xref: /freebsd/sys/netinet6/udp6_usrreq.c (revision 70e0bbedef95258a4dadc996d641a9bebd3f107d)
1 /*-
2  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
3  * Copyright (c) 2010-2011 Juniper Networks, Inc.
4  * All rights reserved.
5  *
6  * Portions of this software were developed by Robert N. M. Watson under
7  * contract to Juniper Networks, Inc.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. Neither the name of the project nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  *	$KAME: udp6_usrreq.c,v 1.27 2001/05/21 05:45:10 jinmei Exp $
34  *	$KAME: udp6_output.c,v 1.31 2001/05/21 16:39:15 jinmei Exp $
35  */
36 
37 /*-
38  * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
39  *	The Regents of the University of California.
40  * All rights reserved.
41  *
42  * Redistribution and use in source and binary forms, with or without
43  * modification, are permitted provided that the following conditions
44  * are met:
45  * 1. Redistributions of source code must retain the above copyright
46  *    notice, this list of conditions and the following disclaimer.
47  * 2. Redistributions in binary form must reproduce the above copyright
48  *    notice, this list of conditions and the following disclaimer in the
49  *    documentation and/or other materials provided with the distribution.
50  * 4. Neither the name of the University nor the names of its contributors
51  *    may be used to endorse or promote products derived from this software
52  *    without specific prior written permission.
53  *
54  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
55  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
56  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
57  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
58  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
59  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
60  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
61  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
62  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
63  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
64  * SUCH DAMAGE.
65  *
66  *	@(#)udp_usrreq.c	8.6 (Berkeley) 5/23/95
67  */
68 
69 #include <sys/cdefs.h>
70 __FBSDID("$FreeBSD$");
71 
72 #include "opt_inet.h"
73 #include "opt_inet6.h"
74 #include "opt_ipfw.h"
75 #include "opt_ipsec.h"
76 
77 #include <sys/param.h>
78 #include <sys/jail.h>
79 #include <sys/kernel.h>
80 #include <sys/lock.h>
81 #include <sys/mbuf.h>
82 #include <sys/priv.h>
83 #include <sys/proc.h>
84 #include <sys/protosw.h>
85 #include <sys/signalvar.h>
86 #include <sys/socket.h>
87 #include <sys/socketvar.h>
88 #include <sys/sx.h>
89 #include <sys/sysctl.h>
90 #include <sys/syslog.h>
91 #include <sys/systm.h>
92 
93 #include <net/if.h>
94 #include <net/if_types.h>
95 #include <net/route.h>
96 
97 #include <netinet/in.h>
98 #include <netinet/in_pcb.h>
99 #include <netinet/in_systm.h>
100 #include <netinet/in_var.h>
101 #include <netinet/ip.h>
102 #include <netinet/ip_icmp.h>
103 #include <netinet/ip6.h>
104 #include <netinet/icmp_var.h>
105 #include <netinet/icmp6.h>
106 #include <netinet/ip_var.h>
107 #include <netinet/udp.h>
108 #include <netinet/udp_var.h>
109 
110 #include <netinet6/ip6protosw.h>
111 #include <netinet6/ip6_var.h>
112 #include <netinet6/in6_pcb.h>
113 #include <netinet6/udp6_var.h>
114 #include <netinet6/scope6_var.h>
115 
116 #ifdef IPSEC
117 #include <netipsec/ipsec.h>
118 #include <netipsec/ipsec6.h>
119 #endif /* IPSEC */
120 
121 #include <security/mac/mac_framework.h>
122 
123 /*
124  * UDP protocol implementation.
125  * Per RFC 768, August, 1980.
126  */
127 
128 extern struct protosw	inetsw[];
129 static void		udp6_detach(struct socket *so);
130 
131 static void
132 udp6_append(struct inpcb *inp, struct mbuf *n, int off,
133     struct sockaddr_in6 *fromsa)
134 {
135 	struct socket *so;
136 	struct mbuf *opts;
137 
138 	INP_LOCK_ASSERT(inp);
139 
140 #ifdef IPSEC
141 	/* Check AH/ESP integrity. */
142 	if (ipsec6_in_reject(n, inp)) {
143 		m_freem(n);
144 		V_ipsec6stat.in_polvio++;
145 		return;
146 	}
147 #endif /* IPSEC */
148 #ifdef MAC
149 	if (mac_inpcb_check_deliver(inp, n) != 0) {
150 		m_freem(n);
151 		return;
152 	}
153 #endif
154 	opts = NULL;
155 	if (inp->inp_flags & INP_CONTROLOPTS ||
156 	    inp->inp_socket->so_options & SO_TIMESTAMP)
157 		ip6_savecontrol(inp, n, &opts);
158 	m_adj(n, off + sizeof(struct udphdr));
159 
160 	so = inp->inp_socket;
161 	SOCKBUF_LOCK(&so->so_rcv);
162 	if (sbappendaddr_locked(&so->so_rcv, (struct sockaddr *)fromsa, n,
163 	    opts) == 0) {
164 		SOCKBUF_UNLOCK(&so->so_rcv);
165 		m_freem(n);
166 		if (opts)
167 			m_freem(opts);
168 		UDPSTAT_INC(udps_fullsock);
169 	} else
170 		sorwakeup_locked(so);
171 }
172 
173 int
174 udp6_input(struct mbuf **mp, int *offp, int proto)
175 {
176 	struct mbuf *m = *mp;
177 	struct ifnet *ifp;
178 	struct ip6_hdr *ip6;
179 	struct udphdr *uh;
180 	struct inpcb *inp;
181 	struct udpcb *up;
182 	int off = *offp;
183 	int plen, ulen;
184 	struct sockaddr_in6 fromsa;
185 #ifdef IPFIREWALL_FORWARD
186 	struct m_tag *fwd_tag;
187 #endif
188 
189 	ifp = m->m_pkthdr.rcvif;
190 	ip6 = mtod(m, struct ip6_hdr *);
191 
192 	if (faithprefix_p != NULL && (*faithprefix_p)(&ip6->ip6_dst)) {
193 		/* XXX send icmp6 host/port unreach? */
194 		m_freem(m);
195 		return (IPPROTO_DONE);
196 	}
197 
198 #ifndef PULLDOWN_TEST
199 	IP6_EXTHDR_CHECK(m, off, sizeof(struct udphdr), IPPROTO_DONE);
200 	ip6 = mtod(m, struct ip6_hdr *);
201 	uh = (struct udphdr *)((caddr_t)ip6 + off);
202 #else
203 	IP6_EXTHDR_GET(uh, struct udphdr *, m, off, sizeof(*uh));
204 	if (!uh)
205 		return (IPPROTO_DONE);
206 #endif
207 
208 	UDPSTAT_INC(udps_ipackets);
209 
210 	/*
211 	 * Destination port of 0 is illegal, based on RFC768.
212 	 */
213 	if (uh->uh_dport == 0)
214 		goto badunlocked;
215 
216 	plen = ntohs(ip6->ip6_plen) - off + sizeof(*ip6);
217 	ulen = ntohs((u_short)uh->uh_ulen);
218 
219 	if (plen != ulen) {
220 		UDPSTAT_INC(udps_badlen);
221 		goto badunlocked;
222 	}
223 
224 	/*
225 	 * Checksum extended UDP header and data.
226 	 */
227 	if (uh->uh_sum == 0) {
228 		UDPSTAT_INC(udps_nosum);
229 		goto badunlocked;
230 	}
231 	if (in6_cksum(m, IPPROTO_UDP, off, ulen) != 0) {
232 		UDPSTAT_INC(udps_badsum);
233 		goto badunlocked;
234 	}
235 
236 	/*
237 	 * Construct sockaddr format source address.
238 	 */
239 	init_sin6(&fromsa, m);
240 	fromsa.sin6_port = uh->uh_sport;
241 
242 	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
243 		struct inpcb *last;
244 		struct ip6_moptions *imo;
245 
246 		INP_INFO_RLOCK(&V_udbinfo);
247 		/*
248 		 * In the event that laddr should be set to the link-local
249 		 * address (this happens in RIPng), the multicast address
250 		 * specified in the received packet will not match laddr.  To
251 		 * handle this situation, matching is relaxed if the
252 		 * receiving interface is the same as one specified in the
253 		 * socket and if the destination multicast address matches
254 		 * one of the multicast groups specified in the socket.
255 		 */
256 
257 		/*
258 		 * KAME note: traditionally we dropped udpiphdr from mbuf
259 		 * here.  We need udphdr for IPsec processing so we do that
260 		 * later.
261 		 */
262 		last = NULL;
263 		LIST_FOREACH(inp, &V_udb, inp_list) {
264 			if ((inp->inp_vflag & INP_IPV6) == 0)
265 				continue;
266 			if (inp->inp_lport != uh->uh_dport)
267 				continue;
268 			if (inp->inp_fport != 0 &&
269 			    inp->inp_fport != uh->uh_sport)
270 				continue;
271 			if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr)) {
272 				if (!IN6_ARE_ADDR_EQUAL(&inp->in6p_laddr,
273 							&ip6->ip6_dst))
274 					continue;
275 			}
276 			if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
277 				if (!IN6_ARE_ADDR_EQUAL(&inp->in6p_faddr,
278 							&ip6->ip6_src) ||
279 				    inp->inp_fport != uh->uh_sport)
280 					continue;
281 			}
282 
283 			/*
284 			 * XXXRW: Because we weren't holding either the inpcb
285 			 * or the hash lock when we checked for a match
286 			 * before, we should probably recheck now that the
287 			 * inpcb lock is (supposed to be) held.
288 			 */
289 
290 			/*
291 			 * Handle socket delivery policy for any-source
292 			 * and source-specific multicast. [RFC3678]
293 			 */
294 			imo = inp->in6p_moptions;
295 			if (imo && IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
296 				struct sockaddr_in6	 mcaddr;
297 				int			 blocked;
298 
299 				INP_RLOCK(inp);
300 
301 				bzero(&mcaddr, sizeof(struct sockaddr_in6));
302 				mcaddr.sin6_len = sizeof(struct sockaddr_in6);
303 				mcaddr.sin6_family = AF_INET6;
304 				mcaddr.sin6_addr = ip6->ip6_dst;
305 
306 				blocked = im6o_mc_filter(imo, ifp,
307 					(struct sockaddr *)&mcaddr,
308 					(struct sockaddr *)&fromsa);
309 				if (blocked != MCAST_PASS) {
310 					if (blocked == MCAST_NOTGMEMBER)
311 						IP6STAT_INC(ip6s_notmember);
312 					if (blocked == MCAST_NOTSMEMBER ||
313 					    blocked == MCAST_MUTED)
314 						UDPSTAT_INC(udps_filtermcast);
315 					INP_RUNLOCK(inp); /* XXX */
316 					continue;
317 				}
318 
319 				INP_RUNLOCK(inp);
320 			}
321 			if (last != NULL) {
322 				struct mbuf *n;
323 
324 				if ((n = m_copy(m, 0, M_COPYALL)) != NULL) {
325 					INP_RLOCK(last);
326 					up = intoudpcb(last);
327 					if (up->u_tun_func == NULL) {
328 						udp6_append(last, n, off, &fromsa);
329 					} else {
330 						/*
331 						 * Engage the tunneling
332 						 * protocol we will have to
333 						 * leave the info_lock up,
334 						 * since we are hunting
335 						 * through multiple UDP's.
336 						 *
337 						 */
338 						(*up->u_tun_func)(n, off, last);
339 					}
340 					INP_RUNLOCK(last);
341 				}
342 			}
343 			last = inp;
344 			/*
345 			 * Don't look for additional matches if this one does
346 			 * not have either the SO_REUSEPORT or SO_REUSEADDR
347 			 * socket options set.  This heuristic avoids
348 			 * searching through all pcbs in the common case of a
349 			 * non-shared port.  It assumes that an application
350 			 * will never clear these options after setting them.
351 			 */
352 			if ((last->inp_socket->so_options &
353 			     (SO_REUSEPORT|SO_REUSEADDR)) == 0)
354 				break;
355 		}
356 
357 		if (last == NULL) {
358 			/*
359 			 * No matching pcb found; discard datagram.  (No need
360 			 * to send an ICMP Port Unreachable for a broadcast
361 			 * or multicast datgram.)
362 			 */
363 			UDPSTAT_INC(udps_noport);
364 			UDPSTAT_INC(udps_noportmcast);
365 			goto badheadlocked;
366 		}
367 		INP_RLOCK(last);
368 		INP_INFO_RUNLOCK(&V_udbinfo);
369 		up = intoudpcb(last);
370 		if (up->u_tun_func == NULL) {
371 			udp6_append(last, m, off, &fromsa);
372 		} else {
373 			/*
374 			 * Engage the tunneling protocol.
375 			 */
376 			(*up->u_tun_func)(m, off, last);
377 		}
378 		INP_RUNLOCK(last);
379 		return (IPPROTO_DONE);
380 	}
381 	/*
382 	 * Locate pcb for datagram.
383 	 */
384 #ifdef IPFIREWALL_FORWARD
385 	/*
386 	 * Grab info from PACKET_TAG_IPFORWARD tag prepended to the chain.
387 	 */
388 	fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
389 	if (fwd_tag != NULL) {
390 		struct sockaddr_in6 *next_hop6;
391 
392 		next_hop6 = (struct sockaddr_in6 *)(fwd_tag + 1);
393 
394 		/*
395 		 * Transparently forwarded. Pretend to be the destination.
396 		 * Already got one like this?
397 		 */
398 		inp = in6_pcblookup_mbuf(&V_udbinfo,
399 		    &ip6->ip6_src, uh->uh_sport, &ip6->ip6_dst, uh->uh_dport,
400 		    INPLOOKUP_RLOCKPCB, m->m_pkthdr.rcvif, m);
401 		if (!inp) {
402 			/*
403 			 * It's new.  Try to find the ambushing socket.
404 			 * Because we've rewritten the destination address,
405 			 * any hardware-generated hash is ignored.
406 			 */
407 			inp = in6_pcblookup(&V_udbinfo, &ip6->ip6_src,
408 			    uh->uh_sport, &next_hop6->sin6_addr,
409 			    next_hop6->sin6_port ? htons(next_hop6->sin6_port) :
410 			    uh->uh_dport, INPLOOKUP_WILDCARD |
411 			    INPLOOKUP_RLOCKPCB, m->m_pkthdr.rcvif);
412 		}
413 		/* Remove the tag from the packet. We don't need it anymore. */
414 		m_tag_delete(m, fwd_tag);
415 	} else
416 #endif /* IPFIREWALL_FORWARD */
417 		inp = in6_pcblookup_mbuf(&V_udbinfo, &ip6->ip6_src,
418 		    uh->uh_sport, &ip6->ip6_dst, uh->uh_dport,
419 		    INPLOOKUP_WILDCARD | INPLOOKUP_RLOCKPCB,
420 		    m->m_pkthdr.rcvif, m);
421 	if (inp == NULL) {
422 		if (udp_log_in_vain) {
423 			char ip6bufs[INET6_ADDRSTRLEN];
424 			char ip6bufd[INET6_ADDRSTRLEN];
425 
426 			log(LOG_INFO,
427 			    "Connection attempt to UDP [%s]:%d from [%s]:%d\n",
428 			    ip6_sprintf(ip6bufd, &ip6->ip6_dst),
429 			    ntohs(uh->uh_dport),
430 			    ip6_sprintf(ip6bufs, &ip6->ip6_src),
431 			    ntohs(uh->uh_sport));
432 		}
433 		UDPSTAT_INC(udps_noport);
434 		if (m->m_flags & M_MCAST) {
435 			printf("UDP6: M_MCAST is set in a unicast packet.\n");
436 			UDPSTAT_INC(udps_noportmcast);
437 			goto badunlocked;
438 		}
439 		if (V_udp_blackhole)
440 			goto badunlocked;
441 		if (badport_bandlim(BANDLIM_ICMP6_UNREACH) < 0)
442 			goto badunlocked;
443 		icmp6_error(m, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOPORT, 0);
444 		return (IPPROTO_DONE);
445 	}
446 	INP_RLOCK_ASSERT(inp);
447 	up = intoudpcb(inp);
448 	if (up->u_tun_func == NULL) {
449 		udp6_append(inp, m, off, &fromsa);
450 	} else {
451 		/*
452 		 * Engage the tunneling protocol.
453 		 */
454 
455 		(*up->u_tun_func)(m, off, inp);
456 	}
457 	INP_RUNLOCK(inp);
458 	return (IPPROTO_DONE);
459 
460 badheadlocked:
461 	INP_INFO_RUNLOCK(&V_udbinfo);
462 badunlocked:
463 	if (m)
464 		m_freem(m);
465 	return (IPPROTO_DONE);
466 }
467 
468 void
469 udp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
470 {
471 	struct udphdr uh;
472 	struct ip6_hdr *ip6;
473 	struct mbuf *m;
474 	int off = 0;
475 	struct ip6ctlparam *ip6cp = NULL;
476 	const struct sockaddr_in6 *sa6_src = NULL;
477 	void *cmdarg;
478 	struct inpcb *(*notify)(struct inpcb *, int) = udp_notify;
479 	struct udp_portonly {
480 		u_int16_t uh_sport;
481 		u_int16_t uh_dport;
482 	} *uhp;
483 
484 	if (sa->sa_family != AF_INET6 ||
485 	    sa->sa_len != sizeof(struct sockaddr_in6))
486 		return;
487 
488 	if ((unsigned)cmd >= PRC_NCMDS)
489 		return;
490 	if (PRC_IS_REDIRECT(cmd))
491 		notify = in6_rtchange, d = NULL;
492 	else if (cmd == PRC_HOSTDEAD)
493 		d = NULL;
494 	else if (inet6ctlerrmap[cmd] == 0)
495 		return;
496 
497 	/* if the parameter is from icmp6, decode it. */
498 	if (d != NULL) {
499 		ip6cp = (struct ip6ctlparam *)d;
500 		m = ip6cp->ip6c_m;
501 		ip6 = ip6cp->ip6c_ip6;
502 		off = ip6cp->ip6c_off;
503 		cmdarg = ip6cp->ip6c_cmdarg;
504 		sa6_src = ip6cp->ip6c_src;
505 	} else {
506 		m = NULL;
507 		ip6 = NULL;
508 		cmdarg = NULL;
509 		sa6_src = &sa6_any;
510 	}
511 
512 	if (ip6) {
513 		/*
514 		 * XXX: We assume that when IPV6 is non NULL,
515 		 * M and OFF are valid.
516 		 */
517 
518 		/* Check if we can safely examine src and dst ports. */
519 		if (m->m_pkthdr.len < off + sizeof(*uhp))
520 			return;
521 
522 		bzero(&uh, sizeof(uh));
523 		m_copydata(m, off, sizeof(*uhp), (caddr_t)&uh);
524 
525 		(void) in6_pcbnotify(&V_udbinfo, sa, uh.uh_dport,
526 		    (struct sockaddr *)ip6cp->ip6c_src, uh.uh_sport, cmd,
527 		    cmdarg, notify);
528 	} else
529 		(void) in6_pcbnotify(&V_udbinfo, sa, 0,
530 		    (const struct sockaddr *)sa6_src, 0, cmd, cmdarg, notify);
531 }
532 
533 static int
534 udp6_getcred(SYSCTL_HANDLER_ARGS)
535 {
536 	struct xucred xuc;
537 	struct sockaddr_in6 addrs[2];
538 	struct inpcb *inp;
539 	int error;
540 
541 	error = priv_check(req->td, PRIV_NETINET_GETCRED);
542 	if (error)
543 		return (error);
544 
545 	if (req->newlen != sizeof(addrs))
546 		return (EINVAL);
547 	if (req->oldlen != sizeof(struct xucred))
548 		return (EINVAL);
549 	error = SYSCTL_IN(req, addrs, sizeof(addrs));
550 	if (error)
551 		return (error);
552 	if ((error = sa6_embedscope(&addrs[0], V_ip6_use_defzone)) != 0 ||
553 	    (error = sa6_embedscope(&addrs[1], V_ip6_use_defzone)) != 0) {
554 		return (error);
555 	}
556 	inp = in6_pcblookup(&V_udbinfo, &addrs[1].sin6_addr,
557 	    addrs[1].sin6_port, &addrs[0].sin6_addr, addrs[0].sin6_port,
558 	    INPLOOKUP_WILDCARD | INPLOOKUP_RLOCKPCB, NULL);
559 	if (inp != NULL) {
560 		INP_RLOCK_ASSERT(inp);
561 		if (inp->inp_socket == NULL)
562 			error = ENOENT;
563 		if (error == 0)
564 			error = cr_canseesocket(req->td->td_ucred,
565 			    inp->inp_socket);
566 		if (error == 0)
567 			cru2x(inp->inp_cred, &xuc);
568 		INP_RUNLOCK(inp);
569 	} else
570 		error = ENOENT;
571 	if (error == 0)
572 		error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
573 	return (error);
574 }
575 
576 SYSCTL_PROC(_net_inet6_udp6, OID_AUTO, getcred, CTLTYPE_OPAQUE|CTLFLAG_RW, 0,
577     0, udp6_getcred, "S,xucred", "Get the xucred of a UDP6 connection");
578 
579 static int
580 udp6_output(struct inpcb *inp, struct mbuf *m, struct sockaddr *addr6,
581     struct mbuf *control, struct thread *td)
582 {
583 	u_int32_t ulen = m->m_pkthdr.len;
584 	u_int32_t plen = sizeof(struct udphdr) + ulen;
585 	struct ip6_hdr *ip6;
586 	struct udphdr *udp6;
587 	struct in6_addr *laddr, *faddr, in6a;
588 	struct sockaddr_in6 *sin6 = NULL;
589 	struct ifnet *oifp = NULL;
590 	int scope_ambiguous = 0;
591 	u_short fport;
592 	int error = 0;
593 	struct ip6_pktopts *optp, opt;
594 	int af = AF_INET6, hlen = sizeof(struct ip6_hdr);
595 	int flags;
596 	struct sockaddr_in6 tmp;
597 
598 	INP_WLOCK_ASSERT(inp);
599 	INP_HASH_WLOCK_ASSERT(inp->inp_pcbinfo);
600 
601 	if (addr6) {
602 		/* addr6 has been validated in udp6_send(). */
603 		sin6 = (struct sockaddr_in6 *)addr6;
604 
605 		/* protect *sin6 from overwrites */
606 		tmp = *sin6;
607 		sin6 = &tmp;
608 
609 		/*
610 		 * Application should provide a proper zone ID or the use of
611 		 * default zone IDs should be enabled.  Unfortunately, some
612 		 * applications do not behave as it should, so we need a
613 		 * workaround.  Even if an appropriate ID is not determined,
614 		 * we'll see if we can determine the outgoing interface.  If we
615 		 * can, determine the zone ID based on the interface below.
616 		 */
617 		if (sin6->sin6_scope_id == 0 && !V_ip6_use_defzone)
618 			scope_ambiguous = 1;
619 		if ((error = sa6_embedscope(sin6, V_ip6_use_defzone)) != 0)
620 			return (error);
621 	}
622 
623 	if (control) {
624 		if ((error = ip6_setpktopts(control, &opt,
625 		    inp->in6p_outputopts, td->td_ucred, IPPROTO_UDP)) != 0)
626 			goto release;
627 		optp = &opt;
628 	} else
629 		optp = inp->in6p_outputopts;
630 
631 	if (sin6) {
632 		faddr = &sin6->sin6_addr;
633 
634 		/*
635 		 * IPv4 version of udp_output calls in_pcbconnect in this case,
636 		 * which needs splnet and affects performance.
637 		 * Since we saw no essential reason for calling in_pcbconnect,
638 		 * we get rid of such kind of logic, and call in6_selectsrc
639 		 * and in6_pcbsetport in order to fill in the local address
640 		 * and the local port.
641 		 */
642 		if (sin6->sin6_port == 0) {
643 			error = EADDRNOTAVAIL;
644 			goto release;
645 		}
646 
647 		if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
648 			/* how about ::ffff:0.0.0.0 case? */
649 			error = EISCONN;
650 			goto release;
651 		}
652 
653 		fport = sin6->sin6_port; /* allow 0 port */
654 
655 		if (IN6_IS_ADDR_V4MAPPED(faddr)) {
656 			if ((inp->inp_flags & IN6P_IPV6_V6ONLY)) {
657 				/*
658 				 * I believe we should explicitly discard the
659 				 * packet when mapped addresses are disabled,
660 				 * rather than send the packet as an IPv6 one.
661 				 * If we chose the latter approach, the packet
662 				 * might be sent out on the wire based on the
663 				 * default route, the situation which we'd
664 				 * probably want to avoid.
665 				 * (20010421 jinmei@kame.net)
666 				 */
667 				error = EINVAL;
668 				goto release;
669 			}
670 			if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr) &&
671 			    !IN6_IS_ADDR_V4MAPPED(&inp->in6p_laddr)) {
672 				/*
673 				 * when remote addr is an IPv4-mapped address,
674 				 * local addr should not be an IPv6 address,
675 				 * since you cannot determine how to map IPv6
676 				 * source address to IPv4.
677 				 */
678 				error = EINVAL;
679 				goto release;
680 			}
681 
682 			af = AF_INET;
683 		}
684 
685 		if (!IN6_IS_ADDR_V4MAPPED(faddr)) {
686 			error = in6_selectsrc(sin6, optp, inp, NULL,
687 			    td->td_ucred, &oifp, &in6a);
688 			if (error)
689 				goto release;
690 			if (oifp && scope_ambiguous &&
691 			    (error = in6_setscope(&sin6->sin6_addr,
692 			    oifp, NULL))) {
693 				goto release;
694 			}
695 			laddr = &in6a;
696 		} else
697 			laddr = &inp->in6p_laddr;	/* XXX */
698 		if (laddr == NULL) {
699 			if (error == 0)
700 				error = EADDRNOTAVAIL;
701 			goto release;
702 		}
703 		if (inp->inp_lport == 0 &&
704 		    (error = in6_pcbsetport(laddr, inp, td->td_ucred)) != 0) {
705 			/* Undo an address bind that may have occurred. */
706 			inp->in6p_laddr = in6addr_any;
707 			goto release;
708 		}
709 	} else {
710 		if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
711 			error = ENOTCONN;
712 			goto release;
713 		}
714 		if (IN6_IS_ADDR_V4MAPPED(&inp->in6p_faddr)) {
715 			if ((inp->inp_flags & IN6P_IPV6_V6ONLY)) {
716 				/*
717 				 * XXX: this case would happen when the
718 				 * application sets the V6ONLY flag after
719 				 * connecting the foreign address.
720 				 * Such applications should be fixed,
721 				 * so we bark here.
722 				 */
723 				log(LOG_INFO, "udp6_output: IPV6_V6ONLY "
724 				    "option was set for a connected socket\n");
725 				error = EINVAL;
726 				goto release;
727 			} else
728 				af = AF_INET;
729 		}
730 		laddr = &inp->in6p_laddr;
731 		faddr = &inp->in6p_faddr;
732 		fport = inp->inp_fport;
733 	}
734 
735 	if (af == AF_INET)
736 		hlen = sizeof(struct ip);
737 
738 	/*
739 	 * Calculate data length and get a mbuf
740 	 * for UDP and IP6 headers.
741 	 */
742 	M_PREPEND(m, hlen + sizeof(struct udphdr), M_DONTWAIT);
743 	if (m == 0) {
744 		error = ENOBUFS;
745 		goto release;
746 	}
747 
748 	/*
749 	 * Stuff checksum and output datagram.
750 	 */
751 	udp6 = (struct udphdr *)(mtod(m, caddr_t) + hlen);
752 	udp6->uh_sport = inp->inp_lport; /* lport is always set in the PCB */
753 	udp6->uh_dport = fport;
754 	if (plen <= 0xffff)
755 		udp6->uh_ulen = htons((u_short)plen);
756 	else
757 		udp6->uh_ulen = 0;
758 	udp6->uh_sum = 0;
759 
760 	switch (af) {
761 	case AF_INET6:
762 		ip6 = mtod(m, struct ip6_hdr *);
763 		ip6->ip6_flow	= inp->inp_flow & IPV6_FLOWINFO_MASK;
764 		ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
765 		ip6->ip6_vfc	|= IPV6_VERSION;
766 #if 0				/* ip6_plen will be filled in ip6_output. */
767 		ip6->ip6_plen	= htons((u_short)plen);
768 #endif
769 		ip6->ip6_nxt	= IPPROTO_UDP;
770 		ip6->ip6_hlim	= in6_selecthlim(inp, NULL);
771 		ip6->ip6_src	= *laddr;
772 		ip6->ip6_dst	= *faddr;
773 
774 		if ((udp6->uh_sum = in6_cksum(m, IPPROTO_UDP,
775 				sizeof(struct ip6_hdr), plen)) == 0) {
776 			udp6->uh_sum = 0xffff;
777 		}
778 
779 		flags = 0;
780 
781 		UDPSTAT_INC(udps_opackets);
782 		error = ip6_output(m, optp, NULL, flags, inp->in6p_moptions,
783 		    NULL, inp);
784 		break;
785 	case AF_INET:
786 		error = EAFNOSUPPORT;
787 		goto release;
788 	}
789 	goto releaseopt;
790 
791 release:
792 	m_freem(m);
793 
794 releaseopt:
795 	if (control) {
796 		ip6_clearpktopts(&opt, -1);
797 		m_freem(control);
798 	}
799 	return (error);
800 }
801 
802 static void
803 udp6_abort(struct socket *so)
804 {
805 	struct inpcb *inp;
806 
807 	inp = sotoinpcb(so);
808 	KASSERT(inp != NULL, ("udp6_abort: inp == NULL"));
809 
810 #ifdef INET
811 	if (inp->inp_vflag & INP_IPV4) {
812 		struct pr_usrreqs *pru;
813 
814 		pru = inetsw[ip_protox[IPPROTO_UDP]].pr_usrreqs;
815 		(*pru->pru_abort)(so);
816 		return;
817 	}
818 #endif
819 
820 	INP_WLOCK(inp);
821 	if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
822 		INP_HASH_WLOCK(&V_udbinfo);
823 		in6_pcbdisconnect(inp);
824 		inp->in6p_laddr = in6addr_any;
825 		INP_HASH_WUNLOCK(&V_udbinfo);
826 		soisdisconnected(so);
827 	}
828 	INP_WUNLOCK(inp);
829 }
830 
831 static int
832 udp6_attach(struct socket *so, int proto, struct thread *td)
833 {
834 	struct inpcb *inp;
835 	int error;
836 
837 	inp = sotoinpcb(so);
838 	KASSERT(inp == NULL, ("udp6_attach: inp != NULL"));
839 
840 	if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
841 		error = soreserve(so, udp_sendspace, udp_recvspace);
842 		if (error)
843 			return (error);
844 	}
845 	INP_INFO_WLOCK(&V_udbinfo);
846 	error = in_pcballoc(so, &V_udbinfo);
847 	if (error) {
848 		INP_INFO_WUNLOCK(&V_udbinfo);
849 		return (error);
850 	}
851 	inp = (struct inpcb *)so->so_pcb;
852 	inp->inp_vflag |= INP_IPV6;
853 	if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0)
854 		inp->inp_vflag |= INP_IPV4;
855 	inp->in6p_hops = -1;	/* use kernel default */
856 	inp->in6p_cksum = -1;	/* just to be sure */
857 	/*
858 	 * XXX: ugly!!
859 	 * IPv4 TTL initialization is necessary for an IPv6 socket as well,
860 	 * because the socket may be bound to an IPv6 wildcard address,
861 	 * which may match an IPv4-mapped IPv6 address.
862 	 */
863 	inp->inp_ip_ttl = V_ip_defttl;
864 
865 	error = udp_newudpcb(inp);
866 	if (error) {
867 		in_pcbdetach(inp);
868 		in_pcbfree(inp);
869 		INP_INFO_WUNLOCK(&V_udbinfo);
870 		return (error);
871 	}
872 	INP_WUNLOCK(inp);
873 	INP_INFO_WUNLOCK(&V_udbinfo);
874 	return (0);
875 }
876 
877 static int
878 udp6_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
879 {
880 	struct inpcb *inp;
881 	int error;
882 
883 	inp = sotoinpcb(so);
884 	KASSERT(inp != NULL, ("udp6_bind: inp == NULL"));
885 
886 	INP_WLOCK(inp);
887 	INP_HASH_WLOCK(&V_udbinfo);
888 	inp->inp_vflag &= ~INP_IPV4;
889 	inp->inp_vflag |= INP_IPV6;
890 	if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0) {
891 		struct sockaddr_in6 *sin6_p;
892 
893 		sin6_p = (struct sockaddr_in6 *)nam;
894 
895 		if (IN6_IS_ADDR_UNSPECIFIED(&sin6_p->sin6_addr))
896 			inp->inp_vflag |= INP_IPV4;
897 #ifdef INET
898 		else if (IN6_IS_ADDR_V4MAPPED(&sin6_p->sin6_addr)) {
899 			struct sockaddr_in sin;
900 
901 			in6_sin6_2_sin(&sin, sin6_p);
902 			inp->inp_vflag |= INP_IPV4;
903 			inp->inp_vflag &= ~INP_IPV6;
904 			error = in_pcbbind(inp, (struct sockaddr *)&sin,
905 			    td->td_ucred);
906 			goto out;
907 		}
908 #endif
909 	}
910 
911 	error = in6_pcbbind(inp, nam, td->td_ucred);
912 #ifdef INET
913 out:
914 #endif
915 	INP_HASH_WUNLOCK(&V_udbinfo);
916 	INP_WUNLOCK(inp);
917 	return (error);
918 }
919 
920 static void
921 udp6_close(struct socket *so)
922 {
923 	struct inpcb *inp;
924 
925 	inp = sotoinpcb(so);
926 	KASSERT(inp != NULL, ("udp6_close: inp == NULL"));
927 
928 #ifdef INET
929 	if (inp->inp_vflag & INP_IPV4) {
930 		struct pr_usrreqs *pru;
931 
932 		pru = inetsw[ip_protox[IPPROTO_UDP]].pr_usrreqs;
933 		(*pru->pru_disconnect)(so);
934 		return;
935 	}
936 #endif
937 	INP_WLOCK(inp);
938 	if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
939 		INP_HASH_WLOCK(&V_udbinfo);
940 		in6_pcbdisconnect(inp);
941 		inp->in6p_laddr = in6addr_any;
942 		INP_HASH_WUNLOCK(&V_udbinfo);
943 		soisdisconnected(so);
944 	}
945 	INP_WUNLOCK(inp);
946 }
947 
948 static int
949 udp6_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
950 {
951 	struct inpcb *inp;
952 	struct sockaddr_in6 *sin6;
953 	int error;
954 
955 	inp = sotoinpcb(so);
956 	sin6 = (struct sockaddr_in6 *)nam;
957 	KASSERT(inp != NULL, ("udp6_connect: inp == NULL"));
958 
959 	/*
960 	 * XXXRW: Need to clarify locking of v4/v6 flags.
961 	 */
962 	INP_WLOCK(inp);
963 #ifdef INET
964 	if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) {
965 		struct sockaddr_in sin;
966 
967 		if ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0) {
968 			error = EINVAL;
969 			goto out;
970 		}
971 		if (inp->inp_faddr.s_addr != INADDR_ANY) {
972 			error = EISCONN;
973 			goto out;
974 		}
975 		in6_sin6_2_sin(&sin, sin6);
976 		inp->inp_vflag |= INP_IPV4;
977 		inp->inp_vflag &= ~INP_IPV6;
978 		error = prison_remote_ip4(td->td_ucred, &sin.sin_addr);
979 		if (error != 0)
980 			goto out;
981 		INP_HASH_WLOCK(&V_udbinfo);
982 		error = in_pcbconnect(inp, (struct sockaddr *)&sin,
983 		    td->td_ucred);
984 		INP_HASH_WUNLOCK(&V_udbinfo);
985 		if (error == 0)
986 			soisconnected(so);
987 		goto out;
988 	}
989 #endif
990 	if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
991 		error = EISCONN;
992 		goto out;
993 	}
994 	inp->inp_vflag &= ~INP_IPV4;
995 	inp->inp_vflag |= INP_IPV6;
996 	error = prison_remote_ip6(td->td_ucred, &sin6->sin6_addr);
997 	if (error != 0)
998 		goto out;
999 	INP_HASH_WLOCK(&V_udbinfo);
1000 	error = in6_pcbconnect(inp, nam, td->td_ucred);
1001 	INP_HASH_WUNLOCK(&V_udbinfo);
1002 	if (error == 0)
1003 		soisconnected(so);
1004 out:
1005 	INP_WUNLOCK(inp);
1006 	return (error);
1007 }
1008 
1009 static void
1010 udp6_detach(struct socket *so)
1011 {
1012 	struct inpcb *inp;
1013 	struct udpcb *up;
1014 
1015 	inp = sotoinpcb(so);
1016 	KASSERT(inp != NULL, ("udp6_detach: inp == NULL"));
1017 
1018 	INP_INFO_WLOCK(&V_udbinfo);
1019 	INP_WLOCK(inp);
1020 	up = intoudpcb(inp);
1021 	KASSERT(up != NULL, ("%s: up == NULL", __func__));
1022 	in_pcbdetach(inp);
1023 	in_pcbfree(inp);
1024 	INP_INFO_WUNLOCK(&V_udbinfo);
1025 	udp_discardcb(up);
1026 }
1027 
1028 static int
1029 udp6_disconnect(struct socket *so)
1030 {
1031 	struct inpcb *inp;
1032 	int error;
1033 
1034 	inp = sotoinpcb(so);
1035 	KASSERT(inp != NULL, ("udp6_disconnect: inp == NULL"));
1036 
1037 #ifdef INET
1038 	if (inp->inp_vflag & INP_IPV4) {
1039 		struct pr_usrreqs *pru;
1040 
1041 		pru = inetsw[ip_protox[IPPROTO_UDP]].pr_usrreqs;
1042 		(void)(*pru->pru_disconnect)(so);
1043 		return (0);
1044 	}
1045 #endif
1046 
1047 	INP_WLOCK(inp);
1048 
1049 	if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
1050 		error = ENOTCONN;
1051 		goto out;
1052 	}
1053 
1054 	INP_HASH_WLOCK(&V_udbinfo);
1055 	in6_pcbdisconnect(inp);
1056 	inp->in6p_laddr = in6addr_any;
1057 	INP_HASH_WUNLOCK(&V_udbinfo);
1058 	SOCK_LOCK(so);
1059 	so->so_state &= ~SS_ISCONNECTED;		/* XXX */
1060 	SOCK_UNLOCK(so);
1061 out:
1062 	INP_WUNLOCK(inp);
1063 	return (0);
1064 }
1065 
1066 static int
1067 udp6_send(struct socket *so, int flags, struct mbuf *m,
1068     struct sockaddr *addr, struct mbuf *control, struct thread *td)
1069 {
1070 	struct inpcb *inp;
1071 	int error = 0;
1072 
1073 	inp = sotoinpcb(so);
1074 	KASSERT(inp != NULL, ("udp6_send: inp == NULL"));
1075 
1076 	INP_WLOCK(inp);
1077 	if (addr) {
1078 		if (addr->sa_len != sizeof(struct sockaddr_in6)) {
1079 			error = EINVAL;
1080 			goto bad;
1081 		}
1082 		if (addr->sa_family != AF_INET6) {
1083 			error = EAFNOSUPPORT;
1084 			goto bad;
1085 		}
1086 	}
1087 
1088 #ifdef INET
1089 	if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0) {
1090 		int hasv4addr;
1091 		struct sockaddr_in6 *sin6 = 0;
1092 
1093 		if (addr == 0)
1094 			hasv4addr = (inp->inp_vflag & INP_IPV4);
1095 		else {
1096 			sin6 = (struct sockaddr_in6 *)addr;
1097 			hasv4addr = IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)
1098 			    ? 1 : 0;
1099 		}
1100 		if (hasv4addr) {
1101 			struct pr_usrreqs *pru;
1102 
1103 			/*
1104 			 * XXXRW: We release UDP-layer locks before calling
1105 			 * udp_send() in order to avoid recursion.  However,
1106 			 * this does mean there is a short window where inp's
1107 			 * fields are unstable.  Could this lead to a
1108 			 * potential race in which the factors causing us to
1109 			 * select the UDPv4 output routine are invalidated?
1110 			 */
1111 			INP_WUNLOCK(inp);
1112 			if (sin6)
1113 				in6_sin6_2_sin_in_sock(addr);
1114 			pru = inetsw[ip_protox[IPPROTO_UDP]].pr_usrreqs;
1115 			/* addr will just be freed in sendit(). */
1116 			return ((*pru->pru_send)(so, flags, m, addr, control,
1117 			    td));
1118 		}
1119 	}
1120 #endif
1121 #ifdef MAC
1122 	mac_inpcb_create_mbuf(inp, m);
1123 #endif
1124 	INP_HASH_WLOCK(&V_udbinfo);
1125 	error = udp6_output(inp, m, addr, control, td);
1126 	INP_HASH_WUNLOCK(&V_udbinfo);
1127 #ifdef INET
1128 #endif
1129 	INP_WUNLOCK(inp);
1130 	return (error);
1131 
1132 bad:
1133 	INP_WUNLOCK(inp);
1134 	m_freem(m);
1135 	return (error);
1136 }
1137 
1138 struct pr_usrreqs udp6_usrreqs = {
1139 	.pru_abort =		udp6_abort,
1140 	.pru_attach =		udp6_attach,
1141 	.pru_bind =		udp6_bind,
1142 	.pru_connect =		udp6_connect,
1143 	.pru_control =		in6_control,
1144 	.pru_detach =		udp6_detach,
1145 	.pru_disconnect =	udp6_disconnect,
1146 	.pru_peeraddr =		in6_mapped_peeraddr,
1147 	.pru_send =		udp6_send,
1148 	.pru_shutdown =		udp_shutdown,
1149 	.pru_sockaddr =		in6_mapped_sockaddr,
1150 	.pru_soreceive =	soreceive_dgram,
1151 	.pru_sosend =		sosend_dgram,
1152 	.pru_sosetlabel =	in_pcbsosetlabel,
1153 	.pru_close =		udp6_close
1154 };
1155