sys/netinet/ip_output.c

   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  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  *      @(#)ip_output.c 8.3 (Berkeley) 1/21/94
  30  * $FreeBSD$
  31  */
  32
  33 #include "opt_ipfw.h"
  34 #include "opt_ipsec.h"
  35 #include "opt_mac.h"
  36 #include "opt_mbuf_stress_test.h"
  37
  38 #include <sys/param.h>
  39 #include <sys/systm.h>
  40 #include <sys/kernel.h>
  41 #include <sys/mac.h>
  42 #include <sys/malloc.h>
  43 #include <sys/mbuf.h>
  44 #include <sys/protosw.h>
  45 #include <sys/socket.h>
  46 #include <sys/socketvar.h>
  47 #include <sys/sysctl.h>
  48
  49 #include <net/if.h>
  50 #include <net/netisr.h>
  51 #include <net/pfil.h>
  52 #include <net/route.h>
  53
  54 #include <netinet/in.h>
  55 #include <netinet/in_systm.h>
  56 #include <netinet/ip.h>
  57 #include <netinet/in_pcb.h>
  58 #include <netinet/in_var.h>
  59 #include <netinet/ip_var.h>
  60 #include <netinet/ip_options.h>
  61
  62 #if defined(IPSEC) || defined(FAST_IPSEC)
  63 #include <netinet/ip_ipsec.h>
  64 #ifdef IPSEC
  65 #include <netinet6/ipsec.h>
  66 #endif
  67 #ifdef FAST_IPSEC
  68 #include <netipsec/ipsec.h>
  69 #endif
  70 #endif /*IPSEC*/
  71
  72 #include <machine/in_cksum.h>
  73
  74 static MALLOC_DEFINE(M_IPMOPTS, "ip_moptions", "internet multicast options");
  75
  76 #define print_ip(x, a, y)        printf("%s %d.%d.%d.%d%s",\
  77                                 x, (ntohl(a.s_addr)>>24)&0xFF,\
  78                                   (ntohl(a.s_addr)>>16)&0xFF,\
  79                                   (ntohl(a.s_addr)>>8)&0xFF,\
  80                                   (ntohl(a.s_addr))&0xFF, y);
  81
  82 u_short ip_id;
  83
  84 #ifdef MBUF_STRESS_TEST
  85 int mbuf_frag_size = 0;
  86 SYSCTL_INT(_net_inet_ip, OID_AUTO, mbuf_frag_size, CTLFLAG_RW,
  87         &mbuf_frag_size, 0, "Fragment outgoing mbufs to this size");
  88 #endif
  89
  90 static struct ifnet *ip_multicast_if(struct in_addr *, int *);
  91 static void     ip_mloopback
  92         (struct ifnet *, struct mbuf *, struct sockaddr_in *, int);
  93 static int      ip_getmoptions(struct inpcb *, struct sockopt *);
  94 static int      ip_setmoptions(struct inpcb *, struct sockopt *);
  95
  96
  97 extern  struct protosw inetsw[];
  98
  99 /*
 100  * IP output.  The packet in mbuf chain m contains a skeletal IP
 101  * header (with len, off, ttl, proto, tos, src, dst).
 102  * The mbuf chain containing the packet will be freed.
 103  * The mbuf opt, if present, will not be freed.
 104  * In the IP forwarding case, the packet will arrive with options already
 105  * inserted, so must have a NULL opt pointer.
 106  */
 107 int
 108 ip_output(struct mbuf *m, struct mbuf *opt, struct route *ro,
 109         int flags, struct ip_moptions *imo, struct inpcb *inp)
 110 {
 111         struct ip *ip;
 112         struct ifnet *ifp = NULL;       /* keep compiler happy */
 113         struct mbuf *m0;
 114         int hlen = sizeof (struct ip);
 115         int len, error = 0;
 116         struct sockaddr_in *dst = NULL; /* keep compiler happy */
 117         struct in_ifaddr *ia = NULL;
 118         int isbroadcast, sw_csum;
 119         struct route iproute;
 120         struct in_addr odst;
 121 #ifdef IPFIREWALL_FORWARD
 122         struct m_tag *fwd_tag = NULL;
 123 #endif
 124         M_ASSERTPKTHDR(m);
 125
 126         if (ro == NULL) {
 127                 ro = &iproute;
 128                 bzero(ro, sizeof (*ro));
 129         }
 130
 131         if (inp != NULL)
 132                 INP_LOCK_ASSERT(inp);
 133
 134         if (opt) {
 135                 len = 0;
 136                 m = ip_insertoptions(m, opt, &len);
 137                 if (len != 0)
 138                         hlen = len;
 139         }
 140         ip = mtod(m, struct ip *);
 141
 142         /*
 143          * Fill in IP header.  If we are not allowing fragmentation,
 144          * then the ip_id field is meaningless, but we don't set it
 145          * to zero.  Doing so causes various problems when devices along
 146          * the path (routers, load balancers, firewalls, etc.) illegally
 147          * disable DF on our packet.  Note that a 16-bit counter
 148          * will wrap around in less than 10 seconds at 100 Mbit/s on a
 149          * medium with MTU 1500.  See Steven M. Bellovin, "A Technique
 150          * for Counting NATted Hosts", Proc. IMW'02, available at
 151          * <http://www.research.att.com/~smb/papers/fnat.pdf>.
 152          */
 153         if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) {
 154                 ip->ip_v = IPVERSION;
 155                 ip->ip_hl = hlen >> 2;
 156                 ip->ip_id = ip_newid();
 157                 ipstat.ips_localout++;
 158         } else {
 159                 hlen = ip->ip_hl << 2;
 160         }
 161
 162         dst = (struct sockaddr_in *)&ro->ro_dst;
 163 again:
 164         /*
 165          * If there is a cached route,
 166          * check that it is to the same destination
 167          * and is still up.  If not, free it and try again.
 168          * The address family should also be checked in case of sharing the
 169          * cache with IPv6.
 170          */
 171         if (ro->ro_rt && ((ro->ro_rt->rt_flags & RTF_UP) == 0 ||
 172                           dst->sin_family != AF_INET ||
 173                           dst->sin_addr.s_addr != ip->ip_dst.s_addr)) {
 174                 RTFREE(ro->ro_rt);
 175                 ro->ro_rt = (struct rtentry *)0;
 176         }
 177 #ifdef IPFIREWALL_FORWARD
 178         if (ro->ro_rt == NULL && fwd_tag == NULL) {
 179 #else
 180         if (ro->ro_rt == NULL) {
 181 #endif
 182                 bzero(dst, sizeof(*dst));
 183                 dst->sin_family = AF_INET;
 184                 dst->sin_len = sizeof(*dst);
 185                 dst->sin_addr = ip->ip_dst;
 186         }
 187         /*
 188          * If routing to interface only,
 189          * short circuit routing lookup.
 190          */
 191         if (flags & IP_ROUTETOIF) {
 192                 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL &&
 193                     (ia = ifatoia(ifa_ifwithnet(sintosa(dst)))) == NULL) {
 194                         ipstat.ips_noroute++;
 195                         error = ENETUNREACH;
 196                         goto bad;
 197                 }
 198                 ifp = ia->ia_ifp;
 199                 ip->ip_ttl = 1;
 200                 isbroadcast = in_broadcast(dst->sin_addr, ifp);
 201         } else if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) &&
 202             imo != NULL && imo->imo_multicast_ifp != NULL) {
 203                 /*
 204                  * Bypass the normal routing lookup for multicast
 205                  * packets if the interface is specified.
 206                  */
 207                 ifp = imo->imo_multicast_ifp;
 208                 IFP_TO_IA(ifp, ia);
 209                 isbroadcast = 0;        /* fool gcc */
 210         } else {
 211                 /*
 212                  * We want to do any cloning requested by the link layer,
 213                  * as this is probably required in all cases for correct
 214                  * operation (as it is for ARP).
 215                  */
 216                 if (ro->ro_rt == NULL)
 217                         rtalloc_ign(ro, 0);
 218                 if (ro->ro_rt == NULL) {
 219                         ipstat.ips_noroute++;
 220                         error = EHOSTUNREACH;
 221                         goto bad;
 222                 }
 223                 ia = ifatoia(ro->ro_rt->rt_ifa);
 224                 ifp = ro->ro_rt->rt_ifp;
 225                 ro->ro_rt->rt_rmx.rmx_pksent++;
 226                 if (ro->ro_rt->rt_flags & RTF_GATEWAY)
 227                         dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway;
 228                 if (ro->ro_rt->rt_flags & RTF_HOST)
 229                         isbroadcast = (ro->ro_rt->rt_flags & RTF_BROADCAST);
 230                 else
 231                         isbroadcast = in_broadcast(dst->sin_addr, ifp);
 232         }
 233         if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
 234                 struct in_multi *inm;
 235
 236                 m->m_flags |= M_MCAST;
 237                 /*
 238                  * IP destination address is multicast.  Make sure "dst"
 239                  * still points to the address in "ro".  (It may have been
 240                  * changed to point to a gateway address, above.)
 241                  */
 242                 dst = (struct sockaddr_in *)&ro->ro_dst;
 243                 /*
 244                  * See if the caller provided any multicast options
 245                  */
 246                 if (imo != NULL) {
 247                         ip->ip_ttl = imo->imo_multicast_ttl;
 248                         if (imo->imo_multicast_vif != -1)
 249                                 ip->ip_src.s_addr =
 250                                     ip_mcast_src ?
 251                                     ip_mcast_src(imo->imo_multicast_vif) :
 252                                     INADDR_ANY;
 253                 } else
 254                         ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL;
 255                 /*
 256                  * Confirm that the outgoing interface supports multicast.
 257                  */
 258                 if ((imo == NULL) || (imo->imo_multicast_vif == -1)) {
 259                         if ((ifp->if_flags & IFF_MULTICAST) == 0) {
 260                                 ipstat.ips_noroute++;
 261                                 error = ENETUNREACH;
 262                                 goto bad;
 263                         }
 264                 }
 265                 /*
 266                  * If source address not specified yet, use address
 267                  * of outgoing interface.
 268                  */
 269                 if (ip->ip_src.s_addr == INADDR_ANY) {
 270                         /* Interface may have no addresses. */
 271                         if (ia != NULL)
 272                                 ip->ip_src = IA_SIN(ia)->sin_addr;
 273                 }
 274
 275                 IN_MULTI_LOCK();
 276                 IN_LOOKUP_MULTI(ip->ip_dst, ifp, inm);
 277                 if (inm != NULL &&
 278                    (imo == NULL || imo->imo_multicast_loop)) {
 279                         IN_MULTI_UNLOCK();
 280                         /*
 281                          * If we belong to the destination multicast group
 282                          * on the outgoing interface, and the caller did not
 283                          * forbid loopback, loop back a copy.
 284                          */
 285                         ip_mloopback(ifp, m, dst, hlen);
 286                 }
 287                 else {
 288                         IN_MULTI_UNLOCK();
 289                         /*
 290                          * If we are acting as a multicast router, perform
 291                          * multicast forwarding as if the packet had just
 292                          * arrived on the interface to which we are about
 293                          * to send.  The multicast forwarding function
 294                          * recursively calls this function, using the
 295                          * IP_FORWARDING flag to prevent infinite recursion.
 296                          *
 297                          * Multicasts that are looped back by ip_mloopback(),
 298                          * above, will be forwarded by the ip_input() routine,
 299                          * if necessary.
 300                          */
 301                         if (ip_mrouter && (flags & IP_FORWARDING) == 0) {
 302                                 /*
 303                                  * If rsvp daemon is not running, do not
 304                                  * set ip_moptions. This ensures that the packet
 305                                  * is multicast and not just sent down one link
 306                                  * as prescribed by rsvpd.
 307                                  */
 308                                 if (!rsvp_on)
 309                                         imo = NULL;
 310                                 if (ip_mforward &&
 311                                     ip_mforward(ip, ifp, m, imo) != 0) {
 312                                         m_freem(m);
 313                                         goto done;
 314                                 }
 315                         }
 316                 }
 317
 318                 /*
 319                  * Multicasts with a time-to-live of zero may be looped-
 320                  * back, above, but must not be transmitted on a network.
 321                  * Also, multicasts addressed to the loopback interface
 322                  * are not sent -- the above call to ip_mloopback() will
 323                  * loop back a copy if this host actually belongs to the
 324                  * destination group on the loopback interface.
 325                  */
 326                 if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) {
 327                         m_freem(m);
 328                         goto done;
 329                 }
 330
 331                 goto sendit;
 332         }
 333 #ifndef notdef
 334         /*
 335          * If the source address is not specified yet, use the address
 336          * of the outoing interface.
 337          */
 338         if (ip->ip_src.s_addr == INADDR_ANY) {
 339                 /* Interface may have no addresses. */
 340                 if (ia != NULL) {
 341                         ip->ip_src = IA_SIN(ia)->sin_addr;
 342                 }
 343         }
 344 #endif /* notdef */
 345         /*
 346          * Verify that we have any chance at all of being able to queue the
 347          * packet or packet fragments, unless ALTQ is enabled on the given
 348          * interface in which case packetdrop should be done by queueing.
 349          */
 350 #ifdef ALTQ
 351         if ((!ALTQ_IS_ENABLED(&ifp->if_snd)) &&
 352             ((ifp->if_snd.ifq_len + ip->ip_len / ifp->if_mtu + 1) >=
 353             ifp->if_snd.ifq_maxlen))
 354 #else
 355         if ((ifp->if_snd.ifq_len + ip->ip_len / ifp->if_mtu + 1) >=
 356             ifp->if_snd.ifq_maxlen)
 357 #endif /* ALTQ */
 358         {
 359                 error = ENOBUFS;
 360                 ipstat.ips_odropped++;
 361                 ifp->if_snd.ifq_drops += (ip->ip_len / ifp->if_mtu + 1);
 362                 goto bad;
 363         }
 364
 365         /*
 366          * Look for broadcast address and
 367          * verify user is allowed to send
 368          * such a packet.
 369          */
 370         if (isbroadcast) {
 371                 if ((ifp->if_flags & IFF_BROADCAST) == 0) {
 372                         error = EADDRNOTAVAIL;
 373                         goto bad;
 374                 }
 375                 if ((flags & IP_ALLOWBROADCAST) == 0) {
 376                         error = EACCES;
 377                         goto bad;
 378                 }
 379                 /* don't allow broadcast messages to be fragmented */
 380                 if (ip->ip_len > ifp->if_mtu) {
 381                         error = EMSGSIZE;
 382                         goto bad;
 383                 }
 384                 if (flags & IP_SENDONES)
 385                         ip->ip_dst.s_addr = INADDR_BROADCAST;
 386                 m->m_flags |= M_BCAST;
 387         } else {
 388                 m->m_flags &= ~M_BCAST;
 389         }
 390
 391 sendit:
 392 #if defined(IPSEC) || defined(FAST_IPSEC)
 393         switch(ip_ipsec_output(&m, inp, &flags, &error, &ro, &iproute, &dst, &ia, &ifp)) {
 394         case 1:
 395                 goto bad;
 396         case -1:
 397                 goto done;
 398         case 0:
 399         default:
 400                 break;  /* Continue with packet processing. */
 401         }
 402         /* Update variables that are affected by ipsec4_output(). */
 403         ip = mtod(m, struct ip *);
 404         hlen = ip->ip_hl << 2;
 405 #endif /* IPSEC */
 406
 407         /* Jump over all PFIL processing if hooks are not active. */
 408         if (!PFIL_HOOKED(&inet_pfil_hook))
 409                 goto passout;
 410
 411         /* Run through list of hooks for output packets. */
 412         odst.s_addr = ip->ip_dst.s_addr;
 413         error = pfil_run_hooks(&inet_pfil_hook, &m, ifp, PFIL_OUT, inp);
 414         if (error != 0 || m == NULL)
 415                 goto done;
 416
 417         ip = mtod(m, struct ip *);
 418
 419         /* See if destination IP address was changed by packet filter. */
 420         if (odst.s_addr != ip->ip_dst.s_addr) {
 421                 m->m_flags |= M_SKIP_FIREWALL;
 422                 /* If destination is now ourself drop to ip_input(). */
 423                 if (in_localip(ip->ip_dst)) {
 424                         m->m_flags |= M_FASTFWD_OURS;
 425                         if (m->m_pkthdr.rcvif == NULL)
 426                                 m->m_pkthdr.rcvif = loif;
 427                         if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 428                                 m->m_pkthdr.csum_flags |=
 429                                     CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
 430                                 m->m_pkthdr.csum_data = 0xffff;
 431                         }
 432                         m->m_pkthdr.csum_flags |=
 433                             CSUM_IP_CHECKED | CSUM_IP_VALID;
 434
 435                         error = netisr_queue(NETISR_IP, m);
 436                         goto done;
 437                 } else
 438                         goto again;     /* Redo the routing table lookup. */
 439         }
 440
 441 #ifdef IPFIREWALL_FORWARD
 442         /* See if local, if yes, send it to netisr with IP_FASTFWD_OURS. */
 443         if (m->m_flags & M_FASTFWD_OURS) {
 444                 if (m->m_pkthdr.rcvif == NULL)
 445                         m->m_pkthdr.rcvif = loif;
 446                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 447                         m->m_pkthdr.csum_flags |=
 448                             CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
 449                         m->m_pkthdr.csum_data = 0xffff;
 450                 }
 451                 m->m_pkthdr.csum_flags |=
 452                             CSUM_IP_CHECKED | CSUM_IP_VALID;
 453
 454                 error = netisr_queue(NETISR_IP, m);
 455                 goto done;
 456         }
 457         /* Or forward to some other address? */
 458         fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
 459         if (fwd_tag) {
 460 #ifndef IPFIREWALL_FORWARD_EXTENDED
 461                 if (!in_localip(ip->ip_src) && !in_localaddr(ip->ip_dst)) {
 462 #endif
 463                         dst = (struct sockaddr_in *)&ro->ro_dst;
 464                         bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in));
 465                         m->m_flags |= M_SKIP_FIREWALL;
 466                         m_tag_delete(m, fwd_tag);
 467                         goto again;
 468 #ifndef IPFIREWALL_FORWARD_EXTENDED
 469                 } else {
 470                         m_tag_delete(m, fwd_tag);
 471                         /* Continue. */
 472                 }
 473 #endif
 474         }
 475 #endif /* IPFIREWALL_FORWARD */
 476
 477 passout:
 478         /* 127/8 must not appear on wire - RFC1122. */
 479         if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
 480             (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
 481                 if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
 482                         ipstat.ips_badaddr++;
 483                         error = EADDRNOTAVAIL;
 484                         goto bad;
 485                 }
 486         }
 487
 488         m->m_pkthdr.csum_flags |= CSUM_IP;
 489         sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_hwassist;
 490         if (sw_csum & CSUM_DELAY_DATA) {
 491                 in_delayed_cksum(m);
 492                 sw_csum &= ~CSUM_DELAY_DATA;
 493         }
 494         m->m_pkthdr.csum_flags &= ifp->if_hwassist;
 495
 496         /*
 497          * If small enough for interface, or the interface will take
 498          * care of the fragmentation for us, can just send directly.
 499          */
 500         if (ip->ip_len <= ifp->if_mtu || (ifp->if_hwassist & CSUM_FRAGMENT &&
 501             ((ip->ip_off & IP_DF) == 0))) {
 502                 ip->ip_len = htons(ip->ip_len);
 503                 ip->ip_off = htons(ip->ip_off);
 504                 ip->ip_sum = 0;
 505                 if (sw_csum & CSUM_DELAY_IP)
 506                         ip->ip_sum = in_cksum(m, hlen);
 507
 508                 /* Record statistics for this interface address. */
 509                 if (!(flags & IP_FORWARDING) && ia) {
 510                         ia->ia_ifa.if_opackets++;
 511                         ia->ia_ifa.if_obytes += m->m_pkthdr.len;
 512                 }
 513 #ifdef IPSEC
 514                 /* clean ipsec history once it goes out of the node */
 515                 ipsec_delaux(m);
 516 #endif
 517 #ifdef MBUF_STRESS_TEST
 518                 if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size)
 519                         m = m_fragment(m, M_DONTWAIT, mbuf_frag_size);
 520 #endif
 521                 /*
 522                  * Reset layer specific mbuf flags
 523                  * to avoid confusing lower layers.
 524                  */
 525                 m->m_flags &= ~(M_PROTOFLAGS);
 526
 527                 error = (*ifp->if_output)(ifp, m,
 528                                 (struct sockaddr *)dst, ro->ro_rt);
 529                 goto done;
 530         }
 531
 532         if (ip->ip_off & IP_DF) {
 533                 error = EMSGSIZE;
 534                 /*
 535                  * This case can happen if the user changed the MTU
 536                  * of an interface after enabling IP on it.  Because
 537                  * most netifs don't keep track of routes pointing to
 538                  * them, there is no way for one to update all its
 539                  * routes when the MTU is changed.
 540                  */
 541                 if (ro != NULL &&
 542                     (ro->ro_rt->rt_flags & (RTF_UP | RTF_HOST)) &&
 543                     (ro->ro_rt->rt_rmx.rmx_mtu > ifp->if_mtu)) {
 544                         ro->ro_rt->rt_rmx.rmx_mtu = ifp->if_mtu;
 545                 }
 546                 ipstat.ips_cantfrag++;
 547                 goto bad;
 548         }
 549
 550         /*
 551          * Too large for interface; fragment if possible. If successful,
 552          * on return, m will point to a list of packets to be sent.
 553          */
 554         error = ip_fragment(ip, &m, ifp->if_mtu, ifp->if_hwassist, sw_csum);
 555         if (error)
 556                 goto bad;
 557         for (; m; m = m0) {
 558                 m0 = m->m_nextpkt;
 559                 m->m_nextpkt = 0;
 560 #ifdef IPSEC
 561                 /* clean ipsec history once it goes out of the node */
 562                 ipsec_delaux(m);
 563 #endif
 564                 if (error == 0) {
 565                         /* Record statistics for this interface address. */
 566                         if (ia != NULL) {
 567                                 ia->ia_ifa.if_opackets++;
 568                                 ia->ia_ifa.if_obytes += m->m_pkthdr.len;
 569                         }
 570                         /*
 571                          * Reset layer specific mbuf flags
 572                          * to avoid confusing upper layers.
 573                          */
 574                         m->m_flags &= ~(M_PROTOFLAGS);
 575
 576                         error = (*ifp->if_output)(ifp, m,
 577                             (struct sockaddr *)dst, ro->ro_rt);
 578                 } else
 579                         m_freem(m);
 580         }
 581
 582         if (error == 0)
 583                 ipstat.ips_fragmented++;
 584
 585 done:
 586         if (ro == &iproute && ro->ro_rt) {
 587                 RTFREE(ro->ro_rt);
 588         }
 589         return (error);
 590 bad:
 591         m_freem(m);
 592         goto done;
 593 }
 594
 595 /*
 596  * Create a chain of fragments which fit the given mtu. m_frag points to the
 597  * mbuf to be fragmented; on return it points to the chain with the fragments.
 598  * Return 0 if no error. If error, m_frag may contain a partially built
 599  * chain of fragments that should be freed by the caller.
 600  *
 601  * if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist)
 602  * sw_csum contains the delayed checksums flags (e.g., CSUM_DELAY_IP).
 603  */
 604 int
 605 ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu,
 606             u_long if_hwassist_flags, int sw_csum)
 607 {
 608         int error = 0;
 609         int hlen = ip->ip_hl << 2;
 610         int len = (mtu - hlen) & ~7;    /* size of payload in each fragment */
 611         int off;
 612         struct mbuf *m0 = *m_frag;      /* the original packet          */
 613         int firstlen;
 614         struct mbuf **mnext;
 615         int nfrags;
 616
 617         if (ip->ip_off & IP_DF) {       /* Fragmentation not allowed */
 618                 ipstat.ips_cantfrag++;
 619                 return EMSGSIZE;
 620         }
 621
 622         /*
 623          * Must be able to put at least 8 bytes per fragment.
 624          */
 625         if (len < 8)
 626                 return EMSGSIZE;
 627
 628         /*
 629          * If the interface will not calculate checksums on
 630          * fragmented packets, then do it here.
 631          */
 632         if (m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA &&
 633             (if_hwassist_flags & CSUM_IP_FRAGS) == 0) {
 634                 in_delayed_cksum(m0);
 635                 m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
 636         }
 637
 638         if (len > PAGE_SIZE) {
 639                 /*
 640                  * Fragment large datagrams such that each segment
 641                  * contains a multiple of PAGE_SIZE amount of data,
 642                  * plus headers. This enables a receiver to perform
 643                  * page-flipping zero-copy optimizations.
 644                  *
 645                  * XXX When does this help given that sender and receiver
 646                  * could have different page sizes, and also mtu could
 647                  * be less than the receiver's page size ?
 648                  */
 649                 int newlen;
 650                 struct mbuf *m;
 651
 652                 for (m = m0, off = 0; m && (off+m->m_len) <= mtu; m = m->m_next)
 653                         off += m->m_len;
 654
 655                 /*
 656                  * firstlen (off - hlen) must be aligned on an
 657                  * 8-byte boundary
 658                  */
 659                 if (off < hlen)
 660                         goto smart_frag_failure;
 661                 off = ((off - hlen) & ~7) + hlen;
 662                 newlen = (~PAGE_MASK) & mtu;
 663                 if ((newlen + sizeof (struct ip)) > mtu) {
 664                         /* we failed, go back the default */
 665 smart_frag_failure:
 666                         newlen = len;
 667                         off = hlen + len;
 668                 }
 669                 len = newlen;
 670
 671         } else {
 672                 off = hlen + len;
 673         }
 674
 675         firstlen = off - hlen;
 676         mnext = &m0->m_nextpkt;         /* pointer to next packet */
 677
 678         /*
 679          * Loop through length of segment after first fragment,
 680          * make new header and copy data of each part and link onto chain.
 681          * Here, m0 is the original packet, m is the fragment being created.
 682          * The fragments are linked off the m_nextpkt of the original
 683          * packet, which after processing serves as the first fragment.
 684          */
 685         for (nfrags = 1; off < ip->ip_len; off += len, nfrags++) {
 686                 struct ip *mhip;        /* ip header on the fragment */
 687                 struct mbuf *m;
 688                 int mhlen = sizeof (struct ip);
 689
 690                 MGETHDR(m, M_DONTWAIT, MT_DATA);
 691                 if (m == NULL) {
 692                         error = ENOBUFS;
 693                         ipstat.ips_odropped++;
 694                         goto done;
 695                 }
 696                 m->m_flags |= (m0->m_flags & M_MCAST) | M_FRAG;
 697                 /*
 698                  * In the first mbuf, leave room for the link header, then
 699                  * copy the original IP header including options. The payload
 700                  * goes into an additional mbuf chain returned by m_copy().
 701                  */
 702                 m->m_data += max_linkhdr;
 703                 mhip = mtod(m, struct ip *);
 704                 *mhip = *ip;
 705                 if (hlen > sizeof (struct ip)) {
 706                         mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
 707                         mhip->ip_v = IPVERSION;
 708                         mhip->ip_hl = mhlen >> 2;
 709                 }
 710                 m->m_len = mhlen;
 711                 /* XXX do we need to add ip->ip_off below ? */
 712                 mhip->ip_off = ((off - hlen) >> 3) + ip->ip_off;
 713                 if (off + len >= ip->ip_len) {  /* last fragment */
 714                         len = ip->ip_len - off;
 715                         m->m_flags |= M_LASTFRAG;
 716                 } else
 717                         mhip->ip_off |= IP_MF;
 718                 mhip->ip_len = htons((u_short)(len + mhlen));
 719                 m->m_next = m_copy(m0, off, len);
 720                 if (m->m_next == NULL) {        /* copy failed */
 721                         m_free(m);
 722                         error = ENOBUFS;        /* ??? */
 723                         ipstat.ips_odropped++;
 724                         goto done;
 725                 }
 726                 m->m_pkthdr.len = mhlen + len;
 727                 m->m_pkthdr.rcvif = NULL;
 728 #ifdef MAC
 729                 mac_create_fragment(m0, m);
 730 #endif
 731                 m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags;
 732                 mhip->ip_off = htons(mhip->ip_off);
 733                 mhip->ip_sum = 0;
 734                 if (sw_csum & CSUM_DELAY_IP)
 735                         mhip->ip_sum = in_cksum(m, mhlen);
 736                 *mnext = m;
 737                 mnext = &m->m_nextpkt;
 738         }
 739         ipstat.ips_ofragments += nfrags;
 740
 741         /* set first marker for fragment chain */
 742         m0->m_flags |= M_FIRSTFRAG | M_FRAG;
 743         m0->m_pkthdr.csum_data = nfrags;
 744
 745         /*
 746          * Update first fragment by trimming what's been copied out
 747          * and updating header.
 748          */
 749         m_adj(m0, hlen + firstlen - ip->ip_len);
 750         m0->m_pkthdr.len = hlen + firstlen;
 751         ip->ip_len = htons((u_short)m0->m_pkthdr.len);
 752         ip->ip_off |= IP_MF;
 753         ip->ip_off = htons(ip->ip_off);
 754         ip->ip_sum = 0;
 755         if (sw_csum & CSUM_DELAY_IP)
 756                 ip->ip_sum = in_cksum(m0, hlen);
 757
 758 done:
 759         *m_frag = m0;
 760         return error;
 761 }
 762
 763 void
 764 in_delayed_cksum(struct mbuf *m)
 765 {
 766         struct ip *ip;
 767         u_short csum, offset;
 768
 769         ip = mtod(m, struct ip *);
 770         offset = ip->ip_hl << 2 ;
 771         csum = in_cksum_skip(m, ip->ip_len, offset);
 772         if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0)
 773                 csum = 0xffff;
 774         offset += m->m_pkthdr.csum_data;        /* checksum offset */
 775
 776         if (offset + sizeof(u_short) > m->m_len) {
 777                 printf("delayed m_pullup, m->len: %d  off: %d  p: %d\n",
 778                     m->m_len, offset, ip->ip_p);
 779                 /*
 780                  * XXX
 781                  * this shouldn't happen, but if it does, the
 782                  * correct behavior may be to insert the checksum
 783                  * in the appropriate next mbuf in the chain.
 784                  */
 785                 return;
 786         }
 787         *(u_short *)(m->m_data + offset) = csum;
 788 }
 789
 790 /*
 791  * IP socket option processing.
 792  */
 793 int
 794 ip_ctloutput(so, sopt)
 795         struct socket *so;
 796         struct sockopt *sopt;
 797 {
 798         struct  inpcb *inp = sotoinpcb(so);
 799         int     error, optval;
 800
 801         error = optval = 0;
 802         if (sopt->sopt_level != IPPROTO_IP) {
 803                 return (EINVAL);
 804         }
 805
 806         switch (sopt->sopt_dir) {
 807         case SOPT_SET:
 808                 switch (sopt->sopt_name) {
 809                 case IP_OPTIONS:
 810 #ifdef notyet
 811                 case IP_RETOPTS:
 812 #endif
 813                 {
 814                         struct mbuf *m;
 815                         if (sopt->sopt_valsize > MLEN) {
 816                                 error = EMSGSIZE;
 817                                 break;
 818                         }
 819                         MGET(m, sopt->sopt_td ? M_TRYWAIT : M_DONTWAIT, MT_DATA);
 820                         if (m == NULL) {
 821                                 error = ENOBUFS;
 822                                 break;
 823                         }
 824                         m->m_len = sopt->sopt_valsize;
 825                         error = sooptcopyin(sopt, mtod(m, char *), m->m_len,
 826                                             m->m_len);
 827                         if (error) {
 828                                 m_free(m);
 829                                 break;
 830                         }
 831                         INP_LOCK(inp);
 832                         error = ip_pcbopts(inp, sopt->sopt_name, m);
 833                         INP_UNLOCK(inp);
 834                         return (error);
 835                 }
 836
 837                 case IP_TOS:
 838                 case IP_TTL:
 839                 case IP_MINTTL:
 840                 case IP_RECVOPTS:
 841                 case IP_RECVRETOPTS:
 842                 case IP_RECVDSTADDR:
 843                 case IP_RECVTTL:
 844                 case IP_RECVIF:
 845                 case IP_FAITH:
 846                 case IP_ONESBCAST:
 847                 case IP_DONTFRAG:
 848                         error = sooptcopyin(sopt, &optval, sizeof optval,
 849                                             sizeof optval);
 850                         if (error)
 851                                 break;
 852
 853                         switch (sopt->sopt_name) {
 854                         case IP_TOS:
 855                                 inp->inp_ip_tos = optval;
 856                                 break;
 857
 858                         case IP_TTL:
 859                                 inp->inp_ip_ttl = optval;
 860                                 break;
 861
 862                         case IP_MINTTL:
 863                                 if (optval > 0 && optval <= MAXTTL)
 864                                         inp->inp_ip_minttl = optval;
 865                                 else
 866                                         error = EINVAL;
 867                                 break;
 868
 869 #define OPTSET(bit) do {                                                \
 870         INP_LOCK(inp);                                                  \
 871         if (optval)                                                     \
 872                 inp->inp_flags |= bit;                                  \
 873         else                                                            \
 874                 inp->inp_flags &= ~bit;                                 \
 875         INP_UNLOCK(inp);                                                \
 876 } while (0)
 877
 878                         case IP_RECVOPTS:
 879                                 OPTSET(INP_RECVOPTS);
 880                                 break;
 881
 882                         case IP_RECVRETOPTS:
 883                                 OPTSET(INP_RECVRETOPTS);
 884                                 break;
 885
 886                         case IP_RECVDSTADDR:
 887                                 OPTSET(INP_RECVDSTADDR);
 888                                 break;
 889
 890                         case IP_RECVTTL:
 891                                 OPTSET(INP_RECVTTL);
 892                                 break;
 893
 894                         case IP_RECVIF:
 895                                 OPTSET(INP_RECVIF);
 896                                 break;
 897
 898                         case IP_FAITH:
 899                                 OPTSET(INP_FAITH);
 900                                 break;
 901
 902                         case IP_ONESBCAST:
 903                                 OPTSET(INP_ONESBCAST);
 904                                 break;
 905                         case IP_DONTFRAG:
 906                                 OPTSET(INP_DONTFRAG);
 907                                 break;
 908                         }
 909                         break;
 910 #undef OPTSET
 911
 912                 case IP_MULTICAST_IF:
 913                 case IP_MULTICAST_VIF:
 914                 case IP_MULTICAST_TTL:
 915                 case IP_MULTICAST_LOOP:
 916                 case IP_ADD_MEMBERSHIP:
 917                 case IP_DROP_MEMBERSHIP:
 918                         error = ip_setmoptions(inp, sopt);
 919                         break;
 920
 921                 case IP_PORTRANGE:
 922                         error = sooptcopyin(sopt, &optval, sizeof optval,
 923                                             sizeof optval);
 924                         if (error)
 925                                 break;
 926
 927                         INP_LOCK(inp);
 928                         switch (optval) {
 929                         case IP_PORTRANGE_DEFAULT:
 930                                 inp->inp_flags &= ~(INP_LOWPORT);
 931                                 inp->inp_flags &= ~(INP_HIGHPORT);
 932                                 break;
 933
 934                         case IP_PORTRANGE_HIGH:
 935                                 inp->inp_flags &= ~(INP_LOWPORT);
 936                                 inp->inp_flags |= INP_HIGHPORT;
 937                                 break;
 938
 939                         case IP_PORTRANGE_LOW:
 940                                 inp->inp_flags &= ~(INP_HIGHPORT);
 941                                 inp->inp_flags |= INP_LOWPORT;
 942                                 break;
 943
 944                         default:
 945                                 error = EINVAL;
 946                                 break;
 947                         }
 948                         INP_UNLOCK(inp);
 949                         break;
 950
 951 #if defined(IPSEC) || defined(FAST_IPSEC)
 952                 case IP_IPSEC_POLICY:
 953                 {
 954                         caddr_t req;
 955                         size_t len = 0;
 956                         int priv;
 957                         struct mbuf *m;
 958                         int optname;
 959
 960                         if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */
 961                                 break;
 962                         if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */
 963                                 break;
 964                         priv = (sopt->sopt_td != NULL &&
 965                                 suser(sopt->sopt_td) != 0) ? 0 : 1;
 966                         req = mtod(m, caddr_t);
 967                         len = m->m_len;
 968                         optname = sopt->sopt_name;
 969                         error = ipsec4_set_policy(inp, optname, req, len, priv);
 970                         m_freem(m);
 971                         break;
 972                 }
 973 #endif /*IPSEC*/
 974
 975                 default:
 976                         error = ENOPROTOOPT;
 977                         break;
 978                 }
 979                 break;
 980
 981         case SOPT_GET:
 982                 switch (sopt->sopt_name) {
 983                 case IP_OPTIONS:
 984                 case IP_RETOPTS:
 985                         if (inp->inp_options)
 986                                 error = sooptcopyout(sopt,
 987                                                      mtod(inp->inp_options,
 988                                                           char *),
 989                                                      inp->inp_options->m_len);
 990                         else
 991                                 sopt->sopt_valsize = 0;
 992                         break;
 993
 994                 case IP_TOS:
 995                 case IP_TTL:
 996                 case IP_MINTTL:
 997                 case IP_RECVOPTS:
 998                 case IP_RECVRETOPTS:
 999                 case IP_RECVDSTADDR:
1000                 case IP_RECVTTL:
1001                 case IP_RECVIF:
1002                 case IP_PORTRANGE:
1003                 case IP_FAITH:
1004                 case IP_ONESBCAST:
1005                 case IP_DONTFRAG:
1006                         switch (sopt->sopt_name) {
1007
1008                         case IP_TOS:
1009                                 optval = inp->inp_ip_tos;
1010                                 break;
1011
1012                         case IP_TTL:
1013                                 optval = inp->inp_ip_ttl;
1014                                 break;
1015
1016                         case IP_MINTTL:
1017                                 optval = inp->inp_ip_minttl;
1018                                 break;
1019
1020 #define OPTBIT(bit)     (inp->inp_flags & bit ? 1 : 0)
1021
1022                         case IP_RECVOPTS:
1023                                 optval = OPTBIT(INP_RECVOPTS);
1024                                 break;
1025
1026                         case IP_RECVRETOPTS:
1027                                 optval = OPTBIT(INP_RECVRETOPTS);
1028                                 break;
1029
1030                         case IP_RECVDSTADDR:
1031                                 optval = OPTBIT(INP_RECVDSTADDR);
1032                                 break;
1033
1034                         case IP_RECVTTL:
1035                                 optval = OPTBIT(INP_RECVTTL);
1036                                 break;
1037
1038                         case IP_RECVIF:
1039                                 optval = OPTBIT(INP_RECVIF);
1040                                 break;
1041
1042                         case IP_PORTRANGE:
1043                                 if (inp->inp_flags & INP_HIGHPORT)
1044                                         optval = IP_PORTRANGE_HIGH;
1045                                 else if (inp->inp_flags & INP_LOWPORT)
1046                                         optval = IP_PORTRANGE_LOW;
1047                                 else
1048                                         optval = 0;
1049                                 break;
1050
1051                         case IP_FAITH:
1052                                 optval = OPTBIT(INP_FAITH);
1053                                 break;
1054
1055                         case IP_ONESBCAST:
1056                                 optval = OPTBIT(INP_ONESBCAST);
1057                                 break;
1058                         case IP_DONTFRAG:
1059                                 optval = OPTBIT(INP_DONTFRAG);
1060                                 break;
1061                         }
1062                         error = sooptcopyout(sopt, &optval, sizeof optval);
1063                         break;
1064
1065                 case IP_MULTICAST_IF:
1066                 case IP_MULTICAST_VIF:
1067                 case IP_MULTICAST_TTL:
1068                 case IP_MULTICAST_LOOP:
1069                 case IP_ADD_MEMBERSHIP:
1070                 case IP_DROP_MEMBERSHIP:
1071                         error = ip_getmoptions(inp, sopt);
1072                         break;
1073
1074 #if defined(IPSEC) || defined(FAST_IPSEC)
1075                 case IP_IPSEC_POLICY:
1076                 {
1077                         struct mbuf *m = NULL;
1078                         caddr_t req = NULL;
1079                         size_t len = 0;
1080
1081                         if (m != 0) {
1082                                 req = mtod(m, caddr_t);
1083                                 len = m->m_len;
1084                         }
1085                         error = ipsec4_get_policy(sotoinpcb(so), req, len, &m);
1086                         if (error == 0)
1087                                 error = soopt_mcopyout(sopt, m); /* XXX */
1088                         if (error == 0)
1089                                 m_freem(m);
1090                         break;
1091                 }
1092 #endif /*IPSEC*/
1093
1094                 default:
1095                         error = ENOPROTOOPT;
1096                         break;
1097                 }
1098                 break;
1099         }
1100         return (error);
1101 }
1102
1103 /*
1104  * XXX
1105  * The whole multicast option thing needs to be re-thought.
1106  * Several of these options are equally applicable to non-multicast
1107  * transmission, and one (IP_MULTICAST_TTL) totally duplicates a
1108  * standard option (IP_TTL).
1109  */
1110
1111 /*
1112  * following RFC1724 section 3.3, 0.0.0.0/8 is interpreted as interface index.
1113  */
1114 static struct ifnet *
1115 ip_multicast_if(a, ifindexp)
1116         struct in_addr *a;
1117         int *ifindexp;
1118 {
1119         int ifindex;
1120         struct ifnet *ifp;
1121
1122         if (ifindexp)
1123                 *ifindexp = 0;
1124         if (ntohl(a->s_addr) >> 24 == 0) {
1125                 ifindex = ntohl(a->s_addr) & 0xffffff;
1126                 if (ifindex < 0 || if_index < ifindex)
1127                         return NULL;
1128                 ifp = ifnet_byindex(ifindex);
1129                 if (ifindexp)
1130                         *ifindexp = ifindex;
1131         } else {
1132                 INADDR_TO_IFP(*a, ifp);
1133         }
1134         return ifp;
1135 }
1136
1137 /*
1138  * Given an inpcb, return its multicast options structure pointer.  Accepts
1139  * an unlocked inpcb pointer, but will return it locked.  May sleep.
1140  */
1141 static struct ip_moptions *
1142 ip_findmoptions(struct inpcb *inp)
1143 {
1144         struct ip_moptions *imo;
1145         struct in_multi **immp;
1146
1147         INP_LOCK(inp);
1148         if (inp->inp_moptions != NULL)
1149                 return (inp->inp_moptions);
1150
1151         INP_UNLOCK(inp);
1152
1153         imo = (struct ip_moptions*)malloc(sizeof(*imo), M_IPMOPTS, M_WAITOK);
1154         immp = (struct in_multi **)malloc((sizeof(*immp) * IP_MIN_MEMBERSHIPS),
1155                                           M_IPMOPTS, M_WAITOK);
1156
1157         imo->imo_multicast_ifp = NULL;
1158         imo->imo_multicast_addr.s_addr = INADDR_ANY;
1159         imo->imo_multicast_vif = -1;
1160         imo->imo_multicast_ttl = IP_DEFAULT_MULTICAST_TTL;
1161         imo->imo_multicast_loop = IP_DEFAULT_MULTICAST_LOOP;
1162         imo->imo_num_memberships = 0;
1163         imo->imo_max_memberships = IP_MIN_MEMBERSHIPS;
1164         imo->imo_membership = immp;
1165
1166         INP_LOCK(inp);
1167         if (inp->inp_moptions != NULL) {
1168                 free(immp, M_IPMOPTS);
1169                 free(imo, M_IPMOPTS);
1170                 return (inp->inp_moptions);
1171         }
1172         inp->inp_moptions = imo;
1173         return (imo);
1174 }
1175
1176 /*
1177  * Set the IP multicast options in response to user setsockopt().
1178  */
1179 static int
1180 ip_setmoptions(struct inpcb *inp, struct sockopt *sopt)
1181 {
1182         int error = 0;
1183         int i;
1184         struct in_addr addr;
1185         struct ip_mreq mreq;
1186         struct ifnet *ifp;
1187         struct ip_moptions *imo;
1188         struct route ro;
1189         struct sockaddr_in *dst;
1190         int ifindex;
1191         int s;
1192
1193         switch (sopt->sopt_name) {
1194         /* store an index number for the vif you wanna use in the send */
1195         case IP_MULTICAST_VIF:
1196                 if (legal_vif_num == 0) {
1197                         error = EOPNOTSUPP;
1198                         break;
1199                 }
1200                 error = sooptcopyin(sopt, &i, sizeof i, sizeof i);
1201                 if (error)
1202                         break;
1203                 if (!legal_vif_num(i) && (i != -1)) {
1204                         error = EINVAL;
1205                         break;
1206                 }
1207                 imo = ip_findmoptions(inp);
1208                 imo->imo_multicast_vif = i;
1209                 INP_UNLOCK(inp);
1210                 break;
1211
1212         case IP_MULTICAST_IF:
1213                 /*
1214                  * Select the interface for outgoing multicast packets.
1215                  */
1216                 error = sooptcopyin(sopt, &addr, sizeof addr, sizeof addr);
1217                 if (error)
1218                         break;
1219                 /*
1220                  * INADDR_ANY is used to remove a previous selection.
1221                  * When no interface is selected, a default one is
1222                  * chosen every time a multicast packet is sent.
1223                  */
1224                 imo = ip_findmoptions(inp);
1225                 if (addr.s_addr == INADDR_ANY) {
1226                         imo->imo_multicast_ifp = NULL;
1227                         INP_UNLOCK(inp);
1228                         break;
1229                 }
1230                 /*
1231                  * The selected interface is identified by its local
1232                  * IP address.  Find the interface and confirm that
1233                  * it supports multicasting.
1234                  */
1235                 s = splimp();
1236                 ifp = ip_multicast_if(&addr, &ifindex);
1237                 if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) {
1238                         INP_UNLOCK(inp);
1239                         splx(s);
1240                         error = EADDRNOTAVAIL;
1241                         break;
1242                 }
1243                 imo->imo_multicast_ifp = ifp;
1244                 if (ifindex)
1245                         imo->imo_multicast_addr = addr;
1246                 else
1247                         imo->imo_multicast_addr.s_addr = INADDR_ANY;
1248                 INP_UNLOCK(inp);
1249                 splx(s);
1250                 break;
1251
1252         case IP_MULTICAST_TTL:
1253                 /*
1254                  * Set the IP time-to-live for outgoing multicast packets.
1255                  * The original multicast API required a char argument,
1256                  * which is inconsistent with the rest of the socket API.
1257                  * We allow either a char or an int.
1258                  */
1259                 if (sopt->sopt_valsize == 1) {
1260                         u_char ttl;
1261                         error = sooptcopyin(sopt, &ttl, 1, 1);
1262                         if (error)
1263                                 break;
1264                         imo = ip_findmoptions(inp);
1265                         imo->imo_multicast_ttl = ttl;
1266                         INP_UNLOCK(inp);
1267                 } else {
1268                         u_int ttl;
1269                         error = sooptcopyin(sopt, &ttl, sizeof ttl,
1270                                             sizeof ttl);
1271                         if (error)
1272                                 break;
1273                         if (ttl > 255)
1274                                 error = EINVAL;
1275                         else {
1276                                 imo = ip_findmoptions(inp);
1277                                 imo->imo_multicast_ttl = ttl;
1278                                 INP_UNLOCK(inp);
1279                         }
1280                 }
1281                 break;
1282
1283         case IP_MULTICAST_LOOP:
1284                 /*
1285                  * Set the loopback flag for outgoing multicast packets.
1286                  * Must be zero or one.  The original multicast API required a
1287                  * char argument, which is inconsistent with the rest
1288                  * of the socket API.  We allow either a char or an int.
1289                  */
1290                 if (sopt->sopt_valsize == 1) {
1291                         u_char loop;
1292                         error = sooptcopyin(sopt, &loop, 1, 1);
1293                         if (error)
1294                                 break;
1295                         imo = ip_findmoptions(inp);
1296                         imo->imo_multicast_loop = !!loop;
1297                         INP_UNLOCK(inp);
1298                 } else {
1299                         u_int loop;
1300                         error = sooptcopyin(sopt, &loop, sizeof loop,
1301                                             sizeof loop);
1302                         if (error)
1303                                 break;
1304                         imo = ip_findmoptions(inp);
1305                         imo->imo_multicast_loop = !!loop;
1306                         INP_UNLOCK(inp);
1307                 }
1308                 break;
1309
1310         case IP_ADD_MEMBERSHIP:
1311                 /*
1312                  * Add a multicast group membership.
1313                  * Group must be a valid IP multicast address.
1314                  */
1315                 error = sooptcopyin(sopt, &mreq, sizeof mreq, sizeof mreq);
1316                 if (error)
1317                         break;
1318
1319                 if (!IN_MULTICAST(ntohl(mreq.imr_multiaddr.s_addr))) {
1320                         error = EINVAL;
1321                         break;
1322                 }
1323                 s = splimp();
1324                 /*
1325                  * If no interface address was provided, use the interface of
1326                  * the route to the given multicast address.
1327                  */
1328                 if (mreq.imr_interface.s_addr == INADDR_ANY) {
1329                         bzero((caddr_t)&ro, sizeof(ro));
1330                         dst = (struct sockaddr_in *)&ro.ro_dst;
1331                         dst->sin_len = sizeof(*dst);
1332                         dst->sin_family = AF_INET;
1333                         dst->sin_addr = mreq.imr_multiaddr;
1334                         rtalloc_ign(&ro, RTF_CLONING);
1335                         if (ro.ro_rt == NULL) {
1336                                 error = EADDRNOTAVAIL;
1337                                 splx(s);
1338                                 break;
1339                         }
1340                         ifp = ro.ro_rt->rt_ifp;
1341                         RTFREE(ro.ro_rt);
1342                 }
1343                 else {
1344                         ifp = ip_multicast_if(&mreq.imr_interface, NULL);
1345                 }
1346
1347                 /*
1348                  * See if we found an interface, and confirm that it
1349                  * supports multicast.
1350                  */
1351                 if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) {
1352                         error = EADDRNOTAVAIL;
1353                         splx(s);
1354                         break;
1355                 }
1356                 /*
1357                  * See if the membership already exists or if all the
1358                  * membership slots are full.
1359                  */
1360                 imo = ip_findmoptions(inp);
1361                 for (i = 0; i < imo->imo_num_memberships; ++i) {
1362                         if (imo->imo_membership[i]->inm_ifp == ifp &&
1363                             imo->imo_membership[i]->inm_addr.s_addr
1364                                                 == mreq.imr_multiaddr.s_addr)
1365                                 break;
1366                 }
1367                 if (i < imo->imo_num_memberships) {
1368                         INP_UNLOCK(inp);
1369                         error = EADDRINUSE;
1370                         splx(s);
1371                         break;
1372                 }
1373                 if (imo->imo_num_memberships == imo->imo_max_memberships) {
1374                     struct in_multi **nmships, **omships;
1375                     size_t newmax;
1376                     /*
1377                      * Resize the vector to next power-of-two minus 1. If the
1378                      * size would exceed the maximum then we know we've really
1379                      * run out of entries. Otherwise, we realloc() the vector
1380                      * with the INP lock held to avoid introducing a race.
1381                      */
1382                     nmships = NULL;
1383                     omships = imo->imo_membership;
1384                     newmax = ((imo->imo_max_memberships + 1) * 2) - 1;
1385                     if (newmax <= IP_MAX_MEMBERSHIPS) {
1386                         nmships = (struct in_multi **)realloc(omships,
1387 sizeof(*nmships) * newmax, M_IPMOPTS, M_NOWAIT);
1388                         if (nmships != NULL) {
1389                             imo->imo_membership = nmships;
1390                             imo->imo_max_memberships = newmax;
1391                         }
1392                     }
1393                     if (nmships == NULL) {
1394                         INP_UNLOCK(inp);
1395                         error = ETOOMANYREFS;
1396                         splx(s);
1397                         break;
1398                     }
1399                 }
1400                 /*
1401                  * Everything looks good; add a new record to the multicast
1402                  * address list for the given interface.
1403                  */
1404                 if ((imo->imo_membership[i] =
1405                     in_addmulti(&mreq.imr_multiaddr, ifp)) == NULL) {
1406                         INP_UNLOCK(inp);
1407                         error = ENOBUFS;
1408                         splx(s);
1409                         break;
1410                 }
1411                 ++imo->imo_num_memberships;
1412                 INP_UNLOCK(inp);
1413                 splx(s);
1414                 break;
1415
1416         case IP_DROP_MEMBERSHIP:
1417                 /*
1418                  * Drop a multicast group membership.
1419                  * Group must be a valid IP multicast address.
1420                  */
1421                 error = sooptcopyin(sopt, &mreq, sizeof mreq, sizeof mreq);
1422                 if (error)
1423                         break;
1424
1425                 if (!IN_MULTICAST(ntohl(mreq.imr_multiaddr.s_addr))) {
1426                         error = EINVAL;
1427                         break;
1428                 }
1429
1430                 s = splimp();
1431                 /*
1432                  * If an interface address was specified, get a pointer
1433                  * to its ifnet structure.
1434                  */
1435                 if (mreq.imr_interface.s_addr == INADDR_ANY)
1436                         ifp = NULL;
1437                 else {
1438                         ifp = ip_multicast_if(&mreq.imr_interface, NULL);
1439                         if (ifp == NULL) {
1440                                 error = EADDRNOTAVAIL;
1441                                 splx(s);
1442                                 break;
1443                         }
1444                 }
1445                 /*
1446                  * Find the membership in the membership array.
1447                  */
1448                 imo = ip_findmoptions(inp);
1449                 for (i = 0; i < imo->imo_num_memberships; ++i) {
1450                         if ((ifp == NULL ||
1451                              imo->imo_membership[i]->inm_ifp == ifp) &&
1452                              imo->imo_membership[i]->inm_addr.s_addr ==
1453                              mreq.imr_multiaddr.s_addr)
1454                                 break;
1455                 }
1456                 if (i == imo->imo_num_memberships) {
1457                         INP_UNLOCK(inp);
1458                         error = EADDRNOTAVAIL;
1459                         splx(s);
1460                         break;
1461                 }
1462                 /*
1463                  * Give up the multicast address record to which the
1464                  * membership points.
1465                  */
1466                 in_delmulti(imo->imo_membership[i]);
1467                 /*
1468                  * Remove the gap in the membership array.
1469                  */
1470                 for (++i; i < imo->imo_num_memberships; ++i)
1471                         imo->imo_membership[i-1] = imo->imo_membership[i];
1472                 --imo->imo_num_memberships;
1473                 INP_UNLOCK(inp);
1474                 splx(s);
1475                 break;
1476
1477         default:
1478                 error = EOPNOTSUPP;
1479                 break;
1480         }
1481
1482         return (error);
1483 }
1484
1485 /*
1486  * Return the IP multicast options in response to user getsockopt().
1487  */
1488 static int
1489 ip_getmoptions(struct inpcb *inp, struct sockopt *sopt)
1490 {
1491         struct ip_moptions *imo;
1492         struct in_addr addr;
1493         struct in_ifaddr *ia;
1494         int error, optval;
1495         u_char coptval;
1496
1497         INP_LOCK(inp);
1498         imo = inp->inp_moptions;
1499
1500         error = 0;
1501         switch (sopt->sopt_name) {
1502         case IP_MULTICAST_VIF:
1503                 if (imo != NULL)
1504                         optval = imo->imo_multicast_vif;
1505                 else
1506                         optval = -1;
1507                 INP_UNLOCK(inp);
1508                 error = sooptcopyout(sopt, &optval, sizeof optval);
1509                 break;
1510
1511         case IP_MULTICAST_IF:
1512                 if (imo == NULL || imo->imo_multicast_ifp == NULL)
1513                         addr.s_addr = INADDR_ANY;
1514                 else if (imo->imo_multicast_addr.s_addr) {
1515                         /* return the value user has set */
1516                         addr = imo->imo_multicast_addr;
1517                 } else {
1518                         IFP_TO_IA(imo->imo_multicast_ifp, ia);
1519                         addr.s_addr = (ia == NULL) ? INADDR_ANY
1520                                 : IA_SIN(ia)->sin_addr.s_addr;
1521                 }
1522                 INP_UNLOCK(inp);
1523                 error = sooptcopyout(sopt, &addr, sizeof addr);
1524                 break;
1525
1526         case IP_MULTICAST_TTL:
1527                 if (imo == 0)
1528                         optval = coptval = IP_DEFAULT_MULTICAST_TTL;
1529                 else
1530                         optval = coptval = imo->imo_multicast_ttl;
1531                 INP_UNLOCK(inp);
1532                 if (sopt->sopt_valsize == 1)
1533                         error = sooptcopyout(sopt, &coptval, 1);
1534                 else
1535                         error = sooptcopyout(sopt, &optval, sizeof optval);
1536                 break;
1537
1538         case IP_MULTICAST_LOOP:
1539                 if (imo == 0)
1540                         optval = coptval = IP_DEFAULT_MULTICAST_LOOP;
1541                 else
1542                         optval = coptval = imo->imo_multicast_loop;
1543                 INP_UNLOCK(inp);
1544                 if (sopt->sopt_valsize == 1)
1545                         error = sooptcopyout(sopt, &coptval, 1);
1546                 else
1547                         error = sooptcopyout(sopt, &optval, sizeof optval);
1548                 break;
1549
1550         default:
1551                 INP_UNLOCK(inp);
1552                 error = ENOPROTOOPT;
1553                 break;
1554         }
1555         INP_UNLOCK_ASSERT(inp);
1556
1557         return (error);
1558 }
1559
1560 /*
1561  * Discard the IP multicast options.
1562  */
1563 void
1564 ip_freemoptions(imo)
1565         register struct ip_moptions *imo;
1566 {
1567         register int i;
1568
1569         if (imo != NULL) {
1570                 for (i = 0; i < imo->imo_num_memberships; ++i)
1571                         in_delmulti(imo->imo_membership[i]);
1572                 free(imo->imo_membership, M_IPMOPTS);
1573                 free(imo, M_IPMOPTS);
1574         }
1575 }
1576
1577 /*
1578  * Routine called from ip_output() to loop back a copy of an IP multicast
1579  * packet to the input queue of a specified interface.  Note that this
1580  * calls the output routine of the loopback "driver", but with an interface
1581  * pointer that might NOT be a loopback interface -- evil, but easier than
1582  * replicating that code here.
1583  */
1584 static void
1585 ip_mloopback(ifp, m, dst, hlen)
1586         struct ifnet *ifp;
1587         register struct mbuf *m;
1588         register struct sockaddr_in *dst;
1589         int hlen;
1590 {
1591         register struct ip *ip;
1592         struct mbuf *copym;
1593
1594         copym = m_copy(m, 0, M_COPYALL);
1595         if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen))
1596                 copym = m_pullup(copym, hlen);
1597         if (copym != NULL) {
1598                 /* If needed, compute the checksum and mark it as valid. */
1599                 if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
1600                         in_delayed_cksum(copym);
1601                         copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
1602                         copym->m_pkthdr.csum_flags |=
1603                             CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
1604                         copym->m_pkthdr.csum_data = 0xffff;
1605                 }
1606                 /*
1607                  * We don't bother to fragment if the IP length is greater
1608                  * than the interface's MTU.  Can this possibly matter?
1609                  */
1610                 ip = mtod(copym, struct ip *);
1611                 ip->ip_len = htons(ip->ip_len);
1612                 ip->ip_off = htons(ip->ip_off);
1613                 ip->ip_sum = 0;
1614                 ip->ip_sum = in_cksum(copym, hlen);
1615                 /*
1616                  * NB:
1617                  * It's not clear whether there are any lingering
1618                  * reentrancy problems in other areas which might
1619                  * be exposed by using ip_input directly (in
1620                  * particular, everything which modifies the packet
1621                  * in-place).  Yet another option is using the
1622                  * protosw directly to deliver the looped back
1623                  * packet.  For the moment, we'll err on the side
1624                  * of safety by using if_simloop().
1625                  */
1626 #if 1 /* XXX */
1627                 if (dst->sin_family != AF_INET) {
1628                         printf("ip_mloopback: bad address family %d\n",
1629                                                 dst->sin_family);
1630                         dst->sin_family = AF_INET;
1631                 }
1632 #endif
1633
1634 #ifdef notdef
1635                 copym->m_pkthdr.rcvif = ifp;
1636                 ip_input(copym);
1637 #else
1638                 if_simloop(ifp, copym, dst->sin_family, 0);
1639 #endif
1640         }
1641 }