xref: /dragonfly/sys/netinet6/ip6_output.c (revision bc3d4063)
1 /*	$FreeBSD: src/sys/netinet6/ip6_output.c,v 1.13.2.18 2003/01/24 05:11:35 sam Exp $	*/
2 /*	$DragonFly: src/sys/netinet6/ip6_output.c,v 1.36 2008/06/18 11:38:37 swildner Exp $	*/
3 /*	$KAME: ip6_output.c,v 1.279 2002/01/26 06:12:30 jinmei Exp $	*/
4 
5 /*
6  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. Neither the name of the project nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 /*
35  * Copyright (c) 1982, 1986, 1988, 1990, 1993
36  *	The Regents of the University of California.  All rights reserved.
37  *
38  * Redistribution and use in source and binary forms, with or without
39  * modification, are permitted provided that the following conditions
40  * are met:
41  * 1. Redistributions of source code must retain the above copyright
42  *    notice, this list of conditions and the following disclaimer.
43  * 2. Redistributions in binary form must reproduce the above copyright
44  *    notice, this list of conditions and the following disclaimer in the
45  *    documentation and/or other materials provided with the distribution.
46  * 3. All advertising materials mentioning features or use of this software
47  *    must display the following acknowledgement:
48  *	This product includes software developed by the University of
49  *	California, Berkeley and its contributors.
50  * 4. Neither the name of the University nor the names of its contributors
51  *    may be used to endorse or promote products derived from this software
52  *    without specific prior written permission.
53  *
54  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
55  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
56  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
57  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
58  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
59  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
60  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
61  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
62  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
63  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
64  * SUCH DAMAGE.
65  *
66  *	@(#)ip_output.c	8.3 (Berkeley) 1/21/94
67  */
68 
69 #include "opt_ip6fw.h"
70 #include "opt_inet.h"
71 #include "opt_inet6.h"
72 #include "opt_ipsec.h"
73 
74 #include <sys/param.h>
75 #include <sys/malloc.h>
76 #include <sys/mbuf.h>
77 #include <sys/errno.h>
78 #include <sys/protosw.h>
79 #include <sys/socket.h>
80 #include <sys/socketvar.h>
81 #include <sys/systm.h>
82 #include <sys/kernel.h>
83 #include <sys/proc.h>
84 
85 #include <net/if.h>
86 #include <net/route.h>
87 #include <net/pfil.h>
88 
89 #include <netinet/in.h>
90 #include <netinet/in_var.h>
91 #include <netinet6/in6_var.h>
92 #include <netinet/ip6.h>
93 #include <netinet/icmp6.h>
94 #include <netinet6/ip6_var.h>
95 #include <netinet/in_pcb.h>
96 #include <netinet6/nd6.h>
97 
98 #ifdef IPSEC
99 #include <netinet6/ipsec.h>
100 #ifdef INET6
101 #include <netinet6/ipsec6.h>
102 #endif
103 #include <netproto/key/key.h>
104 #endif /* IPSEC */
105 
106 #ifdef FAST_IPSEC
107 #include <netproto/ipsec/ipsec.h>
108 #include <netproto/ipsec/ipsec6.h>
109 #include <netproto/ipsec/key.h>
110 #endif
111 
112 #include <net/ip6fw/ip6_fw.h>
113 
114 #include <net/net_osdep.h>
115 
116 static MALLOC_DEFINE(M_IPMOPTS, "ip6_moptions", "internet multicast options");
117 
118 struct ip6_exthdrs {
119 	struct mbuf *ip6e_ip6;
120 	struct mbuf *ip6e_hbh;
121 	struct mbuf *ip6e_dest1;
122 	struct mbuf *ip6e_rthdr;
123 	struct mbuf *ip6e_dest2;
124 };
125 
126 static int ip6_pcbopts (struct ip6_pktopts **, struct mbuf *,
127 			    struct socket *, struct sockopt *sopt);
128 static int ip6_setmoptions (int, struct ip6_moptions **, struct mbuf *);
129 static int ip6_getmoptions (int, struct ip6_moptions *, struct mbuf **);
130 static int copyexthdr (void *, struct mbuf **);
131 static int ip6_insertfraghdr (struct mbuf *, struct mbuf *, int,
132 				  struct ip6_frag **);
133 static int ip6_insert_jumboopt (struct ip6_exthdrs *, u_int32_t);
134 static struct mbuf *ip6_splithdr (struct mbuf *);
135 
136 /*
137  * IP6 output. The packet in mbuf chain m contains a skeletal IP6
138  * header (with pri, len, nxt, hlim, src, dst).
139  * This function may modify ver and hlim only.
140  * The mbuf chain containing the packet will be freed.
141  * The mbuf opt, if present, will not be freed.
142  *
143  * type of "mtu": rt_rmx.rmx_mtu is u_long, ifnet.ifr_mtu is int, and
144  * nd_ifinfo.linkmtu is u_int32_t.  so we use u_long to hold largest one,
145  * which is rt_rmx.rmx_mtu.
146  */
147 int
148 ip6_output(struct mbuf *m0, struct ip6_pktopts *opt, struct route_in6 *ro,
149 	   int flags, struct ip6_moptions *im6o,
150 	   struct ifnet **ifpp,		/* XXX: just for statistics */
151 	   struct inpcb *inp)
152 {
153 	struct ip6_hdr *ip6, *mhip6;
154 	struct ifnet *ifp, *origifp;
155 	struct mbuf *m = m0;
156 	struct mbuf *mprev;
157 	u_char *nexthdrp;
158 	int hlen, tlen, len, off;
159 	struct route_in6 ip6route;
160 	struct sockaddr_in6 *dst;
161 	int error = 0;
162 	struct in6_ifaddr *ia = NULL;
163 	u_long mtu;
164 	u_int32_t optlen, plen = 0, unfragpartlen;
165 	struct ip6_exthdrs exthdrs;
166 	struct in6_addr finaldst;
167 	struct route_in6 *ro_pmtu = NULL;
168 	boolean_t hdrsplit = FALSE;
169 	boolean_t needipsec = FALSE;
170 #ifdef IPSEC
171 	boolean_t needipsectun = FALSE;
172 	struct secpolicy *sp = NULL;
173 	struct socket *so = inp ? inp->inp_socket : NULL;
174 
175 	ip6 = mtod(m, struct ip6_hdr *);
176 #endif
177 #ifdef FAST_IPSEC
178 	boolean_t needipsectun = FALSE;
179 	struct secpolicy *sp = NULL;
180 
181 	ip6 = mtod(m, struct ip6_hdr *);
182 #endif
183 
184 	bzero(&exthdrs, sizeof exthdrs);
185 
186 	if (opt) {
187 		if ((error = copyexthdr(opt->ip6po_hbh, &exthdrs.ip6e_hbh)))
188 			goto freehdrs;
189 		if ((error = copyexthdr(opt->ip6po_dest1, &exthdrs.ip6e_dest1)))
190 			goto freehdrs;
191 		if ((error = copyexthdr(opt->ip6po_rthdr, &exthdrs.ip6e_rthdr)))
192 			goto freehdrs;
193 		if ((error = copyexthdr(opt->ip6po_dest2, &exthdrs.ip6e_dest2)))
194 			goto freehdrs;
195 	}
196 
197 #ifdef IPSEC
198 	/* get a security policy for this packet */
199 	if (so == NULL)
200 		sp = ipsec6_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, 0, &error);
201 	else
202 		sp = ipsec6_getpolicybysock(m, IPSEC_DIR_OUTBOUND, so, &error);
203 
204 	if (sp == NULL) {
205 		ipsec6stat.out_inval++;
206 		goto freehdrs;
207 	}
208 
209 	error = 0;
210 
211 	/* check policy */
212 	switch (sp->policy) {
213 	case IPSEC_POLICY_DISCARD:
214 		/*
215 		 * This packet is just discarded.
216 		 */
217 		ipsec6stat.out_polvio++;
218 		goto freehdrs;
219 
220 	case IPSEC_POLICY_BYPASS:
221 	case IPSEC_POLICY_NONE:
222 		/* no need to do IPsec. */
223 		needipsec = FALSE;
224 		break;
225 
226 	case IPSEC_POLICY_IPSEC:
227 		if (sp->req == NULL) {
228 			error = key_spdacquire(sp);	/* acquire a policy */
229 			goto freehdrs;
230 		}
231 		needipsec = TRUE;
232 		break;
233 
234 	case IPSEC_POLICY_ENTRUST:
235 	default:
236 		kprintf("ip6_output: Invalid policy found. %d\n", sp->policy);
237 	}
238 #endif /* IPSEC */
239 #ifdef FAST_IPSEC
240 	/* get a security policy for this packet */
241 	if (inp == NULL)
242 		sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, 0, &error);
243 	else
244 		sp = ipsec_getpolicybysock(m, IPSEC_DIR_OUTBOUND, inp, &error);
245 
246 	if (sp == NULL) {
247 		newipsecstat.ips_out_inval++;
248 		goto freehdrs;
249 	}
250 
251 	error = 0;
252 
253 	/* check policy */
254 	switch (sp->policy) {
255 	case IPSEC_POLICY_DISCARD:
256 		/*
257 		 * This packet is just discarded.
258 		 */
259 		newipsecstat.ips_out_polvio++;
260 		goto freehdrs;
261 
262 	case IPSEC_POLICY_BYPASS:
263 	case IPSEC_POLICY_NONE:
264 		/* no need to do IPsec. */
265 		needipsec = FALSE;
266 		break;
267 
268 	case IPSEC_POLICY_IPSEC:
269 		if (sp->req == NULL) {
270 			error = key_spdacquire(sp);	/* acquire a policy */
271 			goto freehdrs;
272 		}
273 		needipsec = TRUE;
274 		break;
275 
276 	case IPSEC_POLICY_ENTRUST:
277 	default:
278 		kprintf("ip6_output: Invalid policy found. %d\n", sp->policy);
279 	}
280 #endif /* FAST_IPSEC */
281 
282 	/*
283 	 * Calculate the total length of the extension header chain.
284 	 * Keep the length of the unfragmentable part for fragmentation.
285 	 */
286 	optlen = m_lengthm(exthdrs.ip6e_hbh, NULL) +
287 	    m_lengthm(exthdrs.ip6e_dest1, NULL) +
288 	    m_lengthm(exthdrs.ip6e_rthdr, NULL);
289 
290 	unfragpartlen = optlen + sizeof(struct ip6_hdr);
291 
292 	/* NOTE: we don't add AH/ESP length here. do that later. */
293 	optlen += m_lengthm(exthdrs.ip6e_dest2, NULL);
294 
295 	/*
296 	 * If we need IPsec, or there is at least one extension header,
297 	 * separate IP6 header from the payload.
298 	 */
299 	if ((needipsec || optlen) && !hdrsplit) {
300 		exthdrs.ip6e_ip6 = ip6_splithdr(m);
301 		if (exthdrs.ip6e_ip6 == NULL) {
302 			error = ENOBUFS;
303 			goto freehdrs;
304 		}
305 		m = exthdrs.ip6e_ip6;
306 		hdrsplit = TRUE;
307 	}
308 
309 	/* adjust pointer */
310 	ip6 = mtod(m, struct ip6_hdr *);
311 
312 	/* adjust mbuf packet header length */
313 	m->m_pkthdr.len += optlen;
314 	plen = m->m_pkthdr.len - sizeof(*ip6);
315 
316 	/* If this is a jumbo payload, insert a jumbo payload option. */
317 	if (plen > IPV6_MAXPACKET) {
318 		if (!hdrsplit) {
319 			exthdrs.ip6e_ip6 = ip6_splithdr(m);
320 			if (exthdrs.ip6e_ip6 == NULL) {
321 				error = ENOBUFS;
322 				goto freehdrs;
323 			}
324 			m = exthdrs.ip6e_ip6;
325 			hdrsplit = TRUE;
326 		}
327 		/* adjust pointer */
328 		ip6 = mtod(m, struct ip6_hdr *);
329 		if ((error = ip6_insert_jumboopt(&exthdrs, plen)) != 0)
330 			goto freehdrs;
331 		ip6->ip6_plen = 0;
332 	} else
333 		ip6->ip6_plen = htons(plen);
334 
335 	/*
336 	 * Concatenate headers and fill in next header fields.
337 	 * Here we have, on "m"
338 	 *	IPv6 payload
339 	 * and we insert headers accordingly.  Finally, we should be getting:
340 	 *	IPv6 hbh dest1 rthdr ah* [esp* dest2 payload]
341 	 *
342 	 * during the header composing process, "m" points to IPv6 header.
343 	 * "mprev" points to an extension header prior to esp.
344 	 */
345 
346 	nexthdrp = &ip6->ip6_nxt;
347 	mprev = m;
348 
349 	/*
350 	 * we treat dest2 specially.  this makes IPsec processing
351 	 * much easier.  the goal here is to make mprev point the
352 	 * mbuf prior to dest2.
353 	 *
354 	 * result: IPv6 dest2 payload
355 	 * m and mprev will point to IPv6 header.
356 	 */
357 	if (exthdrs.ip6e_dest2) {
358 		if (!hdrsplit)
359 			panic("assumption failed: hdr not split");
360 		exthdrs.ip6e_dest2->m_next = m->m_next;
361 		m->m_next = exthdrs.ip6e_dest2;
362 		*mtod(exthdrs.ip6e_dest2, u_char *) = ip6->ip6_nxt;
363 		ip6->ip6_nxt = IPPROTO_DSTOPTS;
364 	}
365 
366 /*
367  * Place m1 after mprev.
368  */
369 #define MAKE_CHAIN(m1, mprev, nexthdrp, i)\
370     do {\
371 	if (m1) {\
372 		if (!hdrsplit)\
373 			panic("assumption failed: hdr not split");\
374 		*mtod(m1, u_char *) = *nexthdrp;\
375 		*nexthdrp = (i);\
376 		nexthdrp = mtod(m1, u_char *);\
377 		m1->m_next = mprev->m_next;\
378 		mprev->m_next = m1;\
379 		mprev = m1;\
380 	}\
381     } while (0)
382 
383 	/*
384 	 * result: IPv6 hbh dest1 rthdr dest2 payload
385 	 * m will point to IPv6 header.  mprev will point to the
386 	 * extension header prior to dest2 (rthdr in the above case).
387 	 */
388 	MAKE_CHAIN(exthdrs.ip6e_hbh, mprev, nexthdrp, IPPROTO_HOPOPTS);
389 	MAKE_CHAIN(exthdrs.ip6e_dest1, mprev, nexthdrp, IPPROTO_DSTOPTS);
390 	MAKE_CHAIN(exthdrs.ip6e_rthdr, mprev, nexthdrp, IPPROTO_ROUTING);
391 
392 #if defined(IPSEC) || defined(FAST_IPSEC)
393 	if (needipsec) {
394 		struct ipsec_output_state state;
395 		int segleft_org = 0;
396 		struct ip6_rthdr *rh = NULL;
397 
398 		/*
399 		 * pointers after IPsec headers are not valid any more.
400 		 * other pointers need a great care too.
401 		 * (IPsec routines should not mangle mbufs prior to AH/ESP)
402 		 */
403 		exthdrs.ip6e_dest2 = NULL;
404 
405 		if (exthdrs.ip6e_rthdr) {
406 			rh = mtod(exthdrs.ip6e_rthdr, struct ip6_rthdr *);
407 			segleft_org = rh->ip6r_segleft;
408 			rh->ip6r_segleft = 0;
409 		}
410 
411 		bzero(&state, sizeof state);
412 		state.m = m;
413 		error = ipsec6_output_trans(&state, nexthdrp, mprev, sp, flags,
414 					    &needipsectun);
415 		m = state.m;
416 		if (error) {
417 			/* mbuf is already reclaimed in ipsec6_output_trans. */
418 			m = NULL;
419 			switch (error) {
420 			case EHOSTUNREACH:
421 			case ENETUNREACH:
422 			case EMSGSIZE:
423 			case ENOBUFS:
424 			case ENOMEM:
425 				break;
426 			default:
427 				kprintf("ip6_output (ipsec): error code %d\n",
428 				       error);
429 				/* fall through */
430 			case ENOENT:
431 				/* don't show these error codes to the user */
432 				error = 0;
433 				break;
434 			}
435 			goto bad;
436 		}
437 		if (exthdrs.ip6e_rthdr) {
438 			/* ah6_output doesn't modify mbuf chain */
439 			rh->ip6r_segleft = segleft_org;
440 		}
441 	}
442 #endif
443 
444 	/*
445 	 * If there is a routing header, replace destination address field
446 	 * with the first hop of the routing header.
447 	 */
448 	if (exthdrs.ip6e_rthdr) {
449 		struct ip6_rthdr *rh;
450 		struct ip6_rthdr0 *rh0;
451 
452 		finaldst = ip6->ip6_dst;
453 		rh = mtod(exthdrs.ip6e_rthdr, struct ip6_rthdr *);
454 		switch (rh->ip6r_type) {
455 		case IPV6_RTHDR_TYPE_0:
456 			 rh0 = (struct ip6_rthdr0 *)rh;
457 			 ip6->ip6_dst = rh0->ip6r0_addr[0];
458 			 bcopy(&rh0->ip6r0_addr[1], &rh0->ip6r0_addr[0],
459 			     sizeof(struct in6_addr)*(rh0->ip6r0_segleft - 1));
460 			 rh0->ip6r0_addr[rh0->ip6r0_segleft - 1] = finaldst;
461 			 break;
462 		default:	/* is it possible? */
463 			 error = EINVAL;
464 			 goto bad;
465 		}
466 	}
467 
468 	/* Source address validation */
469 	if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) &&
470 	    !(flags & IPV6_DADOUTPUT)) {
471 		error = EOPNOTSUPP;
472 		ip6stat.ip6s_badscope++;
473 		goto bad;
474 	}
475 	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_src)) {
476 		error = EOPNOTSUPP;
477 		ip6stat.ip6s_badscope++;
478 		goto bad;
479 	}
480 
481 	ip6stat.ip6s_localout++;
482 
483 	/*
484 	 * Route packet.
485 	 */
486 	if (ro == NULL) {
487 		ro = &ip6route;
488 		bzero(ro, sizeof(*ro));
489 	}
490 	ro_pmtu = ro;
491 	if (opt && opt->ip6po_rthdr)
492 		ro = &opt->ip6po_route;
493 	dst = (struct sockaddr_in6 *)&ro->ro_dst;
494 	/*
495 	 * If there is a cached route,
496 	 * check that it is to the same destination
497 	 * and is still up. If not, free it and try again.
498 	 */
499 	if (ro->ro_rt != NULL &&
500 	    (!(ro->ro_rt->rt_flags & RTF_UP) || dst->sin6_family != AF_INET6 ||
501 	     !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_dst))) {
502 		RTFREE(ro->ro_rt);
503 		ro->ro_rt = NULL;
504 	}
505 	if (ro->ro_rt == NULL) {
506 		bzero(dst, sizeof(*dst));
507 		dst->sin6_family = AF_INET6;
508 		dst->sin6_len = sizeof(struct sockaddr_in6);
509 		dst->sin6_addr = ip6->ip6_dst;
510 	}
511 #if defined(IPSEC) || defined(FAST_IPSEC)
512 	if (needipsec && needipsectun) {
513 		struct ipsec_output_state state;
514 
515 		/*
516 		 * All the extension headers will become inaccessible
517 		 * (since they can be encrypted).
518 		 * Don't panic, we need no more updates to extension headers
519 		 * on inner IPv6 packet (since they are now encapsulated).
520 		 *
521 		 * IPv6 [ESP|AH] IPv6 [extension headers] payload
522 		 */
523 		bzero(&exthdrs, sizeof(exthdrs));
524 		exthdrs.ip6e_ip6 = m;
525 
526 		bzero(&state, sizeof(state));
527 		state.m = m;
528 		state.ro = (struct route *)ro;
529 		state.dst = (struct sockaddr *)dst;
530 
531 		error = ipsec6_output_tunnel(&state, sp, flags);
532 
533 		m = state.m;
534 		ro = (struct route_in6 *)state.ro;
535 		dst = (struct sockaddr_in6 *)state.dst;
536 		if (error) {
537 			/* mbuf is already reclaimed in ipsec6_output_tunnel. */
538 			m0 = m = NULL;
539 			m = NULL;
540 			switch (error) {
541 			case EHOSTUNREACH:
542 			case ENETUNREACH:
543 			case EMSGSIZE:
544 			case ENOBUFS:
545 			case ENOMEM:
546 				break;
547 			default:
548 				kprintf("ip6_output (ipsec): error code %d\n", error);
549 				/* fall through */
550 			case ENOENT:
551 				/* don't show these error codes to the user */
552 				error = 0;
553 				break;
554 			}
555 			goto bad;
556 		}
557 
558 		exthdrs.ip6e_ip6 = m;
559 	}
560 #endif
561 
562 	if (!IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
563 		/* Unicast */
564 
565 #define ifatoia6(ifa)	((struct in6_ifaddr *)(ifa))
566 #define sin6tosa(sin6)	((struct sockaddr *)(sin6))
567 		/* xxx
568 		 * interface selection comes here
569 		 * if an interface is specified from an upper layer,
570 		 * ifp must point it.
571 		 */
572 		if (ro->ro_rt == NULL) {
573 			/*
574 			 * non-bsdi always clone routes, if parent is
575 			 * PRF_CLONING.
576 			 */
577 			rtalloc((struct route *)ro);
578 		}
579 		if (ro->ro_rt == NULL) {
580 			ip6stat.ip6s_noroute++;
581 			error = EHOSTUNREACH;
582 			/* XXX in6_ifstat_inc(ifp, ifs6_out_discard); */
583 			goto bad;
584 		}
585 		ia = ifatoia6(ro->ro_rt->rt_ifa);
586 		ifp = ro->ro_rt->rt_ifp;
587 		ro->ro_rt->rt_use++;
588 		if (ro->ro_rt->rt_flags & RTF_GATEWAY)
589 			dst = (struct sockaddr_in6 *)ro->ro_rt->rt_gateway;
590 		m->m_flags &= ~(M_BCAST | M_MCAST);	/* just in case */
591 
592 		in6_ifstat_inc(ifp, ifs6_out_request);
593 
594 		/*
595 		 * Check if the outgoing interface conflicts with
596 		 * the interface specified by ifi6_ifindex (if specified).
597 		 * Note that loopback interface is always okay.
598 		 * (this may happen when we are sending a packet to one of
599 		 *  our own addresses.)
600 		 */
601 		if (opt && opt->ip6po_pktinfo
602 		 && opt->ip6po_pktinfo->ipi6_ifindex) {
603 			if (!(ifp->if_flags & IFF_LOOPBACK)
604 			 && ifp->if_index != opt->ip6po_pktinfo->ipi6_ifindex) {
605 				ip6stat.ip6s_noroute++;
606 				in6_ifstat_inc(ifp, ifs6_out_discard);
607 				error = EHOSTUNREACH;
608 				goto bad;
609 			}
610 		}
611 
612 		if (opt && opt->ip6po_hlim != -1)
613 			ip6->ip6_hlim = opt->ip6po_hlim & 0xff;
614 	} else {
615 		/* Multicast */
616 		struct	in6_multi *in6m;
617 
618 		m->m_flags = (m->m_flags & ~M_BCAST) | M_MCAST;
619 
620 		/*
621 		 * See if the caller provided any multicast options
622 		 */
623 		ifp = NULL;
624 		if (im6o != NULL) {
625 			ip6->ip6_hlim = im6o->im6o_multicast_hlim;
626 			if (im6o->im6o_multicast_ifp != NULL)
627 				ifp = im6o->im6o_multicast_ifp;
628 		} else
629 			ip6->ip6_hlim = ip6_defmcasthlim;
630 
631 		/*
632 		 * See if the caller provided the outgoing interface
633 		 * as an ancillary data.
634 		 * Boundary check for ifindex is assumed to be already done.
635 		 */
636 		if (opt && opt->ip6po_pktinfo && opt->ip6po_pktinfo->ipi6_ifindex)
637 			ifp = ifindex2ifnet[opt->ip6po_pktinfo->ipi6_ifindex];
638 
639 		/*
640 		 * If the destination is a node-local scope multicast,
641 		 * the packet should be loop-backed only.
642 		 */
643 		if (IN6_IS_ADDR_MC_NODELOCAL(&ip6->ip6_dst)) {
644 			/*
645 			 * If the outgoing interface is already specified,
646 			 * it should be a loopback interface.
647 			 */
648 			if (ifp && !(ifp->if_flags & IFF_LOOPBACK)) {
649 				ip6stat.ip6s_badscope++;
650 				error = ENETUNREACH; /* XXX: better error? */
651 				/* XXX correct ifp? */
652 				in6_ifstat_inc(ifp, ifs6_out_discard);
653 				goto bad;
654 			} else {
655 				ifp = &loif[0];
656 			}
657 		}
658 
659 		if (opt && opt->ip6po_hlim != -1)
660 			ip6->ip6_hlim = opt->ip6po_hlim & 0xff;
661 
662 		/*
663 		 * If caller did not provide an interface lookup a
664 		 * default in the routing table.  This is either a
665 		 * default for the speicfied group (i.e. a host
666 		 * route), or a multicast default (a route for the
667 		 * ``net'' ff00::/8).
668 		 */
669 		if (ifp == NULL) {
670 			if (ro->ro_rt == NULL) {
671 				ro->ro_rt =
672 				  rtpurelookup((struct sockaddr *)&ro->ro_dst);
673 			}
674 			if (ro->ro_rt == NULL) {
675 				ip6stat.ip6s_noroute++;
676 				error = EHOSTUNREACH;
677 				/* XXX in6_ifstat_inc(ifp, ifs6_out_discard) */
678 				goto bad;
679 			}
680 			ia = ifatoia6(ro->ro_rt->rt_ifa);
681 			ifp = ro->ro_rt->rt_ifp;
682 			ro->ro_rt->rt_use++;
683 		}
684 
685 		if (!(flags & IPV6_FORWARDING))
686 			in6_ifstat_inc(ifp, ifs6_out_request);
687 		in6_ifstat_inc(ifp, ifs6_out_mcast);
688 
689 		/*
690 		 * Confirm that the outgoing interface supports multicast.
691 		 */
692 		if (!(ifp->if_flags & IFF_MULTICAST)) {
693 			ip6stat.ip6s_noroute++;
694 			in6_ifstat_inc(ifp, ifs6_out_discard);
695 			error = ENETUNREACH;
696 			goto bad;
697 		}
698 		IN6_LOOKUP_MULTI(ip6->ip6_dst, ifp, in6m);
699 		if (in6m != NULL &&
700 		   (im6o == NULL || im6o->im6o_multicast_loop)) {
701 			/*
702 			 * If we belong to the destination multicast group
703 			 * on the outgoing interface, and the caller did not
704 			 * forbid loopback, loop back a copy.
705 			 */
706 			ip6_mloopback(ifp, m, dst);
707 		} else {
708 			/*
709 			 * If we are acting as a multicast router, perform
710 			 * multicast forwarding as if the packet had just
711 			 * arrived on the interface to which we are about
712 			 * to send.  The multicast forwarding function
713 			 * recursively calls this function, using the
714 			 * IPV6_FORWARDING flag to prevent infinite recursion.
715 			 *
716 			 * Multicasts that are looped back by ip6_mloopback(),
717 			 * above, will be forwarded by the ip6_input() routine,
718 			 * if necessary.
719 			 */
720 			if (ip6_mrouter && !(flags & IPV6_FORWARDING)) {
721 				if (ip6_mforward(ip6, ifp, m) != 0) {
722 					m_freem(m);
723 					goto done;
724 				}
725 			}
726 		}
727 		/*
728 		 * Multicasts with a hoplimit of zero may be looped back,
729 		 * above, but must not be transmitted on a network.
730 		 * Also, multicasts addressed to the loopback interface
731 		 * are not sent -- the above call to ip6_mloopback() will
732 		 * loop back a copy if this host actually belongs to the
733 		 * destination group on the loopback interface.
734 		 */
735 		if (ip6->ip6_hlim == 0 || (ifp->if_flags & IFF_LOOPBACK)) {
736 			m_freem(m);
737 			goto done;
738 		}
739 	}
740 
741 	/*
742 	 * Fill the outgoing inteface to tell the upper layer
743 	 * to increment per-interface statistics.
744 	 */
745 	if (ifpp)
746 		*ifpp = ifp;
747 
748 	/*
749 	 * Determine path MTU.
750 	 */
751 	if (ro_pmtu != ro) {
752 		/* The first hop and the final destination may differ. */
753 		struct sockaddr_in6 *sin6_fin =
754 			(struct sockaddr_in6 *)&ro_pmtu->ro_dst;
755 
756 		if (ro_pmtu->ro_rt != NULL &&
757 		    (!(ro->ro_rt->rt_flags & RTF_UP) ||
758 		     !IN6_ARE_ADDR_EQUAL(&sin6_fin->sin6_addr, &finaldst))) {
759 			RTFREE(ro_pmtu->ro_rt);
760 			ro_pmtu->ro_rt = NULL;
761 		}
762 		if (ro_pmtu->ro_rt == NULL) {
763 			bzero(sin6_fin, sizeof(*sin6_fin));
764 			sin6_fin->sin6_family = AF_INET6;
765 			sin6_fin->sin6_len = sizeof(struct sockaddr_in6);
766 			sin6_fin->sin6_addr = finaldst;
767 
768 			rtalloc((struct route *)ro_pmtu);
769 		}
770 	}
771 	if (ro_pmtu->ro_rt != NULL) {
772 		u_int32_t ifmtu = ND_IFINFO(ifp)->linkmtu;
773 
774 		mtu = ro_pmtu->ro_rt->rt_rmx.rmx_mtu;
775 		if (mtu > ifmtu || mtu == 0) {
776 			/*
777 			 * The MTU on the route is larger than the MTU on
778 			 * the interface!  This shouldn't happen, unless the
779 			 * MTU of the interface has been changed after the
780 			 * interface was brought up.  Change the MTU in the
781 			 * route to match the interface MTU (as long as the
782 			 * field isn't locked).
783 			 *
784 			 * if MTU on the route is 0, we need to fix the MTU.
785 			 * this case happens with path MTU discovery timeouts.
786 			 */
787 			 mtu = ifmtu;
788 			 if (!(ro_pmtu->ro_rt->rt_rmx.rmx_locks & RTV_MTU))
789 				 ro_pmtu->ro_rt->rt_rmx.rmx_mtu = mtu; /* XXX */
790 		}
791 	} else {
792 		mtu = ND_IFINFO(ifp)->linkmtu;
793 	}
794 
795 	/*
796 	 * advanced API (IPV6_USE_MIN_MTU) overrides mtu setting
797 	 */
798 	if ((flags & IPV6_MINMTU) != 0 && mtu > IPV6_MMTU)
799 		mtu = IPV6_MMTU;
800 
801 	/* Fake scoped addresses */
802 	if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
803 		/*
804 		 * If source or destination address is a scoped address, and
805 		 * the packet is going to be sent to a loopback interface,
806 		 * we should keep the original interface.
807 		 */
808 
809 		/*
810 		 * XXX: this is a very experimental and temporary solution.
811 		 * We eventually have sockaddr_in6 and use the sin6_scope_id
812 		 * field of the structure here.
813 		 * We rely on the consistency between two scope zone ids
814 		 * of source and destination, which should already be assured.
815 		 * Larger scopes than link will be supported in the future.
816 		 */
817 		origifp = NULL;
818 		if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src))
819 			origifp = ifindex2ifnet[ntohs(ip6->ip6_src.s6_addr16[1])];
820 		else if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst))
821 			origifp = ifindex2ifnet[ntohs(ip6->ip6_dst.s6_addr16[1])];
822 		/*
823 		 * XXX: origifp can be NULL even in those two cases above.
824 		 * For example, if we remove the (only) link-local address
825 		 * from the loopback interface, and try to send a link-local
826 		 * address without link-id information.  Then the source
827 		 * address is ::1, and the destination address is the
828 		 * link-local address with its s6_addr16[1] being zero.
829 		 * What is worse, if the packet goes to the loopback interface
830 		 * by a default rejected route, the null pointer would be
831 		 * passed to looutput, and the kernel would hang.
832 		 * The following last resort would prevent such disaster.
833 		 */
834 		if (origifp == NULL)
835 			origifp = ifp;
836 	}
837 	else
838 		origifp = ifp;
839 	/*
840 	 * clear embedded scope identifiers if necessary.
841 	 * in6_clearscope will touch the addresses only when necessary.
842 	 */
843 	in6_clearscope(&ip6->ip6_src);
844 	in6_clearscope(&ip6->ip6_dst);
845 
846 	/*
847 	 * Check with the firewall...
848 	 */
849 	if (ip6_fw_enable && ip6_fw_chk_ptr) {
850 		u_short port = 0;
851 
852 		m->m_pkthdr.rcvif = NULL;	/* XXX */
853 		/* If ipfw says divert, we have to just drop packet */
854 		if ((*ip6_fw_chk_ptr)(&ip6, ifp, &port, &m)) {
855 			m_freem(m);
856 			goto done;
857 		}
858 		if (!m) {
859 			error = EACCES;
860 			goto done;
861 		}
862 	}
863 
864 	/*
865 	 * If the outgoing packet contains a hop-by-hop options header,
866 	 * it must be examined and processed even by the source node.
867 	 * (RFC 2460, section 4.)
868 	 */
869 	if (exthdrs.ip6e_hbh) {
870 		struct ip6_hbh *hbh = mtod(exthdrs.ip6e_hbh, struct ip6_hbh *);
871 		u_int32_t dummy1; /* XXX unused */
872 		u_int32_t dummy2; /* XXX unused */
873 
874 #ifdef DIAGNOSTIC
875 		if ((hbh->ip6h_len + 1) << 3 > exthdrs.ip6e_hbh->m_len)
876 			panic("ip6e_hbh is not continuous");
877 #endif
878 		/*
879 		 *  XXX: if we have to send an ICMPv6 error to the sender,
880 		 *       we need the M_LOOP flag since icmp6_error() expects
881 		 *       the IPv6 and the hop-by-hop options header are
882 		 *       continuous unless the flag is set.
883 		 */
884 		m->m_flags |= M_LOOP;
885 		m->m_pkthdr.rcvif = ifp;
886 		if (ip6_process_hopopts(m,
887 					(u_int8_t *)(hbh + 1),
888 					((hbh->ip6h_len + 1) << 3) -
889 					sizeof(struct ip6_hbh),
890 					&dummy1, &dummy2) < 0) {
891 			/* m was already freed at this point */
892 			error = EINVAL;/* better error? */
893 			goto done;
894 		}
895 		m->m_flags &= ~M_LOOP; /* XXX */
896 		m->m_pkthdr.rcvif = NULL;
897 	}
898 
899 	/*
900 	 * Run through list of hooks for output packets.
901 	 */
902 	if (pfil_has_hooks(&inet6_pfil_hook)) {
903 		error = pfil_run_hooks(&inet6_pfil_hook, &m, ifp, PFIL_OUT);
904 		if (error != 0 || m == NULL)
905 			goto done;
906 		ip6 = mtod(m, struct ip6_hdr *);
907 	}
908 
909 	/*
910 	 * Send the packet to the outgoing interface.
911 	 * If necessary, do IPv6 fragmentation before sending.
912 	 */
913 	tlen = m->m_pkthdr.len;
914 	if (tlen <= mtu
915 #ifdef notyet
916 	    /*
917 	     * On any link that cannot convey a 1280-octet packet in one piece,
918 	     * link-specific fragmentation and reassembly must be provided at
919 	     * a layer below IPv6. [RFC 2460, sec.5]
920 	     * Thus if the interface has ability of link-level fragmentation,
921 	     * we can just send the packet even if the packet size is
922 	     * larger than the link's MTU.
923 	     * XXX: IFF_FRAGMENTABLE (or such) flag has not been defined yet...
924 	     */
925 
926 	    || ifp->if_flags & IFF_FRAGMENTABLE
927 #endif
928 	    )
929 	{
930  		/* Record statistics for this interface address. */
931  		if (ia && !(flags & IPV6_FORWARDING)) {
932  			ia->ia_ifa.if_opackets++;
933  			ia->ia_ifa.if_obytes += m->m_pkthdr.len;
934  		}
935 #ifdef IPSEC
936 		/* clean ipsec history once it goes out of the node */
937 		ipsec_delaux(m);
938 #endif
939 		error = nd6_output(ifp, origifp, m, dst, ro->ro_rt);
940 		goto done;
941 	} else if (mtu < IPV6_MMTU) {
942 		/*
943 		 * note that path MTU is never less than IPV6_MMTU
944 		 * (see icmp6_input).
945 		 */
946 		error = EMSGSIZE;
947 		in6_ifstat_inc(ifp, ifs6_out_fragfail);
948 		goto bad;
949 	} else if (ip6->ip6_plen == 0) { /* jumbo payload cannot be fragmented */
950 		error = EMSGSIZE;
951 		in6_ifstat_inc(ifp, ifs6_out_fragfail);
952 		goto bad;
953 	} else {
954 		struct mbuf **mnext, *m_frgpart;
955 		struct ip6_frag *ip6f;
956 		u_int32_t id = htonl(ip6_id++);
957 		u_char nextproto;
958 
959 		/*
960 		 * Too large for the destination or interface;
961 		 * fragment if possible.
962 		 * Must be able to put at least 8 bytes per fragment.
963 		 */
964 		hlen = unfragpartlen;
965 		if (mtu > IPV6_MAXPACKET)
966 			mtu = IPV6_MAXPACKET;
967 
968 		len = (mtu - hlen - sizeof(struct ip6_frag)) & ~7;
969 		if (len < 8) {
970 			error = EMSGSIZE;
971 			in6_ifstat_inc(ifp, ifs6_out_fragfail);
972 			goto bad;
973 		}
974 
975 		mnext = &m->m_nextpkt;
976 
977 		/*
978 		 * Change the next header field of the last header in the
979 		 * unfragmentable part.
980 		 */
981 		if (exthdrs.ip6e_rthdr) {
982 			nextproto = *mtod(exthdrs.ip6e_rthdr, u_char *);
983 			*mtod(exthdrs.ip6e_rthdr, u_char *) = IPPROTO_FRAGMENT;
984 		} else if (exthdrs.ip6e_dest1) {
985 			nextproto = *mtod(exthdrs.ip6e_dest1, u_char *);
986 			*mtod(exthdrs.ip6e_dest1, u_char *) = IPPROTO_FRAGMENT;
987 		} else if (exthdrs.ip6e_hbh) {
988 			nextproto = *mtod(exthdrs.ip6e_hbh, u_char *);
989 			*mtod(exthdrs.ip6e_hbh, u_char *) = IPPROTO_FRAGMENT;
990 		} else {
991 			nextproto = ip6->ip6_nxt;
992 			ip6->ip6_nxt = IPPROTO_FRAGMENT;
993 		}
994 
995 		/*
996 		 * Loop through length of segment after first fragment,
997 		 * make new header and copy data of each part and link onto
998 		 * chain.
999 		 */
1000 		m0 = m;
1001 		for (off = hlen; off < tlen; off += len) {
1002 			MGETHDR(m, MB_DONTWAIT, MT_HEADER);
1003 			if (!m) {
1004 				error = ENOBUFS;
1005 				ip6stat.ip6s_odropped++;
1006 				goto sendorfree;
1007 			}
1008 			m->m_pkthdr.rcvif = NULL;
1009 			m->m_flags = m0->m_flags & M_COPYFLAGS;
1010 			*mnext = m;
1011 			mnext = &m->m_nextpkt;
1012 			m->m_data += max_linkhdr;
1013 			mhip6 = mtod(m, struct ip6_hdr *);
1014 			*mhip6 = *ip6;
1015 			m->m_len = sizeof(*mhip6);
1016  			error = ip6_insertfraghdr(m0, m, hlen, &ip6f);
1017  			if (error) {
1018 				ip6stat.ip6s_odropped++;
1019 				goto sendorfree;
1020 			}
1021 			ip6f->ip6f_offlg = htons((u_short)((off - hlen) & ~7));
1022 			if (off + len >= tlen)
1023 				len = tlen - off;
1024 			else
1025 				ip6f->ip6f_offlg |= IP6F_MORE_FRAG;
1026 			mhip6->ip6_plen = htons((u_short)(len + hlen +
1027 							  sizeof(*ip6f) -
1028 							  sizeof(struct ip6_hdr)));
1029 			if ((m_frgpart = m_copy(m0, off, len)) == NULL) {
1030 				error = ENOBUFS;
1031 				ip6stat.ip6s_odropped++;
1032 				goto sendorfree;
1033 			}
1034 			m_cat(m, m_frgpart);
1035 			m->m_pkthdr.len = len + hlen + sizeof(*ip6f);
1036 			m->m_pkthdr.rcvif = (struct ifnet *)0;
1037 			ip6f->ip6f_reserved = 0;
1038 			ip6f->ip6f_ident = id;
1039 			ip6f->ip6f_nxt = nextproto;
1040 			ip6stat.ip6s_ofragments++;
1041 			in6_ifstat_inc(ifp, ifs6_out_fragcreat);
1042 		}
1043 
1044 		in6_ifstat_inc(ifp, ifs6_out_fragok);
1045 	}
1046 
1047 	/*
1048 	 * Remove leading garbages.
1049 	 */
1050 sendorfree:
1051 	m = m0->m_nextpkt;
1052 	m0->m_nextpkt = NULL;
1053 	m_freem(m0);
1054 	for (m0 = m; m; m = m0) {
1055 		m0 = m->m_nextpkt;
1056 		m->m_nextpkt = NULL;
1057 		if (error == 0) {
1058  			/* Record statistics for this interface address. */
1059  			if (ia) {
1060  				ia->ia_ifa.if_opackets++;
1061  				ia->ia_ifa.if_obytes += m->m_pkthdr.len;
1062  			}
1063 #ifdef IPSEC
1064 			/* clean ipsec history once it goes out of the node */
1065 			ipsec_delaux(m);
1066 #endif
1067 			error = nd6_output(ifp, origifp, m, dst, ro->ro_rt);
1068 		} else
1069 			m_freem(m);
1070 	}
1071 
1072 	if (error == 0)
1073 		ip6stat.ip6s_fragmented++;
1074 
1075 done:
1076 	if (ro == &ip6route && ro->ro_rt) { /* brace necessary for RTFREE */
1077 		RTFREE(ro->ro_rt);
1078 	} else if (ro_pmtu == &ip6route && ro_pmtu->ro_rt) {
1079 		RTFREE(ro_pmtu->ro_rt);
1080 	}
1081 
1082 #ifdef IPSEC
1083 	if (sp != NULL)
1084 		key_freesp(sp);
1085 #endif
1086 #ifdef FAST_IPSEC
1087 	if (sp != NULL)
1088 		KEY_FREESP(&sp);
1089 #endif
1090 
1091 	return (error);
1092 
1093 freehdrs:
1094 	m_freem(exthdrs.ip6e_hbh);	/* m_freem will check if mbuf is 0 */
1095 	m_freem(exthdrs.ip6e_dest1);
1096 	m_freem(exthdrs.ip6e_rthdr);
1097 	m_freem(exthdrs.ip6e_dest2);
1098 	/* fall through */
1099 bad:
1100 	m_freem(m);
1101 	goto done;
1102 }
1103 
1104 static int
1105 copyexthdr(void *h, struct mbuf **mp)
1106 {
1107 	struct ip6_ext *hdr = h;
1108 	int hlen;
1109 	struct mbuf *m;
1110 
1111 	if (hdr == NULL)
1112 		return 0;
1113 
1114 	hlen = (hdr->ip6e_len + 1) * 8;
1115 	if (hlen > MCLBYTES)
1116 		return ENOBUFS;	/* XXX */
1117 
1118 	m = m_getb(hlen, MB_DONTWAIT, MT_DATA, 0);
1119 	if (!m)
1120 		return ENOBUFS;
1121 	m->m_len = hlen;
1122 
1123 	bcopy(hdr, mtod(m, caddr_t), hlen);
1124 
1125 	*mp = m;
1126 	return 0;
1127 }
1128 
1129 /*
1130  * Insert jumbo payload option.
1131  */
1132 static int
1133 ip6_insert_jumboopt(struct ip6_exthdrs *exthdrs, u_int32_t plen)
1134 {
1135 	struct mbuf *mopt;
1136 	u_char *optbuf;
1137 	u_int32_t v;
1138 
1139 #define JUMBOOPTLEN	8	/* length of jumbo payload option and padding */
1140 
1141 	/*
1142 	 * If there is no hop-by-hop options header, allocate new one.
1143 	 * If there is one but it doesn't have enough space to store the
1144 	 * jumbo payload option, allocate a cluster to store the whole options.
1145 	 * Otherwise, use it to store the options.
1146 	 */
1147 	if (exthdrs->ip6e_hbh == NULL) {
1148 		MGET(mopt, MB_DONTWAIT, MT_DATA);
1149 		if (mopt == NULL)
1150 			return (ENOBUFS);
1151 		mopt->m_len = JUMBOOPTLEN;
1152 		optbuf = mtod(mopt, u_char *);
1153 		optbuf[1] = 0;	/* = ((JUMBOOPTLEN) >> 3) - 1 */
1154 		exthdrs->ip6e_hbh = mopt;
1155 	} else {
1156 		struct ip6_hbh *hbh;
1157 
1158 		mopt = exthdrs->ip6e_hbh;
1159 		if (M_TRAILINGSPACE(mopt) < JUMBOOPTLEN) {
1160 			/*
1161 			 * XXX assumption:
1162 			 * - exthdrs->ip6e_hbh is not referenced from places
1163 			 *   other than exthdrs.
1164 			 * - exthdrs->ip6e_hbh is not an mbuf chain.
1165 			 */
1166 			int oldoptlen = mopt->m_len;
1167 			struct mbuf *n;
1168 
1169 			/*
1170 			 * XXX: give up if the whole (new) hbh header does
1171 			 * not fit even in an mbuf cluster.
1172 			 */
1173 			if (oldoptlen + JUMBOOPTLEN > MCLBYTES)
1174 				return (ENOBUFS);
1175 
1176 			/*
1177 			 * As a consequence, we must always prepare a cluster
1178 			 * at this point.
1179 			 */
1180 			n = m_getcl(MB_DONTWAIT, MT_DATA, 0);
1181 			if (!n)
1182 				return (ENOBUFS);
1183 			n->m_len = oldoptlen + JUMBOOPTLEN;
1184 			bcopy(mtod(mopt, caddr_t), mtod(n, caddr_t), oldoptlen);
1185 			optbuf = mtod(n, caddr_t) + oldoptlen;
1186 			m_freem(mopt);
1187 			mopt = exthdrs->ip6e_hbh = n;
1188 		} else {
1189 			optbuf = mtod(mopt, u_char *) + mopt->m_len;
1190 			mopt->m_len += JUMBOOPTLEN;
1191 		}
1192 		optbuf[0] = IP6OPT_PADN;
1193 		optbuf[1] = 1;
1194 
1195 		/*
1196 		 * Adjust the header length according to the pad and
1197 		 * the jumbo payload option.
1198 		 */
1199 		hbh = mtod(mopt, struct ip6_hbh *);
1200 		hbh->ip6h_len += (JUMBOOPTLEN >> 3);
1201 	}
1202 
1203 	/* fill in the option. */
1204 	optbuf[2] = IP6OPT_JUMBO;
1205 	optbuf[3] = 4;
1206 	v = (u_int32_t)htonl(plen + JUMBOOPTLEN);
1207 	bcopy(&v, &optbuf[4], sizeof(u_int32_t));
1208 
1209 	/* finally, adjust the packet header length */
1210 	exthdrs->ip6e_ip6->m_pkthdr.len += JUMBOOPTLEN;
1211 
1212 	return (0);
1213 #undef JUMBOOPTLEN
1214 }
1215 
1216 /*
1217  * Insert fragment header and copy unfragmentable header portions.
1218  */
1219 static int
1220 ip6_insertfraghdr(struct mbuf *m0, struct mbuf *m, int hlen,
1221 		  struct ip6_frag **frghdrp)
1222 {
1223 	struct mbuf *n, *mlast;
1224 
1225 	if (hlen > sizeof(struct ip6_hdr)) {
1226 		n = m_copym(m0, sizeof(struct ip6_hdr),
1227 			    hlen - sizeof(struct ip6_hdr), MB_DONTWAIT);
1228 		if (n == NULL)
1229 			return (ENOBUFS);
1230 		m->m_next = n;
1231 	} else
1232 		n = m;
1233 
1234 	/* Search for the last mbuf of unfragmentable part. */
1235 	for (mlast = n; mlast->m_next; mlast = mlast->m_next)
1236 		;
1237 
1238 	if (!(mlast->m_flags & M_EXT) &&
1239 	    M_TRAILINGSPACE(mlast) >= sizeof(struct ip6_frag)) {
1240 		/* use the trailing space of the last mbuf for the fragment hdr */
1241 		*frghdrp =
1242 			(struct ip6_frag *)(mtod(mlast, caddr_t) + mlast->m_len);
1243 		mlast->m_len += sizeof(struct ip6_frag);
1244 		m->m_pkthdr.len += sizeof(struct ip6_frag);
1245 	} else {
1246 		/* allocate a new mbuf for the fragment header */
1247 		struct mbuf *mfrg;
1248 
1249 		MGET(mfrg, MB_DONTWAIT, MT_DATA);
1250 		if (mfrg == NULL)
1251 			return (ENOBUFS);
1252 		mfrg->m_len = sizeof(struct ip6_frag);
1253 		*frghdrp = mtod(mfrg, struct ip6_frag *);
1254 		mlast->m_next = mfrg;
1255 	}
1256 
1257 	return (0);
1258 }
1259 
1260 /*
1261  * IP6 socket option processing.
1262  */
1263 int
1264 ip6_ctloutput(struct socket *so, struct sockopt *sopt)
1265 {
1266 	int privileged;
1267 	struct inpcb *in6p = so->so_pcb;
1268 	int error, optval;
1269 	int level, op, optname;
1270 	int optlen;
1271 	struct thread *td;
1272 
1273 	if (sopt) {
1274 		level = sopt->sopt_level;
1275 		op = sopt->sopt_dir;
1276 		optname = sopt->sopt_name;
1277 		optlen = sopt->sopt_valsize;
1278 		td = sopt->sopt_td;
1279 	} else {
1280 		panic("ip6_ctloutput: arg soopt is NULL");
1281 		/* NOT REACHED */
1282 		td = NULL;
1283 	}
1284 	error = optval = 0;
1285 
1286 	privileged = (td == NULL || suser(td)) ? 0 : 1;
1287 
1288 	if (level == IPPROTO_IPV6) {
1289 		switch (op) {
1290 
1291 		case SOPT_SET:
1292 			switch (optname) {
1293 			case IPV6_PKTOPTIONS:
1294 			{
1295 				struct mbuf *m;
1296 
1297 				error = soopt_getm(sopt, &m); /* XXX */
1298 				if (error != 0)
1299 					break;
1300 				soopt_to_mbuf(sopt, m); /* XXX */
1301 				error = ip6_pcbopts(&in6p->in6p_outputopts,
1302 						    m, so, sopt);
1303 				m_freem(m); /* XXX */
1304 				break;
1305 			}
1306 
1307 			/*
1308 			 * Use of some Hop-by-Hop options or some
1309 			 * Destination options, might require special
1310 			 * privilege.  That is, normal applications
1311 			 * (without special privilege) might be forbidden
1312 			 * from setting certain options in outgoing packets,
1313 			 * and might never see certain options in received
1314 			 * packets. [RFC 2292 Section 6]
1315 			 * KAME specific note:
1316 			 *  KAME prevents non-privileged users from sending or
1317 			 *  receiving ANY hbh/dst options in order to avoid
1318 			 *  overhead of parsing options in the kernel.
1319 			 */
1320 			case IPV6_UNICAST_HOPS:
1321 			case IPV6_CHECKSUM:
1322 			case IPV6_FAITH:
1323 
1324 			case IPV6_V6ONLY:
1325 				if (optlen != sizeof(int)) {
1326 					error = EINVAL;
1327 					break;
1328 				}
1329 				error = soopt_to_kbuf(sopt, &optval,
1330 					sizeof optval, sizeof optval);
1331 				if (error)
1332 					break;
1333 				switch (optname) {
1334 
1335 				case IPV6_UNICAST_HOPS:
1336 					if (optval < -1 || optval >= 256)
1337 						error = EINVAL;
1338 					else {
1339 						/* -1 = kernel default */
1340 						in6p->in6p_hops = optval;
1341 
1342 						if ((in6p->in6p_vflag &
1343 						     INP_IPV4) != 0)
1344 							in6p->inp_ip_ttl = optval;
1345 					}
1346 					break;
1347 #define OPTSET(bit) \
1348 do { \
1349 	if (optval) \
1350 		in6p->in6p_flags |= (bit); \
1351 	else \
1352 		in6p->in6p_flags &= ~(bit); \
1353 } while (0)
1354 #define OPTBIT(bit) (in6p->in6p_flags & (bit) ? 1 : 0)
1355 
1356 				case IPV6_CHECKSUM:
1357 					in6p->in6p_cksum = optval;
1358 					break;
1359 
1360 				case IPV6_FAITH:
1361 					OPTSET(IN6P_FAITH);
1362 					break;
1363 
1364 				case IPV6_V6ONLY:
1365 					/*
1366 					 * make setsockopt(IPV6_V6ONLY)
1367 					 * available only prior to bind(2).
1368 					 * see ipng mailing list, Jun 22 2001.
1369 					 */
1370 					if (in6p->in6p_lport ||
1371 					    !IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_laddr))
1372 					{
1373 						error = EINVAL;
1374 						break;
1375 					}
1376 					OPTSET(IN6P_IPV6_V6ONLY);
1377 					if (optval)
1378 						in6p->in6p_vflag &= ~INP_IPV4;
1379 					else
1380 						in6p->in6p_vflag |= INP_IPV4;
1381 					break;
1382 				}
1383 				break;
1384 
1385 			case IPV6_PKTINFO:
1386 			case IPV6_HOPLIMIT:
1387 			case IPV6_HOPOPTS:
1388 			case IPV6_DSTOPTS:
1389 			case IPV6_RTHDR:
1390 				/* RFC 2292 */
1391 				if (optlen != sizeof(int)) {
1392 					error = EINVAL;
1393 					break;
1394 				}
1395 				error = soopt_to_kbuf(sopt, &optval,
1396 					sizeof optval, sizeof optval);
1397 				if (error)
1398 					break;
1399 				switch (optname) {
1400 				case IPV6_PKTINFO:
1401 					OPTSET(IN6P_PKTINFO);
1402 					break;
1403 				case IPV6_HOPLIMIT:
1404 					OPTSET(IN6P_HOPLIMIT);
1405 					break;
1406 				case IPV6_HOPOPTS:
1407 					/*
1408 					 * Check super-user privilege.
1409 					 * See comments for IPV6_RECVHOPOPTS.
1410 					 */
1411 					if (!privileged)
1412 						return (EPERM);
1413 					OPTSET(IN6P_HOPOPTS);
1414 					break;
1415 				case IPV6_DSTOPTS:
1416 					if (!privileged)
1417 						return (EPERM);
1418 					OPTSET(IN6P_DSTOPTS|IN6P_RTHDRDSTOPTS); /* XXX */
1419 					break;
1420 				case IPV6_RTHDR:
1421 					OPTSET(IN6P_RTHDR);
1422 					break;
1423 				}
1424 				break;
1425 #undef OPTSET
1426 
1427 			case IPV6_MULTICAST_IF:
1428 			case IPV6_MULTICAST_HOPS:
1429 			case IPV6_MULTICAST_LOOP:
1430 			case IPV6_JOIN_GROUP:
1431 			case IPV6_LEAVE_GROUP:
1432 			    {
1433 				struct mbuf *m;
1434 				if (sopt->sopt_valsize > MLEN) {
1435 					error = EMSGSIZE;
1436 					break;
1437 				}
1438 				/* XXX */
1439 				MGET(m, sopt->sopt_td ? MB_WAIT : MB_DONTWAIT, MT_HEADER);
1440 				if (m == NULL) {
1441 					error = ENOBUFS;
1442 					break;
1443 				}
1444 				m->m_len = sopt->sopt_valsize;
1445 				error = soopt_to_kbuf(sopt, mtod(m, char *),
1446 						    m->m_len, m->m_len);
1447 				error =	ip6_setmoptions(sopt->sopt_name,
1448 							&in6p->in6p_moptions,
1449 							m);
1450 				m_free(m);
1451 			    }
1452 				break;
1453 
1454 			case IPV6_PORTRANGE:
1455 				error = soopt_to_kbuf(sopt, &optval,
1456 				    sizeof optval, sizeof optval);
1457 				if (error)
1458 					break;
1459 
1460 				switch (optval) {
1461 				case IPV6_PORTRANGE_DEFAULT:
1462 					in6p->in6p_flags &= ~(IN6P_LOWPORT);
1463 					in6p->in6p_flags &= ~(IN6P_HIGHPORT);
1464 					break;
1465 
1466 				case IPV6_PORTRANGE_HIGH:
1467 					in6p->in6p_flags &= ~(IN6P_LOWPORT);
1468 					in6p->in6p_flags |= IN6P_HIGHPORT;
1469 					break;
1470 
1471 				case IPV6_PORTRANGE_LOW:
1472 					in6p->in6p_flags &= ~(IN6P_HIGHPORT);
1473 					in6p->in6p_flags |= IN6P_LOWPORT;
1474 					break;
1475 
1476 				default:
1477 					error = EINVAL;
1478 					break;
1479 				}
1480 				break;
1481 
1482 #if defined(IPSEC) || defined(FAST_IPSEC)
1483 			case IPV6_IPSEC_POLICY:
1484 			    {
1485 				caddr_t req = NULL;
1486 				size_t len = 0;
1487 				struct mbuf *m;
1488 
1489 				if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */
1490 					break;
1491 				soopt_to_mbuf(sopt, m);		/* XXX */
1492 				if (m) {
1493 					req = mtod(m, caddr_t);
1494 					len = m->m_len;
1495 				}
1496 				error = ipsec6_set_policy(in6p, optname, req,
1497 							  len, privileged);
1498 				m_freem(m);
1499 			    }
1500 				break;
1501 #endif /* KAME IPSEC */
1502 
1503 			case IPV6_FW_ADD:
1504 			case IPV6_FW_DEL:
1505 			case IPV6_FW_FLUSH:
1506 			case IPV6_FW_ZERO:
1507 			    {
1508 				struct mbuf *m;
1509 				struct mbuf **mp = &m;
1510 
1511 				if (ip6_fw_ctl_ptr == NULL)
1512 					return EINVAL;
1513 				/* XXX */
1514 				if ((error = soopt_getm(sopt, &m)) != 0)
1515 					break;
1516 				/* XXX */
1517 				soopt_to_mbuf(sopt, m);
1518 				error = (*ip6_fw_ctl_ptr)(optname, mp);
1519 				m = *mp;
1520 			    }
1521 				break;
1522 
1523 			default:
1524 				error = ENOPROTOOPT;
1525 				break;
1526 			}
1527 			break;
1528 
1529 		case SOPT_GET:
1530 			switch (optname) {
1531 
1532 			case IPV6_PKTOPTIONS:
1533 				if (in6p->in6p_options) {
1534 					struct mbuf *m;
1535 					m = m_copym(in6p->in6p_options,
1536 					    0, M_COPYALL, MB_WAIT);
1537 					error = soopt_from_mbuf(sopt, m);
1538 					if (error == 0)
1539 						m_freem(m);
1540 				} else
1541 					sopt->sopt_valsize = 0;
1542 				break;
1543 
1544 			case IPV6_UNICAST_HOPS:
1545 			case IPV6_CHECKSUM:
1546 
1547 			case IPV6_FAITH:
1548 			case IPV6_V6ONLY:
1549 			case IPV6_PORTRANGE:
1550 				switch (optname) {
1551 
1552 				case IPV6_UNICAST_HOPS:
1553 					optval = in6p->in6p_hops;
1554 					break;
1555 
1556 				case IPV6_CHECKSUM:
1557 					optval = in6p->in6p_cksum;
1558 					break;
1559 
1560 				case IPV6_FAITH:
1561 					optval = OPTBIT(IN6P_FAITH);
1562 					break;
1563 
1564 				case IPV6_V6ONLY:
1565 					optval = OPTBIT(IN6P_IPV6_V6ONLY);
1566 					break;
1567 
1568 				case IPV6_PORTRANGE:
1569 				    {
1570 					int flags;
1571 					flags = in6p->in6p_flags;
1572 					if (flags & IN6P_HIGHPORT)
1573 						optval = IPV6_PORTRANGE_HIGH;
1574 					else if (flags & IN6P_LOWPORT)
1575 						optval = IPV6_PORTRANGE_LOW;
1576 					else
1577 						optval = 0;
1578 					break;
1579 				    }
1580 				}
1581 				soopt_from_kbuf(sopt, &optval,
1582 					sizeof optval);
1583 				break;
1584 
1585 			case IPV6_PKTINFO:
1586 			case IPV6_HOPLIMIT:
1587 			case IPV6_HOPOPTS:
1588 			case IPV6_RTHDR:
1589 			case IPV6_DSTOPTS:
1590 				if (optname == IPV6_HOPOPTS ||
1591 				    optname == IPV6_DSTOPTS ||
1592 				    !privileged)
1593 					return (EPERM);
1594 				switch (optname) {
1595 				case IPV6_PKTINFO:
1596 					optval = OPTBIT(IN6P_PKTINFO);
1597 					break;
1598 				case IPV6_HOPLIMIT:
1599 					optval = OPTBIT(IN6P_HOPLIMIT);
1600 					break;
1601 				case IPV6_HOPOPTS:
1602 					if (!privileged)
1603 						return (EPERM);
1604 					optval = OPTBIT(IN6P_HOPOPTS);
1605 					break;
1606 				case IPV6_RTHDR:
1607 					optval = OPTBIT(IN6P_RTHDR);
1608 					break;
1609 				case IPV6_DSTOPTS:
1610 					if (!privileged)
1611 						return (EPERM);
1612 					optval = OPTBIT(IN6P_DSTOPTS|IN6P_RTHDRDSTOPTS);
1613 					break;
1614 				}
1615 				soopt_from_kbuf(sopt, &optval,
1616 					sizeof optval);
1617 				break;
1618 
1619 			case IPV6_MULTICAST_IF:
1620 			case IPV6_MULTICAST_HOPS:
1621 			case IPV6_MULTICAST_LOOP:
1622 			case IPV6_JOIN_GROUP:
1623 			case IPV6_LEAVE_GROUP:
1624 			    {
1625 				struct mbuf *m;
1626 				error = ip6_getmoptions(sopt->sopt_name,
1627 						in6p->in6p_moptions, &m);
1628 				if (error == 0)
1629 					soopt_from_kbuf(sopt,
1630 						mtod(m, char *), m->m_len);
1631 				m_freem(m);
1632 			    }
1633 				break;
1634 
1635 #if defined(IPSEC) || defined(FAST_IPSEC)
1636 			case IPV6_IPSEC_POLICY:
1637 			  {
1638 				caddr_t req = NULL;
1639 				size_t len = 0;
1640 				struct mbuf *m = NULL;
1641 				struct mbuf **mp = &m;
1642 
1643 				error = soopt_getm(sopt, &m); /* XXX */
1644 				if (error != 0)
1645 					break;
1646 				soopt_to_mbuf(sopt, m); /* XXX */
1647 				if (m) {
1648 					req = mtod(m, caddr_t);
1649 					len = m->m_len;
1650 				}
1651 				error = ipsec6_get_policy(in6p, req, len, mp);
1652 				if (error == 0)
1653 					error = soopt_from_mbuf(sopt, m); /*XXX*/
1654 				if (error == 0 && m != NULL)
1655 					m_freem(m);
1656 				break;
1657 			  }
1658 #endif /* KAME IPSEC */
1659 
1660 			case IPV6_FW_GET:
1661 			  {
1662 				struct mbuf *m;
1663 				struct mbuf **mp = &m;
1664 
1665 				if (ip6_fw_ctl_ptr == NULL)
1666 				{
1667 					return EINVAL;
1668 				}
1669 				error = (*ip6_fw_ctl_ptr)(optname, mp);
1670 				if (error == 0)
1671 					error = soopt_from_mbuf(sopt, m); /* XXX */
1672 				if (error == 0 && m != NULL)
1673 					m_freem(m);
1674 			  }
1675 				break;
1676 
1677 			default:
1678 				error = ENOPROTOOPT;
1679 				break;
1680 			}
1681 			break;
1682 		}
1683 	} else {
1684 		error = EINVAL;
1685 	}
1686 	return (error);
1687 }
1688 
1689 /*
1690  * Set up IP6 options in pcb for insertion in output packets or
1691  * specifying behavior of outgoing packets.
1692  */
1693 static int
1694 ip6_pcbopts(struct ip6_pktopts **pktopt, struct mbuf *m, struct socket *so,
1695 	    struct sockopt *sopt)
1696 {
1697 	struct ip6_pktopts *opt = *pktopt;
1698 	int error = 0;
1699 	struct thread *td = sopt->sopt_td;
1700 	int priv = 0;
1701 
1702 	/* turn off any old options. */
1703 	if (opt) {
1704 #ifdef DIAGNOSTIC
1705 		if (opt->ip6po_pktinfo || opt->ip6po_nexthop ||
1706 		    opt->ip6po_hbh || opt->ip6po_dest1 || opt->ip6po_dest2 ||
1707 		    opt->ip6po_rhinfo.ip6po_rhi_rthdr)
1708 			kprintf("ip6_pcbopts: all specified options are cleared.\n");
1709 #endif
1710 		ip6_clearpktopts(opt, 1, -1);
1711 	} else
1712 		opt = kmalloc(sizeof(*opt), M_IP6OPT, M_WAITOK);
1713 	*pktopt = NULL;
1714 
1715 	if (m == NULL || m->m_len == 0) {
1716 		/*
1717 		 * Only turning off any previous options, regardless of
1718 		 * whether the opt is just created or given.
1719 		 */
1720 		kfree(opt, M_IP6OPT);
1721 		return (0);
1722 	}
1723 
1724 	/*  set options specified by user. */
1725 	if (suser(td) == 0)
1726 		priv = 1;
1727 	if ((error = ip6_setpktoptions(m, opt, priv, 1)) != 0) {
1728 		ip6_clearpktopts(opt, 1, -1); /* XXX: discard all options */
1729 		kfree(opt, M_IP6OPT);
1730 		return (error);
1731 	}
1732 	*pktopt = opt;
1733 	return (0);
1734 }
1735 
1736 /*
1737  * initialize ip6_pktopts.  beware that there are non-zero default values in
1738  * the struct.
1739  */
1740 void
1741 init_ip6pktopts(struct ip6_pktopts *opt)
1742 {
1743 
1744 	bzero(opt, sizeof(*opt));
1745 	opt->ip6po_hlim = -1;	/* -1 means default hop limit */
1746 }
1747 
1748 void
1749 ip6_clearpktopts(struct ip6_pktopts *pktopt, int needfree, int optname)
1750 {
1751 	if (pktopt == NULL)
1752 		return;
1753 
1754 	if (optname == -1) {
1755 		if (needfree && pktopt->ip6po_pktinfo)
1756 			kfree(pktopt->ip6po_pktinfo, M_IP6OPT);
1757 		pktopt->ip6po_pktinfo = NULL;
1758 	}
1759 	if (optname == -1)
1760 		pktopt->ip6po_hlim = -1;
1761 	if (optname == -1) {
1762 		if (needfree && pktopt->ip6po_nexthop)
1763 			kfree(pktopt->ip6po_nexthop, M_IP6OPT);
1764 		pktopt->ip6po_nexthop = NULL;
1765 	}
1766 	if (optname == -1) {
1767 		if (needfree && pktopt->ip6po_hbh)
1768 			kfree(pktopt->ip6po_hbh, M_IP6OPT);
1769 		pktopt->ip6po_hbh = NULL;
1770 	}
1771 	if (optname == -1) {
1772 		if (needfree && pktopt->ip6po_dest1)
1773 			kfree(pktopt->ip6po_dest1, M_IP6OPT);
1774 		pktopt->ip6po_dest1 = NULL;
1775 	}
1776 	if (optname == -1) {
1777 		if (needfree && pktopt->ip6po_rhinfo.ip6po_rhi_rthdr)
1778 			kfree(pktopt->ip6po_rhinfo.ip6po_rhi_rthdr, M_IP6OPT);
1779 		pktopt->ip6po_rhinfo.ip6po_rhi_rthdr = NULL;
1780 		if (pktopt->ip6po_route.ro_rt) {
1781 			RTFREE(pktopt->ip6po_route.ro_rt);
1782 			pktopt->ip6po_route.ro_rt = NULL;
1783 		}
1784 	}
1785 	if (optname == -1) {
1786 		if (needfree && pktopt->ip6po_dest2)
1787 			kfree(pktopt->ip6po_dest2, M_IP6OPT);
1788 		pktopt->ip6po_dest2 = NULL;
1789 	}
1790 }
1791 
1792 #define PKTOPT_EXTHDRCPY(type) \
1793 do {\
1794 	if (src->type) {\
1795 		int hlen =\
1796 			(((struct ip6_ext *)src->type)->ip6e_len + 1) << 3;\
1797 		dst->type = kmalloc(hlen, M_IP6OPT, canwait);\
1798 		if (dst->type == NULL)\
1799 			goto bad;\
1800 		bcopy(src->type, dst->type, hlen);\
1801 	}\
1802 } while (0)
1803 
1804 struct ip6_pktopts *
1805 ip6_copypktopts(struct ip6_pktopts *src, int canwait)
1806 {
1807 	struct ip6_pktopts *dst;
1808 
1809 	if (src == NULL) {
1810 		kprintf("ip6_clearpktopts: invalid argument\n");
1811 		return (NULL);
1812 	}
1813 
1814 	dst = kmalloc(sizeof(*dst), M_IP6OPT, canwait | M_ZERO);
1815 	if (dst == NULL)
1816 		return (NULL);
1817 
1818 	dst->ip6po_hlim = src->ip6po_hlim;
1819 	if (src->ip6po_pktinfo) {
1820 		dst->ip6po_pktinfo = kmalloc(sizeof(*dst->ip6po_pktinfo),
1821 					    M_IP6OPT, canwait);
1822 		if (dst->ip6po_pktinfo == NULL)
1823 			goto bad;
1824 		*dst->ip6po_pktinfo = *src->ip6po_pktinfo;
1825 	}
1826 	if (src->ip6po_nexthop) {
1827 		dst->ip6po_nexthop = kmalloc(src->ip6po_nexthop->sa_len,
1828 					    M_IP6OPT, canwait);
1829 		if (dst->ip6po_nexthop == NULL)
1830 			goto bad;
1831 		bcopy(src->ip6po_nexthop, dst->ip6po_nexthop,
1832 		      src->ip6po_nexthop->sa_len);
1833 	}
1834 	PKTOPT_EXTHDRCPY(ip6po_hbh);
1835 	PKTOPT_EXTHDRCPY(ip6po_dest1);
1836 	PKTOPT_EXTHDRCPY(ip6po_dest2);
1837 	PKTOPT_EXTHDRCPY(ip6po_rthdr); /* not copy the cached route */
1838 	return (dst);
1839 
1840 bad:
1841 	if (dst->ip6po_pktinfo) kfree(dst->ip6po_pktinfo, M_IP6OPT);
1842 	if (dst->ip6po_nexthop) kfree(dst->ip6po_nexthop, M_IP6OPT);
1843 	if (dst->ip6po_hbh) kfree(dst->ip6po_hbh, M_IP6OPT);
1844 	if (dst->ip6po_dest1) kfree(dst->ip6po_dest1, M_IP6OPT);
1845 	if (dst->ip6po_dest2) kfree(dst->ip6po_dest2, M_IP6OPT);
1846 	if (dst->ip6po_rthdr) kfree(dst->ip6po_rthdr, M_IP6OPT);
1847 	kfree(dst, M_IP6OPT);
1848 	return (NULL);
1849 }
1850 #undef PKTOPT_EXTHDRCPY
1851 
1852 void
1853 ip6_freepcbopts(struct ip6_pktopts *pktopt)
1854 {
1855 	if (pktopt == NULL)
1856 		return;
1857 
1858 	ip6_clearpktopts(pktopt, 1, -1);
1859 
1860 	kfree(pktopt, M_IP6OPT);
1861 }
1862 
1863 /*
1864  * Set the IP6 multicast options in response to user setsockopt().
1865  */
1866 static int
1867 ip6_setmoptions(int optname, struct ip6_moptions **im6op, struct mbuf *m)
1868 {
1869 	int error = 0;
1870 	u_int loop, ifindex;
1871 	struct ipv6_mreq *mreq;
1872 	struct ifnet *ifp;
1873 	struct ip6_moptions *im6o = *im6op;
1874 	struct route_in6 ro;
1875 	struct sockaddr_in6 *dst;
1876 	struct in6_multi_mship *imm;
1877 	struct thread *td = curthread;	/* XXX */
1878 
1879 	if (im6o == NULL) {
1880 		/*
1881 		 * No multicast option buffer attached to the pcb;
1882 		 * allocate one and initialize to default values.
1883 		 */
1884 		im6o = (struct ip6_moptions *)
1885 			kmalloc(sizeof(*im6o), M_IPMOPTS, M_WAITOK);
1886 
1887 		*im6op = im6o;
1888 		im6o->im6o_multicast_ifp = NULL;
1889 		im6o->im6o_multicast_hlim = ip6_defmcasthlim;
1890 		im6o->im6o_multicast_loop = IPV6_DEFAULT_MULTICAST_LOOP;
1891 		LIST_INIT(&im6o->im6o_memberships);
1892 	}
1893 
1894 	switch (optname) {
1895 
1896 	case IPV6_MULTICAST_IF:
1897 		/*
1898 		 * Select the interface for outgoing multicast packets.
1899 		 */
1900 		if (m == NULL || m->m_len != sizeof(u_int)) {
1901 			error = EINVAL;
1902 			break;
1903 		}
1904 		bcopy(mtod(m, u_int *), &ifindex, sizeof(ifindex));
1905 		if (ifindex < 0 || if_index < ifindex) {
1906 			error = ENXIO;	/* XXX EINVAL? */
1907 			break;
1908 		}
1909 		ifp = ifindex2ifnet[ifindex];
1910 		if (ifp == NULL || !(ifp->if_flags & IFF_MULTICAST)) {
1911 			error = EADDRNOTAVAIL;
1912 			break;
1913 		}
1914 		im6o->im6o_multicast_ifp = ifp;
1915 		break;
1916 
1917 	case IPV6_MULTICAST_HOPS:
1918 	    {
1919 		/*
1920 		 * Set the IP6 hoplimit for outgoing multicast packets.
1921 		 */
1922 		int optval;
1923 		if (m == NULL || m->m_len != sizeof(int)) {
1924 			error = EINVAL;
1925 			break;
1926 		}
1927 		bcopy(mtod(m, u_int *), &optval, sizeof(optval));
1928 		if (optval < -1 || optval >= 256)
1929 			error = EINVAL;
1930 		else if (optval == -1)
1931 			im6o->im6o_multicast_hlim = ip6_defmcasthlim;
1932 		else
1933 			im6o->im6o_multicast_hlim = optval;
1934 		break;
1935 	    }
1936 
1937 	case IPV6_MULTICAST_LOOP:
1938 		/*
1939 		 * Set the loopback flag for outgoing multicast packets.
1940 		 * Must be zero or one.
1941 		 */
1942 		if (m == NULL || m->m_len != sizeof(u_int)) {
1943 			error = EINVAL;
1944 			break;
1945 		}
1946 		bcopy(mtod(m, u_int *), &loop, sizeof(loop));
1947 		if (loop > 1) {
1948 			error = EINVAL;
1949 			break;
1950 		}
1951 		im6o->im6o_multicast_loop = loop;
1952 		break;
1953 
1954 	case IPV6_JOIN_GROUP:
1955 		/*
1956 		 * Add a multicast group membership.
1957 		 * Group must be a valid IP6 multicast address.
1958 		 */
1959 		if (m == NULL || m->m_len != sizeof(struct ipv6_mreq)) {
1960 			error = EINVAL;
1961 			break;
1962 		}
1963 		mreq = mtod(m, struct ipv6_mreq *);
1964 		if (IN6_IS_ADDR_UNSPECIFIED(&mreq->ipv6mr_multiaddr)) {
1965 			/*
1966 			 * We use the unspecified address to specify to accept
1967 			 * all multicast addresses. Only super user is allowed
1968 			 * to do this.
1969 			 */
1970 			if (suser(td))
1971 			{
1972 				error = EACCES;
1973 				break;
1974 			}
1975 		} else if (!IN6_IS_ADDR_MULTICAST(&mreq->ipv6mr_multiaddr)) {
1976 			error = EINVAL;
1977 			break;
1978 		}
1979 
1980 		/*
1981 		 * If the interface is specified, validate it.
1982 		 */
1983 		if (mreq->ipv6mr_interface < 0
1984 		 || if_index < mreq->ipv6mr_interface) {
1985 			error = ENXIO;	/* XXX EINVAL? */
1986 			break;
1987 		}
1988 		/*
1989 		 * If no interface was explicitly specified, choose an
1990 		 * appropriate one according to the given multicast address.
1991 		 */
1992 		if (mreq->ipv6mr_interface == 0) {
1993 			/*
1994 			 * If the multicast address is in node-local scope,
1995 			 * the interface should be a loopback interface.
1996 			 * Otherwise, look up the routing table for the
1997 			 * address, and choose the outgoing interface.
1998 			 *   XXX: is it a good approach?
1999 			 */
2000 			if (IN6_IS_ADDR_MC_NODELOCAL(&mreq->ipv6mr_multiaddr)) {
2001 				ifp = &loif[0];
2002 			} else {
2003 				ro.ro_rt = NULL;
2004 				dst = (struct sockaddr_in6 *)&ro.ro_dst;
2005 				bzero(dst, sizeof(*dst));
2006 				dst->sin6_len = sizeof(struct sockaddr_in6);
2007 				dst->sin6_family = AF_INET6;
2008 				dst->sin6_addr = mreq->ipv6mr_multiaddr;
2009 				rtalloc((struct route *)&ro);
2010 				if (ro.ro_rt == NULL) {
2011 					error = EADDRNOTAVAIL;
2012 					break;
2013 				}
2014 				ifp = ro.ro_rt->rt_ifp;
2015 				rtfree(ro.ro_rt);
2016 			}
2017 		} else
2018 			ifp = ifindex2ifnet[mreq->ipv6mr_interface];
2019 
2020 		/*
2021 		 * See if we found an interface, and confirm that it
2022 		 * supports multicast
2023 		 */
2024 		if (ifp == NULL || !(ifp->if_flags & IFF_MULTICAST)) {
2025 			error = EADDRNOTAVAIL;
2026 			break;
2027 		}
2028 		/*
2029 		 * Put interface index into the multicast address,
2030 		 * if the address has link-local scope.
2031 		 */
2032 		if (IN6_IS_ADDR_MC_LINKLOCAL(&mreq->ipv6mr_multiaddr)) {
2033 			mreq->ipv6mr_multiaddr.s6_addr16[1]
2034 				= htons(mreq->ipv6mr_interface);
2035 		}
2036 		/*
2037 		 * See if the membership already exists.
2038 		 */
2039 		for (imm = im6o->im6o_memberships.lh_first;
2040 		     imm != NULL; imm = imm->i6mm_chain.le_next)
2041 			if (imm->i6mm_maddr->in6m_ifp == ifp &&
2042 			    IN6_ARE_ADDR_EQUAL(&imm->i6mm_maddr->in6m_addr,
2043 					       &mreq->ipv6mr_multiaddr))
2044 				break;
2045 		if (imm != NULL) {
2046 			error = EADDRINUSE;
2047 			break;
2048 		}
2049 		/*
2050 		 * Everything looks good; add a new record to the multicast
2051 		 * address list for the given interface.
2052 		 */
2053 		imm = kmalloc(sizeof(*imm), M_IPMADDR, M_WAITOK);
2054 		if ((imm->i6mm_maddr =
2055 		     in6_addmulti(&mreq->ipv6mr_multiaddr, ifp, &error)) == NULL) {
2056 			kfree(imm, M_IPMADDR);
2057 			break;
2058 		}
2059 		LIST_INSERT_HEAD(&im6o->im6o_memberships, imm, i6mm_chain);
2060 		break;
2061 
2062 	case IPV6_LEAVE_GROUP:
2063 		/*
2064 		 * Drop a multicast group membership.
2065 		 * Group must be a valid IP6 multicast address.
2066 		 */
2067 		if (m == NULL || m->m_len != sizeof(struct ipv6_mreq)) {
2068 			error = EINVAL;
2069 			break;
2070 		}
2071 		mreq = mtod(m, struct ipv6_mreq *);
2072 		if (IN6_IS_ADDR_UNSPECIFIED(&mreq->ipv6mr_multiaddr)) {
2073 			if (suser(td)) {
2074 				error = EACCES;
2075 				break;
2076 			}
2077 		} else if (!IN6_IS_ADDR_MULTICAST(&mreq->ipv6mr_multiaddr)) {
2078 			error = EINVAL;
2079 			break;
2080 		}
2081 		/*
2082 		 * If an interface address was specified, get a pointer
2083 		 * to its ifnet structure.
2084 		 */
2085 		if (mreq->ipv6mr_interface < 0
2086 		 || if_index < mreq->ipv6mr_interface) {
2087 			error = ENXIO;	/* XXX EINVAL? */
2088 			break;
2089 		}
2090 		ifp = ifindex2ifnet[mreq->ipv6mr_interface];
2091 		/*
2092 		 * Put interface index into the multicast address,
2093 		 * if the address has link-local scope.
2094 		 */
2095 		if (IN6_IS_ADDR_MC_LINKLOCAL(&mreq->ipv6mr_multiaddr)) {
2096 			mreq->ipv6mr_multiaddr.s6_addr16[1]
2097 				= htons(mreq->ipv6mr_interface);
2098 		}
2099 		/*
2100 		 * Find the membership in the membership list.
2101 		 */
2102 		for (imm = im6o->im6o_memberships.lh_first;
2103 		     imm != NULL; imm = imm->i6mm_chain.le_next) {
2104 			if ((ifp == NULL ||
2105 			     imm->i6mm_maddr->in6m_ifp == ifp) &&
2106 			    IN6_ARE_ADDR_EQUAL(&imm->i6mm_maddr->in6m_addr,
2107 					       &mreq->ipv6mr_multiaddr))
2108 				break;
2109 		}
2110 		if (imm == NULL) {
2111 			/* Unable to resolve interface */
2112 			error = EADDRNOTAVAIL;
2113 			break;
2114 		}
2115 		/*
2116 		 * Give up the multicast address record to which the
2117 		 * membership points.
2118 		 */
2119 		LIST_REMOVE(imm, i6mm_chain);
2120 		in6_delmulti(imm->i6mm_maddr);
2121 		kfree(imm, M_IPMADDR);
2122 		break;
2123 
2124 	default:
2125 		error = EOPNOTSUPP;
2126 		break;
2127 	}
2128 
2129 	/*
2130 	 * If all options have default values, no need to keep the mbuf.
2131 	 */
2132 	if (im6o->im6o_multicast_ifp == NULL &&
2133 	    im6o->im6o_multicast_hlim == ip6_defmcasthlim &&
2134 	    im6o->im6o_multicast_loop == IPV6_DEFAULT_MULTICAST_LOOP &&
2135 	    im6o->im6o_memberships.lh_first == NULL) {
2136 		kfree(*im6op, M_IPMOPTS);
2137 		*im6op = NULL;
2138 	}
2139 
2140 	return (error);
2141 }
2142 
2143 /*
2144  * Return the IP6 multicast options in response to user getsockopt().
2145  */
2146 static int
2147 ip6_getmoptions(int optname, struct ip6_moptions *im6o, struct mbuf **mp)
2148 {
2149 	u_int *hlim, *loop, *ifindex;
2150 
2151 	*mp = m_get(MB_WAIT, MT_HEADER);		/* XXX */
2152 
2153 	switch (optname) {
2154 
2155 	case IPV6_MULTICAST_IF:
2156 		ifindex = mtod(*mp, u_int *);
2157 		(*mp)->m_len = sizeof(u_int);
2158 		if (im6o == NULL || im6o->im6o_multicast_ifp == NULL)
2159 			*ifindex = 0;
2160 		else
2161 			*ifindex = im6o->im6o_multicast_ifp->if_index;
2162 		return (0);
2163 
2164 	case IPV6_MULTICAST_HOPS:
2165 		hlim = mtod(*mp, u_int *);
2166 		(*mp)->m_len = sizeof(u_int);
2167 		if (im6o == NULL)
2168 			*hlim = ip6_defmcasthlim;
2169 		else
2170 			*hlim = im6o->im6o_multicast_hlim;
2171 		return (0);
2172 
2173 	case IPV6_MULTICAST_LOOP:
2174 		loop = mtod(*mp, u_int *);
2175 		(*mp)->m_len = sizeof(u_int);
2176 		if (im6o == NULL)
2177 			*loop = ip6_defmcasthlim;
2178 		else
2179 			*loop = im6o->im6o_multicast_loop;
2180 		return (0);
2181 
2182 	default:
2183 		return (EOPNOTSUPP);
2184 	}
2185 }
2186 
2187 /*
2188  * Discard the IP6 multicast options.
2189  */
2190 void
2191 ip6_freemoptions(struct ip6_moptions *im6o)
2192 {
2193 	struct in6_multi_mship *imm;
2194 
2195 	if (im6o == NULL)
2196 		return;
2197 
2198 	while ((imm = im6o->im6o_memberships.lh_first) != NULL) {
2199 		LIST_REMOVE(imm, i6mm_chain);
2200 		if (imm->i6mm_maddr)
2201 			in6_delmulti(imm->i6mm_maddr);
2202 		kfree(imm, M_IPMADDR);
2203 	}
2204 	kfree(im6o, M_IPMOPTS);
2205 }
2206 
2207 /*
2208  * Set IPv6 outgoing packet options based on advanced API.
2209  */
2210 int
2211 ip6_setpktoptions(struct mbuf *control, struct ip6_pktopts *opt, int priv,
2212 		  int needcopy)
2213 {
2214 	struct cmsghdr *cm = NULL;
2215 
2216 	if (control == NULL || opt == NULL)
2217 		return (EINVAL);
2218 
2219 	init_ip6pktopts(opt);
2220 
2221 	/*
2222 	 * XXX: Currently, we assume all the optional information is stored
2223 	 * in a single mbuf.
2224 	 */
2225 	if (control->m_next)
2226 		return (EINVAL);
2227 
2228 	for (; control->m_len; control->m_data += CMSG_ALIGN(cm->cmsg_len),
2229 		     control->m_len -= CMSG_ALIGN(cm->cmsg_len)) {
2230 		cm = mtod(control, struct cmsghdr *);
2231 		if (cm->cmsg_len == 0 || cm->cmsg_len > control->m_len)
2232 			return (EINVAL);
2233 		if (cm->cmsg_level != IPPROTO_IPV6)
2234 			continue;
2235 
2236 		/*
2237 		 * XXX should check if RFC2292 API is mixed with 2292bis API
2238 		 */
2239 		switch (cm->cmsg_type) {
2240 		case IPV6_PKTINFO:
2241 			if (cm->cmsg_len != CMSG_LEN(sizeof(struct in6_pktinfo)))
2242 				return (EINVAL);
2243 			if (needcopy) {
2244 				/* XXX: Is it really WAITOK? */
2245 				opt->ip6po_pktinfo =
2246 					kmalloc(sizeof(struct in6_pktinfo),
2247 					       M_IP6OPT, M_WAITOK);
2248 				bcopy(CMSG_DATA(cm), opt->ip6po_pktinfo,
2249 				    sizeof(struct in6_pktinfo));
2250 			} else
2251 				opt->ip6po_pktinfo =
2252 					(struct in6_pktinfo *)CMSG_DATA(cm);
2253 			if (opt->ip6po_pktinfo->ipi6_ifindex &&
2254 			    IN6_IS_ADDR_LINKLOCAL(&opt->ip6po_pktinfo->ipi6_addr))
2255 				opt->ip6po_pktinfo->ipi6_addr.s6_addr16[1] =
2256 					htons(opt->ip6po_pktinfo->ipi6_ifindex);
2257 
2258 			if (opt->ip6po_pktinfo->ipi6_ifindex > if_index
2259 			 || opt->ip6po_pktinfo->ipi6_ifindex < 0) {
2260 				return (ENXIO);
2261 			}
2262 
2263 			/*
2264 			 * Check if the requested source address is indeed a
2265 			 * unicast address assigned to the node, and can be
2266 			 * used as the packet's source address.
2267 			 */
2268 			if (!IN6_IS_ADDR_UNSPECIFIED(&opt->ip6po_pktinfo->ipi6_addr)) {
2269 				struct in6_ifaddr *ia6;
2270 				struct sockaddr_in6 sin6;
2271 
2272 				bzero(&sin6, sizeof(sin6));
2273 				sin6.sin6_len = sizeof(sin6);
2274 				sin6.sin6_family = AF_INET6;
2275 				sin6.sin6_addr =
2276 					opt->ip6po_pktinfo->ipi6_addr;
2277 				ia6 = (struct in6_ifaddr *)ifa_ifwithaddr(sin6tosa(&sin6));
2278 				if (ia6 == NULL ||
2279 				    (ia6->ia6_flags & (IN6_IFF_ANYCAST |
2280 						       IN6_IFF_NOTREADY)) != 0)
2281 					return (EADDRNOTAVAIL);
2282 			}
2283 			break;
2284 
2285 		case IPV6_HOPLIMIT:
2286 			if (cm->cmsg_len != CMSG_LEN(sizeof(int)))
2287 				return (EINVAL);
2288 
2289 			opt->ip6po_hlim = *(int *)CMSG_DATA(cm);
2290 			if (opt->ip6po_hlim < -1 || opt->ip6po_hlim > 255)
2291 				return (EINVAL);
2292 			break;
2293 
2294 		case IPV6_NEXTHOP:
2295 			if (!priv)
2296 				return (EPERM);
2297 
2298 			if (cm->cmsg_len < sizeof(u_char) ||
2299 			    /* check if cmsg_len is large enough for sa_len */
2300 			    cm->cmsg_len < CMSG_LEN(*CMSG_DATA(cm)))
2301 				return (EINVAL);
2302 
2303 			if (needcopy) {
2304 				opt->ip6po_nexthop =
2305 					kmalloc(*CMSG_DATA(cm),
2306 					       M_IP6OPT, M_WAITOK);
2307 				bcopy(CMSG_DATA(cm),
2308 				      opt->ip6po_nexthop,
2309 				      *CMSG_DATA(cm));
2310 			} else
2311 				opt->ip6po_nexthop =
2312 					(struct sockaddr *)CMSG_DATA(cm);
2313 			break;
2314 
2315 		case IPV6_HOPOPTS:
2316 		{
2317 			struct ip6_hbh *hbh;
2318 			int hbhlen;
2319 
2320 			if (cm->cmsg_len < CMSG_LEN(sizeof(struct ip6_hbh)))
2321 				return (EINVAL);
2322 			hbh = (struct ip6_hbh *)CMSG_DATA(cm);
2323 			hbhlen = (hbh->ip6h_len + 1) << 3;
2324 			if (cm->cmsg_len != CMSG_LEN(hbhlen))
2325 				return (EINVAL);
2326 
2327 			if (needcopy) {
2328 				opt->ip6po_hbh =
2329 					kmalloc(hbhlen, M_IP6OPT, M_WAITOK);
2330 				bcopy(hbh, opt->ip6po_hbh, hbhlen);
2331 			} else
2332 				opt->ip6po_hbh = hbh;
2333 			break;
2334 		}
2335 
2336 		case IPV6_DSTOPTS:
2337 		{
2338 			struct ip6_dest *dest, **newdest;
2339 			int destlen;
2340 
2341 			if (cm->cmsg_len < CMSG_LEN(sizeof(struct ip6_dest)))
2342 				return (EINVAL);
2343 			dest = (struct ip6_dest *)CMSG_DATA(cm);
2344 			destlen = (dest->ip6d_len + 1) << 3;
2345 			if (cm->cmsg_len != CMSG_LEN(destlen))
2346 				return (EINVAL);
2347 
2348 			/*
2349 			 * The old advacned API is ambiguous on this
2350 			 * point. Our approach is to determine the
2351 			 * position based according to the existence
2352 			 * of a routing header. Note, however, that
2353 			 * this depends on the order of the extension
2354 			 * headers in the ancillary data; the 1st part
2355 			 * of the destination options header must
2356 			 * appear before the routing header in the
2357 			 * ancillary data, too.
2358 			 * RFC2292bis solved the ambiguity by
2359 			 * introducing separate cmsg types.
2360 			 */
2361 			if (opt->ip6po_rthdr == NULL)
2362 				newdest = &opt->ip6po_dest1;
2363 			else
2364 				newdest = &opt->ip6po_dest2;
2365 
2366 			if (needcopy) {
2367 				*newdest = kmalloc(destlen, M_IP6OPT, M_WAITOK);
2368 				bcopy(dest, *newdest, destlen);
2369 			} else
2370 				*newdest = dest;
2371 
2372 			break;
2373 		}
2374 
2375 		case IPV6_RTHDR:
2376 		{
2377 			struct ip6_rthdr *rth;
2378 			int rthlen;
2379 
2380 			if (cm->cmsg_len < CMSG_LEN(sizeof(struct ip6_rthdr)))
2381 				return (EINVAL);
2382 			rth = (struct ip6_rthdr *)CMSG_DATA(cm);
2383 			rthlen = (rth->ip6r_len + 1) << 3;
2384 			if (cm->cmsg_len != CMSG_LEN(rthlen))
2385 				return (EINVAL);
2386 
2387 			switch (rth->ip6r_type) {
2388 			case IPV6_RTHDR_TYPE_0:
2389 				/* must contain one addr */
2390 				if (rth->ip6r_len == 0)
2391 					return (EINVAL);
2392 				/* length must be even */
2393 				if (rth->ip6r_len % 2)
2394 					return (EINVAL);
2395 				if (rth->ip6r_len / 2 != rth->ip6r_segleft)
2396 					return (EINVAL);
2397 				break;
2398 			default:
2399 				return (EINVAL);	/* not supported */
2400 			}
2401 
2402 			if (needcopy) {
2403 				opt->ip6po_rthdr = kmalloc(rthlen, M_IP6OPT,
2404 							  M_WAITOK);
2405 				bcopy(rth, opt->ip6po_rthdr, rthlen);
2406 			} else
2407 				opt->ip6po_rthdr = rth;
2408 
2409 			break;
2410 		}
2411 
2412 		default:
2413 			return (ENOPROTOOPT);
2414 		}
2415 	}
2416 
2417 	return (0);
2418 }
2419 
2420 /*
2421  * Routine called from ip6_output() to loop back a copy of an IP6 multicast
2422  * packet to the input queue of a specified interface.  Note that this
2423  * calls the output routine of the loopback "driver", but with an interface
2424  * pointer that might NOT be &loif -- easier than replicating that code here.
2425  */
2426 void
2427 ip6_mloopback(struct ifnet *ifp, struct mbuf *m, struct sockaddr_in6 *dst)
2428 {
2429 	struct mbuf *copym;
2430 	struct ip6_hdr *ip6;
2431 
2432 	copym = m_copy(m, 0, M_COPYALL);
2433 	if (copym == NULL)
2434 		return;
2435 
2436 	/*
2437 	 * Make sure to deep-copy IPv6 header portion in case the data
2438 	 * is in an mbuf cluster, so that we can safely override the IPv6
2439 	 * header portion later.
2440 	 */
2441 	if ((copym->m_flags & M_EXT) != 0 ||
2442 	    copym->m_len < sizeof(struct ip6_hdr)) {
2443 		copym = m_pullup(copym, sizeof(struct ip6_hdr));
2444 		if (copym == NULL)
2445 			return;
2446 	}
2447 
2448 #ifdef DIAGNOSTIC
2449 	if (copym->m_len < sizeof(*ip6)) {
2450 		m_freem(copym);
2451 		return;
2452 	}
2453 #endif
2454 
2455 	ip6 = mtod(copym, struct ip6_hdr *);
2456 	/*
2457 	 * clear embedded scope identifiers if necessary.
2458 	 * in6_clearscope will touch the addresses only when necessary.
2459 	 */
2460 	in6_clearscope(&ip6->ip6_src);
2461 	in6_clearscope(&ip6->ip6_dst);
2462 
2463 	if_simloop(ifp, copym, dst->sin6_family, 0);
2464 }
2465 
2466 /*
2467  * Separate the IPv6 header from the payload into its own mbuf.
2468  *
2469  * Returns the new mbuf chain or the original mbuf if no payload.
2470  * Returns NULL if can't allocate new mbuf for header.
2471  */
2472 static struct mbuf *
2473 ip6_splithdr(struct mbuf *m)
2474 {
2475 	struct mbuf *mh;
2476 
2477 	if (m->m_len <= sizeof(struct ip6_hdr))		/* no payload */
2478 		return (m);
2479 
2480 	MGETHDR(mh, MB_DONTWAIT, MT_HEADER);
2481 	if (mh == NULL)
2482 		return (NULL);
2483 	mh->m_len = sizeof(struct ip6_hdr);
2484 	M_MOVE_PKTHDR(mh, m);
2485 	MH_ALIGN(mh, sizeof(struct ip6_hdr));
2486 	bcopy(mtod(m, caddr_t), mtod(mh, caddr_t), sizeof(struct ip6_hdr));
2487 	m->m_data += sizeof(struct ip6_hdr);
2488 	m->m_len -= sizeof(struct ip6_hdr);
2489 	mh->m_next = m;
2490 	return (mh);
2491 }
2492 
2493 /*
2494  * Compute IPv6 extension header length.
2495  */
2496 int
2497 ip6_optlen(struct in6pcb *in6p)
2498 {
2499 	int len;
2500 
2501 	if (!in6p->in6p_outputopts)
2502 		return 0;
2503 
2504 	len = 0;
2505 #define elen(x) \
2506     (((struct ip6_ext *)(x)) ? (((struct ip6_ext *)(x))->ip6e_len + 1) << 3 : 0)
2507 
2508 	len += elen(in6p->in6p_outputopts->ip6po_hbh);
2509 	if (in6p->in6p_outputopts->ip6po_rthdr)
2510 		/* dest1 is valid with rthdr only */
2511 		len += elen(in6p->in6p_outputopts->ip6po_dest1);
2512 	len += elen(in6p->in6p_outputopts->ip6po_rthdr);
2513 	len += elen(in6p->in6p_outputopts->ip6po_dest2);
2514 	return len;
2515 #undef elen
2516 }
2517