Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]
FreeBSD/Linux Kernel Cross Reference
sys/netinet/ip_icmp.c
Version:
- FREEBSD - FREEBSD-13-STABLE - FREEBSD-13-0 - FREEBSD-12-STABLE - FREEBSD-12-0 - FREEBSD-11-STABLE - FREEBSD-11-0 - FREEBSD-10-STABLE - FREEBSD-10-0 - FREEBSD-9-STABLE - FREEBSD-9-0 - FREEBSD-8-STABLE - FREEBSD-8-0 - FREEBSD-7-STABLE - FREEBSD-7-0 - FREEBSD-6-STABLE - FREEBSD-6-0 - FREEBSD-5-STABLE - FREEBSD-5-0 - FREEBSD-4-STABLE - FREEBSD-3-STABLE - FREEBSD22 - l41 - OPENBSD - linux-2.6 - MK84 - PLAN9 - xnu-8792
SearchContext: - none - 3 - 10
SearchContext: - none - 3 - 10
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/11.2/sys/netinet/ip_icmp.c 341089 2018-11-27 19:43:16Z gordon $"); 34 35 #include "opt_inet.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/lock.h> 45 #include <sys/rmlock.h> 46 #include <sys/sysctl.h> 47 #include <sys/syslog.h> 48 49 #include <net/if.h> 50 #include <net/if_var.h> 51 #include <net/if_types.h> 52 #include <net/route.h> 53 #include <net/vnet.h> 54 55 #include <netinet/in.h> 56 #include <netinet/in_fib.h> 57 #include <netinet/in_pcb.h> 58 #include <netinet/in_systm.h> 59 #include <netinet/in_var.h> 60 #include <netinet/ip.h> 61 #include <netinet/ip_icmp.h> 62 #include <netinet/ip_var.h> 63 #include <netinet/ip_options.h> 64 #include <netinet/sctp.h> 65 #include <netinet/tcp.h> 66 #include <netinet/tcp_var.h> 67 #include <netinet/tcpip.h> 68 #include <netinet/icmp_var.h> 69 70 #ifdef INET 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_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_VNET | 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_INT(_net_inet_icmp, OID_AUTO, icmplim_output, CTLFLAG_VNET | CTLFLAG_RW, 91 &VNET_NAME(icmplim_output), 0, 92 "Enable logging of ICMP response rate limiting"); 93 94 #ifdef INET 95 VNET_PCPUSTAT_DEFINE(struct icmpstat, icmpstat); 96 VNET_PCPUSTAT_SYSINIT(icmpstat); 97 SYSCTL_VNET_PCPUSTAT(_net_inet_icmp, ICMPCTL_STATS, stats, struct icmpstat, 98 icmpstat, "ICMP statistics (struct icmpstat, netinet/icmp_var.h)"); 99 100 #ifdef VIMAGE 101 VNET_PCPUSTAT_SYSUNINIT(icmpstat); 102 #endif /* VIMAGE */ 103 104 static VNET_DEFINE(int, icmpmaskrepl) = 0; 105 #define V_icmpmaskrepl VNET(icmpmaskrepl) 106 SYSCTL_INT(_net_inet_icmp, ICMPCTL_MASKREPL, maskrepl, CTLFLAG_VNET | CTLFLAG_RW, 107 &VNET_NAME(icmpmaskrepl), 0, 108 "Reply to ICMP Address Mask Request packets"); 109 110 static VNET_DEFINE(u_int, icmpmaskfake) = 0; 111 #define V_icmpmaskfake VNET(icmpmaskfake) 112 SYSCTL_UINT(_net_inet_icmp, OID_AUTO, maskfake, CTLFLAG_VNET | CTLFLAG_RW, 113 &VNET_NAME(icmpmaskfake), 0, 114 "Fake reply to ICMP Address Mask Request packets"); 115 116 VNET_DEFINE(int, drop_redirect) = 0; 117 #define V_drop_redirect VNET(drop_redirect) 118 SYSCTL_INT(_net_inet_icmp, OID_AUTO, drop_redirect, CTLFLAG_VNET | CTLFLAG_RW, 119 &VNET_NAME(drop_redirect), 0, 120 "Ignore ICMP redirects"); 121 122 static VNET_DEFINE(int, log_redirect) = 0; 123 #define V_log_redirect VNET(log_redirect) 124 SYSCTL_INT(_net_inet_icmp, OID_AUTO, log_redirect, CTLFLAG_VNET | CTLFLAG_RW, 125 &VNET_NAME(log_redirect), 0, 126 "Log ICMP redirects to the console"); 127 128 static VNET_DEFINE(char, reply_src[IFNAMSIZ]); 129 #define V_reply_src VNET(reply_src) 130 SYSCTL_STRING(_net_inet_icmp, OID_AUTO, reply_src, CTLFLAG_VNET | CTLFLAG_RW, 131 &VNET_NAME(reply_src), IFNAMSIZ, 132 "ICMP reply source for non-local packets"); 133 134 static VNET_DEFINE(int, icmp_rfi) = 0; 135 #define V_icmp_rfi VNET(icmp_rfi) 136 SYSCTL_INT(_net_inet_icmp, OID_AUTO, reply_from_interface, CTLFLAG_VNET | CTLFLAG_RW, 137 &VNET_NAME(icmp_rfi), 0, 138 "ICMP reply from incoming interface for non-local packets"); 139 140 static VNET_DEFINE(int, icmp_quotelen) = 8; 141 #define V_icmp_quotelen VNET(icmp_quotelen) 142 SYSCTL_INT(_net_inet_icmp, OID_AUTO, quotelen, CTLFLAG_VNET | CTLFLAG_RW, 143 &VNET_NAME(icmp_quotelen), 0, 144 "Number of bytes from original packet to quote in ICMP reply"); 145 146 static VNET_DEFINE(int, icmpbmcastecho) = 0; 147 #define V_icmpbmcastecho VNET(icmpbmcastecho) 148 SYSCTL_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_VNET | CTLFLAG_RW, 149 &VNET_NAME(icmpbmcastecho), 0, 150 "Reply to multicast ICMP Echo Request and Timestamp packets"); 151 152 static VNET_DEFINE(int, icmptstamprepl) = 1; 153 #define V_icmptstamprepl VNET(icmptstamprepl) 154 SYSCTL_INT(_net_inet_icmp, OID_AUTO, tstamprepl, CTLFLAG_RW, 155 &VNET_NAME(icmptstamprepl), 0, 156 "Respond to ICMP Timestamp packets"); 157 158 #ifdef ICMPPRINTFS 159 int icmpprintfs = 0; 160 #endif 161 162 static void icmp_reflect(struct mbuf *); 163 static void icmp_send(struct mbuf *, struct mbuf *); 164 165 extern struct protosw inetsw[]; 166 167 /* 168 * Kernel module interface for updating icmpstat. The argument is an index 169 * into icmpstat treated as an array of u_long. While this encodes the 170 * general layout of icmpstat into the caller, it doesn't encode its 171 * location, so that future changes to add, for example, per-CPU stats 172 * support won't cause binary compatibility problems for kernel modules. 173 */ 174 void 175 kmod_icmpstat_inc(int statnum) 176 { 177 178 counter_u64_add(VNET(icmpstat)[statnum], 1); 179 } 180 181 /* 182 * Generate an error packet of type error 183 * in response to bad packet ip. 184 */ 185 void 186 icmp_error(struct mbuf *n, int type, int code, uint32_t dest, int mtu) 187 { 188 struct ip *oip, *nip; 189 struct icmp *icp; 190 struct mbuf *m; 191 unsigned icmplen, icmpelen, nlen, oiphlen; 192 193 KASSERT((u_int)type <= ICMP_MAXTYPE, ("%s: illegal ICMP type", 194 __func__)); 195 196 if (type != ICMP_REDIRECT) 197 ICMPSTAT_INC(icps_error); 198 /* 199 * Don't send error: 200 * if the original packet was encrypted. 201 * if not the first fragment of message. 202 * in response to a multicast or broadcast packet. 203 * if the old packet protocol was an ICMP error message. 204 */ 205 if (n->m_flags & M_DECRYPTED) 206 goto freeit; 207 if (n->m_flags & (M_BCAST|M_MCAST)) 208 goto freeit; 209 210 /* Drop if IP header plus 8 bytes is not contiguous in first mbuf. */ 211 if (n->m_len < sizeof(struct ip) + ICMP_MINLEN) 212 goto freeit; 213 oip = mtod(n, struct ip *); 214 oiphlen = oip->ip_hl << 2; 215 if (n->m_len < oiphlen + ICMP_MINLEN) 216 goto freeit; 217 #ifdef ICMPPRINTFS 218 if (icmpprintfs) 219 printf("icmp_error(%p, %x, %d)\n", oip, type, code); 220 #endif 221 if (oip->ip_off & htons(~(IP_MF|IP_DF))) 222 goto freeit; 223 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && 224 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + 225 oiphlen))->icmp_type)) { 226 ICMPSTAT_INC(icps_oldicmp); 227 goto freeit; 228 } 229 /* 230 * Calculate length to quote from original packet and 231 * prevent the ICMP mbuf from overflowing. 232 * Unfortunately this is non-trivial since ip_forward() 233 * sends us truncated packets. 234 */ 235 nlen = m_length(n, NULL); 236 if (oip->ip_p == IPPROTO_TCP) { 237 struct tcphdr *th; 238 int tcphlen; 239 240 if (oiphlen + sizeof(struct tcphdr) > n->m_len && 241 n->m_next == NULL) 242 goto stdreply; 243 if (n->m_len < oiphlen + sizeof(struct tcphdr) && 244 (n = m_pullup(n, oiphlen + sizeof(struct tcphdr))) == NULL) 245 goto freeit; 246 oip = mtod(n, struct ip *); 247 th = mtodo(n, oiphlen); 248 tcphlen = th->th_off << 2; 249 if (tcphlen < sizeof(struct tcphdr)) 250 goto freeit; 251 if (ntohs(oip->ip_len) < oiphlen + tcphlen) 252 goto freeit; 253 if (oiphlen + tcphlen > n->m_len && n->m_next == NULL) 254 goto stdreply; 255 if (n->m_len < oiphlen + tcphlen && 256 (n = m_pullup(n, oiphlen + tcphlen)) == NULL) 257 goto freeit; 258 icmpelen = max(tcphlen, min(V_icmp_quotelen, 259 ntohs(oip->ip_len) - oiphlen)); 260 } else if (oip->ip_p == IPPROTO_SCTP) { 261 struct sctphdr *sh; 262 struct sctp_chunkhdr *ch; 263 264 if (ntohs(oip->ip_len) < oiphlen + sizeof(struct sctphdr)) 265 goto stdreply; 266 if (oiphlen + sizeof(struct sctphdr) > n->m_len && 267 n->m_next == NULL) 268 goto stdreply; 269 if (n->m_len < oiphlen + sizeof(struct sctphdr) && 270 (n = m_pullup(n, oiphlen + sizeof(struct sctphdr))) == NULL) 271 goto freeit; 272 oip = mtod(n, struct ip *); 273 icmpelen = max(sizeof(struct sctphdr), 274 min(V_icmp_quotelen, ntohs(oip->ip_len) - oiphlen)); 275 sh = mtodo(n, oiphlen); 276 if (ntohl(sh->v_tag) == 0 && 277 ntohs(oip->ip_len) >= oiphlen + 278 sizeof(struct sctphdr) + 8 && 279 (n->m_len >= oiphlen + sizeof(struct sctphdr) + 8 || 280 n->m_next != NULL)) { 281 if (n->m_len < oiphlen + sizeof(struct sctphdr) + 8 && 282 (n = m_pullup(n, oiphlen + 283 sizeof(struct sctphdr) + 8)) == NULL) 284 goto freeit; 285 oip = mtod(n, struct ip *); 286 sh = mtodo(n, oiphlen); 287 ch = (struct sctp_chunkhdr *)(sh + 1); 288 if (ch->chunk_type == SCTP_INITIATION) { 289 icmpelen = max(sizeof(struct sctphdr) + 8, 290 min(V_icmp_quotelen, ntohs(oip->ip_len) - 291 oiphlen)); 292 } 293 } 294 } else 295 stdreply: icmpelen = max(8, min(V_icmp_quotelen, ntohs(oip->ip_len) - 296 oiphlen)); 297 298 icmplen = min(oiphlen + icmpelen, nlen); 299 if (icmplen < sizeof(struct ip)) 300 goto freeit; 301 302 if (MHLEN > sizeof(struct ip) + ICMP_MINLEN + icmplen) 303 m = m_gethdr(M_NOWAIT, MT_DATA); 304 else 305 m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR); 306 if (m == NULL) 307 goto freeit; 308 #ifdef MAC 309 mac_netinet_icmp_reply(n, m); 310 #endif 311 icmplen = min(icmplen, M_TRAILINGSPACE(m) - 312 sizeof(struct ip) - ICMP_MINLEN); 313 m_align(m, sizeof(struct ip) + ICMP_MINLEN + icmplen); 314 m->m_data += sizeof(struct ip); 315 m->m_len = ICMP_MINLEN + icmplen; 316 317 /* XXX MRT make the outgoing packet use the same FIB 318 * that was associated with the incoming packet 319 */ 320 M_SETFIB(m, M_GETFIB(n)); 321 icp = mtod(m, struct icmp *); 322 ICMPSTAT_INC(icps_outhist[type]); 323 icp->icmp_type = type; 324 if (type == ICMP_REDIRECT) 325 icp->icmp_gwaddr.s_addr = dest; 326 else { 327 icp->icmp_void = 0; 328 /* 329 * The following assignments assume an overlay with the 330 * just zeroed icmp_void field. 331 */ 332 if (type == ICMP_PARAMPROB) { 333 icp->icmp_pptr = code; 334 code = 0; 335 } else if (type == ICMP_UNREACH && 336 code == ICMP_UNREACH_NEEDFRAG && mtu) { 337 icp->icmp_nextmtu = htons(mtu); 338 } 339 } 340 icp->icmp_code = code; 341 342 /* 343 * Copy the quotation into ICMP message and 344 * convert quoted IP header back to network representation. 345 */ 346 m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip); 347 nip = &icp->icmp_ip; 348 349 /* 350 * Set up ICMP message mbuf and copy old IP header (without options 351 * in front of ICMP message. 352 * If the original mbuf was meant to bypass the firewall, the error 353 * reply should bypass as well. 354 */ 355 m->m_flags |= n->m_flags & M_SKIP_FIREWALL; 356 KASSERT(M_LEADINGSPACE(m) >= sizeof(struct ip), 357 ("insufficient space for ip header")); 358 m->m_data -= sizeof(struct ip); 359 m->m_len += sizeof(struct ip); 360 m->m_pkthdr.len = m->m_len; 361 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif; 362 nip = mtod(m, struct ip *); 363 bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip)); 364 nip->ip_len = htons(m->m_len); 365 nip->ip_v = IPVERSION; 366 nip->ip_hl = 5; 367 nip->ip_p = IPPROTO_ICMP; 368 nip->ip_tos = 0; 369 nip->ip_off = 0; 370 icmp_reflect(m); 371 372 freeit: 373 m_freem(n); 374 } 375 376 /* 377 * Process a received ICMP message. 378 */ 379 int 380 icmp_input(struct mbuf **mp, int *offp, int proto) 381 { 382 struct icmp *icp; 383 struct in_ifaddr *ia; 384 struct mbuf *m = *mp; 385 struct ip *ip = mtod(m, struct ip *); 386 struct sockaddr_in icmpsrc, icmpdst, icmpgw; 387 int hlen = *offp; 388 int icmplen = ntohs(ip->ip_len) - *offp; 389 int i, code; 390 void (*ctlfunc)(int, struct sockaddr *, void *); 391 int fibnum; 392 393 *mp = NULL; 394 395 /* 396 * Locate icmp structure in mbuf, and check 397 * that not corrupted and of at least minimum length. 398 */ 399 #ifdef ICMPPRINTFS 400 if (icmpprintfs) { 401 char srcbuf[INET_ADDRSTRLEN]; 402 char dstbuf[INET_ADDRSTRLEN]; 403 404 printf("icmp_input from %s to %s, len %d\n", 405 inet_ntoa_r(ip->ip_src, srcbuf), 406 inet_ntoa_r(ip->ip_dst, dstbuf), icmplen); 407 } 408 #endif 409 if (icmplen < ICMP_MINLEN) { 410 ICMPSTAT_INC(icps_tooshort); 411 goto freeit; 412 } 413 i = hlen + min(icmplen, ICMP_ADVLENMIN); 414 if (m->m_len < i && (m = m_pullup(m, i)) == NULL) { 415 ICMPSTAT_INC(icps_tooshort); 416 return (IPPROTO_DONE); 417 } 418 ip = mtod(m, struct ip *); 419 m->m_len -= hlen; 420 m->m_data += hlen; 421 icp = mtod(m, struct icmp *); 422 if (in_cksum(m, icmplen)) { 423 ICMPSTAT_INC(icps_checksum); 424 goto freeit; 425 } 426 m->m_len += hlen; 427 m->m_data -= hlen; 428 429 #ifdef ICMPPRINTFS 430 if (icmpprintfs) 431 printf("icmp_input, type %d code %d\n", icp->icmp_type, 432 icp->icmp_code); 433 #endif 434 435 /* 436 * Message type specific processing. 437 */ 438 if (icp->icmp_type > ICMP_MAXTYPE) 439 goto raw; 440 441 /* Initialize */ 442 bzero(&icmpsrc, sizeof(icmpsrc)); 443 icmpsrc.sin_len = sizeof(struct sockaddr_in); 444 icmpsrc.sin_family = AF_INET; 445 bzero(&icmpdst, sizeof(icmpdst)); 446 icmpdst.sin_len = sizeof(struct sockaddr_in); 447 icmpdst.sin_family = AF_INET; 448 bzero(&icmpgw, sizeof(icmpgw)); 449 icmpgw.sin_len = sizeof(struct sockaddr_in); 450 icmpgw.sin_family = AF_INET; 451 452 ICMPSTAT_INC(icps_inhist[icp->icmp_type]); 453 code = icp->icmp_code; 454 switch (icp->icmp_type) { 455 456 case ICMP_UNREACH: 457 switch (code) { 458 case ICMP_UNREACH_NET: 459 case ICMP_UNREACH_HOST: 460 case ICMP_UNREACH_SRCFAIL: 461 case ICMP_UNREACH_NET_UNKNOWN: 462 case ICMP_UNREACH_HOST_UNKNOWN: 463 case ICMP_UNREACH_ISOLATED: 464 case ICMP_UNREACH_TOSNET: 465 case ICMP_UNREACH_TOSHOST: 466 case ICMP_UNREACH_HOST_PRECEDENCE: 467 case ICMP_UNREACH_PRECEDENCE_CUTOFF: 468 code = PRC_UNREACH_NET; 469 break; 470 471 case ICMP_UNREACH_NEEDFRAG: 472 code = PRC_MSGSIZE; 473 break; 474 475 /* 476 * RFC 1122, Sections 3.2.2.1 and 4.2.3.9. 477 * Treat subcodes 2,3 as immediate RST 478 */ 479 case ICMP_UNREACH_PROTOCOL: 480 code = PRC_UNREACH_PROTOCOL; 481 break; 482 case ICMP_UNREACH_PORT: 483 code = PRC_UNREACH_PORT; 484 break; 485 486 case ICMP_UNREACH_NET_PROHIB: 487 case ICMP_UNREACH_HOST_PROHIB: 488 case ICMP_UNREACH_FILTER_PROHIB: 489 code = PRC_UNREACH_ADMIN_PROHIB; 490 break; 491 492 default: 493 goto badcode; 494 } 495 goto deliver; 496 497 case ICMP_TIMXCEED: 498 if (code > 1) 499 goto badcode; 500 code += PRC_TIMXCEED_INTRANS; 501 goto deliver; 502 503 case ICMP_PARAMPROB: 504 if (code > 1) 505 goto badcode; 506 code = PRC_PARAMPROB; 507 deliver: 508 /* 509 * Problem with datagram; advise higher level routines. 510 */ 511 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 512 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 513 ICMPSTAT_INC(icps_badlen); 514 goto freeit; 515 } 516 /* Discard ICMP's in response to multicast packets */ 517 if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr))) 518 goto badcode; 519 #ifdef ICMPPRINTFS 520 if (icmpprintfs) 521 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p); 522 #endif 523 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 524 /* 525 * XXX if the packet contains [IPv4 AH TCP], we can't make a 526 * notification to TCP layer. 527 */ 528 i = sizeof(struct ip) + min(icmplen, ICMP_ADVLENPREF(icp)); 529 ip_stripoptions(m); 530 if (m->m_len < i && (m = m_pullup(m, i)) == NULL) { 531 /* This should actually not happen */ 532 ICMPSTAT_INC(icps_tooshort); 533 return (IPPROTO_DONE); 534 } 535 ip = mtod(m, struct ip *); 536 icp = (struct icmp *)(ip + 1); 537 /* 538 * The upper layer handler can rely on: 539 * - The outer IP header has no options. 540 * - The outer IP header, the ICMP header, the inner IP header, 541 * and the first n bytes of the inner payload are contiguous. 542 * n is at least 8, but might be larger based on 543 * ICMP_ADVLENPREF. See its definition in ip_icmp.h. 544 */ 545 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput; 546 if (ctlfunc) 547 (*ctlfunc)(code, (struct sockaddr *)&icmpsrc, 548 (void *)&icp->icmp_ip); 549 break; 550 551 badcode: 552 ICMPSTAT_INC(icps_badcode); 553 break; 554 555 case ICMP_ECHO: 556 if (!V_icmpbmcastecho 557 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) { 558 ICMPSTAT_INC(icps_bmcastecho); 559 break; 560 } 561 if (badport_bandlim(BANDLIM_ICMP_ECHO) < 0) 562 goto freeit; 563 icp->icmp_type = ICMP_ECHOREPLY; 564 goto reflect; 565 566 case ICMP_TSTAMP: 567 if (V_icmptstamprepl == 0) 568 break; 569 if (!V_icmpbmcastecho 570 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) { 571 ICMPSTAT_INC(icps_bmcasttstamp); 572 break; 573 } 574 if (icmplen < ICMP_TSLEN) { 575 ICMPSTAT_INC(icps_badlen); 576 break; 577 } 578 if (badport_bandlim(BANDLIM_ICMP_TSTAMP) < 0) 579 goto freeit; 580 icp->icmp_type = ICMP_TSTAMPREPLY; 581 icp->icmp_rtime = iptime(); 582 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ 583 goto reflect; 584 585 case ICMP_MASKREQ: 586 if (V_icmpmaskrepl == 0) 587 break; 588 /* 589 * We are not able to respond with all ones broadcast 590 * unless we receive it over a point-to-point interface. 591 */ 592 if (icmplen < ICMP_MASKLEN) 593 break; 594 switch (ip->ip_dst.s_addr) { 595 596 case INADDR_BROADCAST: 597 case INADDR_ANY: 598 icmpdst.sin_addr = ip->ip_src; 599 break; 600 601 default: 602 icmpdst.sin_addr = ip->ip_dst; 603 } 604 ia = (struct in_ifaddr *)ifaof_ifpforaddr( 605 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif); 606 if (ia == NULL) 607 break; 608 if (ia->ia_ifp == NULL) { 609 ifa_free(&ia->ia_ifa); 610 break; 611 } 612 icp->icmp_type = ICMP_MASKREPLY; 613 if (V_icmpmaskfake == 0) 614 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; 615 else 616 icp->icmp_mask = V_icmpmaskfake; 617 if (ip->ip_src.s_addr == 0) { 618 if (ia->ia_ifp->if_flags & IFF_BROADCAST) 619 ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr; 620 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) 621 ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr; 622 } 623 ifa_free(&ia->ia_ifa); 624 reflect: 625 ICMPSTAT_INC(icps_reflect); 626 ICMPSTAT_INC(icps_outhist[icp->icmp_type]); 627 icmp_reflect(m); 628 return (IPPROTO_DONE); 629 630 case ICMP_REDIRECT: 631 if (V_log_redirect) { 632 u_long src, dst, gw; 633 634 src = ntohl(ip->ip_src.s_addr); 635 dst = ntohl(icp->icmp_ip.ip_dst.s_addr); 636 gw = ntohl(icp->icmp_gwaddr.s_addr); 637 printf("icmp redirect from %d.%d.%d.%d: " 638 "%d.%d.%d.%d => %d.%d.%d.%d\n", 639 (int)(src >> 24), (int)((src >> 16) & 0xff), 640 (int)((src >> 8) & 0xff), (int)(src & 0xff), 641 (int)(dst >> 24), (int)((dst >> 16) & 0xff), 642 (int)((dst >> 8) & 0xff), (int)(dst & 0xff), 643 (int)(gw >> 24), (int)((gw >> 16) & 0xff), 644 (int)((gw >> 8) & 0xff), (int)(gw & 0xff)); 645 } 646 /* 647 * RFC1812 says we must ignore ICMP redirects if we 648 * are acting as router. 649 */ 650 if (V_drop_redirect || V_ipforwarding) 651 break; 652 if (code > 3) 653 goto badcode; 654 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 655 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 656 ICMPSTAT_INC(icps_badlen); 657 break; 658 } 659 /* 660 * Short circuit routing redirects to force 661 * immediate change in the kernel's routing 662 * tables. The message is also handed to anyone 663 * listening on a raw socket (e.g. the routing 664 * daemon for use in updating its tables). 665 */ 666 icmpgw.sin_addr = ip->ip_src; 667 icmpdst.sin_addr = icp->icmp_gwaddr; 668 #ifdef ICMPPRINTFS 669 if (icmpprintfs) { 670 char dstbuf[INET_ADDRSTRLEN]; 671 char gwbuf[INET_ADDRSTRLEN]; 672 673 printf("redirect dst %s to %s\n", 674 inet_ntoa_r(icp->icmp_ip.ip_dst, dstbuf), 675 inet_ntoa_r(icp->icmp_gwaddr, gwbuf)); 676 } 677 #endif 678 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 679 for ( fibnum = 0; fibnum < rt_numfibs; fibnum++) { 680 in_rtredirect((struct sockaddr *)&icmpsrc, 681 (struct sockaddr *)&icmpdst, 682 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST, 683 (struct sockaddr *)&icmpgw, fibnum); 684 } 685 pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc); 686 break; 687 688 /* 689 * No kernel processing for the following; 690 * just fall through to send to raw listener. 691 */ 692 case ICMP_ECHOREPLY: 693 case ICMP_ROUTERADVERT: 694 case ICMP_ROUTERSOLICIT: 695 case ICMP_TSTAMPREPLY: 696 case ICMP_IREQREPLY: 697 case ICMP_MASKREPLY: 698 case ICMP_SOURCEQUENCH: 699 default: 700 break; 701 } 702 703 raw: 704 *mp = m; 705 rip_input(mp, offp, proto); 706 return (IPPROTO_DONE); 707 708 freeit: 709 m_freem(m); 710 return (IPPROTO_DONE); 711 } 712 713 /* 714 * Reflect the ip packet back to the source 715 */ 716 static void 717 icmp_reflect(struct mbuf *m) 718 { 719 struct rm_priotracker in_ifa_tracker; 720 struct ip *ip = mtod(m, struct ip *); 721 struct ifaddr *ifa; 722 struct ifnet *ifp; 723 struct in_ifaddr *ia; 724 struct in_addr t; 725 struct nhop4_extended nh_ext; 726 struct mbuf *opts = NULL; 727 int optlen = (ip->ip_hl << 2) - sizeof(struct ip); 728 729 if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)) || 730 IN_EXPERIMENTAL(ntohl(ip->ip_src.s_addr)) || 731 IN_ZERONET(ntohl(ip->ip_src.s_addr)) ) { 732 m_freem(m); /* Bad return address */ 733 ICMPSTAT_INC(icps_badaddr); 734 goto done; /* Ip_output() will check for broadcast */ 735 } 736 737 t = ip->ip_dst; 738 ip->ip_dst = ip->ip_src; 739 740 /* 741 * Source selection for ICMP replies: 742 * 743 * If the incoming packet was addressed directly to one of our 744 * own addresses, use dst as the src for the reply. 745 */ 746 IN_IFADDR_RLOCK(&in_ifa_tracker); 747 LIST_FOREACH(ia, INADDR_HASH(t.s_addr), ia_hash) { 748 if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr) { 749 t = IA_SIN(ia)->sin_addr; 750 IN_IFADDR_RUNLOCK(&in_ifa_tracker); 751 goto match; 752 } 753 } 754 IN_IFADDR_RUNLOCK(&in_ifa_tracker); 755 756 /* 757 * If the incoming packet was addressed to one of our broadcast 758 * addresses, use the first non-broadcast address which corresponds 759 * to the incoming interface. 760 */ 761 ifp = m->m_pkthdr.rcvif; 762 if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) { 763 IF_ADDR_RLOCK(ifp); 764 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 765 if (ifa->ifa_addr->sa_family != AF_INET) 766 continue; 767 ia = ifatoia(ifa); 768 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 769 t.s_addr) { 770 t = IA_SIN(ia)->sin_addr; 771 IF_ADDR_RUNLOCK(ifp); 772 goto match; 773 } 774 } 775 IF_ADDR_RUNLOCK(ifp); 776 } 777 /* 778 * If the packet was transiting through us, use the address of 779 * the interface the packet came through in. If that interface 780 * doesn't have a suitable IP address, the normal selection 781 * criteria apply. 782 */ 783 if (V_icmp_rfi && ifp != NULL) { 784 IF_ADDR_RLOCK(ifp); 785 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 786 if (ifa->ifa_addr->sa_family != AF_INET) 787 continue; 788 ia = ifatoia(ifa); 789 t = IA_SIN(ia)->sin_addr; 790 IF_ADDR_RUNLOCK(ifp); 791 goto match; 792 } 793 IF_ADDR_RUNLOCK(ifp); 794 } 795 /* 796 * If the incoming packet was not addressed directly to us, use 797 * designated interface for icmp replies specified by sysctl 798 * net.inet.icmp.reply_src (default not set). Otherwise continue 799 * with normal source selection. 800 */ 801 if (V_reply_src[0] != '\0' && (ifp = ifunit(V_reply_src))) { 802 IF_ADDR_RLOCK(ifp); 803 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 804 if (ifa->ifa_addr->sa_family != AF_INET) 805 continue; 806 ia = ifatoia(ifa); 807 t = IA_SIN(ia)->sin_addr; 808 IF_ADDR_RUNLOCK(ifp); 809 goto match; 810 } 811 IF_ADDR_RUNLOCK(ifp); 812 } 813 /* 814 * If the packet was transiting through us, use the address of 815 * the interface that is the closest to the packet source. 816 * When we don't have a route back to the packet source, stop here 817 * and drop the packet. 818 */ 819 if (fib4_lookup_nh_ext(M_GETFIB(m), ip->ip_dst, 0, 0, &nh_ext) != 0) { 820 m_freem(m); 821 ICMPSTAT_INC(icps_noroute); 822 goto done; 823 } 824 t = nh_ext.nh_src; 825 match: 826 #ifdef MAC 827 mac_netinet_icmp_replyinplace(m); 828 #endif 829 ip->ip_src = t; 830 ip->ip_ttl = V_ip_defttl; 831 832 if (optlen > 0) { 833 u_char *cp; 834 int opt, cnt; 835 u_int len; 836 837 /* 838 * Retrieve any source routing from the incoming packet; 839 * add on any record-route or timestamp options. 840 */ 841 cp = (u_char *) (ip + 1); 842 if ((opts = ip_srcroute(m)) == NULL && 843 (opts = m_gethdr(M_NOWAIT, MT_DATA))) { 844 opts->m_len = sizeof(struct in_addr); 845 mtod(opts, struct in_addr *)->s_addr = 0; 846 } 847 if (opts) { 848 #ifdef ICMPPRINTFS 849 if (icmpprintfs) 850 printf("icmp_reflect optlen %d rt %d => ", 851 optlen, opts->m_len); 852 #endif 853 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { 854 opt = cp[IPOPT_OPTVAL]; 855 if (opt == IPOPT_EOL) 856 break; 857 if (opt == IPOPT_NOP) 858 len = 1; 859 else { 860 if (cnt < IPOPT_OLEN + sizeof(*cp)) 861 break; 862 len = cp[IPOPT_OLEN]; 863 if (len < IPOPT_OLEN + sizeof(*cp) || 864 len > cnt) 865 break; 866 } 867 /* 868 * Should check for overflow, but it "can't happen" 869 */ 870 if (opt == IPOPT_RR || opt == IPOPT_TS || 871 opt == IPOPT_SECURITY) { 872 bcopy((caddr_t)cp, 873 mtod(opts, caddr_t) + opts->m_len, len); 874 opts->m_len += len; 875 } 876 } 877 /* Terminate & pad, if necessary */ 878 cnt = opts->m_len % 4; 879 if (cnt) { 880 for (; cnt < 4; cnt++) { 881 *(mtod(opts, caddr_t) + opts->m_len) = 882 IPOPT_EOL; 883 opts->m_len++; 884 } 885 } 886 #ifdef ICMPPRINTFS 887 if (icmpprintfs) 888 printf("%d\n", opts->m_len); 889 #endif 890 } 891 ip_stripoptions(m); 892 } 893 m_tag_delete_nonpersistent(m); 894 m->m_flags &= ~(M_BCAST|M_MCAST); 895 icmp_send(m, opts); 896 done: 897 if (opts) 898 (void)m_free(opts); 899 } 900 901 /* 902 * Send an icmp packet back to the ip level, 903 * after supplying a checksum. 904 */ 905 static void 906 icmp_send(struct mbuf *m, struct mbuf *opts) 907 { 908 struct ip *ip = mtod(m, struct ip *); 909 int hlen; 910 struct icmp *icp; 911 912 hlen = ip->ip_hl << 2; 913 m->m_data += hlen; 914 m->m_len -= hlen; 915 icp = mtod(m, struct icmp *); 916 icp->icmp_cksum = 0; 917 icp->icmp_cksum = in_cksum(m, ntohs(ip->ip_len) - hlen); 918 m->m_data -= hlen; 919 m->m_len += hlen; 920 m->m_pkthdr.rcvif = (struct ifnet *)0; 921 #ifdef ICMPPRINTFS 922 if (icmpprintfs) { 923 char dstbuf[INET_ADDRSTRLEN]; 924 char srcbuf[INET_ADDRSTRLEN]; 925 926 printf("icmp_send dst %s src %s\n", 927 inet_ntoa_r(ip->ip_dst, dstbuf), 928 inet_ntoa_r(ip->ip_src, srcbuf)); 929 } 930 #endif 931 (void) ip_output(m, opts, NULL, 0, NULL, NULL); 932 } 933 934 /* 935 * Return milliseconds since 00:00 UTC in network format. 936 */ 937 uint32_t 938 iptime(void) 939 { 940 struct timeval atv; 941 u_long t; 942 943 getmicrotime(&atv); 944 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; 945 return (htonl(t)); 946 } 947 948 /* 949 * Return the next larger or smaller MTU plateau (table from RFC 1191) 950 * given current value MTU. If DIR is less than zero, a larger plateau 951 * is returned; otherwise, a smaller value is returned. 952 */ 953 int 954 ip_next_mtu(int mtu, int dir) 955 { 956 static int mtutab[] = { 957 65535, 32000, 17914, 8166, 4352, 2002, 1492, 1280, 1006, 508, 958 296, 68, 0 959 }; 960 int i, size; 961 962 size = (sizeof mtutab) / (sizeof mtutab[0]); 963 if (dir >= 0) { 964 for (i = 0; i < size; i++) 965 if (mtu > mtutab[i]) 966 return mtutab[i]; 967 } else { 968 for (i = size - 1; i >= 0; i--) 969 if (mtu < mtutab[i]) 970 return mtutab[i]; 971 if (mtu == mtutab[0]) 972 return mtutab[0]; 973 } 974 return 0; 975 } 976 #endif /* INET */ 977 978 979 /* 980 * badport_bandlim() - check for ICMP bandwidth limit 981 * 982 * Return 0 if it is ok to send an ICMP error response, -1 if we have 983 * hit our bandwidth limit and it is not ok. 984 * 985 * If icmplim is <= 0, the feature is disabled and 0 is returned. 986 * 987 * For now we separate the TCP and UDP subsystems w/ different 'which' 988 * values. We may eventually remove this separation (and simplify the 989 * code further). 990 * 991 * Note that the printing of the error message is delayed so we can 992 * properly print the icmp error rate that the system was trying to do 993 * (i.e. 22000/100 pps, etc...). This can cause long delays in printing 994 * the 'final' error, but it doesn't make sense to solve the printing 995 * delay with more complex code. 996 */ 997 998 int 999 badport_bandlim(int which) 1000 { 1001 1002 #define N(a) (sizeof (a) / sizeof (a[0])) 1003 static struct rate { 1004 const char *type; 1005 struct timeval lasttime; 1006 int curpps; 1007 } rates[BANDLIM_MAX+1] = { 1008 { "icmp unreach response" }, 1009 { "icmp ping response" }, 1010 { "icmp tstamp response" }, 1011 { "closed port RST response" }, 1012 { "open port RST response" }, 1013 { "icmp6 unreach response" }, 1014 { "sctp ootb response" } 1015 }; 1016 1017 /* 1018 * Return ok status if feature disabled or argument out of range. 1019 */ 1020 if (V_icmplim > 0 && (u_int) which < N(rates)) { 1021 struct rate *r = &rates[which]; 1022 int opps = r->curpps; 1023 1024 if (!ppsratecheck(&r->lasttime, &r->curpps, V_icmplim)) 1025 return -1; /* discard packet */ 1026 /* 1027 * If we've dropped below the threshold after having 1028 * rate-limited traffic print the message. This preserves 1029 * the previous behaviour at the expense of added complexity. 1030 */ 1031 if (V_icmplim_output && opps > V_icmplim) 1032 log(LOG_NOTICE, "Limiting %s from %d to %d packets/sec\n", 1033 r->type, opps, V_icmplim); 1034 } 1035 return 0; /* okay to send packet */ 1036 #undef N 1037 }
Cache object: 37e385caa4961203b7121f0086f8c81e
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]