/* Reassembly timer */ 
static void 
ip_reass_timer(void *arg)
{
  (void)arg;
  if (ip_reasstmr > 1) {
    ip_reasstmr--;
    sys_timeout(IP_REASS_TMO, ip_reass_timer, NULL);
  } else if (ip_reasstmr == 1)
  ip_reasstmr = 0;
}

struct pbuf *
ip_reass(struct pbuf *p)
{
  struct pbuf *q;
  struct ip_hdr *fraghdr, *iphdr;
  u16_t offset, len;
  u16_t i;

  IPFRAG_STATS_INC(ip_frag.recv);

  iphdr = (struct ip_hdr *) ip_reassbuf;
  fraghdr = (struct ip_hdr *) p->payload;
  /* If ip_reasstmr is zero, no packet is present in the buffer, so we
     write the IP header of the fragment into the reassembly
     buffer. The timer is updated with the maximum age. */
  if (ip_reasstmr == 0) {
    LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass: new packet\n"));
    memcpy(iphdr, fraghdr, IP_HLEN);
    ip_reasstmr = IP_REASS_MAXAGE;
    sys_timeout(IP_REASS_TMO, ip_reass_timer, NULL);
    ip_reassflags = 0;
    /* Clear the bitmap. */
    memset(ip_reassbitmap, 0, sizeof(ip_reassbitmap));
  }

  /* Check if the incoming fragment matches the one currently present
     in the reasembly buffer. If so, we proceed with copying the
     fragment into the buffer. */
  if (ip_addr_cmp(&iphdr->src, &fraghdr->src) &&
      ip_addr_cmp(&iphdr->dest, &fraghdr->dest) &&
      IPH_ID(iphdr) == IPH_ID(fraghdr)) {
    LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass: matching old packet\n"));
    IPFRAG_STATS_INC(ip_frag.cachehit);
    /* Find out the offset in the reassembly buffer where we should
       copy the fragment. */
    len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4;
    offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8;

    /* If the offset or the offset + fragment length overflows the
       reassembly buffer, we discard the entire packet. */
    if (offset > IP_REASS_BUFSIZE || offset + len > IP_REASS_BUFSIZE) {
      LWIP_DEBUGF(IP_REASS_DEBUG,
       ("ip_reass: fragment outside of buffer (%d:%d/%d).\n", offset,
        offset + len, IP_REASS_BUFSIZE));
      sys_untimeout(ip_reass_timer, NULL);
      ip_reasstmr = 0;
      goto nullreturn;
    }

    /* Copy the fragment into the reassembly buffer, at the right
       offset. */
    LWIP_DEBUGF(IP_REASS_DEBUG,
     ("ip_reass: copying with offset %d into %d:%d\n", offset,
      IP_HLEN + offset, IP_HLEN + offset + len));
    i = IPH_HL(fraghdr) * 4;
    copy_from_pbuf(p, &i, &ip_reassbuf[IP_HLEN + offset], len);

    /* Update the bitmap. */
    if (offset / (8 * 8) == (offset + len) / (8 * 8)) {
      LWIP_DEBUGF(IP_REASS_DEBUG,
       ("ip_reass: updating single byte in bitmap.\n"));
      /* If the two endpoints are in the same byte, we only update
         that byte. */
      ip_reassbitmap[offset / (8 * 8)] |=
    bitmap_bits[(offset / 8) & 7] &
    ~bitmap_bits[((offset + len) / 8) & 7];
    } else {
      /* If the two endpoints are in different bytes, we update the
         bytes in the endpoints and fill the stuff inbetween with
         0xff. */
      ip_reassbitmap[offset / (8 * 8)] |= bitmap_bits[(offset / 8) & 7];
      LWIP_DEBUGF(IP_REASS_DEBUG,
       ("ip_reass: updating many bytes in bitmap (%d:%d).\n",
        1 + offset / (8 * 8), (offset + len) / (8 * 8)));
      for (i = 1 + offset / (8 * 8); i < (offset + len) / (8 * 8); ++i) {
  ip_reassbitmap[i] = 0xff;
      }
      ip_reassbitmap[(offset + len) / (8 * 8)] |=
    ~bitmap_bits[((offset + len) / 8) & 7];
    }

    /* If this fragment has the More Fragments flag set to zero, we
       know that this is the last fragment, so we can calculate the
       size of the entire packet. We also set the
       IP_REASS_FLAG_LASTFRAG flag to indicate that we have received
       the final fragment. */

    if ((ntohs(IPH_OFFSET(fraghdr)) & IP_MF) == 0) {
      ip_reassflags |= IP_REASS_FLAG_LASTFRAG;
      ip_reasslen = offset + len;
      LWIP_DEBUGF(IP_REASS_DEBUG,
       ("ip_reass: last fragment seen, total len %d\n",
        ip_reasslen));
    }

    /* Finally, we check if we have a full packet in the buffer. We do
       this by checking if we have the last fragment and if all bits
       in the bitmap are set. */
    if (ip_reassflags & IP_REASS_FLAG_LASTFRAG) {
      /* Check all bytes up to and including all but the last byte in
         the bitmap. */
      for (i = 0; i < ip_reasslen / (8 * 8) - 1; ++i) {
  if (ip_reassbitmap[i] != 0xff) {
    LWIP_DEBUGF(IP_REASS_DEBUG,
     ("ip_reass: last fragment seen, bitmap %d/%d failed (%x)\n",
      i, ip_reasslen / (8 * 8) - 1, ip_reassbitmap[i]));
    goto nullreturn;
  }
      }
      /* Check the last byte in the bitmap. It should contain just the
         right amount of bits. */
      if (ip_reassbitmap[ip_reasslen / (8 * 8)] !=
    (u8_t) ~ bitmap_bits[ip_reasslen / 8 & 7]) {
  LWIP_DEBUGF(IP_REASS_DEBUG,
         ("ip_reass: last fragment seen, bitmap %d didn't contain %x (%x)\n",
    ip_reasslen / (8 * 8), ~bitmap_bits[ip_reasslen / 8 & 7],
    ip_reassbitmap[ip_reasslen / (8 * 8)]));
  goto nullreturn;
      }

      /* Pretend to be a "normal" (i.e., not fragmented) IP packet
         from now on. */
      ip_reasslen += IP_HLEN;

      IPH_LEN_SET(iphdr, htons(ip_reasslen));
      IPH_OFFSET_SET(iphdr, 0);
      IPH_CHKSUM_SET(iphdr, 0);
      IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));

      /* If we have come this far, we have a full packet in the
         buffer, so we allocate a pbuf and copy the packet into it. We
         also reset the timer. */
      sys_untimeout(ip_reass_timer, NULL);
      ip_reasstmr = 0;
      pbuf_free(p);
      p = pbuf_alloc(PBUF_LINK, ip_reasslen, PBUF_POOL);
      if (p != NULL) {
  i = 0;
  for (q = p; q != NULL; q = q->next) {
    /* Copy enough bytes to fill this pbuf in the chain. The
       available data in the pbuf is given by the q->len
       variable. */
    LWIP_DEBUGF(IP_REASS_DEBUG,
     ("ip_reass: memcpy from %p (%d) to %p, %d bytes\n",
      &ip_reassbuf[i], i, q->payload,
      q->len > ip_reasslen - i ? ip_reasslen - i : q->len));
    memcpy(q->payload, &ip_reassbuf[i],
    q->len > ip_reasslen - i ? ip_reasslen - i : q->len);
    i += q->len;
  }
  IPFRAG_STATS_INC(ip_frag.fw);
      } else {
  IPFRAG_STATS_INC(ip_frag.memerr);
      }
      LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass: p %p\n", (void*)p));
      return p;
    }
  }

nullreturn:
  IPFRAG_STATS_INC(ip_frag.drop);
  pbuf_free(p);
  return NULL;
}

#define MAX_MTU 1500
static u8_t buf[MEM_ALIGN_SIZE(MAX_MTU)];

/**
 * Fragment an IP packet if too large
 *
 * Chop the packet in mtu sized chunks and send them in order
 * by using a fixed size static memory buffer (PBUF_ROM)
 */
err_t 
ip_frag(struct pbuf *p, struct netif *netif, struct ip_addr *dest)
{
  struct pbuf *rambuf;
  struct pbuf *header;
  struct ip_hdr *iphdr;
  u16_t nfb = 0;
  u16_t left, cop;
  u16_t mtu = netif->mtu;
  u16_t ofo, omf;
  u16_t last;
  u16_t poff = IP_HLEN;
  u16_t tmp;

  /* Get a RAM based MTU sized pbuf */
  rambuf = pbuf_alloc(PBUF_LINK, 0, PBUF_REF);
  rambuf->tot_len = rambuf->len = mtu;
  rambuf->payload = MEM_ALIGN((void *)buf);


  /* Copy the IP header in it */
  iphdr = rambuf->payload;
  memcpy(iphdr, p->payload, IP_HLEN);

  /* Save original offset */
  tmp = ntohs(IPH_OFFSET(iphdr));
  ofo = tmp & IP_OFFMASK;
  omf = tmp & IP_MF;

  left = p->tot_len - IP_HLEN;

  while (left) {
    last = (left <= mtu - IP_HLEN);

    /* Set new offset and MF flag */
    ofo += nfb;
    tmp = omf | (IP_OFFMASK & (ofo));
    if (!last)
      tmp = tmp | IP_MF;
    IPH_OFFSET_SET(iphdr, htons(tmp));

    /* Fill this fragment */
    nfb = (mtu - IP_HLEN) / 8;
    cop = last ? left : nfb * 8;

    p = copy_from_pbuf(p, &poff, (u8_t *) iphdr + IP_HLEN, cop);

    /* Correct header */
    IPH_LEN_SET(iphdr, htons(cop + IP_HLEN));
    IPH_CHKSUM_SET(iphdr, 0);
    IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));

    if (last)
      pbuf_realloc(rambuf, left + IP_HLEN);
    /* This part is ugly: we alloc a RAM based pbuf for 
     * the link level header for each chunk and then 
     * free it.A PBUF_ROM style pbuf for which pbuf_header
     * worked would make things simpler.
     */
    header = pbuf_alloc(PBUF_LINK, 0, PBUF_RAM);
    pbuf_chain(header, rambuf);
    netif->output(netif, header, dest);
    IPFRAG_STATS_INC(ip_frag.xmit);
    pbuf_free(header);

    left -= cop;
  }
  pbuf_free(rambuf);
  return ERR_OK;
}