lwip/src/core/ipv6/ip6.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 <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 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 */
Commit	Line	Data
	1	/*
	2	* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
	3	* All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms, with or without modification,
	6	* are permitted provided that the following conditions are met:
	7	*
	8	* 1. Redistributions of source code must retain the above copyright notice,
	9	* this list of conditions and the following disclaimer.
	10	* 2. Redistributions in binary form must reproduce the above copyright notice,
	11	* this list of conditions and the following disclaimer in the documentation
	12	* and/or other materials provided with the distribution.
	13	* 3. The name of the author may not be used to endorse or promote products
	14	* derived from this software without specific prior written permission.
	15	*
	16	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
	17	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
	18	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
	19	* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
	20	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
	21	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
	22	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
	23	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
	24	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
	25	* OF SUCH DAMAGE.
	26	*
	27	* This file is part of the lwIP TCP/IP stack.
	28	*
	29	* Author: Adam Dunkels <adam@sics.se>
	30	*
	31	*/
	32
	33
	34
	35	/* ip.c
	36	*
	37	* This is the code for the IP layer for IPv6.
	38	*
	39	*/
	40
	41
	42	#include "lwip/opt.h"
	43
	44	#include "lwip/def.h"
	45	#include "lwip/mem.h"
	46	#include "lwip/ip.h"
	47	#include "lwip/inet.h"
	48	#include "lwip/netif.h"
	49	#include "lwip/icmp.h"
	50	#include "lwip/udp.h"
	51	#include "lwip/tcp.h"
	52
	53	#include "lwip/stats.h"
	54
	55	#include "arch/perf.h"
	56
	57	/* ip_init:
	58	*
	59	* Initializes the IP layer.
	60	*/
	61
	62	void
	63	ip_init(void)
	64	{
	65	}
	66
	67	/* ip_route:
	68	*
	69	* Finds the appropriate network interface for a given IP address. It searches the
	70	* list of network interfaces linearly. A match is found if the masked IP address of
	71	* the network interface equals the masked IP address given to the function.
	72	*/
	73
	74	struct netif *
	75	ip_route(struct ip_addr *dest)
	76	{
	77	struct netif *netif;
	78
	79	for(netif = netif_list; netif != NULL; netif = netif->next) {
	80	if (ip_addr_netcmp(dest, &(netif->ip_addr), &(netif->netmask))) {
	81	return netif;
	82	}
	83	}
	84
	85	return netif_default;
	86	}
	87
	88	/* ip_forward:
	89	*
	90	* Forwards an IP packet. It finds an appropriate route for the packet, decrements
	91	* the TTL value of the packet, adjusts the checksum and outputs the packet on the
	92	* appropriate interface.
	93	*/
	94
	95	static void
	96	ip_forward(struct pbuf p, struct ip_hdr iphdr)
	97	{
	98	struct netif *netif;
	99
	100	PERF_START;
	101
	102	if ((netif = ip_route((struct ip_addr *)&(iphdr->dest))) == NULL) {
	103
	104	LWIP_DEBUGF(IP_DEBUG, ("ip_input: no forwarding route found for "));
	105	#if IP_DEBUG
	106	ip_addr_debug_print(IP_DEBUG, ((struct ip_addr *)&(iphdr->dest)));
	107	#endif /* IP_DEBUG */
	108	LWIP_DEBUGF(IP_DEBUG, ("\n"));
	109	pbuf_free(p);
	110	return;
	111	}
	112	/* Decrement TTL and send ICMP if ttl == 0. */
	113	if (--iphdr->hoplim == 0) {
	114	#if LWIP_ICMP
	115	/* Don't send ICMP messages in response to ICMP messages */
	116	if (iphdr->nexthdr != IP_PROTO_ICMP) {
	117	icmp_time_exceeded(p, ICMP_TE_TTL);
	118	}
	119	#endif /* LWIP_ICMP */
	120	pbuf_free(p);
	121	return;
	122	}
	123
	124	/* Incremental update of the IP checksum. */
	125	/* if (iphdr->chksum >= htons(0xffff - 0x100)) {
	126	iphdr->chksum += htons(0x100) + 1;
	127	} else {
	128	iphdr->chksum += htons(0x100);
	129	}*/
	130
	131
	132	LWIP_DEBUGF(IP_DEBUG, ("ip_forward: forwarding packet to "));
	133	#if IP_DEBUG
	134	ip_addr_debug_print(IP_DEBUG, ((struct ip_addr *)&(iphdr->dest)));
	135	#endif /* IP_DEBUG */
	136	LWIP_DEBUGF(IP_DEBUG, ("\n"));
	137
	138	IP_STATS_INC(ip.fw);
	139	IP_STATS_INC(ip.xmit);
	140
	141	PERF_STOP("ip_forward");
	142
	143	netif->output(netif, p, (struct ip_addr *)&(iphdr->dest));
	144	}
	145
	146	/* ip_input:
	147	*
	148	* This function is called by the network interface device driver when an IP packet is
	149	* received. The function does the basic checks of the IP header such as packet size
	150	* being at least larger than the header size etc. If the packet was not destined for
	151	* us, the packet is forwarded (using ip_forward). The IP checksum is always checked.
	152	*
	153	* Finally, the packet is sent to the upper layer protocol input function.
	154	*/
	155
	156	void
	157	ip_input(struct pbuf p, struct netif inp) {
	158	struct ip_hdr *iphdr;
	159	struct netif *netif;
	160
	161
	162	PERF_START;
	163
	164	#if IP_DEBUG
	165	ip_debug_print(p);
	166	#endif /* IP_DEBUG */
	167
	168
	169	IP_STATS_INC(ip.recv);
	170
	171	/* identify the IP header */
	172	iphdr = p->payload;
	173
	174
	175	if (iphdr->v != 6) {
	176	LWIP_DEBUGF(IP_DEBUG, ("IP packet dropped due to bad version number\n"));
	177	#if IP_DEBUG
	178	ip_debug_print(p);
	179	#endif /* IP_DEBUG */
	180	pbuf_free(p);
	181	IP_STATS_INC(ip.err);
	182	IP_STATS_INC(ip.drop);
	183	return;
	184	}
	185
	186	/* is this packet for us? */
	187	for(netif = netif_list; netif != NULL; netif = netif->next) {
	188	#if IP_DEBUG
	189	LWIP_DEBUGF(IP_DEBUG, ("ip_input: iphdr->dest "));
	190	ip_addr_debug_print(IP_DEBUG, ((struct ip_addr *)&(iphdr->dest)));
	191	LWIP_DEBUGF(IP_DEBUG, ("netif->ip_addr "));
	192	ip_addr_debug_print(IP_DEBUG, ((struct ip_addr *)&(iphdr->dest)));
	193	LWIP_DEBUGF(IP_DEBUG, ("\n"));
	194	#endif /* IP_DEBUG */
	195	if (ip_addr_cmp(&(iphdr->dest), &(netif->ip_addr))) {
	196	break;
	197	}
	198	}
	199
	200
	201	if (netif == NULL) {
	202	/* packet not for us, route or discard */
	203	#if IP_FORWARD
	204	ip_forward(p, iphdr);
	205	#endif
	206	pbuf_free(p);
	207	return;
	208	}
	209
	210	pbuf_realloc(p, IP_HLEN + ntohs(iphdr->len));
	211
	212	/* send to upper layers */
	213	#if IP_DEBUG
	214	/* LWIP_DEBUGF("ip_input: \n");
	215	ip_debug_print(p);
	216	LWIP_DEBUGF("ip_input: p->len %"U16_F" p->tot_len %"U16_F"\n", p->len, p->tot_len);*/
	217	#endif /* IP_DEBUG */
	218
	219	if(pbuf_header(p, -IP_HLEN)) {
	220	LWIP_ASSERT("Can't move over header in packet", 0);
	221	return;
	222	}
	223
	224	switch (iphdr->nexthdr) {
	225	case IP_PROTO_UDP:
	226	udp_input(p, inp);
	227	break;
	228	case IP_PROTO_TCP:
	229	tcp_input(p, inp);
	230	break;
	231	#if LWIP_ICMP
	232	case IP_PROTO_ICMP:
	233	icmp_input(p, inp);
	234	break;
	235	#endif /* LWIP_ICMP */
	236	default:
	237	#if LWIP_ICMP
	238	/* send ICMP destination protocol unreachable */
	239	icmp_dest_unreach(p, ICMP_DUR_PROTO);
	240	#endif /* LWIP_ICMP */
	241	pbuf_free(p);
	242	LWIP_DEBUGF(IP_DEBUG, ("Unsupported transport protocol %"U16_F"\n",
	243	iphdr->nexthdr));
	244
	245	IP_STATS_INC(ip.proterr);
	246	IP_STATS_INC(ip.drop);
	247	}
	248	PERF_STOP("ip_input");
	249	}
	250
	251
	252	/* ip_output_if:
	253	*
	254	* Sends an IP packet on a network interface. This function constructs the IP header
	255	* and calculates the IP header checksum. If the source IP address is NULL,
	256	* the IP address of the outgoing network interface is filled in as source address.
	257	*/
	258
	259	err_t
	260	ip_output_if (struct pbuf p, struct ip_addr src, struct ip_addr *dest,
	261	u8_t ttl,
	262	u8_t proto, struct netif *netif)
	263	{
	264	struct ip_hdr *iphdr;
	265
	266	PERF_START;
	267
	268	LWIP_DEBUGF(IP_DEBUG, ("len %"U16_F" tot_len %"U16_F"\n", p->len, p->tot_len));
	269	if (pbuf_header(p, IP_HLEN)) {
	270	LWIP_DEBUGF(IP_DEBUG, ("ip_output: not enough room for IP header in pbuf\n"));
	271	IP_STATS_INC(ip.err);
	272
	273	return ERR_BUF;
	274	}
	275	LWIP_DEBUGF(IP_DEBUG, ("len %"U16_F" tot_len %"U16_F"\n", p->len, p->tot_len));
	276
	277	iphdr = p->payload;
	278
	279
	280	if (dest != IP_HDRINCL) {
	281	LWIP_DEBUGF(IP_DEBUG, ("!IP_HDRLINCL\n"));
	282	iphdr->hoplim = ttl;
	283	iphdr->nexthdr = proto;
	284	iphdr->len = htons(p->tot_len - IP_HLEN);
	285	ip_addr_set(&(iphdr->dest), dest);
	286
	287	iphdr->v = 6;
	288
	289	if (ip_addr_isany(src)) {
	290	ip_addr_set(&(iphdr->src), &(netif->ip_addr));
	291	} else {
	292	ip_addr_set(&(iphdr->src), src);
	293	}
	294
	295	} else {
	296	dest = &(iphdr->dest);
	297	}
	298
	299	IP_STATS_INC(ip.xmit);
	300
	301	LWIP_DEBUGF(IP_DEBUG, ("ip_output_if: %c%c (len %"U16_F")\n", netif->name[0], netif->name[1], p->tot_len));
	302	#if IP_DEBUG
	303	ip_debug_print(p);
	304	#endif /* IP_DEBUG */
	305
	306	PERF_STOP("ip_output_if");
	307	return netif->output(netif, p, dest);
	308	}
	309
	310	/* ip_output:
	311	*
	312	* Simple interface to ip_output_if. It finds the outgoing network interface and
	313	* calls upon ip_output_if to do the actual work.
	314	*/
	315
	316	err_t
	317	ip_output(struct pbuf p, struct ip_addr src, struct ip_addr *dest,
	318	u8_t ttl, u8_t proto)
	319	{
	320	struct netif *netif;
	321	if ((netif = ip_route(dest)) == NULL) {
	322	LWIP_DEBUGF(IP_DEBUG, ("ip_output: No route to 0x%"X32_F"\n", dest->addr));
	323	IP_STATS_INC(ip.rterr);
	324	return ERR_RTE;
	325	}
	326
	327	return ip_output_if (p, src, dest, ttl, proto, netif);
	328	}
	329
	330	#if IP_DEBUG
	331	void
	332	ip_debug_print(struct pbuf *p)
	333	{
	334	struct ip_hdr *iphdr = p->payload;
	335
	336	LWIP_DEBUGF(IP_DEBUG, ("IP header:\n"));
	337	LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
	338	LWIP_DEBUGF(IP_DEBUG, ("\|%2"S16_F" \| %"X16_F"%"X16_F" \| %"X16_F"%"X16_F" \| (v, traffic class, flow label)\n",
	339	iphdr->v,
	340	iphdr->tclass1, iphdr->tclass2,
	341	iphdr->flow1, iphdr->flow2));
	342	LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
	343	LWIP_DEBUGF(IP_DEBUG, ("\| %5"U16_F" \| %2"U16_F" \| %2"U16_F" \| (len, nexthdr, hoplim)\n",
	344	ntohs(iphdr->len),
	345	iphdr->nexthdr,
	346	iphdr->hoplim));
	347	LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
	348	LWIP_DEBUGF(IP_DEBUG, ("\| %4"X32_F" \| %4"X32_F" \| (src)\n",
	349	(ntohl(iphdr->src.addr[0]) >> 16) & 0xffff,
	350	ntohl(iphdr->src.addr[0]) & 0xffff));
	351	LWIP_DEBUGF(IP_DEBUG, ("\| %4"X32_F" \| %4"X32_F" \| (src)\n",
	352	(ntohl(iphdr->src.addr[1]) >> 16) & 0xffff,
	353	ntohl(iphdr->src.addr[1]) & 0xffff));
	354	LWIP_DEBUGF(IP_DEBUG, ("\| %4"X32_F" \| %4"X32_F" \| (src)\n",
	355	(ntohl(iphdr->src.addr[2]) >> 16) & 0xffff,
	356	ntohl(iphdr->src.addr[2]) & 0xffff));
	357	LWIP_DEBUGF(IP_DEBUG, ("\| %4"X32_F" \| %4"X32_F" \| (src)\n",
	358	(ntohl(iphdr->src.addr[3]) >> 16) & 0xffff,
	359	ntohl(iphdr->src.addr[3]) & 0xffff));
	360	LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
	361	LWIP_DEBUGF(IP_DEBUG, ("\| %4"X32_F" \| %4"X32_F" \| (dest)\n",
	362	(ntohl(iphdr->dest.addr[0]) >> 16) & 0xffff,
	363	ntohl(iphdr->dest.addr[0]) & 0xffff));
	364	LWIP_DEBUGF(IP_DEBUG, ("\| %4"X32_F" \| %4"X32_F" \| (dest)\n",
	365	(ntohl(iphdr->dest.addr[1]) >> 16) & 0xffff,
	366	ntohl(iphdr->dest.addr[1]) & 0xffff));
	367	LWIP_DEBUGF(IP_DEBUG, ("\| %4"X32_F" \| %4"X32_F" \| (dest)\n",
	368	(ntohl(iphdr->dest.addr[2]) >> 16) & 0xffff,
	369	ntohl(iphdr->dest.addr[2]) & 0xffff));
	370	LWIP_DEBUGF(IP_DEBUG, ("\| %4"X32_F" \| %4"X32_F" \| (dest)\n",
	371	(ntohl(iphdr->dest.addr[3]) >> 16) & 0xffff,
	372	ntohl(iphdr->dest.addr[3]) & 0xffff));
	373	LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
	374	}
	375	#endif /* IP_DEBUG */