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 1.22 2004/10/15 22:59:10 hsu Exp $
  32  */
  33
  34 #define _IP_VHL
  35
  36 #include "opt_ipfw.h"
  37 #include "opt_ipdn.h"
  38 #include "opt_ipdivert.h"
  39 #include "opt_ipfilter.h"
  40 #include "opt_ipsec.h"
  41 #include "opt_random_ip_id.h"
  42 #include "opt_mbuf_stress_test.h"
  43
  44 #include <sys/param.h>
  45 #include <sys/systm.h>
  46 #include <sys/kernel.h>
  47 #include <sys/malloc.h>
  48 #include <sys/mbuf.h>
  49 #include <sys/protosw.h>
  50 #include <sys/socket.h>
  51 #include <sys/socketvar.h>
  52 #include <sys/proc.h>
  53 #include <sys/sysctl.h>
  54 #include <sys/in_cksum.h>
  55
  56 #include <net/if.h>
  57 #include <net/netisr.h>
  58 #include <net/pfil.h>
  59 #include <net/route.h>
  60
  61 #include <netinet/in.h>
  62 #include <netinet/in_systm.h>
  63 #include <netinet/ip.h>
  64 #include <netinet/in_pcb.h>
  65 #include <netinet/in_var.h>
  66 #include <netinet/ip_var.h>
  67
  68 static MALLOC_DEFINE(M_IPMOPTS, "ip_moptions", "internet multicast options");
  69
  70 #ifdef IPSEC
  71 #include <netinet6/ipsec.h>
  72 #include <netproto/key/key.h>
  73 #ifdef IPSEC_DEBUG
  74 #include <netproto/key/key_debug.h>
  75 #else
  76 #define KEYDEBUG(lev,arg)
  77 #endif
  78 #endif /*IPSEC*/
  79
  80 #ifdef FAST_IPSEC
  81 #include <netproto/ipsec/ipsec.h>
  82 #include <netproto/ipsec/xform.h>
  83 #include <netproto/ipsec/key.h>
  84 #endif /*FAST_IPSEC*/
  85
  86 #include <net/ipfw/ip_fw.h>
  87 #include <net/dummynet/ip_dummynet.h>
  88
  89 #define print_ip(x, a, y)        printf("%s %d.%d.%d.%d%s",\
  90                                 x, (ntohl(a.s_addr)>>24)&0xFF,\
  91                                   (ntohl(a.s_addr)>>16)&0xFF,\
  92                                   (ntohl(a.s_addr)>>8)&0xFF,\
  93                                   (ntohl(a.s_addr))&0xFF, y);
  94
  95 u_short ip_id;
  96
  97 #ifdef MBUF_STRESS_TEST
  98 int mbuf_frag_size = 0;
  99 SYSCTL_INT(_net_inet_ip, OID_AUTO, mbuf_frag_size, CTLFLAG_RW,
 100         &mbuf_frag_size, 0, "Fragment outgoing mbufs to this size");
 101 #endif
 102
 103 static struct mbuf *ip_insertoptions(struct mbuf *, struct mbuf *, int *);
 104 static struct ifnet *ip_multicast_if(struct in_addr *, int *);
 105 static void     ip_mloopback
 106         (struct ifnet *, struct mbuf *, struct sockaddr_in *, int);
 107 static int      ip_getmoptions
 108         (struct sockopt *, struct ip_moptions *);
 109 static int      ip_pcbopts(int, struct mbuf **, struct mbuf *);
 110 static int      ip_setmoptions
 111         (struct sockopt *, struct ip_moptions **);
 112
 113 int     ip_optcopy(struct ip *, struct ip *);
 114
 115
 116 extern  struct protosw inetsw[];
 117
 118 /*
 119  * IP output.  The packet in mbuf chain m contains a skeletal IP
 120  * header (with len, off, ttl, proto, tos, src, dst).
 121  * The mbuf chain containing the packet will be freed.
 122  * The mbuf opt, if present, will not be freed.
 123  */
 124 int
 125 ip_output(struct mbuf *m0, struct mbuf *opt, struct route *ro,
 126         int flags, struct ip_moptions *imo, struct inpcb *inp)
 127 {
 128         struct ip *ip;
 129         struct ifnet *ifp = NULL;       /* keep compiler happy */
 130         struct mbuf *m;
 131         int hlen = sizeof (struct ip);
 132         int len, off, error = 0;
 133         struct sockaddr_in *dst = NULL; /* keep compiler happy */
 134         struct in_ifaddr *ia = NULL;
 135         int isbroadcast, sw_csum;
 136         struct in_addr pkt_dst;
 137         struct route iproute;
 138 #ifdef IPSEC
 139         struct secpolicy *sp = NULL;
 140         struct socket *so = inp ? inp->inp_socket : NULL;
 141 #endif
 142 #ifdef FAST_IPSEC
 143         struct m_tag *mtag;
 144         struct secpolicy *sp = NULL;
 145         struct tdb_ident *tdbi;
 146         int s;
 147 #endif /* FAST_IPSEC */
 148         struct ip_fw_args args;
 149         int src_was_INADDR_ANY = 0;     /* as the name says... */
 150
 151         args.eh = NULL;
 152         args.rule = NULL;
 153         args.next_hop = NULL;
 154         args.divert_rule = 0;                   /* divert cookie */
 155
 156         /* Grab info from MT_TAG mbufs prepended to the chain. */
 157         for (; m0 && m0->m_type == MT_TAG; m0 = m0->m_next) {
 158                 switch(m0->_m_tag_id) {
 159                 default:
 160                         printf("ip_output: unrecognised MT_TAG tag %d\n",
 161                             m0->_m_tag_id);
 162                         break;
 163
 164                 case PACKET_TAG_DUMMYNET:
 165                         /*
 166                          * the packet was already tagged, so part of the
 167                          * processing was already done, and we need to go down.
 168                          * Get parameters from the header.
 169                          */
 170                         args.rule = ((struct dn_pkt *)m0)->rule;
 171                         opt = NULL ;
 172                         ro = & ( ((struct dn_pkt *)m0)->ro ) ;
 173                         imo = NULL ;
 174                         dst = ((struct dn_pkt *)m0)->dn_dst ;
 175                         ifp = ((struct dn_pkt *)m0)->ifp ;
 176                         flags = ((struct dn_pkt *)m0)->flags ;
 177                         break;
 178
 179                 case PACKET_TAG_DIVERT:
 180                         args.divert_rule = (int)m0->m_data & 0xffff;
 181                         break;
 182
 183                 case PACKET_TAG_IPFORWARD:
 184                         args.next_hop = (struct sockaddr_in *)m0->m_data;
 185                         break;
 186                 }
 187         }
 188         m = m0;
 189
 190         KASSERT(!m || (m->m_flags & M_PKTHDR) != 0, ("ip_output: no HDR"));
 191
 192         if (ro == NULL) {
 193                 ro = &iproute;
 194                 bzero(ro, sizeof(*ro));
 195         }
 196
 197         if (args.rule != NULL) {        /* dummynet already saw us */
 198                 ip = mtod(m, struct ip *);
 199                 hlen = IP_VHL_HL(ip->ip_vhl) << 2 ;
 200                 if (ro->ro_rt)
 201                         ia = ifatoia(ro->ro_rt->rt_ifa);
 202                 goto sendit;
 203         }
 204
 205         if (opt) {
 206                 len = 0;
 207                 m = ip_insertoptions(m, opt, &len);
 208                 if (len != 0)
 209                         hlen = len;
 210         }
 211         ip = mtod(m, struct ip *);
 212         pkt_dst = args.next_hop ? args.next_hop->sin_addr : ip->ip_dst;
 213
 214         /*
 215          * Fill in IP header.
 216          */
 217         if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) {
 218                 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, hlen >> 2);
 219                 ip->ip_off &= IP_DF;
 220 #ifdef RANDOM_IP_ID
 221                 ip->ip_id = ip_randomid();
 222 #else
 223                 ip->ip_id = htons(ip_id++);
 224 #endif
 225                 ipstat.ips_localout++;
 226         } else {
 227                 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 228         }
 229
 230         dst = (struct sockaddr_in *)&ro->ro_dst;
 231         /*
 232          * If there is a cached route,
 233          * check that it is to the same destination
 234          * and is still up.  If not, free it and try again.
 235          * The address family should also be checked in case of sharing the
 236          * cache with IPv6.
 237          */
 238         if (ro->ro_rt && ((ro->ro_rt->rt_flags & RTF_UP) == 0 ||
 239                           dst->sin_family != AF_INET ||
 240                           dst->sin_addr.s_addr != pkt_dst.s_addr)) {
 241                 RTFREE(ro->ro_rt);
 242                 ro->ro_rt = (struct rtentry *)0;
 243         }
 244         if (ro->ro_rt == 0) {
 245                 bzero(dst, sizeof(*dst));
 246                 dst->sin_family = AF_INET;
 247                 dst->sin_len = sizeof(*dst);
 248                 dst->sin_addr = pkt_dst;
 249         }
 250         /*
 251          * If routing to interface only,
 252          * short circuit routing lookup.
 253          */
 254         if (flags & IP_ROUTETOIF) {
 255                 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == 0 &&
 256                     (ia = ifatoia(ifa_ifwithnet(sintosa(dst)))) == 0) {
 257                         ipstat.ips_noroute++;
 258                         error = ENETUNREACH;
 259                         goto bad;
 260                 }
 261                 ifp = ia->ia_ifp;
 262                 ip->ip_ttl = 1;
 263                 isbroadcast = in_broadcast(dst->sin_addr, ifp);
 264         } else if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) &&
 265             imo != NULL && imo->imo_multicast_ifp != NULL) {
 266                 /*
 267                  * Bypass the normal routing lookup for multicast
 268                  * packets if the interface is specified.
 269                  */
 270                 ifp = imo->imo_multicast_ifp;
 271                 IFP_TO_IA(ifp, ia);
 272                 isbroadcast = 0;        /* fool gcc */
 273         } else {
 274                 /*
 275                  * If this is the case, we probably don't want to allocate
 276                  * a protocol-cloned route since we didn't get one from the
 277                  * ULP.  This lets TCP do its thing, while not burdening
 278                  * forwarding or ICMP with the overhead of cloning a route.
 279                  * Of course, we still want to do any cloning requested by
 280                  * the link layer, as this is probably required in all cases
 281                  * for correct operation (as it is for ARP).
 282                  */
 283                 if (ro->ro_rt == 0)
 284                         rtalloc_ign(ro, RTF_PRCLONING);
 285                 if (ro->ro_rt == 0) {
 286                         ipstat.ips_noroute++;
 287                         error = EHOSTUNREACH;
 288                         goto bad;
 289                 }
 290                 ia = ifatoia(ro->ro_rt->rt_ifa);
 291                 ifp = ro->ro_rt->rt_ifp;
 292                 ro->ro_rt->rt_use++;
 293                 if (ro->ro_rt->rt_flags & RTF_GATEWAY)
 294                         dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway;
 295                 if (ro->ro_rt->rt_flags & RTF_HOST)
 296                         isbroadcast = (ro->ro_rt->rt_flags & RTF_BROADCAST);
 297                 else
 298                         isbroadcast = in_broadcast(dst->sin_addr, ifp);
 299         }
 300         if (IN_MULTICAST(ntohl(pkt_dst.s_addr))) {
 301                 struct in_multi *inm;
 302
 303                 m->m_flags |= M_MCAST;
 304                 /*
 305                  * IP destination address is multicast.  Make sure "dst"
 306                  * still points to the address in "ro".  (It may have been
 307                  * changed to point to a gateway address, above.)
 308                  */
 309                 dst = (struct sockaddr_in *)&ro->ro_dst;
 310                 /*
 311                  * See if the caller provided any multicast options
 312                  */
 313                 if (imo != NULL) {
 314                         ip->ip_ttl = imo->imo_multicast_ttl;
 315                         if (imo->imo_multicast_vif != -1)
 316                                 ip->ip_src.s_addr =
 317                                     ip_mcast_src ?
 318                                     ip_mcast_src(imo->imo_multicast_vif) :
 319                                     INADDR_ANY;
 320                 } else
 321                         ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL;
 322                 /*
 323                  * Confirm that the outgoing interface supports multicast.
 324                  */
 325                 if ((imo == NULL) || (imo->imo_multicast_vif == -1)) {
 326                         if ((ifp->if_flags & IFF_MULTICAST) == 0) {
 327                                 ipstat.ips_noroute++;
 328                                 error = ENETUNREACH;
 329                                 goto bad;
 330                         }
 331                 }
 332                 /*
 333                  * If source address not specified yet, use address
 334                  * of outgoing interface.
 335                  */
 336                 if (ip->ip_src.s_addr == INADDR_ANY) {
 337                         /* Interface may have no addresses. */
 338                         if (ia != NULL)
 339                                 ip->ip_src = IA_SIN(ia)->sin_addr;
 340                 }
 341
 342                 IN_LOOKUP_MULTI(pkt_dst, ifp, inm);
 343                 if (inm != NULL &&
 344                    (imo == NULL || imo->imo_multicast_loop)) {
 345                         /*
 346                          * If we belong to the destination multicast group
 347                          * on the outgoing interface, and the caller did not
 348                          * forbid loopback, loop back a copy.
 349                          */
 350                         ip_mloopback(ifp, m, dst, hlen);
 351                 }
 352                 else {
 353                         /*
 354                          * If we are acting as a multicast router, perform
 355                          * multicast forwarding as if the packet had just
 356                          * arrived on the interface to which we are about
 357                          * to send.  The multicast forwarding function
 358                          * recursively calls this function, using the
 359                          * IP_FORWARDING flag to prevent infinite recursion.
 360                          *
 361                          * Multicasts that are looped back by ip_mloopback(),
 362                          * above, will be forwarded by the ip_input() routine,
 363                          * if necessary.
 364                          */
 365                         if (ip_mrouter && (flags & IP_FORWARDING) == 0) {
 366                                 /*
 367                                  * If rsvp daemon is not running, do not
 368                                  * set ip_moptions. This ensures that the packet
 369                                  * is multicast and not just sent down one link
 370                                  * as prescribed by rsvpd.
 371                                  */
 372                                 if (!rsvp_on)
 373                                         imo = NULL;
 374                                 if (ip_mforward &&
 375                                     ip_mforward(ip, ifp, m, imo) != 0) {
 376                                         m_freem(m);
 377                                         goto done;
 378                                 }
 379                         }
 380                 }
 381
 382                 /*
 383                  * Multicasts with a time-to-live of zero may be looped-
 384                  * back, above, but must not be transmitted on a network.
 385                  * Also, multicasts addressed to the loopback interface
 386                  * are not sent -- the above call to ip_mloopback() will
 387                  * loop back a copy if this host actually belongs to the
 388                  * destination group on the loopback interface.
 389                  */
 390                 if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) {
 391                         m_freem(m);
 392                         goto done;
 393                 }
 394
 395                 goto sendit;
 396         }
 397 #ifndef notdef
 398         /*
 399          * If the source address is not specified yet, use the address
 400          * of the outoing interface. In case, keep note we did that, so
 401          * if the the firewall changes the next-hop causing the output
 402          * interface to change, we can fix that.
 403          */
 404         if (ip->ip_src.s_addr == INADDR_ANY) {
 405                 /* Interface may have no addresses. */
 406                 if (ia != NULL) {
 407                         ip->ip_src = IA_SIN(ia)->sin_addr;
 408                         src_was_INADDR_ANY = 1;
 409                 }
 410         }
 411 #endif /* notdef */
 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
 423         /*
 424          * Look for broadcast address and
 425          * verify user is allowed to send
 426          * such a packet.
 427          */
 428         if (isbroadcast) {
 429                 if ((ifp->if_flags & IFF_BROADCAST) == 0) {
 430                         error = EADDRNOTAVAIL;
 431                         goto bad;
 432                 }
 433                 if ((flags & IP_ALLOWBROADCAST) == 0) {
 434                         error = EACCES;
 435                         goto bad;
 436                 }
 437                 /* don't allow broadcast messages to be fragmented */
 438                 if (ip->ip_len > ifp->if_mtu) {
 439                         error = EMSGSIZE;
 440                         goto bad;
 441                 }
 442                 m->m_flags |= M_BCAST;
 443         } else {
 444                 m->m_flags &= ~M_BCAST;
 445         }
 446
 447 sendit:
 448 #ifdef IPSEC
 449         /* get SP for this packet */
 450         if (so == NULL)
 451                 sp = ipsec4_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, flags, &error);
 452         else
 453                 sp = ipsec4_getpolicybysock(m, IPSEC_DIR_OUTBOUND, so, &error);
 454
 455         if (sp == NULL) {
 456                 ipsecstat.out_inval++;
 457                 goto bad;
 458         }
 459
 460         error = 0;
 461
 462         /* check policy */
 463         switch (sp->policy) {
 464         case IPSEC_POLICY_DISCARD:
 465                 /*
 466                  * This packet is just discarded.
 467                  */
 468                 ipsecstat.out_polvio++;
 469                 goto bad;
 470
 471         case IPSEC_POLICY_BYPASS:
 472         case IPSEC_POLICY_NONE:
 473                 /* no need to do IPsec. */
 474                 goto skip_ipsec;
 475
 476         case IPSEC_POLICY_IPSEC:
 477                 if (sp->req == NULL) {
 478                         /* acquire a policy */
 479                         error = key_spdacquire(sp);
 480                         goto bad;
 481                 }
 482                 break;
 483
 484         case IPSEC_POLICY_ENTRUST:
 485         default:
 486                 printf("ip_output: Invalid policy found. %d\n", sp->policy);
 487         }
 488     {
 489         struct ipsec_output_state state;
 490         bzero(&state, sizeof(state));
 491         state.m = m;
 492         if (flags & IP_ROUTETOIF) {
 493                 state.ro = &iproute;
 494                 bzero(&iproute, sizeof(iproute));
 495         } else
 496                 state.ro = ro;
 497         state.dst = (struct sockaddr *)dst;
 498
 499         ip->ip_sum = 0;
 500
 501         /*
 502          * XXX
 503          * delayed checksums are not currently compatible with IPsec
 504          */
 505         if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 506                 in_delayed_cksum(m);
 507                 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
 508         }
 509
 510         ip->ip_len = htons(ip->ip_len);
 511         ip->ip_off = htons(ip->ip_off);
 512
 513         error = ipsec4_output(&state, sp, flags);
 514
 515         m = state.m;
 516         if (flags & IP_ROUTETOIF) {
 517                 /*
 518                  * if we have tunnel mode SA, we may need to ignore
 519                  * IP_ROUTETOIF.
 520                  */
 521                 if (state.ro != &iproute || state.ro->ro_rt != NULL) {
 522                         flags &= ~IP_ROUTETOIF;
 523                         ro = state.ro;
 524                 }
 525         } else
 526                 ro = state.ro;
 527         dst = (struct sockaddr_in *)state.dst;
 528         if (error) {
 529                 /* mbuf is already reclaimed in ipsec4_output. */
 530                 m0 = NULL;
 531                 switch (error) {
 532                 case EHOSTUNREACH:
 533                 case ENETUNREACH:
 534                 case EMSGSIZE:
 535                 case ENOBUFS:
 536                 case ENOMEM:
 537                         break;
 538                 default:
 539                         printf("ip4_output (ipsec): error code %d\n", error);
 540                         /*fall through*/
 541                 case ENOENT:
 542                         /* don't show these error codes to the user */
 543                         error = 0;
 544                         break;
 545                 }
 546                 goto bad;
 547         }
 548     }
 549
 550         /* be sure to update variables that are affected by ipsec4_output() */
 551         ip = mtod(m, struct ip *);
 552 #ifdef _IP_VHL
 553         hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 554 #else
 555         hlen = ip->ip_hl << 2;
 556 #endif
 557         if (ro->ro_rt == NULL) {
 558                 if ((flags & IP_ROUTETOIF) == 0) {
 559                         printf("ip_output: "
 560                                 "can't update route after IPsec processing\n");
 561                         error = EHOSTUNREACH;   /*XXX*/
 562                         goto bad;
 563                 }
 564         } else {
 565                 ia = ifatoia(ro->ro_rt->rt_ifa);
 566                 ifp = ro->ro_rt->rt_ifp;
 567         }
 568
 569         /* make it flipped, again. */
 570         ip->ip_len = ntohs(ip->ip_len);
 571         ip->ip_off = ntohs(ip->ip_off);
 572 skip_ipsec:
 573 #endif /*IPSEC*/
 574 #ifdef FAST_IPSEC
 575         /*
 576          * Check the security policy (SP) for the packet and, if
 577          * required, do IPsec-related processing.  There are two
 578          * cases here; the first time a packet is sent through
 579          * it will be untagged and handled by ipsec4_checkpolicy.
 580          * If the packet is resubmitted to ip_output (e.g. after
 581          * AH, ESP, etc. processing), there will be a tag to bypass
 582          * the lookup and related policy checking.
 583          */
 584         mtag = m_tag_find(m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
 585         s = splnet();
 586         if (mtag != NULL) {
 587                 tdbi = (struct tdb_ident *)(mtag + 1);
 588                 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
 589                 if (sp == NULL)
 590                         error = -EINVAL;        /* force silent drop */
 591                 m_tag_delete(m, mtag);
 592         } else {
 593                 sp = ipsec4_checkpolicy(m, IPSEC_DIR_OUTBOUND, flags,
 594                                         &error, inp);
 595         }
 596         /*
 597          * There are four return cases:
 598          *    sp != NULL                    apply IPsec policy
 599          *    sp == NULL, error == 0        no IPsec handling needed
 600          *    sp == NULL, error == -EINVAL  discard packet w/o error
 601          *    sp == NULL, error != 0        discard packet, report error
 602          */
 603         if (sp != NULL) {
 604                 /* Loop detection, check if ipsec processing already done */
 605                 KASSERT(sp->req != NULL, ("ip_output: no ipsec request"));
 606                 for (mtag = m_tag_first(m); mtag != NULL;
 607                      mtag = m_tag_next(m, mtag)) {
 608                         if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
 609                                 continue;
 610                         if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
 611                             mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
 612                                 continue;
 613                         /*
 614                          * Check if policy has an SA associated with it.
 615                          * This can happen when an SP has yet to acquire
 616                          * an SA; e.g. on first reference.  If it occurs,
 617                          * then we let ipsec4_process_packet do its thing.
 618                          */
 619                         if (sp->req->sav == NULL)
 620                                 break;
 621                         tdbi = (struct tdb_ident *)(mtag + 1);
 622                         if (tdbi->spi == sp->req->sav->spi &&
 623                             tdbi->proto == sp->req->sav->sah->saidx.proto &&
 624                             bcmp(&tdbi->dst, &sp->req->sav->sah->saidx.dst,
 625                                  sizeof (union sockaddr_union)) == 0) {
 626                                 /*
 627                                  * No IPsec processing is needed, free
 628                                  * reference to SP.
 629                                  *
 630                                  * NB: null pointer to avoid free at
 631                                  *     done: below.
 632                                  */
 633                                 KEY_FREESP(&sp), sp = NULL;
 634                                 splx(s);
 635                                 goto spd_done;
 636                         }
 637                 }
 638
 639                 /*
 640                  * Do delayed checksums now because we send before
 641                  * this is done in the normal processing path.
 642                  */
 643                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 644                         in_delayed_cksum(m);
 645                         m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
 646                 }
 647
 648                 ip->ip_len = htons(ip->ip_len);
 649                 ip->ip_off = htons(ip->ip_off);
 650
 651                 /* NB: callee frees mbuf */
 652                 error = ipsec4_process_packet(m, sp->req, flags, 0);
 653                 /*
 654                  * Preserve KAME behaviour: ENOENT can be returned
 655                  * when an SA acquire is in progress.  Don't propagate
 656                  * this to user-level; it confuses applications.
 657                  *
 658                  * XXX this will go away when the SADB is redone.
 659                  */
 660                 if (error == ENOENT)
 661                         error = 0;
 662                 splx(s);
 663                 goto done;
 664         } else {
 665                 splx(s);
 666
 667                 if (error != 0) {
 668                         /*
 669                          * Hack: -EINVAL is used to signal that a packet
 670                          * should be silently discarded.  This is typically
 671                          * because we asked key management for an SA and
 672                          * it was delayed (e.g. kicked up to IKE).
 673                          */
 674                         if (error == -EINVAL)
 675                                 error = 0;
 676                         goto bad;
 677                 } else {
 678                         /* No IPsec processing for this packet. */
 679                 }
 680 #ifdef notyet
 681                 /*
 682                  * If deferred crypto processing is needed, check that
 683                  * the interface supports it.
 684                  */
 685                 mtag = m_tag_find(m, PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED, NULL);
 686                 if (mtag != NULL && (ifp->if_capenable & IFCAP_IPSEC) == 0) {
 687                         /* notify IPsec to do its own crypto */
 688                         ipsp_skipcrypto_unmark((struct tdb_ident *)(mtag + 1));
 689                         error = EHOSTUNREACH;
 690                         goto bad;
 691                 }
 692 #endif
 693         }
 694 spd_done:
 695 #endif /* FAST_IPSEC */
 696         /*
 697          * IpHack's section.
 698          * - Xlate: translate packet's addr/port (NAT).
 699          * - Firewall: deny/allow/etc.
 700          * - Wrap: fake packet's addr/port <unimpl.>
 701          * - Encapsulate: put it in another IP and send out. <unimp.>
 702          */
 703
 704         /*
 705          * Run through list of hooks for output packets.
 706          */
 707         if (pfil_has_hooks(&inet_pfil_hook)) {
 708                 error = pfil_run_hooks(&inet_pfil_hook, &m, ifp, PFIL_OUT);
 709                 if (error != 0 || m == NULL)
 710                         goto done;
 711                 ip = mtod(m, struct ip *);
 712         }
 713
 714         /*
 715          * Check with the firewall...
 716          * but not if we are already being fwd'd from a firewall.
 717          */
 718         if (fw_enable && IPFW_LOADED && !args.next_hop) {
 719                 struct sockaddr_in *old = dst;
 720
 721                 args.m = m;
 722                 args.next_hop = dst;
 723                 args.oif = ifp;
 724                 off = ip_fw_chk_ptr(&args);
 725                 m = args.m;
 726                 dst = args.next_hop;
 727
 728                 /*
 729                  * On return we must do the following:
 730                  * m == NULL    -> drop the pkt (old interface, deprecated)
 731                  * (off & IP_FW_PORT_DENY_FLAG) -> drop the pkt (new interface)
 732                  * 1<=off<= 0xffff              -> DIVERT
 733                  * (off & IP_FW_PORT_DYNT_FLAG) -> send to a DUMMYNET pipe
 734                  * (off & IP_FW_PORT_TEE_FLAG)  -> TEE the packet
 735                  * dst != old                   -> IPFIREWALL_FORWARD
 736                  * off==0, dst==old             -> accept
 737                  * If some of the above modules are not compiled in, then
 738                  * we should't have to check the corresponding condition
 739                  * (because the ipfw control socket should not accept
 740                  * unsupported rules), but better play safe and drop
 741                  * packets in case of doubt.
 742                  */
 743                 if ( (off & IP_FW_PORT_DENY_FLAG) || m == NULL) {
 744                         if (m)
 745                                 m_freem(m);
 746                         error = EACCES;
 747                         goto done;
 748                 }
 749                 ip = mtod(m, struct ip *);
 750                 if (off == 0 && dst == old)             /* common case */
 751                         goto pass;
 752                 if (DUMMYNET_LOADED && (off & IP_FW_PORT_DYNT_FLAG) != 0) {
 753                         /*
 754                          * pass the pkt to dummynet. Need to include
 755                          * pipe number, m, ifp, ro, dst because these are
 756                          * not recomputed in the next pass.
 757                          * All other parameters have been already used and
 758                          * so they are not needed anymore.
 759                          * XXX note: if the ifp or ro entry are deleted
 760                          * while a pkt is in dummynet, we are in trouble!
 761                          */
 762                         args.ro = ro;
 763                         args.dst = dst;
 764                         args.flags = flags;
 765
 766                         error = ip_dn_io_ptr(m, off & 0xffff, DN_TO_IP_OUT,
 767                                 &args);
 768                         goto done;
 769                 }
 770 #ifdef IPDIVERT
 771                 if (off != 0 && (off & IP_FW_PORT_DYNT_FLAG) == 0) {
 772                         struct mbuf *clone = NULL;
 773
 774                         /* Clone packet if we're doing a 'tee' */
 775                         if ((off & IP_FW_PORT_TEE_FLAG) != 0)
 776                                 clone = m_dup(m, MB_DONTWAIT);
 777
 778                         /*
 779                          * XXX
 780                          * delayed checksums are not currently compatible
 781                          * with divert sockets.
 782                          */
 783                         if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 784                                 in_delayed_cksum(m);
 785                                 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
 786                         }
 787
 788                         /* Restore packet header fields to original values */
 789                         ip->ip_len = htons(ip->ip_len);
 790                         ip->ip_off = htons(ip->ip_off);
 791
 792                         /* Deliver packet to divert input routine */
 793                         divert_packet(m, 0, off & 0xffff, args.divert_rule);
 794
 795                         /* If 'tee', continue with original packet */
 796                         if (clone != NULL) {
 797                                 m = clone;
 798                                 ip = mtod(m, struct ip *);
 799                                 goto pass;
 800                         }
 801                         goto done;
 802                 }
 803 #endif
 804
 805                 /* IPFIREWALL_FORWARD */
 806                 /*
 807                  * Check dst to make sure it is directly reachable on the
 808                  * interface we previously thought it was.
 809                  * If it isn't (which may be likely in some situations) we have
 810                  * to re-route it (ie, find a route for the next-hop and the
 811                  * associated interface) and set them here. This is nested
 812                  * forwarding which in most cases is undesirable, except where
 813                  * such control is nigh impossible. So we do it here.
 814                  * And I'm babbling.
 815                  */
 816                 if (off == 0 && old != dst) { /* FORWARD, dst has changed */
 817 #if 0
 818                         /*
 819                          * XXX To improve readability, this block should be
 820                          * changed into a function call as below:
 821                          */
 822                         error = ip_ipforward(&m, &dst, &ifp);
 823                         if (error)
 824                                 goto bad;
 825                         if (m == NULL) /* ip_input consumed the mbuf */
 826                                 goto done;
 827 #else
 828                         struct in_ifaddr *ia;
 829
 830                         /*
 831                          * XXX sro_fwd below is static, and a pointer
 832                          * to it gets passed to routines downstream.
 833                          * This could have surprisingly bad results in
 834                          * practice, because its content is overwritten
 835                          * by subsequent packets.
 836                          */
 837                         /* There must be a better way to do this next line... */
 838                         static struct route sro_fwd;
 839                         struct route *ro_fwd = &sro_fwd;
 840
 841 #if 0
 842                         print_ip("IPFIREWALL_FORWARD: New dst ip: ",
 843                             dst->sin_addr, "\n");
 844 #endif
 845
 846                         /*
 847                          * We need to figure out if we have been forwarded
 848                          * to a local socket. If so, then we should somehow
 849                          * "loop back" to ip_input, and get directed to the
 850                          * PCB as if we had received this packet. This is
 851                          * because it may be dificult to identify the packets
 852                          * you want to forward until they are being output
 853                          * and have selected an interface. (e.g. locally
 854                          * initiated packets) If we used the loopback inteface,
 855                          * we would not be able to control what happens
 856                          * as the packet runs through ip_input() as
 857                          * it is done through a ISR.
 858                          */
 859                         LIST_FOREACH(ia,
 860                             INADDR_HASH(dst->sin_addr.s_addr), ia_hash) {
 861                                 /*
 862                                  * If the addr to forward to is one
 863                                  * of ours, we pretend to
 864                                  * be the destination for this packet.
 865                                  */
 866                                 if (IA_SIN(ia)->sin_addr.s_addr ==
 867                                                  dst->sin_addr.s_addr)
 868                                         break;
 869                         }
 870                         if (ia) {       /* tell ip_input "dont filter" */
 871                                 struct m_hdr tag;
 872
 873                                 tag.mh_type = MT_TAG;
 874                                 tag.mh_flags = PACKET_TAG_IPFORWARD;
 875                                 tag.mh_data = (caddr_t)args.next_hop;
 876                                 tag.mh_next = m;
 877
 878                                 if (m->m_pkthdr.rcvif == NULL)
 879                                         m->m_pkthdr.rcvif = ifunit("lo0");
 880                                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 881                                         m->m_pkthdr.csum_flags |=
 882                                             CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
 883                                         m0->m_pkthdr.csum_data = 0xffff;
 884                                 }
 885                                 m->m_pkthdr.csum_flags |=
 886                                     CSUM_IP_CHECKED | CSUM_IP_VALID;
 887                                 ip->ip_len = htons(ip->ip_len);
 888                                 ip->ip_off = htons(ip->ip_off);
 889                                 ip_input((struct mbuf *)&tag);
 890                                 goto done;
 891                         }
 892                         /* Some of the logic for this was
 893                          * 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
 900                         ro_fwd->ro_rt = 0;
 901                         rtalloc_ign(ro_fwd, RTF_PRCLONING);
 902
 903                         if (ro_fwd->ro_rt == 0) {
 904                                 ipstat.ips_noroute++;
 905                                 error = EHOSTUNREACH;
 906                                 goto bad;
 907                         }
 908
 909                         ia = ifatoia(ro_fwd->ro_rt->rt_ifa);
 910                         ifp = ro_fwd->ro_rt->rt_ifp;
 911                         ro_fwd->ro_rt->rt_use++;
 912                         if (ro_fwd->ro_rt->rt_flags & RTF_GATEWAY)
 913                                 dst = (struct sockaddr_in *)
 914                                         ro_fwd->ro_rt->rt_gateway;
 915                         if (ro_fwd->ro_rt->rt_flags & RTF_HOST)
 916                                 isbroadcast =
 917                                     (ro_fwd->ro_rt->rt_flags & RTF_BROADCAST);
 918                         else
 919                                 isbroadcast = in_broadcast(dst->sin_addr, ifp);
 920                         if (ro->ro_rt)
 921                                 RTFREE(ro->ro_rt);
 922                         ro->ro_rt = ro_fwd->ro_rt;
 923                         dst = (struct sockaddr_in *)&ro_fwd->ro_dst;
 924
 925 #endif  /* ... block to be put into a function */
 926                         /*
 927                          * If we added a default src ip earlier,
 928                          * which would have been gotten from the-then
 929                          * interface, do it again, from the new one.
 930                          */
 931                         if (src_was_INADDR_ANY)
 932                                 ip->ip_src = IA_SIN(ia)->sin_addr;
 933                         goto pass ;
 934                 }
 935
 936                 /*
 937                  * if we get here, none of the above matches, and
 938                  * we have to drop the pkt
 939                  */
 940                 m_freem(m);
 941                 error = EACCES; /* not sure this is the right error msg */
 942                 goto done;
 943         }
 944
 945 pass:
 946         /* 127/8 must not appear on wire - RFC1122. */
 947         if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
 948             (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
 949                 if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
 950                         ipstat.ips_badaddr++;
 951                         error = EADDRNOTAVAIL;
 952                         goto bad;
 953                 }
 954         }
 955
 956         m->m_pkthdr.csum_flags |= CSUM_IP;
 957         sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_hwassist;
 958         if (sw_csum & CSUM_DELAY_DATA) {
 959                 in_delayed_cksum(m);
 960                 sw_csum &= ~CSUM_DELAY_DATA;
 961         }
 962         m->m_pkthdr.csum_flags &= ifp->if_hwassist;
 963
 964         /*
 965          * If small enough for interface, or the interface will take
 966          * care of the fragmentation for us, can just send directly.
 967          */
 968         if (ip->ip_len <= ifp->if_mtu || ((ifp->if_hwassist & CSUM_FRAGMENT) &&
 969             (ip->ip_off & IP_DF) == 0)) {
 970                 ip->ip_len = htons(ip->ip_len);
 971                 ip->ip_off = htons(ip->ip_off);
 972                 ip->ip_sum = 0;
 973                 if (sw_csum & CSUM_DELAY_IP) {
 974                         if (ip->ip_vhl == IP_VHL_BORING) {
 975                                 ip->ip_sum = in_cksum_hdr(ip);
 976                         } else {
 977                                 ip->ip_sum = in_cksum(m, hlen);
 978                         }
 979                 }
 980
 981                 /* Record statistics for this interface address. */
 982                 if (!(flags & IP_FORWARDING) && ia) {
 983                         ia->ia_ifa.if_opackets++;
 984                         ia->ia_ifa.if_obytes += m->m_pkthdr.len;
 985                 }
 986
 987 #ifdef IPSEC
 988                 /* clean ipsec history once it goes out of the node */
 989                 ipsec_delaux(m);
 990 #endif
 991
 992 #ifdef MBUF_STRESS_TEST
 993                 if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size) {
 994                         struct mbuf *m1, *m2;
 995                         int length, tmp;
 996
 997                         tmp = length = m->m_pkthdr.len;
 998
 999                         while ((length -= mbuf_frag_size) >= 1) {
1000                                 m1 = m_split(m, length, MB_DONTWAIT);
1001                                 if (m1 == NULL)
1002                                         break;
1003                                 m1->m_flags &= ~M_PKTHDR;
1004                                 m2 = m;
1005                                 while (m2->m_next != NULL)
1006                                         m2 = m2->m_next;
1007                                 m2->m_next = m1;
1008                         }
1009                         m->m_pkthdr.len = tmp;
1010                 }
1011 #endif
1012                 error = (*ifp->if_output)(ifp, m,
1013                                 (struct sockaddr *)dst, ro->ro_rt);
1014                 goto done;
1015         }
1016
1017         if (ip->ip_off & IP_DF) {
1018                 error = EMSGSIZE;
1019                 /*
1020                  * This case can happen if the user changed the MTU
1021                  * of an interface after enabling IP on it.  Because
1022                  * most netifs don't keep track of routes pointing to
1023                  * them, there is no way for one to update all its
1024                  * routes when the MTU is changed.
1025                  */
1026                 if ((ro->ro_rt->rt_flags & (RTF_UP | RTF_HOST)) &&
1027                     !(ro->ro_rt->rt_rmx.rmx_locks & RTV_MTU) &&
1028                     (ro->ro_rt->rt_rmx.rmx_mtu > ifp->if_mtu)) {
1029                         ro->ro_rt->rt_rmx.rmx_mtu = ifp->if_mtu;
1030                 }
1031                 ipstat.ips_cantfrag++;
1032                 goto bad;
1033         }
1034
1035         /*
1036          * Too large for interface; fragment if possible. If successful,
1037          * on return, m will point to a list of packets to be sent.
1038          */
1039         error = ip_fragment(ip, &m, ifp->if_mtu, ifp->if_hwassist, sw_csum);
1040         if (error)
1041                 goto bad;
1042         for (; m; m = m0) {
1043                 m0 = m->m_nextpkt;
1044                 m->m_nextpkt = 0;
1045 #ifdef IPSEC
1046                 /* clean ipsec history once it goes out of the node */
1047                 ipsec_delaux(m);
1048 #endif
1049                 if (error == 0) {
1050                         /* Record statistics for this interface address. */
1051                         if (ia != NULL) {
1052                                 ia->ia_ifa.if_opackets++;
1053                                 ia->ia_ifa.if_obytes += m->m_pkthdr.len;
1054                         }
1055
1056                         error = (*ifp->if_output)(ifp, m,
1057                             (struct sockaddr *)dst, ro->ro_rt);
1058                 } else
1059                         m_freem(m);
1060         }
1061
1062         if (error == 0)
1063                 ipstat.ips_fragmented++;
1064
1065 done:
1066         if (ro == &iproute && ro->ro_rt) {
1067                 RTFREE(ro->ro_rt);
1068                 ro->ro_rt = NULL;
1069         }
1070 #ifdef IPSEC
1071         if (sp != NULL) {
1072                 KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
1073                         printf("DP ip_output call free SP:%p\n", sp));
1074                 key_freesp(sp);
1075         }
1076 #endif
1077 #ifdef FAST_IPSEC
1078         if (sp != NULL)
1079                 KEY_FREESP(&sp);
1080 #endif
1081         return (error);
1082 bad:
1083         m_freem(m);
1084         goto done;
1085 }
1086
1087 /*
1088  * Create a chain of fragments which fit the given mtu. m_frag points to the
1089  * mbuf to be fragmented; on return it points to the chain with the fragments.
1090  * Return 0 if no error. If error, m_frag may contain a partially built
1091  * chain of fragments that should be freed by the caller.
1092  *
1093  * if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist)
1094  * sw_csum contains the delayed checksums flags (e.g., CSUM_DELAY_IP).
1095  */
1096 int
1097 ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu,
1098             u_long if_hwassist_flags, int sw_csum)
1099 {
1100         int error = 0;
1101         int hlen = IP_VHL_HL(ip->ip_vhl) << 2;
1102         int len = (mtu - hlen) & ~7;    /* size of payload in each fragment */
1103         int off;
1104         struct mbuf *m0 = *m_frag;      /* the original packet          */
1105         int firstlen;
1106         struct mbuf **mnext;
1107         int nfrags;
1108
1109         if (ip->ip_off & IP_DF) {       /* Fragmentation not allowed */
1110                 ipstat.ips_cantfrag++;
1111                 return EMSGSIZE;
1112         }
1113
1114         /*
1115          * Must be able to put at least 8 bytes per fragment.
1116          */
1117         if (len < 8)
1118                 return EMSGSIZE;
1119
1120         /*
1121          * If the interface will not calculate checksums on
1122          * fragmented packets, then do it here.
1123          */
1124         if (m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA &&
1125             (if_hwassist_flags & CSUM_IP_FRAGS) == 0) {
1126                 in_delayed_cksum(m0);
1127                 m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
1128         }
1129
1130         if (len > PAGE_SIZE) {
1131                 /*
1132                  * Fragment large datagrams such that each segment
1133                  * contains a multiple of PAGE_SIZE amount of data,
1134                  * plus headers. This enables a receiver to perform
1135                  * page-flipping zero-copy optimizations.
1136                  *
1137                  * XXX When does this help given that sender and receiver
1138                  * could have different page sizes, and also mtu could
1139                  * be less than the receiver's page size ?
1140                  */
1141                 int newlen;
1142                 struct mbuf *m;
1143
1144                 for (m = m0, off = 0; m && (off+m->m_len) <= mtu; m = m->m_next)
1145                         off += m->m_len;
1146
1147                 /*
1148                  * firstlen (off - hlen) must be aligned on an
1149                  * 8-byte boundary
1150                  */
1151                 if (off < hlen)
1152                         goto smart_frag_failure;
1153                 off = ((off - hlen) & ~7) + hlen;
1154                 newlen = (~PAGE_MASK) & mtu;
1155                 if ((newlen + sizeof (struct ip)) > mtu) {
1156                         /* we failed, go back the default */
1157 smart_frag_failure:
1158                         newlen = len;
1159                         off = hlen + len;
1160                 }
1161                 len = newlen;
1162
1163         } else {
1164                 off = hlen + len;
1165         }
1166
1167         firstlen = off - hlen;
1168         mnext = &m0->m_nextpkt;         /* pointer to next packet */
1169
1170         /*
1171          * Loop through length of segment after first fragment,
1172          * make new header and copy data of each part and link onto chain.
1173          * Here, m0 is the original packet, m is the fragment being created.
1174          * The fragments are linked off the m_nextpkt of the original
1175          * packet, which after processing serves as the first fragment.
1176          */
1177         for (nfrags = 1; off < ip->ip_len; off += len, nfrags++) {
1178                 struct ip *mhip;        /* ip header on the fragment */
1179                 struct mbuf *m;
1180                 int mhlen = sizeof (struct ip);
1181
1182                 MGETHDR(m, MB_DONTWAIT, MT_HEADER);
1183                 if (m == 0) {
1184                         error = ENOBUFS;
1185                         ipstat.ips_odropped++;
1186                         goto done;
1187                 }
1188                 m->m_flags |= (m0->m_flags & M_MCAST) | M_FRAG;
1189                 /*
1190                  * In the first mbuf, leave room for the link header, then
1191                  * copy the original IP header including options. The payload
1192                  * goes into an additional mbuf chain returned by m_copy().
1193                  */
1194                 m->m_data += max_linkhdr;
1195                 mhip = mtod(m, struct ip *);
1196                 *mhip = *ip;
1197                 if (hlen > sizeof (struct ip)) {
1198                         mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
1199                         mhip->ip_vhl = IP_MAKE_VHL(IPVERSION, mhlen >> 2);
1200                 }
1201                 m->m_len = mhlen;
1202                 /* XXX do we need to add ip->ip_off below ? */
1203                 mhip->ip_off = ((off - hlen) >> 3) + ip->ip_off;
1204                 if (off + len >= ip->ip_len) {  /* last fragment */
1205                         len = ip->ip_len - off;
1206                         m->m_flags |= M_LASTFRAG;
1207                 } else
1208                         mhip->ip_off |= IP_MF;
1209                 mhip->ip_len = htons((u_short)(len + mhlen));
1210                 m->m_next = m_copy(m0, off, len);
1211                 if (m->m_next == 0) {           /* copy failed */
1212                         m_free(m);
1213                         error = ENOBUFS;        /* ??? */
1214                         ipstat.ips_odropped++;
1215                         goto done;
1216                 }
1217                 m->m_pkthdr.len = mhlen + len;
1218                 m->m_pkthdr.rcvif = (struct ifnet *)0;
1219                 m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags;
1220                 mhip->ip_off = htons(mhip->ip_off);
1221                 mhip->ip_sum = 0;
1222                 if (sw_csum & CSUM_DELAY_IP)
1223                         mhip->ip_sum = in_cksum(m, mhlen);
1224                 *mnext = m;
1225                 mnext = &m->m_nextpkt;
1226         }
1227         ipstat.ips_ofragments += nfrags;
1228
1229         /* set first marker for fragment chain */
1230         m0->m_flags |= M_FIRSTFRAG | M_FRAG;
1231         m0->m_pkthdr.csum_data = nfrags;
1232
1233         /*
1234          * Update first fragment by trimming what's been copied out
1235          * and updating header.
1236          */
1237         m_adj(m0, hlen + firstlen - ip->ip_len);
1238         m0->m_pkthdr.len = hlen + firstlen;
1239         ip->ip_len = htons((u_short)m0->m_pkthdr.len);
1240         ip->ip_off |= IP_MF;
1241         ip->ip_off = htons(ip->ip_off);
1242         ip->ip_sum = 0;
1243         if (sw_csum & CSUM_DELAY_IP)
1244                 ip->ip_sum = in_cksum(m0, hlen);
1245
1246 done:
1247         *m_frag = m0;
1248         return error;
1249 }
1250
1251 void
1252 in_delayed_cksum(struct mbuf *m)
1253 {
1254         struct ip *ip;
1255         u_short csum, offset;
1256
1257         ip = mtod(m, struct ip *);
1258         offset = IP_VHL_HL(ip->ip_vhl) << 2 ;
1259         csum = in_cksum_skip(m, ip->ip_len, offset);
1260         if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0)
1261                 csum = 0xffff;
1262         offset += m->m_pkthdr.csum_data;        /* checksum offset */
1263
1264         if (offset + sizeof(u_short) > m->m_len) {
1265                 printf("delayed m_pullup, m->len: %d  off: %d  p: %d\n",
1266                     m->m_len, offset, ip->ip_p);
1267                 /*
1268                  * XXX
1269                  * this shouldn't happen, but if it does, the
1270                  * correct behavior may be to insert the checksum
1271                  * in the existing chain instead of rearranging it.
1272                  */
1273                 m = m_pullup(m, offset + sizeof(u_short));
1274         }
1275         *(u_short *)(m->m_data + offset) = csum;
1276 }
1277
1278 /*
1279  * Insert IP options into preformed packet.
1280  * Adjust IP destination as required for IP source routing,
1281  * as indicated by a non-zero in_addr at the start of the options.
1282  *
1283  * XXX This routine assumes that the packet has no options in place.
1284  */
1285 static struct mbuf *
1286 ip_insertoptions(m, opt, phlen)
1287         struct mbuf *m;
1288         struct mbuf *opt;
1289         int *phlen;
1290 {
1291         struct ipoption *p = mtod(opt, struct ipoption *);
1292         struct mbuf *n;
1293         struct ip *ip = mtod(m, struct ip *);
1294         unsigned optlen;
1295
1296         optlen = opt->m_len - sizeof(p->ipopt_dst);
1297         if (optlen + (u_short)ip->ip_len > IP_MAXPACKET) {
1298                 *phlen = 0;
1299                 return (m);             /* XXX should fail */
1300         }
1301         if (p->ipopt_dst.s_addr)
1302                 ip->ip_dst = p->ipopt_dst;
1303         if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) {
1304                 MGETHDR(n, MB_DONTWAIT, MT_HEADER);
1305                 if (n == 0) {
1306                         *phlen = 0;
1307                         return (m);
1308                 }
1309                 n->m_pkthdr.rcvif = (struct ifnet *)0;
1310                 n->m_pkthdr.len = m->m_pkthdr.len + optlen;
1311                 m->m_len -= sizeof(struct ip);
1312                 m->m_data += sizeof(struct ip);
1313                 n->m_next = m;
1314                 m = n;
1315                 m->m_len = optlen + sizeof(struct ip);
1316                 m->m_data += max_linkhdr;
1317                 (void)memcpy(mtod(m, void *), ip, sizeof(struct ip));
1318         } else {
1319                 m->m_data -= optlen;
1320                 m->m_len += optlen;
1321                 m->m_pkthdr.len += optlen;
1322                 ovbcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
1323         }
1324         ip = mtod(m, struct ip *);
1325         bcopy(p->ipopt_list, ip + 1, optlen);
1326         *phlen = sizeof(struct ip) + optlen;
1327         ip->ip_vhl = IP_MAKE_VHL(IPVERSION, *phlen >> 2);
1328         ip->ip_len += optlen;
1329         return (m);
1330 }
1331
1332 /*
1333  * Copy options from ip to jp,
1334  * omitting those not copied during fragmentation.
1335  */
1336 int
1337 ip_optcopy(ip, jp)
1338         struct ip *ip, *jp;
1339 {
1340         u_char *cp, *dp;
1341         int opt, optlen, cnt;
1342
1343         cp = (u_char *)(ip + 1);
1344         dp = (u_char *)(jp + 1);
1345         cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip);
1346         for (; cnt > 0; cnt -= optlen, cp += optlen) {
1347                 opt = cp[0];
1348                 if (opt == IPOPT_EOL)
1349                         break;
1350                 if (opt == IPOPT_NOP) {
1351                         /* Preserve for IP mcast tunnel's LSRR alignment. */
1352                         *dp++ = IPOPT_NOP;
1353                         optlen = 1;
1354                         continue;
1355                 }
1356
1357                 KASSERT(cnt >= IPOPT_OLEN + sizeof(*cp),
1358                     ("ip_optcopy: malformed ipv4 option"));
1359                 optlen = cp[IPOPT_OLEN];
1360                 KASSERT(optlen >= IPOPT_OLEN + sizeof(*cp) && optlen <= cnt,
1361                     ("ip_optcopy: malformed ipv4 option"));
1362
1363                 /* bogus lengths should have been caught by ip_dooptions */
1364                 if (optlen > cnt)
1365                         optlen = cnt;
1366                 if (IPOPT_COPIED(opt)) {
1367                         bcopy(cp, dp, optlen);
1368                         dp += optlen;
1369                 }
1370         }
1371         for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++)
1372                 *dp++ = IPOPT_EOL;
1373         return (optlen);
1374 }
1375
1376 /*
1377  * IP socket option processing.
1378  */
1379 int
1380 ip_ctloutput(so, sopt)
1381         struct socket *so;
1382         struct sockopt *sopt;
1383 {
1384         struct  inpcb *inp = sotoinpcb(so);
1385         int     error, optval;
1386
1387         error = optval = 0;
1388         if (sopt->sopt_level != IPPROTO_IP) {
1389                 return (EINVAL);
1390         }
1391
1392         switch (sopt->sopt_dir) {
1393         case SOPT_SET:
1394                 switch (sopt->sopt_name) {
1395                 case IP_OPTIONS:
1396 #ifdef notyet
1397                 case IP_RETOPTS:
1398 #endif
1399                 {
1400                         struct mbuf *m;
1401                         if (sopt->sopt_valsize > MLEN) {
1402                                 error = EMSGSIZE;
1403                                 break;
1404                         }
1405                         MGET(m, sopt->sopt_td ? MB_WAIT : MB_DONTWAIT, MT_HEADER);
1406                         if (m == 0) {
1407                                 error = ENOBUFS;
1408                                 break;
1409                         }
1410                         m->m_len = sopt->sopt_valsize;
1411                         error = sooptcopyin(sopt, mtod(m, char *), m->m_len,
1412                                             m->m_len);
1413
1414                         return (ip_pcbopts(sopt->sopt_name, &inp->inp_options,
1415                                            m));
1416                 }
1417
1418                 case IP_TOS:
1419                 case IP_TTL:
1420                 case IP_RECVOPTS:
1421                 case IP_RECVRETOPTS:
1422                 case IP_RECVDSTADDR:
1423                 case IP_RECVIF:
1424                 case IP_FAITH:
1425                         error = sooptcopyin(sopt, &optval, sizeof optval,
1426                                             sizeof optval);
1427                         if (error)
1428                                 break;
1429
1430                         switch (sopt->sopt_name) {
1431                         case IP_TOS:
1432                                 inp->inp_ip_tos = optval;
1433                                 break;
1434
1435                         case IP_TTL:
1436                                 inp->inp_ip_ttl = optval;
1437                                 break;
1438 #define OPTSET(bit) \
1439         if (optval) \
1440                 inp->inp_flags |= bit; \
1441         else \
1442                 inp->inp_flags &= ~bit;
1443
1444                         case IP_RECVOPTS:
1445                                 OPTSET(INP_RECVOPTS);
1446                                 break;
1447
1448                         case IP_RECVRETOPTS:
1449                                 OPTSET(INP_RECVRETOPTS);
1450                                 break;
1451
1452                         case IP_RECVDSTADDR:
1453                                 OPTSET(INP_RECVDSTADDR);
1454                                 break;
1455
1456                         case IP_RECVIF:
1457                                 OPTSET(INP_RECVIF);
1458                                 break;
1459
1460                         case IP_FAITH:
1461                                 OPTSET(INP_FAITH);
1462                                 break;
1463                         }
1464                         break;
1465 #undef OPTSET
1466
1467                 case IP_MULTICAST_IF:
1468                 case IP_MULTICAST_VIF:
1469                 case IP_MULTICAST_TTL:
1470                 case IP_MULTICAST_LOOP:
1471                 case IP_ADD_MEMBERSHIP:
1472                 case IP_DROP_MEMBERSHIP:
1473                         error = ip_setmoptions(sopt, &inp->inp_moptions);
1474                         break;
1475
1476                 case IP_PORTRANGE:
1477                         error = sooptcopyin(sopt, &optval, sizeof optval,
1478                                             sizeof optval);
1479                         if (error)
1480                                 break;
1481
1482                         switch (optval) {
1483                         case IP_PORTRANGE_DEFAULT:
1484                                 inp->inp_flags &= ~(INP_LOWPORT);
1485                                 inp->inp_flags &= ~(INP_HIGHPORT);
1486                                 break;
1487
1488                         case IP_PORTRANGE_HIGH:
1489                                 inp->inp_flags &= ~(INP_LOWPORT);
1490                                 inp->inp_flags |= INP_HIGHPORT;
1491                                 break;
1492
1493                         case IP_PORTRANGE_LOW:
1494                                 inp->inp_flags &= ~(INP_HIGHPORT);
1495                                 inp->inp_flags |= INP_LOWPORT;
1496                                 break;
1497
1498                         default:
1499                                 error = EINVAL;
1500                                 break;
1501                         }
1502                         break;
1503
1504 #if defined(IPSEC) || defined(FAST_IPSEC)
1505                 case IP_IPSEC_POLICY:
1506                 {
1507                         caddr_t req;
1508                         size_t len = 0;
1509                         int priv;
1510                         struct mbuf *m;
1511                         int optname;
1512
1513                         if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */
1514                                 break;
1515                         if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */
1516                                 break;
1517                         priv = (sopt->sopt_td != NULL &&
1518                                 suser(sopt->sopt_td) != 0) ? 0 : 1;
1519                         req = mtod(m, caddr_t);
1520                         len = m->m_len;
1521                         optname = sopt->sopt_name;
1522                         error = ipsec4_set_policy(inp, optname, req, len, priv);
1523                         m_freem(m);
1524                         break;
1525                 }
1526 #endif /*IPSEC*/
1527
1528                 default:
1529                         error = ENOPROTOOPT;
1530                         break;
1531                 }
1532                 break;
1533
1534         case SOPT_GET:
1535                 switch (sopt->sopt_name) {
1536                 case IP_OPTIONS:
1537                 case IP_RETOPTS:
1538                         if (inp->inp_options)
1539                                 error = sooptcopyout(sopt,
1540                                                      mtod(inp->inp_options,
1541                                                           char *),
1542                                                      inp->inp_options->m_len);
1543                         else
1544                                 sopt->sopt_valsize = 0;
1545                         break;
1546
1547                 case IP_TOS:
1548                 case IP_TTL:
1549                 case IP_RECVOPTS:
1550                 case IP_RECVRETOPTS:
1551                 case IP_RECVDSTADDR:
1552                 case IP_RECVIF:
1553                 case IP_PORTRANGE:
1554                 case IP_FAITH:
1555                         switch (sopt->sopt_name) {
1556
1557                         case IP_TOS:
1558                                 optval = inp->inp_ip_tos;
1559                                 break;
1560
1561                         case IP_TTL:
1562                                 optval = inp->inp_ip_ttl;
1563                                 break;
1564
1565 #define OPTBIT(bit)     (inp->inp_flags & bit ? 1 : 0)
1566
1567                         case IP_RECVOPTS:
1568                                 optval = OPTBIT(INP_RECVOPTS);
1569                                 break;
1570
1571                         case IP_RECVRETOPTS:
1572                                 optval = OPTBIT(INP_RECVRETOPTS);
1573                                 break;
1574
1575                         case IP_RECVDSTADDR:
1576                                 optval = OPTBIT(INP_RECVDSTADDR);
1577                                 break;
1578
1579                         case IP_RECVIF:
1580                                 optval = OPTBIT(INP_RECVIF);
1581                                 break;
1582
1583                         case IP_PORTRANGE:
1584                                 if (inp->inp_flags & INP_HIGHPORT)
1585                                         optval = IP_PORTRANGE_HIGH;
1586                                 else if (inp->inp_flags & INP_LOWPORT)
1587                                         optval = IP_PORTRANGE_LOW;
1588                                 else
1589                                         optval = 0;
1590                                 break;
1591
1592                         case IP_FAITH:
1593                                 optval = OPTBIT(INP_FAITH);
1594                                 break;
1595                         }
1596                         error = sooptcopyout(sopt, &optval, sizeof optval);
1597                         break;
1598
1599                 case IP_MULTICAST_IF:
1600                 case IP_MULTICAST_VIF:
1601                 case IP_MULTICAST_TTL:
1602                 case IP_MULTICAST_LOOP:
1603                 case IP_ADD_MEMBERSHIP:
1604                 case IP_DROP_MEMBERSHIP:
1605                         error = ip_getmoptions(sopt, inp->inp_moptions);
1606                         break;
1607
1608 #if defined(IPSEC) || defined(FAST_IPSEC)
1609                 case IP_IPSEC_POLICY:
1610                 {
1611                         struct mbuf *m = NULL;
1612                         caddr_t req = NULL;
1613                         size_t len = 0;
1614
1615                         if (m != 0) {
1616                                 req = mtod(m, caddr_t);
1617                                 len = m->m_len;
1618                         }
1619                         error = ipsec4_get_policy(sotoinpcb(so), req, len, &m);
1620                         if (error == 0)
1621                                 error = soopt_mcopyout(sopt, m); /* XXX */
1622                         if (error == 0)
1623                                 m_freem(m);
1624                         break;
1625                 }
1626 #endif /*IPSEC*/
1627
1628                 default:
1629                         error = ENOPROTOOPT;
1630                         break;
1631                 }
1632                 break;
1633         }
1634         return (error);
1635 }
1636
1637 /*
1638  * Set up IP options in pcb for insertion in output packets.
1639  * Store in mbuf with pointer in pcbopt, adding pseudo-option
1640  * with destination address if source routed.
1641  */
1642 static int
1643 ip_pcbopts(optname, pcbopt, m)
1644         int optname;
1645         struct mbuf **pcbopt;
1646         struct mbuf *m;
1647 {
1648         int cnt, optlen;
1649         u_char *cp;
1650         u_char opt;
1651
1652         /* turn off any old options */
1653         if (*pcbopt)
1654                 (void)m_free(*pcbopt);
1655         *pcbopt = 0;
1656         if (m == (struct mbuf *)0 || m->m_len == 0) {
1657                 /*
1658                  * Only turning off any previous options.
1659                  */
1660                 if (m)
1661                         (void)m_free(m);
1662                 return (0);
1663         }
1664
1665         if (m->m_len % sizeof(int32_t))
1666                 goto bad;
1667         /*
1668          * IP first-hop destination address will be stored before
1669          * actual options; move other options back
1670          * and clear it when none present.
1671          */
1672         if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN])
1673                 goto bad;
1674         cnt = m->m_len;
1675         m->m_len += sizeof(struct in_addr);
1676         cp = mtod(m, u_char *) + sizeof(struct in_addr);
1677         ovbcopy(mtod(m, caddr_t), (caddr_t)cp, (unsigned)cnt);
1678         bzero(mtod(m, caddr_t), sizeof(struct in_addr));
1679
1680         for (; cnt > 0; cnt -= optlen, cp += optlen) {
1681                 opt = cp[IPOPT_OPTVAL];
1682                 if (opt == IPOPT_EOL)
1683                         break;
1684                 if (opt == IPOPT_NOP)
1685                         optlen = 1;
1686                 else {
1687                         if (cnt < IPOPT_OLEN + sizeof(*cp))
1688                                 goto bad;
1689                         optlen = cp[IPOPT_OLEN];
1690                         if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt)
1691                                 goto bad;
1692                 }
1693                 switch (opt) {
1694
1695                 default:
1696                         break;
1697
1698                 case IPOPT_LSRR:
1699                 case IPOPT_SSRR:
1700                         /*
1701                          * user process specifies route as:
1702                          *      ->A->B->C->D
1703                          * D must be our final destination (but we can't
1704                          * check that since we may not have connected yet).
1705                          * A is first hop destination, which doesn't appear in
1706                          * actual IP option, but is stored before the options.
1707                          */
1708                         if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr))
1709                                 goto bad;
1710                         m->m_len -= sizeof(struct in_addr);
1711                         cnt -= sizeof(struct in_addr);
1712                         optlen -= sizeof(struct in_addr);
1713                         cp[IPOPT_OLEN] = optlen;
1714                         /*
1715                          * Move first hop before start of options.
1716                          */
1717                         bcopy((caddr_t)&cp[IPOPT_OFFSET+1], mtod(m, caddr_t),
1718                             sizeof(struct in_addr));
1719                         /*
1720                          * Then copy rest of options back
1721                          * to close up the deleted entry.
1722                          */
1723                         ovbcopy((caddr_t)(&cp[IPOPT_OFFSET+1] +
1724                             sizeof(struct in_addr)),
1725                             &cp[IPOPT_OFFSET+1],
1726                             (unsigned)cnt - (IPOPT_MINOFF - 1));
1727                         break;
1728                 }
1729         }
1730         if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr))
1731                 goto bad;
1732         *pcbopt = m;
1733         return (0);
1734
1735 bad:
1736         (void)m_free(m);
1737         return (EINVAL);
1738 }
1739
1740 /*
1741  * XXX
1742  * The whole multicast option thing needs to be re-thought.
1743  * Several of these options are equally applicable to non-multicast
1744  * transmission, and one (IP_MULTICAST_TTL) totally duplicates a
1745  * standard option (IP_TTL).
1746  */
1747
1748 /*
1749  * following RFC1724 section 3.3, 0.0.0.0/8 is interpreted as interface index.
1750  */
1751 static struct ifnet *
1752 ip_multicast_if(a, ifindexp)
1753         struct in_addr *a;
1754         int *ifindexp;
1755 {
1756         int ifindex;
1757         struct ifnet *ifp;
1758
1759         if (ifindexp)
1760                 *ifindexp = 0;
1761         if (ntohl(a->s_addr) >> 24 == 0) {
1762                 ifindex = ntohl(a->s_addr) & 0xffffff;
1763                 if (ifindex < 0 || if_index < ifindex)
1764                         return NULL;
1765                 ifp = ifindex2ifnet[ifindex];
1766                 if (ifindexp)
1767                         *ifindexp = ifindex;
1768         } else {
1769                 INADDR_TO_IFP(*a, ifp);
1770         }
1771         return ifp;
1772 }
1773
1774 /*
1775  * Set the IP multicast options in response to user setsockopt().
1776  */
1777 static int
1778 ip_setmoptions(sopt, imop)
1779         struct sockopt *sopt;
1780         struct ip_moptions **imop;
1781 {
1782         int error = 0;
1783         int i;
1784         struct in_addr addr;
1785         struct ip_mreq mreq;
1786         struct ifnet *ifp;
1787         struct ip_moptions *imo = *imop;
1788         struct route ro;
1789         struct sockaddr_in *dst;
1790         int ifindex;
1791         int s;
1792
1793         if (imo == NULL) {
1794                 /*
1795                  * No multicast option buffer attached to the pcb;
1796                  * allocate one and initialize to default values.
1797                  */
1798                 imo = (struct ip_moptions*)malloc(sizeof(*imo), M_IPMOPTS,
1799                     M_WAITOK);
1800
1801                 if (imo == NULL)
1802                         return (ENOBUFS);
1803                 *imop = imo;
1804                 imo->imo_multicast_ifp = NULL;
1805                 imo->imo_multicast_addr.s_addr = INADDR_ANY;
1806                 imo->imo_multicast_vif = -1;
1807                 imo->imo_multicast_ttl = IP_DEFAULT_MULTICAST_TTL;
1808                 imo->imo_multicast_loop = IP_DEFAULT_MULTICAST_LOOP;
1809                 imo->imo_num_memberships = 0;
1810         }
1811
1812         switch (sopt->sopt_name) {
1813         /* store an index number for the vif you wanna use in the send */
1814         case IP_MULTICAST_VIF:
1815                 if (legal_vif_num == 0) {
1816                         error = EOPNOTSUPP;
1817                         break;
1818                 }
1819                 error = sooptcopyin(sopt, &i, sizeof i, sizeof i);
1820                 if (error)
1821                         break;
1822                 if (!legal_vif_num(i) && (i != -1)) {
1823                         error = EINVAL;
1824                         break;
1825                 }
1826                 imo->imo_multicast_vif = i;
1827                 break;
1828
1829         case IP_MULTICAST_IF:
1830                 /*
1831                  * Select the interface for outgoing multicast packets.
1832                  */
1833                 error = sooptcopyin(sopt, &addr, sizeof addr, sizeof addr);
1834                 if (error)
1835                         break;
1836                 /*
1837                  * INADDR_ANY is used to remove a previous selection.
1838                  * When no interface is selected, a default one is
1839                  * chosen every time a multicast packet is sent.
1840                  */
1841                 if (addr.s_addr == INADDR_ANY) {
1842                         imo->imo_multicast_ifp = NULL;
1843                         break;
1844                 }
1845                 /*
1846                  * The selected interface is identified by its local
1847                  * IP address.  Find the interface and confirm that
1848                  * it supports multicasting.
1849                  */
1850                 s = splimp();
1851                 ifp = ip_multicast_if(&addr, &ifindex);
1852                 if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) {
1853                         splx(s);
1854                         error = EADDRNOTAVAIL;
1855                         break;
1856                 }
1857                 imo->imo_multicast_ifp = ifp;
1858                 if (ifindex)
1859                         imo->imo_multicast_addr = addr;
1860                 else
1861                         imo->imo_multicast_addr.s_addr = INADDR_ANY;
1862                 splx(s);
1863                 break;
1864
1865         case IP_MULTICAST_TTL:
1866                 /*
1867                  * Set the IP time-to-live for outgoing multicast packets.
1868                  * The original multicast API required a char argument,
1869                  * which is inconsistent with the rest of the socket API.
1870                  * We allow either a char or an int.
1871                  */
1872                 if (sopt->sopt_valsize == 1) {
1873                         u_char ttl;
1874                         error = sooptcopyin(sopt, &ttl, 1, 1);
1875                         if (error)
1876                                 break;
1877                         imo->imo_multicast_ttl = ttl;
1878                 } else {
1879                         u_int ttl;
1880                         error = sooptcopyin(sopt, &ttl, sizeof ttl,
1881                                             sizeof ttl);
1882                         if (error)
1883                                 break;
1884                         if (ttl > 255)
1885                                 error = EINVAL;
1886                         else
1887                                 imo->imo_multicast_ttl = ttl;
1888                 }
1889                 break;
1890
1891         case IP_MULTICAST_LOOP:
1892                 /*
1893                  * Set the loopback flag for outgoing multicast packets.
1894                  * Must be zero or one.  The original multicast API required a
1895                  * char argument, which is inconsistent with the rest
1896                  * of the socket API.  We allow either a char or an int.
1897                  */
1898                 if (sopt->sopt_valsize == 1) {
1899                         u_char loop;
1900                         error = sooptcopyin(sopt, &loop, 1, 1);
1901                         if (error)
1902                                 break;
1903                         imo->imo_multicast_loop = !!loop;
1904                 } else {
1905                         u_int loop;
1906                         error = sooptcopyin(sopt, &loop, sizeof loop,
1907                                             sizeof loop);
1908                         if (error)
1909                                 break;
1910                         imo->imo_multicast_loop = !!loop;
1911                 }
1912                 break;
1913
1914         case IP_ADD_MEMBERSHIP:
1915                 /*
1916                  * Add a multicast group membership.
1917                  * Group must be a valid IP multicast address.
1918                  */
1919                 error = sooptcopyin(sopt, &mreq, sizeof mreq, sizeof mreq);
1920                 if (error)
1921                         break;
1922
1923                 if (!IN_MULTICAST(ntohl(mreq.imr_multiaddr.s_addr))) {
1924                         error = EINVAL;
1925                         break;
1926                 }
1927                 s = splimp();
1928                 /*
1929                  * If no interface address was provided, use the interface of
1930                  * the route to the given multicast address.
1931                  */
1932                 if (mreq.imr_interface.s_addr == INADDR_ANY) {
1933                         bzero((caddr_t)&ro, sizeof(ro));
1934                         dst = (struct sockaddr_in *)&ro.ro_dst;
1935                         dst->sin_len = sizeof(*dst);
1936                         dst->sin_family = AF_INET;
1937                         dst->sin_addr = mreq.imr_multiaddr;
1938                         rtalloc(&ro);
1939                         if (ro.ro_rt == NULL) {
1940                                 error = EADDRNOTAVAIL;
1941                                 splx(s);
1942                                 break;
1943                         }
1944                         ifp = ro.ro_rt->rt_ifp;
1945                         rtfree(ro.ro_rt);
1946                 }
1947                 else {
1948                         ifp = ip_multicast_if(&mreq.imr_interface, NULL);
1949                 }
1950
1951                 /*
1952                  * See if we found an interface, and confirm that it
1953                  * supports multicast.
1954                  */
1955                 if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) {
1956                         error = EADDRNOTAVAIL;
1957                         splx(s);
1958                         break;
1959                 }
1960                 /*
1961                  * See if the membership already exists or if all the
1962                  * membership slots are full.
1963                  */
1964                 for (i = 0; i < imo->imo_num_memberships; ++i) {
1965                         if (imo->imo_membership[i]->inm_ifp == ifp &&
1966                             imo->imo_membership[i]->inm_addr.s_addr
1967                                                 == mreq.imr_multiaddr.s_addr)
1968                                 break;
1969                 }
1970                 if (i < imo->imo_num_memberships) {
1971                         error = EADDRINUSE;
1972                         splx(s);
1973                         break;
1974                 }
1975                 if (i == IP_MAX_MEMBERSHIPS) {
1976                         error = ETOOMANYREFS;
1977                         splx(s);
1978                         break;
1979                 }
1980                 /*
1981                  * Everything looks good; add a new record to the multicast
1982                  * address list for the given interface.
1983                  */
1984                 if ((imo->imo_membership[i] =
1985                     in_addmulti(&mreq.imr_multiaddr, ifp)) == NULL) {
1986                         error = ENOBUFS;
1987                         splx(s);
1988                         break;
1989                 }
1990                 ++imo->imo_num_memberships;
1991                 splx(s);
1992                 break;
1993
1994         case IP_DROP_MEMBERSHIP:
1995                 /*
1996                  * Drop a multicast group membership.
1997                  * Group must be a valid IP multicast address.
1998                  */
1999                 error = sooptcopyin(sopt, &mreq, sizeof mreq, sizeof mreq);
2000                 if (error)
2001                         break;
2002
2003                 if (!IN_MULTICAST(ntohl(mreq.imr_multiaddr.s_addr))) {
2004                         error = EINVAL;
2005                         break;
2006                 }
2007
2008                 s = splimp();
2009                 /*
2010                  * If an interface address was specified, get a pointer
2011                  * to its ifnet structure.
2012                  */
2013                 if (mreq.imr_interface.s_addr == INADDR_ANY)
2014                         ifp = NULL;
2015                 else {
2016                         ifp = ip_multicast_if(&mreq.imr_interface, NULL);
2017                         if (ifp == NULL) {
2018                                 error = EADDRNOTAVAIL;
2019                                 splx(s);
2020                                 break;
2021                         }
2022                 }
2023                 /*
2024                  * Find the membership in the membership array.
2025                  */
2026                 for (i = 0; i < imo->imo_num_memberships; ++i) {
2027                         if ((ifp == NULL ||
2028                              imo->imo_membership[i]->inm_ifp == ifp) &&
2029                              imo->imo_membership[i]->inm_addr.s_addr ==
2030                              mreq.imr_multiaddr.s_addr)
2031                                 break;
2032                 }
2033                 if (i == imo->imo_num_memberships) {
2034                         error = EADDRNOTAVAIL;
2035                         splx(s);
2036                         break;
2037                 }
2038                 /*
2039                  * Give up the multicast address record to which the
2040                  * membership points.
2041                  */
2042                 in_delmulti(imo->imo_membership[i]);
2043                 /*
2044                  * Remove the gap in the membership array.
2045                  */
2046                 for (++i; i < imo->imo_num_memberships; ++i)
2047                         imo->imo_membership[i-1] = imo->imo_membership[i];
2048                 --imo->imo_num_memberships;
2049                 splx(s);
2050                 break;
2051
2052         default:
2053                 error = EOPNOTSUPP;
2054                 break;
2055         }
2056
2057         /*
2058          * If all options have default values, no need to keep the mbuf.
2059          */
2060         if (imo->imo_multicast_ifp == NULL &&
2061             imo->imo_multicast_vif == -1 &&
2062             imo->imo_multicast_ttl == IP_DEFAULT_MULTICAST_TTL &&
2063             imo->imo_multicast_loop == IP_DEFAULT_MULTICAST_LOOP &&
2064             imo->imo_num_memberships == 0) {
2065                 free(*imop, M_IPMOPTS);
2066                 *imop = NULL;
2067         }
2068
2069         return (error);
2070 }
2071
2072 /*
2073  * Return the IP multicast options in response to user getsockopt().
2074  */
2075 static int
2076 ip_getmoptions(sopt, imo)
2077         struct sockopt *sopt;
2078         struct ip_moptions *imo;
2079 {
2080         struct in_addr addr;
2081         struct in_ifaddr *ia;
2082         int error, optval;
2083         u_char coptval;
2084
2085         error = 0;
2086         switch (sopt->sopt_name) {
2087         case IP_MULTICAST_VIF:
2088                 if (imo != NULL)
2089                         optval = imo->imo_multicast_vif;
2090                 else
2091                         optval = -1;
2092                 error = sooptcopyout(sopt, &optval, sizeof optval);
2093                 break;
2094
2095         case IP_MULTICAST_IF:
2096                 if (imo == NULL || imo->imo_multicast_ifp == NULL)
2097                         addr.s_addr = INADDR_ANY;
2098                 else if (imo->imo_multicast_addr.s_addr) {
2099                         /* return the value user has set */
2100                         addr = imo->imo_multicast_addr;
2101                 } else {
2102                         IFP_TO_IA(imo->imo_multicast_ifp, ia);
2103                         addr.s_addr = (ia == NULL) ? INADDR_ANY
2104                                 : IA_SIN(ia)->sin_addr.s_addr;
2105                 }
2106                 error = sooptcopyout(sopt, &addr, sizeof addr);
2107                 break;
2108
2109         case IP_MULTICAST_TTL:
2110                 if (imo == 0)
2111                         optval = coptval = IP_DEFAULT_MULTICAST_TTL;
2112                 else
2113                         optval = coptval = imo->imo_multicast_ttl;
2114                 if (sopt->sopt_valsize == 1)
2115                         error = sooptcopyout(sopt, &coptval, 1);
2116                 else
2117                         error = sooptcopyout(sopt, &optval, sizeof optval);
2118                 break;
2119
2120         case IP_MULTICAST_LOOP:
2121                 if (imo == 0)
2122                         optval = coptval = IP_DEFAULT_MULTICAST_LOOP;
2123                 else
2124                         optval = coptval = imo->imo_multicast_loop;
2125                 if (sopt->sopt_valsize == 1)
2126                         error = sooptcopyout(sopt, &coptval, 1);
2127                 else
2128                         error = sooptcopyout(sopt, &optval, sizeof optval);
2129                 break;
2130
2131         default:
2132                 error = ENOPROTOOPT;
2133                 break;
2134         }
2135         return (error);
2136 }
2137
2138 /*
2139  * Discard the IP multicast options.
2140  */
2141 void
2142 ip_freemoptions(imo)
2143         struct ip_moptions *imo;
2144 {
2145         int i;
2146
2147         if (imo != NULL) {
2148                 for (i = 0; i < imo->imo_num_memberships; ++i)
2149                         in_delmulti(imo->imo_membership[i]);
2150                 free(imo, M_IPMOPTS);
2151         }
2152 }
2153
2154 /*
2155  * Routine called from ip_output() to loop back a copy of an IP multicast
2156  * packet to the input queue of a specified interface.  Note that this
2157  * calls the output routine of the loopback "driver", but with an interface
2158  * pointer that might NOT be a loopback interface -- evil, but easier than
2159  * replicating that code here.
2160  */
2161 static void
2162 ip_mloopback(ifp, m, dst, hlen)
2163         struct ifnet *ifp;
2164         struct mbuf *m;
2165         struct sockaddr_in *dst;
2166         int hlen;
2167 {
2168         struct ip *ip;
2169         struct mbuf *copym;
2170
2171         copym = m_copy(m, 0, M_COPYALL);
2172         if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen))
2173                 copym = m_pullup(copym, hlen);
2174         if (copym != NULL) {
2175                 /*
2176                  * if the checksum hasn't been computed, mark it as valid
2177                  */
2178                 if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
2179                         in_delayed_cksum(copym);
2180                         copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
2181                         copym->m_pkthdr.csum_flags |=
2182                             CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
2183                         copym->m_pkthdr.csum_data = 0xffff;
2184                 }
2185                 /*
2186                  * We don't bother to fragment if the IP length is greater
2187                  * than the interface's MTU.  Can this possibly matter?
2188                  */
2189                 ip = mtod(copym, struct ip *);
2190                 ip->ip_len = htons(ip->ip_len);
2191                 ip->ip_off = htons(ip->ip_off);
2192                 ip->ip_sum = 0;
2193                 if (ip->ip_vhl == IP_VHL_BORING) {
2194                         ip->ip_sum = in_cksum_hdr(ip);
2195                 } else {
2196                         ip->ip_sum = in_cksum(copym, hlen);
2197                 }
2198                 /*
2199                  * NB:
2200                  * It's not clear whether there are any lingering
2201                  * reentrancy problems in other areas which might
2202                  * be exposed by using ip_input directly (in
2203                  * particular, everything which modifies the packet
2204                  * in-place).  Yet another option is using the
2205                  * protosw directly to deliver the looped back
2206                  * packet.  For the moment, we'll err on the side
2207                  * of safety by using if_simloop().
2208                  */
2209 #if 1 /* XXX */
2210                 if (dst->sin_family != AF_INET) {
2211                         printf("ip_mloopback: bad address family %d\n",
2212                                                 dst->sin_family);
2213                         dst->sin_family = AF_INET;
2214                 }
2215 #endif
2216
2217 #ifdef notdef
2218                 copym->m_pkthdr.rcvif = ifp;
2219                 ip_input(copym);
2220 #else
2221                 if_simloop(ifp, copym, dst->sin_family, 0);
2222 #endif
2223         }
2224 }