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 1.19 2005/01/06 17:59:32 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 static int ip_next_mtu (int, int); 136 137 extern struct protosw inetsw[]; 138 139 /* 140 * Generate an error packet of type error 141 * in response to bad packet ip. 142 */ 143 void 144 icmp_error(n, type, code, dest, destifp) 145 struct mbuf *n; 146 int type, code; 147 n_long dest; 148 struct ifnet *destifp; 149 { 150 struct ip *oip = mtod(n, struct ip *), *nip; 151 unsigned oiplen = IP_VHL_HL(oip->ip_vhl) << 2; 152 struct icmp *icp; 153 struct mbuf *m; 154 unsigned icmplen; 155 156 #ifdef ICMPPRINTFS 157 if (icmpprintfs) 158 printf("icmp_error(%p, %x, %d)\n", oip, type, code); 159 #endif 160 if (type != ICMP_REDIRECT) 161 icmpstat.icps_error++; 162 /* 163 * Don't send error if the original packet was encrypted. 164 * Don't send error if not the first fragment of message. 165 * Don't error if the old packet protocol was ICMP 166 * error message, only known informational types. 167 */ 168 if (n->m_flags & M_DECRYPTED) 169 goto freeit; 170 if (oip->ip_off &~ (IP_MF|IP_DF)) 171 goto freeit; 172 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && 173 n->m_len >= oiplen + ICMP_MINLEN && 174 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiplen))->icmp_type)) { 175 icmpstat.icps_oldicmp++; 176 goto freeit; 177 } 178 /* Don't send error in response to a multicast or broadcast packet */ 179 if (n->m_flags & (M_BCAST|M_MCAST)) 180 goto freeit; 181 /* 182 * First, formulate icmp message 183 */ 184 m = m_gethdr(MB_DONTWAIT, MT_HEADER); 185 if (m == NULL) 186 goto freeit; 187 icmplen = min(oiplen + 8, oip->ip_len); 188 if (icmplen < sizeof(struct ip)) 189 panic("icmp_error: bad length"); 190 m->m_len = icmplen + ICMP_MINLEN; 191 MH_ALIGN(m, m->m_len); 192 icp = mtod(m, struct icmp *); 193 if ((u_int)type > ICMP_MAXTYPE) 194 panic("icmp_error"); 195 icmpstat.icps_outhist[type]++; 196 icp->icmp_type = type; 197 if (type == ICMP_REDIRECT) 198 icp->icmp_gwaddr.s_addr = dest; 199 else { 200 icp->icmp_void = 0; 201 /* 202 * The following assignments assume an overlay with the 203 * zeroed icmp_void field. 204 */ 205 if (type == ICMP_PARAMPROB) { 206 icp->icmp_pptr = code; 207 code = 0; 208 } else if (type == ICMP_UNREACH && 209 code == ICMP_UNREACH_NEEDFRAG && destifp) { 210 icp->icmp_nextmtu = htons(destifp->if_mtu); 211 } 212 } 213 214 icp->icmp_code = code; 215 m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip); 216 nip = &icp->icmp_ip; 217 218 /* 219 * Convert fields to network representation. 220 */ 221 nip->ip_len = htons(nip->ip_len); 222 nip->ip_off = htons(nip->ip_off); 223 224 /* 225 * Now, copy old ip header (without options) 226 * in front of icmp message. 227 */ 228 if (m->m_data - sizeof(struct ip) < m->m_pktdat) 229 panic("icmp len"); 230 m->m_data -= sizeof(struct ip); 231 m->m_len += sizeof(struct ip); 232 m->m_pkthdr.len = m->m_len; 233 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif; 234 nip = mtod(m, struct ip *); 235 bcopy(oip, nip, sizeof(struct ip)); 236 nip->ip_len = m->m_len; 237 nip->ip_vhl = IP_VHL_BORING; 238 nip->ip_p = IPPROTO_ICMP; 239 nip->ip_tos = 0; 240 m->m_pkthdr.pf_flags |= n->m_pkthdr.pf_flags & PF_MBUF_GENERATED; 241 icmp_reflect(m); 242 243 freeit: 244 m_freem(n); 245 } 246 247 /* 248 * Process a received ICMP message. 249 */ 250 void 251 icmp_input(struct mbuf *m, ...) 252 { 253 struct sockaddr_in icmpsrc = { sizeof(struct sockaddr_in), AF_INET }; 254 struct sockaddr_in icmpdst = { sizeof(struct sockaddr_in), AF_INET }; 255 struct sockaddr_in icmpgw = { sizeof(struct sockaddr_in), AF_INET }; 256 struct icmp *icp; 257 struct in_ifaddr *ia; 258 struct ip *ip = mtod(m, struct ip *); 259 void (*ctlfunc) (int, struct sockaddr *, void *); 260 int icmplen = ip->ip_len; 261 int i, hlen; 262 int code, off, proto; 263 __va_list ap; 264 265 __va_start(ap, m); 266 off = __va_arg(ap, int); 267 proto = __va_arg(ap, int); 268 __va_end(ap); 269 270 hlen = off; 271 272 /* 273 * Locate icmp structure in mbuf, and check 274 * that not corrupted and of at least minimum length. 275 */ 276 #ifdef ICMPPRINTFS 277 if (icmpprintfs) { 278 char buf[sizeof "aaa.bbb.ccc.ddd"]; 279 280 strcpy(buf, inet_ntoa(ip->ip_src)); 281 printf("icmp_input from %s to %s, len %d\n", 282 buf, inet_ntoa(ip->ip_dst), icmplen); 283 } 284 #endif 285 if (icmplen < ICMP_MINLEN) { 286 icmpstat.icps_tooshort++; 287 goto freeit; 288 } 289 i = hlen + min(icmplen, ICMP_ADVLENMIN); 290 if (m->m_len < i && (m = m_pullup(m, i)) == 0) { 291 icmpstat.icps_tooshort++; 292 return; 293 } 294 ip = mtod(m, struct ip *); 295 m->m_len -= hlen; 296 m->m_data += hlen; 297 icp = mtod(m, struct icmp *); 298 if (in_cksum(m, icmplen)) { 299 icmpstat.icps_checksum++; 300 goto freeit; 301 } 302 m->m_len += hlen; 303 m->m_data -= hlen; 304 305 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 306 /* 307 * Deliver very specific ICMP type only. 308 */ 309 switch (icp->icmp_type) { 310 case ICMP_UNREACH: 311 case ICMP_TIMXCEED: 312 break; 313 default: 314 goto freeit; 315 } 316 } 317 318 #ifdef ICMPPRINTFS 319 if (icmpprintfs) 320 printf("icmp_input, type %d code %d\n", icp->icmp_type, 321 icp->icmp_code); 322 #endif 323 324 /* 325 * Message type specific processing. 326 */ 327 if (icp->icmp_type > ICMP_MAXTYPE) 328 goto raw; 329 icmpstat.icps_inhist[icp->icmp_type]++; 330 code = icp->icmp_code; 331 switch (icp->icmp_type) { 332 333 case ICMP_UNREACH: 334 switch (code) { 335 case ICMP_UNREACH_NET: 336 case ICMP_UNREACH_HOST: 337 case ICMP_UNREACH_SRCFAIL: 338 case ICMP_UNREACH_NET_UNKNOWN: 339 case ICMP_UNREACH_HOST_UNKNOWN: 340 case ICMP_UNREACH_ISOLATED: 341 case ICMP_UNREACH_TOSNET: 342 case ICMP_UNREACH_TOSHOST: 343 case ICMP_UNREACH_HOST_PRECEDENCE: 344 case ICMP_UNREACH_PRECEDENCE_CUTOFF: 345 code = PRC_UNREACH_NET; 346 break; 347 348 case ICMP_UNREACH_NEEDFRAG: 349 code = PRC_MSGSIZE; 350 break; 351 352 /* 353 * RFC 1122, Sections 3.2.2.1 and 4.2.3.9. 354 * Treat subcodes 2,3 as immediate RST 355 */ 356 case ICMP_UNREACH_PROTOCOL: 357 case ICMP_UNREACH_PORT: 358 code = PRC_UNREACH_PORT; 359 break; 360 361 case ICMP_UNREACH_NET_PROHIB: 362 case ICMP_UNREACH_HOST_PROHIB: 363 case ICMP_UNREACH_FILTER_PROHIB: 364 code = PRC_UNREACH_ADMIN_PROHIB; 365 break; 366 367 default: 368 goto badcode; 369 } 370 goto deliver; 371 372 case ICMP_TIMXCEED: 373 if (code > 1) 374 goto badcode; 375 code += PRC_TIMXCEED_INTRANS; 376 goto deliver; 377 378 case ICMP_PARAMPROB: 379 if (code > 1) 380 goto badcode; 381 code = PRC_PARAMPROB; 382 goto deliver; 383 384 case ICMP_SOURCEQUENCH: 385 if (code) 386 goto badcode; 387 code = PRC_QUENCH; 388 deliver: 389 /* 390 * Problem with datagram; advise higher level routines. 391 */ 392 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 393 IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) { 394 icmpstat.icps_badlen++; 395 goto freeit; 396 } 397 icp->icmp_ip.ip_len = ntohs(icp->icmp_ip.ip_len); 398 /* Discard ICMP's in response to multicast packets */ 399 if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr))) 400 goto badcode; 401 #ifdef ICMPPRINTFS 402 if (icmpprintfs) 403 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p); 404 #endif 405 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 406 #if 1 407 /* 408 * MTU discovery: 409 * If we got a needfrag and there is a host route to the 410 * original destination, and the MTU is not locked, then 411 * set the MTU in the route to the suggested new value 412 * (if given) and then notify as usual. The ULPs will 413 * notice that the MTU has changed and adapt accordingly. 414 * If no new MTU was suggested, then we guess a new one 415 * less than the current value. If the new MTU is 416 * unreasonably small (arbitrarily set at 296), then 417 * we reset the MTU to the interface value and enable the 418 * lock bit, indicating that we are no longer doing MTU 419 * discovery. 420 */ 421 if (code == PRC_MSGSIZE) { 422 struct rtentry *rt; 423 int mtu; 424 425 rt = rtpurelookup((struct sockaddr *)&icmpsrc); 426 if (rt != NULL && (rt->rt_flags & RTF_HOST) && 427 !(rt->rt_rmx.rmx_locks & RTV_MTU)) { 428 mtu = ntohs(icp->icmp_nextmtu); 429 if (!mtu) 430 mtu = ip_next_mtu(rt->rt_rmx.rmx_mtu, 431 1); 432 #ifdef DEBUG_MTUDISC 433 printf("MTU for %s reduced to %d\n", 434 inet_ntoa(icmpsrc.sin_addr), mtu); 435 #endif 436 if (mtu < 296) { 437 /* rt->rt_rmx.rmx_mtu = 438 rt->rt_ifp->if_mtu; */ 439 rt->rt_rmx.rmx_locks |= RTV_MTU; 440 } else if (rt->rt_rmx.rmx_mtu > mtu) { 441 rt->rt_rmx.rmx_mtu = mtu; 442 } 443 } 444 if (rt != NULL) 445 --rt->rt_refcnt; 446 } 447 448 #endif 449 /* 450 * XXX if the packet contains [IPv4 AH TCP], we can't make a 451 * notification to TCP layer. 452 */ 453 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput; 454 if (ctlfunc) 455 (*ctlfunc)(code, (struct sockaddr *)&icmpsrc, 456 &icp->icmp_ip); 457 break; 458 459 badcode: 460 icmpstat.icps_badcode++; 461 break; 462 463 case ICMP_ECHO: 464 if (!icmpbmcastecho 465 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) { 466 icmpstat.icps_bmcastecho++; 467 break; 468 } 469 icp->icmp_type = ICMP_ECHOREPLY; 470 #ifdef ICMP_BANDLIM 471 if (badport_bandlim(BANDLIM_ICMP_ECHO) < 0) 472 goto freeit; 473 else 474 #endif 475 goto reflect; 476 477 case ICMP_TSTAMP: 478 if (!icmpbmcastecho 479 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) { 480 icmpstat.icps_bmcasttstamp++; 481 break; 482 } 483 if (icmplen < ICMP_TSLEN) { 484 icmpstat.icps_badlen++; 485 break; 486 } 487 icp->icmp_type = ICMP_TSTAMPREPLY; 488 icp->icmp_rtime = iptime(); 489 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ 490 #ifdef ICMP_BANDLIM 491 if (badport_bandlim(BANDLIM_ICMP_TSTAMP) < 0) 492 goto freeit; 493 else 494 #endif 495 goto reflect; 496 497 case ICMP_MASKREQ: 498 if (icmpmaskrepl == 0) 499 break; 500 /* 501 * We are not able to respond with all ones broadcast 502 * unless we receive it over a point-to-point interface. 503 */ 504 if (icmplen < ICMP_MASKLEN) 505 break; 506 switch (ip->ip_dst.s_addr) { 507 508 case INADDR_BROADCAST: 509 case INADDR_ANY: 510 icmpdst.sin_addr = ip->ip_src; 511 break; 512 513 default: 514 icmpdst.sin_addr = ip->ip_dst; 515 } 516 ia = (struct in_ifaddr *)ifaof_ifpforaddr( 517 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif); 518 if (ia == 0) 519 break; 520 if (ia->ia_ifp == 0) 521 break; 522 icp->icmp_type = ICMP_MASKREPLY; 523 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; 524 if (ip->ip_src.s_addr == 0) { 525 if (ia->ia_ifp->if_flags & IFF_BROADCAST) 526 ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr; 527 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) 528 ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr; 529 } 530 reflect: 531 ip->ip_len += hlen; /* since ip_input deducts this */ 532 icmpstat.icps_reflect++; 533 icmpstat.icps_outhist[icp->icmp_type]++; 534 icmp_reflect(m); 535 return; 536 537 case ICMP_REDIRECT: 538 if (log_redirect) { 539 u_long src, dst, gw; 540 541 src = ntohl(ip->ip_src.s_addr); 542 dst = ntohl(icp->icmp_ip.ip_dst.s_addr); 543 gw = ntohl(icp->icmp_gwaddr.s_addr); 544 printf("icmp redirect from %d.%d.%d.%d: " 545 "%d.%d.%d.%d => %d.%d.%d.%d\n", 546 (int)(src >> 24), (int)((src >> 16) & 0xff), 547 (int)((src >> 8) & 0xff), (int)(src & 0xff), 548 (int)(dst >> 24), (int)((dst >> 16) & 0xff), 549 (int)((dst >> 8) & 0xff), (int)(dst & 0xff), 550 (int)(gw >> 24), (int)((gw >> 16) & 0xff), 551 (int)((gw >> 8) & 0xff), (int)(gw & 0xff)); 552 } 553 if (drop_redirect) 554 break; 555 if (code > 3) 556 goto badcode; 557 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 558 IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) { 559 icmpstat.icps_badlen++; 560 break; 561 } 562 /* 563 * Short circuit routing redirects to force 564 * immediate change in the kernel's routing 565 * tables. The message is also handed to anyone 566 * listening on a raw socket (e.g. the routing 567 * daemon for use in updating its tables). 568 */ 569 icmpgw.sin_addr = ip->ip_src; 570 icmpdst.sin_addr = icp->icmp_gwaddr; 571 #ifdef ICMPPRINTFS 572 if (icmpprintfs) { 573 char buf[sizeof "aaa.bbb.ccc.ddd"]; 574 575 strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst)); 576 printf("redirect dst %s to %s\n", 577 buf, inet_ntoa(icp->icmp_gwaddr)); 578 } 579 #endif 580 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 581 rtredirect((struct sockaddr *)&icmpsrc, 582 (struct sockaddr *)&icmpdst, 583 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST, 584 (struct sockaddr *)&icmpgw, (struct rtentry **)0); 585 pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc); 586 #ifdef IPSEC 587 key_sa_routechange((struct sockaddr *)&icmpsrc); 588 #endif 589 break; 590 591 /* 592 * No kernel processing for the following; 593 * just fall through to send to raw listener. 594 */ 595 case ICMP_ECHOREPLY: 596 case ICMP_ROUTERADVERT: 597 case ICMP_ROUTERSOLICIT: 598 case ICMP_TSTAMPREPLY: 599 case ICMP_IREQREPLY: 600 case ICMP_MASKREPLY: 601 default: 602 break; 603 } 604 605 raw: 606 rip_input(m, off, proto); 607 return; 608 609 freeit: 610 m_freem(m); 611 } 612 613 /* 614 * Reflect the ip packet back to the source 615 */ 616 static void 617 icmp_reflect(m) 618 struct mbuf *m; 619 { 620 struct ip *ip = mtod(m, struct ip *); 621 struct ifaddr *ifa; 622 struct in_ifaddr *ia; 623 struct in_addr t; 624 struct mbuf *opts = 0; 625 int optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 626 struct route *ro = NULL, rt; 627 628 if (!in_canforward(ip->ip_src) && 629 ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) != 630 (IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) { 631 m_freem(m); /* Bad return address */ 632 icmpstat.icps_badaddr++; 633 goto done; /* Ip_output() will check for broadcast */ 634 } 635 t = ip->ip_dst; 636 ip->ip_dst = ip->ip_src; 637 ro = &rt; 638 bzero(ro, sizeof *ro); 639 /* 640 * If the incoming packet was addressed directly to us, 641 * use dst as the src for the reply. Otherwise (broadcast 642 * or anonymous), use the address which corresponds 643 * to the incoming interface. 644 */ 645 LIST_FOREACH(ia, INADDR_HASH(t.s_addr), ia_hash) 646 if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr) 647 goto match; 648 if (m->m_pkthdr.rcvif != NULL && 649 m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 650 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 651 if (ifa->ifa_addr->sa_family != AF_INET) 652 continue; 653 ia = ifatoia(ifa); 654 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 655 t.s_addr) 656 goto match; 657 } 658 } 659 ia = ip_rtaddr(ip->ip_dst, ro); 660 /* We need a route to do anything useful. */ 661 if (ia == NULL) { 662 m_freem(m); 663 icmpstat.icps_noroute++; 664 goto done; 665 } 666 match: 667 t = IA_SIN(ia)->sin_addr; 668 ip->ip_src = t; 669 ip->ip_ttl = ip_defttl; 670 671 if (optlen > 0) { 672 u_char *cp; 673 int opt, cnt; 674 u_int len; 675 676 /* 677 * Retrieve any source routing from the incoming packet; 678 * add on any record-route or timestamp options. 679 */ 680 cp = (u_char *) (ip + 1); 681 if ((opts = ip_srcroute()) == 0 && 682 (opts = m_gethdr(MB_DONTWAIT, MT_HEADER))) { 683 opts->m_len = sizeof(struct in_addr); 684 mtod(opts, struct in_addr *)->s_addr = 0; 685 } 686 if (opts) { 687 #ifdef ICMPPRINTFS 688 if (icmpprintfs) 689 printf("icmp_reflect optlen %d rt %d => ", 690 optlen, opts->m_len); 691 #endif 692 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { 693 opt = cp[IPOPT_OPTVAL]; 694 if (opt == IPOPT_EOL) 695 break; 696 if (opt == IPOPT_NOP) 697 len = 1; 698 else { 699 if (cnt < IPOPT_OLEN + sizeof *cp) 700 break; 701 len = cp[IPOPT_OLEN]; 702 if (len < IPOPT_OLEN + sizeof *cp || 703 len > cnt) 704 break; 705 } 706 /* 707 * Should check for overflow, but it 708 * "can't happen". 709 */ 710 if (opt == IPOPT_RR || opt == IPOPT_TS || 711 opt == IPOPT_SECURITY) { 712 bcopy(cp, 713 mtod(opts, caddr_t) + opts->m_len, 714 len); 715 opts->m_len += len; 716 } 717 } 718 /* Terminate & pad, if necessary */ 719 cnt = opts->m_len % 4; 720 if (cnt) { 721 for (; cnt < 4; cnt++) { 722 *(mtod(opts, caddr_t) + opts->m_len) = 723 IPOPT_EOL; 724 opts->m_len++; 725 } 726 } 727 #ifdef ICMPPRINTFS 728 if (icmpprintfs) 729 printf("%d\n", opts->m_len); 730 #endif 731 } 732 /* 733 * Now strip out original options by copying rest of first 734 * mbuf's data back, and adjust the IP length. 735 */ 736 ip->ip_len -= optlen; 737 ip->ip_vhl = IP_VHL_BORING; 738 m->m_len -= optlen; 739 if (m->m_flags & M_PKTHDR) 740 m->m_pkthdr.len -= optlen; 741 optlen += sizeof(struct ip); 742 bcopy((caddr_t)ip + optlen, ip + 1, 743 m->m_len - sizeof(struct ip)); 744 } 745 m->m_pkthdr.pf_flags &= PF_MBUF_GENERATED; 746 m->m_flags &= ~(M_BCAST|M_MCAST); 747 icmp_send(m, opts, ro); 748 done: 749 if (opts) 750 m_free(opts); 751 if (ro && ro->ro_rt) 752 RTFREE(ro->ro_rt); 753 } 754 755 /* 756 * Send an icmp packet back to the ip level, 757 * after supplying a checksum. 758 */ 759 static void 760 icmp_send(m, opts, rt) 761 struct mbuf *m; 762 struct mbuf *opts; 763 struct route *rt; 764 { 765 struct ip *ip = mtod(m, struct ip *); 766 int hlen; 767 struct icmp *icp; 768 769 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 770 m->m_data += hlen; 771 m->m_len -= hlen; 772 icp = mtod(m, struct icmp *); 773 icp->icmp_cksum = 0; 774 icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen); 775 m->m_data -= hlen; 776 m->m_len += hlen; 777 m->m_pkthdr.rcvif = (struct ifnet *)0; 778 #ifdef ICMPPRINTFS 779 if (icmpprintfs) { 780 char buf[sizeof "aaa.bbb.ccc.ddd"]; 781 782 strcpy(buf, inet_ntoa(ip->ip_dst)); 783 printf("icmp_send dst %s src %s\n", buf, inet_ntoa(ip->ip_src)); 784 } 785 #endif 786 ip_output(m, opts, rt, 0, NULL, NULL); 787 } 788 789 n_time 790 iptime() 791 { 792 struct timeval atv; 793 u_long t; 794 795 getmicrotime(&atv); 796 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; 797 return (htonl(t)); 798 } 799 800 #if 1 801 /* 802 * Return the next larger or smaller MTU plateau (table from RFC 1191) 803 * given current value MTU. If DIR is less than zero, a larger plateau 804 * is returned; otherwise, a smaller value is returned. 805 */ 806 static int 807 ip_next_mtu(mtu, dir) 808 int mtu; 809 int dir; 810 { 811 static int mtutab[] = { 812 65535, 32000, 17914, 8166, 4352, 2002, 1492, 1006, 508, 296, 813 68, 0 814 }; 815 int i; 816 817 for (i = 0; i < (sizeof mtutab) / (sizeof mtutab[0]); i++) { 818 if (mtu >= mtutab[i]) 819 break; 820 } 821 822 if (dir < 0) { 823 if (i == 0) { 824 return 0; 825 } else { 826 return mtutab[i - 1]; 827 } 828 } else { 829 if (mtutab[i] == 0) { 830 return 0; 831 } else if(mtu > mtutab[i]) { 832 return mtutab[i]; 833 } else { 834 return mtutab[i + 1]; 835 } 836 } 837 } 838 #endif 839 840 #ifdef ICMP_BANDLIM 841 /* 842 * badport_bandlim() - check for ICMP bandwidth limit 843 * 844 * Return 0 if it is ok to send an ICMP error response, -1 if we have 845 * hit our bandwidth limit and it is not ok. 846 * 847 * If icmplim is <= 0, the feature is disabled and 0 is returned. 848 * 849 * For now we separate the TCP and UDP subsystems w/ different 'which' 850 * values. We may eventually remove this separation (and simplify the 851 * code further). 852 * 853 * Note that the printing of the error message is delayed so we can 854 * properly print the icmp error rate that the system was trying to do 855 * (i.e. 22000/100 pps, etc...). This can cause long delays in printing 856 * the 'final' error, but it doesn't make sense to solve the printing 857 * delay with more complex code. 858 */ 859 int 860 badport_bandlim(int which) 861 { 862 static int lticks[BANDLIM_MAX + 1]; 863 static int lpackets[BANDLIM_MAX + 1]; 864 int dticks; 865 const char *bandlimittype[] = { 866 "Limiting icmp unreach response", 867 "Limiting icmp ping response", 868 "Limiting icmp tstamp response", 869 "Limiting closed port RST response", 870 "Limiting open port RST response" 871 }; 872 873 /* 874 * Return ok status if feature disabled or argument out of 875 * ranage. 876 */ 877 878 if (icmplim <= 0 || which > BANDLIM_MAX || which < 0) 879 return(0); 880 dticks = ticks - lticks[which]; 881 882 /* 883 * reset stats when cumulative dt exceeds one second. 884 */ 885 886 if ((unsigned int)dticks > hz) { 887 if (lpackets[which] > icmplim && icmplim_output) { 888 printf("%s from %d to %d packets per second\n", 889 bandlimittype[which], 890 lpackets[which], 891 icmplim 892 ); 893 } 894 lticks[which] = ticks; 895 lpackets[which] = 0; 896 } 897 898 /* 899 * bump packet count 900 */ 901 902 if (++lpackets[which] > icmplim) { 903 return(-1); 904 } 905 return(0); 906 } 907 #endif 908