sys/netinet6/udp6_usrreq.c

   1 /*-
   2  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
   3  * Copyright (c) 2010-2011 Juniper Networks, Inc.
   4  * Copyright (c) 2014 Kevin Lo
   5  * All rights reserved.
   6  *
   7  * Portions of this software were developed by Robert N. M. Watson under
   8  * contract to Juniper Networks, Inc.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the project nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  *      $KAME: udp6_usrreq.c,v 1.27 2001/05/21 05:45:10 jinmei Exp $
  35  *      $KAME: udp6_output.c,v 1.31 2001/05/21 16:39:15 jinmei Exp $
  36  */
  37
  38 /*-
  39  * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
  40  *      The Regents of the University of California.
  41  * All rights reserved.
  42  *
  43  * Redistribution and use in source and binary forms, with or without
  44  * modification, are permitted provided that the following conditions
  45  * are met:
  46  * 1. Redistributions of source code must retain the above copyright
  47  *    notice, this list of conditions and the following disclaimer.
  48  * 2. Redistributions in binary form must reproduce the above copyright
  49  *    notice, this list of conditions and the following disclaimer in the
  50  *    documentation and/or other materials provided with the distribution.
  51  * 4. Neither the name of the University nor the names of its contributors
  52  *    may be used to endorse or promote products derived from this software
  53  *    without specific prior written permission.
  54  *
  55  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  56  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  57  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  58  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  59  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  60  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  61  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  62  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  63  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  64  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  65  * SUCH DAMAGE.
  66  *
  67  *      @(#)udp_usrreq.c        8.6 (Berkeley) 5/23/95
  68  */
  69
  70 #include <sys/cdefs.h>
  71 __FBSDID("$FreeBSD$");
  72
  73 #include "opt_inet.h"
  74 #include "opt_inet6.h"
  75 #include "opt_ipfw.h"
  76 #include "opt_ipsec.h"
  77 #include "opt_kdtrace.h"
  78
  79 #include <sys/param.h>
  80 #include <sys/jail.h>
  81 #include <sys/kernel.h>
  82 #include <sys/lock.h>
  83 #include <sys/mbuf.h>
  84 #include <sys/priv.h>
  85 #include <sys/proc.h>
  86 #include <sys/protosw.h>
  87 #include <sys/sdt.h>
  88 #include <sys/signalvar.h>
  89 #include <sys/socket.h>
  90 #include <sys/socketvar.h>
  91 #include <sys/sx.h>
  92 #include <sys/sysctl.h>
  93 #include <sys/syslog.h>
  94 #include <sys/systm.h>
  95
  96 #include <net/if.h>
  97 #include <net/if_types.h>
  98 #include <net/route.h>
  99
 100 #include <netinet/in.h>
 101 #include <netinet/in_kdtrace.h>
 102 #include <netinet/in_pcb.h>
 103 #include <netinet/in_systm.h>
 104 #include <netinet/in_var.h>
 105 #include <netinet/ip.h>
 106 #include <netinet/ip_icmp.h>
 107 #include <netinet/ip6.h>
 108 #include <netinet/icmp_var.h>
 109 #include <netinet/icmp6.h>
 110 #include <netinet/ip_var.h>
 111 #include <netinet/udp.h>
 112 #include <netinet/udp_var.h>
 113 #include <netinet/udplite.h>
 114
 115 #include <netinet6/ip6protosw.h>
 116 #include <netinet6/ip6_var.h>
 117 #include <netinet6/in6_pcb.h>
 118 #include <netinet6/udp6_var.h>
 119 #include <netinet6/scope6_var.h>
 120
 121 #ifdef IPSEC
 122 #include <netipsec/ipsec.h>
 123 #include <netipsec/ipsec6.h>
 124 #endif /* IPSEC */
 125
 126 #include <security/mac/mac_framework.h>
 127
 128 /*
 129  * UDP protocol implementation.
 130  * Per RFC 768, August, 1980.
 131  */
 132
 133 extern struct protosw   inetsw[];
 134 static void             udp6_detach(struct socket *so);
 135
 136 static void
 137 udp6_append(struct inpcb *inp, struct mbuf *n, int off,
 138     struct sockaddr_in6 *fromsa)
 139 {
 140         struct socket *so;
 141         struct mbuf *opts;
 142
 143         INP_LOCK_ASSERT(inp);
 144
 145 #ifdef IPSEC
 146         /* Check AH/ESP integrity. */
 147         if (ipsec6_in_reject(n, inp)) {
 148                 m_freem(n);
 149                 IPSEC6STAT_INC(ips_in_polvio);
 150                 return;
 151         }
 152 #endif /* IPSEC */
 153 #ifdef MAC
 154         if (mac_inpcb_check_deliver(inp, n) != 0) {
 155                 m_freem(n);
 156                 return;
 157         }
 158 #endif
 159         opts = NULL;
 160         if (inp->inp_flags & INP_CONTROLOPTS ||
 161             inp->inp_socket->so_options & SO_TIMESTAMP)
 162                 ip6_savecontrol(inp, n, &opts);
 163         m_adj(n, off + sizeof(struct udphdr));
 164
 165         so = inp->inp_socket;
 166         SOCKBUF_LOCK(&so->so_rcv);
 167         if (sbappendaddr_locked(&so->so_rcv, (struct sockaddr *)fromsa, n,
 168             opts) == 0) {
 169                 SOCKBUF_UNLOCK(&so->so_rcv);
 170                 m_freem(n);
 171                 if (opts)
 172                         m_freem(opts);
 173                 UDPSTAT_INC(udps_fullsock);
 174         } else
 175                 sorwakeup_locked(so);
 176 }
 177
 178 int
 179 udp6_input(struct mbuf **mp, int *offp, int proto)
 180 {
 181         struct mbuf *m = *mp;
 182         struct ifnet *ifp;
 183         struct ip6_hdr *ip6;
 184         struct udphdr *uh;
 185         struct inpcb *inp;
 186         struct inpcbinfo *pcbinfo;
 187         struct udpcb *up;
 188         int off = *offp;
 189         int cscov_partial;
 190         int plen, ulen;
 191         struct sockaddr_in6 fromsa;
 192         struct m_tag *fwd_tag;
 193         uint16_t uh_sum;
 194         uint8_t nxt;
 195
 196         ifp = m->m_pkthdr.rcvif;
 197         ip6 = mtod(m, struct ip6_hdr *);
 198
 199         if (faithprefix_p != NULL && (*faithprefix_p)(&ip6->ip6_dst)) {
 200                 /* XXX send icmp6 host/port unreach? */
 201                 m_freem(m);
 202                 return (IPPROTO_DONE);
 203         }
 204
 205 #ifndef PULLDOWN_TEST
 206         IP6_EXTHDR_CHECK(m, off, sizeof(struct udphdr), IPPROTO_DONE);
 207         ip6 = mtod(m, struct ip6_hdr *);
 208         uh = (struct udphdr *)((caddr_t)ip6 + off);
 209 #else
 210         IP6_EXTHDR_GET(uh, struct udphdr *, m, off, sizeof(*uh));
 211         if (!uh)
 212                 return (IPPROTO_DONE);
 213 #endif
 214
 215         UDPSTAT_INC(udps_ipackets);
 216
 217         /*
 218          * Destination port of 0 is illegal, based on RFC768.
 219          */
 220         if (uh->uh_dport == 0)
 221                 goto badunlocked;
 222
 223         plen = ntohs(ip6->ip6_plen) - off + sizeof(*ip6);
 224         ulen = ntohs((u_short)uh->uh_ulen);
 225
 226         nxt = ip6->ip6_nxt;
 227         cscov_partial = (nxt == IPPROTO_UDPLITE) ? 1 : 0;
 228         if (nxt == IPPROTO_UDPLITE && ulen == 0) {
 229                 /* Zero means checksum over the complete packet. */
 230                 ulen = plen;
 231                 cscov_partial = 0;
 232         }
 233         if (plen != ulen) {
 234                 UDPSTAT_INC(udps_badlen);
 235                 goto badunlocked;
 236         }
 237
 238         /*
 239          * Checksum extended UDP header and data.
 240          */
 241         if (uh->uh_sum == 0) {
 242                 if (ulen > plen || ulen < sizeof(struct udphdr)) {
 243                         UDPSTAT_INC(udps_nosum);
 244                         goto badunlocked;
 245                 }
 246         }
 247
 248         if ((m->m_pkthdr.csum_flags & CSUM_DATA_VALID_IPV6) &&
 249             !cscov_partial) {
 250                 if (m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR)
 251                         uh_sum = m->m_pkthdr.csum_data;
 252                 else
 253                         uh_sum = in6_cksum_pseudo(ip6, ulen, nxt,
 254                             m->m_pkthdr.csum_data);
 255                 uh_sum ^= 0xffff;
 256         } else
 257                 uh_sum = in6_cksum(m, nxt, off, ulen);
 258
 259         if (uh_sum != 0) {
 260                 UDPSTAT_INC(udps_badsum);
 261                 goto badunlocked;
 262         }
 263
 264         /*
 265          * Construct sockaddr format source address.
 266          */
 267         init_sin6(&fromsa, m);
 268         fromsa.sin6_port = uh->uh_sport;
 269
 270         pcbinfo = get_inpcbinfo(nxt);
 271         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
 272                 struct inpcb *last;
 273                 struct inpcbhead *pcblist;
 274                 struct ip6_moptions *imo;
 275
 276                 INP_INFO_RLOCK(pcbinfo);
 277                 /*
 278                  * In the event that laddr should be set to the link-local
 279                  * address (this happens in RIPng), the multicast address
 280                  * specified in the received packet will not match laddr.  To
 281                  * handle this situation, matching is relaxed if the
 282                  * receiving interface is the same as one specified in the
 283                  * socket and if the destination multicast address matches
 284                  * one of the multicast groups specified in the socket.
 285                  */
 286
 287                 /*
 288                  * KAME note: traditionally we dropped udpiphdr from mbuf
 289                  * here.  We need udphdr for IPsec processing so we do that
 290                  * later.
 291                  */
 292                 pcblist = get_pcblist(nxt);
 293                 last = NULL;
 294                 LIST_FOREACH(inp, pcblist, inp_list) {
 295                         if ((inp->inp_vflag & INP_IPV6) == 0)
 296                                 continue;
 297                         if (inp->inp_lport != uh->uh_dport)
 298                                 continue;
 299                         if (inp->inp_fport != 0 &&
 300                             inp->inp_fport != uh->uh_sport)
 301                                 continue;
 302                         if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr)) {
 303                                 if (!IN6_ARE_ADDR_EQUAL(&inp->in6p_laddr,
 304                                                         &ip6->ip6_dst))
 305                                         continue;
 306                         }
 307                         if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
 308                                 if (!IN6_ARE_ADDR_EQUAL(&inp->in6p_faddr,
 309                                                         &ip6->ip6_src) ||
 310                                     inp->inp_fport != uh->uh_sport)
 311                                         continue;
 312                         }
 313
 314                         /*
 315                          * XXXRW: Because we weren't holding either the inpcb
 316                          * or the hash lock when we checked for a match
 317                          * before, we should probably recheck now that the
 318                          * inpcb lock is (supposed to be) held.
 319                          */
 320
 321                         /*
 322                          * Handle socket delivery policy for any-source
 323                          * and source-specific multicast. [RFC3678]
 324                          */
 325                         imo = inp->in6p_moptions;
 326                         if (imo && IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
 327                                 struct sockaddr_in6      mcaddr;
 328                                 int                      blocked;
 329
 330                                 INP_RLOCK(inp);
 331
 332                                 bzero(&mcaddr, sizeof(struct sockaddr_in6));
 333                                 mcaddr.sin6_len = sizeof(struct sockaddr_in6);
 334                                 mcaddr.sin6_family = AF_INET6;
 335                                 mcaddr.sin6_addr = ip6->ip6_dst;
 336
 337                                 blocked = im6o_mc_filter(imo, ifp,
 338                                         (struct sockaddr *)&mcaddr,
 339                                         (struct sockaddr *)&fromsa);
 340                                 if (blocked != MCAST_PASS) {
 341                                         if (blocked == MCAST_NOTGMEMBER)
 342                                                 IP6STAT_INC(ip6s_notmember);
 343                                         if (blocked == MCAST_NOTSMEMBER ||
 344                                             blocked == MCAST_MUTED)
 345                                                 UDPSTAT_INC(udps_filtermcast);
 346                                         INP_RUNLOCK(inp); /* XXX */
 347                                         continue;
 348                                 }
 349
 350                                 INP_RUNLOCK(inp);
 351                         }
 352                         if (last != NULL) {
 353                                 struct mbuf *n;
 354
 355                                 if ((n = m_copy(m, 0, M_COPYALL)) != NULL) {
 356                                         INP_RLOCK(last);
 357                                         up = intoudpcb(last);
 358                                         if (up->u_tun_func == NULL) {
 359                                                 udp6_append(last, n, off, &fromsa);
 360                                         } else {
 361                                                 /*
 362                                                  * Engage the tunneling
 363                                                  * protocol we will have to
 364                                                  * leave the info_lock up,
 365                                                  * since we are hunting
 366                                                  * through multiple UDP's.
 367                                                  *
 368                                                  */
 369                                                 (*up->u_tun_func)(n, off, last);
 370                                         }
 371                                         INP_RUNLOCK(last);
 372                                 }
 373                         }
 374                         last = inp;
 375                         /*
 376                          * Don't look for additional matches if this one does
 377                          * not have either the SO_REUSEPORT or SO_REUSEADDR
 378                          * socket options set.  This heuristic avoids
 379                          * searching through all pcbs in the common case of a
 380                          * non-shared port.  It assumes that an application
 381                          * will never clear these options after setting them.
 382                          */
 383                         if ((last->inp_socket->so_options &
 384                              (SO_REUSEPORT|SO_REUSEADDR)) == 0)
 385                                 break;
 386                 }
 387
 388                 if (last == NULL) {
 389                         /*
 390                          * No matching pcb found; discard datagram.  (No need
 391                          * to send an ICMP Port Unreachable for a broadcast
 392                          * or multicast datgram.)
 393                          */
 394                         UDPSTAT_INC(udps_noport);
 395                         UDPSTAT_INC(udps_noportmcast);
 396                         goto badheadlocked;
 397                 }
 398                 INP_RLOCK(last);
 399                 INP_INFO_RUNLOCK(pcbinfo);
 400                 up = intoudpcb(last);
 401                 UDP_PROBE(receive, NULL, last, ip6, last, uh);
 402                 if (up->u_tun_func == NULL) {
 403                         udp6_append(last, m, off, &fromsa);
 404                 } else {
 405                         /*
 406                          * Engage the tunneling protocol.
 407                          */
 408                         (*up->u_tun_func)(m, off, last);
 409                 }
 410                 INP_RUNLOCK(last);
 411                 return (IPPROTO_DONE);
 412         }
 413         /*
 414          * Locate pcb for datagram.
 415          */
 416
 417         /*
 418          * Grab info from PACKET_TAG_IPFORWARD tag prepended to the chain.
 419          */
 420         if ((m->m_flags & M_IP6_NEXTHOP) &&
 421             (fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL)) != NULL) {
 422                 struct sockaddr_in6 *next_hop6;
 423
 424                 next_hop6 = (struct sockaddr_in6 *)(fwd_tag + 1);
 425
 426                 /*
 427                  * Transparently forwarded. Pretend to be the destination.
 428                  * Already got one like this?
 429                  */
 430                 inp = in6_pcblookup_mbuf(pcbinfo, &ip6->ip6_src,
 431                     uh->uh_sport, &ip6->ip6_dst, uh->uh_dport,
 432                     INPLOOKUP_RLOCKPCB, m->m_pkthdr.rcvif, m);
 433                 if (!inp) {
 434                         /*
 435                          * It's new.  Try to find the ambushing socket.
 436                          * Because we've rewritten the destination address,
 437                          * any hardware-generated hash is ignored.
 438                          */
 439                         inp = in6_pcblookup(pcbinfo, &ip6->ip6_src,
 440                             uh->uh_sport, &next_hop6->sin6_addr,
 441                             next_hop6->sin6_port ? htons(next_hop6->sin6_port) :
 442                             uh->uh_dport, INPLOOKUP_WILDCARD |
 443                             INPLOOKUP_RLOCKPCB, m->m_pkthdr.rcvif);
 444                 }
 445                 /* Remove the tag from the packet. We don't need it anymore. */
 446                 m_tag_delete(m, fwd_tag);
 447                 m->m_flags &= ~M_IP6_NEXTHOP;
 448         } else
 449                 inp = in6_pcblookup_mbuf(pcbinfo, &ip6->ip6_src,
 450                     uh->uh_sport, &ip6->ip6_dst, uh->uh_dport,
 451                     INPLOOKUP_WILDCARD | INPLOOKUP_RLOCKPCB,
 452                     m->m_pkthdr.rcvif, m);
 453         if (inp == NULL) {
 454                 if (udp_log_in_vain) {
 455                         char ip6bufs[INET6_ADDRSTRLEN];
 456                         char ip6bufd[INET6_ADDRSTRLEN];
 457
 458                         log(LOG_INFO,
 459                             "Connection attempt to UDP [%s]:%d from [%s]:%d\n",
 460                             ip6_sprintf(ip6bufd, &ip6->ip6_dst),
 461                             ntohs(uh->uh_dport),
 462                             ip6_sprintf(ip6bufs, &ip6->ip6_src),
 463                             ntohs(uh->uh_sport));
 464                 }
 465                 UDPSTAT_INC(udps_noport);
 466                 if (m->m_flags & M_MCAST) {
 467                         printf("UDP6: M_MCAST is set in a unicast packet.\n");
 468                         UDPSTAT_INC(udps_noportmcast);
 469                         goto badunlocked;
 470                 }
 471                 if (V_udp_blackhole)
 472                         goto badunlocked;
 473                 if (badport_bandlim(BANDLIM_ICMP6_UNREACH) < 0)
 474                         goto badunlocked;
 475                 icmp6_error(m, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOPORT, 0);
 476                 return (IPPROTO_DONE);
 477         }
 478         INP_RLOCK_ASSERT(inp);
 479         up = intoudpcb(inp);
 480         if (cscov_partial) {
 481                 if (up->u_rxcslen > ulen) {
 482                         INP_RUNLOCK(inp);
 483                         m_freem(m);
 484                         return (IPPROTO_DONE);
 485                 }
 486         }
 487         UDP_PROBE(receive, NULL, inp, ip6, inp, uh);
 488         if (up->u_tun_func == NULL) {
 489                 udp6_append(inp, m, off, &fromsa);
 490         } else {
 491                 /*
 492                  * Engage the tunneling protocol.
 493                  */
 494
 495                 (*up->u_tun_func)(m, off, inp);
 496         }
 497         INP_RUNLOCK(inp);
 498         return (IPPROTO_DONE);
 499
 500 badheadlocked:
 501         INP_INFO_RUNLOCK(pcbinfo);
 502 badunlocked:
 503         if (m)
 504                 m_freem(m);
 505         return (IPPROTO_DONE);
 506 }
 507
 508 static void
 509 udp6_common_ctlinput(int cmd, struct sockaddr *sa, void *d,
 510     struct inpcbinfo *pcbinfo)
 511 {
 512         struct udphdr uh;
 513         struct ip6_hdr *ip6;
 514         struct mbuf *m;
 515         int off = 0;
 516         struct ip6ctlparam *ip6cp = NULL;
 517         const struct sockaddr_in6 *sa6_src = NULL;
 518         void *cmdarg;
 519         struct inpcb *(*notify)(struct inpcb *, int) = udp_notify;
 520         struct udp_portonly {
 521                 u_int16_t uh_sport;
 522                 u_int16_t uh_dport;
 523         } *uhp;
 524
 525         if (sa->sa_family != AF_INET6 ||
 526             sa->sa_len != sizeof(struct sockaddr_in6))
 527                 return;
 528
 529         if ((unsigned)cmd >= PRC_NCMDS)
 530                 return;
 531         if (PRC_IS_REDIRECT(cmd))
 532                 notify = in6_rtchange, d = NULL;
 533         else if (cmd == PRC_HOSTDEAD)
 534                 d = NULL;
 535         else if (inet6ctlerrmap[cmd] == 0)
 536                 return;
 537
 538         /* if the parameter is from icmp6, decode it. */
 539         if (d != NULL) {
 540                 ip6cp = (struct ip6ctlparam *)d;
 541                 m = ip6cp->ip6c_m;
 542                 ip6 = ip6cp->ip6c_ip6;
 543                 off = ip6cp->ip6c_off;
 544                 cmdarg = ip6cp->ip6c_cmdarg;
 545                 sa6_src = ip6cp->ip6c_src;
 546         } else {
 547                 m = NULL;
 548                 ip6 = NULL;
 549                 cmdarg = NULL;
 550                 sa6_src = &sa6_any;
 551         }
 552
 553         if (ip6) {
 554                 /*
 555                  * XXX: We assume that when IPV6 is non NULL,
 556                  * M and OFF are valid.
 557                  */
 558
 559                 /* Check if we can safely examine src and dst ports. */
 560                 if (m->m_pkthdr.len < off + sizeof(*uhp))
 561                         return;
 562
 563                 bzero(&uh, sizeof(uh));
 564                 m_copydata(m, off, sizeof(*uhp), (caddr_t)&uh);
 565
 566                 (void)in6_pcbnotify(pcbinfo, sa, uh.uh_dport,
 567                     (struct sockaddr *)ip6cp->ip6c_src, uh.uh_sport, cmd,
 568                     cmdarg, notify);
 569         } else
 570                 (void)in6_pcbnotify(pcbinfo, sa, 0,
 571                     (const struct sockaddr *)sa6_src, 0, cmd, cmdarg, notify);
 572 }
 573
 574 void
 575 udp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
 576 {
 577
 578         return (udp6_common_ctlinput(cmd, sa, d, &V_udbinfo));
 579 }
 580
 581 void
 582 udplite6_ctlinput(int cmd, struct sockaddr *sa, void *d)
 583 {
 584
 585         return (udp6_common_ctlinput(cmd, sa, d, &V_ulitecbinfo));
 586 }
 587
 588 static int
 589 udp6_getcred(SYSCTL_HANDLER_ARGS)
 590 {
 591         struct xucred xuc;
 592         struct sockaddr_in6 addrs[2];
 593         struct inpcb *inp;
 594         int error;
 595
 596         error = priv_check(req->td, PRIV_NETINET_GETCRED);
 597         if (error)
 598                 return (error);
 599
 600         if (req->newlen != sizeof(addrs))
 601                 return (EINVAL);
 602         if (req->oldlen != sizeof(struct xucred))
 603                 return (EINVAL);
 604         error = SYSCTL_IN(req, addrs, sizeof(addrs));
 605         if (error)
 606                 return (error);
 607         if ((error = sa6_embedscope(&addrs[0], V_ip6_use_defzone)) != 0 ||
 608             (error = sa6_embedscope(&addrs[1], V_ip6_use_defzone)) != 0) {
 609                 return (error);
 610         }
 611         inp = in6_pcblookup(&V_udbinfo, &addrs[1].sin6_addr,
 612             addrs[1].sin6_port, &addrs[0].sin6_addr, addrs[0].sin6_port,
 613             INPLOOKUP_WILDCARD | INPLOOKUP_RLOCKPCB, NULL);
 614         if (inp != NULL) {
 615                 INP_RLOCK_ASSERT(inp);
 616                 if (inp->inp_socket == NULL)
 617                         error = ENOENT;
 618                 if (error == 0)
 619                         error = cr_canseesocket(req->td->td_ucred,
 620                             inp->inp_socket);
 621                 if (error == 0)
 622                         cru2x(inp->inp_cred, &xuc);
 623                 INP_RUNLOCK(inp);
 624         } else
 625                 error = ENOENT;
 626         if (error == 0)
 627                 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
 628         return (error);
 629 }
 630
 631 SYSCTL_PROC(_net_inet6_udp6, OID_AUTO, getcred, CTLTYPE_OPAQUE|CTLFLAG_RW, 0,
 632     0, udp6_getcred, "S,xucred", "Get the xucred of a UDP6 connection");
 633
 634 static int
 635 udp6_output(struct inpcb *inp, struct mbuf *m, struct sockaddr *addr6,
 636     struct mbuf *control, struct thread *td)
 637 {
 638         u_int32_t ulen = m->m_pkthdr.len;
 639         u_int32_t plen = sizeof(struct udphdr) + ulen;
 640         struct ip6_hdr *ip6;
 641         struct udphdr *udp6;
 642         struct in6_addr *laddr, *faddr, in6a;
 643         struct sockaddr_in6 *sin6 = NULL;
 644         struct ifnet *oifp = NULL;
 645         int cscov_partial = 0;
 646         int scope_ambiguous = 0;
 647         u_short fport;
 648         int error = 0;
 649         uint8_t nxt;
 650         uint16_t cscov = 0;
 651         struct ip6_pktopts *optp, opt;
 652         int af = AF_INET6, hlen = sizeof(struct ip6_hdr);
 653         int flags;
 654         struct sockaddr_in6 tmp;
 655
 656         INP_WLOCK_ASSERT(inp);
 657         INP_HASH_WLOCK_ASSERT(inp->inp_pcbinfo);
 658
 659         if (addr6) {
 660                 /* addr6 has been validated in udp6_send(). */
 661                 sin6 = (struct sockaddr_in6 *)addr6;
 662
 663                 /* protect *sin6 from overwrites */
 664                 tmp = *sin6;
 665                 sin6 = &tmp;
 666
 667                 /*
 668                  * Application should provide a proper zone ID or the use of
 669                  * default zone IDs should be enabled.  Unfortunately, some
 670                  * applications do not behave as it should, so we need a
 671                  * workaround.  Even if an appropriate ID is not determined,
 672                  * we'll see if we can determine the outgoing interface.  If we
 673                  * can, determine the zone ID based on the interface below.
 674                  */
 675                 if (sin6->sin6_scope_id == 0 && !V_ip6_use_defzone)
 676                         scope_ambiguous = 1;
 677                 if ((error = sa6_embedscope(sin6, V_ip6_use_defzone)) != 0)
 678                         return (error);
 679         }
 680
 681         if (control) {
 682                 if ((error = ip6_setpktopts(control, &opt,
 683                     inp->in6p_outputopts, td->td_ucred, IPPROTO_UDP)) != 0)
 684                         goto release;
 685                 optp = &opt;
 686         } else
 687                 optp = inp->in6p_outputopts;
 688
 689         if (sin6) {
 690                 faddr = &sin6->sin6_addr;
 691
 692                 /*
 693                  * Since we saw no essential reason for calling in_pcbconnect,
 694                  * we get rid of such kind of logic, and call in6_selectsrc
 695                  * and in6_pcbsetport in order to fill in the local address
 696                  * and the local port.
 697                  */
 698                 if (sin6->sin6_port == 0) {
 699                         error = EADDRNOTAVAIL;
 700                         goto release;
 701                 }
 702
 703                 if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
 704                         /* how about ::ffff:0.0.0.0 case? */
 705                         error = EISCONN;
 706                         goto release;
 707                 }
 708
 709                 fport = sin6->sin6_port; /* allow 0 port */
 710
 711                 if (IN6_IS_ADDR_V4MAPPED(faddr)) {
 712                         if ((inp->inp_flags & IN6P_IPV6_V6ONLY)) {
 713                                 /*
 714                                  * I believe we should explicitly discard the
 715                                  * packet when mapped addresses are disabled,
 716                                  * rather than send the packet as an IPv6 one.
 717                                  * If we chose the latter approach, the packet
 718                                  * might be sent out on the wire based on the
 719                                  * default route, the situation which we'd
 720                                  * probably want to avoid.
 721                                  * (20010421 jinmei@kame.net)
 722                                  */
 723                                 error = EINVAL;
 724                                 goto release;
 725                         }
 726                         if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr) &&
 727                             !IN6_IS_ADDR_V4MAPPED(&inp->in6p_laddr)) {
 728                                 /*
 729                                  * when remote addr is an IPv4-mapped address,
 730                                  * local addr should not be an IPv6 address,
 731                                  * since you cannot determine how to map IPv6
 732                                  * source address to IPv4.
 733                                  */
 734                                 error = EINVAL;
 735                                 goto release;
 736                         }
 737
 738                         af = AF_INET;
 739                 }
 740
 741                 if (!IN6_IS_ADDR_V4MAPPED(faddr)) {
 742                         error = in6_selectsrc(sin6, optp, inp, NULL,
 743                             td->td_ucred, &oifp, &in6a);
 744                         if (error)
 745                                 goto release;
 746                         if (oifp && scope_ambiguous &&
 747                             (error = in6_setscope(&sin6->sin6_addr,
 748                             oifp, NULL))) {
 749                                 goto release;
 750                         }
 751                         laddr = &in6a;
 752                 } else
 753                         laddr = &inp->in6p_laddr;       /* XXX */
 754                 if (laddr == NULL) {
 755                         if (error == 0)
 756                                 error = EADDRNOTAVAIL;
 757                         goto release;
 758                 }
 759                 if (inp->inp_lport == 0 &&
 760                     (error = in6_pcbsetport(laddr, inp, td->td_ucred)) != 0) {
 761                         /* Undo an address bind that may have occurred. */
 762                         inp->in6p_laddr = in6addr_any;
 763                         goto release;
 764                 }
 765         } else {
 766                 if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
 767                         error = ENOTCONN;
 768                         goto release;
 769                 }
 770                 if (IN6_IS_ADDR_V4MAPPED(&inp->in6p_faddr)) {
 771                         if ((inp->inp_flags & IN6P_IPV6_V6ONLY)) {
 772                                 /*
 773                                  * XXX: this case would happen when the
 774                                  * application sets the V6ONLY flag after
 775                                  * connecting the foreign address.
 776                                  * Such applications should be fixed,
 777                                  * so we bark here.
 778                                  */
 779                                 log(LOG_INFO, "udp6_output: IPV6_V6ONLY "
 780                                     "option was set for a connected socket\n");
 781                                 error = EINVAL;
 782                                 goto release;
 783                         } else
 784                                 af = AF_INET;
 785                 }
 786                 laddr = &inp->in6p_laddr;
 787                 faddr = &inp->in6p_faddr;
 788                 fport = inp->inp_fport;
 789         }
 790
 791         if (af == AF_INET)
 792                 hlen = sizeof(struct ip);
 793
 794         /*
 795          * Calculate data length and get a mbuf
 796          * for UDP and IP6 headers.
 797          */
 798         M_PREPEND(m, hlen + sizeof(struct udphdr), M_NOWAIT);
 799         if (m == 0) {
 800                 error = ENOBUFS;
 801                 goto release;
 802         }
 803
 804         /*
 805          * Stuff checksum and output datagram.
 806          */
 807         nxt = (inp->inp_socket->so_proto->pr_protocol == IPPROTO_UDP) ?
 808             IPPROTO_UDP : IPPROTO_UDPLITE;
 809         udp6 = (struct udphdr *)(mtod(m, caddr_t) + hlen);
 810         udp6->uh_sport = inp->inp_lport; /* lport is always set in the PCB */
 811         udp6->uh_dport = fport;
 812         if (nxt == IPPROTO_UDPLITE) {
 813                 struct udpcb *up;
 814
 815                 up = intoudpcb(inp);
 816                 cscov = up->u_txcslen;
 817                 if (cscov >= plen)
 818                         cscov = 0;
 819                 udp6->uh_ulen = htons(cscov);
 820                 /*
 821                  * For UDP-Lite, checksum coverage length of zero means
 822                  * the entire UDPLite packet is covered by the checksum.
 823                  */
 824                 cscov_partial = (cscov == 0) ? 0 : 1;
 825         } else if (plen <= 0xffff)
 826                 udp6->uh_ulen = htons((u_short)plen);
 827         else
 828                 udp6->uh_ulen = 0;
 829         udp6->uh_sum = 0;
 830
 831         switch (af) {
 832         case AF_INET6:
 833                 ip6 = mtod(m, struct ip6_hdr *);
 834                 ip6->ip6_flow   = inp->inp_flow & IPV6_FLOWINFO_MASK;
 835                 ip6->ip6_vfc    &= ~IPV6_VERSION_MASK;
 836                 ip6->ip6_vfc    |= IPV6_VERSION;
 837                 ip6->ip6_plen   = htons((u_short)plen);
 838                 ip6->ip6_nxt    = nxt;
 839                 ip6->ip6_hlim   = in6_selecthlim(inp, NULL);
 840                 ip6->ip6_src    = *laddr;
 841                 ip6->ip6_dst    = *faddr;
 842
 843                 if (cscov_partial) {
 844                         if ((udp6->uh_sum = in6_cksum(m, 0,
 845                             sizeof(struct ip6_hdr), cscov)) == 0)
 846                                 udp6->uh_sum = 0xffff;
 847                 } else {
 848                         udp6->uh_sum = in6_cksum_pseudo(ip6, plen, nxt, 0);
 849                         m->m_pkthdr.csum_flags = CSUM_UDP_IPV6;
 850                         m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
 851                 }
 852
 853                 flags = 0;
 854
 855                 UDP_PROBE(send, NULL, inp, ip6, inp, udp6);
 856                 UDPSTAT_INC(udps_opackets);
 857                 error = ip6_output(m, optp, NULL, flags, inp->in6p_moptions,
 858                     NULL, inp);
 859                 break;
 860         case AF_INET:
 861                 error = EAFNOSUPPORT;
 862                 goto release;
 863         }
 864         goto releaseopt;
 865
 866 release:
 867         m_freem(m);
 868
 869 releaseopt:
 870         if (control) {
 871                 ip6_clearpktopts(&opt, -1);
 872                 m_freem(control);
 873         }
 874         return (error);
 875 }
 876
 877 static void
 878 udp6_abort(struct socket *so)
 879 {
 880         struct inpcb *inp;
 881         struct inpcbinfo *pcbinfo;
 882
 883         pcbinfo = get_inpcbinfo(so->so_proto->pr_protocol);
 884         inp = sotoinpcb(so);
 885         KASSERT(inp != NULL, ("udp6_abort: inp == NULL"));
 886
 887 #ifdef INET
 888         if (inp->inp_vflag & INP_IPV4) {
 889                 struct pr_usrreqs *pru;
 890
 891                 pru = inetsw[ip_protox[IPPROTO_UDP]].pr_usrreqs;
 892                 (*pru->pru_abort)(so);
 893                 return;
 894         }
 895 #endif
 896
 897         INP_WLOCK(inp);
 898         if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
 899                 INP_HASH_WLOCK(pcbinfo);
 900                 in6_pcbdisconnect(inp);
 901                 inp->in6p_laddr = in6addr_any;
 902                 INP_HASH_WUNLOCK(pcbinfo);
 903                 soisdisconnected(so);
 904         }
 905         INP_WUNLOCK(inp);
 906 }
 907
 908 static int
 909 udp6_attach(struct socket *so, int proto, struct thread *td)
 910 {
 911         struct inpcb *inp;
 912         struct inpcbinfo *pcbinfo;
 913         int error;
 914
 915         pcbinfo = get_inpcbinfo(so->so_proto->pr_protocol);
 916         inp = sotoinpcb(so);
 917         KASSERT(inp == NULL, ("udp6_attach: inp != NULL"));
 918
 919         if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
 920                 error = soreserve(so, udp_sendspace, udp_recvspace);
 921                 if (error)
 922                         return (error);
 923         }
 924         INP_INFO_WLOCK(pcbinfo);
 925         error = in_pcballoc(so, pcbinfo);
 926         if (error) {
 927                 INP_INFO_WUNLOCK(pcbinfo);
 928                 return (error);
 929         }
 930         inp = (struct inpcb *)so->so_pcb;
 931         inp->inp_vflag |= INP_IPV6;
 932         if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0)
 933                 inp->inp_vflag |= INP_IPV4;
 934         inp->in6p_hops = -1;    /* use kernel default */
 935         inp->in6p_cksum = -1;   /* just to be sure */
 936         /*
 937          * XXX: ugly!!
 938          * IPv4 TTL initialization is necessary for an IPv6 socket as well,
 939          * because the socket may be bound to an IPv6 wildcard address,
 940          * which may match an IPv4-mapped IPv6 address.
 941          */
 942         inp->inp_ip_ttl = V_ip_defttl;
 943
 944         error = udp_newudpcb(inp);
 945         if (error) {
 946                 in_pcbdetach(inp);
 947                 in_pcbfree(inp);
 948                 INP_INFO_WUNLOCK(pcbinfo);
 949                 return (error);
 950         }
 951         INP_WUNLOCK(inp);
 952         INP_INFO_WUNLOCK(pcbinfo);
 953         return (0);
 954 }
 955
 956 static int
 957 udp6_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
 958 {
 959         struct inpcb *inp;
 960         struct inpcbinfo *pcbinfo;
 961         int error;
 962
 963         pcbinfo = get_inpcbinfo(so->so_proto->pr_protocol);
 964         inp = sotoinpcb(so);
 965         KASSERT(inp != NULL, ("udp6_bind: inp == NULL"));
 966
 967         INP_WLOCK(inp);
 968         INP_HASH_WLOCK(pcbinfo);
 969         inp->inp_vflag &= ~INP_IPV4;
 970         inp->inp_vflag |= INP_IPV6;
 971         if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0) {
 972                 struct sockaddr_in6 *sin6_p;
 973
 974                 sin6_p = (struct sockaddr_in6 *)nam;
 975
 976                 if (IN6_IS_ADDR_UNSPECIFIED(&sin6_p->sin6_addr))
 977                         inp->inp_vflag |= INP_IPV4;
 978 #ifdef INET
 979                 else if (IN6_IS_ADDR_V4MAPPED(&sin6_p->sin6_addr)) {
 980                         struct sockaddr_in sin;
 981
 982                         in6_sin6_2_sin(&sin, sin6_p);
 983                         inp->inp_vflag |= INP_IPV4;
 984                         inp->inp_vflag &= ~INP_IPV6;
 985                         error = in_pcbbind(inp, (struct sockaddr *)&sin,
 986                             td->td_ucred);
 987                         goto out;
 988                 }
 989 #endif
 990         }
 991
 992         error = in6_pcbbind(inp, nam, td->td_ucred);
 993 #ifdef INET
 994 out:
 995 #endif
 996         INP_HASH_WUNLOCK(pcbinfo);
 997         INP_WUNLOCK(inp);
 998         return (error);
 999 }
1000
1001 static void
1002 udp6_close(struct socket *so)
1003 {
1004         struct inpcb *inp;
1005         struct inpcbinfo *pcbinfo;
1006
1007         pcbinfo = get_inpcbinfo(so->so_proto->pr_protocol);
1008         inp = sotoinpcb(so);
1009         KASSERT(inp != NULL, ("udp6_close: inp == NULL"));
1010
1011 #ifdef INET
1012         if (inp->inp_vflag & INP_IPV4) {
1013                 struct pr_usrreqs *pru;
1014
1015                 pru = inetsw[ip_protox[IPPROTO_UDP]].pr_usrreqs;
1016                 (*pru->pru_disconnect)(so);
1017                 return;
1018         }
1019 #endif
1020         INP_WLOCK(inp);
1021         if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
1022                 INP_HASH_WLOCK(pcbinfo);
1023                 in6_pcbdisconnect(inp);
1024                 inp->in6p_laddr = in6addr_any;
1025                 INP_HASH_WUNLOCK(pcbinfo);
1026                 soisdisconnected(so);
1027         }
1028         INP_WUNLOCK(inp);
1029 }
1030
1031 static int
1032 udp6_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
1033 {
1034         struct inpcb *inp;
1035         struct inpcbinfo *pcbinfo;
1036         struct sockaddr_in6 *sin6;
1037         int error;
1038
1039         pcbinfo = get_inpcbinfo(so->so_proto->pr_protocol);
1040         inp = sotoinpcb(so);
1041         sin6 = (struct sockaddr_in6 *)nam;
1042         KASSERT(inp != NULL, ("udp6_connect: inp == NULL"));
1043
1044         /*
1045          * XXXRW: Need to clarify locking of v4/v6 flags.
1046          */
1047         INP_WLOCK(inp);
1048 #ifdef INET
1049         if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) {
1050                 struct sockaddr_in sin;
1051
1052                 if ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0) {
1053                         error = EINVAL;
1054                         goto out;
1055                 }
1056                 if (inp->inp_faddr.s_addr != INADDR_ANY) {
1057                         error = EISCONN;
1058                         goto out;
1059                 }
1060                 in6_sin6_2_sin(&sin, sin6);
1061                 inp->inp_vflag |= INP_IPV4;
1062                 inp->inp_vflag &= ~INP_IPV6;
1063                 error = prison_remote_ip4(td->td_ucred, &sin.sin_addr);
1064                 if (error != 0)
1065                         goto out;
1066                 INP_HASH_WLOCK(pcbinfo);
1067                 error = in_pcbconnect(inp, (struct sockaddr *)&sin,
1068                     td->td_ucred);
1069                 INP_HASH_WUNLOCK(pcbinfo);
1070                 if (error == 0)
1071                         soisconnected(so);
1072                 goto out;
1073         }
1074 #endif
1075         if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
1076                 error = EISCONN;
1077                 goto out;
1078         }
1079         inp->inp_vflag &= ~INP_IPV4;
1080         inp->inp_vflag |= INP_IPV6;
1081         error = prison_remote_ip6(td->td_ucred, &sin6->sin6_addr);
1082         if (error != 0)
1083                 goto out;
1084         INP_HASH_WLOCK(pcbinfo);
1085         error = in6_pcbconnect(inp, nam, td->td_ucred);
1086         INP_HASH_WUNLOCK(pcbinfo);
1087         if (error == 0)
1088                 soisconnected(so);
1089 out:
1090         INP_WUNLOCK(inp);
1091         return (error);
1092 }
1093
1094 static void
1095 udp6_detach(struct socket *so)
1096 {
1097         struct inpcb *inp;
1098         struct inpcbinfo *pcbinfo;
1099         struct udpcb *up;
1100
1101         pcbinfo = get_inpcbinfo(so->so_proto->pr_protocol);
1102         inp = sotoinpcb(so);
1103         KASSERT(inp != NULL, ("udp6_detach: inp == NULL"));
1104
1105         INP_INFO_WLOCK(pcbinfo);
1106         INP_WLOCK(inp);
1107         up = intoudpcb(inp);
1108         KASSERT(up != NULL, ("%s: up == NULL", __func__));
1109         in_pcbdetach(inp);
1110         in_pcbfree(inp);
1111         INP_INFO_WUNLOCK(pcbinfo);
1112         udp_discardcb(up);
1113 }
1114
1115 static int
1116 udp6_disconnect(struct socket *so)
1117 {
1118         struct inpcb *inp;
1119         struct inpcbinfo *pcbinfo;
1120         int error;
1121
1122         pcbinfo = get_inpcbinfo(so->so_proto->pr_protocol);
1123         inp = sotoinpcb(so);
1124         KASSERT(inp != NULL, ("udp6_disconnect: inp == NULL"));
1125
1126 #ifdef INET
1127         if (inp->inp_vflag & INP_IPV4) {
1128                 struct pr_usrreqs *pru;
1129
1130                 pru = inetsw[ip_protox[IPPROTO_UDP]].pr_usrreqs;
1131                 (void)(*pru->pru_disconnect)(so);
1132                 return (0);
1133         }
1134 #endif
1135
1136         INP_WLOCK(inp);
1137
1138         if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
1139                 error = ENOTCONN;
1140                 goto out;
1141         }
1142
1143         INP_HASH_WLOCK(pcbinfo);
1144         in6_pcbdisconnect(inp);
1145         inp->in6p_laddr = in6addr_any;
1146         INP_HASH_WUNLOCK(pcbinfo);
1147         SOCK_LOCK(so);
1148         so->so_state &= ~SS_ISCONNECTED;                /* XXX */
1149         SOCK_UNLOCK(so);
1150 out:
1151         INP_WUNLOCK(inp);
1152         return (0);
1153 }
1154
1155 static int
1156 udp6_send(struct socket *so, int flags, struct mbuf *m,
1157     struct sockaddr *addr, struct mbuf *control, struct thread *td)
1158 {
1159         struct inpcb *inp;
1160         struct inpcbinfo *pcbinfo;
1161         int error = 0;
1162
1163         pcbinfo = get_inpcbinfo(so->so_proto->pr_protocol);
1164         inp = sotoinpcb(so);
1165         KASSERT(inp != NULL, ("udp6_send: inp == NULL"));
1166
1167         INP_WLOCK(inp);
1168         if (addr) {
1169                 if (addr->sa_len != sizeof(struct sockaddr_in6)) {
1170                         error = EINVAL;
1171                         goto bad;
1172                 }
1173                 if (addr->sa_family != AF_INET6) {
1174                         error = EAFNOSUPPORT;
1175                         goto bad;
1176                 }
1177         }
1178
1179 #ifdef INET
1180         if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0) {
1181                 int hasv4addr;
1182                 struct sockaddr_in6 *sin6 = 0;
1183
1184                 if (addr == 0)
1185                         hasv4addr = (inp->inp_vflag & INP_IPV4);
1186                 else {
1187                         sin6 = (struct sockaddr_in6 *)addr;
1188                         hasv4addr = IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)
1189                             ? 1 : 0;
1190                 }
1191                 if (hasv4addr) {
1192                         struct pr_usrreqs *pru;
1193
1194                         /*
1195                          * XXXRW: We release UDP-layer locks before calling
1196                          * udp_send() in order to avoid recursion.  However,
1197                          * this does mean there is a short window where inp's
1198                          * fields are unstable.  Could this lead to a
1199                          * potential race in which the factors causing us to
1200                          * select the UDPv4 output routine are invalidated?
1201                          */
1202                         INP_WUNLOCK(inp);
1203                         if (sin6)
1204                                 in6_sin6_2_sin_in_sock(addr);
1205                         pru = inetsw[ip_protox[IPPROTO_UDP]].pr_usrreqs;
1206                         /* addr will just be freed in sendit(). */
1207                         return ((*pru->pru_send)(so, flags, m, addr, control,
1208                             td));
1209                 }
1210         }
1211 #endif
1212 #ifdef MAC
1213         mac_inpcb_create_mbuf(inp, m);
1214 #endif
1215         INP_HASH_WLOCK(pcbinfo);
1216         error = udp6_output(inp, m, addr, control, td);
1217         INP_HASH_WUNLOCK(pcbinfo);
1218 #ifdef INET
1219 #endif
1220         INP_WUNLOCK(inp);
1221         return (error);
1222
1223 bad:
1224         INP_WUNLOCK(inp);
1225         m_freem(m);
1226         return (error);
1227 }
1228
1229 struct pr_usrreqs udp6_usrreqs = {
1230         .pru_abort =            udp6_abort,
1231         .pru_attach =           udp6_attach,
1232         .pru_bind =             udp6_bind,
1233         .pru_connect =          udp6_connect,
1234         .pru_control =          in6_control,
1235         .pru_detach =           udp6_detach,
1236         .pru_disconnect =       udp6_disconnect,
1237         .pru_peeraddr =         in6_mapped_peeraddr,
1238         .pru_send =             udp6_send,
1239         .pru_shutdown =         udp_shutdown,
1240         .pru_sockaddr =         in6_mapped_sockaddr,
1241         .pru_soreceive =        soreceive_dgram,
1242         .pru_sosend =           sosend_dgram,
1243         .pru_sosetlabel =       in_pcbsosetlabel,
1244         .pru_close =            udp6_close
1245 };