/* $NetBSD: ipsec_output.c,v 1.87 2024/07/05 04:31:54 rin Exp $ */

/* $NetBSD: ipsec_output.c,v 1.87 2024/07/05 04:31:54 rin Exp $ */

/*
* Copyright (c) 2002, 2003 Sam Leffler, Errno Consulting
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD: sys/netipsec/ipsec_output.c,v 1.3.2.2 2003/03/28 20:32:53 sam Exp $
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ipsec_output.c,v 1.87 2024/07/05 04:31:54 rin Exp $");

#if defined(_KERNEL_OPT)
#include "opt_inet.h"
#include "opt_net_mpsafe.h"
#endif

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/errno.h>
#include <sys/syslog.h>

#include <net/if.h>
#include <net/route.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/in_var.h>
#include <netinet/ip_ecn.h>

#include <netinet/ip6.h>
#ifdef INET6
#include <netinet6/ip6_var.h>
#endif
#include <netinet/in_pcb.h>
#ifdef INET6
#include <netinet/icmp6.h>
#endif
#include <netinet/udp.h>

#include <netipsec/ipsec.h>
#include <netipsec/ipsec_var.h>
#include <netipsec/ipsec_private.h>
#ifdef INET6
#include <netipsec/ipsec6.h>
#endif
#include <netipsec/ah_var.h>
#include <netipsec/esp_var.h>
#include <netipsec/ipcomp_var.h>

#include <netipsec/xform.h>

#include <netipsec/key.h>
#include <netipsec/keydb.h>
#include <netipsec/key_debug.h>

static percpu_t *ipsec_rtcache_percpu __cacheline_aligned;

/*
* Add a IPSEC_OUT_DONE tag to mark that we have finished the ipsec processing
* It will be used by ip{,6}_output to check if we have already or not
* processed this packet.
*/
static int
ipsec_register_done(struct mbuf *m, int *error)
{
struct m_tag *mtag;

mtag = m_tag_get(PACKET_TAG_IPSEC_OUT_DONE, 0, M_NOWAIT);
if (mtag == NULL) {
IPSECLOG(LOG_DEBUG, "could not get packet tag\n");
*error = ENOMEM;
return -1;
}

m_tag_prepend(m, mtag);
return 0;
}

static int
ipsec_reinject_ipstack(struct mbuf *m, int af, int flags)
{
int rv = -1;
struct route *ro;

KASSERT(af == AF_INET || af == AF_INET6);

KERNEL_LOCK_UNLESS_NET_MPSAFE();
ro = rtcache_percpu_getref(ipsec_rtcache_percpu);
switch (af) {
#ifdef INET
case AF_INET:
rv = ip_output(m, NULL, ro, IP_RAWOUTPUT|IP_NOIPNEWID,
NULL, NULL);
break;
#endif
#ifdef INET6
case AF_INET6:
/*
* We don't need massage, IPv6 header fields are always in
* net endian.
*/
rv = ip6_output(m, NULL, ro, flags, NULL, NULL, NULL);
break;
#endif
}
rtcache_percpu_putref(ipsec_rtcache_percpu);
KERNEL_UNLOCK_UNLESS_NET_MPSAFE();

return rv;
}

int
ipsec_process_done(struct mbuf *m, const struct ipsecrequest *isr,
struct secasvar *sav, int flags)
{
struct secasindex *saidx;
int error;
#ifdef INET
struct ip *ip;
#endif
#ifdef INET6
struct ip6_hdr *ip6;
#endif
struct mbuf *mo;
struct udphdr *udp = NULL;
int hlen, roff, iphlen;

KASSERT(m != NULL);
KASSERT(isr != NULL);
KASSERT(sav != NULL);

saidx = &sav->sah->saidx;

if (sav->natt_type != 0) {
hlen = sizeof(struct udphdr);

switch (saidx->dst.sa.sa_family) {
#ifdef INET
case AF_INET:
ip = mtod(m, struct ip *);
mo = m_makespace(m, sizeof(struct ip), hlen, &roff);
iphlen = ip->ip_hl << 2;
break;
#endif
#ifdef INET6
case AF_INET6:
ip6 = mtod(m, struct ip6_hdr *);
mo = m_makespace(m, sizeof(struct ip6_hdr), hlen, &roff);
iphlen = sizeof(*ip6);
break;
#endif
default:
IPSECLOG(LOG_DEBUG, "unknown protocol family %u\n",
saidx->dst.sa.sa_family);
error = ENXIO;
goto bad;
}

if (mo == NULL) {
char buf[IPSEC_ADDRSTRLEN];
IPSECLOG(LOG_DEBUG,
"failed to inject %u byte UDP for SA %s/%08lx\n",
hlen, ipsec_address(&saidx->dst, buf, sizeof(buf)),
(u_long)ntohl(sav->spi));
error = ENOBUFS;
goto bad;
}

udp = (struct udphdr *)(mtod(mo, char *) + roff);
udp->uh_sport = key_portfromsaddr(&saidx->src);
udp->uh_dport = key_portfromsaddr(&saidx->dst);
udp->uh_sum = 0;
udp->uh_ulen = htons(m->m_pkthdr.len - iphlen);
}

/*
* Fix the header length, for AH processing.
*/
switch (saidx->dst.sa.sa_family) {
#ifdef INET
case AF_INET:
ip = mtod(m, struct ip *);
ip->ip_len = htons(m->m_pkthdr.len);
/* IPv4 packet does not have to be set UDP checksum. */
if (sav->natt_type != 0)
ip->ip_p = IPPROTO_UDP;
break;
#endif
#ifdef INET6
case AF_INET6:
if (m->m_pkthdr.len < sizeof(struct ip6_hdr)) {
error = ENXIO;
goto bad;
}
if (m->m_pkthdr.len - sizeof(struct ip6_hdr) > IPV6_MAXPACKET) {
/* No jumbogram support. */
error = ENXIO; /*?*/
goto bad;
}
ip6 = mtod(m, struct ip6_hdr *);
ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
/* IPv6 packet should be set UDP checksum. */
if (sav->natt_type != 0) {
ip6->ip6_nxt = IPPROTO_UDP;
ipsec6_udp_cksum(m);
}
break;
#endif
default:
IPSECLOG(LOG_DEBUG, "unknown protocol family %u\n",
saidx->dst.sa.sa_family);
error = ENXIO;
goto bad;
}

key_sa_recordxfer(sav, m);

/*
* If there's another (bundled) SA to apply, do so.
* Note that this puts a burden on the kernel stack size.
* If this is a problem we'll need to introduce a queue
* to set the packet on so we can unwind the stack before
* doing further processing.
*/
if (isr->next) {
IPSEC_STATINC(IPSEC_STAT_OUT_BUNDLESA);
switch (saidx->dst.sa.sa_family) {
#ifdef INET
case AF_INET:
return ipsec4_process_packet(m, isr->next, NULL);
#endif
#ifdef INET6
case AF_INET6:
return ipsec6_process_packet(m, isr->next, flags);
#endif
default:
IPSECLOG(LOG_DEBUG, "unknown protocol family %u\n",
saidx->dst.sa.sa_family);
error = ENXIO;
goto bad;
}
}

/*
* We're done with IPsec processing, mark the packet as processed,
* and transmit it using the appropriate network protocol
* (IPv4/IPv6).
*/

if (ipsec_register_done(m, &error) < 0)
goto bad;

return ipsec_reinject_ipstack(m, saidx->dst.sa.sa_family, flags);

bad:
m_freem(m);
return error;
}

static void
ipsec_fill_saidx_bymbuf(struct secasindex *saidx, const struct mbuf *m,
const int af)
{
struct m_tag *mtag;
u_int16_t natt_src = IPSEC_PORT_ANY;
u_int16_t natt_dst = IPSEC_PORT_ANY;

/*
* For NAT-T enabled ipsecif(4), set NAT-T port numbers
* even if the saidx uses transport mode.
*
* See also ipsecif[46]_output().
*/
mtag = m_tag_find(m, PACKET_TAG_IPSEC_NAT_T_PORTS);
if (mtag) {
u_int16_t *natt_ports;

natt_ports = (u_int16_t *)(mtag + 1);
natt_src = natt_ports[1];
natt_dst = natt_ports[0];
}

if (af == AF_INET) {
struct sockaddr_in *sin;
struct ip *ip = mtod(m, struct ip *);

if (saidx->src.sa.sa_len == 0) {
sin = &saidx->src.sin;
sin->sin_len = sizeof(*sin);
sin->sin_family = AF_INET;
sin->sin_port = natt_src;
sin->sin_addr = ip->ip_src;
}
if (saidx->dst.sa.sa_len == 0) {
sin = &saidx->dst.sin;
sin->sin_len = sizeof(*sin);
sin->sin_family = AF_INET;
sin->sin_port = natt_dst;
sin->sin_addr = ip->ip_dst;
}
} else {
struct sockaddr_in6 *sin6;
struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);

if (saidx->src.sin6.sin6_len == 0) {
sin6 = (struct sockaddr_in6 *)&saidx->src;
sin6->sin6_len = sizeof(*sin6);
sin6->sin6_family = AF_INET6;
sin6->sin6_port = natt_src;
sin6->sin6_addr = ip6->ip6_src;
if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) {
/* fix scope id for comparing SPD */
sin6->sin6_addr.s6_addr16[1] = 0;
sin6->sin6_scope_id =
ntohs(ip6->ip6_src.s6_addr16[1]);
}
}
if (saidx->dst.sin6.sin6_len == 0) {
sin6 = (struct sockaddr_in6 *)&saidx->dst;
sin6->sin6_len = sizeof(*sin6);
sin6->sin6_family = AF_INET6;
sin6->sin6_port = natt_dst;
sin6->sin6_addr = ip6->ip6_dst;
if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) {
/* fix scope id for comparing SPD */
sin6->sin6_addr.s6_addr16[1] = 0;
sin6->sin6_scope_id =
ntohs(ip6->ip6_dst.s6_addr16[1]);
}
}
}
}

struct secasvar *
ipsec_lookup_sa(const struct ipsecrequest *isr, const struct mbuf *m)
{
struct secasindex saidx;

saidx = isr->saidx;
if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) {
/* Fillin unspecified SA peers only for transport mode */
ipsec_fill_saidx_bymbuf(&saidx, m, isr->saidx.dst.sa.sa_family);
}

return key_lookup_sa_bysaidx(&saidx);
}

/*
* ipsec_nextisr can return :
* - isr == NULL and error != 0 => something is bad : the packet must be
* discarded
* - isr == NULL and error == 0 => no more rules to apply, ipsec processing
* is done, reinject it in ip stack
* - isr != NULL (error == 0) => we need to apply one rule to the packet
*/
static const struct ipsecrequest *
ipsec_nextisr(struct mbuf *m, const struct ipsecrequest *isr, int af,
int *error, struct secasvar **ret)
{
#define IPSEC_OSTAT(type) \
do { \
switch (isr->saidx.proto) { \
case IPPROTO_ESP: \
ESP_STATINC(ESP_STAT_ ## type); \
break; \
case IPPROTO_AH: \
AH_STATINC(AH_STAT_ ## type); \
break; \
default: \
IPCOMP_STATINC(IPCOMP_STAT_ ## type); \
break; \
} \
} while (/*CONSTCOND*/0)

struct secasvar *sav = NULL;
struct secasindex saidx;

KASSERTMSG(af == AF_INET || af == AF_INET6,
"invalid address family %u", af);
again:
/*
* Craft SA index to search for proper SA. Note that
* we only fillin unspecified SA peers for transport
* mode; for tunnel mode they must already be filled in.
*/
saidx = isr->saidx;
if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) {
/* Fillin unspecified SA peers only for transport mode */
ipsec_fill_saidx_bymbuf(&saidx, m, af);
}

/*
* Lookup SA and validate it.
*/
*error = key_checkrequest(isr, &saidx, &sav);
if (*error != 0) {
/*
* IPsec processing is required, but no SA found.
* I assume that key_acquire() had been called
* to get/establish the SA. Here I discard
* this packet because it is responsibility for
* upper layer to retransmit the packet.
*/
IPSEC_STATINC(IPSEC_STAT_OUT_NOSA);
goto bad;
}
/* sav may be NULL here if we have an USE rule */
if (sav == NULL) {
KASSERTMSG(ipsec_get_reqlevel(isr) == IPSEC_LEVEL_USE,
"no SA found, but required; level %u",
ipsec_get_reqlevel(isr));
isr = isr->next;
/*
* No more rules to apply, return NULL isr and no error.
* It can happen when the last rules are USE rules.
*/
if (isr == NULL) {
*ret = NULL;
*error = 0;
return isr;
}
goto again;
}

/*
* Check system global policy controls.
*/
if ((isr->saidx.proto == IPPROTO_ESP && !esp_enable) ||
(isr->saidx.proto == IPPROTO_AH && !ah_enable) ||
(isr->saidx.proto == IPPROTO_IPCOMP && !ipcomp_enable)) {
IPSECLOG(LOG_DEBUG, "IPsec outbound packet dropped due"
" to policy (check your sysctls)\n");
IPSEC_OSTAT(PDROPS);
*error = EHOSTUNREACH;
KEY_SA_UNREF(&sav);
goto bad;
}

/*
* Sanity check the SA contents for the caller
* before they invoke the xform output method.
*/
KASSERT(sav->tdb_xform != NULL);
*ret = sav;
return isr;

bad:
KASSERTMSG(*error != 0, "error return w/ no error code");
return NULL;
#undef IPSEC_OSTAT
}

#ifdef INET
/*
* IPsec output logic for IPv4.
*/
int
ipsec4_process_packet(struct mbuf *m, const struct ipsecrequest *isr,
u_long *mtu)
{
struct secasvar *sav = NULL;
struct ip *ip;
int error, i, off;
union sockaddr_union *dst;
int setdf;

KASSERT(m != NULL);
KASSERT(m->m_nextpkt == NULL);
KASSERT(isr != NULL);

isr = ipsec_nextisr(m, isr, AF_INET, &error, &sav);
if (isr == NULL) {
if (error != 0) {
goto bad;
} else {
if (ipsec_register_done(m, &error) < 0)
goto bad;

return ipsec_reinject_ipstack(m, AF_INET, 0);
}
}
KASSERT(sav != NULL);

if (m->m_len < sizeof(struct ip) &&
(m = m_pullup(m, sizeof(struct ip))) == NULL) {
error = ENOBUFS;
goto unrefsav;
}

/*
* Check if we need to handle NAT-T fragmentation.
*/
if (isr == isr->sp->req) { /* Check only if called from ipsec4_output */
KASSERT(mtu != NULL);
ip = mtod(m, struct ip *);
if (!(sav->natt_type & UDP_ENCAP_ESPINUDP)) {
goto noneed;
}
if (ntohs(ip->ip_len) <= sav->esp_frag)
goto noneed;
*mtu = sav->esp_frag;
KEY_SA_UNREF(&sav);
return 0;
}
noneed:
dst = &sav->sah->saidx.dst;

/*
* Collect IP_DF state from the outer header.
*/
if (dst->sa.sa_family == AF_INET) {
ip = mtod(m, struct ip *);
/* Honor system-wide control of how to handle IP_DF */
switch (ip4_ipsec_dfbit) {
case 0: /* clear in outer header */
case 1: /* set in outer header */
setdf = ip4_ipsec_dfbit;
break;
default: /* propagate to outer header */
setdf = ip->ip_off;
setdf = ntohs(setdf);
setdf = htons(setdf & IP_DF);
break;
}
} else {
ip = NULL; /* keep compiler happy */
setdf = 0;
}

/* Do the appropriate encapsulation, if necessary */
if (isr->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
dst->sa.sa_family != AF_INET || /* PF mismatch */
(dst->sa.sa_family == AF_INET && /* Proxy */
dst->sin.sin_addr.s_addr != INADDR_ANY &&
dst->sin.sin_addr.s_addr != ip->ip_dst.s_addr)) {
struct mbuf *mp;

/* Fix IPv4 header checksum and length */
ip = mtod(m, struct ip *);
ip->ip_len = htons(m->m_pkthdr.len);
ip->ip_sum = 0;
ip->ip_sum = in_cksum(m, ip->ip_hl << 2);

/* Encapsulate the packet */
error = ipip_output(m, sav, &mp);
if (mp == NULL && !error) {
/* Should never happen. */
IPSECLOG(LOG_DEBUG,
"ipip_output returns no mbuf and no error!");
error = EFAULT;
}
if (error) {
if (mp) {
/* XXX: Should never happen! */
m_freem(mp);
}
m = NULL; /* ipip_output() already freed it */
goto unrefsav;
}
m = mp, mp = NULL;

/*
* ipip_output clears IP_DF in the new header. If
* we need to propagate IP_DF from the outer header,
* then we have to do it here.
*
* XXX shouldn't assume what ipip_output does.
*/
if (dst->sa.sa_family == AF_INET && setdf) {
if (m->m_len < sizeof(struct ip) &&
(m = m_pullup(m, sizeof(struct ip))) == NULL) {
error = ENOBUFS;
goto unrefsav;
}
ip = mtod(m, struct ip *);
ip->ip_off |= htons(IP_DF);
}
}

/*
* Dispatch to the appropriate IPsec transform logic. The
* packet will be returned for transmission after crypto
* processing, etc. are completed. For encapsulation we
* bypass this call because of the explicit call done above
* (necessary to deal with IP_DF handling for IPv4).
*
* NB: m & sav are ``passed to caller'' who's responsible for
* for reclaiming their resources.
*/
if (sav->tdb_xform->xf_type != XF_IP4) {
if (dst->sa.sa_family == AF_INET) {
ip = mtod(m, struct ip *);
i = ip->ip_hl << 2;
off = offsetof(struct ip, ip_p);
} else {
i = sizeof(struct ip6_hdr);
off = offsetof(struct ip6_hdr, ip6_nxt);
}
error = (*sav->tdb_xform->xf_output)(m, isr, sav, i, off, 0);
} else {
error = ipsec_process_done(m, isr, sav, 0);
}
KEY_SA_UNREF(&sav);
return error;

unrefsav:
KEY_SA_UNREF(&sav);
bad:
m_freem(m);
return error;
}
#endif

#ifdef INET6
static int
compute_ipsec_pos(struct mbuf *m, int *i, int *off)
{
struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
struct ip6_ext ip6e;
int dstopt = 0;
int nxt;

*i = sizeof(struct ip6_hdr);
*off = offsetof(struct ip6_hdr, ip6_nxt);
nxt = ip6->ip6_nxt;

/*
* chase mbuf chain to find the appropriate place to
* put AH/ESP/IPcomp header.
* IPv6 hbh dest1 rthdr ah* [esp* dest2 payload]
*/
while (1) {
switch (nxt) {
case IPPROTO_AH:
case IPPROTO_ESP:
case IPPROTO_IPCOMP:
/*
* We should not skip security header added
* beforehand.
*/
return 0;

case IPPROTO_HOPOPTS:
case IPPROTO_DSTOPTS:
case IPPROTO_ROUTING:
if (*i + sizeof(ip6e) > m->m_pkthdr.len) {
return EINVAL;
}

/*
* If we see 2nd destination option header,
* we should stop there.
*/
if (nxt == IPPROTO_DSTOPTS && dstopt)
return 0;

if (nxt == IPPROTO_DSTOPTS) {
/*
* Seen 1st or 2nd destination option.
* next time we see one, it must be 2nd.
*/
dstopt = 1;
} else if (nxt == IPPROTO_ROUTING) {
/*
* If we see destination option next
* time, it must be dest2.
*/
dstopt = 2;
}

/* skip this header */
m_copydata(m, *i, sizeof(ip6e), &ip6e);
nxt = ip6e.ip6e_nxt;
*off = *i + offsetof(struct ip6_ext, ip6e_nxt);
*i += (ip6e.ip6e_len + 1) << 3;
if (*i > m->m_pkthdr.len) {
return EINVAL;
}
break;
default:
return 0;
}
}

return 0;
}

static int
in6_sa_equal_addrwithscope(const struct sockaddr_in6 *sa,
const struct in6_addr *ia)
{
struct in6_addr ia2;

memcpy(&ia2, &sa->sin6_addr, sizeof(ia2));
if (IN6_IS_SCOPE_LINKLOCAL(&sa->sin6_addr))
ia2.s6_addr16[1] = htons(sa->sin6_scope_id);

return IN6_ARE_ADDR_EQUAL(ia, &ia2);
}

int
ipsec6_process_packet(struct mbuf *m, const struct ipsecrequest *isr, int flags)
{
struct secasvar *sav = NULL;
struct ip6_hdr *ip6;
int error, i, off;
union sockaddr_union *dst;

KASSERT(m != NULL);
KASSERT(m->m_nextpkt == NULL);
KASSERT(isr != NULL);

isr = ipsec_nextisr(m, isr, AF_INET6, &error, &sav);
if (isr == NULL) {
if (error != 0) {
/* XXX Should we send a notification ? */
goto bad;
} else {
if (ipsec_register_done(m, &error) < 0)
goto bad;

return ipsec_reinject_ipstack(m, AF_INET6, flags);
}
}

KASSERT(sav != NULL);
dst = &sav->sah->saidx.dst;

if (m->m_len < sizeof(struct ip6_hdr)) {
if ((m = m_pullup(m,sizeof(struct ip6_hdr))) == NULL) {
error = ENOBUFS;
goto unrefsav;
}
}
ip6 = mtod(m, struct ip6_hdr *);

/* Do the appropriate encapsulation, if necessary */
if (isr->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
dst->sa.sa_family != AF_INET6 || /* AF mismatch */
((dst->sa.sa_family == AF_INET6) &&
(!IN6_IS_ADDR_UNSPECIFIED(&dst->sin6.sin6_addr)) &&
(!in6_sa_equal_addrwithscope(&dst->sin6, &ip6->ip6_dst)))) {
struct mbuf *mp;

if (m->m_pkthdr.len - sizeof(*ip6) > IPV6_MAXPACKET) {
/* No jumbogram support. */
error = ENXIO; /*XXX*/
goto unrefsav;
}

/* Fix IPv6 header payload length. */
ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6));

/* Encapsulate the packet */
error = ipip_output(m, sav, &mp);
if (mp == NULL && !error) {
/* Should never happen. */
IPSECLOG(LOG_DEBUG,
"ipip_output returns no mbuf and no error!");
error = EFAULT;
}

if (error) {
if (mp) {
/* XXX: Should never happen! */
m_freem(mp);
}
m = NULL; /* ipip_output() already freed it */
goto unrefsav;
}

m = mp;
mp = NULL;
}

if (dst->sa.sa_family == AF_INET) {
struct ip *ip;
ip = mtod(m, struct ip *);
i = ip->ip_hl << 2;
off = offsetof(struct ip, ip_p);
} else {
error = compute_ipsec_pos(m, &i, &off);
if (error)
goto unrefsav;
}
error = (*sav->tdb_xform->xf_output)(m, isr, sav, i, off, flags);
KEY_SA_UNREF(&sav);
return error;

unrefsav:
KEY_SA_UNREF(&sav);
bad:
m_freem(m);
return error;
}
#endif /* INET6 */

void
ipsec_output_init(void)
{

ipsec_rtcache_percpu = rtcache_percpu_alloc();
}