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  * 3. 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: src/sys/netinet/ip_output.c,v 1.99.2.37 2003/04/15 06:44:45 silby Exp $
  31  * $DragonFly: src/sys/netinet/ip_output.c,v 1.26 2005/02/11 22:25:57 joerg Exp $
  32  */
  33
  34 #define _IP_VHL
  35
  36 #include "opt_ipfw.h"
  37 #include "opt_ipdn.h"
  38 #include "opt_ipdivert.h"
  39 #include "opt_ipfilter.h"
  40 #include "opt_ipsec.h"
  41 #include "opt_random_ip_id.h"
  42 #include "opt_mbuf_stress_test.h"
  43
  44 #include <sys/param.h>
  45 #include <sys/systm.h>
  46 #include <sys/kernel.h>
  47 #include <sys/malloc.h>
  48 #include <sys/mbuf.h>
  49 #include <sys/protosw.h>
  50 #include <sys/socket.h>
  51 #include <sys/socketvar.h>
  52 #include <sys/proc.h>
  53 #include <sys/sysctl.h>
  54 #include <sys/in_cksum.h>
  55
  56 #include <net/if.h>
  57 #include <net/netisr.h>
  58 #include <net/pfil.h>
  59 #include <net/route.h>
  60
  61 #include <netinet/in.h>
  62 #include <netinet/in_systm.h>
  63 #include <netinet/ip.h>
  64 #include <netinet/in_pcb.h>
  65 #include <netinet/in_var.h>
  66 #include <netinet/ip_var.h>
  67
  68 static MALLOC_DEFINE(M_IPMOPTS, "ip_moptions", "internet multicast options");
  69
  70 #ifdef IPSEC
  71 #include <netinet6/ipsec.h>
  72 #include <netproto/key/key.h>
  73 #ifdef IPSEC_DEBUG
  74 #include <netproto/key/key_debug.h>
  75 #else
  76 #define KEYDEBUG(lev,arg)
  77 #endif
  78 #endif /*IPSEC*/
  79
  80 #ifdef FAST_IPSEC
  81 #include <netproto/ipsec/ipsec.h>
  82 #include <netproto/ipsec/xform.h>
  83 #include <netproto/ipsec/key.h>
  84 #endif /*FAST_IPSEC*/
  85
  86 #include <net/ipfw/ip_fw.h>
  87 #include <net/dummynet/ip_dummynet.h>
  88
  89 #define print_ip(x, a, y)        printf("%s %d.%d.%d.%d%s",\
  90                                 x, (ntohl(a.s_addr)>>24)&0xFF,\
  91                                   (ntohl(a.s_addr)>>16)&0xFF,\
  92                                   (ntohl(a.s_addr)>>8)&0xFF,\
  93                                   (ntohl(a.s_addr))&0xFF, y);
  94
  95 u_short ip_id;
  96
  97 #ifdef MBUF_STRESS_TEST
  98 int mbuf_frag_size = 0;
  99 SYSCTL_INT(_net_inet_ip, OID_AUTO, mbuf_frag_size, CTLFLAG_RW,
 100         &mbuf_frag_size, 0, "Fragment outgoing mbufs to this size");
 101 #endif
 102
 103 static struct mbuf *ip_insertoptions(struct mbuf *, struct mbuf *, int *);
 104 static struct ifnet *ip_multicast_if(struct in_addr *, int *);
 105 static void     ip_mloopback
 106         (struct ifnet *, struct mbuf *, struct sockaddr_in *, int);
 107 static int      ip_getmoptions
 108         (struct sockopt *, struct ip_moptions *);
 109 static int      ip_pcbopts(int, struct mbuf **, struct mbuf *);
 110 static int      ip_setmoptions
 111         (struct sockopt *, struct ip_moptions **);
 112
 113 int     ip_optcopy(struct ip *, struct ip *);
 114
 115
 116 extern  struct protosw inetsw[];
 117
 118 /*
 119  * IP output.  The packet in mbuf chain m contains a skeletal IP
 120  * header (with len, off, ttl, proto, tos, src, dst).
 121  * The mbuf chain containing the packet will be freed.
 122  * The mbuf opt, if present, will not be freed.
 123  */
 124 int
 125 ip_output(struct mbuf *m0, struct mbuf *opt, struct route *ro,
 126           int flags, struct ip_moptions *imo, struct inpcb *inp)
 127 {
 128         struct ip *ip;
 129         struct ifnet *ifp = NULL;       /* keep compiler happy */
 130         struct mbuf *m;
 131         int hlen = sizeof(struct ip);
 132         int len, off, error = 0;
 133         struct sockaddr_in *dst = NULL; /* keep compiler happy */
 134         struct in_ifaddr *ia = NULL;
 135         int isbroadcast, sw_csum;
 136         struct in_addr pkt_dst;
 137         struct route iproute;
 138 #ifdef IPSEC
 139         struct secpolicy *sp = NULL;
 140         struct socket *so = inp ? inp->inp_socket : NULL;
 141 #endif
 142 #ifdef FAST_IPSEC
 143         struct m_tag *mtag;
 144         struct secpolicy *sp = NULL;
 145         struct tdb_ident *tdbi;
 146         int s;
 147 #endif /* FAST_IPSEC */
 148         struct ip_fw_args args;
 149         int src_was_INADDR_ANY = 0;     /* as the name says... */
 150
 151         args.eh = NULL;
 152         args.rule = NULL;
 153         args.next_hop = NULL;
 154         args.divert_rule = 0;                   /* divert cookie */
 155
 156         /* Grab info from MT_TAG mbufs prepended to the chain. */
 157         while (m0 != NULL && m0->m_type == MT_TAG) {
 158                 switch(m0->_m_tag_id) {
 159                 case PACKET_TAG_DUMMYNET:
 160                         /*
 161                          * the packet was already tagged, so part of the
 162                          * processing was already done, and we need to go down.
 163                          * Get parameters from the header.
 164                          */
 165                         args.rule = ((struct dn_pkt *)m0)->rule;
 166                         opt = NULL ;
 167                         ro = &((struct dn_pkt *)m0)->ro;
 168                         imo = NULL ;
 169                         dst = ((struct dn_pkt *)m0)->dn_dst ;
 170                         ifp = ((struct dn_pkt *)m0)->ifp ;
 171                         flags = ((struct dn_pkt *)m0)->flags ;
 172                         break;
 173                 case PACKET_TAG_DIVERT:
 174                         args.divert_rule = (int)m0->m_data & 0xffff;
 175                         break;
 176                 case PACKET_TAG_IPFORWARD:
 177                         args.next_hop = (struct sockaddr_in *)m0->m_data;
 178                         break;
 179                 default:
 180                         printf("ip_output: unrecognised MT_TAG tag %d\n",
 181                             m0->_m_tag_id);
 182                         break;
 183                 }
 184                 m0 = m0->m_next;
 185         }
 186         m = m0;
 187         KASSERT(m != NULL && (m->m_flags & M_PKTHDR), ("ip_output: no HDR"));
 188
 189         if (ro == NULL) {
 190                 ro = &iproute;
 191                 bzero(ro, sizeof *ro);
 192         }
 193
 194         if (args.rule != NULL) {        /* dummynet already saw us */
 195                 ip = mtod(m, struct ip *);
 196                 hlen = IP_VHL_HL(ip->ip_vhl) << 2 ;
 197                 if (ro->ro_rt)
 198                         ia = ifatoia(ro->ro_rt->rt_ifa);
 199                 goto sendit;
 200         }
 201
 202         if (opt) {
 203                 len = 0;
 204                 m = ip_insertoptions(m, opt, &len);
 205                 if (len != 0)
 206                         hlen = len;
 207         }
 208         ip = mtod(m, struct ip *);
 209         pkt_dst = args.next_hop ? args.next_hop->sin_addr : ip->ip_dst;
 210
 211         /*
 212          * Fill in IP header.
 213          */
 214         if (!(flags & (IP_FORWARDING|IP_RAWOUTPUT))) {
 215                 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, hlen >> 2);
 216                 ip->ip_off &= IP_DF;
 217 #ifdef RANDOM_IP_ID
 218                 ip->ip_id = ip_randomid();
 219 #else
 220                 ip->ip_id = htons(ip_id++);
 221 #endif
 222                 ipstat.ips_localout++;
 223         } else {
 224                 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 225         }
 226
 227         dst = (struct sockaddr_in *)&ro->ro_dst;
 228         /*
 229          * If there is a cached route,
 230          * check that it is to the same destination
 231          * and is still up.  If not, free it and try again.
 232          * The address family should also be checked in case of sharing the
 233          * cache with IPv6.
 234          */
 235         if (ro->ro_rt &&
 236             (!(ro->ro_rt->rt_flags & RTF_UP) ||
 237              dst->sin_family != AF_INET ||
 238              dst->sin_addr.s_addr != pkt_dst.s_addr)) {
 239                 rtfree(ro->ro_rt);
 240                 ro->ro_rt = (struct rtentry *)NULL;
 241         }
 242         if (ro->ro_rt == NULL) {
 243                 bzero(dst, sizeof *dst);
 244                 dst->sin_family = AF_INET;
 245                 dst->sin_len = sizeof *dst;
 246                 dst->sin_addr = pkt_dst;
 247         }
 248         /*
 249          * If routing to interface only,
 250          * short circuit routing lookup.
 251          */
 252         if (flags & IP_ROUTETOIF) {
 253                 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL &&
 254                     (ia = ifatoia(ifa_ifwithnet(sintosa(dst)))) == NULL) {
 255                         ipstat.ips_noroute++;
 256                         error = ENETUNREACH;
 257                         goto bad;
 258                 }
 259                 ifp = ia->ia_ifp;
 260                 ip->ip_ttl = 1;
 261                 isbroadcast = in_broadcast(dst->sin_addr, ifp);
 262         } else if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) &&
 263                    imo != NULL && imo->imo_multicast_ifp != NULL) {
 264                 /*
 265                  * Bypass the normal routing lookup for multicast
 266                  * packets if the interface is specified.
 267                  */
 268                 ifp = imo->imo_multicast_ifp;
 269                 IFP_TO_IA(ifp, ia);
 270                 isbroadcast = 0;        /* fool gcc */
 271         } else {
 272                 /*
 273                  * If this is the case, we probably don't want to allocate
 274                  * a protocol-cloned route since we didn't get one from the
 275                  * ULP.  This lets TCP do its thing, while not burdening
 276                  * forwarding or ICMP with the overhead of cloning a route.
 277                  * Of course, we still want to do any cloning requested by
 278                  * the link layer, as this is probably required in all cases
 279                  * for correct operation (as it is for ARP).
 280                  */
 281                 if (ro->ro_rt == NULL)
 282                         rtalloc_ign(ro, RTF_PRCLONING);
 283                 if (ro->ro_rt == NULL) {
 284                         ipstat.ips_noroute++;
 285                         error = EHOSTUNREACH;
 286                         goto bad;
 287                 }
 288                 ia = ifatoia(ro->ro_rt->rt_ifa);
 289                 ifp = ro->ro_rt->rt_ifp;
 290                 ro->ro_rt->rt_use++;
 291                 if (ro->ro_rt->rt_flags & RTF_GATEWAY)
 292                         dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway;
 293                 if (ro->ro_rt->rt_flags & RTF_HOST)
 294                         isbroadcast = (ro->ro_rt->rt_flags & RTF_BROADCAST);
 295                 else
 296                         isbroadcast = in_broadcast(dst->sin_addr, ifp);
 297         }
 298         if (IN_MULTICAST(ntohl(pkt_dst.s_addr))) {
 299                 struct in_multi *inm;
 300
 301                 m->m_flags |= M_MCAST;
 302                 /*
 303                  * IP destination address is multicast.  Make sure "dst"
 304                  * still points to the address in "ro".  (It may have been
 305                  * changed to point to a gateway address, above.)
 306                  */
 307                 dst = (struct sockaddr_in *)&ro->ro_dst;
 308                 /*
 309                  * See if the caller provided any multicast options
 310                  */
 311                 if (imo != NULL) {
 312                         ip->ip_ttl = imo->imo_multicast_ttl;
 313                         if (imo->imo_multicast_vif != -1)
 314                                 ip->ip_src.s_addr =
 315                                     ip_mcast_src ?
 316                                     ip_mcast_src(imo->imo_multicast_vif) :
 317                                     INADDR_ANY;
 318                 } else
 319                         ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL;
 320                 /*
 321                  * Confirm that the outgoing interface supports multicast.
 322                  */
 323                 if ((imo == NULL) || (imo->imo_multicast_vif == -1)) {
 324                         if (!(ifp->if_flags & IFF_MULTICAST)) {
 325                                 ipstat.ips_noroute++;
 326                                 error = ENETUNREACH;
 327                                 goto bad;
 328                         }
 329                 }
 330                 /*
 331                  * If source address not specified yet, use address
 332                  * of outgoing interface.
 333                  */
 334                 if (ip->ip_src.s_addr == INADDR_ANY) {
 335                         /* Interface may have no addresses. */
 336                         if (ia != NULL)
 337                                 ip->ip_src = IA_SIN(ia)->sin_addr;
 338                 }
 339
 340                 IN_LOOKUP_MULTI(pkt_dst, ifp, inm);
 341                 if (inm != NULL &&
 342                    (imo == NULL || imo->imo_multicast_loop)) {
 343                         /*
 344                          * If we belong to the destination multicast group
 345                          * on the outgoing interface, and the caller did not
 346                          * forbid loopback, loop back a copy.
 347                          */
 348                         ip_mloopback(ifp, m, dst, hlen);
 349                 }
 350                 else {
 351                         /*
 352                          * If we are acting as a multicast router, perform
 353                          * multicast forwarding as if the packet had just
 354                          * arrived on the interface to which we are about
 355                          * to send.  The multicast forwarding function
 356                          * recursively calls this function, using the
 357                          * IP_FORWARDING flag to prevent infinite recursion.
 358                          *
 359                          * Multicasts that are looped back by ip_mloopback(),
 360                          * above, will be forwarded by the ip_input() routine,
 361                          * if necessary.
 362                          */
 363                         if (ip_mrouter && !(flags & IP_FORWARDING)) {
 364                                 /*
 365                                  * If rsvp daemon is not running, do not
 366                                  * set ip_moptions. This ensures that the packet
 367                                  * is multicast and not just sent down one link
 368                                  * as prescribed by rsvpd.
 369                                  */
 370                                 if (!rsvp_on)
 371                                         imo = NULL;
 372                                 if (ip_mforward &&
 373                                     ip_mforward(ip, ifp, m, imo) != 0) {
 374                                         m_freem(m);
 375                                         goto done;
 376                                 }
 377                         }
 378                 }
 379
 380                 /*
 381                  * Multicasts with a time-to-live of zero may be looped-
 382                  * back, above, but must not be transmitted on a network.
 383                  * Also, multicasts addressed to the loopback interface
 384                  * are not sent -- the above call to ip_mloopback() will
 385                  * loop back a copy if this host actually belongs to the
 386                  * destination group on the loopback interface.
 387                  */
 388                 if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) {
 389                         m_freem(m);
 390                         goto done;
 391                 }
 392
 393                 goto sendit;
 394         }
 395 #ifndef notdef
 396         /*
 397          * If the source address is not specified yet, use the address
 398          * of the outoing interface. In case, keep note we did that, so
 399          * if the the firewall changes the next-hop causing the output
 400          * interface to change, we can fix that.
 401          */
 402         if (ip->ip_src.s_addr == INADDR_ANY) {
 403                 /* Interface may have no addresses. */
 404                 if (ia != NULL) {
 405                         ip->ip_src = IA_SIN(ia)->sin_addr;
 406                         src_was_INADDR_ANY = 1;
 407                 }
 408         }
 409 #endif /* notdef */
 410 #ifdef ALTQ
 411         /*
 412          * Disable packet drop hack.
 413          * Packetdrop should be done by queueing.
 414          */
 415 #else /* !ALTQ */
 416         /*
 417          * Verify that we have any chance at all of being able to queue
 418          *      the packet or packet fragments
 419          */
 420         if ((ifp->if_snd.ifq_len + ip->ip_len / ifp->if_mtu + 1) >=
 421                 ifp->if_snd.ifq_maxlen) {
 422                         error = ENOBUFS;
 423                         ipstat.ips_odropped++;
 424                         goto bad;
 425         }
 426 #endif /* !ALTQ */
 427
 428         /*
 429          * Look for broadcast address and
 430          * verify user is allowed to send
 431          * such a packet.
 432          */
 433         if (isbroadcast) {
 434                 if (!(ifp->if_flags & IFF_BROADCAST)) {
 435                         error = EADDRNOTAVAIL;
 436                         goto bad;
 437                 }
 438                 if (!(flags & IP_ALLOWBROADCAST)) {
 439                         error = EACCES;
 440                         goto bad;
 441                 }
 442                 /* don't allow broadcast messages to be fragmented */
 443                 if (ip->ip_len > ifp->if_mtu) {
 444                         error = EMSGSIZE;
 445                         goto bad;
 446                 }
 447                 m->m_flags |= M_BCAST;
 448         } else {
 449                 m->m_flags &= ~M_BCAST;
 450         }
 451
 452 sendit:
 453 #ifdef IPSEC
 454         /* get SP for this packet */
 455         if (so == NULL)
 456                 sp = ipsec4_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, flags, &error);
 457         else
 458                 sp = ipsec4_getpolicybysock(m, IPSEC_DIR_OUTBOUND, so, &error);
 459
 460         if (sp == NULL) {
 461                 ipsecstat.out_inval++;
 462                 goto bad;
 463         }
 464
 465         error = 0;
 466
 467         /* check policy */
 468         switch (sp->policy) {
 469         case IPSEC_POLICY_DISCARD:
 470                 /*
 471                  * This packet is just discarded.
 472                  */
 473                 ipsecstat.out_polvio++;
 474                 goto bad;
 475
 476         case IPSEC_POLICY_BYPASS:
 477         case IPSEC_POLICY_NONE:
 478                 /* no need to do IPsec. */
 479                 goto skip_ipsec;
 480
 481         case IPSEC_POLICY_IPSEC:
 482                 if (sp->req == NULL) {
 483                         /* acquire a policy */
 484                         error = key_spdacquire(sp);
 485                         goto bad;
 486                 }
 487                 break;
 488
 489         case IPSEC_POLICY_ENTRUST:
 490         default:
 491                 printf("ip_output: Invalid policy found. %d\n", sp->policy);
 492         }
 493     {
 494         struct ipsec_output_state state;
 495         bzero(&state, sizeof state);
 496         state.m = m;
 497         if (flags & IP_ROUTETOIF) {
 498                 state.ro = &iproute;
 499                 bzero(&iproute, sizeof iproute);
 500         } else
 501                 state.ro = ro;
 502         state.dst = (struct sockaddr *)dst;
 503
 504         ip->ip_sum = 0;
 505
 506         /*
 507          * XXX
 508          * delayed checksums are not currently compatible with IPsec
 509          */
 510         if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 511                 in_delayed_cksum(m);
 512                 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
 513         }
 514
 515         ip->ip_len = htons(ip->ip_len);
 516         ip->ip_off = htons(ip->ip_off);
 517
 518         error = ipsec4_output(&state, sp, flags);
 519
 520         m = state.m;
 521         if (flags & IP_ROUTETOIF) {
 522                 /*
 523                  * if we have tunnel mode SA, we may need to ignore
 524                  * IP_ROUTETOIF.
 525                  */
 526                 if (state.ro != &iproute || state.ro->ro_rt != NULL) {
 527                         flags &= ~IP_ROUTETOIF;
 528                         ro = state.ro;
 529                 }
 530         } else
 531                 ro = state.ro;
 532         dst = (struct sockaddr_in *)state.dst;
 533         if (error) {
 534                 /* mbuf is already reclaimed in ipsec4_output. */
 535                 m0 = NULL;
 536                 switch (error) {
 537                 case EHOSTUNREACH:
 538                 case ENETUNREACH:
 539                 case EMSGSIZE:
 540                 case ENOBUFS:
 541                 case ENOMEM:
 542                         break;
 543                 default:
 544                         printf("ip4_output (ipsec): error code %d\n", error);
 545                         /*fall through*/
 546                 case ENOENT:
 547                         /* don't show these error codes to the user */
 548                         error = 0;
 549                         break;
 550                 }
 551                 goto bad;
 552         }
 553     }
 554
 555         /* be sure to update variables that are affected by ipsec4_output() */
 556         ip = mtod(m, struct ip *);
 557 #ifdef _IP_VHL
 558         hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 559 #else
 560         hlen = ip->ip_hl << 2;
 561 #endif
 562         if (ro->ro_rt == NULL) {
 563                 if (!(flags & IP_ROUTETOIF)) {
 564                         printf("ip_output: "
 565                                 "can't update route after IPsec processing\n");
 566                         error = EHOSTUNREACH;   /*XXX*/
 567                         goto bad;
 568                 }
 569         } else {
 570                 ia = ifatoia(ro->ro_rt->rt_ifa);
 571                 ifp = ro->ro_rt->rt_ifp;
 572         }
 573
 574         /* make it flipped, again. */
 575         ip->ip_len = ntohs(ip->ip_len);
 576         ip->ip_off = ntohs(ip->ip_off);
 577 skip_ipsec:
 578 #endif /*IPSEC*/
 579 #ifdef FAST_IPSEC
 580         /*
 581          * Check the security policy (SP) for the packet and, if
 582          * required, do IPsec-related processing.  There are two
 583          * cases here; the first time a packet is sent through
 584          * it will be untagged and handled by ipsec4_checkpolicy.
 585          * If the packet is resubmitted to ip_output (e.g. after
 586          * AH, ESP, etc. processing), there will be a tag to bypass
 587          * the lookup and related policy checking.
 588          */
 589         mtag = m_tag_find(m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
 590         s = splnet();
 591         if (mtag != NULL) {
 592                 tdbi = (struct tdb_ident *)(mtag + 1);
 593                 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
 594                 if (sp == NULL)
 595                         error = -EINVAL;        /* force silent drop */
 596                 m_tag_delete(m, mtag);
 597         } else {
 598                 sp = ipsec4_checkpolicy(m, IPSEC_DIR_OUTBOUND, flags,
 599                                         &error, inp);
 600         }
 601         /*
 602          * There are four return cases:
 603          *    sp != NULL                    apply IPsec policy
 604          *    sp == NULL, error == 0        no IPsec handling needed
 605          *    sp == NULL, error == -EINVAL  discard packet w/o error
 606          *    sp == NULL, error != 0        discard packet, report error
 607          */
 608         if (sp != NULL) {
 609                 /* Loop detection, check if ipsec processing already done */
 610                 KASSERT(sp->req != NULL, ("ip_output: no ipsec request"));
 611                 for (mtag = m_tag_first(m); mtag != NULL;
 612                      mtag = m_tag_next(m, mtag)) {
 613                         if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
 614                                 continue;
 615                         if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
 616                             mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
 617                                 continue;
 618                         /*
 619                          * Check if policy has an SA associated with it.
 620                          * This can happen when an SP has yet to acquire
 621                          * an SA; e.g. on first reference.  If it occurs,
 622                          * then we let ipsec4_process_packet do its thing.
 623                          */
 624                         if (sp->req->sav == NULL)
 625                                 break;
 626                         tdbi = (struct tdb_ident *)(mtag + 1);
 627                         if (tdbi->spi == sp->req->sav->spi &&
 628                             tdbi->proto == sp->req->sav->sah->saidx.proto &&
 629                             bcmp(&tdbi->dst, &sp->req->sav->sah->saidx.dst,
 630                                  sizeof(union sockaddr_union)) == 0) {
 631                                 /*
 632                                  * No IPsec processing is needed, free
 633                                  * reference to SP.
 634                                  *
 635                                  * NB: null pointer to avoid free at
 636                                  *     done: below.
 637                                  */
 638                                 KEY_FREESP(&sp), sp = NULL;
 639                                 splx(s);
 640                                 goto spd_done;
 641                         }
 642                 }
 643
 644                 /*
 645                  * Do delayed checksums now because we send before
 646                  * this is done in the normal processing path.
 647                  */
 648                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 649                         in_delayed_cksum(m);
 650                         m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
 651                 }
 652
 653                 ip->ip_len = htons(ip->ip_len);
 654                 ip->ip_off = htons(ip->ip_off);
 655
 656                 /* NB: callee frees mbuf */
 657                 error = ipsec4_process_packet(m, sp->req, flags, 0);
 658                 /*
 659                  * Preserve KAME behaviour: ENOENT can be returned
 660                  * when an SA acquire is in progress.  Don't propagate
 661                  * this to user-level; it confuses applications.
 662                  *
 663                  * XXX this will go away when the SADB is redone.
 664                  */
 665                 if (error == ENOENT)
 666                         error = 0;
 667                 splx(s);
 668                 goto done;
 669         } else {
 670                 splx(s);
 671
 672                 if (error != 0) {
 673                         /*
 674                          * Hack: -EINVAL is used to signal that a packet
 675                          * should be silently discarded.  This is typically
 676                          * because we asked key management for an SA and
 677                          * it was delayed (e.g. kicked up to IKE).
 678                          */
 679                         if (error == -EINVAL)
 680                                 error = 0;
 681                         goto bad;
 682                 } else {
 683                         /* No IPsec processing for this packet. */
 684                 }
 685 #ifdef notyet
 686                 /*
 687                  * If deferred crypto processing is needed, check that
 688                  * the interface supports it.
 689                  */
 690                 mtag = m_tag_find(m, PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED, NULL);
 691                 if (mtag != NULL && !(ifp->if_capenable & IFCAP_IPSEC)) {
 692                         /* notify IPsec to do its own crypto */
 693                         ipsp_skipcrypto_unmark((struct tdb_ident *)(mtag + 1));
 694                         error = EHOSTUNREACH;
 695                         goto bad;
 696                 }
 697 #endif
 698         }
 699 spd_done:
 700 #endif /* FAST_IPSEC */
 701         /*
 702          * IpHack's section.
 703          * - Xlate: translate packet's addr/port (NAT).
 704          * - Firewall: deny/allow/etc.
 705          * - Wrap: fake packet's addr/port <unimpl.>
 706          * - Encapsulate: put it in another IP and send out. <unimp.>
 707          */
 708
 709         /*
 710          * Run through list of hooks for output packets.
 711          */
 712         if (pfil_has_hooks(&inet_pfil_hook)) {
 713                 error = pfil_run_hooks(&inet_pfil_hook, &m, ifp, PFIL_OUT);
 714                 if (error != 0 || m == NULL)
 715                         goto done;
 716                 ip = mtod(m, struct ip *);
 717         }
 718
 719         /*
 720          * Check with the firewall...
 721          * but not if we are already being fwd'd from a firewall.
 722          */
 723         if (fw_enable && IPFW_LOADED && !args.next_hop) {
 724                 struct sockaddr_in *old = dst;
 725
 726                 args.m = m;
 727                 args.next_hop = dst;
 728                 args.oif = ifp;
 729                 off = ip_fw_chk_ptr(&args);
 730                 m = args.m;
 731                 dst = args.next_hop;
 732
 733                 /*
 734                  * On return we must do the following:
 735                  * m == NULL    -> drop the pkt (old interface, deprecated)
 736                  * (off & IP_FW_PORT_DENY_FLAG) -> drop the pkt (new interface)
 737                  * 1<=off<= 0xffff              -> DIVERT
 738                  * (off & IP_FW_PORT_DYNT_FLAG) -> send to a DUMMYNET pipe
 739                  * (off & IP_FW_PORT_TEE_FLAG)  -> TEE the packet
 740                  * dst != old                   -> IPFIREWALL_FORWARD
 741                  * off==0, dst==old             -> accept
 742                  * If some of the above modules are not compiled in, then
 743                  * we should't have to check the corresponding condition
 744                  * (because the ipfw control socket should not accept
 745                  * unsupported rules), but better play safe and drop
 746                  * packets in case of doubt.
 747                  */
 748                 if ( (off & IP_FW_PORT_DENY_FLAG) || m == NULL) {
 749                         if (m)
 750                                 m_freem(m);
 751                         error = EACCES;
 752                         goto done;
 753                 }
 754                 ip = mtod(m, struct ip *);
 755                 if (off == 0 && dst == old)             /* common case */
 756                         goto pass;
 757                 if (DUMMYNET_LOADED && (off & IP_FW_PORT_DYNT_FLAG)) {
 758                         /*
 759                          * pass the pkt to dummynet. Need to include
 760                          * pipe number, m, ifp, ro, dst because these are
 761                          * not recomputed in the next pass.
 762                          * All other parameters have been already used and
 763                          * so they are not needed anymore.
 764                          * XXX note: if the ifp or ro entry are deleted
 765                          * while a pkt is in dummynet, we are in trouble!
 766                          */
 767                         args.ro = ro;
 768                         args.dst = dst;
 769                         args.flags = flags;
 770
 771                         error = ip_dn_io_ptr(m, off & 0xffff, DN_TO_IP_OUT,
 772                                 &args);
 773                         goto done;
 774                 }
 775 #ifdef IPDIVERT
 776                 if (off != 0 && !(off & IP_FW_PORT_DYNT_FLAG)) {
 777                         struct mbuf *clone = NULL;
 778
 779                         /* Clone packet if we're doing a 'tee' */
 780                         if ((off & IP_FW_PORT_TEE_FLAG))
 781                                 clone = m_dup(m, MB_DONTWAIT);
 782
 783                         /*
 784                          * XXX
 785                          * delayed checksums are not currently compatible
 786                          * with divert sockets.
 787                          */
 788                         if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 789                                 in_delayed_cksum(m);
 790                                 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
 791                         }
 792
 793                         /* Restore packet header fields to original values */
 794                         ip->ip_len = htons(ip->ip_len);
 795                         ip->ip_off = htons(ip->ip_off);
 796
 797                         /* Deliver packet to divert input routine */
 798                         divert_packet(m, 0, off & 0xffff, args.divert_rule);
 799
 800                         /* If 'tee', continue with original packet */
 801                         if (clone != NULL) {
 802                                 m = clone;
 803                                 ip = mtod(m, struct ip *);
 804                                 goto pass;
 805                         }
 806                         goto done;
 807                 }
 808 #endif
 809
 810                 /* IPFIREWALL_FORWARD */
 811                 /*
 812                  * Check dst to make sure it is directly reachable on the
 813                  * interface we previously thought it was.
 814                  * If it isn't (which may be likely in some situations) we have
 815                  * to re-route it (ie, find a route for the next-hop and the
 816                  * associated interface) and set them here. This is nested
 817                  * forwarding which in most cases is undesirable, except where
 818                  * such control is nigh impossible. So we do it here.
 819                  * And I'm babbling.
 820                  */
 821                 if (off == 0 && old != dst) { /* FORWARD, dst has changed */
 822 #if 0
 823                         /*
 824                          * XXX To improve readability, this block should be
 825                          * changed into a function call as below:
 826                          */
 827                         error = ip_ipforward(&m, &dst, &ifp);
 828                         if (error)
 829                                 goto bad;
 830                         if (m == NULL) /* ip_input consumed the mbuf */
 831                                 goto done;
 832 #else
 833                         struct in_ifaddr *ia;
 834
 835                         /*
 836                          * XXX sro_fwd below is static, and a pointer
 837                          * to it gets passed to routines downstream.
 838                          * This could have surprisingly bad results in
 839                          * practice, because its content is overwritten
 840                          * by subsequent packets.
 841                          */
 842                         /* There must be a better way to do this next line... */
 843                         static struct route sro_fwd;
 844                         struct route *ro_fwd = &sro_fwd;
 845
 846 #if 0
 847                         print_ip("IPFIREWALL_FORWARD: New dst ip: ",
 848                             dst->sin_addr, "\n");
 849 #endif
 850
 851                         /*
 852                          * We need to figure out if we have been forwarded
 853                          * to a local socket. If so, then we should somehow
 854                          * "loop back" to ip_input, and get directed to the
 855                          * PCB as if we had received this packet. This is
 856                          * because it may be dificult to identify the packets
 857                          * you want to forward until they are being output
 858                          * and have selected an interface. (e.g. locally
 859                          * initiated packets) If we used the loopback inteface,
 860                          * we would not be able to control what happens
 861                          * as the packet runs through ip_input() as
 862                          * it is done through a ISR.
 863                          */
 864                         LIST_FOREACH(ia, INADDR_HASH(dst->sin_addr.s_addr),
 865                                      ia_hash) {
 866                                 /*
 867                                  * If the addr to forward to is one
 868                                  * of ours, we pretend to
 869                                  * be the destination for this packet.
 870                                  */
 871                                 if (IA_SIN(ia)->sin_addr.s_addr ==
 872                                                  dst->sin_addr.s_addr)
 873                                         break;
 874                         }
 875                         if (ia != NULL) {    /* tell ip_input "dont filter" */
 876                                 struct m_hdr tag;
 877
 878                                 tag.mh_type = MT_TAG;
 879                                 tag.mh_flags = PACKET_TAG_IPFORWARD;
 880                                 tag.mh_data = (caddr_t)args.next_hop;
 881                                 tag.mh_next = m;
 882
 883                                 if (m->m_pkthdr.rcvif == NULL)
 884                                         m->m_pkthdr.rcvif = ifunit("lo0");
 885                                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 886                                         m->m_pkthdr.csum_flags |=
 887                                             CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
 888                                         m0->m_pkthdr.csum_data = 0xffff;
 889                                 }
 890                                 m->m_pkthdr.csum_flags |=
 891                                     CSUM_IP_CHECKED | CSUM_IP_VALID;
 892                                 ip->ip_len = htons(ip->ip_len);
 893                                 ip->ip_off = htons(ip->ip_off);
 894                                 ip_input((struct mbuf *)&tag);
 895                                 goto done;
 896                         }
 897                         /* Some of the logic for this was nicked from above.
 898                          *
 899                          * This rewrites the cached route in a local PCB.
 900                          * Is this what we want to do?
 901                          */
 902                         bcopy(dst, &ro_fwd->ro_dst, sizeof *dst);
 903                         ro_fwd->ro_rt = NULL;
 904
 905                         rtalloc_ign(ro_fwd, RTF_PRCLONING);
 906                         if (ro_fwd->ro_rt == NULL) {
 907                                 ipstat.ips_noroute++;
 908                                 error = EHOSTUNREACH;
 909                                 goto bad;
 910                         }
 911
 912                         ia = ifatoia(ro_fwd->ro_rt->rt_ifa);
 913                         ifp = ro_fwd->ro_rt->rt_ifp;
 914                         ro_fwd->ro_rt->rt_use++;
 915                         if (ro_fwd->ro_rt->rt_flags & RTF_GATEWAY)
 916                                 dst = (struct sockaddr_in *)
 917                                     ro_fwd->ro_rt->rt_gateway;
 918                         if (ro_fwd->ro_rt->rt_flags & RTF_HOST)
 919                                 isbroadcast =
 920                                     (ro_fwd->ro_rt->rt_flags & RTF_BROADCAST);
 921                         else
 922                                 isbroadcast = in_broadcast(dst->sin_addr, ifp);
 923                         if (ro->ro_rt != NULL)
 924                                 rtfree(ro->ro_rt);
 925                         ro->ro_rt = ro_fwd->ro_rt;
 926                         dst = (struct sockaddr_in *)&ro_fwd->ro_dst;
 927
 928 #endif  /* ... block to be put into a function */
 929                         /*
 930                          * If we added a default src ip earlier,
 931                          * which would have been gotten from the-then
 932                          * interface, do it again, from the new one.
 933                          */
 934                         if (src_was_INADDR_ANY)
 935                                 ip->ip_src = IA_SIN(ia)->sin_addr;
 936                         goto pass ;
 937                 }
 938
 939                 /*
 940                  * if we get here, none of the above matches, and
 941                  * we have to drop the pkt
 942                  */
 943                 m_freem(m);
 944                 error = EACCES; /* not sure this is the right error msg */
 945                 goto done;
 946         }
 947
 948 pass:
 949         /* 127/8 must not appear on wire - RFC1122. */
 950         if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
 951             (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
 952                 if (!(ifp->if_flags & IFF_LOOPBACK)) {
 953                         ipstat.ips_badaddr++;
 954                         error = EADDRNOTAVAIL;
 955                         goto bad;
 956                 }
 957         }
 958
 959         m->m_pkthdr.csum_flags |= CSUM_IP;
 960         sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_hwassist;
 961         if (sw_csum & CSUM_DELAY_DATA) {
 962                 in_delayed_cksum(m);
 963                 sw_csum &= ~CSUM_DELAY_DATA;
 964         }
 965         m->m_pkthdr.csum_flags &= ifp->if_hwassist;
 966
 967         /*
 968          * If small enough for interface, or the interface will take
 969          * care of the fragmentation for us, can just send directly.
 970          */
 971         if (ip->ip_len <= ifp->if_mtu || ((ifp->if_hwassist & CSUM_FRAGMENT) &&
 972             !(ip->ip_off & IP_DF))) {
 973                 ip->ip_len = htons(ip->ip_len);
 974                 ip->ip_off = htons(ip->ip_off);
 975                 ip->ip_sum = 0;
 976                 if (sw_csum & CSUM_DELAY_IP) {
 977                         if (ip->ip_vhl == IP_VHL_BORING) {
 978                                 ip->ip_sum = in_cksum_hdr(ip);
 979                         } else {
 980                                 ip->ip_sum = in_cksum(m, hlen);
 981                         }
 982                 }
 983
 984                 /* Record statistics for this interface address. */
 985                 if (!(flags & IP_FORWARDING) && ia) {
 986                         ia->ia_ifa.if_opackets++;
 987                         ia->ia_ifa.if_obytes += m->m_pkthdr.len;
 988                 }
 989
 990 #ifdef IPSEC
 991                 /* clean ipsec history once it goes out of the node */
 992                 ipsec_delaux(m);
 993 #endif
 994
 995 #ifdef MBUF_STRESS_TEST
 996                 if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size) {
 997                         struct mbuf *m1, *m2;
 998                         int length, tmp;
 999
1000                         tmp = length = m->m_pkthdr.len;
1001
1002                         while ((length -= mbuf_frag_size) >= 1) {
1003                                 m1 = m_split(m, length, MB_DONTWAIT);
1004                                 if (m1 == NULL)
1005                                         break;
1006                                 m1->m_flags &= ~M_PKTHDR;
1007                                 m2 = m;
1008                                 while (m2->m_next != NULL)
1009                                         m2 = m2->m_next;
1010                                 m2->m_next = m1;
1011                         }
1012                         m->m_pkthdr.len = tmp;
1013                 }
1014 #endif
1015                 error = (*ifp->if_output)(ifp, m, (struct sockaddr *)dst,
1016                                           ro->ro_rt);
1017                 goto done;
1018         }
1019
1020         if (ip->ip_off & IP_DF) {
1021                 error = EMSGSIZE;
1022                 /*
1023                  * This case can happen if the user changed the MTU
1024                  * of an interface after enabling IP on it.  Because
1025                  * most netifs don't keep track of routes pointing to
1026                  * them, there is no way for one to update all its
1027                  * routes when the MTU is changed.
1028                  */
1029                 if ((ro->ro_rt->rt_flags & (RTF_UP | RTF_HOST)) &&
1030                     !(ro->ro_rt->rt_rmx.rmx_locks & RTV_MTU) &&
1031                     (ro->ro_rt->rt_rmx.rmx_mtu > ifp->if_mtu)) {
1032                         ro->ro_rt->rt_rmx.rmx_mtu = ifp->if_mtu;
1033                 }
1034                 ipstat.ips_cantfrag++;
1035                 goto bad;
1036         }
1037
1038         /*
1039          * Too large for interface; fragment if possible. If successful,
1040          * on return, m will point to a list of packets to be sent.
1041          */
1042         error = ip_fragment(ip, &m, ifp->if_mtu, ifp->if_hwassist, sw_csum);
1043         if (error)
1044                 goto bad;
1045         for (; m; m = m0) {
1046                 m0 = m->m_nextpkt;
1047                 m->m_nextpkt = NULL;
1048 #ifdef IPSEC
1049                 /* clean ipsec history once it goes out of the node */
1050                 ipsec_delaux(m);
1051 #endif
1052                 if (error == 0) {
1053                         /* Record statistics for this interface address. */
1054                         if (ia != NULL) {
1055                                 ia->ia_ifa.if_opackets++;
1056                                 ia->ia_ifa.if_obytes += m->m_pkthdr.len;
1057                         }
1058                         error = (*ifp->if_output)(ifp, m,
1059                                                   (struct sockaddr *)dst,
1060                                                   ro->ro_rt);
1061                 } else
1062                         m_freem(m);
1063         }
1064
1065         if (error == 0)
1066                 ipstat.ips_fragmented++;
1067
1068 done:
1069         if (ro == &iproute && ro->ro_rt != NULL) {
1070                 RTFREE(ro->ro_rt);
1071                 ro->ro_rt = NULL;
1072         }
1073 #ifdef IPSEC
1074         if (sp != NULL) {
1075                 KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
1076                         printf("DP ip_output call free SP:%p\n", sp));
1077                 key_freesp(sp);
1078         }
1079 #endif
1080 #ifdef FAST_IPSEC
1081         if (sp != NULL)
1082                 KEY_FREESP(&sp);
1083 #endif
1084         return (error);
1085 bad:
1086         m_freem(m);
1087         goto done;
1088 }
1089
1090 /*
1091  * Create a chain of fragments which fit the given mtu. m_frag points to the
1092  * mbuf to be fragmented; on return it points to the chain with the fragments.
1093  * Return 0 if no error. If error, m_frag may contain a partially built
1094  * chain of fragments that should be freed by the caller.
1095  *
1096  * if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist)
1097  * sw_csum contains the delayed checksums flags (e.g., CSUM_DELAY_IP).
1098  */
1099 int
1100 ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu,
1101             u_long if_hwassist_flags, int sw_csum)
1102 {
1103         int error = 0;
1104         int hlen = IP_VHL_HL(ip->ip_vhl) << 2;
1105         int len = (mtu - hlen) & ~7;    /* size of payload in each fragment */
1106         int off;
1107         struct mbuf *m0 = *m_frag;      /* the original packet          */
1108         int firstlen;
1109         struct mbuf **mnext;
1110         int nfrags;
1111
1112         if (ip->ip_off & IP_DF) {       /* Fragmentation not allowed */
1113                 ipstat.ips_cantfrag++;
1114                 return EMSGSIZE;
1115         }
1116
1117         /*
1118          * Must be able to put at least 8 bytes per fragment.
1119          */
1120         if (len < 8)
1121                 return EMSGSIZE;
1122
1123         /*
1124          * If the interface will not calculate checksums on
1125          * fragmented packets, then do it here.
1126          */
1127         if ((m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA) &&
1128             !(if_hwassist_flags & CSUM_IP_FRAGS)) {
1129                 in_delayed_cksum(m0);
1130                 m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
1131         }
1132
1133         if (len > PAGE_SIZE) {
1134                 /*
1135                  * Fragment large datagrams such that each segment
1136                  * contains a multiple of PAGE_SIZE amount of data,
1137                  * plus headers. This enables a receiver to perform
1138                  * page-flipping zero-copy optimizations.
1139                  *
1140                  * XXX When does this help given that sender and receiver
1141                  * could have different page sizes, and also mtu could
1142                  * be less than the receiver's page size ?
1143                  */
1144                 int newlen;
1145                 struct mbuf *m;
1146
1147                 for (m = m0, off = 0; m && (off+m->m_len) <= mtu; m = m->m_next)
1148                         off += m->m_len;
1149
1150                 /*
1151                  * firstlen (off - hlen) must be aligned on an
1152                  * 8-byte boundary
1153                  */
1154                 if (off < hlen)
1155                         goto smart_frag_failure;
1156                 off = ((off - hlen) & ~7) + hlen;
1157                 newlen = (~PAGE_MASK) & mtu;
1158                 if ((newlen + sizeof(struct ip)) > mtu) {
1159                         /* we failed, go back the default */
1160 smart_frag_failure:
1161                         newlen = len;
1162                         off = hlen + len;
1163                 }
1164                 len = newlen;
1165
1166         } else {
1167                 off = hlen + len;
1168         }
1169
1170         firstlen = off - hlen;
1171         mnext = &m0->m_nextpkt;         /* pointer to next packet */
1172
1173         /*
1174          * Loop through length of segment after first fragment,
1175          * make new header and copy data of each part and link onto chain.
1176          * Here, m0 is the original packet, m is the fragment being created.
1177          * The fragments are linked off the m_nextpkt of the original
1178          * packet, which after processing serves as the first fragment.
1179          */
1180         for (nfrags = 1; off < ip->ip_len; off += len, nfrags++) {
1181                 struct ip *mhip;        /* ip header on the fragment */
1182                 struct mbuf *m;
1183                 int mhlen = sizeof(struct ip);
1184
1185                 MGETHDR(m, MB_DONTWAIT, MT_HEADER);
1186                 if (m == NULL) {
1187                         error = ENOBUFS;
1188                         ipstat.ips_odropped++;
1189                         goto done;
1190                 }
1191                 m->m_flags |= (m0->m_flags & M_MCAST) | M_FRAG;
1192                 /*
1193                  * In the first mbuf, leave room for the link header, then
1194                  * copy the original IP header including options. The payload
1195                  * goes into an additional mbuf chain returned by m_copy().
1196                  */
1197                 m->m_data += max_linkhdr;
1198                 mhip = mtod(m, struct ip *);
1199                 *mhip = *ip;
1200                 if (hlen > sizeof(struct ip)) {
1201                         mhlen = ip_optcopy(ip, mhip) + sizeof(struct ip);
1202                         mhip->ip_vhl = IP_MAKE_VHL(IPVERSION, mhlen >> 2);
1203                 }
1204                 m->m_len = mhlen;
1205                 /* XXX do we need to add ip->ip_off below ? */
1206                 mhip->ip_off = ((off - hlen) >> 3) + ip->ip_off;
1207                 if (off + len >= ip->ip_len) {  /* last fragment */
1208                         len = ip->ip_len - off;
1209                         m->m_flags |= M_LASTFRAG;
1210                 } else
1211                         mhip->ip_off |= IP_MF;
1212                 mhip->ip_len = htons((u_short)(len + mhlen));
1213                 m->m_next = m_copy(m0, off, len);
1214                 if (m->m_next == NULL) {                /* copy failed */
1215                         m_free(m);
1216                         error = ENOBUFS;        /* ??? */
1217                         ipstat.ips_odropped++;
1218                         goto done;
1219                 }
1220                 m->m_pkthdr.len = mhlen + len;
1221                 m->m_pkthdr.rcvif = (struct ifnet *)NULL;
1222                 m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags;
1223                 mhip->ip_off = htons(mhip->ip_off);
1224                 mhip->ip_sum = 0;
1225                 if (sw_csum & CSUM_DELAY_IP)
1226                         mhip->ip_sum = in_cksum(m, mhlen);
1227                 *mnext = m;
1228                 mnext = &m->m_nextpkt;
1229         }
1230         ipstat.ips_ofragments += nfrags;
1231
1232         /* set first marker for fragment chain */
1233         m0->m_flags |= M_FIRSTFRAG | M_FRAG;
1234         m0->m_pkthdr.csum_data = nfrags;
1235
1236         /*
1237          * Update first fragment by trimming what's been copied out
1238          * and updating header.
1239          */
1240         m_adj(m0, hlen + firstlen - ip->ip_len);
1241         m0->m_pkthdr.len = hlen + firstlen;
1242         ip->ip_len = htons((u_short)m0->m_pkthdr.len);
1243         ip->ip_off |= IP_MF;
1244         ip->ip_off = htons(ip->ip_off);
1245         ip->ip_sum = 0;
1246         if (sw_csum & CSUM_DELAY_IP)
1247                 ip->ip_sum = in_cksum(m0, hlen);
1248
1249 done:
1250         *m_frag = m0;
1251         return error;
1252 }
1253
1254 void
1255 in_delayed_cksum(struct mbuf *m)
1256 {
1257         struct ip *ip;
1258         u_short csum, offset;
1259
1260         ip = mtod(m, struct ip *);
1261         offset = IP_VHL_HL(ip->ip_vhl) << 2 ;
1262         csum = in_cksum_skip(m, ip->ip_len, offset);
1263         if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0)
1264                 csum = 0xffff;
1265         offset += m->m_pkthdr.csum_data;        /* checksum offset */
1266
1267         if (offset + sizeof(u_short) > m->m_len) {
1268                 printf("delayed m_pullup, m->len: %d  off: %d  p: %d\n",
1269                     m->m_len, offset, ip->ip_p);
1270                 /*
1271                  * XXX
1272                  * this shouldn't happen, but if it does, the
1273                  * correct behavior may be to insert the checksum
1274                  * in the existing chain instead of rearranging it.
1275                  */
1276                 m = m_pullup(m, offset + sizeof(u_short));
1277         }
1278         *(u_short *)(m->m_data + offset) = csum;
1279 }
1280
1281 /*
1282  * Insert IP options into preformed packet.
1283  * Adjust IP destination as required for IP source routing,
1284  * as indicated by a non-zero in_addr at the start of the options.
1285  *
1286  * XXX This routine assumes that the packet has no options in place.
1287  */
1288 static struct mbuf *
1289 ip_insertoptions(struct mbuf *m, struct mbuf *opt, int *phlen)
1290 {
1291         struct ipoption *p = mtod(opt, struct ipoption *);
1292         struct mbuf *n;
1293         struct ip *ip = mtod(m, struct ip *);
1294         unsigned optlen;
1295
1296         optlen = opt->m_len - sizeof p->ipopt_dst;
1297         if (optlen + (u_short)ip->ip_len > IP_MAXPACKET) {
1298                 *phlen = 0;
1299                 return (m);             /* XXX should fail */
1300         }
1301         if (p->ipopt_dst.s_addr)
1302                 ip->ip_dst = p->ipopt_dst;
1303         if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) {
1304                 MGETHDR(n, MB_DONTWAIT, MT_HEADER);
1305                 if (n == NULL) {
1306                         *phlen = 0;
1307                         return (m);
1308                 }
1309                 n->m_pkthdr.rcvif = (struct ifnet *)NULL;
1310                 n->m_pkthdr.len = m->m_pkthdr.len + optlen;
1311                 m->m_len -= sizeof(struct ip);
1312                 m->m_data += sizeof(struct ip);
1313                 n->m_next = m;
1314                 m = n;
1315                 m->m_len = optlen + sizeof(struct ip);
1316                 m->m_data += max_linkhdr;
1317                 memcpy(mtod(m, void *), ip, sizeof(struct ip));
1318         } else {
1319                 m->m_data -= optlen;
1320                 m->m_len += optlen;
1321                 m->m_pkthdr.len += optlen;
1322                 ovbcopy(ip, mtod(m, caddr_t), sizeof(struct ip));
1323         }
1324         ip = mtod(m, struct ip *);
1325         bcopy(p->ipopt_list, ip + 1, optlen);
1326         *phlen = sizeof(struct ip) + optlen;
1327         ip->ip_vhl = IP_MAKE_VHL(IPVERSION, *phlen >> 2);
1328         ip->ip_len += optlen;
1329         return (m);
1330 }
1331
1332 /*
1333  * Copy options from ip to jp,
1334  * omitting those not copied during fragmentation.
1335  */
1336 int
1337 ip_optcopy(struct ip *ip, struct ip *jp)
1338 {
1339         u_char *cp, *dp;
1340         int opt, optlen, cnt;
1341
1342         cp = (u_char *)(ip + 1);
1343         dp = (u_char *)(jp + 1);
1344         cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip);
1345         for (; cnt > 0; cnt -= optlen, cp += optlen) {
1346                 opt = cp[0];
1347                 if (opt == IPOPT_EOL)
1348                         break;
1349                 if (opt == IPOPT_NOP) {
1350                         /* Preserve for IP mcast tunnel's LSRR alignment. */
1351                         *dp++ = IPOPT_NOP;
1352                         optlen = 1;
1353                         continue;
1354                 }
1355
1356                 KASSERT(cnt >= IPOPT_OLEN + sizeof *cp,
1357                     ("ip_optcopy: malformed ipv4 option"));
1358                 optlen = cp[IPOPT_OLEN];
1359                 KASSERT(optlen >= IPOPT_OLEN + sizeof *cp && optlen <= cnt,
1360                     ("ip_optcopy: malformed ipv4 option"));
1361
1362                 /* bogus lengths should have been caught by ip_dooptions */
1363                 if (optlen > cnt)
1364                         optlen = cnt;
1365                 if (IPOPT_COPIED(opt)) {
1366                         bcopy(cp, dp, optlen);
1367                         dp += optlen;
1368                 }
1369         }
1370         for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++)
1371                 *dp++ = IPOPT_EOL;
1372         return (optlen);
1373 }
1374
1375 /*
1376  * IP socket option processing.
1377  */
1378 int
1379 ip_ctloutput(struct socket *so, struct sockopt *sopt)
1380 {
1381         struct  inpcb *inp = so->so_pcb;
1382         int     error, optval;
1383
1384         error = optval = 0;
1385         if (sopt->sopt_level != IPPROTO_IP) {
1386                 return (EINVAL);
1387         }
1388
1389         switch (sopt->sopt_dir) {
1390         case SOPT_SET:
1391                 switch (sopt->sopt_name) {
1392                 case IP_OPTIONS:
1393 #ifdef notyet
1394                 case IP_RETOPTS:
1395 #endif
1396                 {
1397                         struct mbuf *m;
1398                         if (sopt->sopt_valsize > MLEN) {
1399                                 error = EMSGSIZE;
1400                                 break;
1401                         }
1402                         MGET(m, sopt->sopt_td ? MB_WAIT : MB_DONTWAIT, MT_HEADER);
1403                         if (m == NULL) {
1404                                 error = ENOBUFS;
1405                                 break;
1406                         }
1407                         m->m_len = sopt->sopt_valsize;
1408                         error = sooptcopyin(sopt, mtod(m, char *), m->m_len,
1409                                             m->m_len);
1410
1411                         return (ip_pcbopts(sopt->sopt_name, &inp->inp_options,
1412                                            m));
1413                 }
1414
1415                 case IP_TOS:
1416                 case IP_TTL:
1417                 case IP_RECVOPTS:
1418                 case IP_RECVRETOPTS:
1419                 case IP_RECVDSTADDR:
1420                 case IP_RECVIF:
1421                 case IP_FAITH:
1422                         error = sooptcopyin(sopt, &optval, sizeof optval,
1423                                             sizeof optval);
1424                         if (error)
1425                                 break;
1426
1427                         switch (sopt->sopt_name) {
1428                         case IP_TOS:
1429                                 inp->inp_ip_tos = optval;
1430                                 break;
1431
1432                         case IP_TTL:
1433                                 inp->inp_ip_ttl = optval;
1434                                 break;
1435 #define OPTSET(bit) \
1436         if (optval) \
1437                 inp->inp_flags |= bit; \
1438         else \
1439                 inp->inp_flags &= ~bit;
1440
1441                         case IP_RECVOPTS:
1442                                 OPTSET(INP_RECVOPTS);
1443                                 break;
1444
1445                         case IP_RECVRETOPTS:
1446                                 OPTSET(INP_RECVRETOPTS);
1447                                 break;
1448
1449                         case IP_RECVDSTADDR:
1450                                 OPTSET(INP_RECVDSTADDR);
1451                                 break;
1452
1453                         case IP_RECVIF:
1454                                 OPTSET(INP_RECVIF);
1455                                 break;
1456
1457                         case IP_FAITH:
1458                                 OPTSET(INP_FAITH);
1459                                 break;
1460                         }
1461                         break;
1462 #undef OPTSET
1463
1464                 case IP_MULTICAST_IF:
1465                 case IP_MULTICAST_VIF:
1466                 case IP_MULTICAST_TTL:
1467                 case IP_MULTICAST_LOOP:
1468                 case IP_ADD_MEMBERSHIP:
1469                 case IP_DROP_MEMBERSHIP:
1470                         error = ip_setmoptions(sopt, &inp->inp_moptions);
1471                         break;
1472
1473                 case IP_PORTRANGE:
1474                         error = sooptcopyin(sopt, &optval, sizeof optval,
1475                                             sizeof optval);
1476                         if (error)
1477                                 break;
1478
1479                         switch (optval) {
1480                         case IP_PORTRANGE_DEFAULT:
1481                                 inp->inp_flags &= ~(INP_LOWPORT);
1482                                 inp->inp_flags &= ~(INP_HIGHPORT);
1483                                 break;
1484
1485                         case IP_PORTRANGE_HIGH:
1486                                 inp->inp_flags &= ~(INP_LOWPORT);
1487                                 inp->inp_flags |= INP_HIGHPORT;
1488                                 break;
1489
1490                         case IP_PORTRANGE_LOW:
1491                                 inp->inp_flags &= ~(INP_HIGHPORT);
1492                                 inp->inp_flags |= INP_LOWPORT;
1493                                 break;
1494
1495                         default:
1496                                 error = EINVAL;
1497                                 break;
1498                         }
1499                         break;
1500
1501 #if defined(IPSEC) || defined(FAST_IPSEC)
1502                 case IP_IPSEC_POLICY:
1503                 {
1504                         caddr_t req;
1505                         size_t len = 0;
1506                         int priv;
1507                         struct mbuf *m;
1508                         int optname;
1509
1510                         if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */
1511                                 break;
1512                         if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */
1513                                 break;
1514                         priv = (sopt->sopt_td != NULL &&
1515                                 suser(sopt->sopt_td) != 0) ? 0 : 1;
1516                         req = mtod(m, caddr_t);
1517                         len = m->m_len;
1518                         optname = sopt->sopt_name;
1519                         error = ipsec4_set_policy(inp, optname, req, len, priv);
1520                         m_freem(m);
1521                         break;
1522                 }
1523 #endif /*IPSEC*/
1524
1525                 default:
1526                         error = ENOPROTOOPT;
1527                         break;
1528                 }
1529                 break;
1530
1531         case SOPT_GET:
1532                 switch (sopt->sopt_name) {
1533                 case IP_OPTIONS:
1534                 case IP_RETOPTS:
1535                         if (inp->inp_options)
1536                                 error = sooptcopyout(sopt,
1537                                                      mtod(inp->inp_options,
1538                                                           char *),
1539                                                      inp->inp_options->m_len);
1540                         else
1541                                 sopt->sopt_valsize = 0;
1542                         break;
1543
1544                 case IP_TOS:
1545                 case IP_TTL:
1546                 case IP_RECVOPTS:
1547                 case IP_RECVRETOPTS:
1548                 case IP_RECVDSTADDR:
1549                 case IP_RECVIF:
1550                 case IP_PORTRANGE:
1551                 case IP_FAITH:
1552                         switch (sopt->sopt_name) {
1553
1554                         case IP_TOS:
1555                                 optval = inp->inp_ip_tos;
1556                                 break;
1557
1558                         case IP_TTL:
1559                                 optval = inp->inp_ip_ttl;
1560                                 break;
1561
1562 #define OPTBIT(bit)     (inp->inp_flags & bit ? 1 : 0)
1563
1564                         case IP_RECVOPTS:
1565                                 optval = OPTBIT(INP_RECVOPTS);
1566                                 break;
1567
1568                         case IP_RECVRETOPTS:
1569                                 optval = OPTBIT(INP_RECVRETOPTS);
1570                                 break;
1571
1572                         case IP_RECVDSTADDR:
1573                                 optval = OPTBIT(INP_RECVDSTADDR);
1574                                 break;
1575
1576                         case IP_RECVIF:
1577                                 optval = OPTBIT(INP_RECVIF);
1578                                 break;
1579
1580                         case IP_PORTRANGE:
1581                                 if (inp->inp_flags & INP_HIGHPORT)
1582                                         optval = IP_PORTRANGE_HIGH;
1583                                 else if (inp->inp_flags & INP_LOWPORT)
1584                                         optval = IP_PORTRANGE_LOW;
1585                                 else
1586                                         optval = 0;
1587                                 break;
1588
1589                         case IP_FAITH:
1590                                 optval = OPTBIT(INP_FAITH);
1591                                 break;
1592                         }
1593                         error = sooptcopyout(sopt, &optval, sizeof optval);
1594                         break;
1595
1596                 case IP_MULTICAST_IF:
1597                 case IP_MULTICAST_VIF:
1598                 case IP_MULTICAST_TTL:
1599                 case IP_MULTICAST_LOOP:
1600                 case IP_ADD_MEMBERSHIP:
1601                 case IP_DROP_MEMBERSHIP:
1602                         error = ip_getmoptions(sopt, inp->inp_moptions);
1603                         break;
1604
1605 #if defined(IPSEC) || defined(FAST_IPSEC)
1606                 case IP_IPSEC_POLICY:
1607                 {
1608                         struct mbuf *m = NULL;
1609                         caddr_t req = NULL;
1610                         size_t len = 0;
1611
1612                         if (m != NULL) {
1613                                 req = mtod(m, caddr_t);
1614                                 len = m->m_len;
1615                         }
1616                         error = ipsec4_get_policy(so->so_pcb, req, len, &m);
1617                         if (error == 0)
1618                                 error = soopt_mcopyout(sopt, m); /* XXX */
1619                         if (error == 0)
1620                                 m_freem(m);
1621                         break;
1622                 }
1623 #endif /*IPSEC*/
1624
1625                 default:
1626                         error = ENOPROTOOPT;
1627                         break;
1628                 }
1629                 break;
1630         }
1631         return (error);
1632 }
1633
1634 /*
1635  * Set up IP options in pcb for insertion in output packets.
1636  * Store in mbuf with pointer in pcbopt, adding pseudo-option
1637  * with destination address if source routed.
1638  */
1639 static int
1640 ip_pcbopts(int optname, struct mbuf **pcbopt, struct mbuf *m)
1641 {
1642         int cnt, optlen;
1643         u_char *cp;
1644         u_char opt;
1645
1646         /* turn off any old options */
1647         if (*pcbopt)
1648                 m_free(*pcbopt);
1649         *pcbopt = 0;
1650         if (m == NULL || m->m_len == 0) {
1651                 /*
1652                  * Only turning off any previous options.
1653                  */
1654                 if (m != NULL)
1655                         m_free(m);
1656                 return (0);
1657         }
1658
1659         if (m->m_len % sizeof(int32_t))
1660                 goto bad;
1661         /*
1662          * IP first-hop destination address will be stored before
1663          * actual options; move other options back
1664          * and clear it when none present.
1665          */
1666         if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN])
1667                 goto bad;
1668         cnt = m->m_len;
1669         m->m_len += sizeof(struct in_addr);
1670         cp = mtod(m, u_char *) + sizeof(struct in_addr);
1671         ovbcopy(mtod(m, caddr_t), cp, cnt);
1672         bzero(mtod(m, caddr_t), sizeof(struct in_addr));
1673
1674         for (; cnt > 0; cnt -= optlen, cp += optlen) {
1675                 opt = cp[IPOPT_OPTVAL];
1676                 if (opt == IPOPT_EOL)
1677                         break;
1678                 if (opt == IPOPT_NOP)
1679                         optlen = 1;
1680                 else {
1681                         if (cnt < IPOPT_OLEN + sizeof *cp)
1682                                 goto bad;
1683                         optlen = cp[IPOPT_OLEN];
1684                         if (optlen < IPOPT_OLEN + sizeof *cp || optlen > cnt)
1685                                 goto bad;
1686                 }
1687                 switch (opt) {
1688
1689                 default:
1690                         break;
1691
1692                 case IPOPT_LSRR:
1693                 case IPOPT_SSRR:
1694                         /*
1695                          * user process specifies route as:
1696                          *      ->A->B->C->D
1697                          * D must be our final destination (but we can't
1698                          * check that since we may not have connected yet).
1699                          * A is first hop destination, which doesn't appear in
1700                          * actual IP option, but is stored before the options.
1701                          */
1702                         if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr))
1703                                 goto bad;
1704                         m->m_len -= sizeof(struct in_addr);
1705                         cnt -= sizeof(struct in_addr);
1706                         optlen -= sizeof(struct in_addr);
1707                         cp[IPOPT_OLEN] = optlen;
1708                         /*
1709                          * Move first hop before start of options.
1710                          */
1711                         bcopy(&cp[IPOPT_OFFSET+1], mtod(m, caddr_t),
1712                               sizeof(struct in_addr));
1713                         /*
1714                          * Then copy rest of options back
1715                          * to close up the deleted entry.
1716                          */
1717                         ovbcopy(&cp[IPOPT_OFFSET+1] + sizeof(struct in_addr),
1718                                 &cp[IPOPT_OFFSET+1],
1719                                 cnt - (IPOPT_MINOFF - 1));
1720                         break;
1721                 }
1722         }
1723         if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr))
1724                 goto bad;
1725         *pcbopt = m;
1726         return (0);
1727
1728 bad:
1729         m_free(m);
1730         return (EINVAL);
1731 }
1732
1733 /*
1734  * XXX
1735  * The whole multicast option thing needs to be re-thought.
1736  * Several of these options are equally applicable to non-multicast
1737  * transmission, and one (IP_MULTICAST_TTL) totally duplicates a
1738  * standard option (IP_TTL).
1739  */
1740
1741 /*
1742  * following RFC1724 section 3.3, 0.0.0.0/8 is interpreted as interface index.
1743  */
1744 static struct ifnet *
1745 ip_multicast_if(struct in_addr *a, int *ifindexp)
1746 {
1747         int ifindex;
1748         struct ifnet *ifp;
1749
1750         if (ifindexp)
1751                 *ifindexp = 0;
1752         if (ntohl(a->s_addr) >> 24 == 0) {
1753                 ifindex = ntohl(a->s_addr) & 0xffffff;
1754                 if (ifindex < 0 || if_index < ifindex)
1755                         return NULL;
1756                 ifp = ifindex2ifnet[ifindex];
1757                 if (ifindexp)
1758                         *ifindexp = ifindex;
1759         } else {
1760                 INADDR_TO_IFP(*a, ifp);
1761         }
1762         return ifp;
1763 }
1764
1765 /*
1766  * Set the IP multicast options in response to user setsockopt().
1767  */
1768 static int
1769 ip_setmoptions(struct sockopt *sopt, struct ip_moptions **imop)
1770 {
1771         int error = 0;
1772         int i;
1773         struct in_addr addr;
1774         struct ip_mreq mreq;
1775         struct ifnet *ifp;
1776         struct ip_moptions *imo = *imop;
1777         struct sockaddr_in *dst;
1778         int ifindex;
1779         int s;
1780
1781         if (imo == NULL) {
1782                 /*
1783                  * No multicast option buffer attached to the pcb;
1784                  * allocate one and initialize to default values.
1785                  */
1786                 imo = malloc(sizeof *imo, M_IPMOPTS, M_WAITOK);
1787
1788                 if (imo == NULL)
1789                         return (ENOBUFS);
1790                 *imop = imo;
1791                 imo->imo_multicast_ifp = NULL;
1792                 imo->imo_multicast_addr.s_addr = INADDR_ANY;
1793                 imo->imo_multicast_vif = -1;
1794                 imo->imo_multicast_ttl = IP_DEFAULT_MULTICAST_TTL;
1795                 imo->imo_multicast_loop = IP_DEFAULT_MULTICAST_LOOP;
1796                 imo->imo_num_memberships = 0;
1797         }
1798
1799         switch (sopt->sopt_name) {
1800         /* store an index number for the vif you wanna use in the send */
1801         case IP_MULTICAST_VIF:
1802                 if (legal_vif_num == 0) {
1803                         error = EOPNOTSUPP;
1804                         break;
1805                 }
1806                 error = sooptcopyin(sopt, &i, sizeof i, sizeof i);
1807                 if (error)
1808                         break;
1809                 if (!legal_vif_num(i) && (i != -1)) {
1810                         error = EINVAL;
1811                         break;
1812                 }
1813                 imo->imo_multicast_vif = i;
1814                 break;
1815
1816         case IP_MULTICAST_IF:
1817                 /*
1818                  * Select the interface for outgoing multicast packets.
1819                  */
1820                 error = sooptcopyin(sopt, &addr, sizeof addr, sizeof addr);
1821                 if (error)
1822                         break;
1823                 /*
1824                  * INADDR_ANY is used to remove a previous selection.
1825                  * When no interface is selected, a default one is
1826                  * chosen every time a multicast packet is sent.
1827                  */
1828                 if (addr.s_addr == INADDR_ANY) {
1829                         imo->imo_multicast_ifp = NULL;
1830                         break;
1831                 }
1832                 /*
1833                  * The selected interface is identified by its local
1834                  * IP address.  Find the interface and confirm that
1835                  * it supports multicasting.
1836                  */
1837                 s = splimp();
1838                 ifp = ip_multicast_if(&addr, &ifindex);
1839                 if (ifp == NULL || !(ifp->if_flags & IFF_MULTICAST)) {
1840                         splx(s);
1841                         error = EADDRNOTAVAIL;
1842                         break;
1843                 }
1844                 imo->imo_multicast_ifp = ifp;
1845                 if (ifindex)
1846                         imo->imo_multicast_addr = addr;
1847                 else
1848                         imo->imo_multicast_addr.s_addr = INADDR_ANY;
1849                 splx(s);
1850                 break;
1851
1852         case IP_MULTICAST_TTL:
1853                 /*
1854                  * Set the IP time-to-live for outgoing multicast packets.
1855                  * The original multicast API required a char argument,
1856                  * which is inconsistent with the rest of the socket API.
1857                  * We allow either a char or an int.
1858                  */
1859                 if (sopt->sopt_valsize == 1) {
1860                         u_char ttl;
1861                         error = sooptcopyin(sopt, &ttl, 1, 1);
1862                         if (error)
1863                                 break;
1864                         imo->imo_multicast_ttl = ttl;
1865                 } else {
1866                         u_int ttl;
1867                         error = sooptcopyin(sopt, &ttl, sizeof ttl, sizeof ttl);
1868                         if (error)
1869                                 break;
1870                         if (ttl > 255)
1871                                 error = EINVAL;
1872                         else
1873                                 imo->imo_multicast_ttl = ttl;
1874                 }
1875                 break;
1876
1877         case IP_MULTICAST_LOOP:
1878                 /*
1879                  * Set the loopback flag for outgoing multicast packets.
1880                  * Must be zero or one.  The original multicast API required a
1881                  * char argument, which is inconsistent with the rest
1882                  * of the socket API.  We allow either a char or an int.
1883                  */
1884                 if (sopt->sopt_valsize == 1) {
1885                         u_char loop;
1886
1887                         error = sooptcopyin(sopt, &loop, 1, 1);
1888                         if (error)
1889                                 break;
1890                         imo->imo_multicast_loop = !!loop;
1891                 } else {
1892                         u_int loop;
1893
1894                         error = sooptcopyin(sopt, &loop, sizeof loop,
1895                                             sizeof loop);
1896                         if (error)
1897                                 break;
1898                         imo->imo_multicast_loop = !!loop;
1899                 }
1900                 break;
1901
1902         case IP_ADD_MEMBERSHIP:
1903                 /*
1904                  * Add a multicast group membership.
1905                  * Group must be a valid IP multicast address.
1906                  */
1907                 error = sooptcopyin(sopt, &mreq, sizeof mreq, sizeof mreq);
1908                 if (error)
1909                         break;
1910
1911                 if (!IN_MULTICAST(ntohl(mreq.imr_multiaddr.s_addr))) {
1912                         error = EINVAL;
1913                         break;
1914                 }
1915                 s = splimp();
1916                 /*
1917                  * If no interface address was provided, use the interface of
1918                  * the route to the given multicast address.
1919                  */
1920                 if (mreq.imr_interface.s_addr == INADDR_ANY) {
1921                         struct route ro;
1922
1923                         bzero(&ro, sizeof ro);
1924                         dst = (struct sockaddr_in *)&ro.ro_dst;
1925                         dst->sin_len = sizeof *dst;
1926                         dst->sin_family = AF_INET;
1927                         dst->sin_addr = mreq.imr_multiaddr;
1928                         rtalloc(&ro);
1929                         if (ro.ro_rt == NULL) {
1930                                 error = EADDRNOTAVAIL;
1931                                 splx(s);
1932                                 break;
1933                         }
1934                         --ro.ro_rt->rt_refcnt;
1935                         ifp = ro.ro_rt->rt_ifp;
1936                 }
1937                 else {
1938                         ifp = ip_multicast_if(&mreq.imr_interface, NULL);
1939                 }
1940
1941                 /*
1942                  * See if we found an interface, and confirm that it
1943                  * supports multicast.
1944                  */
1945                 if (ifp == NULL || !(ifp->if_flags & IFF_MULTICAST)) {
1946                         error = EADDRNOTAVAIL;
1947                         splx(s);
1948                         break;
1949                 }
1950                 /*
1951                  * See if the membership already exists or if all the
1952                  * membership slots are full.
1953                  */
1954                 for (i = 0; i < imo->imo_num_memberships; ++i) {
1955                         if (imo->imo_membership[i]->inm_ifp == ifp &&
1956                             imo->imo_membership[i]->inm_addr.s_addr
1957                                                 == mreq.imr_multiaddr.s_addr)
1958                                 break;
1959                 }
1960                 if (i < imo->imo_num_memberships) {
1961                         error = EADDRINUSE;
1962                         splx(s);
1963                         break;
1964                 }
1965                 if (i == IP_MAX_MEMBERSHIPS) {
1966                         error = ETOOMANYREFS;
1967                         splx(s);
1968                         break;
1969                 }
1970                 /*
1971                  * Everything looks good; add a new record to the multicast
1972                  * address list for the given interface.
1973                  */
1974                 if ((imo->imo_membership[i] =
1975                      in_addmulti(&mreq.imr_multiaddr, ifp)) == NULL) {
1976                         error = ENOBUFS;
1977                         splx(s);
1978                         break;
1979                 }
1980                 ++imo->imo_num_memberships;
1981                 splx(s);
1982                 break;
1983
1984         case IP_DROP_MEMBERSHIP:
1985                 /*
1986                  * Drop a multicast group membership.
1987                  * Group must be a valid IP multicast address.
1988                  */
1989                 error = sooptcopyin(sopt, &mreq, sizeof mreq, sizeof mreq);
1990                 if (error)
1991                         break;
1992
1993                 if (!IN_MULTICAST(ntohl(mreq.imr_multiaddr.s_addr))) {
1994                         error = EINVAL;
1995                         break;
1996                 }
1997
1998                 s = splimp();
1999                 /*
2000                  * If an interface address was specified, get a pointer
2001                  * to its ifnet structure.
2002                  */
2003                 if (mreq.imr_interface.s_addr == INADDR_ANY)
2004                         ifp = NULL;
2005                 else {
2006                         ifp = ip_multicast_if(&mreq.imr_interface, NULL);
2007                         if (ifp == NULL) {
2008                                 error = EADDRNOTAVAIL;
2009                                 splx(s);
2010                                 break;
2011                         }
2012                 }
2013                 /*
2014                  * Find the membership in the membership array.
2015                  */
2016                 for (i = 0; i < imo->imo_num_memberships; ++i) {
2017                         if ((ifp == NULL ||
2018                              imo->imo_membership[i]->inm_ifp == ifp) &&
2019                             imo->imo_membership[i]->inm_addr.s_addr ==
2020                             mreq.imr_multiaddr.s_addr)
2021                                 break;
2022                 }
2023                 if (i == imo->imo_num_memberships) {
2024                         error = EADDRNOTAVAIL;
2025                         splx(s);
2026                         break;
2027                 }
2028                 /*
2029                  * Give up the multicast address record to which the
2030                  * membership points.
2031                  */
2032                 in_delmulti(imo->imo_membership[i]);
2033                 /*
2034                  * Remove the gap in the membership array.
2035                  */
2036                 for (++i; i < imo->imo_num_memberships; ++i)
2037                         imo->imo_membership[i-1] = imo->imo_membership[i];
2038                 --imo->imo_num_memberships;
2039                 splx(s);
2040                 break;
2041
2042         default:
2043                 error = EOPNOTSUPP;
2044                 break;
2045         }
2046
2047         /*
2048          * If all options have default values, no need to keep the mbuf.
2049          */
2050         if (imo->imo_multicast_ifp == NULL &&
2051             imo->imo_multicast_vif == -1 &&
2052             imo->imo_multicast_ttl == IP_DEFAULT_MULTICAST_TTL &&
2053             imo->imo_multicast_loop == IP_DEFAULT_MULTICAST_LOOP &&
2054             imo->imo_num_memberships == 0) {
2055                 free(*imop, M_IPMOPTS);
2056                 *imop = NULL;
2057         }
2058
2059         return (error);
2060 }
2061
2062 /*
2063  * Return the IP multicast options in response to user getsockopt().
2064  */
2065 static int
2066 ip_getmoptions(struct sockopt *sopt, struct ip_moptions *imo)
2067 {
2068         struct in_addr addr;
2069         struct in_ifaddr *ia;
2070         int error, optval;
2071         u_char coptval;
2072
2073         error = 0;
2074         switch (sopt->sopt_name) {
2075         case IP_MULTICAST_VIF:
2076                 if (imo != NULL)
2077                         optval = imo->imo_multicast_vif;
2078                 else
2079                         optval = -1;
2080                 error = sooptcopyout(sopt, &optval, sizeof optval);
2081                 break;
2082
2083         case IP_MULTICAST_IF:
2084                 if (imo == NULL || imo->imo_multicast_ifp == NULL)
2085                         addr.s_addr = INADDR_ANY;
2086                 else if (imo->imo_multicast_addr.s_addr) {
2087                         /* return the value user has set */
2088                         addr = imo->imo_multicast_addr;
2089                 } else {
2090                         IFP_TO_IA(imo->imo_multicast_ifp, ia);
2091                         addr.s_addr = (ia == NULL) ? INADDR_ANY
2092                                 : IA_SIN(ia)->sin_addr.s_addr;
2093                 }
2094                 error = sooptcopyout(sopt, &addr, sizeof addr);
2095                 break;
2096
2097         case IP_MULTICAST_TTL:
2098                 if (imo == NULL)
2099                         optval = coptval = IP_DEFAULT_MULTICAST_TTL;
2100                 else
2101                         optval = coptval = imo->imo_multicast_ttl;
2102                 if (sopt->sopt_valsize == 1)
2103                         error = sooptcopyout(sopt, &coptval, 1);
2104                 else
2105                         error = sooptcopyout(sopt, &optval, sizeof optval);
2106                 break;
2107
2108         case IP_MULTICAST_LOOP:
2109                 if (imo == NULL)
2110                         optval = coptval = IP_DEFAULT_MULTICAST_LOOP;
2111                 else
2112                         optval = coptval = imo->imo_multicast_loop;
2113                 if (sopt->sopt_valsize == 1)
2114                         error = sooptcopyout(sopt, &coptval, 1);
2115                 else
2116                         error = sooptcopyout(sopt, &optval, sizeof optval);
2117                 break;
2118
2119         default:
2120                 error = ENOPROTOOPT;
2121                 break;
2122         }
2123         return (error);
2124 }
2125
2126 /*
2127  * Discard the IP multicast options.
2128  */
2129 void
2130 ip_freemoptions(struct ip_moptions *imo)
2131 {
2132         int i;
2133
2134         if (imo != NULL) {
2135                 for (i = 0; i < imo->imo_num_memberships; ++i)
2136                         in_delmulti(imo->imo_membership[i]);
2137                 free(imo, M_IPMOPTS);
2138         }
2139 }
2140
2141 /*
2142  * Routine called from ip_output() to loop back a copy of an IP multicast
2143  * packet to the input queue of a specified interface.  Note that this
2144  * calls the output routine of the loopback "driver", but with an interface
2145  * pointer that might NOT be a loopback interface -- evil, but easier than
2146  * replicating that code here.
2147  */
2148 static void
2149 ip_mloopback(struct ifnet *ifp, struct mbuf *m, struct sockaddr_in *dst,
2150              int hlen)
2151 {
2152         struct ip *ip;
2153         struct mbuf *copym;
2154
2155         copym = m_copypacket(m, MB_DONTWAIT);
2156         if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen))
2157                 copym = m_pullup(copym, hlen);
2158         if (copym != NULL) {
2159                 /*
2160                  * if the checksum hasn't been computed, mark it as valid
2161                  */
2162                 if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
2163                         in_delayed_cksum(copym);
2164                         copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
2165                         copym->m_pkthdr.csum_flags |=
2166                             CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
2167                         copym->m_pkthdr.csum_data = 0xffff;
2168                 }
2169                 /*
2170                  * We don't bother to fragment if the IP length is greater
2171                  * than the interface's MTU.  Can this possibly matter?
2172                  */
2173                 ip = mtod(copym, struct ip *);
2174                 ip->ip_len = htons(ip->ip_len);
2175                 ip->ip_off = htons(ip->ip_off);
2176                 ip->ip_sum = 0;
2177                 if (ip->ip_vhl == IP_VHL_BORING) {
2178                         ip->ip_sum = in_cksum_hdr(ip);
2179                 } else {
2180                         ip->ip_sum = in_cksum(copym, hlen);
2181                 }
2182                 /*
2183                  * NB:
2184                  * It's not clear whether there are any lingering
2185                  * reentrancy problems in other areas which might
2186                  * be exposed by using ip_input directly (in
2187                  * particular, everything which modifies the packet
2188                  * in-place).  Yet another option is using the
2189                  * protosw directly to deliver the looped back
2190                  * packet.  For the moment, we'll err on the side
2191                  * of safety by using if_simloop().
2192                  */
2193 #if 1 /* XXX */
2194                 if (dst->sin_family != AF_INET) {
2195                         printf("ip_mloopback: bad address family %d\n",
2196                                                 dst->sin_family);
2197                         dst->sin_family = AF_INET;
2198                 }
2199 #endif
2200
2201 #ifdef notdef
2202                 copym->m_pkthdr.rcvif = ifp;
2203                 ip_input(copym);
2204 #else
2205                 if_simloop(ifp, copym, dst->sin_family, 0);
2206 #endif
2207         }
2208 }