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 * $FreeBSD$ 35 */ 36 37 #include "opt_ipsec.h" 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/mbuf.h> 42 #include <sys/protosw.h> 43 #include <sys/socket.h> 44 #include <sys/time.h> 45 #include <sys/kernel.h> 46 #include <sys/sysctl.h> 47 48 #include <net/if.h> 49 #include <net/route.h> 50 51 #define _IP_VHL 52 #include <netinet/in.h> 53 #include <netinet/in_systm.h> 54 #include <netinet/in_var.h> 55 #include <netinet/ip.h> 56 #include <netinet/ip_icmp.h> 57 #include <netinet/ip_var.h> 58 #include <netinet/icmp_var.h> 59 60 #ifdef IPSEC 61 #include <netinet6/ipsec.h> 62 #include <netkey/key.h> 63 #endif 64 65 #include "faith.h" 66 #if defined(NFAITH) && NFAITH > 0 67 #include <net/if_types.h> 68 #endif 69 70 #include <machine/in_cksum.h> 71 72 /* 73 * ICMP routines: error generation, receive packet processing, and 74 * routines to turnaround packets back to the originator, and 75 * host table maintenance routines. 76 */ 77 78 static struct icmpstat icmpstat; 79 SYSCTL_STRUCT(_net_inet_icmp, ICMPCTL_STATS, stats, CTLFLAG_RD, 80 &icmpstat, icmpstat, ""); 81 82 static int icmpmaskrepl = 0; 83 SYSCTL_INT(_net_inet_icmp, ICMPCTL_MASKREPL, maskrepl, CTLFLAG_RW, 84 &icmpmaskrepl, 0, ""); 85 86 static int drop_redirect = 0; 87 SYSCTL_INT(_net_inet_icmp, OID_AUTO, drop_redirect, CTLFLAG_RW, 88 &drop_redirect, 0, ""); 89 90 static int log_redirect = 0; 91 SYSCTL_INT(_net_inet_icmp, OID_AUTO, log_redirect, CTLFLAG_RW, 92 &log_redirect, 0, ""); 93 94 static int icmplim = 200; 95 SYSCTL_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_RW, 96 &icmplim, 0, ""); 97 98 static int icmplim_output = 1; 99 SYSCTL_INT(_net_inet_icmp, OID_AUTO, icmplim_output, CTLFLAG_RW, 100 &icmplim_output, 0, ""); 101 102 /* 103 * ICMP broadcast echo sysctl 104 */ 105 106 static int icmpbmcastecho = 0; 107 SYSCTL_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_RW, 108 &icmpbmcastecho, 0, ""); 109 110 111 #ifdef ICMPPRINTFS 112 int icmpprintfs = 0; 113 #endif 114 115 static void icmp_reflect __P((struct mbuf *)); 116 static void icmp_send __P((struct mbuf *, struct mbuf *)); 117 static int ip_next_mtu __P((int, int)); 118 119 extern struct protosw inetsw[]; 120 121 /* 122 * Generate an error packet of type error 123 * in response to bad packet ip. 124 */ 125 void 126 icmp_error(n, type, code, dest, destifp) 127 struct mbuf *n; 128 int type, code; 129 n_long dest; 130 struct ifnet *destifp; 131 { 132 register struct ip *oip = mtod(n, struct ip *), *nip; 133 register unsigned oiplen = IP_VHL_HL(oip->ip_vhl) << 2; 134 register struct icmp *icp; 135 register struct mbuf *m; 136 unsigned icmplen; 137 138 #ifdef ICMPPRINTFS 139 if (icmpprintfs) 140 printf("icmp_error(%p, %x, %d)\n", oip, type, code); 141 #endif 142 if (type != ICMP_REDIRECT) 143 icmpstat.icps_error++; 144 /* 145 * Don't send error if not the first fragment of message. 146 * Don't error if the old packet protocol was ICMP 147 * error message, only known informational types. 148 */ 149 if (oip->ip_off &~ (IP_MF|IP_DF)) 150 goto freeit; 151 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && 152 n->m_len >= oiplen + ICMP_MINLEN && 153 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiplen))->icmp_type)) { 154 icmpstat.icps_oldicmp++; 155 goto freeit; 156 } 157 /* Don't send error in response to a multicast or broadcast packet */ 158 if (n->m_flags & (M_BCAST|M_MCAST)) 159 goto freeit; 160 /* 161 * First, formulate icmp message 162 */ 163 m = m_gethdr(M_DONTWAIT, MT_HEADER); 164 if (m == NULL) 165 goto freeit; 166 icmplen = min(oiplen + 8, oip->ip_len); 167 m->m_len = icmplen + ICMP_MINLEN; 168 MH_ALIGN(m, m->m_len); 169 icp = mtod(m, struct icmp *); 170 if ((u_int)type > ICMP_MAXTYPE) 171 panic("icmp_error"); 172 icmpstat.icps_outhist[type]++; 173 icp->icmp_type = type; 174 if (type == ICMP_REDIRECT) 175 icp->icmp_gwaddr.s_addr = dest; 176 else { 177 icp->icmp_void = 0; 178 /* 179 * The following assignments assume an overlay with the 180 * zeroed icmp_void field. 181 */ 182 if (type == ICMP_PARAMPROB) { 183 icp->icmp_pptr = code; 184 code = 0; 185 } else if (type == ICMP_UNREACH && 186 code == ICMP_UNREACH_NEEDFRAG && destifp) { 187 icp->icmp_nextmtu = htons(destifp->if_mtu); 188 } 189 } 190 191 icp->icmp_code = code; 192 bcopy((caddr_t)oip, (caddr_t)&icp->icmp_ip, icmplen); 193 nip = &icp->icmp_ip; 194 195 /* 196 * Convert fields to network representation. 197 */ 198 HTONS(nip->ip_len); 199 HTONS(nip->ip_off); 200 201 /* 202 * Now, copy old ip header (without options) 203 * in front of icmp message. 204 */ 205 if (m->m_data - sizeof(struct ip) < m->m_pktdat) 206 panic("icmp len"); 207 m->m_data -= sizeof(struct ip); 208 m->m_len += sizeof(struct ip); 209 m->m_pkthdr.len = m->m_len; 210 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif; 211 nip = mtod(m, struct ip *); 212 bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip)); 213 nip->ip_len = m->m_len; 214 nip->ip_vhl = IP_VHL_BORING; 215 nip->ip_p = IPPROTO_ICMP; 216 nip->ip_tos = 0; 217 icmp_reflect(m); 218 219 freeit: 220 m_freem(n); 221 } 222 223 static struct sockaddr_in icmpsrc = { sizeof (struct sockaddr_in), AF_INET }; 224 static struct sockaddr_in icmpdst = { sizeof (struct sockaddr_in), AF_INET }; 225 static struct sockaddr_in icmpgw = { sizeof (struct sockaddr_in), AF_INET }; 226 227 /* 228 * Process a received ICMP message. 229 */ 230 void 231 icmp_input(m, off, proto) 232 register struct mbuf *m; 233 int off, proto; 234 { 235 int hlen = off; 236 register struct icmp *icp; 237 register struct ip *ip = mtod(m, struct ip *); 238 int icmplen = ip->ip_len; 239 register int i; 240 struct in_ifaddr *ia; 241 void (*ctlfunc) __P((int, struct sockaddr *, void *)); 242 int code; 243 244 /* 245 * Locate icmp structure in mbuf, and check 246 * that not corrupted and of at least minimum length. 247 */ 248 #ifdef ICMPPRINTFS 249 if (icmpprintfs) { 250 char buf[4 * sizeof "123"]; 251 strcpy(buf, inet_ntoa(ip->ip_src)); 252 printf("icmp_input from %s to %s, len %d\n", 253 buf, inet_ntoa(ip->ip_dst), icmplen); 254 } 255 #endif 256 if (icmplen < ICMP_MINLEN) { 257 icmpstat.icps_tooshort++; 258 goto freeit; 259 } 260 i = hlen + min(icmplen, ICMP_ADVLENMIN); 261 if (m->m_len < i && (m = m_pullup(m, i)) == 0) { 262 icmpstat.icps_tooshort++; 263 return; 264 } 265 ip = mtod(m, struct ip *); 266 m->m_len -= hlen; 267 m->m_data += hlen; 268 icp = mtod(m, struct icmp *); 269 if (in_cksum(m, icmplen)) { 270 icmpstat.icps_checksum++; 271 goto freeit; 272 } 273 m->m_len += hlen; 274 m->m_data -= hlen; 275 276 #if defined(NFAITH) && 0 < NFAITH 277 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 278 /* 279 * Deliver very specific ICMP type only. 280 */ 281 switch (icp->icmp_type) { 282 case ICMP_UNREACH: 283 case ICMP_TIMXCEED: 284 break; 285 default: 286 goto freeit; 287 } 288 } 289 #endif 290 291 #ifdef ICMPPRINTFS 292 if (icmpprintfs) 293 printf("icmp_input, type %d code %d\n", icp->icmp_type, 294 icp->icmp_code); 295 #endif 296 297 #ifdef IPSEC 298 /* drop it if it does not match the policy */ 299 /* XXX Is there meaning of check in here ? */ 300 if (ipsec4_in_reject(m, NULL)) { 301 ipsecstat.in_polvio++; 302 goto freeit; 303 } 304 #endif 305 306 /* 307 * Message type specific processing. 308 */ 309 if (icp->icmp_type > ICMP_MAXTYPE) 310 goto raw; 311 icmpstat.icps_inhist[icp->icmp_type]++; 312 code = icp->icmp_code; 313 switch (icp->icmp_type) { 314 315 case ICMP_UNREACH: 316 switch (code) { 317 case ICMP_UNREACH_NET: 318 case ICMP_UNREACH_HOST: 319 case ICMP_UNREACH_PROTOCOL: 320 case ICMP_UNREACH_PORT: 321 case ICMP_UNREACH_SRCFAIL: 322 code += PRC_UNREACH_NET; 323 break; 324 325 case ICMP_UNREACH_NEEDFRAG: 326 code = PRC_MSGSIZE; 327 break; 328 329 case ICMP_UNREACH_NET_UNKNOWN: 330 case ICMP_UNREACH_NET_PROHIB: 331 if (icp->icmp_ip.ip_p == IPPROTO_TCP) { 332 code = PRC_UNREACH_PORT; 333 break; 334 } 335 336 case ICMP_UNREACH_TOSNET: 337 code = PRC_UNREACH_NET; 338 break; 339 340 case ICMP_UNREACH_HOST_UNKNOWN: 341 case ICMP_UNREACH_ISOLATED: 342 case ICMP_UNREACH_HOST_PROHIB: 343 if (icp->icmp_ip.ip_p == IPPROTO_TCP) { 344 code = PRC_UNREACH_PORT; 345 break; 346 } 347 348 case ICMP_UNREACH_TOSHOST: 349 code = PRC_UNREACH_HOST; 350 break; 351 352 case ICMP_UNREACH_FILTER_PROHIB: 353 if (icp->icmp_ip.ip_p == IPPROTO_TCP) { 354 code = PRC_UNREACH_PORT; 355 break; 356 } 357 358 case ICMP_UNREACH_HOST_PRECEDENCE: 359 case ICMP_UNREACH_PRECEDENCE_CUTOFF: 360 code = PRC_UNREACH_PORT; 361 break; 362 363 default: 364 goto badcode; 365 } 366 goto deliver; 367 368 case ICMP_TIMXCEED: 369 if (code > 1) 370 goto badcode; 371 code += PRC_TIMXCEED_INTRANS; 372 goto deliver; 373 374 case ICMP_PARAMPROB: 375 if (code > 1) 376 goto badcode; 377 code = PRC_PARAMPROB; 378 goto deliver; 379 380 case ICMP_SOURCEQUENCH: 381 if (code) 382 goto badcode; 383 code = PRC_QUENCH; 384 deliver: 385 /* 386 * Problem with datagram; advise higher level routines. 387 */ 388 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 389 IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) { 390 icmpstat.icps_badlen++; 391 goto freeit; 392 } 393 NTOHS(icp->icmp_ip.ip_len); 394 /* Discard ICMP's in response to multicast packets */ 395 if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr))) 396 goto badcode; 397 #ifdef ICMPPRINTFS 398 if (icmpprintfs) 399 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p); 400 #endif 401 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 402 #if 1 403 /* 404 * MTU discovery: 405 * If we got a needfrag and there is a host route to the 406 * original destination, and the MTU is not locked, then 407 * set the MTU in the route to the suggested new value 408 * (if given) and then notify as usual. The ULPs will 409 * notice that the MTU has changed and adapt accordingly. 410 * If no new MTU was suggested, then we guess a new one 411 * less than the current value. If the new MTU is 412 * unreasonably small (arbitrarily set at 296), then 413 * we reset the MTU to the interface value and enable the 414 * lock bit, indicating that we are no longer doing MTU 415 * discovery. 416 */ 417 if (code == PRC_MSGSIZE) { 418 struct rtentry *rt; 419 int mtu; 420 421 rt = rtalloc1((struct sockaddr *)&icmpsrc, 0, 422 RTF_CLONING | RTF_PRCLONING); 423 if (rt && (rt->rt_flags & RTF_HOST) 424 && !(rt->rt_rmx.rmx_locks & RTV_MTU)) { 425 mtu = ntohs(icp->icmp_nextmtu); 426 if (!mtu) 427 mtu = ip_next_mtu(rt->rt_rmx.rmx_mtu, 428 1); 429 #ifdef DEBUG_MTUDISC 430 printf("MTU for %s reduced to %d\n", 431 inet_ntoa(icmpsrc.sin_addr), mtu); 432 #endif 433 if (mtu < 296) { 434 /* rt->rt_rmx.rmx_mtu = 435 rt->rt_ifp->if_mtu; */ 436 rt->rt_rmx.rmx_locks |= RTV_MTU; 437 } else if (rt->rt_rmx.rmx_mtu > mtu) { 438 rt->rt_rmx.rmx_mtu = mtu; 439 } 440 } 441 if (rt) 442 RTFREE(rt); 443 } 444 445 #endif 446 /* 447 * XXX if the packet contains [IPv4 AH TCP], we can't make a 448 * notification to TCP layer. 449 */ 450 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput; 451 if (ctlfunc) 452 (*ctlfunc)(code, (struct sockaddr *)&icmpsrc, 453 (void *)&icp->icmp_ip); 454 break; 455 456 badcode: 457 icmpstat.icps_badcode++; 458 break; 459 460 case ICMP_ECHO: 461 if (!icmpbmcastecho 462 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) { 463 icmpstat.icps_bmcastecho++; 464 break; 465 } 466 icp->icmp_type = ICMP_ECHOREPLY; 467 if (badport_bandlim(BANDLIM_ECHO) < 0) 468 goto freeit; 469 else 470 goto reflect; 471 472 case ICMP_TSTAMP: 473 if (!icmpbmcastecho 474 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) { 475 icmpstat.icps_bmcasttstamp++; 476 break; 477 } 478 if (icmplen < ICMP_TSLEN) { 479 icmpstat.icps_badlen++; 480 break; 481 } 482 icp->icmp_type = ICMP_TSTAMPREPLY; 483 icp->icmp_rtime = iptime(); 484 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ 485 if (badport_bandlim(BANDLIM_TSTAMP) < 0) 486 goto freeit; 487 else 488 goto reflect; 489 490 case ICMP_MASKREQ: 491 #define satosin(sa) ((struct sockaddr_in *)(sa)) 492 if (icmpmaskrepl == 0) 493 break; 494 /* 495 * We are not able to respond with all ones broadcast 496 * unless we receive it over a point-to-point interface. 497 */ 498 if (icmplen < ICMP_MASKLEN) 499 break; 500 switch (ip->ip_dst.s_addr) { 501 502 case INADDR_BROADCAST: 503 case INADDR_ANY: 504 icmpdst.sin_addr = ip->ip_src; 505 break; 506 507 default: 508 icmpdst.sin_addr = ip->ip_dst; 509 } 510 ia = (struct in_ifaddr *)ifaof_ifpforaddr( 511 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif); 512 if (ia == 0) 513 break; 514 if (ia->ia_ifp == 0) 515 break; 516 icp->icmp_type = ICMP_MASKREPLY; 517 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; 518 if (ip->ip_src.s_addr == 0) { 519 if (ia->ia_ifp->if_flags & IFF_BROADCAST) 520 ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr; 521 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) 522 ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr; 523 } 524 reflect: 525 ip->ip_len += hlen; /* since ip_input deducts this */ 526 icmpstat.icps_reflect++; 527 icmpstat.icps_outhist[icp->icmp_type]++; 528 icmp_reflect(m); 529 return; 530 531 case ICMP_REDIRECT: 532 if (log_redirect) { 533 u_long src, dst, gw; 534 535 src = ntohl(ip->ip_src.s_addr); 536 dst = ntohl(icp->icmp_ip.ip_dst.s_addr); 537 gw = ntohl(icp->icmp_gwaddr.s_addr); 538 printf("icmp redirect from %d.%d.%d.%d: " 539 "%d.%d.%d.%d => %d.%d.%d.%d\n", 540 (int)(src >> 24), (int)((src >> 16) & 0xff), 541 (int)((src >> 8) & 0xff), (int)(src & 0xff), 542 (int)(dst >> 24), (int)((dst >> 16) & 0xff), 543 (int)((dst >> 8) & 0xff), (int)(dst & 0xff), 544 (int)(gw >> 24), (int)((gw >> 16) & 0xff), 545 (int)((gw >> 8) & 0xff), (int)(gw & 0xff)); 546 } 547 if (drop_redirect) 548 break; 549 if (code > 3) 550 goto badcode; 551 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 552 IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) { 553 icmpstat.icps_badlen++; 554 break; 555 } 556 /* 557 * Short circuit routing redirects to force 558 * immediate change in the kernel's routing 559 * tables. The message is also handed to anyone 560 * listening on a raw socket (e.g. the routing 561 * daemon for use in updating its tables). 562 */ 563 icmpgw.sin_addr = ip->ip_src; 564 icmpdst.sin_addr = icp->icmp_gwaddr; 565 #ifdef ICMPPRINTFS 566 if (icmpprintfs) { 567 char buf[4 * sizeof "123"]; 568 strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst)); 569 570 printf("redirect dst %s to %s\n", 571 buf, inet_ntoa(icp->icmp_gwaddr)); 572 } 573 #endif 574 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 575 rtredirect((struct sockaddr *)&icmpsrc, 576 (struct sockaddr *)&icmpdst, 577 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST, 578 (struct sockaddr *)&icmpgw, (struct rtentry **)0); 579 pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc); 580 #ifdef IPSEC 581 key_sa_routechange((struct sockaddr *)&icmpsrc); 582 #endif 583 break; 584 585 /* 586 * No kernel processing for the following; 587 * just fall through to send to raw listener. 588 */ 589 case ICMP_ECHOREPLY: 590 case ICMP_ROUTERADVERT: 591 case ICMP_ROUTERSOLICIT: 592 case ICMP_TSTAMPREPLY: 593 case ICMP_IREQREPLY: 594 case ICMP_MASKREPLY: 595 default: 596 break; 597 } 598 599 raw: 600 rip_input(m, off, proto); 601 return; 602 603 freeit: 604 m_freem(m); 605 } 606 607 /* 608 * Reflect the ip packet back to the source 609 */ 610 static void 611 icmp_reflect(m) 612 struct mbuf *m; 613 { 614 register struct ip *ip = mtod(m, struct ip *); 615 register struct in_ifaddr *ia; 616 struct in_addr t; 617 struct mbuf *opts = 0; 618 int optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 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 goto done; /* Ip_output() will check for broadcast */ 625 } 626 t = ip->ip_dst; 627 ip->ip_dst = ip->ip_src; 628 /* 629 * If the incoming packet was addressed directly to us, 630 * use dst as the src for the reply. Otherwise (broadcast 631 * or anonymous), use the address which corresponds 632 * to the incoming interface. 633 */ 634 for (ia = in_ifaddrhead.tqh_first; ia; ia = ia->ia_link.tqe_next) { 635 if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr) 636 break; 637 if (ia->ia_ifp && (ia->ia_ifp->if_flags & IFF_BROADCAST) && 638 t.s_addr == satosin(&ia->ia_broadaddr)->sin_addr.s_addr) 639 break; 640 } 641 icmpdst.sin_addr = t; 642 if ((ia == (struct in_ifaddr *)0) && m->m_pkthdr.rcvif) 643 ia = (struct in_ifaddr *)ifaof_ifpforaddr( 644 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif); 645 /* 646 * The following happens if the packet was not addressed to us, 647 * and was received on an interface with no IP address. 648 */ 649 if (ia == (struct in_ifaddr *)0) 650 ia = in_ifaddrhead.tqh_first; 651 t = IA_SIN(ia)->sin_addr; 652 ip->ip_src = t; 653 ip->ip_ttl = MAXTTL; 654 655 if (optlen > 0) { 656 register u_char *cp; 657 int opt, cnt; 658 u_int len; 659 660 /* 661 * Retrieve any source routing from the incoming packet; 662 * add on any record-route or timestamp options. 663 */ 664 cp = (u_char *) (ip + 1); 665 if ((opts = ip_srcroute()) == 0 && 666 (opts = m_gethdr(M_DONTWAIT, MT_HEADER))) { 667 opts->m_len = sizeof(struct in_addr); 668 mtod(opts, struct in_addr *)->s_addr = 0; 669 } 670 if (opts) { 671 #ifdef ICMPPRINTFS 672 if (icmpprintfs) 673 printf("icmp_reflect optlen %d rt %d => ", 674 optlen, opts->m_len); 675 #endif 676 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { 677 opt = cp[IPOPT_OPTVAL]; 678 if (opt == IPOPT_EOL) 679 break; 680 if (opt == IPOPT_NOP) 681 len = 1; 682 else { 683 if (cnt < IPOPT_OLEN + sizeof(*cp)) 684 break; 685 len = cp[IPOPT_OLEN]; 686 if (len < IPOPT_OLEN + sizeof(*cp) || 687 len > cnt) 688 break; 689 } 690 /* 691 * Should check for overflow, but it "can't happen" 692 */ 693 if (opt == IPOPT_RR || opt == IPOPT_TS || 694 opt == IPOPT_SECURITY) { 695 bcopy((caddr_t)cp, 696 mtod(opts, caddr_t) + opts->m_len, len); 697 opts->m_len += len; 698 } 699 } 700 /* Terminate & pad, if necessary */ 701 cnt = opts->m_len % 4; 702 if (cnt) { 703 for (; cnt < 4; cnt++) { 704 *(mtod(opts, caddr_t) + opts->m_len) = 705 IPOPT_EOL; 706 opts->m_len++; 707 } 708 } 709 #ifdef ICMPPRINTFS 710 if (icmpprintfs) 711 printf("%d\n", opts->m_len); 712 #endif 713 } 714 /* 715 * Now strip out original options by copying rest of first 716 * mbuf's data back, and adjust the IP length. 717 */ 718 ip->ip_len -= optlen; 719 ip->ip_vhl = IP_VHL_BORING; 720 m->m_len -= optlen; 721 if (m->m_flags & M_PKTHDR) 722 m->m_pkthdr.len -= optlen; 723 optlen += sizeof(struct ip); 724 bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1), 725 (unsigned)(m->m_len - sizeof(struct ip))); 726 } 727 m->m_flags &= ~(M_BCAST|M_MCAST); 728 icmp_send(m, opts); 729 done: 730 if (opts) 731 (void)m_free(opts); 732 } 733 734 /* 735 * Send an icmp packet back to the ip level, 736 * after supplying a checksum. 737 */ 738 static void 739 icmp_send(m, opts) 740 register struct mbuf *m; 741 struct mbuf *opts; 742 { 743 register struct ip *ip = mtod(m, struct ip *); 744 register int hlen; 745 register struct icmp *icp; 746 struct route ro; 747 748 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 749 m->m_data += hlen; 750 m->m_len -= hlen; 751 icp = mtod(m, struct icmp *); 752 icp->icmp_cksum = 0; 753 icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen); 754 m->m_data -= hlen; 755 m->m_len += hlen; 756 m->m_pkthdr.rcvif = (struct ifnet *)0; 757 #ifdef ICMPPRINTFS 758 if (icmpprintfs) { 759 char buf[4 * sizeof "123"]; 760 strcpy(buf, inet_ntoa(ip->ip_dst)); 761 printf("icmp_send dst %s src %s\n", 762 buf, inet_ntoa(ip->ip_src)); 763 } 764 #endif 765 bzero(&ro, sizeof ro); 766 (void) ip_output(m, opts, &ro, 0, NULL); 767 if (ro.ro_rt) 768 RTFREE(ro.ro_rt); 769 } 770 771 n_time 772 iptime() 773 { 774 struct timeval atv; 775 u_long t; 776 777 getmicrotime(&atv); 778 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; 779 return (htonl(t)); 780 } 781 782 #if 1 783 /* 784 * Return the next larger or smaller MTU plateau (table from RFC 1191) 785 * given current value MTU. If DIR is less than zero, a larger plateau 786 * is returned; otherwise, a smaller value is returned. 787 */ 788 static int 789 ip_next_mtu(mtu, dir) 790 int mtu; 791 int dir; 792 { 793 static int mtutab[] = { 794 65535, 32000, 17914, 8166, 4352, 2002, 1492, 1006, 508, 296, 795 68, 0 796 }; 797 int i; 798 799 for (i = 0; i < (sizeof mtutab) / (sizeof mtutab[0]); i++) { 800 if (mtu >= mtutab[i]) 801 break; 802 } 803 804 if (dir < 0) { 805 if (i == 0) { 806 return 0; 807 } else { 808 return mtutab[i - 1]; 809 } 810 } else { 811 if (mtutab[i] == 0) { 812 return 0; 813 } else if(mtu > mtutab[i]) { 814 return mtutab[i]; 815 } else { 816 return mtutab[i + 1]; 817 } 818 } 819 } 820 #endif 821 822 823 /* 824 * badport_bandlim() - check for ICMP bandwidth limit 825 * 826 * Return 0 if it is ok to send an ICMP error response, -1 if we have 827 * hit our bandwidth limit and it is not ok. 828 * 829 * If icmplim is <= 0, the feature is disabled and 0 is returned. 830 * 831 * For now we separate the TCP and UDP subsystems w/ different 'which' 832 * values. We may eventually remove this separation (and simplify the 833 * code further). 834 * 835 * Note that the printing of the error message is delayed so we can 836 * properly print the icmp error rate that the system was trying to do 837 * (i.e. 22000/100 pps, etc...). This can cause long delays in printing 838 * the 'final' error, but it doesn't make sense to solve the printing 839 * delay with more complex code. 840 */ 841 842 int 843 badport_bandlim(int which) 844 { 845 static int lticks[BANDLIM_MAX + 1]; 846 static int lpackets[BANDLIM_MAX + 1]; 847 int dticks; 848 const char *bandlimittype[] = { 849 "Limiting icmp unreach response", 850 "Limiting closed port RST response", 851 "Limiting open port RST response", 852 "Limiting icmp ping response", 853 "Limiting icmp tstamp response" 854 }; 855 856 /* 857 * Return ok status if feature disabled or argument out of 858 * ranage. 859 */ 860 861 if (icmplim <= 0 || which > BANDLIM_MAX || which < 0) 862 return(0); 863 dticks = ticks - lticks[which]; 864 865 /* 866 * reset stats when cumulative dt exceeds one second. 867 */ 868 869 if ((unsigned int)dticks > hz) { 870 if (lpackets[which] > icmplim && icmplim_output) { 871 printf("%s from %d to %d packets per second\n", 872 bandlimittype[which], 873 lpackets[which], 874 icmplim 875 ); 876 } 877 lticks[which] = ticks; 878 lpackets[which] = 0; 879 } 880 881 /* 882 * bump packet count 883 */ 884 885 if (++lpackets[which] > icmplim) { 886 return(-1); 887 } 888 return(0); 889 } 890 891