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lwip/core/ipv4/icmp.c@0:d616ece2d859, 2010-09-18 (annotated)

Committer:: mbed714
Date:: Sat Sep 18 23:05:49 2010 +0000
Revision:: 0:d616ece2d859

Who changed what in which revision?

User	Revision	Line number	New contents of line
mbed714	0:d616ece2d859	1	/**
mbed714	0:d616ece2d859	2	* @file
mbed714	0:d616ece2d859	3	* ICMP - Internet Control Message Protocol
mbed714	0:d616ece2d859	4	*
mbed714	0:d616ece2d859	5	*/
mbed714	0:d616ece2d859	6
mbed714	0:d616ece2d859	7	/*
mbed714	0:d616ece2d859	8	* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
mbed714	0:d616ece2d859	9	* All rights reserved.
mbed714	0:d616ece2d859	10	*
mbed714	0:d616ece2d859	11	* Redistribution and use in source and binary forms, with or without modification,
mbed714	0:d616ece2d859	12	* are permitted provided that the following conditions are met:
mbed714	0:d616ece2d859	13	*
mbed714	0:d616ece2d859	14	* 1. Redistributions of source code must retain the above copyright notice,
mbed714	0:d616ece2d859	15	* this list of conditions and the following disclaimer.
mbed714	0:d616ece2d859	16	* 2. Redistributions in binary form must reproduce the above copyright notice,
mbed714	0:d616ece2d859	17	* this list of conditions and the following disclaimer in the documentation
mbed714	0:d616ece2d859	18	* and/or other materials provided with the distribution.
mbed714	0:d616ece2d859	19	* 3. The name of the author may not be used to endorse or promote products
mbed714	0:d616ece2d859	20	* derived from this software without specific prior written permission.
mbed714	0:d616ece2d859	21	*
mbed714	0:d616ece2d859	22	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
mbed714	0:d616ece2d859	23	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
mbed714	0:d616ece2d859	24	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
mbed714	0:d616ece2d859	25	* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
mbed714	0:d616ece2d859	26	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
mbed714	0:d616ece2d859	27	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
mbed714	0:d616ece2d859	28	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
mbed714	0:d616ece2d859	29	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
mbed714	0:d616ece2d859	30	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
mbed714	0:d616ece2d859	31	* OF SUCH DAMAGE.
mbed714	0:d616ece2d859	32	*
mbed714	0:d616ece2d859	33	* This file is part of the lwIP TCP/IP stack.
mbed714	0:d616ece2d859	34	*
mbed714	0:d616ece2d859	35	* Author: Adam Dunkels <adam@sics.se>
mbed714	0:d616ece2d859	36	*
mbed714	0:d616ece2d859	37	*/
mbed714	0:d616ece2d859	38
mbed714	0:d616ece2d859	39	/* Some ICMP messages should be passed to the transport protocols. This
mbed714	0:d616ece2d859	40	is not implemented. */
mbed714	0:d616ece2d859	41
mbed714	0:d616ece2d859	42	#include "lwip/opt.h"
mbed714	0:d616ece2d859	43
mbed714	0:d616ece2d859	44	#if LWIP_ICMP /* don't build if not configured for use in lwipopts.h */
mbed714	0:d616ece2d859	45
mbed714	0:d616ece2d859	46	#include "lwip/icmp.h"
mbed714	0:d616ece2d859	47	#include "lwip/inet_chksum.h"
mbed714	0:d616ece2d859	48	#include "lwip/ip.h"
mbed714	0:d616ece2d859	49	#include "lwip/def.h"
mbed714	0:d616ece2d859	50	#include "lwip/stats.h"
mbed714	0:d616ece2d859	51	#include "lwip/snmp.h"
mbed714	0:d616ece2d859	52
mbed714	0:d616ece2d859	53	#include <string.h>
mbed714	0:d616ece2d859	54
mbed714	0:d616ece2d859	55	/** Small optimization: set to 0 if incoming PBUF_POOL pbuf always can be
mbed714	0:d616ece2d859	56	* used to modify and send a response packet (and to 1 if this is not the case,
mbed714	0:d616ece2d859	57	* e.g. when link header is stripped of when receiving) */
mbed714	0:d616ece2d859	58	#ifndef LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
mbed714	0:d616ece2d859	59	#define LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN 1
mbed714	0:d616ece2d859	60	#endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
mbed714	0:d616ece2d859	61
mbed714	0:d616ece2d859	62	/* The amount of data from the original packet to return in a dest-unreachable */
mbed714	0:d616ece2d859	63	#define ICMP_DEST_UNREACH_DATASIZE 8
mbed714	0:d616ece2d859	64
mbed714	0:d616ece2d859	65	static void icmp_send_response(struct pbuf *p, u8_t type, u8_t code);
mbed714	0:d616ece2d859	66
mbed714	0:d616ece2d859	67	/**
mbed714	0:d616ece2d859	68	* Processes ICMP input packets, called from ip_input().
mbed714	0:d616ece2d859	69	*
mbed714	0:d616ece2d859	70	* Currently only processes icmp echo requests and sends
mbed714	0:d616ece2d859	71	* out the echo response.
mbed714	0:d616ece2d859	72	*
mbed714	0:d616ece2d859	73	* @param p the icmp echo request packet, p->payload pointing to the ip header
mbed714	0:d616ece2d859	74	* @param inp the netif on which this packet was received
mbed714	0:d616ece2d859	75	*/
mbed714	0:d616ece2d859	76	void
mbed714	0:d616ece2d859	77	icmp_input(struct pbuf p, struct netif inp)
mbed714	0:d616ece2d859	78	{
mbed714	0:d616ece2d859	79	u8_t type;
mbed714	0:d616ece2d859	80	#ifdef LWIP_DEBUG
mbed714	0:d616ece2d859	81	u8_t code;
mbed714	0:d616ece2d859	82	#endif /* LWIP_DEBUG */
mbed714	0:d616ece2d859	83	struct icmp_echo_hdr *iecho;
mbed714	0:d616ece2d859	84	struct ip_hdr *iphdr;
mbed714	0:d616ece2d859	85	s16_t hlen;
mbed714	0:d616ece2d859	86
mbed714	0:d616ece2d859	87	ICMP_STATS_INC(icmp.recv);
mbed714	0:d616ece2d859	88	snmp_inc_icmpinmsgs();
mbed714	0:d616ece2d859	89
mbed714	0:d616ece2d859	90
mbed714	0:d616ece2d859	91	iphdr = (struct ip_hdr *)p->payload;
mbed714	0:d616ece2d859	92	hlen = IPH_HL(iphdr) * 4;
mbed714	0:d616ece2d859	93	if (pbuf_header(p, -hlen) \|\| (p->tot_len < sizeof(u16_t)*2)) {
mbed714	0:d616ece2d859	94	LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: short ICMP (%"U16_F" bytes) received\n", p->tot_len));
mbed714	0:d616ece2d859	95	goto lenerr;
mbed714	0:d616ece2d859	96	}
mbed714	0:d616ece2d859	97
mbed714	0:d616ece2d859	98	type = ((u8_t )p->payload);
mbed714	0:d616ece2d859	99	#ifdef LWIP_DEBUG
mbed714	0:d616ece2d859	100	code = (((u8_t )p->payload)+1);
mbed714	0:d616ece2d859	101	#endif /* LWIP_DEBUG */
mbed714	0:d616ece2d859	102	switch (type) {
mbed714	0:d616ece2d859	103	case ICMP_ER:
mbed714	0:d616ece2d859	104	/* This is OK, echo reply might have been parsed by a raw PCB
mbed714	0:d616ece2d859	105	(as obviously, an echo request has been sent, too). */
mbed714	0:d616ece2d859	106	break;
mbed714	0:d616ece2d859	107	case ICMP_ECHO:
mbed714	0:d616ece2d859	108	#if !LWIP_MULTICAST_PING \|\| !LWIP_BROADCAST_PING
mbed714	0:d616ece2d859	109	{
mbed714	0:d616ece2d859	110	int accepted = 1;
mbed714	0:d616ece2d859	111	#if !LWIP_MULTICAST_PING
mbed714	0:d616ece2d859	112	/* multicast destination address? */
mbed714	0:d616ece2d859	113	if (ip_addr_ismulticast(&current_iphdr_dest)) {
mbed714	0:d616ece2d859	114	accepted = 0;
mbed714	0:d616ece2d859	115	}
mbed714	0:d616ece2d859	116	#endif /* LWIP_MULTICAST_PING */
mbed714	0:d616ece2d859	117	#if !LWIP_BROADCAST_PING
mbed714	0:d616ece2d859	118	/* broadcast destination address? */
mbed714	0:d616ece2d859	119	if (ip_addr_isbroadcast(&current_iphdr_dest, inp)) {
mbed714	0:d616ece2d859	120	accepted = 0;
mbed714	0:d616ece2d859	121	}
mbed714	0:d616ece2d859	122	#endif /* LWIP_BROADCAST_PING */
mbed714	0:d616ece2d859	123	/* broadcast or multicast destination address not acceptd? */
mbed714	0:d616ece2d859	124	if (!accepted) {
mbed714	0:d616ece2d859	125	LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to multicast or broadcast pings\n"));
mbed714	0:d616ece2d859	126	ICMP_STATS_INC(icmp.err);
mbed714	0:d616ece2d859	127	pbuf_free(p);
mbed714	0:d616ece2d859	128	return;
mbed714	0:d616ece2d859	129	}
mbed714	0:d616ece2d859	130	}
mbed714	0:d616ece2d859	131	#endif /* !LWIP_MULTICAST_PING \|\| !LWIP_BROADCAST_PING */
mbed714	0:d616ece2d859	132	LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ping\n"));
mbed714	0:d616ece2d859	133	if (p->tot_len < sizeof(struct icmp_echo_hdr)) {
mbed714	0:d616ece2d859	134	LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: bad ICMP echo received\n"));
mbed714	0:d616ece2d859	135	goto lenerr;
mbed714	0:d616ece2d859	136	}
mbed714	0:d616ece2d859	137	if (inet_chksum_pbuf(p) != 0) {
mbed714	0:d616ece2d859	138	LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: checksum failed for received ICMP echo\n"));
mbed714	0:d616ece2d859	139	pbuf_free(p);
mbed714	0:d616ece2d859	140	ICMP_STATS_INC(icmp.chkerr);
mbed714	0:d616ece2d859	141	snmp_inc_icmpinerrors();
mbed714	0:d616ece2d859	142	return;
mbed714	0:d616ece2d859	143	}
mbed714	0:d616ece2d859	144	#if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
mbed714	0:d616ece2d859	145	if (pbuf_header(p, (PBUF_IP_HLEN + PBUF_LINK_HLEN))) {
mbed714	0:d616ece2d859	146	/* p is not big enough to contain link headers
mbed714	0:d616ece2d859	147	* allocate a new one and copy p into it
mbed714	0:d616ece2d859	148	*/
mbed714	0:d616ece2d859	149	struct pbuf *r;
mbed714	0:d616ece2d859	150	/* switch p->payload to ip header */
mbed714	0:d616ece2d859	151	if (pbuf_header(p, hlen)) {
mbed714	0:d616ece2d859	152	LWIP_ASSERT("icmp_input: moving p->payload to ip header failed\n", 0);
mbed714	0:d616ece2d859	153	goto memerr;
mbed714	0:d616ece2d859	154	}
mbed714	0:d616ece2d859	155	/* allocate new packet buffer with space for link headers */
mbed714	0:d616ece2d859	156	r = pbuf_alloc(PBUF_LINK, p->tot_len, PBUF_RAM);
mbed714	0:d616ece2d859	157	if (r == NULL) {
mbed714	0:d616ece2d859	158	LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: allocating new pbuf failed\n"));
mbed714	0:d616ece2d859	159	goto memerr;
mbed714	0:d616ece2d859	160	}
mbed714	0:d616ece2d859	161	LWIP_ASSERT("check that first pbuf can hold struct the ICMP header",
mbed714	0:d616ece2d859	162	(r->len >= hlen + sizeof(struct icmp_echo_hdr)));
mbed714	0:d616ece2d859	163	/* copy the whole packet including ip header */
mbed714	0:d616ece2d859	164	if (pbuf_copy(r, p) != ERR_OK) {
mbed714	0:d616ece2d859	165	LWIP_ASSERT("icmp_input: copying to new pbuf failed\n", 0);
mbed714	0:d616ece2d859	166	goto memerr;
mbed714	0:d616ece2d859	167	}
mbed714	0:d616ece2d859	168	iphdr = (struct ip_hdr *)r->payload;
mbed714	0:d616ece2d859	169	/* switch r->payload back to icmp header */
mbed714	0:d616ece2d859	170	if (pbuf_header(r, -hlen)) {
mbed714	0:d616ece2d859	171	LWIP_ASSERT("icmp_input: restoring original p->payload failed\n", 0);
mbed714	0:d616ece2d859	172	goto memerr;
mbed714	0:d616ece2d859	173	}
mbed714	0:d616ece2d859	174	/* free the original p */
mbed714	0:d616ece2d859	175	pbuf_free(p);
mbed714	0:d616ece2d859	176	/* we now have an identical copy of p that has room for link headers */
mbed714	0:d616ece2d859	177	p = r;
mbed714	0:d616ece2d859	178	} else {
mbed714	0:d616ece2d859	179	/* restore p->payload to point to icmp header */
mbed714	0:d616ece2d859	180	if (pbuf_header(p, -(s16_t)(PBUF_IP_HLEN + PBUF_LINK_HLEN))) {
mbed714	0:d616ece2d859	181	LWIP_ASSERT("icmp_input: restoring original p->payload failed\n", 0);
mbed714	0:d616ece2d859	182	goto memerr;
mbed714	0:d616ece2d859	183	}
mbed714	0:d616ece2d859	184	}
mbed714	0:d616ece2d859	185	#endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
mbed714	0:d616ece2d859	186	/* At this point, all checks are OK. */
mbed714	0:d616ece2d859	187	/* We generate an answer by switching the dest and src ip addresses,
mbed714	0:d616ece2d859	188	* setting the icmp type to ECHO_RESPONSE and updating the checksum. */
mbed714	0:d616ece2d859	189	iecho = (struct icmp_echo_hdr *)p->payload;
mbed714	0:d616ece2d859	190	ip_addr_copy(iphdr->src, *ip_current_dest_addr());
mbed714	0:d616ece2d859	191	ip_addr_copy(iphdr->dest, *ip_current_src_addr());
mbed714	0:d616ece2d859	192	ICMPH_TYPE_SET(iecho, ICMP_ER);
mbed714	0:d616ece2d859	193	/* adjust the checksum */
mbed714	0:d616ece2d859	194	if (iecho->chksum >= PP_HTONS(0xffff - (ICMP_ECHO << 8))) {
mbed714	0:d616ece2d859	195	iecho->chksum += PP_HTONS(ICMP_ECHO << 8) + 1;
mbed714	0:d616ece2d859	196	} else {
mbed714	0:d616ece2d859	197	iecho->chksum += PP_HTONS(ICMP_ECHO << 8);
mbed714	0:d616ece2d859	198	}
mbed714	0:d616ece2d859	199
mbed714	0:d616ece2d859	200	/* Set the correct TTL and recalculate the header checksum. */
mbed714	0:d616ece2d859	201	IPH_TTL_SET(iphdr, ICMP_TTL);
mbed714	0:d616ece2d859	202	IPH_CHKSUM_SET(iphdr, 0);
mbed714	0:d616ece2d859	203	#if CHECKSUM_GEN_IP
mbed714	0:d616ece2d859	204	IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
mbed714	0:d616ece2d859	205	#endif /* CHECKSUM_GEN_IP */
mbed714	0:d616ece2d859	206
mbed714	0:d616ece2d859	207	ICMP_STATS_INC(icmp.xmit);
mbed714	0:d616ece2d859	208	/* increase number of messages attempted to send */
mbed714	0:d616ece2d859	209	snmp_inc_icmpoutmsgs();
mbed714	0:d616ece2d859	210	/* increase number of echo replies attempted to send */
mbed714	0:d616ece2d859	211	snmp_inc_icmpoutechoreps();
mbed714	0:d616ece2d859	212
mbed714	0:d616ece2d859	213	if(pbuf_header(p, hlen)) {
mbed714	0:d616ece2d859	214	LWIP_ASSERT("Can't move over header in packet", 0);
mbed714	0:d616ece2d859	215	} else {
mbed714	0:d616ece2d859	216	err_t ret;
mbed714	0:d616ece2d859	217	/* send an ICMP packet, src addr is the dest addr of the curren packet */
mbed714	0:d616ece2d859	218	ret = ip_output_if(p, ip_current_dest_addr(), IP_HDRINCL,
mbed714	0:d616ece2d859	219	ICMP_TTL, 0, IP_PROTO_ICMP, inp);
mbed714	0:d616ece2d859	220	if (ret != ERR_OK) {
mbed714	0:d616ece2d859	221	LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ip_output_if returned an error: %c.\n", ret));
mbed714	0:d616ece2d859	222	}
mbed714	0:d616ece2d859	223	}
mbed714	0:d616ece2d859	224	break;
mbed714	0:d616ece2d859	225	default:
mbed714	0:d616ece2d859	226	LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ICMP type %"S16_F" code %"S16_F" not supported.\n",
mbed714	0:d616ece2d859	227	(s16_t)type, (s16_t)code));
mbed714	0:d616ece2d859	228	ICMP_STATS_INC(icmp.proterr);
mbed714	0:d616ece2d859	229	ICMP_STATS_INC(icmp.drop);
mbed714	0:d616ece2d859	230	}
mbed714	0:d616ece2d859	231	pbuf_free(p);
mbed714	0:d616ece2d859	232	return;
mbed714	0:d616ece2d859	233	lenerr:
mbed714	0:d616ece2d859	234	pbuf_free(p);
mbed714	0:d616ece2d859	235	ICMP_STATS_INC(icmp.lenerr);
mbed714	0:d616ece2d859	236	snmp_inc_icmpinerrors();
mbed714	0:d616ece2d859	237	return;
mbed714	0:d616ece2d859	238	#if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
mbed714	0:d616ece2d859	239	memerr:
mbed714	0:d616ece2d859	240	pbuf_free(p);
mbed714	0:d616ece2d859	241	ICMP_STATS_INC(icmp.err);
mbed714	0:d616ece2d859	242	snmp_inc_icmpinerrors();
mbed714	0:d616ece2d859	243	return;
mbed714	0:d616ece2d859	244	#endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
mbed714	0:d616ece2d859	245	}
mbed714	0:d616ece2d859	246
mbed714	0:d616ece2d859	247	/**
mbed714	0:d616ece2d859	248	* Send an icmp 'destination unreachable' packet, called from ip_input() if
mbed714	0:d616ece2d859	249	* the transport layer protocol is unknown and from udp_input() if the local
mbed714	0:d616ece2d859	250	* port is not bound.
mbed714	0:d616ece2d859	251	*
mbed714	0:d616ece2d859	252	* @param p the input packet for which the 'unreachable' should be sent,
mbed714	0:d616ece2d859	253	* p->payload pointing to the IP header
mbed714	0:d616ece2d859	254	* @param t type of the 'unreachable' packet
mbed714	0:d616ece2d859	255	*/
mbed714	0:d616ece2d859	256	void
mbed714	0:d616ece2d859	257	icmp_dest_unreach(struct pbuf *p, enum icmp_dur_type t)
mbed714	0:d616ece2d859	258	{
mbed714	0:d616ece2d859	259	icmp_send_response(p, ICMP_DUR, t);
mbed714	0:d616ece2d859	260	}
mbed714	0:d616ece2d859	261
mbed714	0:d616ece2d859	262	#if IP_FORWARD \|\| IP_REASSEMBLY
mbed714	0:d616ece2d859	263	/**
mbed714	0:d616ece2d859	264	* Send a 'time exceeded' packet, called from ip_forward() if TTL is 0.
mbed714	0:d616ece2d859	265	*
mbed714	0:d616ece2d859	266	* @param p the input packet for which the 'time exceeded' should be sent,
mbed714	0:d616ece2d859	267	* p->payload pointing to the IP header
mbed714	0:d616ece2d859	268	* @param t type of the 'time exceeded' packet
mbed714	0:d616ece2d859	269	*/
mbed714	0:d616ece2d859	270	void
mbed714	0:d616ece2d859	271	icmp_time_exceeded(struct pbuf *p, enum icmp_te_type t)
mbed714	0:d616ece2d859	272	{
mbed714	0:d616ece2d859	273	icmp_send_response(p, ICMP_TE, t);
mbed714	0:d616ece2d859	274	}
mbed714	0:d616ece2d859	275
mbed714	0:d616ece2d859	276	#endif /* IP_FORWARD \|\| IP_REASSEMBLY */
mbed714	0:d616ece2d859	277
mbed714	0:d616ece2d859	278	/**
mbed714	0:d616ece2d859	279	* Send an icmp packet in response to an incoming packet.
mbed714	0:d616ece2d859	280	*
mbed714	0:d616ece2d859	281	* @param p the input packet for which the 'unreachable' should be sent,
mbed714	0:d616ece2d859	282	* p->payload pointing to the IP header
mbed714	0:d616ece2d859	283	* @param type Type of the ICMP header
mbed714	0:d616ece2d859	284	* @param code Code of the ICMP header
mbed714	0:d616ece2d859	285	*/
mbed714	0:d616ece2d859	286	static void
mbed714	0:d616ece2d859	287	icmp_send_response(struct pbuf *p, u8_t type, u8_t code)
mbed714	0:d616ece2d859	288	{
mbed714	0:d616ece2d859	289	struct pbuf *q;
mbed714	0:d616ece2d859	290	struct ip_hdr *iphdr;
mbed714	0:d616ece2d859	291	/* we can use the echo header here */
mbed714	0:d616ece2d859	292	struct icmp_echo_hdr *icmphdr;
mbed714	0:d616ece2d859	293	ip_addr_t iphdr_src;
mbed714	0:d616ece2d859	294
mbed714	0:d616ece2d859	295	/* ICMP header + IP header + 8 bytes of data */
mbed714	0:d616ece2d859	296	q = pbuf_alloc(PBUF_IP, sizeof(struct icmp_echo_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE,
mbed714	0:d616ece2d859	297	PBUF_RAM);
mbed714	0:d616ece2d859	298	if (q == NULL) {
mbed714	0:d616ece2d859	299	LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded: failed to allocate pbuf for ICMP packet.\n"));
mbed714	0:d616ece2d859	300	return;
mbed714	0:d616ece2d859	301	}
mbed714	0:d616ece2d859	302	LWIP_ASSERT("check that first pbuf can hold icmp message",
mbed714	0:d616ece2d859	303	(q->len >= (sizeof(struct icmp_echo_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE)));
mbed714	0:d616ece2d859	304
mbed714	0:d616ece2d859	305	iphdr = (struct ip_hdr *)p->payload;
mbed714	0:d616ece2d859	306	LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded from "));
mbed714	0:d616ece2d859	307	ip_addr_debug_print(ICMP_DEBUG, &(iphdr->src));
mbed714	0:d616ece2d859	308	LWIP_DEBUGF(ICMP_DEBUG, (" to "));
mbed714	0:d616ece2d859	309	ip_addr_debug_print(ICMP_DEBUG, &(iphdr->dest));
mbed714	0:d616ece2d859	310	LWIP_DEBUGF(ICMP_DEBUG, ("\n"));
mbed714	0:d616ece2d859	311
mbed714	0:d616ece2d859	312	icmphdr = (struct icmp_echo_hdr *)q->payload;
mbed714	0:d616ece2d859	313	icmphdr->type = type;
mbed714	0:d616ece2d859	314	icmphdr->code = code;
mbed714	0:d616ece2d859	315	icmphdr->id = 0;
mbed714	0:d616ece2d859	316	icmphdr->seqno = 0;
mbed714	0:d616ece2d859	317
mbed714	0:d616ece2d859	318	/* copy fields from original packet */
mbed714	0:d616ece2d859	319	SMEMCPY((u8_t )q->payload + sizeof(struct icmp_echo_hdr), (u8_t )p->payload,
mbed714	0:d616ece2d859	320	IP_HLEN + ICMP_DEST_UNREACH_DATASIZE);
mbed714	0:d616ece2d859	321
mbed714	0:d616ece2d859	322	/* calculate checksum */
mbed714	0:d616ece2d859	323	icmphdr->chksum = 0;
mbed714	0:d616ece2d859	324	icmphdr->chksum = inet_chksum(icmphdr, q->len);
mbed714	0:d616ece2d859	325	ICMP_STATS_INC(icmp.xmit);
mbed714	0:d616ece2d859	326	/* increase number of messages attempted to send */
mbed714	0:d616ece2d859	327	snmp_inc_icmpoutmsgs();
mbed714	0:d616ece2d859	328	/* increase number of destination unreachable messages attempted to send */
mbed714	0:d616ece2d859	329	snmp_inc_icmpouttimeexcds();
mbed714	0:d616ece2d859	330	ip_addr_copy(iphdr_src, iphdr->src);
mbed714	0:d616ece2d859	331	ip_output(q, NULL, &iphdr_src, ICMP_TTL, 0, IP_PROTO_ICMP);
mbed714	0:d616ece2d859	332	pbuf_free(q);
mbed714	0:d616ece2d859	333	}
mbed714	0:d616ece2d859	334
mbed714	0:d616ece2d859	335	#endif /* LWIP_ICMP */

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Type:	Library
Created:	18 Sep 2010
Imports:	1
Forks:	0
Commits:	1
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lwip/core/ipv4/icmp.c@0:d616ece2d859, 2010-09-18 (annotated)

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