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 1.28 2005/04/18 14:26:57 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
 155         /* Grab info from MT_TAG mbufs prepended to the chain. */
 156         while (m0 != NULL && m0->m_type == MT_TAG) {
 157                 switch(m0->_m_tag_id) {
 158                 case PACKET_TAG_DUMMYNET:
 159                         /*
 160                          * the packet was already tagged, so part of the
 161                          * processing was already done, and we need to go down.
 162                          * Get parameters from the header.
 163                          */
 164                         args.rule = ((struct dn_pkt *)m0)->rule;
 165                         opt = NULL ;
 166                         ro = &((struct dn_pkt *)m0)->ro;
 167                         imo = NULL ;
 168                         dst = ((struct dn_pkt *)m0)->dn_dst ;
 169                         ifp = ((struct dn_pkt *)m0)->ifp ;
 170                         flags = ((struct dn_pkt *)m0)->flags ;
 171                         break;
 172                 case PACKET_TAG_IPFORWARD:
 173                         args.next_hop = (struct sockaddr_in *)m0->m_data;
 174                         break;
 175                 default:
 176                         printf("ip_output: unrecognised MT_TAG tag %d\n",
 177                             m0->_m_tag_id);
 178                         break;
 179                 }
 180                 m0 = m0->m_next;
 181         }
 182         m = m0;
 183         KASSERT(m != NULL && (m->m_flags & M_PKTHDR), ("ip_output: no HDR"));
 184
 185         if (ro == NULL) {
 186                 ro = &iproute;
 187                 bzero(ro, sizeof *ro);
 188         }
 189
 190         if (args.rule != NULL) {        /* dummynet already saw us */
 191                 ip = mtod(m, struct ip *);
 192                 hlen = IP_VHL_HL(ip->ip_vhl) << 2 ;
 193                 if (ro->ro_rt)
 194                         ia = ifatoia(ro->ro_rt->rt_ifa);
 195                 goto sendit;
 196         }
 197
 198         if (opt) {
 199                 len = 0;
 200                 m = ip_insertoptions(m, opt, &len);
 201                 if (len != 0)
 202                         hlen = len;
 203         }
 204         ip = mtod(m, struct ip *);
 205         pkt_dst = args.next_hop ? args.next_hop->sin_addr : ip->ip_dst;
 206
 207         /*
 208          * Fill in IP header.
 209          */
 210         if (!(flags & (IP_FORWARDING|IP_RAWOUTPUT))) {
 211                 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, hlen >> 2);
 212                 ip->ip_off &= IP_DF;
 213 #ifdef RANDOM_IP_ID
 214                 ip->ip_id = ip_randomid();
 215 #else
 216                 ip->ip_id = htons(ip_id++);
 217 #endif
 218                 ipstat.ips_localout++;
 219         } else {
 220                 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 221         }
 222
 223         dst = (struct sockaddr_in *)&ro->ro_dst;
 224         /*
 225          * If there is a cached route,
 226          * check that it is to the same destination
 227          * and is still up.  If not, free it and try again.
 228          * The address family should also be checked in case of sharing the
 229          * cache with IPv6.
 230          */
 231         if (ro->ro_rt &&
 232             (!(ro->ro_rt->rt_flags & RTF_UP) ||
 233              dst->sin_family != AF_INET ||
 234              dst->sin_addr.s_addr != pkt_dst.s_addr)) {
 235                 rtfree(ro->ro_rt);
 236                 ro->ro_rt = (struct rtentry *)NULL;
 237         }
 238         if (ro->ro_rt == NULL) {
 239                 bzero(dst, sizeof *dst);
 240                 dst->sin_family = AF_INET;
 241                 dst->sin_len = sizeof *dst;
 242                 dst->sin_addr = pkt_dst;
 243         }
 244         /*
 245          * If routing to interface only,
 246          * short circuit routing lookup.
 247          */
 248         if (flags & IP_ROUTETOIF) {
 249                 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL &&
 250                     (ia = ifatoia(ifa_ifwithnet(sintosa(dst)))) == NULL) {
 251                         ipstat.ips_noroute++;
 252                         error = ENETUNREACH;
 253                         goto bad;
 254                 }
 255                 ifp = ia->ia_ifp;
 256                 ip->ip_ttl = 1;
 257                 isbroadcast = in_broadcast(dst->sin_addr, ifp);
 258         } else if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) &&
 259                    imo != NULL && imo->imo_multicast_ifp != NULL) {
 260                 /*
 261                  * Bypass the normal routing lookup for multicast
 262                  * packets if the interface is specified.
 263                  */
 264                 ifp = imo->imo_multicast_ifp;
 265                 IFP_TO_IA(ifp, ia);
 266                 isbroadcast = 0;        /* fool gcc */
 267         } else {
 268                 /*
 269                  * If this is the case, we probably don't want to allocate
 270                  * a protocol-cloned route since we didn't get one from the
 271                  * ULP.  This lets TCP do its thing, while not burdening
 272                  * forwarding or ICMP with the overhead of cloning a route.
 273                  * Of course, we still want to do any cloning requested by
 274                  * the link layer, as this is probably required in all cases
 275                  * for correct operation (as it is for ARP).
 276                  */
 277                 if (ro->ro_rt == NULL)
 278                         rtalloc_ign(ro, RTF_PRCLONING);
 279                 if (ro->ro_rt == NULL) {
 280                         ipstat.ips_noroute++;
 281                         error = EHOSTUNREACH;
 282                         goto bad;
 283                 }
 284                 ia = ifatoia(ro->ro_rt->rt_ifa);
 285                 ifp = ro->ro_rt->rt_ifp;
 286                 ro->ro_rt->rt_use++;
 287                 if (ro->ro_rt->rt_flags & RTF_GATEWAY)
 288                         dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway;
 289                 if (ro->ro_rt->rt_flags & RTF_HOST)
 290                         isbroadcast = (ro->ro_rt->rt_flags & RTF_BROADCAST);
 291                 else
 292                         isbroadcast = in_broadcast(dst->sin_addr, ifp);
 293         }
 294         if (IN_MULTICAST(ntohl(pkt_dst.s_addr))) {
 295                 struct in_multi *inm;
 296
 297                 m->m_flags |= M_MCAST;
 298                 /*
 299                  * IP destination address is multicast.  Make sure "dst"
 300                  * still points to the address in "ro".  (It may have been
 301                  * changed to point to a gateway address, above.)
 302                  */
 303                 dst = (struct sockaddr_in *)&ro->ro_dst;
 304                 /*
 305                  * See if the caller provided any multicast options
 306                  */
 307                 if (imo != NULL) {
 308                         ip->ip_ttl = imo->imo_multicast_ttl;
 309                         if (imo->imo_multicast_vif != -1)
 310                                 ip->ip_src.s_addr =
 311                                     ip_mcast_src ?
 312                                     ip_mcast_src(imo->imo_multicast_vif) :
 313                                     INADDR_ANY;
 314                 } else
 315                         ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL;
 316                 /*
 317                  * Confirm that the outgoing interface supports multicast.
 318                  */
 319                 if ((imo == NULL) || (imo->imo_multicast_vif == -1)) {
 320                         if (!(ifp->if_flags & IFF_MULTICAST)) {
 321                                 ipstat.ips_noroute++;
 322                                 error = ENETUNREACH;
 323                                 goto bad;
 324                         }
 325                 }
 326                 /*
 327                  * If source address not specified yet, use address
 328                  * of outgoing interface.
 329                  */
 330                 if (ip->ip_src.s_addr == INADDR_ANY) {
 331                         /* Interface may have no addresses. */
 332                         if (ia != NULL)
 333                                 ip->ip_src = IA_SIN(ia)->sin_addr;
 334                 }
 335
 336                 IN_LOOKUP_MULTI(pkt_dst, ifp, inm);
 337                 if (inm != NULL &&
 338                    (imo == NULL || imo->imo_multicast_loop)) {
 339                         /*
 340                          * If we belong to the destination multicast group
 341                          * on the outgoing interface, and the caller did not
 342                          * forbid loopback, loop back a copy.
 343                          */
 344                         ip_mloopback(ifp, m, dst, hlen);
 345                 }
 346                 else {
 347                         /*
 348                          * If we are acting as a multicast router, perform
 349                          * multicast forwarding as if the packet had just
 350                          * arrived on the interface to which we are about
 351                          * to send.  The multicast forwarding function
 352                          * recursively calls this function, using the
 353                          * IP_FORWARDING flag to prevent infinite recursion.
 354                          *
 355                          * Multicasts that are looped back by ip_mloopback(),
 356                          * above, will be forwarded by the ip_input() routine,
 357                          * if necessary.
 358                          */
 359                         if (ip_mrouter && !(flags & IP_FORWARDING)) {
 360                                 /*
 361                                  * If rsvp daemon is not running, do not
 362                                  * set ip_moptions. This ensures that the packet
 363                                  * is multicast and not just sent down one link
 364                                  * as prescribed by rsvpd.
 365                                  */
 366                                 if (!rsvp_on)
 367                                         imo = NULL;
 368                                 if (ip_mforward &&
 369                                     ip_mforward(ip, ifp, m, imo) != 0) {
 370                                         m_freem(m);
 371                                         goto done;
 372                                 }
 373                         }
 374                 }
 375
 376                 /*
 377                  * Multicasts with a time-to-live of zero may be looped-
 378                  * back, above, but must not be transmitted on a network.
 379                  * Also, multicasts addressed to the loopback interface
 380                  * are not sent -- the above call to ip_mloopback() will
 381                  * loop back a copy if this host actually belongs to the
 382                  * destination group on the loopback interface.
 383                  */
 384                 if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) {
 385                         m_freem(m);
 386                         goto done;
 387                 }
 388
 389                 goto sendit;
 390         }
 391 #ifndef notdef
 392         /*
 393          * If the source address is not specified yet, use the address
 394          * of the outoing interface. In case, keep note we did that, so
 395          * if the the firewall changes the next-hop causing the output
 396          * interface to change, we can fix that.
 397          */
 398         if (ip->ip_src.s_addr == INADDR_ANY) {
 399                 /* Interface may have no addresses. */
 400                 if (ia != NULL) {
 401                         ip->ip_src = IA_SIN(ia)->sin_addr;
 402                         src_was_INADDR_ANY = 1;
 403                 }
 404         }
 405 #endif /* notdef */
 406 #ifdef ALTQ
 407         /*
 408          * Disable packet drop hack.
 409          * Packetdrop should be done by queueing.
 410          */
 411 #else /* !ALTQ */
 412         /*
 413          * Verify that we have any chance at all of being able to queue
 414          *      the packet or packet fragments
 415          */
 416         if ((ifp->if_snd.ifq_len + ip->ip_len / ifp->if_mtu + 1) >=
 417                 ifp->if_snd.ifq_maxlen) {
 418                         error = ENOBUFS;
 419                         ipstat.ips_odropped++;
 420                         goto bad;
 421         }
 422 #endif /* !ALTQ */
 423
 424         /*
 425          * Look for broadcast address and
 426          * verify user is allowed to send
 427          * such a packet.
 428          */
 429         if (isbroadcast) {
 430                 if (!(ifp->if_flags & IFF_BROADCAST)) {
 431                         error = EADDRNOTAVAIL;
 432                         goto bad;
 433                 }
 434                 if (!(flags & IP_ALLOWBROADCAST)) {
 435                         error = EACCES;
 436                         goto bad;
 437                 }
 438                 /* don't allow broadcast messages to be fragmented */
 439                 if (ip->ip_len > ifp->if_mtu) {
 440                         error = EMSGSIZE;
 441                         goto bad;
 442                 }
 443                 m->m_flags |= M_BCAST;
 444         } else {
 445                 m->m_flags &= ~M_BCAST;
 446         }
 447
 448 sendit:
 449 #ifdef IPSEC
 450         /* get SP for this packet */
 451         if (so == NULL)
 452                 sp = ipsec4_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, flags, &error);
 453         else
 454                 sp = ipsec4_getpolicybysock(m, IPSEC_DIR_OUTBOUND, so, &error);
 455
 456         if (sp == NULL) {
 457                 ipsecstat.out_inval++;
 458                 goto bad;
 459         }
 460
 461         error = 0;
 462
 463         /* check policy */
 464         switch (sp->policy) {
 465         case IPSEC_POLICY_DISCARD:
 466                 /*
 467                  * This packet is just discarded.
 468                  */
 469                 ipsecstat.out_polvio++;
 470                 goto bad;
 471
 472         case IPSEC_POLICY_BYPASS:
 473         case IPSEC_POLICY_NONE:
 474                 /* no need to do IPsec. */
 475                 goto skip_ipsec;
 476
 477         case IPSEC_POLICY_IPSEC:
 478                 if (sp->req == NULL) {
 479                         /* acquire a policy */
 480                         error = key_spdacquire(sp);
 481                         goto bad;
 482                 }
 483                 break;
 484
 485         case IPSEC_POLICY_ENTRUST:
 486         default:
 487                 printf("ip_output: Invalid policy found. %d\n", sp->policy);
 488         }
 489     {
 490         struct ipsec_output_state state;
 491         bzero(&state, sizeof state);
 492         state.m = m;
 493         if (flags & IP_ROUTETOIF) {
 494                 state.ro = &iproute;
 495                 bzero(&iproute, sizeof iproute);
 496         } else
 497                 state.ro = ro;
 498         state.dst = (struct sockaddr *)dst;
 499
 500         ip->ip_sum = 0;
 501
 502         /*
 503          * XXX
 504          * delayed checksums are not currently compatible with IPsec
 505          */
 506         if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 507                 in_delayed_cksum(m);
 508                 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
 509         }
 510
 511         ip->ip_len = htons(ip->ip_len);
 512         ip->ip_off = htons(ip->ip_off);
 513
 514         error = ipsec4_output(&state, sp, flags);
 515
 516         m = state.m;
 517         if (flags & IP_ROUTETOIF) {
 518                 /*
 519                  * if we have tunnel mode SA, we may need to ignore
 520                  * IP_ROUTETOIF.
 521                  */
 522                 if (state.ro != &iproute || state.ro->ro_rt != NULL) {
 523                         flags &= ~IP_ROUTETOIF;
 524                         ro = state.ro;
 525                 }
 526         } else
 527                 ro = state.ro;
 528         dst = (struct sockaddr_in *)state.dst;
 529         if (error) {
 530                 /* mbuf is already reclaimed in ipsec4_output. */
 531                 m0 = NULL;
 532                 switch (error) {
 533                 case EHOSTUNREACH:
 534                 case ENETUNREACH:
 535                 case EMSGSIZE:
 536                 case ENOBUFS:
 537                 case ENOMEM:
 538                         break;
 539                 default:
 540                         printf("ip4_output (ipsec): error code %d\n", error);
 541                         /*fall through*/
 542                 case ENOENT:
 543                         /* don't show these error codes to the user */
 544                         error = 0;
 545                         break;
 546                 }
 547                 goto bad;
 548         }
 549     }
 550
 551         /* be sure to update variables that are affected by ipsec4_output() */
 552         ip = mtod(m, struct ip *);
 553 #ifdef _IP_VHL
 554         hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 555 #else
 556         hlen = ip->ip_hl << 2;
 557 #endif
 558         if (ro->ro_rt == NULL) {
 559                 if (!(flags & IP_ROUTETOIF)) {
 560                         printf("ip_output: "
 561                                 "can't update route after IPsec processing\n");
 562                         error = EHOSTUNREACH;   /*XXX*/
 563                         goto bad;
 564                 }
 565         } else {
 566                 ia = ifatoia(ro->ro_rt->rt_ifa);
 567                 ifp = ro->ro_rt->rt_ifp;
 568         }
 569
 570         /* make it flipped, again. */
 571         ip->ip_len = ntohs(ip->ip_len);
 572         ip->ip_off = ntohs(ip->ip_off);
 573 skip_ipsec:
 574 #endif /*IPSEC*/
 575 #ifdef FAST_IPSEC
 576         /*
 577          * Check the security policy (SP) for the packet and, if
 578          * required, do IPsec-related processing.  There are two
 579          * cases here; the first time a packet is sent through
 580          * it will be untagged and handled by ipsec4_checkpolicy.
 581          * If the packet is resubmitted to ip_output (e.g. after
 582          * AH, ESP, etc. processing), there will be a tag to bypass
 583          * the lookup and related policy checking.
 584          */
 585         mtag = m_tag_find(m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
 586         s = splnet();
 587         if (mtag != NULL) {
 588                 tdbi = (struct tdb_ident *)(mtag + 1);
 589                 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
 590                 if (sp == NULL)
 591                         error = -EINVAL;        /* force silent drop */
 592                 m_tag_delete(m, mtag);
 593         } else {
 594                 sp = ipsec4_checkpolicy(m, IPSEC_DIR_OUTBOUND, flags,
 595                                         &error, inp);
 596         }
 597         /*
 598          * There are four return cases:
 599          *    sp != NULL                    apply IPsec policy
 600          *    sp == NULL, error == 0        no IPsec handling needed
 601          *    sp == NULL, error == -EINVAL  discard packet w/o error
 602          *    sp == NULL, error != 0        discard packet, report error
 603          */
 604         if (sp != NULL) {
 605                 /* Loop detection, check if ipsec processing already done */
 606                 KASSERT(sp->req != NULL, ("ip_output: no ipsec request"));
 607                 for (mtag = m_tag_first(m); mtag != NULL;
 608                      mtag = m_tag_next(m, mtag)) {
 609                         if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
 610                                 continue;
 611                         if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
 612                             mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
 613                                 continue;
 614                         /*
 615                          * Check if policy has an SA associated with it.
 616                          * This can happen when an SP has yet to acquire
 617                          * an SA; e.g. on first reference.  If it occurs,
 618                          * then we let ipsec4_process_packet do its thing.
 619                          */
 620                         if (sp->req->sav == NULL)
 621                                 break;
 622                         tdbi = (struct tdb_ident *)(mtag + 1);
 623                         if (tdbi->spi == sp->req->sav->spi &&
 624                             tdbi->proto == sp->req->sav->sah->saidx.proto &&
 625                             bcmp(&tdbi->dst, &sp->req->sav->sah->saidx.dst,
 626                                  sizeof(union sockaddr_union)) == 0) {
 627                                 /*
 628                                  * No IPsec processing is needed, free
 629                                  * reference to SP.
 630                                  *
 631                                  * NB: null pointer to avoid free at
 632                                  *     done: below.
 633                                  */
 634                                 KEY_FREESP(&sp), sp = NULL;
 635                                 splx(s);
 636                                 goto spd_done;
 637                         }
 638                 }
 639
 640                 /*
 641                  * Do delayed checksums now because we send before
 642                  * this is done in the normal processing path.
 643                  */
 644                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 645                         in_delayed_cksum(m);
 646                         m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
 647                 }
 648
 649                 ip->ip_len = htons(ip->ip_len);
 650                 ip->ip_off = htons(ip->ip_off);
 651
 652                 /* NB: callee frees mbuf */
 653                 error = ipsec4_process_packet(m, sp->req, flags, 0);
 654                 /*
 655                  * Preserve KAME behaviour: ENOENT can be returned
 656                  * when an SA acquire is in progress.  Don't propagate
 657                  * this to user-level; it confuses applications.
 658                  *
 659                  * XXX this will go away when the SADB is redone.
 660                  */
 661                 if (error == ENOENT)
 662                         error = 0;
 663                 splx(s);
 664                 goto done;
 665         } else {
 666                 splx(s);
 667
 668                 if (error != 0) {
 669                         /*
 670                          * Hack: -EINVAL is used to signal that a packet
 671                          * should be silently discarded.  This is typically
 672                          * because we asked key management for an SA and
 673                          * it was delayed (e.g. kicked up to IKE).
 674                          */
 675                         if (error == -EINVAL)
 676                                 error = 0;
 677                         goto bad;
 678                 } else {
 679                         /* No IPsec processing for this packet. */
 680                 }
 681 #ifdef notyet
 682                 /*
 683                  * If deferred crypto processing is needed, check that
 684                  * the interface supports it.
 685                  */
 686                 mtag = m_tag_find(m, PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED, NULL);
 687                 if (mtag != NULL && !(ifp->if_capenable & IFCAP_IPSEC)) {
 688                         /* notify IPsec to do its own crypto */
 689                         ipsp_skipcrypto_unmark((struct tdb_ident *)(mtag + 1));
 690                         error = EHOSTUNREACH;
 691                         goto bad;
 692                 }
 693 #endif
 694         }
 695 spd_done:
 696 #endif /* FAST_IPSEC */
 697         /*
 698          * IpHack's section.
 699          * - Xlate: translate packet's addr/port (NAT).
 700          * - Firewall: deny/allow/etc.
 701          * - Wrap: fake packet's addr/port <unimpl.>
 702          * - Encapsulate: put it in another IP and send out. <unimp.>
 703          */
 704
 705         /*
 706          * Run through list of hooks for output packets.
 707          */
 708         if (pfil_has_hooks(&inet_pfil_hook)) {
 709                 error = pfil_run_hooks(&inet_pfil_hook, &m, ifp, PFIL_OUT);
 710                 if (error != 0 || m == NULL)
 711                         goto done;
 712                 ip = mtod(m, struct ip *);
 713         }
 714
 715         /*
 716          * Check with the firewall...
 717          * but not if we are already being fwd'd from a firewall.
 718          */
 719         if (fw_enable && IPFW_LOADED && !args.next_hop) {
 720                 struct sockaddr_in *old = dst;
 721
 722                 args.m = m;
 723                 args.next_hop = dst;
 724                 args.oif = ifp;
 725                 off = ip_fw_chk_ptr(&args);
 726                 m = args.m;
 727                 dst = args.next_hop;
 728
 729                 /*
 730                  * On return we must do the following:
 731                  * m == NULL    -> drop the pkt (old interface, deprecated)
 732                  * (off & IP_FW_PORT_DENY_FLAG) -> drop the pkt (new interface)
 733                  * 1<=off<= 0xffff              -> DIVERT
 734                  * (off & IP_FW_PORT_DYNT_FLAG) -> send to a DUMMYNET pipe
 735                  * (off & IP_FW_PORT_TEE_FLAG)  -> TEE the packet
 736                  * dst != old                   -> IPFIREWALL_FORWARD
 737                  * off==0, dst==old             -> accept
 738                  * If some of the above modules are not compiled in, then
 739                  * we should't have to check the corresponding condition
 740                  * (because the ipfw control socket should not accept
 741                  * unsupported rules), but better play safe and drop
 742                  * packets in case of doubt.
 743                  */
 744                 if ( (off & IP_FW_PORT_DENY_FLAG) || m == NULL) {
 745                         if (m)
 746                                 m_freem(m);
 747                         error = EACCES;
 748                         goto done;
 749                 }
 750                 ip = mtod(m, struct ip *);
 751                 if (off == 0 && dst == old)             /* common case */
 752                         goto pass;
 753                 if (DUMMYNET_LOADED && (off & IP_FW_PORT_DYNT_FLAG)) {
 754                         /*
 755                          * pass the pkt to dummynet. Need to include
 756                          * pipe number, m, ifp, ro, dst because these are
 757                          * not recomputed in the next pass.
 758                          * All other parameters have been already used and
 759                          * so they are not needed anymore.
 760                          * XXX note: if the ifp or ro entry are deleted
 761                          * while a pkt is in dummynet, we are in trouble!
 762                          */
 763                         args.ro = ro;
 764                         args.dst = dst;
 765                         args.flags = flags;
 766
 767                         error = ip_dn_io_ptr(m, off & 0xffff, DN_TO_IP_OUT,
 768                                 &args);
 769                         goto done;
 770                 }
 771 #ifdef IPDIVERT
 772                 if (off != 0 && !(off & IP_FW_PORT_DYNT_FLAG)) {
 773                         struct mbuf *clone = NULL;
 774
 775                         /* Clone packet if we're doing a 'tee' */
 776                         if ((off & IP_FW_PORT_TEE_FLAG))
 777                                 clone = m_dup(m, MB_DONTWAIT);
 778
 779                         /*
 780                          * XXX
 781                          * delayed checksums are not currently compatible
 782                          * with divert sockets.
 783                          */
 784                         if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 785                                 in_delayed_cksum(m);
 786                                 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
 787                         }
 788
 789                         /* Restore packet header fields to original values */
 790                         ip->ip_len = htons(ip->ip_len);
 791                         ip->ip_off = htons(ip->ip_off);
 792
 793                         /* Deliver packet to divert input routine */
 794                         divert_packet(m, 0, off & 0xffff);
 795
 796                         /* If 'tee', continue with original packet */
 797                         if (clone != NULL) {
 798                                 m = clone;
 799                                 ip = mtod(m, struct ip *);
 800                                 goto pass;
 801                         }
 802                         goto done;
 803                 }
 804 #endif
 805
 806                 /* IPFIREWALL_FORWARD */
 807                 /*
 808                  * Check dst to make sure it is directly reachable on the
 809                  * interface we previously thought it was.
 810                  * If it isn't (which may be likely in some situations) we have
 811                  * to re-route it (ie, find a route for the next-hop and the
 812                  * associated interface) and set them here. This is nested
 813                  * forwarding which in most cases is undesirable, except where
 814                  * such control is nigh impossible. So we do it here.
 815                  * And I'm babbling.
 816                  */
 817                 if (off == 0 && old != dst) { /* FORWARD, dst has changed */
 818 #if 0
 819                         /*
 820                          * XXX To improve readability, this block should be
 821                          * changed into a function call as below:
 822                          */
 823                         error = ip_ipforward(&m, &dst, &ifp);
 824                         if (error)
 825                                 goto bad;
 826                         if (m == NULL) /* ip_input consumed the mbuf */
 827                                 goto done;
 828 #else
 829                         struct in_ifaddr *ia;
 830
 831                         /*
 832                          * XXX sro_fwd below is static, and a pointer
 833                          * to it gets passed to routines downstream.
 834                          * This could have surprisingly bad results in
 835                          * practice, because its content is overwritten
 836                          * by subsequent packets.
 837                          */
 838                         /* There must be a better way to do this next line... */
 839                         static struct route sro_fwd;
 840                         struct route *ro_fwd = &sro_fwd;
 841
 842 #if 0
 843                         print_ip("IPFIREWALL_FORWARD: New dst ip: ",
 844                             dst->sin_addr, "\n");
 845 #endif
 846
 847                         /*
 848                          * We need to figure out if we have been forwarded
 849                          * to a local socket. If so, then we should somehow
 850                          * "loop back" to ip_input, and get directed to the
 851                          * PCB as if we had received this packet. This is
 852                          * because it may be dificult to identify the packets
 853                          * you want to forward until they are being output
 854                          * and have selected an interface. (e.g. locally
 855                          * initiated packets) If we used the loopback inteface,
 856                          * we would not be able to control what happens
 857                          * as the packet runs through ip_input() as
 858                          * it is done through a ISR.
 859                          */
 860                         LIST_FOREACH(ia, INADDR_HASH(dst->sin_addr.s_addr),
 861                                      ia_hash) {
 862                                 /*
 863                                  * If the addr to forward to is one
 864                                  * of ours, we pretend to
 865                                  * be the destination for this packet.
 866                                  */
 867                                 if (IA_SIN(ia)->sin_addr.s_addr ==
 868                                                  dst->sin_addr.s_addr)
 869                                         break;
 870                         }
 871                         if (ia != NULL) {    /* tell ip_input "dont filter" */
 872                                 struct m_hdr tag;
 873
 874                                 tag.mh_type = MT_TAG;
 875                                 tag.mh_flags = PACKET_TAG_IPFORWARD;
 876                                 tag.mh_data = (caddr_t)args.next_hop;
 877                                 tag.mh_next = m;
 878
 879                                 if (m->m_pkthdr.rcvif == NULL)
 880                                         m->m_pkthdr.rcvif = ifunit("lo0");
 881                                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 882                                         m->m_pkthdr.csum_flags |=
 883                                             CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
 884                                         m0->m_pkthdr.csum_data = 0xffff;
 885                                 }
 886                                 m->m_pkthdr.csum_flags |=
 887                                     CSUM_IP_CHECKED | CSUM_IP_VALID;
 888                                 ip->ip_len = htons(ip->ip_len);
 889                                 ip->ip_off = htons(ip->ip_off);
 890                                 ip_input((struct mbuf *)&tag);
 891                                 goto done;
 892                         }
 893                         /* Some of the logic for this was nicked from above.
 894                          *
 895                          * This rewrites the cached route in a local PCB.
 896                          * Is this what we want to do?
 897                          */
 898                         bcopy(dst, &ro_fwd->ro_dst, sizeof *dst);
 899                         ro_fwd->ro_rt = NULL;
 900
 901                         rtalloc_ign(ro_fwd, RTF_PRCLONING);
 902                         if (ro_fwd->ro_rt == NULL) {
 903                                 ipstat.ips_noroute++;
 904                                 error = EHOSTUNREACH;
 905                                 goto bad;
 906                         }
 907
 908                         ia = ifatoia(ro_fwd->ro_rt->rt_ifa);
 909                         ifp = ro_fwd->ro_rt->rt_ifp;
 910                         ro_fwd->ro_rt->rt_use++;
 911                         if (ro_fwd->ro_rt->rt_flags & RTF_GATEWAY)
 912                                 dst = (struct sockaddr_in *)
 913                                     ro_fwd->ro_rt->rt_gateway;
 914                         if (ro_fwd->ro_rt->rt_flags & RTF_HOST)
 915                                 isbroadcast =
 916                                     (ro_fwd->ro_rt->rt_flags & RTF_BROADCAST);
 917                         else
 918                                 isbroadcast = in_broadcast(dst->sin_addr, ifp);
 919                         if (ro->ro_rt != NULL)
 920                                 rtfree(ro->ro_rt);
 921                         ro->ro_rt = ro_fwd->ro_rt;
 922                         dst = (struct sockaddr_in *)&ro_fwd->ro_dst;
 923
 924 #endif  /* ... block to be put into a function */
 925                         /*
 926                          * If we added a default src ip earlier,
 927                          * which would have been gotten from the-then
 928                          * interface, do it again, from the new one.
 929                          */
 930                         if (src_was_INADDR_ANY)
 931                                 ip->ip_src = IA_SIN(ia)->sin_addr;
 932                         goto pass ;
 933                 }
 934
 935                 /*
 936                  * if we get here, none of the above matches, and
 937                  * we have to drop the pkt
 938                  */
 939                 m_freem(m);
 940                 error = EACCES; /* not sure this is the right error msg */
 941                 goto done;
 942         }
 943
 944 pass:
 945         /* 127/8 must not appear on wire - RFC1122. */
 946         if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
 947             (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
 948                 if (!(ifp->if_flags & IFF_LOOPBACK)) {
 949                         ipstat.ips_badaddr++;
 950                         error = EADDRNOTAVAIL;
 951                         goto bad;
 952                 }
 953         }
 954
 955         m->m_pkthdr.csum_flags |= CSUM_IP;
 956         sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_hwassist;
 957         if (sw_csum & CSUM_DELAY_DATA) {
 958                 in_delayed_cksum(m);
 959                 sw_csum &= ~CSUM_DELAY_DATA;
 960         }
 961         m->m_pkthdr.csum_flags &= ifp->if_hwassist;
 962
 963         /*
 964          * If small enough for interface, or the interface will take
 965          * care of the fragmentation for us, can just send directly.
 966          */
 967         if (ip->ip_len <= ifp->if_mtu || ((ifp->if_hwassist & CSUM_FRAGMENT) &&
 968             !(ip->ip_off & IP_DF))) {
 969                 ip->ip_len = htons(ip->ip_len);
 970                 ip->ip_off = htons(ip->ip_off);
 971                 ip->ip_sum = 0;
 972                 if (sw_csum & CSUM_DELAY_IP) {
 973                         if (ip->ip_vhl == IP_VHL_BORING) {
 974                                 ip->ip_sum = in_cksum_hdr(ip);
 975                         } else {
 976                                 ip->ip_sum = in_cksum(m, hlen);
 977                         }
 978                 }
 979
 980                 /* Record statistics for this interface address. */
 981                 if (!(flags & IP_FORWARDING) && ia) {
 982                         ia->ia_ifa.if_opackets++;
 983                         ia->ia_ifa.if_obytes += m->m_pkthdr.len;
 984                 }
 985
 986 #ifdef IPSEC
 987                 /* clean ipsec history once it goes out of the node */
 988                 ipsec_delaux(m);
 989 #endif
 990
 991 #ifdef MBUF_STRESS_TEST
 992                 if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size) {
 993                         struct mbuf *m1, *m2;
 994                         int length, tmp;
 995
 996                         tmp = length = m->m_pkthdr.len;
 997
 998                         while ((length -= mbuf_frag_size) >= 1) {
 999                                 m1 = m_split(m, length, MB_DONTWAIT);
1000                                 if (m1 == NULL)
1001                                         break;
1002                                 m1->m_flags &= ~M_PKTHDR;
1003                                 m2 = m;
1004                                 while (m2->m_next != NULL)
1005                                         m2 = m2->m_next;
1006                                 m2->m_next = m1;
1007                         }
1008                         m->m_pkthdr.len = tmp;
1009                 }
1010 #endif
1011                 error = (*ifp->if_output)(ifp, m, (struct sockaddr *)dst,
1012                                           ro->ro_rt);
1013                 goto done;
1014         }
1015
1016         if (ip->ip_off & IP_DF) {
1017                 error = EMSGSIZE;
1018                 /*
1019                  * This case can happen if the user changed the MTU
1020                  * of an interface after enabling IP on it.  Because
1021                  * most netifs don't keep track of routes pointing to
1022                  * them, there is no way for one to update all its
1023                  * routes when the MTU is changed.
1024                  */
1025                 if ((ro->ro_rt->rt_flags & (RTF_UP | RTF_HOST)) &&
1026                     !(ro->ro_rt->rt_rmx.rmx_locks & RTV_MTU) &&
1027                     (ro->ro_rt->rt_rmx.rmx_mtu > ifp->if_mtu)) {
1028                         ro->ro_rt->rt_rmx.rmx_mtu = ifp->if_mtu;
1029                 }
1030                 ipstat.ips_cantfrag++;
1031                 goto bad;
1032         }
1033
1034         /*
1035          * Too large for interface; fragment if possible. If successful,
1036          * on return, m will point to a list of packets to be sent.
1037          */
1038         error = ip_fragment(ip, &m, ifp->if_mtu, ifp->if_hwassist, sw_csum);
1039         if (error)
1040                 goto bad;
1041         for (; m; m = m0) {
1042                 m0 = m->m_nextpkt;
1043                 m->m_nextpkt = NULL;
1044 #ifdef IPSEC
1045                 /* clean ipsec history once it goes out of the node */
1046                 ipsec_delaux(m);
1047 #endif
1048                 if (error == 0) {
1049                         /* Record statistics for this interface address. */
1050                         if (ia != NULL) {
1051                                 ia->ia_ifa.if_opackets++;
1052                                 ia->ia_ifa.if_obytes += m->m_pkthdr.len;
1053                         }
1054                         error = (*ifp->if_output)(ifp, m,
1055                                                   (struct sockaddr *)dst,
1056                                                   ro->ro_rt);
1057                 } else
1058                         m_freem(m);
1059         }
1060
1061         if (error == 0)
1062                 ipstat.ips_fragmented++;
1063
1064 done:
1065         if (ro == &iproute && ro->ro_rt != NULL) {
1066                 RTFREE(ro->ro_rt);
1067                 ro->ro_rt = NULL;
1068         }
1069 #ifdef IPSEC
1070         if (sp != NULL) {
1071                 KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
1072                         printf("DP ip_output call free SP:%p\n", sp));
1073                 key_freesp(sp);
1074         }
1075 #endif
1076 #ifdef FAST_IPSEC
1077         if (sp != NULL)
1078                 KEY_FREESP(&sp);
1079 #endif
1080         return (error);
1081 bad:
1082         m_freem(m);
1083         goto done;
1084 }
1085
1086 /*
1087  * Create a chain of fragments which fit the given mtu. m_frag points to the
1088  * mbuf to be fragmented; on return it points to the chain with the fragments.
1089  * Return 0 if no error. If error, m_frag may contain a partially built
1090  * chain of fragments that should be freed by the caller.
1091  *
1092  * if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist)
1093  * sw_csum contains the delayed checksums flags (e.g., CSUM_DELAY_IP).
1094  */
1095 int
1096 ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu,
1097             u_long if_hwassist_flags, int sw_csum)
1098 {
1099         int error = 0;
1100         int hlen = IP_VHL_HL(ip->ip_vhl) << 2;
1101         int len = (mtu - hlen) & ~7;    /* size of payload in each fragment */
1102         int off;
1103         struct mbuf *m0 = *m_frag;      /* the original packet          */
1104         int firstlen;
1105         struct mbuf **mnext;
1106         int nfrags;
1107
1108         if (ip->ip_off & IP_DF) {       /* Fragmentation not allowed */
1109                 ipstat.ips_cantfrag++;
1110                 return EMSGSIZE;
1111         }
1112
1113         /*
1114          * Must be able to put at least 8 bytes per fragment.
1115          */
1116         if (len < 8)
1117                 return EMSGSIZE;
1118
1119         /*
1120          * If the interface will not calculate checksums on
1121          * fragmented packets, then do it here.
1122          */
1123         if ((m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA) &&
1124             !(if_hwassist_flags & CSUM_IP_FRAGS)) {
1125                 in_delayed_cksum(m0);
1126                 m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
1127         }
1128
1129         if (len > PAGE_SIZE) {
1130                 /*
1131                  * Fragment large datagrams such that each segment
1132                  * contains a multiple of PAGE_SIZE amount of data,
1133                  * plus headers. This enables a receiver to perform
1134                  * page-flipping zero-copy optimizations.
1135                  *
1136                  * XXX When does this help given that sender and receiver
1137                  * could have different page sizes, and also mtu could
1138                  * be less than the receiver's page size ?
1139                  */
1140                 int newlen;
1141                 struct mbuf *m;
1142
1143                 for (m = m0, off = 0; m && (off+m->m_len) <= mtu; m = m->m_next)
1144                         off += m->m_len;
1145
1146                 /*
1147                  * firstlen (off - hlen) must be aligned on an
1148                  * 8-byte boundary
1149                  */
1150                 if (off < hlen)
1151                         goto smart_frag_failure;
1152                 off = ((off - hlen) & ~7) + hlen;
1153                 newlen = (~PAGE_MASK) & mtu;
1154                 if ((newlen + sizeof(struct ip)) > mtu) {
1155                         /* we failed, go back the default */
1156 smart_frag_failure:
1157                         newlen = len;
1158                         off = hlen + len;
1159                 }
1160                 len = newlen;
1161
1162         } else {
1163                 off = hlen + len;
1164         }
1165
1166         firstlen = off - hlen;
1167         mnext = &m0->m_nextpkt;         /* pointer to next packet */
1168
1169         /*
1170          * Loop through length of segment after first fragment,
1171          * make new header and copy data of each part and link onto chain.
1172          * Here, m0 is the original packet, m is the fragment being created.
1173          * The fragments are linked off the m_nextpkt of the original
1174          * packet, which after processing serves as the first fragment.
1175          */
1176         for (nfrags = 1; off < ip->ip_len; off += len, nfrags++) {
1177                 struct ip *mhip;        /* ip header on the fragment */
1178                 struct mbuf *m;
1179                 int mhlen = sizeof(struct ip);
1180
1181                 MGETHDR(m, MB_DONTWAIT, MT_HEADER);
1182                 if (m == NULL) {
1183                         error = ENOBUFS;
1184                         ipstat.ips_odropped++;
1185                         goto done;
1186                 }
1187                 m->m_flags |= (m0->m_flags & M_MCAST) | M_FRAG;
1188                 /*
1189                  * In the first mbuf, leave room for the link header, then
1190                  * copy the original IP header including options. The payload
1191                  * goes into an additional mbuf chain returned by m_copy().
1192                  */
1193                 m->m_data += max_linkhdr;
1194                 mhip = mtod(m, struct ip *);
1195                 *mhip = *ip;
1196                 if (hlen > sizeof(struct ip)) {
1197                         mhlen = ip_optcopy(ip, mhip) + sizeof(struct ip);
1198                         mhip->ip_vhl = IP_MAKE_VHL(IPVERSION, mhlen >> 2);
1199                 }
1200                 m->m_len = mhlen;
1201                 /* XXX do we need to add ip->ip_off below ? */
1202                 mhip->ip_off = ((off - hlen) >> 3) + ip->ip_off;
1203                 if (off + len >= ip->ip_len) {  /* last fragment */
1204                         len = ip->ip_len - off;
1205                         m->m_flags |= M_LASTFRAG;
1206                 } else
1207                         mhip->ip_off |= IP_MF;
1208                 mhip->ip_len = htons((u_short)(len + mhlen));
1209                 m->m_next = m_copy(m0, off, len);
1210                 if (m->m_next == NULL) {                /* copy failed */
1211                         m_free(m);
1212                         error = ENOBUFS;        /* ??? */
1213                         ipstat.ips_odropped++;
1214                         goto done;
1215                 }
1216                 m->m_pkthdr.len = mhlen + len;
1217                 m->m_pkthdr.rcvif = (struct ifnet *)NULL;
1218                 m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags;
1219                 mhip->ip_off = htons(mhip->ip_off);
1220                 mhip->ip_sum = 0;
1221                 if (sw_csum & CSUM_DELAY_IP)
1222                         mhip->ip_sum = in_cksum(m, mhlen);
1223                 *mnext = m;
1224                 mnext = &m->m_nextpkt;
1225         }
1226         ipstat.ips_ofragments += nfrags;
1227
1228         /* set first marker for fragment chain */
1229         m0->m_flags |= M_FIRSTFRAG | M_FRAG;
1230         m0->m_pkthdr.csum_data = nfrags;
1231
1232         /*
1233          * Update first fragment by trimming what's been copied out
1234          * and updating header.
1235          */
1236         m_adj(m0, hlen + firstlen - ip->ip_len);
1237         m0->m_pkthdr.len = hlen + firstlen;
1238         ip->ip_len = htons((u_short)m0->m_pkthdr.len);
1239         ip->ip_off |= IP_MF;
1240         ip->ip_off = htons(ip->ip_off);
1241         ip->ip_sum = 0;
1242         if (sw_csum & CSUM_DELAY_IP)
1243                 ip->ip_sum = in_cksum(m0, hlen);
1244
1245 done:
1246         *m_frag = m0;
1247         return error;
1248 }
1249
1250 void
1251 in_delayed_cksum(struct mbuf *m)
1252 {
1253         struct ip *ip;
1254         u_short csum, offset;
1255
1256         ip = mtod(m, struct ip *);
1257         offset = IP_VHL_HL(ip->ip_vhl) << 2 ;
1258         csum = in_cksum_skip(m, ip->ip_len, offset);
1259         if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0)
1260                 csum = 0xffff;
1261         offset += m->m_pkthdr.csum_data;        /* checksum offset */
1262
1263         if (offset + sizeof(u_short) > m->m_len) {
1264                 printf("delayed m_pullup, m->len: %d  off: %d  p: %d\n",
1265                     m->m_len, offset, ip->ip_p);
1266                 /*
1267                  * XXX
1268                  * this shouldn't happen, but if it does, the
1269                  * correct behavior may be to insert the checksum
1270                  * in the existing chain instead of rearranging it.
1271                  */
1272                 m = m_pullup(m, offset + sizeof(u_short));
1273         }
1274         *(u_short *)(m->m_data + offset) = csum;
1275 }
1276
1277 /*
1278  * Insert IP options into preformed packet.
1279  * Adjust IP destination as required for IP source routing,
1280  * as indicated by a non-zero in_addr at the start of the options.
1281  *
1282  * XXX This routine assumes that the packet has no options in place.
1283  */
1284 static struct mbuf *
1285 ip_insertoptions(struct mbuf *m, struct mbuf *opt, int *phlen)
1286 {
1287         struct ipoption *p = mtod(opt, struct ipoption *);
1288         struct mbuf *n;
1289         struct ip *ip = mtod(m, struct ip *);
1290         unsigned optlen;
1291
1292         optlen = opt->m_len - sizeof p->ipopt_dst;
1293         if (optlen + (u_short)ip->ip_len > IP_MAXPACKET) {
1294                 *phlen = 0;
1295                 return (m);             /* XXX should fail */
1296         }
1297         if (p->ipopt_dst.s_addr)
1298                 ip->ip_dst = p->ipopt_dst;
1299         if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) {
1300                 MGETHDR(n, MB_DONTWAIT, MT_HEADER);
1301                 if (n == NULL) {
1302                         *phlen = 0;
1303                         return (m);
1304                 }
1305                 n->m_pkthdr.rcvif = (struct ifnet *)NULL;
1306                 n->m_pkthdr.len = m->m_pkthdr.len + optlen;
1307                 m->m_len -= sizeof(struct ip);
1308                 m->m_data += sizeof(struct ip);
1309                 n->m_next = m;
1310                 m = n;
1311                 m->m_len = optlen + sizeof(struct ip);
1312                 m->m_data += max_linkhdr;
1313                 memcpy(mtod(m, void *), ip, sizeof(struct ip));
1314         } else {
1315                 m->m_data -= optlen;
1316                 m->m_len += optlen;
1317                 m->m_pkthdr.len += optlen;
1318                 ovbcopy(ip, mtod(m, caddr_t), sizeof(struct ip));
1319         }
1320         ip = mtod(m, struct ip *);
1321         bcopy(p->ipopt_list, ip + 1, optlen);
1322         *phlen = sizeof(struct ip) + optlen;
1323         ip->ip_vhl = IP_MAKE_VHL(IPVERSION, *phlen >> 2);
1324         ip->ip_len += optlen;
1325         return (m);
1326 }
1327
1328 /*
1329  * Copy options from ip to jp,
1330  * omitting those not copied during fragmentation.
1331  */
1332 int
1333 ip_optcopy(struct ip *ip, struct ip *jp)
1334 {
1335         u_char *cp, *dp;
1336         int opt, optlen, cnt;
1337
1338         cp = (u_char *)(ip + 1);
1339         dp = (u_char *)(jp + 1);
1340         cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip);
1341         for (; cnt > 0; cnt -= optlen, cp += optlen) {
1342                 opt = cp[0];
1343                 if (opt == IPOPT_EOL)
1344                         break;
1345                 if (opt == IPOPT_NOP) {
1346                         /* Preserve for IP mcast tunnel's LSRR alignment. */
1347                         *dp++ = IPOPT_NOP;
1348                         optlen = 1;
1349                         continue;
1350                 }
1351
1352                 KASSERT(cnt >= IPOPT_OLEN + sizeof *cp,
1353                     ("ip_optcopy: malformed ipv4 option"));
1354                 optlen = cp[IPOPT_OLEN];
1355                 KASSERT(optlen >= IPOPT_OLEN + sizeof *cp && optlen <= cnt,
1356                     ("ip_optcopy: malformed ipv4 option"));
1357
1358                 /* bogus lengths should have been caught by ip_dooptions */
1359                 if (optlen > cnt)
1360                         optlen = cnt;
1361                 if (IPOPT_COPIED(opt)) {
1362                         bcopy(cp, dp, optlen);
1363                         dp += optlen;
1364                 }
1365         }
1366         for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++)
1367                 *dp++ = IPOPT_EOL;
1368         return (optlen);
1369 }
1370
1371 /*
1372  * IP socket option processing.
1373  */
1374 int
1375 ip_ctloutput(struct socket *so, struct sockopt *sopt)
1376 {
1377         struct  inpcb *inp = so->so_pcb;
1378         int     error, optval;
1379
1380         error = optval = 0;
1381         if (sopt->sopt_level != IPPROTO_IP) {
1382                 return (EINVAL);
1383         }
1384
1385         switch (sopt->sopt_dir) {
1386         case SOPT_SET:
1387                 switch (sopt->sopt_name) {
1388                 case IP_OPTIONS:
1389 #ifdef notyet
1390                 case IP_RETOPTS:
1391 #endif
1392                 {
1393                         struct mbuf *m;
1394                         if (sopt->sopt_valsize > MLEN) {
1395                                 error = EMSGSIZE;
1396                                 break;
1397                         }
1398                         MGET(m, sopt->sopt_td ? MB_WAIT : MB_DONTWAIT, MT_HEADER);
1399                         if (m == NULL) {
1400                                 error = ENOBUFS;
1401                                 break;
1402                         }
1403                         m->m_len = sopt->sopt_valsize;
1404                         error = sooptcopyin(sopt, mtod(m, char *), m->m_len,
1405                                             m->m_len);
1406
1407                         return (ip_pcbopts(sopt->sopt_name, &inp->inp_options,
1408                                            m));
1409                 }
1410
1411                 case IP_TOS:
1412                 case IP_TTL:
1413                 case IP_RECVOPTS:
1414                 case IP_RECVRETOPTS:
1415                 case IP_RECVDSTADDR:
1416                 case IP_RECVIF:
1417                 case IP_FAITH:
1418                         error = sooptcopyin(sopt, &optval, sizeof optval,
1419                                             sizeof optval);
1420                         if (error)
1421                                 break;
1422
1423                         switch (sopt->sopt_name) {
1424                         case IP_TOS:
1425                                 inp->inp_ip_tos = optval;
1426                                 break;
1427
1428                         case IP_TTL:
1429                                 inp->inp_ip_ttl = optval;
1430                                 break;
1431 #define OPTSET(bit) \
1432         if (optval) \
1433                 inp->inp_flags |= bit; \
1434         else \
1435                 inp->inp_flags &= ~bit;
1436
1437                         case IP_RECVOPTS:
1438                                 OPTSET(INP_RECVOPTS);
1439                                 break;
1440
1441                         case IP_RECVRETOPTS:
1442                                 OPTSET(INP_RECVRETOPTS);
1443                                 break;
1444
1445                         case IP_RECVDSTADDR:
1446                                 OPTSET(INP_RECVDSTADDR);
1447                                 break;
1448
1449                         case IP_RECVIF:
1450                                 OPTSET(INP_RECVIF);
1451                                 break;
1452
1453                         case IP_FAITH:
1454                                 OPTSET(INP_FAITH);
1455                                 break;
1456                         }
1457                         break;
1458 #undef OPTSET
1459
1460                 case IP_MULTICAST_IF:
1461                 case IP_MULTICAST_VIF:
1462                 case IP_MULTICAST_TTL:
1463                 case IP_MULTICAST_LOOP:
1464                 case IP_ADD_MEMBERSHIP:
1465                 case IP_DROP_MEMBERSHIP:
1466                         error = ip_setmoptions(sopt, &inp->inp_moptions);
1467                         break;
1468
1469                 case IP_PORTRANGE:
1470                         error = sooptcopyin(sopt, &optval, sizeof optval,
1471                                             sizeof optval);
1472                         if (error)
1473                                 break;
1474
1475                         switch (optval) {
1476                         case IP_PORTRANGE_DEFAULT:
1477                                 inp->inp_flags &= ~(INP_LOWPORT);
1478                                 inp->inp_flags &= ~(INP_HIGHPORT);
1479                                 break;
1480
1481                         case IP_PORTRANGE_HIGH:
1482                                 inp->inp_flags &= ~(INP_LOWPORT);
1483                                 inp->inp_flags |= INP_HIGHPORT;
1484                                 break;
1485
1486                         case IP_PORTRANGE_LOW:
1487                                 inp->inp_flags &= ~(INP_HIGHPORT);
1488                                 inp->inp_flags |= INP_LOWPORT;
1489                                 break;
1490
1491                         default:
1492                                 error = EINVAL;
1493                                 break;
1494                         }
1495                         break;
1496
1497 #if defined(IPSEC) || defined(FAST_IPSEC)
1498                 case IP_IPSEC_POLICY:
1499                 {
1500                         caddr_t req;
1501                         size_t len = 0;
1502                         int priv;
1503                         struct mbuf *m;
1504                         int optname;
1505
1506                         if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */
1507                                 break;
1508                         if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */
1509                                 break;
1510                         priv = (sopt->sopt_td != NULL &&
1511                                 suser(sopt->sopt_td) != 0) ? 0 : 1;
1512                         req = mtod(m, caddr_t);
1513                         len = m->m_len;
1514                         optname = sopt->sopt_name;
1515                         error = ipsec4_set_policy(inp, optname, req, len, priv);
1516                         m_freem(m);
1517                         break;
1518                 }
1519 #endif /*IPSEC*/
1520
1521                 default:
1522                         error = ENOPROTOOPT;
1523                         break;
1524                 }
1525                 break;
1526
1527         case SOPT_GET:
1528                 switch (sopt->sopt_name) {
1529                 case IP_OPTIONS:
1530                 case IP_RETOPTS:
1531                         if (inp->inp_options)
1532                                 error = sooptcopyout(sopt,
1533                                                      mtod(inp->inp_options,
1534                                                           char *),
1535                                                      inp->inp_options->m_len);
1536                         else
1537                                 sopt->sopt_valsize = 0;
1538                         break;
1539
1540                 case IP_TOS:
1541                 case IP_TTL:
1542                 case IP_RECVOPTS:
1543                 case IP_RECVRETOPTS:
1544                 case IP_RECVDSTADDR:
1545                 case IP_RECVIF:
1546                 case IP_PORTRANGE:
1547                 case IP_FAITH:
1548                         switch (sopt->sopt_name) {
1549
1550                         case IP_TOS:
1551                                 optval = inp->inp_ip_tos;
1552                                 break;
1553
1554                         case IP_TTL:
1555                                 optval = inp->inp_ip_ttl;
1556                                 break;
1557
1558 #define OPTBIT(bit)     (inp->inp_flags & bit ? 1 : 0)
1559
1560                         case IP_RECVOPTS:
1561                                 optval = OPTBIT(INP_RECVOPTS);
1562                                 break;
1563
1564                         case IP_RECVRETOPTS:
1565                                 optval = OPTBIT(INP_RECVRETOPTS);
1566                                 break;
1567
1568                         case IP_RECVDSTADDR:
1569                                 optval = OPTBIT(INP_RECVDSTADDR);
1570                                 break;
1571
1572                         case IP_RECVIF:
1573                                 optval = OPTBIT(INP_RECVIF);
1574                                 break;
1575
1576                         case IP_PORTRANGE:
1577                                 if (inp->inp_flags & INP_HIGHPORT)
1578                                         optval = IP_PORTRANGE_HIGH;
1579                                 else if (inp->inp_flags & INP_LOWPORT)
1580                                         optval = IP_PORTRANGE_LOW;
1581                                 else
1582                                         optval = 0;
1583                                 break;
1584
1585                         case IP_FAITH:
1586                                 optval = OPTBIT(INP_FAITH);
1587                                 break;
1588                         }
1589                         error = sooptcopyout(sopt, &optval, sizeof optval);
1590                         break;
1591
1592                 case IP_MULTICAST_IF:
1593                 case IP_MULTICAST_VIF:
1594                 case IP_MULTICAST_TTL:
1595                 case IP_MULTICAST_LOOP:
1596                 case IP_ADD_MEMBERSHIP:
1597                 case IP_DROP_MEMBERSHIP:
1598                         error = ip_getmoptions(sopt, inp->inp_moptions);
1599                         break;
1600
1601 #if defined(IPSEC) || defined(FAST_IPSEC)
1602                 case IP_IPSEC_POLICY:
1603                 {
1604                         struct mbuf *m = NULL;
1605                         caddr_t req = NULL;
1606                         size_t len = 0;
1607
1608                         if (m != NULL) {
1609                                 req = mtod(m, caddr_t);
1610                                 len = m->m_len;
1611                         }
1612                         error = ipsec4_get_policy(so->so_pcb, req, len, &m);
1613                         if (error == 0)
1614                                 error = soopt_mcopyout(sopt, m); /* XXX */
1615                         if (error == 0)
1616                                 m_freem(m);
1617                         break;
1618                 }
1619 #endif /*IPSEC*/
1620
1621                 default:
1622                         error = ENOPROTOOPT;
1623                         break;
1624                 }
1625                 break;
1626         }
1627         return (error);
1628 }
1629
1630 /*
1631  * Set up IP options in pcb for insertion in output packets.
1632  * Store in mbuf with pointer in pcbopt, adding pseudo-option
1633  * with destination address if source routed.
1634  */
1635 static int
1636 ip_pcbopts(int optname, struct mbuf **pcbopt, struct mbuf *m)
1637 {
1638         int cnt, optlen;
1639         u_char *cp;
1640         u_char opt;
1641
1642         /* turn off any old options */
1643         if (*pcbopt)
1644                 m_free(*pcbopt);
1645         *pcbopt = 0;
1646         if (m == NULL || m->m_len == 0) {
1647                 /*
1648                  * Only turning off any previous options.
1649                  */
1650                 if (m != NULL)
1651                         m_free(m);
1652                 return (0);
1653         }
1654
1655         if (m->m_len % sizeof(int32_t))
1656                 goto bad;
1657         /*
1658          * IP first-hop destination address will be stored before
1659          * actual options; move other options back
1660          * and clear it when none present.
1661          */
1662         if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN])
1663                 goto bad;
1664         cnt = m->m_len;
1665         m->m_len += sizeof(struct in_addr);
1666         cp = mtod(m, u_char *) + sizeof(struct in_addr);
1667         ovbcopy(mtod(m, caddr_t), cp, cnt);
1668         bzero(mtod(m, caddr_t), sizeof(struct in_addr));
1669
1670         for (; cnt > 0; cnt -= optlen, cp += optlen) {
1671                 opt = cp[IPOPT_OPTVAL];
1672                 if (opt == IPOPT_EOL)
1673                         break;
1674                 if (opt == IPOPT_NOP)
1675                         optlen = 1;
1676                 else {
1677                         if (cnt < IPOPT_OLEN + sizeof *cp)
1678                                 goto bad;
1679                         optlen = cp[IPOPT_OLEN];
1680                         if (optlen < IPOPT_OLEN + sizeof *cp || optlen > cnt)
1681                                 goto bad;
1682                 }
1683                 switch (opt) {
1684
1685                 default:
1686                         break;
1687
1688                 case IPOPT_LSRR:
1689                 case IPOPT_SSRR:
1690                         /*
1691                          * user process specifies route as:
1692                          *      ->A->B->C->D
1693                          * D must be our final destination (but we can't
1694                          * check that since we may not have connected yet).
1695                          * A is first hop destination, which doesn't appear in
1696                          * actual IP option, but is stored before the options.
1697                          */
1698                         if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr))
1699                                 goto bad;
1700                         m->m_len -= sizeof(struct in_addr);
1701                         cnt -= sizeof(struct in_addr);
1702                         optlen -= sizeof(struct in_addr);
1703                         cp[IPOPT_OLEN] = optlen;
1704                         /*
1705                          * Move first hop before start of options.
1706                          */
1707                         bcopy(&cp[IPOPT_OFFSET+1], mtod(m, caddr_t),
1708                               sizeof(struct in_addr));
1709                         /*
1710                          * Then copy rest of options back
1711                          * to close up the deleted entry.
1712                          */
1713                         ovbcopy(&cp[IPOPT_OFFSET+1] + sizeof(struct in_addr),
1714                                 &cp[IPOPT_OFFSET+1],
1715                                 cnt - (IPOPT_MINOFF - 1));
1716                         break;
1717                 }
1718         }
1719         if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr))
1720                 goto bad;
1721         *pcbopt = m;
1722         return (0);
1723
1724 bad:
1725         m_free(m);
1726         return (EINVAL);
1727 }
1728
1729 /*
1730  * XXX
1731  * The whole multicast option thing needs to be re-thought.
1732  * Several of these options are equally applicable to non-multicast
1733  * transmission, and one (IP_MULTICAST_TTL) totally duplicates a
1734  * standard option (IP_TTL).
1735  */
1736
1737 /*
1738  * following RFC1724 section 3.3, 0.0.0.0/8 is interpreted as interface index.
1739  */
1740 static struct ifnet *
1741 ip_multicast_if(struct in_addr *a, int *ifindexp)
1742 {
1743         int ifindex;
1744         struct ifnet *ifp;
1745
1746         if (ifindexp)
1747                 *ifindexp = 0;
1748         if (ntohl(a->s_addr) >> 24 == 0) {
1749                 ifindex = ntohl(a->s_addr) & 0xffffff;
1750                 if (ifindex < 0 || if_index < ifindex)
1751                         return NULL;
1752                 ifp = ifindex2ifnet[ifindex];
1753                 if (ifindexp)
1754                         *ifindexp = ifindex;
1755         } else {
1756                 INADDR_TO_IFP(*a, ifp);
1757         }
1758         return ifp;
1759 }
1760
1761 /*
1762  * Set the IP multicast options in response to user setsockopt().
1763  */
1764 static int
1765 ip_setmoptions(struct sockopt *sopt, struct ip_moptions **imop)
1766 {
1767         int error = 0;
1768         int i;
1769         struct in_addr addr;
1770         struct ip_mreq mreq;
1771         struct ifnet *ifp;
1772         struct ip_moptions *imo = *imop;
1773         int ifindex;
1774         int s;
1775
1776         if (imo == NULL) {
1777                 /*
1778                  * No multicast option buffer attached to the pcb;
1779                  * allocate one and initialize to default values.
1780                  */
1781                 imo = malloc(sizeof *imo, M_IPMOPTS, M_WAITOK);
1782
1783                 if (imo == NULL)
1784                         return (ENOBUFS);
1785                 *imop = imo;
1786                 imo->imo_multicast_ifp = NULL;
1787                 imo->imo_multicast_addr.s_addr = INADDR_ANY;
1788                 imo->imo_multicast_vif = -1;
1789                 imo->imo_multicast_ttl = IP_DEFAULT_MULTICAST_TTL;
1790                 imo->imo_multicast_loop = IP_DEFAULT_MULTICAST_LOOP;
1791                 imo->imo_num_memberships = 0;
1792         }
1793
1794         switch (sopt->sopt_name) {
1795         /* store an index number for the vif you wanna use in the send */
1796         case IP_MULTICAST_VIF:
1797                 if (legal_vif_num == 0) {
1798                         error = EOPNOTSUPP;
1799                         break;
1800                 }
1801                 error = sooptcopyin(sopt, &i, sizeof i, sizeof i);
1802                 if (error)
1803                         break;
1804                 if (!legal_vif_num(i) && (i != -1)) {
1805                         error = EINVAL;
1806                         break;
1807                 }
1808                 imo->imo_multicast_vif = i;
1809                 break;
1810
1811         case IP_MULTICAST_IF:
1812                 /*
1813                  * Select the interface for outgoing multicast packets.
1814                  */
1815                 error = sooptcopyin(sopt, &addr, sizeof addr, sizeof addr);
1816                 if (error)
1817                         break;
1818                 /*
1819                  * INADDR_ANY is used to remove a previous selection.
1820                  * When no interface is selected, a default one is
1821                  * chosen every time a multicast packet is sent.
1822                  */
1823                 if (addr.s_addr == INADDR_ANY) {
1824                         imo->imo_multicast_ifp = NULL;
1825                         break;
1826                 }
1827                 /*
1828                  * The selected interface is identified by its local
1829                  * IP address.  Find the interface and confirm that
1830                  * it supports multicasting.
1831                  */
1832                 s = splimp();
1833                 ifp = ip_multicast_if(&addr, &ifindex);
1834                 if (ifp == NULL || !(ifp->if_flags & IFF_MULTICAST)) {
1835                         splx(s);
1836                         error = EADDRNOTAVAIL;
1837                         break;
1838                 }
1839                 imo->imo_multicast_ifp = ifp;
1840                 if (ifindex)
1841                         imo->imo_multicast_addr = addr;
1842                 else
1843                         imo->imo_multicast_addr.s_addr = INADDR_ANY;
1844                 splx(s);
1845                 break;
1846
1847         case IP_MULTICAST_TTL:
1848                 /*
1849                  * Set the IP time-to-live for outgoing multicast packets.
1850                  * The original multicast API required a char argument,
1851                  * which is inconsistent with the rest of the socket API.
1852                  * We allow either a char or an int.
1853                  */
1854                 if (sopt->sopt_valsize == 1) {
1855                         u_char ttl;
1856                         error = sooptcopyin(sopt, &ttl, 1, 1);
1857                         if (error)
1858                                 break;
1859                         imo->imo_multicast_ttl = ttl;
1860                 } else {
1861                         u_int ttl;
1862                         error = sooptcopyin(sopt, &ttl, sizeof ttl, sizeof ttl);
1863                         if (error)
1864                                 break;
1865                         if (ttl > 255)
1866                                 error = EINVAL;
1867                         else
1868                                 imo->imo_multicast_ttl = ttl;
1869                 }
1870                 break;
1871
1872         case IP_MULTICAST_LOOP:
1873                 /*
1874                  * Set the loopback flag for outgoing multicast packets.
1875                  * Must be zero or one.  The original multicast API required a
1876                  * char argument, which is inconsistent with the rest
1877                  * of the socket API.  We allow either a char or an int.
1878                  */
1879                 if (sopt->sopt_valsize == 1) {
1880                         u_char loop;
1881
1882                         error = sooptcopyin(sopt, &loop, 1, 1);
1883                         if (error)
1884                                 break;
1885                         imo->imo_multicast_loop = !!loop;
1886                 } else {
1887                         u_int loop;
1888
1889                         error = sooptcopyin(sopt, &loop, sizeof loop,
1890                                             sizeof loop);
1891                         if (error)
1892                                 break;
1893                         imo->imo_multicast_loop = !!loop;
1894                 }
1895                 break;
1896
1897         case IP_ADD_MEMBERSHIP:
1898                 /*
1899                  * Add a multicast group membership.
1900                  * Group must be a valid IP multicast address.
1901                  */
1902                 error = sooptcopyin(sopt, &mreq, sizeof mreq, sizeof mreq);
1903                 if (error)
1904                         break;
1905
1906                 if (!IN_MULTICAST(ntohl(mreq.imr_multiaddr.s_addr))) {
1907                         error = EINVAL;
1908                         break;
1909                 }
1910                 s = splimp();
1911                 /*
1912                  * If no interface address was provided, use the interface of
1913                  * the route to the given multicast address.
1914                  */
1915                 if (mreq.imr_interface.s_addr == INADDR_ANY) {
1916                         struct sockaddr_in dst;
1917                         struct rtentry *rt;
1918
1919                         bzero(&dst, sizeof(struct sockaddr_in));
1920                         dst.sin_len = sizeof(struct sockaddr_in);
1921                         dst.sin_family = AF_INET;
1922                         dst.sin_addr = mreq.imr_multiaddr;
1923                         rt = rtlookup((struct sockaddr *)&dst);
1924                         if (rt == NULL) {
1925                                 error = EADDRNOTAVAIL;
1926                                 splx(s);
1927                                 break;
1928                         }
1929                         --rt->rt_refcnt;
1930                         ifp = rt->rt_ifp;
1931                 } else {
1932                         ifp = ip_multicast_if(&mreq.imr_interface, NULL);
1933                 }
1934
1935                 /*
1936                  * See if we found an interface, and confirm that it
1937                  * supports multicast.
1938                  */
1939                 if (ifp == NULL || !(ifp->if_flags & IFF_MULTICAST)) {
1940                         error = EADDRNOTAVAIL;
1941                         splx(s);
1942                         break;
1943                 }
1944                 /*
1945                  * See if the membership already exists or if all the
1946                  * membership slots are full.
1947                  */
1948                 for (i = 0; i < imo->imo_num_memberships; ++i) {
1949                         if (imo->imo_membership[i]->inm_ifp == ifp &&
1950                             imo->imo_membership[i]->inm_addr.s_addr
1951                                                 == mreq.imr_multiaddr.s_addr)
1952                                 break;
1953                 }
1954                 if (i < imo->imo_num_memberships) {
1955                         error = EADDRINUSE;
1956                         splx(s);
1957                         break;
1958                 }
1959                 if (i == IP_MAX_MEMBERSHIPS) {
1960                         error = ETOOMANYREFS;
1961                         splx(s);
1962                         break;
1963                 }
1964                 /*
1965                  * Everything looks good; add a new record to the multicast
1966                  * address list for the given interface.
1967                  */
1968                 if ((imo->imo_membership[i] =
1969                      in_addmulti(&mreq.imr_multiaddr, ifp)) == NULL) {
1970                         error = ENOBUFS;
1971                         splx(s);
1972                         break;
1973                 }
1974                 ++imo->imo_num_memberships;
1975                 splx(s);
1976                 break;
1977
1978         case IP_DROP_MEMBERSHIP:
1979                 /*
1980                  * Drop a multicast group membership.
1981                  * Group must be a valid IP multicast address.
1982                  */
1983                 error = sooptcopyin(sopt, &mreq, sizeof mreq, sizeof mreq);
1984                 if (error)
1985                         break;
1986
1987                 if (!IN_MULTICAST(ntohl(mreq.imr_multiaddr.s_addr))) {
1988                         error = EINVAL;
1989                         break;
1990                 }
1991
1992                 s = splimp();
1993                 /*
1994                  * If an interface address was specified, get a pointer
1995                  * to its ifnet structure.
1996                  */
1997                 if (mreq.imr_interface.s_addr == INADDR_ANY)
1998                         ifp = NULL;
1999                 else {
2000                         ifp = ip_multicast_if(&mreq.imr_interface, NULL);
2001                         if (ifp == NULL) {
2002                                 error = EADDRNOTAVAIL;
2003                                 splx(s);
2004                                 break;
2005                         }
2006                 }
2007                 /*
2008                  * Find the membership in the membership array.
2009                  */
2010                 for (i = 0; i < imo->imo_num_memberships; ++i) {
2011                         if ((ifp == NULL ||
2012                              imo->imo_membership[i]->inm_ifp == ifp) &&
2013                             imo->imo_membership[i]->inm_addr.s_addr ==
2014                             mreq.imr_multiaddr.s_addr)
2015                                 break;
2016                 }
2017                 if (i == imo->imo_num_memberships) {
2018                         error = EADDRNOTAVAIL;
2019                         splx(s);
2020                         break;
2021                 }
2022                 /*
2023                  * Give up the multicast address record to which the
2024                  * membership points.
2025                  */
2026                 in_delmulti(imo->imo_membership[i]);
2027                 /*
2028                  * Remove the gap in the membership array.
2029                  */
2030                 for (++i; i < imo->imo_num_memberships; ++i)
2031                         imo->imo_membership[i-1] = imo->imo_membership[i];
2032                 --imo->imo_num_memberships;
2033                 splx(s);
2034                 break;
2035
2036         default:
2037                 error = EOPNOTSUPP;
2038                 break;
2039         }
2040
2041         /*
2042          * If all options have default values, no need to keep the mbuf.
2043          */
2044         if (imo->imo_multicast_ifp == NULL &&
2045             imo->imo_multicast_vif == -1 &&
2046             imo->imo_multicast_ttl == IP_DEFAULT_MULTICAST_TTL &&
2047             imo->imo_multicast_loop == IP_DEFAULT_MULTICAST_LOOP &&
2048             imo->imo_num_memberships == 0) {
2049                 free(*imop, M_IPMOPTS);
2050                 *imop = NULL;
2051         }
2052
2053         return (error);
2054 }
2055
2056 /*
2057  * Return the IP multicast options in response to user getsockopt().
2058  */
2059 static int
2060 ip_getmoptions(struct sockopt *sopt, struct ip_moptions *imo)
2061 {
2062         struct in_addr addr;
2063         struct in_ifaddr *ia;
2064         int error, optval;
2065         u_char coptval;
2066
2067         error = 0;
2068         switch (sopt->sopt_name) {
2069         case IP_MULTICAST_VIF:
2070                 if (imo != NULL)
2071                         optval = imo->imo_multicast_vif;
2072                 else
2073                         optval = -1;
2074                 error = sooptcopyout(sopt, &optval, sizeof optval);
2075                 break;
2076
2077         case IP_MULTICAST_IF:
2078                 if (imo == NULL || imo->imo_multicast_ifp == NULL)
2079                         addr.s_addr = INADDR_ANY;
2080                 else if (imo->imo_multicast_addr.s_addr) {
2081                         /* return the value user has set */
2082                         addr = imo->imo_multicast_addr;
2083                 } else {
2084                         IFP_TO_IA(imo->imo_multicast_ifp, ia);
2085                         addr.s_addr = (ia == NULL) ? INADDR_ANY
2086                                 : IA_SIN(ia)->sin_addr.s_addr;
2087                 }
2088                 error = sooptcopyout(sopt, &addr, sizeof addr);
2089                 break;
2090
2091         case IP_MULTICAST_TTL:
2092                 if (imo == NULL)
2093                         optval = coptval = IP_DEFAULT_MULTICAST_TTL;
2094                 else
2095                         optval = coptval = imo->imo_multicast_ttl;
2096                 if (sopt->sopt_valsize == 1)
2097                         error = sooptcopyout(sopt, &coptval, 1);
2098                 else
2099                         error = sooptcopyout(sopt, &optval, sizeof optval);
2100                 break;
2101
2102         case IP_MULTICAST_LOOP:
2103                 if (imo == NULL)
2104                         optval = coptval = IP_DEFAULT_MULTICAST_LOOP;
2105                 else
2106                         optval = coptval = imo->imo_multicast_loop;
2107                 if (sopt->sopt_valsize == 1)
2108                         error = sooptcopyout(sopt, &coptval, 1);
2109                 else
2110                         error = sooptcopyout(sopt, &optval, sizeof optval);
2111                 break;
2112
2113         default:
2114                 error = ENOPROTOOPT;
2115                 break;
2116         }
2117         return (error);
2118 }
2119
2120 /*
2121  * Discard the IP multicast options.
2122  */
2123 void
2124 ip_freemoptions(struct ip_moptions *imo)
2125 {
2126         int i;
2127
2128         if (imo != NULL) {
2129                 for (i = 0; i < imo->imo_num_memberships; ++i)
2130                         in_delmulti(imo->imo_membership[i]);
2131                 free(imo, M_IPMOPTS);
2132         }
2133 }
2134
2135 /*
2136  * Routine called from ip_output() to loop back a copy of an IP multicast
2137  * packet to the input queue of a specified interface.  Note that this
2138  * calls the output routine of the loopback "driver", but with an interface
2139  * pointer that might NOT be a loopback interface -- evil, but easier than
2140  * replicating that code here.
2141  */
2142 static void
2143 ip_mloopback(struct ifnet *ifp, struct mbuf *m, struct sockaddr_in *dst,
2144              int hlen)
2145 {
2146         struct ip *ip;
2147         struct mbuf *copym;
2148
2149         copym = m_copypacket(m, MB_DONTWAIT);
2150         if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen))
2151                 copym = m_pullup(copym, hlen);
2152         if (copym != NULL) {
2153                 /*
2154                  * if the checksum hasn't been computed, mark it as valid
2155                  */
2156                 if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
2157                         in_delayed_cksum(copym);
2158                         copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
2159                         copym->m_pkthdr.csum_flags |=
2160                             CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
2161                         copym->m_pkthdr.csum_data = 0xffff;
2162                 }
2163                 /*
2164                  * We don't bother to fragment if the IP length is greater
2165                  * than the interface's MTU.  Can this possibly matter?
2166                  */
2167                 ip = mtod(copym, struct ip *);
2168                 ip->ip_len = htons(ip->ip_len);
2169                 ip->ip_off = htons(ip->ip_off);
2170                 ip->ip_sum = 0;
2171                 if (ip->ip_vhl == IP_VHL_BORING) {
2172                         ip->ip_sum = in_cksum_hdr(ip);
2173                 } else {
2174                         ip->ip_sum = in_cksum(copym, hlen);
2175                 }
2176                 /*
2177                  * NB:
2178                  * It's not clear whether there are any lingering
2179                  * reentrancy problems in other areas which might
2180                  * be exposed by using ip_input directly (in
2181                  * particular, everything which modifies the packet
2182                  * in-place).  Yet another option is using the
2183                  * protosw directly to deliver the looped back
2184                  * packet.  For the moment, we'll err on the side
2185                  * of safety by using if_simloop().
2186                  */
2187 #if 1 /* XXX */
2188                 if (dst->sin_family != AF_INET) {
2189                         printf("ip_mloopback: bad address family %d\n",
2190                                                 dst->sin_family);
2191                         dst->sin_family = AF_INET;
2192                 }
2193 #endif
2194
2195 #ifdef notdef
2196                 copym->m_pkthdr.rcvif = ifp;
2197                 ip_input(copym);
2198 #else
2199                 if_simloop(ifp, copym, dst->sin_family, 0);
2200 #endif
2201         }
2202 }