1 /* 2 * Copyright (c) 1982, 1986, 1988, 1990, 1993 Regents of the University 3 * of California. All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 * 7 * @(#)ip_output.c 7.30 (Berkeley) 02/12/93 8 */ 9 10 #include <sys/param.h> 11 #include <sys/malloc.h> 12 #include <sys/mbuf.h> 13 #include <sys/errno.h> 14 #include <sys/protosw.h> 15 #include <sys/socket.h> 16 #include <sys/socketvar.h> 17 18 #include <net/if.h> 19 #include <net/route.h> 20 21 #include <netinet/in.h> 22 #include <netinet/in_systm.h> 23 #include <netinet/ip.h> 24 #include <netinet/in_pcb.h> 25 #include <netinet/in_var.h> 26 #include <netinet/ip_var.h> 27 28 #ifdef vax 29 #include <machine/mtpr.h> 30 #endif 31 32 struct mbuf *ip_insertoptions __P((struct mbuf *, struct mbuf *, int *)); 33 static void ip_mloopback __P((struct ifnet *, struct mbuf *, 34 struct sockaddr_in *)); 35 36 /* 37 * IP output. The packet in mbuf chain m contains a skeletal IP 38 * header (with len, off, ttl, proto, tos, src, dst). 39 * The mbuf chain containing the packet will be freed. 40 * The mbuf opt, if present, will not be freed. 41 */ 42 int 43 ip_output(m0, opt, ro, flags, imo) 44 struct mbuf *m0; 45 struct mbuf *opt; 46 struct route *ro; 47 int flags; 48 struct ip_moptions *imo; 49 { 50 register struct ip *ip, *mhip; 51 register struct ifnet *ifp; 52 register struct mbuf *m = m0; 53 register int hlen = sizeof (struct ip); 54 int len, off, error = 0; 55 struct route iproute; 56 struct sockaddr_in *dst; 57 struct in_ifaddr *ia; 58 59 #ifdef DIAGNOSTIC 60 if ((m->m_flags & M_PKTHDR) == 0) 61 panic("ip_output no HDR"); 62 #endif 63 if (opt) { 64 m = ip_insertoptions(m, opt, &len); 65 hlen = len; 66 } 67 ip = mtod(m, struct ip *); 68 /* 69 * Fill in IP header. 70 */ 71 if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) { 72 ip->ip_v = IPVERSION; 73 ip->ip_off &= IP_DF; 74 ip->ip_id = htons(ip_id++); 75 ip->ip_hl = hlen >> 2; 76 ipstat.ips_localout++; 77 } else { 78 hlen = ip->ip_hl << 2; 79 } 80 /* 81 * Route packet. 82 */ 83 if (ro == 0) { 84 ro = &iproute; 85 bzero((caddr_t)ro, sizeof (*ro)); 86 } 87 dst = (struct sockaddr_in *)&ro->ro_dst; 88 /* 89 * If there is a cached route, 90 * check that it is to the same destination 91 * and is still up. If not, free it and try again. 92 */ 93 if (ro->ro_rt && ((ro->ro_rt->rt_flags & RTF_UP) == 0 || 94 dst->sin_addr.s_addr != ip->ip_dst.s_addr)) { 95 RTFREE(ro->ro_rt); 96 ro->ro_rt = (struct rtentry *)0; 97 } 98 if (ro->ro_rt == 0) { 99 dst->sin_family = AF_INET; 100 dst->sin_len = sizeof(*dst); 101 dst->sin_addr = ip->ip_dst; 102 } 103 /* 104 * If routing to interface only, 105 * short circuit routing lookup. 106 */ 107 if (flags & IP_ROUTETOIF) { 108 109 ia = (struct in_ifaddr *)ifa_ifwithdstaddr((struct sockaddr *)dst); 110 if (ia == 0) 111 ia = in_iaonnetof(in_netof(ip->ip_dst)); 112 if (ia == 0) { 113 ipstat.ips_noroute++; 114 error = ENETUNREACH; 115 goto bad; 116 } 117 ifp = ia->ia_ifp; 118 } else { 119 if (ro->ro_rt == 0) 120 rtalloc(ro); 121 if (ro->ro_rt == 0) { 122 ipstat.ips_noroute++; 123 error = EHOSTUNREACH; 124 goto bad; 125 } 126 ia = (struct in_ifaddr *)ro->ro_rt->rt_ifa; 127 ifp = ro->ro_rt->rt_ifp; 128 ro->ro_rt->rt_use++; 129 if (ro->ro_rt->rt_flags & RTF_GATEWAY) 130 dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway; 131 } 132 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 133 struct in_multi *inm; 134 extern struct ifnet loif; 135 136 m->m_flags |= M_MCAST; 137 /* 138 * IP destination address is multicast. Make sure "dst" 139 * still points to the address in "ro". (It may have been 140 * changed to point to a gateway address, above.) 141 */ 142 dst = (struct sockaddr_in *)&ro->ro_dst; 143 /* 144 * See if the caller provided any multicast options 145 */ 146 if (imo != NULL) { 147 ip->ip_ttl = imo->imo_multicast_ttl; 148 if (imo->imo_multicast_ifp != NULL) 149 ifp = imo->imo_multicast_ifp; 150 } else 151 ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL; 152 /* 153 * Confirm that the outgoing interface supports multicast. 154 */ 155 if ((ifp->if_flags & IFF_MULTICAST) == 0) { 156 ipstat.ips_noroute++; 157 error = ENETUNREACH; 158 goto bad; 159 } 160 /* 161 * If source address not specified yet, use address 162 * of outgoing interface. 163 */ 164 if (ip->ip_src.s_addr == INADDR_ANY) { 165 register struct in_ifaddr *ia; 166 167 for (ia = in_ifaddr; ia; ia = ia->ia_next) 168 if (ia->ia_ifp == ifp) { 169 ip->ip_src = IA_SIN(ia)->sin_addr; 170 break; 171 } 172 } 173 174 IN_LOOKUP_MULTI(ip->ip_dst, ifp, inm); 175 if (inm != NULL && 176 (imo == NULL || imo->imo_multicast_loop)) { 177 /* 178 * If we belong to the destination multicast group 179 * on the outgoing interface, and the caller did not 180 * forbid loopback, loop back a copy. 181 */ 182 ip_mloopback(ifp, m, dst); 183 } 184 #ifdef MROUTING 185 else { 186 /* 187 * If we are acting as a multicast router, perform 188 * multicast forwarding as if the packet had just 189 * arrived on the interface to which we are about 190 * to send. The multicast forwarding function 191 * recursively calls this function, using the 192 * IP_FORWARDING flag to prevent infinite recursion. 193 * 194 * Multicasts that are looped back by ip_mloopback(), 195 * above, will be forwarded by the ip_input() routine, 196 * if necessary. 197 */ 198 extern struct socket *ip_mrouter; 199 if (ip_mrouter && (flags & IP_FORWARDING) == 0) { 200 if (ip_mforward(m, ifp) != 0) { 201 m_freem(m); 202 goto done; 203 } 204 } 205 } 206 #endif 207 /* 208 * Multicasts with a time-to-live of zero may be looped- 209 * back, above, but must not be transmitted on a network. 210 * Also, multicasts addressed to the loopback interface 211 * are not sent -- the above call to ip_mloopback() will 212 * loop back a copy if this host actually belongs to the 213 * destination group on the loopback interface. 214 */ 215 if (ip->ip_ttl == 0 || ifp == &loif) { 216 m_freem(m); 217 goto done; 218 } 219 220 goto sendit; 221 } 222 #ifndef notdef 223 /* 224 * If source address not specified yet, use address 225 * of outgoing interface. 226 */ 227 if (ip->ip_src.s_addr == INADDR_ANY) 228 ip->ip_src = IA_SIN(ia)->sin_addr; 229 #endif 230 /* 231 * Look for broadcast address and 232 * and verify user is allowed to send 233 * such a packet. 234 */ 235 if (in_broadcast(dst->sin_addr)) { 236 if ((ifp->if_flags & IFF_BROADCAST) == 0) { 237 error = EADDRNOTAVAIL; 238 goto bad; 239 } 240 if ((flags & IP_ALLOWBROADCAST) == 0) { 241 error = EACCES; 242 goto bad; 243 } 244 /* don't allow broadcast messages to be fragmented */ 245 if ((u_short)ip->ip_len > ifp->if_mtu) { 246 error = EMSGSIZE; 247 goto bad; 248 } 249 m->m_flags |= M_BCAST; 250 } else 251 m->m_flags &= ~M_BCAST; 252 253 sendit: 254 /* 255 * If small enough for interface, can just send directly. 256 */ 257 if ((u_short)ip->ip_len <= ifp->if_mtu) { 258 ip->ip_len = htons((u_short)ip->ip_len); 259 ip->ip_off = htons((u_short)ip->ip_off); 260 ip->ip_sum = 0; 261 ip->ip_sum = in_cksum(m, hlen); 262 error = (*ifp->if_output)(ifp, m, 263 (struct sockaddr *)dst, ro->ro_rt); 264 goto done; 265 } 266 /* 267 * Too large for interface; fragment if possible. 268 * Must be able to put at least 8 bytes per fragment. 269 */ 270 if (ip->ip_off & IP_DF) { 271 error = EMSGSIZE; 272 ipstat.ips_cantfrag++; 273 goto bad; 274 } 275 len = (ifp->if_mtu - hlen) &~ 7; 276 if (len < 8) { 277 error = EMSGSIZE; 278 goto bad; 279 } 280 281 { 282 int mhlen, firstlen = len; 283 struct mbuf **mnext = &m->m_nextpkt; 284 285 /* 286 * Loop through length of segment after first fragment, 287 * make new header and copy data of each part and link onto chain. 288 */ 289 m0 = m; 290 mhlen = sizeof (struct ip); 291 for (off = hlen + len; off < (u_short)ip->ip_len; off += len) { 292 MGETHDR(m, M_DONTWAIT, MT_HEADER); 293 if (m == 0) { 294 error = ENOBUFS; 295 ipstat.ips_odropped++; 296 goto sendorfree; 297 } 298 m->m_data += max_linkhdr; 299 mhip = mtod(m, struct ip *); 300 *mhip = *ip; 301 if (hlen > sizeof (struct ip)) { 302 mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip); 303 mhip->ip_hl = mhlen >> 2; 304 } 305 m->m_len = mhlen; 306 mhip->ip_off = ((off - hlen) >> 3) + (ip->ip_off & ~IP_MF); 307 if (ip->ip_off & IP_MF) 308 mhip->ip_off |= IP_MF; 309 if (off + len >= (u_short)ip->ip_len) 310 len = (u_short)ip->ip_len - off; 311 else 312 mhip->ip_off |= IP_MF; 313 mhip->ip_len = htons((u_short)(len + mhlen)); 314 m->m_next = m_copy(m0, off, len); 315 if (m->m_next == 0) { 316 error = ENOBUFS; /* ??? */ 317 ipstat.ips_odropped++; 318 goto sendorfree; 319 } 320 m->m_pkthdr.len = mhlen + len; 321 m->m_pkthdr.rcvif = (struct ifnet *)0; 322 mhip->ip_off = htons((u_short)mhip->ip_off); 323 mhip->ip_sum = 0; 324 mhip->ip_sum = in_cksum(m, mhlen); 325 *mnext = m; 326 mnext = &m->m_nextpkt; 327 ipstat.ips_ofragments++; 328 } 329 /* 330 * Update first fragment by trimming what's been copied out 331 * and updating header, then send each fragment (in order). 332 */ 333 m = m0; 334 m_adj(m, hlen + firstlen - (u_short)ip->ip_len); 335 m->m_pkthdr.len = hlen + firstlen; 336 ip->ip_len = htons((u_short)m->m_pkthdr.len); 337 ip->ip_off = htons((u_short)(ip->ip_off | IP_MF)); 338 ip->ip_sum = 0; 339 ip->ip_sum = in_cksum(m, hlen); 340 sendorfree: 341 for (m = m0; m; m = m0) { 342 m0 = m->m_nextpkt; 343 m->m_nextpkt = 0; 344 if (error == 0) 345 error = (*ifp->if_output)(ifp, m, 346 (struct sockaddr *)dst, ro->ro_rt); 347 else 348 m_freem(m); 349 } 350 351 if (error == 0) 352 ipstat.ips_fragmented++; 353 } 354 done: 355 if (ro == &iproute && (flags & IP_ROUTETOIF) == 0 && ro->ro_rt) 356 RTFREE(ro->ro_rt); 357 return (error); 358 bad: 359 m_freem(m0); 360 goto done; 361 } 362 363 /* 364 * Insert IP options into preformed packet. 365 * Adjust IP destination as required for IP source routing, 366 * as indicated by a non-zero in_addr at the start of the options. 367 */ 368 struct mbuf * 369 ip_insertoptions(m, opt, phlen) 370 register struct mbuf *m; 371 struct mbuf *opt; 372 int *phlen; 373 { 374 register struct ipoption *p = mtod(opt, struct ipoption *); 375 struct mbuf *n; 376 register struct ip *ip = mtod(m, struct ip *); 377 unsigned optlen; 378 379 optlen = opt->m_len - sizeof(p->ipopt_dst); 380 if (optlen + (u_short)ip->ip_len > IP_MAXPACKET) 381 return (m); /* XXX should fail */ 382 if (p->ipopt_dst.s_addr) 383 ip->ip_dst = p->ipopt_dst; 384 if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) { 385 MGETHDR(n, M_DONTWAIT, MT_HEADER); 386 if (n == 0) 387 return (m); 388 n->m_pkthdr.len = m->m_pkthdr.len + optlen; 389 m->m_len -= sizeof(struct ip); 390 m->m_data += sizeof(struct ip); 391 n->m_next = m; 392 m = n; 393 m->m_len = optlen + sizeof(struct ip); 394 m->m_data += max_linkhdr; 395 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 396 } else { 397 m->m_data -= optlen; 398 m->m_len += optlen; 399 m->m_pkthdr.len += optlen; 400 ovbcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 401 } 402 ip = mtod(m, struct ip *); 403 bcopy((caddr_t)p->ipopt_list, (caddr_t)(ip + 1), (unsigned)optlen); 404 *phlen = sizeof(struct ip) + optlen; 405 ip->ip_len += optlen; 406 return (m); 407 } 408 409 /* 410 * Copy options from ip to jp, 411 * omitting those not copied during fragmentation. 412 */ 413 int 414 ip_optcopy(ip, jp) 415 struct ip *ip, *jp; 416 { 417 register u_char *cp, *dp; 418 int opt, optlen, cnt; 419 420 cp = (u_char *)(ip + 1); 421 dp = (u_char *)(jp + 1); 422 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 423 for (; cnt > 0; cnt -= optlen, cp += optlen) { 424 opt = cp[0]; 425 if (opt == IPOPT_EOL) 426 break; 427 if (opt == IPOPT_NOP) { 428 /* Preserve for IP mcast tunnel's LSRR alignment. */ 429 *dp++ = IPOPT_NOP; 430 optlen = 1; 431 continue; 432 } else 433 optlen = cp[IPOPT_OLEN]; 434 /* bogus lengths should have been caught by ip_dooptions */ 435 if (optlen > cnt) 436 optlen = cnt; 437 if (IPOPT_COPIED(opt)) { 438 bcopy((caddr_t)cp, (caddr_t)dp, (unsigned)optlen); 439 dp += optlen; 440 } 441 } 442 for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++) 443 *dp++ = IPOPT_EOL; 444 return (optlen); 445 } 446 447 /* 448 * IP socket option processing. 449 */ 450 int 451 ip_ctloutput(op, so, level, optname, mp) 452 int op; 453 struct socket *so; 454 int level, optname; 455 struct mbuf **mp; 456 { 457 register struct inpcb *inp = sotoinpcb(so); 458 register struct mbuf *m = *mp; 459 register int optval; 460 int error = 0; 461 462 if (level != IPPROTO_IP) 463 goto freeit; 464 else switch (op) { 465 466 case PRCO_SETOPT: 467 switch (optname) { 468 case IP_OPTIONS: 469 #ifdef notyet 470 case IP_RETOPTS: 471 return (ip_pcbopts(optname, &inp->inp_options, m)); 472 #else 473 return (ip_pcbopts(&inp->inp_options, m)); 474 #endif 475 476 case IP_TOS: 477 case IP_TTL: 478 case IP_RECVOPTS: 479 case IP_RECVRETOPTS: 480 case IP_RECVDSTADDR: 481 if (m->m_len != sizeof(int)) 482 error = EINVAL; 483 else { 484 optval = *mtod(m, int *); 485 switch (optname) { 486 487 case IP_TOS: 488 inp->inp_ip.ip_tos = optval; 489 break; 490 491 case IP_TTL: 492 inp->inp_ip.ip_ttl = optval; 493 break; 494 #define OPTSET(bit) \ 495 if (optval) \ 496 inp->inp_flags |= bit; \ 497 else \ 498 inp->inp_flags &= ~bit; 499 500 case IP_RECVOPTS: 501 OPTSET(INP_RECVOPTS); 502 break; 503 504 case IP_RECVRETOPTS: 505 OPTSET(INP_RECVRETOPTS); 506 break; 507 508 case IP_RECVDSTADDR: 509 OPTSET(INP_RECVDSTADDR); 510 break; 511 } 512 } 513 break; 514 #undef OPTSET 515 516 case IP_MULTICAST_IF: 517 case IP_MULTICAST_TTL: 518 case IP_MULTICAST_LOOP: 519 case IP_ADD_MEMBERSHIP: 520 case IP_DROP_MEMBERSHIP: 521 error = ip_setmoptions(optname, &inp->inp_moptions, m); 522 break; 523 524 freeit: 525 default: 526 error = EINVAL; 527 break; 528 } 529 if (m) 530 (void)m_free(m); 531 break; 532 533 case PRCO_GETOPT: 534 switch (optname) { 535 case IP_OPTIONS: 536 case IP_RETOPTS: 537 *mp = m = m_get(M_WAIT, MT_SOOPTS); 538 if (inp->inp_options) { 539 m->m_len = inp->inp_options->m_len; 540 bcopy(mtod(inp->inp_options, caddr_t), 541 mtod(m, caddr_t), (unsigned)m->m_len); 542 } else 543 m->m_len = 0; 544 break; 545 546 case IP_TOS: 547 case IP_TTL: 548 case IP_RECVOPTS: 549 case IP_RECVRETOPTS: 550 case IP_RECVDSTADDR: 551 *mp = m = m_get(M_WAIT, MT_SOOPTS); 552 m->m_len = sizeof(int); 553 switch (optname) { 554 555 case IP_TOS: 556 optval = inp->inp_ip.ip_tos; 557 break; 558 559 case IP_TTL: 560 optval = inp->inp_ip.ip_ttl; 561 break; 562 563 #define OPTBIT(bit) (inp->inp_flags & bit ? 1 : 0) 564 565 case IP_RECVOPTS: 566 optval = OPTBIT(INP_RECVOPTS); 567 break; 568 569 case IP_RECVRETOPTS: 570 optval = OPTBIT(INP_RECVRETOPTS); 571 break; 572 573 case IP_RECVDSTADDR: 574 optval = OPTBIT(INP_RECVDSTADDR); 575 break; 576 } 577 *mtod(m, int *) = optval; 578 break; 579 580 case IP_MULTICAST_IF: 581 case IP_MULTICAST_TTL: 582 case IP_MULTICAST_LOOP: 583 case IP_ADD_MEMBERSHIP: 584 case IP_DROP_MEMBERSHIP: 585 error = ip_getmoptions(optname, inp->inp_moptions, mp); 586 break; 587 588 default: 589 error = EINVAL; 590 break; 591 } 592 break; 593 } 594 return (error); 595 } 596 597 /* 598 * Set up IP options in pcb for insertion in output packets. 599 * Store in mbuf with pointer in pcbopt, adding pseudo-option 600 * with destination address if source routed. 601 */ 602 int 603 #ifdef notyet 604 ip_pcbopts(optname, pcbopt, m) 605 int optname; 606 #else 607 ip_pcbopts(pcbopt, m) 608 #endif 609 struct mbuf **pcbopt; 610 register struct mbuf *m; 611 { 612 register cnt, optlen; 613 register u_char *cp; 614 u_char opt; 615 616 /* turn off any old options */ 617 if (*pcbopt) 618 (void)m_free(*pcbopt); 619 *pcbopt = 0; 620 if (m == (struct mbuf *)0 || m->m_len == 0) { 621 /* 622 * Only turning off any previous options. 623 */ 624 if (m) 625 (void)m_free(m); 626 return (0); 627 } 628 629 #ifndef vax 630 if (m->m_len % sizeof(long)) 631 goto bad; 632 #endif 633 /* 634 * IP first-hop destination address will be stored before 635 * actual options; move other options back 636 * and clear it when none present. 637 */ 638 if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN]) 639 goto bad; 640 cnt = m->m_len; 641 m->m_len += sizeof(struct in_addr); 642 cp = mtod(m, u_char *) + sizeof(struct in_addr); 643 ovbcopy(mtod(m, caddr_t), (caddr_t)cp, (unsigned)cnt); 644 bzero(mtod(m, caddr_t), sizeof(struct in_addr)); 645 646 for (; cnt > 0; cnt -= optlen, cp += optlen) { 647 opt = cp[IPOPT_OPTVAL]; 648 if (opt == IPOPT_EOL) 649 break; 650 if (opt == IPOPT_NOP) 651 optlen = 1; 652 else { 653 optlen = cp[IPOPT_OLEN]; 654 if (optlen <= IPOPT_OLEN || optlen > cnt) 655 goto bad; 656 } 657 switch (opt) { 658 659 default: 660 break; 661 662 case IPOPT_LSRR: 663 case IPOPT_SSRR: 664 /* 665 * user process specifies route as: 666 * ->A->B->C->D 667 * D must be our final destination (but we can't 668 * check that since we may not have connected yet). 669 * A is first hop destination, which doesn't appear in 670 * actual IP option, but is stored before the options. 671 */ 672 if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr)) 673 goto bad; 674 m->m_len -= sizeof(struct in_addr); 675 cnt -= sizeof(struct in_addr); 676 optlen -= sizeof(struct in_addr); 677 cp[IPOPT_OLEN] = optlen; 678 /* 679 * Move first hop before start of options. 680 */ 681 bcopy((caddr_t)&cp[IPOPT_OFFSET+1], mtod(m, caddr_t), 682 sizeof(struct in_addr)); 683 /* 684 * Then copy rest of options back 685 * to close up the deleted entry. 686 */ 687 ovbcopy((caddr_t)(&cp[IPOPT_OFFSET+1] + 688 sizeof(struct in_addr)), 689 (caddr_t)&cp[IPOPT_OFFSET+1], 690 (unsigned)cnt + sizeof(struct in_addr)); 691 break; 692 } 693 } 694 if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr)) 695 goto bad; 696 *pcbopt = m; 697 return (0); 698 699 bad: 700 (void)m_free(m); 701 return (EINVAL); 702 } 703 704 /* 705 * Set the IP multicast options in response to user setsockopt(). 706 */ 707 int 708 ip_setmoptions(optname, imop, m) 709 int optname; 710 struct ip_moptions **imop; 711 struct mbuf *m; 712 { 713 register int error = 0; 714 u_char loop; 715 register int i; 716 struct in_addr addr; 717 register struct ip_mreq *mreq; 718 register struct ifnet *ifp; 719 register struct ip_moptions *imo = *imop; 720 struct route ro; 721 register struct sockaddr_in *dst; 722 723 if (imo == NULL) { 724 /* 725 * No multicast option buffer attached to the pcb; 726 * allocate one and initialize to default values. 727 */ 728 imo = (struct ip_moptions*)malloc(sizeof(*imo), M_IPMOPTS, 729 M_WAITOK); 730 731 if (imo == NULL) 732 return (ENOBUFS); 733 *imop = imo; 734 imo->imo_multicast_ifp = NULL; 735 imo->imo_multicast_ttl = IP_DEFAULT_MULTICAST_TTL; 736 imo->imo_multicast_loop = IP_DEFAULT_MULTICAST_LOOP; 737 imo->imo_num_memberships = 0; 738 } 739 740 switch (optname) { 741 742 case IP_MULTICAST_IF: 743 /* 744 * Select the interface for outgoing multicast packets. 745 */ 746 if (m == NULL || m->m_len != sizeof(struct in_addr)) { 747 error = EINVAL; 748 break; 749 } 750 addr = *(mtod(m, struct in_addr *)); 751 /* 752 * INADDR_ANY is used to remove a previous selection. 753 * When no interface is selected, a default one is 754 * chosen every time a multicast packet is sent. 755 */ 756 if (addr.s_addr == INADDR_ANY) { 757 imo->imo_multicast_ifp = NULL; 758 break; 759 } 760 /* 761 * The selected interface is identified by its local 762 * IP address. Find the interface and confirm that 763 * it supports multicasting. 764 */ 765 INADDR_TO_IFP(addr, ifp); 766 if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) { 767 error = EADDRNOTAVAIL; 768 break; 769 } 770 imo->imo_multicast_ifp = ifp; 771 break; 772 773 case IP_MULTICAST_TTL: 774 /* 775 * Set the IP time-to-live for outgoing multicast packets. 776 */ 777 if (m == NULL || m->m_len != 1) { 778 error = EINVAL; 779 break; 780 } 781 imo->imo_multicast_ttl = *(mtod(m, u_char *)); 782 break; 783 784 case IP_MULTICAST_LOOP: 785 /* 786 * Set the loopback flag for outgoing multicast packets. 787 * Must be zero or one. 788 */ 789 if (m == NULL || m->m_len != 1 || 790 (loop = *(mtod(m, u_char *))) > 1) { 791 error = EINVAL; 792 break; 793 } 794 imo->imo_multicast_loop = loop; 795 break; 796 797 case IP_ADD_MEMBERSHIP: 798 /* 799 * Add a multicast group membership. 800 * Group must be a valid IP multicast address. 801 */ 802 if (m == NULL || m->m_len != sizeof(struct ip_mreq)) { 803 error = EINVAL; 804 break; 805 } 806 mreq = mtod(m, struct ip_mreq *); 807 if (!IN_MULTICAST(ntohl(mreq->imr_multiaddr.s_addr))) { 808 error = EINVAL; 809 break; 810 } 811 /* 812 * If no interface address was provided, use the interface of 813 * the route to the given multicast address. 814 */ 815 if (mreq->imr_interface.s_addr == INADDR_ANY) { 816 ro.ro_rt = NULL; 817 dst = (struct sockaddr_in *)&ro.ro_dst; 818 dst->sin_len = sizeof(*dst); 819 dst->sin_family = AF_INET; 820 dst->sin_addr = mreq->imr_multiaddr; 821 rtalloc(&ro); 822 if (ro.ro_rt == NULL) { 823 error = EADDRNOTAVAIL; 824 break; 825 } 826 ifp = ro.ro_rt->rt_ifp; 827 rtfree(ro.ro_rt); 828 } 829 else { 830 INADDR_TO_IFP(mreq->imr_interface, ifp); 831 } 832 /* 833 * See if we found an interface, and confirm that it 834 * supports multicast. 835 */ 836 if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) { 837 error = EADDRNOTAVAIL; 838 break; 839 } 840 /* 841 * See if the membership already exists or if all the 842 * membership slots are full. 843 */ 844 for (i = 0; i < imo->imo_num_memberships; ++i) { 845 if (imo->imo_membership[i]->inm_ifp == ifp && 846 imo->imo_membership[i]->inm_addr.s_addr 847 == mreq->imr_multiaddr.s_addr) 848 break; 849 } 850 if (i < imo->imo_num_memberships) { 851 error = EADDRINUSE; 852 break; 853 } 854 if (i == IP_MAX_MEMBERSHIPS) { 855 error = ETOOMANYREFS; 856 break; 857 } 858 /* 859 * Everything looks good; add a new record to the multicast 860 * address list for the given interface. 861 */ 862 if ((imo->imo_membership[i] = 863 in_addmulti(&mreq->imr_multiaddr, ifp)) == NULL) { 864 error = ENOBUFS; 865 break; 866 } 867 ++imo->imo_num_memberships; 868 break; 869 870 case IP_DROP_MEMBERSHIP: 871 /* 872 * Drop a multicast group membership. 873 * Group must be a valid IP multicast address. 874 */ 875 if (m == NULL || m->m_len != sizeof(struct ip_mreq)) { 876 error = EINVAL; 877 break; 878 } 879 mreq = mtod(m, struct ip_mreq *); 880 if (!IN_MULTICAST(ntohl(mreq->imr_multiaddr.s_addr))) { 881 error = EINVAL; 882 break; 883 } 884 /* 885 * If an interface address was specified, get a pointer 886 * to its ifnet structure. 887 */ 888 if (mreq->imr_interface.s_addr == INADDR_ANY) 889 ifp = NULL; 890 else { 891 INADDR_TO_IFP(mreq->imr_interface, ifp); 892 if (ifp == NULL) { 893 error = EADDRNOTAVAIL; 894 break; 895 } 896 } 897 /* 898 * Find the membership in the membership array. 899 */ 900 for (i = 0; i < imo->imo_num_memberships; ++i) { 901 if ((ifp == NULL || 902 imo->imo_membership[i]->inm_ifp == ifp) && 903 imo->imo_membership[i]->inm_addr.s_addr == 904 mreq->imr_multiaddr.s_addr) 905 break; 906 } 907 if (i == imo->imo_num_memberships) { 908 error = EADDRNOTAVAIL; 909 break; 910 } 911 /* 912 * Give up the multicast address record to which the 913 * membership points. 914 */ 915 in_delmulti(imo->imo_membership[i]); 916 /* 917 * Remove the gap in the membership array. 918 */ 919 for (++i; i < imo->imo_num_memberships; ++i) 920 imo->imo_membership[i-1] = imo->imo_membership[i]; 921 --imo->imo_num_memberships; 922 break; 923 924 default: 925 error = EOPNOTSUPP; 926 break; 927 } 928 929 /* 930 * If all options have default values, no need to keep the mbuf. 931 */ 932 if (imo->imo_multicast_ifp == NULL && 933 imo->imo_multicast_ttl == IP_DEFAULT_MULTICAST_TTL && 934 imo->imo_multicast_loop == IP_DEFAULT_MULTICAST_LOOP && 935 imo->imo_num_memberships == 0) { 936 free(*imop, M_IPMOPTS); 937 *imop = NULL; 938 } 939 940 return (error); 941 } 942 943 /* 944 * Return the IP multicast options in response to user getsockopt(). 945 */ 946 int 947 ip_getmoptions(optname, imo, mp) 948 int optname; 949 register struct ip_moptions *imo; 950 register struct mbuf **mp; 951 { 952 u_char *ttl; 953 u_char *loop; 954 struct in_addr *addr; 955 struct in_ifaddr *ia; 956 957 *mp = m_get(M_WAIT, MT_SOOPTS); 958 959 switch (optname) { 960 961 case IP_MULTICAST_IF: 962 addr = mtod(*mp, struct in_addr *); 963 (*mp)->m_len = sizeof(struct in_addr); 964 if (imo == NULL || imo->imo_multicast_ifp == NULL) 965 addr->s_addr = INADDR_ANY; 966 else { 967 IFP_TO_IA(imo->imo_multicast_ifp, ia); 968 addr->s_addr = (ia == NULL) ? INADDR_ANY 969 : IA_SIN(ia)->sin_addr.s_addr; 970 } 971 return (0); 972 973 case IP_MULTICAST_TTL: 974 ttl = mtod(*mp, u_char *); 975 (*mp)->m_len = 1; 976 *ttl = (imo == NULL) ? IP_DEFAULT_MULTICAST_TTL 977 : imo->imo_multicast_ttl; 978 return (0); 979 980 case IP_MULTICAST_LOOP: 981 loop = mtod(*mp, u_char *); 982 (*mp)->m_len = 1; 983 *loop = (imo == NULL) ? IP_DEFAULT_MULTICAST_LOOP 984 : imo->imo_multicast_loop; 985 return (0); 986 987 default: 988 return (EOPNOTSUPP); 989 } 990 } 991 992 /* 993 * Discard the IP multicast options. 994 */ 995 void 996 ip_freemoptions(imo) 997 register struct ip_moptions *imo; 998 { 999 register int i; 1000 1001 if (imo != NULL) { 1002 for (i = 0; i < imo->imo_num_memberships; ++i) 1003 in_delmulti(imo->imo_membership[i]); 1004 free(imo, M_IPMOPTS); 1005 } 1006 } 1007 1008 /* 1009 * Routine called from ip_output() to loop back a copy of an IP multicast 1010 * packet to the input queue of a specified interface. Note that this 1011 * calls the output routine of the loopback "driver", but with an interface 1012 * pointer that might NOT be &loif -- easier than replicating that code here. 1013 */ 1014 static void 1015 ip_mloopback(ifp, m, dst) 1016 struct ifnet *ifp; 1017 register struct mbuf *m; 1018 register struct sockaddr_in *dst; 1019 { 1020 register struct ip *ip; 1021 struct mbuf *copym; 1022 1023 copym = m_copy(m, 0, M_COPYALL); 1024 if (copym != NULL) { 1025 /* 1026 * We don't bother to fragment if the IP length is greater 1027 * than the interface's MTU. Can this possibly matter? 1028 */ 1029 ip = mtod(copym, struct ip *); 1030 ip->ip_len = htons((u_short)ip->ip_len); 1031 ip->ip_off = htons((u_short)ip->ip_off); 1032 ip->ip_sum = 0; 1033 ip->ip_sum = in_cksum(copym, ip->ip_hl << 2); 1034 (void) looutput(ifp, copym, (struct sockaddr *)dst); 1035 } 1036 } 1037