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 * $FreeBSD: src/sys/netinet/ip_icmp.c,v 1.39.2.19 2003/01/24 05:11:34 sam Exp $ 35 * $DragonFly: src/sys/netinet/ip_icmp.c,v 1.22 2005/03/06 05:09:25 hsu Exp $ 36 */ 37 38 #include "opt_ipsec.h" 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/mbuf.h> 43 #include <sys/protosw.h> 44 #include <sys/socket.h> 45 #include <sys/time.h> 46 #include <sys/kernel.h> 47 #include <sys/sysctl.h> 48 #include <sys/in_cksum.h> 49 50 #include <machine/stdarg.h> 51 52 #include <net/if.h> 53 #include <net/if_types.h> 54 #include <net/route.h> 55 56 #define _IP_VHL 57 #include <netinet/in.h> 58 #include <netinet/in_systm.h> 59 #include <netinet/in_var.h> 60 #include <netinet/ip.h> 61 #include <netinet/ip_icmp.h> 62 #include <netinet/ip_var.h> 63 #include <netinet/icmp_var.h> 64 65 #ifdef IPSEC 66 #include <netinet6/ipsec.h> 67 #include <netproto/key/key.h> 68 #endif 69 70 #ifdef FAST_IPSEC 71 #include <netproto/ipsec/ipsec.h> 72 #include <netproto/ipsec/key.h> 73 #define IPSEC 74 #endif 75 76 /* 77 * ICMP routines: error generation, receive packet processing, and 78 * routines to turnaround packets back to the originator, and 79 * host table maintenance routines. 80 */ 81 82 struct icmpstat icmpstat; 83 SYSCTL_STRUCT(_net_inet_icmp, ICMPCTL_STATS, stats, CTLFLAG_RW, 84 &icmpstat, icmpstat, ""); 85 86 static int icmpmaskrepl = 0; 87 SYSCTL_INT(_net_inet_icmp, ICMPCTL_MASKREPL, maskrepl, CTLFLAG_RW, 88 &icmpmaskrepl, 0, ""); 89 90 static int drop_redirect = 0; 91 SYSCTL_INT(_net_inet_icmp, OID_AUTO, drop_redirect, CTLFLAG_RW, 92 &drop_redirect, 0, ""); 93 94 static int log_redirect = 0; 95 SYSCTL_INT(_net_inet_icmp, OID_AUTO, log_redirect, CTLFLAG_RW, 96 &log_redirect, 0, ""); 97 98 #ifdef ICMP_BANDLIM 99 100 /* 101 * ICMP error-response bandwidth limiting sysctl. If not enabled, sysctl 102 * variable content is -1 and read-only. 103 */ 104 105 static int icmplim = 200; 106 SYSCTL_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_RW, 107 &icmplim, 0, ""); 108 #else 109 110 static int icmplim = -1; 111 SYSCTL_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_RD, 112 &icmplim, 0, ""); 113 114 #endif 115 116 static int icmplim_output = 1; 117 SYSCTL_INT(_net_inet_icmp, OID_AUTO, icmplim_output, CTLFLAG_RW, 118 &icmplim_output, 0, ""); 119 120 /* 121 * ICMP broadcast echo sysctl 122 */ 123 124 static int icmpbmcastecho = 0; 125 SYSCTL_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_RW, 126 &icmpbmcastecho, 0, ""); 127 128 129 #ifdef ICMPPRINTFS 130 int icmpprintfs = 0; 131 #endif 132 133 static void icmp_reflect (struct mbuf *); 134 static void icmp_send (struct mbuf *, struct mbuf *, struct route *); 135 136 extern struct protosw inetsw[]; 137 138 /* 139 * Generate an error packet of type error 140 * in response to bad packet ip. 141 */ 142 void 143 icmp_error(n, type, code, dest, destifp) 144 struct mbuf *n; 145 int type, code; 146 n_long dest; 147 struct ifnet *destifp; 148 { 149 struct ip *oip = mtod(n, struct ip *), *nip; 150 unsigned oiplen = IP_VHL_HL(oip->ip_vhl) << 2; 151 struct icmp *icp; 152 struct mbuf *m; 153 unsigned icmplen; 154 155 #ifdef ICMPPRINTFS 156 if (icmpprintfs) 157 printf("icmp_error(%p, %x, %d)\n", oip, type, code); 158 #endif 159 if (type != ICMP_REDIRECT) 160 icmpstat.icps_error++; 161 /* 162 * Don't send error if the original packet was encrypted. 163 * Don't send error if not the first fragment of message. 164 * Don't error if the old packet protocol was ICMP 165 * error message, only known informational types. 166 */ 167 if (n->m_flags & M_DECRYPTED) 168 goto freeit; 169 if (oip->ip_off &~ (IP_MF|IP_DF)) 170 goto freeit; 171 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && 172 n->m_len >= oiplen + ICMP_MINLEN && 173 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiplen))->icmp_type)) { 174 icmpstat.icps_oldicmp++; 175 goto freeit; 176 } 177 /* Don't send error in response to a multicast or broadcast packet */ 178 if (n->m_flags & (M_BCAST|M_MCAST)) 179 goto freeit; 180 /* 181 * First, formulate icmp message 182 */ 183 m = m_gethdr(MB_DONTWAIT, MT_HEADER); 184 if (m == NULL) 185 goto freeit; 186 icmplen = min(oiplen + 8, oip->ip_len); 187 if (icmplen < sizeof(struct ip)) 188 panic("icmp_error: bad length"); 189 m->m_len = icmplen + ICMP_MINLEN; 190 MH_ALIGN(m, m->m_len); 191 icp = mtod(m, struct icmp *); 192 if ((u_int)type > ICMP_MAXTYPE) 193 panic("icmp_error"); 194 icmpstat.icps_outhist[type]++; 195 icp->icmp_type = type; 196 if (type == ICMP_REDIRECT) 197 icp->icmp_gwaddr.s_addr = dest; 198 else { 199 icp->icmp_void = 0; 200 /* 201 * The following assignments assume an overlay with the 202 * zeroed icmp_void field. 203 */ 204 if (type == ICMP_PARAMPROB) { 205 icp->icmp_pptr = code; 206 code = 0; 207 } else if (type == ICMP_UNREACH && 208 code == ICMP_UNREACH_NEEDFRAG && destifp) { 209 icp->icmp_nextmtu = htons(destifp->if_mtu); 210 } 211 } 212 213 icp->icmp_code = code; 214 m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip); 215 nip = &icp->icmp_ip; 216 217 /* 218 * Convert fields to network representation. 219 */ 220 nip->ip_len = htons(nip->ip_len); 221 nip->ip_off = htons(nip->ip_off); 222 223 /* 224 * Now, copy old ip header (without options) 225 * in front of icmp message. 226 */ 227 if (m->m_data - sizeof(struct ip) < m->m_pktdat) 228 panic("icmp len"); 229 m->m_data -= sizeof(struct ip); 230 m->m_len += sizeof(struct ip); 231 m->m_pkthdr.len = m->m_len; 232 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif; 233 nip = mtod(m, struct ip *); 234 bcopy(oip, nip, sizeof(struct ip)); 235 nip->ip_len = m->m_len; 236 nip->ip_vhl = IP_VHL_BORING; 237 nip->ip_p = IPPROTO_ICMP; 238 nip->ip_tos = 0; 239 m->m_pkthdr.fw_flags |= n->m_pkthdr.fw_flags & PF_MBUF_GENERATED; 240 icmp_reflect(m); 241 242 freeit: 243 m_freem(n); 244 } 245 246 /* 247 * Process a received ICMP message. 248 */ 249 void 250 icmp_input(struct mbuf *m, ...) 251 { 252 struct sockaddr_in icmpsrc = { sizeof(struct sockaddr_in), AF_INET }; 253 struct sockaddr_in icmpdst = { sizeof(struct sockaddr_in), AF_INET }; 254 struct sockaddr_in icmpgw = { sizeof(struct sockaddr_in), AF_INET }; 255 struct icmp *icp; 256 struct in_ifaddr *ia; 257 struct ip *ip = mtod(m, struct ip *); 258 void (*ctlfunc) (int, struct sockaddr *, void *); 259 int icmplen = ip->ip_len; 260 int i, hlen; 261 int code, off, proto; 262 __va_list ap; 263 264 __va_start(ap, m); 265 off = __va_arg(ap, int); 266 proto = __va_arg(ap, int); 267 __va_end(ap); 268 269 hlen = off; 270 271 /* 272 * Locate icmp structure in mbuf, and check 273 * that not corrupted and of at least minimum length. 274 */ 275 #ifdef ICMPPRINTFS 276 if (icmpprintfs) { 277 char buf[sizeof "aaa.bbb.ccc.ddd"]; 278 279 strcpy(buf, inet_ntoa(ip->ip_src)); 280 printf("icmp_input from %s to %s, len %d\n", 281 buf, inet_ntoa(ip->ip_dst), icmplen); 282 } 283 #endif 284 if (icmplen < ICMP_MINLEN) { 285 icmpstat.icps_tooshort++; 286 goto freeit; 287 } 288 i = hlen + min(icmplen, ICMP_ADVLENMIN); 289 if (m->m_len < i && (m = m_pullup(m, i)) == 0) { 290 icmpstat.icps_tooshort++; 291 return; 292 } 293 ip = mtod(m, struct ip *); 294 m->m_len -= hlen; 295 m->m_data += hlen; 296 icp = mtod(m, struct icmp *); 297 if (in_cksum(m, icmplen)) { 298 icmpstat.icps_checksum++; 299 goto freeit; 300 } 301 m->m_len += hlen; 302 m->m_data -= hlen; 303 304 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 305 /* 306 * Deliver very specific ICMP type only. 307 */ 308 switch (icp->icmp_type) { 309 case ICMP_UNREACH: 310 case ICMP_TIMXCEED: 311 break; 312 default: 313 goto freeit; 314 } 315 } 316 317 #ifdef ICMPPRINTFS 318 if (icmpprintfs) 319 printf("icmp_input, type %d code %d\n", icp->icmp_type, 320 icp->icmp_code); 321 #endif 322 323 /* 324 * Message type specific processing. 325 */ 326 if (icp->icmp_type > ICMP_MAXTYPE) 327 goto raw; 328 icmpstat.icps_inhist[icp->icmp_type]++; 329 code = icp->icmp_code; 330 switch (icp->icmp_type) { 331 332 case ICMP_UNREACH: 333 switch (code) { 334 case ICMP_UNREACH_NET: 335 case ICMP_UNREACH_HOST: 336 case ICMP_UNREACH_SRCFAIL: 337 case ICMP_UNREACH_NET_UNKNOWN: 338 case ICMP_UNREACH_HOST_UNKNOWN: 339 case ICMP_UNREACH_ISOLATED: 340 case ICMP_UNREACH_TOSNET: 341 case ICMP_UNREACH_TOSHOST: 342 case ICMP_UNREACH_HOST_PRECEDENCE: 343 case ICMP_UNREACH_PRECEDENCE_CUTOFF: 344 code = PRC_UNREACH_NET; 345 break; 346 347 case ICMP_UNREACH_NEEDFRAG: 348 code = PRC_MSGSIZE; 349 break; 350 351 /* 352 * RFC 1122, Sections 3.2.2.1 and 4.2.3.9. 353 * Treat subcodes 2,3 as immediate RST 354 */ 355 case ICMP_UNREACH_PROTOCOL: 356 case ICMP_UNREACH_PORT: 357 code = PRC_UNREACH_PORT; 358 break; 359 360 case ICMP_UNREACH_NET_PROHIB: 361 case ICMP_UNREACH_HOST_PROHIB: 362 case ICMP_UNREACH_FILTER_PROHIB: 363 code = PRC_UNREACH_ADMIN_PROHIB; 364 break; 365 366 default: 367 goto badcode; 368 } 369 goto deliver; 370 371 case ICMP_TIMXCEED: 372 if (code > 1) 373 goto badcode; 374 code += PRC_TIMXCEED_INTRANS; 375 goto deliver; 376 377 case ICMP_PARAMPROB: 378 if (code > 1) 379 goto badcode; 380 code = PRC_PARAMPROB; 381 goto deliver; 382 383 case ICMP_SOURCEQUENCH: 384 if (code) 385 goto badcode; 386 code = PRC_QUENCH; 387 deliver: 388 /* 389 * Problem with datagram; advise higher level routines. 390 */ 391 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 392 IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) { 393 icmpstat.icps_badlen++; 394 goto freeit; 395 } 396 icp->icmp_ip.ip_len = ntohs(icp->icmp_ip.ip_len); 397 /* Discard ICMP's in response to multicast packets */ 398 if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr))) 399 goto badcode; 400 #ifdef ICMPPRINTFS 401 if (icmpprintfs) 402 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p); 403 #endif 404 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 405 #if 1 406 /* 407 * MTU discovery: 408 * If we got a needfrag and there is a host route to the 409 * original destination, and the MTU is not locked, then 410 * set the MTU in the route to the suggested new value 411 * (if given) and then notify as usual. The ULPs will 412 * notice that the MTU has changed and adapt accordingly. 413 * If no new MTU was suggested, then we guess a new one 414 * less than the current value. If the new MTU is 415 * unreasonably small (arbitrarily set at 296), then 416 * we reset the MTU to the interface value and enable the 417 * lock bit, indicating that we are no longer doing MTU 418 * discovery. 419 */ 420 if (code == PRC_MSGSIZE) { 421 struct rtentry *rt; 422 int mtu; 423 424 rt = rtpurelookup((struct sockaddr *)&icmpsrc); 425 if (rt != NULL && (rt->rt_flags & RTF_HOST) && 426 !(rt->rt_rmx.rmx_locks & RTV_MTU)) { 427 mtu = ntohs(icp->icmp_nextmtu); 428 if (!mtu) 429 mtu = ip_next_mtu(rt->rt_rmx.rmx_mtu, 430 1); 431 #ifdef DEBUG_MTUDISC 432 printf("MTU for %s reduced to %d\n", 433 inet_ntoa(icmpsrc.sin_addr), mtu); 434 #endif 435 if (mtu < 296) { 436 /* rt->rt_rmx.rmx_mtu = 437 rt->rt_ifp->if_mtu; */ 438 rt->rt_rmx.rmx_locks |= RTV_MTU; 439 } else if (rt->rt_rmx.rmx_mtu > mtu) { 440 rt->rt_rmx.rmx_mtu = mtu; 441 } 442 } 443 if (rt != NULL) 444 --rt->rt_refcnt; 445 } 446 #endif 447 /* 448 * XXX if the packet contains [IPv4 AH TCP], we can't make a 449 * notification to TCP layer. 450 */ 451 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput; 452 if (ctlfunc) 453 (*ctlfunc)(code, (struct sockaddr *)&icmpsrc, 454 &icp->icmp_ip); 455 break; 456 457 badcode: 458 icmpstat.icps_badcode++; 459 break; 460 461 case ICMP_ECHO: 462 if (!icmpbmcastecho 463 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) { 464 icmpstat.icps_bmcastecho++; 465 break; 466 } 467 icp->icmp_type = ICMP_ECHOREPLY; 468 #ifdef ICMP_BANDLIM 469 if (badport_bandlim(BANDLIM_ICMP_ECHO) < 0) 470 goto freeit; 471 else 472 #endif 473 goto reflect; 474 475 case ICMP_TSTAMP: 476 if (!icmpbmcastecho 477 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) { 478 icmpstat.icps_bmcasttstamp++; 479 break; 480 } 481 if (icmplen < ICMP_TSLEN) { 482 icmpstat.icps_badlen++; 483 break; 484 } 485 icp->icmp_type = ICMP_TSTAMPREPLY; 486 icp->icmp_rtime = iptime(); 487 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ 488 #ifdef ICMP_BANDLIM 489 if (badport_bandlim(BANDLIM_ICMP_TSTAMP) < 0) 490 goto freeit; 491 else 492 #endif 493 goto reflect; 494 495 case ICMP_MASKREQ: 496 if (icmpmaskrepl == 0) 497 break; 498 /* 499 * We are not able to respond with all ones broadcast 500 * unless we receive it over a point-to-point interface. 501 */ 502 if (icmplen < ICMP_MASKLEN) 503 break; 504 switch (ip->ip_dst.s_addr) { 505 506 case INADDR_BROADCAST: 507 case INADDR_ANY: 508 icmpdst.sin_addr = ip->ip_src; 509 break; 510 511 default: 512 icmpdst.sin_addr = ip->ip_dst; 513 } 514 ia = (struct in_ifaddr *)ifaof_ifpforaddr( 515 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif); 516 if (ia == 0) 517 break; 518 if (ia->ia_ifp == 0) 519 break; 520 icp->icmp_type = ICMP_MASKREPLY; 521 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; 522 if (ip->ip_src.s_addr == 0) { 523 if (ia->ia_ifp->if_flags & IFF_BROADCAST) 524 ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr; 525 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) 526 ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr; 527 } 528 reflect: 529 ip->ip_len += hlen; /* since ip_input deducts this */ 530 icmpstat.icps_reflect++; 531 icmpstat.icps_outhist[icp->icmp_type]++; 532 icmp_reflect(m); 533 return; 534 535 case ICMP_REDIRECT: 536 if (log_redirect) { 537 u_long src, dst, gw; 538 539 src = ntohl(ip->ip_src.s_addr); 540 dst = ntohl(icp->icmp_ip.ip_dst.s_addr); 541 gw = ntohl(icp->icmp_gwaddr.s_addr); 542 printf("icmp redirect from %d.%d.%d.%d: " 543 "%d.%d.%d.%d => %d.%d.%d.%d\n", 544 (int)(src >> 24), (int)((src >> 16) & 0xff), 545 (int)((src >> 8) & 0xff), (int)(src & 0xff), 546 (int)(dst >> 24), (int)((dst >> 16) & 0xff), 547 (int)((dst >> 8) & 0xff), (int)(dst & 0xff), 548 (int)(gw >> 24), (int)((gw >> 16) & 0xff), 549 (int)((gw >> 8) & 0xff), (int)(gw & 0xff)); 550 } 551 if (drop_redirect) 552 break; 553 if (code > 3) 554 goto badcode; 555 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 556 IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) { 557 icmpstat.icps_badlen++; 558 break; 559 } 560 /* 561 * Short circuit routing redirects to force 562 * immediate change in the kernel's routing 563 * tables. The message is also handed to anyone 564 * listening on a raw socket (e.g. the routing 565 * daemon for use in updating its tables). 566 */ 567 icmpgw.sin_addr = ip->ip_src; 568 icmpdst.sin_addr = icp->icmp_gwaddr; 569 #ifdef ICMPPRINTFS 570 if (icmpprintfs) { 571 char buf[sizeof "aaa.bbb.ccc.ddd"]; 572 573 strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst)); 574 printf("redirect dst %s to %s\n", 575 buf, inet_ntoa(icp->icmp_gwaddr)); 576 } 577 #endif 578 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 579 rtredirect((struct sockaddr *)&icmpsrc, 580 (struct sockaddr *)&icmpdst, 581 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST, 582 (struct sockaddr *)&icmpgw); 583 pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc); 584 #ifdef IPSEC 585 key_sa_routechange((struct sockaddr *)&icmpsrc); 586 #endif 587 break; 588 589 /* 590 * No kernel processing for the following; 591 * just fall through to send to raw listener. 592 */ 593 case ICMP_ECHOREPLY: 594 case ICMP_ROUTERADVERT: 595 case ICMP_ROUTERSOLICIT: 596 case ICMP_TSTAMPREPLY: 597 case ICMP_IREQREPLY: 598 case ICMP_MASKREPLY: 599 default: 600 break; 601 } 602 603 raw: 604 rip_input(m, off, proto); 605 return; 606 607 freeit: 608 m_freem(m); 609 } 610 611 /* 612 * Reflect the ip packet back to the source 613 */ 614 static void 615 icmp_reflect(m) 616 struct mbuf *m; 617 { 618 struct ip *ip = mtod(m, struct ip *); 619 struct ifaddr *ifa; 620 struct in_ifaddr *ia; 621 struct in_addr t; 622 struct mbuf *opts = 0; 623 int optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 624 struct route *ro = NULL, rt; 625 626 if (!in_canforward(ip->ip_src) && 627 ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) != 628 (IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) { 629 m_freem(m); /* Bad return address */ 630 icmpstat.icps_badaddr++; 631 goto done; /* Ip_output() will check for broadcast */ 632 } 633 t = ip->ip_dst; 634 ip->ip_dst = ip->ip_src; 635 ro = &rt; 636 bzero(ro, sizeof *ro); 637 /* 638 * If the incoming packet was addressed directly to us, 639 * use dst as the src for the reply. Otherwise (broadcast 640 * or anonymous), use the address which corresponds 641 * to the incoming interface. 642 */ 643 LIST_FOREACH(ia, INADDR_HASH(t.s_addr), ia_hash) 644 if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr) 645 goto match; 646 if (m->m_pkthdr.rcvif != NULL && 647 m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 648 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 649 if (ifa->ifa_addr->sa_family != AF_INET) 650 continue; 651 ia = ifatoia(ifa); 652 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 653 t.s_addr) 654 goto match; 655 } 656 } 657 ia = ip_rtaddr(ip->ip_dst, ro); 658 /* We need a route to do anything useful. */ 659 if (ia == NULL) { 660 m_freem(m); 661 icmpstat.icps_noroute++; 662 goto done; 663 } 664 match: 665 t = IA_SIN(ia)->sin_addr; 666 ip->ip_src = t; 667 ip->ip_ttl = ip_defttl; 668 669 if (optlen > 0) { 670 u_char *cp; 671 int opt, cnt; 672 u_int len; 673 674 /* 675 * Retrieve any source routing from the incoming packet; 676 * add on any record-route or timestamp options. 677 */ 678 cp = (u_char *) (ip + 1); 679 if ((opts = ip_srcroute()) == 0 && 680 (opts = m_gethdr(MB_DONTWAIT, MT_HEADER))) { 681 opts->m_len = sizeof(struct in_addr); 682 mtod(opts, struct in_addr *)->s_addr = 0; 683 } 684 if (opts) { 685 #ifdef ICMPPRINTFS 686 if (icmpprintfs) 687 printf("icmp_reflect optlen %d rt %d => ", 688 optlen, opts->m_len); 689 #endif 690 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { 691 opt = cp[IPOPT_OPTVAL]; 692 if (opt == IPOPT_EOL) 693 break; 694 if (opt == IPOPT_NOP) 695 len = 1; 696 else { 697 if (cnt < IPOPT_OLEN + sizeof *cp) 698 break; 699 len = cp[IPOPT_OLEN]; 700 if (len < IPOPT_OLEN + sizeof *cp || 701 len > cnt) 702 break; 703 } 704 /* 705 * Should check for overflow, but it 706 * "can't happen". 707 */ 708 if (opt == IPOPT_RR || opt == IPOPT_TS || 709 opt == IPOPT_SECURITY) { 710 bcopy(cp, 711 mtod(opts, caddr_t) + opts->m_len, 712 len); 713 opts->m_len += len; 714 } 715 } 716 /* Terminate & pad, if necessary */ 717 cnt = opts->m_len % 4; 718 if (cnt) { 719 for (; cnt < 4; cnt++) { 720 *(mtod(opts, caddr_t) + opts->m_len) = 721 IPOPT_EOL; 722 opts->m_len++; 723 } 724 } 725 #ifdef ICMPPRINTFS 726 if (icmpprintfs) 727 printf("%d\n", opts->m_len); 728 #endif 729 } 730 /* 731 * Now strip out original options by copying rest of first 732 * mbuf's data back, and adjust the IP length. 733 */ 734 ip->ip_len -= optlen; 735 ip->ip_vhl = IP_VHL_BORING; 736 m->m_len -= optlen; 737 if (m->m_flags & M_PKTHDR) 738 m->m_pkthdr.len -= optlen; 739 optlen += sizeof(struct ip); 740 bcopy((caddr_t)ip + optlen, ip + 1, 741 m->m_len - sizeof(struct ip)); 742 } 743 m->m_pkthdr.fw_flags &= PF_MBUF_GENERATED; 744 m->m_flags &= ~(M_BCAST|M_MCAST); 745 icmp_send(m, opts, ro); 746 done: 747 if (opts) 748 m_free(opts); 749 if (ro && ro->ro_rt) 750 RTFREE(ro->ro_rt); 751 } 752 753 /* 754 * Send an icmp packet back to the ip level, 755 * after supplying a checksum. 756 */ 757 static void 758 icmp_send(m, opts, rt) 759 struct mbuf *m; 760 struct mbuf *opts; 761 struct route *rt; 762 { 763 struct ip *ip = mtod(m, struct ip *); 764 int hlen; 765 struct icmp *icp; 766 767 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 768 m->m_data += hlen; 769 m->m_len -= hlen; 770 icp = mtod(m, struct icmp *); 771 icp->icmp_cksum = 0; 772 icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen); 773 m->m_data -= hlen; 774 m->m_len += hlen; 775 m->m_pkthdr.rcvif = (struct ifnet *)0; 776 #ifdef ICMPPRINTFS 777 if (icmpprintfs) { 778 char buf[sizeof "aaa.bbb.ccc.ddd"]; 779 780 strcpy(buf, inet_ntoa(ip->ip_dst)); 781 printf("icmp_send dst %s src %s\n", buf, inet_ntoa(ip->ip_src)); 782 } 783 #endif 784 ip_output(m, opts, rt, 0, NULL, NULL); 785 } 786 787 n_time 788 iptime() 789 { 790 struct timeval atv; 791 u_long t; 792 793 getmicrotime(&atv); 794 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; 795 return (htonl(t)); 796 } 797 798 #if 1 799 /* 800 * Return the next larger or smaller MTU plateau (table from RFC 1191) 801 * given current value MTU. If DIR is less than zero, a larger plateau 802 * is returned; otherwise, a smaller value is returned. 803 */ 804 int 805 ip_next_mtu(int mtu, int dir) 806 { 807 static int mtutab[] = { 808 65535, 32000, 17914, 8166, 4352, 2002, 1492, 1006, 508, 296, 809 68, 0 810 }; 811 int i; 812 813 for (i = 0; i < (sizeof mtutab) / (sizeof mtutab[0]); i++) { 814 if (mtu >= mtutab[i]) 815 break; 816 } 817 818 if (dir < 0) { 819 if (i == 0) { 820 return 0; 821 } else { 822 return mtutab[i - 1]; 823 } 824 } else { 825 if (mtutab[i] == 0) { 826 return 0; 827 } else if(mtu > mtutab[i]) { 828 return mtutab[i]; 829 } else { 830 return mtutab[i + 1]; 831 } 832 } 833 } 834 #endif 835 836 #ifdef ICMP_BANDLIM 837 /* 838 * badport_bandlim() - check for ICMP bandwidth limit 839 * 840 * Return 0 if it is ok to send an ICMP error response, -1 if we have 841 * hit our bandwidth limit and it is not ok. 842 * 843 * If icmplim is <= 0, the feature is disabled and 0 is returned. 844 * 845 * For now we separate the TCP and UDP subsystems w/ different 'which' 846 * values. We may eventually remove this separation (and simplify the 847 * code further). 848 * 849 * Note that the printing of the error message is delayed so we can 850 * properly print the icmp error rate that the system was trying to do 851 * (i.e. 22000/100 pps, etc...). This can cause long delays in printing 852 * the 'final' error, but it doesn't make sense to solve the printing 853 * delay with more complex code. 854 */ 855 int 856 badport_bandlim(int which) 857 { 858 static int lticks[BANDLIM_MAX + 1]; 859 static int lpackets[BANDLIM_MAX + 1]; 860 int dticks; 861 const char *bandlimittype[] = { 862 "Limiting icmp unreach response", 863 "Limiting icmp ping response", 864 "Limiting icmp tstamp response", 865 "Limiting closed port RST response", 866 "Limiting open port RST response" 867 }; 868 869 /* 870 * Return ok status if feature disabled or argument out of 871 * ranage. 872 */ 873 874 if (icmplim <= 0 || which > BANDLIM_MAX || which < 0) 875 return(0); 876 dticks = ticks - lticks[which]; 877 878 /* 879 * reset stats when cumulative dt exceeds one second. 880 */ 881 882 if ((unsigned int)dticks > hz) { 883 if (lpackets[which] > icmplim && icmplim_output) { 884 printf("%s from %d to %d packets per second\n", 885 bandlimittype[which], 886 lpackets[which], 887 icmplim 888 ); 889 } 890 lticks[which] = ticks; 891 lpackets[which] = 0; 892 } 893 894 /* 895 * bump packet count 896 */ 897 898 if (++lpackets[which] > icmplim) { 899 return(-1); 900 } 901 return(0); 902 } 903 #endif 904