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 1.56 2008/09/07 08:15:25 sephe 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_mbuf_stress_test.h"
  42 #include "opt_mpls.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/thread2.h>
  55 #include <sys/in_cksum.h>
  56
  57 #include <net/if.h>
  58 #include <net/netisr.h>
  59 #include <net/pfil.h>
  60 #include <net/route.h>
  61
  62 #include <netinet/in.h>
  63 #include <netinet/in_systm.h>
  64 #include <netinet/ip.h>
  65 #include <netinet/in_pcb.h>
  66 #include <netinet/in_var.h>
  67 #include <netinet/ip_var.h>
  68 #ifdef IPDIVERT
  69 #include <netinet/ip_divert.h>
  70 #endif
  71
  72 #include <netproto/mpls/mpls_var.h>
  73
  74 static MALLOC_DEFINE(M_IPMOPTS, "ip_moptions", "internet multicast options");
  75
  76 #ifdef IPSEC
  77 #include <netinet6/ipsec.h>
  78 #include <netproto/key/key.h>
  79 #ifdef IPSEC_DEBUG
  80 #include <netproto/key/key_debug.h>
  81 #else
  82 #define KEYDEBUG(lev,arg)
  83 #endif
  84 #endif /*IPSEC*/
  85
  86 #ifdef FAST_IPSEC
  87 #include <netproto/ipsec/ipsec.h>
  88 #include <netproto/ipsec/xform.h>
  89 #include <netproto/ipsec/key.h>
  90 #endif /*FAST_IPSEC*/
  91
  92 #include <net/ipfw/ip_fw.h>
  93 #include <net/dummynet/ip_dummynet.h>
  94
  95 #define print_ip(x, a, y)        kprintf("%s %d.%d.%d.%d%s",\
  96                                 x, (ntohl(a.s_addr)>>24)&0xFF,\
  97                                   (ntohl(a.s_addr)>>16)&0xFF,\
  98                                   (ntohl(a.s_addr)>>8)&0xFF,\
  99                                   (ntohl(a.s_addr))&0xFF, y);
 100
 101 u_short ip_id;
 102
 103 #ifdef MBUF_STRESS_TEST
 104 int mbuf_frag_size = 0;
 105 SYSCTL_INT(_net_inet_ip, OID_AUTO, mbuf_frag_size, CTLFLAG_RW,
 106         &mbuf_frag_size, 0, "Fragment outgoing mbufs to this size");
 107 #endif
 108
 109 static struct mbuf *ip_insertoptions(struct mbuf *, struct mbuf *, int *);
 110 static struct ifnet *ip_multicast_if(struct in_addr *, int *);
 111 static void     ip_mloopback
 112         (struct ifnet *, struct mbuf *, struct sockaddr_in *, int);
 113 static int      ip_getmoptions
 114         (struct sockopt *, struct ip_moptions *);
 115 static int      ip_pcbopts(int, struct mbuf **, struct mbuf *);
 116 static int      ip_setmoptions
 117         (struct sockopt *, struct ip_moptions **);
 118
 119 int     ip_optcopy(struct ip *, struct ip *);
 120
 121
 122 extern  struct protosw inetsw[];
 123
 124 /*
 125  * IP output.  The packet in mbuf chain m contains a skeletal IP
 126  * header (with len, off, ttl, proto, tos, src, dst).
 127  * The mbuf chain containing the packet will be freed.
 128  * The mbuf opt, if present, will not be freed.
 129  */
 130 int
 131 ip_output(struct mbuf *m0, struct mbuf *opt, struct route *ro,
 132           int flags, struct ip_moptions *imo, struct inpcb *inp)
 133 {
 134         struct ip *ip;
 135         struct ifnet *ifp = NULL;       /* keep compiler happy */
 136         struct mbuf *m;
 137         int hlen = sizeof(struct ip);
 138         int len, off, error = 0;
 139         struct sockaddr_in *dst = NULL; /* keep compiler happy */
 140         struct in_ifaddr *ia = NULL;
 141         int isbroadcast, sw_csum;
 142         struct in_addr pkt_dst;
 143         struct route iproute;
 144         struct m_tag *mtag;
 145 #ifdef IPSEC
 146         struct secpolicy *sp = NULL;
 147         struct socket *so = inp ? inp->inp_socket : NULL;
 148 #endif
 149 #ifdef FAST_IPSEC
 150         struct secpolicy *sp = NULL;
 151         struct tdb_ident *tdbi;
 152 #endif /* FAST_IPSEC */
 153         struct sockaddr_in *next_hop = NULL;
 154         int src_was_INADDR_ANY = 0;     /* as the name says... */
 155
 156         m = m0;
 157         M_ASSERTPKTHDR(m);
 158
 159         if (ro == NULL) {
 160                 ro = &iproute;
 161                 bzero(ro, sizeof *ro);
 162         }
 163
 164         if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) {
 165                 /* Next hop */
 166                 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
 167                 KKASSERT(mtag != NULL);
 168                 next_hop = m_tag_data(mtag);
 169         }
 170
 171         if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) {
 172                 struct dn_pkt *dn_pkt;
 173
 174                 /* Extract info from dummynet tag */
 175                 mtag = m_tag_find(m, PACKET_TAG_DUMMYNET, NULL);
 176                 KKASSERT(mtag != NULL);
 177                 dn_pkt = m_tag_data(mtag);
 178
 179                 /*
 180                  * The packet was already tagged, so part of the
 181                  * processing was already done, and we need to go down.
 182                  * Get the calculated parameters from the tag.
 183                  */
 184                 ifp = dn_pkt->ifp;
 185
 186                 KKASSERT(ro == &iproute);
 187                 *ro = dn_pkt->ro; /* structure copy */
 188
 189                 dst = dn_pkt->dn_dst;
 190                 if (dst == (struct sockaddr_in *)&(dn_pkt->ro.ro_dst)) {
 191                         /* If 'dst' points into dummynet tag, adjust it */
 192                         dst = (struct sockaddr_in *)&(ro->ro_dst);
 193                 }
 194
 195                 ip = mtod(m, struct ip *);
 196                 hlen = IP_VHL_HL(ip->ip_vhl) << 2 ;
 197                 if (ro->ro_rt)
 198                         ia = ifatoia(ro->ro_rt->rt_ifa);
 199                 goto sendit;
 200         }
 201
 202         if (opt) {
 203                 len = 0;
 204                 m = ip_insertoptions(m, opt, &len);
 205                 if (len != 0)
 206                         hlen = len;
 207         }
 208         ip = mtod(m, struct ip *);
 209         pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst;
 210
 211         /*
 212          * Fill in IP header.
 213          */
 214         if (!(flags & (IP_FORWARDING|IP_RAWOUTPUT))) {
 215                 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, hlen >> 2);
 216                 ip->ip_off &= IP_DF;
 217                 ip->ip_id = ip_newid();
 218                 ipstat.ips_localout++;
 219         } else {
 220                 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 221         }
 222
 223         dst = (struct sockaddr_in *)&ro->ro_dst;
 224         /*
 225          * If there is a cached route,
 226          * check that it is to the same destination
 227          * and is still up.  If not, free it and try again.
 228          * The address family should also be checked in case of sharing the
 229          * cache with IPv6.
 230          */
 231         if (ro->ro_rt &&
 232             (!(ro->ro_rt->rt_flags & RTF_UP) ||
 233              dst->sin_family != AF_INET ||
 234              dst->sin_addr.s_addr != pkt_dst.s_addr)) {
 235                 rtfree(ro->ro_rt);
 236                 ro->ro_rt = (struct rtentry *)NULL;
 237         }
 238         if (ro->ro_rt == NULL) {
 239                 bzero(dst, sizeof *dst);
 240                 dst->sin_family = AF_INET;
 241                 dst->sin_len = sizeof *dst;
 242                 dst->sin_addr = pkt_dst;
 243         }
 244         /*
 245          * If routing to interface only,
 246          * short circuit routing lookup.
 247          */
 248         if (flags & IP_ROUTETOIF) {
 249                 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL &&
 250                     (ia = ifatoia(ifa_ifwithnet(sintosa(dst)))) == NULL) {
 251                         ipstat.ips_noroute++;
 252                         error = ENETUNREACH;
 253                         goto bad;
 254                 }
 255                 ifp = ia->ia_ifp;
 256                 ip->ip_ttl = 1;
 257                 isbroadcast = in_broadcast(dst->sin_addr, ifp);
 258         } else if (IN_MULTICAST(ntohl(pkt_dst.s_addr)) &&
 259                    imo != NULL && imo->imo_multicast_ifp != NULL) {
 260                 /*
 261                  * Bypass the normal routing lookup for multicast
 262                  * packets if the interface is specified.
 263                  */
 264                 ifp = imo->imo_multicast_ifp;
 265                 ia = IFP_TO_IA(ifp);
 266                 isbroadcast = 0;        /* fool gcc */
 267         } else {
 268                 /*
 269                  * If this is the case, we probably don't want to allocate
 270                  * a protocol-cloned route since we didn't get one from the
 271                  * ULP.  This lets TCP do its thing, while not burdening
 272                  * forwarding or ICMP with the overhead of cloning a route.
 273                  * Of course, we still want to do any cloning requested by
 274                  * the link layer, as this is probably required in all cases
 275                  * for correct operation (as it is for ARP).
 276                  */
 277                 if (ro->ro_rt == NULL)
 278                         rtalloc_ign(ro, RTF_PRCLONING);
 279                 if (ro->ro_rt == NULL) {
 280                         ipstat.ips_noroute++;
 281                         error = EHOSTUNREACH;
 282                         goto bad;
 283                 }
 284                 ia = ifatoia(ro->ro_rt->rt_ifa);
 285                 ifp = ro->ro_rt->rt_ifp;
 286                 ro->ro_rt->rt_use++;
 287                 if (ro->ro_rt->rt_flags & RTF_GATEWAY)
 288                         dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway;
 289                 if (ro->ro_rt->rt_flags & RTF_HOST)
 290                         isbroadcast = (ro->ro_rt->rt_flags & RTF_BROADCAST);
 291                 else
 292                         isbroadcast = in_broadcast(dst->sin_addr, ifp);
 293         }
 294         if (IN_MULTICAST(ntohl(pkt_dst.s_addr))) {
 295                 struct in_multi *inm;
 296
 297                 m->m_flags |= M_MCAST;
 298                 /*
 299                  * IP destination address is multicast.  Make sure "dst"
 300                  * still points to the address in "ro".  (It may have been
 301                  * changed to point to a gateway address, above.)
 302                  */
 303                 dst = (struct sockaddr_in *)&ro->ro_dst;
 304                 /*
 305                  * See if the caller provided any multicast options
 306                  */
 307                 if (imo != NULL) {
 308                         ip->ip_ttl = imo->imo_multicast_ttl;
 309                         if (imo->imo_multicast_vif != -1)
 310                                 ip->ip_src.s_addr =
 311                                     ip_mcast_src ?
 312                                     ip_mcast_src(imo->imo_multicast_vif) :
 313                                     INADDR_ANY;
 314                 } else
 315                         ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL;
 316                 /*
 317                  * Confirm that the outgoing interface supports multicast.
 318                  */
 319                 if ((imo == NULL) || (imo->imo_multicast_vif == -1)) {
 320                         if (!(ifp->if_flags & IFF_MULTICAST)) {
 321                                 ipstat.ips_noroute++;
 322                                 error = ENETUNREACH;
 323                                 goto bad;
 324                         }
 325                 }
 326                 /*
 327                  * If source address not specified yet, use address
 328                  * of outgoing interface.
 329                  */
 330                 if (ip->ip_src.s_addr == INADDR_ANY) {
 331                         /* Interface may have no addresses. */
 332                         if (ia != NULL)
 333                                 ip->ip_src = IA_SIN(ia)->sin_addr;
 334                 }
 335
 336                 IN_LOOKUP_MULTI(pkt_dst, ifp, inm);
 337                 if (inm != NULL &&
 338                    (imo == NULL || imo->imo_multicast_loop)) {
 339                         /*
 340                          * If we belong to the destination multicast group
 341                          * on the outgoing interface, and the caller did not
 342                          * forbid loopback, loop back a copy.
 343                          */
 344                         ip_mloopback(ifp, m, dst, hlen);
 345                 }
 346                 else {
 347                         /*
 348                          * If we are acting as a multicast router, perform
 349                          * multicast forwarding as if the packet had just
 350                          * arrived on the interface to which we are about
 351                          * to send.  The multicast forwarding function
 352                          * recursively calls this function, using the
 353                          * IP_FORWARDING flag to prevent infinite recursion.
 354                          *
 355                          * Multicasts that are looped back by ip_mloopback(),
 356                          * above, will be forwarded by the ip_input() routine,
 357                          * if necessary.
 358                          */
 359                         if (ip_mrouter && !(flags & IP_FORWARDING)) {
 360                                 /*
 361                                  * If rsvp daemon is not running, do not
 362                                  * set ip_moptions. This ensures that the packet
 363                                  * is multicast and not just sent down one link
 364                                  * as prescribed by rsvpd.
 365                                  */
 366                                 if (!rsvp_on)
 367                                         imo = NULL;
 368                                 if (ip_mforward &&
 369                                     ip_mforward(ip, ifp, m, imo) != 0) {
 370                                         m_freem(m);
 371                                         goto done;
 372                                 }
 373                         }
 374                 }
 375
 376                 /*
 377                  * Multicasts with a time-to-live of zero may be looped-
 378                  * back, above, but must not be transmitted on a network.
 379                  * Also, multicasts addressed to the loopback interface
 380                  * are not sent -- the above call to ip_mloopback() will
 381                  * loop back a copy if this host actually belongs to the
 382                  * destination group on the loopback interface.
 383                  */
 384                 if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) {
 385                         m_freem(m);
 386                         goto done;
 387                 }
 388
 389                 goto sendit;
 390         } else {
 391                 m->m_flags &= ~M_MCAST;
 392         }
 393 #ifndef notdef
 394         /*
 395          * If the source address is not specified yet, use the address
 396          * of the outoing interface. In case, keep note we did that, so
 397          * if the the firewall changes the next-hop causing the output
 398          * interface to change, we can fix that.
 399          */
 400         if (ip->ip_src.s_addr == INADDR_ANY) {
 401                 /* Interface may have no addresses. */
 402                 if (ia != NULL) {
 403                         ip->ip_src = IA_SIN(ia)->sin_addr;
 404                         src_was_INADDR_ANY = 1;
 405                 }
 406         }
 407 #endif /* notdef */
 408 #ifdef ALTQ
 409         /*
 410          * Disable packet drop hack.
 411          * Packetdrop should be done by queueing.
 412          */
 413 #else /* !ALTQ */
 414         /*
 415          * Verify that we have any chance at all of being able to queue
 416          *      the packet or packet fragments
 417          */
 418         if ((ifp->if_snd.ifq_len + ip->ip_len / ifp->if_mtu + 1) >=
 419                 ifp->if_snd.ifq_maxlen) {
 420                         error = ENOBUFS;
 421                         ipstat.ips_odropped++;
 422                         goto bad;
 423         }
 424 #endif /* !ALTQ */
 425
 426         /*
 427          * Look for broadcast address and
 428          * verify user is allowed to send
 429          * such a packet.
 430          */
 431         if (isbroadcast) {
 432                 if (!(ifp->if_flags & IFF_BROADCAST)) {
 433                         error = EADDRNOTAVAIL;
 434                         goto bad;
 435                 }
 436                 if (!(flags & IP_ALLOWBROADCAST)) {
 437                         error = EACCES;
 438                         goto bad;
 439                 }
 440                 /* don't allow broadcast messages to be fragmented */
 441                 if (ip->ip_len > ifp->if_mtu) {
 442                         error = EMSGSIZE;
 443                         goto bad;
 444                 }
 445                 m->m_flags |= M_BCAST;
 446         } else {
 447                 m->m_flags &= ~M_BCAST;
 448         }
 449
 450 sendit:
 451 #ifdef IPSEC
 452         /* get SP for this packet */
 453         if (so == NULL)
 454                 sp = ipsec4_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, flags, &error);
 455         else
 456                 sp = ipsec4_getpolicybysock(m, IPSEC_DIR_OUTBOUND, so, &error);
 457
 458         if (sp == NULL) {
 459                 ipsecstat.out_inval++;
 460                 goto bad;
 461         }
 462
 463         error = 0;
 464
 465         /* check policy */
 466         switch (sp->policy) {
 467         case IPSEC_POLICY_DISCARD:
 468                 /*
 469                  * This packet is just discarded.
 470                  */
 471                 ipsecstat.out_polvio++;
 472                 goto bad;
 473
 474         case IPSEC_POLICY_BYPASS:
 475         case IPSEC_POLICY_NONE:
 476                 /* no need to do IPsec. */
 477                 goto skip_ipsec;
 478
 479         case IPSEC_POLICY_IPSEC:
 480                 if (sp->req == NULL) {
 481                         /* acquire a policy */
 482                         error = key_spdacquire(sp);
 483                         goto bad;
 484                 }
 485                 break;
 486
 487         case IPSEC_POLICY_ENTRUST:
 488         default:
 489                 kprintf("ip_output: Invalid policy found. %d\n", sp->policy);
 490         }
 491     {
 492         struct ipsec_output_state state;
 493         bzero(&state, sizeof state);
 494         state.m = m;
 495         if (flags & IP_ROUTETOIF) {
 496                 state.ro = &iproute;
 497                 bzero(&iproute, sizeof iproute);
 498         } else
 499                 state.ro = ro;
 500         state.dst = (struct sockaddr *)dst;
 501
 502         ip->ip_sum = 0;
 503
 504         /*
 505          * XXX
 506          * delayed checksums are not currently compatible with IPsec
 507          */
 508         if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 509                 in_delayed_cksum(m);
 510                 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
 511         }
 512
 513         ip->ip_len = htons(ip->ip_len);
 514         ip->ip_off = htons(ip->ip_off);
 515
 516         error = ipsec4_output(&state, sp, flags);
 517
 518         m = state.m;
 519         if (flags & IP_ROUTETOIF) {
 520                 /*
 521                  * if we have tunnel mode SA, we may need to ignore
 522                  * IP_ROUTETOIF.
 523                  */
 524                 if (state.ro != &iproute || state.ro->ro_rt != NULL) {
 525                         flags &= ~IP_ROUTETOIF;
 526                         ro = state.ro;
 527                 }
 528         } else
 529                 ro = state.ro;
 530         dst = (struct sockaddr_in *)state.dst;
 531         if (error) {
 532                 /* mbuf is already reclaimed in ipsec4_output. */
 533                 m0 = NULL;
 534                 switch (error) {
 535                 case EHOSTUNREACH:
 536                 case ENETUNREACH:
 537                 case EMSGSIZE:
 538                 case ENOBUFS:
 539                 case ENOMEM:
 540                         break;
 541                 default:
 542                         kprintf("ip4_output (ipsec): error code %d\n", error);
 543                         /*fall through*/
 544                 case ENOENT:
 545                         /* don't show these error codes to the user */
 546                         error = 0;
 547                         break;
 548                 }
 549                 goto bad;
 550         }
 551     }
 552
 553         /* be sure to update variables that are affected by ipsec4_output() */
 554         ip = mtod(m, struct ip *);
 555 #ifdef _IP_VHL
 556         hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 557 #else
 558         hlen = ip->ip_hl << 2;
 559 #endif
 560         if (ro->ro_rt == NULL) {
 561                 if (!(flags & IP_ROUTETOIF)) {
 562                         kprintf("ip_output: "
 563                                 "can't update route after IPsec processing\n");
 564                         error = EHOSTUNREACH;   /*XXX*/
 565                         goto bad;
 566                 }
 567         } else {
 568                 ia = ifatoia(ro->ro_rt->rt_ifa);
 569                 ifp = ro->ro_rt->rt_ifp;
 570         }
 571
 572         /* make it flipped, again. */
 573         ip->ip_len = ntohs(ip->ip_len);
 574         ip->ip_off = ntohs(ip->ip_off);
 575 skip_ipsec:
 576 #endif /*IPSEC*/
 577 #ifdef FAST_IPSEC
 578         /*
 579          * Check the security policy (SP) for the packet and, if
 580          * required, do IPsec-related processing.  There are two
 581          * cases here; the first time a packet is sent through
 582          * it will be untagged and handled by ipsec4_checkpolicy.
 583          * If the packet is resubmitted to ip_output (e.g. after
 584          * AH, ESP, etc. processing), there will be a tag to bypass
 585          * the lookup and related policy checking.
 586          */
 587         mtag = m_tag_find(m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
 588         crit_enter();
 589         if (mtag != NULL) {
 590                 tdbi = (struct tdb_ident *)m_tag_data(mtag);
 591                 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
 592                 if (sp == NULL)
 593                         error = -EINVAL;        /* force silent drop */
 594                 m_tag_delete(m, mtag);
 595         } else {
 596                 sp = ipsec4_checkpolicy(m, IPSEC_DIR_OUTBOUND, flags,
 597                                         &error, inp);
 598         }
 599         /*
 600          * There are four return cases:
 601          *    sp != NULL                    apply IPsec policy
 602          *    sp == NULL, error == 0        no IPsec handling needed
 603          *    sp == NULL, error == -EINVAL  discard packet w/o error
 604          *    sp == NULL, error != 0        discard packet, report error
 605          */
 606         if (sp != NULL) {
 607                 /* Loop detection, check if ipsec processing already done */
 608                 KASSERT(sp->req != NULL, ("ip_output: no ipsec request"));
 609                 for (mtag = m_tag_first(m); mtag != NULL;
 610                      mtag = m_tag_next(m, mtag)) {
 611                         if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
 612                                 continue;
 613                         if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
 614                             mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
 615                                 continue;
 616                         /*
 617                          * Check if policy has an SA associated with it.
 618                          * This can happen when an SP has yet to acquire
 619                          * an SA; e.g. on first reference.  If it occurs,
 620                          * then we let ipsec4_process_packet do its thing.
 621                          */
 622                         if (sp->req->sav == NULL)
 623                                 break;
 624                         tdbi = (struct tdb_ident *)m_tag_data(mtag);
 625                         if (tdbi->spi == sp->req->sav->spi &&
 626                             tdbi->proto == sp->req->sav->sah->saidx.proto &&
 627                             bcmp(&tdbi->dst, &sp->req->sav->sah->saidx.dst,
 628                                  sizeof(union sockaddr_union)) == 0) {
 629                                 /*
 630                                  * No IPsec processing is needed, free
 631                                  * reference to SP.
 632                                  *
 633                                  * NB: null pointer to avoid free at
 634                                  *     done: below.
 635                                  */
 636                                 KEY_FREESP(&sp), sp = NULL;
 637                                 crit_exit();
 638                                 goto spd_done;
 639                         }
 640                 }
 641
 642                 /*
 643                  * Do delayed checksums now because we send before
 644                  * this is done in the normal processing path.
 645                  */
 646                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 647                         in_delayed_cksum(m);
 648                         m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
 649                 }
 650
 651                 ip->ip_len = htons(ip->ip_len);
 652                 ip->ip_off = htons(ip->ip_off);
 653
 654                 /* NB: callee frees mbuf */
 655                 error = ipsec4_process_packet(m, sp->req, flags, 0);
 656                 /*
 657                  * Preserve KAME behaviour: ENOENT can be returned
 658                  * when an SA acquire is in progress.  Don't propagate
 659                  * this to user-level; it confuses applications.
 660                  *
 661                  * XXX this will go away when the SADB is redone.
 662                  */
 663                 if (error == ENOENT)
 664                         error = 0;
 665                 crit_exit();
 666                 goto done;
 667         } else {
 668                 crit_exit();
 669
 670                 if (error != 0) {
 671                         /*
 672                          * Hack: -EINVAL is used to signal that a packet
 673                          * should be silently discarded.  This is typically
 674                          * because we asked key management for an SA and
 675                          * it was delayed (e.g. kicked up to IKE).
 676                          */
 677                         if (error == -EINVAL)
 678                                 error = 0;
 679                         goto bad;
 680                 } else {
 681                         /* No IPsec processing for this packet. */
 682                 }
 683 #ifdef notyet
 684                 /*
 685                  * If deferred crypto processing is needed, check that
 686                  * the interface supports it.
 687                  */
 688                 mtag = m_tag_find(m, PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED, NULL);
 689                 if (mtag != NULL && !(ifp->if_capenable & IFCAP_IPSEC)) {
 690                         /* notify IPsec to do its own crypto */
 691                         ipsp_skipcrypto_unmark((struct tdb_ident *)m_tag_data(mtag));
 692                         error = EHOSTUNREACH;
 693                         goto bad;
 694                 }
 695 #endif
 696         }
 697 spd_done:
 698 #endif /* FAST_IPSEC */
 699         /*
 700          * IpHack's section.
 701          * - Xlate: translate packet's addr/port (NAT).
 702          * - Firewall: deny/allow/etc.
 703          * - Wrap: fake packet's addr/port <unimpl.>
 704          * - Encapsulate: put it in another IP and send out. <unimp.>
 705          */
 706
 707         /*
 708          * Run through list of hooks for output packets.
 709          */
 710         if (pfil_has_hooks(&inet_pfil_hook)) {
 711                 error = pfil_run_hooks(&inet_pfil_hook, &m, ifp, PFIL_OUT);
 712                 if (error != 0 || m == NULL)
 713                         goto done;
 714                 ip = mtod(m, struct ip *);
 715         }
 716
 717         /*
 718          * Check with the firewall...
 719          * but not if we are already being fwd'd from a firewall.
 720          */
 721         if (fw_enable && IPFW_LOADED && !next_hop) {
 722                 struct sockaddr_in *old = dst;
 723                 struct ip_fw_args args;
 724
 725                 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) {
 726                         /* Extract info from dummynet tag */
 727                         mtag = m_tag_find(m, PACKET_TAG_DUMMYNET, NULL);
 728                         KKASSERT(mtag != NULL);
 729                         args.rule =
 730                         ((struct dn_pkt *)m_tag_data(mtag))->dn_priv;
 731                         KKASSERT(args.rule != NULL);
 732
 733                         m_tag_delete(m, mtag);
 734                         m->m_pkthdr.fw_flags &= ~DUMMYNET_MBUF_TAGGED;
 735                 } else {
 736                         args.rule = NULL;
 737                 }
 738
 739                 args.eh = NULL;
 740                 args.m = m;
 741                 args.oif = ifp;
 742                 off = ip_fw_chk_ptr(&args);
 743                 m = args.m;
 744
 745                 if (m == NULL) {
 746                         error = EACCES;
 747                         goto done;
 748                 }
 749                 ip = mtod(m, struct ip *);
 750
 751                 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) {
 752                         mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
 753                         KKASSERT(mtag != NULL);
 754                         next_hop = m_tag_data(mtag);
 755                         dst = next_hop;
 756                 }
 757
 758                 /*
 759                  * On return we must do the following:
 760                  * (off & IP_FW_PORT_DENY_FLAG) -> drop the pkt (new interface)
 761                  * 1<=off<= 0xffff              -> DIVERT
 762                  * (off & IP_FW_PORT_DYNT_FLAG) -> send to a DUMMYNET pipe
 763                  * (off & IP_FW_PORT_TEE_FLAG)  -> TEE the packet
 764                  * dst != old                   -> IPFIREWALL_FORWARD
 765                  * off==0, dst==old             -> accept
 766                  * If some of the above modules are not compiled in, then
 767                  * we should't have to check the corresponding condition
 768                  * (because the ipfw control socket should not accept
 769                  * unsupported rules), but better play safe and drop
 770                  * packets in case of doubt.
 771                  */
 772                 if (off & IP_FW_PORT_DENY_FLAG) {
 773                         m_freem(m);
 774                         error = EACCES;
 775                         goto done;
 776                 }
 777                 if (off == 0 && dst == old)             /* common case */
 778                         goto pass;
 779                 if (off & IP_FW_PORT_DYNT_FLAG) {
 780                         /*
 781                          * pass the pkt to dummynet. Need to include
 782                          * pipe number, m, ifp, ro, dst because these are
 783                          * not recomputed in the next pass.
 784                          * All other parameters have been already used and
 785                          * so they are not needed anymore.
 786                          * XXX note: if the ifp or ro entry are deleted
 787                          * while a pkt is in dummynet, we are in trouble!
 788                          */
 789                         args.ro = ro;
 790                         args.dst = dst;
 791                         args.flags = flags;
 792
 793                         error = 0;
 794                         ip_fw_dn_io_ptr(m, off & 0xffff, DN_TO_IP_OUT, &args);
 795                         goto done;
 796                 }
 797 #ifdef IPDIVERT
 798                 if (off != 0 && !(off & IP_FW_PORT_DYNT_FLAG)) {
 799                         struct mbuf *clone = NULL;
 800
 801                         /* Clone packet if we're doing a 'tee' */
 802                         if ((off & IP_FW_PORT_TEE_FLAG))
 803                                 clone = m_dup(m, MB_DONTWAIT);
 804
 805                         /*
 806                          * XXX
 807                          * delayed checksums are not currently compatible
 808                          * with divert sockets.
 809                          */
 810                         if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 811                                 in_delayed_cksum(m);
 812                                 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
 813                         }
 814
 815                         /* Restore packet header fields to original values */
 816                         ip->ip_len = htons(ip->ip_len);
 817                         ip->ip_off = htons(ip->ip_off);
 818
 819                         /* Deliver packet to divert input routine */
 820                         divert_packet(m, 0);
 821
 822                         /* If 'tee', continue with original packet */
 823                         if (clone != NULL) {
 824                                 m = clone;
 825                                 ip = mtod(m, struct ip *);
 826                                 goto pass;
 827                         }
 828                         goto done;
 829                 }
 830 #endif
 831
 832                 /* IPFIREWALL_FORWARD */
 833                 /*
 834                  * Check dst to make sure it is directly reachable on the
 835                  * interface we previously thought it was.
 836                  * If it isn't (which may be likely in some situations) we have
 837                  * to re-route it (ie, find a route for the next-hop and the
 838                  * associated interface) and set them here. This is nested
 839                  * forwarding which in most cases is undesirable, except where
 840                  * such control is nigh impossible. So we do it here.
 841                  * And I'm babbling.
 842                  */
 843                 if (off == 0 && old != dst) { /* FORWARD, dst has changed */
 844 #if 0
 845                         /*
 846                          * XXX To improve readability, this block should be
 847                          * changed into a function call as below:
 848                          */
 849                         error = ip_ipforward(&m, &dst, &ifp);
 850                         if (error)
 851                                 goto bad;
 852                         if (m == NULL) /* ip_input consumed the mbuf */
 853                                 goto done;
 854 #else
 855                         struct in_ifaddr *ia;
 856                         struct in_ifaddr_container *iac;
 857
 858                         /*
 859                          * XXX sro_fwd below is static, and a pointer
 860                          * to it gets passed to routines downstream.
 861                          * This could have surprisingly bad results in
 862                          * practice, because its content is overwritten
 863                          * by subsequent packets.
 864                          */
 865                         /* There must be a better way to do this next line... */
 866                         static struct route sro_fwd;
 867                         struct route *ro_fwd = &sro_fwd;
 868
 869 #if 0
 870                         print_ip("IPFIREWALL_FORWARD: New dst ip: ",
 871                             dst->sin_addr, "\n");
 872 #endif
 873
 874                         /*
 875                          * We need to figure out if we have been forwarded
 876                          * to a local socket. If so, then we should somehow
 877                          * "loop back" to ip_input, and get directed to the
 878                          * PCB as if we had received this packet. This is
 879                          * because it may be dificult to identify the packets
 880                          * you want to forward until they are being output
 881                          * and have selected an interface. (e.g. locally
 882                          * initiated packets) If we used the loopback inteface,
 883                          * we would not be able to control what happens
 884                          * as the packet runs through ip_input() as
 885                          * it is done through a ISR.
 886                          */
 887                         ia = NULL;
 888                         LIST_FOREACH(iac, INADDR_HASH(dst->sin_addr.s_addr),
 889                                      ia_hash) {
 890                                 /*
 891                                  * If the addr to forward to is one
 892                                  * of ours, we pretend to
 893                                  * be the destination for this packet.
 894                                  */
 895                                 if (IA_SIN(iac->ia)->sin_addr.s_addr ==
 896                                     dst->sin_addr.s_addr) {
 897                                         ia = iac->ia;
 898                                         break;
 899                                 }
 900                         }
 901                         if (ia != NULL) {    /* tell ip_input "dont filter" */
 902                                 if (m->m_pkthdr.rcvif == NULL)
 903                                         m->m_pkthdr.rcvif = ifunit("lo0");
 904                                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 905                                         m->m_pkthdr.csum_flags |=
 906                                             CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
 907                                         m->m_pkthdr.csum_data = 0xffff;
 908                                 }
 909                                 m->m_pkthdr.csum_flags |=
 910                                     CSUM_IP_CHECKED | CSUM_IP_VALID;
 911                                 ip->ip_len = htons(ip->ip_len);
 912                                 ip->ip_off = htons(ip->ip_off);
 913                                 ip_input(m);
 914                                 goto done;
 915                         }
 916                         /* Some of the logic for this was nicked from above.
 917                          *
 918                          * This rewrites the cached route in a local PCB.
 919                          * Is this what we want to do?
 920                          */
 921                         bcopy(dst, &ro_fwd->ro_dst, sizeof *dst);
 922                         ro_fwd->ro_rt = NULL;
 923
 924                         rtalloc_ign(ro_fwd, RTF_PRCLONING);
 925                         if (ro_fwd->ro_rt == NULL) {
 926                                 ipstat.ips_noroute++;
 927                                 error = EHOSTUNREACH;
 928                                 goto bad;
 929                         }
 930
 931                         ia = ifatoia(ro_fwd->ro_rt->rt_ifa);
 932                         ifp = ro_fwd->ro_rt->rt_ifp;
 933                         ro_fwd->ro_rt->rt_use++;
 934                         if (ro_fwd->ro_rt->rt_flags & RTF_GATEWAY)
 935                                 dst = (struct sockaddr_in *)
 936                                     ro_fwd->ro_rt->rt_gateway;
 937                         if (ro_fwd->ro_rt->rt_flags & RTF_HOST)
 938                                 isbroadcast =
 939                                     (ro_fwd->ro_rt->rt_flags & RTF_BROADCAST);
 940                         else
 941                                 isbroadcast = in_broadcast(dst->sin_addr, ifp);
 942                         if (ro->ro_rt != NULL)
 943                                 rtfree(ro->ro_rt);
 944                         ro->ro_rt = ro_fwd->ro_rt;
 945                         dst = (struct sockaddr_in *)&ro_fwd->ro_dst;
 946
 947 #endif  /* ... block to be put into a function */
 948                         /*
 949                          * If we added a default src ip earlier,
 950                          * which would have been gotten from the-then
 951                          * interface, do it again, from the new one.
 952                          */
 953                         if (src_was_INADDR_ANY)
 954                                 ip->ip_src = IA_SIN(ia)->sin_addr;
 955                         goto pass ;
 956                 }
 957
 958                 /*
 959                  * if we get here, none of the above matches, and
 960                  * we have to drop the pkt
 961                  */
 962                 m_freem(m);
 963                 error = EACCES; /* not sure this is the right error msg */
 964                 goto done;
 965         }
 966
 967 pass:
 968         /* 127/8 must not appear on wire - RFC1122. */
 969         if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
 970             (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
 971                 if (!(ifp->if_flags & IFF_LOOPBACK)) {
 972                         ipstat.ips_badaddr++;
 973                         error = EADDRNOTAVAIL;
 974                         goto bad;
 975                 }
 976         }
 977
 978         m->m_pkthdr.csum_flags |= CSUM_IP;
 979         sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_hwassist;
 980         if (sw_csum & CSUM_DELAY_DATA) {
 981                 in_delayed_cksum(m);
 982                 sw_csum &= ~CSUM_DELAY_DATA;
 983         }
 984         m->m_pkthdr.csum_flags &= ifp->if_hwassist;
 985
 986         /*
 987          * If small enough for interface, or the interface will take
 988          * care of the fragmentation for us, can just send directly.
 989          */
 990         if (ip->ip_len <= ifp->if_mtu || ((ifp->if_hwassist & CSUM_FRAGMENT) &&
 991             !(ip->ip_off & IP_DF))) {
 992                 ip->ip_len = htons(ip->ip_len);
 993                 ip->ip_off = htons(ip->ip_off);
 994                 ip->ip_sum = 0;
 995                 if (sw_csum & CSUM_DELAY_IP) {
 996                         if (ip->ip_vhl == IP_VHL_BORING) {
 997                                 ip->ip_sum = in_cksum_hdr(ip);
 998                         } else {
 999                                 ip->ip_sum = in_cksum(m, hlen);
1000                         }
1001                 }
1002
1003                 /* Record statistics for this interface address. */
1004                 if (!(flags & IP_FORWARDING) && ia) {
1005                         ia->ia_ifa.if_opackets++;
1006                         ia->ia_ifa.if_obytes += m->m_pkthdr.len;
1007                 }
1008
1009 #ifdef IPSEC
1010                 /* clean ipsec history once it goes out of the node */
1011                 ipsec_delaux(m);
1012 #endif
1013
1014 #ifdef MBUF_STRESS_TEST
1015                 if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size) {
1016                         struct mbuf *m1, *m2;
1017                         int length, tmp;
1018
1019                         tmp = length = m->m_pkthdr.len;
1020
1021                         while ((length -= mbuf_frag_size) >= 1) {
1022                                 m1 = m_split(m, length, MB_DONTWAIT);
1023                                 if (m1 == NULL)
1024                                         break;
1025                                 m2 = m;
1026                                 while (m2->m_next != NULL)
1027                                         m2 = m2->m_next;
1028                                 m2->m_next = m1;
1029                         }
1030                         m->m_pkthdr.len = tmp;
1031                 }
1032 #endif
1033
1034 #ifdef MPLS
1035                 if (!mpls_output_process(m, ro->ro_rt))
1036                         goto done;
1037 #endif
1038                 error = ifp->if_output(ifp, m, (struct sockaddr *)dst,
1039                                        ro->ro_rt);
1040                 goto done;
1041         }
1042
1043         if (ip->ip_off & IP_DF) {
1044                 error = EMSGSIZE;
1045                 /*
1046                  * This case can happen if the user changed the MTU
1047                  * of an interface after enabling IP on it.  Because
1048                  * most netifs don't keep track of routes pointing to
1049                  * them, there is no way for one to update all its
1050                  * routes when the MTU is changed.
1051                  */
1052                 if ((ro->ro_rt->rt_flags & (RTF_UP | RTF_HOST)) &&
1053                     !(ro->ro_rt->rt_rmx.rmx_locks & RTV_MTU) &&
1054                     (ro->ro_rt->rt_rmx.rmx_mtu > ifp->if_mtu)) {
1055                         ro->ro_rt->rt_rmx.rmx_mtu = ifp->if_mtu;
1056                 }
1057                 ipstat.ips_cantfrag++;
1058                 goto bad;
1059         }
1060
1061         /*
1062          * Too large for interface; fragment if possible. If successful,
1063          * on return, m will point to a list of packets to be sent.
1064          */
1065         error = ip_fragment(ip, &m, ifp->if_mtu, ifp->if_hwassist, sw_csum);
1066         if (error)
1067                 goto bad;
1068         for (; m; m = m0) {
1069                 m0 = m->m_nextpkt;
1070                 m->m_nextpkt = NULL;
1071 #ifdef IPSEC
1072                 /* clean ipsec history once it goes out of the node */
1073                 ipsec_delaux(m);
1074 #endif
1075                 if (error == 0) {
1076                         /* Record statistics for this interface address. */
1077                         if (ia != NULL) {
1078                                 ia->ia_ifa.if_opackets++;
1079                                 ia->ia_ifa.if_obytes += m->m_pkthdr.len;
1080                         }
1081 #ifdef MPLS
1082                         if (!mpls_output_process(m, ro->ro_rt))
1083                                 continue;
1084 #endif
1085                         error = ifp->if_output(ifp, m, (struct sockaddr *)dst,
1086                                                ro->ro_rt);
1087                 } else {
1088                         m_freem(m);
1089                 }
1090         }
1091
1092         if (error == 0)
1093                 ipstat.ips_fragmented++;
1094
1095 done:
1096         if (ro == &iproute && ro->ro_rt != NULL) {
1097                 RTFREE(ro->ro_rt);
1098                 ro->ro_rt = NULL;
1099         }
1100 #ifdef IPSEC
1101         if (sp != NULL) {
1102                 KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
1103                         kprintf("DP ip_output call free SP:%p\n", sp));
1104                 key_freesp(sp);
1105         }
1106 #endif
1107 #ifdef FAST_IPSEC
1108         if (sp != NULL)
1109                 KEY_FREESP(&sp);
1110 #endif
1111         return (error);
1112 bad:
1113         m_freem(m);
1114         goto done;
1115 }
1116
1117 /*
1118  * Create a chain of fragments which fit the given mtu. m_frag points to the
1119  * mbuf to be fragmented; on return it points to the chain with the fragments.
1120  * Return 0 if no error. If error, m_frag may contain a partially built
1121  * chain of fragments that should be freed by the caller.
1122  *
1123  * if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist)
1124  * sw_csum contains the delayed checksums flags (e.g., CSUM_DELAY_IP).
1125  */
1126 int
1127 ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu,
1128             u_long if_hwassist_flags, int sw_csum)
1129 {
1130         int error = 0;
1131         int hlen = IP_VHL_HL(ip->ip_vhl) << 2;
1132         int len = (mtu - hlen) & ~7;    /* size of payload in each fragment */
1133         int off;
1134         struct mbuf *m0 = *m_frag;      /* the original packet          */
1135         int firstlen;
1136         struct mbuf **mnext;
1137         int nfrags;
1138
1139         if (ip->ip_off & IP_DF) {       /* Fragmentation not allowed */
1140                 ipstat.ips_cantfrag++;
1141                 return EMSGSIZE;
1142         }
1143
1144         /*
1145          * Must be able to put at least 8 bytes per fragment.
1146          */
1147         if (len < 8)
1148                 return EMSGSIZE;
1149
1150         /*
1151          * If the interface will not calculate checksums on
1152          * fragmented packets, then do it here.
1153          */
1154         if ((m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA) &&
1155             !(if_hwassist_flags & CSUM_IP_FRAGS)) {
1156                 in_delayed_cksum(m0);
1157                 m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
1158         }
1159
1160         if (len > PAGE_SIZE) {
1161                 /*
1162                  * Fragment large datagrams such that each segment
1163                  * contains a multiple of PAGE_SIZE amount of data,
1164                  * plus headers. This enables a receiver to perform
1165                  * page-flipping zero-copy optimizations.
1166                  *
1167                  * XXX When does this help given that sender and receiver
1168                  * could have different page sizes, and also mtu could
1169                  * be less than the receiver's page size ?
1170                  */
1171                 int newlen;
1172                 struct mbuf *m;
1173
1174                 for (m = m0, off = 0; m && (off+m->m_len) <= mtu; m = m->m_next)
1175                         off += m->m_len;
1176
1177                 /*
1178                  * firstlen (off - hlen) must be aligned on an
1179                  * 8-byte boundary
1180                  */
1181                 if (off < hlen)
1182                         goto smart_frag_failure;
1183                 off = ((off - hlen) & ~7) + hlen;
1184                 newlen = (~PAGE_MASK) & mtu;
1185                 if ((newlen + sizeof(struct ip)) > mtu) {
1186                         /* we failed, go back the default */
1187 smart_frag_failure:
1188                         newlen = len;
1189                         off = hlen + len;
1190                 }
1191                 len = newlen;
1192
1193         } else {
1194                 off = hlen + len;
1195         }
1196
1197         firstlen = off - hlen;
1198         mnext = &m0->m_nextpkt;         /* pointer to next packet */
1199
1200         /*
1201          * Loop through length of segment after first fragment,
1202          * make new header and copy data of each part and link onto chain.
1203          * Here, m0 is the original packet, m is the fragment being created.
1204          * The fragments are linked off the m_nextpkt of the original
1205          * packet, which after processing serves as the first fragment.
1206          */
1207         for (nfrags = 1; off < ip->ip_len; off += len, nfrags++) {
1208                 struct ip *mhip;        /* ip header on the fragment */
1209                 struct mbuf *m;
1210                 int mhlen = sizeof(struct ip);
1211
1212                 MGETHDR(m, MB_DONTWAIT, MT_HEADER);
1213                 if (m == NULL) {
1214                         error = ENOBUFS;
1215                         ipstat.ips_odropped++;
1216                         goto done;
1217                 }
1218                 m->m_flags |= (m0->m_flags & M_MCAST) | M_FRAG;
1219                 /*
1220                  * In the first mbuf, leave room for the link header, then
1221                  * copy the original IP header including options. The payload
1222                  * goes into an additional mbuf chain returned by m_copy().
1223                  */
1224                 m->m_data += max_linkhdr;
1225                 mhip = mtod(m, struct ip *);
1226                 *mhip = *ip;
1227                 if (hlen > sizeof(struct ip)) {
1228                         mhlen = ip_optcopy(ip, mhip) + sizeof(struct ip);
1229                         mhip->ip_vhl = IP_MAKE_VHL(IPVERSION, mhlen >> 2);
1230                 }
1231                 m->m_len = mhlen;
1232                 /* XXX do we need to add ip->ip_off below ? */
1233                 mhip->ip_off = ((off - hlen) >> 3) + ip->ip_off;
1234                 if (off + len >= ip->ip_len) {  /* last fragment */
1235                         len = ip->ip_len - off;
1236                         m->m_flags |= M_LASTFRAG;
1237                 } else
1238                         mhip->ip_off |= IP_MF;
1239                 mhip->ip_len = htons((u_short)(len + mhlen));
1240                 m->m_next = m_copy(m0, off, len);
1241                 if (m->m_next == NULL) {                /* copy failed */
1242                         m_free(m);
1243                         error = ENOBUFS;        /* ??? */
1244                         ipstat.ips_odropped++;
1245                         goto done;
1246                 }
1247                 m->m_pkthdr.len = mhlen + len;
1248                 m->m_pkthdr.rcvif = (struct ifnet *)NULL;
1249                 m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags;
1250                 mhip->ip_off = htons(mhip->ip_off);
1251                 mhip->ip_sum = 0;
1252                 if (sw_csum & CSUM_DELAY_IP)
1253                         mhip->ip_sum = in_cksum(m, mhlen);
1254                 *mnext = m;
1255                 mnext = &m->m_nextpkt;
1256         }
1257         ipstat.ips_ofragments += nfrags;
1258
1259         /* set first marker for fragment chain */
1260         m0->m_flags |= M_FIRSTFRAG | M_FRAG;
1261         m0->m_pkthdr.csum_data = nfrags;
1262
1263         /*
1264          * Update first fragment by trimming what's been copied out
1265          * and updating header.
1266          */
1267         m_adj(m0, hlen + firstlen - ip->ip_len);
1268         m0->m_pkthdr.len = hlen + firstlen;
1269         ip->ip_len = htons((u_short)m0->m_pkthdr.len);
1270         ip->ip_off |= IP_MF;
1271         ip->ip_off = htons(ip->ip_off);
1272         ip->ip_sum = 0;
1273         if (sw_csum & CSUM_DELAY_IP)
1274                 ip->ip_sum = in_cksum(m0, hlen);
1275
1276 done:
1277         *m_frag = m0;
1278         return error;
1279 }
1280
1281 void
1282 in_delayed_cksum(struct mbuf *m)
1283 {
1284         struct ip *ip;
1285         u_short csum, offset;
1286
1287         ip = mtod(m, struct ip *);
1288         offset = IP_VHL_HL(ip->ip_vhl) << 2 ;
1289         csum = in_cksum_skip(m, ip->ip_len, offset);
1290         if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0)
1291                 csum = 0xffff;
1292         offset += m->m_pkthdr.csum_data;        /* checksum offset */
1293
1294         if (offset + sizeof(u_short) > m->m_len) {
1295                 kprintf("delayed m_pullup, m->len: %d  off: %d  p: %d\n",
1296                     m->m_len, offset, ip->ip_p);
1297                 /*
1298                  * XXX
1299                  * this shouldn't happen, but if it does, the
1300                  * correct behavior may be to insert the checksum
1301                  * in the existing chain instead of rearranging it.
1302                  */
1303                 m = m_pullup(m, offset + sizeof(u_short));
1304         }
1305         *(u_short *)(m->m_data + offset) = csum;
1306 }
1307
1308 /*
1309  * Insert IP options into preformed packet.
1310  * Adjust IP destination as required for IP source routing,
1311  * as indicated by a non-zero in_addr at the start of the options.
1312  *
1313  * XXX This routine assumes that the packet has no options in place.
1314  */
1315 static struct mbuf *
1316 ip_insertoptions(struct mbuf *m, struct mbuf *opt, int *phlen)
1317 {
1318         struct ipoption *p = mtod(opt, struct ipoption *);
1319         struct mbuf *n;
1320         struct ip *ip = mtod(m, struct ip *);
1321         unsigned optlen;
1322
1323         optlen = opt->m_len - sizeof p->ipopt_dst;
1324         if (optlen + (u_short)ip->ip_len > IP_MAXPACKET) {
1325                 *phlen = 0;
1326                 return (m);             /* XXX should fail */
1327         }
1328         if (p->ipopt_dst.s_addr)
1329                 ip->ip_dst = p->ipopt_dst;
1330         if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) {
1331                 MGETHDR(n, MB_DONTWAIT, MT_HEADER);
1332                 if (n == NULL) {
1333                         *phlen = 0;
1334                         return (m);
1335                 }
1336                 n->m_pkthdr.rcvif = (struct ifnet *)NULL;
1337                 n->m_pkthdr.len = m->m_pkthdr.len + optlen;
1338                 m->m_len -= sizeof(struct ip);
1339                 m->m_data += sizeof(struct ip);
1340                 n->m_next = m;
1341                 m = n;
1342                 m->m_len = optlen + sizeof(struct ip);
1343                 m->m_data += max_linkhdr;
1344                 memcpy(mtod(m, void *), ip, sizeof(struct ip));
1345         } else {
1346                 m->m_data -= optlen;
1347                 m->m_len += optlen;
1348                 m->m_pkthdr.len += optlen;
1349                 ovbcopy(ip, mtod(m, caddr_t), sizeof(struct ip));
1350         }
1351         ip = mtod(m, struct ip *);
1352         bcopy(p->ipopt_list, ip + 1, optlen);
1353         *phlen = sizeof(struct ip) + optlen;
1354         ip->ip_vhl = IP_MAKE_VHL(IPVERSION, *phlen >> 2);
1355         ip->ip_len += optlen;
1356         return (m);
1357 }
1358
1359 /*
1360  * Copy options from ip to jp,
1361  * omitting those not copied during fragmentation.
1362  */
1363 int
1364 ip_optcopy(struct ip *ip, struct ip *jp)
1365 {
1366         u_char *cp, *dp;
1367         int opt, optlen, cnt;
1368
1369         cp = (u_char *)(ip + 1);
1370         dp = (u_char *)(jp + 1);
1371         cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip);
1372         for (; cnt > 0; cnt -= optlen, cp += optlen) {
1373                 opt = cp[0];
1374                 if (opt == IPOPT_EOL)
1375                         break;
1376                 if (opt == IPOPT_NOP) {
1377                         /* Preserve for IP mcast tunnel's LSRR alignment. */
1378                         *dp++ = IPOPT_NOP;
1379                         optlen = 1;
1380                         continue;
1381                 }
1382
1383                 KASSERT(cnt >= IPOPT_OLEN + sizeof *cp,
1384                     ("ip_optcopy: malformed ipv4 option"));
1385                 optlen = cp[IPOPT_OLEN];
1386                 KASSERT(optlen >= IPOPT_OLEN + sizeof *cp && optlen <= cnt,
1387                     ("ip_optcopy: malformed ipv4 option"));
1388
1389                 /* bogus lengths should have been caught by ip_dooptions */
1390                 if (optlen > cnt)
1391                         optlen = cnt;
1392                 if (IPOPT_COPIED(opt)) {
1393                         bcopy(cp, dp, optlen);
1394                         dp += optlen;
1395                 }
1396         }
1397         for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++)
1398                 *dp++ = IPOPT_EOL;
1399         return (optlen);
1400 }
1401
1402 /*
1403  * IP socket option processing.
1404  */
1405 int
1406 ip_ctloutput(struct socket *so, struct sockopt *sopt)
1407 {
1408         struct  inpcb *inp = so->so_pcb;
1409         int     error, optval;
1410
1411         error = optval = 0;
1412         if (sopt->sopt_level != IPPROTO_IP) {
1413                 return (EINVAL);
1414         }
1415
1416         switch (sopt->sopt_dir) {
1417         case SOPT_SET:
1418                 switch (sopt->sopt_name) {
1419                 case IP_OPTIONS:
1420 #ifdef notyet
1421                 case IP_RETOPTS:
1422 #endif
1423                 {
1424                         struct mbuf *m;
1425                         if (sopt->sopt_valsize > MLEN) {
1426                                 error = EMSGSIZE;
1427                                 break;
1428                         }
1429                         MGET(m, sopt->sopt_td ? MB_WAIT : MB_DONTWAIT, MT_HEADER);
1430                         if (m == NULL) {
1431                                 error = ENOBUFS;
1432                                 break;
1433                         }
1434                         m->m_len = sopt->sopt_valsize;
1435                         error = soopt_to_kbuf(sopt, mtod(m, void *), m->m_len,
1436                                               m->m_len);
1437                         return (ip_pcbopts(sopt->sopt_name, &inp->inp_options,
1438                                            m));
1439                 }
1440
1441                 case IP_TOS:
1442                 case IP_TTL:
1443                 case IP_MINTTL:
1444                 case IP_RECVOPTS:
1445                 case IP_RECVRETOPTS:
1446                 case IP_RECVDSTADDR:
1447                 case IP_RECVIF:
1448                 case IP_RECVTTL:
1449                 case IP_FAITH:
1450                         error = soopt_to_kbuf(sopt, &optval, sizeof optval,
1451                                              sizeof optval);
1452                         if (error)
1453                                 break;
1454                         switch (sopt->sopt_name) {
1455                         case IP_TOS:
1456                                 inp->inp_ip_tos = optval;
1457                                 break;
1458
1459                         case IP_TTL:
1460                                 inp->inp_ip_ttl = optval;
1461                                 break;
1462                         case IP_MINTTL:
1463                                 if (optval > 0 && optval <= MAXTTL)
1464                                         inp->inp_ip_minttl = optval;
1465                                 else
1466                                         error = EINVAL;
1467                                 break;
1468 #define OPTSET(bit) \
1469         if (optval) \
1470                 inp->inp_flags |= bit; \
1471         else \
1472                 inp->inp_flags &= ~bit;
1473
1474                         case IP_RECVOPTS:
1475                                 OPTSET(INP_RECVOPTS);
1476                                 break;
1477
1478                         case IP_RECVRETOPTS:
1479                                 OPTSET(INP_RECVRETOPTS);
1480                                 break;
1481
1482                         case IP_RECVDSTADDR:
1483                                 OPTSET(INP_RECVDSTADDR);
1484                                 break;
1485
1486                         case IP_RECVIF:
1487                                 OPTSET(INP_RECVIF);
1488                                 break;
1489
1490                         case IP_RECVTTL:
1491                                 OPTSET(INP_RECVTTL);
1492                                 break;
1493
1494                         case IP_FAITH:
1495                                 OPTSET(INP_FAITH);
1496                                 break;
1497                         }
1498                         break;
1499 #undef OPTSET
1500
1501                 case IP_MULTICAST_IF:
1502                 case IP_MULTICAST_VIF:
1503                 case IP_MULTICAST_TTL:
1504                 case IP_MULTICAST_LOOP:
1505                 case IP_ADD_MEMBERSHIP:
1506                 case IP_DROP_MEMBERSHIP:
1507                         error = ip_setmoptions(sopt, &inp->inp_moptions);
1508                         break;
1509
1510                 case IP_PORTRANGE:
1511                         error = soopt_to_kbuf(sopt, &optval, sizeof optval,
1512                                             sizeof optval);
1513                         if (error)
1514                                 break;
1515
1516                         switch (optval) {
1517                         case IP_PORTRANGE_DEFAULT:
1518                                 inp->inp_flags &= ~(INP_LOWPORT);
1519                                 inp->inp_flags &= ~(INP_HIGHPORT);
1520                                 break;
1521
1522                         case IP_PORTRANGE_HIGH:
1523                                 inp->inp_flags &= ~(INP_LOWPORT);
1524                                 inp->inp_flags |= INP_HIGHPORT;
1525                                 break;
1526
1527                         case IP_PORTRANGE_LOW:
1528                                 inp->inp_flags &= ~(INP_HIGHPORT);
1529                                 inp->inp_flags |= INP_LOWPORT;
1530                                 break;
1531
1532                         default:
1533                                 error = EINVAL;
1534                                 break;
1535                         }
1536                         break;
1537
1538 #if defined(IPSEC) || defined(FAST_IPSEC)
1539                 case IP_IPSEC_POLICY:
1540                 {
1541                         caddr_t req;
1542                         size_t len = 0;
1543                         int priv;
1544                         struct mbuf *m;
1545                         int optname;
1546
1547                         if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */
1548                                 break;
1549                         soopt_to_mbuf(sopt, m);
1550                         priv = (sopt->sopt_td != NULL &&
1551                                 suser(sopt->sopt_td) != 0) ? 0 : 1;
1552                         req = mtod(m, caddr_t);
1553                         len = m->m_len;
1554                         optname = sopt->sopt_name;
1555                         error = ipsec4_set_policy(inp, optname, req, len, priv);
1556                         m_freem(m);
1557                         break;
1558                 }
1559 #endif /*IPSEC*/
1560
1561                 default:
1562                         error = ENOPROTOOPT;
1563                         break;
1564                 }
1565                 break;
1566
1567         case SOPT_GET:
1568                 switch (sopt->sopt_name) {
1569                 case IP_OPTIONS:
1570                 case IP_RETOPTS:
1571                         if (inp->inp_options)
1572                                 soopt_from_kbuf(sopt, mtod(inp->inp_options,
1573                                                            char *),
1574                                                 inp->inp_options->m_len);
1575                         else
1576                                 sopt->sopt_valsize = 0;
1577                         break;
1578
1579                 case IP_TOS:
1580                 case IP_TTL:
1581                 case IP_MINTTL:
1582                 case IP_RECVOPTS:
1583                 case IP_RECVRETOPTS:
1584                 case IP_RECVDSTADDR:
1585                 case IP_RECVTTL:
1586                 case IP_RECVIF:
1587                 case IP_PORTRANGE:
1588                 case IP_FAITH:
1589                         switch (sopt->sopt_name) {
1590
1591                         case IP_TOS:
1592                                 optval = inp->inp_ip_tos;
1593                                 break;
1594
1595                         case IP_TTL:
1596                                 optval = inp->inp_ip_ttl;
1597                                 break;
1598                         case IP_MINTTL:
1599                                 optval = inp->inp_ip_minttl;
1600                                 break;
1601
1602 #define OPTBIT(bit)     (inp->inp_flags & bit ? 1 : 0)
1603
1604                         case IP_RECVOPTS:
1605                                 optval = OPTBIT(INP_RECVOPTS);
1606                                 break;
1607
1608                         case IP_RECVRETOPTS:
1609                                 optval = OPTBIT(INP_RECVRETOPTS);
1610                                 break;
1611
1612                         case IP_RECVDSTADDR:
1613                                 optval = OPTBIT(INP_RECVDSTADDR);
1614                                 break;
1615
1616                         case IP_RECVTTL:
1617                                 optval = OPTBIT(INP_RECVTTL);
1618                                 break;
1619
1620                         case IP_RECVIF:
1621                                 optval = OPTBIT(INP_RECVIF);
1622                                 break;
1623
1624                         case IP_PORTRANGE:
1625                                 if (inp->inp_flags & INP_HIGHPORT)
1626                                         optval = IP_PORTRANGE_HIGH;
1627                                 else if (inp->inp_flags & INP_LOWPORT)
1628                                         optval = IP_PORTRANGE_LOW;
1629                                 else
1630                                         optval = 0;
1631                                 break;
1632
1633                         case IP_FAITH:
1634                                 optval = OPTBIT(INP_FAITH);
1635                                 break;
1636                         }
1637                         soopt_from_kbuf(sopt, &optval, sizeof optval);
1638                         break;
1639
1640                 case IP_MULTICAST_IF:
1641                 case IP_MULTICAST_VIF:
1642                 case IP_MULTICAST_TTL:
1643                 case IP_MULTICAST_LOOP:
1644                 case IP_ADD_MEMBERSHIP:
1645                 case IP_DROP_MEMBERSHIP:
1646                         error = ip_getmoptions(sopt, inp->inp_moptions);
1647                         break;
1648
1649 #if defined(IPSEC) || defined(FAST_IPSEC)
1650                 case IP_IPSEC_POLICY:
1651                 {
1652                         struct mbuf *m = NULL;
1653                         caddr_t req = NULL;
1654                         size_t len = 0;
1655
1656                         if (m != NULL) {
1657                                 req = mtod(m, caddr_t);
1658                                 len = m->m_len;
1659                         }
1660                         error = ipsec4_get_policy(so->so_pcb, req, len, &m);
1661                         if (error == 0)
1662                                 error = soopt_from_mbuf(sopt, m); /* XXX */
1663                         if (error == 0)
1664                                 m_freem(m);
1665                         break;
1666                 }
1667 #endif /*IPSEC*/
1668
1669                 default:
1670                         error = ENOPROTOOPT;
1671                         break;
1672                 }
1673                 break;
1674         }
1675         return (error);
1676 }
1677
1678 /*
1679  * Set up IP options in pcb for insertion in output packets.
1680  * Store in mbuf with pointer in pcbopt, adding pseudo-option
1681  * with destination address if source routed.
1682  */
1683 static int
1684 ip_pcbopts(int optname, struct mbuf **pcbopt, struct mbuf *m)
1685 {
1686         int cnt, optlen;
1687         u_char *cp;
1688         u_char opt;
1689
1690         /* turn off any old options */
1691         if (*pcbopt)
1692                 m_free(*pcbopt);
1693         *pcbopt = 0;
1694         if (m == NULL || m->m_len == 0) {
1695                 /*
1696                  * Only turning off any previous options.
1697                  */
1698                 if (m != NULL)
1699                         m_free(m);
1700                 return (0);
1701         }
1702
1703         if (m->m_len % sizeof(int32_t))
1704                 goto bad;
1705         /*
1706          * IP first-hop destination address will be stored before
1707          * actual options; move other options back
1708          * and clear it when none present.
1709          */
1710         if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN])
1711                 goto bad;
1712         cnt = m->m_len;
1713         m->m_len += sizeof(struct in_addr);
1714         cp = mtod(m, u_char *) + sizeof(struct in_addr);
1715         ovbcopy(mtod(m, caddr_t), cp, cnt);
1716         bzero(mtod(m, caddr_t), sizeof(struct in_addr));
1717
1718         for (; cnt > 0; cnt -= optlen, cp += optlen) {
1719                 opt = cp[IPOPT_OPTVAL];
1720                 if (opt == IPOPT_EOL)
1721                         break;
1722                 if (opt == IPOPT_NOP)
1723                         optlen = 1;
1724                 else {
1725                         if (cnt < IPOPT_OLEN + sizeof *cp)
1726                                 goto bad;
1727                         optlen = cp[IPOPT_OLEN];
1728                         if (optlen < IPOPT_OLEN + sizeof *cp || optlen > cnt)
1729                                 goto bad;
1730                 }
1731                 switch (opt) {
1732
1733                 default:
1734                         break;
1735
1736                 case IPOPT_LSRR:
1737                 case IPOPT_SSRR:
1738                         /*
1739                          * user process specifies route as:
1740                          *      ->A->B->C->D
1741                          * D must be our final destination (but we can't
1742                          * check that since we may not have connected yet).
1743                          * A is first hop destination, which doesn't appear in
1744                          * actual IP option, but is stored before the options.
1745                          */
1746                         if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr))
1747                                 goto bad;
1748                         m->m_len -= sizeof(struct in_addr);
1749                         cnt -= sizeof(struct in_addr);
1750                         optlen -= sizeof(struct in_addr);
1751                         cp[IPOPT_OLEN] = optlen;
1752                         /*
1753                          * Move first hop before start of options.
1754                          */
1755                         bcopy(&cp[IPOPT_OFFSET+1], mtod(m, caddr_t),
1756                               sizeof(struct in_addr));
1757                         /*
1758                          * Then copy rest of options back
1759                          * to close up the deleted entry.
1760                          */
1761                         ovbcopy(&cp[IPOPT_OFFSET+1] + sizeof(struct in_addr),
1762                                 &cp[IPOPT_OFFSET+1],
1763                                 cnt - (IPOPT_MINOFF - 1));
1764                         break;
1765                 }
1766         }
1767         if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr))
1768                 goto bad;
1769         *pcbopt = m;
1770         return (0);
1771
1772 bad:
1773         m_free(m);
1774         return (EINVAL);
1775 }
1776
1777 /*
1778  * XXX
1779  * The whole multicast option thing needs to be re-thought.
1780  * Several of these options are equally applicable to non-multicast
1781  * transmission, and one (IP_MULTICAST_TTL) totally duplicates a
1782  * standard option (IP_TTL).
1783  */
1784
1785 /*
1786  * following RFC1724 section 3.3, 0.0.0.0/8 is interpreted as interface index.
1787  */
1788 static struct ifnet *
1789 ip_multicast_if(struct in_addr *a, int *ifindexp)
1790 {
1791         int ifindex;
1792         struct ifnet *ifp;
1793
1794         if (ifindexp)
1795                 *ifindexp = 0;
1796         if (ntohl(a->s_addr) >> 24 == 0) {
1797                 ifindex = ntohl(a->s_addr) & 0xffffff;
1798                 if (ifindex < 0 || if_index < ifindex)
1799                         return NULL;
1800                 ifp = ifindex2ifnet[ifindex];
1801                 if (ifindexp)
1802                         *ifindexp = ifindex;
1803         } else {
1804                 ifp = INADDR_TO_IFP(a);
1805         }
1806         return ifp;
1807 }
1808
1809 /*
1810  * Set the IP multicast options in response to user setsockopt().
1811  */
1812 static int
1813 ip_setmoptions(struct sockopt *sopt, struct ip_moptions **imop)
1814 {
1815         int error = 0;
1816         int i;
1817         struct in_addr addr;
1818         struct ip_mreq mreq;
1819         struct ifnet *ifp;
1820         struct ip_moptions *imo = *imop;
1821         int ifindex;
1822
1823         if (imo == NULL) {
1824                 /*
1825                  * No multicast option buffer attached to the pcb;
1826                  * allocate one and initialize to default values.
1827                  */
1828                 imo = kmalloc(sizeof *imo, M_IPMOPTS, M_WAITOK);
1829
1830                 *imop = imo;
1831                 imo->imo_multicast_ifp = NULL;
1832                 imo->imo_multicast_addr.s_addr = INADDR_ANY;
1833                 imo->imo_multicast_vif = -1;
1834                 imo->imo_multicast_ttl = IP_DEFAULT_MULTICAST_TTL;
1835                 imo->imo_multicast_loop = IP_DEFAULT_MULTICAST_LOOP;
1836                 imo->imo_num_memberships = 0;
1837         }
1838         switch (sopt->sopt_name) {
1839         /* store an index number for the vif you wanna use in the send */
1840         case IP_MULTICAST_VIF:
1841                 if (legal_vif_num == 0) {
1842                         error = EOPNOTSUPP;
1843                         break;
1844                 }
1845                 error = soopt_to_kbuf(sopt, &i, sizeof i, sizeof i);
1846                 if (error)
1847                         break;
1848                 if (!legal_vif_num(i) && (i != -1)) {
1849                         error = EINVAL;
1850                         break;
1851                 }
1852                 imo->imo_multicast_vif = i;
1853                 break;
1854
1855         case IP_MULTICAST_IF:
1856                 /*
1857                  * Select the interface for outgoing multicast packets.
1858                  */
1859                 error = soopt_to_kbuf(sopt, &addr, sizeof addr, sizeof addr);
1860                 if (error)
1861                         break;
1862
1863                 /*
1864                  * INADDR_ANY is used to remove a previous selection.
1865                  * When no interface is selected, a default one is
1866                  * chosen every time a multicast packet is sent.
1867                  */
1868                 if (addr.s_addr == INADDR_ANY) {
1869                         imo->imo_multicast_ifp = NULL;
1870                         break;
1871                 }
1872                 /*
1873                  * The selected interface is identified by its local
1874                  * IP address.  Find the interface and confirm that
1875                  * it supports multicasting.
1876                  */
1877                 crit_enter();
1878                 ifp = ip_multicast_if(&addr, &ifindex);
1879                 if (ifp == NULL || !(ifp->if_flags & IFF_MULTICAST)) {
1880                         crit_exit();
1881                         error = EADDRNOTAVAIL;
1882                         break;
1883                 }
1884                 imo->imo_multicast_ifp = ifp;
1885                 if (ifindex)
1886                         imo->imo_multicast_addr = addr;
1887                 else
1888                         imo->imo_multicast_addr.s_addr = INADDR_ANY;
1889                 crit_exit();
1890                 break;
1891
1892         case IP_MULTICAST_TTL:
1893                 /*
1894                  * Set the IP time-to-live for outgoing multicast packets.
1895                  * The original multicast API required a char argument,
1896                  * which is inconsistent with the rest of the socket API.
1897                  * We allow either a char or an int.
1898                  */
1899                 if (sopt->sopt_valsize == 1) {
1900                         u_char ttl;
1901                         error = soopt_to_kbuf(sopt, &ttl, 1, 1);
1902                         if (error)
1903                                 break;
1904                         imo->imo_multicast_ttl = ttl;
1905                 } else {
1906                         u_int ttl;
1907                         error = soopt_to_kbuf(sopt, &ttl, sizeof ttl, sizeof ttl);
1908                         if (error)
1909                                 break;
1910                         if (ttl > 255)
1911                                 error = EINVAL;
1912                         else
1913                                 imo->imo_multicast_ttl = ttl;
1914                 }
1915                 break;
1916
1917         case IP_MULTICAST_LOOP:
1918                 /*
1919                  * Set the loopback flag for outgoing multicast packets.
1920                  * Must be zero or one.  The original multicast API required a
1921                  * char argument, which is inconsistent with the rest
1922                  * of the socket API.  We allow either a char or an int.
1923                  */
1924                 if (sopt->sopt_valsize == 1) {
1925                         u_char loop;
1926
1927                         error = soopt_to_kbuf(sopt, &loop, 1, 1);
1928                         if (error)
1929                                 break;
1930                         imo->imo_multicast_loop = !!loop;
1931                 } else {
1932                         u_int loop;
1933
1934                         error = soopt_to_kbuf(sopt, &loop, sizeof loop,
1935                                             sizeof loop);
1936                         if (error)
1937                                 break;
1938                         imo->imo_multicast_loop = !!loop;
1939                 }
1940                 break;
1941
1942         case IP_ADD_MEMBERSHIP:
1943                 /*
1944                  * Add a multicast group membership.
1945                  * Group must be a valid IP multicast address.
1946                  */
1947                 error = soopt_to_kbuf(sopt, &mreq, sizeof mreq, sizeof mreq);
1948                 if (error)
1949                         break;
1950
1951                 if (!IN_MULTICAST(ntohl(mreq.imr_multiaddr.s_addr))) {
1952                         error = EINVAL;
1953                         break;
1954                 }
1955                 crit_enter();
1956                 /*
1957                  * If no interface address was provided, use the interface of
1958                  * the route to the given multicast address.
1959                  */
1960                 if (mreq.imr_interface.s_addr == INADDR_ANY) {
1961                         struct sockaddr_in dst;
1962                         struct rtentry *rt;
1963
1964                         bzero(&dst, sizeof(struct sockaddr_in));
1965                         dst.sin_len = sizeof(struct sockaddr_in);
1966                         dst.sin_family = AF_INET;
1967                         dst.sin_addr = mreq.imr_multiaddr;
1968                         rt = rtlookup((struct sockaddr *)&dst);
1969                         if (rt == NULL) {
1970                                 error = EADDRNOTAVAIL;
1971                                 crit_exit();
1972                                 break;
1973                         }
1974                         --rt->rt_refcnt;
1975                         ifp = rt->rt_ifp;
1976                 } else {
1977                         ifp = ip_multicast_if(&mreq.imr_interface, NULL);
1978                 }
1979
1980                 /*
1981                  * See if we found an interface, and confirm that it
1982                  * supports multicast.
1983                  */
1984                 if (ifp == NULL || !(ifp->if_flags & IFF_MULTICAST)) {
1985                         error = EADDRNOTAVAIL;
1986                         crit_exit();
1987                         break;
1988                 }
1989                 /*
1990                  * See if the membership already exists or if all the
1991                  * membership slots are full.
1992                  */
1993                 for (i = 0; i < imo->imo_num_memberships; ++i) {
1994                         if (imo->imo_membership[i]->inm_ifp == ifp &&
1995                             imo->imo_membership[i]->inm_addr.s_addr
1996                                                 == mreq.imr_multiaddr.s_addr)
1997                                 break;
1998                 }
1999                 if (i < imo->imo_num_memberships) {
2000                         error = EADDRINUSE;
2001                         crit_exit();
2002                         break;
2003                 }
2004                 if (i == IP_MAX_MEMBERSHIPS) {
2005                         error = ETOOMANYREFS;
2006                         crit_exit();
2007                         break;
2008                 }
2009                 /*
2010                  * Everything looks good; add a new record to the multicast
2011                  * address list for the given interface.
2012                  */
2013                 if ((imo->imo_membership[i] =
2014                      in_addmulti(&mreq.imr_multiaddr, ifp)) == NULL) {
2015                         error = ENOBUFS;
2016                         crit_exit();
2017                         break;
2018                 }
2019                 ++imo->imo_num_memberships;
2020                 crit_exit();
2021                 break;
2022
2023         case IP_DROP_MEMBERSHIP:
2024                 /*
2025                  * Drop a multicast group membership.
2026                  * Group must be a valid IP multicast address.
2027                  */
2028                 error = soopt_to_kbuf(sopt, &mreq, sizeof mreq, sizeof mreq);
2029                 if (error)
2030                         break;
2031
2032                 if (!IN_MULTICAST(ntohl(mreq.imr_multiaddr.s_addr))) {
2033                         error = EINVAL;
2034                         break;
2035                 }
2036
2037                 crit_enter();
2038                 /*
2039                  * If an interface address was specified, get a pointer
2040                  * to its ifnet structure.
2041                  */
2042                 if (mreq.imr_interface.s_addr == INADDR_ANY)
2043                         ifp = NULL;
2044                 else {
2045                         ifp = ip_multicast_if(&mreq.imr_interface, NULL);
2046                         if (ifp == NULL) {
2047                                 error = EADDRNOTAVAIL;
2048                                 crit_exit();
2049                                 break;
2050                         }
2051                 }
2052                 /*
2053                  * Find the membership in the membership array.
2054                  */
2055                 for (i = 0; i < imo->imo_num_memberships; ++i) {
2056                         if ((ifp == NULL ||
2057                              imo->imo_membership[i]->inm_ifp == ifp) &&
2058                             imo->imo_membership[i]->inm_addr.s_addr ==
2059                             mreq.imr_multiaddr.s_addr)
2060                                 break;
2061                 }
2062                 if (i == imo->imo_num_memberships) {
2063                         error = EADDRNOTAVAIL;
2064                         crit_exit();
2065                         break;
2066                 }
2067                 /*
2068                  * Give up the multicast address record to which the
2069                  * membership points.
2070                  */
2071                 in_delmulti(imo->imo_membership[i]);
2072                 /*
2073                  * Remove the gap in the membership array.
2074                  */
2075                 for (++i; i < imo->imo_num_memberships; ++i)
2076                         imo->imo_membership[i-1] = imo->imo_membership[i];
2077                 --imo->imo_num_memberships;
2078                 crit_exit();
2079                 break;
2080
2081         default:
2082                 error = EOPNOTSUPP;
2083                 break;
2084         }
2085
2086         /*
2087          * If all options have default values, no need to keep the mbuf.
2088          */
2089         if (imo->imo_multicast_ifp == NULL &&
2090             imo->imo_multicast_vif == -1 &&
2091             imo->imo_multicast_ttl == IP_DEFAULT_MULTICAST_TTL &&
2092             imo->imo_multicast_loop == IP_DEFAULT_MULTICAST_LOOP &&
2093             imo->imo_num_memberships == 0) {
2094                 kfree(*imop, M_IPMOPTS);
2095                 *imop = NULL;
2096         }
2097
2098         return (error);
2099 }
2100
2101 /*
2102  * Return the IP multicast options in response to user getsockopt().
2103  */
2104 static int
2105 ip_getmoptions(struct sockopt *sopt, struct ip_moptions *imo)
2106 {
2107         struct in_addr addr;
2108         struct in_ifaddr *ia;
2109         int error, optval;
2110         u_char coptval;
2111
2112         error = 0;
2113         switch (sopt->sopt_name) {
2114         case IP_MULTICAST_VIF:
2115                 if (imo != NULL)
2116                         optval = imo->imo_multicast_vif;
2117                 else
2118                         optval = -1;
2119                 soopt_from_kbuf(sopt, &optval, sizeof optval);
2120                 break;
2121
2122         case IP_MULTICAST_IF:
2123                 if (imo == NULL || imo->imo_multicast_ifp == NULL)
2124                         addr.s_addr = INADDR_ANY;
2125                 else if (imo->imo_multicast_addr.s_addr) {
2126                         /* return the value user has set */
2127                         addr = imo->imo_multicast_addr;
2128                 } else {
2129                         ia = IFP_TO_IA(imo->imo_multicast_ifp);
2130                         addr.s_addr = (ia == NULL) ? INADDR_ANY
2131                                 : IA_SIN(ia)->sin_addr.s_addr;
2132                 }
2133                 soopt_from_kbuf(sopt, &addr, sizeof addr);
2134                 break;
2135
2136         case IP_MULTICAST_TTL:
2137                 if (imo == NULL)
2138                         optval = coptval = IP_DEFAULT_MULTICAST_TTL;
2139                 else
2140                         optval = coptval = imo->imo_multicast_ttl;
2141                 if (sopt->sopt_valsize == 1)
2142                         soopt_from_kbuf(sopt, &coptval, 1);
2143                 else
2144                         soopt_from_kbuf(sopt, &optval, sizeof optval);
2145                 break;
2146
2147         case IP_MULTICAST_LOOP:
2148                 if (imo == NULL)
2149                         optval = coptval = IP_DEFAULT_MULTICAST_LOOP;
2150                 else
2151                         optval = coptval = imo->imo_multicast_loop;
2152                 if (sopt->sopt_valsize == 1)
2153                         soopt_from_kbuf(sopt, &coptval, 1);
2154                 else
2155                         soopt_from_kbuf(sopt, &optval, sizeof optval);
2156                 break;
2157
2158         default:
2159                 error = ENOPROTOOPT;
2160                 break;
2161         }
2162         return (error);
2163 }
2164
2165 /*
2166  * Discard the IP multicast options.
2167  */
2168 void
2169 ip_freemoptions(struct ip_moptions *imo)
2170 {
2171         int i;
2172
2173         if (imo != NULL) {
2174                 for (i = 0; i < imo->imo_num_memberships; ++i)
2175                         in_delmulti(imo->imo_membership[i]);
2176                 kfree(imo, M_IPMOPTS);
2177         }
2178 }
2179
2180 /*
2181  * Routine called from ip_output() to loop back a copy of an IP multicast
2182  * packet to the input queue of a specified interface.  Note that this
2183  * calls the output routine of the loopback "driver", but with an interface
2184  * pointer that might NOT be a loopback interface -- evil, but easier than
2185  * replicating that code here.
2186  */
2187 static void
2188 ip_mloopback(struct ifnet *ifp, struct mbuf *m, struct sockaddr_in *dst,
2189              int hlen)
2190 {
2191         struct ip *ip;
2192         struct mbuf *copym;
2193
2194         copym = m_copypacket(m, MB_DONTWAIT);
2195         if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen))
2196                 copym = m_pullup(copym, hlen);
2197         if (copym != NULL) {
2198                 /*
2199                  * if the checksum hasn't been computed, mark it as valid
2200                  */
2201                 if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
2202                         in_delayed_cksum(copym);
2203                         copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
2204                         copym->m_pkthdr.csum_flags |=
2205                             CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
2206                         copym->m_pkthdr.csum_data = 0xffff;
2207                 }
2208                 /*
2209                  * We don't bother to fragment if the IP length is greater
2210                  * than the interface's MTU.  Can this possibly matter?
2211                  */
2212                 ip = mtod(copym, struct ip *);
2213                 ip->ip_len = htons(ip->ip_len);
2214                 ip->ip_off = htons(ip->ip_off);
2215                 ip->ip_sum = 0;
2216                 if (ip->ip_vhl == IP_VHL_BORING) {
2217                         ip->ip_sum = in_cksum_hdr(ip);
2218                 } else {
2219                         ip->ip_sum = in_cksum(copym, hlen);
2220                 }
2221                 /*
2222                  * NB:
2223                  * It's not clear whether there are any lingering
2224                  * reentrancy problems in other areas which might
2225                  * be exposed by using ip_input directly (in
2226                  * particular, everything which modifies the packet
2227                  * in-place).  Yet another option is using the
2228                  * protosw directly to deliver the looped back
2229                  * packet.  For the moment, we'll err on the side
2230                  * of safety by using if_simloop().
2231                  */
2232 #if 1 /* XXX */
2233                 if (dst->sin_family != AF_INET) {
2234                         kprintf("ip_mloopback: bad address family %d\n",
2235                                                 dst->sin_family);
2236                         dst->sin_family = AF_INET;
2237                 }
2238 #endif
2239
2240 #ifdef notdef
2241                 copym->m_pkthdr.rcvif = ifp;
2242                 ip_input(copym);
2243 #else
2244                 if_simloop(ifp, copym, dst->sin_family, 0);
2245 #endif
2246         }
2247 }