1 /* 2 * Copyright (c) 1982, 1986, 1988, 1993 3 * The Regents of the University of California. 4 * Copyright (c) 2005 Andre Oppermann, Internet Business Solutions AG. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 4. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 #include "opt_ipstealth.h" 36 #include "opt_mac.h" 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/mbuf.h> 41 #include <sys/domain.h> 42 #include <sys/protosw.h> 43 #include <sys/socket.h> 44 #include <sys/time.h> 45 #include <sys/kernel.h> 46 #include <sys/syslog.h> 47 #include <sys/sysctl.h> 48 #include <sys/vimage.h> 49 50 #include <net/if.h> 51 #include <net/if_types.h> 52 #include <net/if_var.h> 53 #include <net/if_dl.h> 54 #include <net/route.h> 55 #include <net/netisr.h> 56 57 #include <netinet/in.h> 58 #include <netinet/in_systm.h> 59 #include <netinet/in_var.h> 60 #include <netinet/ip.h> 61 #include <netinet/in_pcb.h> 62 #include <netinet/ip_var.h> 63 #include <netinet/ip_options.h> 64 #include <netinet/ip_icmp.h> 65 #include <machine/in_cksum.h> 66 #include <netinet/vinet.h> 67 68 #include <sys/socketvar.h> 69 70 #include <security/mac/mac_framework.h> 71 72 static int ip_dosourceroute = 0; 73 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 74 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 75 76 static int ip_acceptsourceroute = 0; 77 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 78 CTLFLAG_RW, &ip_acceptsourceroute, 0, 79 "Enable accepting source routed IP packets"); 80 81 int ip_doopts = 1; /* 0 = ignore, 1 = process, 2 = reject */ 82 SYSCTL_INT(_net_inet_ip, OID_AUTO, process_options, CTLFLAG_RW, 83 &ip_doopts, 0, "Enable IP options processing ([LS]SRR, RR, TS)"); 84 85 static void save_rte(struct mbuf *m, u_char *, struct in_addr); 86 87 /* 88 * Do option processing on a datagram, possibly discarding it if bad options 89 * are encountered, or forwarding it if source-routed. 90 * 91 * The pass argument is used when operating in the IPSTEALTH mode to tell 92 * what options to process: [LS]SRR (pass 0) or the others (pass 1). The 93 * reason for as many as two passes is that when doing IPSTEALTH, non-routing 94 * options should be processed only if the packet is for us. 95 * 96 * Returns 1 if packet has been forwarded/freed, 0 if the packet should be 97 * processed further. 98 */ 99 int 100 ip_dooptions(struct mbuf *m, int pass) 101 { 102 INIT_VNET_INET(curvnet); 103 struct ip *ip = mtod(m, struct ip *); 104 u_char *cp; 105 struct in_ifaddr *ia; 106 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 107 struct in_addr *sin, dst; 108 uint32_t ntime; 109 struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 110 111 /* Ignore or reject packets with IP options. */ 112 if (ip_doopts == 0) 113 return 0; 114 else if (ip_doopts == 2) { 115 type = ICMP_UNREACH; 116 code = ICMP_UNREACH_FILTER_PROHIB; 117 goto bad; 118 } 119 120 dst = ip->ip_dst; 121 cp = (u_char *)(ip + 1); 122 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 123 for (; cnt > 0; cnt -= optlen, cp += optlen) { 124 opt = cp[IPOPT_OPTVAL]; 125 if (opt == IPOPT_EOL) 126 break; 127 if (opt == IPOPT_NOP) 128 optlen = 1; 129 else { 130 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 131 code = &cp[IPOPT_OLEN] - (u_char *)ip; 132 goto bad; 133 } 134 optlen = cp[IPOPT_OLEN]; 135 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 136 code = &cp[IPOPT_OLEN] - (u_char *)ip; 137 goto bad; 138 } 139 } 140 switch (opt) { 141 142 default: 143 break; 144 145 /* 146 * Source routing with record. Find interface with current 147 * destination address. If none on this machine then drop if 148 * strictly routed, or do nothing if loosely routed. Record 149 * interface address and bring up next address component. If 150 * strictly routed make sure next address is on directly 151 * accessible net. 152 */ 153 case IPOPT_LSRR: 154 case IPOPT_SSRR: 155 #ifdef IPSTEALTH 156 if (V_ipstealth && pass > 0) 157 break; 158 #endif 159 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 160 code = &cp[IPOPT_OLEN] - (u_char *)ip; 161 goto bad; 162 } 163 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 164 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 165 goto bad; 166 } 167 ipaddr.sin_addr = ip->ip_dst; 168 ia = (struct in_ifaddr *) 169 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 170 if (ia == NULL) { 171 if (opt == IPOPT_SSRR) { 172 type = ICMP_UNREACH; 173 code = ICMP_UNREACH_SRCFAIL; 174 goto bad; 175 } 176 if (!ip_dosourceroute) 177 goto nosourcerouting; 178 /* 179 * Loose routing, and not at next destination 180 * yet; nothing to do except forward. 181 */ 182 break; 183 } 184 off--; /* 0 origin */ 185 if (off > optlen - (int)sizeof(struct in_addr)) { 186 /* 187 * End of source route. Should be for us. 188 */ 189 if (!ip_acceptsourceroute) 190 goto nosourcerouting; 191 save_rte(m, cp, ip->ip_src); 192 break; 193 } 194 #ifdef IPSTEALTH 195 if (V_ipstealth) 196 goto dropit; 197 #endif 198 if (!ip_dosourceroute) { 199 if (V_ipforwarding) { 200 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 201 /* 202 * Acting as a router, so generate 203 * ICMP 204 */ 205 nosourcerouting: 206 strcpy(buf, inet_ntoa(ip->ip_dst)); 207 log(LOG_WARNING, 208 "attempted source route from %s to %s\n", 209 inet_ntoa(ip->ip_src), buf); 210 type = ICMP_UNREACH; 211 code = ICMP_UNREACH_SRCFAIL; 212 goto bad; 213 } else { 214 /* 215 * Not acting as a router, so 216 * silently drop. 217 */ 218 #ifdef IPSTEALTH 219 dropit: 220 #endif 221 V_ipstat.ips_cantforward++; 222 m_freem(m); 223 return (1); 224 } 225 } 226 227 /* 228 * locate outgoing interface 229 */ 230 (void)memcpy(&ipaddr.sin_addr, cp + off, 231 sizeof(ipaddr.sin_addr)); 232 233 if (opt == IPOPT_SSRR) { 234 #define INA struct in_ifaddr * 235 #define SA struct sockaddr * 236 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == NULL) 237 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 238 } else 239 /* XXX MRT 0 for routing */ 240 ia = ip_rtaddr(ipaddr.sin_addr, M_GETFIB(m)); 241 if (ia == NULL) { 242 type = ICMP_UNREACH; 243 code = ICMP_UNREACH_SRCFAIL; 244 goto bad; 245 } 246 ip->ip_dst = ipaddr.sin_addr; 247 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 248 sizeof(struct in_addr)); 249 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 250 /* 251 * Let ip_intr's mcast routing check handle mcast pkts 252 */ 253 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 254 break; 255 256 case IPOPT_RR: 257 #ifdef IPSTEALTH 258 if (V_ipstealth && pass == 0) 259 break; 260 #endif 261 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 262 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 263 goto bad; 264 } 265 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 266 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 267 goto bad; 268 } 269 /* 270 * If no space remains, ignore. 271 */ 272 off--; /* 0 origin */ 273 if (off > optlen - (int)sizeof(struct in_addr)) 274 break; 275 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 276 sizeof(ipaddr.sin_addr)); 277 /* 278 * Locate outgoing interface; if we're the 279 * destination, use the incoming interface (should be 280 * same). 281 */ 282 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL && 283 (ia = ip_rtaddr(ipaddr.sin_addr, M_GETFIB(m))) == NULL) { 284 type = ICMP_UNREACH; 285 code = ICMP_UNREACH_HOST; 286 goto bad; 287 } 288 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 289 sizeof(struct in_addr)); 290 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 291 break; 292 293 case IPOPT_TS: 294 #ifdef IPSTEALTH 295 if (V_ipstealth && pass == 0) 296 break; 297 #endif 298 code = cp - (u_char *)ip; 299 if (optlen < 4 || optlen > 40) { 300 code = &cp[IPOPT_OLEN] - (u_char *)ip; 301 goto bad; 302 } 303 if ((off = cp[IPOPT_OFFSET]) < 5) { 304 code = &cp[IPOPT_OLEN] - (u_char *)ip; 305 goto bad; 306 } 307 if (off > optlen - (int)sizeof(int32_t)) { 308 cp[IPOPT_OFFSET + 1] += (1 << 4); 309 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 310 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 311 goto bad; 312 } 313 break; 314 } 315 off--; /* 0 origin */ 316 sin = (struct in_addr *)(cp + off); 317 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 318 319 case IPOPT_TS_TSONLY: 320 break; 321 322 case IPOPT_TS_TSANDADDR: 323 if (off + sizeof(uint32_t) + 324 sizeof(struct in_addr) > optlen) { 325 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 326 goto bad; 327 } 328 ipaddr.sin_addr = dst; 329 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 330 m->m_pkthdr.rcvif); 331 if (ia == NULL) 332 continue; 333 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 334 sizeof(struct in_addr)); 335 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 336 off += sizeof(struct in_addr); 337 break; 338 339 case IPOPT_TS_PRESPEC: 340 if (off + sizeof(uint32_t) + 341 sizeof(struct in_addr) > optlen) { 342 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 343 goto bad; 344 } 345 (void)memcpy(&ipaddr.sin_addr, sin, 346 sizeof(struct in_addr)); 347 if (ifa_ifwithaddr((SA)&ipaddr) == NULL) 348 continue; 349 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 350 off += sizeof(struct in_addr); 351 break; 352 353 default: 354 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 355 goto bad; 356 } 357 ntime = iptime(); 358 (void)memcpy(cp + off, &ntime, sizeof(uint32_t)); 359 cp[IPOPT_OFFSET] += sizeof(uint32_t); 360 } 361 } 362 if (forward && V_ipforwarding) { 363 ip_forward(m, 1); 364 return (1); 365 } 366 return (0); 367 bad: 368 icmp_error(m, type, code, 0, 0); 369 V_ipstat.ips_badoptions++; 370 return (1); 371 } 372 373 /* 374 * Save incoming source route for use in replies, to be picked up later by 375 * ip_srcroute if the receiver is interested. 376 */ 377 static void 378 save_rte(struct mbuf *m, u_char *option, struct in_addr dst) 379 { 380 unsigned olen; 381 struct ipopt_tag *opts; 382 383 opts = (struct ipopt_tag *)m_tag_get(PACKET_TAG_IPOPTIONS, 384 sizeof(struct ipopt_tag), M_NOWAIT); 385 if (opts == NULL) 386 return; 387 388 olen = option[IPOPT_OLEN]; 389 if (olen > sizeof(opts->ip_srcrt) - (1 + sizeof(dst))) { 390 m_tag_free((struct m_tag *)opts); 391 return; 392 } 393 bcopy(option, opts->ip_srcrt.srcopt, olen); 394 opts->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 395 opts->ip_srcrt.dst = dst; 396 m_tag_prepend(m, (struct m_tag *)opts); 397 } 398 399 /* 400 * Retrieve incoming source route for use in replies, in the same form used 401 * by setsockopt. The first hop is placed before the options, will be 402 * removed later. 403 */ 404 struct mbuf * 405 ip_srcroute(struct mbuf *m0) 406 { 407 struct in_addr *p, *q; 408 struct mbuf *m; 409 struct ipopt_tag *opts; 410 411 opts = (struct ipopt_tag *)m_tag_find(m0, PACKET_TAG_IPOPTIONS, NULL); 412 if (opts == NULL) 413 return (NULL); 414 415 if (opts->ip_nhops == 0) 416 return (NULL); 417 m = m_get(M_DONTWAIT, MT_DATA); 418 if (m == NULL) 419 return (NULL); 420 421 #define OPTSIZ (sizeof(opts->ip_srcrt.nop) + sizeof(opts->ip_srcrt.srcopt)) 422 423 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 424 m->m_len = opts->ip_nhops * sizeof(struct in_addr) + 425 sizeof(struct in_addr) + OPTSIZ; 426 427 /* 428 * First, save first hop for return route. 429 */ 430 p = &(opts->ip_srcrt.route[opts->ip_nhops - 1]); 431 *(mtod(m, struct in_addr *)) = *p--; 432 433 /* 434 * Copy option fields and padding (nop) to mbuf. 435 */ 436 opts->ip_srcrt.nop = IPOPT_NOP; 437 opts->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 438 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 439 &(opts->ip_srcrt.nop), OPTSIZ); 440 q = (struct in_addr *)(mtod(m, caddr_t) + 441 sizeof(struct in_addr) + OPTSIZ); 442 #undef OPTSIZ 443 /* 444 * Record return path as an IP source route, reversing the path 445 * (pointers are now aligned). 446 */ 447 while (p >= opts->ip_srcrt.route) { 448 *q++ = *p--; 449 } 450 /* 451 * Last hop goes to final destination. 452 */ 453 *q = opts->ip_srcrt.dst; 454 m_tag_delete(m0, (struct m_tag *)opts); 455 return (m); 456 } 457 458 /* 459 * Strip out IP options, at higher level protocol in the kernel. Second 460 * argument is buffer to which options will be moved, and return value is 461 * their length. 462 * 463 * XXX should be deleted; last arg currently ignored. 464 */ 465 void 466 ip_stripoptions(struct mbuf *m, struct mbuf *mopt) 467 { 468 int i; 469 struct ip *ip = mtod(m, struct ip *); 470 caddr_t opts; 471 int olen; 472 473 olen = (ip->ip_hl << 2) - sizeof (struct ip); 474 opts = (caddr_t)(ip + 1); 475 i = m->m_len - (sizeof (struct ip) + olen); 476 bcopy(opts + olen, opts, (unsigned)i); 477 m->m_len -= olen; 478 if (m->m_flags & M_PKTHDR) 479 m->m_pkthdr.len -= olen; 480 ip->ip_v = IPVERSION; 481 ip->ip_hl = sizeof(struct ip) >> 2; 482 } 483 484 /* 485 * Insert IP options into preformed packet. Adjust IP destination as 486 * required for IP source routing, as indicated by a non-zero in_addr at the 487 * start of the options. 488 * 489 * XXX This routine assumes that the packet has no options in place. 490 */ 491 struct mbuf * 492 ip_insertoptions(struct mbuf *m, struct mbuf *opt, int *phlen) 493 { 494 struct ipoption *p = mtod(opt, struct ipoption *); 495 struct mbuf *n; 496 struct ip *ip = mtod(m, struct ip *); 497 unsigned optlen; 498 499 optlen = opt->m_len - sizeof(p->ipopt_dst); 500 if (optlen + ip->ip_len > IP_MAXPACKET) { 501 *phlen = 0; 502 return (m); /* XXX should fail */ 503 } 504 if (p->ipopt_dst.s_addr) 505 ip->ip_dst = p->ipopt_dst; 506 if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) { 507 MGETHDR(n, M_DONTWAIT, MT_DATA); 508 if (n == NULL) { 509 *phlen = 0; 510 return (m); 511 } 512 M_MOVE_PKTHDR(n, m); 513 n->m_pkthdr.rcvif = NULL; 514 n->m_pkthdr.len += optlen; 515 m->m_len -= sizeof(struct ip); 516 m->m_data += sizeof(struct ip); 517 n->m_next = m; 518 m = n; 519 m->m_len = optlen + sizeof(struct ip); 520 m->m_data += max_linkhdr; 521 bcopy(ip, mtod(m, void *), sizeof(struct ip)); 522 } else { 523 m->m_data -= optlen; 524 m->m_len += optlen; 525 m->m_pkthdr.len += optlen; 526 bcopy(ip, mtod(m, void *), sizeof(struct ip)); 527 } 528 ip = mtod(m, struct ip *); 529 bcopy(p->ipopt_list, ip + 1, optlen); 530 *phlen = sizeof(struct ip) + optlen; 531 ip->ip_v = IPVERSION; 532 ip->ip_hl = *phlen >> 2; 533 ip->ip_len += optlen; 534 return (m); 535 } 536 537 /* 538 * Copy options from ip to jp, omitting those not copied during 539 * fragmentation. 540 */ 541 int 542 ip_optcopy(struct ip *ip, struct ip *jp) 543 { 544 u_char *cp, *dp; 545 int opt, optlen, cnt; 546 547 cp = (u_char *)(ip + 1); 548 dp = (u_char *)(jp + 1); 549 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 550 for (; cnt > 0; cnt -= optlen, cp += optlen) { 551 opt = cp[0]; 552 if (opt == IPOPT_EOL) 553 break; 554 if (opt == IPOPT_NOP) { 555 /* Preserve for IP mcast tunnel's LSRR alignment. */ 556 *dp++ = IPOPT_NOP; 557 optlen = 1; 558 continue; 559 } 560 561 KASSERT(cnt >= IPOPT_OLEN + sizeof(*cp), 562 ("ip_optcopy: malformed ipv4 option")); 563 optlen = cp[IPOPT_OLEN]; 564 KASSERT(optlen >= IPOPT_OLEN + sizeof(*cp) && optlen <= cnt, 565 ("ip_optcopy: malformed ipv4 option")); 566 567 /* Bogus lengths should have been caught by ip_dooptions. */ 568 if (optlen > cnt) 569 optlen = cnt; 570 if (IPOPT_COPIED(opt)) { 571 bcopy(cp, dp, optlen); 572 dp += optlen; 573 } 574 } 575 for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++) 576 *dp++ = IPOPT_EOL; 577 return (optlen); 578 } 579 580 /* 581 * Set up IP options in pcb for insertion in output packets. Store in mbuf 582 * with pointer in pcbopt, adding pseudo-option with destination address if 583 * source routed. 584 */ 585 int 586 ip_pcbopts(struct inpcb *inp, int optname, struct mbuf *m) 587 { 588 int cnt, optlen; 589 u_char *cp; 590 struct mbuf **pcbopt; 591 u_char opt; 592 593 INP_WLOCK_ASSERT(inp); 594 595 pcbopt = &inp->inp_options; 596 597 /* turn off any old options */ 598 if (*pcbopt) 599 (void)m_free(*pcbopt); 600 *pcbopt = 0; 601 if (m == NULL || m->m_len == 0) { 602 /* 603 * Only turning off any previous options. 604 */ 605 if (m != NULL) 606 (void)m_free(m); 607 return (0); 608 } 609 610 if (m->m_len % sizeof(int32_t)) 611 goto bad; 612 /* 613 * IP first-hop destination address will be stored before actual 614 * options; move other options back and clear it when none present. 615 */ 616 if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN]) 617 goto bad; 618 cnt = m->m_len; 619 m->m_len += sizeof(struct in_addr); 620 cp = mtod(m, u_char *) + sizeof(struct in_addr); 621 bcopy(mtod(m, void *), cp, (unsigned)cnt); 622 bzero(mtod(m, void *), sizeof(struct in_addr)); 623 624 for (; cnt > 0; cnt -= optlen, cp += optlen) { 625 opt = cp[IPOPT_OPTVAL]; 626 if (opt == IPOPT_EOL) 627 break; 628 if (opt == IPOPT_NOP) 629 optlen = 1; 630 else { 631 if (cnt < IPOPT_OLEN + sizeof(*cp)) 632 goto bad; 633 optlen = cp[IPOPT_OLEN]; 634 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) 635 goto bad; 636 } 637 switch (opt) { 638 639 default: 640 break; 641 642 case IPOPT_LSRR: 643 case IPOPT_SSRR: 644 /* 645 * User process specifies route as: 646 * 647 * ->A->B->C->D 648 * 649 * D must be our final destination (but we can't 650 * check that since we may not have connected yet). 651 * A is first hop destination, which doesn't appear 652 * in actual IP option, but is stored before the 653 * options. 654 */ 655 /* XXX-BZ PRIV_NETINET_SETHDROPTS? */ 656 if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr)) 657 goto bad; 658 m->m_len -= sizeof(struct in_addr); 659 cnt -= sizeof(struct in_addr); 660 optlen -= sizeof(struct in_addr); 661 cp[IPOPT_OLEN] = optlen; 662 /* 663 * Move first hop before start of options. 664 */ 665 bcopy((caddr_t)&cp[IPOPT_OFFSET+1], mtod(m, caddr_t), 666 sizeof(struct in_addr)); 667 /* 668 * Then copy rest of options back 669 * to close up the deleted entry. 670 */ 671 bcopy((&cp[IPOPT_OFFSET+1] + sizeof(struct in_addr)), 672 &cp[IPOPT_OFFSET+1], 673 (unsigned)cnt - (IPOPT_MINOFF - 1)); 674 break; 675 } 676 } 677 if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr)) 678 goto bad; 679 *pcbopt = m; 680 return (0); 681 682 bad: 683 (void)m_free(m); 684 return (EINVAL); 685 } 686