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sys/netinet/ip_icmp.c
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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 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD: releng/8.1/sys/netinet/ip_icmp.c 207695 2010-05-06 06:44:19Z bz $"); 34 35 #include "opt_ipsec.h" 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/mbuf.h> 40 #include <sys/protosw.h> 41 #include <sys/socket.h> 42 #include <sys/time.h> 43 #include <sys/kernel.h> 44 #include <sys/sysctl.h> 45 46 #include <net/if.h> 47 #include <net/if_types.h> 48 #include <net/route.h> 49 #include <net/vnet.h> 50 51 #include <netinet/in.h> 52 #include <netinet/in_pcb.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/ip_options.h> 59 #include <netinet/tcp.h> 60 #include <netinet/tcp_var.h> 61 #include <netinet/tcpip.h> 62 #include <netinet/icmp_var.h> 63 64 #ifdef IPSEC 65 #include <netipsec/ipsec.h> 66 #include <netipsec/key.h> 67 #endif 68 69 #include <machine/in_cksum.h> 70 71 #include <security/mac/mac_framework.h> 72 73 /* 74 * ICMP routines: error generation, receive packet processing, and 75 * routines to turnaround packets back to the originator, and 76 * host table maintenance routines. 77 */ 78 VNET_DEFINE(struct icmpstat, icmpstat); 79 SYSCTL_VNET_STRUCT(_net_inet_icmp, ICMPCTL_STATS, stats, CTLFLAG_RW, 80 &VNET_NAME(icmpstat), icmpstat, ""); 81 82 static VNET_DEFINE(int, icmpmaskrepl) = 0; 83 #define V_icmpmaskrepl VNET(icmpmaskrepl) 84 SYSCTL_VNET_INT(_net_inet_icmp, ICMPCTL_MASKREPL, maskrepl, CTLFLAG_RW, 85 &VNET_NAME(icmpmaskrepl), 0, 86 "Reply to ICMP Address Mask Request packets."); 87 88 static VNET_DEFINE(u_int, icmpmaskfake) = 0; 89 #define V_icmpmaskfake VNET(icmpmaskfake) 90 SYSCTL_VNET_UINT(_net_inet_icmp, OID_AUTO, maskfake, CTLFLAG_RW, 91 &VNET_NAME(icmpmaskfake), 0, 92 "Fake reply to ICMP Address Mask Request packets."); 93 94 static VNET_DEFINE(int, drop_redirect) = 0; 95 #define V_drop_redirect VNET(drop_redirect) 96 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, drop_redirect, CTLFLAG_RW, 97 &VNET_NAME(drop_redirect), 0, 98 "Ignore ICMP redirects"); 99 100 static VNET_DEFINE(int, log_redirect) = 0; 101 #define V_log_redirect VNET(log_redirect) 102 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, log_redirect, CTLFLAG_RW, 103 &VNET_NAME(log_redirect), 0, 104 "Log ICMP redirects to the console"); 105 106 static VNET_DEFINE(int, icmplim) = 200; 107 #define V_icmplim VNET(icmplim) 108 SYSCTL_VNET_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_RW, 109 &VNET_NAME(icmplim), 0, 110 "Maximum number of ICMP responses per second"); 111 112 static VNET_DEFINE(int, icmplim_output) = 1; 113 #define V_icmplim_output VNET(icmplim_output) 114 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, icmplim_output, CTLFLAG_RW, 115 &VNET_NAME(icmplim_output), 0, 116 "Enable rate limiting of ICMP responses"); 117 118 static VNET_DEFINE(char, reply_src[IFNAMSIZ]); 119 #define V_reply_src VNET(reply_src) 120 SYSCTL_VNET_STRING(_net_inet_icmp, OID_AUTO, reply_src, CTLFLAG_RW, 121 &VNET_NAME(reply_src), IFNAMSIZ, 122 "icmp reply source for non-local packets."); 123 124 static VNET_DEFINE(int, icmp_rfi) = 0; 125 #define V_icmp_rfi VNET(icmp_rfi) 126 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, reply_from_interface, CTLFLAG_RW, 127 &VNET_NAME(icmp_rfi), 0, 128 "ICMP reply from incoming interface for non-local packets"); 129 130 static VNET_DEFINE(int, icmp_quotelen) = 8; 131 #define V_icmp_quotelen VNET(icmp_quotelen) 132 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, quotelen, CTLFLAG_RW, 133 &VNET_NAME(icmp_quotelen), 0, 134 "Number of bytes from original packet to quote in ICMP reply"); 135 136 /* 137 * ICMP broadcast echo sysctl 138 */ 139 static VNET_DEFINE(int, icmpbmcastecho) = 0; 140 #define V_icmpbmcastecho VNET(icmpbmcastecho) 141 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_RW, 142 &VNET_NAME(icmpbmcastecho), 0, 143 ""); 144 145 146 #ifdef ICMPPRINTFS 147 int icmpprintfs = 0; 148 #endif 149 150 static void icmp_reflect(struct mbuf *); 151 static void icmp_send(struct mbuf *, struct mbuf *); 152 153 extern struct protosw inetsw[]; 154 155 /* 156 * Kernel module interface for updating icmpstat. The argument is an index 157 * into icmpstat treated as an array of u_long. While this encodes the 158 * general layout of icmpstat into the caller, it doesn't encode its 159 * location, so that future changes to add, for example, per-CPU stats 160 * support won't cause binary compatibility problems for kernel modules. 161 */ 162 void 163 kmod_icmpstat_inc(int statnum) 164 { 165 166 (*((u_long *)&V_icmpstat + statnum))++; 167 } 168 169 /* 170 * Generate an error packet of type error 171 * in response to bad packet ip. 172 */ 173 void 174 icmp_error(struct mbuf *n, int type, int code, uint32_t dest, int mtu) 175 { 176 register struct ip *oip = mtod(n, struct ip *), *nip; 177 register unsigned oiphlen = oip->ip_hl << 2; 178 register struct icmp *icp; 179 register struct mbuf *m; 180 unsigned icmplen, icmpelen, nlen; 181 182 KASSERT((u_int)type <= ICMP_MAXTYPE, ("%s: illegal ICMP type", __func__)); 183 #ifdef ICMPPRINTFS 184 if (icmpprintfs) 185 printf("icmp_error(%p, %x, %d)\n", oip, type, code); 186 #endif 187 if (type != ICMP_REDIRECT) 188 ICMPSTAT_INC(icps_error); 189 /* 190 * Don't send error: 191 * if the original packet was encrypted. 192 * if not the first fragment of message. 193 * in response to a multicast or broadcast packet. 194 * if the old packet protocol was an ICMP error message. 195 */ 196 if (n->m_flags & M_DECRYPTED) 197 goto freeit; 198 if (oip->ip_off & ~(IP_MF|IP_DF)) 199 goto freeit; 200 if (n->m_flags & (M_BCAST|M_MCAST)) 201 goto freeit; 202 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && 203 n->m_len >= oiphlen + ICMP_MINLEN && 204 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiphlen))->icmp_type)) { 205 ICMPSTAT_INC(icps_oldicmp); 206 goto freeit; 207 } 208 /* Drop if IP header plus 8 bytes is not contignous in first mbuf. */ 209 if (oiphlen + 8 > n->m_len) 210 goto freeit; 211 /* 212 * Calculate length to quote from original packet and 213 * prevent the ICMP mbuf from overflowing. 214 * Unfortunatly this is non-trivial since ip_forward() 215 * sends us truncated packets. 216 */ 217 nlen = m_length(n, NULL); 218 if (oip->ip_p == IPPROTO_TCP) { 219 struct tcphdr *th; 220 int tcphlen; 221 222 if (oiphlen + sizeof(struct tcphdr) > n->m_len && 223 n->m_next == NULL) 224 goto stdreply; 225 if (n->m_len < oiphlen + sizeof(struct tcphdr) && 226 ((n = m_pullup(n, oiphlen + sizeof(struct tcphdr))) == NULL)) 227 goto freeit; 228 th = (struct tcphdr *)((caddr_t)oip + oiphlen); 229 tcphlen = th->th_off << 2; 230 if (tcphlen < sizeof(struct tcphdr)) 231 goto freeit; 232 if (oip->ip_len < oiphlen + tcphlen) 233 goto freeit; 234 if (oiphlen + tcphlen > n->m_len && n->m_next == NULL) 235 goto stdreply; 236 if (n->m_len < oiphlen + tcphlen && 237 ((n = m_pullup(n, oiphlen + tcphlen)) == NULL)) 238 goto freeit; 239 icmpelen = max(tcphlen, min(V_icmp_quotelen, oip->ip_len - oiphlen)); 240 } else 241 stdreply: icmpelen = max(8, min(V_icmp_quotelen, oip->ip_len - oiphlen)); 242 243 icmplen = min(oiphlen + icmpelen, nlen); 244 if (icmplen < sizeof(struct ip)) 245 goto freeit; 246 247 if (MHLEN > sizeof(struct ip) + ICMP_MINLEN + icmplen) 248 m = m_gethdr(M_DONTWAIT, MT_DATA); 249 else 250 m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR); 251 if (m == NULL) 252 goto freeit; 253 #ifdef MAC 254 mac_netinet_icmp_reply(n, m); 255 #endif 256 icmplen = min(icmplen, M_TRAILINGSPACE(m) - sizeof(struct ip) - ICMP_MINLEN); 257 m_align(m, ICMP_MINLEN + icmplen); 258 m->m_len = ICMP_MINLEN + icmplen; 259 260 /* XXX MRT make the outgoing packet use the same FIB 261 * that was associated with the incoming packet 262 */ 263 M_SETFIB(m, M_GETFIB(n)); 264 icp = mtod(m, struct icmp *); 265 ICMPSTAT_INC(icps_outhist[type]); 266 icp->icmp_type = type; 267 if (type == ICMP_REDIRECT) 268 icp->icmp_gwaddr.s_addr = dest; 269 else { 270 icp->icmp_void = 0; 271 /* 272 * The following assignments assume an overlay with the 273 * just zeroed icmp_void field. 274 */ 275 if (type == ICMP_PARAMPROB) { 276 icp->icmp_pptr = code; 277 code = 0; 278 } else if (type == ICMP_UNREACH && 279 code == ICMP_UNREACH_NEEDFRAG && mtu) { 280 icp->icmp_nextmtu = htons(mtu); 281 } 282 } 283 icp->icmp_code = code; 284 285 /* 286 * Copy the quotation into ICMP message and 287 * convert quoted IP header back to network representation. 288 */ 289 m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip); 290 nip = &icp->icmp_ip; 291 nip->ip_len = htons(nip->ip_len); 292 nip->ip_off = htons(nip->ip_off); 293 294 /* 295 * Set up ICMP message mbuf and copy old IP header (without options 296 * in front of ICMP message. 297 * If the original mbuf was meant to bypass the firewall, the error 298 * reply should bypass as well. 299 */ 300 m->m_flags |= n->m_flags & M_SKIP_FIREWALL; 301 m->m_data -= sizeof(struct ip); 302 m->m_len += sizeof(struct ip); 303 m->m_pkthdr.len = m->m_len; 304 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif; 305 nip = mtod(m, struct ip *); 306 bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip)); 307 nip->ip_len = m->m_len; 308 nip->ip_v = IPVERSION; 309 nip->ip_hl = 5; 310 nip->ip_p = IPPROTO_ICMP; 311 nip->ip_tos = 0; 312 icmp_reflect(m); 313 314 freeit: 315 m_freem(n); 316 } 317 318 /* 319 * Process a received ICMP message. 320 */ 321 void 322 icmp_input(struct mbuf *m, int off) 323 { 324 struct icmp *icp; 325 struct in_ifaddr *ia; 326 struct ip *ip = mtod(m, struct ip *); 327 struct sockaddr_in icmpsrc, icmpdst, icmpgw; 328 int hlen = off; 329 int icmplen = ip->ip_len; 330 int i, code; 331 void (*ctlfunc)(int, struct sockaddr *, void *); 332 int fibnum; 333 334 /* 335 * Locate icmp structure in mbuf, and check 336 * that not corrupted and of at least minimum length. 337 */ 338 #ifdef ICMPPRINTFS 339 if (icmpprintfs) { 340 char buf[4 * sizeof "123"]; 341 strcpy(buf, inet_ntoa(ip->ip_src)); 342 printf("icmp_input from %s to %s, len %d\n", 343 buf, inet_ntoa(ip->ip_dst), icmplen); 344 } 345 #endif 346 if (icmplen < ICMP_MINLEN) { 347 ICMPSTAT_INC(icps_tooshort); 348 goto freeit; 349 } 350 i = hlen + min(icmplen, ICMP_ADVLENMIN); 351 if (m->m_len < i && (m = m_pullup(m, i)) == NULL) { 352 ICMPSTAT_INC(icps_tooshort); 353 return; 354 } 355 ip = mtod(m, struct ip *); 356 m->m_len -= hlen; 357 m->m_data += hlen; 358 icp = mtod(m, struct icmp *); 359 if (in_cksum(m, icmplen)) { 360 ICMPSTAT_INC(icps_checksum); 361 goto freeit; 362 } 363 m->m_len += hlen; 364 m->m_data -= hlen; 365 366 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 367 /* 368 * Deliver very specific ICMP type only. 369 */ 370 switch (icp->icmp_type) { 371 case ICMP_UNREACH: 372 case ICMP_TIMXCEED: 373 break; 374 default: 375 goto freeit; 376 } 377 } 378 379 #ifdef ICMPPRINTFS 380 if (icmpprintfs) 381 printf("icmp_input, type %d code %d\n", icp->icmp_type, 382 icp->icmp_code); 383 #endif 384 385 /* 386 * Message type specific processing. 387 */ 388 if (icp->icmp_type > ICMP_MAXTYPE) 389 goto raw; 390 391 /* Initialize */ 392 bzero(&icmpsrc, sizeof(icmpsrc)); 393 icmpsrc.sin_len = sizeof(struct sockaddr_in); 394 icmpsrc.sin_family = AF_INET; 395 bzero(&icmpdst, sizeof(icmpdst)); 396 icmpdst.sin_len = sizeof(struct sockaddr_in); 397 icmpdst.sin_family = AF_INET; 398 bzero(&icmpgw, sizeof(icmpgw)); 399 icmpgw.sin_len = sizeof(struct sockaddr_in); 400 icmpgw.sin_family = AF_INET; 401 402 ICMPSTAT_INC(icps_inhist[icp->icmp_type]); 403 code = icp->icmp_code; 404 switch (icp->icmp_type) { 405 406 case ICMP_UNREACH: 407 switch (code) { 408 case ICMP_UNREACH_NET: 409 case ICMP_UNREACH_HOST: 410 case ICMP_UNREACH_SRCFAIL: 411 case ICMP_UNREACH_NET_UNKNOWN: 412 case ICMP_UNREACH_HOST_UNKNOWN: 413 case ICMP_UNREACH_ISOLATED: 414 case ICMP_UNREACH_TOSNET: 415 case ICMP_UNREACH_TOSHOST: 416 case ICMP_UNREACH_HOST_PRECEDENCE: 417 case ICMP_UNREACH_PRECEDENCE_CUTOFF: 418 code = PRC_UNREACH_NET; 419 break; 420 421 case ICMP_UNREACH_NEEDFRAG: 422 code = PRC_MSGSIZE; 423 break; 424 425 /* 426 * RFC 1122, Sections 3.2.2.1 and 4.2.3.9. 427 * Treat subcodes 2,3 as immediate RST 428 */ 429 case ICMP_UNREACH_PROTOCOL: 430 case ICMP_UNREACH_PORT: 431 code = PRC_UNREACH_PORT; 432 break; 433 434 case ICMP_UNREACH_NET_PROHIB: 435 case ICMP_UNREACH_HOST_PROHIB: 436 case ICMP_UNREACH_FILTER_PROHIB: 437 code = PRC_UNREACH_ADMIN_PROHIB; 438 break; 439 440 default: 441 goto badcode; 442 } 443 goto deliver; 444 445 case ICMP_TIMXCEED: 446 if (code > 1) 447 goto badcode; 448 code += PRC_TIMXCEED_INTRANS; 449 goto deliver; 450 451 case ICMP_PARAMPROB: 452 if (code > 1) 453 goto badcode; 454 code = PRC_PARAMPROB; 455 goto deliver; 456 457 case ICMP_SOURCEQUENCH: 458 if (code) 459 goto badcode; 460 code = PRC_QUENCH; 461 deliver: 462 /* 463 * Problem with datagram; advise higher level routines. 464 */ 465 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 466 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 467 ICMPSTAT_INC(icps_badlen); 468 goto freeit; 469 } 470 icp->icmp_ip.ip_len = ntohs(icp->icmp_ip.ip_len); 471 /* Discard ICMP's in response to multicast packets */ 472 if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr))) 473 goto badcode; 474 #ifdef ICMPPRINTFS 475 if (icmpprintfs) 476 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p); 477 #endif 478 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 479 /* 480 * XXX if the packet contains [IPv4 AH TCP], we can't make a 481 * notification to TCP layer. 482 */ 483 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput; 484 if (ctlfunc) 485 (*ctlfunc)(code, (struct sockaddr *)&icmpsrc, 486 (void *)&icp->icmp_ip); 487 break; 488 489 badcode: 490 ICMPSTAT_INC(icps_badcode); 491 break; 492 493 case ICMP_ECHO: 494 if (!V_icmpbmcastecho 495 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) { 496 ICMPSTAT_INC(icps_bmcastecho); 497 break; 498 } 499 icp->icmp_type = ICMP_ECHOREPLY; 500 if (badport_bandlim(BANDLIM_ICMP_ECHO) < 0) 501 goto freeit; 502 else 503 goto reflect; 504 505 case ICMP_TSTAMP: 506 if (!V_icmpbmcastecho 507 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) { 508 ICMPSTAT_INC(icps_bmcasttstamp); 509 break; 510 } 511 if (icmplen < ICMP_TSLEN) { 512 ICMPSTAT_INC(icps_badlen); 513 break; 514 } 515 icp->icmp_type = ICMP_TSTAMPREPLY; 516 icp->icmp_rtime = iptime(); 517 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ 518 if (badport_bandlim(BANDLIM_ICMP_TSTAMP) < 0) 519 goto freeit; 520 else 521 goto reflect; 522 523 case ICMP_MASKREQ: 524 if (V_icmpmaskrepl == 0) 525 break; 526 /* 527 * We are not able to respond with all ones broadcast 528 * unless we receive it over a point-to-point interface. 529 */ 530 if (icmplen < ICMP_MASKLEN) 531 break; 532 switch (ip->ip_dst.s_addr) { 533 534 case INADDR_BROADCAST: 535 case INADDR_ANY: 536 icmpdst.sin_addr = ip->ip_src; 537 break; 538 539 default: 540 icmpdst.sin_addr = ip->ip_dst; 541 } 542 ia = (struct in_ifaddr *)ifaof_ifpforaddr( 543 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif); 544 if (ia == NULL) 545 break; 546 if (ia->ia_ifp == NULL) { 547 ifa_free(&ia->ia_ifa); 548 break; 549 } 550 icp->icmp_type = ICMP_MASKREPLY; 551 if (V_icmpmaskfake == 0) 552 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; 553 else 554 icp->icmp_mask = V_icmpmaskfake; 555 if (ip->ip_src.s_addr == 0) { 556 if (ia->ia_ifp->if_flags & IFF_BROADCAST) 557 ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr; 558 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) 559 ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr; 560 } 561 ifa_free(&ia->ia_ifa); 562 reflect: 563 ip->ip_len += hlen; /* since ip_input deducts this */ 564 ICMPSTAT_INC(icps_reflect); 565 ICMPSTAT_INC(icps_outhist[icp->icmp_type]); 566 icmp_reflect(m); 567 return; 568 569 case ICMP_REDIRECT: 570 if (V_log_redirect) { 571 u_long src, dst, gw; 572 573 src = ntohl(ip->ip_src.s_addr); 574 dst = ntohl(icp->icmp_ip.ip_dst.s_addr); 575 gw = ntohl(icp->icmp_gwaddr.s_addr); 576 printf("icmp redirect from %d.%d.%d.%d: " 577 "%d.%d.%d.%d => %d.%d.%d.%d\n", 578 (int)(src >> 24), (int)((src >> 16) & 0xff), 579 (int)((src >> 8) & 0xff), (int)(src & 0xff), 580 (int)(dst >> 24), (int)((dst >> 16) & 0xff), 581 (int)((dst >> 8) & 0xff), (int)(dst & 0xff), 582 (int)(gw >> 24), (int)((gw >> 16) & 0xff), 583 (int)((gw >> 8) & 0xff), (int)(gw & 0xff)); 584 } 585 /* 586 * RFC1812 says we must ignore ICMP redirects if we 587 * are acting as router. 588 */ 589 if (V_drop_redirect || V_ipforwarding) 590 break; 591 if (code > 3) 592 goto badcode; 593 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 594 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 595 ICMPSTAT_INC(icps_badlen); 596 break; 597 } 598 /* 599 * Short circuit routing redirects to force 600 * immediate change in the kernel's routing 601 * tables. The message is also handed to anyone 602 * listening on a raw socket (e.g. the routing 603 * daemon for use in updating its tables). 604 */ 605 icmpgw.sin_addr = ip->ip_src; 606 icmpdst.sin_addr = icp->icmp_gwaddr; 607 #ifdef ICMPPRINTFS 608 if (icmpprintfs) { 609 char buf[4 * sizeof "123"]; 610 strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst)); 611 612 printf("redirect dst %s to %s\n", 613 buf, inet_ntoa(icp->icmp_gwaddr)); 614 } 615 #endif 616 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 617 for ( fibnum = 0; fibnum < rt_numfibs; fibnum++) { 618 in_rtredirect((struct sockaddr *)&icmpsrc, 619 (struct sockaddr *)&icmpdst, 620 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST, 621 (struct sockaddr *)&icmpgw, fibnum); 622 } 623 pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc); 624 #ifdef IPSEC 625 key_sa_routechange((struct sockaddr *)&icmpsrc); 626 #endif 627 break; 628 629 /* 630 * No kernel processing for the following; 631 * just fall through to send to raw listener. 632 */ 633 case ICMP_ECHOREPLY: 634 case ICMP_ROUTERADVERT: 635 case ICMP_ROUTERSOLICIT: 636 case ICMP_TSTAMPREPLY: 637 case ICMP_IREQREPLY: 638 case ICMP_MASKREPLY: 639 default: 640 break; 641 } 642 643 raw: 644 rip_input(m, off); 645 return; 646 647 freeit: 648 m_freem(m); 649 } 650 651 /* 652 * Reflect the ip packet back to the source 653 */ 654 static void 655 icmp_reflect(struct mbuf *m) 656 { 657 struct ip *ip = mtod(m, struct ip *); 658 struct ifaddr *ifa; 659 struct ifnet *ifp; 660 struct in_ifaddr *ia; 661 struct in_addr t; 662 struct mbuf *opts = 0; 663 int optlen = (ip->ip_hl << 2) - sizeof(struct ip); 664 665 if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)) || 666 IN_EXPERIMENTAL(ntohl(ip->ip_src.s_addr)) || 667 IN_ZERONET(ntohl(ip->ip_src.s_addr)) ) { 668 m_freem(m); /* Bad return address */ 669 ICMPSTAT_INC(icps_badaddr); 670 goto done; /* Ip_output() will check for broadcast */ 671 } 672 673 t = ip->ip_dst; 674 ip->ip_dst = ip->ip_src; 675 676 /* 677 * Source selection for ICMP replies: 678 * 679 * If the incoming packet was addressed directly to one of our 680 * own addresses, use dst as the src for the reply. 681 */ 682 IN_IFADDR_RLOCK(); 683 LIST_FOREACH(ia, INADDR_HASH(t.s_addr), ia_hash) { 684 if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr) { 685 t = IA_SIN(ia)->sin_addr; 686 IN_IFADDR_RUNLOCK(); 687 goto match; 688 } 689 } 690 IN_IFADDR_RUNLOCK(); 691 692 /* 693 * If the incoming packet was addressed to one of our broadcast 694 * addresses, use the first non-broadcast address which corresponds 695 * to the incoming interface. 696 */ 697 ifp = m->m_pkthdr.rcvif; 698 if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) { 699 IF_ADDR_LOCK(ifp); 700 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 701 if (ifa->ifa_addr->sa_family != AF_INET) 702 continue; 703 ia = ifatoia(ifa); 704 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 705 t.s_addr) { 706 t = IA_SIN(ia)->sin_addr; 707 IF_ADDR_UNLOCK(ifp); 708 goto match; 709 } 710 } 711 IF_ADDR_UNLOCK(ifp); 712 } 713 /* 714 * If the packet was transiting through us, use the address of 715 * the interface the packet came through in. If that interface 716 * doesn't have a suitable IP address, the normal selection 717 * criteria apply. 718 */ 719 if (V_icmp_rfi && ifp != NULL) { 720 IF_ADDR_LOCK(ifp); 721 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 722 if (ifa->ifa_addr->sa_family != AF_INET) 723 continue; 724 ia = ifatoia(ifa); 725 t = IA_SIN(ia)->sin_addr; 726 IF_ADDR_UNLOCK(ifp); 727 goto match; 728 } 729 IF_ADDR_UNLOCK(ifp); 730 } 731 /* 732 * If the incoming packet was not addressed directly to us, use 733 * designated interface for icmp replies specified by sysctl 734 * net.inet.icmp.reply_src (default not set). Otherwise continue 735 * with normal source selection. 736 */ 737 if (V_reply_src[0] != '\0' && (ifp = ifunit(V_reply_src))) { 738 IF_ADDR_LOCK(ifp); 739 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 740 if (ifa->ifa_addr->sa_family != AF_INET) 741 continue; 742 ia = ifatoia(ifa); 743 t = IA_SIN(ia)->sin_addr; 744 IF_ADDR_UNLOCK(ifp); 745 goto match; 746 } 747 IF_ADDR_UNLOCK(ifp); 748 } 749 /* 750 * If the packet was transiting through us, use the address of 751 * the interface that is the closest to the packet source. 752 * When we don't have a route back to the packet source, stop here 753 * and drop the packet. 754 */ 755 ia = ip_rtaddr(ip->ip_dst, M_GETFIB(m)); 756 if (ia == NULL) { 757 m_freem(m); 758 ICMPSTAT_INC(icps_noroute); 759 goto done; 760 } 761 t = IA_SIN(ia)->sin_addr; 762 ifa_free(&ia->ia_ifa); 763 match: 764 #ifdef MAC 765 mac_netinet_icmp_replyinplace(m); 766 #endif 767 ip->ip_src = t; 768 ip->ip_ttl = V_ip_defttl; 769 770 if (optlen > 0) { 771 register u_char *cp; 772 int opt, cnt; 773 u_int len; 774 775 /* 776 * Retrieve any source routing from the incoming packet; 777 * add on any record-route or timestamp options. 778 */ 779 cp = (u_char *) (ip + 1); 780 if ((opts = ip_srcroute(m)) == 0 && 781 (opts = m_gethdr(M_DONTWAIT, MT_DATA))) { 782 opts->m_len = sizeof(struct in_addr); 783 mtod(opts, struct in_addr *)->s_addr = 0; 784 } 785 if (opts) { 786 #ifdef ICMPPRINTFS 787 if (icmpprintfs) 788 printf("icmp_reflect optlen %d rt %d => ", 789 optlen, opts->m_len); 790 #endif 791 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { 792 opt = cp[IPOPT_OPTVAL]; 793 if (opt == IPOPT_EOL) 794 break; 795 if (opt == IPOPT_NOP) 796 len = 1; 797 else { 798 if (cnt < IPOPT_OLEN + sizeof(*cp)) 799 break; 800 len = cp[IPOPT_OLEN]; 801 if (len < IPOPT_OLEN + sizeof(*cp) || 802 len > cnt) 803 break; 804 } 805 /* 806 * Should check for overflow, but it "can't happen" 807 */ 808 if (opt == IPOPT_RR || opt == IPOPT_TS || 809 opt == IPOPT_SECURITY) { 810 bcopy((caddr_t)cp, 811 mtod(opts, caddr_t) + opts->m_len, len); 812 opts->m_len += len; 813 } 814 } 815 /* Terminate & pad, if necessary */ 816 cnt = opts->m_len % 4; 817 if (cnt) { 818 for (; cnt < 4; cnt++) { 819 *(mtod(opts, caddr_t) + opts->m_len) = 820 IPOPT_EOL; 821 opts->m_len++; 822 } 823 } 824 #ifdef ICMPPRINTFS 825 if (icmpprintfs) 826 printf("%d\n", opts->m_len); 827 #endif 828 } 829 /* 830 * Now strip out original options by copying rest of first 831 * mbuf's data back, and adjust the IP length. 832 */ 833 ip->ip_len -= optlen; 834 ip->ip_v = IPVERSION; 835 ip->ip_hl = 5; 836 m->m_len -= optlen; 837 if (m->m_flags & M_PKTHDR) 838 m->m_pkthdr.len -= optlen; 839 optlen += sizeof(struct ip); 840 bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1), 841 (unsigned)(m->m_len - sizeof(struct ip))); 842 } 843 m_tag_delete_nonpersistent(m); 844 m->m_flags &= ~(M_BCAST|M_MCAST); 845 icmp_send(m, opts); 846 done: 847 if (opts) 848 (void)m_free(opts); 849 } 850 851 /* 852 * Send an icmp packet back to the ip level, 853 * after supplying a checksum. 854 */ 855 static void 856 icmp_send(struct mbuf *m, struct mbuf *opts) 857 { 858 register struct ip *ip = mtod(m, struct ip *); 859 register int hlen; 860 register struct icmp *icp; 861 862 hlen = ip->ip_hl << 2; 863 m->m_data += hlen; 864 m->m_len -= hlen; 865 icp = mtod(m, struct icmp *); 866 icp->icmp_cksum = 0; 867 icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen); 868 m->m_data -= hlen; 869 m->m_len += hlen; 870 m->m_pkthdr.rcvif = (struct ifnet *)0; 871 #ifdef ICMPPRINTFS 872 if (icmpprintfs) { 873 char buf[4 * sizeof "123"]; 874 strcpy(buf, inet_ntoa(ip->ip_dst)); 875 printf("icmp_send dst %s src %s\n", 876 buf, inet_ntoa(ip->ip_src)); 877 } 878 #endif 879 (void) ip_output(m, opts, NULL, 0, NULL, NULL); 880 } 881 882 /* 883 * Return milliseconds since 00:00 GMT in network format. 884 */ 885 uint32_t 886 iptime(void) 887 { 888 struct timeval atv; 889 u_long t; 890 891 getmicrotime(&atv); 892 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; 893 return (htonl(t)); 894 } 895 896 /* 897 * Return the next larger or smaller MTU plateau (table from RFC 1191) 898 * given current value MTU. If DIR is less than zero, a larger plateau 899 * is returned; otherwise, a smaller value is returned. 900 */ 901 int 902 ip_next_mtu(int mtu, int dir) 903 { 904 static int mtutab[] = { 905 65535, 32000, 17914, 8166, 4352, 2002, 1492, 1280, 1006, 508, 906 296, 68, 0 907 }; 908 int i, size; 909 910 size = (sizeof mtutab) / (sizeof mtutab[0]); 911 if (dir >= 0) { 912 for (i = 0; i < size; i++) 913 if (mtu > mtutab[i]) 914 return mtutab[i]; 915 } else { 916 for (i = size - 1; i >= 0; i--) 917 if (mtu < mtutab[i]) 918 return mtutab[i]; 919 if (mtu == mtutab[0]) 920 return mtutab[0]; 921 } 922 return 0; 923 } 924 925 926 /* 927 * badport_bandlim() - check for ICMP bandwidth limit 928 * 929 * Return 0 if it is ok to send an ICMP error response, -1 if we have 930 * hit our bandwidth limit and it is not ok. 931 * 932 * If icmplim is <= 0, the feature is disabled and 0 is returned. 933 * 934 * For now we separate the TCP and UDP subsystems w/ different 'which' 935 * values. We may eventually remove this separation (and simplify the 936 * code further). 937 * 938 * Note that the printing of the error message is delayed so we can 939 * properly print the icmp error rate that the system was trying to do 940 * (i.e. 22000/100 pps, etc...). This can cause long delays in printing 941 * the 'final' error, but it doesn't make sense to solve the printing 942 * delay with more complex code. 943 */ 944 945 int 946 badport_bandlim(int which) 947 { 948 949 #define N(a) (sizeof (a) / sizeof (a[0])) 950 static struct rate { 951 const char *type; 952 struct timeval lasttime; 953 int curpps; 954 } rates[BANDLIM_MAX+1] = { 955 { "icmp unreach response" }, 956 { "icmp ping response" }, 957 { "icmp tstamp response" }, 958 { "closed port RST response" }, 959 { "open port RST response" }, 960 { "icmp6 unreach response" } 961 }; 962 963 /* 964 * Return ok status if feature disabled or argument out of range. 965 */ 966 if (V_icmplim > 0 && (u_int) which < N(rates)) { 967 struct rate *r = &rates[which]; 968 int opps = r->curpps; 969 970 if (!ppsratecheck(&r->lasttime, &r->curpps, V_icmplim)) 971 return -1; /* discard packet */ 972 /* 973 * If we've dropped below the threshold after having 974 * rate-limited traffic print the message. This preserves 975 * the previous behaviour at the expense of added complexity. 976 */ 977 if (V_icmplim_output && opps > V_icmplim) 978 printf("Limiting %s from %d to %d packets/sec\n", 979 r->type, opps, V_icmplim); 980 } 981 return 0; /* okay to send packet */ 982 #undef N 983 }
Cache object: 8380ab13170284d040ecb6ec34edc6b7
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