udp6_usrreq.c revision 319411
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: stable/11/sys/netinet6/udp6_usrreq.c 319411 2017-06-01 10:03:41Z tuexen $");
72
73#include "opt_inet.h"
74#include "opt_inet6.h"
75#include "opt_ipsec.h"
76#include "opt_rss.h"
77
78#include <sys/param.h>
79#include <sys/jail.h>
80#include <sys/kernel.h>
81#include <sys/lock.h>
82#include <sys/mbuf.h>
83#include <sys/priv.h>
84#include <sys/proc.h>
85#include <sys/protosw.h>
86#include <sys/sdt.h>
87#include <sys/signalvar.h>
88#include <sys/socket.h>
89#include <sys/socketvar.h>
90#include <sys/sx.h>
91#include <sys/sysctl.h>
92#include <sys/syslog.h>
93#include <sys/systm.h>
94
95#include <net/if.h>
96#include <net/if_var.h>
97#include <net/if_types.h>
98#include <net/route.h>
99#include <net/rss_config.h>
100
101#include <netinet/in.h>
102#include <netinet/in_kdtrace.h>
103#include <netinet/in_pcb.h>
104#include <netinet/in_systm.h>
105#include <netinet/in_var.h>
106#include <netinet/ip.h>
107#include <netinet/ip_icmp.h>
108#include <netinet/ip6.h>
109#include <netinet/icmp_var.h>
110#include <netinet/icmp6.h>
111#include <netinet/ip_var.h>
112#include <netinet/udp.h>
113#include <netinet/udp_var.h>
114#include <netinet/udplite.h>
115
116#include <netinet6/ip6protosw.h>
117#include <netinet6/ip6_var.h>
118#include <netinet6/in6_pcb.h>
119#include <netinet6/in6_rss.h>
120#include <netinet6/udp6_var.h>
121#include <netinet6/scope6_var.h>
122
123#include <netipsec/ipsec_support.h>
124
125#include <security/mac/mac_framework.h>
126
127/*
128 * UDP protocol implementation.
129 * Per RFC 768, August, 1980.
130 */
131
132extern struct protosw	inetsw[];
133static void		udp6_detach(struct socket *so);
134
135static int
136udp6_append(struct inpcb *inp, struct mbuf *n, int off,
137    struct sockaddr_in6 *fromsa)
138{
139	struct socket *so;
140	struct mbuf *opts;
141	struct udpcb *up;
142
143	INP_LOCK_ASSERT(inp);
144
145	/*
146	 * Engage the tunneling protocol.
147	 */
148	up = intoudpcb(inp);
149	if (up->u_tun_func != NULL) {
150		in_pcbref(inp);
151		INP_RUNLOCK(inp);
152		(*up->u_tun_func)(n, off, inp, (struct sockaddr *)fromsa,
153		    up->u_tun_ctx);
154		INP_RLOCK(inp);
155		return (in_pcbrele_rlocked(inp));
156	}
157#if defined(IPSEC) || defined(IPSEC_SUPPORT)
158	/* Check AH/ESP integrity. */
159	if (IPSEC_ENABLED(ipv6)) {
160		if (IPSEC_CHECK_POLICY(ipv6, n, inp) != 0) {
161			m_freem(n);
162			return (0);
163		}
164	}
165#endif /* IPSEC */
166#ifdef MAC
167	if (mac_inpcb_check_deliver(inp, n) != 0) {
168		m_freem(n);
169		return (0);
170	}
171#endif
172	opts = NULL;
173	if (inp->inp_flags & INP_CONTROLOPTS ||
174	    inp->inp_socket->so_options & SO_TIMESTAMP)
175		ip6_savecontrol(inp, n, &opts);
176	m_adj(n, off + sizeof(struct udphdr));
177
178	so = inp->inp_socket;
179	SOCKBUF_LOCK(&so->so_rcv);
180	if (sbappendaddr_locked(&so->so_rcv, (struct sockaddr *)fromsa, n,
181	    opts) == 0) {
182		SOCKBUF_UNLOCK(&so->so_rcv);
183		m_freem(n);
184		if (opts)
185			m_freem(opts);
186		UDPSTAT_INC(udps_fullsock);
187	} else
188		sorwakeup_locked(so);
189	return (0);
190}
191
192int
193udp6_input(struct mbuf **mp, int *offp, int proto)
194{
195	struct mbuf *m = *mp;
196	struct ifnet *ifp;
197	struct ip6_hdr *ip6;
198	struct udphdr *uh;
199	struct inpcb *inp;
200	struct inpcbinfo *pcbinfo;
201	struct udpcb *up;
202	int off = *offp;
203	int cscov_partial;
204	int plen, ulen;
205	struct sockaddr_in6 fromsa;
206	struct m_tag *fwd_tag;
207	uint16_t uh_sum;
208	uint8_t nxt;
209
210	ifp = m->m_pkthdr.rcvif;
211	ip6 = mtod(m, struct ip6_hdr *);
212
213#ifndef PULLDOWN_TEST
214	IP6_EXTHDR_CHECK(m, off, sizeof(struct udphdr), IPPROTO_DONE);
215	ip6 = mtod(m, struct ip6_hdr *);
216	uh = (struct udphdr *)((caddr_t)ip6 + off);
217#else
218	IP6_EXTHDR_GET(uh, struct udphdr *, m, off, sizeof(*uh));
219	if (!uh)
220		return (IPPROTO_DONE);
221#endif
222
223	UDPSTAT_INC(udps_ipackets);
224
225	/*
226	 * Destination port of 0 is illegal, based on RFC768.
227	 */
228	if (uh->uh_dport == 0)
229		goto badunlocked;
230
231	plen = ntohs(ip6->ip6_plen) - off + sizeof(*ip6);
232	ulen = ntohs((u_short)uh->uh_ulen);
233
234	nxt = proto;
235	cscov_partial = (nxt == IPPROTO_UDPLITE) ? 1 : 0;
236	if (nxt == IPPROTO_UDPLITE) {
237		/* Zero means checksum over the complete packet. */
238		if (ulen == 0)
239			ulen = plen;
240		if (ulen == plen)
241			cscov_partial = 0;
242		if ((ulen < sizeof(struct udphdr)) || (ulen > plen)) {
243			/* XXX: What is the right UDPLite MIB counter? */
244			goto badunlocked;
245		}
246		if (uh->uh_sum == 0) {
247			/* XXX: What is the right UDPLite MIB counter? */
248			goto badunlocked;
249		}
250	} else {
251		if ((ulen < sizeof(struct udphdr)) || (plen != ulen)) {
252			UDPSTAT_INC(udps_badlen);
253			goto badunlocked;
254		}
255		if (uh->uh_sum == 0) {
256			UDPSTAT_INC(udps_nosum);
257			goto badunlocked;
258		}
259	}
260
261	if ((m->m_pkthdr.csum_flags & CSUM_DATA_VALID_IPV6) &&
262	    !cscov_partial) {
263		if (m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR)
264			uh_sum = m->m_pkthdr.csum_data;
265		else
266			uh_sum = in6_cksum_pseudo(ip6, ulen, nxt,
267			    m->m_pkthdr.csum_data);
268		uh_sum ^= 0xffff;
269	} else
270		uh_sum = in6_cksum_partial(m, nxt, off, plen, ulen);
271
272	if (uh_sum != 0) {
273		UDPSTAT_INC(udps_badsum);
274		goto badunlocked;
275	}
276
277	/*
278	 * Construct sockaddr format source address.
279	 */
280	init_sin6(&fromsa, m);
281	fromsa.sin6_port = uh->uh_sport;
282
283	pcbinfo = udp_get_inpcbinfo(nxt);
284	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
285		struct inpcb *last;
286		struct inpcbhead *pcblist;
287		struct ip6_moptions *imo;
288
289		INP_INFO_RLOCK(pcbinfo);
290		/*
291		 * In the event that laddr should be set to the link-local
292		 * address (this happens in RIPng), the multicast address
293		 * specified in the received packet will not match laddr.  To
294		 * handle this situation, matching is relaxed if the
295		 * receiving interface is the same as one specified in the
296		 * socket and if the destination multicast address matches
297		 * one of the multicast groups specified in the socket.
298		 */
299
300		/*
301		 * KAME note: traditionally we dropped udpiphdr from mbuf
302		 * here.  We need udphdr for IPsec processing so we do that
303		 * later.
304		 */
305		pcblist = udp_get_pcblist(nxt);
306		last = NULL;
307		LIST_FOREACH(inp, pcblist, inp_list) {
308			if ((inp->inp_vflag & INP_IPV6) == 0)
309				continue;
310			if (inp->inp_lport != uh->uh_dport)
311				continue;
312			if (inp->inp_fport != 0 &&
313			    inp->inp_fport != uh->uh_sport)
314				continue;
315			if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr)) {
316				if (!IN6_ARE_ADDR_EQUAL(&inp->in6p_laddr,
317							&ip6->ip6_dst))
318					continue;
319			}
320			if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
321				if (!IN6_ARE_ADDR_EQUAL(&inp->in6p_faddr,
322							&ip6->ip6_src) ||
323				    inp->inp_fport != uh->uh_sport)
324					continue;
325			}
326
327			/*
328			 * XXXRW: Because we weren't holding either the inpcb
329			 * or the hash lock when we checked for a match
330			 * before, we should probably recheck now that the
331			 * inpcb lock is (supposed to be) held.
332			 */
333
334			/*
335			 * Handle socket delivery policy for any-source
336			 * and source-specific multicast. [RFC3678]
337			 */
338			imo = inp->in6p_moptions;
339			if (imo && IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
340				struct sockaddr_in6	 mcaddr;
341				int			 blocked;
342
343				INP_RLOCK(inp);
344
345				bzero(&mcaddr, sizeof(struct sockaddr_in6));
346				mcaddr.sin6_len = sizeof(struct sockaddr_in6);
347				mcaddr.sin6_family = AF_INET6;
348				mcaddr.sin6_addr = ip6->ip6_dst;
349
350				blocked = im6o_mc_filter(imo, ifp,
351					(struct sockaddr *)&mcaddr,
352					(struct sockaddr *)&fromsa);
353				if (blocked != MCAST_PASS) {
354					if (blocked == MCAST_NOTGMEMBER)
355						IP6STAT_INC(ip6s_notmember);
356					if (blocked == MCAST_NOTSMEMBER ||
357					    blocked == MCAST_MUTED)
358						UDPSTAT_INC(udps_filtermcast);
359					INP_RUNLOCK(inp); /* XXX */
360					continue;
361				}
362
363				INP_RUNLOCK(inp);
364			}
365			if (last != NULL) {
366				struct mbuf *n;
367
368				if ((n = m_copy(m, 0, M_COPYALL)) != NULL) {
369					INP_RLOCK(last);
370					UDP_PROBE(receive, NULL, last, ip6,
371					    last, uh);
372					if (udp6_append(last, n, off, &fromsa))
373						goto inp_lost;
374					INP_RUNLOCK(last);
375				}
376			}
377			last = inp;
378			/*
379			 * Don't look for additional matches if this one does
380			 * not have either the SO_REUSEPORT or SO_REUSEADDR
381			 * socket options set.  This heuristic avoids
382			 * searching through all pcbs in the common case of a
383			 * non-shared port.  It assumes that an application
384			 * will never clear these options after setting them.
385			 */
386			if ((last->inp_socket->so_options &
387			     (SO_REUSEPORT|SO_REUSEADDR)) == 0)
388				break;
389		}
390
391		if (last == NULL) {
392			/*
393			 * No matching pcb found; discard datagram.  (No need
394			 * to send an ICMP Port Unreachable for a broadcast
395			 * or multicast datgram.)
396			 */
397			UDPSTAT_INC(udps_noport);
398			UDPSTAT_INC(udps_noportmcast);
399			goto badheadlocked;
400		}
401		INP_RLOCK(last);
402		INP_INFO_RUNLOCK(pcbinfo);
403		UDP_PROBE(receive, NULL, last, ip6, last, uh);
404		if (udp6_append(last, m, off, &fromsa) == 0)
405			INP_RUNLOCK(last);
406	inp_lost:
407		return (IPPROTO_DONE);
408	}
409	/*
410	 * Locate pcb for datagram.
411	 */
412
413	/*
414	 * Grab info from PACKET_TAG_IPFORWARD tag prepended to the chain.
415	 */
416	if ((m->m_flags & M_IP6_NEXTHOP) &&
417	    (fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL)) != NULL) {
418		struct sockaddr_in6 *next_hop6;
419
420		next_hop6 = (struct sockaddr_in6 *)(fwd_tag + 1);
421
422		/*
423		 * Transparently forwarded. Pretend to be the destination.
424		 * Already got one like this?
425		 */
426		inp = in6_pcblookup_mbuf(pcbinfo, &ip6->ip6_src,
427		    uh->uh_sport, &ip6->ip6_dst, uh->uh_dport,
428		    INPLOOKUP_RLOCKPCB, m->m_pkthdr.rcvif, m);
429		if (!inp) {
430			/*
431			 * It's new.  Try to find the ambushing socket.
432			 * Because we've rewritten the destination address,
433			 * any hardware-generated hash is ignored.
434			 */
435			inp = in6_pcblookup(pcbinfo, &ip6->ip6_src,
436			    uh->uh_sport, &next_hop6->sin6_addr,
437			    next_hop6->sin6_port ? htons(next_hop6->sin6_port) :
438			    uh->uh_dport, INPLOOKUP_WILDCARD |
439			    INPLOOKUP_RLOCKPCB, m->m_pkthdr.rcvif);
440		}
441		/* Remove the tag from the packet. We don't need it anymore. */
442		m_tag_delete(m, fwd_tag);
443		m->m_flags &= ~M_IP6_NEXTHOP;
444	} else
445		inp = in6_pcblookup_mbuf(pcbinfo, &ip6->ip6_src,
446		    uh->uh_sport, &ip6->ip6_dst, uh->uh_dport,
447		    INPLOOKUP_WILDCARD | INPLOOKUP_RLOCKPCB,
448		    m->m_pkthdr.rcvif, m);
449	if (inp == NULL) {
450		if (udp_log_in_vain) {
451			char ip6bufs[INET6_ADDRSTRLEN];
452			char ip6bufd[INET6_ADDRSTRLEN];
453
454			log(LOG_INFO,
455			    "Connection attempt to UDP [%s]:%d from [%s]:%d\n",
456			    ip6_sprintf(ip6bufd, &ip6->ip6_dst),
457			    ntohs(uh->uh_dport),
458			    ip6_sprintf(ip6bufs, &ip6->ip6_src),
459			    ntohs(uh->uh_sport));
460		}
461		UDPSTAT_INC(udps_noport);
462		if (m->m_flags & M_MCAST) {
463			printf("UDP6: M_MCAST is set in a unicast packet.\n");
464			UDPSTAT_INC(udps_noportmcast);
465			goto badunlocked;
466		}
467		if (V_udp_blackhole)
468			goto badunlocked;
469		if (badport_bandlim(BANDLIM_ICMP6_UNREACH) < 0)
470			goto badunlocked;
471		icmp6_error(m, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOPORT, 0);
472		return (IPPROTO_DONE);
473	}
474	INP_RLOCK_ASSERT(inp);
475	up = intoudpcb(inp);
476	if (cscov_partial) {
477		if (up->u_rxcslen == 0 || up->u_rxcslen > ulen) {
478			INP_RUNLOCK(inp);
479			m_freem(m);
480			return (IPPROTO_DONE);
481		}
482	}
483	UDP_PROBE(receive, NULL, inp, ip6, inp, uh);
484	if (udp6_append(inp, m, off, &fromsa) == 0)
485		INP_RUNLOCK(inp);
486	return (IPPROTO_DONE);
487
488badheadlocked:
489	INP_INFO_RUNLOCK(pcbinfo);
490badunlocked:
491	if (m)
492		m_freem(m);
493	return (IPPROTO_DONE);
494}
495
496static void
497udp6_common_ctlinput(int cmd, struct sockaddr *sa, void *d,
498    struct inpcbinfo *pcbinfo)
499{
500	struct udphdr uh;
501	struct ip6_hdr *ip6;
502	struct mbuf *m;
503	int off = 0;
504	struct ip6ctlparam *ip6cp = NULL;
505	const struct sockaddr_in6 *sa6_src = NULL;
506	void *cmdarg;
507	struct inpcb *(*notify)(struct inpcb *, int) = udp_notify;
508	struct udp_portonly {
509		u_int16_t uh_sport;
510		u_int16_t uh_dport;
511	} *uhp;
512
513	if (sa->sa_family != AF_INET6 ||
514	    sa->sa_len != sizeof(struct sockaddr_in6))
515		return;
516
517	if ((unsigned)cmd >= PRC_NCMDS)
518		return;
519	if (PRC_IS_REDIRECT(cmd))
520		notify = in6_rtchange, d = NULL;
521	else if (cmd == PRC_HOSTDEAD)
522		d = NULL;
523	else if (inet6ctlerrmap[cmd] == 0)
524		return;
525
526	/* if the parameter is from icmp6, decode it. */
527	if (d != NULL) {
528		ip6cp = (struct ip6ctlparam *)d;
529		m = ip6cp->ip6c_m;
530		ip6 = ip6cp->ip6c_ip6;
531		off = ip6cp->ip6c_off;
532		cmdarg = ip6cp->ip6c_cmdarg;
533		sa6_src = ip6cp->ip6c_src;
534	} else {
535		m = NULL;
536		ip6 = NULL;
537		cmdarg = NULL;
538		sa6_src = &sa6_any;
539	}
540
541	if (ip6) {
542		/*
543		 * XXX: We assume that when IPV6 is non NULL,
544		 * M and OFF are valid.
545		 */
546
547		/* Check if we can safely examine src and dst ports. */
548		if (m->m_pkthdr.len < off + sizeof(*uhp))
549			return;
550
551		bzero(&uh, sizeof(uh));
552		m_copydata(m, off, sizeof(*uhp), (caddr_t)&uh);
553
554		if (!PRC_IS_REDIRECT(cmd)) {
555			/* Check to see if its tunneled */
556			struct inpcb *inp;
557			inp = in6_pcblookup_mbuf(pcbinfo, &ip6->ip6_dst,
558			    uh.uh_dport, &ip6->ip6_src, uh.uh_sport,
559			    INPLOOKUP_WILDCARD | INPLOOKUP_RLOCKPCB,
560			    m->m_pkthdr.rcvif, m);
561			if (inp != NULL) {
562				struct udpcb *up;
563
564				up = intoudpcb(inp);
565				if (up->u_icmp_func) {
566					/* Yes it is. */
567					INP_RUNLOCK(inp);
568					(*up->u_icmp_func)(cmd, (struct sockaddr *)ip6cp->ip6c_src,
569					      d, up->u_tun_ctx);
570					return;
571				} else {
572					/* Can't find it. */
573					INP_RUNLOCK(inp);
574				}
575			}
576		}
577		(void)in6_pcbnotify(pcbinfo, sa, uh.uh_dport,
578		    (struct sockaddr *)ip6cp->ip6c_src, uh.uh_sport, cmd,
579		    cmdarg, notify);
580	} else
581		(void)in6_pcbnotify(pcbinfo, sa, 0,
582		    (const struct sockaddr *)sa6_src, 0, cmd, cmdarg, notify);
583}
584
585void
586udp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
587{
588
589	return (udp6_common_ctlinput(cmd, sa, d, &V_udbinfo));
590}
591
592void
593udplite6_ctlinput(int cmd, struct sockaddr *sa, void *d)
594{
595
596	return (udp6_common_ctlinput(cmd, sa, d, &V_ulitecbinfo));
597}
598
599static int
600udp6_getcred(SYSCTL_HANDLER_ARGS)
601{
602	struct xucred xuc;
603	struct sockaddr_in6 addrs[2];
604	struct inpcb *inp;
605	int error;
606
607	error = priv_check(req->td, PRIV_NETINET_GETCRED);
608	if (error)
609		return (error);
610
611	if (req->newlen != sizeof(addrs))
612		return (EINVAL);
613	if (req->oldlen != sizeof(struct xucred))
614		return (EINVAL);
615	error = SYSCTL_IN(req, addrs, sizeof(addrs));
616	if (error)
617		return (error);
618	if ((error = sa6_embedscope(&addrs[0], V_ip6_use_defzone)) != 0 ||
619	    (error = sa6_embedscope(&addrs[1], V_ip6_use_defzone)) != 0) {
620		return (error);
621	}
622	inp = in6_pcblookup(&V_udbinfo, &addrs[1].sin6_addr,
623	    addrs[1].sin6_port, &addrs[0].sin6_addr, addrs[0].sin6_port,
624	    INPLOOKUP_WILDCARD | INPLOOKUP_RLOCKPCB, NULL);
625	if (inp != NULL) {
626		INP_RLOCK_ASSERT(inp);
627		if (inp->inp_socket == NULL)
628			error = ENOENT;
629		if (error == 0)
630			error = cr_canseesocket(req->td->td_ucred,
631			    inp->inp_socket);
632		if (error == 0)
633			cru2x(inp->inp_cred, &xuc);
634		INP_RUNLOCK(inp);
635	} else
636		error = ENOENT;
637	if (error == 0)
638		error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
639	return (error);
640}
641
642SYSCTL_PROC(_net_inet6_udp6, OID_AUTO, getcred, CTLTYPE_OPAQUE|CTLFLAG_RW, 0,
643    0, udp6_getcred, "S,xucred", "Get the xucred of a UDP6 connection");
644
645static int
646udp6_output(struct inpcb *inp, struct mbuf *m, struct sockaddr *addr6,
647    struct mbuf *control, struct thread *td)
648{
649	u_int32_t ulen = m->m_pkthdr.len;
650	u_int32_t plen = sizeof(struct udphdr) + ulen;
651	struct ip6_hdr *ip6;
652	struct udphdr *udp6;
653	struct in6_addr *laddr, *faddr, in6a;
654	struct sockaddr_in6 *sin6 = NULL;
655	int cscov_partial = 0;
656	int scope_ambiguous = 0;
657	u_short fport;
658	int error = 0;
659	uint8_t nxt;
660	uint16_t cscov = 0;
661	struct ip6_pktopts *optp, opt;
662	int af = AF_INET6, hlen = sizeof(struct ip6_hdr);
663	int flags;
664	struct sockaddr_in6 tmp;
665
666	INP_WLOCK_ASSERT(inp);
667	INP_HASH_WLOCK_ASSERT(inp->inp_pcbinfo);
668
669	if (addr6) {
670		/* addr6 has been validated in udp6_send(). */
671		sin6 = (struct sockaddr_in6 *)addr6;
672
673		/* protect *sin6 from overwrites */
674		tmp = *sin6;
675		sin6 = &tmp;
676
677		/*
678		 * Application should provide a proper zone ID or the use of
679		 * default zone IDs should be enabled.  Unfortunately, some
680		 * applications do not behave as it should, so we need a
681		 * workaround.  Even if an appropriate ID is not determined,
682		 * we'll see if we can determine the outgoing interface.  If we
683		 * can, determine the zone ID based on the interface below.
684		 */
685		if (sin6->sin6_scope_id == 0 && !V_ip6_use_defzone)
686			scope_ambiguous = 1;
687		if ((error = sa6_embedscope(sin6, V_ip6_use_defzone)) != 0)
688			return (error);
689	}
690
691	nxt = (inp->inp_socket->so_proto->pr_protocol == IPPROTO_UDP) ?
692	    IPPROTO_UDP : IPPROTO_UDPLITE;
693	if (control) {
694		if ((error = ip6_setpktopts(control, &opt,
695		    inp->in6p_outputopts, td->td_ucred, nxt)) != 0)
696			goto release;
697		optp = &opt;
698	} else
699		optp = inp->in6p_outputopts;
700
701	if (sin6) {
702		faddr = &sin6->sin6_addr;
703
704		/*
705		 * Since we saw no essential reason for calling in_pcbconnect,
706		 * we get rid of such kind of logic, and call in6_selectsrc
707		 * and in6_pcbsetport in order to fill in the local address
708		 * and the local port.
709		 */
710		if (sin6->sin6_port == 0) {
711			error = EADDRNOTAVAIL;
712			goto release;
713		}
714
715		if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
716			/* how about ::ffff:0.0.0.0 case? */
717			error = EISCONN;
718			goto release;
719		}
720
721		fport = sin6->sin6_port; /* allow 0 port */
722
723		if (IN6_IS_ADDR_V4MAPPED(faddr)) {
724			if ((inp->inp_flags & IN6P_IPV6_V6ONLY)) {
725				/*
726				 * I believe we should explicitly discard the
727				 * packet when mapped addresses are disabled,
728				 * rather than send the packet as an IPv6 one.
729				 * If we chose the latter approach, the packet
730				 * might be sent out on the wire based on the
731				 * default route, the situation which we'd
732				 * probably want to avoid.
733				 * (20010421 jinmei@kame.net)
734				 */
735				error = EINVAL;
736				goto release;
737			}
738			if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr) &&
739			    !IN6_IS_ADDR_V4MAPPED(&inp->in6p_laddr)) {
740				/*
741				 * when remote addr is an IPv4-mapped address,
742				 * local addr should not be an IPv6 address,
743				 * since you cannot determine how to map IPv6
744				 * source address to IPv4.
745				 */
746				error = EINVAL;
747				goto release;
748			}
749
750			af = AF_INET;
751		}
752
753		if (!IN6_IS_ADDR_V4MAPPED(faddr)) {
754			error = in6_selectsrc_socket(sin6, optp, inp,
755			    td->td_ucred, scope_ambiguous, &in6a, NULL);
756			if (error)
757				goto release;
758			laddr = &in6a;
759		} else
760			laddr = &inp->in6p_laddr;	/* XXX */
761		if (laddr == NULL) {
762			if (error == 0)
763				error = EADDRNOTAVAIL;
764			goto release;
765		}
766		if (inp->inp_lport == 0 &&
767		    (error = in6_pcbsetport(laddr, inp, td->td_ucred)) != 0) {
768			/* Undo an address bind that may have occurred. */
769			inp->in6p_laddr = in6addr_any;
770			goto release;
771		}
772	} else {
773		if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
774			error = ENOTCONN;
775			goto release;
776		}
777		if (IN6_IS_ADDR_V4MAPPED(&inp->in6p_faddr)) {
778			if ((inp->inp_flags & IN6P_IPV6_V6ONLY)) {
779				/*
780				 * XXX: this case would happen when the
781				 * application sets the V6ONLY flag after
782				 * connecting the foreign address.
783				 * Such applications should be fixed,
784				 * so we bark here.
785				 */
786				log(LOG_INFO, "udp6_output: IPV6_V6ONLY "
787				    "option was set for a connected socket\n");
788				error = EINVAL;
789				goto release;
790			} else
791				af = AF_INET;
792		}
793		laddr = &inp->in6p_laddr;
794		faddr = &inp->in6p_faddr;
795		fport = inp->inp_fport;
796	}
797
798	if (af == AF_INET)
799		hlen = sizeof(struct ip);
800
801	/*
802	 * Calculate data length and get a mbuf
803	 * for UDP and IP6 headers.
804	 */
805	M_PREPEND(m, hlen + sizeof(struct udphdr), M_NOWAIT);
806	if (m == NULL) {
807		error = ENOBUFS;
808		goto release;
809	}
810
811	/*
812	 * Stuff checksum and output datagram.
813	 */
814	udp6 = (struct udphdr *)(mtod(m, caddr_t) + hlen);
815	udp6->uh_sport = inp->inp_lport; /* lport is always set in the PCB */
816	udp6->uh_dport = fport;
817	if (nxt == IPPROTO_UDPLITE) {
818		struct udpcb *up;
819
820		up = intoudpcb(inp);
821		cscov = up->u_txcslen;
822		if (cscov >= plen)
823			cscov = 0;
824		udp6->uh_ulen = htons(cscov);
825		/*
826		 * For UDP-Lite, checksum coverage length of zero means
827		 * the entire UDPLite packet is covered by the checksum.
828		 */
829		cscov_partial = (cscov == 0) ? 0 : 1;
830	} else if (plen <= 0xffff)
831		udp6->uh_ulen = htons((u_short)plen);
832	else
833		udp6->uh_ulen = 0;
834	udp6->uh_sum = 0;
835
836	switch (af) {
837	case AF_INET6:
838		ip6 = mtod(m, struct ip6_hdr *);
839		ip6->ip6_flow	= inp->inp_flow & IPV6_FLOWINFO_MASK;
840		ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
841		ip6->ip6_vfc	|= IPV6_VERSION;
842		ip6->ip6_plen	= htons((u_short)plen);
843		ip6->ip6_nxt	= nxt;
844		ip6->ip6_hlim	= in6_selecthlim(inp, NULL);
845		ip6->ip6_src	= *laddr;
846		ip6->ip6_dst	= *faddr;
847
848		if (cscov_partial) {
849			if ((udp6->uh_sum = in6_cksum_partial(m, nxt,
850			    sizeof(struct ip6_hdr), plen, cscov)) == 0)
851				udp6->uh_sum = 0xffff;
852		} else {
853			udp6->uh_sum = in6_cksum_pseudo(ip6, plen, nxt, 0);
854			m->m_pkthdr.csum_flags = CSUM_UDP_IPV6;
855			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
856		}
857
858#ifdef	RSS
859		{
860			uint32_t hash_val, hash_type;
861			uint8_t pr;
862
863			pr = inp->inp_socket->so_proto->pr_protocol;
864			/*
865			 * Calculate an appropriate RSS hash for UDP and
866			 * UDP Lite.
867			 *
868			 * The called function will take care of figuring out
869			 * whether a 2-tuple or 4-tuple hash is required based
870			 * on the currently configured scheme.
871			 *
872			 * Later later on connected socket values should be
873			 * cached in the inpcb and reused, rather than constantly
874			 * re-calculating it.
875			 *
876			 * UDP Lite is a different protocol number and will
877			 * likely end up being hashed as a 2-tuple until
878			 * RSS / NICs grow UDP Lite protocol awareness.
879			 */
880			if (rss_proto_software_hash_v6(faddr, laddr, fport,
881			    inp->inp_lport, pr, &hash_val, &hash_type) == 0) {
882				m->m_pkthdr.flowid = hash_val;
883				M_HASHTYPE_SET(m, hash_type);
884			}
885		}
886#endif
887		flags = 0;
888#ifdef	RSS
889		/*
890		 * Don't override with the inp cached flowid.
891		 *
892		 * Until the whole UDP path is vetted, it may actually
893		 * be incorrect.
894		 */
895		flags |= IP_NODEFAULTFLOWID;
896#endif
897
898		UDP_PROBE(send, NULL, inp, ip6, inp, udp6);
899		UDPSTAT_INC(udps_opackets);
900		error = ip6_output(m, optp, &inp->inp_route6, flags,
901		    inp->in6p_moptions, NULL, inp);
902		break;
903	case AF_INET:
904		error = EAFNOSUPPORT;
905		goto release;
906	}
907	goto releaseopt;
908
909release:
910	m_freem(m);
911
912releaseopt:
913	if (control) {
914		ip6_clearpktopts(&opt, -1);
915		m_freem(control);
916	}
917	return (error);
918}
919
920static void
921udp6_abort(struct socket *so)
922{
923	struct inpcb *inp;
924	struct inpcbinfo *pcbinfo;
925
926	pcbinfo = udp_get_inpcbinfo(so->so_proto->pr_protocol);
927	inp = sotoinpcb(so);
928	KASSERT(inp != NULL, ("udp6_abort: inp == NULL"));
929
930	INP_WLOCK(inp);
931#ifdef INET
932	if (inp->inp_vflag & INP_IPV4) {
933		struct pr_usrreqs *pru;
934		uint8_t nxt;
935
936		nxt = (inp->inp_socket->so_proto->pr_protocol == IPPROTO_UDP) ?
937		    IPPROTO_UDP : IPPROTO_UDPLITE;
938		INP_WUNLOCK(inp);
939		pru = inetsw[ip_protox[nxt]].pr_usrreqs;
940		(*pru->pru_abort)(so);
941		return;
942	}
943#endif
944
945	if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
946		INP_HASH_WLOCK(pcbinfo);
947		in6_pcbdisconnect(inp);
948		inp->in6p_laddr = in6addr_any;
949		INP_HASH_WUNLOCK(pcbinfo);
950		soisdisconnected(so);
951	}
952	INP_WUNLOCK(inp);
953}
954
955static int
956udp6_attach(struct socket *so, int proto, struct thread *td)
957{
958	struct inpcb *inp;
959	struct inpcbinfo *pcbinfo;
960	int error;
961
962	pcbinfo = udp_get_inpcbinfo(so->so_proto->pr_protocol);
963	inp = sotoinpcb(so);
964	KASSERT(inp == NULL, ("udp6_attach: inp != NULL"));
965
966	if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
967		error = soreserve(so, udp_sendspace, udp_recvspace);
968		if (error)
969			return (error);
970	}
971	INP_INFO_WLOCK(pcbinfo);
972	error = in_pcballoc(so, pcbinfo);
973	if (error) {
974		INP_INFO_WUNLOCK(pcbinfo);
975		return (error);
976	}
977	inp = (struct inpcb *)so->so_pcb;
978	inp->inp_vflag |= INP_IPV6;
979	if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0)
980		inp->inp_vflag |= INP_IPV4;
981	inp->in6p_hops = -1;	/* use kernel default */
982	inp->in6p_cksum = -1;	/* just to be sure */
983	/*
984	 * XXX: ugly!!
985	 * IPv4 TTL initialization is necessary for an IPv6 socket as well,
986	 * because the socket may be bound to an IPv6 wildcard address,
987	 * which may match an IPv4-mapped IPv6 address.
988	 */
989	inp->inp_ip_ttl = V_ip_defttl;
990
991	error = udp_newudpcb(inp);
992	if (error) {
993		in_pcbdetach(inp);
994		in_pcbfree(inp);
995		INP_INFO_WUNLOCK(pcbinfo);
996		return (error);
997	}
998	INP_WUNLOCK(inp);
999	INP_INFO_WUNLOCK(pcbinfo);
1000	return (0);
1001}
1002
1003static int
1004udp6_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
1005{
1006	struct inpcb *inp;
1007	struct inpcbinfo *pcbinfo;
1008	int error;
1009
1010	pcbinfo = udp_get_inpcbinfo(so->so_proto->pr_protocol);
1011	inp = sotoinpcb(so);
1012	KASSERT(inp != NULL, ("udp6_bind: inp == NULL"));
1013
1014	INP_WLOCK(inp);
1015	INP_HASH_WLOCK(pcbinfo);
1016	inp->inp_vflag &= ~INP_IPV4;
1017	inp->inp_vflag |= INP_IPV6;
1018	if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0) {
1019		struct sockaddr_in6 *sin6_p;
1020
1021		sin6_p = (struct sockaddr_in6 *)nam;
1022
1023		if (IN6_IS_ADDR_UNSPECIFIED(&sin6_p->sin6_addr))
1024			inp->inp_vflag |= INP_IPV4;
1025#ifdef INET
1026		else if (IN6_IS_ADDR_V4MAPPED(&sin6_p->sin6_addr)) {
1027			struct sockaddr_in sin;
1028
1029			in6_sin6_2_sin(&sin, sin6_p);
1030			inp->inp_vflag |= INP_IPV4;
1031			inp->inp_vflag &= ~INP_IPV6;
1032			error = in_pcbbind(inp, (struct sockaddr *)&sin,
1033			    td->td_ucred);
1034			goto out;
1035		}
1036#endif
1037	}
1038
1039	error = in6_pcbbind(inp, nam, td->td_ucred);
1040#ifdef INET
1041out:
1042#endif
1043	INP_HASH_WUNLOCK(pcbinfo);
1044	INP_WUNLOCK(inp);
1045	return (error);
1046}
1047
1048static void
1049udp6_close(struct socket *so)
1050{
1051	struct inpcb *inp;
1052	struct inpcbinfo *pcbinfo;
1053
1054	pcbinfo = udp_get_inpcbinfo(so->so_proto->pr_protocol);
1055	inp = sotoinpcb(so);
1056	KASSERT(inp != NULL, ("udp6_close: inp == NULL"));
1057
1058	INP_WLOCK(inp);
1059#ifdef INET
1060	if (inp->inp_vflag & INP_IPV4) {
1061		struct pr_usrreqs *pru;
1062		uint8_t nxt;
1063
1064		nxt = (inp->inp_socket->so_proto->pr_protocol == IPPROTO_UDP) ?
1065		    IPPROTO_UDP : IPPROTO_UDPLITE;
1066		INP_WUNLOCK(inp);
1067		pru = inetsw[ip_protox[nxt]].pr_usrreqs;
1068		(*pru->pru_disconnect)(so);
1069		return;
1070	}
1071#endif
1072	if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
1073		INP_HASH_WLOCK(pcbinfo);
1074		in6_pcbdisconnect(inp);
1075		inp->in6p_laddr = in6addr_any;
1076		INP_HASH_WUNLOCK(pcbinfo);
1077		soisdisconnected(so);
1078	}
1079	INP_WUNLOCK(inp);
1080}
1081
1082static int
1083udp6_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
1084{
1085	struct inpcb *inp;
1086	struct inpcbinfo *pcbinfo;
1087	struct sockaddr_in6 *sin6;
1088	int error;
1089
1090	pcbinfo = udp_get_inpcbinfo(so->so_proto->pr_protocol);
1091	inp = sotoinpcb(so);
1092	sin6 = (struct sockaddr_in6 *)nam;
1093	KASSERT(inp != NULL, ("udp6_connect: inp == NULL"));
1094
1095	/*
1096	 * XXXRW: Need to clarify locking of v4/v6 flags.
1097	 */
1098	INP_WLOCK(inp);
1099#ifdef INET
1100	if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) {
1101		struct sockaddr_in sin;
1102
1103		if ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0) {
1104			error = EINVAL;
1105			goto out;
1106		}
1107		if ((inp->inp_vflag & INP_IPV4) == 0) {
1108			error = EAFNOSUPPORT;
1109			goto out;
1110		}
1111		if (inp->inp_faddr.s_addr != INADDR_ANY) {
1112			error = EISCONN;
1113			goto out;
1114		}
1115		in6_sin6_2_sin(&sin, sin6);
1116		inp->inp_vflag |= INP_IPV4;
1117		inp->inp_vflag &= ~INP_IPV6;
1118		error = prison_remote_ip4(td->td_ucred, &sin.sin_addr);
1119		if (error != 0)
1120			goto out;
1121		INP_HASH_WLOCK(pcbinfo);
1122		error = in_pcbconnect(inp, (struct sockaddr *)&sin,
1123		    td->td_ucred);
1124		INP_HASH_WUNLOCK(pcbinfo);
1125		if (error == 0)
1126			soisconnected(so);
1127		goto out;
1128	} else {
1129		if ((inp->inp_vflag & INP_IPV6) == 0) {
1130			error = EAFNOSUPPORT;
1131			goto out;
1132		}
1133	}
1134#endif
1135	if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
1136		error = EISCONN;
1137		goto out;
1138	}
1139	inp->inp_vflag &= ~INP_IPV4;
1140	inp->inp_vflag |= INP_IPV6;
1141	error = prison_remote_ip6(td->td_ucred, &sin6->sin6_addr);
1142	if (error != 0)
1143		goto out;
1144	INP_HASH_WLOCK(pcbinfo);
1145	error = in6_pcbconnect(inp, nam, td->td_ucred);
1146	INP_HASH_WUNLOCK(pcbinfo);
1147	if (error == 0)
1148		soisconnected(so);
1149out:
1150	INP_WUNLOCK(inp);
1151	return (error);
1152}
1153
1154static void
1155udp6_detach(struct socket *so)
1156{
1157	struct inpcb *inp;
1158	struct inpcbinfo *pcbinfo;
1159	struct udpcb *up;
1160
1161	pcbinfo = udp_get_inpcbinfo(so->so_proto->pr_protocol);
1162	inp = sotoinpcb(so);
1163	KASSERT(inp != NULL, ("udp6_detach: inp == NULL"));
1164
1165	INP_INFO_WLOCK(pcbinfo);
1166	INP_WLOCK(inp);
1167	up = intoudpcb(inp);
1168	KASSERT(up != NULL, ("%s: up == NULL", __func__));
1169	in_pcbdetach(inp);
1170	in_pcbfree(inp);
1171	INP_INFO_WUNLOCK(pcbinfo);
1172	udp_discardcb(up);
1173}
1174
1175static int
1176udp6_disconnect(struct socket *so)
1177{
1178	struct inpcb *inp;
1179	struct inpcbinfo *pcbinfo;
1180	int error;
1181
1182	pcbinfo = udp_get_inpcbinfo(so->so_proto->pr_protocol);
1183	inp = sotoinpcb(so);
1184	KASSERT(inp != NULL, ("udp6_disconnect: inp == NULL"));
1185
1186	INP_WLOCK(inp);
1187#ifdef INET
1188	if (inp->inp_vflag & INP_IPV4) {
1189		struct pr_usrreqs *pru;
1190		uint8_t nxt;
1191
1192		nxt = (inp->inp_socket->so_proto->pr_protocol == IPPROTO_UDP) ?
1193		    IPPROTO_UDP : IPPROTO_UDPLITE;
1194		INP_WUNLOCK(inp);
1195		pru = inetsw[ip_protox[nxt]].pr_usrreqs;
1196		(void)(*pru->pru_disconnect)(so);
1197		return (0);
1198	}
1199#endif
1200
1201	if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
1202		error = ENOTCONN;
1203		goto out;
1204	}
1205
1206	INP_HASH_WLOCK(pcbinfo);
1207	in6_pcbdisconnect(inp);
1208	inp->in6p_laddr = in6addr_any;
1209	INP_HASH_WUNLOCK(pcbinfo);
1210	SOCK_LOCK(so);
1211	so->so_state &= ~SS_ISCONNECTED;		/* XXX */
1212	SOCK_UNLOCK(so);
1213out:
1214	INP_WUNLOCK(inp);
1215	return (0);
1216}
1217
1218static int
1219udp6_send(struct socket *so, int flags, struct mbuf *m,
1220    struct sockaddr *addr, struct mbuf *control, struct thread *td)
1221{
1222	struct inpcb *inp;
1223	struct inpcbinfo *pcbinfo;
1224	int error = 0;
1225
1226	pcbinfo = udp_get_inpcbinfo(so->so_proto->pr_protocol);
1227	inp = sotoinpcb(so);
1228	KASSERT(inp != NULL, ("udp6_send: inp == NULL"));
1229
1230	INP_WLOCK(inp);
1231	if (addr) {
1232		if (addr->sa_len != sizeof(struct sockaddr_in6)) {
1233			error = EINVAL;
1234			goto bad;
1235		}
1236		if (addr->sa_family != AF_INET6) {
1237			error = EAFNOSUPPORT;
1238			goto bad;
1239		}
1240	}
1241
1242#ifdef INET
1243	if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0) {
1244		int hasv4addr;
1245		struct sockaddr_in6 *sin6 = NULL;
1246
1247		if (addr == NULL)
1248			hasv4addr = (inp->inp_vflag & INP_IPV4);
1249		else {
1250			sin6 = (struct sockaddr_in6 *)addr;
1251			hasv4addr = IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)
1252			    ? 1 : 0;
1253		}
1254		if (hasv4addr) {
1255			struct pr_usrreqs *pru;
1256			uint8_t nxt;
1257
1258			nxt = (inp->inp_socket->so_proto->pr_protocol ==
1259			    IPPROTO_UDP) ? IPPROTO_UDP : IPPROTO_UDPLITE;
1260			/*
1261			 * XXXRW: We release UDP-layer locks before calling
1262			 * udp_send() in order to avoid recursion.  However,
1263			 * this does mean there is a short window where inp's
1264			 * fields are unstable.  Could this lead to a
1265			 * potential race in which the factors causing us to
1266			 * select the UDPv4 output routine are invalidated?
1267			 */
1268			INP_WUNLOCK(inp);
1269			if (sin6)
1270				in6_sin6_2_sin_in_sock(addr);
1271			pru = inetsw[ip_protox[nxt]].pr_usrreqs;
1272			/* addr will just be freed in sendit(). */
1273			return ((*pru->pru_send)(so, flags, m, addr, control,
1274			    td));
1275		}
1276	}
1277#endif
1278#ifdef MAC
1279	mac_inpcb_create_mbuf(inp, m);
1280#endif
1281	INP_HASH_WLOCK(pcbinfo);
1282	error = udp6_output(inp, m, addr, control, td);
1283	INP_HASH_WUNLOCK(pcbinfo);
1284	INP_WUNLOCK(inp);
1285	return (error);
1286
1287bad:
1288	INP_WUNLOCK(inp);
1289	m_freem(m);
1290	return (error);
1291}
1292
1293struct pr_usrreqs udp6_usrreqs = {
1294	.pru_abort =		udp6_abort,
1295	.pru_attach =		udp6_attach,
1296	.pru_bind =		udp6_bind,
1297	.pru_connect =		udp6_connect,
1298	.pru_control =		in6_control,
1299	.pru_detach =		udp6_detach,
1300	.pru_disconnect =	udp6_disconnect,
1301	.pru_peeraddr =		in6_mapped_peeraddr,
1302	.pru_send =		udp6_send,
1303	.pru_shutdown =		udp_shutdown,
1304	.pru_sockaddr =		in6_mapped_sockaddr,
1305	.pru_soreceive =	soreceive_dgram,
1306	.pru_sosend =		sosend_dgram,
1307	.pru_sosetlabel =	in_pcbsosetlabel,
1308	.pru_close =		udp6_close
1309};
1310