path: root/sys/netinet/ip_ipsp.c

/*	$OpenBSD: ip_ipsp.c,v 1.93 2000/06/18 19:05:46 angelos Exp $	*/

/*
 * The authors of this code are John Ioannidis (ji@tla.org),
 * Angelos D. Keromytis (kermit@csd.uch.gr), 
 * Niels Provos (provos@physnet.uni-hamburg.de) and
 * Niklas Hallqvist (niklas@appli.se).
 *
 * This code was written by John Ioannidis for BSD/OS in Athens, Greece, 
 * in November 1995.
 *
 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
 * by Angelos D. Keromytis.
 *
 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
 * and Niels Provos.
 *
 * Additional features in 1999 by Angelos D. Keromytis and Niklas Hallqvist.
 *
 * Copyright (c) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
 * Angelos D. Keromytis and Niels Provos.
 * Copyright (c) 1999 Niklas Hallqvist.
 *
 * Permission to use, copy, and modify this software without fee
 * is hereby granted, provided that this entire notice is included in
 * all copies of any software which is or includes a copy or
 * modification of this software. 
 * You may use this code under the GNU public license if you so wish. Please
 * contribute changes back to the authors under this freer than GPL license
 * so that we may further the use of strong encryption without limitations to
 * all.
 *
 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
 * PURPOSE.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/errno.h>
#include <sys/kernel.h>
#include <sys/proc.h>

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

#ifdef INET
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/ip_var.h>
#endif /* INET */

#ifdef INET6
#ifndef INET
#include <netinet/in.h>
#endif
#endif /* INET6 */

#include <net/pfkeyv2.h>

#include <netinet/ip_ipsp.h>
#include <netinet/ip_ah.h>
#include <netinet/ip_esp.h>

#include <crypto/crypto.h>
#include <crypto/xform.h>

#include <dev/rndvar.h>

#ifdef DDB
#include <ddb/db_output.h>
void tdb_hashstats(void);
#endif

#ifdef ENCDEBUG
#define DPRINTF(x)	if (encdebug) printf x
#else
#define DPRINTF(x)
#endif

#ifndef offsetof
#define offsetof(s, e) ((int)&((s *)0)->e)
#endif

#ifdef __GNUC__
#define INLINE static __inline
#endif

int		ipsp_kern __P((int, char **, int));
u_int8_t       	get_sa_require  __P((struct inpcb *));
int		check_ipsec_policy  __P((struct inpcb *, void *));
void		tdb_rehash __P((void));

extern int	ipsec_auth_default_level;
extern int	ipsec_esp_trans_default_level;
extern int	ipsec_esp_network_default_level;

extern int encdebug;
int ipsec_in_use = 0;
u_int32_t kernfs_epoch = 0;

struct expclusterlist_head expclusterlist =
    TAILQ_HEAD_INITIALIZER(expclusterlist);
struct explist_head explist = TAILQ_HEAD_INITIALIZER(explist);

/*
 * This is the proper place to define the various encapsulation transforms.
 */

struct xformsw xformsw[] = {
    { XF_IP4,	         0,               "IPv4 Simple Encapsulation",
      ipe4_attach,       ipe4_init,       ipe4_zeroize,
      (int (*)(struct mbuf *, struct tdb *, int, int))ipe4_input, 
      ipip_output, },
    { XF_AH,	 XFT_AUTH,	    "IPsec AH",
      ah_attach,	ah_init,   ah_zeroize,
      ah_input,	 	ah_output, },
    { XF_ESP,	 XFT_CONF|XFT_AUTH, "IPsec ESP",
      esp_attach,	esp_init,  esp_zeroize,
      esp_input,	esp_output, },
#ifdef TCP_SIGNATURE
    { XF_TCPSIGNATURE,	 XFT_AUTH, "TCP MD5 Signature Option, RFC 2385",
      tcp_signature_tdb_attach, 	tcp_signature_tdb_init,
      tcp_signature_tdb_zeroize,	tcp_signature_tdb_input,
      tcp_signature_tdb_output, }
#endif /* TCP_SIGNATURE */
};

struct xformsw *xformswNXFORMSW = &xformsw[sizeof(xformsw)/sizeof(xformsw[0])];

unsigned char ipseczeroes[IPSEC_ZEROES_SIZE]; /* zeroes! */ 

#define TDB_HASHSIZE_INIT 32
static struct tdb **tdbh = NULL, *tdb_bypass = NULL;
static u_int tdb_hashmask = TDB_HASHSIZE_INIT - 1;
static int tdb_count;

/*
 * Check which transformations are required.
 */
u_int8_t
get_sa_require(struct inpcb *inp)
{
    u_int8_t sareq = 0;
       
    if (inp != NULL)
    {
	sareq |= inp->inp_seclevel[SL_AUTH] >= IPSEC_LEVEL_USE ? 
		 NOTIFY_SATYPE_AUTH : 0;
	sareq |= inp->inp_seclevel[SL_ESP_TRANS] >= IPSEC_LEVEL_USE ?
		 NOTIFY_SATYPE_CONF : 0;
	sareq |= inp->inp_seclevel[SL_ESP_NETWORK] >= IPSEC_LEVEL_USE ?
		 NOTIFY_SATYPE_TUNNEL : 0;
    }
    else
    {
	sareq |= ipsec_auth_default_level >= IPSEC_LEVEL_USE ? 
		 NOTIFY_SATYPE_AUTH : 0;
	sareq |= ipsec_esp_trans_default_level >= IPSEC_LEVEL_USE ? 
		 NOTIFY_SATYPE_CONF : 0;
	sareq |= ipsec_esp_network_default_level >= IPSEC_LEVEL_USE ? 
		 NOTIFY_SATYPE_TUNNEL : 0;
    }
    
    return (sareq);
}

/*
 * Check the socket policy and request a new SA with a key management
 * daemon. Sometimes inp does not contain the destination address;
 * in that case use dst.
 */
int
check_ipsec_policy(struct inpcb *inp, void *daddr)
{
    struct route_enc re0, *re = &re0;
    struct sockaddr_encap *dst, *gw;
    u_int8_t sa_require, sa_have;
    struct tdb tdb2, *tdb = NULL;
    union sockaddr_union sunion;
    struct socket *so;
    int error, i, s;

    if (inp == NULL || ((so = inp->inp_socket) == 0))
      return (EINVAL);

    /* If IPsec is not required just use what we got */
    if (!(sa_require = inp->inp_secrequire))
      return 0;

    s = spltdb();
    if (!inp->inp_tdb)
    {
	bzero((caddr_t) re, sizeof(*re));
	dst = (struct sockaddr_encap *) &re->re_dst;
	dst->sen_family = PF_KEY;

#ifdef INET6
	if (inp->inp_flags & INP_IPV6)
	{
	    dst->sen_len = SENT_IP6_LEN;
	    dst->sen_type = SENT_IP6;
	    dst->sen_ip6_src = inp->inp_laddr6;
	    if (inp->inp_faddr6.s6_addr)
	      dst->sen_ip6_dst = inp->inp_faddr6;
	    else
	      dst->sen_ip6_dst =  (*((struct in6_addr *) daddr));

	    dst->sen_ip6_proto = so->so_proto->pr_protocol;

	    switch (dst->sen_ip6_proto)
	    {
		case IPPROTO_UDP:
		case IPPROTO_TCP:
		    dst->sen_ip6_sport = htons(inp->inp_lport);
		    dst->sen_ip6_dport = htons(inp->inp_fport);
		    break;

		default:
		    dst->sen_ip6_sport = 0;
		    dst->sen_ip6_dport = 0;
	    }
	}
#endif /* INET6 */

#ifdef INET
	if (!(inp->inp_flags & INP_IPV6))
	{
	    dst->sen_len = SENT_IP4_LEN;
	    dst->sen_type = SENT_IP4;
	    dst->sen_ip_src = inp->inp_laddr;

	    if (inp->inp_faddr.s_addr)
	      dst->sen_ip_dst = inp->inp_faddr;
	    else
	      dst->sen_ip_dst = (*((struct in_addr *) daddr));

	    dst->sen_proto = so->so_proto->pr_protocol;

	    switch (dst->sen_proto)
	    {
		case IPPROTO_UDP:
		case IPPROTO_TCP:
		    dst->sen_sport = htons(inp->inp_lport);
		    dst->sen_dport = htons(inp->inp_fport);
		    break;

		default:
		    dst->sen_sport = 0;
		    dst->sen_dport = 0;
	    }
	}
#endif /* INET */

	/* Try to find a flow */
	rtalloc((struct route *) re);

	if (re->re_rt != NULL)
	{
	    gw = (struct sockaddr_encap *) (re->re_rt->rt_gateway);

#ifdef INET
	    if (gw->sen_type == SENT_IPSP)
	    {
		bzero(&sunion, sizeof(sunion));
	        sunion.sin.sin_family = AF_INET;
		sunion.sin.sin_len = sizeof(struct sockaddr_in);
		sunion.sin.sin_addr = gw->sen_ipsp_dst;
	      
		tdb = (struct tdb *) gettdb(gw->sen_ipsp_spi, &sunion,
					    gw->sen_ipsp_sproto);
	    }
#endif /* INET */

#ifdef INET6
	    if (gw->sen_type == SENT_IPSP6)
	    {
		bzero(&sunion, sizeof(sunion));
	        sunion.sin6.sin6_family = AF_INET6;
		sunion.sin6.sin6_len = sizeof(struct sockaddr_in6);
		sunion.sin6.sin6_addr = gw->sen_ipsp6_dst;
	      
		tdb = (struct tdb *) gettdb(gw->sen_ipsp6_spi, &sunion,
					    gw->sen_ipsp6_sproto);
	    }
#endif /* INET6 */

	    RTFREE(re->re_rt);
	}
    }
    else
      tdb = inp->inp_tdb;

    if (tdb)
      SPI_CHAIN_ATTRIB(sa_have, tdb_onext, tdb);
    else
      sa_have = 0;

    splx(s);

    /* Check if our requirements are met */
    if (!(sa_require & ~sa_have))
      return 0;

    error = i = 0;

    inp->inp_secresult = SR_WAIT;

    /* If necessary try to notify keymanagement three times */
    while (i < 3)
    {
	switch (dst->sen_type)
	{
#ifdef INET
	    case SENT_IP4:
		DPRINTF(("ipsec: send SA request (%d), remote IPv4 address: %s, SA type: %d\n", i + 1, inet_ntoa4(dst->sen_ip_dst), sa_require));
		break;
#endif /* INET */

#ifdef INET6
	    case SENT_IP6:
		DPRINTF(("ipsec: send SA request (%d), remote IPv6 address: %s, SA type: %d\n", i + 1, ip6_sprintf(dst->sen_ip6_dst), sa_require));
		break;
#endif /* INET6 */

	    default:
		DPRINTF(("ipsec: unsupported protocol family %d, cannot notify kkey management\n", dst->sen_type));
		return EPFNOSUPPORT;
	}

	/* Initialize TDB for PF_KEY notification */
	bzero(&tdb2, sizeof(tdb2));
	tdb2.tdb_satype = get_sa_require(inp);

#ifdef INET
	if (!(inp->inp_flags & INP_IPV6))
	{
	    tdb2.tdb_src.sin.sin_family = AF_INET;
	    tdb2.tdb_src.sin.sin_len = sizeof(struct sockaddr_in);
	    tdb2.tdb_src.sin.sin_addr = inp->inp_laddr;

	    tdb2.tdb_dst.sin.sin_family = AF_INET;
	    tdb2.tdb_dst.sin.sin_len = sizeof(struct sockaddr_in);
	    tdb2.tdb_dst.sin.sin_addr = inp->inp_faddr;
	}
#endif /* INET */

#ifdef INET6
	if (inp->inp_flags & INP_IPV6)
	{
	    tdb2.tdb_src.sin6.sin6_family = AF_INET6;
	    tdb2.tdb_src.sin6.sin6_len = sizeof(struct sockaddr_in6);
	    tdb2.tdb_src.sin6.sin6_addr = inp->inp_laddr6;

	    tdb2.tdb_dst.sin6.sin6_family = AF_INET6;
	    tdb2.tdb_dst.sin6.sin6_len = sizeof(struct sockaddr_in6);
	    tdb2.tdb_dst.sin6.sin6_addr = inp->inp_faddr6;
	}
#endif /* INET6 */

	error = ipsp_acquire_sa(&tdb2);
	if (error)
	  return error;

	/* 
	 * Wait for the keymanagement daemon to establich a new SA,
	 * even on error check again, perhaps some other process
	 * already established the necessary SA.
	 */
	error = tsleep((caddr_t)inp, PSOCK|PCATCH, "ipsecnotify", 30*hz);
	DPRINTF(("check_ipsec: sleep %d\n", error));

	if (error && error != EWOULDBLOCK)
	  break;

	/* 
	 * A Key Management daemon returned an apropriate SA back
	 * to the kernel, the kernel noted that state in the waiting
	 * socket.
	 */
	if (inp->inp_secresult == SR_SUCCESS)
	  return (0);

	/*
	 * Key Management returned a permanent failure, we do not
	 * need to retry again.
	 *
	 * XXX when more than one key management daemon is available
	 * XXX we can not do that.
	 */
	if (inp->inp_secresult == SR_FAILED)
	  break;

	i++;
    }

    return (error ? error : EWOULDBLOCK);
}

/*
 * Add an inpcb to the list of inpcb which reference this tdb directly.
 */
void
tdb_add_inp(struct tdb *tdb, struct inpcb *inp)
{
    int s = spltdb();

    if (inp->inp_tdb)
    {
	if (inp->inp_tdb == tdb)
	{
	    splx(s);
	    return;
	}

	TAILQ_REMOVE(&inp->inp_tdb->tdb_inp, inp, inp_tdb_next);
    }

    inp->inp_tdb = tdb;
    TAILQ_INSERT_TAIL(&tdb->tdb_inp, inp, inp_tdb_next);
    splx(s);

    DPRINTF(("tdb_add_inp: tdb: %p, inp: %p\n", tdb, inp));
}

/*
 * Reserve an SPI; the SA is not valid yet though.  We use SPI_LOCAL_USE as
 * an error return value.  It'll not be a problem that we also use that
 * for demand-keying as that is manually specified.
 */
u_int32_t
reserve_spi(u_int32_t sspi, u_int32_t tspi, union sockaddr_union *src,
	    union sockaddr_union *dst, u_int8_t sproto, int *errval)
{
    struct tdb *tdbp;
    u_int32_t spi;
    int nums, s;

    /* Don't accept ranges only encompassing reserved SPIs.  */
    if (tspi < sspi || tspi <= SPI_RESERVED_MAX)
    {
	(*errval) = EINVAL;
	return 0;
    }

    /* Limit the range to not include reserved areas.  */
    if (sspi <= SPI_RESERVED_MAX)
      sspi = SPI_RESERVED_MAX + 1;

    if (sspi == tspi)   /* Asking for a specific SPI */
      nums = 1;
    else
      nums = 100;  /* XXX figure out some good value */

    while (nums--)
    {
	if (sspi == tspi)  /* Specific SPI asked */
	  spi = tspi;
	else    /* Range specified */
	{
	    get_random_bytes((void *) &spi, sizeof(spi));
	    spi = sspi + (spi % (tspi - sspi));
	}
	  
	/* Don't allocate reserved SPIs.  */
	if (spi == SPI_LOCAL_USE ||
	    (spi >= SPI_RESERVED_MIN && spi <= SPI_RESERVED_MAX))
	  continue;
	else
	  spi = htonl(spi);

	/* Check whether we're using this SPI already */
	s = spltdb();
	tdbp = gettdb(spi, dst, sproto);
	splx(s);

	if (tdbp != (struct tdb *) NULL)
	  continue;

	MALLOC(tdbp, struct tdb *, sizeof(struct tdb), M_TDB, M_WAITOK);
	bzero((caddr_t) tdbp, sizeof(struct tdb));
	
	tdbp->tdb_spi = spi;
	bcopy(&dst->sa, &tdbp->tdb_dst.sa, SA_LEN(&dst->sa));
	bcopy(&src->sa, &tdbp->tdb_src.sa, SA_LEN(&src->sa));
	tdbp->tdb_sproto = sproto;
	tdbp->tdb_flags |= TDBF_INVALID;       /* Mark SA as invalid for now */
	tdbp->tdb_satype = SADB_SATYPE_UNSPEC;
	tdbp->tdb_established = time.tv_sec;
	tdbp->tdb_epoch = kernfs_epoch - 1;
	puttdb(tdbp);

	/* Setup a "silent" expiration (since TDBF_INVALID's set) */
	if (ipsec_keep_invalid > 0)
	{
		tdbp->tdb_flags |= TDBF_TIMER;
		tdbp->tdb_exp_timeout = time.tv_sec + ipsec_keep_invalid;
		tdb_expiration(tdbp, TDBEXP_EARLY | TDBEXP_TIMEOUT);
	}

	return spi;
    }

    (*errval) = EEXIST;
    return 0;
}

/*
 * Our hashing function needs to stir things with a non-zero random multiplier
 * so we cannot be DoS-attacked via choosing of the data to hash.
 */
INLINE int
tdb_hash(u_int32_t spi, union sockaddr_union *dst, u_int8_t proto)
{
    static u_int32_t mult1 = 0, mult2 = 0;
    u_int8_t *ptr = (u_int8_t *) dst;
    int i, shift;
    u_int64_t hash;
    int val32 = 0;

    while (mult1 == 0)
	mult1 = arc4random();
    while (mult2 == 0)
	mult2 = arc4random();

    hash = (spi ^ proto) * mult1;
    for (i = 0; i < SA_LEN(&dst->sa); i++)
    {
	val32 = (val32 << 8) | ptr[i];
	if (i % 4 == 3)
	{
	    hash ^= val32 * mult2;
	    val32 = 0;
	}
    }
    if (i % 4 != 0)
	hash ^= val32 * mult2;

    shift = ffs(tdb_hashmask + 1);
    while ((hash & ~tdb_hashmask) != 0)
      hash = (hash >> shift) ^ (hash & tdb_hashmask);

    return hash;
}

/*
 * An IPSP SAID is really the concatenation of the SPI found in the 
 * packet, the destination address of the packet and the IPsec protocol.
 * When we receive an IPSP packet, we need to look up its tunnel descriptor
 * block, based on the SPI in the packet and the destination address (which
 * is really one of our addresses if we received the packet!
 *
 * Caller is responsible for setting at least spltdb().
 */
struct tdb *
gettdb(u_int32_t spi, union sockaddr_union *dst, u_int8_t proto)
{
    u_int32_t hashval;
    struct tdb *tdbp;
    int s;

    if (spi == 0 && proto == 0)
    {
	/*
	 * tdb_bypass; a placeholder for bypass flows, allocate on
	 * first pass.
	 */
	if (tdb_bypass == NULL)
	{
	    s = spltdb();
	    MALLOC(tdb_bypass, struct tdb *, sizeof(struct tdb), M_TDB,
		   M_WAITOK);
	    tdb_count++;
	    splx(s);

	    bzero(tdb_bypass, sizeof(struct tdb));
	    tdb_bypass->tdb_satype = SADB_X_SATYPE_BYPASS;
	    tdb_bypass->tdb_established = time.tv_sec;
	    tdb_bypass->tdb_epoch = kernfs_epoch - 1;
	    tdb_bypass->tdb_flags = 0;

#ifdef INET
	    tdb_bypass->tdb_dst.sa.sa_family = AF_INET;
#elif INET6
	    tdb_bypass->tdb_dst.sa.sa_family = AF_INET6;
#endif

	    TAILQ_INIT(&tdb_bypass->tdb_bind_in);
	    TAILQ_INIT(&tdb_bypass->tdb_inp);
	}

	return tdb_bypass;
    }

    if (tdbh == NULL)
      return (struct tdb *) NULL;

    hashval = tdb_hash(spi, dst, proto);

    for (tdbp = tdbh[hashval]; tdbp != NULL; tdbp = tdbp->tdb_hnext)
      if ((tdbp->tdb_spi == spi) && 
	  !bcmp(&tdbp->tdb_dst, dst, SA_LEN(&dst->sa)) &&
	  (tdbp->tdb_sproto == proto))
	break;

    return tdbp;
}

#if DDB
void
tdb_hashstats()
{
    int i, cnt, buckets[16];
    struct tdb *tdbp;

    if (tdbh == NULL)
    {
	db_printf("no tdb hash table\n");
	return;
    }

    bzero (buckets, sizeof(buckets));
    for (i = 0; i <= tdb_hashmask; i++)
    {
	cnt = 0;
	for (tdbp = tdbh[i]; cnt < 16 && tdbp != NULL; tdbp = tdbp->tdb_hnext)
	  cnt++;
	buckets[cnt]++;
    }

    db_printf("tdb cnt\t\tbucket cnt\n");
    for (i = 0; i < 16; i++)
      if (buckets[i] > 0)
	db_printf("%d%c\t\t%d\n", i, i == 15 ? "+" : "", buckets[i]);
}
#endif	/* DDB */

/*
 * Caller is responsible for setting at least spltdb().
 */
int
tdb_walk(int (*walker)(struct tdb *, void *), void *arg)
{
    int i, rval = 0;
    struct tdb *tdbp, *next;

    if (tdbh == NULL)
        return ENOENT;

    for (i = 0; i <= tdb_hashmask; i++)
	for (tdbp = tdbh[i]; rval == 0 && tdbp != NULL; tdbp = next)
	{
	    next = tdbp->tdb_hnext;
	    rval = walker(tdbp, (void *)arg);
	}

    return rval;
}

struct flow *
get_flow(void)
{
    struct flow *flow;

    MALLOC(flow, struct flow *, sizeof(struct flow), M_TDB, M_WAITOK);
    bzero(flow, sizeof(struct flow));

    ipsec_in_use++;
    return flow;
}

/*
 * Called at splsoftclock().
 */
void
handle_expirations(void *arg)
{
    struct tdb *tdb;

    for (tdb = TAILQ_FIRST(&explist);
	 tdb && tdb->tdb_timeout <= time.tv_sec;
	 tdb = TAILQ_FIRST(&explist))
    {
	/* Hard expirations first */
	if ((tdb->tdb_flags & TDBF_TIMER) &&
	    (tdb->tdb_exp_timeout <= time.tv_sec))
	{
	    /* If it's an "invalid" TDB, do a silent expiration */
	    if (!(tdb->tdb_flags & TDBF_INVALID))
	      pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_HARD);
	    tdb_delete(tdb, 0, 0);
	    continue;
	}
	else
	  if ((tdb->tdb_flags & TDBF_FIRSTUSE) &&
	      (tdb->tdb_first_use + tdb->tdb_exp_first_use <= time.tv_sec))
	  {
	      pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_HARD);
	      tdb_delete(tdb, 0, 0);
	      continue;
	  }

	/* Soft expirations */
	if ((tdb->tdb_flags & TDBF_SOFT_TIMER) &&
	    (tdb->tdb_soft_timeout <= time.tv_sec))
	{
	    pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_SOFT);
	    tdb->tdb_flags &= ~TDBF_SOFT_TIMER;
	    tdb_expiration(tdb, TDBEXP_EARLY);
	}
	else
	  if ((tdb->tdb_flags & TDBF_SOFT_FIRSTUSE) &&
	      (tdb->tdb_first_use + tdb->tdb_soft_first_use <=
	       time.tv_sec))
	  {
	      pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_SOFT);
	      tdb->tdb_flags &= ~TDBF_SOFT_FIRSTUSE;
	      tdb_expiration(tdb, TDBEXP_EARLY);
	  }
    }

    /* If any tdb is left on the expiration queue, set the timer.  */
    if (tdb)
      timeout(handle_expirations, (void *) NULL, 
	      hz * (tdb->tdb_timeout - time.tv_sec));
}

/*
 * Ensure the tdb is in the right place in the expiration list.
 */
void
tdb_expiration(struct tdb *tdb, int flags)
{
    struct tdb *t, *former_expirer, *next_expirer;
    int will_be_first, sole_reason, early;
    u_int64_t next_timeout = 0;
    int s = spltdb();

    /*
     * If this is the local use SPI, this is an SPD entry, so don't setup any
     * timers.
     */
    if (ntohl(tdb->tdb_spi) == SPI_LOCAL_USE)
    {
	splx(s);
	return;
    }

    /* Find the earliest expiration.  */
    if ((tdb->tdb_flags & TDBF_FIRSTUSE) && tdb->tdb_first_use != 0 &&
	(next_timeout == 0 ||
	 next_timeout > tdb->tdb_first_use + tdb->tdb_exp_first_use))
	next_timeout = tdb->tdb_first_use + tdb->tdb_exp_first_use;
    if ((tdb->tdb_flags & TDBF_SOFT_FIRSTUSE) && tdb->tdb_first_use != 0 &&
	(next_timeout == 0 ||
	 next_timeout > tdb->tdb_first_use + tdb->tdb_soft_first_use))
	next_timeout = tdb->tdb_first_use + tdb->tdb_soft_first_use;
    if ((tdb->tdb_flags & TDBF_TIMER) &&
	(next_timeout == 0 || next_timeout > tdb->tdb_exp_timeout))
	next_timeout = tdb->tdb_exp_timeout;
    if ((tdb->tdb_flags & TDBF_SOFT_TIMER) &&
	(next_timeout == 0 || next_timeout > tdb->tdb_soft_timeout))
	next_timeout = tdb->tdb_soft_timeout;

    /* No change?  */
    if (next_timeout == tdb->tdb_timeout)
    {
      splx(s);
      return;
    }

    /*
     * Find out some useful facts: Will our tdb be first to expire?
     * Was our tdb the sole reason for the old timeout?
     */
    former_expirer = TAILQ_FIRST(&expclusterlist);
    next_expirer = TAILQ_NEXT(tdb, tdb_explink);
    will_be_first = (next_timeout != 0 &&
		     (former_expirer == NULL ||
		      next_timeout < former_expirer->tdb_timeout));
    sole_reason = (tdb == former_expirer &&
		   (next_expirer == NULL ||
		    tdb->tdb_timeout != next_expirer->tdb_timeout));

    /*
     * We need to untimeout if either:
     * - there is an expiration pending and the new timeout is earlier than
     *   what already exists or
     * - the existing first expiration is due to our old timeout value solely
     */
    if ((former_expirer != NULL && will_be_first) || sole_reason)
      untimeout(handle_expirations, (void *) NULL);

    /*
     * We need to timeout if we've been asked to and if either
     * - our tdb has a timeout and no former expiration exist or
     * - the new timeout is earlier than what already exists or
     * - the existing first expiration is due to our old timeout value solely
     *   and another expiration is in the pipe.
     */
    if ((flags & TDBEXP_TIMEOUT) &&
	(will_be_first || (sole_reason && next_expirer != NULL)))
      timeout(handle_expirations, (void *) NULL,
	      hz * ((will_be_first ? next_timeout :
		     next_expirer->tdb_timeout) - time.tv_sec));

    /* Our old position, if any, is not relevant anymore.  */
    if (tdb->tdb_timeout != 0)
    {
        if (tdb->tdb_expnext.tqe_prev != NULL)
	{
	    if (next_expirer && tdb->tdb_timeout == next_expirer->tdb_timeout)
	      TAILQ_INSERT_BEFORE(tdb, next_expirer, tdb_expnext);
	    TAILQ_REMOVE(&expclusterlist, tdb, tdb_expnext);
	    tdb->tdb_expnext.tqe_prev = NULL;
	}
	TAILQ_REMOVE(&explist, tdb, tdb_explink);
    }

    tdb->tdb_timeout = next_timeout;

    if (next_timeout == 0)
    {
      splx(s);
      return;
    }

    /*
     * Search front-to-back if we believe we will end up early, otherwise
     * back-to-front.
     */
    early = will_be_first || (flags & TDBEXP_EARLY);
    for (t = (early ? TAILQ_FIRST(&expclusterlist) :
	      TAILQ_LAST(&expclusterlist, expclusterlist_head));
	 t != NULL && (early ? (t->tdb_timeout <= next_timeout) : 
		       (t->tdb_timeout > next_timeout));
	 t = (early ? TAILQ_NEXT(t, tdb_expnext) :
	      TAILQ_PREV(t, expclusterlist_head, tdb_expnext)))
      ;
    if (t == (early ? TAILQ_FIRST(&expclusterlist) : NULL))
    {
	/* We are to become the first expiration.  */
	TAILQ_INSERT_HEAD(&expclusterlist, tdb, tdb_expnext);
	TAILQ_INSERT_HEAD(&explist, tdb, tdb_explink);
    }
    else
    {
	if (early)
	  t = (t ? TAILQ_PREV(t, expclusterlist_head, tdb_expnext) :
	       TAILQ_LAST(&expclusterlist, expclusterlist_head));
	if (TAILQ_NEXT(t, tdb_expnext))
	  TAILQ_INSERT_BEFORE(TAILQ_NEXT(t, tdb_expnext), tdb, tdb_explink);
	else
	  TAILQ_INSERT_TAIL(&explist, tdb, tdb_explink);
	if (t->tdb_timeout < next_timeout)
	  TAILQ_INSERT_AFTER(&expclusterlist, t, tdb, tdb_expnext);
    }

#ifdef DIAGNOSTIC
    /*
     * Check various invariants.
     */
    if (tdb->tdb_expnext.tqe_prev != NULL)
    {
	t = TAILQ_FIRST(&expclusterlist);
	if (t != tdb && t->tdb_timeout >= tdb->tdb_timeout)
	  panic("tdb_expiration: "
		"expclusterlist first link out of order (%p, %p)",
		tdb, t);
	t = TAILQ_PREV(tdb, expclusterlist_head, tdb_expnext);
	if (t != NULL && t->tdb_timeout >= tdb->tdb_timeout)
	  panic("tdb_expiration: "
		"expclusterlist prev link out of order (%p, %p)",
		tdb, t);
	else if (t == NULL && tdb != TAILQ_FIRST(&expclusterlist))
	  panic("tdb_expiration: "
		"expclusterlist first link out of order (%p, %p)",
		tdb, TAILQ_FIRST(&expclusterlist));
	t = TAILQ_NEXT(tdb, tdb_expnext);
	if (t != NULL && t->tdb_timeout <= tdb->tdb_timeout)
	  panic("tdb_expiration: "
		"expclusterlist next link out of order (%p, %p)",
		tdb, t);
	else if (t == NULL &&
		 tdb != TAILQ_LAST(&expclusterlist, expclusterlist_head))
	  panic("tdb_expiration: "
		"expclusterlist last link out of order (%p, %p)",
		tdb, TAILQ_LAST(&expclusterlist, expclusterlist_head));
	t = TAILQ_LAST(&expclusterlist, expclusterlist_head);
	if (t != tdb && t->tdb_timeout <= tdb->tdb_timeout)
	  panic("tdb_expiration: "
		"expclusterlist last link out of order (%p, %p)",
		tdb, t);
    }
    t = TAILQ_FIRST(&explist);
    if (t != NULL && t->tdb_timeout > tdb->tdb_timeout)
      panic("tdb_expiration: explist first link out of order (%p, %p)", tdb,
	    t);
    t = TAILQ_PREV(tdb, explist_head, tdb_explink);
    if (t != NULL && t->tdb_timeout > tdb->tdb_timeout)
      panic("tdb_expiration: explist prev link out of order (%p, %p)", tdb, t);
    else if (t == NULL && tdb != TAILQ_FIRST(&explist))
      panic("tdb_expiration: explist first link out of order (%p, %p)", tdb,
	    TAILQ_FIRST(&explist));
    t = TAILQ_NEXT(tdb, tdb_explink);
    if (t != NULL && t->tdb_timeout < tdb->tdb_timeout)
      panic("tdb_expiration: explist next link out of order (%p, %p)", tdb, t);
    else if (t == NULL && tdb != TAILQ_LAST(&explist, explist_head))
      panic("tdb_expiration: explist last link out of order (%p, %p)", tdb,
	    TAILQ_LAST(&explist, explist_head));
    t = TAILQ_LAST(&explist, explist_head);
    if (t != tdb && t->tdb_timeout < tdb->tdb_timeout)
      panic("tdb_expiration: explist last link out of order (%p, %p)", tdb, t);
#endif

    splx(s);
}

/*
 * Caller is responsible for setting at least spltdb().
 */
struct flow *
find_flow(union sockaddr_union *src, union sockaddr_union *srcmask,
	  union sockaddr_union *dst, union sockaddr_union *dstmask,
	  u_int8_t proto, struct tdb *tdb, int ingress)
{
    struct flow *flow;

    if (ingress)
      flow = tdb->tdb_access;
    else
      flow = tdb->tdb_flow;

    for (; flow; flow = flow->flow_next)
      if (!bcmp(&src->sa, &flow->flow_src.sa, SA_LEN(&src->sa)) &&
	  !bcmp(&dst->sa, &flow->flow_dst.sa, SA_LEN(&dst->sa)) &&
	  !bcmp(&srcmask->sa, &flow->flow_srcmask.sa, SA_LEN(&srcmask->sa)) &&
	  !bcmp(&dstmask->sa, &flow->flow_dstmask.sa, SA_LEN(&dstmask->sa)) &&
	  (proto == flow->flow_proto))
	return flow;

    return (struct flow *) NULL;
}

/*
 * Caller is responsible for setting at least spltdb().
 */
struct flow *
find_global_flow(union sockaddr_union *src, union sockaddr_union *srcmask,
		 union sockaddr_union *dst, union sockaddr_union *dstmask,
		 u_int8_t proto)
{
    struct flow *flow;
    struct tdb *tdb;
    int i;

    if (tdbh == NULL)
      return (struct flow *) NULL;

    if (tdb_bypass != NULL)
      if ((flow = find_flow(src, srcmask, dst, dstmask, proto,
			    tdb_bypass, FLOW_EGRESS)) != (struct flow *) NULL)
	return flow;

    for (i = 0; i <= tdb_hashmask; i++)
    {
	for (tdb = tdbh[i]; tdb != NULL; tdb = tdb->tdb_hnext)
	  if ((flow = find_flow(src, srcmask, dst, dstmask, proto,
				tdb, FLOW_EGRESS)) != (struct flow *) NULL)
	    return flow;
    }
    return (struct flow *) NULL;
}

/*
 * Caller is responsible for spltdb().
 */
void
tdb_rehash(void)
{
    struct tdb **new_tdbh, *tdbp, *tdbnp;
    u_int i, old_hashmask = tdb_hashmask;
    u_int32_t hashval;

    tdb_hashmask = (tdb_hashmask << 1) | 1;
    MALLOC(new_tdbh, struct tdb **, sizeof(struct tdb *) * (tdb_hashmask + 1),
	   M_TDB, M_WAITOK);
    bzero(new_tdbh, sizeof(struct tdb *) * (tdb_hashmask + 1));
    for (i = 0; i <= old_hashmask; i++)
      for (tdbp = tdbh[i]; tdbp != NULL; tdbp = tdbnp)
      {
	  tdbnp = tdbp->tdb_hnext;
      	  hashval = tdb_hash(tdbp->tdb_spi, &tdbp->tdb_dst, tdbp->tdb_sproto);
	  tdbp->tdb_hnext = new_tdbh[hashval];
	  new_tdbh[hashval] = tdbp;
      }

    FREE(tdbh, M_TDB);
    tdbh = new_tdbh;
}

/*
 * Add TDB in the hash table.
 */
void
puttdb(struct tdb *tdbp)
{
    u_int32_t hashval;
    int s = spltdb();

    if (tdbh == NULL)
    {
	MALLOC(tdbh, struct tdb **, sizeof(struct tdb *) * (tdb_hashmask + 1),
	       M_TDB, M_WAITOK);
	bzero(tdbh, sizeof(struct tdb *) * (tdb_hashmask + 1));
    }

    hashval = tdb_hash(tdbp->tdb_spi, &tdbp->tdb_dst, tdbp->tdb_sproto);
    
    /*
     * Rehash if this tdb would cause a bucket to have more than two items
     * and if the number of tdbs exceed 10% of the bucket count.  This
     * number is arbitratily chosen and is just a measure to not keep rehashing
     * when adding and removing tdbs which happens to always end up in the
     * same bucket, which is not uncommon when doing manual keying.
     */
    if (tdbh[hashval] != NULL && tdbh[hashval]->tdb_hnext != NULL &&
	tdb_count * 10 > tdb_hashmask + 1)
    {
	tdb_rehash();
	hashval = tdb_hash(tdbp->tdb_spi, &tdbp->tdb_dst, tdbp->tdb_sproto);
    }
    tdbp->tdb_hnext = tdbh[hashval];
    tdbh[hashval] = tdbp;
    tdb_count++;
    splx(s);
}

/*
 * Caller is responsible for setting at least spltdb().
 */
void
put_flow(struct flow *flow, struct tdb *tdb, int ingress)
{
    if (ingress)
    {
	flow->flow_next = tdb->tdb_access;
	tdb->tdb_access = flow;
    }
    else
    {
	flow->flow_next = tdb->tdb_flow;
	tdb->tdb_flow = flow;
    }

    if (flow->flow_next)
      flow->flow_next->flow_prev = flow;

    flow->flow_sa = tdb;
    flow->flow_prev = (struct flow *) NULL;
}

/*
 * Caller is responsible for setting at least spltdb().
 */
void
delete_flow(struct flow *flow, struct tdb *tdb, int ingress)
{
    if (tdb)
    {
	if (ingress && (tdb->tdb_access == flow))
	    tdb->tdb_access = flow->flow_next;
	else
	  if (!ingress && (tdb->tdb_flow == flow))
	    tdb->tdb_flow = flow->flow_next;

	if (flow->flow_prev)
	  flow->flow_prev->flow_next = flow->flow_next;

	if (flow->flow_next)
	  flow->flow_next->flow_prev = flow->flow_prev;
    }

    if (!ingress)
      ipsec_in_use--;

    FREE(flow, M_TDB);
}

/*
 * Caller is responsible to set at least spltdb().
 */
void
tdb_delete(struct tdb *tdbp, int delchain, int expflags)
{
    struct tdb *tdbpp, *tdbpn;
    struct inpcb *inp;
    u_int32_t hashval = tdbp->tdb_sproto + tdbp->tdb_spi;
    int s;

    /* When deleting the bypass tdb, skip the hash table code. */
    if (tdbp == tdb_bypass && tdbp != NULL)
    {
	s = spltdb();
	delchain = 0;
	goto skip_hash;
    }

    if (tdbh == NULL)
      return;

    hashval = tdb_hash(tdbp->tdb_spi, &tdbp->tdb_dst, tdbp->tdb_sproto);

    s = spltdb();
    if (tdbh[hashval] == tdbp)
    {
	tdbpp = tdbp;
	tdbh[hashval] = tdbp->tdb_hnext;
    }
    else
      for (tdbpp = tdbh[hashval]; tdbpp != NULL; tdbpp = tdbpp->tdb_hnext)
	if (tdbpp->tdb_hnext == tdbp)
	{
	    tdbpp->tdb_hnext = tdbp->tdb_hnext;
	    tdbpp = tdbp;
	    break;
	}

    tdbp->tdb_hnext = NULL;

 skip_hash:
    /*
     * If there was something before us in the chain pointing to us,
     * make it point nowhere.
     */
    if ((tdbp->tdb_inext) &&
	(tdbp->tdb_inext->tdb_onext == tdbp))
      tdbp->tdb_inext->tdb_onext = NULL;

    /* 
     * If there was something after us in the chain pointing to us,
     * make it point nowhere.
     */
    if ((tdbp->tdb_onext) &&
	(tdbp->tdb_onext->tdb_inext == tdbp))
      tdbp->tdb_onext->tdb_inext = NULL;
    
    tdbpn = tdbp->tdb_onext;
    tdbp->tdb_inext = tdbp->tdb_onext = NULL;

    if (tdbp->tdb_xform)
    {
      	(*(tdbp->tdb_xform->xf_zeroize))(tdbp);
	tdbp->tdb_xform = NULL;
    }

    while (tdbp->tdb_access)
      delete_flow(tdbp->tdb_access, tdbp, FLOW_INGRESS);

    while (tdbp->tdb_flow)
    {
        /* Delete the flow and the routing entry that goes with it. */ 
        struct sockaddr_encap encapdst, encapnetmask;

        bzero(&encapdst, sizeof(struct sockaddr_encap));
        bzero(&encapnetmask, sizeof(struct sockaddr_encap));

        encapdst.sen_family = PF_KEY;
        encapnetmask.sen_family = PF_KEY;

	switch (tdbp->tdb_flow->flow_src.sa.sa_family)
	{
	    case AF_INET:
		encapdst.sen_len = SENT_IP4_LEN;
		encapdst.sen_type = SENT_IP4;
		encapdst.sen_ip_src = tdbp->tdb_flow->flow_src.sin.sin_addr;
		encapdst.sen_ip_dst = tdbp->tdb_flow->flow_dst.sin.sin_addr;
		encapdst.sen_proto = tdbp->tdb_flow->flow_proto;
		encapdst.sen_sport = tdbp->tdb_flow->flow_src.sin.sin_port;
		encapdst.sen_dport = tdbp->tdb_flow->flow_dst.sin.sin_port;

		encapnetmask.sen_ip_src = tdbp->tdb_flow->flow_srcmask.sin.sin_addr;
		encapnetmask.sen_ip_dst = tdbp->tdb_flow->flow_dstmask.sin.sin_addr;

		/* Mask transport protocol and ports if applicable */
		if (tdbp->tdb_flow->flow_proto)
		{
		    encapnetmask.sen_proto = 0xff;
		    if (tdbp->tdb_flow->flow_src.sin.sin_port)
		      encapnetmask.sen_sport = 0xffff;
		    if (tdbp->tdb_flow->flow_dst.sin.sin_port)
		      encapnetmask.sen_dport = 0xffff;
		}
		break;

#if INET6
	    case AF_INET6:
		encapdst.sen_len = SENT_IP6_LEN;
		encapdst.sen_type = SENT_IP6;
		encapdst.sen_ip6_src = tdbp->tdb_flow->flow_src.sin6.sin6_addr;
		encapdst.sen_ip6_dst = tdbp->tdb_flow->flow_dst.sin6.sin6_addr;
		encapdst.sen_ip6_proto = tdbp->tdb_flow->flow_proto;
		encapdst.sen_ip6_sport = tdbp->tdb_flow->flow_src.sin6.sin6_port;
		encapdst.sen_ip6_dport = tdbp->tdb_flow->flow_dst.sin6.sin6_port;

		encapnetmask.sen_ip6_src = tdbp->tdb_flow->flow_srcmask.sin6.sin6_addr;
		encapnetmask.sen_ip6_dst = tdbp->tdb_flow->flow_dstmask.sin6.sin6_addr;

		/* Mask transport protocol and ports if applicable */
		if (tdbp->tdb_flow->flow_proto)
		{
		    encapnetmask.sen_ip6_proto = 0xff;
		    if (tdbp->tdb_flow->flow_src.sin6.sin6_port)
		      encapnetmask.sen_ip6_sport = 0xffff;
		    if (tdbp->tdb_flow->flow_dst.sin6.sin6_port)
		      encapnetmask.sen_ip6_dport = 0xffff;
		}
		break;
#endif /* INET6 */

	    default:
#ifdef DIAGNOSTIC
		panic("tdb_delete(): SA %s/%08x/%d has flow of unknown type %d", ipsp_address(tdbp->tdb_dst), ntohl(tdbp->tdb_spi), tdbp->tdb_sproto, tdbp->tdb_flow->flow_src.sa.sa_family);
#endif /* DIAGNOSTIC */		
		delete_flow(tdbp->tdb_flow, tdbp, FLOW_EGRESS);
		continue;
	}

	/* Always the same type for address and netmask */
	encapnetmask.sen_len = encapdst.sen_len;
	encapnetmask.sen_type = encapdst.sen_type;

        rtrequest(RTM_DELETE, (struct sockaddr *) &encapdst,
                  (struct sockaddr *) 0,
                  (struct sockaddr *) &encapnetmask,
                  0, (struct rtentry **) 0);

        delete_flow(tdbp->tdb_flow, tdbp, FLOW_EGRESS);
    }

    /* Cleanup SA-Bindings */
    for (tdbpp = TAILQ_FIRST(&tdbp->tdb_bind_in); tdbpp;
	 tdbpp = TAILQ_FIRST(&tdbp->tdb_bind_in))
    {
        TAILQ_REMOVE(&tdbpp->tdb_bind_in, tdbpp, tdb_bind_in_next);
	tdbpp->tdb_bind_out = NULL;
    }

    /* Cleanup inp references */
    for (inp = TAILQ_FIRST(&tdbp->tdb_inp); inp;
	 inp = TAILQ_FIRST(&tdbp->tdb_inp))
    {
        TAILQ_REMOVE(&tdbp->tdb_inp, inp, inp_tdb_next);
	inp->inp_tdb = NULL;
    }

    if (tdbp->tdb_bind_out)
      TAILQ_REMOVE(&tdbp->tdb_bind_out->tdb_bind_in, tdbp, tdb_bind_in_next);

    /* Remove us from the expiration lists.  */
    if (tdbp->tdb_timeout != 0)
    {
        tdbp->tdb_flags &= ~(TDBF_FIRSTUSE | TDBF_SOFT_FIRSTUSE | TDBF_TIMER |
			     TDBF_SOFT_TIMER);
	tdb_expiration(tdbp, expflags);
    }

    if (tdbp->tdb_srcid)
    {
      	FREE(tdbp->tdb_srcid, M_XDATA);
	tdbp->tdb_srcid = NULL;
    }

    if (tdbp->tdb_dstid)
    {
      	FREE(tdbp->tdb_dstid, M_XDATA);
	tdbp->tdb_dstid = NULL;
    }

    /* If we're deleting the bypass tdb, reset the variable. */
    if (tdbp == tdb_bypass)
      tdb_bypass = NULL;

    FREE(tdbp, M_TDB);
    tdb_count--;

    if (delchain && tdbpn)
      tdb_delete(tdbpn, delchain, expflags);

    splx(s);
}

/*
 * Initialize a TDB structure.
 */
int
tdb_init(struct tdb *tdbp, u_int16_t alg, struct ipsecinit *ii)
{
    struct xformsw *xsp;

    /* Record establishment time */
    tdbp->tdb_established = time.tv_sec;
    tdbp->tdb_epoch = kernfs_epoch - 1;

    /* Init Incoming SA-Binding Queues */
    TAILQ_INIT(&tdbp->tdb_bind_in);
    TAILQ_INIT(&tdbp->tdb_inp);

    for (xsp = xformsw; xsp < xformswNXFORMSW; xsp++)
      if (xsp->xf_type == alg)
	return (*(xsp->xf_init))(tdbp, xsp, ii);

    DPRINTF(("tdb_init(): no alg %d for spi %08x, addr %s, proto %d\n", 
	     alg, ntohl(tdbp->tdb_spi), ipsp_address(tdbp->tdb_dst),
	     tdbp->tdb_sproto));

    return EINVAL;
}

/*
 * Used by kernfs.
 */
int
ipsp_kern(int off, char **bufp, int len)
{
    static char buffer[IPSEC_KERNFS_BUFSIZE];
    struct flow *flow;
    struct tdb *tdb, *tdbp;
    int l, i, s;

    if (off == 0)
      kernfs_epoch++;
    
    if (bufp == NULL || tdbh == NULL)
      return 0;

    bzero(buffer, IPSEC_KERNFS_BUFSIZE);

    *bufp = buffer;
    
    for (i = 0; i <= tdb_hashmask; i++)
    {
        s = spltdb();
	for (tdb = tdbh[i]; tdb; tdb = tdb->tdb_hnext)
	  if (tdb->tdb_epoch != kernfs_epoch)
	  {
	      tdb->tdb_epoch = kernfs_epoch;

	      l = sprintf(buffer,
			  "SPI = %08x, Destination = %s, Sproto = %u\n",
			  ntohl(tdb->tdb_spi),
			  ipsp_address(tdb->tdb_dst), tdb->tdb_sproto);

	      l += sprintf(buffer + l, "\tEstablished %d seconds ago\n",
			   time.tv_sec - tdb->tdb_established);

	      l += sprintf(buffer + l, "\tSource = %s",
			   ipsp_address(tdb->tdb_src));

	      if (tdb->tdb_proxy.sa.sa_family)
		l += sprintf(buffer + l, ", Proxy = %s\n",
			     ipsp_address(tdb->tdb_proxy));
	      else
		l += sprintf(buffer + l, "\n");

	      l += sprintf(buffer + l, "\tFlags (%08x) = <", tdb->tdb_flags);

	      if ((tdb->tdb_flags & ~(TDBF_TIMER | TDBF_BYTES |
				      TDBF_ALLOCATIONS | TDBF_FIRSTUSE |
				      TDBF_SOFT_TIMER | TDBF_SOFT_BYTES |
				      TDBF_SOFT_FIRSTUSE |
				      TDBF_SOFT_ALLOCATIONS)) == 0)
		l += sprintf(buffer + l, "none>\n");
	      else
	      {
		  /* We can reuse variable 'i' here, since we're not looping */
		  i = 0;

		  if (tdb->tdb_flags & TDBF_UNIQUE)
		  {
		      if (i)
			l += sprintf(buffer + l, ", ");
		      else
			i = 1;

		      l += sprintf(buffer + l, "unique");
		      i = 1;
		  }

		  if (tdb->tdb_flags & TDBF_INVALID)
		  {
		      if (i)
			l += sprintf(buffer + l, ", ");
		      else
			i = 1;

		      l += sprintf(buffer + l, "invalid");
		  }

		  if (tdb->tdb_flags & TDBF_HALFIV)
		  {
		      if (i)
			l += sprintf(buffer + l, ", ");
		      else
			i = 1;

		      l += sprintf(buffer + l, "halfiv");
		  }

		  if (tdb->tdb_flags & TDBF_PFS)
		  {
		      if (i)
			l += sprintf(buffer + l, ", ");
		      else
			i = 1;

		      l += sprintf(buffer + l, "pfs");
		  }

		  if (tdb->tdb_flags & TDBF_TUNNELING)
		  {
		      if (i)
			l += sprintf(buffer + l, ", ");
		      else
			i = 1;

		      l += sprintf(buffer + l, "tunneling");
		  }

		  if (tdb->tdb_flags & TDBF_NOREPLAY)
		  {
		      if (i)
			l += sprintf(buffer + l, ", ");
		      else
			i = 1;

		      l += sprintf(buffer + l, "noreplay");
		  }

		  if (tdb->tdb_flags & TDBF_RANDOMPADDING)
		  {
		      if (i)
			l += sprintf(buffer + l, ", ");
		      else
			i = 1;

		      l += sprintf(buffer + l, "random padding");
		  }

		  l += sprintf(buffer + l, ">\n");
	      }

	      l += sprintf(buffer + l, "\tCrypto ID: %qu\n", tdb->tdb_cryptoid);

	      if (tdb->tdb_xform)
		l += sprintf(buffer + l, "\txform = <%s>\n", 
			     tdb->tdb_xform->xf_name);

	      if (tdb->tdb_encalgxform)
		l += sprintf(buffer + l, "\t\tEncryption = <%s>\n",
			     tdb->tdb_encalgxform->name);

	      if (tdb->tdb_authalgxform)
		l += sprintf(buffer + l, "\t\tAuthentication = <%s>\n",
			     tdb->tdb_authalgxform->name);

	      if (tdb->tdb_interface)
		l += sprintf(buffer + l, "\tAssociated interface = <%s>\n",
			     ((struct ifnet *) tdb->tdb_interface)->if_xname);

	      if (tdb->tdb_bind_out)
		l += sprintf(buffer + l,
			     "\tBound SA: SPI = %08x, "
			     "Destination = %s, Sproto = %u\n",
			     ntohl(tdb->tdb_bind_out->tdb_spi),
			     ipsp_address(tdb->tdb_bind_out->tdb_dst),
			     tdb->tdb_bind_out->tdb_sproto);
	      for (i = 0, tdbp = TAILQ_FIRST(&tdb->tdb_bind_in); tdbp;
		   tdbp = TAILQ_NEXT(tdbp, tdb_bind_in_next))
		i++;

	      if (i > 0)
		l += sprintf(buffer + l,
			     "\tReferenced by %d incoming SA%s\n",
			     i, i == 1 ? "" : "s");

	      if (tdb->tdb_onext)
		l += sprintf(buffer + l,
			     "\tNext SA: SPI = %08x, "
			     "Destination = %s, Sproto = %u\n",
			     ntohl(tdb->tdb_onext->tdb_spi),
			     ipsp_address(tdb->tdb_onext->tdb_dst),
			     tdb->tdb_onext->tdb_sproto);

	      if (tdb->tdb_inext)
		l += sprintf(buffer + l,
			     "\tPrevious SA: SPI = %08x, "
			     "Destination = %s, Sproto = %u\n",
			     ntohl(tdb->tdb_inext->tdb_spi),
			     ipsp_address(tdb->tdb_inext->tdb_dst),
			     tdb->tdb_inext->tdb_sproto);

	      for (i = 0, flow = tdb->tdb_flow; flow; flow = flow->flow_next)
		i++;

	      l+= sprintf(buffer + l, "\tCurrently used by %d flows\n", i);

	      for (i = 0, flow = tdb->tdb_access; flow; flow = flow->flow_next)
		i++;

	      l+= sprintf(buffer + l,
			  "\t%d ingress flows specified\n", i);

	      l += sprintf(buffer + l, "\t%u flows have used this SA\n",
			   tdb->tdb_cur_allocations);
	    
	      l += sprintf(buffer + l, "\t%qu bytes processed by this SA\n",
			 tdb->tdb_cur_bytes);
	    
	      l += sprintf(buffer + l, "\tExpirations:\n");

	      if (tdb->tdb_flags & TDBF_TIMER)
		l += sprintf(buffer + l,
			     "\t\tHard expiration(1) in %qu seconds\n",
			     tdb->tdb_exp_timeout - time.tv_sec);
	    
	      if (tdb->tdb_flags & TDBF_SOFT_TIMER)
		l += sprintf(buffer + l,
			     "\t\tSoft expiration(1) in %qu seconds\n",
			     tdb->tdb_soft_timeout - time.tv_sec);
	    
	      if (tdb->tdb_flags & TDBF_BYTES)
		l += sprintf(buffer + l,
			     "\t\tHard expiration after %qu bytes\n",
			     tdb->tdb_exp_bytes);
	    
	      if (tdb->tdb_flags & TDBF_SOFT_BYTES)
		l += sprintf(buffer + l,
			     "\t\tSoft expiration after %qu bytes\n",
			     tdb->tdb_soft_bytes);

	      if (tdb->tdb_flags & TDBF_ALLOCATIONS)
		l += sprintf(buffer + l,
			     "\t\tHard expiration after %u flows\n",
			     tdb->tdb_exp_allocations);
	    
	      if (tdb->tdb_flags & TDBF_SOFT_ALLOCATIONS)
		l += sprintf(buffer + l,
			     "\t\tSoft expiration after %u flows\n",
			     tdb->tdb_soft_allocations);

	      if (tdb->tdb_flags & TDBF_FIRSTUSE)
	      {
		  if (tdb->tdb_first_use)
		    l += sprintf(buffer + l,
				 "\t\tHard expiration(2) in %qu seconds\n",
				 (tdb->tdb_first_use +
				  tdb->tdb_exp_first_use) - time.tv_sec);
		  else
		    l += sprintf(buffer + l,
				 "\t\tHard expiration in %qu seconds "
				 "after first use\n",
				 tdb->tdb_exp_first_use);
	      }

	      if (tdb->tdb_flags & TDBF_SOFT_FIRSTUSE)
	      {
		  if (tdb->tdb_first_use)
		    l += sprintf(buffer + l,
				 "\t\tSoft expiration(2) in %qu seconds\n",
				 (tdb->tdb_first_use +
				  tdb->tdb_soft_first_use) - time.tv_sec);
		  else
		    l += sprintf(buffer + l,
				 "\t\tSoft expiration in %qu seconds "
				 "after first use\n",
				 tdb->tdb_soft_first_use);
	      }

	      if (!(tdb->tdb_flags &
		    (TDBF_TIMER | TDBF_SOFT_TIMER | TDBF_BYTES |
		     TDBF_SOFT_ALLOCATIONS | TDBF_ALLOCATIONS |
		     TDBF_SOFT_BYTES | TDBF_FIRSTUSE | TDBF_SOFT_FIRSTUSE)))
		l += sprintf(buffer + l, "\t\t(none)\n");

	      l += sprintf(buffer + l, "\n");

	      splx(s);
	      return l;
	  }
	splx(s);
    }
    return 0;
}

char *
inet_ntoa4(struct in_addr ina)
{
    static char buf[4][4 * sizeof "123" + 4];
    unsigned char *ucp = (unsigned char *) &ina;
    static int i = 3;
 
    i = (i + 1) % 4;
    sprintf(buf[i], "%d.%d.%d.%d", ucp[0] & 0xff, ucp[1] & 0xff,
            ucp[2] & 0xff, ucp[3] & 0xff);
    return (buf[i]);
}

char *
ipsp_address(union sockaddr_union sa)
{
    switch (sa.sa.sa_family)
    {
	case AF_INET:
	    return inet_ntoa4(sa.sin.sin_addr);

#if INET6
	case AF_INET6:
	    return ip6_sprintf(sa.sin6.sin6_addr);
#endif /* INET6 */

	default:
	    return "(unknown address family)";
    }
}

/*
 * Loop over a tdb chain, taking into consideration protocol tunneling. The
 * fourth argument is set if the first encapsulation header is already in
 * place.
 */
int
ipsp_process_packet(struct mbuf *m, struct tdb *tdb, int af, int tunalready)
{
    int i, off, error;
    struct mbuf *mp;

#ifdef INET
    struct ip *ip;
#endif /* INET */
#ifdef INET6
    struct ip6_hdr *ip6;
#endif /* INET6 */

    /* Check that the transform is allowed by the administrator */
    if ((tdb->tdb_sproto == IPPROTO_ESP && !esp_enable) ||
	(tdb->tdb_sproto == IPPROTO_AH && !ah_enable))
    {
	DPRINTF(("ipsp_process_packet(): IPSec outbound packet dropped due to policy\n"));
	m_freem(m);
	return EHOSTUNREACH;
    }

    /* Sanity check */
    if (!tdb->tdb_xform)
    {
	DPRINTF(("ipsp_process_packet(): uninitialized TDB\n"));
	m_freem(m);
	return EHOSTUNREACH;
    }

    /* Check if the SPI is invalid */
    if (tdb->tdb_flags & TDBF_INVALID)
    {
	DPRINTF(("ipsp_process_packet(): attempt to use invalid SA %s/%08x/%u\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi), tdb->tdb_sproto));
	m_freem(m);
	return ENXIO;
    }

    /* Check that the network protocol is supported */
    switch (tdb->tdb_dst.sa.sa_family)
    {
#ifdef INET
	case AF_INET:
	    break;
#endif /* INET */

#ifdef INET6
	case AF_INET6:
	    break;
#endif /* INET6 */

	default:
	    DPRINTF(("ipsp_process_packet(): attempt to use SA %s/%08x/%u for protocol family %d\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi), tdb->tdb_sproto, tdb->tdb_dst.sa.sa_family));
	    m_freem(m);
	    return ENXIO;
    }

    /* Register first use if applicable, setup relevant expiration timer */
    if (tdb->tdb_first_use == 0)
    {
	tdb->tdb_first_use = time.tv_sec;
	tdb_expiration(tdb, TDBEXP_TIMEOUT);
    }

    /*
     * Check for tunneling if we don't have the first header in place.
     * When doing Ethernet-over-IP, we are handed an already-encapsulated
     * frame, so we don't need to re-encapsulate.
     */
    if (tunalready == 0)
    {
	/*
	 * If the target protocol family is different, we know we'll be
	 * doing tunneling.
	 */
	if (af == tdb->tdb_dst.sa.sa_family)
	{
#ifdef INET
	    if (af == AF_INET)
	      i = sizeof(struct ip);
#endif /* INET */

#ifdef INET6
	    if (af == AF_INET6)
	      i = sizeof(struct ip6_hdr);
#endif /* INET6 */

	    /* Bring the network header in the first mbuf */
	    if (m->m_len < i)
	    {
		if ((m = m_pullup(m, i)) == 0)
		  return ENOBUFS;
	    }

#ifdef INET
	    ip = mtod(m, struct ip *);
#endif /* INET */

#ifdef INET6
	    ip6 = mtod(m, struct ip6_hdr *);
#endif /* INET6 */
	}

	/* Do the appropriate encapsulation, if necessary */
	if ((tdb->tdb_dst.sa.sa_family != af) || /* PF mismatch */
	    (tdb->tdb_flags & TDBF_TUNNELING) || /* Tunneling requested */
	    (tdb->tdb_xform->xf_type == XF_IP4) || /* ditto */
#ifdef INET
	    ((tdb->tdb_dst.sa.sa_family == AF_INET) &&
	     (tdb->tdb_dst.sin.sin_addr.s_addr != INADDR_ANY) &&
	     (tdb->tdb_dst.sin.sin_addr.s_addr != ip->ip_dst.s_addr)) ||
#endif /* INET */
#ifdef INET6
	    ((tdb->tdb_dst.sa.sa_family == AF_INET6) &&
	     (!IN6_IS_ADDR_UNSPECIFIED(&tdb->tdb_dst.sin6.sin6_addr)) &&
	     (!IN6_ARE_ADDR_EQUAL(&tdb->tdb_dst.sin6.sin6_addr,
				  &ip6->ip6_dst))) ||
#endif /* INET6 */
	    0)
	{
#ifdef INET
	    /* Fix IPv4 header checksum and length */
	    if (af == AF_INET)
	    {
		if ((m = m_pullup(m, sizeof(struct ip))) == 0)
		  return ENOBUFS;

		ip = mtod(m, struct ip *);
		ip->ip_len = htons(m->m_pkthdr.len);
		ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
	    }
#endif /* INET */

#ifdef INET6
	    /* Fix IPv6 header payload length */
	    if (af == AF_INET6)
	    {
		if ((m = m_pullup(m, sizeof(struct ip6_hdr))) == 0)
		  return ENOBUFS;

		ip6 = mtod(m, struct ip6_hdr *);
		ip6->ip6_plen = htons(m->m_pkthdr.len);
	    }
#endif /* INET6 */

	    /* Encapsulate -- the last two arguments are unused */
	    error = ipip_output(m, tdb, &mp, 0, 0);
	    if ((mp == NULL) && (!error))
	      error = EFAULT;
	    if (error)
	    {
		if (mp)
		{
		    m_freem(mp);
		    mp = NULL;
		}

		return error;
	    }

	    m = mp;
	    mp = NULL;
	}

	/* We may be done with this TDB */
	if (tdb->tdb_xform->xf_type == XF_IP4)
	  return ipsp_process_done(m, tdb);
    }
    else
    {
	/*
	 * If this is just an IP-IP TDB and we're told there's already an
	 * encapsulation header, move on.
	 */
	if (tdb->tdb_xform->xf_type == XF_IP4)
	  return ipsp_process_done(m, tdb);
    }

    /* Extract some information off the headers */
    switch (tdb->tdb_dst.sa.sa_family)
    {
#ifdef INET
	case AF_INET:
	    ip = mtod(m, struct ip *);
	    i = ip->ip_hl << 2;
	    off = offsetof(struct ip, ip_p);
	    break;
#endif /* INET */

#ifdef INET6
	case AF_INET6:
	    ip6 = mtod(m, struct ip6_hdr *);
	    i = sizeof(struct ip6_hdr);
	    off = offsetof(struct ip6_hdr, ip6_nxt);
	    break;
#endif /* INET6 */
    }

    /* Invoke the IPsec transform */
    return (*(tdb->tdb_xform->xf_output))(m, tdb, NULL, i, off);
}

/*
 * Called by the IPsec output transform callbacks, to transmit the packet
 * or do further processing, as necessary.
 */
int
ipsp_process_done(struct mbuf *m, struct tdb *tdb)
{
#ifdef INET
    struct ip *ip;
#endif /* INET */

#ifdef INET6
    struct ip6_hdr *ip6;
#endif /* INET6 */

    switch (tdb->tdb_dst.sa.sa_family)
    {
#ifdef INET
	case AF_INET:
	    /* Fix the header length, for AH processing */
	    if (tdb->tdb_dst.sa.sa_family == AF_INET)
	    {
		ip = mtod(m, struct ip *);
		ip->ip_len = htons(m->m_pkthdr.len);
	    }
	    break;
#endif /* INET */

#ifdef INET6
	case AF_INET6:
	    /* Fix the header length, for AH processing */
	    if (tdb->tdb_dst.sa.sa_family == AF_INET6)
	    {
		ip6 = mtod(m, struct ip6_hdr *);
		ip6->ip6_plen = htons(m->m_pkthdr.len);
	    }
	    break;
#endif /* INET6 */

	default:
	    m_freem(m);
	    DPRINTF(("ipsp_process_done(): unknown protocol family (%d)\n",
		     tdb->tdb_dst.sa.sa_family));
	    return ENXIO;
    }

    /* If there's another TDB to apply, do so. */
    if (tdb->tdb_onext)
      return ipsp_process_packet(m, tdb->tdb_onext,
				 tdb->tdb_onext->tdb_dst.sa.sa_family, 0);

    /*
     * If we're done with IPsec processing, transmit the packet using the
     * appropriate network protocol (IP or IPv6).
     */
    switch (tdb->tdb_dst.sa.sa_family)
    {
#ifdef INET
	case AF_INET:
	    NTOHS(ip->ip_len);
	    NTOHS(ip->ip_off);
	    ip->ip_sum = in_cksum(m, ip->ip_hl << 2); /* Fix checksum */

	    return ip_output(m, NULL, NULL, IP_ENCAPSULATED | IP_RAWOUTPUT,
			     NULL, NULL);
#endif /* INET */

#ifdef INET6
	case AF_INET6:
	    ip6 = mtod(m, struct ip6_hdr *);
	    NTOHS(ip6->ip6_plen);

	    /* XXX ip6_output() has to honor those two flags... */
	    return ip6_output(m, NULL, NULL, IP_ENCAPSULATED | IP_RAWOUTPUT,
			      NULL, NULL);
#endif /* INET6 */
    }

    /* Not reached */
    return EINVAL;
}

/*
 * Lookup at the SPD based on the headers contained on the mbuf. The second
 * argument indicates what protocol family the header at the beginning of
 * the mbuf is. hlen is the the offset of the transport protocol header
 * in the mbuf.
 *
 * Return combinations (of return value and in *error):
 * - NULL/0 -> no IPsec required on packet
 * - NULL/-EINVAL -> silently drop the packet
 * - NULL/errno -> drop packet and return error
 * or a valid TDB value.
 */
struct tdb *
ipsp_spd_lookup(struct mbuf *m, int af, int hlen, int *error)
{
    struct sockaddr_encap *ddst, *gw;
    struct route_enc re0, *re = &re0;
    union sockaddr_union sunion;
    struct tdb *tdb, tdb2;

    /*
     * If there are no flows in place, there's no point
     * continuing with the SPD lookup.
     */
    if (!ipsec_in_use)
    {
	*error = 0;
	return NULL;
    }

    bzero((caddr_t) re, sizeof(*re));
    ddst = (struct sockaddr_encap *) &re->re_dst;
    ddst->sen_family = PF_KEY;

    /*
     * Do an SPD lookup -- this code should probably be moved
     * to a separate function.
     */
    switch (af)
    {
#ifdef INET
	case AF_INET:
	    ddst->sen_len = SENT_IP4_LEN;
	    ddst->sen_type = SENT_IP4;
	    m_copydata(m, offsetof(struct ip, ip_src),
		       sizeof(struct in_addr), (caddr_t) &(ddst->sen_ip_src));
	    m_copydata(m, offsetof(struct ip, ip_dst),
		       sizeof(struct in_addr), (caddr_t) &(ddst->sen_ip_dst));
	    m_copydata(m, offsetof(struct ip, ip_p), sizeof(u_int8_t),
		       (caddr_t) &(ddst->sen_proto));

	    /* If TCP/UDP, extract the port numbers to use in the lookup */
	    switch (ddst->sen_proto)
	    {
		case IPPROTO_UDP:
		case IPPROTO_TCP:
		    /*
		     * Luckily, the offset of the src/dst ports in both the UDP
		     * and TCP headers is the same (first two 16-bit values
		     * in the respective headers), so we can just copy them.
		     */
		    m_copydata(m, hlen, sizeof(u_int16_t),
			       (caddr_t) &(ddst->sen_sport));
		    m_copydata(m, hlen + sizeof(u_int16_t), sizeof(u_int16_t),
			       (caddr_t) &(ddst->sen_dport));
		    break;

		default:
		    ddst->sen_sport = 0;
		    ddst->sen_dport = 0;
	    }

	    break;
#endif /* INET */

#ifdef INET6
	case AF_INET6:
	    ddst->sen_len = SENT_IP6_LEN;
	    ddst->sen_type = SENT_IP6;
	    m_copydata(m, offsetof(struct ip6_hdr, ip6_src),
		       sizeof(struct in6_addr),
		       (caddr_t) &(ddst->sen_ip6_src));
	    m_copydata(m, offsetof(struct ip6_hdr, ip6_dst),
		       sizeof(struct in6_addr),
		       (caddr_t) &(ddst->sen_ip6_dst));
	    m_copydata(m, offsetof(struct ip6_hdr, ip6_nxt), sizeof(u_int8_t),
		       (caddr_t) &(ddst->sen_ip6_proto));

	    /* If TCP/UDP, extract the port numbers to use in the lookup */
	    switch (ddst->sen_ip6_proto)
	    {
		case IPPROTO_UDP:
		case IPPROTO_TCP:
		    /*
		     * Luckily, the offset of the src/dst ports in both the UDP
		     * and TCP headers is the same (first two 16-bit values
		     * in the respective headers), so we can just copy them.
		     */
		    m_copydata(m, hlen, sizeof(u_int16_t),
			       (caddr_t) &(ddst->sen_ip6_sport));
		    m_copydata(m, hlen + sizeof(u_int16_t), sizeof(u_int16_t),
			       (caddr_t) &(ddst->sen_ip6_dport));
		    break;

		default:
		    ddst->sen_ip6_sport = 0;
		    ddst->sen_ip6_dport = 0;
	    }

	    break;
#endif /* INET6 */

	default:
	    *error = EAFNOSUPPORT;
	    return NULL;
    }

    /* Actual SPD lookup */
    rtalloc((struct route *) re);
    if (re->re_rt == NULL)
    {
	*error = 0;
	return NULL; /* Nothing found */
    }

    bzero(&sunion, sizeof(sunion));
    gw = (struct sockaddr_encap *) (re->re_rt->rt_gateway);

    /* Sanity check */
    if (gw == NULL || ((gw->sen_type != SENT_IPSP) &&
		       (gw->sen_type != SENT_IPSP6)))
    {
	DPRINTF(("ipsp_spd_lookup(): no gw, or gw data not IPSP (%d)\n",
		 gw->sen_type));

	if (re->re_rt)
	  RTFREE(re->re_rt);
	*error = EHOSTUNREACH;
	return NULL;
    }

    /*
     * There might be a specific route, that tells us to avoid
     * doing IPsec; this is useful for specific routes that we
     * don't want to have IPsec applied on, like the key
     * management ports.
     */
    switch (gw->sen_type)
    {
#ifdef INET
	case SENT_IPSP:
	    if ((gw->sen_ipsp_sproto == 0) && (gw->sen_ipsp_spi == 0) &&
		(gw->sen_ipsp_dst.s_addr == 0))
	    {
		*error = 0;
		return NULL;
	    }

	    sunion.sin.sin_family = AF_INET;
	    sunion.sin.sin_len = sizeof(struct sockaddr_in);
	    sunion.sin.sin_addr = gw->sen_ipsp_dst;
	    break;
#endif /* INET */

#ifdef INET6
	case SENT_IPSP6:
	    if ((gw->sen_ipsp6_sproto == 0) && (gw->sen_ipsp6_spi == 0) &&
		IN6_IS_ADDR_UNSPECIFIED(&gw->sen_ipsp6_dst))
	    {
		*error = 0;
		return NULL;
	    }

	    sunion.sin6.sin6_family = AF_INET6;
	    sunion.sin6.sin6_len = sizeof(struct sockaddr_in6);
	    sunion.sin6.sin6_addr = gw->sen_ipsp6_dst;
	    break;
#endif /* INET6 */

	default:
	    *error = EAFNOSUPPORT;
	    return NULL;
    }

    /*
     * At this point we have an IPSP "gateway" (tunnel) spec.
     * Use the destination of the tunnel and the SPI to
     * look up the necessary Tunnel Control Block. Look it up,
     * and then pass it, along with the packet and the gw,
     * to the appropriate transformation.
     */
    tdb = (struct tdb *) gettdb(gw->sen_ipsp_spi, &sunion,
				gw->sen_ipsp_sproto);

    /* Bypass the SA acquisition if that is what we want. */
    if (tdb && tdb->tdb_satype == SADB_X_SATYPE_BYPASS)
    {
	*error = 0;
	return NULL;
    }

    /* 
     * For VPNs, a route with a reserved SPI is used to
     * indicate the need for an SA when none is established.
     */
    if (((ntohl(gw->sen_ipsp_spi) == SPI_LOCAL_USE) &&
	 (gw->sen_type == SENT_IPSP)) ||
	((ntohl(gw->sen_ipsp6_spi) == SPI_LOCAL_USE) &&
	 (gw->sen_type == SENT_IPSP6)))
    {
	if (tdb == NULL)
	{
	    /* We will just use system defaults. */
	    tdb = &tdb2;
	    bzero(&tdb2, sizeof(tdb2));

	    /* Default entry is for ESP */
	    tdb2.tdb_satype = SADB_SATYPE_ESP;
	}

	*error = ipsp_acquire_sa(tdb);
	if (*error == 0)
	  *error = -EINVAL; /* Silently drop the packet */
	return NULL;
    }

    /* Couldn't find the TDB */
    if (tdb == NULL)
    {
#ifdef INET
	if (gw->sen_type == SENT_IPSP)
	  DPRINTF(("ipsp_spd_lookup(): non-existant TDB for SA %s/%08x/%u\n",
		   inet_ntoa4(gw->sen_ipsp_dst), ntohl(gw->sen_ipsp_spi),
		   gw->sen_ipsp_sproto));
#endif /* INET */

#ifdef INET6
	if (gw->sen_type == SENT_IPSP6)
	  DPRINTF(("ipsp_spd_lookup(): non-existant TDB for SA %s/%08x/%u\n",
		   ip6_sprintf(gw->sen_ipsp6_dst), ntohl(gw->sen_ipsp6_spi),
		   gw->sen_ipsp6_sproto));
#endif /* INET6 */	  

	*error = EHOSTUNREACH;
	return NULL;
    }

    /* Done, IPsec processing necessary */
    *error = 0;
    return tdb;
}

/*
 * Use PFKEY to acquire an SA.
 */
int
ipsp_acquire_sa(struct tdb *tdb)
{
    /* Check whether Perfect Forward Secrect is required */
    if (ipsec_require_pfs)
      tdb->tdb_flags |= TDBF_PFS;
    else
      tdb->tdb_flags &= ~TDBF_PFS;

    /* Initialize expirations */
    if (ipsec_soft_allocations > 0) 
      tdb->tdb_soft_allocations = ipsec_soft_allocations;
    else
      tdb->tdb_soft_allocations = 0;

    if (ipsec_exp_allocations > 0)
      tdb->tdb_exp_allocations = ipsec_exp_allocations;
    else
      tdb->tdb_exp_allocations = 0;

    if (ipsec_soft_bytes > 0)
      tdb->tdb_soft_bytes = ipsec_soft_bytes;
    else
      tdb->tdb_soft_bytes = 0;

    if (ipsec_exp_bytes > 0)
      tdb->tdb_exp_bytes = ipsec_exp_bytes;
    else
      tdb->tdb_exp_bytes = 0;

    if (ipsec_soft_timeout > 0)
      tdb->tdb_soft_timeout = ipsec_soft_timeout;
    else
      tdb->tdb_soft_timeout = 0;

    if (ipsec_exp_timeout > 0)
      tdb->tdb_exp_timeout = ipsec_exp_timeout;
    else
      tdb->tdb_exp_timeout = 0;

    if (ipsec_soft_first_use > 0)
      tdb->tdb_soft_first_use = ipsec_soft_first_use;
    else
      tdb->tdb_soft_first_use = 0;

    if (ipsec_exp_first_use > 0)
      tdb->tdb_exp_first_use = ipsec_exp_first_use;
    else
      tdb->tdb_exp_first_use = 0;

    /* 
     * If we don't have an existing desired encryption
     * algorithm, use the default.
     */
    if ((tdb->tdb_encalgxform == NULL) &&
	(tdb->tdb_satype & NOTIFY_SATYPE_CONF))
    {
	if (!strncasecmp(ipsec_def_enc, "des", sizeof("des")))
	  tdb->tdb_encalgxform = &enc_xform_des;
	else
	  if (!strncasecmp(ipsec_def_enc, "3des",
			   sizeof("3des")))
	    tdb->tdb_encalgxform = &enc_xform_3des;
	  else
	    if (!strncasecmp(ipsec_def_enc, "blowfish",
			     sizeof("blowfish")))
	      tdb->tdb_encalgxform = &enc_xform_blf;
	    else
	      if (!strncasecmp(ipsec_def_enc, "cast128",
			       sizeof("cast128")))
		tdb->tdb_encalgxform = &enc_xform_cast5;
	      else
		if (!strncasecmp(ipsec_def_enc, "skipjack",
				 sizeof("skipjack")))
		  tdb->tdb_encalgxform = &enc_xform_skipjack;
    }

    /*
     * If we don't have an existing desired authentication
     * algorithm, use the default.
     */
    if ((tdb->tdb_authalgxform == NULL) && 
	(tdb->tdb_satype & NOTIFY_SATYPE_AUTH))
    {
	if (!strncasecmp(ipsec_def_auth, "hmac-md5",
			 sizeof("hmac-md5")))
	  tdb->tdb_authalgxform = &auth_hash_hmac_md5_96;
	else
	  if (!strncasecmp(ipsec_def_auth, "hmac-sha1",
			   sizeof("hmac-sha1")))
	    tdb->tdb_authalgxform = &auth_hash_hmac_sha1_96;
	  else
	    if (!strncasecmp(ipsec_def_auth, "hmac-ripemd160",
			     sizeof("hmac_ripemd160")))
	      tdb->tdb_authalgxform = &auth_hash_hmac_ripemd_160_96;
    }

    /* XXX Initialize src_id/dst_id */

    /* PF_KEYv2 notification message */
    return pfkeyv2_acquire(tdb, 0);
}