bsd/netinet6/udp6_output.c

   1 /*
   2  * Copyright (c) 2000-2018 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29
  30 /*      $FreeBSD: src/sys/netinet6/udp6_output.c,v 1.1.2.3 2001/08/31 13:49:58 jlemon Exp $     */
  31 /*      $KAME: udp6_output.c,v 1.31 2001/05/21 16:39:15 jinmei Exp $    */
  32
  33 /*
  34  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
  35  * All rights reserved.
  36  *
  37  * Redistribution and use in source and binary forms, with or without
  38  * modification, are permitted provided that the following conditions
  39  * are met:
  40  * 1. Redistributions of source code must retain the above copyright
  41  *    notice, this list of conditions and the following disclaimer.
  42  * 2. Redistributions in binary form must reproduce the above copyright
  43  *    notice, this list of conditions and the following disclaimer in the
  44  *    documentation and/or other materials provided with the distribution.
  45  * 3. Neither the name of the project nor the names of its contributors
  46  *    may be used to endorse or promote products derived from this software
  47  *    without specific prior written permission.
  48  *
  49  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  50  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  51  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  52  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  53  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  54  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  55  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  56  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  57  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  58  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  59  * SUCH DAMAGE.
  60  */
  61
  62 /*
  63  * Copyright (c) 1982, 1986, 1989, 1993
  64  *      The Regents of the University of California.  All rights reserved.
  65  *
  66  * Redistribution and use in source and binary forms, with or without
  67  * modification, are permitted provided that the following conditions
  68  * are met:
  69  * 1. Redistributions of source code must retain the above copyright
  70  *    notice, this list of conditions and the following disclaimer.
  71  * 2. Redistributions in binary form must reproduce the above copyright
  72  *    notice, this list of conditions and the following disclaimer in the
  73  *    documentation and/or other materials provided with the distribution.
  74  * 3. All advertising materials mentioning features or use of this software
  75  *    must display the following acknowledgement:
  76  *      This product includes software developed by the University of
  77  *      California, Berkeley and its contributors.
  78  * 4. Neither the name of the University nor the names of its contributors
  79  *    may be used to endorse or promote products derived from this software
  80  *    without specific prior written permission.
  81  *
  82  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  83  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  84  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  85  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  86  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  87  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  88  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  89  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  90  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  91  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  92  * SUCH DAMAGE.
  93  *
  94  *      @(#)udp_var.h   8.1 (Berkeley) 6/10/93
  95  */
  96
  97 #include <sys/param.h>
  98 #include <sys/malloc.h>
  99 #include <sys/mbuf.h>
 100 #include <sys/protosw.h>
 101 #include <sys/socket.h>
 102 #include <sys/socketvar.h>
 103 #include <sys/sysctl.h>
 104 #include <sys/errno.h>
 105 #include <sys/stat.h>
 106 #include <sys/systm.h>
 107 #include <sys/proc.h>
 108 #include <sys/syslog.h>
 109
 110 #include <machine/endian.h>
 111
 112 #include <net/if.h>
 113 #include <net/route.h>
 114 #include <net/if_types.h>
 115 #include <net/ntstat.h>
 116
 117 #include <netinet/in.h>
 118 #include <netinet/in_var.h>
 119 #include <netinet/in_systm.h>
 120 #include <netinet/in_tclass.h>
 121 #include <netinet/ip.h>
 122 #include <netinet/ip_var.h>
 123 #include <netinet/in_pcb.h>
 124 #include <netinet/udp.h>
 125 #include <netinet/udp_var.h>
 126 #include <netinet/ip6.h>
 127 #include <netinet6/ip6_var.h>
 128 #include <netinet6/in6_pcb.h>
 129 #include <netinet6/udp6_var.h>
 130 #include <netinet/icmp6.h>
 131 #include <netinet6/ip6protosw.h>
 132
 133 #if NECP
 134 #include <net/necp.h>
 135 #endif /* NECP */
 136
 137 #include <net/net_osdep.h>
 138
 139 #if CONTENT_FILTER
 140 #include <net/content_filter.h>
 141 #endif /* CONTENT_FILTER */
 142
 143 /*
 144  * UDP protocol inplementation.
 145  * Per RFC 768, August, 1980.
 146  */
 147 extern int soreserveheadroom;
 148
 149 int
 150 udp6_output(struct in6pcb *in6p, struct mbuf *m, struct sockaddr *addr6,
 151     struct mbuf *control, struct proc *p)
 152 {
 153         u_int32_t ulen = m->m_pkthdr.len;
 154         u_int32_t plen = sizeof (struct udphdr) + ulen;
 155         struct ip6_hdr *ip6;
 156         struct udphdr *udp6;
 157         struct in6_addr *laddr, *faddr;
 158         u_short fport;
 159         int error = 0;
 160         struct ip6_pktopts opt, *optp = NULL;
 161         struct ip6_moptions *im6o;
 162         int af = AF_INET6, hlen = sizeof (struct ip6_hdr);
 163         int flags;
 164         struct sockaddr_in6 tmp;
 165         struct  in6_addr storage;
 166         int sotc = SO_TC_UNSPEC;
 167         int netsvctype = _NET_SERVICE_TYPE_UNSPEC;
 168         struct ip6_out_args ip6oa;
 169         struct flowadv *adv = &ip6oa.ip6oa_flowadv;
 170         struct socket *so = in6p->in6p_socket;
 171         struct route_in6 ro;
 172         int flowadv = 0;
 173 #if CONTENT_FILTER
 174         struct m_tag *cfil_tag = NULL;
 175         bool cfil_faddr_use = false;
 176         uint32_t cfil_so_state_change_cnt = 0;
 177         struct sockaddr *cfil_faddr = NULL;
 178         struct sockaddr_in6 *cfil_sin6 = NULL;
 179 #endif
 180
 181         bzero(&ip6oa, sizeof(ip6oa));
 182         ip6oa.ip6oa_boundif = IFSCOPE_NONE;
 183         ip6oa.ip6oa_flags = IP6OAF_SELECT_SRCIF;
 184
 185         /* Enable flow advisory only when connected */
 186         flowadv = (so->so_state & SS_ISCONNECTED) ? 1 : 0;
 187
 188         if (flowadv && INP_WAIT_FOR_IF_FEEDBACK(in6p)) {
 189                 error = ENOBUFS;
 190                 goto release;
 191         }
 192
 193         if (in6p->inp_flags & INP_BOUND_IF) {
 194                 ip6oa.ip6oa_boundif = in6p->inp_boundifp->if_index;
 195                 ip6oa.ip6oa_flags |= IP6OAF_BOUND_IF;
 196         }
 197         if (INP_NO_CELLULAR(in6p))
 198                 ip6oa.ip6oa_flags |= IP6OAF_NO_CELLULAR;
 199         if (INP_NO_EXPENSIVE(in6p))
 200                 ip6oa.ip6oa_flags |= IP6OAF_NO_EXPENSIVE;
 201         if (INP_AWDL_UNRESTRICTED(in6p))
 202                 ip6oa.ip6oa_flags |= IP6OAF_AWDL_UNRESTRICTED;
 203         if (INP_INTCOPROC_ALLOWED(in6p))
 204                 ip6oa.ip6oa_flags |= IP6OAF_INTCOPROC_ALLOWED;
 205
 206 #if CONTENT_FILTER
 207         /*
 208          * If socket is subject to UDP Content Filter and no addr is passed in,
 209          * retrieve CFIL saved state from mbuf and use it if necessary.
 210          */
 211         if (so->so_cfil_db && !addr6) {
 212                 cfil_tag = cfil_udp_get_socket_state(m, &cfil_so_state_change_cnt, NULL, &cfil_faddr);
 213                 if (cfil_tag) {
 214                         cfil_sin6 = (struct sockaddr_in6 *)(void *)cfil_faddr;
 215                         if ((so->so_state_change_cnt != cfil_so_state_change_cnt) &&
 216                                 (in6p->in6p_fport != cfil_sin6->sin6_port ||
 217                                  !IN6_ARE_ADDR_EQUAL(&in6p->in6p_faddr, &cfil_sin6->sin6_addr))) {
 218                                 /*
 219                                  * Socket is connected but socket state and dest addr/port changed.
 220                                  * We need to use the saved faddr info.
 221                                  */
 222                                 cfil_faddr_use = true;
 223                         }
 224                 }
 225         }
 226 #endif
 227
 228         if (control) {
 229                 sotc = so_tc_from_control(control, &netsvctype);
 230                 if ((error = ip6_setpktopts(control, &opt,
 231                     NULL, IPPROTO_UDP)) != 0)
 232                         goto release;
 233                 optp = &opt;
 234         } else
 235                 optp = in6p->in6p_outputopts;
 236
 237         if (sotc == SO_TC_UNSPEC) {
 238                 sotc = so->so_traffic_class;
 239                 netsvctype = so->so_netsvctype;
 240         }
 241         ip6oa.ip6oa_sotc = sotc;
 242         ip6oa.ip6oa_netsvctype = netsvctype;
 243
 244         if (addr6) {
 245                 /*
 246                  * IPv4 version of udp_output calls in_pcbconnect in this case,
 247                  * which has its costs.
 248                  *
 249                  * Since we saw no essential reason for calling in_pcbconnect,
 250                  * we get rid of such kind of logic, and call in6_selectsrc
 251                  * and in6_pcbsetport in order to fill in the local address
 252                  * and the local port.
 253                  */
 254                 struct sockaddr_in6 *sin6 =
 255                     (struct sockaddr_in6 *)(void *)addr6;
 256
 257                 if (sin6->sin6_port == 0) {
 258                         error = EADDRNOTAVAIL;
 259                         goto release;
 260                 }
 261
 262                 if (!IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_faddr)) {
 263                         /* how about ::ffff:0.0.0.0 case? */
 264                         error = EISCONN;
 265                         goto release;
 266                 }
 267
 268                 /* protect *sin6 from overwrites */
 269                 tmp = *sin6;
 270                 sin6 = &tmp;
 271
 272                 faddr = &sin6->sin6_addr;
 273                 fport = sin6->sin6_port; /* allow 0 port */
 274
 275                 if (IN6_IS_ADDR_V4MAPPED(faddr)) {
 276                         if ((in6p->in6p_flags & IN6P_IPV6_V6ONLY)) {
 277                                 /*
 278                                  * I believe we should explicitly discard the
 279                                  * packet when mapped addresses are disabled,
 280                                  * rather than send the packet as an IPv6 one.
 281                                  * If we chose the latter approach, the packet
 282                                  * might be sent out on the wire based on the
 283                                  * default route, the situation which we'd
 284                                  * probably want to avoid.
 285                                  * (20010421 jinmei@kame.net)
 286                                  */
 287                                 error = EINVAL;
 288                                 goto release;
 289                         } else {
 290                                 af = AF_INET;
 291                         }
 292                 }
 293
 294                 /* KAME hack: embed scopeid */
 295                 if (in6_embedscope(&sin6->sin6_addr, sin6, in6p, NULL,
 296                     optp) != 0) {
 297                         error = EINVAL;
 298                         goto release;
 299                 }
 300
 301                 if (!IN6_IS_ADDR_V4MAPPED(faddr)) {
 302                         laddr = in6_selectsrc(sin6, optp,
 303                             in6p, &in6p->in6p_route, NULL, &storage,
 304                             ip6oa.ip6oa_boundif, &error);
 305                 } else
 306                         laddr = &in6p->in6p_laddr;      /* XXX */
 307                 if (laddr == NULL) {
 308                         if (error == 0)
 309                                 error = EADDRNOTAVAIL;
 310                         goto release;
 311                 }
 312                 if (in6p->in6p_lport == 0 &&
 313                     (error = in6_pcbsetport(laddr, in6p, p, 0)) != 0)
 314                         goto release;
 315         } else {
 316                 if (IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_faddr)) {
 317                         error = ENOTCONN;
 318                         goto release;
 319                 }
 320                 laddr = &in6p->in6p_laddr;
 321                 faddr = &in6p->in6p_faddr;
 322                 fport = in6p->in6p_fport;
 323 #if CONTENT_FILTER
 324                 if (cfil_faddr_use)
 325                 {
 326                         faddr = &((struct sockaddr_in6 *)(void *)cfil_faddr)->sin6_addr;
 327                         fport = ((struct sockaddr_in6 *)(void *)cfil_faddr)->sin6_port;
 328
 329                         /* Do not use cached route */
 330                         ROUTE_RELEASE(&in6p->in6p_route);
 331                 }
 332 #endif
 333                 if (IN6_IS_ADDR_V4MAPPED(faddr)) {
 334                         if ((in6p->in6p_flags & IN6P_IPV6_V6ONLY)) {
 335                                 /*
 336                                  * XXX: this case would happen when the
 337                                  * application sets the V6ONLY flag after
 338                                  * connecting the foreign address.
 339                                  * Such applications should be fixed,
 340                                  * so we bark here.
 341                                  */
 342                                 log(LOG_INFO, "udp6_output: IPV6_V6ONLY "
 343                                     "option was set for a connected socket\n");
 344                                 error = EINVAL;
 345                                 goto release;
 346                         } else
 347                                 af = AF_INET;
 348                 }
 349
 350         }
 351
 352         if (in6p->inp_flowhash == 0)
 353                 in6p->inp_flowhash = inp_calc_flowhash(in6p);
 354         /* update flowinfo - RFC 6437 */
 355         if (in6p->inp_flow == 0 && in6p->in6p_flags & IN6P_AUTOFLOWLABEL) {
 356                 in6p->inp_flow &= ~IPV6_FLOWLABEL_MASK;
 357                 in6p->inp_flow |=
 358                     (htonl(in6p->inp_flowhash) & IPV6_FLOWLABEL_MASK);
 359         }
 360
 361         if (af == AF_INET)
 362                 hlen = sizeof (struct ip);
 363
 364         if (fport == htons(53) && !(so->so_flags1 & SOF1_DNS_COUNTED)) {
 365                 so->so_flags1 |= SOF1_DNS_COUNTED;
 366                 INC_ATOMIC_INT64_LIM(net_api_stats.nas_socket_inet_dgram_dns);
 367         }
 368
 369         /*
 370          * Calculate data length and get a mbuf
 371          * for UDP and IP6 headers.
 372          */
 373         M_PREPEND(m, hlen + sizeof (struct udphdr), M_DONTWAIT, 1);
 374         if (m == 0) {
 375                 error = ENOBUFS;
 376                 goto release;
 377         }
 378
 379         /*
 380          * Stuff checksum and output datagram.
 381          */
 382         udp6 = (struct udphdr *)(void *)(mtod(m, caddr_t) + hlen);
 383         udp6->uh_sport = in6p->in6p_lport; /* lport is always set in the PCB */
 384         udp6->uh_dport = fport;
 385         if (plen <= 0xffff)
 386                 udp6->uh_ulen = htons((u_short)plen);
 387         else
 388                 udp6->uh_ulen = 0;
 389         udp6->uh_sum = 0;
 390
 391         switch (af) {
 392         case AF_INET6:
 393                 ip6 = mtod(m, struct ip6_hdr *);
 394                 ip6->ip6_flow   = in6p->inp_flow & IPV6_FLOWINFO_MASK;
 395                 ip6->ip6_vfc    &= ~IPV6_VERSION_MASK;
 396                 ip6->ip6_vfc    |= IPV6_VERSION;
 397 #if 0           /* ip6_plen will be filled in ip6_output. */
 398                 ip6->ip6_plen   = htons((u_short)plen);
 399 #endif
 400                 ip6->ip6_nxt    = IPPROTO_UDP;
 401                 ip6->ip6_hlim   = in6_selecthlim(in6p, in6p->in6p_route.ro_rt ?
 402                     in6p->in6p_route.ro_rt->rt_ifp : NULL);
 403                 ip6->ip6_src    = *laddr;
 404                 ip6->ip6_dst    = *faddr;
 405
 406                 udp6->uh_sum = in6_pseudo(laddr, faddr,
 407                     htonl(plen + IPPROTO_UDP));
 408                 m->m_pkthdr.csum_flags = (CSUM_UDPIPV6|CSUM_ZERO_INVERT);
 409                 m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
 410
 411                 if (!IN6_IS_ADDR_UNSPECIFIED(laddr))
 412                         ip6oa.ip6oa_flags |= IP6OAF_BOUND_SRCADDR;
 413
 414                 flags = IPV6_OUTARGS;
 415
 416                 udp6stat.udp6s_opackets++;
 417
 418 #if NECP
 419                 {
 420                         necp_kernel_policy_id policy_id;
 421                         necp_kernel_policy_id skip_policy_id;
 422                         u_int32_t route_rule_id;
 423
 424                         /*
 425                          * We need a route to perform NECP route rule checks
 426                          */
 427                         if (net_qos_policy_restricted != 0 &&
 428                             ROUTE_UNUSABLE(&in6p->inp_route)) {
 429                                 struct sockaddr_in6 to;
 430                                 struct sockaddr_in6 from;
 431
 432                                 ROUTE_RELEASE(&in6p->inp_route);
 433
 434                                 bzero(&from, sizeof(struct sockaddr_in6));
 435                                 from.sin6_family = AF_INET6;
 436                                 from.sin6_len = sizeof(struct sockaddr_in6);
 437                                 from.sin6_addr = *laddr;
 438
 439                                 bzero(&to, sizeof(struct sockaddr_in6));
 440                                 to.sin6_family = AF_INET6;
 441                                 to.sin6_len = sizeof(struct sockaddr_in6);
 442                                 to.sin6_addr = *faddr;
 443
 444                                 in6p->inp_route.ro_dst.sa_family = AF_INET6;
 445                                 in6p->inp_route.ro_dst.sa_len = sizeof(struct sockaddr_in6);
 446                                 ((struct sockaddr_in6 *)(void *)&in6p->inp_route.ro_dst)->sin6_addr =
 447                                         *faddr;
 448
 449                                 rtalloc_scoped(&in6p->inp_route, ip6oa.ip6oa_boundif);
 450
 451                                 inp_update_necp_policy(in6p, (struct sockaddr *)&from,
 452                                     (struct sockaddr *)&to, ip6oa.ip6oa_boundif);
 453                                 in6p->inp_policyresult.results.qos_marking_gencount = 0;
 454                         }
 455
 456                         if (!necp_socket_is_allowed_to_send_recv_v6(in6p, in6p->in6p_lport, fport, laddr, faddr, NULL, &policy_id, &route_rule_id, &skip_policy_id)) {
 457                                 error = EHOSTUNREACH;
 458                                 goto release;
 459                         }
 460
 461                         necp_mark_packet_from_socket(m, in6p, policy_id, route_rule_id, skip_policy_id);
 462
 463                         if (net_qos_policy_restricted != 0) {
 464                                 necp_socket_update_qos_marking(in6p, in6p->in6p_route.ro_rt,
 465                                     NULL, route_rule_id);
 466                         }
 467                 }
 468 #endif /* NECP */
 469                 if ((so->so_flags1 & SOF1_QOSMARKING_ALLOWED))
 470                         ip6oa.ip6oa_flags |= IP6OAF_QOSMARKING_ALLOWED;
 471
 472 #if IPSEC
 473                 if (in6p->in6p_sp != NULL && ipsec_setsocket(m, so) != 0) {
 474                         error = ENOBUFS;
 475                         goto release;
 476                 }
 477 #endif /*IPSEC*/
 478
 479                 /* In case of IPv4-mapped address used in previous send */
 480                 if (ROUTE_UNUSABLE(&in6p->in6p_route) ||
 481                     rt_key(in6p->in6p_route.ro_rt)->sa_family != AF_INET6)
 482                         ROUTE_RELEASE(&in6p->in6p_route);
 483
 484                 /* Copy the cached route and take an extra reference */
 485                 in6p_route_copyout(in6p, &ro);
 486
 487                 set_packet_service_class(m, so, sotc, PKT_SCF_IPV6);
 488
 489                 m->m_pkthdr.pkt_flowsrc = FLOWSRC_INPCB;
 490                 m->m_pkthdr.pkt_flowid = in6p->inp_flowhash;
 491                 m->m_pkthdr.pkt_proto = IPPROTO_UDP;
 492                 m->m_pkthdr.pkt_flags |= (PKTF_FLOW_ID | PKTF_FLOW_LOCALSRC);
 493                 if (flowadv)
 494                         m->m_pkthdr.pkt_flags |= PKTF_FLOW_ADV;
 495                 m->m_pkthdr.tx_udp_pid = so->last_pid;
 496                 if (so->so_flags & SOF_DELEGATED)
 497                         m->m_pkthdr.tx_udp_e_pid = so->e_pid;
 498                 else
 499                         m->m_pkthdr.tx_udp_e_pid = 0;
 500
 501                 im6o = in6p->in6p_moptions;
 502                 if (im6o != NULL) {
 503                         IM6O_LOCK(im6o);
 504                         IM6O_ADDREF_LOCKED(im6o);
 505                         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) &&
 506                             im6o->im6o_multicast_ifp != NULL) {
 507                                 in6p->in6p_last_outifp =
 508                                     im6o->im6o_multicast_ifp;
 509                         }
 510                         IM6O_UNLOCK(im6o);
 511                 }
 512
 513                 in6p->inp_sndinprog_cnt++;
 514
 515                 socket_unlock(so, 0);
 516                 error = ip6_output(m, optp, &ro, flags, im6o, NULL, &ip6oa);
 517                 m = NULL;
 518                 socket_lock(so, 0);
 519
 520                 if (im6o != NULL)
 521                         IM6O_REMREF(im6o);
 522
 523                 if (error == 0 && nstat_collect) {
 524                         boolean_t cell, wifi, wired;
 525
 526                         if (in6p->in6p_route.ro_rt != NULL) {
 527                                 cell = IFNET_IS_CELLULAR(in6p->in6p_route.
 528                                     ro_rt->rt_ifp);
 529                                 wifi = (!cell && IFNET_IS_WIFI(in6p->in6p_route.
 530                                     ro_rt->rt_ifp));
 531                                 wired = (!wifi && IFNET_IS_WIRED(in6p->in6p_route.
 532                                     ro_rt->rt_ifp));
 533                         } else {
 534                                 cell = wifi = wired = FALSE;
 535                         }
 536                         INP_ADD_STAT(in6p, cell, wifi, wired, txpackets, 1);
 537                         INP_ADD_STAT(in6p, cell, wifi, wired, txbytes, ulen);
 538                         inp_set_activity_bitmap(in6p);
 539                 }
 540
 541                 if (flowadv && (adv->code == FADV_FLOW_CONTROLLED ||
 542                     adv->code == FADV_SUSPENDED)) {
 543                         /*
 544                          * Return an error to indicate
 545                          * that the packet has been dropped.
 546                          */
 547                         error = ENOBUFS;
 548                         inp_set_fc_state(in6p, adv->code);
 549                 }
 550
 551                 VERIFY(in6p->inp_sndinprog_cnt > 0);
 552                 if ( --in6p->inp_sndinprog_cnt == 0)
 553                         in6p->inp_flags &= ~(INP_FC_FEEDBACK);
 554
 555                 if (ro.ro_rt != NULL) {
 556                         struct ifnet *outif = ro.ro_rt->rt_ifp;
 557
 558                         so->so_pktheadroom = P2ROUNDUP(
 559                             sizeof(struct udphdr) +
 560                             hlen +
 561                             ifnet_hdrlen(outif) +
 562                             ifnet_mbuf_packetpreamblelen(outif),
 563                             sizeof(u_int32_t));
 564                 }
 565
 566                 /* Synchronize PCB cached route */
 567                 in6p_route_copyin(in6p, &ro);
 568
 569                 if (in6p->in6p_route.ro_rt != NULL) {
 570                         struct rtentry *rt = in6p->in6p_route.ro_rt;
 571                         struct ifnet *outif;
 572
 573                         if (rt->rt_flags & RTF_MULTICAST)
 574                                 rt = NULL;      /* unusable */
 575
 576 #if CONTENT_FILTER
 577                         /*
 578                          * Discard temporary route for cfil case
 579                          */
 580                         if (cfil_faddr_use)
 581                                 rt = NULL;      /* unusable */
 582 #endif
 583
 584                         /*
 585                          * Always discard the cached route for unconnected
 586                          * socket or if it is a multicast route.
 587                          */
 588                         if (rt == NULL)
 589                                 ROUTE_RELEASE(&in6p->in6p_route);
 590
 591                         /*
 592                          * If the destination route is unicast, update outif
 593                          * with that of the route interface used by IP.
 594                          */
 595                         if (rt != NULL &&
 596                             (outif = rt->rt_ifp) != in6p->in6p_last_outifp) {
 597                                 in6p->in6p_last_outifp = outif;
 598
 599                                 so->so_pktheadroom = P2ROUNDUP(
 600                                     sizeof(struct udphdr) +
 601                                     hlen +
 602                                     ifnet_hdrlen(outif) +
 603                                     ifnet_mbuf_packetpreamblelen(outif),
 604                                     sizeof(u_int32_t));
 605                         }
 606                 } else {
 607                         ROUTE_RELEASE(&in6p->in6p_route);
 608                 }
 609
 610                 /*
 611                  * If output interface was cellular/expensive, and this
 612                  * socket is denied access to it, generate an event.
 613                  */
 614                 if (error != 0 && (ip6oa.ip6oa_retflags & IP6OARF_IFDENIED) &&
 615                     (INP_NO_CELLULAR(in6p) || INP_NO_EXPENSIVE(in6p)))
 616                         soevent(in6p->inp_socket, (SO_FILT_HINT_LOCKED|
 617                             SO_FILT_HINT_IFDENIED));
 618                 break;
 619         case AF_INET:
 620                 error = EAFNOSUPPORT;
 621                 goto release;
 622         }
 623         goto releaseopt;
 624
 625 release:
 626         if (m != NULL)
 627                 m_freem(m);
 628
 629 releaseopt:
 630         if (control != NULL) {
 631                 if (optp == &opt)
 632                         ip6_clearpktopts(optp, -1);
 633                 m_freem(control);
 634         }
 635 #if CONTENT_FILTER
 636         if (cfil_tag)
 637                 m_tag_free(cfil_tag);
 638 #endif
 639         return (error);
 640 }