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ipsec_output.c revision 1.5
      1 /*	$NetBSD: ipsec_output.c,v 1.5 2003/08/22 21:53:10 itojun Exp $	*/
      2 /*	$FreeBSD: src/sys/netipsec/ipsec_output.c,v 1.3.2.1 2003/01/24 05:11:35 sam Exp $	*/
      3 /*	$KAME: ipsec.c,v 1.103 2001/05/24 07:14:18 sakane Exp $	*/
      4 
      5 #include <sys/cdefs.h>
      6 __KERNEL_RCSID(0, "$NetBSD: ipsec_output.c,v 1.5 2003/08/22 21:53:10 itojun Exp $");
      7 
      8 /*
      9  * IPsec output processing.
     10  */
     11 #include "opt_inet.h"
     12 #ifdef __FreeBSD__
     13 #include "opt_inet6.h"
     14 #endif
     15 #include "opt_ipsec.h"
     16 
     17 #include <sys/param.h>
     18 #include <sys/systm.h>
     19 #include <sys/mbuf.h>
     20 #include <sys/domain.h>
     21 #include <sys/protosw.h>
     22 #include <sys/socket.h>
     23 #include <sys/errno.h>
     24 #include <sys/syslog.h>
     25 
     26 #include <net/if.h>
     27 #include <net/route.h>
     28 
     29 #include <netinet/in.h>
     30 #include <netinet/in_systm.h>
     31 #include <netinet/ip.h>
     32 #include <netinet/ip_var.h>
     33 #include <netinet/in_var.h>
     34 #include <netinet/ip_ecn.h>
     35 #ifdef INET6
     36 #include <netinet6/ip6_ecn.h>
     37 #endif
     38 
     39 #include <netinet/ip6.h>
     40 #ifdef INET6
     41 #include <netinet6/ip6_var.h>
     42 #endif
     43 #include <netinet/in_pcb.h>
     44 #ifdef INET6
     45 #include <netinet/icmp6.h>
     46 #endif
     47 
     48 #include <netipsec/ipsec.h>
     49 #ifdef INET6
     50 #include <netipsec/ipsec6.h>
     51 #endif
     52 #include <netipsec/ah_var.h>
     53 #include <netipsec/esp_var.h>
     54 #include <netipsec/ipcomp_var.h>
     55 
     56 #include <netipsec/xform.h>
     57 
     58 #include <netipsec/key.h>
     59 #include <netipsec/keydb.h>
     60 #include <netipsec/key_debug.h>
     61 #include <netipsec/ipsec_osdep.h>
     62 
     63 int
     64 ipsec_process_done(struct mbuf *m, struct ipsecrequest *isr)
     65 {
     66 	struct tdb_ident *tdbi;
     67 	struct m_tag *mtag;
     68 	struct secasvar *sav;
     69 	struct secasindex *saidx;
     70 	int error;
     71 
     72 	IPSEC_SPLASSERT_SOFTNET("ipsec_process_done");
     73 
     74 	IPSEC_ASSERT(m != NULL, ("ipsec_process_done: null mbuf"));
     75 	IPSEC_ASSERT(isr != NULL, ("ipsec_process_done: null ISR"));
     76 	sav = isr->sav;
     77 	IPSEC_ASSERT(sav != NULL, ("ipsec_process_done: null SA"));
     78 	IPSEC_ASSERT(sav->sah != NULL, ("ipsec_process_done: null SAH"));
     79 
     80 	saidx = &sav->sah->saidx;
     81 	switch (saidx->dst.sa.sa_family) {
     82 #ifdef INET
     83 	case AF_INET:
     84 		/* Fix the header length, for AH processing. */
     85 		mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
     86 		break;
     87 #endif /* INET */
     88 #ifdef INET6
     89 	case AF_INET6:
     90 		/* Fix the header length, for AH processing. */
     91 		if (m->m_pkthdr.len < sizeof (struct ip6_hdr)) {
     92 			error = ENXIO;
     93 			goto bad;
     94 		}
     95 		if (m->m_pkthdr.len - sizeof (struct ip6_hdr) > IPV6_MAXPACKET) {
     96 			/* No jumbogram support. */
     97 			error = ENXIO;	/*?*/
     98 			goto bad;
     99 		}
    100 		mtod(m, struct ip6_hdr *)->ip6_plen =
    101 			htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
    102 		break;
    103 #endif /* INET6 */
    104 	default:
    105 		DPRINTF(("ipsec_process_done: unknown protocol family %u\n",
    106 		    saidx->dst.sa.sa_family));
    107 		error = ENXIO;
    108 		goto bad;
    109 	}
    110 
    111 	/*
    112 	 * Add a record of what we've done or what needs to be done to the
    113 	 * packet.
    114 	 */
    115 	mtag = m_tag_get(PACKET_TAG_IPSEC_OUT_DONE,
    116 			sizeof(struct tdb_ident), M_NOWAIT);
    117 	if (mtag == NULL) {
    118 		DPRINTF(("ipsec_process_done: could not get packet tag\n"));
    119 		error = ENOMEM;
    120 		goto bad;
    121 	}
    122 
    123 	tdbi = (struct tdb_ident *)(mtag + 1);
    124 	tdbi->dst = saidx->dst;
    125 	tdbi->proto = saidx->proto;
    126 	tdbi->spi = sav->spi;
    127 	m_tag_prepend(m, mtag);
    128 
    129 	/*
    130 	 * If there's another (bundled) SA to apply, do so.
    131 	 * Note that this puts a burden on the kernel stack size.
    132 	 * If this is a problem we'll need to introduce a queue
    133 	 * to set the packet on so we can unwind the stack before
    134 	 * doing further processing.
    135 	 */
    136 	if (isr->next) {
    137 		newipsecstat.ips_out_bundlesa++;
    138 		return ipsec4_process_packet(m, isr->next, 0, 0);
    139 	}
    140 
    141 	/*
    142 	 * We're done with IPsec processing, transmit the packet using the
    143 	 * appropriate network protocol (IP or IPv6). SPD lookup will be
    144 	 * performed again there.
    145 	 */
    146 	switch (saidx->dst.sa.sa_family) {
    147 #ifdef INET
    148 	struct ip *ip;
    149 	case AF_INET:
    150 		ip = mtod(m, struct ip *);
    151 #ifdef __FreeBSD__
    152 		/* FreeBSD ip_output() expects ip_len, ip_off in host endian */
    153 		ip->ip_len = ntohs(ip->ip_len);
    154 		ip->ip_off = ntohs(ip->ip_off);
    155 #endif /* __FreeBSD_ */
    156 		return ip_output(m, NULL, NULL, IP_RAWOUTPUT,
    157 		    (struct ip_moptions *)NULL, (struct socket *)NULL);
    158 
    159 #endif /* INET */
    160 #ifdef INET6
    161 	case AF_INET6:
    162 		/*
    163 		 * We don't need massage, IPv6 header fields are always in
    164 		 * net endian.
    165 		 */
    166 		return ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
    167 #endif /* INET6 */
    168 	}
    169 	panic("ipsec_process_done");
    170 bad:
    171 	m_freem(m);
    172 	KEY_FREESAV(&sav);
    173 	return (error);
    174 }
    175 
    176 static struct ipsecrequest *
    177 ipsec_nextisr(
    178 	struct mbuf *m,
    179 	struct ipsecrequest *isr,
    180 	int af,
    181 	struct secasindex *saidx,
    182 	int *error
    183 )
    184 {
    185 #define IPSEC_OSTAT(x,y,z) (isr->saidx.proto == IPPROTO_ESP ? (x)++ : \
    186 			    isr->saidx.proto == IPPROTO_AH ? (y)++ : (z)++)
    187 	struct secasvar *sav;
    188 
    189 	IPSEC_SPLASSERT_SOFTNET("ipsec_nextisr");
    190 	IPSEC_ASSERT(af == AF_INET || af == AF_INET6,
    191 		("ipsec_nextisr: invalid address family %u", af));
    192 again:
    193 	/*
    194 	 * Craft SA index to search for proper SA.  Note that
    195 	 * we only fillin unspecified SA peers for transport
    196 	 * mode; for tunnel mode they must already be filled in.
    197 	 */
    198 	*saidx = isr->saidx;
    199 	if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) {
    200 		/* Fillin unspecified SA peers only for transport mode */
    201 		if (af == AF_INET) {
    202 			struct sockaddr_in *sin;
    203 			struct ip *ip = mtod(m, struct ip *);
    204 
    205 			if (saidx->src.sa.sa_len == 0) {
    206 				sin = &saidx->src.sin;
    207 				sin->sin_len = sizeof(*sin);
    208 				sin->sin_family = AF_INET;
    209 				sin->sin_port = IPSEC_PORT_ANY;
    210 				sin->sin_addr = ip->ip_src;
    211 			}
    212 			if (saidx->dst.sa.sa_len == 0) {
    213 				sin = &saidx->dst.sin;
    214 				sin->sin_len = sizeof(*sin);
    215 				sin->sin_family = AF_INET;
    216 				sin->sin_port = IPSEC_PORT_ANY;
    217 				sin->sin_addr = ip->ip_dst;
    218 			}
    219 		} else {
    220 			struct sockaddr_in6 *sin6;
    221 			struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
    222 
    223 			if (saidx->src.sin6.sin6_len == 0) {
    224 				sin6 = (struct sockaddr_in6 *)&saidx->src;
    225 				sin6->sin6_len = sizeof(*sin6);
    226 				sin6->sin6_family = AF_INET6;
    227 				sin6->sin6_port = IPSEC_PORT_ANY;
    228 				sin6->sin6_addr = ip6->ip6_src;
    229 				if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) {
    230 					/* fix scope id for comparing SPD */
    231 					sin6->sin6_addr.s6_addr16[1] = 0;
    232 					sin6->sin6_scope_id =
    233 					    ntohs(ip6->ip6_src.s6_addr16[1]);
    234 				}
    235 			}
    236 			if (saidx->dst.sin6.sin6_len == 0) {
    237 				sin6 = (struct sockaddr_in6 *)&saidx->dst;
    238 				sin6->sin6_len = sizeof(*sin6);
    239 				sin6->sin6_family = AF_INET6;
    240 				sin6->sin6_port = IPSEC_PORT_ANY;
    241 				sin6->sin6_addr = ip6->ip6_dst;
    242 				if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) {
    243 					/* fix scope id for comparing SPD */
    244 					sin6->sin6_addr.s6_addr16[1] = 0;
    245 					sin6->sin6_scope_id =
    246 					    ntohs(ip6->ip6_dst.s6_addr16[1]);
    247 				}
    248 			}
    249 		}
    250 	}
    251 
    252 	/*
    253 	 * Lookup SA and validate it.
    254 	 */
    255 	*error = key_checkrequest(isr, saidx);
    256 	if (*error != 0) {
    257 		/*
    258 		 * IPsec processing is required, but no SA found.
    259 		 * I assume that key_acquire() had been called
    260 		 * to get/establish the SA. Here I discard
    261 		 * this packet because it is responsibility for
    262 		 * upper layer to retransmit the packet.
    263 		 */
    264 		newipsecstat.ips_out_nosa++;
    265 		goto bad;
    266 	}
    267 	sav = isr->sav;
    268 	if (sav == NULL) {		/* XXX valid return */
    269 		IPSEC_ASSERT(ipsec_get_reqlevel(isr) == IPSEC_LEVEL_USE,
    270 			("ipsec_nextisr: no SA found, but required; level %u",
    271 			ipsec_get_reqlevel(isr)));
    272 		isr = isr->next;
    273 		if (isr == NULL) {
    274 			/*XXXstatistic??*/
    275 			*error = EINVAL;		/*XXX*/
    276 			return isr;
    277 		}
    278 		goto again;
    279 	}
    280 
    281 	/*
    282 	 * Check system global policy controls.
    283 	 */
    284 	if ((isr->saidx.proto == IPPROTO_ESP && !esp_enable) ||
    285 	    (isr->saidx.proto == IPPROTO_AH && !ah_enable) ||
    286 	    (isr->saidx.proto == IPPROTO_IPCOMP && !ipcomp_enable)) {
    287 		DPRINTF(("ipsec_nextisr: IPsec outbound packet dropped due"
    288 			" to policy (check your sysctls)\n"));
    289 		IPSEC_OSTAT(espstat.esps_pdrops, ahstat.ahs_pdrops,
    290 		    ipcompstat.ipcomps_pdrops);
    291 		*error = EHOSTUNREACH;
    292 		goto bad;
    293 	}
    294 
    295 	/*
    296 	 * Sanity check the SA contents for the caller
    297 	 * before they invoke the xform output method.
    298 	 */
    299 	if (sav->tdb_xform == NULL) {
    300 		DPRINTF(("ipsec_nextisr: no transform for SA\n"));
    301 		IPSEC_OSTAT(espstat.esps_noxform, ahstat.ahs_noxform,
    302 		    ipcompstat.ipcomps_noxform);
    303 		*error = EHOSTUNREACH;
    304 		goto bad;
    305 	}
    306 	return isr;
    307 bad:
    308 	IPSEC_ASSERT(*error != 0, ("ipsec_nextisr: error return w/ no error code"));
    309 	return NULL;
    310 #undef IPSEC_OSTAT
    311 }
    312 
    313 #ifdef INET
    314 /*
    315  * IPsec output logic for IPv4.
    316  */
    317 int
    318 ipsec4_process_packet(
    319 	struct mbuf *m,
    320 	struct ipsecrequest *isr,
    321 	int flags,
    322 	int tunalready)
    323 {
    324 	struct secasindex saidx;
    325 	struct secasvar *sav;
    326 	struct ip *ip;
    327 	int s, error, i, off;
    328 
    329 	IPSEC_ASSERT(m != NULL, ("ipsec4_process_packet: null mbuf"));
    330 	IPSEC_ASSERT(isr != NULL, ("ipsec4_process_packet: null isr"));
    331 
    332 	s = splsoftnet();			/* insure SA contents don't change */
    333 
    334 	isr = ipsec_nextisr(m, isr, AF_INET, &saidx, &error);
    335 	if (isr == NULL)
    336 		goto bad;
    337 
    338 	sav = isr->sav;
    339 	if (!tunalready) {
    340 		union sockaddr_union *dst = &sav->sah->saidx.dst;
    341 		int setdf;
    342 
    343 		/*
    344 		 * Collect IP_DF state from the outer header.
    345 		 */
    346 		if (dst->sa.sa_family == AF_INET) {
    347 			if (m->m_len < sizeof (struct ip) &&
    348 			    (m = m_pullup(m, sizeof (struct ip))) == NULL) {
    349 				error = ENOBUFS;
    350 				goto bad;
    351 			}
    352 			ip = mtod(m, struct ip *);
    353 			/* Honor system-wide control of how to handle IP_DF */
    354 			switch (ip4_ipsec_dfbit) {
    355 			case 0:			/* clear in outer header */
    356 			case 1:			/* set in outer header */
    357 				setdf = ip4_ipsec_dfbit;
    358 				break;
    359 			default:		/* propagate to outer header */
    360 				setdf = ip->ip_off;
    361 #ifndef __FreeBSD__
    362 		/* On FreeBSD, ip_off and ip_len assumed in host endian. */
    363 				setdf = ntohs(setdf);
    364 #endif
    365 				setdf = htons(setdf & IP_DF);
    366 				break;
    367 			}
    368 		} else {
    369 			ip = NULL;		/* keep compiler happy */
    370 			setdf = 0;
    371 		}
    372 		/* Do the appropriate encapsulation, if necessary */
    373 		if (isr->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
    374 		    dst->sa.sa_family != AF_INET ||	    /* PF mismatch */
    375 #if 0
    376 		    (sav->flags & SADB_X_SAFLAGS_TUNNEL) || /* Tunnel requ'd */
    377 		    sav->tdb_xform->xf_type == XF_IP4 ||    /* ditto */
    378 #endif
    379 		    (dst->sa.sa_family == AF_INET &&	    /* Proxy */
    380 		     dst->sin.sin_addr.s_addr != INADDR_ANY &&
    381 		     dst->sin.sin_addr.s_addr != ip->ip_dst.s_addr)) {
    382 			struct mbuf *mp;
    383 
    384 			/* Fix IPv4 header checksum and length */
    385 			if (m->m_len < sizeof (struct ip) &&
    386 			    (m = m_pullup(m, sizeof (struct ip))) == NULL) {
    387 				error = ENOBUFS;
    388 				goto bad;
    389 			}
    390 			ip = mtod(m, struct ip *);
    391 			ip->ip_len = htons(m->m_pkthdr.len);
    392 			ip->ip_sum = 0;
    393 #ifdef _IP_VHL
    394 			if (ip->ip_vhl == IP_VHL_BORING)
    395 				ip->ip_sum = in_cksum_hdr(ip);
    396 			else
    397 				ip->ip_sum = in_cksum(m,
    398 					_IP_VHL_HL(ip->ip_vhl) << 2);
    399 #else
    400 			ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
    401 #endif
    402 
    403 			/* Encapsulate the packet */
    404 			error = ipip_output(m, isr, &mp, 0, 0);
    405 			if (mp == NULL && !error) {
    406 				/* Should never happen. */
    407 				DPRINTF(("ipsec4_process_packet: ipip_output "
    408 					"returns no mbuf and no error!"));
    409 				error = EFAULT;
    410 			}
    411 			if (error) {
    412 				if (mp)
    413 					m_freem(mp);
    414 				goto bad;
    415 			}
    416 			m = mp, mp = NULL;
    417 			/*
    418 			 * ipip_output clears IP_DF in the new header.  If
    419 			 * we need to propagate IP_DF from the outer header,
    420 			 * then we have to do it here.
    421 			 *
    422 			 * XXX shouldn't assume what ipip_output does.
    423 			 */
    424 			if (dst->sa.sa_family == AF_INET && setdf) {
    425 				if (m->m_len < sizeof (struct ip) &&
    426 				    (m = m_pullup(m, sizeof (struct ip))) == NULL) {
    427 					error = ENOBUFS;
    428 					goto bad;
    429 				}
    430 				ip = mtod(m, struct ip *);
    431 				ip->ip_off = ntohs(ip->ip_off);
    432 				ip->ip_off |= IP_DF;
    433 				ip->ip_off = htons(ip->ip_off);
    434 			}
    435 		}
    436 	}
    437 
    438 	/*
    439 	 * Dispatch to the appropriate IPsec transform logic.  The
    440 	 * packet will be returned for transmission after crypto
    441 	 * processing, etc. are completed.  For encapsulation we
    442 	 * bypass this call because of the explicit call done above
    443 	 * (necessary to deal with IP_DF handling for IPv4).
    444 	 *
    445 	 * NB: m & sav are ``passed to caller'' who's reponsible for
    446 	 *     for reclaiming their resources.
    447 	 */
    448 	if (sav->tdb_xform->xf_type != XF_IP4) {
    449 		ip = mtod(m, struct ip *);
    450 		i = ip->ip_hl << 2;
    451 		off = offsetof(struct ip, ip_p);
    452 		error = (*sav->tdb_xform->xf_output)(m, isr, NULL, i, off);
    453 	} else {
    454 		error = ipsec_process_done(m, isr);
    455 	}
    456 	splx(s);
    457 	return error;
    458 bad:
    459 	splx(s);
    460 	if (m)
    461 		m_freem(m);
    462 	return error;
    463 }
    464 #endif
    465 
    466 #ifdef INET6
    467 /*
    468  * Chop IP6 header from the payload.
    469  */
    470 static struct mbuf *
    471 ipsec6_splithdr(struct mbuf *m)
    472 {
    473 	struct mbuf *mh;
    474 	struct ip6_hdr *ip6;
    475 	int hlen;
    476 
    477 	IPSEC_ASSERT(m->m_len >= sizeof (struct ip6_hdr),
    478 		("ipsec6_splithdr: first mbuf too short, len %u", m->m_len));
    479 	ip6 = mtod(m, struct ip6_hdr *);
    480 	hlen = sizeof(struct ip6_hdr);
    481 	if (m->m_len > hlen) {
    482 		MGETHDR(mh, M_DONTWAIT, MT_HEADER);
    483 		if (!mh) {
    484 			m_freem(m);
    485 			return NULL;
    486 		}
    487 		M_MOVE_PKTHDR(mh, m);
    488 		MH_ALIGN(mh, hlen);
    489 		m->m_len -= hlen;
    490 		m->m_data += hlen;
    491 		mh->m_next = m;
    492 		m = mh;
    493 		m->m_len = hlen;
    494 		bcopy((caddr_t)ip6, mtod(m, caddr_t), hlen);
    495 	} else if (m->m_len < hlen) {
    496 		m = m_pullup(m, hlen);
    497 		if (!m)
    498 			return NULL;
    499 	}
    500 	return m;
    501 }
    502 
    503 /*
    504  * IPsec output logic for IPv6, transport mode.
    505  */
    506 int
    507 ipsec6_output_trans(
    508 	struct ipsec_output_state *state,
    509 	u_char *nexthdrp,
    510 	struct mbuf *mprev,
    511 	struct secpolicy *sp,
    512 	int flags,
    513 	int *tun)
    514 {
    515 	struct ipsecrequest *isr;
    516 	struct secasindex saidx;
    517 	int error = 0;
    518 	struct mbuf *m;
    519 
    520 	IPSEC_ASSERT(state != NULL, ("ipsec6_output: null state"));
    521 	IPSEC_ASSERT(state->m != NULL, ("ipsec6_output: null m"));
    522 	IPSEC_ASSERT(nexthdrp != NULL, ("ipsec6_output: null nexthdrp"));
    523 	IPSEC_ASSERT(mprev != NULL, ("ipsec6_output: null mprev"));
    524 	IPSEC_ASSERT(sp != NULL, ("ipsec6_output: null sp"));
    525 	IPSEC_ASSERT(tun != NULL, ("ipsec6_output: null tun"));
    526 
    527 	KEYDEBUG(KEYDEBUG_IPSEC_DATA,
    528 		printf("ipsec6_output_trans: applyed SP\n");
    529 		kdebug_secpolicy(sp));
    530 
    531 	isr = sp->req;
    532 	if (isr->saidx.mode == IPSEC_MODE_TUNNEL) {
    533 		/* the rest will be handled by ipsec6_output_tunnel() */
    534 		*tun = 1;		/* need tunnel-mode processing */
    535 		return 0;
    536 	}
    537 
    538 	*tun = 0;
    539 	m = state->m;
    540 
    541 	isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error);
    542 	if (isr == NULL) {
    543 #ifdef notdef
    544 		/* XXX should notification be done for all errors ? */
    545 		/*
    546 		 * Notify the fact that the packet is discarded
    547 		 * to ourselves. I believe this is better than
    548 		 * just silently discarding. (jinmei (at) kame.net)
    549 		 * XXX: should we restrict the error to TCP packets?
    550 		 * XXX: should we directly notify sockets via
    551 		 *      pfctlinputs?
    552 		 */
    553 		icmp6_error(m, ICMP6_DST_UNREACH,
    554 			    ICMP6_DST_UNREACH_ADMIN, 0);
    555 		m = NULL;	/* NB: icmp6_error frees mbuf */
    556 #endif
    557 		goto bad;
    558 	}
    559 
    560 	return (*isr->sav->tdb_xform->xf_output)(m, isr, NULL,
    561 		sizeof (struct ip6_hdr),
    562 		offsetof(struct ip6_hdr, ip6_nxt));
    563 bad:
    564 	if (m)
    565 		m_freem(m);
    566 	state->m = NULL;
    567 	return error;
    568 }
    569 
    570 static int
    571 ipsec6_encapsulate(struct mbuf *m, struct secasvar *sav)
    572 {
    573 	struct ip6_hdr *oip6;
    574 	struct ip6_hdr *ip6;
    575 	size_t plen;
    576 
    577 	/* can't tunnel between different AFs */
    578 	if (sav->sah->saidx.src.sa.sa_family != AF_INET6 ||
    579 	    sav->sah->saidx.dst.sa.sa_family != AF_INET6) {
    580 		m_freem(m);
    581 		return EINVAL;
    582 	}
    583 	IPSEC_ASSERT(m->m_len != sizeof (struct ip6_hdr),
    584 		("ipsec6_encapsulate: mbuf wrong size; len %u", m->m_len));
    585 
    586 
    587 	/*
    588 	 * grow the mbuf to accomodate the new IPv6 header.
    589 	 */
    590 	plen = m->m_pkthdr.len;
    591 	if (M_LEADINGSPACE(m->m_next) < sizeof(struct ip6_hdr)) {
    592 		struct mbuf *n;
    593 		MGET(n, M_DONTWAIT, MT_DATA);
    594 		if (!n) {
    595 			m_freem(m);
    596 			return ENOBUFS;
    597 		}
    598 		n->m_len = sizeof(struct ip6_hdr);
    599 		n->m_next = m->m_next;
    600 		m->m_next = n;
    601 		m->m_pkthdr.len += sizeof(struct ip6_hdr);
    602 		oip6 = mtod(n, struct ip6_hdr *);
    603 	} else {
    604 		m->m_next->m_len += sizeof(struct ip6_hdr);
    605 		m->m_next->m_data -= sizeof(struct ip6_hdr);
    606 		m->m_pkthdr.len += sizeof(struct ip6_hdr);
    607 		oip6 = mtod(m->m_next, struct ip6_hdr *);
    608 	}
    609 	ip6 = mtod(m, struct ip6_hdr *);
    610 	ovbcopy((caddr_t)ip6, (caddr_t)oip6, sizeof(struct ip6_hdr));
    611 
    612 	/* Fake link-local scope-class addresses */
    613 	if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_src))
    614 		oip6->ip6_src.s6_addr16[1] = 0;
    615 	if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_dst))
    616 		oip6->ip6_dst.s6_addr16[1] = 0;
    617 
    618 	/* construct new IPv6 header. see RFC 2401 5.1.2.2 */
    619 	/* ECN consideration. */
    620 	ip6_ecn_ingress(ip6_ipsec_ecn, &ip6->ip6_flow, &oip6->ip6_flow);
    621 	if (plen < IPV6_MAXPACKET - sizeof(struct ip6_hdr))
    622 		ip6->ip6_plen = htons(plen);
    623 	else {
    624 		/* ip6->ip6_plen will be updated in ip6_output() */
    625 	}
    626 	ip6->ip6_nxt = IPPROTO_IPV6;
    627 	sav->sah->saidx.src.sin6.sin6_addr = ip6->ip6_src;
    628 	sav->sah->saidx.dst.sin6.sin6_addr = ip6->ip6_dst;
    629 	ip6->ip6_hlim = IPV6_DEFHLIM;
    630 
    631 	/* XXX Should ip6_src be updated later ? */
    632 
    633 	return 0;
    634 }
    635 
    636 /*
    637  * IPsec output logic for IPv6, tunnel mode.
    638  */
    639 int
    640 ipsec6_output_tunnel(struct ipsec_output_state *state, struct secpolicy *sp, int flags)
    641 {
    642 	struct ip6_hdr *ip6;
    643 	struct ipsecrequest *isr;
    644 	struct secasindex saidx;
    645 	int error;
    646 	struct sockaddr_in6* dst6;
    647 	struct mbuf *m;
    648 
    649 	IPSEC_ASSERT(state != NULL, ("ipsec6_output: null state"));
    650 	IPSEC_ASSERT(state->m != NULL, ("ipsec6_output: null m"));
    651 	IPSEC_ASSERT(sp != NULL, ("ipsec6_output: null sp"));
    652 
    653 	KEYDEBUG(KEYDEBUG_IPSEC_DATA,
    654 		printf("ipsec6_output_tunnel: applyed SP\n");
    655 		kdebug_secpolicy(sp));
    656 
    657 	m = state->m;
    658 	/*
    659 	 * transport mode ipsec (before the 1st tunnel mode) is already
    660 	 * processed by ipsec6_output_trans().
    661 	 */
    662 	for (isr = sp->req; isr; isr = isr->next) {
    663 		if (isr->saidx.mode == IPSEC_MODE_TUNNEL)
    664 			break;
    665 	}
    666 	isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error);
    667 	if (isr == NULL)
    668 		goto bad;
    669 
    670 	/*
    671 	 * There may be the case that SA status will be changed when
    672 	 * we are refering to one. So calling splsoftnet().
    673 	 */
    674 	if (isr->saidx.mode == IPSEC_MODE_TUNNEL) {
    675 		/*
    676 		 * build IPsec tunnel.
    677 		 */
    678 		/* XXX should be processed with other familiy */
    679 		if (isr->sav->sah->saidx.src.sa.sa_family != AF_INET6) {
    680 			ipseclog((LOG_ERR, "ipsec6_output_tunnel: "
    681 			    "family mismatched between inner and outer, spi=%lu\n",
    682 			    ntohl(isr->sav->spi)));
    683 			newipsecstat.ips_out_inval++;
    684 			error = EAFNOSUPPORT;
    685 			goto bad;
    686 		}
    687 
    688 		m = ipsec6_splithdr(m);
    689 		if (!m) {
    690 			newipsecstat.ips_out_nomem++;
    691 			error = ENOMEM;
    692 			goto bad;
    693 		}
    694 		error = ipsec6_encapsulate(m, isr->sav);
    695 		if (error) {
    696 			m = NULL;
    697 			goto bad;
    698 		}
    699 		ip6 = mtod(m, struct ip6_hdr *);
    700 
    701 		state->ro = &isr->sav->sah->sa_route;
    702 		state->dst = (struct sockaddr *)&state->ro->ro_dst;
    703 		dst6 = (struct sockaddr_in6 *)state->dst;
    704 		if (state->ro->ro_rt
    705 		 && ((state->ro->ro_rt->rt_flags & RTF_UP) == 0
    706 		  || !IN6_ARE_ADDR_EQUAL(&dst6->sin6_addr, &ip6->ip6_dst))) {
    707 			RTFREE(state->ro->ro_rt);
    708 			state->ro->ro_rt = NULL;
    709 		}
    710 		if (state->ro->ro_rt == 0) {
    711 			bzero(dst6, sizeof(*dst6));
    712 			dst6->sin6_family = AF_INET6;
    713 			dst6->sin6_len = sizeof(*dst6);
    714 			dst6->sin6_addr = ip6->ip6_dst;
    715 			rtalloc(state->ro);
    716 		}
    717 		if (state->ro->ro_rt == 0) {
    718 			ip6stat.ip6s_noroute++;
    719 			newipsecstat.ips_out_noroute++;
    720 			error = EHOSTUNREACH;
    721 			goto bad;
    722 		}
    723 
    724 		/* adjust state->dst if tunnel endpoint is offlink */
    725 		if (state->ro->ro_rt->rt_flags & RTF_GATEWAY) {
    726 			state->dst = (struct sockaddr *)state->ro->ro_rt->rt_gateway;
    727 			dst6 = (struct sockaddr_in6 *)state->dst;
    728 		}
    729 	}
    730 
    731 	m = ipsec6_splithdr(m);
    732 	if (!m) {
    733 		newipsecstat.ips_out_nomem++;
    734 		error = ENOMEM;
    735 		goto bad;
    736 	}
    737 	ip6 = mtod(m, struct ip6_hdr *);
    738 	return (*isr->sav->tdb_xform->xf_output)(m, isr, NULL,
    739 		sizeof (struct ip6_hdr),
    740 		offsetof(struct ip6_hdr, ip6_nxt));
    741 bad:
    742 	if (m)
    743 		m_freem(m);
    744 	state->m = NULL;
    745 	return error;
    746 }
    747 #endif /*INET6*/
    748