Donatien Garnier
NetServices Stack source
Dependents: HelloWorld ServoInterfaceBoardExample1 4180_Lab4
lwip/core/ipv4/icmp.c@5:dd63a1e02b1b, 2010-07-27 (annotated)
- Committer:
- donatien
- Date:
- Tue Jul 27 15:59:42 2010 +0000
- Revision:
- 5:dd63a1e02b1b
- Parent:
- 0:632c9925f013
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| donatien | 0:632c9925f013 | 1 | /** |
| donatien | 0:632c9925f013 | 2 | * @file |
| donatien | 0:632c9925f013 | 3 | * ICMP - Internet Control Message Protocol |
| donatien | 0:632c9925f013 | 4 | * |
| donatien | 0:632c9925f013 | 5 | */ |
| donatien | 0:632c9925f013 | 6 | |
| donatien | 0:632c9925f013 | 7 | /* |
| donatien | 0:632c9925f013 | 8 | * Copyright (c) 2001-2004 Swedish Institute of Computer Science. |
| donatien | 0:632c9925f013 | 9 | * All rights reserved. |
| donatien | 0:632c9925f013 | 10 | * |
| donatien | 0:632c9925f013 | 11 | * Redistribution and use in source and binary forms, with or without modification, |
| donatien | 0:632c9925f013 | 12 | * are permitted provided that the following conditions are met: |
| donatien | 0:632c9925f013 | 13 | * |
| donatien | 0:632c9925f013 | 14 | * 1. Redistributions of source code must retain the above copyright notice, |
| donatien | 0:632c9925f013 | 15 | * this list of conditions and the following disclaimer. |
| donatien | 0:632c9925f013 | 16 | * 2. Redistributions in binary form must reproduce the above copyright notice, |
| donatien | 0:632c9925f013 | 17 | * this list of conditions and the following disclaimer in the documentation |
| donatien | 0:632c9925f013 | 18 | * and/or other materials provided with the distribution. |
| donatien | 0:632c9925f013 | 19 | * 3. The name of the author may not be used to endorse or promote products |
| donatien | 0:632c9925f013 | 20 | * derived from this software without specific prior written permission. |
| donatien | 0:632c9925f013 | 21 | * |
| donatien | 0:632c9925f013 | 22 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED |
| donatien | 0:632c9925f013 | 23 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF |
| donatien | 0:632c9925f013 | 24 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT |
| donatien | 0:632c9925f013 | 25 | * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| donatien | 0:632c9925f013 | 26 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT |
| donatien | 0:632c9925f013 | 27 | * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| donatien | 0:632c9925f013 | 28 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| donatien | 0:632c9925f013 | 29 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING |
| donatien | 0:632c9925f013 | 30 | * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY |
| donatien | 0:632c9925f013 | 31 | * OF SUCH DAMAGE. |
| donatien | 0:632c9925f013 | 32 | * |
| donatien | 0:632c9925f013 | 33 | * This file is part of the lwIP TCP/IP stack. |
| donatien | 0:632c9925f013 | 34 | * |
| donatien | 0:632c9925f013 | 35 | * Author: Adam Dunkels <adam@sics.se> |
| donatien | 0:632c9925f013 | 36 | * |
| donatien | 0:632c9925f013 | 37 | */ |
| donatien | 0:632c9925f013 | 38 | |
| donatien | 0:632c9925f013 | 39 | /* Some ICMP messages should be passed to the transport protocols. This |
| donatien | 0:632c9925f013 | 40 | is not implemented. */ |
| donatien | 0:632c9925f013 | 41 | |
| donatien | 0:632c9925f013 | 42 | #include "lwip/opt.h" |
| donatien | 0:632c9925f013 | 43 | |
| donatien | 0:632c9925f013 | 44 | #if LWIP_ICMP /* don't build if not configured for use in lwipopts.h */ |
| donatien | 0:632c9925f013 | 45 | |
| donatien | 0:632c9925f013 | 46 | #include "lwip/icmp.h" |
| donatien | 0:632c9925f013 | 47 | #include "lwip/inet_chksum.h" |
| donatien | 0:632c9925f013 | 48 | #include "lwip/ip.h" |
| donatien | 0:632c9925f013 | 49 | #include "lwip/def.h" |
| donatien | 0:632c9925f013 | 50 | #include "lwip/stats.h" |
| donatien | 0:632c9925f013 | 51 | #include "lwip/snmp.h" |
| donatien | 0:632c9925f013 | 52 | |
| donatien | 0:632c9925f013 | 53 | #include <string.h> |
| donatien | 0:632c9925f013 | 54 | |
| donatien | 0:632c9925f013 | 55 | /** Small optimization: set to 0 if incoming PBUF_POOL pbuf always can be |
| donatien | 0:632c9925f013 | 56 | * used to modify and send a response packet (and to 1 if this is not the case, |
| donatien | 0:632c9925f013 | 57 | * e.g. when link header is stripped of when receiving) */ |
| donatien | 0:632c9925f013 | 58 | #ifndef LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN |
| donatien | 0:632c9925f013 | 59 | #define LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN 1 |
| donatien | 0:632c9925f013 | 60 | #endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */ |
| donatien | 0:632c9925f013 | 61 | |
| donatien | 0:632c9925f013 | 62 | /* The amount of data from the original packet to return in a dest-unreachable */ |
| donatien | 0:632c9925f013 | 63 | #define ICMP_DEST_UNREACH_DATASIZE 8 |
| donatien | 0:632c9925f013 | 64 | |
| donatien | 0:632c9925f013 | 65 | static void icmp_send_response(struct pbuf *p, u8_t type, u8_t code); |
| donatien | 0:632c9925f013 | 66 | |
| donatien | 0:632c9925f013 | 67 | /** |
| donatien | 0:632c9925f013 | 68 | * Processes ICMP input packets, called from ip_input(). |
| donatien | 0:632c9925f013 | 69 | * |
| donatien | 0:632c9925f013 | 70 | * Currently only processes icmp echo requests and sends |
| donatien | 0:632c9925f013 | 71 | * out the echo response. |
| donatien | 0:632c9925f013 | 72 | * |
| donatien | 0:632c9925f013 | 73 | * @param p the icmp echo request packet, p->payload pointing to the ip header |
| donatien | 0:632c9925f013 | 74 | * @param inp the netif on which this packet was received |
| donatien | 0:632c9925f013 | 75 | */ |
| donatien | 0:632c9925f013 | 76 | void |
| donatien | 0:632c9925f013 | 77 | icmp_input(struct pbuf *p, struct netif *inp) |
| donatien | 0:632c9925f013 | 78 | { |
| donatien | 0:632c9925f013 | 79 | u8_t type; |
| donatien | 0:632c9925f013 | 80 | #ifdef LWIP_DEBUG |
| donatien | 0:632c9925f013 | 81 | u8_t code; |
| donatien | 0:632c9925f013 | 82 | #endif /* LWIP_DEBUG */ |
| donatien | 0:632c9925f013 | 83 | struct icmp_echo_hdr *iecho; |
| donatien | 0:632c9925f013 | 84 | struct ip_hdr *iphdr; |
| donatien | 0:632c9925f013 | 85 | s16_t hlen; |
| donatien | 0:632c9925f013 | 86 | |
| donatien | 0:632c9925f013 | 87 | ICMP_STATS_INC(icmp.recv); |
| donatien | 0:632c9925f013 | 88 | snmp_inc_icmpinmsgs(); |
| donatien | 0:632c9925f013 | 89 | |
| donatien | 0:632c9925f013 | 90 | |
| donatien | 0:632c9925f013 | 91 | iphdr = (struct ip_hdr *)p->payload; |
| donatien | 0:632c9925f013 | 92 | hlen = IPH_HL(iphdr) * 4; |
| donatien | 0:632c9925f013 | 93 | if (pbuf_header(p, -hlen) || (p->tot_len < sizeof(u16_t)*2)) { |
| donatien | 0:632c9925f013 | 94 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: short ICMP (%"U16_F" bytes) received\n", p->tot_len)); |
| donatien | 0:632c9925f013 | 95 | goto lenerr; |
| donatien | 0:632c9925f013 | 96 | } |
| donatien | 0:632c9925f013 | 97 | |
| donatien | 0:632c9925f013 | 98 | type = *((u8_t *)p->payload); |
| donatien | 0:632c9925f013 | 99 | #ifdef LWIP_DEBUG |
| donatien | 0:632c9925f013 | 100 | code = *(((u8_t *)p->payload)+1); |
| donatien | 0:632c9925f013 | 101 | #endif /* LWIP_DEBUG */ |
| donatien | 0:632c9925f013 | 102 | switch (type) { |
| donatien | 0:632c9925f013 | 103 | case ICMP_ER: |
| donatien | 0:632c9925f013 | 104 | /* This is OK, echo reply might have been parsed by a raw PCB |
| donatien | 0:632c9925f013 | 105 | (as obviously, an echo request has been sent, too). */ |
| donatien | 0:632c9925f013 | 106 | break; |
| donatien | 0:632c9925f013 | 107 | case ICMP_ECHO: |
| donatien | 0:632c9925f013 | 108 | #if !LWIP_MULTICAST_PING || !LWIP_BROADCAST_PING |
| donatien | 0:632c9925f013 | 109 | { |
| donatien | 0:632c9925f013 | 110 | int accepted = 1; |
| donatien | 0:632c9925f013 | 111 | #if !LWIP_MULTICAST_PING |
| donatien | 0:632c9925f013 | 112 | /* multicast destination address? */ |
| donatien | 5:dd63a1e02b1b | 113 | if (ip_addr_ismulticast(¤t_iphdr_dest)) { |
| donatien | 0:632c9925f013 | 114 | accepted = 0; |
| donatien | 0:632c9925f013 | 115 | } |
| donatien | 0:632c9925f013 | 116 | #endif /* LWIP_MULTICAST_PING */ |
| donatien | 0:632c9925f013 | 117 | #if !LWIP_BROADCAST_PING |
| donatien | 0:632c9925f013 | 118 | /* broadcast destination address? */ |
| donatien | 5:dd63a1e02b1b | 119 | if (ip_addr_isbroadcast(¤t_iphdr_dest, inp)) { |
| donatien | 0:632c9925f013 | 120 | accepted = 0; |
| donatien | 0:632c9925f013 | 121 | } |
| donatien | 0:632c9925f013 | 122 | #endif /* LWIP_BROADCAST_PING */ |
| donatien | 0:632c9925f013 | 123 | /* broadcast or multicast destination address not acceptd? */ |
| donatien | 0:632c9925f013 | 124 | if (!accepted) { |
| donatien | 0:632c9925f013 | 125 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to multicast or broadcast pings\n")); |
| donatien | 0:632c9925f013 | 126 | ICMP_STATS_INC(icmp.err); |
| donatien | 0:632c9925f013 | 127 | pbuf_free(p); |
| donatien | 0:632c9925f013 | 128 | return; |
| donatien | 0:632c9925f013 | 129 | } |
| donatien | 0:632c9925f013 | 130 | } |
| donatien | 0:632c9925f013 | 131 | #endif /* !LWIP_MULTICAST_PING || !LWIP_BROADCAST_PING */ |
| donatien | 0:632c9925f013 | 132 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ping\n")); |
| donatien | 0:632c9925f013 | 133 | if (p->tot_len < sizeof(struct icmp_echo_hdr)) { |
| donatien | 0:632c9925f013 | 134 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: bad ICMP echo received\n")); |
| donatien | 0:632c9925f013 | 135 | goto lenerr; |
| donatien | 0:632c9925f013 | 136 | } |
| donatien | 0:632c9925f013 | 137 | if (inet_chksum_pbuf(p) != 0) { |
| donatien | 0:632c9925f013 | 138 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: checksum failed for received ICMP echo\n")); |
| donatien | 0:632c9925f013 | 139 | pbuf_free(p); |
| donatien | 0:632c9925f013 | 140 | ICMP_STATS_INC(icmp.chkerr); |
| donatien | 0:632c9925f013 | 141 | snmp_inc_icmpinerrors(); |
| donatien | 0:632c9925f013 | 142 | return; |
| donatien | 0:632c9925f013 | 143 | } |
| donatien | 0:632c9925f013 | 144 | #if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN |
| donatien | 0:632c9925f013 | 145 | if (pbuf_header(p, (PBUF_IP_HLEN + PBUF_LINK_HLEN))) { |
| donatien | 0:632c9925f013 | 146 | /* p is not big enough to contain link headers |
| donatien | 0:632c9925f013 | 147 | * allocate a new one and copy p into it |
| donatien | 0:632c9925f013 | 148 | */ |
| donatien | 0:632c9925f013 | 149 | struct pbuf *r; |
| donatien | 0:632c9925f013 | 150 | /* switch p->payload to ip header */ |
| donatien | 0:632c9925f013 | 151 | if (pbuf_header(p, hlen)) { |
| donatien | 0:632c9925f013 | 152 | LWIP_ASSERT("icmp_input: moving p->payload to ip header failed\n", 0); |
| donatien | 0:632c9925f013 | 153 | goto memerr; |
| donatien | 0:632c9925f013 | 154 | } |
| donatien | 0:632c9925f013 | 155 | /* allocate new packet buffer with space for link headers */ |
| donatien | 0:632c9925f013 | 156 | r = pbuf_alloc(PBUF_LINK, p->tot_len, PBUF_RAM); |
| donatien | 0:632c9925f013 | 157 | if (r == NULL) { |
| donatien | 0:632c9925f013 | 158 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: allocating new pbuf failed\n")); |
| donatien | 0:632c9925f013 | 159 | goto memerr; |
| donatien | 0:632c9925f013 | 160 | } |
| donatien | 0:632c9925f013 | 161 | LWIP_ASSERT("check that first pbuf can hold struct the ICMP header", |
| donatien | 0:632c9925f013 | 162 | (r->len >= hlen + sizeof(struct icmp_echo_hdr))); |
| donatien | 0:632c9925f013 | 163 | /* copy the whole packet including ip header */ |
| donatien | 0:632c9925f013 | 164 | if (pbuf_copy(r, p) != ERR_OK) { |
| donatien | 0:632c9925f013 | 165 | LWIP_ASSERT("icmp_input: copying to new pbuf failed\n", 0); |
| donatien | 0:632c9925f013 | 166 | goto memerr; |
| donatien | 0:632c9925f013 | 167 | } |
| donatien | 0:632c9925f013 | 168 | iphdr = (struct ip_hdr *)r->payload; |
| donatien | 0:632c9925f013 | 169 | /* switch r->payload back to icmp header */ |
| donatien | 0:632c9925f013 | 170 | if (pbuf_header(r, -hlen)) { |
| donatien | 0:632c9925f013 | 171 | LWIP_ASSERT("icmp_input: restoring original p->payload failed\n", 0); |
| donatien | 0:632c9925f013 | 172 | goto memerr; |
| donatien | 0:632c9925f013 | 173 | } |
| donatien | 0:632c9925f013 | 174 | /* free the original p */ |
| donatien | 0:632c9925f013 | 175 | pbuf_free(p); |
| donatien | 0:632c9925f013 | 176 | /* we now have an identical copy of p that has room for link headers */ |
| donatien | 0:632c9925f013 | 177 | p = r; |
| donatien | 0:632c9925f013 | 178 | } else { |
| donatien | 0:632c9925f013 | 179 | /* restore p->payload to point to icmp header */ |
| donatien | 0:632c9925f013 | 180 | if (pbuf_header(p, -(s16_t)(PBUF_IP_HLEN + PBUF_LINK_HLEN))) { |
| donatien | 0:632c9925f013 | 181 | LWIP_ASSERT("icmp_input: restoring original p->payload failed\n", 0); |
| donatien | 0:632c9925f013 | 182 | goto memerr; |
| donatien | 0:632c9925f013 | 183 | } |
| donatien | 0:632c9925f013 | 184 | } |
| donatien | 0:632c9925f013 | 185 | #endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */ |
| donatien | 0:632c9925f013 | 186 | /* At this point, all checks are OK. */ |
| donatien | 0:632c9925f013 | 187 | /* We generate an answer by switching the dest and src ip addresses, |
| donatien | 0:632c9925f013 | 188 | * setting the icmp type to ECHO_RESPONSE and updating the checksum. */ |
| donatien | 0:632c9925f013 | 189 | iecho = (struct icmp_echo_hdr *)p->payload; |
| donatien | 5:dd63a1e02b1b | 190 | ip_addr_copy(iphdr->src, *ip_current_dest_addr()); |
| donatien | 5:dd63a1e02b1b | 191 | ip_addr_copy(iphdr->dest, *ip_current_src_addr()); |
| donatien | 0:632c9925f013 | 192 | ICMPH_TYPE_SET(iecho, ICMP_ER); |
| donatien | 0:632c9925f013 | 193 | /* adjust the checksum */ |
| donatien | 5:dd63a1e02b1b | 194 | if (iecho->chksum >= PP_HTONS(0xffff - (ICMP_ECHO << 8))) { |
| donatien | 5:dd63a1e02b1b | 195 | iecho->chksum += PP_HTONS(ICMP_ECHO << 8) + 1; |
| donatien | 0:632c9925f013 | 196 | } else { |
| donatien | 5:dd63a1e02b1b | 197 | iecho->chksum += PP_HTONS(ICMP_ECHO << 8); |
| donatien | 0:632c9925f013 | 198 | } |
| donatien | 0:632c9925f013 | 199 | |
| donatien | 0:632c9925f013 | 200 | /* Set the correct TTL and recalculate the header checksum. */ |
| donatien | 0:632c9925f013 | 201 | IPH_TTL_SET(iphdr, ICMP_TTL); |
| donatien | 0:632c9925f013 | 202 | IPH_CHKSUM_SET(iphdr, 0); |
| donatien | 0:632c9925f013 | 203 | #if CHECKSUM_GEN_IP |
| donatien | 0:632c9925f013 | 204 | IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN)); |
| donatien | 0:632c9925f013 | 205 | #endif /* CHECKSUM_GEN_IP */ |
| donatien | 0:632c9925f013 | 206 | |
| donatien | 0:632c9925f013 | 207 | ICMP_STATS_INC(icmp.xmit); |
| donatien | 0:632c9925f013 | 208 | /* increase number of messages attempted to send */ |
| donatien | 0:632c9925f013 | 209 | snmp_inc_icmpoutmsgs(); |
| donatien | 0:632c9925f013 | 210 | /* increase number of echo replies attempted to send */ |
| donatien | 0:632c9925f013 | 211 | snmp_inc_icmpoutechoreps(); |
| donatien | 0:632c9925f013 | 212 | |
| donatien | 0:632c9925f013 | 213 | if(pbuf_header(p, hlen)) { |
| donatien | 0:632c9925f013 | 214 | LWIP_ASSERT("Can't move over header in packet", 0); |
| donatien | 0:632c9925f013 | 215 | } else { |
| donatien | 0:632c9925f013 | 216 | err_t ret; |
| donatien | 5:dd63a1e02b1b | 217 | /* send an ICMP packet, src addr is the dest addr of the curren packet */ |
| donatien | 5:dd63a1e02b1b | 218 | ret = ip_output_if(p, ip_current_dest_addr(), IP_HDRINCL, |
| donatien | 0:632c9925f013 | 219 | ICMP_TTL, 0, IP_PROTO_ICMP, inp); |
| donatien | 0:632c9925f013 | 220 | if (ret != ERR_OK) { |
| donatien | 0:632c9925f013 | 221 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ip_output_if returned an error: %c.\n", ret)); |
| donatien | 0:632c9925f013 | 222 | } |
| donatien | 0:632c9925f013 | 223 | } |
| donatien | 0:632c9925f013 | 224 | break; |
| donatien | 0:632c9925f013 | 225 | default: |
| donatien | 0:632c9925f013 | 226 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ICMP type %"S16_F" code %"S16_F" not supported.\n", |
| donatien | 0:632c9925f013 | 227 | (s16_t)type, (s16_t)code)); |
| donatien | 0:632c9925f013 | 228 | ICMP_STATS_INC(icmp.proterr); |
| donatien | 0:632c9925f013 | 229 | ICMP_STATS_INC(icmp.drop); |
| donatien | 0:632c9925f013 | 230 | } |
| donatien | 0:632c9925f013 | 231 | pbuf_free(p); |
| donatien | 0:632c9925f013 | 232 | return; |
| donatien | 0:632c9925f013 | 233 | lenerr: |
| donatien | 0:632c9925f013 | 234 | pbuf_free(p); |
| donatien | 0:632c9925f013 | 235 | ICMP_STATS_INC(icmp.lenerr); |
| donatien | 0:632c9925f013 | 236 | snmp_inc_icmpinerrors(); |
| donatien | 0:632c9925f013 | 237 | return; |
| donatien | 0:632c9925f013 | 238 | #if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN |
| donatien | 0:632c9925f013 | 239 | memerr: |
| donatien | 0:632c9925f013 | 240 | pbuf_free(p); |
| donatien | 0:632c9925f013 | 241 | ICMP_STATS_INC(icmp.err); |
| donatien | 0:632c9925f013 | 242 | snmp_inc_icmpinerrors(); |
| donatien | 0:632c9925f013 | 243 | return; |
| donatien | 0:632c9925f013 | 244 | #endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */ |
| donatien | 0:632c9925f013 | 245 | } |
| donatien | 0:632c9925f013 | 246 | |
| donatien | 0:632c9925f013 | 247 | /** |
| donatien | 0:632c9925f013 | 248 | * Send an icmp 'destination unreachable' packet, called from ip_input() if |
| donatien | 0:632c9925f013 | 249 | * the transport layer protocol is unknown and from udp_input() if the local |
| donatien | 0:632c9925f013 | 250 | * port is not bound. |
| donatien | 0:632c9925f013 | 251 | * |
| donatien | 0:632c9925f013 | 252 | * @param p the input packet for which the 'unreachable' should be sent, |
| donatien | 0:632c9925f013 | 253 | * p->payload pointing to the IP header |
| donatien | 0:632c9925f013 | 254 | * @param t type of the 'unreachable' packet |
| donatien | 0:632c9925f013 | 255 | */ |
| donatien | 0:632c9925f013 | 256 | void |
| donatien | 0:632c9925f013 | 257 | icmp_dest_unreach(struct pbuf *p, enum icmp_dur_type t) |
| donatien | 0:632c9925f013 | 258 | { |
| donatien | 0:632c9925f013 | 259 | icmp_send_response(p, ICMP_DUR, t); |
| donatien | 0:632c9925f013 | 260 | } |
| donatien | 0:632c9925f013 | 261 | |
| donatien | 0:632c9925f013 | 262 | #if IP_FORWARD || IP_REASSEMBLY |
| donatien | 0:632c9925f013 | 263 | /** |
| donatien | 0:632c9925f013 | 264 | * Send a 'time exceeded' packet, called from ip_forward() if TTL is 0. |
| donatien | 0:632c9925f013 | 265 | * |
| donatien | 0:632c9925f013 | 266 | * @param p the input packet for which the 'time exceeded' should be sent, |
| donatien | 0:632c9925f013 | 267 | * p->payload pointing to the IP header |
| donatien | 0:632c9925f013 | 268 | * @param t type of the 'time exceeded' packet |
| donatien | 0:632c9925f013 | 269 | */ |
| donatien | 0:632c9925f013 | 270 | void |
| donatien | 0:632c9925f013 | 271 | icmp_time_exceeded(struct pbuf *p, enum icmp_te_type t) |
| donatien | 0:632c9925f013 | 272 | { |
| donatien | 0:632c9925f013 | 273 | icmp_send_response(p, ICMP_TE, t); |
| donatien | 0:632c9925f013 | 274 | } |
| donatien | 0:632c9925f013 | 275 | |
| donatien | 0:632c9925f013 | 276 | #endif /* IP_FORWARD || IP_REASSEMBLY */ |
| donatien | 0:632c9925f013 | 277 | |
| donatien | 0:632c9925f013 | 278 | /** |
| donatien | 0:632c9925f013 | 279 | * Send an icmp packet in response to an incoming packet. |
| donatien | 0:632c9925f013 | 280 | * |
| donatien | 0:632c9925f013 | 281 | * @param p the input packet for which the 'unreachable' should be sent, |
| donatien | 0:632c9925f013 | 282 | * p->payload pointing to the IP header |
| donatien | 0:632c9925f013 | 283 | * @param type Type of the ICMP header |
| donatien | 0:632c9925f013 | 284 | * @param code Code of the ICMP header |
| donatien | 0:632c9925f013 | 285 | */ |
| donatien | 0:632c9925f013 | 286 | static void |
| donatien | 0:632c9925f013 | 287 | icmp_send_response(struct pbuf *p, u8_t type, u8_t code) |
| donatien | 0:632c9925f013 | 288 | { |
| donatien | 0:632c9925f013 | 289 | struct pbuf *q; |
| donatien | 0:632c9925f013 | 290 | struct ip_hdr *iphdr; |
| donatien | 0:632c9925f013 | 291 | /* we can use the echo header here */ |
| donatien | 0:632c9925f013 | 292 | struct icmp_echo_hdr *icmphdr; |
| donatien | 5:dd63a1e02b1b | 293 | ip_addr_t iphdr_src; |
| donatien | 0:632c9925f013 | 294 | |
| donatien | 0:632c9925f013 | 295 | /* ICMP header + IP header + 8 bytes of data */ |
| donatien | 0:632c9925f013 | 296 | q = pbuf_alloc(PBUF_IP, sizeof(struct icmp_echo_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE, |
| donatien | 0:632c9925f013 | 297 | PBUF_RAM); |
| donatien | 0:632c9925f013 | 298 | if (q == NULL) { |
| donatien | 0:632c9925f013 | 299 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded: failed to allocate pbuf for ICMP packet.\n")); |
| donatien | 0:632c9925f013 | 300 | return; |
| donatien | 0:632c9925f013 | 301 | } |
| donatien | 0:632c9925f013 | 302 | LWIP_ASSERT("check that first pbuf can hold icmp message", |
| donatien | 0:632c9925f013 | 303 | (q->len >= (sizeof(struct icmp_echo_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE))); |
| donatien | 0:632c9925f013 | 304 | |
| donatien | 0:632c9925f013 | 305 | iphdr = (struct ip_hdr *)p->payload; |
| donatien | 0:632c9925f013 | 306 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded from ")); |
| donatien | 0:632c9925f013 | 307 | ip_addr_debug_print(ICMP_DEBUG, &(iphdr->src)); |
| donatien | 0:632c9925f013 | 308 | LWIP_DEBUGF(ICMP_DEBUG, (" to ")); |
| donatien | 0:632c9925f013 | 309 | ip_addr_debug_print(ICMP_DEBUG, &(iphdr->dest)); |
| donatien | 0:632c9925f013 | 310 | LWIP_DEBUGF(ICMP_DEBUG, ("\n")); |
| donatien | 0:632c9925f013 | 311 | |
| donatien | 0:632c9925f013 | 312 | icmphdr = (struct icmp_echo_hdr *)q->payload; |
| donatien | 0:632c9925f013 | 313 | icmphdr->type = type; |
| donatien | 0:632c9925f013 | 314 | icmphdr->code = code; |
| donatien | 0:632c9925f013 | 315 | icmphdr->id = 0; |
| donatien | 0:632c9925f013 | 316 | icmphdr->seqno = 0; |
| donatien | 0:632c9925f013 | 317 | |
| donatien | 0:632c9925f013 | 318 | /* copy fields from original packet */ |
| donatien | 0:632c9925f013 | 319 | SMEMCPY((u8_t *)q->payload + sizeof(struct icmp_echo_hdr), (u8_t *)p->payload, |
| donatien | 0:632c9925f013 | 320 | IP_HLEN + ICMP_DEST_UNREACH_DATASIZE); |
| donatien | 0:632c9925f013 | 321 | |
| donatien | 0:632c9925f013 | 322 | /* calculate checksum */ |
| donatien | 0:632c9925f013 | 323 | icmphdr->chksum = 0; |
| donatien | 0:632c9925f013 | 324 | icmphdr->chksum = inet_chksum(icmphdr, q->len); |
| donatien | 0:632c9925f013 | 325 | ICMP_STATS_INC(icmp.xmit); |
| donatien | 0:632c9925f013 | 326 | /* increase number of messages attempted to send */ |
| donatien | 0:632c9925f013 | 327 | snmp_inc_icmpoutmsgs(); |
| donatien | 0:632c9925f013 | 328 | /* increase number of destination unreachable messages attempted to send */ |
| donatien | 0:632c9925f013 | 329 | snmp_inc_icmpouttimeexcds(); |
| donatien | 5:dd63a1e02b1b | 330 | ip_addr_copy(iphdr_src, iphdr->src); |
| donatien | 5:dd63a1e02b1b | 331 | ip_output(q, NULL, &iphdr_src, ICMP_TTL, 0, IP_PROTO_ICMP); |
| donatien | 0:632c9925f013 | 332 | pbuf_free(q); |
| donatien | 0:632c9925f013 | 333 | } |
| donatien | 0:632c9925f013 | 334 | |
| donatien | 0:632c9925f013 | 335 | #endif /* LWIP_ICMP */ |