xref: /freebsd/sys/netinet6/udp6_usrreq.c (revision 9fc5c47fa5c7fa58d61245f0408611943e613164)
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_rss.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_var.h>
98 #include <net/if_types.h>
99 #include <net/route.h>
100 #include <net/rss_config.h>
101 
102 #include <netinet/in.h>
103 #include <netinet/in_kdtrace.h>
104 #include <netinet/in_pcb.h>
105 #include <netinet/in_systm.h>
106 #include <netinet/in_var.h>
107 #include <netinet/ip.h>
108 #include <netinet/ip_icmp.h>
109 #include <netinet/ip6.h>
110 #include <netinet/icmp_var.h>
111 #include <netinet/icmp6.h>
112 #include <netinet/ip_var.h>
113 #include <netinet/udp.h>
114 #include <netinet/udp_var.h>
115 #include <netinet/udplite.h>
116 
117 #include <netinet6/ip6protosw.h>
118 #include <netinet6/ip6_var.h>
119 #include <netinet6/in6_pcb.h>
120 #include <netinet6/in6_rss.h>
121 #include <netinet6/udp6_var.h>
122 #include <netinet6/scope6_var.h>
123 
124 #ifdef IPSEC
125 #include <netipsec/ipsec.h>
126 #include <netipsec/ipsec6.h>
127 #endif /* IPSEC */
128 
129 #include <security/mac/mac_framework.h>
130 
131 /*
132  * UDP protocol implementation.
133  * Per RFC 768, August, 1980.
134  */
135 
136 extern struct protosw	inetsw[];
137 static void		udp6_detach(struct socket *so);
138 
139 static int
140 udp6_append(struct inpcb *inp, struct mbuf *n, int off,
141     struct sockaddr_in6 *fromsa)
142 {
143 	struct socket *so;
144 	struct mbuf *opts;
145 	struct udpcb *up;
146 
147 	INP_LOCK_ASSERT(inp);
148 
149 	/*
150 	 * Engage the tunneling protocol.
151 	 */
152 	up = intoudpcb(inp);
153 	if (up->u_tun_func != NULL) {
154 		in_pcbref(inp);
155 		INP_RUNLOCK(inp);
156 		(*up->u_tun_func)(n, off, inp, (struct sockaddr *)fromsa,
157 		    up->u_tun_ctx);
158 		INP_RLOCK(inp);
159 		return (in_pcbrele_rlocked(inp));
160 	}
161 #ifdef IPSEC
162 	/* Check AH/ESP integrity. */
163 	if (ipsec6_in_reject(n, inp)) {
164 		m_freem(n);
165 		return (0);
166 	}
167 #endif /* IPSEC */
168 #ifdef MAC
169 	if (mac_inpcb_check_deliver(inp, n) != 0) {
170 		m_freem(n);
171 		return (0);
172 	}
173 #endif
174 	opts = NULL;
175 	if (inp->inp_flags & INP_CONTROLOPTS ||
176 	    inp->inp_socket->so_options & SO_TIMESTAMP)
177 		ip6_savecontrol(inp, n, &opts);
178 	m_adj(n, off + sizeof(struct udphdr));
179 
180 	so = inp->inp_socket;
181 	SOCKBUF_LOCK(&so->so_rcv);
182 	if (sbappendaddr_locked(&so->so_rcv, (struct sockaddr *)fromsa, n,
183 	    opts) == 0) {
184 		SOCKBUF_UNLOCK(&so->so_rcv);
185 		m_freem(n);
186 		if (opts)
187 			m_freem(opts);
188 		UDPSTAT_INC(udps_fullsock);
189 	} else
190 		sorwakeup_locked(so);
191 	return (0);
192 }
193 
194 int
195 udp6_input(struct mbuf **mp, int *offp, int proto)
196 {
197 	struct mbuf *m = *mp;
198 	struct ifnet *ifp;
199 	struct ip6_hdr *ip6;
200 	struct udphdr *uh;
201 	struct inpcb *inp;
202 	struct inpcbinfo *pcbinfo;
203 	struct udpcb *up;
204 	int off = *offp;
205 	int cscov_partial;
206 	int plen, ulen;
207 	struct sockaddr_in6 fromsa;
208 	struct m_tag *fwd_tag;
209 	uint16_t uh_sum;
210 	uint8_t nxt;
211 
212 	ifp = m->m_pkthdr.rcvif;
213 	ip6 = mtod(m, struct ip6_hdr *);
214 
215 #ifndef PULLDOWN_TEST
216 	IP6_EXTHDR_CHECK(m, off, sizeof(struct udphdr), IPPROTO_DONE);
217 	ip6 = mtod(m, struct ip6_hdr *);
218 	uh = (struct udphdr *)((caddr_t)ip6 + off);
219 #else
220 	IP6_EXTHDR_GET(uh, struct udphdr *, m, off, sizeof(*uh));
221 	if (!uh)
222 		return (IPPROTO_DONE);
223 #endif
224 
225 	UDPSTAT_INC(udps_ipackets);
226 
227 	/*
228 	 * Destination port of 0 is illegal, based on RFC768.
229 	 */
230 	if (uh->uh_dport == 0)
231 		goto badunlocked;
232 
233 	plen = ntohs(ip6->ip6_plen) - off + sizeof(*ip6);
234 	ulen = ntohs((u_short)uh->uh_ulen);
235 
236 	nxt = ip6->ip6_nxt;
237 	cscov_partial = (nxt == IPPROTO_UDPLITE) ? 1 : 0;
238 	if (nxt == IPPROTO_UDPLITE) {
239 		/* Zero means checksum over the complete packet. */
240 		if (ulen == 0)
241 			ulen = plen;
242 		if (ulen == plen)
243 			cscov_partial = 0;
244 		if ((ulen < sizeof(struct udphdr)) || (ulen > plen)) {
245 			/* XXX: What is the right UDPLite MIB counter? */
246 			goto badunlocked;
247 		}
248 		if (uh->uh_sum == 0) {
249 			/* XXX: What is the right UDPLite MIB counter? */
250 			goto badunlocked;
251 		}
252 	} else {
253 		if ((ulen < sizeof(struct udphdr)) || (plen != ulen)) {
254 			UDPSTAT_INC(udps_badlen);
255 			goto badunlocked;
256 		}
257 		if (uh->uh_sum == 0) {
258 			UDPSTAT_INC(udps_nosum);
259 			goto badunlocked;
260 		}
261 	}
262 
263 	if ((m->m_pkthdr.csum_flags & CSUM_DATA_VALID_IPV6) &&
264 	    !cscov_partial) {
265 		if (m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR)
266 			uh_sum = m->m_pkthdr.csum_data;
267 		else
268 			uh_sum = in6_cksum_pseudo(ip6, ulen, nxt,
269 			    m->m_pkthdr.csum_data);
270 		uh_sum ^= 0xffff;
271 	} else
272 		uh_sum = in6_cksum_partial(m, nxt, off, plen, ulen);
273 
274 	if (uh_sum != 0) {
275 		UDPSTAT_INC(udps_badsum);
276 		goto badunlocked;
277 	}
278 
279 	/*
280 	 * Construct sockaddr format source address.
281 	 */
282 	init_sin6(&fromsa, m);
283 	fromsa.sin6_port = uh->uh_sport;
284 
285 	pcbinfo = udp_get_inpcbinfo(nxt);
286 	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
287 		struct inpcb *last;
288 		struct inpcbhead *pcblist;
289 		struct ip6_moptions *imo;
290 
291 		INP_INFO_RLOCK(pcbinfo);
292 		/*
293 		 * In the event that laddr should be set to the link-local
294 		 * address (this happens in RIPng), the multicast address
295 		 * specified in the received packet will not match laddr.  To
296 		 * handle this situation, matching is relaxed if the
297 		 * receiving interface is the same as one specified in the
298 		 * socket and if the destination multicast address matches
299 		 * one of the multicast groups specified in the socket.
300 		 */
301 
302 		/*
303 		 * KAME note: traditionally we dropped udpiphdr from mbuf
304 		 * here.  We need udphdr for IPsec processing so we do that
305 		 * later.
306 		 */
307 		pcblist = udp_get_pcblist(nxt);
308 		last = NULL;
309 		LIST_FOREACH(inp, pcblist, inp_list) {
310 			if ((inp->inp_vflag & INP_IPV6) == 0)
311 				continue;
312 			if (inp->inp_lport != uh->uh_dport)
313 				continue;
314 			if (inp->inp_fport != 0 &&
315 			    inp->inp_fport != uh->uh_sport)
316 				continue;
317 			if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr)) {
318 				if (!IN6_ARE_ADDR_EQUAL(&inp->in6p_laddr,
319 							&ip6->ip6_dst))
320 					continue;
321 			}
322 			if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
323 				if (!IN6_ARE_ADDR_EQUAL(&inp->in6p_faddr,
324 							&ip6->ip6_src) ||
325 				    inp->inp_fport != uh->uh_sport)
326 					continue;
327 			}
328 
329 			/*
330 			 * XXXRW: Because we weren't holding either the inpcb
331 			 * or the hash lock when we checked for a match
332 			 * before, we should probably recheck now that the
333 			 * inpcb lock is (supposed to be) held.
334 			 */
335 
336 			/*
337 			 * Handle socket delivery policy for any-source
338 			 * and source-specific multicast. [RFC3678]
339 			 */
340 			imo = inp->in6p_moptions;
341 			if (imo && IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
342 				struct sockaddr_in6	 mcaddr;
343 				int			 blocked;
344 
345 				INP_RLOCK(inp);
346 
347 				bzero(&mcaddr, sizeof(struct sockaddr_in6));
348 				mcaddr.sin6_len = sizeof(struct sockaddr_in6);
349 				mcaddr.sin6_family = AF_INET6;
350 				mcaddr.sin6_addr = ip6->ip6_dst;
351 
352 				blocked = im6o_mc_filter(imo, ifp,
353 					(struct sockaddr *)&mcaddr,
354 					(struct sockaddr *)&fromsa);
355 				if (blocked != MCAST_PASS) {
356 					if (blocked == MCAST_NOTGMEMBER)
357 						IP6STAT_INC(ip6s_notmember);
358 					if (blocked == MCAST_NOTSMEMBER ||
359 					    blocked == MCAST_MUTED)
360 						UDPSTAT_INC(udps_filtermcast);
361 					INP_RUNLOCK(inp); /* XXX */
362 					continue;
363 				}
364 
365 				INP_RUNLOCK(inp);
366 			}
367 			if (last != NULL) {
368 				struct mbuf *n;
369 
370 				if ((n = m_copy(m, 0, M_COPYALL)) != NULL) {
371 					INP_RLOCK(last);
372 					UDP_PROBE(receive, NULL, last, ip6,
373 					    last, uh);
374 					if (udp6_append(last, n, off, &fromsa))
375 						goto inp_lost;
376 					INP_RUNLOCK(last);
377 				}
378 			}
379 			last = inp;
380 			/*
381 			 * Don't look for additional matches if this one does
382 			 * not have either the SO_REUSEPORT or SO_REUSEADDR
383 			 * socket options set.  This heuristic avoids
384 			 * searching through all pcbs in the common case of a
385 			 * non-shared port.  It assumes that an application
386 			 * will never clear these options after setting them.
387 			 */
388 			if ((last->inp_socket->so_options &
389 			     (SO_REUSEPORT|SO_REUSEADDR)) == 0)
390 				break;
391 		}
392 
393 		if (last == NULL) {
394 			/*
395 			 * No matching pcb found; discard datagram.  (No need
396 			 * to send an ICMP Port Unreachable for a broadcast
397 			 * or multicast datgram.)
398 			 */
399 			UDPSTAT_INC(udps_noport);
400 			UDPSTAT_INC(udps_noportmcast);
401 			goto badheadlocked;
402 		}
403 		INP_RLOCK(last);
404 		INP_INFO_RUNLOCK(pcbinfo);
405 		UDP_PROBE(receive, NULL, last, ip6, last, uh);
406 		if (udp6_append(last, m, off, &fromsa) == 0)
407 			INP_RUNLOCK(last);
408 	inp_lost:
409 		return (IPPROTO_DONE);
410 	}
411 	/*
412 	 * Locate pcb for datagram.
413 	 */
414 
415 	/*
416 	 * Grab info from PACKET_TAG_IPFORWARD tag prepended to the chain.
417 	 */
418 	if ((m->m_flags & M_IP6_NEXTHOP) &&
419 	    (fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL)) != NULL) {
420 		struct sockaddr_in6 *next_hop6;
421 
422 		next_hop6 = (struct sockaddr_in6 *)(fwd_tag + 1);
423 
424 		/*
425 		 * Transparently forwarded. Pretend to be the destination.
426 		 * Already got one like this?
427 		 */
428 		inp = in6_pcblookup_mbuf(pcbinfo, &ip6->ip6_src,
429 		    uh->uh_sport, &ip6->ip6_dst, uh->uh_dport,
430 		    INPLOOKUP_RLOCKPCB, m->m_pkthdr.rcvif, m);
431 		if (!inp) {
432 			/*
433 			 * It's new.  Try to find the ambushing socket.
434 			 * Because we've rewritten the destination address,
435 			 * any hardware-generated hash is ignored.
436 			 */
437 			inp = in6_pcblookup(pcbinfo, &ip6->ip6_src,
438 			    uh->uh_sport, &next_hop6->sin6_addr,
439 			    next_hop6->sin6_port ? htons(next_hop6->sin6_port) :
440 			    uh->uh_dport, INPLOOKUP_WILDCARD |
441 			    INPLOOKUP_RLOCKPCB, m->m_pkthdr.rcvif);
442 		}
443 		/* Remove the tag from the packet. We don't need it anymore. */
444 		m_tag_delete(m, fwd_tag);
445 		m->m_flags &= ~M_IP6_NEXTHOP;
446 	} else
447 		inp = in6_pcblookup_mbuf(pcbinfo, &ip6->ip6_src,
448 		    uh->uh_sport, &ip6->ip6_dst, uh->uh_dport,
449 		    INPLOOKUP_WILDCARD | INPLOOKUP_RLOCKPCB,
450 		    m->m_pkthdr.rcvif, m);
451 	if (inp == NULL) {
452 		if (udp_log_in_vain) {
453 			char ip6bufs[INET6_ADDRSTRLEN];
454 			char ip6bufd[INET6_ADDRSTRLEN];
455 
456 			log(LOG_INFO,
457 			    "Connection attempt to UDP [%s]:%d from [%s]:%d\n",
458 			    ip6_sprintf(ip6bufd, &ip6->ip6_dst),
459 			    ntohs(uh->uh_dport),
460 			    ip6_sprintf(ip6bufs, &ip6->ip6_src),
461 			    ntohs(uh->uh_sport));
462 		}
463 		UDPSTAT_INC(udps_noport);
464 		if (m->m_flags & M_MCAST) {
465 			printf("UDP6: M_MCAST is set in a unicast packet.\n");
466 			UDPSTAT_INC(udps_noportmcast);
467 			goto badunlocked;
468 		}
469 		if (V_udp_blackhole)
470 			goto badunlocked;
471 		if (badport_bandlim(BANDLIM_ICMP6_UNREACH) < 0)
472 			goto badunlocked;
473 		icmp6_error(m, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOPORT, 0);
474 		return (IPPROTO_DONE);
475 	}
476 	INP_RLOCK_ASSERT(inp);
477 	up = intoudpcb(inp);
478 	if (cscov_partial) {
479 		if (up->u_rxcslen == 0 || up->u_rxcslen > ulen) {
480 			INP_RUNLOCK(inp);
481 			m_freem(m);
482 			return (IPPROTO_DONE);
483 		}
484 	}
485 	UDP_PROBE(receive, NULL, inp, ip6, inp, uh);
486 	if (udp6_append(inp, m, off, &fromsa) == 0)
487 		INP_RUNLOCK(inp);
488 	return (IPPROTO_DONE);
489 
490 badheadlocked:
491 	INP_INFO_RUNLOCK(pcbinfo);
492 badunlocked:
493 	if (m)
494 		m_freem(m);
495 	return (IPPROTO_DONE);
496 }
497 
498 static void
499 udp6_common_ctlinput(int cmd, struct sockaddr *sa, void *d,
500     struct inpcbinfo *pcbinfo)
501 {
502 	struct udphdr uh;
503 	struct ip6_hdr *ip6;
504 	struct mbuf *m;
505 	int off = 0;
506 	struct ip6ctlparam *ip6cp = NULL;
507 	const struct sockaddr_in6 *sa6_src = NULL;
508 	void *cmdarg;
509 	struct inpcb *(*notify)(struct inpcb *, int) = udp_notify;
510 	struct udp_portonly {
511 		u_int16_t uh_sport;
512 		u_int16_t uh_dport;
513 	} *uhp;
514 
515 	if (sa->sa_family != AF_INET6 ||
516 	    sa->sa_len != sizeof(struct sockaddr_in6))
517 		return;
518 
519 	if ((unsigned)cmd >= PRC_NCMDS)
520 		return;
521 	if (PRC_IS_REDIRECT(cmd))
522 		notify = in6_rtchange, d = NULL;
523 	else if (cmd == PRC_HOSTDEAD)
524 		d = NULL;
525 	else if (inet6ctlerrmap[cmd] == 0)
526 		return;
527 
528 	/* if the parameter is from icmp6, decode it. */
529 	if (d != NULL) {
530 		ip6cp = (struct ip6ctlparam *)d;
531 		m = ip6cp->ip6c_m;
532 		ip6 = ip6cp->ip6c_ip6;
533 		off = ip6cp->ip6c_off;
534 		cmdarg = ip6cp->ip6c_cmdarg;
535 		sa6_src = ip6cp->ip6c_src;
536 	} else {
537 		m = NULL;
538 		ip6 = NULL;
539 		cmdarg = NULL;
540 		sa6_src = &sa6_any;
541 	}
542 
543 	if (ip6) {
544 		/*
545 		 * XXX: We assume that when IPV6 is non NULL,
546 		 * M and OFF are valid.
547 		 */
548 
549 		/* Check if we can safely examine src and dst ports. */
550 		if (m->m_pkthdr.len < off + sizeof(*uhp))
551 			return;
552 
553 		bzero(&uh, sizeof(uh));
554 		m_copydata(m, off, sizeof(*uhp), (caddr_t)&uh);
555 
556 		(void)in6_pcbnotify(pcbinfo, sa, uh.uh_dport,
557 		    (struct sockaddr *)ip6cp->ip6c_src, uh.uh_sport, cmd,
558 		    cmdarg, notify);
559 	} else
560 		(void)in6_pcbnotify(pcbinfo, sa, 0,
561 		    (const struct sockaddr *)sa6_src, 0, cmd, cmdarg, notify);
562 }
563 
564 void
565 udp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
566 {
567 
568 	return (udp6_common_ctlinput(cmd, sa, d, &V_udbinfo));
569 }
570 
571 void
572 udplite6_ctlinput(int cmd, struct sockaddr *sa, void *d)
573 {
574 
575 	return (udp6_common_ctlinput(cmd, sa, d, &V_ulitecbinfo));
576 }
577 
578 static int
579 udp6_getcred(SYSCTL_HANDLER_ARGS)
580 {
581 	struct xucred xuc;
582 	struct sockaddr_in6 addrs[2];
583 	struct inpcb *inp;
584 	int error;
585 
586 	error = priv_check(req->td, PRIV_NETINET_GETCRED);
587 	if (error)
588 		return (error);
589 
590 	if (req->newlen != sizeof(addrs))
591 		return (EINVAL);
592 	if (req->oldlen != sizeof(struct xucred))
593 		return (EINVAL);
594 	error = SYSCTL_IN(req, addrs, sizeof(addrs));
595 	if (error)
596 		return (error);
597 	if ((error = sa6_embedscope(&addrs[0], V_ip6_use_defzone)) != 0 ||
598 	    (error = sa6_embedscope(&addrs[1], V_ip6_use_defzone)) != 0) {
599 		return (error);
600 	}
601 	inp = in6_pcblookup(&V_udbinfo, &addrs[1].sin6_addr,
602 	    addrs[1].sin6_port, &addrs[0].sin6_addr, addrs[0].sin6_port,
603 	    INPLOOKUP_WILDCARD | INPLOOKUP_RLOCKPCB, NULL);
604 	if (inp != NULL) {
605 		INP_RLOCK_ASSERT(inp);
606 		if (inp->inp_socket == NULL)
607 			error = ENOENT;
608 		if (error == 0)
609 			error = cr_canseesocket(req->td->td_ucred,
610 			    inp->inp_socket);
611 		if (error == 0)
612 			cru2x(inp->inp_cred, &xuc);
613 		INP_RUNLOCK(inp);
614 	} else
615 		error = ENOENT;
616 	if (error == 0)
617 		error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
618 	return (error);
619 }
620 
621 SYSCTL_PROC(_net_inet6_udp6, OID_AUTO, getcred, CTLTYPE_OPAQUE|CTLFLAG_RW, 0,
622     0, udp6_getcred, "S,xucred", "Get the xucred of a UDP6 connection");
623 
624 static int
625 udp6_output(struct inpcb *inp, struct mbuf *m, struct sockaddr *addr6,
626     struct mbuf *control, struct thread *td)
627 {
628 	u_int32_t ulen = m->m_pkthdr.len;
629 	u_int32_t plen = sizeof(struct udphdr) + ulen;
630 	struct ip6_hdr *ip6;
631 	struct udphdr *udp6;
632 	struct in6_addr *laddr, *faddr, in6a;
633 	struct sockaddr_in6 *sin6 = NULL;
634 	struct ifnet *oifp = NULL;
635 	int cscov_partial = 0;
636 	int scope_ambiguous = 0;
637 	u_short fport;
638 	int error = 0;
639 	uint8_t nxt;
640 	uint16_t cscov = 0;
641 	struct ip6_pktopts *optp, opt;
642 	int af = AF_INET6, hlen = sizeof(struct ip6_hdr);
643 	int flags;
644 	struct sockaddr_in6 tmp;
645 
646 	INP_WLOCK_ASSERT(inp);
647 	INP_HASH_WLOCK_ASSERT(inp->inp_pcbinfo);
648 
649 	if (addr6) {
650 		/* addr6 has been validated in udp6_send(). */
651 		sin6 = (struct sockaddr_in6 *)addr6;
652 
653 		/* protect *sin6 from overwrites */
654 		tmp = *sin6;
655 		sin6 = &tmp;
656 
657 		/*
658 		 * Application should provide a proper zone ID or the use of
659 		 * default zone IDs should be enabled.  Unfortunately, some
660 		 * applications do not behave as it should, so we need a
661 		 * workaround.  Even if an appropriate ID is not determined,
662 		 * we'll see if we can determine the outgoing interface.  If we
663 		 * can, determine the zone ID based on the interface below.
664 		 */
665 		if (sin6->sin6_scope_id == 0 && !V_ip6_use_defzone)
666 			scope_ambiguous = 1;
667 		if ((error = sa6_embedscope(sin6, V_ip6_use_defzone)) != 0)
668 			return (error);
669 	}
670 
671 	if (control) {
672 		if ((error = ip6_setpktopts(control, &opt,
673 		    inp->in6p_outputopts, td->td_ucred, IPPROTO_UDP)) != 0)
674 			goto release;
675 		optp = &opt;
676 	} else
677 		optp = inp->in6p_outputopts;
678 
679 	if (sin6) {
680 		faddr = &sin6->sin6_addr;
681 
682 		/*
683 		 * Since we saw no essential reason for calling in_pcbconnect,
684 		 * we get rid of such kind of logic, and call in6_selectsrc
685 		 * and in6_pcbsetport in order to fill in the local address
686 		 * and the local port.
687 		 */
688 		if (sin6->sin6_port == 0) {
689 			error = EADDRNOTAVAIL;
690 			goto release;
691 		}
692 
693 		if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
694 			/* how about ::ffff:0.0.0.0 case? */
695 			error = EISCONN;
696 			goto release;
697 		}
698 
699 		fport = sin6->sin6_port; /* allow 0 port */
700 
701 		if (IN6_IS_ADDR_V4MAPPED(faddr)) {
702 			if ((inp->inp_flags & IN6P_IPV6_V6ONLY)) {
703 				/*
704 				 * I believe we should explicitly discard the
705 				 * packet when mapped addresses are disabled,
706 				 * rather than send the packet as an IPv6 one.
707 				 * If we chose the latter approach, the packet
708 				 * might be sent out on the wire based on the
709 				 * default route, the situation which we'd
710 				 * probably want to avoid.
711 				 * (20010421 jinmei@kame.net)
712 				 */
713 				error = EINVAL;
714 				goto release;
715 			}
716 			if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr) &&
717 			    !IN6_IS_ADDR_V4MAPPED(&inp->in6p_laddr)) {
718 				/*
719 				 * when remote addr is an IPv4-mapped address,
720 				 * local addr should not be an IPv6 address,
721 				 * since you cannot determine how to map IPv6
722 				 * source address to IPv4.
723 				 */
724 				error = EINVAL;
725 				goto release;
726 			}
727 
728 			af = AF_INET;
729 		}
730 
731 		if (!IN6_IS_ADDR_V4MAPPED(faddr)) {
732 			error = in6_selectsrc(sin6, optp, inp, NULL,
733 			    td->td_ucred, &oifp, &in6a);
734 			if (error)
735 				goto release;
736 			if (oifp && scope_ambiguous &&
737 			    (error = in6_setscope(&sin6->sin6_addr,
738 			    oifp, NULL))) {
739 				goto release;
740 			}
741 			laddr = &in6a;
742 		} else
743 			laddr = &inp->in6p_laddr;	/* XXX */
744 		if (laddr == NULL) {
745 			if (error == 0)
746 				error = EADDRNOTAVAIL;
747 			goto release;
748 		}
749 		if (inp->inp_lport == 0 &&
750 		    (error = in6_pcbsetport(laddr, inp, td->td_ucred)) != 0) {
751 			/* Undo an address bind that may have occurred. */
752 			inp->in6p_laddr = in6addr_any;
753 			goto release;
754 		}
755 	} else {
756 		if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
757 			error = ENOTCONN;
758 			goto release;
759 		}
760 		if (IN6_IS_ADDR_V4MAPPED(&inp->in6p_faddr)) {
761 			if ((inp->inp_flags & IN6P_IPV6_V6ONLY)) {
762 				/*
763 				 * XXX: this case would happen when the
764 				 * application sets the V6ONLY flag after
765 				 * connecting the foreign address.
766 				 * Such applications should be fixed,
767 				 * so we bark here.
768 				 */
769 				log(LOG_INFO, "udp6_output: IPV6_V6ONLY "
770 				    "option was set for a connected socket\n");
771 				error = EINVAL;
772 				goto release;
773 			} else
774 				af = AF_INET;
775 		}
776 		laddr = &inp->in6p_laddr;
777 		faddr = &inp->in6p_faddr;
778 		fport = inp->inp_fport;
779 	}
780 
781 	if (af == AF_INET)
782 		hlen = sizeof(struct ip);
783 
784 	/*
785 	 * Calculate data length and get a mbuf
786 	 * for UDP and IP6 headers.
787 	 */
788 	M_PREPEND(m, hlen + sizeof(struct udphdr), M_NOWAIT);
789 	if (m == 0) {
790 		error = ENOBUFS;
791 		goto release;
792 	}
793 
794 	/*
795 	 * Stuff checksum and output datagram.
796 	 */
797 	nxt = (inp->inp_socket->so_proto->pr_protocol == IPPROTO_UDP) ?
798 	    IPPROTO_UDP : IPPROTO_UDPLITE;
799 	udp6 = (struct udphdr *)(mtod(m, caddr_t) + hlen);
800 	udp6->uh_sport = inp->inp_lport; /* lport is always set in the PCB */
801 	udp6->uh_dport = fport;
802 	if (nxt == IPPROTO_UDPLITE) {
803 		struct udpcb *up;
804 
805 		up = intoudpcb(inp);
806 		cscov = up->u_txcslen;
807 		if (cscov >= plen)
808 			cscov = 0;
809 		udp6->uh_ulen = htons(cscov);
810 		/*
811 		 * For UDP-Lite, checksum coverage length of zero means
812 		 * the entire UDPLite packet is covered by the checksum.
813 		 */
814 		cscov_partial = (cscov == 0) ? 0 : 1;
815 	} else if (plen <= 0xffff)
816 		udp6->uh_ulen = htons((u_short)plen);
817 	else
818 		udp6->uh_ulen = 0;
819 	udp6->uh_sum = 0;
820 
821 	switch (af) {
822 	case AF_INET6:
823 		ip6 = mtod(m, struct ip6_hdr *);
824 		ip6->ip6_flow	= inp->inp_flow & IPV6_FLOWINFO_MASK;
825 		ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
826 		ip6->ip6_vfc	|= IPV6_VERSION;
827 		ip6->ip6_plen	= htons((u_short)plen);
828 		ip6->ip6_nxt	= nxt;
829 		ip6->ip6_hlim	= in6_selecthlim(inp, NULL);
830 		ip6->ip6_src	= *laddr;
831 		ip6->ip6_dst	= *faddr;
832 
833 		if (cscov_partial) {
834 			if ((udp6->uh_sum = in6_cksum_partial(m, nxt,
835 			    sizeof(struct ip6_hdr), plen, cscov)) == 0)
836 				udp6->uh_sum = 0xffff;
837 		} else {
838 			udp6->uh_sum = in6_cksum_pseudo(ip6, plen, nxt, 0);
839 			m->m_pkthdr.csum_flags = CSUM_UDP_IPV6;
840 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
841 		}
842 
843 #ifdef	RSS
844 		{
845 			uint32_t hash_val, hash_type;
846 			uint8_t pr;
847 
848 			pr = inp->inp_socket->so_proto->pr_protocol;
849 			/*
850 			 * Calculate an appropriate RSS hash for UDP and
851 			 * UDP Lite.
852 			 *
853 			 * The called function will take care of figuring out
854 			 * whether a 2-tuple or 4-tuple hash is required based
855 			 * on the currently configured scheme.
856 			 *
857 			 * Later later on connected socket values should be
858 			 * cached in the inpcb and reused, rather than constantly
859 			 * re-calculating it.
860 			 *
861 			 * UDP Lite is a different protocol number and will
862 			 * likely end up being hashed as a 2-tuple until
863 			 * RSS / NICs grow UDP Lite protocol awareness.
864 			 */
865 			if (rss_proto_software_hash_v6(faddr, laddr, fport,
866 			    inp->inp_lport, pr, &hash_val, &hash_type) == 0) {
867 				m->m_pkthdr.flowid = hash_val;
868 				M_HASHTYPE_SET(m, hash_type);
869 			}
870 		}
871 #endif
872 		flags = 0;
873 #ifdef	RSS
874 		/*
875 		 * Don't override with the inp cached flowid.
876 		 *
877 		 * Until the whole UDP path is vetted, it may actually
878 		 * be incorrect.
879 		 */
880 		flags |= IP_NODEFAULTFLOWID;
881 #endif
882 
883 		UDP_PROBE(send, NULL, inp, ip6, inp, udp6);
884 		UDPSTAT_INC(udps_opackets);
885 		error = ip6_output(m, optp, NULL, flags, inp->in6p_moptions,
886 		    NULL, inp);
887 		break;
888 	case AF_INET:
889 		error = EAFNOSUPPORT;
890 		goto release;
891 	}
892 	goto releaseopt;
893 
894 release:
895 	m_freem(m);
896 
897 releaseopt:
898 	if (control) {
899 		ip6_clearpktopts(&opt, -1);
900 		m_freem(control);
901 	}
902 	return (error);
903 }
904 
905 static void
906 udp6_abort(struct socket *so)
907 {
908 	struct inpcb *inp;
909 	struct inpcbinfo *pcbinfo;
910 
911 	pcbinfo = udp_get_inpcbinfo(so->so_proto->pr_protocol);
912 	inp = sotoinpcb(so);
913 	KASSERT(inp != NULL, ("udp6_abort: inp == NULL"));
914 
915 #ifdef INET
916 	if (inp->inp_vflag & INP_IPV4) {
917 		struct pr_usrreqs *pru;
918 
919 		pru = inetsw[ip_protox[IPPROTO_UDP]].pr_usrreqs;
920 		(*pru->pru_abort)(so);
921 		return;
922 	}
923 #endif
924 
925 	INP_WLOCK(inp);
926 	if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
927 		INP_HASH_WLOCK(pcbinfo);
928 		in6_pcbdisconnect(inp);
929 		inp->in6p_laddr = in6addr_any;
930 		INP_HASH_WUNLOCK(pcbinfo);
931 		soisdisconnected(so);
932 	}
933 	INP_WUNLOCK(inp);
934 }
935 
936 static int
937 udp6_attach(struct socket *so, int proto, struct thread *td)
938 {
939 	struct inpcb *inp;
940 	struct inpcbinfo *pcbinfo;
941 	int error;
942 
943 	pcbinfo = udp_get_inpcbinfo(so->so_proto->pr_protocol);
944 	inp = sotoinpcb(so);
945 	KASSERT(inp == NULL, ("udp6_attach: inp != NULL"));
946 
947 	if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
948 		error = soreserve(so, udp_sendspace, udp_recvspace);
949 		if (error)
950 			return (error);
951 	}
952 	INP_INFO_WLOCK(pcbinfo);
953 	error = in_pcballoc(so, pcbinfo);
954 	if (error) {
955 		INP_INFO_WUNLOCK(pcbinfo);
956 		return (error);
957 	}
958 	inp = (struct inpcb *)so->so_pcb;
959 	inp->inp_vflag |= INP_IPV6;
960 	if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0)
961 		inp->inp_vflag |= INP_IPV4;
962 	inp->in6p_hops = -1;	/* use kernel default */
963 	inp->in6p_cksum = -1;	/* just to be sure */
964 	/*
965 	 * XXX: ugly!!
966 	 * IPv4 TTL initialization is necessary for an IPv6 socket as well,
967 	 * because the socket may be bound to an IPv6 wildcard address,
968 	 * which may match an IPv4-mapped IPv6 address.
969 	 */
970 	inp->inp_ip_ttl = V_ip_defttl;
971 
972 	error = udp_newudpcb(inp);
973 	if (error) {
974 		in_pcbdetach(inp);
975 		in_pcbfree(inp);
976 		INP_INFO_WUNLOCK(pcbinfo);
977 		return (error);
978 	}
979 	INP_WUNLOCK(inp);
980 	INP_INFO_WUNLOCK(pcbinfo);
981 	return (0);
982 }
983 
984 static int
985 udp6_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
986 {
987 	struct inpcb *inp;
988 	struct inpcbinfo *pcbinfo;
989 	int error;
990 
991 	pcbinfo = udp_get_inpcbinfo(so->so_proto->pr_protocol);
992 	inp = sotoinpcb(so);
993 	KASSERT(inp != NULL, ("udp6_bind: inp == NULL"));
994 
995 	INP_WLOCK(inp);
996 	INP_HASH_WLOCK(pcbinfo);
997 	inp->inp_vflag &= ~INP_IPV4;
998 	inp->inp_vflag |= INP_IPV6;
999 	if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0) {
1000 		struct sockaddr_in6 *sin6_p;
1001 
1002 		sin6_p = (struct sockaddr_in6 *)nam;
1003 
1004 		if (IN6_IS_ADDR_UNSPECIFIED(&sin6_p->sin6_addr))
1005 			inp->inp_vflag |= INP_IPV4;
1006 #ifdef INET
1007 		else if (IN6_IS_ADDR_V4MAPPED(&sin6_p->sin6_addr)) {
1008 			struct sockaddr_in sin;
1009 
1010 			in6_sin6_2_sin(&sin, sin6_p);
1011 			inp->inp_vflag |= INP_IPV4;
1012 			inp->inp_vflag &= ~INP_IPV6;
1013 			error = in_pcbbind(inp, (struct sockaddr *)&sin,
1014 			    td->td_ucred);
1015 			goto out;
1016 		}
1017 #endif
1018 	}
1019 
1020 	error = in6_pcbbind(inp, nam, td->td_ucred);
1021 #ifdef INET
1022 out:
1023 #endif
1024 	INP_HASH_WUNLOCK(pcbinfo);
1025 	INP_WUNLOCK(inp);
1026 	return (error);
1027 }
1028 
1029 static void
1030 udp6_close(struct socket *so)
1031 {
1032 	struct inpcb *inp;
1033 	struct inpcbinfo *pcbinfo;
1034 
1035 	pcbinfo = udp_get_inpcbinfo(so->so_proto->pr_protocol);
1036 	inp = sotoinpcb(so);
1037 	KASSERT(inp != NULL, ("udp6_close: inp == NULL"));
1038 
1039 #ifdef INET
1040 	if (inp->inp_vflag & INP_IPV4) {
1041 		struct pr_usrreqs *pru;
1042 
1043 		pru = inetsw[ip_protox[IPPROTO_UDP]].pr_usrreqs;
1044 		(*pru->pru_disconnect)(so);
1045 		return;
1046 	}
1047 #endif
1048 	INP_WLOCK(inp);
1049 	if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
1050 		INP_HASH_WLOCK(pcbinfo);
1051 		in6_pcbdisconnect(inp);
1052 		inp->in6p_laddr = in6addr_any;
1053 		INP_HASH_WUNLOCK(pcbinfo);
1054 		soisdisconnected(so);
1055 	}
1056 	INP_WUNLOCK(inp);
1057 }
1058 
1059 static int
1060 udp6_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
1061 {
1062 	struct inpcb *inp;
1063 	struct inpcbinfo *pcbinfo;
1064 	struct sockaddr_in6 *sin6;
1065 	int error;
1066 
1067 	pcbinfo = udp_get_inpcbinfo(so->so_proto->pr_protocol);
1068 	inp = sotoinpcb(so);
1069 	sin6 = (struct sockaddr_in6 *)nam;
1070 	KASSERT(inp != NULL, ("udp6_connect: inp == NULL"));
1071 
1072 	/*
1073 	 * XXXRW: Need to clarify locking of v4/v6 flags.
1074 	 */
1075 	INP_WLOCK(inp);
1076 #ifdef INET
1077 	if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) {
1078 		struct sockaddr_in sin;
1079 
1080 		if ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0) {
1081 			error = EINVAL;
1082 			goto out;
1083 		}
1084 		if (inp->inp_faddr.s_addr != INADDR_ANY) {
1085 			error = EISCONN;
1086 			goto out;
1087 		}
1088 		in6_sin6_2_sin(&sin, sin6);
1089 		inp->inp_vflag |= INP_IPV4;
1090 		inp->inp_vflag &= ~INP_IPV6;
1091 		error = prison_remote_ip4(td->td_ucred, &sin.sin_addr);
1092 		if (error != 0)
1093 			goto out;
1094 		INP_HASH_WLOCK(pcbinfo);
1095 		error = in_pcbconnect(inp, (struct sockaddr *)&sin,
1096 		    td->td_ucred);
1097 		INP_HASH_WUNLOCK(pcbinfo);
1098 		if (error == 0)
1099 			soisconnected(so);
1100 		goto out;
1101 	}
1102 #endif
1103 	if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
1104 		error = EISCONN;
1105 		goto out;
1106 	}
1107 	inp->inp_vflag &= ~INP_IPV4;
1108 	inp->inp_vflag |= INP_IPV6;
1109 	error = prison_remote_ip6(td->td_ucred, &sin6->sin6_addr);
1110 	if (error != 0)
1111 		goto out;
1112 	INP_HASH_WLOCK(pcbinfo);
1113 	error = in6_pcbconnect(inp, nam, td->td_ucred);
1114 	INP_HASH_WUNLOCK(pcbinfo);
1115 	if (error == 0)
1116 		soisconnected(so);
1117 out:
1118 	INP_WUNLOCK(inp);
1119 	return (error);
1120 }
1121 
1122 static void
1123 udp6_detach(struct socket *so)
1124 {
1125 	struct inpcb *inp;
1126 	struct inpcbinfo *pcbinfo;
1127 	struct udpcb *up;
1128 
1129 	pcbinfo = udp_get_inpcbinfo(so->so_proto->pr_protocol);
1130 	inp = sotoinpcb(so);
1131 	KASSERT(inp != NULL, ("udp6_detach: inp == NULL"));
1132 
1133 	INP_INFO_WLOCK(pcbinfo);
1134 	INP_WLOCK(inp);
1135 	up = intoudpcb(inp);
1136 	KASSERT(up != NULL, ("%s: up == NULL", __func__));
1137 	in_pcbdetach(inp);
1138 	in_pcbfree(inp);
1139 	INP_INFO_WUNLOCK(pcbinfo);
1140 	udp_discardcb(up);
1141 }
1142 
1143 static int
1144 udp6_disconnect(struct socket *so)
1145 {
1146 	struct inpcb *inp;
1147 	struct inpcbinfo *pcbinfo;
1148 	int error;
1149 
1150 	pcbinfo = udp_get_inpcbinfo(so->so_proto->pr_protocol);
1151 	inp = sotoinpcb(so);
1152 	KASSERT(inp != NULL, ("udp6_disconnect: inp == NULL"));
1153 
1154 #ifdef INET
1155 	if (inp->inp_vflag & INP_IPV4) {
1156 		struct pr_usrreqs *pru;
1157 
1158 		pru = inetsw[ip_protox[IPPROTO_UDP]].pr_usrreqs;
1159 		(void)(*pru->pru_disconnect)(so);
1160 		return (0);
1161 	}
1162 #endif
1163 
1164 	INP_WLOCK(inp);
1165 
1166 	if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
1167 		error = ENOTCONN;
1168 		goto out;
1169 	}
1170 
1171 	INP_HASH_WLOCK(pcbinfo);
1172 	in6_pcbdisconnect(inp);
1173 	inp->in6p_laddr = in6addr_any;
1174 	INP_HASH_WUNLOCK(pcbinfo);
1175 	SOCK_LOCK(so);
1176 	so->so_state &= ~SS_ISCONNECTED;		/* XXX */
1177 	SOCK_UNLOCK(so);
1178 out:
1179 	INP_WUNLOCK(inp);
1180 	return (0);
1181 }
1182 
1183 static int
1184 udp6_send(struct socket *so, int flags, struct mbuf *m,
1185     struct sockaddr *addr, struct mbuf *control, struct thread *td)
1186 {
1187 	struct inpcb *inp;
1188 	struct inpcbinfo *pcbinfo;
1189 	int error = 0;
1190 
1191 	pcbinfo = udp_get_inpcbinfo(so->so_proto->pr_protocol);
1192 	inp = sotoinpcb(so);
1193 	KASSERT(inp != NULL, ("udp6_send: inp == NULL"));
1194 
1195 	INP_WLOCK(inp);
1196 	if (addr) {
1197 		if (addr->sa_len != sizeof(struct sockaddr_in6)) {
1198 			error = EINVAL;
1199 			goto bad;
1200 		}
1201 		if (addr->sa_family != AF_INET6) {
1202 			error = EAFNOSUPPORT;
1203 			goto bad;
1204 		}
1205 	}
1206 
1207 #ifdef INET
1208 	if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0) {
1209 		int hasv4addr;
1210 		struct sockaddr_in6 *sin6 = 0;
1211 
1212 		if (addr == 0)
1213 			hasv4addr = (inp->inp_vflag & INP_IPV4);
1214 		else {
1215 			sin6 = (struct sockaddr_in6 *)addr;
1216 			hasv4addr = IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)
1217 			    ? 1 : 0;
1218 		}
1219 		if (hasv4addr) {
1220 			struct pr_usrreqs *pru;
1221 
1222 			/*
1223 			 * XXXRW: We release UDP-layer locks before calling
1224 			 * udp_send() in order to avoid recursion.  However,
1225 			 * this does mean there is a short window where inp's
1226 			 * fields are unstable.  Could this lead to a
1227 			 * potential race in which the factors causing us to
1228 			 * select the UDPv4 output routine are invalidated?
1229 			 */
1230 			INP_WUNLOCK(inp);
1231 			if (sin6)
1232 				in6_sin6_2_sin_in_sock(addr);
1233 			pru = inetsw[ip_protox[IPPROTO_UDP]].pr_usrreqs;
1234 			/* addr will just be freed in sendit(). */
1235 			return ((*pru->pru_send)(so, flags, m, addr, control,
1236 			    td));
1237 		}
1238 	}
1239 #endif
1240 #ifdef MAC
1241 	mac_inpcb_create_mbuf(inp, m);
1242 #endif
1243 	INP_HASH_WLOCK(pcbinfo);
1244 	error = udp6_output(inp, m, addr, control, td);
1245 	INP_HASH_WUNLOCK(pcbinfo);
1246 	INP_WUNLOCK(inp);
1247 	return (error);
1248 
1249 bad:
1250 	INP_WUNLOCK(inp);
1251 	m_freem(m);
1252 	return (error);
1253 }
1254 
1255 struct pr_usrreqs udp6_usrreqs = {
1256 	.pru_abort =		udp6_abort,
1257 	.pru_attach =		udp6_attach,
1258 	.pru_bind =		udp6_bind,
1259 	.pru_connect =		udp6_connect,
1260 	.pru_control =		in6_control,
1261 	.pru_detach =		udp6_detach,
1262 	.pru_disconnect =	udp6_disconnect,
1263 	.pru_peeraddr =		in6_mapped_peeraddr,
1264 	.pru_send =		udp6_send,
1265 	.pru_shutdown =		udp_shutdown,
1266 	.pru_sockaddr =		in6_mapped_sockaddr,
1267 	.pru_soreceive =	soreceive_dgram,
1268 	.pru_sosend =		sosend_dgram,
1269 	.pru_sosetlabel =	in_pcbsosetlabel,
1270 	.pru_close =		udp6_close
1271 };
1272