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ip6_output.c revision 1.128.2.1
      1 /*	$NetBSD: ip6_output.c,v 1.128.2.1 2008/05/18 12:35:35 yamt 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 1.128.2.1 2008/05/18 12:35:35 yamt 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/in6_offload.h>
     95 #include <netinet6/ip6_var.h>
     96 #include <netinet6/ip6_private.h>
     97 #include <netinet6/in6_pcb.h>
     98 #include <netinet6/nd6.h>
     99 #include <netinet6/ip6protosw.h>
    100 #include <netinet6/scope6_var.h>
    101 
    102 #ifdef IPSEC
    103 #include <netinet6/ipsec.h>
    104 #include <netinet6/ipsec_private.h>
    105 #include <netkey/key.h>
    106 #endif /* IPSEC */
    107 
    108 #ifdef FAST_IPSEC
    109 #include <netipsec/ipsec.h>
    110 #include <netipsec/ipsec6.h>
    111 #include <netipsec/key.h>
    112 #include <netipsec/xform.h>
    113 #endif
    114 
    115 
    116 #include <net/net_osdep.h>
    117 
    118 #ifdef PFIL_HOOKS
    119 extern struct pfil_head inet6_pfil_hook;	/* XXX */
    120 #endif
    121 
    122 struct ip6_exthdrs {
    123 	struct mbuf *ip6e_ip6;
    124 	struct mbuf *ip6e_hbh;
    125 	struct mbuf *ip6e_dest1;
    126 	struct mbuf *ip6e_rthdr;
    127 	struct mbuf *ip6e_dest2;
    128 };
    129 
    130 static int ip6_pcbopt(int, u_char *, int, struct ip6_pktopts **,
    131 	int, int);
    132 static int ip6_getpcbopt(struct ip6_pktopts *, int, struct mbuf **);
    133 static int ip6_setpktopt(int, u_char *, int, struct ip6_pktopts *, int,
    134 	int, int, int);
    135 static int ip6_setmoptions(int, struct ip6_moptions **, struct mbuf *);
    136 static int ip6_getmoptions(int, struct ip6_moptions *, struct mbuf **);
    137 static int ip6_copyexthdr(struct mbuf **, void *, int);
    138 static int ip6_insertfraghdr(struct mbuf *, struct mbuf *, int,
    139 	struct ip6_frag **);
    140 static int ip6_insert_jumboopt(struct ip6_exthdrs *, u_int32_t);
    141 static int ip6_splithdr(struct mbuf *, struct ip6_exthdrs *);
    142 static int ip6_getpmtu(struct route *, struct route *, struct ifnet *,
    143     const struct in6_addr *, u_long *, int *);
    144 static int copypktopts(struct ip6_pktopts *, struct ip6_pktopts *, int);
    145 
    146 #ifdef RFC2292
    147 static int ip6_pcbopts(struct ip6_pktopts **, struct mbuf *,
    148 	struct socket *);
    149 #endif
    150 
    151 #define	IN6_NEED_CHECKSUM(ifp, csum_flags) \
    152 	(__predict_true(((ifp)->if_flags & IFF_LOOPBACK) == 0 || \
    153 	(((csum_flags) & M_CSUM_UDPv6) != 0 && udp_do_loopback_cksum) || \
    154 	(((csum_flags) & M_CSUM_TCPv6) != 0 && tcp_do_loopback_cksum)))
    155 
    156 /*
    157  * IP6 output. The packet in mbuf chain m contains a skeletal IP6
    158  * header (with pri, len, nxt, hlim, src, dst).
    159  * This function may modify ver and hlim only.
    160  * The mbuf chain containing the packet will be freed.
    161  * The mbuf opt, if present, will not be freed.
    162  *
    163  * type of "mtu": rt_rmx.rmx_mtu is u_long, ifnet.ifr_mtu is int, and
    164  * nd_ifinfo.linkmtu is u_int32_t.  so we use u_long to hold largest one,
    165  * which is rt_rmx.rmx_mtu.
    166  */
    167 int
    168 ip6_output(
    169     struct mbuf *m0,
    170     struct ip6_pktopts *opt,
    171     struct route *ro,
    172     int flags,
    173     struct ip6_moptions *im6o,
    174     struct socket *so,
    175     struct ifnet **ifpp		/* XXX: just for statistics */
    176 )
    177 {
    178 	struct ip6_hdr *ip6, *mhip6;
    179 	struct ifnet *ifp, *origifp;
    180 	struct mbuf *m = m0;
    181 	int hlen, tlen, len, off;
    182 	bool tso;
    183 	struct route ip6route;
    184 	struct rtentry *rt = NULL;
    185 	const struct sockaddr_in6 *dst = NULL;
    186 	struct sockaddr_in6 src_sa, dst_sa;
    187 	int error = 0;
    188 	struct in6_ifaddr *ia = NULL;
    189 	u_long mtu;
    190 	int alwaysfrag, dontfrag;
    191 	u_int32_t optlen = 0, plen = 0, unfragpartlen = 0;
    192 	struct ip6_exthdrs exthdrs;
    193 	struct in6_addr finaldst, src0, dst0;
    194 	u_int32_t zone;
    195 	struct route *ro_pmtu = NULL;
    196 	int hdrsplit = 0;
    197 	int needipsec = 0;
    198 #ifdef IPSEC
    199 	int needipsectun = 0;
    200 	struct secpolicy *sp = NULL;
    201 
    202 	ip6 = mtod(m, struct ip6_hdr *);
    203 #endif /* IPSEC */
    204 #ifdef FAST_IPSEC
    205 	struct secpolicy *sp = NULL;
    206 	int s;
    207 #endif
    208 
    209 	memset(&ip6route, 0, sizeof(ip6route));
    210 
    211 #ifdef  DIAGNOSTIC
    212 	if ((m->m_flags & M_PKTHDR) == 0)
    213 		panic("ip6_output: no HDR");
    214 
    215 	if ((m->m_pkthdr.csum_flags &
    216 	    (M_CSUM_TCPv4|M_CSUM_UDPv4|M_CSUM_TSOv4)) != 0) {
    217 		panic("ip6_output: IPv4 checksum offload flags: %d",
    218 		    m->m_pkthdr.csum_flags);
    219 	}
    220 
    221 	if ((m->m_pkthdr.csum_flags & (M_CSUM_TCPv6|M_CSUM_UDPv6)) ==
    222 	    (M_CSUM_TCPv6|M_CSUM_UDPv6)) {
    223 		panic("ip6_output: conflicting checksum offload flags: %d",
    224 		    m->m_pkthdr.csum_flags);
    225 	}
    226 #endif
    227 
    228 	M_CSUM_DATA_IPv6_HL_SET(m->m_pkthdr.csum_data, sizeof(struct ip6_hdr));
    229 
    230 #define MAKE_EXTHDR(hp, mp)						\
    231     do {								\
    232 	if (hp) {							\
    233 		struct ip6_ext *eh = (struct ip6_ext *)(hp);		\
    234 		error = ip6_copyexthdr((mp), (void *)(hp), 		\
    235 		    ((eh)->ip6e_len + 1) << 3);				\
    236 		if (error)						\
    237 			goto freehdrs;					\
    238 	}								\
    239     } while (/*CONSTCOND*/ 0)
    240 
    241 	bzero(&exthdrs, sizeof(exthdrs));
    242 	if (opt) {
    243 		/* Hop-by-Hop options header */
    244 		MAKE_EXTHDR(opt->ip6po_hbh, &exthdrs.ip6e_hbh);
    245 		/* Destination options header(1st part) */
    246 		MAKE_EXTHDR(opt->ip6po_dest1, &exthdrs.ip6e_dest1);
    247 		/* Routing header */
    248 		MAKE_EXTHDR(opt->ip6po_rthdr, &exthdrs.ip6e_rthdr);
    249 		/* Destination options header(2nd part) */
    250 		MAKE_EXTHDR(opt->ip6po_dest2, &exthdrs.ip6e_dest2);
    251 	}
    252 
    253 #ifdef IPSEC
    254 	if ((flags & IPV6_FORWARDING) != 0) {
    255 		needipsec = 0;
    256 		goto skippolicycheck;
    257 	}
    258 
    259 	/* get a security policy for this packet */
    260 	if (so == NULL)
    261 		sp = ipsec6_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, 0, &error);
    262 	else {
    263 		if (IPSEC_PCB_SKIP_IPSEC(sotoinpcb_hdr(so)->inph_sp,
    264 					 IPSEC_DIR_OUTBOUND)) {
    265 			needipsec = 0;
    266 			goto skippolicycheck;
    267 		}
    268 		sp = ipsec6_getpolicybysock(m, IPSEC_DIR_OUTBOUND, so, &error);
    269 	}
    270 
    271 	if (sp == NULL) {
    272 		IPSEC6_STATINC(IPSEC_STAT_OUT_INVAL);
    273 		goto freehdrs;
    274 	}
    275 
    276 	error = 0;
    277 
    278 	/* check policy */
    279 	switch (sp->policy) {
    280 	case IPSEC_POLICY_DISCARD:
    281 		/*
    282 		 * This packet is just discarded.
    283 		 */
    284 		IPSEC6_STATINC(IPSEC_STAT_OUT_POLVIO);
    285 		goto freehdrs;
    286 
    287 	case IPSEC_POLICY_BYPASS:
    288 	case IPSEC_POLICY_NONE:
    289 		/* no need to do IPsec. */
    290 		needipsec = 0;
    291 		break;
    292 
    293 	case IPSEC_POLICY_IPSEC:
    294 		if (sp->req == NULL) {
    295 			/* XXX should be panic ? */
    296 			printf("ip6_output: No IPsec request specified.\n");
    297 			error = EINVAL;
    298 			goto freehdrs;
    299 		}
    300 		needipsec = 1;
    301 		break;
    302 
    303 	case IPSEC_POLICY_ENTRUST:
    304 	default:
    305 		printf("ip6_output: Invalid policy found. %d\n", sp->policy);
    306 	}
    307 
    308   skippolicycheck:;
    309 #endif /* IPSEC */
    310 
    311 	/*
    312 	 * Calculate the total length of the extension header chain.
    313 	 * Keep the length of the unfragmentable part for fragmentation.
    314 	 */
    315 	optlen = 0;
    316 	if (exthdrs.ip6e_hbh) optlen += exthdrs.ip6e_hbh->m_len;
    317 	if (exthdrs.ip6e_dest1) optlen += exthdrs.ip6e_dest1->m_len;
    318 	if (exthdrs.ip6e_rthdr) optlen += exthdrs.ip6e_rthdr->m_len;
    319 	unfragpartlen = optlen + sizeof(struct ip6_hdr);
    320 	/* NOTE: we don't add AH/ESP length here. do that later. */
    321 	if (exthdrs.ip6e_dest2) optlen += exthdrs.ip6e_dest2->m_len;
    322 
    323 #ifdef FAST_IPSEC
    324 	/* Check the security policy (SP) for the packet */
    325 
    326 	/* XXX For moment, we doesn't support packet with extented action */
    327 	if (optlen !=0)
    328 		goto freehdrs;
    329 
    330 	sp = ipsec6_check_policy(m,so,flags,&needipsec,&error);
    331 	if (error != 0) {
    332 		/*
    333 		 * Hack: -EINVAL is used to signal that a packet
    334 		 * should be silently discarded.  This is typically
    335 		 * because we asked key management for an SA and
    336 		 * it was delayed (e.g. kicked up to IKE).
    337 		 */
    338 	if (error == -EINVAL)
    339 		error = 0;
    340 	goto freehdrs;
    341     }
    342 #endif /* FAST_IPSEC */
    343 
    344 
    345 	if (needipsec &&
    346 	    (m->m_pkthdr.csum_flags & (M_CSUM_UDPv6|M_CSUM_TCPv6)) != 0) {
    347 		in6_delayed_cksum(m);
    348 		m->m_pkthdr.csum_flags &= ~(M_CSUM_UDPv6|M_CSUM_TCPv6);
    349 	}
    350 
    351 
    352 	/*
    353 	 * If we need IPsec, or there is at least one extension header,
    354 	 * separate IP6 header from the payload.
    355 	 */
    356 	if ((needipsec || optlen) && !hdrsplit) {
    357 		if ((error = ip6_splithdr(m, &exthdrs)) != 0) {
    358 			m = NULL;
    359 			goto freehdrs;
    360 		}
    361 		m = exthdrs.ip6e_ip6;
    362 		hdrsplit++;
    363 	}
    364 
    365 	/* adjust pointer */
    366 	ip6 = mtod(m, struct ip6_hdr *);
    367 
    368 	/* adjust mbuf packet header length */
    369 	m->m_pkthdr.len += optlen;
    370 	plen = m->m_pkthdr.len - sizeof(*ip6);
    371 
    372 	/* If this is a jumbo payload, insert a jumbo payload option. */
    373 	if (plen > IPV6_MAXPACKET) {
    374 		if (!hdrsplit) {
    375 			if ((error = ip6_splithdr(m, &exthdrs)) != 0) {
    376 				m = NULL;
    377 				goto freehdrs;
    378 			}
    379 			m = exthdrs.ip6e_ip6;
    380 			hdrsplit++;
    381 		}
    382 		/* adjust pointer */
    383 		ip6 = mtod(m, struct ip6_hdr *);
    384 		if ((error = ip6_insert_jumboopt(&exthdrs, plen)) != 0)
    385 			goto freehdrs;
    386 		optlen += 8; /* XXX JUMBOOPTLEN */
    387 		ip6->ip6_plen = 0;
    388 	} else
    389 		ip6->ip6_plen = htons(plen);
    390 
    391 	/*
    392 	 * Concatenate headers and fill in next header fields.
    393 	 * Here we have, on "m"
    394 	 *	IPv6 payload
    395 	 * and we insert headers accordingly.  Finally, we should be getting:
    396 	 *	IPv6 hbh dest1 rthdr ah* [esp* dest2 payload]
    397 	 *
    398 	 * during the header composing process, "m" points to IPv6 header.
    399 	 * "mprev" points to an extension header prior to esp.
    400 	 */
    401 	{
    402 		u_char *nexthdrp = &ip6->ip6_nxt;
    403 		struct mbuf *mprev = m;
    404 
    405 		/*
    406 		 * we treat dest2 specially.  this makes IPsec processing
    407 		 * much easier.  the goal here is to make mprev point the
    408 		 * mbuf prior to dest2.
    409 		 *
    410 		 * result: IPv6 dest2 payload
    411 		 * m and mprev will point to IPv6 header.
    412 		 */
    413 		if (exthdrs.ip6e_dest2) {
    414 			if (!hdrsplit)
    415 				panic("assumption failed: hdr not split");
    416 			exthdrs.ip6e_dest2->m_next = m->m_next;
    417 			m->m_next = exthdrs.ip6e_dest2;
    418 			*mtod(exthdrs.ip6e_dest2, u_char *) = ip6->ip6_nxt;
    419 			ip6->ip6_nxt = IPPROTO_DSTOPTS;
    420 		}
    421 
    422 #define MAKE_CHAIN(m, mp, p, i)\
    423     do {\
    424 	if (m) {\
    425 		if (!hdrsplit) \
    426 			panic("assumption failed: hdr not split"); \
    427 		*mtod((m), u_char *) = *(p);\
    428 		*(p) = (i);\
    429 		p = mtod((m), u_char *);\
    430 		(m)->m_next = (mp)->m_next;\
    431 		(mp)->m_next = (m);\
    432 		(mp) = (m);\
    433 	}\
    434     } while (/*CONSTCOND*/ 0)
    435 		/*
    436 		 * result: IPv6 hbh dest1 rthdr dest2 payload
    437 		 * m will point to IPv6 header.  mprev will point to the
    438 		 * extension header prior to dest2 (rthdr in the above case).
    439 		 */
    440 		MAKE_CHAIN(exthdrs.ip6e_hbh, mprev, nexthdrp, IPPROTO_HOPOPTS);
    441 		MAKE_CHAIN(exthdrs.ip6e_dest1, mprev, nexthdrp,
    442 		    IPPROTO_DSTOPTS);
    443 		MAKE_CHAIN(exthdrs.ip6e_rthdr, mprev, nexthdrp,
    444 		    IPPROTO_ROUTING);
    445 
    446 		M_CSUM_DATA_IPv6_HL_SET(m->m_pkthdr.csum_data,
    447 		    sizeof(struct ip6_hdr) + optlen);
    448 
    449 #ifdef IPSEC
    450 		if (!needipsec)
    451 			goto skip_ipsec2;
    452 
    453 		/*
    454 		 * pointers after IPsec headers are not valid any more.
    455 		 * other pointers need a great care too.
    456 		 * (IPsec routines should not mangle mbufs prior to AH/ESP)
    457 		 */
    458 		exthdrs.ip6e_dest2 = NULL;
    459 
    460 	    {
    461 		struct ip6_rthdr *rh = NULL;
    462 		int segleft_org = 0;
    463 		struct ipsec_output_state state;
    464 
    465 		if (exthdrs.ip6e_rthdr) {
    466 			rh = mtod(exthdrs.ip6e_rthdr, struct ip6_rthdr *);
    467 			segleft_org = rh->ip6r_segleft;
    468 			rh->ip6r_segleft = 0;
    469 		}
    470 
    471 		bzero(&state, sizeof(state));
    472 		state.m = m;
    473 		error = ipsec6_output_trans(&state, nexthdrp, mprev, sp, flags,
    474 		    &needipsectun);
    475 		m = state.m;
    476 		if (error) {
    477 			rh = mtod(exthdrs.ip6e_rthdr, struct ip6_rthdr *);
    478 			/* mbuf is already reclaimed in ipsec6_output_trans. */
    479 			m = NULL;
    480 			switch (error) {
    481 			case EHOSTUNREACH:
    482 			case ENETUNREACH:
    483 			case EMSGSIZE:
    484 			case ENOBUFS:
    485 			case ENOMEM:
    486 				break;
    487 			default:
    488 				printf("ip6_output (ipsec): error code %d\n", error);
    489 				/* FALLTHROUGH */
    490 			case ENOENT:
    491 				/* don't show these error codes to the user */
    492 				error = 0;
    493 				break;
    494 			}
    495 			goto bad;
    496 		}
    497 		if (exthdrs.ip6e_rthdr) {
    498 			/* ah6_output doesn't modify mbuf chain */
    499 			rh->ip6r_segleft = segleft_org;
    500 		}
    501 	    }
    502 skip_ipsec2:;
    503 #endif
    504 	}
    505 
    506 	/*
    507 	 * If there is a routing header, replace destination address field
    508 	 * with the first hop of the routing header.
    509 	 */
    510 	if (exthdrs.ip6e_rthdr) {
    511 		struct ip6_rthdr *rh;
    512 		struct ip6_rthdr0 *rh0;
    513 		struct in6_addr *addr;
    514 		struct sockaddr_in6 sa;
    515 
    516 		rh = (struct ip6_rthdr *)(mtod(exthdrs.ip6e_rthdr,
    517 		    struct ip6_rthdr *));
    518 		finaldst = ip6->ip6_dst;
    519 		switch (rh->ip6r_type) {
    520 		case IPV6_RTHDR_TYPE_0:
    521 			 rh0 = (struct ip6_rthdr0 *)rh;
    522 			 addr = (struct in6_addr *)(rh0 + 1);
    523 
    524 			 /*
    525 			  * construct a sockaddr_in6 form of
    526 			  * the first hop.
    527 			  *
    528 			  * XXX: we may not have enough
    529 			  * information about its scope zone;
    530 			  * there is no standard API to pass
    531 			  * the information from the
    532 			  * application.
    533 			  */
    534 			 sockaddr_in6_init(&sa, addr, 0, 0, 0);
    535 			 if ((error = sa6_embedscope(&sa,
    536 			     ip6_use_defzone)) != 0) {
    537 				 goto bad;
    538 			 }
    539 			 ip6->ip6_dst = sa.sin6_addr;
    540 			 (void)memmove(&addr[0], &addr[1],
    541 			     sizeof(struct in6_addr) *
    542 			     (rh0->ip6r0_segleft - 1));
    543 			 addr[rh0->ip6r0_segleft - 1] = finaldst;
    544 			 /* XXX */
    545 			 in6_clearscope(addr + rh0->ip6r0_segleft - 1);
    546 			 break;
    547 		default:	/* is it possible? */
    548 			 error = EINVAL;
    549 			 goto bad;
    550 		}
    551 	}
    552 
    553 	/* Source address validation */
    554 	if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) &&
    555 	    (flags & IPV6_UNSPECSRC) == 0) {
    556 		error = EOPNOTSUPP;
    557 		IP6_STATINC(IP6_STAT_BADSCOPE);
    558 		goto bad;
    559 	}
    560 	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_src)) {
    561 		error = EOPNOTSUPP;
    562 		IP6_STATINC(IP6_STAT_BADSCOPE);
    563 		goto bad;
    564 	}
    565 
    566 	IP6_STATINC(IP6_STAT_LOCALOUT);
    567 
    568 	/*
    569 	 * Route packet.
    570 	 */
    571 	/* initialize cached route */
    572 	if (ro == NULL) {
    573 		ro = &ip6route;
    574 	}
    575 	ro_pmtu = ro;
    576 	if (opt && opt->ip6po_rthdr)
    577 		ro = &opt->ip6po_route;
    578 
    579  	/*
    580 	 * if specified, try to fill in the traffic class field.
    581 	 * do not override if a non-zero value is already set.
    582 	 * we check the diffserv field and the ecn field separately.
    583 	 */
    584 	if (opt && opt->ip6po_tclass >= 0) {
    585 		int mask = 0;
    586 
    587 		if ((ip6->ip6_flow & htonl(0xfc << 20)) == 0)
    588 			mask |= 0xfc;
    589 		if ((ip6->ip6_flow & htonl(0x03 << 20)) == 0)
    590 			mask |= 0x03;
    591 		if (mask != 0)
    592 			ip6->ip6_flow |= htonl((opt->ip6po_tclass & mask) << 20);
    593 	}
    594 
    595 	/* fill in or override the hop limit field, if necessary. */
    596 	if (opt && opt->ip6po_hlim != -1)
    597 		ip6->ip6_hlim = opt->ip6po_hlim & 0xff;
    598 	else if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
    599 		if (im6o != NULL)
    600 			ip6->ip6_hlim = im6o->im6o_multicast_hlim;
    601 		else
    602 			ip6->ip6_hlim = ip6_defmcasthlim;
    603 	}
    604 
    605 #ifdef IPSEC
    606 	if (needipsec && needipsectun) {
    607 		struct ipsec_output_state state;
    608 
    609 		/*
    610 		 * All the extension headers will become inaccessible
    611 		 * (since they can be encrypted).
    612 		 * Don't panic, we need no more updates to extension headers
    613 		 * on inner IPv6 packet (since they are now encapsulated).
    614 		 *
    615 		 * IPv6 [ESP|AH] IPv6 [extension headers] payload
    616 		 */
    617 		bzero(&exthdrs, sizeof(exthdrs));
    618 		exthdrs.ip6e_ip6 = m;
    619 
    620 		bzero(&state, sizeof(state));
    621 		state.m = m;
    622 		state.ro = ro;
    623 		state.dst = rtcache_getdst(ro);
    624 
    625 		error = ipsec6_output_tunnel(&state, sp, flags);
    626 
    627 		m = state.m;
    628 		ro_pmtu = ro = state.ro;
    629 		dst = satocsin6(state.dst);
    630 		if (error) {
    631 			/* mbuf is already reclaimed in ipsec6_output_tunnel. */
    632 			m0 = m = NULL;
    633 			m = NULL;
    634 			switch (error) {
    635 			case EHOSTUNREACH:
    636 			case ENETUNREACH:
    637 			case EMSGSIZE:
    638 			case ENOBUFS:
    639 			case ENOMEM:
    640 				break;
    641 			default:
    642 				printf("ip6_output (ipsec): error code %d\n", error);
    643 				/* FALLTHROUGH */
    644 			case ENOENT:
    645 				/* don't show these error codes to the user */
    646 				error = 0;
    647 				break;
    648 			}
    649 			goto bad;
    650 		}
    651 
    652 		exthdrs.ip6e_ip6 = m;
    653 	}
    654 #endif /* IPSEC */
    655 #ifdef FAST_IPSEC
    656 	if (needipsec) {
    657 		s = splsoftnet();
    658 		error = ipsec6_process_packet(m,sp->req);
    659 
    660 		/*
    661 		 * Preserve KAME behaviour: ENOENT can be returned
    662 		 * when an SA acquire is in progress.  Don't propagate
    663 		 * this to user-level; it confuses applications.
    664 		 * XXX this will go away when the SADB is redone.
    665 		 */
    666 		if (error == ENOENT)
    667 			error = 0;
    668 		splx(s);
    669 		goto done;
    670 	}
    671 #endif /* FAST_IPSEC */
    672 
    673 
    674 
    675 	/* adjust pointer */
    676 	ip6 = mtod(m, struct ip6_hdr *);
    677 
    678 	sockaddr_in6_init(&dst_sa, &ip6->ip6_dst, 0, 0, 0);
    679 	if ((error = in6_selectroute(&dst_sa, opt, im6o, ro,
    680 	    &ifp, &rt, 0)) != 0) {
    681 		if (ifp != NULL)
    682 			in6_ifstat_inc(ifp, ifs6_out_discard);
    683 		goto bad;
    684 	}
    685 	if (rt == NULL) {
    686 		/*
    687 		 * If in6_selectroute() does not return a route entry,
    688 		 * dst may not have been updated.
    689 		 */
    690 		rtcache_setdst(ro, sin6tosa(&dst_sa));
    691 	}
    692 
    693 	/*
    694 	 * then rt (for unicast) and ifp must be non-NULL valid values.
    695 	 */
    696 	if ((flags & IPV6_FORWARDING) == 0) {
    697 		/* XXX: the FORWARDING flag can be set for mrouting. */
    698 		in6_ifstat_inc(ifp, ifs6_out_request);
    699 	}
    700 	if (rt != NULL) {
    701 		ia = (struct in6_ifaddr *)(rt->rt_ifa);
    702 		rt->rt_use++;
    703 	}
    704 
    705 	/*
    706 	 * The outgoing interface must be in the zone of source and
    707 	 * destination addresses.  We should use ia_ifp to support the
    708 	 * case of sending packets to an address of our own.
    709 	 */
    710 	if (ia != NULL && ia->ia_ifp)
    711 		origifp = ia->ia_ifp;
    712 	else
    713 		origifp = ifp;
    714 
    715 	src0 = ip6->ip6_src;
    716 	if (in6_setscope(&src0, origifp, &zone))
    717 		goto badscope;
    718 	sockaddr_in6_init(&src_sa, &ip6->ip6_src, 0, 0, 0);
    719 	if (sa6_recoverscope(&src_sa) || zone != src_sa.sin6_scope_id)
    720 		goto badscope;
    721 
    722 	dst0 = ip6->ip6_dst;
    723 	if (in6_setscope(&dst0, origifp, &zone))
    724 		goto badscope;
    725 	/* re-initialize to be sure */
    726 	sockaddr_in6_init(&dst_sa, &ip6->ip6_dst, 0, 0, 0);
    727 	if (sa6_recoverscope(&dst_sa) || zone != dst_sa.sin6_scope_id)
    728 		goto badscope;
    729 
    730 	/* scope check is done. */
    731 
    732 	if (rt == NULL || IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
    733 		if (dst == NULL)
    734 			dst = satocsin6(rtcache_getdst(ro));
    735 		KASSERT(dst != NULL);
    736 	} else if (opt && rtcache_validate(&opt->ip6po_nextroute) != NULL) {
    737 		/*
    738 		 * The nexthop is explicitly specified by the
    739 		 * application.  We assume the next hop is an IPv6
    740 		 * address.
    741 		 */
    742 		dst = (struct sockaddr_in6 *)opt->ip6po_nexthop;
    743 	} else if ((rt->rt_flags & RTF_GATEWAY))
    744 		dst = (struct sockaddr_in6 *)rt->rt_gateway;
    745 	else if (dst == NULL)
    746 		dst = satocsin6(rtcache_getdst(ro));
    747 
    748 	/*
    749 	 * XXXXXX: original code follows:
    750 	 */
    751 	if (!IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst))
    752 		m->m_flags &= ~(M_BCAST | M_MCAST);	/* just in case */
    753 	else {
    754 		struct	in6_multi *in6m;
    755 
    756 		m->m_flags = (m->m_flags & ~M_BCAST) | M_MCAST;
    757 
    758 		in6_ifstat_inc(ifp, ifs6_out_mcast);
    759 
    760 		/*
    761 		 * Confirm that the outgoing interface supports multicast.
    762 		 */
    763 		if (!(ifp->if_flags & IFF_MULTICAST)) {
    764 			IP6_STATINC(IP6_STAT_NOROUTE);
    765 			in6_ifstat_inc(ifp, ifs6_out_discard);
    766 			error = ENETUNREACH;
    767 			goto bad;
    768 		}
    769 
    770 		IN6_LOOKUP_MULTI(ip6->ip6_dst, ifp, in6m);
    771 		if (in6m != NULL &&
    772 		   (im6o == NULL || im6o->im6o_multicast_loop)) {
    773 			/*
    774 			 * If we belong to the destination multicast group
    775 			 * on the outgoing interface, and the caller did not
    776 			 * forbid loopback, loop back a copy.
    777 			 */
    778 			KASSERT(dst != NULL);
    779 			ip6_mloopback(ifp, m, dst);
    780 		} else {
    781 			/*
    782 			 * If we are acting as a multicast router, perform
    783 			 * multicast forwarding as if the packet had just
    784 			 * arrived on the interface to which we are about
    785 			 * to send.  The multicast forwarding function
    786 			 * recursively calls this function, using the
    787 			 * IPV6_FORWARDING flag to prevent infinite recursion.
    788 			 *
    789 			 * Multicasts that are looped back by ip6_mloopback(),
    790 			 * above, will be forwarded by the ip6_input() routine,
    791 			 * if necessary.
    792 			 */
    793 			if (ip6_mrouter && (flags & IPV6_FORWARDING) == 0) {
    794 				if (ip6_mforward(ip6, ifp, m) != 0) {
    795 					m_freem(m);
    796 					goto done;
    797 				}
    798 			}
    799 		}
    800 		/*
    801 		 * Multicasts with a hoplimit of zero may be looped back,
    802 		 * above, but must not be transmitted on a network.
    803 		 * Also, multicasts addressed to the loopback interface
    804 		 * are not sent -- the above call to ip6_mloopback() will
    805 		 * loop back a copy if this host actually belongs to the
    806 		 * destination group on the loopback interface.
    807 		 */
    808 		if (ip6->ip6_hlim == 0 || (ifp->if_flags & IFF_LOOPBACK) ||
    809 		    IN6_IS_ADDR_MC_INTFACELOCAL(&ip6->ip6_dst)) {
    810 			m_freem(m);
    811 			goto done;
    812 		}
    813 	}
    814 
    815 	/*
    816 	 * Fill the outgoing inteface to tell the upper layer
    817 	 * to increment per-interface statistics.
    818 	 */
    819 	if (ifpp)
    820 		*ifpp = ifp;
    821 
    822 	/* Determine path MTU. */
    823 	if ((error = ip6_getpmtu(ro_pmtu, ro, ifp, &finaldst, &mtu,
    824 	    &alwaysfrag)) != 0)
    825 		goto bad;
    826 #ifdef IPSEC
    827 	if (needipsectun)
    828 		mtu = IPV6_MMTU;
    829 #endif
    830 
    831 	/*
    832 	 * The caller of this function may specify to use the minimum MTU
    833 	 * in some cases.
    834 	 * An advanced API option (IPV6_USE_MIN_MTU) can also override MTU
    835 	 * setting.  The logic is a bit complicated; by default, unicast
    836 	 * packets will follow path MTU while multicast packets will be sent at
    837 	 * the minimum MTU.  If IP6PO_MINMTU_ALL is specified, all packets
    838 	 * including unicast ones will be sent at the minimum MTU.  Multicast
    839 	 * packets will always be sent at the minimum MTU unless
    840 	 * IP6PO_MINMTU_DISABLE is explicitly specified.
    841 	 * See RFC 3542 for more details.
    842 	 */
    843 	if (mtu > IPV6_MMTU) {
    844 		if ((flags & IPV6_MINMTU))
    845 			mtu = IPV6_MMTU;
    846 		else if (opt && opt->ip6po_minmtu == IP6PO_MINMTU_ALL)
    847 			mtu = IPV6_MMTU;
    848 		else if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) &&
    849 			 (opt == NULL ||
    850 			  opt->ip6po_minmtu != IP6PO_MINMTU_DISABLE)) {
    851 			mtu = IPV6_MMTU;
    852 		}
    853 	}
    854 
    855 	/*
    856 	 * clear embedded scope identifiers if necessary.
    857 	 * in6_clearscope will touch the addresses only when necessary.
    858 	 */
    859 	in6_clearscope(&ip6->ip6_src);
    860 	in6_clearscope(&ip6->ip6_dst);
    861 
    862 	/*
    863 	 * If the outgoing packet contains a hop-by-hop options header,
    864 	 * it must be examined and processed even by the source node.
    865 	 * (RFC 2460, section 4.)
    866 	 */
    867 	if (exthdrs.ip6e_hbh) {
    868 		struct ip6_hbh *hbh = mtod(exthdrs.ip6e_hbh, struct ip6_hbh *);
    869 		u_int32_t dummy1; /* XXX unused */
    870 		u_int32_t dummy2; /* XXX unused */
    871 
    872 		/*
    873 		 *  XXX: if we have to send an ICMPv6 error to the sender,
    874 		 *       we need the M_LOOP flag since icmp6_error() expects
    875 		 *       the IPv6 and the hop-by-hop options header are
    876 		 *       continuous unless the flag is set.
    877 		 */
    878 		m->m_flags |= M_LOOP;
    879 		m->m_pkthdr.rcvif = ifp;
    880 		if (ip6_process_hopopts(m, (u_int8_t *)(hbh + 1),
    881 		    ((hbh->ip6h_len + 1) << 3) - sizeof(struct ip6_hbh),
    882 		    &dummy1, &dummy2) < 0) {
    883 			/* m was already freed at this point */
    884 			error = EINVAL;/* better error? */
    885 			goto done;
    886 		}
    887 		m->m_flags &= ~M_LOOP; /* XXX */
    888 		m->m_pkthdr.rcvif = NULL;
    889 	}
    890 
    891 #ifdef PFIL_HOOKS
    892 	/*
    893 	 * Run through list of hooks for output packets.
    894 	 */
    895 	if ((error = pfil_run_hooks(&inet6_pfil_hook, &m, ifp, PFIL_OUT)) != 0)
    896 		goto done;
    897 	if (m == NULL)
    898 		goto done;
    899 	ip6 = mtod(m, struct ip6_hdr *);
    900 #endif /* PFIL_HOOKS */
    901 	/*
    902 	 * Send the packet to the outgoing interface.
    903 	 * If necessary, do IPv6 fragmentation before sending.
    904 	 *
    905 	 * the logic here is rather complex:
    906 	 * 1: normal case (dontfrag == 0, alwaysfrag == 0)
    907 	 * 1-a:	send as is if tlen <= path mtu
    908 	 * 1-b:	fragment if tlen > path mtu
    909 	 *
    910 	 * 2: if user asks us not to fragment (dontfrag == 1)
    911 	 * 2-a:	send as is if tlen <= interface mtu
    912 	 * 2-b:	error if tlen > interface mtu
    913 	 *
    914 	 * 3: if we always need to attach fragment header (alwaysfrag == 1)
    915 	 *	always fragment
    916 	 *
    917 	 * 4: if dontfrag == 1 && alwaysfrag == 1
    918 	 *	error, as we cannot handle this conflicting request
    919 	 */
    920 	tlen = m->m_pkthdr.len;
    921 	tso = (m->m_pkthdr.csum_flags & M_CSUM_TSOv6) != 0;
    922 	if (opt && (opt->ip6po_flags & IP6PO_DONTFRAG))
    923 		dontfrag = 1;
    924 	else
    925 		dontfrag = 0;
    926 
    927 	if (dontfrag && alwaysfrag) {	/* case 4 */
    928 		/* conflicting request - can't transmit */
    929 		error = EMSGSIZE;
    930 		goto bad;
    931 	}
    932 	if (dontfrag && (!tso && tlen > IN6_LINKMTU(ifp))) {	/* case 2-b */
    933 		/*
    934 		 * Even if the DONTFRAG option is specified, we cannot send the
    935 		 * packet when the data length is larger than the MTU of the
    936 		 * outgoing interface.
    937 		 * Notify the error by sending IPV6_PATHMTU ancillary data as
    938 		 * well as returning an error code (the latter is not described
    939 		 * in the API spec.)
    940 		 */
    941 		u_int32_t mtu32;
    942 		struct ip6ctlparam ip6cp;
    943 
    944 		mtu32 = (u_int32_t)mtu;
    945 		bzero(&ip6cp, sizeof(ip6cp));
    946 		ip6cp.ip6c_cmdarg = (void *)&mtu32;
    947 		pfctlinput2(PRC_MSGSIZE,
    948 		    rtcache_getdst(ro_pmtu), &ip6cp);
    949 
    950 		error = EMSGSIZE;
    951 		goto bad;
    952 	}
    953 
    954 	/*
    955 	 * transmit packet without fragmentation
    956 	 */
    957 	if (dontfrag || (!alwaysfrag && (tlen <= mtu || tso))) {
    958 		/* case 1-a and 2-a */
    959 		struct in6_ifaddr *ia6;
    960 		int sw_csum;
    961 
    962 		ip6 = mtod(m, struct ip6_hdr *);
    963 		ia6 = in6_ifawithifp(ifp, &ip6->ip6_src);
    964 		if (ia6) {
    965 			/* Record statistics for this interface address. */
    966 			ia6->ia_ifa.ifa_data.ifad_outbytes += m->m_pkthdr.len;
    967 		}
    968 #ifdef IPSEC
    969 		/* clean ipsec history once it goes out of the node */
    970 		ipsec_delaux(m);
    971 #endif
    972 
    973 		sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_csum_flags_tx;
    974 		if ((sw_csum & (M_CSUM_UDPv6|M_CSUM_TCPv6)) != 0) {
    975 			if (IN6_NEED_CHECKSUM(ifp,
    976 			    sw_csum & (M_CSUM_UDPv6|M_CSUM_TCPv6))) {
    977 				in6_delayed_cksum(m);
    978 			}
    979 			m->m_pkthdr.csum_flags &= ~(M_CSUM_UDPv6|M_CSUM_TCPv6);
    980 		}
    981 
    982 		KASSERT(dst != NULL);
    983 		if (__predict_true(!tso ||
    984 		    (ifp->if_capenable & IFCAP_TSOv6) != 0)) {
    985 			error = nd6_output(ifp, origifp, m, dst, rt);
    986 		} else {
    987 			error = ip6_tso_output(ifp, origifp, m, dst, rt);
    988 		}
    989 		goto done;
    990 	}
    991 
    992 	if (tso) {
    993 		error = EINVAL; /* XXX */
    994 		goto bad;
    995 	}
    996 
    997 	/*
    998 	 * try to fragment the packet.  case 1-b and 3
    999 	 */
   1000 	if (mtu < IPV6_MMTU) {
   1001 		/* path MTU cannot be less than IPV6_MMTU */
   1002 		error = EMSGSIZE;
   1003 		in6_ifstat_inc(ifp, ifs6_out_fragfail);
   1004 		goto bad;
   1005 	} else if (ip6->ip6_plen == 0) {
   1006 		/* jumbo payload cannot be fragmented */
   1007 		error = EMSGSIZE;
   1008 		in6_ifstat_inc(ifp, ifs6_out_fragfail);
   1009 		goto bad;
   1010 	} else {
   1011 		struct mbuf **mnext, *m_frgpart;
   1012 		struct ip6_frag *ip6f;
   1013 		u_int32_t id = htonl(ip6_randomid());
   1014 		u_char nextproto;
   1015 #if 0				/* see below */
   1016 		struct ip6ctlparam ip6cp;
   1017 		u_int32_t mtu32;
   1018 #endif
   1019 
   1020 		/*
   1021 		 * Too large for the destination or interface;
   1022 		 * fragment if possible.
   1023 		 * Must be able to put at least 8 bytes per fragment.
   1024 		 */
   1025 		hlen = unfragpartlen;
   1026 		if (mtu > IPV6_MAXPACKET)
   1027 			mtu = IPV6_MAXPACKET;
   1028 
   1029 #if 0
   1030 		/*
   1031 		 * It is believed this code is a leftover from the
   1032 		 * development of the IPV6_RECVPATHMTU sockopt and
   1033 		 * associated work to implement RFC3542.
   1034 		 * It's not entirely clear what the intent of the API
   1035 		 * is at this point, so disable this code for now.
   1036 		 * The IPV6_RECVPATHMTU sockopt and/or IPV6_DONTFRAG
   1037 		 * will send notifications if the application requests.
   1038 		 */
   1039 
   1040 		/* Notify a proper path MTU to applications. */
   1041 		mtu32 = (u_int32_t)mtu;
   1042 		bzero(&ip6cp, sizeof(ip6cp));
   1043 		ip6cp.ip6c_cmdarg = (void *)&mtu32;
   1044 		pfctlinput2(PRC_MSGSIZE,
   1045 		    rtcache_getdst(ro_pmtu), &ip6cp);
   1046 #endif
   1047 
   1048 		len = (mtu - hlen - sizeof(struct ip6_frag)) & ~7;
   1049 		if (len < 8) {
   1050 			error = EMSGSIZE;
   1051 			in6_ifstat_inc(ifp, ifs6_out_fragfail);
   1052 			goto bad;
   1053 		}
   1054 
   1055 		mnext = &m->m_nextpkt;
   1056 
   1057 		/*
   1058 		 * Change the next header field of the last header in the
   1059 		 * unfragmentable part.
   1060 		 */
   1061 		if (exthdrs.ip6e_rthdr) {
   1062 			nextproto = *mtod(exthdrs.ip6e_rthdr, u_char *);
   1063 			*mtod(exthdrs.ip6e_rthdr, u_char *) = IPPROTO_FRAGMENT;
   1064 		} else if (exthdrs.ip6e_dest1) {
   1065 			nextproto = *mtod(exthdrs.ip6e_dest1, u_char *);
   1066 			*mtod(exthdrs.ip6e_dest1, u_char *) = IPPROTO_FRAGMENT;
   1067 		} else if (exthdrs.ip6e_hbh) {
   1068 			nextproto = *mtod(exthdrs.ip6e_hbh, u_char *);
   1069 			*mtod(exthdrs.ip6e_hbh, u_char *) = IPPROTO_FRAGMENT;
   1070 		} else {
   1071 			nextproto = ip6->ip6_nxt;
   1072 			ip6->ip6_nxt = IPPROTO_FRAGMENT;
   1073 		}
   1074 
   1075 		if ((m->m_pkthdr.csum_flags & (M_CSUM_UDPv6|M_CSUM_TCPv6))
   1076 		    != 0) {
   1077 			if (IN6_NEED_CHECKSUM(ifp,
   1078 			    m->m_pkthdr.csum_flags &
   1079 			    (M_CSUM_UDPv6|M_CSUM_TCPv6))) {
   1080 				in6_delayed_cksum(m);
   1081 			}
   1082 			m->m_pkthdr.csum_flags &= ~(M_CSUM_UDPv6|M_CSUM_TCPv6);
   1083 		}
   1084 
   1085 		/*
   1086 		 * Loop through length of segment after first fragment,
   1087 		 * make new header and copy data of each part and link onto
   1088 		 * chain.
   1089 		 */
   1090 		m0 = m;
   1091 		for (off = hlen; off < tlen; off += len) {
   1092 			struct mbuf *mlast;
   1093 
   1094 			MGETHDR(m, M_DONTWAIT, MT_HEADER);
   1095 			if (!m) {
   1096 				error = ENOBUFS;
   1097 				IP6_STATINC(IP6_STAT_ODROPPED);
   1098 				goto sendorfree;
   1099 			}
   1100 			m->m_pkthdr.rcvif = NULL;
   1101 			m->m_flags = m0->m_flags & M_COPYFLAGS;
   1102 			*mnext = m;
   1103 			mnext = &m->m_nextpkt;
   1104 			m->m_data += max_linkhdr;
   1105 			mhip6 = mtod(m, struct ip6_hdr *);
   1106 			*mhip6 = *ip6;
   1107 			m->m_len = sizeof(*mhip6);
   1108 			error = ip6_insertfraghdr(m0, m, hlen, &ip6f);
   1109 			if (error) {
   1110 				IP6_STATINC(IP6_STAT_ODROPPED);
   1111 				goto sendorfree;
   1112 			}
   1113 			ip6f->ip6f_offlg = htons((u_int16_t)((off - hlen) & ~7));
   1114 			if (off + len >= tlen)
   1115 				len = tlen - off;
   1116 			else
   1117 				ip6f->ip6f_offlg |= IP6F_MORE_FRAG;
   1118 			mhip6->ip6_plen = htons((u_int16_t)(len + hlen +
   1119 			    sizeof(*ip6f) - sizeof(struct ip6_hdr)));
   1120 			if ((m_frgpart = m_copy(m0, off, len)) == 0) {
   1121 				error = ENOBUFS;
   1122 				IP6_STATINC(IP6_STAT_ODROPPED);
   1123 				goto sendorfree;
   1124 			}
   1125 			for (mlast = m; mlast->m_next; mlast = mlast->m_next)
   1126 				;
   1127 			mlast->m_next = m_frgpart;
   1128 			m->m_pkthdr.len = len + hlen + sizeof(*ip6f);
   1129 			m->m_pkthdr.rcvif = (struct ifnet *)0;
   1130 			ip6f->ip6f_reserved = 0;
   1131 			ip6f->ip6f_ident = id;
   1132 			ip6f->ip6f_nxt = nextproto;
   1133 			IP6_STATINC(IP6_STAT_OFRAGMENTS);
   1134 			in6_ifstat_inc(ifp, ifs6_out_fragcreat);
   1135 		}
   1136 
   1137 		in6_ifstat_inc(ifp, ifs6_out_fragok);
   1138 	}
   1139 
   1140 	/*
   1141 	 * Remove leading garbages.
   1142 	 */
   1143 sendorfree:
   1144 	m = m0->m_nextpkt;
   1145 	m0->m_nextpkt = 0;
   1146 	m_freem(m0);
   1147 	for (m0 = m; m; m = m0) {
   1148 		m0 = m->m_nextpkt;
   1149 		m->m_nextpkt = 0;
   1150 		if (error == 0) {
   1151 			struct in6_ifaddr *ia6;
   1152 			ip6 = mtod(m, struct ip6_hdr *);
   1153 			ia6 = in6_ifawithifp(ifp, &ip6->ip6_src);
   1154 			if (ia6) {
   1155 				/*
   1156 				 * Record statistics for this interface
   1157 				 * address.
   1158 				 */
   1159 				ia6->ia_ifa.ifa_data.ifad_outbytes +=
   1160 				    m->m_pkthdr.len;
   1161 			}
   1162 #ifdef IPSEC
   1163 			/* clean ipsec history once it goes out of the node */
   1164 			ipsec_delaux(m);
   1165 #endif
   1166 			KASSERT(dst != NULL);
   1167 			error = nd6_output(ifp, origifp, m, dst, rt);
   1168 		} else
   1169 			m_freem(m);
   1170 	}
   1171 
   1172 	if (error == 0)
   1173 		IP6_STATINC(IP6_STAT_FRAGMENTED);
   1174 
   1175 done:
   1176 	rtcache_free(&ip6route);
   1177 
   1178 #ifdef IPSEC
   1179 	if (sp != NULL)
   1180 		key_freesp(sp);
   1181 #endif /* IPSEC */
   1182 #ifdef FAST_IPSEC
   1183 	if (sp != NULL)
   1184 		KEY_FREESP(&sp);
   1185 #endif /* FAST_IPSEC */
   1186 
   1187 
   1188 	return (error);
   1189 
   1190 freehdrs:
   1191 	m_freem(exthdrs.ip6e_hbh);	/* m_freem will check if mbuf is 0 */
   1192 	m_freem(exthdrs.ip6e_dest1);
   1193 	m_freem(exthdrs.ip6e_rthdr);
   1194 	m_freem(exthdrs.ip6e_dest2);
   1195 	/* FALLTHROUGH */
   1196 bad:
   1197 	m_freem(m);
   1198 	goto done;
   1199 badscope:
   1200 	IP6_STATINC(IP6_STAT_BADSCOPE);
   1201 	in6_ifstat_inc(origifp, ifs6_out_discard);
   1202 	if (error == 0)
   1203 		error = EHOSTUNREACH; /* XXX */
   1204 	goto bad;
   1205 }
   1206 
   1207 static int
   1208 ip6_copyexthdr(struct mbuf **mp, void *hdr, int hlen)
   1209 {
   1210 	struct mbuf *m;
   1211 
   1212 	if (hlen > MCLBYTES)
   1213 		return (ENOBUFS); /* XXX */
   1214 
   1215 	MGET(m, M_DONTWAIT, MT_DATA);
   1216 	if (!m)
   1217 		return (ENOBUFS);
   1218 
   1219 	if (hlen > MLEN) {
   1220 		MCLGET(m, M_DONTWAIT);
   1221 		if ((m->m_flags & M_EXT) == 0) {
   1222 			m_free(m);
   1223 			return (ENOBUFS);
   1224 		}
   1225 	}
   1226 	m->m_len = hlen;
   1227 	if (hdr)
   1228 		bcopy(hdr, mtod(m, void *), hlen);
   1229 
   1230 	*mp = m;
   1231 	return (0);
   1232 }
   1233 
   1234 /*
   1235  * Process a delayed payload checksum calculation.
   1236  */
   1237 void
   1238 in6_delayed_cksum(struct mbuf *m)
   1239 {
   1240 	uint16_t csum, offset;
   1241 
   1242 	KASSERT((m->m_pkthdr.csum_flags & (M_CSUM_UDPv6|M_CSUM_TCPv6)) != 0);
   1243 	KASSERT((~m->m_pkthdr.csum_flags & (M_CSUM_UDPv6|M_CSUM_TCPv6)) != 0);
   1244 	KASSERT((m->m_pkthdr.csum_flags
   1245 	    & (M_CSUM_UDPv4|M_CSUM_TCPv4|M_CSUM_TSOv4)) == 0);
   1246 
   1247 	offset = M_CSUM_DATA_IPv6_HL(m->m_pkthdr.csum_data);
   1248 	csum = in6_cksum(m, 0, offset, m->m_pkthdr.len - offset);
   1249 	if (csum == 0 && (m->m_pkthdr.csum_flags & M_CSUM_UDPv6) != 0) {
   1250 		csum = 0xffff;
   1251 	}
   1252 
   1253 	offset += M_CSUM_DATA_IPv6_OFFSET(m->m_pkthdr.csum_data);
   1254 	if ((offset + sizeof(csum)) > m->m_len) {
   1255 		m_copyback(m, offset, sizeof(csum), &csum);
   1256 	} else {
   1257 		*(uint16_t *)(mtod(m, char *) + offset) = csum;
   1258 	}
   1259 }
   1260 
   1261 /*
   1262  * Insert jumbo payload option.
   1263  */
   1264 static int
   1265 ip6_insert_jumboopt(struct ip6_exthdrs *exthdrs, u_int32_t plen)
   1266 {
   1267 	struct mbuf *mopt;
   1268 	u_int8_t *optbuf;
   1269 	u_int32_t v;
   1270 
   1271 #define JUMBOOPTLEN	8	/* length of jumbo payload option and padding */
   1272 
   1273 	/*
   1274 	 * If there is no hop-by-hop options header, allocate new one.
   1275 	 * If there is one but it doesn't have enough space to store the
   1276 	 * jumbo payload option, allocate a cluster to store the whole options.
   1277 	 * Otherwise, use it to store the options.
   1278 	 */
   1279 	if (exthdrs->ip6e_hbh == 0) {
   1280 		MGET(mopt, M_DONTWAIT, MT_DATA);
   1281 		if (mopt == 0)
   1282 			return (ENOBUFS);
   1283 		mopt->m_len = JUMBOOPTLEN;
   1284 		optbuf = mtod(mopt, u_int8_t *);
   1285 		optbuf[1] = 0;	/* = ((JUMBOOPTLEN) >> 3) - 1 */
   1286 		exthdrs->ip6e_hbh = mopt;
   1287 	} else {
   1288 		struct ip6_hbh *hbh;
   1289 
   1290 		mopt = exthdrs->ip6e_hbh;
   1291 		if (M_TRAILINGSPACE(mopt) < JUMBOOPTLEN) {
   1292 			/*
   1293 			 * XXX assumption:
   1294 			 * - exthdrs->ip6e_hbh is not referenced from places
   1295 			 *   other than exthdrs.
   1296 			 * - exthdrs->ip6e_hbh is not an mbuf chain.
   1297 			 */
   1298 			int oldoptlen = mopt->m_len;
   1299 			struct mbuf *n;
   1300 
   1301 			/*
   1302 			 * XXX: give up if the whole (new) hbh header does
   1303 			 * not fit even in an mbuf cluster.
   1304 			 */
   1305 			if (oldoptlen + JUMBOOPTLEN > MCLBYTES)
   1306 				return (ENOBUFS);
   1307 
   1308 			/*
   1309 			 * As a consequence, we must always prepare a cluster
   1310 			 * at this point.
   1311 			 */
   1312 			MGET(n, M_DONTWAIT, MT_DATA);
   1313 			if (n) {
   1314 				MCLGET(n, M_DONTWAIT);
   1315 				if ((n->m_flags & M_EXT) == 0) {
   1316 					m_freem(n);
   1317 					n = NULL;
   1318 				}
   1319 			}
   1320 			if (!n)
   1321 				return (ENOBUFS);
   1322 			n->m_len = oldoptlen + JUMBOOPTLEN;
   1323 			bcopy(mtod(mopt, void *), mtod(n, void *),
   1324 			    oldoptlen);
   1325 			optbuf = mtod(n, u_int8_t *) + oldoptlen;
   1326 			m_freem(mopt);
   1327 			mopt = exthdrs->ip6e_hbh = n;
   1328 		} else {
   1329 			optbuf = mtod(mopt, u_int8_t *) + mopt->m_len;
   1330 			mopt->m_len += JUMBOOPTLEN;
   1331 		}
   1332 		optbuf[0] = IP6OPT_PADN;
   1333 		optbuf[1] = 0;
   1334 
   1335 		/*
   1336 		 * Adjust the header length according to the pad and
   1337 		 * the jumbo payload option.
   1338 		 */
   1339 		hbh = mtod(mopt, struct ip6_hbh *);
   1340 		hbh->ip6h_len += (JUMBOOPTLEN >> 3);
   1341 	}
   1342 
   1343 	/* fill in the option. */
   1344 	optbuf[2] = IP6OPT_JUMBO;
   1345 	optbuf[3] = 4;
   1346 	v = (u_int32_t)htonl(plen + JUMBOOPTLEN);
   1347 	bcopy(&v, &optbuf[4], sizeof(u_int32_t));
   1348 
   1349 	/* finally, adjust the packet header length */
   1350 	exthdrs->ip6e_ip6->m_pkthdr.len += JUMBOOPTLEN;
   1351 
   1352 	return (0);
   1353 #undef JUMBOOPTLEN
   1354 }
   1355 
   1356 /*
   1357  * Insert fragment header and copy unfragmentable header portions.
   1358  */
   1359 static int
   1360 ip6_insertfraghdr(struct mbuf *m0, struct mbuf *m, int hlen,
   1361 	struct ip6_frag **frghdrp)
   1362 {
   1363 	struct mbuf *n, *mlast;
   1364 
   1365 	if (hlen > sizeof(struct ip6_hdr)) {
   1366 		n = m_copym(m0, sizeof(struct ip6_hdr),
   1367 		    hlen - sizeof(struct ip6_hdr), M_DONTWAIT);
   1368 		if (n == 0)
   1369 			return (ENOBUFS);
   1370 		m->m_next = n;
   1371 	} else
   1372 		n = m;
   1373 
   1374 	/* Search for the last mbuf of unfragmentable part. */
   1375 	for (mlast = n; mlast->m_next; mlast = mlast->m_next)
   1376 		;
   1377 
   1378 	if ((mlast->m_flags & M_EXT) == 0 &&
   1379 	    M_TRAILINGSPACE(mlast) >= sizeof(struct ip6_frag)) {
   1380 		/* use the trailing space of the last mbuf for the fragment hdr */
   1381 		*frghdrp = (struct ip6_frag *)(mtod(mlast, char *) +
   1382 		    mlast->m_len);
   1383 		mlast->m_len += sizeof(struct ip6_frag);
   1384 		m->m_pkthdr.len += sizeof(struct ip6_frag);
   1385 	} else {
   1386 		/* allocate a new mbuf for the fragment header */
   1387 		struct mbuf *mfrg;
   1388 
   1389 		MGET(mfrg, M_DONTWAIT, MT_DATA);
   1390 		if (mfrg == 0)
   1391 			return (ENOBUFS);
   1392 		mfrg->m_len = sizeof(struct ip6_frag);
   1393 		*frghdrp = mtod(mfrg, struct ip6_frag *);
   1394 		mlast->m_next = mfrg;
   1395 	}
   1396 
   1397 	return (0);
   1398 }
   1399 
   1400 static int
   1401 ip6_getpmtu(struct route *ro_pmtu, struct route *ro, struct ifnet *ifp,
   1402     const struct in6_addr *dst, u_long *mtup, int *alwaysfragp)
   1403 {
   1404 	struct rtentry *rt;
   1405 	u_int32_t mtu = 0;
   1406 	int alwaysfrag = 0;
   1407 	int error = 0;
   1408 
   1409 	if (ro_pmtu != ro) {
   1410 		union {
   1411 			struct sockaddr		dst;
   1412 			struct sockaddr_in6	dst6;
   1413 		} u;
   1414 
   1415 		/* The first hop and the final destination may differ. */
   1416 		sockaddr_in6_init(&u.dst6, dst, 0, 0, 0);
   1417 		rt = rtcache_lookup(ro_pmtu, &u.dst);
   1418 	} else
   1419 		rt = rtcache_validate(ro_pmtu);
   1420 	if (rt != NULL) {
   1421 		u_int32_t ifmtu;
   1422 
   1423 		if (ifp == NULL)
   1424 			ifp = rt->rt_ifp;
   1425 		ifmtu = IN6_LINKMTU(ifp);
   1426 		mtu = rt->rt_rmx.rmx_mtu;
   1427 		if (mtu == 0)
   1428 			mtu = ifmtu;
   1429 		else if (mtu < IPV6_MMTU) {
   1430 			/*
   1431 			 * RFC2460 section 5, last paragraph:
   1432 			 * if we record ICMPv6 too big message with
   1433 			 * mtu < IPV6_MMTU, transmit packets sized IPV6_MMTU
   1434 			 * or smaller, with fragment header attached.
   1435 			 * (fragment header is needed regardless from the
   1436 			 * packet size, for translators to identify packets)
   1437 			 */
   1438 			alwaysfrag = 1;
   1439 			mtu = IPV6_MMTU;
   1440 		} else if (mtu > ifmtu) {
   1441 			/*
   1442 			 * The MTU on the route is larger than the MTU on
   1443 			 * the interface!  This shouldn't happen, unless the
   1444 			 * MTU of the interface has been changed after the
   1445 			 * interface was brought up.  Change the MTU in the
   1446 			 * route to match the interface MTU (as long as the
   1447 			 * field isn't locked).
   1448 			 */
   1449 			mtu = ifmtu;
   1450 			if (!(rt->rt_rmx.rmx_locks & RTV_MTU))
   1451 				rt->rt_rmx.rmx_mtu = mtu;
   1452 		}
   1453 	} else if (ifp) {
   1454 		mtu = IN6_LINKMTU(ifp);
   1455 	} else
   1456 		error = EHOSTUNREACH; /* XXX */
   1457 
   1458 	*mtup = mtu;
   1459 	if (alwaysfragp)
   1460 		*alwaysfragp = alwaysfrag;
   1461 	return (error);
   1462 }
   1463 
   1464 /*
   1465  * IP6 socket option processing.
   1466  */
   1467 int
   1468 ip6_ctloutput(int op, struct socket *so, int level, int optname,
   1469     struct mbuf **mp)
   1470 {
   1471 	int privileged, optdatalen, uproto;
   1472 	void *optdata;
   1473 	struct in6pcb *in6p = sotoin6pcb(so);
   1474 	struct mbuf *m = *mp;
   1475 	int error, optval;
   1476 	int optlen;
   1477 	struct lwp *l = curlwp;	/* XXX */
   1478 
   1479 	optlen = m ? m->m_len : 0;
   1480 	error = optval = 0;
   1481 	privileged = (l == 0 || kauth_authorize_generic(l->l_cred,
   1482 	    KAUTH_GENERIC_ISSUSER, NULL)) ? 0 : 1;
   1483 	uproto = (int)so->so_proto->pr_protocol;
   1484 
   1485 	if (level != IPPROTO_IPV6) {
   1486 		if (op == PRCO_SETOPT && *mp)
   1487 			(void)m_free(*mp);
   1488 		return ENOPROTOOPT;
   1489 	}
   1490 	switch (op) {
   1491 	case PRCO_SETOPT:
   1492 		switch (optname) {
   1493 #ifdef RFC2292
   1494 		case IPV6_2292PKTOPTIONS:
   1495 			/* m is freed in ip6_pcbopts */
   1496 			error = ip6_pcbopts(&in6p->in6p_outputopts,
   1497 			    m, so);
   1498 			break;
   1499 #endif
   1500 
   1501 		/*
   1502 		 * Use of some Hop-by-Hop options or some
   1503 		 * Destination options, might require special
   1504 		 * privilege.  That is, normal applications
   1505 		 * (without special privilege) might be forbidden
   1506 		 * from setting certain options in outgoing packets,
   1507 		 * and might never see certain options in received
   1508 		 * packets. [RFC 2292 Section 6]
   1509 		 * KAME specific note:
   1510 		 *  KAME prevents non-privileged users from sending or
   1511 		 *  receiving ANY hbh/dst options in order to avoid
   1512 		 *  overhead of parsing options in the kernel.
   1513 		 */
   1514 		case IPV6_RECVHOPOPTS:
   1515 		case IPV6_RECVDSTOPTS:
   1516 		case IPV6_RECVRTHDRDSTOPTS:
   1517 			if (!privileged) {
   1518 				error = EPERM;
   1519 				break;
   1520 			}
   1521 			/* FALLTHROUGH */
   1522 		case IPV6_UNICAST_HOPS:
   1523 		case IPV6_HOPLIMIT:
   1524 		case IPV6_FAITH:
   1525 
   1526 		case IPV6_RECVPKTINFO:
   1527 		case IPV6_RECVHOPLIMIT:
   1528 		case IPV6_RECVRTHDR:
   1529 		case IPV6_RECVPATHMTU:
   1530 		case IPV6_RECVTCLASS:
   1531 		case IPV6_V6ONLY:
   1532 			if (optlen != sizeof(int)) {
   1533 				error = EINVAL;
   1534 				break;
   1535 			}
   1536 			optval = *mtod(m, int *);
   1537 			switch (optname) {
   1538 
   1539 			case IPV6_UNICAST_HOPS:
   1540 				if (optval < -1 || optval >= 256)
   1541 					error = EINVAL;
   1542 				else {
   1543 					/* -1 = kernel default */
   1544 					in6p->in6p_hops = optval;
   1545 				}
   1546 				break;
   1547 #define OPTSET(bit) \
   1548 do { \
   1549 if (optval) \
   1550 	in6p->in6p_flags |= (bit); \
   1551 else \
   1552 	in6p->in6p_flags &= ~(bit); \
   1553 } while (/*CONSTCOND*/ 0)
   1554 
   1555 #ifdef RFC2292
   1556 #define OPTSET2292(bit) 			\
   1557 do { 						\
   1558 in6p->in6p_flags |= IN6P_RFC2292; 	\
   1559 if (optval) 				\
   1560 	in6p->in6p_flags |= (bit); 	\
   1561 else 					\
   1562 	in6p->in6p_flags &= ~(bit); 	\
   1563 } while (/*CONSTCOND*/ 0)
   1564 #endif
   1565 
   1566 #define OPTBIT(bit) (in6p->in6p_flags & (bit) ? 1 : 0)
   1567 
   1568 			case IPV6_RECVPKTINFO:
   1569 #ifdef RFC2292
   1570 				/* cannot mix with RFC2292 */
   1571 				if (OPTBIT(IN6P_RFC2292)) {
   1572 					error = EINVAL;
   1573 					break;
   1574 				}
   1575 #endif
   1576 				OPTSET(IN6P_PKTINFO);
   1577 				break;
   1578 
   1579 			case IPV6_HOPLIMIT:
   1580 			{
   1581 				struct ip6_pktopts **optp;
   1582 
   1583 #ifdef RFC2292
   1584 				/* cannot mix with RFC2292 */
   1585 				if (OPTBIT(IN6P_RFC2292)) {
   1586 					error = EINVAL;
   1587 					break;
   1588 				}
   1589 #endif
   1590 				optp = &in6p->in6p_outputopts;
   1591 				error = ip6_pcbopt(IPV6_HOPLIMIT,
   1592 						   (u_char *)&optval,
   1593 						   sizeof(optval),
   1594 						   optp,
   1595 						   privileged, uproto);
   1596 				break;
   1597 			}
   1598 
   1599 			case IPV6_RECVHOPLIMIT:
   1600 #ifdef RFC2292
   1601 				/* cannot mix with RFC2292 */
   1602 				if (OPTBIT(IN6P_RFC2292)) {
   1603 					error = EINVAL;
   1604 					break;
   1605 				}
   1606 #endif
   1607 				OPTSET(IN6P_HOPLIMIT);
   1608 				break;
   1609 
   1610 			case IPV6_RECVHOPOPTS:
   1611 #ifdef RFC2292
   1612 				/* cannot mix with RFC2292 */
   1613 				if (OPTBIT(IN6P_RFC2292)) {
   1614 					error = EINVAL;
   1615 					break;
   1616 				}
   1617 #endif
   1618 				OPTSET(IN6P_HOPOPTS);
   1619 				break;
   1620 
   1621 			case IPV6_RECVDSTOPTS:
   1622 #ifdef RFC2292
   1623 				/* cannot mix with RFC2292 */
   1624 				if (OPTBIT(IN6P_RFC2292)) {
   1625 					error = EINVAL;
   1626 					break;
   1627 				}
   1628 #endif
   1629 				OPTSET(IN6P_DSTOPTS);
   1630 				break;
   1631 
   1632 			case IPV6_RECVRTHDRDSTOPTS:
   1633 #ifdef RFC2292
   1634 				/* cannot mix with RFC2292 */
   1635 				if (OPTBIT(IN6P_RFC2292)) {
   1636 					error = EINVAL;
   1637 					break;
   1638 				}
   1639 #endif
   1640 				OPTSET(IN6P_RTHDRDSTOPTS);
   1641 				break;
   1642 
   1643 			case IPV6_RECVRTHDR:
   1644 #ifdef RFC2292
   1645 				/* cannot mix with RFC2292 */
   1646 				if (OPTBIT(IN6P_RFC2292)) {
   1647 					error = EINVAL;
   1648 					break;
   1649 				}
   1650 #endif
   1651 				OPTSET(IN6P_RTHDR);
   1652 				break;
   1653 
   1654 			case IPV6_FAITH:
   1655 				OPTSET(IN6P_FAITH);
   1656 				break;
   1657 
   1658 			case IPV6_RECVPATHMTU:
   1659 				/*
   1660 				 * We ignore this option for TCP
   1661 				 * sockets.
   1662 				 * (RFC3542 leaves this case
   1663 				 * unspecified.)
   1664 				 */
   1665 				if (uproto != IPPROTO_TCP)
   1666 					OPTSET(IN6P_MTU);
   1667 				break;
   1668 
   1669 			case IPV6_V6ONLY:
   1670 				/*
   1671 				 * make setsockopt(IPV6_V6ONLY)
   1672 				 * available only prior to bind(2).
   1673 				 * see ipng mailing list, Jun 22 2001.
   1674 				 */
   1675 				if (in6p->in6p_lport ||
   1676 				    !IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_laddr)) {
   1677 					error = EINVAL;
   1678 					break;
   1679 				}
   1680 #ifdef INET6_BINDV6ONLY
   1681 				if (!optval)
   1682 					error = EINVAL;
   1683 #else
   1684 				OPTSET(IN6P_IPV6_V6ONLY);
   1685 #endif
   1686 				break;
   1687 			case IPV6_RECVTCLASS:
   1688 #ifdef RFC2292
   1689 				/* cannot mix with RFC2292 XXX */
   1690 				if (OPTBIT(IN6P_RFC2292)) {
   1691 					error = EINVAL;
   1692 					break;
   1693 				}
   1694 #endif
   1695 				OPTSET(IN6P_TCLASS);
   1696 				break;
   1697 
   1698 			}
   1699 			break;
   1700 
   1701 		case IPV6_OTCLASS:
   1702 		{
   1703 			struct ip6_pktopts **optp;
   1704 			u_int8_t tclass;
   1705 
   1706 			if (optlen != sizeof(tclass)) {
   1707 				error = EINVAL;
   1708 				break;
   1709 			}
   1710 			tclass = *mtod(m, u_int8_t *);
   1711 			optp = &in6p->in6p_outputopts;
   1712 			error = ip6_pcbopt(optname,
   1713 					   (u_char *)&tclass,
   1714 					   sizeof(tclass),
   1715 					   optp,
   1716 					   privileged, uproto);
   1717 			break;
   1718 		}
   1719 
   1720 		case IPV6_TCLASS:
   1721 		case IPV6_DONTFRAG:
   1722 		case IPV6_USE_MIN_MTU:
   1723 			if (optlen != sizeof(optval)) {
   1724 				error = EINVAL;
   1725 				break;
   1726 			}
   1727 			optval = *mtod(m, int *);
   1728 			{
   1729 				struct ip6_pktopts **optp;
   1730 				optp = &in6p->in6p_outputopts;
   1731 				error = ip6_pcbopt(optname,
   1732 						   (u_char *)&optval,
   1733 						   sizeof(optval),
   1734 						   optp,
   1735 						   privileged, uproto);
   1736 				break;
   1737 			}
   1738 
   1739 #ifdef RFC2292
   1740 		case IPV6_2292PKTINFO:
   1741 		case IPV6_2292HOPLIMIT:
   1742 		case IPV6_2292HOPOPTS:
   1743 		case IPV6_2292DSTOPTS:
   1744 		case IPV6_2292RTHDR:
   1745 			/* RFC 2292 */
   1746 			if (optlen != sizeof(int)) {
   1747 				error = EINVAL;
   1748 				break;
   1749 			}
   1750 			optval = *mtod(m, int *);
   1751 			switch (optname) {
   1752 			case IPV6_2292PKTINFO:
   1753 				OPTSET2292(IN6P_PKTINFO);
   1754 				break;
   1755 			case IPV6_2292HOPLIMIT:
   1756 				OPTSET2292(IN6P_HOPLIMIT);
   1757 				break;
   1758 			case IPV6_2292HOPOPTS:
   1759 				/*
   1760 				 * Check super-user privilege.
   1761 				 * See comments for IPV6_RECVHOPOPTS.
   1762 				 */
   1763 				if (!privileged)
   1764 					return (EPERM);
   1765 				OPTSET2292(IN6P_HOPOPTS);
   1766 				break;
   1767 			case IPV6_2292DSTOPTS:
   1768 				if (!privileged)
   1769 					return (EPERM);
   1770 				OPTSET2292(IN6P_DSTOPTS|IN6P_RTHDRDSTOPTS); /* XXX */
   1771 				break;
   1772 			case IPV6_2292RTHDR:
   1773 				OPTSET2292(IN6P_RTHDR);
   1774 				break;
   1775 			}
   1776 			break;
   1777 #endif
   1778 		case IPV6_PKTINFO:
   1779 		case IPV6_HOPOPTS:
   1780 		case IPV6_RTHDR:
   1781 		case IPV6_DSTOPTS:
   1782 		case IPV6_RTHDRDSTOPTS:
   1783 		case IPV6_NEXTHOP:
   1784 		{
   1785 			/* new advanced API (RFC3542) */
   1786 			u_char *optbuf;
   1787 			int optbuflen;
   1788 			struct ip6_pktopts **optp;
   1789 			if (!m) {
   1790 				error = EINVAL;
   1791 				break;
   1792 			}
   1793 
   1794 #ifdef RFC2292
   1795 			/* cannot mix with RFC2292 */
   1796 			if (OPTBIT(IN6P_RFC2292)) {
   1797 				error = EINVAL;
   1798 				break;
   1799 			}
   1800 #endif
   1801 
   1802 			if (m && m->m_next) {
   1803 				error = EINVAL;	/* XXX */
   1804 				break;
   1805 			}
   1806 
   1807 			optbuf = mtod(m, u_char *);
   1808 			optbuflen = m->m_len;
   1809 			optp = &in6p->in6p_outputopts;
   1810 			error = ip6_pcbopt(optname, optbuf, optbuflen,
   1811 			    optp, privileged, uproto);
   1812 			break;
   1813 		}
   1814 #undef OPTSET
   1815 
   1816 		case IPV6_MULTICAST_IF:
   1817 		case IPV6_MULTICAST_HOPS:
   1818 		case IPV6_MULTICAST_LOOP:
   1819 		case IPV6_JOIN_GROUP:
   1820 		case IPV6_LEAVE_GROUP:
   1821 			error = ip6_setmoptions(optname,
   1822 			    &in6p->in6p_moptions, m);
   1823 			break;
   1824 
   1825 		case IPV6_PORTRANGE:
   1826 			if (!m) {
   1827 				error = EINVAL;
   1828 				break;
   1829 			}
   1830 			optval = *mtod(m, int *);
   1831 
   1832 			switch (optval) {
   1833 			case IPV6_PORTRANGE_DEFAULT:
   1834 				in6p->in6p_flags &= ~(IN6P_LOWPORT);
   1835 				in6p->in6p_flags &= ~(IN6P_HIGHPORT);
   1836 				break;
   1837 
   1838 			case IPV6_PORTRANGE_HIGH:
   1839 				in6p->in6p_flags &= ~(IN6P_LOWPORT);
   1840 				in6p->in6p_flags |= IN6P_HIGHPORT;
   1841 				break;
   1842 
   1843 			case IPV6_PORTRANGE_LOW:
   1844 				in6p->in6p_flags &= ~(IN6P_HIGHPORT);
   1845 				in6p->in6p_flags |= IN6P_LOWPORT;
   1846 				break;
   1847 
   1848 			default:
   1849 				error = EINVAL;
   1850 				break;
   1851 			}
   1852 			break;
   1853 
   1854 
   1855 #if defined(IPSEC) || defined(FAST_IPSEC)
   1856 		case IPV6_IPSEC_POLICY:
   1857 		{
   1858 			void *req = NULL;
   1859 			size_t len = 0;
   1860 			if (m) {
   1861 				req = mtod(m, void *);
   1862 				len = m->m_len;
   1863 			}
   1864 			error = ipsec6_set_policy(in6p, optname, req,
   1865 						  len, privileged);
   1866 		}
   1867 			break;
   1868 #endif /* IPSEC */
   1869 
   1870 		default:
   1871 			error = ENOPROTOOPT;
   1872 			break;
   1873 		}
   1874 		if (m)
   1875 			(void)m_free(m);
   1876 		break;
   1877 
   1878 	case PRCO_GETOPT:
   1879 		switch (optname) {
   1880 #ifdef RFC2292
   1881 		case IPV6_2292PKTOPTIONS:
   1882 			/*
   1883 			 * RFC3542 (effectively) deprecated the
   1884 			 * semantics of the 2292-style pktoptions.
   1885 			 * Since it was not reliable in nature (i.e.,
   1886 			 * applications had to expect the lack of some
   1887 			 * information after all), it would make sense
   1888 			 * to simplify this part by always returning
   1889 			 * empty data.
   1890 			 */
   1891 			*mp = m_get(M_WAIT, MT_SOOPTS);
   1892 			(*mp)->m_len = 0;
   1893 			break;
   1894 #endif
   1895 
   1896 		case IPV6_RECVHOPOPTS:
   1897 		case IPV6_RECVDSTOPTS:
   1898 		case IPV6_RECVRTHDRDSTOPTS:
   1899 		case IPV6_UNICAST_HOPS:
   1900 		case IPV6_RECVPKTINFO:
   1901 		case IPV6_RECVHOPLIMIT:
   1902 		case IPV6_RECVRTHDR:
   1903 		case IPV6_RECVPATHMTU:
   1904 
   1905 		case IPV6_FAITH:
   1906 		case IPV6_V6ONLY:
   1907 		case IPV6_PORTRANGE:
   1908 		case IPV6_RECVTCLASS:
   1909 			switch (optname) {
   1910 
   1911 			case IPV6_RECVHOPOPTS:
   1912 				optval = OPTBIT(IN6P_HOPOPTS);
   1913 				break;
   1914 
   1915 			case IPV6_RECVDSTOPTS:
   1916 				optval = OPTBIT(IN6P_DSTOPTS);
   1917 				break;
   1918 
   1919 			case IPV6_RECVRTHDRDSTOPTS:
   1920 				optval = OPTBIT(IN6P_RTHDRDSTOPTS);
   1921 				break;
   1922 
   1923 			case IPV6_UNICAST_HOPS:
   1924 				optval = in6p->in6p_hops;
   1925 				break;
   1926 
   1927 			case IPV6_RECVPKTINFO:
   1928 				optval = OPTBIT(IN6P_PKTINFO);
   1929 				break;
   1930 
   1931 			case IPV6_RECVHOPLIMIT:
   1932 				optval = OPTBIT(IN6P_HOPLIMIT);
   1933 				break;
   1934 
   1935 			case IPV6_RECVRTHDR:
   1936 				optval = OPTBIT(IN6P_RTHDR);
   1937 				break;
   1938 
   1939 			case IPV6_RECVPATHMTU:
   1940 				optval = OPTBIT(IN6P_MTU);
   1941 				break;
   1942 
   1943 			case IPV6_FAITH:
   1944 				optval = OPTBIT(IN6P_FAITH);
   1945 				break;
   1946 
   1947 			case IPV6_V6ONLY:
   1948 				optval = OPTBIT(IN6P_IPV6_V6ONLY);
   1949 				break;
   1950 
   1951 			case IPV6_PORTRANGE:
   1952 			    {
   1953 				int flags;
   1954 				flags = in6p->in6p_flags;
   1955 				if (flags & IN6P_HIGHPORT)
   1956 					optval = IPV6_PORTRANGE_HIGH;
   1957 				else if (flags & IN6P_LOWPORT)
   1958 					optval = IPV6_PORTRANGE_LOW;
   1959 				else
   1960 					optval = 0;
   1961 				break;
   1962 			    }
   1963 			case IPV6_RECVTCLASS:
   1964 				optval = OPTBIT(IN6P_TCLASS);
   1965 				break;
   1966 
   1967 			}
   1968 			if (error)
   1969 				break;
   1970 			*mp = m = m_get(M_WAIT, MT_SOOPTS);
   1971 			m->m_len = sizeof(int);
   1972 			*mtod(m, int *) = optval;
   1973 			break;
   1974 
   1975 		case IPV6_PATHMTU:
   1976 		    {
   1977 			u_long pmtu = 0;
   1978 			struct ip6_mtuinfo mtuinfo;
   1979 			struct route *ro = &in6p->in6p_route;
   1980 
   1981 			if (!(so->so_state & SS_ISCONNECTED))
   1982 				return (ENOTCONN);
   1983 			/*
   1984 			 * XXX: we dot not consider the case of source
   1985 			 * routing, or optional information to specify
   1986 			 * the outgoing interface.
   1987 			 */
   1988 			error = ip6_getpmtu(ro, NULL, NULL,
   1989 			    &in6p->in6p_faddr, &pmtu, NULL);
   1990 			if (error)
   1991 				break;
   1992 			if (pmtu > IPV6_MAXPACKET)
   1993 				pmtu = IPV6_MAXPACKET;
   1994 
   1995 			memset(&mtuinfo, 0, sizeof(mtuinfo));
   1996 			mtuinfo.ip6m_mtu = (u_int32_t)pmtu;
   1997 			optdata = (void *)&mtuinfo;
   1998 			optdatalen = sizeof(mtuinfo);
   1999 			if (optdatalen > MCLBYTES)
   2000 				return (EMSGSIZE); /* XXX */
   2001 			*mp = m = m_get(M_WAIT, MT_SOOPTS);
   2002 			if (optdatalen > MLEN)
   2003 				MCLGET(m, M_WAIT);
   2004 			m->m_len = optdatalen;
   2005 			memcpy(mtod(m, void *), optdata, optdatalen);
   2006 			break;
   2007 		    }
   2008 
   2009 #ifdef RFC2292
   2010 		case IPV6_2292PKTINFO:
   2011 		case IPV6_2292HOPLIMIT:
   2012 		case IPV6_2292HOPOPTS:
   2013 		case IPV6_2292RTHDR:
   2014 		case IPV6_2292DSTOPTS:
   2015 			switch (optname) {
   2016 			case IPV6_2292PKTINFO:
   2017 				optval = OPTBIT(IN6P_PKTINFO);
   2018 				break;
   2019 			case IPV6_2292HOPLIMIT:
   2020 				optval = OPTBIT(IN6P_HOPLIMIT);
   2021 				break;
   2022 			case IPV6_2292HOPOPTS:
   2023 				optval = OPTBIT(IN6P_HOPOPTS);
   2024 				break;
   2025 			case IPV6_2292RTHDR:
   2026 				optval = OPTBIT(IN6P_RTHDR);
   2027 				break;
   2028 			case IPV6_2292DSTOPTS:
   2029 				optval = OPTBIT(IN6P_DSTOPTS|IN6P_RTHDRDSTOPTS);
   2030 				break;
   2031 			}
   2032 			*mp = m = m_get(M_WAIT, MT_SOOPTS);
   2033 			m->m_len = sizeof(int);
   2034 			*mtod(m, int *) = optval;
   2035 			break;
   2036 #endif
   2037 		case IPV6_PKTINFO:
   2038 		case IPV6_HOPOPTS:
   2039 		case IPV6_RTHDR:
   2040 		case IPV6_DSTOPTS:
   2041 		case IPV6_RTHDRDSTOPTS:
   2042 		case IPV6_NEXTHOP:
   2043 		case IPV6_OTCLASS:
   2044 		case IPV6_TCLASS:
   2045 		case IPV6_DONTFRAG:
   2046 		case IPV6_USE_MIN_MTU:
   2047 			error = ip6_getpcbopt(in6p->in6p_outputopts,
   2048 			    optname, mp);
   2049 			break;
   2050 
   2051 		case IPV6_MULTICAST_IF:
   2052 		case IPV6_MULTICAST_HOPS:
   2053 		case IPV6_MULTICAST_LOOP:
   2054 		case IPV6_JOIN_GROUP:
   2055 		case IPV6_LEAVE_GROUP:
   2056 			error = ip6_getmoptions(optname,
   2057 			    in6p->in6p_moptions, mp);
   2058 			break;
   2059 
   2060 #if defined(IPSEC) || defined(FAST_IPSEC)
   2061 		case IPV6_IPSEC_POLICY:
   2062 		    {
   2063 			void *req = NULL;
   2064 			size_t len = 0;
   2065 			if (m) {
   2066 				req = mtod(m, void *);
   2067 				len = m->m_len;
   2068 			}
   2069 			error = ipsec6_get_policy(in6p, req, len, mp);
   2070 			break;
   2071 		    }
   2072 #endif /* IPSEC */
   2073 
   2074 
   2075 
   2076 
   2077 		default:
   2078 			error = ENOPROTOOPT;
   2079 			break;
   2080 		}
   2081 		break;
   2082 	}
   2083 	return (error);
   2084 }
   2085 
   2086 int
   2087 ip6_raw_ctloutput(int op, struct socket *so, int level, int optname,
   2088 	struct mbuf **mp)
   2089 {
   2090 	int error = 0, optval, optlen;
   2091 	const int icmp6off = offsetof(struct icmp6_hdr, icmp6_cksum);
   2092 	struct in6pcb *in6p = sotoin6pcb(so);
   2093 	struct mbuf *m = *mp;
   2094 
   2095 	optlen = m ? m->m_len : 0;
   2096 
   2097 	if (level != IPPROTO_IPV6) {
   2098 		if (op == PRCO_SETOPT && *mp)
   2099 			(void)m_free(*mp);
   2100 		return ENOPROTOOPT;
   2101 	}
   2102 
   2103 	switch (optname) {
   2104 	case IPV6_CHECKSUM:
   2105 		/*
   2106 		 * For ICMPv6 sockets, no modification allowed for checksum
   2107 		 * offset, permit "no change" values to help existing apps.
   2108 		 *
   2109 		 * XXX RFC3542 says: "An attempt to set IPV6_CHECKSUM
   2110 		 * for an ICMPv6 socket will fail."  The current
   2111 		 * behavior does not meet RFC3542.
   2112 		 */
   2113 		switch (op) {
   2114 		case PRCO_SETOPT:
   2115 			if (optlen != sizeof(int)) {
   2116 				error = EINVAL;
   2117 				break;
   2118 			}
   2119 			optval = *mtod(m, int *);
   2120 			if ((optval % 2) != 0) {
   2121 				/* the API assumes even offset values */
   2122 				error = EINVAL;
   2123 			} else if (so->so_proto->pr_protocol ==
   2124 			    IPPROTO_ICMPV6) {
   2125 				if (optval != icmp6off)
   2126 					error = EINVAL;
   2127 			} else
   2128 				in6p->in6p_cksum = optval;
   2129 			break;
   2130 
   2131 		case PRCO_GETOPT:
   2132 			if (so->so_proto->pr_protocol == IPPROTO_ICMPV6)
   2133 				optval = icmp6off;
   2134 			else
   2135 				optval = in6p->in6p_cksum;
   2136 
   2137 			*mp = m = m_get(M_WAIT, MT_SOOPTS);
   2138 			m->m_len = sizeof(int);
   2139 			*mtod(m, int *) = optval;
   2140 			break;
   2141 
   2142 		default:
   2143 			error = EINVAL;
   2144 			break;
   2145 		}
   2146 		break;
   2147 
   2148 	default:
   2149 		error = ENOPROTOOPT;
   2150 		break;
   2151 	}
   2152 
   2153 	if (op == PRCO_SETOPT && m)
   2154 		(void)m_free(m);
   2155 
   2156 	return (error);
   2157 }
   2158 
   2159 #ifdef RFC2292
   2160 /*
   2161  * Set up IP6 options in pcb for insertion in output packets or
   2162  * specifying behavior of outgoing packets.
   2163  */
   2164 static int
   2165 ip6_pcbopts(struct ip6_pktopts **pktopt, struct mbuf *m, struct socket *so)
   2166 {
   2167 	struct ip6_pktopts *opt = *pktopt;
   2168 	int error = 0;
   2169 	struct lwp *l = curlwp;	/* XXX */
   2170 	int priv = 0;
   2171 
   2172 	/* turn off any old options. */
   2173 	if (opt) {
   2174 #ifdef DIAGNOSTIC
   2175 	    if (opt->ip6po_pktinfo || opt->ip6po_nexthop ||
   2176 		opt->ip6po_hbh || opt->ip6po_dest1 || opt->ip6po_dest2 ||
   2177 		opt->ip6po_rhinfo.ip6po_rhi_rthdr)
   2178 		    printf("ip6_pcbopts: all specified options are cleared.\n");
   2179 #endif
   2180 		ip6_clearpktopts(opt, -1);
   2181 	} else
   2182 		opt = malloc(sizeof(*opt), M_IP6OPT, M_WAITOK);
   2183 	*pktopt = NULL;
   2184 
   2185 	if (!m || m->m_len == 0) {
   2186 		/*
   2187 		 * Only turning off any previous options, regardless of
   2188 		 * whether the opt is just created or given.
   2189 		 */
   2190 		free(opt, M_IP6OPT);
   2191 		return (0);
   2192 	}
   2193 
   2194 	/*  set options specified by user. */
   2195 	if (l && !kauth_authorize_generic(l->l_cred, KAUTH_GENERIC_ISSUSER,
   2196 	    NULL))
   2197 		priv = 1;
   2198 	if ((error = ip6_setpktopts(m, opt, NULL, priv,
   2199 	    so->so_proto->pr_protocol)) != 0) {
   2200 		ip6_clearpktopts(opt, -1); /* XXX: discard all options */
   2201 		free(opt, M_IP6OPT);
   2202 		return (error);
   2203 	}
   2204 	*pktopt = opt;
   2205 	return (0);
   2206 }
   2207 #endif
   2208 
   2209 /*
   2210  * initialize ip6_pktopts.  beware that there are non-zero default values in
   2211  * the struct.
   2212  */
   2213 void
   2214 ip6_initpktopts(struct ip6_pktopts *opt)
   2215 {
   2216 
   2217 	memset(opt, 0, sizeof(*opt));
   2218 	opt->ip6po_hlim = -1;	/* -1 means default hop limit */
   2219 	opt->ip6po_tclass = -1;	/* -1 means default traffic class */
   2220 	opt->ip6po_minmtu = IP6PO_MINMTU_MCASTONLY;
   2221 }
   2222 
   2223 #define sin6tosa(sin6)	((struct sockaddr *)(sin6)) /* XXX */
   2224 static int
   2225 ip6_pcbopt(int optname, u_char *buf, int len, struct ip6_pktopts **pktopt,
   2226     int priv, int uproto)
   2227 {
   2228 	struct ip6_pktopts *opt;
   2229 
   2230 	if (*pktopt == NULL) {
   2231 		*pktopt = malloc(sizeof(struct ip6_pktopts), M_IP6OPT,
   2232 		    M_WAITOK);
   2233 		ip6_initpktopts(*pktopt);
   2234 	}
   2235 	opt = *pktopt;
   2236 
   2237 	return (ip6_setpktopt(optname, buf, len, opt, priv, 1, 0, uproto));
   2238 }
   2239 
   2240 static int
   2241 ip6_getpcbopt(struct ip6_pktopts *pktopt, int optname, struct mbuf **mp)
   2242 {
   2243 	void *optdata = NULL;
   2244 	int optdatalen = 0;
   2245 	struct ip6_ext *ip6e;
   2246 	int error = 0;
   2247 	struct in6_pktinfo null_pktinfo;
   2248 	int deftclass = 0, on;
   2249 	int defminmtu = IP6PO_MINMTU_MCASTONLY;
   2250 	struct mbuf *m;
   2251 
   2252 	switch (optname) {
   2253 	case IPV6_PKTINFO:
   2254 		if (pktopt && pktopt->ip6po_pktinfo)
   2255 			optdata = (void *)pktopt->ip6po_pktinfo;
   2256 		else {
   2257 			/* XXX: we don't have to do this every time... */
   2258 			memset(&null_pktinfo, 0, sizeof(null_pktinfo));
   2259 			optdata = (void *)&null_pktinfo;
   2260 		}
   2261 		optdatalen = sizeof(struct in6_pktinfo);
   2262 		break;
   2263 	case IPV6_OTCLASS:
   2264 		/* XXX */
   2265 		return (EINVAL);
   2266 	case IPV6_TCLASS:
   2267 		if (pktopt && pktopt->ip6po_tclass >= 0)
   2268 			optdata = (void *)&pktopt->ip6po_tclass;
   2269 		else
   2270 			optdata = (void *)&deftclass;
   2271 		optdatalen = sizeof(int);
   2272 		break;
   2273 	case IPV6_HOPOPTS:
   2274 		if (pktopt && pktopt->ip6po_hbh) {
   2275 			optdata = (void *)pktopt->ip6po_hbh;
   2276 			ip6e = (struct ip6_ext *)pktopt->ip6po_hbh;
   2277 			optdatalen = (ip6e->ip6e_len + 1) << 3;
   2278 		}
   2279 		break;
   2280 	case IPV6_RTHDR:
   2281 		if (pktopt && pktopt->ip6po_rthdr) {
   2282 			optdata = (void *)pktopt->ip6po_rthdr;
   2283 			ip6e = (struct ip6_ext *)pktopt->ip6po_rthdr;
   2284 			optdatalen = (ip6e->ip6e_len + 1) << 3;
   2285 		}
   2286 		break;
   2287 	case IPV6_RTHDRDSTOPTS:
   2288 		if (pktopt && pktopt->ip6po_dest1) {
   2289 			optdata = (void *)pktopt->ip6po_dest1;
   2290 			ip6e = (struct ip6_ext *)pktopt->ip6po_dest1;
   2291 			optdatalen = (ip6e->ip6e_len + 1) << 3;
   2292 		}
   2293 		break;
   2294 	case IPV6_DSTOPTS:
   2295 		if (pktopt && pktopt->ip6po_dest2) {
   2296 			optdata = (void *)pktopt->ip6po_dest2;
   2297 			ip6e = (struct ip6_ext *)pktopt->ip6po_dest2;
   2298 			optdatalen = (ip6e->ip6e_len + 1) << 3;
   2299 		}
   2300 		break;
   2301 	case IPV6_NEXTHOP:
   2302 		if (pktopt && pktopt->ip6po_nexthop) {
   2303 			optdata = (void *)pktopt->ip6po_nexthop;
   2304 			optdatalen = pktopt->ip6po_nexthop->sa_len;
   2305 		}
   2306 		break;
   2307 	case IPV6_USE_MIN_MTU:
   2308 		if (pktopt)
   2309 			optdata = (void *)&pktopt->ip6po_minmtu;
   2310 		else
   2311 			optdata = (void *)&defminmtu;
   2312 		optdatalen = sizeof(int);
   2313 		break;
   2314 	case IPV6_DONTFRAG:
   2315 		if (pktopt && ((pktopt->ip6po_flags) & IP6PO_DONTFRAG))
   2316 			on = 1;
   2317 		else
   2318 			on = 0;
   2319 		optdata = (void *)&on;
   2320 		optdatalen = sizeof(on);
   2321 		break;
   2322 	default:		/* should not happen */
   2323 #ifdef DIAGNOSTIC
   2324 		panic("ip6_getpcbopt: unexpected option\n");
   2325 #endif
   2326 		return (ENOPROTOOPT);
   2327 	}
   2328 
   2329 	if (optdatalen > MCLBYTES)
   2330 		return (EMSGSIZE); /* XXX */
   2331 	*mp = m = m_get(M_WAIT, MT_SOOPTS);
   2332 	if (optdatalen > MLEN)
   2333 		MCLGET(m, M_WAIT);
   2334 	m->m_len = optdatalen;
   2335 	if (optdatalen)
   2336 		memcpy(mtod(m, void *), optdata, optdatalen);
   2337 
   2338 	return (error);
   2339 }
   2340 
   2341 void
   2342 ip6_clearpktopts(struct ip6_pktopts *pktopt, int optname)
   2343 {
   2344 	if (optname == -1 || optname == IPV6_PKTINFO) {
   2345 		if (pktopt->ip6po_pktinfo)
   2346 			free(pktopt->ip6po_pktinfo, M_IP6OPT);
   2347 		pktopt->ip6po_pktinfo = NULL;
   2348 	}
   2349 	if (optname == -1 || optname == IPV6_HOPLIMIT)
   2350 		pktopt->ip6po_hlim = -1;
   2351 	if (optname == -1 || optname == IPV6_TCLASS)
   2352 		pktopt->ip6po_tclass = -1;
   2353 	if (optname == -1 || optname == IPV6_NEXTHOP) {
   2354 		rtcache_free(&pktopt->ip6po_nextroute);
   2355 		if (pktopt->ip6po_nexthop)
   2356 			free(pktopt->ip6po_nexthop, M_IP6OPT);
   2357 		pktopt->ip6po_nexthop = NULL;
   2358 	}
   2359 	if (optname == -1 || optname == IPV6_HOPOPTS) {
   2360 		if (pktopt->ip6po_hbh)
   2361 			free(pktopt->ip6po_hbh, M_IP6OPT);
   2362 		pktopt->ip6po_hbh = NULL;
   2363 	}
   2364 	if (optname == -1 || optname == IPV6_RTHDRDSTOPTS) {
   2365 		if (pktopt->ip6po_dest1)
   2366 			free(pktopt->ip6po_dest1, M_IP6OPT);
   2367 		pktopt->ip6po_dest1 = NULL;
   2368 	}
   2369 	if (optname == -1 || optname == IPV6_RTHDR) {
   2370 		if (pktopt->ip6po_rhinfo.ip6po_rhi_rthdr)
   2371 			free(pktopt->ip6po_rhinfo.ip6po_rhi_rthdr, M_IP6OPT);
   2372 		pktopt->ip6po_rhinfo.ip6po_rhi_rthdr = NULL;
   2373 		rtcache_free(&pktopt->ip6po_route);
   2374 	}
   2375 	if (optname == -1 || optname == IPV6_DSTOPTS) {
   2376 		if (pktopt->ip6po_dest2)
   2377 			free(pktopt->ip6po_dest2, M_IP6OPT);
   2378 		pktopt->ip6po_dest2 = NULL;
   2379 	}
   2380 }
   2381 
   2382 #define PKTOPT_EXTHDRCPY(type) 					\
   2383 do {								\
   2384 	if (src->type) {					\
   2385 		int hlen = (((struct ip6_ext *)src->type)->ip6e_len + 1) << 3;\
   2386 		dst->type = malloc(hlen, M_IP6OPT, canwait);	\
   2387 		if (dst->type == NULL && canwait == M_NOWAIT)	\
   2388 			goto bad;				\
   2389 		memcpy(dst->type, src->type, hlen);		\
   2390 	}							\
   2391 } while (/*CONSTCOND*/ 0)
   2392 
   2393 static int
   2394 copypktopts(struct ip6_pktopts *dst, struct ip6_pktopts *src, int canwait)
   2395 {
   2396 	dst->ip6po_hlim = src->ip6po_hlim;
   2397 	dst->ip6po_tclass = src->ip6po_tclass;
   2398 	dst->ip6po_flags = src->ip6po_flags;
   2399 	if (src->ip6po_pktinfo) {
   2400 		dst->ip6po_pktinfo = malloc(sizeof(*dst->ip6po_pktinfo),
   2401 		    M_IP6OPT, canwait);
   2402 		if (dst->ip6po_pktinfo == NULL && canwait == M_NOWAIT)
   2403 			goto bad;
   2404 		*dst->ip6po_pktinfo = *src->ip6po_pktinfo;
   2405 	}
   2406 	if (src->ip6po_nexthop) {
   2407 		dst->ip6po_nexthop = malloc(src->ip6po_nexthop->sa_len,
   2408 		    M_IP6OPT, canwait);
   2409 		if (dst->ip6po_nexthop == NULL && canwait == M_NOWAIT)
   2410 			goto bad;
   2411 		memcpy(dst->ip6po_nexthop, src->ip6po_nexthop,
   2412 		    src->ip6po_nexthop->sa_len);
   2413 	}
   2414 	PKTOPT_EXTHDRCPY(ip6po_hbh);
   2415 	PKTOPT_EXTHDRCPY(ip6po_dest1);
   2416 	PKTOPT_EXTHDRCPY(ip6po_dest2);
   2417 	PKTOPT_EXTHDRCPY(ip6po_rthdr); /* not copy the cached route */
   2418 	return (0);
   2419 
   2420   bad:
   2421 	if (dst->ip6po_pktinfo) free(dst->ip6po_pktinfo, M_IP6OPT);
   2422 	if (dst->ip6po_nexthop) free(dst->ip6po_nexthop, M_IP6OPT);
   2423 	if (dst->ip6po_hbh) free(dst->ip6po_hbh, M_IP6OPT);
   2424 	if (dst->ip6po_dest1) free(dst->ip6po_dest1, M_IP6OPT);
   2425 	if (dst->ip6po_dest2) free(dst->ip6po_dest2, M_IP6OPT);
   2426 	if (dst->ip6po_rthdr) free(dst->ip6po_rthdr, M_IP6OPT);
   2427 
   2428 	return (ENOBUFS);
   2429 }
   2430 #undef PKTOPT_EXTHDRCPY
   2431 
   2432 struct ip6_pktopts *
   2433 ip6_copypktopts(struct ip6_pktopts *src, int canwait)
   2434 {
   2435 	int error;
   2436 	struct ip6_pktopts *dst;
   2437 
   2438 	dst = malloc(sizeof(*dst), M_IP6OPT, canwait);
   2439 	if (dst == NULL && canwait == M_NOWAIT)
   2440 		return (NULL);
   2441 	ip6_initpktopts(dst);
   2442 
   2443 	if ((error = copypktopts(dst, src, canwait)) != 0) {
   2444 		free(dst, M_IP6OPT);
   2445 		return (NULL);
   2446 	}
   2447 
   2448 	return (dst);
   2449 }
   2450 
   2451 void
   2452 ip6_freepcbopts(struct ip6_pktopts *pktopt)
   2453 {
   2454 	if (pktopt == NULL)
   2455 		return;
   2456 
   2457 	ip6_clearpktopts(pktopt, -1);
   2458 
   2459 	free(pktopt, M_IP6OPT);
   2460 }
   2461 
   2462 /*
   2463  * Set the IP6 multicast options in response to user setsockopt().
   2464  */
   2465 static int
   2466 ip6_setmoptions(int optname, struct ip6_moptions **im6op, struct mbuf *m)
   2467 {
   2468 	int error = 0;
   2469 	u_int loop, ifindex;
   2470 	struct ipv6_mreq *mreq;
   2471 	struct ifnet *ifp;
   2472 	struct ip6_moptions *im6o = *im6op;
   2473 	struct route ro;
   2474 	struct in6_multi_mship *imm;
   2475 	struct lwp *l = curlwp;	/* XXX */
   2476 
   2477 	if (im6o == NULL) {
   2478 		/*
   2479 		 * No multicast option buffer attached to the pcb;
   2480 		 * allocate one and initialize to default values.
   2481 		 */
   2482 		im6o = (struct ip6_moptions *)
   2483 			malloc(sizeof(*im6o), M_IPMOPTS, M_WAITOK);
   2484 
   2485 		if (im6o == NULL)
   2486 			return (ENOBUFS);
   2487 		*im6op = im6o;
   2488 		im6o->im6o_multicast_ifp = NULL;
   2489 		im6o->im6o_multicast_hlim = ip6_defmcasthlim;
   2490 		im6o->im6o_multicast_loop = IPV6_DEFAULT_MULTICAST_LOOP;
   2491 		LIST_INIT(&im6o->im6o_memberships);
   2492 	}
   2493 
   2494 	switch (optname) {
   2495 
   2496 	case IPV6_MULTICAST_IF:
   2497 		/*
   2498 		 * Select the interface for outgoing multicast packets.
   2499 		 */
   2500 		if (m == NULL || m->m_len != sizeof(u_int)) {
   2501 			error = EINVAL;
   2502 			break;
   2503 		}
   2504 		bcopy(mtod(m, u_int *), &ifindex, sizeof(ifindex));
   2505 		if (ifindex != 0) {
   2506 			if (if_indexlim <= ifindex || !ifindex2ifnet[ifindex]) {
   2507 				error = ENXIO;	/* XXX EINVAL? */
   2508 				break;
   2509 			}
   2510 			ifp = ifindex2ifnet[ifindex];
   2511 			if ((ifp->if_flags & IFF_MULTICAST) == 0) {
   2512 				error = EADDRNOTAVAIL;
   2513 				break;
   2514 			}
   2515 		} else
   2516 			ifp = NULL;
   2517 		im6o->im6o_multicast_ifp = ifp;
   2518 		break;
   2519 
   2520 	case IPV6_MULTICAST_HOPS:
   2521 	    {
   2522 		/*
   2523 		 * Set the IP6 hoplimit for outgoing multicast packets.
   2524 		 */
   2525 		int optval;
   2526 		if (m == NULL || m->m_len != sizeof(int)) {
   2527 			error = EINVAL;
   2528 			break;
   2529 		}
   2530 		bcopy(mtod(m, u_int *), &optval, sizeof(optval));
   2531 		if (optval < -1 || optval >= 256)
   2532 			error = EINVAL;
   2533 		else if (optval == -1)
   2534 			im6o->im6o_multicast_hlim = ip6_defmcasthlim;
   2535 		else
   2536 			im6o->im6o_multicast_hlim = optval;
   2537 		break;
   2538 	    }
   2539 
   2540 	case IPV6_MULTICAST_LOOP:
   2541 		/*
   2542 		 * Set the loopback flag for outgoing multicast packets.
   2543 		 * Must be zero or one.
   2544 		 */
   2545 		if (m == NULL || m->m_len != sizeof(u_int)) {
   2546 			error = EINVAL;
   2547 			break;
   2548 		}
   2549 		bcopy(mtod(m, u_int *), &loop, sizeof(loop));
   2550 		if (loop > 1) {
   2551 			error = EINVAL;
   2552 			break;
   2553 		}
   2554 		im6o->im6o_multicast_loop = loop;
   2555 		break;
   2556 
   2557 	case IPV6_JOIN_GROUP:
   2558 		/*
   2559 		 * Add a multicast group membership.
   2560 		 * Group must be a valid IP6 multicast address.
   2561 		 */
   2562 		if (m == NULL || m->m_len != sizeof(struct ipv6_mreq)) {
   2563 			error = EINVAL;
   2564 			break;
   2565 		}
   2566 		mreq = mtod(m, struct ipv6_mreq *);
   2567 		if (IN6_IS_ADDR_UNSPECIFIED(&mreq->ipv6mr_multiaddr)) {
   2568 			/*
   2569 			 * We use the unspecified address to specify to accept
   2570 			 * all multicast addresses. Only super user is allowed
   2571 			 * to do this.
   2572 			 */
   2573 			if (kauth_authorize_generic(l->l_cred,
   2574 			    KAUTH_GENERIC_ISSUSER, NULL))
   2575 			{
   2576 				error = EACCES;
   2577 				break;
   2578 			}
   2579 		} else if (!IN6_IS_ADDR_MULTICAST(&mreq->ipv6mr_multiaddr)) {
   2580 			error = EINVAL;
   2581 			break;
   2582 		}
   2583 
   2584 		/*
   2585 		 * If no interface was explicitly specified, choose an
   2586 		 * appropriate one according to the given multicast address.
   2587 		 */
   2588 		if (mreq->ipv6mr_interface == 0) {
   2589 			struct rtentry *rt;
   2590 			union {
   2591 				struct sockaddr		dst;
   2592 				struct sockaddr_in6	dst6;
   2593 			} u;
   2594 
   2595 			/*
   2596 			 * Look up the routing table for the
   2597 			 * address, and choose the outgoing interface.
   2598 			 *   XXX: is it a good approach?
   2599 			 */
   2600 			memset(&ro, 0, sizeof(ro));
   2601 			sockaddr_in6_init(&u.dst6, &mreq->ipv6mr_multiaddr, 0,
   2602 			    0, 0);
   2603 			rtcache_setdst(&ro, &u.dst);
   2604 			ifp = (rt = rtcache_init(&ro)) != NULL ? rt->rt_ifp
   2605 			                                        : NULL;
   2606 			rtcache_free(&ro);
   2607 		} else {
   2608 			/*
   2609 			 * If the interface is specified, validate it.
   2610 			 */
   2611 			if (if_indexlim <= mreq->ipv6mr_interface ||
   2612 			    !ifindex2ifnet[mreq->ipv6mr_interface]) {
   2613 				error = ENXIO;	/* XXX EINVAL? */
   2614 				break;
   2615 			}
   2616 			ifp = ifindex2ifnet[mreq->ipv6mr_interface];
   2617 		}
   2618 
   2619 		/*
   2620 		 * See if we found an interface, and confirm that it
   2621 		 * supports multicast
   2622 		 */
   2623 		if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) {
   2624 			error = EADDRNOTAVAIL;
   2625 			break;
   2626 		}
   2627 
   2628 		if (in6_setscope(&mreq->ipv6mr_multiaddr, ifp, NULL)) {
   2629 			error = EADDRNOTAVAIL; /* XXX: should not happen */
   2630 			break;
   2631 		}
   2632 
   2633 		/*
   2634 		 * See if the membership already exists.
   2635 		 */
   2636 		for (imm = im6o->im6o_memberships.lh_first;
   2637 		     imm != NULL; imm = imm->i6mm_chain.le_next)
   2638 			if (imm->i6mm_maddr->in6m_ifp == ifp &&
   2639 			    IN6_ARE_ADDR_EQUAL(&imm->i6mm_maddr->in6m_addr,
   2640 			    &mreq->ipv6mr_multiaddr))
   2641 				break;
   2642 		if (imm != NULL) {
   2643 			error = EADDRINUSE;
   2644 			break;
   2645 		}
   2646 		/*
   2647 		 * Everything looks good; add a new record to the multicast
   2648 		 * address list for the given interface.
   2649 		 */
   2650 		imm = in6_joingroup(ifp, &mreq->ipv6mr_multiaddr, &error, 0);
   2651 		if (imm == NULL)
   2652 			break;
   2653 		LIST_INSERT_HEAD(&im6o->im6o_memberships, imm, i6mm_chain);
   2654 		break;
   2655 
   2656 	case IPV6_LEAVE_GROUP:
   2657 		/*
   2658 		 * Drop a multicast group membership.
   2659 		 * Group must be a valid IP6 multicast address.
   2660 		 */
   2661 		if (m == NULL || m->m_len != sizeof(struct ipv6_mreq)) {
   2662 			error = EINVAL;
   2663 			break;
   2664 		}
   2665 		mreq = mtod(m, struct ipv6_mreq *);
   2666 
   2667 		/*
   2668 		 * If an interface address was specified, get a pointer
   2669 		 * to its ifnet structure.
   2670 		 */
   2671 		if (mreq->ipv6mr_interface != 0) {
   2672 			if (if_indexlim <= mreq->ipv6mr_interface ||
   2673 			    !ifindex2ifnet[mreq->ipv6mr_interface]) {
   2674 				error = ENXIO;	/* XXX EINVAL? */
   2675 				break;
   2676 			}
   2677 			ifp = ifindex2ifnet[mreq->ipv6mr_interface];
   2678 		} else
   2679 			ifp = NULL;
   2680 
   2681 		/* Fill in the scope zone ID */
   2682 		if (ifp) {
   2683 			if (in6_setscope(&mreq->ipv6mr_multiaddr, ifp, NULL)) {
   2684 				/* XXX: should not happen */
   2685 				error = EADDRNOTAVAIL;
   2686 				break;
   2687 			}
   2688 		} else if (mreq->ipv6mr_interface != 0) {
   2689 			/*
   2690 			 * XXX: This case would happens when the (positive)
   2691 			 * index is in the valid range, but the corresponding
   2692 			 * interface has been detached dynamically.  The above
   2693 			 * check probably avoids such case to happen here, but
   2694 			 * we check it explicitly for safety.
   2695 			 */
   2696 			error = EADDRNOTAVAIL;
   2697 			break;
   2698 		} else {	/* ipv6mr_interface == 0 */
   2699 			struct sockaddr_in6 sa6_mc;
   2700 
   2701 			/*
   2702 			 * The API spec says as follows:
   2703 			 *  If the interface index is specified as 0, the
   2704 			 *  system may choose a multicast group membership to
   2705 			 *  drop by matching the multicast address only.
   2706 			 * On the other hand, we cannot disambiguate the scope
   2707 			 * zone unless an interface is provided.  Thus, we
   2708 			 * check if there's ambiguity with the default scope
   2709 			 * zone as the last resort.
   2710 			 */
   2711 			sockaddr_in6_init(&sa6_mc, &mreq->ipv6mr_multiaddr,
   2712 			    0, 0, 0);
   2713 			error = sa6_embedscope(&sa6_mc, ip6_use_defzone);
   2714 			if (error != 0)
   2715 				break;
   2716 			mreq->ipv6mr_multiaddr = sa6_mc.sin6_addr;
   2717 		}
   2718 
   2719 		/*
   2720 		 * Find the membership in the membership list.
   2721 		 */
   2722 		for (imm = im6o->im6o_memberships.lh_first;
   2723 		     imm != NULL; imm = imm->i6mm_chain.le_next) {
   2724 			if ((ifp == NULL || imm->i6mm_maddr->in6m_ifp == ifp) &&
   2725 			    IN6_ARE_ADDR_EQUAL(&imm->i6mm_maddr->in6m_addr,
   2726 			    &mreq->ipv6mr_multiaddr))
   2727 				break;
   2728 		}
   2729 		if (imm == NULL) {
   2730 			/* Unable to resolve interface */
   2731 			error = EADDRNOTAVAIL;
   2732 			break;
   2733 		}
   2734 		/*
   2735 		 * Give up the multicast address record to which the
   2736 		 * membership points.
   2737 		 */
   2738 		LIST_REMOVE(imm, i6mm_chain);
   2739 		in6_leavegroup(imm);
   2740 		break;
   2741 
   2742 	default:
   2743 		error = EOPNOTSUPP;
   2744 		break;
   2745 	}
   2746 
   2747 	/*
   2748 	 * If all options have default values, no need to keep the mbuf.
   2749 	 */
   2750 	if (im6o->im6o_multicast_ifp == NULL &&
   2751 	    im6o->im6o_multicast_hlim == ip6_defmcasthlim &&
   2752 	    im6o->im6o_multicast_loop == IPV6_DEFAULT_MULTICAST_LOOP &&
   2753 	    im6o->im6o_memberships.lh_first == NULL) {
   2754 		free(*im6op, M_IPMOPTS);
   2755 		*im6op = NULL;
   2756 	}
   2757 
   2758 	return (error);
   2759 }
   2760 
   2761 /*
   2762  * Return the IP6 multicast options in response to user getsockopt().
   2763  */
   2764 static int
   2765 ip6_getmoptions(int optname, struct ip6_moptions *im6o, struct mbuf **mp)
   2766 {
   2767 	u_int *hlim, *loop, *ifindex;
   2768 
   2769 	*mp = m_get(M_WAIT, MT_SOOPTS);
   2770 
   2771 	switch (optname) {
   2772 
   2773 	case IPV6_MULTICAST_IF:
   2774 		ifindex = mtod(*mp, u_int *);
   2775 		(*mp)->m_len = sizeof(u_int);
   2776 		if (im6o == NULL || im6o->im6o_multicast_ifp == NULL)
   2777 			*ifindex = 0;
   2778 		else
   2779 			*ifindex = im6o->im6o_multicast_ifp->if_index;
   2780 		return (0);
   2781 
   2782 	case IPV6_MULTICAST_HOPS:
   2783 		hlim = mtod(*mp, u_int *);
   2784 		(*mp)->m_len = sizeof(u_int);
   2785 		if (im6o == NULL)
   2786 			*hlim = ip6_defmcasthlim;
   2787 		else
   2788 			*hlim = im6o->im6o_multicast_hlim;
   2789 		return (0);
   2790 
   2791 	case IPV6_MULTICAST_LOOP:
   2792 		loop = mtod(*mp, u_int *);
   2793 		(*mp)->m_len = sizeof(u_int);
   2794 		if (im6o == NULL)
   2795 			*loop = ip6_defmcasthlim;
   2796 		else
   2797 			*loop = im6o->im6o_multicast_loop;
   2798 		return (0);
   2799 
   2800 	default:
   2801 		return (EOPNOTSUPP);
   2802 	}
   2803 }
   2804 
   2805 /*
   2806  * Discard the IP6 multicast options.
   2807  */
   2808 void
   2809 ip6_freemoptions(struct ip6_moptions *im6o)
   2810 {
   2811 	struct in6_multi_mship *imm;
   2812 
   2813 	if (im6o == NULL)
   2814 		return;
   2815 
   2816 	while ((imm = im6o->im6o_memberships.lh_first) != NULL) {
   2817 		LIST_REMOVE(imm, i6mm_chain);
   2818 		in6_leavegroup(imm);
   2819 	}
   2820 	free(im6o, M_IPMOPTS);
   2821 }
   2822 
   2823 /*
   2824  * Set IPv6 outgoing packet options based on advanced API.
   2825  */
   2826 int
   2827 ip6_setpktopts(struct mbuf *control, struct ip6_pktopts *opt,
   2828 	struct ip6_pktopts *stickyopt, int priv, int uproto)
   2829 {
   2830 	struct cmsghdr *cm = 0;
   2831 
   2832 	if (control == NULL || opt == NULL)
   2833 		return (EINVAL);
   2834 
   2835 	ip6_initpktopts(opt);
   2836 	if (stickyopt) {
   2837 		int error;
   2838 
   2839 		/*
   2840 		 * If stickyopt is provided, make a local copy of the options
   2841 		 * for this particular packet, then override them by ancillary
   2842 		 * objects.
   2843 		 * XXX: copypktopts() does not copy the cached route to a next
   2844 		 * hop (if any).  This is not very good in terms of efficiency,
   2845 		 * but we can allow this since this option should be rarely
   2846 		 * used.
   2847 		 */
   2848 		if ((error = copypktopts(opt, stickyopt, M_NOWAIT)) != 0)
   2849 			return (error);
   2850 	}
   2851 
   2852 	/*
   2853 	 * XXX: Currently, we assume all the optional information is stored
   2854 	 * in a single mbuf.
   2855 	 */
   2856 	if (control->m_next)
   2857 		return (EINVAL);
   2858 
   2859 	for (; control->m_len; control->m_data += CMSG_ALIGN(cm->cmsg_len),
   2860 	    control->m_len -= CMSG_ALIGN(cm->cmsg_len)) {
   2861 		int error;
   2862 
   2863 		if (control->m_len < CMSG_LEN(0))
   2864 			return (EINVAL);
   2865 
   2866 		cm = mtod(control, struct cmsghdr *);
   2867 		if (cm->cmsg_len == 0 || cm->cmsg_len > control->m_len)
   2868 			return (EINVAL);
   2869 		if (cm->cmsg_level != IPPROTO_IPV6)
   2870 			continue;
   2871 
   2872 		error = ip6_setpktopt(cm->cmsg_type, CMSG_DATA(cm),
   2873 		    cm->cmsg_len - CMSG_LEN(0), opt, priv, 0, 1, uproto);
   2874 		if (error)
   2875 			return (error);
   2876 	}
   2877 
   2878 	return (0);
   2879 }
   2880 
   2881 /*
   2882  * Set a particular packet option, as a sticky option or an ancillary data
   2883  * item.  "len" can be 0 only when it's a sticky option.
   2884  * We have 4 cases of combination of "sticky" and "cmsg":
   2885  * "sticky=0, cmsg=0": impossible
   2886  * "sticky=0, cmsg=1": RFC2292 or RFC3542 ancillary data
   2887  * "sticky=1, cmsg=0": RFC3542 socket option
   2888  * "sticky=1, cmsg=1": RFC2292 socket option
   2889  */
   2890 static int
   2891 ip6_setpktopt(int optname, u_char *buf, int len, struct ip6_pktopts *opt,
   2892     int priv, int sticky, int cmsg, int uproto)
   2893 {
   2894 	int minmtupolicy;
   2895 
   2896 	if (!sticky && !cmsg) {
   2897 #ifdef DIAGNOSTIC
   2898 		printf("ip6_setpktopt: impossible case\n");
   2899 #endif
   2900 		return (EINVAL);
   2901 	}
   2902 
   2903 	/*
   2904 	 * IPV6_2292xxx is for backward compatibility to RFC2292, and should
   2905 	 * not be specified in the context of RFC3542.  Conversely,
   2906 	 * RFC3542 types should not be specified in the context of RFC2292.
   2907 	 */
   2908 	if (!cmsg) {
   2909 		switch (optname) {
   2910 		case IPV6_2292PKTINFO:
   2911 		case IPV6_2292HOPLIMIT:
   2912 		case IPV6_2292NEXTHOP:
   2913 		case IPV6_2292HOPOPTS:
   2914 		case IPV6_2292DSTOPTS:
   2915 		case IPV6_2292RTHDR:
   2916 		case IPV6_2292PKTOPTIONS:
   2917 			return (ENOPROTOOPT);
   2918 		}
   2919 	}
   2920 	if (sticky && cmsg) {
   2921 		switch (optname) {
   2922 		case IPV6_PKTINFO:
   2923 		case IPV6_HOPLIMIT:
   2924 		case IPV6_NEXTHOP:
   2925 		case IPV6_HOPOPTS:
   2926 		case IPV6_DSTOPTS:
   2927 		case IPV6_RTHDRDSTOPTS:
   2928 		case IPV6_RTHDR:
   2929 		case IPV6_USE_MIN_MTU:
   2930 		case IPV6_DONTFRAG:
   2931 		case IPV6_OTCLASS:
   2932 		case IPV6_TCLASS:
   2933 			return (ENOPROTOOPT);
   2934 		}
   2935 	}
   2936 
   2937 	switch (optname) {
   2938 #ifdef RFC2292
   2939 	case IPV6_2292PKTINFO:
   2940 #endif
   2941 	case IPV6_PKTINFO:
   2942 	{
   2943 		struct ifnet *ifp = NULL;
   2944 		struct in6_pktinfo *pktinfo;
   2945 
   2946 		if (len != sizeof(struct in6_pktinfo))
   2947 			return (EINVAL);
   2948 
   2949 		pktinfo = (struct in6_pktinfo *)buf;
   2950 
   2951 		/*
   2952 		 * An application can clear any sticky IPV6_PKTINFO option by
   2953 		 * doing a "regular" setsockopt with ipi6_addr being
   2954 		 * in6addr_any and ipi6_ifindex being zero.
   2955 		 * [RFC 3542, Section 6]
   2956 		 */
   2957 		if (optname == IPV6_PKTINFO && opt->ip6po_pktinfo &&
   2958 		    pktinfo->ipi6_ifindex == 0 &&
   2959 		    IN6_IS_ADDR_UNSPECIFIED(&pktinfo->ipi6_addr)) {
   2960 			ip6_clearpktopts(opt, optname);
   2961 			break;
   2962 		}
   2963 
   2964 		if (uproto == IPPROTO_TCP && optname == IPV6_PKTINFO &&
   2965 		    sticky && !IN6_IS_ADDR_UNSPECIFIED(&pktinfo->ipi6_addr)) {
   2966 			return (EINVAL);
   2967 		}
   2968 
   2969 		/* validate the interface index if specified. */
   2970 		if (pktinfo->ipi6_ifindex >= if_indexlim) {
   2971 			 return (ENXIO);
   2972 		}
   2973 		if (pktinfo->ipi6_ifindex) {
   2974 			ifp = ifindex2ifnet[pktinfo->ipi6_ifindex];
   2975 			if (ifp == NULL)
   2976 				return (ENXIO);
   2977 		}
   2978 
   2979 		/*
   2980 		 * We store the address anyway, and let in6_selectsrc()
   2981 		 * validate the specified address.  This is because ipi6_addr
   2982 		 * may not have enough information about its scope zone, and
   2983 		 * we may need additional information (such as outgoing
   2984 		 * interface or the scope zone of a destination address) to
   2985 		 * disambiguate the scope.
   2986 		 * XXX: the delay of the validation may confuse the
   2987 		 * application when it is used as a sticky option.
   2988 		 */
   2989 		if (opt->ip6po_pktinfo == NULL) {
   2990 			opt->ip6po_pktinfo = malloc(sizeof(*pktinfo),
   2991 			    M_IP6OPT, M_NOWAIT);
   2992 			if (opt->ip6po_pktinfo == NULL)
   2993 				return (ENOBUFS);
   2994 		}
   2995 		memcpy(opt->ip6po_pktinfo, pktinfo, sizeof(*pktinfo));
   2996 		break;
   2997 	}
   2998 
   2999 #ifdef RFC2292
   3000 	case IPV6_2292HOPLIMIT:
   3001 #endif
   3002 	case IPV6_HOPLIMIT:
   3003 	{
   3004 		int *hlimp;
   3005 
   3006 		/*
   3007 		 * RFC 3542 deprecated the usage of sticky IPV6_HOPLIMIT
   3008 		 * to simplify the ordering among hoplimit options.
   3009 		 */
   3010 		if (optname == IPV6_HOPLIMIT && sticky)
   3011 			return (ENOPROTOOPT);
   3012 
   3013 		if (len != sizeof(int))
   3014 			return (EINVAL);
   3015 		hlimp = (int *)buf;
   3016 		if (*hlimp < -1 || *hlimp > 255)
   3017 			return (EINVAL);
   3018 
   3019 		opt->ip6po_hlim = *hlimp;
   3020 		break;
   3021 	}
   3022 
   3023 	case IPV6_OTCLASS:
   3024 		if (len != sizeof(u_int8_t))
   3025 			return (EINVAL);
   3026 
   3027 		opt->ip6po_tclass = *(u_int8_t *)buf;
   3028 		break;
   3029 
   3030 	case IPV6_TCLASS:
   3031 	{
   3032 		int tclass;
   3033 
   3034 		if (len != sizeof(int))
   3035 			return (EINVAL);
   3036 		tclass = *(int *)buf;
   3037 		if (tclass < -1 || tclass > 255)
   3038 			return (EINVAL);
   3039 
   3040 		opt->ip6po_tclass = tclass;
   3041 		break;
   3042 	}
   3043 
   3044 #ifdef RFC2292
   3045 	case IPV6_2292NEXTHOP:
   3046 #endif
   3047 	case IPV6_NEXTHOP:
   3048 		if (!priv)
   3049 			return (EPERM);
   3050 
   3051 		if (len == 0) {	/* just remove the option */
   3052 			ip6_clearpktopts(opt, IPV6_NEXTHOP);
   3053 			break;
   3054 		}
   3055 
   3056 		/* check if cmsg_len is large enough for sa_len */
   3057 		if (len < sizeof(struct sockaddr) || len < *buf)
   3058 			return (EINVAL);
   3059 
   3060 		switch (((struct sockaddr *)buf)->sa_family) {
   3061 		case AF_INET6:
   3062 		{
   3063 			struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)buf;
   3064 			int error;
   3065 
   3066 			if (sa6->sin6_len != sizeof(struct sockaddr_in6))
   3067 				return (EINVAL);
   3068 
   3069 			if (IN6_IS_ADDR_UNSPECIFIED(&sa6->sin6_addr) ||
   3070 			    IN6_IS_ADDR_MULTICAST(&sa6->sin6_addr)) {
   3071 				return (EINVAL);
   3072 			}
   3073 			if ((error = sa6_embedscope(sa6, ip6_use_defzone))
   3074 			    != 0) {
   3075 				return (error);
   3076 			}
   3077 			break;
   3078 		}
   3079 		case AF_LINK:	/* eventually be supported? */
   3080 		default:
   3081 			return (EAFNOSUPPORT);
   3082 		}
   3083 
   3084 		/* turn off the previous option, then set the new option. */
   3085 		ip6_clearpktopts(opt, IPV6_NEXTHOP);
   3086 		opt->ip6po_nexthop = malloc(*buf, M_IP6OPT, M_NOWAIT);
   3087 		if (opt->ip6po_nexthop == NULL)
   3088 			return (ENOBUFS);
   3089 		memcpy(opt->ip6po_nexthop, buf, *buf);
   3090 		break;
   3091 
   3092 #ifdef RFC2292
   3093 	case IPV6_2292HOPOPTS:
   3094 #endif
   3095 	case IPV6_HOPOPTS:
   3096 	{
   3097 		struct ip6_hbh *hbh;
   3098 		int hbhlen;
   3099 
   3100 		/*
   3101 		 * XXX: We don't allow a non-privileged user to set ANY HbH
   3102 		 * options, since per-option restriction has too much
   3103 		 * overhead.
   3104 		 */
   3105 		if (!priv)
   3106 			return (EPERM);
   3107 
   3108 		if (len == 0) {
   3109 			ip6_clearpktopts(opt, IPV6_HOPOPTS);
   3110 			break;	/* just remove the option */
   3111 		}
   3112 
   3113 		/* message length validation */
   3114 		if (len < sizeof(struct ip6_hbh))
   3115 			return (EINVAL);
   3116 		hbh = (struct ip6_hbh *)buf;
   3117 		hbhlen = (hbh->ip6h_len + 1) << 3;
   3118 		if (len != hbhlen)
   3119 			return (EINVAL);
   3120 
   3121 		/* turn off the previous option, then set the new option. */
   3122 		ip6_clearpktopts(opt, IPV6_HOPOPTS);
   3123 		opt->ip6po_hbh = malloc(hbhlen, M_IP6OPT, M_NOWAIT);
   3124 		if (opt->ip6po_hbh == NULL)
   3125 			return (ENOBUFS);
   3126 		memcpy(opt->ip6po_hbh, hbh, hbhlen);
   3127 
   3128 		break;
   3129 	}
   3130 
   3131 #ifdef RFC2292
   3132 	case IPV6_2292DSTOPTS:
   3133 #endif
   3134 	case IPV6_DSTOPTS:
   3135 	case IPV6_RTHDRDSTOPTS:
   3136 	{
   3137 		struct ip6_dest *dest, **newdest = NULL;
   3138 		int destlen;
   3139 
   3140 		if (!priv)	/* XXX: see the comment for IPV6_HOPOPTS */
   3141 			return (EPERM);
   3142 
   3143 		if (len == 0) {
   3144 			ip6_clearpktopts(opt, optname);
   3145 			break;	/* just remove the option */
   3146 		}
   3147 
   3148 		/* message length validation */
   3149 		if (len < sizeof(struct ip6_dest))
   3150 			return (EINVAL);
   3151 		dest = (struct ip6_dest *)buf;
   3152 		destlen = (dest->ip6d_len + 1) << 3;
   3153 		if (len != destlen)
   3154 			return (EINVAL);
   3155 		/*
   3156 		 * Determine the position that the destination options header
   3157 		 * should be inserted; before or after the routing header.
   3158 		 */
   3159 		switch (optname) {
   3160 		case IPV6_2292DSTOPTS:
   3161 			/*
   3162 			 * The old advanced API is ambiguous on this point.
   3163 			 * Our approach is to determine the position based
   3164 			 * according to the existence of a routing header.
   3165 			 * Note, however, that this depends on the order of the
   3166 			 * extension headers in the ancillary data; the 1st
   3167 			 * part of the destination options header must appear
   3168 			 * before the routing header in the ancillary data,
   3169 			 * too.
   3170 			 * RFC3542 solved the ambiguity by introducing
   3171 			 * separate ancillary data or option types.
   3172 			 */
   3173 			if (opt->ip6po_rthdr == NULL)
   3174 				newdest = &opt->ip6po_dest1;
   3175 			else
   3176 				newdest = &opt->ip6po_dest2;
   3177 			break;
   3178 		case IPV6_RTHDRDSTOPTS:
   3179 			newdest = &opt->ip6po_dest1;
   3180 			break;
   3181 		case IPV6_DSTOPTS:
   3182 			newdest = &opt->ip6po_dest2;
   3183 			break;
   3184 		}
   3185 
   3186 		/* turn off the previous option, then set the new option. */
   3187 		ip6_clearpktopts(opt, optname);
   3188 		*newdest = malloc(destlen, M_IP6OPT, M_NOWAIT);
   3189 		if (*newdest == NULL)
   3190 			return (ENOBUFS);
   3191 		memcpy(*newdest, dest, destlen);
   3192 
   3193 		break;
   3194 	}
   3195 
   3196 #ifdef RFC2292
   3197 	case IPV6_2292RTHDR:
   3198 #endif
   3199 	case IPV6_RTHDR:
   3200 	{
   3201 		struct ip6_rthdr *rth;
   3202 		int rthlen;
   3203 
   3204 		if (len == 0) {
   3205 			ip6_clearpktopts(opt, IPV6_RTHDR);
   3206 			break;	/* just remove the option */
   3207 		}
   3208 
   3209 		/* message length validation */
   3210 		if (len < sizeof(struct ip6_rthdr))
   3211 			return (EINVAL);
   3212 		rth = (struct ip6_rthdr *)buf;
   3213 		rthlen = (rth->ip6r_len + 1) << 3;
   3214 		if (len != rthlen)
   3215 			return (EINVAL);
   3216 		switch (rth->ip6r_type) {
   3217 		case IPV6_RTHDR_TYPE_0:
   3218 			if (rth->ip6r_len == 0)	/* must contain one addr */
   3219 				return (EINVAL);
   3220 			if (rth->ip6r_len % 2) /* length must be even */
   3221 				return (EINVAL);
   3222 			if (rth->ip6r_len / 2 != rth->ip6r_segleft)
   3223 				return (EINVAL);
   3224 			break;
   3225 		default:
   3226 			return (EINVAL);	/* not supported */
   3227 		}
   3228 		/* turn off the previous option */
   3229 		ip6_clearpktopts(opt, IPV6_RTHDR);
   3230 		opt->ip6po_rthdr = malloc(rthlen, M_IP6OPT, M_NOWAIT);
   3231 		if (opt->ip6po_rthdr == NULL)
   3232 			return (ENOBUFS);
   3233 		memcpy(opt->ip6po_rthdr, rth, rthlen);
   3234 		break;
   3235 	}
   3236 
   3237 	case IPV6_USE_MIN_MTU:
   3238 		if (len != sizeof(int))
   3239 			return (EINVAL);
   3240 		minmtupolicy = *(int *)buf;
   3241 		if (minmtupolicy != IP6PO_MINMTU_MCASTONLY &&
   3242 		    minmtupolicy != IP6PO_MINMTU_DISABLE &&
   3243 		    minmtupolicy != IP6PO_MINMTU_ALL) {
   3244 			return (EINVAL);
   3245 		}
   3246 		opt->ip6po_minmtu = minmtupolicy;
   3247 		break;
   3248 
   3249 	case IPV6_DONTFRAG:
   3250 		if (len != sizeof(int))
   3251 			return (EINVAL);
   3252 
   3253 		if (uproto == IPPROTO_TCP || *(int *)buf == 0) {
   3254 			/*
   3255 			 * we ignore this option for TCP sockets.
   3256 			 * (RFC3542 leaves this case unspecified.)
   3257 			 */
   3258 			opt->ip6po_flags &= ~IP6PO_DONTFRAG;
   3259 		} else
   3260 			opt->ip6po_flags |= IP6PO_DONTFRAG;
   3261 		break;
   3262 
   3263 	default:
   3264 		return (ENOPROTOOPT);
   3265 	} /* end of switch */
   3266 
   3267 	return (0);
   3268 }
   3269 
   3270 /*
   3271  * Routine called from ip6_output() to loop back a copy of an IP6 multicast
   3272  * packet to the input queue of a specified interface.  Note that this
   3273  * calls the output routine of the loopback "driver", but with an interface
   3274  * pointer that might NOT be lo0ifp -- easier than replicating that code here.
   3275  */
   3276 void
   3277 ip6_mloopback(struct ifnet *ifp, struct mbuf *m,
   3278 	const struct sockaddr_in6 *dst)
   3279 {
   3280 	struct mbuf *copym;
   3281 	struct ip6_hdr *ip6;
   3282 
   3283 	copym = m_copy(m, 0, M_COPYALL);
   3284 	if (copym == NULL)
   3285 		return;
   3286 
   3287 	/*
   3288 	 * Make sure to deep-copy IPv6 header portion in case the data
   3289 	 * is in an mbuf cluster, so that we can safely override the IPv6
   3290 	 * header portion later.
   3291 	 */
   3292 	if ((copym->m_flags & M_EXT) != 0 ||
   3293 	    copym->m_len < sizeof(struct ip6_hdr)) {
   3294 		copym = m_pullup(copym, sizeof(struct ip6_hdr));
   3295 		if (copym == NULL)
   3296 			return;
   3297 	}
   3298 
   3299 #ifdef DIAGNOSTIC
   3300 	if (copym->m_len < sizeof(*ip6)) {
   3301 		m_freem(copym);
   3302 		return;
   3303 	}
   3304 #endif
   3305 
   3306 	ip6 = mtod(copym, struct ip6_hdr *);
   3307 	/*
   3308 	 * clear embedded scope identifiers if necessary.
   3309 	 * in6_clearscope will touch the addresses only when necessary.
   3310 	 */
   3311 	in6_clearscope(&ip6->ip6_src);
   3312 	in6_clearscope(&ip6->ip6_dst);
   3313 
   3314 	(void)looutput(ifp, copym, (const struct sockaddr *)dst, NULL);
   3315 }
   3316 
   3317 /*
   3318  * Chop IPv6 header off from the payload.
   3319  */
   3320 static int
   3321 ip6_splithdr(struct mbuf *m,  struct ip6_exthdrs *exthdrs)
   3322 {
   3323 	struct mbuf *mh;
   3324 	struct ip6_hdr *ip6;
   3325 
   3326 	ip6 = mtod(m, struct ip6_hdr *);
   3327 	if (m->m_len > sizeof(*ip6)) {
   3328 		MGETHDR(mh, M_DONTWAIT, MT_HEADER);
   3329 		if (mh == 0) {
   3330 			m_freem(m);
   3331 			return ENOBUFS;
   3332 		}
   3333 		M_MOVE_PKTHDR(mh, m);
   3334 		MH_ALIGN(mh, sizeof(*ip6));
   3335 		m->m_len -= sizeof(*ip6);
   3336 		m->m_data += sizeof(*ip6);
   3337 		mh->m_next = m;
   3338 		m = mh;
   3339 		m->m_len = sizeof(*ip6);
   3340 		bcopy((void *)ip6, mtod(m, void *), sizeof(*ip6));
   3341 	}
   3342 	exthdrs->ip6e_ip6 = m;
   3343 	return 0;
   3344 }
   3345 
   3346 /*
   3347  * Compute IPv6 extension header length.
   3348  */
   3349 int
   3350 ip6_optlen(struct in6pcb *in6p)
   3351 {
   3352 	int len;
   3353 
   3354 	if (!in6p->in6p_outputopts)
   3355 		return 0;
   3356 
   3357 	len = 0;
   3358 #define elen(x) \
   3359     (((struct ip6_ext *)(x)) ? (((struct ip6_ext *)(x))->ip6e_len + 1) << 3 : 0)
   3360 
   3361 	len += elen(in6p->in6p_outputopts->ip6po_hbh);
   3362 	len += elen(in6p->in6p_outputopts->ip6po_dest1);
   3363 	len += elen(in6p->in6p_outputopts->ip6po_rthdr);
   3364 	len += elen(in6p->in6p_outputopts->ip6po_dest2);
   3365 	return len;
   3366 #undef elen
   3367 }
   3368