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  */
  32
  33 #define _IP_VHL
  34
  35 #include "opt_ipdn.h"
  36 #include "opt_ipdivert.h"
  37 #include "opt_ipsec.h"
  38 #include "opt_mbuf_stress_test.h"
  39 #include "opt_mpls.h"
  40
  41 #include <sys/param.h>
  42 #include <sys/systm.h>
  43 #include <sys/kernel.h>
  44 #include <sys/malloc.h>
  45 #include <sys/mbuf.h>
  46 #include <sys/protosw.h>
  47 #include <sys/socket.h>
  48 #include <sys/socketvar.h>
  49 #include <sys/proc.h>
  50 #include <sys/priv.h>
  51 #include <sys/sysctl.h>
  52 #include <sys/in_cksum.h>
  53 #include <sys/lock.h>
  54
  55 #include <sys/thread2.h>
  56 #include <sys/mplock2.h>
  57 #include <sys/msgport2.h>
  58
  59 #include <net/if.h>
  60 #include <net/netisr.h>
  61 #include <net/pfil.h>
  62 #include <net/route.h>
  63
  64 #include <netinet/in.h>
  65 #include <netinet/in_systm.h>
  66 #include <netinet/ip.h>
  67 #include <netinet/in_pcb.h>
  68 #include <netinet/in_var.h>
  69 #include <netinet/ip_var.h>
  70
  71 #include <netproto/mpls/mpls_var.h>
  72
  73 static MALLOC_DEFINE(M_IPMOPTS, "ip_moptions", "internet multicast options");
  74
  75 #ifdef IPSEC
  76 #include <netinet6/ipsec.h>
  77 #include <netproto/key/key.h>
  78 #ifdef IPSEC_DEBUG
  79 #include <netproto/key/key_debug.h>
  80 #else
  81 #define KEYDEBUG(lev,arg)
  82 #endif
  83 #endif /*IPSEC*/
  84
  85 #ifdef FAST_IPSEC
  86 #include <netproto/ipsec/ipsec.h>
  87 #include <netproto/ipsec/xform.h>
  88 #include <netproto/ipsec/key.h>
  89 #endif /*FAST_IPSEC*/
  90
  91 #include <net/ipfw/ip_fw.h>
  92 #include <net/dummynet/ip_dummynet.h>
  93
  94 #define print_ip(x, a, y)        kprintf("%s %d.%d.%d.%d%s",\
  95                                 x, (ntohl(a.s_addr)>>24)&0xFF,\
  96                                   (ntohl(a.s_addr)>>16)&0xFF,\
  97                                   (ntohl(a.s_addr)>>8)&0xFF,\
  98                                   (ntohl(a.s_addr))&0xFF, y);
  99
 100 u_short ip_id;
 101
 102 #ifdef MBUF_STRESS_TEST
 103 int mbuf_frag_size = 0;
 104 SYSCTL_INT(_net_inet_ip, OID_AUTO, mbuf_frag_size, CTLFLAG_RW,
 105         &mbuf_frag_size, 0, "Fragment outgoing mbufs to this size");
 106 #endif
 107
 108 static struct mbuf *ip_insertoptions(struct mbuf *, struct mbuf *, int *);
 109 static struct ifnet *ip_multicast_if(struct in_addr *, int *);
 110 static void     ip_mloopback
 111         (struct ifnet *, struct mbuf *, struct sockaddr_in *, int);
 112 static int      ip_getmoptions
 113         (struct sockopt *, struct ip_moptions *);
 114 static int      ip_pcbopts(int, struct mbuf **, struct mbuf *);
 115 static int      ip_setmoptions
 116         (struct sockopt *, struct ip_moptions **);
 117
 118 int     ip_optcopy(struct ip *, struct ip *);
 119
 120 extern  int route_assert_owner_access;
 121
 122 extern  struct protosw inetsw[];
 123
 124 static int
 125 ip_localforward(struct mbuf *m, const struct sockaddr_in *dst, int hlen)
 126 {
 127         struct in_ifaddr_container *iac;
 128
 129         /*
 130          * We need to figure out if we have been forwarded to a local
 131          * socket.  If so, then we should somehow "loop back" to
 132          * ip_input(), and get directed to the PCB as if we had received
 133          * this packet.  This is because it may be difficult to identify
 134          * the packets you want to forward until they are being output
 135          * and have selected an interface (e.g. locally initiated
 136          * packets).  If we used the loopback inteface, we would not be
 137          * able to control what happens as the packet runs through
 138          * ip_input() as it is done through a ISR.
 139          */
 140         LIST_FOREACH(iac, INADDR_HASH(dst->sin_addr.s_addr), ia_hash) {
 141                 /*
 142                  * If the addr to forward to is one of ours, we pretend
 143                  * to be the destination for this packet.
 144                  */
 145                 if (IA_SIN(iac->ia)->sin_addr.s_addr == dst->sin_addr.s_addr)
 146                         break;
 147         }
 148         if (iac != NULL) {
 149                 struct ip *ip;
 150
 151                 if (m->m_pkthdr.rcvif == NULL)
 152                         m->m_pkthdr.rcvif = ifunit("lo0");
 153                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 154                         m->m_pkthdr.csum_flags |= CSUM_DATA_VALID |
 155                                                   CSUM_PSEUDO_HDR;
 156                         m->m_pkthdr.csum_data = 0xffff;
 157                 }
 158                 m->m_pkthdr.csum_flags |= CSUM_IP_CHECKED | CSUM_IP_VALID;
 159
 160                 /*
 161                  * Make sure that the IP header is in one mbuf,
 162                  * required by ip_input
 163                  */
 164                 if (m->m_len < hlen) {
 165                         m = m_pullup(m, hlen);
 166                         if (m == NULL) {
 167                                 /* The packet was freed; we are done */
 168                                 return 1;
 169                         }
 170                 }
 171                 ip = mtod(m, struct ip *);
 172
 173                 ip->ip_len = htons(ip->ip_len);
 174                 ip->ip_off = htons(ip->ip_off);
 175                 ip_input(m);
 176
 177                 return 1; /* The packet gets forwarded locally */
 178         }
 179         return 0;
 180 }
 181
 182 /*
 183  * IP output.  The packet in mbuf chain m contains a skeletal IP
 184  * header (with len, off, ttl, proto, tos, src, dst).
 185  * The mbuf chain containing the packet will be freed.
 186  * The mbuf opt, if present, will not be freed.
 187  */
 188 int
 189 ip_output(struct mbuf *m0, struct mbuf *opt, struct route *ro,
 190           int flags, struct ip_moptions *imo, struct inpcb *inp)
 191 {
 192         struct ip *ip;
 193         struct ifnet *ifp = NULL;       /* keep compiler happy */
 194         struct mbuf *m;
 195         int hlen = sizeof(struct ip);
 196         int len, error = 0;
 197         struct sockaddr_in *dst = NULL; /* keep compiler happy */
 198         struct in_ifaddr *ia = NULL;
 199         int isbroadcast, sw_csum;
 200         struct in_addr pkt_dst;
 201         struct route iproute;
 202         struct m_tag *mtag;
 203 #ifdef IPSEC
 204         struct secpolicy *sp = NULL;
 205         struct socket *so = inp ? inp->inp_socket : NULL;
 206 #endif
 207 #ifdef FAST_IPSEC
 208         struct secpolicy *sp = NULL;
 209         struct tdb_ident *tdbi;
 210 #endif /* FAST_IPSEC */
 211         struct sockaddr_in *next_hop = NULL;
 212         int src_was_INADDR_ANY = 0;     /* as the name says... */
 213
 214         m = m0;
 215         M_ASSERTPKTHDR(m);
 216
 217         if (ro == NULL) {
 218                 ro = &iproute;
 219                 bzero(ro, sizeof *ro);
 220         } else if (ro->ro_rt != NULL && ro->ro_rt->rt_cpuid != mycpuid) {
 221                 if (flags & IP_DEBUGROUTE) {
 222                         if (route_assert_owner_access) {
 223                                 panic("ip_output: "
 224                                       "rt rt_cpuid %d accessed on cpu %d\n",
 225                                       ro->ro_rt->rt_cpuid, mycpuid);
 226                         } else {
 227                                 kprintf("ip_output: "
 228                                         "rt rt_cpuid %d accessed on cpu %d\n",
 229                                         ro->ro_rt->rt_cpuid, mycpuid);
 230                                 print_backtrace(-1);
 231                         }
 232                 }
 233
 234                 /*
 235                  * XXX
 236                  * If the cached rtentry's owner CPU is not the current CPU,
 237                  * then don't touch the cached rtentry (remote free is too
 238                  * expensive in this context); just relocate the route.
 239                  */
 240                 ro = &iproute;
 241                 bzero(ro, sizeof *ro);
 242         }
 243
 244         if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) {
 245                 /* Next hop */
 246                 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
 247                 KKASSERT(mtag != NULL);
 248                 next_hop = m_tag_data(mtag);
 249         }
 250
 251         if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) {
 252                 struct dn_pkt *dn_pkt;
 253
 254                 /* Extract info from dummynet tag */
 255                 mtag = m_tag_find(m, PACKET_TAG_DUMMYNET, NULL);
 256                 KKASSERT(mtag != NULL);
 257                 dn_pkt = m_tag_data(mtag);
 258
 259                 /*
 260                  * The packet was already tagged, so part of the
 261                  * processing was already done, and we need to go down.
 262                  * Get the calculated parameters from the tag.
 263                  */
 264                 ifp = dn_pkt->ifp;
 265
 266                 KKASSERT(ro == &iproute);
 267                 *ro = dn_pkt->ro; /* structure copy */
 268                 KKASSERT(ro->ro_rt == NULL || ro->ro_rt->rt_cpuid == mycpuid);
 269
 270                 dst = dn_pkt->dn_dst;
 271                 if (dst == (struct sockaddr_in *)&(dn_pkt->ro.ro_dst)) {
 272                         /* If 'dst' points into dummynet tag, adjust it */
 273                         dst = (struct sockaddr_in *)&(ro->ro_dst);
 274                 }
 275
 276                 ip = mtod(m, struct ip *);
 277                 hlen = IP_VHL_HL(ip->ip_vhl) << 2 ;
 278                 if (ro->ro_rt)
 279                         ia = ifatoia(ro->ro_rt->rt_ifa);
 280                 goto sendit;
 281         }
 282
 283         if (opt) {
 284                 len = 0;
 285                 m = ip_insertoptions(m, opt, &len);
 286                 if (len != 0)
 287                         hlen = len;
 288         }
 289         ip = mtod(m, struct ip *);
 290
 291         /*
 292          * Fill in IP header.
 293          */
 294         if (!(flags & (IP_FORWARDING|IP_RAWOUTPUT))) {
 295                 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, hlen >> 2);
 296                 ip->ip_off &= IP_DF;
 297                 ip->ip_id = ip_newid();
 298                 ipstat.ips_localout++;
 299         } else {
 300                 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 301         }
 302
 303 reroute:
 304         pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst;
 305
 306         dst = (struct sockaddr_in *)&ro->ro_dst;
 307         /*
 308          * If there is a cached route,
 309          * check that it is to the same destination
 310          * and is still up.  If not, free it and try again.
 311          * The address family should also be checked in case of sharing the
 312          * cache with IPv6.
 313          */
 314         if (ro->ro_rt &&
 315             (!(ro->ro_rt->rt_flags & RTF_UP) ||
 316              dst->sin_family != AF_INET ||
 317              dst->sin_addr.s_addr != pkt_dst.s_addr)) {
 318                 rtfree(ro->ro_rt);
 319                 ro->ro_rt = NULL;
 320         }
 321         if (ro->ro_rt == NULL) {
 322                 bzero(dst, sizeof *dst);
 323                 dst->sin_family = AF_INET;
 324                 dst->sin_len = sizeof *dst;
 325                 dst->sin_addr = pkt_dst;
 326         }
 327         /*
 328          * If routing to interface only,
 329          * short circuit routing lookup.
 330          */
 331         if (flags & IP_ROUTETOIF) {
 332                 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL &&
 333                     (ia = ifatoia(ifa_ifwithnet(sintosa(dst)))) == NULL) {
 334                         ipstat.ips_noroute++;
 335                         error = ENETUNREACH;
 336                         goto bad;
 337                 }
 338                 ifp = ia->ia_ifp;
 339                 ip->ip_ttl = 1;
 340                 isbroadcast = in_broadcast(dst->sin_addr, ifp);
 341         } else if (IN_MULTICAST(ntohl(pkt_dst.s_addr)) &&
 342                    imo != NULL && imo->imo_multicast_ifp != NULL) {
 343                 /*
 344                  * Bypass the normal routing lookup for multicast
 345                  * packets if the interface is specified.
 346                  */
 347                 ifp = imo->imo_multicast_ifp;
 348                 ia = IFP_TO_IA(ifp);
 349                 isbroadcast = 0;        /* fool gcc */
 350         } else {
 351                 /*
 352                  * If this is the case, we probably don't want to allocate
 353                  * a protocol-cloned route since we didn't get one from the
 354                  * ULP.  This lets TCP do its thing, while not burdening
 355                  * forwarding or ICMP with the overhead of cloning a route.
 356                  * Of course, we still want to do any cloning requested by
 357                  * the link layer, as this is probably required in all cases
 358                  * for correct operation (as it is for ARP).
 359                  */
 360                 if (ro->ro_rt == NULL)
 361                         rtalloc_ign(ro, RTF_PRCLONING);
 362                 if (ro->ro_rt == NULL) {
 363                         ipstat.ips_noroute++;
 364                         error = EHOSTUNREACH;
 365                         goto bad;
 366                 }
 367                 ia = ifatoia(ro->ro_rt->rt_ifa);
 368                 ifp = ro->ro_rt->rt_ifp;
 369                 ro->ro_rt->rt_use++;
 370                 if (ro->ro_rt->rt_flags & RTF_GATEWAY)
 371                         dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway;
 372                 if (ro->ro_rt->rt_flags & RTF_HOST)
 373                         isbroadcast = (ro->ro_rt->rt_flags & RTF_BROADCAST);
 374                 else
 375                         isbroadcast = in_broadcast(dst->sin_addr, ifp);
 376         }
 377         if (IN_MULTICAST(ntohl(pkt_dst.s_addr))) {
 378                 struct in_multi *inm;
 379
 380                 m->m_flags |= M_MCAST;
 381                 /*
 382                  * IP destination address is multicast.  Make sure "dst"
 383                  * still points to the address in "ro".  (It may have been
 384                  * changed to point to a gateway address, above.)
 385                  */
 386                 dst = (struct sockaddr_in *)&ro->ro_dst;
 387                 /*
 388                  * See if the caller provided any multicast options
 389                  */
 390                 if (imo != NULL) {
 391                         ip->ip_ttl = imo->imo_multicast_ttl;
 392                         if (imo->imo_multicast_vif != -1) {
 393                                 ip->ip_src.s_addr =
 394                                     ip_mcast_src ?
 395                                     ip_mcast_src(imo->imo_multicast_vif) :
 396                                     INADDR_ANY;
 397                         }
 398                 } else {
 399                         ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL;
 400                 }
 401                 /*
 402                  * Confirm that the outgoing interface supports multicast.
 403                  */
 404                 if ((imo == NULL) || (imo->imo_multicast_vif == -1)) {
 405                         if (!(ifp->if_flags & IFF_MULTICAST)) {
 406                                 ipstat.ips_noroute++;
 407                                 error = ENETUNREACH;
 408                                 goto bad;
 409                         }
 410                 }
 411                 /*
 412                  * If source address not specified yet, use address
 413                  * of outgoing interface.
 414                  */
 415                 if (ip->ip_src.s_addr == INADDR_ANY) {
 416                         /* Interface may have no addresses. */
 417                         if (ia != NULL)
 418                                 ip->ip_src = IA_SIN(ia)->sin_addr;
 419                 }
 420
 421                 IN_LOOKUP_MULTI(pkt_dst, ifp, inm);
 422                 if (inm != NULL &&
 423                     (imo == NULL || imo->imo_multicast_loop)) {
 424                         /*
 425                          * If we belong to the destination multicast group
 426                          * on the outgoing interface, and the caller did not
 427                          * forbid loopback, loop back a copy.
 428                          */
 429                         ip_mloopback(ifp, m, dst, hlen);
 430                 } else {
 431                         /*
 432                          * If we are acting as a multicast router, perform
 433                          * multicast forwarding as if the packet had just
 434                          * arrived on the interface to which we are about
 435                          * to send.  The multicast forwarding function
 436                          * recursively calls this function, using the
 437                          * IP_FORWARDING flag to prevent infinite recursion.
 438                          *
 439                          * Multicasts that are looped back by ip_mloopback(),
 440                          * above, will be forwarded by the ip_input() routine,
 441                          * if necessary.
 442                          */
 443                         if (ip_mrouter && !(flags & IP_FORWARDING)) {
 444                                 /*
 445                                  * If rsvp daemon is not running, do not
 446                                  * set ip_moptions. This ensures that the packet
 447                                  * is multicast and not just sent down one link
 448                                  * as prescribed by rsvpd.
 449                                  */
 450                                 if (!rsvp_on)
 451                                         imo = NULL;
 452                                 if (ip_mforward) {
 453                                         get_mplock();
 454                                         if (ip_mforward(ip, ifp, m, imo) != 0) {
 455                                                 m_freem(m);
 456                                                 rel_mplock();
 457                                                 goto done;
 458                                         }
 459                                         rel_mplock();
 460                                 }
 461                         }
 462                 }
 463
 464                 /*
 465                  * Multicasts with a time-to-live of zero may be looped-
 466                  * back, above, but must not be transmitted on a network.
 467                  * Also, multicasts addressed to the loopback interface
 468                  * are not sent -- the above call to ip_mloopback() will
 469                  * loop back a copy if this host actually belongs to the
 470                  * destination group on the loopback interface.
 471                  */
 472                 if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) {
 473                         m_freem(m);
 474                         goto done;
 475                 }
 476
 477                 goto sendit;
 478         } else {
 479                 m->m_flags &= ~M_MCAST;
 480         }
 481
 482         /*
 483          * If the source address is not specified yet, use the address
 484          * of the outoing interface. In case, keep note we did that, so
 485          * if the the firewall changes the next-hop causing the output
 486          * interface to change, we can fix that.
 487          */
 488         if (ip->ip_src.s_addr == INADDR_ANY || src_was_INADDR_ANY) {
 489                 /* Interface may have no addresses. */
 490                 if (ia != NULL) {
 491                         ip->ip_src = IA_SIN(ia)->sin_addr;
 492                         src_was_INADDR_ANY = 1;
 493                 }
 494         }
 495
 496         /*
 497          * Look for broadcast address and
 498          * verify user is allowed to send
 499          * such a packet.
 500          */
 501         if (isbroadcast) {
 502                 if (!(ifp->if_flags & IFF_BROADCAST)) {
 503                         error = EADDRNOTAVAIL;
 504                         goto bad;
 505                 }
 506                 if (!(flags & IP_ALLOWBROADCAST)) {
 507                         error = EACCES;
 508                         goto bad;
 509                 }
 510                 /* don't allow broadcast messages to be fragmented */
 511                 if (ip->ip_len > ifp->if_mtu) {
 512                         error = EMSGSIZE;
 513                         goto bad;
 514                 }
 515                 m->m_flags |= M_BCAST;
 516         } else {
 517                 m->m_flags &= ~M_BCAST;
 518         }
 519
 520 sendit:
 521 #ifdef IPSEC
 522         /* get SP for this packet */
 523         if (so == NULL)
 524                 sp = ipsec4_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, flags, &error);
 525         else
 526                 sp = ipsec4_getpolicybysock(m, IPSEC_DIR_OUTBOUND, so, &error);
 527
 528         if (sp == NULL) {
 529                 ipsecstat.out_inval++;
 530                 goto bad;
 531         }
 532
 533         error = 0;
 534
 535         /* check policy */
 536         switch (sp->policy) {
 537         case IPSEC_POLICY_DISCARD:
 538                 /*
 539                  * This packet is just discarded.
 540                  */
 541                 ipsecstat.out_polvio++;
 542                 goto bad;
 543
 544         case IPSEC_POLICY_BYPASS:
 545         case IPSEC_POLICY_NONE:
 546         case IPSEC_POLICY_TCP:
 547                 /* no need to do IPsec. */
 548                 goto skip_ipsec;
 549
 550         case IPSEC_POLICY_IPSEC:
 551                 if (sp->req == NULL) {
 552                         /* acquire a policy */
 553                         error = key_spdacquire(sp);
 554                         goto bad;
 555                 }
 556                 break;
 557
 558         case IPSEC_POLICY_ENTRUST:
 559         default:
 560                 kprintf("ip_output: Invalid policy found. %d\n", sp->policy);
 561         }
 562     {
 563         struct ipsec_output_state state;
 564         bzero(&state, sizeof state);
 565         state.m = m;
 566         if (flags & IP_ROUTETOIF) {
 567                 state.ro = &iproute;
 568                 bzero(&iproute, sizeof iproute);
 569         } else
 570                 state.ro = ro;
 571         state.dst = (struct sockaddr *)dst;
 572
 573         ip->ip_sum = 0;
 574
 575         /*
 576          * XXX
 577          * delayed checksums are not currently compatible with IPsec
 578          */
 579         if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 580                 in_delayed_cksum(m);
 581                 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
 582         }
 583
 584         ip->ip_len = htons(ip->ip_len);
 585         ip->ip_off = htons(ip->ip_off);
 586
 587         error = ipsec4_output(&state, sp, flags);
 588
 589         m = state.m;
 590         if (flags & IP_ROUTETOIF) {
 591                 /*
 592                  * if we have tunnel mode SA, we may need to ignore
 593                  * IP_ROUTETOIF.
 594                  */
 595                 if (state.ro != &iproute || state.ro->ro_rt != NULL) {
 596                         flags &= ~IP_ROUTETOIF;
 597                         ro = state.ro;
 598                 }
 599         } else
 600                 ro = state.ro;
 601         dst = (struct sockaddr_in *)state.dst;
 602         if (error) {
 603                 /* mbuf is already reclaimed in ipsec4_output. */
 604                 m0 = NULL;
 605                 switch (error) {
 606                 case EHOSTUNREACH:
 607                 case ENETUNREACH:
 608                 case EMSGSIZE:
 609                 case ENOBUFS:
 610                 case ENOMEM:
 611                         break;
 612                 default:
 613                         kprintf("ip4_output (ipsec): error code %d\n", error);
 614                         /*fall through*/
 615                 case ENOENT:
 616                         /* don't show these error codes to the user */
 617                         error = 0;
 618                         break;
 619                 }
 620                 goto bad;
 621         }
 622     }
 623
 624         /* be sure to update variables that are affected by ipsec4_output() */
 625         ip = mtod(m, struct ip *);
 626 #ifdef _IP_VHL
 627         hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 628 #else
 629         hlen = ip->ip_hl << 2;
 630 #endif
 631         if (ro->ro_rt == NULL) {
 632                 if (!(flags & IP_ROUTETOIF)) {
 633                         kprintf("ip_output: "
 634                                 "can't update route after IPsec processing\n");
 635                         error = EHOSTUNREACH;   /*XXX*/
 636                         goto bad;
 637                 }
 638         } else {
 639                 ia = ifatoia(ro->ro_rt->rt_ifa);
 640                 ifp = ro->ro_rt->rt_ifp;
 641         }
 642
 643         /* make it flipped, again. */
 644         ip->ip_len = ntohs(ip->ip_len);
 645         ip->ip_off = ntohs(ip->ip_off);
 646 skip_ipsec:
 647 #endif /*IPSEC*/
 648 #ifdef FAST_IPSEC
 649         /*
 650          * Check the security policy (SP) for the packet and, if
 651          * required, do IPsec-related processing.  There are two
 652          * cases here; the first time a packet is sent through
 653          * it will be untagged and handled by ipsec4_checkpolicy.
 654          * If the packet is resubmitted to ip_output (e.g. after
 655          * AH, ESP, etc. processing), there will be a tag to bypass
 656          * the lookup and related policy checking.
 657          */
 658         mtag = m_tag_find(m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
 659         crit_enter();
 660         if (mtag != NULL) {
 661                 tdbi = (struct tdb_ident *)m_tag_data(mtag);
 662                 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
 663                 if (sp == NULL)
 664                         error = -EINVAL;        /* force silent drop */
 665                 m_tag_delete(m, mtag);
 666         } else {
 667                 sp = ipsec4_checkpolicy(m, IPSEC_DIR_OUTBOUND, flags,
 668                                         &error, inp);
 669         }
 670         /*
 671          * There are four return cases:
 672          *    sp != NULL                    apply IPsec policy
 673          *    sp == NULL, error == 0        no IPsec handling needed
 674          *    sp == NULL, error == -EINVAL  discard packet w/o error
 675          *    sp == NULL, error != 0        discard packet, report error
 676          */
 677         if (sp != NULL) {
 678                 /* Loop detection, check if ipsec processing already done */
 679                 KASSERT(sp->req != NULL, ("ip_output: no ipsec request"));
 680                 for (mtag = m_tag_first(m); mtag != NULL;
 681                      mtag = m_tag_next(m, mtag)) {
 682                         if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
 683                                 continue;
 684                         if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
 685                             mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
 686                                 continue;
 687                         /*
 688                          * Check if policy has an SA associated with it.
 689                          * This can happen when an SP has yet to acquire
 690                          * an SA; e.g. on first reference.  If it occurs,
 691                          * then we let ipsec4_process_packet do its thing.
 692                          */
 693                         if (sp->req->sav == NULL)
 694                                 break;
 695                         tdbi = (struct tdb_ident *)m_tag_data(mtag);
 696                         if (tdbi->spi == sp->req->sav->spi &&
 697                             tdbi->proto == sp->req->sav->sah->saidx.proto &&
 698                             bcmp(&tdbi->dst, &sp->req->sav->sah->saidx.dst,
 699                                  sizeof(union sockaddr_union)) == 0) {
 700                                 /*
 701                                  * No IPsec processing is needed, free
 702                                  * reference to SP.
 703                                  *
 704                                  * NB: null pointer to avoid free at
 705                                  *     done: below.
 706                                  */
 707                                 KEY_FREESP(&sp), sp = NULL;
 708                                 crit_exit();
 709                                 goto spd_done;
 710                         }
 711                 }
 712
 713                 /*
 714                  * Do delayed checksums now because we send before
 715                  * this is done in the normal processing path.
 716                  */
 717                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 718                         in_delayed_cksum(m);
 719                         m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
 720                 }
 721
 722                 ip->ip_len = htons(ip->ip_len);
 723                 ip->ip_off = htons(ip->ip_off);
 724
 725                 /* NB: callee frees mbuf */
 726                 error = ipsec4_process_packet(m, sp->req, flags, 0);
 727                 /*
 728                  * Preserve KAME behaviour: ENOENT can be returned
 729                  * when an SA acquire is in progress.  Don't propagate
 730                  * this to user-level; it confuses applications.
 731                  *
 732                  * XXX this will go away when the SADB is redone.
 733                  */
 734                 if (error == ENOENT)
 735                         error = 0;
 736                 crit_exit();
 737                 goto done;
 738         } else {
 739                 crit_exit();
 740
 741                 if (error != 0) {
 742                         /*
 743                          * Hack: -EINVAL is used to signal that a packet
 744                          * should be silently discarded.  This is typically
 745                          * because we asked key management for an SA and
 746                          * it was delayed (e.g. kicked up to IKE).
 747                          */
 748                         if (error == -EINVAL)
 749                                 error = 0;
 750                         goto bad;
 751                 } else {
 752                         /* No IPsec processing for this packet. */
 753                 }
 754 #ifdef notyet
 755                 /*
 756                  * If deferred crypto processing is needed, check that
 757                  * the interface supports it.
 758                  */
 759                 mtag = m_tag_find(m, PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED, NULL);
 760                 if (mtag != NULL && !(ifp->if_capenable & IFCAP_IPSEC)) {
 761                         /* notify IPsec to do its own crypto */
 762                         ipsp_skipcrypto_unmark((struct tdb_ident *)m_tag_data(mtag));
 763                         error = EHOSTUNREACH;
 764                         goto bad;
 765                 }
 766 #endif
 767         }
 768 spd_done:
 769 #endif /* FAST_IPSEC */
 770
 771         /* We are already being fwd'd from a firewall. */
 772         if (next_hop != NULL)
 773                 goto pass;
 774
 775         /* No pfil hooks */
 776         if (!pfil_has_hooks(&inet_pfil_hook)) {
 777                 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) {
 778                         /*
 779                          * Strip dummynet tags from stranded packets
 780                          */
 781                         mtag = m_tag_find(m, PACKET_TAG_DUMMYNET, NULL);
 782                         KKASSERT(mtag != NULL);
 783                         m_tag_delete(m, mtag);
 784                         m->m_pkthdr.fw_flags &= ~DUMMYNET_MBUF_TAGGED;
 785                 }
 786                 goto pass;
 787         }
 788
 789         /*
 790          * IpHack's section.
 791          * - Xlate: translate packet's addr/port (NAT).
 792          * - Firewall: deny/allow/etc.
 793          * - Wrap: fake packet's addr/port <unimpl.>
 794          * - Encapsulate: put it in another IP and send out. <unimp.>
 795          */
 796
 797         /*
 798          * Run through list of hooks for output packets.
 799          */
 800         error = pfil_run_hooks(&inet_pfil_hook, &m, ifp, PFIL_OUT);
 801         if (error != 0 || m == NULL)
 802                 goto done;
 803         ip = mtod(m, struct ip *);
 804
 805         if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) {
 806                 /*
 807                  * Check dst to make sure it is directly reachable on the
 808                  * interface we previously thought it was.
 809                  * If it isn't (which may be likely in some situations) we have
 810                  * to re-route it (ie, find a route for the next-hop and the
 811                  * associated interface) and set them here. This is nested
 812                  * forwarding which in most cases is undesirable, except where
 813                  * such control is nigh impossible. So we do it here.
 814                  * And I'm babbling.
 815                  */
 816                 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
 817                 KKASSERT(mtag != NULL);
 818                 next_hop = m_tag_data(mtag);
 819
 820                 /*
 821                  * Try local forwarding first
 822                  */
 823                 if (ip_localforward(m, next_hop, hlen))
 824                         goto done;
 825
 826                 /*
 827                  * Relocate the route based on next_hop.
 828                  * If the current route is inp's cache, keep it untouched.
 829                  */
 830                 if (ro == &iproute && ro->ro_rt != NULL) {
 831                         RTFREE(ro->ro_rt);
 832                         ro->ro_rt = NULL;
 833                 }
 834                 ro = &iproute;
 835                 bzero(ro, sizeof *ro);
 836
 837                 /*
 838                  * Forwarding to broadcast address is not allowed.
 839                  * XXX Should we follow IP_ROUTETOIF?
 840                  */
 841                 flags &= ~(IP_ALLOWBROADCAST | IP_ROUTETOIF);
 842
 843                 /* We are doing forwarding now */
 844                 flags |= IP_FORWARDING;
 845
 846                 goto reroute;
 847         }
 848
 849         if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) {
 850                 struct dn_pkt *dn_pkt;
 851
 852                 mtag = m_tag_find(m, PACKET_TAG_DUMMYNET, NULL);
 853                 KKASSERT(mtag != NULL);
 854                 dn_pkt = m_tag_data(mtag);
 855
 856                 /*
 857                  * Under certain cases it is not possible to recalculate
 858                  * 'ro' and 'dst', let alone 'flags', so just save them in
 859                  * dummynet tag and avoid the possible wrong reculcalation
 860                  * when we come back to ip_output() again.
 861                  *
 862                  * All other parameters have been already used and so they
 863                  * are not needed anymore.
 864                  * XXX if the ifp is deleted while a pkt is in dummynet,
 865                  * we are in trouble! (TODO use ifnet_detach_event)
 866                  *
 867                  * We need to copy *ro because for ICMP pkts (and maybe
 868                  * others) the caller passed a pointer into the stack;
 869                  * dst might also be a pointer into *ro so it needs to
 870                  * be updated.
 871                  */
 872                 dn_pkt->ro = *ro;
 873                 if (ro->ro_rt)
 874                         ro->ro_rt->rt_refcnt++;
 875                 if (dst == (struct sockaddr_in *)&ro->ro_dst) {
 876                         /* 'dst' points into 'ro' */
 877                         dst = (struct sockaddr_in *)&(dn_pkt->ro.ro_dst);
 878                 }
 879                 dn_pkt->dn_dst = dst;
 880                 dn_pkt->flags = flags;
 881
 882                 ip_dn_queue(m);
 883                 goto done;
 884         }
 885 pass:
 886         /* 127/8 must not appear on wire - RFC1122. */
 887         if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
 888             (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
 889                 if (!(ifp->if_flags & IFF_LOOPBACK)) {
 890                         ipstat.ips_badaddr++;
 891                         error = EADDRNOTAVAIL;
 892                         goto bad;
 893                 }
 894         }
 895
 896         if ((m->m_pkthdr.csum_flags & CSUM_TSO) == 0) {
 897                 m->m_pkthdr.csum_flags |= CSUM_IP;
 898                 sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_hwassist;
 899                 if (sw_csum & CSUM_DELAY_DATA) {
 900                         in_delayed_cksum(m);
 901                         sw_csum &= ~CSUM_DELAY_DATA;
 902                 }
 903                 m->m_pkthdr.csum_flags &= ifp->if_hwassist;
 904         } else {
 905                 sw_csum = 0;
 906         }
 907         m->m_pkthdr.csum_iphlen = hlen;
 908
 909         /*
 910          * If small enough for interface, or the interface will take
 911          * care of the fragmentation or segmentation for us, can just
 912          * send directly.
 913          */
 914         if (ip->ip_len <= ifp->if_mtu ||
 915             ((ifp->if_hwassist & CSUM_FRAGMENT) && !(ip->ip_off & IP_DF)) ||
 916             (m->m_pkthdr.csum_flags & CSUM_TSO)) {
 917                 ip->ip_len = htons(ip->ip_len);
 918                 ip->ip_off = htons(ip->ip_off);
 919                 ip->ip_sum = 0;
 920                 if (sw_csum & CSUM_DELAY_IP) {
 921                         if (ip->ip_vhl == IP_VHL_BORING)
 922                                 ip->ip_sum = in_cksum_hdr(ip);
 923                         else
 924                                 ip->ip_sum = in_cksum(m, hlen);
 925                 }
 926
 927                 /* Record statistics for this interface address. */
 928                 if (!(flags & IP_FORWARDING) && ia) {
 929                         IFA_STAT_INC(&ia->ia_ifa, opackets, 1);
 930                         IFA_STAT_INC(&ia->ia_ifa, obytes, m->m_pkthdr.len);
 931                 }
 932
 933 #ifdef IPSEC
 934                 /* clean ipsec history once it goes out of the node */
 935                 ipsec_delaux(m);
 936 #endif
 937
 938 #ifdef MBUF_STRESS_TEST
 939                 if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size) {
 940                         struct mbuf *m1, *m2;
 941                         int length, tmp;
 942
 943                         tmp = length = m->m_pkthdr.len;
 944
 945                         while ((length -= mbuf_frag_size) >= 1) {
 946                                 m1 = m_split(m, length, MB_DONTWAIT);
 947                                 if (m1 == NULL)
 948                                         break;
 949                                 m2 = m;
 950                                 while (m2->m_next != NULL)
 951                                         m2 = m2->m_next;
 952                                 m2->m_next = m1;
 953                         }
 954                         m->m_pkthdr.len = tmp;
 955                 }
 956 #endif
 957
 958 #ifdef MPLS
 959                 if (!mpls_output_process(m, ro->ro_rt))
 960                         goto done;
 961 #endif
 962                 error = ifp->if_output(ifp, m, (struct sockaddr *)dst,
 963                                        ro->ro_rt);
 964                 goto done;
 965         }
 966
 967         if (ip->ip_off & IP_DF) {
 968                 error = EMSGSIZE;
 969                 /*
 970                  * This case can happen if the user changed the MTU
 971                  * of an interface after enabling IP on it.  Because
 972                  * most netifs don't keep track of routes pointing to
 973                  * them, there is no way for one to update all its
 974                  * routes when the MTU is changed.
 975                  */
 976                 if ((ro->ro_rt->rt_flags & (RTF_UP | RTF_HOST)) &&
 977                     !(ro->ro_rt->rt_rmx.rmx_locks & RTV_MTU) &&
 978                     (ro->ro_rt->rt_rmx.rmx_mtu > ifp->if_mtu)) {
 979                         ro->ro_rt->rt_rmx.rmx_mtu = ifp->if_mtu;
 980                 }
 981                 ipstat.ips_cantfrag++;
 982                 goto bad;
 983         }
 984
 985         /*
 986          * Too large for interface; fragment if possible. If successful,
 987          * on return, m will point to a list of packets to be sent.
 988          */
 989         error = ip_fragment(ip, &m, ifp->if_mtu, ifp->if_hwassist, sw_csum);
 990         if (error)
 991                 goto bad;
 992         for (; m; m = m0) {
 993                 m0 = m->m_nextpkt;
 994                 m->m_nextpkt = NULL;
 995 #ifdef IPSEC
 996                 /* clean ipsec history once it goes out of the node */
 997                 ipsec_delaux(m);
 998 #endif
 999                 if (error == 0) {
1000                         /* Record statistics for this interface address. */
1001                         if (ia != NULL) {
1002                                 IFA_STAT_INC(&ia->ia_ifa, opackets, 1);
1003                                 IFA_STAT_INC(&ia->ia_ifa, obytes,
1004                                     m->m_pkthdr.len);
1005                         }
1006 #ifdef MPLS
1007                         if (!mpls_output_process(m, ro->ro_rt))
1008                                 continue;
1009 #endif
1010                         error = ifp->if_output(ifp, m, (struct sockaddr *)dst,
1011                                                ro->ro_rt);
1012                 } else {
1013                         m_freem(m);
1014                 }
1015         }
1016
1017         if (error == 0)
1018                 ipstat.ips_fragmented++;
1019
1020 done:
1021         if (ro == &iproute && ro->ro_rt != NULL) {
1022                 RTFREE(ro->ro_rt);
1023                 ro->ro_rt = NULL;
1024         }
1025 #ifdef IPSEC
1026         if (sp != NULL) {
1027                 KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
1028                         kprintf("DP ip_output call free SP:%p\n", sp));
1029                 key_freesp(sp);
1030         }
1031 #endif
1032 #ifdef FAST_IPSEC
1033         if (sp != NULL)
1034                 KEY_FREESP(&sp);
1035 #endif
1036         return (error);
1037 bad:
1038         m_freem(m);
1039         goto done;
1040 }
1041
1042 /*
1043  * Create a chain of fragments which fit the given mtu. m_frag points to the
1044  * mbuf to be fragmented; on return it points to the chain with the fragments.
1045  * Return 0 if no error. If error, m_frag may contain a partially built
1046  * chain of fragments that should be freed by the caller.
1047  *
1048  * if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist)
1049  * sw_csum contains the delayed checksums flags (e.g., CSUM_DELAY_IP).
1050  */
1051 int
1052 ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu,
1053             u_long if_hwassist_flags, int sw_csum)
1054 {
1055         int error = 0;
1056         int hlen = IP_VHL_HL(ip->ip_vhl) << 2;
1057         int len = (mtu - hlen) & ~7;    /* size of payload in each fragment */
1058         int off;
1059         struct mbuf *m0 = *m_frag;      /* the original packet          */
1060         int firstlen;
1061         struct mbuf **mnext;
1062         int nfrags;
1063
1064         if (ip->ip_off & IP_DF) {       /* Fragmentation not allowed */
1065                 ipstat.ips_cantfrag++;
1066                 return EMSGSIZE;
1067         }
1068
1069         /*
1070          * Must be able to put at least 8 bytes per fragment.
1071          */
1072         if (len < 8)
1073                 return EMSGSIZE;
1074
1075         /*
1076          * If the interface will not calculate checksums on
1077          * fragmented packets, then do it here.
1078          */
1079         if ((m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA) &&
1080             !(if_hwassist_flags & CSUM_IP_FRAGS)) {
1081                 in_delayed_cksum(m0);
1082                 m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
1083         }
1084
1085         if (len > PAGE_SIZE) {
1086                 /*
1087                  * Fragment large datagrams such that each segment
1088                  * contains a multiple of PAGE_SIZE amount of data,
1089                  * plus headers. This enables a receiver to perform
1090                  * page-flipping zero-copy optimizations.
1091                  *
1092                  * XXX When does this help given that sender and receiver
1093                  * could have different page sizes, and also mtu could
1094                  * be less than the receiver's page size ?
1095                  */
1096                 int newlen;
1097                 struct mbuf *m;
1098
1099                 for (m = m0, off = 0; m && (off+m->m_len) <= mtu; m = m->m_next)
1100                         off += m->m_len;
1101
1102                 /*
1103                  * firstlen (off - hlen) must be aligned on an
1104                  * 8-byte boundary
1105                  */
1106                 if (off < hlen)
1107                         goto smart_frag_failure;
1108                 off = ((off - hlen) & ~7) + hlen;
1109                 newlen = (~PAGE_MASK) & mtu;
1110                 if ((newlen + sizeof(struct ip)) > mtu) {
1111                         /* we failed, go back the default */
1112 smart_frag_failure:
1113                         newlen = len;
1114                         off = hlen + len;
1115                 }
1116                 len = newlen;
1117
1118         } else {
1119                 off = hlen + len;
1120         }
1121
1122         firstlen = off - hlen;
1123         mnext = &m0->m_nextpkt;         /* pointer to next packet */
1124
1125         /*
1126          * Loop through length of segment after first fragment,
1127          * make new header and copy data of each part and link onto chain.
1128          * Here, m0 is the original packet, m is the fragment being created.
1129          * The fragments are linked off the m_nextpkt of the original
1130          * packet, which after processing serves as the first fragment.
1131          */
1132         for (nfrags = 1; off < ip->ip_len; off += len, nfrags++) {
1133                 struct ip *mhip;        /* ip header on the fragment */
1134                 struct mbuf *m;
1135                 int mhlen = sizeof(struct ip);
1136
1137                 MGETHDR(m, MB_DONTWAIT, MT_HEADER);
1138                 if (m == NULL) {
1139                         error = ENOBUFS;
1140                         ipstat.ips_odropped++;
1141                         goto done;
1142                 }
1143                 m->m_flags |= (m0->m_flags & M_MCAST) | M_FRAG;
1144                 /*
1145                  * In the first mbuf, leave room for the link header, then
1146                  * copy the original IP header including options. The payload
1147                  * goes into an additional mbuf chain returned by m_copy().
1148                  */
1149                 m->m_data += max_linkhdr;
1150                 mhip = mtod(m, struct ip *);
1151                 *mhip = *ip;
1152                 if (hlen > sizeof(struct ip)) {
1153                         mhlen = ip_optcopy(ip, mhip) + sizeof(struct ip);
1154                         mhip->ip_vhl = IP_MAKE_VHL(IPVERSION, mhlen >> 2);
1155                 }
1156                 m->m_len = mhlen;
1157                 /* XXX do we need to add ip->ip_off below ? */
1158                 mhip->ip_off = ((off - hlen) >> 3) + ip->ip_off;
1159                 if (off + len >= ip->ip_len) {  /* last fragment */
1160                         len = ip->ip_len - off;
1161                         m->m_flags |= M_LASTFRAG;
1162                 } else
1163                         mhip->ip_off |= IP_MF;
1164                 mhip->ip_len = htons((u_short)(len + mhlen));
1165                 m->m_next = m_copy(m0, off, len);
1166                 if (m->m_next == NULL) {                /* copy failed */
1167                         m_free(m);
1168                         error = ENOBUFS;        /* ??? */
1169                         ipstat.ips_odropped++;
1170                         goto done;
1171                 }
1172                 m->m_pkthdr.len = mhlen + len;
1173                 m->m_pkthdr.rcvif = NULL;
1174                 m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags;
1175                 m->m_pkthdr.csum_iphlen = mhlen;
1176                 mhip->ip_off = htons(mhip->ip_off);
1177                 mhip->ip_sum = 0;
1178                 if (sw_csum & CSUM_DELAY_IP)
1179                         mhip->ip_sum = in_cksum(m, mhlen);
1180                 *mnext = m;
1181                 mnext = &m->m_nextpkt;
1182         }
1183         ipstat.ips_ofragments += nfrags;
1184
1185         /* set first marker for fragment chain */
1186         m0->m_flags |= M_FIRSTFRAG | M_FRAG;
1187         m0->m_pkthdr.csum_data = nfrags;
1188
1189         /*
1190          * Update first fragment by trimming what's been copied out
1191          * and updating header.
1192          */
1193         m_adj(m0, hlen + firstlen - ip->ip_len);
1194         m0->m_pkthdr.len = hlen + firstlen;
1195         ip->ip_len = htons((u_short)m0->m_pkthdr.len);
1196         ip->ip_off |= IP_MF;
1197         ip->ip_off = htons(ip->ip_off);
1198         ip->ip_sum = 0;
1199         if (sw_csum & CSUM_DELAY_IP)
1200                 ip->ip_sum = in_cksum(m0, hlen);
1201
1202 done:
1203         *m_frag = m0;
1204         return error;
1205 }
1206
1207 void
1208 in_delayed_cksum(struct mbuf *m)
1209 {
1210         struct ip *ip;
1211         u_short csum, offset;
1212
1213         ip = mtod(m, struct ip *);
1214         offset = IP_VHL_HL(ip->ip_vhl) << 2 ;
1215         csum = in_cksum_skip(m, ip->ip_len, offset);
1216         if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0)
1217                 csum = 0xffff;
1218         offset += m->m_pkthdr.csum_data;        /* checksum offset */
1219
1220         if (offset + sizeof(u_short) > m->m_len) {
1221                 kprintf("delayed m_pullup, m->len: %d  off: %d  p: %d\n",
1222                     m->m_len, offset, ip->ip_p);
1223                 /*
1224                  * XXX
1225                  * this shouldn't happen, but if it does, the
1226                  * correct behavior may be to insert the checksum
1227                  * in the existing chain instead of rearranging it.
1228                  */
1229                 m = m_pullup(m, offset + sizeof(u_short));
1230         }
1231         *(u_short *)(m->m_data + offset) = csum;
1232 }
1233
1234 /*
1235  * Insert IP options into preformed packet.
1236  * Adjust IP destination as required for IP source routing,
1237  * as indicated by a non-zero in_addr at the start of the options.
1238  *
1239  * XXX This routine assumes that the packet has no options in place.
1240  */
1241 static struct mbuf *
1242 ip_insertoptions(struct mbuf *m, struct mbuf *opt, int *phlen)
1243 {
1244         struct ipoption *p = mtod(opt, struct ipoption *);
1245         struct mbuf *n;
1246         struct ip *ip = mtod(m, struct ip *);
1247         unsigned optlen;
1248
1249         optlen = opt->m_len - sizeof p->ipopt_dst;
1250         if (optlen + (u_short)ip->ip_len > IP_MAXPACKET) {
1251                 *phlen = 0;
1252                 return (m);             /* XXX should fail */
1253         }
1254         if (p->ipopt_dst.s_addr)
1255                 ip->ip_dst = p->ipopt_dst;
1256         if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) {
1257                 MGETHDR(n, MB_DONTWAIT, MT_HEADER);
1258                 if (n == NULL) {
1259                         *phlen = 0;
1260                         return (m);
1261                 }
1262                 n->m_pkthdr.rcvif = NULL;
1263                 n->m_pkthdr.len = m->m_pkthdr.len + optlen;
1264                 m->m_len -= sizeof(struct ip);
1265                 m->m_data += sizeof(struct ip);
1266                 n->m_next = m;
1267                 m = n;
1268                 m->m_len = optlen + sizeof(struct ip);
1269                 m->m_data += max_linkhdr;
1270                 memcpy(mtod(m, void *), ip, sizeof(struct ip));
1271         } else {
1272                 m->m_data -= optlen;
1273                 m->m_len += optlen;
1274                 m->m_pkthdr.len += optlen;
1275                 ovbcopy(ip, mtod(m, caddr_t), sizeof(struct ip));
1276         }
1277         ip = mtod(m, struct ip *);
1278         bcopy(p->ipopt_list, ip + 1, optlen);
1279         *phlen = sizeof(struct ip) + optlen;
1280         ip->ip_vhl = IP_MAKE_VHL(IPVERSION, *phlen >> 2);
1281         ip->ip_len += optlen;
1282         return (m);
1283 }
1284
1285 /*
1286  * Copy options from ip to jp,
1287  * omitting those not copied during fragmentation.
1288  */
1289 int
1290 ip_optcopy(struct ip *ip, struct ip *jp)
1291 {
1292         u_char *cp, *dp;
1293         int opt, optlen, cnt;
1294
1295         cp = (u_char *)(ip + 1);
1296         dp = (u_char *)(jp + 1);
1297         cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip);
1298         for (; cnt > 0; cnt -= optlen, cp += optlen) {
1299                 opt = cp[0];
1300                 if (opt == IPOPT_EOL)
1301                         break;
1302                 if (opt == IPOPT_NOP) {
1303                         /* Preserve for IP mcast tunnel's LSRR alignment. */
1304                         *dp++ = IPOPT_NOP;
1305                         optlen = 1;
1306                         continue;
1307                 }
1308
1309                 KASSERT(cnt >= IPOPT_OLEN + sizeof *cp,
1310                     ("ip_optcopy: malformed ipv4 option"));
1311                 optlen = cp[IPOPT_OLEN];
1312                 KASSERT(optlen >= IPOPT_OLEN + sizeof *cp && optlen <= cnt,
1313                     ("ip_optcopy: malformed ipv4 option"));
1314
1315                 /* bogus lengths should have been caught by ip_dooptions */
1316                 if (optlen > cnt)
1317                         optlen = cnt;
1318                 if (IPOPT_COPIED(opt)) {
1319                         bcopy(cp, dp, optlen);
1320                         dp += optlen;
1321                 }
1322         }
1323         for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++)
1324                 *dp++ = IPOPT_EOL;
1325         return (optlen);
1326 }
1327
1328 /*
1329  * IP socket option processing.
1330  */
1331 void
1332 ip_ctloutput(netmsg_t msg)
1333 {
1334         struct socket *so = msg->base.nm_so;
1335         struct sockopt *sopt = msg->ctloutput.nm_sopt;
1336         struct  inpcb *inp = so->so_pcb;
1337         int     error, optval;
1338
1339         error = optval = 0;
1340         if (sopt->sopt_level != IPPROTO_IP) {
1341                 error = EINVAL;
1342                 goto done;
1343         }
1344
1345         switch (sopt->sopt_dir) {
1346         case SOPT_SET:
1347                 switch (sopt->sopt_name) {
1348                 case IP_OPTIONS:
1349 #ifdef notyet
1350                 case IP_RETOPTS:
1351 #endif
1352                 {
1353                         struct mbuf *m;
1354                         if (sopt->sopt_valsize > MLEN) {
1355                                 error = EMSGSIZE;
1356                                 break;
1357                         }
1358                         MGET(m, sopt->sopt_td ? MB_WAIT : MB_DONTWAIT, MT_HEADER);
1359                         if (m == NULL) {
1360                                 error = ENOBUFS;
1361                                 break;
1362                         }
1363                         m->m_len = sopt->sopt_valsize;
1364                         error = soopt_to_kbuf(sopt, mtod(m, void *), m->m_len,
1365                                               m->m_len);
1366                         error = ip_pcbopts(sopt->sopt_name,
1367                                            &inp->inp_options, m);
1368                         goto done;
1369                 }
1370
1371                 case IP_TOS:
1372                 case IP_TTL:
1373                 case IP_MINTTL:
1374                 case IP_RECVOPTS:
1375                 case IP_RECVRETOPTS:
1376                 case IP_RECVDSTADDR:
1377                 case IP_RECVIF:
1378                 case IP_RECVTTL:
1379                 case IP_FAITH:
1380                         error = soopt_to_kbuf(sopt, &optval, sizeof optval,
1381                                              sizeof optval);
1382                         if (error)
1383                                 break;
1384                         switch (sopt->sopt_name) {
1385                         case IP_TOS:
1386                                 inp->inp_ip_tos = optval;
1387                                 break;
1388
1389                         case IP_TTL:
1390                                 inp->inp_ip_ttl = optval;
1391                                 break;
1392                         case IP_MINTTL:
1393                                 if (optval >= 0 && optval <= MAXTTL)
1394                                         inp->inp_ip_minttl = optval;
1395                                 else
1396                                         error = EINVAL;
1397                                 break;
1398 #define OPTSET(bit) \
1399         if (optval) \
1400                 inp->inp_flags |= bit; \
1401         else \
1402                 inp->inp_flags &= ~bit;
1403
1404                         case IP_RECVOPTS:
1405                                 OPTSET(INP_RECVOPTS);
1406                                 break;
1407
1408                         case IP_RECVRETOPTS:
1409                                 OPTSET(INP_RECVRETOPTS);
1410                                 break;
1411
1412                         case IP_RECVDSTADDR:
1413                                 OPTSET(INP_RECVDSTADDR);
1414                                 break;
1415
1416                         case IP_RECVIF:
1417                                 OPTSET(INP_RECVIF);
1418                                 break;
1419
1420                         case IP_RECVTTL:
1421                                 OPTSET(INP_RECVTTL);
1422                                 break;
1423
1424                         case IP_FAITH:
1425                                 OPTSET(INP_FAITH);
1426                                 break;
1427                         }
1428                         break;
1429 #undef OPTSET
1430
1431                 case IP_MULTICAST_IF:
1432                 case IP_MULTICAST_VIF:
1433                 case IP_MULTICAST_TTL:
1434                 case IP_MULTICAST_LOOP:
1435                 case IP_ADD_MEMBERSHIP:
1436                 case IP_DROP_MEMBERSHIP:
1437                         error = ip_setmoptions(sopt, &inp->inp_moptions);
1438                         break;
1439
1440                 case IP_PORTRANGE:
1441                         error = soopt_to_kbuf(sopt, &optval, sizeof optval,
1442                                             sizeof optval);
1443                         if (error)
1444                                 break;
1445
1446                         switch (optval) {
1447                         case IP_PORTRANGE_DEFAULT:
1448                                 inp->inp_flags &= ~(INP_LOWPORT);
1449                                 inp->inp_flags &= ~(INP_HIGHPORT);
1450                                 break;
1451
1452                         case IP_PORTRANGE_HIGH:
1453                                 inp->inp_flags &= ~(INP_LOWPORT);
1454                                 inp->inp_flags |= INP_HIGHPORT;
1455                                 break;
1456
1457                         case IP_PORTRANGE_LOW:
1458                                 inp->inp_flags &= ~(INP_HIGHPORT);
1459                                 inp->inp_flags |= INP_LOWPORT;
1460                                 break;
1461
1462                         default:
1463                                 error = EINVAL;
1464                                 break;
1465                         }
1466                         break;
1467
1468 #if defined(IPSEC) || defined(FAST_IPSEC)
1469                 case IP_IPSEC_POLICY:
1470                 {
1471                         caddr_t req;
1472                         size_t len = 0;
1473                         int priv;
1474                         struct mbuf *m;
1475                         int optname;
1476
1477                         if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */
1478                                 break;
1479                         soopt_to_mbuf(sopt, m);
1480                         priv = (sopt->sopt_td != NULL &&
1481                                 priv_check(sopt->sopt_td, PRIV_ROOT) != 0) ? 0 : 1;
1482                         req = mtod(m, caddr_t);
1483                         len = m->m_len;
1484                         optname = sopt->sopt_name;
1485                         error = ipsec4_set_policy(inp, optname, req, len, priv);
1486                         m_freem(m);
1487                         break;
1488                 }
1489 #endif /*IPSEC*/
1490
1491                 default:
1492                         error = ENOPROTOOPT;
1493                         break;
1494                 }
1495                 break;
1496
1497         case SOPT_GET:
1498                 switch (sopt->sopt_name) {
1499                 case IP_OPTIONS:
1500                 case IP_RETOPTS:
1501                         if (inp->inp_options)
1502                                 soopt_from_kbuf(sopt, mtod(inp->inp_options,
1503                                                            char *),
1504                                                 inp->inp_options->m_len);
1505                         else
1506                                 sopt->sopt_valsize = 0;
1507                         break;
1508
1509                 case IP_TOS:
1510                 case IP_TTL:
1511                 case IP_MINTTL:
1512                 case IP_RECVOPTS:
1513                 case IP_RECVRETOPTS:
1514                 case IP_RECVDSTADDR:
1515                 case IP_RECVTTL:
1516                 case IP_RECVIF:
1517                 case IP_PORTRANGE:
1518                 case IP_FAITH:
1519                         switch (sopt->sopt_name) {
1520
1521                         case IP_TOS:
1522                                 optval = inp->inp_ip_tos;
1523                                 break;
1524
1525                         case IP_TTL:
1526                                 optval = inp->inp_ip_ttl;
1527                                 break;
1528                         case IP_MINTTL:
1529                                 optval = inp->inp_ip_minttl;
1530                                 break;
1531
1532 #define OPTBIT(bit)     (inp->inp_flags & bit ? 1 : 0)
1533
1534                         case IP_RECVOPTS:
1535                                 optval = OPTBIT(INP_RECVOPTS);
1536                                 break;
1537
1538                         case IP_RECVRETOPTS:
1539                                 optval = OPTBIT(INP_RECVRETOPTS);
1540                                 break;
1541
1542                         case IP_RECVDSTADDR:
1543                                 optval = OPTBIT(INP_RECVDSTADDR);
1544                                 break;
1545
1546                         case IP_RECVTTL:
1547                                 optval = OPTBIT(INP_RECVTTL);
1548                                 break;
1549
1550                         case IP_RECVIF:
1551                                 optval = OPTBIT(INP_RECVIF);
1552                                 break;
1553
1554                         case IP_PORTRANGE:
1555                                 if (inp->inp_flags & INP_HIGHPORT)
1556                                         optval = IP_PORTRANGE_HIGH;
1557                                 else if (inp->inp_flags & INP_LOWPORT)
1558                                         optval = IP_PORTRANGE_LOW;
1559                                 else
1560                                         optval = 0;
1561                                 break;
1562
1563                         case IP_FAITH:
1564                                 optval = OPTBIT(INP_FAITH);
1565                                 break;
1566                         }
1567                         soopt_from_kbuf(sopt, &optval, sizeof optval);
1568                         break;
1569
1570                 case IP_MULTICAST_IF:
1571                 case IP_MULTICAST_VIF:
1572                 case IP_MULTICAST_TTL:
1573                 case IP_MULTICAST_LOOP:
1574                 case IP_ADD_MEMBERSHIP:
1575                 case IP_DROP_MEMBERSHIP:
1576                         error = ip_getmoptions(sopt, inp->inp_moptions);
1577                         break;
1578
1579 #if defined(IPSEC) || defined(FAST_IPSEC)
1580                 case IP_IPSEC_POLICY:
1581                 {
1582                         struct mbuf *m = NULL;
1583                         caddr_t req = NULL;
1584                         size_t len = 0;
1585
1586                         if (m != NULL) {
1587                                 req = mtod(m, caddr_t);
1588                                 len = m->m_len;
1589                         }
1590                         error = ipsec4_get_policy(so->so_pcb, req, len, &m);
1591                         if (error == 0)
1592                                 error = soopt_from_mbuf(sopt, m); /* XXX */
1593                         if (error == 0)
1594                                 m_freem(m);
1595                         break;
1596                 }
1597 #endif /*IPSEC*/
1598
1599                 default:
1600                         error = ENOPROTOOPT;
1601                         break;
1602                 }
1603                 break;
1604         }
1605 done:
1606         lwkt_replymsg(&msg->lmsg, error);
1607 }
1608
1609 /*
1610  * Set up IP options in pcb for insertion in output packets.
1611  * Store in mbuf with pointer in pcbopt, adding pseudo-option
1612  * with destination address if source routed.
1613  */
1614 static int
1615 ip_pcbopts(int optname, struct mbuf **pcbopt, struct mbuf *m)
1616 {
1617         int cnt, optlen;
1618         u_char *cp;
1619         u_char opt;
1620
1621         /* turn off any old options */
1622         if (*pcbopt)
1623                 m_free(*pcbopt);
1624         *pcbopt = NULL;
1625         if (m == NULL || m->m_len == 0) {
1626                 /*
1627                  * Only turning off any previous options.
1628                  */
1629                 if (m != NULL)
1630                         m_free(m);
1631                 return (0);
1632         }
1633
1634         if (m->m_len % sizeof(int32_t))
1635                 goto bad;
1636         /*
1637          * IP first-hop destination address will be stored before
1638          * actual options; move other options back
1639          * and clear it when none present.
1640          */
1641         if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN])
1642                 goto bad;
1643         cnt = m->m_len;
1644         m->m_len += sizeof(struct in_addr);
1645         cp = mtod(m, u_char *) + sizeof(struct in_addr);
1646         ovbcopy(mtod(m, caddr_t), cp, cnt);
1647         bzero(mtod(m, caddr_t), sizeof(struct in_addr));
1648
1649         for (; cnt > 0; cnt -= optlen, cp += optlen) {
1650                 opt = cp[IPOPT_OPTVAL];
1651                 if (opt == IPOPT_EOL)
1652                         break;
1653                 if (opt == IPOPT_NOP)
1654                         optlen = 1;
1655                 else {
1656                         if (cnt < IPOPT_OLEN + sizeof *cp)
1657                                 goto bad;
1658                         optlen = cp[IPOPT_OLEN];
1659                         if (optlen < IPOPT_OLEN + sizeof *cp || optlen > cnt)
1660                                 goto bad;
1661                 }
1662                 switch (opt) {
1663
1664                 default:
1665                         break;
1666
1667                 case IPOPT_LSRR:
1668                 case IPOPT_SSRR:
1669                         /*
1670                          * user process specifies route as:
1671                          *      ->A->B->C->D
1672                          * D must be our final destination (but we can't
1673                          * check that since we may not have connected yet).
1674                          * A is first hop destination, which doesn't appear in
1675                          * actual IP option, but is stored before the options.
1676                          */
1677                         if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr))
1678                                 goto bad;
1679                         m->m_len -= sizeof(struct in_addr);
1680                         cnt -= sizeof(struct in_addr);
1681                         optlen -= sizeof(struct in_addr);
1682                         cp[IPOPT_OLEN] = optlen;
1683                         /*
1684                          * Move first hop before start of options.
1685                          */
1686                         bcopy(&cp[IPOPT_OFFSET+1], mtod(m, caddr_t),
1687                               sizeof(struct in_addr));
1688                         /*
1689                          * Then copy rest of options back
1690                          * to close up the deleted entry.
1691                          */
1692                         ovbcopy(&cp[IPOPT_OFFSET+1] + sizeof(struct in_addr),
1693                                 &cp[IPOPT_OFFSET+1],
1694                                 cnt - (IPOPT_MINOFF - 1));
1695                         break;
1696                 }
1697         }
1698         if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr))
1699                 goto bad;
1700         *pcbopt = m;
1701         return (0);
1702
1703 bad:
1704         m_free(m);
1705         return (EINVAL);
1706 }
1707
1708 /*
1709  * XXX
1710  * The whole multicast option thing needs to be re-thought.
1711  * Several of these options are equally applicable to non-multicast
1712  * transmission, and one (IP_MULTICAST_TTL) totally duplicates a
1713  * standard option (IP_TTL).
1714  */
1715
1716 /*
1717  * following RFC1724 section 3.3, 0.0.0.0/8 is interpreted as interface index.
1718  */
1719 static struct ifnet *
1720 ip_multicast_if(struct in_addr *a, int *ifindexp)
1721 {
1722         int ifindex;
1723         struct ifnet *ifp;
1724
1725         if (ifindexp)
1726                 *ifindexp = 0;
1727         if (ntohl(a->s_addr) >> 24 == 0) {
1728                 ifindex = ntohl(a->s_addr) & 0xffffff;
1729                 if (ifindex < 0 || if_index < ifindex)
1730                         return NULL;
1731                 ifp = ifindex2ifnet[ifindex];
1732                 if (ifindexp)
1733                         *ifindexp = ifindex;
1734         } else {
1735                 ifp = INADDR_TO_IFP(a);
1736         }
1737         return ifp;
1738 }
1739
1740 /*
1741  * Set the IP multicast options in response to user setsockopt().
1742  */
1743 static int
1744 ip_setmoptions(struct sockopt *sopt, struct ip_moptions **imop)
1745 {
1746         int error = 0;
1747         int i;
1748         struct in_addr addr;
1749         struct ip_mreq mreq;
1750         struct ifnet *ifp;
1751         struct ip_moptions *imo = *imop;
1752         int ifindex;
1753
1754         if (imo == NULL) {
1755                 /*
1756                  * No multicast option buffer attached to the pcb;
1757                  * allocate one and initialize to default values.
1758                  */
1759                 imo = kmalloc(sizeof *imo, M_IPMOPTS, M_WAITOK);
1760
1761                 *imop = imo;
1762                 imo->imo_multicast_ifp = NULL;
1763                 imo->imo_multicast_addr.s_addr = INADDR_ANY;
1764                 imo->imo_multicast_vif = -1;
1765                 imo->imo_multicast_ttl = IP_DEFAULT_MULTICAST_TTL;
1766                 imo->imo_multicast_loop = IP_DEFAULT_MULTICAST_LOOP;
1767                 imo->imo_num_memberships = 0;
1768         }
1769         switch (sopt->sopt_name) {
1770         /* store an index number for the vif you wanna use in the send */
1771         case IP_MULTICAST_VIF:
1772                 if (legal_vif_num == 0) {
1773                         error = EOPNOTSUPP;
1774                         break;
1775                 }
1776                 error = soopt_to_kbuf(sopt, &i, sizeof i, sizeof i);
1777                 if (error)
1778                         break;
1779                 if (!legal_vif_num(i) && (i != -1)) {
1780                         error = EINVAL;
1781                         break;
1782                 }
1783                 imo->imo_multicast_vif = i;
1784                 break;
1785
1786         case IP_MULTICAST_IF:
1787                 /*
1788                  * Select the interface for outgoing multicast packets.
1789                  */
1790                 error = soopt_to_kbuf(sopt, &addr, sizeof addr, sizeof addr);
1791                 if (error)
1792                         break;
1793
1794                 /*
1795                  * INADDR_ANY is used to remove a previous selection.
1796                  * When no interface is selected, a default one is
1797                  * chosen every time a multicast packet is sent.
1798                  */
1799                 if (addr.s_addr == INADDR_ANY) {
1800                         imo->imo_multicast_ifp = NULL;
1801                         break;
1802                 }
1803                 /*
1804                  * The selected interface is identified by its local
1805                  * IP address.  Find the interface and confirm that
1806                  * it supports multicasting.
1807                  */
1808                 crit_enter();
1809                 ifp = ip_multicast_if(&addr, &ifindex);
1810                 if (ifp == NULL || !(ifp->if_flags & IFF_MULTICAST)) {
1811                         crit_exit();
1812                         error = EADDRNOTAVAIL;
1813                         break;
1814                 }
1815                 imo->imo_multicast_ifp = ifp;
1816                 if (ifindex)
1817                         imo->imo_multicast_addr = addr;
1818                 else
1819                         imo->imo_multicast_addr.s_addr = INADDR_ANY;
1820                 crit_exit();
1821                 break;
1822
1823         case IP_MULTICAST_TTL:
1824                 /*
1825                  * Set the IP time-to-live for outgoing multicast packets.
1826                  * The original multicast API required a char argument,
1827                  * which is inconsistent with the rest of the socket API.
1828                  * We allow either a char or an int.
1829                  */
1830                 if (sopt->sopt_valsize == 1) {
1831                         u_char ttl;
1832                         error = soopt_to_kbuf(sopt, &ttl, 1, 1);
1833                         if (error)
1834                                 break;
1835                         imo->imo_multicast_ttl = ttl;
1836                 } else {
1837                         u_int ttl;
1838                         error = soopt_to_kbuf(sopt, &ttl, sizeof ttl, sizeof ttl);
1839                         if (error)
1840                                 break;
1841                         if (ttl > 255)
1842                                 error = EINVAL;
1843                         else
1844                                 imo->imo_multicast_ttl = ttl;
1845                 }
1846                 break;
1847
1848         case IP_MULTICAST_LOOP:
1849                 /*
1850                  * Set the loopback flag for outgoing multicast packets.
1851                  * Must be zero or one.  The original multicast API required a
1852                  * char argument, which is inconsistent with the rest
1853                  * of the socket API.  We allow either a char or an int.
1854                  */
1855                 if (sopt->sopt_valsize == 1) {
1856                         u_char loop;
1857
1858                         error = soopt_to_kbuf(sopt, &loop, 1, 1);
1859                         if (error)
1860                                 break;
1861                         imo->imo_multicast_loop = !!loop;
1862                 } else {
1863                         u_int loop;
1864
1865                         error = soopt_to_kbuf(sopt, &loop, sizeof loop,
1866                                             sizeof loop);
1867                         if (error)
1868                                 break;
1869                         imo->imo_multicast_loop = !!loop;
1870                 }
1871                 break;
1872
1873         case IP_ADD_MEMBERSHIP:
1874                 /*
1875                  * Add a multicast group membership.
1876                  * Group must be a valid IP multicast address.
1877                  */
1878                 error = soopt_to_kbuf(sopt, &mreq, sizeof mreq, sizeof mreq);
1879                 if (error)
1880                         break;
1881
1882                 if (!IN_MULTICAST(ntohl(mreq.imr_multiaddr.s_addr))) {
1883                         error = EINVAL;
1884                         break;
1885                 }
1886                 crit_enter();
1887                 /*
1888                  * If no interface address was provided, use the interface of
1889                  * the route to the given multicast address.
1890                  */
1891                 if (mreq.imr_interface.s_addr == INADDR_ANY) {
1892                         struct sockaddr_in dst;
1893                         struct rtentry *rt;
1894
1895                         bzero(&dst, sizeof(struct sockaddr_in));
1896                         dst.sin_len = sizeof(struct sockaddr_in);
1897                         dst.sin_family = AF_INET;
1898                         dst.sin_addr = mreq.imr_multiaddr;
1899                         rt = rtlookup((struct sockaddr *)&dst);
1900                         if (rt == NULL) {
1901                                 error = EADDRNOTAVAIL;
1902                                 crit_exit();
1903                                 break;
1904                         }
1905                         --rt->rt_refcnt;
1906                         ifp = rt->rt_ifp;
1907                 } else {
1908                         ifp = ip_multicast_if(&mreq.imr_interface, NULL);
1909                 }
1910
1911                 /*
1912                  * See if we found an interface, and confirm that it
1913                  * supports multicast.
1914                  */
1915                 if (ifp == NULL || !(ifp->if_flags & IFF_MULTICAST)) {
1916                         error = EADDRNOTAVAIL;
1917                         crit_exit();
1918                         break;
1919                 }
1920                 /*
1921                  * See if the membership already exists or if all the
1922                  * membership slots are full.
1923                  */
1924                 for (i = 0; i < imo->imo_num_memberships; ++i) {
1925                         if (imo->imo_membership[i]->inm_ifp == ifp &&
1926                             imo->imo_membership[i]->inm_addr.s_addr
1927                                                 == mreq.imr_multiaddr.s_addr)
1928                                 break;
1929                 }
1930                 if (i < imo->imo_num_memberships) {
1931                         error = EADDRINUSE;
1932                         crit_exit();
1933                         break;
1934                 }
1935                 if (i == IP_MAX_MEMBERSHIPS) {
1936                         error = ETOOMANYREFS;
1937                         crit_exit();
1938                         break;
1939                 }
1940                 /*
1941                  * Everything looks good; add a new record to the multicast
1942                  * address list for the given interface.
1943                  */
1944                 if ((imo->imo_membership[i] =
1945                      in_addmulti(&mreq.imr_multiaddr, ifp)) == NULL) {
1946                         error = ENOBUFS;
1947                         crit_exit();
1948                         break;
1949                 }
1950                 ++imo->imo_num_memberships;
1951                 crit_exit();
1952                 break;
1953
1954         case IP_DROP_MEMBERSHIP:
1955                 /*
1956                  * Drop a multicast group membership.
1957                  * Group must be a valid IP multicast address.
1958                  */
1959                 error = soopt_to_kbuf(sopt, &mreq, sizeof mreq, sizeof mreq);
1960                 if (error)
1961                         break;
1962
1963                 if (!IN_MULTICAST(ntohl(mreq.imr_multiaddr.s_addr))) {
1964                         error = EINVAL;
1965                         break;
1966                 }
1967
1968                 crit_enter();
1969                 /*
1970                  * If an interface address was specified, get a pointer
1971                  * to its ifnet structure.
1972                  */
1973                 if (mreq.imr_interface.s_addr == INADDR_ANY)
1974                         ifp = NULL;
1975                 else {
1976                         ifp = ip_multicast_if(&mreq.imr_interface, NULL);
1977                         if (ifp == NULL) {
1978                                 error = EADDRNOTAVAIL;
1979                                 crit_exit();
1980                                 break;
1981                         }
1982                 }
1983                 /*
1984                  * Find the membership in the membership array.
1985                  */
1986                 for (i = 0; i < imo->imo_num_memberships; ++i) {
1987                         if ((ifp == NULL ||
1988                              imo->imo_membership[i]->inm_ifp == ifp) &&
1989                             imo->imo_membership[i]->inm_addr.s_addr ==
1990                             mreq.imr_multiaddr.s_addr)
1991                                 break;
1992                 }
1993                 if (i == imo->imo_num_memberships) {
1994                         error = EADDRNOTAVAIL;
1995                         crit_exit();
1996                         break;
1997                 }
1998                 /*
1999                  * Give up the multicast address record to which the
2000                  * membership points.
2001                  */
2002                 in_delmulti(imo->imo_membership[i]);
2003                 /*
2004                  * Remove the gap in the membership array.
2005                  */
2006                 for (++i; i < imo->imo_num_memberships; ++i)
2007                         imo->imo_membership[i-1] = imo->imo_membership[i];
2008                 --imo->imo_num_memberships;
2009                 crit_exit();
2010                 break;
2011
2012         default:
2013                 error = EOPNOTSUPP;
2014                 break;
2015         }
2016
2017         /*
2018          * If all options have default values, no need to keep the mbuf.
2019          */
2020         if (imo->imo_multicast_ifp == NULL &&
2021             imo->imo_multicast_vif == -1 &&
2022             imo->imo_multicast_ttl == IP_DEFAULT_MULTICAST_TTL &&
2023             imo->imo_multicast_loop == IP_DEFAULT_MULTICAST_LOOP &&
2024             imo->imo_num_memberships == 0) {
2025                 kfree(*imop, M_IPMOPTS);
2026                 *imop = NULL;
2027         }
2028
2029         return (error);
2030 }
2031
2032 /*
2033  * Return the IP multicast options in response to user getsockopt().
2034  */
2035 static int
2036 ip_getmoptions(struct sockopt *sopt, struct ip_moptions *imo)
2037 {
2038         struct in_addr addr;
2039         struct in_ifaddr *ia;
2040         int error, optval;
2041         u_char coptval;
2042
2043         error = 0;
2044         switch (sopt->sopt_name) {
2045         case IP_MULTICAST_VIF:
2046                 if (imo != NULL)
2047                         optval = imo->imo_multicast_vif;
2048                 else
2049                         optval = -1;
2050                 soopt_from_kbuf(sopt, &optval, sizeof optval);
2051                 break;
2052
2053         case IP_MULTICAST_IF:
2054                 if (imo == NULL || imo->imo_multicast_ifp == NULL)
2055                         addr.s_addr = INADDR_ANY;
2056                 else if (imo->imo_multicast_addr.s_addr) {
2057                         /* return the value user has set */
2058                         addr = imo->imo_multicast_addr;
2059                 } else {
2060                         ia = IFP_TO_IA(imo->imo_multicast_ifp);
2061                         addr.s_addr = (ia == NULL) ? INADDR_ANY
2062                                 : IA_SIN(ia)->sin_addr.s_addr;
2063                 }
2064                 soopt_from_kbuf(sopt, &addr, sizeof addr);
2065                 break;
2066
2067         case IP_MULTICAST_TTL:
2068                 if (imo == NULL)
2069                         optval = coptval = IP_DEFAULT_MULTICAST_TTL;
2070                 else
2071                         optval = coptval = imo->imo_multicast_ttl;
2072                 if (sopt->sopt_valsize == 1)
2073                         soopt_from_kbuf(sopt, &coptval, 1);
2074                 else
2075                         soopt_from_kbuf(sopt, &optval, sizeof optval);
2076                 break;
2077
2078         case IP_MULTICAST_LOOP:
2079                 if (imo == NULL)
2080                         optval = coptval = IP_DEFAULT_MULTICAST_LOOP;
2081                 else
2082                         optval = coptval = imo->imo_multicast_loop;
2083                 if (sopt->sopt_valsize == 1)
2084                         soopt_from_kbuf(sopt, &coptval, 1);
2085                 else
2086                         soopt_from_kbuf(sopt, &optval, sizeof optval);
2087                 break;
2088
2089         default:
2090                 error = ENOPROTOOPT;
2091                 break;
2092         }
2093         return (error);
2094 }
2095
2096 /*
2097  * Discard the IP multicast options.
2098  */
2099 void
2100 ip_freemoptions(struct ip_moptions *imo)
2101 {
2102         int i;
2103
2104         if (imo != NULL) {
2105                 for (i = 0; i < imo->imo_num_memberships; ++i)
2106                         in_delmulti(imo->imo_membership[i]);
2107                 kfree(imo, M_IPMOPTS);
2108         }
2109 }
2110
2111 /*
2112  * Routine called from ip_output() to loop back a copy of an IP multicast
2113  * packet to the input queue of a specified interface.  Note that this
2114  * calls the output routine of the loopback "driver", but with an interface
2115  * pointer that might NOT be a loopback interface -- evil, but easier than
2116  * replicating that code here.
2117  */
2118 static void
2119 ip_mloopback(struct ifnet *ifp, struct mbuf *m, struct sockaddr_in *dst,
2120              int hlen)
2121 {
2122         struct ip *ip;
2123         struct mbuf *copym;
2124
2125         copym = m_copypacket(m, MB_DONTWAIT);
2126         if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen))
2127                 copym = m_pullup(copym, hlen);
2128         if (copym != NULL) {
2129                 /*
2130                  * if the checksum hasn't been computed, mark it as valid
2131                  */
2132                 if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
2133                         in_delayed_cksum(copym);
2134                         copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
2135                         copym->m_pkthdr.csum_flags |=
2136                             CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
2137                         copym->m_pkthdr.csum_data = 0xffff;
2138                 }
2139                 /*
2140                  * We don't bother to fragment if the IP length is greater
2141                  * than the interface's MTU.  Can this possibly matter?
2142                  */
2143                 ip = mtod(copym, struct ip *);
2144                 ip->ip_len = htons(ip->ip_len);
2145                 ip->ip_off = htons(ip->ip_off);
2146                 ip->ip_sum = 0;
2147                 if (ip->ip_vhl == IP_VHL_BORING) {
2148                         ip->ip_sum = in_cksum_hdr(ip);
2149                 } else {
2150                         ip->ip_sum = in_cksum(copym, hlen);
2151                 }
2152                 /*
2153                  * NB:
2154                  * It's not clear whether there are any lingering
2155                  * reentrancy problems in other areas which might
2156                  * be exposed by using ip_input directly (in
2157                  * particular, everything which modifies the packet
2158                  * in-place).  Yet another option is using the
2159                  * protosw directly to deliver the looped back
2160                  * packet.  For the moment, we'll err on the side
2161                  * of safety by using if_simloop().
2162                  */
2163 #if 1 /* XXX */
2164                 if (dst->sin_family != AF_INET) {
2165                         kprintf("ip_mloopback: bad address family %d\n",
2166                                                 dst->sin_family);
2167                         dst->sin_family = AF_INET;
2168                 }
2169 #endif
2170                 get_mplock();   /* is if_simloop() mpsafe yet? */
2171                 if_simloop(ifp, copym, dst->sin_family, 0);
2172                 rel_mplock();
2173         }
2174 }