bind.c

/* bind.c - ldap backend bind function */
/* $OpenLDAP$ */
/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
 *
 * Copyright 1999-2007 The OpenLDAP Foundation.
 * Portions Copyright 2000-2003 Pierangelo Masarati.
 * Portions Copyright 1999-2003 Howard Chu.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted only as authorized by the OpenLDAP
 * Public License.
 *
 * A copy of this license is available in the file LICENSE in the
 * top-level directory of the distribution or, alternatively, at
 * <http://www.OpenLDAP.org/license.html>.
 */
/* ACKNOWLEDGEMENTS:
 * This work was initially developed by Howard Chu for inclusion
 * in OpenLDAP Software and subsequently enhanced by Pierangelo
 * Masarati.
 */

#include "portable.h"

#include <stdio.h>

#include <ac/errno.h>
#include <ac/socket.h>
#include <ac/string.h>

#define AVL_INTERNAL
#include "slap.h"
#include "back-ldap.h"
#undef ldap_debug	/* silence a warning in ldap-int.h */
#include "../../../libraries/libldap/ldap-int.h"

#include "lutil_ldap.h"

#define LDAP_CONTROL_OBSOLETE_PROXY_AUTHZ	"2.16.840.1.113730.3.4.12"

#if LDAP_BACK_PRINT_CONNTREE > 0
static void
ldap_back_ravl_print( Avlnode *root, int depth )
{
	int		i;
	ldapconn_t	*lc;
	
	if ( root == 0 ) {
		return;
	}
	
	ldap_back_ravl_print( root->avl_right, depth+1 );
	
	for ( i = 0; i < depth; i++ ) {
		fprintf( stderr, "-" );
	}

	lc = root->avl_data;
	fprintf( stderr, "lc=%p local=\"%s\" conn=%p %s refcnt=%d flags=0x%08x\n",
		(void *)lc,
		lc->lc_local_ndn.bv_val ? lc->lc_local_ndn.bv_val : "",
		(void *)lc->lc_conn,
		avl_bf2str( root->avl_bf ), lc->lc_refcnt, lc->lc_lcflags );
	
	ldap_back_ravl_print( root->avl_left, depth+1 );
}

static char* priv2str[] = {
	"privileged",
	"privileged/TLS",
	"anonymous",
	"anonymous/TLS",
	"bind",
	"bind/TLS",
	NULL
};

void
ldap_back_print_conntree( ldapinfo_t *li, char *msg )
{
	int	c;

	fprintf( stderr, "========> %s\n", msg );

	for ( c = LDAP_BACK_PCONN_FIRST; c < LDAP_BACK_PCONN_LAST; c++ ) {
		int		i = 0;
		ldapconn_t	*lc;

		fprintf( stderr, "  %s[%d]\n", priv2str[ c ], li->li_conn_priv[ c ].lic_num );

		LDAP_TAILQ_FOREACH( lc, &li->li_conn_priv[ c ].lic_priv, lc_q )
		{
			fprintf( stderr, "    [%d] lc=%p local=\"%s\" conn=%p refcnt=%d flags=0x%08x\n",
				i,
				(void *)lc,
				lc->lc_local_ndn.bv_val ? lc->lc_local_ndn.bv_val : "",
				(void *)lc->lc_conn, lc->lc_refcnt, lc->lc_lcflags );
			i++;
		}
	}
	
	if ( li->li_conninfo.lai_tree == 0 ) {
		fprintf( stderr, "\t(empty)\n" );

	} else {
		ldap_back_ravl_print( li->li_conninfo.lai_tree, 0 );
	}
	
	fprintf( stderr, "<======== %s\n", msg );
}
#endif /* LDAP_BACK_PRINT_CONNTREE */

static int
ldap_back_freeconn( ldapinfo_t *li, ldapconn_t *lc, int dolock );

static ldapconn_t *
ldap_back_getconn( Operation *op, SlapReply *rs, ldap_back_send_t sendok,
	struct berval *binddn, struct berval *bindcred );

static int
ldap_back_is_proxy_authz( Operation *op, SlapReply *rs, ldap_back_send_t sendok,
	struct berval *binddn, struct berval *bindcred );

static int
ldap_back_proxy_authz_bind( ldapconn_t *lc, Operation *op, SlapReply *rs,
	ldap_back_send_t sendok, struct berval *binddn, struct berval *bindcred );

static int
ldap_back_prepare_conn( ldapconn_t *lc, Operation *op, SlapReply *rs,
	ldap_back_send_t sendok );

static int
ldap_back_conndnlc_cmp( const void *c1, const void *c2 );

ldapconn_t *
ldap_back_conn_delete( ldapinfo_t *li, ldapconn_t *lc )
{
	if ( LDAP_BACK_PCONN_ISPRIV( lc ) ) {
		if ( LDAP_BACK_CONN_CACHED( lc ) ) {
			assert( lc->lc_q.tqe_prev != NULL );
			assert( li->li_conn_priv[ LDAP_BACK_CONN2PRIV( lc ) ].lic_num > 0 );
			li->li_conn_priv[ LDAP_BACK_CONN2PRIV( lc ) ].lic_num--;
			LDAP_TAILQ_REMOVE( &li->li_conn_priv[ LDAP_BACK_CONN2PRIV( lc ) ].lic_priv, lc, lc_q );
			LDAP_TAILQ_ENTRY_INIT( lc, lc_q );
			LDAP_BACK_CONN_CACHED_CLEAR( lc );

		} else {
			assert( LDAP_BACK_CONN_TAINTED( lc ) );
			assert( lc->lc_q.tqe_prev == NULL );
		}

	} else {
		ldapconn_t	*tmplc = NULL;

		if ( LDAP_BACK_CONN_CACHED( lc ) ) {
			assert( !LDAP_BACK_CONN_TAINTED( lc ) );
			tmplc = avl_delete( &li->li_conninfo.lai_tree, (caddr_t)lc,
				ldap_back_conndnlc_cmp );
			assert( tmplc == lc );
			LDAP_BACK_CONN_CACHED_CLEAR( lc );
		}

		assert( LDAP_BACK_CONN_TAINTED( lc ) || tmplc == lc );
	}

	return lc;
}

int
ldap_back_bind( Operation *op, SlapReply *rs )
{
	ldapinfo_t		*li = (ldapinfo_t *) op->o_bd->be_private;
	ldapconn_t		*lc;

	int			rc = 0;
	ber_int_t		msgid;
	ldap_back_send_t	retrying = LDAP_BACK_RETRYING;

	lc = ldap_back_getconn( op, rs, LDAP_BACK_BIND_SERR, NULL, NULL );
	if ( !lc ) {
		return rs->sr_err;
	}

	/* we can do (almost) whatever we want with this conn,
	 * because either it's temporary, or it's marked as binding */
	if ( !BER_BVISNULL( &lc->lc_bound_ndn ) ) {
		ch_free( lc->lc_bound_ndn.bv_val );
		BER_BVZERO( &lc->lc_bound_ndn );
	}
	if ( !BER_BVISNULL( &lc->lc_cred ) ) {
		memset( lc->lc_cred.bv_val, 0, lc->lc_cred.bv_len );
		ch_free( lc->lc_cred.bv_val );
		BER_BVZERO( &lc->lc_cred );
	}
	LDAP_BACK_CONN_ISBOUND_CLEAR( lc );

retry:;
	/* method is always LDAP_AUTH_SIMPLE if we got here */
	rs->sr_err = ldap_sasl_bind( lc->lc_ld, op->o_req_dn.bv_val,
			LDAP_SASL_SIMPLE,
			&op->orb_cred, op->o_ctrls, NULL, &msgid );
	/* FIXME: should we always retry, or only when piping the bind
	 * in the "override" connection pool? */
	rc = ldap_back_op_result( lc, op, rs, msgid,
		li->li_timeout[ SLAP_OP_BIND ],
		LDAP_BACK_BIND_SERR | retrying );
	if ( rc == LDAP_UNAVAILABLE && retrying ) {
		retrying &= ~LDAP_BACK_RETRYING;
		if ( ldap_back_retry( &lc, op, rs, LDAP_BACK_BIND_SERR ) ) {
			goto retry;
		}
	}

	if ( rc == LDAP_SUCCESS ) {
		/* If defined, proxyAuthz will be used also when
		 * back-ldap is the authorizing backend; for this
		 * purpose, after a successful bind the connection
		 * is left for further binds, and further operations 
		 * on this client connection will use a default
		 * connection with identity assertion */
		/* NOTE: use with care */
		if ( li->li_idassert_flags & LDAP_BACK_AUTH_OVERRIDE ) {
			ldap_back_release_conn( li, lc );
			return( rc );
		}

		/* rebind is now done inside ldap_back_proxy_authz_bind()
		 * in case of success */
		LDAP_BACK_CONN_ISBOUND_SET( lc );
		ber_dupbv( &lc->lc_bound_ndn, &op->o_req_ndn );

		if ( !BER_BVISNULL( &lc->lc_cred ) ) {
			memset( lc->lc_cred.bv_val, 0,
					lc->lc_cred.bv_len );
		}

		if ( LDAP_BACK_SAVECRED( li ) ) {
			ber_bvreplace( &lc->lc_cred, &op->orb_cred );
			ldap_set_rebind_proc( lc->lc_ld, li->li_rebind_f, lc );

		} else {
			lc->lc_cred.bv_len = 0;
		}
	}

	/* must re-insert if local DN changed as result of bind */
	if ( !LDAP_BACK_CONN_ISBOUND( lc )
		|| ( !dn_match( &op->o_req_ndn, &lc->lc_local_ndn )
			&& !LDAP_BACK_PCONN_ISPRIV( lc ) ) )
	{
		int		lerr = -1;
		ldapconn_t	*tmplc;

		/* wait for all other ops to release the connection */
retry_lock:;
		ldap_pvt_thread_mutex_lock( &li->li_conninfo.lai_mutex );
		if ( lc->lc_refcnt > 1 ) {
			ldap_pvt_thread_mutex_unlock( &li->li_conninfo.lai_mutex );
			ldap_pvt_thread_yield();
			goto retry_lock;
		}

#if LDAP_BACK_PRINT_CONNTREE > 0
		ldap_back_print_conntree( li, ">>> ldap_back_bind" );
#endif /* LDAP_BACK_PRINT_CONNTREE */

		assert( lc->lc_refcnt == 1 );
		ldap_back_conn_delete( li, lc );

		/* delete all cached connections with the current connection */
		if ( LDAP_BACK_SINGLECONN( li ) ) {
			while ( ( tmplc = avl_delete( &li->li_conninfo.lai_tree, (caddr_t)lc, ldap_back_conn_cmp ) ) != NULL )
			{
				Debug( LDAP_DEBUG_TRACE,
					"=>ldap_back_bind: destroying conn %ld (refcnt=%u)\n",
					LDAP_BACK_PCONN_ID( lc ), lc->lc_refcnt, 0 );

				if ( tmplc->lc_refcnt != 0 ) {
					/* taint it */
					LDAP_BACK_CONN_TAINTED_SET( tmplc );
					LDAP_BACK_CONN_CACHED_CLEAR( tmplc );

				} else {
					/*
					 * Needs a test because the handler may be corrupted,
					 * and calling ldap_unbind on a corrupted header results
					 * in a segmentation fault
					 */
					ldap_back_conn_free( tmplc );
				}
			}
		}

		if ( LDAP_BACK_CONN_ISBOUND( lc ) ) {
			ber_bvreplace( &lc->lc_local_ndn, &op->o_req_ndn );
			if ( be_isroot_dn( op->o_bd, &op->o_req_ndn ) ) {
				LDAP_BACK_PCONN_ROOTDN_SET( lc, op );
			}
			lerr = avl_insert( &li->li_conninfo.lai_tree, (caddr_t)lc,
				ldap_back_conndn_cmp, ldap_back_conndn_dup );
		}

#if LDAP_BACK_PRINT_CONNTREE > 0
		ldap_back_print_conntree( li, "<<< ldap_back_bind" );
#endif /* LDAP_BACK_PRINT_CONNTREE */
	
		ldap_pvt_thread_mutex_unlock( &li->li_conninfo.lai_mutex );
		switch ( lerr ) {
		case 0:
			LDAP_BACK_CONN_CACHED_SET( lc );
			break;

		case -1:
			/* duplicate; someone else successfully bound
			 * on the same connection with the same identity;
			 * we can do this because lc_refcnt == 1 */
			ldap_back_conn_free( lc );
			lc = NULL;
		}
	}

	if ( lc != NULL ) {
		ldap_back_release_conn( li, lc );
	}

	return( rc );
}

/*
 * ldap_back_conndn_cmp
 *
 * compares two ldapconn_t based on the value of the conn pointer
 * and of the local DN; used by avl stuff for insert, lookup
 * and direct delete
 */
int
ldap_back_conndn_cmp( const void *c1, const void *c2 )
{
	const ldapconn_t	*lc1 = (const ldapconn_t *)c1;
	const ldapconn_t	*lc2 = (const ldapconn_t *)c2;
	int rc;

	/* If local DNs don't match, it is definitely not a match */
	/* For shared sessions, conn is NULL. Only explicitly
	 * bound sessions will have non-NULL conn.
	 */
	rc = SLAP_PTRCMP( lc1->lc_conn, lc2->lc_conn );
	if ( rc == 0 ) {
		rc = ber_bvcmp( &lc1->lc_local_ndn, &lc2->lc_local_ndn );
	}

	return rc;
}

/*
 * ldap_back_conndnlc_cmp
 *
 * compares two ldapconn_t based on the value of the conn pointer,
 * the local DN and the lc pointer; used by avl stuff for insert, lookup
 * and direct delete
 */
static int
ldap_back_conndnlc_cmp( const void *c1, const void *c2 )
{
	const ldapconn_t	*lc1 = (const ldapconn_t *)c1;
	const ldapconn_t	*lc2 = (const ldapconn_t *)c2;
	int rc;

	/* If local DNs don't match, it is definitely not a match */
	/* For shared sessions, conn is NULL. Only explicitly
	 * bound sessions will have non-NULL conn.
	 */
	rc = SLAP_PTRCMP( lc1->lc_conn, lc2->lc_conn );
	if ( rc == 0 ) {
		rc = ber_bvcmp( &lc1->lc_local_ndn, &lc2->lc_local_ndn );
		if ( rc == 0 ) {
			rc = SLAP_PTRCMP( lc1, lc2 );
		}
	}

	return rc;
}

/*
 * ldap_back_conn_cmp
 *
 * compares two ldapconn_t based on the value of the conn pointer;
 * used by avl stuff for delete of all conns with the same connid
 */
int
ldap_back_conn_cmp( const void *c1, const void *c2 )
{
	const ldapconn_t	*lc1 = (const ldapconn_t *)c1;
	const ldapconn_t	*lc2 = (const ldapconn_t *)c2;

	/* For shared sessions, conn is NULL. Only explicitly
	 * bound sessions will have non-NULL conn.
	 */
	return SLAP_PTRCMP( lc1->lc_conn, lc2->lc_conn );
}

/*
 * ldap_back_conndn_dup
 *
 * returns -1 in case a duplicate ldapconn_t has been inserted;
 * used by avl stuff
 */
int
ldap_back_conndn_dup( void *c1, void *c2 )
{
	ldapconn_t	*lc1 = (ldapconn_t *)c1;
	ldapconn_t	*lc2 = (ldapconn_t *)c2;

	/* Cannot have more than one shared session with same DN */
	if ( lc1->lc_conn == lc2->lc_conn &&
		dn_match( &lc1->lc_local_ndn, &lc2->lc_local_ndn ) )
	{
		return -1;
	}
		
	return 0;
}

static int
ldap_back_freeconn( ldapinfo_t *li, ldapconn_t *lc, int dolock )
{
	if ( dolock ) {
		ldap_pvt_thread_mutex_lock( &li->li_conninfo.lai_mutex );
	}

#if LDAP_BACK_PRINT_CONNTREE > 0
	ldap_back_print_conntree( li, ">>> ldap_back_freeconn" );
#endif /* LDAP_BACK_PRINT_CONNTREE */

	(void)ldap_back_conn_delete( li, lc );

	if ( lc->lc_refcnt == 0 ) {
		ldap_back_conn_free( (void *)lc );
	}

#if LDAP_BACK_PRINT_CONNTREE > 0
	ldap_back_print_conntree( li, "<<< ldap_back_freeconn" );
#endif /* LDAP_BACK_PRINT_CONNTREE */

	if ( dolock ) {
		ldap_pvt_thread_mutex_unlock( &li->li_conninfo.lai_mutex );
	}

	return 0;
}

#ifdef HAVE_TLS
static int
ldap_back_start_tls(
	LDAP		*ld,
	int		protocol,
	int		*is_tls,
	const char	*url,
	unsigned	flags,
	int		retries,
	const char	**text )
{
	int		rc = LDAP_SUCCESS;

	/* start TLS ("tls-[try-]{start,propagate}" statements) */
	if ( ( LDAP_BACK_USE_TLS_F( flags ) || ( *is_tls && LDAP_BACK_PROPAGATE_TLS_F( flags ) ) )
				&& !ldap_is_ldaps_url( url ) )
	{
#ifdef SLAP_STARTTLS_ASYNCHRONOUS
		/*
		 * use asynchronous StartTLS
		 * in case, chase referral (not implemented yet)
		 */
		int		msgid;

		if ( protocol == 0 ) {
			ldap_get_option( ld, LDAP_OPT_PROTOCOL_VERSION,
					(void *)&protocol );
		}

		if ( protocol < LDAP_VERSION3 ) {
			/* we should rather bail out... */
			rc = LDAP_UNWILLING_TO_PERFORM;
			*text = "invalid protocol version";
		}

		if ( rc == LDAP_SUCCESS ) {
			rc = ldap_start_tls( ld, NULL, NULL, &msgid );
		}

		if ( rc == LDAP_SUCCESS ) {
			LDAPMessage	*res = NULL;
			struct timeval	tv;

			LDAP_BACK_TV_SET( &tv );

retry:;
			rc = ldap_result( ld, msgid, LDAP_MSG_ALL, &tv, &res );
			if ( rc < 0 ) {
				rc = LDAP_UNAVAILABLE;

			} else if ( rc == 0 ) {
				if ( retries != LDAP_BACK_RETRY_NEVER ) {
					ldap_pvt_thread_yield();
					if ( retries > 0 ) {
						retries--;
					}
					LDAP_BACK_TV_SET( &tv );
					goto retry;
				}
				rc = LDAP_UNAVAILABLE;

			} else if ( rc == LDAP_RES_EXTENDED ) {
				struct berval	*data = NULL;

				rc = ldap_parse_extended_result( ld, res,
						NULL, &data, 0 );
				if ( rc == LDAP_SUCCESS ) {
					int err;
					rc = ldap_parse_result( ld, res, &err,
						NULL, NULL, NULL, NULL, 1 );
					if ( rc == LDAP_SUCCESS ) {
						rc = err;
					}
					res = NULL;
					
					/* FIXME: in case a referral 
					 * is returned, should we try
					 * using it instead of the 
					 * configured URI? */
					if ( rc == LDAP_SUCCESS ) {
						rc = ldap_install_tls( ld );

					} else if ( rc == LDAP_REFERRAL ) {
						rc = LDAP_UNWILLING_TO_PERFORM;
						*text = "unwilling to chase referral returned by Start TLS exop";
					}

					if ( data ) {
						if ( data->bv_val ) {
							ber_memfree( data->bv_val );
						}
						ber_memfree( data );
					}
				}

			} else {
				rc = LDAP_OTHER;
			}

			if ( res != NULL ) {
				ldap_msgfree( res );
			}
		}
#else /* ! SLAP_STARTTLS_ASYNCHRONOUS */
		/*
		 * use synchronous StartTLS
		 */
		rc = ldap_start_tls_s( ld, NULL, NULL );
#endif /* ! SLAP_STARTTLS_ASYNCHRONOUS */

		/* if StartTLS is requested, only attempt it if the URL
		 * is not "ldaps://"; this may occur not only in case
		 * of misconfiguration, but also when used in the chain 
		 * overlay, where the "uri" can be parsed out of a referral */
		switch ( rc ) {
		case LDAP_SUCCESS:
			*is_tls = 1;
			break;

		case LDAP_SERVER_DOWN:
			break;

		default:
			if ( LDAP_BACK_TLS_CRITICAL_F( flags ) ) {
				*text = "could not start TLS";
				break;
			}

			/* in case Start TLS is not critical */
			*is_tls = 0;
			rc = LDAP_SUCCESS;
			break;
		}

	} else {
		*is_tls = 0;
	}

	return rc;
}
#endif /* HAVE_TLS */

static int
ldap_back_prepare_conn( ldapconn_t *lc, Operation *op, SlapReply *rs, ldap_back_send_t sendok )
{
	ldapinfo_t	*li = (ldapinfo_t *)op->o_bd->be_private;
	int		version;
	LDAP		*ld = NULL;
#ifdef HAVE_TLS
	int		is_tls = op->o_conn->c_is_tls;
	time_t		lc_time = (time_t)(-1);
#endif /* HAVE_TLS */

	ldap_pvt_thread_mutex_lock( &li->li_uri_mutex );
	rs->sr_err = ldap_initialize( &ld, li->li_uri );
	ldap_pvt_thread_mutex_unlock( &li->li_uri_mutex );
	if ( rs->sr_err != LDAP_SUCCESS ) {
		goto error_return;
	}

	/* Set LDAP version. This will always succeed: If the client
	 * bound with a particular version, then so can we.
	 */
	if ( li->li_version != 0 ) {
		version = li->li_version;

	} else if ( op->o_protocol != 0 ) {
		version = op->o_protocol;

	} else {
		/* assume it's an internal op; set to LDAPv3 */
		version = LDAP_VERSION3;
	}
	ldap_set_option( ld, LDAP_OPT_PROTOCOL_VERSION, (const void *)&version );

	/* automatically chase referrals ("chase-referrals [{yes|no}]" statement) */
	ldap_set_option( ld, LDAP_OPT_REFERRALS,
		LDAP_BACK_CHASE_REFERRALS( li ) ? LDAP_OPT_ON : LDAP_OPT_OFF );

	if ( li->li_network_timeout > 0 ) {
		struct timeval		tv;

		tv.tv_sec = li->li_network_timeout;
		tv.tv_usec = 0;
		ldap_set_option( ld, LDAP_OPT_NETWORK_TIMEOUT, (const void *)&tv );
	}

#ifdef HAVE_TLS
	ldap_pvt_thread_mutex_lock( &li->li_uri_mutex );
	rs->sr_err = ldap_back_start_tls( ld, op->o_protocol, &is_tls,
			li->li_uri, li->li_flags, li->li_nretries, &rs->sr_text );
	ldap_pvt_thread_mutex_unlock( &li->li_uri_mutex );
	if ( rs->sr_err != LDAP_SUCCESS ) {
		ldap_unbind_ext( ld, NULL, NULL );
		rs->sr_text = "Start TLS failed";
		goto error_return;

	} else if ( li->li_idle_timeout ) {
		/* only touch when activity actually took place... */
		lc_time = op->o_time;
	}
#endif /* HAVE_TLS */

	lc->lc_ld = ld;
	lc->lc_refcnt = 1;
#ifdef HAVE_TLS
	if ( is_tls ) {
		LDAP_BACK_CONN_ISTLS_SET( lc );
	} else {
		LDAP_BACK_CONN_ISTLS_CLEAR( lc );
	}
	if ( lc_time != (time_t)(-1) ) {
		lc->lc_time = lc_time;
	}
#endif /* HAVE_TLS */

error_return:;
	if ( rs->sr_err != LDAP_SUCCESS ) {
		rs->sr_err = slap_map_api2result( rs );
		if ( sendok & LDAP_BACK_SENDERR ) {
			if ( rs->sr_text == NULL ) {
				rs->sr_text = "Proxy connection initialization failed";
			}
			send_ldap_result( op, rs );
		}

	} else {
		if ( li->li_conn_ttl > 0 ) {
			lc->lc_create_time = op->o_time;
		}
	}

	return rs->sr_err;
}

static ldapconn_t *
ldap_back_getconn(
	Operation		*op,
	SlapReply		*rs,
	ldap_back_send_t	sendok,
	struct berval		*binddn,
	struct berval		*bindcred )
{
	ldapinfo_t	*li = (ldapinfo_t *)op->o_bd->be_private;
	ldapconn_t	*lc = NULL,
			lc_curr = { 0 };
	int		refcnt = 1,
			lookupconn = !( sendok & LDAP_BACK_BINDING );

	/* if the server is quarantined, and
	 * - the current interval did not expire yet, or
	 * - no more retries should occur,
	 * don't return the connection */
	if ( li->li_isquarantined ) {
		slap_retry_info_t	*ri = &li->li_quarantine;
		int			dont_retry = 1;

		if ( li->li_quarantine.ri_interval ) {
			ldap_pvt_thread_mutex_lock( &li->li_quarantine_mutex );
			if ( li->li_isquarantined == LDAP_BACK_FQ_YES ) {
				dont_retry = ( ri->ri_num[ ri->ri_idx ] == SLAP_RETRYNUM_TAIL
					|| slap_get_time() < ri->ri_last + ri->ri_interval[ ri->ri_idx ] );
				if ( !dont_retry ) {
					Debug( LDAP_DEBUG_ANY,
						"%s: ldap_back_getconn quarantine "
						"retry block #%d try #%d.\n",
						op->o_log_prefix, ri->ri_idx, ri->ri_count );
					li->li_isquarantined = LDAP_BACK_FQ_RETRYING;
				}
			}
			ldap_pvt_thread_mutex_unlock( &li->li_quarantine_mutex );
		}

		if ( dont_retry ) {
			rs->sr_err = LDAP_UNAVAILABLE;
			if ( op->o_conn && ( sendok & LDAP_BACK_SENDERR ) ) {
				rs->sr_text = "Target is quarantined";
				send_ldap_result( op, rs );
			}
			return NULL;
		}
	}

	/* Internal searches are privileged and shared. So is root. */
	if ( op->o_do_not_cache || be_isroot( op ) ) {
		LDAP_BACK_CONN_ISPRIV_SET( &lc_curr );
		lc_curr.lc_local_ndn = op->o_bd->be_rootndn;
		LDAP_BACK_PCONN_ROOTDN_SET( &lc_curr, op );

	} else {
		struct berval	tmpbinddn,
				tmpbindcred,
				save_o_dn,
				save_o_ndn;
		int		isproxyauthz;

		/* need cleanup */
		if ( binddn == NULL ) {
			binddn = &tmpbinddn;
		}	
		if ( bindcred == NULL ) {
			bindcred = &tmpbindcred;
		}
		if ( op->o_tag == LDAP_REQ_BIND ) {
			save_o_dn = op->o_dn;
			save_o_ndn = op->o_ndn;
			op->o_dn = op->o_req_dn;
			op->o_ndn = op->o_req_ndn;
		}
		isproxyauthz = ldap_back_is_proxy_authz( op, rs, sendok, binddn, bindcred );
		if ( op->o_tag == LDAP_REQ_BIND ) {
			op->o_dn = save_o_dn;
			op->o_ndn = save_o_ndn;
		}
		if ( isproxyauthz == -1 ) {
			return NULL;
		}

		lc_curr.lc_local_ndn = op->o_ndn;
		/* Explicit binds must not be shared;
		 * however, explicit binds are piped in a special connection
		 * when idassert is to occur with "override" set */
		if ( op->o_tag == LDAP_REQ_BIND && !isproxyauthz ) {
			lc_curr.lc_conn = op->o_conn;

		} else {
			if ( isproxyauthz && !( sendok & LDAP_BACK_BINDING ) ) {
				lc_curr.lc_local_ndn = *binddn;
				LDAP_BACK_PCONN_ROOTDN_SET( &lc_curr, op );
				LDAP_BACK_CONN_ISIDASSERT_SET( &lc_curr );

			} else if ( isproxyauthz && ( li->li_idassert_flags & LDAP_BACK_AUTH_OVERRIDE ) ) {
				lc_curr.lc_local_ndn = slap_empty_bv;
				LDAP_BACK_PCONN_BIND_SET( &lc_curr, op );
				LDAP_BACK_CONN_ISIDASSERT_SET( &lc_curr );
				lookupconn = 1;

			} else if ( SLAP_IS_AUTHZ_BACKEND( op ) ) {
				lc_curr.lc_conn = op->o_conn;

			} else {
				LDAP_BACK_PCONN_ANON_SET( &lc_curr, op );
			}
		}
	}

	/* Explicit Bind requests always get their own conn */
	if ( lookupconn ) {
retry_lock:
		ldap_pvt_thread_mutex_lock( &li->li_conninfo.lai_mutex );
		if ( LDAP_BACK_PCONN_ISPRIV( &lc_curr ) ) {
			/* lookup a conn that's not binding */
			LDAP_TAILQ_FOREACH( lc,
				&li->li_conn_priv[ LDAP_BACK_CONN2PRIV( &lc_curr ) ].lic_priv,
				lc_q )
			{
				if ( !LDAP_BACK_CONN_BINDING( lc ) && lc->lc_refcnt == 0 ) {
					break;
				}
			}

			if ( lc != NULL ) {
				if ( lc != LDAP_TAILQ_LAST( &li->li_conn_priv[ LDAP_BACK_CONN2PRIV( lc ) ].lic_priv,
					ldapconn_t, lc_q ) )
				{
					LDAP_TAILQ_REMOVE( &li->li_conn_priv[ LDAP_BACK_CONN2PRIV( lc ) ].lic_priv,
						lc, lc_q );
					LDAP_TAILQ_ENTRY_INIT( lc, lc_q );
					LDAP_TAILQ_INSERT_TAIL( &li->li_conn_priv[ LDAP_BACK_CONN2PRIV( lc ) ].lic_priv,
						lc, lc_q );
				}

			} else if ( !LDAP_BACK_USE_TEMPORARIES( li )
				&& li->li_conn_priv[ LDAP_BACK_CONN2PRIV( &lc_curr ) ].lic_num == li->li_conn_priv_max )
			{
				lc = LDAP_TAILQ_FIRST( &li->li_conn_priv[ LDAP_BACK_CONN2PRIV( &lc_curr ) ].lic_priv );
			}
			
		} else {

			/* Searches for a ldapconn in the avl tree */
			lc = (ldapconn_t *)avl_find( li->li_conninfo.lai_tree, 
					(caddr_t)&lc_curr, ldap_back_conndn_cmp );
		}

		if ( lc != NULL ) {
			/* Don't reuse connections while they're still binding */
			if ( LDAP_BACK_CONN_BINDING( lc ) ) {
				if ( !LDAP_BACK_USE_TEMPORARIES( li ) ) {
					ldap_pvt_thread_mutex_unlock( &li->li_conninfo.lai_mutex );

					ldap_pvt_thread_yield();
					goto retry_lock;
				}
				lc = NULL;
			}

			if ( lc != NULL ) {
				if ( op->o_tag == LDAP_REQ_BIND ) {
					/* right now, this is the only possible case */
					assert( ( li->li_idassert_flags & LDAP_BACK_AUTH_OVERRIDE ) );
					LDAP_BACK_CONN_BINDING_SET( lc );
				}

				refcnt = ++lc->lc_refcnt;
			}
		}
		ldap_pvt_thread_mutex_unlock( &li->li_conninfo.lai_mutex );
	}

	/* Looks like we didn't get a bind. Open a new session... */
	if ( lc == NULL ) {
		lc = (ldapconn_t *)ch_calloc( 1, sizeof( ldapconn_t ) );
		lc->lc_flags = li->li_flags;
		lc->lc_lcflags = lc_curr.lc_lcflags;
		if ( ldap_back_prepare_conn( lc, op, rs, sendok ) != LDAP_SUCCESS ) {
			ch_free( lc );
			return NULL;
		}

		if ( sendok & LDAP_BACK_BINDING ) {
			LDAP_BACK_CONN_BINDING_SET( lc );
		}

		lc->lc_conn = lc_curr.lc_conn;
		ber_dupbv( &lc->lc_local_ndn, &lc_curr.lc_local_ndn );

		/*
		 * the rationale is: connections as the rootdn are privileged,
		 * so acl_authcDN is to be used; however, in some cases
		 * one already configured identity assertion with a highly
		 * privileged idassert_authcDN, so if acl_authcDN is NULL
		 * and idassert_authcDN is not, use the second instead.
		 *
		 * might change in the future, because it's preferable
		 * to make clear what identity is being used, since
		 * the only drawback is that one risks to configure
		 * the same identity twice...
		 */
		if ( LDAP_BACK_CONN_ISPRIV( &lc_curr ) ) {
			if ( BER_BVISNULL( &li->li_acl_authcDN ) && !BER_BVISNULL( &li->li_idassert_authcDN ) ) {
				ber_dupbv( &lc->lc_bound_ndn, &li->li_idassert_authcDN );
				ber_dupbv( &lc->lc_cred, &li->li_idassert_passwd );

			} else {
				ber_dupbv( &lc->lc_bound_ndn, &li->li_acl_authcDN );
				ber_dupbv( &lc->lc_cred, &li->li_acl_passwd );
			}
			LDAP_BACK_CONN_ISPRIV_SET( lc );

		} else if ( LDAP_BACK_CONN_ISIDASSERT( &lc_curr ) ) {
			if ( !LDAP_BACK_PCONN_ISBIND( &lc_curr ) ) {
				ber_dupbv( &lc->lc_bound_ndn, &li->li_idassert_authcDN );
				ber_dupbv( &lc->lc_cred, &li->li_idassert_passwd );
			}
			LDAP_BACK_CONN_ISIDASSERT_SET( lc );

		} else {
			BER_BVZERO( &lc->lc_cred );
			BER_BVZERO( &lc->lc_bound_ndn );
			if ( !BER_BVISEMPTY( &op->o_ndn )
				&& SLAP_IS_AUTHZ_BACKEND( op ) )
			{
				ber_dupbv( &lc->lc_bound_ndn, &op->o_ndn );
			}
		}

#ifdef HAVE_TLS
		/* if start TLS failed but it was not mandatory,
		 * check if the non-TLS connection was already
		 * in cache; in case, destroy the newly created
		 * connection and use the existing one */
		if ( LDAP_BACK_PCONN_ISTLS( lc ) 
				&& !ldap_tls_inplace( lc->lc_ld ) )
		{
			ldapconn_t	*tmplc = NULL;
			int		idx = LDAP_BACK_CONN2PRIV( &lc_curr ) - 1;
			
			ldap_pvt_thread_mutex_lock( &li->li_conninfo.lai_mutex );
			LDAP_TAILQ_FOREACH( tmplc,
				&li->li_conn_priv[ idx ].lic_priv,
				lc_q )
			{
				if ( !LDAP_BACK_CONN_BINDING( tmplc ) ) {
					break;
				}
			}

			if ( tmplc != NULL ) {
				refcnt = ++tmplc->lc_refcnt;
				ldap_back_conn_free( lc );
				lc = tmplc;
			}
			ldap_pvt_thread_mutex_unlock( &li->li_conninfo.lai_mutex );

			if ( tmplc != NULL ) {
				goto done;
			}
		}
#endif /* HAVE_TLS */

		/* Inserts the newly created ldapconn in the avl tree */
		ldap_pvt_thread_mutex_lock( &li->li_conninfo.lai_mutex );

		LDAP_BACK_CONN_ISBOUND_CLEAR( lc );

		assert( lc->lc_refcnt == 1 );

#if LDAP_BACK_PRINT_CONNTREE > 0
		ldap_back_print_conntree( li, ">>> ldap_back_getconn(insert)" );
#endif /* LDAP_BACK_PRINT_CONNTREE */
	
		if ( LDAP_BACK_PCONN_ISPRIV( lc ) ) {
			if ( li->li_conn_priv[ LDAP_BACK_CONN2PRIV( lc ) ].lic_num < li->li_conn_priv_max ) {
				LDAP_TAILQ_INSERT_TAIL( &li->li_conn_priv[ LDAP_BACK_CONN2PRIV( lc ) ].lic_priv, lc, lc_q );
				li->li_conn_priv[ LDAP_BACK_CONN2PRIV( lc ) ].lic_num++;
				LDAP_BACK_CONN_CACHED_SET( lc );

			} else {
				LDAP_BACK_CONN_TAINTED_SET( lc );
			}
			rs->sr_err = 0;

		} else {
			rs->sr_err = avl_insert( &li->li_conninfo.lai_tree, (caddr_t)lc,
				ldap_back_conndn_cmp, ldap_back_conndn_dup );
			LDAP_BACK_CONN_CACHED_SET( lc );
		}

#if LDAP_BACK_PRINT_CONNTREE > 0
		ldap_back_print_conntree( li, "<<< ldap_back_getconn(insert)" );
#endif /* LDAP_BACK_PRINT_CONNTREE */
	
		ldap_pvt_thread_mutex_unlock( &li->li_conninfo.lai_mutex );

		if ( StatslogTest( LDAP_DEBUG_TRACE ) ) {
			char	buf[ SLAP_TEXT_BUFLEN ];

			snprintf( buf, sizeof( buf ),
				"lc=%p inserted refcnt=%u rc=%d",
				(void *)lc, refcnt, rs->sr_err );
				
			Debug( LDAP_DEBUG_TRACE,
				"=>ldap_back_getconn: %s: %s\n",
				op->o_log_prefix, buf, 0 );
		}
	
		if ( !LDAP_BACK_PCONN_ISPRIV( lc ) ) {
			/* Err could be -1 in case a duplicate ldapconn is inserted */
			switch ( rs->sr_err ) {
			case 0:
				break;

			case -1:
				LDAP_BACK_CONN_CACHED_CLEAR( lc );
				if ( !( sendok & LDAP_BACK_BINDING ) && !LDAP_BACK_USE_TEMPORARIES( li ) ) {
					/* duplicate: free and try to get the newly created one */
					ldap_back_conn_free( lc );
					lc = NULL;
					goto retry_lock;
				}

				/* taint connection, so that it'll be freed when released */
				LDAP_BACK_CONN_TAINTED_SET( lc );
				break;

			default:
				LDAP_BACK_CONN_CACHED_CLEAR( lc );
				ldap_back_conn_free( lc );
				rs->sr_err = LDAP_OTHER;
				rs->sr_text = "Proxy bind collision";
				if ( op->o_conn && ( sendok & LDAP_BACK_SENDERR ) ) {
					send_ldap_result( op, rs );
				}
				return NULL;
			}
		}

	} else {
		int	expiring = 0;

		if ( ( li->li_idle_timeout != 0 && op->o_time > lc->lc_time + li->li_idle_timeout )
			|| ( li->li_conn_ttl != 0 && op->o_time > lc->lc_create_time + li->li_conn_ttl ) )
		{
			expiring = 1;

			/* let it be used, but taint/delete it so that 
			 * no-one else can look it up any further */
			ldap_pvt_thread_mutex_lock( &li->li_conninfo.lai_mutex );

#if LDAP_BACK_PRINT_CONNTREE > 0
			ldap_back_print_conntree( li, ">>> ldap_back_getconn(timeout)" );
#endif /* LDAP_BACK_PRINT_CONNTREE */

			(void)ldap_back_conn_delete( li, lc );
			LDAP_BACK_CONN_TAINTED_SET( lc );

#if LDAP_BACK_PRINT_CONNTREE > 0
			ldap_back_print_conntree( li, "<<< ldap_back_getconn(timeout)" );
#endif /* LDAP_BACK_PRINT_CONNTREE */

			ldap_pvt_thread_mutex_unlock( &li->li_conninfo.lai_mutex );
		}

		if ( StatslogTest( LDAP_DEBUG_TRACE ) ) {
			char	buf[ SLAP_TEXT_BUFLEN ];

			snprintf( buf, sizeof( buf ),
				"conn %p fetched refcnt=%u%s",
				(void *)lc, refcnt,
				expiring ? " expiring" : "" );
			Debug( LDAP_DEBUG_TRACE,
				"=>ldap_back_getconn: %s.\n", buf, 0, 0 );
		}
	}

#ifdef HAVE_TLS
done:;
#endif /* HAVE_TLS */

	return lc;
}

void
ldap_back_release_conn_lock(
	ldapinfo_t		*li,
	ldapconn_t		**lcp,
	int			dolock )
{

	ldapconn_t	*lc = *lcp;

	if ( dolock ) {
		ldap_pvt_thread_mutex_lock( &li->li_conninfo.lai_mutex );
	}
	assert( lc->lc_refcnt > 0 );
	LDAP_BACK_CONN_BINDING_CLEAR( lc );
	lc->lc_refcnt--;
	if ( LDAP_BACK_CONN_TAINTED( lc ) ) {
		ldap_back_freeconn( li, lc, 0 );
		*lcp = NULL;
	}
	if ( dolock ) {
		ldap_pvt_thread_mutex_unlock( &li->li_conninfo.lai_mutex );
	}
}

void
ldap_back_quarantine(
	Operation	*op,
	SlapReply	*rs )
{
	ldapinfo_t		*li = (ldapinfo_t *)op->o_bd->be_private;

	slap_retry_info_t	*ri = &li->li_quarantine;

	ldap_pvt_thread_mutex_lock( &li->li_quarantine_mutex );

	if ( rs->sr_err == LDAP_UNAVAILABLE ) {
		time_t		new_last = slap_get_time();

		switch ( li->li_isquarantined ) {
		case LDAP_BACK_FQ_NO:
			if ( ri->ri_last == new_last ) {
				goto done;
			}

			Debug( LDAP_DEBUG_ANY,
				"%s: ldap_back_quarantine enter.\n",
				op->o_log_prefix, 0, 0 );

			ri->ri_idx = 0;
			ri->ri_count = 0;
			break;

		case LDAP_BACK_FQ_RETRYING:
			Debug( LDAP_DEBUG_ANY,
				"%s: ldap_back_quarantine block #%d try #%d failed.\n",
				op->o_log_prefix, ri->ri_idx, ri->ri_count );

			++ri->ri_count;
			if ( ri->ri_num[ ri->ri_idx ] != SLAP_RETRYNUM_FOREVER
				&& ri->ri_count == ri->ri_num[ ri->ri_idx ] )
			{
				ri->ri_count = 0;
				++ri->ri_idx;
			}
			break;

		default:
			break;
		}

		li->li_isquarantined = LDAP_BACK_FQ_YES;
		ri->ri_last = new_last;

	} else if ( li->li_isquarantined != LDAP_BACK_FQ_NO ) {
		if ( ri->ri_last == slap_get_time() ) {
			goto done;
		}

		Debug( LDAP_DEBUG_ANY,
			"%s: ldap_back_quarantine exit (%d) err=%d.\n",
			op->o_log_prefix, li->li_isquarantined, rs->sr_err );

		if ( li->li_quarantine_f ) {
			(void)li->li_quarantine_f( li, li->li_quarantine_p );
		}

		ri->ri_count = 0;
		ri->ri_idx = 0;
		li->li_isquarantined = LDAP_BACK_FQ_NO;
	}

done:;
	ldap_pvt_thread_mutex_unlock( &li->li_quarantine_mutex );
}

/*
 * ldap_back_dobind_int
 *
 * Note: dolock indicates whether li->li_conninfo.lai_mutex must be locked or not