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 1.32 2008/10/27 02:56:30 sephe 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/socketops.h> 46 #include <sys/time.h> 47 #include <sys/kernel.h> 48 #include <sys/sysctl.h> 49 #include <sys/in_cksum.h> 50 51 #include <machine/stdarg.h> 52 53 #include <net/if.h> 54 #include <net/if_types.h> 55 #include <net/route.h> 56 57 #define _IP_VHL 58 #include <netinet/in.h> 59 #include <netinet/in_systm.h> 60 #include <netinet/in_var.h> 61 #include <netinet/ip.h> 62 #include <netinet/ip_icmp.h> 63 #include <netinet/ip_var.h> 64 #include <netinet/icmp_var.h> 65 66 #ifdef IPSEC 67 #include <netinet6/ipsec.h> 68 #include <netproto/key/key.h> 69 #endif 70 71 #ifdef FAST_IPSEC 72 #include <netproto/ipsec/ipsec.h> 73 #include <netproto/ipsec/key.h> 74 #define IPSEC 75 #endif 76 77 /* 78 * ICMP routines: error generation, receive packet processing, and 79 * routines to turnaround packets back to the originator, and 80 * host table maintenance routines. 81 */ 82 83 struct icmpstat icmpstat; 84 SYSCTL_STRUCT(_net_inet_icmp, ICMPCTL_STATS, stats, CTLFLAG_RW, 85 &icmpstat, icmpstat, ""); 86 87 static int icmpmaskrepl = 0; 88 SYSCTL_INT(_net_inet_icmp, ICMPCTL_MASKREPL, maskrepl, CTLFLAG_RW, 89 &icmpmaskrepl, 0, ""); 90 91 static int drop_redirect = 0; 92 SYSCTL_INT(_net_inet_icmp, OID_AUTO, drop_redirect, CTLFLAG_RW, 93 &drop_redirect, 0, ""); 94 95 static int log_redirect = 0; 96 SYSCTL_INT(_net_inet_icmp, OID_AUTO, log_redirect, CTLFLAG_RW, 97 &log_redirect, 0, ""); 98 99 #ifdef ICMP_BANDLIM 100 101 /* 102 * ICMP error-response bandwidth limiting sysctl. If not enabled, sysctl 103 * variable content is -1 and read-only. 104 */ 105 106 static int icmplim = 200; 107 SYSCTL_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_RW, 108 &icmplim, 0, ""); 109 #else 110 111 static int icmplim = -1; 112 SYSCTL_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_RD, 113 &icmplim, 0, ""); 114 115 #endif 116 117 static int icmplim_output = 1; 118 SYSCTL_INT(_net_inet_icmp, OID_AUTO, icmplim_output, CTLFLAG_RW, 119 &icmplim_output, 0, ""); 120 121 /* 122 * ICMP broadcast echo sysctl 123 */ 124 125 static int icmpbmcastecho = 0; 126 SYSCTL_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_RW, 127 &icmpbmcastecho, 0, ""); 128 129 130 #ifdef ICMPPRINTFS 131 int icmpprintfs = 0; 132 #endif 133 134 static void icmp_reflect (struct mbuf *); 135 static void icmp_send (struct mbuf *, struct mbuf *, struct route *); 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(struct mbuf *n, int type, int code, n_long dest, int destmtu) 145 { 146 struct ip *oip = mtod(n, struct ip *), *nip; 147 unsigned oiplen = IP_VHL_HL(oip->ip_vhl) << 2; 148 struct icmp *icp; 149 struct mbuf *m; 150 unsigned icmplen; 151 152 #ifdef ICMPPRINTFS 153 if (icmpprintfs) 154 kprintf("icmp_error(%p, %d, %d)\n", oip, type, code); 155 #endif 156 if (type != ICMP_REDIRECT) 157 icmpstat.icps_error++; 158 /* 159 * Don't send error if the original packet was encrypted. 160 * Don't send error if not the first fragment of message. 161 * Don't error if the old packet protocol was ICMP 162 * error message, only known informational types. 163 */ 164 if (n->m_flags & M_DECRYPTED) 165 goto freeit; 166 if (oip->ip_off &~ (IP_MF|IP_DF)) 167 goto freeit; 168 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && 169 n->m_len >= oiplen + ICMP_MINLEN && 170 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiplen))->icmp_type)) { 171 icmpstat.icps_oldicmp++; 172 goto freeit; 173 } 174 /* Don't send error in response to a multicast or broadcast packet */ 175 if (n->m_flags & (M_BCAST|M_MCAST)) 176 goto freeit; 177 /* 178 * First, formulate icmp message 179 */ 180 m = m_gethdr(MB_DONTWAIT, MT_HEADER); 181 if (m == NULL) 182 goto freeit; 183 icmplen = min(oiplen + 8, oip->ip_len); 184 if (icmplen < sizeof(struct ip)) 185 panic("icmp_error: bad length"); 186 m->m_len = icmplen + ICMP_MINLEN; 187 MH_ALIGN(m, m->m_len); 188 icp = mtod(m, struct icmp *); 189 if ((u_int)type > ICMP_MAXTYPE) 190 panic("icmp_error"); 191 icmpstat.icps_outhist[type]++; 192 icp->icmp_type = type; 193 if (type == ICMP_REDIRECT) 194 icp->icmp_gwaddr.s_addr = dest; 195 else { 196 icp->icmp_void = 0; 197 /* 198 * The following assignments assume an overlay with the 199 * zeroed icmp_void field. 200 */ 201 if (type == ICMP_PARAMPROB) { 202 icp->icmp_pptr = code; 203 code = 0; 204 } else if (type == ICMP_UNREACH && 205 code == ICMP_UNREACH_NEEDFRAG && destmtu) { 206 icp->icmp_nextmtu = htons(destmtu); 207 } 208 } 209 210 icp->icmp_code = code; 211 m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip); 212 nip = &icp->icmp_ip; 213 214 /* 215 * Convert fields to network representation. 216 */ 217 nip->ip_len = htons(nip->ip_len); 218 nip->ip_off = htons(nip->ip_off); 219 220 /* 221 * Now, copy old ip header (without options) 222 * in front of icmp message. 223 */ 224 if (m->m_data - sizeof(struct ip) < m->m_pktdat) 225 panic("icmp len"); 226 m->m_data -= sizeof(struct ip); 227 m->m_len += sizeof(struct ip); 228 m->m_pkthdr.len = m->m_len; 229 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif; 230 nip = mtod(m, struct ip *); 231 bcopy(oip, nip, sizeof(struct ip)); 232 nip->ip_len = m->m_len; 233 nip->ip_vhl = IP_VHL_BORING; 234 nip->ip_p = IPPROTO_ICMP; 235 nip->ip_tos = 0; 236 m->m_pkthdr.fw_flags |= n->m_pkthdr.fw_flags & FW_MBUF_GENERATED; 237 icmp_reflect(m); 238 239 freeit: 240 m_freem(n); 241 } 242 243 /* 244 * Process a received ICMP message. 245 */ 246 void 247 icmp_input(struct mbuf *m, ...) 248 { 249 struct sockaddr_in icmpsrc = { sizeof(struct sockaddr_in), AF_INET }; 250 struct sockaddr_in icmpdst = { sizeof(struct sockaddr_in), AF_INET }; 251 struct sockaddr_in icmpgw = { sizeof(struct sockaddr_in), AF_INET }; 252 struct icmp *icp; 253 struct in_ifaddr *ia; 254 struct ip *ip = mtod(m, struct ip *); 255 int icmplen = ip->ip_len; 256 int i, hlen; 257 int code, off, proto; 258 __va_list ap; 259 260 __va_start(ap, m); 261 off = __va_arg(ap, int); 262 proto = __va_arg(ap, int); 263 __va_end(ap); 264 265 hlen = off; 266 267 /* 268 * Locate icmp structure in mbuf, and check 269 * that not corrupted and of at least minimum length. 270 */ 271 #ifdef ICMPPRINTFS 272 if (icmpprintfs) { 273 char buf[sizeof "aaa.bbb.ccc.ddd"]; 274 275 strcpy(buf, inet_ntoa(ip->ip_src)); 276 kprintf("icmp_input from %s to %s, len %d\n", 277 buf, inet_ntoa(ip->ip_dst), icmplen); 278 } 279 #endif 280 if (icmplen < ICMP_MINLEN) { 281 icmpstat.icps_tooshort++; 282 goto freeit; 283 } 284 i = hlen + min(icmplen, ICMP_ADVLENMIN); 285 if (m->m_len < i && (m = m_pullup(m, i)) == 0) { 286 icmpstat.icps_tooshort++; 287 return; 288 } 289 ip = mtod(m, struct ip *); 290 m->m_len -= hlen; 291 m->m_data += hlen; 292 icp = mtod(m, struct icmp *); 293 if (in_cksum(m, icmplen)) { 294 icmpstat.icps_checksum++; 295 goto freeit; 296 } 297 m->m_len += hlen; 298 m->m_data -= hlen; 299 300 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 301 /* 302 * Deliver very specific ICMP type only. 303 */ 304 switch (icp->icmp_type) { 305 case ICMP_UNREACH: 306 case ICMP_TIMXCEED: 307 break; 308 default: 309 goto freeit; 310 } 311 } 312 313 #ifdef ICMPPRINTFS 314 if (icmpprintfs) 315 kprintf("icmp_input, type %d code %d\n", icp->icmp_type, 316 icp->icmp_code); 317 #endif 318 319 /* 320 * Message type specific processing. 321 */ 322 if (icp->icmp_type > ICMP_MAXTYPE) 323 goto raw; 324 icmpstat.icps_inhist[icp->icmp_type]++; 325 code = icp->icmp_code; 326 switch (icp->icmp_type) { 327 328 case ICMP_UNREACH: 329 switch (code) { 330 case ICMP_UNREACH_NET: 331 case ICMP_UNREACH_HOST: 332 case ICMP_UNREACH_SRCFAIL: 333 case ICMP_UNREACH_NET_UNKNOWN: 334 case ICMP_UNREACH_HOST_UNKNOWN: 335 case ICMP_UNREACH_ISOLATED: 336 case ICMP_UNREACH_TOSNET: 337 case ICMP_UNREACH_TOSHOST: 338 case ICMP_UNREACH_HOST_PRECEDENCE: 339 case ICMP_UNREACH_PRECEDENCE_CUTOFF: 340 code = PRC_UNREACH_NET; 341 break; 342 343 case ICMP_UNREACH_NEEDFRAG: 344 code = PRC_MSGSIZE; 345 break; 346 347 /* 348 * RFC 1122, Sections 3.2.2.1 and 4.2.3.9. 349 * Treat subcodes 2,3 as immediate RST 350 */ 351 case ICMP_UNREACH_PROTOCOL: 352 case ICMP_UNREACH_PORT: 353 code = PRC_UNREACH_PORT; 354 break; 355 356 case ICMP_UNREACH_NET_PROHIB: 357 case ICMP_UNREACH_HOST_PROHIB: 358 case ICMP_UNREACH_FILTER_PROHIB: 359 code = PRC_UNREACH_ADMIN_PROHIB; 360 break; 361 362 default: 363 goto badcode; 364 } 365 goto deliver; 366 367 case ICMP_TIMXCEED: 368 if (code > 1) 369 goto badcode; 370 code += PRC_TIMXCEED_INTRANS; 371 goto deliver; 372 373 case ICMP_PARAMPROB: 374 if (code > 1) 375 goto badcode; 376 code = PRC_PARAMPROB; 377 goto deliver; 378 379 case ICMP_SOURCEQUENCH: 380 if (code) 381 goto badcode; 382 code = PRC_QUENCH; 383 deliver: 384 /* 385 * Problem with datagram; advise higher level routines. 386 */ 387 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 388 IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) { 389 icmpstat.icps_badlen++; 390 goto freeit; 391 } 392 icp->icmp_ip.ip_len = ntohs(icp->icmp_ip.ip_len); 393 /* Discard ICMP's in response to multicast packets */ 394 if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr))) 395 goto badcode; 396 #ifdef ICMPPRINTFS 397 if (icmpprintfs) 398 kprintf("deliver to protocol %d\n", icp->icmp_ip.ip_p); 399 #endif 400 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 401 #if 1 402 /* 403 * MTU discovery: 404 * If we got a needfrag and there is a host route to the 405 * original destination, and the MTU is not locked, then 406 * set the MTU in the route to the suggested new value 407 * (if given) and then notify as usual. The ULPs will 408 * notice that the MTU has changed and adapt accordingly. 409 * If no new MTU was suggested, then we guess a new one 410 * less than the current value. If the new MTU is 411 * unreasonably small (arbitrarily set at 296), then 412 * we reset the MTU to the interface value and enable the 413 * lock bit, indicating that we are no longer doing MTU 414 * discovery. 415 */ 416 if (code == PRC_MSGSIZE) { 417 struct rtentry *rt; 418 int mtu; 419 420 rt = rtpurelookup((struct sockaddr *)&icmpsrc); 421 if (rt != NULL && (rt->rt_flags & RTF_HOST) && 422 !(rt->rt_rmx.rmx_locks & RTV_MTU)) { 423 mtu = ntohs(icp->icmp_nextmtu); 424 if (!mtu) 425 mtu = ip_next_mtu(rt->rt_rmx.rmx_mtu, 426 1); 427 #ifdef DEBUG_MTUDISC 428 kprintf("MTU for %s reduced to %d\n", 429 inet_ntoa(icmpsrc.sin_addr), mtu); 430 #endif 431 if (mtu < 296) { 432 /* rt->rt_rmx.rmx_mtu = 433 rt->rt_ifp->if_mtu; */ 434 rt->rt_rmx.rmx_locks |= RTV_MTU; 435 } else if (rt->rt_rmx.rmx_mtu > mtu) { 436 rt->rt_rmx.rmx_mtu = mtu; 437 } 438 } 439 if (rt != NULL) 440 --rt->rt_refcnt; 441 } 442 #endif 443 /* 444 * XXX if the packet contains [IPv4 AH TCP], we can't make a 445 * notification to TCP layer. 446 */ 447 so_pru_ctlinput( 448 &inetsw[ip_protox[icp->icmp_ip.ip_p]], 449 code, (struct sockaddr *)&icmpsrc, &icp->icmp_ip); 450 break; 451 452 badcode: 453 icmpstat.icps_badcode++; 454 break; 455 456 case ICMP_ECHO: 457 if (!icmpbmcastecho 458 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) { 459 icmpstat.icps_bmcastecho++; 460 break; 461 } 462 icp->icmp_type = ICMP_ECHOREPLY; 463 #ifdef ICMP_BANDLIM 464 if (badport_bandlim(BANDLIM_ICMP_ECHO) < 0) 465 goto freeit; 466 else 467 #endif 468 goto reflect; 469 470 case ICMP_TSTAMP: 471 if (!icmpbmcastecho 472 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) { 473 icmpstat.icps_bmcasttstamp++; 474 break; 475 } 476 if (icmplen < ICMP_TSLEN) { 477 icmpstat.icps_badlen++; 478 break; 479 } 480 icp->icmp_type = ICMP_TSTAMPREPLY; 481 icp->icmp_rtime = iptime(); 482 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ 483 #ifdef ICMP_BANDLIM 484 if (badport_bandlim(BANDLIM_ICMP_TSTAMP) < 0) 485 goto freeit; 486 else 487 #endif 488 goto reflect; 489 490 case ICMP_MASKREQ: 491 if (icmpmaskrepl == 0) 492 break; 493 /* 494 * We are not able to respond with all ones broadcast 495 * unless we receive it over a point-to-point interface. 496 */ 497 if (icmplen < ICMP_MASKLEN) 498 break; 499 switch (ip->ip_dst.s_addr) { 500 501 case INADDR_BROADCAST: 502 case INADDR_ANY: 503 icmpdst.sin_addr = ip->ip_src; 504 break; 505 506 default: 507 icmpdst.sin_addr = ip->ip_dst; 508 } 509 ia = (struct in_ifaddr *)ifaof_ifpforaddr( 510 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif); 511 if (ia == 0) 512 break; 513 if (ia->ia_ifp == 0) 514 break; 515 icp->icmp_type = ICMP_MASKREPLY; 516 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; 517 if (ip->ip_src.s_addr == 0) { 518 if (ia->ia_ifp->if_flags & IFF_BROADCAST) 519 ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr; 520 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) 521 ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr; 522 } 523 reflect: 524 ip->ip_len += hlen; /* since ip_input deducts this */ 525 icmpstat.icps_reflect++; 526 icmpstat.icps_outhist[icp->icmp_type]++; 527 icmp_reflect(m); 528 return; 529 530 case ICMP_REDIRECT: 531 if (log_redirect) { 532 u_long src, dst, gw; 533 534 src = ntohl(ip->ip_src.s_addr); 535 dst = ntohl(icp->icmp_ip.ip_dst.s_addr); 536 gw = ntohl(icp->icmp_gwaddr.s_addr); 537 kprintf("icmp redirect from %d.%d.%d.%d: " 538 "%d.%d.%d.%d => %d.%d.%d.%d\n", 539 (int)(src >> 24), (int)((src >> 16) & 0xff), 540 (int)((src >> 8) & 0xff), (int)(src & 0xff), 541 (int)(dst >> 24), (int)((dst >> 16) & 0xff), 542 (int)((dst >> 8) & 0xff), (int)(dst & 0xff), 543 (int)(gw >> 24), (int)((gw >> 16) & 0xff), 544 (int)((gw >> 8) & 0xff), (int)(gw & 0xff)); 545 } 546 if (drop_redirect) 547 break; 548 if (code > 3) 549 goto badcode; 550 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 551 IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) { 552 icmpstat.icps_badlen++; 553 break; 554 } 555 /* 556 * Short circuit routing redirects to force 557 * immediate change in the kernel's routing 558 * tables. The message is also handed to anyone 559 * listening on a raw socket (e.g. the routing 560 * daemon for use in updating its tables). 561 */ 562 icmpgw.sin_addr = ip->ip_src; 563 icmpdst.sin_addr = icp->icmp_gwaddr; 564 #ifdef ICMPPRINTFS 565 if (icmpprintfs) { 566 char buf[sizeof "aaa.bbb.ccc.ddd"]; 567 568 strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst)); 569 kprintf("redirect dst %s to %s\n", 570 buf, inet_ntoa(icp->icmp_gwaddr)); 571 } 572 #endif 573 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 574 rtredirect((struct sockaddr *)&icmpsrc, 575 (struct sockaddr *)&icmpdst, 576 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST, 577 (struct sockaddr *)&icmpgw); 578 kpfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc); 579 #ifdef IPSEC 580 key_sa_routechange((struct sockaddr *)&icmpsrc); 581 #endif 582 break; 583 584 /* 585 * No kernel processing for the following; 586 * just fall through to send to raw listener. 587 */ 588 case ICMP_ECHOREPLY: 589 case ICMP_ROUTERADVERT: 590 case ICMP_ROUTERSOLICIT: 591 case ICMP_TSTAMPREPLY: 592 case ICMP_IREQREPLY: 593 case ICMP_MASKREPLY: 594 default: 595 break; 596 } 597 598 raw: 599 rip_input(m, off, proto); 600 return; 601 602 freeit: 603 m_freem(m); 604 } 605 606 /* 607 * Reflect the ip packet back to the source 608 */ 609 static void 610 icmp_reflect(struct mbuf *m) 611 { 612 struct ip *ip = mtod(m, struct ip *); 613 struct in_ifaddr *ia; 614 struct in_ifaddr_container *iac; 615 struct in_addr t; 616 struct mbuf *opts = 0; 617 int optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 618 struct route *ro = NULL, rt; 619 620 if (!in_canforward(ip->ip_src) && 621 ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) != 622 (IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) { 623 m_freem(m); /* Bad return address */ 624 icmpstat.icps_badaddr++; 625 goto done; /* Ip_output() will check for broadcast */ 626 } 627 t = ip->ip_dst; 628 ip->ip_dst = ip->ip_src; 629 ro = &rt; 630 bzero(ro, sizeof *ro); 631 /* 632 * If the incoming packet was addressed directly to us, 633 * use dst as the src for the reply. Otherwise (broadcast 634 * or anonymous), use the address which corresponds 635 * to the incoming interface. 636 */ 637 ia = NULL; 638 LIST_FOREACH(iac, INADDR_HASH(t.s_addr), ia_hash) { 639 if (t.s_addr == IA_SIN(iac->ia)->sin_addr.s_addr) { 640 ia = iac->ia; 641 goto match; 642 } 643 } 644 if (m->m_pkthdr.rcvif != NULL && 645 m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 646 struct ifaddr_container *ifac; 647 648 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid], 649 ifa_link) { 650 struct ifaddr *ifa = ifac->ifa; 651 652 if (ifa->ifa_addr->sa_family != AF_INET) 653 continue; 654 ia = ifatoia(ifa); 655 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 656 t.s_addr) 657 goto match; 658 } 659 } 660 ia = ip_rtaddr(ip->ip_dst, ro); 661 /* We need a route to do anything useful. */ 662 if (ia == NULL) { 663 m_freem(m); 664 icmpstat.icps_noroute++; 665 goto done; 666 } 667 match: 668 t = IA_SIN(ia)->sin_addr; 669 ip->ip_src = t; 670 ip->ip_ttl = ip_defttl; 671 672 if (optlen > 0) { 673 u_char *cp; 674 int opt, cnt; 675 u_int len; 676 677 /* 678 * Retrieve any source routing from the incoming packet; 679 * add on any record-route or timestamp options. 680 */ 681 cp = (u_char *) (ip + 1); 682 if ((opts = ip_srcroute(m)) == 0 && 683 (opts = m_gethdr(MB_DONTWAIT, MT_HEADER))) { 684 opts->m_len = sizeof(struct in_addr); 685 mtod(opts, struct in_addr *)->s_addr = 0; 686 } 687 if (opts) { 688 #ifdef ICMPPRINTFS 689 if (icmpprintfs) 690 kprintf("icmp_reflect optlen %d rt %d => ", 691 optlen, opts->m_len); 692 #endif 693 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { 694 opt = cp[IPOPT_OPTVAL]; 695 if (opt == IPOPT_EOL) 696 break; 697 if (opt == IPOPT_NOP) 698 len = 1; 699 else { 700 if (cnt < IPOPT_OLEN + sizeof *cp) 701 break; 702 len = cp[IPOPT_OLEN]; 703 if (len < IPOPT_OLEN + sizeof *cp || 704 len > cnt) 705 break; 706 } 707 /* 708 * Should check for overflow, but it 709 * "can't happen". 710 */ 711 if (opt == IPOPT_RR || opt == IPOPT_TS || 712 opt == IPOPT_SECURITY) { 713 bcopy(cp, 714 mtod(opts, caddr_t) + opts->m_len, 715 len); 716 opts->m_len += len; 717 } 718 } 719 /* Terminate & pad, if necessary */ 720 cnt = opts->m_len % 4; 721 if (cnt) { 722 for (; cnt < 4; cnt++) { 723 *(mtod(opts, caddr_t) + opts->m_len) = 724 IPOPT_EOL; 725 opts->m_len++; 726 } 727 } 728 #ifdef ICMPPRINTFS 729 if (icmpprintfs) 730 kprintf("%d\n", opts->m_len); 731 #endif 732 } 733 /* 734 * Now strip out original options by copying rest of first 735 * mbuf's data back, and adjust the IP length. 736 */ 737 ip->ip_len -= optlen; 738 ip->ip_vhl = IP_VHL_BORING; 739 m->m_len -= optlen; 740 if (m->m_flags & M_PKTHDR) 741 m->m_pkthdr.len -= optlen; 742 optlen += sizeof(struct ip); 743 bcopy((caddr_t)ip + optlen, ip + 1, 744 m->m_len - sizeof(struct ip)); 745 } 746 m->m_pkthdr.fw_flags &= FW_MBUF_GENERATED; 747 m->m_flags &= ~(M_BCAST|M_MCAST); 748 icmp_send(m, opts, ro); 749 done: 750 if (opts) 751 m_free(opts); 752 if (ro && ro->ro_rt) 753 RTFREE(ro->ro_rt); 754 } 755 756 /* 757 * Send an icmp packet back to the ip level, 758 * after supplying a checksum. 759 */ 760 static void 761 icmp_send(struct mbuf *m, struct mbuf *opts, 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 kprintf("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(void) 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 kprintf("%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