1 /* 2 * Copyright (c) 1982, 1986, 1988, 1990, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 * 7 * @(#)ip_output.c 8.3 (Berkeley) 01/21/94 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 static struct mbuf *ip_insertoptions __P((struct mbuf *, struct mbuf *, int *)); 33 static void ip_mloopback 34 __P((struct ifnet *, struct mbuf *, 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 #define ifatoia(ifa) ((struct in_ifaddr *)(ifa)) 108 #define sintosa(sin) ((struct sockaddr *)(sin)) 109 if (flags & IP_ROUTETOIF) { 110 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == 0 && 111 (ia = ifatoia(ifa_ifwithnet(sintosa(dst)))) == 0) { 112 ipstat.ips_noroute++; 113 error = ENETUNREACH; 114 goto bad; 115 } 116 ifp = ia->ia_ifp; 117 ip->ip_ttl = 1; 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 = ifatoia(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, ifp)) { 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 (void) m_free(m); 317 error = ENOBUFS; /* ??? */ 318 ipstat.ips_odropped++; 319 goto sendorfree; 320 } 321 m->m_pkthdr.len = mhlen + len; 322 m->m_pkthdr.rcvif = (struct ifnet *)0; 323 mhip->ip_off = htons((u_short)mhip->ip_off); 324 mhip->ip_sum = 0; 325 mhip->ip_sum = in_cksum(m, mhlen); 326 *mnext = m; 327 mnext = &m->m_nextpkt; 328 ipstat.ips_ofragments++; 329 } 330 /* 331 * Update first fragment by trimming what's been copied out 332 * and updating header, then send each fragment (in order). 333 */ 334 m = m0; 335 m_adj(m, hlen + firstlen - (u_short)ip->ip_len); 336 m->m_pkthdr.len = hlen + firstlen; 337 ip->ip_len = htons((u_short)m->m_pkthdr.len); 338 ip->ip_off = htons((u_short)(ip->ip_off | IP_MF)); 339 ip->ip_sum = 0; 340 ip->ip_sum = in_cksum(m, hlen); 341 sendorfree: 342 for (m = m0; m; m = m0) { 343 m0 = m->m_nextpkt; 344 m->m_nextpkt = 0; 345 if (error == 0) 346 error = (*ifp->if_output)(ifp, m, 347 (struct sockaddr *)dst, ro->ro_rt); 348 else 349 m_freem(m); 350 } 351 352 if (error == 0) 353 ipstat.ips_fragmented++; 354 } 355 done: 356 if (ro == &iproute && (flags & IP_ROUTETOIF) == 0 && ro->ro_rt) 357 RTFREE(ro->ro_rt); 358 return (error); 359 bad: 360 m_freem(m0); 361 goto done; 362 } 363 364 /* 365 * Insert IP options into preformed packet. 366 * Adjust IP destination as required for IP source routing, 367 * as indicated by a non-zero in_addr at the start of the options. 368 */ 369 static struct mbuf * 370 ip_insertoptions(m, opt, phlen) 371 register struct mbuf *m; 372 struct mbuf *opt; 373 int *phlen; 374 { 375 register struct ipoption *p = mtod(opt, struct ipoption *); 376 struct mbuf *n; 377 register struct ip *ip = mtod(m, struct ip *); 378 unsigned optlen; 379 380 optlen = opt->m_len - sizeof(p->ipopt_dst); 381 if (optlen + (u_short)ip->ip_len > IP_MAXPACKET) 382 return (m); /* XXX should fail */ 383 if (p->ipopt_dst.s_addr) 384 ip->ip_dst = p->ipopt_dst; 385 if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) { 386 MGETHDR(n, M_DONTWAIT, MT_HEADER); 387 if (n == 0) 388 return (m); 389 n->m_pkthdr.len = m->m_pkthdr.len + optlen; 390 m->m_len -= sizeof(struct ip); 391 m->m_data += sizeof(struct ip); 392 n->m_next = m; 393 m = n; 394 m->m_len = optlen + sizeof(struct ip); 395 m->m_data += max_linkhdr; 396 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 397 } else { 398 m->m_data -= optlen; 399 m->m_len += optlen; 400 m->m_pkthdr.len += optlen; 401 ovbcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 402 } 403 ip = mtod(m, struct ip *); 404 bcopy((caddr_t)p->ipopt_list, (caddr_t)(ip + 1), (unsigned)optlen); 405 *phlen = sizeof(struct ip) + optlen; 406 ip->ip_len += optlen; 407 return (m); 408 } 409 410 /* 411 * Copy options from ip to jp, 412 * omitting those not copied during fragmentation. 413 */ 414 int 415 ip_optcopy(ip, jp) 416 struct ip *ip, *jp; 417 { 418 register u_char *cp, *dp; 419 int opt, optlen, cnt; 420 421 cp = (u_char *)(ip + 1); 422 dp = (u_char *)(jp + 1); 423 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 424 for (; cnt > 0; cnt -= optlen, cp += optlen) { 425 opt = cp[0]; 426 if (opt == IPOPT_EOL) 427 break; 428 if (opt == IPOPT_NOP) { 429 /* Preserve for IP mcast tunnel's LSRR alignment. */ 430 *dp++ = IPOPT_NOP; 431 optlen = 1; 432 continue; 433 } else 434 optlen = cp[IPOPT_OLEN]; 435 /* bogus lengths should have been caught by ip_dooptions */ 436 if (optlen > cnt) 437 optlen = cnt; 438 if (IPOPT_COPIED(opt)) { 439 bcopy((caddr_t)cp, (caddr_t)dp, (unsigned)optlen); 440 dp += optlen; 441 } 442 } 443 for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++) 444 *dp++ = IPOPT_EOL; 445 return (optlen); 446 } 447 448 /* 449 * IP socket option processing. 450 */ 451 int 452 ip_ctloutput(op, so, level, optname, mp) 453 int op; 454 struct socket *so; 455 int level, optname; 456 struct mbuf **mp; 457 { 458 register struct inpcb *inp = sotoinpcb(so); 459 register struct mbuf *m = *mp; 460 register int optval; 461 int error = 0; 462 463 if (level != IPPROTO_IP) { 464 error = EINVAL; 465 if (op == PRCO_SETOPT && *mp) 466 (void) m_free(*mp); 467 } else switch (op) { 468 469 case PRCO_SETOPT: 470 switch (optname) { 471 case IP_OPTIONS: 472 #ifdef notyet 473 case IP_RETOPTS: 474 return (ip_pcbopts(optname, &inp->inp_options, m)); 475 #else 476 return (ip_pcbopts(&inp->inp_options, m)); 477 #endif 478 479 case IP_TOS: 480 case IP_TTL: 481 case IP_RECVOPTS: 482 case IP_RECVRETOPTS: 483 case IP_RECVDSTADDR: 484 if (m->m_len != sizeof(int)) 485 error = EINVAL; 486 else { 487 optval = *mtod(m, int *); 488 switch (optname) { 489 490 case IP_TOS: 491 inp->inp_ip.ip_tos = optval; 492 break; 493 494 case IP_TTL: 495 inp->inp_ip.ip_ttl = optval; 496 break; 497 #define OPTSET(bit) \ 498 if (optval) \ 499 inp->inp_flags |= bit; \ 500 else \ 501 inp->inp_flags &= ~bit; 502 503 case IP_RECVOPTS: 504 OPTSET(INP_RECVOPTS); 505 break; 506 507 case IP_RECVRETOPTS: 508 OPTSET(INP_RECVRETOPTS); 509 break; 510 511 case IP_RECVDSTADDR: 512 OPTSET(INP_RECVDSTADDR); 513 break; 514 } 515 } 516 break; 517 #undef OPTSET 518 519 case IP_MULTICAST_IF: 520 case IP_MULTICAST_TTL: 521 case IP_MULTICAST_LOOP: 522 case IP_ADD_MEMBERSHIP: 523 case IP_DROP_MEMBERSHIP: 524 error = ip_setmoptions(optname, &inp->inp_moptions, m); 525 break; 526 527 default: 528 error = ENOPROTOOPT; 529 break; 530 } 531 if (m) 532 (void)m_free(m); 533 break; 534 535 case PRCO_GETOPT: 536 switch (optname) { 537 case IP_OPTIONS: 538 case IP_RETOPTS: 539 *mp = m = m_get(M_WAIT, MT_SOOPTS); 540 if (inp->inp_options) { 541 m->m_len = inp->inp_options->m_len; 542 bcopy(mtod(inp->inp_options, caddr_t), 543 mtod(m, caddr_t), (unsigned)m->m_len); 544 } else 545 m->m_len = 0; 546 break; 547 548 case IP_TOS: 549 case IP_TTL: 550 case IP_RECVOPTS: 551 case IP_RECVRETOPTS: 552 case IP_RECVDSTADDR: 553 *mp = m = m_get(M_WAIT, MT_SOOPTS); 554 m->m_len = sizeof(int); 555 switch (optname) { 556 557 case IP_TOS: 558 optval = inp->inp_ip.ip_tos; 559 break; 560 561 case IP_TTL: 562 optval = inp->inp_ip.ip_ttl; 563 break; 564 565 #define OPTBIT(bit) (inp->inp_flags & bit ? 1 : 0) 566 567 case IP_RECVOPTS: 568 optval = OPTBIT(INP_RECVOPTS); 569 break; 570 571 case IP_RECVRETOPTS: 572 optval = OPTBIT(INP_RECVRETOPTS); 573 break; 574 575 case IP_RECVDSTADDR: 576 optval = OPTBIT(INP_RECVDSTADDR); 577 break; 578 } 579 *mtod(m, int *) = optval; 580 break; 581 582 case IP_MULTICAST_IF: 583 case IP_MULTICAST_TTL: 584 case IP_MULTICAST_LOOP: 585 case IP_ADD_MEMBERSHIP: 586 case IP_DROP_MEMBERSHIP: 587 error = ip_getmoptions(optname, inp->inp_moptions, mp); 588 break; 589 590 default: 591 error = ENOPROTOOPT; 592 break; 593 } 594 break; 595 } 596 return (error); 597 } 598 599 /* 600 * Set up IP options in pcb for insertion in output packets. 601 * Store in mbuf with pointer in pcbopt, adding pseudo-option 602 * with destination address if source routed. 603 */ 604 int 605 #ifdef notyet 606 ip_pcbopts(optname, pcbopt, m) 607 int optname; 608 #else 609 ip_pcbopts(pcbopt, m) 610 #endif 611 struct mbuf **pcbopt; 612 register struct mbuf *m; 613 { 614 register cnt, optlen; 615 register u_char *cp; 616 u_char opt; 617 618 /* turn off any old options */ 619 if (*pcbopt) 620 (void)m_free(*pcbopt); 621 *pcbopt = 0; 622 if (m == (struct mbuf *)0 || m->m_len == 0) { 623 /* 624 * Only turning off any previous options. 625 */ 626 if (m) 627 (void)m_free(m); 628 return (0); 629 } 630 631 #ifndef vax 632 if (m->m_len % sizeof(long)) 633 goto bad; 634 #endif 635 /* 636 * IP first-hop destination address will be stored before 637 * actual options; move other options back 638 * and clear it when none present. 639 */ 640 if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN]) 641 goto bad; 642 cnt = m->m_len; 643 m->m_len += sizeof(struct in_addr); 644 cp = mtod(m, u_char *) + sizeof(struct in_addr); 645 ovbcopy(mtod(m, caddr_t), (caddr_t)cp, (unsigned)cnt); 646 bzero(mtod(m, caddr_t), sizeof(struct in_addr)); 647 648 for (; cnt > 0; cnt -= optlen, cp += optlen) { 649 opt = cp[IPOPT_OPTVAL]; 650 if (opt == IPOPT_EOL) 651 break; 652 if (opt == IPOPT_NOP) 653 optlen = 1; 654 else { 655 optlen = cp[IPOPT_OLEN]; 656 if (optlen <= IPOPT_OLEN || optlen > cnt) 657 goto bad; 658 } 659 switch (opt) { 660 661 default: 662 break; 663 664 case IPOPT_LSRR: 665 case IPOPT_SSRR: 666 /* 667 * user process specifies route as: 668 * ->A->B->C->D 669 * D must be our final destination (but we can't 670 * check that since we may not have connected yet). 671 * A is first hop destination, which doesn't appear in 672 * actual IP option, but is stored before the options. 673 */ 674 if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr)) 675 goto bad; 676 m->m_len -= sizeof(struct in_addr); 677 cnt -= sizeof(struct in_addr); 678 optlen -= sizeof(struct in_addr); 679 cp[IPOPT_OLEN] = optlen; 680 /* 681 * Move first hop before start of options. 682 */ 683 bcopy((caddr_t)&cp[IPOPT_OFFSET+1], mtod(m, caddr_t), 684 sizeof(struct in_addr)); 685 /* 686 * Then copy rest of options back 687 * to close up the deleted entry. 688 */ 689 ovbcopy((caddr_t)(&cp[IPOPT_OFFSET+1] + 690 sizeof(struct in_addr)), 691 (caddr_t)&cp[IPOPT_OFFSET+1], 692 (unsigned)cnt + sizeof(struct in_addr)); 693 break; 694 } 695 } 696 if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr)) 697 goto bad; 698 *pcbopt = m; 699 return (0); 700 701 bad: 702 (void)m_free(m); 703 return (EINVAL); 704 } 705 706 /* 707 * Set the IP multicast options in response to user setsockopt(). 708 */ 709 int 710 ip_setmoptions(optname, imop, m) 711 int optname; 712 struct ip_moptions **imop; 713 struct mbuf *m; 714 { 715 register int error = 0; 716 u_char loop; 717 register int i; 718 struct in_addr addr; 719 register struct ip_mreq *mreq; 720 register struct ifnet *ifp; 721 register struct ip_moptions *imo = *imop; 722 struct route ro; 723 register struct sockaddr_in *dst; 724 725 if (imo == NULL) { 726 /* 727 * No multicast option buffer attached to the pcb; 728 * allocate one and initialize to default values. 729 */ 730 imo = (struct ip_moptions*)malloc(sizeof(*imo), M_IPMOPTS, 731 M_WAITOK); 732 733 if (imo == NULL) 734 return (ENOBUFS); 735 *imop = imo; 736 imo->imo_multicast_ifp = NULL; 737 imo->imo_multicast_ttl = IP_DEFAULT_MULTICAST_TTL; 738 imo->imo_multicast_loop = IP_DEFAULT_MULTICAST_LOOP; 739 imo->imo_num_memberships = 0; 740 } 741 742 switch (optname) { 743 744 case IP_MULTICAST_IF: 745 /* 746 * Select the interface for outgoing multicast packets. 747 */ 748 if (m == NULL || m->m_len != sizeof(struct in_addr)) { 749 error = EINVAL; 750 break; 751 } 752 addr = *(mtod(m, struct in_addr *)); 753 /* 754 * INADDR_ANY is used to remove a previous selection. 755 * When no interface is selected, a default one is 756 * chosen every time a multicast packet is sent. 757 */ 758 if (addr.s_addr == INADDR_ANY) { 759 imo->imo_multicast_ifp = NULL; 760 break; 761 } 762 /* 763 * The selected interface is identified by its local 764 * IP address. Find the interface and confirm that 765 * it supports multicasting. 766 */ 767 INADDR_TO_IFP(addr, ifp); 768 if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) { 769 error = EADDRNOTAVAIL; 770 break; 771 } 772 imo->imo_multicast_ifp = ifp; 773 break; 774 775 case IP_MULTICAST_TTL: 776 /* 777 * Set the IP time-to-live for outgoing multicast packets. 778 */ 779 if (m == NULL || m->m_len != 1) { 780 error = EINVAL; 781 break; 782 } 783 imo->imo_multicast_ttl = *(mtod(m, u_char *)); 784 break; 785 786 case IP_MULTICAST_LOOP: 787 /* 788 * Set the loopback flag for outgoing multicast packets. 789 * Must be zero or one. 790 */ 791 if (m == NULL || m->m_len != 1 || 792 (loop = *(mtod(m, u_char *))) > 1) { 793 error = EINVAL; 794 break; 795 } 796 imo->imo_multicast_loop = loop; 797 break; 798 799 case IP_ADD_MEMBERSHIP: 800 /* 801 * Add a multicast group membership. 802 * Group must be a valid IP multicast address. 803 */ 804 if (m == NULL || m->m_len != sizeof(struct ip_mreq)) { 805 error = EINVAL; 806 break; 807 } 808 mreq = mtod(m, struct ip_mreq *); 809 if (!IN_MULTICAST(ntohl(mreq->imr_multiaddr.s_addr))) { 810 error = EINVAL; 811 break; 812 } 813 /* 814 * If no interface address was provided, use the interface of 815 * the route to the given multicast address. 816 */ 817 if (mreq->imr_interface.s_addr == INADDR_ANY) { 818 ro.ro_rt = NULL; 819 dst = (struct sockaddr_in *)&ro.ro_dst; 820 dst->sin_len = sizeof(*dst); 821 dst->sin_family = AF_INET; 822 dst->sin_addr = mreq->imr_multiaddr; 823 rtalloc(&ro); 824 if (ro.ro_rt == NULL) { 825 error = EADDRNOTAVAIL; 826 break; 827 } 828 ifp = ro.ro_rt->rt_ifp; 829 rtfree(ro.ro_rt); 830 } 831 else { 832 INADDR_TO_IFP(mreq->imr_interface, ifp); 833 } 834 /* 835 * See if we found an interface, and confirm that it 836 * supports multicast. 837 */ 838 if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) { 839 error = EADDRNOTAVAIL; 840 break; 841 } 842 /* 843 * See if the membership already exists or if all the 844 * membership slots are full. 845 */ 846 for (i = 0; i < imo->imo_num_memberships; ++i) { 847 if (imo->imo_membership[i]->inm_ifp == ifp && 848 imo->imo_membership[i]->inm_addr.s_addr 849 == mreq->imr_multiaddr.s_addr) 850 break; 851 } 852 if (i < imo->imo_num_memberships) { 853 error = EADDRINUSE; 854 break; 855 } 856 if (i == IP_MAX_MEMBERSHIPS) { 857 error = ETOOMANYREFS; 858 break; 859 } 860 /* 861 * Everything looks good; add a new record to the multicast 862 * address list for the given interface. 863 */ 864 if ((imo->imo_membership[i] = 865 in_addmulti(&mreq->imr_multiaddr, ifp)) == NULL) { 866 error = ENOBUFS; 867 break; 868 } 869 ++imo->imo_num_memberships; 870 break; 871 872 case IP_DROP_MEMBERSHIP: 873 /* 874 * Drop a multicast group membership. 875 * Group must be a valid IP multicast address. 876 */ 877 if (m == NULL || m->m_len != sizeof(struct ip_mreq)) { 878 error = EINVAL; 879 break; 880 } 881 mreq = mtod(m, struct ip_mreq *); 882 if (!IN_MULTICAST(ntohl(mreq->imr_multiaddr.s_addr))) { 883 error = EINVAL; 884 break; 885 } 886 /* 887 * If an interface address was specified, get a pointer 888 * to its ifnet structure. 889 */ 890 if (mreq->imr_interface.s_addr == INADDR_ANY) 891 ifp = NULL; 892 else { 893 INADDR_TO_IFP(mreq->imr_interface, ifp); 894 if (ifp == NULL) { 895 error = EADDRNOTAVAIL; 896 break; 897 } 898 } 899 /* 900 * Find the membership in the membership array. 901 */ 902 for (i = 0; i < imo->imo_num_memberships; ++i) { 903 if ((ifp == NULL || 904 imo->imo_membership[i]->inm_ifp == ifp) && 905 imo->imo_membership[i]->inm_addr.s_addr == 906 mreq->imr_multiaddr.s_addr) 907 break; 908 } 909 if (i == imo->imo_num_memberships) { 910 error = EADDRNOTAVAIL; 911 break; 912 } 913 /* 914 * Give up the multicast address record to which the 915 * membership points. 916 */ 917 in_delmulti(imo->imo_membership[i]); 918 /* 919 * Remove the gap in the membership array. 920 */ 921 for (++i; i < imo->imo_num_memberships; ++i) 922 imo->imo_membership[i-1] = imo->imo_membership[i]; 923 --imo->imo_num_memberships; 924 break; 925 926 default: 927 error = EOPNOTSUPP; 928 break; 929 } 930 931 /* 932 * If all options have default values, no need to keep the mbuf. 933 */ 934 if (imo->imo_multicast_ifp == NULL && 935 imo->imo_multicast_ttl == IP_DEFAULT_MULTICAST_TTL && 936 imo->imo_multicast_loop == IP_DEFAULT_MULTICAST_LOOP && 937 imo->imo_num_memberships == 0) { 938 free(*imop, M_IPMOPTS); 939 *imop = NULL; 940 } 941 942 return (error); 943 } 944 945 /* 946 * Return the IP multicast options in response to user getsockopt(). 947 */ 948 int 949 ip_getmoptions(optname, imo, mp) 950 int optname; 951 register struct ip_moptions *imo; 952 register struct mbuf **mp; 953 { 954 u_char *ttl; 955 u_char *loop; 956 struct in_addr *addr; 957 struct in_ifaddr *ia; 958 959 *mp = m_get(M_WAIT, MT_SOOPTS); 960 961 switch (optname) { 962 963 case IP_MULTICAST_IF: 964 addr = mtod(*mp, struct in_addr *); 965 (*mp)->m_len = sizeof(struct in_addr); 966 if (imo == NULL || imo->imo_multicast_ifp == NULL) 967 addr->s_addr = INADDR_ANY; 968 else { 969 IFP_TO_IA(imo->imo_multicast_ifp, ia); 970 addr->s_addr = (ia == NULL) ? INADDR_ANY 971 : IA_SIN(ia)->sin_addr.s_addr; 972 } 973 return (0); 974 975 case IP_MULTICAST_TTL: 976 ttl = mtod(*mp, u_char *); 977 (*mp)->m_len = 1; 978 *ttl = (imo == NULL) ? IP_DEFAULT_MULTICAST_TTL 979 : imo->imo_multicast_ttl; 980 return (0); 981 982 case IP_MULTICAST_LOOP: 983 loop = mtod(*mp, u_char *); 984 (*mp)->m_len = 1; 985 *loop = (imo == NULL) ? IP_DEFAULT_MULTICAST_LOOP 986 : imo->imo_multicast_loop; 987 return (0); 988 989 default: 990 return (EOPNOTSUPP); 991 } 992 } 993 994 /* 995 * Discard the IP multicast options. 996 */ 997 void 998 ip_freemoptions(imo) 999 register struct ip_moptions *imo; 1000 { 1001 register int i; 1002 1003 if (imo != NULL) { 1004 for (i = 0; i < imo->imo_num_memberships; ++i) 1005 in_delmulti(imo->imo_membership[i]); 1006 free(imo, M_IPMOPTS); 1007 } 1008 } 1009 1010 /* 1011 * Routine called from ip_output() to loop back a copy of an IP multicast 1012 * packet to the input queue of a specified interface. Note that this 1013 * calls the output routine of the loopback "driver", but with an interface 1014 * pointer that might NOT be &loif -- easier than replicating that code here. 1015 */ 1016 static void 1017 ip_mloopback(ifp, m, dst) 1018 struct ifnet *ifp; 1019 register struct mbuf *m; 1020 register struct sockaddr_in *dst; 1021 { 1022 register struct ip *ip; 1023 struct mbuf *copym; 1024 1025 copym = m_copy(m, 0, M_COPYALL); 1026 if (copym != NULL) { 1027 /* 1028 * We don't bother to fragment if the IP length is greater 1029 * than the interface's MTU. Can this possibly matter? 1030 */ 1031 ip = mtod(copym, struct ip *); 1032 ip->ip_len = htons((u_short)ip->ip_len); 1033 ip->ip_off = htons((u_short)ip->ip_off); 1034 ip->ip_sum = 0; 1035 ip->ip_sum = in_cksum(copym, ip->ip_hl << 2); 1036 (void) looutput(ifp, copym, (struct sockaddr *)dst, NULL); 1037 } 1038 } 1039