ip_icmp.c revision 1.1.1.2
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. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94 34 */ 35 36 #include <sys/param.h> 37 #include <sys/systm.h> 38 #include <sys/malloc.h> 39 #include <sys/mbuf.h> 40 #include <sys/protosw.h> 41 #include <sys/socket.h> 42 #include <sys/time.h> 43 #include <sys/kernel.h> 44 45 #include <net/if.h> 46 #include <net/route.h> 47 48 #include <netinet/in.h> 49 #include <netinet/in_systm.h> 50 #include <netinet/in_var.h> 51 #include <netinet/ip.h> 52 #include <netinet/ip_icmp.h> 53 #include <netinet/icmp_var.h> 54 55 /* 56 * ICMP routines: error generation, receive packet processing, and 57 * routines to turnaround packets back to the originator, and 58 * host table maintenance routines. 59 */ 60 61 int icmpmaskrepl = 0; 62 #ifdef ICMPPRINTFS 63 int icmpprintfs = 0; 64 #endif 65 66 extern struct protosw inetsw[]; 67 68 /* 69 * Generate an error packet of type error 70 * in response to bad packet ip. 71 */ 72 void 73 icmp_error(n, type, code, dest, destifp) 74 struct mbuf *n; 75 int type, code; 76 n_long dest; 77 struct ifnet *destifp; 78 { 79 register struct ip *oip = mtod(n, struct ip *), *nip; 80 register unsigned oiplen = oip->ip_hl << 2; 81 register struct icmp *icp; 82 register struct mbuf *m; 83 unsigned icmplen; 84 85 #ifdef ICMPPRINTFS 86 if (icmpprintfs) 87 printf("icmp_error(%x, %d, %d)\n", oip, type, code); 88 #endif 89 if (type != ICMP_REDIRECT) 90 icmpstat.icps_error++; 91 /* 92 * Don't send error if not the first fragment of message. 93 * Don't error if the old packet protocol was ICMP 94 * error message, only known informational types. 95 */ 96 if (oip->ip_off &~ (IP_MF|IP_DF)) 97 goto freeit; 98 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && 99 n->m_len >= oiplen + ICMP_MINLEN && 100 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiplen))->icmp_type)) { 101 icmpstat.icps_oldicmp++; 102 goto freeit; 103 } 104 /* Don't send error in response to a multicast or broadcast packet */ 105 if (n->m_flags & (M_BCAST|M_MCAST)) 106 goto freeit; 107 /* 108 * First, formulate icmp message 109 */ 110 m = m_gethdr(M_DONTWAIT, MT_HEADER); 111 if (m == NULL) 112 goto freeit; 113 icmplen = oiplen + min(8, oip->ip_len); 114 m->m_len = icmplen + ICMP_MINLEN; 115 MH_ALIGN(m, m->m_len); 116 icp = mtod(m, struct icmp *); 117 if ((u_int)type > ICMP_MAXTYPE) 118 panic("icmp_error"); 119 icmpstat.icps_outhist[type]++; 120 icp->icmp_type = type; 121 if (type == ICMP_REDIRECT) 122 icp->icmp_gwaddr.s_addr = dest; 123 else { 124 icp->icmp_void = 0; 125 /* 126 * The following assignments assume an overlay with the 127 * zeroed icmp_void field. 128 */ 129 if (type == ICMP_PARAMPROB) { 130 icp->icmp_pptr = code; 131 code = 0; 132 } else if (type == ICMP_UNREACH && 133 code == ICMP_UNREACH_NEEDFRAG && destifp) { 134 icp->icmp_nextmtu = htons(destifp->if_mtu); 135 } 136 } 137 138 icp->icmp_code = code; 139 bcopy((caddr_t)oip, (caddr_t)&icp->icmp_ip, icmplen); 140 nip = &icp->icmp_ip; 141 nip->ip_len = htons((u_short)(nip->ip_len + oiplen)); 142 143 /* 144 * Now, copy old ip header (without options) 145 * in front of icmp message. 146 */ 147 if (m->m_data - sizeof(struct ip) < m->m_pktdat) 148 panic("icmp len"); 149 m->m_data -= sizeof(struct ip); 150 m->m_len += sizeof(struct ip); 151 m->m_pkthdr.len = m->m_len; 152 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif; 153 nip = mtod(m, struct ip *); 154 bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip)); 155 nip->ip_len = m->m_len; 156 nip->ip_hl = sizeof(struct ip) >> 2; 157 nip->ip_p = IPPROTO_ICMP; 158 nip->ip_tos = 0; 159 icmp_reflect(m); 160 161 freeit: 162 m_freem(n); 163 } 164 165 static struct sockaddr_in icmpsrc = { sizeof (struct sockaddr_in), AF_INET }; 166 static struct sockaddr_in icmpdst = { sizeof (struct sockaddr_in), AF_INET }; 167 static struct sockaddr_in icmpgw = { sizeof (struct sockaddr_in), AF_INET }; 168 struct sockaddr_in icmpmask = { 8, 0 }; 169 170 /* 171 * Process a received ICMP message. 172 */ 173 void 174 icmp_input(m, hlen) 175 register struct mbuf *m; 176 int hlen; 177 { 178 register struct icmp *icp; 179 register struct ip *ip = mtod(m, struct ip *); 180 int icmplen = ip->ip_len; 181 register int i; 182 struct in_ifaddr *ia; 183 void (*ctlfunc) __P((int, struct sockaddr *, struct ip *)); 184 int code; 185 extern u_char ip_protox[]; 186 187 /* 188 * Locate icmp structure in mbuf, and check 189 * that not corrupted and of at least minimum length. 190 */ 191 #ifdef ICMPPRINTFS 192 if (icmpprintfs) 193 printf("icmp_input from %x to %x, len %d\n", 194 ntohl(ip->ip_src.s_addr), ntohl(ip->ip_dst.s_addr), 195 icmplen); 196 #endif 197 if (icmplen < ICMP_MINLEN) { 198 icmpstat.icps_tooshort++; 199 goto freeit; 200 } 201 i = hlen + min(icmplen, ICMP_ADVLENMIN); 202 if (m->m_len < i && (m = m_pullup(m, i)) == 0) { 203 icmpstat.icps_tooshort++; 204 return; 205 } 206 ip = mtod(m, struct ip *); 207 m->m_len -= hlen; 208 m->m_data += hlen; 209 icp = mtod(m, struct icmp *); 210 if (in_cksum(m, icmplen)) { 211 icmpstat.icps_checksum++; 212 goto freeit; 213 } 214 m->m_len += hlen; 215 m->m_data -= hlen; 216 217 #ifdef ICMPPRINTFS 218 /* 219 * Message type specific processing. 220 */ 221 if (icmpprintfs) 222 printf("icmp_input, type %d code %d\n", icp->icmp_type, 223 icp->icmp_code); 224 #endif 225 if (icp->icmp_type > ICMP_MAXTYPE) 226 goto raw; 227 icmpstat.icps_inhist[icp->icmp_type]++; 228 code = icp->icmp_code; 229 switch (icp->icmp_type) { 230 231 case ICMP_UNREACH: 232 switch (code) { 233 case ICMP_UNREACH_NET: 234 case ICMP_UNREACH_HOST: 235 case ICMP_UNREACH_PROTOCOL: 236 case ICMP_UNREACH_PORT: 237 case ICMP_UNREACH_SRCFAIL: 238 code += PRC_UNREACH_NET; 239 break; 240 241 case ICMP_UNREACH_NEEDFRAG: 242 code = PRC_MSGSIZE; 243 break; 244 245 case ICMP_UNREACH_NET_UNKNOWN: 246 case ICMP_UNREACH_NET_PROHIB: 247 case ICMP_UNREACH_TOSNET: 248 code = PRC_UNREACH_NET; 249 break; 250 251 case ICMP_UNREACH_HOST_UNKNOWN: 252 case ICMP_UNREACH_ISOLATED: 253 case ICMP_UNREACH_HOST_PROHIB: 254 case ICMP_UNREACH_TOSHOST: 255 code = PRC_UNREACH_HOST; 256 break; 257 258 default: 259 goto badcode; 260 } 261 goto deliver; 262 263 case ICMP_TIMXCEED: 264 if (code > 1) 265 goto badcode; 266 code += PRC_TIMXCEED_INTRANS; 267 goto deliver; 268 269 case ICMP_PARAMPROB: 270 if (code > 1) 271 goto badcode; 272 code = PRC_PARAMPROB; 273 goto deliver; 274 275 case ICMP_SOURCEQUENCH: 276 if (code) 277 goto badcode; 278 code = PRC_QUENCH; 279 deliver: 280 /* 281 * Problem with datagram; advise higher level routines. 282 */ 283 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 284 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 285 icmpstat.icps_badlen++; 286 goto freeit; 287 } 288 NTOHS(icp->icmp_ip.ip_len); 289 #ifdef ICMPPRINTFS 290 if (icmpprintfs) 291 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p); 292 #endif 293 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 294 if (ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput) 295 (*ctlfunc)(code, (struct sockaddr *)&icmpsrc, 296 &icp->icmp_ip); 297 break; 298 299 badcode: 300 icmpstat.icps_badcode++; 301 break; 302 303 case ICMP_ECHO: 304 icp->icmp_type = ICMP_ECHOREPLY; 305 goto reflect; 306 307 case ICMP_TSTAMP: 308 if (icmplen < ICMP_TSLEN) { 309 icmpstat.icps_badlen++; 310 break; 311 } 312 icp->icmp_type = ICMP_TSTAMPREPLY; 313 icp->icmp_rtime = iptime(); 314 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ 315 goto reflect; 316 317 case ICMP_MASKREQ: 318 #define satosin(sa) ((struct sockaddr_in *)(sa)) 319 if (icmpmaskrepl == 0) 320 break; 321 /* 322 * We are not able to respond with all ones broadcast 323 * unless we receive it over a point-to-point interface. 324 */ 325 if (icmplen < ICMP_MASKLEN) 326 break; 327 switch (ip->ip_dst.s_addr) { 328 329 case INADDR_BROADCAST: 330 case INADDR_ANY: 331 icmpdst.sin_addr = ip->ip_src; 332 break; 333 334 default: 335 icmpdst.sin_addr = ip->ip_dst; 336 } 337 ia = (struct in_ifaddr *)ifaof_ifpforaddr( 338 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif); 339 if (ia == 0) 340 break; 341 icp->icmp_type = ICMP_MASKREPLY; 342 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; 343 if (ip->ip_src.s_addr == 0) { 344 if (ia->ia_ifp->if_flags & IFF_BROADCAST) 345 ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr; 346 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) 347 ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr; 348 } 349 reflect: 350 ip->ip_len += hlen; /* since ip_input deducts this */ 351 icmpstat.icps_reflect++; 352 icmpstat.icps_outhist[icp->icmp_type]++; 353 icmp_reflect(m); 354 return; 355 356 case ICMP_REDIRECT: 357 if (code > 3) 358 goto badcode; 359 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 360 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 361 icmpstat.icps_badlen++; 362 break; 363 } 364 /* 365 * Short circuit routing redirects to force 366 * immediate change in the kernel's routing 367 * tables. The message is also handed to anyone 368 * listening on a raw socket (e.g. the routing 369 * daemon for use in updating its tables). 370 */ 371 icmpgw.sin_addr = ip->ip_src; 372 icmpdst.sin_addr = icp->icmp_gwaddr; 373 #ifdef ICMPPRINTFS 374 if (icmpprintfs) 375 printf("redirect dst %x to %x\n", icp->icmp_ip.ip_dst, 376 icp->icmp_gwaddr); 377 #endif 378 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 379 rtredirect((struct sockaddr *)&icmpsrc, 380 (struct sockaddr *)&icmpdst, 381 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST, 382 (struct sockaddr *)&icmpgw, (struct rtentry **)0); 383 pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc); 384 break; 385 386 /* 387 * No kernel processing for the following; 388 * just fall through to send to raw listener. 389 */ 390 case ICMP_ECHOREPLY: 391 case ICMP_ROUTERADVERT: 392 case ICMP_ROUTERSOLICIT: 393 case ICMP_TSTAMPREPLY: 394 case ICMP_IREQREPLY: 395 case ICMP_MASKREPLY: 396 default: 397 break; 398 } 399 400 raw: 401 rip_input(m); 402 return; 403 404 freeit: 405 m_freem(m); 406 } 407 408 /* 409 * Reflect the ip packet back to the source 410 */ 411 void 412 icmp_reflect(m) 413 struct mbuf *m; 414 { 415 register struct ip *ip = mtod(m, struct ip *); 416 register struct in_ifaddr *ia; 417 struct in_addr t; 418 struct mbuf *opts = 0, *ip_srcroute(); 419 int optlen = (ip->ip_hl << 2) - sizeof(struct ip); 420 421 if (!in_canforward(ip->ip_src) && 422 ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) != 423 (IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) { 424 m_freem(m); /* Bad return address */ 425 goto done; /* Ip_output() will check for broadcast */ 426 } 427 t = ip->ip_dst; 428 ip->ip_dst = ip->ip_src; 429 /* 430 * If the incoming packet was addressed directly to us, 431 * use dst as the src for the reply. Otherwise (broadcast 432 * or anonymous), use the address which corresponds 433 * to the incoming interface. 434 */ 435 for (ia = in_ifaddr; ia; ia = ia->ia_next) { 436 if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr) 437 break; 438 if ((ia->ia_ifp->if_flags & IFF_BROADCAST) && 439 t.s_addr == satosin(&ia->ia_broadaddr)->sin_addr.s_addr) 440 break; 441 } 442 icmpdst.sin_addr = t; 443 if (ia == (struct in_ifaddr *)0) 444 ia = (struct in_ifaddr *)ifaof_ifpforaddr( 445 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif); 446 /* 447 * The following happens if the packet was not addressed to us, 448 * and was received on an interface with no IP address. 449 */ 450 if (ia == (struct in_ifaddr *)0) 451 ia = in_ifaddr; 452 t = IA_SIN(ia)->sin_addr; 453 ip->ip_src = t; 454 ip->ip_ttl = MAXTTL; 455 456 if (optlen > 0) { 457 register u_char *cp; 458 int opt, cnt; 459 u_int len; 460 461 /* 462 * Retrieve any source routing from the incoming packet; 463 * add on any record-route or timestamp options. 464 */ 465 cp = (u_char *) (ip + 1); 466 if ((opts = ip_srcroute()) == 0 && 467 (opts = m_gethdr(M_DONTWAIT, MT_HEADER))) { 468 opts->m_len = sizeof(struct in_addr); 469 mtod(opts, struct in_addr *)->s_addr = 0; 470 } 471 if (opts) { 472 #ifdef ICMPPRINTFS 473 if (icmpprintfs) 474 printf("icmp_reflect optlen %d rt %d => ", 475 optlen, opts->m_len); 476 #endif 477 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { 478 opt = cp[IPOPT_OPTVAL]; 479 if (opt == IPOPT_EOL) 480 break; 481 if (opt == IPOPT_NOP) 482 len = 1; 483 else { 484 len = cp[IPOPT_OLEN]; 485 if (len <= 0 || len > cnt) 486 break; 487 } 488 /* 489 * Should check for overflow, but it "can't happen" 490 */ 491 if (opt == IPOPT_RR || opt == IPOPT_TS || 492 opt == IPOPT_SECURITY) { 493 bcopy((caddr_t)cp, 494 mtod(opts, caddr_t) + opts->m_len, len); 495 opts->m_len += len; 496 } 497 } 498 /* Terminate & pad, if necessary */ 499 if (cnt = opts->m_len % 4) { 500 for (; cnt < 4; cnt++) { 501 *(mtod(opts, caddr_t) + opts->m_len) = 502 IPOPT_EOL; 503 opts->m_len++; 504 } 505 } 506 #ifdef ICMPPRINTFS 507 if (icmpprintfs) 508 printf("%d\n", opts->m_len); 509 #endif 510 } 511 /* 512 * Now strip out original options by copying rest of first 513 * mbuf's data back, and adjust the IP length. 514 */ 515 ip->ip_len -= optlen; 516 ip->ip_hl = sizeof(struct ip) >> 2; 517 m->m_len -= optlen; 518 if (m->m_flags & M_PKTHDR) 519 m->m_pkthdr.len -= optlen; 520 optlen += sizeof(struct ip); 521 bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1), 522 (unsigned)(m->m_len - sizeof(struct ip))); 523 } 524 m->m_flags &= ~(M_BCAST|M_MCAST); 525 icmp_send(m, opts); 526 done: 527 if (opts) 528 (void)m_free(opts); 529 } 530 531 /* 532 * Send an icmp packet back to the ip level, 533 * after supplying a checksum. 534 */ 535 void 536 icmp_send(m, opts) 537 register struct mbuf *m; 538 struct mbuf *opts; 539 { 540 register struct ip *ip = mtod(m, struct ip *); 541 register int hlen; 542 register struct icmp *icp; 543 544 hlen = ip->ip_hl << 2; 545 m->m_data += hlen; 546 m->m_len -= hlen; 547 icp = mtod(m, struct icmp *); 548 icp->icmp_cksum = 0; 549 icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen); 550 m->m_data -= hlen; 551 m->m_len += hlen; 552 #ifdef ICMPPRINTFS 553 if (icmpprintfs) 554 printf("icmp_send dst %x src %x\n", ip->ip_dst, ip->ip_src); 555 #endif 556 (void) ip_output(m, opts, NULL, 0, NULL); 557 } 558 559 n_time 560 iptime() 561 { 562 struct timeval atv; 563 u_long t; 564 565 microtime(&atv); 566 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; 567 return (htonl(t)); 568 } 569 570 int 571 icmp_sysctl(name, namelen, oldp, oldlenp, newp, newlen) 572 int *name; 573 u_int namelen; 574 void *oldp; 575 size_t *oldlenp; 576 void *newp; 577 size_t newlen; 578 { 579 580 /* All sysctl names at this level are terminal. */ 581 if (namelen != 1) 582 return (ENOTDIR); 583 584 switch (name[0]) { 585 case ICMPCTL_MASKREPL: 586 return (sysctl_int(oldp, oldlenp, newp, newlen, &icmpmaskrepl)); 587 default: 588 return (ENOPROTOOPT); 589 } 590 /* NOTREACHED */ 591 } 592
Indexes created Fri Oct 03 02:09:57 GMT 2025