xref: /netbsd-src/sys/netinet6/ip6_output.c (revision ce2c90c7c172d95d2402a5b3d96d8f8e6d138a21)
1 /*	$NetBSD: ip6_output.c,v 1.103 2006/10/12 01:32:39 christos Exp $	*/
2 /*	$KAME: ip6_output.c,v 1.172 2001/03/25 09:55:56 itojun Exp $	*/
3 
4 /*
5  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the name of the project nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 /*
34  * Copyright (c) 1982, 1986, 1988, 1990, 1993
35  *	The Regents of the University of California.  All rights reserved.
36  *
37  * Redistribution and use in source and binary forms, with or without
38  * modification, are permitted provided that the following conditions
39  * are met:
40  * 1. Redistributions of source code must retain the above copyright
41  *    notice, this list of conditions and the following disclaimer.
42  * 2. Redistributions in binary form must reproduce the above copyright
43  *    notice, this list of conditions and the following disclaimer in the
44  *    documentation and/or other materials provided with the distribution.
45  * 3. Neither the name of the University nor the names of its contributors
46  *    may be used to endorse or promote products derived from this software
47  *    without specific prior written permission.
48  *
49  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
50  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
51  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
52  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
53  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
54  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
55  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
56  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
57  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
58  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
59  * SUCH DAMAGE.
60  *
61  *	@(#)ip_output.c	8.3 (Berkeley) 1/21/94
62  */
63 
64 #include <sys/cdefs.h>
65 __KERNEL_RCSID(0, "$NetBSD: ip6_output.c,v 1.103 2006/10/12 01:32:39 christos Exp $");
66 
67 #include "opt_inet.h"
68 #include "opt_inet6.h"
69 #include "opt_ipsec.h"
70 #include "opt_pfil_hooks.h"
71 
72 #include <sys/param.h>
73 #include <sys/malloc.h>
74 #include <sys/mbuf.h>
75 #include <sys/errno.h>
76 #include <sys/protosw.h>
77 #include <sys/socket.h>
78 #include <sys/socketvar.h>
79 #include <sys/systm.h>
80 #include <sys/proc.h>
81 #include <sys/kauth.h>
82 
83 #include <net/if.h>
84 #include <net/route.h>
85 #ifdef PFIL_HOOKS
86 #include <net/pfil.h>
87 #endif
88 
89 #include <netinet/in.h>
90 #include <netinet/in_var.h>
91 #include <netinet/ip6.h>
92 #include <netinet/icmp6.h>
93 #include <netinet/in_offload.h>
94 #include <netinet6/ip6_var.h>
95 #include <netinet6/in6_pcb.h>
96 #include <netinet6/nd6.h>
97 #include <netinet6/ip6protosw.h>
98 #include <netinet6/scope6_var.h>
99 
100 #ifdef IPSEC
101 #include <netinet6/ipsec.h>
102 #include <netkey/key.h>
103 #endif /* IPSEC */
104 
105 #include <net/net_osdep.h>
106 
107 #ifdef PFIL_HOOKS
108 extern struct pfil_head inet6_pfil_hook;	/* XXX */
109 #endif
110 
111 struct ip6_exthdrs {
112 	struct mbuf *ip6e_ip6;
113 	struct mbuf *ip6e_hbh;
114 	struct mbuf *ip6e_dest1;
115 	struct mbuf *ip6e_rthdr;
116 	struct mbuf *ip6e_dest2;
117 };
118 
119 static int ip6_pcbopt __P((int, u_char *, int, struct ip6_pktopts **,
120 	int, int));
121 static int ip6_getpcbopt __P((struct ip6_pktopts *, int, struct mbuf **));
122 static int ip6_setpktopt __P((int, u_char *, int, struct ip6_pktopts *, int,
123 	int, int, int));
124 static int ip6_setmoptions __P((int, struct ip6_moptions **, struct mbuf *));
125 static int ip6_getmoptions __P((int, struct ip6_moptions *, struct mbuf **));
126 static int ip6_copyexthdr __P((struct mbuf **, caddr_t, int));
127 static int ip6_insertfraghdr __P((struct mbuf *, struct mbuf *, int,
128 	struct ip6_frag **));
129 static int ip6_insert_jumboopt __P((struct ip6_exthdrs *, u_int32_t));
130 static int ip6_splithdr __P((struct mbuf *, struct ip6_exthdrs *));
131 static int ip6_getpmtu __P((struct route_in6 *, struct route_in6 *,
132 	struct ifnet *, struct in6_addr *, u_long *, int *));
133 static int copypktopts __P((struct ip6_pktopts *, struct ip6_pktopts *, int));
134 
135 #ifdef RFC2292
136 static int ip6_pcbopts __P((struct ip6_pktopts **, struct mbuf *,
137 	struct socket *));
138 #endif
139 
140 #define	IN6_NEED_CHECKSUM(ifp, csum_flags) \
141 	(__predict_true(((ifp)->if_flags & IFF_LOOPBACK) == 0 || \
142 	(((csum_flags) & M_CSUM_UDPv6) != 0 && udp_do_loopback_cksum) || \
143 	(((csum_flags) & M_CSUM_TCPv6) != 0 && tcp_do_loopback_cksum)))
144 
145 /*
146  * IP6 output. The packet in mbuf chain m contains a skeletal IP6
147  * header (with pri, len, nxt, hlim, src, dst).
148  * This function may modify ver and hlim only.
149  * The mbuf chain containing the packet will be freed.
150  * The mbuf opt, if present, will not be freed.
151  *
152  * type of "mtu": rt_rmx.rmx_mtu is u_long, ifnet.ifr_mtu is int, and
153  * nd_ifinfo.linkmtu is u_int32_t.  so we use u_long to hold largest one,
154  * which is rt_rmx.rmx_mtu.
155  */
156 int
157 ip6_output(
158     struct mbuf *m0,
159     struct ip6_pktopts *opt,
160     struct route_in6 *ro,
161     int flags,
162     struct ip6_moptions *im6o,
163     struct socket *so __unused,
164     struct ifnet **ifpp		/* XXX: just for statistics */
165 )
166 {
167 	struct ip6_hdr *ip6, *mhip6;
168 	struct ifnet *ifp, *origifp;
169 	struct mbuf *m = m0;
170 	int hlen, tlen, len, off;
171 	struct route_in6 ip6route;
172 	struct rtentry *rt = NULL;
173 	struct sockaddr_in6 *dst, src_sa, dst_sa;
174 	int error = 0;
175 	struct in6_ifaddr *ia = NULL;
176 	u_long mtu;
177 	int alwaysfrag, dontfrag;
178 	u_int32_t optlen = 0, plen = 0, unfragpartlen = 0;
179 	struct ip6_exthdrs exthdrs;
180 	struct in6_addr finaldst, src0, dst0;
181 	u_int32_t zone;
182 	struct route_in6 *ro_pmtu = NULL;
183 	int hdrsplit = 0;
184 	int needipsec = 0;
185 #ifdef IPSEC
186 	int needipsectun = 0;
187 	struct secpolicy *sp = NULL;
188 
189 	ip6 = mtod(m, struct ip6_hdr *);
190 #endif /* IPSEC */
191 
192 #ifdef  DIAGNOSTIC
193 	if ((m->m_flags & M_PKTHDR) == 0)
194 		panic("ip6_output: no HDR");
195 
196 	if ((m->m_pkthdr.csum_flags &
197 	    (M_CSUM_TCPv4|M_CSUM_UDPv4|M_CSUM_TSOv4)) != 0) {
198 		panic("ip6_output: IPv4 checksum offload flags: %d",
199 		    m->m_pkthdr.csum_flags);
200 	}
201 
202 	if ((m->m_pkthdr.csum_flags & (M_CSUM_TCPv6|M_CSUM_UDPv6)) ==
203 	    (M_CSUM_TCPv6|M_CSUM_UDPv6)) {
204 		panic("ip6_output: conflicting checksum offload flags: %d",
205 		    m->m_pkthdr.csum_flags);
206 	}
207 #endif
208 
209 	M_CSUM_DATA_IPv6_HL_SET(m->m_pkthdr.csum_data, sizeof(struct ip6_hdr));
210 
211 #define MAKE_EXTHDR(hp, mp)						\
212     do {								\
213 	if (hp) {							\
214 		struct ip6_ext *eh = (struct ip6_ext *)(hp);		\
215 		error = ip6_copyexthdr((mp), (caddr_t)(hp), 		\
216 		    ((eh)->ip6e_len + 1) << 3);				\
217 		if (error)						\
218 			goto freehdrs;					\
219 	}								\
220     } while (/*CONSTCOND*/ 0)
221 
222 	bzero(&exthdrs, sizeof(exthdrs));
223 	if (opt) {
224 		/* Hop-by-Hop options header */
225 		MAKE_EXTHDR(opt->ip6po_hbh, &exthdrs.ip6e_hbh);
226 		/* Destination options header(1st part) */
227 		MAKE_EXTHDR(opt->ip6po_dest1, &exthdrs.ip6e_dest1);
228 		/* Routing header */
229 		MAKE_EXTHDR(opt->ip6po_rthdr, &exthdrs.ip6e_rthdr);
230 		/* Destination options header(2nd part) */
231 		MAKE_EXTHDR(opt->ip6po_dest2, &exthdrs.ip6e_dest2);
232 	}
233 
234 #ifdef IPSEC
235 	if ((flags & IPV6_FORWARDING) != 0) {
236 		needipsec = 0;
237 		goto skippolicycheck;
238 	}
239 
240 	/* get a security policy for this packet */
241 	if (so == NULL)
242 		sp = ipsec6_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, 0, &error);
243 	else {
244 		if (IPSEC_PCB_SKIP_IPSEC(sotoinpcb_hdr(so)->inph_sp,
245 					 IPSEC_DIR_OUTBOUND)) {
246 			needipsec = 0;
247 			goto skippolicycheck;
248 		}
249 		sp = ipsec6_getpolicybysock(m, IPSEC_DIR_OUTBOUND, so, &error);
250 	}
251 
252 	if (sp == NULL) {
253 		ipsec6stat.out_inval++;
254 		goto freehdrs;
255 	}
256 
257 	error = 0;
258 
259 	/* check policy */
260 	switch (sp->policy) {
261 	case IPSEC_POLICY_DISCARD:
262 		/*
263 		 * This packet is just discarded.
264 		 */
265 		ipsec6stat.out_polvio++;
266 		goto freehdrs;
267 
268 	case IPSEC_POLICY_BYPASS:
269 	case IPSEC_POLICY_NONE:
270 		/* no need to do IPsec. */
271 		needipsec = 0;
272 		break;
273 
274 	case IPSEC_POLICY_IPSEC:
275 		if (sp->req == NULL) {
276 			/* XXX should be panic ? */
277 			printf("ip6_output: No IPsec request specified.\n");
278 			error = EINVAL;
279 			goto freehdrs;
280 		}
281 		needipsec = 1;
282 		break;
283 
284 	case IPSEC_POLICY_ENTRUST:
285 	default:
286 		printf("ip6_output: Invalid policy found. %d\n", sp->policy);
287 	}
288 
289   skippolicycheck:;
290 #endif /* IPSEC */
291 
292 	if (needipsec &&
293 	    (m->m_pkthdr.csum_flags & (M_CSUM_UDPv6|M_CSUM_TCPv6)) != 0) {
294 		in6_delayed_cksum(m);
295 		m->m_pkthdr.csum_flags &= ~(M_CSUM_UDPv6|M_CSUM_TCPv6);
296 	}
297 
298 	/*
299 	 * Calculate the total length of the extension header chain.
300 	 * Keep the length of the unfragmentable part for fragmentation.
301 	 */
302 	optlen = 0;
303 	if (exthdrs.ip6e_hbh) optlen += exthdrs.ip6e_hbh->m_len;
304 	if (exthdrs.ip6e_dest1) optlen += exthdrs.ip6e_dest1->m_len;
305 	if (exthdrs.ip6e_rthdr) optlen += exthdrs.ip6e_rthdr->m_len;
306 	unfragpartlen = optlen + sizeof(struct ip6_hdr);
307 	/* NOTE: we don't add AH/ESP length here. do that later. */
308 	if (exthdrs.ip6e_dest2) optlen += exthdrs.ip6e_dest2->m_len;
309 
310 	/*
311 	 * If we need IPsec, or there is at least one extension header,
312 	 * separate IP6 header from the payload.
313 	 */
314 	if ((needipsec || optlen) && !hdrsplit) {
315 		if ((error = ip6_splithdr(m, &exthdrs)) != 0) {
316 			m = NULL;
317 			goto freehdrs;
318 		}
319 		m = exthdrs.ip6e_ip6;
320 		hdrsplit++;
321 	}
322 
323 	/* adjust pointer */
324 	ip6 = mtod(m, struct ip6_hdr *);
325 
326 	/* adjust mbuf packet header length */
327 	m->m_pkthdr.len += optlen;
328 	plen = m->m_pkthdr.len - sizeof(*ip6);
329 
330 	/* If this is a jumbo payload, insert a jumbo payload option. */
331 	if (plen > IPV6_MAXPACKET) {
332 		if (!hdrsplit) {
333 			if ((error = ip6_splithdr(m, &exthdrs)) != 0) {
334 				m = NULL;
335 				goto freehdrs;
336 			}
337 			m = exthdrs.ip6e_ip6;
338 			hdrsplit++;
339 		}
340 		/* adjust pointer */
341 		ip6 = mtod(m, struct ip6_hdr *);
342 		if ((error = ip6_insert_jumboopt(&exthdrs, plen)) != 0)
343 			goto freehdrs;
344 		optlen += 8; /* XXX JUMBOOPTLEN */
345 		ip6->ip6_plen = 0;
346 	} else
347 		ip6->ip6_plen = htons(plen);
348 
349 	/*
350 	 * Concatenate headers and fill in next header fields.
351 	 * Here we have, on "m"
352 	 *	IPv6 payload
353 	 * and we insert headers accordingly.  Finally, we should be getting:
354 	 *	IPv6 hbh dest1 rthdr ah* [esp* dest2 payload]
355 	 *
356 	 * during the header composing process, "m" points to IPv6 header.
357 	 * "mprev" points to an extension header prior to esp.
358 	 */
359 	{
360 		u_char *nexthdrp = &ip6->ip6_nxt;
361 		struct mbuf *mprev = m;
362 
363 		/*
364 		 * we treat dest2 specially.  this makes IPsec processing
365 		 * much easier.  the goal here is to make mprev point the
366 		 * mbuf prior to dest2.
367 		 *
368 		 * result: IPv6 dest2 payload
369 		 * m and mprev will point to IPv6 header.
370 		 */
371 		if (exthdrs.ip6e_dest2) {
372 			if (!hdrsplit)
373 				panic("assumption failed: hdr not split");
374 			exthdrs.ip6e_dest2->m_next = m->m_next;
375 			m->m_next = exthdrs.ip6e_dest2;
376 			*mtod(exthdrs.ip6e_dest2, u_char *) = ip6->ip6_nxt;
377 			ip6->ip6_nxt = IPPROTO_DSTOPTS;
378 		}
379 
380 #define MAKE_CHAIN(m, mp, p, i)\
381     do {\
382 	if (m) {\
383 		if (!hdrsplit) \
384 			panic("assumption failed: hdr not split"); \
385 		*mtod((m), u_char *) = *(p);\
386 		*(p) = (i);\
387 		p = mtod((m), u_char *);\
388 		(m)->m_next = (mp)->m_next;\
389 		(mp)->m_next = (m);\
390 		(mp) = (m);\
391 	}\
392     } while (/*CONSTCOND*/ 0)
393 		/*
394 		 * result: IPv6 hbh dest1 rthdr dest2 payload
395 		 * m will point to IPv6 header.  mprev will point to the
396 		 * extension header prior to dest2 (rthdr in the above case).
397 		 */
398 		MAKE_CHAIN(exthdrs.ip6e_hbh, mprev, nexthdrp, IPPROTO_HOPOPTS);
399 		MAKE_CHAIN(exthdrs.ip6e_dest1, mprev, nexthdrp,
400 		    IPPROTO_DSTOPTS);
401 		MAKE_CHAIN(exthdrs.ip6e_rthdr, mprev, nexthdrp,
402 		    IPPROTO_ROUTING);
403 
404 		M_CSUM_DATA_IPv6_HL_SET(m->m_pkthdr.csum_data,
405 		    sizeof(struct ip6_hdr) + optlen);
406 
407 #ifdef IPSEC
408 		if (!needipsec)
409 			goto skip_ipsec2;
410 
411 		/*
412 		 * pointers after IPsec headers are not valid any more.
413 		 * other pointers need a great care too.
414 		 * (IPsec routines should not mangle mbufs prior to AH/ESP)
415 		 */
416 		exthdrs.ip6e_dest2 = NULL;
417 
418 	    {
419 		struct ip6_rthdr *rh = NULL;
420 		int segleft_org = 0;
421 		struct ipsec_output_state state;
422 
423 		if (exthdrs.ip6e_rthdr) {
424 			rh = mtod(exthdrs.ip6e_rthdr, struct ip6_rthdr *);
425 			segleft_org = rh->ip6r_segleft;
426 			rh->ip6r_segleft = 0;
427 		}
428 
429 		bzero(&state, sizeof(state));
430 		state.m = m;
431 		error = ipsec6_output_trans(&state, nexthdrp, mprev, sp, flags,
432 		    &needipsectun);
433 		m = state.m;
434 		if (error) {
435 			/* mbuf is already reclaimed in ipsec6_output_trans. */
436 			m = NULL;
437 			switch (error) {
438 			case EHOSTUNREACH:
439 			case ENETUNREACH:
440 			case EMSGSIZE:
441 			case ENOBUFS:
442 			case ENOMEM:
443 				break;
444 			default:
445 				printf("ip6_output (ipsec): error code %d\n", error);
446 				/* FALLTHROUGH */
447 			case ENOENT:
448 				/* don't show these error codes to the user */
449 				error = 0;
450 				break;
451 			}
452 			goto bad;
453 		}
454 		if (exthdrs.ip6e_rthdr) {
455 			/* ah6_output doesn't modify mbuf chain */
456 			rh->ip6r_segleft = segleft_org;
457 		}
458 	    }
459 skip_ipsec2:;
460 #endif
461 	}
462 
463 	/*
464 	 * If there is a routing header, replace destination address field
465 	 * with the first hop of the routing header.
466 	 */
467 	if (exthdrs.ip6e_rthdr) {
468 		struct ip6_rthdr *rh;
469 		struct ip6_rthdr0 *rh0;
470 		struct in6_addr *addr;
471 		struct sockaddr_in6 sa;
472 
473 		rh = (struct ip6_rthdr *)(mtod(exthdrs.ip6e_rthdr,
474 		    struct ip6_rthdr *));
475 		finaldst = ip6->ip6_dst;
476 		switch (rh->ip6r_type) {
477 		case IPV6_RTHDR_TYPE_0:
478 			 rh0 = (struct ip6_rthdr0 *)rh;
479 			 addr = (struct in6_addr *)(rh0 + 1);
480 
481 			 /*
482 			  * construct a sockaddr_in6 form of
483 			  * the first hop.
484 			  *
485 			  * XXX: we may not have enough
486 			  * information about its scope zone;
487 			  * there is no standard API to pass
488 			  * the information from the
489 			  * application.
490 			  */
491 			 bzero(&sa, sizeof(sa));
492 			 sa.sin6_family = AF_INET6;
493 			 sa.sin6_len = sizeof(sa);
494 			 sa.sin6_addr = addr[0];
495 			 if ((error = sa6_embedscope(&sa,
496 			     ip6_use_defzone)) != 0) {
497 				 goto bad;
498 			 }
499 			 ip6->ip6_dst = sa.sin6_addr;
500 			 (void)memmove(&addr[0], &addr[1],
501 			     sizeof(struct in6_addr) *
502 			     (rh0->ip6r0_segleft - 1));
503 			 addr[rh0->ip6r0_segleft - 1] = finaldst;
504 			 /* XXX */
505 			 in6_clearscope(addr + rh0->ip6r0_segleft - 1);
506 			 break;
507 		default:	/* is it possible? */
508 			 error = EINVAL;
509 			 goto bad;
510 		}
511 	}
512 
513 	/* Source address validation */
514 	if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) &&
515 	    (flags & IPV6_UNSPECSRC) == 0) {
516 		error = EOPNOTSUPP;
517 		ip6stat.ip6s_badscope++;
518 		goto bad;
519 	}
520 	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_src)) {
521 		error = EOPNOTSUPP;
522 		ip6stat.ip6s_badscope++;
523 		goto bad;
524 	}
525 
526 	ip6stat.ip6s_localout++;
527 
528 	/*
529 	 * Route packet.
530 	 */
531 	/* initialize cached route */
532 	if (ro == 0) {
533 		ro = &ip6route;
534 		bzero((caddr_t)ro, sizeof(*ro));
535 	}
536 	ro_pmtu = ro;
537 	if (opt && opt->ip6po_rthdr)
538 		ro = &opt->ip6po_route;
539 	dst = (struct sockaddr_in6 *)&ro->ro_dst;
540 
541  	/*
542 	 * if specified, try to fill in the traffic class field.
543 	 * do not override if a non-zero value is already set.
544 	 * we check the diffserv field and the ecn field separately.
545 	 */
546 	if (opt && opt->ip6po_tclass >= 0) {
547 		int mask = 0;
548 
549 		if ((ip6->ip6_flow & htonl(0xfc << 20)) == 0)
550 			mask |= 0xfc;
551 		if ((ip6->ip6_flow & htonl(0x03 << 20)) == 0)
552 			mask |= 0x03;
553 		if (mask != 0)
554 			ip6->ip6_flow |= htonl((opt->ip6po_tclass & mask) << 20);
555 	}
556 
557 	/* fill in or override the hop limit field, if necessary. */
558 	if (opt && opt->ip6po_hlim != -1)
559 		ip6->ip6_hlim = opt->ip6po_hlim & 0xff;
560 	else if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
561 		if (im6o != NULL)
562 			ip6->ip6_hlim = im6o->im6o_multicast_hlim;
563 		else
564 			ip6->ip6_hlim = ip6_defmcasthlim;
565 	}
566 
567 #ifdef IPSEC
568 	if (needipsec && needipsectun) {
569 		struct ipsec_output_state state;
570 
571 		/*
572 		 * All the extension headers will become inaccessible
573 		 * (since they can be encrypted).
574 		 * Don't panic, we need no more updates to extension headers
575 		 * on inner IPv6 packet (since they are now encapsulated).
576 		 *
577 		 * IPv6 [ESP|AH] IPv6 [extension headers] payload
578 		 */
579 		bzero(&exthdrs, sizeof(exthdrs));
580 		exthdrs.ip6e_ip6 = m;
581 
582 		bzero(&state, sizeof(state));
583 		state.m = m;
584 		state.ro = (struct route *)ro;
585 		state.dst = (struct sockaddr *)dst;
586 
587 		error = ipsec6_output_tunnel(&state, sp, flags);
588 
589 		m = state.m;
590 		ro_pmtu = ro = (struct route_in6 *)state.ro;
591 		dst = (struct sockaddr_in6 *)state.dst;
592 		if (error) {
593 			/* mbuf is already reclaimed in ipsec6_output_tunnel. */
594 			m0 = m = NULL;
595 			m = NULL;
596 			switch (error) {
597 			case EHOSTUNREACH:
598 			case ENETUNREACH:
599 			case EMSGSIZE:
600 			case ENOBUFS:
601 			case ENOMEM:
602 				break;
603 			default:
604 				printf("ip6_output (ipsec): error code %d\n", error);
605 				/* FALLTHROUGH */
606 			case ENOENT:
607 				/* don't show these error codes to the user */
608 				error = 0;
609 				break;
610 			}
611 			goto bad;
612 		}
613 
614 		exthdrs.ip6e_ip6 = m;
615 	}
616 #endif /* IPSEC */
617 
618 	/* adjust pointer */
619 	ip6 = mtod(m, struct ip6_hdr *);
620 
621 	bzero(&dst_sa, sizeof(dst_sa));
622 	dst_sa.sin6_family = AF_INET6;
623 	dst_sa.sin6_len = sizeof(dst_sa);
624 	dst_sa.sin6_addr = ip6->ip6_dst;
625 	if ((error = in6_selectroute(&dst_sa, opt, im6o, ro, &ifp, &rt, 0))
626 	    != 0) {
627 		switch (error) {
628 		case EHOSTUNREACH:
629 			ip6stat.ip6s_noroute++;
630 			break;
631 		case EADDRNOTAVAIL:
632 		default:
633 			break; /* XXX statistics? */
634 		}
635 		if (ifp != NULL)
636 			in6_ifstat_inc(ifp, ifs6_out_discard);
637 		goto bad;
638 	}
639 	if (rt == NULL) {
640 		/*
641 		 * If in6_selectroute() does not return a route entry,
642 		 * dst may not have been updated.
643 		 */
644 		*dst = dst_sa;	/* XXX */
645 	}
646 
647 	/*
648 	 * then rt (for unicast) and ifp must be non-NULL valid values.
649 	 */
650 	if ((flags & IPV6_FORWARDING) == 0) {
651 		/* XXX: the FORWARDING flag can be set for mrouting. */
652 		in6_ifstat_inc(ifp, ifs6_out_request);
653 	}
654 	if (rt != NULL) {
655 		ia = (struct in6_ifaddr *)(rt->rt_ifa);
656 		rt->rt_use++;
657 	}
658 
659 	/*
660 	 * The outgoing interface must be in the zone of source and
661 	 * destination addresses.  We should use ia_ifp to support the
662 	 * case of sending packets to an address of our own.
663 	 */
664 	if (ia != NULL && ia->ia_ifp)
665 		origifp = ia->ia_ifp;
666 	else
667 		origifp = ifp;
668 
669 	src0 = ip6->ip6_src;
670 	if (in6_setscope(&src0, origifp, &zone))
671 		goto badscope;
672 	bzero(&src_sa, sizeof(src_sa));
673 	src_sa.sin6_family = AF_INET6;
674 	src_sa.sin6_len = sizeof(src_sa);
675 	src_sa.sin6_addr = ip6->ip6_src;
676 	if (sa6_recoverscope(&src_sa) || zone != src_sa.sin6_scope_id)
677 		goto badscope;
678 
679 	dst0 = ip6->ip6_dst;
680 	if (in6_setscope(&dst0, origifp, &zone))
681 		goto badscope;
682 	/* re-initialize to be sure */
683 	bzero(&dst_sa, sizeof(dst_sa));
684 	dst_sa.sin6_family = AF_INET6;
685 	dst_sa.sin6_len = sizeof(dst_sa);
686 	dst_sa.sin6_addr = ip6->ip6_dst;
687 	if (sa6_recoverscope(&dst_sa) || zone != dst_sa.sin6_scope_id)
688 		goto badscope;
689 
690 	/* scope check is done. */
691 	goto routefound;
692 
693   badscope:
694 	ip6stat.ip6s_badscope++;
695 	in6_ifstat_inc(origifp, ifs6_out_discard);
696 	if (error == 0)
697 		error = EHOSTUNREACH; /* XXX */
698 	goto bad;
699 
700   routefound:
701 	if (rt && !IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
702 		if (opt && opt->ip6po_nextroute.ro_rt) {
703 			/*
704 			 * The nexthop is explicitly specified by the
705 			 * application.  We assume the next hop is an IPv6
706 			 * address.
707 			 */
708 			dst = (struct sockaddr_in6 *)opt->ip6po_nexthop;
709 		} else if ((rt->rt_flags & RTF_GATEWAY))
710 			dst = (struct sockaddr_in6 *)rt->rt_gateway;
711 	}
712 
713 	/*
714 	 * XXXXXX: original code follows:
715 	 */
716 	if (!IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst))
717 		m->m_flags &= ~(M_BCAST | M_MCAST);	/* just in case */
718 	else {
719 		struct	in6_multi *in6m;
720 
721 		m->m_flags = (m->m_flags & ~M_BCAST) | M_MCAST;
722 
723 		in6_ifstat_inc(ifp, ifs6_out_mcast);
724 
725 		/*
726 		 * Confirm that the outgoing interface supports multicast.
727 		 */
728 		if (!(ifp->if_flags & IFF_MULTICAST)) {
729 			ip6stat.ip6s_noroute++;
730 			in6_ifstat_inc(ifp, ifs6_out_discard);
731 			error = ENETUNREACH;
732 			goto bad;
733 		}
734 
735 		IN6_LOOKUP_MULTI(ip6->ip6_dst, ifp, in6m);
736 		if (in6m != NULL &&
737 		   (im6o == NULL || im6o->im6o_multicast_loop)) {
738 			/*
739 			 * If we belong to the destination multicast group
740 			 * on the outgoing interface, and the caller did not
741 			 * forbid loopback, loop back a copy.
742 			 */
743 			ip6_mloopback(ifp, m, dst);
744 		} else {
745 			/*
746 			 * If we are acting as a multicast router, perform
747 			 * multicast forwarding as if the packet had just
748 			 * arrived on the interface to which we are about
749 			 * to send.  The multicast forwarding function
750 			 * recursively calls this function, using the
751 			 * IPV6_FORWARDING flag to prevent infinite recursion.
752 			 *
753 			 * Multicasts that are looped back by ip6_mloopback(),
754 			 * above, will be forwarded by the ip6_input() routine,
755 			 * if necessary.
756 			 */
757 			if (ip6_mrouter && (flags & IPV6_FORWARDING) == 0) {
758 				if (ip6_mforward(ip6, ifp, m) != 0) {
759 					m_freem(m);
760 					goto done;
761 				}
762 			}
763 		}
764 		/*
765 		 * Multicasts with a hoplimit of zero may be looped back,
766 		 * above, but must not be transmitted on a network.
767 		 * Also, multicasts addressed to the loopback interface
768 		 * are not sent -- the above call to ip6_mloopback() will
769 		 * loop back a copy if this host actually belongs to the
770 		 * destination group on the loopback interface.
771 		 */
772 		if (ip6->ip6_hlim == 0 || (ifp->if_flags & IFF_LOOPBACK) ||
773 		    IN6_IS_ADDR_MC_INTFACELOCAL(&ip6->ip6_dst)) {
774 			m_freem(m);
775 			goto done;
776 		}
777 	}
778 
779 	/*
780 	 * Fill the outgoing inteface to tell the upper layer
781 	 * to increment per-interface statistics.
782 	 */
783 	if (ifpp)
784 		*ifpp = ifp;
785 
786 	/* Determine path MTU. */
787 	if ((error = ip6_getpmtu(ro_pmtu, ro, ifp, &finaldst, &mtu,
788 	    &alwaysfrag)) != 0)
789 		goto bad;
790 #ifdef IPSEC
791 	if (needipsectun)
792 		mtu = IPV6_MMTU;
793 #endif
794 
795 	/*
796 	 * The caller of this function may specify to use the minimum MTU
797 	 * in some cases.
798 	 * An advanced API option (IPV6_USE_MIN_MTU) can also override MTU
799 	 * setting.  The logic is a bit complicated; by default, unicast
800 	 * packets will follow path MTU while multicast packets will be sent at
801 	 * the minimum MTU.  If IP6PO_MINMTU_ALL is specified, all packets
802 	 * including unicast ones will be sent at the minimum MTU.  Multicast
803 	 * packets will always be sent at the minimum MTU unless
804 	 * IP6PO_MINMTU_DISABLE is explicitly specified.
805 	 * See RFC 3542 for more details.
806 	 */
807 	if (mtu > IPV6_MMTU) {
808 		if ((flags & IPV6_MINMTU))
809 			mtu = IPV6_MMTU;
810 		else if (opt && opt->ip6po_minmtu == IP6PO_MINMTU_ALL)
811 			mtu = IPV6_MMTU;
812 		else if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) &&
813 			 (opt == NULL ||
814 			  opt->ip6po_minmtu != IP6PO_MINMTU_DISABLE)) {
815 			mtu = IPV6_MMTU;
816 		}
817 	}
818 
819 	/*
820 	 * clear embedded scope identifiers if necessary.
821 	 * in6_clearscope will touch the addresses only when necessary.
822 	 */
823 	in6_clearscope(&ip6->ip6_src);
824 	in6_clearscope(&ip6->ip6_dst);
825 
826 	/*
827 	 * If the outgoing packet contains a hop-by-hop options header,
828 	 * it must be examined and processed even by the source node.
829 	 * (RFC 2460, section 4.)
830 	 */
831 	if (exthdrs.ip6e_hbh) {
832 		struct ip6_hbh *hbh = mtod(exthdrs.ip6e_hbh, struct ip6_hbh *);
833 		u_int32_t dummy1; /* XXX unused */
834 		u_int32_t dummy2; /* XXX unused */
835 
836 		/*
837 		 *  XXX: if we have to send an ICMPv6 error to the sender,
838 		 *       we need the M_LOOP flag since icmp6_error() expects
839 		 *       the IPv6 and the hop-by-hop options header are
840 		 *       continuous unless the flag is set.
841 		 */
842 		m->m_flags |= M_LOOP;
843 		m->m_pkthdr.rcvif = ifp;
844 		if (ip6_process_hopopts(m, (u_int8_t *)(hbh + 1),
845 		    ((hbh->ip6h_len + 1) << 3) - sizeof(struct ip6_hbh),
846 		    &dummy1, &dummy2) < 0) {
847 			/* m was already freed at this point */
848 			error = EINVAL;/* better error? */
849 			goto done;
850 		}
851 		m->m_flags &= ~M_LOOP; /* XXX */
852 		m->m_pkthdr.rcvif = NULL;
853 	}
854 
855 #ifdef PFIL_HOOKS
856 	/*
857 	 * Run through list of hooks for output packets.
858 	 */
859 	if ((error = pfil_run_hooks(&inet6_pfil_hook, &m, ifp, PFIL_OUT)) != 0)
860 		goto done;
861 	if (m == NULL)
862 		goto done;
863 	ip6 = mtod(m, struct ip6_hdr *);
864 #endif /* PFIL_HOOKS */
865 	/*
866 	 * Send the packet to the outgoing interface.
867 	 * If necessary, do IPv6 fragmentation before sending.
868 	 *
869 	 * the logic here is rather complex:
870 	 * 1: normal case (dontfrag == 0, alwaysfrag == 0)
871 	 * 1-a:	send as is if tlen <= path mtu
872 	 * 1-b:	fragment if tlen > path mtu
873 	 *
874 	 * 2: if user asks us not to fragment (dontfrag == 1)
875 	 * 2-a:	send as is if tlen <= interface mtu
876 	 * 2-b:	error if tlen > interface mtu
877 	 *
878 	 * 3: if we always need to attach fragment header (alwaysfrag == 1)
879 	 *	always fragment
880 	 *
881 	 * 4: if dontfrag == 1 && alwaysfrag == 1
882 	 *	error, as we cannot handle this conflicting request
883 	 */
884 	tlen = m->m_pkthdr.len;
885 
886 	if (opt && (opt->ip6po_flags & IP6PO_DONTFRAG))
887 		dontfrag = 1;
888 	else
889 		dontfrag = 0;
890 
891 	if (dontfrag && alwaysfrag) {	/* case 4 */
892 		/* conflicting request - can't transmit */
893 		error = EMSGSIZE;
894 		goto bad;
895 	}
896 	if (dontfrag && tlen > IN6_LINKMTU(ifp)) {	/* case 2-b */
897 		/*
898 		 * Even if the DONTFRAG option is specified, we cannot send the
899 		 * packet when the data length is larger than the MTU of the
900 		 * outgoing interface.
901 		 * Notify the error by sending IPV6_PATHMTU ancillary data as
902 		 * well as returning an error code (the latter is not described
903 		 * in the API spec.)
904 		 */
905 		u_int32_t mtu32;
906 		struct ip6ctlparam ip6cp;
907 
908 		mtu32 = (u_int32_t)mtu;
909 		bzero(&ip6cp, sizeof(ip6cp));
910 		ip6cp.ip6c_cmdarg = (void *)&mtu32;
911 		pfctlinput2(PRC_MSGSIZE, (struct sockaddr *)&ro_pmtu->ro_dst,
912 		    (void *)&ip6cp);
913 
914 		error = EMSGSIZE;
915 		goto bad;
916 	}
917 
918 	/*
919 	 * transmit packet without fragmentation
920 	 */
921 	if (dontfrag || (!alwaysfrag && tlen <= mtu)) {	/* case 1-a and 2-a */
922 		struct in6_ifaddr *ia6;
923 		int sw_csum;
924 
925 		ip6 = mtod(m, struct ip6_hdr *);
926 		ia6 = in6_ifawithifp(ifp, &ip6->ip6_src);
927 		if (ia6) {
928 			/* Record statistics for this interface address. */
929 			ia6->ia_ifa.ifa_data.ifad_outbytes += m->m_pkthdr.len;
930 		}
931 #ifdef IPSEC
932 		/* clean ipsec history once it goes out of the node */
933 		ipsec_delaux(m);
934 #endif
935 
936 		sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_csum_flags_tx;
937 		if ((sw_csum & (M_CSUM_UDPv6|M_CSUM_TCPv6)) != 0) {
938 			if (IN6_NEED_CHECKSUM(ifp,
939 			    sw_csum & (M_CSUM_UDPv6|M_CSUM_TCPv6))) {
940 				in6_delayed_cksum(m);
941 			}
942 			m->m_pkthdr.csum_flags &= ~(M_CSUM_UDPv6|M_CSUM_TCPv6);
943 		}
944 
945 		error = nd6_output(ifp, origifp, m, dst, rt);
946 		goto done;
947 	}
948 
949 	/*
950 	 * try to fragment the packet.  case 1-b and 3
951 	 */
952 	if (mtu < IPV6_MMTU) {
953 		/* path MTU cannot be less than IPV6_MMTU */
954 		error = EMSGSIZE;
955 		in6_ifstat_inc(ifp, ifs6_out_fragfail);
956 		goto bad;
957 	} else if (ip6->ip6_plen == 0) {
958 		/* jumbo payload cannot be fragmented */
959 		error = EMSGSIZE;
960 		in6_ifstat_inc(ifp, ifs6_out_fragfail);
961 		goto bad;
962 	} else {
963 		struct mbuf **mnext, *m_frgpart;
964 		struct ip6_frag *ip6f;
965 		u_int32_t id = htonl(ip6_randomid());
966 		u_char nextproto;
967 #if 0				/* see below */
968 		struct ip6ctlparam ip6cp;
969 		u_int32_t mtu32;
970 #endif
971 
972 		/*
973 		 * Too large for the destination or interface;
974 		 * fragment if possible.
975 		 * Must be able to put at least 8 bytes per fragment.
976 		 */
977 		hlen = unfragpartlen;
978 		if (mtu > IPV6_MAXPACKET)
979 			mtu = IPV6_MAXPACKET;
980 
981 #if 0
982 		/*
983 		 * It is believed this code is a leftover from the
984 		 * development of the IPV6_RECVPATHMTU sockopt and
985 		 * associated work to implement RFC3542.
986 		 * It's not entirely clear what the intent of the API
987 		 * is at this point, so disable this code for now.
988 		 * The IPV6_RECVPATHMTU sockopt and/or IPV6_DONTFRAG
989 		 * will send notifications if the application requests.
990 		 */
991 
992 		/* Notify a proper path MTU to applications. */
993 		mtu32 = (u_int32_t)mtu;
994 		bzero(&ip6cp, sizeof(ip6cp));
995 		ip6cp.ip6c_cmdarg = (void *)&mtu32;
996 		pfctlinput2(PRC_MSGSIZE, (struct sockaddr *)&ro_pmtu->ro_dst,
997 		    (void *)&ip6cp);
998 #endif
999 
1000 		len = (mtu - hlen - sizeof(struct ip6_frag)) & ~7;
1001 		if (len < 8) {
1002 			error = EMSGSIZE;
1003 			in6_ifstat_inc(ifp, ifs6_out_fragfail);
1004 			goto bad;
1005 		}
1006 
1007 		mnext = &m->m_nextpkt;
1008 
1009 		/*
1010 		 * Change the next header field of the last header in the
1011 		 * unfragmentable part.
1012 		 */
1013 		if (exthdrs.ip6e_rthdr) {
1014 			nextproto = *mtod(exthdrs.ip6e_rthdr, u_char *);
1015 			*mtod(exthdrs.ip6e_rthdr, u_char *) = IPPROTO_FRAGMENT;
1016 		} else if (exthdrs.ip6e_dest1) {
1017 			nextproto = *mtod(exthdrs.ip6e_dest1, u_char *);
1018 			*mtod(exthdrs.ip6e_dest1, u_char *) = IPPROTO_FRAGMENT;
1019 		} else if (exthdrs.ip6e_hbh) {
1020 			nextproto = *mtod(exthdrs.ip6e_hbh, u_char *);
1021 			*mtod(exthdrs.ip6e_hbh, u_char *) = IPPROTO_FRAGMENT;
1022 		} else {
1023 			nextproto = ip6->ip6_nxt;
1024 			ip6->ip6_nxt = IPPROTO_FRAGMENT;
1025 		}
1026 
1027 		if ((m->m_pkthdr.csum_flags & (M_CSUM_UDPv6|M_CSUM_TCPv6))
1028 		    != 0) {
1029 			if (IN6_NEED_CHECKSUM(ifp,
1030 			    m->m_pkthdr.csum_flags &
1031 			    (M_CSUM_UDPv6|M_CSUM_TCPv6))) {
1032 				in6_delayed_cksum(m);
1033 			}
1034 			m->m_pkthdr.csum_flags &= ~(M_CSUM_UDPv6|M_CSUM_TCPv6);
1035 		}
1036 
1037 		/*
1038 		 * Loop through length of segment after first fragment,
1039 		 * make new header and copy data of each part and link onto
1040 		 * chain.
1041 		 */
1042 		m0 = m;
1043 		for (off = hlen; off < tlen; off += len) {
1044 			struct mbuf *mlast;
1045 
1046 			MGETHDR(m, M_DONTWAIT, MT_HEADER);
1047 			if (!m) {
1048 				error = ENOBUFS;
1049 				ip6stat.ip6s_odropped++;
1050 				goto sendorfree;
1051 			}
1052 			m->m_pkthdr.rcvif = NULL;
1053 			m->m_flags = m0->m_flags & M_COPYFLAGS;
1054 			*mnext = m;
1055 			mnext = &m->m_nextpkt;
1056 			m->m_data += max_linkhdr;
1057 			mhip6 = mtod(m, struct ip6_hdr *);
1058 			*mhip6 = *ip6;
1059 			m->m_len = sizeof(*mhip6);
1060 			error = ip6_insertfraghdr(m0, m, hlen, &ip6f);
1061 			if (error) {
1062 				ip6stat.ip6s_odropped++;
1063 				goto sendorfree;
1064 			}
1065 			ip6f->ip6f_offlg = htons((u_int16_t)((off - hlen) & ~7));
1066 			if (off + len >= tlen)
1067 				len = tlen - off;
1068 			else
1069 				ip6f->ip6f_offlg |= IP6F_MORE_FRAG;
1070 			mhip6->ip6_plen = htons((u_int16_t)(len + hlen +
1071 			    sizeof(*ip6f) - sizeof(struct ip6_hdr)));
1072 			if ((m_frgpart = m_copy(m0, off, len)) == 0) {
1073 				error = ENOBUFS;
1074 				ip6stat.ip6s_odropped++;
1075 				goto sendorfree;
1076 			}
1077 			for (mlast = m; mlast->m_next; mlast = mlast->m_next)
1078 				;
1079 			mlast->m_next = m_frgpart;
1080 			m->m_pkthdr.len = len + hlen + sizeof(*ip6f);
1081 			m->m_pkthdr.rcvif = (struct ifnet *)0;
1082 			ip6f->ip6f_reserved = 0;
1083 			ip6f->ip6f_ident = id;
1084 			ip6f->ip6f_nxt = nextproto;
1085 			ip6stat.ip6s_ofragments++;
1086 			in6_ifstat_inc(ifp, ifs6_out_fragcreat);
1087 		}
1088 
1089 		in6_ifstat_inc(ifp, ifs6_out_fragok);
1090 	}
1091 
1092 	/*
1093 	 * Remove leading garbages.
1094 	 */
1095 sendorfree:
1096 	m = m0->m_nextpkt;
1097 	m0->m_nextpkt = 0;
1098 	m_freem(m0);
1099 	for (m0 = m; m; m = m0) {
1100 		m0 = m->m_nextpkt;
1101 		m->m_nextpkt = 0;
1102 		if (error == 0) {
1103 			struct in6_ifaddr *ia6;
1104 			ip6 = mtod(m, struct ip6_hdr *);
1105 			ia6 = in6_ifawithifp(ifp, &ip6->ip6_src);
1106 			if (ia6) {
1107 				/*
1108 				 * Record statistics for this interface
1109 				 * address.
1110 				 */
1111 				ia6->ia_ifa.ifa_data.ifad_outbytes +=
1112 				    m->m_pkthdr.len;
1113 			}
1114 #ifdef IPSEC
1115 			/* clean ipsec history once it goes out of the node */
1116 			ipsec_delaux(m);
1117 #endif
1118 			error = nd6_output(ifp, origifp, m, dst, rt);
1119 		} else
1120 			m_freem(m);
1121 	}
1122 
1123 	if (error == 0)
1124 		ip6stat.ip6s_fragmented++;
1125 
1126 done:
1127 	if (ro == &ip6route && ro->ro_rt) { /* brace necessary for RTFREE */
1128 		RTFREE(ro->ro_rt);
1129 	} else if (ro_pmtu == &ip6route && ro_pmtu->ro_rt) {
1130 		RTFREE(ro_pmtu->ro_rt);
1131 	}
1132 
1133 #ifdef IPSEC
1134 	if (sp != NULL)
1135 		key_freesp(sp);
1136 #endif /* IPSEC */
1137 
1138 	return (error);
1139 
1140 freehdrs:
1141 	m_freem(exthdrs.ip6e_hbh);	/* m_freem will check if mbuf is 0 */
1142 	m_freem(exthdrs.ip6e_dest1);
1143 	m_freem(exthdrs.ip6e_rthdr);
1144 	m_freem(exthdrs.ip6e_dest2);
1145 	/* FALLTHROUGH */
1146 bad:
1147 	m_freem(m);
1148 	goto done;
1149 }
1150 
1151 static int
1152 ip6_copyexthdr(mp, hdr, hlen)
1153 	struct mbuf **mp;
1154 	caddr_t hdr;
1155 	int hlen;
1156 {
1157 	struct mbuf *m;
1158 
1159 	if (hlen > MCLBYTES)
1160 		return (ENOBUFS); /* XXX */
1161 
1162 	MGET(m, M_DONTWAIT, MT_DATA);
1163 	if (!m)
1164 		return (ENOBUFS);
1165 
1166 	if (hlen > MLEN) {
1167 		MCLGET(m, M_DONTWAIT);
1168 		if ((m->m_flags & M_EXT) == 0) {
1169 			m_free(m);
1170 			return (ENOBUFS);
1171 		}
1172 	}
1173 	m->m_len = hlen;
1174 	if (hdr)
1175 		bcopy(hdr, mtod(m, caddr_t), hlen);
1176 
1177 	*mp = m;
1178 	return (0);
1179 }
1180 
1181 /*
1182  * Process a delayed payload checksum calculation.
1183  */
1184 void
1185 in6_delayed_cksum(struct mbuf *m)
1186 {
1187 	uint16_t csum, offset;
1188 
1189 	KASSERT((m->m_pkthdr.csum_flags & (M_CSUM_UDPv6|M_CSUM_TCPv6)) != 0);
1190 	KASSERT((~m->m_pkthdr.csum_flags & (M_CSUM_UDPv6|M_CSUM_TCPv6)) != 0);
1191 	KASSERT((m->m_pkthdr.csum_flags
1192 	    & (M_CSUM_UDPv4|M_CSUM_TCPv4|M_CSUM_TSOv4)) == 0);
1193 
1194 	offset = M_CSUM_DATA_IPv6_HL(m->m_pkthdr.csum_data);
1195 	csum = in6_cksum(m, 0, offset, m->m_pkthdr.len - offset);
1196 	if (csum == 0 && (m->m_pkthdr.csum_flags & M_CSUM_UDPv6) != 0) {
1197 		csum = 0xffff;
1198 	}
1199 
1200 	offset += M_CSUM_DATA_IPv6_OFFSET(m->m_pkthdr.csum_data);
1201 	if ((offset + sizeof(csum)) > m->m_len) {
1202 		m_copyback(m, offset, sizeof(csum), &csum);
1203 	} else {
1204 		*(uint16_t *)(mtod(m, caddr_t) + offset) = csum;
1205 	}
1206 }
1207 
1208 /*
1209  * Insert jumbo payload option.
1210  */
1211 static int
1212 ip6_insert_jumboopt(exthdrs, plen)
1213 	struct ip6_exthdrs *exthdrs;
1214 	u_int32_t plen;
1215 {
1216 	struct mbuf *mopt;
1217 	u_int8_t *optbuf;
1218 	u_int32_t v;
1219 
1220 #define JUMBOOPTLEN	8	/* length of jumbo payload option and padding */
1221 
1222 	/*
1223 	 * If there is no hop-by-hop options header, allocate new one.
1224 	 * If there is one but it doesn't have enough space to store the
1225 	 * jumbo payload option, allocate a cluster to store the whole options.
1226 	 * Otherwise, use it to store the options.
1227 	 */
1228 	if (exthdrs->ip6e_hbh == 0) {
1229 		MGET(mopt, M_DONTWAIT, MT_DATA);
1230 		if (mopt == 0)
1231 			return (ENOBUFS);
1232 		mopt->m_len = JUMBOOPTLEN;
1233 		optbuf = mtod(mopt, u_int8_t *);
1234 		optbuf[1] = 0;	/* = ((JUMBOOPTLEN) >> 3) - 1 */
1235 		exthdrs->ip6e_hbh = mopt;
1236 	} else {
1237 		struct ip6_hbh *hbh;
1238 
1239 		mopt = exthdrs->ip6e_hbh;
1240 		if (M_TRAILINGSPACE(mopt) < JUMBOOPTLEN) {
1241 			/*
1242 			 * XXX assumption:
1243 			 * - exthdrs->ip6e_hbh is not referenced from places
1244 			 *   other than exthdrs.
1245 			 * - exthdrs->ip6e_hbh is not an mbuf chain.
1246 			 */
1247 			int oldoptlen = mopt->m_len;
1248 			struct mbuf *n;
1249 
1250 			/*
1251 			 * XXX: give up if the whole (new) hbh header does
1252 			 * not fit even in an mbuf cluster.
1253 			 */
1254 			if (oldoptlen + JUMBOOPTLEN > MCLBYTES)
1255 				return (ENOBUFS);
1256 
1257 			/*
1258 			 * As a consequence, we must always prepare a cluster
1259 			 * at this point.
1260 			 */
1261 			MGET(n, M_DONTWAIT, MT_DATA);
1262 			if (n) {
1263 				MCLGET(n, M_DONTWAIT);
1264 				if ((n->m_flags & M_EXT) == 0) {
1265 					m_freem(n);
1266 					n = NULL;
1267 				}
1268 			}
1269 			if (!n)
1270 				return (ENOBUFS);
1271 			n->m_len = oldoptlen + JUMBOOPTLEN;
1272 			bcopy(mtod(mopt, caddr_t), mtod(n, caddr_t),
1273 			    oldoptlen);
1274 			optbuf = mtod(n, u_int8_t *) + oldoptlen;
1275 			m_freem(mopt);
1276 			mopt = exthdrs->ip6e_hbh = n;
1277 		} else {
1278 			optbuf = mtod(mopt, u_int8_t *) + mopt->m_len;
1279 			mopt->m_len += JUMBOOPTLEN;
1280 		}
1281 		optbuf[0] = IP6OPT_PADN;
1282 		optbuf[1] = 0;
1283 
1284 		/*
1285 		 * Adjust the header length according to the pad and
1286 		 * the jumbo payload option.
1287 		 */
1288 		hbh = mtod(mopt, struct ip6_hbh *);
1289 		hbh->ip6h_len += (JUMBOOPTLEN >> 3);
1290 	}
1291 
1292 	/* fill in the option. */
1293 	optbuf[2] = IP6OPT_JUMBO;
1294 	optbuf[3] = 4;
1295 	v = (u_int32_t)htonl(plen + JUMBOOPTLEN);
1296 	bcopy(&v, &optbuf[4], sizeof(u_int32_t));
1297 
1298 	/* finally, adjust the packet header length */
1299 	exthdrs->ip6e_ip6->m_pkthdr.len += JUMBOOPTLEN;
1300 
1301 	return (0);
1302 #undef JUMBOOPTLEN
1303 }
1304 
1305 /*
1306  * Insert fragment header and copy unfragmentable header portions.
1307  */
1308 static int
1309 ip6_insertfraghdr(m0, m, hlen, frghdrp)
1310 	struct mbuf *m0, *m;
1311 	int hlen;
1312 	struct ip6_frag **frghdrp;
1313 {
1314 	struct mbuf *n, *mlast;
1315 
1316 	if (hlen > sizeof(struct ip6_hdr)) {
1317 		n = m_copym(m0, sizeof(struct ip6_hdr),
1318 		    hlen - sizeof(struct ip6_hdr), M_DONTWAIT);
1319 		if (n == 0)
1320 			return (ENOBUFS);
1321 		m->m_next = n;
1322 	} else
1323 		n = m;
1324 
1325 	/* Search for the last mbuf of unfragmentable part. */
1326 	for (mlast = n; mlast->m_next; mlast = mlast->m_next)
1327 		;
1328 
1329 	if ((mlast->m_flags & M_EXT) == 0 &&
1330 	    M_TRAILINGSPACE(mlast) >= sizeof(struct ip6_frag)) {
1331 		/* use the trailing space of the last mbuf for the fragment hdr */
1332 		*frghdrp = (struct ip6_frag *)(mtod(mlast, caddr_t) +
1333 		    mlast->m_len);
1334 		mlast->m_len += sizeof(struct ip6_frag);
1335 		m->m_pkthdr.len += sizeof(struct ip6_frag);
1336 	} else {
1337 		/* allocate a new mbuf for the fragment header */
1338 		struct mbuf *mfrg;
1339 
1340 		MGET(mfrg, M_DONTWAIT, MT_DATA);
1341 		if (mfrg == 0)
1342 			return (ENOBUFS);
1343 		mfrg->m_len = sizeof(struct ip6_frag);
1344 		*frghdrp = mtod(mfrg, struct ip6_frag *);
1345 		mlast->m_next = mfrg;
1346 	}
1347 
1348 	return (0);
1349 }
1350 
1351 static int
1352 ip6_getpmtu(ro_pmtu, ro, ifp, dst, mtup, alwaysfragp)
1353 	struct route_in6 *ro_pmtu, *ro;
1354 	struct ifnet *ifp;
1355 	struct in6_addr *dst;
1356 	u_long *mtup;
1357 	int *alwaysfragp;
1358 {
1359 	u_int32_t mtu = 0;
1360 	int alwaysfrag = 0;
1361 	int error = 0;
1362 
1363 	if (ro_pmtu != ro) {
1364 		/* The first hop and the final destination may differ. */
1365 		struct sockaddr_in6 *sa6_dst =
1366 		    (struct sockaddr_in6 *)&ro_pmtu->ro_dst;
1367 		if (ro_pmtu->ro_rt &&
1368 		    ((ro_pmtu->ro_rt->rt_flags & RTF_UP) == 0 ||
1369 		      !IN6_ARE_ADDR_EQUAL(&sa6_dst->sin6_addr, dst))) {
1370 			RTFREE(ro_pmtu->ro_rt);
1371 			ro_pmtu->ro_rt = (struct rtentry *)NULL;
1372 		}
1373 		if (ro_pmtu->ro_rt == NULL) {
1374 			bzero(sa6_dst, sizeof(*sa6_dst)); /* for safety */
1375 			sa6_dst->sin6_family = AF_INET6;
1376 			sa6_dst->sin6_len = sizeof(struct sockaddr_in6);
1377 			sa6_dst->sin6_addr = *dst;
1378 
1379 			rtalloc((struct route *)ro_pmtu);
1380 		}
1381 	}
1382 	if (ro_pmtu->ro_rt) {
1383 		u_int32_t ifmtu;
1384 
1385 		if (ifp == NULL)
1386 			ifp = ro_pmtu->ro_rt->rt_ifp;
1387 		ifmtu = IN6_LINKMTU(ifp);
1388 		mtu = ro_pmtu->ro_rt->rt_rmx.rmx_mtu;
1389 		if (mtu == 0)
1390 			mtu = ifmtu;
1391 		else if (mtu < IPV6_MMTU) {
1392 			/*
1393 			 * RFC2460 section 5, last paragraph:
1394 			 * if we record ICMPv6 too big message with
1395 			 * mtu < IPV6_MMTU, transmit packets sized IPV6_MMTU
1396 			 * or smaller, with fragment header attached.
1397 			 * (fragment header is needed regardless from the
1398 			 * packet size, for translators to identify packets)
1399 			 */
1400 			alwaysfrag = 1;
1401 			mtu = IPV6_MMTU;
1402 		} else if (mtu > ifmtu) {
1403 			/*
1404 			 * The MTU on the route is larger than the MTU on
1405 			 * the interface!  This shouldn't happen, unless the
1406 			 * MTU of the interface has been changed after the
1407 			 * interface was brought up.  Change the MTU in the
1408 			 * route to match the interface MTU (as long as the
1409 			 * field isn't locked).
1410 			 */
1411 			mtu = ifmtu;
1412 			if (!(ro_pmtu->ro_rt->rt_rmx.rmx_locks & RTV_MTU))
1413 				ro_pmtu->ro_rt->rt_rmx.rmx_mtu = mtu;
1414 		}
1415 	} else if (ifp) {
1416 		mtu = IN6_LINKMTU(ifp);
1417 	} else
1418 		error = EHOSTUNREACH; /* XXX */
1419 
1420 	*mtup = mtu;
1421 	if (alwaysfragp)
1422 		*alwaysfragp = alwaysfrag;
1423 	return (error);
1424 }
1425 
1426 /*
1427  * IP6 socket option processing.
1428  */
1429 int
1430 ip6_ctloutput(op, so, level, optname, mp)
1431 	int op;
1432 	struct socket *so;
1433 	int level, optname;
1434 	struct mbuf **mp;
1435 {
1436 	int privileged, optdatalen, uproto;
1437 	void *optdata;
1438 	struct in6pcb *in6p = sotoin6pcb(so);
1439 	struct mbuf *m = *mp;
1440 	int error, optval;
1441 	int optlen;
1442 	struct lwp *l = curlwp;	/* XXX */
1443 
1444 	optlen = m ? m->m_len : 0;
1445 	error = optval = 0;
1446 	privileged = (l == 0 || kauth_authorize_generic(l->l_cred,
1447 	    KAUTH_GENERIC_ISSUSER, &l->l_acflag)) ? 0 : 1;
1448 	uproto = (int)so->so_proto->pr_protocol;
1449 
1450 	if (level == IPPROTO_IPV6) {
1451 		switch (op) {
1452 		case PRCO_SETOPT:
1453 			switch (optname) {
1454 #ifdef RFC2292
1455 			case IPV6_2292PKTOPTIONS:
1456 				/* m is freed in ip6_pcbopts */
1457 				error = ip6_pcbopts(&in6p->in6p_outputopts,
1458 				    m, so);
1459 				break;
1460 #endif
1461 
1462 			/*
1463 			 * Use of some Hop-by-Hop options or some
1464 			 * Destination options, might require special
1465 			 * privilege.  That is, normal applications
1466 			 * (without special privilege) might be forbidden
1467 			 * from setting certain options in outgoing packets,
1468 			 * and might never see certain options in received
1469 			 * packets. [RFC 2292 Section 6]
1470 			 * KAME specific note:
1471 			 *  KAME prevents non-privileged users from sending or
1472 			 *  receiving ANY hbh/dst options in order to avoid
1473 			 *  overhead of parsing options in the kernel.
1474 			 */
1475 			case IPV6_RECVHOPOPTS:
1476 			case IPV6_RECVDSTOPTS:
1477 			case IPV6_RECVRTHDRDSTOPTS:
1478 				if (!privileged) {
1479 					error = EPERM;
1480 					break;
1481 				}
1482 				/* FALLTHROUGH */
1483 			case IPV6_UNICAST_HOPS:
1484 			case IPV6_HOPLIMIT:
1485 			case IPV6_FAITH:
1486 
1487 			case IPV6_RECVPKTINFO:
1488 			case IPV6_RECVHOPLIMIT:
1489 			case IPV6_RECVRTHDR:
1490 			case IPV6_RECVPATHMTU:
1491 			case IPV6_RECVTCLASS:
1492 			case IPV6_V6ONLY:
1493 				if (optlen != sizeof(int)) {
1494 					error = EINVAL;
1495 					break;
1496 				}
1497 				optval = *mtod(m, int *);
1498 				switch (optname) {
1499 
1500 				case IPV6_UNICAST_HOPS:
1501 					if (optval < -1 || optval >= 256)
1502 						error = EINVAL;
1503 					else {
1504 						/* -1 = kernel default */
1505 						in6p->in6p_hops = optval;
1506 					}
1507 					break;
1508 #define OPTSET(bit) \
1509 do { \
1510 	if (optval) \
1511 		in6p->in6p_flags |= (bit); \
1512 	else \
1513 		in6p->in6p_flags &= ~(bit); \
1514 } while (/*CONSTCOND*/ 0)
1515 
1516 #ifdef RFC2292
1517 #define OPTSET2292(bit) 			\
1518 do { 						\
1519 	in6p->in6p_flags |= IN6P_RFC2292; 	\
1520 	if (optval) 				\
1521 		in6p->in6p_flags |= (bit); 	\
1522 	else 					\
1523 		in6p->in6p_flags &= ~(bit); 	\
1524 } while (/*CONSTCOND*/ 0)
1525 #endif
1526 
1527 #define OPTBIT(bit) (in6p->in6p_flags & (bit) ? 1 : 0)
1528 
1529 				case IPV6_RECVPKTINFO:
1530 #ifdef RFC2292
1531 					/* cannot mix with RFC2292 */
1532 					if (OPTBIT(IN6P_RFC2292)) {
1533 						error = EINVAL;
1534 						break;
1535 					}
1536 #endif
1537 					OPTSET(IN6P_PKTINFO);
1538 					break;
1539 
1540 				case IPV6_HOPLIMIT:
1541 				{
1542 					struct ip6_pktopts **optp;
1543 
1544 #ifdef RFC2292
1545 					/* cannot mix with RFC2292 */
1546 					if (OPTBIT(IN6P_RFC2292)) {
1547 						error = EINVAL;
1548 						break;
1549 					}
1550 #endif
1551 					optp = &in6p->in6p_outputopts;
1552 					error = ip6_pcbopt(IPV6_HOPLIMIT,
1553 							   (u_char *)&optval,
1554 							   sizeof(optval),
1555 							   optp,
1556 							   privileged, uproto);
1557 					break;
1558 				}
1559 
1560 				case IPV6_RECVHOPLIMIT:
1561 #ifdef RFC2292
1562 					/* cannot mix with RFC2292 */
1563 					if (OPTBIT(IN6P_RFC2292)) {
1564 						error = EINVAL;
1565 						break;
1566 					}
1567 #endif
1568 					OPTSET(IN6P_HOPLIMIT);
1569 					break;
1570 
1571 				case IPV6_RECVHOPOPTS:
1572 #ifdef RFC2292
1573 					/* cannot mix with RFC2292 */
1574 					if (OPTBIT(IN6P_RFC2292)) {
1575 						error = EINVAL;
1576 						break;
1577 					}
1578 #endif
1579 					OPTSET(IN6P_HOPOPTS);
1580 					break;
1581 
1582 				case IPV6_RECVDSTOPTS:
1583 #ifdef RFC2292
1584 					/* cannot mix with RFC2292 */
1585 					if (OPTBIT(IN6P_RFC2292)) {
1586 						error = EINVAL;
1587 						break;
1588 					}
1589 #endif
1590 					OPTSET(IN6P_DSTOPTS);
1591 					break;
1592 
1593 				case IPV6_RECVRTHDRDSTOPTS:
1594 #ifdef RFC2292
1595 					/* cannot mix with RFC2292 */
1596 					if (OPTBIT(IN6P_RFC2292)) {
1597 						error = EINVAL;
1598 						break;
1599 					}
1600 #endif
1601 					OPTSET(IN6P_RTHDRDSTOPTS);
1602 					break;
1603 
1604 				case IPV6_RECVRTHDR:
1605 #ifdef RFC2292
1606 					/* cannot mix with RFC2292 */
1607 					if (OPTBIT(IN6P_RFC2292)) {
1608 						error = EINVAL;
1609 						break;
1610 					}
1611 #endif
1612 					OPTSET(IN6P_RTHDR);
1613 					break;
1614 
1615 				case IPV6_FAITH:
1616 					OPTSET(IN6P_FAITH);
1617 					break;
1618 
1619 				case IPV6_RECVPATHMTU:
1620 					/*
1621 					 * We ignore this option for TCP
1622 					 * sockets.
1623 					 * (RFC3542 leaves this case
1624 					 * unspecified.)
1625 					 */
1626 					if (uproto != IPPROTO_TCP)
1627 						OPTSET(IN6P_MTU);
1628 					break;
1629 
1630 				case IPV6_V6ONLY:
1631 					/*
1632 					 * make setsockopt(IPV6_V6ONLY)
1633 					 * available only prior to bind(2).
1634 					 * see ipng mailing list, Jun 22 2001.
1635 					 */
1636 					if (in6p->in6p_lport ||
1637 					    !IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_laddr)) {
1638 						error = EINVAL;
1639 						break;
1640 					}
1641 #ifdef INET6_BINDV6ONLY
1642 					if (!optval)
1643 						error = EINVAL;
1644 #else
1645 					OPTSET(IN6P_IPV6_V6ONLY);
1646 #endif
1647 					break;
1648 				case IPV6_RECVTCLASS:
1649 #ifdef RFC2292
1650 					/* cannot mix with RFC2292 XXX */
1651 					if (OPTBIT(IN6P_RFC2292)) {
1652 						error = EINVAL;
1653 						break;
1654 					}
1655 #endif
1656 					OPTSET(IN6P_TCLASS);
1657 					break;
1658 
1659 				}
1660 				break;
1661 
1662 			case IPV6_OTCLASS:
1663 			{
1664 				struct ip6_pktopts **optp;
1665 				u_int8_t tclass;
1666 
1667 				if (optlen != sizeof(tclass)) {
1668 					error = EINVAL;
1669 					break;
1670 				}
1671 				tclass = *mtod(m, u_int8_t *);
1672 				optp = &in6p->in6p_outputopts;
1673 				error = ip6_pcbopt(optname,
1674 						   (u_char *)&tclass,
1675 						   sizeof(tclass),
1676 						   optp,
1677 						   privileged, uproto);
1678 				break;
1679 			}
1680 
1681 			case IPV6_TCLASS:
1682 			case IPV6_DONTFRAG:
1683 			case IPV6_USE_MIN_MTU:
1684 				if (optlen != sizeof(optval)) {
1685 					error = EINVAL;
1686 					break;
1687 				}
1688 				optval = *mtod(m, int *);
1689 				{
1690 					struct ip6_pktopts **optp;
1691 					optp = &in6p->in6p_outputopts;
1692 					error = ip6_pcbopt(optname,
1693 							   (u_char *)&optval,
1694 							   sizeof(optval),
1695 							   optp,
1696 							   privileged, uproto);
1697 					break;
1698 				}
1699 
1700 #ifdef RFC2292
1701 			case IPV6_2292PKTINFO:
1702 			case IPV6_2292HOPLIMIT:
1703 			case IPV6_2292HOPOPTS:
1704 			case IPV6_2292DSTOPTS:
1705 			case IPV6_2292RTHDR:
1706 				/* RFC 2292 */
1707 				if (optlen != sizeof(int)) {
1708 					error = EINVAL;
1709 					break;
1710 				}
1711 				optval = *mtod(m, int *);
1712 				switch (optname) {
1713 				case IPV6_2292PKTINFO:
1714 					OPTSET2292(IN6P_PKTINFO);
1715 					break;
1716 				case IPV6_2292HOPLIMIT:
1717 					OPTSET2292(IN6P_HOPLIMIT);
1718 					break;
1719 				case IPV6_2292HOPOPTS:
1720 					/*
1721 					 * Check super-user privilege.
1722 					 * See comments for IPV6_RECVHOPOPTS.
1723 					 */
1724 					if (!privileged)
1725 						return (EPERM);
1726 					OPTSET2292(IN6P_HOPOPTS);
1727 					break;
1728 				case IPV6_2292DSTOPTS:
1729 					if (!privileged)
1730 						return (EPERM);
1731 					OPTSET2292(IN6P_DSTOPTS|IN6P_RTHDRDSTOPTS); /* XXX */
1732 					break;
1733 				case IPV6_2292RTHDR:
1734 					OPTSET2292(IN6P_RTHDR);
1735 					break;
1736 				}
1737 				break;
1738 #endif
1739 			case IPV6_PKTINFO:
1740 			case IPV6_HOPOPTS:
1741 			case IPV6_RTHDR:
1742 			case IPV6_DSTOPTS:
1743 			case IPV6_RTHDRDSTOPTS:
1744 			case IPV6_NEXTHOP:
1745 			{
1746 				/* new advanced API (RFC3542) */
1747 				u_char *optbuf;
1748 				int optbuflen;
1749 				struct ip6_pktopts **optp;
1750 
1751 #ifdef RFC2292
1752 				/* cannot mix with RFC2292 */
1753 				if (OPTBIT(IN6P_RFC2292)) {
1754 					error = EINVAL;
1755 					break;
1756 				}
1757 #endif
1758 
1759 				if (m && m->m_next) {
1760 					error = EINVAL;	/* XXX */
1761 					break;
1762 				}
1763 				if (m) {
1764 					optbuf = mtod(m, u_char *);
1765 					optbuflen = m->m_len;
1766 				} else {
1767 					optbuf = NULL;
1768 					optbuflen = 0;
1769 				}
1770 				optp = &in6p->in6p_outputopts;
1771 				error = ip6_pcbopt(optname,
1772 						   optbuf, optbuflen,
1773 						   optp, privileged, uproto);
1774 				break;
1775 			}
1776 #undef OPTSET
1777 
1778 			case IPV6_MULTICAST_IF:
1779 			case IPV6_MULTICAST_HOPS:
1780 			case IPV6_MULTICAST_LOOP:
1781 			case IPV6_JOIN_GROUP:
1782 			case IPV6_LEAVE_GROUP:
1783                                 error = ip6_setmoptions(optname,
1784 				    &in6p->in6p_moptions, m);
1785 				break;
1786 
1787 			case IPV6_PORTRANGE:
1788 				optval = *mtod(m, int *);
1789 
1790 				switch (optval) {
1791 				case IPV6_PORTRANGE_DEFAULT:
1792 					in6p->in6p_flags &= ~(IN6P_LOWPORT);
1793 					in6p->in6p_flags &= ~(IN6P_HIGHPORT);
1794 					break;
1795 
1796 				case IPV6_PORTRANGE_HIGH:
1797 					in6p->in6p_flags &= ~(IN6P_LOWPORT);
1798 					in6p->in6p_flags |= IN6P_HIGHPORT;
1799 					break;
1800 
1801 				case IPV6_PORTRANGE_LOW:
1802 					in6p->in6p_flags &= ~(IN6P_HIGHPORT);
1803 					in6p->in6p_flags |= IN6P_LOWPORT;
1804 					break;
1805 
1806 				default:
1807 					error = EINVAL;
1808 					break;
1809 				}
1810 				break;
1811 
1812 #ifdef IPSEC
1813 			case IPV6_IPSEC_POLICY:
1814 			{
1815 				caddr_t req = NULL;
1816 				size_t len = 0;
1817 				if (m) {
1818 					req = mtod(m, caddr_t);
1819 					len = m->m_len;
1820 				}
1821 				error = ipsec6_set_policy(in6p, optname, req,
1822 							  len, privileged);
1823 			}
1824 				break;
1825 #endif /* IPSEC */
1826 
1827 			default:
1828 				error = ENOPROTOOPT;
1829 				break;
1830 			}
1831 			if (m)
1832 				(void)m_free(m);
1833 			break;
1834 
1835 		case PRCO_GETOPT:
1836 			switch (optname) {
1837 #ifdef RFC2292
1838 			case IPV6_2292PKTOPTIONS:
1839 				/*
1840 				 * RFC3542 (effectively) deprecated the
1841 				 * semantics of the 2292-style pktoptions.
1842 				 * Since it was not reliable in nature (i.e.,
1843 				 * applications had to expect the lack of some
1844 				 * information after all), it would make sense
1845 				 * to simplify this part by always returning
1846 				 * empty data.
1847 				 */
1848 				*mp = m_get(M_WAIT, MT_SOOPTS);
1849 				(*mp)->m_len = 0;
1850 				break;
1851 #endif
1852 
1853 			case IPV6_RECVHOPOPTS:
1854 			case IPV6_RECVDSTOPTS:
1855 			case IPV6_RECVRTHDRDSTOPTS:
1856 			case IPV6_UNICAST_HOPS:
1857 			case IPV6_RECVPKTINFO:
1858 			case IPV6_RECVHOPLIMIT:
1859 			case IPV6_RECVRTHDR:
1860 			case IPV6_RECVPATHMTU:
1861 
1862 			case IPV6_FAITH:
1863 			case IPV6_V6ONLY:
1864 			case IPV6_PORTRANGE:
1865 			case IPV6_RECVTCLASS:
1866 				switch (optname) {
1867 
1868 				case IPV6_RECVHOPOPTS:
1869 					optval = OPTBIT(IN6P_HOPOPTS);
1870 					break;
1871 
1872 				case IPV6_RECVDSTOPTS:
1873 					optval = OPTBIT(IN6P_DSTOPTS);
1874 					break;
1875 
1876 				case IPV6_RECVRTHDRDSTOPTS:
1877 					optval = OPTBIT(IN6P_RTHDRDSTOPTS);
1878 					break;
1879 
1880 				case IPV6_UNICAST_HOPS:
1881 					optval = in6p->in6p_hops;
1882 					break;
1883 
1884 				case IPV6_RECVPKTINFO:
1885 					optval = OPTBIT(IN6P_PKTINFO);
1886 					break;
1887 
1888 				case IPV6_RECVHOPLIMIT:
1889 					optval = OPTBIT(IN6P_HOPLIMIT);
1890 					break;
1891 
1892 				case IPV6_RECVRTHDR:
1893 					optval = OPTBIT(IN6P_RTHDR);
1894 					break;
1895 
1896 				case IPV6_RECVPATHMTU:
1897 					optval = OPTBIT(IN6P_MTU);
1898 					break;
1899 
1900 				case IPV6_FAITH:
1901 					optval = OPTBIT(IN6P_FAITH);
1902 					break;
1903 
1904 				case IPV6_V6ONLY:
1905 					optval = OPTBIT(IN6P_IPV6_V6ONLY);
1906 					break;
1907 
1908 				case IPV6_PORTRANGE:
1909 				    {
1910 					int flags;
1911 					flags = in6p->in6p_flags;
1912 					if (flags & IN6P_HIGHPORT)
1913 						optval = IPV6_PORTRANGE_HIGH;
1914 					else if (flags & IN6P_LOWPORT)
1915 						optval = IPV6_PORTRANGE_LOW;
1916 					else
1917 						optval = 0;
1918 					break;
1919 				    }
1920 				case IPV6_RECVTCLASS:
1921 					optval = OPTBIT(IN6P_TCLASS);
1922 					break;
1923 
1924 				}
1925 				if (error)
1926 					break;
1927 				*mp = m = m_get(M_WAIT, MT_SOOPTS);
1928 				m->m_len = sizeof(int);
1929 				*mtod(m, int *) = optval;
1930 				break;
1931 
1932 			case IPV6_PATHMTU:
1933 			    {
1934 				u_long pmtu = 0;
1935 				struct ip6_mtuinfo mtuinfo;
1936 				struct route_in6 *ro = (struct route_in6 *)&in6p
1937 ->in6p_route;
1938 
1939 				if (!(so->so_state & SS_ISCONNECTED))
1940 					return (ENOTCONN);
1941 				/*
1942 				 * XXX: we dot not consider the case of source
1943 				 * routing, or optional information to specify
1944 				 * the outgoing interface.
1945 				 */
1946 				error = ip6_getpmtu(ro, NULL, NULL,
1947 				    &in6p->in6p_faddr, &pmtu, NULL);
1948 				if (error)
1949 					break;
1950 				if (pmtu > IPV6_MAXPACKET)
1951 					pmtu = IPV6_MAXPACKET;
1952 
1953 				memset(&mtuinfo, 0, sizeof(mtuinfo));
1954 				mtuinfo.ip6m_mtu = (u_int32_t)pmtu;
1955 				optdata = (void *)&mtuinfo;
1956 				optdatalen = sizeof(mtuinfo);
1957 				if (optdatalen > MCLBYTES)
1958 					return (EMSGSIZE); /* XXX */
1959 				*mp = m = m_get(M_WAIT, MT_SOOPTS);
1960 				if (optdatalen > MLEN)
1961 					MCLGET(m, M_WAIT);
1962 				m->m_len = optdatalen;
1963 				memcpy(mtod(m, void *), optdata, optdatalen);
1964 				break;
1965 			    }
1966 
1967 #ifdef RFC2292
1968 			case IPV6_2292PKTINFO:
1969 			case IPV6_2292HOPLIMIT:
1970 			case IPV6_2292HOPOPTS:
1971 			case IPV6_2292RTHDR:
1972 			case IPV6_2292DSTOPTS:
1973 				switch (optname) {
1974 				case IPV6_2292PKTINFO:
1975 					optval = OPTBIT(IN6P_PKTINFO);
1976 					break;
1977 				case IPV6_2292HOPLIMIT:
1978 					optval = OPTBIT(IN6P_HOPLIMIT);
1979 					break;
1980 				case IPV6_2292HOPOPTS:
1981 					optval = OPTBIT(IN6P_HOPOPTS);
1982 					break;
1983 				case IPV6_2292RTHDR:
1984 					optval = OPTBIT(IN6P_RTHDR);
1985 					break;
1986 				case IPV6_2292DSTOPTS:
1987 					optval = OPTBIT(IN6P_DSTOPTS|IN6P_RTHDRDSTOPTS);
1988 					break;
1989 				}
1990 				*mp = m = m_get(M_WAIT, MT_SOOPTS);
1991 				m->m_len = sizeof(int);
1992 				*mtod(m, int *) = optval;
1993 				break;
1994 #endif
1995 			case IPV6_PKTINFO:
1996 			case IPV6_HOPOPTS:
1997 			case IPV6_RTHDR:
1998 			case IPV6_DSTOPTS:
1999 			case IPV6_RTHDRDSTOPTS:
2000 			case IPV6_NEXTHOP:
2001 			case IPV6_OTCLASS:
2002 			case IPV6_TCLASS:
2003 			case IPV6_DONTFRAG:
2004 			case IPV6_USE_MIN_MTU:
2005 				error = ip6_getpcbopt(in6p->in6p_outputopts,
2006 				    optname, mp);
2007 				break;
2008 
2009 			case IPV6_MULTICAST_IF:
2010 			case IPV6_MULTICAST_HOPS:
2011 			case IPV6_MULTICAST_LOOP:
2012 			case IPV6_JOIN_GROUP:
2013 			case IPV6_LEAVE_GROUP:
2014 				error = ip6_getmoptions(optname,
2015 				    in6p->in6p_moptions, mp);
2016 				break;
2017 
2018 #ifdef IPSEC
2019 			case IPV6_IPSEC_POLICY:
2020 			    {
2021 				caddr_t req = NULL;
2022 				size_t len = 0;
2023 				if (m) {
2024 					req = mtod(m, caddr_t);
2025 					len = m->m_len;
2026 				}
2027 				error = ipsec6_get_policy(in6p, req, len, mp);
2028 				break;
2029 			    }
2030 #endif /* IPSEC */
2031 
2032 
2033 
2034 
2035 			default:
2036 				error = ENOPROTOOPT;
2037 				break;
2038 			}
2039 			break;
2040 		}
2041 	} else {
2042 		error = EINVAL;
2043 		if (op == PRCO_SETOPT && *mp)
2044 			(void)m_free(*mp);
2045 	}
2046 	return (error);
2047 }
2048 
2049 int
2050 ip6_raw_ctloutput(op, so, level, optname, mp)
2051 	int op;
2052 	struct socket *so;
2053 	int level, optname;
2054 	struct mbuf **mp;
2055 {
2056 	int error = 0, optval, optlen;
2057 	const int icmp6off = offsetof(struct icmp6_hdr, icmp6_cksum);
2058 	struct in6pcb *in6p = sotoin6pcb(so);
2059 	struct mbuf *m = *mp;
2060 
2061 	optlen = m ? m->m_len : 0;
2062 
2063 	if (level != IPPROTO_IPV6) {
2064 		if (op == PRCO_SETOPT && *mp)
2065 			(void)m_free(*mp);
2066 		return (EINVAL);
2067 	}
2068 
2069 	switch (optname) {
2070 	case IPV6_CHECKSUM:
2071 		/*
2072 		 * For ICMPv6 sockets, no modification allowed for checksum
2073 		 * offset, permit "no change" values to help existing apps.
2074 		 *
2075 		 * XXX RFC3542 says: "An attempt to set IPV6_CHECKSUM
2076 		 * for an ICMPv6 socket will fail."  The current
2077 		 * behavior does not meet RFC3542.
2078 		 */
2079 		switch (op) {
2080 		case PRCO_SETOPT:
2081 			if (optlen != sizeof(int)) {
2082 				error = EINVAL;
2083 				break;
2084 			}
2085 			optval = *mtod(m, int *);
2086 			if ((optval % 2) != 0) {
2087 				/* the API assumes even offset values */
2088 				error = EINVAL;
2089 			} else if (so->so_proto->pr_protocol ==
2090 			    IPPROTO_ICMPV6) {
2091 				if (optval != icmp6off)
2092 					error = EINVAL;
2093 			} else
2094 				in6p->in6p_cksum = optval;
2095 			break;
2096 
2097 		case PRCO_GETOPT:
2098 			if (so->so_proto->pr_protocol == IPPROTO_ICMPV6)
2099 				optval = icmp6off;
2100 			else
2101 				optval = in6p->in6p_cksum;
2102 
2103 			*mp = m = m_get(M_WAIT, MT_SOOPTS);
2104 			m->m_len = sizeof(int);
2105 			*mtod(m, int *) = optval;
2106 			break;
2107 
2108 		default:
2109 			error = EINVAL;
2110 			break;
2111 		}
2112 		break;
2113 
2114 	default:
2115 		error = ENOPROTOOPT;
2116 		break;
2117 	}
2118 
2119 	if (op == PRCO_SETOPT && m)
2120 		(void)m_free(m);
2121 
2122 	return (error);
2123 }
2124 
2125 #ifdef RFC2292
2126 /*
2127  * Set up IP6 options in pcb for insertion in output packets or
2128  * specifying behavior of outgoing packets.
2129  */
2130 static int
2131 ip6_pcbopts(pktopt, m, so)
2132 	struct ip6_pktopts **pktopt;
2133 	struct mbuf *m;
2134 	struct socket *so;
2135 {
2136 	struct ip6_pktopts *opt = *pktopt;
2137 	int error = 0;
2138 	struct lwp *l = curlwp;	/* XXX */
2139 	int priv = 0;
2140 
2141 	/* turn off any old options. */
2142 	if (opt) {
2143 #ifdef DIAGNOSTIC
2144 	    if (opt->ip6po_pktinfo || opt->ip6po_nexthop ||
2145 		opt->ip6po_hbh || opt->ip6po_dest1 || opt->ip6po_dest2 ||
2146 		opt->ip6po_rhinfo.ip6po_rhi_rthdr)
2147 		    printf("ip6_pcbopts: all specified options are cleared.\n");
2148 #endif
2149 		ip6_clearpktopts(opt, -1);
2150 	} else
2151 		opt = malloc(sizeof(*opt), M_IP6OPT, M_WAITOK);
2152 	*pktopt = NULL;
2153 
2154 	if (!m || m->m_len == 0) {
2155 		/*
2156 		 * Only turning off any previous options, regardless of
2157 		 * whether the opt is just created or given.
2158 		 */
2159 		free(opt, M_IP6OPT);
2160 		return (0);
2161 	}
2162 
2163 	/*  set options specified by user. */
2164 	if (l && !kauth_authorize_generic(l->l_cred, KAUTH_GENERIC_ISSUSER,
2165 	    &l->l_acflag))
2166 		priv = 1;
2167 	if ((error = ip6_setpktopts(m, opt, NULL, priv,
2168 	    so->so_proto->pr_protocol)) != 0) {
2169 		ip6_clearpktopts(opt, -1); /* XXX: discard all options */
2170 		free(opt, M_IP6OPT);
2171 		return (error);
2172 	}
2173 	*pktopt = opt;
2174 	return (0);
2175 }
2176 #endif
2177 
2178 /*
2179  * initialize ip6_pktopts.  beware that there are non-zero default values in
2180  * the struct.
2181  */
2182 void
2183 ip6_initpktopts(struct ip6_pktopts *opt)
2184 {
2185 
2186 	memset(opt, 0, sizeof(*opt));
2187 	opt->ip6po_hlim = -1;	/* -1 means default hop limit */
2188 	opt->ip6po_tclass = -1;	/* -1 means default traffic class */
2189 	opt->ip6po_minmtu = IP6PO_MINMTU_MCASTONLY;
2190 }
2191 
2192 #define sin6tosa(sin6)	((struct sockaddr *)(sin6)) /* XXX */
2193 static int
2194 ip6_pcbopt(int optname, u_char *buf, int len, struct ip6_pktopts **pktopt,
2195     int priv, int uproto)
2196 {
2197 	struct ip6_pktopts *opt;
2198 
2199 	if (*pktopt == NULL) {
2200 		*pktopt = malloc(sizeof(struct ip6_pktopts), M_IP6OPT,
2201 		    M_WAITOK);
2202 		ip6_initpktopts(*pktopt);
2203 	}
2204 	opt = *pktopt;
2205 
2206 	return (ip6_setpktopt(optname, buf, len, opt, priv, 1, 0, uproto));
2207 }
2208 
2209 static int
2210 ip6_getpcbopt(struct ip6_pktopts *pktopt, int optname, struct mbuf **mp)
2211 {
2212 	void *optdata = NULL;
2213 	int optdatalen = 0;
2214 	struct ip6_ext *ip6e;
2215 	int error = 0;
2216 	struct in6_pktinfo null_pktinfo;
2217 	int deftclass = 0, on;
2218 	int defminmtu = IP6PO_MINMTU_MCASTONLY;
2219 	struct mbuf *m;
2220 
2221 	switch (optname) {
2222 	case IPV6_PKTINFO:
2223 		if (pktopt && pktopt->ip6po_pktinfo)
2224 			optdata = (void *)pktopt->ip6po_pktinfo;
2225 		else {
2226 			/* XXX: we don't have to do this every time... */
2227 			memset(&null_pktinfo, 0, sizeof(null_pktinfo));
2228 			optdata = (void *)&null_pktinfo;
2229 		}
2230 		optdatalen = sizeof(struct in6_pktinfo);
2231 		break;
2232 	case IPV6_OTCLASS:
2233 		/* XXX */
2234 		return (EINVAL);
2235 	case IPV6_TCLASS:
2236 		if (pktopt && pktopt->ip6po_tclass >= 0)
2237 			optdata = (void *)&pktopt->ip6po_tclass;
2238 		else
2239 			optdata = (void *)&deftclass;
2240 		optdatalen = sizeof(int);
2241 		break;
2242 	case IPV6_HOPOPTS:
2243 		if (pktopt && pktopt->ip6po_hbh) {
2244 			optdata = (void *)pktopt->ip6po_hbh;
2245 			ip6e = (struct ip6_ext *)pktopt->ip6po_hbh;
2246 			optdatalen = (ip6e->ip6e_len + 1) << 3;
2247 		}
2248 		break;
2249 	case IPV6_RTHDR:
2250 		if (pktopt && pktopt->ip6po_rthdr) {
2251 			optdata = (void *)pktopt->ip6po_rthdr;
2252 			ip6e = (struct ip6_ext *)pktopt->ip6po_rthdr;
2253 			optdatalen = (ip6e->ip6e_len + 1) << 3;
2254 		}
2255 		break;
2256 	case IPV6_RTHDRDSTOPTS:
2257 		if (pktopt && pktopt->ip6po_dest1) {
2258 			optdata = (void *)pktopt->ip6po_dest1;
2259 			ip6e = (struct ip6_ext *)pktopt->ip6po_dest1;
2260 			optdatalen = (ip6e->ip6e_len + 1) << 3;
2261 		}
2262 		break;
2263 	case IPV6_DSTOPTS:
2264 		if (pktopt && pktopt->ip6po_dest2) {
2265 			optdata = (void *)pktopt->ip6po_dest2;
2266 			ip6e = (struct ip6_ext *)pktopt->ip6po_dest2;
2267 			optdatalen = (ip6e->ip6e_len + 1) << 3;
2268 		}
2269 		break;
2270 	case IPV6_NEXTHOP:
2271 		if (pktopt && pktopt->ip6po_nexthop) {
2272 			optdata = (void *)pktopt->ip6po_nexthop;
2273 			optdatalen = pktopt->ip6po_nexthop->sa_len;
2274 		}
2275 		break;
2276 	case IPV6_USE_MIN_MTU:
2277 		if (pktopt)
2278 			optdata = (void *)&pktopt->ip6po_minmtu;
2279 		else
2280 			optdata = (void *)&defminmtu;
2281 		optdatalen = sizeof(int);
2282 		break;
2283 	case IPV6_DONTFRAG:
2284 		if (pktopt && ((pktopt->ip6po_flags) & IP6PO_DONTFRAG))
2285 			on = 1;
2286 		else
2287 			on = 0;
2288 		optdata = (void *)&on;
2289 		optdatalen = sizeof(on);
2290 		break;
2291 	default:		/* should not happen */
2292 #ifdef DIAGNOSTIC
2293 		panic("ip6_getpcbopt: unexpected option\n");
2294 #endif
2295 		return (ENOPROTOOPT);
2296 	}
2297 
2298 	if (optdatalen > MCLBYTES)
2299 		return (EMSGSIZE); /* XXX */
2300 	*mp = m = m_get(M_WAIT, MT_SOOPTS);
2301 	if (optdatalen > MLEN)
2302 		MCLGET(m, M_WAIT);
2303 	m->m_len = optdatalen;
2304 	if (optdatalen)
2305 		memcpy(mtod(m, void *), optdata, optdatalen);
2306 
2307 	return (error);
2308 }
2309 
2310 void
2311 ip6_clearpktopts(struct ip6_pktopts *pktopt, int optname)
2312 {
2313 	if (optname == -1 || optname == IPV6_PKTINFO) {
2314 		if (pktopt->ip6po_pktinfo)
2315 			free(pktopt->ip6po_pktinfo, M_IP6OPT);
2316 		pktopt->ip6po_pktinfo = NULL;
2317 	}
2318 	if (optname == -1 || optname == IPV6_HOPLIMIT)
2319 		pktopt->ip6po_hlim = -1;
2320 	if (optname == -1 || optname == IPV6_TCLASS)
2321 		pktopt->ip6po_tclass = -1;
2322 	if (optname == -1 || optname == IPV6_NEXTHOP) {
2323 		if (pktopt->ip6po_nextroute.ro_rt) {
2324 			RTFREE(pktopt->ip6po_nextroute.ro_rt);
2325 			pktopt->ip6po_nextroute.ro_rt = NULL;
2326 		}
2327 		if (pktopt->ip6po_nexthop)
2328 			free(pktopt->ip6po_nexthop, M_IP6OPT);
2329 		pktopt->ip6po_nexthop = NULL;
2330 	}
2331 	if (optname == -1 || optname == IPV6_HOPOPTS) {
2332 		if (pktopt->ip6po_hbh)
2333 			free(pktopt->ip6po_hbh, M_IP6OPT);
2334 		pktopt->ip6po_hbh = NULL;
2335 	}
2336 	if (optname == -1 || optname == IPV6_RTHDRDSTOPTS) {
2337 		if (pktopt->ip6po_dest1)
2338 			free(pktopt->ip6po_dest1, M_IP6OPT);
2339 		pktopt->ip6po_dest1 = NULL;
2340 	}
2341 	if (optname == -1 || optname == IPV6_RTHDR) {
2342 		if (pktopt->ip6po_rhinfo.ip6po_rhi_rthdr)
2343 			free(pktopt->ip6po_rhinfo.ip6po_rhi_rthdr, M_IP6OPT);
2344 		pktopt->ip6po_rhinfo.ip6po_rhi_rthdr = NULL;
2345 		if (pktopt->ip6po_route.ro_rt) {
2346 			RTFREE(pktopt->ip6po_route.ro_rt);
2347 			pktopt->ip6po_route.ro_rt = NULL;
2348 		}
2349 	}
2350 	if (optname == -1 || optname == IPV6_DSTOPTS) {
2351 		if (pktopt->ip6po_dest2)
2352 			free(pktopt->ip6po_dest2, M_IP6OPT);
2353 		pktopt->ip6po_dest2 = NULL;
2354 	}
2355 }
2356 
2357 #define PKTOPT_EXTHDRCPY(type) 					\
2358 do {								\
2359 	if (src->type) {					\
2360 		int hlen = (((struct ip6_ext *)src->type)->ip6e_len + 1) << 3;\
2361 		dst->type = malloc(hlen, M_IP6OPT, canwait);	\
2362 		if (dst->type == NULL && canwait == M_NOWAIT)	\
2363 			goto bad;				\
2364 		memcpy(dst->type, src->type, hlen);		\
2365 	}							\
2366 } while (/*CONSTCOND*/ 0)
2367 
2368 static int
2369 copypktopts(struct ip6_pktopts *dst, struct ip6_pktopts *src, int canwait)
2370 {
2371 	dst->ip6po_hlim = src->ip6po_hlim;
2372 	dst->ip6po_tclass = src->ip6po_tclass;
2373 	dst->ip6po_flags = src->ip6po_flags;
2374 	if (src->ip6po_pktinfo) {
2375 		dst->ip6po_pktinfo = malloc(sizeof(*dst->ip6po_pktinfo),
2376 		    M_IP6OPT, canwait);
2377 		if (dst->ip6po_pktinfo == NULL && canwait == M_NOWAIT)
2378 			goto bad;
2379 		*dst->ip6po_pktinfo = *src->ip6po_pktinfo;
2380 	}
2381 	if (src->ip6po_nexthop) {
2382 		dst->ip6po_nexthop = malloc(src->ip6po_nexthop->sa_len,
2383 		    M_IP6OPT, canwait);
2384 		if (dst->ip6po_nexthop == NULL && canwait == M_NOWAIT)
2385 			goto bad;
2386 		memcpy(dst->ip6po_nexthop, src->ip6po_nexthop,
2387 		    src->ip6po_nexthop->sa_len);
2388 	}
2389 	PKTOPT_EXTHDRCPY(ip6po_hbh);
2390 	PKTOPT_EXTHDRCPY(ip6po_dest1);
2391 	PKTOPT_EXTHDRCPY(ip6po_dest2);
2392 	PKTOPT_EXTHDRCPY(ip6po_rthdr); /* not copy the cached route */
2393 	return (0);
2394 
2395   bad:
2396 	if (dst->ip6po_pktinfo) free(dst->ip6po_pktinfo, M_IP6OPT);
2397 	if (dst->ip6po_nexthop) free(dst->ip6po_nexthop, M_IP6OPT);
2398 	if (dst->ip6po_hbh) free(dst->ip6po_hbh, M_IP6OPT);
2399 	if (dst->ip6po_dest1) free(dst->ip6po_dest1, M_IP6OPT);
2400 	if (dst->ip6po_dest2) free(dst->ip6po_dest2, M_IP6OPT);
2401 	if (dst->ip6po_rthdr) free(dst->ip6po_rthdr, M_IP6OPT);
2402 
2403 	return (ENOBUFS);
2404 }
2405 #undef PKTOPT_EXTHDRCPY
2406 
2407 struct ip6_pktopts *
2408 ip6_copypktopts(struct ip6_pktopts *src, int canwait)
2409 {
2410 	int error;
2411 	struct ip6_pktopts *dst;
2412 
2413 	dst = malloc(sizeof(*dst), M_IP6OPT, canwait);
2414 	if (dst == NULL && canwait == M_NOWAIT)
2415 		return (NULL);
2416 	ip6_initpktopts(dst);
2417 
2418 	if ((error = copypktopts(dst, src, canwait)) != 0) {
2419 		free(dst, M_IP6OPT);
2420 		return (NULL);
2421 	}
2422 
2423 	return (dst);
2424 }
2425 
2426 void
2427 ip6_freepcbopts(struct ip6_pktopts *pktopt)
2428 {
2429 	if (pktopt == NULL)
2430 		return;
2431 
2432 	ip6_clearpktopts(pktopt, -1);
2433 
2434 	free(pktopt, M_IP6OPT);
2435 }
2436 
2437 /*
2438  * Set the IP6 multicast options in response to user setsockopt().
2439  */
2440 static int
2441 ip6_setmoptions(optname, im6op, m)
2442 	int optname;
2443 	struct ip6_moptions **im6op;
2444 	struct mbuf *m;
2445 {
2446 	int error = 0;
2447 	u_int loop, ifindex;
2448 	struct ipv6_mreq *mreq;
2449 	struct ifnet *ifp;
2450 	struct ip6_moptions *im6o = *im6op;
2451 	struct route_in6 ro;
2452 	struct in6_multi_mship *imm;
2453 	struct lwp *l = curlwp;	/* XXX */
2454 
2455 	if (im6o == NULL) {
2456 		/*
2457 		 * No multicast option buffer attached to the pcb;
2458 		 * allocate one and initialize to default values.
2459 		 */
2460 		im6o = (struct ip6_moptions *)
2461 			malloc(sizeof(*im6o), M_IPMOPTS, M_WAITOK);
2462 
2463 		if (im6o == NULL)
2464 			return (ENOBUFS);
2465 		*im6op = im6o;
2466 		im6o->im6o_multicast_ifp = NULL;
2467 		im6o->im6o_multicast_hlim = ip6_defmcasthlim;
2468 		im6o->im6o_multicast_loop = IPV6_DEFAULT_MULTICAST_LOOP;
2469 		LIST_INIT(&im6o->im6o_memberships);
2470 	}
2471 
2472 	switch (optname) {
2473 
2474 	case IPV6_MULTICAST_IF:
2475 		/*
2476 		 * Select the interface for outgoing multicast packets.
2477 		 */
2478 		if (m == NULL || m->m_len != sizeof(u_int)) {
2479 			error = EINVAL;
2480 			break;
2481 		}
2482 		bcopy(mtod(m, u_int *), &ifindex, sizeof(ifindex));
2483 		if (ifindex != 0) {
2484 			if (if_indexlim <= ifindex || !ifindex2ifnet[ifindex]) {
2485 				error = ENXIO;	/* XXX EINVAL? */
2486 				break;
2487 			}
2488 			ifp = ifindex2ifnet[ifindex];
2489 			if ((ifp->if_flags & IFF_MULTICAST) == 0) {
2490 				error = EADDRNOTAVAIL;
2491 				break;
2492 			}
2493 		} else
2494 			ifp = NULL;
2495 		im6o->im6o_multicast_ifp = ifp;
2496 		break;
2497 
2498 	case IPV6_MULTICAST_HOPS:
2499 	    {
2500 		/*
2501 		 * Set the IP6 hoplimit for outgoing multicast packets.
2502 		 */
2503 		int optval;
2504 		if (m == NULL || m->m_len != sizeof(int)) {
2505 			error = EINVAL;
2506 			break;
2507 		}
2508 		bcopy(mtod(m, u_int *), &optval, sizeof(optval));
2509 		if (optval < -1 || optval >= 256)
2510 			error = EINVAL;
2511 		else if (optval == -1)
2512 			im6o->im6o_multicast_hlim = ip6_defmcasthlim;
2513 		else
2514 			im6o->im6o_multicast_hlim = optval;
2515 		break;
2516 	    }
2517 
2518 	case IPV6_MULTICAST_LOOP:
2519 		/*
2520 		 * Set the loopback flag for outgoing multicast packets.
2521 		 * Must be zero or one.
2522 		 */
2523 		if (m == NULL || m->m_len != sizeof(u_int)) {
2524 			error = EINVAL;
2525 			break;
2526 		}
2527 		bcopy(mtod(m, u_int *), &loop, sizeof(loop));
2528 		if (loop > 1) {
2529 			error = EINVAL;
2530 			break;
2531 		}
2532 		im6o->im6o_multicast_loop = loop;
2533 		break;
2534 
2535 	case IPV6_JOIN_GROUP:
2536 		/*
2537 		 * Add a multicast group membership.
2538 		 * Group must be a valid IP6 multicast address.
2539 		 */
2540 		if (m == NULL || m->m_len != sizeof(struct ipv6_mreq)) {
2541 			error = EINVAL;
2542 			break;
2543 		}
2544 		mreq = mtod(m, struct ipv6_mreq *);
2545 		if (IN6_IS_ADDR_UNSPECIFIED(&mreq->ipv6mr_multiaddr)) {
2546 			/*
2547 			 * We use the unspecified address to specify to accept
2548 			 * all multicast addresses. Only super user is allowed
2549 			 * to do this.
2550 			 */
2551 			if (kauth_authorize_generic(l->l_cred,
2552 			    KAUTH_GENERIC_ISSUSER, &l->l_acflag))
2553 			{
2554 				error = EACCES;
2555 				break;
2556 			}
2557 		} else if (!IN6_IS_ADDR_MULTICAST(&mreq->ipv6mr_multiaddr)) {
2558 			error = EINVAL;
2559 			break;
2560 		}
2561 
2562 		/*
2563 		 * If no interface was explicitly specified, choose an
2564 		 * appropriate one according to the given multicast address.
2565 		 */
2566 		if (mreq->ipv6mr_interface == 0) {
2567 			struct sockaddr_in6 *dst;
2568 
2569 			/*
2570 			 * Look up the routing table for the
2571 			 * address, and choose the outgoing interface.
2572 			 *   XXX: is it a good approach?
2573 			 */
2574 			ro.ro_rt = NULL;
2575 			dst = (struct sockaddr_in6 *)&ro.ro_dst;
2576 			bzero(dst, sizeof(*dst));
2577 			dst->sin6_family = AF_INET6;
2578 			dst->sin6_len = sizeof(*dst);
2579 			dst->sin6_addr = mreq->ipv6mr_multiaddr;
2580 			rtalloc((struct route *)&ro);
2581 			if (ro.ro_rt == NULL) {
2582 				error = EADDRNOTAVAIL;
2583 				break;
2584 			}
2585 			ifp = ro.ro_rt->rt_ifp;
2586 			rtfree(ro.ro_rt);
2587 		} else {
2588 			/*
2589 			 * If the interface is specified, validate it.
2590 			 */
2591 			if (if_indexlim <= mreq->ipv6mr_interface ||
2592 			    !ifindex2ifnet[mreq->ipv6mr_interface]) {
2593 				error = ENXIO;	/* XXX EINVAL? */
2594 				break;
2595 			}
2596 			ifp = ifindex2ifnet[mreq->ipv6mr_interface];
2597 		}
2598 
2599 		/*
2600 		 * See if we found an interface, and confirm that it
2601 		 * supports multicast
2602 		 */
2603 		if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) {
2604 			error = EADDRNOTAVAIL;
2605 			break;
2606 		}
2607 
2608 		if (in6_setscope(&mreq->ipv6mr_multiaddr, ifp, NULL)) {
2609 			error = EADDRNOTAVAIL; /* XXX: should not happen */
2610 			break;
2611 		}
2612 
2613 		/*
2614 		 * See if the membership already exists.
2615 		 */
2616 		for (imm = im6o->im6o_memberships.lh_first;
2617 		     imm != NULL; imm = imm->i6mm_chain.le_next)
2618 			if (imm->i6mm_maddr->in6m_ifp == ifp &&
2619 			    IN6_ARE_ADDR_EQUAL(&imm->i6mm_maddr->in6m_addr,
2620 			    &mreq->ipv6mr_multiaddr))
2621 				break;
2622 		if (imm != NULL) {
2623 			error = EADDRINUSE;
2624 			break;
2625 		}
2626 		/*
2627 		 * Everything looks good; add a new record to the multicast
2628 		 * address list for the given interface.
2629 		 */
2630 		imm = in6_joingroup(ifp, &mreq->ipv6mr_multiaddr, &error, 0);
2631 		if (imm == NULL)
2632 			break;
2633 		LIST_INSERT_HEAD(&im6o->im6o_memberships, imm, i6mm_chain);
2634 		break;
2635 
2636 	case IPV6_LEAVE_GROUP:
2637 		/*
2638 		 * Drop a multicast group membership.
2639 		 * Group must be a valid IP6 multicast address.
2640 		 */
2641 		if (m == NULL || m->m_len != sizeof(struct ipv6_mreq)) {
2642 			error = EINVAL;
2643 			break;
2644 		}
2645 		mreq = mtod(m, struct ipv6_mreq *);
2646 
2647 		/*
2648 		 * If an interface address was specified, get a pointer
2649 		 * to its ifnet structure.
2650 		 */
2651 		if (mreq->ipv6mr_interface != 0) {
2652 			if (if_indexlim <= mreq->ipv6mr_interface ||
2653 			    !ifindex2ifnet[mreq->ipv6mr_interface]) {
2654 				error = ENXIO;	/* XXX EINVAL? */
2655 				break;
2656 			}
2657 			ifp = ifindex2ifnet[mreq->ipv6mr_interface];
2658 		} else
2659 			ifp = NULL;
2660 
2661 		/* Fill in the scope zone ID */
2662 		if (ifp) {
2663 			if (in6_setscope(&mreq->ipv6mr_multiaddr, ifp, NULL)) {
2664 				/* XXX: should not happen */
2665 				error = EADDRNOTAVAIL;
2666 				break;
2667 			}
2668 		} else if (mreq->ipv6mr_interface != 0) {
2669 			/*
2670 			 * XXX: This case would happens when the (positive)
2671 			 * index is in the valid range, but the corresponding
2672 			 * interface has been detached dynamically.  The above
2673 			 * check probably avoids such case to happen here, but
2674 			 * we check it explicitly for safety.
2675 			 */
2676 			error = EADDRNOTAVAIL;
2677 			break;
2678 		} else {	/* ipv6mr_interface == 0 */
2679 			struct sockaddr_in6 sa6_mc;
2680 
2681 			/*
2682 			 * The API spec says as follows:
2683 			 *  If the interface index is specified as 0, the
2684 			 *  system may choose a multicast group membership to
2685 			 *  drop by matching the multicast address only.
2686 			 * On the other hand, we cannot disambiguate the scope
2687 			 * zone unless an interface is provided.  Thus, we
2688 			 * check if there's ambiguity with the default scope
2689 			 * zone as the last resort.
2690 			 */
2691 			bzero(&sa6_mc, sizeof(sa6_mc));
2692 			sa6_mc.sin6_family = AF_INET6;
2693 			sa6_mc.sin6_len = sizeof(sa6_mc);
2694 			sa6_mc.sin6_addr = mreq->ipv6mr_multiaddr;
2695 			error = sa6_embedscope(&sa6_mc, ip6_use_defzone);
2696 			if (error != 0)
2697 				break;
2698 			mreq->ipv6mr_multiaddr = sa6_mc.sin6_addr;
2699 		}
2700 
2701 		/*
2702 		 * Find the membership in the membership list.
2703 		 */
2704 		for (imm = im6o->im6o_memberships.lh_first;
2705 		     imm != NULL; imm = imm->i6mm_chain.le_next) {
2706 			if ((ifp == NULL || imm->i6mm_maddr->in6m_ifp == ifp) &&
2707 			    IN6_ARE_ADDR_EQUAL(&imm->i6mm_maddr->in6m_addr,
2708 			    &mreq->ipv6mr_multiaddr))
2709 				break;
2710 		}
2711 		if (imm == NULL) {
2712 			/* Unable to resolve interface */
2713 			error = EADDRNOTAVAIL;
2714 			break;
2715 		}
2716 		/*
2717 		 * Give up the multicast address record to which the
2718 		 * membership points.
2719 		 */
2720 		LIST_REMOVE(imm, i6mm_chain);
2721 		in6_leavegroup(imm);
2722 		break;
2723 
2724 	default:
2725 		error = EOPNOTSUPP;
2726 		break;
2727 	}
2728 
2729 	/*
2730 	 * If all options have default values, no need to keep the mbuf.
2731 	 */
2732 	if (im6o->im6o_multicast_ifp == NULL &&
2733 	    im6o->im6o_multicast_hlim == ip6_defmcasthlim &&
2734 	    im6o->im6o_multicast_loop == IPV6_DEFAULT_MULTICAST_LOOP &&
2735 	    im6o->im6o_memberships.lh_first == NULL) {
2736 		free(*im6op, M_IPMOPTS);
2737 		*im6op = NULL;
2738 	}
2739 
2740 	return (error);
2741 }
2742 
2743 /*
2744  * Return the IP6 multicast options in response to user getsockopt().
2745  */
2746 static int
2747 ip6_getmoptions(optname, im6o, mp)
2748 	int optname;
2749 	struct ip6_moptions *im6o;
2750 	struct mbuf **mp;
2751 {
2752 	u_int *hlim, *loop, *ifindex;
2753 
2754 	*mp = m_get(M_WAIT, MT_SOOPTS);
2755 
2756 	switch (optname) {
2757 
2758 	case IPV6_MULTICAST_IF:
2759 		ifindex = mtod(*mp, u_int *);
2760 		(*mp)->m_len = sizeof(u_int);
2761 		if (im6o == NULL || im6o->im6o_multicast_ifp == NULL)
2762 			*ifindex = 0;
2763 		else
2764 			*ifindex = im6o->im6o_multicast_ifp->if_index;
2765 		return (0);
2766 
2767 	case IPV6_MULTICAST_HOPS:
2768 		hlim = mtod(*mp, u_int *);
2769 		(*mp)->m_len = sizeof(u_int);
2770 		if (im6o == NULL)
2771 			*hlim = ip6_defmcasthlim;
2772 		else
2773 			*hlim = im6o->im6o_multicast_hlim;
2774 		return (0);
2775 
2776 	case IPV6_MULTICAST_LOOP:
2777 		loop = mtod(*mp, u_int *);
2778 		(*mp)->m_len = sizeof(u_int);
2779 		if (im6o == NULL)
2780 			*loop = ip6_defmcasthlim;
2781 		else
2782 			*loop = im6o->im6o_multicast_loop;
2783 		return (0);
2784 
2785 	default:
2786 		return (EOPNOTSUPP);
2787 	}
2788 }
2789 
2790 /*
2791  * Discard the IP6 multicast options.
2792  */
2793 void
2794 ip6_freemoptions(im6o)
2795 	struct ip6_moptions *im6o;
2796 {
2797 	struct in6_multi_mship *imm;
2798 
2799 	if (im6o == NULL)
2800 		return;
2801 
2802 	while ((imm = im6o->im6o_memberships.lh_first) != NULL) {
2803 		LIST_REMOVE(imm, i6mm_chain);
2804 		in6_leavegroup(imm);
2805 	}
2806 	free(im6o, M_IPMOPTS);
2807 }
2808 
2809 /*
2810  * Set IPv6 outgoing packet options based on advanced API.
2811  */
2812 int
2813 ip6_setpktopts(control, opt, stickyopt, priv, uproto)
2814 	struct mbuf *control;
2815 	struct ip6_pktopts *opt, *stickyopt;
2816 	int priv, uproto;
2817 {
2818 	struct cmsghdr *cm = 0;
2819 
2820 	if (control == NULL || opt == NULL)
2821 		return (EINVAL);
2822 
2823 	ip6_initpktopts(opt);
2824 	if (stickyopt) {
2825 		int error;
2826 
2827 		/*
2828 		 * If stickyopt is provided, make a local copy of the options
2829 		 * for this particular packet, then override them by ancillary
2830 		 * objects.
2831 		 * XXX: copypktopts() does not copy the cached route to a next
2832 		 * hop (if any).  This is not very good in terms of efficiency,
2833 		 * but we can allow this since this option should be rarely
2834 		 * used.
2835 		 */
2836 		if ((error = copypktopts(opt, stickyopt, M_NOWAIT)) != 0)
2837 			return (error);
2838 	}
2839 
2840 	/*
2841 	 * XXX: Currently, we assume all the optional information is stored
2842 	 * in a single mbuf.
2843 	 */
2844 	if (control->m_next)
2845 		return (EINVAL);
2846 
2847 	for (; control->m_len; control->m_data += CMSG_ALIGN(cm->cmsg_len),
2848 	    control->m_len -= CMSG_ALIGN(cm->cmsg_len)) {
2849 		int error;
2850 
2851 		if (control->m_len < CMSG_LEN(0))
2852 			return (EINVAL);
2853 
2854 		cm = mtod(control, struct cmsghdr *);
2855 		if (cm->cmsg_len == 0 || cm->cmsg_len > control->m_len)
2856 			return (EINVAL);
2857 		if (cm->cmsg_level != IPPROTO_IPV6)
2858 			continue;
2859 
2860 		error = ip6_setpktopt(cm->cmsg_type, CMSG_DATA(cm),
2861 		    cm->cmsg_len - CMSG_LEN(0), opt, priv, 0, 1, uproto);
2862 		if (error)
2863 			return (error);
2864 	}
2865 
2866 	return (0);
2867 }
2868 
2869 /*
2870  * Set a particular packet option, as a sticky option or an ancillary data
2871  * item.  "len" can be 0 only when it's a sticky option.
2872  * We have 4 cases of combination of "sticky" and "cmsg":
2873  * "sticky=0, cmsg=0": impossible
2874  * "sticky=0, cmsg=1": RFC2292 or RFC3542 ancillary data
2875  * "sticky=1, cmsg=0": RFC3542 socket option
2876  * "sticky=1, cmsg=1": RFC2292 socket option
2877  */
2878 static int
2879 ip6_setpktopt(int optname, u_char *buf, int len, struct ip6_pktopts *opt,
2880     int priv, int sticky, int cmsg, int uproto)
2881 {
2882 	int minmtupolicy;
2883 
2884 	if (!sticky && !cmsg) {
2885 #ifdef DIAGNOSTIC
2886 		printf("ip6_setpktopt: impossible case\n");
2887 #endif
2888 		return (EINVAL);
2889 	}
2890 
2891 	/*
2892 	 * IPV6_2292xxx is for backward compatibility to RFC2292, and should
2893 	 * not be specified in the context of RFC3542.  Conversely,
2894 	 * RFC3542 types should not be specified in the context of RFC2292.
2895 	 */
2896 	if (!cmsg) {
2897 		switch (optname) {
2898 		case IPV6_2292PKTINFO:
2899 		case IPV6_2292HOPLIMIT:
2900 		case IPV6_2292NEXTHOP:
2901 		case IPV6_2292HOPOPTS:
2902 		case IPV6_2292DSTOPTS:
2903 		case IPV6_2292RTHDR:
2904 		case IPV6_2292PKTOPTIONS:
2905 			return (ENOPROTOOPT);
2906 		}
2907 	}
2908 	if (sticky && cmsg) {
2909 		switch (optname) {
2910 		case IPV6_PKTINFO:
2911 		case IPV6_HOPLIMIT:
2912 		case IPV6_NEXTHOP:
2913 		case IPV6_HOPOPTS:
2914 		case IPV6_DSTOPTS:
2915 		case IPV6_RTHDRDSTOPTS:
2916 		case IPV6_RTHDR:
2917 		case IPV6_USE_MIN_MTU:
2918 		case IPV6_DONTFRAG:
2919 		case IPV6_OTCLASS:
2920 		case IPV6_TCLASS:
2921 			return (ENOPROTOOPT);
2922 		}
2923 	}
2924 
2925 	switch (optname) {
2926 #ifdef RFC2292
2927 	case IPV6_2292PKTINFO:
2928 #endif
2929 	case IPV6_PKTINFO:
2930 	{
2931 		struct ifnet *ifp = NULL;
2932 		struct in6_pktinfo *pktinfo;
2933 
2934 		if (len != sizeof(struct in6_pktinfo))
2935 			return (EINVAL);
2936 
2937 		pktinfo = (struct in6_pktinfo *)buf;
2938 
2939 		/*
2940 		 * An application can clear any sticky IPV6_PKTINFO option by
2941 		 * doing a "regular" setsockopt with ipi6_addr being
2942 		 * in6addr_any and ipi6_ifindex being zero.
2943 		 * [RFC 3542, Section 6]
2944 		 */
2945 		if (optname == IPV6_PKTINFO && opt->ip6po_pktinfo &&
2946 		    pktinfo->ipi6_ifindex == 0 &&
2947 		    IN6_IS_ADDR_UNSPECIFIED(&pktinfo->ipi6_addr)) {
2948 			ip6_clearpktopts(opt, optname);
2949 			break;
2950 		}
2951 
2952 		if (uproto == IPPROTO_TCP && optname == IPV6_PKTINFO &&
2953 		    sticky && !IN6_IS_ADDR_UNSPECIFIED(&pktinfo->ipi6_addr)) {
2954 			return (EINVAL);
2955 		}
2956 
2957 		/* validate the interface index if specified. */
2958 		if (pktinfo->ipi6_ifindex >= if_indexlim) {
2959 			 return (ENXIO);
2960 		}
2961 		if (pktinfo->ipi6_ifindex) {
2962 			ifp = ifindex2ifnet[pktinfo->ipi6_ifindex];
2963 			if (ifp == NULL)
2964 				return (ENXIO);
2965 		}
2966 
2967 		/*
2968 		 * We store the address anyway, and let in6_selectsrc()
2969 		 * validate the specified address.  This is because ipi6_addr
2970 		 * may not have enough information about its scope zone, and
2971 		 * we may need additional information (such as outgoing
2972 		 * interface or the scope zone of a destination address) to
2973 		 * disambiguate the scope.
2974 		 * XXX: the delay of the validation may confuse the
2975 		 * application when it is used as a sticky option.
2976 		 */
2977 		if (opt->ip6po_pktinfo == NULL) {
2978 			opt->ip6po_pktinfo = malloc(sizeof(*pktinfo),
2979 			    M_IP6OPT, M_NOWAIT);
2980 			if (opt->ip6po_pktinfo == NULL)
2981 				return (ENOBUFS);
2982 		}
2983 		memcpy(opt->ip6po_pktinfo, pktinfo, sizeof(*pktinfo));
2984 		break;
2985 	}
2986 
2987 #ifdef RFC2292
2988 	case IPV6_2292HOPLIMIT:
2989 #endif
2990 	case IPV6_HOPLIMIT:
2991 	{
2992 		int *hlimp;
2993 
2994 		/*
2995 		 * RFC 3542 deprecated the usage of sticky IPV6_HOPLIMIT
2996 		 * to simplify the ordering among hoplimit options.
2997 		 */
2998 		if (optname == IPV6_HOPLIMIT && sticky)
2999 			return (ENOPROTOOPT);
3000 
3001 		if (len != sizeof(int))
3002 			return (EINVAL);
3003 		hlimp = (int *)buf;
3004 		if (*hlimp < -1 || *hlimp > 255)
3005 			return (EINVAL);
3006 
3007 		opt->ip6po_hlim = *hlimp;
3008 		break;
3009 	}
3010 
3011 	case IPV6_OTCLASS:
3012 		if (len != sizeof(u_int8_t))
3013 			return (EINVAL);
3014 
3015 		opt->ip6po_tclass = *(u_int8_t *)buf;
3016 		break;
3017 
3018 	case IPV6_TCLASS:
3019 	{
3020 		int tclass;
3021 
3022 		if (len != sizeof(int))
3023 			return (EINVAL);
3024 		tclass = *(int *)buf;
3025 		if (tclass < -1 || tclass > 255)
3026 			return (EINVAL);
3027 
3028 		opt->ip6po_tclass = tclass;
3029 		break;
3030 	}
3031 
3032 #ifdef RFC2292
3033 	case IPV6_2292NEXTHOP:
3034 #endif
3035 	case IPV6_NEXTHOP:
3036 		if (!priv)
3037 			return (EPERM);
3038 
3039 		if (len == 0) {	/* just remove the option */
3040 			ip6_clearpktopts(opt, IPV6_NEXTHOP);
3041 			break;
3042 		}
3043 
3044 		/* check if cmsg_len is large enough for sa_len */
3045 		if (len < sizeof(struct sockaddr) || len < *buf)
3046 			return (EINVAL);
3047 
3048 		switch (((struct sockaddr *)buf)->sa_family) {
3049 		case AF_INET6:
3050 		{
3051 			struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)buf;
3052 			int error;
3053 
3054 			if (sa6->sin6_len != sizeof(struct sockaddr_in6))
3055 				return (EINVAL);
3056 
3057 			if (IN6_IS_ADDR_UNSPECIFIED(&sa6->sin6_addr) ||
3058 			    IN6_IS_ADDR_MULTICAST(&sa6->sin6_addr)) {
3059 				return (EINVAL);
3060 			}
3061 			if ((error = sa6_embedscope(sa6, ip6_use_defzone))
3062 			    != 0) {
3063 				return (error);
3064 			}
3065 			break;
3066 		}
3067 		case AF_LINK:	/* eventually be supported? */
3068 		default:
3069 			return (EAFNOSUPPORT);
3070 		}
3071 
3072 		/* turn off the previous option, then set the new option. */
3073 		ip6_clearpktopts(opt, IPV6_NEXTHOP);
3074 		opt->ip6po_nexthop = malloc(*buf, M_IP6OPT, M_NOWAIT);
3075 		if (opt->ip6po_nexthop == NULL)
3076 			return (ENOBUFS);
3077 		memcpy(opt->ip6po_nexthop, buf, *buf);
3078 		break;
3079 
3080 #ifdef RFC2292
3081 	case IPV6_2292HOPOPTS:
3082 #endif
3083 	case IPV6_HOPOPTS:
3084 	{
3085 		struct ip6_hbh *hbh;
3086 		int hbhlen;
3087 
3088 		/*
3089 		 * XXX: We don't allow a non-privileged user to set ANY HbH
3090 		 * options, since per-option restriction has too much
3091 		 * overhead.
3092 		 */
3093 		if (!priv)
3094 			return (EPERM);
3095 
3096 		if (len == 0) {
3097 			ip6_clearpktopts(opt, IPV6_HOPOPTS);
3098 			break;	/* just remove the option */
3099 		}
3100 
3101 		/* message length validation */
3102 		if (len < sizeof(struct ip6_hbh))
3103 			return (EINVAL);
3104 		hbh = (struct ip6_hbh *)buf;
3105 		hbhlen = (hbh->ip6h_len + 1) << 3;
3106 		if (len != hbhlen)
3107 			return (EINVAL);
3108 
3109 		/* turn off the previous option, then set the new option. */
3110 		ip6_clearpktopts(opt, IPV6_HOPOPTS);
3111 		opt->ip6po_hbh = malloc(hbhlen, M_IP6OPT, M_NOWAIT);
3112 		if (opt->ip6po_hbh == NULL)
3113 			return (ENOBUFS);
3114 		memcpy(opt->ip6po_hbh, hbh, hbhlen);
3115 
3116 		break;
3117 	}
3118 
3119 #ifdef RFC2292
3120 	case IPV6_2292DSTOPTS:
3121 #endif
3122 	case IPV6_DSTOPTS:
3123 	case IPV6_RTHDRDSTOPTS:
3124 	{
3125 		struct ip6_dest *dest, **newdest = NULL;
3126 		int destlen;
3127 
3128 		if (!priv)	/* XXX: see the comment for IPV6_HOPOPTS */
3129 			return (EPERM);
3130 
3131 		if (len == 0) {
3132 			ip6_clearpktopts(opt, optname);
3133 			break;	/* just remove the option */
3134 		}
3135 
3136 		/* message length validation */
3137 		if (len < sizeof(struct ip6_dest))
3138 			return (EINVAL);
3139 		dest = (struct ip6_dest *)buf;
3140 		destlen = (dest->ip6d_len + 1) << 3;
3141 		if (len != destlen)
3142 			return (EINVAL);
3143 		/*
3144 		 * Determine the position that the destination options header
3145 		 * should be inserted; before or after the routing header.
3146 		 */
3147 		switch (optname) {
3148 		case IPV6_2292DSTOPTS:
3149 			/*
3150 			 * The old advanced API is ambiguous on this point.
3151 			 * Our approach is to determine the position based
3152 			 * according to the existence of a routing header.
3153 			 * Note, however, that this depends on the order of the
3154 			 * extension headers in the ancillary data; the 1st
3155 			 * part of the destination options header must appear
3156 			 * before the routing header in the ancillary data,
3157 			 * too.
3158 			 * RFC3542 solved the ambiguity by introducing
3159 			 * separate ancillary data or option types.
3160 			 */
3161 			if (opt->ip6po_rthdr == NULL)
3162 				newdest = &opt->ip6po_dest1;
3163 			else
3164 				newdest = &opt->ip6po_dest2;
3165 			break;
3166 		case IPV6_RTHDRDSTOPTS:
3167 			newdest = &opt->ip6po_dest1;
3168 			break;
3169 		case IPV6_DSTOPTS:
3170 			newdest = &opt->ip6po_dest2;
3171 			break;
3172 		}
3173 
3174 		/* turn off the previous option, then set the new option. */
3175 		ip6_clearpktopts(opt, optname);
3176 		*newdest = malloc(destlen, M_IP6OPT, M_NOWAIT);
3177 		if (*newdest == NULL)
3178 			return (ENOBUFS);
3179 		memcpy(*newdest, dest, destlen);
3180 
3181 		break;
3182 	}
3183 
3184 #ifdef RFC2292
3185 	case IPV6_2292RTHDR:
3186 #endif
3187 	case IPV6_RTHDR:
3188 	{
3189 		struct ip6_rthdr *rth;
3190 		int rthlen;
3191 
3192 		if (len == 0) {
3193 			ip6_clearpktopts(opt, IPV6_RTHDR);
3194 			break;	/* just remove the option */
3195 		}
3196 
3197 		/* message length validation */
3198 		if (len < sizeof(struct ip6_rthdr))
3199 			return (EINVAL);
3200 		rth = (struct ip6_rthdr *)buf;
3201 		rthlen = (rth->ip6r_len + 1) << 3;
3202 		if (len != rthlen)
3203 			return (EINVAL);
3204 		switch (rth->ip6r_type) {
3205 		case IPV6_RTHDR_TYPE_0:
3206 			if (rth->ip6r_len == 0)	/* must contain one addr */
3207 				return (EINVAL);
3208 			if (rth->ip6r_len % 2) /* length must be even */
3209 				return (EINVAL);
3210 			if (rth->ip6r_len / 2 != rth->ip6r_segleft)
3211 				return (EINVAL);
3212 			break;
3213 		default:
3214 			return (EINVAL);	/* not supported */
3215 		}
3216 		/* turn off the previous option */
3217 		ip6_clearpktopts(opt, IPV6_RTHDR);
3218 		opt->ip6po_rthdr = malloc(rthlen, M_IP6OPT, M_NOWAIT);
3219 		if (opt->ip6po_rthdr == NULL)
3220 			return (ENOBUFS);
3221 		memcpy(opt->ip6po_rthdr, rth, rthlen);
3222 		break;
3223 	}
3224 
3225 	case IPV6_USE_MIN_MTU:
3226 		if (len != sizeof(int))
3227 			return (EINVAL);
3228 		minmtupolicy = *(int *)buf;
3229 		if (minmtupolicy != IP6PO_MINMTU_MCASTONLY &&
3230 		    minmtupolicy != IP6PO_MINMTU_DISABLE &&
3231 		    minmtupolicy != IP6PO_MINMTU_ALL) {
3232 			return (EINVAL);
3233 		}
3234 		opt->ip6po_minmtu = minmtupolicy;
3235 		break;
3236 
3237 	case IPV6_DONTFRAG:
3238 		if (len != sizeof(int))
3239 			return (EINVAL);
3240 
3241 		if (uproto == IPPROTO_TCP || *(int *)buf == 0) {
3242 			/*
3243 			 * we ignore this option for TCP sockets.
3244 			 * (RFC3542 leaves this case unspecified.)
3245 			 */
3246 			opt->ip6po_flags &= ~IP6PO_DONTFRAG;
3247 		} else
3248 			opt->ip6po_flags |= IP6PO_DONTFRAG;
3249 		break;
3250 
3251 	default:
3252 		return (ENOPROTOOPT);
3253 	} /* end of switch */
3254 
3255 	return (0);
3256 }
3257 
3258 /*
3259  * Routine called from ip6_output() to loop back a copy of an IP6 multicast
3260  * packet to the input queue of a specified interface.  Note that this
3261  * calls the output routine of the loopback "driver", but with an interface
3262  * pointer that might NOT be lo0ifp -- easier than replicating that code here.
3263  */
3264 void
3265 ip6_mloopback(ifp, m, dst)
3266 	struct ifnet *ifp;
3267 	struct mbuf *m;
3268 	struct sockaddr_in6 *dst;
3269 {
3270 	struct mbuf *copym;
3271 	struct ip6_hdr *ip6;
3272 
3273 	copym = m_copy(m, 0, M_COPYALL);
3274 	if (copym == NULL)
3275 		return;
3276 
3277 	/*
3278 	 * Make sure to deep-copy IPv6 header portion in case the data
3279 	 * is in an mbuf cluster, so that we can safely override the IPv6
3280 	 * header portion later.
3281 	 */
3282 	if ((copym->m_flags & M_EXT) != 0 ||
3283 	    copym->m_len < sizeof(struct ip6_hdr)) {
3284 		copym = m_pullup(copym, sizeof(struct ip6_hdr));
3285 		if (copym == NULL)
3286 			return;
3287 	}
3288 
3289 #ifdef DIAGNOSTIC
3290 	if (copym->m_len < sizeof(*ip6)) {
3291 		m_freem(copym);
3292 		return;
3293 	}
3294 #endif
3295 
3296 	ip6 = mtod(copym, struct ip6_hdr *);
3297 	/*
3298 	 * clear embedded scope identifiers if necessary.
3299 	 * in6_clearscope will touch the addresses only when necessary.
3300 	 */
3301 	in6_clearscope(&ip6->ip6_src);
3302 	in6_clearscope(&ip6->ip6_dst);
3303 
3304 	(void)looutput(ifp, copym, (struct sockaddr *)dst, NULL);
3305 }
3306 
3307 /*
3308  * Chop IPv6 header off from the payload.
3309  */
3310 static int
3311 ip6_splithdr(m, exthdrs)
3312 	struct mbuf *m;
3313 	struct ip6_exthdrs *exthdrs;
3314 {
3315 	struct mbuf *mh;
3316 	struct ip6_hdr *ip6;
3317 
3318 	ip6 = mtod(m, struct ip6_hdr *);
3319 	if (m->m_len > sizeof(*ip6)) {
3320 		MGETHDR(mh, M_DONTWAIT, MT_HEADER);
3321 		if (mh == 0) {
3322 			m_freem(m);
3323 			return ENOBUFS;
3324 		}
3325 		M_MOVE_PKTHDR(mh, m);
3326 		MH_ALIGN(mh, sizeof(*ip6));
3327 		m->m_len -= sizeof(*ip6);
3328 		m->m_data += sizeof(*ip6);
3329 		mh->m_next = m;
3330 		m = mh;
3331 		m->m_len = sizeof(*ip6);
3332 		bcopy((caddr_t)ip6, mtod(m, caddr_t), sizeof(*ip6));
3333 	}
3334 	exthdrs->ip6e_ip6 = m;
3335 	return 0;
3336 }
3337 
3338 /*
3339  * Compute IPv6 extension header length.
3340  */
3341 int
3342 ip6_optlen(in6p)
3343 	struct in6pcb *in6p;
3344 {
3345 	int len;
3346 
3347 	if (!in6p->in6p_outputopts)
3348 		return 0;
3349 
3350 	len = 0;
3351 #define elen(x) \
3352     (((struct ip6_ext *)(x)) ? (((struct ip6_ext *)(x))->ip6e_len + 1) << 3 : 0)
3353 
3354 	len += elen(in6p->in6p_outputopts->ip6po_hbh);
3355 	len += elen(in6p->in6p_outputopts->ip6po_dest1);
3356 	len += elen(in6p->in6p_outputopts->ip6po_rthdr);
3357 	len += elen(in6p->in6p_outputopts->ip6po_dest2);
3358 	return len;
3359 #undef elen
3360 }
3361