The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 1982, 1986, 1988, 1993 |
| 3 | * The Regents of the University of California. All rights reserved. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions |
| 7 | * are met: |
| 8 | * 1. Redistributions of source code must retain the above copyright |
| 9 | * notice, this list of conditions and the following disclaimer. |
| 10 | * 2. Redistributions in binary form must reproduce the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer in the |
| 12 | * documentation and/or other materials provided with the distribution. |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 13 | * 3. Neither the name of the University nor the names of its contributors |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 14 | * may be used to endorse or promote products derived from this software |
| 15 | * without specific prior written permission. |
| 16 | * |
| 17 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 27 | * SUCH DAMAGE. |
| 28 | * |
| 29 | * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94 |
| 30 | * ip_icmp.c,v 1.7 1995/05/30 08:09:42 rgrimes Exp |
| 31 | */ |
| 32 | |
| 33 | #include "slirp.h" |
| 34 | #include "ip_icmp.h" |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 35 | |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 36 | #ifdef LOG_ENABLED |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 37 | struct icmpstat icmpstat; |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 38 | #endif |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 39 | |
| 40 | /* The message sent when emulating PING */ |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 41 | /* Be nice and tell them it's just a pseudo-ping packet */ |
| 42 | static const char icmp_ping_msg[] = "This is a pseudo-PING packet used by Slirp to emulate ICMP ECHO-REQUEST packets.\n"; |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 43 | |
| 44 | /* list of actions for icmp_error() on RX of an icmp message */ |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 45 | static const int icmp_flush[19] = { |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 46 | /* ECHO REPLY (0) */ 0, |
| 47 | 1, |
| 48 | 1, |
| 49 | /* DEST UNREACH (3) */ 1, |
| 50 | /* SOURCE QUENCH (4)*/ 1, |
| 51 | /* REDIRECT (5) */ 1, |
| 52 | 1, |
| 53 | 1, |
| 54 | /* ECHO (8) */ 0, |
| 55 | /* ROUTERADVERT (9) */ 1, |
| 56 | /* ROUTERSOLICIT (10) */ 1, |
| 57 | /* TIME EXCEEDED (11) */ 1, |
| 58 | /* PARAMETER PROBLEM (12) */ 1, |
| 59 | /* TIMESTAMP (13) */ 0, |
| 60 | /* TIMESTAMP REPLY (14) */ 0, |
| 61 | /* INFO (15) */ 0, |
| 62 | /* INFO REPLY (16) */ 0, |
| 63 | /* ADDR MASK (17) */ 0, |
| 64 | /* ADDR MASK REPLY (18) */ 0 |
| 65 | }; |
| 66 | |
| 67 | /* |
| 68 | * Process a received ICMP message. |
| 69 | */ |
| 70 | void |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 71 | icmp_input(struct mbuf *m, int hlen) |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 72 | { |
| 73 | register struct icmp *icp; |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 74 | register struct ip *ip=mtod(m, struct ip *); |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 75 | int icmplen=ip->ip_len; |
| 76 | /* int code; */ |
| 77 | |
| 78 | DEBUG_CALL("icmp_input"); |
| 79 | DEBUG_ARG("m = %lx", (long )m); |
| 80 | DEBUG_ARG("m_len = %d", m->m_len); |
| 81 | |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 82 | STAT(icmpstat.icps_received++); |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 83 | |
| 84 | /* |
| 85 | * Locate icmp structure in mbuf, and check |
| 86 | * that its not corrupted and of at least minimum length. |
| 87 | */ |
| 88 | if (icmplen < ICMP_MINLEN) { /* min 8 bytes payload */ |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 89 | STAT(icmpstat.icps_tooshort++); |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 90 | freeit: |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 91 | m_freem(m); |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 92 | goto end_error; |
| 93 | } |
| 94 | |
| 95 | m->m_len -= hlen; |
| 96 | m->m_data += hlen; |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 97 | icp = mtod(m, struct icmp *); |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 98 | if (cksum(m, icmplen)) { |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 99 | STAT(icmpstat.icps_checksum++); |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 100 | goto freeit; |
| 101 | } |
| 102 | m->m_len += hlen; |
| 103 | m->m_data -= hlen; |
| 104 | |
| 105 | /* icmpstat.icps_inhist[icp->icmp_type]++; */ |
| 106 | /* code = icp->icmp_code; */ |
| 107 | |
| 108 | DEBUG_ARG("icmp_type = %d", icp->icmp_type); |
| 109 | switch (icp->icmp_type) { |
| 110 | case ICMP_ECHO: |
| 111 | icp->icmp_type = ICMP_ECHOREPLY; |
| 112 | ip->ip_len += hlen; /* since ip_input subtracts this */ |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 113 | if (ip->ip_dst.s_addr == alias_addr.s_addr) { |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 114 | icmp_reflect(m); |
| 115 | } else { |
| 116 | struct socket *so; |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 117 | struct sockaddr_in addr; |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 118 | if ((so = socreate()) == NULL) goto freeit; |
| 119 | if(udp_attach(so) == -1) { |
| 120 | DEBUG_MISC((dfd,"icmp_input udp_attach errno = %d-%s\n", |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 121 | errno,strerror(errno))); |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 122 | sofree(so); |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 123 | m_free(m); |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 124 | goto end_error; |
| 125 | } |
| 126 | so->so_m = m; |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 127 | so->so_faddr = ip->ip_dst; |
| 128 | so->so_fport = htons(7); |
| 129 | so->so_laddr = ip->ip_src; |
| 130 | so->so_lport = htons(9); |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 131 | so->so_iptos = ip->ip_tos; |
| 132 | so->so_type = IPPROTO_ICMP; |
| 133 | so->so_state = SS_ISFCONNECTED; |
| 134 | |
| 135 | /* Send the packet */ |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 136 | addr.sin_family = AF_INET; |
| 137 | if ((so->so_faddr.s_addr & htonl(0xffffff00)) == special_addr.s_addr) { |
| 138 | /* It's an alias */ |
| 139 | switch(ntohl(so->so_faddr.s_addr) & 0xff) { |
| 140 | case CTL_DNS: |
| 141 | addr.sin_addr = dns_addr; |
| 142 | break; |
| 143 | case CTL_ALIAS: |
| 144 | default: |
| 145 | addr.sin_addr = loopback_addr; |
| 146 | break; |
| 147 | } |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 148 | } else { |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 149 | addr.sin_addr = so->so_faddr; |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 150 | } |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 151 | addr.sin_port = so->so_fport; |
| 152 | if(sendto(so->s, icmp_ping_msg, strlen(icmp_ping_msg), 0, |
| 153 | (struct sockaddr *)&addr, sizeof(addr)) == -1) { |
| 154 | DEBUG_MISC((dfd,"icmp_input udp sendto tx errno = %d-%s\n", |
| 155 | errno,strerror(errno))); |
| 156 | icmp_error(m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,strerror(errno)); |
| 157 | udp_detach(so); |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 158 | } |
| 159 | } /* if ip->ip_dst.s_addr == alias_addr.s_addr */ |
| 160 | break; |
| 161 | case ICMP_UNREACH: |
| 162 | /* XXX? report error? close socket? */ |
| 163 | case ICMP_TIMXCEED: |
| 164 | case ICMP_PARAMPROB: |
| 165 | case ICMP_SOURCEQUENCH: |
| 166 | case ICMP_TSTAMP: |
| 167 | case ICMP_MASKREQ: |
| 168 | case ICMP_REDIRECT: |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 169 | STAT(icmpstat.icps_notsupp++); |
| 170 | m_freem(m); |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 171 | break; |
| 172 | |
| 173 | default: |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 174 | STAT(icmpstat.icps_badtype++); |
| 175 | m_freem(m); |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 176 | } /* swith */ |
| 177 | |
| 178 | end_error: |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 179 | /* m is m_free()'d xor put in a socket xor or given to ip_send */ |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 180 | return; |
| 181 | } |
| 182 | |
| 183 | |
| 184 | /* |
| 185 | * Send an ICMP message in response to a situation |
| 186 | * |
| 187 | * RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header. MAY send more (we do). |
| 188 | * MUST NOT change this header information. |
| 189 | * MUST NOT reply to a multicast/broadcast IP address. |
| 190 | * MUST NOT reply to a multicast/broadcast MAC address. |
| 191 | * MUST reply to only the first fragment. |
| 192 | */ |
| 193 | /* |
| 194 | * Send ICMP_UNREACH back to the source regarding msrc. |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 195 | * mbuf *msrc is used as a template, but is NOT m_free()'d. |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 196 | * It is reported as the bad ip packet. The header should |
| 197 | * be fully correct and in host byte order. |
| 198 | * ICMP fragmentation is illegal. All machines must accept 576 bytes in one |
| 199 | * packet. The maximum payload is 576-20(ip hdr)-8(icmp hdr)=548 |
| 200 | */ |
| 201 | |
| 202 | #define ICMP_MAXDATALEN (IP_MSS-28) |
| 203 | void |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 204 | icmp_error(struct mbuf *msrc, u_char type, u_char code, int minsize, |
| 205 | const char *message) |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 206 | { |
| 207 | unsigned hlen, shlen, s_ip_len; |
| 208 | register struct ip *ip; |
| 209 | register struct icmp *icp; |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 210 | register struct mbuf *m; |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 211 | |
| 212 | DEBUG_CALL("icmp_error"); |
| 213 | DEBUG_ARG("msrc = %lx", (long )msrc); |
| 214 | DEBUG_ARG("msrc_len = %d", msrc->m_len); |
| 215 | |
| 216 | if(type!=ICMP_UNREACH && type!=ICMP_TIMXCEED) goto end_error; |
| 217 | |
| 218 | /* check msrc */ |
| 219 | if(!msrc) goto end_error; |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 220 | ip = mtod(msrc, struct ip *); |
| 221 | #ifdef DEBUG |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 222 | { char bufa[20], bufb[20]; |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 223 | strcpy(bufa, inet_ntoa(ip->ip_src)); |
| 224 | strcpy(bufb, inet_ntoa(ip->ip_dst)); |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 225 | DEBUG_MISC((dfd, " %.16s to %.16s\n", bufa, bufb)); |
| 226 | } |
| 227 | #endif |
| 228 | if(ip->ip_off & IP_OFFMASK) goto end_error; /* Only reply to fragment 0 */ |
| 229 | |
| 230 | shlen=ip->ip_hl << 2; |
| 231 | s_ip_len=ip->ip_len; |
| 232 | if(ip->ip_p == IPPROTO_ICMP) { |
| 233 | icp = (struct icmp *)((char *)ip + shlen); |
| 234 | /* |
| 235 | * Assume any unknown ICMP type is an error. This isn't |
| 236 | * specified by the RFC, but think about it.. |
| 237 | */ |
| 238 | if(icp->icmp_type>18 || icmp_flush[icp->icmp_type]) goto end_error; |
| 239 | } |
| 240 | |
| 241 | /* make a copy */ |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 242 | if(!(m=m_get())) goto end_error; /* get mbuf */ |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 243 | { int new_m_size; |
| 244 | new_m_size=sizeof(struct ip )+ICMP_MINLEN+msrc->m_len+ICMP_MAXDATALEN; |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 245 | if(new_m_size>m->m_size) m_inc(m, new_m_size); |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 246 | } |
| 247 | memcpy(m->m_data, msrc->m_data, msrc->m_len); |
| 248 | m->m_len = msrc->m_len; /* copy msrc to m */ |
| 249 | |
| 250 | /* make the header of the reply packet */ |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 251 | ip = mtod(m, struct ip *); |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 252 | hlen= sizeof(struct ip ); /* no options in reply */ |
| 253 | |
| 254 | /* fill in icmp */ |
| 255 | m->m_data += hlen; |
| 256 | m->m_len -= hlen; |
| 257 | |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 258 | icp = mtod(m, struct icmp *); |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 259 | |
| 260 | if(minsize) s_ip_len=shlen+ICMP_MINLEN; /* return header+8b only */ |
| 261 | else if(s_ip_len>ICMP_MAXDATALEN) /* maximum size */ |
| 262 | s_ip_len=ICMP_MAXDATALEN; |
| 263 | |
| 264 | m->m_len=ICMP_MINLEN+s_ip_len; /* 8 bytes ICMP header */ |
| 265 | |
| 266 | /* min. size = 8+sizeof(struct ip)+8 */ |
| 267 | |
| 268 | icp->icmp_type = type; |
| 269 | icp->icmp_code = code; |
| 270 | icp->icmp_id = 0; |
| 271 | icp->icmp_seq = 0; |
| 272 | |
| 273 | memcpy(&icp->icmp_ip, msrc->m_data, s_ip_len); /* report the ip packet */ |
| 274 | HTONS(icp->icmp_ip.ip_len); |
| 275 | HTONS(icp->icmp_ip.ip_id); |
| 276 | HTONS(icp->icmp_ip.ip_off); |
| 277 | |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 278 | #ifdef DEBUG |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 279 | if(message) { /* DEBUG : append message to ICMP packet */ |
| 280 | int message_len; |
| 281 | char *cpnt; |
| 282 | message_len=strlen(message); |
| 283 | if(message_len>ICMP_MAXDATALEN) message_len=ICMP_MAXDATALEN; |
| 284 | cpnt=(char *)m->m_data+m->m_len; |
| 285 | memcpy(cpnt, message, message_len); |
| 286 | m->m_len+=message_len; |
| 287 | } |
| 288 | #endif |
| 289 | |
| 290 | icp->icmp_cksum = 0; |
| 291 | icp->icmp_cksum = cksum(m, m->m_len); |
| 292 | |
| 293 | m->m_data -= hlen; |
| 294 | m->m_len += hlen; |
| 295 | |
| 296 | /* fill in ip */ |
| 297 | ip->ip_hl = hlen >> 2; |
| 298 | ip->ip_len = m->m_len; |
| 299 | |
| 300 | ip->ip_tos=((ip->ip_tos & 0x1E) | 0xC0); /* high priority for errors */ |
| 301 | |
| 302 | ip->ip_ttl = MAXTTL; |
| 303 | ip->ip_p = IPPROTO_ICMP; |
| 304 | ip->ip_dst = ip->ip_src; /* ip adresses */ |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 305 | ip->ip_src = alias_addr; |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 306 | |
| 307 | (void ) ip_output((struct socket *)NULL, m); |
| 308 | |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 309 | STAT(icmpstat.icps_reflect++); |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 310 | |
| 311 | end_error: |
| 312 | return; |
| 313 | } |
| 314 | #undef ICMP_MAXDATALEN |
| 315 | |
| 316 | /* |
| 317 | * Reflect the ip packet back to the source |
| 318 | */ |
| 319 | void |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 320 | icmp_reflect(struct mbuf *m) |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 321 | { |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 322 | register struct ip *ip = mtod(m, struct ip *); |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 323 | int hlen = ip->ip_hl << 2; |
| 324 | int optlen = hlen - sizeof(struct ip ); |
| 325 | register struct icmp *icp; |
| 326 | |
| 327 | /* |
| 328 | * Send an icmp packet back to the ip level, |
| 329 | * after supplying a checksum. |
| 330 | */ |
| 331 | m->m_data += hlen; |
| 332 | m->m_len -= hlen; |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 333 | icp = mtod(m, struct icmp *); |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 334 | |
| 335 | icp->icmp_cksum = 0; |
| 336 | icp->icmp_cksum = cksum(m, ip->ip_len - hlen); |
| 337 | |
| 338 | m->m_data -= hlen; |
| 339 | m->m_len += hlen; |
| 340 | |
| 341 | /* fill in ip */ |
| 342 | if (optlen > 0) { |
| 343 | /* |
| 344 | * Strip out original options by copying rest of first |
| 345 | * mbuf's data back, and adjust the IP length. |
| 346 | */ |
| 347 | memmove((caddr_t)(ip + 1), (caddr_t)ip + hlen, |
| 348 | (unsigned )(m->m_len - hlen)); |
| 349 | hlen -= optlen; |
| 350 | ip->ip_hl = hlen >> 2; |
| 351 | ip->ip_len -= optlen; |
| 352 | m->m_len -= optlen; |
| 353 | } |
| 354 | |
| 355 | ip->ip_ttl = MAXTTL; |
| 356 | { /* swap */ |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 357 | struct in_addr icmp_dst; |
| 358 | icmp_dst = ip->ip_dst; |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 359 | ip->ip_dst = ip->ip_src; |
| 360 | ip->ip_src = icmp_dst; |
| 361 | } |
| 362 | |
| 363 | (void ) ip_output((struct socket *)NULL, m); |
| 364 | |
David 'Digit' Turner | 5d8f37a | 2009-09-14 14:32:27 -0700 | [diff] [blame] | 365 | STAT(icmpstat.icps_reflect++); |
The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 366 | } |