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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/9.2/sys/netinet/ip_icmp.c 242640 2012-11-06 00:49:52Z melifaro $"); 34 35 #include "opt_inet.h" 36 #include "opt_ipsec.h" 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/mbuf.h> 41 #include <sys/protosw.h> 42 #include <sys/socket.h> 43 #include <sys/time.h> 44 #include <sys/kernel.h> 45 #include <sys/sysctl.h> 46 #include <sys/syslog.h> 47 48 #include <net/if.h> 49 #include <net/if_types.h> 50 #include <net/route.h> 51 #include <net/vnet.h> 52 53 #include <netinet/in.h> 54 #include <netinet/in_pcb.h> 55 #include <netinet/in_systm.h> 56 #include <netinet/in_var.h> 57 #include <netinet/ip.h> 58 #include <netinet/ip_icmp.h> 59 #include <netinet/ip_var.h> 60 #include <netinet/ip_options.h> 61 #include <netinet/tcp.h> 62 #include <netinet/tcp_var.h> 63 #include <netinet/tcpip.h> 64 #include <netinet/icmp_var.h> 65 66 #ifdef INET 67 #ifdef IPSEC 68 #include <netipsec/ipsec.h> 69 #include <netipsec/key.h> 70 #endif 71 72 #include <machine/in_cksum.h> 73 74 #include <security/mac/mac_framework.h> 75 #endif /* INET */ 76 77 /* 78 * ICMP routines: error generation, receive packet processing, and 79 * routines to turnaround packets back to the originator, and 80 * host table maintenance routines. 81 */ 82 static VNET_DEFINE(int, icmplim) = 200; 83 #define V_icmplim VNET(icmplim) 84 SYSCTL_VNET_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_RW, 85 &VNET_NAME(icmplim), 0, 86 "Maximum number of ICMP responses per second"); 87 88 static VNET_DEFINE(int, icmplim_output) = 1; 89 #define V_icmplim_output VNET(icmplim_output) 90 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, icmplim_output, CTLFLAG_RW, 91 &VNET_NAME(icmplim_output), 0, 92 "Enable rate limiting of ICMP responses"); 93 94 #ifdef INET 95 VNET_DEFINE(struct icmpstat, icmpstat); 96 SYSCTL_VNET_STRUCT(_net_inet_icmp, ICMPCTL_STATS, stats, CTLFLAG_RW, 97 &VNET_NAME(icmpstat), icmpstat, ""); 98 99 static VNET_DEFINE(int, icmpmaskrepl) = 0; 100 #define V_icmpmaskrepl VNET(icmpmaskrepl) 101 SYSCTL_VNET_INT(_net_inet_icmp, ICMPCTL_MASKREPL, maskrepl, CTLFLAG_RW, 102 &VNET_NAME(icmpmaskrepl), 0, 103 "Reply to ICMP Address Mask Request packets."); 104 105 static VNET_DEFINE(u_int, icmpmaskfake) = 0; 106 #define V_icmpmaskfake VNET(icmpmaskfake) 107 SYSCTL_VNET_UINT(_net_inet_icmp, OID_AUTO, maskfake, CTLFLAG_RW, 108 &VNET_NAME(icmpmaskfake), 0, 109 "Fake reply to ICMP Address Mask Request packets."); 110 111 VNET_DEFINE(int, drop_redirect) = 0; 112 113 static VNET_DEFINE(int, log_redirect) = 0; 114 #define V_log_redirect VNET(log_redirect) 115 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, log_redirect, CTLFLAG_RW, 116 &VNET_NAME(log_redirect), 0, 117 "Log ICMP redirects to the console"); 118 119 static VNET_DEFINE(char, reply_src[IFNAMSIZ]); 120 #define V_reply_src VNET(reply_src) 121 SYSCTL_VNET_STRING(_net_inet_icmp, OID_AUTO, reply_src, CTLFLAG_RW, 122 &VNET_NAME(reply_src), IFNAMSIZ, 123 "icmp reply source for non-local packets."); 124 125 static VNET_DEFINE(int, icmp_rfi) = 0; 126 #define V_icmp_rfi VNET(icmp_rfi) 127 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, reply_from_interface, CTLFLAG_RW, 128 &VNET_NAME(icmp_rfi), 0, 129 "ICMP reply from incoming interface for non-local packets"); 130 131 static VNET_DEFINE(int, icmp_quotelen) = 8; 132 #define V_icmp_quotelen VNET(icmp_quotelen) 133 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, quotelen, CTLFLAG_RW, 134 &VNET_NAME(icmp_quotelen), 0, 135 "Number of bytes from original packet to quote in ICMP reply"); 136 137 /* 138 * ICMP broadcast echo sysctl 139 */ 140 static VNET_DEFINE(int, icmpbmcastecho) = 0; 141 #define V_icmpbmcastecho VNET(icmpbmcastecho) 142 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_RW, 143 &VNET_NAME(icmpbmcastecho), 0, 144 ""); 145 146 147 #ifdef ICMPPRINTFS 148 int icmpprintfs = 0; 149 #endif 150 151 static void icmp_reflect(struct mbuf *); 152 static void icmp_send(struct mbuf *, struct mbuf *); 153 154 extern struct protosw inetsw[]; 155 156 static int 157 sysctl_net_icmp_drop_redir(SYSCTL_HANDLER_ARGS) 158 { 159 int error, new; 160 int i; 161 struct radix_node_head *rnh; 162 163 new = V_drop_redirect; 164 error = sysctl_handle_int(oidp, &new, 0, req); 165 if (error == 0 && req->newptr) { 166 new = (new != 0) ? 1 : 0; 167 168 if (new == V_drop_redirect) 169 return (0); 170 171 for (i = 0; i < rt_numfibs; i++) { 172 if ((rnh = rt_tables_get_rnh(i, AF_INET)) == NULL) 173 continue; 174 RADIX_NODE_HEAD_LOCK(rnh); 175 in_setmatchfunc(rnh, new); 176 RADIX_NODE_HEAD_UNLOCK(rnh); 177 } 178 179 V_drop_redirect = new; 180 } 181 182 return (error); 183 } 184 185 SYSCTL_VNET_PROC(_net_inet_icmp, OID_AUTO, drop_redirect, 186 CTLTYPE_INT|CTLFLAG_RW, 0, 0, 187 sysctl_net_icmp_drop_redir, "I", "Ignore ICMP redirects"); 188 189 /* 190 * Kernel module interface for updating icmpstat. The argument is an index 191 * into icmpstat treated as an array of u_long. While this encodes the 192 * general layout of icmpstat into the caller, it doesn't encode its 193 * location, so that future changes to add, for example, per-CPU stats 194 * support won't cause binary compatibility problems for kernel modules. 195 */ 196 void 197 kmod_icmpstat_inc(int statnum) 198 { 199 200 (*((u_long *)&V_icmpstat + statnum))++; 201 } 202 203 /* 204 * Generate an error packet of type error 205 * in response to bad packet ip. 206 */ 207 void 208 icmp_error(struct mbuf *n, int type, int code, uint32_t dest, int mtu) 209 { 210 register struct ip *oip = mtod(n, struct ip *), *nip; 211 register unsigned oiphlen = oip->ip_hl << 2; 212 register struct icmp *icp; 213 register struct mbuf *m; 214 unsigned icmplen, icmpelen, nlen; 215 216 KASSERT((u_int)type <= ICMP_MAXTYPE, ("%s: illegal ICMP type", __func__)); 217 #ifdef ICMPPRINTFS 218 if (icmpprintfs) 219 printf("icmp_error(%p, %x, %d)\n", oip, type, code); 220 #endif 221 if (type != ICMP_REDIRECT) 222 ICMPSTAT_INC(icps_error); 223 /* 224 * Don't send error: 225 * if the original packet was encrypted. 226 * if not the first fragment of message. 227 * in response to a multicast or broadcast packet. 228 * if the old packet protocol was an ICMP error message. 229 */ 230 if (n->m_flags & M_DECRYPTED) 231 goto freeit; 232 if (oip->ip_off & ~(IP_MF|IP_DF)) 233 goto freeit; 234 if (n->m_flags & (M_BCAST|M_MCAST)) 235 goto freeit; 236 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && 237 n->m_len >= oiphlen + ICMP_MINLEN && 238 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiphlen))->icmp_type)) { 239 ICMPSTAT_INC(icps_oldicmp); 240 goto freeit; 241 } 242 /* Drop if IP header plus 8 bytes is not contignous in first mbuf. */ 243 if (oiphlen + 8 > n->m_len) 244 goto freeit; 245 /* 246 * Calculate length to quote from original packet and 247 * prevent the ICMP mbuf from overflowing. 248 * Unfortunatly this is non-trivial since ip_forward() 249 * sends us truncated packets. 250 */ 251 nlen = m_length(n, NULL); 252 if (oip->ip_p == IPPROTO_TCP) { 253 struct tcphdr *th; 254 int tcphlen; 255 256 if (oiphlen + sizeof(struct tcphdr) > n->m_len && 257 n->m_next == NULL) 258 goto stdreply; 259 if (n->m_len < oiphlen + sizeof(struct tcphdr) && 260 ((n = m_pullup(n, oiphlen + sizeof(struct tcphdr))) == NULL)) 261 goto freeit; 262 th = (struct tcphdr *)((caddr_t)oip + oiphlen); 263 tcphlen = th->th_off << 2; 264 if (tcphlen < sizeof(struct tcphdr)) 265 goto freeit; 266 if (oip->ip_len < oiphlen + tcphlen) 267 goto freeit; 268 if (oiphlen + tcphlen > n->m_len && n->m_next == NULL) 269 goto stdreply; 270 if (n->m_len < oiphlen + tcphlen && 271 ((n = m_pullup(n, oiphlen + tcphlen)) == NULL)) 272 goto freeit; 273 icmpelen = max(tcphlen, min(V_icmp_quotelen, oip->ip_len - oiphlen)); 274 } else 275 stdreply: icmpelen = max(8, min(V_icmp_quotelen, oip->ip_len - oiphlen)); 276 277 icmplen = min(oiphlen + icmpelen, nlen); 278 if (icmplen < sizeof(struct ip)) 279 goto freeit; 280 281 if (MHLEN > sizeof(struct ip) + ICMP_MINLEN + icmplen) 282 m = m_gethdr(M_DONTWAIT, MT_DATA); 283 else 284 m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR); 285 if (m == NULL) 286 goto freeit; 287 #ifdef MAC 288 mac_netinet_icmp_reply(n, m); 289 #endif 290 icmplen = min(icmplen, M_TRAILINGSPACE(m) - sizeof(struct ip) - ICMP_MINLEN); 291 m_align(m, ICMP_MINLEN + icmplen); 292 m->m_len = ICMP_MINLEN + icmplen; 293 294 /* XXX MRT make the outgoing packet use the same FIB 295 * that was associated with the incoming packet 296 */ 297 M_SETFIB(m, M_GETFIB(n)); 298 icp = mtod(m, struct icmp *); 299 ICMPSTAT_INC(icps_outhist[type]); 300 icp->icmp_type = type; 301 if (type == ICMP_REDIRECT) 302 icp->icmp_gwaddr.s_addr = dest; 303 else { 304 icp->icmp_void = 0; 305 /* 306 * The following assignments assume an overlay with the 307 * just zeroed icmp_void field. 308 */ 309 if (type == ICMP_PARAMPROB) { 310 icp->icmp_pptr = code; 311 code = 0; 312 } else if (type == ICMP_UNREACH && 313 code == ICMP_UNREACH_NEEDFRAG && mtu) { 314 icp->icmp_nextmtu = htons(mtu); 315 } 316 } 317 icp->icmp_code = code; 318 319 /* 320 * Copy the quotation into ICMP message and 321 * convert quoted IP header back to network representation. 322 */ 323 m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip); 324 nip = &icp->icmp_ip; 325 nip->ip_len = htons(nip->ip_len); 326 nip->ip_off = htons(nip->ip_off); 327 328 /* 329 * Set up ICMP message mbuf and copy old IP header (without options 330 * in front of ICMP message. 331 * If the original mbuf was meant to bypass the firewall, the error 332 * reply should bypass as well. 333 */ 334 m->m_flags |= n->m_flags & M_SKIP_FIREWALL; 335 m->m_data -= sizeof(struct ip); 336 m->m_len += sizeof(struct ip); 337 m->m_pkthdr.len = m->m_len; 338 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif; 339 nip = mtod(m, struct ip *); 340 bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip)); 341 nip->ip_len = m->m_len; 342 nip->ip_v = IPVERSION; 343 nip->ip_hl = 5; 344 nip->ip_p = IPPROTO_ICMP; 345 nip->ip_tos = 0; 346 icmp_reflect(m); 347 348 freeit: 349 m_freem(n); 350 } 351 352 /* 353 * Process a received ICMP message. 354 */ 355 void 356 icmp_input(struct mbuf *m, int off) 357 { 358 struct icmp *icp; 359 struct in_ifaddr *ia; 360 struct ip *ip = mtod(m, struct ip *); 361 struct sockaddr_in icmpsrc, icmpdst, icmpgw; 362 int hlen = off; 363 int icmplen = ip->ip_len; 364 int i, code; 365 void (*ctlfunc)(int, struct sockaddr *, void *); 366 int fibnum; 367 368 /* 369 * Locate icmp structure in mbuf, and check 370 * that not corrupted and of at least minimum length. 371 */ 372 #ifdef ICMPPRINTFS 373 if (icmpprintfs) { 374 char buf[4 * sizeof "123"]; 375 strcpy(buf, inet_ntoa(ip->ip_src)); 376 printf("icmp_input from %s to %s, len %d\n", 377 buf, inet_ntoa(ip->ip_dst), icmplen); 378 } 379 #endif 380 if (icmplen < ICMP_MINLEN) { 381 ICMPSTAT_INC(icps_tooshort); 382 goto freeit; 383 } 384 i = hlen + min(icmplen, ICMP_ADVLENMIN); 385 if (m->m_len < i && (m = m_pullup(m, i)) == NULL) { 386 ICMPSTAT_INC(icps_tooshort); 387 return; 388 } 389 ip = mtod(m, struct ip *); 390 m->m_len -= hlen; 391 m->m_data += hlen; 392 icp = mtod(m, struct icmp *); 393 if (in_cksum(m, icmplen)) { 394 ICMPSTAT_INC(icps_checksum); 395 goto freeit; 396 } 397 m->m_len += hlen; 398 m->m_data -= hlen; 399 400 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 401 /* 402 * Deliver very specific ICMP type only. 403 */ 404 switch (icp->icmp_type) { 405 case ICMP_UNREACH: 406 case ICMP_TIMXCEED: 407 break; 408 default: 409 goto freeit; 410 } 411 } 412 413 #ifdef ICMPPRINTFS 414 if (icmpprintfs) 415 printf("icmp_input, type %d code %d\n", icp->icmp_type, 416 icp->icmp_code); 417 #endif 418 419 /* 420 * Message type specific processing. 421 */ 422 if (icp->icmp_type > ICMP_MAXTYPE) 423 goto raw; 424 425 /* Initialize */ 426 bzero(&icmpsrc, sizeof(icmpsrc)); 427 icmpsrc.sin_len = sizeof(struct sockaddr_in); 428 icmpsrc.sin_family = AF_INET; 429 bzero(&icmpdst, sizeof(icmpdst)); 430 icmpdst.sin_len = sizeof(struct sockaddr_in); 431 icmpdst.sin_family = AF_INET; 432 bzero(&icmpgw, sizeof(icmpgw)); 433 icmpgw.sin_len = sizeof(struct sockaddr_in); 434 icmpgw.sin_family = AF_INET; 435 436 ICMPSTAT_INC(icps_inhist[icp->icmp_type]); 437 code = icp->icmp_code; 438 switch (icp->icmp_type) { 439 440 case ICMP_UNREACH: 441 switch (code) { 442 case ICMP_UNREACH_NET: 443 case ICMP_UNREACH_HOST: 444 case ICMP_UNREACH_SRCFAIL: 445 case ICMP_UNREACH_NET_UNKNOWN: 446 case ICMP_UNREACH_HOST_UNKNOWN: 447 case ICMP_UNREACH_ISOLATED: 448 case ICMP_UNREACH_TOSNET: 449 case ICMP_UNREACH_TOSHOST: 450 case ICMP_UNREACH_HOST_PRECEDENCE: 451 case ICMP_UNREACH_PRECEDENCE_CUTOFF: 452 code = PRC_UNREACH_NET; 453 break; 454 455 case ICMP_UNREACH_NEEDFRAG: 456 code = PRC_MSGSIZE; 457 break; 458 459 /* 460 * RFC 1122, Sections 3.2.2.1 and 4.2.3.9. 461 * Treat subcodes 2,3 as immediate RST 462 */ 463 case ICMP_UNREACH_PROTOCOL: 464 case ICMP_UNREACH_PORT: 465 code = PRC_UNREACH_PORT; 466 break; 467 468 case ICMP_UNREACH_NET_PROHIB: 469 case ICMP_UNREACH_HOST_PROHIB: 470 case ICMP_UNREACH_FILTER_PROHIB: 471 code = PRC_UNREACH_ADMIN_PROHIB; 472 break; 473 474 default: 475 goto badcode; 476 } 477 goto deliver; 478 479 case ICMP_TIMXCEED: 480 if (code > 1) 481 goto badcode; 482 code += PRC_TIMXCEED_INTRANS; 483 goto deliver; 484 485 case ICMP_PARAMPROB: 486 if (code > 1) 487 goto badcode; 488 code = PRC_PARAMPROB; 489 goto deliver; 490 491 case ICMP_SOURCEQUENCH: 492 if (code) 493 goto badcode; 494 code = PRC_QUENCH; 495 deliver: 496 /* 497 * Problem with datagram; advise higher level routines. 498 */ 499 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 500 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 501 ICMPSTAT_INC(icps_badlen); 502 goto freeit; 503 } 504 icp->icmp_ip.ip_len = ntohs(icp->icmp_ip.ip_len); 505 /* Discard ICMP's in response to multicast packets */ 506 if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr))) 507 goto badcode; 508 #ifdef ICMPPRINTFS 509 if (icmpprintfs) 510 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p); 511 #endif 512 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 513 /* 514 * XXX if the packet contains [IPv4 AH TCP], we can't make a 515 * notification to TCP layer. 516 */ 517 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput; 518 if (ctlfunc) 519 (*ctlfunc)(code, (struct sockaddr *)&icmpsrc, 520 (void *)&icp->icmp_ip); 521 break; 522 523 badcode: 524 ICMPSTAT_INC(icps_badcode); 525 break; 526 527 case ICMP_ECHO: 528 if (!V_icmpbmcastecho 529 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) { 530 ICMPSTAT_INC(icps_bmcastecho); 531 break; 532 } 533 icp->icmp_type = ICMP_ECHOREPLY; 534 if (badport_bandlim(BANDLIM_ICMP_ECHO) < 0) 535 goto freeit; 536 else 537 goto reflect; 538 539 case ICMP_TSTAMP: 540 if (!V_icmpbmcastecho 541 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) { 542 ICMPSTAT_INC(icps_bmcasttstamp); 543 break; 544 } 545 if (icmplen < ICMP_TSLEN) { 546 ICMPSTAT_INC(icps_badlen); 547 break; 548 } 549 icp->icmp_type = ICMP_TSTAMPREPLY; 550 icp->icmp_rtime = iptime(); 551 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ 552 if (badport_bandlim(BANDLIM_ICMP_TSTAMP) < 0) 553 goto freeit; 554 else 555 goto reflect; 556 557 case ICMP_MASKREQ: 558 if (V_icmpmaskrepl == 0) 559 break; 560 /* 561 * We are not able to respond with all ones broadcast 562 * unless we receive it over a point-to-point interface. 563 */ 564 if (icmplen < ICMP_MASKLEN) 565 break; 566 switch (ip->ip_dst.s_addr) { 567 568 case INADDR_BROADCAST: 569 case INADDR_ANY: 570 icmpdst.sin_addr = ip->ip_src; 571 break; 572 573 default: 574 icmpdst.sin_addr = ip->ip_dst; 575 } 576 ia = (struct in_ifaddr *)ifaof_ifpforaddr( 577 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif); 578 if (ia == NULL) 579 break; 580 if (ia->ia_ifp == NULL) { 581 ifa_free(&ia->ia_ifa); 582 break; 583 } 584 icp->icmp_type = ICMP_MASKREPLY; 585 if (V_icmpmaskfake == 0) 586 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; 587 else 588 icp->icmp_mask = V_icmpmaskfake; 589 if (ip->ip_src.s_addr == 0) { 590 if (ia->ia_ifp->if_flags & IFF_BROADCAST) 591 ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr; 592 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) 593 ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr; 594 } 595 ifa_free(&ia->ia_ifa); 596 reflect: 597 ip->ip_len += hlen; /* since ip_input deducts this */ 598 ICMPSTAT_INC(icps_reflect); 599 ICMPSTAT_INC(icps_outhist[icp->icmp_type]); 600 icmp_reflect(m); 601 return; 602 603 case ICMP_REDIRECT: 604 if (V_log_redirect) { 605 u_long src, dst, gw; 606 607 src = ntohl(ip->ip_src.s_addr); 608 dst = ntohl(icp->icmp_ip.ip_dst.s_addr); 609 gw = ntohl(icp->icmp_gwaddr.s_addr); 610 printf("icmp redirect from %d.%d.%d.%d: " 611 "%d.%d.%d.%d => %d.%d.%d.%d\n", 612 (int)(src >> 24), (int)((src >> 16) & 0xff), 613 (int)((src >> 8) & 0xff), (int)(src & 0xff), 614 (int)(dst >> 24), (int)((dst >> 16) & 0xff), 615 (int)((dst >> 8) & 0xff), (int)(dst & 0xff), 616 (int)(gw >> 24), (int)((gw >> 16) & 0xff), 617 (int)((gw >> 8) & 0xff), (int)(gw & 0xff)); 618 } 619 /* 620 * RFC1812 says we must ignore ICMP redirects if we 621 * are acting as router. 622 */ 623 if (V_drop_redirect || V_ipforwarding) 624 break; 625 if (code > 3) 626 goto badcode; 627 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 628 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 629 ICMPSTAT_INC(icps_badlen); 630 break; 631 } 632 /* 633 * Short circuit routing redirects to force 634 * immediate change in the kernel's routing 635 * tables. The message is also handed to anyone 636 * listening on a raw socket (e.g. the routing 637 * daemon for use in updating its tables). 638 */ 639 icmpgw.sin_addr = ip->ip_src; 640 icmpdst.sin_addr = icp->icmp_gwaddr; 641 #ifdef ICMPPRINTFS 642 if (icmpprintfs) { 643 char buf[4 * sizeof "123"]; 644 strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst)); 645 646 printf("redirect dst %s to %s\n", 647 buf, inet_ntoa(icp->icmp_gwaddr)); 648 } 649 #endif 650 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 651 for ( fibnum = 0; fibnum < rt_numfibs; fibnum++) { 652 in_rtredirect((struct sockaddr *)&icmpsrc, 653 (struct sockaddr *)&icmpdst, 654 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST, 655 (struct sockaddr *)&icmpgw, fibnum); 656 } 657 pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc); 658 #ifdef IPSEC 659 key_sa_routechange((struct sockaddr *)&icmpsrc); 660 #endif 661 break; 662 663 /* 664 * No kernel processing for the following; 665 * just fall through to send to raw listener. 666 */ 667 case ICMP_ECHOREPLY: 668 case ICMP_ROUTERADVERT: 669 case ICMP_ROUTERSOLICIT: 670 case ICMP_TSTAMPREPLY: 671 case ICMP_IREQREPLY: 672 case ICMP_MASKREPLY: 673 default: 674 break; 675 } 676 677 raw: 678 rip_input(m, off); 679 return; 680 681 freeit: 682 m_freem(m); 683 } 684 685 /* 686 * Reflect the ip packet back to the source 687 */ 688 static void 689 icmp_reflect(struct mbuf *m) 690 { 691 struct ip *ip = mtod(m, struct ip *); 692 struct ifaddr *ifa; 693 struct ifnet *ifp; 694 struct in_ifaddr *ia; 695 struct in_addr t; 696 struct mbuf *opts = 0; 697 int optlen = (ip->ip_hl << 2) - sizeof(struct ip); 698 699 if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)) || 700 IN_EXPERIMENTAL(ntohl(ip->ip_src.s_addr)) || 701 IN_ZERONET(ntohl(ip->ip_src.s_addr)) ) { 702 m_freem(m); /* Bad return address */ 703 ICMPSTAT_INC(icps_badaddr); 704 goto done; /* Ip_output() will check for broadcast */ 705 } 706 707 m_addr_changed(m); 708 709 t = ip->ip_dst; 710 ip->ip_dst = ip->ip_src; 711 712 /* 713 * Source selection for ICMP replies: 714 * 715 * If the incoming packet was addressed directly to one of our 716 * own addresses, use dst as the src for the reply. 717 */ 718 IN_IFADDR_RLOCK(); 719 LIST_FOREACH(ia, INADDR_HASH(t.s_addr), ia_hash) { 720 if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr) { 721 t = IA_SIN(ia)->sin_addr; 722 IN_IFADDR_RUNLOCK(); 723 goto match; 724 } 725 } 726 IN_IFADDR_RUNLOCK(); 727 728 /* 729 * If the incoming packet was addressed to one of our broadcast 730 * addresses, use the first non-broadcast address which corresponds 731 * to the incoming interface. 732 */ 733 ifp = m->m_pkthdr.rcvif; 734 if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) { 735 IF_ADDR_RLOCK(ifp); 736 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 737 if (ifa->ifa_addr->sa_family != AF_INET) 738 continue; 739 ia = ifatoia(ifa); 740 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 741 t.s_addr) { 742 t = IA_SIN(ia)->sin_addr; 743 IF_ADDR_RUNLOCK(ifp); 744 goto match; 745 } 746 } 747 IF_ADDR_RUNLOCK(ifp); 748 } 749 /* 750 * If the packet was transiting through us, use the address of 751 * the interface the packet came through in. If that interface 752 * doesn't have a suitable IP address, the normal selection 753 * criteria apply. 754 */ 755 if (V_icmp_rfi && ifp != NULL) { 756 IF_ADDR_RLOCK(ifp); 757 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 758 if (ifa->ifa_addr->sa_family != AF_INET) 759 continue; 760 ia = ifatoia(ifa); 761 t = IA_SIN(ia)->sin_addr; 762 IF_ADDR_RUNLOCK(ifp); 763 goto match; 764 } 765 IF_ADDR_RUNLOCK(ifp); 766 } 767 /* 768 * If the incoming packet was not addressed directly to us, use 769 * designated interface for icmp replies specified by sysctl 770 * net.inet.icmp.reply_src (default not set). Otherwise continue 771 * with normal source selection. 772 */ 773 if (V_reply_src[0] != '\0' && (ifp = ifunit(V_reply_src))) { 774 IF_ADDR_RLOCK(ifp); 775 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 776 if (ifa->ifa_addr->sa_family != AF_INET) 777 continue; 778 ia = ifatoia(ifa); 779 t = IA_SIN(ia)->sin_addr; 780 IF_ADDR_RUNLOCK(ifp); 781 goto match; 782 } 783 IF_ADDR_RUNLOCK(ifp); 784 } 785 /* 786 * If the packet was transiting through us, use the address of 787 * the interface that is the closest to the packet source. 788 * When we don't have a route back to the packet source, stop here 789 * and drop the packet. 790 */ 791 ia = ip_rtaddr(ip->ip_dst, M_GETFIB(m)); 792 if (ia == NULL) { 793 m_freem(m); 794 ICMPSTAT_INC(icps_noroute); 795 goto done; 796 } 797 t = IA_SIN(ia)->sin_addr; 798 ifa_free(&ia->ia_ifa); 799 match: 800 #ifdef MAC 801 mac_netinet_icmp_replyinplace(m); 802 #endif 803 ip->ip_src = t; 804 ip->ip_ttl = V_ip_defttl; 805 806 if (optlen > 0) { 807 register u_char *cp; 808 int opt, cnt; 809 u_int len; 810 811 /* 812 * Retrieve any source routing from the incoming packet; 813 * add on any record-route or timestamp options. 814 */ 815 cp = (u_char *) (ip + 1); 816 if ((opts = ip_srcroute(m)) == 0 && 817 (opts = m_gethdr(M_DONTWAIT, MT_DATA))) { 818 opts->m_len = sizeof(struct in_addr); 819 mtod(opts, struct in_addr *)->s_addr = 0; 820 } 821 if (opts) { 822 #ifdef ICMPPRINTFS 823 if (icmpprintfs) 824 printf("icmp_reflect optlen %d rt %d => ", 825 optlen, opts->m_len); 826 #endif 827 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { 828 opt = cp[IPOPT_OPTVAL]; 829 if (opt == IPOPT_EOL) 830 break; 831 if (opt == IPOPT_NOP) 832 len = 1; 833 else { 834 if (cnt < IPOPT_OLEN + sizeof(*cp)) 835 break; 836 len = cp[IPOPT_OLEN]; 837 if (len < IPOPT_OLEN + sizeof(*cp) || 838 len > cnt) 839 break; 840 } 841 /* 842 * Should check for overflow, but it "can't happen" 843 */ 844 if (opt == IPOPT_RR || opt == IPOPT_TS || 845 opt == IPOPT_SECURITY) { 846 bcopy((caddr_t)cp, 847 mtod(opts, caddr_t) + opts->m_len, len); 848 opts->m_len += len; 849 } 850 } 851 /* Terminate & pad, if necessary */ 852 cnt = opts->m_len % 4; 853 if (cnt) { 854 for (; cnt < 4; cnt++) { 855 *(mtod(opts, caddr_t) + opts->m_len) = 856 IPOPT_EOL; 857 opts->m_len++; 858 } 859 } 860 #ifdef ICMPPRINTFS 861 if (icmpprintfs) 862 printf("%d\n", opts->m_len); 863 #endif 864 } 865 /* 866 * Now strip out original options by copying rest of first 867 * mbuf's data back, and adjust the IP length. 868 */ 869 ip->ip_len -= optlen; 870 ip->ip_v = IPVERSION; 871 ip->ip_hl = 5; 872 m->m_len -= optlen; 873 if (m->m_flags & M_PKTHDR) 874 m->m_pkthdr.len -= optlen; 875 optlen += sizeof(struct ip); 876 bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1), 877 (unsigned)(m->m_len - sizeof(struct ip))); 878 } 879 m_tag_delete_nonpersistent(m); 880 m->m_flags &= ~(M_BCAST|M_MCAST); 881 icmp_send(m, opts); 882 done: 883 if (opts) 884 (void)m_free(opts); 885 } 886 887 /* 888 * Send an icmp packet back to the ip level, 889 * after supplying a checksum. 890 */ 891 static void 892 icmp_send(struct mbuf *m, struct mbuf *opts) 893 { 894 register struct ip *ip = mtod(m, struct ip *); 895 register int hlen; 896 register struct icmp *icp; 897 898 hlen = ip->ip_hl << 2; 899 m->m_data += hlen; 900 m->m_len -= hlen; 901 icp = mtod(m, struct icmp *); 902 icp->icmp_cksum = 0; 903 icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen); 904 m->m_data -= hlen; 905 m->m_len += hlen; 906 m->m_pkthdr.rcvif = (struct ifnet *)0; 907 #ifdef ICMPPRINTFS 908 if (icmpprintfs) { 909 char buf[4 * sizeof "123"]; 910 strcpy(buf, inet_ntoa(ip->ip_dst)); 911 printf("icmp_send dst %s src %s\n", 912 buf, inet_ntoa(ip->ip_src)); 913 } 914 #endif 915 (void) ip_output(m, opts, NULL, 0, NULL, NULL); 916 } 917 918 /* 919 * Return milliseconds since 00:00 GMT in network format. 920 */ 921 uint32_t 922 iptime(void) 923 { 924 struct timeval atv; 925 u_long t; 926 927 getmicrotime(&atv); 928 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; 929 return (htonl(t)); 930 } 931 932 /* 933 * Return the next larger or smaller MTU plateau (table from RFC 1191) 934 * given current value MTU. If DIR is less than zero, a larger plateau 935 * is returned; otherwise, a smaller value is returned. 936 */ 937 int 938 ip_next_mtu(int mtu, int dir) 939 { 940 static int mtutab[] = { 941 65535, 32000, 17914, 8166, 4352, 2002, 1492, 1280, 1006, 508, 942 296, 68, 0 943 }; 944 int i, size; 945 946 size = (sizeof mtutab) / (sizeof mtutab[0]); 947 if (dir >= 0) { 948 for (i = 0; i < size; i++) 949 if (mtu > mtutab[i]) 950 return mtutab[i]; 951 } else { 952 for (i = size - 1; i >= 0; i--) 953 if (mtu < mtutab[i]) 954 return mtutab[i]; 955 if (mtu == mtutab[0]) 956 return mtutab[0]; 957 } 958 return 0; 959 } 960 #endif /* INET */ 961 962 963 /* 964 * badport_bandlim() - check for ICMP bandwidth limit 965 * 966 * Return 0 if it is ok to send an ICMP error response, -1 if we have 967 * hit our bandwidth limit and it is not ok. 968 * 969 * If icmplim is <= 0, the feature is disabled and 0 is returned. 970 * 971 * For now we separate the TCP and UDP subsystems w/ different 'which' 972 * values. We may eventually remove this separation (and simplify the 973 * code further). 974 * 975 * Note that the printing of the error message is delayed so we can 976 * properly print the icmp error rate that the system was trying to do 977 * (i.e. 22000/100 pps, etc...). This can cause long delays in printing 978 * the 'final' error, but it doesn't make sense to solve the printing 979 * delay with more complex code. 980 */ 981 982 int 983 badport_bandlim(int which) 984 { 985 986 #define N(a) (sizeof (a) / sizeof (a[0])) 987 static struct rate { 988 const char *type; 989 struct timeval lasttime; 990 int curpps; 991 } rates[BANDLIM_MAX+1] = { 992 { "icmp unreach response" }, 993 { "icmp ping response" }, 994 { "icmp tstamp response" }, 995 { "closed port RST response" }, 996 { "open port RST response" }, 997 { "icmp6 unreach response" }, 998 { "sctp ootb response" } 999 }; 1000 1001 /* 1002 * Return ok status if feature disabled or argument out of range. 1003 */ 1004 if (V_icmplim > 0 && (u_int) which < N(rates)) { 1005 struct rate *r = &rates[which]; 1006 int opps = r->curpps; 1007 1008 if (!ppsratecheck(&r->lasttime, &r->curpps, V_icmplim)) 1009 return -1; /* discard packet */ 1010 /* 1011 * If we've dropped below the threshold after having 1012 * rate-limited traffic print the message. This preserves 1013 * the previous behaviour at the expense of added complexity. 1014 */ 1015 if (V_icmplim_output && opps > V_icmplim) 1016 log(LOG_NOTICE, "Limiting %s from %d to %d packets/sec\n", 1017 r->type, opps, V_icmplim); 1018 } 1019 return 0; /* okay to send packet */ 1020 #undef N 1021 }
Cache object: 2d6b5b6f1326b9034cba618152bd4d64
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