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Ethernetwebsoc

Dependencies:   C12832_lcd LM75B WebSocketClient mbed-rtos mbed Socket lwip-eth lwip-sys lwip

EthernetInterface/lwip/core/ipv4/icmp.c@0:0ed2a7c7190c, 2013-05-31 (annotated)

Committer:
GordonSin
Date:
Fri May 31 04:09:54 2013 +0000
Revision:
0:0ed2a7c7190c
31/5/2013;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
GordonSin 0:0ed2a7c7190c 1 /**
GordonSin 0:0ed2a7c7190c 2 * @file
GordonSin 0:0ed2a7c7190c 3 * ICMP - Internet Control Message Protocol
GordonSin 0:0ed2a7c7190c 4 *
GordonSin 0:0ed2a7c7190c 5 */
GordonSin 0:0ed2a7c7190c 6
GordonSin 0:0ed2a7c7190c 7 /*
GordonSin 0:0ed2a7c7190c 8 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
GordonSin 0:0ed2a7c7190c 9 * All rights reserved.
GordonSin 0:0ed2a7c7190c 10 *
GordonSin 0:0ed2a7c7190c 11 * Redistribution and use in source and binary forms, with or without modification,
GordonSin 0:0ed2a7c7190c 12 * are permitted provided that the following conditions are met:
GordonSin 0:0ed2a7c7190c 13 *
GordonSin 0:0ed2a7c7190c 14 * 1. Redistributions of source code must retain the above copyright notice,
GordonSin 0:0ed2a7c7190c 15 * this list of conditions and the following disclaimer.
GordonSin 0:0ed2a7c7190c 16 * 2. Redistributions in binary form must reproduce the above copyright notice,
GordonSin 0:0ed2a7c7190c 17 * this list of conditions and the following disclaimer in the documentation
GordonSin 0:0ed2a7c7190c 18 * and/or other materials provided with the distribution.
GordonSin 0:0ed2a7c7190c 19 * 3. The name of the author may not be used to endorse or promote products
GordonSin 0:0ed2a7c7190c 20 * derived from this software without specific prior written permission.
GordonSin 0:0ed2a7c7190c 21 *
GordonSin 0:0ed2a7c7190c 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
GordonSin 0:0ed2a7c7190c 23 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
GordonSin 0:0ed2a7c7190c 24 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
GordonSin 0:0ed2a7c7190c 25 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
GordonSin 0:0ed2a7c7190c 26 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
GordonSin 0:0ed2a7c7190c 27 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
GordonSin 0:0ed2a7c7190c 28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
GordonSin 0:0ed2a7c7190c 29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
GordonSin 0:0ed2a7c7190c 30 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
GordonSin 0:0ed2a7c7190c 31 * OF SUCH DAMAGE.
GordonSin 0:0ed2a7c7190c 32 *
GordonSin 0:0ed2a7c7190c 33 * This file is part of the lwIP TCP/IP stack.
GordonSin 0:0ed2a7c7190c 34 *
GordonSin 0:0ed2a7c7190c 35 * Author: Adam Dunkels <adam@sics.se>
GordonSin 0:0ed2a7c7190c 36 *
GordonSin 0:0ed2a7c7190c 37 */
GordonSin 0:0ed2a7c7190c 38
GordonSin 0:0ed2a7c7190c 39 /* Some ICMP messages should be passed to the transport protocols. This
GordonSin 0:0ed2a7c7190c 40 is not implemented. */
GordonSin 0:0ed2a7c7190c 41
GordonSin 0:0ed2a7c7190c 42 #include "lwip/opt.h"
GordonSin 0:0ed2a7c7190c 43
GordonSin 0:0ed2a7c7190c 44 #if LWIP_ICMP /* don't build if not configured for use in lwipopts.h */
GordonSin 0:0ed2a7c7190c 45
GordonSin 0:0ed2a7c7190c 46 #include "lwip/icmp.h"
GordonSin 0:0ed2a7c7190c 47 #include "lwip/inet_chksum.h"
GordonSin 0:0ed2a7c7190c 48 #include "lwip/ip.h"
GordonSin 0:0ed2a7c7190c 49 #include "lwip/def.h"
GordonSin 0:0ed2a7c7190c 50 #include "lwip/stats.h"
GordonSin 0:0ed2a7c7190c 51 #include "lwip/snmp.h"
GordonSin 0:0ed2a7c7190c 52
GordonSin 0:0ed2a7c7190c 53 #include <string.h>
GordonSin 0:0ed2a7c7190c 54
GordonSin 0:0ed2a7c7190c 55 /** Small optimization: set to 0 if incoming PBUF_POOL pbuf always can be
GordonSin 0:0ed2a7c7190c 56 * used to modify and send a response packet (and to 1 if this is not the case,
GordonSin 0:0ed2a7c7190c 57 * e.g. when link header is stripped of when receiving) */
GordonSin 0:0ed2a7c7190c 58 #ifndef LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
GordonSin 0:0ed2a7c7190c 59 #define LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN 1
GordonSin 0:0ed2a7c7190c 60 #endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
GordonSin 0:0ed2a7c7190c 61
GordonSin 0:0ed2a7c7190c 62 /* The amount of data from the original packet to return in a dest-unreachable */
GordonSin 0:0ed2a7c7190c 63 #define ICMP_DEST_UNREACH_DATASIZE 8
GordonSin 0:0ed2a7c7190c 64
GordonSin 0:0ed2a7c7190c 65 static void icmp_send_response(struct pbuf *p, u8_t type, u8_t code);
GordonSin 0:0ed2a7c7190c 66
GordonSin 0:0ed2a7c7190c 67 /**
GordonSin 0:0ed2a7c7190c 68 * Processes ICMP input packets, called from ip_input().
GordonSin 0:0ed2a7c7190c 69 *
GordonSin 0:0ed2a7c7190c 70 * Currently only processes icmp echo requests and sends
GordonSin 0:0ed2a7c7190c 71 * out the echo response.
GordonSin 0:0ed2a7c7190c 72 *
GordonSin 0:0ed2a7c7190c 73 * @param p the icmp echo request packet, p->payload pointing to the ip header
GordonSin 0:0ed2a7c7190c 74 * @param inp the netif on which this packet was received
GordonSin 0:0ed2a7c7190c 75 */
GordonSin 0:0ed2a7c7190c 76 void
GordonSin 0:0ed2a7c7190c 77 icmp_input(struct pbuf *p, struct netif *inp)
GordonSin 0:0ed2a7c7190c 78 {
GordonSin 0:0ed2a7c7190c 79 u8_t type;
GordonSin 0:0ed2a7c7190c 80 #ifdef LWIP_DEBUG
GordonSin 0:0ed2a7c7190c 81 u8_t code;
GordonSin 0:0ed2a7c7190c 82 #endif /* LWIP_DEBUG */
GordonSin 0:0ed2a7c7190c 83 struct icmp_echo_hdr *iecho;
GordonSin 0:0ed2a7c7190c 84 struct ip_hdr *iphdr;
GordonSin 0:0ed2a7c7190c 85 s16_t hlen;
GordonSin 0:0ed2a7c7190c 86
GordonSin 0:0ed2a7c7190c 87 ICMP_STATS_INC(icmp.recv);
GordonSin 0:0ed2a7c7190c 88 snmp_inc_icmpinmsgs();
GordonSin 0:0ed2a7c7190c 89
GordonSin 0:0ed2a7c7190c 90
GordonSin 0:0ed2a7c7190c 91 iphdr = (struct ip_hdr *)p->payload;
GordonSin 0:0ed2a7c7190c 92 hlen = IPH_HL(iphdr) * 4;
GordonSin 0:0ed2a7c7190c 93 if (pbuf_header(p, -hlen) || (p->tot_len < sizeof(u16_t)*2)) {
GordonSin 0:0ed2a7c7190c 94 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: short ICMP (%"U16_F" bytes) received\n", p->tot_len));
GordonSin 0:0ed2a7c7190c 95 goto lenerr;
GordonSin 0:0ed2a7c7190c 96 }
GordonSin 0:0ed2a7c7190c 97
GordonSin 0:0ed2a7c7190c 98 type = *((u8_t *)p->payload);
GordonSin 0:0ed2a7c7190c 99 #ifdef LWIP_DEBUG
GordonSin 0:0ed2a7c7190c 100 code = *(((u8_t *)p->payload)+1);
GordonSin 0:0ed2a7c7190c 101 #endif /* LWIP_DEBUG */
GordonSin 0:0ed2a7c7190c 102 switch (type) {
GordonSin 0:0ed2a7c7190c 103 case ICMP_ER:
GordonSin 0:0ed2a7c7190c 104 /* This is OK, echo reply might have been parsed by a raw PCB
GordonSin 0:0ed2a7c7190c 105 (as obviously, an echo request has been sent, too). */
GordonSin 0:0ed2a7c7190c 106 break;
GordonSin 0:0ed2a7c7190c 107 case ICMP_ECHO:
GordonSin 0:0ed2a7c7190c 108 #if !LWIP_MULTICAST_PING || !LWIP_BROADCAST_PING
GordonSin 0:0ed2a7c7190c 109 {
GordonSin 0:0ed2a7c7190c 110 int accepted = 1;
GordonSin 0:0ed2a7c7190c 111 #if !LWIP_MULTICAST_PING
GordonSin 0:0ed2a7c7190c 112 /* multicast destination address? */
GordonSin 0:0ed2a7c7190c 113 if (ip_addr_ismulticast(&current_iphdr_dest)) {
GordonSin 0:0ed2a7c7190c 114 accepted = 0;
GordonSin 0:0ed2a7c7190c 115 }
GordonSin 0:0ed2a7c7190c 116 #endif /* LWIP_MULTICAST_PING */
GordonSin 0:0ed2a7c7190c 117 #if !LWIP_BROADCAST_PING
GordonSin 0:0ed2a7c7190c 118 /* broadcast destination address? */
GordonSin 0:0ed2a7c7190c 119 if (ip_addr_isbroadcast(&current_iphdr_dest, inp)) {
GordonSin 0:0ed2a7c7190c 120 accepted = 0;
GordonSin 0:0ed2a7c7190c 121 }
GordonSin 0:0ed2a7c7190c 122 #endif /* LWIP_BROADCAST_PING */
GordonSin 0:0ed2a7c7190c 123 /* broadcast or multicast destination address not acceptd? */
GordonSin 0:0ed2a7c7190c 124 if (!accepted) {
GordonSin 0:0ed2a7c7190c 125 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to multicast or broadcast pings\n"));
GordonSin 0:0ed2a7c7190c 126 ICMP_STATS_INC(icmp.err);
GordonSin 0:0ed2a7c7190c 127 pbuf_free(p);
GordonSin 0:0ed2a7c7190c 128 return;
GordonSin 0:0ed2a7c7190c 129 }
GordonSin 0:0ed2a7c7190c 130 }
GordonSin 0:0ed2a7c7190c 131 #endif /* !LWIP_MULTICAST_PING || !LWIP_BROADCAST_PING */
GordonSin 0:0ed2a7c7190c 132 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ping\n"));
GordonSin 0:0ed2a7c7190c 133 if (p->tot_len < sizeof(struct icmp_echo_hdr)) {
GordonSin 0:0ed2a7c7190c 134 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: bad ICMP echo received\n"));
GordonSin 0:0ed2a7c7190c 135 goto lenerr;
GordonSin 0:0ed2a7c7190c 136 }
GordonSin 0:0ed2a7c7190c 137 if (inet_chksum_pbuf(p) != 0) {
GordonSin 0:0ed2a7c7190c 138 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: checksum failed for received ICMP echo\n"));
GordonSin 0:0ed2a7c7190c 139 pbuf_free(p);
GordonSin 0:0ed2a7c7190c 140 ICMP_STATS_INC(icmp.chkerr);
GordonSin 0:0ed2a7c7190c 141 snmp_inc_icmpinerrors();
GordonSin 0:0ed2a7c7190c 142 return;
GordonSin 0:0ed2a7c7190c 143 }
GordonSin 0:0ed2a7c7190c 144 #if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
GordonSin 0:0ed2a7c7190c 145 if (pbuf_header(p, (PBUF_IP_HLEN + PBUF_LINK_HLEN))) {
GordonSin 0:0ed2a7c7190c 146 /* p is not big enough to contain link headers
GordonSin 0:0ed2a7c7190c 147 * allocate a new one and copy p into it
GordonSin 0:0ed2a7c7190c 148 */
GordonSin 0:0ed2a7c7190c 149 struct pbuf *r;
GordonSin 0:0ed2a7c7190c 150 /* switch p->payload to ip header */
GordonSin 0:0ed2a7c7190c 151 if (pbuf_header(p, hlen)) {
GordonSin 0:0ed2a7c7190c 152 LWIP_ASSERT("icmp_input: moving p->payload to ip header failed\n", 0);
GordonSin 0:0ed2a7c7190c 153 goto memerr;
GordonSin 0:0ed2a7c7190c 154 }
GordonSin 0:0ed2a7c7190c 155 /* allocate new packet buffer with space for link headers */
GordonSin 0:0ed2a7c7190c 156 r = pbuf_alloc(PBUF_LINK, p->tot_len, PBUF_RAM);
GordonSin 0:0ed2a7c7190c 157 if (r == NULL) {
GordonSin 0:0ed2a7c7190c 158 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: allocating new pbuf failed\n"));
GordonSin 0:0ed2a7c7190c 159 goto memerr;
GordonSin 0:0ed2a7c7190c 160 }
GordonSin 0:0ed2a7c7190c 161 LWIP_ASSERT("check that first pbuf can hold struct the ICMP header",
GordonSin 0:0ed2a7c7190c 162 (r->len >= hlen + sizeof(struct icmp_echo_hdr)));
GordonSin 0:0ed2a7c7190c 163 /* copy the whole packet including ip header */
GordonSin 0:0ed2a7c7190c 164 if (pbuf_copy(r, p) != ERR_OK) {
GordonSin 0:0ed2a7c7190c 165 LWIP_ASSERT("icmp_input: copying to new pbuf failed\n", 0);
GordonSin 0:0ed2a7c7190c 166 goto memerr;
GordonSin 0:0ed2a7c7190c 167 }
GordonSin 0:0ed2a7c7190c 168 iphdr = (struct ip_hdr *)r->payload;
GordonSin 0:0ed2a7c7190c 169 /* switch r->payload back to icmp header */
GordonSin 0:0ed2a7c7190c 170 if (pbuf_header(r, -hlen)) {
GordonSin 0:0ed2a7c7190c 171 LWIP_ASSERT("icmp_input: restoring original p->payload failed\n", 0);
GordonSin 0:0ed2a7c7190c 172 goto memerr;
GordonSin 0:0ed2a7c7190c 173 }
GordonSin 0:0ed2a7c7190c 174 /* free the original p */
GordonSin 0:0ed2a7c7190c 175 pbuf_free(p);
GordonSin 0:0ed2a7c7190c 176 /* we now have an identical copy of p that has room for link headers */
GordonSin 0:0ed2a7c7190c 177 p = r;
GordonSin 0:0ed2a7c7190c 178 } else {
GordonSin 0:0ed2a7c7190c 179 /* restore p->payload to point to icmp header */
GordonSin 0:0ed2a7c7190c 180 if (pbuf_header(p, -(s16_t)(PBUF_IP_HLEN + PBUF_LINK_HLEN))) {
GordonSin 0:0ed2a7c7190c 181 LWIP_ASSERT("icmp_input: restoring original p->payload failed\n", 0);
GordonSin 0:0ed2a7c7190c 182 goto memerr;
GordonSin 0:0ed2a7c7190c 183 }
GordonSin 0:0ed2a7c7190c 184 }
GordonSin 0:0ed2a7c7190c 185 #endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
GordonSin 0:0ed2a7c7190c 186 /* At this point, all checks are OK. */
GordonSin 0:0ed2a7c7190c 187 /* We generate an answer by switching the dest and src ip addresses,
GordonSin 0:0ed2a7c7190c 188 * setting the icmp type to ECHO_RESPONSE and updating the checksum. */
GordonSin 0:0ed2a7c7190c 189 iecho = (struct icmp_echo_hdr *)p->payload;
GordonSin 0:0ed2a7c7190c 190 ip_addr_copy(iphdr->src, *ip_current_dest_addr());
GordonSin 0:0ed2a7c7190c 191 ip_addr_copy(iphdr->dest, *ip_current_src_addr());
GordonSin 0:0ed2a7c7190c 192 ICMPH_TYPE_SET(iecho, ICMP_ER);
GordonSin 0:0ed2a7c7190c 193 /* adjust the checksum */
GordonSin 0:0ed2a7c7190c 194 if (iecho->chksum >= PP_HTONS(0xffffU - (ICMP_ECHO << 8))) {
GordonSin 0:0ed2a7c7190c 195 iecho->chksum += PP_HTONS(ICMP_ECHO << 8) + 1;
GordonSin 0:0ed2a7c7190c 196 } else {
GordonSin 0:0ed2a7c7190c 197 iecho->chksum += PP_HTONS(ICMP_ECHO << 8);
GordonSin 0:0ed2a7c7190c 198 }
GordonSin 0:0ed2a7c7190c 199
GordonSin 0:0ed2a7c7190c 200 /* Set the correct TTL and recalculate the header checksum. */
GordonSin 0:0ed2a7c7190c 201 IPH_TTL_SET(iphdr, ICMP_TTL);
GordonSin 0:0ed2a7c7190c 202 IPH_CHKSUM_SET(iphdr, 0);
GordonSin 0:0ed2a7c7190c 203 #if CHECKSUM_GEN_IP
GordonSin 0:0ed2a7c7190c 204 IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
GordonSin 0:0ed2a7c7190c 205 #endif /* CHECKSUM_GEN_IP */
GordonSin 0:0ed2a7c7190c 206
GordonSin 0:0ed2a7c7190c 207 ICMP_STATS_INC(icmp.xmit);
GordonSin 0:0ed2a7c7190c 208 /* increase number of messages attempted to send */
GordonSin 0:0ed2a7c7190c 209 snmp_inc_icmpoutmsgs();
GordonSin 0:0ed2a7c7190c 210 /* increase number of echo replies attempted to send */
GordonSin 0:0ed2a7c7190c 211 snmp_inc_icmpoutechoreps();
GordonSin 0:0ed2a7c7190c 212
GordonSin 0:0ed2a7c7190c 213 if(pbuf_header(p, hlen)) {
GordonSin 0:0ed2a7c7190c 214 LWIP_ASSERT("Can't move over header in packet", 0);
GordonSin 0:0ed2a7c7190c 215 } else {
GordonSin 0:0ed2a7c7190c 216 err_t ret;
GordonSin 0:0ed2a7c7190c 217 /* send an ICMP packet, src addr is the dest addr of the curren packet */
GordonSin 0:0ed2a7c7190c 218 ret = ip_output_if(p, ip_current_dest_addr(), IP_HDRINCL,
GordonSin 0:0ed2a7c7190c 219 ICMP_TTL, 0, IP_PROTO_ICMP, inp);
GordonSin 0:0ed2a7c7190c 220 if (ret != ERR_OK) {
GordonSin 0:0ed2a7c7190c 221 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ip_output_if returned an error: %c.\n", ret));
GordonSin 0:0ed2a7c7190c 222 }
GordonSin 0:0ed2a7c7190c 223 }
GordonSin 0:0ed2a7c7190c 224 break;
GordonSin 0:0ed2a7c7190c 225 default:
GordonSin 0:0ed2a7c7190c 226 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ICMP type %"S16_F" code %"S16_F" not supported.\n",
GordonSin 0:0ed2a7c7190c 227 (s16_t)type, (s16_t)code));
GordonSin 0:0ed2a7c7190c 228 ICMP_STATS_INC(icmp.proterr);
GordonSin 0:0ed2a7c7190c 229 ICMP_STATS_INC(icmp.drop);
GordonSin 0:0ed2a7c7190c 230 }
GordonSin 0:0ed2a7c7190c 231 pbuf_free(p);
GordonSin 0:0ed2a7c7190c 232 return;
GordonSin 0:0ed2a7c7190c 233 lenerr:
GordonSin 0:0ed2a7c7190c 234 pbuf_free(p);
GordonSin 0:0ed2a7c7190c 235 ICMP_STATS_INC(icmp.lenerr);
GordonSin 0:0ed2a7c7190c 236 snmp_inc_icmpinerrors();
GordonSin 0:0ed2a7c7190c 237 return;
GordonSin 0:0ed2a7c7190c 238 #if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
GordonSin 0:0ed2a7c7190c 239 memerr:
GordonSin 0:0ed2a7c7190c 240 pbuf_free(p);
GordonSin 0:0ed2a7c7190c 241 ICMP_STATS_INC(icmp.err);
GordonSin 0:0ed2a7c7190c 242 snmp_inc_icmpinerrors();
GordonSin 0:0ed2a7c7190c 243 return;
GordonSin 0:0ed2a7c7190c 244 #endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
GordonSin 0:0ed2a7c7190c 245 }
GordonSin 0:0ed2a7c7190c 246
GordonSin 0:0ed2a7c7190c 247 /**
GordonSin 0:0ed2a7c7190c 248 * Send an icmp 'destination unreachable' packet, called from ip_input() if
GordonSin 0:0ed2a7c7190c 249 * the transport layer protocol is unknown and from udp_input() if the local
GordonSin 0:0ed2a7c7190c 250 * port is not bound.
GordonSin 0:0ed2a7c7190c 251 *
GordonSin 0:0ed2a7c7190c 252 * @param p the input packet for which the 'unreachable' should be sent,
GordonSin 0:0ed2a7c7190c 253 * p->payload pointing to the IP header
GordonSin 0:0ed2a7c7190c 254 * @param t type of the 'unreachable' packet
GordonSin 0:0ed2a7c7190c 255 */
GordonSin 0:0ed2a7c7190c 256 void
GordonSin 0:0ed2a7c7190c 257 icmp_dest_unreach(struct pbuf *p, enum icmp_dur_type t)
GordonSin 0:0ed2a7c7190c 258 {
GordonSin 0:0ed2a7c7190c 259 icmp_send_response(p, ICMP_DUR, t);
GordonSin 0:0ed2a7c7190c 260 }
GordonSin 0:0ed2a7c7190c 261
GordonSin 0:0ed2a7c7190c 262 #if IP_FORWARD || IP_REASSEMBLY
GordonSin 0:0ed2a7c7190c 263 /**
GordonSin 0:0ed2a7c7190c 264 * Send a 'time exceeded' packet, called from ip_forward() if TTL is 0.
GordonSin 0:0ed2a7c7190c 265 *
GordonSin 0:0ed2a7c7190c 266 * @param p the input packet for which the 'time exceeded' should be sent,
GordonSin 0:0ed2a7c7190c 267 * p->payload pointing to the IP header
GordonSin 0:0ed2a7c7190c 268 * @param t type of the 'time exceeded' packet
GordonSin 0:0ed2a7c7190c 269 */
GordonSin 0:0ed2a7c7190c 270 void
GordonSin 0:0ed2a7c7190c 271 icmp_time_exceeded(struct pbuf *p, enum icmp_te_type t)
GordonSin 0:0ed2a7c7190c 272 {
GordonSin 0:0ed2a7c7190c 273 icmp_send_response(p, ICMP_TE, t);
GordonSin 0:0ed2a7c7190c 274 }
GordonSin 0:0ed2a7c7190c 275
GordonSin 0:0ed2a7c7190c 276 #endif /* IP_FORWARD || IP_REASSEMBLY */
GordonSin 0:0ed2a7c7190c 277
GordonSin 0:0ed2a7c7190c 278 /**
GordonSin 0:0ed2a7c7190c 279 * Send an icmp packet in response to an incoming packet.
GordonSin 0:0ed2a7c7190c 280 *
GordonSin 0:0ed2a7c7190c 281 * @param p the input packet for which the 'unreachable' should be sent,
GordonSin 0:0ed2a7c7190c 282 * p->payload pointing to the IP header
GordonSin 0:0ed2a7c7190c 283 * @param type Type of the ICMP header
GordonSin 0:0ed2a7c7190c 284 * @param code Code of the ICMP header
GordonSin 0:0ed2a7c7190c 285 */
GordonSin 0:0ed2a7c7190c 286 static void
GordonSin 0:0ed2a7c7190c 287 icmp_send_response(struct pbuf *p, u8_t type, u8_t code)
GordonSin 0:0ed2a7c7190c 288 {
GordonSin 0:0ed2a7c7190c 289 struct pbuf *q;
GordonSin 0:0ed2a7c7190c 290 struct ip_hdr *iphdr;
GordonSin 0:0ed2a7c7190c 291 /* we can use the echo header here */
GordonSin 0:0ed2a7c7190c 292 struct icmp_echo_hdr *icmphdr;
GordonSin 0:0ed2a7c7190c 293 ip_addr_t iphdr_src;
GordonSin 0:0ed2a7c7190c 294
GordonSin 0:0ed2a7c7190c 295 /* ICMP header + IP header + 8 bytes of data */
GordonSin 0:0ed2a7c7190c 296 q = pbuf_alloc(PBUF_IP, sizeof(struct icmp_echo_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE,
GordonSin 0:0ed2a7c7190c 297 PBUF_RAM);
GordonSin 0:0ed2a7c7190c 298 if (q == NULL) {
GordonSin 0:0ed2a7c7190c 299 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded: failed to allocate pbuf for ICMP packet.\n"));
GordonSin 0:0ed2a7c7190c 300 return;
GordonSin 0:0ed2a7c7190c 301 }
GordonSin 0:0ed2a7c7190c 302 LWIP_ASSERT("check that first pbuf can hold icmp message",
GordonSin 0:0ed2a7c7190c 303 (q->len >= (sizeof(struct icmp_echo_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE)));
GordonSin 0:0ed2a7c7190c 304
GordonSin 0:0ed2a7c7190c 305 iphdr = (struct ip_hdr *)p->payload;
GordonSin 0:0ed2a7c7190c 306 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded from "));
GordonSin 0:0ed2a7c7190c 307 ip_addr_debug_print(ICMP_DEBUG, &(iphdr->src));
GordonSin 0:0ed2a7c7190c 308 LWIP_DEBUGF(ICMP_DEBUG, (" to "));
GordonSin 0:0ed2a7c7190c 309 ip_addr_debug_print(ICMP_DEBUG, &(iphdr->dest));
GordonSin 0:0ed2a7c7190c 310 LWIP_DEBUGF(ICMP_DEBUG, ("\n"));
GordonSin 0:0ed2a7c7190c 311
GordonSin 0:0ed2a7c7190c 312 icmphdr = (struct icmp_echo_hdr *)q->payload;
GordonSin 0:0ed2a7c7190c 313 icmphdr->type = type;
GordonSin 0:0ed2a7c7190c 314 icmphdr->code = code;
GordonSin 0:0ed2a7c7190c 315 icmphdr->id = 0;
GordonSin 0:0ed2a7c7190c 316 icmphdr->seqno = 0;
GordonSin 0:0ed2a7c7190c 317
GordonSin 0:0ed2a7c7190c 318 /* copy fields from original packet */
GordonSin 0:0ed2a7c7190c 319 SMEMCPY((u8_t *)q->payload + sizeof(struct icmp_echo_hdr), (u8_t *)p->payload,
GordonSin 0:0ed2a7c7190c 320 IP_HLEN + ICMP_DEST_UNREACH_DATASIZE);
GordonSin 0:0ed2a7c7190c 321
GordonSin 0:0ed2a7c7190c 322 /* calculate checksum */
GordonSin 0:0ed2a7c7190c 323 icmphdr->chksum = 0;
GordonSin 0:0ed2a7c7190c 324 icmphdr->chksum = inet_chksum(icmphdr, q->len);
GordonSin 0:0ed2a7c7190c 325 ICMP_STATS_INC(icmp.xmit);
GordonSin 0:0ed2a7c7190c 326 /* increase number of messages attempted to send */
GordonSin 0:0ed2a7c7190c 327 snmp_inc_icmpoutmsgs();
GordonSin 0:0ed2a7c7190c 328 /* increase number of destination unreachable messages attempted to send */
GordonSin 0:0ed2a7c7190c 329 snmp_inc_icmpouttimeexcds();
GordonSin 0:0ed2a7c7190c 330 ip_addr_copy(iphdr_src, iphdr->src);
GordonSin 0:0ed2a7c7190c 331 ip_output(q, NULL, &iphdr_src, ICMP_TTL, 0, IP_PROTO_ICMP);
GordonSin 0:0ed2a7c7190c 332 pbuf_free(q);
GordonSin 0:0ed2a7c7190c 333 }
GordonSin 0:0ed2a7c7190c 334
GordonSin 0:0ed2a7c7190c 335 #endif /* LWIP_ICMP */