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NetServices/lwip/core/ipv4/icmp.c@0:05ccbd4f84f1, 2013-12-02 (annotated)

Committer:
hendrikvincent
Date:
Mon Dec 02 09:01:23 2013 +0000
Revision:
0:05ccbd4f84f1
eerste programma;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
hendrikvincent 0:05ccbd4f84f1 1 /**
hendrikvincent 0:05ccbd4f84f1 2 * @file
hendrikvincent 0:05ccbd4f84f1 3 * ICMP - Internet Control Message Protocol
hendrikvincent 0:05ccbd4f84f1 4 *
hendrikvincent 0:05ccbd4f84f1 5 */
hendrikvincent 0:05ccbd4f84f1 6
hendrikvincent 0:05ccbd4f84f1 7 /*
hendrikvincent 0:05ccbd4f84f1 8 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
hendrikvincent 0:05ccbd4f84f1 9 * All rights reserved.
hendrikvincent 0:05ccbd4f84f1 10 *
hendrikvincent 0:05ccbd4f84f1 11 * Redistribution and use in source and binary forms, with or without modification,
hendrikvincent 0:05ccbd4f84f1 12 * are permitted provided that the following conditions are met:
hendrikvincent 0:05ccbd4f84f1 13 *
hendrikvincent 0:05ccbd4f84f1 14 * 1. Redistributions of source code must retain the above copyright notice,
hendrikvincent 0:05ccbd4f84f1 15 * this list of conditions and the following disclaimer.
hendrikvincent 0:05ccbd4f84f1 16 * 2. Redistributions in binary form must reproduce the above copyright notice,
hendrikvincent 0:05ccbd4f84f1 17 * this list of conditions and the following disclaimer in the documentation
hendrikvincent 0:05ccbd4f84f1 18 * and/or other materials provided with the distribution.
hendrikvincent 0:05ccbd4f84f1 19 * 3. The name of the author may not be used to endorse or promote products
hendrikvincent 0:05ccbd4f84f1 20 * derived from this software without specific prior written permission.
hendrikvincent 0:05ccbd4f84f1 21 *
hendrikvincent 0:05ccbd4f84f1 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
hendrikvincent 0:05ccbd4f84f1 23 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
hendrikvincent 0:05ccbd4f84f1 24 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
hendrikvincent 0:05ccbd4f84f1 25 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
hendrikvincent 0:05ccbd4f84f1 26 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
hendrikvincent 0:05ccbd4f84f1 27 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
hendrikvincent 0:05ccbd4f84f1 28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
hendrikvincent 0:05ccbd4f84f1 29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
hendrikvincent 0:05ccbd4f84f1 30 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
hendrikvincent 0:05ccbd4f84f1 31 * OF SUCH DAMAGE.
hendrikvincent 0:05ccbd4f84f1 32 *
hendrikvincent 0:05ccbd4f84f1 33 * This file is part of the lwIP TCP/IP stack.
hendrikvincent 0:05ccbd4f84f1 34 *
hendrikvincent 0:05ccbd4f84f1 35 * Author: Adam Dunkels <adam@sics.se>
hendrikvincent 0:05ccbd4f84f1 36 *
hendrikvincent 0:05ccbd4f84f1 37 */
hendrikvincent 0:05ccbd4f84f1 38
hendrikvincent 0:05ccbd4f84f1 39 /* Some ICMP messages should be passed to the transport protocols. This
hendrikvincent 0:05ccbd4f84f1 40 is not implemented. */
hendrikvincent 0:05ccbd4f84f1 41
hendrikvincent 0:05ccbd4f84f1 42 #include "lwip/opt.h"
hendrikvincent 0:05ccbd4f84f1 43
hendrikvincent 0:05ccbd4f84f1 44 #if LWIP_ICMP /* don't build if not configured for use in lwipopts.h */
hendrikvincent 0:05ccbd4f84f1 45
hendrikvincent 0:05ccbd4f84f1 46 #include "lwip/icmp.h"
hendrikvincent 0:05ccbd4f84f1 47 #include "lwip/inet_chksum.h"
hendrikvincent 0:05ccbd4f84f1 48 #include "lwip/ip.h"
hendrikvincent 0:05ccbd4f84f1 49 #include "lwip/def.h"
hendrikvincent 0:05ccbd4f84f1 50 #include "lwip/stats.h"
hendrikvincent 0:05ccbd4f84f1 51 #include "lwip/snmp.h"
hendrikvincent 0:05ccbd4f84f1 52
hendrikvincent 0:05ccbd4f84f1 53 #include <string.h>
hendrikvincent 0:05ccbd4f84f1 54
hendrikvincent 0:05ccbd4f84f1 55 /** Small optimization: set to 0 if incoming PBUF_POOL pbuf always can be
hendrikvincent 0:05ccbd4f84f1 56 * used to modify and send a response packet (and to 1 if this is not the case,
hendrikvincent 0:05ccbd4f84f1 57 * e.g. when link header is stripped of when receiving) */
hendrikvincent 0:05ccbd4f84f1 58 #ifndef LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
hendrikvincent 0:05ccbd4f84f1 59 #define LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN 1
hendrikvincent 0:05ccbd4f84f1 60 #endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
hendrikvincent 0:05ccbd4f84f1 61
hendrikvincent 0:05ccbd4f84f1 62 /* The amount of data from the original packet to return in a dest-unreachable */
hendrikvincent 0:05ccbd4f84f1 63 #define ICMP_DEST_UNREACH_DATASIZE 8
hendrikvincent 0:05ccbd4f84f1 64
hendrikvincent 0:05ccbd4f84f1 65 static void icmp_send_response(struct pbuf *p, u8_t type, u8_t code);
hendrikvincent 0:05ccbd4f84f1 66
hendrikvincent 0:05ccbd4f84f1 67 /**
hendrikvincent 0:05ccbd4f84f1 68 * Processes ICMP input packets, called from ip_input().
hendrikvincent 0:05ccbd4f84f1 69 *
hendrikvincent 0:05ccbd4f84f1 70 * Currently only processes icmp echo requests and sends
hendrikvincent 0:05ccbd4f84f1 71 * out the echo response.
hendrikvincent 0:05ccbd4f84f1 72 *
hendrikvincent 0:05ccbd4f84f1 73 * @param p the icmp echo request packet, p->payload pointing to the ip header
hendrikvincent 0:05ccbd4f84f1 74 * @param inp the netif on which this packet was received
hendrikvincent 0:05ccbd4f84f1 75 */
hendrikvincent 0:05ccbd4f84f1 76 void
hendrikvincent 0:05ccbd4f84f1 77 icmp_input(struct pbuf *p, struct netif *inp)
hendrikvincent 0:05ccbd4f84f1 78 {
hendrikvincent 0:05ccbd4f84f1 79 u8_t type;
hendrikvincent 0:05ccbd4f84f1 80 #ifdef LWIP_DEBUG
hendrikvincent 0:05ccbd4f84f1 81 u8_t code;
hendrikvincent 0:05ccbd4f84f1 82 #endif /* LWIP_DEBUG */
hendrikvincent 0:05ccbd4f84f1 83 struct icmp_echo_hdr *iecho;
hendrikvincent 0:05ccbd4f84f1 84 struct ip_hdr *iphdr;
hendrikvincent 0:05ccbd4f84f1 85 s16_t hlen;
hendrikvincent 0:05ccbd4f84f1 86
hendrikvincent 0:05ccbd4f84f1 87 ICMP_STATS_INC(icmp.recv);
hendrikvincent 0:05ccbd4f84f1 88 snmp_inc_icmpinmsgs();
hendrikvincent 0:05ccbd4f84f1 89
hendrikvincent 0:05ccbd4f84f1 90
hendrikvincent 0:05ccbd4f84f1 91 iphdr = (struct ip_hdr *)p->payload;
hendrikvincent 0:05ccbd4f84f1 92 hlen = IPH_HL(iphdr) * 4;
hendrikvincent 0:05ccbd4f84f1 93 if (pbuf_header(p, -hlen) || (p->tot_len < sizeof(u16_t)*2)) {
hendrikvincent 0:05ccbd4f84f1 94 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: short ICMP (%"U16_F" bytes) received\n", p->tot_len));
hendrikvincent 0:05ccbd4f84f1 95 goto lenerr;
hendrikvincent 0:05ccbd4f84f1 96 }
hendrikvincent 0:05ccbd4f84f1 97
hendrikvincent 0:05ccbd4f84f1 98 type = *((u8_t *)p->payload);
hendrikvincent 0:05ccbd4f84f1 99 #ifdef LWIP_DEBUG
hendrikvincent 0:05ccbd4f84f1 100 code = *(((u8_t *)p->payload)+1);
hendrikvincent 0:05ccbd4f84f1 101 #endif /* LWIP_DEBUG */
hendrikvincent 0:05ccbd4f84f1 102 switch (type) {
hendrikvincent 0:05ccbd4f84f1 103 case ICMP_ER:
hendrikvincent 0:05ccbd4f84f1 104 /* This is OK, echo reply might have been parsed by a raw PCB
hendrikvincent 0:05ccbd4f84f1 105 (as obviously, an echo request has been sent, too). */
hendrikvincent 0:05ccbd4f84f1 106 break;
hendrikvincent 0:05ccbd4f84f1 107 case ICMP_ECHO:
hendrikvincent 0:05ccbd4f84f1 108 #if !LWIP_MULTICAST_PING || !LWIP_BROADCAST_PING
hendrikvincent 0:05ccbd4f84f1 109 {
hendrikvincent 0:05ccbd4f84f1 110 int accepted = 1;
hendrikvincent 0:05ccbd4f84f1 111 #if !LWIP_MULTICAST_PING
hendrikvincent 0:05ccbd4f84f1 112 /* multicast destination address? */
hendrikvincent 0:05ccbd4f84f1 113 if (ip_addr_ismulticast(&current_iphdr_dest)) {
hendrikvincent 0:05ccbd4f84f1 114 accepted = 0;
hendrikvincent 0:05ccbd4f84f1 115 }
hendrikvincent 0:05ccbd4f84f1 116 #endif /* LWIP_MULTICAST_PING */
hendrikvincent 0:05ccbd4f84f1 117 #if !LWIP_BROADCAST_PING
hendrikvincent 0:05ccbd4f84f1 118 /* broadcast destination address? */
hendrikvincent 0:05ccbd4f84f1 119 if (ip_addr_isbroadcast(&current_iphdr_dest, inp)) {
hendrikvincent 0:05ccbd4f84f1 120 accepted = 0;
hendrikvincent 0:05ccbd4f84f1 121 }
hendrikvincent 0:05ccbd4f84f1 122 #endif /* LWIP_BROADCAST_PING */
hendrikvincent 0:05ccbd4f84f1 123 /* broadcast or multicast destination address not acceptd? */
hendrikvincent 0:05ccbd4f84f1 124 if (!accepted) {
hendrikvincent 0:05ccbd4f84f1 125 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to multicast or broadcast pings\n"));
hendrikvincent 0:05ccbd4f84f1 126 ICMP_STATS_INC(icmp.err);
hendrikvincent 0:05ccbd4f84f1 127 pbuf_free(p);
hendrikvincent 0:05ccbd4f84f1 128 return;
hendrikvincent 0:05ccbd4f84f1 129 }
hendrikvincent 0:05ccbd4f84f1 130 }
hendrikvincent 0:05ccbd4f84f1 131 #endif /* !LWIP_MULTICAST_PING || !LWIP_BROADCAST_PING */
hendrikvincent 0:05ccbd4f84f1 132 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ping\n"));
hendrikvincent 0:05ccbd4f84f1 133 if (p->tot_len < sizeof(struct icmp_echo_hdr)) {
hendrikvincent 0:05ccbd4f84f1 134 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: bad ICMP echo received\n"));
hendrikvincent 0:05ccbd4f84f1 135 goto lenerr;
hendrikvincent 0:05ccbd4f84f1 136 }
hendrikvincent 0:05ccbd4f84f1 137 if (inet_chksum_pbuf(p) != 0) {
hendrikvincent 0:05ccbd4f84f1 138 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: checksum failed for received ICMP echo\n"));
hendrikvincent 0:05ccbd4f84f1 139 pbuf_free(p);
hendrikvincent 0:05ccbd4f84f1 140 ICMP_STATS_INC(icmp.chkerr);
hendrikvincent 0:05ccbd4f84f1 141 snmp_inc_icmpinerrors();
hendrikvincent 0:05ccbd4f84f1 142 return;
hendrikvincent 0:05ccbd4f84f1 143 }
hendrikvincent 0:05ccbd4f84f1 144 #if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
hendrikvincent 0:05ccbd4f84f1 145 if (pbuf_header(p, (PBUF_IP_HLEN + PBUF_LINK_HLEN))) {
hendrikvincent 0:05ccbd4f84f1 146 /* p is not big enough to contain link headers
hendrikvincent 0:05ccbd4f84f1 147 * allocate a new one and copy p into it
hendrikvincent 0:05ccbd4f84f1 148 */
hendrikvincent 0:05ccbd4f84f1 149 struct pbuf *r;
hendrikvincent 0:05ccbd4f84f1 150 /* switch p->payload to ip header */
hendrikvincent 0:05ccbd4f84f1 151 if (pbuf_header(p, hlen)) {
hendrikvincent 0:05ccbd4f84f1 152 LWIP_ASSERT("icmp_input: moving p->payload to ip header failed\n", 0);
hendrikvincent 0:05ccbd4f84f1 153 goto memerr;
hendrikvincent 0:05ccbd4f84f1 154 }
hendrikvincent 0:05ccbd4f84f1 155 /* allocate new packet buffer with space for link headers */
hendrikvincent 0:05ccbd4f84f1 156 r = pbuf_alloc(PBUF_LINK, p->tot_len, PBUF_RAM);
hendrikvincent 0:05ccbd4f84f1 157 if (r == NULL) {
hendrikvincent 0:05ccbd4f84f1 158 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: allocating new pbuf failed\n"));
hendrikvincent 0:05ccbd4f84f1 159 goto memerr;
hendrikvincent 0:05ccbd4f84f1 160 }
hendrikvincent 0:05ccbd4f84f1 161 LWIP_ASSERT("check that first pbuf can hold struct the ICMP header",
hendrikvincent 0:05ccbd4f84f1 162 (r->len >= hlen + sizeof(struct icmp_echo_hdr)));
hendrikvincent 0:05ccbd4f84f1 163 /* copy the whole packet including ip header */
hendrikvincent 0:05ccbd4f84f1 164 if (pbuf_copy(r, p) != ERR_OK) {
hendrikvincent 0:05ccbd4f84f1 165 LWIP_ASSERT("icmp_input: copying to new pbuf failed\n", 0);
hendrikvincent 0:05ccbd4f84f1 166 goto memerr;
hendrikvincent 0:05ccbd4f84f1 167 }
hendrikvincent 0:05ccbd4f84f1 168 iphdr = (struct ip_hdr *)r->payload;
hendrikvincent 0:05ccbd4f84f1 169 /* switch r->payload back to icmp header */
hendrikvincent 0:05ccbd4f84f1 170 if (pbuf_header(r, -hlen)) {
hendrikvincent 0:05ccbd4f84f1 171 LWIP_ASSERT("icmp_input: restoring original p->payload failed\n", 0);
hendrikvincent 0:05ccbd4f84f1 172 goto memerr;
hendrikvincent 0:05ccbd4f84f1 173 }
hendrikvincent 0:05ccbd4f84f1 174 /* free the original p */
hendrikvincent 0:05ccbd4f84f1 175 pbuf_free(p);
hendrikvincent 0:05ccbd4f84f1 176 /* we now have an identical copy of p that has room for link headers */
hendrikvincent 0:05ccbd4f84f1 177 p = r;
hendrikvincent 0:05ccbd4f84f1 178 } else {
hendrikvincent 0:05ccbd4f84f1 179 /* restore p->payload to point to icmp header */
hendrikvincent 0:05ccbd4f84f1 180 if (pbuf_header(p, -(s16_t)(PBUF_IP_HLEN + PBUF_LINK_HLEN))) {
hendrikvincent 0:05ccbd4f84f1 181 LWIP_ASSERT("icmp_input: restoring original p->payload failed\n", 0);
hendrikvincent 0:05ccbd4f84f1 182 goto memerr;
hendrikvincent 0:05ccbd4f84f1 183 }
hendrikvincent 0:05ccbd4f84f1 184 }
hendrikvincent 0:05ccbd4f84f1 185 #endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
hendrikvincent 0:05ccbd4f84f1 186 /* At this point, all checks are OK. */
hendrikvincent 0:05ccbd4f84f1 187 /* We generate an answer by switching the dest and src ip addresses,
hendrikvincent 0:05ccbd4f84f1 188 * setting the icmp type to ECHO_RESPONSE and updating the checksum. */
hendrikvincent 0:05ccbd4f84f1 189 iecho = (struct icmp_echo_hdr *)p->payload;
hendrikvincent 0:05ccbd4f84f1 190 ip_addr_copy(iphdr->src, *ip_current_dest_addr());
hendrikvincent 0:05ccbd4f84f1 191 ip_addr_copy(iphdr->dest, *ip_current_src_addr());
hendrikvincent 0:05ccbd4f84f1 192 ICMPH_TYPE_SET(iecho, ICMP_ER);
hendrikvincent 0:05ccbd4f84f1 193 /* adjust the checksum */
hendrikvincent 0:05ccbd4f84f1 194 if (iecho->chksum >= PP_HTONS(0xffff - (ICMP_ECHO << 8))) {
hendrikvincent 0:05ccbd4f84f1 195 iecho->chksum += PP_HTONS(ICMP_ECHO << 8) + 1;
hendrikvincent 0:05ccbd4f84f1 196 } else {
hendrikvincent 0:05ccbd4f84f1 197 iecho->chksum += PP_HTONS(ICMP_ECHO << 8);
hendrikvincent 0:05ccbd4f84f1 198 }
hendrikvincent 0:05ccbd4f84f1 199
hendrikvincent 0:05ccbd4f84f1 200 /* Set the correct TTL and recalculate the header checksum. */
hendrikvincent 0:05ccbd4f84f1 201 IPH_TTL_SET(iphdr, ICMP_TTL);
hendrikvincent 0:05ccbd4f84f1 202 IPH_CHKSUM_SET(iphdr, 0);
hendrikvincent 0:05ccbd4f84f1 203 #if CHECKSUM_GEN_IP
hendrikvincent 0:05ccbd4f84f1 204 IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
hendrikvincent 0:05ccbd4f84f1 205 #endif /* CHECKSUM_GEN_IP */
hendrikvincent 0:05ccbd4f84f1 206
hendrikvincent 0:05ccbd4f84f1 207 ICMP_STATS_INC(icmp.xmit);
hendrikvincent 0:05ccbd4f84f1 208 /* increase number of messages attempted to send */
hendrikvincent 0:05ccbd4f84f1 209 snmp_inc_icmpoutmsgs();
hendrikvincent 0:05ccbd4f84f1 210 /* increase number of echo replies attempted to send */
hendrikvincent 0:05ccbd4f84f1 211 snmp_inc_icmpoutechoreps();
hendrikvincent 0:05ccbd4f84f1 212
hendrikvincent 0:05ccbd4f84f1 213 if(pbuf_header(p, hlen)) {
hendrikvincent 0:05ccbd4f84f1 214 LWIP_ASSERT("Can't move over header in packet", 0);
hendrikvincent 0:05ccbd4f84f1 215 } else {
hendrikvincent 0:05ccbd4f84f1 216 err_t ret;
hendrikvincent 0:05ccbd4f84f1 217 /* send an ICMP packet, src addr is the dest addr of the curren packet */
hendrikvincent 0:05ccbd4f84f1 218 ret = ip_output_if(p, ip_current_dest_addr(), IP_HDRINCL,
hendrikvincent 0:05ccbd4f84f1 219 ICMP_TTL, 0, IP_PROTO_ICMP, inp);
hendrikvincent 0:05ccbd4f84f1 220 if (ret != ERR_OK) {
hendrikvincent 0:05ccbd4f84f1 221 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ip_output_if returned an error: %c.\n", ret));
hendrikvincent 0:05ccbd4f84f1 222 }
hendrikvincent 0:05ccbd4f84f1 223 }
hendrikvincent 0:05ccbd4f84f1 224 break;
hendrikvincent 0:05ccbd4f84f1 225 default:
hendrikvincent 0:05ccbd4f84f1 226 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ICMP type %"S16_F" code %"S16_F" not supported.\n",
hendrikvincent 0:05ccbd4f84f1 227 (s16_t)type, (s16_t)code));
hendrikvincent 0:05ccbd4f84f1 228 ICMP_STATS_INC(icmp.proterr);
hendrikvincent 0:05ccbd4f84f1 229 ICMP_STATS_INC(icmp.drop);
hendrikvincent 0:05ccbd4f84f1 230 }
hendrikvincent 0:05ccbd4f84f1 231 pbuf_free(p);
hendrikvincent 0:05ccbd4f84f1 232 return;
hendrikvincent 0:05ccbd4f84f1 233 lenerr:
hendrikvincent 0:05ccbd4f84f1 234 pbuf_free(p);
hendrikvincent 0:05ccbd4f84f1 235 ICMP_STATS_INC(icmp.lenerr);
hendrikvincent 0:05ccbd4f84f1 236 snmp_inc_icmpinerrors();
hendrikvincent 0:05ccbd4f84f1 237 return;
hendrikvincent 0:05ccbd4f84f1 238 #if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
hendrikvincent 0:05ccbd4f84f1 239 memerr:
hendrikvincent 0:05ccbd4f84f1 240 pbuf_free(p);
hendrikvincent 0:05ccbd4f84f1 241 ICMP_STATS_INC(icmp.err);
hendrikvincent 0:05ccbd4f84f1 242 snmp_inc_icmpinerrors();
hendrikvincent 0:05ccbd4f84f1 243 return;
hendrikvincent 0:05ccbd4f84f1 244 #endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
hendrikvincent 0:05ccbd4f84f1 245 }
hendrikvincent 0:05ccbd4f84f1 246
hendrikvincent 0:05ccbd4f84f1 247 /**
hendrikvincent 0:05ccbd4f84f1 248 * Send an icmp 'destination unreachable' packet, called from ip_input() if
hendrikvincent 0:05ccbd4f84f1 249 * the transport layer protocol is unknown and from udp_input() if the local
hendrikvincent 0:05ccbd4f84f1 250 * port is not bound.
hendrikvincent 0:05ccbd4f84f1 251 *
hendrikvincent 0:05ccbd4f84f1 252 * @param p the input packet for which the 'unreachable' should be sent,
hendrikvincent 0:05ccbd4f84f1 253 * p->payload pointing to the IP header
hendrikvincent 0:05ccbd4f84f1 254 * @param t type of the 'unreachable' packet
hendrikvincent 0:05ccbd4f84f1 255 */
hendrikvincent 0:05ccbd4f84f1 256 void
hendrikvincent 0:05ccbd4f84f1 257 icmp_dest_unreach(struct pbuf *p, enum icmp_dur_type t)
hendrikvincent 0:05ccbd4f84f1 258 {
hendrikvincent 0:05ccbd4f84f1 259 icmp_send_response(p, ICMP_DUR, t);
hendrikvincent 0:05ccbd4f84f1 260 }
hendrikvincent 0:05ccbd4f84f1 261
hendrikvincent 0:05ccbd4f84f1 262 #if IP_FORWARD || IP_REASSEMBLY
hendrikvincent 0:05ccbd4f84f1 263 /**
hendrikvincent 0:05ccbd4f84f1 264 * Send a 'time exceeded' packet, called from ip_forward() if TTL is 0.
hendrikvincent 0:05ccbd4f84f1 265 *
hendrikvincent 0:05ccbd4f84f1 266 * @param p the input packet for which the 'time exceeded' should be sent,
hendrikvincent 0:05ccbd4f84f1 267 * p->payload pointing to the IP header
hendrikvincent 0:05ccbd4f84f1 268 * @param t type of the 'time exceeded' packet
hendrikvincent 0:05ccbd4f84f1 269 */
hendrikvincent 0:05ccbd4f84f1 270 void
hendrikvincent 0:05ccbd4f84f1 271 icmp_time_exceeded(struct pbuf *p, enum icmp_te_type t)
hendrikvincent 0:05ccbd4f84f1 272 {
hendrikvincent 0:05ccbd4f84f1 273 icmp_send_response(p, ICMP_TE, t);
hendrikvincent 0:05ccbd4f84f1 274 }
hendrikvincent 0:05ccbd4f84f1 275
hendrikvincent 0:05ccbd4f84f1 276 #endif /* IP_FORWARD || IP_REASSEMBLY */
hendrikvincent 0:05ccbd4f84f1 277
hendrikvincent 0:05ccbd4f84f1 278 /**
hendrikvincent 0:05ccbd4f84f1 279 * Send an icmp packet in response to an incoming packet.
hendrikvincent 0:05ccbd4f84f1 280 *
hendrikvincent 0:05ccbd4f84f1 281 * @param p the input packet for which the 'unreachable' should be sent,
hendrikvincent 0:05ccbd4f84f1 282 * p->payload pointing to the IP header
hendrikvincent 0:05ccbd4f84f1 283 * @param type Type of the ICMP header
hendrikvincent 0:05ccbd4f84f1 284 * @param code Code of the ICMP header
hendrikvincent 0:05ccbd4f84f1 285 */
hendrikvincent 0:05ccbd4f84f1 286 static void
hendrikvincent 0:05ccbd4f84f1 287 icmp_send_response(struct pbuf *p, u8_t type, u8_t code)
hendrikvincent 0:05ccbd4f84f1 288 {
hendrikvincent 0:05ccbd4f84f1 289 struct pbuf *q;
hendrikvincent 0:05ccbd4f84f1 290 struct ip_hdr *iphdr;
hendrikvincent 0:05ccbd4f84f1 291 /* we can use the echo header here */
hendrikvincent 0:05ccbd4f84f1 292 struct icmp_echo_hdr *icmphdr;
hendrikvincent 0:05ccbd4f84f1 293 ip_addr_t iphdr_src;
hendrikvincent 0:05ccbd4f84f1 294
hendrikvincent 0:05ccbd4f84f1 295 /* ICMP header + IP header + 8 bytes of data */
hendrikvincent 0:05ccbd4f84f1 296 q = pbuf_alloc(PBUF_IP, sizeof(struct icmp_echo_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE,
hendrikvincent 0:05ccbd4f84f1 297 PBUF_RAM);
hendrikvincent 0:05ccbd4f84f1 298 if (q == NULL) {
hendrikvincent 0:05ccbd4f84f1 299 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded: failed to allocate pbuf for ICMP packet.\n"));
hendrikvincent 0:05ccbd4f84f1 300 return;
hendrikvincent 0:05ccbd4f84f1 301 }
hendrikvincent 0:05ccbd4f84f1 302 LWIP_ASSERT("check that first pbuf can hold icmp message",
hendrikvincent 0:05ccbd4f84f1 303 (q->len >= (sizeof(struct icmp_echo_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE)));
hendrikvincent 0:05ccbd4f84f1 304
hendrikvincent 0:05ccbd4f84f1 305 iphdr = (struct ip_hdr *)p->payload;
hendrikvincent 0:05ccbd4f84f1 306 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded from "));
hendrikvincent 0:05ccbd4f84f1 307 ip_addr_debug_print(ICMP_DEBUG, &(iphdr->src));
hendrikvincent 0:05ccbd4f84f1 308 LWIP_DEBUGF(ICMP_DEBUG, (" to "));
hendrikvincent 0:05ccbd4f84f1 309 ip_addr_debug_print(ICMP_DEBUG, &(iphdr->dest));
hendrikvincent 0:05ccbd4f84f1 310 LWIP_DEBUGF(ICMP_DEBUG, ("\n"));
hendrikvincent 0:05ccbd4f84f1 311
hendrikvincent 0:05ccbd4f84f1 312 icmphdr = (struct icmp_echo_hdr *)q->payload;
hendrikvincent 0:05ccbd4f84f1 313 icmphdr->type = type;
hendrikvincent 0:05ccbd4f84f1 314 icmphdr->code = code;
hendrikvincent 0:05ccbd4f84f1 315 icmphdr->id = 0;
hendrikvincent 0:05ccbd4f84f1 316 icmphdr->seqno = 0;
hendrikvincent 0:05ccbd4f84f1 317
hendrikvincent 0:05ccbd4f84f1 318 /* copy fields from original packet */
hendrikvincent 0:05ccbd4f84f1 319 SMEMCPY((u8_t *)q->payload + sizeof(struct icmp_echo_hdr), (u8_t *)p->payload,
hendrikvincent 0:05ccbd4f84f1 320 IP_HLEN + ICMP_DEST_UNREACH_DATASIZE);
hendrikvincent 0:05ccbd4f84f1 321
hendrikvincent 0:05ccbd4f84f1 322 /* calculate checksum */
hendrikvincent 0:05ccbd4f84f1 323 icmphdr->chksum = 0;
hendrikvincent 0:05ccbd4f84f1 324 icmphdr->chksum = inet_chksum(icmphdr, q->len);
hendrikvincent 0:05ccbd4f84f1 325 ICMP_STATS_INC(icmp.xmit);
hendrikvincent 0:05ccbd4f84f1 326 /* increase number of messages attempted to send */
hendrikvincent 0:05ccbd4f84f1 327 snmp_inc_icmpoutmsgs();
hendrikvincent 0:05ccbd4f84f1 328 /* increase number of destination unreachable messages attempted to send */
hendrikvincent 0:05ccbd4f84f1 329 snmp_inc_icmpouttimeexcds();
hendrikvincent 0:05ccbd4f84f1 330 ip_addr_copy(iphdr_src, iphdr->src);
hendrikvincent 0:05ccbd4f84f1 331 ip_output(q, NULL, &iphdr_src, ICMP_TTL, 0, IP_PROTO_ICMP);
hendrikvincent 0:05ccbd4f84f1 332 pbuf_free(q);
hendrikvincent 0:05ccbd4f84f1 333 }
hendrikvincent 0:05ccbd4f84f1 334
hendrikvincent 0:05ccbd4f84f1 335 #endif /* LWIP_ICMP */