Mihail Stoyanov / HTTPServer

My fork of the HTTPServer (working)

Dependents:   DGWWebServer LAN2

Core/lwIP/core/ipv4/icmp.c@0:7a64fbb4069d, 2012-08-06 (annotated)

Committer:
screamer
Date:
Mon Aug 06 09:23:14 2012 +0000
Revision:
0:7a64fbb4069d
[mbed] converted /DGWWebServer/HTTPServer

Who changed what in which revision?

UserRevisionLine numberNew contents of line
screamer 0:7a64fbb4069d 1 /**
screamer 0:7a64fbb4069d 2 * @file
screamer 0:7a64fbb4069d 3 * ICMP - Internet Control Message Protocol
screamer 0:7a64fbb4069d 4 *
screamer 0:7a64fbb4069d 5 */
screamer 0:7a64fbb4069d 6
screamer 0:7a64fbb4069d 7 /*
screamer 0:7a64fbb4069d 8 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
screamer 0:7a64fbb4069d 9 * All rights reserved.
screamer 0:7a64fbb4069d 10 *
screamer 0:7a64fbb4069d 11 * Redistribution and use in source and binary forms, with or without modification,
screamer 0:7a64fbb4069d 12 * are permitted provided that the following conditions are met:
screamer 0:7a64fbb4069d 13 *
screamer 0:7a64fbb4069d 14 * 1. Redistributions of source code must retain the above copyright notice,
screamer 0:7a64fbb4069d 15 * this list of conditions and the following disclaimer.
screamer 0:7a64fbb4069d 16 * 2. Redistributions in binary form must reproduce the above copyright notice,
screamer 0:7a64fbb4069d 17 * this list of conditions and the following disclaimer in the documentation
screamer 0:7a64fbb4069d 18 * and/or other materials provided with the distribution.
screamer 0:7a64fbb4069d 19 * 3. The name of the author may not be used to endorse or promote products
screamer 0:7a64fbb4069d 20 * derived from this software without specific prior written permission.
screamer 0:7a64fbb4069d 21 *
screamer 0:7a64fbb4069d 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
screamer 0:7a64fbb4069d 23 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
screamer 0:7a64fbb4069d 24 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
screamer 0:7a64fbb4069d 25 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
screamer 0:7a64fbb4069d 26 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
screamer 0:7a64fbb4069d 27 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
screamer 0:7a64fbb4069d 28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
screamer 0:7a64fbb4069d 29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
screamer 0:7a64fbb4069d 30 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
screamer 0:7a64fbb4069d 31 * OF SUCH DAMAGE.
screamer 0:7a64fbb4069d 32 *
screamer 0:7a64fbb4069d 33 * This file is part of the lwIP TCP/IP stack.
screamer 0:7a64fbb4069d 34 *
screamer 0:7a64fbb4069d 35 * Author: Adam Dunkels <adam@sics.se>
screamer 0:7a64fbb4069d 36 *
screamer 0:7a64fbb4069d 37 */
screamer 0:7a64fbb4069d 38
screamer 0:7a64fbb4069d 39 /* Some ICMP messages should be passed to the transport protocols. This
screamer 0:7a64fbb4069d 40 is not implemented. */
screamer 0:7a64fbb4069d 41
screamer 0:7a64fbb4069d 42 #include "lwip/opt.h"
screamer 0:7a64fbb4069d 43
screamer 0:7a64fbb4069d 44 #if LWIP_ICMP /* don't build if not configured for use in lwipopts.h */
screamer 0:7a64fbb4069d 45
screamer 0:7a64fbb4069d 46 #include "lwip/icmp.h"
screamer 0:7a64fbb4069d 47 #include "lwip/inet.h"
screamer 0:7a64fbb4069d 48 #include "lwip/inet_chksum.h"
screamer 0:7a64fbb4069d 49 #include "lwip/ip.h"
screamer 0:7a64fbb4069d 50 #include "lwip/def.h"
screamer 0:7a64fbb4069d 51 #include "lwip/stats.h"
screamer 0:7a64fbb4069d 52 #include "lwip/snmp.h"
screamer 0:7a64fbb4069d 53
screamer 0:7a64fbb4069d 54 #include <string.h>
screamer 0:7a64fbb4069d 55
screamer 0:7a64fbb4069d 56 /* The amount of data from the original packet to return in a dest-unreachable */
screamer 0:7a64fbb4069d 57 #define ICMP_DEST_UNREACH_DATASIZE 8
screamer 0:7a64fbb4069d 58
screamer 0:7a64fbb4069d 59 /**
screamer 0:7a64fbb4069d 60 * Processes ICMP input packets, called from ip_input().
screamer 0:7a64fbb4069d 61 *
screamer 0:7a64fbb4069d 62 * Currently only processes icmp echo requests and sends
screamer 0:7a64fbb4069d 63 * out the echo response.
screamer 0:7a64fbb4069d 64 *
screamer 0:7a64fbb4069d 65 * @param p the icmp echo request packet, p->payload pointing to the ip header
screamer 0:7a64fbb4069d 66 * @param inp the netif on which this packet was received
screamer 0:7a64fbb4069d 67 */
screamer 0:7a64fbb4069d 68 void
screamer 0:7a64fbb4069d 69 icmp_input(struct pbuf *p, struct netif *inp)
screamer 0:7a64fbb4069d 70 {
screamer 0:7a64fbb4069d 71 u8_t type;
screamer 0:7a64fbb4069d 72 #ifdef LWIP_DEBUG
screamer 0:7a64fbb4069d 73 u8_t code;
screamer 0:7a64fbb4069d 74 #endif /* LWIP_DEBUG */
screamer 0:7a64fbb4069d 75 struct icmp_echo_hdr *iecho;
screamer 0:7a64fbb4069d 76 struct ip_hdr *iphdr;
screamer 0:7a64fbb4069d 77 struct ip_addr tmpaddr;
screamer 0:7a64fbb4069d 78 s16_t hlen;
screamer 0:7a64fbb4069d 79
screamer 0:7a64fbb4069d 80 ICMP_STATS_INC(icmp.recv);
screamer 0:7a64fbb4069d 81 snmp_inc_icmpinmsgs();
screamer 0:7a64fbb4069d 82
screamer 0:7a64fbb4069d 83
screamer 0:7a64fbb4069d 84 iphdr = (struct ip_hdr *)(p->payload); // static_cast<struct ip_hdr *>(x)
screamer 0:7a64fbb4069d 85 hlen = IPH_HL(iphdr) * 4;
screamer 0:7a64fbb4069d 86 if (pbuf_header(p, -hlen) || (p->tot_len < sizeof(u16_t)*2)) {
screamer 0:7a64fbb4069d 87 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: short ICMP (%"U16_F" bytes) received\n", p->tot_len));
screamer 0:7a64fbb4069d 88 goto lenerr;
screamer 0:7a64fbb4069d 89 }
screamer 0:7a64fbb4069d 90
screamer 0:7a64fbb4069d 91 type = *((u8_t *)p->payload);
screamer 0:7a64fbb4069d 92 #ifdef LWIP_DEBUG
screamer 0:7a64fbb4069d 93 code = *(((u8_t *)p->payload)+1);
screamer 0:7a64fbb4069d 94 #endif /* LWIP_DEBUG */
screamer 0:7a64fbb4069d 95 switch (type) {
screamer 0:7a64fbb4069d 96 case ICMP_ECHO:
screamer 0:7a64fbb4069d 97 #if !LWIP_MULTICAST_PING || !LWIP_BROADCAST_PING
screamer 0:7a64fbb4069d 98 {
screamer 0:7a64fbb4069d 99 int accepted = 1;
screamer 0:7a64fbb4069d 100 #if !LWIP_MULTICAST_PING
screamer 0:7a64fbb4069d 101 /* multicast destination address? */
screamer 0:7a64fbb4069d 102 if (ip_addr_ismulticast(&(iphdr->dest))) {
screamer 0:7a64fbb4069d 103 accepted = 0;
screamer 0:7a64fbb4069d 104 }
screamer 0:7a64fbb4069d 105 #endif /* LWIP_MULTICAST_PING */
screamer 0:7a64fbb4069d 106 #if !LWIP_BROADCAST_PING
screamer 0:7a64fbb4069d 107 /* broadcast destination address? */
screamer 0:7a64fbb4069d 108 if (ip_addr_isbroadcast(&(iphdr->dest), inp)) {
screamer 0:7a64fbb4069d 109 accepted = 0;
screamer 0:7a64fbb4069d 110 }
screamer 0:7a64fbb4069d 111 #endif /* LWIP_BROADCAST_PING */
screamer 0:7a64fbb4069d 112 /* broadcast or multicast destination address not acceptd? */
screamer 0:7a64fbb4069d 113 if (!accepted) {
screamer 0:7a64fbb4069d 114 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to multicast or broadcast pings\n"));
screamer 0:7a64fbb4069d 115 ICMP_STATS_INC(icmp.err);
screamer 0:7a64fbb4069d 116 pbuf_free(p);
screamer 0:7a64fbb4069d 117 return;
screamer 0:7a64fbb4069d 118 }
screamer 0:7a64fbb4069d 119 }
screamer 0:7a64fbb4069d 120 #endif /* !LWIP_MULTICAST_PING || !LWIP_BROADCAST_PING */
screamer 0:7a64fbb4069d 121 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ping\n"));
screamer 0:7a64fbb4069d 122 if (p->tot_len < sizeof(struct icmp_echo_hdr)) {
screamer 0:7a64fbb4069d 123 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: bad ICMP echo received\n"));
screamer 0:7a64fbb4069d 124 goto lenerr;
screamer 0:7a64fbb4069d 125 }
screamer 0:7a64fbb4069d 126 if (inet_chksum_pbuf(p) != 0) {
screamer 0:7a64fbb4069d 127 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: checksum failed for received ICMP echo\n"));
screamer 0:7a64fbb4069d 128 pbuf_free(p);
screamer 0:7a64fbb4069d 129 ICMP_STATS_INC(icmp.chkerr);
screamer 0:7a64fbb4069d 130 snmp_inc_icmpinerrors();
screamer 0:7a64fbb4069d 131 return;
screamer 0:7a64fbb4069d 132 }
screamer 0:7a64fbb4069d 133 if (pbuf_header(p, (PBUF_IP_HLEN + PBUF_LINK_HLEN))) {
screamer 0:7a64fbb4069d 134 /* p is not big enough to contain link headers
screamer 0:7a64fbb4069d 135 * allocate a new one and copy p into it
screamer 0:7a64fbb4069d 136 */
screamer 0:7a64fbb4069d 137 struct pbuf *r;
screamer 0:7a64fbb4069d 138 /* switch p->payload to ip header */
screamer 0:7a64fbb4069d 139 if (pbuf_header(p, hlen)) {
screamer 0:7a64fbb4069d 140 LWIP_ASSERT("icmp_input: moving p->payload to ip header failed\n", 0);
screamer 0:7a64fbb4069d 141 goto memerr;
screamer 0:7a64fbb4069d 142 }
screamer 0:7a64fbb4069d 143 /* allocate new packet buffer with space for link headers */
screamer 0:7a64fbb4069d 144 r = pbuf_alloc(PBUF_LINK, p->tot_len, PBUF_RAM);
screamer 0:7a64fbb4069d 145 if (r == NULL) {
screamer 0:7a64fbb4069d 146 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: allocating new pbuf failed\n"));
screamer 0:7a64fbb4069d 147 goto memerr;
screamer 0:7a64fbb4069d 148 }
screamer 0:7a64fbb4069d 149 LWIP_ASSERT("check that first pbuf can hold struct the ICMP header",
screamer 0:7a64fbb4069d 150 (r->len >= hlen + sizeof(struct icmp_echo_hdr)));
screamer 0:7a64fbb4069d 151 /* copy the whole packet including ip header */
screamer 0:7a64fbb4069d 152 if (pbuf_copy(r, p) != ERR_OK) {
screamer 0:7a64fbb4069d 153 LWIP_ASSERT("icmp_input: copying to new pbuf failed\n", 0);
screamer 0:7a64fbb4069d 154 goto memerr;
screamer 0:7a64fbb4069d 155 }
screamer 0:7a64fbb4069d 156 iphdr = (struct ip_hdr *)(r->payload); // static_cast<struct ip_hdr *>(x)
screamer 0:7a64fbb4069d 157 /* switch r->payload back to icmp header */
screamer 0:7a64fbb4069d 158 if (pbuf_header(r, -hlen)) {
screamer 0:7a64fbb4069d 159 LWIP_ASSERT("icmp_input: restoring original p->payload failed\n", 0);
screamer 0:7a64fbb4069d 160 goto memerr;
screamer 0:7a64fbb4069d 161 }
screamer 0:7a64fbb4069d 162 /* free the original p */
screamer 0:7a64fbb4069d 163 pbuf_free(p);
screamer 0:7a64fbb4069d 164 /* we now have an identical copy of p that has room for link headers */
screamer 0:7a64fbb4069d 165 p = r;
screamer 0:7a64fbb4069d 166 } else {
screamer 0:7a64fbb4069d 167 /* restore p->payload to point to icmp header */
screamer 0:7a64fbb4069d 168 if (pbuf_header(p, -(s16_t)(PBUF_IP_HLEN + PBUF_LINK_HLEN))) {
screamer 0:7a64fbb4069d 169 LWIP_ASSERT("icmp_input: restoring original p->payload failed\n", 0);
screamer 0:7a64fbb4069d 170 goto memerr;
screamer 0:7a64fbb4069d 171 }
screamer 0:7a64fbb4069d 172 }
screamer 0:7a64fbb4069d 173 /* At this point, all checks are OK. */
screamer 0:7a64fbb4069d 174 /* We generate an answer by switching the dest and src ip addresses,
screamer 0:7a64fbb4069d 175 * setting the icmp type to ECHO_RESPONSE and updating the checksum. */
screamer 0:7a64fbb4069d 176 iecho = (struct icmp_echo_hdr *)(p->payload); // static_cast<struct icmp_echo_hdr *>(x)
screamer 0:7a64fbb4069d 177 tmpaddr.addr = iphdr->src.addr;
screamer 0:7a64fbb4069d 178 iphdr->src.addr = iphdr->dest.addr;
screamer 0:7a64fbb4069d 179 iphdr->dest.addr = tmpaddr.addr;
screamer 0:7a64fbb4069d 180 ICMPH_TYPE_SET(iecho, ICMP_ER);
screamer 0:7a64fbb4069d 181 /* adjust the checksum */
screamer 0:7a64fbb4069d 182 if (iecho->chksum >= htons(0xffff - (ICMP_ECHO << 8))) {
screamer 0:7a64fbb4069d 183 iecho->chksum += htons(ICMP_ECHO << 8) + 1;
screamer 0:7a64fbb4069d 184 } else {
screamer 0:7a64fbb4069d 185 iecho->chksum += htons(ICMP_ECHO << 8);
screamer 0:7a64fbb4069d 186 }
screamer 0:7a64fbb4069d 187
screamer 0:7a64fbb4069d 188 /* Set the correct TTL and recalculate the header checksum. */
screamer 0:7a64fbb4069d 189 IPH_TTL_SET(iphdr, ICMP_TTL);
screamer 0:7a64fbb4069d 190 IPH_CHKSUM_SET(iphdr, 0);
screamer 0:7a64fbb4069d 191 #if CHECKSUM_GEN_IP
screamer 0:7a64fbb4069d 192 IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
screamer 0:7a64fbb4069d 193 #endif /* CHECKSUM_GEN_IP */
screamer 0:7a64fbb4069d 194
screamer 0:7a64fbb4069d 195 ICMP_STATS_INC(icmp.xmit);
screamer 0:7a64fbb4069d 196 /* increase number of messages attempted to send */
screamer 0:7a64fbb4069d 197 snmp_inc_icmpoutmsgs();
screamer 0:7a64fbb4069d 198 /* increase number of echo replies attempted to send */
screamer 0:7a64fbb4069d 199 snmp_inc_icmpoutechoreps();
screamer 0:7a64fbb4069d 200
screamer 0:7a64fbb4069d 201 if(pbuf_header(p, hlen)) {
screamer 0:7a64fbb4069d 202 LWIP_ASSERT("Can't move over header in packet", 0);
screamer 0:7a64fbb4069d 203 } else {
screamer 0:7a64fbb4069d 204 err_t ret;
screamer 0:7a64fbb4069d 205 struct ip_addr iphdrsrc; // XXX: __packed hack
screamer 0:7a64fbb4069d 206 iphdrsrc.addr = iphdr->src.addr;
screamer 0:7a64fbb4069d 207 ret = ip_output_if(p, &(iphdrsrc), IP_HDRINCL,
screamer 0:7a64fbb4069d 208 ICMP_TTL, 0, IP_PROTO_ICMP, inp);
screamer 0:7a64fbb4069d 209 if (ret != ERR_OK) {
screamer 0:7a64fbb4069d 210 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ip_output_if returned an error: %c.\n", ret));
screamer 0:7a64fbb4069d 211 }
screamer 0:7a64fbb4069d 212 }
screamer 0:7a64fbb4069d 213 break;
screamer 0:7a64fbb4069d 214 default:
screamer 0:7a64fbb4069d 215 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ICMP type %"S16_F" code %"S16_F" not supported.\n",
screamer 0:7a64fbb4069d 216 (s16_t)type, (s16_t)code));
screamer 0:7a64fbb4069d 217 ICMP_STATS_INC(icmp.proterr);
screamer 0:7a64fbb4069d 218 ICMP_STATS_INC(icmp.drop);
screamer 0:7a64fbb4069d 219 }
screamer 0:7a64fbb4069d 220 pbuf_free(p);
screamer 0:7a64fbb4069d 221 return;
screamer 0:7a64fbb4069d 222 lenerr:
screamer 0:7a64fbb4069d 223 pbuf_free(p);
screamer 0:7a64fbb4069d 224 ICMP_STATS_INC(icmp.lenerr);
screamer 0:7a64fbb4069d 225 snmp_inc_icmpinerrors();
screamer 0:7a64fbb4069d 226 return;
screamer 0:7a64fbb4069d 227 memerr:
screamer 0:7a64fbb4069d 228 pbuf_free(p);
screamer 0:7a64fbb4069d 229 ICMP_STATS_INC(icmp.err);
screamer 0:7a64fbb4069d 230 snmp_inc_icmpinerrors();
screamer 0:7a64fbb4069d 231 return;
screamer 0:7a64fbb4069d 232 }
screamer 0:7a64fbb4069d 233
screamer 0:7a64fbb4069d 234 /**
screamer 0:7a64fbb4069d 235 * Send an icmp 'destination unreachable' packet, called from ip_input() if
screamer 0:7a64fbb4069d 236 * the transport layer protocol is unknown and from udp_input() if the local
screamer 0:7a64fbb4069d 237 * port is not bound.
screamer 0:7a64fbb4069d 238 *
screamer 0:7a64fbb4069d 239 * @param p the input packet for which the 'unreachable' should be sent,
screamer 0:7a64fbb4069d 240 * p->payload pointing to the IP header
screamer 0:7a64fbb4069d 241 * @param t type of the 'unreachable' packet
screamer 0:7a64fbb4069d 242 */
screamer 0:7a64fbb4069d 243 void
screamer 0:7a64fbb4069d 244 icmp_dest_unreach(struct pbuf *p, enum icmp_dur_type t)
screamer 0:7a64fbb4069d 245 {
screamer 0:7a64fbb4069d 246 struct pbuf *q;
screamer 0:7a64fbb4069d 247 struct ip_hdr *iphdr;
screamer 0:7a64fbb4069d 248 struct icmp_dur_hdr *idur;
screamer 0:7a64fbb4069d 249
screamer 0:7a64fbb4069d 250 /* ICMP header + IP header + 8 bytes of data */
screamer 0:7a64fbb4069d 251 q = pbuf_alloc(PBUF_IP, sizeof(struct icmp_dur_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE,
screamer 0:7a64fbb4069d 252 PBUF_RAM);
screamer 0:7a64fbb4069d 253 if (q == NULL) {
screamer 0:7a64fbb4069d 254 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_dest_unreach: failed to allocate pbuf for ICMP packet.\n"));
screamer 0:7a64fbb4069d 255 return;
screamer 0:7a64fbb4069d 256 }
screamer 0:7a64fbb4069d 257 LWIP_ASSERT("check that first pbuf can hold icmp message",
screamer 0:7a64fbb4069d 258 (q->len >= (sizeof(struct icmp_dur_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE)));
screamer 0:7a64fbb4069d 259
screamer 0:7a64fbb4069d 260 iphdr = (struct ip_hdr *)(p->payload); // static_cast<struct ip_hdr *>(x)
screamer 0:7a64fbb4069d 261
screamer 0:7a64fbb4069d 262 idur = (struct icmp_dur_hdr *)(q->payload); // static_cast<struct icmp_dur_hdr *>(x)
screamer 0:7a64fbb4069d 263 ICMPH_TYPE_SET(idur, ICMP_DUR);
screamer 0:7a64fbb4069d 264 ICMPH_CODE_SET(idur, t);
screamer 0:7a64fbb4069d 265
screamer 0:7a64fbb4069d 266 SMEMCPY((u8_t *)q->payload + sizeof(struct icmp_dur_hdr), p->payload,
screamer 0:7a64fbb4069d 267 IP_HLEN + ICMP_DEST_UNREACH_DATASIZE);
screamer 0:7a64fbb4069d 268
screamer 0:7a64fbb4069d 269 /* calculate checksum */
screamer 0:7a64fbb4069d 270 idur->chksum = 0;
screamer 0:7a64fbb4069d 271 idur->chksum = inet_chksum(idur, q->len);
screamer 0:7a64fbb4069d 272 ICMP_STATS_INC(icmp.xmit);
screamer 0:7a64fbb4069d 273 /* increase number of messages attempted to send */
screamer 0:7a64fbb4069d 274 snmp_inc_icmpoutmsgs();
screamer 0:7a64fbb4069d 275 /* increase number of destination unreachable messages attempted to send */
screamer 0:7a64fbb4069d 276 snmp_inc_icmpoutdestunreachs();
screamer 0:7a64fbb4069d 277
screamer 0:7a64fbb4069d 278 struct ip_addr iphdrsrc;
screamer 0:7a64fbb4069d 279 iphdrsrc.addr = iphdr->src.addr;
screamer 0:7a64fbb4069d 280 ip_output(q, NULL, &(iphdrsrc), ICMP_TTL, 0, IP_PROTO_ICMP);
screamer 0:7a64fbb4069d 281 pbuf_free(q);
screamer 0:7a64fbb4069d 282 }
screamer 0:7a64fbb4069d 283
screamer 0:7a64fbb4069d 284 #if IP_FORWARD || IP_REASSEMBLY
screamer 0:7a64fbb4069d 285 /**
screamer 0:7a64fbb4069d 286 * Send a 'time exceeded' packet, called from ip_forward() if TTL is 0.
screamer 0:7a64fbb4069d 287 *
screamer 0:7a64fbb4069d 288 * @param p the input packet for which the 'time exceeded' should be sent,
screamer 0:7a64fbb4069d 289 * p->payload pointing to the IP header
screamer 0:7a64fbb4069d 290 * @param t type of the 'time exceeded' packet
screamer 0:7a64fbb4069d 291 */
screamer 0:7a64fbb4069d 292 void
screamer 0:7a64fbb4069d 293 icmp_time_exceeded(struct pbuf *p, enum icmp_te_type t)
screamer 0:7a64fbb4069d 294 {
screamer 0:7a64fbb4069d 295 struct pbuf *q;
screamer 0:7a64fbb4069d 296 struct ip_hdr *iphdr;
screamer 0:7a64fbb4069d 297 struct icmp_te_hdr *tehdr;
screamer 0:7a64fbb4069d 298
screamer 0:7a64fbb4069d 299 /* ICMP header + IP header + 8 bytes of data */
screamer 0:7a64fbb4069d 300 q = pbuf_alloc(PBUF_IP, sizeof(struct icmp_dur_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE,
screamer 0:7a64fbb4069d 301 PBUF_RAM);
screamer 0:7a64fbb4069d 302 if (q == NULL) {
screamer 0:7a64fbb4069d 303 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded: failed to allocate pbuf for ICMP packet.\n"));
screamer 0:7a64fbb4069d 304 return;
screamer 0:7a64fbb4069d 305 }
screamer 0:7a64fbb4069d 306 LWIP_ASSERT("check that first pbuf can hold icmp message",
screamer 0:7a64fbb4069d 307 (q->len >= (sizeof(struct icmp_dur_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE)));
screamer 0:7a64fbb4069d 308
screamer 0:7a64fbb4069d 309 iphdr = (struct ip_hdr *)(p->payload); // static_cast<struct ip_hdr *>(x)
screamer 0:7a64fbb4069d 310 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded from "));
screamer 0:7a64fbb4069d 311 ip_addr_debug_print(ICMP_DEBUG, &(iphdr->src));
screamer 0:7a64fbb4069d 312 LWIP_DEBUGF(ICMP_DEBUG, (" to "));
screamer 0:7a64fbb4069d 313 ip_addr_debug_print(ICMP_DEBUG, &(iphdr->dest));
screamer 0:7a64fbb4069d 314 LWIP_DEBUGF(ICMP_DEBUG, ("\n"));
screamer 0:7a64fbb4069d 315
screamer 0:7a64fbb4069d 316 tehdr = (struct icmp_te_hdr *)(q->payload); // static_cast<struct icmp_te_hdr *>(x)
screamer 0:7a64fbb4069d 317 ICMPH_TYPE_SET(tehdr, ICMP_TE);
screamer 0:7a64fbb4069d 318 ICMPH_CODE_SET(tehdr, t);
screamer 0:7a64fbb4069d 319
screamer 0:7a64fbb4069d 320 /* copy fields from original packet */
screamer 0:7a64fbb4069d 321 SMEMCPY((u8_t *)q->payload + sizeof(struct icmp_dur_hdr), (u8_t *)p->payload,
screamer 0:7a64fbb4069d 322 IP_HLEN + ICMP_DEST_UNREACH_DATASIZE);
screamer 0:7a64fbb4069d 323
screamer 0:7a64fbb4069d 324 /* calculate checksum */
screamer 0:7a64fbb4069d 325 tehdr->chksum = 0;
screamer 0:7a64fbb4069d 326 tehdr->chksum = inet_chksum(tehdr, q->len);
screamer 0:7a64fbb4069d 327 ICMP_STATS_INC(icmp.xmit);
screamer 0:7a64fbb4069d 328 /* increase number of messages attempted to send */
screamer 0:7a64fbb4069d 329 snmp_inc_icmpoutmsgs();
screamer 0:7a64fbb4069d 330 /* increase number of destination unreachable messages attempted to send */
screamer 0:7a64fbb4069d 331 snmp_inc_icmpouttimeexcds();
screamer 0:7a64fbb4069d 332 struct ip_addr iphdrsrc;
screamer 0:7a64fbb4069d 333 iphdrsrc.addr = iphdr->src.addr;
screamer 0:7a64fbb4069d 334 ip_output(q, NULL, &iphdrsrc, ICMP_TTL, 0, IP_PROTO_ICMP);
screamer 0:7a64fbb4069d 335 pbuf_free(q);
screamer 0:7a64fbb4069d 336 }
screamer 0:7a64fbb4069d 337
screamer 0:7a64fbb4069d 338 #endif /* IP_FORWARD */
screamer 0:7a64fbb4069d 339
screamer 0:7a64fbb4069d 340 #endif /* LWIP_ICMP */