xref: /freebsd/sys/netinet6/ip6_output.c (revision 243e928310d073338c5ec089f0dce238a80b9866)
1 /*-
2  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the project nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  *	$KAME: ip6_output.c,v 1.279 2002/01/26 06:12:30 jinmei Exp $
30  */
31 
32 /*-
33  * Copyright (c) 1982, 1986, 1988, 1990, 1993
34  *	The Regents of the University of California.  All rights reserved.
35  *
36  * Redistribution and use in source and binary forms, with or without
37  * modification, are permitted provided that the following conditions
38  * are met:
39  * 1. Redistributions of source code must retain the above copyright
40  *    notice, this list of conditions and the following disclaimer.
41  * 2. Redistributions in binary form must reproduce the above copyright
42  *    notice, this list of conditions and the following disclaimer in the
43  *    documentation and/or other materials provided with the distribution.
44  * 4. Neither the name of the University nor the names of its contributors
45  *    may be used to endorse or promote products derived from this software
46  *    without specific prior written permission.
47  *
48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58  * SUCH DAMAGE.
59  *
60  *	@(#)ip_output.c	8.3 (Berkeley) 1/21/94
61  */
62 
63 #include <sys/cdefs.h>
64 __FBSDID("$FreeBSD$");
65 
66 #include "opt_inet.h"
67 #include "opt_inet6.h"
68 #include "opt_ipfw.h"
69 #include "opt_ipsec.h"
70 #include "opt_sctp.h"
71 #include "opt_route.h"
72 #include "opt_rss.h"
73 
74 #include <sys/param.h>
75 #include <sys/kernel.h>
76 #include <sys/malloc.h>
77 #include <sys/mbuf.h>
78 #include <sys/errno.h>
79 #include <sys/priv.h>
80 #include <sys/proc.h>
81 #include <sys/protosw.h>
82 #include <sys/socket.h>
83 #include <sys/socketvar.h>
84 #include <sys/syslog.h>
85 #include <sys/ucred.h>
86 
87 #include <machine/in_cksum.h>
88 
89 #include <net/if.h>
90 #include <net/if_var.h>
91 #include <net/netisr.h>
92 #include <net/route.h>
93 #include <net/pfil.h>
94 #include <net/rss_config.h>
95 #include <net/vnet.h>
96 
97 #include <netinet/in.h>
98 #include <netinet/in_var.h>
99 #include <netinet/ip_var.h>
100 #include <netinet6/in6_fib.h>
101 #include <netinet6/in6_var.h>
102 #include <netinet/ip6.h>
103 #include <netinet/icmp6.h>
104 #include <netinet6/ip6_var.h>
105 #include <netinet/in_pcb.h>
106 #include <netinet/tcp_var.h>
107 #include <netinet6/nd6.h>
108 #include <netinet6/in6_rss.h>
109 
110 #ifdef IPSEC
111 #include <netipsec/ipsec.h>
112 #include <netipsec/ipsec6.h>
113 #include <netipsec/key.h>
114 #include <netinet6/ip6_ipsec.h>
115 #endif /* IPSEC */
116 #ifdef SCTP
117 #include <netinet/sctp.h>
118 #include <netinet/sctp_crc32.h>
119 #endif
120 
121 #include <netinet6/ip6protosw.h>
122 #include <netinet6/scope6_var.h>
123 
124 #ifdef FLOWTABLE
125 #include <net/flowtable.h>
126 #endif
127 
128 extern int in6_mcast_loop;
129 
130 struct ip6_exthdrs {
131 	struct mbuf *ip6e_ip6;
132 	struct mbuf *ip6e_hbh;
133 	struct mbuf *ip6e_dest1;
134 	struct mbuf *ip6e_rthdr;
135 	struct mbuf *ip6e_dest2;
136 };
137 
138 static MALLOC_DEFINE(M_IP6OPT, "ip6opt", "IPv6 options");
139 
140 static int ip6_pcbopt(int, u_char *, int, struct ip6_pktopts **,
141 			   struct ucred *, int);
142 static int ip6_pcbopts(struct ip6_pktopts **, struct mbuf *,
143 	struct socket *, struct sockopt *);
144 static int ip6_getpcbopt(struct ip6_pktopts *, int, struct sockopt *);
145 static int ip6_setpktopt(int, u_char *, int, struct ip6_pktopts *,
146 	struct ucred *, int, int, int);
147 
148 static int ip6_copyexthdr(struct mbuf **, caddr_t, int);
149 static int ip6_insertfraghdr(struct mbuf *, struct mbuf *, int,
150 	struct ip6_frag **);
151 static int ip6_insert_jumboopt(struct ip6_exthdrs *, u_int32_t);
152 static int ip6_splithdr(struct mbuf *, struct ip6_exthdrs *);
153 static int ip6_getpmtu(struct route_in6 *, int,
154 	struct ifnet *, const struct in6_addr *, u_long *, int *, u_int);
155 static int ip6_calcmtu(struct ifnet *, const struct in6_addr *, u_long,
156 	u_long *, int *);
157 static int ip6_getpmtu_ctl(u_int, const struct in6_addr *, u_long *);
158 static int copypktopts(struct ip6_pktopts *, struct ip6_pktopts *, int);
159 
160 
161 /*
162  * Make an extension header from option data.  hp is the source, and
163  * mp is the destination.
164  */
165 #define MAKE_EXTHDR(hp, mp)						\
166     do {								\
167 	if (hp) {							\
168 		struct ip6_ext *eh = (struct ip6_ext *)(hp);		\
169 		error = ip6_copyexthdr((mp), (caddr_t)(hp),		\
170 		    ((eh)->ip6e_len + 1) << 3);				\
171 		if (error)						\
172 			goto freehdrs;					\
173 	}								\
174     } while (/*CONSTCOND*/ 0)
175 
176 /*
177  * Form a chain of extension headers.
178  * m is the extension header mbuf
179  * mp is the previous mbuf in the chain
180  * p is the next header
181  * i is the type of option.
182  */
183 #define MAKE_CHAIN(m, mp, p, i)\
184     do {\
185 	if (m) {\
186 		if (!hdrsplit) \
187 			panic("assumption failed: hdr not split"); \
188 		*mtod((m), u_char *) = *(p);\
189 		*(p) = (i);\
190 		p = mtod((m), u_char *);\
191 		(m)->m_next = (mp)->m_next;\
192 		(mp)->m_next = (m);\
193 		(mp) = (m);\
194 	}\
195     } while (/*CONSTCOND*/ 0)
196 
197 void
198 in6_delayed_cksum(struct mbuf *m, uint32_t plen, u_short offset)
199 {
200 	u_short csum;
201 
202 	csum = in_cksum_skip(m, offset + plen, offset);
203 	if (m->m_pkthdr.csum_flags & CSUM_UDP_IPV6 && csum == 0)
204 		csum = 0xffff;
205 	offset += m->m_pkthdr.csum_data;	/* checksum offset */
206 
207 	if (offset + sizeof(u_short) > m->m_len) {
208 		printf("%s: delayed m_pullup, m->len: %d plen %u off %u "
209 		    "csum_flags=%b\n", __func__, m->m_len, plen, offset,
210 		    (int)m->m_pkthdr.csum_flags, CSUM_BITS);
211 		/*
212 		 * XXX this should not happen, but if it does, the correct
213 		 * behavior may be to insert the checksum in the appropriate
214 		 * next mbuf in the chain.
215 		 */
216 		return;
217 	}
218 	*(u_short *)(m->m_data + offset) = csum;
219 }
220 
221 int
222 ip6_fragment(struct ifnet *ifp, struct mbuf *m0, int hlen, u_char nextproto,
223     int mtu, uint32_t id)
224 {
225 	struct mbuf *m, **mnext, *m_frgpart;
226 	struct ip6_hdr *ip6, *mhip6;
227 	struct ip6_frag *ip6f;
228 	int off;
229 	int error;
230 	int tlen = m0->m_pkthdr.len;
231 
232 	m = m0;
233 	ip6 = mtod(m, struct ip6_hdr *);
234 	mnext = &m->m_nextpkt;
235 
236 	for (off = hlen; off < tlen; off += mtu) {
237 		m = m_gethdr(M_NOWAIT, MT_DATA);
238 		if (!m) {
239 			IP6STAT_INC(ip6s_odropped);
240 			return (ENOBUFS);
241 		}
242 		m->m_flags = m0->m_flags & M_COPYFLAGS;
243 		*mnext = m;
244 		mnext = &m->m_nextpkt;
245 		m->m_data += max_linkhdr;
246 		mhip6 = mtod(m, struct ip6_hdr *);
247 		*mhip6 = *ip6;
248 		m->m_len = sizeof(*mhip6);
249 		error = ip6_insertfraghdr(m0, m, hlen, &ip6f);
250 		if (error) {
251 			IP6STAT_INC(ip6s_odropped);
252 			return (error);
253 		}
254 		ip6f->ip6f_offlg = htons((u_short)((off - hlen) & ~7));
255 		if (off + mtu >= tlen)
256 			mtu = tlen - off;
257 		else
258 			ip6f->ip6f_offlg |= IP6F_MORE_FRAG;
259 		mhip6->ip6_plen = htons((u_short)(mtu + hlen +
260 		    sizeof(*ip6f) - sizeof(struct ip6_hdr)));
261 		if ((m_frgpart = m_copy(m0, off, mtu)) == NULL) {
262 			IP6STAT_INC(ip6s_odropped);
263 			return (ENOBUFS);
264 		}
265 		m_cat(m, m_frgpart);
266 		m->m_pkthdr.len = mtu + hlen + sizeof(*ip6f);
267 		m->m_pkthdr.fibnum = m0->m_pkthdr.fibnum;
268 		m->m_pkthdr.rcvif = NULL;
269 		ip6f->ip6f_reserved = 0;
270 		ip6f->ip6f_ident = id;
271 		ip6f->ip6f_nxt = nextproto;
272 		IP6STAT_INC(ip6s_ofragments);
273 		in6_ifstat_inc(ifp, ifs6_out_fragcreat);
274 	}
275 
276 	return (0);
277 }
278 
279 /*
280  * IP6 output. The packet in mbuf chain m contains a skeletal IP6
281  * header (with pri, len, nxt, hlim, src, dst).
282  * This function may modify ver and hlim only.
283  * The mbuf chain containing the packet will be freed.
284  * The mbuf opt, if present, will not be freed.
285  * If route_in6 ro is present and has ro_rt initialized, route lookup would be
286  * skipped and ro->ro_rt would be used. If ro is present but ro->ro_rt is NULL,
287  * then result of route lookup is stored in ro->ro_rt.
288  *
289  * type of "mtu": rt_mtu is u_long, ifnet.ifr_mtu is int, and
290  * nd_ifinfo.linkmtu is u_int32_t.  so we use u_long to hold largest one,
291  * which is rt_mtu.
292  *
293  * ifpp - XXX: just for statistics
294  */
295 /*
296  * XXX TODO: no flowid is assigned for outbound flows?
297  */
298 int
299 ip6_output(struct mbuf *m0, struct ip6_pktopts *opt,
300     struct route_in6 *ro, int flags, struct ip6_moptions *im6o,
301     struct ifnet **ifpp, struct inpcb *inp)
302 {
303 	struct ip6_hdr *ip6;
304 	struct ifnet *ifp, *origifp;
305 	struct mbuf *m = m0;
306 	struct mbuf *mprev = NULL;
307 	int hlen, tlen, len;
308 	struct route_in6 ip6route;
309 	struct rtentry *rt = NULL;
310 	struct sockaddr_in6 *dst, src_sa, dst_sa;
311 	struct in6_addr odst;
312 	int error = 0;
313 	struct in6_ifaddr *ia = NULL;
314 	u_long mtu;
315 	int alwaysfrag, dontfrag;
316 	u_int32_t optlen = 0, plen = 0, unfragpartlen = 0;
317 	struct ip6_exthdrs exthdrs;
318 	struct in6_addr src0, dst0;
319 	u_int32_t zone;
320 	struct route_in6 *ro_pmtu = NULL;
321 	int hdrsplit = 0;
322 	int sw_csum, tso;
323 	int needfiblookup;
324 	uint32_t fibnum;
325 	struct m_tag *fwd_tag = NULL;
326 	uint32_t id;
327 
328 	if (inp != NULL) {
329 		M_SETFIB(m, inp->inp_inc.inc_fibnum);
330 		if ((flags & IP_NODEFAULTFLOWID) == 0) {
331 			/* unconditionally set flowid */
332 			m->m_pkthdr.flowid = inp->inp_flowid;
333 			M_HASHTYPE_SET(m, inp->inp_flowtype);
334 		}
335 	}
336 
337 	bzero(&exthdrs, sizeof(exthdrs));
338 	if (opt) {
339 		/* Hop-by-Hop options header */
340 		MAKE_EXTHDR(opt->ip6po_hbh, &exthdrs.ip6e_hbh);
341 		/* Destination options header(1st part) */
342 		if (opt->ip6po_rthdr) {
343 			/*
344 			 * Destination options header(1st part)
345 			 * This only makes sense with a routing header.
346 			 * See Section 9.2 of RFC 3542.
347 			 * Disabling this part just for MIP6 convenience is
348 			 * a bad idea.  We need to think carefully about a
349 			 * way to make the advanced API coexist with MIP6
350 			 * options, which might automatically be inserted in
351 			 * the kernel.
352 			 */
353 			MAKE_EXTHDR(opt->ip6po_dest1, &exthdrs.ip6e_dest1);
354 		}
355 		/* Routing header */
356 		MAKE_EXTHDR(opt->ip6po_rthdr, &exthdrs.ip6e_rthdr);
357 		/* Destination options header(2nd part) */
358 		MAKE_EXTHDR(opt->ip6po_dest2, &exthdrs.ip6e_dest2);
359 	}
360 
361 #ifdef IPSEC
362 	/*
363 	 * IPSec checking which handles several cases.
364 	 * FAST IPSEC: We re-injected the packet.
365 	 * XXX: need scope argument.
366 	 */
367 	switch(ip6_ipsec_output(&m, inp, &error))
368 	{
369 	case 1:                 /* Bad packet */
370 		goto freehdrs;
371 	case -1:                /* IPSec done */
372 		goto done;
373 	case 0:                 /* No IPSec */
374 	default:
375 		break;
376 	}
377 #endif /* IPSEC */
378 
379 	/*
380 	 * Calculate the total length of the extension header chain.
381 	 * Keep the length of the unfragmentable part for fragmentation.
382 	 */
383 	optlen = 0;
384 	if (exthdrs.ip6e_hbh)
385 		optlen += exthdrs.ip6e_hbh->m_len;
386 	if (exthdrs.ip6e_dest1)
387 		optlen += exthdrs.ip6e_dest1->m_len;
388 	if (exthdrs.ip6e_rthdr)
389 		optlen += exthdrs.ip6e_rthdr->m_len;
390 	unfragpartlen = optlen + sizeof(struct ip6_hdr);
391 
392 	/* NOTE: we don't add AH/ESP length here (done in ip6_ipsec_output) */
393 	if (exthdrs.ip6e_dest2)
394 		optlen += exthdrs.ip6e_dest2->m_len;
395 
396 	/*
397 	 * If there is at least one extension header,
398 	 * separate IP6 header from the payload.
399 	 */
400 	if (optlen && !hdrsplit) {
401 		if ((error = ip6_splithdr(m, &exthdrs)) != 0) {
402 			m = NULL;
403 			goto freehdrs;
404 		}
405 		m = exthdrs.ip6e_ip6;
406 		hdrsplit++;
407 	}
408 
409 	ip6 = mtod(m, struct ip6_hdr *);
410 
411 	/* adjust mbuf packet header length */
412 	m->m_pkthdr.len += optlen;
413 	plen = m->m_pkthdr.len - sizeof(*ip6);
414 
415 	/* If this is a jumbo payload, insert a jumbo payload option. */
416 	if (plen > IPV6_MAXPACKET) {
417 		if (!hdrsplit) {
418 			if ((error = ip6_splithdr(m, &exthdrs)) != 0) {
419 				m = NULL;
420 				goto freehdrs;
421 			}
422 			m = exthdrs.ip6e_ip6;
423 			hdrsplit++;
424 		}
425 		/* adjust pointer */
426 		ip6 = mtod(m, struct ip6_hdr *);
427 		if ((error = ip6_insert_jumboopt(&exthdrs, plen)) != 0)
428 			goto freehdrs;
429 		ip6->ip6_plen = 0;
430 	} else
431 		ip6->ip6_plen = htons(plen);
432 
433 	/*
434 	 * Concatenate headers and fill in next header fields.
435 	 * Here we have, on "m"
436 	 *	IPv6 payload
437 	 * and we insert headers accordingly.  Finally, we should be getting:
438 	 *	IPv6 hbh dest1 rthdr ah* [esp* dest2 payload]
439 	 *
440 	 * during the header composing process, "m" points to IPv6 header.
441 	 * "mprev" points to an extension header prior to esp.
442 	 */
443 	u_char *nexthdrp = &ip6->ip6_nxt;
444 	mprev = m;
445 
446 	/*
447 	 * we treat dest2 specially.  this makes IPsec processing
448 	 * much easier.  the goal here is to make mprev point the
449 	 * mbuf prior to dest2.
450 	 *
451 	 * result: IPv6 dest2 payload
452 	 * m and mprev will point to IPv6 header.
453 	 */
454 	if (exthdrs.ip6e_dest2) {
455 		if (!hdrsplit)
456 			panic("assumption failed: hdr not split");
457 		exthdrs.ip6e_dest2->m_next = m->m_next;
458 		m->m_next = exthdrs.ip6e_dest2;
459 		*mtod(exthdrs.ip6e_dest2, u_char *) = ip6->ip6_nxt;
460 		ip6->ip6_nxt = IPPROTO_DSTOPTS;
461 	}
462 
463 	/*
464 	 * result: IPv6 hbh dest1 rthdr dest2 payload
465 	 * m will point to IPv6 header.  mprev will point to the
466 	 * extension header prior to dest2 (rthdr in the above case).
467 	 */
468 	MAKE_CHAIN(exthdrs.ip6e_hbh, mprev, nexthdrp, IPPROTO_HOPOPTS);
469 	MAKE_CHAIN(exthdrs.ip6e_dest1, mprev, nexthdrp,
470 		   IPPROTO_DSTOPTS);
471 	MAKE_CHAIN(exthdrs.ip6e_rthdr, mprev, nexthdrp,
472 		   IPPROTO_ROUTING);
473 
474 	/*
475 	 * If there is a routing header, discard the packet.
476 	 */
477 	if (exthdrs.ip6e_rthdr) {
478 		 error = EINVAL;
479 		 goto bad;
480 	}
481 
482 	/* Source address validation */
483 	if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) &&
484 	    (flags & IPV6_UNSPECSRC) == 0) {
485 		error = EOPNOTSUPP;
486 		IP6STAT_INC(ip6s_badscope);
487 		goto bad;
488 	}
489 	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_src)) {
490 		error = EOPNOTSUPP;
491 		IP6STAT_INC(ip6s_badscope);
492 		goto bad;
493 	}
494 
495 	IP6STAT_INC(ip6s_localout);
496 
497 	/*
498 	 * Route packet.
499 	 */
500 	if (ro == NULL) {
501 		ro = &ip6route;
502 		bzero((caddr_t)ro, sizeof(*ro));
503 	}
504 	ro_pmtu = ro;
505 	if (opt && opt->ip6po_rthdr)
506 		ro = &opt->ip6po_route;
507 	dst = (struct sockaddr_in6 *)&ro->ro_dst;
508 #ifdef FLOWTABLE
509 	if (ro->ro_rt == NULL)
510 		(void )flowtable_lookup(AF_INET6, m, (struct route *)ro);
511 #endif
512 	fibnum = (inp != NULL) ? inp->inp_inc.inc_fibnum : M_GETFIB(m);
513 again:
514 	/*
515 	 * if specified, try to fill in the traffic class field.
516 	 * do not override if a non-zero value is already set.
517 	 * we check the diffserv field and the ecn field separately.
518 	 */
519 	if (opt && opt->ip6po_tclass >= 0) {
520 		int mask = 0;
521 
522 		if ((ip6->ip6_flow & htonl(0xfc << 20)) == 0)
523 			mask |= 0xfc;
524 		if ((ip6->ip6_flow & htonl(0x03 << 20)) == 0)
525 			mask |= 0x03;
526 		if (mask != 0)
527 			ip6->ip6_flow |= htonl((opt->ip6po_tclass & mask) << 20);
528 	}
529 
530 	/* fill in or override the hop limit field, if necessary. */
531 	if (opt && opt->ip6po_hlim != -1)
532 		ip6->ip6_hlim = opt->ip6po_hlim & 0xff;
533 	else if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
534 		if (im6o != NULL)
535 			ip6->ip6_hlim = im6o->im6o_multicast_hlim;
536 		else
537 			ip6->ip6_hlim = V_ip6_defmcasthlim;
538 	}
539 	/*
540 	 * Validate route against routing table additions;
541 	 * a better/more specific route might have been added.
542 	 * Make sure address family is set in route.
543 	 */
544 	if (inp) {
545 		ro->ro_dst.sin6_family = AF_INET6;
546 		RT_VALIDATE((struct route *)ro, &inp->inp_rt_cookie, fibnum);
547 	}
548 	if (ro->ro_rt && fwd_tag == NULL && (ro->ro_rt->rt_flags & RTF_UP) &&
549 	    ro->ro_dst.sin6_family == AF_INET6 &&
550 	    IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, &ip6->ip6_dst)) {
551 		rt = ro->ro_rt;
552 		ifp = ro->ro_rt->rt_ifp;
553 	} else {
554 		if (fwd_tag == NULL) {
555 			bzero(&dst_sa, sizeof(dst_sa));
556 			dst_sa.sin6_family = AF_INET6;
557 			dst_sa.sin6_len = sizeof(dst_sa);
558 			dst_sa.sin6_addr = ip6->ip6_dst;
559 		}
560 		error = in6_selectroute_fib(&dst_sa, opt, im6o, ro, &ifp,
561 		    &rt, fibnum);
562 		if (error != 0) {
563 			if (ifp != NULL)
564 				in6_ifstat_inc(ifp, ifs6_out_discard);
565 			goto bad;
566 		}
567 	}
568 	if (rt == NULL) {
569 		/*
570 		 * If in6_selectroute() does not return a route entry,
571 		 * dst may not have been updated.
572 		 */
573 		*dst = dst_sa;	/* XXX */
574 	}
575 
576 	/*
577 	 * then rt (for unicast) and ifp must be non-NULL valid values.
578 	 */
579 	if ((flags & IPV6_FORWARDING) == 0) {
580 		/* XXX: the FORWARDING flag can be set for mrouting. */
581 		in6_ifstat_inc(ifp, ifs6_out_request);
582 	}
583 	if (rt != NULL) {
584 		ia = (struct in6_ifaddr *)(rt->rt_ifa);
585 		counter_u64_add(rt->rt_pksent, 1);
586 	}
587 
588 
589 	/*
590 	 * The outgoing interface must be in the zone of source and
591 	 * destination addresses.
592 	 */
593 	origifp = ifp;
594 
595 	src0 = ip6->ip6_src;
596 	if (in6_setscope(&src0, origifp, &zone))
597 		goto badscope;
598 	bzero(&src_sa, sizeof(src_sa));
599 	src_sa.sin6_family = AF_INET6;
600 	src_sa.sin6_len = sizeof(src_sa);
601 	src_sa.sin6_addr = ip6->ip6_src;
602 	if (sa6_recoverscope(&src_sa) || zone != src_sa.sin6_scope_id)
603 		goto badscope;
604 
605 	dst0 = ip6->ip6_dst;
606 	if (in6_setscope(&dst0, origifp, &zone))
607 		goto badscope;
608 	/* re-initialize to be sure */
609 	bzero(&dst_sa, sizeof(dst_sa));
610 	dst_sa.sin6_family = AF_INET6;
611 	dst_sa.sin6_len = sizeof(dst_sa);
612 	dst_sa.sin6_addr = ip6->ip6_dst;
613 	if (sa6_recoverscope(&dst_sa) || zone != dst_sa.sin6_scope_id) {
614 		goto badscope;
615 	}
616 
617 	/* We should use ia_ifp to support the case of
618 	 * sending packets to an address of our own.
619 	 */
620 	if (ia != NULL && ia->ia_ifp)
621 		ifp = ia->ia_ifp;
622 
623 	/* scope check is done. */
624 	goto routefound;
625 
626   badscope:
627 	IP6STAT_INC(ip6s_badscope);
628 	in6_ifstat_inc(origifp, ifs6_out_discard);
629 	if (error == 0)
630 		error = EHOSTUNREACH; /* XXX */
631 	goto bad;
632 
633   routefound:
634 	if (rt && !IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
635 		if (opt && opt->ip6po_nextroute.ro_rt) {
636 			/*
637 			 * The nexthop is explicitly specified by the
638 			 * application.  We assume the next hop is an IPv6
639 			 * address.
640 			 */
641 			dst = (struct sockaddr_in6 *)opt->ip6po_nexthop;
642 		}
643 		else if ((rt->rt_flags & RTF_GATEWAY))
644 			dst = (struct sockaddr_in6 *)rt->rt_gateway;
645 	}
646 
647 	if (!IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
648 		m->m_flags &= ~(M_BCAST | M_MCAST); /* just in case */
649 	} else {
650 		m->m_flags = (m->m_flags & ~M_BCAST) | M_MCAST;
651 		in6_ifstat_inc(ifp, ifs6_out_mcast);
652 		/*
653 		 * Confirm that the outgoing interface supports multicast.
654 		 */
655 		if (!(ifp->if_flags & IFF_MULTICAST)) {
656 			IP6STAT_INC(ip6s_noroute);
657 			in6_ifstat_inc(ifp, ifs6_out_discard);
658 			error = ENETUNREACH;
659 			goto bad;
660 		}
661 		if ((im6o == NULL && in6_mcast_loop) ||
662 		    (im6o && im6o->im6o_multicast_loop)) {
663 			/*
664 			 * Loop back multicast datagram if not expressly
665 			 * forbidden to do so, even if we have not joined
666 			 * the address; protocols will filter it later,
667 			 * thus deferring a hash lookup and lock acquisition
668 			 * at the expense of an m_copym().
669 			 */
670 			ip6_mloopback(ifp, m);
671 		} else {
672 			/*
673 			 * If we are acting as a multicast router, perform
674 			 * multicast forwarding as if the packet had just
675 			 * arrived on the interface to which we are about
676 			 * to send.  The multicast forwarding function
677 			 * recursively calls this function, using the
678 			 * IPV6_FORWARDING flag to prevent infinite recursion.
679 			 *
680 			 * Multicasts that are looped back by ip6_mloopback(),
681 			 * above, will be forwarded by the ip6_input() routine,
682 			 * if necessary.
683 			 */
684 			if (V_ip6_mrouter && (flags & IPV6_FORWARDING) == 0) {
685 				/*
686 				 * XXX: ip6_mforward expects that rcvif is NULL
687 				 * when it is called from the originating path.
688 				 * However, it may not always be the case.
689 				 */
690 				m->m_pkthdr.rcvif = NULL;
691 				if (ip6_mforward(ip6, ifp, m) != 0) {
692 					m_freem(m);
693 					goto done;
694 				}
695 			}
696 		}
697 		/*
698 		 * Multicasts with a hoplimit of zero may be looped back,
699 		 * above, but must not be transmitted on a network.
700 		 * Also, multicasts addressed to the loopback interface
701 		 * are not sent -- the above call to ip6_mloopback() will
702 		 * loop back a copy if this host actually belongs to the
703 		 * destination group on the loopback interface.
704 		 */
705 		if (ip6->ip6_hlim == 0 || (ifp->if_flags & IFF_LOOPBACK) ||
706 		    IN6_IS_ADDR_MC_INTFACELOCAL(&ip6->ip6_dst)) {
707 			m_freem(m);
708 			goto done;
709 		}
710 	}
711 
712 	/*
713 	 * Fill the outgoing inteface to tell the upper layer
714 	 * to increment per-interface statistics.
715 	 */
716 	if (ifpp)
717 		*ifpp = ifp;
718 
719 	/* Determine path MTU. */
720 	if ((error = ip6_getpmtu(ro_pmtu, ro != ro_pmtu, ifp, &ip6->ip6_dst,
721 	    &mtu, &alwaysfrag, fibnum)) != 0)
722 		goto bad;
723 
724 	/*
725 	 * The caller of this function may specify to use the minimum MTU
726 	 * in some cases.
727 	 * An advanced API option (IPV6_USE_MIN_MTU) can also override MTU
728 	 * setting.  The logic is a bit complicated; by default, unicast
729 	 * packets will follow path MTU while multicast packets will be sent at
730 	 * the minimum MTU.  If IP6PO_MINMTU_ALL is specified, all packets
731 	 * including unicast ones will be sent at the minimum MTU.  Multicast
732 	 * packets will always be sent at the minimum MTU unless
733 	 * IP6PO_MINMTU_DISABLE is explicitly specified.
734 	 * See RFC 3542 for more details.
735 	 */
736 	if (mtu > IPV6_MMTU) {
737 		if ((flags & IPV6_MINMTU))
738 			mtu = IPV6_MMTU;
739 		else if (opt && opt->ip6po_minmtu == IP6PO_MINMTU_ALL)
740 			mtu = IPV6_MMTU;
741 		else if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) &&
742 			 (opt == NULL ||
743 			  opt->ip6po_minmtu != IP6PO_MINMTU_DISABLE)) {
744 			mtu = IPV6_MMTU;
745 		}
746 	}
747 
748 	/*
749 	 * clear embedded scope identifiers if necessary.
750 	 * in6_clearscope will touch the addresses only when necessary.
751 	 */
752 	in6_clearscope(&ip6->ip6_src);
753 	in6_clearscope(&ip6->ip6_dst);
754 
755 	/*
756 	 * If the outgoing packet contains a hop-by-hop options header,
757 	 * it must be examined and processed even by the source node.
758 	 * (RFC 2460, section 4.)
759 	 */
760 	if (exthdrs.ip6e_hbh) {
761 		struct ip6_hbh *hbh = mtod(exthdrs.ip6e_hbh, struct ip6_hbh *);
762 		u_int32_t dummy; /* XXX unused */
763 		u_int32_t plen = 0; /* XXX: ip6_process will check the value */
764 
765 #ifdef DIAGNOSTIC
766 		if ((hbh->ip6h_len + 1) << 3 > exthdrs.ip6e_hbh->m_len)
767 			panic("ip6e_hbh is not contiguous");
768 #endif
769 		/*
770 		 *  XXX: if we have to send an ICMPv6 error to the sender,
771 		 *       we need the M_LOOP flag since icmp6_error() expects
772 		 *       the IPv6 and the hop-by-hop options header are
773 		 *       contiguous unless the flag is set.
774 		 */
775 		m->m_flags |= M_LOOP;
776 		m->m_pkthdr.rcvif = ifp;
777 		if (ip6_process_hopopts(m, (u_int8_t *)(hbh + 1),
778 		    ((hbh->ip6h_len + 1) << 3) - sizeof(struct ip6_hbh),
779 		    &dummy, &plen) < 0) {
780 			/* m was already freed at this point */
781 			error = EINVAL;/* better error? */
782 			goto done;
783 		}
784 		m->m_flags &= ~M_LOOP; /* XXX */
785 		m->m_pkthdr.rcvif = NULL;
786 	}
787 
788 	/* Jump over all PFIL processing if hooks are not active. */
789 	if (!PFIL_HOOKED(&V_inet6_pfil_hook))
790 		goto passout;
791 
792 	odst = ip6->ip6_dst;
793 	/* Run through list of hooks for output packets. */
794 	error = pfil_run_hooks(&V_inet6_pfil_hook, &m, ifp, PFIL_OUT, inp);
795 	if (error != 0 || m == NULL)
796 		goto done;
797 	/* adjust pointer */
798 	ip6 = mtod(m, struct ip6_hdr *);
799 
800 	needfiblookup = 0;
801 	/* See if destination IP address was changed by packet filter. */
802 	if (!IN6_ARE_ADDR_EQUAL(&odst, &ip6->ip6_dst)) {
803 		m->m_flags |= M_SKIP_FIREWALL;
804 		/* If destination is now ourself drop to ip6_input(). */
805 		if (in6_localip(&ip6->ip6_dst)) {
806 			m->m_flags |= M_FASTFWD_OURS;
807 			if (m->m_pkthdr.rcvif == NULL)
808 				m->m_pkthdr.rcvif = V_loif;
809 			if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
810 				m->m_pkthdr.csum_flags |=
811 				    CSUM_DATA_VALID_IPV6 | CSUM_PSEUDO_HDR;
812 				m->m_pkthdr.csum_data = 0xffff;
813 			}
814 #ifdef SCTP
815 			if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6)
816 				m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
817 #endif
818 			error = netisr_queue(NETISR_IPV6, m);
819 			goto done;
820 		} else {
821 			RO_RTFREE(ro);
822 			needfiblookup = 1; /* Redo the routing table lookup. */
823 		}
824 	}
825 	/* See if fib was changed by packet filter. */
826 	if (fibnum != M_GETFIB(m)) {
827 		m->m_flags |= M_SKIP_FIREWALL;
828 		fibnum = M_GETFIB(m);
829 		RO_RTFREE(ro);
830 		needfiblookup = 1;
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 		error = nd6_output_ifp(ifp, origifp, m, dst,
947 		    (struct route *)ro);
948 		goto done;
949 	}
950 
951 	/*
952 	 * try to fragment the packet.  case 1-b and 3
953 	 */
954 	if (mtu < IPV6_MMTU) {
955 		/* path MTU cannot be less than IPV6_MMTU */
956 		error = EMSGSIZE;
957 		in6_ifstat_inc(ifp, ifs6_out_fragfail);
958 		goto bad;
959 	} else if (ip6->ip6_plen == 0) {
960 		/* jumbo payload cannot be fragmented */
961 		error = EMSGSIZE;
962 		in6_ifstat_inc(ifp, ifs6_out_fragfail);
963 		goto bad;
964 	} else {
965 		u_char nextproto;
966 
967 		/*
968 		 * Too large for the destination or interface;
969 		 * fragment if possible.
970 		 * Must be able to put at least 8 bytes per fragment.
971 		 */
972 		hlen = unfragpartlen;
973 		if (mtu > IPV6_MAXPACKET)
974 			mtu = IPV6_MAXPACKET;
975 
976 		len = (mtu - hlen - sizeof(struct ip6_frag)) & ~7;
977 		if (len < 8) {
978 			error = EMSGSIZE;
979 			in6_ifstat_inc(ifp, ifs6_out_fragfail);
980 			goto bad;
981 		}
982 
983 		/*
984 		 * If the interface will not calculate checksums on
985 		 * fragmented packets, then do it here.
986 		 * XXX-BZ handle the hw offloading case.  Need flags.
987 		 */
988 		if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
989 			in6_delayed_cksum(m, plen, hlen);
990 			m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA_IPV6;
991 		}
992 #ifdef SCTP
993 		if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6) {
994 			sctp_delayed_cksum(m, hlen);
995 			m->m_pkthdr.csum_flags &= ~CSUM_SCTP_IPV6;
996 		}
997 #endif
998 		/*
999 		 * Change the next header field of the last header in the
1000 		 * unfragmentable part.
1001 		 */
1002 		if (exthdrs.ip6e_rthdr) {
1003 			nextproto = *mtod(exthdrs.ip6e_rthdr, u_char *);
1004 			*mtod(exthdrs.ip6e_rthdr, u_char *) = IPPROTO_FRAGMENT;
1005 		} else if (exthdrs.ip6e_dest1) {
1006 			nextproto = *mtod(exthdrs.ip6e_dest1, u_char *);
1007 			*mtod(exthdrs.ip6e_dest1, u_char *) = IPPROTO_FRAGMENT;
1008 		} else if (exthdrs.ip6e_hbh) {
1009 			nextproto = *mtod(exthdrs.ip6e_hbh, u_char *);
1010 			*mtod(exthdrs.ip6e_hbh, u_char *) = IPPROTO_FRAGMENT;
1011 		} else {
1012 			nextproto = ip6->ip6_nxt;
1013 			ip6->ip6_nxt = IPPROTO_FRAGMENT;
1014 		}
1015 
1016 		/*
1017 		 * Loop through length of segment after first fragment,
1018 		 * make new header and copy data of each part and link onto
1019 		 * chain.
1020 		 */
1021 		m0 = m;
1022 		id = htonl(ip6_randomid());
1023 		if ((error = ip6_fragment(ifp, m, hlen, nextproto, len, id)))
1024 			goto sendorfree;
1025 
1026 		in6_ifstat_inc(ifp, ifs6_out_fragok);
1027 	}
1028 
1029 	/*
1030 	 * Remove leading garbages.
1031 	 */
1032 sendorfree:
1033 	m = m0->m_nextpkt;
1034 	m0->m_nextpkt = 0;
1035 	m_freem(m0);
1036 	for (m0 = m; m; m = m0) {
1037 		m0 = m->m_nextpkt;
1038 		m->m_nextpkt = 0;
1039 		if (error == 0) {
1040 			/* Record statistics for this interface address. */
1041 			if (ia) {
1042 				counter_u64_add(ia->ia_ifa.ifa_opackets, 1);
1043 				counter_u64_add(ia->ia_ifa.ifa_obytes,
1044 				    m->m_pkthdr.len);
1045 			}
1046 			error = nd6_output_ifp(ifp, origifp, m, dst,
1047 			    (struct route *)ro);
1048 		} else
1049 			m_freem(m);
1050 	}
1051 
1052 	if (error == 0)
1053 		IP6STAT_INC(ip6s_fragmented);
1054 
1055 done:
1056 	if (ro == &ip6route)
1057 		RO_RTFREE(ro);
1058 	return (error);
1059 
1060 freehdrs:
1061 	m_freem(exthdrs.ip6e_hbh);	/* m_freem will check if mbuf is 0 */
1062 	m_freem(exthdrs.ip6e_dest1);
1063 	m_freem(exthdrs.ip6e_rthdr);
1064 	m_freem(exthdrs.ip6e_dest2);
1065 	/* FALLTHROUGH */
1066 bad:
1067 	if (m)
1068 		m_freem(m);
1069 	goto done;
1070 }
1071 
1072 static int
1073 ip6_copyexthdr(struct mbuf **mp, caddr_t hdr, int hlen)
1074 {
1075 	struct mbuf *m;
1076 
1077 	if (hlen > MCLBYTES)
1078 		return (ENOBUFS); /* XXX */
1079 
1080 	if (hlen > MLEN)
1081 		m = m_getcl(M_NOWAIT, MT_DATA, 0);
1082 	else
1083 		m = m_get(M_NOWAIT, MT_DATA);
1084 	if (m == NULL)
1085 		return (ENOBUFS);
1086 	m->m_len = hlen;
1087 	if (hdr)
1088 		bcopy(hdr, mtod(m, caddr_t), hlen);
1089 
1090 	*mp = m;
1091 	return (0);
1092 }
1093 
1094 /*
1095  * Insert jumbo payload option.
1096  */
1097 static int
1098 ip6_insert_jumboopt(struct ip6_exthdrs *exthdrs, u_int32_t plen)
1099 {
1100 	struct mbuf *mopt;
1101 	u_char *optbuf;
1102 	u_int32_t v;
1103 
1104 #define JUMBOOPTLEN	8	/* length of jumbo payload option and padding */
1105 
1106 	/*
1107 	 * If there is no hop-by-hop options header, allocate new one.
1108 	 * If there is one but it doesn't have enough space to store the
1109 	 * jumbo payload option, allocate a cluster to store the whole options.
1110 	 * Otherwise, use it to store the options.
1111 	 */
1112 	if (exthdrs->ip6e_hbh == NULL) {
1113 		mopt = m_get(M_NOWAIT, MT_DATA);
1114 		if (mopt == NULL)
1115 			return (ENOBUFS);
1116 		mopt->m_len = JUMBOOPTLEN;
1117 		optbuf = mtod(mopt, u_char *);
1118 		optbuf[1] = 0;	/* = ((JUMBOOPTLEN) >> 3) - 1 */
1119 		exthdrs->ip6e_hbh = mopt;
1120 	} else {
1121 		struct ip6_hbh *hbh;
1122 
1123 		mopt = exthdrs->ip6e_hbh;
1124 		if (M_TRAILINGSPACE(mopt) < JUMBOOPTLEN) {
1125 			/*
1126 			 * XXX assumption:
1127 			 * - exthdrs->ip6e_hbh is not referenced from places
1128 			 *   other than exthdrs.
1129 			 * - exthdrs->ip6e_hbh is not an mbuf chain.
1130 			 */
1131 			int oldoptlen = mopt->m_len;
1132 			struct mbuf *n;
1133 
1134 			/*
1135 			 * XXX: give up if the whole (new) hbh header does
1136 			 * not fit even in an mbuf cluster.
1137 			 */
1138 			if (oldoptlen + JUMBOOPTLEN > MCLBYTES)
1139 				return (ENOBUFS);
1140 
1141 			/*
1142 			 * As a consequence, we must always prepare a cluster
1143 			 * at this point.
1144 			 */
1145 			n = m_getcl(M_NOWAIT, MT_DATA, 0);
1146 			if (n == NULL)
1147 				return (ENOBUFS);
1148 			n->m_len = oldoptlen + JUMBOOPTLEN;
1149 			bcopy(mtod(mopt, caddr_t), mtod(n, caddr_t),
1150 			    oldoptlen);
1151 			optbuf = mtod(n, caddr_t) + oldoptlen;
1152 			m_freem(mopt);
1153 			mopt = exthdrs->ip6e_hbh = n;
1154 		} else {
1155 			optbuf = mtod(mopt, u_char *) + mopt->m_len;
1156 			mopt->m_len += JUMBOOPTLEN;
1157 		}
1158 		optbuf[0] = IP6OPT_PADN;
1159 		optbuf[1] = 1;
1160 
1161 		/*
1162 		 * Adjust the header length according to the pad and
1163 		 * the jumbo payload option.
1164 		 */
1165 		hbh = mtod(mopt, struct ip6_hbh *);
1166 		hbh->ip6h_len += (JUMBOOPTLEN >> 3);
1167 	}
1168 
1169 	/* fill in the option. */
1170 	optbuf[2] = IP6OPT_JUMBO;
1171 	optbuf[3] = 4;
1172 	v = (u_int32_t)htonl(plen + JUMBOOPTLEN);
1173 	bcopy(&v, &optbuf[4], sizeof(u_int32_t));
1174 
1175 	/* finally, adjust the packet header length */
1176 	exthdrs->ip6e_ip6->m_pkthdr.len += JUMBOOPTLEN;
1177 
1178 	return (0);
1179 #undef JUMBOOPTLEN
1180 }
1181 
1182 /*
1183  * Insert fragment header and copy unfragmentable header portions.
1184  */
1185 static int
1186 ip6_insertfraghdr(struct mbuf *m0, struct mbuf *m, int hlen,
1187     struct ip6_frag **frghdrp)
1188 {
1189 	struct mbuf *n, *mlast;
1190 
1191 	if (hlen > sizeof(struct ip6_hdr)) {
1192 		n = m_copym(m0, sizeof(struct ip6_hdr),
1193 		    hlen - sizeof(struct ip6_hdr), M_NOWAIT);
1194 		if (n == NULL)
1195 			return (ENOBUFS);
1196 		m->m_next = n;
1197 	} else
1198 		n = m;
1199 
1200 	/* Search for the last mbuf of unfragmentable part. */
1201 	for (mlast = n; mlast->m_next; mlast = mlast->m_next)
1202 		;
1203 
1204 	if (M_WRITABLE(mlast) &&
1205 	    M_TRAILINGSPACE(mlast) >= sizeof(struct ip6_frag)) {
1206 		/* use the trailing space of the last mbuf for the fragment hdr */
1207 		*frghdrp = (struct ip6_frag *)(mtod(mlast, caddr_t) +
1208 		    mlast->m_len);
1209 		mlast->m_len += sizeof(struct ip6_frag);
1210 		m->m_pkthdr.len += sizeof(struct ip6_frag);
1211 	} else {
1212 		/* allocate a new mbuf for the fragment header */
1213 		struct mbuf *mfrg;
1214 
1215 		mfrg = m_get(M_NOWAIT, MT_DATA);
1216 		if (mfrg == NULL)
1217 			return (ENOBUFS);
1218 		mfrg->m_len = sizeof(struct ip6_frag);
1219 		*frghdrp = mtod(mfrg, struct ip6_frag *);
1220 		mlast->m_next = mfrg;
1221 	}
1222 
1223 	return (0);
1224 }
1225 
1226 /*
1227  * Calculates IPv6 path mtu for destination @dst.
1228  * Resulting MTU is stored in @mtup.
1229  *
1230  * Returns 0 on success.
1231  */
1232 static int
1233 ip6_getpmtu_ctl(u_int fibnum, const struct in6_addr *dst, u_long *mtup)
1234 {
1235 	struct nhop6_extended nh6;
1236 	struct in6_addr kdst;
1237 	uint32_t scopeid;
1238 	struct ifnet *ifp;
1239 	u_long mtu;
1240 	int error;
1241 
1242 	in6_splitscope(dst, &kdst, &scopeid);
1243 	if (fib6_lookup_nh_ext(fibnum, &kdst, scopeid, NHR_REF, 0, &nh6) != 0)
1244 		return (EHOSTUNREACH);
1245 
1246 	ifp = nh6.nh_ifp;
1247 	mtu = nh6.nh_mtu;
1248 
1249 	error = ip6_calcmtu(ifp, dst, mtu, mtup, NULL);
1250 	fib6_free_nh_ext(fibnum, &nh6);
1251 
1252 	return (error);
1253 }
1254 
1255 /*
1256  * Calculates IPv6 path MTU for @dst based on transmit @ifp,
1257  * and cached data in @ro_pmtu.
1258  * MTU from (successful) route lookup is saved (along with dst)
1259  * inside @ro_pmtu to avoid subsequent route lookups after packet
1260  * filter processing.
1261  *
1262  * Stores mtu and always-frag value into @mtup and @alwaysfragp.
1263  * Returns 0 on success.
1264  */
1265 static int
1266 ip6_getpmtu(struct route_in6 *ro_pmtu, int do_lookup,
1267     struct ifnet *ifp, const struct in6_addr *dst, u_long *mtup,
1268     int *alwaysfragp, u_int fibnum)
1269 {
1270 	struct nhop6_basic nh6;
1271 	struct in6_addr kdst;
1272 	uint32_t scopeid;
1273 	struct sockaddr_in6 *sa6_dst;
1274 	u_long mtu;
1275 
1276 	mtu = 0;
1277 	if (do_lookup) {
1278 
1279 		/*
1280 		 * Here ro_pmtu has final destination address, while
1281 		 * ro might represent immediate destination.
1282 		 * Use ro_pmtu destination since mtu might differ.
1283 		 */
1284 		sa6_dst = (struct sockaddr_in6 *)&ro_pmtu->ro_dst;
1285 		if (!IN6_ARE_ADDR_EQUAL(&sa6_dst->sin6_addr, dst))
1286 			ro_pmtu->ro_mtu = 0;
1287 
1288 		if (ro_pmtu->ro_mtu == 0) {
1289 			bzero(sa6_dst, sizeof(*sa6_dst));
1290 			sa6_dst->sin6_family = AF_INET6;
1291 			sa6_dst->sin6_len = sizeof(struct sockaddr_in6);
1292 			sa6_dst->sin6_addr = *dst;
1293 
1294 			in6_splitscope(dst, &kdst, &scopeid);
1295 			if (fib6_lookup_nh_basic(fibnum, &kdst, scopeid, 0, 0,
1296 			    &nh6) == 0)
1297 				ro_pmtu->ro_mtu = nh6.nh_mtu;
1298 		}
1299 
1300 		mtu = ro_pmtu->ro_mtu;
1301 	}
1302 
1303 	if (ro_pmtu->ro_rt)
1304 		mtu = ro_pmtu->ro_rt->rt_mtu;
1305 
1306 	return (ip6_calcmtu(ifp, dst, mtu, mtup, alwaysfragp));
1307 }
1308 
1309 /*
1310  * Calculate MTU based on transmit @ifp, route mtu @rt_mtu and
1311  * hostcache data for @dst.
1312  * Stores mtu and always-frag value into @mtup and @alwaysfragp.
1313  *
1314  * Returns 0 on success.
1315  */
1316 static int
1317 ip6_calcmtu(struct ifnet *ifp, const struct in6_addr *dst, u_long rt_mtu,
1318     u_long *mtup, int *alwaysfragp)
1319 {
1320 	u_long mtu = 0;
1321 	int alwaysfrag = 0;
1322 	int error = 0;
1323 
1324 	if (rt_mtu > 0) {
1325 		u_int32_t ifmtu;
1326 		struct in_conninfo inc;
1327 
1328 		bzero(&inc, sizeof(inc));
1329 		inc.inc_flags |= INC_ISIPV6;
1330 		inc.inc6_faddr = *dst;
1331 
1332 		ifmtu = IN6_LINKMTU(ifp);
1333 		mtu = tcp_hc_getmtu(&inc);
1334 		if (mtu)
1335 			mtu = min(mtu, rt_mtu);
1336 		else
1337 			mtu = rt_mtu;
1338 		if (mtu == 0)
1339 			mtu = ifmtu;
1340 		else if (mtu < IPV6_MMTU) {
1341 			/*
1342 			 * RFC2460 section 5, last paragraph:
1343 			 * if we record ICMPv6 too big message with
1344 			 * mtu < IPV6_MMTU, transmit packets sized IPV6_MMTU
1345 			 * or smaller, with framgent header attached.
1346 			 * (fragment header is needed regardless from the
1347 			 * packet size, for translators to identify packets)
1348 			 */
1349 			alwaysfrag = 1;
1350 			mtu = IPV6_MMTU;
1351 		}
1352 	} else if (ifp) {
1353 		mtu = IN6_LINKMTU(ifp);
1354 	} else
1355 		error = EHOSTUNREACH; /* XXX */
1356 
1357 	*mtup = mtu;
1358 	if (alwaysfragp)
1359 		*alwaysfragp = alwaysfrag;
1360 	return (error);
1361 }
1362 
1363 /*
1364  * IP6 socket option processing.
1365  */
1366 int
1367 ip6_ctloutput(struct socket *so, struct sockopt *sopt)
1368 {
1369 	int optdatalen, uproto;
1370 	void *optdata;
1371 	struct inpcb *in6p = sotoinpcb(so);
1372 	int error, optval;
1373 	int level, op, optname;
1374 	int optlen;
1375 	struct thread *td;
1376 #ifdef	RSS
1377 	uint32_t rss_bucket;
1378 	int retval;
1379 #endif
1380 
1381 	level = sopt->sopt_level;
1382 	op = sopt->sopt_dir;
1383 	optname = sopt->sopt_name;
1384 	optlen = sopt->sopt_valsize;
1385 	td = sopt->sopt_td;
1386 	error = 0;
1387 	optval = 0;
1388 	uproto = (int)so->so_proto->pr_protocol;
1389 
1390 	if (level != IPPROTO_IPV6) {
1391 		error = EINVAL;
1392 
1393 		if (sopt->sopt_level == SOL_SOCKET &&
1394 		    sopt->sopt_dir == SOPT_SET) {
1395 			switch (sopt->sopt_name) {
1396 			case SO_REUSEADDR:
1397 				INP_WLOCK(in6p);
1398 				if ((so->so_options & SO_REUSEADDR) != 0)
1399 					in6p->inp_flags2 |= INP_REUSEADDR;
1400 				else
1401 					in6p->inp_flags2 &= ~INP_REUSEADDR;
1402 				INP_WUNLOCK(in6p);
1403 				error = 0;
1404 				break;
1405 			case SO_REUSEPORT:
1406 				INP_WLOCK(in6p);
1407 				if ((so->so_options & SO_REUSEPORT) != 0)
1408 					in6p->inp_flags2 |= INP_REUSEPORT;
1409 				else
1410 					in6p->inp_flags2 &= ~INP_REUSEPORT;
1411 				INP_WUNLOCK(in6p);
1412 				error = 0;
1413 				break;
1414 			case SO_SETFIB:
1415 				INP_WLOCK(in6p);
1416 				in6p->inp_inc.inc_fibnum = so->so_fibnum;
1417 				INP_WUNLOCK(in6p);
1418 				error = 0;
1419 				break;
1420 			default:
1421 				break;
1422 			}
1423 		}
1424 	} else {		/* level == IPPROTO_IPV6 */
1425 		switch (op) {
1426 
1427 		case SOPT_SET:
1428 			switch (optname) {
1429 			case IPV6_2292PKTOPTIONS:
1430 #ifdef IPV6_PKTOPTIONS
1431 			case IPV6_PKTOPTIONS:
1432 #endif
1433 			{
1434 				struct mbuf *m;
1435 
1436 				error = soopt_getm(sopt, &m); /* XXX */
1437 				if (error != 0)
1438 					break;
1439 				error = soopt_mcopyin(sopt, m); /* XXX */
1440 				if (error != 0)
1441 					break;
1442 				error = ip6_pcbopts(&in6p->in6p_outputopts,
1443 						    m, so, sopt);
1444 				m_freem(m); /* XXX */
1445 				break;
1446 			}
1447 
1448 			/*
1449 			 * Use of some Hop-by-Hop options or some
1450 			 * Destination options, might require special
1451 			 * privilege.  That is, normal applications
1452 			 * (without special privilege) might be forbidden
1453 			 * from setting certain options in outgoing packets,
1454 			 * and might never see certain options in received
1455 			 * packets. [RFC 2292 Section 6]
1456 			 * KAME specific note:
1457 			 *  KAME prevents non-privileged users from sending or
1458 			 *  receiving ANY hbh/dst options in order to avoid
1459 			 *  overhead of parsing options in the kernel.
1460 			 */
1461 			case IPV6_RECVHOPOPTS:
1462 			case IPV6_RECVDSTOPTS:
1463 			case IPV6_RECVRTHDRDSTOPTS:
1464 				if (td != NULL) {
1465 					error = priv_check(td,
1466 					    PRIV_NETINET_SETHDROPTS);
1467 					if (error)
1468 						break;
1469 				}
1470 				/* FALLTHROUGH */
1471 			case IPV6_UNICAST_HOPS:
1472 			case IPV6_HOPLIMIT:
1473 
1474 			case IPV6_RECVPKTINFO:
1475 			case IPV6_RECVHOPLIMIT:
1476 			case IPV6_RECVRTHDR:
1477 			case IPV6_RECVPATHMTU:
1478 			case IPV6_RECVTCLASS:
1479 			case IPV6_RECVFLOWID:
1480 #ifdef	RSS
1481 			case IPV6_RECVRSSBUCKETID:
1482 #endif
1483 			case IPV6_V6ONLY:
1484 			case IPV6_AUTOFLOWLABEL:
1485 			case IPV6_BINDANY:
1486 			case IPV6_BINDMULTI:
1487 #ifdef	RSS
1488 			case IPV6_RSS_LISTEN_BUCKET:
1489 #endif
1490 				if (optname == IPV6_BINDANY && td != NULL) {
1491 					error = priv_check(td,
1492 					    PRIV_NETINET_BINDANY);
1493 					if (error)
1494 						break;
1495 				}
1496 
1497 				if (optlen != sizeof(int)) {
1498 					error = EINVAL;
1499 					break;
1500 				}
1501 				error = sooptcopyin(sopt, &optval,
1502 					sizeof optval, sizeof optval);
1503 				if (error)
1504 					break;
1505 				switch (optname) {
1506 
1507 				case IPV6_UNICAST_HOPS:
1508 					if (optval < -1 || optval >= 256)
1509 						error = EINVAL;
1510 					else {
1511 						/* -1 = kernel default */
1512 						in6p->in6p_hops = optval;
1513 						if ((in6p->inp_vflag &
1514 						     INP_IPV4) != 0)
1515 							in6p->inp_ip_ttl = optval;
1516 					}
1517 					break;
1518 #define OPTSET(bit) \
1519 do { \
1520 	INP_WLOCK(in6p); \
1521 	if (optval) \
1522 		in6p->inp_flags |= (bit); \
1523 	else \
1524 		in6p->inp_flags &= ~(bit); \
1525 	INP_WUNLOCK(in6p); \
1526 } while (/*CONSTCOND*/ 0)
1527 #define OPTSET2292(bit) \
1528 do { \
1529 	INP_WLOCK(in6p); \
1530 	in6p->inp_flags |= IN6P_RFC2292; \
1531 	if (optval) \
1532 		in6p->inp_flags |= (bit); \
1533 	else \
1534 		in6p->inp_flags &= ~(bit); \
1535 	INP_WUNLOCK(in6p); \
1536 } while (/*CONSTCOND*/ 0)
1537 #define OPTBIT(bit) (in6p->inp_flags & (bit) ? 1 : 0)
1538 
1539 #define OPTSET2(bit, val) do {						\
1540 	INP_WLOCK(in6p);						\
1541 	if (val)							\
1542 		in6p->inp_flags2 |= bit;				\
1543 	else								\
1544 		in6p->inp_flags2 &= ~bit;				\
1545 	INP_WUNLOCK(in6p);						\
1546 } while (0)
1547 #define OPTBIT2(bit) (in6p->inp_flags2 & (bit) ? 1 : 0)
1548 
1549 				case IPV6_RECVPKTINFO:
1550 					/* cannot mix with RFC2292 */
1551 					if (OPTBIT(IN6P_RFC2292)) {
1552 						error = EINVAL;
1553 						break;
1554 					}
1555 					OPTSET(IN6P_PKTINFO);
1556 					break;
1557 
1558 				case IPV6_HOPLIMIT:
1559 				{
1560 					struct ip6_pktopts **optp;
1561 
1562 					/* cannot mix with RFC2292 */
1563 					if (OPTBIT(IN6P_RFC2292)) {
1564 						error = EINVAL;
1565 						break;
1566 					}
1567 					optp = &in6p->in6p_outputopts;
1568 					error = ip6_pcbopt(IPV6_HOPLIMIT,
1569 					    (u_char *)&optval, sizeof(optval),
1570 					    optp, (td != NULL) ? td->td_ucred :
1571 					    NULL, uproto);
1572 					break;
1573 				}
1574 
1575 				case IPV6_RECVHOPLIMIT:
1576 					/* cannot mix with RFC2292 */
1577 					if (OPTBIT(IN6P_RFC2292)) {
1578 						error = EINVAL;
1579 						break;
1580 					}
1581 					OPTSET(IN6P_HOPLIMIT);
1582 					break;
1583 
1584 				case IPV6_RECVHOPOPTS:
1585 					/* cannot mix with RFC2292 */
1586 					if (OPTBIT(IN6P_RFC2292)) {
1587 						error = EINVAL;
1588 						break;
1589 					}
1590 					OPTSET(IN6P_HOPOPTS);
1591 					break;
1592 
1593 				case IPV6_RECVDSTOPTS:
1594 					/* cannot mix with RFC2292 */
1595 					if (OPTBIT(IN6P_RFC2292)) {
1596 						error = EINVAL;
1597 						break;
1598 					}
1599 					OPTSET(IN6P_DSTOPTS);
1600 					break;
1601 
1602 				case IPV6_RECVRTHDRDSTOPTS:
1603 					/* cannot mix with RFC2292 */
1604 					if (OPTBIT(IN6P_RFC2292)) {
1605 						error = EINVAL;
1606 						break;
1607 					}
1608 					OPTSET(IN6P_RTHDRDSTOPTS);
1609 					break;
1610 
1611 				case IPV6_RECVRTHDR:
1612 					/* cannot mix with RFC2292 */
1613 					if (OPTBIT(IN6P_RFC2292)) {
1614 						error = EINVAL;
1615 						break;
1616 					}
1617 					OPTSET(IN6P_RTHDR);
1618 					break;
1619 
1620 				case IPV6_RECVPATHMTU:
1621 					/*
1622 					 * We ignore this option for TCP
1623 					 * sockets.
1624 					 * (RFC3542 leaves this case
1625 					 * unspecified.)
1626 					 */
1627 					if (uproto != IPPROTO_TCP)
1628 						OPTSET(IN6P_MTU);
1629 					break;
1630 
1631 				case IPV6_RECVFLOWID:
1632 					OPTSET2(INP_RECVFLOWID, optval);
1633 					break;
1634 
1635 #ifdef	RSS
1636 				case IPV6_RECVRSSBUCKETID:
1637 					OPTSET2(INP_RECVRSSBUCKETID, optval);
1638 					break;
1639 #endif
1640 
1641 				case IPV6_V6ONLY:
1642 					/*
1643 					 * make setsockopt(IPV6_V6ONLY)
1644 					 * available only prior to bind(2).
1645 					 * see ipng mailing list, Jun 22 2001.
1646 					 */
1647 					if (in6p->inp_lport ||
1648 					    !IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_laddr)) {
1649 						error = EINVAL;
1650 						break;
1651 					}
1652 					OPTSET(IN6P_IPV6_V6ONLY);
1653 					if (optval)
1654 						in6p->inp_vflag &= ~INP_IPV4;
1655 					else
1656 						in6p->inp_vflag |= INP_IPV4;
1657 					break;
1658 				case IPV6_RECVTCLASS:
1659 					/* cannot mix with RFC2292 XXX */
1660 					if (OPTBIT(IN6P_RFC2292)) {
1661 						error = EINVAL;
1662 						break;
1663 					}
1664 					OPTSET(IN6P_TCLASS);
1665 					break;
1666 				case IPV6_AUTOFLOWLABEL:
1667 					OPTSET(IN6P_AUTOFLOWLABEL);
1668 					break;
1669 
1670 				case IPV6_BINDANY:
1671 					OPTSET(INP_BINDANY);
1672 					break;
1673 
1674 				case IPV6_BINDMULTI:
1675 					OPTSET2(INP_BINDMULTI, optval);
1676 					break;
1677 #ifdef	RSS
1678 				case IPV6_RSS_LISTEN_BUCKET:
1679 					if ((optval >= 0) &&
1680 					    (optval < rss_getnumbuckets())) {
1681 						in6p->inp_rss_listen_bucket = optval;
1682 						OPTSET2(INP_RSS_BUCKET_SET, 1);
1683 					} else {
1684 						error = EINVAL;
1685 					}
1686 					break;
1687 #endif
1688 				}
1689 				break;
1690 
1691 			case IPV6_TCLASS:
1692 			case IPV6_DONTFRAG:
1693 			case IPV6_USE_MIN_MTU:
1694 			case IPV6_PREFER_TEMPADDR:
1695 				if (optlen != sizeof(optval)) {
1696 					error = EINVAL;
1697 					break;
1698 				}
1699 				error = sooptcopyin(sopt, &optval,
1700 					sizeof optval, sizeof optval);
1701 				if (error)
1702 					break;
1703 				{
1704 					struct ip6_pktopts **optp;
1705 					optp = &in6p->in6p_outputopts;
1706 					error = ip6_pcbopt(optname,
1707 					    (u_char *)&optval, sizeof(optval),
1708 					    optp, (td != NULL) ? td->td_ucred :
1709 					    NULL, uproto);
1710 					break;
1711 				}
1712 
1713 			case IPV6_2292PKTINFO:
1714 			case IPV6_2292HOPLIMIT:
1715 			case IPV6_2292HOPOPTS:
1716 			case IPV6_2292DSTOPTS:
1717 			case IPV6_2292RTHDR:
1718 				/* RFC 2292 */
1719 				if (optlen != sizeof(int)) {
1720 					error = EINVAL;
1721 					break;
1722 				}
1723 				error = sooptcopyin(sopt, &optval,
1724 					sizeof optval, sizeof optval);
1725 				if (error)
1726 					break;
1727 				switch (optname) {
1728 				case IPV6_2292PKTINFO:
1729 					OPTSET2292(IN6P_PKTINFO);
1730 					break;
1731 				case IPV6_2292HOPLIMIT:
1732 					OPTSET2292(IN6P_HOPLIMIT);
1733 					break;
1734 				case IPV6_2292HOPOPTS:
1735 					/*
1736 					 * Check super-user privilege.
1737 					 * See comments for IPV6_RECVHOPOPTS.
1738 					 */
1739 					if (td != NULL) {
1740 						error = priv_check(td,
1741 						    PRIV_NETINET_SETHDROPTS);
1742 						if (error)
1743 							return (error);
1744 					}
1745 					OPTSET2292(IN6P_HOPOPTS);
1746 					break;
1747 				case IPV6_2292DSTOPTS:
1748 					if (td != NULL) {
1749 						error = priv_check(td,
1750 						    PRIV_NETINET_SETHDROPTS);
1751 						if (error)
1752 							return (error);
1753 					}
1754 					OPTSET2292(IN6P_DSTOPTS|IN6P_RTHDRDSTOPTS); /* XXX */
1755 					break;
1756 				case IPV6_2292RTHDR:
1757 					OPTSET2292(IN6P_RTHDR);
1758 					break;
1759 				}
1760 				break;
1761 			case IPV6_PKTINFO:
1762 			case IPV6_HOPOPTS:
1763 			case IPV6_RTHDR:
1764 			case IPV6_DSTOPTS:
1765 			case IPV6_RTHDRDSTOPTS:
1766 			case IPV6_NEXTHOP:
1767 			{
1768 				/* new advanced API (RFC3542) */
1769 				u_char *optbuf;
1770 				u_char optbuf_storage[MCLBYTES];
1771 				int optlen;
1772 				struct ip6_pktopts **optp;
1773 
1774 				/* cannot mix with RFC2292 */
1775 				if (OPTBIT(IN6P_RFC2292)) {
1776 					error = EINVAL;
1777 					break;
1778 				}
1779 
1780 				/*
1781 				 * We only ensure valsize is not too large
1782 				 * here.  Further validation will be done
1783 				 * later.
1784 				 */
1785 				error = sooptcopyin(sopt, optbuf_storage,
1786 				    sizeof(optbuf_storage), 0);
1787 				if (error)
1788 					break;
1789 				optlen = sopt->sopt_valsize;
1790 				optbuf = optbuf_storage;
1791 				optp = &in6p->in6p_outputopts;
1792 				error = ip6_pcbopt(optname, optbuf, optlen,
1793 				    optp, (td != NULL) ? td->td_ucred : NULL,
1794 				    uproto);
1795 				break;
1796 			}
1797 #undef OPTSET
1798 
1799 			case IPV6_MULTICAST_IF:
1800 			case IPV6_MULTICAST_HOPS:
1801 			case IPV6_MULTICAST_LOOP:
1802 			case IPV6_JOIN_GROUP:
1803 			case IPV6_LEAVE_GROUP:
1804 			case IPV6_MSFILTER:
1805 			case MCAST_BLOCK_SOURCE:
1806 			case MCAST_UNBLOCK_SOURCE:
1807 			case MCAST_JOIN_GROUP:
1808 			case MCAST_LEAVE_GROUP:
1809 			case MCAST_JOIN_SOURCE_GROUP:
1810 			case MCAST_LEAVE_SOURCE_GROUP:
1811 				error = ip6_setmoptions(in6p, sopt);
1812 				break;
1813 
1814 			case IPV6_PORTRANGE:
1815 				error = sooptcopyin(sopt, &optval,
1816 				    sizeof optval, sizeof optval);
1817 				if (error)
1818 					break;
1819 
1820 				INP_WLOCK(in6p);
1821 				switch (optval) {
1822 				case IPV6_PORTRANGE_DEFAULT:
1823 					in6p->inp_flags &= ~(INP_LOWPORT);
1824 					in6p->inp_flags &= ~(INP_HIGHPORT);
1825 					break;
1826 
1827 				case IPV6_PORTRANGE_HIGH:
1828 					in6p->inp_flags &= ~(INP_LOWPORT);
1829 					in6p->inp_flags |= INP_HIGHPORT;
1830 					break;
1831 
1832 				case IPV6_PORTRANGE_LOW:
1833 					in6p->inp_flags &= ~(INP_HIGHPORT);
1834 					in6p->inp_flags |= INP_LOWPORT;
1835 					break;
1836 
1837 				default:
1838 					error = EINVAL;
1839 					break;
1840 				}
1841 				INP_WUNLOCK(in6p);
1842 				break;
1843 
1844 #ifdef IPSEC
1845 			case IPV6_IPSEC_POLICY:
1846 			{
1847 				caddr_t req;
1848 				struct mbuf *m;
1849 
1850 				if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */
1851 					break;
1852 				if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */
1853 					break;
1854 				req = mtod(m, caddr_t);
1855 				error = ipsec_set_policy(in6p, optname, req,
1856 				    m->m_len, (sopt->sopt_td != NULL) ?
1857 				    sopt->sopt_td->td_ucred : NULL);
1858 				m_freem(m);
1859 				break;
1860 			}
1861 #endif /* IPSEC */
1862 
1863 			default:
1864 				error = ENOPROTOOPT;
1865 				break;
1866 			}
1867 			break;
1868 
1869 		case SOPT_GET:
1870 			switch (optname) {
1871 
1872 			case IPV6_2292PKTOPTIONS:
1873 #ifdef IPV6_PKTOPTIONS
1874 			case IPV6_PKTOPTIONS:
1875 #endif
1876 				/*
1877 				 * RFC3542 (effectively) deprecated the
1878 				 * semantics of the 2292-style pktoptions.
1879 				 * Since it was not reliable in nature (i.e.,
1880 				 * applications had to expect the lack of some
1881 				 * information after all), it would make sense
1882 				 * to simplify this part by always returning
1883 				 * empty data.
1884 				 */
1885 				sopt->sopt_valsize = 0;
1886 				break;
1887 
1888 			case IPV6_RECVHOPOPTS:
1889 			case IPV6_RECVDSTOPTS:
1890 			case IPV6_RECVRTHDRDSTOPTS:
1891 			case IPV6_UNICAST_HOPS:
1892 			case IPV6_RECVPKTINFO:
1893 			case IPV6_RECVHOPLIMIT:
1894 			case IPV6_RECVRTHDR:
1895 			case IPV6_RECVPATHMTU:
1896 
1897 			case IPV6_V6ONLY:
1898 			case IPV6_PORTRANGE:
1899 			case IPV6_RECVTCLASS:
1900 			case IPV6_AUTOFLOWLABEL:
1901 			case IPV6_BINDANY:
1902 			case IPV6_FLOWID:
1903 			case IPV6_FLOWTYPE:
1904 			case IPV6_RECVFLOWID:
1905 #ifdef	RSS
1906 			case IPV6_RSSBUCKETID:
1907 			case IPV6_RECVRSSBUCKETID:
1908 #endif
1909 			case IPV6_BINDMULTI:
1910 				switch (optname) {
1911 
1912 				case IPV6_RECVHOPOPTS:
1913 					optval = OPTBIT(IN6P_HOPOPTS);
1914 					break;
1915 
1916 				case IPV6_RECVDSTOPTS:
1917 					optval = OPTBIT(IN6P_DSTOPTS);
1918 					break;
1919 
1920 				case IPV6_RECVRTHDRDSTOPTS:
1921 					optval = OPTBIT(IN6P_RTHDRDSTOPTS);
1922 					break;
1923 
1924 				case IPV6_UNICAST_HOPS:
1925 					optval = in6p->in6p_hops;
1926 					break;
1927 
1928 				case IPV6_RECVPKTINFO:
1929 					optval = OPTBIT(IN6P_PKTINFO);
1930 					break;
1931 
1932 				case IPV6_RECVHOPLIMIT:
1933 					optval = OPTBIT(IN6P_HOPLIMIT);
1934 					break;
1935 
1936 				case IPV6_RECVRTHDR:
1937 					optval = OPTBIT(IN6P_RTHDR);
1938 					break;
1939 
1940 				case IPV6_RECVPATHMTU:
1941 					optval = OPTBIT(IN6P_MTU);
1942 					break;
1943 
1944 				case IPV6_V6ONLY:
1945 					optval = OPTBIT(IN6P_IPV6_V6ONLY);
1946 					break;
1947 
1948 				case IPV6_PORTRANGE:
1949 				    {
1950 					int flags;
1951 					flags = in6p->inp_flags;
1952 					if (flags & INP_HIGHPORT)
1953 						optval = IPV6_PORTRANGE_HIGH;
1954 					else if (flags & INP_LOWPORT)
1955 						optval = IPV6_PORTRANGE_LOW;
1956 					else
1957 						optval = 0;
1958 					break;
1959 				    }
1960 				case IPV6_RECVTCLASS:
1961 					optval = OPTBIT(IN6P_TCLASS);
1962 					break;
1963 
1964 				case IPV6_AUTOFLOWLABEL:
1965 					optval = OPTBIT(IN6P_AUTOFLOWLABEL);
1966 					break;
1967 
1968 				case IPV6_BINDANY:
1969 					optval = OPTBIT(INP_BINDANY);
1970 					break;
1971 
1972 				case IPV6_FLOWID:
1973 					optval = in6p->inp_flowid;
1974 					break;
1975 
1976 				case IPV6_FLOWTYPE:
1977 					optval = in6p->inp_flowtype;
1978 					break;
1979 
1980 				case IPV6_RECVFLOWID:
1981 					optval = OPTBIT2(INP_RECVFLOWID);
1982 					break;
1983 #ifdef	RSS
1984 				case IPV6_RSSBUCKETID:
1985 					retval =
1986 					    rss_hash2bucket(in6p->inp_flowid,
1987 					    in6p->inp_flowtype,
1988 					    &rss_bucket);
1989 					if (retval == 0)
1990 						optval = rss_bucket;
1991 					else
1992 						error = EINVAL;
1993 					break;
1994 
1995 				case IPV6_RECVRSSBUCKETID:
1996 					optval = OPTBIT2(INP_RECVRSSBUCKETID);
1997 					break;
1998 #endif
1999 
2000 				case IPV6_BINDMULTI:
2001 					optval = OPTBIT2(INP_BINDMULTI);
2002 					break;
2003 
2004 				}
2005 				if (error)
2006 					break;
2007 				error = sooptcopyout(sopt, &optval,
2008 					sizeof optval);
2009 				break;
2010 
2011 			case IPV6_PATHMTU:
2012 			{
2013 				u_long pmtu = 0;
2014 				struct ip6_mtuinfo mtuinfo;
2015 
2016 				if (!(so->so_state & SS_ISCONNECTED))
2017 					return (ENOTCONN);
2018 				/*
2019 				 * XXX: we dot not consider the case of source
2020 				 * routing, or optional information to specify
2021 				 * the outgoing interface.
2022 				 */
2023 				error = ip6_getpmtu_ctl(so->so_fibnum,
2024 				    &in6p->in6p_faddr, &pmtu);
2025 				if (error)
2026 					break;
2027 				if (pmtu > IPV6_MAXPACKET)
2028 					pmtu = IPV6_MAXPACKET;
2029 
2030 				bzero(&mtuinfo, sizeof(mtuinfo));
2031 				mtuinfo.ip6m_mtu = (u_int32_t)pmtu;
2032 				optdata = (void *)&mtuinfo;
2033 				optdatalen = sizeof(mtuinfo);
2034 				error = sooptcopyout(sopt, optdata,
2035 				    optdatalen);
2036 				break;
2037 			}
2038 
2039 			case IPV6_2292PKTINFO:
2040 			case IPV6_2292HOPLIMIT:
2041 			case IPV6_2292HOPOPTS:
2042 			case IPV6_2292RTHDR:
2043 			case IPV6_2292DSTOPTS:
2044 				switch (optname) {
2045 				case IPV6_2292PKTINFO:
2046 					optval = OPTBIT(IN6P_PKTINFO);
2047 					break;
2048 				case IPV6_2292HOPLIMIT:
2049 					optval = OPTBIT(IN6P_HOPLIMIT);
2050 					break;
2051 				case IPV6_2292HOPOPTS:
2052 					optval = OPTBIT(IN6P_HOPOPTS);
2053 					break;
2054 				case IPV6_2292RTHDR:
2055 					optval = OPTBIT(IN6P_RTHDR);
2056 					break;
2057 				case IPV6_2292DSTOPTS:
2058 					optval = OPTBIT(IN6P_DSTOPTS|IN6P_RTHDRDSTOPTS);
2059 					break;
2060 				}
2061 				error = sooptcopyout(sopt, &optval,
2062 				    sizeof optval);
2063 				break;
2064 			case IPV6_PKTINFO:
2065 			case IPV6_HOPOPTS:
2066 			case IPV6_RTHDR:
2067 			case IPV6_DSTOPTS:
2068 			case IPV6_RTHDRDSTOPTS:
2069 			case IPV6_NEXTHOP:
2070 			case IPV6_TCLASS:
2071 			case IPV6_DONTFRAG:
2072 			case IPV6_USE_MIN_MTU:
2073 			case IPV6_PREFER_TEMPADDR:
2074 				error = ip6_getpcbopt(in6p->in6p_outputopts,
2075 				    optname, sopt);
2076 				break;
2077 
2078 			case IPV6_MULTICAST_IF:
2079 			case IPV6_MULTICAST_HOPS:
2080 			case IPV6_MULTICAST_LOOP:
2081 			case IPV6_MSFILTER:
2082 				error = ip6_getmoptions(in6p, sopt);
2083 				break;
2084 
2085 #ifdef IPSEC
2086 			case IPV6_IPSEC_POLICY:
2087 			  {
2088 				caddr_t req = NULL;
2089 				size_t len = 0;
2090 				struct mbuf *m = NULL;
2091 				struct mbuf **mp = &m;
2092 				size_t ovalsize = sopt->sopt_valsize;
2093 				caddr_t oval = (caddr_t)sopt->sopt_val;
2094 
2095 				error = soopt_getm(sopt, &m); /* XXX */
2096 				if (error != 0)
2097 					break;
2098 				error = soopt_mcopyin(sopt, m); /* XXX */
2099 				if (error != 0)
2100 					break;
2101 				sopt->sopt_valsize = ovalsize;
2102 				sopt->sopt_val = oval;
2103 				if (m) {
2104 					req = mtod(m, caddr_t);
2105 					len = m->m_len;
2106 				}
2107 				error = ipsec_get_policy(in6p, req, len, mp);
2108 				if (error == 0)
2109 					error = soopt_mcopyout(sopt, m); /* XXX */
2110 				if (error == 0 && m)
2111 					m_freem(m);
2112 				break;
2113 			  }
2114 #endif /* IPSEC */
2115 
2116 			default:
2117 				error = ENOPROTOOPT;
2118 				break;
2119 			}
2120 			break;
2121 		}
2122 	}
2123 	return (error);
2124 }
2125 
2126 int
2127 ip6_raw_ctloutput(struct socket *so, struct sockopt *sopt)
2128 {
2129 	int error = 0, optval, optlen;
2130 	const int icmp6off = offsetof(struct icmp6_hdr, icmp6_cksum);
2131 	struct inpcb *in6p = sotoinpcb(so);
2132 	int level, op, optname;
2133 
2134 	level = sopt->sopt_level;
2135 	op = sopt->sopt_dir;
2136 	optname = sopt->sopt_name;
2137 	optlen = sopt->sopt_valsize;
2138 
2139 	if (level != IPPROTO_IPV6) {
2140 		return (EINVAL);
2141 	}
2142 
2143 	switch (optname) {
2144 	case IPV6_CHECKSUM:
2145 		/*
2146 		 * For ICMPv6 sockets, no modification allowed for checksum
2147 		 * offset, permit "no change" values to help existing apps.
2148 		 *
2149 		 * RFC3542 says: "An attempt to set IPV6_CHECKSUM
2150 		 * for an ICMPv6 socket will fail."
2151 		 * The current behavior does not meet RFC3542.
2152 		 */
2153 		switch (op) {
2154 		case SOPT_SET:
2155 			if (optlen != sizeof(int)) {
2156 				error = EINVAL;
2157 				break;
2158 			}
2159 			error = sooptcopyin(sopt, &optval, sizeof(optval),
2160 					    sizeof(optval));
2161 			if (error)
2162 				break;
2163 			if ((optval % 2) != 0) {
2164 				/* the API assumes even offset values */
2165 				error = EINVAL;
2166 			} else if (so->so_proto->pr_protocol ==
2167 			    IPPROTO_ICMPV6) {
2168 				if (optval != icmp6off)
2169 					error = EINVAL;
2170 			} else
2171 				in6p->in6p_cksum = optval;
2172 			break;
2173 
2174 		case SOPT_GET:
2175 			if (so->so_proto->pr_protocol == IPPROTO_ICMPV6)
2176 				optval = icmp6off;
2177 			else
2178 				optval = in6p->in6p_cksum;
2179 
2180 			error = sooptcopyout(sopt, &optval, sizeof(optval));
2181 			break;
2182 
2183 		default:
2184 			error = EINVAL;
2185 			break;
2186 		}
2187 		break;
2188 
2189 	default:
2190 		error = ENOPROTOOPT;
2191 		break;
2192 	}
2193 
2194 	return (error);
2195 }
2196 
2197 /*
2198  * Set up IP6 options in pcb for insertion in output packets or
2199  * specifying behavior of outgoing packets.
2200  */
2201 static int
2202 ip6_pcbopts(struct ip6_pktopts **pktopt, struct mbuf *m,
2203     struct socket *so, struct sockopt *sopt)
2204 {
2205 	struct ip6_pktopts *opt = *pktopt;
2206 	int error = 0;
2207 	struct thread *td = sopt->sopt_td;
2208 
2209 	/* turn off any old options. */
2210 	if (opt) {
2211 #ifdef DIAGNOSTIC
2212 		if (opt->ip6po_pktinfo || opt->ip6po_nexthop ||
2213 		    opt->ip6po_hbh || opt->ip6po_dest1 || opt->ip6po_dest2 ||
2214 		    opt->ip6po_rhinfo.ip6po_rhi_rthdr)
2215 			printf("ip6_pcbopts: all specified options are cleared.\n");
2216 #endif
2217 		ip6_clearpktopts(opt, -1);
2218 	} else
2219 		opt = malloc(sizeof(*opt), M_IP6OPT, M_WAITOK);
2220 	*pktopt = NULL;
2221 
2222 	if (!m || m->m_len == 0) {
2223 		/*
2224 		 * Only turning off any previous options, regardless of
2225 		 * whether the opt is just created or given.
2226 		 */
2227 		free(opt, M_IP6OPT);
2228 		return (0);
2229 	}
2230 
2231 	/*  set options specified by user. */
2232 	if ((error = ip6_setpktopts(m, opt, NULL, (td != NULL) ?
2233 	    td->td_ucred : NULL, so->so_proto->pr_protocol)) != 0) {
2234 		ip6_clearpktopts(opt, -1); /* XXX: discard all options */
2235 		free(opt, M_IP6OPT);
2236 		return (error);
2237 	}
2238 	*pktopt = opt;
2239 	return (0);
2240 }
2241 
2242 /*
2243  * initialize ip6_pktopts.  beware that there are non-zero default values in
2244  * the struct.
2245  */
2246 void
2247 ip6_initpktopts(struct ip6_pktopts *opt)
2248 {
2249 
2250 	bzero(opt, sizeof(*opt));
2251 	opt->ip6po_hlim = -1;	/* -1 means default hop limit */
2252 	opt->ip6po_tclass = -1;	/* -1 means default traffic class */
2253 	opt->ip6po_minmtu = IP6PO_MINMTU_MCASTONLY;
2254 	opt->ip6po_prefer_tempaddr = IP6PO_TEMPADDR_SYSTEM;
2255 }
2256 
2257 static int
2258 ip6_pcbopt(int optname, u_char *buf, int len, struct ip6_pktopts **pktopt,
2259     struct ucred *cred, int uproto)
2260 {
2261 	struct ip6_pktopts *opt;
2262 
2263 	if (*pktopt == NULL) {
2264 		*pktopt = malloc(sizeof(struct ip6_pktopts), M_IP6OPT,
2265 		    M_WAITOK);
2266 		ip6_initpktopts(*pktopt);
2267 	}
2268 	opt = *pktopt;
2269 
2270 	return (ip6_setpktopt(optname, buf, len, opt, cred, 1, 0, uproto));
2271 }
2272 
2273 static int
2274 ip6_getpcbopt(struct ip6_pktopts *pktopt, int optname, struct sockopt *sopt)
2275 {
2276 	void *optdata = NULL;
2277 	int optdatalen = 0;
2278 	struct ip6_ext *ip6e;
2279 	int error = 0;
2280 	struct in6_pktinfo null_pktinfo;
2281 	int deftclass = 0, on;
2282 	int defminmtu = IP6PO_MINMTU_MCASTONLY;
2283 	int defpreftemp = IP6PO_TEMPADDR_SYSTEM;
2284 
2285 	switch (optname) {
2286 	case IPV6_PKTINFO:
2287 		optdata = (void *)&null_pktinfo;
2288 		if (pktopt && pktopt->ip6po_pktinfo) {
2289 			bcopy(pktopt->ip6po_pktinfo, &null_pktinfo,
2290 			    sizeof(null_pktinfo));
2291 			in6_clearscope(&null_pktinfo.ipi6_addr);
2292 		} else {
2293 			/* XXX: we don't have to do this every time... */
2294 			bzero(&null_pktinfo, sizeof(null_pktinfo));
2295 		}
2296 		optdatalen = sizeof(struct in6_pktinfo);
2297 		break;
2298 	case IPV6_TCLASS:
2299 		if (pktopt && pktopt->ip6po_tclass >= 0)
2300 			optdata = (void *)&pktopt->ip6po_tclass;
2301 		else
2302 			optdata = (void *)&deftclass;
2303 		optdatalen = sizeof(int);
2304 		break;
2305 	case IPV6_HOPOPTS:
2306 		if (pktopt && pktopt->ip6po_hbh) {
2307 			optdata = (void *)pktopt->ip6po_hbh;
2308 			ip6e = (struct ip6_ext *)pktopt->ip6po_hbh;
2309 			optdatalen = (ip6e->ip6e_len + 1) << 3;
2310 		}
2311 		break;
2312 	case IPV6_RTHDR:
2313 		if (pktopt && pktopt->ip6po_rthdr) {
2314 			optdata = (void *)pktopt->ip6po_rthdr;
2315 			ip6e = (struct ip6_ext *)pktopt->ip6po_rthdr;
2316 			optdatalen = (ip6e->ip6e_len + 1) << 3;
2317 		}
2318 		break;
2319 	case IPV6_RTHDRDSTOPTS:
2320 		if (pktopt && pktopt->ip6po_dest1) {
2321 			optdata = (void *)pktopt->ip6po_dest1;
2322 			ip6e = (struct ip6_ext *)pktopt->ip6po_dest1;
2323 			optdatalen = (ip6e->ip6e_len + 1) << 3;
2324 		}
2325 		break;
2326 	case IPV6_DSTOPTS:
2327 		if (pktopt && pktopt->ip6po_dest2) {
2328 			optdata = (void *)pktopt->ip6po_dest2;
2329 			ip6e = (struct ip6_ext *)pktopt->ip6po_dest2;
2330 			optdatalen = (ip6e->ip6e_len + 1) << 3;
2331 		}
2332 		break;
2333 	case IPV6_NEXTHOP:
2334 		if (pktopt && pktopt->ip6po_nexthop) {
2335 			optdata = (void *)pktopt->ip6po_nexthop;
2336 			optdatalen = pktopt->ip6po_nexthop->sa_len;
2337 		}
2338 		break;
2339 	case IPV6_USE_MIN_MTU:
2340 		if (pktopt)
2341 			optdata = (void *)&pktopt->ip6po_minmtu;
2342 		else
2343 			optdata = (void *)&defminmtu;
2344 		optdatalen = sizeof(int);
2345 		break;
2346 	case IPV6_DONTFRAG:
2347 		if (pktopt && ((pktopt->ip6po_flags) & IP6PO_DONTFRAG))
2348 			on = 1;
2349 		else
2350 			on = 0;
2351 		optdata = (void *)&on;
2352 		optdatalen = sizeof(on);
2353 		break;
2354 	case IPV6_PREFER_TEMPADDR:
2355 		if (pktopt)
2356 			optdata = (void *)&pktopt->ip6po_prefer_tempaddr;
2357 		else
2358 			optdata = (void *)&defpreftemp;
2359 		optdatalen = sizeof(int);
2360 		break;
2361 	default:		/* should not happen */
2362 #ifdef DIAGNOSTIC
2363 		panic("ip6_getpcbopt: unexpected option\n");
2364 #endif
2365 		return (ENOPROTOOPT);
2366 	}
2367 
2368 	error = sooptcopyout(sopt, optdata, optdatalen);
2369 
2370 	return (error);
2371 }
2372 
2373 void
2374 ip6_clearpktopts(struct ip6_pktopts *pktopt, int optname)
2375 {
2376 	if (pktopt == NULL)
2377 		return;
2378 
2379 	if (optname == -1 || optname == IPV6_PKTINFO) {
2380 		if (pktopt->ip6po_pktinfo)
2381 			free(pktopt->ip6po_pktinfo, M_IP6OPT);
2382 		pktopt->ip6po_pktinfo = NULL;
2383 	}
2384 	if (optname == -1 || optname == IPV6_HOPLIMIT)
2385 		pktopt->ip6po_hlim = -1;
2386 	if (optname == -1 || optname == IPV6_TCLASS)
2387 		pktopt->ip6po_tclass = -1;
2388 	if (optname == -1 || optname == IPV6_NEXTHOP) {
2389 		if (pktopt->ip6po_nextroute.ro_rt) {
2390 			RTFREE(pktopt->ip6po_nextroute.ro_rt);
2391 			pktopt->ip6po_nextroute.ro_rt = NULL;
2392 		}
2393 		if (pktopt->ip6po_nexthop)
2394 			free(pktopt->ip6po_nexthop, M_IP6OPT);
2395 		pktopt->ip6po_nexthop = NULL;
2396 	}
2397 	if (optname == -1 || optname == IPV6_HOPOPTS) {
2398 		if (pktopt->ip6po_hbh)
2399 			free(pktopt->ip6po_hbh, M_IP6OPT);
2400 		pktopt->ip6po_hbh = NULL;
2401 	}
2402 	if (optname == -1 || optname == IPV6_RTHDRDSTOPTS) {
2403 		if (pktopt->ip6po_dest1)
2404 			free(pktopt->ip6po_dest1, M_IP6OPT);
2405 		pktopt->ip6po_dest1 = NULL;
2406 	}
2407 	if (optname == -1 || optname == IPV6_RTHDR) {
2408 		if (pktopt->ip6po_rhinfo.ip6po_rhi_rthdr)
2409 			free(pktopt->ip6po_rhinfo.ip6po_rhi_rthdr, M_IP6OPT);
2410 		pktopt->ip6po_rhinfo.ip6po_rhi_rthdr = NULL;
2411 		if (pktopt->ip6po_route.ro_rt) {
2412 			RTFREE(pktopt->ip6po_route.ro_rt);
2413 			pktopt->ip6po_route.ro_rt = NULL;
2414 		}
2415 	}
2416 	if (optname == -1 || optname == IPV6_DSTOPTS) {
2417 		if (pktopt->ip6po_dest2)
2418 			free(pktopt->ip6po_dest2, M_IP6OPT);
2419 		pktopt->ip6po_dest2 = NULL;
2420 	}
2421 }
2422 
2423 #define PKTOPT_EXTHDRCPY(type) \
2424 do {\
2425 	if (src->type) {\
2426 		int hlen = (((struct ip6_ext *)src->type)->ip6e_len + 1) << 3;\
2427 		dst->type = malloc(hlen, M_IP6OPT, canwait);\
2428 		if (dst->type == NULL && canwait == M_NOWAIT)\
2429 			goto bad;\
2430 		bcopy(src->type, dst->type, hlen);\
2431 	}\
2432 } while (/*CONSTCOND*/ 0)
2433 
2434 static int
2435 copypktopts(struct ip6_pktopts *dst, struct ip6_pktopts *src, int canwait)
2436 {
2437 	if (dst == NULL || src == NULL)  {
2438 		printf("ip6_clearpktopts: invalid argument\n");
2439 		return (EINVAL);
2440 	}
2441 
2442 	dst->ip6po_hlim = src->ip6po_hlim;
2443 	dst->ip6po_tclass = src->ip6po_tclass;
2444 	dst->ip6po_flags = src->ip6po_flags;
2445 	dst->ip6po_minmtu = src->ip6po_minmtu;
2446 	dst->ip6po_prefer_tempaddr = src->ip6po_prefer_tempaddr;
2447 	if (src->ip6po_pktinfo) {
2448 		dst->ip6po_pktinfo = malloc(sizeof(*dst->ip6po_pktinfo),
2449 		    M_IP6OPT, canwait);
2450 		if (dst->ip6po_pktinfo == NULL)
2451 			goto bad;
2452 		*dst->ip6po_pktinfo = *src->ip6po_pktinfo;
2453 	}
2454 	if (src->ip6po_nexthop) {
2455 		dst->ip6po_nexthop = malloc(src->ip6po_nexthop->sa_len,
2456 		    M_IP6OPT, canwait);
2457 		if (dst->ip6po_nexthop == NULL)
2458 			goto bad;
2459 		bcopy(src->ip6po_nexthop, dst->ip6po_nexthop,
2460 		    src->ip6po_nexthop->sa_len);
2461 	}
2462 	PKTOPT_EXTHDRCPY(ip6po_hbh);
2463 	PKTOPT_EXTHDRCPY(ip6po_dest1);
2464 	PKTOPT_EXTHDRCPY(ip6po_dest2);
2465 	PKTOPT_EXTHDRCPY(ip6po_rthdr); /* not copy the cached route */
2466 	return (0);
2467 
2468   bad:
2469 	ip6_clearpktopts(dst, -1);
2470 	return (ENOBUFS);
2471 }
2472 #undef PKTOPT_EXTHDRCPY
2473 
2474 struct ip6_pktopts *
2475 ip6_copypktopts(struct ip6_pktopts *src, int canwait)
2476 {
2477 	int error;
2478 	struct ip6_pktopts *dst;
2479 
2480 	dst = malloc(sizeof(*dst), M_IP6OPT, canwait);
2481 	if (dst == NULL)
2482 		return (NULL);
2483 	ip6_initpktopts(dst);
2484 
2485 	if ((error = copypktopts(dst, src, canwait)) != 0) {
2486 		free(dst, M_IP6OPT);
2487 		return (NULL);
2488 	}
2489 
2490 	return (dst);
2491 }
2492 
2493 void
2494 ip6_freepcbopts(struct ip6_pktopts *pktopt)
2495 {
2496 	if (pktopt == NULL)
2497 		return;
2498 
2499 	ip6_clearpktopts(pktopt, -1);
2500 
2501 	free(pktopt, M_IP6OPT);
2502 }
2503 
2504 /*
2505  * Set IPv6 outgoing packet options based on advanced API.
2506  */
2507 int
2508 ip6_setpktopts(struct mbuf *control, struct ip6_pktopts *opt,
2509     struct ip6_pktopts *stickyopt, struct ucred *cred, int uproto)
2510 {
2511 	struct cmsghdr *cm = NULL;
2512 
2513 	if (control == NULL || opt == NULL)
2514 		return (EINVAL);
2515 
2516 	ip6_initpktopts(opt);
2517 	if (stickyopt) {
2518 		int error;
2519 
2520 		/*
2521 		 * If stickyopt is provided, make a local copy of the options
2522 		 * for this particular packet, then override them by ancillary
2523 		 * objects.
2524 		 * XXX: copypktopts() does not copy the cached route to a next
2525 		 * hop (if any).  This is not very good in terms of efficiency,
2526 		 * but we can allow this since this option should be rarely
2527 		 * used.
2528 		 */
2529 		if ((error = copypktopts(opt, stickyopt, M_NOWAIT)) != 0)
2530 			return (error);
2531 	}
2532 
2533 	/*
2534 	 * XXX: Currently, we assume all the optional information is stored
2535 	 * in a single mbuf.
2536 	 */
2537 	if (control->m_next)
2538 		return (EINVAL);
2539 
2540 	for (; control->m_len > 0; control->m_data += CMSG_ALIGN(cm->cmsg_len),
2541 	    control->m_len -= CMSG_ALIGN(cm->cmsg_len)) {
2542 		int error;
2543 
2544 		if (control->m_len < CMSG_LEN(0))
2545 			return (EINVAL);
2546 
2547 		cm = mtod(control, struct cmsghdr *);
2548 		if (cm->cmsg_len == 0 || cm->cmsg_len > control->m_len)
2549 			return (EINVAL);
2550 		if (cm->cmsg_level != IPPROTO_IPV6)
2551 			continue;
2552 
2553 		error = ip6_setpktopt(cm->cmsg_type, CMSG_DATA(cm),
2554 		    cm->cmsg_len - CMSG_LEN(0), opt, cred, 0, 1, uproto);
2555 		if (error)
2556 			return (error);
2557 	}
2558 
2559 	return (0);
2560 }
2561 
2562 /*
2563  * Set a particular packet option, as a sticky option or an ancillary data
2564  * item.  "len" can be 0 only when it's a sticky option.
2565  * We have 4 cases of combination of "sticky" and "cmsg":
2566  * "sticky=0, cmsg=0": impossible
2567  * "sticky=0, cmsg=1": RFC2292 or RFC3542 ancillary data
2568  * "sticky=1, cmsg=0": RFC3542 socket option
2569  * "sticky=1, cmsg=1": RFC2292 socket option
2570  */
2571 static int
2572 ip6_setpktopt(int optname, u_char *buf, int len, struct ip6_pktopts *opt,
2573     struct ucred *cred, int sticky, int cmsg, int uproto)
2574 {
2575 	int minmtupolicy, preftemp;
2576 	int error;
2577 
2578 	if (!sticky && !cmsg) {
2579 #ifdef DIAGNOSTIC
2580 		printf("ip6_setpktopt: impossible case\n");
2581 #endif
2582 		return (EINVAL);
2583 	}
2584 
2585 	/*
2586 	 * IPV6_2292xxx is for backward compatibility to RFC2292, and should
2587 	 * not be specified in the context of RFC3542.  Conversely,
2588 	 * RFC3542 types should not be specified in the context of RFC2292.
2589 	 */
2590 	if (!cmsg) {
2591 		switch (optname) {
2592 		case IPV6_2292PKTINFO:
2593 		case IPV6_2292HOPLIMIT:
2594 		case IPV6_2292NEXTHOP:
2595 		case IPV6_2292HOPOPTS:
2596 		case IPV6_2292DSTOPTS:
2597 		case IPV6_2292RTHDR:
2598 		case IPV6_2292PKTOPTIONS:
2599 			return (ENOPROTOOPT);
2600 		}
2601 	}
2602 	if (sticky && cmsg) {
2603 		switch (optname) {
2604 		case IPV6_PKTINFO:
2605 		case IPV6_HOPLIMIT:
2606 		case IPV6_NEXTHOP:
2607 		case IPV6_HOPOPTS:
2608 		case IPV6_DSTOPTS:
2609 		case IPV6_RTHDRDSTOPTS:
2610 		case IPV6_RTHDR:
2611 		case IPV6_USE_MIN_MTU:
2612 		case IPV6_DONTFRAG:
2613 		case IPV6_TCLASS:
2614 		case IPV6_PREFER_TEMPADDR: /* XXX: not an RFC3542 option */
2615 			return (ENOPROTOOPT);
2616 		}
2617 	}
2618 
2619 	switch (optname) {
2620 	case IPV6_2292PKTINFO:
2621 	case IPV6_PKTINFO:
2622 	{
2623 		struct ifnet *ifp = NULL;
2624 		struct in6_pktinfo *pktinfo;
2625 
2626 		if (len != sizeof(struct in6_pktinfo))
2627 			return (EINVAL);
2628 
2629 		pktinfo = (struct in6_pktinfo *)buf;
2630 
2631 		/*
2632 		 * An application can clear any sticky IPV6_PKTINFO option by
2633 		 * doing a "regular" setsockopt with ipi6_addr being
2634 		 * in6addr_any and ipi6_ifindex being zero.
2635 		 * [RFC 3542, Section 6]
2636 		 */
2637 		if (optname == IPV6_PKTINFO && opt->ip6po_pktinfo &&
2638 		    pktinfo->ipi6_ifindex == 0 &&
2639 		    IN6_IS_ADDR_UNSPECIFIED(&pktinfo->ipi6_addr)) {
2640 			ip6_clearpktopts(opt, optname);
2641 			break;
2642 		}
2643 
2644 		if (uproto == IPPROTO_TCP && optname == IPV6_PKTINFO &&
2645 		    sticky && !IN6_IS_ADDR_UNSPECIFIED(&pktinfo->ipi6_addr)) {
2646 			return (EINVAL);
2647 		}
2648 		if (IN6_IS_ADDR_MULTICAST(&pktinfo->ipi6_addr))
2649 			return (EINVAL);
2650 		/* validate the interface index if specified. */
2651 		if (pktinfo->ipi6_ifindex > V_if_index)
2652 			 return (ENXIO);
2653 		if (pktinfo->ipi6_ifindex) {
2654 			ifp = ifnet_byindex(pktinfo->ipi6_ifindex);
2655 			if (ifp == NULL)
2656 				return (ENXIO);
2657 		}
2658 		if (ifp != NULL && (
2659 		    ND_IFINFO(ifp)->flags & ND6_IFF_IFDISABLED))
2660 			return (ENETDOWN);
2661 
2662 		if (ifp != NULL &&
2663 		    !IN6_IS_ADDR_UNSPECIFIED(&pktinfo->ipi6_addr)) {
2664 			struct in6_ifaddr *ia;
2665 
2666 			in6_setscope(&pktinfo->ipi6_addr, ifp, NULL);
2667 			ia = in6ifa_ifpwithaddr(ifp, &pktinfo->ipi6_addr);
2668 			if (ia == NULL)
2669 				return (EADDRNOTAVAIL);
2670 			ifa_free(&ia->ia_ifa);
2671 		}
2672 		/*
2673 		 * We store the address anyway, and let in6_selectsrc()
2674 		 * validate the specified address.  This is because ipi6_addr
2675 		 * may not have enough information about its scope zone, and
2676 		 * we may need additional information (such as outgoing
2677 		 * interface or the scope zone of a destination address) to
2678 		 * disambiguate the scope.
2679 		 * XXX: the delay of the validation may confuse the
2680 		 * application when it is used as a sticky option.
2681 		 */
2682 		if (opt->ip6po_pktinfo == NULL) {
2683 			opt->ip6po_pktinfo = malloc(sizeof(*pktinfo),
2684 			    M_IP6OPT, M_NOWAIT);
2685 			if (opt->ip6po_pktinfo == NULL)
2686 				return (ENOBUFS);
2687 		}
2688 		bcopy(pktinfo, opt->ip6po_pktinfo, sizeof(*pktinfo));
2689 		break;
2690 	}
2691 
2692 	case IPV6_2292HOPLIMIT:
2693 	case IPV6_HOPLIMIT:
2694 	{
2695 		int *hlimp;
2696 
2697 		/*
2698 		 * RFC 3542 deprecated the usage of sticky IPV6_HOPLIMIT
2699 		 * to simplify the ordering among hoplimit options.
2700 		 */
2701 		if (optname == IPV6_HOPLIMIT && sticky)
2702 			return (ENOPROTOOPT);
2703 
2704 		if (len != sizeof(int))
2705 			return (EINVAL);
2706 		hlimp = (int *)buf;
2707 		if (*hlimp < -1 || *hlimp > 255)
2708 			return (EINVAL);
2709 
2710 		opt->ip6po_hlim = *hlimp;
2711 		break;
2712 	}
2713 
2714 	case IPV6_TCLASS:
2715 	{
2716 		int tclass;
2717 
2718 		if (len != sizeof(int))
2719 			return (EINVAL);
2720 		tclass = *(int *)buf;
2721 		if (tclass < -1 || tclass > 255)
2722 			return (EINVAL);
2723 
2724 		opt->ip6po_tclass = tclass;
2725 		break;
2726 	}
2727 
2728 	case IPV6_2292NEXTHOP:
2729 	case IPV6_NEXTHOP:
2730 		if (cred != NULL) {
2731 			error = priv_check_cred(cred,
2732 			    PRIV_NETINET_SETHDROPTS, 0);
2733 			if (error)
2734 				return (error);
2735 		}
2736 
2737 		if (len == 0) {	/* just remove the option */
2738 			ip6_clearpktopts(opt, IPV6_NEXTHOP);
2739 			break;
2740 		}
2741 
2742 		/* check if cmsg_len is large enough for sa_len */
2743 		if (len < sizeof(struct sockaddr) || len < *buf)
2744 			return (EINVAL);
2745 
2746 		switch (((struct sockaddr *)buf)->sa_family) {
2747 		case AF_INET6:
2748 		{
2749 			struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)buf;
2750 			int error;
2751 
2752 			if (sa6->sin6_len != sizeof(struct sockaddr_in6))
2753 				return (EINVAL);
2754 
2755 			if (IN6_IS_ADDR_UNSPECIFIED(&sa6->sin6_addr) ||
2756 			    IN6_IS_ADDR_MULTICAST(&sa6->sin6_addr)) {
2757 				return (EINVAL);
2758 			}
2759 			if ((error = sa6_embedscope(sa6, V_ip6_use_defzone))
2760 			    != 0) {
2761 				return (error);
2762 			}
2763 			break;
2764 		}
2765 		case AF_LINK:	/* should eventually be supported */
2766 		default:
2767 			return (EAFNOSUPPORT);
2768 		}
2769 
2770 		/* turn off the previous option, then set the new option. */
2771 		ip6_clearpktopts(opt, IPV6_NEXTHOP);
2772 		opt->ip6po_nexthop = malloc(*buf, M_IP6OPT, M_NOWAIT);
2773 		if (opt->ip6po_nexthop == NULL)
2774 			return (ENOBUFS);
2775 		bcopy(buf, opt->ip6po_nexthop, *buf);
2776 		break;
2777 
2778 	case IPV6_2292HOPOPTS:
2779 	case IPV6_HOPOPTS:
2780 	{
2781 		struct ip6_hbh *hbh;
2782 		int hbhlen;
2783 
2784 		/*
2785 		 * XXX: We don't allow a non-privileged user to set ANY HbH
2786 		 * options, since per-option restriction has too much
2787 		 * overhead.
2788 		 */
2789 		if (cred != NULL) {
2790 			error = priv_check_cred(cred,
2791 			    PRIV_NETINET_SETHDROPTS, 0);
2792 			if (error)
2793 				return (error);
2794 		}
2795 
2796 		if (len == 0) {
2797 			ip6_clearpktopts(opt, IPV6_HOPOPTS);
2798 			break;	/* just remove the option */
2799 		}
2800 
2801 		/* message length validation */
2802 		if (len < sizeof(struct ip6_hbh))
2803 			return (EINVAL);
2804 		hbh = (struct ip6_hbh *)buf;
2805 		hbhlen = (hbh->ip6h_len + 1) << 3;
2806 		if (len != hbhlen)
2807 			return (EINVAL);
2808 
2809 		/* turn off the previous option, then set the new option. */
2810 		ip6_clearpktopts(opt, IPV6_HOPOPTS);
2811 		opt->ip6po_hbh = malloc(hbhlen, M_IP6OPT, M_NOWAIT);
2812 		if (opt->ip6po_hbh == NULL)
2813 			return (ENOBUFS);
2814 		bcopy(hbh, opt->ip6po_hbh, hbhlen);
2815 
2816 		break;
2817 	}
2818 
2819 	case IPV6_2292DSTOPTS:
2820 	case IPV6_DSTOPTS:
2821 	case IPV6_RTHDRDSTOPTS:
2822 	{
2823 		struct ip6_dest *dest, **newdest = NULL;
2824 		int destlen;
2825 
2826 		if (cred != NULL) { /* XXX: see the comment for IPV6_HOPOPTS */
2827 			error = priv_check_cred(cred,
2828 			    PRIV_NETINET_SETHDROPTS, 0);
2829 			if (error)
2830 				return (error);
2831 		}
2832 
2833 		if (len == 0) {
2834 			ip6_clearpktopts(opt, optname);
2835 			break;	/* just remove the option */
2836 		}
2837 
2838 		/* message length validation */
2839 		if (len < sizeof(struct ip6_dest))
2840 			return (EINVAL);
2841 		dest = (struct ip6_dest *)buf;
2842 		destlen = (dest->ip6d_len + 1) << 3;
2843 		if (len != destlen)
2844 			return (EINVAL);
2845 
2846 		/*
2847 		 * Determine the position that the destination options header
2848 		 * should be inserted; before or after the routing header.
2849 		 */
2850 		switch (optname) {
2851 		case IPV6_2292DSTOPTS:
2852 			/*
2853 			 * The old advacned API is ambiguous on this point.
2854 			 * Our approach is to determine the position based
2855 			 * according to the existence of a routing header.
2856 			 * Note, however, that this depends on the order of the
2857 			 * extension headers in the ancillary data; the 1st
2858 			 * part of the destination options header must appear
2859 			 * before the routing header in the ancillary data,
2860 			 * too.
2861 			 * RFC3542 solved the ambiguity by introducing
2862 			 * separate ancillary data or option types.
2863 			 */
2864 			if (opt->ip6po_rthdr == NULL)
2865 				newdest = &opt->ip6po_dest1;
2866 			else
2867 				newdest = &opt->ip6po_dest2;
2868 			break;
2869 		case IPV6_RTHDRDSTOPTS:
2870 			newdest = &opt->ip6po_dest1;
2871 			break;
2872 		case IPV6_DSTOPTS:
2873 			newdest = &opt->ip6po_dest2;
2874 			break;
2875 		}
2876 
2877 		/* turn off the previous option, then set the new option. */
2878 		ip6_clearpktopts(opt, optname);
2879 		*newdest = malloc(destlen, M_IP6OPT, M_NOWAIT);
2880 		if (*newdest == NULL)
2881 			return (ENOBUFS);
2882 		bcopy(dest, *newdest, destlen);
2883 
2884 		break;
2885 	}
2886 
2887 	case IPV6_2292RTHDR:
2888 	case IPV6_RTHDR:
2889 	{
2890 		struct ip6_rthdr *rth;
2891 		int rthlen;
2892 
2893 		if (len == 0) {
2894 			ip6_clearpktopts(opt, IPV6_RTHDR);
2895 			break;	/* just remove the option */
2896 		}
2897 
2898 		/* message length validation */
2899 		if (len < sizeof(struct ip6_rthdr))
2900 			return (EINVAL);
2901 		rth = (struct ip6_rthdr *)buf;
2902 		rthlen = (rth->ip6r_len + 1) << 3;
2903 		if (len != rthlen)
2904 			return (EINVAL);
2905 
2906 		switch (rth->ip6r_type) {
2907 		case IPV6_RTHDR_TYPE_0:
2908 			if (rth->ip6r_len == 0)	/* must contain one addr */
2909 				return (EINVAL);
2910 			if (rth->ip6r_len % 2) /* length must be even */
2911 				return (EINVAL);
2912 			if (rth->ip6r_len / 2 != rth->ip6r_segleft)
2913 				return (EINVAL);
2914 			break;
2915 		default:
2916 			return (EINVAL);	/* not supported */
2917 		}
2918 
2919 		/* turn off the previous option */
2920 		ip6_clearpktopts(opt, IPV6_RTHDR);
2921 		opt->ip6po_rthdr = malloc(rthlen, M_IP6OPT, M_NOWAIT);
2922 		if (opt->ip6po_rthdr == NULL)
2923 			return (ENOBUFS);
2924 		bcopy(rth, opt->ip6po_rthdr, rthlen);
2925 
2926 		break;
2927 	}
2928 
2929 	case IPV6_USE_MIN_MTU:
2930 		if (len != sizeof(int))
2931 			return (EINVAL);
2932 		minmtupolicy = *(int *)buf;
2933 		if (minmtupolicy != IP6PO_MINMTU_MCASTONLY &&
2934 		    minmtupolicy != IP6PO_MINMTU_DISABLE &&
2935 		    minmtupolicy != IP6PO_MINMTU_ALL) {
2936 			return (EINVAL);
2937 		}
2938 		opt->ip6po_minmtu = minmtupolicy;
2939 		break;
2940 
2941 	case IPV6_DONTFRAG:
2942 		if (len != sizeof(int))
2943 			return (EINVAL);
2944 
2945 		if (uproto == IPPROTO_TCP || *(int *)buf == 0) {
2946 			/*
2947 			 * we ignore this option for TCP sockets.
2948 			 * (RFC3542 leaves this case unspecified.)
2949 			 */
2950 			opt->ip6po_flags &= ~IP6PO_DONTFRAG;
2951 		} else
2952 			opt->ip6po_flags |= IP6PO_DONTFRAG;
2953 		break;
2954 
2955 	case IPV6_PREFER_TEMPADDR:
2956 		if (len != sizeof(int))
2957 			return (EINVAL);
2958 		preftemp = *(int *)buf;
2959 		if (preftemp != IP6PO_TEMPADDR_SYSTEM &&
2960 		    preftemp != IP6PO_TEMPADDR_NOTPREFER &&
2961 		    preftemp != IP6PO_TEMPADDR_PREFER) {
2962 			return (EINVAL);
2963 		}
2964 		opt->ip6po_prefer_tempaddr = preftemp;
2965 		break;
2966 
2967 	default:
2968 		return (ENOPROTOOPT);
2969 	} /* end of switch */
2970 
2971 	return (0);
2972 }
2973 
2974 /*
2975  * Routine called from ip6_output() to loop back a copy of an IP6 multicast
2976  * packet to the input queue of a specified interface.  Note that this
2977  * calls the output routine of the loopback "driver", but with an interface
2978  * pointer that might NOT be &loif -- easier than replicating that code here.
2979  */
2980 void
2981 ip6_mloopback(struct ifnet *ifp, struct mbuf *m)
2982 {
2983 	struct mbuf *copym;
2984 	struct ip6_hdr *ip6;
2985 
2986 	copym = m_copy(m, 0, M_COPYALL);
2987 	if (copym == NULL)
2988 		return;
2989 
2990 	/*
2991 	 * Make sure to deep-copy IPv6 header portion in case the data
2992 	 * is in an mbuf cluster, so that we can safely override the IPv6
2993 	 * header portion later.
2994 	 */
2995 	if (!M_WRITABLE(copym) ||
2996 	    copym->m_len < sizeof(struct ip6_hdr)) {
2997 		copym = m_pullup(copym, sizeof(struct ip6_hdr));
2998 		if (copym == NULL)
2999 			return;
3000 	}
3001 	ip6 = mtod(copym, struct ip6_hdr *);
3002 	/*
3003 	 * clear embedded scope identifiers if necessary.
3004 	 * in6_clearscope will touch the addresses only when necessary.
3005 	 */
3006 	in6_clearscope(&ip6->ip6_src);
3007 	in6_clearscope(&ip6->ip6_dst);
3008 	if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
3009 		copym->m_pkthdr.csum_flags |= CSUM_DATA_VALID_IPV6 |
3010 		    CSUM_PSEUDO_HDR;
3011 		copym->m_pkthdr.csum_data = 0xffff;
3012 	}
3013 	if_simloop(ifp, copym, AF_INET6, 0);
3014 }
3015 
3016 /*
3017  * Chop IPv6 header off from the payload.
3018  */
3019 static int
3020 ip6_splithdr(struct mbuf *m, struct ip6_exthdrs *exthdrs)
3021 {
3022 	struct mbuf *mh;
3023 	struct ip6_hdr *ip6;
3024 
3025 	ip6 = mtod(m, struct ip6_hdr *);
3026 	if (m->m_len > sizeof(*ip6)) {
3027 		mh = m_gethdr(M_NOWAIT, MT_DATA);
3028 		if (mh == NULL) {
3029 			m_freem(m);
3030 			return ENOBUFS;
3031 		}
3032 		m_move_pkthdr(mh, m);
3033 		M_ALIGN(mh, sizeof(*ip6));
3034 		m->m_len -= sizeof(*ip6);
3035 		m->m_data += sizeof(*ip6);
3036 		mh->m_next = m;
3037 		m = mh;
3038 		m->m_len = sizeof(*ip6);
3039 		bcopy((caddr_t)ip6, mtod(m, caddr_t), sizeof(*ip6));
3040 	}
3041 	exthdrs->ip6e_ip6 = m;
3042 	return 0;
3043 }
3044 
3045 /*
3046  * Compute IPv6 extension header length.
3047  */
3048 int
3049 ip6_optlen(struct inpcb *in6p)
3050 {
3051 	int len;
3052 
3053 	if (!in6p->in6p_outputopts)
3054 		return 0;
3055 
3056 	len = 0;
3057 #define elen(x) \
3058     (((struct ip6_ext *)(x)) ? (((struct ip6_ext *)(x))->ip6e_len + 1) << 3 : 0)
3059 
3060 	len += elen(in6p->in6p_outputopts->ip6po_hbh);
3061 	if (in6p->in6p_outputopts->ip6po_rthdr)
3062 		/* dest1 is valid with rthdr only */
3063 		len += elen(in6p->in6p_outputopts->ip6po_dest1);
3064 	len += elen(in6p->in6p_outputopts->ip6po_rthdr);
3065 	len += elen(in6p->in6p_outputopts->ip6po_dest2);
3066 	return len;
3067 #undef elen
3068 }
3069