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