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 49 #include <net/if.h> 50 #include <net/if_types.h> 51 #include <net/if_var.h> 52 #include <net/if_dl.h> 53 #include <net/route.h> 54 #include <net/netisr.h> 55 56 #include <netinet/in.h> 57 #include <netinet/in_systm.h> 58 #include <netinet/in_var.h> 59 #include <netinet/ip.h> 60 #include <netinet/in_pcb.h> 61 #include <netinet/ip_var.h> 62 #include <netinet/ip_options.h> 63 #include <netinet/ip_icmp.h> 64 #include <machine/in_cksum.h> 65 66 #include <sys/socketvar.h> 67 68 #include <security/mac/mac_framework.h> 69 70 static int ip_dosourceroute = 0; 71 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 72 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 73 74 static int ip_acceptsourceroute = 0; 75 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 76 CTLFLAG_RW, &ip_acceptsourceroute, 0, 77 "Enable accepting source routed IP packets"); 78 79 int ip_doopts = 1; /* 0 = ignore, 1 = process, 2 = reject */ 80 SYSCTL_INT(_net_inet_ip, OID_AUTO, process_options, CTLFLAG_RW, 81 &ip_doopts, 0, "Enable IP options processing ([LS]SRR, RR, TS)"); 82 83 static void save_rte(struct mbuf *m, u_char *, struct in_addr); 84 85 /* 86 * Do option processing on a datagram, possibly discarding it if bad options 87 * are encountered, or forwarding it if source-routed. 88 * 89 * The pass argument is used when operating in the IPSTEALTH mode to tell 90 * what options to process: [LS]SRR (pass 0) or the others (pass 1). The 91 * reason for as many as two passes is that when doing IPSTEALTH, non-routing 92 * options should be processed only if the packet is for us. 93 * 94 * Returns 1 if packet has been forwarded/freed, 0 if the packet should be 95 * processed further. 96 */ 97 int 98 ip_dooptions(struct mbuf *m, int pass) 99 { 100 struct ip *ip = mtod(m, struct ip *); 101 u_char *cp; 102 struct in_ifaddr *ia; 103 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 104 struct in_addr *sin, dst; 105 n_time ntime; 106 struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 107 108 /* Ignore or reject packets with IP options. */ 109 if (ip_doopts == 0) 110 return 0; 111 else if (ip_doopts == 2) { 112 type = ICMP_UNREACH; 113 code = ICMP_UNREACH_FILTER_PROHIB; 114 goto bad; 115 } 116 117 dst = ip->ip_dst; 118 cp = (u_char *)(ip + 1); 119 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 120 for (; cnt > 0; cnt -= optlen, cp += optlen) { 121 opt = cp[IPOPT_OPTVAL]; 122 if (opt == IPOPT_EOL) 123 break; 124 if (opt == IPOPT_NOP) 125 optlen = 1; 126 else { 127 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 128 code = &cp[IPOPT_OLEN] - (u_char *)ip; 129 goto bad; 130 } 131 optlen = cp[IPOPT_OLEN]; 132 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 133 code = &cp[IPOPT_OLEN] - (u_char *)ip; 134 goto bad; 135 } 136 } 137 switch (opt) { 138 139 default: 140 break; 141 142 /* 143 * Source routing with record. Find interface with current 144 * destination address. If none on this machine then drop if 145 * strictly routed, or do nothing if loosely routed. Record 146 * interface address and bring up next address component. If 147 * strictly routed make sure next address is on directly 148 * accessible net. 149 */ 150 case IPOPT_LSRR: 151 case IPOPT_SSRR: 152 #ifdef IPSTEALTH 153 if (ipstealth && pass > 0) 154 break; 155 #endif 156 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 157 code = &cp[IPOPT_OLEN] - (u_char *)ip; 158 goto bad; 159 } 160 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 161 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 162 goto bad; 163 } 164 ipaddr.sin_addr = ip->ip_dst; 165 ia = (struct in_ifaddr *) 166 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 167 if (ia == NULL) { 168 if (opt == IPOPT_SSRR) { 169 type = ICMP_UNREACH; 170 code = ICMP_UNREACH_SRCFAIL; 171 goto bad; 172 } 173 if (!ip_dosourceroute) 174 goto nosourcerouting; 175 /* 176 * Loose routing, and not at next destination 177 * yet; nothing to do except forward. 178 */ 179 break; 180 } 181 off--; /* 0 origin */ 182 if (off > optlen - (int)sizeof(struct in_addr)) { 183 /* 184 * End of source route. Should be for us. 185 */ 186 if (!ip_acceptsourceroute) 187 goto nosourcerouting; 188 save_rte(m, cp, ip->ip_src); 189 break; 190 } 191 #ifdef IPSTEALTH 192 if (ipstealth) 193 goto dropit; 194 #endif 195 if (!ip_dosourceroute) { 196 if (ipforwarding) { 197 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 198 /* 199 * Acting as a router, so generate 200 * ICMP 201 */ 202 nosourcerouting: 203 strcpy(buf, inet_ntoa(ip->ip_dst)); 204 log(LOG_WARNING, 205 "attempted source route from %s to %s\n", 206 inet_ntoa(ip->ip_src), buf); 207 type = ICMP_UNREACH; 208 code = ICMP_UNREACH_SRCFAIL; 209 goto bad; 210 } else { 211 /* 212 * Not acting as a router, so 213 * silently drop. 214 */ 215 #ifdef IPSTEALTH 216 dropit: 217 #endif 218 ipstat.ips_cantforward++; 219 m_freem(m); 220 return (1); 221 } 222 } 223 224 /* 225 * locate outgoing interface 226 */ 227 (void)memcpy(&ipaddr.sin_addr, cp + off, 228 sizeof(ipaddr.sin_addr)); 229 230 if (opt == IPOPT_SSRR) { 231 #define INA struct in_ifaddr * 232 #define SA struct sockaddr * 233 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == NULL) 234 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 235 } else 236 /* XXX MRT 0 for routing */ 237 ia = ip_rtaddr(ipaddr.sin_addr, M_GETFIB(m)); 238 if (ia == NULL) { 239 type = ICMP_UNREACH; 240 code = ICMP_UNREACH_SRCFAIL; 241 goto bad; 242 } 243 ip->ip_dst = ipaddr.sin_addr; 244 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 245 sizeof(struct in_addr)); 246 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 247 /* 248 * Let ip_intr's mcast routing check handle mcast pkts 249 */ 250 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 251 break; 252 253 case IPOPT_RR: 254 #ifdef IPSTEALTH 255 if (ipstealth && pass == 0) 256 break; 257 #endif 258 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 259 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 260 goto bad; 261 } 262 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 263 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 264 goto bad; 265 } 266 /* 267 * If no space remains, ignore. 268 */ 269 off--; /* 0 origin */ 270 if (off > optlen - (int)sizeof(struct in_addr)) 271 break; 272 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 273 sizeof(ipaddr.sin_addr)); 274 /* 275 * Locate outgoing interface; if we're the 276 * destination, use the incoming interface (should be 277 * same). 278 */ 279 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL && 280 (ia = ip_rtaddr(ipaddr.sin_addr, M_GETFIB(m))) == NULL) { 281 type = ICMP_UNREACH; 282 code = ICMP_UNREACH_HOST; 283 goto bad; 284 } 285 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 286 sizeof(struct in_addr)); 287 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 288 break; 289 290 case IPOPT_TS: 291 #ifdef IPSTEALTH 292 if (ipstealth && pass == 0) 293 break; 294 #endif 295 code = cp - (u_char *)ip; 296 if (optlen < 4 || optlen > 40) { 297 code = &cp[IPOPT_OLEN] - (u_char *)ip; 298 goto bad; 299 } 300 if ((off = cp[IPOPT_OFFSET]) < 5) { 301 code = &cp[IPOPT_OLEN] - (u_char *)ip; 302 goto bad; 303 } 304 if (off > optlen - (int)sizeof(int32_t)) { 305 cp[IPOPT_OFFSET + 1] += (1 << 4); 306 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 307 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 308 goto bad; 309 } 310 break; 311 } 312 off--; /* 0 origin */ 313 sin = (struct in_addr *)(cp + off); 314 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 315 316 case IPOPT_TS_TSONLY: 317 break; 318 319 case IPOPT_TS_TSANDADDR: 320 if (off + sizeof(n_time) + 321 sizeof(struct in_addr) > optlen) { 322 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 323 goto bad; 324 } 325 ipaddr.sin_addr = dst; 326 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 327 m->m_pkthdr.rcvif); 328 if (ia == NULL) 329 continue; 330 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 331 sizeof(struct in_addr)); 332 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 333 off += sizeof(struct in_addr); 334 break; 335 336 case IPOPT_TS_PRESPEC: 337 if (off + sizeof(n_time) + 338 sizeof(struct in_addr) > optlen) { 339 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 340 goto bad; 341 } 342 (void)memcpy(&ipaddr.sin_addr, sin, 343 sizeof(struct in_addr)); 344 if (ifa_ifwithaddr((SA)&ipaddr) == NULL) 345 continue; 346 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 347 off += sizeof(struct in_addr); 348 break; 349 350 default: 351 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 352 goto bad; 353 } 354 ntime = iptime(); 355 (void)memcpy(cp + off, &ntime, sizeof(n_time)); 356 cp[IPOPT_OFFSET] += sizeof(n_time); 357 } 358 } 359 if (forward && ipforwarding) { 360 ip_forward(m, 1); 361 return (1); 362 } 363 return (0); 364 bad: 365 icmp_error(m, type, code, 0, 0); 366 ipstat.ips_badoptions++; 367 return (1); 368 } 369 370 /* 371 * Save incoming source route for use in replies, to be picked up later by 372 * ip_srcroute if the receiver is interested. 373 */ 374 static void 375 save_rte(struct mbuf *m, u_char *option, struct in_addr dst) 376 { 377 unsigned olen; 378 struct ipopt_tag *opts; 379 380 opts = (struct ipopt_tag *)m_tag_get(PACKET_TAG_IPOPTIONS, 381 sizeof(struct ipopt_tag), M_NOWAIT); 382 if (opts == NULL) 383 return; 384 385 olen = option[IPOPT_OLEN]; 386 if (olen > sizeof(opts->ip_srcrt) - (1 + sizeof(dst))) { 387 m_tag_free((struct m_tag *)opts); 388 return; 389 } 390 bcopy(option, opts->ip_srcrt.srcopt, olen); 391 opts->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 392 opts->ip_srcrt.dst = dst; 393 m_tag_prepend(m, (struct m_tag *)opts); 394 } 395 396 /* 397 * Retrieve incoming source route for use in replies, in the same form used 398 * by setsockopt. The first hop is placed before the options, will be 399 * removed later. 400 */ 401 struct mbuf * 402 ip_srcroute(struct mbuf *m0) 403 { 404 struct in_addr *p, *q; 405 struct mbuf *m; 406 struct ipopt_tag *opts; 407 408 opts = (struct ipopt_tag *)m_tag_find(m0, PACKET_TAG_IPOPTIONS, NULL); 409 if (opts == NULL) 410 return (NULL); 411 412 if (opts->ip_nhops == 0) 413 return (NULL); 414 m = m_get(M_DONTWAIT, MT_DATA); 415 if (m == NULL) 416 return (NULL); 417 418 #define OPTSIZ (sizeof(opts->ip_srcrt.nop) + sizeof(opts->ip_srcrt.srcopt)) 419 420 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 421 m->m_len = opts->ip_nhops * sizeof(struct in_addr) + 422 sizeof(struct in_addr) + OPTSIZ; 423 424 /* 425 * First, save first hop for return route. 426 */ 427 p = &(opts->ip_srcrt.route[opts->ip_nhops - 1]); 428 *(mtod(m, struct in_addr *)) = *p--; 429 430 /* 431 * Copy option fields and padding (nop) to mbuf. 432 */ 433 opts->ip_srcrt.nop = IPOPT_NOP; 434 opts->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 435 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 436 &(opts->ip_srcrt.nop), OPTSIZ); 437 q = (struct in_addr *)(mtod(m, caddr_t) + 438 sizeof(struct in_addr) + OPTSIZ); 439 #undef OPTSIZ 440 /* 441 * Record return path as an IP source route, reversing the path 442 * (pointers are now aligned). 443 */ 444 while (p >= opts->ip_srcrt.route) { 445 *q++ = *p--; 446 } 447 /* 448 * Last hop goes to final destination. 449 */ 450 *q = opts->ip_srcrt.dst; 451 m_tag_delete(m0, (struct m_tag *)opts); 452 return (m); 453 } 454 455 /* 456 * Strip out IP options, at higher level protocol in the kernel. Second 457 * argument is buffer to which options will be moved, and return value is 458 * their length. 459 * 460 * XXX should be deleted; last arg currently ignored. 461 */ 462 void 463 ip_stripoptions(struct mbuf *m, struct mbuf *mopt) 464 { 465 int i; 466 struct ip *ip = mtod(m, struct ip *); 467 caddr_t opts; 468 int olen; 469 470 olen = (ip->ip_hl << 2) - sizeof (struct ip); 471 opts = (caddr_t)(ip + 1); 472 i = m->m_len - (sizeof (struct ip) + olen); 473 bcopy(opts + olen, opts, (unsigned)i); 474 m->m_len -= olen; 475 if (m->m_flags & M_PKTHDR) 476 m->m_pkthdr.len -= olen; 477 ip->ip_v = IPVERSION; 478 ip->ip_hl = sizeof(struct ip) >> 2; 479 } 480 481 /* 482 * Insert IP options into preformed packet. Adjust IP destination as 483 * required for IP source routing, as indicated by a non-zero in_addr at the 484 * start of the options. 485 * 486 * XXX This routine assumes that the packet has no options in place. 487 */ 488 struct mbuf * 489 ip_insertoptions(struct mbuf *m, struct mbuf *opt, int *phlen) 490 { 491 struct ipoption *p = mtod(opt, struct ipoption *); 492 struct mbuf *n; 493 struct ip *ip = mtod(m, struct ip *); 494 unsigned optlen; 495 496 optlen = opt->m_len - sizeof(p->ipopt_dst); 497 if (optlen + ip->ip_len > IP_MAXPACKET) { 498 *phlen = 0; 499 return (m); /* XXX should fail */ 500 } 501 if (p->ipopt_dst.s_addr) 502 ip->ip_dst = p->ipopt_dst; 503 if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) { 504 MGETHDR(n, M_DONTWAIT, MT_DATA); 505 if (n == NULL) { 506 *phlen = 0; 507 return (m); 508 } 509 M_MOVE_PKTHDR(n, m); 510 n->m_pkthdr.rcvif = NULL; 511 #ifdef MAC 512 mac_mbuf_copy(m, n); 513 #endif 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