xref: /freebsd/sys/netinet6/ip6_output.c (revision 0572ccaa4543b0abef8ef81e384c1d04de9f3da1)
1 /*-
2  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the project nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  *	$KAME: ip6_output.c,v 1.279 2002/01/26 06:12:30 jinmei Exp $
30  */
31 
32 /*-
33  * Copyright (c) 1982, 1986, 1988, 1990, 1993
34  *	The Regents of the University of California.  All rights reserved.
35  *
36  * Redistribution and use in source and binary forms, with or without
37  * modification, are permitted provided that the following conditions
38  * are met:
39  * 1. Redistributions of source code must retain the above copyright
40  *    notice, this list of conditions and the following disclaimer.
41  * 2. Redistributions in binary form must reproduce the above copyright
42  *    notice, this list of conditions and the following disclaimer in the
43  *    documentation and/or other materials provided with the distribution.
44  * 4. Neither the name of the University nor the names of its contributors
45  *    may be used to endorse or promote products derived from this software
46  *    without specific prior written permission.
47  *
48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58  * SUCH DAMAGE.
59  *
60  *	@(#)ip_output.c	8.3 (Berkeley) 1/21/94
61  */
62 
63 #include <sys/cdefs.h>
64 __FBSDID("$FreeBSD$");
65 
66 #include "opt_inet.h"
67 #include "opt_inet6.h"
68 #include "opt_ipfw.h"
69 #include "opt_ipsec.h"
70 #include "opt_sctp.h"
71 #include "opt_route.h"
72 
73 #include <sys/param.h>
74 #include <sys/kernel.h>
75 #include <sys/malloc.h>
76 #include <sys/mbuf.h>
77 #include <sys/errno.h>
78 #include <sys/priv.h>
79 #include <sys/proc.h>
80 #include <sys/protosw.h>
81 #include <sys/socket.h>
82 #include <sys/socketvar.h>
83 #include <sys/syslog.h>
84 #include <sys/ucred.h>
85 
86 #include <machine/in_cksum.h>
87 
88 #include <net/if.h>
89 #include <net/if_var.h>
90 #include <net/netisr.h>
91 #include <net/route.h>
92 #include <net/pfil.h>
93 #include <net/vnet.h>
94 
95 #include <netinet/in.h>
96 #include <netinet/in_var.h>
97 #include <netinet/ip_var.h>
98 #include <netinet6/in6_var.h>
99 #include <netinet/ip6.h>
100 #include <netinet/icmp6.h>
101 #include <netinet6/ip6_var.h>
102 #include <netinet/in_pcb.h>
103 #include <netinet/tcp_var.h>
104 #include <netinet6/nd6.h>
105 
106 #ifdef IPSEC
107 #include <netipsec/ipsec.h>
108 #include <netipsec/ipsec6.h>
109 #include <netipsec/key.h>
110 #include <netinet6/ip6_ipsec.h>
111 #endif /* IPSEC */
112 #ifdef SCTP
113 #include <netinet/sctp.h>
114 #include <netinet/sctp_crc32.h>
115 #endif
116 
117 #include <netinet6/ip6protosw.h>
118 #include <netinet6/scope6_var.h>
119 
120 #ifdef FLOWTABLE
121 #include <net/flowtable.h>
122 #endif
123 
124 extern int in6_mcast_loop;
125 
126 struct ip6_exthdrs {
127 	struct mbuf *ip6e_ip6;
128 	struct mbuf *ip6e_hbh;
129 	struct mbuf *ip6e_dest1;
130 	struct mbuf *ip6e_rthdr;
131 	struct mbuf *ip6e_dest2;
132 };
133 
134 static int ip6_pcbopt(int, u_char *, int, struct ip6_pktopts **,
135 			   struct ucred *, int);
136 static int ip6_pcbopts(struct ip6_pktopts **, struct mbuf *,
137 	struct socket *, struct sockopt *);
138 static int ip6_getpcbopt(struct ip6_pktopts *, int, struct sockopt *);
139 static int ip6_setpktopt(int, u_char *, int, struct ip6_pktopts *,
140 	struct ucred *, int, int, int);
141 
142 static int ip6_copyexthdr(struct mbuf **, caddr_t, int);
143 static int ip6_insertfraghdr(struct mbuf *, struct mbuf *, int,
144 	struct ip6_frag **);
145 static int ip6_insert_jumboopt(struct ip6_exthdrs *, u_int32_t);
146 static int ip6_splithdr(struct mbuf *, struct ip6_exthdrs *);
147 static int ip6_getpmtu(struct route_in6 *, struct route_in6 *,
148 	struct ifnet *, struct in6_addr *, u_long *, int *, u_int);
149 static int copypktopts(struct ip6_pktopts *, struct ip6_pktopts *, int);
150 
151 
152 /*
153  * Make an extension header from option data.  hp is the source, and
154  * mp is the destination.
155  */
156 #define MAKE_EXTHDR(hp, mp)						\
157     do {								\
158 	if (hp) {							\
159 		struct ip6_ext *eh = (struct ip6_ext *)(hp);		\
160 		error = ip6_copyexthdr((mp), (caddr_t)(hp),		\
161 		    ((eh)->ip6e_len + 1) << 3);				\
162 		if (error)						\
163 			goto freehdrs;					\
164 	}								\
165     } while (/*CONSTCOND*/ 0)
166 
167 /*
168  * Form a chain of extension headers.
169  * m is the extension header mbuf
170  * mp is the previous mbuf in the chain
171  * p is the next header
172  * i is the type of option.
173  */
174 #define MAKE_CHAIN(m, mp, p, i)\
175     do {\
176 	if (m) {\
177 		if (!hdrsplit) \
178 			panic("assumption failed: hdr not split"); \
179 		*mtod((m), u_char *) = *(p);\
180 		*(p) = (i);\
181 		p = mtod((m), u_char *);\
182 		(m)->m_next = (mp)->m_next;\
183 		(mp)->m_next = (m);\
184 		(mp) = (m);\
185 	}\
186     } while (/*CONSTCOND*/ 0)
187 
188 static void
189 in6_delayed_cksum(struct mbuf *m, uint32_t plen, u_short offset)
190 {
191 	u_short csum;
192 
193 	csum = in_cksum_skip(m, offset + plen, offset);
194 	if (m->m_pkthdr.csum_flags & CSUM_UDP_IPV6 && csum == 0)
195 		csum = 0xffff;
196 	offset += m->m_pkthdr.csum_data;	/* checksum offset */
197 
198 	if (offset + sizeof(u_short) > m->m_len) {
199 		printf("%s: delayed m_pullup, m->len: %d plen %u off %u "
200 		    "csum_flags=%b\n", __func__, m->m_len, plen, offset,
201 		    (int)m->m_pkthdr.csum_flags, CSUM_BITS);
202 		/*
203 		 * XXX this should not happen, but if it does, the correct
204 		 * behavior may be to insert the checksum in the appropriate
205 		 * next mbuf in the chain.
206 		 */
207 		return;
208 	}
209 	*(u_short *)(m->m_data + offset) = csum;
210 }
211 
212 /*
213  * IP6 output. The packet in mbuf chain m contains a skeletal IP6
214  * header (with pri, len, nxt, hlim, src, dst).
215  * This function may modify ver and hlim only.
216  * The mbuf chain containing the packet will be freed.
217  * The mbuf opt, if present, will not be freed.
218  * If route_in6 ro is present and has ro_rt initialized, route lookup would be
219  * skipped and ro->ro_rt would be used. If ro is present but ro->ro_rt is NULL,
220  * then result of route lookup is stored in ro->ro_rt.
221  *
222  * type of "mtu": rt_mtu is u_long, ifnet.ifr_mtu is int, and
223  * nd_ifinfo.linkmtu is u_int32_t.  so we use u_long to hold largest one,
224  * which is rt_mtu.
225  *
226  * ifpp - XXX: just for statistics
227  */
228 int
229 ip6_output(struct mbuf *m0, struct ip6_pktopts *opt,
230     struct route_in6 *ro, int flags, struct ip6_moptions *im6o,
231     struct ifnet **ifpp, struct inpcb *inp)
232 {
233 	struct ip6_hdr *ip6, *mhip6;
234 	struct ifnet *ifp, *origifp;
235 	struct mbuf *m = m0;
236 	struct mbuf *mprev = NULL;
237 	int hlen, tlen, len, off;
238 	struct route_in6 ip6route;
239 	struct rtentry *rt = NULL;
240 	struct sockaddr_in6 *dst, src_sa, dst_sa;
241 	struct in6_addr odst;
242 	int error = 0;
243 	struct in6_ifaddr *ia = NULL;
244 	u_long mtu;
245 	int alwaysfrag, dontfrag;
246 	u_int32_t optlen = 0, plen = 0, unfragpartlen = 0;
247 	struct ip6_exthdrs exthdrs;
248 	struct in6_addr finaldst, src0, dst0;
249 	u_int32_t zone;
250 	struct route_in6 *ro_pmtu = NULL;
251 	int hdrsplit = 0;
252 	int needipsec = 0;
253 	int sw_csum, tso;
254 #ifdef IPSEC
255 	struct ipsec_output_state state;
256 	struct ip6_rthdr *rh = NULL;
257 	int needipsectun = 0;
258 	int segleft_org = 0;
259 	struct secpolicy *sp = NULL;
260 #endif /* IPSEC */
261 	struct m_tag *fwd_tag = NULL;
262 
263 	ip6 = mtod(m, struct ip6_hdr *);
264 	if (ip6 == NULL) {
265 		printf ("ip6 is NULL");
266 		goto bad;
267 	}
268 
269 	if (inp != NULL)
270 		M_SETFIB(m, inp->inp_inc.inc_fibnum);
271 
272 	finaldst = ip6->ip6_dst;
273 	bzero(&exthdrs, sizeof(exthdrs));
274 	if (opt) {
275 		/* Hop-by-Hop options header */
276 		MAKE_EXTHDR(opt->ip6po_hbh, &exthdrs.ip6e_hbh);
277 		/* Destination options header(1st part) */
278 		if (opt->ip6po_rthdr) {
279 			/*
280 			 * Destination options header(1st part)
281 			 * This only makes sense with a routing header.
282 			 * See Section 9.2 of RFC 3542.
283 			 * Disabling this part just for MIP6 convenience is
284 			 * a bad idea.  We need to think carefully about a
285 			 * way to make the advanced API coexist with MIP6
286 			 * options, which might automatically be inserted in
287 			 * the kernel.
288 			 */
289 			MAKE_EXTHDR(opt->ip6po_dest1, &exthdrs.ip6e_dest1);
290 		}
291 		/* Routing header */
292 		MAKE_EXTHDR(opt->ip6po_rthdr, &exthdrs.ip6e_rthdr);
293 		/* Destination options header(2nd part) */
294 		MAKE_EXTHDR(opt->ip6po_dest2, &exthdrs.ip6e_dest2);
295 	}
296 
297 #ifdef IPSEC
298 	/*
299 	 * IPSec checking which handles several cases.
300 	 * FAST IPSEC: We re-injected the packet.
301 	 */
302 	switch(ip6_ipsec_output(&m, inp, &flags, &error, &ifp, &sp))
303 	{
304 	case 1:                 /* Bad packet */
305 		goto freehdrs;
306 	case -1:                /* Do IPSec */
307 		needipsec = 1;
308 		/*
309 		 * Do delayed checksums now, as we may send before returning.
310 		 */
311 		if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
312 			plen = m->m_pkthdr.len - sizeof(*ip6);
313 			in6_delayed_cksum(m, plen, sizeof(struct ip6_hdr));
314 			m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA_IPV6;
315 		}
316 #ifdef SCTP
317 		if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6) {
318 			sctp_delayed_cksum(m, sizeof(struct ip6_hdr));
319 			m->m_pkthdr.csum_flags &= ~CSUM_SCTP_IPV6;
320 		}
321 #endif
322 	case 0:                 /* No IPSec */
323 	default:
324 		break;
325 	}
326 #endif /* IPSEC */
327 
328 	/*
329 	 * Calculate the total length of the extension header chain.
330 	 * Keep the length of the unfragmentable part for fragmentation.
331 	 */
332 	optlen = 0;
333 	if (exthdrs.ip6e_hbh)
334 		optlen += exthdrs.ip6e_hbh->m_len;
335 	if (exthdrs.ip6e_dest1)
336 		optlen += exthdrs.ip6e_dest1->m_len;
337 	if (exthdrs.ip6e_rthdr)
338 		optlen += exthdrs.ip6e_rthdr->m_len;
339 	unfragpartlen = optlen + sizeof(struct ip6_hdr);
340 
341 	/* NOTE: we don't add AH/ESP length here. do that later. */
342 	if (exthdrs.ip6e_dest2)
343 		optlen += exthdrs.ip6e_dest2->m_len;
344 
345 	/*
346 	 * If we need IPsec, or there is at least one extension header,
347 	 * separate IP6 header from the payload.
348 	 */
349 	if ((needipsec || optlen) && !hdrsplit) {
350 		if ((error = ip6_splithdr(m, &exthdrs)) != 0) {
351 			m = NULL;
352 			goto freehdrs;
353 		}
354 		m = exthdrs.ip6e_ip6;
355 		hdrsplit++;
356 	}
357 
358 	/* adjust pointer */
359 	ip6 = mtod(m, struct ip6_hdr *);
360 
361 	/* adjust mbuf packet header length */
362 	m->m_pkthdr.len += optlen;
363 	plen = m->m_pkthdr.len - sizeof(*ip6);
364 
365 	/* If this is a jumbo payload, insert a jumbo payload option. */
366 	if (plen > IPV6_MAXPACKET) {
367 		if (!hdrsplit) {
368 			if ((error = ip6_splithdr(m, &exthdrs)) != 0) {
369 				m = NULL;
370 				goto freehdrs;
371 			}
372 			m = exthdrs.ip6e_ip6;
373 			hdrsplit++;
374 		}
375 		/* adjust pointer */
376 		ip6 = mtod(m, struct ip6_hdr *);
377 		if ((error = ip6_insert_jumboopt(&exthdrs, plen)) != 0)
378 			goto freehdrs;
379 		ip6->ip6_plen = 0;
380 	} else
381 		ip6->ip6_plen = htons(plen);
382 
383 	/*
384 	 * Concatenate headers and fill in next header fields.
385 	 * Here we have, on "m"
386 	 *	IPv6 payload
387 	 * and we insert headers accordingly.  Finally, we should be getting:
388 	 *	IPv6 hbh dest1 rthdr ah* [esp* dest2 payload]
389 	 *
390 	 * during the header composing process, "m" points to IPv6 header.
391 	 * "mprev" points to an extension header prior to esp.
392 	 */
393 	u_char *nexthdrp = &ip6->ip6_nxt;
394 	mprev = m;
395 
396 	/*
397 	 * we treat dest2 specially.  this makes IPsec processing
398 	 * much easier.  the goal here is to make mprev point the
399 	 * mbuf prior to dest2.
400 	 *
401 	 * result: IPv6 dest2 payload
402 	 * m and mprev will point to IPv6 header.
403 	 */
404 	if (exthdrs.ip6e_dest2) {
405 		if (!hdrsplit)
406 			panic("assumption failed: hdr not split");
407 		exthdrs.ip6e_dest2->m_next = m->m_next;
408 		m->m_next = exthdrs.ip6e_dest2;
409 		*mtod(exthdrs.ip6e_dest2, u_char *) = ip6->ip6_nxt;
410 		ip6->ip6_nxt = IPPROTO_DSTOPTS;
411 	}
412 
413 	/*
414 	 * result: IPv6 hbh dest1 rthdr dest2 payload
415 	 * m will point to IPv6 header.  mprev will point to the
416 	 * extension header prior to dest2 (rthdr in the above case).
417 	 */
418 	MAKE_CHAIN(exthdrs.ip6e_hbh, mprev, nexthdrp, IPPROTO_HOPOPTS);
419 	MAKE_CHAIN(exthdrs.ip6e_dest1, mprev, nexthdrp,
420 		   IPPROTO_DSTOPTS);
421 	MAKE_CHAIN(exthdrs.ip6e_rthdr, mprev, nexthdrp,
422 		   IPPROTO_ROUTING);
423 
424 #ifdef IPSEC
425 	if (!needipsec)
426 		goto skip_ipsec2;
427 
428 	/*
429 	 * pointers after IPsec headers are not valid any more.
430 	 * other pointers need a great care too.
431 	 * (IPsec routines should not mangle mbufs prior to AH/ESP)
432 	 */
433 	exthdrs.ip6e_dest2 = NULL;
434 
435 	if (exthdrs.ip6e_rthdr) {
436 		rh = mtod(exthdrs.ip6e_rthdr, struct ip6_rthdr *);
437 		segleft_org = rh->ip6r_segleft;
438 		rh->ip6r_segleft = 0;
439 	}
440 
441 	bzero(&state, sizeof(state));
442 	state.m = m;
443 	error = ipsec6_output_trans(&state, nexthdrp, mprev, sp, flags,
444 				    &needipsectun);
445 	m = state.m;
446 	if (error == EJUSTRETURN) {
447 		/*
448 		 * We had a SP with a level of 'use' and no SA. We
449 		 * will just continue to process the packet without
450 		 * IPsec processing.
451 		 */
452 		;
453 	} else if (error) {
454 		/* mbuf is already reclaimed in ipsec6_output_trans. */
455 		m = NULL;
456 		switch (error) {
457 		case EHOSTUNREACH:
458 		case ENETUNREACH:
459 		case EMSGSIZE:
460 		case ENOBUFS:
461 		case ENOMEM:
462 			break;
463 		default:
464 			printf("[%s:%d] (ipsec): error code %d\n",
465 			    __func__, __LINE__, error);
466 			/* FALLTHROUGH */
467 		case ENOENT:
468 			/* don't show these error codes to the user */
469 			error = 0;
470 			break;
471 		}
472 		goto bad;
473 	} else if (!needipsectun) {
474 		/*
475 		 * In the FAST IPSec case we have already
476 		 * re-injected the packet and it has been freed
477 		 * by the ipsec_done() function.  So, just clean
478 		 * up after ourselves.
479 		 */
480 		m = NULL;
481 		goto done;
482 	}
483 	if (exthdrs.ip6e_rthdr) {
484 		/* ah6_output doesn't modify mbuf chain */
485 		rh->ip6r_segleft = segleft_org;
486 	}
487 skip_ipsec2:;
488 #endif /* IPSEC */
489 
490 	/*
491 	 * If there is a routing header, discard the packet.
492 	 */
493 	if (exthdrs.ip6e_rthdr) {
494 		 error = EINVAL;
495 		 goto bad;
496 	}
497 
498 	/* Source address validation */
499 	if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) &&
500 	    (flags & IPV6_UNSPECSRC) == 0) {
501 		error = EOPNOTSUPP;
502 		IP6STAT_INC(ip6s_badscope);
503 		goto bad;
504 	}
505 	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_src)) {
506 		error = EOPNOTSUPP;
507 		IP6STAT_INC(ip6s_badscope);
508 		goto bad;
509 	}
510 
511 	IP6STAT_INC(ip6s_localout);
512 
513 	/*
514 	 * Route packet.
515 	 */
516 	if (ro == 0) {
517 		ro = &ip6route;
518 		bzero((caddr_t)ro, sizeof(*ro));
519 	}
520 	ro_pmtu = ro;
521 	if (opt && opt->ip6po_rthdr)
522 		ro = &opt->ip6po_route;
523 	dst = (struct sockaddr_in6 *)&ro->ro_dst;
524 #ifdef FLOWTABLE
525 	if (ro->ro_rt == NULL)
526 		(void )flowtable_lookup(AF_INET6, m, (struct route *)ro);
527 #endif
528 again:
529 	/*
530 	 * if specified, try to fill in the traffic class field.
531 	 * do not override if a non-zero value is already set.
532 	 * we check the diffserv field and the ecn field separately.
533 	 */
534 	if (opt && opt->ip6po_tclass >= 0) {
535 		int mask = 0;
536 
537 		if ((ip6->ip6_flow & htonl(0xfc << 20)) == 0)
538 			mask |= 0xfc;
539 		if ((ip6->ip6_flow & htonl(0x03 << 20)) == 0)
540 			mask |= 0x03;
541 		if (mask != 0)
542 			ip6->ip6_flow |= htonl((opt->ip6po_tclass & mask) << 20);
543 	}
544 
545 	/* fill in or override the hop limit field, if necessary. */
546 	if (opt && opt->ip6po_hlim != -1)
547 		ip6->ip6_hlim = opt->ip6po_hlim & 0xff;
548 	else if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
549 		if (im6o != NULL)
550 			ip6->ip6_hlim = im6o->im6o_multicast_hlim;
551 		else
552 			ip6->ip6_hlim = V_ip6_defmcasthlim;
553 	}
554 
555 #ifdef IPSEC
556 	/*
557 	 * We may re-inject packets into the stack here.
558 	 */
559 	if (needipsec && needipsectun) {
560 		struct ipsec_output_state state;
561 
562 		/*
563 		 * All the extension headers will become inaccessible
564 		 * (since they can be encrypted).
565 		 * Don't panic, we need no more updates to extension headers
566 		 * on inner IPv6 packet (since they are now encapsulated).
567 		 *
568 		 * IPv6 [ESP|AH] IPv6 [extension headers] payload
569 		 */
570 		bzero(&exthdrs, sizeof(exthdrs));
571 		exthdrs.ip6e_ip6 = m;
572 
573 		bzero(&state, sizeof(state));
574 		state.m = m;
575 		state.ro = (struct route *)ro;
576 		state.dst = (struct sockaddr *)dst;
577 
578 		error = ipsec6_output_tunnel(&state, sp, flags);
579 
580 		m = state.m;
581 		ro = (struct route_in6 *)state.ro;
582 		dst = (struct sockaddr_in6 *)state.dst;
583 		if (error == EJUSTRETURN) {
584 			/*
585 			 * We had a SP with a level of 'use' and no SA. We
586 			 * will just continue to process the packet without
587 			 * IPsec processing.
588 			 */
589 			;
590 		} else if (error) {
591 			/* mbuf is already reclaimed in ipsec6_output_tunnel. */
592 			m0 = m = NULL;
593 			m = NULL;
594 			switch (error) {
595 			case EHOSTUNREACH:
596 			case ENETUNREACH:
597 			case EMSGSIZE:
598 			case ENOBUFS:
599 			case ENOMEM:
600 				break;
601 			default:
602 				printf("[%s:%d] (ipsec): error code %d\n",
603 				    __func__, __LINE__, error);
604 				/* FALLTHROUGH */
605 			case ENOENT:
606 				/* don't show these error codes to the user */
607 				error = 0;
608 				break;
609 			}
610 			goto bad;
611 		} else {
612 			/*
613 			 * In the FAST IPSec case we have already
614 			 * re-injected the packet and it has been freed
615 			 * by the ipsec_done() function.  So, just clean
616 			 * up after ourselves.
617 			 */
618 			m = NULL;
619 			goto done;
620 		}
621 
622 		exthdrs.ip6e_ip6 = m;
623 	}
624 #endif /* IPSEC */
625 
626 	/* adjust pointer */
627 	ip6 = mtod(m, struct ip6_hdr *);
628 
629 	if (ro->ro_rt && fwd_tag == NULL) {
630 		rt = ro->ro_rt;
631 		ifp = ro->ro_rt->rt_ifp;
632 	} else {
633 		if (fwd_tag == NULL) {
634 			bzero(&dst_sa, sizeof(dst_sa));
635 			dst_sa.sin6_family = AF_INET6;
636 			dst_sa.sin6_len = sizeof(dst_sa);
637 			dst_sa.sin6_addr = ip6->ip6_dst;
638 		}
639 		error = in6_selectroute_fib(&dst_sa, opt, im6o, ro, &ifp,
640 		    &rt, inp ? inp->inp_inc.inc_fibnum : M_GETFIB(m));
641 		if (error != 0) {
642 			if (ifp != NULL)
643 				in6_ifstat_inc(ifp, ifs6_out_discard);
644 			goto bad;
645 		}
646 	}
647 	if (rt == NULL) {
648 		/*
649 		 * If in6_selectroute() does not return a route entry,
650 		 * dst may not have been updated.
651 		 */
652 		*dst = dst_sa;	/* XXX */
653 	}
654 
655 	/*
656 	 * then rt (for unicast) and ifp must be non-NULL valid values.
657 	 */
658 	if ((flags & IPV6_FORWARDING) == 0) {
659 		/* XXX: the FORWARDING flag can be set for mrouting. */
660 		in6_ifstat_inc(ifp, ifs6_out_request);
661 	}
662 	if (rt != NULL) {
663 		ia = (struct in6_ifaddr *)(rt->rt_ifa);
664 		counter_u64_add(rt->rt_pksent, 1);
665 	}
666 
667 
668 	/*
669 	 * The outgoing interface must be in the zone of source and
670 	 * destination addresses.
671 	 */
672 	origifp = ifp;
673 
674 	src0 = ip6->ip6_src;
675 	if (in6_setscope(&src0, origifp, &zone))
676 		goto badscope;
677 	bzero(&src_sa, sizeof(src_sa));
678 	src_sa.sin6_family = AF_INET6;
679 	src_sa.sin6_len = sizeof(src_sa);
680 	src_sa.sin6_addr = ip6->ip6_src;
681 	if (sa6_recoverscope(&src_sa) || zone != src_sa.sin6_scope_id)
682 		goto badscope;
683 
684 	dst0 = ip6->ip6_dst;
685 	if (in6_setscope(&dst0, origifp, &zone))
686 		goto badscope;
687 	/* re-initialize to be sure */
688 	bzero(&dst_sa, sizeof(dst_sa));
689 	dst_sa.sin6_family = AF_INET6;
690 	dst_sa.sin6_len = sizeof(dst_sa);
691 	dst_sa.sin6_addr = ip6->ip6_dst;
692 	if (sa6_recoverscope(&dst_sa) || zone != dst_sa.sin6_scope_id) {
693 		goto badscope;
694 	}
695 
696 	/* We should use ia_ifp to support the case of
697 	 * sending packets to an address of our own.
698 	 */
699 	if (ia != NULL && ia->ia_ifp)
700 		ifp = ia->ia_ifp;
701 
702 	/* scope check is done. */
703 	goto routefound;
704 
705   badscope:
706 	IP6STAT_INC(ip6s_badscope);
707 	in6_ifstat_inc(origifp, ifs6_out_discard);
708 	if (error == 0)
709 		error = EHOSTUNREACH; /* XXX */
710 	goto bad;
711 
712   routefound:
713 	if (rt && !IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
714 		if (opt && opt->ip6po_nextroute.ro_rt) {
715 			/*
716 			 * The nexthop is explicitly specified by the
717 			 * application.  We assume the next hop is an IPv6
718 			 * address.
719 			 */
720 			dst = (struct sockaddr_in6 *)opt->ip6po_nexthop;
721 		}
722 		else if ((rt->rt_flags & RTF_GATEWAY))
723 			dst = (struct sockaddr_in6 *)rt->rt_gateway;
724 	}
725 
726 	if (!IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
727 		m->m_flags &= ~(M_BCAST | M_MCAST); /* just in case */
728 	} else {
729 		m->m_flags = (m->m_flags & ~M_BCAST) | M_MCAST;
730 		in6_ifstat_inc(ifp, ifs6_out_mcast);
731 		/*
732 		 * Confirm that the outgoing interface supports multicast.
733 		 */
734 		if (!(ifp->if_flags & IFF_MULTICAST)) {
735 			IP6STAT_INC(ip6s_noroute);
736 			in6_ifstat_inc(ifp, ifs6_out_discard);
737 			error = ENETUNREACH;
738 			goto bad;
739 		}
740 		if ((im6o == NULL && in6_mcast_loop) ||
741 		    (im6o && im6o->im6o_multicast_loop)) {
742 			/*
743 			 * Loop back multicast datagram if not expressly
744 			 * forbidden to do so, even if we have not joined
745 			 * the address; protocols will filter it later,
746 			 * thus deferring a hash lookup and lock acquisition
747 			 * at the expense of an m_copym().
748 			 */
749 			ip6_mloopback(ifp, m, dst);
750 		} else {
751 			/*
752 			 * If we are acting as a multicast router, perform
753 			 * multicast forwarding as if the packet had just
754 			 * arrived on the interface to which we are about
755 			 * to send.  The multicast forwarding function
756 			 * recursively calls this function, using the
757 			 * IPV6_FORWARDING flag to prevent infinite recursion.
758 			 *
759 			 * Multicasts that are looped back by ip6_mloopback(),
760 			 * above, will be forwarded by the ip6_input() routine,
761 			 * if necessary.
762 			 */
763 			if (V_ip6_mrouter && (flags & IPV6_FORWARDING) == 0) {
764 				/*
765 				 * XXX: ip6_mforward expects that rcvif is NULL
766 				 * when it is called from the originating path.
767 				 * However, it may not always be the case.
768 				 */
769 				m->m_pkthdr.rcvif = NULL;
770 				if (ip6_mforward(ip6, ifp, m) != 0) {
771 					m_freem(m);
772 					goto done;
773 				}
774 			}
775 		}
776 		/*
777 		 * Multicasts with a hoplimit of zero may be looped back,
778 		 * above, but must not be transmitted on a network.
779 		 * Also, multicasts addressed to the loopback interface
780 		 * are not sent -- the above call to ip6_mloopback() will
781 		 * loop back a copy if this host actually belongs to the
782 		 * destination group on the loopback interface.
783 		 */
784 		if (ip6->ip6_hlim == 0 || (ifp->if_flags & IFF_LOOPBACK) ||
785 		    IN6_IS_ADDR_MC_INTFACELOCAL(&ip6->ip6_dst)) {
786 			m_freem(m);
787 			goto done;
788 		}
789 	}
790 
791 	/*
792 	 * Fill the outgoing inteface to tell the upper layer
793 	 * to increment per-interface statistics.
794 	 */
795 	if (ifpp)
796 		*ifpp = ifp;
797 
798 	/* Determine path MTU. */
799 	if ((error = ip6_getpmtu(ro_pmtu, ro, ifp, &finaldst, &mtu,
800 	    &alwaysfrag, inp ? inp->inp_inc.inc_fibnum : M_GETFIB(m))) != 0)
801 		goto bad;
802 
803 	/*
804 	 * The caller of this function may specify to use the minimum MTU
805 	 * in some cases.
806 	 * An advanced API option (IPV6_USE_MIN_MTU) can also override MTU
807 	 * setting.  The logic is a bit complicated; by default, unicast
808 	 * packets will follow path MTU while multicast packets will be sent at
809 	 * the minimum MTU.  If IP6PO_MINMTU_ALL is specified, all packets
810 	 * including unicast ones will be sent at the minimum MTU.  Multicast
811 	 * packets will always be sent at the minimum MTU unless
812 	 * IP6PO_MINMTU_DISABLE is explicitly specified.
813 	 * See RFC 3542 for more details.
814 	 */
815 	if (mtu > IPV6_MMTU) {
816 		if ((flags & IPV6_MINMTU))
817 			mtu = IPV6_MMTU;
818 		else if (opt && opt->ip6po_minmtu == IP6PO_MINMTU_ALL)
819 			mtu = IPV6_MMTU;
820 		else if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) &&
821 			 (opt == NULL ||
822 			  opt->ip6po_minmtu != IP6PO_MINMTU_DISABLE)) {
823 			mtu = IPV6_MMTU;
824 		}
825 	}
826 
827 	/*
828 	 * clear embedded scope identifiers if necessary.
829 	 * in6_clearscope will touch the addresses only when necessary.
830 	 */
831 	in6_clearscope(&ip6->ip6_src);
832 	in6_clearscope(&ip6->ip6_dst);
833 
834 	/*
835 	 * If the outgoing packet contains a hop-by-hop options header,
836 	 * it must be examined and processed even by the source node.
837 	 * (RFC 2460, section 4.)
838 	 */
839 	if (exthdrs.ip6e_hbh) {
840 		struct ip6_hbh *hbh = mtod(exthdrs.ip6e_hbh, struct ip6_hbh *);
841 		u_int32_t dummy; /* XXX unused */
842 		u_int32_t plen = 0; /* XXX: ip6_process will check the value */
843 
844 #ifdef DIAGNOSTIC
845 		if ((hbh->ip6h_len + 1) << 3 > exthdrs.ip6e_hbh->m_len)
846 			panic("ip6e_hbh is not contiguous");
847 #endif
848 		/*
849 		 *  XXX: if we have to send an ICMPv6 error to the sender,
850 		 *       we need the M_LOOP flag since icmp6_error() expects
851 		 *       the IPv6 and the hop-by-hop options header are
852 		 *       contiguous unless the flag is set.
853 		 */
854 		m->m_flags |= M_LOOP;
855 		m->m_pkthdr.rcvif = ifp;
856 		if (ip6_process_hopopts(m, (u_int8_t *)(hbh + 1),
857 		    ((hbh->ip6h_len + 1) << 3) - sizeof(struct ip6_hbh),
858 		    &dummy, &plen) < 0) {
859 			/* m was already freed at this point */
860 			error = EINVAL;/* better error? */
861 			goto done;
862 		}
863 		m->m_flags &= ~M_LOOP; /* XXX */
864 		m->m_pkthdr.rcvif = NULL;
865 	}
866 
867 	/* Jump over all PFIL processing if hooks are not active. */
868 	if (!PFIL_HOOKED(&V_inet6_pfil_hook))
869 		goto passout;
870 
871 	odst = ip6->ip6_dst;
872 	/* Run through list of hooks for output packets. */
873 	error = pfil_run_hooks(&V_inet6_pfil_hook, &m, ifp, PFIL_OUT, inp);
874 	if (error != 0 || m == NULL)
875 		goto done;
876 	ip6 = mtod(m, struct ip6_hdr *);
877 
878 	/* See if destination IP address was changed by packet filter. */
879 	if (!IN6_ARE_ADDR_EQUAL(&odst, &ip6->ip6_dst)) {
880 		m->m_flags |= M_SKIP_FIREWALL;
881 		/* If destination is now ourself drop to ip6_input(). */
882 		if (in6_localip(&ip6->ip6_dst)) {
883 			m->m_flags |= M_FASTFWD_OURS;
884 			if (m->m_pkthdr.rcvif == NULL)
885 				m->m_pkthdr.rcvif = V_loif;
886 			if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
887 				m->m_pkthdr.csum_flags |=
888 				    CSUM_DATA_VALID_IPV6 | CSUM_PSEUDO_HDR;
889 				m->m_pkthdr.csum_data = 0xffff;
890 			}
891 #ifdef SCTP
892 			if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6)
893 				m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
894 #endif
895 			error = netisr_queue(NETISR_IPV6, m);
896 			goto done;
897 		} else
898 			goto again;	/* Redo the routing table lookup. */
899 	}
900 
901 	/* See if local, if yes, send it to netisr. */
902 	if (m->m_flags & M_FASTFWD_OURS) {
903 		if (m->m_pkthdr.rcvif == NULL)
904 			m->m_pkthdr.rcvif = V_loif;
905 		if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
906 			m->m_pkthdr.csum_flags |=
907 			    CSUM_DATA_VALID_IPV6 | CSUM_PSEUDO_HDR;
908 			m->m_pkthdr.csum_data = 0xffff;
909 		}
910 #ifdef SCTP
911 		if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6)
912 			m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
913 #endif
914 		error = netisr_queue(NETISR_IPV6, m);
915 		goto done;
916 	}
917 	/* Or forward to some other address? */
918 	if ((m->m_flags & M_IP6_NEXTHOP) &&
919 	    (fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL)) != NULL) {
920 		dst = (struct sockaddr_in6 *)&ro->ro_dst;
921 		bcopy((fwd_tag+1), &dst_sa, sizeof(struct sockaddr_in6));
922 		m->m_flags |= M_SKIP_FIREWALL;
923 		m->m_flags &= ~M_IP6_NEXTHOP;
924 		m_tag_delete(m, fwd_tag);
925 		goto again;
926 	}
927 
928 passout:
929 	/*
930 	 * Send the packet to the outgoing interface.
931 	 * If necessary, do IPv6 fragmentation before sending.
932 	 *
933 	 * the logic here is rather complex:
934 	 * 1: normal case (dontfrag == 0, alwaysfrag == 0)
935 	 * 1-a:	send as is if tlen <= path mtu
936 	 * 1-b:	fragment if tlen > path mtu
937 	 *
938 	 * 2: if user asks us not to fragment (dontfrag == 1)
939 	 * 2-a:	send as is if tlen <= interface mtu
940 	 * 2-b:	error if tlen > interface mtu
941 	 *
942 	 * 3: if we always need to attach fragment header (alwaysfrag == 1)
943 	 *	always fragment
944 	 *
945 	 * 4: if dontfrag == 1 && alwaysfrag == 1
946 	 *	error, as we cannot handle this conflicting request
947 	 */
948 	sw_csum = m->m_pkthdr.csum_flags;
949 	if (!hdrsplit) {
950 		tso = ((sw_csum & ifp->if_hwassist & CSUM_TSO) != 0) ? 1 : 0;
951 		sw_csum &= ~ifp->if_hwassist;
952 	} else
953 		tso = 0;
954 	/*
955 	 * If we added extension headers, we will not do TSO and calculate the
956 	 * checksums ourselves for now.
957 	 * XXX-BZ  Need a framework to know when the NIC can handle it, even
958 	 * with ext. hdrs.
959 	 */
960 	if (sw_csum & CSUM_DELAY_DATA_IPV6) {
961 		sw_csum &= ~CSUM_DELAY_DATA_IPV6;
962 		in6_delayed_cksum(m, plen, sizeof(struct ip6_hdr));
963 	}
964 #ifdef SCTP
965 	if (sw_csum & CSUM_SCTP_IPV6) {
966 		sw_csum &= ~CSUM_SCTP_IPV6;
967 		sctp_delayed_cksum(m, sizeof(struct ip6_hdr));
968 	}
969 #endif
970 	m->m_pkthdr.csum_flags &= ifp->if_hwassist;
971 	tlen = m->m_pkthdr.len;
972 
973 	if ((opt && (opt->ip6po_flags & IP6PO_DONTFRAG)) || tso)
974 		dontfrag = 1;
975 	else
976 		dontfrag = 0;
977 	if (dontfrag && alwaysfrag) {	/* case 4 */
978 		/* conflicting request - can't transmit */
979 		error = EMSGSIZE;
980 		goto bad;
981 	}
982 	if (dontfrag && tlen > IN6_LINKMTU(ifp) && !tso) {	/* case 2-b */
983 		/*
984 		 * Even if the DONTFRAG option is specified, we cannot send the
985 		 * packet when the data length is larger than the MTU of the
986 		 * outgoing interface.
987 		 * Notify the error by sending IPV6_PATHMTU ancillary data as
988 		 * well as returning an error code (the latter is not described
989 		 * in the API spec.)
990 		 */
991 		u_int32_t mtu32;
992 		struct ip6ctlparam ip6cp;
993 
994 		mtu32 = (u_int32_t)mtu;
995 		bzero(&ip6cp, sizeof(ip6cp));
996 		ip6cp.ip6c_cmdarg = (void *)&mtu32;
997 		pfctlinput2(PRC_MSGSIZE, (struct sockaddr *)&ro_pmtu->ro_dst,
998 		    (void *)&ip6cp);
999 
1000 		error = EMSGSIZE;
1001 		goto bad;
1002 	}
1003 
1004 	/*
1005 	 * transmit packet without fragmentation
1006 	 */
1007 	if (dontfrag || (!alwaysfrag && tlen <= mtu)) {	/* case 1-a and 2-a */
1008 		struct in6_ifaddr *ia6;
1009 
1010 		ip6 = mtod(m, struct ip6_hdr *);
1011 		ia6 = in6_ifawithifp(ifp, &ip6->ip6_src);
1012 		if (ia6) {
1013 			/* Record statistics for this interface address. */
1014 			counter_u64_add(ia6->ia_ifa.ifa_opackets, 1);
1015 			counter_u64_add(ia6->ia_ifa.ifa_obytes,
1016 			    m->m_pkthdr.len);
1017 			ifa_free(&ia6->ia_ifa);
1018 		}
1019 		error = nd6_output(ifp, origifp, m, dst, ro->ro_rt);
1020 		goto done;
1021 	}
1022 
1023 	/*
1024 	 * try to fragment the packet.  case 1-b and 3
1025 	 */
1026 	if (mtu < IPV6_MMTU) {
1027 		/* path MTU cannot be less than IPV6_MMTU */
1028 		error = EMSGSIZE;
1029 		in6_ifstat_inc(ifp, ifs6_out_fragfail);
1030 		goto bad;
1031 	} else if (ip6->ip6_plen == 0) {
1032 		/* jumbo payload cannot be fragmented */
1033 		error = EMSGSIZE;
1034 		in6_ifstat_inc(ifp, ifs6_out_fragfail);
1035 		goto bad;
1036 	} else {
1037 		struct mbuf **mnext, *m_frgpart;
1038 		struct ip6_frag *ip6f;
1039 		u_int32_t id = htonl(ip6_randomid());
1040 		u_char nextproto;
1041 
1042 		int qslots = ifp->if_snd.ifq_maxlen - ifp->if_snd.ifq_len;
1043 
1044 		/*
1045 		 * Too large for the destination or interface;
1046 		 * fragment if possible.
1047 		 * Must be able to put at least 8 bytes per fragment.
1048 		 */
1049 		hlen = unfragpartlen;
1050 		if (mtu > IPV6_MAXPACKET)
1051 			mtu = IPV6_MAXPACKET;
1052 
1053 		len = (mtu - hlen - sizeof(struct ip6_frag)) & ~7;
1054 		if (len < 8) {
1055 			error = EMSGSIZE;
1056 			in6_ifstat_inc(ifp, ifs6_out_fragfail);
1057 			goto bad;
1058 		}
1059 
1060 		/*
1061 		 * Verify that we have any chance at all of being able to queue
1062 		 *      the packet or packet fragments
1063 		 */
1064 		if (qslots <= 0 || ((u_int)qslots * (mtu - hlen)
1065 		    < tlen  /* - hlen */)) {
1066 			error = ENOBUFS;
1067 			IP6STAT_INC(ip6s_odropped);
1068 			goto bad;
1069 		}
1070 
1071 
1072 		/*
1073 		 * If the interface will not calculate checksums on
1074 		 * fragmented packets, then do it here.
1075 		 * XXX-BZ handle the hw offloading case.  Need flags.
1076 		 */
1077 		if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
1078 			in6_delayed_cksum(m, plen, hlen);
1079 			m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA_IPV6;
1080 		}
1081 #ifdef SCTP
1082 		if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6) {
1083 			sctp_delayed_cksum(m, hlen);
1084 			m->m_pkthdr.csum_flags &= ~CSUM_SCTP_IPV6;
1085 		}
1086 #endif
1087 		mnext = &m->m_nextpkt;
1088 
1089 		/*
1090 		 * Change the next header field of the last header in the
1091 		 * unfragmentable part.
1092 		 */
1093 		if (exthdrs.ip6e_rthdr) {
1094 			nextproto = *mtod(exthdrs.ip6e_rthdr, u_char *);
1095 			*mtod(exthdrs.ip6e_rthdr, u_char *) = IPPROTO_FRAGMENT;
1096 		} else if (exthdrs.ip6e_dest1) {
1097 			nextproto = *mtod(exthdrs.ip6e_dest1, u_char *);
1098 			*mtod(exthdrs.ip6e_dest1, u_char *) = IPPROTO_FRAGMENT;
1099 		} else if (exthdrs.ip6e_hbh) {
1100 			nextproto = *mtod(exthdrs.ip6e_hbh, u_char *);
1101 			*mtod(exthdrs.ip6e_hbh, u_char *) = IPPROTO_FRAGMENT;
1102 		} else {
1103 			nextproto = ip6->ip6_nxt;
1104 			ip6->ip6_nxt = IPPROTO_FRAGMENT;
1105 		}
1106 
1107 		/*
1108 		 * Loop through length of segment after first fragment,
1109 		 * make new header and copy data of each part and link onto
1110 		 * chain.
1111 		 */
1112 		m0 = m;
1113 		for (off = hlen; off < tlen; off += len) {
1114 			m = m_gethdr(M_NOWAIT, MT_DATA);
1115 			if (!m) {
1116 				error = ENOBUFS;
1117 				IP6STAT_INC(ip6s_odropped);
1118 				goto sendorfree;
1119 			}
1120 			m->m_flags = m0->m_flags & M_COPYFLAGS;
1121 			*mnext = m;
1122 			mnext = &m->m_nextpkt;
1123 			m->m_data += max_linkhdr;
1124 			mhip6 = mtod(m, struct ip6_hdr *);
1125 			*mhip6 = *ip6;
1126 			m->m_len = sizeof(*mhip6);
1127 			error = ip6_insertfraghdr(m0, m, hlen, &ip6f);
1128 			if (error) {
1129 				IP6STAT_INC(ip6s_odropped);
1130 				goto sendorfree;
1131 			}
1132 			ip6f->ip6f_offlg = htons((u_short)((off - hlen) & ~7));
1133 			if (off + len >= tlen)
1134 				len = tlen - off;
1135 			else
1136 				ip6f->ip6f_offlg |= IP6F_MORE_FRAG;
1137 			mhip6->ip6_plen = htons((u_short)(len + hlen +
1138 			    sizeof(*ip6f) - sizeof(struct ip6_hdr)));
1139 			if ((m_frgpart = m_copy(m0, off, len)) == 0) {
1140 				error = ENOBUFS;
1141 				IP6STAT_INC(ip6s_odropped);
1142 				goto sendorfree;
1143 			}
1144 			m_cat(m, m_frgpart);
1145 			m->m_pkthdr.len = len + hlen + sizeof(*ip6f);
1146 			m->m_pkthdr.fibnum = m0->m_pkthdr.fibnum;
1147 			m->m_pkthdr.rcvif = NULL;
1148 			ip6f->ip6f_reserved = 0;
1149 			ip6f->ip6f_ident = id;
1150 			ip6f->ip6f_nxt = nextproto;
1151 			IP6STAT_INC(ip6s_ofragments);
1152 			in6_ifstat_inc(ifp, ifs6_out_fragcreat);
1153 		}
1154 
1155 		in6_ifstat_inc(ifp, ifs6_out_fragok);
1156 	}
1157 
1158 	/*
1159 	 * Remove leading garbages.
1160 	 */
1161 sendorfree:
1162 	m = m0->m_nextpkt;
1163 	m0->m_nextpkt = 0;
1164 	m_freem(m0);
1165 	for (m0 = m; m; m = m0) {
1166 		m0 = m->m_nextpkt;
1167 		m->m_nextpkt = 0;
1168 		if (error == 0) {
1169 			/* Record statistics for this interface address. */
1170 			if (ia) {
1171 				counter_u64_add(ia->ia_ifa.ifa_opackets, 1);
1172 				counter_u64_add(ia->ia_ifa.ifa_obytes,
1173 				    m->m_pkthdr.len);
1174 			}
1175 			error = nd6_output(ifp, origifp, m, dst, ro->ro_rt);
1176 		} else
1177 			m_freem(m);
1178 	}
1179 
1180 	if (error == 0)
1181 		IP6STAT_INC(ip6s_fragmented);
1182 
1183 done:
1184 	if (ro == &ip6route)
1185 		RO_RTFREE(ro);
1186 	if (ro_pmtu == &ip6route)
1187 		RO_RTFREE(ro_pmtu);
1188 #ifdef IPSEC
1189 	if (sp != NULL)
1190 		KEY_FREESP(&sp);
1191 #endif
1192 
1193 	return (error);
1194 
1195 freehdrs:
1196 	m_freem(exthdrs.ip6e_hbh);	/* m_freem will check if mbuf is 0 */
1197 	m_freem(exthdrs.ip6e_dest1);
1198 	m_freem(exthdrs.ip6e_rthdr);
1199 	m_freem(exthdrs.ip6e_dest2);
1200 	/* FALLTHROUGH */
1201 bad:
1202 	if (m)
1203 		m_freem(m);
1204 	goto done;
1205 }
1206 
1207 static int
1208 ip6_copyexthdr(struct mbuf **mp, caddr_t hdr, int hlen)
1209 {
1210 	struct mbuf *m;
1211 
1212 	if (hlen > MCLBYTES)
1213 		return (ENOBUFS); /* XXX */
1214 
1215 	if (hlen > MLEN)
1216 		m = m_getcl(M_NOWAIT, MT_DATA, 0);
1217 	else
1218 		m = m_get(M_NOWAIT, MT_DATA);
1219 	if (m == NULL)
1220 		return (ENOBUFS);
1221 	m->m_len = hlen;
1222 	if (hdr)
1223 		bcopy(hdr, mtod(m, caddr_t), hlen);
1224 
1225 	*mp = m;
1226 	return (0);
1227 }
1228 
1229 /*
1230  * Insert jumbo payload option.
1231  */
1232 static int
1233 ip6_insert_jumboopt(struct ip6_exthdrs *exthdrs, u_int32_t plen)
1234 {
1235 	struct mbuf *mopt;
1236 	u_char *optbuf;
1237 	u_int32_t v;
1238 
1239 #define JUMBOOPTLEN	8	/* length of jumbo payload option and padding */
1240 
1241 	/*
1242 	 * If there is no hop-by-hop options header, allocate new one.
1243 	 * If there is one but it doesn't have enough space to store the
1244 	 * jumbo payload option, allocate a cluster to store the whole options.
1245 	 * Otherwise, use it to store the options.
1246 	 */
1247 	if (exthdrs->ip6e_hbh == 0) {
1248 		mopt = m_get(M_NOWAIT, MT_DATA);
1249 		if (mopt == NULL)
1250 			return (ENOBUFS);
1251 		mopt->m_len = JUMBOOPTLEN;
1252 		optbuf = mtod(mopt, u_char *);
1253 		optbuf[1] = 0;	/* = ((JUMBOOPTLEN) >> 3) - 1 */
1254 		exthdrs->ip6e_hbh = mopt;
1255 	} else {
1256 		struct ip6_hbh *hbh;
1257 
1258 		mopt = exthdrs->ip6e_hbh;
1259 		if (M_TRAILINGSPACE(mopt) < JUMBOOPTLEN) {
1260 			/*
1261 			 * XXX assumption:
1262 			 * - exthdrs->ip6e_hbh is not referenced from places
1263 			 *   other than exthdrs.
1264 			 * - exthdrs->ip6e_hbh is not an mbuf chain.
1265 			 */
1266 			int oldoptlen = mopt->m_len;
1267 			struct mbuf *n;
1268 
1269 			/*
1270 			 * XXX: give up if the whole (new) hbh header does
1271 			 * not fit even in an mbuf cluster.
1272 			 */
1273 			if (oldoptlen + JUMBOOPTLEN > MCLBYTES)
1274 				return (ENOBUFS);
1275 
1276 			/*
1277 			 * As a consequence, we must always prepare a cluster
1278 			 * at this point.
1279 			 */
1280 			n = m_getcl(M_NOWAIT, MT_DATA, 0);
1281 			if (n == NULL)
1282 				return (ENOBUFS);
1283 			n->m_len = oldoptlen + JUMBOOPTLEN;
1284 			bcopy(mtod(mopt, caddr_t), mtod(n, caddr_t),
1285 			    oldoptlen);
1286 			optbuf = mtod(n, caddr_t) + oldoptlen;
1287 			m_freem(mopt);
1288 			mopt = exthdrs->ip6e_hbh = n;
1289 		} else {
1290 			optbuf = mtod(mopt, u_char *) + mopt->m_len;
1291 			mopt->m_len += JUMBOOPTLEN;
1292 		}
1293 		optbuf[0] = IP6OPT_PADN;
1294 		optbuf[1] = 1;
1295 
1296 		/*
1297 		 * Adjust the header length according to the pad and
1298 		 * the jumbo payload option.
1299 		 */
1300 		hbh = mtod(mopt, struct ip6_hbh *);
1301 		hbh->ip6h_len += (JUMBOOPTLEN >> 3);
1302 	}
1303 
1304 	/* fill in the option. */
1305 	optbuf[2] = IP6OPT_JUMBO;
1306 	optbuf[3] = 4;
1307 	v = (u_int32_t)htonl(plen + JUMBOOPTLEN);
1308 	bcopy(&v, &optbuf[4], sizeof(u_int32_t));
1309 
1310 	/* finally, adjust the packet header length */
1311 	exthdrs->ip6e_ip6->m_pkthdr.len += JUMBOOPTLEN;
1312 
1313 	return (0);
1314 #undef JUMBOOPTLEN
1315 }
1316 
1317 /*
1318  * Insert fragment header and copy unfragmentable header portions.
1319  */
1320 static int
1321 ip6_insertfraghdr(struct mbuf *m0, struct mbuf *m, int hlen,
1322     struct ip6_frag **frghdrp)
1323 {
1324 	struct mbuf *n, *mlast;
1325 
1326 	if (hlen > sizeof(struct ip6_hdr)) {
1327 		n = m_copym(m0, sizeof(struct ip6_hdr),
1328 		    hlen - sizeof(struct ip6_hdr), M_NOWAIT);
1329 		if (n == 0)
1330 			return (ENOBUFS);
1331 		m->m_next = n;
1332 	} else
1333 		n = m;
1334 
1335 	/* Search for the last mbuf of unfragmentable part. */
1336 	for (mlast = n; mlast->m_next; mlast = mlast->m_next)
1337 		;
1338 
1339 	if ((mlast->m_flags & M_EXT) == 0 &&
1340 	    M_TRAILINGSPACE(mlast) >= sizeof(struct ip6_frag)) {
1341 		/* use the trailing space of the last mbuf for the fragment hdr */
1342 		*frghdrp = (struct ip6_frag *)(mtod(mlast, caddr_t) +
1343 		    mlast->m_len);
1344 		mlast->m_len += sizeof(struct ip6_frag);
1345 		m->m_pkthdr.len += sizeof(struct ip6_frag);
1346 	} else {
1347 		/* allocate a new mbuf for the fragment header */
1348 		struct mbuf *mfrg;
1349 
1350 		mfrg = m_get(M_NOWAIT, MT_DATA);
1351 		if (mfrg == NULL)
1352 			return (ENOBUFS);
1353 		mfrg->m_len = sizeof(struct ip6_frag);
1354 		*frghdrp = mtod(mfrg, struct ip6_frag *);
1355 		mlast->m_next = mfrg;
1356 	}
1357 
1358 	return (0);
1359 }
1360 
1361 static int
1362 ip6_getpmtu(struct route_in6 *ro_pmtu, struct route_in6 *ro,
1363     struct ifnet *ifp, struct in6_addr *dst, u_long *mtup,
1364     int *alwaysfragp, u_int fibnum)
1365 {
1366 	u_int32_t mtu = 0;
1367 	int alwaysfrag = 0;
1368 	int error = 0;
1369 
1370 	if (ro_pmtu != ro) {
1371 		/* The first hop and the final destination may differ. */
1372 		struct sockaddr_in6 *sa6_dst =
1373 		    (struct sockaddr_in6 *)&ro_pmtu->ro_dst;
1374 		if (ro_pmtu->ro_rt &&
1375 		    ((ro_pmtu->ro_rt->rt_flags & RTF_UP) == 0 ||
1376 		     !IN6_ARE_ADDR_EQUAL(&sa6_dst->sin6_addr, dst))) {
1377 			RTFREE(ro_pmtu->ro_rt);
1378 			ro_pmtu->ro_rt = (struct rtentry *)NULL;
1379 		}
1380 		if (ro_pmtu->ro_rt == NULL) {
1381 			bzero(sa6_dst, sizeof(*sa6_dst));
1382 			sa6_dst->sin6_family = AF_INET6;
1383 			sa6_dst->sin6_len = sizeof(struct sockaddr_in6);
1384 			sa6_dst->sin6_addr = *dst;
1385 
1386 			in6_rtalloc(ro_pmtu, fibnum);
1387 		}
1388 	}
1389 	if (ro_pmtu->ro_rt) {
1390 		u_int32_t ifmtu;
1391 		struct in_conninfo inc;
1392 
1393 		bzero(&inc, sizeof(inc));
1394 		inc.inc_flags |= INC_ISIPV6;
1395 		inc.inc6_faddr = *dst;
1396 
1397 		if (ifp == NULL)
1398 			ifp = ro_pmtu->ro_rt->rt_ifp;
1399 		ifmtu = IN6_LINKMTU(ifp);
1400 		mtu = tcp_hc_getmtu(&inc);
1401 		if (mtu)
1402 			mtu = min(mtu, ro_pmtu->ro_rt->rt_mtu);
1403 		else
1404 			mtu = ro_pmtu->ro_rt->rt_mtu;
1405 		if (mtu == 0)
1406 			mtu = ifmtu;
1407 		else if (mtu < IPV6_MMTU) {
1408 			/*
1409 			 * RFC2460 section 5, last paragraph:
1410 			 * if we record ICMPv6 too big message with
1411 			 * mtu < IPV6_MMTU, transmit packets sized IPV6_MMTU
1412 			 * or smaller, with framgent header attached.
1413 			 * (fragment header is needed regardless from the
1414 			 * packet size, for translators to identify packets)
1415 			 */
1416 			alwaysfrag = 1;
1417 			mtu = IPV6_MMTU;
1418 		} else if (mtu > ifmtu) {
1419 			/*
1420 			 * The MTU on the route is larger than the MTU on
1421 			 * the interface!  This shouldn't happen, unless the
1422 			 * MTU of the interface has been changed after the
1423 			 * interface was brought up.  Change the MTU in the
1424 			 * route to match the interface MTU (as long as the
1425 			 * field isn't locked).
1426 			 */
1427 			mtu = ifmtu;
1428 			ro_pmtu->ro_rt->rt_mtu = mtu;
1429 		}
1430 	} else if (ifp) {
1431 		mtu = IN6_LINKMTU(ifp);
1432 	} else
1433 		error = EHOSTUNREACH; /* XXX */
1434 
1435 	*mtup = mtu;
1436 	if (alwaysfragp)
1437 		*alwaysfragp = alwaysfrag;
1438 	return (error);
1439 }
1440 
1441 /*
1442  * IP6 socket option processing.
1443  */
1444 int
1445 ip6_ctloutput(struct socket *so, struct sockopt *sopt)
1446 {
1447 	int optdatalen, uproto;
1448 	void *optdata;
1449 	struct inpcb *in6p = sotoinpcb(so);
1450 	int error, optval;
1451 	int level, op, optname;
1452 	int optlen;
1453 	struct thread *td;
1454 
1455 	level = sopt->sopt_level;
1456 	op = sopt->sopt_dir;
1457 	optname = sopt->sopt_name;
1458 	optlen = sopt->sopt_valsize;
1459 	td = sopt->sopt_td;
1460 	error = 0;
1461 	optval = 0;
1462 	uproto = (int)so->so_proto->pr_protocol;
1463 
1464 	if (level != IPPROTO_IPV6) {
1465 		error = EINVAL;
1466 
1467 		if (sopt->sopt_level == SOL_SOCKET &&
1468 		    sopt->sopt_dir == SOPT_SET) {
1469 			switch (sopt->sopt_name) {
1470 			case SO_REUSEADDR:
1471 				INP_WLOCK(in6p);
1472 				if ((so->so_options & SO_REUSEADDR) != 0)
1473 					in6p->inp_flags2 |= INP_REUSEADDR;
1474 				else
1475 					in6p->inp_flags2 &= ~INP_REUSEADDR;
1476 				INP_WUNLOCK(in6p);
1477 				error = 0;
1478 				break;
1479 			case SO_REUSEPORT:
1480 				INP_WLOCK(in6p);
1481 				if ((so->so_options & SO_REUSEPORT) != 0)
1482 					in6p->inp_flags2 |= INP_REUSEPORT;
1483 				else
1484 					in6p->inp_flags2 &= ~INP_REUSEPORT;
1485 				INP_WUNLOCK(in6p);
1486 				error = 0;
1487 				break;
1488 			case SO_SETFIB:
1489 				INP_WLOCK(in6p);
1490 				in6p->inp_inc.inc_fibnum = so->so_fibnum;
1491 				INP_WUNLOCK(in6p);
1492 				error = 0;
1493 				break;
1494 			default:
1495 				break;
1496 			}
1497 		}
1498 	} else {		/* level == IPPROTO_IPV6 */
1499 		switch (op) {
1500 
1501 		case SOPT_SET:
1502 			switch (optname) {
1503 			case IPV6_2292PKTOPTIONS:
1504 #ifdef IPV6_PKTOPTIONS
1505 			case IPV6_PKTOPTIONS:
1506 #endif
1507 			{
1508 				struct mbuf *m;
1509 
1510 				error = soopt_getm(sopt, &m); /* XXX */
1511 				if (error != 0)
1512 					break;
1513 				error = soopt_mcopyin(sopt, m); /* XXX */
1514 				if (error != 0)
1515 					break;
1516 				error = ip6_pcbopts(&in6p->in6p_outputopts,
1517 						    m, so, sopt);
1518 				m_freem(m); /* XXX */
1519 				break;
1520 			}
1521 
1522 			/*
1523 			 * Use of some Hop-by-Hop options or some
1524 			 * Destination options, might require special
1525 			 * privilege.  That is, normal applications
1526 			 * (without special privilege) might be forbidden
1527 			 * from setting certain options in outgoing packets,
1528 			 * and might never see certain options in received
1529 			 * packets. [RFC 2292 Section 6]
1530 			 * KAME specific note:
1531 			 *  KAME prevents non-privileged users from sending or
1532 			 *  receiving ANY hbh/dst options in order to avoid
1533 			 *  overhead of parsing options in the kernel.
1534 			 */
1535 			case IPV6_RECVHOPOPTS:
1536 			case IPV6_RECVDSTOPTS:
1537 			case IPV6_RECVRTHDRDSTOPTS:
1538 				if (td != NULL) {
1539 					error = priv_check(td,
1540 					    PRIV_NETINET_SETHDROPTS);
1541 					if (error)
1542 						break;
1543 				}
1544 				/* FALLTHROUGH */
1545 			case IPV6_UNICAST_HOPS:
1546 			case IPV6_HOPLIMIT:
1547 			case IPV6_FAITH:
1548 
1549 			case IPV6_RECVPKTINFO:
1550 			case IPV6_RECVHOPLIMIT:
1551 			case IPV6_RECVRTHDR:
1552 			case IPV6_RECVPATHMTU:
1553 			case IPV6_RECVTCLASS:
1554 			case IPV6_V6ONLY:
1555 			case IPV6_AUTOFLOWLABEL:
1556 			case IPV6_BINDANY:
1557 				if (optname == IPV6_BINDANY && td != NULL) {
1558 					error = priv_check(td,
1559 					    PRIV_NETINET_BINDANY);
1560 					if (error)
1561 						break;
1562 				}
1563 
1564 				if (optlen != sizeof(int)) {
1565 					error = EINVAL;
1566 					break;
1567 				}
1568 				error = sooptcopyin(sopt, &optval,
1569 					sizeof optval, sizeof optval);
1570 				if (error)
1571 					break;
1572 				switch (optname) {
1573 
1574 				case IPV6_UNICAST_HOPS:
1575 					if (optval < -1 || optval >= 256)
1576 						error = EINVAL;
1577 					else {
1578 						/* -1 = kernel default */
1579 						in6p->in6p_hops = optval;
1580 						if ((in6p->inp_vflag &
1581 						     INP_IPV4) != 0)
1582 							in6p->inp_ip_ttl = optval;
1583 					}
1584 					break;
1585 #define OPTSET(bit) \
1586 do { \
1587 	INP_WLOCK(in6p); \
1588 	if (optval) \
1589 		in6p->inp_flags |= (bit); \
1590 	else \
1591 		in6p->inp_flags &= ~(bit); \
1592 	INP_WUNLOCK(in6p); \
1593 } while (/*CONSTCOND*/ 0)
1594 #define OPTSET2292(bit) \
1595 do { \
1596 	INP_WLOCK(in6p); \
1597 	in6p->inp_flags |= IN6P_RFC2292; \
1598 	if (optval) \
1599 		in6p->inp_flags |= (bit); \
1600 	else \
1601 		in6p->inp_flags &= ~(bit); \
1602 	INP_WUNLOCK(in6p); \
1603 } while (/*CONSTCOND*/ 0)
1604 #define OPTBIT(bit) (in6p->inp_flags & (bit) ? 1 : 0)
1605 
1606 				case IPV6_RECVPKTINFO:
1607 					/* cannot mix with RFC2292 */
1608 					if (OPTBIT(IN6P_RFC2292)) {
1609 						error = EINVAL;
1610 						break;
1611 					}
1612 					OPTSET(IN6P_PKTINFO);
1613 					break;
1614 
1615 				case IPV6_HOPLIMIT:
1616 				{
1617 					struct ip6_pktopts **optp;
1618 
1619 					/* cannot mix with RFC2292 */
1620 					if (OPTBIT(IN6P_RFC2292)) {
1621 						error = EINVAL;
1622 						break;
1623 					}
1624 					optp = &in6p->in6p_outputopts;
1625 					error = ip6_pcbopt(IPV6_HOPLIMIT,
1626 					    (u_char *)&optval, sizeof(optval),
1627 					    optp, (td != NULL) ? td->td_ucred :
1628 					    NULL, uproto);
1629 					break;
1630 				}
1631 
1632 				case IPV6_RECVHOPLIMIT:
1633 					/* cannot mix with RFC2292 */
1634 					if (OPTBIT(IN6P_RFC2292)) {
1635 						error = EINVAL;
1636 						break;
1637 					}
1638 					OPTSET(IN6P_HOPLIMIT);
1639 					break;
1640 
1641 				case IPV6_RECVHOPOPTS:
1642 					/* cannot mix with RFC2292 */
1643 					if (OPTBIT(IN6P_RFC2292)) {
1644 						error = EINVAL;
1645 						break;
1646 					}
1647 					OPTSET(IN6P_HOPOPTS);
1648 					break;
1649 
1650 				case IPV6_RECVDSTOPTS:
1651 					/* cannot mix with RFC2292 */
1652 					if (OPTBIT(IN6P_RFC2292)) {
1653 						error = EINVAL;
1654 						break;
1655 					}
1656 					OPTSET(IN6P_DSTOPTS);
1657 					break;
1658 
1659 				case IPV6_RECVRTHDRDSTOPTS:
1660 					/* cannot mix with RFC2292 */
1661 					if (OPTBIT(IN6P_RFC2292)) {
1662 						error = EINVAL;
1663 						break;
1664 					}
1665 					OPTSET(IN6P_RTHDRDSTOPTS);
1666 					break;
1667 
1668 				case IPV6_RECVRTHDR:
1669 					/* cannot mix with RFC2292 */
1670 					if (OPTBIT(IN6P_RFC2292)) {
1671 						error = EINVAL;
1672 						break;
1673 					}
1674 					OPTSET(IN6P_RTHDR);
1675 					break;
1676 
1677 				case IPV6_FAITH:
1678 					OPTSET(INP_FAITH);
1679 					break;
1680 
1681 				case IPV6_RECVPATHMTU:
1682 					/*
1683 					 * We ignore this option for TCP
1684 					 * sockets.
1685 					 * (RFC3542 leaves this case
1686 					 * unspecified.)
1687 					 */
1688 					if (uproto != IPPROTO_TCP)
1689 						OPTSET(IN6P_MTU);
1690 					break;
1691 
1692 				case IPV6_V6ONLY:
1693 					/*
1694 					 * make setsockopt(IPV6_V6ONLY)
1695 					 * available only prior to bind(2).
1696 					 * see ipng mailing list, Jun 22 2001.
1697 					 */
1698 					if (in6p->inp_lport ||
1699 					    !IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_laddr)) {
1700 						error = EINVAL;
1701 						break;
1702 					}
1703 					OPTSET(IN6P_IPV6_V6ONLY);
1704 					if (optval)
1705 						in6p->inp_vflag &= ~INP_IPV4;
1706 					else
1707 						in6p->inp_vflag |= INP_IPV4;
1708 					break;
1709 				case IPV6_RECVTCLASS:
1710 					/* cannot mix with RFC2292 XXX */
1711 					if (OPTBIT(IN6P_RFC2292)) {
1712 						error = EINVAL;
1713 						break;
1714 					}
1715 					OPTSET(IN6P_TCLASS);
1716 					break;
1717 				case IPV6_AUTOFLOWLABEL:
1718 					OPTSET(IN6P_AUTOFLOWLABEL);
1719 					break;
1720 
1721 				case IPV6_BINDANY:
1722 					OPTSET(INP_BINDANY);
1723 					break;
1724 				}
1725 				break;
1726 
1727 			case IPV6_TCLASS:
1728 			case IPV6_DONTFRAG:
1729 			case IPV6_USE_MIN_MTU:
1730 			case IPV6_PREFER_TEMPADDR:
1731 				if (optlen != sizeof(optval)) {
1732 					error = EINVAL;
1733 					break;
1734 				}
1735 				error = sooptcopyin(sopt, &optval,
1736 					sizeof optval, sizeof optval);
1737 				if (error)
1738 					break;
1739 				{
1740 					struct ip6_pktopts **optp;
1741 					optp = &in6p->in6p_outputopts;
1742 					error = ip6_pcbopt(optname,
1743 					    (u_char *)&optval, sizeof(optval),
1744 					    optp, (td != NULL) ? td->td_ucred :
1745 					    NULL, uproto);
1746 					break;
1747 				}
1748 
1749 			case IPV6_2292PKTINFO:
1750 			case IPV6_2292HOPLIMIT:
1751 			case IPV6_2292HOPOPTS:
1752 			case IPV6_2292DSTOPTS:
1753 			case IPV6_2292RTHDR:
1754 				/* RFC 2292 */
1755 				if (optlen != sizeof(int)) {
1756 					error = EINVAL;
1757 					break;
1758 				}
1759 				error = sooptcopyin(sopt, &optval,
1760 					sizeof optval, sizeof optval);
1761 				if (error)
1762 					break;
1763 				switch (optname) {
1764 				case IPV6_2292PKTINFO:
1765 					OPTSET2292(IN6P_PKTINFO);
1766 					break;
1767 				case IPV6_2292HOPLIMIT:
1768 					OPTSET2292(IN6P_HOPLIMIT);
1769 					break;
1770 				case IPV6_2292HOPOPTS:
1771 					/*
1772 					 * Check super-user privilege.
1773 					 * See comments for IPV6_RECVHOPOPTS.
1774 					 */
1775 					if (td != NULL) {
1776 						error = priv_check(td,
1777 						    PRIV_NETINET_SETHDROPTS);
1778 						if (error)
1779 							return (error);
1780 					}
1781 					OPTSET2292(IN6P_HOPOPTS);
1782 					break;
1783 				case IPV6_2292DSTOPTS:
1784 					if (td != NULL) {
1785 						error = priv_check(td,
1786 						    PRIV_NETINET_SETHDROPTS);
1787 						if (error)
1788 							return (error);
1789 					}
1790 					OPTSET2292(IN6P_DSTOPTS|IN6P_RTHDRDSTOPTS); /* XXX */
1791 					break;
1792 				case IPV6_2292RTHDR:
1793 					OPTSET2292(IN6P_RTHDR);
1794 					break;
1795 				}
1796 				break;
1797 			case IPV6_PKTINFO:
1798 			case IPV6_HOPOPTS:
1799 			case IPV6_RTHDR:
1800 			case IPV6_DSTOPTS:
1801 			case IPV6_RTHDRDSTOPTS:
1802 			case IPV6_NEXTHOP:
1803 			{
1804 				/* new advanced API (RFC3542) */
1805 				u_char *optbuf;
1806 				u_char optbuf_storage[MCLBYTES];
1807 				int optlen;
1808 				struct ip6_pktopts **optp;
1809 
1810 				/* cannot mix with RFC2292 */
1811 				if (OPTBIT(IN6P_RFC2292)) {
1812 					error = EINVAL;
1813 					break;
1814 				}
1815 
1816 				/*
1817 				 * We only ensure valsize is not too large
1818 				 * here.  Further validation will be done
1819 				 * later.
1820 				 */
1821 				error = sooptcopyin(sopt, optbuf_storage,
1822 				    sizeof(optbuf_storage), 0);
1823 				if (error)
1824 					break;
1825 				optlen = sopt->sopt_valsize;
1826 				optbuf = optbuf_storage;
1827 				optp = &in6p->in6p_outputopts;
1828 				error = ip6_pcbopt(optname, optbuf, optlen,
1829 				    optp, (td != NULL) ? td->td_ucred : NULL,
1830 				    uproto);
1831 				break;
1832 			}
1833 #undef OPTSET
1834 
1835 			case IPV6_MULTICAST_IF:
1836 			case IPV6_MULTICAST_HOPS:
1837 			case IPV6_MULTICAST_LOOP:
1838 			case IPV6_JOIN_GROUP:
1839 			case IPV6_LEAVE_GROUP:
1840 			case IPV6_MSFILTER:
1841 			case MCAST_BLOCK_SOURCE:
1842 			case MCAST_UNBLOCK_SOURCE:
1843 			case MCAST_JOIN_GROUP:
1844 			case MCAST_LEAVE_GROUP:
1845 			case MCAST_JOIN_SOURCE_GROUP:
1846 			case MCAST_LEAVE_SOURCE_GROUP:
1847 				error = ip6_setmoptions(in6p, sopt);
1848 				break;
1849 
1850 			case IPV6_PORTRANGE:
1851 				error = sooptcopyin(sopt, &optval,
1852 				    sizeof optval, sizeof optval);
1853 				if (error)
1854 					break;
1855 
1856 				INP_WLOCK(in6p);
1857 				switch (optval) {
1858 				case IPV6_PORTRANGE_DEFAULT:
1859 					in6p->inp_flags &= ~(INP_LOWPORT);
1860 					in6p->inp_flags &= ~(INP_HIGHPORT);
1861 					break;
1862 
1863 				case IPV6_PORTRANGE_HIGH:
1864 					in6p->inp_flags &= ~(INP_LOWPORT);
1865 					in6p->inp_flags |= INP_HIGHPORT;
1866 					break;
1867 
1868 				case IPV6_PORTRANGE_LOW:
1869 					in6p->inp_flags &= ~(INP_HIGHPORT);
1870 					in6p->inp_flags |= INP_LOWPORT;
1871 					break;
1872 
1873 				default:
1874 					error = EINVAL;
1875 					break;
1876 				}
1877 				INP_WUNLOCK(in6p);
1878 				break;
1879 
1880 #ifdef IPSEC
1881 			case IPV6_IPSEC_POLICY:
1882 			{
1883 				caddr_t req;
1884 				struct mbuf *m;
1885 
1886 				if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */
1887 					break;
1888 				if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */
1889 					break;
1890 				req = mtod(m, caddr_t);
1891 				error = ipsec_set_policy(in6p, optname, req,
1892 				    m->m_len, (sopt->sopt_td != NULL) ?
1893 				    sopt->sopt_td->td_ucred : NULL);
1894 				m_freem(m);
1895 				break;
1896 			}
1897 #endif /* IPSEC */
1898 
1899 			default:
1900 				error = ENOPROTOOPT;
1901 				break;
1902 			}
1903 			break;
1904 
1905 		case SOPT_GET:
1906 			switch (optname) {
1907 
1908 			case IPV6_2292PKTOPTIONS:
1909 #ifdef IPV6_PKTOPTIONS
1910 			case IPV6_PKTOPTIONS:
1911 #endif
1912 				/*
1913 				 * RFC3542 (effectively) deprecated the
1914 				 * semantics of the 2292-style pktoptions.
1915 				 * Since it was not reliable in nature (i.e.,
1916 				 * applications had to expect the lack of some
1917 				 * information after all), it would make sense
1918 				 * to simplify this part by always returning
1919 				 * empty data.
1920 				 */
1921 				sopt->sopt_valsize = 0;
1922 				break;
1923 
1924 			case IPV6_RECVHOPOPTS:
1925 			case IPV6_RECVDSTOPTS:
1926 			case IPV6_RECVRTHDRDSTOPTS:
1927 			case IPV6_UNICAST_HOPS:
1928 			case IPV6_RECVPKTINFO:
1929 			case IPV6_RECVHOPLIMIT:
1930 			case IPV6_RECVRTHDR:
1931 			case IPV6_RECVPATHMTU:
1932 
1933 			case IPV6_FAITH:
1934 			case IPV6_V6ONLY:
1935 			case IPV6_PORTRANGE:
1936 			case IPV6_RECVTCLASS:
1937 			case IPV6_AUTOFLOWLABEL:
1938 			case IPV6_BINDANY:
1939 				switch (optname) {
1940 
1941 				case IPV6_RECVHOPOPTS:
1942 					optval = OPTBIT(IN6P_HOPOPTS);
1943 					break;
1944 
1945 				case IPV6_RECVDSTOPTS:
1946 					optval = OPTBIT(IN6P_DSTOPTS);
1947 					break;
1948 
1949 				case IPV6_RECVRTHDRDSTOPTS:
1950 					optval = OPTBIT(IN6P_RTHDRDSTOPTS);
1951 					break;
1952 
1953 				case IPV6_UNICAST_HOPS:
1954 					optval = in6p->in6p_hops;
1955 					break;
1956 
1957 				case IPV6_RECVPKTINFO:
1958 					optval = OPTBIT(IN6P_PKTINFO);
1959 					break;
1960 
1961 				case IPV6_RECVHOPLIMIT:
1962 					optval = OPTBIT(IN6P_HOPLIMIT);
1963 					break;
1964 
1965 				case IPV6_RECVRTHDR:
1966 					optval = OPTBIT(IN6P_RTHDR);
1967 					break;
1968 
1969 				case IPV6_RECVPATHMTU:
1970 					optval = OPTBIT(IN6P_MTU);
1971 					break;
1972 
1973 				case IPV6_FAITH:
1974 					optval = OPTBIT(INP_FAITH);
1975 					break;
1976 
1977 				case IPV6_V6ONLY:
1978 					optval = OPTBIT(IN6P_IPV6_V6ONLY);
1979 					break;
1980 
1981 				case IPV6_PORTRANGE:
1982 				    {
1983 					int flags;
1984 					flags = in6p->inp_flags;
1985 					if (flags & INP_HIGHPORT)
1986 						optval = IPV6_PORTRANGE_HIGH;
1987 					else if (flags & INP_LOWPORT)
1988 						optval = IPV6_PORTRANGE_LOW;
1989 					else
1990 						optval = 0;
1991 					break;
1992 				    }
1993 				case IPV6_RECVTCLASS:
1994 					optval = OPTBIT(IN6P_TCLASS);
1995 					break;
1996 
1997 				case IPV6_AUTOFLOWLABEL:
1998 					optval = OPTBIT(IN6P_AUTOFLOWLABEL);
1999 					break;
2000 
2001 				case IPV6_BINDANY:
2002 					optval = OPTBIT(INP_BINDANY);
2003 					break;
2004 				}
2005 				if (error)
2006 					break;
2007 				error = sooptcopyout(sopt, &optval,
2008 					sizeof optval);
2009 				break;
2010 
2011 			case IPV6_PATHMTU:
2012 			{
2013 				u_long pmtu = 0;
2014 				struct ip6_mtuinfo mtuinfo;
2015 				struct route_in6 sro;
2016 
2017 				bzero(&sro, sizeof(sro));
2018 
2019 				if (!(so->so_state & SS_ISCONNECTED))
2020 					return (ENOTCONN);
2021 				/*
2022 				 * XXX: we dot not consider the case of source
2023 				 * routing, or optional information to specify
2024 				 * the outgoing interface.
2025 				 */
2026 				error = ip6_getpmtu(&sro, NULL, NULL,
2027 				    &in6p->in6p_faddr, &pmtu, NULL,
2028 				    so->so_fibnum);
2029 				if (sro.ro_rt)
2030 					RTFREE(sro.ro_rt);
2031 				if (error)
2032 					break;
2033 				if (pmtu > IPV6_MAXPACKET)
2034 					pmtu = IPV6_MAXPACKET;
2035 
2036 				bzero(&mtuinfo, sizeof(mtuinfo));
2037 				mtuinfo.ip6m_mtu = (u_int32_t)pmtu;
2038 				optdata = (void *)&mtuinfo;
2039 				optdatalen = sizeof(mtuinfo);
2040 				error = sooptcopyout(sopt, optdata,
2041 				    optdatalen);
2042 				break;
2043 			}
2044 
2045 			case IPV6_2292PKTINFO:
2046 			case IPV6_2292HOPLIMIT:
2047 			case IPV6_2292HOPOPTS:
2048 			case IPV6_2292RTHDR:
2049 			case IPV6_2292DSTOPTS:
2050 				switch (optname) {
2051 				case IPV6_2292PKTINFO:
2052 					optval = OPTBIT(IN6P_PKTINFO);
2053 					break;
2054 				case IPV6_2292HOPLIMIT:
2055 					optval = OPTBIT(IN6P_HOPLIMIT);
2056 					break;
2057 				case IPV6_2292HOPOPTS:
2058 					optval = OPTBIT(IN6P_HOPOPTS);
2059 					break;
2060 				case IPV6_2292RTHDR:
2061 					optval = OPTBIT(IN6P_RTHDR);
2062 					break;
2063 				case IPV6_2292DSTOPTS:
2064 					optval = OPTBIT(IN6P_DSTOPTS|IN6P_RTHDRDSTOPTS);
2065 					break;
2066 				}
2067 				error = sooptcopyout(sopt, &optval,
2068 				    sizeof optval);
2069 				break;
2070 			case IPV6_PKTINFO:
2071 			case IPV6_HOPOPTS:
2072 			case IPV6_RTHDR:
2073 			case IPV6_DSTOPTS:
2074 			case IPV6_RTHDRDSTOPTS:
2075 			case IPV6_NEXTHOP:
2076 			case IPV6_TCLASS:
2077 			case IPV6_DONTFRAG:
2078 			case IPV6_USE_MIN_MTU:
2079 			case IPV6_PREFER_TEMPADDR:
2080 				error = ip6_getpcbopt(in6p->in6p_outputopts,
2081 				    optname, sopt);
2082 				break;
2083 
2084 			case IPV6_MULTICAST_IF:
2085 			case IPV6_MULTICAST_HOPS:
2086 			case IPV6_MULTICAST_LOOP:
2087 			case IPV6_MSFILTER:
2088 				error = ip6_getmoptions(in6p, sopt);
2089 				break;
2090 
2091 #ifdef IPSEC
2092 			case IPV6_IPSEC_POLICY:
2093 			  {
2094 				caddr_t req = NULL;
2095 				size_t len = 0;
2096 				struct mbuf *m = NULL;
2097 				struct mbuf **mp = &m;
2098 				size_t ovalsize = sopt->sopt_valsize;
2099 				caddr_t oval = (caddr_t)sopt->sopt_val;
2100 
2101 				error = soopt_getm(sopt, &m); /* XXX */
2102 				if (error != 0)
2103 					break;
2104 				error = soopt_mcopyin(sopt, m); /* XXX */
2105 				if (error != 0)
2106 					break;
2107 				sopt->sopt_valsize = ovalsize;
2108 				sopt->sopt_val = oval;
2109 				if (m) {
2110 					req = mtod(m, caddr_t);
2111 					len = m->m_len;
2112 				}
2113 				error = ipsec_get_policy(in6p, req, len, mp);
2114 				if (error == 0)
2115 					error = soopt_mcopyout(sopt, m); /* XXX */
2116 				if (error == 0 && m)
2117 					m_freem(m);
2118 				break;
2119 			  }
2120 #endif /* IPSEC */
2121 
2122 			default:
2123 				error = ENOPROTOOPT;
2124 				break;
2125 			}
2126 			break;
2127 		}
2128 	}
2129 	return (error);
2130 }
2131 
2132 int
2133 ip6_raw_ctloutput(struct socket *so, struct sockopt *sopt)
2134 {
2135 	int error = 0, optval, optlen;
2136 	const int icmp6off = offsetof(struct icmp6_hdr, icmp6_cksum);
2137 	struct inpcb *in6p = sotoinpcb(so);
2138 	int level, op, optname;
2139 
2140 	level = sopt->sopt_level;
2141 	op = sopt->sopt_dir;
2142 	optname = sopt->sopt_name;
2143 	optlen = sopt->sopt_valsize;
2144 
2145 	if (level != IPPROTO_IPV6) {
2146 		return (EINVAL);
2147 	}
2148 
2149 	switch (optname) {
2150 	case IPV6_CHECKSUM:
2151 		/*
2152 		 * For ICMPv6 sockets, no modification allowed for checksum
2153 		 * offset, permit "no change" values to help existing apps.
2154 		 *
2155 		 * RFC3542 says: "An attempt to set IPV6_CHECKSUM
2156 		 * for an ICMPv6 socket will fail."
2157 		 * The current behavior does not meet RFC3542.
2158 		 */
2159 		switch (op) {
2160 		case SOPT_SET:
2161 			if (optlen != sizeof(int)) {
2162 				error = EINVAL;
2163 				break;
2164 			}
2165 			error = sooptcopyin(sopt, &optval, sizeof(optval),
2166 					    sizeof(optval));
2167 			if (error)
2168 				break;
2169 			if ((optval % 2) != 0) {
2170 				/* the API assumes even offset values */
2171 				error = EINVAL;
2172 			} else if (so->so_proto->pr_protocol ==
2173 			    IPPROTO_ICMPV6) {
2174 				if (optval != icmp6off)
2175 					error = EINVAL;
2176 			} else
2177 				in6p->in6p_cksum = optval;
2178 			break;
2179 
2180 		case SOPT_GET:
2181 			if (so->so_proto->pr_protocol == IPPROTO_ICMPV6)
2182 				optval = icmp6off;
2183 			else
2184 				optval = in6p->in6p_cksum;
2185 
2186 			error = sooptcopyout(sopt, &optval, sizeof(optval));
2187 			break;
2188 
2189 		default:
2190 			error = EINVAL;
2191 			break;
2192 		}
2193 		break;
2194 
2195 	default:
2196 		error = ENOPROTOOPT;
2197 		break;
2198 	}
2199 
2200 	return (error);
2201 }
2202 
2203 /*
2204  * Set up IP6 options in pcb for insertion in output packets or
2205  * specifying behavior of outgoing packets.
2206  */
2207 static int
2208 ip6_pcbopts(struct ip6_pktopts **pktopt, struct mbuf *m,
2209     struct socket *so, struct sockopt *sopt)
2210 {
2211 	struct ip6_pktopts *opt = *pktopt;
2212 	int error = 0;
2213 	struct thread *td = sopt->sopt_td;
2214 
2215 	/* turn off any old options. */
2216 	if (opt) {
2217 #ifdef DIAGNOSTIC
2218 		if (opt->ip6po_pktinfo || opt->ip6po_nexthop ||
2219 		    opt->ip6po_hbh || opt->ip6po_dest1 || opt->ip6po_dest2 ||
2220 		    opt->ip6po_rhinfo.ip6po_rhi_rthdr)
2221 			printf("ip6_pcbopts: all specified options are cleared.\n");
2222 #endif
2223 		ip6_clearpktopts(opt, -1);
2224 	} else
2225 		opt = malloc(sizeof(*opt), M_IP6OPT, M_WAITOK);
2226 	*pktopt = NULL;
2227 
2228 	if (!m || m->m_len == 0) {
2229 		/*
2230 		 * Only turning off any previous options, regardless of
2231 		 * whether the opt is just created or given.
2232 		 */
2233 		free(opt, M_IP6OPT);
2234 		return (0);
2235 	}
2236 
2237 	/*  set options specified by user. */
2238 	if ((error = ip6_setpktopts(m, opt, NULL, (td != NULL) ?
2239 	    td->td_ucred : NULL, so->so_proto->pr_protocol)) != 0) {
2240 		ip6_clearpktopts(opt, -1); /* XXX: discard all options */
2241 		free(opt, M_IP6OPT);
2242 		return (error);
2243 	}
2244 	*pktopt = opt;
2245 	return (0);
2246 }
2247 
2248 /*
2249  * initialize ip6_pktopts.  beware that there are non-zero default values in
2250  * the struct.
2251  */
2252 void
2253 ip6_initpktopts(struct ip6_pktopts *opt)
2254 {
2255 
2256 	bzero(opt, sizeof(*opt));
2257 	opt->ip6po_hlim = -1;	/* -1 means default hop limit */
2258 	opt->ip6po_tclass = -1;	/* -1 means default traffic class */
2259 	opt->ip6po_minmtu = IP6PO_MINMTU_MCASTONLY;
2260 	opt->ip6po_prefer_tempaddr = IP6PO_TEMPADDR_SYSTEM;
2261 }
2262 
2263 static int
2264 ip6_pcbopt(int optname, u_char *buf, int len, struct ip6_pktopts **pktopt,
2265     struct ucred *cred, int uproto)
2266 {
2267 	struct ip6_pktopts *opt;
2268 
2269 	if (*pktopt == NULL) {
2270 		*pktopt = malloc(sizeof(struct ip6_pktopts), M_IP6OPT,
2271 		    M_WAITOK);
2272 		ip6_initpktopts(*pktopt);
2273 	}
2274 	opt = *pktopt;
2275 
2276 	return (ip6_setpktopt(optname, buf, len, opt, cred, 1, 0, uproto));
2277 }
2278 
2279 static int
2280 ip6_getpcbopt(struct ip6_pktopts *pktopt, int optname, struct sockopt *sopt)
2281 {
2282 	void *optdata = NULL;
2283 	int optdatalen = 0;
2284 	struct ip6_ext *ip6e;
2285 	int error = 0;
2286 	struct in6_pktinfo null_pktinfo;
2287 	int deftclass = 0, on;
2288 	int defminmtu = IP6PO_MINMTU_MCASTONLY;
2289 	int defpreftemp = IP6PO_TEMPADDR_SYSTEM;
2290 
2291 	switch (optname) {
2292 	case IPV6_PKTINFO:
2293 		if (pktopt && pktopt->ip6po_pktinfo)
2294 			optdata = (void *)pktopt->ip6po_pktinfo;
2295 		else {
2296 			/* XXX: we don't have to do this every time... */
2297 			bzero(&null_pktinfo, sizeof(null_pktinfo));
2298 			optdata = (void *)&null_pktinfo;
2299 		}
2300 		optdatalen = sizeof(struct in6_pktinfo);
2301 		break;
2302 	case IPV6_TCLASS:
2303 		if (pktopt && pktopt->ip6po_tclass >= 0)
2304 			optdata = (void *)&pktopt->ip6po_tclass;
2305 		else
2306 			optdata = (void *)&deftclass;
2307 		optdatalen = sizeof(int);
2308 		break;
2309 	case IPV6_HOPOPTS:
2310 		if (pktopt && pktopt->ip6po_hbh) {
2311 			optdata = (void *)pktopt->ip6po_hbh;
2312 			ip6e = (struct ip6_ext *)pktopt->ip6po_hbh;
2313 			optdatalen = (ip6e->ip6e_len + 1) << 3;
2314 		}
2315 		break;
2316 	case IPV6_RTHDR:
2317 		if (pktopt && pktopt->ip6po_rthdr) {
2318 			optdata = (void *)pktopt->ip6po_rthdr;
2319 			ip6e = (struct ip6_ext *)pktopt->ip6po_rthdr;
2320 			optdatalen = (ip6e->ip6e_len + 1) << 3;
2321 		}
2322 		break;
2323 	case IPV6_RTHDRDSTOPTS:
2324 		if (pktopt && pktopt->ip6po_dest1) {
2325 			optdata = (void *)pktopt->ip6po_dest1;
2326 			ip6e = (struct ip6_ext *)pktopt->ip6po_dest1;
2327 			optdatalen = (ip6e->ip6e_len + 1) << 3;
2328 		}
2329 		break;
2330 	case IPV6_DSTOPTS:
2331 		if (pktopt && pktopt->ip6po_dest2) {
2332 			optdata = (void *)pktopt->ip6po_dest2;
2333 			ip6e = (struct ip6_ext *)pktopt->ip6po_dest2;
2334 			optdatalen = (ip6e->ip6e_len + 1) << 3;
2335 		}
2336 		break;
2337 	case IPV6_NEXTHOP:
2338 		if (pktopt && pktopt->ip6po_nexthop) {
2339 			optdata = (void *)pktopt->ip6po_nexthop;
2340 			optdatalen = pktopt->ip6po_nexthop->sa_len;
2341 		}
2342 		break;
2343 	case IPV6_USE_MIN_MTU:
2344 		if (pktopt)
2345 			optdata = (void *)&pktopt->ip6po_minmtu;
2346 		else
2347 			optdata = (void *)&defminmtu;
2348 		optdatalen = sizeof(int);
2349 		break;
2350 	case IPV6_DONTFRAG:
2351 		if (pktopt && ((pktopt->ip6po_flags) & IP6PO_DONTFRAG))
2352 			on = 1;
2353 		else
2354 			on = 0;
2355 		optdata = (void *)&on;
2356 		optdatalen = sizeof(on);
2357 		break;
2358 	case IPV6_PREFER_TEMPADDR:
2359 		if (pktopt)
2360 			optdata = (void *)&pktopt->ip6po_prefer_tempaddr;
2361 		else
2362 			optdata = (void *)&defpreftemp;
2363 		optdatalen = sizeof(int);
2364 		break;
2365 	default:		/* should not happen */
2366 #ifdef DIAGNOSTIC
2367 		panic("ip6_getpcbopt: unexpected option\n");
2368 #endif
2369 		return (ENOPROTOOPT);
2370 	}
2371 
2372 	error = sooptcopyout(sopt, optdata, optdatalen);
2373 
2374 	return (error);
2375 }
2376 
2377 void
2378 ip6_clearpktopts(struct ip6_pktopts *pktopt, int optname)
2379 {
2380 	if (pktopt == NULL)
2381 		return;
2382 
2383 	if (optname == -1 || optname == IPV6_PKTINFO) {
2384 		if (pktopt->ip6po_pktinfo)
2385 			free(pktopt->ip6po_pktinfo, M_IP6OPT);
2386 		pktopt->ip6po_pktinfo = NULL;
2387 	}
2388 	if (optname == -1 || optname == IPV6_HOPLIMIT)
2389 		pktopt->ip6po_hlim = -1;
2390 	if (optname == -1 || optname == IPV6_TCLASS)
2391 		pktopt->ip6po_tclass = -1;
2392 	if (optname == -1 || optname == IPV6_NEXTHOP) {
2393 		if (pktopt->ip6po_nextroute.ro_rt) {
2394 			RTFREE(pktopt->ip6po_nextroute.ro_rt);
2395 			pktopt->ip6po_nextroute.ro_rt = NULL;
2396 		}
2397 		if (pktopt->ip6po_nexthop)
2398 			free(pktopt->ip6po_nexthop, M_IP6OPT);
2399 		pktopt->ip6po_nexthop = NULL;
2400 	}
2401 	if (optname == -1 || optname == IPV6_HOPOPTS) {
2402 		if (pktopt->ip6po_hbh)
2403 			free(pktopt->ip6po_hbh, M_IP6OPT);
2404 		pktopt->ip6po_hbh = NULL;
2405 	}
2406 	if (optname == -1 || optname == IPV6_RTHDRDSTOPTS) {
2407 		if (pktopt->ip6po_dest1)
2408 			free(pktopt->ip6po_dest1, M_IP6OPT);
2409 		pktopt->ip6po_dest1 = NULL;
2410 	}
2411 	if (optname == -1 || optname == IPV6_RTHDR) {
2412 		if (pktopt->ip6po_rhinfo.ip6po_rhi_rthdr)
2413 			free(pktopt->ip6po_rhinfo.ip6po_rhi_rthdr, M_IP6OPT);
2414 		pktopt->ip6po_rhinfo.ip6po_rhi_rthdr = NULL;
2415 		if (pktopt->ip6po_route.ro_rt) {
2416 			RTFREE(pktopt->ip6po_route.ro_rt);
2417 			pktopt->ip6po_route.ro_rt = NULL;
2418 		}
2419 	}
2420 	if (optname == -1 || optname == IPV6_DSTOPTS) {
2421 		if (pktopt->ip6po_dest2)
2422 			free(pktopt->ip6po_dest2, M_IP6OPT);
2423 		pktopt->ip6po_dest2 = NULL;
2424 	}
2425 }
2426 
2427 #define PKTOPT_EXTHDRCPY(type) \
2428 do {\
2429 	if (src->type) {\
2430 		int hlen = (((struct ip6_ext *)src->type)->ip6e_len + 1) << 3;\
2431 		dst->type = malloc(hlen, M_IP6OPT, canwait);\
2432 		if (dst->type == NULL && canwait == M_NOWAIT)\
2433 			goto bad;\
2434 		bcopy(src->type, dst->type, hlen);\
2435 	}\
2436 } while (/*CONSTCOND*/ 0)
2437 
2438 static int
2439 copypktopts(struct ip6_pktopts *dst, struct ip6_pktopts *src, int canwait)
2440 {
2441 	if (dst == NULL || src == NULL)  {
2442 		printf("ip6_clearpktopts: invalid argument\n");
2443 		return (EINVAL);
2444 	}
2445 
2446 	dst->ip6po_hlim = src->ip6po_hlim;
2447 	dst->ip6po_tclass = src->ip6po_tclass;
2448 	dst->ip6po_flags = src->ip6po_flags;
2449 	dst->ip6po_minmtu = src->ip6po_minmtu;
2450 	dst->ip6po_prefer_tempaddr = src->ip6po_prefer_tempaddr;
2451 	if (src->ip6po_pktinfo) {
2452 		dst->ip6po_pktinfo = malloc(sizeof(*dst->ip6po_pktinfo),
2453 		    M_IP6OPT, canwait);
2454 		if (dst->ip6po_pktinfo == NULL)
2455 			goto bad;
2456 		*dst->ip6po_pktinfo = *src->ip6po_pktinfo;
2457 	}
2458 	if (src->ip6po_nexthop) {
2459 		dst->ip6po_nexthop = malloc(src->ip6po_nexthop->sa_len,
2460 		    M_IP6OPT, canwait);
2461 		if (dst->ip6po_nexthop == NULL)
2462 			goto bad;
2463 		bcopy(src->ip6po_nexthop, dst->ip6po_nexthop,
2464 		    src->ip6po_nexthop->sa_len);
2465 	}
2466 	PKTOPT_EXTHDRCPY(ip6po_hbh);
2467 	PKTOPT_EXTHDRCPY(ip6po_dest1);
2468 	PKTOPT_EXTHDRCPY(ip6po_dest2);
2469 	PKTOPT_EXTHDRCPY(ip6po_rthdr); /* not copy the cached route */
2470 	return (0);
2471 
2472   bad:
2473 	ip6_clearpktopts(dst, -1);
2474 	return (ENOBUFS);
2475 }
2476 #undef PKTOPT_EXTHDRCPY
2477 
2478 struct ip6_pktopts *
2479 ip6_copypktopts(struct ip6_pktopts *src, int canwait)
2480 {
2481 	int error;
2482 	struct ip6_pktopts *dst;
2483 
2484 	dst = malloc(sizeof(*dst), M_IP6OPT, canwait);
2485 	if (dst == NULL)
2486 		return (NULL);
2487 	ip6_initpktopts(dst);
2488 
2489 	if ((error = copypktopts(dst, src, canwait)) != 0) {
2490 		free(dst, M_IP6OPT);
2491 		return (NULL);
2492 	}
2493 
2494 	return (dst);
2495 }
2496 
2497 void
2498 ip6_freepcbopts(struct ip6_pktopts *pktopt)
2499 {
2500 	if (pktopt == NULL)
2501 		return;
2502 
2503 	ip6_clearpktopts(pktopt, -1);
2504 
2505 	free(pktopt, M_IP6OPT);
2506 }
2507 
2508 /*
2509  * Set IPv6 outgoing packet options based on advanced API.
2510  */
2511 int
2512 ip6_setpktopts(struct mbuf *control, struct ip6_pktopts *opt,
2513     struct ip6_pktopts *stickyopt, struct ucred *cred, int uproto)
2514 {
2515 	struct cmsghdr *cm = 0;
2516 
2517 	if (control == NULL || opt == NULL)
2518 		return (EINVAL);
2519 
2520 	ip6_initpktopts(opt);
2521 	if (stickyopt) {
2522 		int error;
2523 
2524 		/*
2525 		 * If stickyopt is provided, make a local copy of the options
2526 		 * for this particular packet, then override them by ancillary
2527 		 * objects.
2528 		 * XXX: copypktopts() does not copy the cached route to a next
2529 		 * hop (if any).  This is not very good in terms of efficiency,
2530 		 * but we can allow this since this option should be rarely
2531 		 * used.
2532 		 */
2533 		if ((error = copypktopts(opt, stickyopt, M_NOWAIT)) != 0)
2534 			return (error);
2535 	}
2536 
2537 	/*
2538 	 * XXX: Currently, we assume all the optional information is stored
2539 	 * in a single mbuf.
2540 	 */
2541 	if (control->m_next)
2542 		return (EINVAL);
2543 
2544 	for (; control->m_len > 0; control->m_data += CMSG_ALIGN(cm->cmsg_len),
2545 	    control->m_len -= CMSG_ALIGN(cm->cmsg_len)) {
2546 		int error;
2547 
2548 		if (control->m_len < CMSG_LEN(0))
2549 			return (EINVAL);
2550 
2551 		cm = mtod(control, struct cmsghdr *);
2552 		if (cm->cmsg_len == 0 || cm->cmsg_len > control->m_len)
2553 			return (EINVAL);
2554 		if (cm->cmsg_level != IPPROTO_IPV6)
2555 			continue;
2556 
2557 		error = ip6_setpktopt(cm->cmsg_type, CMSG_DATA(cm),
2558 		    cm->cmsg_len - CMSG_LEN(0), opt, cred, 0, 1, uproto);
2559 		if (error)
2560 			return (error);
2561 	}
2562 
2563 	return (0);
2564 }
2565 
2566 /*
2567  * Set a particular packet option, as a sticky option or an ancillary data
2568  * item.  "len" can be 0 only when it's a sticky option.
2569  * We have 4 cases of combination of "sticky" and "cmsg":
2570  * "sticky=0, cmsg=0": impossible
2571  * "sticky=0, cmsg=1": RFC2292 or RFC3542 ancillary data
2572  * "sticky=1, cmsg=0": RFC3542 socket option
2573  * "sticky=1, cmsg=1": RFC2292 socket option
2574  */
2575 static int
2576 ip6_setpktopt(int optname, u_char *buf, int len, struct ip6_pktopts *opt,
2577     struct ucred *cred, int sticky, int cmsg, int uproto)
2578 {
2579 	int minmtupolicy, preftemp;
2580 	int error;
2581 
2582 	if (!sticky && !cmsg) {
2583 #ifdef DIAGNOSTIC
2584 		printf("ip6_setpktopt: impossible case\n");
2585 #endif
2586 		return (EINVAL);
2587 	}
2588 
2589 	/*
2590 	 * IPV6_2292xxx is for backward compatibility to RFC2292, and should
2591 	 * not be specified in the context of RFC3542.  Conversely,
2592 	 * RFC3542 types should not be specified in the context of RFC2292.
2593 	 */
2594 	if (!cmsg) {
2595 		switch (optname) {
2596 		case IPV6_2292PKTINFO:
2597 		case IPV6_2292HOPLIMIT:
2598 		case IPV6_2292NEXTHOP:
2599 		case IPV6_2292HOPOPTS:
2600 		case IPV6_2292DSTOPTS:
2601 		case IPV6_2292RTHDR:
2602 		case IPV6_2292PKTOPTIONS:
2603 			return (ENOPROTOOPT);
2604 		}
2605 	}
2606 	if (sticky && cmsg) {
2607 		switch (optname) {
2608 		case IPV6_PKTINFO:
2609 		case IPV6_HOPLIMIT:
2610 		case IPV6_NEXTHOP:
2611 		case IPV6_HOPOPTS:
2612 		case IPV6_DSTOPTS:
2613 		case IPV6_RTHDRDSTOPTS:
2614 		case IPV6_RTHDR:
2615 		case IPV6_USE_MIN_MTU:
2616 		case IPV6_DONTFRAG:
2617 		case IPV6_TCLASS:
2618 		case IPV6_PREFER_TEMPADDR: /* XXX: not an RFC3542 option */
2619 			return (ENOPROTOOPT);
2620 		}
2621 	}
2622 
2623 	switch (optname) {
2624 	case IPV6_2292PKTINFO:
2625 	case IPV6_PKTINFO:
2626 	{
2627 		struct ifnet *ifp = NULL;
2628 		struct in6_pktinfo *pktinfo;
2629 
2630 		if (len != sizeof(struct in6_pktinfo))
2631 			return (EINVAL);
2632 
2633 		pktinfo = (struct in6_pktinfo *)buf;
2634 
2635 		/*
2636 		 * An application can clear any sticky IPV6_PKTINFO option by
2637 		 * doing a "regular" setsockopt with ipi6_addr being
2638 		 * in6addr_any and ipi6_ifindex being zero.
2639 		 * [RFC 3542, Section 6]
2640 		 */
2641 		if (optname == IPV6_PKTINFO && opt->ip6po_pktinfo &&
2642 		    pktinfo->ipi6_ifindex == 0 &&
2643 		    IN6_IS_ADDR_UNSPECIFIED(&pktinfo->ipi6_addr)) {
2644 			ip6_clearpktopts(opt, optname);
2645 			break;
2646 		}
2647 
2648 		if (uproto == IPPROTO_TCP && optname == IPV6_PKTINFO &&
2649 		    sticky && !IN6_IS_ADDR_UNSPECIFIED(&pktinfo->ipi6_addr)) {
2650 			return (EINVAL);
2651 		}
2652 
2653 		/* validate the interface index if specified. */
2654 		if (pktinfo->ipi6_ifindex > V_if_index)
2655 			 return (ENXIO);
2656 		if (pktinfo->ipi6_ifindex) {
2657 			ifp = ifnet_byindex(pktinfo->ipi6_ifindex);
2658 			if (ifp == NULL)
2659 				return (ENXIO);
2660 		}
2661 
2662 		/*
2663 		 * We store the address anyway, and let in6_selectsrc()
2664 		 * validate the specified address.  This is because ipi6_addr
2665 		 * may not have enough information about its scope zone, and
2666 		 * we may need additional information (such as outgoing
2667 		 * interface or the scope zone of a destination address) to
2668 		 * disambiguate the scope.
2669 		 * XXX: the delay of the validation may confuse the
2670 		 * application when it is used as a sticky option.
2671 		 */
2672 		if (opt->ip6po_pktinfo == NULL) {
2673 			opt->ip6po_pktinfo = malloc(sizeof(*pktinfo),
2674 			    M_IP6OPT, M_NOWAIT);
2675 			if (opt->ip6po_pktinfo == NULL)
2676 				return (ENOBUFS);
2677 		}
2678 		bcopy(pktinfo, opt->ip6po_pktinfo, sizeof(*pktinfo));
2679 		break;
2680 	}
2681 
2682 	case IPV6_2292HOPLIMIT:
2683 	case IPV6_HOPLIMIT:
2684 	{
2685 		int *hlimp;
2686 
2687 		/*
2688 		 * RFC 3542 deprecated the usage of sticky IPV6_HOPLIMIT
2689 		 * to simplify the ordering among hoplimit options.
2690 		 */
2691 		if (optname == IPV6_HOPLIMIT && sticky)
2692 			return (ENOPROTOOPT);
2693 
2694 		if (len != sizeof(int))
2695 			return (EINVAL);
2696 		hlimp = (int *)buf;
2697 		if (*hlimp < -1 || *hlimp > 255)
2698 			return (EINVAL);
2699 
2700 		opt->ip6po_hlim = *hlimp;
2701 		break;
2702 	}
2703 
2704 	case IPV6_TCLASS:
2705 	{
2706 		int tclass;
2707 
2708 		if (len != sizeof(int))
2709 			return (EINVAL);
2710 		tclass = *(int *)buf;
2711 		if (tclass < -1 || tclass > 255)
2712 			return (EINVAL);
2713 
2714 		opt->ip6po_tclass = tclass;
2715 		break;
2716 	}
2717 
2718 	case IPV6_2292NEXTHOP:
2719 	case IPV6_NEXTHOP:
2720 		if (cred != NULL) {
2721 			error = priv_check_cred(cred,
2722 			    PRIV_NETINET_SETHDROPTS, 0);
2723 			if (error)
2724 				return (error);
2725 		}
2726 
2727 		if (len == 0) {	/* just remove the option */
2728 			ip6_clearpktopts(opt, IPV6_NEXTHOP);
2729 			break;
2730 		}
2731 
2732 		/* check if cmsg_len is large enough for sa_len */
2733 		if (len < sizeof(struct sockaddr) || len < *buf)
2734 			return (EINVAL);
2735 
2736 		switch (((struct sockaddr *)buf)->sa_family) {
2737 		case AF_INET6:
2738 		{
2739 			struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)buf;
2740 			int error;
2741 
2742 			if (sa6->sin6_len != sizeof(struct sockaddr_in6))
2743 				return (EINVAL);
2744 
2745 			if (IN6_IS_ADDR_UNSPECIFIED(&sa6->sin6_addr) ||
2746 			    IN6_IS_ADDR_MULTICAST(&sa6->sin6_addr)) {
2747 				return (EINVAL);
2748 			}
2749 			if ((error = sa6_embedscope(sa6, V_ip6_use_defzone))
2750 			    != 0) {
2751 				return (error);
2752 			}
2753 			break;
2754 		}
2755 		case AF_LINK:	/* should eventually be supported */
2756 		default:
2757 			return (EAFNOSUPPORT);
2758 		}
2759 
2760 		/* turn off the previous option, then set the new option. */
2761 		ip6_clearpktopts(opt, IPV6_NEXTHOP);
2762 		opt->ip6po_nexthop = malloc(*buf, M_IP6OPT, M_NOWAIT);
2763 		if (opt->ip6po_nexthop == NULL)
2764 			return (ENOBUFS);
2765 		bcopy(buf, opt->ip6po_nexthop, *buf);
2766 		break;
2767 
2768 	case IPV6_2292HOPOPTS:
2769 	case IPV6_HOPOPTS:
2770 	{
2771 		struct ip6_hbh *hbh;
2772 		int hbhlen;
2773 
2774 		/*
2775 		 * XXX: We don't allow a non-privileged user to set ANY HbH
2776 		 * options, since per-option restriction has too much
2777 		 * overhead.
2778 		 */
2779 		if (cred != NULL) {
2780 			error = priv_check_cred(cred,
2781 			    PRIV_NETINET_SETHDROPTS, 0);
2782 			if (error)
2783 				return (error);
2784 		}
2785 
2786 		if (len == 0) {
2787 			ip6_clearpktopts(opt, IPV6_HOPOPTS);
2788 			break;	/* just remove the option */
2789 		}
2790 
2791 		/* message length validation */
2792 		if (len < sizeof(struct ip6_hbh))
2793 			return (EINVAL);
2794 		hbh = (struct ip6_hbh *)buf;
2795 		hbhlen = (hbh->ip6h_len + 1) << 3;
2796 		if (len != hbhlen)
2797 			return (EINVAL);
2798 
2799 		/* turn off the previous option, then set the new option. */
2800 		ip6_clearpktopts(opt, IPV6_HOPOPTS);
2801 		opt->ip6po_hbh = malloc(hbhlen, M_IP6OPT, M_NOWAIT);
2802 		if (opt->ip6po_hbh == NULL)
2803 			return (ENOBUFS);
2804 		bcopy(hbh, opt->ip6po_hbh, hbhlen);
2805 
2806 		break;
2807 	}
2808 
2809 	case IPV6_2292DSTOPTS:
2810 	case IPV6_DSTOPTS:
2811 	case IPV6_RTHDRDSTOPTS:
2812 	{
2813 		struct ip6_dest *dest, **newdest = NULL;
2814 		int destlen;
2815 
2816 		if (cred != NULL) { /* XXX: see the comment for IPV6_HOPOPTS */
2817 			error = priv_check_cred(cred,
2818 			    PRIV_NETINET_SETHDROPTS, 0);
2819 			if (error)
2820 				return (error);
2821 		}
2822 
2823 		if (len == 0) {
2824 			ip6_clearpktopts(opt, optname);
2825 			break;	/* just remove the option */
2826 		}
2827 
2828 		/* message length validation */
2829 		if (len < sizeof(struct ip6_dest))
2830 			return (EINVAL);
2831 		dest = (struct ip6_dest *)buf;
2832 		destlen = (dest->ip6d_len + 1) << 3;
2833 		if (len != destlen)
2834 			return (EINVAL);
2835 
2836 		/*
2837 		 * Determine the position that the destination options header
2838 		 * should be inserted; before or after the routing header.
2839 		 */
2840 		switch (optname) {
2841 		case IPV6_2292DSTOPTS:
2842 			/*
2843 			 * The old advacned API is ambiguous on this point.
2844 			 * Our approach is to determine the position based
2845 			 * according to the existence of a routing header.
2846 			 * Note, however, that this depends on the order of the
2847 			 * extension headers in the ancillary data; the 1st
2848 			 * part of the destination options header must appear
2849 			 * before the routing header in the ancillary data,
2850 			 * too.
2851 			 * RFC3542 solved the ambiguity by introducing
2852 			 * separate ancillary data or option types.
2853 			 */
2854 			if (opt->ip6po_rthdr == NULL)
2855 				newdest = &opt->ip6po_dest1;
2856 			else
2857 				newdest = &opt->ip6po_dest2;
2858 			break;
2859 		case IPV6_RTHDRDSTOPTS:
2860 			newdest = &opt->ip6po_dest1;
2861 			break;
2862 		case IPV6_DSTOPTS:
2863 			newdest = &opt->ip6po_dest2;
2864 			break;
2865 		}
2866 
2867 		/* turn off the previous option, then set the new option. */
2868 		ip6_clearpktopts(opt, optname);
2869 		*newdest = malloc(destlen, M_IP6OPT, M_NOWAIT);
2870 		if (*newdest == NULL)
2871 			return (ENOBUFS);
2872 		bcopy(dest, *newdest, destlen);
2873 
2874 		break;
2875 	}
2876 
2877 	case IPV6_2292RTHDR:
2878 	case IPV6_RTHDR:
2879 	{
2880 		struct ip6_rthdr *rth;
2881 		int rthlen;
2882 
2883 		if (len == 0) {
2884 			ip6_clearpktopts(opt, IPV6_RTHDR);
2885 			break;	/* just remove the option */
2886 		}
2887 
2888 		/* message length validation */
2889 		if (len < sizeof(struct ip6_rthdr))
2890 			return (EINVAL);
2891 		rth = (struct ip6_rthdr *)buf;
2892 		rthlen = (rth->ip6r_len + 1) << 3;
2893 		if (len != rthlen)
2894 			return (EINVAL);
2895 
2896 		switch (rth->ip6r_type) {
2897 		case IPV6_RTHDR_TYPE_0:
2898 			if (rth->ip6r_len == 0)	/* must contain one addr */
2899 				return (EINVAL);
2900 			if (rth->ip6r_len % 2) /* length must be even */
2901 				return (EINVAL);
2902 			if (rth->ip6r_len / 2 != rth->ip6r_segleft)
2903 				return (EINVAL);
2904 			break;
2905 		default:
2906 			return (EINVAL);	/* not supported */
2907 		}
2908 
2909 		/* turn off the previous option */
2910 		ip6_clearpktopts(opt, IPV6_RTHDR);
2911 		opt->ip6po_rthdr = malloc(rthlen, M_IP6OPT, M_NOWAIT);
2912 		if (opt->ip6po_rthdr == NULL)
2913 			return (ENOBUFS);
2914 		bcopy(rth, opt->ip6po_rthdr, rthlen);
2915 
2916 		break;
2917 	}
2918 
2919 	case IPV6_USE_MIN_MTU:
2920 		if (len != sizeof(int))
2921 			return (EINVAL);
2922 		minmtupolicy = *(int *)buf;
2923 		if (minmtupolicy != IP6PO_MINMTU_MCASTONLY &&
2924 		    minmtupolicy != IP6PO_MINMTU_DISABLE &&
2925 		    minmtupolicy != IP6PO_MINMTU_ALL) {
2926 			return (EINVAL);
2927 		}
2928 		opt->ip6po_minmtu = minmtupolicy;
2929 		break;
2930 
2931 	case IPV6_DONTFRAG:
2932 		if (len != sizeof(int))
2933 			return (EINVAL);
2934 
2935 		if (uproto == IPPROTO_TCP || *(int *)buf == 0) {
2936 			/*
2937 			 * we ignore this option for TCP sockets.
2938 			 * (RFC3542 leaves this case unspecified.)
2939 			 */
2940 			opt->ip6po_flags &= ~IP6PO_DONTFRAG;
2941 		} else
2942 			opt->ip6po_flags |= IP6PO_DONTFRAG;
2943 		break;
2944 
2945 	case IPV6_PREFER_TEMPADDR:
2946 		if (len != sizeof(int))
2947 			return (EINVAL);
2948 		preftemp = *(int *)buf;
2949 		if (preftemp != IP6PO_TEMPADDR_SYSTEM &&
2950 		    preftemp != IP6PO_TEMPADDR_NOTPREFER &&
2951 		    preftemp != IP6PO_TEMPADDR_PREFER) {
2952 			return (EINVAL);
2953 		}
2954 		opt->ip6po_prefer_tempaddr = preftemp;
2955 		break;
2956 
2957 	default:
2958 		return (ENOPROTOOPT);
2959 	} /* end of switch */
2960 
2961 	return (0);
2962 }
2963 
2964 /*
2965  * Routine called from ip6_output() to loop back a copy of an IP6 multicast
2966  * packet to the input queue of a specified interface.  Note that this
2967  * calls the output routine of the loopback "driver", but with an interface
2968  * pointer that might NOT be &loif -- easier than replicating that code here.
2969  */
2970 void
2971 ip6_mloopback(struct ifnet *ifp, struct mbuf *m, struct sockaddr_in6 *dst)
2972 {
2973 	struct mbuf *copym;
2974 	struct ip6_hdr *ip6;
2975 
2976 	copym = m_copy(m, 0, M_COPYALL);
2977 	if (copym == NULL)
2978 		return;
2979 
2980 	/*
2981 	 * Make sure to deep-copy IPv6 header portion in case the data
2982 	 * is in an mbuf cluster, so that we can safely override the IPv6
2983 	 * header portion later.
2984 	 */
2985 	if ((copym->m_flags & M_EXT) != 0 ||
2986 	    copym->m_len < sizeof(struct ip6_hdr)) {
2987 		copym = m_pullup(copym, sizeof(struct ip6_hdr));
2988 		if (copym == NULL)
2989 			return;
2990 	}
2991 
2992 #ifdef DIAGNOSTIC
2993 	if (copym->m_len < sizeof(*ip6)) {
2994 		m_freem(copym);
2995 		return;
2996 	}
2997 #endif
2998 
2999 	ip6 = mtod(copym, struct ip6_hdr *);
3000 	/*
3001 	 * clear embedded scope identifiers if necessary.
3002 	 * in6_clearscope will touch the addresses only when necessary.
3003 	 */
3004 	in6_clearscope(&ip6->ip6_src);
3005 	in6_clearscope(&ip6->ip6_dst);
3006 
3007 	(void)if_simloop(ifp, copym, dst->sin6_family, 0);
3008 }
3009 
3010 /*
3011  * Chop IPv6 header off from the payload.
3012  */
3013 static int
3014 ip6_splithdr(struct mbuf *m, struct ip6_exthdrs *exthdrs)
3015 {
3016 	struct mbuf *mh;
3017 	struct ip6_hdr *ip6;
3018 
3019 	ip6 = mtod(m, struct ip6_hdr *);
3020 	if (m->m_len > sizeof(*ip6)) {
3021 		mh = m_gethdr(M_NOWAIT, MT_DATA);
3022 		if (mh == NULL) {
3023 			m_freem(m);
3024 			return ENOBUFS;
3025 		}
3026 		m_move_pkthdr(mh, m);
3027 		MH_ALIGN(mh, sizeof(*ip6));
3028 		m->m_len -= sizeof(*ip6);
3029 		m->m_data += sizeof(*ip6);
3030 		mh->m_next = m;
3031 		m = mh;
3032 		m->m_len = sizeof(*ip6);
3033 		bcopy((caddr_t)ip6, mtod(m, caddr_t), sizeof(*ip6));
3034 	}
3035 	exthdrs->ip6e_ip6 = m;
3036 	return 0;
3037 }
3038 
3039 /*
3040  * Compute IPv6 extension header length.
3041  */
3042 int
3043 ip6_optlen(struct inpcb *in6p)
3044 {
3045 	int len;
3046 
3047 	if (!in6p->in6p_outputopts)
3048 		return 0;
3049 
3050 	len = 0;
3051 #define elen(x) \
3052     (((struct ip6_ext *)(x)) ? (((struct ip6_ext *)(x))->ip6e_len + 1) << 3 : 0)
3053 
3054 	len += elen(in6p->in6p_outputopts->ip6po_hbh);
3055 	if (in6p->in6p_outputopts->ip6po_rthdr)
3056 		/* dest1 is valid with rthdr only */
3057 		len += elen(in6p->in6p_outputopts->ip6po_dest1);
3058 	len += elen(in6p->in6p_outputopts->ip6po_rthdr);
3059 	len += elen(in6p->in6p_outputopts->ip6po_dest2);
3060 	return len;
3061 #undef elen
3062 }
3063