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 || ulen == plen)) {
 229                 /* Zero means checksum over the complete packet. */
 230                 if (ulen == 0)
 231                         ulen = plen;
 232                 cscov_partial = 0;
 233         }
 234         if (nxt == IPPROTO_UDP && plen != ulen) {
 235                 UDPSTAT_INC(udps_badlen);
 236                 goto badunlocked;
 237         }
 238
 239         /*
 240          * Checksum extended UDP header and data.
 241          */
 242         if (uh->uh_sum == 0) {
 243                 if (ulen > plen || ulen < sizeof(struct udphdr)) {
 244                         UDPSTAT_INC(udps_nosum);
 245                         goto badunlocked;
 246                 }
 247         }
 248
 249         if ((m->m_pkthdr.csum_flags & CSUM_DATA_VALID_IPV6) &&
 250             !cscov_partial) {
 251                 if (m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR)
 252                         uh_sum = m->m_pkthdr.csum_data;
 253                 else
 254                         uh_sum = in6_cksum_pseudo(ip6, ulen, nxt,
 255                             m->m_pkthdr.csum_data);
 256                 uh_sum ^= 0xffff;
 257         } else
 258                 uh_sum = in6_cksum(m, nxt, off, ulen);
 259
 260         if (uh_sum != 0) {
 261                 UDPSTAT_INC(udps_badsum);
 262                 goto badunlocked;
 263         }
 264
 265         /*
 266          * Construct sockaddr format source address.
 267          */
 268         init_sin6(&fromsa, m);
 269         fromsa.sin6_port = uh->uh_sport;
 270
 271         pcbinfo = get_inpcbinfo(nxt);
 272         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
 273                 struct inpcb *last;
 274                 struct inpcbhead *pcblist;
 275                 struct ip6_moptions *imo;
 276
 277                 INP_INFO_RLOCK(pcbinfo);
 278                 /*
 279                  * In the event that laddr should be set to the link-local
 280                  * address (this happens in RIPng), the multicast address
 281                  * specified in the received packet will not match laddr.  To
 282                  * handle this situation, matching is relaxed if the
 283                  * receiving interface is the same as one specified in the
 284                  * socket and if the destination multicast address matches
 285                  * one of the multicast groups specified in the socket.
 286                  */
 287
 288                 /*
 289                  * KAME note: traditionally we dropped udpiphdr from mbuf
 290                  * here.  We need udphdr for IPsec processing so we do that
 291                  * later.
 292                  */
 293                 pcblist = get_pcblist(nxt);
 294                 last = NULL;
 295                 LIST_FOREACH(inp, pcblist, inp_list) {
 296                         if ((inp->inp_vflag & INP_IPV6) == 0)
 297                                 continue;
 298                         if (inp->inp_lport != uh->uh_dport)
 299                                 continue;
 300                         if (inp->inp_fport != 0 &&
 301                             inp->inp_fport != uh->uh_sport)
 302                                 continue;
 303                         if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr)) {
 304                                 if (!IN6_ARE_ADDR_EQUAL(&inp->in6p_laddr,
 305                                                         &ip6->ip6_dst))
 306                                         continue;
 307                         }
 308                         if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
 309                                 if (!IN6_ARE_ADDR_EQUAL(&inp->in6p_faddr,
 310                                                         &ip6->ip6_src) ||
 311                                     inp->inp_fport != uh->uh_sport)
 312                                         continue;
 313                         }
 314
 315                         /*
 316                          * XXXRW: Because we weren't holding either the inpcb
 317                          * or the hash lock when we checked for a match
 318                          * before, we should probably recheck now that the
 319                          * inpcb lock is (supposed to be) held.
 320                          */
 321
 322                         /*
 323                          * Handle socket delivery policy for any-source
 324                          * and source-specific multicast. [RFC3678]
 325                          */
 326                         imo = inp->in6p_moptions;
 327                         if (imo && IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
 328                                 struct sockaddr_in6      mcaddr;
 329                                 int                      blocked;
 330
 331                                 INP_RLOCK(inp);
 332
 333                                 bzero(&mcaddr, sizeof(struct sockaddr_in6));
 334                                 mcaddr.sin6_len = sizeof(struct sockaddr_in6);
 335                                 mcaddr.sin6_family = AF_INET6;
 336                                 mcaddr.sin6_addr = ip6->ip6_dst;
 337
 338                                 blocked = im6o_mc_filter(imo, ifp,
 339                                         (struct sockaddr *)&mcaddr,
 340                                         (struct sockaddr *)&fromsa);
 341                                 if (blocked != MCAST_PASS) {
 342                                         if (blocked == MCAST_NOTGMEMBER)
 343                                                 IP6STAT_INC(ip6s_notmember);
 344                                         if (blocked == MCAST_NOTSMEMBER ||
 345                                             blocked == MCAST_MUTED)
 346                                                 UDPSTAT_INC(udps_filtermcast);
 347                                         INP_RUNLOCK(inp); /* XXX */
 348                                         continue;
 349                                 }
 350
 351                                 INP_RUNLOCK(inp);
 352                         }
 353                         if (last != NULL) {
 354                                 struct mbuf *n;
 355
 356                                 if ((n = m_copy(m, 0, M_COPYALL)) != NULL) {
 357                                         INP_RLOCK(last);
 358                                         up = intoudpcb(last);
 359                                         if (up->u_tun_func == NULL) {
 360                                                 udp6_append(last, n, off, &fromsa);
 361                                         } else {
 362                                                 /*
 363                                                  * Engage the tunneling
 364                                                  * protocol we will have to
 365                                                  * leave the info_lock up,
 366                                                  * since we are hunting
 367                                                  * through multiple UDP's.
 368                                                  *
 369                                                  */
 370                                                 (*up->u_tun_func)(n, off, last);
 371                                         }
 372                                         INP_RUNLOCK(last);
 373                                 }
 374                         }
 375                         last = inp;
 376                         /*
 377                          * Don't look for additional matches if this one does
 378                          * not have either the SO_REUSEPORT or SO_REUSEADDR
 379                          * socket options set.  This heuristic avoids
 380                          * searching through all pcbs in the common case of a
 381                          * non-shared port.  It assumes that an application
 382                          * will never clear these options after setting them.
 383                          */
 384                         if ((last->inp_socket->so_options &
 385                              (SO_REUSEPORT|SO_REUSEADDR)) == 0)
 386                                 break;
 387                 }
 388
 389                 if (last == NULL) {
 390                         /*
 391                          * No matching pcb found; discard datagram.  (No need
 392                          * to send an ICMP Port Unreachable for a broadcast
 393                          * or multicast datgram.)
 394                          */
 395                         UDPSTAT_INC(udps_noport);
 396                         UDPSTAT_INC(udps_noportmcast);
 397                         goto badheadlocked;
 398                 }
 399                 INP_RLOCK(last);
 400                 INP_INFO_RUNLOCK(pcbinfo);
 401                 up = intoudpcb(last);
 402                 UDP_PROBE(receive, NULL, last, ip6, last, uh);
 403                 if (up->u_tun_func == NULL) {
 404                         udp6_append(last, m, off, &fromsa);
 405                 } else {
 406                         /*
 407                          * Engage the tunneling protocol.
 408                          */
 409                         (*up->u_tun_func)(m, off, last);
 410                 }
 411                 INP_RUNLOCK(last);
 412                 return (IPPROTO_DONE);
 413         }
 414         /*
 415          * Locate pcb for datagram.
 416          */
 417
 418         /*
 419          * Grab info from PACKET_TAG_IPFORWARD tag prepended to the chain.
 420          */
 421         if ((m->m_flags & M_IP6_NEXTHOP) &&
 422             (fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL)) != NULL) {
 423                 struct sockaddr_in6 *next_hop6;
 424
 425                 next_hop6 = (struct sockaddr_in6 *)(fwd_tag + 1);
 426
 427                 /*
 428                  * Transparently forwarded. Pretend to be the destination.
 429                  * Already got one like this?
 430                  */
 431                 inp = in6_pcblookup_mbuf(pcbinfo, &ip6->ip6_src,
 432                     uh->uh_sport, &ip6->ip6_dst, uh->uh_dport,
 433                     INPLOOKUP_RLOCKPCB, m->m_pkthdr.rcvif, m);
 434                 if (!inp) {
 435                         /*
 436                          * It's new.  Try to find the ambushing socket.
 437                          * Because we've rewritten the destination address,
 438                          * any hardware-generated hash is ignored.
 439                          */
 440                         inp = in6_pcblookup(pcbinfo, &ip6->ip6_src,
 441                             uh->uh_sport, &next_hop6->sin6_addr,
 442                             next_hop6->sin6_port ? htons(next_hop6->sin6_port) :
 443                             uh->uh_dport, INPLOOKUP_WILDCARD |
 444                             INPLOOKUP_RLOCKPCB, m->m_pkthdr.rcvif);
 445                 }
 446                 /* Remove the tag from the packet. We don't need it anymore. */
 447                 m_tag_delete(m, fwd_tag);
 448                 m->m_flags &= ~M_IP6_NEXTHOP;
 449         } else
 450                 inp = in6_pcblookup_mbuf(pcbinfo, &ip6->ip6_src,
 451                     uh->uh_sport, &ip6->ip6_dst, uh->uh_dport,
 452                     INPLOOKUP_WILDCARD | INPLOOKUP_RLOCKPCB,
 453                     m->m_pkthdr.rcvif, m);
 454         if (inp == NULL) {
 455                 if (udp_log_in_vain) {
 456                         char ip6bufs[INET6_ADDRSTRLEN];
 457                         char ip6bufd[INET6_ADDRSTRLEN];
 458
 459                         log(LOG_INFO,
 460                             "Connection attempt to UDP [%s]:%d from [%s]:%d\n",
 461                             ip6_sprintf(ip6bufd, &ip6->ip6_dst),
 462                             ntohs(uh->uh_dport),
 463                             ip6_sprintf(ip6bufs, &ip6->ip6_src),
 464                             ntohs(uh->uh_sport));
 465                 }
 466                 UDPSTAT_INC(udps_noport);
 467                 if (m->m_flags & M_MCAST) {
 468                         printf("UDP6: M_MCAST is set in a unicast packet.\n");
 469                         UDPSTAT_INC(udps_noportmcast);
 470                         goto badunlocked;
 471                 }
 472                 if (V_udp_blackhole)
 473                         goto badunlocked;
 474                 if (badport_bandlim(BANDLIM_ICMP6_UNREACH) < 0)
 475                         goto badunlocked;
 476                 icmp6_error(m, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOPORT, 0);
 477                 return (IPPROTO_DONE);
 478         }
 479         INP_RLOCK_ASSERT(inp);
 480         up = intoudpcb(inp);
 481         if (cscov_partial) {
 482                 if (up->u_rxcslen > ulen) {
 483                         INP_RUNLOCK(inp);
 484                         m_freem(m);
 485                         return (IPPROTO_DONE);
 486                 }
 487         }
 488         UDP_PROBE(receive, NULL, inp, ip6, inp, uh);
 489         if (up->u_tun_func == NULL) {
 490                 udp6_append(inp, m, off, &fromsa);
 491         } else {
 492                 /*
 493                  * Engage the tunneling protocol.
 494                  */
 495
 496                 (*up->u_tun_func)(m, off, inp);
 497         }
 498         INP_RUNLOCK(inp);
 499         return (IPPROTO_DONE);
 500
 501 badheadlocked:
 502         INP_INFO_RUNLOCK(pcbinfo);
 503 badunlocked:
 504         if (m)
 505                 m_freem(m);
 506         return (IPPROTO_DONE);
 507 }
 508
 509 static void
 510 udp6_common_ctlinput(int cmd, struct sockaddr *sa, void *d,
 511     struct inpcbinfo *pcbinfo)
 512 {
 513         struct udphdr uh;
 514         struct ip6_hdr *ip6;
 515         struct mbuf *m;
 516         int off = 0;
 517         struct ip6ctlparam *ip6cp = NULL;
 518         const struct sockaddr_in6 *sa6_src = NULL;
 519         void *cmdarg;
 520         struct inpcb *(*notify)(struct inpcb *, int) = udp_notify;
 521         struct udp_portonly {
 522                 u_int16_t uh_sport;
 523                 u_int16_t uh_dport;
 524         } *uhp;
 525
 526         if (sa->sa_family != AF_INET6 ||
 527             sa->sa_len != sizeof(struct sockaddr_in6))
 528                 return;
 529
 530         if ((unsigned)cmd >= PRC_NCMDS)
 531                 return;
 532         if (PRC_IS_REDIRECT(cmd))
 533                 notify = in6_rtchange, d = NULL;
 534         else if (cmd == PRC_HOSTDEAD)
 535                 d = NULL;
 536         else if (inet6ctlerrmap[cmd] == 0)
 537                 return;
 538
 539         /* if the parameter is from icmp6, decode it. */
 540         if (d != NULL) {
 541                 ip6cp = (struct ip6ctlparam *)d;
 542                 m = ip6cp->ip6c_m;
 543                 ip6 = ip6cp->ip6c_ip6;
 544                 off = ip6cp->ip6c_off;
 545                 cmdarg = ip6cp->ip6c_cmdarg;
 546                 sa6_src = ip6cp->ip6c_src;
 547         } else {
 548                 m = NULL;
 549                 ip6 = NULL;
 550                 cmdarg = NULL;
 551                 sa6_src = &sa6_any;
 552         }
 553
 554         if (ip6) {
 555                 /*
 556                  * XXX: We assume that when IPV6 is non NULL,
 557                  * M and OFF are valid.
 558                  */
 559
 560                 /* Check if we can safely examine src and dst ports. */
 561                 if (m->m_pkthdr.len < off + sizeof(*uhp))
 562                         return;
 563
 564                 bzero(&uh, sizeof(uh));
 565                 m_copydata(m, off, sizeof(*uhp), (caddr_t)&uh);
 566
 567                 (void)in6_pcbnotify(pcbinfo, sa, uh.uh_dport,
 568                     (struct sockaddr *)ip6cp->ip6c_src, uh.uh_sport, cmd,
 569                     cmdarg, notify);
 570         } else
 571                 (void)in6_pcbnotify(pcbinfo, sa, 0,
 572                     (const struct sockaddr *)sa6_src, 0, cmd, cmdarg, notify);
 573 }
 574
 575 void
 576 udp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
 577 {
 578
 579         return (udp6_common_ctlinput(cmd, sa, d, &V_udbinfo));
 580 }
 581
 582 void
 583 udplite6_ctlinput(int cmd, struct sockaddr *sa, void *d)
 584 {
 585
 586         return (udp6_common_ctlinput(cmd, sa, d, &V_ulitecbinfo));
 587 }
 588
 589 static int
 590 udp6_getcred(SYSCTL_HANDLER_ARGS)
 591 {
 592         struct xucred xuc;
 593         struct sockaddr_in6 addrs[2];
 594         struct inpcb *inp;
 595         int error;
 596
 597         error = priv_check(req->td, PRIV_NETINET_GETCRED);
 598         if (error)
 599                 return (error);
 600
 601         if (req->newlen != sizeof(addrs))
 602                 return (EINVAL);
 603         if (req->oldlen != sizeof(struct xucred))
 604                 return (EINVAL);
 605         error = SYSCTL_IN(req, addrs, sizeof(addrs));
 606         if (error)
 607                 return (error);
 608         if ((error = sa6_embedscope(&addrs[0], V_ip6_use_defzone)) != 0 ||
 609             (error = sa6_embedscope(&addrs[1], V_ip6_use_defzone)) != 0) {
 610                 return (error);
 611         }
 612         inp = in6_pcblookup(&V_udbinfo, &addrs[1].sin6_addr,
 613             addrs[1].sin6_port, &addrs[0].sin6_addr, addrs[0].sin6_port,
 614             INPLOOKUP_WILDCARD | INPLOOKUP_RLOCKPCB, NULL);
 615         if (inp != NULL) {
 616                 INP_RLOCK_ASSERT(inp);
 617                 if (inp->inp_socket == NULL)
 618                         error = ENOENT;
 619                 if (error == 0)
 620                         error = cr_canseesocket(req->td->td_ucred,
 621                             inp->inp_socket);
 622                 if (error == 0)
 623                         cru2x(inp->inp_cred, &xuc);
 624                 INP_RUNLOCK(inp);
 625         } else
 626                 error = ENOENT;
 627         if (error == 0)
 628                 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
 629         return (error);
 630 }
 631
 632 SYSCTL_PROC(_net_inet6_udp6, OID_AUTO, getcred, CTLTYPE_OPAQUE|CTLFLAG_RW, 0,
 633     0, udp6_getcred, "S,xucred", "Get the xucred of a UDP6 connection");
 634
 635 static int
 636 udp6_output(struct inpcb *inp, struct mbuf *m, struct sockaddr *addr6,
 637     struct mbuf *control, struct thread *td)
 638 {
 639         u_int32_t ulen = m->m_pkthdr.len;
 640         u_int32_t plen = sizeof(struct udphdr) + ulen;
 641         struct ip6_hdr *ip6;
 642         struct udphdr *udp6;
 643         struct in6_addr *laddr, *faddr, in6a;
 644         struct sockaddr_in6 *sin6 = NULL;
 645         struct ifnet *oifp = NULL;
 646         int cscov_partial = 0;
 647         int scope_ambiguous = 0;
 648         u_short fport;
 649         int error = 0;
 650         uint8_t nxt;
 651         uint16_t cscov = 0;
 652         struct ip6_pktopts *optp, opt;
 653         int af = AF_INET6, hlen = sizeof(struct ip6_hdr);
 654         int flags;
 655         struct sockaddr_in6 tmp;
 656
 657         INP_WLOCK_ASSERT(inp);
 658         INP_HASH_WLOCK_ASSERT(inp->inp_pcbinfo);
 659
 660         if (addr6) {
 661                 /* addr6 has been validated in udp6_send(). */
 662                 sin6 = (struct sockaddr_in6 *)addr6;
 663
 664                 /* protect *sin6 from overwrites */
 665                 tmp = *sin6;
 666                 sin6 = &tmp;
 667
 668                 /*
 669                  * Application should provide a proper zone ID or the use of
 670                  * default zone IDs should be enabled.  Unfortunately, some
 671                  * applications do not behave as it should, so we need a
 672                  * workaround.  Even if an appropriate ID is not determined,
 673                  * we'll see if we can determine the outgoing interface.  If we
 674                  * can, determine the zone ID based on the interface below.
 675                  */
 676                 if (sin6->sin6_scope_id == 0 && !V_ip6_use_defzone)
 677                         scope_ambiguous = 1;
 678                 if ((error = sa6_embedscope(sin6, V_ip6_use_defzone)) != 0)
 679                         return (error);
 680         }
 681
 682         if (control) {
 683                 if ((error = ip6_setpktopts(control, &opt,
 684                     inp->in6p_outputopts, td->td_ucred, IPPROTO_UDP)) != 0)
 685                         goto release;
 686                 optp = &opt;
 687         } else
 688                 optp = inp->in6p_outputopts;
 689
 690         if (sin6) {
 691                 faddr = &sin6->sin6_addr;
 692
 693                 /*
 694                  * Since we saw no essential reason for calling in_pcbconnect,
 695                  * we get rid of such kind of logic, and call in6_selectsrc
 696                  * and in6_pcbsetport in order to fill in the local address
 697                  * and the local port.
 698                  */
 699                 if (sin6->sin6_port == 0) {
 700                         error = EADDRNOTAVAIL;
 701                         goto release;
 702                 }
 703
 704                 if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
 705                         /* how about ::ffff:0.0.0.0 case? */
 706                         error = EISCONN;
 707                         goto release;
 708                 }
 709
 710                 fport = sin6->sin6_port; /* allow 0 port */
 711
 712                 if (IN6_IS_ADDR_V4MAPPED(faddr)) {
 713                         if ((inp->inp_flags & IN6P_IPV6_V6ONLY)) {
 714                                 /*
 715                                  * I believe we should explicitly discard the
 716                                  * packet when mapped addresses are disabled,
 717                                  * rather than send the packet as an IPv6 one.
 718                                  * If we chose the latter approach, the packet
 719                                  * might be sent out on the wire based on the
 720                                  * default route, the situation which we'd
 721                                  * probably want to avoid.
 722                                  * (20010421 jinmei@kame.net)
 723                                  */
 724                                 error = EINVAL;
 725                                 goto release;
 726                         }
 727                         if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr) &&
 728                             !IN6_IS_ADDR_V4MAPPED(&inp->in6p_laddr)) {
 729                                 /*
 730                                  * when remote addr is an IPv4-mapped address,
 731                                  * local addr should not be an IPv6 address,
 732                                  * since you cannot determine how to map IPv6
 733                                  * source address to IPv4.
 734                                  */
 735                                 error = EINVAL;
 736                                 goto release;
 737                         }
 738
 739                         af = AF_INET;
 740                 }
 741
 742                 if (!IN6_IS_ADDR_V4MAPPED(faddr)) {
 743                         error = in6_selectsrc(sin6, optp, inp, NULL,
 744                             td->td_ucred, &oifp, &in6a);
 745                         if (error)
 746                                 goto release;
 747                         if (oifp && scope_ambiguous &&
 748                             (error = in6_setscope(&sin6->sin6_addr,
 749                             oifp, NULL))) {
 750                                 goto release;
 751                         }
 752                         laddr = &in6a;
 753                 } else
 754                         laddr = &inp->in6p_laddr;       /* XXX */
 755                 if (laddr == NULL) {
 756                         if (error == 0)
 757                                 error = EADDRNOTAVAIL;
 758                         goto release;
 759                 }
 760                 if (inp->inp_lport == 0 &&
 761                     (error = in6_pcbsetport(laddr, inp, td->td_ucred)) != 0) {
 762                         /* Undo an address bind that may have occurred. */
 763                         inp->in6p_laddr = in6addr_any;
 764                         goto release;
 765                 }
 766         } else {
 767                 if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
 768                         error = ENOTCONN;
 769                         goto release;
 770                 }
 771                 if (IN6_IS_ADDR_V4MAPPED(&inp->in6p_faddr)) {
 772                         if ((inp->inp_flags & IN6P_IPV6_V6ONLY)) {
 773                                 /*
 774                                  * XXX: this case would happen when the
 775                                  * application sets the V6ONLY flag after
 776                                  * connecting the foreign address.
 777                                  * Such applications should be fixed,
 778                                  * so we bark here.
 779                                  */
 780                                 log(LOG_INFO, "udp6_output: IPV6_V6ONLY "
 781                                     "option was set for a connected socket\n");
 782                                 error = EINVAL;
 783                                 goto release;
 784                         } else
 785                                 af = AF_INET;
 786                 }
 787                 laddr = &inp->in6p_laddr;
 788                 faddr = &inp->in6p_faddr;
 789                 fport = inp->inp_fport;
 790         }
 791
 792         if (af == AF_INET)
 793                 hlen = sizeof(struct ip);
 794
 795         /*
 796          * Calculate data length and get a mbuf
 797          * for UDP and IP6 headers.
 798          */
 799         M_PREPEND(m, hlen + sizeof(struct udphdr), M_NOWAIT);
 800         if (m == 0) {
 801                 error = ENOBUFS;
 802                 goto release;
 803         }
 804
 805         /*
 806          * Stuff checksum and output datagram.
 807          */
 808         nxt = (inp->inp_socket->so_proto->pr_protocol == IPPROTO_UDP) ?
 809             IPPROTO_UDP : IPPROTO_UDPLITE;
 810         udp6 = (struct udphdr *)(mtod(m, caddr_t) + hlen);
 811         udp6->uh_sport = inp->inp_lport; /* lport is always set in the PCB */
 812         udp6->uh_dport = fport;
 813         if (nxt == IPPROTO_UDPLITE) {
 814                 struct udpcb *up;
 815
 816                 up = intoudpcb(inp);
 817                 cscov = up->u_txcslen;
 818                 if (cscov >= plen)
 819                         cscov = 0;
 820                 udp6->uh_ulen = htons(cscov);
 821                 /*
 822                  * For UDP-Lite, checksum coverage length of zero means
 823                  * the entire UDPLite packet is covered by the checksum.
 824                  */
 825                 cscov_partial = (cscov == 0) ? 0 : 1;
 826         } else if (plen <= 0xffff)
 827                 udp6->uh_ulen = htons((u_short)plen);
 828         else
 829                 udp6->uh_ulen = 0;
 830         udp6->uh_sum = 0;
 831
 832         switch (af) {
 833         case AF_INET6:
 834                 ip6 = mtod(m, struct ip6_hdr *);
 835                 ip6->ip6_flow   = inp->inp_flow & IPV6_FLOWINFO_MASK;
 836                 ip6->ip6_vfc    &= ~IPV6_VERSION_MASK;
 837                 ip6->ip6_vfc    |= IPV6_VERSION;
 838                 ip6->ip6_plen   = htons((u_short)plen);
 839                 ip6->ip6_nxt    = nxt;
 840                 ip6->ip6_hlim   = in6_selecthlim(inp, NULL);
 841                 ip6->ip6_src    = *laddr;
 842                 ip6->ip6_dst    = *faddr;
 843
 844                 if (cscov_partial) {
 845                         if ((udp6->uh_sum = in6_cksum(m, 0,
 846                             sizeof(struct ip6_hdr), cscov)) == 0)
 847                                 udp6->uh_sum = 0xffff;
 848                 } else {
 849                         udp6->uh_sum = in6_cksum_pseudo(ip6, plen, nxt, 0);
 850                         m->m_pkthdr.csum_flags = CSUM_UDP_IPV6;
 851                         m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
 852                 }
 853
 854                 flags = 0;
 855
 856                 UDP_PROBE(send, NULL, inp, ip6, inp, udp6);
 857                 UDPSTAT_INC(udps_opackets);
 858                 error = ip6_output(m, optp, NULL, flags, inp->in6p_moptions,
 859                     NULL, inp);
 860                 break;
 861         case AF_INET:
 862                 error = EAFNOSUPPORT;
 863                 goto release;
 864         }
 865         goto releaseopt;
 866
 867 release:
 868         m_freem(m);
 869
 870 releaseopt:
 871         if (control) {
 872                 ip6_clearpktopts(&opt, -1);
 873                 m_freem(control);
 874         }
 875         return (error);
 876 }
 877
 878 static void
 879 udp6_abort(struct socket *so)
 880 {
 881         struct inpcb *inp;
 882         struct inpcbinfo *pcbinfo;
 883
 884         pcbinfo = get_inpcbinfo(so->so_proto->pr_protocol);
 885         inp = sotoinpcb(so);
 886         KASSERT(inp != NULL, ("udp6_abort: inp == NULL"));
 887
 888 #ifdef INET
 889         if (inp->inp_vflag & INP_IPV4) {
 890                 struct pr_usrreqs *pru;
 891
 892                 pru = inetsw[ip_protox[IPPROTO_UDP]].pr_usrreqs;
 893                 (*pru->pru_abort)(so);
 894                 return;
 895         }
 896 #endif
 897
 898         INP_WLOCK(inp);
 899         if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
 900                 INP_HASH_WLOCK(pcbinfo);
 901                 in6_pcbdisconnect(inp);
 902                 inp->in6p_laddr = in6addr_any;
 903                 INP_HASH_WUNLOCK(pcbinfo);
 904                 soisdisconnected(so);
 905         }
 906         INP_WUNLOCK(inp);
 907 }
 908
 909 static int
 910 udp6_attach(struct socket *so, int proto, struct thread *td)
 911 {
 912         struct inpcb *inp;
 913         struct inpcbinfo *pcbinfo;
 914         int error;
 915
 916         pcbinfo = get_inpcbinfo(so->so_proto->pr_protocol);
 917         inp = sotoinpcb(so);
 918         KASSERT(inp == NULL, ("udp6_attach: inp != NULL"));
 919
 920         if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
 921                 error = soreserve(so, udp_sendspace, udp_recvspace);
 922                 if (error)
 923                         return (error);
 924         }
 925         INP_INFO_WLOCK(pcbinfo);
 926         error = in_pcballoc(so, pcbinfo);
 927         if (error) {
 928                 INP_INFO_WUNLOCK(pcbinfo);
 929                 return (error);
 930         }
 931         inp = (struct inpcb *)so->so_pcb;
 932         inp->inp_vflag |= INP_IPV6;
 933         if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0)
 934                 inp->inp_vflag |= INP_IPV4;
 935         inp->in6p_hops = -1;    /* use kernel default */
 936         inp->in6p_cksum = -1;   /* just to be sure */
 937         /*
 938          * XXX: ugly!!
 939          * IPv4 TTL initialization is necessary for an IPv6 socket as well,
 940          * because the socket may be bound to an IPv6 wildcard address,
 941          * which may match an IPv4-mapped IPv6 address.
 942          */
 943         inp->inp_ip_ttl = V_ip_defttl;
 944
 945         error = udp_newudpcb(inp);
 946         if (error) {
 947                 in_pcbdetach(inp);
 948                 in_pcbfree(inp);
 949                 INP_INFO_WUNLOCK(pcbinfo);
 950                 return (error);
 951         }
 952         INP_WUNLOCK(inp);
 953         INP_INFO_WUNLOCK(pcbinfo);
 954         return (0);
 955 }
 956
 957 static int
 958 udp6_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
 959 {
 960         struct inpcb *inp;
 961         struct inpcbinfo *pcbinfo;
 962         int error;
 963
 964         pcbinfo = get_inpcbinfo(so->so_proto->pr_protocol);
 965         inp = sotoinpcb(so);
 966         KASSERT(inp != NULL, ("udp6_bind: inp == NULL"));
 967
 968         INP_WLOCK(inp);
 969         INP_HASH_WLOCK(pcbinfo);
 970         inp->inp_vflag &= ~INP_IPV4;
 971         inp->inp_vflag |= INP_IPV6;
 972         if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0) {
 973                 struct sockaddr_in6 *sin6_p;
 974
 975                 sin6_p = (struct sockaddr_in6 *)nam;
 976
 977                 if (IN6_IS_ADDR_UNSPECIFIED(&sin6_p->sin6_addr))
 978                         inp->inp_vflag |= INP_IPV4;
 979 #ifdef INET
 980                 else if (IN6_IS_ADDR_V4MAPPED(&sin6_p->sin6_addr)) {
 981                         struct sockaddr_in sin;
 982
 983                         in6_sin6_2_sin(&sin, sin6_p);
 984                         inp->inp_vflag |= INP_IPV4;
 985                         inp->inp_vflag &= ~INP_IPV6;
 986                         error = in_pcbbind(inp, (struct sockaddr *)&sin,
 987                             td->td_ucred);
 988                         goto out;
 989                 }
 990 #endif
 991         }
 992
 993         error = in6_pcbbind(inp, nam, td->td_ucred);
 994 #ifdef INET
 995 out:
 996 #endif
 997         INP_HASH_WUNLOCK(pcbinfo);
 998         INP_WUNLOCK(inp);
 999         return (error);
1000 }
1001
1002 static void
1003 udp6_close(struct socket *so)
1004 {
1005         struct inpcb *inp;
1006         struct inpcbinfo *pcbinfo;
1007
1008         pcbinfo = get_inpcbinfo(so->so_proto->pr_protocol);
1009         inp = sotoinpcb(so);
1010         KASSERT(inp != NULL, ("udp6_close: inp == NULL"));
1011
1012 #ifdef INET
1013         if (inp->inp_vflag & INP_IPV4) {
1014                 struct pr_usrreqs *pru;
1015
1016                 pru = inetsw[ip_protox[IPPROTO_UDP]].pr_usrreqs;
1017                 (*pru->pru_disconnect)(so);
1018                 return;
1019         }
1020 #endif
1021         INP_WLOCK(inp);
1022         if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
1023                 INP_HASH_WLOCK(pcbinfo);
1024                 in6_pcbdisconnect(inp);
1025                 inp->in6p_laddr = in6addr_any;
1026                 INP_HASH_WUNLOCK(pcbinfo);
1027                 soisdisconnected(so);
1028         }
1029         INP_WUNLOCK(inp);
1030 }
1031
1032 static int
1033 udp6_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
1034 {
1035         struct inpcb *inp;
1036         struct inpcbinfo *pcbinfo;
1037         struct sockaddr_in6 *sin6;
1038         int error;
1039
1040         pcbinfo = get_inpcbinfo(so->so_proto->pr_protocol);
1041         inp = sotoinpcb(so);
1042         sin6 = (struct sockaddr_in6 *)nam;
1043         KASSERT(inp != NULL, ("udp6_connect: inp == NULL"));
1044
1045         /*
1046          * XXXRW: Need to clarify locking of v4/v6 flags.
1047          */
1048         INP_WLOCK(inp);
1049 #ifdef INET
1050         if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) {
1051                 struct sockaddr_in sin;
1052
1053                 if ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0) {
1054                         error = EINVAL;
1055                         goto out;
1056                 }
1057                 if (inp->inp_faddr.s_addr != INADDR_ANY) {
1058                         error = EISCONN;
1059                         goto out;
1060                 }
1061                 in6_sin6_2_sin(&sin, sin6);
1062                 inp->inp_vflag |= INP_IPV4;
1063                 inp->inp_vflag &= ~INP_IPV6;
1064                 error = prison_remote_ip4(td->td_ucred, &sin.sin_addr);
1065                 if (error != 0)
1066                         goto out;
1067                 INP_HASH_WLOCK(pcbinfo);
1068                 error = in_pcbconnect(inp, (struct sockaddr *)&sin,
1069                     td->td_ucred);
1070                 INP_HASH_WUNLOCK(pcbinfo);
1071                 if (error == 0)
1072                         soisconnected(so);
1073                 goto out;
1074         }
1075 #endif
1076         if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
1077                 error = EISCONN;
1078                 goto out;
1079         }
1080         inp->inp_vflag &= ~INP_IPV4;
1081         inp->inp_vflag |= INP_IPV6;
1082         error = prison_remote_ip6(td->td_ucred, &sin6->sin6_addr);
1083         if (error != 0)
1084                 goto out;
1085         INP_HASH_WLOCK(pcbinfo);
1086         error = in6_pcbconnect(inp, nam, td->td_ucred);
1087         INP_HASH_WUNLOCK(pcbinfo);
1088         if (error == 0)
1089                 soisconnected(so);
1090 out:
1091         INP_WUNLOCK(inp);
1092         return (error);
1093 }
1094
1095 static void
1096 udp6_detach(struct socket *so)
1097 {
1098         struct inpcb *inp;
1099         struct inpcbinfo *pcbinfo;
1100         struct udpcb *up;
1101
1102         pcbinfo = get_inpcbinfo(so->so_proto->pr_protocol);
1103         inp = sotoinpcb(so);
1104         KASSERT(inp != NULL, ("udp6_detach: inp == NULL"));
1105
1106         INP_INFO_WLOCK(pcbinfo);
1107         INP_WLOCK(inp);
1108         up = intoudpcb(inp);
1109         KASSERT(up != NULL, ("%s: up == NULL", __func__));
1110         in_pcbdetach(inp);
1111         in_pcbfree(inp);
1112         INP_INFO_WUNLOCK(pcbinfo);
1113         udp_discardcb(up);
1114 }
1115
1116 static int
1117 udp6_disconnect(struct socket *so)
1118 {
1119         struct inpcb *inp;
1120         struct inpcbinfo *pcbinfo;
1121         int error;
1122
1123         pcbinfo = get_inpcbinfo(so->so_proto->pr_protocol);
1124         inp = sotoinpcb(so);
1125         KASSERT(inp != NULL, ("udp6_disconnect: inp == NULL"));
1126
1127 #ifdef INET
1128         if (inp->inp_vflag & INP_IPV4) {
1129                 struct pr_usrreqs *pru;
1130
1131                 pru = inetsw[ip_protox[IPPROTO_UDP]].pr_usrreqs;
1132                 (void)(*pru->pru_disconnect)(so);
1133                 return (0);
1134         }
1135 #endif
1136
1137         INP_WLOCK(inp);
1138
1139         if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
1140                 error = ENOTCONN;
1141                 goto out;
1142         }
1143
1144         INP_HASH_WLOCK(pcbinfo);
1145         in6_pcbdisconnect(inp);
1146         inp->in6p_laddr = in6addr_any;
1147         INP_HASH_WUNLOCK(pcbinfo);
1148         SOCK_LOCK(so);
1149         so->so_state &= ~SS_ISCONNECTED;                /* XXX */
1150         SOCK_UNLOCK(so);
1151 out:
1152         INP_WUNLOCK(inp);
1153         return (0);
1154 }
1155
1156 static int
1157 udp6_send(struct socket *so, int flags, struct mbuf *m,
1158     struct sockaddr *addr, struct mbuf *control, struct thread *td)
1159 {
1160         struct inpcb *inp;
1161         struct inpcbinfo *pcbinfo;
1162         int error = 0;
1163
1164         pcbinfo = get_inpcbinfo(so->so_proto->pr_protocol);
1165         inp = sotoinpcb(so);
1166         KASSERT(inp != NULL, ("udp6_send: inp == NULL"));
1167
1168         INP_WLOCK(inp);
1169         if (addr) {
1170                 if (addr->sa_len != sizeof(struct sockaddr_in6)) {
1171                         error = EINVAL;
1172                         goto bad;
1173                 }
1174                 if (addr->sa_family != AF_INET6) {
1175                         error = EAFNOSUPPORT;
1176                         goto bad;
1177                 }
1178         }
1179
1180 #ifdef INET
1181         if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0) {
1182                 int hasv4addr;
1183                 struct sockaddr_in6 *sin6 = 0;
1184
1185                 if (addr == 0)
1186                         hasv4addr = (inp->inp_vflag & INP_IPV4);
1187                 else {
1188                         sin6 = (struct sockaddr_in6 *)addr;
1189                         hasv4addr = IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)
1190                             ? 1 : 0;
1191                 }
1192                 if (hasv4addr) {
1193                         struct pr_usrreqs *pru;
1194
1195                         /*
1196                          * XXXRW: We release UDP-layer locks before calling
1197                          * udp_send() in order to avoid recursion.  However,
1198                          * this does mean there is a short window where inp's
1199                          * fields are unstable.  Could this lead to a
1200                          * potential race in which the factors causing us to
1201                          * select the UDPv4 output routine are invalidated?
1202                          */
1203                         INP_WUNLOCK(inp);
1204                         if (sin6)
1205                                 in6_sin6_2_sin_in_sock(addr);
1206                         pru = inetsw[ip_protox[IPPROTO_UDP]].pr_usrreqs;
1207                         /* addr will just be freed in sendit(). */
1208                         return ((*pru->pru_send)(so, flags, m, addr, control,
1209                             td));
1210                 }
1211         }
1212 #endif
1213 #ifdef MAC
1214         mac_inpcb_create_mbuf(inp, m);
1215 #endif
1216         INP_HASH_WLOCK(pcbinfo);
1217         error = udp6_output(inp, m, addr, control, td);
1218         INP_HASH_WUNLOCK(pcbinfo);
1219 #ifdef INET
1220 #endif
1221         INP_WUNLOCK(inp);
1222         return (error);
1223
1224 bad:
1225         INP_WUNLOCK(inp);
1226         m_freem(m);
1227         return (error);
1228 }
1229
1230 struct pr_usrreqs udp6_usrreqs = {
1231         .pru_abort =            udp6_abort,
1232         .pru_attach =           udp6_attach,
1233         .pru_bind =             udp6_bind,
1234         .pru_connect =          udp6_connect,
1235         .pru_control =          in6_control,
1236         .pru_detach =           udp6_detach,
1237         .pru_disconnect =       udp6_disconnect,
1238         .pru_peeraddr =         in6_mapped_peeraddr,
1239         .pru_send =             udp6_send,
1240         .pru_shutdown =         udp_shutdown,
1241         .pru_sockaddr =         in6_mapped_sockaddr,
1242         .pru_soreceive =        soreceive_dgram,
1243         .pru_sosend =           sosend_dgram,
1244         .pru_sosetlabel =       in_pcbsosetlabel,
1245         .pru_close =            udp6_close
1246 };