Home | History | Annotate | Line # | Download | only in netinet6
ip6_output.c revision 1.117.2.1
      1 /*	$NetBSD: ip6_output.c,v 1.117.2.1 2007/06/08 14:17:55 ad 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 1.117.2.1 2007/06/08 14:17:55 ad 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/in6_pcb.h>
     97 #include <netinet6/nd6.h>
     98 #include <netinet6/ip6protosw.h>
     99 #include <netinet6/scope6_var.h>
    100 
    101 #ifdef IPSEC
    102 #include <netinet6/ipsec.h>
    103 #include <netkey/key.h>
    104 #endif /* IPSEC */
    105 
    106 #ifdef FAST_IPSEC
    107 #include <netipsec/ipsec.h>
    108 #include <netipsec/ipsec6.h>
    109 #include <netipsec/key.h>
    110 #include <netipsec/xform.h>
    111 #endif
    112 
    113 
    114 #include <net/net_osdep.h>
    115 
    116 #ifdef PFIL_HOOKS
    117 extern struct pfil_head inet6_pfil_hook;	/* XXX */
    118 #endif
    119 
    120 struct ip6_exthdrs {
    121 	struct mbuf *ip6e_ip6;
    122 	struct mbuf *ip6e_hbh;
    123 	struct mbuf *ip6e_dest1;
    124 	struct mbuf *ip6e_rthdr;
    125 	struct mbuf *ip6e_dest2;
    126 };
    127 
    128 static int ip6_pcbopt __P((int, u_char *, int, struct ip6_pktopts **,
    129 	int, int));
    130 static int ip6_getpcbopt __P((struct ip6_pktopts *, int, struct mbuf **));
    131 static int ip6_setpktopt __P((int, u_char *, int, struct ip6_pktopts *, int,
    132 	int, int, int));
    133 static int ip6_setmoptions __P((int, struct ip6_moptions **, struct mbuf *));
    134 static int ip6_getmoptions __P((int, struct ip6_moptions *, struct mbuf **));
    135 static int ip6_copyexthdr __P((struct mbuf **, void *, int));
    136 static int ip6_insertfraghdr __P((struct mbuf *, struct mbuf *, int,
    137 	struct ip6_frag **));
    138 static int ip6_insert_jumboopt __P((struct ip6_exthdrs *, u_int32_t));
    139 static int ip6_splithdr __P((struct mbuf *, struct ip6_exthdrs *));
    140 static int ip6_getpmtu(struct route *, struct route *, struct ifnet *,
    141     const struct in6_addr *, u_long *, int *);
    142 static int copypktopts __P((struct ip6_pktopts *, struct ip6_pktopts *, int));
    143 
    144 #ifdef RFC2292
    145 static int ip6_pcbopts __P((struct ip6_pktopts **, struct mbuf *,
    146 	struct socket *));
    147 #endif
    148 
    149 #define	IN6_NEED_CHECKSUM(ifp, csum_flags) \
    150 	(__predict_true(((ifp)->if_flags & IFF_LOOPBACK) == 0 || \
    151 	(((csum_flags) & M_CSUM_UDPv6) != 0 && udp_do_loopback_cksum) || \
    152 	(((csum_flags) & M_CSUM_TCPv6) != 0 && tcp_do_loopback_cksum)))
    153 
    154 /*
    155  * IP6 output. The packet in mbuf chain m contains a skeletal IP6
    156  * header (with pri, len, nxt, hlim, src, dst).
    157  * This function may modify ver and hlim only.
    158  * The mbuf chain containing the packet will be freed.
    159  * The mbuf opt, if present, will not be freed.
    160  *
    161  * type of "mtu": rt_rmx.rmx_mtu is u_long, ifnet.ifr_mtu is int, and
    162  * nd_ifinfo.linkmtu is u_int32_t.  so we use u_long to hold largest one,
    163  * which is rt_rmx.rmx_mtu.
    164  */
    165 int
    166 ip6_output(
    167     struct mbuf *m0,
    168     struct ip6_pktopts *opt,
    169     struct route *ro,
    170     int flags,
    171     struct ip6_moptions *im6o,
    172     struct socket *so,
    173     struct ifnet **ifpp		/* XXX: just for statistics */
    174 )
    175 {
    176 	struct ip6_hdr *ip6, *mhip6;
    177 	struct ifnet *ifp, *origifp;
    178 	struct mbuf *m = m0;
    179 	int hlen, tlen, len, off;
    180 	bool tso;
    181 	struct route ip6route;
    182 	struct rtentry *rt = NULL;
    183 	const struct sockaddr_in6 *dst = NULL;
    184 	struct sockaddr_in6 src_sa, dst_sa;
    185 	int error = 0;
    186 	struct in6_ifaddr *ia = NULL;
    187 	u_long mtu;
    188 	int alwaysfrag, dontfrag;
    189 	u_int32_t optlen = 0, plen = 0, unfragpartlen = 0;
    190 	struct ip6_exthdrs exthdrs;
    191 	struct in6_addr finaldst, src0, dst0;
    192 	u_int32_t zone;
    193 	struct route *ro_pmtu = NULL;
    194 	int hdrsplit = 0;
    195 	int needipsec = 0;
    196 #ifdef IPSEC
    197 	int needipsectun = 0;
    198 	struct secpolicy *sp = NULL;
    199 
    200 	ip6 = mtod(m, struct ip6_hdr *);
    201 #endif /* IPSEC */
    202 #ifdef FAST_IPSEC
    203 	struct secpolicy *sp = NULL;
    204 	int s;
    205 #endif
    206 
    207 
    208 #ifdef  DIAGNOSTIC
    209 	if ((m->m_flags & M_PKTHDR) == 0)
    210 		panic("ip6_output: no HDR");
    211 
    212 	if ((m->m_pkthdr.csum_flags &
    213 	    (M_CSUM_TCPv4|M_CSUM_UDPv4|M_CSUM_TSOv4)) != 0) {
    214 		panic("ip6_output: IPv4 checksum offload flags: %d",
    215 		    m->m_pkthdr.csum_flags);
    216 	}
    217 
    218 	if ((m->m_pkthdr.csum_flags & (M_CSUM_TCPv6|M_CSUM_UDPv6)) ==
    219 	    (M_CSUM_TCPv6|M_CSUM_UDPv6)) {
    220 		panic("ip6_output: conflicting checksum offload flags: %d",
    221 		    m->m_pkthdr.csum_flags);
    222 	}
    223 #endif
    224 
    225 	M_CSUM_DATA_IPv6_HL_SET(m->m_pkthdr.csum_data, sizeof(struct ip6_hdr));
    226 
    227 #define MAKE_EXTHDR(hp, mp)						\
    228     do {								\
    229 	if (hp) {							\
    230 		struct ip6_ext *eh = (struct ip6_ext *)(hp);		\
    231 		error = ip6_copyexthdr((mp), (void *)(hp), 		\
    232 		    ((eh)->ip6e_len + 1) << 3);				\
    233 		if (error)						\
    234 			goto freehdrs;					\
    235 	}								\
    236     } while (/*CONSTCOND*/ 0)
    237 
    238 	bzero(&exthdrs, sizeof(exthdrs));
    239 	if (opt) {
    240 		/* Hop-by-Hop options header */
    241 		MAKE_EXTHDR(opt->ip6po_hbh, &exthdrs.ip6e_hbh);
    242 		/* Destination options header(1st part) */
    243 		MAKE_EXTHDR(opt->ip6po_dest1, &exthdrs.ip6e_dest1);
    244 		/* Routing header */
    245 		MAKE_EXTHDR(opt->ip6po_rthdr, &exthdrs.ip6e_rthdr);
    246 		/* Destination options header(2nd part) */
    247 		MAKE_EXTHDR(opt->ip6po_dest2, &exthdrs.ip6e_dest2);
    248 	}
    249 
    250 #ifdef IPSEC
    251 	if ((flags & IPV6_FORWARDING) != 0) {
    252 		needipsec = 0;
    253 		goto skippolicycheck;
    254 	}
    255 
    256 	/* get a security policy for this packet */
    257 	if (so == NULL)
    258 		sp = ipsec6_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, 0, &error);
    259 	else {
    260 		if (IPSEC_PCB_SKIP_IPSEC(sotoinpcb_hdr(so)->inph_sp,
    261 					 IPSEC_DIR_OUTBOUND)) {
    262 			needipsec = 0;
    263 			goto skippolicycheck;
    264 		}
    265 		sp = ipsec6_getpolicybysock(m, IPSEC_DIR_OUTBOUND, so, &error);
    266 	}
    267 
    268 	if (sp == NULL) {
    269 		ipsec6stat.out_inval++;
    270 		goto freehdrs;
    271 	}
    272 
    273 	error = 0;
    274 
    275 	/* check policy */
    276 	switch (sp->policy) {
    277 	case IPSEC_POLICY_DISCARD:
    278 		/*
    279 		 * This packet is just discarded.
    280 		 */
    281 		ipsec6stat.out_polvio++;
    282 		goto freehdrs;
    283 
    284 	case IPSEC_POLICY_BYPASS:
    285 	case IPSEC_POLICY_NONE:
    286 		/* no need to do IPsec. */
    287 		needipsec = 0;
    288 		break;
    289 
    290 	case IPSEC_POLICY_IPSEC:
    291 		if (sp->req == NULL) {
    292 			/* XXX should be panic ? */
    293 			printf("ip6_output: No IPsec request specified.\n");
    294 			error = EINVAL;
    295 			goto freehdrs;
    296 		}
    297 		needipsec = 1;
    298 		break;
    299 
    300 	case IPSEC_POLICY_ENTRUST:
    301 	default:
    302 		printf("ip6_output: Invalid policy found. %d\n", sp->policy);
    303 	}
    304 
    305   skippolicycheck:;
    306 #endif /* IPSEC */
    307 
    308 	/*
    309 	 * Calculate the total length of the extension header chain.
    310 	 * Keep the length of the unfragmentable part for fragmentation.
    311 	 */
    312 	optlen = 0;
    313 	if (exthdrs.ip6e_hbh) optlen += exthdrs.ip6e_hbh->m_len;
    314 	if (exthdrs.ip6e_dest1) optlen += exthdrs.ip6e_dest1->m_len;
    315 	if (exthdrs.ip6e_rthdr) optlen += exthdrs.ip6e_rthdr->m_len;
    316 	unfragpartlen = optlen + sizeof(struct ip6_hdr);
    317 	/* NOTE: we don't add AH/ESP length here. do that later. */
    318 	if (exthdrs.ip6e_dest2) optlen += exthdrs.ip6e_dest2->m_len;
    319 
    320 #ifdef FAST_IPSEC
    321 	/* Check the security policy (SP) for the packet */
    322 
    323 	/* XXX For moment, we doesn't support packet with extented action */
    324 	if (optlen !=0)
    325 		goto freehdrs;
    326 
    327 	sp = ipsec6_check_policy(m,so,flags,&needipsec,&error);
    328 	if (error != 0) {
    329 		/*
    330 		 * Hack: -EINVAL is used to signal that a packet
    331 		 * should be silently discarded.  This is typically
    332 		 * because we asked key management for an SA and
    333 		 * it was delayed (e.g. kicked up to IKE).
    334 		 */
    335 	if (error == -EINVAL)
    336 		error = 0;
    337 	goto freehdrs;
    338     }
    339 #endif /* FAST_IPSEC */
    340 
    341 
    342 	if (needipsec &&
    343 	    (m->m_pkthdr.csum_flags & (M_CSUM_UDPv6|M_CSUM_TCPv6)) != 0) {
    344 		in6_delayed_cksum(m);
    345 		m->m_pkthdr.csum_flags &= ~(M_CSUM_UDPv6|M_CSUM_TCPv6);
    346 	}
    347 
    348 
    349 	/*
    350 	 * If we need IPsec, or there is at least one extension header,
    351 	 * separate IP6 header from the payload.
    352 	 */
    353 	if ((needipsec || optlen) && !hdrsplit) {
    354 		if ((error = ip6_splithdr(m, &exthdrs)) != 0) {
    355 			m = NULL;
    356 			goto freehdrs;
    357 		}
    358 		m = exthdrs.ip6e_ip6;
    359 		hdrsplit++;
    360 	}
    361 
    362 	/* adjust pointer */
    363 	ip6 = mtod(m, struct ip6_hdr *);
    364 
    365 	/* adjust mbuf packet header length */
    366 	m->m_pkthdr.len += optlen;
    367 	plen = m->m_pkthdr.len - sizeof(*ip6);
    368 
    369 	/* If this is a jumbo payload, insert a jumbo payload option. */
    370 	if (plen > IPV6_MAXPACKET) {
    371 		if (!hdrsplit) {
    372 			if ((error = ip6_splithdr(m, &exthdrs)) != 0) {
    373 				m = NULL;
    374 				goto freehdrs;
    375 			}
    376 			m = exthdrs.ip6e_ip6;
    377 			hdrsplit++;
    378 		}
    379 		/* adjust pointer */
    380 		ip6 = mtod(m, struct ip6_hdr *);
    381 		if ((error = ip6_insert_jumboopt(&exthdrs, plen)) != 0)
    382 			goto freehdrs;
    383 		optlen += 8; /* XXX JUMBOOPTLEN */
    384 		ip6->ip6_plen = 0;
    385 	} else
    386 		ip6->ip6_plen = htons(plen);
    387 
    388 	/*
    389 	 * Concatenate headers and fill in next header fields.
    390 	 * Here we have, on "m"
    391 	 *	IPv6 payload
    392 	 * and we insert headers accordingly.  Finally, we should be getting:
    393 	 *	IPv6 hbh dest1 rthdr ah* [esp* dest2 payload]
    394 	 *
    395 	 * during the header composing process, "m" points to IPv6 header.
    396 	 * "mprev" points to an extension header prior to esp.
    397 	 */
    398 	{
    399 		u_char *nexthdrp = &ip6->ip6_nxt;
    400 		struct mbuf *mprev = m;
    401 
    402 		/*
    403 		 * we treat dest2 specially.  this makes IPsec processing
    404 		 * much easier.  the goal here is to make mprev point the
    405 		 * mbuf prior to dest2.
    406 		 *
    407 		 * result: IPv6 dest2 payload
    408 		 * m and mprev will point to IPv6 header.
    409 		 */
    410 		if (exthdrs.ip6e_dest2) {
    411 			if (!hdrsplit)
    412 				panic("assumption failed: hdr not split");
    413 			exthdrs.ip6e_dest2->m_next = m->m_next;
    414 			m->m_next = exthdrs.ip6e_dest2;
    415 			*mtod(exthdrs.ip6e_dest2, u_char *) = ip6->ip6_nxt;
    416 			ip6->ip6_nxt = IPPROTO_DSTOPTS;
    417 		}
    418 
    419 #define MAKE_CHAIN(m, mp, p, i)\
    420     do {\
    421 	if (m) {\
    422 		if (!hdrsplit) \
    423 			panic("assumption failed: hdr not split"); \
    424 		*mtod((m), u_char *) = *(p);\
    425 		*(p) = (i);\
    426 		p = mtod((m), u_char *);\
    427 		(m)->m_next = (mp)->m_next;\
    428 		(mp)->m_next = (m);\
    429 		(mp) = (m);\
    430 	}\
    431     } while (/*CONSTCOND*/ 0)
    432 		/*
    433 		 * result: IPv6 hbh dest1 rthdr dest2 payload
    434 		 * m will point to IPv6 header.  mprev will point to the
    435 		 * extension header prior to dest2 (rthdr in the above case).
    436 		 */
    437 		MAKE_CHAIN(exthdrs.ip6e_hbh, mprev, nexthdrp, IPPROTO_HOPOPTS);
    438 		MAKE_CHAIN(exthdrs.ip6e_dest1, mprev, nexthdrp,
    439 		    IPPROTO_DSTOPTS);
    440 		MAKE_CHAIN(exthdrs.ip6e_rthdr, mprev, nexthdrp,
    441 		    IPPROTO_ROUTING);
    442 
    443 		M_CSUM_DATA_IPv6_HL_SET(m->m_pkthdr.csum_data,
    444 		    sizeof(struct ip6_hdr) + optlen);
    445 
    446 #ifdef IPSEC
    447 		if (!needipsec)
    448 			goto skip_ipsec2;
    449 
    450 		/*
    451 		 * pointers after IPsec headers are not valid any more.
    452 		 * other pointers need a great care too.
    453 		 * (IPsec routines should not mangle mbufs prior to AH/ESP)
    454 		 */
    455 		exthdrs.ip6e_dest2 = NULL;
    456 
    457 	    {
    458 		struct ip6_rthdr *rh = NULL;
    459 		int segleft_org = 0;
    460 		struct ipsec_output_state state;
    461 
    462 		if (exthdrs.ip6e_rthdr) {
    463 			rh = mtod(exthdrs.ip6e_rthdr, struct ip6_rthdr *);
    464 			segleft_org = rh->ip6r_segleft;
    465 			rh->ip6r_segleft = 0;
    466 		}
    467 
    468 		bzero(&state, sizeof(state));
    469 		state.m = m;
    470 		error = ipsec6_output_trans(&state, nexthdrp, mprev, sp, flags,
    471 		    &needipsectun);
    472 		m = state.m;
    473 		if (error) {
    474 			rh = mtod(exthdrs.ip6e_rthdr, struct ip6_rthdr *);
    475 			/* mbuf is already reclaimed in ipsec6_output_trans. */
    476 			m = NULL;
    477 			switch (error) {
    478 			case EHOSTUNREACH:
    479 			case ENETUNREACH:
    480 			case EMSGSIZE:
    481 			case ENOBUFS:
    482 			case ENOMEM:
    483 				break;
    484 			default:
    485 				printf("ip6_output (ipsec): error code %d\n", error);
    486 				/* FALLTHROUGH */
    487 			case ENOENT:
    488 				/* don't show these error codes to the user */
    489 				error = 0;
    490 				break;
    491 			}
    492 			goto bad;
    493 		}
    494 		if (exthdrs.ip6e_rthdr) {
    495 			/* ah6_output doesn't modify mbuf chain */
    496 			rh->ip6r_segleft = segleft_org;
    497 		}
    498 	    }
    499 skip_ipsec2:;
    500 #endif
    501 	}
    502 
    503 	/*
    504 	 * If there is a routing header, replace destination address field
    505 	 * with the first hop of the routing header.
    506 	 */
    507 	if (exthdrs.ip6e_rthdr) {
    508 		struct ip6_rthdr *rh;
    509 		struct ip6_rthdr0 *rh0;
    510 		struct in6_addr *addr;
    511 		struct sockaddr_in6 sa;
    512 
    513 		rh = (struct ip6_rthdr *)(mtod(exthdrs.ip6e_rthdr,
    514 		    struct ip6_rthdr *));
    515 		finaldst = ip6->ip6_dst;
    516 		switch (rh->ip6r_type) {
    517 		case IPV6_RTHDR_TYPE_0:
    518 			 rh0 = (struct ip6_rthdr0 *)rh;
    519 			 addr = (struct in6_addr *)(rh0 + 1);
    520 
    521 			 /*
    522 			  * construct a sockaddr_in6 form of
    523 			  * the first hop.
    524 			  *
    525 			  * XXX: we may not have enough
    526 			  * information about its scope zone;
    527 			  * there is no standard API to pass
    528 			  * the information from the
    529 			  * application.
    530 			  */
    531 			 bzero(&sa, sizeof(sa));
    532 			 sa.sin6_family = AF_INET6;
    533 			 sa.sin6_len = sizeof(sa);
    534 			 sa.sin6_addr = addr[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 		ip6stat.ip6s_badscope++;
    558 		goto bad;
    559 	}
    560 	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_src)) {
    561 		error = EOPNOTSUPP;
    562 		ip6stat.ip6s_badscope++;
    563 		goto bad;
    564 	}
    565 
    566 	ip6stat.ip6s_localout++;
    567 
    568 	/*
    569 	 * Route packet.
    570 	 */
    571 	/* initialize cached route */
    572 	if (ro == NULL) {
    573 		memset(&ip6route, 0, sizeof(ip6route));
    574 		ro = &ip6route;
    575 	}
    576 	ro_pmtu = ro;
    577 	if (opt && opt->ip6po_rthdr)
    578 		ro = &opt->ip6po_route;
    579 
    580  	/*
    581 	 * if specified, try to fill in the traffic class field.
    582 	 * do not override if a non-zero value is already set.
    583 	 * we check the diffserv field and the ecn field separately.
    584 	 */
    585 	if (opt && opt->ip6po_tclass >= 0) {
    586 		int mask = 0;
    587 
    588 		if ((ip6->ip6_flow & htonl(0xfc << 20)) == 0)
    589 			mask |= 0xfc;
    590 		if ((ip6->ip6_flow & htonl(0x03 << 20)) == 0)
    591 			mask |= 0x03;
    592 		if (mask != 0)
    593 			ip6->ip6_flow |= htonl((opt->ip6po_tclass & mask) << 20);
    594 	}
    595 
    596 	/* fill in or override the hop limit field, if necessary. */
    597 	if (opt && opt->ip6po_hlim != -1)
    598 		ip6->ip6_hlim = opt->ip6po_hlim & 0xff;
    599 	else if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
    600 		if (im6o != NULL)
    601 			ip6->ip6_hlim = im6o->im6o_multicast_hlim;
    602 		else
    603 			ip6->ip6_hlim = ip6_defmcasthlim;
    604 	}
    605 
    606 #ifdef IPSEC
    607 	if (needipsec && needipsectun) {
    608 		struct ipsec_output_state state;
    609 
    610 		/*
    611 		 * All the extension headers will become inaccessible
    612 		 * (since they can be encrypted).
    613 		 * Don't panic, we need no more updates to extension headers
    614 		 * on inner IPv6 packet (since they are now encapsulated).
    615 		 *
    616 		 * IPv6 [ESP|AH] IPv6 [extension headers] payload
    617 		 */
    618 		bzero(&exthdrs, sizeof(exthdrs));
    619 		exthdrs.ip6e_ip6 = m;
    620 
    621 		bzero(&state, sizeof(state));
    622 		state.m = m;
    623 		state.ro = ro;
    624 		state.dst = rtcache_getdst(ro);
    625 
    626 		error = ipsec6_output_tunnel(&state, sp, flags);
    627 
    628 		m = state.m;
    629 		ro_pmtu = ro = state.ro;
    630 		dst = satocsin6(state.dst);
    631 		if (error) {
    632 			/* mbuf is already reclaimed in ipsec6_output_tunnel. */
    633 			m0 = m = NULL;
    634 			m = NULL;
    635 			switch (error) {
    636 			case EHOSTUNREACH:
    637 			case ENETUNREACH:
    638 			case EMSGSIZE:
    639 			case ENOBUFS:
    640 			case ENOMEM:
    641 				break;
    642 			default:
    643 				printf("ip6_output (ipsec): error code %d\n", error);
    644 				/* FALLTHROUGH */
    645 			case ENOENT:
    646 				/* don't show these error codes to the user */
    647 				error = 0;
    648 				break;
    649 			}
    650 			goto bad;
    651 		}
    652 
    653 		exthdrs.ip6e_ip6 = m;
    654 	}
    655 #endif /* IPSEC */
    656 #ifdef FAST_IPSEC
    657 	if (needipsec) {
    658 		s = splsoftnet();
    659 		error = ipsec6_process_packet(m,sp->req);
    660 
    661 		/*
    662 		 * Preserve KAME behaviour: ENOENT can be returned
    663 		 * when an SA acquire is in progress.  Don't propagate
    664 		 * this to user-level; it confuses applications.
    665 		 * XXX this will go away when the SADB is redone.
    666 		 */
    667 		if (error == ENOENT)
    668 			error = 0;
    669 		splx(s);
    670 		goto done;
    671 	}
    672 #endif /* FAST_IPSEC */
    673 
    674 
    675 
    676 	/* adjust pointer */
    677 	ip6 = mtod(m, struct ip6_hdr *);
    678 
    679 	bzero(&dst_sa, sizeof(dst_sa));
    680 	dst_sa.sin6_family = AF_INET6;
    681 	dst_sa.sin6_len = sizeof(dst_sa);
    682 	dst_sa.sin6_addr = ip6->ip6_dst;
    683 	if ((error = in6_selectroute(&dst_sa, opt, im6o, ro,
    684 	    &ifp, &rt, 0)) != 0) {
    685 		switch (error) {
    686 		case EHOSTUNREACH:
    687 			ip6stat.ip6s_noroute++;
    688 			break;
    689 		case EADDRNOTAVAIL:
    690 		default:
    691 			break; /* XXX statistics? */
    692 		}
    693 		if (ifp != NULL)
    694 			in6_ifstat_inc(ifp, ifs6_out_discard);
    695 		goto bad;
    696 	}
    697 	if (rt == NULL) {
    698 		/*
    699 		 * If in6_selectroute() does not return a route entry,
    700 		 * dst may not have been updated.
    701 		 */
    702 		rtcache_setdst(ro, sin6tosa(&dst_sa));
    703 	}
    704 
    705 	/*
    706 	 * then rt (for unicast) and ifp must be non-NULL valid values.
    707 	 */
    708 	if ((flags & IPV6_FORWARDING) == 0) {
    709 		/* XXX: the FORWARDING flag can be set for mrouting. */
    710 		in6_ifstat_inc(ifp, ifs6_out_request);
    711 	}
    712 	if (rt != NULL) {
    713 		ia = (struct in6_ifaddr *)(rt->rt_ifa);
    714 		rt->rt_use++;
    715 	}
    716 
    717 	/*
    718 	 * The outgoing interface must be in the zone of source and
    719 	 * destination addresses.  We should use ia_ifp to support the
    720 	 * case of sending packets to an address of our own.
    721 	 */
    722 	if (ia != NULL && ia->ia_ifp)
    723 		origifp = ia->ia_ifp;
    724 	else
    725 		origifp = ifp;
    726 
    727 	src0 = ip6->ip6_src;
    728 	if (in6_setscope(&src0, origifp, &zone))
    729 		goto badscope;
    730 	bzero(&src_sa, sizeof(src_sa));
    731 	src_sa.sin6_family = AF_INET6;
    732 	src_sa.sin6_len = sizeof(src_sa);
    733 	src_sa.sin6_addr = ip6->ip6_src;
    734 	if (sa6_recoverscope(&src_sa) || zone != src_sa.sin6_scope_id)
    735 		goto badscope;
    736 
    737 	dst0 = ip6->ip6_dst;
    738 	if (in6_setscope(&dst0, origifp, &zone))
    739 		goto badscope;
    740 	/* re-initialize to be sure */
    741 	bzero(&dst_sa, sizeof(dst_sa));
    742 	dst_sa.sin6_family = AF_INET6;
    743 	dst_sa.sin6_len = sizeof(dst_sa);
    744 	dst_sa.sin6_addr = ip6->ip6_dst;
    745 	if (sa6_recoverscope(&dst_sa) || zone != dst_sa.sin6_scope_id)
    746 		goto badscope;
    747 
    748 	/* scope check is done. */
    749 
    750 	if (rt == NULL || IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
    751 		if (dst == NULL)
    752 			dst = satocsin6(rtcache_getdst(ro));
    753 		KASSERT(dst != NULL);
    754 	} else if (opt && opt->ip6po_nextroute.ro_rt != NULL) {
    755 		/*
    756 		 * The nexthop is explicitly specified by the
    757 		 * application.  We assume the next hop is an IPv6
    758 		 * address.
    759 		 */
    760 		dst = (struct sockaddr_in6 *)opt->ip6po_nexthop;
    761 	} else if ((rt->rt_flags & RTF_GATEWAY))
    762 		dst = (struct sockaddr_in6 *)rt->rt_gateway;
    763 	else if (dst == NULL)
    764 		dst = satocsin6(rtcache_getdst(ro));
    765 
    766 	/*
    767 	 * XXXXXX: original code follows:
    768 	 */
    769 	if (!IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst))
    770 		m->m_flags &= ~(M_BCAST | M_MCAST);	/* just in case */
    771 	else {
    772 		struct	in6_multi *in6m;
    773 
    774 		m->m_flags = (m->m_flags & ~M_BCAST) | M_MCAST;
    775 
    776 		in6_ifstat_inc(ifp, ifs6_out_mcast);
    777 
    778 		/*
    779 		 * Confirm that the outgoing interface supports multicast.
    780 		 */
    781 		if (!(ifp->if_flags & IFF_MULTICAST)) {
    782 			ip6stat.ip6s_noroute++;
    783 			in6_ifstat_inc(ifp, ifs6_out_discard);
    784 			error = ENETUNREACH;
    785 			goto bad;
    786 		}
    787 
    788 		IN6_LOOKUP_MULTI(ip6->ip6_dst, ifp, in6m);
    789 		if (in6m != NULL &&
    790 		   (im6o == NULL || im6o->im6o_multicast_loop)) {
    791 			/*
    792 			 * If we belong to the destination multicast group
    793 			 * on the outgoing interface, and the caller did not
    794 			 * forbid loopback, loop back a copy.
    795 			 */
    796 			KASSERT(dst != NULL);
    797 			ip6_mloopback(ifp, m, dst);
    798 		} else {
    799 			/*
    800 			 * If we are acting as a multicast router, perform
    801 			 * multicast forwarding as if the packet had just
    802 			 * arrived on the interface to which we are about
    803 			 * to send.  The multicast forwarding function
    804 			 * recursively calls this function, using the
    805 			 * IPV6_FORWARDING flag to prevent infinite recursion.
    806 			 *
    807 			 * Multicasts that are looped back by ip6_mloopback(),
    808 			 * above, will be forwarded by the ip6_input() routine,
    809 			 * if necessary.
    810 			 */
    811 			if (ip6_mrouter && (flags & IPV6_FORWARDING) == 0) {
    812 				if (ip6_mforward(ip6, ifp, m) != 0) {
    813 					m_freem(m);
    814 					goto done;
    815 				}
    816 			}
    817 		}
    818 		/*
    819 		 * Multicasts with a hoplimit of zero may be looped back,
    820 		 * above, but must not be transmitted on a network.
    821 		 * Also, multicasts addressed to the loopback interface
    822 		 * are not sent -- the above call to ip6_mloopback() will
    823 		 * loop back a copy if this host actually belongs to the
    824 		 * destination group on the loopback interface.
    825 		 */
    826 		if (ip6->ip6_hlim == 0 || (ifp->if_flags & IFF_LOOPBACK) ||
    827 		    IN6_IS_ADDR_MC_INTFACELOCAL(&ip6->ip6_dst)) {
    828 			m_freem(m);
    829 			goto done;
    830 		}
    831 	}
    832 
    833 	/*
    834 	 * Fill the outgoing inteface to tell the upper layer
    835 	 * to increment per-interface statistics.
    836 	 */
    837 	if (ifpp)
    838 		*ifpp = ifp;
    839 
    840 	/* Determine path MTU. */
    841 	if ((error = ip6_getpmtu(ro_pmtu, ro, ifp, &finaldst, &mtu,
    842 	    &alwaysfrag)) != 0)
    843 		goto bad;
    844 #ifdef IPSEC
    845 	if (needipsectun)
    846 		mtu = IPV6_MMTU;
    847 #endif
    848 
    849 	/*
    850 	 * The caller of this function may specify to use the minimum MTU
    851 	 * in some cases.
    852 	 * An advanced API option (IPV6_USE_MIN_MTU) can also override MTU
    853 	 * setting.  The logic is a bit complicated; by default, unicast
    854 	 * packets will follow path MTU while multicast packets will be sent at
    855 	 * the minimum MTU.  If IP6PO_MINMTU_ALL is specified, all packets
    856 	 * including unicast ones will be sent at the minimum MTU.  Multicast
    857 	 * packets will always be sent at the minimum MTU unless
    858 	 * IP6PO_MINMTU_DISABLE is explicitly specified.
    859 	 * See RFC 3542 for more details.
    860 	 */
    861 	if (mtu > IPV6_MMTU) {
    862 		if ((flags & IPV6_MINMTU))
    863 			mtu = IPV6_MMTU;
    864 		else if (opt && opt->ip6po_minmtu == IP6PO_MINMTU_ALL)
    865 			mtu = IPV6_MMTU;
    866 		else if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) &&
    867 			 (opt == NULL ||
    868 			  opt->ip6po_minmtu != IP6PO_MINMTU_DISABLE)) {
    869 			mtu = IPV6_MMTU;
    870 		}
    871 	}
    872 
    873 	/*
    874 	 * clear embedded scope identifiers if necessary.
    875 	 * in6_clearscope will touch the addresses only when necessary.
    876 	 */
    877 	in6_clearscope(&ip6->ip6_src);
    878 	in6_clearscope(&ip6->ip6_dst);
    879 
    880 	/*
    881 	 * If the outgoing packet contains a hop-by-hop options header,
    882 	 * it must be examined and processed even by the source node.
    883 	 * (RFC 2460, section 4.)
    884 	 */
    885 	if (exthdrs.ip6e_hbh) {
    886 		struct ip6_hbh *hbh = mtod(exthdrs.ip6e_hbh, struct ip6_hbh *);
    887 		u_int32_t dummy1; /* XXX unused */
    888 		u_int32_t dummy2; /* XXX unused */
    889 
    890 		/*
    891 		 *  XXX: if we have to send an ICMPv6 error to the sender,
    892 		 *       we need the M_LOOP flag since icmp6_error() expects
    893 		 *       the IPv6 and the hop-by-hop options header are
    894 		 *       continuous unless the flag is set.
    895 		 */
    896 		m->m_flags |= M_LOOP;
    897 		m->m_pkthdr.rcvif = ifp;
    898 		if (ip6_process_hopopts(m, (u_int8_t *)(hbh + 1),
    899 		    ((hbh->ip6h_len + 1) << 3) - sizeof(struct ip6_hbh),
    900 		    &dummy1, &dummy2) < 0) {
    901 			/* m was already freed at this point */
    902 			error = EINVAL;/* better error? */
    903 			goto done;
    904 		}
    905 		m->m_flags &= ~M_LOOP; /* XXX */
    906 		m->m_pkthdr.rcvif = NULL;
    907 	}
    908 
    909 #ifdef PFIL_HOOKS
    910 	/*
    911 	 * Run through list of hooks for output packets.
    912 	 */
    913 	if ((error = pfil_run_hooks(&inet6_pfil_hook, &m, ifp, PFIL_OUT)) != 0)
    914 		goto done;
    915 	if (m == NULL)
    916 		goto done;
    917 	ip6 = mtod(m, struct ip6_hdr *);
    918 #endif /* PFIL_HOOKS */
    919 	/*
    920 	 * Send the packet to the outgoing interface.
    921 	 * If necessary, do IPv6 fragmentation before sending.
    922 	 *
    923 	 * the logic here is rather complex:
    924 	 * 1: normal case (dontfrag == 0, alwaysfrag == 0)
    925 	 * 1-a:	send as is if tlen <= path mtu
    926 	 * 1-b:	fragment if tlen > path mtu
    927 	 *
    928 	 * 2: if user asks us not to fragment (dontfrag == 1)
    929 	 * 2-a:	send as is if tlen <= interface mtu
    930 	 * 2-b:	error if tlen > interface mtu
    931 	 *
    932 	 * 3: if we always need to attach fragment header (alwaysfrag == 1)
    933 	 *	always fragment
    934 	 *
    935 	 * 4: if dontfrag == 1 && alwaysfrag == 1
    936 	 *	error, as we cannot handle this conflicting request
    937 	 */
    938 	tlen = m->m_pkthdr.len;
    939 	tso = (m->m_pkthdr.csum_flags & M_CSUM_TSOv6) != 0;
    940 	if (opt && (opt->ip6po_flags & IP6PO_DONTFRAG))
    941 		dontfrag = 1;
    942 	else
    943 		dontfrag = 0;
    944 
    945 	if (dontfrag && alwaysfrag) {	/* case 4 */
    946 		/* conflicting request - can't transmit */
    947 		error = EMSGSIZE;
    948 		goto bad;
    949 	}
    950 	if (dontfrag && (!tso && tlen > IN6_LINKMTU(ifp))) {	/* case 2-b */
    951 		/*
    952 		 * Even if the DONTFRAG option is specified, we cannot send the
    953 		 * packet when the data length is larger than the MTU of the
    954 		 * outgoing interface.
    955 		 * Notify the error by sending IPV6_PATHMTU ancillary data as
    956 		 * well as returning an error code (the latter is not described
    957 		 * in the API spec.)
    958 		 */
    959 		u_int32_t mtu32;
    960 		struct ip6ctlparam ip6cp;
    961 
    962 		mtu32 = (u_int32_t)mtu;
    963 		bzero(&ip6cp, sizeof(ip6cp));
    964 		ip6cp.ip6c_cmdarg = (void *)&mtu32;
    965 		pfctlinput2(PRC_MSGSIZE,
    966 		    rtcache_getdst(ro_pmtu), &ip6cp);
    967 
    968 		error = EMSGSIZE;
    969 		goto bad;
    970 	}
    971 
    972 	/*
    973 	 * transmit packet without fragmentation
    974 	 */
    975 	if (dontfrag || (!alwaysfrag && (tlen <= mtu || tso))) {
    976 		/* case 1-a and 2-a */
    977 		struct in6_ifaddr *ia6;
    978 		int sw_csum;
    979 
    980 		ip6 = mtod(m, struct ip6_hdr *);
    981 		ia6 = in6_ifawithifp(ifp, &ip6->ip6_src);
    982 		if (ia6) {
    983 			/* Record statistics for this interface address. */
    984 			ia6->ia_ifa.ifa_data.ifad_outbytes += m->m_pkthdr.len;
    985 		}
    986 #ifdef IPSEC
    987 		/* clean ipsec history once it goes out of the node */
    988 		ipsec_delaux(m);
    989 #endif
    990 
    991 		sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_csum_flags_tx;
    992 		if ((sw_csum & (M_CSUM_UDPv6|M_CSUM_TCPv6)) != 0) {
    993 			if (IN6_NEED_CHECKSUM(ifp,
    994 			    sw_csum & (M_CSUM_UDPv6|M_CSUM_TCPv6))) {
    995 				in6_delayed_cksum(m);
    996 			}
    997 			m->m_pkthdr.csum_flags &= ~(M_CSUM_UDPv6|M_CSUM_TCPv6);
    998 		}
    999 
   1000 		KASSERT(dst != NULL);
   1001 		if (__predict_true(!tso ||
   1002 		    (ifp->if_capenable & IFCAP_TSOv6) != 0)) {
   1003 			error = nd6_output(ifp, origifp, m, dst, rt);
   1004 		} else {
   1005 			error = ip6_tso_output(ifp, origifp, m, dst, rt);
   1006 		}
   1007 		goto done;
   1008 	}
   1009 
   1010 	if (tso) {
   1011 		error = EINVAL; /* XXX */
   1012 		goto bad;
   1013 	}
   1014 
   1015 	/*
   1016 	 * try to fragment the packet.  case 1-b and 3
   1017 	 */
   1018 	if (mtu < IPV6_MMTU) {
   1019 		/* path MTU cannot be less than IPV6_MMTU */
   1020 		error = EMSGSIZE;
   1021 		in6_ifstat_inc(ifp, ifs6_out_fragfail);
   1022 		goto bad;
   1023 	} else if (ip6->ip6_plen == 0) {
   1024 		/* jumbo payload cannot be fragmented */
   1025 		error = EMSGSIZE;
   1026 		in6_ifstat_inc(ifp, ifs6_out_fragfail);
   1027 		goto bad;
   1028 	} else {
   1029 		struct mbuf **mnext, *m_frgpart;
   1030 		struct ip6_frag *ip6f;
   1031 		u_int32_t id = htonl(ip6_randomid());
   1032 		u_char nextproto;
   1033 #if 0				/* see below */
   1034 		struct ip6ctlparam ip6cp;
   1035 		u_int32_t mtu32;
   1036 #endif
   1037 
   1038 		/*
   1039 		 * Too large for the destination or interface;
   1040 		 * fragment if possible.
   1041 		 * Must be able to put at least 8 bytes per fragment.
   1042 		 */
   1043 		hlen = unfragpartlen;
   1044 		if (mtu > IPV6_MAXPACKET)
   1045 			mtu = IPV6_MAXPACKET;
   1046 
   1047 #if 0
   1048 		/*
   1049 		 * It is believed this code is a leftover from the
   1050 		 * development of the IPV6_RECVPATHMTU sockopt and
   1051 		 * associated work to implement RFC3542.
   1052 		 * It's not entirely clear what the intent of the API
   1053 		 * is at this point, so disable this code for now.
   1054 		 * The IPV6_RECVPATHMTU sockopt and/or IPV6_DONTFRAG
   1055 		 * will send notifications if the application requests.
   1056 		 */
   1057 
   1058 		/* Notify a proper path MTU to applications. */
   1059 		mtu32 = (u_int32_t)mtu;
   1060 		bzero(&ip6cp, sizeof(ip6cp));
   1061 		ip6cp.ip6c_cmdarg = (void *)&mtu32;
   1062 		pfctlinput2(PRC_MSGSIZE,
   1063 		    rtcache_getdst(ro_pmtu), &ip6cp);
   1064 #endif
   1065 
   1066 		len = (mtu - hlen - sizeof(struct ip6_frag)) & ~7;
   1067 		if (len < 8) {
   1068 			error = EMSGSIZE;
   1069 			in6_ifstat_inc(ifp, ifs6_out_fragfail);
   1070 			goto bad;
   1071 		}
   1072 
   1073 		mnext = &m->m_nextpkt;
   1074 
   1075 		/*
   1076 		 * Change the next header field of the last header in the
   1077 		 * unfragmentable part.
   1078 		 */
   1079 		if (exthdrs.ip6e_rthdr) {
   1080 			nextproto = *mtod(exthdrs.ip6e_rthdr, u_char *);
   1081 			*mtod(exthdrs.ip6e_rthdr, u_char *) = IPPROTO_FRAGMENT;
   1082 		} else if (exthdrs.ip6e_dest1) {
   1083 			nextproto = *mtod(exthdrs.ip6e_dest1, u_char *);
   1084 			*mtod(exthdrs.ip6e_dest1, u_char *) = IPPROTO_FRAGMENT;
   1085 		} else if (exthdrs.ip6e_hbh) {
   1086 			nextproto = *mtod(exthdrs.ip6e_hbh, u_char *);
   1087 			*mtod(exthdrs.ip6e_hbh, u_char *) = IPPROTO_FRAGMENT;
   1088 		} else {
   1089 			nextproto = ip6->ip6_nxt;
   1090 			ip6->ip6_nxt = IPPROTO_FRAGMENT;
   1091 		}
   1092 
   1093 		if ((m->m_pkthdr.csum_flags & (M_CSUM_UDPv6|M_CSUM_TCPv6))
   1094 		    != 0) {
   1095 			if (IN6_NEED_CHECKSUM(ifp,
   1096 			    m->m_pkthdr.csum_flags &
   1097 			    (M_CSUM_UDPv6|M_CSUM_TCPv6))) {
   1098 				in6_delayed_cksum(m);
   1099 			}
   1100 			m->m_pkthdr.csum_flags &= ~(M_CSUM_UDPv6|M_CSUM_TCPv6);
   1101 		}
   1102 
   1103 		/*
   1104 		 * Loop through length of segment after first fragment,
   1105 		 * make new header and copy data of each part and link onto
   1106 		 * chain.
   1107 		 */
   1108 		m0 = m;
   1109 		for (off = hlen; off < tlen; off += len) {
   1110 			struct mbuf *mlast;
   1111 
   1112 			MGETHDR(m, M_DONTWAIT, MT_HEADER);
   1113 			if (!m) {
   1114 				error = ENOBUFS;
   1115 				ip6stat.ip6s_odropped++;
   1116 				goto sendorfree;
   1117 			}
   1118 			m->m_pkthdr.rcvif = NULL;
   1119 			m->m_flags = m0->m_flags & M_COPYFLAGS;
   1120 			*mnext = m;
   1121 			mnext = &m->m_nextpkt;
   1122 			m->m_data += max_linkhdr;
   1123 			mhip6 = mtod(m, struct ip6_hdr *);
   1124 			*mhip6 = *ip6;
   1125 			m->m_len = sizeof(*mhip6);
   1126 			error = ip6_insertfraghdr(m0, m, hlen, &ip6f);
   1127 			if (error) {
   1128 				ip6stat.ip6s_odropped++;
   1129 				goto sendorfree;
   1130 			}
   1131 			ip6f->ip6f_offlg = htons((u_int16_t)((off - hlen) & ~7));
   1132 			if (off + len >= tlen)
   1133 				len = tlen - off;
   1134 			else
   1135 				ip6f->ip6f_offlg |= IP6F_MORE_FRAG;
   1136 			mhip6->ip6_plen = htons((u_int16_t)(len + hlen +
   1137 			    sizeof(*ip6f) - sizeof(struct ip6_hdr)));
   1138 			if ((m_frgpart = m_copy(m0, off, len)) == 0) {
   1139 				error = ENOBUFS;
   1140 				ip6stat.ip6s_odropped++;
   1141 				goto sendorfree;
   1142 			}
   1143 			for (mlast = m; mlast->m_next; mlast = mlast->m_next)
   1144 				;
   1145 			mlast->m_next = m_frgpart;
   1146 			m->m_pkthdr.len = len + hlen + sizeof(*ip6f);
   1147 			m->m_pkthdr.rcvif = (struct ifnet *)0;
   1148 			ip6f->ip6f_reserved = 0;
   1149 			ip6f->ip6f_ident = id;
   1150 			ip6f->ip6f_nxt = nextproto;
   1151 			ip6stat.ip6s_ofragments++;
   1152 			in6_ifstat_inc(ifp, ifs6_out_fragcreat);
   1153 		}
   1154 
   1155 		in6_ifstat_inc(ifp, ifs6_out_fragok);
   1156 	}
   1157 
   1158 	/*
   1159 	 * Remove leading garbages.
   1160 	 */
   1161 sendorfree:
   1162 	m = m0->m_nextpkt;
   1163 	m0->m_nextpkt = 0;
   1164 	m_freem(m0);
   1165 	for (m0 = m; m; m = m0) {
   1166 		m0 = m->m_nextpkt;
   1167 		m->m_nextpkt = 0;
   1168 		if (error == 0) {
   1169 			struct in6_ifaddr *ia6;
   1170 			ip6 = mtod(m, struct ip6_hdr *);
   1171 			ia6 = in6_ifawithifp(ifp, &ip6->ip6_src);
   1172 			if (ia6) {
   1173 				/*
   1174 				 * Record statistics for this interface
   1175 				 * address.
   1176 				 */
   1177 				ia6->ia_ifa.ifa_data.ifad_outbytes +=
   1178 				    m->m_pkthdr.len;
   1179 			}
   1180 #ifdef IPSEC
   1181 			/* clean ipsec history once it goes out of the node */
   1182 			ipsec_delaux(m);
   1183 #endif
   1184 			KASSERT(dst != NULL);
   1185 			error = nd6_output(ifp, origifp, m, dst, rt);
   1186 		} else
   1187 			m_freem(m);
   1188 	}
   1189 
   1190 	if (error == 0)
   1191 		ip6stat.ip6s_fragmented++;
   1192 
   1193 done:
   1194 	/* XXX Second if is invariant? */
   1195 	if (ro == &ip6route)
   1196 		rtcache_free(ro);
   1197 	else if (ro_pmtu == &ip6route)
   1198 		rtcache_free(ro_pmtu);
   1199 
   1200 #ifdef IPSEC
   1201 	if (sp != NULL)
   1202 		key_freesp(sp);
   1203 #endif /* IPSEC */
   1204 #ifdef FAST_IPSEC
   1205 	if (sp != NULL)
   1206 		KEY_FREESP(&sp);
   1207 #endif /* FAST_IPSEC */
   1208 
   1209 
   1210 	return (error);
   1211 
   1212 freehdrs:
   1213 	m_freem(exthdrs.ip6e_hbh);	/* m_freem will check if mbuf is 0 */
   1214 	m_freem(exthdrs.ip6e_dest1);
   1215 	m_freem(exthdrs.ip6e_rthdr);
   1216 	m_freem(exthdrs.ip6e_dest2);
   1217 	/* FALLTHROUGH */
   1218 bad:
   1219 	m_freem(m);
   1220 	goto done;
   1221 badscope:
   1222 	ip6stat.ip6s_badscope++;
   1223 	in6_ifstat_inc(origifp, ifs6_out_discard);
   1224 	if (error == 0)
   1225 		error = EHOSTUNREACH; /* XXX */
   1226 	goto bad;
   1227 }
   1228 
   1229 static int
   1230 ip6_copyexthdr(struct mbuf **mp, void *hdr, int hlen)
   1231 {
   1232 	struct mbuf *m;
   1233 
   1234 	if (hlen > MCLBYTES)
   1235 		return (ENOBUFS); /* XXX */
   1236 
   1237 	MGET(m, M_DONTWAIT, MT_DATA);
   1238 	if (!m)
   1239 		return (ENOBUFS);
   1240 
   1241 	if (hlen > MLEN) {
   1242 		MCLGET(m, M_DONTWAIT);
   1243 		if ((m->m_flags & M_EXT) == 0) {
   1244 			m_free(m);
   1245 			return (ENOBUFS);
   1246 		}
   1247 	}
   1248 	m->m_len = hlen;
   1249 	if (hdr)
   1250 		bcopy(hdr, mtod(m, void *), hlen);
   1251 
   1252 	*mp = m;
   1253 	return (0);
   1254 }
   1255 
   1256 /*
   1257  * Process a delayed payload checksum calculation.
   1258  */
   1259 void
   1260 in6_delayed_cksum(struct mbuf *m)
   1261 {
   1262 	uint16_t csum, offset;
   1263 
   1264 	KASSERT((m->m_pkthdr.csum_flags & (M_CSUM_UDPv6|M_CSUM_TCPv6)) != 0);
   1265 	KASSERT((~m->m_pkthdr.csum_flags & (M_CSUM_UDPv6|M_CSUM_TCPv6)) != 0);
   1266 	KASSERT((m->m_pkthdr.csum_flags
   1267 	    & (M_CSUM_UDPv4|M_CSUM_TCPv4|M_CSUM_TSOv4)) == 0);
   1268 
   1269 	offset = M_CSUM_DATA_IPv6_HL(m->m_pkthdr.csum_data);
   1270 	csum = in6_cksum(m, 0, offset, m->m_pkthdr.len - offset);
   1271 	if (csum == 0 && (m->m_pkthdr.csum_flags & M_CSUM_UDPv6) != 0) {
   1272 		csum = 0xffff;
   1273 	}
   1274 
   1275 	offset += M_CSUM_DATA_IPv6_OFFSET(m->m_pkthdr.csum_data);
   1276 	if ((offset + sizeof(csum)) > m->m_len) {
   1277 		m_copyback(m, offset, sizeof(csum), &csum);
   1278 	} else {
   1279 		*(uint16_t *)(mtod(m, char *) + offset) = csum;
   1280 	}
   1281 }
   1282 
   1283 /*
   1284  * Insert jumbo payload option.
   1285  */
   1286 static int
   1287 ip6_insert_jumboopt(struct ip6_exthdrs *exthdrs, u_int32_t plen)
   1288 {
   1289 	struct mbuf *mopt;
   1290 	u_int8_t *optbuf;
   1291 	u_int32_t v;
   1292 
   1293 #define JUMBOOPTLEN	8	/* length of jumbo payload option and padding */
   1294 
   1295 	/*
   1296 	 * If there is no hop-by-hop options header, allocate new one.
   1297 	 * If there is one but it doesn't have enough space to store the
   1298 	 * jumbo payload option, allocate a cluster to store the whole options.
   1299 	 * Otherwise, use it to store the options.
   1300 	 */
   1301 	if (exthdrs->ip6e_hbh == 0) {
   1302 		MGET(mopt, M_DONTWAIT, MT_DATA);
   1303 		if (mopt == 0)
   1304 			return (ENOBUFS);
   1305 		mopt->m_len = JUMBOOPTLEN;
   1306 		optbuf = mtod(mopt, u_int8_t *);
   1307 		optbuf[1] = 0;	/* = ((JUMBOOPTLEN) >> 3) - 1 */
   1308 		exthdrs->ip6e_hbh = mopt;
   1309 	} else {
   1310 		struct ip6_hbh *hbh;
   1311 
   1312 		mopt = exthdrs->ip6e_hbh;
   1313 		if (M_TRAILINGSPACE(mopt) < JUMBOOPTLEN) {
   1314 			/*
   1315 			 * XXX assumption:
   1316 			 * - exthdrs->ip6e_hbh is not referenced from places
   1317 			 *   other than exthdrs.
   1318 			 * - exthdrs->ip6e_hbh is not an mbuf chain.
   1319 			 */
   1320 			int oldoptlen = mopt->m_len;
   1321 			struct mbuf *n;
   1322 
   1323 			/*
   1324 			 * XXX: give up if the whole (new) hbh header does
   1325 			 * not fit even in an mbuf cluster.
   1326 			 */
   1327 			if (oldoptlen + JUMBOOPTLEN > MCLBYTES)
   1328 				return (ENOBUFS);
   1329 
   1330 			/*
   1331 			 * As a consequence, we must always prepare a cluster
   1332 			 * at this point.
   1333 			 */
   1334 			MGET(n, M_DONTWAIT, MT_DATA);
   1335 			if (n) {
   1336 				MCLGET(n, M_DONTWAIT);
   1337 				if ((n->m_flags & M_EXT) == 0) {
   1338 					m_freem(n);
   1339 					n = NULL;
   1340 				}
   1341 			}
   1342 			if (!n)
   1343 				return (ENOBUFS);
   1344 			n->m_len = oldoptlen + JUMBOOPTLEN;
   1345 			bcopy(mtod(mopt, void *), mtod(n, void *),
   1346 			    oldoptlen);
   1347 			optbuf = mtod(n, u_int8_t *) + oldoptlen;
   1348 			m_freem(mopt);
   1349 			mopt = exthdrs->ip6e_hbh = n;
   1350 		} else {
   1351 			optbuf = mtod(mopt, u_int8_t *) + mopt->m_len;
   1352 			mopt->m_len += JUMBOOPTLEN;
   1353 		}
   1354 		optbuf[0] = IP6OPT_PADN;
   1355 		optbuf[1] = 0;
   1356 
   1357 		/*
   1358 		 * Adjust the header length according to the pad and
   1359 		 * the jumbo payload option.
   1360 		 */
   1361 		hbh = mtod(mopt, struct ip6_hbh *);
   1362 		hbh->ip6h_len += (JUMBOOPTLEN >> 3);
   1363 	}
   1364 
   1365 	/* fill in the option. */
   1366 	optbuf[2] = IP6OPT_JUMBO;
   1367 	optbuf[3] = 4;
   1368 	v = (u_int32_t)htonl(plen + JUMBOOPTLEN);
   1369 	bcopy(&v, &optbuf[4], sizeof(u_int32_t));
   1370 
   1371 	/* finally, adjust the packet header length */
   1372 	exthdrs->ip6e_ip6->m_pkthdr.len += JUMBOOPTLEN;
   1373 
   1374 	return (0);
   1375 #undef JUMBOOPTLEN
   1376 }
   1377 
   1378 /*
   1379  * Insert fragment header and copy unfragmentable header portions.
   1380  */
   1381 static int
   1382 ip6_insertfraghdr(struct mbuf *m0, struct mbuf *m, int hlen,
   1383 	struct ip6_frag **frghdrp)
   1384 {
   1385 	struct mbuf *n, *mlast;
   1386 
   1387 	if (hlen > sizeof(struct ip6_hdr)) {
   1388 		n = m_copym(m0, sizeof(struct ip6_hdr),
   1389 		    hlen - sizeof(struct ip6_hdr), M_DONTWAIT);
   1390 		if (n == 0)
   1391 			return (ENOBUFS);
   1392 		m->m_next = n;
   1393 	} else
   1394 		n = m;
   1395 
   1396 	/* Search for the last mbuf of unfragmentable part. */
   1397 	for (mlast = n; mlast->m_next; mlast = mlast->m_next)
   1398 		;
   1399 
   1400 	if ((mlast->m_flags & M_EXT) == 0 &&
   1401 	    M_TRAILINGSPACE(mlast) >= sizeof(struct ip6_frag)) {
   1402 		/* use the trailing space of the last mbuf for the fragment hdr */
   1403 		*frghdrp = (struct ip6_frag *)(mtod(mlast, char *) +
   1404 		    mlast->m_len);
   1405 		mlast->m_len += sizeof(struct ip6_frag);
   1406 		m->m_pkthdr.len += sizeof(struct ip6_frag);
   1407 	} else {
   1408 		/* allocate a new mbuf for the fragment header */
   1409 		struct mbuf *mfrg;
   1410 
   1411 		MGET(mfrg, M_DONTWAIT, MT_DATA);
   1412 		if (mfrg == 0)
   1413 			return (ENOBUFS);
   1414 		mfrg->m_len = sizeof(struct ip6_frag);
   1415 		*frghdrp = mtod(mfrg, struct ip6_frag *);
   1416 		mlast->m_next = mfrg;
   1417 	}
   1418 
   1419 	return (0);
   1420 }
   1421 
   1422 static int
   1423 ip6_getpmtu(struct route *ro_pmtu, struct route *ro, struct ifnet *ifp,
   1424     const struct in6_addr *dst, u_long *mtup, int *alwaysfragp)
   1425 {
   1426 	u_int32_t mtu = 0;
   1427 	int alwaysfrag = 0;
   1428 	int error = 0;
   1429 
   1430 	if (ro_pmtu != ro) {
   1431 		union {
   1432 			struct sockaddr		dst;
   1433 			struct sockaddr_in6	dst6;
   1434 		} u;
   1435 
   1436 		/* The first hop and the final destination may differ. */
   1437 		sockaddr_in6_init(&u.dst6, dst, 0, 0, 0);
   1438 		rtcache_lookup(ro_pmtu, &u.dst);
   1439 	}
   1440 	if (ro_pmtu->ro_rt != NULL) {
   1441 		u_int32_t ifmtu;
   1442 
   1443 		if (ifp == NULL)
   1444 			ifp = ro_pmtu->ro_rt->rt_ifp;
   1445 		ifmtu = IN6_LINKMTU(ifp);
   1446 		mtu = ro_pmtu->ro_rt->rt_rmx.rmx_mtu;
   1447 		if (mtu == 0)
   1448 			mtu = ifmtu;
   1449 		else if (mtu < IPV6_MMTU) {
   1450 			/*
   1451 			 * RFC2460 section 5, last paragraph:
   1452 			 * if we record ICMPv6 too big message with
   1453 			 * mtu < IPV6_MMTU, transmit packets sized IPV6_MMTU
   1454 			 * or smaller, with fragment header attached.
   1455 			 * (fragment header is needed regardless from the
   1456 			 * packet size, for translators to identify packets)
   1457 			 */
   1458 			alwaysfrag = 1;
   1459 			mtu = IPV6_MMTU;
   1460 		} else if (mtu > ifmtu) {
   1461 			/*
   1462 			 * The MTU on the route is larger than the MTU on
   1463 			 * the interface!  This shouldn't happen, unless the
   1464 			 * MTU of the interface has been changed after the
   1465 			 * interface was brought up.  Change the MTU in the
   1466 			 * route to match the interface MTU (as long as the
   1467 			 * field isn't locked).
   1468 			 */
   1469 			mtu = ifmtu;
   1470 			if (!(ro_pmtu->ro_rt->rt_rmx.rmx_locks & RTV_MTU))
   1471 				ro_pmtu->ro_rt->rt_rmx.rmx_mtu = mtu;
   1472 		}
   1473 	} else if (ifp) {
   1474 		mtu = IN6_LINKMTU(ifp);
   1475 	} else
   1476 		error = EHOSTUNREACH; /* XXX */
   1477 
   1478 	*mtup = mtu;
   1479 	if (alwaysfragp)
   1480 		*alwaysfragp = alwaysfrag;
   1481 	return (error);
   1482 }
   1483 
   1484 /*
   1485  * IP6 socket option processing.
   1486  */
   1487 int
   1488 ip6_ctloutput(int op, struct socket *so, int level, int optname,
   1489     struct mbuf **mp)
   1490 {
   1491 	int privileged, optdatalen, uproto;
   1492 	void *optdata;
   1493 	struct in6pcb *in6p = sotoin6pcb(so);
   1494 	struct mbuf *m = *mp;
   1495 	int error, optval;
   1496 	int optlen;
   1497 	struct lwp *l = curlwp;	/* XXX */
   1498 
   1499 	optlen = m ? m->m_len : 0;
   1500 	error = optval = 0;
   1501 	privileged = (l == 0 || kauth_authorize_generic(l->l_cred,
   1502 	    KAUTH_GENERIC_ISSUSER, NULL)) ? 0 : 1;
   1503 	uproto = (int)so->so_proto->pr_protocol;
   1504 
   1505 	if (level == IPPROTO_IPV6) {
   1506 		switch (op) {
   1507 		case PRCO_SETOPT:
   1508 			switch (optname) {
   1509 #ifdef RFC2292
   1510 			case IPV6_2292PKTOPTIONS:
   1511 				/* m is freed in ip6_pcbopts */
   1512 				error = ip6_pcbopts(&in6p->in6p_outputopts,
   1513 				    m, so);
   1514 				break;
   1515 #endif
   1516 
   1517 			/*
   1518 			 * Use of some Hop-by-Hop options or some
   1519 			 * Destination options, might require special
   1520 			 * privilege.  That is, normal applications
   1521 			 * (without special privilege) might be forbidden
   1522 			 * from setting certain options in outgoing packets,
   1523 			 * and might never see certain options in received
   1524 			 * packets. [RFC 2292 Section 6]
   1525 			 * KAME specific note:
   1526 			 *  KAME prevents non-privileged users from sending or
   1527 			 *  receiving ANY hbh/dst options in order to avoid
   1528 			 *  overhead of parsing options in the kernel.
   1529 			 */
   1530 			case IPV6_RECVHOPOPTS:
   1531 			case IPV6_RECVDSTOPTS:
   1532 			case IPV6_RECVRTHDRDSTOPTS:
   1533 				if (!privileged) {
   1534 					error = EPERM;
   1535 					break;
   1536 				}
   1537 				/* FALLTHROUGH */
   1538 			case IPV6_UNICAST_HOPS:
   1539 			case IPV6_HOPLIMIT:
   1540 			case IPV6_FAITH:
   1541 
   1542 			case IPV6_RECVPKTINFO:
   1543 			case IPV6_RECVHOPLIMIT:
   1544 			case IPV6_RECVRTHDR:
   1545 			case IPV6_RECVPATHMTU:
   1546 			case IPV6_RECVTCLASS:
   1547 			case IPV6_V6ONLY:
   1548 				if (optlen != sizeof(int)) {
   1549 					error = EINVAL;
   1550 					break;
   1551 				}
   1552 				optval = *mtod(m, int *);
   1553 				switch (optname) {
   1554 
   1555 				case IPV6_UNICAST_HOPS:
   1556 					if (optval < -1 || optval >= 256)
   1557 						error = EINVAL;
   1558 					else {
   1559 						/* -1 = kernel default */
   1560 						in6p->in6p_hops = optval;
   1561 					}
   1562 					break;
   1563 #define OPTSET(bit) \
   1564 do { \
   1565 	if (optval) \
   1566 		in6p->in6p_flags |= (bit); \
   1567 	else \
   1568 		in6p->in6p_flags &= ~(bit); \
   1569 } while (/*CONSTCOND*/ 0)
   1570 
   1571 #ifdef RFC2292
   1572 #define OPTSET2292(bit) 			\
   1573 do { 						\
   1574 	in6p->in6p_flags |= IN6P_RFC2292; 	\
   1575 	if (optval) 				\
   1576 		in6p->in6p_flags |= (bit); 	\
   1577 	else 					\
   1578 		in6p->in6p_flags &= ~(bit); 	\
   1579 } while (/*CONSTCOND*/ 0)
   1580 #endif
   1581 
   1582 #define OPTBIT(bit) (in6p->in6p_flags & (bit) ? 1 : 0)
   1583 
   1584 				case IPV6_RECVPKTINFO:
   1585 #ifdef RFC2292
   1586 					/* cannot mix with RFC2292 */
   1587 					if (OPTBIT(IN6P_RFC2292)) {
   1588 						error = EINVAL;
   1589 						break;
   1590 					}
   1591 #endif
   1592 					OPTSET(IN6P_PKTINFO);
   1593 					break;
   1594 
   1595 				case IPV6_HOPLIMIT:
   1596 				{
   1597 					struct ip6_pktopts **optp;
   1598 
   1599 #ifdef RFC2292
   1600 					/* cannot mix with RFC2292 */
   1601 					if (OPTBIT(IN6P_RFC2292)) {
   1602 						error = EINVAL;
   1603 						break;
   1604 					}
   1605 #endif
   1606 					optp = &in6p->in6p_outputopts;
   1607 					error = ip6_pcbopt(IPV6_HOPLIMIT,
   1608 							   (u_char *)&optval,
   1609 							   sizeof(optval),
   1610 							   optp,
   1611 							   privileged, uproto);
   1612 					break;
   1613 				}
   1614 
   1615 				case IPV6_RECVHOPLIMIT:
   1616 #ifdef RFC2292
   1617 					/* cannot mix with RFC2292 */
   1618 					if (OPTBIT(IN6P_RFC2292)) {
   1619 						error = EINVAL;
   1620 						break;
   1621 					}
   1622 #endif
   1623 					OPTSET(IN6P_HOPLIMIT);
   1624 					break;
   1625 
   1626 				case IPV6_RECVHOPOPTS:
   1627 #ifdef RFC2292
   1628 					/* cannot mix with RFC2292 */
   1629 					if (OPTBIT(IN6P_RFC2292)) {
   1630 						error = EINVAL;
   1631 						break;
   1632 					}
   1633 #endif
   1634 					OPTSET(IN6P_HOPOPTS);
   1635 					break;
   1636 
   1637 				case IPV6_RECVDSTOPTS:
   1638 #ifdef RFC2292
   1639 					/* cannot mix with RFC2292 */
   1640 					if (OPTBIT(IN6P_RFC2292)) {
   1641 						error = EINVAL;
   1642 						break;
   1643 					}
   1644 #endif
   1645 					OPTSET(IN6P_DSTOPTS);
   1646 					break;
   1647 
   1648 				case IPV6_RECVRTHDRDSTOPTS:
   1649 #ifdef RFC2292
   1650 					/* cannot mix with RFC2292 */
   1651 					if (OPTBIT(IN6P_RFC2292)) {
   1652 						error = EINVAL;
   1653 						break;
   1654 					}
   1655 #endif
   1656 					OPTSET(IN6P_RTHDRDSTOPTS);
   1657 					break;
   1658 
   1659 				case IPV6_RECVRTHDR:
   1660 #ifdef RFC2292
   1661 					/* cannot mix with RFC2292 */
   1662 					if (OPTBIT(IN6P_RFC2292)) {
   1663 						error = EINVAL;
   1664 						break;
   1665 					}
   1666 #endif
   1667 					OPTSET(IN6P_RTHDR);
   1668 					break;
   1669 
   1670 				case IPV6_FAITH:
   1671 					OPTSET(IN6P_FAITH);
   1672 					break;
   1673 
   1674 				case IPV6_RECVPATHMTU:
   1675 					/*
   1676 					 * We ignore this option for TCP
   1677 					 * sockets.
   1678 					 * (RFC3542 leaves this case
   1679 					 * unspecified.)
   1680 					 */
   1681 					if (uproto != IPPROTO_TCP)
   1682 						OPTSET(IN6P_MTU);
   1683 					break;
   1684 
   1685 				case IPV6_V6ONLY:
   1686 					/*
   1687 					 * make setsockopt(IPV6_V6ONLY)
   1688 					 * available only prior to bind(2).
   1689 					 * see ipng mailing list, Jun 22 2001.
   1690 					 */
   1691 					if (in6p->in6p_lport ||
   1692 					    !IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_laddr)) {
   1693 						error = EINVAL;
   1694 						break;
   1695 					}
   1696 #ifdef INET6_BINDV6ONLY
   1697 					if (!optval)
   1698 						error = EINVAL;
   1699 #else
   1700 					OPTSET(IN6P_IPV6_V6ONLY);
   1701 #endif
   1702 					break;
   1703 				case IPV6_RECVTCLASS:
   1704 #ifdef RFC2292
   1705 					/* cannot mix with RFC2292 XXX */
   1706 					if (OPTBIT(IN6P_RFC2292)) {
   1707 						error = EINVAL;
   1708 						break;
   1709 					}
   1710 #endif
   1711 					OPTSET(IN6P_TCLASS);
   1712 					break;
   1713 
   1714 				}
   1715 				break;
   1716 
   1717 			case IPV6_OTCLASS:
   1718 			{
   1719 				struct ip6_pktopts **optp;
   1720 				u_int8_t tclass;
   1721 
   1722 				if (optlen != sizeof(tclass)) {
   1723 					error = EINVAL;
   1724 					break;
   1725 				}
   1726 				tclass = *mtod(m, u_int8_t *);
   1727 				optp = &in6p->in6p_outputopts;
   1728 				error = ip6_pcbopt(optname,
   1729 						   (u_char *)&tclass,
   1730 						   sizeof(tclass),
   1731 						   optp,
   1732 						   privileged, uproto);
   1733 				break;
   1734 			}
   1735 
   1736 			case IPV6_TCLASS:
   1737 			case IPV6_DONTFRAG:
   1738 			case IPV6_USE_MIN_MTU:
   1739 				if (optlen != sizeof(optval)) {
   1740 					error = EINVAL;
   1741 					break;
   1742 				}
   1743 				optval = *mtod(m, int *);
   1744 				{
   1745 					struct ip6_pktopts **optp;
   1746 					optp = &in6p->in6p_outputopts;
   1747 					error = ip6_pcbopt(optname,
   1748 							   (u_char *)&optval,
   1749 							   sizeof(optval),
   1750 							   optp,
   1751 							   privileged, uproto);
   1752 					break;
   1753 				}
   1754 
   1755 #ifdef RFC2292
   1756 			case IPV6_2292PKTINFO:
   1757 			case IPV6_2292HOPLIMIT:
   1758 			case IPV6_2292HOPOPTS:
   1759 			case IPV6_2292DSTOPTS:
   1760 			case IPV6_2292RTHDR:
   1761 				/* RFC 2292 */
   1762 				if (optlen != sizeof(int)) {
   1763 					error = EINVAL;
   1764 					break;
   1765 				}
   1766 				optval = *mtod(m, int *);
   1767 				switch (optname) {
   1768 				case IPV6_2292PKTINFO:
   1769 					OPTSET2292(IN6P_PKTINFO);
   1770 					break;
   1771 				case IPV6_2292HOPLIMIT:
   1772 					OPTSET2292(IN6P_HOPLIMIT);
   1773 					break;
   1774 				case IPV6_2292HOPOPTS:
   1775 					/*
   1776 					 * Check super-user privilege.
   1777 					 * See comments for IPV6_RECVHOPOPTS.
   1778 					 */
   1779 					if (!privileged)
   1780 						return (EPERM);
   1781 					OPTSET2292(IN6P_HOPOPTS);
   1782 					break;
   1783 				case IPV6_2292DSTOPTS:
   1784 					if (!privileged)
   1785 						return (EPERM);
   1786 					OPTSET2292(IN6P_DSTOPTS|IN6P_RTHDRDSTOPTS); /* XXX */
   1787 					break;
   1788 				case IPV6_2292RTHDR:
   1789 					OPTSET2292(IN6P_RTHDR);
   1790 					break;
   1791 				}
   1792 				break;
   1793 #endif
   1794 			case IPV6_PKTINFO:
   1795 			case IPV6_HOPOPTS:
   1796 			case IPV6_RTHDR:
   1797 			case IPV6_DSTOPTS:
   1798 			case IPV6_RTHDRDSTOPTS:
   1799 			case IPV6_NEXTHOP:
   1800 			{
   1801 				/* new advanced API (RFC3542) */
   1802 				u_char *optbuf;
   1803 				int optbuflen;
   1804 				struct ip6_pktopts **optp;
   1805 				if (!m) {
   1806 					error = EINVAL;
   1807 					break;
   1808 				}
   1809 
   1810 #ifdef RFC2292
   1811 				/* cannot mix with RFC2292 */
   1812 				if (OPTBIT(IN6P_RFC2292)) {
   1813 					error = EINVAL;
   1814 					break;
   1815 				}
   1816 #endif
   1817 
   1818 				if (m && m->m_next) {
   1819 					error = EINVAL;	/* XXX */
   1820 					break;
   1821 				}
   1822 
   1823 				optbuf = mtod(m, u_char *);
   1824 				optbuflen = m->m_len;
   1825 				optp = &in6p->in6p_outputopts;
   1826 				error = ip6_pcbopt(optname, optbuf, optbuflen,
   1827 				    optp, privileged, uproto);
   1828 				break;
   1829 			}
   1830 #undef OPTSET
   1831 
   1832 			case IPV6_MULTICAST_IF:
   1833 			case IPV6_MULTICAST_HOPS:
   1834 			case IPV6_MULTICAST_LOOP:
   1835 			case IPV6_JOIN_GROUP:
   1836 			case IPV6_LEAVE_GROUP:
   1837                                 error = ip6_setmoptions(optname,
   1838 				    &in6p->in6p_moptions, m);
   1839 				break;
   1840 
   1841 			case IPV6_PORTRANGE:
   1842 				if (!m) {
   1843 					error = EINVAL;
   1844 					break;
   1845 				}
   1846 				optval = *mtod(m, int *);
   1847 
   1848 				switch (optval) {
   1849 				case IPV6_PORTRANGE_DEFAULT:
   1850 					in6p->in6p_flags &= ~(IN6P_LOWPORT);
   1851 					in6p->in6p_flags &= ~(IN6P_HIGHPORT);
   1852 					break;
   1853 
   1854 				case IPV6_PORTRANGE_HIGH:
   1855 					in6p->in6p_flags &= ~(IN6P_LOWPORT);
   1856 					in6p->in6p_flags |= IN6P_HIGHPORT;
   1857 					break;
   1858 
   1859 				case IPV6_PORTRANGE_LOW:
   1860 					in6p->in6p_flags &= ~(IN6P_HIGHPORT);
   1861 					in6p->in6p_flags |= IN6P_LOWPORT;
   1862 					break;
   1863 
   1864 				default:
   1865 					error = EINVAL;
   1866 					break;
   1867 				}
   1868 				break;
   1869 
   1870 
   1871 #if defined(IPSEC) || defined(FAST_IPSEC)
   1872 			case IPV6_IPSEC_POLICY:
   1873 			{
   1874 				void *req = NULL;
   1875 				size_t len = 0;
   1876 				if (m) {
   1877 					req = mtod(m, void *);
   1878 					len = m->m_len;
   1879 				}
   1880 				error = ipsec6_set_policy(in6p, optname, req,
   1881 							  len, privileged);
   1882 			}
   1883 				break;
   1884 #endif /* IPSEC */
   1885 
   1886 			default:
   1887 				error = ENOPROTOOPT;
   1888 				break;
   1889 			}
   1890 			if (m)
   1891 				(void)m_free(m);
   1892 			break;
   1893 
   1894 		case PRCO_GETOPT:
   1895 			switch (optname) {
   1896 #ifdef RFC2292
   1897 			case IPV6_2292PKTOPTIONS:
   1898 				/*
   1899 				 * RFC3542 (effectively) deprecated the
   1900 				 * semantics of the 2292-style pktoptions.
   1901 				 * Since it was not reliable in nature (i.e.,
   1902 				 * applications had to expect the lack of some
   1903 				 * information after all), it would make sense
   1904 				 * to simplify this part by always returning
   1905 				 * empty data.
   1906 				 */
   1907 				*mp = m_get(M_WAIT, MT_SOOPTS);
   1908 				(*mp)->m_len = 0;
   1909 				break;
   1910 #endif
   1911 
   1912 			case IPV6_RECVHOPOPTS:
   1913 			case IPV6_RECVDSTOPTS:
   1914 			case IPV6_RECVRTHDRDSTOPTS:
   1915 			case IPV6_UNICAST_HOPS:
   1916 			case IPV6_RECVPKTINFO:
   1917 			case IPV6_RECVHOPLIMIT:
   1918 			case IPV6_RECVRTHDR:
   1919 			case IPV6_RECVPATHMTU:
   1920 
   1921 			case IPV6_FAITH:
   1922 			case IPV6_V6ONLY:
   1923 			case IPV6_PORTRANGE:
   1924 			case IPV6_RECVTCLASS:
   1925 				switch (optname) {
   1926 
   1927 				case IPV6_RECVHOPOPTS:
   1928 					optval = OPTBIT(IN6P_HOPOPTS);
   1929 					break;
   1930 
   1931 				case IPV6_RECVDSTOPTS:
   1932 					optval = OPTBIT(IN6P_DSTOPTS);
   1933 					break;
   1934 
   1935 				case IPV6_RECVRTHDRDSTOPTS:
   1936 					optval = OPTBIT(IN6P_RTHDRDSTOPTS);
   1937 					break;
   1938 
   1939 				case IPV6_UNICAST_HOPS:
   1940 					optval = in6p->in6p_hops;
   1941 					break;
   1942 
   1943 				case IPV6_RECVPKTINFO:
   1944 					optval = OPTBIT(IN6P_PKTINFO);
   1945 					break;
   1946 
   1947 				case IPV6_RECVHOPLIMIT:
   1948 					optval = OPTBIT(IN6P_HOPLIMIT);
   1949 					break;
   1950 
   1951 				case IPV6_RECVRTHDR:
   1952 					optval = OPTBIT(IN6P_RTHDR);
   1953 					break;
   1954 
   1955 				case IPV6_RECVPATHMTU:
   1956 					optval = OPTBIT(IN6P_MTU);
   1957 					break;
   1958 
   1959 				case IPV6_FAITH:
   1960 					optval = OPTBIT(IN6P_FAITH);
   1961 					break;
   1962 
   1963 				case IPV6_V6ONLY:
   1964 					optval = OPTBIT(IN6P_IPV6_V6ONLY);
   1965 					break;
   1966 
   1967 				case IPV6_PORTRANGE:
   1968 				    {
   1969 					int flags;
   1970 					flags = in6p->in6p_flags;
   1971 					if (flags & IN6P_HIGHPORT)
   1972 						optval = IPV6_PORTRANGE_HIGH;
   1973 					else if (flags & IN6P_LOWPORT)
   1974 						optval = IPV6_PORTRANGE_LOW;
   1975 					else
   1976 						optval = 0;
   1977 					break;
   1978 				    }
   1979 				case IPV6_RECVTCLASS:
   1980 					optval = OPTBIT(IN6P_TCLASS);
   1981 					break;
   1982 
   1983 				}
   1984 				if (error)
   1985 					break;
   1986 				*mp = m = m_get(M_WAIT, MT_SOOPTS);
   1987 				m->m_len = sizeof(int);
   1988 				*mtod(m, int *) = optval;
   1989 				break;
   1990 
   1991 			case IPV6_PATHMTU:
   1992 			    {
   1993 				u_long pmtu = 0;
   1994 				struct ip6_mtuinfo mtuinfo;
   1995 				struct route *ro = &in6p->in6p_route;
   1996 
   1997 				if (!(so->so_state & SS_ISCONNECTED))
   1998 					return (ENOTCONN);
   1999 				/*
   2000 				 * XXX: we dot not consider the case of source
   2001 				 * routing, or optional information to specify
   2002 				 * the outgoing interface.
   2003 				 */
   2004 				error = ip6_getpmtu(ro, NULL, NULL,
   2005 				    &in6p->in6p_faddr, &pmtu, NULL);
   2006 				if (error)
   2007 					break;
   2008 				if (pmtu > IPV6_MAXPACKET)
   2009 					pmtu = IPV6_MAXPACKET;
   2010 
   2011 				memset(&mtuinfo, 0, sizeof(mtuinfo));
   2012 				mtuinfo.ip6m_mtu = (u_int32_t)pmtu;
   2013 				optdata = (void *)&mtuinfo;
   2014 				optdatalen = sizeof(mtuinfo);
   2015 				if (optdatalen > MCLBYTES)
   2016 					return (EMSGSIZE); /* XXX */
   2017 				*mp = m = m_get(M_WAIT, MT_SOOPTS);
   2018 				if (optdatalen > MLEN)
   2019 					MCLGET(m, M_WAIT);
   2020 				m->m_len = optdatalen;
   2021 				memcpy(mtod(m, void *), optdata, optdatalen);
   2022 				break;
   2023 			    }
   2024 
   2025 #ifdef RFC2292
   2026 			case IPV6_2292PKTINFO:
   2027 			case IPV6_2292HOPLIMIT:
   2028 			case IPV6_2292HOPOPTS:
   2029 			case IPV6_2292RTHDR:
   2030 			case IPV6_2292DSTOPTS:
   2031 				switch (optname) {
   2032 				case IPV6_2292PKTINFO:
   2033 					optval = OPTBIT(IN6P_PKTINFO);
   2034 					break;
   2035 				case IPV6_2292HOPLIMIT:
   2036 					optval = OPTBIT(IN6P_HOPLIMIT);
   2037 					break;
   2038 				case IPV6_2292HOPOPTS:
   2039 					optval = OPTBIT(IN6P_HOPOPTS);
   2040 					break;
   2041 				case IPV6_2292RTHDR:
   2042 					optval = OPTBIT(IN6P_RTHDR);
   2043 					break;
   2044 				case IPV6_2292DSTOPTS:
   2045 					optval = OPTBIT(IN6P_DSTOPTS|IN6P_RTHDRDSTOPTS);
   2046 					break;
   2047 				}
   2048 				*mp = m = m_get(M_WAIT, MT_SOOPTS);
   2049 				m->m_len = sizeof(int);
   2050 				*mtod(m, int *) = optval;
   2051 				break;
   2052 #endif
   2053 			case IPV6_PKTINFO:
   2054 			case IPV6_HOPOPTS:
   2055 			case IPV6_RTHDR:
   2056 			case IPV6_DSTOPTS:
   2057 			case IPV6_RTHDRDSTOPTS:
   2058 			case IPV6_NEXTHOP:
   2059 			case IPV6_OTCLASS:
   2060 			case IPV6_TCLASS:
   2061 			case IPV6_DONTFRAG:
   2062 			case IPV6_USE_MIN_MTU:
   2063 				error = ip6_getpcbopt(in6p->in6p_outputopts,
   2064 				    optname, mp);
   2065 				break;
   2066 
   2067 			case IPV6_MULTICAST_IF:
   2068 			case IPV6_MULTICAST_HOPS:
   2069 			case IPV6_MULTICAST_LOOP:
   2070 			case IPV6_JOIN_GROUP:
   2071 			case IPV6_LEAVE_GROUP:
   2072 				error = ip6_getmoptions(optname,
   2073 				    in6p->in6p_moptions, mp);
   2074 				break;
   2075 
   2076 #if defined(IPSEC) || defined(FAST_IPSEC)
   2077 			case IPV6_IPSEC_POLICY:
   2078 			    {
   2079 				void *req = NULL;
   2080 				size_t len = 0;
   2081 				if (m) {
   2082 					req = mtod(m, void *);
   2083 					len = m->m_len;
   2084 				}
   2085 				error = ipsec6_get_policy(in6p, req, len, mp);
   2086 				break;
   2087 			    }
   2088 #endif /* IPSEC */
   2089 
   2090 
   2091 
   2092 
   2093 			default:
   2094 				error = ENOPROTOOPT;
   2095 				break;
   2096 			}
   2097 			break;
   2098 		}
   2099 	} else {
   2100 		error = EINVAL;
   2101 		if (op == PRCO_SETOPT && *mp)
   2102 			(void)m_free(*mp);
   2103 	}
   2104 	return (error);
   2105 }
   2106 
   2107 int
   2108 ip6_raw_ctloutput(int op, struct socket *so, int level, int optname,
   2109 	struct mbuf **mp)
   2110 {
   2111 	int error = 0, optval, optlen;
   2112 	const int icmp6off = offsetof(struct icmp6_hdr, icmp6_cksum);
   2113 	struct in6pcb *in6p = sotoin6pcb(so);
   2114 	struct mbuf *m = *mp;
   2115 
   2116 	optlen = m ? m->m_len : 0;
   2117 
   2118 	if (level != IPPROTO_IPV6) {
   2119 		if (op == PRCO_SETOPT && *mp)
   2120 			(void)m_free(*mp);
   2121 		return (EINVAL);
   2122 	}
   2123 
   2124 	switch (optname) {
   2125 	case IPV6_CHECKSUM:
   2126 		/*
   2127 		 * For ICMPv6 sockets, no modification allowed for checksum
   2128 		 * offset, permit "no change" values to help existing apps.
   2129 		 *
   2130 		 * XXX RFC3542 says: "An attempt to set IPV6_CHECKSUM
   2131 		 * for an ICMPv6 socket will fail."  The current
   2132 		 * behavior does not meet RFC3542.
   2133 		 */
   2134 		switch (op) {
   2135 		case PRCO_SETOPT:
   2136 			if (optlen != sizeof(int)) {
   2137 				error = EINVAL;
   2138 				break;
   2139 			}
   2140 			optval = *mtod(m, int *);
   2141 			if ((optval % 2) != 0) {
   2142 				/* the API assumes even offset values */
   2143 				error = EINVAL;
   2144 			} else if (so->so_proto->pr_protocol ==
   2145 			    IPPROTO_ICMPV6) {
   2146 				if (optval != icmp6off)
   2147 					error = EINVAL;
   2148 			} else
   2149 				in6p->in6p_cksum = optval;
   2150 			break;
   2151 
   2152 		case PRCO_GETOPT:
   2153 			if (so->so_proto->pr_protocol == IPPROTO_ICMPV6)
   2154 				optval = icmp6off;
   2155 			else
   2156 				optval = in6p->in6p_cksum;
   2157 
   2158 			*mp = m = m_get(M_WAIT, MT_SOOPTS);
   2159 			m->m_len = sizeof(int);
   2160 			*mtod(m, int *) = optval;
   2161 			break;
   2162 
   2163 		default:
   2164 			error = EINVAL;
   2165 			break;
   2166 		}
   2167 		break;
   2168 
   2169 	default:
   2170 		error = ENOPROTOOPT;
   2171 		break;
   2172 	}
   2173 
   2174 	if (op == PRCO_SETOPT && m)
   2175 		(void)m_free(m);
   2176 
   2177 	return (error);
   2178 }
   2179 
   2180 #ifdef RFC2292
   2181 /*
   2182  * Set up IP6 options in pcb for insertion in output packets or
   2183  * specifying behavior of outgoing packets.
   2184  */
   2185 static int
   2186 ip6_pcbopts(struct ip6_pktopts **pktopt, struct mbuf *m, struct socket *so)
   2187 {
   2188 	struct ip6_pktopts *opt = *pktopt;
   2189 	int error = 0;
   2190 	struct lwp *l = curlwp;	/* XXX */
   2191 	int priv = 0;
   2192 
   2193 	/* turn off any old options. */
   2194 	if (opt) {
   2195 #ifdef DIAGNOSTIC
   2196 	    if (opt->ip6po_pktinfo || opt->ip6po_nexthop ||
   2197 		opt->ip6po_hbh || opt->ip6po_dest1 || opt->ip6po_dest2 ||
   2198 		opt->ip6po_rhinfo.ip6po_rhi_rthdr)
   2199 		    printf("ip6_pcbopts: all specified options are cleared.\n");
   2200 #endif
   2201 		ip6_clearpktopts(opt, -1);
   2202 	} else
   2203 		opt = malloc(sizeof(*opt), M_IP6OPT, M_WAITOK);
   2204 	*pktopt = NULL;
   2205 
   2206 	if (!m || m->m_len == 0) {
   2207 		/*
   2208 		 * Only turning off any previous options, regardless of
   2209 		 * whether the opt is just created or given.
   2210 		 */
   2211 		free(opt, M_IP6OPT);
   2212 		return (0);
   2213 	}
   2214 
   2215 	/*  set options specified by user. */
   2216 	if (l && !kauth_authorize_generic(l->l_cred, KAUTH_GENERIC_ISSUSER,
   2217 	    NULL))
   2218 		priv = 1;
   2219 	if ((error = ip6_setpktopts(m, opt, NULL, priv,
   2220 	    so->so_proto->pr_protocol)) != 0) {
   2221 		ip6_clearpktopts(opt, -1); /* XXX: discard all options */
   2222 		free(opt, M_IP6OPT);
   2223 		return (error);
   2224 	}
   2225 	*pktopt = opt;
   2226 	return (0);
   2227 }
   2228 #endif
   2229 
   2230 /*
   2231  * initialize ip6_pktopts.  beware that there are non-zero default values in
   2232  * the struct.
   2233  */
   2234 void
   2235 ip6_initpktopts(struct ip6_pktopts *opt)
   2236 {
   2237 
   2238 	memset(opt, 0, sizeof(*opt));
   2239 	opt->ip6po_hlim = -1;	/* -1 means default hop limit */
   2240 	opt->ip6po_tclass = -1;	/* -1 means default traffic class */
   2241 	opt->ip6po_minmtu = IP6PO_MINMTU_MCASTONLY;
   2242 }
   2243 
   2244 #define sin6tosa(sin6)	((struct sockaddr *)(sin6)) /* XXX */
   2245 static int
   2246 ip6_pcbopt(int optname, u_char *buf, int len, struct ip6_pktopts **pktopt,
   2247     int priv, int uproto)
   2248 {
   2249 	struct ip6_pktopts *opt;
   2250 
   2251 	if (*pktopt == NULL) {
   2252 		*pktopt = malloc(sizeof(struct ip6_pktopts), M_IP6OPT,
   2253 		    M_WAITOK);
   2254 		ip6_initpktopts(*pktopt);
   2255 	}
   2256 	opt = *pktopt;
   2257 
   2258 	return (ip6_setpktopt(optname, buf, len, opt, priv, 1, 0, uproto));
   2259 }
   2260 
   2261 static int
   2262 ip6_getpcbopt(struct ip6_pktopts *pktopt, int optname, struct mbuf **mp)
   2263 {
   2264 	void *optdata = NULL;
   2265 	int optdatalen = 0;
   2266 	struct ip6_ext *ip6e;
   2267 	int error = 0;
   2268 	struct in6_pktinfo null_pktinfo;
   2269 	int deftclass = 0, on;
   2270 	int defminmtu = IP6PO_MINMTU_MCASTONLY;
   2271 	struct mbuf *m;
   2272 
   2273 	switch (optname) {
   2274 	case IPV6_PKTINFO:
   2275 		if (pktopt && pktopt->ip6po_pktinfo)
   2276 			optdata = (void *)pktopt->ip6po_pktinfo;
   2277 		else {
   2278 			/* XXX: we don't have to do this every time... */
   2279 			memset(&null_pktinfo, 0, sizeof(null_pktinfo));
   2280 			optdata = (void *)&null_pktinfo;
   2281 		}
   2282 		optdatalen = sizeof(struct in6_pktinfo);
   2283 		break;
   2284 	case IPV6_OTCLASS:
   2285 		/* XXX */
   2286 		return (EINVAL);
   2287 	case IPV6_TCLASS:
   2288 		if (pktopt && pktopt->ip6po_tclass >= 0)
   2289 			optdata = (void *)&pktopt->ip6po_tclass;
   2290 		else
   2291 			optdata = (void *)&deftclass;
   2292 		optdatalen = sizeof(int);
   2293 		break;
   2294 	case IPV6_HOPOPTS:
   2295 		if (pktopt && pktopt->ip6po_hbh) {
   2296 			optdata = (void *)pktopt->ip6po_hbh;
   2297 			ip6e = (struct ip6_ext *)pktopt->ip6po_hbh;
   2298 			optdatalen = (ip6e->ip6e_len + 1) << 3;
   2299 		}
   2300 		break;
   2301 	case IPV6_RTHDR:
   2302 		if (pktopt && pktopt->ip6po_rthdr) {
   2303 			optdata = (void *)pktopt->ip6po_rthdr;
   2304 			ip6e = (struct ip6_ext *)pktopt->ip6po_rthdr;
   2305 			optdatalen = (ip6e->ip6e_len + 1) << 3;
   2306 		}
   2307 		break;
   2308 	case IPV6_RTHDRDSTOPTS:
   2309 		if (pktopt && pktopt->ip6po_dest1) {
   2310 			optdata = (void *)pktopt->ip6po_dest1;
   2311 			ip6e = (struct ip6_ext *)pktopt->ip6po_dest1;
   2312 			optdatalen = (ip6e->ip6e_len + 1) << 3;
   2313 		}
   2314 		break;
   2315 	case IPV6_DSTOPTS:
   2316 		if (pktopt && pktopt->ip6po_dest2) {
   2317 			optdata = (void *)pktopt->ip6po_dest2;
   2318 			ip6e = (struct ip6_ext *)pktopt->ip6po_dest2;
   2319 			optdatalen = (ip6e->ip6e_len + 1) << 3;
   2320 		}
   2321 		break;
   2322 	case IPV6_NEXTHOP:
   2323 		if (pktopt && pktopt->ip6po_nexthop) {
   2324 			optdata = (void *)pktopt->ip6po_nexthop;
   2325 			optdatalen = pktopt->ip6po_nexthop->sa_len;
   2326 		}
   2327 		break;
   2328 	case IPV6_USE_MIN_MTU:
   2329 		if (pktopt)
   2330 			optdata = (void *)&pktopt->ip6po_minmtu;
   2331 		else
   2332 			optdata = (void *)&defminmtu;
   2333 		optdatalen = sizeof(int);
   2334 		break;
   2335 	case IPV6_DONTFRAG:
   2336 		if (pktopt && ((pktopt->ip6po_flags) & IP6PO_DONTFRAG))
   2337 			on = 1;
   2338 		else
   2339 			on = 0;
   2340 		optdata = (void *)&on;
   2341 		optdatalen = sizeof(on);
   2342 		break;
   2343 	default:		/* should not happen */
   2344 #ifdef DIAGNOSTIC
   2345 		panic("ip6_getpcbopt: unexpected option\n");
   2346 #endif
   2347 		return (ENOPROTOOPT);
   2348 	}
   2349 
   2350 	if (optdatalen > MCLBYTES)
   2351 		return (EMSGSIZE); /* XXX */
   2352 	*mp = m = m_get(M_WAIT, MT_SOOPTS);
   2353 	if (optdatalen > MLEN)
   2354 		MCLGET(m, M_WAIT);
   2355 	m->m_len = optdatalen;
   2356 	if (optdatalen)
   2357 		memcpy(mtod(m, void *), optdata, optdatalen);
   2358 
   2359 	return (error);
   2360 }
   2361 
   2362 void
   2363 ip6_clearpktopts(struct ip6_pktopts *pktopt, int optname)
   2364 {
   2365 	if (optname == -1 || optname == IPV6_PKTINFO) {
   2366 		if (pktopt->ip6po_pktinfo)
   2367 			free(pktopt->ip6po_pktinfo, M_IP6OPT);
   2368 		pktopt->ip6po_pktinfo = NULL;
   2369 	}
   2370 	if (optname == -1 || optname == IPV6_HOPLIMIT)
   2371 		pktopt->ip6po_hlim = -1;
   2372 	if (optname == -1 || optname == IPV6_TCLASS)
   2373 		pktopt->ip6po_tclass = -1;
   2374 	if (optname == -1 || optname == IPV6_NEXTHOP) {
   2375 		rtcache_free(&pktopt->ip6po_nextroute);
   2376 		if (pktopt->ip6po_nexthop)
   2377 			free(pktopt->ip6po_nexthop, M_IP6OPT);
   2378 		pktopt->ip6po_nexthop = NULL;
   2379 	}
   2380 	if (optname == -1 || optname == IPV6_HOPOPTS) {
   2381 		if (pktopt->ip6po_hbh)
   2382 			free(pktopt->ip6po_hbh, M_IP6OPT);
   2383 		pktopt->ip6po_hbh = NULL;
   2384 	}
   2385 	if (optname == -1 || optname == IPV6_RTHDRDSTOPTS) {
   2386 		if (pktopt->ip6po_dest1)
   2387 			free(pktopt->ip6po_dest1, M_IP6OPT);
   2388 		pktopt->ip6po_dest1 = NULL;
   2389 	}
   2390 	if (optname == -1 || optname == IPV6_RTHDR) {
   2391 		if (pktopt->ip6po_rhinfo.ip6po_rhi_rthdr)
   2392 			free(pktopt->ip6po_rhinfo.ip6po_rhi_rthdr, M_IP6OPT);
   2393 		pktopt->ip6po_rhinfo.ip6po_rhi_rthdr = NULL;
   2394 		rtcache_free(&pktopt->ip6po_route);
   2395 	}
   2396 	if (optname == -1 || optname == IPV6_DSTOPTS) {
   2397 		if (pktopt->ip6po_dest2)
   2398 			free(pktopt->ip6po_dest2, M_IP6OPT);
   2399 		pktopt->ip6po_dest2 = NULL;
   2400 	}
   2401 }
   2402 
   2403 #define PKTOPT_EXTHDRCPY(type) 					\
   2404 do {								\
   2405 	if (src->type) {					\
   2406 		int hlen = (((struct ip6_ext *)src->type)->ip6e_len + 1) << 3;\
   2407 		dst->type = malloc(hlen, M_IP6OPT, canwait);	\
   2408 		if (dst->type == NULL && canwait == M_NOWAIT)	\
   2409 			goto bad;				\
   2410 		memcpy(dst->type, src->type, hlen);		\
   2411 	}							\
   2412 } while (/*CONSTCOND*/ 0)
   2413 
   2414 static int
   2415 copypktopts(struct ip6_pktopts *dst, struct ip6_pktopts *src, int canwait)
   2416 {
   2417 	dst->ip6po_hlim = src->ip6po_hlim;
   2418 	dst->ip6po_tclass = src->ip6po_tclass;
   2419 	dst->ip6po_flags = src->ip6po_flags;
   2420 	if (src->ip6po_pktinfo) {
   2421 		dst->ip6po_pktinfo = malloc(sizeof(*dst->ip6po_pktinfo),
   2422 		    M_IP6OPT, canwait);
   2423 		if (dst->ip6po_pktinfo == NULL && canwait == M_NOWAIT)
   2424 			goto bad;
   2425 		*dst->ip6po_pktinfo = *src->ip6po_pktinfo;
   2426 	}
   2427 	if (src->ip6po_nexthop) {
   2428 		dst->ip6po_nexthop = malloc(src->ip6po_nexthop->sa_len,
   2429 		    M_IP6OPT, canwait);
   2430 		if (dst->ip6po_nexthop == NULL && canwait == M_NOWAIT)
   2431 			goto bad;
   2432 		memcpy(dst->ip6po_nexthop, src->ip6po_nexthop,
   2433 		    src->ip6po_nexthop->sa_len);
   2434 	}
   2435 	PKTOPT_EXTHDRCPY(ip6po_hbh);
   2436 	PKTOPT_EXTHDRCPY(ip6po_dest1);
   2437 	PKTOPT_EXTHDRCPY(ip6po_dest2);
   2438 	PKTOPT_EXTHDRCPY(ip6po_rthdr); /* not copy the cached route */
   2439 	return (0);
   2440 
   2441   bad:
   2442 	if (dst->ip6po_pktinfo) free(dst->ip6po_pktinfo, M_IP6OPT);
   2443 	if (dst->ip6po_nexthop) free(dst->ip6po_nexthop, M_IP6OPT);
   2444 	if (dst->ip6po_hbh) free(dst->ip6po_hbh, M_IP6OPT);
   2445 	if (dst->ip6po_dest1) free(dst->ip6po_dest1, M_IP6OPT);
   2446 	if (dst->ip6po_dest2) free(dst->ip6po_dest2, M_IP6OPT);
   2447 	if (dst->ip6po_rthdr) free(dst->ip6po_rthdr, M_IP6OPT);
   2448 
   2449 	return (ENOBUFS);
   2450 }
   2451 #undef PKTOPT_EXTHDRCPY
   2452 
   2453 struct ip6_pktopts *
   2454 ip6_copypktopts(struct ip6_pktopts *src, int canwait)
   2455 {
   2456 	int error;
   2457 	struct ip6_pktopts *dst;
   2458 
   2459 	dst = malloc(sizeof(*dst), M_IP6OPT, canwait);
   2460 	if (dst == NULL && canwait == M_NOWAIT)
   2461 		return (NULL);
   2462 	ip6_initpktopts(dst);
   2463 
   2464 	if ((error = copypktopts(dst, src, canwait)) != 0) {
   2465 		free(dst, M_IP6OPT);
   2466 		return (NULL);
   2467 	}
   2468 
   2469 	return (dst);
   2470 }
   2471 
   2472 void
   2473 ip6_freepcbopts(struct ip6_pktopts *pktopt)
   2474 {
   2475 	if (pktopt == NULL)
   2476 		return;
   2477 
   2478 	ip6_clearpktopts(pktopt, -1);
   2479 
   2480 	free(pktopt, M_IP6OPT);
   2481 }
   2482 
   2483 /*
   2484  * Set the IP6 multicast options in response to user setsockopt().
   2485  */
   2486 static int
   2487 ip6_setmoptions(int optname, struct ip6_moptions **im6op, struct mbuf *m)
   2488 {
   2489 	int error = 0;
   2490 	u_int loop, ifindex;
   2491 	struct ipv6_mreq *mreq;
   2492 	struct ifnet *ifp;
   2493 	struct ip6_moptions *im6o = *im6op;
   2494 	struct route ro;
   2495 	struct in6_multi_mship *imm;
   2496 	struct lwp *l = curlwp;	/* XXX */
   2497 
   2498 	if (im6o == NULL) {
   2499 		/*
   2500 		 * No multicast option buffer attached to the pcb;
   2501 		 * allocate one and initialize to default values.
   2502 		 */
   2503 		im6o = (struct ip6_moptions *)
   2504 			malloc(sizeof(*im6o), M_IPMOPTS, M_WAITOK);
   2505 
   2506 		if (im6o == NULL)
   2507 			return (ENOBUFS);
   2508 		*im6op = im6o;
   2509 		im6o->im6o_multicast_ifp = NULL;
   2510 		im6o->im6o_multicast_hlim = ip6_defmcasthlim;
   2511 		im6o->im6o_multicast_loop = IPV6_DEFAULT_MULTICAST_LOOP;
   2512 		LIST_INIT(&im6o->im6o_memberships);
   2513 	}
   2514 
   2515 	switch (optname) {
   2516 
   2517 	case IPV6_MULTICAST_IF:
   2518 		/*
   2519 		 * Select the interface for outgoing multicast packets.
   2520 		 */
   2521 		if (m == NULL || m->m_len != sizeof(u_int)) {
   2522 			error = EINVAL;
   2523 			break;
   2524 		}
   2525 		bcopy(mtod(m, u_int *), &ifindex, sizeof(ifindex));
   2526 		if (ifindex != 0) {
   2527 			if (if_indexlim <= ifindex || !ifindex2ifnet[ifindex]) {
   2528 				error = ENXIO;	/* XXX EINVAL? */
   2529 				break;
   2530 			}
   2531 			ifp = ifindex2ifnet[ifindex];
   2532 			if ((ifp->if_flags & IFF_MULTICAST) == 0) {
   2533 				error = EADDRNOTAVAIL;
   2534 				break;
   2535 			}
   2536 		} else
   2537 			ifp = NULL;
   2538 		im6o->im6o_multicast_ifp = ifp;
   2539 		break;
   2540 
   2541 	case IPV6_MULTICAST_HOPS:
   2542 	    {
   2543 		/*
   2544 		 * Set the IP6 hoplimit for outgoing multicast packets.
   2545 		 */
   2546 		int optval;
   2547 		if (m == NULL || m->m_len != sizeof(int)) {
   2548 			error = EINVAL;
   2549 			break;
   2550 		}
   2551 		bcopy(mtod(m, u_int *), &optval, sizeof(optval));
   2552 		if (optval < -1 || optval >= 256)
   2553 			error = EINVAL;
   2554 		else if (optval == -1)
   2555 			im6o->im6o_multicast_hlim = ip6_defmcasthlim;
   2556 		else
   2557 			im6o->im6o_multicast_hlim = optval;
   2558 		break;
   2559 	    }
   2560 
   2561 	case IPV6_MULTICAST_LOOP:
   2562 		/*
   2563 		 * Set the loopback flag for outgoing multicast packets.
   2564 		 * Must be zero or one.
   2565 		 */
   2566 		if (m == NULL || m->m_len != sizeof(u_int)) {
   2567 			error = EINVAL;
   2568 			break;
   2569 		}
   2570 		bcopy(mtod(m, u_int *), &loop, sizeof(loop));
   2571 		if (loop > 1) {
   2572 			error = EINVAL;
   2573 			break;
   2574 		}
   2575 		im6o->im6o_multicast_loop = loop;
   2576 		break;
   2577 
   2578 	case IPV6_JOIN_GROUP:
   2579 		/*
   2580 		 * Add a multicast group membership.
   2581 		 * Group must be a valid IP6 multicast address.
   2582 		 */
   2583 		if (m == NULL || m->m_len != sizeof(struct ipv6_mreq)) {
   2584 			error = EINVAL;
   2585 			break;
   2586 		}
   2587 		mreq = mtod(m, struct ipv6_mreq *);
   2588 		if (IN6_IS_ADDR_UNSPECIFIED(&mreq->ipv6mr_multiaddr)) {
   2589 			/*
   2590 			 * We use the unspecified address to specify to accept
   2591 			 * all multicast addresses. Only super user is allowed
   2592 			 * to do this.
   2593 			 */
   2594 			if (kauth_authorize_generic(l->l_cred,
   2595 			    KAUTH_GENERIC_ISSUSER, NULL))
   2596 			{
   2597 				error = EACCES;
   2598 				break;
   2599 			}
   2600 		} else if (!IN6_IS_ADDR_MULTICAST(&mreq->ipv6mr_multiaddr)) {
   2601 			error = EINVAL;
   2602 			break;
   2603 		}
   2604 
   2605 		/*
   2606 		 * If no interface was explicitly specified, choose an
   2607 		 * appropriate one according to the given multicast address.
   2608 		 */
   2609 		if (mreq->ipv6mr_interface == 0) {
   2610 			union {
   2611 				struct sockaddr		dst;
   2612 				struct sockaddr_in6	dst6;
   2613 			} u;
   2614 
   2615 			/*
   2616 			 * Look up the routing table for the
   2617 			 * address, and choose the outgoing interface.
   2618 			 *   XXX: is it a good approach?
   2619 			 */
   2620 			memset(&ro, 0, sizeof(ro));
   2621 			sockaddr_in6_init(&u.dst6, &mreq->ipv6mr_multiaddr, 0,
   2622 			    0, 0);
   2623 			rtcache_setdst(&ro, &u.dst);
   2624 			rtcache_init(&ro);
   2625 			ifp = (ro.ro_rt != NULL) ? ro.ro_rt->rt_ifp : NULL;
   2626 			rtcache_free(&ro);
   2627 		} else {
   2628 			/*
   2629 			 * If the interface is specified, validate it.
   2630 			 */
   2631 			if (if_indexlim <= mreq->ipv6mr_interface ||
   2632 			    !ifindex2ifnet[mreq->ipv6mr_interface]) {
   2633 				error = ENXIO;	/* XXX EINVAL? */
   2634 				break;
   2635 			}
   2636 			ifp = ifindex2ifnet[mreq->ipv6mr_interface];
   2637 		}
   2638 
   2639 		/*
   2640 		 * See if we found an interface, and confirm that it
   2641 		 * supports multicast
   2642 		 */
   2643 		if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) {
   2644 			error = EADDRNOTAVAIL;
   2645 			break;
   2646 		}
   2647 
   2648 		if (in6_setscope(&mreq->ipv6mr_multiaddr, ifp, NULL)) {
   2649 			error = EADDRNOTAVAIL; /* XXX: should not happen */
   2650 			break;
   2651 		}
   2652 
   2653 		/*
   2654 		 * See if the membership already exists.
   2655 		 */
   2656 		for (imm = im6o->im6o_memberships.lh_first;
   2657 		     imm != NULL; imm = imm->i6mm_chain.le_next)
   2658 			if (imm->i6mm_maddr->in6m_ifp == ifp &&
   2659 			    IN6_ARE_ADDR_EQUAL(&imm->i6mm_maddr->in6m_addr,
   2660 			    &mreq->ipv6mr_multiaddr))
   2661 				break;
   2662 		if (imm != NULL) {
   2663 			error = EADDRINUSE;
   2664 			break;
   2665 		}
   2666 		/*
   2667 		 * Everything looks good; add a new record to the multicast
   2668 		 * address list for the given interface.
   2669 		 */
   2670 		imm = in6_joingroup(ifp, &mreq->ipv6mr_multiaddr, &error, 0);
   2671 		if (imm == NULL)
   2672 			break;
   2673 		LIST_INSERT_HEAD(&im6o->im6o_memberships, imm, i6mm_chain);
   2674 		break;
   2675 
   2676 	case IPV6_LEAVE_GROUP:
   2677 		/*
   2678 		 * Drop a multicast group membership.
   2679 		 * Group must be a valid IP6 multicast address.
   2680 		 */
   2681 		if (m == NULL || m->m_len != sizeof(struct ipv6_mreq)) {
   2682 			error = EINVAL;
   2683 			break;
   2684 		}
   2685 		mreq = mtod(m, struct ipv6_mreq *);
   2686 
   2687 		/*
   2688 		 * If an interface address was specified, get a pointer
   2689 		 * to its ifnet structure.
   2690 		 */
   2691 		if (mreq->ipv6mr_interface != 0) {
   2692 			if (if_indexlim <= mreq->ipv6mr_interface ||
   2693 			    !ifindex2ifnet[mreq->ipv6mr_interface]) {
   2694 				error = ENXIO;	/* XXX EINVAL? */
   2695 				break;
   2696 			}
   2697 			ifp = ifindex2ifnet[mreq->ipv6mr_interface];
   2698 		} else
   2699 			ifp = NULL;
   2700 
   2701 		/* Fill in the scope zone ID */
   2702 		if (ifp) {
   2703 			if (in6_setscope(&mreq->ipv6mr_multiaddr, ifp, NULL)) {
   2704 				/* XXX: should not happen */
   2705 				error = EADDRNOTAVAIL;
   2706 				break;
   2707 			}
   2708 		} else if (mreq->ipv6mr_interface != 0) {
   2709 			/*
   2710 			 * XXX: This case would happens when the (positive)
   2711 			 * index is in the valid range, but the corresponding
   2712 			 * interface has been detached dynamically.  The above
   2713 			 * check probably avoids such case to happen here, but
   2714 			 * we check it explicitly for safety.
   2715 			 */
   2716 			error = EADDRNOTAVAIL;
   2717 			break;
   2718 		} else {	/* ipv6mr_interface == 0 */
   2719 			struct sockaddr_in6 sa6_mc;
   2720 
   2721 			/*
   2722 			 * The API spec says as follows:
   2723 			 *  If the interface index is specified as 0, the
   2724 			 *  system may choose a multicast group membership to
   2725 			 *  drop by matching the multicast address only.
   2726 			 * On the other hand, we cannot disambiguate the scope
   2727 			 * zone unless an interface is provided.  Thus, we
   2728 			 * check if there's ambiguity with the default scope
   2729 			 * zone as the last resort.
   2730 			 */
   2731 			bzero(&sa6_mc, sizeof(sa6_mc));
   2732 			sa6_mc.sin6_family = AF_INET6;
   2733 			sa6_mc.sin6_len = sizeof(sa6_mc);
   2734 			sa6_mc.sin6_addr = mreq->ipv6mr_multiaddr;
   2735 			error = sa6_embedscope(&sa6_mc, ip6_use_defzone);
   2736 			if (error != 0)
   2737 				break;
   2738 			mreq->ipv6mr_multiaddr = sa6_mc.sin6_addr;
   2739 		}
   2740 
   2741 		/*
   2742 		 * Find the membership in the membership list.
   2743 		 */
   2744 		for (imm = im6o->im6o_memberships.lh_first;
   2745 		     imm != NULL; imm = imm->i6mm_chain.le_next) {
   2746 			if ((ifp == NULL || imm->i6mm_maddr->in6m_ifp == ifp) &&
   2747 			    IN6_ARE_ADDR_EQUAL(&imm->i6mm_maddr->in6m_addr,
   2748 			    &mreq->ipv6mr_multiaddr))
   2749 				break;
   2750 		}
   2751 		if (imm == NULL) {
   2752 			/* Unable to resolve interface */
   2753 			error = EADDRNOTAVAIL;
   2754 			break;
   2755 		}
   2756 		/*
   2757 		 * Give up the multicast address record to which the
   2758 		 * membership points.
   2759 		 */
   2760 		LIST_REMOVE(imm, i6mm_chain);
   2761 		in6_leavegroup(imm);
   2762 		break;
   2763 
   2764 	default:
   2765 		error = EOPNOTSUPP;
   2766 		break;
   2767 	}
   2768 
   2769 	/*
   2770 	 * If all options have default values, no need to keep the mbuf.
   2771 	 */
   2772 	if (im6o->im6o_multicast_ifp == NULL &&
   2773 	    im6o->im6o_multicast_hlim == ip6_defmcasthlim &&
   2774 	    im6o->im6o_multicast_loop == IPV6_DEFAULT_MULTICAST_LOOP &&
   2775 	    im6o->im6o_memberships.lh_first == NULL) {
   2776 		free(*im6op, M_IPMOPTS);
   2777 		*im6op = NULL;
   2778 	}
   2779 
   2780 	return (error);
   2781 }
   2782 
   2783 /*
   2784  * Return the IP6 multicast options in response to user getsockopt().
   2785  */
   2786 static int
   2787 ip6_getmoptions(int optname, struct ip6_moptions *im6o, struct mbuf **mp)
   2788 {
   2789 	u_int *hlim, *loop, *ifindex;
   2790 
   2791 	*mp = m_get(M_WAIT, MT_SOOPTS);
   2792 
   2793 	switch (optname) {
   2794 
   2795 	case IPV6_MULTICAST_IF:
   2796 		ifindex = mtod(*mp, u_int *);
   2797 		(*mp)->m_len = sizeof(u_int);
   2798 		if (im6o == NULL || im6o->im6o_multicast_ifp == NULL)
   2799 			*ifindex = 0;
   2800 		else
   2801 			*ifindex = im6o->im6o_multicast_ifp->if_index;
   2802 		return (0);
   2803 
   2804 	case IPV6_MULTICAST_HOPS:
   2805 		hlim = mtod(*mp, u_int *);
   2806 		(*mp)->m_len = sizeof(u_int);
   2807 		if (im6o == NULL)
   2808 			*hlim = ip6_defmcasthlim;
   2809 		else
   2810 			*hlim = im6o->im6o_multicast_hlim;
   2811 		return (0);
   2812 
   2813 	case IPV6_MULTICAST_LOOP:
   2814 		loop = mtod(*mp, u_int *);
   2815 		(*mp)->m_len = sizeof(u_int);
   2816 		if (im6o == NULL)
   2817 			*loop = ip6_defmcasthlim;
   2818 		else
   2819 			*loop = im6o->im6o_multicast_loop;
   2820 		return (0);
   2821 
   2822 	default:
   2823 		return (EOPNOTSUPP);
   2824 	}
   2825 }
   2826 
   2827 /*
   2828  * Discard the IP6 multicast options.
   2829  */
   2830 void
   2831 ip6_freemoptions(struct ip6_moptions *im6o)
   2832 {
   2833 	struct in6_multi_mship *imm;
   2834 
   2835 	if (im6o == NULL)
   2836 		return;
   2837 
   2838 	while ((imm = im6o->im6o_memberships.lh_first) != NULL) {
   2839 		LIST_REMOVE(imm, i6mm_chain);
   2840 		in6_leavegroup(imm);
   2841 	}
   2842 	free(im6o, M_IPMOPTS);
   2843 }
   2844 
   2845 /*
   2846  * Set IPv6 outgoing packet options based on advanced API.
   2847  */
   2848 int
   2849 ip6_setpktopts(struct mbuf *control, struct ip6_pktopts *opt,
   2850 	struct ip6_pktopts *stickyopt, int priv, int uproto)
   2851 {
   2852 	struct cmsghdr *cm = 0;
   2853 
   2854 	if (control == NULL || opt == NULL)
   2855 		return (EINVAL);
   2856 
   2857 	ip6_initpktopts(opt);
   2858 	if (stickyopt) {
   2859 		int error;
   2860 
   2861 		/*
   2862 		 * If stickyopt is provided, make a local copy of the options
   2863 		 * for this particular packet, then override them by ancillary
   2864 		 * objects.
   2865 		 * XXX: copypktopts() does not copy the cached route to a next
   2866 		 * hop (if any).  This is not very good in terms of efficiency,
   2867 		 * but we can allow this since this option should be rarely
   2868 		 * used.
   2869 		 */
   2870 		if ((error = copypktopts(opt, stickyopt, M_NOWAIT)) != 0)
   2871 			return (error);
   2872 	}
   2873 
   2874 	/*
   2875 	 * XXX: Currently, we assume all the optional information is stored
   2876 	 * in a single mbuf.
   2877 	 */
   2878 	if (control->m_next)
   2879 		return (EINVAL);
   2880 
   2881 	for (; control->m_len; control->m_data += CMSG_ALIGN(cm->cmsg_len),
   2882 	    control->m_len -= CMSG_ALIGN(cm->cmsg_len)) {
   2883 		int error;
   2884 
   2885 		if (control->m_len < CMSG_LEN(0))
   2886 			return (EINVAL);
   2887 
   2888 		cm = mtod(control, struct cmsghdr *);
   2889 		if (cm->cmsg_len == 0 || cm->cmsg_len > control->m_len)
   2890 			return (EINVAL);
   2891 		if (cm->cmsg_level != IPPROTO_IPV6)
   2892 			continue;
   2893 
   2894 		error = ip6_setpktopt(cm->cmsg_type, CMSG_DATA(cm),
   2895 		    cm->cmsg_len - CMSG_LEN(0), opt, priv, 0, 1, uproto);
   2896 		if (error)
   2897 			return (error);
   2898 	}
   2899 
   2900 	return (0);
   2901 }
   2902 
   2903 /*
   2904  * Set a particular packet option, as a sticky option or an ancillary data
   2905  * item.  "len" can be 0 only when it's a sticky option.
   2906  * We have 4 cases of combination of "sticky" and "cmsg":
   2907  * "sticky=0, cmsg=0": impossible
   2908  * "sticky=0, cmsg=1": RFC2292 or RFC3542 ancillary data
   2909  * "sticky=1, cmsg=0": RFC3542 socket option
   2910  * "sticky=1, cmsg=1": RFC2292 socket option
   2911  */
   2912 static int
   2913 ip6_setpktopt(int optname, u_char *buf, int len, struct ip6_pktopts *opt,
   2914     int priv, int sticky, int cmsg, int uproto)
   2915 {
   2916 	int minmtupolicy;
   2917 
   2918 	if (!sticky && !cmsg) {
   2919 #ifdef DIAGNOSTIC
   2920 		printf("ip6_setpktopt: impossible case\n");
   2921 #endif
   2922 		return (EINVAL);
   2923 	}
   2924 
   2925 	/*
   2926 	 * IPV6_2292xxx is for backward compatibility to RFC2292, and should
   2927 	 * not be specified in the context of RFC3542.  Conversely,
   2928 	 * RFC3542 types should not be specified in the context of RFC2292.
   2929 	 */
   2930 	if (!cmsg) {
   2931 		switch (optname) {
   2932 		case IPV6_2292PKTINFO:
   2933 		case IPV6_2292HOPLIMIT:
   2934 		case IPV6_2292NEXTHOP:
   2935 		case IPV6_2292HOPOPTS:
   2936 		case IPV6_2292DSTOPTS:
   2937 		case IPV6_2292RTHDR:
   2938 		case IPV6_2292PKTOPTIONS:
   2939 			return (ENOPROTOOPT);
   2940 		}
   2941 	}
   2942 	if (sticky && cmsg) {
   2943 		switch (optname) {
   2944 		case IPV6_PKTINFO:
   2945 		case IPV6_HOPLIMIT:
   2946 		case IPV6_NEXTHOP:
   2947 		case IPV6_HOPOPTS:
   2948 		case IPV6_DSTOPTS:
   2949 		case IPV6_RTHDRDSTOPTS:
   2950 		case IPV6_RTHDR:
   2951 		case IPV6_USE_MIN_MTU:
   2952 		case IPV6_DONTFRAG:
   2953 		case IPV6_OTCLASS:
   2954 		case IPV6_TCLASS:
   2955 			return (ENOPROTOOPT);
   2956 		}
   2957 	}
   2958 
   2959 	switch (optname) {
   2960 #ifdef RFC2292
   2961 	case IPV6_2292PKTINFO:
   2962 #endif
   2963 	case IPV6_PKTINFO:
   2964 	{
   2965 		struct ifnet *ifp = NULL;
   2966 		struct in6_pktinfo *pktinfo;
   2967 
   2968 		if (len != sizeof(struct in6_pktinfo))
   2969 			return (EINVAL);
   2970 
   2971 		pktinfo = (struct in6_pktinfo *)buf;
   2972 
   2973 		/*
   2974 		 * An application can clear any sticky IPV6_PKTINFO option by
   2975 		 * doing a "regular" setsockopt with ipi6_addr being
   2976 		 * in6addr_any and ipi6_ifindex being zero.
   2977 		 * [RFC 3542, Section 6]
   2978 		 */
   2979 		if (optname == IPV6_PKTINFO && opt->ip6po_pktinfo &&
   2980 		    pktinfo->ipi6_ifindex == 0 &&
   2981 		    IN6_IS_ADDR_UNSPECIFIED(&pktinfo->ipi6_addr)) {
   2982 			ip6_clearpktopts(opt, optname);
   2983 			break;
   2984 		}
   2985 
   2986 		if (uproto == IPPROTO_TCP && optname == IPV6_PKTINFO &&
   2987 		    sticky && !IN6_IS_ADDR_UNSPECIFIED(&pktinfo->ipi6_addr)) {
   2988 			return (EINVAL);
   2989 		}
   2990 
   2991 		/* validate the interface index if specified. */
   2992 		if (pktinfo->ipi6_ifindex >= if_indexlim) {
   2993 			 return (ENXIO);
   2994 		}
   2995 		if (pktinfo->ipi6_ifindex) {
   2996 			ifp = ifindex2ifnet[pktinfo->ipi6_ifindex];
   2997 			if (ifp == NULL)
   2998 				return (ENXIO);
   2999 		}
   3000 
   3001 		/*
   3002 		 * We store the address anyway, and let in6_selectsrc()
   3003 		 * validate the specified address.  This is because ipi6_addr
   3004 		 * may not have enough information about its scope zone, and
   3005 		 * we may need additional information (such as outgoing
   3006 		 * interface or the scope zone of a destination address) to
   3007 		 * disambiguate the scope.
   3008 		 * XXX: the delay of the validation may confuse the
   3009 		 * application when it is used as a sticky option.
   3010 		 */
   3011 		if (opt->ip6po_pktinfo == NULL) {
   3012 			opt->ip6po_pktinfo = malloc(sizeof(*pktinfo),
   3013 			    M_IP6OPT, M_NOWAIT);
   3014 			if (opt->ip6po_pktinfo == NULL)
   3015 				return (ENOBUFS);
   3016 		}
   3017 		memcpy(opt->ip6po_pktinfo, pktinfo, sizeof(*pktinfo));
   3018 		break;
   3019 	}
   3020 
   3021 #ifdef RFC2292
   3022 	case IPV6_2292HOPLIMIT:
   3023 #endif
   3024 	case IPV6_HOPLIMIT:
   3025 	{
   3026 		int *hlimp;
   3027 
   3028 		/*
   3029 		 * RFC 3542 deprecated the usage of sticky IPV6_HOPLIMIT
   3030 		 * to simplify the ordering among hoplimit options.
   3031 		 */
   3032 		if (optname == IPV6_HOPLIMIT && sticky)
   3033 			return (ENOPROTOOPT);
   3034 
   3035 		if (len != sizeof(int))
   3036 			return (EINVAL);
   3037 		hlimp = (int *)buf;
   3038 		if (*hlimp < -1 || *hlimp > 255)
   3039 			return (EINVAL);
   3040 
   3041 		opt->ip6po_hlim = *hlimp;
   3042 		break;
   3043 	}
   3044 
   3045 	case IPV6_OTCLASS:
   3046 		if (len != sizeof(u_int8_t))
   3047 			return (EINVAL);
   3048 
   3049 		opt->ip6po_tclass = *(u_int8_t *)buf;
   3050 		break;
   3051 
   3052 	case IPV6_TCLASS:
   3053 	{
   3054 		int tclass;
   3055 
   3056 		if (len != sizeof(int))
   3057 			return (EINVAL);
   3058 		tclass = *(int *)buf;
   3059 		if (tclass < -1 || tclass > 255)
   3060 			return (EINVAL);
   3061 
   3062 		opt->ip6po_tclass = tclass;
   3063 		break;
   3064 	}
   3065 
   3066 #ifdef RFC2292
   3067 	case IPV6_2292NEXTHOP:
   3068 #endif
   3069 	case IPV6_NEXTHOP:
   3070 		if (!priv)
   3071 			return (EPERM);
   3072 
   3073 		if (len == 0) {	/* just remove the option */
   3074 			ip6_clearpktopts(opt, IPV6_NEXTHOP);
   3075 			break;
   3076 		}
   3077 
   3078 		/* check if cmsg_len is large enough for sa_len */
   3079 		if (len < sizeof(struct sockaddr) || len < *buf)
   3080 			return (EINVAL);
   3081 
   3082 		switch (((struct sockaddr *)buf)->sa_family) {
   3083 		case AF_INET6:
   3084 		{
   3085 			struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)buf;
   3086 			int error;
   3087 
   3088 			if (sa6->sin6_len != sizeof(struct sockaddr_in6))
   3089 				return (EINVAL);
   3090 
   3091 			if (IN6_IS_ADDR_UNSPECIFIED(&sa6->sin6_addr) ||
   3092 			    IN6_IS_ADDR_MULTICAST(&sa6->sin6_addr)) {
   3093 				return (EINVAL);
   3094 			}
   3095 			if ((error = sa6_embedscope(sa6, ip6_use_defzone))
   3096 			    != 0) {
   3097 				return (error);
   3098 			}
   3099 			break;
   3100 		}
   3101 		case AF_LINK:	/* eventually be supported? */
   3102 		default:
   3103 			return (EAFNOSUPPORT);
   3104 		}
   3105 
   3106 		/* turn off the previous option, then set the new option. */
   3107 		ip6_clearpktopts(opt, IPV6_NEXTHOP);
   3108 		opt->ip6po_nexthop = malloc(*buf, M_IP6OPT, M_NOWAIT);
   3109 		if (opt->ip6po_nexthop == NULL)
   3110 			return (ENOBUFS);
   3111 		memcpy(opt->ip6po_nexthop, buf, *buf);
   3112 		break;
   3113 
   3114 #ifdef RFC2292
   3115 	case IPV6_2292HOPOPTS:
   3116 #endif
   3117 	case IPV6_HOPOPTS:
   3118 	{
   3119 		struct ip6_hbh *hbh;
   3120 		int hbhlen;
   3121 
   3122 		/*
   3123 		 * XXX: We don't allow a non-privileged user to set ANY HbH
   3124 		 * options, since per-option restriction has too much
   3125 		 * overhead.
   3126 		 */
   3127 		if (!priv)
   3128 			return (EPERM);
   3129 
   3130 		if (len == 0) {
   3131 			ip6_clearpktopts(opt, IPV6_HOPOPTS);
   3132 			break;	/* just remove the option */
   3133 		}
   3134 
   3135 		/* message length validation */
   3136 		if (len < sizeof(struct ip6_hbh))
   3137 			return (EINVAL);
   3138 		hbh = (struct ip6_hbh *)buf;
   3139 		hbhlen = (hbh->ip6h_len + 1) << 3;
   3140 		if (len != hbhlen)
   3141 			return (EINVAL);
   3142 
   3143 		/* turn off the previous option, then set the new option. */
   3144 		ip6_clearpktopts(opt, IPV6_HOPOPTS);
   3145 		opt->ip6po_hbh = malloc(hbhlen, M_IP6OPT, M_NOWAIT);
   3146 		if (opt->ip6po_hbh == NULL)
   3147 			return (ENOBUFS);
   3148 		memcpy(opt->ip6po_hbh, hbh, hbhlen);
   3149 
   3150 		break;
   3151 	}
   3152 
   3153 #ifdef RFC2292
   3154 	case IPV6_2292DSTOPTS:
   3155 #endif
   3156 	case IPV6_DSTOPTS:
   3157 	case IPV6_RTHDRDSTOPTS:
   3158 	{
   3159 		struct ip6_dest *dest, **newdest = NULL;
   3160 		int destlen;
   3161 
   3162 		if (!priv)	/* XXX: see the comment for IPV6_HOPOPTS */
   3163 			return (EPERM);
   3164 
   3165 		if (len == 0) {
   3166 			ip6_clearpktopts(opt, optname);
   3167 			break;	/* just remove the option */
   3168 		}
   3169 
   3170 		/* message length validation */
   3171 		if (len < sizeof(struct ip6_dest))
   3172 			return (EINVAL);
   3173 		dest = (struct ip6_dest *)buf;
   3174 		destlen = (dest->ip6d_len + 1) << 3;
   3175 		if (len != destlen)
   3176 			return (EINVAL);
   3177 		/*
   3178 		 * Determine the position that the destination options header
   3179 		 * should be inserted; before or after the routing header.
   3180 		 */
   3181 		switch (optname) {
   3182 		case IPV6_2292DSTOPTS:
   3183 			/*
   3184 			 * The old advanced API is ambiguous on this point.
   3185 			 * Our approach is to determine the position based
   3186 			 * according to the existence of a routing header.
   3187 			 * Note, however, that this depends on the order of the
   3188 			 * extension headers in the ancillary data; the 1st
   3189 			 * part of the destination options header must appear
   3190 			 * before the routing header in the ancillary data,
   3191 			 * too.
   3192 			 * RFC3542 solved the ambiguity by introducing
   3193 			 * separate ancillary data or option types.
   3194 			 */
   3195 			if (opt->ip6po_rthdr == NULL)
   3196 				newdest = &opt->ip6po_dest1;
   3197 			else
   3198 				newdest = &opt->ip6po_dest2;
   3199 			break;
   3200 		case IPV6_RTHDRDSTOPTS:
   3201 			newdest = &opt->ip6po_dest1;
   3202 			break;
   3203 		case IPV6_DSTOPTS:
   3204 			newdest = &opt->ip6po_dest2;
   3205 			break;
   3206 		}
   3207 
   3208 		/* turn off the previous option, then set the new option. */
   3209 		ip6_clearpktopts(opt, optname);
   3210 		*newdest = malloc(destlen, M_IP6OPT, M_NOWAIT);
   3211 		if (*newdest == NULL)
   3212 			return (ENOBUFS);
   3213 		memcpy(*newdest, dest, destlen);
   3214 
   3215 		break;
   3216 	}
   3217 
   3218 #ifdef RFC2292
   3219 	case IPV6_2292RTHDR:
   3220 #endif
   3221 	case IPV6_RTHDR:
   3222 	{
   3223 		struct ip6_rthdr *rth;
   3224 		int rthlen;
   3225 
   3226 		if (len == 0) {
   3227 			ip6_clearpktopts(opt, IPV6_RTHDR);
   3228 			break;	/* just remove the option */
   3229 		}
   3230 
   3231 		/* message length validation */
   3232 		if (len < sizeof(struct ip6_rthdr))
   3233 			return (EINVAL);
   3234 		rth = (struct ip6_rthdr *)buf;
   3235 		rthlen = (rth->ip6r_len + 1) << 3;
   3236 		if (len != rthlen)
   3237 			return (EINVAL);
   3238 		switch (rth->ip6r_type) {
   3239 		case IPV6_RTHDR_TYPE_0:
   3240 			if (rth->ip6r_len == 0)	/* must contain one addr */
   3241 				return (EINVAL);
   3242 			if (rth->ip6r_len % 2) /* length must be even */
   3243 				return (EINVAL);
   3244 			if (rth->ip6r_len / 2 != rth->ip6r_segleft)
   3245 				return (EINVAL);
   3246 			break;
   3247 		default:
   3248 			return (EINVAL);	/* not supported */
   3249 		}
   3250 		/* turn off the previous option */
   3251 		ip6_clearpktopts(opt, IPV6_RTHDR);
   3252 		opt->ip6po_rthdr = malloc(rthlen, M_IP6OPT, M_NOWAIT);
   3253 		if (opt->ip6po_rthdr == NULL)
   3254 			return (ENOBUFS);
   3255 		memcpy(opt->ip6po_rthdr, rth, rthlen);
   3256 		break;
   3257 	}
   3258 
   3259 	case IPV6_USE_MIN_MTU:
   3260 		if (len != sizeof(int))
   3261 			return (EINVAL);
   3262 		minmtupolicy = *(int *)buf;
   3263 		if (minmtupolicy != IP6PO_MINMTU_MCASTONLY &&
   3264 		    minmtupolicy != IP6PO_MINMTU_DISABLE &&
   3265 		    minmtupolicy != IP6PO_MINMTU_ALL) {
   3266 			return (EINVAL);
   3267 		}
   3268 		opt->ip6po_minmtu = minmtupolicy;
   3269 		break;
   3270 
   3271 	case IPV6_DONTFRAG:
   3272 		if (len != sizeof(int))
   3273 			return (EINVAL);
   3274 
   3275 		if (uproto == IPPROTO_TCP || *(int *)buf == 0) {
   3276 			/*
   3277 			 * we ignore this option for TCP sockets.
   3278 			 * (RFC3542 leaves this case unspecified.)
   3279 			 */
   3280 			opt->ip6po_flags &= ~IP6PO_DONTFRAG;
   3281 		} else
   3282 			opt->ip6po_flags |= IP6PO_DONTFRAG;
   3283 		break;
   3284 
   3285 	default:
   3286 		return (ENOPROTOOPT);
   3287 	} /* end of switch */
   3288 
   3289 	return (0);
   3290 }
   3291 
   3292 /*
   3293  * Routine called from ip6_output() to loop back a copy of an IP6 multicast
   3294  * packet to the input queue of a specified interface.  Note that this
   3295  * calls the output routine of the loopback "driver", but with an interface
   3296  * pointer that might NOT be lo0ifp -- easier than replicating that code here.
   3297  */
   3298 void
   3299 ip6_mloopback(struct ifnet *ifp, struct mbuf *m,
   3300 	const struct sockaddr_in6 *dst)
   3301 {
   3302 	struct mbuf *copym;
   3303 	struct ip6_hdr *ip6;
   3304 
   3305 	copym = m_copy(m, 0, M_COPYALL);
   3306 	if (copym == NULL)
   3307 		return;
   3308 
   3309 	/*
   3310 	 * Make sure to deep-copy IPv6 header portion in case the data
   3311 	 * is in an mbuf cluster, so that we can safely override the IPv6
   3312 	 * header portion later.
   3313 	 */
   3314 	if ((copym->m_flags & M_EXT) != 0 ||
   3315 	    copym->m_len < sizeof(struct ip6_hdr)) {
   3316 		copym = m_pullup(copym, sizeof(struct ip6_hdr));
   3317 		if (copym == NULL)
   3318 			return;
   3319 	}
   3320 
   3321 #ifdef DIAGNOSTIC
   3322 	if (copym->m_len < sizeof(*ip6)) {
   3323 		m_freem(copym);
   3324 		return;
   3325 	}
   3326 #endif
   3327 
   3328 	ip6 = mtod(copym, struct ip6_hdr *);
   3329 	/*
   3330 	 * clear embedded scope identifiers if necessary.
   3331 	 * in6_clearscope will touch the addresses only when necessary.
   3332 	 */
   3333 	in6_clearscope(&ip6->ip6_src);
   3334 	in6_clearscope(&ip6->ip6_dst);
   3335 
   3336 	(void)looutput(ifp, copym, (const struct sockaddr *)dst, NULL);
   3337 }
   3338 
   3339 /*
   3340  * Chop IPv6 header off from the payload.
   3341  */
   3342 static int
   3343 ip6_splithdr(struct mbuf *m,  struct ip6_exthdrs *exthdrs)
   3344 {
   3345 	struct mbuf *mh;
   3346 	struct ip6_hdr *ip6;
   3347 
   3348 	ip6 = mtod(m, struct ip6_hdr *);
   3349 	if (m->m_len > sizeof(*ip6)) {
   3350 		MGETHDR(mh, M_DONTWAIT, MT_HEADER);
   3351 		if (mh == 0) {
   3352 			m_freem(m);
   3353 			return ENOBUFS;
   3354 		}
   3355 		M_MOVE_PKTHDR(mh, m);
   3356 		MH_ALIGN(mh, sizeof(*ip6));
   3357 		m->m_len -= sizeof(*ip6);
   3358 		m->m_data += sizeof(*ip6);
   3359 		mh->m_next = m;
   3360 		m = mh;
   3361 		m->m_len = sizeof(*ip6);
   3362 		bcopy((void *)ip6, mtod(m, void *), sizeof(*ip6));
   3363 	}
   3364 	exthdrs->ip6e_ip6 = m;
   3365 	return 0;
   3366 }
   3367 
   3368 /*
   3369  * Compute IPv6 extension header length.
   3370  */
   3371 int
   3372 ip6_optlen(struct in6pcb *in6p)
   3373 {
   3374 	int len;
   3375 
   3376 	if (!in6p->in6p_outputopts)
   3377 		return 0;
   3378 
   3379 	len = 0;
   3380 #define elen(x) \
   3381     (((struct ip6_ext *)(x)) ? (((struct ip6_ext *)(x))->ip6e_len + 1) << 3 : 0)
   3382 
   3383 	len += elen(in6p->in6p_outputopts->ip6po_hbh);
   3384 	len += elen(in6p->in6p_outputopts->ip6po_dest1);
   3385 	len += elen(in6p->in6p_outputopts->ip6po_rthdr);
   3386 	len += elen(in6p->in6p_outputopts->ip6po_dest2);
   3387 	return len;
   3388 #undef elen
   3389 }
   3390