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 1.20 2004/08/26 21:21:46 dillon 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 <netipsec/ipsec.h>
  82 #include <netipsec/xform.h>
  83 #include <netipsec/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 #ifdef IPSEC
 138         struct route iproute;
 139         struct secpolicy *sp = NULL;
 140         struct socket *so = inp ? inp->inp_socket : NULL;
 141 #endif
 142 #ifdef FAST_IPSEC
 143         struct route iproute;
 144         struct m_tag *mtag;
 145         struct secpolicy *sp = NULL;
 146         struct tdb_ident *tdbi;
 147         int s;
 148 #endif /* FAST_IPSEC */
 149         struct ip_fw_args args;
 150         int src_was_INADDR_ANY = 0;     /* as the name says... */
 151
 152         args.eh = NULL;
 153         args.rule = NULL;
 154         args.next_hop = NULL;
 155         args.divert_rule = 0;                   /* divert cookie */
 156
 157         /* Grab info from MT_TAG mbufs prepended to the chain. */
 158         for (; m0 && m0->m_type == MT_TAG; m0 = m0->m_next) {
 159                 switch(m0->_m_tag_id) {
 160                 default:
 161                         printf("ip_output: unrecognised MT_TAG tag %d\n",
 162                             m0->_m_tag_id);
 163                         break;
 164
 165                 case PACKET_TAG_DUMMYNET:
 166                         /*
 167                          * the packet was already tagged, so part of the
 168                          * processing was already done, and we need to go down.
 169                          * Get parameters from the header.
 170                          */
 171                         args.rule = ((struct dn_pkt *)m0)->rule;
 172                         opt = NULL ;
 173                         ro = & ( ((struct dn_pkt *)m0)->ro ) ;
 174                         imo = NULL ;
 175                         dst = ((struct dn_pkt *)m0)->dn_dst ;
 176                         ifp = ((struct dn_pkt *)m0)->ifp ;
 177                         flags = ((struct dn_pkt *)m0)->flags ;
 178                         break;
 179
 180                 case PACKET_TAG_DIVERT:
 181                         args.divert_rule = (int)m0->m_data & 0xffff;
 182                         break;
 183
 184                 case PACKET_TAG_IPFORWARD:
 185                         args.next_hop = (struct sockaddr_in *)m0->m_data;
 186                         break;
 187                 }
 188         }
 189         m = m0;
 190
 191         KASSERT(!m || (m->m_flags & M_PKTHDR) != 0, ("ip_output: no HDR"));
 192 #ifndef FAST_IPSEC
 193         KASSERT(ro != NULL, ("ip_output: no route, proto %d",
 194             mtod(m, struct ip *)->ip_p));
 195 #endif
 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 #ifdef FAST_IPSEC
 231         if (ro == NULL) {
 232                 ro = &iproute;
 233                 bzero(ro, sizeof (*ro));
 234         }
 235 #endif /* FAST_IPSEC */
 236         dst = (struct sockaddr_in *)&ro->ro_dst;
 237         /*
 238          * If there is a cached route,
 239          * check that it is to the same destination
 240          * and is still up.  If not, free it and try again.
 241          * The address family should also be checked in case of sharing the
 242          * cache with IPv6.
 243          */
 244         if (ro->ro_rt && ((ro->ro_rt->rt_flags & RTF_UP) == 0 ||
 245                           dst->sin_family != AF_INET ||
 246                           dst->sin_addr.s_addr != pkt_dst.s_addr)) {
 247                 RTFREE(ro->ro_rt);
 248                 ro->ro_rt = (struct rtentry *)0;
 249         }
 250         if (ro->ro_rt == 0) {
 251                 bzero(dst, sizeof(*dst));
 252                 dst->sin_family = AF_INET;
 253                 dst->sin_len = sizeof(*dst);
 254                 dst->sin_addr = pkt_dst;
 255         }
 256         /*
 257          * If routing to interface only,
 258          * short circuit routing lookup.
 259          */
 260         if (flags & IP_ROUTETOIF) {
 261                 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == 0 &&
 262                     (ia = ifatoia(ifa_ifwithnet(sintosa(dst)))) == 0) {
 263                         ipstat.ips_noroute++;
 264                         error = ENETUNREACH;
 265                         goto bad;
 266                 }
 267                 ifp = ia->ia_ifp;
 268                 ip->ip_ttl = 1;
 269                 isbroadcast = in_broadcast(dst->sin_addr, ifp);
 270         } else if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) &&
 271             imo != NULL && imo->imo_multicast_ifp != NULL) {
 272                 /*
 273                  * Bypass the normal routing lookup for multicast
 274                  * packets if the interface is specified.
 275                  */
 276                 ifp = imo->imo_multicast_ifp;
 277                 IFP_TO_IA(ifp, ia);
 278                 isbroadcast = 0;        /* fool gcc */
 279         } else {
 280                 /*
 281                  * If this is the case, we probably don't want to allocate
 282                  * a protocol-cloned route since we didn't get one from the
 283                  * ULP.  This lets TCP do its thing, while not burdening
 284                  * forwarding or ICMP with the overhead of cloning a route.
 285                  * Of course, we still want to do any cloning requested by
 286                  * the link layer, as this is probably required in all cases
 287                  * for correct operation (as it is for ARP).
 288                  */
 289                 if (ro->ro_rt == 0)
 290                         rtalloc_ign(ro, RTF_PRCLONING);
 291                 if (ro->ro_rt == 0) {
 292                         ipstat.ips_noroute++;
 293                         error = EHOSTUNREACH;
 294                         goto bad;
 295                 }
 296                 ia = ifatoia(ro->ro_rt->rt_ifa);
 297                 ifp = ro->ro_rt->rt_ifp;
 298                 ro->ro_rt->rt_use++;
 299                 if (ro->ro_rt->rt_flags & RTF_GATEWAY)
 300                         dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway;
 301                 if (ro->ro_rt->rt_flags & RTF_HOST)
 302                         isbroadcast = (ro->ro_rt->rt_flags & RTF_BROADCAST);
 303                 else
 304                         isbroadcast = in_broadcast(dst->sin_addr, ifp);
 305         }
 306         if (IN_MULTICAST(ntohl(pkt_dst.s_addr))) {
 307                 struct in_multi *inm;
 308
 309                 m->m_flags |= M_MCAST;
 310                 /*
 311                  * IP destination address is multicast.  Make sure "dst"
 312                  * still points to the address in "ro".  (It may have been
 313                  * changed to point to a gateway address, above.)
 314                  */
 315                 dst = (struct sockaddr_in *)&ro->ro_dst;
 316                 /*
 317                  * See if the caller provided any multicast options
 318                  */
 319                 if (imo != NULL) {
 320                         ip->ip_ttl = imo->imo_multicast_ttl;
 321                         if (imo->imo_multicast_vif != -1)
 322                                 ip->ip_src.s_addr =
 323                                     ip_mcast_src ?
 324                                     ip_mcast_src(imo->imo_multicast_vif) :
 325                                     INADDR_ANY;
 326                 } else
 327                         ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL;
 328                 /*
 329                  * Confirm that the outgoing interface supports multicast.
 330                  */
 331                 if ((imo == NULL) || (imo->imo_multicast_vif == -1)) {
 332                         if ((ifp->if_flags & IFF_MULTICAST) == 0) {
 333                                 ipstat.ips_noroute++;
 334                                 error = ENETUNREACH;
 335                                 goto bad;
 336                         }
 337                 }
 338                 /*
 339                  * If source address not specified yet, use address
 340                  * of outgoing interface.
 341                  */
 342                 if (ip->ip_src.s_addr == INADDR_ANY) {
 343                         /* Interface may have no addresses. */
 344                         if (ia != NULL)
 345                                 ip->ip_src = IA_SIN(ia)->sin_addr;
 346                 }
 347
 348                 IN_LOOKUP_MULTI(pkt_dst, ifp, inm);
 349                 if (inm != NULL &&
 350                    (imo == NULL || imo->imo_multicast_loop)) {
 351                         /*
 352                          * If we belong to the destination multicast group
 353                          * on the outgoing interface, and the caller did not
 354                          * forbid loopback, loop back a copy.
 355                          */
 356                         ip_mloopback(ifp, m, dst, hlen);
 357                 }
 358                 else {
 359                         /*
 360                          * If we are acting as a multicast router, perform
 361                          * multicast forwarding as if the packet had just
 362                          * arrived on the interface to which we are about
 363                          * to send.  The multicast forwarding function
 364                          * recursively calls this function, using the
 365                          * IP_FORWARDING flag to prevent infinite recursion.
 366                          *
 367                          * Multicasts that are looped back by ip_mloopback(),
 368                          * above, will be forwarded by the ip_input() routine,
 369                          * if necessary.
 370                          */
 371                         if (ip_mrouter && (flags & IP_FORWARDING) == 0) {
 372                                 /*
 373                                  * If rsvp daemon is not running, do not
 374                                  * set ip_moptions. This ensures that the packet
 375                                  * is multicast and not just sent down one link
 376                                  * as prescribed by rsvpd.
 377                                  */
 378                                 if (!rsvp_on)
 379                                         imo = NULL;
 380                                 if (ip_mforward &&
 381                                     ip_mforward(ip, ifp, m, imo) != 0) {
 382                                         m_freem(m);
 383                                         goto done;
 384                                 }
 385                         }
 386                 }
 387
 388                 /*
 389                  * Multicasts with a time-to-live of zero may be looped-
 390                  * back, above, but must not be transmitted on a network.
 391                  * Also, multicasts addressed to the loopback interface
 392                  * are not sent -- the above call to ip_mloopback() will
 393                  * loop back a copy if this host actually belongs to the
 394                  * destination group on the loopback interface.
 395                  */
 396                 if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) {
 397                         m_freem(m);
 398                         goto done;
 399                 }
 400
 401                 goto sendit;
 402         }
 403 #ifndef notdef
 404         /*
 405          * If the source address is not specified yet, use the address
 406          * of the outoing interface. In case, keep note we did that, so
 407          * if the the firewall changes the next-hop causing the output
 408          * interface to change, we can fix that.
 409          */
 410         if (ip->ip_src.s_addr == INADDR_ANY) {
 411                 /* Interface may have no addresses. */
 412                 if (ia != NULL) {
 413                         ip->ip_src = IA_SIN(ia)->sin_addr;
 414                         src_was_INADDR_ANY = 1;
 415                 }
 416         }
 417 #endif /* notdef */
 418         /*
 419          * Verify that we have any chance at all of being able to queue
 420          *      the packet or packet fragments
 421          */
 422         if ((ifp->if_snd.ifq_len + ip->ip_len / ifp->if_mtu + 1) >=
 423                 ifp->if_snd.ifq_maxlen) {
 424                         error = ENOBUFS;
 425                         ipstat.ips_odropped++;
 426                         goto bad;
 427         }
 428
 429         /*
 430          * Look for broadcast address and
 431          * verify user is allowed to send
 432          * such a packet.
 433          */
 434         if (isbroadcast) {
 435                 if ((ifp->if_flags & IFF_BROADCAST) == 0) {
 436                         error = EADDRNOTAVAIL;
 437                         goto bad;
 438                 }
 439                 if ((flags & IP_ALLOWBROADCAST) == 0) {
 440                         error = EACCES;
 441                         goto bad;
 442                 }
 443                 /* don't allow broadcast messages to be fragmented */
 444                 if (ip->ip_len > ifp->if_mtu) {
 445                         error = EMSGSIZE;
 446                         goto bad;
 447                 }
 448                 m->m_flags |= M_BCAST;
 449         } else {
 450                 m->m_flags &= ~M_BCAST;
 451         }
 452
 453 sendit:
 454 #ifdef IPSEC
 455         /* get SP for this packet */
 456         if (so == NULL)
 457                 sp = ipsec4_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, flags, &error);
 458         else
 459                 sp = ipsec4_getpolicybysock(m, IPSEC_DIR_OUTBOUND, so, &error);
 460
 461         if (sp == NULL) {
 462                 ipsecstat.out_inval++;
 463                 goto bad;
 464         }
 465
 466         error = 0;
 467
 468         /* check policy */
 469         switch (sp->policy) {
 470         case IPSEC_POLICY_DISCARD:
 471                 /*
 472                  * This packet is just discarded.
 473                  */
 474                 ipsecstat.out_polvio++;
 475                 goto bad;
 476
 477         case IPSEC_POLICY_BYPASS:
 478         case IPSEC_POLICY_NONE:
 479                 /* no need to do IPsec. */
 480                 goto skip_ipsec;
 481
 482         case IPSEC_POLICY_IPSEC:
 483                 if (sp->req == NULL) {
 484                         /* acquire a policy */
 485                         error = key_spdacquire(sp);
 486                         goto bad;
 487                 }
 488                 break;
 489
 490         case IPSEC_POLICY_ENTRUST:
 491         default:
 492                 printf("ip_output: Invalid policy found. %d\n", sp->policy);
 493         }
 494     {
 495         struct ipsec_output_state state;
 496         bzero(&state, sizeof(state));
 497         state.m = m;
 498         if (flags & IP_ROUTETOIF) {
 499                 state.ro = &iproute;
 500                 bzero(&iproute, sizeof(iproute));
 501         } else
 502                 state.ro = ro;
 503         state.dst = (struct sockaddr *)dst;
 504
 505         ip->ip_sum = 0;
 506
 507         /*
 508          * XXX
 509          * delayed checksums are not currently compatible with IPsec
 510          */
 511         if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 512                 in_delayed_cksum(m);
 513                 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
 514         }
 515
 516         ip->ip_len = htons(ip->ip_len);
 517         ip->ip_off = htons(ip->ip_off);
 518
 519         error = ipsec4_output(&state, sp, flags);
 520
 521         m = state.m;
 522         if (flags & IP_ROUTETOIF) {
 523                 /*
 524                  * if we have tunnel mode SA, we may need to ignore
 525                  * IP_ROUTETOIF.
 526                  */
 527                 if (state.ro != &iproute || state.ro->ro_rt != NULL) {
 528                         flags &= ~IP_ROUTETOIF;
 529                         ro = state.ro;
 530                 }
 531         } else
 532                 ro = state.ro;
 533         dst = (struct sockaddr_in *)state.dst;
 534         if (error) {
 535                 /* mbuf is already reclaimed in ipsec4_output. */
 536                 m0 = NULL;
 537                 switch (error) {
 538                 case EHOSTUNREACH:
 539                 case ENETUNREACH:
 540                 case EMSGSIZE:
 541                 case ENOBUFS:
 542                 case ENOMEM:
 543                         break;
 544                 default:
 545                         printf("ip4_output (ipsec): error code %d\n", error);
 546                         /*fall through*/
 547                 case ENOENT:
 548                         /* don't show these error codes to the user */
 549                         error = 0;
 550                         break;
 551                 }
 552                 goto bad;
 553         }
 554     }
 555
 556         /* be sure to update variables that are affected by ipsec4_output() */
 557         ip = mtod(m, struct ip *);
 558 #ifdef _IP_VHL
 559         hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 560 #else
 561         hlen = ip->ip_hl << 2;
 562 #endif
 563         if (ro->ro_rt == NULL) {
 564                 if ((flags & IP_ROUTETOIF) == 0) {
 565                         printf("ip_output: "
 566                                 "can't update route after IPsec processing\n");
 567                         error = EHOSTUNREACH;   /*XXX*/
 568                         goto bad;
 569                 }
 570         } else {
 571                 ia = ifatoia(ro->ro_rt->rt_ifa);
 572                 ifp = ro->ro_rt->rt_ifp;
 573         }
 574
 575         /* make it flipped, again. */
 576         ip->ip_len = ntohs(ip->ip_len);
 577         ip->ip_off = ntohs(ip->ip_off);
 578 skip_ipsec:
 579 #endif /*IPSEC*/
 580 #ifdef FAST_IPSEC
 581         /*
 582          * Check the security policy (SP) for the packet and, if
 583          * required, do IPsec-related processing.  There are two
 584          * cases here; the first time a packet is sent through
 585          * it will be untagged and handled by ipsec4_checkpolicy.
 586          * If the packet is resubmitted to ip_output (e.g. after
 587          * AH, ESP, etc. processing), there will be a tag to bypass
 588          * the lookup and related policy checking.
 589          */
 590         mtag = m_tag_find(m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
 591         s = splnet();
 592         if (mtag != NULL) {
 593                 tdbi = (struct tdb_ident *)(mtag + 1);
 594                 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
 595                 if (sp == NULL)
 596                         error = -EINVAL;        /* force silent drop */
 597                 m_tag_delete(m, mtag);
 598         } else {
 599                 sp = ipsec4_checkpolicy(m, IPSEC_DIR_OUTBOUND, flags,
 600                                         &error, inp);
 601         }
 602         /*
 603          * There are four return cases:
 604          *    sp != NULL                    apply IPsec policy
 605          *    sp == NULL, error == 0        no IPsec handling needed
 606          *    sp == NULL, error == -EINVAL  discard packet w/o error
 607          *    sp == NULL, error != 0        discard packet, report error
 608          */
 609         if (sp != NULL) {
 610                 /* Loop detection, check if ipsec processing already done */
 611                 KASSERT(sp->req != NULL, ("ip_output: no ipsec request"));
 612                 for (mtag = m_tag_first(m); mtag != NULL;
 613                      mtag = m_tag_next(m, mtag)) {
 614                         if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
 615                                 continue;
 616                         if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
 617                             mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
 618                                 continue;
 619                         /*
 620                          * Check if policy has an SA associated with it.
 621                          * This can happen when an SP has yet to acquire
 622                          * an SA; e.g. on first reference.  If it occurs,
 623                          * then we let ipsec4_process_packet do its thing.
 624                          */
 625                         if (sp->req->sav == NULL)
 626                                 break;
 627                         tdbi = (struct tdb_ident *)(mtag + 1);
 628                         if (tdbi->spi == sp->req->sav->spi &&
 629                             tdbi->proto == sp->req->sav->sah->saidx.proto &&
 630                             bcmp(&tdbi->dst, &sp->req->sav->sah->saidx.dst,
 631                                  sizeof (union sockaddr_union)) == 0) {
 632                                 /*
 633                                  * No IPsec processing is needed, free
 634                                  * reference to SP.
 635                                  *
 636                                  * NB: null pointer to avoid free at
 637                                  *     done: below.
 638                                  */
 639                                 KEY_FREESP(&sp), sp = NULL;
 640                                 splx(s);
 641                                 goto spd_done;
 642                         }
 643                 }
 644
 645                 /*
 646                  * Do delayed checksums now because we send before
 647                  * this is done in the normal processing path.
 648                  */
 649                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 650                         in_delayed_cksum(m);
 651                         m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
 652                 }
 653
 654                 ip->ip_len = htons(ip->ip_len);
 655                 ip->ip_off = htons(ip->ip_off);
 656
 657                 /* NB: callee frees mbuf */
 658                 error = ipsec4_process_packet(m, sp->req, flags, 0);
 659                 /*
 660                  * Preserve KAME behaviour: ENOENT can be returned
 661                  * when an SA acquire is in progress.  Don't propagate
 662                  * this to user-level; it confuses applications.
 663                  *
 664                  * XXX this will go away when the SADB is redone.
 665                  */
 666                 if (error == ENOENT)
 667                         error = 0;
 668                 splx(s);
 669                 goto done;
 670         } else {
 671                 splx(s);
 672
 673                 if (error != 0) {
 674                         /*
 675                          * Hack: -EINVAL is used to signal that a packet
 676                          * should be silently discarded.  This is typically
 677                          * because we asked key management for an SA and
 678                          * it was delayed (e.g. kicked up to IKE).
 679                          */
 680                         if (error == -EINVAL)
 681                                 error = 0;
 682                         goto bad;
 683                 } else {
 684                         /* No IPsec processing for this packet. */
 685                 }
 686 #ifdef notyet
 687                 /*
 688                  * If deferred crypto processing is needed, check that
 689                  * the interface supports it.
 690                  */
 691                 mtag = m_tag_find(m, PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED, NULL);
 692                 if (mtag != NULL && (ifp->if_capenable & IFCAP_IPSEC) == 0) {
 693                         /* notify IPsec to do its own crypto */
 694                         ipsp_skipcrypto_unmark((struct tdb_ident *)(mtag + 1));
 695                         error = EHOSTUNREACH;
 696                         goto bad;
 697                 }
 698 #endif
 699         }
 700 spd_done:
 701 #endif /* FAST_IPSEC */
 702         /*
 703          * IpHack's section.
 704          * - Xlate: translate packet's addr/port (NAT).
 705          * - Firewall: deny/allow/etc.
 706          * - Wrap: fake packet's addr/port <unimpl.>
 707          * - Encapsulate: put it in another IP and send out. <unimp.>
 708          */
 709
 710         /*
 711          * Run through list of hooks for output packets.
 712          */
 713         if (pfil_has_hooks(&inet_pfil_hook)) {
 714                 error = pfil_run_hooks(&inet_pfil_hook, &m, ifp, PFIL_OUT);
 715                 if (error != 0 || m == NULL)
 716                         goto done;
 717                 ip = mtod(m, struct ip *);
 718         }
 719
 720         /*
 721          * Check with the firewall...
 722          * but not if we are already being fwd'd from a firewall.
 723          */
 724         if (fw_enable && IPFW_LOADED && !args.next_hop) {
 725                 struct sockaddr_in *old = dst;
 726
 727                 args.m = m;
 728                 args.next_hop = dst;
 729                 args.oif = ifp;
 730                 off = ip_fw_chk_ptr(&args);
 731                 m = args.m;
 732                 dst = args.next_hop;
 733
 734                 /*
 735                  * On return we must do the following:
 736                  * m == NULL    -> drop the pkt (old interface, deprecated)
 737                  * (off & IP_FW_PORT_DENY_FLAG) -> drop the pkt (new interface)
 738                  * 1<=off<= 0xffff              -> DIVERT
 739                  * (off & IP_FW_PORT_DYNT_FLAG) -> send to a DUMMYNET pipe
 740                  * (off & IP_FW_PORT_TEE_FLAG)  -> TEE the packet
 741                  * dst != old                   -> IPFIREWALL_FORWARD
 742                  * off==0, dst==old             -> accept
 743                  * If some of the above modules are not compiled in, then
 744                  * we should't have to check the corresponding condition
 745                  * (because the ipfw control socket should not accept
 746                  * unsupported rules), but better play safe and drop
 747                  * packets in case of doubt.
 748                  */
 749                 if ( (off & IP_FW_PORT_DENY_FLAG) || m == NULL) {
 750                         if (m)
 751                                 m_freem(m);
 752                         error = EACCES;
 753                         goto done;
 754                 }
 755                 ip = mtod(m, struct ip *);
 756                 if (off == 0 && dst == old)             /* common case */
 757                         goto pass;
 758                 if (DUMMYNET_LOADED && (off & IP_FW_PORT_DYNT_FLAG) != 0) {
 759                         /*
 760                          * pass the pkt to dummynet. Need to include
 761                          * pipe number, m, ifp, ro, dst because these are
 762                          * not recomputed in the next pass.
 763                          * All other parameters have been already used and
 764                          * so they are not needed anymore.
 765                          * XXX note: if the ifp or ro entry are deleted
 766                          * while a pkt is in dummynet, we are in trouble!
 767                          */
 768                         args.ro = ro;
 769                         args.dst = dst;
 770                         args.flags = flags;
 771
 772                         error = ip_dn_io_ptr(m, off & 0xffff, DN_TO_IP_OUT,
 773                                 &args);
 774                         goto done;
 775                 }
 776 #ifdef IPDIVERT
 777                 if (off != 0 && (off & IP_FW_PORT_DYNT_FLAG) == 0) {
 778                         struct mbuf *clone = NULL;
 779
 780                         /* Clone packet if we're doing a 'tee' */
 781                         if ((off & IP_FW_PORT_TEE_FLAG) != 0)
 782                                 clone = m_dup(m, MB_DONTWAIT);
 783
 784                         /*
 785                          * XXX
 786                          * delayed checksums are not currently compatible
 787                          * with divert sockets.
 788                          */
 789                         if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 790                                 in_delayed_cksum(m);
 791                                 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
 792                         }
 793
 794                         /* Restore packet header fields to original values */
 795                         ip->ip_len = htons(ip->ip_len);
 796                         ip->ip_off = htons(ip->ip_off);
 797
 798                         /* Deliver packet to divert input routine */
 799                         divert_packet(m, 0, off & 0xffff, args.divert_rule);
 800
 801                         /* If 'tee', continue with original packet */
 802                         if (clone != NULL) {
 803                                 m = clone;
 804                                 ip = mtod(m, struct ip *);
 805                                 goto pass;
 806                         }
 807                         goto done;
 808                 }
 809 #endif
 810
 811                 /* IPFIREWALL_FORWARD */
 812                 /*
 813                  * Check dst to make sure it is directly reachable on the
 814                  * interface we previously thought it was.
 815                  * If it isn't (which may be likely in some situations) we have
 816                  * to re-route it (ie, find a route for the next-hop and the
 817                  * associated interface) and set them here. This is nested
 818                  * forwarding which in most cases is undesirable, except where
 819                  * such control is nigh impossible. So we do it here.
 820                  * And I'm babbling.
 821                  */
 822                 if (off == 0 && old != dst) { /* FORWARD, dst has changed */
 823 #if 0
 824                         /*
 825                          * XXX To improve readability, this block should be
 826                          * changed into a function call as below:
 827                          */
 828                         error = ip_ipforward(&m, &dst, &ifp);
 829                         if (error)
 830                                 goto bad;
 831                         if (m == NULL) /* ip_input consumed the mbuf */
 832                                 goto done;
 833 #else
 834                         struct in_ifaddr *ia;
 835
 836                         /*
 837                          * XXX sro_fwd below is static, and a pointer
 838                          * to it gets passed to routines downstream.
 839                          * This could have surprisingly bad results in
 840                          * practice, because its content is overwritten
 841                          * by subsequent packets.
 842                          */
 843                         /* There must be a better way to do this next line... */
 844                         static struct route sro_fwd;
 845                         struct route *ro_fwd = &sro_fwd;
 846
 847 #if 0
 848                         print_ip("IPFIREWALL_FORWARD: New dst ip: ",
 849                             dst->sin_addr, "\n");
 850 #endif
 851
 852                         /*
 853                          * We need to figure out if we have been forwarded
 854                          * to a local socket. If so, then we should somehow
 855                          * "loop back" to ip_input, and get directed to the
 856                          * PCB as if we had received this packet. This is
 857                          * because it may be dificult to identify the packets
 858                          * you want to forward until they are being output
 859                          * and have selected an interface. (e.g. locally
 860                          * initiated packets) If we used the loopback inteface,
 861                          * we would not be able to control what happens
 862                          * as the packet runs through ip_input() as
 863                          * it is done through a ISR.
 864                          */
 865                         LIST_FOREACH(ia,
 866                             INADDR_HASH(dst->sin_addr.s_addr), ia_hash) {
 867                                 /*
 868                                  * If the addr to forward to is one
 869                                  * of ours, we pretend to
 870                                  * be the destination for this packet.
 871                                  */
 872                                 if (IA_SIN(ia)->sin_addr.s_addr ==
 873                                                  dst->sin_addr.s_addr)
 874                                         break;
 875                         }
 876                         if (ia) {       /* tell ip_input "dont filter" */
 877                                 struct m_hdr tag;
 878
 879                                 tag.mh_type = MT_TAG;
 880                                 tag.mh_flags = PACKET_TAG_IPFORWARD;
 881                                 tag.mh_data = (caddr_t)args.next_hop;
 882                                 tag.mh_next = m;
 883
 884                                 if (m->m_pkthdr.rcvif == NULL)
 885                                         m->m_pkthdr.rcvif = ifunit("lo0");
 886                                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 887                                         m->m_pkthdr.csum_flags |=
 888                                             CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
 889                                         m0->m_pkthdr.csum_data = 0xffff;
 890                                 }
 891                                 m->m_pkthdr.csum_flags |=
 892                                     CSUM_IP_CHECKED | CSUM_IP_VALID;
 893                                 ip->ip_len = htons(ip->ip_len);
 894                                 ip->ip_off = htons(ip->ip_off);
 895                                 ip_input((struct mbuf *)&tag);
 896                                 goto done;
 897                         }
 898                         /* Some of the logic for this was
 899                          * nicked from above.
 900                          *
 901                          * This rewrites the cached route in a local PCB.
 902                          * Is this what we want to do?
 903                          */
 904                         bcopy(dst, &ro_fwd->ro_dst, sizeof(*dst));
 905
 906                         ro_fwd->ro_rt = 0;
 907                         rtalloc_ign(ro_fwd, RTF_PRCLONING);
 908
 909                         if (ro_fwd->ro_rt == 0) {
 910                                 ipstat.ips_noroute++;
 911                                 error = EHOSTUNREACH;
 912                                 goto bad;
 913                         }
 914
 915                         ia = ifatoia(ro_fwd->ro_rt->rt_ifa);
 916                         ifp = ro_fwd->ro_rt->rt_ifp;
 917                         ro_fwd->ro_rt->rt_use++;
 918                         if (ro_fwd->ro_rt->rt_flags & RTF_GATEWAY)
 919                                 dst = (struct sockaddr_in *)
 920                                         ro_fwd->ro_rt->rt_gateway;
 921                         if (ro_fwd->ro_rt->rt_flags & RTF_HOST)
 922                                 isbroadcast =
 923                                     (ro_fwd->ro_rt->rt_flags & RTF_BROADCAST);
 924                         else
 925                                 isbroadcast = in_broadcast(dst->sin_addr, ifp);
 926                         if (ro->ro_rt)
 927                                 RTFREE(ro->ro_rt);
 928                         ro->ro_rt = ro_fwd->ro_rt;
 929                         dst = (struct sockaddr_in *)&ro_fwd->ro_dst;
 930
 931 #endif  /* ... block to be put into a function */
 932                         /*
 933                          * If we added a default src ip earlier,
 934                          * which would have been gotten from the-then
 935                          * interface, do it again, from the new one.
 936                          */
 937                         if (src_was_INADDR_ANY)
 938                                 ip->ip_src = IA_SIN(ia)->sin_addr;
 939                         goto pass ;
 940                 }
 941
 942                 /*
 943                  * if we get here, none of the above matches, and
 944                  * we have to drop the pkt
 945                  */
 946                 m_freem(m);
 947                 error = EACCES; /* not sure this is the right error msg */
 948                 goto done;
 949         }
 950
 951 pass:
 952         /* 127/8 must not appear on wire - RFC1122. */
 953         if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
 954             (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
 955                 if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
 956                         ipstat.ips_badaddr++;
 957                         error = EADDRNOTAVAIL;
 958                         goto bad;
 959                 }
 960         }
 961
 962         m->m_pkthdr.csum_flags |= CSUM_IP;
 963         sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_hwassist;
 964         if (sw_csum & CSUM_DELAY_DATA) {
 965                 in_delayed_cksum(m);
 966                 sw_csum &= ~CSUM_DELAY_DATA;
 967         }
 968         m->m_pkthdr.csum_flags &= ifp->if_hwassist;
 969
 970         /*
 971          * If small enough for interface, or the interface will take
 972          * care of the fragmentation for us, can just send directly.
 973          */
 974         if (ip->ip_len <= ifp->if_mtu || ((ifp->if_hwassist & CSUM_FRAGMENT) &&
 975             (ip->ip_off & IP_DF) == 0)) {
 976                 ip->ip_len = htons(ip->ip_len);
 977                 ip->ip_off = htons(ip->ip_off);
 978                 ip->ip_sum = 0;
 979                 if (sw_csum & CSUM_DELAY_IP) {
 980                         if (ip->ip_vhl == IP_VHL_BORING) {
 981                                 ip->ip_sum = in_cksum_hdr(ip);
 982                         } else {
 983                                 ip->ip_sum = in_cksum(m, hlen);
 984                         }
 985                 }
 986
 987                 /* Record statistics for this interface address. */
 988                 if (!(flags & IP_FORWARDING) && ia) {
 989                         ia->ia_ifa.if_opackets++;
 990                         ia->ia_ifa.if_obytes += m->m_pkthdr.len;
 991                 }
 992
 993 #ifdef IPSEC
 994                 /* clean ipsec history once it goes out of the node */
 995                 ipsec_delaux(m);
 996 #endif
 997
 998 #ifdef MBUF_STRESS_TEST
 999                 if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size) {
1000                         struct mbuf *m1, *m2;
1001                         int length, tmp;
1002
1003                         tmp = length = m->m_pkthdr.len;
1004
1005                         while ((length -= mbuf_frag_size) >= 1) {
1006                                 m1 = m_split(m, length, MB_DONTWAIT);
1007                                 if (m1 == NULL)
1008                                         break;
1009                                 m1->m_flags &= ~M_PKTHDR;
1010                                 m2 = m;
1011                                 while (m2->m_next != NULL)
1012                                         m2 = m2->m_next;
1013                                 m2->m_next = m1;
1014                         }
1015                         m->m_pkthdr.len = tmp;
1016                 }
1017 #endif
1018                 error = (*ifp->if_output)(ifp, m,
1019                                 (struct sockaddr *)dst, ro->ro_rt);
1020                 goto done;
1021         }
1022
1023         if (ip->ip_off & IP_DF) {
1024                 error = EMSGSIZE;
1025                 /*
1026                  * This case can happen if the user changed the MTU
1027                  * of an interface after enabling IP on it.  Because
1028                  * most netifs don't keep track of routes pointing to
1029                  * them, there is no way for one to update all its
1030                  * routes when the MTU is changed.
1031                  */
1032                 if ((ro->ro_rt->rt_flags & (RTF_UP | RTF_HOST)) &&
1033                     !(ro->ro_rt->rt_rmx.rmx_locks & RTV_MTU) &&
1034                     (ro->ro_rt->rt_rmx.rmx_mtu > ifp->if_mtu)) {
1035                         ro->ro_rt->rt_rmx.rmx_mtu = ifp->if_mtu;
1036                 }
1037                 ipstat.ips_cantfrag++;
1038                 goto bad;
1039         }
1040
1041         /*
1042          * Too large for interface; fragment if possible. If successful,
1043          * on return, m will point to a list of packets to be sent.
1044          */
1045         error = ip_fragment(ip, &m, ifp->if_mtu, ifp->if_hwassist, sw_csum);
1046         if (error)
1047                 goto bad;
1048         for (; m; m = m0) {
1049                 m0 = m->m_nextpkt;
1050                 m->m_nextpkt = 0;
1051 #ifdef IPSEC
1052                 /* clean ipsec history once it goes out of the node */
1053                 ipsec_delaux(m);
1054 #endif
1055                 if (error == 0) {
1056                         /* Record statistics for this interface address. */
1057                         if (ia != NULL) {
1058                                 ia->ia_ifa.if_opackets++;
1059                                 ia->ia_ifa.if_obytes += m->m_pkthdr.len;
1060                         }
1061
1062                         error = (*ifp->if_output)(ifp, m,
1063                             (struct sockaddr *)dst, ro->ro_rt);
1064                 } else
1065                         m_freem(m);
1066         }
1067
1068         if (error == 0)
1069                 ipstat.ips_fragmented++;
1070
1071 done:
1072 #ifdef IPSEC
1073         if (ro == &iproute && ro->ro_rt) {
1074                 RTFREE(ro->ro_rt);
1075                 ro->ro_rt = NULL;
1076         }
1077         if (sp != NULL) {
1078                 KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
1079                         printf("DP ip_output call free SP:%p\n", sp));
1080                 key_freesp(sp);
1081         }
1082 #endif
1083 #ifdef FAST_IPSEC
1084         if (ro == &iproute && ro->ro_rt) {
1085                 RTFREE(ro->ro_rt);
1086                 ro->ro_rt = NULL;
1087         }
1088         if (sp != NULL)
1089                 KEY_FREESP(&sp);
1090 #endif
1091         return (error);
1092 bad:
1093         m_freem(m);
1094         goto done;
1095 }
1096
1097 /*
1098  * Create a chain of fragments which fit the given mtu. m_frag points to the
1099  * mbuf to be fragmented; on return it points to the chain with the fragments.
1100  * Return 0 if no error. If error, m_frag may contain a partially built
1101  * chain of fragments that should be freed by the caller.
1102  *
1103  * if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist)
1104  * sw_csum contains the delayed checksums flags (e.g., CSUM_DELAY_IP).
1105  */
1106 int
1107 ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu,
1108             u_long if_hwassist_flags, int sw_csum)
1109 {
1110         int error = 0;
1111         int hlen = IP_VHL_HL(ip->ip_vhl) << 2;
1112         int len = (mtu - hlen) & ~7;    /* size of payload in each fragment */
1113         int off;
1114         struct mbuf *m0 = *m_frag;      /* the original packet          */
1115         int firstlen;
1116         struct mbuf **mnext;
1117         int nfrags;
1118
1119         if (ip->ip_off & IP_DF) {       /* Fragmentation not allowed */
1120                 ipstat.ips_cantfrag++;
1121                 return EMSGSIZE;
1122         }
1123
1124         /*
1125          * Must be able to put at least 8 bytes per fragment.
1126          */
1127         if (len < 8)
1128                 return EMSGSIZE;
1129
1130         /*
1131          * If the interface will not calculate checksums on
1132          * fragmented packets, then do it here.
1133          */
1134         if (m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA &&
1135             (if_hwassist_flags & CSUM_IP_FRAGS) == 0) {
1136                 in_delayed_cksum(m0);
1137                 m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
1138         }
1139
1140         if (len > PAGE_SIZE) {
1141                 /*
1142                  * Fragment large datagrams such that each segment
1143                  * contains a multiple of PAGE_SIZE amount of data,
1144                  * plus headers. This enables a receiver to perform
1145                  * page-flipping zero-copy optimizations.
1146                  *
1147                  * XXX When does this help given that sender and receiver
1148                  * could have different page sizes, and also mtu could
1149                  * be less than the receiver's page size ?
1150                  */
1151                 int newlen;
1152                 struct mbuf *m;
1153
1154                 for (m = m0, off = 0; m && (off+m->m_len) <= mtu; m = m->m_next)
1155                         off += m->m_len;
1156
1157                 /*
1158                  * firstlen (off - hlen) must be aligned on an
1159                  * 8-byte boundary
1160                  */
1161                 if (off < hlen)
1162                         goto smart_frag_failure;
1163                 off = ((off - hlen) & ~7) + hlen;
1164                 newlen = (~PAGE_MASK) & mtu;
1165                 if ((newlen + sizeof (struct ip)) > mtu) {
1166                         /* we failed, go back the default */
1167 smart_frag_failure:
1168                         newlen = len;
1169                         off = hlen + len;
1170                 }
1171                 len = newlen;
1172
1173         } else {
1174                 off = hlen + len;
1175         }
1176
1177         firstlen = off - hlen;
1178         mnext = &m0->m_nextpkt;         /* pointer to next packet */
1179
1180         /*
1181          * Loop through length of segment after first fragment,
1182          * make new header and copy data of each part and link onto chain.
1183          * Here, m0 is the original packet, m is the fragment being created.
1184          * The fragments are linked off the m_nextpkt of the original
1185          * packet, which after processing serves as the first fragment.
1186          */
1187         for (nfrags = 1; off < ip->ip_len; off += len, nfrags++) {
1188                 struct ip *mhip;        /* ip header on the fragment */
1189                 struct mbuf *m;
1190                 int mhlen = sizeof (struct ip);
1191
1192                 MGETHDR(m, MB_DONTWAIT, MT_HEADER);
1193                 if (m == 0) {
1194                         error = ENOBUFS;
1195                         ipstat.ips_odropped++;
1196                         goto done;
1197                 }
1198                 m->m_flags |= (m0->m_flags & M_MCAST) | M_FRAG;
1199                 /*
1200                  * In the first mbuf, leave room for the link header, then
1201                  * copy the original IP header including options. The payload
1202                  * goes into an additional mbuf chain returned by m_copy().
1203                  */
1204                 m->m_data += max_linkhdr;
1205                 mhip = mtod(m, struct ip *);
1206                 *mhip = *ip;
1207                 if (hlen > sizeof (struct ip)) {
1208                         mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
1209                         mhip->ip_vhl = IP_MAKE_VHL(IPVERSION, mhlen >> 2);
1210                 }
1211                 m->m_len = mhlen;
1212                 /* XXX do we need to add ip->ip_off below ? */
1213                 mhip->ip_off = ((off - hlen) >> 3) + ip->ip_off;
1214                 if (off + len >= ip->ip_len) {  /* last fragment */
1215                         len = ip->ip_len - off;
1216                         m->m_flags |= M_LASTFRAG;
1217                 } else
1218                         mhip->ip_off |= IP_MF;
1219                 mhip->ip_len = htons((u_short)(len + mhlen));
1220                 m->m_next = m_copy(m0, off, len);
1221                 if (m->m_next == 0) {           /* copy failed */
1222                         m_free(m);
1223                         error = ENOBUFS;        /* ??? */
1224                         ipstat.ips_odropped++;
1225                         goto done;
1226                 }
1227                 m->m_pkthdr.len = mhlen + len;
1228                 m->m_pkthdr.rcvif = (struct ifnet *)0;
1229                 m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags;
1230                 mhip->ip_off = htons(mhip->ip_off);
1231                 mhip->ip_sum = 0;
1232                 if (sw_csum & CSUM_DELAY_IP)
1233                         mhip->ip_sum = in_cksum(m, mhlen);
1234                 *mnext = m;
1235                 mnext = &m->m_nextpkt;
1236         }
1237         ipstat.ips_ofragments += nfrags;
1238
1239         /* set first marker for fragment chain */
1240         m0->m_flags |= M_FIRSTFRAG | M_FRAG;
1241         m0->m_pkthdr.csum_data = nfrags;
1242
1243         /*
1244          * Update first fragment by trimming what's been copied out
1245          * and updating header.
1246          */
1247         m_adj(m0, hlen + firstlen - ip->ip_len);
1248         m0->m_pkthdr.len = hlen + firstlen;
1249         ip->ip_len = htons((u_short)m0->m_pkthdr.len);
1250         ip->ip_off |= IP_MF;
1251         ip->ip_off = htons(ip->ip_off);
1252         ip->ip_sum = 0;
1253         if (sw_csum & CSUM_DELAY_IP)
1254                 ip->ip_sum = in_cksum(m0, hlen);
1255
1256 done:
1257         *m_frag = m0;
1258         return error;
1259 }
1260
1261 void
1262 in_delayed_cksum(struct mbuf *m)
1263 {
1264         struct ip *ip;
1265         u_short csum, offset;
1266
1267         ip = mtod(m, struct ip *);
1268         offset = IP_VHL_HL(ip->ip_vhl) << 2 ;
1269         csum = in_cksum_skip(m, ip->ip_len, offset);
1270         if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0)
1271                 csum = 0xffff;
1272         offset += m->m_pkthdr.csum_data;        /* checksum offset */
1273
1274         if (offset + sizeof(u_short) > m->m_len) {
1275                 printf("delayed m_pullup, m->len: %d  off: %d  p: %d\n",
1276                     m->m_len, offset, ip->ip_p);
1277                 /*
1278                  * XXX
1279                  * this shouldn't happen, but if it does, the
1280                  * correct behavior may be to insert the checksum
1281                  * in the existing chain instead of rearranging it.
1282                  */
1283                 m = m_pullup(m, offset + sizeof(u_short));
1284         }
1285         *(u_short *)(m->m_data + offset) = csum;
1286 }
1287
1288 /*
1289  * Insert IP options into preformed packet.
1290  * Adjust IP destination as required for IP source routing,
1291  * as indicated by a non-zero in_addr at the start of the options.
1292  *
1293  * XXX This routine assumes that the packet has no options in place.
1294  */
1295 static struct mbuf *
1296 ip_insertoptions(m, opt, phlen)
1297         struct mbuf *m;
1298         struct mbuf *opt;
1299         int *phlen;
1300 {
1301         struct ipoption *p = mtod(opt, struct ipoption *);
1302         struct mbuf *n;
1303         struct ip *ip = mtod(m, struct ip *);
1304         unsigned optlen;
1305
1306         optlen = opt->m_len - sizeof(p->ipopt_dst);
1307         if (optlen + (u_short)ip->ip_len > IP_MAXPACKET) {
1308                 *phlen = 0;
1309                 return (m);             /* XXX should fail */
1310         }
1311         if (p->ipopt_dst.s_addr)
1312                 ip->ip_dst = p->ipopt_dst;
1313         if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) {
1314                 MGETHDR(n, MB_DONTWAIT, MT_HEADER);
1315                 if (n == 0) {
1316                         *phlen = 0;
1317                         return (m);
1318                 }
1319                 n->m_pkthdr.rcvif = (struct ifnet *)0;
1320                 n->m_pkthdr.len = m->m_pkthdr.len + optlen;
1321                 m->m_len -= sizeof(struct ip);
1322                 m->m_data += sizeof(struct ip);
1323                 n->m_next = m;
1324                 m = n;
1325                 m->m_len = optlen + sizeof(struct ip);
1326                 m->m_data += max_linkhdr;
1327                 (void)memcpy(mtod(m, void *), ip, sizeof(struct ip));
1328         } else {
1329                 m->m_data -= optlen;
1330                 m->m_len += optlen;
1331                 m->m_pkthdr.len += optlen;
1332                 ovbcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
1333         }
1334         ip = mtod(m, struct ip *);
1335         bcopy(p->ipopt_list, ip + 1, optlen);
1336         *phlen = sizeof(struct ip) + optlen;
1337         ip->ip_vhl = IP_MAKE_VHL(IPVERSION, *phlen >> 2);
1338         ip->ip_len += optlen;
1339         return (m);
1340 }
1341
1342 /*
1343  * Copy options from ip to jp,
1344  * omitting those not copied during fragmentation.
1345  */
1346 int
1347 ip_optcopy(ip, jp)
1348         struct ip *ip, *jp;
1349 {
1350         u_char *cp, *dp;
1351         int opt, optlen, cnt;
1352
1353         cp = (u_char *)(ip + 1);
1354         dp = (u_char *)(jp + 1);
1355         cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip);
1356         for (; cnt > 0; cnt -= optlen, cp += optlen) {
1357                 opt = cp[0];
1358                 if (opt == IPOPT_EOL)
1359                         break;
1360                 if (opt == IPOPT_NOP) {
1361                         /* Preserve for IP mcast tunnel's LSRR alignment. */
1362                         *dp++ = IPOPT_NOP;
1363                         optlen = 1;
1364                         continue;
1365                 }
1366
1367                 KASSERT(cnt >= IPOPT_OLEN + sizeof(*cp),
1368                     ("ip_optcopy: malformed ipv4 option"));
1369                 optlen = cp[IPOPT_OLEN];
1370                 KASSERT(optlen >= IPOPT_OLEN + sizeof(*cp) && optlen <= cnt,
1371                     ("ip_optcopy: malformed ipv4 option"));
1372
1373                 /* bogus lengths should have been caught by ip_dooptions */
1374                 if (optlen > cnt)
1375                         optlen = cnt;
1376                 if (IPOPT_COPIED(opt)) {
1377                         bcopy(cp, dp, optlen);
1378                         dp += optlen;
1379                 }
1380         }
1381         for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++)
1382                 *dp++ = IPOPT_EOL;
1383         return (optlen);
1384 }
1385
1386 /*
1387  * IP socket option processing.
1388  */
1389 int
1390 ip_ctloutput(so, sopt)
1391         struct socket *so;
1392         struct sockopt *sopt;
1393 {
1394         struct  inpcb *inp = sotoinpcb(so);
1395         int     error, optval;
1396
1397         error = optval = 0;
1398         if (sopt->sopt_level != IPPROTO_IP) {
1399                 return (EINVAL);
1400         }
1401
1402         switch (sopt->sopt_dir) {
1403         case SOPT_SET:
1404                 switch (sopt->sopt_name) {
1405                 case IP_OPTIONS:
1406 #ifdef notyet
1407                 case IP_RETOPTS:
1408 #endif
1409                 {
1410                         struct mbuf *m;
1411                         if (sopt->sopt_valsize > MLEN) {
1412                                 error = EMSGSIZE;
1413                                 break;
1414                         }
1415                         MGET(m, sopt->sopt_td ? MB_WAIT : MB_DONTWAIT, MT_HEADER);
1416                         if (m == 0) {
1417                                 error = ENOBUFS;
1418                                 break;
1419                         }
1420                         m->m_len = sopt->sopt_valsize;
1421                         error = sooptcopyin(sopt, mtod(m, char *), m->m_len,
1422                                             m->m_len);
1423
1424                         return (ip_pcbopts(sopt->sopt_name, &inp->inp_options,
1425                                            m));
1426                 }
1427
1428                 case IP_TOS:
1429                 case IP_TTL:
1430                 case IP_RECVOPTS:
1431                 case IP_RECVRETOPTS:
1432                 case IP_RECVDSTADDR:
1433                 case IP_RECVIF:
1434                 case IP_FAITH:
1435                         error = sooptcopyin(sopt, &optval, sizeof optval,
1436                                             sizeof optval);
1437                         if (error)
1438                                 break;
1439
1440                         switch (sopt->sopt_name) {
1441                         case IP_TOS:
1442                                 inp->inp_ip_tos = optval;
1443                                 break;
1444
1445                         case IP_TTL:
1446                                 inp->inp_ip_ttl = optval;
1447                                 break;
1448 #define OPTSET(bit) \
1449         if (optval) \
1450                 inp->inp_flags |= bit; \
1451         else \
1452                 inp->inp_flags &= ~bit;
1453
1454                         case IP_RECVOPTS:
1455                                 OPTSET(INP_RECVOPTS);
1456                                 break;
1457
1458                         case IP_RECVRETOPTS:
1459                                 OPTSET(INP_RECVRETOPTS);
1460                                 break;
1461
1462                         case IP_RECVDSTADDR:
1463                                 OPTSET(INP_RECVDSTADDR);
1464                                 break;
1465
1466                         case IP_RECVIF:
1467                                 OPTSET(INP_RECVIF);
1468                                 break;
1469
1470                         case IP_FAITH:
1471                                 OPTSET(INP_FAITH);
1472                                 break;
1473                         }
1474                         break;
1475 #undef OPTSET
1476
1477                 case IP_MULTICAST_IF:
1478                 case IP_MULTICAST_VIF:
1479                 case IP_MULTICAST_TTL:
1480                 case IP_MULTICAST_LOOP:
1481                 case IP_ADD_MEMBERSHIP:
1482                 case IP_DROP_MEMBERSHIP:
1483                         error = ip_setmoptions(sopt, &inp->inp_moptions);
1484                         break;
1485
1486                 case IP_PORTRANGE:
1487                         error = sooptcopyin(sopt, &optval, sizeof optval,
1488                                             sizeof optval);
1489                         if (error)
1490                                 break;
1491
1492                         switch (optval) {
1493                         case IP_PORTRANGE_DEFAULT:
1494                                 inp->inp_flags &= ~(INP_LOWPORT);
1495                                 inp->inp_flags &= ~(INP_HIGHPORT);
1496                                 break;
1497
1498                         case IP_PORTRANGE_HIGH:
1499                                 inp->inp_flags &= ~(INP_LOWPORT);
1500                                 inp->inp_flags |= INP_HIGHPORT;
1501                                 break;
1502
1503                         case IP_PORTRANGE_LOW:
1504                                 inp->inp_flags &= ~(INP_HIGHPORT);
1505                                 inp->inp_flags |= INP_LOWPORT;
1506                                 break;
1507
1508                         default:
1509                                 error = EINVAL;
1510                                 break;
1511                         }
1512                         break;
1513
1514 #if defined(IPSEC) || defined(FAST_IPSEC)
1515                 case IP_IPSEC_POLICY:
1516                 {
1517                         caddr_t req;
1518                         size_t len = 0;
1519                         int priv;
1520                         struct mbuf *m;
1521                         int optname;
1522
1523                         if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */
1524                                 break;
1525                         if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */
1526                                 break;
1527                         priv = (sopt->sopt_td != NULL &&
1528                                 suser(sopt->sopt_td) != 0) ? 0 : 1;
1529                         req = mtod(m, caddr_t);
1530                         len = m->m_len;
1531                         optname = sopt->sopt_name;
1532                         error = ipsec4_set_policy(inp, optname, req, len, priv);
1533                         m_freem(m);
1534                         break;
1535                 }
1536 #endif /*IPSEC*/
1537
1538                 default:
1539                         error = ENOPROTOOPT;
1540                         break;
1541                 }
1542                 break;
1543
1544         case SOPT_GET:
1545                 switch (sopt->sopt_name) {
1546                 case IP_OPTIONS:
1547                 case IP_RETOPTS:
1548                         if (inp->inp_options)
1549                                 error = sooptcopyout(sopt,
1550                                                      mtod(inp->inp_options,
1551                                                           char *),
1552                                                      inp->inp_options->m_len);
1553                         else
1554                                 sopt->sopt_valsize = 0;
1555                         break;
1556
1557                 case IP_TOS:
1558                 case IP_TTL:
1559                 case IP_RECVOPTS:
1560                 case IP_RECVRETOPTS:
1561                 case IP_RECVDSTADDR:
1562                 case IP_RECVIF:
1563                 case IP_PORTRANGE:
1564                 case IP_FAITH:
1565                         switch (sopt->sopt_name) {
1566
1567                         case IP_TOS:
1568                                 optval = inp->inp_ip_tos;
1569                                 break;
1570
1571                         case IP_TTL:
1572                                 optval = inp->inp_ip_ttl;
1573                                 break;
1574
1575 #define OPTBIT(bit)     (inp->inp_flags & bit ? 1 : 0)
1576
1577                         case IP_RECVOPTS:
1578                                 optval = OPTBIT(INP_RECVOPTS);
1579                                 break;
1580
1581                         case IP_RECVRETOPTS:
1582                                 optval = OPTBIT(INP_RECVRETOPTS);
1583                                 break;
1584
1585                         case IP_RECVDSTADDR:
1586                                 optval = OPTBIT(INP_RECVDSTADDR);
1587                                 break;
1588
1589                         case IP_RECVIF:
1590                                 optval = OPTBIT(INP_RECVIF);
1591                                 break;
1592
1593                         case IP_PORTRANGE:
1594                                 if (inp->inp_flags & INP_HIGHPORT)
1595                                         optval = IP_PORTRANGE_HIGH;
1596                                 else if (inp->inp_flags & INP_LOWPORT)
1597                                         optval = IP_PORTRANGE_LOW;
1598                                 else
1599                                         optval = 0;
1600                                 break;
1601
1602                         case IP_FAITH:
1603                                 optval = OPTBIT(INP_FAITH);
1604                                 break;
1605                         }
1606                         error = sooptcopyout(sopt, &optval, sizeof optval);
1607                         break;
1608
1609                 case IP_MULTICAST_IF:
1610                 case IP_MULTICAST_VIF:
1611                 case IP_MULTICAST_TTL:
1612                 case IP_MULTICAST_LOOP:
1613                 case IP_ADD_MEMBERSHIP:
1614                 case IP_DROP_MEMBERSHIP:
1615                         error = ip_getmoptions(sopt, inp->inp_moptions);
1616                         break;
1617
1618 #if defined(IPSEC) || defined(FAST_IPSEC)
1619                 case IP_IPSEC_POLICY:
1620                 {
1621                         struct mbuf *m = NULL;
1622                         caddr_t req = NULL;
1623                         size_t len = 0;
1624
1625                         if (m != 0) {
1626                                 req = mtod(m, caddr_t);
1627                                 len = m->m_len;
1628                         }
1629                         error = ipsec4_get_policy(sotoinpcb(so), req, len, &m);
1630                         if (error == 0)
1631                                 error = soopt_mcopyout(sopt, m); /* XXX */
1632                         if (error == 0)
1633                                 m_freem(m);
1634                         break;
1635                 }
1636 #endif /*IPSEC*/
1637
1638                 default:
1639                         error = ENOPROTOOPT;
1640                         break;
1641                 }
1642                 break;
1643         }
1644         return (error);
1645 }
1646
1647 /*
1648  * Set up IP options in pcb for insertion in output packets.
1649  * Store in mbuf with pointer in pcbopt, adding pseudo-option
1650  * with destination address if source routed.
1651  */
1652 static int
1653 ip_pcbopts(optname, pcbopt, m)
1654         int optname;
1655         struct mbuf **pcbopt;
1656         struct mbuf *m;
1657 {
1658         int cnt, optlen;
1659         u_char *cp;
1660         u_char opt;
1661
1662         /* turn off any old options */
1663         if (*pcbopt)
1664                 (void)m_free(*pcbopt);
1665         *pcbopt = 0;
1666         if (m == (struct mbuf *)0 || m->m_len == 0) {
1667                 /*
1668                  * Only turning off any previous options.
1669                  */
1670                 if (m)
1671                         (void)m_free(m);
1672                 return (0);
1673         }
1674
1675         if (m->m_len % sizeof(int32_t))
1676                 goto bad;
1677         /*
1678          * IP first-hop destination address will be stored before
1679          * actual options; move other options back
1680          * and clear it when none present.
1681          */
1682         if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN])
1683                 goto bad;
1684         cnt = m->m_len;
1685         m->m_len += sizeof(struct in_addr);
1686         cp = mtod(m, u_char *) + sizeof(struct in_addr);
1687         ovbcopy(mtod(m, caddr_t), (caddr_t)cp, (unsigned)cnt);
1688         bzero(mtod(m, caddr_t), sizeof(struct in_addr));
1689
1690         for (; cnt > 0; cnt -= optlen, cp += optlen) {
1691                 opt = cp[IPOPT_OPTVAL];
1692                 if (opt == IPOPT_EOL)
1693                         break;
1694                 if (opt == IPOPT_NOP)
1695                         optlen = 1;
1696                 else {
1697                         if (cnt < IPOPT_OLEN + sizeof(*cp))
1698                                 goto bad;
1699                         optlen = cp[IPOPT_OLEN];
1700                         if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt)
1701                                 goto bad;
1702                 }
1703                 switch (opt) {
1704
1705                 default:
1706                         break;
1707
1708                 case IPOPT_LSRR:
1709                 case IPOPT_SSRR:
1710                         /*
1711                          * user process specifies route as:
1712                          *      ->A->B->C->D
1713                          * D must be our final destination (but we can't
1714                          * check that since we may not have connected yet).
1715                          * A is first hop destination, which doesn't appear in
1716                          * actual IP option, but is stored before the options.
1717                          */
1718                         if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr))
1719                                 goto bad;
1720                         m->m_len -= sizeof(struct in_addr);
1721                         cnt -= sizeof(struct in_addr);
1722                         optlen -= sizeof(struct in_addr);
1723                         cp[IPOPT_OLEN] = optlen;
1724                         /*
1725                          * Move first hop before start of options.
1726                          */
1727                         bcopy((caddr_t)&cp[IPOPT_OFFSET+1], mtod(m, caddr_t),
1728                             sizeof(struct in_addr));
1729                         /*
1730                          * Then copy rest of options back
1731                          * to close up the deleted entry.
1732                          */
1733                         ovbcopy((caddr_t)(&cp[IPOPT_OFFSET+1] +
1734                             sizeof(struct in_addr)),
1735                             &cp[IPOPT_OFFSET+1],
1736                             (unsigned)cnt - (IPOPT_MINOFF - 1));
1737                         break;
1738                 }
1739         }
1740         if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr))
1741                 goto bad;
1742         *pcbopt = m;
1743         return (0);
1744
1745 bad:
1746         (void)m_free(m);
1747         return (EINVAL);
1748 }
1749
1750 /*
1751  * XXX
1752  * The whole multicast option thing needs to be re-thought.
1753  * Several of these options are equally applicable to non-multicast
1754  * transmission, and one (IP_MULTICAST_TTL) totally duplicates a
1755  * standard option (IP_TTL).
1756  */
1757
1758 /*
1759  * following RFC1724 section 3.3, 0.0.0.0/8 is interpreted as interface index.
1760  */
1761 static struct ifnet *
1762 ip_multicast_if(a, ifindexp)
1763         struct in_addr *a;
1764         int *ifindexp;
1765 {
1766         int ifindex;
1767         struct ifnet *ifp;
1768
1769         if (ifindexp)
1770                 *ifindexp = 0;
1771         if (ntohl(a->s_addr) >> 24 == 0) {
1772                 ifindex = ntohl(a->s_addr) & 0xffffff;
1773                 if (ifindex < 0 || if_index < ifindex)
1774                         return NULL;
1775                 ifp = ifindex2ifnet[ifindex];
1776                 if (ifindexp)
1777                         *ifindexp = ifindex;
1778         } else {
1779                 INADDR_TO_IFP(*a, ifp);
1780         }
1781         return ifp;
1782 }
1783
1784 /*
1785  * Set the IP multicast options in response to user setsockopt().
1786  */
1787 static int
1788 ip_setmoptions(sopt, imop)
1789         struct sockopt *sopt;
1790         struct ip_moptions **imop;
1791 {
1792         int error = 0;
1793         int i;
1794         struct in_addr addr;
1795         struct ip_mreq mreq;
1796         struct ifnet *ifp;
1797         struct ip_moptions *imo = *imop;
1798         struct route ro;
1799         struct sockaddr_in *dst;
1800         int ifindex;
1801         int s;
1802
1803         if (imo == NULL) {
1804                 /*
1805                  * No multicast option buffer attached to the pcb;
1806                  * allocate one and initialize to default values.
1807                  */
1808                 imo = (struct ip_moptions*)malloc(sizeof(*imo), M_IPMOPTS,
1809                     M_WAITOK);
1810
1811                 if (imo == NULL)
1812                         return (ENOBUFS);
1813                 *imop = imo;
1814                 imo->imo_multicast_ifp = NULL;
1815                 imo->imo_multicast_addr.s_addr = INADDR_ANY;
1816                 imo->imo_multicast_vif = -1;
1817                 imo->imo_multicast_ttl = IP_DEFAULT_MULTICAST_TTL;
1818                 imo->imo_multicast_loop = IP_DEFAULT_MULTICAST_LOOP;
1819                 imo->imo_num_memberships = 0;
1820         }
1821
1822         switch (sopt->sopt_name) {
1823         /* store an index number for the vif you wanna use in the send */
1824         case IP_MULTICAST_VIF:
1825                 if (legal_vif_num == 0) {
1826                         error = EOPNOTSUPP;
1827                         break;
1828                 }
1829                 error = sooptcopyin(sopt, &i, sizeof i, sizeof i);
1830                 if (error)
1831                         break;
1832                 if (!legal_vif_num(i) && (i != -1)) {
1833                         error = EINVAL;
1834                         break;
1835                 }
1836                 imo->imo_multicast_vif = i;
1837                 break;
1838
1839         case IP_MULTICAST_IF:
1840                 /*
1841                  * Select the interface for outgoing multicast packets.
1842                  */
1843                 error = sooptcopyin(sopt, &addr, sizeof addr, sizeof addr);
1844                 if (error)
1845                         break;
1846                 /*
1847                  * INADDR_ANY is used to remove a previous selection.
1848                  * When no interface is selected, a default one is
1849                  * chosen every time a multicast packet is sent.
1850                  */
1851                 if (addr.s_addr == INADDR_ANY) {
1852                         imo->imo_multicast_ifp = NULL;
1853                         break;
1854                 }
1855                 /*
1856                  * The selected interface is identified by its local
1857                  * IP address.  Find the interface and confirm that
1858                  * it supports multicasting.
1859                  */
1860                 s = splimp();
1861                 ifp = ip_multicast_if(&addr, &ifindex);
1862                 if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) {
1863                         splx(s);
1864                         error = EADDRNOTAVAIL;
1865                         break;
1866                 }
1867                 imo->imo_multicast_ifp = ifp;
1868                 if (ifindex)
1869                         imo->imo_multicast_addr = addr;
1870                 else
1871                         imo->imo_multicast_addr.s_addr = INADDR_ANY;
1872                 splx(s);
1873                 break;
1874
1875         case IP_MULTICAST_TTL:
1876                 /*
1877                  * Set the IP time-to-live for outgoing multicast packets.
1878                  * The original multicast API required a char argument,
1879                  * which is inconsistent with the rest of the socket API.
1880                  * We allow either a char or an int.
1881                  */
1882                 if (sopt->sopt_valsize == 1) {
1883                         u_char ttl;
1884                         error = sooptcopyin(sopt, &ttl, 1, 1);
1885                         if (error)
1886                                 break;
1887                         imo->imo_multicast_ttl = ttl;
1888                 } else {
1889                         u_int ttl;
1890                         error = sooptcopyin(sopt, &ttl, sizeof ttl,
1891                                             sizeof ttl);
1892                         if (error)
1893                                 break;
1894                         if (ttl > 255)
1895                                 error = EINVAL;
1896                         else
1897                                 imo->imo_multicast_ttl = ttl;
1898                 }
1899                 break;
1900
1901         case IP_MULTICAST_LOOP:
1902                 /*
1903                  * Set the loopback flag for outgoing multicast packets.
1904                  * Must be zero or one.  The original multicast API required a
1905                  * char argument, which is inconsistent with the rest
1906                  * of the socket API.  We allow either a char or an int.
1907                  */
1908                 if (sopt->sopt_valsize == 1) {
1909                         u_char loop;
1910                         error = sooptcopyin(sopt, &loop, 1, 1);
1911                         if (error)
1912                                 break;
1913                         imo->imo_multicast_loop = !!loop;
1914                 } else {
1915                         u_int loop;
1916                         error = sooptcopyin(sopt, &loop, sizeof loop,
1917                                             sizeof loop);
1918                         if (error)
1919                                 break;
1920                         imo->imo_multicast_loop = !!loop;
1921                 }
1922                 break;
1923
1924         case IP_ADD_MEMBERSHIP:
1925                 /*
1926                  * Add a multicast group membership.
1927                  * Group must be a valid IP multicast address.
1928                  */
1929                 error = sooptcopyin(sopt, &mreq, sizeof mreq, sizeof mreq);
1930                 if (error)
1931                         break;
1932
1933                 if (!IN_MULTICAST(ntohl(mreq.imr_multiaddr.s_addr))) {
1934                         error = EINVAL;
1935                         break;
1936                 }
1937                 s = splimp();
1938                 /*
1939                  * If no interface address was provided, use the interface of
1940                  * the route to the given multicast address.
1941                  */
1942                 if (mreq.imr_interface.s_addr == INADDR_ANY) {
1943                         bzero((caddr_t)&ro, sizeof(ro));
1944                         dst = (struct sockaddr_in *)&ro.ro_dst;
1945                         dst->sin_len = sizeof(*dst);
1946                         dst->sin_family = AF_INET;
1947                         dst->sin_addr = mreq.imr_multiaddr;
1948                         rtalloc(&ro);
1949                         if (ro.ro_rt == NULL) {
1950                                 error = EADDRNOTAVAIL;
1951                                 splx(s);
1952                                 break;
1953                         }
1954                         ifp = ro.ro_rt->rt_ifp;
1955                         rtfree(ro.ro_rt);
1956                 }
1957                 else {
1958                         ifp = ip_multicast_if(&mreq.imr_interface, NULL);
1959                 }
1960
1961                 /*
1962                  * See if we found an interface, and confirm that it
1963                  * supports multicast.
1964                  */
1965                 if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) {
1966                         error = EADDRNOTAVAIL;
1967                         splx(s);
1968                         break;
1969                 }
1970                 /*
1971                  * See if the membership already exists or if all the
1972                  * membership slots are full.
1973                  */
1974                 for (i = 0; i < imo->imo_num_memberships; ++i) {
1975                         if (imo->imo_membership[i]->inm_ifp == ifp &&
1976                             imo->imo_membership[i]->inm_addr.s_addr
1977                                                 == mreq.imr_multiaddr.s_addr)
1978                                 break;
1979                 }
1980                 if (i < imo->imo_num_memberships) {
1981                         error = EADDRINUSE;
1982                         splx(s);
1983                         break;
1984                 }
1985                 if (i == IP_MAX_MEMBERSHIPS) {
1986                         error = ETOOMANYREFS;
1987                         splx(s);
1988                         break;
1989                 }
1990                 /*
1991                  * Everything looks good; add a new record to the multicast
1992                  * address list for the given interface.
1993                  */
1994                 if ((imo->imo_membership[i] =
1995                     in_addmulti(&mreq.imr_multiaddr, ifp)) == NULL) {
1996                         error = ENOBUFS;
1997                         splx(s);
1998                         break;
1999                 }
2000                 ++imo->imo_num_memberships;
2001                 splx(s);
2002                 break;
2003
2004         case IP_DROP_MEMBERSHIP:
2005                 /*
2006                  * Drop a multicast group membership.
2007                  * Group must be a valid IP multicast address.
2008                  */
2009                 error = sooptcopyin(sopt, &mreq, sizeof mreq, sizeof mreq);
2010                 if (error)
2011                         break;
2012
2013                 if (!IN_MULTICAST(ntohl(mreq.imr_multiaddr.s_addr))) {
2014                         error = EINVAL;
2015                         break;
2016                 }
2017
2018                 s = splimp();
2019                 /*
2020                  * If an interface address was specified, get a pointer
2021                  * to its ifnet structure.
2022                  */
2023                 if (mreq.imr_interface.s_addr == INADDR_ANY)
2024                         ifp = NULL;
2025                 else {
2026                         ifp = ip_multicast_if(&mreq.imr_interface, NULL);
2027                         if (ifp == NULL) {
2028                                 error = EADDRNOTAVAIL;
2029                                 splx(s);
2030                                 break;
2031                         }
2032                 }
2033                 /*
2034                  * Find the membership in the membership array.
2035                  */
2036                 for (i = 0; i < imo->imo_num_memberships; ++i) {
2037                         if ((ifp == NULL ||
2038                              imo->imo_membership[i]->inm_ifp == ifp) &&
2039                              imo->imo_membership[i]->inm_addr.s_addr ==
2040                              mreq.imr_multiaddr.s_addr)
2041                                 break;
2042                 }
2043                 if (i == imo->imo_num_memberships) {
2044                         error = EADDRNOTAVAIL;
2045                         splx(s);
2046                         break;
2047                 }
2048                 /*
2049                  * Give up the multicast address record to which the
2050                  * membership points.
2051                  */
2052                 in_delmulti(imo->imo_membership[i]);
2053                 /*
2054                  * Remove the gap in the membership array.
2055                  */
2056                 for (++i; i < imo->imo_num_memberships; ++i)
2057                         imo->imo_membership[i-1] = imo->imo_membership[i];
2058                 --imo->imo_num_memberships;
2059                 splx(s);
2060                 break;
2061
2062         default:
2063                 error = EOPNOTSUPP;
2064                 break;
2065         }
2066
2067         /*
2068          * If all options have default values, no need to keep the mbuf.
2069          */
2070         if (imo->imo_multicast_ifp == NULL &&
2071             imo->imo_multicast_vif == -1 &&
2072             imo->imo_multicast_ttl == IP_DEFAULT_MULTICAST_TTL &&
2073             imo->imo_multicast_loop == IP_DEFAULT_MULTICAST_LOOP &&
2074             imo->imo_num_memberships == 0) {
2075                 free(*imop, M_IPMOPTS);
2076                 *imop = NULL;
2077         }
2078
2079         return (error);
2080 }
2081
2082 /*
2083  * Return the IP multicast options in response to user getsockopt().
2084  */
2085 static int
2086 ip_getmoptions(sopt, imo)
2087         struct sockopt *sopt;
2088         struct ip_moptions *imo;
2089 {
2090         struct in_addr addr;
2091         struct in_ifaddr *ia;
2092         int error, optval;
2093         u_char coptval;
2094
2095         error = 0;
2096         switch (sopt->sopt_name) {
2097         case IP_MULTICAST_VIF:
2098                 if (imo != NULL)
2099                         optval = imo->imo_multicast_vif;
2100                 else
2101                         optval = -1;
2102                 error = sooptcopyout(sopt, &optval, sizeof optval);
2103                 break;
2104
2105         case IP_MULTICAST_IF:
2106                 if (imo == NULL || imo->imo_multicast_ifp == NULL)
2107                         addr.s_addr = INADDR_ANY;
2108                 else if (imo->imo_multicast_addr.s_addr) {
2109                         /* return the value user has set */
2110                         addr = imo->imo_multicast_addr;
2111                 } else {
2112                         IFP_TO_IA(imo->imo_multicast_ifp, ia);
2113                         addr.s_addr = (ia == NULL) ? INADDR_ANY
2114                                 : IA_SIN(ia)->sin_addr.s_addr;
2115                 }
2116                 error = sooptcopyout(sopt, &addr, sizeof addr);
2117                 break;
2118
2119         case IP_MULTICAST_TTL:
2120                 if (imo == 0)
2121                         optval = coptval = IP_DEFAULT_MULTICAST_TTL;
2122                 else
2123                         optval = coptval = imo->imo_multicast_ttl;
2124                 if (sopt->sopt_valsize == 1)
2125                         error = sooptcopyout(sopt, &coptval, 1);
2126                 else
2127                         error = sooptcopyout(sopt, &optval, sizeof optval);
2128                 break;
2129
2130         case IP_MULTICAST_LOOP:
2131                 if (imo == 0)
2132                         optval = coptval = IP_DEFAULT_MULTICAST_LOOP;
2133                 else
2134                         optval = coptval = imo->imo_multicast_loop;
2135                 if (sopt->sopt_valsize == 1)
2136                         error = sooptcopyout(sopt, &coptval, 1);
2137                 else
2138                         error = sooptcopyout(sopt, &optval, sizeof optval);
2139                 break;
2140
2141         default:
2142                 error = ENOPROTOOPT;
2143                 break;
2144         }
2145         return (error);
2146 }
2147
2148 /*
2149  * Discard the IP multicast options.
2150  */
2151 void
2152 ip_freemoptions(imo)
2153         struct ip_moptions *imo;
2154 {
2155         int i;
2156
2157         if (imo != NULL) {
2158                 for (i = 0; i < imo->imo_num_memberships; ++i)
2159                         in_delmulti(imo->imo_membership[i]);
2160                 free(imo, M_IPMOPTS);
2161         }
2162 }
2163
2164 /*
2165  * Routine called from ip_output() to loop back a copy of an IP multicast
2166  * packet to the input queue of a specified interface.  Note that this
2167  * calls the output routine of the loopback "driver", but with an interface
2168  * pointer that might NOT be a loopback interface -- evil, but easier than
2169  * replicating that code here.
2170  */
2171 static void
2172 ip_mloopback(ifp, m, dst, hlen)
2173         struct ifnet *ifp;
2174         struct mbuf *m;
2175         struct sockaddr_in *dst;
2176         int hlen;
2177 {
2178         struct ip *ip;
2179         struct mbuf *copym;
2180
2181         copym = m_copy(m, 0, M_COPYALL);
2182         if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen))
2183                 copym = m_pullup(copym, hlen);
2184         if (copym != NULL) {
2185                 /*
2186                  * if the checksum hasn't been computed, mark it as valid
2187                  */
2188                 if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
2189                         in_delayed_cksum(copym);
2190                         copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
2191                         copym->m_pkthdr.csum_flags |=
2192                             CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
2193                         copym->m_pkthdr.csum_data = 0xffff;
2194                 }
2195                 /*
2196                  * We don't bother to fragment if the IP length is greater
2197                  * than the interface's MTU.  Can this possibly matter?
2198                  */
2199                 ip = mtod(copym, struct ip *);
2200                 ip->ip_len = htons(ip->ip_len);
2201                 ip->ip_off = htons(ip->ip_off);
2202                 ip->ip_sum = 0;
2203                 if (ip->ip_vhl == IP_VHL_BORING) {
2204                         ip->ip_sum = in_cksum_hdr(ip);
2205                 } else {
2206                         ip->ip_sum = in_cksum(copym, hlen);
2207                 }
2208                 /*
2209                  * NB:
2210                  * It's not clear whether there are any lingering
2211                  * reentrancy problems in other areas which might
2212                  * be exposed by using ip_input directly (in
2213                  * particular, everything which modifies the packet
2214                  * in-place).  Yet another option is using the
2215                  * protosw directly to deliver the looped back
2216                  * packet.  For the moment, we'll err on the side
2217                  * of safety by using if_simloop().
2218                  */
2219 #if 1 /* XXX */
2220                 if (dst->sin_family != AF_INET) {
2221                         printf("ip_mloopback: bad address family %d\n",
2222                                                 dst->sin_family);
2223                         dst->sin_family = AF_INET;
2224                 }
2225 #endif
2226
2227 #ifdef notdef
2228                 copym->m_pkthdr.rcvif = ifp;
2229                 ip_input(copym);
2230 #else
2231                 if_simloop(ifp, copym, dst->sin_family, 0);
2232 #endif
2233         }
2234 }