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ip6_output.c revision 1.160.2.5
      1 /*	$NetBSD: ip6_output.c,v 1.160.2.5 2016/10/05 20:56:09 skrll 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 1.160.2.5 2016/10/05 20:56:09 skrll Exp $");
     66 
     67 #ifdef _KERNEL_OPT
     68 #include "opt_inet.h"
     69 #include "opt_inet6.h"
     70 #include "opt_ipsec.h"
     71 #endif
     72 
     73 #include <sys/param.h>
     74 #include <sys/malloc.h>
     75 #include <sys/mbuf.h>
     76 #include <sys/errno.h>
     77 #include <sys/protosw.h>
     78 #include <sys/socket.h>
     79 #include <sys/socketvar.h>
     80 #include <sys/syslog.h>
     81 #include <sys/systm.h>
     82 #include <sys/proc.h>
     83 #include <sys/kauth.h>
     84 
     85 #include <net/if.h>
     86 #include <net/route.h>
     87 #include <net/pfil.h>
     88 
     89 #include <netinet/in.h>
     90 #include <netinet/in_var.h>
     91 #include <netinet/ip6.h>
     92 #include <netinet/ip_var.h>
     93 #include <netinet/icmp6.h>
     94 #include <netinet/in_offload.h>
     95 #include <netinet/portalgo.h>
     96 #include <netinet6/in6_offload.h>
     97 #include <netinet6/ip6_var.h>
     98 #include <netinet6/ip6_private.h>
     99 #include <netinet6/in6_pcb.h>
    100 #include <netinet6/nd6.h>
    101 #include <netinet6/ip6protosw.h>
    102 #include <netinet6/scope6_var.h>
    103 
    104 #ifdef IPSEC
    105 #include <netipsec/ipsec.h>
    106 #include <netipsec/ipsec6.h>
    107 #include <netipsec/key.h>
    108 #include <netipsec/xform.h>
    109 #endif
    110 
    111 
    112 #include <net/net_osdep.h>
    113 
    114 extern pfil_head_t *inet6_pfil_hook;	/* XXX */
    115 
    116 struct ip6_exthdrs {
    117 	struct mbuf *ip6e_ip6;
    118 	struct mbuf *ip6e_hbh;
    119 	struct mbuf *ip6e_dest1;
    120 	struct mbuf *ip6e_rthdr;
    121 	struct mbuf *ip6e_dest2;
    122 };
    123 
    124 static int ip6_pcbopt(int, u_char *, int, struct ip6_pktopts **,
    125 	kauth_cred_t, int);
    126 static int ip6_getpcbopt(struct ip6_pktopts *, int, struct sockopt *);
    127 static int ip6_setpktopt(int, u_char *, int, struct ip6_pktopts *, kauth_cred_t,
    128 	int, int, int);
    129 static int ip6_setmoptions(const struct sockopt *, struct in6pcb *);
    130 static int ip6_getmoptions(struct sockopt *, struct in6pcb *);
    131 static int ip6_copyexthdr(struct mbuf **, void *, int);
    132 static int ip6_insertfraghdr(struct mbuf *, struct mbuf *, int,
    133 	struct ip6_frag **);
    134 static int ip6_insert_jumboopt(struct ip6_exthdrs *, u_int32_t);
    135 static int ip6_splithdr(struct mbuf *, struct ip6_exthdrs *);
    136 static int ip6_getpmtu(struct route *, struct route *, struct ifnet *,
    137     const struct in6_addr *, u_long *, int *);
    138 static int copypktopts(struct ip6_pktopts *, struct ip6_pktopts *, int);
    139 static int ip6_ifaddrvalid(const struct in6_addr *);
    140 
    141 #ifdef RFC2292
    142 static int ip6_pcbopts(struct ip6_pktopts **, struct socket *, struct sockopt *);
    143 #endif
    144 
    145 /*
    146  * IP6 output. The packet in mbuf chain m contains a skeletal IP6
    147  * header (with pri, len, nxt, hlim, src, dst).
    148  * This function may modify ver and hlim only.
    149  * The mbuf chain containing the packet will be freed.
    150  * The mbuf opt, if present, will not be freed.
    151  *
    152  * type of "mtu": rt_rmx.rmx_mtu is u_long, ifnet.ifr_mtu is int, and
    153  * nd_ifinfo.linkmtu is u_int32_t.  so we use u_long to hold largest one,
    154  * which is rt_rmx.rmx_mtu.
    155  */
    156 int
    157 ip6_output(
    158     struct mbuf *m0,
    159     struct ip6_pktopts *opt,
    160     struct route *ro,
    161     int flags,
    162     struct ip6_moptions *im6o,
    163     struct socket *so,
    164     struct ifnet **ifpp		/* XXX: just for statistics */
    165 )
    166 {
    167 	struct ip6_hdr *ip6, *mhip6;
    168 	struct ifnet *ifp = NULL, *origifp = NULL;
    169 	struct mbuf *m = m0;
    170 	int hlen, tlen, len, off;
    171 	bool tso;
    172 	struct route ip6route;
    173 	struct rtentry *rt = NULL;
    174 	const struct sockaddr_in6 *dst;
    175 	struct sockaddr_in6 src_sa, dst_sa;
    176 	int error = 0;
    177 	struct in6_ifaddr *ia = NULL;
    178 	u_long mtu;
    179 	int alwaysfrag, dontfrag;
    180 	u_int32_t optlen = 0, plen = 0, unfragpartlen = 0;
    181 	struct ip6_exthdrs exthdrs;
    182 	struct in6_addr finaldst, src0, dst0;
    183 	u_int32_t zone;
    184 	struct route *ro_pmtu = NULL;
    185 	int hdrsplit = 0;
    186 	int needipsec = 0;
    187 #ifdef IPSEC
    188 	struct secpolicy *sp = NULL;
    189 #endif
    190 	struct psref psref, psref_ia;
    191 	int bound = curlwp_bind();
    192 	bool release_psref_ia = false;
    193 
    194 #ifdef  DIAGNOSTIC
    195 	if ((m->m_flags & M_PKTHDR) == 0)
    196 		panic("ip6_output: no HDR");
    197 
    198 	if ((m->m_pkthdr.csum_flags &
    199 	    (M_CSUM_TCPv4|M_CSUM_UDPv4|M_CSUM_TSOv4)) != 0) {
    200 		panic("ip6_output: IPv4 checksum offload flags: %d",
    201 		    m->m_pkthdr.csum_flags);
    202 	}
    203 
    204 	if ((m->m_pkthdr.csum_flags & (M_CSUM_TCPv6|M_CSUM_UDPv6)) ==
    205 	    (M_CSUM_TCPv6|M_CSUM_UDPv6)) {
    206 		panic("ip6_output: conflicting checksum offload flags: %d",
    207 		    m->m_pkthdr.csum_flags);
    208 	}
    209 #endif
    210 
    211 	M_CSUM_DATA_IPv6_HL_SET(m->m_pkthdr.csum_data, sizeof(struct ip6_hdr));
    212 
    213 #define MAKE_EXTHDR(hp, mp)						\
    214     do {								\
    215 	if (hp) {							\
    216 		struct ip6_ext *eh = (struct ip6_ext *)(hp);		\
    217 		error = ip6_copyexthdr((mp), (void *)(hp), 		\
    218 		    ((eh)->ip6e_len + 1) << 3);				\
    219 		if (error)						\
    220 			goto freehdrs;					\
    221 	}								\
    222     } while (/*CONSTCOND*/ 0)
    223 
    224 	memset(&exthdrs, 0, sizeof(exthdrs));
    225 	if (opt) {
    226 		/* Hop-by-Hop options header */
    227 		MAKE_EXTHDR(opt->ip6po_hbh, &exthdrs.ip6e_hbh);
    228 		/* Destination options header(1st part) */
    229 		MAKE_EXTHDR(opt->ip6po_dest1, &exthdrs.ip6e_dest1);
    230 		/* Routing header */
    231 		MAKE_EXTHDR(opt->ip6po_rthdr, &exthdrs.ip6e_rthdr);
    232 		/* Destination options header(2nd part) */
    233 		MAKE_EXTHDR(opt->ip6po_dest2, &exthdrs.ip6e_dest2);
    234 	}
    235 
    236 	/*
    237 	 * Calculate the total length of the extension header chain.
    238 	 * Keep the length of the unfragmentable part for fragmentation.
    239 	 */
    240 	optlen = 0;
    241 	if (exthdrs.ip6e_hbh) optlen += exthdrs.ip6e_hbh->m_len;
    242 	if (exthdrs.ip6e_dest1) optlen += exthdrs.ip6e_dest1->m_len;
    243 	if (exthdrs.ip6e_rthdr) optlen += exthdrs.ip6e_rthdr->m_len;
    244 	unfragpartlen = optlen + sizeof(struct ip6_hdr);
    245 	/* NOTE: we don't add AH/ESP length here. do that later. */
    246 	if (exthdrs.ip6e_dest2) optlen += exthdrs.ip6e_dest2->m_len;
    247 
    248 #ifdef IPSEC
    249 	if (ipsec_used) {
    250 		/* Check the security policy (SP) for the packet */
    251 
    252 		sp = ipsec6_check_policy(m, so, flags, &needipsec, &error);
    253 		if (error != 0) {
    254 			/*
    255 			 * Hack: -EINVAL is used to signal that a packet
    256 			 * should be silently discarded.  This is typically
    257 			 * because we asked key management for an SA and
    258 			 * it was delayed (e.g. kicked up to IKE).
    259 			 */
    260 			if (error == -EINVAL)
    261 				error = 0;
    262 			goto freehdrs;
    263 		}
    264 	}
    265 #endif /* IPSEC */
    266 
    267 
    268 	if (needipsec &&
    269 	    (m->m_pkthdr.csum_flags & (M_CSUM_UDPv6|M_CSUM_TCPv6)) != 0) {
    270 		in6_delayed_cksum(m);
    271 		m->m_pkthdr.csum_flags &= ~(M_CSUM_UDPv6|M_CSUM_TCPv6);
    272 	}
    273 
    274 
    275 	/*
    276 	 * If we need IPsec, or there is at least one extension header,
    277 	 * separate IP6 header from the payload.
    278 	 */
    279 	if ((needipsec || optlen) && !hdrsplit) {
    280 		if ((error = ip6_splithdr(m, &exthdrs)) != 0) {
    281 			m = NULL;
    282 			goto freehdrs;
    283 		}
    284 		m = exthdrs.ip6e_ip6;
    285 		hdrsplit++;
    286 	}
    287 
    288 	/* adjust pointer */
    289 	ip6 = mtod(m, struct ip6_hdr *);
    290 
    291 	/* adjust mbuf packet header length */
    292 	m->m_pkthdr.len += optlen;
    293 	plen = m->m_pkthdr.len - sizeof(*ip6);
    294 
    295 	/* If this is a jumbo payload, insert a jumbo payload option. */
    296 	if (plen > IPV6_MAXPACKET) {
    297 		if (!hdrsplit) {
    298 			if ((error = ip6_splithdr(m, &exthdrs)) != 0) {
    299 				m = NULL;
    300 				goto freehdrs;
    301 			}
    302 			m = exthdrs.ip6e_ip6;
    303 			hdrsplit++;
    304 		}
    305 		/* adjust pointer */
    306 		ip6 = mtod(m, struct ip6_hdr *);
    307 		if ((error = ip6_insert_jumboopt(&exthdrs, plen)) != 0)
    308 			goto freehdrs;
    309 		optlen += 8; /* XXX JUMBOOPTLEN */
    310 		ip6->ip6_plen = 0;
    311 	} else
    312 		ip6->ip6_plen = htons(plen);
    313 
    314 	/*
    315 	 * Concatenate headers and fill in next header fields.
    316 	 * Here we have, on "m"
    317 	 *	IPv6 payload
    318 	 * and we insert headers accordingly.  Finally, we should be getting:
    319 	 *	IPv6 hbh dest1 rthdr ah* [esp* dest2 payload]
    320 	 *
    321 	 * during the header composing process, "m" points to IPv6 header.
    322 	 * "mprev" points to an extension header prior to esp.
    323 	 */
    324 	{
    325 		u_char *nexthdrp = &ip6->ip6_nxt;
    326 		struct mbuf *mprev = m;
    327 
    328 		/*
    329 		 * we treat dest2 specially.  this makes IPsec processing
    330 		 * much easier.  the goal here is to make mprev point the
    331 		 * mbuf prior to dest2.
    332 		 *
    333 		 * result: IPv6 dest2 payload
    334 		 * m and mprev will point to IPv6 header.
    335 		 */
    336 		if (exthdrs.ip6e_dest2) {
    337 			if (!hdrsplit)
    338 				panic("assumption failed: hdr not split");
    339 			exthdrs.ip6e_dest2->m_next = m->m_next;
    340 			m->m_next = exthdrs.ip6e_dest2;
    341 			*mtod(exthdrs.ip6e_dest2, u_char *) = ip6->ip6_nxt;
    342 			ip6->ip6_nxt = IPPROTO_DSTOPTS;
    343 		}
    344 
    345 #define MAKE_CHAIN(m, mp, p, i)\
    346     do {\
    347 	if (m) {\
    348 		if (!hdrsplit) \
    349 			panic("assumption failed: hdr not split"); \
    350 		*mtod((m), u_char *) = *(p);\
    351 		*(p) = (i);\
    352 		p = mtod((m), u_char *);\
    353 		(m)->m_next = (mp)->m_next;\
    354 		(mp)->m_next = (m);\
    355 		(mp) = (m);\
    356 	}\
    357     } while (/*CONSTCOND*/ 0)
    358 		/*
    359 		 * result: IPv6 hbh dest1 rthdr dest2 payload
    360 		 * m will point to IPv6 header.  mprev will point to the
    361 		 * extension header prior to dest2 (rthdr in the above case).
    362 		 */
    363 		MAKE_CHAIN(exthdrs.ip6e_hbh, mprev, nexthdrp, IPPROTO_HOPOPTS);
    364 		MAKE_CHAIN(exthdrs.ip6e_dest1, mprev, nexthdrp,
    365 		    IPPROTO_DSTOPTS);
    366 		MAKE_CHAIN(exthdrs.ip6e_rthdr, mprev, nexthdrp,
    367 		    IPPROTO_ROUTING);
    368 
    369 		M_CSUM_DATA_IPv6_HL_SET(m->m_pkthdr.csum_data,
    370 		    sizeof(struct ip6_hdr) + optlen);
    371 	}
    372 
    373 	/*
    374 	 * If there is a routing header, replace destination address field
    375 	 * with the first hop of the routing header.
    376 	 */
    377 	if (exthdrs.ip6e_rthdr) {
    378 		struct ip6_rthdr *rh;
    379 		struct ip6_rthdr0 *rh0;
    380 		struct in6_addr *addr;
    381 		struct sockaddr_in6 sa;
    382 
    383 		rh = (struct ip6_rthdr *)(mtod(exthdrs.ip6e_rthdr,
    384 		    struct ip6_rthdr *));
    385 		finaldst = ip6->ip6_dst;
    386 		switch (rh->ip6r_type) {
    387 		case IPV6_RTHDR_TYPE_0:
    388 			 rh0 = (struct ip6_rthdr0 *)rh;
    389 			 addr = (struct in6_addr *)(rh0 + 1);
    390 
    391 			 /*
    392 			  * construct a sockaddr_in6 form of
    393 			  * the first hop.
    394 			  *
    395 			  * XXX: we may not have enough
    396 			  * information about its scope zone;
    397 			  * there is no standard API to pass
    398 			  * the information from the
    399 			  * application.
    400 			  */
    401 			 sockaddr_in6_init(&sa, addr, 0, 0, 0);
    402 			 if ((error = sa6_embedscope(&sa,
    403 			     ip6_use_defzone)) != 0) {
    404 				 goto bad;
    405 			 }
    406 			 ip6->ip6_dst = sa.sin6_addr;
    407 			 (void)memmove(&addr[0], &addr[1],
    408 			     sizeof(struct in6_addr) *
    409 			     (rh0->ip6r0_segleft - 1));
    410 			 addr[rh0->ip6r0_segleft - 1] = finaldst;
    411 			 /* XXX */
    412 			 in6_clearscope(addr + rh0->ip6r0_segleft - 1);
    413 			 break;
    414 		default:	/* is it possible? */
    415 			 error = EINVAL;
    416 			 goto bad;
    417 		}
    418 	}
    419 
    420 	/* Source address validation */
    421 	if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) &&
    422 	    (flags & IPV6_UNSPECSRC) == 0) {
    423 		error = EOPNOTSUPP;
    424 		IP6_STATINC(IP6_STAT_BADSCOPE);
    425 		goto bad;
    426 	}
    427 	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_src)) {
    428 		error = EOPNOTSUPP;
    429 		IP6_STATINC(IP6_STAT_BADSCOPE);
    430 		goto bad;
    431 	}
    432 
    433 	IP6_STATINC(IP6_STAT_LOCALOUT);
    434 
    435 	/*
    436 	 * Route packet.
    437 	 */
    438 	/* initialize cached route */
    439 	if (ro == NULL) {
    440 		memset(&ip6route, 0, sizeof(ip6route));
    441 		ro = &ip6route;
    442 	}
    443 	ro_pmtu = ro;
    444 	if (opt && opt->ip6po_rthdr)
    445 		ro = &opt->ip6po_route;
    446 
    447  	/*
    448 	 * if specified, try to fill in the traffic class field.
    449 	 * do not override if a non-zero value is already set.
    450 	 * we check the diffserv field and the ecn field separately.
    451 	 */
    452 	if (opt && opt->ip6po_tclass >= 0) {
    453 		int mask = 0;
    454 
    455 		if ((ip6->ip6_flow & htonl(0xfc << 20)) == 0)
    456 			mask |= 0xfc;
    457 		if ((ip6->ip6_flow & htonl(0x03 << 20)) == 0)
    458 			mask |= 0x03;
    459 		if (mask != 0)
    460 			ip6->ip6_flow |= htonl((opt->ip6po_tclass & mask) << 20);
    461 	}
    462 
    463 	/* fill in or override the hop limit field, if necessary. */
    464 	if (opt && opt->ip6po_hlim != -1)
    465 		ip6->ip6_hlim = opt->ip6po_hlim & 0xff;
    466 	else if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
    467 		if (im6o != NULL)
    468 			ip6->ip6_hlim = im6o->im6o_multicast_hlim;
    469 		else
    470 			ip6->ip6_hlim = ip6_defmcasthlim;
    471 	}
    472 
    473 #ifdef IPSEC
    474 	if (needipsec) {
    475 		int s = splsoftnet();
    476 		error = ipsec6_process_packet(m, sp->req);
    477 
    478 		/*
    479 		 * Preserve KAME behaviour: ENOENT can be returned
    480 		 * when an SA acquire is in progress.  Don't propagate
    481 		 * this to user-level; it confuses applications.
    482 		 * XXX this will go away when the SADB is redone.
    483 		 */
    484 		if (error == ENOENT)
    485 			error = 0;
    486 		splx(s);
    487 		goto done;
    488 	}
    489 #endif /* IPSEC */
    490 
    491 	/* adjust pointer */
    492 	ip6 = mtod(m, struct ip6_hdr *);
    493 
    494 	sockaddr_in6_init(&dst_sa, &ip6->ip6_dst, 0, 0, 0);
    495 	if ((error = in6_selectroute(&dst_sa, opt, im6o, ro,
    496 	    &ifp, &psref, &rt, 0)) != 0) {
    497 		if (ifp != NULL)
    498 			in6_ifstat_inc(ifp, ifs6_out_discard);
    499 		goto bad;
    500 	}
    501 	if (rt == NULL) {
    502 		/*
    503 		 * If in6_selectroute() does not return a route entry,
    504 		 * dst may not have been updated.
    505 		 */
    506 		error = rtcache_setdst(ro, sin6tosa(&dst_sa));
    507 		if (error) {
    508 			goto bad;
    509 		}
    510 	}
    511 
    512 	/*
    513 	 * then rt (for unicast) and ifp must be non-NULL valid values.
    514 	 */
    515 	if ((flags & IPV6_FORWARDING) == 0) {
    516 		/* XXX: the FORWARDING flag can be set for mrouting. */
    517 		in6_ifstat_inc(ifp, ifs6_out_request);
    518 	}
    519 	if (rt != NULL) {
    520 		ia = (struct in6_ifaddr *)(rt->rt_ifa);
    521 		rt->rt_use++;
    522 	}
    523 
    524 	/*
    525 	 * The outgoing interface must be in the zone of source and
    526 	 * destination addresses.  We should use ia_ifp to support the
    527 	 * case of sending packets to an address of our own.
    528 	 */
    529 	if (ia != NULL && ia->ia_ifp) {
    530 		origifp = ia->ia_ifp;
    531 		if (if_is_deactivated(origifp))
    532 			goto bad;
    533 		if_acquire_NOMPSAFE(origifp, &psref_ia);
    534 		release_psref_ia = true;
    535 	} else
    536 		origifp = ifp;
    537 
    538 	src0 = ip6->ip6_src;
    539 	if (in6_setscope(&src0, origifp, &zone))
    540 		goto badscope;
    541 	sockaddr_in6_init(&src_sa, &ip6->ip6_src, 0, 0, 0);
    542 	if (sa6_recoverscope(&src_sa) || zone != src_sa.sin6_scope_id)
    543 		goto badscope;
    544 
    545 	dst0 = ip6->ip6_dst;
    546 	if (in6_setscope(&dst0, origifp, &zone))
    547 		goto badscope;
    548 	/* re-initialize to be sure */
    549 	sockaddr_in6_init(&dst_sa, &ip6->ip6_dst, 0, 0, 0);
    550 	if (sa6_recoverscope(&dst_sa) || zone != dst_sa.sin6_scope_id)
    551 		goto badscope;
    552 
    553 	/* scope check is done. */
    554 
    555 	/* Ensure we only send from a valid address. */
    556 	if ((error = ip6_ifaddrvalid(&src0)) != 0) {
    557 		nd6log(LOG_ERR,
    558 		    "refusing to send from invalid address %s (pid %d)\n",
    559 		    ip6_sprintf(&src0), curproc->p_pid);
    560 		IP6_STATINC(IP6_STAT_ODROPPED);
    561 		in6_ifstat_inc(origifp, ifs6_out_discard);
    562 		if (error == 1)
    563 			/*
    564 			 * Address exists, but is tentative or detached.
    565 			 * We can't send from it because it's invalid,
    566 			 * so we drop the packet.
    567 			 */
    568 			error = 0;
    569 		else
    570 			error = EADDRNOTAVAIL;
    571 		goto bad;
    572 	}
    573 
    574 	if (rt == NULL || IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
    575 		dst = satocsin6(rtcache_getdst(ro));
    576 		KASSERT(dst != NULL);
    577 	} else if (opt && rtcache_validate(&opt->ip6po_nextroute) != NULL) {
    578 		/*
    579 		 * The nexthop is explicitly specified by the
    580 		 * application.  We assume the next hop is an IPv6
    581 		 * address.
    582 		 */
    583 		dst = (struct sockaddr_in6 *)opt->ip6po_nexthop;
    584 	} else if ((rt->rt_flags & RTF_GATEWAY))
    585 		dst = (struct sockaddr_in6 *)rt->rt_gateway;
    586 	else
    587 		dst = satocsin6(rtcache_getdst(ro));
    588 
    589 	/*
    590 	 * XXXXXX: original code follows:
    591 	 */
    592 	if (!IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst))
    593 		m->m_flags &= ~(M_BCAST | M_MCAST);	/* just in case */
    594 	else {
    595 		struct	in6_multi *in6m;
    596 
    597 		m->m_flags = (m->m_flags & ~M_BCAST) | M_MCAST;
    598 
    599 		in6_ifstat_inc(ifp, ifs6_out_mcast);
    600 
    601 		/*
    602 		 * Confirm that the outgoing interface supports multicast.
    603 		 */
    604 		if (!(ifp->if_flags & IFF_MULTICAST)) {
    605 			IP6_STATINC(IP6_STAT_NOROUTE);
    606 			in6_ifstat_inc(ifp, ifs6_out_discard);
    607 			error = ENETUNREACH;
    608 			goto bad;
    609 		}
    610 
    611 		IN6_LOOKUP_MULTI(ip6->ip6_dst, ifp, in6m);
    612 		if (in6m != NULL &&
    613 		   (im6o == NULL || im6o->im6o_multicast_loop)) {
    614 			/*
    615 			 * If we belong to the destination multicast group
    616 			 * on the outgoing interface, and the caller did not
    617 			 * forbid loopback, loop back a copy.
    618 			 */
    619 			KASSERT(dst != NULL);
    620 			ip6_mloopback(ifp, m, dst);
    621 		} else {
    622 			/*
    623 			 * If we are acting as a multicast router, perform
    624 			 * multicast forwarding as if the packet had just
    625 			 * arrived on the interface to which we are about
    626 			 * to send.  The multicast forwarding function
    627 			 * recursively calls this function, using the
    628 			 * IPV6_FORWARDING flag to prevent infinite recursion.
    629 			 *
    630 			 * Multicasts that are looped back by ip6_mloopback(),
    631 			 * above, will be forwarded by the ip6_input() routine,
    632 			 * if necessary.
    633 			 */
    634 			if (ip6_mrouter && (flags & IPV6_FORWARDING) == 0) {
    635 				if (ip6_mforward(ip6, ifp, m) != 0) {
    636 					m_freem(m);
    637 					goto done;
    638 				}
    639 			}
    640 		}
    641 		/*
    642 		 * Multicasts with a hoplimit of zero may be looped back,
    643 		 * above, but must not be transmitted on a network.
    644 		 * Also, multicasts addressed to the loopback interface
    645 		 * are not sent -- the above call to ip6_mloopback() will
    646 		 * loop back a copy if this host actually belongs to the
    647 		 * destination group on the loopback interface.
    648 		 */
    649 		if (ip6->ip6_hlim == 0 || (ifp->if_flags & IFF_LOOPBACK) ||
    650 		    IN6_IS_ADDR_MC_INTFACELOCAL(&ip6->ip6_dst)) {
    651 			m_freem(m);
    652 			goto done;
    653 		}
    654 	}
    655 
    656 	/*
    657 	 * Fill the outgoing inteface to tell the upper layer
    658 	 * to increment per-interface statistics.
    659 	 */
    660 	if (ifpp)
    661 		*ifpp = ifp;
    662 
    663 	/* Determine path MTU. */
    664 	if ((error = ip6_getpmtu(ro_pmtu, ro, ifp, &finaldst, &mtu,
    665 	    &alwaysfrag)) != 0)
    666 		goto bad;
    667 
    668 	/*
    669 	 * The caller of this function may specify to use the minimum MTU
    670 	 * in some cases.
    671 	 * An advanced API option (IPV6_USE_MIN_MTU) can also override MTU
    672 	 * setting.  The logic is a bit complicated; by default, unicast
    673 	 * packets will follow path MTU while multicast packets will be sent at
    674 	 * the minimum MTU.  If IP6PO_MINMTU_ALL is specified, all packets
    675 	 * including unicast ones will be sent at the minimum MTU.  Multicast
    676 	 * packets will always be sent at the minimum MTU unless
    677 	 * IP6PO_MINMTU_DISABLE is explicitly specified.
    678 	 * See RFC 3542 for more details.
    679 	 */
    680 	if (mtu > IPV6_MMTU) {
    681 		if ((flags & IPV6_MINMTU))
    682 			mtu = IPV6_MMTU;
    683 		else if (opt && opt->ip6po_minmtu == IP6PO_MINMTU_ALL)
    684 			mtu = IPV6_MMTU;
    685 		else if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) &&
    686 			 (opt == NULL ||
    687 			  opt->ip6po_minmtu != IP6PO_MINMTU_DISABLE)) {
    688 			mtu = IPV6_MMTU;
    689 		}
    690 	}
    691 
    692 	/*
    693 	 * clear embedded scope identifiers if necessary.
    694 	 * in6_clearscope will touch the addresses only when necessary.
    695 	 */
    696 	in6_clearscope(&ip6->ip6_src);
    697 	in6_clearscope(&ip6->ip6_dst);
    698 
    699 	/*
    700 	 * If the outgoing packet contains a hop-by-hop options header,
    701 	 * it must be examined and processed even by the source node.
    702 	 * (RFC 2460, section 4.)
    703 	 */
    704 	if (ip6->ip6_nxt == IPV6_HOPOPTS) {
    705 		u_int32_t dummy1; /* XXX unused */
    706 		u_int32_t dummy2; /* XXX unused */
    707 		int hoff = sizeof(struct ip6_hdr);
    708 
    709 		if (ip6_hopopts_input(&dummy1, &dummy2, &m, &hoff)) {
    710 			/* m was already freed at this point */
    711 			error = EINVAL;/* better error? */
    712 			goto done;
    713 		}
    714 
    715 		ip6 = mtod(m, struct ip6_hdr *);
    716 	}
    717 
    718 	/*
    719 	 * Run through list of hooks for output packets.
    720 	 */
    721 	if ((error = pfil_run_hooks(inet6_pfil_hook, &m, ifp, PFIL_OUT)) != 0)
    722 		goto done;
    723 	if (m == NULL)
    724 		goto done;
    725 	ip6 = mtod(m, struct ip6_hdr *);
    726 
    727 	/*
    728 	 * Send the packet to the outgoing interface.
    729 	 * If necessary, do IPv6 fragmentation before sending.
    730 	 *
    731 	 * the logic here is rather complex:
    732 	 * 1: normal case (dontfrag == 0, alwaysfrag == 0)
    733 	 * 1-a:	send as is if tlen <= path mtu
    734 	 * 1-b:	fragment if tlen > path mtu
    735 	 *
    736 	 * 2: if user asks us not to fragment (dontfrag == 1)
    737 	 * 2-a:	send as is if tlen <= interface mtu
    738 	 * 2-b:	error if tlen > interface mtu
    739 	 *
    740 	 * 3: if we always need to attach fragment header (alwaysfrag == 1)
    741 	 *	always fragment
    742 	 *
    743 	 * 4: if dontfrag == 1 && alwaysfrag == 1
    744 	 *	error, as we cannot handle this conflicting request
    745 	 */
    746 	tlen = m->m_pkthdr.len;
    747 	tso = (m->m_pkthdr.csum_flags & M_CSUM_TSOv6) != 0;
    748 	if (opt && (opt->ip6po_flags & IP6PO_DONTFRAG))
    749 		dontfrag = 1;
    750 	else
    751 		dontfrag = 0;
    752 
    753 	if (dontfrag && alwaysfrag) {	/* case 4 */
    754 		/* conflicting request - can't transmit */
    755 		error = EMSGSIZE;
    756 		goto bad;
    757 	}
    758 	if (dontfrag && (!tso && tlen > IN6_LINKMTU(ifp))) {	/* case 2-b */
    759 		/*
    760 		 * Even if the DONTFRAG option is specified, we cannot send the
    761 		 * packet when the data length is larger than the MTU of the
    762 		 * outgoing interface.
    763 		 * Notify the error by sending IPV6_PATHMTU ancillary data as
    764 		 * well as returning an error code (the latter is not described
    765 		 * in the API spec.)
    766 		 */
    767 		u_int32_t mtu32;
    768 		struct ip6ctlparam ip6cp;
    769 
    770 		mtu32 = (u_int32_t)mtu;
    771 		memset(&ip6cp, 0, sizeof(ip6cp));
    772 		ip6cp.ip6c_cmdarg = (void *)&mtu32;
    773 		pfctlinput2(PRC_MSGSIZE,
    774 		    rtcache_getdst(ro_pmtu), &ip6cp);
    775 
    776 		error = EMSGSIZE;
    777 		goto bad;
    778 	}
    779 
    780 	/*
    781 	 * transmit packet without fragmentation
    782 	 */
    783 	if (dontfrag || (!alwaysfrag && (tlen <= mtu || tso))) {
    784 		/* case 1-a and 2-a */
    785 		struct in6_ifaddr *ia6;
    786 		int sw_csum;
    787 		int s;
    788 
    789 		ip6 = mtod(m, struct ip6_hdr *);
    790 		s = pserialize_read_enter();
    791 		ia6 = in6_ifawithifp(ifp, &ip6->ip6_src);
    792 		if (ia6) {
    793 			/* Record statistics for this interface address. */
    794 			ia6->ia_ifa.ifa_data.ifad_outbytes += m->m_pkthdr.len;
    795 		}
    796 		pserialize_read_exit(s);
    797 
    798 		sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_csum_flags_tx;
    799 		if ((sw_csum & (M_CSUM_UDPv6|M_CSUM_TCPv6)) != 0) {
    800 			if (IN6_NEED_CHECKSUM(ifp,
    801 			    sw_csum & (M_CSUM_UDPv6|M_CSUM_TCPv6))) {
    802 				in6_delayed_cksum(m);
    803 			}
    804 			m->m_pkthdr.csum_flags &= ~(M_CSUM_UDPv6|M_CSUM_TCPv6);
    805 		}
    806 
    807 		KASSERT(dst != NULL);
    808 		if (__predict_true(!tso ||
    809 		    (ifp->if_capenable & IFCAP_TSOv6) != 0)) {
    810 			error = nd6_output(ifp, origifp, m, dst, rt);
    811 		} else {
    812 			error = ip6_tso_output(ifp, origifp, m, dst, rt);
    813 		}
    814 		goto done;
    815 	}
    816 
    817 	if (tso) {
    818 		error = EINVAL; /* XXX */
    819 		goto bad;
    820 	}
    821 
    822 	/*
    823 	 * try to fragment the packet.  case 1-b and 3
    824 	 */
    825 	if (mtu < IPV6_MMTU) {
    826 		/* path MTU cannot be less than IPV6_MMTU */
    827 		error = EMSGSIZE;
    828 		in6_ifstat_inc(ifp, ifs6_out_fragfail);
    829 		goto bad;
    830 	} else if (ip6->ip6_plen == 0) {
    831 		/* jumbo payload cannot be fragmented */
    832 		error = EMSGSIZE;
    833 		in6_ifstat_inc(ifp, ifs6_out_fragfail);
    834 		goto bad;
    835 	} else {
    836 		struct mbuf **mnext, *m_frgpart;
    837 		struct ip6_frag *ip6f;
    838 		u_int32_t id = htonl(ip6_randomid());
    839 		u_char nextproto;
    840 #if 0				/* see below */
    841 		struct ip6ctlparam ip6cp;
    842 		u_int32_t mtu32;
    843 #endif
    844 
    845 		/*
    846 		 * Too large for the destination or interface;
    847 		 * fragment if possible.
    848 		 * Must be able to put at least 8 bytes per fragment.
    849 		 */
    850 		hlen = unfragpartlen;
    851 		if (mtu > IPV6_MAXPACKET)
    852 			mtu = IPV6_MAXPACKET;
    853 
    854 #if 0
    855 		/*
    856 		 * It is believed this code is a leftover from the
    857 		 * development of the IPV6_RECVPATHMTU sockopt and
    858 		 * associated work to implement RFC3542.
    859 		 * It's not entirely clear what the intent of the API
    860 		 * is at this point, so disable this code for now.
    861 		 * The IPV6_RECVPATHMTU sockopt and/or IPV6_DONTFRAG
    862 		 * will send notifications if the application requests.
    863 		 */
    864 
    865 		/* Notify a proper path MTU to applications. */
    866 		mtu32 = (u_int32_t)mtu;
    867 		memset(&ip6cp, 0, sizeof(ip6cp));
    868 		ip6cp.ip6c_cmdarg = (void *)&mtu32;
    869 		pfctlinput2(PRC_MSGSIZE,
    870 		    rtcache_getdst(ro_pmtu), &ip6cp);
    871 #endif
    872 
    873 		len = (mtu - hlen - sizeof(struct ip6_frag)) & ~7;
    874 		if (len < 8) {
    875 			error = EMSGSIZE;
    876 			in6_ifstat_inc(ifp, ifs6_out_fragfail);
    877 			goto bad;
    878 		}
    879 
    880 		mnext = &m->m_nextpkt;
    881 
    882 		/*
    883 		 * Change the next header field of the last header in the
    884 		 * unfragmentable part.
    885 		 */
    886 		if (exthdrs.ip6e_rthdr) {
    887 			nextproto = *mtod(exthdrs.ip6e_rthdr, u_char *);
    888 			*mtod(exthdrs.ip6e_rthdr, u_char *) = IPPROTO_FRAGMENT;
    889 		} else if (exthdrs.ip6e_dest1) {
    890 			nextproto = *mtod(exthdrs.ip6e_dest1, u_char *);
    891 			*mtod(exthdrs.ip6e_dest1, u_char *) = IPPROTO_FRAGMENT;
    892 		} else if (exthdrs.ip6e_hbh) {
    893 			nextproto = *mtod(exthdrs.ip6e_hbh, u_char *);
    894 			*mtod(exthdrs.ip6e_hbh, u_char *) = IPPROTO_FRAGMENT;
    895 		} else {
    896 			nextproto = ip6->ip6_nxt;
    897 			ip6->ip6_nxt = IPPROTO_FRAGMENT;
    898 		}
    899 
    900 		if ((m->m_pkthdr.csum_flags & (M_CSUM_UDPv6|M_CSUM_TCPv6))
    901 		    != 0) {
    902 			if (IN6_NEED_CHECKSUM(ifp,
    903 			    m->m_pkthdr.csum_flags &
    904 			    (M_CSUM_UDPv6|M_CSUM_TCPv6))) {
    905 				in6_delayed_cksum(m);
    906 			}
    907 			m->m_pkthdr.csum_flags &= ~(M_CSUM_UDPv6|M_CSUM_TCPv6);
    908 		}
    909 
    910 		/*
    911 		 * Loop through length of segment after first fragment,
    912 		 * make new header and copy data of each part and link onto
    913 		 * chain.
    914 		 */
    915 		m0 = m;
    916 		for (off = hlen; off < tlen; off += len) {
    917 			struct mbuf *mlast;
    918 
    919 			MGETHDR(m, M_DONTWAIT, MT_HEADER);
    920 			if (!m) {
    921 				error = ENOBUFS;
    922 				IP6_STATINC(IP6_STAT_ODROPPED);
    923 				goto sendorfree;
    924 			}
    925 			m_reset_rcvif(m);
    926 			m->m_flags = m0->m_flags & M_COPYFLAGS;
    927 			*mnext = m;
    928 			mnext = &m->m_nextpkt;
    929 			m->m_data += max_linkhdr;
    930 			mhip6 = mtod(m, struct ip6_hdr *);
    931 			*mhip6 = *ip6;
    932 			m->m_len = sizeof(*mhip6);
    933 			/*
    934 			 * ip6f must be valid if error is 0.  But how
    935 			 * can a compiler be expected to infer this?
    936 			 */
    937 			ip6f = NULL;
    938 			error = ip6_insertfraghdr(m0, m, hlen, &ip6f);
    939 			if (error) {
    940 				IP6_STATINC(IP6_STAT_ODROPPED);
    941 				goto sendorfree;
    942 			}
    943 			ip6f->ip6f_offlg = htons((u_int16_t)((off - hlen) & ~7));
    944 			if (off + len >= tlen)
    945 				len = tlen - off;
    946 			else
    947 				ip6f->ip6f_offlg |= IP6F_MORE_FRAG;
    948 			mhip6->ip6_plen = htons((u_int16_t)(len + hlen +
    949 			    sizeof(*ip6f) - sizeof(struct ip6_hdr)));
    950 			if ((m_frgpart = m_copy(m0, off, len)) == 0) {
    951 				error = ENOBUFS;
    952 				IP6_STATINC(IP6_STAT_ODROPPED);
    953 				goto sendorfree;
    954 			}
    955 			for (mlast = m; mlast->m_next; mlast = mlast->m_next)
    956 				;
    957 			mlast->m_next = m_frgpart;
    958 			m->m_pkthdr.len = len + hlen + sizeof(*ip6f);
    959 			m_reset_rcvif(m);
    960 			ip6f->ip6f_reserved = 0;
    961 			ip6f->ip6f_ident = id;
    962 			ip6f->ip6f_nxt = nextproto;
    963 			IP6_STATINC(IP6_STAT_OFRAGMENTS);
    964 			in6_ifstat_inc(ifp, ifs6_out_fragcreat);
    965 		}
    966 
    967 		in6_ifstat_inc(ifp, ifs6_out_fragok);
    968 	}
    969 
    970 	/*
    971 	 * Remove leading garbages.
    972 	 */
    973 sendorfree:
    974 	m = m0->m_nextpkt;
    975 	m0->m_nextpkt = 0;
    976 	m_freem(m0);
    977 	for (m0 = m; m; m = m0) {
    978 		m0 = m->m_nextpkt;
    979 		m->m_nextpkt = 0;
    980 		if (error == 0) {
    981 			struct in6_ifaddr *ia6;
    982 			int s;
    983 			ip6 = mtod(m, struct ip6_hdr *);
    984 			s = pserialize_read_enter();
    985 			ia6 = in6_ifawithifp(ifp, &ip6->ip6_src);
    986 			if (ia6) {
    987 				/*
    988 				 * Record statistics for this interface
    989 				 * address.
    990 				 */
    991 				ia6->ia_ifa.ifa_data.ifad_outbytes +=
    992 				    m->m_pkthdr.len;
    993 			}
    994 			pserialize_read_exit(s);
    995 			KASSERT(dst != NULL);
    996 			error = nd6_output(ifp, origifp, m, dst, rt);
    997 		} else
    998 			m_freem(m);
    999 	}
   1000 
   1001 	if (error == 0)
   1002 		IP6_STATINC(IP6_STAT_FRAGMENTED);
   1003 
   1004 done:
   1005 	if (ro == &ip6route)
   1006 		rtcache_free(&ip6route);
   1007 
   1008 #ifdef IPSEC
   1009 	if (sp != NULL)
   1010 		KEY_FREESP(&sp);
   1011 #endif /* IPSEC */
   1012 
   1013 	if_put(ifp, &psref);
   1014 	if (release_psref_ia)
   1015 		if_put(origifp, &psref_ia);
   1016 	curlwp_bindx(bound);
   1017 
   1018 	return (error);
   1019 
   1020 freehdrs:
   1021 	m_freem(exthdrs.ip6e_hbh);	/* m_freem will check if mbuf is 0 */
   1022 	m_freem(exthdrs.ip6e_dest1);
   1023 	m_freem(exthdrs.ip6e_rthdr);
   1024 	m_freem(exthdrs.ip6e_dest2);
   1025 	/* FALLTHROUGH */
   1026 bad:
   1027 	m_freem(m);
   1028 	goto done;
   1029 badscope:
   1030 	IP6_STATINC(IP6_STAT_BADSCOPE);
   1031 	in6_ifstat_inc(origifp, ifs6_out_discard);
   1032 	if (error == 0)
   1033 		error = EHOSTUNREACH; /* XXX */
   1034 	goto bad;
   1035 }
   1036 
   1037 static int
   1038 ip6_copyexthdr(struct mbuf **mp, void *hdr, int hlen)
   1039 {
   1040 	struct mbuf *m;
   1041 
   1042 	if (hlen > MCLBYTES)
   1043 		return (ENOBUFS); /* XXX */
   1044 
   1045 	MGET(m, M_DONTWAIT, MT_DATA);
   1046 	if (!m)
   1047 		return (ENOBUFS);
   1048 
   1049 	if (hlen > MLEN) {
   1050 		MCLGET(m, M_DONTWAIT);
   1051 		if ((m->m_flags & M_EXT) == 0) {
   1052 			m_free(m);
   1053 			return (ENOBUFS);
   1054 		}
   1055 	}
   1056 	m->m_len = hlen;
   1057 	if (hdr)
   1058 		bcopy(hdr, mtod(m, void *), hlen);
   1059 
   1060 	*mp = m;
   1061 	return (0);
   1062 }
   1063 
   1064 /*
   1065  * Process a delayed payload checksum calculation.
   1066  */
   1067 void
   1068 in6_delayed_cksum(struct mbuf *m)
   1069 {
   1070 	uint16_t csum, offset;
   1071 
   1072 	KASSERT((m->m_pkthdr.csum_flags & (M_CSUM_UDPv6|M_CSUM_TCPv6)) != 0);
   1073 	KASSERT((~m->m_pkthdr.csum_flags & (M_CSUM_UDPv6|M_CSUM_TCPv6)) != 0);
   1074 	KASSERT((m->m_pkthdr.csum_flags
   1075 	    & (M_CSUM_UDPv4|M_CSUM_TCPv4|M_CSUM_TSOv4)) == 0);
   1076 
   1077 	offset = M_CSUM_DATA_IPv6_HL(m->m_pkthdr.csum_data);
   1078 	csum = in6_cksum(m, 0, offset, m->m_pkthdr.len - offset);
   1079 	if (csum == 0 && (m->m_pkthdr.csum_flags & M_CSUM_UDPv6) != 0) {
   1080 		csum = 0xffff;
   1081 	}
   1082 
   1083 	offset += M_CSUM_DATA_IPv6_OFFSET(m->m_pkthdr.csum_data);
   1084 	if ((offset + sizeof(csum)) > m->m_len) {
   1085 		m_copyback(m, offset, sizeof(csum), &csum);
   1086 	} else {
   1087 		*(uint16_t *)(mtod(m, char *) + offset) = csum;
   1088 	}
   1089 }
   1090 
   1091 /*
   1092  * Insert jumbo payload option.
   1093  */
   1094 static int
   1095 ip6_insert_jumboopt(struct ip6_exthdrs *exthdrs, u_int32_t plen)
   1096 {
   1097 	struct mbuf *mopt;
   1098 	u_int8_t *optbuf;
   1099 	u_int32_t v;
   1100 
   1101 #define JUMBOOPTLEN	8	/* length of jumbo payload option and padding */
   1102 
   1103 	/*
   1104 	 * If there is no hop-by-hop options header, allocate new one.
   1105 	 * If there is one but it doesn't have enough space to store the
   1106 	 * jumbo payload option, allocate a cluster to store the whole options.
   1107 	 * Otherwise, use it to store the options.
   1108 	 */
   1109 	if (exthdrs->ip6e_hbh == 0) {
   1110 		MGET(mopt, M_DONTWAIT, MT_DATA);
   1111 		if (mopt == 0)
   1112 			return (ENOBUFS);
   1113 		mopt->m_len = JUMBOOPTLEN;
   1114 		optbuf = mtod(mopt, u_int8_t *);
   1115 		optbuf[1] = 0;	/* = ((JUMBOOPTLEN) >> 3) - 1 */
   1116 		exthdrs->ip6e_hbh = mopt;
   1117 	} else {
   1118 		struct ip6_hbh *hbh;
   1119 
   1120 		mopt = exthdrs->ip6e_hbh;
   1121 		if (M_TRAILINGSPACE(mopt) < JUMBOOPTLEN) {
   1122 			/*
   1123 			 * XXX assumption:
   1124 			 * - exthdrs->ip6e_hbh is not referenced from places
   1125 			 *   other than exthdrs.
   1126 			 * - exthdrs->ip6e_hbh is not an mbuf chain.
   1127 			 */
   1128 			int oldoptlen = mopt->m_len;
   1129 			struct mbuf *n;
   1130 
   1131 			/*
   1132 			 * XXX: give up if the whole (new) hbh header does
   1133 			 * not fit even in an mbuf cluster.
   1134 			 */
   1135 			if (oldoptlen + JUMBOOPTLEN > MCLBYTES)
   1136 				return (ENOBUFS);
   1137 
   1138 			/*
   1139 			 * As a consequence, we must always prepare a cluster
   1140 			 * at this point.
   1141 			 */
   1142 			MGET(n, M_DONTWAIT, MT_DATA);
   1143 			if (n) {
   1144 				MCLGET(n, M_DONTWAIT);
   1145 				if ((n->m_flags & M_EXT) == 0) {
   1146 					m_freem(n);
   1147 					n = NULL;
   1148 				}
   1149 			}
   1150 			if (!n)
   1151 				return (ENOBUFS);
   1152 			n->m_len = oldoptlen + JUMBOOPTLEN;
   1153 			bcopy(mtod(mopt, void *), mtod(n, void *),
   1154 			    oldoptlen);
   1155 			optbuf = mtod(n, u_int8_t *) + oldoptlen;
   1156 			m_freem(mopt);
   1157 			mopt = exthdrs->ip6e_hbh = n;
   1158 		} else {
   1159 			optbuf = mtod(mopt, u_int8_t *) + mopt->m_len;
   1160 			mopt->m_len += JUMBOOPTLEN;
   1161 		}
   1162 		optbuf[0] = IP6OPT_PADN;
   1163 		optbuf[1] = 0;
   1164 
   1165 		/*
   1166 		 * Adjust the header length according to the pad and
   1167 		 * the jumbo payload option.
   1168 		 */
   1169 		hbh = mtod(mopt, struct ip6_hbh *);
   1170 		hbh->ip6h_len += (JUMBOOPTLEN >> 3);
   1171 	}
   1172 
   1173 	/* fill in the option. */
   1174 	optbuf[2] = IP6OPT_JUMBO;
   1175 	optbuf[3] = 4;
   1176 	v = (u_int32_t)htonl(plen + JUMBOOPTLEN);
   1177 	bcopy(&v, &optbuf[4], sizeof(u_int32_t));
   1178 
   1179 	/* finally, adjust the packet header length */
   1180 	exthdrs->ip6e_ip6->m_pkthdr.len += JUMBOOPTLEN;
   1181 
   1182 	return (0);
   1183 #undef JUMBOOPTLEN
   1184 }
   1185 
   1186 /*
   1187  * Insert fragment header and copy unfragmentable header portions.
   1188  *
   1189  * *frghdrp will not be read, and it is guaranteed that either an
   1190  * error is returned or that *frghdrp will point to space allocated
   1191  * for the fragment header.
   1192  */
   1193 static int
   1194 ip6_insertfraghdr(struct mbuf *m0, struct mbuf *m, int hlen,
   1195 	struct ip6_frag **frghdrp)
   1196 {
   1197 	struct mbuf *n, *mlast;
   1198 
   1199 	if (hlen > sizeof(struct ip6_hdr)) {
   1200 		n = m_copym(m0, sizeof(struct ip6_hdr),
   1201 		    hlen - sizeof(struct ip6_hdr), M_DONTWAIT);
   1202 		if (n == 0)
   1203 			return (ENOBUFS);
   1204 		m->m_next = n;
   1205 	} else
   1206 		n = m;
   1207 
   1208 	/* Search for the last mbuf of unfragmentable part. */
   1209 	for (mlast = n; mlast->m_next; mlast = mlast->m_next)
   1210 		;
   1211 
   1212 	if ((mlast->m_flags & M_EXT) == 0 &&
   1213 	    M_TRAILINGSPACE(mlast) >= sizeof(struct ip6_frag)) {
   1214 		/* use the trailing space of the last mbuf for the fragment hdr */
   1215 		*frghdrp = (struct ip6_frag *)(mtod(mlast, char *) +
   1216 		    mlast->m_len);
   1217 		mlast->m_len += sizeof(struct ip6_frag);
   1218 		m->m_pkthdr.len += sizeof(struct ip6_frag);
   1219 	} else {
   1220 		/* allocate a new mbuf for the fragment header */
   1221 		struct mbuf *mfrg;
   1222 
   1223 		MGET(mfrg, M_DONTWAIT, MT_DATA);
   1224 		if (mfrg == 0)
   1225 			return (ENOBUFS);
   1226 		mfrg->m_len = sizeof(struct ip6_frag);
   1227 		*frghdrp = mtod(mfrg, struct ip6_frag *);
   1228 		mlast->m_next = mfrg;
   1229 	}
   1230 
   1231 	return (0);
   1232 }
   1233 
   1234 static int
   1235 ip6_getpmtu(struct route *ro_pmtu, struct route *ro, struct ifnet *ifp,
   1236     const struct in6_addr *dst, u_long *mtup, int *alwaysfragp)
   1237 {
   1238 	struct rtentry *rt;
   1239 	u_int32_t mtu = 0;
   1240 	int alwaysfrag = 0;
   1241 	int error = 0;
   1242 
   1243 	if (ro_pmtu != ro) {
   1244 		union {
   1245 			struct sockaddr		dst;
   1246 			struct sockaddr_in6	dst6;
   1247 		} u;
   1248 
   1249 		/* The first hop and the final destination may differ. */
   1250 		sockaddr_in6_init(&u.dst6, dst, 0, 0, 0);
   1251 		rt = rtcache_lookup(ro_pmtu, &u.dst);
   1252 	} else
   1253 		rt = rtcache_validate(ro_pmtu);
   1254 	if (rt != NULL) {
   1255 		u_int32_t ifmtu;
   1256 
   1257 		if (ifp == NULL)
   1258 			ifp = rt->rt_ifp;
   1259 		ifmtu = IN6_LINKMTU(ifp);
   1260 		mtu = rt->rt_rmx.rmx_mtu;
   1261 		if (mtu == 0)
   1262 			mtu = ifmtu;
   1263 		else if (mtu < IPV6_MMTU) {
   1264 			/*
   1265 			 * RFC2460 section 5, last paragraph:
   1266 			 * if we record ICMPv6 too big message with
   1267 			 * mtu < IPV6_MMTU, transmit packets sized IPV6_MMTU
   1268 			 * or smaller, with fragment header attached.
   1269 			 * (fragment header is needed regardless from the
   1270 			 * packet size, for translators to identify packets)
   1271 			 */
   1272 			alwaysfrag = 1;
   1273 			mtu = IPV6_MMTU;
   1274 		} else if (mtu > ifmtu) {
   1275 			/*
   1276 			 * The MTU on the route is larger than the MTU on
   1277 			 * the interface!  This shouldn't happen, unless the
   1278 			 * MTU of the interface has been changed after the
   1279 			 * interface was brought up.  Change the MTU in the
   1280 			 * route to match the interface MTU (as long as the
   1281 			 * field isn't locked).
   1282 			 */
   1283 			mtu = ifmtu;
   1284 			if (!(rt->rt_rmx.rmx_locks & RTV_MTU))
   1285 				rt->rt_rmx.rmx_mtu = mtu;
   1286 		}
   1287 	} else if (ifp) {
   1288 		mtu = IN6_LINKMTU(ifp);
   1289 	} else
   1290 		error = EHOSTUNREACH; /* XXX */
   1291 
   1292 	*mtup = mtu;
   1293 	if (alwaysfragp)
   1294 		*alwaysfragp = alwaysfrag;
   1295 	return (error);
   1296 }
   1297 
   1298 /*
   1299  * IP6 socket option processing.
   1300  */
   1301 int
   1302 ip6_ctloutput(int op, struct socket *so, struct sockopt *sopt)
   1303 {
   1304 	int optdatalen, uproto;
   1305 	void *optdata;
   1306 	struct in6pcb *in6p = sotoin6pcb(so);
   1307 	struct ip_moptions **mopts;
   1308 	int error, optval;
   1309 	int level, optname;
   1310 
   1311 	KASSERT(sopt != NULL);
   1312 
   1313 	level = sopt->sopt_level;
   1314 	optname = sopt->sopt_name;
   1315 
   1316 	error = optval = 0;
   1317 	uproto = (int)so->so_proto->pr_protocol;
   1318 
   1319 	switch (level) {
   1320 	case IPPROTO_IP:
   1321 		switch (optname) {
   1322 		case IP_ADD_MEMBERSHIP:
   1323 		case IP_DROP_MEMBERSHIP:
   1324 		case IP_MULTICAST_IF:
   1325 		case IP_MULTICAST_LOOP:
   1326 		case IP_MULTICAST_TTL:
   1327 			mopts = &in6p->in6p_v4moptions;
   1328 			switch (op) {
   1329 			case PRCO_GETOPT:
   1330 				return ip_getmoptions(*mopts, sopt);
   1331 			case PRCO_SETOPT:
   1332 				return ip_setmoptions(mopts, sopt);
   1333 			default:
   1334 				return EINVAL;
   1335 			}
   1336 		default:
   1337 			return ENOPROTOOPT;
   1338 		}
   1339 	case IPPROTO_IPV6:
   1340 		break;
   1341 	default:
   1342 		return ENOPROTOOPT;
   1343 	}
   1344 	switch (op) {
   1345 	case PRCO_SETOPT:
   1346 		switch (optname) {
   1347 #ifdef RFC2292
   1348 		case IPV6_2292PKTOPTIONS:
   1349 			error = ip6_pcbopts(&in6p->in6p_outputopts, so, sopt);
   1350 			break;
   1351 #endif
   1352 
   1353 		/*
   1354 		 * Use of some Hop-by-Hop options or some
   1355 		 * Destination options, might require special
   1356 		 * privilege.  That is, normal applications
   1357 		 * (without special privilege) might be forbidden
   1358 		 * from setting certain options in outgoing packets,
   1359 		 * and might never see certain options in received
   1360 		 * packets. [RFC 2292 Section 6]
   1361 		 * KAME specific note:
   1362 		 *  KAME prevents non-privileged users from sending or
   1363 		 *  receiving ANY hbh/dst options in order to avoid
   1364 		 *  overhead of parsing options in the kernel.
   1365 		 */
   1366 		case IPV6_RECVHOPOPTS:
   1367 		case IPV6_RECVDSTOPTS:
   1368 		case IPV6_RECVRTHDRDSTOPTS:
   1369 			error = kauth_authorize_network(kauth_cred_get(),
   1370 			    KAUTH_NETWORK_IPV6, KAUTH_REQ_NETWORK_IPV6_HOPBYHOP,
   1371 			    NULL, NULL, NULL);
   1372 			if (error)
   1373 				break;
   1374 			/* FALLTHROUGH */
   1375 		case IPV6_UNICAST_HOPS:
   1376 		case IPV6_HOPLIMIT:
   1377 		case IPV6_FAITH:
   1378 
   1379 		case IPV6_RECVPKTINFO:
   1380 		case IPV6_RECVHOPLIMIT:
   1381 		case IPV6_RECVRTHDR:
   1382 		case IPV6_RECVPATHMTU:
   1383 		case IPV6_RECVTCLASS:
   1384 		case IPV6_V6ONLY:
   1385 			error = sockopt_getint(sopt, &optval);
   1386 			if (error)
   1387 				break;
   1388 			switch (optname) {
   1389 			case IPV6_UNICAST_HOPS:
   1390 				if (optval < -1 || optval >= 256)
   1391 					error = EINVAL;
   1392 				else {
   1393 					/* -1 = kernel default */
   1394 					in6p->in6p_hops = optval;
   1395 				}
   1396 				break;
   1397 #define OPTSET(bit) \
   1398 do { \
   1399 if (optval) \
   1400 	in6p->in6p_flags |= (bit); \
   1401 else \
   1402 	in6p->in6p_flags &= ~(bit); \
   1403 } while (/*CONSTCOND*/ 0)
   1404 
   1405 #ifdef RFC2292
   1406 #define OPTSET2292(bit) 			\
   1407 do { 						\
   1408 in6p->in6p_flags |= IN6P_RFC2292; 	\
   1409 if (optval) 				\
   1410 	in6p->in6p_flags |= (bit); 	\
   1411 else 					\
   1412 	in6p->in6p_flags &= ~(bit); 	\
   1413 } while (/*CONSTCOND*/ 0)
   1414 #endif
   1415 
   1416 #define OPTBIT(bit) (in6p->in6p_flags & (bit) ? 1 : 0)
   1417 
   1418 			case IPV6_RECVPKTINFO:
   1419 #ifdef RFC2292
   1420 				/* cannot mix with RFC2292 */
   1421 				if (OPTBIT(IN6P_RFC2292)) {
   1422 					error = EINVAL;
   1423 					break;
   1424 				}
   1425 #endif
   1426 				OPTSET(IN6P_PKTINFO);
   1427 				break;
   1428 
   1429 			case IPV6_HOPLIMIT:
   1430 			{
   1431 				struct ip6_pktopts **optp;
   1432 
   1433 #ifdef RFC2292
   1434 				/* cannot mix with RFC2292 */
   1435 				if (OPTBIT(IN6P_RFC2292)) {
   1436 					error = EINVAL;
   1437 					break;
   1438 				}
   1439 #endif
   1440 				optp = &in6p->in6p_outputopts;
   1441 				error = ip6_pcbopt(IPV6_HOPLIMIT,
   1442 						   (u_char *)&optval,
   1443 						   sizeof(optval),
   1444 						   optp,
   1445 						   kauth_cred_get(), uproto);
   1446 				break;
   1447 			}
   1448 
   1449 			case IPV6_RECVHOPLIMIT:
   1450 #ifdef RFC2292
   1451 				/* cannot mix with RFC2292 */
   1452 				if (OPTBIT(IN6P_RFC2292)) {
   1453 					error = EINVAL;
   1454 					break;
   1455 				}
   1456 #endif
   1457 				OPTSET(IN6P_HOPLIMIT);
   1458 				break;
   1459 
   1460 			case IPV6_RECVHOPOPTS:
   1461 #ifdef RFC2292
   1462 				/* cannot mix with RFC2292 */
   1463 				if (OPTBIT(IN6P_RFC2292)) {
   1464 					error = EINVAL;
   1465 					break;
   1466 				}
   1467 #endif
   1468 				OPTSET(IN6P_HOPOPTS);
   1469 				break;
   1470 
   1471 			case IPV6_RECVDSTOPTS:
   1472 #ifdef RFC2292
   1473 				/* cannot mix with RFC2292 */
   1474 				if (OPTBIT(IN6P_RFC2292)) {
   1475 					error = EINVAL;
   1476 					break;
   1477 				}
   1478 #endif
   1479 				OPTSET(IN6P_DSTOPTS);
   1480 				break;
   1481 
   1482 			case IPV6_RECVRTHDRDSTOPTS:
   1483 #ifdef RFC2292
   1484 				/* cannot mix with RFC2292 */
   1485 				if (OPTBIT(IN6P_RFC2292)) {
   1486 					error = EINVAL;
   1487 					break;
   1488 				}
   1489 #endif
   1490 				OPTSET(IN6P_RTHDRDSTOPTS);
   1491 				break;
   1492 
   1493 			case IPV6_RECVRTHDR:
   1494 #ifdef RFC2292
   1495 				/* cannot mix with RFC2292 */
   1496 				if (OPTBIT(IN6P_RFC2292)) {
   1497 					error = EINVAL;
   1498 					break;
   1499 				}
   1500 #endif
   1501 				OPTSET(IN6P_RTHDR);
   1502 				break;
   1503 
   1504 			case IPV6_FAITH:
   1505 				OPTSET(IN6P_FAITH);
   1506 				break;
   1507 
   1508 			case IPV6_RECVPATHMTU:
   1509 				/*
   1510 				 * We ignore this option for TCP
   1511 				 * sockets.
   1512 				 * (RFC3542 leaves this case
   1513 				 * unspecified.)
   1514 				 */
   1515 				if (uproto != IPPROTO_TCP)
   1516 					OPTSET(IN6P_MTU);
   1517 				break;
   1518 
   1519 			case IPV6_V6ONLY:
   1520 				/*
   1521 				 * make setsockopt(IPV6_V6ONLY)
   1522 				 * available only prior to bind(2).
   1523 				 * see ipng mailing list, Jun 22 2001.
   1524 				 */
   1525 				if (in6p->in6p_lport ||
   1526 				    !IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_laddr)) {
   1527 					error = EINVAL;
   1528 					break;
   1529 				}
   1530 #ifdef INET6_BINDV6ONLY
   1531 				if (!optval)
   1532 					error = EINVAL;
   1533 #else
   1534 				OPTSET(IN6P_IPV6_V6ONLY);
   1535 #endif
   1536 				break;
   1537 			case IPV6_RECVTCLASS:
   1538 #ifdef RFC2292
   1539 				/* cannot mix with RFC2292 XXX */
   1540 				if (OPTBIT(IN6P_RFC2292)) {
   1541 					error = EINVAL;
   1542 					break;
   1543 				}
   1544 #endif
   1545 				OPTSET(IN6P_TCLASS);
   1546 				break;
   1547 
   1548 			}
   1549 			break;
   1550 
   1551 		case IPV6_OTCLASS:
   1552 		{
   1553 			struct ip6_pktopts **optp;
   1554 			u_int8_t tclass;
   1555 
   1556 			error = sockopt_get(sopt, &tclass, sizeof(tclass));
   1557 			if (error)
   1558 				break;
   1559 			optp = &in6p->in6p_outputopts;
   1560 			error = ip6_pcbopt(optname,
   1561 					   (u_char *)&tclass,
   1562 					   sizeof(tclass),
   1563 					   optp,
   1564 					   kauth_cred_get(), uproto);
   1565 			break;
   1566 		}
   1567 
   1568 		case IPV6_TCLASS:
   1569 		case IPV6_DONTFRAG:
   1570 		case IPV6_USE_MIN_MTU:
   1571 		case IPV6_PREFER_TEMPADDR:
   1572 			error = sockopt_getint(sopt, &optval);
   1573 			if (error)
   1574 				break;
   1575 			{
   1576 				struct ip6_pktopts **optp;
   1577 				optp = &in6p->in6p_outputopts;
   1578 				error = ip6_pcbopt(optname,
   1579 						   (u_char *)&optval,
   1580 						   sizeof(optval),
   1581 						   optp,
   1582 						   kauth_cred_get(), uproto);
   1583 				break;
   1584 			}
   1585 
   1586 #ifdef RFC2292
   1587 		case IPV6_2292PKTINFO:
   1588 		case IPV6_2292HOPLIMIT:
   1589 		case IPV6_2292HOPOPTS:
   1590 		case IPV6_2292DSTOPTS:
   1591 		case IPV6_2292RTHDR:
   1592 			/* RFC 2292 */
   1593 			error = sockopt_getint(sopt, &optval);
   1594 			if (error)
   1595 				break;
   1596 
   1597 			switch (optname) {
   1598 			case IPV6_2292PKTINFO:
   1599 				OPTSET2292(IN6P_PKTINFO);
   1600 				break;
   1601 			case IPV6_2292HOPLIMIT:
   1602 				OPTSET2292(IN6P_HOPLIMIT);
   1603 				break;
   1604 			case IPV6_2292HOPOPTS:
   1605 				/*
   1606 				 * Check super-user privilege.
   1607 				 * See comments for IPV6_RECVHOPOPTS.
   1608 				 */
   1609 				error =
   1610 				    kauth_authorize_network(kauth_cred_get(),
   1611 				    KAUTH_NETWORK_IPV6,
   1612 				    KAUTH_REQ_NETWORK_IPV6_HOPBYHOP, NULL,
   1613 				    NULL, NULL);
   1614 				if (error)
   1615 					return (error);
   1616 				OPTSET2292(IN6P_HOPOPTS);
   1617 				break;
   1618 			case IPV6_2292DSTOPTS:
   1619 				error =
   1620 				    kauth_authorize_network(kauth_cred_get(),
   1621 				    KAUTH_NETWORK_IPV6,
   1622 				    KAUTH_REQ_NETWORK_IPV6_HOPBYHOP, NULL,
   1623 				    NULL, NULL);
   1624 				if (error)
   1625 					return (error);
   1626 				OPTSET2292(IN6P_DSTOPTS|IN6P_RTHDRDSTOPTS); /* XXX */
   1627 				break;
   1628 			case IPV6_2292RTHDR:
   1629 				OPTSET2292(IN6P_RTHDR);
   1630 				break;
   1631 			}
   1632 			break;
   1633 #endif
   1634 		case IPV6_PKTINFO:
   1635 		case IPV6_HOPOPTS:
   1636 		case IPV6_RTHDR:
   1637 		case IPV6_DSTOPTS:
   1638 		case IPV6_RTHDRDSTOPTS:
   1639 		case IPV6_NEXTHOP: {
   1640 			/* new advanced API (RFC3542) */
   1641 			void *optbuf;
   1642 			int optbuflen;
   1643 			struct ip6_pktopts **optp;
   1644 
   1645 #ifdef RFC2292
   1646 			/* cannot mix with RFC2292 */
   1647 			if (OPTBIT(IN6P_RFC2292)) {
   1648 				error = EINVAL;
   1649 				break;
   1650 			}
   1651 #endif
   1652 
   1653 			optbuflen = sopt->sopt_size;
   1654 			optbuf = malloc(optbuflen, M_IP6OPT, M_NOWAIT);
   1655 			if (optbuf == NULL) {
   1656 				error = ENOBUFS;
   1657 				break;
   1658 			}
   1659 
   1660 			error = sockopt_get(sopt, optbuf, optbuflen);
   1661 			if (error) {
   1662 				free(optbuf, M_IP6OPT);
   1663 				break;
   1664 			}
   1665 			optp = &in6p->in6p_outputopts;
   1666 			error = ip6_pcbopt(optname, optbuf, optbuflen,
   1667 			    optp, kauth_cred_get(), uproto);
   1668 
   1669 			free(optbuf, M_IP6OPT);
   1670 			break;
   1671 			}
   1672 #undef OPTSET
   1673 
   1674 		case IPV6_MULTICAST_IF:
   1675 		case IPV6_MULTICAST_HOPS:
   1676 		case IPV6_MULTICAST_LOOP:
   1677 		case IPV6_JOIN_GROUP:
   1678 		case IPV6_LEAVE_GROUP:
   1679 			error = ip6_setmoptions(sopt, in6p);
   1680 			break;
   1681 
   1682 		case IPV6_PORTRANGE:
   1683 			error = sockopt_getint(sopt, &optval);
   1684 			if (error)
   1685 				break;
   1686 
   1687 			switch (optval) {
   1688 			case IPV6_PORTRANGE_DEFAULT:
   1689 				in6p->in6p_flags &= ~(IN6P_LOWPORT);
   1690 				in6p->in6p_flags &= ~(IN6P_HIGHPORT);
   1691 				break;
   1692 
   1693 			case IPV6_PORTRANGE_HIGH:
   1694 				in6p->in6p_flags &= ~(IN6P_LOWPORT);
   1695 				in6p->in6p_flags |= IN6P_HIGHPORT;
   1696 				break;
   1697 
   1698 			case IPV6_PORTRANGE_LOW:
   1699 				in6p->in6p_flags &= ~(IN6P_HIGHPORT);
   1700 				in6p->in6p_flags |= IN6P_LOWPORT;
   1701 				break;
   1702 
   1703 			default:
   1704 				error = EINVAL;
   1705 				break;
   1706 			}
   1707 			break;
   1708 
   1709 		case IPV6_PORTALGO:
   1710 			error = sockopt_getint(sopt, &optval);
   1711 			if (error)
   1712 				break;
   1713 
   1714 			error = portalgo_algo_index_select(
   1715 			    (struct inpcb_hdr *)in6p, optval);
   1716 			break;
   1717 
   1718 #if defined(IPSEC)
   1719 		case IPV6_IPSEC_POLICY:
   1720 			if (ipsec_enabled) {
   1721 				error = ipsec6_set_policy(in6p, optname,
   1722 				    sopt->sopt_data, sopt->sopt_size,
   1723 				    kauth_cred_get());
   1724 				break;
   1725 			}
   1726 			/*FALLTHROUGH*/
   1727 #endif /* IPSEC */
   1728 
   1729 		default:
   1730 			error = ENOPROTOOPT;
   1731 			break;
   1732 		}
   1733 		break;
   1734 
   1735 	case PRCO_GETOPT:
   1736 		switch (optname) {
   1737 #ifdef RFC2292
   1738 		case IPV6_2292PKTOPTIONS:
   1739 			/*
   1740 			 * RFC3542 (effectively) deprecated the
   1741 			 * semantics of the 2292-style pktoptions.
   1742 			 * Since it was not reliable in nature (i.e.,
   1743 			 * applications had to expect the lack of some
   1744 			 * information after all), it would make sense
   1745 			 * to simplify this part by always returning
   1746 			 * empty data.
   1747 			 */
   1748 			break;
   1749 #endif
   1750 
   1751 		case IPV6_RECVHOPOPTS:
   1752 		case IPV6_RECVDSTOPTS:
   1753 		case IPV6_RECVRTHDRDSTOPTS:
   1754 		case IPV6_UNICAST_HOPS:
   1755 		case IPV6_RECVPKTINFO:
   1756 		case IPV6_RECVHOPLIMIT:
   1757 		case IPV6_RECVRTHDR:
   1758 		case IPV6_RECVPATHMTU:
   1759 
   1760 		case IPV6_FAITH:
   1761 		case IPV6_V6ONLY:
   1762 		case IPV6_PORTRANGE:
   1763 		case IPV6_RECVTCLASS:
   1764 			switch (optname) {
   1765 
   1766 			case IPV6_RECVHOPOPTS:
   1767 				optval = OPTBIT(IN6P_HOPOPTS);
   1768 				break;
   1769 
   1770 			case IPV6_RECVDSTOPTS:
   1771 				optval = OPTBIT(IN6P_DSTOPTS);
   1772 				break;
   1773 
   1774 			case IPV6_RECVRTHDRDSTOPTS:
   1775 				optval = OPTBIT(IN6P_RTHDRDSTOPTS);
   1776 				break;
   1777 
   1778 			case IPV6_UNICAST_HOPS:
   1779 				optval = in6p->in6p_hops;
   1780 				break;
   1781 
   1782 			case IPV6_RECVPKTINFO:
   1783 				optval = OPTBIT(IN6P_PKTINFO);
   1784 				break;
   1785 
   1786 			case IPV6_RECVHOPLIMIT:
   1787 				optval = OPTBIT(IN6P_HOPLIMIT);
   1788 				break;
   1789 
   1790 			case IPV6_RECVRTHDR:
   1791 				optval = OPTBIT(IN6P_RTHDR);
   1792 				break;
   1793 
   1794 			case IPV6_RECVPATHMTU:
   1795 				optval = OPTBIT(IN6P_MTU);
   1796 				break;
   1797 
   1798 			case IPV6_FAITH:
   1799 				optval = OPTBIT(IN6P_FAITH);
   1800 				break;
   1801 
   1802 			case IPV6_V6ONLY:
   1803 				optval = OPTBIT(IN6P_IPV6_V6ONLY);
   1804 				break;
   1805 
   1806 			case IPV6_PORTRANGE:
   1807 			    {
   1808 				int flags;
   1809 				flags = in6p->in6p_flags;
   1810 				if (flags & IN6P_HIGHPORT)
   1811 					optval = IPV6_PORTRANGE_HIGH;
   1812 				else if (flags & IN6P_LOWPORT)
   1813 					optval = IPV6_PORTRANGE_LOW;
   1814 				else
   1815 					optval = 0;
   1816 				break;
   1817 			    }
   1818 			case IPV6_RECVTCLASS:
   1819 				optval = OPTBIT(IN6P_TCLASS);
   1820 				break;
   1821 
   1822 			}
   1823 			if (error)
   1824 				break;
   1825 			error = sockopt_setint(sopt, optval);
   1826 			break;
   1827 
   1828 		case IPV6_PATHMTU:
   1829 		    {
   1830 			u_long pmtu = 0;
   1831 			struct ip6_mtuinfo mtuinfo;
   1832 			struct route *ro = &in6p->in6p_route;
   1833 
   1834 			if (!(so->so_state & SS_ISCONNECTED))
   1835 				return (ENOTCONN);
   1836 			/*
   1837 			 * XXX: we dot not consider the case of source
   1838 			 * routing, or optional information to specify
   1839 			 * the outgoing interface.
   1840 			 */
   1841 			error = ip6_getpmtu(ro, NULL, NULL,
   1842 			    &in6p->in6p_faddr, &pmtu, NULL);
   1843 			if (error)
   1844 				break;
   1845 			if (pmtu > IPV6_MAXPACKET)
   1846 				pmtu = IPV6_MAXPACKET;
   1847 
   1848 			memset(&mtuinfo, 0, sizeof(mtuinfo));
   1849 			mtuinfo.ip6m_mtu = (u_int32_t)pmtu;
   1850 			optdata = (void *)&mtuinfo;
   1851 			optdatalen = sizeof(mtuinfo);
   1852 			if (optdatalen > MCLBYTES)
   1853 				return (EMSGSIZE); /* XXX */
   1854 			error = sockopt_set(sopt, optdata, optdatalen);
   1855 			break;
   1856 		    }
   1857 
   1858 #ifdef RFC2292
   1859 		case IPV6_2292PKTINFO:
   1860 		case IPV6_2292HOPLIMIT:
   1861 		case IPV6_2292HOPOPTS:
   1862 		case IPV6_2292RTHDR:
   1863 		case IPV6_2292DSTOPTS:
   1864 			switch (optname) {
   1865 			case IPV6_2292PKTINFO:
   1866 				optval = OPTBIT(IN6P_PKTINFO);
   1867 				break;
   1868 			case IPV6_2292HOPLIMIT:
   1869 				optval = OPTBIT(IN6P_HOPLIMIT);
   1870 				break;
   1871 			case IPV6_2292HOPOPTS:
   1872 				optval = OPTBIT(IN6P_HOPOPTS);
   1873 				break;
   1874 			case IPV6_2292RTHDR:
   1875 				optval = OPTBIT(IN6P_RTHDR);
   1876 				break;
   1877 			case IPV6_2292DSTOPTS:
   1878 				optval = OPTBIT(IN6P_DSTOPTS|IN6P_RTHDRDSTOPTS);
   1879 				break;
   1880 			}
   1881 			error = sockopt_setint(sopt, optval);
   1882 			break;
   1883 #endif
   1884 		case IPV6_PKTINFO:
   1885 		case IPV6_HOPOPTS:
   1886 		case IPV6_RTHDR:
   1887 		case IPV6_DSTOPTS:
   1888 		case IPV6_RTHDRDSTOPTS:
   1889 		case IPV6_NEXTHOP:
   1890 		case IPV6_OTCLASS:
   1891 		case IPV6_TCLASS:
   1892 		case IPV6_DONTFRAG:
   1893 		case IPV6_USE_MIN_MTU:
   1894 		case IPV6_PREFER_TEMPADDR:
   1895 			error = ip6_getpcbopt(in6p->in6p_outputopts,
   1896 			    optname, sopt);
   1897 			break;
   1898 
   1899 		case IPV6_MULTICAST_IF:
   1900 		case IPV6_MULTICAST_HOPS:
   1901 		case IPV6_MULTICAST_LOOP:
   1902 		case IPV6_JOIN_GROUP:
   1903 		case IPV6_LEAVE_GROUP:
   1904 			error = ip6_getmoptions(sopt, in6p);
   1905 			break;
   1906 
   1907 		case IPV6_PORTALGO:
   1908 			optval = ((struct inpcb_hdr *)in6p)->inph_portalgo;
   1909 			error = sockopt_setint(sopt, optval);
   1910 			break;
   1911 
   1912 #if defined(IPSEC)
   1913 		case IPV6_IPSEC_POLICY:
   1914 			if (ipsec_used) {
   1915 				struct mbuf *m = NULL;
   1916 
   1917 				/*
   1918 				 * XXX: this will return EINVAL as sopt is
   1919 				 * empty
   1920 				 */
   1921 				error = ipsec6_get_policy(in6p, sopt->sopt_data,
   1922 				    sopt->sopt_size, &m);
   1923 				if (!error)
   1924 					error = sockopt_setmbuf(sopt, m);
   1925 				break;
   1926 			}
   1927 			/*FALLTHROUGH*/
   1928 #endif /* IPSEC */
   1929 
   1930 		default:
   1931 			error = ENOPROTOOPT;
   1932 			break;
   1933 		}
   1934 		break;
   1935 	}
   1936 	return (error);
   1937 }
   1938 
   1939 int
   1940 ip6_raw_ctloutput(int op, struct socket *so, struct sockopt *sopt)
   1941 {
   1942 	int error = 0, optval;
   1943 	const int icmp6off = offsetof(struct icmp6_hdr, icmp6_cksum);
   1944 	struct in6pcb *in6p = sotoin6pcb(so);
   1945 	int level, optname;
   1946 
   1947 	KASSERT(sopt != NULL);
   1948 
   1949 	level = sopt->sopt_level;
   1950 	optname = sopt->sopt_name;
   1951 
   1952 	if (level != IPPROTO_IPV6) {
   1953 		return ENOPROTOOPT;
   1954 	}
   1955 
   1956 	switch (optname) {
   1957 	case IPV6_CHECKSUM:
   1958 		/*
   1959 		 * For ICMPv6 sockets, no modification allowed for checksum
   1960 		 * offset, permit "no change" values to help existing apps.
   1961 		 *
   1962 		 * XXX RFC3542 says: "An attempt to set IPV6_CHECKSUM
   1963 		 * for an ICMPv6 socket will fail."  The current
   1964 		 * behavior does not meet RFC3542.
   1965 		 */
   1966 		switch (op) {
   1967 		case PRCO_SETOPT:
   1968 			error = sockopt_getint(sopt, &optval);
   1969 			if (error)
   1970 				break;
   1971 			if ((optval % 2) != 0) {
   1972 				/* the API assumes even offset values */
   1973 				error = EINVAL;
   1974 			} else if (so->so_proto->pr_protocol ==
   1975 			    IPPROTO_ICMPV6) {
   1976 				if (optval != icmp6off)
   1977 					error = EINVAL;
   1978 			} else
   1979 				in6p->in6p_cksum = optval;
   1980 			break;
   1981 
   1982 		case PRCO_GETOPT:
   1983 			if (so->so_proto->pr_protocol == IPPROTO_ICMPV6)
   1984 				optval = icmp6off;
   1985 			else
   1986 				optval = in6p->in6p_cksum;
   1987 
   1988 			error = sockopt_setint(sopt, optval);
   1989 			break;
   1990 
   1991 		default:
   1992 			error = EINVAL;
   1993 			break;
   1994 		}
   1995 		break;
   1996 
   1997 	default:
   1998 		error = ENOPROTOOPT;
   1999 		break;
   2000 	}
   2001 
   2002 	return (error);
   2003 }
   2004 
   2005 #ifdef RFC2292
   2006 /*
   2007  * Set up IP6 options in pcb for insertion in output packets or
   2008  * specifying behavior of outgoing packets.
   2009  */
   2010 static int
   2011 ip6_pcbopts(struct ip6_pktopts **pktopt, struct socket *so,
   2012     struct sockopt *sopt)
   2013 {
   2014 	struct ip6_pktopts *opt = *pktopt;
   2015 	struct mbuf *m;
   2016 	int error = 0;
   2017 
   2018 	/* turn off any old options. */
   2019 	if (opt) {
   2020 #ifdef DIAGNOSTIC
   2021 	    if (opt->ip6po_pktinfo || opt->ip6po_nexthop ||
   2022 		opt->ip6po_hbh || opt->ip6po_dest1 || opt->ip6po_dest2 ||
   2023 		opt->ip6po_rhinfo.ip6po_rhi_rthdr)
   2024 		    printf("ip6_pcbopts: all specified options are cleared.\n");
   2025 #endif
   2026 		ip6_clearpktopts(opt, -1);
   2027 	} else {
   2028 		opt = malloc(sizeof(*opt), M_IP6OPT, M_NOWAIT);
   2029 		if (opt == NULL)
   2030 			return (ENOBUFS);
   2031 	}
   2032 	*pktopt = NULL;
   2033 
   2034 	if (sopt == NULL || sopt->sopt_size == 0) {
   2035 		/*
   2036 		 * Only turning off any previous options, regardless of
   2037 		 * whether the opt is just created or given.
   2038 		 */
   2039 		free(opt, M_IP6OPT);
   2040 		return (0);
   2041 	}
   2042 
   2043 	/*  set options specified by user. */
   2044 	m = sockopt_getmbuf(sopt);
   2045 	if (m == NULL) {
   2046 		free(opt, M_IP6OPT);
   2047 		return (ENOBUFS);
   2048 	}
   2049 
   2050 	error = ip6_setpktopts(m, opt, NULL, kauth_cred_get(),
   2051 	    so->so_proto->pr_protocol);
   2052 	m_freem(m);
   2053 	if (error != 0) {
   2054 		ip6_clearpktopts(opt, -1); /* XXX: discard all options */
   2055 		free(opt, M_IP6OPT);
   2056 		return (error);
   2057 	}
   2058 	*pktopt = opt;
   2059 	return (0);
   2060 }
   2061 #endif
   2062 
   2063 /*
   2064  * initialize ip6_pktopts.  beware that there are non-zero default values in
   2065  * the struct.
   2066  */
   2067 void
   2068 ip6_initpktopts(struct ip6_pktopts *opt)
   2069 {
   2070 
   2071 	memset(opt, 0, sizeof(*opt));
   2072 	opt->ip6po_hlim = -1;	/* -1 means default hop limit */
   2073 	opt->ip6po_tclass = -1;	/* -1 means default traffic class */
   2074 	opt->ip6po_minmtu = IP6PO_MINMTU_MCASTONLY;
   2075 	opt->ip6po_prefer_tempaddr = IP6PO_TEMPADDR_SYSTEM;
   2076 }
   2077 
   2078 #define sin6tosa(sin6)	((struct sockaddr *)(sin6)) /* XXX */
   2079 static int
   2080 ip6_pcbopt(int optname, u_char *buf, int len, struct ip6_pktopts **pktopt,
   2081     kauth_cred_t cred, int uproto)
   2082 {
   2083 	struct ip6_pktopts *opt;
   2084 
   2085 	if (*pktopt == NULL) {
   2086 		*pktopt = malloc(sizeof(struct ip6_pktopts), M_IP6OPT,
   2087 		    M_NOWAIT);
   2088 		if (*pktopt == NULL)
   2089 			return (ENOBUFS);
   2090 
   2091 		ip6_initpktopts(*pktopt);
   2092 	}
   2093 	opt = *pktopt;
   2094 
   2095 	return (ip6_setpktopt(optname, buf, len, opt, cred, 1, 0, uproto));
   2096 }
   2097 
   2098 static int
   2099 ip6_getpcbopt(struct ip6_pktopts *pktopt, int optname, struct sockopt *sopt)
   2100 {
   2101 	void *optdata = NULL;
   2102 	int optdatalen = 0;
   2103 	struct ip6_ext *ip6e;
   2104 	int error = 0;
   2105 	struct in6_pktinfo null_pktinfo;
   2106 	int deftclass = 0, on;
   2107 	int defminmtu = IP6PO_MINMTU_MCASTONLY;
   2108 	int defpreftemp = IP6PO_TEMPADDR_SYSTEM;
   2109 
   2110 	switch (optname) {
   2111 	case IPV6_PKTINFO:
   2112 		if (pktopt && pktopt->ip6po_pktinfo)
   2113 			optdata = (void *)pktopt->ip6po_pktinfo;
   2114 		else {
   2115 			/* XXX: we don't have to do this every time... */
   2116 			memset(&null_pktinfo, 0, sizeof(null_pktinfo));
   2117 			optdata = (void *)&null_pktinfo;
   2118 		}
   2119 		optdatalen = sizeof(struct in6_pktinfo);
   2120 		break;
   2121 	case IPV6_OTCLASS:
   2122 		/* XXX */
   2123 		return (EINVAL);
   2124 	case IPV6_TCLASS:
   2125 		if (pktopt && pktopt->ip6po_tclass >= 0)
   2126 			optdata = (void *)&pktopt->ip6po_tclass;
   2127 		else
   2128 			optdata = (void *)&deftclass;
   2129 		optdatalen = sizeof(int);
   2130 		break;
   2131 	case IPV6_HOPOPTS:
   2132 		if (pktopt && pktopt->ip6po_hbh) {
   2133 			optdata = (void *)pktopt->ip6po_hbh;
   2134 			ip6e = (struct ip6_ext *)pktopt->ip6po_hbh;
   2135 			optdatalen = (ip6e->ip6e_len + 1) << 3;
   2136 		}
   2137 		break;
   2138 	case IPV6_RTHDR:
   2139 		if (pktopt && pktopt->ip6po_rthdr) {
   2140 			optdata = (void *)pktopt->ip6po_rthdr;
   2141 			ip6e = (struct ip6_ext *)pktopt->ip6po_rthdr;
   2142 			optdatalen = (ip6e->ip6e_len + 1) << 3;
   2143 		}
   2144 		break;
   2145 	case IPV6_RTHDRDSTOPTS:
   2146 		if (pktopt && pktopt->ip6po_dest1) {
   2147 			optdata = (void *)pktopt->ip6po_dest1;
   2148 			ip6e = (struct ip6_ext *)pktopt->ip6po_dest1;
   2149 			optdatalen = (ip6e->ip6e_len + 1) << 3;
   2150 		}
   2151 		break;
   2152 	case IPV6_DSTOPTS:
   2153 		if (pktopt && pktopt->ip6po_dest2) {
   2154 			optdata = (void *)pktopt->ip6po_dest2;
   2155 			ip6e = (struct ip6_ext *)pktopt->ip6po_dest2;
   2156 			optdatalen = (ip6e->ip6e_len + 1) << 3;
   2157 		}
   2158 		break;
   2159 	case IPV6_NEXTHOP:
   2160 		if (pktopt && pktopt->ip6po_nexthop) {
   2161 			optdata = (void *)pktopt->ip6po_nexthop;
   2162 			optdatalen = pktopt->ip6po_nexthop->sa_len;
   2163 		}
   2164 		break;
   2165 	case IPV6_USE_MIN_MTU:
   2166 		if (pktopt)
   2167 			optdata = (void *)&pktopt->ip6po_minmtu;
   2168 		else
   2169 			optdata = (void *)&defminmtu;
   2170 		optdatalen = sizeof(int);
   2171 		break;
   2172 	case IPV6_DONTFRAG:
   2173 		if (pktopt && ((pktopt->ip6po_flags) & IP6PO_DONTFRAG))
   2174 			on = 1;
   2175 		else
   2176 			on = 0;
   2177 		optdata = (void *)&on;
   2178 		optdatalen = sizeof(on);
   2179 		break;
   2180 	case IPV6_PREFER_TEMPADDR:
   2181 		if (pktopt)
   2182 			optdata = (void *)&pktopt->ip6po_prefer_tempaddr;
   2183 		else
   2184 			optdata = (void *)&defpreftemp;
   2185 		optdatalen = sizeof(int);
   2186 		break;
   2187 	default:		/* should not happen */
   2188 #ifdef DIAGNOSTIC
   2189 		panic("ip6_getpcbopt: unexpected option\n");
   2190 #endif
   2191 		return (ENOPROTOOPT);
   2192 	}
   2193 
   2194 	error = sockopt_set(sopt, optdata, optdatalen);
   2195 
   2196 	return (error);
   2197 }
   2198 
   2199 void
   2200 ip6_clearpktopts(struct ip6_pktopts *pktopt, int optname)
   2201 {
   2202 	if (optname == -1 || optname == IPV6_PKTINFO) {
   2203 		if (pktopt->ip6po_pktinfo)
   2204 			free(pktopt->ip6po_pktinfo, M_IP6OPT);
   2205 		pktopt->ip6po_pktinfo = NULL;
   2206 	}
   2207 	if (optname == -1 || optname == IPV6_HOPLIMIT)
   2208 		pktopt->ip6po_hlim = -1;
   2209 	if (optname == -1 || optname == IPV6_TCLASS)
   2210 		pktopt->ip6po_tclass = -1;
   2211 	if (optname == -1 || optname == IPV6_NEXTHOP) {
   2212 		rtcache_free(&pktopt->ip6po_nextroute);
   2213 		if (pktopt->ip6po_nexthop)
   2214 			free(pktopt->ip6po_nexthop, M_IP6OPT);
   2215 		pktopt->ip6po_nexthop = NULL;
   2216 	}
   2217 	if (optname == -1 || optname == IPV6_HOPOPTS) {
   2218 		if (pktopt->ip6po_hbh)
   2219 			free(pktopt->ip6po_hbh, M_IP6OPT);
   2220 		pktopt->ip6po_hbh = NULL;
   2221 	}
   2222 	if (optname == -1 || optname == IPV6_RTHDRDSTOPTS) {
   2223 		if (pktopt->ip6po_dest1)
   2224 			free(pktopt->ip6po_dest1, M_IP6OPT);
   2225 		pktopt->ip6po_dest1 = NULL;
   2226 	}
   2227 	if (optname == -1 || optname == IPV6_RTHDR) {
   2228 		if (pktopt->ip6po_rhinfo.ip6po_rhi_rthdr)
   2229 			free(pktopt->ip6po_rhinfo.ip6po_rhi_rthdr, M_IP6OPT);
   2230 		pktopt->ip6po_rhinfo.ip6po_rhi_rthdr = NULL;
   2231 		rtcache_free(&pktopt->ip6po_route);
   2232 	}
   2233 	if (optname == -1 || optname == IPV6_DSTOPTS) {
   2234 		if (pktopt->ip6po_dest2)
   2235 			free(pktopt->ip6po_dest2, M_IP6OPT);
   2236 		pktopt->ip6po_dest2 = NULL;
   2237 	}
   2238 }
   2239 
   2240 #define PKTOPT_EXTHDRCPY(type) 					\
   2241 do {								\
   2242 	if (src->type) {					\
   2243 		int hlen = (((struct ip6_ext *)src->type)->ip6e_len + 1) << 3;\
   2244 		dst->type = malloc(hlen, M_IP6OPT, canwait);	\
   2245 		if (dst->type == NULL)				\
   2246 			goto bad;				\
   2247 		memcpy(dst->type, src->type, hlen);		\
   2248 	}							\
   2249 } while (/*CONSTCOND*/ 0)
   2250 
   2251 static int
   2252 copypktopts(struct ip6_pktopts *dst, struct ip6_pktopts *src, int canwait)
   2253 {
   2254 	dst->ip6po_hlim = src->ip6po_hlim;
   2255 	dst->ip6po_tclass = src->ip6po_tclass;
   2256 	dst->ip6po_flags = src->ip6po_flags;
   2257 	dst->ip6po_minmtu = src->ip6po_minmtu;
   2258 	dst->ip6po_prefer_tempaddr = src->ip6po_prefer_tempaddr;
   2259 	if (src->ip6po_pktinfo) {
   2260 		dst->ip6po_pktinfo = malloc(sizeof(*dst->ip6po_pktinfo),
   2261 		    M_IP6OPT, canwait);
   2262 		if (dst->ip6po_pktinfo == NULL)
   2263 			goto bad;
   2264 		*dst->ip6po_pktinfo = *src->ip6po_pktinfo;
   2265 	}
   2266 	if (src->ip6po_nexthop) {
   2267 		dst->ip6po_nexthop = malloc(src->ip6po_nexthop->sa_len,
   2268 		    M_IP6OPT, canwait);
   2269 		if (dst->ip6po_nexthop == NULL)
   2270 			goto bad;
   2271 		memcpy(dst->ip6po_nexthop, src->ip6po_nexthop,
   2272 		    src->ip6po_nexthop->sa_len);
   2273 	}
   2274 	PKTOPT_EXTHDRCPY(ip6po_hbh);
   2275 	PKTOPT_EXTHDRCPY(ip6po_dest1);
   2276 	PKTOPT_EXTHDRCPY(ip6po_dest2);
   2277 	PKTOPT_EXTHDRCPY(ip6po_rthdr); /* not copy the cached route */
   2278 	return (0);
   2279 
   2280   bad:
   2281 	if (dst->ip6po_pktinfo) free(dst->ip6po_pktinfo, M_IP6OPT);
   2282 	if (dst->ip6po_nexthop) free(dst->ip6po_nexthop, M_IP6OPT);
   2283 	if (dst->ip6po_hbh) free(dst->ip6po_hbh, M_IP6OPT);
   2284 	if (dst->ip6po_dest1) free(dst->ip6po_dest1, M_IP6OPT);
   2285 	if (dst->ip6po_dest2) free(dst->ip6po_dest2, M_IP6OPT);
   2286 	if (dst->ip6po_rthdr) free(dst->ip6po_rthdr, M_IP6OPT);
   2287 
   2288 	return (ENOBUFS);
   2289 }
   2290 #undef PKTOPT_EXTHDRCPY
   2291 
   2292 struct ip6_pktopts *
   2293 ip6_copypktopts(struct ip6_pktopts *src, int canwait)
   2294 {
   2295 	int error;
   2296 	struct ip6_pktopts *dst;
   2297 
   2298 	dst = malloc(sizeof(*dst), M_IP6OPT, canwait);
   2299 	if (dst == NULL)
   2300 		return (NULL);
   2301 	ip6_initpktopts(dst);
   2302 
   2303 	if ((error = copypktopts(dst, src, canwait)) != 0) {
   2304 		free(dst, M_IP6OPT);
   2305 		return (NULL);
   2306 	}
   2307 
   2308 	return (dst);
   2309 }
   2310 
   2311 void
   2312 ip6_freepcbopts(struct ip6_pktopts *pktopt)
   2313 {
   2314 	if (pktopt == NULL)
   2315 		return;
   2316 
   2317 	ip6_clearpktopts(pktopt, -1);
   2318 
   2319 	free(pktopt, M_IP6OPT);
   2320 }
   2321 
   2322 int
   2323 ip6_get_membership(const struct sockopt *sopt, struct ifnet **ifp, void *v,
   2324     size_t l)
   2325 {
   2326 	struct ipv6_mreq mreq;
   2327 	int error;
   2328 	struct in6_addr *ia = &mreq.ipv6mr_multiaddr;
   2329 	struct in_addr *ia4 = (void *)&ia->s6_addr32[3];
   2330 	error = sockopt_get(sopt, &mreq, sizeof(mreq));
   2331 	if (error != 0)
   2332 		return error;
   2333 
   2334 	if (IN6_IS_ADDR_UNSPECIFIED(ia)) {
   2335 		/*
   2336 		 * We use the unspecified address to specify to accept
   2337 		 * all multicast addresses. Only super user is allowed
   2338 		 * to do this.
   2339 		 */
   2340 		if (kauth_authorize_network(curlwp->l_cred, KAUTH_NETWORK_IPV6,
   2341 		    KAUTH_REQ_NETWORK_IPV6_JOIN_MULTICAST, NULL, NULL, NULL))
   2342 			return EACCES;
   2343 	} else if (IN6_IS_ADDR_V4MAPPED(ia)) {
   2344 		// Don't bother if we are not going to use ifp.
   2345 		if (l == sizeof(*ia)) {
   2346 			memcpy(v, ia, l);
   2347 			return 0;
   2348 		}
   2349 	} else if (!IN6_IS_ADDR_MULTICAST(ia)) {
   2350 		return EINVAL;
   2351 	}
   2352 
   2353 	/*
   2354 	 * If no interface was explicitly specified, choose an
   2355 	 * appropriate one according to the given multicast address.
   2356 	 */
   2357 	if (mreq.ipv6mr_interface == 0) {
   2358 		struct rtentry *rt;
   2359 		union {
   2360 			struct sockaddr		dst;
   2361 			struct sockaddr_in	dst4;
   2362 			struct sockaddr_in6	dst6;
   2363 		} u;
   2364 		struct route ro;
   2365 
   2366 		/*
   2367 		 * Look up the routing table for the
   2368 		 * address, and choose the outgoing interface.
   2369 		 *   XXX: is it a good approach?
   2370 		 */
   2371 		memset(&ro, 0, sizeof(ro));
   2372 		if (IN6_IS_ADDR_V4MAPPED(ia))
   2373 			sockaddr_in_init(&u.dst4, ia4, 0);
   2374 		else
   2375 			sockaddr_in6_init(&u.dst6, ia, 0, 0, 0);
   2376 		error = rtcache_setdst(&ro, &u.dst);
   2377 		if (error != 0)
   2378 			return error;
   2379 		*ifp = (rt = rtcache_init(&ro)) != NULL ? rt->rt_ifp : NULL;
   2380 		rtcache_free(&ro);
   2381 	} else {
   2382 		/*
   2383 		 * If the interface is specified, validate it.
   2384 		 */
   2385 		if ((*ifp = if_byindex(mreq.ipv6mr_interface)) == NULL)
   2386 			return ENXIO;	/* XXX EINVAL? */
   2387 	}
   2388 	if (sizeof(*ia) == l)
   2389 		memcpy(v, ia, l);
   2390 	else
   2391 		memcpy(v, ia4, l);
   2392 	return 0;
   2393 }
   2394 
   2395 /*
   2396  * Set the IP6 multicast options in response to user setsockopt().
   2397  */
   2398 static int
   2399 ip6_setmoptions(const struct sockopt *sopt, struct in6pcb *in6p)
   2400 {
   2401 	int error = 0;
   2402 	u_int loop, ifindex;
   2403 	struct ipv6_mreq mreq;
   2404 	struct in6_addr ia;
   2405 	struct ifnet *ifp;
   2406 	struct ip6_moptions *im6o = in6p->in6p_moptions;
   2407 	struct in6_multi_mship *imm;
   2408 
   2409 	if (im6o == NULL) {
   2410 		/*
   2411 		 * No multicast option buffer attached to the pcb;
   2412 		 * allocate one and initialize to default values.
   2413 		 */
   2414 		im6o = malloc(sizeof(*im6o), M_IPMOPTS, M_NOWAIT);
   2415 		if (im6o == NULL)
   2416 			return (ENOBUFS);
   2417 		in6p->in6p_moptions = im6o;
   2418 		im6o->im6o_multicast_if_index = 0;
   2419 		im6o->im6o_multicast_hlim = ip6_defmcasthlim;
   2420 		im6o->im6o_multicast_loop = IPV6_DEFAULT_MULTICAST_LOOP;
   2421 		LIST_INIT(&im6o->im6o_memberships);
   2422 	}
   2423 
   2424 	switch (sopt->sopt_name) {
   2425 
   2426 	case IPV6_MULTICAST_IF:
   2427 		/*
   2428 		 * Select the interface for outgoing multicast packets.
   2429 		 */
   2430 		error = sockopt_get(sopt, &ifindex, sizeof(ifindex));
   2431 		if (error != 0)
   2432 			break;
   2433 
   2434 		if (ifindex != 0) {
   2435 			if ((ifp = if_byindex(ifindex)) == NULL) {
   2436 				error = ENXIO;	/* XXX EINVAL? */
   2437 				break;
   2438 			}
   2439 			if ((ifp->if_flags & IFF_MULTICAST) == 0) {
   2440 				error = EADDRNOTAVAIL;
   2441 				break;
   2442 			}
   2443 		} else
   2444 			ifp = NULL;
   2445 		im6o->im6o_multicast_if_index = if_get_index(ifp);
   2446 		break;
   2447 
   2448 	case IPV6_MULTICAST_HOPS:
   2449 	    {
   2450 		/*
   2451 		 * Set the IP6 hoplimit for outgoing multicast packets.
   2452 		 */
   2453 		int optval;
   2454 
   2455 		error = sockopt_getint(sopt, &optval);
   2456 		if (error != 0)
   2457 			break;
   2458 
   2459 		if (optval < -1 || optval >= 256)
   2460 			error = EINVAL;
   2461 		else if (optval == -1)
   2462 			im6o->im6o_multicast_hlim = ip6_defmcasthlim;
   2463 		else
   2464 			im6o->im6o_multicast_hlim = optval;
   2465 		break;
   2466 	    }
   2467 
   2468 	case IPV6_MULTICAST_LOOP:
   2469 		/*
   2470 		 * Set the loopback flag for outgoing multicast packets.
   2471 		 * Must be zero or one.
   2472 		 */
   2473 		error = sockopt_get(sopt, &loop, sizeof(loop));
   2474 		if (error != 0)
   2475 			break;
   2476 		if (loop > 1) {
   2477 			error = EINVAL;
   2478 			break;
   2479 		}
   2480 		im6o->im6o_multicast_loop = loop;
   2481 		break;
   2482 
   2483 	case IPV6_JOIN_GROUP:
   2484 		/*
   2485 		 * Add a multicast group membership.
   2486 		 * Group must be a valid IP6 multicast address.
   2487 		 */
   2488 		if ((error = ip6_get_membership(sopt, &ifp, &ia, sizeof(ia))))
   2489 			return error;
   2490 
   2491 		if (IN6_IS_ADDR_V4MAPPED(&ia)) {
   2492 			error = ip_setmoptions(&in6p->in6p_v4moptions, sopt);
   2493 			break;
   2494 		}
   2495 		/*
   2496 		 * See if we found an interface, and confirm that it
   2497 		 * supports multicast
   2498 		 */
   2499 		if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) {
   2500 			error = EADDRNOTAVAIL;
   2501 			break;
   2502 		}
   2503 
   2504 		if (in6_setscope(&ia, ifp, NULL)) {
   2505 			error = EADDRNOTAVAIL; /* XXX: should not happen */
   2506 			break;
   2507 		}
   2508 
   2509 		/*
   2510 		 * See if the membership already exists.
   2511 		 */
   2512 		for (imm = im6o->im6o_memberships.lh_first;
   2513 		     imm != NULL; imm = imm->i6mm_chain.le_next)
   2514 			if (imm->i6mm_maddr->in6m_ifp == ifp &&
   2515 			    IN6_ARE_ADDR_EQUAL(&imm->i6mm_maddr->in6m_addr,
   2516 			    &ia))
   2517 				break;
   2518 		if (imm != NULL) {
   2519 			error = EADDRINUSE;
   2520 			break;
   2521 		}
   2522 		/*
   2523 		 * Everything looks good; add a new record to the multicast
   2524 		 * address list for the given interface.
   2525 		 */
   2526 		imm = in6_joingroup(ifp, &ia, &error, 0);
   2527 		if (imm == NULL)
   2528 			break;
   2529 		LIST_INSERT_HEAD(&im6o->im6o_memberships, imm, i6mm_chain);
   2530 		break;
   2531 
   2532 	case IPV6_LEAVE_GROUP:
   2533 		/*
   2534 		 * Drop a multicast group membership.
   2535 		 * Group must be a valid IP6 multicast address.
   2536 		 */
   2537 		error = sockopt_get(sopt, &mreq, sizeof(mreq));
   2538 		if (error != 0)
   2539 			break;
   2540 
   2541 		if (IN6_IS_ADDR_V4MAPPED(&mreq.ipv6mr_multiaddr)) {
   2542 			error = ip_setmoptions(&in6p->in6p_v4moptions, sopt);
   2543 			break;
   2544 		}
   2545 		/*
   2546 		 * If an interface address was specified, get a pointer
   2547 		 * to its ifnet structure.
   2548 		 */
   2549 		if (mreq.ipv6mr_interface != 0) {
   2550 			if ((ifp = if_byindex(mreq.ipv6mr_interface)) == NULL) {
   2551 				error = ENXIO;	/* XXX EINVAL? */
   2552 				break;
   2553 			}
   2554 		} else
   2555 			ifp = NULL;
   2556 
   2557 		/* Fill in the scope zone ID */
   2558 		if (ifp) {
   2559 			if (in6_setscope(&mreq.ipv6mr_multiaddr, ifp, NULL)) {
   2560 				/* XXX: should not happen */
   2561 				error = EADDRNOTAVAIL;
   2562 				break;
   2563 			}
   2564 		} else if (mreq.ipv6mr_interface != 0) {
   2565 			/*
   2566 			 * XXX: This case would happens when the (positive)
   2567 			 * index is in the valid range, but the corresponding
   2568 			 * interface has been detached dynamically.  The above
   2569 			 * check probably avoids such case to happen here, but
   2570 			 * we check it explicitly for safety.
   2571 			 */
   2572 			error = EADDRNOTAVAIL;
   2573 			break;
   2574 		} else {	/* ipv6mr_interface == 0 */
   2575 			struct sockaddr_in6 sa6_mc;
   2576 
   2577 			/*
   2578 			 * The API spec says as follows:
   2579 			 *  If the interface index is specified as 0, the
   2580 			 *  system may choose a multicast group membership to
   2581 			 *  drop by matching the multicast address only.
   2582 			 * On the other hand, we cannot disambiguate the scope
   2583 			 * zone unless an interface is provided.  Thus, we
   2584 			 * check if there's ambiguity with the default scope
   2585 			 * zone as the last resort.
   2586 			 */
   2587 			sockaddr_in6_init(&sa6_mc, &mreq.ipv6mr_multiaddr,
   2588 			    0, 0, 0);
   2589 			error = sa6_embedscope(&sa6_mc, ip6_use_defzone);
   2590 			if (error != 0)
   2591 				break;
   2592 			mreq.ipv6mr_multiaddr = sa6_mc.sin6_addr;
   2593 		}
   2594 
   2595 		/*
   2596 		 * Find the membership in the membership list.
   2597 		 */
   2598 		for (imm = im6o->im6o_memberships.lh_first;
   2599 		     imm != NULL; imm = imm->i6mm_chain.le_next) {
   2600 			if ((ifp == NULL || imm->i6mm_maddr->in6m_ifp == ifp) &&
   2601 			    IN6_ARE_ADDR_EQUAL(&imm->i6mm_maddr->in6m_addr,
   2602 			    &mreq.ipv6mr_multiaddr))
   2603 				break;
   2604 		}
   2605 		if (imm == NULL) {
   2606 			/* Unable to resolve interface */
   2607 			error = EADDRNOTAVAIL;
   2608 			break;
   2609 		}
   2610 		/*
   2611 		 * Give up the multicast address record to which the
   2612 		 * membership points.
   2613 		 */
   2614 		LIST_REMOVE(imm, i6mm_chain);
   2615 		in6_leavegroup(imm);
   2616 		break;
   2617 
   2618 	default:
   2619 		error = EOPNOTSUPP;
   2620 		break;
   2621 	}
   2622 
   2623 	/*
   2624 	 * If all options have default values, no need to keep the mbuf.
   2625 	 */
   2626 	if (im6o->im6o_multicast_if_index == 0 &&
   2627 	    im6o->im6o_multicast_hlim == ip6_defmcasthlim &&
   2628 	    im6o->im6o_multicast_loop == IPV6_DEFAULT_MULTICAST_LOOP &&
   2629 	    im6o->im6o_memberships.lh_first == NULL) {
   2630 		free(in6p->in6p_moptions, M_IPMOPTS);
   2631 		in6p->in6p_moptions = NULL;
   2632 	}
   2633 
   2634 	return (error);
   2635 }
   2636 
   2637 /*
   2638  * Return the IP6 multicast options in response to user getsockopt().
   2639  */
   2640 static int
   2641 ip6_getmoptions(struct sockopt *sopt, struct in6pcb *in6p)
   2642 {
   2643 	u_int optval;
   2644 	int error;
   2645 	struct ip6_moptions *im6o = in6p->in6p_moptions;
   2646 
   2647 	switch (sopt->sopt_name) {
   2648 	case IPV6_MULTICAST_IF:
   2649 		if (im6o == NULL || im6o->im6o_multicast_if_index == 0)
   2650 			optval = 0;
   2651 		else
   2652 			optval = im6o->im6o_multicast_if_index;
   2653 
   2654 		error = sockopt_set(sopt, &optval, sizeof(optval));
   2655 		break;
   2656 
   2657 	case IPV6_MULTICAST_HOPS:
   2658 		if (im6o == NULL)
   2659 			optval = ip6_defmcasthlim;
   2660 		else
   2661 			optval = im6o->im6o_multicast_hlim;
   2662 
   2663 		error = sockopt_set(sopt, &optval, sizeof(optval));
   2664 		break;
   2665 
   2666 	case IPV6_MULTICAST_LOOP:
   2667 		if (im6o == NULL)
   2668 			optval = IPV6_DEFAULT_MULTICAST_LOOP;
   2669 		else
   2670 			optval = im6o->im6o_multicast_loop;
   2671 
   2672 		error = sockopt_set(sopt, &optval, sizeof(optval));
   2673 		break;
   2674 
   2675 	default:
   2676 		error = EOPNOTSUPP;
   2677 	}
   2678 
   2679 	return (error);
   2680 }
   2681 
   2682 /*
   2683  * Discard the IP6 multicast options.
   2684  */
   2685 void
   2686 ip6_freemoptions(struct ip6_moptions *im6o)
   2687 {
   2688 	struct in6_multi_mship *imm;
   2689 
   2690 	if (im6o == NULL)
   2691 		return;
   2692 
   2693 	while ((imm = im6o->im6o_memberships.lh_first) != NULL) {
   2694 		LIST_REMOVE(imm, i6mm_chain);
   2695 		in6_leavegroup(imm);
   2696 	}
   2697 	free(im6o, M_IPMOPTS);
   2698 }
   2699 
   2700 /*
   2701  * Set IPv6 outgoing packet options based on advanced API.
   2702  */
   2703 int
   2704 ip6_setpktopts(struct mbuf *control, struct ip6_pktopts *opt,
   2705 	struct ip6_pktopts *stickyopt, kauth_cred_t cred, int uproto)
   2706 {
   2707 	struct cmsghdr *cm = 0;
   2708 
   2709 	if (control == NULL || opt == NULL)
   2710 		return (EINVAL);
   2711 
   2712 	ip6_initpktopts(opt);
   2713 	if (stickyopt) {
   2714 		int error;
   2715 
   2716 		/*
   2717 		 * If stickyopt is provided, make a local copy of the options
   2718 		 * for this particular packet, then override them by ancillary
   2719 		 * objects.
   2720 		 * XXX: copypktopts() does not copy the cached route to a next
   2721 		 * hop (if any).  This is not very good in terms of efficiency,
   2722 		 * but we can allow this since this option should be rarely
   2723 		 * used.
   2724 		 */
   2725 		if ((error = copypktopts(opt, stickyopt, M_NOWAIT)) != 0)
   2726 			return (error);
   2727 	}
   2728 
   2729 	/*
   2730 	 * XXX: Currently, we assume all the optional information is stored
   2731 	 * in a single mbuf.
   2732 	 */
   2733 	if (control->m_next)
   2734 		return (EINVAL);
   2735 
   2736 	/* XXX if cm->cmsg_len is not aligned, control->m_len can become <0 */
   2737 	for (; control->m_len > 0; control->m_data += CMSG_ALIGN(cm->cmsg_len),
   2738 	    control->m_len -= CMSG_ALIGN(cm->cmsg_len)) {
   2739 		int error;
   2740 
   2741 		if (control->m_len < CMSG_LEN(0))
   2742 			return (EINVAL);
   2743 
   2744 		cm = mtod(control, struct cmsghdr *);
   2745 		if (cm->cmsg_len == 0 || cm->cmsg_len > control->m_len)
   2746 			return (EINVAL);
   2747 		if (cm->cmsg_level != IPPROTO_IPV6)
   2748 			continue;
   2749 
   2750 		error = ip6_setpktopt(cm->cmsg_type, CMSG_DATA(cm),
   2751 		    cm->cmsg_len - CMSG_LEN(0), opt, cred, 0, 1, uproto);
   2752 		if (error)
   2753 			return (error);
   2754 	}
   2755 
   2756 	return (0);
   2757 }
   2758 
   2759 /*
   2760  * Set a particular packet option, as a sticky option or an ancillary data
   2761  * item.  "len" can be 0 only when it's a sticky option.
   2762  * We have 4 cases of combination of "sticky" and "cmsg":
   2763  * "sticky=0, cmsg=0": impossible
   2764  * "sticky=0, cmsg=1": RFC2292 or RFC3542 ancillary data
   2765  * "sticky=1, cmsg=0": RFC3542 socket option
   2766  * "sticky=1, cmsg=1": RFC2292 socket option
   2767  */
   2768 static int
   2769 ip6_setpktopt(int optname, u_char *buf, int len, struct ip6_pktopts *opt,
   2770     kauth_cred_t cred, int sticky, int cmsg, int uproto)
   2771 {
   2772 	int minmtupolicy;
   2773 	int error;
   2774 
   2775 	if (!sticky && !cmsg) {
   2776 #ifdef DIAGNOSTIC
   2777 		printf("ip6_setpktopt: impossible case\n");
   2778 #endif
   2779 		return (EINVAL);
   2780 	}
   2781 
   2782 	/*
   2783 	 * IPV6_2292xxx is for backward compatibility to RFC2292, and should
   2784 	 * not be specified in the context of RFC3542.  Conversely,
   2785 	 * RFC3542 types should not be specified in the context of RFC2292.
   2786 	 */
   2787 	if (!cmsg) {
   2788 		switch (optname) {
   2789 		case IPV6_2292PKTINFO:
   2790 		case IPV6_2292HOPLIMIT:
   2791 		case IPV6_2292NEXTHOP:
   2792 		case IPV6_2292HOPOPTS:
   2793 		case IPV6_2292DSTOPTS:
   2794 		case IPV6_2292RTHDR:
   2795 		case IPV6_2292PKTOPTIONS:
   2796 			return (ENOPROTOOPT);
   2797 		}
   2798 	}
   2799 	if (sticky && cmsg) {
   2800 		switch (optname) {
   2801 		case IPV6_PKTINFO:
   2802 		case IPV6_HOPLIMIT:
   2803 		case IPV6_NEXTHOP:
   2804 		case IPV6_HOPOPTS:
   2805 		case IPV6_DSTOPTS:
   2806 		case IPV6_RTHDRDSTOPTS:
   2807 		case IPV6_RTHDR:
   2808 		case IPV6_USE_MIN_MTU:
   2809 		case IPV6_DONTFRAG:
   2810 		case IPV6_OTCLASS:
   2811 		case IPV6_TCLASS:
   2812 		case IPV6_PREFER_TEMPADDR: /* XXX not an RFC3542 option */
   2813 			return (ENOPROTOOPT);
   2814 		}
   2815 	}
   2816 
   2817 	switch (optname) {
   2818 #ifdef RFC2292
   2819 	case IPV6_2292PKTINFO:
   2820 #endif
   2821 	case IPV6_PKTINFO:
   2822 	{
   2823 		struct in6_pktinfo *pktinfo;
   2824 
   2825 		if (len != sizeof(struct in6_pktinfo))
   2826 			return (EINVAL);
   2827 
   2828 		pktinfo = (struct in6_pktinfo *)buf;
   2829 
   2830 		/*
   2831 		 * An application can clear any sticky IPV6_PKTINFO option by
   2832 		 * doing a "regular" setsockopt with ipi6_addr being
   2833 		 * in6addr_any and ipi6_ifindex being zero.
   2834 		 * [RFC 3542, Section 6]
   2835 		 */
   2836 		if (optname == IPV6_PKTINFO && opt->ip6po_pktinfo &&
   2837 		    pktinfo->ipi6_ifindex == 0 &&
   2838 		    IN6_IS_ADDR_UNSPECIFIED(&pktinfo->ipi6_addr)) {
   2839 			ip6_clearpktopts(opt, optname);
   2840 			break;
   2841 		}
   2842 
   2843 		if (uproto == IPPROTO_TCP && optname == IPV6_PKTINFO &&
   2844 		    sticky && !IN6_IS_ADDR_UNSPECIFIED(&pktinfo->ipi6_addr)) {
   2845 			return (EINVAL);
   2846 		}
   2847 
   2848 		/* Validate the interface index if specified. */
   2849 		if (pktinfo->ipi6_ifindex) {
   2850 			struct ifnet *ifp;
   2851 			int s = pserialize_read_enter();
   2852 			ifp = if_byindex(pktinfo->ipi6_ifindex);
   2853 			if (ifp == NULL) {
   2854 				pserialize_read_exit(s);
   2855 				return ENXIO;
   2856 			}
   2857 			pserialize_read_exit(s);
   2858 		}
   2859 
   2860 		/*
   2861 		 * We store the address anyway, and let in6_selectsrc()
   2862 		 * validate the specified address.  This is because ipi6_addr
   2863 		 * may not have enough information about its scope zone, and
   2864 		 * we may need additional information (such as outgoing
   2865 		 * interface or the scope zone of a destination address) to
   2866 		 * disambiguate the scope.
   2867 		 * XXX: the delay of the validation may confuse the
   2868 		 * application when it is used as a sticky option.
   2869 		 */
   2870 		if (opt->ip6po_pktinfo == NULL) {
   2871 			opt->ip6po_pktinfo = malloc(sizeof(*pktinfo),
   2872 			    M_IP6OPT, M_NOWAIT);
   2873 			if (opt->ip6po_pktinfo == NULL)
   2874 				return (ENOBUFS);
   2875 		}
   2876 		memcpy(opt->ip6po_pktinfo, pktinfo, sizeof(*pktinfo));
   2877 		break;
   2878 	}
   2879 
   2880 #ifdef RFC2292
   2881 	case IPV6_2292HOPLIMIT:
   2882 #endif
   2883 	case IPV6_HOPLIMIT:
   2884 	{
   2885 		int *hlimp;
   2886 
   2887 		/*
   2888 		 * RFC 3542 deprecated the usage of sticky IPV6_HOPLIMIT
   2889 		 * to simplify the ordering among hoplimit options.
   2890 		 */
   2891 		if (optname == IPV6_HOPLIMIT && sticky)
   2892 			return (ENOPROTOOPT);
   2893 
   2894 		if (len != sizeof(int))
   2895 			return (EINVAL);
   2896 		hlimp = (int *)buf;
   2897 		if (*hlimp < -1 || *hlimp > 255)
   2898 			return (EINVAL);
   2899 
   2900 		opt->ip6po_hlim = *hlimp;
   2901 		break;
   2902 	}
   2903 
   2904 	case IPV6_OTCLASS:
   2905 		if (len != sizeof(u_int8_t))
   2906 			return (EINVAL);
   2907 
   2908 		opt->ip6po_tclass = *(u_int8_t *)buf;
   2909 		break;
   2910 
   2911 	case IPV6_TCLASS:
   2912 	{
   2913 		int tclass;
   2914 
   2915 		if (len != sizeof(int))
   2916 			return (EINVAL);
   2917 		tclass = *(int *)buf;
   2918 		if (tclass < -1 || tclass > 255)
   2919 			return (EINVAL);
   2920 
   2921 		opt->ip6po_tclass = tclass;
   2922 		break;
   2923 	}
   2924 
   2925 #ifdef RFC2292
   2926 	case IPV6_2292NEXTHOP:
   2927 #endif
   2928 	case IPV6_NEXTHOP:
   2929 		error = kauth_authorize_network(cred, KAUTH_NETWORK_IPV6,
   2930 		    KAUTH_REQ_NETWORK_IPV6_HOPBYHOP, NULL, NULL, NULL);
   2931 		if (error)
   2932 			return (error);
   2933 
   2934 		if (len == 0) {	/* just remove the option */
   2935 			ip6_clearpktopts(opt, IPV6_NEXTHOP);
   2936 			break;
   2937 		}
   2938 
   2939 		/* check if cmsg_len is large enough for sa_len */
   2940 		if (len < sizeof(struct sockaddr) || len < *buf)
   2941 			return (EINVAL);
   2942 
   2943 		switch (((struct sockaddr *)buf)->sa_family) {
   2944 		case AF_INET6:
   2945 		{
   2946 			struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)buf;
   2947 
   2948 			if (sa6->sin6_len != sizeof(struct sockaddr_in6))
   2949 				return (EINVAL);
   2950 
   2951 			if (IN6_IS_ADDR_UNSPECIFIED(&sa6->sin6_addr) ||
   2952 			    IN6_IS_ADDR_MULTICAST(&sa6->sin6_addr)) {
   2953 				return (EINVAL);
   2954 			}
   2955 			if ((error = sa6_embedscope(sa6, ip6_use_defzone))
   2956 			    != 0) {
   2957 				return (error);
   2958 			}
   2959 			break;
   2960 		}
   2961 		case AF_LINK:	/* eventually be supported? */
   2962 		default:
   2963 			return (EAFNOSUPPORT);
   2964 		}
   2965 
   2966 		/* turn off the previous option, then set the new option. */
   2967 		ip6_clearpktopts(opt, IPV6_NEXTHOP);
   2968 		opt->ip6po_nexthop = malloc(*buf, M_IP6OPT, M_NOWAIT);
   2969 		if (opt->ip6po_nexthop == NULL)
   2970 			return (ENOBUFS);
   2971 		memcpy(opt->ip6po_nexthop, buf, *buf);
   2972 		break;
   2973 
   2974 #ifdef RFC2292
   2975 	case IPV6_2292HOPOPTS:
   2976 #endif
   2977 	case IPV6_HOPOPTS:
   2978 	{
   2979 		struct ip6_hbh *hbh;
   2980 		int hbhlen;
   2981 
   2982 		/*
   2983 		 * XXX: We don't allow a non-privileged user to set ANY HbH
   2984 		 * options, since per-option restriction has too much
   2985 		 * overhead.
   2986 		 */
   2987 		error = kauth_authorize_network(cred, KAUTH_NETWORK_IPV6,
   2988 		    KAUTH_REQ_NETWORK_IPV6_HOPBYHOP, NULL, NULL, NULL);
   2989 		if (error)
   2990 			return (error);
   2991 
   2992 		if (len == 0) {
   2993 			ip6_clearpktopts(opt, IPV6_HOPOPTS);
   2994 			break;	/* just remove the option */
   2995 		}
   2996 
   2997 		/* message length validation */
   2998 		if (len < sizeof(struct ip6_hbh))
   2999 			return (EINVAL);
   3000 		hbh = (struct ip6_hbh *)buf;
   3001 		hbhlen = (hbh->ip6h_len + 1) << 3;
   3002 		if (len != hbhlen)
   3003 			return (EINVAL);
   3004 
   3005 		/* turn off the previous option, then set the new option. */
   3006 		ip6_clearpktopts(opt, IPV6_HOPOPTS);
   3007 		opt->ip6po_hbh = malloc(hbhlen, M_IP6OPT, M_NOWAIT);
   3008 		if (opt->ip6po_hbh == NULL)
   3009 			return (ENOBUFS);
   3010 		memcpy(opt->ip6po_hbh, hbh, hbhlen);
   3011 
   3012 		break;
   3013 	}
   3014 
   3015 #ifdef RFC2292
   3016 	case IPV6_2292DSTOPTS:
   3017 #endif
   3018 	case IPV6_DSTOPTS:
   3019 	case IPV6_RTHDRDSTOPTS:
   3020 	{
   3021 		struct ip6_dest *dest, **newdest = NULL;
   3022 		int destlen;
   3023 
   3024 		/* XXX: see the comment for IPV6_HOPOPTS */
   3025 		error = kauth_authorize_network(cred, KAUTH_NETWORK_IPV6,
   3026 		    KAUTH_REQ_NETWORK_IPV6_HOPBYHOP, NULL, NULL, NULL);
   3027 		if (error)
   3028 			return (error);
   3029 
   3030 		if (len == 0) {
   3031 			ip6_clearpktopts(opt, optname);
   3032 			break;	/* just remove the option */
   3033 		}
   3034 
   3035 		/* message length validation */
   3036 		if (len < sizeof(struct ip6_dest))
   3037 			return (EINVAL);
   3038 		dest = (struct ip6_dest *)buf;
   3039 		destlen = (dest->ip6d_len + 1) << 3;
   3040 		if (len != destlen)
   3041 			return (EINVAL);
   3042 		/*
   3043 		 * Determine the position that the destination options header
   3044 		 * should be inserted; before or after the routing header.
   3045 		 */
   3046 		switch (optname) {
   3047 		case IPV6_2292DSTOPTS:
   3048 			/*
   3049 			 * The old advanced API is ambiguous on this point.
   3050 			 * Our approach is to determine the position based
   3051 			 * according to the existence of a routing header.
   3052 			 * Note, however, that this depends on the order of the
   3053 			 * extension headers in the ancillary data; the 1st
   3054 			 * part of the destination options header must appear
   3055 			 * before the routing header in the ancillary data,
   3056 			 * too.
   3057 			 * RFC3542 solved the ambiguity by introducing
   3058 			 * separate ancillary data or option types.
   3059 			 */
   3060 			if (opt->ip6po_rthdr == NULL)
   3061 				newdest = &opt->ip6po_dest1;
   3062 			else
   3063 				newdest = &opt->ip6po_dest2;
   3064 			break;
   3065 		case IPV6_RTHDRDSTOPTS:
   3066 			newdest = &opt->ip6po_dest1;
   3067 			break;
   3068 		case IPV6_DSTOPTS:
   3069 			newdest = &opt->ip6po_dest2;
   3070 			break;
   3071 		}
   3072 
   3073 		/* turn off the previous option, then set the new option. */
   3074 		ip6_clearpktopts(opt, optname);
   3075 		*newdest = malloc(destlen, M_IP6OPT, M_NOWAIT);
   3076 		if (*newdest == NULL)
   3077 			return (ENOBUFS);
   3078 		memcpy(*newdest, dest, destlen);
   3079 
   3080 		break;
   3081 	}
   3082 
   3083 #ifdef RFC2292
   3084 	case IPV6_2292RTHDR:
   3085 #endif
   3086 	case IPV6_RTHDR:
   3087 	{
   3088 		struct ip6_rthdr *rth;
   3089 		int rthlen;
   3090 
   3091 		if (len == 0) {
   3092 			ip6_clearpktopts(opt, IPV6_RTHDR);
   3093 			break;	/* just remove the option */
   3094 		}
   3095 
   3096 		/* message length validation */
   3097 		if (len < sizeof(struct ip6_rthdr))
   3098 			return (EINVAL);
   3099 		rth = (struct ip6_rthdr *)buf;
   3100 		rthlen = (rth->ip6r_len + 1) << 3;
   3101 		if (len != rthlen)
   3102 			return (EINVAL);
   3103 		switch (rth->ip6r_type) {
   3104 		case IPV6_RTHDR_TYPE_0:
   3105 			if (rth->ip6r_len == 0)	/* must contain one addr */
   3106 				return (EINVAL);
   3107 			if (rth->ip6r_len % 2) /* length must be even */
   3108 				return (EINVAL);
   3109 			if (rth->ip6r_len / 2 != rth->ip6r_segleft)
   3110 				return (EINVAL);
   3111 			break;
   3112 		default:
   3113 			return (EINVAL);	/* not supported */
   3114 		}
   3115 		/* turn off the previous option */
   3116 		ip6_clearpktopts(opt, IPV6_RTHDR);
   3117 		opt->ip6po_rthdr = malloc(rthlen, M_IP6OPT, M_NOWAIT);
   3118 		if (opt->ip6po_rthdr == NULL)
   3119 			return (ENOBUFS);
   3120 		memcpy(opt->ip6po_rthdr, rth, rthlen);
   3121 		break;
   3122 	}
   3123 
   3124 	case IPV6_USE_MIN_MTU:
   3125 		if (len != sizeof(int))
   3126 			return (EINVAL);
   3127 		minmtupolicy = *(int *)buf;
   3128 		if (minmtupolicy != IP6PO_MINMTU_MCASTONLY &&
   3129 		    minmtupolicy != IP6PO_MINMTU_DISABLE &&
   3130 		    minmtupolicy != IP6PO_MINMTU_ALL) {
   3131 			return (EINVAL);
   3132 		}
   3133 		opt->ip6po_minmtu = minmtupolicy;
   3134 		break;
   3135 
   3136 	case IPV6_DONTFRAG:
   3137 		if (len != sizeof(int))
   3138 			return (EINVAL);
   3139 
   3140 		if (uproto == IPPROTO_TCP || *(int *)buf == 0) {
   3141 			/*
   3142 			 * we ignore this option for TCP sockets.
   3143 			 * (RFC3542 leaves this case unspecified.)
   3144 			 */
   3145 			opt->ip6po_flags &= ~IP6PO_DONTFRAG;
   3146 		} else
   3147 			opt->ip6po_flags |= IP6PO_DONTFRAG;
   3148 		break;
   3149 
   3150 	case IPV6_PREFER_TEMPADDR:
   3151 	{
   3152 		int preftemp;
   3153 
   3154 		if (len != sizeof(int))
   3155 			return (EINVAL);
   3156 		preftemp = *(int *)buf;
   3157 		switch (preftemp) {
   3158 		case IP6PO_TEMPADDR_SYSTEM:
   3159 		case IP6PO_TEMPADDR_NOTPREFER:
   3160 		case IP6PO_TEMPADDR_PREFER:
   3161 			break;
   3162 		default:
   3163 			return (EINVAL);
   3164 		}
   3165 		opt->ip6po_prefer_tempaddr = preftemp;
   3166 		break;
   3167 	}
   3168 
   3169 	default:
   3170 		return (ENOPROTOOPT);
   3171 	} /* end of switch */
   3172 
   3173 	return (0);
   3174 }
   3175 
   3176 /*
   3177  * Routine called from ip6_output() to loop back a copy of an IP6 multicast
   3178  * packet to the input queue of a specified interface.  Note that this
   3179  * calls the output routine of the loopback "driver", but with an interface
   3180  * pointer that might NOT be lo0ifp -- easier than replicating that code here.
   3181  */
   3182 void
   3183 ip6_mloopback(struct ifnet *ifp, struct mbuf *m,
   3184 	const struct sockaddr_in6 *dst)
   3185 {
   3186 	struct mbuf *copym;
   3187 	struct ip6_hdr *ip6;
   3188 
   3189 	copym = m_copy(m, 0, M_COPYALL);
   3190 	if (copym == NULL)
   3191 		return;
   3192 
   3193 	/*
   3194 	 * Make sure to deep-copy IPv6 header portion in case the data
   3195 	 * is in an mbuf cluster, so that we can safely override the IPv6
   3196 	 * header portion later.
   3197 	 */
   3198 	if ((copym->m_flags & M_EXT) != 0 ||
   3199 	    copym->m_len < sizeof(struct ip6_hdr)) {
   3200 		copym = m_pullup(copym, sizeof(struct ip6_hdr));
   3201 		if (copym == NULL)
   3202 			return;
   3203 	}
   3204 
   3205 #ifdef DIAGNOSTIC
   3206 	if (copym->m_len < sizeof(*ip6)) {
   3207 		m_freem(copym);
   3208 		return;
   3209 	}
   3210 #endif
   3211 
   3212 	ip6 = mtod(copym, struct ip6_hdr *);
   3213 	/*
   3214 	 * clear embedded scope identifiers if necessary.
   3215 	 * in6_clearscope will touch the addresses only when necessary.
   3216 	 */
   3217 	in6_clearscope(&ip6->ip6_src);
   3218 	in6_clearscope(&ip6->ip6_dst);
   3219 
   3220 	(void)looutput(ifp, copym, (const struct sockaddr *)dst, NULL);
   3221 }
   3222 
   3223 /*
   3224  * Chop IPv6 header off from the payload.
   3225  */
   3226 static int
   3227 ip6_splithdr(struct mbuf *m,  struct ip6_exthdrs *exthdrs)
   3228 {
   3229 	struct mbuf *mh;
   3230 	struct ip6_hdr *ip6;
   3231 
   3232 	ip6 = mtod(m, struct ip6_hdr *);
   3233 	if (m->m_len > sizeof(*ip6)) {
   3234 		MGETHDR(mh, M_DONTWAIT, MT_HEADER);
   3235 		if (mh == 0) {
   3236 			m_freem(m);
   3237 			return ENOBUFS;
   3238 		}
   3239 		M_MOVE_PKTHDR(mh, m);
   3240 		MH_ALIGN(mh, sizeof(*ip6));
   3241 		m->m_len -= sizeof(*ip6);
   3242 		m->m_data += sizeof(*ip6);
   3243 		mh->m_next = m;
   3244 		m = mh;
   3245 		m->m_len = sizeof(*ip6);
   3246 		bcopy((void *)ip6, mtod(m, void *), sizeof(*ip6));
   3247 	}
   3248 	exthdrs->ip6e_ip6 = m;
   3249 	return 0;
   3250 }
   3251 
   3252 /*
   3253  * Compute IPv6 extension header length.
   3254  */
   3255 int
   3256 ip6_optlen(struct in6pcb *in6p)
   3257 {
   3258 	int len;
   3259 
   3260 	if (!in6p->in6p_outputopts)
   3261 		return 0;
   3262 
   3263 	len = 0;
   3264 #define elen(x) \
   3265     (((struct ip6_ext *)(x)) ? (((struct ip6_ext *)(x))->ip6e_len + 1) << 3 : 0)
   3266 
   3267 	len += elen(in6p->in6p_outputopts->ip6po_hbh);
   3268 	len += elen(in6p->in6p_outputopts->ip6po_dest1);
   3269 	len += elen(in6p->in6p_outputopts->ip6po_rthdr);
   3270 	len += elen(in6p->in6p_outputopts->ip6po_dest2);
   3271 	return len;
   3272 #undef elen
   3273 }
   3274 
   3275 /*
   3276  * Ensure sending address is valid.
   3277  * Returns 0 on success, -1 if an error should be sent back or 1
   3278  * if the packet could be dropped without error (protocol dependent).
   3279  */
   3280 static int
   3281 ip6_ifaddrvalid(const struct in6_addr *addr)
   3282 {
   3283 	struct sockaddr_in6 sin6;
   3284 	int s, error;
   3285 	struct ifaddr *ifa;
   3286 	struct in6_ifaddr *ia6;
   3287 
   3288 	if (IN6_IS_ADDR_UNSPECIFIED(addr))
   3289 		return 0;
   3290 
   3291 	memset(&sin6, 0, sizeof(sin6));
   3292 	sin6.sin6_family = AF_INET6;
   3293 	sin6.sin6_len = sizeof(sin6);
   3294 	sin6.sin6_addr = *addr;
   3295 
   3296 	s = pserialize_read_enter();
   3297 	ifa = ifa_ifwithaddr(sin6tosa(&sin6));
   3298 	if ((ia6 = ifatoia6(ifa)) == NULL ||
   3299 	    ia6->ia6_flags & (IN6_IFF_ANYCAST | IN6_IFF_DUPLICATED))
   3300 		error = -1;
   3301 	else if (ia6->ia6_flags & (IN6_IFF_TENTATIVE | IN6_IFF_DETACHED))
   3302 		error = 1;
   3303 	else
   3304 		error = 0;
   3305 	pserialize_read_exit(s);
   3306 
   3307 	return error;
   3308 }
   3309