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 /* 71 * ICMP routines: error generation, receive packet processing, and 72 * routines to turnaround packets back to the originator, and 73 * host table maintenance routines. 74 */ 75 76 static struct icmpstat icmpstat; 77 SYSCTL_STRUCT(_net_inet_icmp, ICMPCTL_STATS, stats, CTLFLAG_RD, 78 &icmpstat, icmpstat, ""); 79 80 static int icmpmaskrepl = 0; 81 SYSCTL_INT(_net_inet_icmp, ICMPCTL_MASKREPL, maskrepl, CTLFLAG_RW, 82 &icmpmaskrepl, 0, ""); 83 84 static int drop_redirect = 0; 85 SYSCTL_INT(_net_inet_icmp, OID_AUTO, drop_redirect, CTLFLAG_RW, 86 &drop_redirect, 0, ""); 87 88 static int log_redirect = 0; 89 SYSCTL_INT(_net_inet_icmp, OID_AUTO, log_redirect, CTLFLAG_RW, 90 &log_redirect, 0, ""); 91 92 #ifdef ICMP_BANDLIM 93 94 /* 95 * ICMP error-response bandwidth limiting sysctl. If not enabled, sysctl 96 * variable content is -1 and read-only. 97 */ 98 99 static int icmplim = 200; 100 SYSCTL_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_RW, 101 &icmplim, 0, ""); 102 #else 103 104 static int icmplim = -1; 105 SYSCTL_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_RD, 106 &icmplim, 0, ""); 107 108 #endif 109 110 /* 111 * ICMP broadcast echo sysctl 112 */ 113 114 static int icmpbmcastecho = 0; 115 SYSCTL_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_RW, 116 &icmpbmcastecho, 0, ""); 117 118 119 #ifdef ICMPPRINTFS 120 int icmpprintfs = 0; 121 #endif 122 123 static void icmp_reflect __P((struct mbuf *)); 124 static void icmp_send __P((struct mbuf *, struct mbuf *)); 125 static int ip_next_mtu __P((int, int)); 126 127 extern struct protosw inetsw[]; 128 129 /* 130 * Generate an error packet of type error 131 * in response to bad packet ip. 132 */ 133 void 134 icmp_error(n, type, code, dest, destifp) 135 struct mbuf *n; 136 int type, code; 137 n_long dest; 138 struct ifnet *destifp; 139 { 140 register struct ip *oip = mtod(n, struct ip *), *nip; 141 register unsigned oiplen = IP_VHL_HL(oip->ip_vhl) << 2; 142 register struct icmp *icp; 143 register struct mbuf *m; 144 unsigned icmplen; 145 146 #ifdef ICMPPRINTFS 147 if (icmpprintfs) 148 printf("icmp_error(%p, %x, %d)\n", oip, type, code); 149 #endif 150 if (type != ICMP_REDIRECT) 151 icmpstat.icps_error++; 152 /* 153 * Don't send error if not the first fragment of message. 154 * Don't error if the old packet protocol was ICMP 155 * error message, only known informational types. 156 */ 157 if (oip->ip_off &~ (IP_MF|IP_DF)) 158 goto freeit; 159 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && 160 n->m_len >= oiplen + ICMP_MINLEN && 161 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiplen))->icmp_type)) { 162 icmpstat.icps_oldicmp++; 163 goto freeit; 164 } 165 /* Don't send error in response to a multicast or broadcast packet */ 166 if (n->m_flags & (M_BCAST|M_MCAST)) 167 goto freeit; 168 /* 169 * First, formulate icmp message 170 */ 171 m = m_gethdr(M_DONTWAIT, MT_HEADER); 172 if (m == NULL) 173 goto freeit; 174 icmplen = oiplen + min(8, oip->ip_len); 175 m->m_len = icmplen + ICMP_MINLEN; 176 MH_ALIGN(m, m->m_len); 177 icp = mtod(m, struct icmp *); 178 if ((u_int)type > ICMP_MAXTYPE) 179 panic("icmp_error"); 180 icmpstat.icps_outhist[type]++; 181 icp->icmp_type = type; 182 if (type == ICMP_REDIRECT) 183 icp->icmp_gwaddr.s_addr = dest; 184 else { 185 icp->icmp_void = 0; 186 /* 187 * The following assignments assume an overlay with the 188 * zeroed icmp_void field. 189 */ 190 if (type == ICMP_PARAMPROB) { 191 icp->icmp_pptr = code; 192 code = 0; 193 } else if (type == ICMP_UNREACH && 194 code == ICMP_UNREACH_NEEDFRAG && destifp) { 195 icp->icmp_nextmtu = htons(destifp->if_mtu); 196 } 197 } 198 199 icp->icmp_code = code; 200 bcopy((caddr_t)oip, (caddr_t)&icp->icmp_ip, icmplen); 201 nip = &icp->icmp_ip; 202 nip->ip_len = htons((u_short)(nip->ip_len + oiplen)); 203 204 /* 205 * Now, copy old ip header (without options) 206 * in front of icmp message. 207 */ 208 if (m->m_data - sizeof(struct ip) < m->m_pktdat) 209 panic("icmp len"); 210 m->m_data -= sizeof(struct ip); 211 m->m_len += sizeof(struct ip); 212 m->m_pkthdr.len = m->m_len; 213 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif; 214 nip = mtod(m, struct ip *); 215 bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip)); 216 nip->ip_len = m->m_len; 217 nip->ip_vhl = IP_VHL_BORING; 218 nip->ip_p = IPPROTO_ICMP; 219 nip->ip_tos = 0; 220 icmp_reflect(m); 221 222 freeit: 223 m_freem(n); 224 } 225 226 static struct sockaddr_in icmpsrc = { sizeof (struct sockaddr_in), AF_INET }; 227 static struct sockaddr_in icmpdst = { sizeof (struct sockaddr_in), AF_INET }; 228 static struct sockaddr_in icmpgw = { sizeof (struct sockaddr_in), AF_INET }; 229 230 /* 231 * Process a received ICMP message. 232 */ 233 void 234 icmp_input(m, off, proto) 235 register struct mbuf *m; 236 int off, proto; 237 { 238 int hlen = off; 239 register struct icmp *icp; 240 register struct ip *ip = mtod(m, struct ip *); 241 int icmplen = ip->ip_len; 242 register int i; 243 struct in_ifaddr *ia; 244 void (*ctlfunc) __P((int, struct sockaddr *, void *)); 245 int code; 246 247 /* 248 * Locate icmp structure in mbuf, and check 249 * that not corrupted and of at least minimum length. 250 */ 251 #ifdef ICMPPRINTFS 252 if (icmpprintfs) { 253 char buf[4 * sizeof "123"]; 254 strcpy(buf, inet_ntoa(ip->ip_src)); 255 printf("icmp_input from %s to %s, len %d\n", 256 buf, inet_ntoa(ip->ip_dst), icmplen); 257 } 258 #endif 259 if (icmplen < ICMP_MINLEN) { 260 icmpstat.icps_tooshort++; 261 goto freeit; 262 } 263 i = hlen + min(icmplen, ICMP_ADVLENMIN); 264 if (m->m_len < i && (m = m_pullup(m, i)) == 0) { 265 icmpstat.icps_tooshort++; 266 return; 267 } 268 ip = mtod(m, struct ip *); 269 m->m_len -= hlen; 270 m->m_data += hlen; 271 icp = mtod(m, struct icmp *); 272 if (in_cksum(m, icmplen)) { 273 icmpstat.icps_checksum++; 274 goto freeit; 275 } 276 m->m_len += hlen; 277 m->m_data -= hlen; 278 279 #if defined(NFAITH) && 0 < NFAITH 280 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 281 /* 282 * Deliver very specific ICMP type only. 283 */ 284 switch (icp->icmp_type) { 285 case ICMP_UNREACH: 286 case ICMP_TIMXCEED: 287 break; 288 default: 289 goto freeit; 290 } 291 } 292 #endif 293 294 #ifdef ICMPPRINTFS 295 if (icmpprintfs) 296 printf("icmp_input, type %d code %d\n", icp->icmp_type, 297 icp->icmp_code); 298 #endif 299 300 #ifdef IPSEC 301 /* drop it if it does not match the policy */ 302 /* XXX Is there meaning of check in here ? */ 303 if (ipsec4_in_reject(m, NULL)) { 304 ipsecstat.in_polvio++; 305 goto freeit; 306 } 307 #endif 308 309 /* 310 * Message type specific processing. 311 */ 312 if (icp->icmp_type > ICMP_MAXTYPE) 313 goto raw; 314 icmpstat.icps_inhist[icp->icmp_type]++; 315 code = icp->icmp_code; 316 switch (icp->icmp_type) { 317 318 case ICMP_UNREACH: 319 switch (code) { 320 case ICMP_UNREACH_NET: 321 case ICMP_UNREACH_HOST: 322 case ICMP_UNREACH_PROTOCOL: 323 case ICMP_UNREACH_PORT: 324 case ICMP_UNREACH_SRCFAIL: 325 code += PRC_UNREACH_NET; 326 break; 327 328 case ICMP_UNREACH_NEEDFRAG: 329 code = PRC_MSGSIZE; 330 break; 331 332 case ICMP_UNREACH_NET_UNKNOWN: 333 case ICMP_UNREACH_NET_PROHIB: 334 case ICMP_UNREACH_TOSNET: 335 code = PRC_UNREACH_NET; 336 break; 337 338 case ICMP_UNREACH_HOST_UNKNOWN: 339 case ICMP_UNREACH_ISOLATED: 340 case ICMP_UNREACH_HOST_PROHIB: 341 case ICMP_UNREACH_TOSHOST: 342 code = PRC_UNREACH_HOST; 343 break; 344 345 case ICMP_UNREACH_FILTER_PROHIB: 346 case ICMP_UNREACH_HOST_PRECEDENCE: 347 case ICMP_UNREACH_PRECEDENCE_CUTOFF: 348 code = PRC_UNREACH_PORT; 349 break; 350 351 default: 352 goto badcode; 353 } 354 goto deliver; 355 356 case ICMP_TIMXCEED: 357 if (code > 1) 358 goto badcode; 359 code += PRC_TIMXCEED_INTRANS; 360 goto deliver; 361 362 case ICMP_PARAMPROB: 363 if (code > 1) 364 goto badcode; 365 code = PRC_PARAMPROB; 366 goto deliver; 367 368 case ICMP_SOURCEQUENCH: 369 if (code) 370 goto badcode; 371 code = PRC_QUENCH; 372 deliver: 373 /* 374 * Problem with datagram; advise higher level routines. 375 */ 376 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 377 IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) { 378 icmpstat.icps_badlen++; 379 goto freeit; 380 } 381 NTOHS(icp->icmp_ip.ip_len); 382 /* Discard ICMP's in response to multicast packets */ 383 if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr))) 384 goto badcode; 385 #ifdef ICMPPRINTFS 386 if (icmpprintfs) 387 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p); 388 #endif 389 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 390 #if 1 391 /* 392 * MTU discovery: 393 * If we got a needfrag and there is a host route to the 394 * original destination, and the MTU is not locked, then 395 * set the MTU in the route to the suggested new value 396 * (if given) and then notify as usual. The ULPs will 397 * notice that the MTU has changed and adapt accordingly. 398 * If no new MTU was suggested, then we guess a new one 399 * less than the current value. If the new MTU is 400 * unreasonably small (arbitrarily set at 296), then 401 * we reset the MTU to the interface value and enable the 402 * lock bit, indicating that we are no longer doing MTU 403 * discovery. 404 */ 405 if (code == PRC_MSGSIZE) { 406 struct rtentry *rt; 407 int mtu; 408 409 rt = rtalloc1((struct sockaddr *)&icmpsrc, 0, 410 RTF_CLONING | RTF_PRCLONING); 411 if (rt && (rt->rt_flags & RTF_HOST) 412 && !(rt->rt_rmx.rmx_locks & RTV_MTU)) { 413 mtu = ntohs(icp->icmp_nextmtu); 414 if (!mtu) 415 mtu = ip_next_mtu(rt->rt_rmx.rmx_mtu, 416 1); 417 #ifdef DEBUG_MTUDISC 418 printf("MTU for %s reduced to %d\n", 419 inet_ntoa(icmpsrc.sin_addr), mtu); 420 #endif 421 if (mtu < 296) { 422 /* rt->rt_rmx.rmx_mtu = 423 rt->rt_ifp->if_mtu; */ 424 rt->rt_rmx.rmx_locks |= RTV_MTU; 425 } else if (rt->rt_rmx.rmx_mtu > mtu) { 426 rt->rt_rmx.rmx_mtu = mtu; 427 } 428 } 429 if (rt) 430 RTFREE(rt); 431 } 432 433 #endif 434 /* 435 * XXX if the packet contains [IPv4 AH TCP], we can't make a 436 * notification to TCP layer. 437 */ 438 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput; 439 if (ctlfunc) 440 (*ctlfunc)(code, (struct sockaddr *)&icmpsrc, 441 (void *)&icp->icmp_ip); 442 break; 443 444 badcode: 445 icmpstat.icps_badcode++; 446 break; 447 448 case ICMP_ECHO: 449 if (!icmpbmcastecho 450 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) { 451 icmpstat.icps_bmcastecho++; 452 break; 453 } 454 icp->icmp_type = ICMP_ECHOREPLY; 455 goto reflect; 456 457 case ICMP_TSTAMP: 458 if (!icmpbmcastecho 459 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) { 460 icmpstat.icps_bmcasttstamp++; 461 break; 462 } 463 if (icmplen < ICMP_TSLEN) { 464 icmpstat.icps_badlen++; 465 break; 466 } 467 icp->icmp_type = ICMP_TSTAMPREPLY; 468 icp->icmp_rtime = iptime(); 469 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ 470 goto reflect; 471 472 case ICMP_MASKREQ: 473 #define satosin(sa) ((struct sockaddr_in *)(sa)) 474 if (icmpmaskrepl == 0) 475 break; 476 /* 477 * We are not able to respond with all ones broadcast 478 * unless we receive it over a point-to-point interface. 479 */ 480 if (icmplen < ICMP_MASKLEN) 481 break; 482 switch (ip->ip_dst.s_addr) { 483 484 case INADDR_BROADCAST: 485 case INADDR_ANY: 486 icmpdst.sin_addr = ip->ip_src; 487 break; 488 489 default: 490 icmpdst.sin_addr = ip->ip_dst; 491 } 492 ia = (struct in_ifaddr *)ifaof_ifpforaddr( 493 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif); 494 if (ia == 0) 495 break; 496 if (ia->ia_ifp == 0) 497 break; 498 icp->icmp_type = ICMP_MASKREPLY; 499 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; 500 if (ip->ip_src.s_addr == 0) { 501 if (ia->ia_ifp->if_flags & IFF_BROADCAST) 502 ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr; 503 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) 504 ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr; 505 } 506 reflect: 507 ip->ip_len += hlen; /* since ip_input deducts this */ 508 icmpstat.icps_reflect++; 509 icmpstat.icps_outhist[icp->icmp_type]++; 510 icmp_reflect(m); 511 return; 512 513 case ICMP_REDIRECT: 514 if (log_redirect) { 515 u_long src, dst, gw; 516 517 src = ntohl(ip->ip_src.s_addr); 518 dst = ntohl(icp->icmp_ip.ip_dst.s_addr); 519 gw = ntohl(icp->icmp_gwaddr.s_addr); 520 printf("icmp redirect from %d.%d.%d.%d: " 521 "%d.%d.%d.%d => %d.%d.%d.%d\n", 522 (int)(src >> 24), (int)((src >> 16) & 0xff), 523 (int)((src >> 8) & 0xff), (int)(src & 0xff), 524 (int)(dst >> 24), (int)((dst >> 16) & 0xff), 525 (int)((dst >> 8) & 0xff), (int)(dst & 0xff), 526 (int)(gw >> 24), (int)((gw >> 16) & 0xff), 527 (int)((gw >> 8) & 0xff), (int)(gw & 0xff)); 528 } 529 if (drop_redirect) 530 break; 531 if (code > 3) 532 goto badcode; 533 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 534 IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) { 535 icmpstat.icps_badlen++; 536 break; 537 } 538 /* 539 * Short circuit routing redirects to force 540 * immediate change in the kernel's routing 541 * tables. The message is also handed to anyone 542 * listening on a raw socket (e.g. the routing 543 * daemon for use in updating its tables). 544 */ 545 icmpgw.sin_addr = ip->ip_src; 546 icmpdst.sin_addr = icp->icmp_gwaddr; 547 #ifdef ICMPPRINTFS 548 if (icmpprintfs) { 549 char buf[4 * sizeof "123"]; 550 strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst)); 551 552 printf("redirect dst %s to %s\n", 553 buf, inet_ntoa(icp->icmp_gwaddr)); 554 } 555 #endif 556 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 557 rtredirect((struct sockaddr *)&icmpsrc, 558 (struct sockaddr *)&icmpdst, 559 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST, 560 (struct sockaddr *)&icmpgw, (struct rtentry **)0); 561 pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc); 562 #ifdef IPSEC 563 key_sa_routechange((struct sockaddr *)&icmpsrc); 564 #endif 565 break; 566 567 /* 568 * No kernel processing for the following; 569 * just fall through to send to raw listener. 570 */ 571 case ICMP_ECHOREPLY: 572 case ICMP_ROUTERADVERT: 573 case ICMP_ROUTERSOLICIT: 574 case ICMP_TSTAMPREPLY: 575 case ICMP_IREQREPLY: 576 case ICMP_MASKREPLY: 577 default: 578 break; 579 } 580 581 raw: 582 rip_input(m, off, proto); 583 return; 584 585 freeit: 586 m_freem(m); 587 } 588 589 /* 590 * Reflect the ip packet back to the source 591 */ 592 static void 593 icmp_reflect(m) 594 struct mbuf *m; 595 { 596 register struct ip *ip = mtod(m, struct ip *); 597 register struct in_ifaddr *ia; 598 struct in_addr t; 599 struct mbuf *opts = 0; 600 int optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 601 602 if (!in_canforward(ip->ip_src) && 603 ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) != 604 (IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) { 605 m_freem(m); /* Bad return address */ 606 goto done; /* Ip_output() will check for broadcast */ 607 } 608 t = ip->ip_dst; 609 ip->ip_dst = ip->ip_src; 610 /* 611 * If the incoming packet was addressed directly to us, 612 * use dst as the src for the reply. Otherwise (broadcast 613 * or anonymous), use the address which corresponds 614 * to the incoming interface. 615 */ 616 for (ia = in_ifaddrhead.tqh_first; ia; ia = ia->ia_link.tqe_next) { 617 if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr) 618 break; 619 if (ia->ia_ifp && (ia->ia_ifp->if_flags & IFF_BROADCAST) && 620 t.s_addr == satosin(&ia->ia_broadaddr)->sin_addr.s_addr) 621 break; 622 } 623 icmpdst.sin_addr = t; 624 if ((ia == (struct in_ifaddr *)0) && m->m_pkthdr.rcvif) 625 ia = (struct in_ifaddr *)ifaof_ifpforaddr( 626 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif); 627 /* 628 * The following happens if the packet was not addressed to us, 629 * and was received on an interface with no IP address. 630 */ 631 if (ia == (struct in_ifaddr *)0) 632 ia = in_ifaddrhead.tqh_first; 633 t = IA_SIN(ia)->sin_addr; 634 ip->ip_src = t; 635 ip->ip_ttl = MAXTTL; 636 637 if (optlen > 0) { 638 register u_char *cp; 639 int opt, cnt; 640 u_int len; 641 642 /* 643 * Retrieve any source routing from the incoming packet; 644 * add on any record-route or timestamp options. 645 */ 646 cp = (u_char *) (ip + 1); 647 if ((opts = ip_srcroute()) == 0 && 648 (opts = m_gethdr(M_DONTWAIT, MT_HEADER))) { 649 opts->m_len = sizeof(struct in_addr); 650 mtod(opts, struct in_addr *)->s_addr = 0; 651 } 652 if (opts) { 653 #ifdef ICMPPRINTFS 654 if (icmpprintfs) 655 printf("icmp_reflect optlen %d rt %d => ", 656 optlen, opts->m_len); 657 #endif 658 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { 659 opt = cp[IPOPT_OPTVAL]; 660 if (opt == IPOPT_EOL) 661 break; 662 if (opt == IPOPT_NOP) 663 len = 1; 664 else { 665 len = cp[IPOPT_OLEN]; 666 if (len <= 0 || len > cnt) 667 break; 668 } 669 /* 670 * Should check for overflow, but it "can't happen" 671 */ 672 if (opt == IPOPT_RR || opt == IPOPT_TS || 673 opt == IPOPT_SECURITY) { 674 bcopy((caddr_t)cp, 675 mtod(opts, caddr_t) + opts->m_len, len); 676 opts->m_len += len; 677 } 678 } 679 /* Terminate & pad, if necessary */ 680 cnt = opts->m_len % 4; 681 if (cnt) { 682 for (; cnt < 4; cnt++) { 683 *(mtod(opts, caddr_t) + opts->m_len) = 684 IPOPT_EOL; 685 opts->m_len++; 686 } 687 } 688 #ifdef ICMPPRINTFS 689 if (icmpprintfs) 690 printf("%d\n", opts->m_len); 691 #endif 692 } 693 /* 694 * Now strip out original options by copying rest of first 695 * mbuf's data back, and adjust the IP length. 696 */ 697 ip->ip_len -= optlen; 698 ip->ip_vhl = IP_VHL_BORING; 699 m->m_len -= optlen; 700 if (m->m_flags & M_PKTHDR) 701 m->m_pkthdr.len -= optlen; 702 optlen += sizeof(struct ip); 703 bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1), 704 (unsigned)(m->m_len - sizeof(struct ip))); 705 } 706 m->m_flags &= ~(M_BCAST|M_MCAST); 707 icmp_send(m, opts); 708 done: 709 if (opts) 710 (void)m_free(opts); 711 } 712 713 /* 714 * Send an icmp packet back to the ip level, 715 * after supplying a checksum. 716 */ 717 static void 718 icmp_send(m, opts) 719 register struct mbuf *m; 720 struct mbuf *opts; 721 { 722 register struct ip *ip = mtod(m, struct ip *); 723 register int hlen; 724 register struct icmp *icp; 725 struct route ro; 726 727 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 728 m->m_data += hlen; 729 m->m_len -= hlen; 730 icp = mtod(m, struct icmp *); 731 icp->icmp_cksum = 0; 732 icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen); 733 m->m_data -= hlen; 734 m->m_len += hlen; 735 m->m_pkthdr.rcvif = (struct ifnet *)0; 736 #ifdef ICMPPRINTFS 737 if (icmpprintfs) { 738 char buf[4 * sizeof "123"]; 739 strcpy(buf, inet_ntoa(ip->ip_dst)); 740 printf("icmp_send dst %s src %s\n", 741 buf, inet_ntoa(ip->ip_src)); 742 } 743 #endif 744 bzero(&ro, sizeof ro); 745 (void) ip_output(m, opts, &ro, 0, NULL); 746 if (ro.ro_rt) 747 RTFREE(ro.ro_rt); 748 } 749 750 n_time 751 iptime() 752 { 753 struct timeval atv; 754 u_long t; 755 756 microtime(&atv); 757 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; 758 return (htonl(t)); 759 } 760 761 #if 1 762 /* 763 * Return the next larger or smaller MTU plateau (table from RFC 1191) 764 * given current value MTU. If DIR is less than zero, a larger plateau 765 * is returned; otherwise, a smaller value is returned. 766 */ 767 static int 768 ip_next_mtu(mtu, dir) 769 int mtu; 770 int dir; 771 { 772 static int mtutab[] = { 773 65535, 32000, 17914, 8166, 4352, 2002, 1492, 1006, 508, 296, 774 68, 0 775 }; 776 int i; 777 778 for (i = 0; i < (sizeof mtutab) / (sizeof mtutab[0]); i++) { 779 if (mtu >= mtutab[i]) 780 break; 781 } 782 783 if (dir < 0) { 784 if (i == 0) { 785 return 0; 786 } else { 787 return mtutab[i - 1]; 788 } 789 } else { 790 if (mtutab[i] == 0) { 791 return 0; 792 } else if(mtu > mtutab[i]) { 793 return mtutab[i]; 794 } else { 795 return mtutab[i + 1]; 796 } 797 } 798 } 799 #endif 800 801 #ifdef ICMP_BANDLIM 802 803 /* 804 * badport_bandlim() - check for ICMP bandwidth limit 805 * 806 * Return 0 if it is ok to send an ICMP error response, -1 if we have 807 * hit our bandwidth limit and it is not ok. 808 * 809 * If icmplim is <= 0, the feature is disabled and 0 is returned. 810 * 811 * For now we separate the TCP and UDP subsystems w/ different 'which' 812 * values. We may eventually remove this separation (and simplify the 813 * code further). 814 * 815 * Note that the printing of the error message is delayed so we can 816 * properly print the icmp error rate that the system was trying to do 817 * (i.e. 22000/100 pps, etc...). This can cause long delays in printing 818 * the 'final' error, but it doesn't make sense to solve the printing 819 * delay with more complex code. 820 */ 821 822 int 823 badport_bandlim(int which) 824 { 825 static int lticks[2]; 826 static int lpackets[2]; 827 int dticks; 828 829 /* 830 * Return ok status if feature disabled or argument out of 831 * ranage. 832 */ 833 834 if (icmplim <= 0 || which >= 2 || which < 0) 835 return(0); 836 dticks = ticks - lticks[which]; 837 838 /* 839 * reset stats when cumulative dt exceeds one second. 840 */ 841 842 if ((unsigned int)dticks > hz) { 843 if (lpackets[which] > icmplim) { 844 printf("icmp-response bandwidth limit %d/%d pps\n", 845 lpackets[which], 846 icmplim 847 ); 848 } 849 lticks[which] = ticks; 850 lpackets[which] = 0; 851 } 852 853 /* 854 * bump packet count 855 */ 856 857 if (++lpackets[which] > icmplim) { 858 return(-1); 859 } 860 return(0); 861 } 862 863 #endif 864 865 866