ip_output.c revision 1542
1/* 2 * Copyright (c) 1982, 1986, 1988, 1990, 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 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)ip_output.c 8.3 (Berkeley) 1/21/94 34 */ 35 36#include <sys/param.h> 37#include <sys/malloc.h> 38#include <sys/mbuf.h> 39#include <sys/errno.h> 40#include <sys/protosw.h> 41#include <sys/socket.h> 42#include <sys/socketvar.h> 43 44#include <net/if.h> 45#include <net/route.h> 46 47#include <netinet/in.h> 48#include <netinet/in_systm.h> 49#include <netinet/ip.h> 50#include <netinet/in_pcb.h> 51#include <netinet/in_var.h> 52#include <netinet/ip_var.h> 53 54#ifdef vax 55#include <machine/mtpr.h> 56#endif 57 58static struct mbuf *ip_insertoptions __P((struct mbuf *, struct mbuf *, int *)); 59static void ip_mloopback 60 __P((struct ifnet *, struct mbuf *, struct sockaddr_in *)); 61 62/* 63 * IP output. The packet in mbuf chain m contains a skeletal IP 64 * header (with len, off, ttl, proto, tos, src, dst). 65 * The mbuf chain containing the packet will be freed. 66 * The mbuf opt, if present, will not be freed. 67 */ 68int 69ip_output(m0, opt, ro, flags, imo) 70 struct mbuf *m0; 71 struct mbuf *opt; 72 struct route *ro; 73 int flags; 74 struct ip_moptions *imo; 75{ 76 register struct ip *ip, *mhip; 77 register struct ifnet *ifp; 78 register struct mbuf *m = m0; 79 register int hlen = sizeof (struct ip); 80 int len, off, error = 0; 81 struct route iproute; 82 struct sockaddr_in *dst; 83 struct in_ifaddr *ia; 84 85#ifdef DIAGNOSTIC 86 if ((m->m_flags & M_PKTHDR) == 0) 87 panic("ip_output no HDR"); 88#endif 89 if (opt) { 90 m = ip_insertoptions(m, opt, &len); 91 hlen = len; 92 } 93 ip = mtod(m, struct ip *); 94 /* 95 * Fill in IP header. 96 */ 97 if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) { 98 ip->ip_v = IPVERSION; 99 ip->ip_off &= IP_DF; 100 ip->ip_id = htons(ip_id++); 101 ip->ip_hl = hlen >> 2; 102 ipstat.ips_localout++; 103 } else { 104 hlen = ip->ip_hl << 2; 105 } 106 /* 107 * Route packet. 108 */ 109 if (ro == 0) { 110 ro = &iproute; 111 bzero((caddr_t)ro, sizeof (*ro)); 112 } 113 dst = (struct sockaddr_in *)&ro->ro_dst; 114 /* 115 * If there is a cached route, 116 * check that it is to the same destination 117 * and is still up. If not, free it and try again. 118 */ 119 if (ro->ro_rt && ((ro->ro_rt->rt_flags & RTF_UP) == 0 || 120 dst->sin_addr.s_addr != ip->ip_dst.s_addr)) { 121 RTFREE(ro->ro_rt); 122 ro->ro_rt = (struct rtentry *)0; 123 } 124 if (ro->ro_rt == 0) { 125 dst->sin_family = AF_INET; 126 dst->sin_len = sizeof(*dst); 127 dst->sin_addr = ip->ip_dst; 128 } 129 /* 130 * If routing to interface only, 131 * short circuit routing lookup. 132 */ 133#define ifatoia(ifa) ((struct in_ifaddr *)(ifa)) 134#define sintosa(sin) ((struct sockaddr *)(sin)) 135 if (flags & IP_ROUTETOIF) { 136 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == 0 && 137 (ia = ifatoia(ifa_ifwithnet(sintosa(dst)))) == 0) { 138 ipstat.ips_noroute++; 139 error = ENETUNREACH; 140 goto bad; 141 } 142 ifp = ia->ia_ifp; 143 ip->ip_ttl = 1; 144 } else { 145 if (ro->ro_rt == 0) 146 rtalloc(ro); 147 if (ro->ro_rt == 0) { 148 ipstat.ips_noroute++; 149 error = EHOSTUNREACH; 150 goto bad; 151 } 152 ia = ifatoia(ro->ro_rt->rt_ifa); 153 ifp = ro->ro_rt->rt_ifp; 154 ro->ro_rt->rt_use++; 155 if (ro->ro_rt->rt_flags & RTF_GATEWAY) 156 dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway; 157 } 158 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 159 struct in_multi *inm; 160 extern struct ifnet loif; 161 162 m->m_flags |= M_MCAST; 163 /* 164 * IP destination address is multicast. Make sure "dst" 165 * still points to the address in "ro". (It may have been 166 * changed to point to a gateway address, above.) 167 */ 168 dst = (struct sockaddr_in *)&ro->ro_dst; 169 /* 170 * See if the caller provided any multicast options 171 */ 172 if (imo != NULL) { 173 ip->ip_ttl = imo->imo_multicast_ttl; 174 if (imo->imo_multicast_ifp != NULL) 175 ifp = imo->imo_multicast_ifp; 176 } else 177 ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL; 178 /* 179 * Confirm that the outgoing interface supports multicast. 180 */ 181 if ((ifp->if_flags & IFF_MULTICAST) == 0) { 182 ipstat.ips_noroute++; 183 error = ENETUNREACH; 184 goto bad; 185 } 186 /* 187 * If source address not specified yet, use address 188 * of outgoing interface. 189 */ 190 if (ip->ip_src.s_addr == INADDR_ANY) { 191 register struct in_ifaddr *ia; 192 193 for (ia = in_ifaddr; ia; ia = ia->ia_next) 194 if (ia->ia_ifp == ifp) { 195 ip->ip_src = IA_SIN(ia)->sin_addr; 196 break; 197 } 198 } 199 200 IN_LOOKUP_MULTI(ip->ip_dst, ifp, inm); 201 if (inm != NULL && 202 (imo == NULL || imo->imo_multicast_loop)) { 203 /* 204 * If we belong to the destination multicast group 205 * on the outgoing interface, and the caller did not 206 * forbid loopback, loop back a copy. 207 */ 208 ip_mloopback(ifp, m, dst); 209 } 210#ifdef MROUTING 211 else { 212 /* 213 * If we are acting as a multicast router, perform 214 * multicast forwarding as if the packet had just 215 * arrived on the interface to which we are about 216 * to send. The multicast forwarding function 217 * recursively calls this function, using the 218 * IP_FORWARDING flag to prevent infinite recursion. 219 * 220 * Multicasts that are looped back by ip_mloopback(), 221 * above, will be forwarded by the ip_input() routine, 222 * if necessary. 223 */ 224 extern struct socket *ip_mrouter; 225 if (ip_mrouter && (flags & IP_FORWARDING) == 0) { 226 if (ip_mforward(m, ifp) != 0) { 227 m_freem(m); 228 goto done; 229 } 230 } 231 } 232#endif 233 /* 234 * Multicasts with a time-to-live of zero may be looped- 235 * back, above, but must not be transmitted on a network. 236 * Also, multicasts addressed to the loopback interface 237 * are not sent -- the above call to ip_mloopback() will 238 * loop back a copy if this host actually belongs to the 239 * destination group on the loopback interface. 240 */ 241 if (ip->ip_ttl == 0 || ifp == &loif) { 242 m_freem(m); 243 goto done; 244 } 245 246 goto sendit; 247 } 248#ifndef notdef 249 /* 250 * If source address not specified yet, use address 251 * of outgoing interface. 252 */ 253 if (ip->ip_src.s_addr == INADDR_ANY) 254 ip->ip_src = IA_SIN(ia)->sin_addr; 255#endif 256 /* 257 * Look for broadcast address and 258 * and verify user is allowed to send 259 * such a packet. 260 */ 261 if (in_broadcast(dst->sin_addr, ifp)) { 262 if ((ifp->if_flags & IFF_BROADCAST) == 0) { 263 error = EADDRNOTAVAIL; 264 goto bad; 265 } 266 if ((flags & IP_ALLOWBROADCAST) == 0) { 267 error = EACCES; 268 goto bad; 269 } 270 /* don't allow broadcast messages to be fragmented */ 271 if ((u_short)ip->ip_len > ifp->if_mtu) { 272 error = EMSGSIZE; 273 goto bad; 274 } 275 m->m_flags |= M_BCAST; 276 } else 277 m->m_flags &= ~M_BCAST; 278 279sendit: 280 /* 281 * If small enough for interface, can just send directly. 282 */ 283 if ((u_short)ip->ip_len <= ifp->if_mtu) { 284 ip->ip_len = htons((u_short)ip->ip_len); 285 ip->ip_off = htons((u_short)ip->ip_off); 286 ip->ip_sum = 0; 287 ip->ip_sum = in_cksum(m, hlen); 288 error = (*ifp->if_output)(ifp, m, 289 (struct sockaddr *)dst, ro->ro_rt); 290 goto done; 291 } 292 /* 293 * Too large for interface; fragment if possible. 294 * Must be able to put at least 8 bytes per fragment. 295 */ 296 if (ip->ip_off & IP_DF) { 297 error = EMSGSIZE; 298 ipstat.ips_cantfrag++; 299 goto bad; 300 } 301 len = (ifp->if_mtu - hlen) &~ 7; 302 if (len < 8) { 303 error = EMSGSIZE; 304 goto bad; 305 } 306 307 { 308 int mhlen, firstlen = len; 309 struct mbuf **mnext = &m->m_nextpkt; 310 311 /* 312 * Loop through length of segment after first fragment, 313 * make new header and copy data of each part and link onto chain. 314 */ 315 m0 = m; 316 mhlen = sizeof (struct ip); 317 for (off = hlen + len; off < (u_short)ip->ip_len; off += len) { 318 MGETHDR(m, M_DONTWAIT, MT_HEADER); 319 if (m == 0) { 320 error = ENOBUFS; 321 ipstat.ips_odropped++; 322 goto sendorfree; 323 } 324 m->m_data += max_linkhdr; 325 mhip = mtod(m, struct ip *); 326 *mhip = *ip; 327 if (hlen > sizeof (struct ip)) { 328 mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip); 329 mhip->ip_hl = mhlen >> 2; 330 } 331 m->m_len = mhlen; 332 mhip->ip_off = ((off - hlen) >> 3) + (ip->ip_off & ~IP_MF); 333 if (ip->ip_off & IP_MF) 334 mhip->ip_off |= IP_MF; 335 if (off + len >= (u_short)ip->ip_len) 336 len = (u_short)ip->ip_len - off; 337 else 338 mhip->ip_off |= IP_MF; 339 mhip->ip_len = htons((u_short)(len + mhlen)); 340 m->m_next = m_copy(m0, off, len); 341 if (m->m_next == 0) { 342 (void) m_free(m); 343 error = ENOBUFS; /* ??? */ 344 ipstat.ips_odropped++; 345 goto sendorfree; 346 } 347 m->m_pkthdr.len = mhlen + len; 348 m->m_pkthdr.rcvif = (struct ifnet *)0; 349 mhip->ip_off = htons((u_short)mhip->ip_off); 350 mhip->ip_sum = 0; 351 mhip->ip_sum = in_cksum(m, mhlen); 352 *mnext = m; 353 mnext = &m->m_nextpkt; 354 ipstat.ips_ofragments++; 355 } 356 /* 357 * Update first fragment by trimming what's been copied out 358 * and updating header, then send each fragment (in order). 359 */ 360 m = m0; 361 m_adj(m, hlen + firstlen - (u_short)ip->ip_len); 362 m->m_pkthdr.len = hlen + firstlen; 363 ip->ip_len = htons((u_short)m->m_pkthdr.len); 364 ip->ip_off = htons((u_short)(ip->ip_off | IP_MF)); 365 ip->ip_sum = 0; 366 ip->ip_sum = in_cksum(m, hlen); 367sendorfree: 368 for (m = m0; m; m = m0) { 369 m0 = m->m_nextpkt; 370 m->m_nextpkt = 0; 371 if (error == 0) 372 error = (*ifp->if_output)(ifp, m, 373 (struct sockaddr *)dst, ro->ro_rt); 374 else 375 m_freem(m); 376 } 377 378 if (error == 0) 379 ipstat.ips_fragmented++; 380 } 381done: 382 if (ro == &iproute && (flags & IP_ROUTETOIF) == 0 && ro->ro_rt) 383 RTFREE(ro->ro_rt); 384 return (error); 385bad: 386 m_freem(m0); 387 goto done; 388} 389 390/* 391 * Insert IP options into preformed packet. 392 * Adjust IP destination as required for IP source routing, 393 * as indicated by a non-zero in_addr at the start of the options. 394 */ 395static struct mbuf * 396ip_insertoptions(m, opt, phlen) 397 register struct mbuf *m; 398 struct mbuf *opt; 399 int *phlen; 400{ 401 register struct ipoption *p = mtod(opt, struct ipoption *); 402 struct mbuf *n; 403 register struct ip *ip = mtod(m, struct ip *); 404 unsigned optlen; 405 406 optlen = opt->m_len - sizeof(p->ipopt_dst); 407 if (optlen + (u_short)ip->ip_len > IP_MAXPACKET) 408 return (m); /* XXX should fail */ 409 if (p->ipopt_dst.s_addr) 410 ip->ip_dst = p->ipopt_dst; 411 if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) { 412 MGETHDR(n, M_DONTWAIT, MT_HEADER); 413 if (n == 0) 414 return (m); 415 n->m_pkthdr.len = m->m_pkthdr.len + optlen; 416 m->m_len -= sizeof(struct ip); 417 m->m_data += sizeof(struct ip); 418 n->m_next = m; 419 m = n; 420 m->m_len = optlen + sizeof(struct ip); 421 m->m_data += max_linkhdr; 422 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 423 } else { 424 m->m_data -= optlen; 425 m->m_len += optlen; 426 m->m_pkthdr.len += optlen; 427 ovbcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 428 } 429 ip = mtod(m, struct ip *); 430 bcopy((caddr_t)p->ipopt_list, (caddr_t)(ip + 1), (unsigned)optlen); 431 *phlen = sizeof(struct ip) + optlen; 432 ip->ip_len += optlen; 433 return (m); 434} 435 436/* 437 * Copy options from ip to jp, 438 * omitting those not copied during fragmentation. 439 */ 440int 441ip_optcopy(ip, jp) 442 struct ip *ip, *jp; 443{ 444 register u_char *cp, *dp; 445 int opt, optlen, cnt; 446 447 cp = (u_char *)(ip + 1); 448 dp = (u_char *)(jp + 1); 449 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 450 for (; cnt > 0; cnt -= optlen, cp += optlen) { 451 opt = cp[0]; 452 if (opt == IPOPT_EOL) 453 break; 454 if (opt == IPOPT_NOP) { 455 /* Preserve for IP mcast tunnel's LSRR alignment. */ 456 *dp++ = IPOPT_NOP; 457 optlen = 1; 458 continue; 459 } else 460 optlen = cp[IPOPT_OLEN]; 461 /* bogus lengths should have been caught by ip_dooptions */ 462 if (optlen > cnt) 463 optlen = cnt; 464 if (IPOPT_COPIED(opt)) { 465 bcopy((caddr_t)cp, (caddr_t)dp, (unsigned)optlen); 466 dp += optlen; 467 } 468 } 469 for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++) 470 *dp++ = IPOPT_EOL; 471 return (optlen); 472} 473 474/* 475 * IP socket option processing. 476 */ 477int 478ip_ctloutput(op, so, level, optname, mp) 479 int op; 480 struct socket *so; 481 int level, optname; 482 struct mbuf **mp; 483{ 484 register struct inpcb *inp = sotoinpcb(so); 485 register struct mbuf *m = *mp; 486 register int optval; 487 int error = 0; 488 489 if (level != IPPROTO_IP) { 490 error = EINVAL; 491 if (op == PRCO_SETOPT && *mp) 492 (void) m_free(*mp); 493 } else switch (op) { 494 495 case PRCO_SETOPT: 496 switch (optname) { 497 case IP_OPTIONS: 498#ifdef notyet 499 case IP_RETOPTS: 500 return (ip_pcbopts(optname, &inp->inp_options, m)); 501#else 502 return (ip_pcbopts(&inp->inp_options, m)); 503#endif 504 505 case IP_TOS: 506 case IP_TTL: 507 case IP_RECVOPTS: 508 case IP_RECVRETOPTS: 509 case IP_RECVDSTADDR: 510 if (m->m_len != sizeof(int)) 511 error = EINVAL; 512 else { 513 optval = *mtod(m, int *); 514 switch (optname) { 515 516 case IP_TOS: 517 inp->inp_ip.ip_tos = optval; 518 break; 519 520 case IP_TTL: 521 inp->inp_ip.ip_ttl = optval; 522 break; 523#define OPTSET(bit) \ 524 if (optval) \ 525 inp->inp_flags |= bit; \ 526 else \ 527 inp->inp_flags &= ~bit; 528 529 case IP_RECVOPTS: 530 OPTSET(INP_RECVOPTS); 531 break; 532 533 case IP_RECVRETOPTS: 534 OPTSET(INP_RECVRETOPTS); 535 break; 536 537 case IP_RECVDSTADDR: 538 OPTSET(INP_RECVDSTADDR); 539 break; 540 } 541 } 542 break; 543#undef OPTSET 544 545 case IP_MULTICAST_IF: 546 case IP_MULTICAST_TTL: 547 case IP_MULTICAST_LOOP: 548 case IP_ADD_MEMBERSHIP: 549 case IP_DROP_MEMBERSHIP: 550 error = ip_setmoptions(optname, &inp->inp_moptions, m); 551 break; 552 553 default: 554 error = ENOPROTOOPT; 555 break; 556 } 557 if (m) 558 (void)m_free(m); 559 break; 560 561 case PRCO_GETOPT: 562 switch (optname) { 563 case IP_OPTIONS: 564 case IP_RETOPTS: 565 *mp = m = m_get(M_WAIT, MT_SOOPTS); 566 if (inp->inp_options) { 567 m->m_len = inp->inp_options->m_len; 568 bcopy(mtod(inp->inp_options, caddr_t), 569 mtod(m, caddr_t), (unsigned)m->m_len); 570 } else 571 m->m_len = 0; 572 break; 573 574 case IP_TOS: 575 case IP_TTL: 576 case IP_RECVOPTS: 577 case IP_RECVRETOPTS: 578 case IP_RECVDSTADDR: 579 *mp = m = m_get(M_WAIT, MT_SOOPTS); 580 m->m_len = sizeof(int); 581 switch (optname) { 582 583 case IP_TOS: 584 optval = inp->inp_ip.ip_tos; 585 break; 586 587 case IP_TTL: 588 optval = inp->inp_ip.ip_ttl; 589 break; 590 591#define OPTBIT(bit) (inp->inp_flags & bit ? 1 : 0) 592 593 case IP_RECVOPTS: 594 optval = OPTBIT(INP_RECVOPTS); 595 break; 596 597 case IP_RECVRETOPTS: 598 optval = OPTBIT(INP_RECVRETOPTS); 599 break; 600 601 case IP_RECVDSTADDR: 602 optval = OPTBIT(INP_RECVDSTADDR); 603 break; 604 } 605 *mtod(m, int *) = optval; 606 break; 607 608 case IP_MULTICAST_IF: 609 case IP_MULTICAST_TTL: 610 case IP_MULTICAST_LOOP: 611 case IP_ADD_MEMBERSHIP: 612 case IP_DROP_MEMBERSHIP: 613 error = ip_getmoptions(optname, inp->inp_moptions, mp); 614 break; 615 616 default: 617 error = ENOPROTOOPT; 618 break; 619 } 620 break; 621 } 622 return (error); 623} 624 625/* 626 * Set up IP options in pcb for insertion in output packets. 627 * Store in mbuf with pointer in pcbopt, adding pseudo-option 628 * with destination address if source routed. 629 */ 630int 631#ifdef notyet 632ip_pcbopts(optname, pcbopt, m) 633 int optname; 634#else 635ip_pcbopts(pcbopt, m) 636#endif 637 struct mbuf **pcbopt; 638 register struct mbuf *m; 639{ 640 register cnt, optlen; 641 register u_char *cp; 642 u_char opt; 643 644 /* turn off any old options */ 645 if (*pcbopt) 646 (void)m_free(*pcbopt); 647 *pcbopt = 0; 648 if (m == (struct mbuf *)0 || m->m_len == 0) { 649 /* 650 * Only turning off any previous options. 651 */ 652 if (m) 653 (void)m_free(m); 654 return (0); 655 } 656 657#ifndef vax 658 if (m->m_len % sizeof(long)) 659 goto bad; 660#endif 661 /* 662 * IP first-hop destination address will be stored before 663 * actual options; move other options back 664 * and clear it when none present. 665 */ 666 if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN]) 667 goto bad; 668 cnt = m->m_len; 669 m->m_len += sizeof(struct in_addr); 670 cp = mtod(m, u_char *) + sizeof(struct in_addr); 671 ovbcopy(mtod(m, caddr_t), (caddr_t)cp, (unsigned)cnt); 672 bzero(mtod(m, caddr_t), sizeof(struct in_addr)); 673 674 for (; cnt > 0; cnt -= optlen, cp += optlen) { 675 opt = cp[IPOPT_OPTVAL]; 676 if (opt == IPOPT_EOL) 677 break; 678 if (opt == IPOPT_NOP) 679 optlen = 1; 680 else { 681 optlen = cp[IPOPT_OLEN]; 682 if (optlen <= IPOPT_OLEN || optlen > cnt) 683 goto bad; 684 } 685 switch (opt) { 686 687 default: 688 break; 689 690 case IPOPT_LSRR: 691 case IPOPT_SSRR: 692 /* 693 * user process specifies route as: 694 * ->A->B->C->D 695 * D must be our final destination (but we can't 696 * check that since we may not have connected yet). 697 * A is first hop destination, which doesn't appear in 698 * actual IP option, but is stored before the options. 699 */ 700 if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr)) 701 goto bad; 702 m->m_len -= sizeof(struct in_addr); 703 cnt -= sizeof(struct in_addr); 704 optlen -= sizeof(struct in_addr); 705 cp[IPOPT_OLEN] = optlen; 706 /* 707 * Move first hop before start of options. 708 */ 709 bcopy((caddr_t)&cp[IPOPT_OFFSET+1], mtod(m, caddr_t), 710 sizeof(struct in_addr)); 711 /* 712 * Then copy rest of options back 713 * to close up the deleted entry. 714 */ 715 ovbcopy((caddr_t)(&cp[IPOPT_OFFSET+1] + 716 sizeof(struct in_addr)), 717 (caddr_t)&cp[IPOPT_OFFSET+1], 718 (unsigned)cnt + sizeof(struct in_addr)); 719 break; 720 } 721 } 722 if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr)) 723 goto bad; 724 *pcbopt = m; 725 return (0); 726 727bad: 728 (void)m_free(m); 729 return (EINVAL); 730} 731 732/* 733 * Set the IP multicast options in response to user setsockopt(). 734 */ 735int 736ip_setmoptions(optname, imop, m) 737 int optname; 738 struct ip_moptions **imop; 739 struct mbuf *m; 740{ 741 register int error = 0; 742 u_char loop; 743 register int i; 744 struct in_addr addr; 745 register struct ip_mreq *mreq; 746 register struct ifnet *ifp; 747 register struct ip_moptions *imo = *imop; 748 struct route ro; 749 register struct sockaddr_in *dst; 750 751 if (imo == NULL) { 752 /* 753 * No multicast option buffer attached to the pcb; 754 * allocate one and initialize to default values. 755 */ 756 imo = (struct ip_moptions*)malloc(sizeof(*imo), M_IPMOPTS, 757 M_WAITOK); 758 759 if (imo == NULL) 760 return (ENOBUFS); 761 *imop = imo; 762 imo->imo_multicast_ifp = NULL; 763 imo->imo_multicast_ttl = IP_DEFAULT_MULTICAST_TTL; 764 imo->imo_multicast_loop = IP_DEFAULT_MULTICAST_LOOP; 765 imo->imo_num_memberships = 0; 766 } 767 768 switch (optname) { 769 770 case IP_MULTICAST_IF: 771 /* 772 * Select the interface for outgoing multicast packets. 773 */ 774 if (m == NULL || m->m_len != sizeof(struct in_addr)) { 775 error = EINVAL; 776 break; 777 } 778 addr = *(mtod(m, struct in_addr *)); 779 /* 780 * INADDR_ANY is used to remove a previous selection. 781 * When no interface is selected, a default one is 782 * chosen every time a multicast packet is sent. 783 */ 784 if (addr.s_addr == INADDR_ANY) { 785 imo->imo_multicast_ifp = NULL; 786 break; 787 } 788 /* 789 * The selected interface is identified by its local 790 * IP address. Find the interface and confirm that 791 * it supports multicasting. 792 */ 793 INADDR_TO_IFP(addr, ifp); 794 if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) { 795 error = EADDRNOTAVAIL; 796 break; 797 } 798 imo->imo_multicast_ifp = ifp; 799 break; 800 801 case IP_MULTICAST_TTL: 802 /* 803 * Set the IP time-to-live for outgoing multicast packets. 804 */ 805 if (m == NULL || m->m_len != 1) { 806 error = EINVAL; 807 break; 808 } 809 imo->imo_multicast_ttl = *(mtod(m, u_char *)); 810 break; 811 812 case IP_MULTICAST_LOOP: 813 /* 814 * Set the loopback flag for outgoing multicast packets. 815 * Must be zero or one. 816 */ 817 if (m == NULL || m->m_len != 1 || 818 (loop = *(mtod(m, u_char *))) > 1) { 819 error = EINVAL; 820 break; 821 } 822 imo->imo_multicast_loop = loop; 823 break; 824 825 case IP_ADD_MEMBERSHIP: 826 /* 827 * Add a multicast group membership. 828 * Group must be a valid IP multicast address. 829 */ 830 if (m == NULL || m->m_len != sizeof(struct ip_mreq)) { 831 error = EINVAL; 832 break; 833 } 834 mreq = mtod(m, struct ip_mreq *); 835 if (!IN_MULTICAST(ntohl(mreq->imr_multiaddr.s_addr))) { 836 error = EINVAL; 837 break; 838 } 839 /* 840 * If no interface address was provided, use the interface of 841 * the route to the given multicast address. 842 */ 843 if (mreq->imr_interface.s_addr == INADDR_ANY) { 844 ro.ro_rt = NULL; 845 dst = (struct sockaddr_in *)&ro.ro_dst; 846 dst->sin_len = sizeof(*dst); 847 dst->sin_family = AF_INET; 848 dst->sin_addr = mreq->imr_multiaddr; 849 rtalloc(&ro); 850 if (ro.ro_rt == NULL) { 851 error = EADDRNOTAVAIL; 852 break; 853 } 854 ifp = ro.ro_rt->rt_ifp; 855 rtfree(ro.ro_rt); 856 } 857 else { 858 INADDR_TO_IFP(mreq->imr_interface, ifp); 859 } 860 /* 861 * See if we found an interface, and confirm that it 862 * supports multicast. 863 */ 864 if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) { 865 error = EADDRNOTAVAIL; 866 break; 867 } 868 /* 869 * See if the membership already exists or if all the 870 * membership slots are full. 871 */ 872 for (i = 0; i < imo->imo_num_memberships; ++i) { 873 if (imo->imo_membership[i]->inm_ifp == ifp && 874 imo->imo_membership[i]->inm_addr.s_addr 875 == mreq->imr_multiaddr.s_addr) 876 break; 877 } 878 if (i < imo->imo_num_memberships) { 879 error = EADDRINUSE; 880 break; 881 } 882 if (i == IP_MAX_MEMBERSHIPS) { 883 error = ETOOMANYREFS; 884 break; 885 } 886 /* 887 * Everything looks good; add a new record to the multicast 888 * address list for the given interface. 889 */ 890 if ((imo->imo_membership[i] = 891 in_addmulti(&mreq->imr_multiaddr, ifp)) == NULL) { 892 error = ENOBUFS; 893 break; 894 } 895 ++imo->imo_num_memberships; 896 break; 897 898 case IP_DROP_MEMBERSHIP: 899 /* 900 * Drop a multicast group membership. 901 * Group must be a valid IP multicast address. 902 */ 903 if (m == NULL || m->m_len != sizeof(struct ip_mreq)) { 904 error = EINVAL; 905 break; 906 } 907 mreq = mtod(m, struct ip_mreq *); 908 if (!IN_MULTICAST(ntohl(mreq->imr_multiaddr.s_addr))) { 909 error = EINVAL; 910 break; 911 } 912 /* 913 * If an interface address was specified, get a pointer 914 * to its ifnet structure. 915 */ 916 if (mreq->imr_interface.s_addr == INADDR_ANY) 917 ifp = NULL; 918 else { 919 INADDR_TO_IFP(mreq->imr_interface, ifp); 920 if (ifp == NULL) { 921 error = EADDRNOTAVAIL; 922 break; 923 } 924 } 925 /* 926 * Find the membership in the membership array. 927 */ 928 for (i = 0; i < imo->imo_num_memberships; ++i) { 929 if ((ifp == NULL || 930 imo->imo_membership[i]->inm_ifp == ifp) && 931 imo->imo_membership[i]->inm_addr.s_addr == 932 mreq->imr_multiaddr.s_addr) 933 break; 934 } 935 if (i == imo->imo_num_memberships) { 936 error = EADDRNOTAVAIL; 937 break; 938 } 939 /* 940 * Give up the multicast address record to which the 941 * membership points. 942 */ 943 in_delmulti(imo->imo_membership[i]); 944 /* 945 * Remove the gap in the membership array. 946 */ 947 for (++i; i < imo->imo_num_memberships; ++i) 948 imo->imo_membership[i-1] = imo->imo_membership[i]; 949 --imo->imo_num_memberships; 950 break; 951 952 default: 953 error = EOPNOTSUPP; 954 break; 955 } 956 957 /* 958 * If all options have default values, no need to keep the mbuf. 959 */ 960 if (imo->imo_multicast_ifp == NULL && 961 imo->imo_multicast_ttl == IP_DEFAULT_MULTICAST_TTL && 962 imo->imo_multicast_loop == IP_DEFAULT_MULTICAST_LOOP && 963 imo->imo_num_memberships == 0) { 964 free(*imop, M_IPMOPTS); 965 *imop = NULL; 966 } 967 968 return (error); 969} 970 971/* 972 * Return the IP multicast options in response to user getsockopt(). 973 */ 974int 975ip_getmoptions(optname, imo, mp) 976 int optname; 977 register struct ip_moptions *imo; 978 register struct mbuf **mp; 979{ 980 u_char *ttl; 981 u_char *loop; 982 struct in_addr *addr; 983 struct in_ifaddr *ia; 984 985 *mp = m_get(M_WAIT, MT_SOOPTS); 986 987 switch (optname) { 988 989 case IP_MULTICAST_IF: 990 addr = mtod(*mp, struct in_addr *); 991 (*mp)->m_len = sizeof(struct in_addr); 992 if (imo == NULL || imo->imo_multicast_ifp == NULL) 993 addr->s_addr = INADDR_ANY; 994 else { 995 IFP_TO_IA(imo->imo_multicast_ifp, ia); 996 addr->s_addr = (ia == NULL) ? INADDR_ANY 997 : IA_SIN(ia)->sin_addr.s_addr; 998 } 999 return (0); 1000 1001 case IP_MULTICAST_TTL: 1002 ttl = mtod(*mp, u_char *); 1003 (*mp)->m_len = 1; 1004 *ttl = (imo == NULL) ? IP_DEFAULT_MULTICAST_TTL 1005 : imo->imo_multicast_ttl; 1006 return (0); 1007 1008 case IP_MULTICAST_LOOP: 1009 loop = mtod(*mp, u_char *); 1010 (*mp)->m_len = 1; 1011 *loop = (imo == NULL) ? IP_DEFAULT_MULTICAST_LOOP 1012 : imo->imo_multicast_loop; 1013 return (0); 1014 1015 default: 1016 return (EOPNOTSUPP); 1017 } 1018} 1019 1020/* 1021 * Discard the IP multicast options. 1022 */ 1023void 1024ip_freemoptions(imo) 1025 register struct ip_moptions *imo; 1026{ 1027 register int i; 1028 1029 if (imo != NULL) { 1030 for (i = 0; i < imo->imo_num_memberships; ++i) 1031 in_delmulti(imo->imo_membership[i]); 1032 free(imo, M_IPMOPTS); 1033 } 1034} 1035 1036/* 1037 * Routine called from ip_output() to loop back a copy of an IP multicast 1038 * packet to the input queue of a specified interface. Note that this 1039 * calls the output routine of the loopback "driver", but with an interface 1040 * pointer that might NOT be &loif -- easier than replicating that code here. 1041 */ 1042static void 1043ip_mloopback(ifp, m, dst) 1044 struct ifnet *ifp; 1045 register struct mbuf *m; 1046 register struct sockaddr_in *dst; 1047{ 1048 register struct ip *ip; 1049 struct mbuf *copym; 1050 1051 copym = m_copy(m, 0, M_COPYALL); 1052 if (copym != NULL) { 1053 /* 1054 * We don't bother to fragment if the IP length is greater 1055 * than the interface's MTU. Can this possibly matter? 1056 */ 1057 ip = mtod(copym, struct ip *); 1058 ip->ip_len = htons((u_short)ip->ip_len); 1059 ip->ip_off = htons((u_short)ip->ip_off); 1060 ip->ip_sum = 0; 1061 ip->ip_sum = in_cksum(copym, ip->ip_hl << 2); 1062 (void) looutput(ifp, copym, (struct sockaddr *)dst, NULL); 1063 } 1064} 1065