xref: /freebsd/sys/netinet6/ip6_output.c (revision 5e53a4f90f82c4345f277dd87cc9292f26e04a29)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the project nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  *	$KAME: ip6_output.c,v 1.279 2002/01/26 06:12:30 jinmei Exp $
32  */
33 
34 /*-
35  * Copyright (c) 1982, 1986, 1988, 1990, 1993
36  *	The Regents of the University of California.  All rights reserved.
37  *
38  * Redistribution and use in source and binary forms, with or without
39  * modification, are permitted provided that the following conditions
40  * are met:
41  * 1. Redistributions of source code must retain the above copyright
42  *    notice, this list of conditions and the following disclaimer.
43  * 2. Redistributions in binary form must reproduce the above copyright
44  *    notice, this list of conditions and the following disclaimer in the
45  *    documentation and/or other materials provided with the distribution.
46  * 3. Neither the name of the University nor the names of its contributors
47  *    may be used to endorse or promote products derived from this software
48  *    without specific prior written permission.
49  *
50  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
51  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
52  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
53  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
54  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
55  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
56  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
57  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
58  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
59  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
60  * SUCH DAMAGE.
61  *
62  *	@(#)ip_output.c	8.3 (Berkeley) 1/21/94
63  */
64 
65 #include <sys/cdefs.h>
66 __FBSDID("$FreeBSD$");
67 
68 #include "opt_inet.h"
69 #include "opt_inet6.h"
70 #include "opt_ratelimit.h"
71 #include "opt_ipsec.h"
72 #include "opt_sctp.h"
73 #include "opt_route.h"
74 #include "opt_rss.h"
75 
76 #include <sys/param.h>
77 #include <sys/kernel.h>
78 #include <sys/malloc.h>
79 #include <sys/mbuf.h>
80 #include <sys/errno.h>
81 #include <sys/priv.h>
82 #include <sys/proc.h>
83 #include <sys/protosw.h>
84 #include <sys/socket.h>
85 #include <sys/socketvar.h>
86 #include <sys/syslog.h>
87 #include <sys/ucred.h>
88 
89 #include <machine/in_cksum.h>
90 
91 #include <net/if.h>
92 #include <net/if_var.h>
93 #include <net/if_llatbl.h>
94 #include <net/netisr.h>
95 #include <net/route.h>
96 #include <net/pfil.h>
97 #include <net/rss_config.h>
98 #include <net/vnet.h>
99 
100 #include <netinet/in.h>
101 #include <netinet/in_var.h>
102 #include <netinet/ip_var.h>
103 #include <netinet6/in6_fib.h>
104 #include <netinet6/in6_var.h>
105 #include <netinet/ip6.h>
106 #include <netinet/icmp6.h>
107 #include <netinet6/ip6_var.h>
108 #include <netinet/in_pcb.h>
109 #include <netinet/tcp_var.h>
110 #include <netinet6/nd6.h>
111 #include <netinet6/in6_rss.h>
112 
113 #include <netipsec/ipsec_support.h>
114 #ifdef SCTP
115 #include <netinet/sctp.h>
116 #include <netinet/sctp_crc32.h>
117 #endif
118 
119 #include <netinet6/ip6protosw.h>
120 #include <netinet6/scope6_var.h>
121 
122 extern int in6_mcast_loop;
123 
124 struct ip6_exthdrs {
125 	struct mbuf *ip6e_ip6;
126 	struct mbuf *ip6e_hbh;
127 	struct mbuf *ip6e_dest1;
128 	struct mbuf *ip6e_rthdr;
129 	struct mbuf *ip6e_dest2;
130 };
131 
132 static MALLOC_DEFINE(M_IP6OPT, "ip6opt", "IPv6 options");
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 *, int,
148 	struct ifnet *, const struct in6_addr *, u_long *, int *, u_int,
149 	u_int);
150 static int ip6_calcmtu(struct ifnet *, const struct in6_addr *, u_long,
151 	u_long *, int *, u_int);
152 static int ip6_getpmtu_ctl(u_int, const struct in6_addr *, u_long *);
153 static int copypktopts(struct ip6_pktopts *, struct ip6_pktopts *, int);
154 
155 
156 /*
157  * Make an extension header from option data.  hp is the source, and
158  * mp is the destination.
159  */
160 #define MAKE_EXTHDR(hp, mp)						\
161     do {								\
162 	if (hp) {							\
163 		struct ip6_ext *eh = (struct ip6_ext *)(hp);		\
164 		error = ip6_copyexthdr((mp), (caddr_t)(hp),		\
165 		    ((eh)->ip6e_len + 1) << 3);				\
166 		if (error)						\
167 			goto freehdrs;					\
168 	}								\
169     } while (/*CONSTCOND*/ 0)
170 
171 /*
172  * Form a chain of extension headers.
173  * m is the extension header mbuf
174  * mp is the previous mbuf in the chain
175  * p is the next header
176  * i is the type of option.
177  */
178 #define MAKE_CHAIN(m, mp, p, i)\
179     do {\
180 	if (m) {\
181 		if (!hdrsplit) \
182 			panic("assumption failed: hdr not split"); \
183 		*mtod((m), u_char *) = *(p);\
184 		*(p) = (i);\
185 		p = mtod((m), u_char *);\
186 		(m)->m_next = (mp)->m_next;\
187 		(mp)->m_next = (m);\
188 		(mp) = (m);\
189 	}\
190     } while (/*CONSTCOND*/ 0)
191 
192 void
193 in6_delayed_cksum(struct mbuf *m, uint32_t plen, u_short offset)
194 {
195 	u_short csum;
196 
197 	csum = in_cksum_skip(m, offset + plen, offset);
198 	if (m->m_pkthdr.csum_flags & CSUM_UDP_IPV6 && csum == 0)
199 		csum = 0xffff;
200 	offset += m->m_pkthdr.csum_data;	/* checksum offset */
201 
202 	if (offset + sizeof(u_short) > m->m_len) {
203 		printf("%s: delayed m_pullup, m->len: %d plen %u off %u "
204 		    "csum_flags=%b\n", __func__, m->m_len, plen, offset,
205 		    (int)m->m_pkthdr.csum_flags, CSUM_BITS);
206 		/*
207 		 * XXX this should not happen, but if it does, the correct
208 		 * behavior may be to insert the checksum in the appropriate
209 		 * next mbuf in the chain.
210 		 */
211 		return;
212 	}
213 	*(u_short *)(m->m_data + offset) = csum;
214 }
215 
216 int
217 ip6_fragment(struct ifnet *ifp, struct mbuf *m0, int hlen, u_char nextproto,
218     int fraglen , uint32_t id)
219 {
220 	struct mbuf *m, **mnext, *m_frgpart;
221 	struct ip6_hdr *ip6, *mhip6;
222 	struct ip6_frag *ip6f;
223 	int off;
224 	int error;
225 	int tlen = m0->m_pkthdr.len;
226 
227 	KASSERT((fraglen % 8 == 0), ("Fragment length must be a multiple of 8"));
228 
229 	m = m0;
230 	ip6 = mtod(m, struct ip6_hdr *);
231 	mnext = &m->m_nextpkt;
232 
233 	for (off = hlen; off < tlen; off += fraglen) {
234 		m = m_gethdr(M_NOWAIT, MT_DATA);
235 		if (!m) {
236 			IP6STAT_INC(ip6s_odropped);
237 			return (ENOBUFS);
238 		}
239 		m->m_flags = m0->m_flags & M_COPYFLAGS;
240 		*mnext = m;
241 		mnext = &m->m_nextpkt;
242 		m->m_data += max_linkhdr;
243 		mhip6 = mtod(m, struct ip6_hdr *);
244 		*mhip6 = *ip6;
245 		m->m_len = sizeof(*mhip6);
246 		error = ip6_insertfraghdr(m0, m, hlen, &ip6f);
247 		if (error) {
248 			IP6STAT_INC(ip6s_odropped);
249 			return (error);
250 		}
251 		ip6f->ip6f_offlg = htons((u_short)((off - hlen) & ~7));
252 		if (off + fraglen >= tlen)
253 			fraglen = tlen - off;
254 		else
255 			ip6f->ip6f_offlg |= IP6F_MORE_FRAG;
256 		mhip6->ip6_plen = htons((u_short)(fraglen + hlen +
257 		    sizeof(*ip6f) - sizeof(struct ip6_hdr)));
258 		if ((m_frgpart = m_copym(m0, off, fraglen, M_NOWAIT)) == NULL) {
259 			IP6STAT_INC(ip6s_odropped);
260 			return (ENOBUFS);
261 		}
262 		m_cat(m, m_frgpart);
263 		m->m_pkthdr.len = fraglen + hlen + sizeof(*ip6f);
264 		m->m_pkthdr.fibnum = m0->m_pkthdr.fibnum;
265 		m->m_pkthdr.rcvif = NULL;
266 		ip6f->ip6f_reserved = 0;
267 		ip6f->ip6f_ident = id;
268 		ip6f->ip6f_nxt = nextproto;
269 		IP6STAT_INC(ip6s_ofragments);
270 		in6_ifstat_inc(ifp, ifs6_out_fragcreat);
271 	}
272 
273 	return (0);
274 }
275 
276 /*
277  * IP6 output. The packet in mbuf chain m contains a skeletal IP6
278  * header (with pri, len, nxt, hlim, src, dst).
279  * This function may modify ver and hlim only.
280  * The mbuf chain containing the packet will be freed.
281  * The mbuf opt, if present, will not be freed.
282  * If route_in6 ro is present and has ro_rt initialized, route lookup would be
283  * skipped and ro->ro_rt would be used. If ro is present but ro->ro_rt is NULL,
284  * then result of route lookup is stored in ro->ro_rt.
285  *
286  * type of "mtu": rt_mtu is u_long, ifnet.ifr_mtu is int, and
287  * nd_ifinfo.linkmtu is u_int32_t.  so we use u_long to hold largest one,
288  * which is rt_mtu.
289  *
290  * ifpp - XXX: just for statistics
291  */
292 /*
293  * XXX TODO: no flowid is assigned for outbound flows?
294  */
295 int
296 ip6_output(struct mbuf *m0, struct ip6_pktopts *opt,
297     struct route_in6 *ro, int flags, struct ip6_moptions *im6o,
298     struct ifnet **ifpp, struct inpcb *inp)
299 {
300 	struct ip6_hdr *ip6;
301 	struct ifnet *ifp, *origifp;
302 	struct mbuf *m = m0;
303 	struct mbuf *mprev = NULL;
304 	int hlen, tlen, len;
305 	struct route_in6 ip6route;
306 	struct rtentry *rt = NULL;
307 	struct sockaddr_in6 *dst, src_sa, dst_sa;
308 	struct in6_addr odst;
309 	int error = 0;
310 	struct in6_ifaddr *ia = NULL;
311 	u_long mtu;
312 	int alwaysfrag, dontfrag;
313 	u_int32_t optlen = 0, plen = 0, unfragpartlen = 0;
314 	struct ip6_exthdrs exthdrs;
315 	struct in6_addr src0, dst0;
316 	u_int32_t zone;
317 	struct route_in6 *ro_pmtu = NULL;
318 	int hdrsplit = 0;
319 	int sw_csum, tso;
320 	int needfiblookup;
321 	uint32_t fibnum;
322 	struct m_tag *fwd_tag = NULL;
323 	uint32_t id;
324 
325 	if (inp != NULL) {
326 		INP_LOCK_ASSERT(inp);
327 		M_SETFIB(m, inp->inp_inc.inc_fibnum);
328 		if ((flags & IP_NODEFAULTFLOWID) == 0) {
329 			/* unconditionally set flowid */
330 			m->m_pkthdr.flowid = inp->inp_flowid;
331 			M_HASHTYPE_SET(m, inp->inp_flowtype);
332 		}
333 	}
334 
335 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
336 	/*
337 	 * IPSec checking which handles several cases.
338 	 * FAST IPSEC: We re-injected the packet.
339 	 * XXX: need scope argument.
340 	 */
341 	if (IPSEC_ENABLED(ipv6)) {
342 		if ((error = IPSEC_OUTPUT(ipv6, m, inp)) != 0) {
343 			if (error == EINPROGRESS)
344 				error = 0;
345 			goto done;
346 		}
347 	}
348 #endif /* IPSEC */
349 
350 	bzero(&exthdrs, sizeof(exthdrs));
351 	if (opt) {
352 		/* Hop-by-Hop options header */
353 		MAKE_EXTHDR(opt->ip6po_hbh, &exthdrs.ip6e_hbh);
354 		/* Destination options header(1st part) */
355 		if (opt->ip6po_rthdr) {
356 			/*
357 			 * Destination options header(1st part)
358 			 * This only makes sense with a routing header.
359 			 * See Section 9.2 of RFC 3542.
360 			 * Disabling this part just for MIP6 convenience is
361 			 * a bad idea.  We need to think carefully about a
362 			 * way to make the advanced API coexist with MIP6
363 			 * options, which might automatically be inserted in
364 			 * the kernel.
365 			 */
366 			MAKE_EXTHDR(opt->ip6po_dest1, &exthdrs.ip6e_dest1);
367 		}
368 		/* Routing header */
369 		MAKE_EXTHDR(opt->ip6po_rthdr, &exthdrs.ip6e_rthdr);
370 		/* Destination options header(2nd part) */
371 		MAKE_EXTHDR(opt->ip6po_dest2, &exthdrs.ip6e_dest2);
372 	}
373 
374 	/*
375 	 * Calculate the total length of the extension header chain.
376 	 * Keep the length of the unfragmentable part for fragmentation.
377 	 */
378 	optlen = 0;
379 	if (exthdrs.ip6e_hbh)
380 		optlen += exthdrs.ip6e_hbh->m_len;
381 	if (exthdrs.ip6e_dest1)
382 		optlen += exthdrs.ip6e_dest1->m_len;
383 	if (exthdrs.ip6e_rthdr)
384 		optlen += exthdrs.ip6e_rthdr->m_len;
385 	unfragpartlen = optlen + sizeof(struct ip6_hdr);
386 
387 	/* NOTE: we don't add AH/ESP length here (done in ip6_ipsec_output) */
388 	if (exthdrs.ip6e_dest2)
389 		optlen += exthdrs.ip6e_dest2->m_len;
390 
391 	/*
392 	 * If there is at least one extension header,
393 	 * separate IP6 header from the payload.
394 	 */
395 	if (optlen && !hdrsplit) {
396 		if ((error = ip6_splithdr(m, &exthdrs)) != 0) {
397 			m = NULL;
398 			goto freehdrs;
399 		}
400 		m = exthdrs.ip6e_ip6;
401 		hdrsplit++;
402 	}
403 
404 	ip6 = mtod(m, struct ip6_hdr *);
405 
406 	/* adjust mbuf packet header length */
407 	m->m_pkthdr.len += optlen;
408 	plen = m->m_pkthdr.len - sizeof(*ip6);
409 
410 	/* If this is a jumbo payload, insert a jumbo payload option. */
411 	if (plen > IPV6_MAXPACKET) {
412 		if (!hdrsplit) {
413 			if ((error = ip6_splithdr(m, &exthdrs)) != 0) {
414 				m = NULL;
415 				goto freehdrs;
416 			}
417 			m = exthdrs.ip6e_ip6;
418 			hdrsplit++;
419 		}
420 		/* adjust pointer */
421 		ip6 = mtod(m, struct ip6_hdr *);
422 		if ((error = ip6_insert_jumboopt(&exthdrs, plen)) != 0)
423 			goto freehdrs;
424 		ip6->ip6_plen = 0;
425 	} else
426 		ip6->ip6_plen = htons(plen);
427 
428 	/*
429 	 * Concatenate headers and fill in next header fields.
430 	 * Here we have, on "m"
431 	 *	IPv6 payload
432 	 * and we insert headers accordingly.  Finally, we should be getting:
433 	 *	IPv6 hbh dest1 rthdr ah* [esp* dest2 payload]
434 	 *
435 	 * during the header composing process, "m" points to IPv6 header.
436 	 * "mprev" points to an extension header prior to esp.
437 	 */
438 	u_char *nexthdrp = &ip6->ip6_nxt;
439 	mprev = m;
440 
441 	/*
442 	 * we treat dest2 specially.  this makes IPsec processing
443 	 * much easier.  the goal here is to make mprev point the
444 	 * mbuf prior to dest2.
445 	 *
446 	 * result: IPv6 dest2 payload
447 	 * m and mprev will point to IPv6 header.
448 	 */
449 	if (exthdrs.ip6e_dest2) {
450 		if (!hdrsplit)
451 			panic("assumption failed: hdr not split");
452 		exthdrs.ip6e_dest2->m_next = m->m_next;
453 		m->m_next = exthdrs.ip6e_dest2;
454 		*mtod(exthdrs.ip6e_dest2, u_char *) = ip6->ip6_nxt;
455 		ip6->ip6_nxt = IPPROTO_DSTOPTS;
456 	}
457 
458 	/*
459 	 * result: IPv6 hbh dest1 rthdr dest2 payload
460 	 * m will point to IPv6 header.  mprev will point to the
461 	 * extension header prior to dest2 (rthdr in the above case).
462 	 */
463 	MAKE_CHAIN(exthdrs.ip6e_hbh, mprev, nexthdrp, IPPROTO_HOPOPTS);
464 	MAKE_CHAIN(exthdrs.ip6e_dest1, mprev, nexthdrp,
465 		   IPPROTO_DSTOPTS);
466 	MAKE_CHAIN(exthdrs.ip6e_rthdr, mprev, nexthdrp,
467 		   IPPROTO_ROUTING);
468 
469 	/*
470 	 * If there is a routing header, discard the packet.
471 	 */
472 	if (exthdrs.ip6e_rthdr) {
473 		 error = EINVAL;
474 		 goto bad;
475 	}
476 
477 	/* Source address validation */
478 	if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) &&
479 	    (flags & IPV6_UNSPECSRC) == 0) {
480 		error = EOPNOTSUPP;
481 		IP6STAT_INC(ip6s_badscope);
482 		goto bad;
483 	}
484 	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_src)) {
485 		error = EOPNOTSUPP;
486 		IP6STAT_INC(ip6s_badscope);
487 		goto bad;
488 	}
489 
490 	IP6STAT_INC(ip6s_localout);
491 
492 	/*
493 	 * Route packet.
494 	 */
495 	if (ro == NULL) {
496 		ro = &ip6route;
497 		bzero((caddr_t)ro, sizeof(*ro));
498 	}
499 	ro_pmtu = ro;
500 	if (opt && opt->ip6po_rthdr)
501 		ro = &opt->ip6po_route;
502 	dst = (struct sockaddr_in6 *)&ro->ro_dst;
503 	fibnum = (inp != NULL) ? inp->inp_inc.inc_fibnum : M_GETFIB(m);
504 again:
505 	/*
506 	 * if specified, try to fill in the traffic class field.
507 	 * do not override if a non-zero value is already set.
508 	 * we check the diffserv field and the ecn field separately.
509 	 */
510 	if (opt && opt->ip6po_tclass >= 0) {
511 		int mask = 0;
512 
513 		if ((ip6->ip6_flow & htonl(0xfc << 20)) == 0)
514 			mask |= 0xfc;
515 		if ((ip6->ip6_flow & htonl(0x03 << 20)) == 0)
516 			mask |= 0x03;
517 		if (mask != 0)
518 			ip6->ip6_flow |= htonl((opt->ip6po_tclass & mask) << 20);
519 	}
520 
521 	/* fill in or override the hop limit field, if necessary. */
522 	if (opt && opt->ip6po_hlim != -1)
523 		ip6->ip6_hlim = opt->ip6po_hlim & 0xff;
524 	else if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
525 		if (im6o != NULL)
526 			ip6->ip6_hlim = im6o->im6o_multicast_hlim;
527 		else
528 			ip6->ip6_hlim = V_ip6_defmcasthlim;
529 	}
530 	/*
531 	 * Validate route against routing table additions;
532 	 * a better/more specific route might have been added.
533 	 * Make sure address family is set in route.
534 	 */
535 	if (inp) {
536 		ro->ro_dst.sin6_family = AF_INET6;
537 		RT_VALIDATE((struct route *)ro, &inp->inp_rt_cookie, fibnum);
538 	}
539 	if (ro->ro_rt && fwd_tag == NULL && (ro->ro_rt->rt_flags & RTF_UP) &&
540 	    ro->ro_dst.sin6_family == AF_INET6 &&
541 	    IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, &ip6->ip6_dst)) {
542 		rt = ro->ro_rt;
543 		ifp = ro->ro_rt->rt_ifp;
544 	} else {
545 		if (ro->ro_lle)
546 			LLE_FREE(ro->ro_lle);	/* zeros ro_lle */
547 		ro->ro_lle = NULL;
548 		if (fwd_tag == NULL) {
549 			bzero(&dst_sa, sizeof(dst_sa));
550 			dst_sa.sin6_family = AF_INET6;
551 			dst_sa.sin6_len = sizeof(dst_sa);
552 			dst_sa.sin6_addr = ip6->ip6_dst;
553 		}
554 		error = in6_selectroute_fib(&dst_sa, opt, im6o, ro, &ifp,
555 		    &rt, fibnum);
556 		if (error != 0) {
557 			if (ifp != NULL)
558 				in6_ifstat_inc(ifp, ifs6_out_discard);
559 			goto bad;
560 		}
561 	}
562 	if (rt == NULL) {
563 		/*
564 		 * If in6_selectroute() does not return a route entry,
565 		 * dst may not have been updated.
566 		 */
567 		*dst = dst_sa;	/* XXX */
568 	}
569 
570 	/*
571 	 * then rt (for unicast) and ifp must be non-NULL valid values.
572 	 */
573 	if ((flags & IPV6_FORWARDING) == 0) {
574 		/* XXX: the FORWARDING flag can be set for mrouting. */
575 		in6_ifstat_inc(ifp, ifs6_out_request);
576 	}
577 	if (rt != NULL) {
578 		ia = (struct in6_ifaddr *)(rt->rt_ifa);
579 		counter_u64_add(rt->rt_pksent, 1);
580 	}
581 
582 
583 	/*
584 	 * The outgoing interface must be in the zone of source and
585 	 * destination addresses.
586 	 */
587 	origifp = ifp;
588 
589 	src0 = ip6->ip6_src;
590 	if (in6_setscope(&src0, origifp, &zone))
591 		goto badscope;
592 	bzero(&src_sa, sizeof(src_sa));
593 	src_sa.sin6_family = AF_INET6;
594 	src_sa.sin6_len = sizeof(src_sa);
595 	src_sa.sin6_addr = ip6->ip6_src;
596 	if (sa6_recoverscope(&src_sa) || zone != src_sa.sin6_scope_id)
597 		goto badscope;
598 
599 	dst0 = ip6->ip6_dst;
600 	if (in6_setscope(&dst0, origifp, &zone))
601 		goto badscope;
602 	/* re-initialize to be sure */
603 	bzero(&dst_sa, sizeof(dst_sa));
604 	dst_sa.sin6_family = AF_INET6;
605 	dst_sa.sin6_len = sizeof(dst_sa);
606 	dst_sa.sin6_addr = ip6->ip6_dst;
607 	if (sa6_recoverscope(&dst_sa) || zone != dst_sa.sin6_scope_id) {
608 		goto badscope;
609 	}
610 
611 	/* We should use ia_ifp to support the case of
612 	 * sending packets to an address of our own.
613 	 */
614 	if (ia != NULL && ia->ia_ifp)
615 		ifp = ia->ia_ifp;
616 
617 	/* scope check is done. */
618 	goto routefound;
619 
620   badscope:
621 	IP6STAT_INC(ip6s_badscope);
622 	in6_ifstat_inc(origifp, ifs6_out_discard);
623 	if (error == 0)
624 		error = EHOSTUNREACH; /* XXX */
625 	goto bad;
626 
627   routefound:
628 	if (rt && !IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
629 		if (opt && opt->ip6po_nextroute.ro_rt) {
630 			/*
631 			 * The nexthop is explicitly specified by the
632 			 * application.  We assume the next hop is an IPv6
633 			 * address.
634 			 */
635 			dst = (struct sockaddr_in6 *)opt->ip6po_nexthop;
636 		}
637 		else if ((rt->rt_flags & RTF_GATEWAY))
638 			dst = (struct sockaddr_in6 *)rt->rt_gateway;
639 	}
640 
641 	if (!IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
642 		m->m_flags &= ~(M_BCAST | M_MCAST); /* just in case */
643 	} else {
644 		m->m_flags = (m->m_flags & ~M_BCAST) | M_MCAST;
645 		in6_ifstat_inc(ifp, ifs6_out_mcast);
646 		/*
647 		 * Confirm that the outgoing interface supports multicast.
648 		 */
649 		if (!(ifp->if_flags & IFF_MULTICAST)) {
650 			IP6STAT_INC(ip6s_noroute);
651 			in6_ifstat_inc(ifp, ifs6_out_discard);
652 			error = ENETUNREACH;
653 			goto bad;
654 		}
655 		if ((im6o == NULL && in6_mcast_loop) ||
656 		    (im6o && im6o->im6o_multicast_loop)) {
657 			/*
658 			 * Loop back multicast datagram if not expressly
659 			 * forbidden to do so, even if we have not joined
660 			 * the address; protocols will filter it later,
661 			 * thus deferring a hash lookup and lock acquisition
662 			 * at the expense of an m_copym().
663 			 */
664 			ip6_mloopback(ifp, m);
665 		} else {
666 			/*
667 			 * If we are acting as a multicast router, perform
668 			 * multicast forwarding as if the packet had just
669 			 * arrived on the interface to which we are about
670 			 * to send.  The multicast forwarding function
671 			 * recursively calls this function, using the
672 			 * IPV6_FORWARDING flag to prevent infinite recursion.
673 			 *
674 			 * Multicasts that are looped back by ip6_mloopback(),
675 			 * above, will be forwarded by the ip6_input() routine,
676 			 * if necessary.
677 			 */
678 			if (V_ip6_mrouter && (flags & IPV6_FORWARDING) == 0) {
679 				/*
680 				 * XXX: ip6_mforward expects that rcvif is NULL
681 				 * when it is called from the originating path.
682 				 * However, it may not always be the case.
683 				 */
684 				m->m_pkthdr.rcvif = NULL;
685 				if (ip6_mforward(ip6, ifp, m) != 0) {
686 					m_freem(m);
687 					goto done;
688 				}
689 			}
690 		}
691 		/*
692 		 * Multicasts with a hoplimit of zero may be looped back,
693 		 * above, but must not be transmitted on a network.
694 		 * Also, multicasts addressed to the loopback interface
695 		 * are not sent -- the above call to ip6_mloopback() will
696 		 * loop back a copy if this host actually belongs to the
697 		 * destination group on the loopback interface.
698 		 */
699 		if (ip6->ip6_hlim == 0 || (ifp->if_flags & IFF_LOOPBACK) ||
700 		    IN6_IS_ADDR_MC_INTFACELOCAL(&ip6->ip6_dst)) {
701 			m_freem(m);
702 			goto done;
703 		}
704 	}
705 
706 	/*
707 	 * Fill the outgoing inteface to tell the upper layer
708 	 * to increment per-interface statistics.
709 	 */
710 	if (ifpp)
711 		*ifpp = ifp;
712 
713 	/* Determine path MTU. */
714 	if ((error = ip6_getpmtu(ro_pmtu, ro != ro_pmtu, ifp, &ip6->ip6_dst,
715 		    &mtu, &alwaysfrag, fibnum, *nexthdrp)) != 0)
716 		goto bad;
717 
718 	/*
719 	 * The caller of this function may specify to use the minimum MTU
720 	 * in some cases.
721 	 * An advanced API option (IPV6_USE_MIN_MTU) can also override MTU
722 	 * setting.  The logic is a bit complicated; by default, unicast
723 	 * packets will follow path MTU while multicast packets will be sent at
724 	 * the minimum MTU.  If IP6PO_MINMTU_ALL is specified, all packets
725 	 * including unicast ones will be sent at the minimum MTU.  Multicast
726 	 * packets will always be sent at the minimum MTU unless
727 	 * IP6PO_MINMTU_DISABLE is explicitly specified.
728 	 * See RFC 3542 for more details.
729 	 */
730 	if (mtu > IPV6_MMTU) {
731 		if ((flags & IPV6_MINMTU))
732 			mtu = IPV6_MMTU;
733 		else if (opt && opt->ip6po_minmtu == IP6PO_MINMTU_ALL)
734 			mtu = IPV6_MMTU;
735 		else if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) &&
736 			 (opt == NULL ||
737 			  opt->ip6po_minmtu != IP6PO_MINMTU_DISABLE)) {
738 			mtu = IPV6_MMTU;
739 		}
740 	}
741 
742 	/*
743 	 * clear embedded scope identifiers if necessary.
744 	 * in6_clearscope will touch the addresses only when necessary.
745 	 */
746 	in6_clearscope(&ip6->ip6_src);
747 	in6_clearscope(&ip6->ip6_dst);
748 
749 	/*
750 	 * If the outgoing packet contains a hop-by-hop options header,
751 	 * it must be examined and processed even by the source node.
752 	 * (RFC 2460, section 4.)
753 	 */
754 	if (exthdrs.ip6e_hbh) {
755 		struct ip6_hbh *hbh = mtod(exthdrs.ip6e_hbh, struct ip6_hbh *);
756 		u_int32_t dummy; /* XXX unused */
757 		u_int32_t plen = 0; /* XXX: ip6_process will check the value */
758 
759 #ifdef DIAGNOSTIC
760 		if ((hbh->ip6h_len + 1) << 3 > exthdrs.ip6e_hbh->m_len)
761 			panic("ip6e_hbh is not contiguous");
762 #endif
763 		/*
764 		 *  XXX: if we have to send an ICMPv6 error to the sender,
765 		 *       we need the M_LOOP flag since icmp6_error() expects
766 		 *       the IPv6 and the hop-by-hop options header are
767 		 *       contiguous unless the flag is set.
768 		 */
769 		m->m_flags |= M_LOOP;
770 		m->m_pkthdr.rcvif = ifp;
771 		if (ip6_process_hopopts(m, (u_int8_t *)(hbh + 1),
772 		    ((hbh->ip6h_len + 1) << 3) - sizeof(struct ip6_hbh),
773 		    &dummy, &plen) < 0) {
774 			/* m was already freed at this point */
775 			error = EINVAL;/* better error? */
776 			goto done;
777 		}
778 		m->m_flags &= ~M_LOOP; /* XXX */
779 		m->m_pkthdr.rcvif = NULL;
780 	}
781 
782 	/* Jump over all PFIL processing if hooks are not active. */
783 	if (!PFIL_HOOKED(&V_inet6_pfil_hook))
784 		goto passout;
785 
786 	odst = ip6->ip6_dst;
787 	/* Run through list of hooks for output packets. */
788 	error = pfil_run_hooks(&V_inet6_pfil_hook, &m, ifp, PFIL_OUT, inp);
789 	if (error != 0 || m == NULL)
790 		goto done;
791 	/* adjust pointer */
792 	ip6 = mtod(m, struct ip6_hdr *);
793 
794 	needfiblookup = 0;
795 	/* See if destination IP address was changed by packet filter. */
796 	if (!IN6_ARE_ADDR_EQUAL(&odst, &ip6->ip6_dst)) {
797 		m->m_flags |= M_SKIP_FIREWALL;
798 		/* If destination is now ourself drop to ip6_input(). */
799 		if (in6_localip(&ip6->ip6_dst)) {
800 			m->m_flags |= M_FASTFWD_OURS;
801 			if (m->m_pkthdr.rcvif == NULL)
802 				m->m_pkthdr.rcvif = V_loif;
803 			if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
804 				m->m_pkthdr.csum_flags |=
805 				    CSUM_DATA_VALID_IPV6 | CSUM_PSEUDO_HDR;
806 				m->m_pkthdr.csum_data = 0xffff;
807 			}
808 #ifdef SCTP
809 			if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6)
810 				m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
811 #endif
812 			error = netisr_queue(NETISR_IPV6, m);
813 			goto done;
814 		} else {
815 			RO_RTFREE(ro);
816 			needfiblookup = 1; /* Redo the routing table lookup. */
817 			if (ro->ro_lle)
818 				LLE_FREE(ro->ro_lle);	/* zeros ro_lle */
819 			ro->ro_lle = NULL;
820 		}
821 	}
822 	/* See if fib was changed by packet filter. */
823 	if (fibnum != M_GETFIB(m)) {
824 		m->m_flags |= M_SKIP_FIREWALL;
825 		fibnum = M_GETFIB(m);
826 		RO_RTFREE(ro);
827 		needfiblookup = 1;
828 		if (ro->ro_lle)
829 			LLE_FREE(ro->ro_lle);	/* zeros ro_lle */
830 		ro->ro_lle = NULL;
831 	}
832 	if (needfiblookup)
833 		goto again;
834 
835 	/* See if local, if yes, send it to netisr. */
836 	if (m->m_flags & M_FASTFWD_OURS) {
837 		if (m->m_pkthdr.rcvif == NULL)
838 			m->m_pkthdr.rcvif = V_loif;
839 		if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
840 			m->m_pkthdr.csum_flags |=
841 			    CSUM_DATA_VALID_IPV6 | CSUM_PSEUDO_HDR;
842 			m->m_pkthdr.csum_data = 0xffff;
843 		}
844 #ifdef SCTP
845 		if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6)
846 			m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
847 #endif
848 		error = netisr_queue(NETISR_IPV6, m);
849 		goto done;
850 	}
851 	/* Or forward to some other address? */
852 	if ((m->m_flags & M_IP6_NEXTHOP) &&
853 	    (fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL)) != NULL) {
854 		dst = (struct sockaddr_in6 *)&ro->ro_dst;
855 		bcopy((fwd_tag+1), &dst_sa, sizeof(struct sockaddr_in6));
856 		m->m_flags |= M_SKIP_FIREWALL;
857 		m->m_flags &= ~M_IP6_NEXTHOP;
858 		m_tag_delete(m, fwd_tag);
859 		goto again;
860 	}
861 
862 passout:
863 	/*
864 	 * Send the packet to the outgoing interface.
865 	 * If necessary, do IPv6 fragmentation before sending.
866 	 *
867 	 * the logic here is rather complex:
868 	 * 1: normal case (dontfrag == 0, alwaysfrag == 0)
869 	 * 1-a:	send as is if tlen <= path mtu
870 	 * 1-b:	fragment if tlen > path mtu
871 	 *
872 	 * 2: if user asks us not to fragment (dontfrag == 1)
873 	 * 2-a:	send as is if tlen <= interface mtu
874 	 * 2-b:	error if tlen > interface mtu
875 	 *
876 	 * 3: if we always need to attach fragment header (alwaysfrag == 1)
877 	 *	always fragment
878 	 *
879 	 * 4: if dontfrag == 1 && alwaysfrag == 1
880 	 *	error, as we cannot handle this conflicting request
881 	 */
882 	sw_csum = m->m_pkthdr.csum_flags;
883 	if (!hdrsplit) {
884 		tso = ((sw_csum & ifp->if_hwassist & CSUM_TSO) != 0) ? 1 : 0;
885 		sw_csum &= ~ifp->if_hwassist;
886 	} else
887 		tso = 0;
888 	/*
889 	 * If we added extension headers, we will not do TSO and calculate the
890 	 * checksums ourselves for now.
891 	 * XXX-BZ  Need a framework to know when the NIC can handle it, even
892 	 * with ext. hdrs.
893 	 */
894 	if (sw_csum & CSUM_DELAY_DATA_IPV6) {
895 		sw_csum &= ~CSUM_DELAY_DATA_IPV6;
896 		in6_delayed_cksum(m, plen, sizeof(struct ip6_hdr));
897 	}
898 #ifdef SCTP
899 	if (sw_csum & CSUM_SCTP_IPV6) {
900 		sw_csum &= ~CSUM_SCTP_IPV6;
901 		sctp_delayed_cksum(m, sizeof(struct ip6_hdr));
902 	}
903 #endif
904 	m->m_pkthdr.csum_flags &= ifp->if_hwassist;
905 	tlen = m->m_pkthdr.len;
906 
907 	if ((opt && (opt->ip6po_flags & IP6PO_DONTFRAG)) || tso)
908 		dontfrag = 1;
909 	else
910 		dontfrag = 0;
911 	if (dontfrag && alwaysfrag) {	/* case 4 */
912 		/* conflicting request - can't transmit */
913 		error = EMSGSIZE;
914 		goto bad;
915 	}
916 	if (dontfrag && tlen > IN6_LINKMTU(ifp) && !tso) {	/* case 2-b */
917 		/*
918 		 * Even if the DONTFRAG option is specified, we cannot send the
919 		 * packet when the data length is larger than the MTU of the
920 		 * outgoing interface.
921 		 * Notify the error by sending IPV6_PATHMTU ancillary data if
922 		 * application wanted to know the MTU value. Also return an
923 		 * error code (this is not described in the API spec).
924 		 */
925 		if (inp != NULL)
926 			ip6_notify_pmtu(inp, &dst_sa, (u_int32_t)mtu);
927 		error = EMSGSIZE;
928 		goto bad;
929 	}
930 
931 	/*
932 	 * transmit packet without fragmentation
933 	 */
934 	if (dontfrag || (!alwaysfrag && tlen <= mtu)) {	/* case 1-a and 2-a */
935 		struct in6_ifaddr *ia6;
936 
937 		ip6 = mtod(m, struct ip6_hdr *);
938 		ia6 = in6_ifawithifp(ifp, &ip6->ip6_src);
939 		if (ia6) {
940 			/* Record statistics for this interface address. */
941 			counter_u64_add(ia6->ia_ifa.ifa_opackets, 1);
942 			counter_u64_add(ia6->ia_ifa.ifa_obytes,
943 			    m->m_pkthdr.len);
944 			ifa_free(&ia6->ia_ifa);
945 		}
946 #ifdef RATELIMIT
947 		if (inp != NULL) {
948 			if (inp->inp_flags2 & INP_RATE_LIMIT_CHANGED)
949 				in_pcboutput_txrtlmt(inp, ifp, m);
950 			/* stamp send tag on mbuf */
951 			m->m_pkthdr.snd_tag = inp->inp_snd_tag;
952 		} else {
953 			m->m_pkthdr.snd_tag = NULL;
954 		}
955 #endif
956 		error = nd6_output_ifp(ifp, origifp, m, dst,
957 		    (struct route *)ro);
958 #ifdef RATELIMIT
959 		/* check for route change */
960 		if (error == EAGAIN)
961 			in_pcboutput_eagain(inp);
962 #endif
963 		goto done;
964 	}
965 
966 	/*
967 	 * try to fragment the packet.  case 1-b and 3
968 	 */
969 	if (mtu < IPV6_MMTU) {
970 		/* path MTU cannot be less than IPV6_MMTU */
971 		error = EMSGSIZE;
972 		in6_ifstat_inc(ifp, ifs6_out_fragfail);
973 		goto bad;
974 	} else if (ip6->ip6_plen == 0) {
975 		/* jumbo payload cannot be fragmented */
976 		error = EMSGSIZE;
977 		in6_ifstat_inc(ifp, ifs6_out_fragfail);
978 		goto bad;
979 	} else {
980 		u_char nextproto;
981 
982 		/*
983 		 * Too large for the destination or interface;
984 		 * fragment if possible.
985 		 * Must be able to put at least 8 bytes per fragment.
986 		 */
987 		hlen = unfragpartlen;
988 		if (mtu > IPV6_MAXPACKET)
989 			mtu = IPV6_MAXPACKET;
990 
991 		len = (mtu - hlen - sizeof(struct ip6_frag)) & ~7;
992 		if (len < 8) {
993 			error = EMSGSIZE;
994 			in6_ifstat_inc(ifp, ifs6_out_fragfail);
995 			goto bad;
996 		}
997 
998 		/*
999 		 * If the interface will not calculate checksums on
1000 		 * fragmented packets, then do it here.
1001 		 * XXX-BZ handle the hw offloading case.  Need flags.
1002 		 */
1003 		if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
1004 			in6_delayed_cksum(m, plen, hlen);
1005 			m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA_IPV6;
1006 		}
1007 #ifdef SCTP
1008 		if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6) {
1009 			sctp_delayed_cksum(m, hlen);
1010 			m->m_pkthdr.csum_flags &= ~CSUM_SCTP_IPV6;
1011 		}
1012 #endif
1013 		/*
1014 		 * Change the next header field of the last header in the
1015 		 * unfragmentable part.
1016 		 */
1017 		if (exthdrs.ip6e_rthdr) {
1018 			nextproto = *mtod(exthdrs.ip6e_rthdr, u_char *);
1019 			*mtod(exthdrs.ip6e_rthdr, u_char *) = IPPROTO_FRAGMENT;
1020 		} else if (exthdrs.ip6e_dest1) {
1021 			nextproto = *mtod(exthdrs.ip6e_dest1, u_char *);
1022 			*mtod(exthdrs.ip6e_dest1, u_char *) = IPPROTO_FRAGMENT;
1023 		} else if (exthdrs.ip6e_hbh) {
1024 			nextproto = *mtod(exthdrs.ip6e_hbh, u_char *);
1025 			*mtod(exthdrs.ip6e_hbh, u_char *) = IPPROTO_FRAGMENT;
1026 		} else {
1027 			nextproto = ip6->ip6_nxt;
1028 			ip6->ip6_nxt = IPPROTO_FRAGMENT;
1029 		}
1030 
1031 		/*
1032 		 * Loop through length of segment after first fragment,
1033 		 * make new header and copy data of each part and link onto
1034 		 * chain.
1035 		 */
1036 		m0 = m;
1037 		id = htonl(ip6_randomid());
1038 		if ((error = ip6_fragment(ifp, m, hlen, nextproto, len, id)))
1039 			goto sendorfree;
1040 
1041 		in6_ifstat_inc(ifp, ifs6_out_fragok);
1042 	}
1043 
1044 	/*
1045 	 * Remove leading garbages.
1046 	 */
1047 sendorfree:
1048 	m = m0->m_nextpkt;
1049 	m0->m_nextpkt = 0;
1050 	m_freem(m0);
1051 	for (m0 = m; m; m = m0) {
1052 		m0 = m->m_nextpkt;
1053 		m->m_nextpkt = 0;
1054 		if (error == 0) {
1055 			/* Record statistics for this interface address. */
1056 			if (ia) {
1057 				counter_u64_add(ia->ia_ifa.ifa_opackets, 1);
1058 				counter_u64_add(ia->ia_ifa.ifa_obytes,
1059 				    m->m_pkthdr.len);
1060 			}
1061 #ifdef RATELIMIT
1062 			if (inp != NULL) {
1063 				if (inp->inp_flags2 & INP_RATE_LIMIT_CHANGED)
1064 					in_pcboutput_txrtlmt(inp, ifp, m);
1065 				/* stamp send tag on mbuf */
1066 				m->m_pkthdr.snd_tag = inp->inp_snd_tag;
1067 			} else {
1068 				m->m_pkthdr.snd_tag = NULL;
1069 			}
1070 #endif
1071 			error = nd6_output_ifp(ifp, origifp, m, dst,
1072 			    (struct route *)ro);
1073 #ifdef RATELIMIT
1074 			/* check for route change */
1075 			if (error == EAGAIN)
1076 				in_pcboutput_eagain(inp);
1077 #endif
1078 		} else
1079 			m_freem(m);
1080 	}
1081 
1082 	if (error == 0)
1083 		IP6STAT_INC(ip6s_fragmented);
1084 
1085 done:
1086 	if (ro == &ip6route)
1087 		RO_RTFREE(ro);
1088 	return (error);
1089 
1090 freehdrs:
1091 	m_freem(exthdrs.ip6e_hbh);	/* m_freem will check if mbuf is 0 */
1092 	m_freem(exthdrs.ip6e_dest1);
1093 	m_freem(exthdrs.ip6e_rthdr);
1094 	m_freem(exthdrs.ip6e_dest2);
1095 	/* FALLTHROUGH */
1096 bad:
1097 	if (m)
1098 		m_freem(m);
1099 	goto done;
1100 }
1101 
1102 static int
1103 ip6_copyexthdr(struct mbuf **mp, caddr_t hdr, int hlen)
1104 {
1105 	struct mbuf *m;
1106 
1107 	if (hlen > MCLBYTES)
1108 		return (ENOBUFS); /* XXX */
1109 
1110 	if (hlen > MLEN)
1111 		m = m_getcl(M_NOWAIT, MT_DATA, 0);
1112 	else
1113 		m = m_get(M_NOWAIT, MT_DATA);
1114 	if (m == NULL)
1115 		return (ENOBUFS);
1116 	m->m_len = hlen;
1117 	if (hdr)
1118 		bcopy(hdr, mtod(m, caddr_t), hlen);
1119 
1120 	*mp = m;
1121 	return (0);
1122 }
1123 
1124 /*
1125  * Insert jumbo payload option.
1126  */
1127 static int
1128 ip6_insert_jumboopt(struct ip6_exthdrs *exthdrs, u_int32_t plen)
1129 {
1130 	struct mbuf *mopt;
1131 	u_char *optbuf;
1132 	u_int32_t v;
1133 
1134 #define JUMBOOPTLEN	8	/* length of jumbo payload option and padding */
1135 
1136 	/*
1137 	 * If there is no hop-by-hop options header, allocate new one.
1138 	 * If there is one but it doesn't have enough space to store the
1139 	 * jumbo payload option, allocate a cluster to store the whole options.
1140 	 * Otherwise, use it to store the options.
1141 	 */
1142 	if (exthdrs->ip6e_hbh == NULL) {
1143 		mopt = m_get(M_NOWAIT, MT_DATA);
1144 		if (mopt == NULL)
1145 			return (ENOBUFS);
1146 		mopt->m_len = JUMBOOPTLEN;
1147 		optbuf = mtod(mopt, u_char *);
1148 		optbuf[1] = 0;	/* = ((JUMBOOPTLEN) >> 3) - 1 */
1149 		exthdrs->ip6e_hbh = mopt;
1150 	} else {
1151 		struct ip6_hbh *hbh;
1152 
1153 		mopt = exthdrs->ip6e_hbh;
1154 		if (M_TRAILINGSPACE(mopt) < JUMBOOPTLEN) {
1155 			/*
1156 			 * XXX assumption:
1157 			 * - exthdrs->ip6e_hbh is not referenced from places
1158 			 *   other than exthdrs.
1159 			 * - exthdrs->ip6e_hbh is not an mbuf chain.
1160 			 */
1161 			int oldoptlen = mopt->m_len;
1162 			struct mbuf *n;
1163 
1164 			/*
1165 			 * XXX: give up if the whole (new) hbh header does
1166 			 * not fit even in an mbuf cluster.
1167 			 */
1168 			if (oldoptlen + JUMBOOPTLEN > MCLBYTES)
1169 				return (ENOBUFS);
1170 
1171 			/*
1172 			 * As a consequence, we must always prepare a cluster
1173 			 * at this point.
1174 			 */
1175 			n = m_getcl(M_NOWAIT, MT_DATA, 0);
1176 			if (n == NULL)
1177 				return (ENOBUFS);
1178 			n->m_len = oldoptlen + JUMBOOPTLEN;
1179 			bcopy(mtod(mopt, caddr_t), mtod(n, caddr_t),
1180 			    oldoptlen);
1181 			optbuf = mtod(n, caddr_t) + oldoptlen;
1182 			m_freem(mopt);
1183 			mopt = exthdrs->ip6e_hbh = n;
1184 		} else {
1185 			optbuf = mtod(mopt, u_char *) + mopt->m_len;
1186 			mopt->m_len += JUMBOOPTLEN;
1187 		}
1188 		optbuf[0] = IP6OPT_PADN;
1189 		optbuf[1] = 1;
1190 
1191 		/*
1192 		 * Adjust the header length according to the pad and
1193 		 * the jumbo payload option.
1194 		 */
1195 		hbh = mtod(mopt, struct ip6_hbh *);
1196 		hbh->ip6h_len += (JUMBOOPTLEN >> 3);
1197 	}
1198 
1199 	/* fill in the option. */
1200 	optbuf[2] = IP6OPT_JUMBO;
1201 	optbuf[3] = 4;
1202 	v = (u_int32_t)htonl(plen + JUMBOOPTLEN);
1203 	bcopy(&v, &optbuf[4], sizeof(u_int32_t));
1204 
1205 	/* finally, adjust the packet header length */
1206 	exthdrs->ip6e_ip6->m_pkthdr.len += JUMBOOPTLEN;
1207 
1208 	return (0);
1209 #undef JUMBOOPTLEN
1210 }
1211 
1212 /*
1213  * Insert fragment header and copy unfragmentable header portions.
1214  */
1215 static int
1216 ip6_insertfraghdr(struct mbuf *m0, struct mbuf *m, int hlen,
1217     struct ip6_frag **frghdrp)
1218 {
1219 	struct mbuf *n, *mlast;
1220 
1221 	if (hlen > sizeof(struct ip6_hdr)) {
1222 		n = m_copym(m0, sizeof(struct ip6_hdr),
1223 		    hlen - sizeof(struct ip6_hdr), M_NOWAIT);
1224 		if (n == NULL)
1225 			return (ENOBUFS);
1226 		m->m_next = n;
1227 	} else
1228 		n = m;
1229 
1230 	/* Search for the last mbuf of unfragmentable part. */
1231 	for (mlast = n; mlast->m_next; mlast = mlast->m_next)
1232 		;
1233 
1234 	if (M_WRITABLE(mlast) &&
1235 	    M_TRAILINGSPACE(mlast) >= sizeof(struct ip6_frag)) {
1236 		/* use the trailing space of the last mbuf for the fragment hdr */
1237 		*frghdrp = (struct ip6_frag *)(mtod(mlast, caddr_t) +
1238 		    mlast->m_len);
1239 		mlast->m_len += sizeof(struct ip6_frag);
1240 		m->m_pkthdr.len += sizeof(struct ip6_frag);
1241 	} else {
1242 		/* allocate a new mbuf for the fragment header */
1243 		struct mbuf *mfrg;
1244 
1245 		mfrg = m_get(M_NOWAIT, MT_DATA);
1246 		if (mfrg == NULL)
1247 			return (ENOBUFS);
1248 		mfrg->m_len = sizeof(struct ip6_frag);
1249 		*frghdrp = mtod(mfrg, struct ip6_frag *);
1250 		mlast->m_next = mfrg;
1251 	}
1252 
1253 	return (0);
1254 }
1255 
1256 /*
1257  * Calculates IPv6 path mtu for destination @dst.
1258  * Resulting MTU is stored in @mtup.
1259  *
1260  * Returns 0 on success.
1261  */
1262 static int
1263 ip6_getpmtu_ctl(u_int fibnum, const struct in6_addr *dst, u_long *mtup)
1264 {
1265 	struct nhop6_extended nh6;
1266 	struct in6_addr kdst;
1267 	uint32_t scopeid;
1268 	struct ifnet *ifp;
1269 	u_long mtu;
1270 	int error;
1271 
1272 	in6_splitscope(dst, &kdst, &scopeid);
1273 	if (fib6_lookup_nh_ext(fibnum, &kdst, scopeid, NHR_REF, 0, &nh6) != 0)
1274 		return (EHOSTUNREACH);
1275 
1276 	ifp = nh6.nh_ifp;
1277 	mtu = nh6.nh_mtu;
1278 
1279 	error = ip6_calcmtu(ifp, dst, mtu, mtup, NULL, 0);
1280 	fib6_free_nh_ext(fibnum, &nh6);
1281 
1282 	return (error);
1283 }
1284 
1285 /*
1286  * Calculates IPv6 path MTU for @dst based on transmit @ifp,
1287  * and cached data in @ro_pmtu.
1288  * MTU from (successful) route lookup is saved (along with dst)
1289  * inside @ro_pmtu to avoid subsequent route lookups after packet
1290  * filter processing.
1291  *
1292  * Stores mtu and always-frag value into @mtup and @alwaysfragp.
1293  * Returns 0 on success.
1294  */
1295 static int
1296 ip6_getpmtu(struct route_in6 *ro_pmtu, int do_lookup,
1297     struct ifnet *ifp, const struct in6_addr *dst, u_long *mtup,
1298     int *alwaysfragp, u_int fibnum, u_int proto)
1299 {
1300 	struct nhop6_basic nh6;
1301 	struct in6_addr kdst;
1302 	uint32_t scopeid;
1303 	struct sockaddr_in6 *sa6_dst;
1304 	u_long mtu;
1305 
1306 	mtu = 0;
1307 	if (do_lookup) {
1308 
1309 		/*
1310 		 * Here ro_pmtu has final destination address, while
1311 		 * ro might represent immediate destination.
1312 		 * Use ro_pmtu destination since mtu might differ.
1313 		 */
1314 		sa6_dst = (struct sockaddr_in6 *)&ro_pmtu->ro_dst;
1315 		if (!IN6_ARE_ADDR_EQUAL(&sa6_dst->sin6_addr, dst))
1316 			ro_pmtu->ro_mtu = 0;
1317 
1318 		if (ro_pmtu->ro_mtu == 0) {
1319 			bzero(sa6_dst, sizeof(*sa6_dst));
1320 			sa6_dst->sin6_family = AF_INET6;
1321 			sa6_dst->sin6_len = sizeof(struct sockaddr_in6);
1322 			sa6_dst->sin6_addr = *dst;
1323 
1324 			in6_splitscope(dst, &kdst, &scopeid);
1325 			if (fib6_lookup_nh_basic(fibnum, &kdst, scopeid, 0, 0,
1326 			    &nh6) == 0)
1327 				ro_pmtu->ro_mtu = nh6.nh_mtu;
1328 		}
1329 
1330 		mtu = ro_pmtu->ro_mtu;
1331 	}
1332 
1333 	if (ro_pmtu->ro_rt)
1334 		mtu = ro_pmtu->ro_rt->rt_mtu;
1335 
1336 	return (ip6_calcmtu(ifp, dst, mtu, mtup, alwaysfragp, proto));
1337 }
1338 
1339 /*
1340  * Calculate MTU based on transmit @ifp, route mtu @rt_mtu and
1341  * hostcache data for @dst.
1342  * Stores mtu and always-frag value into @mtup and @alwaysfragp.
1343  *
1344  * Returns 0 on success.
1345  */
1346 static int
1347 ip6_calcmtu(struct ifnet *ifp, const struct in6_addr *dst, u_long rt_mtu,
1348     u_long *mtup, int *alwaysfragp, u_int proto)
1349 {
1350 	u_long mtu = 0;
1351 	int alwaysfrag = 0;
1352 	int error = 0;
1353 
1354 	if (rt_mtu > 0) {
1355 		u_int32_t ifmtu;
1356 		struct in_conninfo inc;
1357 
1358 		bzero(&inc, sizeof(inc));
1359 		inc.inc_flags |= INC_ISIPV6;
1360 		inc.inc6_faddr = *dst;
1361 
1362 		ifmtu = IN6_LINKMTU(ifp);
1363 
1364 		/* TCP is known to react to pmtu changes so skip hc */
1365 		if (proto != IPPROTO_TCP)
1366 			mtu = tcp_hc_getmtu(&inc);
1367 
1368 		if (mtu)
1369 			mtu = min(mtu, rt_mtu);
1370 		else
1371 			mtu = rt_mtu;
1372 		if (mtu == 0)
1373 			mtu = ifmtu;
1374 		else if (mtu < IPV6_MMTU) {
1375 			/*
1376 			 * RFC2460 section 5, last paragraph:
1377 			 * if we record ICMPv6 too big message with
1378 			 * mtu < IPV6_MMTU, transmit packets sized IPV6_MMTU
1379 			 * or smaller, with framgent header attached.
1380 			 * (fragment header is needed regardless from the
1381 			 * packet size, for translators to identify packets)
1382 			 */
1383 			alwaysfrag = 1;
1384 			mtu = IPV6_MMTU;
1385 		}
1386 	} else if (ifp) {
1387 		mtu = IN6_LINKMTU(ifp);
1388 	} else
1389 		error = EHOSTUNREACH; /* XXX */
1390 
1391 	*mtup = mtu;
1392 	if (alwaysfragp)
1393 		*alwaysfragp = alwaysfrag;
1394 	return (error);
1395 }
1396 
1397 /*
1398  * IP6 socket option processing.
1399  */
1400 int
1401 ip6_ctloutput(struct socket *so, struct sockopt *sopt)
1402 {
1403 	int optdatalen, uproto;
1404 	void *optdata;
1405 	struct inpcb *in6p = sotoinpcb(so);
1406 	int error, optval;
1407 	int level, op, optname;
1408 	int optlen;
1409 	struct thread *td;
1410 #ifdef	RSS
1411 	uint32_t rss_bucket;
1412 	int retval;
1413 #endif
1414 
1415 /*
1416  * Don't use more than a quarter of mbuf clusters.  N.B.:
1417  * nmbclusters is an int, but nmbclusters * MCLBYTES may overflow
1418  * on LP64 architectures, so cast to u_long to avoid undefined
1419  * behavior.  ILP32 architectures cannot have nmbclusters
1420  * large enough to overflow for other reasons.
1421  */
1422 #define IPV6_PKTOPTIONS_MBUF_LIMIT	((u_long)nmbclusters * MCLBYTES / 4)
1423 
1424 	level = sopt->sopt_level;
1425 	op = sopt->sopt_dir;
1426 	optname = sopt->sopt_name;
1427 	optlen = sopt->sopt_valsize;
1428 	td = sopt->sopt_td;
1429 	error = 0;
1430 	optval = 0;
1431 	uproto = (int)so->so_proto->pr_protocol;
1432 
1433 	if (level != IPPROTO_IPV6) {
1434 		error = EINVAL;
1435 
1436 		if (sopt->sopt_level == SOL_SOCKET &&
1437 		    sopt->sopt_dir == SOPT_SET) {
1438 			switch (sopt->sopt_name) {
1439 			case SO_REUSEADDR:
1440 				INP_WLOCK(in6p);
1441 				if ((so->so_options & SO_REUSEADDR) != 0)
1442 					in6p->inp_flags2 |= INP_REUSEADDR;
1443 				else
1444 					in6p->inp_flags2 &= ~INP_REUSEADDR;
1445 				INP_WUNLOCK(in6p);
1446 				error = 0;
1447 				break;
1448 			case SO_REUSEPORT:
1449 				INP_WLOCK(in6p);
1450 				if ((so->so_options & SO_REUSEPORT) != 0)
1451 					in6p->inp_flags2 |= INP_REUSEPORT;
1452 				else
1453 					in6p->inp_flags2 &= ~INP_REUSEPORT;
1454 				INP_WUNLOCK(in6p);
1455 				error = 0;
1456 				break;
1457 			case SO_SETFIB:
1458 				INP_WLOCK(in6p);
1459 				in6p->inp_inc.inc_fibnum = so->so_fibnum;
1460 				INP_WUNLOCK(in6p);
1461 				error = 0;
1462 				break;
1463 			case SO_MAX_PACING_RATE:
1464 #ifdef RATELIMIT
1465 				INP_WLOCK(in6p);
1466 				in6p->inp_flags2 |= INP_RATE_LIMIT_CHANGED;
1467 				INP_WUNLOCK(in6p);
1468 				error = 0;
1469 #else
1470 				error = EOPNOTSUPP;
1471 #endif
1472 				break;
1473 			default:
1474 				break;
1475 			}
1476 		}
1477 	} else {		/* level == IPPROTO_IPV6 */
1478 		switch (op) {
1479 
1480 		case SOPT_SET:
1481 			switch (optname) {
1482 			case IPV6_2292PKTOPTIONS:
1483 #ifdef IPV6_PKTOPTIONS
1484 			case IPV6_PKTOPTIONS:
1485 #endif
1486 			{
1487 				struct mbuf *m;
1488 
1489 				if (optlen > IPV6_PKTOPTIONS_MBUF_LIMIT) {
1490 					printf("ip6_ctloutput: mbuf limit hit\n");
1491 					error = ENOBUFS;
1492 					break;
1493 				}
1494 
1495 				error = soopt_getm(sopt, &m); /* XXX */
1496 				if (error != 0)
1497 					break;
1498 				error = soopt_mcopyin(sopt, m); /* XXX */
1499 				if (error != 0)
1500 					break;
1501 				error = ip6_pcbopts(&in6p->in6p_outputopts,
1502 						    m, so, sopt);
1503 				m_freem(m); /* XXX */
1504 				break;
1505 			}
1506 
1507 			/*
1508 			 * Use of some Hop-by-Hop options or some
1509 			 * Destination options, might require special
1510 			 * privilege.  That is, normal applications
1511 			 * (without special privilege) might be forbidden
1512 			 * from setting certain options in outgoing packets,
1513 			 * and might never see certain options in received
1514 			 * packets. [RFC 2292 Section 6]
1515 			 * KAME specific note:
1516 			 *  KAME prevents non-privileged users from sending or
1517 			 *  receiving ANY hbh/dst options in order to avoid
1518 			 *  overhead of parsing options in the kernel.
1519 			 */
1520 			case IPV6_RECVHOPOPTS:
1521 			case IPV6_RECVDSTOPTS:
1522 			case IPV6_RECVRTHDRDSTOPTS:
1523 				if (td != NULL) {
1524 					error = priv_check(td,
1525 					    PRIV_NETINET_SETHDROPTS);
1526 					if (error)
1527 						break;
1528 				}
1529 				/* FALLTHROUGH */
1530 			case IPV6_UNICAST_HOPS:
1531 			case IPV6_HOPLIMIT:
1532 
1533 			case IPV6_RECVPKTINFO:
1534 			case IPV6_RECVHOPLIMIT:
1535 			case IPV6_RECVRTHDR:
1536 			case IPV6_RECVPATHMTU:
1537 			case IPV6_RECVTCLASS:
1538 			case IPV6_RECVFLOWID:
1539 #ifdef	RSS
1540 			case IPV6_RECVRSSBUCKETID:
1541 #endif
1542 			case IPV6_V6ONLY:
1543 			case IPV6_AUTOFLOWLABEL:
1544 			case IPV6_ORIGDSTADDR:
1545 			case IPV6_BINDANY:
1546 			case IPV6_BINDMULTI:
1547 #ifdef	RSS
1548 			case IPV6_RSS_LISTEN_BUCKET:
1549 #endif
1550 				if (optname == IPV6_BINDANY && td != NULL) {
1551 					error = priv_check(td,
1552 					    PRIV_NETINET_BINDANY);
1553 					if (error)
1554 						break;
1555 				}
1556 
1557 				if (optlen != sizeof(int)) {
1558 					error = EINVAL;
1559 					break;
1560 				}
1561 				error = sooptcopyin(sopt, &optval,
1562 					sizeof optval, sizeof optval);
1563 				if (error)
1564 					break;
1565 				switch (optname) {
1566 
1567 				case IPV6_UNICAST_HOPS:
1568 					if (optval < -1 || optval >= 256)
1569 						error = EINVAL;
1570 					else {
1571 						/* -1 = kernel default */
1572 						in6p->in6p_hops = optval;
1573 						if ((in6p->inp_vflag &
1574 						     INP_IPV4) != 0)
1575 							in6p->inp_ip_ttl = optval;
1576 					}
1577 					break;
1578 #define OPTSET(bit) \
1579 do { \
1580 	INP_WLOCK(in6p); \
1581 	if (optval) \
1582 		in6p->inp_flags |= (bit); \
1583 	else \
1584 		in6p->inp_flags &= ~(bit); \
1585 	INP_WUNLOCK(in6p); \
1586 } while (/*CONSTCOND*/ 0)
1587 #define OPTSET2292(bit) \
1588 do { \
1589 	INP_WLOCK(in6p); \
1590 	in6p->inp_flags |= IN6P_RFC2292; \
1591 	if (optval) \
1592 		in6p->inp_flags |= (bit); \
1593 	else \
1594 		in6p->inp_flags &= ~(bit); \
1595 	INP_WUNLOCK(in6p); \
1596 } while (/*CONSTCOND*/ 0)
1597 #define OPTBIT(bit) (in6p->inp_flags & (bit) ? 1 : 0)
1598 
1599 #define OPTSET2(bit, val) do {						\
1600 	INP_WLOCK(in6p);						\
1601 	if (val)							\
1602 		in6p->inp_flags2 |= bit;				\
1603 	else								\
1604 		in6p->inp_flags2 &= ~bit;				\
1605 	INP_WUNLOCK(in6p);						\
1606 } while (0)
1607 #define OPTBIT2(bit) (in6p->inp_flags2 & (bit) ? 1 : 0)
1608 
1609 				case IPV6_RECVPKTINFO:
1610 					/* cannot mix with RFC2292 */
1611 					if (OPTBIT(IN6P_RFC2292)) {
1612 						error = EINVAL;
1613 						break;
1614 					}
1615 					OPTSET(IN6P_PKTINFO);
1616 					break;
1617 
1618 				case IPV6_HOPLIMIT:
1619 				{
1620 					struct ip6_pktopts **optp;
1621 
1622 					/* cannot mix with RFC2292 */
1623 					if (OPTBIT(IN6P_RFC2292)) {
1624 						error = EINVAL;
1625 						break;
1626 					}
1627 					optp = &in6p->in6p_outputopts;
1628 					error = ip6_pcbopt(IPV6_HOPLIMIT,
1629 					    (u_char *)&optval, sizeof(optval),
1630 					    optp, (td != NULL) ? td->td_ucred :
1631 					    NULL, uproto);
1632 					break;
1633 				}
1634 
1635 				case IPV6_RECVHOPLIMIT:
1636 					/* cannot mix with RFC2292 */
1637 					if (OPTBIT(IN6P_RFC2292)) {
1638 						error = EINVAL;
1639 						break;
1640 					}
1641 					OPTSET(IN6P_HOPLIMIT);
1642 					break;
1643 
1644 				case IPV6_RECVHOPOPTS:
1645 					/* cannot mix with RFC2292 */
1646 					if (OPTBIT(IN6P_RFC2292)) {
1647 						error = EINVAL;
1648 						break;
1649 					}
1650 					OPTSET(IN6P_HOPOPTS);
1651 					break;
1652 
1653 				case IPV6_RECVDSTOPTS:
1654 					/* cannot mix with RFC2292 */
1655 					if (OPTBIT(IN6P_RFC2292)) {
1656 						error = EINVAL;
1657 						break;
1658 					}
1659 					OPTSET(IN6P_DSTOPTS);
1660 					break;
1661 
1662 				case IPV6_RECVRTHDRDSTOPTS:
1663 					/* cannot mix with RFC2292 */
1664 					if (OPTBIT(IN6P_RFC2292)) {
1665 						error = EINVAL;
1666 						break;
1667 					}
1668 					OPTSET(IN6P_RTHDRDSTOPTS);
1669 					break;
1670 
1671 				case IPV6_RECVRTHDR:
1672 					/* cannot mix with RFC2292 */
1673 					if (OPTBIT(IN6P_RFC2292)) {
1674 						error = EINVAL;
1675 						break;
1676 					}
1677 					OPTSET(IN6P_RTHDR);
1678 					break;
1679 
1680 				case IPV6_RECVPATHMTU:
1681 					/*
1682 					 * We ignore this option for TCP
1683 					 * sockets.
1684 					 * (RFC3542 leaves this case
1685 					 * unspecified.)
1686 					 */
1687 					if (uproto != IPPROTO_TCP)
1688 						OPTSET(IN6P_MTU);
1689 					break;
1690 
1691 				case IPV6_RECVFLOWID:
1692 					OPTSET2(INP_RECVFLOWID, optval);
1693 					break;
1694 
1695 #ifdef	RSS
1696 				case IPV6_RECVRSSBUCKETID:
1697 					OPTSET2(INP_RECVRSSBUCKETID, optval);
1698 					break;
1699 #endif
1700 
1701 				case IPV6_V6ONLY:
1702 					/*
1703 					 * make setsockopt(IPV6_V6ONLY)
1704 					 * available only prior to bind(2).
1705 					 * see ipng mailing list, Jun 22 2001.
1706 					 */
1707 					if (in6p->inp_lport ||
1708 					    !IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_laddr)) {
1709 						error = EINVAL;
1710 						break;
1711 					}
1712 					OPTSET(IN6P_IPV6_V6ONLY);
1713 					if (optval)
1714 						in6p->inp_vflag &= ~INP_IPV4;
1715 					else
1716 						in6p->inp_vflag |= INP_IPV4;
1717 					break;
1718 				case IPV6_RECVTCLASS:
1719 					/* cannot mix with RFC2292 XXX */
1720 					if (OPTBIT(IN6P_RFC2292)) {
1721 						error = EINVAL;
1722 						break;
1723 					}
1724 					OPTSET(IN6P_TCLASS);
1725 					break;
1726 				case IPV6_AUTOFLOWLABEL:
1727 					OPTSET(IN6P_AUTOFLOWLABEL);
1728 					break;
1729 
1730 				case IPV6_ORIGDSTADDR:
1731 					OPTSET2(INP_ORIGDSTADDR, optval);
1732 					break;
1733 				case IPV6_BINDANY:
1734 					OPTSET(INP_BINDANY);
1735 					break;
1736 
1737 				case IPV6_BINDMULTI:
1738 					OPTSET2(INP_BINDMULTI, optval);
1739 					break;
1740 #ifdef	RSS
1741 				case IPV6_RSS_LISTEN_BUCKET:
1742 					if ((optval >= 0) &&
1743 					    (optval < rss_getnumbuckets())) {
1744 						in6p->inp_rss_listen_bucket = optval;
1745 						OPTSET2(INP_RSS_BUCKET_SET, 1);
1746 					} else {
1747 						error = EINVAL;
1748 					}
1749 					break;
1750 #endif
1751 				}
1752 				break;
1753 
1754 			case IPV6_TCLASS:
1755 			case IPV6_DONTFRAG:
1756 			case IPV6_USE_MIN_MTU:
1757 			case IPV6_PREFER_TEMPADDR:
1758 				if (optlen != sizeof(optval)) {
1759 					error = EINVAL;
1760 					break;
1761 				}
1762 				error = sooptcopyin(sopt, &optval,
1763 					sizeof optval, sizeof optval);
1764 				if (error)
1765 					break;
1766 				{
1767 					struct ip6_pktopts **optp;
1768 					optp = &in6p->in6p_outputopts;
1769 					error = ip6_pcbopt(optname,
1770 					    (u_char *)&optval, sizeof(optval),
1771 					    optp, (td != NULL) ? td->td_ucred :
1772 					    NULL, uproto);
1773 					break;
1774 				}
1775 
1776 			case IPV6_2292PKTINFO:
1777 			case IPV6_2292HOPLIMIT:
1778 			case IPV6_2292HOPOPTS:
1779 			case IPV6_2292DSTOPTS:
1780 			case IPV6_2292RTHDR:
1781 				/* RFC 2292 */
1782 				if (optlen != sizeof(int)) {
1783 					error = EINVAL;
1784 					break;
1785 				}
1786 				error = sooptcopyin(sopt, &optval,
1787 					sizeof optval, sizeof optval);
1788 				if (error)
1789 					break;
1790 				switch (optname) {
1791 				case IPV6_2292PKTINFO:
1792 					OPTSET2292(IN6P_PKTINFO);
1793 					break;
1794 				case IPV6_2292HOPLIMIT:
1795 					OPTSET2292(IN6P_HOPLIMIT);
1796 					break;
1797 				case IPV6_2292HOPOPTS:
1798 					/*
1799 					 * Check super-user privilege.
1800 					 * See comments for IPV6_RECVHOPOPTS.
1801 					 */
1802 					if (td != NULL) {
1803 						error = priv_check(td,
1804 						    PRIV_NETINET_SETHDROPTS);
1805 						if (error)
1806 							return (error);
1807 					}
1808 					OPTSET2292(IN6P_HOPOPTS);
1809 					break;
1810 				case IPV6_2292DSTOPTS:
1811 					if (td != NULL) {
1812 						error = priv_check(td,
1813 						    PRIV_NETINET_SETHDROPTS);
1814 						if (error)
1815 							return (error);
1816 					}
1817 					OPTSET2292(IN6P_DSTOPTS|IN6P_RTHDRDSTOPTS); /* XXX */
1818 					break;
1819 				case IPV6_2292RTHDR:
1820 					OPTSET2292(IN6P_RTHDR);
1821 					break;
1822 				}
1823 				break;
1824 			case IPV6_PKTINFO:
1825 			case IPV6_HOPOPTS:
1826 			case IPV6_RTHDR:
1827 			case IPV6_DSTOPTS:
1828 			case IPV6_RTHDRDSTOPTS:
1829 			case IPV6_NEXTHOP:
1830 			{
1831 				/* new advanced API (RFC3542) */
1832 				u_char *optbuf;
1833 				u_char optbuf_storage[MCLBYTES];
1834 				int optlen;
1835 				struct ip6_pktopts **optp;
1836 
1837 				/* cannot mix with RFC2292 */
1838 				if (OPTBIT(IN6P_RFC2292)) {
1839 					error = EINVAL;
1840 					break;
1841 				}
1842 
1843 				/*
1844 				 * We only ensure valsize is not too large
1845 				 * here.  Further validation will be done
1846 				 * later.
1847 				 */
1848 				error = sooptcopyin(sopt, optbuf_storage,
1849 				    sizeof(optbuf_storage), 0);
1850 				if (error)
1851 					break;
1852 				optlen = sopt->sopt_valsize;
1853 				optbuf = optbuf_storage;
1854 				optp = &in6p->in6p_outputopts;
1855 				error = ip6_pcbopt(optname, optbuf, optlen,
1856 				    optp, (td != NULL) ? td->td_ucred : NULL,
1857 				    uproto);
1858 				break;
1859 			}
1860 #undef OPTSET
1861 
1862 			case IPV6_MULTICAST_IF:
1863 			case IPV6_MULTICAST_HOPS:
1864 			case IPV6_MULTICAST_LOOP:
1865 			case IPV6_JOIN_GROUP:
1866 			case IPV6_LEAVE_GROUP:
1867 			case IPV6_MSFILTER:
1868 			case MCAST_BLOCK_SOURCE:
1869 			case MCAST_UNBLOCK_SOURCE:
1870 			case MCAST_JOIN_GROUP:
1871 			case MCAST_LEAVE_GROUP:
1872 			case MCAST_JOIN_SOURCE_GROUP:
1873 			case MCAST_LEAVE_SOURCE_GROUP:
1874 				error = ip6_setmoptions(in6p, sopt);
1875 				break;
1876 
1877 			case IPV6_PORTRANGE:
1878 				error = sooptcopyin(sopt, &optval,
1879 				    sizeof optval, sizeof optval);
1880 				if (error)
1881 					break;
1882 
1883 				INP_WLOCK(in6p);
1884 				switch (optval) {
1885 				case IPV6_PORTRANGE_DEFAULT:
1886 					in6p->inp_flags &= ~(INP_LOWPORT);
1887 					in6p->inp_flags &= ~(INP_HIGHPORT);
1888 					break;
1889 
1890 				case IPV6_PORTRANGE_HIGH:
1891 					in6p->inp_flags &= ~(INP_LOWPORT);
1892 					in6p->inp_flags |= INP_HIGHPORT;
1893 					break;
1894 
1895 				case IPV6_PORTRANGE_LOW:
1896 					in6p->inp_flags &= ~(INP_HIGHPORT);
1897 					in6p->inp_flags |= INP_LOWPORT;
1898 					break;
1899 
1900 				default:
1901 					error = EINVAL;
1902 					break;
1903 				}
1904 				INP_WUNLOCK(in6p);
1905 				break;
1906 
1907 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
1908 			case IPV6_IPSEC_POLICY:
1909 				if (IPSEC_ENABLED(ipv6)) {
1910 					error = IPSEC_PCBCTL(ipv6, in6p, sopt);
1911 					break;
1912 				}
1913 				/* FALLTHROUGH */
1914 #endif /* IPSEC */
1915 
1916 			default:
1917 				error = ENOPROTOOPT;
1918 				break;
1919 			}
1920 			break;
1921 
1922 		case SOPT_GET:
1923 			switch (optname) {
1924 
1925 			case IPV6_2292PKTOPTIONS:
1926 #ifdef IPV6_PKTOPTIONS
1927 			case IPV6_PKTOPTIONS:
1928 #endif
1929 				/*
1930 				 * RFC3542 (effectively) deprecated the
1931 				 * semantics of the 2292-style pktoptions.
1932 				 * Since it was not reliable in nature (i.e.,
1933 				 * applications had to expect the lack of some
1934 				 * information after all), it would make sense
1935 				 * to simplify this part by always returning
1936 				 * empty data.
1937 				 */
1938 				sopt->sopt_valsize = 0;
1939 				break;
1940 
1941 			case IPV6_RECVHOPOPTS:
1942 			case IPV6_RECVDSTOPTS:
1943 			case IPV6_RECVRTHDRDSTOPTS:
1944 			case IPV6_UNICAST_HOPS:
1945 			case IPV6_RECVPKTINFO:
1946 			case IPV6_RECVHOPLIMIT:
1947 			case IPV6_RECVRTHDR:
1948 			case IPV6_RECVPATHMTU:
1949 
1950 			case IPV6_V6ONLY:
1951 			case IPV6_PORTRANGE:
1952 			case IPV6_RECVTCLASS:
1953 			case IPV6_AUTOFLOWLABEL:
1954 			case IPV6_BINDANY:
1955 			case IPV6_FLOWID:
1956 			case IPV6_FLOWTYPE:
1957 			case IPV6_RECVFLOWID:
1958 #ifdef	RSS
1959 			case IPV6_RSSBUCKETID:
1960 			case IPV6_RECVRSSBUCKETID:
1961 #endif
1962 			case IPV6_BINDMULTI:
1963 				switch (optname) {
1964 
1965 				case IPV6_RECVHOPOPTS:
1966 					optval = OPTBIT(IN6P_HOPOPTS);
1967 					break;
1968 
1969 				case IPV6_RECVDSTOPTS:
1970 					optval = OPTBIT(IN6P_DSTOPTS);
1971 					break;
1972 
1973 				case IPV6_RECVRTHDRDSTOPTS:
1974 					optval = OPTBIT(IN6P_RTHDRDSTOPTS);
1975 					break;
1976 
1977 				case IPV6_UNICAST_HOPS:
1978 					optval = in6p->in6p_hops;
1979 					break;
1980 
1981 				case IPV6_RECVPKTINFO:
1982 					optval = OPTBIT(IN6P_PKTINFO);
1983 					break;
1984 
1985 				case IPV6_RECVHOPLIMIT:
1986 					optval = OPTBIT(IN6P_HOPLIMIT);
1987 					break;
1988 
1989 				case IPV6_RECVRTHDR:
1990 					optval = OPTBIT(IN6P_RTHDR);
1991 					break;
1992 
1993 				case IPV6_RECVPATHMTU:
1994 					optval = OPTBIT(IN6P_MTU);
1995 					break;
1996 
1997 				case IPV6_V6ONLY:
1998 					optval = OPTBIT(IN6P_IPV6_V6ONLY);
1999 					break;
2000 
2001 				case IPV6_PORTRANGE:
2002 				    {
2003 					int flags;
2004 					flags = in6p->inp_flags;
2005 					if (flags & INP_HIGHPORT)
2006 						optval = IPV6_PORTRANGE_HIGH;
2007 					else if (flags & INP_LOWPORT)
2008 						optval = IPV6_PORTRANGE_LOW;
2009 					else
2010 						optval = 0;
2011 					break;
2012 				    }
2013 				case IPV6_RECVTCLASS:
2014 					optval = OPTBIT(IN6P_TCLASS);
2015 					break;
2016 
2017 				case IPV6_AUTOFLOWLABEL:
2018 					optval = OPTBIT(IN6P_AUTOFLOWLABEL);
2019 					break;
2020 
2021 				case IPV6_ORIGDSTADDR:
2022 					optval = OPTBIT2(INP_ORIGDSTADDR);
2023 					break;
2024 
2025 				case IPV6_BINDANY:
2026 					optval = OPTBIT(INP_BINDANY);
2027 					break;
2028 
2029 				case IPV6_FLOWID:
2030 					optval = in6p->inp_flowid;
2031 					break;
2032 
2033 				case IPV6_FLOWTYPE:
2034 					optval = in6p->inp_flowtype;
2035 					break;
2036 
2037 				case IPV6_RECVFLOWID:
2038 					optval = OPTBIT2(INP_RECVFLOWID);
2039 					break;
2040 #ifdef	RSS
2041 				case IPV6_RSSBUCKETID:
2042 					retval =
2043 					    rss_hash2bucket(in6p->inp_flowid,
2044 					    in6p->inp_flowtype,
2045 					    &rss_bucket);
2046 					if (retval == 0)
2047 						optval = rss_bucket;
2048 					else
2049 						error = EINVAL;
2050 					break;
2051 
2052 				case IPV6_RECVRSSBUCKETID:
2053 					optval = OPTBIT2(INP_RECVRSSBUCKETID);
2054 					break;
2055 #endif
2056 
2057 				case IPV6_BINDMULTI:
2058 					optval = OPTBIT2(INP_BINDMULTI);
2059 					break;
2060 
2061 				}
2062 				if (error)
2063 					break;
2064 				error = sooptcopyout(sopt, &optval,
2065 					sizeof optval);
2066 				break;
2067 
2068 			case IPV6_PATHMTU:
2069 			{
2070 				u_long pmtu = 0;
2071 				struct ip6_mtuinfo mtuinfo;
2072 
2073 				if (!(so->so_state & SS_ISCONNECTED))
2074 					return (ENOTCONN);
2075 				/*
2076 				 * XXX: we dot not consider the case of source
2077 				 * routing, or optional information to specify
2078 				 * the outgoing interface.
2079 				 */
2080 				error = ip6_getpmtu_ctl(so->so_fibnum,
2081 				    &in6p->in6p_faddr, &pmtu);
2082 				if (error)
2083 					break;
2084 				if (pmtu > IPV6_MAXPACKET)
2085 					pmtu = IPV6_MAXPACKET;
2086 
2087 				bzero(&mtuinfo, sizeof(mtuinfo));
2088 				mtuinfo.ip6m_mtu = (u_int32_t)pmtu;
2089 				optdata = (void *)&mtuinfo;
2090 				optdatalen = sizeof(mtuinfo);
2091 				error = sooptcopyout(sopt, optdata,
2092 				    optdatalen);
2093 				break;
2094 			}
2095 
2096 			case IPV6_2292PKTINFO:
2097 			case IPV6_2292HOPLIMIT:
2098 			case IPV6_2292HOPOPTS:
2099 			case IPV6_2292RTHDR:
2100 			case IPV6_2292DSTOPTS:
2101 				switch (optname) {
2102 				case IPV6_2292PKTINFO:
2103 					optval = OPTBIT(IN6P_PKTINFO);
2104 					break;
2105 				case IPV6_2292HOPLIMIT:
2106 					optval = OPTBIT(IN6P_HOPLIMIT);
2107 					break;
2108 				case IPV6_2292HOPOPTS:
2109 					optval = OPTBIT(IN6P_HOPOPTS);
2110 					break;
2111 				case IPV6_2292RTHDR:
2112 					optval = OPTBIT(IN6P_RTHDR);
2113 					break;
2114 				case IPV6_2292DSTOPTS:
2115 					optval = OPTBIT(IN6P_DSTOPTS|IN6P_RTHDRDSTOPTS);
2116 					break;
2117 				}
2118 				error = sooptcopyout(sopt, &optval,
2119 				    sizeof optval);
2120 				break;
2121 			case IPV6_PKTINFO:
2122 			case IPV6_HOPOPTS:
2123 			case IPV6_RTHDR:
2124 			case IPV6_DSTOPTS:
2125 			case IPV6_RTHDRDSTOPTS:
2126 			case IPV6_NEXTHOP:
2127 			case IPV6_TCLASS:
2128 			case IPV6_DONTFRAG:
2129 			case IPV6_USE_MIN_MTU:
2130 			case IPV6_PREFER_TEMPADDR:
2131 				error = ip6_getpcbopt(in6p->in6p_outputopts,
2132 				    optname, sopt);
2133 				break;
2134 
2135 			case IPV6_MULTICAST_IF:
2136 			case IPV6_MULTICAST_HOPS:
2137 			case IPV6_MULTICAST_LOOP:
2138 			case IPV6_MSFILTER:
2139 				error = ip6_getmoptions(in6p, sopt);
2140 				break;
2141 
2142 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
2143 			case IPV6_IPSEC_POLICY:
2144 				if (IPSEC_ENABLED(ipv6)) {
2145 					error = IPSEC_PCBCTL(ipv6, in6p, sopt);
2146 					break;
2147 				}
2148 				/* FALLTHROUGH */
2149 #endif /* IPSEC */
2150 			default:
2151 				error = ENOPROTOOPT;
2152 				break;
2153 			}
2154 			break;
2155 		}
2156 	}
2157 	return (error);
2158 }
2159 
2160 int
2161 ip6_raw_ctloutput(struct socket *so, struct sockopt *sopt)
2162 {
2163 	int error = 0, optval, optlen;
2164 	const int icmp6off = offsetof(struct icmp6_hdr, icmp6_cksum);
2165 	struct inpcb *in6p = sotoinpcb(so);
2166 	int level, op, optname;
2167 
2168 	level = sopt->sopt_level;
2169 	op = sopt->sopt_dir;
2170 	optname = sopt->sopt_name;
2171 	optlen = sopt->sopt_valsize;
2172 
2173 	if (level != IPPROTO_IPV6) {
2174 		return (EINVAL);
2175 	}
2176 
2177 	switch (optname) {
2178 	case IPV6_CHECKSUM:
2179 		/*
2180 		 * For ICMPv6 sockets, no modification allowed for checksum
2181 		 * offset, permit "no change" values to help existing apps.
2182 		 *
2183 		 * RFC3542 says: "An attempt to set IPV6_CHECKSUM
2184 		 * for an ICMPv6 socket will fail."
2185 		 * The current behavior does not meet RFC3542.
2186 		 */
2187 		switch (op) {
2188 		case SOPT_SET:
2189 			if (optlen != sizeof(int)) {
2190 				error = EINVAL;
2191 				break;
2192 			}
2193 			error = sooptcopyin(sopt, &optval, sizeof(optval),
2194 					    sizeof(optval));
2195 			if (error)
2196 				break;
2197 			if ((optval % 2) != 0) {
2198 				/* the API assumes even offset values */
2199 				error = EINVAL;
2200 			} else if (so->so_proto->pr_protocol ==
2201 			    IPPROTO_ICMPV6) {
2202 				if (optval != icmp6off)
2203 					error = EINVAL;
2204 			} else
2205 				in6p->in6p_cksum = optval;
2206 			break;
2207 
2208 		case SOPT_GET:
2209 			if (so->so_proto->pr_protocol == IPPROTO_ICMPV6)
2210 				optval = icmp6off;
2211 			else
2212 				optval = in6p->in6p_cksum;
2213 
2214 			error = sooptcopyout(sopt, &optval, sizeof(optval));
2215 			break;
2216 
2217 		default:
2218 			error = EINVAL;
2219 			break;
2220 		}
2221 		break;
2222 
2223 	default:
2224 		error = ENOPROTOOPT;
2225 		break;
2226 	}
2227 
2228 	return (error);
2229 }
2230 
2231 /*
2232  * Set up IP6 options in pcb for insertion in output packets or
2233  * specifying behavior of outgoing packets.
2234  */
2235 static int
2236 ip6_pcbopts(struct ip6_pktopts **pktopt, struct mbuf *m,
2237     struct socket *so, struct sockopt *sopt)
2238 {
2239 	struct ip6_pktopts *opt = *pktopt;
2240 	int error = 0;
2241 	struct thread *td = sopt->sopt_td;
2242 
2243 	/* turn off any old options. */
2244 	if (opt) {
2245 #ifdef DIAGNOSTIC
2246 		if (opt->ip6po_pktinfo || opt->ip6po_nexthop ||
2247 		    opt->ip6po_hbh || opt->ip6po_dest1 || opt->ip6po_dest2 ||
2248 		    opt->ip6po_rhinfo.ip6po_rhi_rthdr)
2249 			printf("ip6_pcbopts: all specified options are cleared.\n");
2250 #endif
2251 		ip6_clearpktopts(opt, -1);
2252 	} else
2253 		opt = malloc(sizeof(*opt), M_IP6OPT, M_WAITOK);
2254 	*pktopt = NULL;
2255 
2256 	if (!m || m->m_len == 0) {
2257 		/*
2258 		 * Only turning off any previous options, regardless of
2259 		 * whether the opt is just created or given.
2260 		 */
2261 		free(opt, M_IP6OPT);
2262 		return (0);
2263 	}
2264 
2265 	/*  set options specified by user. */
2266 	if ((error = ip6_setpktopts(m, opt, NULL, (td != NULL) ?
2267 	    td->td_ucred : NULL, so->so_proto->pr_protocol)) != 0) {
2268 		ip6_clearpktopts(opt, -1); /* XXX: discard all options */
2269 		free(opt, M_IP6OPT);
2270 		return (error);
2271 	}
2272 	*pktopt = opt;
2273 	return (0);
2274 }
2275 
2276 /*
2277  * initialize ip6_pktopts.  beware that there are non-zero default values in
2278  * the struct.
2279  */
2280 void
2281 ip6_initpktopts(struct ip6_pktopts *opt)
2282 {
2283 
2284 	bzero(opt, sizeof(*opt));
2285 	opt->ip6po_hlim = -1;	/* -1 means default hop limit */
2286 	opt->ip6po_tclass = -1;	/* -1 means default traffic class */
2287 	opt->ip6po_minmtu = IP6PO_MINMTU_MCASTONLY;
2288 	opt->ip6po_prefer_tempaddr = IP6PO_TEMPADDR_SYSTEM;
2289 }
2290 
2291 static int
2292 ip6_pcbopt(int optname, u_char *buf, int len, struct ip6_pktopts **pktopt,
2293     struct ucred *cred, int uproto)
2294 {
2295 	struct ip6_pktopts *opt;
2296 
2297 	if (*pktopt == NULL) {
2298 		*pktopt = malloc(sizeof(struct ip6_pktopts), M_IP6OPT,
2299 		    M_WAITOK);
2300 		ip6_initpktopts(*pktopt);
2301 	}
2302 	opt = *pktopt;
2303 
2304 	return (ip6_setpktopt(optname, buf, len, opt, cred, 1, 0, uproto));
2305 }
2306 
2307 static int
2308 ip6_getpcbopt(struct ip6_pktopts *pktopt, int optname, struct sockopt *sopt)
2309 {
2310 	void *optdata = NULL;
2311 	int optdatalen = 0;
2312 	struct ip6_ext *ip6e;
2313 	int error = 0;
2314 	struct in6_pktinfo null_pktinfo;
2315 	int deftclass = 0, on;
2316 	int defminmtu = IP6PO_MINMTU_MCASTONLY;
2317 	int defpreftemp = IP6PO_TEMPADDR_SYSTEM;
2318 
2319 	switch (optname) {
2320 	case IPV6_PKTINFO:
2321 		optdata = (void *)&null_pktinfo;
2322 		if (pktopt && pktopt->ip6po_pktinfo) {
2323 			bcopy(pktopt->ip6po_pktinfo, &null_pktinfo,
2324 			    sizeof(null_pktinfo));
2325 			in6_clearscope(&null_pktinfo.ipi6_addr);
2326 		} else {
2327 			/* XXX: we don't have to do this every time... */
2328 			bzero(&null_pktinfo, sizeof(null_pktinfo));
2329 		}
2330 		optdatalen = sizeof(struct in6_pktinfo);
2331 		break;
2332 	case IPV6_TCLASS:
2333 		if (pktopt && pktopt->ip6po_tclass >= 0)
2334 			optdata = (void *)&pktopt->ip6po_tclass;
2335 		else
2336 			optdata = (void *)&deftclass;
2337 		optdatalen = sizeof(int);
2338 		break;
2339 	case IPV6_HOPOPTS:
2340 		if (pktopt && pktopt->ip6po_hbh) {
2341 			optdata = (void *)pktopt->ip6po_hbh;
2342 			ip6e = (struct ip6_ext *)pktopt->ip6po_hbh;
2343 			optdatalen = (ip6e->ip6e_len + 1) << 3;
2344 		}
2345 		break;
2346 	case IPV6_RTHDR:
2347 		if (pktopt && pktopt->ip6po_rthdr) {
2348 			optdata = (void *)pktopt->ip6po_rthdr;
2349 			ip6e = (struct ip6_ext *)pktopt->ip6po_rthdr;
2350 			optdatalen = (ip6e->ip6e_len + 1) << 3;
2351 		}
2352 		break;
2353 	case IPV6_RTHDRDSTOPTS:
2354 		if (pktopt && pktopt->ip6po_dest1) {
2355 			optdata = (void *)pktopt->ip6po_dest1;
2356 			ip6e = (struct ip6_ext *)pktopt->ip6po_dest1;
2357 			optdatalen = (ip6e->ip6e_len + 1) << 3;
2358 		}
2359 		break;
2360 	case IPV6_DSTOPTS:
2361 		if (pktopt && pktopt->ip6po_dest2) {
2362 			optdata = (void *)pktopt->ip6po_dest2;
2363 			ip6e = (struct ip6_ext *)pktopt->ip6po_dest2;
2364 			optdatalen = (ip6e->ip6e_len + 1) << 3;
2365 		}
2366 		break;
2367 	case IPV6_NEXTHOP:
2368 		if (pktopt && pktopt->ip6po_nexthop) {
2369 			optdata = (void *)pktopt->ip6po_nexthop;
2370 			optdatalen = pktopt->ip6po_nexthop->sa_len;
2371 		}
2372 		break;
2373 	case IPV6_USE_MIN_MTU:
2374 		if (pktopt)
2375 			optdata = (void *)&pktopt->ip6po_minmtu;
2376 		else
2377 			optdata = (void *)&defminmtu;
2378 		optdatalen = sizeof(int);
2379 		break;
2380 	case IPV6_DONTFRAG:
2381 		if (pktopt && ((pktopt->ip6po_flags) & IP6PO_DONTFRAG))
2382 			on = 1;
2383 		else
2384 			on = 0;
2385 		optdata = (void *)&on;
2386 		optdatalen = sizeof(on);
2387 		break;
2388 	case IPV6_PREFER_TEMPADDR:
2389 		if (pktopt)
2390 			optdata = (void *)&pktopt->ip6po_prefer_tempaddr;
2391 		else
2392 			optdata = (void *)&defpreftemp;
2393 		optdatalen = sizeof(int);
2394 		break;
2395 	default:		/* should not happen */
2396 #ifdef DIAGNOSTIC
2397 		panic("ip6_getpcbopt: unexpected option\n");
2398 #endif
2399 		return (ENOPROTOOPT);
2400 	}
2401 
2402 	error = sooptcopyout(sopt, optdata, optdatalen);
2403 
2404 	return (error);
2405 }
2406 
2407 void
2408 ip6_clearpktopts(struct ip6_pktopts *pktopt, int optname)
2409 {
2410 	if (pktopt == NULL)
2411 		return;
2412 
2413 	if (optname == -1 || optname == IPV6_PKTINFO) {
2414 		if (pktopt->ip6po_pktinfo)
2415 			free(pktopt->ip6po_pktinfo, M_IP6OPT);
2416 		pktopt->ip6po_pktinfo = NULL;
2417 	}
2418 	if (optname == -1 || optname == IPV6_HOPLIMIT)
2419 		pktopt->ip6po_hlim = -1;
2420 	if (optname == -1 || optname == IPV6_TCLASS)
2421 		pktopt->ip6po_tclass = -1;
2422 	if (optname == -1 || optname == IPV6_NEXTHOP) {
2423 		if (pktopt->ip6po_nextroute.ro_rt) {
2424 			RTFREE(pktopt->ip6po_nextroute.ro_rt);
2425 			pktopt->ip6po_nextroute.ro_rt = NULL;
2426 		}
2427 		if (pktopt->ip6po_nexthop)
2428 			free(pktopt->ip6po_nexthop, M_IP6OPT);
2429 		pktopt->ip6po_nexthop = NULL;
2430 	}
2431 	if (optname == -1 || optname == IPV6_HOPOPTS) {
2432 		if (pktopt->ip6po_hbh)
2433 			free(pktopt->ip6po_hbh, M_IP6OPT);
2434 		pktopt->ip6po_hbh = NULL;
2435 	}
2436 	if (optname == -1 || optname == IPV6_RTHDRDSTOPTS) {
2437 		if (pktopt->ip6po_dest1)
2438 			free(pktopt->ip6po_dest1, M_IP6OPT);
2439 		pktopt->ip6po_dest1 = NULL;
2440 	}
2441 	if (optname == -1 || optname == IPV6_RTHDR) {
2442 		if (pktopt->ip6po_rhinfo.ip6po_rhi_rthdr)
2443 			free(pktopt->ip6po_rhinfo.ip6po_rhi_rthdr, M_IP6OPT);
2444 		pktopt->ip6po_rhinfo.ip6po_rhi_rthdr = NULL;
2445 		if (pktopt->ip6po_route.ro_rt) {
2446 			RTFREE(pktopt->ip6po_route.ro_rt);
2447 			pktopt->ip6po_route.ro_rt = NULL;
2448 		}
2449 	}
2450 	if (optname == -1 || optname == IPV6_DSTOPTS) {
2451 		if (pktopt->ip6po_dest2)
2452 			free(pktopt->ip6po_dest2, M_IP6OPT);
2453 		pktopt->ip6po_dest2 = NULL;
2454 	}
2455 }
2456 
2457 #define PKTOPT_EXTHDRCPY(type) \
2458 do {\
2459 	if (src->type) {\
2460 		int hlen = (((struct ip6_ext *)src->type)->ip6e_len + 1) << 3;\
2461 		dst->type = malloc(hlen, M_IP6OPT, canwait);\
2462 		if (dst->type == NULL)\
2463 			goto bad;\
2464 		bcopy(src->type, dst->type, hlen);\
2465 	}\
2466 } while (/*CONSTCOND*/ 0)
2467 
2468 static int
2469 copypktopts(struct ip6_pktopts *dst, struct ip6_pktopts *src, int canwait)
2470 {
2471 	if (dst == NULL || src == NULL)  {
2472 		printf("ip6_clearpktopts: invalid argument\n");
2473 		return (EINVAL);
2474 	}
2475 
2476 	dst->ip6po_hlim = src->ip6po_hlim;
2477 	dst->ip6po_tclass = src->ip6po_tclass;
2478 	dst->ip6po_flags = src->ip6po_flags;
2479 	dst->ip6po_minmtu = src->ip6po_minmtu;
2480 	dst->ip6po_prefer_tempaddr = src->ip6po_prefer_tempaddr;
2481 	if (src->ip6po_pktinfo) {
2482 		dst->ip6po_pktinfo = malloc(sizeof(*dst->ip6po_pktinfo),
2483 		    M_IP6OPT, canwait);
2484 		if (dst->ip6po_pktinfo == NULL)
2485 			goto bad;
2486 		*dst->ip6po_pktinfo = *src->ip6po_pktinfo;
2487 	}
2488 	if (src->ip6po_nexthop) {
2489 		dst->ip6po_nexthop = malloc(src->ip6po_nexthop->sa_len,
2490 		    M_IP6OPT, canwait);
2491 		if (dst->ip6po_nexthop == NULL)
2492 			goto bad;
2493 		bcopy(src->ip6po_nexthop, dst->ip6po_nexthop,
2494 		    src->ip6po_nexthop->sa_len);
2495 	}
2496 	PKTOPT_EXTHDRCPY(ip6po_hbh);
2497 	PKTOPT_EXTHDRCPY(ip6po_dest1);
2498 	PKTOPT_EXTHDRCPY(ip6po_dest2);
2499 	PKTOPT_EXTHDRCPY(ip6po_rthdr); /* not copy the cached route */
2500 	return (0);
2501 
2502   bad:
2503 	ip6_clearpktopts(dst, -1);
2504 	return (ENOBUFS);
2505 }
2506 #undef PKTOPT_EXTHDRCPY
2507 
2508 struct ip6_pktopts *
2509 ip6_copypktopts(struct ip6_pktopts *src, int canwait)
2510 {
2511 	int error;
2512 	struct ip6_pktopts *dst;
2513 
2514 	dst = malloc(sizeof(*dst), M_IP6OPT, canwait);
2515 	if (dst == NULL)
2516 		return (NULL);
2517 	ip6_initpktopts(dst);
2518 
2519 	if ((error = copypktopts(dst, src, canwait)) != 0) {
2520 		free(dst, M_IP6OPT);
2521 		return (NULL);
2522 	}
2523 
2524 	return (dst);
2525 }
2526 
2527 void
2528 ip6_freepcbopts(struct ip6_pktopts *pktopt)
2529 {
2530 	if (pktopt == NULL)
2531 		return;
2532 
2533 	ip6_clearpktopts(pktopt, -1);
2534 
2535 	free(pktopt, M_IP6OPT);
2536 }
2537 
2538 /*
2539  * Set IPv6 outgoing packet options based on advanced API.
2540  */
2541 int
2542 ip6_setpktopts(struct mbuf *control, struct ip6_pktopts *opt,
2543     struct ip6_pktopts *stickyopt, struct ucred *cred, int uproto)
2544 {
2545 	struct cmsghdr *cm = NULL;
2546 
2547 	if (control == NULL || opt == NULL)
2548 		return (EINVAL);
2549 
2550 	ip6_initpktopts(opt);
2551 	if (stickyopt) {
2552 		int error;
2553 
2554 		/*
2555 		 * If stickyopt is provided, make a local copy of the options
2556 		 * for this particular packet, then override them by ancillary
2557 		 * objects.
2558 		 * XXX: copypktopts() does not copy the cached route to a next
2559 		 * hop (if any).  This is not very good in terms of efficiency,
2560 		 * but we can allow this since this option should be rarely
2561 		 * used.
2562 		 */
2563 		if ((error = copypktopts(opt, stickyopt, M_NOWAIT)) != 0)
2564 			return (error);
2565 	}
2566 
2567 	/*
2568 	 * XXX: Currently, we assume all the optional information is stored
2569 	 * in a single mbuf.
2570 	 */
2571 	if (control->m_next)
2572 		return (EINVAL);
2573 
2574 	for (; control->m_len > 0; control->m_data += CMSG_ALIGN(cm->cmsg_len),
2575 	    control->m_len -= CMSG_ALIGN(cm->cmsg_len)) {
2576 		int error;
2577 
2578 		if (control->m_len < CMSG_LEN(0))
2579 			return (EINVAL);
2580 
2581 		cm = mtod(control, struct cmsghdr *);
2582 		if (cm->cmsg_len == 0 || cm->cmsg_len > control->m_len)
2583 			return (EINVAL);
2584 		if (cm->cmsg_level != IPPROTO_IPV6)
2585 			continue;
2586 
2587 		error = ip6_setpktopt(cm->cmsg_type, CMSG_DATA(cm),
2588 		    cm->cmsg_len - CMSG_LEN(0), opt, cred, 0, 1, uproto);
2589 		if (error)
2590 			return (error);
2591 	}
2592 
2593 	return (0);
2594 }
2595 
2596 /*
2597  * Set a particular packet option, as a sticky option or an ancillary data
2598  * item.  "len" can be 0 only when it's a sticky option.
2599  * We have 4 cases of combination of "sticky" and "cmsg":
2600  * "sticky=0, cmsg=0": impossible
2601  * "sticky=0, cmsg=1": RFC2292 or RFC3542 ancillary data
2602  * "sticky=1, cmsg=0": RFC3542 socket option
2603  * "sticky=1, cmsg=1": RFC2292 socket option
2604  */
2605 static int
2606 ip6_setpktopt(int optname, u_char *buf, int len, struct ip6_pktopts *opt,
2607     struct ucred *cred, int sticky, int cmsg, int uproto)
2608 {
2609 	int minmtupolicy, preftemp;
2610 	int error;
2611 
2612 	if (!sticky && !cmsg) {
2613 #ifdef DIAGNOSTIC
2614 		printf("ip6_setpktopt: impossible case\n");
2615 #endif
2616 		return (EINVAL);
2617 	}
2618 
2619 	/*
2620 	 * IPV6_2292xxx is for backward compatibility to RFC2292, and should
2621 	 * not be specified in the context of RFC3542.  Conversely,
2622 	 * RFC3542 types should not be specified in the context of RFC2292.
2623 	 */
2624 	if (!cmsg) {
2625 		switch (optname) {
2626 		case IPV6_2292PKTINFO:
2627 		case IPV6_2292HOPLIMIT:
2628 		case IPV6_2292NEXTHOP:
2629 		case IPV6_2292HOPOPTS:
2630 		case IPV6_2292DSTOPTS:
2631 		case IPV6_2292RTHDR:
2632 		case IPV6_2292PKTOPTIONS:
2633 			return (ENOPROTOOPT);
2634 		}
2635 	}
2636 	if (sticky && cmsg) {
2637 		switch (optname) {
2638 		case IPV6_PKTINFO:
2639 		case IPV6_HOPLIMIT:
2640 		case IPV6_NEXTHOP:
2641 		case IPV6_HOPOPTS:
2642 		case IPV6_DSTOPTS:
2643 		case IPV6_RTHDRDSTOPTS:
2644 		case IPV6_RTHDR:
2645 		case IPV6_USE_MIN_MTU:
2646 		case IPV6_DONTFRAG:
2647 		case IPV6_TCLASS:
2648 		case IPV6_PREFER_TEMPADDR: /* XXX: not an RFC3542 option */
2649 			return (ENOPROTOOPT);
2650 		}
2651 	}
2652 
2653 	switch (optname) {
2654 	case IPV6_2292PKTINFO:
2655 	case IPV6_PKTINFO:
2656 	{
2657 		struct ifnet *ifp = NULL;
2658 		struct in6_pktinfo *pktinfo;
2659 
2660 		if (len != sizeof(struct in6_pktinfo))
2661 			return (EINVAL);
2662 
2663 		pktinfo = (struct in6_pktinfo *)buf;
2664 
2665 		/*
2666 		 * An application can clear any sticky IPV6_PKTINFO option by
2667 		 * doing a "regular" setsockopt with ipi6_addr being
2668 		 * in6addr_any and ipi6_ifindex being zero.
2669 		 * [RFC 3542, Section 6]
2670 		 */
2671 		if (optname == IPV6_PKTINFO && opt->ip6po_pktinfo &&
2672 		    pktinfo->ipi6_ifindex == 0 &&
2673 		    IN6_IS_ADDR_UNSPECIFIED(&pktinfo->ipi6_addr)) {
2674 			ip6_clearpktopts(opt, optname);
2675 			break;
2676 		}
2677 
2678 		if (uproto == IPPROTO_TCP && optname == IPV6_PKTINFO &&
2679 		    sticky && !IN6_IS_ADDR_UNSPECIFIED(&pktinfo->ipi6_addr)) {
2680 			return (EINVAL);
2681 		}
2682 		if (IN6_IS_ADDR_MULTICAST(&pktinfo->ipi6_addr))
2683 			return (EINVAL);
2684 		/* validate the interface index if specified. */
2685 		if (pktinfo->ipi6_ifindex > V_if_index)
2686 			 return (ENXIO);
2687 		if (pktinfo->ipi6_ifindex) {
2688 			ifp = ifnet_byindex(pktinfo->ipi6_ifindex);
2689 			if (ifp == NULL)
2690 				return (ENXIO);
2691 		}
2692 		if (ifp != NULL && (ifp->if_afdata[AF_INET6] == NULL ||
2693 		    (ND_IFINFO(ifp)->flags & ND6_IFF_IFDISABLED) != 0))
2694 			return (ENETDOWN);
2695 
2696 		if (ifp != NULL &&
2697 		    !IN6_IS_ADDR_UNSPECIFIED(&pktinfo->ipi6_addr)) {
2698 			struct in6_ifaddr *ia;
2699 
2700 			in6_setscope(&pktinfo->ipi6_addr, ifp, NULL);
2701 			ia = in6ifa_ifpwithaddr(ifp, &pktinfo->ipi6_addr);
2702 			if (ia == NULL)
2703 				return (EADDRNOTAVAIL);
2704 			ifa_free(&ia->ia_ifa);
2705 		}
2706 		/*
2707 		 * We store the address anyway, and let in6_selectsrc()
2708 		 * validate the specified address.  This is because ipi6_addr
2709 		 * may not have enough information about its scope zone, and
2710 		 * we may need additional information (such as outgoing
2711 		 * interface or the scope zone of a destination address) to
2712 		 * disambiguate the scope.
2713 		 * XXX: the delay of the validation may confuse the
2714 		 * application when it is used as a sticky option.
2715 		 */
2716 		if (opt->ip6po_pktinfo == NULL) {
2717 			opt->ip6po_pktinfo = malloc(sizeof(*pktinfo),
2718 			    M_IP6OPT, M_NOWAIT);
2719 			if (opt->ip6po_pktinfo == NULL)
2720 				return (ENOBUFS);
2721 		}
2722 		bcopy(pktinfo, opt->ip6po_pktinfo, sizeof(*pktinfo));
2723 		break;
2724 	}
2725 
2726 	case IPV6_2292HOPLIMIT:
2727 	case IPV6_HOPLIMIT:
2728 	{
2729 		int *hlimp;
2730 
2731 		/*
2732 		 * RFC 3542 deprecated the usage of sticky IPV6_HOPLIMIT
2733 		 * to simplify the ordering among hoplimit options.
2734 		 */
2735 		if (optname == IPV6_HOPLIMIT && sticky)
2736 			return (ENOPROTOOPT);
2737 
2738 		if (len != sizeof(int))
2739 			return (EINVAL);
2740 		hlimp = (int *)buf;
2741 		if (*hlimp < -1 || *hlimp > 255)
2742 			return (EINVAL);
2743 
2744 		opt->ip6po_hlim = *hlimp;
2745 		break;
2746 	}
2747 
2748 	case IPV6_TCLASS:
2749 	{
2750 		int tclass;
2751 
2752 		if (len != sizeof(int))
2753 			return (EINVAL);
2754 		tclass = *(int *)buf;
2755 		if (tclass < -1 || tclass > 255)
2756 			return (EINVAL);
2757 
2758 		opt->ip6po_tclass = tclass;
2759 		break;
2760 	}
2761 
2762 	case IPV6_2292NEXTHOP:
2763 	case IPV6_NEXTHOP:
2764 		if (cred != NULL) {
2765 			error = priv_check_cred(cred,
2766 			    PRIV_NETINET_SETHDROPTS, 0);
2767 			if (error)
2768 				return (error);
2769 		}
2770 
2771 		if (len == 0) {	/* just remove the option */
2772 			ip6_clearpktopts(opt, IPV6_NEXTHOP);
2773 			break;
2774 		}
2775 
2776 		/* check if cmsg_len is large enough for sa_len */
2777 		if (len < sizeof(struct sockaddr) || len < *buf)
2778 			return (EINVAL);
2779 
2780 		switch (((struct sockaddr *)buf)->sa_family) {
2781 		case AF_INET6:
2782 		{
2783 			struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)buf;
2784 			int error;
2785 
2786 			if (sa6->sin6_len != sizeof(struct sockaddr_in6))
2787 				return (EINVAL);
2788 
2789 			if (IN6_IS_ADDR_UNSPECIFIED(&sa6->sin6_addr) ||
2790 			    IN6_IS_ADDR_MULTICAST(&sa6->sin6_addr)) {
2791 				return (EINVAL);
2792 			}
2793 			if ((error = sa6_embedscope(sa6, V_ip6_use_defzone))
2794 			    != 0) {
2795 				return (error);
2796 			}
2797 			break;
2798 		}
2799 		case AF_LINK:	/* should eventually be supported */
2800 		default:
2801 			return (EAFNOSUPPORT);
2802 		}
2803 
2804 		/* turn off the previous option, then set the new option. */
2805 		ip6_clearpktopts(opt, IPV6_NEXTHOP);
2806 		opt->ip6po_nexthop = malloc(*buf, M_IP6OPT, M_NOWAIT);
2807 		if (opt->ip6po_nexthop == NULL)
2808 			return (ENOBUFS);
2809 		bcopy(buf, opt->ip6po_nexthop, *buf);
2810 		break;
2811 
2812 	case IPV6_2292HOPOPTS:
2813 	case IPV6_HOPOPTS:
2814 	{
2815 		struct ip6_hbh *hbh;
2816 		int hbhlen;
2817 
2818 		/*
2819 		 * XXX: We don't allow a non-privileged user to set ANY HbH
2820 		 * options, since per-option restriction has too much
2821 		 * overhead.
2822 		 */
2823 		if (cred != NULL) {
2824 			error = priv_check_cred(cred,
2825 			    PRIV_NETINET_SETHDROPTS, 0);
2826 			if (error)
2827 				return (error);
2828 		}
2829 
2830 		if (len == 0) {
2831 			ip6_clearpktopts(opt, IPV6_HOPOPTS);
2832 			break;	/* just remove the option */
2833 		}
2834 
2835 		/* message length validation */
2836 		if (len < sizeof(struct ip6_hbh))
2837 			return (EINVAL);
2838 		hbh = (struct ip6_hbh *)buf;
2839 		hbhlen = (hbh->ip6h_len + 1) << 3;
2840 		if (len != hbhlen)
2841 			return (EINVAL);
2842 
2843 		/* turn off the previous option, then set the new option. */
2844 		ip6_clearpktopts(opt, IPV6_HOPOPTS);
2845 		opt->ip6po_hbh = malloc(hbhlen, M_IP6OPT, M_NOWAIT);
2846 		if (opt->ip6po_hbh == NULL)
2847 			return (ENOBUFS);
2848 		bcopy(hbh, opt->ip6po_hbh, hbhlen);
2849 
2850 		break;
2851 	}
2852 
2853 	case IPV6_2292DSTOPTS:
2854 	case IPV6_DSTOPTS:
2855 	case IPV6_RTHDRDSTOPTS:
2856 	{
2857 		struct ip6_dest *dest, **newdest = NULL;
2858 		int destlen;
2859 
2860 		if (cred != NULL) { /* XXX: see the comment for IPV6_HOPOPTS */
2861 			error = priv_check_cred(cred,
2862 			    PRIV_NETINET_SETHDROPTS, 0);
2863 			if (error)
2864 				return (error);
2865 		}
2866 
2867 		if (len == 0) {
2868 			ip6_clearpktopts(opt, optname);
2869 			break;	/* just remove the option */
2870 		}
2871 
2872 		/* message length validation */
2873 		if (len < sizeof(struct ip6_dest))
2874 			return (EINVAL);
2875 		dest = (struct ip6_dest *)buf;
2876 		destlen = (dest->ip6d_len + 1) << 3;
2877 		if (len != destlen)
2878 			return (EINVAL);
2879 
2880 		/*
2881 		 * Determine the position that the destination options header
2882 		 * should be inserted; before or after the routing header.
2883 		 */
2884 		switch (optname) {
2885 		case IPV6_2292DSTOPTS:
2886 			/*
2887 			 * The old advacned API is ambiguous on this point.
2888 			 * Our approach is to determine the position based
2889 			 * according to the existence of a routing header.
2890 			 * Note, however, that this depends on the order of the
2891 			 * extension headers in the ancillary data; the 1st
2892 			 * part of the destination options header must appear
2893 			 * before the routing header in the ancillary data,
2894 			 * too.
2895 			 * RFC3542 solved the ambiguity by introducing
2896 			 * separate ancillary data or option types.
2897 			 */
2898 			if (opt->ip6po_rthdr == NULL)
2899 				newdest = &opt->ip6po_dest1;
2900 			else
2901 				newdest = &opt->ip6po_dest2;
2902 			break;
2903 		case IPV6_RTHDRDSTOPTS:
2904 			newdest = &opt->ip6po_dest1;
2905 			break;
2906 		case IPV6_DSTOPTS:
2907 			newdest = &opt->ip6po_dest2;
2908 			break;
2909 		}
2910 
2911 		/* turn off the previous option, then set the new option. */
2912 		ip6_clearpktopts(opt, optname);
2913 		*newdest = malloc(destlen, M_IP6OPT, M_NOWAIT);
2914 		if (*newdest == NULL)
2915 			return (ENOBUFS);
2916 		bcopy(dest, *newdest, destlen);
2917 
2918 		break;
2919 	}
2920 
2921 	case IPV6_2292RTHDR:
2922 	case IPV6_RTHDR:
2923 	{
2924 		struct ip6_rthdr *rth;
2925 		int rthlen;
2926 
2927 		if (len == 0) {
2928 			ip6_clearpktopts(opt, IPV6_RTHDR);
2929 			break;	/* just remove the option */
2930 		}
2931 
2932 		/* message length validation */
2933 		if (len < sizeof(struct ip6_rthdr))
2934 			return (EINVAL);
2935 		rth = (struct ip6_rthdr *)buf;
2936 		rthlen = (rth->ip6r_len + 1) << 3;
2937 		if (len != rthlen)
2938 			return (EINVAL);
2939 
2940 		switch (rth->ip6r_type) {
2941 		case IPV6_RTHDR_TYPE_0:
2942 			if (rth->ip6r_len == 0)	/* must contain one addr */
2943 				return (EINVAL);
2944 			if (rth->ip6r_len % 2) /* length must be even */
2945 				return (EINVAL);
2946 			if (rth->ip6r_len / 2 != rth->ip6r_segleft)
2947 				return (EINVAL);
2948 			break;
2949 		default:
2950 			return (EINVAL);	/* not supported */
2951 		}
2952 
2953 		/* turn off the previous option */
2954 		ip6_clearpktopts(opt, IPV6_RTHDR);
2955 		opt->ip6po_rthdr = malloc(rthlen, M_IP6OPT, M_NOWAIT);
2956 		if (opt->ip6po_rthdr == NULL)
2957 			return (ENOBUFS);
2958 		bcopy(rth, opt->ip6po_rthdr, rthlen);
2959 
2960 		break;
2961 	}
2962 
2963 	case IPV6_USE_MIN_MTU:
2964 		if (len != sizeof(int))
2965 			return (EINVAL);
2966 		minmtupolicy = *(int *)buf;
2967 		if (minmtupolicy != IP6PO_MINMTU_MCASTONLY &&
2968 		    minmtupolicy != IP6PO_MINMTU_DISABLE &&
2969 		    minmtupolicy != IP6PO_MINMTU_ALL) {
2970 			return (EINVAL);
2971 		}
2972 		opt->ip6po_minmtu = minmtupolicy;
2973 		break;
2974 
2975 	case IPV6_DONTFRAG:
2976 		if (len != sizeof(int))
2977 			return (EINVAL);
2978 
2979 		if (uproto == IPPROTO_TCP || *(int *)buf == 0) {
2980 			/*
2981 			 * we ignore this option for TCP sockets.
2982 			 * (RFC3542 leaves this case unspecified.)
2983 			 */
2984 			opt->ip6po_flags &= ~IP6PO_DONTFRAG;
2985 		} else
2986 			opt->ip6po_flags |= IP6PO_DONTFRAG;
2987 		break;
2988 
2989 	case IPV6_PREFER_TEMPADDR:
2990 		if (len != sizeof(int))
2991 			return (EINVAL);
2992 		preftemp = *(int *)buf;
2993 		if (preftemp != IP6PO_TEMPADDR_SYSTEM &&
2994 		    preftemp != IP6PO_TEMPADDR_NOTPREFER &&
2995 		    preftemp != IP6PO_TEMPADDR_PREFER) {
2996 			return (EINVAL);
2997 		}
2998 		opt->ip6po_prefer_tempaddr = preftemp;
2999 		break;
3000 
3001 	default:
3002 		return (ENOPROTOOPT);
3003 	} /* end of switch */
3004 
3005 	return (0);
3006 }
3007 
3008 /*
3009  * Routine called from ip6_output() to loop back a copy of an IP6 multicast
3010  * packet to the input queue of a specified interface.  Note that this
3011  * calls the output routine of the loopback "driver", but with an interface
3012  * pointer that might NOT be &loif -- easier than replicating that code here.
3013  */
3014 void
3015 ip6_mloopback(struct ifnet *ifp, struct mbuf *m)
3016 {
3017 	struct mbuf *copym;
3018 	struct ip6_hdr *ip6;
3019 
3020 	copym = m_copym(m, 0, M_COPYALL, M_NOWAIT);
3021 	if (copym == NULL)
3022 		return;
3023 
3024 	/*
3025 	 * Make sure to deep-copy IPv6 header portion in case the data
3026 	 * is in an mbuf cluster, so that we can safely override the IPv6
3027 	 * header portion later.
3028 	 */
3029 	if (!M_WRITABLE(copym) ||
3030 	    copym->m_len < sizeof(struct ip6_hdr)) {
3031 		copym = m_pullup(copym, sizeof(struct ip6_hdr));
3032 		if (copym == NULL)
3033 			return;
3034 	}
3035 	ip6 = mtod(copym, struct ip6_hdr *);
3036 	/*
3037 	 * clear embedded scope identifiers if necessary.
3038 	 * in6_clearscope will touch the addresses only when necessary.
3039 	 */
3040 	in6_clearscope(&ip6->ip6_src);
3041 	in6_clearscope(&ip6->ip6_dst);
3042 	if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
3043 		copym->m_pkthdr.csum_flags |= CSUM_DATA_VALID_IPV6 |
3044 		    CSUM_PSEUDO_HDR;
3045 		copym->m_pkthdr.csum_data = 0xffff;
3046 	}
3047 	if_simloop(ifp, copym, AF_INET6, 0);
3048 }
3049 
3050 /*
3051  * Chop IPv6 header off from the payload.
3052  */
3053 static int
3054 ip6_splithdr(struct mbuf *m, struct ip6_exthdrs *exthdrs)
3055 {
3056 	struct mbuf *mh;
3057 	struct ip6_hdr *ip6;
3058 
3059 	ip6 = mtod(m, struct ip6_hdr *);
3060 	if (m->m_len > sizeof(*ip6)) {
3061 		mh = m_gethdr(M_NOWAIT, MT_DATA);
3062 		if (mh == NULL) {
3063 			m_freem(m);
3064 			return ENOBUFS;
3065 		}
3066 		m_move_pkthdr(mh, m);
3067 		M_ALIGN(mh, sizeof(*ip6));
3068 		m->m_len -= sizeof(*ip6);
3069 		m->m_data += sizeof(*ip6);
3070 		mh->m_next = m;
3071 		m = mh;
3072 		m->m_len = sizeof(*ip6);
3073 		bcopy((caddr_t)ip6, mtod(m, caddr_t), sizeof(*ip6));
3074 	}
3075 	exthdrs->ip6e_ip6 = m;
3076 	return 0;
3077 }
3078 
3079 /*
3080  * Compute IPv6 extension header length.
3081  */
3082 int
3083 ip6_optlen(struct inpcb *in6p)
3084 {
3085 	int len;
3086 
3087 	if (!in6p->in6p_outputopts)
3088 		return 0;
3089 
3090 	len = 0;
3091 #define elen(x) \
3092     (((struct ip6_ext *)(x)) ? (((struct ip6_ext *)(x))->ip6e_len + 1) << 3 : 0)
3093 
3094 	len += elen(in6p->in6p_outputopts->ip6po_hbh);
3095 	if (in6p->in6p_outputopts->ip6po_rthdr)
3096 		/* dest1 is valid with rthdr only */
3097 		len += elen(in6p->in6p_outputopts->ip6po_dest1);
3098 	len += elen(in6p->in6p_outputopts->ip6po_rthdr);
3099 	len += elen(in6p->in6p_outputopts->ip6po_dest2);
3100 	return len;
3101 #undef elen
3102 }
3103