1 /* 2 * Copyright (c) 1982, 1986, 1988, 1990 Regents of the University of California. 3 * All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 * 7 * @(#)ip_output.c 7.25 (Berkeley) 07/06/92 8 */ 9 10 #include "param.h" 11 #include "malloc.h" 12 #include "mbuf.h" 13 #include "errno.h" 14 #include "protosw.h" 15 #include "socket.h" 16 #include "socketvar.h" 17 18 #include "../net/if.h" 19 #include "../net/route.h" 20 21 #include "in.h" 22 #include "in_systm.h" 23 #include "ip.h" 24 #include "in_pcb.h" 25 #include "in_var.h" 26 #include "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 44 #ifdef MULTICAST 45 , imo 46 #endif 47 ) 48 struct mbuf *m0; 49 struct mbuf *opt; 50 struct route *ro; 51 int flags; 52 #ifdef MULTICAST 53 struct ip_moptions *imo; 54 #endif 55 { 56 register struct ip *ip, *mhip; 57 register struct ifnet *ifp; 58 register struct mbuf *m = m0; 59 register int hlen = sizeof (struct ip); 60 int len, off, error = 0; 61 struct route iproute; 62 struct sockaddr_in *dst; 63 struct in_ifaddr *ia; 64 65 #ifdef DIAGNOSTIC 66 if ((m->m_flags & M_PKTHDR) == 0) 67 panic("ip_output no HDR"); 68 #endif 69 if (opt) { 70 m = ip_insertoptions(m, opt, &len); 71 hlen = len; 72 } 73 ip = mtod(m, struct ip *); 74 /* 75 * Fill in IP header. 76 */ 77 if ((flags & IP_FORWARDING) == 0) { 78 ip->ip_v = IPVERSION; 79 ip->ip_off &= IP_DF; 80 ip->ip_id = htons(ip_id++); 81 ip->ip_hl = hlen >> 2; 82 } else { 83 hlen = ip->ip_hl << 2; 84 ipstat.ips_localout++; 85 } 86 /* 87 * Route packet. 88 */ 89 if (ro == 0) { 90 ro = &iproute; 91 bzero((caddr_t)ro, sizeof (*ro)); 92 } 93 dst = (struct sockaddr_in *)&ro->ro_dst; 94 /* 95 * If there is a cached route, 96 * check that it is to the same destination 97 * and is still up. If not, free it and try again. 98 */ 99 if (ro->ro_rt && ((ro->ro_rt->rt_flags & RTF_UP) == 0 || 100 dst->sin_addr.s_addr != ip->ip_dst.s_addr)) { 101 RTFREE(ro->ro_rt); 102 ro->ro_rt = (struct rtentry *)0; 103 } 104 if (ro->ro_rt == 0) { 105 dst->sin_family = AF_INET; 106 dst->sin_len = sizeof(*dst); 107 dst->sin_addr = ip->ip_dst; 108 } 109 /* 110 * If routing to interface only, 111 * short circuit routing lookup. 112 */ 113 if (flags & IP_ROUTETOIF) { 114 115 ia = (struct in_ifaddr *)ifa_ifwithdstaddr((struct sockaddr *)dst); 116 if (ia == 0) 117 ia = in_iaonnetof(in_netof(ip->ip_dst)); 118 if (ia == 0) { 119 error = ENETUNREACH; 120 goto bad; 121 } 122 ifp = ia->ia_ifp; 123 } else { 124 if (ro->ro_rt == 0) 125 rtalloc(ro); 126 if (ro->ro_rt == 0) { 127 error = EHOSTUNREACH; 128 goto bad; 129 } 130 ia = (struct in_ifaddr *)ro->ro_rt->rt_ifa; 131 ifp = ro->ro_rt->rt_ifp; 132 ro->ro_rt->rt_use++; 133 if (ro->ro_rt->rt_flags & RTF_GATEWAY) 134 dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway; 135 } 136 #ifdef MULTICAST 137 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 138 struct in_multi *inm; 139 extern struct ifnet loif; 140 extern struct socket *ip_mrouter; 141 142 m->m_flags |= M_MCAST; 143 /* 144 * IP destination address is multicast. Make sure "dst" 145 * still points to the address in "ro". (It may have been 146 * changed to point to a gateway address, above.) 147 */ 148 dst = (struct sockaddr_in *)&ro->ro_dst; 149 /* 150 * See if the caller provided any multicast options 151 */ 152 if (imo != NULL) { 153 ip->ip_ttl = imo->imo_multicast_ttl; 154 if (imo->imo_multicast_ifp != NULL) 155 ifp = imo->imo_multicast_ifp; 156 } else 157 ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL; 158 /* 159 * Confirm that the outgoing interface supports multicast. 160 */ 161 if ((ifp->if_flags & IFF_MULTICAST) == 0) { 162 error = ENETUNREACH; 163 goto bad; 164 } 165 /* 166 * If source address not specified yet, use address 167 * of outgoing interface. 168 */ 169 if (ip->ip_src.s_addr == INADDR_ANY) { 170 register struct in_ifaddr *ia; 171 172 for (ia = in_ifaddr; ia; ia = ia->ia_next) 173 if (ia->ia_ifp == ifp) { 174 ip->ip_src = IA_SIN(ia)->sin_addr; 175 break; 176 } 177 } 178 179 IN_LOOKUP_MULTI(ip->ip_dst, ifp, inm); 180 if (inm != NULL && 181 (imo == NULL || imo->imo_multicast_loop)) { 182 /* 183 * If we belong to the destination multicast group 184 * on the outgoing interface, and the caller did not 185 * forbid loopback, loop back a copy. 186 */ 187 ip_mloopback(ifp, m, dst); 188 } 189 #ifdef MROUTING 190 else if (ip_mrouter && (flags & IP_FORWARDING) == 0) { 191 /* 192 * If we are acting as a multicast router, perform 193 * multicast forwarding as if the packet had just 194 * arrived on the interface to which we are about 195 * to send. The multicast forwarding function 196 * recursively calls this function, using the 197 * IP_FORWARDING flag to prevent infinite recursion. 198 * 199 * Multicasts that are looped back by ip_mloopback(), 200 * above, will be forwarded by the ip_input() routine, 201 * if necessary. 202 */ 203 if (ip_mforward(m, ifp) != 0) { 204 m_freem(m); 205 goto done; 206 } 207 } 208 #endif 209 /* 210 * Multicasts with a time-to-live of zero may be looped- 211 * back, above, but must not be transmitted on a network. 212 * Also, multicasts addressed to the loopback interface 213 * are not sent -- the above call to ip_mloopback() will 214 * loop back a copy if this host actually belongs to the 215 * destination group on the loopback interface. 216 */ 217 if (ip->ip_ttl == 0 || ifp == &loif) { 218 m_freem(m); 219 goto done; 220 } 221 222 goto sendit; 223 } 224 #endif 225 #ifndef notdef 226 /* 227 * If source address not specified yet, use address 228 * of outgoing interface. 229 */ 230 if (ip->ip_src.s_addr == INADDR_ANY) 231 ip->ip_src = IA_SIN(ia)->sin_addr; 232 #endif 233 /* 234 * Look for broadcast address and 235 * and verify user is allowed to send 236 * such a packet. 237 */ 238 if (in_broadcast(dst->sin_addr)) { 239 if ((ifp->if_flags & IFF_BROADCAST) == 0) { 240 error = EADDRNOTAVAIL; 241 goto bad; 242 } 243 if ((flags & IP_ALLOWBROADCAST) == 0) { 244 error = EACCES; 245 goto bad; 246 } 247 /* don't allow broadcast messages to be fragmented */ 248 if ((u_short)ip->ip_len > ifp->if_mtu) { 249 error = EMSGSIZE; 250 goto bad; 251 } 252 m->m_flags |= M_BCAST; 253 } 254 255 #ifdef MULTICAST 256 sendit: 257 #endif 258 /* 259 * If small enough for interface, can just send directly. 260 */ 261 if ((u_short)ip->ip_len <= ifp->if_mtu) { 262 ip->ip_len = htons((u_short)ip->ip_len); 263 ip->ip_off = htons((u_short)ip->ip_off); 264 ip->ip_sum = 0; 265 ip->ip_sum = in_cksum(m, hlen); 266 error = (*ifp->if_output)(ifp, m, 267 (struct sockaddr *)dst, ro->ro_rt); 268 goto done; 269 } 270 ipstat.ips_fragmented++; 271 /* 272 * Too large for interface; fragment if possible. 273 * Must be able to put at least 8 bytes per fragment. 274 */ 275 if (ip->ip_off & IP_DF) { 276 error = EMSGSIZE; 277 goto bad; 278 } 279 len = (ifp->if_mtu - hlen) &~ 7; 280 if (len < 8) { 281 error = EMSGSIZE; 282 goto bad; 283 } 284 285 { 286 int mhlen, firstlen = len; 287 struct mbuf **mnext = &m->m_nextpkt; 288 289 /* 290 * Loop through length of segment after first fragment, 291 * make new header and copy data of each part and link onto chain. 292 */ 293 m0 = m; 294 mhlen = sizeof (struct ip); 295 for (off = hlen + len; off < (u_short)ip->ip_len; off += len) { 296 MGETHDR(m, M_DONTWAIT, MT_HEADER); 297 if (m == 0) { 298 error = ENOBUFS; 299 goto sendorfree; 300 } 301 m->m_data += max_linkhdr; 302 mhip = mtod(m, struct ip *); 303 *mhip = *ip; 304 if (hlen > sizeof (struct ip)) { 305 mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip); 306 mhip->ip_hl = mhlen >> 2; 307 } 308 m->m_len = mhlen; 309 mhip->ip_off = ((off - hlen) >> 3) + (ip->ip_off & ~IP_MF); 310 if (ip->ip_off & IP_MF) 311 mhip->ip_off |= IP_MF; 312 if (off + len >= (u_short)ip->ip_len) 313 len = (u_short)ip->ip_len - off; 314 else 315 mhip->ip_off |= IP_MF; 316 mhip->ip_len = htons((u_short)(len + mhlen)); 317 m->m_next = m_copy(m0, off, len); 318 if (m->m_next == 0) { 319 error = ENOBUFS; /* ??? */ 320 goto sendorfree; 321 } 322 m->m_pkthdr.len = mhlen + len; 323 m->m_pkthdr.rcvif = (struct ifnet *)0; 324 mhip->ip_off = htons((u_short)mhip->ip_off); 325 mhip->ip_sum = 0; 326 mhip->ip_sum = in_cksum(m, mhlen); 327 *mnext = m; 328 mnext = &m->m_nextpkt; 329 ipstat.ips_ofragments++; 330 } 331 /* 332 * Update first fragment by trimming what's been copied out 333 * and updating header, then send each fragment (in order). 334 */ 335 m = m0; 336 m_adj(m, hlen + firstlen - (u_short)ip->ip_len); 337 m->m_pkthdr.len = hlen + firstlen; 338 ip->ip_len = htons((u_short)m->m_pkthdr.len); 339 ip->ip_off = htons((u_short)(ip->ip_off | IP_MF)); 340 ip->ip_sum = 0; 341 ip->ip_sum = in_cksum(m, hlen); 342 sendorfree: 343 for (m = m0; m; m = m0) { 344 m0 = m->m_nextpkt; 345 m->m_nextpkt = 0; 346 if (error == 0) 347 error = (*ifp->if_output)(ifp, m, 348 (struct sockaddr *)dst, ro->ro_rt); 349 else 350 m_freem(m); 351 } 352 } 353 done: 354 if (ro == &iproute && (flags & IP_ROUTETOIF) == 0 && ro->ro_rt) 355 RTFREE(ro->ro_rt); 356 return (error); 357 bad: 358 m_freem(m0); 359 goto done; 360 } 361 362 /* 363 * Insert IP options into preformed packet. 364 * Adjust IP destination as required for IP source routing, 365 * as indicated by a non-zero in_addr at the start of the options. 366 */ 367 struct mbuf * 368 ip_insertoptions(m, opt, phlen) 369 register struct mbuf *m; 370 struct mbuf *opt; 371 int *phlen; 372 { 373 register struct ipoption *p = mtod(opt, struct ipoption *); 374 struct mbuf *n; 375 register struct ip *ip = mtod(m, struct ip *); 376 unsigned optlen; 377 378 optlen = opt->m_len - sizeof(p->ipopt_dst); 379 if (optlen + (u_short)ip->ip_len > IP_MAXPACKET) 380 return (m); /* XXX should fail */ 381 if (p->ipopt_dst.s_addr) 382 ip->ip_dst = p->ipopt_dst; 383 if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) { 384 MGETHDR(n, M_DONTWAIT, MT_HEADER); 385 if (n == 0) 386 return (m); 387 n->m_pkthdr.len = m->m_pkthdr.len + optlen; 388 m->m_len -= sizeof(struct ip); 389 m->m_data += sizeof(struct ip); 390 n->m_next = m; 391 m = n; 392 m->m_len = optlen + sizeof(struct ip); 393 m->m_data += max_linkhdr; 394 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 395 } else { 396 m->m_data -= optlen; 397 m->m_len += optlen; 398 m->m_pkthdr.len += optlen; 399 ovbcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 400 } 401 ip = mtod(m, struct ip *); 402 bcopy((caddr_t)p->ipopt_list, (caddr_t)(ip + 1), (unsigned)optlen); 403 *phlen = sizeof(struct ip) + optlen; 404 ip->ip_len += optlen; 405 return (m); 406 } 407 408 /* 409 * Copy options from ip to jp, 410 * omitting those not copied during fragmentation. 411 */ 412 int 413 ip_optcopy(ip, jp) 414 struct ip *ip, *jp; 415 { 416 register u_char *cp, *dp; 417 int opt, optlen, cnt; 418 419 cp = (u_char *)(ip + 1); 420 dp = (u_char *)(jp + 1); 421 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 422 for (; cnt > 0; cnt -= optlen, cp += optlen) { 423 opt = cp[0]; 424 if (opt == IPOPT_EOL) 425 break; 426 if (opt == IPOPT_NOP) 427 optlen = 1; 428 else 429 optlen = cp[IPOPT_OLEN]; 430 /* bogus lengths should have been caught by ip_dooptions */ 431 if (optlen > cnt) 432 optlen = cnt; 433 if (IPOPT_COPIED(opt)) { 434 bcopy((caddr_t)cp, (caddr_t)dp, (unsigned)optlen); 435 dp += optlen; 436 } 437 } 438 for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++) 439 *dp++ = IPOPT_EOL; 440 return (optlen); 441 } 442 443 /* 444 * IP socket option processing. 445 */ 446 int 447 ip_ctloutput(op, so, level, optname, mp) 448 int op; 449 struct socket *so; 450 int level, optname; 451 struct mbuf **mp; 452 { 453 register struct inpcb *inp = sotoinpcb(so); 454 register struct mbuf *m = *mp; 455 register int optval; 456 int error = 0; 457 458 if (level != IPPROTO_IP) 459 goto freeit; 460 else switch (op) { 461 462 case PRCO_SETOPT: 463 switch (optname) { 464 case IP_OPTIONS: 465 #ifdef notyet 466 case IP_RETOPTS: 467 return (ip_pcbopts(optname, &inp->inp_options, m)); 468 #else 469 return (ip_pcbopts(&inp->inp_options, m)); 470 #endif 471 472 case IP_TOS: 473 case IP_TTL: 474 case IP_RECVOPTS: 475 case IP_RECVRETOPTS: 476 case IP_RECVDSTADDR: 477 if (m->m_len != sizeof(int)) 478 error = EINVAL; 479 else { 480 optval = *mtod(m, int *); 481 switch (optname) { 482 483 case IP_TOS: 484 inp->inp_ip.ip_tos = optval; 485 break; 486 487 case IP_TTL: 488 inp->inp_ip.ip_ttl = optval; 489 break; 490 #define OPTSET(bit) \ 491 if (optval) \ 492 inp->inp_flags |= bit; \ 493 else \ 494 inp->inp_flags &= ~bit; 495 496 case IP_RECVOPTS: 497 OPTSET(INP_RECVOPTS); 498 break; 499 500 case IP_RECVRETOPTS: 501 OPTSET(INP_RECVRETOPTS); 502 break; 503 504 case IP_RECVDSTADDR: 505 OPTSET(INP_RECVDSTADDR); 506 break; 507 } 508 } 509 break; 510 #undef OPTSET 511 512 #ifdef MULTICAST 513 case IP_MULTICAST_IF: 514 case IP_MULTICAST_TTL: 515 case IP_MULTICAST_LOOP: 516 case IP_ADD_MEMBERSHIP: 517 case IP_DROP_MEMBERSHIP: 518 error = ip_setmoptions(optname, &inp->inp_moptions, m); 519 break; 520 #endif 521 522 freeit: 523 default: 524 error = EINVAL; 525 break; 526 } 527 if (m) 528 (void)m_free(m); 529 break; 530 531 case PRCO_GETOPT: 532 switch (optname) { 533 case IP_OPTIONS: 534 case IP_RETOPTS: 535 *mp = m = m_get(M_WAIT, MT_SOOPTS); 536 if (inp->inp_options) { 537 m->m_len = inp->inp_options->m_len; 538 bcopy(mtod(inp->inp_options, caddr_t), 539 mtod(m, caddr_t), (unsigned)m->m_len); 540 } else 541 m->m_len = 0; 542 break; 543 544 case IP_TOS: 545 case IP_TTL: 546 case IP_RECVOPTS: 547 case IP_RECVRETOPTS: 548 case IP_RECVDSTADDR: 549 *mp = m = m_get(M_WAIT, MT_SOOPTS); 550 m->m_len = sizeof(int); 551 switch (optname) { 552 553 case IP_TOS: 554 optval = inp->inp_ip.ip_tos; 555 break; 556 557 case IP_TTL: 558 optval = inp->inp_ip.ip_ttl; 559 break; 560 561 #define OPTBIT(bit) (inp->inp_flags & bit ? 1 : 0) 562 563 case IP_RECVOPTS: 564 optval = OPTBIT(INP_RECVOPTS); 565 break; 566 567 case IP_RECVRETOPTS: 568 optval = OPTBIT(INP_RECVRETOPTS); 569 break; 570 571 case IP_RECVDSTADDR: 572 optval = OPTBIT(INP_RECVDSTADDR); 573 break; 574 } 575 *mtod(m, int *) = optval; 576 break; 577 578 #ifdef MULTICAST 579 case IP_MULTICAST_IF: 580 case IP_MULTICAST_TTL: 581 case IP_MULTICAST_LOOP: 582 case IP_ADD_MEMBERSHIP: 583 case IP_DROP_MEMBERSHIP: 584 error = ip_getmoptions(optname, inp->inp_moptions, mp); 585 break; 586 #endif 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 #ifdef MULTICAST 705 /* 706 * Set the IP multicast options in response to user setsockopt(). 707 */ 708 int 709 ip_setmoptions(optname, imop, m) 710 int optname; 711 struct ip_moptions **imop; 712 struct mbuf *m; 713 { 714 register int error = 0; 715 u_char loop; 716 register int i; 717 struct in_addr addr; 718 register struct ip_mreq *mreq; 719 register struct ifnet *ifp; 720 register struct ip_moptions *imo = *imop; 721 struct route ro; 722 register struct sockaddr_in *dst; 723 724 if (imo == NULL) { 725 /* 726 * No multicast option buffer attached to the pcb; 727 * allocate one and initialize to default values. 728 */ 729 imo = (struct ip_moptions*)malloc(sizeof(*imo), M_IPMOPTS, 730 M_WAITOK); 731 732 if (imo == NULL) 733 return (ENOBUFS); 734 *imop = imo; 735 imo->imo_multicast_ifp = NULL; 736 imo->imo_multicast_ttl = IP_DEFAULT_MULTICAST_TTL; 737 imo->imo_multicast_loop = IP_DEFAULT_MULTICAST_LOOP; 738 imo->imo_num_memberships = 0; 739 } 740 741 switch (optname) { 742 743 case IP_MULTICAST_IF: 744 /* 745 * Select the interface for outgoing multicast packets. 746 */ 747 if (m == NULL || m->m_len != sizeof(struct in_addr)) { 748 error = EINVAL; 749 break; 750 } 751 addr = *(mtod(m, struct in_addr *)); 752 /* 753 * INADDR_ANY is used to remove a previous selection. 754 * When no interface is selected, a default one is 755 * chosen every time a multicast packet is sent. 756 */ 757 if (addr.s_addr == INADDR_ANY) { 758 imo->imo_multicast_ifp = NULL; 759 break; 760 } 761 /* 762 * The selected interface is identified by its local 763 * IP address. Find the interface and confirm that 764 * it supports multicasting. 765 */ 766 INADDR_TO_IFP(addr, ifp); 767 if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) { 768 error = EADDRNOTAVAIL; 769 break; 770 } 771 imo->imo_multicast_ifp = ifp; 772 break; 773 774 case IP_MULTICAST_TTL: 775 /* 776 * Set the IP time-to-live for outgoing multicast packets. 777 */ 778 if (m == NULL || m->m_len != 1) { 779 error = EINVAL; 780 break; 781 } 782 imo->imo_multicast_ttl = *(mtod(m, u_char *)); 783 break; 784 785 case IP_MULTICAST_LOOP: 786 /* 787 * Set the loopback flag for outgoing multicast packets. 788 * Must be zero or one. 789 */ 790 if (m == NULL || m->m_len != 1 || 791 (loop = *(mtod(m, u_char *))) > 1) { 792 error = EINVAL; 793 break; 794 } 795 imo->imo_multicast_loop = loop; 796 break; 797 798 case IP_ADD_MEMBERSHIP: 799 /* 800 * Add a multicast group membership. 801 * Group must be a valid IP multicast address. 802 */ 803 if (m == NULL || m->m_len != sizeof(struct ip_mreq)) { 804 error = EINVAL; 805 break; 806 } 807 mreq = mtod(m, struct ip_mreq *); 808 if (!IN_MULTICAST(ntohl(mreq->imr_multiaddr.s_addr))) { 809 error = EINVAL; 810 break; 811 } 812 /* 813 * If no interface address was provided, use the interface of 814 * the route to the given multicast address. 815 */ 816 if (mreq->imr_interface.s_addr == INADDR_ANY) { 817 ro.ro_rt = NULL; 818 dst = (struct sockaddr_in *)&ro.ro_dst; 819 dst->sin_len = sizeof(*dst); 820 dst->sin_family = AF_INET; 821 dst->sin_addr = mreq->imr_multiaddr; 822 rtalloc(&ro); 823 if (ro.ro_rt == NULL) { 824 error = EADDRNOTAVAIL; 825 break; 826 } 827 ifp = ro.ro_rt->rt_ifp; 828 rtfree(ro.ro_rt); 829 } 830 else { 831 INADDR_TO_IFP(mreq->imr_interface, ifp); 832 } 833 /* 834 * See if we found an interface, and confirm that it 835 * supports multicast. 836 */ 837 if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) { 838 error = EADDRNOTAVAIL; 839 break; 840 } 841 /* 842 * See if the membership already exists or if all the 843 * membership slots are full. 844 */ 845 for (i = 0; i < imo->imo_num_memberships; ++i) { 846 if (imo->imo_membership[i]->inm_ifp == ifp && 847 imo->imo_membership[i]->inm_addr.s_addr 848 == mreq->imr_multiaddr.s_addr) 849 break; 850 } 851 if (i < imo->imo_num_memberships) { 852 error = EADDRINUSE; 853 break; 854 } 855 if (i == IP_MAX_MEMBERSHIPS) { 856 error = ETOOMANYREFS; 857 break; 858 } 859 /* 860 * Everything looks good; add a new record to the multicast 861 * address list for the given interface. 862 */ 863 if ((imo->imo_membership[i] = 864 in_addmulti(&mreq->imr_multiaddr, ifp)) == NULL) { 865 error = ENOBUFS; 866 break; 867 } 868 ++imo->imo_num_memberships; 869 break; 870 871 case IP_DROP_MEMBERSHIP: 872 /* 873 * Drop a multicast group membership. 874 * Group must be a valid IP multicast address. 875 */ 876 if (m == NULL || m->m_len != sizeof(struct ip_mreq)) { 877 error = EINVAL; 878 break; 879 } 880 mreq = mtod(m, struct ip_mreq *); 881 if (!IN_MULTICAST(ntohl(mreq->imr_multiaddr.s_addr))) { 882 error = EINVAL; 883 break; 884 } 885 /* 886 * If an interface address was specified, get a pointer 887 * to its ifnet structure. 888 */ 889 if (mreq->imr_interface.s_addr == INADDR_ANY) 890 ifp = NULL; 891 else { 892 INADDR_TO_IFP(mreq->imr_interface, ifp); 893 if (ifp == NULL) { 894 error = EADDRNOTAVAIL; 895 break; 896 } 897 } 898 /* 899 * Find the membership in the membership array. 900 */ 901 for (i = 0; i < imo->imo_num_memberships; ++i) { 902 if ((ifp == NULL || 903 imo->imo_membership[i]->inm_ifp == ifp) && 904 imo->imo_membership[i]->inm_addr.s_addr == 905 mreq->imr_multiaddr.s_addr) 906 break; 907 } 908 if (i == imo->imo_num_memberships) { 909 error = EADDRNOTAVAIL; 910 break; 911 } 912 /* 913 * Give up the multicast address record to which the 914 * membership points. 915 */ 916 in_delmulti(imo->imo_membership[i]); 917 /* 918 * Remove the gap in the membership array. 919 */ 920 for (++i; i < imo->imo_num_memberships; ++i) 921 imo->imo_membership[i-1] = imo->imo_membership[i]; 922 --imo->imo_num_memberships; 923 break; 924 925 default: 926 error = EOPNOTSUPP; 927 break; 928 } 929 930 /* 931 * If all options have default values, no need to keep the mbuf. 932 */ 933 if (imo->imo_multicast_ifp == NULL && 934 imo->imo_multicast_ttl == IP_DEFAULT_MULTICAST_TTL && 935 imo->imo_multicast_loop == IP_DEFAULT_MULTICAST_LOOP && 936 imo->imo_num_memberships == 0) { 937 free(*imop, M_IPMOPTS); 938 *imop = NULL; 939 } 940 941 return (error); 942 } 943 944 /* 945 * Return the IP multicast options in response to user getsockopt(). 946 */ 947 int 948 ip_getmoptions(optname, imo, mp) 949 int optname; 950 register struct ip_moptions *imo; 951 register struct mbuf **mp; 952 { 953 u_char *ttl; 954 u_char *loop; 955 struct in_addr *addr; 956 struct in_ifaddr *ia; 957 958 *mp = m_get(M_WAIT, MT_SOOPTS); 959 960 switch (optname) { 961 962 case IP_MULTICAST_IF: 963 addr = mtod(*mp, struct in_addr *); 964 (*mp)->m_len = sizeof(struct in_addr); 965 if (imo == NULL || imo->imo_multicast_ifp == NULL) 966 addr->s_addr = INADDR_ANY; 967 else { 968 IFP_TO_IA(imo->imo_multicast_ifp, ia); 969 addr->s_addr = (ia == NULL) ? INADDR_ANY 970 : IA_SIN(ia)->sin_addr.s_addr; 971 } 972 return (0); 973 974 case IP_MULTICAST_TTL: 975 ttl = mtod(*mp, u_char *); 976 (*mp)->m_len = 1; 977 *ttl = (imo == NULL) ? IP_DEFAULT_MULTICAST_TTL 978 : imo->imo_multicast_ttl; 979 return (0); 980 981 case IP_MULTICAST_LOOP: 982 loop = mtod(*mp, u_char *); 983 (*mp)->m_len = 1; 984 *loop = (imo == NULL) ? IP_DEFAULT_MULTICAST_LOOP 985 : imo->imo_multicast_loop; 986 return (0); 987 988 default: 989 return (EOPNOTSUPP); 990 } 991 } 992 993 /* 994 * Discard the IP multicast options. 995 */ 996 void 997 ip_freemoptions(imo) 998 register struct ip_moptions *imo; 999 { 1000 register int i; 1001 1002 if (imo != NULL) { 1003 for (i = 0; i < imo->imo_num_memberships; ++i) 1004 in_delmulti(imo->imo_membership[i]); 1005 free(imo, M_IPMOPTS); 1006 } 1007 } 1008 1009 /* 1010 * Routine called from ip_output() to loop back a copy of an IP multicast 1011 * packet to the input queue of a specified interface. Note that this 1012 * calls the output routine of the loopback "driver", but with an interface 1013 * pointer that might NOT be &loif -- easier than replicating that code here. 1014 */ 1015 static void 1016 ip_mloopback(ifp, m, dst) 1017 struct ifnet *ifp; 1018 register struct mbuf *m; 1019 register struct sockaddr_in *dst; 1020 { 1021 register struct ip *ip; 1022 struct mbuf *copym; 1023 1024 copym = m_copy(m, 0, M_COPYALL); 1025 if (copym != NULL) { 1026 /* 1027 * We don't bother to fragment if the IP length is greater 1028 * than the interface's MTU. Can this possibly matter? 1029 */ 1030 ip = mtod(copym, struct ip *); 1031 ip->ip_len = htons((u_short)ip->ip_len); 1032 ip->ip_off = htons((u_short)ip->ip_off); 1033 ip->ip_sum = 0; 1034 ip->ip_sum = in_cksum(copym, ip->ip_hl << 2); 1035 (void) looutput(ifp, copym, (struct sockaddr *)dst); 1036 } 1037 } 1038 #endif 1039