ip_icmp.c revision 1.7
1 /* 2 * Copyright (c) 1982, 1986, 1989 Regents of the University of California. 3 * 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 * from: @(#)ip_icmp.c 7.15 (Berkeley) 4/20/91 34 * $Id: ip_icmp.c,v 1.7 1994/01/10 20:14:18 mycroft Exp $ 35 */ 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/malloc.h> 40 #include <sys/mbuf.h> 41 #include <sys/protosw.h> 42 #include <sys/socket.h> 43 #include <sys/time.h> 44 #include <sys/kernel.h> 45 46 #include <net/route.h> 47 #include <net/if.h> 48 49 #include <netinet/in.h> 50 #include <netinet/in_systm.h> 51 #include <netinet/in_var.h> 52 #include <netinet/ip.h> 53 #include <netinet/ip_icmp.h> 54 #include <netinet/icmp_var.h> 55 56 /* 57 * ICMP routines: error generation, receive packet processing, and 58 * routines to turnaround packets back to the originator, and 59 * host table maintenance routines. 60 */ 61 #ifdef ICMPPRINTFS 62 int icmpprintfs = 0; 63 #endif 64 65 extern struct protosw inetsw[]; 66 67 /* 68 * Generate an error packet of type error 69 * in response to bad packet ip. 70 */ 71 /*VARARGS3*/ 72 void 73 icmp_error(n, type, code, dest) 74 struct mbuf *n; 75 int type, code; 76 struct in_addr dest; 77 { 78 register struct ip *oip = mtod(n, struct ip *), *nip; 79 register unsigned oiplen = oip->ip_hl << 2; 80 register struct icmp *icp; 81 register struct mbuf *m; 82 unsigned icmplen; 83 84 #ifdef ICMPPRINTFS 85 if (icmpprintfs) 86 printf("icmp_error(%x, %d, %d)\n", oip, type, code); 87 #endif 88 if (type != ICMP_REDIRECT) 89 icmpstat.icps_error++; 90 /* 91 * Don't send error if not the first fragment of message. 92 * Don't error if the old packet protocol was ICMP 93 * error message, only known informational types. 94 */ 95 if (oip->ip_off &~ (IP_MF|IP_DF)) 96 goto freeit; 97 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && 98 n->m_len >= oiplen + ICMP_MINLEN && 99 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiplen))->icmp_type)) { 100 icmpstat.icps_oldicmp++; 101 goto freeit; 102 } 103 #ifdef MULTICAST 104 /* Don't send error in response to a multicast or broadcast packet */ 105 if (n->m_flags & (M_MCAST | M_BCAST)) 106 goto freeit; 107 #endif 108 /* 109 * First, formulate icmp message 110 */ 111 m = m_gethdr(M_DONTWAIT, MT_HEADER); 112 if (m == NULL) 113 goto freeit; 114 icmplen = oiplen + min(8, oip->ip_len); 115 m->m_len = icmplen + ICMP_MINLEN; 116 MH_ALIGN(m, m->m_len); 117 icp = mtod(m, struct icmp *); 118 if ((u_int)type > ICMP_MAXTYPE) 119 panic("icmp_error"); 120 icmpstat.icps_outhist[type]++; 121 icp->icmp_type = type; 122 if (type == ICMP_REDIRECT) 123 icp->icmp_gwaddr = dest; 124 else 125 icp->icmp_void = 0; 126 if (type == ICMP_PARAMPROB) { 127 icp->icmp_pptr = code; 128 code = 0; 129 } 130 icp->icmp_code = code; 131 bcopy((caddr_t)oip, (caddr_t)&icp->icmp_ip, icmplen); 132 nip = &icp->icmp_ip; 133 nip->ip_len = htons((u_short)(nip->ip_len + oiplen)); 134 135 /* 136 * Now, copy old ip header (without options) 137 * in front of icmp message. 138 */ 139 if (m->m_data - sizeof(struct ip) < m->m_pktdat) 140 panic("icmp len"); 141 m->m_data -= sizeof(struct ip); 142 m->m_len += sizeof(struct ip); 143 m->m_pkthdr.len = m->m_len; 144 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif; 145 nip = mtod(m, struct ip *); 146 bcopy((caddr_t)oip, (caddr_t)nip, oiplen); 147 nip->ip_len = m->m_len; 148 nip->ip_hl = sizeof(struct ip) >> 2; 149 nip->ip_p = IPPROTO_ICMP; 150 icmp_reflect(m); 151 152 freeit: 153 m_freem(n); 154 } 155 156 static struct sockproto icmproto = { AF_INET, IPPROTO_ICMP }; 157 static struct sockaddr_in icmpsrc = { sizeof (struct sockaddr_in), AF_INET }; 158 static struct sockaddr_in icmpdst = { sizeof (struct sockaddr_in), AF_INET }; 159 static struct sockaddr_in icmpgw = { sizeof (struct sockaddr_in), AF_INET }; 160 struct sockaddr_in icmpmask = { 8, 0 }; 161 struct in_ifaddr *ifptoia(); 162 163 /* 164 * Process a received ICMP message. 165 */ 166 void 167 icmp_input(m, hlen) 168 register struct mbuf *m; 169 int hlen; 170 { 171 register struct icmp *icp; 172 register struct ip *ip = mtod(m, struct ip *); 173 int icmplen = ip->ip_len; 174 register int i; 175 struct in_ifaddr *ia; 176 int (*ctlfunc)(), code; 177 extern u_char ip_protox[]; 178 extern struct in_addr in_makeaddr(); 179 180 /* 181 * Locate icmp structure in mbuf, and check 182 * that not corrupted and of at least minimum length. 183 */ 184 #ifdef ICMPPRINTFS 185 if (icmpprintfs) 186 printf("icmp_input from %x, len %d\n", ip->ip_src, icmplen); 187 #endif 188 if (icmplen < ICMP_MINLEN) { 189 icmpstat.icps_tooshort++; 190 goto freeit; 191 } 192 i = hlen + MIN(icmplen, ICMP_ADVLENMIN); 193 if (m->m_len < i && (m = m_pullup(m, i)) == 0) { 194 icmpstat.icps_tooshort++; 195 return; 196 } 197 ip = mtod(m, struct ip *); 198 m->m_len -= hlen; 199 m->m_data += hlen; 200 icp = mtod(m, struct icmp *); 201 if (in_cksum(m, icmplen)) { 202 icmpstat.icps_checksum++; 203 goto freeit; 204 } 205 m->m_len += hlen; 206 m->m_data -= hlen; 207 208 #ifdef ICMPPRINTFS 209 /* 210 * Message type specific processing. 211 */ 212 if (icmpprintfs) 213 printf("icmp_input, type %d code %d\n", icp->icmp_type, 214 icp->icmp_code); 215 #endif 216 if (icp->icmp_type > ICMP_MAXTYPE) 217 goto raw; 218 icmpstat.icps_inhist[icp->icmp_type]++; 219 code = icp->icmp_code; 220 switch (icp->icmp_type) { 221 222 case ICMP_UNREACH: 223 if (code > 5) 224 goto badcode; 225 code += PRC_UNREACH_NET; 226 goto deliver; 227 228 case ICMP_TIMXCEED: 229 if (code > 1) 230 goto badcode; 231 code += PRC_TIMXCEED_INTRANS; 232 goto deliver; 233 234 case ICMP_PARAMPROB: 235 if (code) 236 goto badcode; 237 code = PRC_PARAMPROB; 238 goto deliver; 239 240 case ICMP_SOURCEQUENCH: 241 if (code) 242 goto badcode; 243 code = PRC_QUENCH; 244 deliver: 245 /* 246 * Problem with datagram; advise higher level routines. 247 */ 248 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 249 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 250 icmpstat.icps_badlen++; 251 goto freeit; 252 } 253 NTOHS(icp->icmp_ip.ip_len); 254 #ifdef ICMPPRINTFS 255 if (icmpprintfs) 256 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p); 257 #endif 258 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 259 if (ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput) 260 (*ctlfunc)(code, (struct sockaddr *)&icmpsrc, 261 (caddr_t) &icp->icmp_ip); 262 break; 263 264 badcode: 265 icmpstat.icps_badcode++; 266 break; 267 268 case ICMP_ECHO: 269 icp->icmp_type = ICMP_ECHOREPLY; 270 goto reflect; 271 272 case ICMP_TSTAMP: 273 if (icmplen < ICMP_TSLEN) { 274 icmpstat.icps_badlen++; 275 break; 276 } 277 icp->icmp_type = ICMP_TSTAMPREPLY; 278 icp->icmp_rtime = iptime(); 279 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ 280 goto reflect; 281 282 case ICMP_IREQ: 283 #define satosin(sa) ((struct sockaddr_in *)(sa)) 284 if (in_netof(ip->ip_src) == 0 && 285 (ia = ifptoia(m->m_pkthdr.rcvif))) 286 ip->ip_src = in_makeaddr(in_netof(IA_SIN(ia)->sin_addr), 287 in_lnaof(ip->ip_src)); 288 icp->icmp_type = ICMP_IREQREPLY; 289 goto reflect; 290 291 case ICMP_MASKREQ: 292 if (icmplen < ICMP_MASKLEN || 293 (ia = ifptoia(m->m_pkthdr.rcvif)) == 0) 294 break; 295 icp->icmp_type = ICMP_MASKREPLY; 296 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; 297 if (ip->ip_src.s_addr == 0) { 298 if (ia->ia_ifp->if_flags & IFF_BROADCAST) 299 ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr; 300 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) 301 ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr; 302 } 303 reflect: 304 ip->ip_len += hlen; /* since ip_input deducts this */ 305 icmpstat.icps_reflect++; 306 icmpstat.icps_outhist[icp->icmp_type]++; 307 icmp_reflect(m); 308 return; 309 310 case ICMP_REDIRECT: 311 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp)) { 312 icmpstat.icps_badlen++; 313 break; 314 } 315 /* 316 * Short circuit routing redirects to force 317 * immediate change in the kernel's routing 318 * tables. The message is also handed to anyone 319 * listening on a raw socket (e.g. the routing 320 * daemon for use in updating its tables). 321 */ 322 icmpgw.sin_addr = ip->ip_src; 323 icmpdst.sin_addr = icp->icmp_gwaddr; 324 #ifdef ICMPPRINTFS 325 if (icmpprintfs) 326 printf("redirect dst %x to %x\n", icp->icmp_ip.ip_dst, 327 icp->icmp_gwaddr); 328 #endif 329 if (code == ICMP_REDIRECT_NET || code == ICMP_REDIRECT_TOSNET) { 330 u_long in_netof(); 331 icmpsrc.sin_addr = 332 in_makeaddr(in_netof(icp->icmp_ip.ip_dst), INADDR_ANY); 333 in_sockmaskof(icp->icmp_ip.ip_dst, &icmpmask); 334 rtredirect((struct sockaddr *)&icmpsrc, 335 (struct sockaddr *)&icmpdst, 336 (struct sockaddr *)&icmpmask, RTF_GATEWAY, 337 (struct sockaddr *)&icmpgw, (struct rtentry **)0); 338 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 339 pfctlinput(PRC_REDIRECT_NET, 340 (struct sockaddr *)&icmpsrc); 341 } else { 342 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 343 rtredirect((struct sockaddr *)&icmpsrc, 344 (struct sockaddr *)&icmpdst, 345 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST, 346 (struct sockaddr *)&icmpgw, (struct rtentry **)0); 347 pfctlinput(PRC_REDIRECT_HOST, 348 (struct sockaddr *)&icmpsrc); 349 } 350 break; 351 352 /* 353 * No kernel processing for the following; 354 * just fall through to send to raw listener. 355 */ 356 case ICMP_ECHOREPLY: 357 case ICMP_TSTAMPREPLY: 358 case ICMP_IREQREPLY: 359 case ICMP_MASKREPLY: 360 default: 361 break; 362 } 363 364 raw: 365 icmpsrc.sin_addr = ip->ip_src; 366 icmpdst.sin_addr = ip->ip_dst; 367 (void) raw_input(m, &icmproto, (struct sockaddr *)&icmpsrc, 368 (struct sockaddr *)&icmpdst); 369 return; 370 371 freeit: 372 m_freem(m); 373 } 374 375 /* 376 * Reflect the ip packet back to the source 377 */ 378 void 379 icmp_reflect(m) 380 struct mbuf *m; 381 { 382 register struct ip *ip = mtod(m, struct ip *); 383 register struct in_ifaddr *ia; 384 struct in_addr t; 385 struct mbuf *opts = 0, *ip_srcroute(); 386 int optlen = (ip->ip_hl << 2) - sizeof(struct ip); 387 388 t = ip->ip_dst; 389 ip->ip_dst = ip->ip_src; 390 /* 391 * If the incoming packet was addressed directly to us, 392 * use dst as the src for the reply. Otherwise (broadcast 393 * or anonymous), use the address which corresponds 394 * to the incoming interface. 395 */ 396 for (ia = in_ifaddr; ia; ia = ia->ia_next) { 397 if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr) 398 break; 399 if ((ia->ia_ifp->if_flags & IFF_BROADCAST) && 400 t.s_addr == satosin(&ia->ia_broadaddr)->sin_addr.s_addr) 401 break; 402 } 403 if (ia == (struct in_ifaddr *)0) 404 ia = ifptoia(m->m_pkthdr.rcvif); 405 if (ia == (struct in_ifaddr *)0) 406 ia = in_ifaddr; 407 t = IA_SIN(ia)->sin_addr; 408 ip->ip_src = t; 409 ip->ip_ttl = MAXTTL; 410 411 if (optlen > 0) { 412 register u_char *cp; 413 int opt, cnt; 414 u_int len; 415 416 /* 417 * Retrieve any source routing from the incoming packet; 418 * add on any record-route or timestamp options. 419 */ 420 cp = (u_char *) (ip + 1); 421 if ((opts = ip_srcroute()) == 0 && 422 (opts = m_gethdr(M_DONTWAIT, MT_HEADER))) { 423 opts->m_len = sizeof(struct in_addr); 424 mtod(opts, struct in_addr *)->s_addr = 0; 425 } 426 if (opts) { 427 #ifdef ICMPPRINTFS 428 if (icmpprintfs) 429 printf("icmp_reflect optlen %d rt %d => ", 430 optlen, opts->m_len); 431 #endif 432 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { 433 opt = cp[IPOPT_OPTVAL]; 434 if (opt == IPOPT_EOL) 435 break; 436 if (opt == IPOPT_NOP) 437 len = 1; 438 else { 439 len = cp[IPOPT_OLEN]; 440 if (len <= 0 || len > cnt) 441 break; 442 } 443 /* 444 * should check for overflow, but it "can't happen" 445 */ 446 if (opt == IPOPT_RR || opt == IPOPT_TS) { 447 bcopy((caddr_t)cp, 448 mtod(opts, caddr_t) + opts->m_len, len); 449 opts->m_len += len; 450 } 451 } 452 if (opts->m_len % 4 != 0) { 453 *(mtod(opts, caddr_t) + opts->m_len) = IPOPT_EOL; 454 opts->m_len++; 455 } 456 #ifdef ICMPPRINTFS 457 if (icmpprintfs) 458 printf("%d\n", opts->m_len); 459 #endif 460 } 461 /* 462 * Now strip out original options by copying rest of first 463 * mbuf's data back, and adjust the IP length. 464 */ 465 ip->ip_len -= optlen; 466 ip->ip_hl = sizeof(struct ip) >> 2; 467 m->m_len -= optlen; 468 if (m->m_flags & M_PKTHDR) 469 m->m_pkthdr.len -= optlen; 470 optlen += sizeof(struct ip); 471 bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1), 472 (unsigned)(m->m_len - sizeof(struct ip))); 473 } 474 m->m_flags &= ~(M_BCAST|M_MCAST); 475 icmp_send(m, opts); 476 if (opts) 477 (void)m_free(opts); 478 } 479 480 struct in_ifaddr * 481 ifptoia(ifp) 482 struct ifnet *ifp; 483 { 484 register struct in_ifaddr *ia; 485 486 for (ia = in_ifaddr; ia; ia = ia->ia_next) 487 if (ia->ia_ifp == ifp) 488 return (ia); 489 return ((struct in_ifaddr *)0); 490 } 491 492 /* 493 * Send an icmp packet back to the ip level, 494 * after supplying a checksum. 495 */ 496 void 497 icmp_send(m, opts) 498 register struct mbuf *m; 499 struct mbuf *opts; 500 { 501 register struct ip *ip = mtod(m, struct ip *); 502 register int hlen; 503 register struct icmp *icp; 504 505 hlen = ip->ip_hl << 2; 506 m->m_data += hlen; 507 m->m_len -= hlen; 508 icp = mtod(m, struct icmp *); 509 icp->icmp_cksum = 0; 510 icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen); 511 m->m_data -= hlen; 512 m->m_len += hlen; 513 #ifdef ICMPPRINTFS 514 if (icmpprintfs) 515 printf("icmp_send dst %x src %x\n", ip->ip_dst, ip->ip_src); 516 #endif 517 (void) ip_output(m, opts, NULL, 0, NULL); 518 } 519 520 n_time 521 iptime() 522 { 523 struct timeval atv; 524 u_long t; 525 526 microtime(&atv); 527 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; 528 return (htonl(t)); 529 } 530
Indexes created Tue Sep 23 14:10:03 GMT 2025