Adding upstream version 2.5.13+dfsg.upstream/2.5.13+dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

18 files changed, 12103 insertions, 0 deletions

diff --git a/servers/slapd/back-asyncmeta/Makefile.in b/servers/slapd/back-asyncmeta/Makefile.in
new file mode 100644
index 0000000..c609458
--- /dev/null
+++ b/servers/slapd/back-asyncmeta/Makefile.in
@@ -0,0 +1,50 @@
+## Makefile.in for back-asyncmeta
+## $OpenLDAP$
+## This work is part of OpenLDAP Software <http://www.openldap.org/>.
+##
+## Copyright 2016-2022 The OpenLDAP Foundation.
+## Portions Copyright 2016 Symas Corporation.
+## 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 developed by Symas Corporation
+## based on back-meta module for inclusion in OpenLDAP Software.
+## This work was sponsored by Ericsson
+
+SRCS	= init.c config.c search.c message_queue.c bind.c add.c compare.c \
+		delete.c modify.c modrdn.c map.c \
+		conn.c candidates.c dncache.c meta_result.c
+OBJS	= init.lo config.lo search.lo message_queue.lo bind.lo add.lo compare.lo \
+		delete.lo modify.lo modrdn.lo map.lo \
+		conn.lo candidates.lo dncache.lo meta_result.lo
+
+LDAP_INCDIR= ../../../include
+LDAP_LIBDIR= ../../../libraries
+
+BUILD_OPT = "--enable-asyncmeta"
+BUILD_MOD = @BUILD_ASYNCMETA@
+
+mod_DEFS = -DSLAPD_IMPORT
+MOD_DEFS = $(@BUILD_ASYNCMETA@_DEFS)
+
+shared_LDAP_LIBS = $(LDAP_LIBLDAP_LA) $(LDAP_LIBLBER_LA)
+NT_LINK_LIBS = -L.. -lslapd $(LIBS) $(@BUILD_LIBS_DYNAMIC@_LDAP_LIBS)
+UNIX_LINK_LIBS = $(@BUILD_LIBS_DYNAMIC@_LDAP_LIBS)
+
+LIBBASE = back_asyncmeta
+
+XINCPATH = -I.. -I$(srcdir)/..
+XDEFS = $(MODULES_CPPFLAGS)
+
+all-local-lib:	../.backend
+
+../.backend: lib$(LIBBASE).a
+	@touch $@
diff --git a/servers/slapd/back-asyncmeta/add.c b/servers/slapd/back-asyncmeta/add.c
new file mode 100644
index 0000000..1f194ed
--- /dev/null
+++ b/servers/slapd/back-asyncmeta/add.c
@@ -0,0 +1,363 @@
+/* add.c - add request handler for back-asyncmeta */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016-2022 The OpenLDAP Foundation.
+ * Portions Copyright 2016 Symas Corporation.
+ * 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 developed by Symas Corporation
+ * based on back-meta module for inclusion in OpenLDAP Software.
+ * This work was sponsored by Ericsson. */
+
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/string.h>
+#include <ac/socket.h>
+#include "slap.h"
+#include "../../../libraries/liblber/lber-int.h"
+#include "../../../libraries/libldap/ldap-int.h"
+#include "../back-ldap/back-ldap.h"
+#include "back-asyncmeta.h"
+#include "ldap_rq.h"
+
+
+int
+asyncmeta_error_cleanup(Operation *op,
+			SlapReply *rs,
+			bm_context_t *bc,
+			a_metaconn_t *mc,
+			int candidate)
+{
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	mc->mc_conns[candidate].msc_active--;
+	if (asyncmeta_bc_in_queue(mc,bc) == NULL || bc->bc_active > 1) {
+		bc->bc_active--;
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+		return LDAP_SUCCESS;
+	}
+	asyncmeta_drop_bc(mc, bc);
+	slap_sl_mem_setctx(op->o_threadctx, op->o_tmpmemctx);
+	operation_counter_init( op, op->o_threadctx );
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+	send_ldap_result(op, rs);
+	return LDAP_SUCCESS;
+}
+
+meta_search_candidate_t
+asyncmeta_back_add_start(Operation *op,
+			 SlapReply *rs,
+			 a_metaconn_t *mc,
+			 bm_context_t *bc,
+			 int candidate,
+			 int do_lock)
+{
+	int		isupdate;
+	Attribute	*a;
+	int i;
+	LDAPMod		**attrs;
+	a_dncookie	dc;
+	a_metainfo_t	*mi = mc->mc_info;
+	a_metatarget_t	*mt = mi->mi_targets[ candidate ];
+	struct berval   mdn = {0, NULL};
+	meta_search_candidate_t retcode = META_SEARCH_CANDIDATE;
+	BerElement *ber = NULL;
+	a_metasingleconn_t	*msc = &mc->mc_conns[ candidate ];
+	SlapReply		*candidates = bc->candidates;
+	ber_int_t	msgid;
+	LDAPControl		**ctrls = NULL;
+	int rc;
+
+	dc.op = op;
+	dc.target = mt;
+	dc.memctx = op->o_tmpmemctx;
+	dc.to_from = MASSAGE_REQ;
+	asyncmeta_dn_massage( &dc, &op->o_req_dn, &mdn );
+
+	/* Count number of attributes in entry ( +1 ) */
+	for ( i = 1, a = op->ora_e->e_attrs; a; i++, a = a->a_next );
+
+	/* Create array of LDAPMods for ldap_add() */
+	attrs = op->o_tmpalloc(sizeof( LDAPMod * )*i, op->o_tmpmemctx);
+
+	isupdate = be_shadow_update( op );
+	for ( i = 0, a = op->ora_e->e_attrs; a; a = a->a_next ) {
+		int j;
+
+		if ( !isupdate && !get_relax( op ) && a->a_desc->ad_type->sat_no_user_mod  )
+		{
+			continue;
+		}
+
+		attrs[ i ] = op->o_tmpalloc( sizeof( LDAPMod ), op->o_tmpmemctx );
+		if ( attrs[ i ] == NULL ) {
+			continue;
+		}
+		attrs[ i ]->mod_op = LDAP_MOD_BVALUES;
+		attrs[ i ]->mod_type = a->a_desc->ad_cname.bv_val;
+		j = a->a_numvals;
+		attrs[ i ]->mod_bvalues = op->o_tmpalloc( ( j + 1 ) * sizeof( struct berval * ), op->o_tmpmemctx );
+		for (j=0; j<a->a_numvals; j++) {
+			attrs[ i ]->mod_bvalues[ j ] = op->o_tmpalloc( sizeof( struct berval ), op->o_tmpmemctx );
+			if ( a->a_desc->ad_type->sat_syntax == slap_schema.si_syn_distinguishedName )
+				asyncmeta_dn_massage( &dc, &a->a_vals[ j ], attrs[ i ]->mod_bvalues[ j ] );
+			else
+				*attrs[ i ]->mod_bvalues[ j ] = a->a_vals[ j ];
+		}
+
+		attrs[ i ]->mod_bvalues[ j ] = NULL;
+		i++;
+	}
+	attrs[ i ] = NULL;
+
+	asyncmeta_set_msc_time(msc);
+
+	ctrls = op->o_ctrls;
+	if ( asyncmeta_controls_add( op, rs, mc, candidate, bc->is_root, &ctrls ) != LDAP_SUCCESS )
+	{
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		retcode = META_SEARCH_ERR;
+		goto done;
+	}
+	/* someone might have reset the connection */
+	if (!( LDAP_BACK_CONN_ISBOUND( msc )
+	       || LDAP_BACK_CONN_ISANON( msc )) || msc->msc_ld == NULL ) {
+		Debug( asyncmeta_debug, "msc %p not initialized at %s:%d\n", msc, __FILE__, __LINE__ );
+		goto error_unavailable;
+	}
+
+	ber = ldap_build_add_req( msc->msc_ld, mdn.bv_val, attrs, ctrls, NULL, &msgid);
+	if (!ber) {
+		Debug( asyncmeta_debug, "%s asyncmeta_back_add_start: Operation encoding failed with errno %d\n",
+		       op->o_log_prefix, msc->msc_ld->ld_errno );
+		rs->sr_err = LDAP_OPERATIONS_ERROR;
+		rs->sr_text = "Failed to encode proxied request";
+		retcode = META_SEARCH_ERR;
+		goto done;
+	}
+
+	if (ber) {
+		struct timeval tv = {0, mt->mt_network_timeout*1000};
+		ber_socket_t s;
+		if (!( LDAP_BACK_CONN_ISBOUND( msc )
+		       || LDAP_BACK_CONN_ISANON( msc )) || msc->msc_ld == NULL ) {
+			Debug( asyncmeta_debug, "msc %p not initialized at %s:%d\n", msc, __FILE__, __LINE__ );
+			goto error_unavailable;
+		}
+		ldap_get_option( msc->msc_ld, LDAP_OPT_DESC, &s );
+		if (s < 0) {
+			Debug( asyncmeta_debug, "msc %p not initialized at %s:%d\n", msc, __FILE__, __LINE__ );
+			goto error_unavailable;
+		}
+
+		rc = ldap_int_poll( msc->msc_ld, s, &tv, 1);
+		if (rc < 0) {
+			Debug( asyncmeta_debug, "msc %p not writable within network timeout %s:%d\n", msc, __FILE__, __LINE__ );
+			if ((msc->msc_result_time + META_BACK_RESULT_INTERVAL) < slap_get_time()) {
+				rc = LDAP_SERVER_DOWN;
+			} else {
+				goto error_unavailable;
+			}
+		} else {
+			candidates[ candidate ].sr_msgid = msgid;
+			rc = ldap_send_initial_request( msc->msc_ld, LDAP_REQ_ADD,
+							mdn.bv_val, ber, msgid );
+			if (rc == msgid)
+				rc = LDAP_SUCCESS;
+			else
+				rc = LDAP_SERVER_DOWN;
+			ber = NULL;
+		}
+
+		switch ( rc ) {
+		case LDAP_SUCCESS:
+			retcode = META_SEARCH_CANDIDATE;
+			asyncmeta_set_msc_time(msc);
+			goto done;
+
+		case LDAP_SERVER_DOWN:
+			/* do not lock if called from asyncmeta_handle_bind_result. Also do not reset the connection */
+			if (do_lock > 0) {
+				ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+				asyncmeta_reset_msc(NULL, mc, candidate, 0, __FUNCTION__);
+				ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			}
+			/* fall though*/
+		default:
+			Debug( asyncmeta_debug, "msc %p ldap_send_initial_request failed. %s:%d\n", msc, __FILE__, __LINE__ );
+			goto error_unavailable;
+		}
+	}
+
+error_unavailable:
+	if (ber)
+		ber_free(ber, 1);
+	switch (bc->nretries[candidate]) {
+	case -1: /* nretries = forever */
+		ldap_pvt_thread_yield();
+		retcode = META_SEARCH_NEED_BIND;
+		break;
+	case 0: /* no retries left */
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		rs->sr_err = LDAP_UNAVAILABLE;
+		rs->sr_text = "Unable to send add request to target";
+		retcode = META_SEARCH_ERR;
+		break;
+	default: /* more retries left - try to rebind and go again */
+		retcode = META_SEARCH_NEED_BIND;
+		bc->nretries[candidate]--;
+		ldap_pvt_thread_yield();
+		break;
+	}
+
+done:
+	(void)mi->mi_ldap_extra->controls_free( op, rs, &ctrls );
+
+	if ( mdn.bv_val != op->o_req_dn.bv_val ) {
+		op->o_tmpfree( mdn.bv_val, op->o_tmpmemctx );
+	}
+
+	Debug( LDAP_DEBUG_TRACE, "%s <<< asyncmeta_back_add_start[%p]=%d\n", op->o_log_prefix, msc, candidates[candidate].sr_msgid );
+	return retcode;
+}
+
+
+int
+asyncmeta_back_add( Operation *op, SlapReply *rs )
+{
+	a_metainfo_t	*mi = ( a_metainfo_t * )op->o_bd->be_private;
+	a_metatarget_t	*mt;
+	a_metaconn_t	*mc;
+	int		rc, candidate = -1;
+	void *thrctx = op->o_threadctx;
+	bm_context_t *bc;
+	SlapReply *candidates;
+	time_t current_time = slap_get_time();
+	int max_pending_ops = (mi->mi_max_pending_ops == 0) ? META_BACK_CFG_MAX_PENDING_OPS : mi->mi_max_pending_ops;
+
+	Debug(LDAP_DEBUG_TRACE, "==> asyncmeta_back_add: %s\n",
+	      op->o_req_dn.bv_val );
+
+	if (current_time > op->o_time) {
+		Debug(asyncmeta_debug, "==> asyncmeta_back_add[%s]: o_time:[%ld], current time: [%ld]\n",
+		      op->o_log_prefix, op->o_time, current_time );
+	}
+
+	asyncmeta_new_bm_context(op, rs, &bc, mi->mi_ntargets, mi );
+	if (bc == NULL) {
+		rs->sr_err = LDAP_OTHER;
+		send_ldap_result(op, rs);
+		return rs->sr_err;
+	}
+
+	candidates = bc->candidates;
+	mc = asyncmeta_getconn( op, rs, candidates, &candidate, LDAP_BACK_DONTSEND, 0);
+	if ( !mc || rs->sr_err != LDAP_SUCCESS) {
+		send_ldap_result(op, rs);
+		return rs->sr_err;
+	}
+
+	mt = mi->mi_targets[ candidate ];
+	bc->timeout = mt->mt_timeout[ SLAP_OP_ADD ];
+	bc->retrying = LDAP_BACK_RETRYING;
+	bc->sendok = ( LDAP_BACK_SENDRESULT | bc->retrying );
+	bc->stoptime = op->o_time + bc->timeout;
+	bc->bc_active = 1;
+
+	if (mc->pending_ops >= max_pending_ops) {
+		rs->sr_err = LDAP_BUSY;
+		rs->sr_text = "Maximum pending ops limit exceeded";
+		send_ldap_result(op, rs);
+		return rs->sr_err;
+	}
+
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	rc = asyncmeta_add_message_queue(mc, bc);
+	mc->mc_conns[candidate].msc_active++;
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+
+	if (rc != LDAP_SUCCESS) {
+		rs->sr_err = LDAP_BUSY;
+		rs->sr_text = "Maximum pending ops limit exceeded";
+		send_ldap_result(op, rs);
+		ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+		mc->mc_conns[candidate].msc_active--;
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+		goto finish;
+	}
+
+retry:
+	current_time = slap_get_time();
+	if (bc->timeout && bc->stoptime < current_time) {
+		int		timeout_err;
+		timeout_err = op->o_protocol >= LDAP_VERSION3 ?
+			LDAP_ADMINLIMIT_EXCEEDED : LDAP_OTHER;
+		rs->sr_err = timeout_err;
+		rs->sr_text = "Operation timed out before it was sent to target";
+		asyncmeta_error_cleanup(op, rs, bc, mc, candidate);
+		goto finish;
+	}
+
+	rc = asyncmeta_dobind_init_with_retry(op, rs, bc, mc, candidate);
+	switch (rc)
+	{
+	case META_SEARCH_CANDIDATE:
+		/* target is already bound, just send the request */
+		Debug(LDAP_DEBUG_TRACE , "%s asyncmeta_back_add:  "
+		       "cnd=\"%d\"\n", op->o_log_prefix, candidate );
+
+		rc = asyncmeta_back_add_start( op, rs, mc, bc, candidate, 1);
+		if (rc == META_SEARCH_ERR) {
+			asyncmeta_error_cleanup(op, rs, bc, mc, candidate);
+			goto finish;
+
+		} else if (rc == META_SEARCH_NEED_BIND) {
+			goto retry;
+		}
+		break;
+	case META_SEARCH_NOT_CANDIDATE:
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_add: NOT_CANDIDATE "
+		       "cnd=\"%d\"\n", op->o_log_prefix, candidate );
+		asyncmeta_error_cleanup(op, rs, bc, mc, candidate);
+		goto finish;
+
+	case META_SEARCH_NEED_BIND:
+	case META_SEARCH_BINDING:
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_add: BINDING "
+		       "cnd=\"%d\" %p\n", op->o_log_prefix, candidate , &mc->mc_conns[candidate]);
+		/* add the context to the message queue but do not send the request
+		   the receiver must send this when we are done binding */
+		break;
+
+	case META_SEARCH_ERR:
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_add: ERR "
+		       "cnd=\"%d\"\n", op->o_log_prefix, candidate );
+		asyncmeta_error_cleanup(op, rs, bc, mc, candidate);
+		goto finish;
+	default:
+		assert( 0 );
+		break;
+	}
+
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	mc->mc_conns[candidate].msc_active--;
+	asyncmeta_start_one_listener(mc, candidates, bc, candidate);
+	bc->bc_active--;
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+	rs->sr_err = SLAPD_ASYNCOP;
+finish:
+	return rs->sr_err;
+}
diff --git a/servers/slapd/back-asyncmeta/back-asyncmeta.h b/servers/slapd/back-asyncmeta/back-asyncmeta.h
new file mode 100644
index 0000000..f3ce06e
--- /dev/null
+++ b/servers/slapd/back-asyncmeta/back-asyncmeta.h
@@ -0,0 +1,782 @@
+/* back-asyncmeta.h - main header file for back-asyncmeta module */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016-2022 The OpenLDAP Foundation.
+ * Portions Copyright 2016 Symas Corporation.
+ * 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 developed by Symas Corporation
+ * based on back-meta module for inclusion in OpenLDAP Software.
+ * This work was sponsored by Ericsson. */
+
+#ifndef SLAPD_LDAP_H
+#error "include servers/slapd/back-ldap/back-ldap.h before this file!"
+#endif /* SLAPD_LDAP_H */
+
+#ifndef SLAPD_ASYNCMETA_H
+#define SLAPD_ASYNCMETA_H
+
+#ifdef LDAP_DEVEL
+#define SLAPD_META_CLIENT_PR 1
+#endif /* LDAP_DEVEL */
+
+#include "proto-asyncmeta.h"
+
+#include "ldap_rq.h"
+
+LDAP_BEGIN_DECL
+
+/*
+ * Set META_BACK_PRINT_CONNTREE larger than 0 to dump the connection tree (debug only)
+ */
+#ifndef META_BACK_PRINT_CONNTREE
+#define META_BACK_PRINT_CONNTREE 0
+#endif /* !META_BACK_PRINT_CONNTREE */
+
+/*
+ * A a_metasingleconn_t can be in the following, mutually exclusive states:
+ *
+ *	- none			(0x0U)
+ *	- creating		META_BACK_FCONN_CREATING
+ *	- initialized		META_BACK_FCONN_INITED
+ *	- binding		LDAP_BACK_FCONN_BINDING
+ *	- bound/anonymous	LDAP_BACK_FCONN_ISBOUND/LDAP_BACK_FCONN_ISANON
+ *
+ * possible modifiers are:
+ *
+ *	- privileged		LDAP_BACK_FCONN_ISPRIV
+ *	- privileged, TLS	LDAP_BACK_FCONN_ISTLS
+ *	- subjected to idassert	LDAP_BACK_FCONN_ISIDASR
+ *	- tainted		LDAP_BACK_FCONN_TAINTED
+ */
+
+#define META_BACK_FCONN_INITED		(0x00100000U)
+#define META_BACK_FCONN_CREATING	(0x00200000U)
+#define META_BACK_FCONN_INVALID	        (0x00400000U)
+
+#define	META_BACK_CONN_INITED(lc)		LDAP_BACK_CONN_ISSET((lc), META_BACK_FCONN_INITED)
+#define	META_BACK_CONN_INITED_SET(lc)		LDAP_BACK_CONN_SET((lc), META_BACK_FCONN_INITED)
+#define	META_BACK_CONN_INITED_CLEAR(lc)		LDAP_BACK_CONN_CLEAR((lc), META_BACK_FCONN_INITED)
+#define	META_BACK_CONN_INITED_CPY(lc, mlc)	LDAP_BACK_CONN_CPY((lc), META_BACK_FCONN_INITED, (mlc))
+#define	META_BACK_CONN_CREATING(lc)		LDAP_BACK_CONN_ISSET((lc), META_BACK_FCONN_CREATING)
+#define	META_BACK_CONN_CREATING_SET(lc)		LDAP_BACK_CONN_SET((lc), META_BACK_FCONN_CREATING)
+#define	META_BACK_CONN_CREATING_CLEAR(lc)	LDAP_BACK_CONN_CLEAR((lc), META_BACK_FCONN_CREATING)
+#define	META_BACK_CONN_CREATING_CPY(lc, mlc)	LDAP_BACK_CONN_CPY((lc), META_BACK_FCONN_CREATING, (mlc))
+#define	META_BACK_CONN_INVALID(lc)		LDAP_BACK_CONN_ISSET((lc), META_BACK_FCONN_INVALID)
+#define	META_BACK_CONN_INVALID_SET(lc)		LDAP_BACK_CONN_SET((lc), META_BACK_FCONN_INVALID)
+#define	META_BACK_CONN_INVALID_CLEAR(lc)	LDAP_BACK_CONN_CLEAR((lc), META_BACK_FCONN_INVALID)
+
+struct a_metainfo_t;
+struct a_metaconn_t;
+struct a_metatarget_t;
+#define	META_NOT_CANDIDATE		((ber_tag_t)0x0)
+#define	META_CANDIDATE			((ber_tag_t)0x1)
+#define	META_BINDING			((ber_tag_t)0x2)
+#define	META_RETRYING			((ber_tag_t)0x4)
+
+typedef struct bm_context_t {
+	LDAP_STAILQ_ENTRY(bm_context_t) bc_next;
+	struct a_metaconn_t *bc_mc;
+	time_t			timeout;
+	time_t                  stoptime;
+	ldap_back_send_t	sendok;
+	ldap_back_send_t	retrying;
+	int candidate_match;
+	volatile int bc_active;
+	int searchtime;	/* stoptime is a search timelimit */
+	int is_ok;
+	int is_root;
+	volatile sig_atomic_t bc_invalid;
+	SlapReply		rs;
+	Operation		*op;
+	Operation               copy_op;
+	LDAPControl	        **ctrls;
+	int                     *msgids;
+	int                     *nretries;  /* number of times to retry a failed send on an msc */
+	struct berval	        c_peer_name; /* peer name of original op->o_conn*/
+	SlapReply               *candidates;
+} bm_context_t;
+
+typedef struct a_metasingleconn_t {
+#define META_CND_ISSET(rs,f)		( ( (rs)->sr_tag & (f) ) == (f) )
+#define META_CND_SET(rs,f)		( (rs)->sr_tag |= (f) )
+#define META_CND_CLEAR(rs,f)		( (rs)->sr_tag &= ~(f) )
+
+#define META_CANDIDATE_RESET(rs)	( (rs)->sr_tag = 0 )
+#define META_IS_CANDIDATE(rs)		META_CND_ISSET( (rs), META_CANDIDATE )
+#define META_CANDIDATE_SET(rs)		META_CND_SET( (rs), META_CANDIDATE )
+#define META_CANDIDATE_CLEAR(rs)	META_CND_CLEAR( (rs), META_CANDIDATE )
+#define META_IS_BINDING(rs)		META_CND_ISSET( (rs), META_BINDING )
+#define META_BINDING_SET(rs)		META_CND_SET( (rs), META_BINDING )
+#define META_BINDING_CLEAR(rs)		META_CND_CLEAR( (rs), META_BINDING )
+#define META_IS_RETRYING(rs)		META_CND_ISSET( (rs), META_RETRYING )
+#define META_RETRYING_SET(rs)		META_CND_SET( (rs), META_RETRYING )
+#define META_RETRYING_CLEAR(rs)		META_CND_CLEAR( (rs), META_RETRYING )
+
+	LDAP            	*msc_ld;
+	LDAP            	*msc_ldr;
+	time_t			msc_time;
+	time_t                  msc_binding_time;
+	time_t                  msc_result_time;
+	struct berval          	msc_bound_ndn;
+	struct berval		msc_cred;
+	unsigned		msc_mscflags;
+
+	/* NOTE: lc_lcflags is redefined to msc_mscflags to reuse the macros
+	 * defined for back-ldap */
+#define	lc_lcflags		msc_mscflags
+	volatile int msc_active;
+		/* Connection for the select */
+	Connection *conn;
+} a_metasingleconn_t;
+
+typedef struct a_metaconn_t {
+	ldapconn_base_t		lc_base;
+#define	mc_base			lc_base
+//#define	mc_conn			mc_base.lcb_conn
+//#define	mc_local_ndn		mc_base.lcb_local_ndn
+//#define	mc_refcnt		mc_base.lcb_refcnt
+//#define	mc_create_time		mc_base.lcb_create_time
+//#define	mc_time			mc_base.lcb_time
+
+	LDAP_TAILQ_ENTRY(a_metaconn_t)	mc_q;
+
+	/* NOTE: msc_mscflags is used to recycle the #define
+	 * in metasingleconn_t */
+	unsigned		msc_mscflags;
+	int	mc_active;
+
+	/*
+	 * means that the connection is bound;
+	 * of course only one target actually is ...
+	 */
+	int             	mc_authz_target;
+#define META_BOUND_NONE		(-1)
+#define META_BOUND_ALL		(-2)
+
+	struct a_metainfo_t	*mc_info;
+
+	int pending_ops;
+	ldap_pvt_thread_mutex_t	mc_om_mutex;
+	/* queue for pending operations */
+	LDAP_STAILQ_HEAD(BCList, bm_context_t) mc_om_list;
+	/* supersedes the connection stuff */
+	a_metasingleconn_t	*mc_conns;
+} a_metaconn_t;
+
+typedef enum meta_st_t {
+#if 0 /* todo */
+	META_ST_EXACT = LDAP_SCOPE_BASE,
+#endif
+	META_ST_SUBTREE = LDAP_SCOPE_SUBTREE,
+	META_ST_SUBORDINATE = LDAP_SCOPE_SUBORDINATE,
+	META_ST_REGEX /* last + 1 */
+} meta_st_t;
+
+typedef struct a_metasubtree_t {
+	meta_st_t ms_type;
+	union {
+		struct berval msu_dn;
+		struct {
+			struct berval msr_regex_pattern;
+			regex_t msr_regex;
+		} msu_regex;
+	} ms_un;
+#define ms_dn ms_un.msu_dn
+#define ms_regex ms_un.msu_regex.msr_regex
+#define ms_regex_pattern ms_un.msu_regex.msr_regex_pattern
+
+	struct a_metasubtree_t *ms_next;
+} a_metasubtree_t;
+
+typedef struct metafilter_t {
+	struct metafilter_t *mf_next;
+	struct berval mf_regex_pattern;
+	regex_t mf_regex;
+} metafilter_t;
+
+typedef struct a_metacommon_t {
+	int				mc_version;
+	int				mc_nretries;
+#define META_RETRY_UNDEFINED	(-2)
+#define META_RETRY_FOREVER	(-1)
+#define META_RETRY_NEVER	(0)
+#define META_RETRY_DEFAULT	(2)
+
+	unsigned		mc_flags;
+#define	META_BACK_CMN_ISSET(mc,f)		( ( (mc)->mc_flags & (f) ) == (f) )
+#define	META_BACK_CMN_QUARANTINE(mc)		META_BACK_CMN_ISSET( (mc), LDAP_BACK_F_QUARANTINE )
+#define	META_BACK_CMN_CHASE_REFERRALS(mc)	META_BACK_CMN_ISSET( (mc), LDAP_BACK_F_CHASE_REFERRALS )
+#define	META_BACK_CMN_NOREFS(mc)		META_BACK_CMN_ISSET( (mc), LDAP_BACK_F_NOREFS )
+#define	META_BACK_CMN_NOUNDEFFILTER(mc)		META_BACK_CMN_ISSET( (mc), LDAP_BACK_F_NOUNDEFFILTER )
+#define	META_BACK_CMN_SAVECRED(mc)		META_BACK_CMN_ISSET( (mc), LDAP_BACK_F_SAVECRED )
+#define	META_BACK_CMN_ST_REQUEST(mc)		META_BACK_CMN_ISSET( (mc), LDAP_BACK_F_ST_REQUEST )
+
+#ifdef SLAPD_META_CLIENT_PR
+	/*
+	 * client-side paged results:
+	 * -1: accept unsolicited paged results responses
+	 *  0: off
+	 * >0: always request paged results with size == mt_ps
+	 */
+#define META_CLIENT_PR_DISABLE			(0)
+#define META_CLIENT_PR_ACCEPT_UNSOLICITED	(-1)
+	ber_int_t		mc_ps;
+#endif /* SLAPD_META_CLIENT_PR */
+
+	slap_retry_info_t	mc_quarantine;
+	time_t			mc_network_timeout;
+	struct timeval	mc_bind_timeout;
+#define META_BIND_TIMEOUT	LDAP_BACK_RESULT_UTIMEOUT
+	time_t			mc_timeout[ SLAP_OP_LAST ];
+} a_metacommon_t;
+
+typedef struct a_metatarget_t {
+	char			*mt_uri;
+	ldap_pvt_thread_mutex_t	mt_uri_mutex;
+
+	/* TODO: we might want to enable different strategies
+	 * for different targets */
+	LDAP_REBIND_PROC	*mt_rebind_f;
+	LDAP_URLLIST_PROC	*mt_urllist_f;
+	void			*mt_urllist_p;
+
+	metafilter_t	*mt_filter;
+	a_metasubtree_t		*mt_subtree;
+	/* F: subtree-include; T: subtree-exclude */
+	int			mt_subtree_exclude;
+
+	int			mt_scope;
+
+	struct berval		mt_psuffix;		/* pretty suffix */
+	struct berval		mt_nsuffix;		/* normalized suffix */
+
+	struct berval		mt_lsuffixm;	/* local suffix for massage */
+	struct berval		mt_rsuffixm;	/* remote suffix for massage */
+
+	struct berval		mt_binddn;
+	struct berval		mt_bindpw;
+
+	/* we only care about the TLS options here */
+	slap_bindconf		mt_tls;
+
+	slap_idassert_t		mt_idassert;
+#define	mt_idassert_mode	mt_idassert.si_mode
+#define	mt_idassert_authcID	mt_idassert.si_bc.sb_authcId
+#define	mt_idassert_authcDN	mt_idassert.si_bc.sb_binddn
+#define	mt_idassert_passwd	mt_idassert.si_bc.sb_cred
+#define	mt_idassert_authzID	mt_idassert.si_bc.sb_authzId
+#define	mt_idassert_authmethod	mt_idassert.si_bc.sb_method
+#define	mt_idassert_sasl_mech	mt_idassert.si_bc.sb_saslmech
+#define	mt_idassert_sasl_realm	mt_idassert.si_bc.sb_realm
+#define	mt_idassert_secprops	mt_idassert.si_bc.sb_secprops
+#define	mt_idassert_tls		mt_idassert.si_bc.sb_tls
+#define	mt_idassert_flags	mt_idassert.si_flags
+#define	mt_idassert_authz	mt_idassert.si_authz
+
+	sig_atomic_t		mt_isquarantined;
+	ldap_pvt_thread_mutex_t	mt_quarantine_mutex;
+
+	a_metacommon_t	mt_mc;
+#define	mt_nretries	mt_mc.mc_nretries
+#define	mt_flags	mt_mc.mc_flags
+#define	mt_version	mt_mc.mc_version
+#define	mt_ps		mt_mc.mc_ps
+#define	mt_network_timeout	mt_mc.mc_network_timeout
+#define	mt_bind_timeout	mt_mc.mc_bind_timeout
+#define	mt_timeout	mt_mc.mc_timeout
+#define	mt_quarantine	mt_mc.mc_quarantine
+
+#define	META_BACK_TGT_ISSET(mt,f)		( ( (mt)->mt_flags & (f) ) == (f) )
+#define	META_BACK_TGT_ISMASK(mt,m,f)		( ( (mt)->mt_flags & (m) ) == (f) )
+
+#define META_BACK_TGT_SAVECRED(mt)		META_BACK_TGT_ISSET( (mt), LDAP_BACK_F_SAVECRED )
+
+#define META_BACK_TGT_USE_TLS(mt)		META_BACK_TGT_ISSET( (mt), LDAP_BACK_F_USE_TLS )
+#define META_BACK_TGT_PROPAGATE_TLS(mt)		META_BACK_TGT_ISSET( (mt), LDAP_BACK_F_PROPAGATE_TLS )
+#define META_BACK_TGT_TLS_CRITICAL(mt)		META_BACK_TGT_ISSET( (mt), LDAP_BACK_F_TLS_CRITICAL )
+
+#define META_BACK_TGT_CHASE_REFERRALS(mt)	META_BACK_TGT_ISSET( (mt), LDAP_BACK_F_CHASE_REFERRALS )
+
+#define	META_BACK_TGT_T_F(mt)			META_BACK_TGT_ISMASK( (mt), LDAP_BACK_F_T_F_MASK, LDAP_BACK_F_T_F )
+#define	META_BACK_TGT_T_F_DISCOVER(mt)		META_BACK_TGT_ISMASK( (mt), LDAP_BACK_F_T_F_MASK2, LDAP_BACK_F_T_F_DISCOVER )
+
+#define	META_BACK_TGT_ABANDON(mt)		META_BACK_TGT_ISMASK( (mt), LDAP_BACK_F_CANCEL_MASK, LDAP_BACK_F_CANCEL_ABANDON )
+#define	META_BACK_TGT_IGNORE(mt)		META_BACK_TGT_ISMASK( (mt), LDAP_BACK_F_CANCEL_MASK, LDAP_BACK_F_CANCEL_IGNORE )
+#define	META_BACK_TGT_CANCEL(mt)		META_BACK_TGT_ISMASK( (mt), LDAP_BACK_F_CANCEL_MASK, LDAP_BACK_F_CANCEL_EXOP )
+#define	META_BACK_TGT_CANCEL_DISCOVER(mt)	META_BACK_TGT_ISMASK( (mt), LDAP_BACK_F_CANCEL_MASK2, LDAP_BACK_F_CANCEL_EXOP_DISCOVER )
+#define	META_BACK_TGT_QUARANTINE(mt)		META_BACK_TGT_ISSET( (mt), LDAP_BACK_F_QUARANTINE )
+
+#ifdef SLAP_CONTROL_X_SESSION_TRACKING
+#define	META_BACK_TGT_ST_REQUEST(mt)		META_BACK_TGT_ISSET( (mt), LDAP_BACK_F_ST_REQUEST )
+#define	META_BACK_TGT_ST_RESPONSE(mt)		META_BACK_TGT_ISSET( (mt), LDAP_BACK_F_ST_RESPONSE )
+#endif /* SLAP_CONTROL_X_SESSION_TRACKING */
+
+#define	META_BACK_TGT_NOREFS(mt)		META_BACK_TGT_ISSET( (mt), LDAP_BACK_F_NOREFS )
+#define	META_BACK_TGT_NOUNDEFFILTER(mt)		META_BACK_TGT_ISSET( (mt), LDAP_BACK_F_NOUNDEFFILTER )
+
+#define META_BACK_CFG_MAX_PENDING_OPS		0x80
+#define META_BACK_CFG_MAX_TARGET_CONNS		0xFF
+#define META_BACK_CFG_DEFAULT_OPS_TIMEOUT	0x02
+
+/* the interval of the timeout checking loop in microseconds
+ * possibly make this configurable? */
+#define META_BACK_CFG_MAX_TIMEOUT_LOOP		0x70000
+	slap_mask_t		mt_rep_flags;
+	int			mt_timeout_ops;
+} a_metatarget_t;
+
+typedef struct a_metadncache_t {
+	ldap_pvt_thread_mutex_t mutex;
+	Avlnode			*tree;
+
+#define META_DNCACHE_DISABLED   (0)
+#define META_DNCACHE_FOREVER    ((time_t)(-1))
+	time_t			ttl;  /* seconds; 0: no cache, -1: no expiry */
+} a_metadncache_t;
+
+typedef struct a_metacandidates_t {
+	int			mc_ntargets;
+	SlapReply		*mc_candidates;
+} a_metacandidates_t;
+
+/*
+ * Hook to allow mucking with a_metainfo_t/a_metatarget_t when quarantine is over
+ */
+typedef int (*asyncmeta_quarantine_f)( struct a_metainfo_t *, int target, void * );
+
+struct meta_out_message_t;
+
+typedef struct a_metainfo_t {
+	int			mi_ntargets;
+	int			mi_defaulttarget;
+#define META_DEFAULT_TARGET_NONE	(-1)
+
+#define	mi_nretries	mi_mc.mc_nretries
+#define	mi_flags	mi_mc.mc_flags
+#define	mi_version	mi_mc.mc_version
+#define	mi_ps		mi_mc.mc_ps
+#define	mi_network_timeout	mi_mc.mc_network_timeout
+#define	mi_bind_timeout	mi_mc.mc_bind_timeout
+#define	mi_timeout	mi_mc.mc_timeout
+#define	mi_quarantine	mi_mc.mc_quarantine
+
+	a_metatarget_t		**mi_targets;
+	a_metacandidates_t	*mi_candidates;
+
+	LDAP_REBIND_PROC	*mi_rebind_f;
+	LDAP_URLLIST_PROC	*mi_urllist_f;
+
+	a_metadncache_t		mi_cache;
+
+	struct {
+		int						mic_num;
+		LDAP_TAILQ_HEAD(mc_conn_priv_q, a_metaconn_t)	mic_priv;
+	}			mi_conn_priv[ LDAP_BACK_PCONN_LAST ];
+	int			mi_conn_priv_max;
+
+	/* NOTE: quarantine uses the connection mutex */
+	asyncmeta_quarantine_f	mi_quarantine_f;
+	void			*mi_quarantine_p;
+
+#define	li_flags		mi_flags
+/* uses flags as defined in <back-ldap/back-ldap.h> */
+#define	META_BACK_F_ONERR_STOP		LDAP_BACK_F_ONERR_STOP
+#define	META_BACK_F_ONERR_REPORT	(0x02000000U)
+#define	META_BACK_F_ONERR_MASK		(META_BACK_F_ONERR_STOP|META_BACK_F_ONERR_REPORT)
+#define	META_BACK_F_DEFER_ROOTDN_BIND	(0x04000000U)
+#define	META_BACK_F_PROXYAUTHZ_ALWAYS	(0x08000000U)	/* users always proxyauthz */
+#define	META_BACK_F_PROXYAUTHZ_ANON	(0x10000000U)	/* anonymous always proxyauthz */
+#define	META_BACK_F_PROXYAUTHZ_NOANON	(0x20000000U)	/* anonymous remains anonymous */
+
+#define	META_BACK_ONERR_STOP(mi)	LDAP_BACK_ISSET( (mi), META_BACK_F_ONERR_STOP )
+#define	META_BACK_ONERR_REPORT(mi)	LDAP_BACK_ISSET( (mi), META_BACK_F_ONERR_REPORT )
+#define	META_BACK_ONERR_CONTINUE(mi)	( !LDAP_BACK_ISSET( (mi), META_BACK_F_ONERR_MASK ) )
+
+#define META_BACK_DEFER_ROOTDN_BIND(mi)	LDAP_BACK_ISSET( (mi), META_BACK_F_DEFER_ROOTDN_BIND )
+#define META_BACK_PROXYAUTHZ_ALWAYS(mi)	LDAP_BACK_ISSET( (mi), META_BACK_F_PROXYAUTHZ_ALWAYS )
+#define META_BACK_PROXYAUTHZ_ANON(mi)	LDAP_BACK_ISSET( (mi), META_BACK_F_PROXYAUTHZ_ANON )
+#define META_BACK_PROXYAUTHZ_NOANON(mi)	LDAP_BACK_ISSET( (mi), META_BACK_F_PROXYAUTHZ_NOANON )
+
+#define META_BACK_QUARANTINE(mi)	LDAP_BACK_ISSET( (mi), LDAP_BACK_F_QUARANTINE )
+
+	time_t			mi_idle_timeout;
+	struct re_s *mi_task;
+
+	a_metacommon_t	mi_mc;
+	ldap_extra_t	*mi_ldap_extra;
+
+	int                    mi_max_timeout_ops;
+	int                    mi_max_pending_ops;
+	int                    mi_max_target_conns;
+	/* mutex for access to the connection structures */
+	ldap_pvt_thread_mutex_t	mi_mc_mutex;
+	int                    mi_num_conns;
+	int                    mi_next_conn;
+	a_metaconn_t          *mi_conns;
+
+	struct berval		mi_suffix;
+} a_metainfo_t;
+
+typedef enum meta_op_type {
+	META_OP_ALLOW_MULTIPLE = 0,
+	META_OP_REQUIRE_SINGLE,
+	META_OP_REQUIRE_ALL
+} meta_op_type;
+
+/* Whatever context asyncmeta_dn_massage needs... */
+typedef struct a_dncookie {
+	Operation		*op;
+	struct a_metatarget_t	*target;
+	void	*memctx;
+	int	to_from;
+} a_dncookie;
+
+
+#define MASSAGE_REQ	0
+#define MASSAGE_REP	1
+
+extern void
+asyncmeta_dn_massage(a_dncookie *dc, struct berval *dn,
+	struct berval *res);
+
+extern void
+asyncmeta_filter_map_rewrite(
+	a_dncookie	*dc,
+	Filter		*f,
+	struct berval	*fstr );
+
+extern void
+asyncmeta_back_referral_result_rewrite(
+	a_dncookie	*dc,
+	BerVarray	a_vals );
+
+extern a_metaconn_t *
+asyncmeta_getconn(
+	Operation		*op,
+	SlapReply		*rs,
+	SlapReply               *candidates,
+	int			*candidate,
+	ldap_back_send_t	sendok,
+	int                     alloc_new);
+
+
+extern int
+asyncmeta_init_one_conn(
+	Operation		*op,
+	SlapReply		*rs,
+	a_metaconn_t		*mc,
+	int			candidate,
+	int			ispriv,
+	ldap_back_send_t	sendok,
+	int			dolock );
+
+extern void
+asyncmeta_quarantine(
+	Operation		*op,
+	a_metainfo_t            *mi,
+	SlapReply		*rs,
+	int			candidate );
+
+extern int
+asyncmeta_proxy_authz_cred(
+	a_metaconn_t		*mc,
+	int			candidate,
+	Operation		*op,
+	SlapReply		*rs,
+	ldap_back_send_t	sendok,
+	struct berval		*binddn,
+	struct berval		*bindcred,
+	int			*method );
+
+extern int
+asyncmeta_controls_add(
+	Operation	*op,
+	SlapReply	*rs,
+	a_metaconn_t	*mc,
+	int		candidate,
+	int             isroot,
+	LDAPControl	***pctrls );
+
+extern int
+asyncmeta_LTX_init_module(
+	int			argc,
+	char			*argv[] );
+
+/*
+ * Candidate stuff
+ */
+extern int
+asyncmeta_is_candidate(
+	a_metatarget_t		*mt,
+	struct berval		*ndn,
+	int			scope );
+
+extern int
+asyncmeta_select_unique_candidate(
+	a_metainfo_t		*mi,
+	struct berval		*ndn );
+
+extern int
+asyncmeta_clear_unused_candidates(
+	Operation		*op,
+	int			candidate,
+	a_metaconn_t            *mc,
+	SlapReply	*candidates);
+
+/*
+ * Dn cache stuff (experimental)
+ */
+extern int
+asyncmeta_dncache_cmp(
+	const void		*c1,
+	const void		*c2 );
+
+extern int
+asyncmeta_dncache_dup(
+	void			*c1,
+	void			*c2 );
+
+#define META_TARGET_NONE	(-1)
+#define META_TARGET_MULTIPLE	(-2)
+extern int
+asyncmeta_dncache_get_target(
+	a_metadncache_t		*cache,
+	struct berval		*ndn );
+
+extern int
+meta_dncache_update_entry(
+	a_metadncache_t		*cache,
+	struct berval		*ndn,
+	int			target );
+
+extern int
+asyncmeta_dncache_delete_entry(
+	a_metadncache_t		*cache,
+	struct berval		*ndn );
+
+extern void
+asyncmeta_dncache_free( void *entry );
+
+extern int
+asyncmeta_subtree_destroy( a_metasubtree_t *ms );
+
+extern void
+asyncmeta_filter_destroy( metafilter_t *mf );
+
+extern int
+asyncmeta_target_finish( a_metainfo_t *mi, a_metatarget_t *mt,
+	const char *log, char *msg, size_t msize
+);
+
+
+extern LDAP_REBIND_PROC		asyncmeta_back_default_rebind;
+extern LDAP_URLLIST_PROC	asyncmeta_back_default_urllist;
+
+/* IGNORE means that target does not (no longer) participate
+ * in the search;
+ * NOTREADY means the search on that target has not been initialized yet
+ */
+#define	META_MSGID_IGNORE	(-1)
+#define	META_MSGID_NEED_BIND	(-2)
+#define	META_MSGID_CONNECTING	(-3)
+#define META_MSGID_UNDEFINED    (-4)
+#define META_MSGID_GOT_BIND     (-5)
+
+typedef enum meta_search_candidate_t {
+	META_SEARCH_UNDEFINED = -2,
+	META_SEARCH_ERR = -1,
+	META_SEARCH_NOT_CANDIDATE,
+	META_SEARCH_CANDIDATE,
+	META_SEARCH_BINDING,
+	META_SEARCH_NEED_BIND,
+	META_SEARCH_CONNECTING
+} meta_search_candidate_t;
+
+Operation* asyncmeta_copy_op(Operation *op);
+void asyncmeta_clear_bm_context(bm_context_t *bc);
+
+int asyncmeta_add_message_queue(a_metaconn_t *mc, bm_context_t *bc);
+void asyncmeta_drop_bc(a_metaconn_t *mc, bm_context_t *bc);
+void asyncmeta_drop_bc_from_fconn(bm_context_t *bc);
+
+bm_context_t *
+asyncmeta_find_message(ber_int_t msgid, a_metaconn_t *mc, int candidate);
+
+void* asyncmeta_op_handle_result(void *ctx, void *arg);
+int asyncmeta_back_cleanup( Operation *op, SlapReply *rs, bm_context_t *bm );
+
+int
+asyncmeta_clear_one_msc(
+	Operation	*op,
+	a_metaconn_t	*msc,
+	int		candidate,
+	int             unbind,
+	const char *          caller);
+
+a_metaconn_t *
+asyncmeta_get_next_mc( a_metainfo_t *mi );
+
+void* asyncmeta_timeout_loop(void *ctx, void *arg);
+
+int
+asyncmeta_start_timeout_loop(a_metatarget_t *mt, a_metainfo_t *mi);
+
+void asyncmeta_set_msc_time(a_metasingleconn_t *msc);
+
+int asyncmeta_back_cancel(
+	a_metaconn_t	*mc,
+	Operation		*op,
+	ber_int_t		msgid,
+	int				candidate );
+
+void
+asyncmeta_send_result(bm_context_t* bc, int error, char *text);
+
+int asyncmeta_new_bm_context(Operation *op,
+			     SlapReply *rs,
+			     bm_context_t **new_bc,
+			     int ntargets,
+			     a_metainfo_t       *mi);
+
+int asyncmeta_start_listeners(a_metaconn_t *mc, SlapReply *candidates,  bm_context_t *bc);
+int asyncmeta_start_one_listener(a_metaconn_t *mc, SlapReply *candidates,  bm_context_t *bc, int candidate);
+
+meta_search_candidate_t
+asyncmeta_back_search_start(
+	Operation             *op,
+	SlapReply             *rs,
+	a_metaconn_t          *mc,
+	bm_context_t          *bc,
+	int                   candidate,
+	struct berval	      *prcookie,
+	ber_int_t	      prsize,
+	int do_lock);
+
+meta_search_candidate_t
+asyncmeta_dobind_init(
+	Operation            *op,
+	SlapReply            *rs,
+	bm_context_t         *bc,
+	a_metaconn_t         *mc,
+	int                  candidate);
+
+meta_search_candidate_t
+asyncmeta_dobind_init_with_retry(
+	Operation            *op,
+	SlapReply            *rs,
+	bm_context_t         *bc,
+	a_metaconn_t         *mc,
+	int                  candidate);
+
+meta_search_candidate_t
+asyncmeta_back_add_start(Operation *op,
+			 SlapReply *rs,
+			 a_metaconn_t *mc,
+			 bm_context_t *bc,
+			 int candidate,
+			 int do_lock);
+meta_search_candidate_t
+asyncmeta_back_modify_start(Operation *op,
+			    SlapReply *rs,
+			    a_metaconn_t *mc,
+			    bm_context_t *bc,
+			    int candidate,
+			    int do_lock);
+
+meta_search_candidate_t
+asyncmeta_back_modrdn_start(Operation *op,
+			    SlapReply *rs,
+			    a_metaconn_t *mc,
+			    bm_context_t *bc,
+			    int candidate,
+			    int do_lock);
+meta_search_candidate_t
+asyncmeta_back_delete_start(Operation *op,
+			    SlapReply *rs,
+			    a_metaconn_t *mc,
+			    bm_context_t *bc,
+			    int candidate,
+			    int do_lock);
+
+meta_search_candidate_t
+asyncmeta_back_compare_start(Operation *op,
+			     SlapReply *rs,
+			     a_metaconn_t *mc,
+			     bm_context_t *bc,
+			     int candidate,
+			     int do_lock);
+
+bm_context_t *
+asyncmeta_bc_in_queue(a_metaconn_t *mc,
+		      bm_context_t *bc);
+
+int
+asyncmeta_error_cleanup(Operation *op,
+			SlapReply *rs,
+			bm_context_t *bc,
+			a_metaconn_t *mc,
+			int candidate);
+
+int
+asyncmeta_reset_msc(Operation	*op,
+		    a_metaconn_t	*mc,
+		    int		candidate,
+		    int             unbind,
+		    const char *caller);
+
+
+void
+asyncmeta_back_conn_free(
+	            void 		*v_mc );
+
+void asyncmeta_log_msc(a_metasingleconn_t *msc);
+void asyncmeta_log_conns(a_metainfo_t *mi);
+
+void asyncmeta_get_timestamp(char *buf);
+
+int
+asyncmeta_dncache_update_entry(a_metadncache_t	*cache,
+			       struct berval	*ndn,
+			       int 		target );
+
+void
+asyncmeta_dnattr_result_rewrite(a_dncookie		*dc,
+				BerVarray		a_vals);
+
+void
+asyncmeta_referral_result_rewrite(a_dncookie		*dc,
+				  BerVarray		a_vals);
+
+meta_search_candidate_t
+asyncmeta_send_all_pending_ops(a_metaconn_t *mc,
+			       int          candidate,
+			       void         *ctx,
+			       int          dolock);
+meta_search_candidate_t
+asyncmeta_return_bind_errors(a_metaconn_t *mc,
+			     int          candidate,
+			     SlapReply    *bind_result,
+			     void         *ctx,
+			     int          dolock);
+
+/* The the maximum time in seconds after a result has been received on a connection,
+ * after which it can be reset if a sender error occurs. Should this be configurable? */
+#define META_BACK_RESULT_INTERVAL (2)
+
+extern int asyncmeta_debug;
+
+LDAP_END_DECL
+
+#endif /* SLAPD_ASYNCMETA_H */
diff --git a/servers/slapd/back-asyncmeta/bind.c b/servers/slapd/back-asyncmeta/bind.c
new file mode 100644
index 0000000..e290350
--- /dev/null
+++ b/servers/slapd/back-asyncmeta/bind.c
@@ -0,0 +1,1730 @@
+/* bind.c - bind request handler functions for binding
+ * to remote targets for back-asyncmeta */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016-2022 The OpenLDAP Foundation.
+ * Portions Copyright 2016 Symas Corporation.
+ * 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 developed by Symas Corporation
+ * based on back-meta module for inclusion in OpenLDAP Software.
+ * This work was sponsored by Ericsson. */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/errno.h>
+#include <ac/socket.h>
+#include <ac/string.h>
+#include "slap.h"
+#include "../../../libraries/libldap/ldap-int.h"
+
+#define AVL_INTERNAL
+#include "../back-ldap/back-ldap.h"
+#include "back-asyncmeta.h"
+#include "lutil_ldap.h"
+
+#define LDAP_CONTROL_OBSOLETE_PROXY_AUTHZ	"2.16.840.1.113730.3.4.12"
+
+static int
+asyncmeta_proxy_authz_bind(
+	a_metaconn_t		*mc,
+	int			candidate,
+	Operation		*op,
+	SlapReply		*rs,
+	ldap_back_send_t	sendok,
+	int			dolock );
+
+static int
+asyncmeta_single_bind(
+	Operation		*op,
+	SlapReply		*rs,
+	a_metaconn_t		*mc,
+	int			candidate );
+
+int
+asyncmeta_back_bind( Operation *op, SlapReply *rs )
+{
+	a_metainfo_t	*mi = ( a_metainfo_t * )op->o_bd->be_private;
+	a_metaconn_t	*mc = NULL;
+
+	int		rc = LDAP_OTHER,
+			i,
+			gotit = 0,
+			isroot = 0;
+
+	SlapReply	*candidates;
+
+	candidates = op->o_tmpcalloc(mi->mi_ntargets, sizeof(SlapReply),op->o_tmpmemctx);
+	rs->sr_err = LDAP_SUCCESS;
+
+	Debug( LDAP_DEBUG_ARGS, "%s asyncmeta_back_bind: dn=\"%s\".\n",
+		op->o_log_prefix, op->o_req_dn.bv_val );
+
+	/* the test on the bind method should be superfluous */
+	switch ( be_rootdn_bind( op, rs ) ) {
+	case LDAP_SUCCESS:
+		if ( META_BACK_DEFER_ROOTDN_BIND( mi ) ) {
+			/* frontend will return success */
+			return rs->sr_err;
+		}
+
+		isroot = 1;
+		/* fallthru */
+
+	case SLAP_CB_CONTINUE:
+		break;
+
+	default:
+		/* be_rootdn_bind() sent result */
+		return rs->sr_err;
+	}
+
+	/* we need asyncmeta_getconn() not send result even on error,
+	 * because we want to intercept the error and make it
+	 * invalidCredentials */
+	mc = asyncmeta_getconn( op, rs, candidates, NULL, LDAP_BACK_BIND_DONTSEND, 1 );
+	if ( !mc ) {
+		Debug(LDAP_DEBUG_ANY,
+		      "%s asyncmeta_back_bind: no target " "for dn \"%s\" (%d%s%s).\n",
+		      op->o_log_prefix, op->o_req_dn.bv_val,
+		      rs->sr_err, rs->sr_text ? ". " : "",
+		      rs->sr_text ? rs->sr_text : "" );
+
+		/* FIXME: there might be cases where we don't want
+		 * to map the error onto invalidCredentials */
+		switch ( rs->sr_err ) {
+		case LDAP_NO_SUCH_OBJECT:
+		case LDAP_UNWILLING_TO_PERFORM:
+			rs->sr_err = LDAP_INVALID_CREDENTIALS;
+			rs->sr_text = NULL;
+			break;
+		}
+		send_ldap_result( op, rs );
+		return rs->sr_err;
+	}
+
+	/*
+	 * Each target is scanned ...
+	 */
+	mc->mc_authz_target = META_BOUND_NONE;
+	for ( i = 0; i < mi->mi_ntargets; i++ ) {
+		a_metatarget_t	*mt = mi->mi_targets[ i ];
+		int		lerr;
+
+		/*
+		 * Skip non-candidates
+		 */
+		if ( !META_IS_CANDIDATE( &candidates[ i ] ) ) {
+			continue;
+		}
+
+		if ( gotit == 0 ) {
+			/* set rc to LDAP_SUCCESS only if at least
+			 * one candidate has been tried */
+			rc = LDAP_SUCCESS;
+			gotit = 1;
+
+		} else if ( !isroot ) {
+			/*
+			 * A bind operation is expected to have
+			 * ONE CANDIDATE ONLY!
+			 */
+			Debug( LDAP_DEBUG_ANY,
+				"### %s asyncmeta_back_bind: more than one"
+				" candidate selected...\n",
+				op->o_log_prefix );
+		}
+
+		if ( isroot ) {
+			if ( mt->mt_idassert_authmethod == LDAP_AUTH_NONE
+				|| BER_BVISNULL( &mt->mt_idassert_authcDN ) )
+			{
+				a_metasingleconn_t	*msc = &mc->mc_conns[ i ];
+
+				if ( !BER_BVISNULL( &msc->msc_bound_ndn ) ) {
+					ch_free( msc->msc_bound_ndn.bv_val );
+					BER_BVZERO( &msc->msc_bound_ndn );
+				}
+
+				if ( !BER_BVISNULL( &msc->msc_cred ) ) {
+					/* destroy sensitive data */
+					memset( msc->msc_cred.bv_val, 0,
+						msc->msc_cred.bv_len );
+					ch_free( msc->msc_cred.bv_val );
+					BER_BVZERO( &msc->msc_cred );
+				}
+
+				continue;
+			}
+
+
+			(void)asyncmeta_proxy_authz_bind( mc, i, op, rs, LDAP_BACK_DONTSEND, 1 );
+			lerr = rs->sr_err;
+
+		} else {
+			lerr = asyncmeta_single_bind( op, rs, mc, i );
+		}
+
+		if ( lerr != LDAP_SUCCESS ) {
+			rc = rs->sr_err = lerr;
+
+			/* FIXME: in some cases (e.g. unavailable)
+			 * do not assume it's not candidate; rather
+			 * mark this as an error to be eventually
+			 * reported to client */
+			META_CANDIDATE_CLEAR( &candidates[ i ] );
+			break;
+		}
+	}
+
+	if ( mc != NULL ) {
+		for ( i = 0; i < mi->mi_ntargets; i++ ) {
+			a_metasingleconn_t	*msc = &mc->mc_conns[ i ];
+			if ( !BER_BVISNULL( &msc->msc_bound_ndn ) ) {
+				ch_free( msc->msc_bound_ndn.bv_val );
+			}
+
+			if ( !BER_BVISNULL( &msc->msc_cred ) ) {
+				/* destroy sensitive data */
+				memset( msc->msc_cred.bv_val, 0,
+					msc->msc_cred.bv_len );
+				ch_free( msc->msc_cred.bv_val );
+			}
+		}
+		asyncmeta_back_conn_free( mc );
+	}
+
+	/*
+	 * rc is LDAP_SUCCESS if at least one bind succeeded,
+	 * err is the last error that occurred during a bind;
+	 * if at least (and at most?) one bind succeeds, fine.
+	 */
+	if ( rc != LDAP_SUCCESS ) {
+
+		/*
+		 * deal with bind failure ...
+		 */
+
+		/*
+		 * no target was found within the naming context,
+		 * so bind must fail with invalid credentials
+		 */
+		if ( rs->sr_err == LDAP_SUCCESS && gotit == 0 ) {
+			rs->sr_err = LDAP_INVALID_CREDENTIALS;
+		} else {
+			rs->sr_err = slap_map_api2result( rs );
+		}
+		send_ldap_result( op, rs );
+		return rs->sr_err;
+
+	}
+	return LDAP_SUCCESS;
+}
+
+static int
+asyncmeta_bind_op_result(
+	Operation		*op,
+	SlapReply		*rs,
+	a_metaconn_t		*mc,
+	int			candidate,
+	int			msgid,
+	ldap_back_send_t	sendok,
+	int			dolock )
+{
+	a_metainfo_t		*mi = mc->mc_info;
+	a_metatarget_t		*mt = mi->mi_targets[ candidate ];
+	a_metasingleconn_t	*msc = &mc->mc_conns[ candidate ];
+	LDAPMessage		*res;
+	struct timeval		tv;
+	int			rc;
+	int			nretries = mt->mt_nretries;
+
+	Debug( LDAP_DEBUG_TRACE,
+		">>> %s asyncmeta_bind_op_result[%d]\n",
+		op->o_log_prefix, candidate );
+
+	/* make sure this is clean */
+	assert( rs->sr_ctrls == NULL );
+
+	if ( rs->sr_err == LDAP_SUCCESS ) {
+		time_t		stoptime = (time_t)(-1),
+				timeout;
+		int		timeout_err = op->o_protocol >= LDAP_VERSION3 ?
+				LDAP_ADMINLIMIT_EXCEEDED : LDAP_OTHER;
+		const char	*timeout_text = "Operation timed out";
+		slap_op_t	opidx = slap_req2op( op->o_tag );
+
+		/* since timeout is not specified, compute and use
+		 * the one specific to the ongoing operation */
+		if ( opidx == LDAP_REQ_SEARCH ) {
+			if ( op->ors_tlimit <= 0 ) {
+				timeout = 0;
+
+			} else {
+				timeout = op->ors_tlimit;
+				timeout_err = LDAP_TIMELIMIT_EXCEEDED;
+				timeout_text = NULL;
+			}
+
+		} else {
+			timeout = mt->mt_timeout[ opidx ];
+		}
+
+		/* better than nothing :) */
+		if ( timeout == 0 ) {
+			if ( mi->mi_idle_timeout ) {
+				timeout = mi->mi_idle_timeout;
+
+			}
+		}
+
+		if ( timeout ) {
+			stoptime = op->o_time + timeout;
+		}
+
+		LDAP_BACK_TV_SET( &tv );
+
+		/*
+		 * handle response!!!
+		 */
+retry:;
+		rc = ldap_result( msc->msc_ld, msgid, LDAP_MSG_ALL, &tv, &res );
+		switch ( rc ) {
+		case 0:
+			if ( nretries != META_RETRY_NEVER
+				|| ( timeout && slap_get_time() <= stoptime ) )
+			{
+				ldap_pvt_thread_yield();
+				if ( nretries > 0 ) {
+					nretries--;
+				}
+				tv = mt->mt_bind_timeout;
+				goto retry;
+			}
+
+			/* don't let anyone else use this handler,
+			 * because there's a pending bind that will not
+			 * be acknowledged */
+			assert( LDAP_BACK_CONN_BINDING( msc ) );
+
+#ifdef DEBUG_205
+			Debug( LDAP_DEBUG_ANY, "### %s asyncmeta_bind_op_result ldap_unbind_ext[%d] ld=%p\n",
+				op->o_log_prefix, candidate, (void *)msc->msc_ld );
+#endif /* DEBUG_205 */
+
+			rs->sr_err = timeout_err;
+			rs->sr_text = timeout_text;
+			break;
+
+		case -1:
+			ldap_get_option( msc->msc_ld, LDAP_OPT_ERROR_NUMBER,
+				&rs->sr_err );
+
+			Debug( LDAP_DEBUG_ANY,
+			      "### %s asyncmeta_bind_op_result[%d]: err=%d (%s) nretries=%d.\n",
+			      op->o_log_prefix, candidate, rs->sr_err,
+			      ldap_err2string(rs->sr_err), nretries );
+			break;
+
+		default:
+			/* only touch when activity actually took place... */
+			if ( mi->mi_idle_timeout != 0 && msc->msc_time < op->o_time ) {
+				msc->msc_time = op->o_time;
+			}
+
+			/* FIXME: matched? referrals? response controls? */
+			rc = ldap_parse_result( msc->msc_ld, res, &rs->sr_err,
+					NULL, NULL, NULL, NULL, 1 );
+			if ( rc != LDAP_SUCCESS ) {
+				rs->sr_err = rc;
+			}
+			rs->sr_err = slap_map_api2result( rs );
+			break;
+		}
+	}
+
+	rs->sr_err = slap_map_api2result( rs );
+	Debug( LDAP_DEBUG_TRACE,
+		"<<< %s asyncmeta_bind_op_result[%d] err=%d\n",
+		op->o_log_prefix, candidate, rs->sr_err );
+
+	return rs->sr_err;
+}
+
+/*
+ * asyncmeta_single_bind
+ *
+ * attempts to perform a bind with creds
+ */
+static int
+asyncmeta_single_bind(
+	Operation		*op,
+	SlapReply		*rs,
+	a_metaconn_t		*mc,
+	int			candidate )
+{
+	a_metainfo_t		*mi = mc->mc_info;
+	a_metatarget_t		*mt = mi->mi_targets[ candidate ];
+	struct berval		mdn = BER_BVNULL;
+	a_metasingleconn_t	*msc = &mc->mc_conns[ candidate ];
+	int			msgid;
+	a_dncookie		dc;
+	struct berval		save_o_dn;
+	int			save_o_do_not_cache;
+	LDAPControl		**ctrls = NULL;
+
+	if ( !BER_BVISNULL( &msc->msc_bound_ndn ) ) {
+		ch_free( msc->msc_bound_ndn.bv_val );
+		BER_BVZERO( &msc->msc_bound_ndn );
+	}
+
+	if ( !BER_BVISNULL( &msc->msc_cred ) ) {
+		/* destroy sensitive data */
+		memset( msc->msc_cred.bv_val, 0, msc->msc_cred.bv_len );
+		ch_free( msc->msc_cred.bv_val );
+		BER_BVZERO( &msc->msc_cred );
+	}
+
+	/*
+	 * Rewrite the bind dn if needed
+	 */
+	dc.op = op;
+	dc.target = mt;
+	dc.memctx = op->o_tmpmemctx;
+	dc.to_from = MASSAGE_REQ;
+
+	asyncmeta_dn_massage( &dc, &op->o_req_dn, &mdn );
+
+	/* don't add proxyAuthz; set the bindDN */
+	save_o_dn = op->o_dn;
+	save_o_do_not_cache = op->o_do_not_cache;
+	op->o_do_not_cache = 1;
+	op->o_dn = op->o_req_dn;
+
+	ctrls = op->o_ctrls;
+	rs->sr_err = asyncmeta_controls_add( op, rs, mc, candidate, be_isroot(op), &ctrls );
+	op->o_dn = save_o_dn;
+	op->o_do_not_cache = save_o_do_not_cache;
+	if ( rs->sr_err != LDAP_SUCCESS ) {
+		goto return_results;
+	}
+
+	/* FIXME: this fixes the bind problem right now; we need
+	 * to use the asynchronous version to get the "matched"
+	 * and more in case of failure ... */
+	/* FIXME: should we check if at least some of the op->o_ctrls
+	 * can/should be passed? */
+	for (;;) {
+		rs->sr_err = ldap_sasl_bind( msc->msc_ld, mdn.bv_val,
+			LDAP_SASL_SIMPLE, &op->orb_cred,
+			ctrls, NULL, &msgid );
+		if ( rs->sr_err != LDAP_X_CONNECTING ) {
+			break;
+		}
+		ldap_pvt_thread_yield();
+	}
+
+	mi->mi_ldap_extra->controls_free( op, rs, &ctrls );
+
+	asyncmeta_bind_op_result( op, rs, mc, candidate, msgid, LDAP_BACK_DONTSEND, 1 );
+	if ( rs->sr_err != LDAP_SUCCESS ) {
+		goto return_results;
+	}
+
+	/* If defined, proxyAuthz will be used also when
+	 * back-ldap is the authorizing backend; for this
+	 * purpose, a successful bind is followed by a
+	 * bind with the configured identity assertion */
+	/* NOTE: use with care */
+	if ( mt->mt_idassert_flags & LDAP_BACK_AUTH_OVERRIDE ) {
+		asyncmeta_proxy_authz_bind( mc, candidate, op, rs, LDAP_BACK_SENDERR, 1 );
+		if ( !LDAP_BACK_CONN_ISBOUND( msc ) ) {
+			goto return_results;
+		}
+		goto cache_refresh;
+	}
+
+	ber_bvreplace( &msc->msc_bound_ndn, &op->o_req_ndn );
+	LDAP_BACK_CONN_ISBOUND_SET( msc );
+	mc->mc_authz_target = candidate;
+
+	if ( META_BACK_TGT_SAVECRED( mt ) ) {
+		if ( !BER_BVISNULL( &msc->msc_cred ) ) {
+			memset( msc->msc_cred.bv_val, 0,
+				msc->msc_cred.bv_len );
+		}
+		ber_bvreplace( &msc->msc_cred, &op->orb_cred );
+		ldap_set_rebind_proc( msc->msc_ld, mt->mt_rebind_f, msc );
+	}
+
+cache_refresh:;
+	if ( mi->mi_cache.ttl != META_DNCACHE_DISABLED
+			&& !BER_BVISEMPTY( &op->o_req_ndn ) )
+	{
+		( void )asyncmeta_dncache_update_entry( &mi->mi_cache,
+				&op->o_req_ndn, candidate );
+	}
+
+return_results:;
+	if ( mdn.bv_val != op->o_req_dn.bv_val ) {
+		op->o_tmpfree( mdn.bv_val, op->o_tmpmemctx );
+	}
+
+	if ( META_BACK_TGT_QUARANTINE( mt ) ) {
+		asyncmeta_quarantine( op, mi, rs, candidate );
+	}
+	ldap_unbind_ext( msc->msc_ld, NULL, NULL );
+	msc->msc_ld = NULL;
+	ldap_ld_free( msc->msc_ldr, 0, NULL, NULL );
+	msc->msc_ldr = NULL;
+	return rs->sr_err;
+}
+
+
+/*
+ * asyncmeta_back_default_rebind
+ *
+ * This is a callback used for chasing referrals using the same
+ * credentials as the original user on this session.
+ */
+int
+asyncmeta_back_default_rebind(
+	LDAP			*ld,
+	LDAP_CONST char		*url,
+	ber_tag_t		request,
+	ber_int_t		msgid,
+	void			*params )
+{
+	a_metasingleconn_t	*msc = ( a_metasingleconn_t * )params;
+
+	return ldap_sasl_bind_s( ld, msc->msc_bound_ndn.bv_val,
+			LDAP_SASL_SIMPLE, &msc->msc_cred,
+			NULL, NULL, NULL );
+}
+
+/*
+ * meta_back_default_urllist
+ *
+ * This is a callback used for mucking with the urllist
+ */
+int
+asyncmeta_back_default_urllist(
+	LDAP		*ld,
+	LDAPURLDesc	**urllist,
+	LDAPURLDesc	**url,
+	void		*params )
+{
+	a_metatarget_t	*mt = (a_metatarget_t *)params;
+	LDAPURLDesc	**urltail;
+
+	if ( urllist == url ) {
+		return LDAP_SUCCESS;
+	}
+
+	for ( urltail = &(*url)->lud_next; *urltail; urltail = &(*urltail)->lud_next )
+		/* count */ ;
+
+	*urltail = *urllist;
+	*urllist = *url;
+	*url = NULL;
+
+	ldap_pvt_thread_mutex_lock( &mt->mt_uri_mutex );
+	if ( mt->mt_uri ) {
+		ch_free( mt->mt_uri );
+	}
+
+	ldap_get_option( ld, LDAP_OPT_URI, (void *)&mt->mt_uri );
+	ldap_pvt_thread_mutex_unlock( &mt->mt_uri_mutex );
+
+	return LDAP_SUCCESS;
+}
+
+int
+asyncmeta_back_cancel(
+	a_metaconn_t		*mc,
+	Operation		*op,
+	ber_int_t		msgid,
+	int			candidate )
+{
+
+	a_metainfo_t		*mi = mc->mc_info;
+	a_metatarget_t		*mt = mi->mi_targets[ candidate ];
+	a_metasingleconn_t	*msc = &mc->mc_conns[ candidate ];
+
+	int			rc = LDAP_OTHER;
+	struct timeval tv = { 0, 0 };
+	ber_socket_t s;
+
+	Debug( LDAP_DEBUG_TRACE, ">>> %s asyncmeta_back_cancel[%d] msgid=%d\n",
+		op->o_log_prefix, candidate, msgid );
+
+	if (!( LDAP_BACK_CONN_ISBOUND( msc )
+	       || LDAP_BACK_CONN_ISANON( msc )) || msc->msc_ld == NULL ) {
+		Debug( LDAP_DEBUG_TRACE, ">>> %s asyncmeta_back_cancel[%d] msgid=%d\n already reset",
+		op->o_log_prefix, candidate, msgid );
+		return LDAP_SUCCESS;
+	}
+
+	ldap_get_option( msc->msc_ld, LDAP_OPT_DESC, &s );
+	if (s < 0) {
+		return rc;
+	}
+	rc = ldap_int_poll( msc->msc_ld, s, &tv, 1);
+	if (rc < 0) {
+		rc = LDAP_SERVER_DOWN;
+		return rc;
+	}
+	/* default behavior */
+	if ( META_BACK_TGT_ABANDON( mt ) ) {
+		rc = ldap_abandon_ext( msc->msc_ld, msgid, NULL, NULL );
+
+	} else if ( META_BACK_TGT_IGNORE( mt ) ) {
+		rc = ldap_pvt_discard( msc->msc_ld, msgid );
+
+	} else if ( META_BACK_TGT_CANCEL( mt ) ) {
+		rc = ldap_cancel_s( msc->msc_ld, msgid, NULL, NULL );
+
+	} else {
+		assert( 0 );
+	}
+
+	Debug( LDAP_DEBUG_TRACE, "<<< %s asyncmeta_back_cancel[%d] err=%d\n",
+		op->o_log_prefix, candidate, rc );
+
+	return rc;
+}
+
+
+
+/*
+ * asyncmeta_back_proxy_authz_cred()
+ *
+ * prepares credentials & method for meta_back_proxy_authz_bind();
+ * or, if method is SASL, performs the SASL bind directly.
+ */
+int
+asyncmeta_back_proxy_authz_cred(
+	a_metaconn_t		*mc,
+	int			candidate,
+	Operation		*op,
+	SlapReply		*rs,
+	ldap_back_send_t	sendok,
+	struct berval		*binddn,
+	struct berval		*bindcred,
+	int			*method )
+{
+	a_metainfo_t		*mi = mc->mc_info;
+	a_metatarget_t		*mt = mi->mi_targets[ candidate ];
+	a_metasingleconn_t	*msc = &mc->mc_conns[ candidate ];
+	struct berval		ndn;
+	int			dobind = 0;
+	struct timeval old_tv = {0, 0};
+	struct timeval bind_tv = { mt->mt_timeout[ SLAP_OP_BIND ], 0};
+	/* don't proxyAuthz if protocol is not LDAPv3 */
+	switch ( mt->mt_version ) {
+	case LDAP_VERSION3:
+		break;
+
+	case 0:
+		if ( op->o_protocol == 0 || op->o_protocol == LDAP_VERSION3 ) {
+			break;
+		}
+		/* fall thru */
+
+	default:
+		rs->sr_err = LDAP_UNWILLING_TO_PERFORM;
+		if ( sendok & LDAP_BACK_SENDERR ) {
+			send_ldap_result( op, rs );
+		}
+		LDAP_BACK_CONN_ISBOUND_CLEAR( msc );
+		goto done;
+	}
+
+	if ( op->o_tag == LDAP_REQ_BIND ) {
+		ndn = op->o_req_ndn;
+
+	} else if ( !BER_BVISNULL( &op->o_conn->c_ndn ) ) {
+		ndn = op->o_conn->c_ndn;
+
+	} else {
+		ndn = op->o_ndn;
+	}
+	rs->sr_err = LDAP_SUCCESS;
+
+	/*
+	 * FIXME: we need to let clients use proxyAuthz
+	 * otherwise we cannot do symmetric pools of servers;
+	 * we have to live with the fact that a user can
+	 * authorize itself as any ID that is allowed
+	 * by the authzTo directive of the "proxyauthzdn".
+	 */
+	/*
+	 * NOTE: current Proxy Authorization specification
+	 * and implementation do not allow proxy authorization
+	 * control to be provided with Bind requests
+	 */
+	/*
+	 * if no bind took place yet, but the connection is bound
+	 * and the "proxyauthzdn" is set, then bind as
+	 * "proxyauthzdn" and explicitly add the proxyAuthz
+	 * control to every operation with the dn bound
+	 * to the connection as control value.
+	 */
+
+	/* bind as proxyauthzdn only if no idassert mode
+	 * is requested, or if the client's identity
+	 * is authorized */
+	switch ( mt->mt_idassert_mode ) {
+	case LDAP_BACK_IDASSERT_LEGACY:
+		if ( !BER_BVISNULL( &ndn ) && !BER_BVISEMPTY( &ndn ) ) {
+			if ( !BER_BVISNULL( &mt->mt_idassert_authcDN ) && !BER_BVISEMPTY( &mt->mt_idassert_authcDN ) )
+			{
+				*binddn = mt->mt_idassert_authcDN;
+				*bindcred = mt->mt_idassert_passwd;
+				dobind = 1;
+			}
+		}
+		break;
+
+	default:
+		/* NOTE: rootdn can always idassert */
+		if ( BER_BVISNULL( &ndn )
+			&& mt->mt_idassert_authz == NULL
+			&& !( mt->mt_idassert_flags & LDAP_BACK_AUTH_AUTHZ_ALL ) )
+		{
+			if ( mt->mt_idassert_flags & LDAP_BACK_AUTH_PRESCRIPTIVE ) {
+				rs->sr_err = LDAP_INAPPROPRIATE_AUTH;
+				if ( sendok & LDAP_BACK_SENDERR ) {
+					send_ldap_result( op, rs );
+				}
+				LDAP_BACK_CONN_ISBOUND_CLEAR( msc );
+				goto done;
+
+			}
+
+			rs->sr_err = LDAP_SUCCESS;
+			*binddn = slap_empty_bv;
+			*bindcred = slap_empty_bv;
+			break;
+
+		} else if ( mt->mt_idassert_authz && !be_isroot( op ) ) {
+			struct berval authcDN;
+
+			if ( BER_BVISNULL( &ndn ) ) {
+				authcDN = slap_empty_bv;
+
+			} else {
+				authcDN = ndn;
+			}
+			rs->sr_err = slap_sasl_matches( op, mt->mt_idassert_authz,
+					&authcDN, &authcDN );
+			if ( rs->sr_err != LDAP_SUCCESS ) {
+				if ( mt->mt_idassert_flags & LDAP_BACK_AUTH_PRESCRIPTIVE ) {
+					if ( sendok & LDAP_BACK_SENDERR ) {
+						send_ldap_result( op, rs );
+					}
+					LDAP_BACK_CONN_ISBOUND_CLEAR( msc );
+					goto done;
+				}
+
+				rs->sr_err = LDAP_SUCCESS;
+				*binddn = slap_empty_bv;
+				*bindcred = slap_empty_bv;
+				break;
+			}
+		}
+
+		*binddn = mt->mt_idassert_authcDN;
+		*bindcred = mt->mt_idassert_passwd;
+		dobind = 1;
+		break;
+	}
+
+	if ( dobind && mt->mt_idassert_authmethod == LDAP_AUTH_SASL ) {
+#ifdef HAVE_CYRUS_SASL
+		void		*defaults = NULL;
+		struct berval	authzID = BER_BVNULL;
+		int		freeauthz = 0;
+
+		/* if SASL supports native authz, prepare for it */
+		if ( ( !op->o_do_not_cache || !op->o_is_auth_check ) &&
+				( mt->mt_idassert_flags & LDAP_BACK_AUTH_NATIVE_AUTHZ ) )
+		{
+			switch ( mt->mt_idassert_mode ) {
+			case LDAP_BACK_IDASSERT_OTHERID:
+			case LDAP_BACK_IDASSERT_OTHERDN:
+				authzID = mt->mt_idassert_authzID;
+				break;
+
+			case LDAP_BACK_IDASSERT_ANONYMOUS:
+				BER_BVSTR( &authzID, "dn:" );
+				break;
+
+			case LDAP_BACK_IDASSERT_SELF:
+				if ( BER_BVISNULL( &ndn ) ) {
+					/* connection is not authc'd, so don't idassert */
+					BER_BVSTR( &authzID, "dn:" );
+					break;
+				}
+				authzID.bv_len = STRLENOF( "dn:" ) + ndn.bv_len;
+				authzID.bv_val = slap_sl_malloc( authzID.bv_len + 1, op->o_tmpmemctx );
+				AC_MEMCPY( authzID.bv_val, "dn:", STRLENOF( "dn:" ) );
+				AC_MEMCPY( authzID.bv_val + STRLENOF( "dn:" ),
+						ndn.bv_val, ndn.bv_len + 1 );
+				freeauthz = 1;
+				break;
+
+			default:
+				break;
+			}
+		}
+
+		if ( mt->mt_idassert_secprops != NULL ) {
+			rs->sr_err = ldap_set_option( msc->msc_ld,
+				LDAP_OPT_X_SASL_SECPROPS,
+				(void *)mt->mt_idassert_secprops );
+
+			if ( rs->sr_err != LDAP_OPT_SUCCESS ) {
+				rs->sr_err = LDAP_OTHER;
+				if ( sendok & LDAP_BACK_SENDERR ) {
+					send_ldap_result( op, rs );
+				}
+				LDAP_BACK_CONN_ISBOUND_CLEAR( msc );
+				goto done;
+			}
+		}
+
+		ldap_get_option( msc->msc_ld, LDAP_OPT_TIMEOUT, (void *)&old_tv);
+
+		if (mt->mt_timeout[ SLAP_OP_BIND ] > 0 ) {
+			rs->sr_err = ldap_set_option( msc->msc_ld,
+				LDAP_OPT_TIMEOUT,
+				(void *)&bind_tv );
+
+			if ( rs->sr_err != LDAP_OPT_SUCCESS ) {
+				rs->sr_err = LDAP_OTHER;
+				if ( sendok & LDAP_BACK_SENDERR ) {
+					send_ldap_result( op, rs );
+				}
+				LDAP_BACK_CONN_ISBOUND_CLEAR( msc );
+				goto done;
+			}
+		}
+		defaults = lutil_sasl_defaults( msc->msc_ld,
+				mt->mt_idassert_sasl_mech.bv_val,
+				mt->mt_idassert_sasl_realm.bv_val,
+				mt->mt_idassert_authcID.bv_val,
+				mt->mt_idassert_passwd.bv_val,
+				authzID.bv_val );
+		if ( defaults == NULL ) {
+			rs->sr_err = LDAP_OTHER;
+			LDAP_BACK_CONN_ISBOUND_CLEAR( msc );
+			if ( sendok & LDAP_BACK_SENDERR ) {
+				send_ldap_result( op, rs );
+			}
+			goto done;
+		}
+
+		rs->sr_err = ldap_sasl_interactive_bind_s( msc->msc_ld, binddn->bv_val,
+				mt->mt_idassert_sasl_mech.bv_val, NULL, NULL,
+				LDAP_SASL_QUIET, lutil_sasl_interact,
+				defaults );
+
+		/* restore the old timeout just in case */
+		ldap_set_option( msc->msc_ld, LDAP_OPT_TIMEOUT, (void *)&old_tv );
+
+		rs->sr_err = slap_map_api2result( rs );
+		if ( rs->sr_err != LDAP_SUCCESS ) {
+			if ( LogTest( asyncmeta_debug ) ) {
+				char	time_buf[ SLAP_TEXT_BUFLEN ];
+				asyncmeta_get_timestamp(time_buf);
+				Debug( asyncmeta_debug, "[%s] asyncmeta_back_proxy_authz_cred failed bind msc: %p\n",
+				      time_buf, msc );
+			}
+			LDAP_BACK_CONN_ISBOUND_CLEAR( msc );
+			if ( sendok & LDAP_BACK_SENDERR ) {
+				send_ldap_result( op, rs );
+			}
+
+		} else {
+			LDAP_BACK_CONN_ISBOUND_SET( msc );
+		}
+
+		lutil_sasl_freedefs( defaults );
+		if ( freeauthz ) {
+			slap_sl_free( authzID.bv_val, op->o_tmpmemctx );
+		}
+
+		goto done;
+#endif /* HAVE_CYRUS_SASL */
+	}
+
+	*method = mt->mt_idassert_authmethod;
+	switch ( mt->mt_idassert_authmethod ) {
+	case LDAP_AUTH_NONE:
+		BER_BVSTR( binddn, "" );
+		BER_BVSTR( bindcred, "" );
+		/* fallthru */
+
+	case LDAP_AUTH_SIMPLE:
+		break;
+
+	default:
+		/* unsupported! */
+		LDAP_BACK_CONN_ISBOUND_CLEAR( msc );
+		rs->sr_err = LDAP_AUTH_METHOD_NOT_SUPPORTED;
+		if ( sendok & LDAP_BACK_SENDERR ) {
+			send_ldap_result( op, rs );
+		}
+		break;
+	}
+
+done:;
+
+	if ( !BER_BVISEMPTY( binddn ) ) {
+		LDAP_BACK_CONN_ISIDASSERT_SET( msc );
+	}
+
+	return rs->sr_err;
+}
+
+static int
+asyncmeta_proxy_authz_bind(
+	a_metaconn_t *mc,
+	int candidate,
+	Operation *op,
+	SlapReply *rs,
+	ldap_back_send_t sendok,
+	int dolock )
+{
+	a_metainfo_t		*mi = mc->mc_info;
+	a_metatarget_t		*mt = mi->mi_targets[ candidate ];
+	a_metasingleconn_t	*msc = &mc->mc_conns[ candidate ];
+	struct berval		binddn = BER_BVC( "" ),
+				cred = BER_BVC( "" );
+	int			method = LDAP_AUTH_NONE,
+				rc;
+
+	rc = asyncmeta_back_proxy_authz_cred( mc, candidate, op, rs, sendok, &binddn, &cred, &method );
+	if ( rc == LDAP_SUCCESS && !LDAP_BACK_CONN_ISBOUND( msc ) ) {
+		int	msgid;
+
+		switch ( method ) {
+		case LDAP_AUTH_NONE:
+		case LDAP_AUTH_SIMPLE:
+			for (;;) {
+				rs->sr_err = ldap_sasl_bind( msc->msc_ld,
+					binddn.bv_val, LDAP_SASL_SIMPLE,
+					&cred, NULL, NULL, &msgid );
+				if ( rs->sr_err != LDAP_X_CONNECTING ) {
+					break;
+				}
+				ldap_pvt_thread_yield();
+			}
+
+			rc = asyncmeta_bind_op_result( op, rs, mc, candidate, msgid, sendok, dolock );
+			if ( rc == LDAP_SUCCESS ) {
+				/* set rebind stuff in case of successful proxyAuthz bind,
+				 * so that referral chasing is attempted using the right
+				 * identity */
+				LDAP_BACK_CONN_ISBOUND_SET( msc );
+				ber_bvreplace( &msc->msc_bound_ndn, &binddn );
+
+				if ( META_BACK_TGT_SAVECRED( mt ) ) {
+					if ( !BER_BVISNULL( &msc->msc_cred ) ) {
+						memset( msc->msc_cred.bv_val, 0,
+							msc->msc_cred.bv_len );
+					}
+					ber_bvreplace( &msc->msc_cred, &cred );
+					ldap_set_rebind_proc( msc->msc_ld, mt->mt_rebind_f, msc );
+				}
+			}
+			break;
+
+		default:
+			assert( 0 );
+			break;
+		}
+	}
+
+	return LDAP_BACK_CONN_ISBOUND( msc );
+}
+
+
+static int
+asyncmeta_back_proxy_authz_ctrl(Operation *op,
+				SlapReply *rs,
+				struct berval	*bound_ndn,
+				int		version,
+				int             isroot,
+				slap_idassert_t	*si,
+				LDAPControl	*ctrl )
+{
+	slap_idassert_mode_t	mode;
+	struct berval		assertedID,
+				ndn;
+
+	rs->sr_err = SLAP_CB_CONTINUE;
+
+	/* FIXME: SASL/EXTERNAL over ldapi:// doesn't honor the authcID,
+	 * but if it is not set this test fails.  We need a different
+	 * means to detect if idassert is enabled */
+	if ( ( BER_BVISNULL( &si->si_bc.sb_authcId ) || BER_BVISEMPTY( &si->si_bc.sb_authcId ) )
+		&& ( BER_BVISNULL( &si->si_bc.sb_binddn ) || BER_BVISEMPTY( &si->si_bc.sb_binddn ) )
+		&& BER_BVISNULL( &si->si_bc.sb_saslmech ) )
+	{
+		goto done;
+	}
+
+	if ( !op->o_conn || op->o_do_not_cache || ( isroot ) ) {
+		goto done;
+	}
+
+	if ( op->o_tag == LDAP_REQ_BIND ) {
+		ndn = op->o_req_ndn;
+
+#if 0
+	} else if ( !BER_BVISNULL( &op->o_conn->c_ndn ) ) {
+		ndn = op->o_conn->c_ndn;
+#endif
+	} else {
+		ndn = op->o_ndn;
+	}
+
+	if ( si->si_mode == LDAP_BACK_IDASSERT_LEGACY ) {
+		if ( op->o_proxy_authz ) {
+			/*
+			 * FIXME: we do not want to perform proxyAuthz
+			 * on behalf of the client, because this would
+			 * be performed with "proxyauthzdn" privileges.
+			 *
+			 * This might actually be too strict, since
+			 * the "proxyauthzdn" authzTo, and each entry's
+			 * authzFrom attributes may be crafted
+			 * to avoid unwanted proxyAuthz to take place.
+			 */
+#if 0
+			rs->sr_err = LDAP_UNWILLING_TO_PERFORM;
+			rs->sr_text = "proxyAuthz not allowed within namingContext";
+#endif
+			goto done;
+		}
+
+		if ( !BER_BVISNULL( bound_ndn ) ) {
+			goto done;
+		}
+
+		if ( BER_BVISNULL( &ndn ) ) {
+			goto done;
+		}
+
+		if ( BER_BVISNULL( &si->si_bc.sb_binddn ) ) {
+			goto done;
+		}
+
+	} else if ( si->si_bc.sb_method == LDAP_AUTH_SASL ) {
+		if ( ( si->si_flags & LDAP_BACK_AUTH_NATIVE_AUTHZ ) )
+		{
+			/* already asserted in SASL via native authz */
+			goto done;
+		}
+
+	} else if ( si->si_authz && !isroot ) {
+		int		rc;
+		struct berval authcDN;
+
+		if ( BER_BVISNULL( &ndn ) ) {
+			authcDN = slap_empty_bv;
+		} else {
+			authcDN = ndn;
+		}
+		rc = slap_sasl_matches( op, si->si_authz,
+				&authcDN, &authcDN );
+		if ( rc != LDAP_SUCCESS ) {
+			if ( si->si_flags & LDAP_BACK_AUTH_PRESCRIPTIVE ) {
+				/* ndn is not authorized
+				 * to use idassert */
+				rs->sr_err = rc;
+			}
+			goto done;
+		}
+	}
+
+	if ( op->o_proxy_authz ) {
+		/*
+		 * FIXME: we can:
+		 * 1) ignore the already set proxyAuthz control
+		 * 2) leave it in place, and don't set ours
+		 * 3) add both
+		 * 4) reject the operation
+		 *
+		 * option (4) is very drastic
+		 * option (3) will make the remote server reject
+		 * the operation, thus being equivalent to (4)
+		 * option (2) will likely break the idassert
+		 * assumptions, so we cannot accept it;
+		 * option (1) means that we are contradicting
+		 * the client's request.
+		 *
+		 * I think (4) is the only correct choice.
+		 */
+		rs->sr_err = LDAP_UNWILLING_TO_PERFORM;
+		rs->sr_text = "proxyAuthz not allowed within namingContext";
+	}
+
+	if ( op->o_is_auth_check ) {
+		mode = LDAP_BACK_IDASSERT_NOASSERT;
+
+	} else {
+		mode = si->si_mode;
+	}
+
+	switch ( mode ) {
+	case LDAP_BACK_IDASSERT_LEGACY:
+		/* original behavior:
+		 * assert the client's identity */
+	case LDAP_BACK_IDASSERT_SELF:
+		assertedID = ndn;
+		break;
+
+	case LDAP_BACK_IDASSERT_ANONYMOUS:
+		/* assert "anonymous" */
+		assertedID = slap_empty_bv;
+		break;
+
+	case LDAP_BACK_IDASSERT_NOASSERT:
+		/* don't assert; bind as proxyauthzdn */
+		goto done;
+
+	case LDAP_BACK_IDASSERT_OTHERID:
+	case LDAP_BACK_IDASSERT_OTHERDN:
+		/* assert idassert DN */
+		assertedID = si->si_bc.sb_authzId;
+		break;
+
+	default:
+		assert( 0 );
+	}
+
+	/* if we got here, "" is allowed to proxyAuthz */
+	if ( BER_BVISNULL( &assertedID ) ) {
+		assertedID = slap_empty_bv;
+	}
+
+	/* don't idassert the bound DN (ITS#4497) */
+	if ( dn_match( &assertedID, bound_ndn ) ) {
+		goto done;
+	}
+
+	ctrl->ldctl_oid = LDAP_CONTROL_PROXY_AUTHZ;
+	ctrl->ldctl_iscritical = ( ( si->si_flags & LDAP_BACK_AUTH_PROXYAUTHZ_CRITICAL ) == LDAP_BACK_AUTH_PROXYAUTHZ_CRITICAL );
+
+	switch ( si->si_mode ) {
+	/* already in u:ID or dn:DN form */
+	case LDAP_BACK_IDASSERT_OTHERID:
+	case LDAP_BACK_IDASSERT_OTHERDN:
+		ber_dupbv_x( &ctrl->ldctl_value, &assertedID, op->o_tmpmemctx );
+		rs->sr_err = LDAP_SUCCESS;
+		break;
+
+	/* needs the dn: prefix */
+	default:
+		ctrl->ldctl_value.bv_len = assertedID.bv_len + STRLENOF( "dn:" );
+		ctrl->ldctl_value.bv_val = op->o_tmpalloc( ctrl->ldctl_value.bv_len + 1,
+				op->o_tmpmemctx );
+		AC_MEMCPY( ctrl->ldctl_value.bv_val, "dn:", STRLENOF( "dn:" ) );
+		AC_MEMCPY( &ctrl->ldctl_value.bv_val[ STRLENOF( "dn:" ) ],
+				assertedID.bv_val, assertedID.bv_len + 1 );
+		rs->sr_err = LDAP_SUCCESS;
+		break;
+	}
+
+	/* Older versions of <draft-weltman-ldapv3-proxy> required
+	 * to encode the value of the authzID (and called it proxyDN);
+	 * this hack provides compatibility with those DSAs that
+	 * implement it this way */
+	if ( si->si_flags & LDAP_BACK_AUTH_OBSOLETE_ENCODING_WORKAROUND ) {
+		struct berval		authzID = ctrl->ldctl_value;
+		BerElementBuffer	berbuf;
+		BerElement		*ber = (BerElement *)&berbuf;
+		ber_tag_t		tag;
+
+		ber_init2( ber, 0, LBER_USE_DER );
+		ber_set_option( ber, LBER_OPT_BER_MEMCTX, &op->o_tmpmemctx );
+
+		tag = ber_printf( ber, "O", &authzID );
+		if ( tag == LBER_ERROR ) {
+			rs->sr_err = LDAP_OTHER;
+			goto free_ber;
+		}
+
+		if ( ber_flatten2( ber, &ctrl->ldctl_value, 1 ) == -1 ) {
+			rs->sr_err = LDAP_OTHER;
+			goto free_ber;
+		}
+
+		rs->sr_err = LDAP_SUCCESS;
+
+free_ber:;
+		op->o_tmpfree( authzID.bv_val, op->o_tmpmemctx );
+		ber_free_buf( ber );
+
+		if ( rs->sr_err != LDAP_SUCCESS ) {
+			goto done;
+		}
+
+	} else if ( si->si_flags & LDAP_BACK_AUTH_OBSOLETE_PROXY_AUTHZ ) {
+		struct berval		authzID = ctrl->ldctl_value,
+					tmp;
+		BerElementBuffer	berbuf;
+		BerElement		*ber = (BerElement *)&berbuf;
+		ber_tag_t		tag;
+
+		if ( strncasecmp( authzID.bv_val, "dn:", STRLENOF( "dn:" ) ) != 0 ) {
+			rs->sr_err = LDAP_PROTOCOL_ERROR;
+			goto done;
+		}
+
+		tmp = authzID;
+		tmp.bv_val += STRLENOF( "dn:" );
+		tmp.bv_len -= STRLENOF( "dn:" );
+
+		ber_init2( ber, 0, LBER_USE_DER );
+		ber_set_option( ber, LBER_OPT_BER_MEMCTX, &op->o_tmpmemctx );
+
+		/* apparently, Mozilla API encodes this
+		 * as "SEQUENCE { LDAPDN }" */
+		tag = ber_printf( ber, "{O}", &tmp );
+		if ( tag == LBER_ERROR ) {
+			rs->sr_err = LDAP_OTHER;
+			goto free_ber2;
+		}
+
+		if ( ber_flatten2( ber, &ctrl->ldctl_value, 1 ) == -1 ) {
+			rs->sr_err = LDAP_OTHER;
+			goto free_ber2;
+		}
+
+		ctrl->ldctl_oid = LDAP_CONTROL_OBSOLETE_PROXY_AUTHZ;
+		rs->sr_err = LDAP_SUCCESS;
+
+free_ber2:;
+		op->o_tmpfree( authzID.bv_val, op->o_tmpmemctx );
+		ber_free_buf( ber );
+
+		if ( rs->sr_err != LDAP_SUCCESS ) {
+			goto done;
+		}
+	}
+
+done:;
+
+	return rs->sr_err;
+}
+
+/*
+ * Add controls;
+ *
+ * if any needs to be added, it is prepended to existing ones,
+ * in a newly allocated array.  The companion function
+ * mi->mi_ldap_extra->controls_free() must be used to restore the original
+ * status of op->o_ctrls.
+ */
+int
+asyncmeta_controls_add( Operation *op,
+			SlapReply *rs,
+			a_metaconn_t	*mc,
+			int		candidate,
+			int             isroot,
+			LDAPControl	***pctrls )
+{
+	a_metainfo_t		*mi = mc->mc_info;
+	a_metatarget_t		*mt = mi->mi_targets[ candidate ];
+	a_metasingleconn_t	*msc = &mc->mc_conns[ candidate ];
+
+	LDAPControl		**ctrls = NULL;
+	/* set to the maximum number of controls this backend can add */
+	LDAPControl		c[ 2 ] = {{ 0 }};
+	int			n = 0, i, j1 = 0, j2 = 0, skipped = 0;
+
+	*pctrls = NULL;
+
+	rs->sr_err = LDAP_SUCCESS;
+
+	/* don't add controls if protocol is not LDAPv3 */
+	switch ( mt->mt_version ) {
+	case LDAP_VERSION3:
+		break;
+
+	case 0:
+		if ( op->o_protocol == 0 || op->o_protocol == LDAP_VERSION3 ) {
+			break;
+		}
+		/* fall thru */
+
+	default:
+		goto done;
+	}
+
+	/* put controls that go __before__ existing ones here */
+
+	/* proxyAuthz for identity assertion */
+	switch ( asyncmeta_back_proxy_authz_ctrl( op, rs, &msc->msc_bound_ndn,
+					     mt->mt_version, isroot, &mt->mt_idassert, &c[ j1 ] ) )
+	{
+	case SLAP_CB_CONTINUE:
+		break;
+
+	case LDAP_SUCCESS:
+		j1++;
+		break;
+
+	default:
+		goto done;
+	}
+
+	/* put controls that go __after__ existing ones here */
+
+#ifdef SLAP_CONTROL_X_SESSION_TRACKING
+	/* session tracking */
+	if ( META_BACK_TGT_ST_REQUEST( mt ) ) {
+		switch ( slap_ctrl_session_tracking_request_add( op, rs, &c[ j1 + j2 ] ) ) {
+		case SLAP_CB_CONTINUE:
+			break;
+
+		case LDAP_SUCCESS:
+			j2++;
+			break;
+
+		default:
+			goto done;
+		}
+	}
+#endif /* SLAP_CONTROL_X_SESSION_TRACKING */
+
+	if ( rs->sr_err == SLAP_CB_CONTINUE ) {
+		rs->sr_err = LDAP_SUCCESS;
+	}
+
+	/* if nothing to do, just bail out */
+	if ( j1 == 0 && j2 == 0 ) {
+		goto done;
+	}
+
+	assert( j1 + j2 <= (int) (sizeof( c )/sizeof( c[0] )) );
+
+	if ( op->o_ctrls ) {
+		for ( n = 0; op->o_ctrls[ n ]; n++ )
+			/* just count ctrls */ ;
+	}
+
+	ctrls = op->o_tmpalloc( (n + j1 + j2 + 1) * sizeof( LDAPControl * ) + ( j1 + j2 ) * sizeof( LDAPControl ),
+			op->o_tmpmemctx );
+	if ( j1 ) {
+		ctrls[ 0 ] = (LDAPControl *)&ctrls[ n + j1 + j2 + 1 ];
+		*ctrls[ 0 ] = c[ 0 ];
+		for ( i = 1; i < j1; i++ ) {
+			ctrls[ i ] = &ctrls[ 0 ][ i ];
+			*ctrls[ i ] = c[ i ];
+		}
+	}
+
+	i = 0;
+	if ( op->o_ctrls ) {
+		LDAPControl *proxyauthz = ldap_control_find(
+				LDAP_CONTROL_PROXY_AUTHZ, op->o_ctrls, NULL );
+
+		for ( i = 0; op->o_ctrls[ i ]; i++ ) {
+			/* Only replace it if we generated one */
+			if ( j1 && proxyauthz && proxyauthz == op->o_ctrls[ i ] ) {
+				/* Frontend has already checked only one is present */
+				assert( skipped == 0 );
+				skipped++;
+				continue;
+			}
+			ctrls[ i + j1 - skipped ] = op->o_ctrls[ i ];
+		}
+	}
+
+	n += j1 - skipped;
+	if ( j2 ) {
+		ctrls[ n ] = (LDAPControl *)&ctrls[ n + j2 + 1 ] + j1;
+		*ctrls[ n ] = c[ j1 ];
+		for ( i = 1; i < j2; i++ ) {
+			ctrls[ n + i ] = &ctrls[ n ][ i ];
+			*ctrls[ n + i ] = c[ i ];
+		}
+	}
+
+	ctrls[ n + j2 ] = NULL;
+
+done:;
+	if ( ctrls == NULL ) {
+		ctrls = op->o_ctrls;
+	}
+
+	*pctrls = ctrls;
+
+	return rs->sr_err;
+}
+
+
+/*
+ * asyncmeta_dobind_init()
+ *
+ * initiates bind for a candidate target
+ */
+meta_search_candidate_t
+asyncmeta_dobind_init(Operation *op, SlapReply *rs, bm_context_t *bc, a_metaconn_t *mc, int candidate)
+{
+	SlapReply		*candidates = bc->candidates;
+	a_metainfo_t		*mi = ( a_metainfo_t * )mc->mc_info;
+	a_metatarget_t		*mt = mi->mi_targets[ candidate ];
+	a_metasingleconn_t	*msc = &mc->mc_conns[ candidate ];
+	struct berval		binddn = msc->msc_bound_ndn,
+				cred = msc->msc_cred;
+	int			method;
+
+	int			rc;
+	ber_int_t	msgid;
+
+	meta_search_candidate_t	retcode;
+
+	Debug( LDAP_DEBUG_TRACE, "%s >>> asyncmeta_dobind_init[%d] msc %p\n",
+		op->o_log_prefix, candidate, msc );
+
+	if ( mc->mc_authz_target == META_BOUND_ALL ) {
+		return META_SEARCH_CANDIDATE;
+	}
+
+	if ( slapd_shutdown ) {
+		rs->sr_err = LDAP_UNAVAILABLE;
+		return META_SEARCH_ERR;
+	}
+
+	retcode = META_SEARCH_BINDING;
+	if ( LDAP_BACK_CONN_ISBOUND( msc ) || LDAP_BACK_CONN_ISANON( msc ) ) {
+		/* already bound (or anonymous) */
+
+#ifdef DEBUG_205
+		char	buf[ SLAP_TEXT_BUFLEN ] = { '\0' };
+		int	bound = 0;
+
+		if ( LDAP_BACK_CONN_ISBOUND( msc ) ) {
+			bound = 1;
+		}
+
+		Debug( LDAP_DEBUG_ANY,
+		       "### %s asyncmeta_dobind_init[%d] mc=%p ld=%p%s DN=\"%s\"\n",
+		       op->o_log_prefix, candidate, (void *)mc,
+		       (void *)msc->msc_ld, bound ? " bound" : " anonymous",
+		       bound == 0 ? "" : msc->msc_bound_ndn.bv_val );
+#endif /* DEBUG_205 */
+
+		retcode = META_SEARCH_CANDIDATE;
+
+	} else if ( META_BACK_CONN_CREATING( msc ) || LDAP_BACK_CONN_BINDING( msc ) ) {
+		/* another thread is binding the target for this conn; wait */
+
+#ifdef DEBUG_205
+
+		Debug( LDAP_DEBUG_ANY,
+		       "### %s asyncmeta_dobind_init[%d] mc=%p ld=%p needbind\n",
+		       op->o_log_prefix, candidate, (void *)mc,
+		       (void *)msc->msc_ld );
+#endif /* DEBUG_205 */
+
+		candidates[ candidate ].sr_msgid = META_MSGID_NEED_BIND;
+		retcode = META_SEARCH_NEED_BIND;
+	} else {
+		/* we'll need to bind the target for this conn */
+
+#ifdef DEBUG_205
+
+		Debug( LDAP_DEBUG_ANY,
+		       "### %s asyncmeta_dobind_init[%d] mc=%p ld=%p binding\n",
+		       op->o_log_prefix, candidate, (void *)mc,
+		       (void *)msc->msc_ld );
+#endif /* DEBUG_205 */
+
+		if ( msc->msc_ld == NULL ) {
+			/* for some reason (e.g. because formerly in "binding"
+			 * state, with eventual connection expiration or invalidation)
+			 * it was not initialized as expected */
+
+			Debug( LDAP_DEBUG_ANY, "%s asyncmeta_dobind_init[%d] mc=%p ld=NULL\n",
+				op->o_log_prefix, candidate, (void *)mc );
+
+			rc = asyncmeta_init_one_conn( op, rs, mc, candidate,
+						      LDAP_BACK_CONN_ISPRIV( mc ), LDAP_BACK_DONTSEND, 0 );
+
+			switch ( rc ) {
+			case LDAP_SUCCESS:
+				assert( msc->msc_ld != NULL );
+				break;
+
+			case LDAP_SERVER_DOWN:
+			case LDAP_UNAVAILABLE:
+				goto down;
+
+			default:
+				goto other;
+			}
+		}
+
+		LDAP_BACK_CONN_BINDING_SET( msc );
+	}
+
+	if ( retcode != META_SEARCH_BINDING ) {
+		return retcode;
+	}
+
+	if ( op->o_conn != NULL &&
+		!op->o_do_not_cache &&
+		( BER_BVISNULL( &msc->msc_bound_ndn ) ||
+			BER_BVISEMPTY( &msc->msc_bound_ndn ) ||
+			( mt->mt_idassert_flags & LDAP_BACK_AUTH_OVERRIDE ) ) )
+	{
+		rc = asyncmeta_back_proxy_authz_cred( mc, candidate, op, rs, LDAP_BACK_DONTSEND, &binddn, &cred, &method );
+		switch ( rc ) {
+		case LDAP_SUCCESS:
+			break;
+		case LDAP_UNAVAILABLE:
+			goto down;
+		default:
+			goto other;
+		}
+
+		/* NOTE: we copy things here, even if bind didn't succeed yet,
+		 * because the connection is not shared until bind is over */
+		if ( !BER_BVISNULL( &binddn ) ) {
+			ber_bvreplace( &msc->msc_bound_ndn, &binddn );
+			if ( META_BACK_TGT_SAVECRED( mt ) && !BER_BVISNULL( &cred ) ) {
+				if ( !BER_BVISNULL( &msc->msc_cred ) ) {
+					memset( msc->msc_cred.bv_val, 0,
+						msc->msc_cred.bv_len );
+				}
+				ber_bvreplace( &msc->msc_cred, &cred );
+			}
+		}
+		if ( LDAP_BACK_CONN_ISBOUND( msc ) ) {
+			/* apparently, idassert was configured with SASL bind,
+			 * so bind occurred inside meta_back_proxy_authz_cred() */
+			LDAP_BACK_CONN_BINDING_CLEAR( msc );
+			return META_SEARCH_CANDIDATE;
+		}
+
+		/* paranoid */
+		switch ( method ) {
+		case LDAP_AUTH_NONE:
+		case LDAP_AUTH_SIMPLE:
+			/* do a simple bind with binddn, cred */
+			break;
+
+		default:
+			assert( 0 );
+			break;
+		}
+	}
+
+	assert( msc->msc_ld != NULL );
+
+	if ( !BER_BVISEMPTY( &binddn ) && BER_BVISEMPTY( &cred ) ) {
+		/* bind anonymously? */
+		Debug( LDAP_DEBUG_ANY, "%s asyncmeta_dobind_init[%d] mc=%p: "
+			"non-empty dn with empty cred; binding anonymously\n",
+			op->o_log_prefix, candidate, (void *)mc );
+		cred = slap_empty_bv;
+
+	} else if ( BER_BVISEMPTY( &binddn ) && !BER_BVISEMPTY( &cred ) ) {
+		/* error */
+		Debug( LDAP_DEBUG_ANY, "%s asyncmeta_dobind_init[%d] mc=%p: "
+			"empty dn with non-empty cred: error\n",
+			op->o_log_prefix, candidate, (void *)mc );
+		rc = LDAP_OTHER;
+		goto other;
+	}
+retry_bind:
+	if ( LogTest( asyncmeta_debug ) ) {
+		char	time_buf[ SLAP_TEXT_BUFLEN ];
+		asyncmeta_get_timestamp(time_buf);
+		Debug( asyncmeta_debug, "[%s] asyncmeta_dobind_init sending bind msc: %p\n",
+		      time_buf, msc );
+	}
+	rc = ldap_sasl_bind( msc->msc_ld, binddn.bv_val, LDAP_SASL_SIMPLE, &cred,
+			NULL, NULL, &msgid );
+	ldap_get_option( msc->msc_ld, LDAP_OPT_RESULT_CODE, &rc );
+	if ( LogTest( asyncmeta_debug ) ) {
+		char	time_buf[ SLAP_TEXT_BUFLEN ];
+		asyncmeta_get_timestamp(time_buf);
+		Debug( asyncmeta_debug, "[%s] asyncmeta_dobind_init rc=%d msc: %p\n",
+		      time_buf, rc, msc );
+	}
+	if ( LogTest( LDAP_DEBUG_TRACE )) {
+		ber_socket_t s;
+		char sockname[LDAP_IPADDRLEN];
+		struct berval sockbv = BER_BVC( sockname );
+		Sockaddr addr;
+		socklen_t len = sizeof( addr );
+
+		ldap_get_option( msc->msc_ld, LDAP_OPT_DESC, &s );
+		getsockname( s, &addr.sa_addr, &len );
+		ldap_pvt_sockaddrstr( &addr, &sockbv );
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_dobind_init msc %p ld %p ldr %p fd %d addr %s\n",
+			op->o_log_prefix, msc, msc->msc_ld, msc->msc_ldr, s, sockname );
+	}
+
+	if (rc == LDAP_SERVER_DOWN ) {
+		goto down;
+	} else if (rc == LDAP_BUSY) {
+		if (rs->sr_text == NULL) {
+			rs->sr_text = "Unable to establish LDAP connection to target within the specified network timeout.";
+		}
+		LDAP_BACK_CONN_BINDING_CLEAR( msc );
+		goto other;
+	}
+	/* mark as need bind so it gets send when the bind response is received */
+	candidates[ candidate ].sr_msgid = META_MSGID_NEED_BIND;
+	asyncmeta_set_msc_time(msc);
+#ifdef DEBUG_205
+	Debug( LDAP_DEBUG_ANY,
+	       "### %s asyncmeta_dobind_init[%d] mc=%p ld=%p rc=%d\n",
+	       op->o_log_prefix, candidate, (void *)mc,
+	       (void *)mc->mc_conns[candidate].msc_ld, rc );
+#endif /* DEBUG_205 */
+
+	switch ( rc ) {
+	case LDAP_SUCCESS:
+		assert( msgid >= 0 );
+		if ( LogTest( asyncmeta_debug ) ) {
+			char	time_buf[ SLAP_TEXT_BUFLEN ];
+			asyncmeta_get_timestamp(time_buf);
+			Debug( asyncmeta_debug, "[%s] asyncmeta_dobind_init sending bind success msc: %p\n",
+			      time_buf, msc );
+		}
+		META_BINDING_SET( &candidates[ candidate ] );
+		rs->sr_err = LDAP_SUCCESS;
+		msc->msc_binding_time = slap_get_time();
+		return META_SEARCH_BINDING;
+
+	case LDAP_X_CONNECTING:
+		/* must retry, same conn */
+		candidates[ candidate ].sr_msgid = META_MSGID_CONNECTING;
+		LDAP_BACK_CONN_BINDING_CLEAR( msc );
+		goto retry_bind;
+
+	case LDAP_SERVER_DOWN:
+down:;
+		retcode = META_SEARCH_ERR;
+		rs->sr_err = LDAP_UNAVAILABLE;
+		if (rs->sr_text == NULL) {
+			rs->sr_text = "Unable to bind to remote target - target down or unavailable";
+		}
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+                LDAP_BACK_CONN_BINDING_CLEAR( msc );
+		break;
+
+		/* fall thru */
+
+	default:
+other:;
+		rs->sr_err = rc;
+		rc = slap_map_api2result( rs );
+		candidates[ candidate ].sr_err = rc;
+		if ( META_BACK_ONERR_STOP( mi ) ) {
+			retcode = META_SEARCH_ERR;
+
+		} else {
+			retcode = META_SEARCH_NOT_CANDIDATE;
+		}
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+                LDAP_BACK_CONN_BINDING_CLEAR( msc );
+		break;
+	}
+
+	return retcode;
+}
+
+
+
+
+meta_search_candidate_t
+asyncmeta_dobind_init_with_retry(Operation *op, SlapReply *rs, bm_context_t *bc, a_metaconn_t *mc, int candidate)
+{
+
+	int rc;
+	a_metasingleconn_t *msc = &mc->mc_conns[candidate];
+	a_metainfo_t		*mi = mc->mc_info;
+	a_metatarget_t		*mt = mi->mi_targets[ candidate ];
+
+	if (META_BACK_CONN_INVALID(msc) || (LDAP_BACK_CONN_BINDING( msc ) && msc->msc_binding_time > 0
+					    && (msc->msc_binding_time + mt->mt_timeout[ SLAP_OP_BIND ]) < slap_get_time())) {
+		char	buf[ SLAP_TEXT_BUFLEN ];
+		snprintf( buf, sizeof( buf ), "called from %s:%d", __FILE__, __LINE__ );
+		ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex );
+		asyncmeta_reset_msc(NULL, mc, candidate, 0, buf);
+
+		rc = asyncmeta_init_one_conn( op, rs, mc, candidate,
+					      LDAP_BACK_CONN_ISPRIV( mc ), LDAP_BACK_DONTSEND, 0 );
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+	}
+
+	if ( LDAP_BACK_CONN_ISBOUND( msc ) || LDAP_BACK_CONN_ISANON( msc ) ) {
+		if ( mc->pending_ops > 1 ) {
+			asyncmeta_send_all_pending_ops( mc, candidate, op->o_threadctx, 1 );
+		}
+		return META_SEARCH_CANDIDATE;
+	}
+
+retry_dobind:
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex );
+	rc = asyncmeta_dobind_init(op, rs, bc, mc, candidate);
+	if (rs->sr_err != LDAP_UNAVAILABLE && rs->sr_err != LDAP_BUSY) {
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+		return rc;
+	} else if (bc->nretries[candidate] == 0) {
+		char	buf[ SLAP_TEXT_BUFLEN ];
+		snprintf( buf, sizeof( buf ), "called from %s:%d", __FILE__, __LINE__ );
+		asyncmeta_reset_msc(NULL, mc, candidate, 0, buf);
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+		return rc;
+	}
+	/* need to retry */
+	bc->nretries[candidate]--;
+	if ( LogTest( LDAP_DEBUG_TRACE ) ) {
+		/* this lock is required; however,
+		 * it's invoked only when logging is on */
+		ldap_pvt_thread_mutex_lock( &mt->mt_uri_mutex );
+		Debug( LDAP_DEBUG_ANY,
+		       "%s asyncmeta_dobind_init_with_retry[%d]: retrying URI=\"%s\" DN=\"%s\".\n",
+		       op->o_log_prefix, candidate, mt->mt_uri,
+		       BER_BVISNULL(&msc->msc_bound_ndn) ? "" : msc->msc_bound_ndn.bv_val );
+		ldap_pvt_thread_mutex_unlock( &mt->mt_uri_mutex );
+	}
+
+	asyncmeta_reset_msc(NULL, mc, candidate, 0,  __FUNCTION__);
+	rc = asyncmeta_init_one_conn( op, rs, mc, candidate,
+				      LDAP_BACK_CONN_ISPRIV( mc ), LDAP_BACK_DONTSEND, 0 );
+
+	if (rs->sr_err != LDAP_SUCCESS) {
+		asyncmeta_reset_msc(NULL, mc, candidate, 0,  __FUNCTION__);
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+		return META_SEARCH_ERR;
+	}
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+	goto retry_dobind;
+	return rc;
+}
diff --git a/servers/slapd/back-asyncmeta/candidates.c b/servers/slapd/back-asyncmeta/candidates.c
new file mode 100644
index 0000000..5f3b228
--- /dev/null
+++ b/servers/slapd/back-asyncmeta/candidates.c
@@ -0,0 +1,239 @@
+/* candidates.c - candidate targets selection and processing for
+ * back-asyncmeta */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016-2022 The OpenLDAP Foundation.
+ * Portions Copyright 2016 Symas Corporation.
+ * 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 developed by Symas Corporation
++ * based on back-meta module for inclusion in OpenLDAP Software.
++ * This work was sponsored by Ericsson. */
+
+#include "portable.h"
+
+#include <stdio.h>
+#include "ac/string.h"
+
+#include "slap.h"
+#include "../back-ldap/back-ldap.h"
+#include "back-asyncmeta.h"
+
+/*
+ * The meta-directory has one suffix, called <suffix>.
+ * It handles a pool of target servers, each with a branch suffix
+ * of the form <branch X>,<suffix>, where <branch X> may be empty.
+ *
+ * When the meta-directory receives a request with a request DN that belongs
+ * to a branch, the corresponding target is invoked. When the request DN
+ * does not belong to a specific branch, all the targets that
+ * are compatible with the request DN are selected as candidates, and
+ * the request is spawned to all the candidate targets
+ *
+ * A request is characterized by a request DN. The following cases are
+ * handled:
+ * 	- the request DN is the suffix: <dn> == <suffix>,
+ * 		all the targets are candidates (search ...)
+ * 	- the request DN is a branch suffix: <dn> == <branch X>,<suffix>, or
+ * 	- the request DN is a subtree of a branch suffix:
+ * 		<dn> == <rdn>,<branch X>,<suffix>,
+ * 		the target is the only candidate.
+ *
+ * A possible extension will include the handling of multiple suffixes
+ */
+
+static a_metasubtree_t *
+asyncmeta_subtree_match( a_metatarget_t *mt, struct berval *ndn, int scope )
+{
+	a_metasubtree_t *ms = mt->mt_subtree;
+
+	for ( ms = mt->mt_subtree; ms; ms = ms->ms_next ) {
+		switch ( ms->ms_type ) {
+		case META_ST_SUBTREE:
+			if ( dnIsSuffix( ndn, &ms->ms_dn ) ) {
+				return ms;
+			}
+			break;
+
+		case META_ST_SUBORDINATE:
+			if ( dnIsSuffix( ndn, &ms->ms_dn ) &&
+				( ndn->bv_len > ms->ms_dn.bv_len || scope != LDAP_SCOPE_BASE ) )
+			{
+				return ms;
+			}
+			break;
+
+		case META_ST_REGEX:
+			/* NOTE: cannot handle scope */
+			if ( regexec( &ms->ms_regex, ndn->bv_val, 0, NULL, 0 ) == 0 ) {
+				return ms;
+			}
+			break;
+		}
+	}
+
+	return NULL;
+}
+
+/*
+ * returns 1 if suffix is candidate for dn, otherwise 0
+ *
+ * Note: this function should never be called if dn is the <suffix>.
+ */
+int
+asyncmeta_is_candidate(
+	a_metatarget_t	*mt,
+	struct berval	*ndn,
+	int		scope )
+{
+	struct berval rdn;
+	int d = ndn->bv_len - mt->mt_nsuffix.bv_len;
+
+	if ( d >= 0 ) {
+		if ( !dnIsSuffix( ndn, &mt->mt_nsuffix ) ) {
+			return META_NOT_CANDIDATE;
+		}
+
+		/*
+		 * |  match  | exclude |
+		 * +---------+---------+-------------------+
+		 * |    T    |    T    | not candidate     |
+		 * |    F    |    T    | continue checking |
+		 * +---------+---------+-------------------+
+		 * |    T    |    F    | candidate         |
+		 * |    F    |    F    | not candidate     |
+		 * +---------+---------+-------------------+
+		 */
+
+		if ( mt->mt_subtree ) {
+			int match = ( asyncmeta_subtree_match( mt, ndn, scope ) != NULL );
+
+			if ( !mt->mt_subtree_exclude ) {
+				return match ? META_CANDIDATE : META_NOT_CANDIDATE;
+			}
+
+			if ( match /* && mt->mt_subtree_exclude */ ) {
+				return META_NOT_CANDIDATE;
+			}
+		}
+
+		switch ( mt->mt_scope ) {
+		case LDAP_SCOPE_SUBTREE:
+		default:
+			return META_CANDIDATE;
+
+		case LDAP_SCOPE_SUBORDINATE:
+			if ( d > 0 ) {
+				return META_CANDIDATE;
+			}
+			break;
+
+		/* nearly useless; not allowed by config */
+		case LDAP_SCOPE_ONELEVEL:
+			if ( d > 0 ) {
+				rdn.bv_val = ndn->bv_val;
+				rdn.bv_len = (ber_len_t)d - STRLENOF( "," );
+				if ( dnIsOneLevelRDN( &rdn ) ) {
+					return META_CANDIDATE;
+				}
+			}
+			break;
+
+		/* nearly useless; not allowed by config */
+		case LDAP_SCOPE_BASE:
+			if ( d == 0 ) {
+				return META_CANDIDATE;
+			}
+			break;
+		}
+
+	} else /* if ( d < 0 ) */ {
+		if ( !dnIsSuffix( &mt->mt_nsuffix, ndn ) ) {
+			return META_NOT_CANDIDATE;
+		}
+
+		switch ( scope ) {
+		case LDAP_SCOPE_SUBTREE:
+		case LDAP_SCOPE_SUBORDINATE:
+			/*
+			 * suffix longer than dn, but common part matches
+			 */
+			return META_CANDIDATE;
+
+		case LDAP_SCOPE_ONELEVEL:
+			rdn.bv_val = mt->mt_nsuffix.bv_val;
+			rdn.bv_len = (ber_len_t)(-d) - STRLENOF( "," );
+			if ( dnIsOneLevelRDN( &rdn ) ) {
+				return META_CANDIDATE;
+			}
+			break;
+		}
+	}
+
+	return META_NOT_CANDIDATE;
+}
+
+/*
+ * meta_back_select_unique_candidate
+ *
+ * returns the index of the candidate in case it is unique, otherwise
+ * META_TARGET_NONE if none matches, or
+ * META_TARGET_MULTIPLE if more than one matches
+ * Note: ndn MUST be normalized.
+ */
+int
+asyncmeta_select_unique_candidate(
+	a_metainfo_t	*mi,
+	struct berval	*ndn )
+{
+	int	i, candidate = META_TARGET_NONE;
+
+	for ( i = 0; i < mi->mi_ntargets; i++ ) {
+		a_metatarget_t	*mt = mi->mi_targets[ i ];
+
+		if ( asyncmeta_is_candidate( mt, ndn, LDAP_SCOPE_BASE ) ) {
+			if ( candidate == META_TARGET_NONE ) {
+				candidate = i;
+
+			}
+		}
+	}
+
+	return candidate;
+}
+
+/*
+ * asyncmeta_clear_unused_candidates
+ *
+ * clears all candidates except candidate
+ */
+int
+asyncmeta_clear_unused_candidates(
+	Operation	*op,
+	int		candidate,
+	a_metaconn_t	*mc,
+	SlapReply	*candidates)
+{
+	a_metainfo_t	*mi = mc->mc_info;
+	int		i;
+
+	for ( i = 0; i < mi->mi_ntargets; ++i ) {
+		if ( i == candidate ) {
+			continue;
+		}
+		META_CANDIDATE_RESET( &candidates[ i ] );
+	}
+
+	return 0;
+}
diff --git a/servers/slapd/back-asyncmeta/compare.c b/servers/slapd/back-asyncmeta/compare.c
new file mode 100644
index 0000000..1349cac
--- /dev/null
+++ b/servers/slapd/back-asyncmeta/compare.c
@@ -0,0 +1,304 @@
+/* compare.c - compare exop handler for back-asyncmeta */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016-2022 The OpenLDAP Foundation.
+ * Portions Copyright 2016 Symas Corporation.
+ * 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 developed by Symas Corporation
++ * based on back-meta module for inclusion in OpenLDAP Software.
++ * This work was sponsored by Ericsson. */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/string.h>
+#include <ac/socket.h>
+#include "slap.h"
+#include "../../../libraries/liblber/lber-int.h"
+#include "../../../libraries/libldap/ldap-int.h"
+#include "../back-ldap/back-ldap.h"
+#include "back-asyncmeta.h"
+
+meta_search_candidate_t
+asyncmeta_back_compare_start(Operation *op,
+			     SlapReply *rs,
+			     a_metaconn_t *mc,
+			     bm_context_t *bc,
+			     int candidate,
+			     int do_lock)
+{
+	a_dncookie	dc;
+	a_metainfo_t	*mi = mc->mc_info;
+	a_metatarget_t	*mt = mi->mi_targets[ candidate ];
+	struct berval	c_attr = op->orc_ava->aa_desc->ad_cname;
+	struct berval	mdn = BER_BVNULL;
+	struct berval	mapped_value = op->orc_ava->aa_value;
+	int rc = 0;
+	LDAPControl	**ctrls = NULL;
+	meta_search_candidate_t retcode = META_SEARCH_CANDIDATE;
+	BerElement *ber = NULL;
+	a_metasingleconn_t	*msc = &mc->mc_conns[ candidate ];
+	SlapReply		*candidates = bc->candidates;
+	ber_int_t	msgid;
+
+	dc.op = op;
+	dc.target = mt;
+	dc.memctx = op->o_tmpmemctx;
+	dc.to_from = MASSAGE_REQ;
+
+	asyncmeta_dn_massage( &dc, &op->o_req_dn, &mdn );
+
+	if ( op->orc_ava->aa_desc->ad_type->sat_syntax == slap_schema.si_syn_distinguishedName )
+		asyncmeta_dn_massage( &dc, &op->orc_ava->aa_value, &mapped_value );
+
+	asyncmeta_set_msc_time(msc);
+	ctrls = op->o_ctrls;
+	if ( asyncmeta_controls_add( op, rs, mc, candidate, bc->is_root,&ctrls ) != LDAP_SUCCESS )
+	{
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		retcode = META_SEARCH_ERR;
+		goto done;
+	}
+	/* someone might have reset the connection */
+	if (!( LDAP_BACK_CONN_ISBOUND( msc )
+	       || LDAP_BACK_CONN_ISANON( msc )) || msc->msc_ld == NULL ) {
+		Debug( asyncmeta_debug, "msc %p not initialized at %s:%d\n", msc, __FILE__, __LINE__ );
+		goto error_unavailable;
+	}
+
+	ber = ldap_build_compare_req( msc->msc_ld, mdn.bv_val, c_attr.bv_val, &mapped_value,
+			ctrls, NULL, &msgid);
+
+	if (!ber) {
+		Debug( asyncmeta_debug, "%s asyncmeta_back_compare_start: Operation encoding failed with errno %d\n",
+		       op->o_log_prefix, msc->msc_ld->ld_errno );
+		rs->sr_err = LDAP_OPERATIONS_ERROR;
+		rs->sr_text = "Failed to encode proxied request";
+		retcode = META_SEARCH_ERR;
+		goto done;
+	}
+
+	if (ber) {
+		struct timeval tv = {0, mt->mt_network_timeout*1000};
+		ber_socket_t s;
+		if (!( LDAP_BACK_CONN_ISBOUND( msc )
+		       || LDAP_BACK_CONN_ISANON( msc )) || msc->msc_ld == NULL ) {
+			Debug( asyncmeta_debug, "msc %p not initialized at %s:%d\n", msc, __FILE__, __LINE__ );
+			goto error_unavailable;
+		}
+
+		ldap_get_option( msc->msc_ld, LDAP_OPT_DESC, &s );
+		if (s < 0) {
+			Debug( asyncmeta_debug, "msc %p not initialized at %s:%d\n", msc, __FILE__, __LINE__ );
+			goto error_unavailable;
+		}
+		rc = ldap_int_poll( msc->msc_ld, s, &tv, 1);
+		if (rc < 0) {
+			Debug( asyncmeta_debug, "msc %p not writable within network timeout %s:%d\n", msc, __FILE__, __LINE__ );
+			if ((msc->msc_result_time + META_BACK_RESULT_INTERVAL) < slap_get_time()) {
+				rc = LDAP_SERVER_DOWN;
+			} else {
+				goto error_unavailable;
+			}
+		} else {
+			candidates[ candidate ].sr_msgid = msgid;
+			rc = ldap_send_initial_request( msc->msc_ld, LDAP_REQ_COMPARE,
+							mdn.bv_val, ber, msgid );
+			if (rc == msgid)
+				rc = LDAP_SUCCESS;
+			else
+				rc = LDAP_SERVER_DOWN;
+			ber = NULL;
+		}
+
+		switch ( rc ) {
+		case LDAP_SUCCESS:
+			retcode = META_SEARCH_CANDIDATE;
+			asyncmeta_set_msc_time(msc);
+			goto done;
+
+		case LDAP_SERVER_DOWN:
+			/* do not lock if called from asyncmeta_handle_bind_result. Also do not reset the connection */
+			if (do_lock > 0) {
+				ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+				asyncmeta_reset_msc(NULL, mc, candidate, 0, __FUNCTION__);
+				ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			}
+			/* fall though*/
+		default:
+			Debug( asyncmeta_debug, "msc %p ldap_send_initial_request failed. %s:%d\n", msc, __FILE__, __LINE__ );
+			goto error_unavailable;
+		}
+	}
+
+error_unavailable:
+	if (ber)
+		ber_free(ber, 1);
+	switch (bc->nretries[candidate]) {
+	case -1: /* nretries = forever */
+		retcode = META_SEARCH_NEED_BIND;
+		break;
+	case 0: /* no retries left */
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		rs->sr_err = LDAP_UNAVAILABLE;
+		rs->sr_text = "Unable to send compare request to target";
+		retcode = META_SEARCH_ERR;
+		break;
+	default: /* more retries left - try to rebind and go again */
+		retcode = META_SEARCH_NEED_BIND;
+		bc->nretries[candidate]--;
+		break;
+	}
+done:
+	(void)mi->mi_ldap_extra->controls_free( op, rs, &ctrls );
+
+	if ( op->orc_ava->aa_value.bv_val != mapped_value.bv_val ) {
+		op->o_tmpfree( mapped_value.bv_val, op->o_tmpmemctx );
+	}
+
+	if ( mdn.bv_val != op->o_req_dn.bv_val ) {
+		op->o_tmpfree( mdn.bv_val, op->o_tmpmemctx );
+	}
+
+	Debug( LDAP_DEBUG_TRACE, "%s <<< asyncmeta_back_compare_start[%p]=%d\n", op->o_log_prefix, msc, candidates[candidate].sr_msgid );
+	return retcode;
+}
+
+int
+asyncmeta_back_compare( Operation *op, SlapReply *rs )
+{
+	a_metainfo_t	*mi = ( a_metainfo_t * )op->o_bd->be_private;
+	a_metatarget_t	*mt;
+	a_metaconn_t	*mc;
+	int		rc, candidate = -1;
+	void *thrctx = op->o_threadctx;
+	bm_context_t *bc;
+	SlapReply *candidates;
+	time_t current_time = slap_get_time();
+	int max_pending_ops = (mi->mi_max_pending_ops == 0) ? META_BACK_CFG_MAX_PENDING_OPS : mi->mi_max_pending_ops;
+
+	Debug(LDAP_DEBUG_ARGS, "==> asyncmeta_back_compare: %s\n",
+	      op->o_req_dn.bv_val );
+
+	if (current_time > op->o_time) {
+		Debug( asyncmeta_debug, "==> asyncmeta_back_compare[%s]: o_time:[%ld], current time: [%ld]\n",
+		       op->o_log_prefix, op->o_time, current_time );
+	}
+	asyncmeta_new_bm_context(op, rs, &bc, mi->mi_ntargets, mi );
+	if (bc == NULL) {
+		rs->sr_err = LDAP_OTHER;
+		send_ldap_result(op, rs);
+		return rs->sr_err;
+	}
+
+	candidates = bc->candidates;
+	mc = asyncmeta_getconn( op, rs, candidates, &candidate, LDAP_BACK_DONTSEND, 0);
+	if ( !mc || rs->sr_err != LDAP_SUCCESS) {
+		send_ldap_result(op, rs);
+		return rs->sr_err;
+	}
+
+	mt = mi->mi_targets[ candidate ];
+	bc->timeout = mt->mt_timeout[ SLAP_OP_COMPARE ];
+	bc->retrying = LDAP_BACK_RETRYING;
+	bc->sendok = ( LDAP_BACK_SENDRESULT | bc->retrying );
+	bc->stoptime = op->o_time + bc->timeout;
+	bc->bc_active = 1;
+
+	if (mc->pending_ops >= max_pending_ops) {
+		rs->sr_err = LDAP_BUSY;
+		rs->sr_text = "Maximum pending ops limit exceeded";
+		send_ldap_result(op, rs);
+		return rs->sr_err;
+	}
+
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	rc = asyncmeta_add_message_queue(mc, bc);
+	mc->mc_conns[candidate].msc_active++;
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+
+	if (rc != LDAP_SUCCESS) {
+		rs->sr_err = LDAP_BUSY;
+		rs->sr_text = "Maximum pending ops limit exceeded";
+		send_ldap_result(op, rs);
+		ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+		mc->mc_conns[candidate].msc_active--;
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+		goto finish;
+	}
+
+retry:
+	if (bc->timeout && bc->stoptime < slap_get_time()) {
+		int		timeout_err;
+		timeout_err = op->o_protocol >= LDAP_VERSION3 ?
+			LDAP_ADMINLIMIT_EXCEEDED : LDAP_OTHER;
+		rs->sr_err = timeout_err;
+		rs->sr_text = "Operation timed out before it was sent to target";
+		asyncmeta_error_cleanup(op, rs, bc, mc, candidate);
+		goto finish;
+	}
+
+	rc = asyncmeta_dobind_init_with_retry(op, rs, bc, mc, candidate);
+	switch (rc)
+	{
+	case META_SEARCH_CANDIDATE:
+		/* target is already bound, just send the request */
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_compare:  "
+		       "cnd=\"%d\"\n", op->o_log_prefix, candidate );
+
+		rc = asyncmeta_back_compare_start( op, rs, mc, bc, candidate, 1);
+		if (rc == META_SEARCH_ERR) {
+			asyncmeta_error_cleanup(op, rs, bc, mc, candidate);
+			goto finish;
+
+		} else if (rc == META_SEARCH_NEED_BIND) {
+			goto retry;
+		}
+		break;
+	case META_SEARCH_NOT_CANDIDATE:
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_compare: NOT_CANDIDATE "
+		       "cnd=\"%d\"\n", op->o_log_prefix, candidate );
+		asyncmeta_error_cleanup(op, rs, bc, mc, candidate);
+		goto finish;
+
+	case META_SEARCH_NEED_BIND:
+	case META_SEARCH_BINDING:
+			Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_compare: BINDING "
+			       "cnd=\"%d\" %p\n", op->o_log_prefix, candidate , &mc->mc_conns[candidate]);
+			/* Todo add the context to the message queue but do not send the request
+			   the receiver must send this when we are done binding */
+			/* question - how would do receiver know to which targets??? */
+			break;
+
+	case META_SEARCH_ERR:
+			Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_compare: ERR "
+			       "cnd=\"%d\"\n", op->o_log_prefix, candidate );
+			asyncmeta_error_cleanup(op, rs, bc, mc, candidate);
+			goto finish;
+		default:
+			assert( 0 );
+			break;
+		}
+
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	mc->mc_conns[candidate].msc_active--;
+	asyncmeta_start_one_listener(mc, candidates, bc, candidate);
+	bc->bc_active--;
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+	rs->sr_err = SLAPD_ASYNCOP;
+finish:
+	return rs->sr_err;
+}
diff --git a/servers/slapd/back-asyncmeta/config.c b/servers/slapd/back-asyncmeta/config.c
new file mode 100644
index 0000000..849ac01
--- /dev/null
+++ b/servers/slapd/back-asyncmeta/config.c
@@ -0,0 +1,2443 @@
+/* config.c - configuration parsing for back-asyncmeta */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016-2022 The OpenLDAP Foundation.
+ * Portions Copyright 2016 Symas Corporation.
+ * 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 developed by Symas Corporation
+ * based on back-meta module for inclusion in OpenLDAP Software.
+ * This work was sponsored by Ericsson. */
+
+#include "portable.h"
+
+#include <stdio.h>
+#include <ctype.h>
+
+#include <ac/string.h>
+#include <ac/socket.h>
+
+#include "slap.h"
+#include "slap-config.h"
+#include "lutil.h"
+#include "ldif.h"
+#include "../back-ldap/back-ldap.h"
+#include "back-asyncmeta.h"
+
+#ifdef LDAP_DEVEL
+#define SLAP_AUTH_DN	1
+#endif
+
+static ConfigDriver asyncmeta_back_cf_gen;
+static ConfigLDAPadd asyncmeta_ldadd;
+static ConfigCfAdd asyncmeta_cfadd;
+
+/* Three sets of enums:
+ *	1) attrs that are only valid in the base config
+ *	2) attrs that are valid in base or target
+ *	3) attrs that are only valid in a target
+ */
+
+/* Base attrs */
+enum {
+	LDAP_BACK_CFG_DNCACHE_TTL = 1,
+	LDAP_BACK_CFG_IDLE_TIMEOUT,
+	LDAP_BACK_CFG_ONERR,
+	LDAP_BACK_CFG_PSEUDOROOT_BIND_DEFER,
+	LDAP_BACK_CFG_CONNPOOLMAX,
+	LDAP_BACK_CFG_MAX_TIMEOUT_OPS,
+	LDAP_BACK_CFG_MAX_PENDING_OPS,
+	LDAP_BACK_CFG_MAX_TARGET_CONNS,
+	LDAP_BACK_CFG_LAST_BASE,
+};
+
+/* Base or target */
+enum {
+	LDAP_BACK_CFG_BIND_TIMEOUT = LDAP_BACK_CFG_LAST_BASE,
+	LDAP_BACK_CFG_CANCEL,
+	LDAP_BACK_CFG_CHASE,
+	LDAP_BACK_CFG_CLIENT_PR,
+	LDAP_BACK_CFG_DEFAULT_T,
+	LDAP_BACK_CFG_NETWORK_TIMEOUT,
+	LDAP_BACK_CFG_NOREFS,
+	LDAP_BACK_CFG_NOUNDEFFILTER,
+	LDAP_BACK_CFG_NRETRIES,
+	LDAP_BACK_CFG_QUARANTINE,
+	LDAP_BACK_CFG_REBIND,
+	LDAP_BACK_CFG_TIMEOUT,
+	LDAP_BACK_CFG_VERSION,
+	LDAP_BACK_CFG_ST_REQUEST,
+	LDAP_BACK_CFG_T_F,
+	LDAP_BACK_CFG_TLS,
+	LDAP_BACK_CFG_LAST_BOTH
+};
+
+/* Target attrs */
+enum {
+	LDAP_BACK_CFG_URI = LDAP_BACK_CFG_LAST_BOTH,
+	LDAP_BACK_CFG_IDASSERT_AUTHZFROM,
+	LDAP_BACK_CFG_IDASSERT_BIND,
+	LDAP_BACK_CFG_SUFFIXM,
+	LDAP_BACK_CFG_SUBTREE_EX,
+	LDAP_BACK_CFG_SUBTREE_IN,
+	LDAP_BACK_CFG_KEEPALIVE,
+	LDAP_BACK_CFG_FILTER,
+	LDAP_BACK_CFG_TCP_USER_TIMEOUT,
+	LDAP_BACK_CFG_LAST
+};
+
+static ConfigTable a_metacfg[] = {
+	{ "uri", "uri", 2, 0, 0,
+		ARG_MAGIC|LDAP_BACK_CFG_URI,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:0.14 "
+			"NAME 'olcDbURI' "
+			"DESC 'URI (list) for remote DSA' "
+			"SYNTAX OMsDirectoryString "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+	{ "tls", "what", 2, 0, 0,
+		ARG_MAGIC|LDAP_BACK_CFG_TLS,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.1 "
+			"NAME 'olcDbStartTLS' "
+			"DESC 'StartTLS' "
+			"SYNTAX OMsDirectoryString "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+	{ "idassert-bind", "args", 2, 0, 0,
+		ARG_MAGIC|LDAP_BACK_CFG_IDASSERT_BIND,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.7 "
+			"NAME 'olcDbIDAssertBind' "
+			"DESC 'Remote Identity Assertion administrative identity auth bind configuration' "
+			"SYNTAX OMsDirectoryString "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+	{ "idassert-authzFrom", "authzRule", 2, 2, 0,
+		ARG_MAGIC|LDAP_BACK_CFG_IDASSERT_AUTHZFROM,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.9 "
+			"NAME 'olcDbIDAssertAuthzFrom' "
+			"DESC 'Remote Identity Assertion authz rules' "
+			"EQUALITY caseIgnoreMatch "
+			"SYNTAX OMsDirectoryString "
+			"X-ORDERED 'VALUES' )",
+		NULL, NULL },
+	{ "rebind-as-user", "true|FALSE", 1, 2, 0,
+		ARG_MAGIC|ARG_ON_OFF|LDAP_BACK_CFG_REBIND,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.10 "
+			"NAME 'olcDbRebindAsUser' "
+			"DESC 'Rebind as user' "
+			"SYNTAX OMsBoolean "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+	{ "chase-referrals", "true|FALSE", 2, 2, 0,
+		ARG_MAGIC|ARG_ON_OFF|LDAP_BACK_CFG_CHASE,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.11 "
+			"NAME 'olcDbChaseReferrals' "
+			"DESC 'Chase referrals' "
+			"SYNTAX OMsBoolean "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+	{ "t-f-support", "true|FALSE|discover", 2, 2, 0,
+		ARG_MAGIC|LDAP_BACK_CFG_T_F,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.12 "
+			"NAME 'olcDbTFSupport' "
+			"DESC 'Absolute filters support' "
+			"SYNTAX OMsDirectoryString "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+	{ "timeout", "timeout(list)", 2, 0, 0,
+		ARG_MAGIC|LDAP_BACK_CFG_TIMEOUT,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.14 "
+			"NAME 'olcDbTimeout' "
+			"DESC 'Per-operation timeouts' "
+			"SYNTAX OMsDirectoryString "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+	{ "idle-timeout", "timeout", 2, 2, 0,
+		ARG_MAGIC|LDAP_BACK_CFG_IDLE_TIMEOUT,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.15 "
+			"NAME 'olcDbIdleTimeout' "
+			"DESC 'connection idle timeout' "
+			"SYNTAX OMsDirectoryString "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+	{ "network-timeout", "timeout", 2, 2, 0,
+		ARG_MAGIC|LDAP_BACK_CFG_NETWORK_TIMEOUT,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.17 "
+			"NAME 'olcDbNetworkTimeout' "
+			"DESC 'connection network timeout' "
+			"SYNTAX OMsDirectoryString "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+	{ "protocol-version", "version", 2, 2, 0,
+		ARG_MAGIC|ARG_INT|LDAP_BACK_CFG_VERSION,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.18 "
+			"NAME 'olcDbProtocolVersion' "
+			"DESC 'protocol version' "
+			"SYNTAX OMsInteger "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+
+	{ "cancel", "ABANDON|ignore|exop", 2, 2, 0,
+		ARG_MAGIC|LDAP_BACK_CFG_CANCEL,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.20 "
+			"NAME 'olcDbCancel' "
+			"DESC 'abandon/ignore/exop operations when appropriate' "
+			"SYNTAX OMsDirectoryString "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+	{ "quarantine", "retrylist", 2, 2, 0,
+		ARG_MAGIC|LDAP_BACK_CFG_QUARANTINE,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.21 "
+			"NAME 'olcDbQuarantine' "
+			"DESC 'Quarantine database if connection fails and retry according to rule' "
+			"SYNTAX OMsDirectoryString "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+
+	{ "conn-pool-max", "<n>", 2, 2, 0,
+		ARG_MAGIC|ARG_INT|LDAP_BACK_CFG_CONNPOOLMAX,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.23 "
+			"NAME 'olcDbConnectionPoolMax' "
+			"DESC 'Max size of privileged connections pool' "
+			"SYNTAX OMsInteger "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+#ifdef SLAP_CONTROL_X_SESSION_TRACKING
+	{ "session-tracking-request", "true|FALSE", 2, 2, 0,
+		ARG_MAGIC|ARG_ON_OFF|LDAP_BACK_CFG_ST_REQUEST,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.24 "
+			"NAME 'olcDbSessionTrackingRequest' "
+			"DESC 'Add session tracking control to proxied requests' "
+			"SYNTAX OMsBoolean "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+#endif /* SLAP_CONTROL_X_SESSION_TRACKING */
+	{ "norefs", "true|FALSE", 2, 2, 0,
+		ARG_MAGIC|ARG_ON_OFF|LDAP_BACK_CFG_NOREFS,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.25 "
+			"NAME 'olcDbNoRefs' "
+			"DESC 'Do not return search reference responses' "
+			"SYNTAX OMsBoolean "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+	{ "noundeffilter", "true|FALSE", 2, 2, 0,
+		ARG_MAGIC|ARG_ON_OFF|LDAP_BACK_CFG_NOUNDEFFILTER,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.26 "
+			"NAME 'olcDbNoUndefFilter' "
+			"DESC 'Do not propagate undefined search filters' "
+			"SYNTAX OMsBoolean "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+
+	{ "suffixmassage", "local> <remote", 2, 3, 0,
+		ARG_MAGIC|LDAP_BACK_CFG_SUFFIXM,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.117 "
+			"NAME 'olcDbSuffixMassage' "
+			"DESC 'DN suffix massage' "
+			"EQUALITY caseIgnoreMatch "
+			"SYNTAX OMsDirectoryString "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+
+	{ "subtree-exclude", "pattern", 2, 2, 0,
+		ARG_MAGIC|LDAP_BACK_CFG_SUBTREE_EX,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.103 "
+			"NAME 'olcDbSubtreeExclude' "
+			"DESC 'DN of subtree to exclude from target' "
+			"EQUALITY caseIgnoreMatch "
+			"SYNTAX OMsDirectoryString )",
+		NULL, NULL },
+	{ "subtree-include", "pattern", 2, 2, 0,
+		ARG_MAGIC|LDAP_BACK_CFG_SUBTREE_IN,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.104 "
+			"NAME 'olcDbSubtreeInclude' "
+			"DESC 'DN of subtree to include in target' "
+			"EQUALITY caseIgnoreMatch "
+			"SYNTAX OMsDirectoryString )",
+		NULL, NULL },
+	{ "default-target", "[none|<target ID>]", 1, 2, 0,
+		ARG_MAGIC|LDAP_BACK_CFG_DEFAULT_T,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.105 "
+			"NAME 'olcDbDefaultTarget' "
+			"DESC 'Specify the default target' "
+			"SYNTAX OMsDirectoryString "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+	{ "dncache-ttl", "ttl", 2, 2, 0,
+		ARG_MAGIC|LDAP_BACK_CFG_DNCACHE_TTL,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.106 "
+			"NAME 'olcDbDnCacheTtl' "
+			"DESC 'dncache ttl' "
+			"SYNTAX OMsDirectoryString "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+	{ "bind-timeout", "microseconds", 2, 2, 0,
+		ARG_MAGIC|ARG_ULONG|LDAP_BACK_CFG_BIND_TIMEOUT,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.107 "
+			"NAME 'olcDbBindTimeout' "
+			"DESC 'bind timeout' "
+			"SYNTAX OMsDirectoryString "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+	{ "onerr", "CONTINUE|report|stop", 2, 2, 0,
+		ARG_MAGIC|LDAP_BACK_CFG_ONERR,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.108 "
+			"NAME 'olcDbOnErr' "
+			"DESC 'error handling' "
+			"SYNTAX OMsDirectoryString "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+	{ "pseudoroot-bind-defer", "TRUE|false", 2, 2, 0,
+		ARG_MAGIC|ARG_ON_OFF|LDAP_BACK_CFG_PSEUDOROOT_BIND_DEFER,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.109 "
+			"NAME 'olcDbPseudoRootBindDefer' "
+			"DESC 'error handling' "
+			"SYNTAX OMsBoolean "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+	{ "root-bind-defer", "TRUE|false", 2, 2, 0,
+		ARG_MAGIC|ARG_ON_OFF|LDAP_BACK_CFG_PSEUDOROOT_BIND_DEFER,
+		asyncmeta_back_cf_gen, NULL, NULL, NULL },
+	{ "nretries", "NEVER|forever|<number>", 2, 2, 0,
+		ARG_MAGIC|LDAP_BACK_CFG_NRETRIES,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.110 "
+			"NAME 'olcDbNretries' "
+			"DESC 'retry handling' "
+			"SYNTAX OMsDirectoryString "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+	{ "client-pr", "accept-unsolicited|disable|<size>", 2, 2, 0,
+		ARG_MAGIC|LDAP_BACK_CFG_CLIENT_PR,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.111 "
+			"NAME 'olcDbClientPr' "
+			"DESC 'PagedResults handling' "
+			"SYNTAX OMsDirectoryString "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+
+	{ "", "", 0, 0, 0, ARG_IGNORED,
+		NULL, "( OLcfgDbAt:3.116 NAME 'olcAsyncMetaSub' "
+			"DESC 'Placeholder to name a Target entry' "
+			"EQUALITY caseIgnoreMatch "
+			"SYNTAX OMsDirectoryString "
+			"SINGLE-VALUE X-ORDERED 'SIBLINGS' )", NULL, NULL },
+
+	{ "keepalive", "keepalive", 2, 2, 0,
+		ARG_MAGIC|LDAP_BACK_CFG_KEEPALIVE,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.29 "
+			"NAME 'olcDbKeepalive' "
+			"DESC 'TCP keepalive' "
+			"SYNTAX OMsDirectoryString "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+
+	{ "tcp-user-timeout", "milliseconds", 2, 2, 0,
+		ARG_MAGIC|ARG_UINT|LDAP_BACK_CFG_TCP_USER_TIMEOUT,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.30 "
+			"NAME 'olcDbTcpUserTimeout' "
+			"DESC 'TCP User Timeout' "
+			"SYNTAX OMsInteger "
+			"SINGLE-VALUE )",
+		NULL, NULL },
+
+	{ "filter", "pattern", 2, 2, 0,
+		ARG_MAGIC|LDAP_BACK_CFG_FILTER,
+		asyncmeta_back_cf_gen, "( OLcfgDbAt:3.112 "
+			"NAME 'olcDbFilter' "
+			"DESC 'Filter regex pattern to include in target' "
+			"EQUALITY caseExactMatch "
+			"SYNTAX OMsDirectoryString )",
+		NULL, NULL },
+
+	{ "max-pending-ops", "<n>", 2, 2, 0,
+	  ARG_MAGIC|ARG_INT|LDAP_BACK_CFG_MAX_PENDING_OPS,
+	  asyncmeta_back_cf_gen, "( OLcfgDbAt:3.113 "
+	  "NAME 'olcDbMaxPendingOps' "
+	  "DESC 'Maximum number of pending operations' "
+	  "SYNTAX OMsInteger "
+	  "SINGLE-VALUE )",
+	  NULL, NULL },
+
+	{ "max-target-conns", "<n>", 2, 2, 0,
+	  ARG_MAGIC|ARG_INT|LDAP_BACK_CFG_MAX_TARGET_CONNS,
+	  asyncmeta_back_cf_gen, "( OLcfgDbAt:3.114 "
+	  "NAME 'olcDbMaxTargetConns' "
+	  "DESC 'Maximum number of open connections per target' "
+	  "SYNTAX OMsInteger "
+	  "SINGLE-VALUE )",
+	  NULL, NULL },
+
+	{ "max-timeout-ops", "<n>", 2, 2, 0,
+	  ARG_MAGIC|ARG_INT|LDAP_BACK_CFG_MAX_TIMEOUT_OPS,
+	  asyncmeta_back_cf_gen, "( OLcfgDbAt:3.115 "
+	  "NAME 'olcDbMaxTimeoutOps' "
+	  "DESC 'Maximum number of consecutive timeout operations after which the connection is reset' "
+	  "SYNTAX OMsInteger "
+	  "SINGLE-VALUE )",
+	  NULL, NULL },
+
+	{ NULL, NULL, 0, 0, 0, ARG_IGNORED,
+		NULL, NULL, NULL, NULL }
+};
+
+#ifdef SLAP_CONTROL_X_SESSION_TRACKING
+#define	ST_ATTR "$ olcDbSessionTrackingRequest "
+#else
+#define	ST_ATTR ""
+#endif /* SLAP_CONTROL_X_SESSION_TRACKING */
+
+#define COMMON_ATTRS	\
+			"$ olcDbBindTimeout " \
+			"$ olcDbCancel " \
+			"$ olcDbChaseReferrals " \
+			"$ olcDbClientPr " \
+			"$ olcDbDefaultTarget " \
+			"$ olcDbNetworkTimeout " \
+			"$ olcDbNoRefs " \
+			"$ olcDbNoUndefFilter " \
+			"$ olcDbNretries " \
+			"$ olcDbProtocolVersion " \
+			"$ olcDbQuarantine " \
+			"$ olcDbRebindAsUser " \
+			ST_ATTR \
+			"$ olcDbStartTLS " \
+			"$ olcDbTFSupport "
+
+static ConfigOCs a_metaocs[] = {
+	{ "( OLcfgDbOc:3.4 "
+		"NAME 'olcAsyncMetaConfig' "
+		"DESC 'Asyncmeta backend configuration' "
+		"SUP olcDatabaseConfig "
+		"MAY ( olcDbDnCacheTtl "
+			"$ olcDbIdleTimeout "
+			"$ olcDbOnErr "
+			"$ olcDbPseudoRootBindDefer "
+			"$ olcDbConnectionPoolMax "
+	                "$ olcDbMaxTimeoutOps"
+	                "$ olcDbMaxPendingOps "
+	                "$ olcDbMaxTargetConns"
+			/* defaults, may be overridden per-target */
+			COMMON_ATTRS
+		") )",
+			Cft_Database, a_metacfg, NULL, asyncmeta_cfadd },
+	{ "( OLcfgDbOc:3.5 "
+		"NAME 'olcAsyncMetaTargetConfig' "
+		"DESC 'Asyncmeta target configuration' "
+		"SUP olcConfig STRUCTURAL "
+		"MUST ( olcAsyncMetaSub $ olcDbURI ) "
+		"MAY ( olcDbIDAssertAuthzFrom "
+			"$ olcDbIDAssertBind "
+			"$ olcDbSuffixMassage "
+			"$ olcDbSubtreeExclude "
+			"$ olcDbSubtreeInclude "
+			"$ olcDbTimeout "
+			"$ olcDbKeepalive "
+			"$ olcDbFilter "
+			"$ olcDbTcpUserTimeout "
+
+			/* defaults may be inherited */
+			COMMON_ATTRS
+		") )",
+			Cft_Misc, a_metacfg, asyncmeta_ldadd },
+	{ NULL, 0, NULL }
+};
+
+static int
+asyncmeta_ldadd( CfEntryInfo *p, Entry *e, ConfigArgs *c )
+{
+	if ( p->ce_type != Cft_Database || !p->ce_be ||
+		p->ce_be->be_cf_ocs != a_metaocs )
+		return LDAP_CONSTRAINT_VIOLATION;
+
+	c->be = p->ce_be;
+	return LDAP_SUCCESS;
+}
+
+static int
+asyncmeta_cfadd( Operation *op, SlapReply *rs, Entry *p, ConfigArgs *c )
+{
+	a_metainfo_t	*mi = ( a_metainfo_t * )c->be->be_private;
+	struct berval bv;
+	int i;
+
+	bv.bv_val = c->cr_msg;
+	for ( i=0; i<mi->mi_ntargets; i++ ) {
+		bv.bv_len = snprintf( c->cr_msg, sizeof(c->cr_msg),
+			"olcAsyncMetaSub=" SLAP_X_ORDERED_FMT "uri", i );
+		c->ca_private = mi->mi_targets[i];
+		c->valx = i;
+		config_build_entry( op, rs, p->e_private, c,
+			&bv, &a_metaocs[1], NULL );
+	}
+
+	return LDAP_SUCCESS;
+}
+
+static int
+asyncmeta_back_new_target(
+	a_metatarget_t	**mtp )
+{
+	a_metatarget_t		*mt;
+
+	*mtp = NULL;
+
+	mt = ch_calloc( sizeof( a_metatarget_t ), 1 );
+
+	ldap_pvt_thread_mutex_init( &mt->mt_uri_mutex );
+
+	mt->mt_idassert_mode = LDAP_BACK_IDASSERT_LEGACY;
+	mt->mt_idassert_authmethod = LDAP_AUTH_NONE;
+	mt->mt_idassert_tls = SB_TLS_DEFAULT;
+	/* by default, use proxyAuthz control on each operation */
+	mt->mt_idassert_flags = LDAP_BACK_AUTH_PRESCRIPTIVE;
+
+	*mtp = mt;
+
+	return 0;
+}
+
+/* suffixmassage config */
+static int
+asyncmeta_suffixm_config(
+	ConfigArgs *c,
+	int argc,
+	char **argv,
+	a_metatarget_t *mt
+)
+{
+	BackendDB 	*tmp_bd;
+	struct berval	dn, nvnc, pvnc, nrnc, prnc;
+	int j;
+
+	/*
+	 * syntax:
+	 *
+	 * 	suffixmassage <local suffix> <remote suffix>
+	 *
+	 * the <local suffix> field must be defined as a valid suffix
+	 * (or suffixAlias?) for the current database;
+	 * the <remote suffix> shouldn't have already been
+	 * defined as a valid suffix or suffixAlias for the
+	 * current server
+	 */
+
+	ber_str2bv( argv[ 1 ], 0, 0, &dn );
+	if ( dnPrettyNormal( NULL, &dn, &pvnc, &nvnc, NULL ) != LDAP_SUCCESS ) {
+		snprintf( c->cr_msg, sizeof( c->cr_msg ),
+			"suffix \"%s\" is invalid",
+			argv[1] );
+		Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+		return 1;
+	}
+
+	for ( j = 0; !BER_BVISNULL( &c->be->be_nsuffix[ j ] ); j++ ) {
+		if ( dnIsSuffix( &nvnc, &c->be->be_nsuffix[ 0 ] ) ) {
+			break;
+		}
+	}
+
+	if ( BER_BVISNULL( &c->be->be_nsuffix[ j ] ) ) {
+		snprintf( c->cr_msg, sizeof( c->cr_msg ),
+			"suffix \"%s\" must be within the database naming context",
+			argv[1] );
+		Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+		free( pvnc.bv_val );
+		free( nvnc.bv_val );
+		return 1;
+	}
+
+	ber_str2bv( argv[ 2 ], 0, 0, &dn );
+	if ( dnPrettyNormal( NULL, &dn, &prnc, &nrnc, NULL ) != LDAP_SUCCESS ) {
+		snprintf( c->cr_msg, sizeof( c->cr_msg ),
+			"massaged suffix \"%s\" is invalid",
+			argv[2] );
+		Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+		free( pvnc.bv_val );
+		free( nvnc.bv_val );
+		return 1;
+	}
+
+	tmp_bd = select_backend( &nrnc, 0 );
+	if ( tmp_bd != NULL && tmp_bd->be_private == c->be->be_private ) {
+		Debug( LDAP_DEBUG_ANY,
+	"%s: warning: <massaged suffix> \"%s\" resolves to this database, in "
+	"\"suffixMassage <suffix> <massaged suffix>\"\n",
+			c->log, prnc.bv_val );
+	}
+
+	mt->mt_lsuffixm = pvnc;
+	mt->mt_rsuffixm = prnc;
+
+	free( nvnc.bv_val );
+	free( nrnc.bv_val );
+
+	return 0;
+}
+
+int
+asyncmeta_subtree_free( a_metasubtree_t *ms )
+{
+	switch ( ms->ms_type ) {
+	case META_ST_SUBTREE:
+	case META_ST_SUBORDINATE:
+		ber_memfree( ms->ms_dn.bv_val );
+		break;
+
+	case META_ST_REGEX:
+		regfree( &ms->ms_regex );
+		ber_memfree( ms->ms_regex_pattern.bv_val );
+		break;
+
+	default:
+		return -1;
+	}
+
+	ch_free( ms );
+	return 0;
+}
+
+int
+asyncmeta_subtree_destroy( a_metasubtree_t *ms )
+{
+	if ( ms->ms_next ) {
+		asyncmeta_subtree_destroy( ms->ms_next );
+	}
+
+	return asyncmeta_subtree_free( ms );
+}
+
+static void
+asyncmeta_filter_free( metafilter_t *mf )
+{
+	regfree( &mf->mf_regex );
+	ber_memfree( mf->mf_regex_pattern.bv_val );
+	ch_free( mf );
+}
+
+void
+asyncmeta_filter_destroy( metafilter_t *mf )
+{
+	if ( mf->mf_next )
+		asyncmeta_filter_destroy( mf->mf_next );
+	asyncmeta_filter_free( mf );
+}
+
+static struct berval st_styles[] = {
+	BER_BVC("subtree"),
+	BER_BVC("children"),
+	BER_BVC("regex")
+};
+
+static int
+asyncmeta_subtree_unparse(
+	ConfigArgs *c,
+	a_metatarget_t *mt )
+{
+	a_metasubtree_t	*ms;
+	struct berval bv, *style;
+
+	if ( !mt->mt_subtree )
+		return 1;
+
+	/* can only be one of exclude or include */
+	if (( c->type == LDAP_BACK_CFG_SUBTREE_EX ) ^ mt->mt_subtree_exclude )
+		return 1;
+
+	bv.bv_val = c->cr_msg;
+	for ( ms=mt->mt_subtree; ms; ms=ms->ms_next ) {
+		if (ms->ms_type == META_ST_SUBTREE)
+			style = &st_styles[0];
+		else if ( ms->ms_type == META_ST_SUBORDINATE )
+			style = &st_styles[1];
+		else if ( ms->ms_type == META_ST_REGEX )
+			style = &st_styles[2];
+		else {
+			assert(0);
+			continue;
+		}
+		bv.bv_len = snprintf( c->cr_msg, sizeof(c->cr_msg),
+			"dn.%s:%s", style->bv_val, ms->ms_dn.bv_val );
+		value_add_one( &c->rvalue_vals, &bv );
+	}
+	return 0;
+}
+
+static int
+asyncmeta_subtree_config(
+	a_metatarget_t *mt,
+	ConfigArgs *c )
+{
+	meta_st_t	type = META_ST_SUBTREE;
+	char		*pattern;
+	struct berval	ndn = BER_BVNULL;
+	a_metasubtree_t	*ms = NULL;
+
+	if ( c->type == LDAP_BACK_CFG_SUBTREE_EX ) {
+		if ( mt->mt_subtree && !mt->mt_subtree_exclude ) {
+			snprintf( c->cr_msg, sizeof(c->cr_msg),
+				"\"subtree-exclude\" incompatible with previous \"subtree-include\" directives" );
+			return 1;
+		}
+
+		mt->mt_subtree_exclude = 1;
+
+	} else {
+		if ( mt->mt_subtree && mt->mt_subtree_exclude ) {
+			snprintf( c->cr_msg, sizeof(c->cr_msg),
+				"\"subtree-include\" incompatible with previous \"subtree-exclude\" directives" );
+			return 1;
+		}
+	}
+
+	pattern = c->argv[1];
+	if ( strncasecmp( pattern, "dn", STRLENOF( "dn" ) ) == 0 ) {
+		char *style;
+
+		pattern = &pattern[STRLENOF( "dn")];
+
+		if ( pattern[0] == '.' ) {
+			style = &pattern[1];
+
+			if ( strncasecmp( style, "subtree", STRLENOF( "subtree" ) ) == 0 ) {
+				type = META_ST_SUBTREE;
+				pattern = &style[STRLENOF( "subtree" )];
+
+			} else if ( strncasecmp( style, "children", STRLENOF( "children" ) ) == 0 ) {
+				type = META_ST_SUBORDINATE;
+				pattern = &style[STRLENOF( "children" )];
+
+			} else if ( strncasecmp( style, "sub", STRLENOF( "sub" ) ) == 0 ) {
+				type = META_ST_SUBTREE;
+				pattern = &style[STRLENOF( "sub" )];
+
+			} else if ( strncasecmp( style, "regex", STRLENOF( "regex" ) ) == 0 ) {
+				type = META_ST_REGEX;
+				pattern = &style[STRLENOF( "regex" )];
+
+			} else {
+				snprintf( c->cr_msg, sizeof(c->cr_msg), "unknown style in \"dn.<style>\"" );
+				return 1;
+			}
+		}
+
+		if ( pattern[0] != ':' ) {
+			snprintf( c->cr_msg, sizeof(c->cr_msg), "missing colon after \"dn.<style>\"" );
+			return 1;
+		}
+		pattern++;
+	}
+
+	switch ( type ) {
+	case META_ST_SUBTREE:
+	case META_ST_SUBORDINATE: {
+		struct berval dn;
+
+		ber_str2bv( pattern, 0, 0, &dn );
+		if ( dnNormalize( 0, NULL, NULL, &dn, &ndn, NULL )
+			!= LDAP_SUCCESS )
+		{
+			snprintf( c->cr_msg, sizeof(c->cr_msg), "DN=\"%s\" is invalid", pattern );
+			return 1;
+		}
+
+		if ( !dnIsSuffix( &ndn, &mt->mt_nsuffix ) ) {
+			snprintf( c->cr_msg, sizeof(c->cr_msg),
+				"DN=\"%s\" is not a subtree of target \"%s\"",
+				pattern, mt->mt_nsuffix.bv_val );
+			ber_memfree( ndn.bv_val );
+			return( 1 );
+		}
+		} break;
+
+	default:
+		/* silence warnings */
+		break;
+	}
+
+	ms = ch_calloc( sizeof( a_metasubtree_t ), 1 );
+	ms->ms_type = type;
+
+	switch ( ms->ms_type ) {
+	case META_ST_SUBTREE:
+	case META_ST_SUBORDINATE:
+		ms->ms_dn = ndn;
+		break;
+
+	case META_ST_REGEX: {
+		int rc;
+
+		rc = regcomp( &ms->ms_regex, pattern, REG_EXTENDED|REG_ICASE );
+		if ( rc != 0 ) {
+			char regerr[ SLAP_TEXT_BUFLEN ];
+
+			regerror( rc, &ms->ms_regex, regerr, sizeof(regerr) );
+
+			snprintf( c->cr_msg, sizeof( c->cr_msg ),
+				"regular expression \"%s\" bad because of %s",
+				pattern, regerr );
+			ch_free( ms );
+			return 1;
+		}
+		ber_str2bv( pattern, 0, 1, &ms->ms_regex_pattern );
+		} break;
+	}
+
+	if ( mt->mt_subtree == NULL ) {
+		 mt->mt_subtree = ms;
+
+	} else {
+		a_metasubtree_t **msp;
+
+		for ( msp = &mt->mt_subtree; *msp; ) {
+			switch ( ms->ms_type ) {
+			case META_ST_SUBTREE:
+				switch ( (*msp)->ms_type ) {
+				case META_ST_SUBTREE:
+					if ( dnIsSuffix( &(*msp)->ms_dn, &ms->ms_dn ) ) {
+						a_metasubtree_t *tmp = *msp;
+						Debug( LDAP_DEBUG_CONFIG,
+							"%s: previous rule \"dn.subtree:%s\" is contained in rule \"dn.subtree:%s\" (replaced)\n",
+							c->log, pattern, (*msp)->ms_dn.bv_val );
+						*msp = (*msp)->ms_next;
+						tmp->ms_next = NULL;
+						asyncmeta_subtree_destroy( tmp );
+						continue;
+
+					} else if ( dnIsSuffix( &ms->ms_dn, &(*msp)->ms_dn ) ) {
+						Debug( LDAP_DEBUG_CONFIG,
+							"%s: previous rule \"dn.subtree:%s\" contains rule \"dn.subtree:%s\" (ignored)\n",
+							c->log, (*msp)->ms_dn.bv_val, pattern );
+						asyncmeta_subtree_destroy( ms );
+						ms = NULL;
+						return( 0 );
+					}
+					break;
+
+				case META_ST_SUBORDINATE:
+					if ( dnIsSuffix( &(*msp)->ms_dn, &ms->ms_dn ) ) {
+						a_metasubtree_t *tmp = *msp;
+						Debug( LDAP_DEBUG_CONFIG,
+							"%s: previous rule \"dn.children:%s\" is contained in rule \"dn.subtree:%s\" (replaced)\n",
+							c->log, pattern, (*msp)->ms_dn.bv_val );
+						*msp = (*msp)->ms_next;
+						tmp->ms_next = NULL;
+						asyncmeta_subtree_destroy( tmp );
+						continue;
+
+					} else if ( dnIsSuffix( &ms->ms_dn, &(*msp)->ms_dn ) && ms->ms_dn.bv_len > (*msp)->ms_dn.bv_len ) {
+						Debug( LDAP_DEBUG_CONFIG,
+							"%s: previous rule \"dn.children:%s\" contains rule \"dn.subtree:%s\" (ignored)\n",
+							c->log, (*msp)->ms_dn.bv_val, pattern );
+						asyncmeta_subtree_destroy( ms );
+						ms = NULL;
+						return( 0 );
+					}
+					break;
+
+				case META_ST_REGEX:
+					if ( regexec( &(*msp)->ms_regex, ms->ms_dn.bv_val, 0, NULL, 0 ) == 0 ) {
+						Debug( LDAP_DEBUG_CONFIG,
+							"%s: previous rule \"dn.regex:%s\" may contain rule \"dn.subtree:%s\"\n",
+							c->log, (*msp)->ms_regex_pattern.bv_val, ms->ms_dn.bv_val );
+					}
+					break;
+				}
+				break;
+
+			case META_ST_SUBORDINATE:
+				switch ( (*msp)->ms_type ) {
+				case META_ST_SUBTREE:
+					if ( dnIsSuffix( &(*msp)->ms_dn, &ms->ms_dn ) ) {
+						a_metasubtree_t *tmp = *msp;
+						Debug( LDAP_DEBUG_CONFIG,
+							"%s: previous rule \"dn.children:%s\" is contained in rule \"dn.subtree:%s\" (replaced)\n",
+							c->log, pattern, (*msp)->ms_dn.bv_val );
+						*msp = (*msp)->ms_next;
+						tmp->ms_next = NULL;
+						asyncmeta_subtree_destroy( tmp );
+						continue;
+
+					} else if ( dnIsSuffix( &ms->ms_dn, &(*msp)->ms_dn ) && ms->ms_dn.bv_len > (*msp)->ms_dn.bv_len ) {
+						Debug( LDAP_DEBUG_CONFIG,
+							"%s: previous rule \"dn.children:%s\" contains rule \"dn.subtree:%s\" (ignored)\n",
+							c->log, (*msp)->ms_dn.bv_val, pattern );
+						asyncmeta_subtree_destroy( ms );
+						ms = NULL;
+						return( 0 );
+					}
+					break;
+
+				case META_ST_SUBORDINATE:
+					if ( dnIsSuffix( &(*msp)->ms_dn, &ms->ms_dn ) ) {
+						a_metasubtree_t *tmp = *msp;
+						Debug( LDAP_DEBUG_CONFIG,
+							"%s: previous rule \"dn.children:%s\" is contained in rule \"dn.children:%s\" (replaced)\n",
+							c->log, pattern, (*msp)->ms_dn.bv_val );
+						*msp = (*msp)->ms_next;
+						tmp->ms_next = NULL;
+						asyncmeta_subtree_destroy( tmp );
+						continue;
+
+					} else if ( dnIsSuffix( &ms->ms_dn, &(*msp)->ms_dn ) ) {
+						Debug( LDAP_DEBUG_CONFIG,
+							"%s: previous rule \"dn.children:%s\" contains rule \"dn.children:%s\" (ignored)\n",
+							c->log, (*msp)->ms_dn.bv_val, pattern );
+						asyncmeta_subtree_destroy( ms );
+						ms = NULL;
+						return( 0 );
+					}
+					break;
+
+				case META_ST_REGEX:
+					if ( regexec( &(*msp)->ms_regex, ms->ms_dn.bv_val, 0, NULL, 0 ) == 0 ) {
+						Debug( LDAP_DEBUG_CONFIG,
+							"%s: previous rule \"dn.regex:%s\" may contain rule \"dn.subtree:%s\"\n",
+							c->log, (*msp)->ms_regex_pattern.bv_val, ms->ms_dn.bv_val );
+					}
+					break;
+				}
+				break;
+
+			case META_ST_REGEX:
+				switch ( (*msp)->ms_type ) {
+				case META_ST_SUBTREE:
+				case META_ST_SUBORDINATE:
+					if ( regexec( &ms->ms_regex, (*msp)->ms_dn.bv_val, 0, NULL, 0 ) == 0 ) {
+						Debug( LDAP_DEBUG_CONFIG,
+							"%s: previous rule \"dn.subtree:%s\" may be contained in rule \"dn.regex:%s\"\n",
+							c->log, (*msp)->ms_dn.bv_val, ms->ms_regex_pattern.bv_val );
+					}
+					break;
+
+				case META_ST_REGEX:
+					/* no check possible */
+					break;
+				}
+				break;
+			}
+
+			msp = &(*msp)->ms_next;
+		}
+
+		*msp = ms;
+	}
+
+	return 0;
+}
+
+static slap_verbmasks idassert_mode[] = {
+	{ BER_BVC("self"),		LDAP_BACK_IDASSERT_SELF },
+	{ BER_BVC("anonymous"),		LDAP_BACK_IDASSERT_ANONYMOUS },
+	{ BER_BVC("none"),		LDAP_BACK_IDASSERT_NOASSERT },
+	{ BER_BVC("legacy"),		LDAP_BACK_IDASSERT_LEGACY },
+	{ BER_BVNULL,			0 }
+};
+
+static slap_verbmasks tls_mode[] = {
+	{ BER_BVC( "propagate" ),	LDAP_BACK_F_TLS_PROPAGATE_MASK },
+	{ BER_BVC( "try-propagate" ),	LDAP_BACK_F_PROPAGATE_TLS },
+	{ BER_BVC( "start" ),		LDAP_BACK_F_TLS_USE_MASK },
+	{ BER_BVC( "try-start" ),	LDAP_BACK_F_USE_TLS },
+	{ BER_BVC( "ldaps" ),		LDAP_BACK_F_TLS_LDAPS },
+	{ BER_BVC( "none" ),		LDAP_BACK_F_NONE },
+	{ BER_BVNULL,			0 }
+};
+
+static slap_verbmasks t_f_mode[] = {
+	{ BER_BVC( "yes" ),		LDAP_BACK_F_T_F },
+	{ BER_BVC( "discover" ),	LDAP_BACK_F_T_F_DISCOVER },
+	{ BER_BVC( "no" ),		LDAP_BACK_F_NONE },
+	{ BER_BVNULL,			0 }
+};
+
+static slap_verbmasks cancel_mode[] = {
+	{ BER_BVC( "ignore" ),		LDAP_BACK_F_CANCEL_IGNORE },
+	{ BER_BVC( "exop" ),		LDAP_BACK_F_CANCEL_EXOP },
+	{ BER_BVC( "exop-discover" ),	LDAP_BACK_F_CANCEL_EXOP_DISCOVER },
+	{ BER_BVC( "abandon" ),		LDAP_BACK_F_CANCEL_ABANDON },
+	{ BER_BVNULL,			0 }
+};
+
+static slap_verbmasks onerr_mode[] = {
+	{ BER_BVC( "stop" ),		META_BACK_F_ONERR_STOP },
+	{ BER_BVC( "report" ),	META_BACK_F_ONERR_REPORT },
+	{ BER_BVC( "continue" ),		LDAP_BACK_F_NONE },
+	{ BER_BVNULL,			0 }
+};
+
+/* see enum in slap.h */
+static slap_cf_aux_table timeout_table[] = {
+	{ BER_BVC("bind="),	SLAP_OP_BIND * sizeof( time_t ),	'u', 0, NULL },
+	/* unbind makes no sense */
+	{ BER_BVC("add="),	SLAP_OP_ADD * sizeof( time_t ),		'u', 0, NULL },
+	{ BER_BVC("delete="),	SLAP_OP_DELETE * sizeof( time_t ),	'u', 0, NULL },
+	{ BER_BVC("modrdn="),	SLAP_OP_MODRDN * sizeof( time_t ),	'u', 0, NULL },
+	{ BER_BVC("modify="),	SLAP_OP_MODIFY * sizeof( time_t ),	'u', 0, NULL },
+	{ BER_BVC("compare="),	SLAP_OP_COMPARE * sizeof( time_t ),	'u', 0, NULL },
+	{ BER_BVC("search="),	SLAP_OP_SEARCH * sizeof( time_t ),	'u', 0, NULL },
+	/* abandon makes little sense */
+#if 0	/* not implemented yet */
+	{ BER_BVC("extended="),	SLAP_OP_EXTENDED * sizeof( time_t ),	'u', 0, NULL },
+#endif
+	{ BER_BVNULL, 0, 0, 0, NULL }
+};
+
+static int
+asyncmeta_cf_cleanup( ConfigArgs *c )
+{
+	a_metainfo_t	*mi = ( a_metainfo_t * )c->be->be_private;
+	a_metatarget_t	*mt = c->ca_private;
+
+	return asyncmeta_target_finish( mi, mt, c->log, c->cr_msg, sizeof( c->cr_msg ));
+}
+
+static int
+asyncmeta_back_cf_gen( ConfigArgs *c )
+{
+	a_metainfo_t	*mi = ( a_metainfo_t * )c->be->be_private;
+	a_metatarget_t	*mt = NULL;
+	a_metacommon_t	*mc = NULL;
+
+	int i, rc = 0;
+
+	assert( mi != NULL );
+
+	if ( c->op == SLAP_CONFIG_EMIT || c->op == LDAP_MOD_DELETE ) {
+		if ( !mi )
+			return 1;
+
+		if ( c->table == Cft_Database ) {
+			mt = NULL;
+			mc = &mi->mi_mc;
+		} else {
+			mt = c->ca_private;
+			mc = &mt->mt_mc;
+		}
+	}
+
+	if ( c->op == SLAP_CONFIG_EMIT ) {
+		struct berval bv = BER_BVNULL;
+
+		switch( c->type ) {
+		/* Base attrs */
+
+		case LDAP_BACK_CFG_DNCACHE_TTL:
+			if ( mi->mi_cache.ttl == META_DNCACHE_DISABLED ) {
+				return 1;
+			} else if ( mi->mi_cache.ttl == META_DNCACHE_FOREVER ) {
+				BER_BVSTR( &bv, "forever" );
+			} else {
+				char	buf[ SLAP_TEXT_BUFLEN ];
+
+				lutil_unparse_time( buf, sizeof( buf ), mi->mi_cache.ttl );
+				ber_str2bv( buf, 0, 0, &bv );
+			}
+			value_add_one( &c->rvalue_vals, &bv );
+			break;
+
+		case LDAP_BACK_CFG_IDLE_TIMEOUT:
+			if ( mi->mi_idle_timeout == 0 ) {
+				return 1;
+			} else {
+				char	buf[ SLAP_TEXT_BUFLEN ];
+
+				lutil_unparse_time( buf, sizeof( buf ), mi->mi_idle_timeout );
+				ber_str2bv( buf, 0, 0, &bv );
+				value_add_one( &c->rvalue_vals, &bv );
+			}
+			break;
+
+		case LDAP_BACK_CFG_ONERR:
+			enum_to_verb( onerr_mode, mi->mi_flags & META_BACK_F_ONERR_MASK, &bv );
+			if ( BER_BVISNULL( &bv )) {
+				rc = 1;
+			} else {
+				value_add_one( &c->rvalue_vals, &bv );
+			}
+			break;
+
+		case LDAP_BACK_CFG_PSEUDOROOT_BIND_DEFER:
+			c->value_int = META_BACK_DEFER_ROOTDN_BIND( mi );
+			break;
+
+		case LDAP_BACK_CFG_CONNPOOLMAX:
+			c->value_int = mi->mi_conn_priv_max;
+			break;
+
+		/* common attrs */
+		case LDAP_BACK_CFG_BIND_TIMEOUT:
+			if ( mc->mc_bind_timeout.tv_sec == 0 &&
+				mc->mc_bind_timeout.tv_usec == 0 ) {
+				return 1;
+			} else {
+				c->value_ulong = mc->mc_bind_timeout.tv_sec * 1000000UL +
+					mc->mc_bind_timeout.tv_usec;
+			}
+			break;
+
+		case LDAP_BACK_CFG_CANCEL: {
+			slap_mask_t	mask = LDAP_BACK_F_CANCEL_MASK2;
+
+			if ( mt && META_BACK_TGT_CANCEL_DISCOVER( mt ) ) {
+				mask &= ~LDAP_BACK_F_CANCEL_EXOP;
+			}
+			enum_to_verb( cancel_mode, (mc->mc_flags & mask), &bv );
+			if ( BER_BVISNULL( &bv ) ) {
+				/* there's something wrong... */
+				assert( 0 );
+				rc = 1;
+
+			} else {
+				value_add_one( &c->rvalue_vals, &bv );
+			}
+			} break;
+
+		case LDAP_BACK_CFG_CHASE:
+			c->value_int = META_BACK_CMN_CHASE_REFERRALS(mc);
+			break;
+
+#ifdef SLAPD_META_CLIENT_PR
+		case LDAP_BACK_CFG_CLIENT_PR:
+			if ( mc->mc_ps == META_CLIENT_PR_DISABLE ) {
+				return 1;
+			} else if ( mc->mc_ps == META_CLIENT_PR_ACCEPT_UNSOLICITED ) {
+				BER_BVSTR( &bv, "accept-unsolicited" );
+			} else {
+				bv.bv_len = snprintf( c->cr_msg, sizeof(c->cr_msg), "%d", mc->mc_ps );
+				bv.bv_val = c->cr_msg;
+			}
+			value_add_one( &c->rvalue_vals, &bv );
+			break;
+#endif /* SLAPD_META_CLIENT_PR */
+
+		case LDAP_BACK_CFG_DEFAULT_T:
+			if ( mt || mi->mi_defaulttarget == META_DEFAULT_TARGET_NONE )
+				return 1;
+			bv.bv_len = snprintf( c->cr_msg, sizeof(c->cr_msg), "%d", mi->mi_defaulttarget );
+			bv.bv_val = c->cr_msg;
+			value_add_one( &c->rvalue_vals, &bv );
+			break;
+
+		case LDAP_BACK_CFG_NETWORK_TIMEOUT:
+			if ( mc->mc_network_timeout == 0 ) {
+				return 1;
+			}
+			bv.bv_len = snprintf( c->cr_msg, sizeof(c->cr_msg), "%ld",
+				mc->mc_network_timeout );
+			bv.bv_val = c->cr_msg;
+			value_add_one( &c->rvalue_vals, &bv );
+			break;
+
+		case LDAP_BACK_CFG_NOREFS:
+			c->value_int = META_BACK_CMN_NOREFS(mc);
+			break;
+
+		case LDAP_BACK_CFG_NOUNDEFFILTER:
+			c->value_int = META_BACK_CMN_NOUNDEFFILTER(mc);
+			break;
+
+		case LDAP_BACK_CFG_NRETRIES:
+			if ( mc->mc_nretries == META_RETRY_FOREVER ) {
+				BER_BVSTR( &bv, "forever" );
+			} else if ( mc->mc_nretries == META_RETRY_NEVER ) {
+				BER_BVSTR( &bv, "never" );
+			} else {
+				bv.bv_len = snprintf( c->cr_msg, sizeof(c->cr_msg), "%d",
+					mc->mc_nretries );
+				bv.bv_val = c->cr_msg;
+			}
+			value_add_one( &c->rvalue_vals, &bv );
+			break;
+
+		case LDAP_BACK_CFG_QUARANTINE:
+			if ( !META_BACK_CMN_QUARANTINE( mc )) {
+				rc = 1;
+				break;
+			}
+			rc = mi->mi_ldap_extra->retry_info_unparse( &mc->mc_quarantine, &bv );
+			if ( rc == 0 ) {
+				ber_bvarray_add( &c->rvalue_vals, &bv );
+			}
+			break;
+
+		case LDAP_BACK_CFG_REBIND:
+			c->value_int = META_BACK_CMN_SAVECRED(mc);
+			break;
+
+		case LDAP_BACK_CFG_TIMEOUT:
+			for ( i = 0; i < SLAP_OP_LAST; i++ ) {
+				if ( mc->mc_timeout[ i ] != META_BACK_CFG_DEFAULT_OPS_TIMEOUT ) {
+					break;
+				}
+			}
+
+			if ( i == SLAP_OP_LAST ) {
+				return 1;
+			}
+
+			BER_BVZERO( &bv );
+			slap_cf_aux_table_unparse( mc->mc_timeout, &bv, timeout_table );
+
+			if ( BER_BVISNULL( &bv ) ) {
+				return 1;
+			}
+
+			for ( i = 0; isspace( (unsigned char) bv.bv_val[ i ] ); i++ )
+				/* count spaces */ ;
+
+			if ( i ) {
+				bv.bv_len -= i;
+				AC_MEMCPY( bv.bv_val, &bv.bv_val[ i ],
+					bv.bv_len + 1 );
+			}
+
+			ber_bvarray_add( &c->rvalue_vals, &bv );
+			break;
+
+		case LDAP_BACK_CFG_VERSION:
+			if ( mc->mc_version == 0 )
+				return 1;
+			c->value_int = mc->mc_version;
+			break;
+
+#ifdef SLAP_CONTROL_X_SESSION_TRACKING
+		case LDAP_BACK_CFG_ST_REQUEST:
+			c->value_int = META_BACK_CMN_ST_REQUEST( mc );
+			break;
+#endif /* SLAP_CONTROL_X_SESSION_TRACKING */
+
+		case LDAP_BACK_CFG_T_F:
+			enum_to_verb( t_f_mode, (mc->mc_flags & LDAP_BACK_F_T_F_MASK2), &bv );
+			if ( BER_BVISNULL( &bv ) ) {
+				/* there's something wrong... */
+				assert( 0 );
+				rc = 1;
+
+			} else {
+				value_add_one( &c->rvalue_vals, &bv );
+			}
+			break;
+
+		case LDAP_BACK_CFG_TLS: {
+			struct berval bc = BER_BVNULL, bv2;
+
+			if (( mc->mc_flags & LDAP_BACK_F_TLS_MASK ) == LDAP_BACK_F_NONE ) {
+				rc = 1;
+				break;
+			}
+			enum_to_verb( tls_mode, ( mc->mc_flags & LDAP_BACK_F_TLS_MASK ), &bv );
+			assert( !BER_BVISNULL( &bv ) );
+
+			if ( mt ) {
+				bindconf_tls_unparse( &mt->mt_tls, &bc );
+			}
+
+			if ( !BER_BVISEMPTY( &bc )) {
+				bv2.bv_len = bv.bv_len + bc.bv_len + 1;
+				bv2.bv_val = ch_malloc( bv2.bv_len + 1 );
+				strcpy( bv2.bv_val, bv.bv_val );
+				bv2.bv_val[bv.bv_len] = ' ';
+				strcpy( &bv2.bv_val[bv.bv_len + 1], bc.bv_val );
+				ber_memfree( bc.bv_val );
+				ber_bvarray_add( &c->rvalue_vals, &bv2 );
+			} else {
+				value_add_one( &c->rvalue_vals, &bv );
+			}
+			} break;
+
+		/* target attrs */
+		case LDAP_BACK_CFG_URI: {
+			char *p2, *p1 = strchr( mt->mt_uri, ' ' );
+			bv.bv_len = strlen( mt->mt_uri ) + 3 + mt->mt_psuffix.bv_len;
+			bv.bv_val = ch_malloc( bv.bv_len + 1 );
+			p2 = bv.bv_val;
+			*p2++ = '"';
+			if ( p1 ) {
+				p2 = lutil_strncopy( p2, mt->mt_uri, p1 - mt->mt_uri );
+			} else {
+				p2 = lutil_strcopy( p2, mt->mt_uri );
+			}
+			*p2++ = '/';
+			p2 = lutil_strcopy( p2, mt->mt_psuffix.bv_val );
+			*p2++ = '"';
+			if ( p1 ) {
+				strcpy( p2, p1 );
+			}
+			ber_bvarray_add( &c->rvalue_vals, &bv );
+			} break;
+
+		case LDAP_BACK_CFG_IDASSERT_AUTHZFROM: {
+			BerVarray	*bvp;
+			int		i;
+			struct berval	bv = BER_BVNULL;
+			char		buf[SLAP_TEXT_BUFLEN];
+
+			bvp = &mt->mt_idassert_authz;
+			if ( *bvp == NULL ) {
+				if ( mt->mt_idassert_flags & LDAP_BACK_AUTH_AUTHZ_ALL )
+				{
+					BER_BVSTR( &bv, "*" );
+					value_add_one( &c->rvalue_vals, &bv );
+
+				} else {
+					rc = 1;
+				}
+				break;
+			}
+
+			for ( i = 0; !BER_BVISNULL( &((*bvp)[ i ]) ); i++ ) {
+				char *ptr;
+				int len = snprintf( buf, sizeof( buf ), SLAP_X_ORDERED_FMT, i );
+				bv.bv_len = ((*bvp)[ i ]).bv_len + len;
+				bv.bv_val = ber_memrealloc( bv.bv_val, bv.bv_len + 1 );
+				ptr = bv.bv_val;
+				ptr = lutil_strcopy( ptr, buf );
+				ptr = lutil_strncopy( ptr, ((*bvp)[ i ]).bv_val, ((*bvp)[ i ]).bv_len );
+				value_add_one( &c->rvalue_vals, &bv );
+			}
+			if ( bv.bv_val ) {
+				ber_memfree( bv.bv_val );
+			}
+			break;
+		}
+
+		case LDAP_BACK_CFG_IDASSERT_BIND: {
+			int		i;
+			struct berval	bc = BER_BVNULL;
+			char		*ptr;
+
+			if ( mt->mt_idassert_authmethod == LDAP_AUTH_NONE ) {
+				return 1;
+			} else {
+				ber_len_t	len;
+
+				switch ( mt->mt_idassert_mode ) {
+				case LDAP_BACK_IDASSERT_OTHERID:
+				case LDAP_BACK_IDASSERT_OTHERDN:
+					break;
+
+				default: {
+					struct berval	mode = BER_BVNULL;
+
+					enum_to_verb( idassert_mode, mt->mt_idassert_mode, &mode );
+					if ( BER_BVISNULL( &mode ) ) {
+						/* there's something wrong... */
+						assert( 0 );
+						rc = 1;
+
+					} else {
+						bv.bv_len = STRLENOF( "mode=" ) + mode.bv_len;
+						bv.bv_val = ch_malloc( bv.bv_len + 1 );
+
+						ptr = lutil_strcopy( bv.bv_val, "mode=" );
+						ptr = lutil_strcopy( ptr, mode.bv_val );
+					}
+					break;
+				}
+				}
+
+				if ( mt->mt_idassert_flags & LDAP_BACK_AUTH_NATIVE_AUTHZ ) {
+					len = bv.bv_len + STRLENOF( "authz=native" );
+
+					if ( !BER_BVISEMPTY( &bv ) ) {
+						len += STRLENOF( " " );
+					}
+
+					bv.bv_val = ch_realloc( bv.bv_val, len + 1 );
+
+					ptr = &bv.bv_val[ bv.bv_len ];
+
+					if ( !BER_BVISEMPTY( &bv ) ) {
+						ptr = lutil_strcopy( ptr, " " );
+					}
+
+					(void)lutil_strcopy( ptr, "authz=native" );
+				}
+
+				len = bv.bv_len + STRLENOF( "flags=non-prescriptive,override,obsolete-encoding-workaround,proxy-authz-non-critical,dn-authzid" );
+				/* flags */
+				if ( !BER_BVISEMPTY( &bv ) ) {
+					len += STRLENOF( " " );
+				}
+
+				bv.bv_val = ch_realloc( bv.bv_val, len + 1 );
+
+				ptr = &bv.bv_val[ bv.bv_len ];
+
+				if ( !BER_BVISEMPTY( &bv ) ) {
+					ptr = lutil_strcopy( ptr, " " );
+				}
+
+				ptr = lutil_strcopy( ptr, "flags=" );
+
+				if ( mt->mt_idassert_flags & LDAP_BACK_AUTH_PRESCRIPTIVE ) {
+					ptr = lutil_strcopy( ptr, "prescriptive" );
+				} else {
+					ptr = lutil_strcopy( ptr, "non-prescriptive" );
+				}
+
+				if ( mt->mt_idassert_flags & LDAP_BACK_AUTH_OVERRIDE ) {
+					ptr = lutil_strcopy( ptr, ",override" );
+				}
+
+				if ( mt->mt_idassert_flags & LDAP_BACK_AUTH_OBSOLETE_PROXY_AUTHZ ) {
+					ptr = lutil_strcopy( ptr, ",obsolete-proxy-authz" );
+
+				} else if ( mt->mt_idassert_flags & LDAP_BACK_AUTH_OBSOLETE_ENCODING_WORKAROUND ) {
+					ptr = lutil_strcopy( ptr, ",obsolete-encoding-workaround" );
+				}
+
+				if ( mt->mt_idassert_flags & LDAP_BACK_AUTH_PROXYAUTHZ_CRITICAL ) {
+					ptr = lutil_strcopy( ptr, ",proxy-authz-critical" );
+
+				} else {
+					ptr = lutil_strcopy( ptr, ",proxy-authz-non-critical" );
+				}
+
+#ifdef SLAP_AUTH_DN
+				switch ( mt->mt_idassert_flags & LDAP_BACK_AUTH_DN_MASK ) {
+				case LDAP_BACK_AUTH_DN_AUTHZID:
+					ptr = lutil_strcopy( ptr, ",dn-authzid" );
+					break;
+
+				case LDAP_BACK_AUTH_DN_WHOAMI:
+					ptr = lutil_strcopy( ptr, ",dn-whoami" );
+					break;
+
+				default:
+#if 0 /* implicit */
+					ptr = lutil_strcopy( ptr, ",dn-none" );
+#endif
+					break;
+				}
+#endif
+
+				bv.bv_len = ( ptr - bv.bv_val );
+				/* end-of-flags */
+			}
+
+			bindconf_unparse( &mt->mt_idassert.si_bc, &bc );
+
+			if ( !BER_BVISNULL( &bv ) ) {
+				ber_len_t	len = bv.bv_len + bc.bv_len;
+
+				bv.bv_val = ch_realloc( bv.bv_val, len + 1 );
+
+				assert( bc.bv_val[ 0 ] == ' ' );
+
+				ptr = lutil_strcopy( &bv.bv_val[ bv.bv_len ], bc.bv_val );
+				free( bc.bv_val );
+				bv.bv_len = ptr - bv.bv_val;
+
+			} else {
+				for ( i = 0; isspace( (unsigned char) bc.bv_val[ i ] ); i++ )
+					/* count spaces */ ;
+
+				if ( i ) {
+					bc.bv_len -= i;
+					AC_MEMCPY( bc.bv_val, &bc.bv_val[ i ], bc.bv_len + 1 );
+				}
+
+				bv = bc;
+			}
+
+			ber_bvarray_add( &c->rvalue_vals, &bv );
+
+			break;
+		}
+
+		case LDAP_BACK_CFG_SUFFIXM:
+			if ( mt->mt_lsuffixm.bv_val ) {
+				struct berval bv;
+				char *ptr;
+				bv.bv_len = mt->mt_lsuffixm.bv_len + 2 + 1 + mt->mt_rsuffixm.bv_len + 2;
+				bv.bv_val = ch_malloc( bv.bv_len + 1 );
+				ptr = bv.bv_val;
+				*ptr++ = '"';
+				ptr = lutil_strcopy(ptr, mt->mt_lsuffixm.bv_val);
+				ptr = lutil_strcopy(ptr, "\" \"");
+				ptr = lutil_strcopy(ptr, mt->mt_rsuffixm.bv_val);
+				*ptr++ = '"';
+				*ptr = '\0';
+				ber_bvarray_add( &c->rvalue_vals, &bv );
+				rc = 0;
+			} else
+				rc = 1;
+			break;
+
+		case LDAP_BACK_CFG_SUBTREE_EX:
+		case LDAP_BACK_CFG_SUBTREE_IN:
+			rc = asyncmeta_subtree_unparse( c, mt );
+			break;
+
+		case LDAP_BACK_CFG_FILTER:
+			if ( mt->mt_filter == NULL ) {
+				rc = 1;
+			} else {
+				metafilter_t *mf;
+				for ( mf = mt->mt_filter; mf; mf = mf->mf_next )
+					value_add_one( &c->rvalue_vals, &mf->mf_regex_pattern );
+			}
+			break;
+		case LDAP_BACK_CFG_MAX_PENDING_OPS:
+			c->value_int = mi->mi_max_pending_ops;
+			break;
+
+		case LDAP_BACK_CFG_MAX_TARGET_CONNS:
+			c->value_int = mi->mi_max_target_conns;
+			break;
+		case LDAP_BACK_CFG_MAX_TIMEOUT_OPS:
+			c->value_int = mi->mi_max_timeout_ops;
+			break;
+
+		case LDAP_BACK_CFG_KEEPALIVE: {
+				struct berval bv;
+				char buf[AC_LINE_MAX];
+				bv.bv_len = AC_LINE_MAX;
+				bv.bv_val = &buf[0];
+				slap_keepalive_parse(&bv, &mt->mt_tls.sb_keepalive, 0, 0, 1);
+				value_add_one( &c->rvalue_vals, &bv );
+				break;
+			}
+
+		case LDAP_BACK_CFG_TCP_USER_TIMEOUT:
+			c->value_uint = mt->mt_tls.sb_tcp_user_timeout;
+			break;
+
+		default:
+			rc = 1;
+		}
+		return rc;
+	} else if ( c->op == LDAP_MOD_DELETE ) {
+		switch( c->type ) {
+		/* Base attrs */
+		case LDAP_BACK_CFG_DNCACHE_TTL:
+			mi->mi_cache.ttl = META_DNCACHE_DISABLED;
+			break;
+
+		case LDAP_BACK_CFG_IDLE_TIMEOUT:
+			mi->mi_idle_timeout = 0;
+			break;
+
+		case LDAP_BACK_CFG_ONERR:
+			mi->mi_flags &= ~META_BACK_F_ONERR_MASK;
+			break;
+
+		case LDAP_BACK_CFG_PSEUDOROOT_BIND_DEFER:
+			mi->mi_flags &= ~META_BACK_F_DEFER_ROOTDN_BIND;
+			break;
+
+		case LDAP_BACK_CFG_CONNPOOLMAX:
+			mi->mi_conn_priv_max = LDAP_BACK_CONN_PRIV_MIN;
+			break;
+
+		/* common attrs */
+		case LDAP_BACK_CFG_BIND_TIMEOUT:
+			mc->mc_bind_timeout.tv_sec = 0;
+			mc->mc_bind_timeout.tv_usec = 0;
+			break;
+
+		case LDAP_BACK_CFG_CANCEL:
+			mc->mc_flags &= ~LDAP_BACK_F_CANCEL_MASK2;
+			break;
+
+		case LDAP_BACK_CFG_CHASE:
+			mc->mc_flags &= ~LDAP_BACK_F_CHASE_REFERRALS;
+			break;
+
+#ifdef SLAPD_META_CLIENT_PR
+		case LDAP_BACK_CFG_CLIENT_PR:
+			mc->mc_ps = META_CLIENT_PR_DISABLE;
+			break;
+#endif /* SLAPD_META_CLIENT_PR */
+
+		case LDAP_BACK_CFG_DEFAULT_T:
+			mi->mi_defaulttarget = META_DEFAULT_TARGET_NONE;
+			break;
+
+		case LDAP_BACK_CFG_NETWORK_TIMEOUT:
+			mc->mc_network_timeout = 0;
+			break;
+
+		case LDAP_BACK_CFG_NOREFS:
+			mc->mc_flags &= ~LDAP_BACK_F_NOREFS;
+			break;
+
+		case LDAP_BACK_CFG_NOUNDEFFILTER:
+			mc->mc_flags &= ~LDAP_BACK_F_NOUNDEFFILTER;
+			break;
+
+		case LDAP_BACK_CFG_NRETRIES:
+			mc->mc_nretries = META_RETRY_DEFAULT;
+			break;
+
+		case LDAP_BACK_CFG_QUARANTINE:
+			if ( META_BACK_CMN_QUARANTINE( mc )) {
+				mi->mi_ldap_extra->retry_info_destroy( &mc->mc_quarantine );
+				mc->mc_flags &= ~LDAP_BACK_F_QUARANTINE;
+				if ( mc == &mt->mt_mc ) {
+					ldap_pvt_thread_mutex_destroy( &mt->mt_quarantine_mutex );
+					mt->mt_isquarantined = 0;
+				}
+			}
+			break;
+
+		case LDAP_BACK_CFG_REBIND:
+			mc->mc_flags &= ~LDAP_BACK_F_SAVECRED;
+			break;
+
+		case LDAP_BACK_CFG_TIMEOUT:
+			for ( i = 0; i < SLAP_OP_LAST; i++ ) {
+				mc->mc_timeout[ i ] = 0;
+			}
+			break;
+
+		case LDAP_BACK_CFG_VERSION:
+			mc->mc_version = 0;
+			break;
+
+#ifdef SLAP_CONTROL_X_SESSION_TRACKING
+		case LDAP_BACK_CFG_ST_REQUEST:
+			mc->mc_flags &= ~LDAP_BACK_F_ST_REQUEST;
+			break;
+#endif /* SLAP_CONTROL_X_SESSION_TRACKING */
+
+		case LDAP_BACK_CFG_T_F:
+			mc->mc_flags &= ~LDAP_BACK_F_T_F_MASK2;
+			break;
+
+		case LDAP_BACK_CFG_TLS:
+			mc->mc_flags &= ~LDAP_BACK_F_TLS_MASK;
+			if ( mt )
+				bindconf_free( &mt->mt_tls );
+			break;
+
+		/* target attrs */
+		case LDAP_BACK_CFG_URI:
+			if ( mt->mt_uri ) {
+				ch_free( mt->mt_uri );
+				mt->mt_uri = NULL;
+			}
+			/* FIXME: should have a way to close all cached
+			 * connections associated with this target.
+			 */
+			break;
+
+		case LDAP_BACK_CFG_IDASSERT_AUTHZFROM: {
+			BerVarray *bvp;
+
+			bvp = &mt->mt_idassert_authz;
+			if ( c->valx < 0 ) {
+				if ( *bvp != NULL ) {
+					ber_bvarray_free( *bvp );
+					*bvp = NULL;
+				}
+
+			} else {
+				if ( *bvp == NULL ) {
+					rc = 1;
+					break;
+				}
+
+				for ( i = 0; !BER_BVISNULL( &((*bvp)[ i ]) ); i++ )
+					;
+
+				if ( i >= c->valx ) {
+					rc = 1;
+					break;
+				}
+				ber_memfree( ((*bvp)[ c->valx ]).bv_val );
+				for ( i = c->valx; !BER_BVISNULL( &((*bvp)[ i + 1 ]) ); i++ ) {
+					(*bvp)[ i ] = (*bvp)[ i + 1 ];
+				}
+				BER_BVZERO( &((*bvp)[ i ]) );
+			}
+			} break;
+
+		case LDAP_BACK_CFG_IDASSERT_BIND:
+			bindconf_free( &mt->mt_idassert.si_bc );
+			memset( &mt->mt_idassert, 0, sizeof( slap_idassert_t ) );
+			break;
+
+		case LDAP_BACK_CFG_SUFFIXM:
+			if ( mt->mt_lsuffixm.bv_val ) {
+				ch_free( mt->mt_lsuffixm.bv_val );
+				ch_free( mt->mt_rsuffixm.bv_val );
+				BER_BVZERO( &mt->mt_lsuffixm );
+				BER_BVZERO( &mt->mt_rsuffixm );
+			}
+			break;
+
+		case LDAP_BACK_CFG_SUBTREE_EX:
+		case LDAP_BACK_CFG_SUBTREE_IN:
+			/* can only be one of exclude or include */
+			if (( c->type == LDAP_BACK_CFG_SUBTREE_EX ) ^ mt->mt_subtree_exclude ) {
+				rc = 1;
+				break;
+			}
+			if ( c->valx < 0 ) {
+				asyncmeta_subtree_destroy( mt->mt_subtree );
+				mt->mt_subtree = NULL;
+			} else {
+				a_metasubtree_t *ms, **mprev;
+				for (i=0, mprev = &mt->mt_subtree, ms = *mprev; ms; ms = *mprev) {
+					if ( i == c->valx ) {
+						*mprev = ms->ms_next;
+						asyncmeta_subtree_free( ms );
+						break;
+					}
+					i++;
+					mprev = &ms->ms_next;
+				}
+				if ( i != c->valx )
+					rc = 1;
+			}
+			break;
+
+		case LDAP_BACK_CFG_FILTER:
+			if ( c->valx < 0 ) {
+				asyncmeta_filter_destroy( mt->mt_filter );
+				mt->mt_filter = NULL;
+			} else {
+				metafilter_t *mf, **mprev;
+				for (i=0, mprev = &mt->mt_filter, mf = *mprev; mf; mf = *mprev) {
+					if ( i == c->valx ) {
+						*mprev = mf->mf_next;
+						asyncmeta_filter_free( mf );
+						break;
+					}
+					i++;
+					mprev = &mf->mf_next;
+				}
+				if ( i != c->valx )
+					rc = 1;
+			}
+			break;
+		case LDAP_BACK_CFG_MAX_PENDING_OPS:
+			mi->mi_max_pending_ops = 0;
+			break;
+
+		case LDAP_BACK_CFG_MAX_TARGET_CONNS:
+			mi->mi_max_target_conns = 0;
+			break;
+
+		case LDAP_BACK_CFG_MAX_TIMEOUT_OPS:
+			mi->mi_max_timeout_ops = 0;
+			break;
+
+		case LDAP_BACK_CFG_KEEPALIVE:
+			mt->mt_tls.sb_keepalive.sk_idle = 0;
+			mt->mt_tls.sb_keepalive.sk_probes = 0;
+			mt->mt_tls.sb_keepalive.sk_interval = 0;
+			break;
+
+		case LDAP_BACK_CFG_TCP_USER_TIMEOUT:
+			mt->mt_tls.sb_tcp_user_timeout = 0;
+			break;
+
+		default:
+			rc = 1;
+			break;
+		}
+
+		return rc;
+	}
+
+	if ( c->op == SLAP_CONFIG_ADD ) {
+		if ( c->type >= LDAP_BACK_CFG_LAST_BASE ) {
+			/* exclude CFG_URI from this check */
+			if ( c->type > LDAP_BACK_CFG_LAST_BOTH ) {
+				if ( !mi->mi_ntargets ) {
+					snprintf( c->cr_msg, sizeof( c->cr_msg ),
+						"need \"uri\" directive first" );
+					Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+					return 1;
+				}
+			}
+			if ( mi->mi_ntargets ) {
+				mt = mi->mi_targets[ mi->mi_ntargets-1 ];
+				mc = &mt->mt_mc;
+			} else {
+				mt = NULL;
+				mc = &mi->mi_mc;
+			}
+		}
+	} else {
+		if ( c->table == Cft_Database ) {
+			mt = NULL;
+			mc = &mi->mi_mc;
+		} else {
+			mt = c->ca_private;
+			if ( mt )
+				mc = &mt->mt_mc;
+			else
+				mc = NULL;
+		}
+	}
+
+	switch( c->type ) {
+	case LDAP_BACK_CFG_URI: {
+		LDAPURLDesc 	*ludp;
+		struct berval	dn;
+		int		j;
+
+		char		**uris = NULL;
+
+		if ( c->be->be_nsuffix == NULL ) {
+			snprintf( c->cr_msg, sizeof( c->cr_msg ),
+				"the suffix must be defined before any target" );
+			Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+			return 1;
+		}
+
+		i = mi->mi_ntargets++;
+
+		mi->mi_targets = ( a_metatarget_t ** )ch_realloc( mi->mi_targets,
+			sizeof( a_metatarget_t * ) * mi->mi_ntargets );
+		if ( mi->mi_targets == NULL ) {
+			snprintf( c->cr_msg, sizeof( c->cr_msg ),
+				"out of memory while storing server name"
+				" in \"%s <protocol>://<server>[:port]/<naming context>\"",
+				c->argv[0] );
+			Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+			return 1;
+		}
+
+		if ( asyncmeta_back_new_target( &mi->mi_targets[ i ] ) != 0 ) {
+			snprintf( c->cr_msg, sizeof( c->cr_msg ),
+				"unable to init server"
+				" in \"%s <protocol>://<server>[:port]/<naming context>\"",
+				c->argv[0] );
+			Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+			return 1;
+		}
+
+		mt = mi->mi_targets[ i ];
+
+		mt->mt_rebind_f = mi->mi_rebind_f;
+		mt->mt_urllist_f = mi->mi_urllist_f;
+		mt->mt_urllist_p = mt;
+
+		if ( META_BACK_QUARANTINE( mi ) ) {
+			ldap_pvt_thread_mutex_init( &mt->mt_quarantine_mutex );
+		}
+		mt->mt_mc = mi->mi_mc;
+
+		for ( j = 1; j < c->argc; j++ ) {
+			char	**tmpuris = ldap_str2charray( c->argv[ j ], "\t" );
+
+			if ( tmpuris == NULL ) {
+				snprintf( c->cr_msg, sizeof( c->cr_msg ),
+					"unable to parse URIs #%d"
+					" in \"%s <protocol>://<server>[:port]/<naming context>\"",
+					j-1, c->argv[0] );
+				Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+				return 1;
+			}
+
+			if ( j == 1 ) {
+				uris = tmpuris;
+
+			} else {
+				ldap_charray_merge( &uris, tmpuris );
+				ldap_charray_free( tmpuris );
+			}
+		}
+
+		for ( j = 0; uris[ j ] != NULL; j++ ) {
+			char *tmpuri = NULL;
+
+			/*
+			 * uri MUST be legal!
+			 */
+			if ( ldap_url_parselist_ext( &ludp, uris[ j ], "\t",
+					LDAP_PVT_URL_PARSE_NONE ) != LDAP_SUCCESS
+				|| ludp->lud_next != NULL )
+			{
+				snprintf( c->cr_msg, sizeof( c->cr_msg ),
+					"unable to parse URI #%d"
+					" in \"%s <protocol>://<server>[:port]/<naming context>\"",
+					j-1, c->argv[0] );
+				Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+				ldap_charray_free( uris );
+				return 1;
+			}
+
+			if ( j == 0 ) {
+
+				/*
+				 * uri MUST have the <dn> part!
+				 */
+				if ( ludp->lud_dn == NULL ) {
+					snprintf( c->cr_msg, sizeof( c->cr_msg ),
+						"missing <naming context> "
+						" in \"%s <protocol>://<server>[:port]/<naming context>\"",
+						c->argv[0] );
+					Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+					ldap_free_urllist( ludp );
+					ldap_charray_free( uris );
+					return 1;
+				}
+
+				/*
+				 * copies and stores uri and suffix
+				 */
+				ber_str2bv( ludp->lud_dn, 0, 0, &dn );
+				rc = dnPrettyNormal( NULL, &dn, &mt->mt_psuffix,
+					&mt->mt_nsuffix, NULL );
+				if ( rc != LDAP_SUCCESS ) {
+					snprintf( c->cr_msg, sizeof( c->cr_msg ),
+						"target DN is invalid \"%s\"",
+						c->argv[1] );
+					Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+					ldap_free_urllist( ludp );
+					ldap_charray_free( uris );
+					return( 1 );
+				}
+
+				ludp->lud_dn[ 0 ] = '\0';
+
+				switch ( ludp->lud_scope ) {
+				case LDAP_SCOPE_DEFAULT:
+					mt->mt_scope = LDAP_SCOPE_SUBTREE;
+					break;
+
+				case LDAP_SCOPE_SUBTREE:
+				case LDAP_SCOPE_SUBORDINATE:
+					mt->mt_scope = ludp->lud_scope;
+					break;
+
+				default:
+					snprintf( c->cr_msg, sizeof( c->cr_msg ),
+						"invalid scope for target \"%s\"",
+						c->argv[1] );
+					Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+					ldap_free_urllist( ludp );
+					ldap_charray_free( uris );
+					return( 1 );
+				}
+
+			} else {
+				/* check all, to apply the scope check on the first one */
+				if ( ludp->lud_dn != NULL && ludp->lud_dn[ 0 ] != '\0' ) {
+					snprintf( c->cr_msg, sizeof( c->cr_msg ),
+						"multiple URIs must have no DN part" );
+					Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+					ldap_free_urllist( ludp );
+					ldap_charray_free( uris );
+					return( 1 );
+
+				}
+			}
+
+			tmpuri = ldap_url_list2urls( ludp );
+			ldap_free_urllist( ludp );
+			if ( tmpuri == NULL ) {
+				snprintf( c->cr_msg, sizeof( c->cr_msg ), "no memory?" );
+				Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+				ldap_charray_free( uris );
+				return( 1 );
+			}
+			ldap_memfree( uris[ j ] );
+			uris[ j ] = tmpuri;
+		}
+
+		mt->mt_uri = ldap_charray2str( uris, " " );
+		ldap_charray_free( uris );
+		if ( mt->mt_uri == NULL) {
+			snprintf( c->cr_msg, sizeof( c->cr_msg ), "no memory?" );
+			Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+			return( 1 );
+		}
+
+		/*
+		 * uri MUST be a branch of suffix!
+		 */
+		for ( j = 0; !BER_BVISNULL( &c->be->be_nsuffix[ j ] ); j++ ) {
+			if ( dnIsSuffix( &mt->mt_nsuffix, &c->be->be_nsuffix[ j ] ) ) {
+				break;
+			}
+		}
+
+		if ( BER_BVISNULL( &c->be->be_nsuffix[ j ] ) ) {
+			snprintf( c->cr_msg, sizeof( c->cr_msg ),
+				"<naming context> of URI must be within the naming context of this database." );
+			Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+			return 1;
+		}
+		c->ca_private = mt;
+		config_push_cleanup( c, asyncmeta_cf_cleanup );
+	} break;
+	case LDAP_BACK_CFG_SUBTREE_EX:
+	case LDAP_BACK_CFG_SUBTREE_IN:
+	/* subtree-exclude */
+		if ( asyncmeta_subtree_config( mt, c )) {
+			Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+			return 1;
+		}
+		break;
+
+	case LDAP_BACK_CFG_FILTER: {
+		metafilter_t *mf, **m2;
+		mf = ch_malloc( sizeof( metafilter_t ));
+		rc = regcomp( &mf->mf_regex, c->argv[1], REG_EXTENDED );
+		if ( rc ) {
+			char regerr[ SLAP_TEXT_BUFLEN ];
+			regerror( rc, &mf->mf_regex, regerr, sizeof(regerr) );
+			snprintf( c->cr_msg, sizeof( c->cr_msg ),
+				"regular expression \"%s\" bad because of %s",
+				c->argv[1], regerr );
+			ch_free( mf );
+			return 1;
+		}
+		ber_str2bv( c->argv[1], 0, 1, &mf->mf_regex_pattern );
+		for ( m2 = &mt->mt_filter; *m2; m2 = &(*m2)->mf_next )
+			;
+		*m2 = mf;
+	} break;
+	case LDAP_BACK_CFG_MAX_PENDING_OPS:
+		if (c->value_int < 0) {
+			snprintf( c->cr_msg, sizeof( c->cr_msg ),
+				  "max-pending-ops invalid value %d",
+				  c->value_int);
+			return 1;
+		}
+		mi->mi_max_pending_ops = c->value_int;
+		break;
+	case LDAP_BACK_CFG_MAX_TARGET_CONNS:
+	{
+		if (c->value_int < 0) {
+			snprintf( c->cr_msg, sizeof( c->cr_msg ),
+				  "max-target-conns invalid value %d",
+				  c->value_int);
+			return 1;
+		}
+		mi->mi_max_target_conns = c->value_int;
+	}
+		break;
+	case LDAP_BACK_CFG_MAX_TIMEOUT_OPS:
+		if (c->value_int < 0) {
+			snprintf( c->cr_msg, sizeof( c->cr_msg ),
+				  "max-timeout-ops invalid value %d",
+				  c->value_int);
+			return 1;
+		}
+		mi->mi_max_timeout_ops = c->value_int;
+		break;
+
+	case LDAP_BACK_CFG_DEFAULT_T:
+	/* default target directive */
+		i = mi->mi_ntargets - 1;
+
+		if ( c->argc == 1 ) {
+			if ( i < 0 ) {
+				snprintf( c->cr_msg, sizeof( c->cr_msg ),
+					"\"%s\" alone must be inside a \"uri\" directive",
+					c->argv[0] );
+				Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+				return 1;
+			}
+			mi->mi_defaulttarget = i;
+
+		} else {
+			if ( strcasecmp( c->argv[ 1 ], "none" ) == 0 ) {
+				if ( i >= 0 ) {
+					snprintf( c->cr_msg, sizeof( c->cr_msg ),
+						"\"%s none\" should go before uri definitions",
+						c->argv[0] );
+					Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+				}
+				mi->mi_defaulttarget = META_DEFAULT_TARGET_NONE;
+
+			} else {
+
+				if ( lutil_atoi( &mi->mi_defaulttarget, c->argv[ 1 ] ) != 0
+					|| mi->mi_defaulttarget < 0
+					|| mi->mi_defaulttarget >= i - 1 )
+				{
+					snprintf( c->cr_msg, sizeof( c->cr_msg ),
+						"illegal target number %d",
+						mi->mi_defaulttarget );
+					Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+					return 1;
+				}
+			}
+		}
+		break;
+
+	case LDAP_BACK_CFG_DNCACHE_TTL:
+	/* ttl of dn cache */
+		if ( strcasecmp( c->argv[ 1 ], "forever" ) == 0 ) {
+			mi->mi_cache.ttl = META_DNCACHE_FOREVER;
+
+		} else if ( strcasecmp( c->argv[ 1 ], "disabled" ) == 0 ) {
+			mi->mi_cache.ttl = META_DNCACHE_DISABLED;
+
+		} else {
+			unsigned long	t;
+
+			if ( lutil_parse_time( c->argv[ 1 ], &t ) != 0 ) {
+				snprintf( c->cr_msg, sizeof( c->cr_msg ),
+					"unable to parse dncache ttl \"%s\"",
+					c->argv[ 1 ] );
+				Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+				return 1;
+			}
+			mi->mi_cache.ttl = (time_t)t;
+		}
+		break;
+
+	case LDAP_BACK_CFG_NETWORK_TIMEOUT: {
+	/* network timeout when connecting to ldap servers */
+		unsigned long t;
+
+		if ( lutil_parse_time( c->argv[ 1 ], &t ) ) {
+			snprintf( c->cr_msg, sizeof( c->cr_msg ),
+				"unable to parse network timeout \"%s\"",
+				c->argv[ 1 ] );
+			Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+			return 1;
+		}
+		mc->mc_network_timeout = (time_t)t;
+		} break;
+
+	case LDAP_BACK_CFG_IDLE_TIMEOUT: {
+	/* idle timeout when connecting to ldap servers */
+		unsigned long	t;
+
+		if ( lutil_parse_time( c->argv[ 1 ], &t ) ) {
+			snprintf( c->cr_msg, sizeof( c->cr_msg ),
+				"unable to parse idle timeout \"%s\"",
+				c->argv[ 1 ] );
+			Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+			return 1;
+
+		}
+		mi->mi_idle_timeout = (time_t)t;
+		} break;
+
+	case LDAP_BACK_CFG_BIND_TIMEOUT:
+	/* bind timeout when connecting to ldap servers */
+		mc->mc_bind_timeout.tv_sec = c->value_ulong/1000000;
+		mc->mc_bind_timeout.tv_usec = c->value_ulong%1000000;
+		break;
+
+	case LDAP_BACK_CFG_REBIND:
+	/* save bind creds for referral rebinds? */
+		if ( c->argc == 1 || c->value_int ) {
+			mc->mc_flags |= LDAP_BACK_F_SAVECRED;
+		} else {
+			mc->mc_flags &= ~LDAP_BACK_F_SAVECRED;
+		}
+		break;
+
+	case LDAP_BACK_CFG_CHASE:
+		if ( c->argc == 1 || c->value_int ) {
+			mc->mc_flags |= LDAP_BACK_F_CHASE_REFERRALS;
+		} else {
+			mc->mc_flags &= ~LDAP_BACK_F_CHASE_REFERRALS;
+		}
+		break;
+
+	case LDAP_BACK_CFG_TLS:
+		i = verb_to_mask( c->argv[1], tls_mode );
+		if ( BER_BVISNULL( &tls_mode[i].word ) ) {
+			snprintf( c->cr_msg, sizeof( c->cr_msg ),
+				"%s unknown argument \"%s\"",
+				c->argv[0], c->argv[1] );
+			Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+			return 1;
+		}
+		mc->mc_flags &= ~LDAP_BACK_F_TLS_MASK;
+		mc->mc_flags |= tls_mode[i].mask;
+
+		if ( c->argc > 2 ) {
+			if ( c->op == SLAP_CONFIG_ADD && mi->mi_ntargets == 0 ) {
+				snprintf( c->cr_msg, sizeof( c->cr_msg ),
+					"need \"uri\" directive first" );
+				Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+				return 1;
+			}
+
+			for ( i = 2; i < c->argc; i++ ) {
+				if ( bindconf_tls_parse( c->argv[i], &mt->mt_tls ))
+					return 1;
+			}
+			bindconf_tls_defaults( &mt->mt_tls );
+		}
+		break;
+
+	case LDAP_BACK_CFG_T_F:
+		i = verb_to_mask( c->argv[1], t_f_mode );
+		if ( BER_BVISNULL( &t_f_mode[i].word ) ) {
+			snprintf( c->cr_msg, sizeof( c->cr_msg ),
+				"%s unknown argument \"%s\"",
+				c->argv[0], c->argv[1] );
+			Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+			return 1;
+		}
+		mc->mc_flags &= ~LDAP_BACK_F_T_F_MASK2;
+		mc->mc_flags |= t_f_mode[i].mask;
+		break;
+
+	case LDAP_BACK_CFG_ONERR:
+	/* onerr? */
+		i = verb_to_mask( c->argv[1], onerr_mode );
+		if ( BER_BVISNULL( &onerr_mode[i].word ) ) {
+			snprintf( c->cr_msg, sizeof( c->cr_msg ),
+				"%s unknown argument \"%s\"",
+				c->argv[0], c->argv[1] );
+			Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+			return 1;
+		}
+		mi->mi_flags &= ~META_BACK_F_ONERR_MASK;
+		mi->mi_flags |= onerr_mode[i].mask;
+		break;
+
+	case LDAP_BACK_CFG_PSEUDOROOT_BIND_DEFER:
+	/* bind-defer? */
+		if ( c->argc == 1 || c->value_int ) {
+			mi->mi_flags |= META_BACK_F_DEFER_ROOTDN_BIND;
+		} else {
+			mi->mi_flags &= ~META_BACK_F_DEFER_ROOTDN_BIND;
+		}
+		break;
+
+	case LDAP_BACK_CFG_CONNPOOLMAX:
+	/* privileged connections pool max size ? */
+		if ( mi->mi_ntargets > 0 ) {
+			snprintf( c->cr_msg, sizeof( c->cr_msg ),
+				"\"%s\" must appear before target definitions",
+				c->argv[0] );
+			Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+			return( 1 );
+		}
+
+		if ( c->value_int < LDAP_BACK_CONN_PRIV_MIN
+			|| c->value_int > LDAP_BACK_CONN_PRIV_MAX )
+		{
+			snprintf( c->cr_msg, sizeof( c->cr_msg ),
+				"invalid max size " "of privileged "
+				"connections pool \"%s\" "
+				"in \"conn-pool-max <n> "
+				"(must be between %d and %d)\"",
+				c->argv[ 1 ],
+				LDAP_BACK_CONN_PRIV_MIN,
+				LDAP_BACK_CONN_PRIV_MAX );
+			Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+			return 1;
+		}
+		mi->mi_conn_priv_max = c->value_int;
+		break;
+
+	case LDAP_BACK_CFG_CANCEL:
+		i = verb_to_mask( c->argv[1], cancel_mode );
+		if ( BER_BVISNULL( &cancel_mode[i].word ) ) {
+			snprintf( c->cr_msg, sizeof( c->cr_msg ),
+				"%s unknown argument \"%s\"",
+				c->argv[0], c->argv[1] );
+			Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+			return 1;
+		}
+		mc->mc_flags &= ~LDAP_BACK_F_CANCEL_MASK2;
+		mc->mc_flags |= cancel_mode[i].mask;
+		break;
+
+	case LDAP_BACK_CFG_TIMEOUT:
+		for ( i = 1; i < c->argc; i++ ) {
+			if ( isdigit( (unsigned char) c->argv[ i ][ 0 ] ) ) {
+				int		j;
+				unsigned	u;
+
+				if ( lutil_atoux( &u, c->argv[ i ], 0 ) != 0 ) {
+					snprintf( c->cr_msg, sizeof( c->cr_msg),
+						"unable to parse timeout \"%s\"",
+						c->argv[ i ] );
+					Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+					return 1;
+				}
+
+				for ( j = 0; j < SLAP_OP_LAST; j++ ) {
+					mc->mc_timeout[ j ] = u;
+				}
+
+				continue;
+			}
+
+			if ( slap_cf_aux_table_parse( c->argv[ i ], mc->mc_timeout, timeout_table, "slapd-meta timeout" ) ) {
+				snprintf( c->cr_msg, sizeof( c->cr_msg),
+					"unable to parse timeout \"%s\"",
+					c->argv[ i ] );
+				Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+				return 1;
+			}
+		}
+		break;
+
+	case LDAP_BACK_CFG_IDASSERT_BIND:
+	/* idassert-bind */
+		rc = mi->mi_ldap_extra->idassert_parse( c, &mt->mt_idassert );
+		break;
+
+	case LDAP_BACK_CFG_IDASSERT_AUTHZFROM:
+	/* idassert-authzFrom */
+		rc = mi->mi_ldap_extra->idassert_authzfrom_parse( c, &mt->mt_idassert );
+		break;
+
+	case LDAP_BACK_CFG_QUARANTINE:
+	/* quarantine */
+		if ( META_BACK_CMN_QUARANTINE( mc ) )
+		{
+			snprintf( c->cr_msg, sizeof( c->cr_msg ),
+				"quarantine already defined" );
+			Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+			return 1;
+		}
+
+		if ( mt ) {
+			mc->mc_quarantine.ri_interval = NULL;
+			mc->mc_quarantine.ri_num = NULL;
+			if ( !META_BACK_QUARANTINE( mi ) ) {
+				ldap_pvt_thread_mutex_init( &mt->mt_quarantine_mutex );
+			}
+		}
+
+		if ( mi->mi_ldap_extra->retry_info_parse( c->argv[ 1 ], &mc->mc_quarantine, c->cr_msg, sizeof( c->cr_msg ) ) ) {
+			Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+			return 1;
+		}
+
+		mc->mc_flags |= LDAP_BACK_F_QUARANTINE;
+		break;
+
+#ifdef SLAP_CONTROL_X_SESSION_TRACKING
+	case LDAP_BACK_CFG_ST_REQUEST:
+	/* session tracking request */
+		if ( c->value_int ) {
+			mc->mc_flags |= LDAP_BACK_F_ST_REQUEST;
+		} else {
+			mc->mc_flags &= ~LDAP_BACK_F_ST_REQUEST;
+		}
+		break;
+#endif /* SLAP_CONTROL_X_SESSION_TRACKING */
+
+	case LDAP_BACK_CFG_SUFFIXM:
+		rc = asyncmeta_suffixm_config( c, c->argc, c->argv, mt );
+		break;
+
+	case LDAP_BACK_CFG_NRETRIES: {
+		int		nretries = META_RETRY_UNDEFINED;
+
+		if ( strcasecmp( c->argv[ 1 ], "forever" ) == 0 ) {
+			nretries = META_RETRY_FOREVER;
+
+		} else if ( strcasecmp( c->argv[ 1 ], "never" ) == 0 ) {
+			nretries = META_RETRY_NEVER;
+
+		} else {
+			if ( lutil_atoi( &nretries, c->argv[ 1 ] ) != 0 ) {
+				snprintf( c->cr_msg, sizeof( c->cr_msg ),
+					"unable to parse nretries {never|forever|<retries>}: \"%s\"",
+					c->argv[ 1 ] );
+				Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+				return 1;
+			}
+		}
+
+		mc->mc_nretries = nretries;
+		} break;
+
+	case LDAP_BACK_CFG_VERSION:
+		if ( c->value_int != 0 && ( c->value_int < LDAP_VERSION_MIN || c->value_int > LDAP_VERSION_MAX ) ) {
+			snprintf( c->cr_msg, sizeof( c->cr_msg ),
+				"unsupported protocol version \"%s\"",
+				c->argv[ 1 ] );
+			Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+			return 1;
+		}
+		mc->mc_version = c->value_int;
+		break;
+
+	case LDAP_BACK_CFG_NOREFS:
+	/* do not return search references */
+		if ( c->value_int ) {
+			mc->mc_flags |= LDAP_BACK_F_NOREFS;
+		} else {
+			mc->mc_flags &= ~LDAP_BACK_F_NOREFS;
+		}
+		break;
+
+	case LDAP_BACK_CFG_NOUNDEFFILTER:
+	/* do not propagate undefined search filters */
+		if ( c->value_int ) {
+			mc->mc_flags |= LDAP_BACK_F_NOUNDEFFILTER;
+		} else {
+			mc->mc_flags &= ~LDAP_BACK_F_NOUNDEFFILTER;
+		}
+		break;
+
+#ifdef SLAPD_META_CLIENT_PR
+	case LDAP_BACK_CFG_CLIENT_PR:
+		if ( strcasecmp( c->argv[ 1 ], "accept-unsolicited" ) == 0 ) {
+			mc->mc_ps = META_CLIENT_PR_ACCEPT_UNSOLICITED;
+
+		} else if ( strcasecmp( c->argv[ 1 ], "disable" ) == 0 ) {
+			mc->mc_ps = META_CLIENT_PR_DISABLE;
+
+		} else if ( lutil_atoi( &mc->mc_ps, c->argv[ 1 ] ) || mc->mc_ps < -1 ) {
+			snprintf( c->cr_msg, sizeof( c->cr_msg ),
+				"unable to parse client-pr {accept-unsolicited|disable|<size>}: \"%s\"",
+				c->argv[ 1 ] );
+			Debug( LDAP_DEBUG_ANY, "%s: %s.\n", c->log, c->cr_msg );
+			return( 1 );
+		}
+		break;
+#endif /* SLAPD_META_CLIENT_PR */
+
+	case LDAP_BACK_CFG_KEEPALIVE: {
+		struct berval bv;
+		ber_str2bv( c->argv[1], 0, 1, &bv );
+		slap_keepalive_parse( &bv, &mt->mt_tls.sb_keepalive, 0, 0, 0 );
+		}
+		break;
+
+	case LDAP_BACK_CFG_TCP_USER_TIMEOUT:
+		mt->mt_tls.sb_tcp_user_timeout = c->value_uint;
+		break;
+
+	/* anything else */
+	default:
+		return SLAP_CONF_UNKNOWN;
+	}
+
+	return rc;
+}
+
+int
+asyncmeta_back_init_cf( BackendInfo *bi )
+{
+	int			rc;
+
+	/* Make sure we don't exceed the bits reserved for userland */
+	config_check_userland( LDAP_BACK_CFG_LAST );
+
+	bi->bi_cf_ocs = a_metaocs;
+
+	rc = config_register_schema( a_metacfg, a_metaocs );
+	if ( rc ) {
+		return rc;
+	}
+
+	return 0;
+}
diff --git a/servers/slapd/back-asyncmeta/conn.c b/servers/slapd/back-asyncmeta/conn.c
new file mode 100644
index 0000000..986d1ca
--- /dev/null
+++ b/servers/slapd/back-asyncmeta/conn.c
@@ -0,0 +1,1184 @@
+/* conn.c - handles connections to remote targets */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016-2022 The OpenLDAP Foundation.
+ * Portions Copyright 2016 Symas Corporation.
+ * 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 developed by Symas Corporation
++ * based on back-meta module for inclusion in OpenLDAP Software.
++ * This work was sponsored by Ericsson. */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/errno.h>
+#include <ac/socket.h>
+#include <ac/string.h>
+#include "slap.h"
+#include "../../../libraries/libldap/ldap-int.h"
+#include "../back-ldap/back-ldap.h"
+#include "back-asyncmeta.h"
+
+/*
+ * asyncmeta_conn_alloc
+ *
+ * Allocates a connection structure, making room for all the referenced targets
+ */
+static a_metaconn_t *
+asyncmeta_conn_alloc(
+	a_metainfo_t	*mi)
+{
+	a_metaconn_t	*mc;
+	int		ntargets = mi->mi_ntargets;
+
+	assert( ntargets > 0 );
+
+	/* malloc all in one */
+	mc = ( a_metaconn_t * )ch_calloc( 1, sizeof( a_metaconn_t ) + ntargets * sizeof( a_metasingleconn_t ));
+	if ( mc == NULL ) {
+		return NULL;
+	}
+
+	mc->mc_info = mi;
+	ldap_pvt_thread_mutex_init( &mc->mc_om_mutex);
+	mc->mc_authz_target = META_BOUND_NONE;
+	mc->mc_conns = (a_metasingleconn_t *)(mc+1);
+	return mc;
+}
+
+/*
+ * asyncmeta_init_one_conn
+ *
+ * Initializes one connection
+ */
+int
+asyncmeta_init_one_conn(
+	Operation		*op,
+	SlapReply		*rs,
+	a_metaconn_t		*mc,
+	int			candidate,
+	int			ispriv,
+	ldap_back_send_t	sendok,
+	int			dolock)
+{
+	a_metainfo_t		*mi = mc->mc_info;
+	a_metatarget_t		*mt = mi->mi_targets[ candidate ];
+	a_metasingleconn_t	*msc = NULL;
+	int			version;
+	a_dncookie		dc;
+	int			isauthz = ( candidate == mc->mc_authz_target );
+	int			do_return = 0;
+#ifdef HAVE_TLS
+	int			is_ldaps = 0;
+	int			do_start_tls = 0;
+#endif /* HAVE_TLS */
+
+	/* 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 ( mt->mt_isquarantined ) {
+		slap_retry_info_t	*ri = &mt->mt_quarantine;
+		int			dont_retry = 0;
+
+		if ( mt->mt_quarantine.ri_interval ) {
+			ldap_pvt_thread_mutex_lock( &mt->mt_quarantine_mutex );
+			dont_retry = ( mt->mt_isquarantined > LDAP_BACK_FQ_NO );
+			if ( dont_retry ) {
+				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 asyncmeta_init_one_conn[%d]: quarantine " "retry block #%d try #%d.\n",
+					      op->o_log_prefix,
+					      candidate, ri->ri_idx,
+					      ri->ri_count );
+
+					mt->mt_isquarantined = LDAP_BACK_FQ_RETRYING;
+				}
+
+			}
+			ldap_pvt_thread_mutex_unlock( &mt->mt_quarantine_mutex );
+		}
+
+		if ( dont_retry ) {
+			rs->sr_err = LDAP_UNAVAILABLE;
+			rs->sr_text = "Target is quarantined";
+			Debug( LDAP_DEBUG_ANY, "%s asyncmeta_init_one_conn: Target is quarantined\n",
+			       op->o_log_prefix );
+			if ( op->o_conn && ( sendok & LDAP_BACK_SENDERR ) ) {
+					send_ldap_result( op, rs );
+			}
+			return rs->sr_err;
+		}
+	}
+		msc = &mc->mc_conns[candidate];
+	/*
+	 * Already init'ed
+	 */
+	if ( LDAP_BACK_CONN_ISBOUND( msc )
+		|| LDAP_BACK_CONN_ISANON( msc ) )
+	{
+		assert( msc->msc_ld != NULL );
+		rs->sr_err = LDAP_SUCCESS;
+		do_return = 1;
+
+	} else if ( META_BACK_CONN_CREATING( msc )
+		|| LDAP_BACK_CONN_BINDING( msc ) )
+	{
+		rs->sr_err = LDAP_SUCCESS;
+		do_return = 1;
+
+	} else if ( META_BACK_CONN_INITED( msc ) ) {
+		assert( msc->msc_ld != NULL );
+		rs->sr_err = LDAP_SUCCESS;
+		do_return = 1;
+
+	} else {
+		/*
+		 * creating...
+		 */
+		META_BACK_CONN_CREATING_SET( msc );
+	}
+
+	if ( do_return ) {
+		if ( rs->sr_err != LDAP_SUCCESS
+			&& op->o_conn
+			&& ( sendok & LDAP_BACK_SENDERR ) )
+		{
+			send_ldap_result( op, rs );
+		}
+
+		return rs->sr_err;
+	}
+
+	assert( msc->msc_ld == NULL );
+
+	/*
+	 * Attempts to initialize the connection to the target ds
+	 */
+	ldap_pvt_thread_mutex_lock( &mt->mt_uri_mutex );
+
+	rs->sr_err = ldap_initialize( &msc->msc_ld, mt->mt_uri );
+#ifdef HAVE_TLS
+	is_ldaps = ldap_is_ldaps_url( mt->mt_uri );
+#endif /* HAVE_TLS */
+	ldap_pvt_thread_mutex_unlock( &mt->mt_uri_mutex );
+	if ( rs->sr_err != LDAP_SUCCESS ) {
+		Debug( LDAP_DEBUG_ANY, "%s asyncmeta_init_one_conn: ldap_initialize failed err=%d\n",
+		       op->o_log_prefix, rs->sr_err );
+		goto error_return;
+	}
+
+	ldap_set_option( msc->msc_ld, LDAP_OPT_KEEPCONN, LDAP_OPT_ON);
+
+	msc->msc_ldr = ldap_dup(msc->msc_ld);
+	if (!msc->msc_ldr) {
+		ldap_ld_free(msc->msc_ld, 0, NULL, NULL);
+		rs->sr_err = LDAP_NO_MEMORY;
+		goto error_return;
+	}
+
+	/*
+	 * Set LDAP version. This will always succeed: If the client
+	 * bound with a particular version, then so can we.
+	 */
+	if ( mt->mt_version != 0 ) {
+		version = mt->mt_version;
+
+	} else if ( op->o_conn->c_protocol != 0 ) {
+		version = op->o_conn->c_protocol;
+
+	} else {
+		version = LDAP_VERSION3;
+	}
+	ldap_set_option( msc->msc_ld, LDAP_OPT_PROTOCOL_VERSION, &version );
+	ldap_set_urllist_proc( msc->msc_ld, mt->mt_urllist_f, mt->mt_urllist_p );
+
+	/* automatically chase referrals ("chase-referrals [{yes|no}]" statement) */
+	ldap_set_option( msc->msc_ld, LDAP_OPT_REFERRALS,
+		META_BACK_TGT_CHASE_REFERRALS( mt ) ? LDAP_OPT_ON : LDAP_OPT_OFF );
+
+	slap_client_keepalive(msc->msc_ld, &mt->mt_tls.sb_keepalive);
+
+	if ( mt->mt_tls.sb_tcp_user_timeout > 0 ) {
+		ldap_set_option( msc->msc_ld, LDAP_OPT_TCP_USER_TIMEOUT,
+				 &mt->mt_tls.sb_tcp_user_timeout );
+	}
+
+#ifdef HAVE_TLS
+	{
+		slap_bindconf *sb = NULL;
+
+		if ( ispriv ) {
+			sb = &mt->mt_idassert.si_bc;
+		} else {
+			sb = &mt->mt_tls;
+		}
+
+		bindconf_tls_set( sb, msc->msc_ld );
+
+		if ( !is_ldaps ) {
+			if ( META_BACK_TGT_USE_TLS( mt )
+				|| ( op->o_conn->c_is_tls && META_BACK_TGT_PROPAGATE_TLS( mt ) ) )
+			{
+				do_start_tls = 1;
+			}
+		}
+	}
+
+	/* start TLS ("tls [try-]{start|propagate}" statement) */
+	if ( do_start_tls ) {
+#ifdef SLAP_STARTTLS_ASYNCHRONOUS
+		/*
+		 * use asynchronous StartTLS; in case, chase referral
+		 * FIXME: OpenLDAP does not return referral on StartTLS yet
+		 */
+		int		msgid;
+
+		rs->sr_err = ldap_start_tls( msc->msc_ld, NULL, NULL, &msgid );
+		if ( rs->sr_err == LDAP_SUCCESS ) {
+			LDAPMessage	*res = NULL;
+			int		rc, nretries = mt->mt_nretries;
+			struct timeval	tv;
+
+			LDAP_BACK_TV_SET( &tv );
+
+retry:;
+			rc = ldap_result( msc->msc_ld, msgid, LDAP_MSG_ALL, &tv, &res );
+			switch ( rc ) {
+			case -1:
+				rs->sr_err = LDAP_OTHER;
+				break;
+
+			case 0:
+				if ( nretries != 0 ) {
+					if ( nretries > 0 ) {
+						nretries--;
+					}
+					LDAP_BACK_TV_SET( &tv );
+					goto retry;
+				}
+				rs->sr_err = LDAP_OTHER;
+				break;
+
+			default:
+				/* only touch when activity actually took place... */
+				if ( mi->mi_idle_timeout != 0 ) {
+					asyncmeta_set_msc_time(msc);
+				}
+				break;
+			}
+
+			if ( rc == LDAP_RES_EXTENDED ) {
+				struct berval	*data = NULL;
+
+				/* NOTE: right now, data is unused, so don't get it */
+				rs->sr_err = ldap_parse_extended_result( msc->msc_ld,
+					res, NULL, NULL /* &data */ , 0 );
+				if ( rs->sr_err == LDAP_SUCCESS ) {
+					int		err;
+
+					/* FIXME: matched? referrals? response controls? */
+					rs->sr_err = ldap_parse_result( msc->msc_ld,
+						res, &err, NULL, NULL, NULL, NULL, 1 );
+					res = NULL;
+
+					if ( rs->sr_err == LDAP_SUCCESS ) {
+
+						rs->sr_err = err;
+					}
+					rs->sr_err = slap_map_api2result( rs );
+
+					/* FIXME: in case a referral
+					 * is returned, should we try
+					 * using it instead of the
+					 * configured URI? */
+					if ( rs->sr_err == LDAP_SUCCESS ) {
+						rs->sr_err = ldap_install_tls( msc->msc_ld );
+
+					} else if ( rs->sr_err == LDAP_REFERRAL ) {
+						/* FIXME: LDAP_OPERATIONS_ERROR? */
+						rs->sr_err = LDAP_OTHER;
+						rs->sr_text = "Unwilling to chase referral "
+							"returned by Start TLS exop";
+					}
+
+					if ( data ) {
+						ber_bvfree( data );
+					}
+				}
+
+			} else {
+				rs->sr_err = LDAP_OTHER;
+			}
+
+			if ( res != NULL ) {
+				ldap_msgfree( res );
+			}
+		}
+#else /* ! SLAP_STARTTLS_ASYNCHRONOUS */
+		/*
+		 * use synchronous StartTLS
+		 */
+		rs->sr_err = ldap_start_tls_s( msc->msc_ld, NULL, NULL );
+#endif /* ! SLAP_STARTTLS_ASYNCHRONOUS */
+		if (rs->sr_err != LDAP_SUCCESS) {
+			Debug( LDAP_DEBUG_ANY, "%s asyncmeta_init_one_conn: ldap_start_tls_s failed err=%d\n",
+			       op->o_log_prefix, rs->sr_err );
+		}
+		/* 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 */
+		if ( rs->sr_err == LDAP_SERVER_DOWN
+			|| ( rs->sr_err != LDAP_SUCCESS
+				&& META_BACK_TGT_TLS_CRITICAL( mt ) ) )
+		{
+
+#ifdef DEBUG_205
+			Debug( LDAP_DEBUG_ANY,
+				"### %s asyncmeta_init_one_conn(TLS) "
+				"ldap_unbind_ext[%d] ld=%p\n",
+				op->o_log_prefix, candidate,
+				(void *)msc->msc_ld );
+#endif /* DEBUG_205 */
+
+			/* need to trash a failed Start TLS */
+			asyncmeta_clear_one_msc( op, mc, candidate, 1, __FUNCTION__ );
+			goto error_return;
+		}
+	}
+#endif /* HAVE_TLS */
+	/*
+	 * Set the network timeout if set
+	 */
+	if ( mt->mt_network_timeout != 0 ) {
+		struct timeval  network_timeout;
+		network_timeout.tv_sec = 0;
+		network_timeout.tv_usec = mt->mt_network_timeout*1000;
+
+		ldap_set_option( msc->msc_ld, LDAP_OPT_NETWORK_TIMEOUT,
+				 (void *)&network_timeout );
+	}
+
+	/*
+	 * If the connection DN is not null, an attempt to rewrite it is made
+	 */
+
+	if ( ispriv ) {
+		if ( !BER_BVISNULL( &mt->mt_idassert_authcDN ) ) {
+			ber_bvreplace( &msc->msc_bound_ndn, &mt->mt_idassert_authcDN );
+			if ( !BER_BVISNULL( &mt->mt_idassert_passwd ) ) {
+				if ( !BER_BVISNULL( &msc->msc_cred ) ) {
+					memset( msc->msc_cred.bv_val, 0,
+						msc->msc_cred.bv_len );
+				}
+				ber_bvreplace( &msc->msc_cred, &mt->mt_idassert_passwd );
+			}
+			LDAP_BACK_CONN_ISIDASSERT_SET( msc );
+
+		} else {
+			ber_bvreplace( &msc->msc_bound_ndn, &slap_empty_bv );
+		}
+
+	} else {
+		if ( !BER_BVISNULL( &msc->msc_cred ) ) {
+			memset( msc->msc_cred.bv_val, 0, msc->msc_cred.bv_len );
+			ber_memfree_x( msc->msc_cred.bv_val, NULL );
+			BER_BVZERO( &msc->msc_cred );
+		}
+		if ( !BER_BVISNULL( &msc->msc_bound_ndn ) ) {
+			ber_memfree_x( msc->msc_bound_ndn.bv_val, NULL );
+			BER_BVZERO( &msc->msc_bound_ndn );
+		}
+		if ( !BER_BVISEMPTY( &op->o_ndn )
+			&& isauthz )
+		{
+			dc.op = op;
+			dc.target = mt;
+			dc.memctx = NULL;
+			dc.to_from = MASSAGE_REQ;
+
+			/*
+			 * Rewrite the bind dn if needed
+			 */
+			asyncmeta_dn_massage( &dc, &op->o_conn->c_dn, &msc->msc_bound_ndn );
+
+			/* copy the DN if needed */
+			if ( msc->msc_bound_ndn.bv_val == op->o_conn->c_dn.bv_val ) {
+				ber_dupbv( &msc->msc_bound_ndn, &op->o_conn->c_dn );
+			}
+		} else {
+			ber_dupbv( &msc->msc_bound_ndn, (struct berval *)&slap_empty_bv );
+		}
+	}
+	assert( !BER_BVISNULL( &msc->msc_bound_ndn ) );
+
+error_return:;
+
+	if (msc != NULL) {
+		META_BACK_CONN_CREATING_CLEAR( msc );
+	}
+	if ( rs->sr_err == LDAP_SUCCESS && msc != NULL) {
+		META_BACK_CONN_INITED_SET( msc );
+	}
+
+	if ( rs->sr_err != LDAP_SUCCESS ) {
+		rs->sr_err = slap_map_api2result( rs );
+		if ( sendok & LDAP_BACK_SENDERR ) {
+			send_ldap_result( op, rs );
+		}
+	}
+	return rs->sr_err;
+}
+
+
+static int
+asyncmeta_get_candidate(
+	Operation	*op,
+	SlapReply	*rs,
+	struct berval	*ndn )
+{
+	a_metainfo_t	*mi = ( a_metainfo_t * )op->o_bd->be_private;
+	long		candidate;
+
+	/*
+	 * tries to get a unique candidate
+	 * (takes care of default target)
+	 */
+	candidate = asyncmeta_select_unique_candidate( mi, ndn );
+
+	/*
+	 * if any is found, inits the connection
+	 */
+	if ( candidate == META_TARGET_NONE ) {
+		rs->sr_err = LDAP_NO_SUCH_OBJECT;
+		rs->sr_text = "No suitable candidate target found";
+
+	} else {
+		rs->sr_err = LDAP_SUCCESS;
+	}
+
+	return candidate;
+}
+
+
+/*
+ * asyncmeta_getconn
+ *
+ * Prepares the connection structure
+ *
+ * RATIONALE:
+ *
+ * - determine what DN is being requested:
+ *
+ *	op	requires candidate	checks
+ *
+ *	add	unique			parent of o_req_ndn
+ *	bind	unique^*[/all]		o_req_ndn [no check]
+ *	compare	unique^+		o_req_ndn
+ *	delete	unique			o_req_ndn
+ *	modify	unique			o_req_ndn
+ *	search	any			o_req_ndn
+ *	modrdn	unique[, unique]	o_req_ndn[, orr_nnewSup]
+ *
+ * - for ops that require the candidate to be unique, in case of multiple
+ *   occurrences an internal search with sizeLimit=1 is performed
+ *   if a unique candidate can actually be determined.  If none is found,
+ *   the operation aborts; if multiple are found, the default target
+ *   is used if defined and candidate; otherwise the operation aborts.
+ *
+ * *^note: actually, the bind operation is handled much like a search;
+ *   i.e. the bind is broadcast to all candidate targets.
+ *
+ * +^note: actually, the compare operation is handled much like a search;
+ *   i.e. the compare is broadcast to all candidate targets, while checking
+ *   that exactly none (noSuchObject) or one (TRUE/FALSE/UNDEFINED) is
+ *   returned.
+ */
+a_metaconn_t *
+asyncmeta_getconn(
+	Operation 		*op,
+	SlapReply		*rs,
+	SlapReply               *candidates,
+	int 			*candidate,
+	ldap_back_send_t	sendok,
+	int                     alloc_new)
+{
+	a_metainfo_t	*mi = ( a_metainfo_t * )op->o_bd->be_private;
+	a_metaconn_t	*mc = NULL,
+			mc_curr = {{ 0 }};
+	int		cached = META_TARGET_NONE,
+			i = META_TARGET_NONE,
+			err = LDAP_SUCCESS,
+			new_conn = 0,
+			ncandidates = 0;
+
+
+	meta_op_type	op_type = META_OP_REQUIRE_SINGLE;
+	enum		{
+		META_DNTYPE_ENTRY,
+		META_DNTYPE_PARENT,
+		META_DNTYPE_NEWPARENT
+	}		dn_type = META_DNTYPE_ENTRY;
+	struct berval	ndn = op->o_req_ndn,
+			pndn;
+
+	if (alloc_new > 0) {
+		mc = asyncmeta_conn_alloc(mi);
+		new_conn = 0;
+	} else {
+		mc = asyncmeta_get_next_mc(mi);
+	}
+
+	ldap_pvt_thread_mutex_lock(&mc->mc_om_mutex);
+	/* Internal searches are privileged and shared. So is root. */
+	if ( ( !BER_BVISEMPTY( &op->o_ndn ) && META_BACK_PROXYAUTHZ_ALWAYS( mi ) )
+		|| ( BER_BVISEMPTY( &op->o_ndn ) && META_BACK_PROXYAUTHZ_ANON( mi ) )
+		|| op->o_do_not_cache || be_isroot( op ) )
+	{
+		LDAP_BACK_CONN_ISPRIV_SET( &mc_curr );
+		LDAP_BACK_PCONN_ROOTDN_SET( &mc_curr, op );
+
+	} else if ( BER_BVISEMPTY( &op->o_ndn ) && META_BACK_PROXYAUTHZ_NOANON( mi ) )
+	{
+		LDAP_BACK_CONN_ISANON_SET( &mc_curr );
+		LDAP_BACK_PCONN_ANON_SET( &mc_curr, op );
+
+	} else {
+		/* Explicit binds must not be shared */
+		if ( !BER_BVISEMPTY( &op->o_ndn )
+			|| op->o_tag == LDAP_REQ_BIND
+			|| SLAP_IS_AUTHZ_BACKEND( op ) )
+		{
+			//mc_curr.mc_conn = op->o_conn;
+
+		} else {
+			LDAP_BACK_CONN_ISANON_SET( &mc_curr );
+			LDAP_BACK_PCONN_ANON_SET( &mc_curr, op );
+		}
+	}
+
+	switch ( op->o_tag ) {
+	case LDAP_REQ_ADD:
+		/* if we go to selection, the entry must not exist,
+		 * and we must be able to resolve the parent */
+		dn_type = META_DNTYPE_PARENT;
+		dnParent( &ndn, &pndn );
+		break;
+
+	case LDAP_REQ_MODRDN:
+		/* if nnewSuperior is not NULL, it must resolve
+		 * to the same candidate as the req_ndn */
+		if ( op->orr_nnewSup ) {
+			dn_type = META_DNTYPE_NEWPARENT;
+		}
+		break;
+
+	case LDAP_REQ_BIND:
+		/* if bound as rootdn, the backend must bind to all targets
+		 * with the administrative identity
+		 * (unless pseoudoroot-bind-defer is TRUE) */
+		if ( op->orb_method == LDAP_AUTH_SIMPLE && be_isroot_pw( op ) ) {
+			op_type = META_OP_REQUIRE_ALL;
+		}
+		break;
+
+	case LDAP_REQ_COMPARE:
+	case LDAP_REQ_DELETE:
+	case LDAP_REQ_MODIFY:
+		/* just a unique candidate */
+		break;
+
+	case LDAP_REQ_SEARCH:
+		/* allow multiple candidates for the searchBase */
+		op_type = META_OP_ALLOW_MULTIPLE;
+		break;
+
+	default:
+		/* right now, just break (exop?) */
+		break;
+	}
+
+	/*
+	 * require all connections ...
+	 */
+	if ( op_type == META_OP_REQUIRE_ALL ) {
+		if ( LDAP_BACK_CONN_ISPRIV( &mc_curr ) ) {
+			LDAP_BACK_CONN_ISPRIV_SET( mc );
+
+		} else if ( LDAP_BACK_CONN_ISANON( &mc_curr ) ) {
+			LDAP_BACK_CONN_ISANON_SET( mc );
+		}
+
+		for ( i = 0; i < mi->mi_ntargets; i++ ) {
+			/*
+			 * The target is activated; if needed, it is
+			 * also init'd
+			 */
+			candidates[ i ].sr_err = asyncmeta_init_one_conn( op,
+				rs, mc, i, LDAP_BACK_CONN_ISPRIV( &mc_curr ),
+				LDAP_BACK_DONTSEND, !new_conn );
+			if ( candidates[ i ].sr_err == LDAP_SUCCESS ) {
+				if ( new_conn && ( sendok & LDAP_BACK_BINDING ) ) {
+					LDAP_BACK_CONN_BINDING_SET( &mc->mc_conns[ i ] );
+				}
+				META_CANDIDATE_SET( &candidates[ i ] );
+				ncandidates++;
+
+			} else {
+
+				/*
+				 * FIXME: in case one target cannot
+				 * be init'd, should the other ones
+				 * be tried?
+				 */
+				META_CANDIDATE_RESET( &candidates[ i ] );
+				err = candidates[ i ].sr_err;
+				continue;
+			}
+		}
+
+		if ( ncandidates == 0 ) {
+			rs->sr_err = LDAP_NO_SUCH_OBJECT;
+			rs->sr_text = "Unable to select valid candidates";
+
+			if ( sendok & LDAP_BACK_SENDERR ) {
+				if ( rs->sr_err == LDAP_NO_SUCH_OBJECT ) {
+					rs->sr_matched = mi->mi_suffix.bv_val;
+				}
+				send_ldap_result( op, rs );
+				rs->sr_matched = NULL;
+			}
+			ldap_pvt_thread_mutex_unlock(&mc->mc_om_mutex);
+			if ( alloc_new > 0) {
+				asyncmeta_back_conn_free( mc );
+			}
+			return NULL;
+		}
+
+		goto done;
+	}
+
+	/*
+	 * looks in cache, if any
+	 */
+	if ( mi->mi_cache.ttl != META_DNCACHE_DISABLED ) {
+		cached = i = asyncmeta_dncache_get_target( &mi->mi_cache, &op->o_req_ndn );
+	}
+
+	if ( op_type == META_OP_REQUIRE_SINGLE ) {
+		int			j;
+
+		for ( j = 0; j < mi->mi_ntargets; j++ ) {
+			META_CANDIDATE_RESET( &candidates[ j ] );
+		}
+
+		/*
+		 * tries to get a unique candidate
+		 * (takes care of default target)
+		 */
+		if ( i == META_TARGET_NONE ) {
+			i = asyncmeta_get_candidate( op, rs, &ndn );
+
+			if ( rs->sr_err == LDAP_NO_SUCH_OBJECT && dn_type == META_DNTYPE_PARENT ) {
+				i = asyncmeta_get_candidate( op, rs, &pndn );
+			}
+
+			if ( i < 0 || rs->sr_err != LDAP_SUCCESS ) {
+				if ( sendok & LDAP_BACK_SENDERR ) {
+					if ( rs->sr_err == LDAP_NO_SUCH_OBJECT ) {
+						rs->sr_matched = mi->mi_suffix.bv_val;
+					}
+					send_ldap_result( op, rs );
+					rs->sr_matched = NULL;
+				}
+				ldap_pvt_thread_mutex_unlock(&mc->mc_om_mutex);
+				if ( mc != NULL && alloc_new ) {
+					asyncmeta_back_conn_free( mc );
+				}
+				return NULL;
+			}
+		}
+
+		if ( dn_type == META_DNTYPE_NEWPARENT && asyncmeta_get_candidate( op, rs, op->orr_nnewSup ) != i )
+		{
+			rs->sr_err = LDAP_UNWILLING_TO_PERFORM;
+			rs->sr_text = "Cross-target rename not supported";
+			if ( sendok & LDAP_BACK_SENDERR ) {
+				send_ldap_result( op, rs );
+			}
+			ldap_pvt_thread_mutex_unlock(&mc->mc_om_mutex);
+			if ( mc != NULL && alloc_new > 0 ) {
+				asyncmeta_back_conn_free( mc );
+			}
+			return NULL;
+		}
+
+		Debug( LDAP_DEBUG_TRACE,
+		       "==>asyncmeta__getconn: got target=%d for ndn=\"%s\" from cache\n",
+		       i, op->o_req_ndn.bv_val );
+			if ( LDAP_BACK_CONN_ISPRIV( &mc_curr ) ) {
+				LDAP_BACK_CONN_ISPRIV_SET( mc );
+
+			} else if ( LDAP_BACK_CONN_ISANON( &mc_curr ) ) {
+				LDAP_BACK_CONN_ISANON_SET( mc );
+			}
+
+		/*
+		 * Clear all other candidates
+		 */
+			( void )asyncmeta_clear_unused_candidates( op, i , mc, candidates);
+
+		/*
+		 * The target is activated; if needed, it is
+		 * also init'd. In case of error, asyncmeta_init_one_conn
+		 * sends the appropriate result.
+		 */
+		err = asyncmeta_init_one_conn( op, rs, mc, i,
+			LDAP_BACK_CONN_ISPRIV( &mc_curr ), sendok, !new_conn );
+		if ( err != LDAP_SUCCESS ) {
+			/*
+			 * FIXME: in case one target cannot
+			 * be init'd, should the other ones
+			 * be tried?
+			 */
+			META_CANDIDATE_RESET( &candidates[ i ] );
+			ldap_pvt_thread_mutex_unlock(&mc->mc_om_mutex);
+			if ( mc != NULL && alloc_new > 0 ) {
+				asyncmeta_back_conn_free( mc );
+			}
+			return NULL;
+		}
+
+		candidates[ i ].sr_err = LDAP_SUCCESS;
+		META_CANDIDATE_SET( &candidates[ i ] );
+		ncandidates++;
+
+		if ( candidate ) {
+			*candidate = i;
+		}
+
+	/*
+	 * if no unique candidate ...
+	 */
+	} else {
+	if ( LDAP_BACK_CONN_ISPRIV( &mc_curr ) ) {
+		LDAP_BACK_CONN_ISPRIV_SET( mc );
+
+	} else if ( LDAP_BACK_CONN_ISANON( &mc_curr ) ) {
+		LDAP_BACK_CONN_ISANON_SET( mc );
+	}
+
+		for ( i = 0; i < mi->mi_ntargets; i++ ) {
+			a_metatarget_t		*mt = mi->mi_targets[ i ];
+
+			META_CANDIDATE_RESET( &candidates[ i ] );
+
+			if ( i == cached
+				|| asyncmeta_is_candidate( mt, &op->o_req_ndn,
+					op->o_tag == LDAP_REQ_SEARCH ? op->ors_scope : LDAP_SCOPE_SUBTREE ) )
+			{
+
+				/*
+				 * The target is activated; if needed, it is
+				 * also init'd
+				 */
+				int lerr = asyncmeta_init_one_conn( op, rs, mc, i,
+					LDAP_BACK_CONN_ISPRIV( &mc_curr ),
+					LDAP_BACK_DONTSEND, !new_conn );
+				candidates[ i ].sr_err = lerr;
+				if ( lerr == LDAP_SUCCESS ) {
+					META_CANDIDATE_SET( &candidates[ i ] );
+					ncandidates++;
+
+					Debug( LDAP_DEBUG_TRACE, "%s: asyncmeta_getconn[%d]\n",
+						op->o_log_prefix, i );
+
+				} else if ( lerr == LDAP_UNAVAILABLE && !META_BACK_ONERR_STOP( mi ) ) {
+					META_CANDIDATE_SET( &candidates[ i ] );
+
+					Debug( LDAP_DEBUG_TRACE, "%s: asyncmeta_getconn[%d] %s\n",
+						op->o_log_prefix, i,
+						mt->mt_isquarantined != LDAP_BACK_FQ_NO ? "quarantined" : "unavailable" );
+
+				} else {
+
+					/*
+					 * FIXME: in case one target cannot
+					 * be init'd, should the other ones
+					 * be tried?
+					 */
+					/* leave the target candidate, but record the error for later use */
+					err = lerr;
+
+					if ( lerr == LDAP_UNAVAILABLE && mt->mt_isquarantined != LDAP_BACK_FQ_NO ) {
+						Debug( LDAP_DEBUG_TRACE, "%s: asyncmeta_getconn[%d] quarantined err=%d\n",
+							op->o_log_prefix, i, lerr );
+
+					} else {
+						Debug( LDAP_DEBUG_ANY, "%s: asyncmeta_getconn[%d] failed err=%d\n",
+							op->o_log_prefix, i, lerr );
+					}
+
+					if ( META_BACK_ONERR_STOP( mi ) ) {
+						if ( sendok & LDAP_BACK_SENDERR ) {
+							send_ldap_result( op, rs );
+						}
+						ldap_pvt_thread_mutex_unlock(&mc->mc_om_mutex);
+						if ( alloc_new > 0 ) {
+							asyncmeta_back_conn_free( mc );
+
+						}
+						return NULL;
+					}
+
+					continue;
+				}
+
+			}
+		}
+
+		if ( ncandidates == 0 ) {
+			if ( rs->sr_err == LDAP_SUCCESS ) {
+				rs->sr_err = LDAP_NO_SUCH_OBJECT;
+				rs->sr_text = "Unable to select valid candidates";
+			}
+
+			if ( sendok & LDAP_BACK_SENDERR ) {
+				if ( rs->sr_err == LDAP_NO_SUCH_OBJECT ) {
+					rs->sr_matched = mi->mi_suffix.bv_val;
+				}
+				send_ldap_result( op, rs );
+				rs->sr_matched = NULL;
+			}
+			if ( alloc_new > 0 ) {
+				asyncmeta_back_conn_free( mc );
+
+			}
+			ldap_pvt_thread_mutex_unlock(&mc->mc_om_mutex);
+			return NULL;
+		}
+	}
+
+done:;
+	rs->sr_err = LDAP_SUCCESS;
+	rs->sr_text = NULL;
+
+	if ( new_conn ) {
+		if ( !LDAP_BACK_PCONN_ISPRIV( mc ) ) {
+			/*
+			 * Err could be -1 in case a duplicate metaconn is inserted
+			 */
+			switch ( err ) {
+			case 0:
+				break;
+			default:
+				LDAP_BACK_CONN_CACHED_CLEAR( mc );
+				if ( LogTest( LDAP_DEBUG_ANY ) ) {
+					char buf[STRLENOF("4294967295U") + 1] = { 0 };
+					mi->mi_ldap_extra->connid2str( &mc->mc_base, buf, sizeof(buf) );
+
+					Debug( LDAP_DEBUG_ANY,
+						"%s asyncmeta_getconn: candidates=%d conn=%s insert failed\n",
+						op->o_log_prefix, ncandidates, buf );
+				}
+
+				asyncmeta_back_conn_free( mc );
+
+				rs->sr_err = LDAP_OTHER;
+				rs->sr_text = "Proxy bind collision";
+				if ( sendok & LDAP_BACK_SENDERR ) {
+					send_ldap_result( op, rs );
+				}
+				return NULL;
+			}
+		}
+
+		if ( LogTest( LDAP_DEBUG_TRACE ) ) {
+			char buf[STRLENOF("4294967295U") + 1] = { 0 };
+			mi->mi_ldap_extra->connid2str( &mc->mc_base, buf, sizeof(buf) );
+
+			Debug( LDAP_DEBUG_TRACE,
+				"%s asyncmeta_getconn: candidates=%d conn=%s inserted\n",
+				op->o_log_prefix, ncandidates, buf );
+		}
+
+	} else {
+		if ( LogTest( LDAP_DEBUG_TRACE ) ) {
+			char buf[STRLENOF("4294967295U") + 1] = { 0 };
+			mi->mi_ldap_extra->connid2str( &mc->mc_base, buf, sizeof(buf) );
+
+			Debug( LDAP_DEBUG_TRACE,
+				"%s asyncmeta_getconn: candidates=%d conn=%s fetched\n",
+				op->o_log_prefix, ncandidates, buf );
+		}
+	}
+	ldap_pvt_thread_mutex_unlock(&mc->mc_om_mutex);
+	return mc;
+}
+
+void
+asyncmeta_quarantine(
+	Operation	*op,
+	a_metainfo_t    *mi,
+	SlapReply	*rs,
+	int		candidate )
+{
+	a_metatarget_t		*mt = mi->mi_targets[ candidate ];
+
+	slap_retry_info_t	*ri = &mt->mt_quarantine;
+
+	ldap_pvt_thread_mutex_lock( &mt->mt_quarantine_mutex );
+
+	if ( rs->sr_err == LDAP_UNAVAILABLE ) {
+		time_t	new_last = slap_get_time();
+
+		switch ( mt->mt_isquarantined ) {
+		case LDAP_BACK_FQ_NO:
+			if ( ri->ri_last == new_last ) {
+				goto done;
+			}
+
+			Debug( LDAP_DEBUG_ANY,
+				"%s asyncmeta_quarantine[%d]: enter.\n",
+				op->o_log_prefix, candidate );
+
+			ri->ri_idx = 0;
+			ri->ri_count = 0;
+			break;
+
+		case LDAP_BACK_FQ_RETRYING:
+			Debug(LDAP_DEBUG_ANY,
+			      "%s asyncmeta_quarantine[%d]: block #%d try #%d failed.\n",
+			      op->o_log_prefix, candidate, 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:
+			goto done;
+		}
+
+		mt->mt_isquarantined = LDAP_BACK_FQ_YES;
+		ri->ri_last = new_last;
+
+	} else if ( mt->mt_isquarantined == LDAP_BACK_FQ_RETRYING ) {
+		Debug( LDAP_DEBUG_ANY,
+			"%s asyncmeta_quarantine[%d]: exit.\n",
+			op->o_log_prefix, candidate );
+
+		if ( mi->mi_quarantine_f ) {
+			(void)mi->mi_quarantine_f( mi, candidate,
+				mi->mi_quarantine_p );
+		}
+
+		ri->ri_count = 0;
+		ri->ri_idx = 0;
+		mt->mt_isquarantined = LDAP_BACK_FQ_NO;
+		mt->mt_timeout_ops = 0;
+	}
+
+done:;
+	ldap_pvt_thread_mutex_unlock( &mt->mt_quarantine_mutex );
+}
+
+a_metaconn_t *
+asyncmeta_get_next_mc( a_metainfo_t *mi )
+{
+	a_metaconn_t *mc = NULL;
+
+	ldap_pvt_thread_mutex_lock( &mi->mi_mc_mutex );
+	if (mi->mi_next_conn >= mi->mi_num_conns-1) {
+		mi->mi_next_conn = 0;
+	} else {
+		mi->mi_next_conn++;
+	}
+
+	mc = &mi->mi_conns[mi->mi_next_conn];
+	ldap_pvt_thread_mutex_unlock( &mi->mi_mc_mutex );
+	return mc;
+}
+
+int asyncmeta_start_listeners(a_metaconn_t *mc, SlapReply *candidates, bm_context_t *bc)
+{
+	int i;
+	for (i = 0; i < mc->mc_info->mi_ntargets; i++) {
+		asyncmeta_start_one_listener(mc, candidates, bc, i);
+	}
+	return LDAP_SUCCESS;
+}
+
+int asyncmeta_start_one_listener(a_metaconn_t *mc,
+				 SlapReply *candidates,
+				 bm_context_t *bc,
+				 int candidate)
+{
+	a_metasingleconn_t *msc;
+	ber_socket_t s;
+
+	msc = &mc->mc_conns[candidate];
+	if ( slapd_shutdown || !META_BACK_CONN_INITED( msc ) || msc->msc_ld == NULL
+	    || META_BACK_CONN_INVALID(msc) || !META_IS_CANDIDATE( &candidates[ candidate ] )) {
+		return LDAP_SUCCESS;
+	}
+	bc->msgids[candidate] = candidates[candidate].sr_msgid;
+	if ( msc->conn == NULL) {
+		ldap_get_option( msc->msc_ld, LDAP_OPT_DESC, &s );
+		if (s < 0) {
+			/* Todo a meaningful log pls */
+			return LDAP_OTHER;
+		}
+		msc->conn = connection_client_setup( s, asyncmeta_op_handle_result, mc );
+	}
+	connection_client_enable( msc->conn );
+	return LDAP_SUCCESS;
+}
+
+int
+asyncmeta_clear_one_msc(
+	Operation	*op,
+	a_metaconn_t	*mc,
+	int		candidate,
+	int             unbind,
+	const char *caller)
+{
+	a_metasingleconn_t *msc;
+	if (mc == NULL) {
+		return 0;
+	}
+	msc = &mc->mc_conns[candidate];
+	if ( LogTest( asyncmeta_debug ) ) {
+		char	time_buf[ SLAP_TEXT_BUFLEN ];
+		asyncmeta_get_timestamp(time_buf);
+		Debug( asyncmeta_debug, "[%s] Resetting msc: %p, msc_ld: %p, "
+		       "msc_bound_ndn: %s, msc->conn: %p, %s \n",
+		       time_buf, msc, msc->msc_ld, msc->msc_bound_ndn.bv_val,
+		       msc->conn, caller ? caller : "" );
+	}
+	msc->msc_mscflags = 0;
+	if (msc->conn) {
+		connection_client_stop( msc->conn );
+		msc->conn = NULL;
+	}
+
+	if ( msc->msc_ld != NULL ) {
+
+#ifdef DEBUG_205
+		Debug( LDAP_DEBUG_ANY, "### %s asyncmeta_clear_one_msc ldap_unbind_ext[%d] ld=%p\n",
+		       op ? op->o_log_prefix : "", candidate, (void *)msc->msc_ld );
+#endif /* DEBUG_205 */
+
+		ldap_unbind_ext( msc->msc_ld, NULL, NULL );
+		msc->msc_ld = NULL;
+		ldap_ld_free( msc->msc_ldr, 0, NULL, NULL );
+		msc->msc_ldr = NULL;
+	}
+
+	if ( !BER_BVISNULL( &msc->msc_bound_ndn ) ) {
+		ber_memfree_x( msc->msc_bound_ndn.bv_val, NULL );
+		BER_BVZERO( &msc->msc_bound_ndn );
+	}
+
+	if ( !BER_BVISNULL( &msc->msc_cred ) ) {
+		memset( msc->msc_cred.bv_val, 0, msc->msc_cred.bv_len );
+		ber_memfree_x( msc->msc_cred.bv_val, NULL );
+		BER_BVZERO( &msc->msc_cred );
+	}
+	msc->msc_time = 0;
+	msc->msc_binding_time = 0;
+	msc->msc_result_time = 0;
+	return 0;
+}
+
+void asyncmeta_get_timestamp(char *buf)
+{
+	struct timespec tp;
+	struct tm *ttm;
+	clock_gettime(CLOCK_REALTIME, &tp);
+	ttm = gmtime(&tp.tv_sec);
+	sprintf(buf, "%d:%d:%d.%ld", ttm->tm_hour, ttm->tm_min, ttm->tm_sec, tp.tv_nsec/1000);
+}
+
+int
+asyncmeta_reset_msc(
+	Operation	*op,
+	a_metaconn_t	*mc,
+	int		candidate,
+	int             unbind,
+	const char *caller)
+{
+	a_metasingleconn_t *msc = &mc->mc_conns[candidate];
+	if ( LogTest( asyncmeta_debug ) ) {
+		char	time_buf[ SLAP_TEXT_BUFLEN ];
+		asyncmeta_get_timestamp(time_buf);
+		Debug(asyncmeta_debug, "[%x] Will attempt to reset [%s] msc: %p, "
+		      "msc->msc_binding_time: %x, msc->msc_flags:%x %s\n",
+		      (unsigned int)slap_get_time(), time_buf, msc,
+		      (unsigned int)msc->msc_binding_time, msc->msc_mscflags, caller );
+	}
+	if (msc->msc_active <= 1 && mc->mc_active < 1) {
+		bm_context_t *om;
+		asyncmeta_clear_one_msc(NULL, mc, candidate, 0, caller);
+		/* set whatever's in the queue to invalid, so the timeout loop cleans it up,
+		 * but do not invalidate the current op*/
+		LDAP_STAILQ_FOREACH( om, &mc->mc_om_list, bc_next ) {
+			if (om->candidates[candidate].sr_msgid >= 0 && (om->op != op)) {
+				om->bc_invalid = 1;
+			}
+		}
+		return LDAP_SUCCESS;
+	} else {
+		META_BACK_CONN_INVALID_SET(msc);
+		Debug( asyncmeta_debug, "[%x] Failed to reset msc %p, msc_active=%d, mc_active=%d, %s\n",
+		       (unsigned int)slap_get_time(), msc, msc->msc_active, mc->mc_active, caller );
+	}
+	return LDAP_OTHER;
+}
+
+
+void asyncmeta_log_msc(a_metasingleconn_t *msc)
+{
+	ber_socket_t s = 0;
+	if (msc->msc_ld) {
+		ldap_get_option( msc->msc_ld, LDAP_OPT_DESC, &s );
+	}
+	Debug( asyncmeta_debug, "msc: %p, msc_ld: %p, msc_ld socket: %d, "
+	       "msc_bound_ndn: %s, msc->conn: %p\n", msc, msc->msc_ld,
+	       (int)s, msc->msc_bound_ndn.bv_val, msc->conn );
+}
+
+void asyncmeta_log_conns(a_metainfo_t *mi)
+{
+	a_metaconn_t *mc;
+	int i, j;
+	for (i = 0; i < mi->mi_num_conns; i++) {
+		mc = &mi->mi_conns[i];
+		Debug(asyncmeta_debug, "mc: %p, mc->pending_ops: %d\n", mc, mc->pending_ops);
+		for (j = 0; j < mi->mi_ntargets; j++ ) {
+			asyncmeta_log_msc(&mc->mc_conns[j]);
+		}
+
+	}
+}
diff --git a/servers/slapd/back-asyncmeta/delete.c b/servers/slapd/back-asyncmeta/delete.c
new file mode 100644
index 0000000..b91b1a5
--- /dev/null
+++ b/servers/slapd/back-asyncmeta/delete.c
@@ -0,0 +1,297 @@
+/* delete.c - delete request handler for back-asyncmeta */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016-2022 The OpenLDAP Foundation.
+ * Portions Copyright 2016 Symas Corporation.
+ * 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 developed by Symas Corporation
++ * based on back-meta module for inclusion in OpenLDAP Software.
++ * This work was sponsored by Ericsson. */
+
+#include "portable.h"
+
+#include <stdio.h>
+#include <ac/string.h>
+#include <ac/socket.h>
+#include "slap.h"
+#include "../../../libraries/liblber/lber-int.h"
+#include "../../../libraries/libldap/ldap-int.h"
+#include "../back-ldap/back-ldap.h"
+#include "back-asyncmeta.h"
+
+meta_search_candidate_t
+asyncmeta_back_delete_start(Operation *op,
+			    SlapReply *rs,
+			    a_metaconn_t *mc,
+			    bm_context_t *bc,
+			    int candidate,
+			    int do_lock)
+{
+	a_metainfo_t	*mi = mc->mc_info;
+	a_metatarget_t	*mt = mi->mi_targets[ candidate ];
+	struct berval	mdn = BER_BVNULL;
+	a_dncookie	dc;
+	int rc = 0;
+	LDAPControl	**ctrls = NULL;
+	meta_search_candidate_t retcode = META_SEARCH_CANDIDATE;
+	BerElement *ber = NULL;
+	a_metasingleconn_t	*msc = &mc->mc_conns[ candidate ];
+	SlapReply		*candidates = bc->candidates;
+	ber_int_t	msgid;
+
+	dc.op = op;
+	dc.target = mt;
+	dc.memctx = op->o_tmpmemctx;
+	dc.to_from = MASSAGE_REQ;
+
+	asyncmeta_dn_massage( &dc, &op->o_req_dn, &mdn );
+
+	asyncmeta_set_msc_time(msc);
+	ctrls = op->o_ctrls;
+	if ( asyncmeta_controls_add( op, rs, mc, candidate, bc->is_root, &ctrls ) != LDAP_SUCCESS )
+	{
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		retcode = META_SEARCH_ERR;
+		goto done;
+	}
+	/* someone might have reset the connection */
+	if (!( LDAP_BACK_CONN_ISBOUND( msc )
+	       || LDAP_BACK_CONN_ISANON( msc )) || msc->msc_ld == NULL ) {
+		Debug( asyncmeta_debug, "msc %p not initialized at %s:%d\n", msc, __FILE__, __LINE__ );
+		goto error_unavailable;
+	}
+	ber = ldap_build_delete_req( msc->msc_ld, mdn.bv_val, ctrls, NULL, &msgid);
+
+	if (!ber) {
+		Debug( asyncmeta_debug, "%s asyncmeta_back_delete_start: Operation encoding failed with errno %d\n",
+		       op->o_log_prefix, msc->msc_ld->ld_errno );
+		rs->sr_err = LDAP_OPERATIONS_ERROR;
+		rs->sr_text = "Failed to encode proxied request";
+		retcode = META_SEARCH_ERR;
+		goto done;
+	}
+
+	if (ber) {
+		struct timeval tv = {0, mt->mt_network_timeout*1000};
+		ber_socket_t s;
+		if (!( LDAP_BACK_CONN_ISBOUND( msc )
+		       || LDAP_BACK_CONN_ISANON( msc )) || msc->msc_ld == NULL ) {
+			Debug( asyncmeta_debug, "msc %p not initialized at %s:%d\n", msc, __FILE__, __LINE__ );
+			goto error_unavailable;
+		}
+
+		ldap_get_option( msc->msc_ld, LDAP_OPT_DESC, &s );
+		if (s < 0) {
+			Debug( asyncmeta_debug, "msc %p not initialized at %s:%d\n", msc, __FILE__, __LINE__ );
+			goto error_unavailable;
+		}
+
+		rc = ldap_int_poll( msc->msc_ld, s, &tv, 1);
+		if (rc < 0) {
+			Debug( asyncmeta_debug, "msc %p not writable within network timeout %s:%d\n", msc, __FILE__, __LINE__ );
+			if ((msc->msc_result_time + META_BACK_RESULT_INTERVAL) < slap_get_time()) {
+				rc = LDAP_SERVER_DOWN;
+			} else {
+				goto error_unavailable;
+			}
+		} else {
+			candidates[ candidate ].sr_msgid = msgid;
+			rc = ldap_send_initial_request( msc->msc_ld, LDAP_REQ_DELETE,
+							mdn.bv_val, ber, msgid );
+			if (rc == msgid)
+				rc = LDAP_SUCCESS;
+			else
+				rc = LDAP_SERVER_DOWN;
+			ber = NULL;
+		}
+
+		switch ( rc ) {
+		case LDAP_SUCCESS:
+			retcode = META_SEARCH_CANDIDATE;
+			asyncmeta_set_msc_time(msc);
+			goto done;
+
+		case LDAP_SERVER_DOWN:
+			/* do not lock if called from asyncmeta_handle_bind_result. Also do not reset the connection */
+			if (do_lock > 0) {
+				ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+				asyncmeta_reset_msc(NULL, mc, candidate, 0, __FUNCTION__);
+				ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			}
+			/* fall though*/
+		default:
+			Debug( asyncmeta_debug, "msc %p ldap_send_initial_request failed. %s:%d\n", msc, __FILE__, __LINE__ );
+			goto error_unavailable;
+		}
+	}
+
+error_unavailable:
+	if (ber)
+		ber_free(ber, 1);
+	switch (bc->nretries[candidate]) {
+	case -1: /* nretries = forever */
+		retcode = META_SEARCH_NEED_BIND;
+		ldap_pvt_thread_yield();
+		break;
+	case 0: /* no retries left */
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		rs->sr_err = LDAP_UNAVAILABLE;
+		rs->sr_text = "Unable to send delete request to target";
+		retcode = META_SEARCH_ERR;
+		break;
+	default: /* more retries left - try to rebind and go again */
+		retcode = META_SEARCH_NEED_BIND;
+		bc->nretries[candidate]--;
+		ldap_pvt_thread_yield();
+		break;
+	}
+done:
+	(void)mi->mi_ldap_extra->controls_free( op, rs, &ctrls );
+
+	if ( mdn.bv_val != op->o_req_dn.bv_val ) {
+		op->o_tmpfree( mdn.bv_val, op->o_tmpmemctx );
+	}
+
+	Debug( LDAP_DEBUG_TRACE, "%s <<< asyncmeta_back_delete_start[%p]=%d\n", op->o_log_prefix, msc, candidates[candidate].sr_msgid );
+	return retcode;
+}
+
+int
+asyncmeta_back_delete( Operation *op, SlapReply *rs )
+{
+	a_metainfo_t	*mi = ( a_metainfo_t * )op->o_bd->be_private;
+	a_metatarget_t	*mt;
+	a_metaconn_t	*mc;
+	int		rc, candidate = -1;
+	void *thrctx = op->o_threadctx;
+	bm_context_t *bc;
+	SlapReply *candidates;
+	time_t current_time = slap_get_time();
+
+	int max_pending_ops = (mi->mi_max_pending_ops == 0) ? META_BACK_CFG_MAX_PENDING_OPS : mi->mi_max_pending_ops;
+
+	Debug(LDAP_DEBUG_TRACE, "==> asyncmeta_back_delete: %s\n",
+	      op->o_req_dn.bv_val );
+
+	if (current_time > op->o_time) {
+		Debug(asyncmeta_debug, "==> asyncmeta_back_delete[%s]: o_time:[%ld], current time: [%ld]\n",
+		      op->o_log_prefix, op->o_time, current_time );
+	}
+
+	asyncmeta_new_bm_context(op, rs, &bc, mi->mi_ntargets, mi );
+	if (bc == NULL) {
+		rs->sr_err = LDAP_OTHER;
+		send_ldap_result(op, rs);
+		return rs->sr_err;
+	}
+
+	candidates = bc->candidates;
+	mc = asyncmeta_getconn( op, rs, candidates, &candidate, LDAP_BACK_DONTSEND, 0);
+	if ( !mc || rs->sr_err != LDAP_SUCCESS) {
+		send_ldap_result(op, rs);
+		return rs->sr_err;
+	}
+
+	mt = mi->mi_targets[ candidate ];
+	bc->timeout = mt->mt_timeout[ SLAP_OP_DELETE ];
+	bc->retrying = LDAP_BACK_RETRYING;
+	bc->sendok = ( LDAP_BACK_SENDRESULT | bc->retrying );
+	bc->stoptime = op->o_time + bc->timeout;
+	bc->bc_active = 1;
+
+	if (mc->pending_ops >= max_pending_ops) {
+		rs->sr_err = LDAP_BUSY;
+		rs->sr_text = "Maximum pending ops limit exceeded";
+		send_ldap_result(op, rs);
+		return rs->sr_err;
+	}
+
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	rc = asyncmeta_add_message_queue(mc, bc);
+	mc->mc_conns[candidate].msc_active++;
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+
+	if (rc != LDAP_SUCCESS) {
+		rs->sr_err = LDAP_BUSY;
+		rs->sr_text = "Maximum pending ops limit exceeded";
+		send_ldap_result(op, rs);
+		ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+		mc->mc_conns[candidate].msc_active--;
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+		goto finish;
+	}
+
+retry:
+	if (bc->timeout && bc->stoptime < slap_get_time()) {
+		int		timeout_err;
+		timeout_err = op->o_protocol >= LDAP_VERSION3 ?
+			LDAP_ADMINLIMIT_EXCEEDED : LDAP_OTHER;
+		rs->sr_err = timeout_err;
+		rs->sr_text = "Operation timed out before it was sent to target";
+		asyncmeta_error_cleanup(op, rs, bc, mc, candidate);
+		goto finish;
+	}
+
+	rc = asyncmeta_dobind_init_with_retry(op, rs, bc, mc, candidate);
+	switch (rc)
+	{
+	case META_SEARCH_CANDIDATE:
+		/* target is already bound, just send the request */
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_delete:  "
+		       "cnd=\"%d\"\n", op->o_log_prefix, candidate );
+
+		rc = asyncmeta_back_delete_start( op, rs, mc, bc, candidate, 1);
+		if (rc == META_SEARCH_ERR) {
+			asyncmeta_error_cleanup(op, rs, bc, mc, candidate);
+			goto finish;
+
+		} else if (rc == META_SEARCH_NEED_BIND) {
+			goto retry;
+		}
+		break;
+	case META_SEARCH_NOT_CANDIDATE:
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_delete: NOT_CANDIDATE "
+		       "cnd=\"%d\"\n", op->o_log_prefix, candidate );
+		asyncmeta_error_cleanup(op, rs, bc, mc, candidate);
+		goto finish;
+
+	case META_SEARCH_NEED_BIND:
+	case META_SEARCH_BINDING:
+			Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_delete: BINDING "
+			       "cnd=\"%d\" %p\n", op->o_log_prefix, candidate , &mc->mc_conns[candidate]);
+			/* Todo add the context to the message queue but do not send the request
+			   the receiver must send this when we are done binding */
+			/* question - how would do receiver know to which targets??? */
+			break;
+
+	case META_SEARCH_ERR:
+			Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_delete: ERR "
+			       "cnd=\"%d\"\n", op->o_log_prefix, candidate );
+			asyncmeta_error_cleanup(op, rs, bc, mc, candidate);
+			goto finish;
+		default:
+			assert( 0 );
+			break;
+		}
+
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	mc->mc_conns[candidate].msc_active--;
+	asyncmeta_start_one_listener(mc, candidates, bc, candidate);
+	bc->bc_active--;
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+	rs->sr_err = SLAPD_ASYNCOP;
+finish:
+	return rs->sr_err;
+}
diff --git a/servers/slapd/back-asyncmeta/dncache.c b/servers/slapd/back-asyncmeta/dncache.c
new file mode 100644
index 0000000..a588290
--- /dev/null
+++ b/servers/slapd/back-asyncmeta/dncache.c
@@ -0,0 +1,228 @@
+/* dncache.c - dn caching for back-asyncmeta */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016-2022 The OpenLDAP Foundation.
+ * Portions Copyright 2016 Symas Corporation.
+ * 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 developed by Symas Corporation
+ * based on back-meta module for inclusion in OpenLDAP Software.
+ * This work was sponsored by Ericsson. */
+
+#include "portable.h"
+
+#include <stdio.h>
+#include <ac/string.h>
+
+#include "slap.h"
+#include "../back-ldap/back-ldap.h"
+#include "back-asyncmeta.h"
+
+/*
+ * The dncache, at present, maps an entry to the target that holds it.
+ */
+
+typedef struct metadncacheentry_t {
+	struct berval	dn;
+	int 		target;
+
+	time_t 		lastupdated;
+} metadncacheentry_t;
+
+/*
+ * asyncmeta_dncache_cmp
+ *
+ * compares two struct metadncacheentry; used by avl stuff
+ * FIXME: modify avl stuff to delete an entry based on cmp
+ * (e.g. when ttl expired?)
+ */
+int
+asyncmeta_dncache_cmp(
+	const void	*c1,
+	const void	*c2 )
+{
+	metadncacheentry_t	*cc1 = ( metadncacheentry_t * )c1;
+	metadncacheentry_t	*cc2 = ( metadncacheentry_t * )c2;
+
+	/*
+	 * case sensitive, because the dn MUST be normalized
+	 */
+	return ber_bvcmp( &cc1->dn, &cc2->dn);
+}
+
+/*
+ * asyncmeta_dncache_dup
+ *
+ * returns -1 in case a duplicate struct metadncacheentry has been inserted;
+ * used by avl stuff
+ */
+int
+asyncmeta_dncache_dup(
+	void		*c1,
+	void		*c2 )
+{
+	metadncacheentry_t	*cc1 = ( metadncacheentry_t * )c1;
+	metadncacheentry_t	*cc2 = ( metadncacheentry_t * )c2;
+
+	/*
+	 * case sensitive, because the dn MUST be normalized
+	 */
+	return ( ber_bvcmp( &cc1->dn, &cc2->dn ) == 0 ) ? -1 : 0;
+}
+
+/*
+ * asyncmeta_dncache_get_target
+ *
+ * returns the target a dn belongs to, or -1 in case the dn is not
+ * in the cache
+ */
+int
+asyncmeta_dncache_get_target(
+	a_metadncache_t	*cache,
+	struct berval	*ndn )
+{
+	metadncacheentry_t	tmp_entry,
+				*entry;
+	int			target = META_TARGET_NONE;
+
+	assert( cache != NULL );
+	assert( ndn != NULL );
+
+	tmp_entry.dn = *ndn;
+	ldap_pvt_thread_mutex_lock( &cache->mutex );
+	entry = ( metadncacheentry_t * )ldap_avl_find( cache->tree,
+			( caddr_t )&tmp_entry, asyncmeta_dncache_cmp );
+
+	if ( entry != NULL ) {
+
+		/*
+		 * if cache->ttl < 0, cache never expires;
+		 * if cache->ttl = 0 no cache is used; shouldn't get here
+		 * else, cache is used with ttl
+		 */
+		if ( cache->ttl < 0 ) {
+			target = entry->target;
+
+		} else {
+			if ( entry->lastupdated+cache->ttl > slap_get_time() ) {
+				target = entry->target;
+			}
+		}
+	}
+	ldap_pvt_thread_mutex_unlock( &cache->mutex );
+
+	return target;
+}
+
+/*
+ * asyncmeta_dncache_update_entry
+ *
+ * updates target and lastupdated of a struct metadncacheentry if exists,
+ * otherwise it gets created; returns -1 in case of error
+ */
+int
+asyncmeta_dncache_update_entry(
+	a_metadncache_t	*cache,
+	struct berval	*ndn,
+	int 		target )
+{
+	metadncacheentry_t	*entry,
+				tmp_entry;
+	time_t			curr_time = 0L;
+	int			err = 0;
+
+	assert( cache != NULL );
+	assert( ndn != NULL );
+
+	/*
+	 * if cache->ttl < 0, cache never expires;
+	 * if cache->ttl = 0 no cache is used; shouldn't get here
+	 * else, cache is used with ttl
+	 */
+	if ( cache->ttl > 0 ) {
+		curr_time = slap_get_time();
+	}
+
+	tmp_entry.dn = *ndn;
+
+	ldap_pvt_thread_mutex_lock( &cache->mutex );
+	entry = ( metadncacheentry_t * )ldap_avl_find( cache->tree,
+			( caddr_t )&tmp_entry, asyncmeta_dncache_cmp );
+
+	if ( entry != NULL ) {
+		entry->target = target;
+		entry->lastupdated = curr_time;
+
+	} else {
+		entry = ch_malloc( sizeof( metadncacheentry_t ) + ndn->bv_len + 1 );
+		if ( entry == NULL ) {
+			err = -1;
+			goto error_return;
+		}
+
+		entry->dn.bv_len = ndn->bv_len;
+		entry->dn.bv_val = (char *)&entry[ 1 ];
+		AC_MEMCPY( entry->dn.bv_val, ndn->bv_val, ndn->bv_len );
+		entry->dn.bv_val[ ndn->bv_len ] = '\0';
+
+		entry->target = target;
+		entry->lastupdated = curr_time;
+
+		err = ldap_avl_insert( &cache->tree, ( caddr_t )entry,
+				asyncmeta_dncache_cmp, asyncmeta_dncache_dup );
+	}
+
+error_return:;
+	ldap_pvt_thread_mutex_unlock( &cache->mutex );
+
+	return err;
+}
+
+int
+asyncmeta_dncache_delete_entry(
+	a_metadncache_t	*cache,
+	struct berval	*ndn )
+{
+	metadncacheentry_t	*entry,
+				tmp_entry;
+
+	assert( cache != NULL );
+	assert( ndn != NULL );
+
+	tmp_entry.dn = *ndn;
+
+	ldap_pvt_thread_mutex_lock( &cache->mutex );
+	entry = ldap_avl_delete( &cache->tree, ( caddr_t )&tmp_entry,
+			asyncmeta_dncache_cmp );
+	ldap_pvt_thread_mutex_unlock( &cache->mutex );
+
+	if ( entry != NULL ) {
+		asyncmeta_dncache_free( ( void * )entry );
+	}
+
+	return 0;
+}
+
+/*
+ * meta_dncache_free
+ *
+ * frees an entry
+ *
+ */
+void
+asyncmeta_dncache_free(
+	void		*e )
+{
+	free( e );
+}
diff --git a/servers/slapd/back-asyncmeta/init.c b/servers/slapd/back-asyncmeta/init.c
new file mode 100644
index 0000000..5324907
--- /dev/null
+++ b/servers/slapd/back-asyncmeta/init.c
@@ -0,0 +1,468 @@
+/* init.c - initialization of a back-asyncmeta database */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016-2022 The OpenLDAP Foundation.
+ * Portions Copyright 2016 Symas Corporation.
+ * 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 developed by Symas Corporation
+ * based on back-meta module for inclusion in OpenLDAP Software.
+ * This work was sponsored by Ericsson. */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/string.h>
+#include <ac/socket.h>
+
+#include "slap.h"
+#include "slap-config.h"
+#include "../back-ldap/back-ldap.h"
+#include "back-asyncmeta.h"
+
+int asyncmeta_debug;
+
+int
+asyncmeta_back_open(
+	BackendInfo	*bi )
+{
+	/* FIXME: need to remove the pagedResults, and likely more... */
+	bi->bi_controls = slap_known_controls;
+
+	return 0;
+}
+
+int
+asyncmeta_back_initialize(
+	BackendInfo	*bi )
+{
+	int rc;
+	struct berval debugbv = BER_BVC("asyncmeta");
+
+	rc = slap_loglevel_get( &debugbv, &asyncmeta_debug );
+	if ( rc ) {
+		return rc;
+	}
+
+	bi->bi_flags =
+#if 0
+	/* this is not (yet) set essentially because back-meta does not
+	 * directly support extended operations... */
+#ifdef LDAP_DYNAMIC_OBJECTS
+		/* this is set because all the support a proxy has to provide
+		 * is the capability to forward the refresh exop, and to
+		 * pass thru entries that contain the dynamicObject class
+		 * and the entryTtl attribute */
+		SLAP_BFLAG_DYNAMIC |
+#endif /* LDAP_DYNAMIC_OBJECTS */
+#endif
+
+		/* back-meta recognizes RFC4525 increment;
+		 * let the remote server complain, if needed (ITS#5912) */
+		SLAP_BFLAG_INCREMENT;
+
+	bi->bi_open = asyncmeta_back_open;
+	bi->bi_config = 0;
+	bi->bi_close = 0;
+	bi->bi_destroy = 0;
+
+	bi->bi_db_init = asyncmeta_back_db_init;
+	bi->bi_db_config = config_generic_wrapper;
+	bi->bi_db_open = asyncmeta_back_db_open;
+	bi->bi_db_close = asyncmeta_back_db_close;
+	bi->bi_db_destroy = asyncmeta_back_db_destroy;
+
+	bi->bi_op_bind = asyncmeta_back_bind;
+	bi->bi_op_unbind = 0;
+	bi->bi_op_search = asyncmeta_back_search;
+	bi->bi_op_compare = asyncmeta_back_compare;
+	bi->bi_op_modify = asyncmeta_back_modify;
+	bi->bi_op_modrdn = asyncmeta_back_modrdn;
+	bi->bi_op_add = asyncmeta_back_add;
+	bi->bi_op_delete = asyncmeta_back_delete;
+	bi->bi_op_abandon = 0;
+
+	bi->bi_extended = 0;
+
+	bi->bi_chk_referrals = 0;
+
+	bi->bi_connection_init = 0;
+	bi->bi_connection_destroy =  0 /* asyncmeta_back_conn_destroy */;
+
+	return asyncmeta_back_init_cf( bi );
+}
+
+int
+asyncmeta_back_db_init(
+	Backend		*be,
+	ConfigReply	*cr)
+{
+	a_metainfo_t	*mi;
+	int		i;
+	BackendInfo	*bi;
+
+	bi = backend_info( "ldap" );
+	if ( !bi || !bi->bi_extra ) {
+		Debug( LDAP_DEBUG_ANY,
+			"asyncmeta_back_db_init: needs back-ldap\n" );
+		return 1;
+	}
+
+	mi = ch_calloc( 1, sizeof( a_metainfo_t ) );
+	if ( mi == NULL ) {
+		return -1;
+	}
+
+	/* set default flags */
+	mi->mi_flags =
+		META_BACK_F_DEFER_ROOTDN_BIND
+		| META_BACK_F_PROXYAUTHZ_ALWAYS
+		| META_BACK_F_PROXYAUTHZ_ANON
+		| META_BACK_F_PROXYAUTHZ_NOANON;
+
+	/*
+	 * At present the default is no default target;
+	 * this may change
+	 */
+	mi->mi_defaulttarget = META_DEFAULT_TARGET_NONE;
+	mi->mi_bind_timeout.tv_sec = 0;
+	mi->mi_bind_timeout.tv_usec = META_BIND_TIMEOUT;
+
+	mi->mi_rebind_f = asyncmeta_back_default_rebind;
+	mi->mi_urllist_f = asyncmeta_back_default_urllist;
+
+	ldap_pvt_thread_mutex_init( &mi->mi_cache.mutex );
+
+	/* safe default */
+	mi->mi_nretries = META_RETRY_DEFAULT;
+	mi->mi_version = LDAP_VERSION3;
+
+	for ( i = 0; i < SLAP_OP_LAST; i++ ) {
+		mi->mi_timeout[ i ] = META_BACK_CFG_DEFAULT_OPS_TIMEOUT;
+	}
+
+	for ( i = LDAP_BACK_PCONN_FIRST; i < LDAP_BACK_PCONN_LAST; i++ ) {
+		mi->mi_conn_priv[ i ].mic_num = 0;
+		LDAP_TAILQ_INIT( &mi->mi_conn_priv[ i ].mic_priv );
+	}
+	mi->mi_conn_priv_max = LDAP_BACK_CONN_PRIV_DEFAULT;
+
+	mi->mi_ldap_extra = (ldap_extra_t *)bi->bi_extra;
+	ldap_pvt_thread_mutex_init( &mi->mi_mc_mutex);
+
+	be->be_private = mi;
+	be->be_cf_ocs = be->bd_info->bi_cf_ocs;
+
+	return 0;
+}
+
+int
+asyncmeta_target_finish(
+	a_metainfo_t *mi,
+	a_metatarget_t *mt,
+	const char *log,
+	char *msg,
+	size_t msize
+)
+{
+	slap_bindconf	sb = { BER_BVNULL };
+	int rc;
+
+	ber_str2bv( mt->mt_uri, 0, 0, &sb.sb_uri );
+	sb.sb_version = mt->mt_version;
+	sb.sb_method = LDAP_AUTH_SIMPLE;
+	BER_BVSTR( &sb.sb_binddn, "" );
+
+	if ( META_BACK_TGT_T_F_DISCOVER( mt ) ) {
+		rc = slap_discover_feature( &sb,
+				slap_schema.si_ad_supportedFeatures->ad_cname.bv_val,
+				LDAP_FEATURE_ABSOLUTE_FILTERS );
+		if ( rc == LDAP_COMPARE_TRUE ) {
+			mt->mt_flags |= LDAP_BACK_F_T_F;
+		}
+	}
+
+	if ( META_BACK_TGT_CANCEL_DISCOVER( mt ) ) {
+		rc = slap_discover_feature( &sb,
+				slap_schema.si_ad_supportedExtension->ad_cname.bv_val,
+				LDAP_EXOP_CANCEL );
+		if ( rc == LDAP_COMPARE_TRUE ) {
+			mt->mt_flags |= LDAP_BACK_F_CANCEL_EXOP;
+		}
+	}
+
+	if ( !( mt->mt_idassert_flags & LDAP_BACK_AUTH_OVERRIDE )
+		|| mt->mt_idassert_authz != NULL )
+	{
+		mi->mi_flags &= ~META_BACK_F_PROXYAUTHZ_ALWAYS;
+	}
+
+	if ( ( mt->mt_idassert_flags & LDAP_BACK_AUTH_AUTHZ_ALL )
+		&& !( mt->mt_idassert_flags & LDAP_BACK_AUTH_PRESCRIPTIVE ) )
+	{
+		Debug(LDAP_DEBUG_ANY,
+		      "%s: inconsistent idassert configuration " "(likely authz=\"*\" used with \"non-prescriptive\" flag) (target %s)\n",
+		      log, mt->mt_uri );
+		return 1;
+	}
+
+	if ( !( mt->mt_idassert_flags & LDAP_BACK_AUTH_AUTHZ_ALL ) )
+	{
+		mi->mi_flags &= ~META_BACK_F_PROXYAUTHZ_ANON;
+	}
+
+	if ( ( mt->mt_idassert_flags & LDAP_BACK_AUTH_PRESCRIPTIVE ) )
+	{
+		mi->mi_flags &= ~META_BACK_F_PROXYAUTHZ_NOANON;
+	}
+
+	return 0;
+}
+
+int
+asyncmeta_back_db_open(
+	Backend		*be,
+	ConfigReply	*cr )
+{
+	a_metainfo_t	*mi = (a_metainfo_t *)be->be_private;
+	char msg[SLAP_TEXT_BUFLEN];
+	int		i;
+
+	if ( mi->mi_ntargets == 0 ) {
+		/* Dynamically added, nothing to check here until
+		 * some targets get added
+		 */
+		if ( slapMode & SLAP_SERVER_RUNNING )
+			return 0;
+
+		Debug( LDAP_DEBUG_ANY,
+			"asyncmeta_back_db_open: no targets defined\n" );
+		return 1;
+	}
+	mi->mi_num_conns = 0;
+	for ( i = 0; i < mi->mi_ntargets; i++ ) {
+		a_metatarget_t	*mt = mi->mi_targets[ i ];
+		if ( asyncmeta_target_finish( mi, mt,
+			"asyncmeta_back_db_open", msg, sizeof( msg )))
+			return 1;
+	}
+	mi->mi_num_conns = (mi->mi_max_target_conns == 0) ? META_BACK_CFG_MAX_TARGET_CONNS : mi->mi_max_target_conns;
+	assert(mi->mi_num_conns > 0);
+	mi->mi_conns = ch_calloc( mi->mi_num_conns, sizeof( a_metaconn_t ));
+	for (i = 0; i < mi->mi_num_conns; i++) {
+		a_metaconn_t *mc = &mi->mi_conns[i];
+		ldap_pvt_thread_mutex_init( &mc->mc_om_mutex);
+		mc->mc_authz_target = META_BOUND_NONE;
+		mc->mc_conns = ch_calloc( mi->mi_ntargets, sizeof( a_metasingleconn_t ));
+		mc->mc_info = mi;
+		LDAP_STAILQ_INIT( &mc->mc_om_list );
+	}
+	mi->mi_suffix = be->be_suffix[0];
+	ldap_pvt_thread_mutex_lock( &slapd_rq.rq_mutex );
+	mi->mi_task = ldap_pvt_runqueue_insert( &slapd_rq, 1,
+		asyncmeta_timeout_loop, mi, "asyncmeta_timeout_loop", mi->mi_suffix.bv_val );
+	ldap_pvt_thread_mutex_unlock( &slapd_rq.rq_mutex );
+	return 0;
+}
+
+/*
+ * asyncmeta_back_conn_free()
+ *
+ * actually frees a connection; the reference count must be 0,
+ * and it must not (or no longer) be in the cache.
+ */
+void
+asyncmeta_back_conn_free(
+	void 		*v_mc )
+{
+	a_metaconn_t		*mc = v_mc;
+
+	assert( mc != NULL );
+	ldap_pvt_thread_mutex_destroy( &mc->mc_om_mutex );
+	free( mc );
+}
+
+static void
+asyncmeta_back_stop_miconns( a_metainfo_t *mi )
+{
+
+	/*Todo do any other mc cleanup here if necessary*/
+}
+
+static void
+asyncmeta_back_clear_miconns( a_metainfo_t *mi )
+{
+	int i, j;
+	a_metaconn_t *mc;
+	for (i = 0; i < mi->mi_num_conns; i++) {
+		mc = &mi->mi_conns[i];
+		/* todo clear the message queue */
+		for (j = 0; j < mi->mi_ntargets; j ++) {
+			asyncmeta_clear_one_msc(NULL, mc, j, 1, __FUNCTION__);
+		}
+		free(mc->mc_conns);
+		ldap_pvt_thread_mutex_destroy( &mc->mc_om_mutex );
+	}
+	free(mi->mi_conns);
+}
+
+static void
+asyncmeta_target_free(
+	a_metatarget_t	*mt )
+{
+	if ( mt->mt_uri ) {
+		free( mt->mt_uri );
+		ldap_pvt_thread_mutex_destroy( &mt->mt_uri_mutex );
+	}
+	if ( mt->mt_subtree ) {
+		asyncmeta_subtree_destroy( mt->mt_subtree );
+		mt->mt_subtree = NULL;
+	}
+	if ( mt->mt_filter ) {
+		asyncmeta_filter_destroy( mt->mt_filter );
+		mt->mt_filter = NULL;
+	}
+	if ( !BER_BVISNULL( &mt->mt_psuffix ) ) {
+		free( mt->mt_psuffix.bv_val );
+	}
+	if ( !BER_BVISNULL( &mt->mt_nsuffix ) ) {
+		free( mt->mt_nsuffix.bv_val );
+	}
+	if ( !BER_BVISNULL( &mt->mt_binddn ) ) {
+		free( mt->mt_binddn.bv_val );
+	}
+	if ( !BER_BVISNULL( &mt->mt_bindpw ) ) {
+		free( mt->mt_bindpw.bv_val );
+	}
+	if ( !BER_BVISNULL( &mt->mt_idassert_authcID ) ) {
+		ch_free( mt->mt_idassert_authcID.bv_val );
+	}
+	if ( !BER_BVISNULL( &mt->mt_idassert_authcDN ) ) {
+		ch_free( mt->mt_idassert_authcDN.bv_val );
+	}
+	if ( !BER_BVISNULL( &mt->mt_idassert_passwd ) ) {
+		ch_free( mt->mt_idassert_passwd.bv_val );
+	}
+	if ( !BER_BVISNULL( &mt->mt_idassert_authzID ) ) {
+		ch_free( mt->mt_idassert_authzID.bv_val );
+	}
+	if ( !BER_BVISNULL( &mt->mt_idassert_sasl_mech ) ) {
+		ch_free( mt->mt_idassert_sasl_mech.bv_val );
+	}
+	if ( !BER_BVISNULL( &mt->mt_idassert_sasl_realm ) ) {
+		ch_free( mt->mt_idassert_sasl_realm.bv_val );
+	}
+	if ( mt->mt_idassert_authz != NULL ) {
+		ber_bvarray_free( mt->mt_idassert_authz );
+	}
+	if ( !BER_BVISNULL( &mt->mt_lsuffixm )) {
+		ch_free( mt->mt_lsuffixm.bv_val );
+	}
+	if ( !BER_BVISNULL( &mt->mt_rsuffixm )) {
+		ch_free( mt->mt_rsuffixm.bv_val );
+	}
+	free( mt );
+}
+
+int
+asyncmeta_back_db_close(
+	Backend		*be,
+	ConfigReply	*cr )
+{
+	a_metainfo_t	*mi;
+
+	if ( be->be_private ) {
+		mi = ( a_metainfo_t * )be->be_private;
+		if ( mi->mi_task != NULL ) {
+			ldap_pvt_thread_mutex_lock( &slapd_rq.rq_mutex );
+			if ( ldap_pvt_runqueue_isrunning( &slapd_rq, mi->mi_task )) {
+				ldap_pvt_runqueue_stoptask( &slapd_rq,  mi->mi_task);
+			}
+			ldap_pvt_thread_mutex_unlock( &slapd_rq.rq_mutex );
+			mi->mi_task = NULL;
+		}
+		ldap_pvt_thread_mutex_lock( &mi->mi_mc_mutex );
+		asyncmeta_back_stop_miconns( mi );
+		ldap_pvt_thread_mutex_unlock( &mi->mi_mc_mutex );
+	}
+	return 0;
+}
+
+int
+asyncmeta_back_db_destroy(
+	Backend		*be,
+	ConfigReply	*cr )
+{
+	a_metainfo_t	*mi;
+
+	if ( be->be_private ) {
+		int i;
+
+		mi = ( a_metainfo_t * )be->be_private;
+		/*
+		 * Destroy the per-target stuff (assuming there's at
+		 * least one ...)
+		 */
+		if ( mi->mi_targets != NULL ) {
+			for ( i = 0; i < mi->mi_ntargets; i++ ) {
+				a_metatarget_t	*mt = mi->mi_targets[ i ];
+
+				if ( META_BACK_TGT_QUARANTINE( mt ) ) {
+					if ( mt->mt_quarantine.ri_num != mi->mi_quarantine.ri_num )
+					{
+						mi->mi_ldap_extra->retry_info_destroy( &mt->mt_quarantine );
+					}
+
+					ldap_pvt_thread_mutex_destroy( &mt->mt_quarantine_mutex );
+				}
+
+				asyncmeta_target_free( mt );
+			}
+
+			free( mi->mi_targets );
+		}
+
+		ldap_pvt_thread_mutex_lock( &mi->mi_cache.mutex );
+		if ( mi->mi_cache.tree ) {
+			ldap_avl_free( mi->mi_cache.tree, asyncmeta_dncache_free );
+		}
+
+		ldap_pvt_thread_mutex_unlock( &mi->mi_cache.mutex );
+		ldap_pvt_thread_mutex_destroy( &mi->mi_cache.mutex );
+
+		if ( mi->mi_candidates != NULL ) {
+			ber_memfree_x( mi->mi_candidates, NULL );
+		}
+
+		if ( META_BACK_QUARANTINE( mi ) ) {
+			mi->mi_ldap_extra->retry_info_destroy( &mi->mi_quarantine );
+		}
+
+		ldap_pvt_thread_mutex_lock( &mi->mi_mc_mutex );
+		asyncmeta_back_clear_miconns(mi);
+		ldap_pvt_thread_mutex_unlock( &mi->mi_mc_mutex );
+		ldap_pvt_thread_mutex_destroy( &mi->mi_mc_mutex );
+
+		free( be->be_private );
+	}
+	return 0;
+}
+
+#if SLAPD_ASYNCMETA == SLAPD_MOD_DYNAMIC
+
+/* conditionally define the init_module() function */
+SLAP_BACKEND_INIT_MODULE( asyncmeta )
+
+#endif /* SLAPD_ASYNCMETA == SLAPD_MOD_DYNAMIC */
diff --git a/servers/slapd/back-asyncmeta/map.c b/servers/slapd/back-asyncmeta/map.c
new file mode 100644
index 0000000..b811708
--- /dev/null
+++ b/servers/slapd/back-asyncmeta/map.c
@@ -0,0 +1,214 @@
+/* map.c - ldap backend mapping routines */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016-2022 The OpenLDAP Foundation.
+ * Portions Copyright 2016 Symas Corporation.
+ * 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 developed by Symas Corporation
+ * based on back-meta module for inclusion in OpenLDAP Software.
+ * This work was sponsored by Ericsson. */
+
+/* This is an altered version */
+/*
+ * Copyright 1999, Howard Chu, All rights reserved. <hyc@highlandsun.com>
+ *
+ * Permission is granted to anyone to use this software for any purpose
+ * on any computer system, and to alter it and redistribute it, subject
+ * to the following restrictions:
+ *
+ * 1. The author is not responsible for the consequences of use of this
+ *    software, no matter how awful, even if they arise from flaws in it.
+ *
+ * 2. The origin of this software must not be misrepresented, either by
+ *    explicit claim or by omission.  Since few users ever read sources,
+ *    credits should appear in the documentation.
+ *
+ * 3. Altered versions must be plainly marked as such, and must not be
+ *    misrepresented as being the original software.  Since few users
+ *    ever read sources, credits should appear in the documentation.
+ *
+ * 4. This notice may not be removed or altered.
+ *
+ *
+ *
+ * Copyright 2016, Symas Corporation
+ *
+ * This is based on the back-meta/map.c version by Pierangelo Masarati.
+ * The previously reported conditions apply to the modified code as well.
+ * Changes in the original code are highlighted where required.
+ * Credits for the original code go to the author, Howard Chu.
+ */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/string.h>
+#include <ac/socket.h>
+
+#include "slap.h"
+#include "lutil.h"
+#include "../back-ldap/back-ldap.h"
+#include "back-asyncmeta.h"
+
+void
+asyncmeta_referral_result_rewrite(
+	a_dncookie		*dc,
+	BerVarray		a_vals
+)
+{
+	int		i, last;
+
+	assert( dc != NULL );
+	assert( a_vals != NULL );
+
+	for ( last = 0; !BER_BVISNULL( &a_vals[ last ] ); last++ )
+		;
+	last--;
+
+	for ( i = 0; !BER_BVISNULL( &a_vals[ i ] ); i++ ) {
+		struct berval	dn,
+				olddn = BER_BVNULL;
+		int		rc;
+		LDAPURLDesc	*ludp;
+
+		rc = ldap_url_parse( a_vals[ i ].bv_val, &ludp );
+		if ( rc != LDAP_URL_SUCCESS ) {
+			/* leave attr untouched if massage failed */
+			continue;
+		}
+
+		/* FIXME: URLs like "ldap:///dc=suffix" if passed
+		 * thru ldap_url_parse() and ldap_url_desc2str()
+		 * get rewritten as "ldap:///dc=suffix??base";
+		 * we don't want this to occur... */
+		if ( ludp->lud_scope == LDAP_SCOPE_BASE ) {
+			ludp->lud_scope = LDAP_SCOPE_DEFAULT;
+		}
+
+		ber_str2bv( ludp->lud_dn, 0, 0, &olddn );
+
+		asyncmeta_dn_massage( dc, &olddn, &dn );
+		/* leave attr untouched if massage did nothing */
+		if ( olddn.bv_val != dn.bv_val )
+		{
+			char	*newurl;
+
+			ludp->lud_dn = dn.bv_val;
+			newurl = ldap_url_desc2str( ludp );
+			dc->op->o_tmpfree( dn.bv_val, dc->memctx );
+			if ( newurl )
+			{
+				/* FIXME: leave attr untouched
+				 * even if ldap_url_desc2str failed...
+				 */
+
+				ber_memfree_x( a_vals[ i ].bv_val, dc->op->o_tmpmemctx );
+				ber_str2bv_x( newurl, 0, 1, &a_vals[ i ], dc->memctx );
+				ber_memfree( newurl );
+				ludp->lud_dn = olddn.bv_val;
+			}
+		}
+		ldap_free_urldesc( ludp );
+	}
+}
+
+void
+asyncmeta_dnattr_result_rewrite(
+	a_dncookie		*dc,
+	BerVarray		a_vals
+)
+{
+	struct berval	bv;
+	int		i;
+
+	assert( a_vals != NULL );
+
+	for ( i = 0; !BER_BVISNULL( &a_vals[i] ); i++ ) {
+		asyncmeta_dn_massage( dc, &a_vals[i], &bv );
+		if ( bv.bv_val != a_vals[i].bv_val ) {
+			ber_memfree_x( a_vals[i].bv_val, dc->memctx );
+			a_vals[i] = bv;
+		}
+	}
+}
+
+/*
+ * asyncmeta_dn_massage
+ *
+ * Aliases the suffix.
+ */
+void
+asyncmeta_dn_massage(
+	a_dncookie *dc,
+	struct berval *odn,
+	struct berval *res
+)
+{
+	struct berval pretty = {0,NULL}, *dn = odn;
+	struct berval *osuff, *nsuff;
+	int diff;
+
+	assert( res );
+
+	BER_BVZERO(res);
+	if ( dn == NULL )
+		return;
+
+	/* no suffix massage configured */
+	if ( !dc->target->mt_lsuffixm.bv_val ) {
+		*res = *dn;
+		return;
+	}
+
+	if ( dc->to_from == MASSAGE_REQ ) {
+		osuff = &dc->target->mt_lsuffixm;
+		nsuff = &dc->target->mt_rsuffixm;
+	} else {
+		osuff = &dc->target->mt_rsuffixm;
+		nsuff = &dc->target->mt_lsuffixm;
+		/* DN from remote server may be in arbitrary form.
+		 * Pretty it so we can parse reliably.
+		 */
+		dnPretty( NULL, dn, &pretty, dc->op->o_tmpmemctx );
+		if (pretty.bv_val) dn = &pretty;
+	}
+
+	diff = dn->bv_len - osuff->bv_len;
+	/* DN is shorter than suffix - ignore */
+	if ( diff < 0 ) {
+ignore:
+		*res = *odn;
+		if (pretty.bv_val)
+			dc->op->o_tmpfree( pretty.bv_val, dc->op->o_tmpmemctx );
+		return;
+	}
+
+	/* DN longer than our suffix and doesn't match */
+	if ( diff > 0 && !DN_SEPARATOR(dn->bv_val[diff-1]))
+		goto ignore;
+
+	/* suffix is same length as ours, but doesn't match */
+	if ( strcasecmp( osuff->bv_val, &dn->bv_val[diff] ))
+		goto ignore;
+
+	res->bv_len = diff + nsuff->bv_len;
+	res->bv_val = dc->op->o_tmpalloc( res->bv_len + 1, dc->memctx );
+	strncpy( res->bv_val, dn->bv_val, diff );
+	strcpy( &res->bv_val[diff], nsuff->bv_val );
+
+	if (pretty.bv_val)
+		dc->op->o_tmpfree( pretty.bv_val, dc->op->o_tmpmemctx );
+}
diff --git a/servers/slapd/back-asyncmeta/message_queue.c b/servers/slapd/back-asyncmeta/message_queue.c
new file mode 100644
index 0000000..f2e9c86
--- /dev/null
+++ b/servers/slapd/back-asyncmeta/message_queue.c
@@ -0,0 +1,236 @@
+/* message_queue.c - routines to maintain the per-connection lists
+ * of pending operations */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016-2022 The OpenLDAP Foundation.
+ * Portions Copyright 2016 Symas Corporation.
+ * 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 developed by Symas Corporation
+ * based on back-meta module for inclusion in OpenLDAP Software.
+ * This work was sponsored by Ericsson. */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/socket.h>
+#include <ac/string.h>
+#include <ac/time.h>
+
+#include "lutil.h"
+#include "slap.h"
+#include "../back-ldap/back-ldap.h"
+#include "back-asyncmeta.h"
+#include "../../../libraries/liblber/lber-int.h"
+#include "lutil.h"
+
+
+typedef struct listptr {
+	void *reserved;
+	struct listptr *next;
+} listptr;
+
+typedef struct listhead {
+	struct listptr *list;
+	int cnt;
+} listhead;
+
+#ifndef LH_MAX
+#define LH_MAX	16
+#endif
+
+static void asyncmeta_memctx_put(void *threadctx, void *memctx)
+{
+	slap_sl_mem_setctx(threadctx, NULL);
+	slap_sl_mem_destroy((void *)1, memctx);
+}
+
+int asyncmeta_new_bm_context(Operation *op,
+			     SlapReply *rs,
+			     bm_context_t **new_bc,
+			     int ntargets,
+			     a_metainfo_t	*mi)
+{
+	int i;
+	*new_bc = op->o_tmpcalloc( 1, sizeof( bm_context_t ), op->o_tmpmemctx );
+
+	(*new_bc)->op = op;
+	(*new_bc)->copy_op = *op;
+	(*new_bc)->candidates = op->o_tmpcalloc(ntargets, sizeof(SlapReply),op->o_tmpmemctx);
+	(*new_bc)->msgids = op->o_tmpcalloc(ntargets, sizeof(int),op->o_tmpmemctx);
+	(*new_bc)->nretries = op->o_tmpcalloc(ntargets, sizeof(int),op->o_tmpmemctx);
+	(*new_bc)->c_peer_name = op->o_conn->c_peer_name;
+	(*new_bc)->is_root = be_isroot( op );
+
+	switch(op->o_tag) {
+	case LDAP_REQ_COMPARE:
+		{
+		AttributeAssertion *ava = op->o_tmpcalloc( 1, sizeof(AttributeAssertion), op->o_tmpmemctx );
+		*ava = *op->orc_ava;
+		op->orc_ava = ava;
+		}
+		break;
+	case LDAP_REQ_MODRDN:
+		if (op->orr_newSup != NULL) {
+			struct berval *bv = op->o_tmpalloc( sizeof( struct berval ), op->o_tmpmemctx );
+			*bv = *op->orr_newSup;
+			op->orr_newSup = bv;
+		}
+
+		if (op->orr_nnewSup != NULL) {
+			struct berval *bv = op->o_tmpalloc( sizeof( struct berval ), op->o_tmpmemctx );
+			*bv = *op->orr_nnewSup;
+			op->orr_nnewSup = bv;
+		}
+		break;
+	default:
+		break;
+	}
+	for (i = 0; i < ntargets; i++) {
+		(*new_bc)->msgids[i] = META_MSGID_UNDEFINED;
+	}
+	for (i = 0; i < ntargets; i++) {
+		(*new_bc)->nretries[i] = mi->mi_targets[i]->mt_nretries;
+	}
+	return LDAP_SUCCESS;
+}
+
+void asyncmeta_free_op(Operation *op)
+{
+	assert (op != NULL);
+	switch (op->o_tag) {
+	case LDAP_REQ_SEARCH:
+		break;
+	case LDAP_REQ_ADD:
+		if ( op->ora_modlist != NULL ) {
+			slap_mods_free(op->ora_modlist, 0 );
+		}
+
+		if ( op->ora_e != NULL ) {
+			entry_free( op->ora_e );
+		}
+
+		break;
+	case LDAP_REQ_MODIFY:
+		if ( op->orm_modlist != NULL ) {
+			slap_mods_free(op->orm_modlist, 1 );
+		}
+		break;
+	case LDAP_REQ_MODRDN:
+		if ( op->orr_modlist != NULL ) {
+			slap_mods_free(op->orr_modlist, 1 );
+		}
+		break;
+	case LDAP_REQ_COMPARE:
+		break;
+	case LDAP_REQ_DELETE:
+		break;
+	default:
+		Debug( LDAP_DEBUG_TRACE, "==> asyncmeta_free_op : other message type" );
+	}
+
+	connection_op_finish( op );
+	slap_op_free( op, op->o_threadctx );
+}
+
+
+
+
+void asyncmeta_clear_bm_context(bm_context_t *bc)
+{
+
+	Operation *op = bc->op;
+	void *thrctx, *memctx;
+	int i;
+
+	if ( bc->bc_mc && bc->bc_mc->mc_info ) {
+		for (i = 0; i < bc->bc_mc->mc_info->mi_ntargets; i++) {
+			if (bc->candidates[ i ].sr_text != NULL) {
+				ch_free( (char *)bc->candidates[ i ].sr_text );
+				bc->candidates[ i ].sr_text = NULL;
+			}
+		}
+	}
+
+	if (op->o_conn->c_conn_idx == -1)
+		return;
+	memctx = op->o_tmpmemctx;
+	thrctx = op->o_threadctx;
+	while (op->o_bd == bc->copy_op.o_bd)
+		ldap_pvt_thread_yield();
+	asyncmeta_free_op(op);
+	asyncmeta_memctx_put(thrctx, memctx);
+}
+
+int asyncmeta_add_message_queue(a_metaconn_t *mc, bm_context_t *bc)
+{
+	a_metainfo_t *mi = mc->mc_info;
+	int max_pending_ops = (mi->mi_max_pending_ops == 0) ? META_BACK_CFG_MAX_PENDING_OPS : mi->mi_max_pending_ops;
+
+	Debug( LDAP_DEBUG_TRACE, "add_message_queue: mc %p, pending_ops %d, max_pending %d\n",
+		mc, mc->pending_ops, max_pending_ops );
+
+	assert(bc->bc_mc == NULL);
+	if (mc->pending_ops >= max_pending_ops) {
+		return LDAP_BUSY;
+	}
+	bc->bc_mc = mc;
+
+	slap_sl_mem_setctx(bc->op->o_threadctx, NULL);
+	LDAP_STAILQ_INSERT_TAIL( &mc->mc_om_list, bc, bc_next);
+	mc->pending_ops++;
+	return LDAP_SUCCESS;
+}
+
+
+void
+asyncmeta_drop_bc(a_metaconn_t *mc, bm_context_t *bc)
+{
+	bm_context_t *om;
+	LDAP_STAILQ_FOREACH( om, &mc->mc_om_list, bc_next ) {
+		if (om == bc) {
+			LDAP_STAILQ_REMOVE(&mc->mc_om_list, om, bm_context_t, bc_next);
+			mc->pending_ops--;
+			break;
+		}
+	}
+	assert(om == bc);
+	assert(bc->bc_mc == mc);
+}
+
+
+bm_context_t *
+asyncmeta_find_message(ber_int_t msgid, a_metaconn_t *mc, int candidate)
+{
+	bm_context_t *om;
+	LDAP_STAILQ_FOREACH( om, &mc->mc_om_list, bc_next ) {
+		if (om->candidates[candidate].sr_msgid == msgid && !om->bc_invalid) {
+			break;
+		}
+	}
+	return om;
+}
+
+bm_context_t *
+asyncmeta_bc_in_queue(a_metaconn_t *mc, bm_context_t *bc)
+{
+	bm_context_t *om;
+	LDAP_STAILQ_FOREACH( om, &mc->mc_om_list, bc_next ) {
+		if (om == bc) {
+			return bc;
+		}
+	}
+	return NULL;
+}
diff --git a/servers/slapd/back-asyncmeta/meta_result.c b/servers/slapd/back-asyncmeta/meta_result.c
new file mode 100644
index 0000000..0ce279a
--- /dev/null
+++ b/servers/slapd/back-asyncmeta/meta_result.c
@@ -0,0 +1,1825 @@
+/* meta_result.c - target responses processing */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016-2022 The OpenLDAP Foundation.
+ * Portions Copyright 2016 Symas Corporation.
+ * 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 developed by Symas Corporation
+ * based on back-meta module for inclusion in OpenLDAP Software.
+ * This work was sponsored by Ericsson. */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/string.h>
+#include <ac/socket.h>
+
+#include "slap.h"
+#include "../back-ldap/back-ldap.h"
+#include "back-asyncmeta.h"
+#include "ldap_rq.h"
+#include "../../../libraries/liblber/lber-int.h"
+
+static void
+asyncmeta_send_ldap_result(bm_context_t *bc, Operation *op, SlapReply *rs)
+{
+	if (bc->c_peer_name.bv_val == op->o_conn->c_peer_name.bv_val && !bc->op->o_abandon ) {
+		send_ldap_result(&bc->copy_op, rs);
+		bc->op->o_callback = bc->copy_op.o_callback;
+		bc->op->o_extra = bc->copy_op.o_extra;
+		bc->op->o_ctrls = bc->copy_op.o_ctrls;
+	}
+}
+
+static int
+asyncmeta_is_last_result(a_metaconn_t *mc, bm_context_t *bc, int candidate)
+{
+	a_metainfo_t	*mi = mc->mc_info;
+	int i;
+	SlapReply *candidates = bc->candidates;
+	for ( i = 0; i < mi->mi_ntargets; i++ ) {
+		if ( !META_IS_CANDIDATE( &candidates[ i ] ) ) {
+			continue;
+		}
+		if (candidates[ i ].sr_msgid != META_MSGID_IGNORE ||
+		    candidates[ i ].sr_type != REP_RESULT) {
+			return 1;
+		}
+	}
+	return 0;
+}
+
+meta_search_candidate_t
+asyncmeta_dobind_result(
+	a_metaconn_t		*mc,
+	int			candidate,
+	SlapReply		*bind_result,
+	LDAPMessage		*res )
+{
+	a_metainfo_t		*mi = mc->mc_info;
+	a_metatarget_t		*mt = mi->mi_targets[ candidate ];
+	a_metasingleconn_t	*msc = &mc->mc_conns[ candidate ];
+
+	meta_search_candidate_t	retcode = META_SEARCH_NOT_CANDIDATE;
+	int			rc;
+
+	assert( msc->msc_ldr != NULL );
+
+	if ( mi->mi_idle_timeout != 0 ) {
+		asyncmeta_set_msc_time(msc);
+	}
+
+	if ( LogTest( asyncmeta_debug ) ) {
+		char	time_buf[ SLAP_TEXT_BUFLEN ];
+		asyncmeta_get_timestamp(time_buf);
+		Debug( asyncmeta_debug, "[%x] [%s] asyncmeta_dobind_result msc: %p, "
+		       "msc->msc_binding_time: %x, msc->msc_flags:%x\n ",
+		       (unsigned int)slap_get_time(), time_buf, msc,
+		       (unsigned int)msc->msc_binding_time, msc->msc_mscflags );
+	}
+	/* FIXME: matched? referrals? response controls? */
+	rc = ldap_parse_result( msc->msc_ldr, res,
+				&(bind_result->sr_err),
+				(char **)&(bind_result->sr_matched),
+				(char **)&(bind_result->sr_text),
+				NULL, NULL, 0 );
+
+	if ( LogTest( asyncmeta_debug ) ) {
+		char	time_buf[ SLAP_TEXT_BUFLEN ];
+		asyncmeta_get_timestamp(time_buf);
+		Debug( asyncmeta_debug,
+		       "[%s] asyncmeta_dobind_result error=%d msc: %p\n",
+		       time_buf,bind_result->sr_err, msc );
+	}
+
+	if ( rc != LDAP_SUCCESS ) {
+		bind_result->sr_err = rc;
+	}
+	rc = slap_map_api2result( bind_result );
+
+	LDAP_BACK_CONN_BINDING_CLEAR( msc );
+	if ( rc != LDAP_SUCCESS ) {
+		bind_result->sr_err = rc;
+	} else {
+		/* FIXME: check if bound as idassert authcDN! */
+		if ( BER_BVISNULL( &msc->msc_bound_ndn )
+			|| BER_BVISEMPTY( &msc->msc_bound_ndn ) )
+		{
+			LDAP_BACK_CONN_ISANON_SET( msc );
+			if ( LogTest( asyncmeta_debug ) ) {
+				char	time_buf[ SLAP_TEXT_BUFLEN ];
+				asyncmeta_get_timestamp(time_buf);
+				Debug( asyncmeta_debug, "[%s] asyncmeta_dobind_result anonymous msc: %p\n",
+				      time_buf, msc );
+			}
+
+		} else {
+			if ( META_BACK_TGT_SAVECRED( mt ) &&
+				!BER_BVISNULL( &msc->msc_cred ) &&
+				!BER_BVISEMPTY( &msc->msc_cred ) )
+			{
+				ldap_set_rebind_proc( msc->msc_ldr, mt->mt_rebind_f, msc );
+			}
+			if ( LogTest( asyncmeta_debug ) ) {
+				char	time_buf[ SLAP_TEXT_BUFLEN ];
+				asyncmeta_get_timestamp(time_buf);
+				Debug( asyncmeta_debug, "[%s] asyncmeta_dobind_result success msc: %p\n",
+				      time_buf, msc );
+			}
+			LDAP_BACK_CONN_ISBOUND_SET( msc );
+		}
+		retcode = META_SEARCH_CANDIDATE;
+	}
+	return retcode;
+}
+
+static int
+asyncmeta_send_entry(
+	Operation 	*op,
+	SlapReply	*rs,
+	a_metaconn_t	*mc,
+	int 		target,
+	LDAPMessage 	*e )
+{
+	a_metainfo_t 		*mi = mc->mc_info;
+	struct berval		a, mapped = BER_BVNULL;
+	int			check_sorted_attrs = 0;
+	Entry 			ent = {0};
+	BerElement 		ber = *ldap_get_message_ber( e );
+	Attribute 		*attr, **attrp;
+	struct berval 		bdn,
+				dn = BER_BVNULL;
+	const char 		*text;
+	a_dncookie		dc;
+	ber_len_t		len;
+	int			rc;
+	void	*mem_mark;
+
+	mem_mark = slap_sl_mark( op->o_tmpmemctx );
+	ber_set_option( &ber, LBER_OPT_BER_MEMCTX, &op->o_tmpmemctx );
+
+	if ( ber_scanf( &ber, "l{", &len ) == LBER_ERROR ) {
+		return LDAP_DECODING_ERROR;
+	}
+
+	if ( ber_set_option( &ber, LBER_OPT_REMAINING_BYTES, &len ) != LBER_OPT_SUCCESS ) {
+		return LDAP_OTHER;
+	}
+
+	if ( ber_scanf( &ber, "m{", &bdn ) == LBER_ERROR ) {
+		return LDAP_DECODING_ERROR;
+	}
+
+	/*
+	 * Rewrite the dn of the result, if needed
+	 */
+	dc.op = op;
+	dc.target = mi->mi_targets[ target ];
+	dc.memctx = op->o_tmpmemctx;
+	dc.to_from = MASSAGE_REP;
+	asyncmeta_dn_massage( &dc, &bdn, &dn );
+
+	/*
+	 * Note: this may fail if the target host(s) schema differs
+	 * from the one known to the meta, and a DN with unknown
+	 * attributes is returned.
+	 *
+	 * FIXME: should we log anything, or delegate to dnNormalize?
+	 */
+	rc = dnPrettyNormal( NULL, &dn, &ent.e_name, &ent.e_nname,
+		op->o_tmpmemctx );
+	if ( dn.bv_val != bdn.bv_val ) {
+			op->o_tmpfree( dn.bv_val, op->o_tmpmemctx );
+	}
+	BER_BVZERO( &dn );
+
+	if ( rc != LDAP_SUCCESS ) {
+		Debug( LDAP_DEBUG_ANY,
+			"%s asyncmeta_send_entry(\"%s\"): "
+			"invalid DN syntax\n",
+			op->o_log_prefix, ent.e_name.bv_val );
+		rc = LDAP_INVALID_DN_SYNTAX;
+		goto done;
+	}
+
+	/*
+	 * cache dn
+	 */
+	if ( mi->mi_cache.ttl != META_DNCACHE_DISABLED ) {
+		( void )asyncmeta_dncache_update_entry( &mi->mi_cache,
+				&ent.e_nname, target );
+	}
+
+	attrp = &ent.e_attrs;
+
+	while ( ber_scanf( &ber, "{m", &a ) != LBER_ERROR ) {
+		int				last = 0;
+		slap_syntax_validate_func	*validate;
+		slap_syntax_transform_func	*pretty;
+
+		if ( ber_pvt_ber_remaining( &ber ) < 0 ) {
+			Debug( LDAP_DEBUG_ANY,
+				"%s asyncmeta_send_entry(\"%s\"): "
+				"unable to parse attr \"%s\".\n",
+				op->o_log_prefix, ent.e_name.bv_val, a.bv_val );
+
+			rc = LDAP_OTHER;
+			goto done;
+		}
+
+		if ( ber_pvt_ber_remaining( &ber ) == 0 ) {
+			break;
+		}
+
+		attr = op->o_tmpcalloc( 1, sizeof(Attribute), op->o_tmpmemctx );
+		if ( slap_bv2ad( &a, &attr->a_desc, &text )
+				!= LDAP_SUCCESS) {
+			if ( slap_bv2undef_ad( &a, &attr->a_desc, &text,
+				SLAP_AD_PROXIED ) != LDAP_SUCCESS )
+			{
+				Debug(LDAP_DEBUG_ANY,
+				      "%s meta_send_entry(\"%s\"): " "slap_bv2undef_ad(%s): %s\n",
+				      op->o_log_prefix, ent.e_name.bv_val,
+				      mapped.bv_val, text );
+				( void )ber_scanf( &ber, "x" /* [W] */ );
+				op->o_tmpfree( attr, op->o_tmpmemctx );
+				continue;
+			}
+		}
+
+		if ( attr->a_desc->ad_type->sat_flags & SLAP_AT_SORTED_VAL )
+			check_sorted_attrs = 1;
+
+		/* no subschemaSubentry */
+		if ( attr->a_desc == slap_schema.si_ad_subschemaSubentry
+			|| attr->a_desc == slap_schema.si_ad_entryDN )
+		{
+
+			/*
+			 * We eat target's subschemaSubentry because
+			 * a search for this value is likely not
+			 * to resolve to the appropriate backend;
+			 * later, the local subschemaSubentry is
+			 * added.
+			 *
+			 * We also eat entryDN because the frontend
+			 * will reattach it without checking if already
+			 * present...
+			 */
+			( void )ber_scanf( &ber, "x" /* [W] */ );
+			op->o_tmpfree( attr, op->o_tmpmemctx );
+			continue;
+		}
+
+		if ( ber_scanf( &ber, "[W]", &attr->a_vals ) == LBER_ERROR
+				|| attr->a_vals == NULL )
+		{
+			attr->a_vals = (struct berval *)&slap_dummy_bv;
+
+		} else {
+			for ( last = 0; !BER_BVISNULL( &attr->a_vals[ last ] ); ++last )
+				;
+		}
+		attr->a_numvals = last;
+
+		validate = attr->a_desc->ad_type->sat_syntax->ssyn_validate;
+		pretty = attr->a_desc->ad_type->sat_syntax->ssyn_pretty;
+
+		if ( !validate && !pretty ) {
+			ber_bvarray_free_x( attr->a_vals, op->o_tmpmemctx );
+			op->o_tmpfree( attr, op->o_tmpmemctx );
+			goto next_attr;
+		}
+
+		/*
+		 * It is necessary to try to rewrite attributes with
+		 * dn syntax because they might be used in ACLs as
+		 * members of groups; since ACLs are applied to the
+		 * rewritten stuff, no dn-based subecj clause could
+		 * be used at the ldap backend side (see
+		 * http://www.OpenLDAP.org/faq/data/cache/452.html)
+		 * The problem can be overcome by moving the dn-based
+		 * ACLs to the target directory server, and letting
+		 * everything pass thru the ldap backend.
+		 */
+		{
+			int	i;
+
+			if ( attr->a_desc->ad_type->sat_syntax ==
+				slap_schema.si_syn_distinguishedName )
+			{
+				asyncmeta_dnattr_result_rewrite( &dc, attr->a_vals );
+
+			} else if ( attr->a_desc == slap_schema.si_ad_ref ) {
+				asyncmeta_referral_result_rewrite( &dc, attr->a_vals );
+
+			}
+
+			for ( i = 0; i < last; i++ ) {
+				struct berval	pval;
+				int		rc;
+
+				if ( pretty ) {
+					rc = ordered_value_pretty( attr->a_desc,
+						&attr->a_vals[i], &pval, op->o_tmpmemctx );
+
+				} else {
+					rc = ordered_value_validate( attr->a_desc,
+						&attr->a_vals[i], 0 );
+				}
+
+				if ( rc ) {
+					ber_memfree_x( attr->a_vals[i].bv_val, op->o_tmpmemctx );
+					if ( --last == i ) {
+						BER_BVZERO( &attr->a_vals[ i ] );
+						break;
+					}
+					attr->a_vals[i] = attr->a_vals[last];
+					BER_BVZERO( &attr->a_vals[last] );
+					i--;
+					continue;
+				}
+
+				if ( pretty ) {
+					ber_memfree_x( attr->a_vals[i].bv_val, op->o_tmpmemctx );
+					attr->a_vals[i] = pval;
+				}
+			}
+
+			if ( last == 0 && attr->a_vals != &slap_dummy_bv ) {
+				ber_bvarray_free_x( attr->a_vals, op->o_tmpmemctx );
+				op->o_tmpfree( attr, op->o_tmpmemctx );
+				goto next_attr;
+			}
+		}
+
+		if ( last && attr->a_desc->ad_type->sat_equality &&
+			attr->a_desc->ad_type->sat_equality->smr_normalize )
+		{
+			int i;
+
+			attr->a_nvals = op->o_tmpalloc( ( last + 1 ) * sizeof( struct berval ), op->o_tmpmemctx );
+			for ( i = 0; i<last; i++ ) {
+				/* if normalizer fails, drop this value */
+				if ( ordered_value_normalize(
+					SLAP_MR_VALUE_OF_ATTRIBUTE_SYNTAX,
+					attr->a_desc,
+					attr->a_desc->ad_type->sat_equality,
+					&attr->a_vals[i], &attr->a_nvals[i],
+					op->o_tmpmemctx )) {
+					ber_memfree_x( attr->a_vals[i].bv_val, op->o_tmpmemctx );
+					if ( --last == i ) {
+						BER_BVZERO( &attr->a_vals[ i ] );
+						break;
+					}
+					attr->a_vals[i] = attr->a_vals[last];
+					BER_BVZERO( &attr->a_vals[last] );
+					i--;
+				}
+			}
+			BER_BVZERO( &attr->a_nvals[i] );
+			if ( last == 0 ) {
+				ber_bvarray_free_x( attr->a_vals, op->o_tmpmemctx );
+				ber_bvarray_free_x( attr->a_nvals, op->o_tmpmemctx );
+				op->o_tmpfree( attr, op->o_tmpmemctx );
+				goto next_attr;
+			}
+
+		} else {
+			attr->a_nvals = attr->a_vals;
+		}
+
+		attr->a_numvals = last;
+		*attrp = attr;
+		attrp = &attr->a_next;
+next_attr:;
+	}
+
+	/* Check for sorted attributes */
+	if ( check_sorted_attrs ) {
+		for ( attr = ent.e_attrs; attr; attr = attr->a_next ) {
+			if ( attr->a_desc->ad_type->sat_flags & SLAP_AT_SORTED_VAL ) {
+				while ( attr->a_numvals > 1 ) {
+					int i;
+					int rc = slap_sort_vals( (Modifications *)attr, &text, &i, op->o_tmpmemctx );
+					if ( rc != LDAP_TYPE_OR_VALUE_EXISTS )
+						break;
+
+					/* Strip duplicate values */
+					if ( attr->a_nvals != attr->a_vals )
+						ber_memfree_x( attr->a_nvals[i].bv_val, op->o_tmpmemctx );
+					ber_memfree_x( attr->a_vals[i].bv_val, op->o_tmpmemctx );
+					attr->a_numvals--;
+					if ( (unsigned)i < attr->a_numvals ) {
+						attr->a_vals[i] = attr->a_vals[attr->a_numvals];
+						if ( attr->a_nvals != attr->a_vals )
+							attr->a_nvals[i] = attr->a_nvals[attr->a_numvals];
+					}
+					BER_BVZERO(&attr->a_vals[attr->a_numvals]);
+					if ( attr->a_nvals != attr->a_vals )
+						BER_BVZERO(&attr->a_nvals[attr->a_numvals]);
+				}
+				attr->a_flags |= SLAP_ATTR_SORTED_VALS;
+			}
+		}
+	}
+	Debug( LDAP_DEBUG_TRACE,
+	       "%s asyncmeta_send_entry(\"%s\"): "
+	       ".\n",
+	       op->o_log_prefix, ent.e_name.bv_val );
+	ldap_get_entry_controls( mc->mc_conns[target].msc_ldr,
+		e, &rs->sr_ctrls );
+	rs->sr_entry = &ent;
+	rs->sr_attrs = op->ors_attrs;
+	rs->sr_operational_attrs = NULL;
+	rs->sr_flags = mi->mi_targets[ target ]->mt_rep_flags;
+	rs->sr_err = LDAP_SUCCESS;
+	rc = send_search_entry( op, rs );
+	switch ( rc ) {
+	case LDAP_UNAVAILABLE:
+		rc = LDAP_OTHER;
+		break;
+	}
+
+done:;
+	if ( rs->sr_ctrls != NULL ) {
+		ldap_controls_free( rs->sr_ctrls );
+		rs->sr_ctrls = NULL;
+	}
+#if 0
+	while ( ent.e_attrs ) {
+		attr = ent.e_attrs;
+		ent.e_attrs = attr->a_next;
+		if ( attr->a_nvals != attr->a_vals )
+			ber_bvarray_free_x( attr->a_nvals, op->o_tmpmemctx );
+		ber_bvarray_free_x( attr->a_vals, op->o_tmpmemctx );
+		op->o_tmpfree( attr, op->o_tmpmemctx );
+	}
+	if (ent.e_name.bv_val != NULL) {
+		op->o_tmpfree( ent.e_name.bv_val, op->o_tmpmemctx );
+	}
+
+	if (ent.e_nname.bv_val != NULL) {
+		op->o_tmpfree( ent.e_nname.bv_val, op->o_tmpmemctx );
+	}
+	if (rs->sr_entry && rs->sr_entry != &ent) {
+		entry_free( rs->sr_entry );
+	}
+#endif
+	slap_sl_release( mem_mark, op->o_tmpmemctx );
+	rs->sr_entry = NULL;
+	rs->sr_attrs = NULL;
+	return rc;
+}
+
+static void
+asyncmeta_search_last_result(a_metaconn_t *mc, bm_context_t *bc, int candidate, int sres)
+{
+	a_metainfo_t	*mi = mc->mc_info;
+	Operation *op = bc->op;
+	SlapReply *rs = &bc->rs;
+	int	   i;
+	SlapReply *candidates = bc->candidates;
+	char *matched = NULL;
+
+	if ( bc->candidate_match > 0 ) {
+		struct berval	pmatched = BER_BVNULL;
+
+		/* we use the first one */
+		for ( i = 0; i < mi->mi_ntargets; i++ ) {
+			if ( META_IS_CANDIDATE( &candidates[ i ] )
+					&& candidates[ i ].sr_matched != NULL )
+			{
+				struct berval	bv, pbv;
+				int		rc;
+
+				/* if we got success, and this target
+				 * returned noSuchObject, and its suffix
+				 * is a superior of the searchBase,
+				 * ignore the matchedDN */
+				if ( sres == LDAP_SUCCESS
+					&& candidates[ i ].sr_err == LDAP_NO_SUCH_OBJECT
+					&& op->o_req_ndn.bv_len > mi->mi_targets[ i ]->mt_nsuffix.bv_len )
+				{
+					free( (char *)candidates[ i ].sr_matched );
+					candidates[ i ].sr_matched = NULL;
+					continue;
+				}
+
+				ber_str2bv( candidates[ i ].sr_matched, 0, 0, &bv );
+				rc = dnPretty( NULL, &bv, &pbv, op->o_tmpmemctx );
+
+				if ( rc == LDAP_SUCCESS ) {
+
+					/* NOTE: if they all are superiors
+					 * of the baseDN, the shorter is also
+					 * superior of the longer... */
+					if ( pbv.bv_len > pmatched.bv_len ) {
+						if ( !BER_BVISNULL( &pmatched ) ) {
+							op->o_tmpfree( pmatched.bv_val, op->o_tmpmemctx );
+						}
+						pmatched = pbv;
+
+					} else {
+						op->o_tmpfree( pbv.bv_val, op->o_tmpmemctx );
+					}
+				}
+
+				if ( candidates[ i ].sr_matched != NULL ) {
+					free( (char *)candidates[ i ].sr_matched );
+					candidates[ i ].sr_matched = NULL;
+				}
+			}
+		}
+
+		if ( !BER_BVISNULL( &pmatched ) ) {
+			matched = pmatched.bv_val;
+		}
+
+	} else if ( sres == LDAP_NO_SUCH_OBJECT ) {
+		matched = mi->mi_suffix.bv_val;
+	}
+
+	/*
+	 * In case we returned at least one entry, we return LDAP_SUCCESS
+	 * otherwise, the latter error code we got
+	 */
+
+	if ( sres == LDAP_SUCCESS ) {
+		if ( rs->sr_v2ref ) {
+			sres = LDAP_REFERRAL;
+		}
+
+		if ( META_BACK_ONERR_REPORT( mi ) ) {
+			/*
+			 * Report errors, if any
+			 *
+			 * FIXME: we should handle error codes and return the more
+			 * important/reasonable
+			 */
+			for ( i = 0; i < mi->mi_ntargets; i++ ) {
+				if ( !META_IS_CANDIDATE( &candidates[ i ] ) ) {
+					continue;
+				}
+
+				if ( candidates[ i ].sr_err != LDAP_SUCCESS
+					&& candidates[ i ].sr_err != LDAP_NO_SUCH_OBJECT )
+				{
+					sres = candidates[ i ].sr_err;
+					break;
+				}
+			}
+		}
+	}
+	Debug( LDAP_DEBUG_TRACE,
+	       "%s asyncmeta_search_last_result(\"%d\"): "
+	       ".\n",
+	       op->o_log_prefix, candidate );
+	rs->sr_err = sres;
+	rs->sr_matched = ( sres == LDAP_SUCCESS ? NULL : matched );
+	rs->sr_text =  ( sres == LDAP_SUCCESS ? NULL : candidates[candidate].sr_text );
+	rs->sr_ref = ( sres == LDAP_REFERRAL ? rs->sr_v2ref : NULL );
+	asyncmeta_send_ldap_result(bc, op, rs);
+	rs->sr_text = NULL;
+	rs->sr_matched = NULL;
+	rs->sr_ref = NULL;
+}
+
+static meta_search_candidate_t
+asyncmeta_send_pending_op(bm_context_t *bc, int candidate)
+{
+	meta_search_candidate_t	retcode;
+	switch (bc->op->o_tag) {
+		case LDAP_REQ_SEARCH:
+			retcode = asyncmeta_back_search_start( &bc->copy_op, &bc->rs, bc->bc_mc, bc, candidate,  NULL, 0 , 0);
+			break;
+		case LDAP_REQ_ADD:
+			retcode = asyncmeta_back_add_start( &bc->copy_op, &bc->rs, bc->bc_mc, bc, candidate, 0);
+			break;
+		case LDAP_REQ_MODIFY:
+			retcode = asyncmeta_back_modify_start( &bc->copy_op, &bc->rs, bc->bc_mc, bc, candidate, 0);
+			break;
+		case LDAP_REQ_MODRDN:
+			retcode = asyncmeta_back_modrdn_start( &bc->copy_op, &bc->rs, bc->bc_mc, bc, candidate, 0);
+			break;
+		case LDAP_REQ_COMPARE:
+			retcode = asyncmeta_back_compare_start( &bc->copy_op, &bc->rs, bc->bc_mc, bc, candidate, 0);
+			break;
+		case LDAP_REQ_DELETE:
+			retcode = asyncmeta_back_delete_start( &bc->copy_op, &bc->rs, bc->bc_mc, bc, candidate, 0);
+			break;
+		default:
+			retcode = META_SEARCH_NOT_CANDIDATE;
+		}
+	return retcode;
+}
+
+
+meta_search_candidate_t
+asyncmeta_send_all_pending_ops(a_metaconn_t *mc, int candidate, void *ctx, int dolock)
+{
+	a_metainfo_t	*mi = mc->mc_info;
+	bm_context_t *bc, *onext;
+	a_metasingleconn_t *msc = &mc->mc_conns[candidate];
+
+	if ( dolock )
+		ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex );
+
+	msc->msc_active++;
+	for (bc = LDAP_STAILQ_FIRST(&mc->mc_om_list); bc; bc = onext) {
+		meta_search_candidate_t ret;
+		onext = LDAP_STAILQ_NEXT(bc, bc_next);
+		if (bc->candidates[candidate].sr_msgid == META_MSGID_NEED_BIND)
+			bc->candidates[candidate].sr_msgid = META_MSGID_GOT_BIND;
+		if (bc->candidates[candidate].sr_msgid != META_MSGID_GOT_BIND || bc->bc_active > 0 || bc->op->o_abandon > 0) {
+			continue;
+		}
+		bc->op->o_threadctx = ctx;
+		bc->op->o_tid = ldap_pvt_thread_pool_tid( ctx );
+		slap_sl_mem_setctx(ctx, bc->op->o_tmpmemctx);
+		operation_counter_init( bc->op, ctx );
+		bc->bc_active++;
+		ret = asyncmeta_send_pending_op(bc, candidate);
+		if (ret != META_SEARCH_CANDIDATE) {
+			bc->candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+			bc->candidates[ candidate ].sr_type = REP_RESULT;
+			bc->candidates[ candidate ].sr_err = bc->rs.sr_err;
+			if (bc->op->o_tag != LDAP_REQ_SEARCH || (META_BACK_ONERR_STOP( mi )) ||
+			    (asyncmeta_is_last_result(mc, bc, candidate) == 0)) {
+				LDAP_STAILQ_REMOVE(&mc->mc_om_list, bc, bm_context_t, bc_next);
+				mc->pending_ops--;
+				asyncmeta_send_ldap_result(bc, bc->op, &bc->rs);
+				asyncmeta_clear_bm_context(bc);
+			}
+		} else {
+			bc->bc_active--;
+		}
+	}
+	msc->msc_active--;
+
+	if ( dolock )
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+
+	return META_SEARCH_CANDIDATE;
+}
+
+meta_search_candidate_t
+asyncmeta_return_bind_errors(a_metaconn_t *mc, int candidate, SlapReply *bind_result, void *ctx, int dolock)
+{
+	a_metainfo_t	*mi = mc->mc_info;
+	bm_context_t *bc, *onext;
+
+	if ( dolock )
+		ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex );
+
+	for (bc = LDAP_STAILQ_FIRST(&mc->mc_om_list); bc; bc = onext) {
+		onext = LDAP_STAILQ_NEXT(bc, bc_next);
+		if (bc->candidates[candidate].sr_msgid != META_MSGID_NEED_BIND
+		    || bc->bc_active > 0 || bc->op->o_abandon > 0) {
+			continue;
+		}
+		bc->candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		bc->candidates[ candidate ].sr_type = REP_RESULT;
+		bc->candidates[ candidate ].sr_err = bind_result->sr_err;
+		if (bc->op->o_tag != LDAP_REQ_SEARCH || (META_BACK_ONERR_STOP( mi )) ||
+		    (asyncmeta_is_last_result(mc, bc, candidate) == 0)) {
+			LDAP_STAILQ_REMOVE(&mc->mc_om_list, bc, bm_context_t, bc_next);
+			bc->op->o_threadctx = ctx;
+			bc->op->o_tid = ldap_pvt_thread_pool_tid( ctx );
+			slap_sl_mem_setctx(ctx, bc->op->o_tmpmemctx);
+			operation_counter_init( bc->op, ctx );
+			bc->rs.sr_err = bind_result->sr_err;
+			bc->rs.sr_text = bind_result->sr_text;
+			mc->pending_ops--;
+			asyncmeta_send_ldap_result(bc, bc->op, &bc->rs);
+			asyncmeta_clear_bm_context(bc);
+		}
+	}
+
+	if ( dolock )
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+
+	return META_SEARCH_CANDIDATE;
+}
+
+static meta_search_candidate_t
+asyncmeta_handle_bind_result(LDAPMessage *msg, a_metaconn_t *mc, int candidate, void *ctx)
+{
+	meta_search_candidate_t	retcode;
+	SlapReply bind_result = {0};
+	/* could modify the msc, safer to lock it */
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex );
+	retcode = asyncmeta_dobind_result( mc, candidate, &bind_result, msg );
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+	if ( retcode == META_SEARCH_CANDIDATE ) {
+		/* send the remaining pending ops */
+		asyncmeta_send_all_pending_ops(mc, candidate, ctx, 1);
+	} else {
+		asyncmeta_return_bind_errors(mc, candidate, &bind_result, ctx, 1);
+	}
+	return retcode;
+}
+
+int
+asyncmeta_handle_search_msg(LDAPMessage *res, a_metaconn_t *mc, bm_context_t *bc, int candidate)
+{
+	a_metainfo_t	*mi;
+	a_metatarget_t	*mt;
+	a_metasingleconn_t *msc;
+	Operation *op = bc->op;
+	SlapReply *rs;
+	int	   i, rc = LDAP_SUCCESS, sres;
+	SlapReply *candidates;
+	char		**references = NULL;
+	LDAPControl	**ctrls = NULL;
+	a_dncookie dc;
+	LDAPMessage *msg;
+	ber_int_t id;
+
+	rs = &bc->rs;
+	mi = mc->mc_info;
+	mt = mi->mi_targets[ candidate ];
+	msc = &mc->mc_conns[ candidate ];
+	dc.op = op;
+	dc.target = mt;
+	dc.to_from = MASSAGE_REP;
+	id = ldap_msgid(res);
+
+
+	candidates = bc->candidates;
+	i = candidate;
+
+	while (res && !META_BACK_CONN_INVALID(msc)) {
+	for (msg = ldap_first_message(msc->msc_ldr, res); msg; msg = ldap_next_message(msc->msc_ldr, msg)) {
+		switch(ldap_msgtype(msg)) {
+		case LDAP_RES_SEARCH_ENTRY:
+			Debug( LDAP_DEBUG_TRACE,
+				"%s asyncmeta_handle_search_msg: msc %p entry\n",
+				op->o_log_prefix, msc );
+			if ( candidates[ i ].sr_type == REP_INTERMEDIATE ) {
+				/* don't retry any more... */
+				candidates[ i ].sr_type = REP_RESULT;
+			}
+			/* count entries returned by target */
+			candidates[ i ].sr_nentries++;
+			if (bc->c_peer_name.bv_val == op->o_conn->c_peer_name.bv_val && !op->o_abandon) {
+				rs->sr_err = asyncmeta_send_entry( &bc->copy_op, rs, mc, i, msg );
+			} else {
+				goto err_cleanup;
+			}
+			switch ( rs->sr_err ) {
+			case LDAP_SIZELIMIT_EXCEEDED:
+				asyncmeta_send_ldap_result(bc, op, rs);
+				rs->sr_err = LDAP_SUCCESS;
+				goto err_cleanup;
+			case LDAP_UNAVAILABLE:
+				rs->sr_err = LDAP_OTHER;
+				break;
+			default:
+				break;
+			}
+			bc->is_ok++;
+			break;
+
+		case LDAP_RES_SEARCH_REFERENCE:
+			if ( META_BACK_TGT_NOREFS( mt ) ) {
+				rs->sr_err = LDAP_OTHER;
+				asyncmeta_send_ldap_result(bc, op, rs);
+				goto err_cleanup;
+			}
+			if ( candidates[ i ].sr_type == REP_INTERMEDIATE ) {
+				/* don't retry any more... */
+				candidates[ i ].sr_type = REP_RESULT;
+			}
+			bc->is_ok++;
+			rc = ldap_parse_reference( msc->msc_ldr, msg,
+				   &references, &rs->sr_ctrls, 0 );
+
+			if ( rc != LDAP_SUCCESS || references == NULL ) {
+				rs->sr_err = LDAP_OTHER;
+				asyncmeta_send_ldap_result(bc, op, rs);
+				goto err_cleanup;
+			}
+
+			/* FIXME: merge all and return at the end */
+
+			{
+				int cnt;
+				for ( cnt = 0; references[ cnt ]; cnt++ )
+					;
+
+				rs->sr_ref = op->o_tmpalloc( sizeof( struct berval ) * ( cnt + 1 ),
+								 op->o_tmpmemctx );
+
+				for ( cnt = 0; references[ cnt ]; cnt++ ) {
+					ber_str2bv_x( references[ cnt ], 0, 1, &rs->sr_ref[ cnt ],
+							  op->o_tmpmemctx );
+				}
+				BER_BVZERO( &rs->sr_ref[ cnt ] );
+			}
+
+			{
+				dc.memctx = op->o_tmpmemctx;
+				( void )asyncmeta_referral_result_rewrite( &dc, rs->sr_ref );
+			}
+
+			if ( rs->sr_ref != NULL ) {
+				if (!BER_BVISNULL( &rs->sr_ref[ 0 ] ) ) {
+					/* ignore return value by now */
+					( void )send_search_reference( op, rs );
+				}
+
+				ber_bvarray_free_x( rs->sr_ref, op->o_tmpmemctx );
+				rs->sr_ref = NULL;
+			}
+
+			/* cleanup */
+			if ( references ) {
+				ber_memvfree( (void **)references );
+			}
+
+			if ( rs->sr_ctrls ) {
+				ldap_controls_free( rs->sr_ctrls );
+				rs->sr_ctrls = NULL;
+			}
+			break;
+
+		case LDAP_RES_INTERMEDIATE:
+			if ( candidates[ i ].sr_type == REP_INTERMEDIATE ) {
+				/* don't retry any more... */
+				candidates[ i ].sr_type = REP_RESULT;
+			}
+			bc->is_ok++;
+
+			/* FIXME: response controls
+			 * are passed without checks */
+			rs->sr_err = ldap_parse_intermediate( msc->msc_ldr,
+								  msg,
+								  (char **)&rs->sr_rspoid,
+								  &rs->sr_rspdata,
+								  &rs->sr_ctrls,
+								  0 );
+			if ( rs->sr_err != LDAP_SUCCESS ) {
+				candidates[ i ].sr_type = REP_RESULT;
+				rs->sr_err = LDAP_OTHER;
+				asyncmeta_send_ldap_result(bc, op, rs);
+				goto err_cleanup;
+			}
+
+			slap_send_ldap_intermediate( op, rs );
+
+			if ( rs->sr_rspoid != NULL ) {
+				ber_memfree( (char *)rs->sr_rspoid );
+				rs->sr_rspoid = NULL;
+			}
+
+			if ( rs->sr_rspdata != NULL ) {
+				ber_bvfree( rs->sr_rspdata );
+				rs->sr_rspdata = NULL;
+			}
+
+			if ( rs->sr_ctrls != NULL ) {
+				ldap_controls_free( rs->sr_ctrls );
+				rs->sr_ctrls = NULL;
+			}
+			break;
+
+		case LDAP_RES_SEARCH_RESULT:
+			if ( mi->mi_idle_timeout != 0 ) {
+				asyncmeta_set_msc_time(msc);
+			}
+			Debug( LDAP_DEBUG_TRACE,
+			       "%s asyncmeta_handle_search_msg: msc %p result\n",
+			       op->o_log_prefix, msc );
+			candidates[ i ].sr_type = REP_RESULT;
+			candidates[ i ].sr_msgid = META_MSGID_IGNORE;
+			/* NOTE: ignores response controls
+			 * (and intermediate response controls
+			 * as well, except for those with search
+			 * references); this may not be correct,
+			 * but if they're not ignored then
+			 * back-meta would need to merge them
+			 * consistently (think of pagedResults...)
+			 */
+			/* FIXME: response controls? */
+			rs->sr_err = ldap_parse_result( msc->msc_ldr,
+							msg,
+							&candidates[ i ].sr_err,
+								(char **)&candidates[ i ].sr_matched,
+							(char **)&candidates[ i ].sr_text,
+							&references,
+							&ctrls /* &candidates[ i ].sr_ctrls (unused) */ ,
+							0 );
+			if ( rs->sr_err != LDAP_SUCCESS ) {
+				candidates[ i ].sr_err = rs->sr_err;
+				sres = slap_map_api2result( &candidates[ i ] );
+				candidates[ i ].sr_type = REP_RESULT;
+				goto finish;
+			}
+
+			rs->sr_err = candidates[ i ].sr_err;
+
+			/* massage matchedDN if need be */
+			if ( candidates[ i ].sr_matched != NULL ) {
+				struct berval	match, mmatch;
+
+				ber_str2bv( candidates[ i ].sr_matched,
+						0, 0, &match );
+				candidates[ i ].sr_matched = NULL;
+
+				dc.memctx = NULL;
+				asyncmeta_dn_massage( &dc, &match, &mmatch );
+				if ( mmatch.bv_val == match.bv_val ) {
+					candidates[ i ].sr_matched
+						= ch_strdup( mmatch.bv_val );
+
+				} else {
+					candidates[ i ].sr_matched = mmatch.bv_val;
+				}
+
+				bc->candidate_match++;
+				ldap_memfree( match.bv_val );
+			}
+
+			/* add references to array */
+			/* RFC 4511: referrals can only appear
+			 * if result code is LDAP_REFERRAL */
+			if ( references != NULL
+				 && references[ 0 ] != NULL
+				 && references[ 0 ][ 0 ] != '\0' )
+			{
+				if ( rs->sr_err != LDAP_REFERRAL ) {
+					Debug( LDAP_DEBUG_ANY,
+						   "%s asncmeta_search_result[%d]: "
+						   "got referrals with err=%d\n",
+						   op->o_log_prefix,
+						   i, rs->sr_err );
+
+				} else {
+					BerVarray	sr_ref;
+					int		cnt;
+
+					for ( cnt = 0; references[ cnt ]; cnt++ )
+						;
+
+					sr_ref = op->o_tmpalloc( sizeof( struct berval ) * ( cnt + 1 ),
+								 op->o_tmpmemctx );
+
+					for ( cnt = 0; references[ cnt ]; cnt++ ) {
+						ber_str2bv_x( references[ cnt ], 0, 1, &sr_ref[ cnt ],
+								  op->o_tmpmemctx );
+					}
+					BER_BVZERO( &sr_ref[ cnt ] );
+
+					dc.memctx = op->o_tmpmemctx;
+					( void )asyncmeta_referral_result_rewrite( &dc, sr_ref );
+
+					if ( rs->sr_v2ref == NULL ) {
+						rs->sr_v2ref = sr_ref;
+
+					} else {
+						for ( cnt = 0; !BER_BVISNULL( &sr_ref[ cnt ] ); cnt++ ) {
+							ber_bvarray_add_x( &rs->sr_v2ref, &sr_ref[ cnt ],
+									   op->o_tmpmemctx );
+						}
+						ber_memfree_x( sr_ref, op->o_tmpmemctx );
+					}
+				}
+
+			} else if ( rs->sr_err == LDAP_REFERRAL ) {
+				Debug( LDAP_DEBUG_TRACE,
+					   "%s asyncmeta_search_result[%d]: "
+					   "got err=%d with null "
+					   "or empty referrals\n",
+					   op->o_log_prefix,
+					   i, rs->sr_err );
+
+				rs->sr_err = LDAP_NO_SUCH_OBJECT;
+			}
+
+			/* cleanup */
+			ber_memvfree( (void **)references );
+
+			sres = slap_map_api2result( rs );
+
+			if ( candidates[ i ].sr_err == LDAP_SUCCESS ) {
+				Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_search_result[%d] "
+				       "match=\"%s\" err=%ld\n",
+				       op->o_log_prefix, i,
+				       candidates[ i ].sr_matched ? candidates[ i ].sr_matched : "",
+				       (long) candidates[ i ].sr_err );
+			} else {
+					Debug( LDAP_DEBUG_ANY,  "%s asyncmeta_search_result[%d] "
+				       "match=\"%s\" err=%ld (%s)\n",
+				       op->o_log_prefix, i,
+				       candidates[ i ].sr_matched ? candidates[ i ].sr_matched : "",
+					       (long) candidates[ i ].sr_err, ldap_err2string( candidates[ i ].sr_err ) );
+			}
+
+			switch ( sres ) {
+			case LDAP_NO_SUCH_OBJECT:
+				/* is_ok is touched any time a valid
+				 * (even intermediate) result is
+				 * returned; as a consequence, if
+				 * a candidate returns noSuchObject
+				 * it is ignored and the candidate
+				 * is simply demoted. */
+				if ( bc->is_ok ) {
+					sres = LDAP_SUCCESS;
+				}
+				break;
+
+			case LDAP_SUCCESS:
+				if ( ctrls != NULL && ctrls[0] != NULL ) {
+#ifdef SLAPD_META_CLIENT_PR
+					LDAPControl *pr_c;
+
+					pr_c = ldap_control_find( LDAP_CONTROL_PAGEDRESULTS, ctrls, NULL );
+					if ( pr_c != NULL ) {
+						BerElementBuffer berbuf;
+						BerElement *ber = (BerElement *)&berbuf;
+						ber_tag_t tag;
+						ber_int_t prsize;
+						struct berval prcookie;
+
+						/* unsolicited, do not accept */
+						if ( mt->mt_ps == 0 ) {
+							rs->sr_err = LDAP_OTHER;
+							goto err_pr;
+						}
+
+						ber_init2( ber, &pr_c->ldctl_value, LBER_USE_DER );
+
+						tag = ber_scanf( ber, "{im}", &prsize, &prcookie );
+						if ( tag == LBER_ERROR ) {
+							rs->sr_err = LDAP_OTHER;
+							goto err_pr;
+						}
+
+						/* more pages? new search request */
+						if ( !BER_BVISNULL( &prcookie ) && !BER_BVISEMPTY( &prcookie ) ) {
+							if ( mt->mt_ps > 0 ) {
+								/* ignore size if specified */
+								prsize = 0;
+
+							} else if ( prsize == 0 ) {
+								/* guess the page size from the entries returned so far */
+								prsize = candidates[ i ].sr_nentries;
+							}
+
+							candidates[ i ].sr_nentries = 0;
+							candidates[ i ].sr_msgid = META_MSGID_IGNORE;
+							candidates[ i ].sr_type = REP_INTERMEDIATE;
+
+							assert( candidates[ i ].sr_matched == NULL );
+							assert( candidates[ i ].sr_text == NULL );
+							assert( candidates[ i ].sr_ref == NULL );
+
+							switch ( asyncmeta_back_search_start( &bc->copy_op, rs, mc, bc, i, &prcookie, prsize, 1 ) )
+							{
+							case META_SEARCH_CANDIDATE:
+								assert( candidates[ i ].sr_msgid >= 0 );
+								ldap_controls_free( ctrls );
+								//	goto free_message;
+
+							case META_SEARCH_ERR:
+							case META_SEARCH_NEED_BIND:
+err_pr:;
+								candidates[ i ].sr_err = rs->sr_err;
+								candidates[ i ].sr_type = REP_RESULT;
+								if ( META_BACK_ONERR_STOP( mi ) ) {
+									asyncmeta_send_ldap_result(bc, op, rs);
+									ldap_controls_free( ctrls );
+									goto err_cleanup;
+								}
+								/* fallthru */
+
+							case META_SEARCH_NOT_CANDIDATE:
+								/* means that asyncmeta_back_search_start()
+								 * failed but onerr == continue */
+								candidates[ i ].sr_msgid = META_MSGID_IGNORE;
+								candidates[ i ].sr_type = REP_RESULT;
+								break;
+
+							default:
+								/* impossible */
+								assert( 0 );
+								break;
+							}
+							break;
+						}
+					}
+#endif /* SLAPD_META_CLIENT_PR */
+
+					ldap_controls_free( ctrls );
+				}
+				/* fallthru */
+
+			case LDAP_REFERRAL:
+				bc->is_ok++;
+				break;
+
+			case LDAP_SIZELIMIT_EXCEEDED:
+				/* if a target returned sizelimitExceeded
+				 * and the entry count is equal to the
+				 * proxy's limit, the target would have
+				 * returned more, and the error must be
+				 * propagated to the client; otherwise,
+				 * the target enforced a limit lower
+				 * than what requested by the proxy;
+				 * ignore it */
+				candidates[ i ].sr_err = rs->sr_err;
+				if ( rs->sr_nentries == op->ors_slimit
+					 || META_BACK_ONERR_STOP( mi ) )
+				{
+					const char *save_text;
+got_err:
+					save_text = rs->sr_text;
+					rs->sr_text = candidates[ i ].sr_text;
+					asyncmeta_send_ldap_result(bc, op, rs);
+					if (candidates[ i ].sr_text != NULL) {
+						ch_free( (char *)candidates[ i ].sr_text );
+						candidates[ i ].sr_text = NULL;
+					}
+					rs->sr_text = save_text;
+					ldap_controls_free( ctrls );
+					goto err_cleanup;
+				}
+				break;
+
+			default:
+				candidates[ i ].sr_err = rs->sr_err;
+				if ( META_BACK_ONERR_STOP( mi ) ) {
+					goto got_err;
+				}
+				break;
+			}
+			/* if this is the last result we will ever receive, send it back  */
+			rc = rs->sr_err;
+			if (asyncmeta_is_last_result(mc, bc, i) == 0) {
+				Debug( LDAP_DEBUG_TRACE,
+					"%s asyncmeta_handle_search_msg: msc %p last result\n",
+					op->o_log_prefix, msc );
+				asyncmeta_search_last_result(mc, bc, i, sres);
+err_cleanup:
+				rc = rs->sr_err;
+				ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex );
+				asyncmeta_drop_bc( mc, bc);
+				asyncmeta_clear_bm_context(bc);
+				ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+				ldap_msgfree(res);
+				return rc;
+			}
+finish:
+			break;
+
+		default:
+			continue;
+		}
+	}
+		ldap_msgfree(res);
+		res = NULL;
+		if (candidates[ i ].sr_type != REP_RESULT) {
+			struct timeval	tv = {0};
+			rc = ldap_result( msc->msc_ldr, id, LDAP_MSG_RECEIVED, &tv, &res );
+			if (res != NULL) {
+				msc->msc_result_time = slap_get_time();
+			}
+		}
+	}
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex );
+	bc->bc_active--;
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+
+	return rc;
+}
+
+/* handles the received result for add, modify, modrdn, compare and delete ops */
+
+int asyncmeta_handle_common_result(LDAPMessage *msg, a_metaconn_t *mc, bm_context_t *bc, int candidate)
+{
+	a_metainfo_t	*mi;
+	a_metatarget_t	*mt;
+	a_metasingleconn_t *msc;
+	const char	*save_text = NULL,
+		*save_matched = NULL;
+	BerVarray	save_ref = NULL;
+	LDAPControl	**save_ctrls = NULL;
+	void		*matched_ctx = NULL;
+
+	char		*matched = NULL;
+	char		*text = NULL;
+	char		**refs = NULL;
+	LDAPControl	**ctrls = NULL;
+	Operation *op;
+	SlapReply *rs;
+	int		rc;
+
+	mi = mc->mc_info;
+	mt = mi->mi_targets[ candidate ];
+	msc = &mc->mc_conns[ candidate ];
+
+	op = bc->op;
+	rs = &bc->rs;
+	save_text = rs->sr_text,
+	save_matched = rs->sr_matched;
+	save_ref = rs->sr_ref;
+	save_ctrls = rs->sr_ctrls;
+	rs->sr_text = NULL;
+	rs->sr_matched = NULL;
+	rs->sr_ref = NULL;
+	rs->sr_ctrls = NULL;
+
+	/* only touch when activity actually took place... */
+	if ( mi->mi_idle_timeout != 0 ) {
+		asyncmeta_set_msc_time(msc);
+	}
+
+	rc = ldap_parse_result( msc->msc_ldr, msg, &rs->sr_err,
+				&matched, &text, &refs, &ctrls, 0 );
+
+	if ( rc == LDAP_SUCCESS ) {
+		rs->sr_text = text;
+	} else {
+		rs->sr_err = rc;
+	}
+	rs->sr_err = slap_map_api2result( rs );
+
+	/* RFC 4511: referrals can only appear
+	 * if result code is LDAP_REFERRAL */
+	if ( refs != NULL
+	     && refs[ 0 ] != NULL
+	     && refs[ 0 ][ 0 ] != '\0' )
+	{
+		if ( rs->sr_err != LDAP_REFERRAL ) {
+			Debug( LDAP_DEBUG_ANY,
+			       "%s asyncmeta_handle_common_result[%d]: "
+			       "got referrals with err=%d\n",
+			       op->o_log_prefix,
+			       candidate, rs->sr_err );
+
+		} else {
+			int	i;
+
+			for ( i = 0; refs[ i ] != NULL; i++ )
+				/* count */ ;
+			rs->sr_ref = op->o_tmpalloc( sizeof( struct berval ) * ( i + 1 ),
+						     op->o_tmpmemctx );
+			for ( i = 0; refs[ i ] != NULL; i++ ) {
+				ber_str2bv( refs[ i ], 0, 0, &rs->sr_ref[ i ] );
+			}
+			BER_BVZERO( &rs->sr_ref[ i ] );
+		}
+
+	} else if ( rs->sr_err == LDAP_REFERRAL ) {
+		Debug( LDAP_DEBUG_ANY,
+		       "%s asyncmeta_handle_common_result[%d]: "
+		       "got err=%d with null "
+		       "or empty referrals\n",
+		       op->o_log_prefix,
+		       candidate, rs->sr_err );
+
+		rs->sr_err = LDAP_NO_SUCH_OBJECT;
+	}
+
+	if ( ctrls != NULL ) {
+		rs->sr_ctrls = ctrls;
+	}
+
+	/* if the error in the reply structure is not
+	 * LDAP_SUCCESS, try to map it from client
+	 * to server error */
+	if ( !LDAP_ERR_OK( rs->sr_err ) ) {
+		rs->sr_err = slap_map_api2result( rs );
+
+		/* internal ops ( op->o_conn == NULL )
+		 * must not reply to client */
+		if ( op->o_conn && !op->o_do_not_cache && matched ) {
+
+			/* record the (massaged) matched
+			 * DN into the reply structure */
+			rs->sr_matched = matched;
+		}
+	}
+
+	if ( META_BACK_TGT_QUARANTINE( mt ) ) {
+		asyncmeta_quarantine( op, mi, rs, candidate );
+	}
+
+	if ( matched != NULL ) {
+		struct berval	dn, pdn;
+
+		ber_str2bv( matched, 0, 0, &dn );
+		if ( dnPretty( NULL, &dn, &pdn, op->o_tmpmemctx ) == LDAP_SUCCESS ) {
+			ldap_memfree( matched );
+			matched_ctx = op->o_tmpmemctx;
+			matched = pdn.bv_val;
+		}
+		rs->sr_matched = matched;
+	}
+
+	if ( rs->sr_err == LDAP_UNAVAILABLE || rs->sr_err == LDAP_SERVER_DOWN ) {
+		if ( rs->sr_text == NULL ) {
+				rs->sr_text = "Target is unavailable";
+			}
+	}
+
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex );
+	asyncmeta_drop_bc( mc, bc);
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+
+	if ( op->o_conn ) {
+		asyncmeta_send_ldap_result(bc, op, rs);
+	}
+
+	if ( matched ) {
+		op->o_tmpfree( (char *)rs->sr_matched, matched_ctx );
+	}
+	if ( text ) {
+		ldap_memfree( text );
+	}
+	if ( rs->sr_ref ) {
+		op->o_tmpfree( rs->sr_ref, op->o_tmpmemctx );
+		rs->sr_ref = NULL;
+	}
+	if ( refs ) {
+		ber_memvfree( (void **)refs );
+	}
+	if ( ctrls ) {
+		assert( rs->sr_ctrls != NULL );
+		ldap_controls_free( ctrls );
+	}
+
+	rs->sr_text = save_text;
+	rs->sr_matched = save_matched;
+	rs->sr_ref = save_ref;
+	rs->sr_ctrls = save_ctrls;
+	rc = (LDAP_ERR_OK( rs->sr_err ) ? LDAP_SUCCESS : rs->sr_err);
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex );
+	asyncmeta_clear_bm_context(bc);
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+	return rc;
+}
+
+/* This takes care to clean out the outbound queue in case we have a read error
+ * sending back responses to the client */
+int
+asyncmeta_op_read_error(a_metaconn_t *mc, int candidate, int error, void* ctx)
+{
+	bm_context_t *bc, *onext;
+	int cleanup;
+	Operation *op;
+	SlapReply *rs;
+	SlapReply *candidates;
+
+	/* no outstanding ops, nothing to do but log */
+	Debug( LDAP_DEBUG_TRACE,
+	       "asyncmeta_op_read_error: ldr=%p, err=%d\n",
+	       mc->mc_conns[candidate].msc_ldr, error );
+
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex );
+	/*someone may be trying to write */
+	if (mc->mc_conns[candidate].msc_active <= 1) {
+		asyncmeta_clear_one_msc(NULL, mc, candidate, 0, __FUNCTION__);
+	} else {
+		META_BACK_CONN_INVALID_SET(&mc->mc_conns[candidate]);
+	}
+
+	if (mc->pending_ops <= 0) {
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+		return LDAP_SUCCESS;
+	}
+
+	for (bc = LDAP_STAILQ_FIRST(&mc->mc_om_list); bc; bc = onext) {
+		onext = LDAP_STAILQ_NEXT(bc, bc_next);
+		cleanup = 0;
+		candidates = bc->candidates;
+		/* was this op affected? */
+		if ( !META_IS_CANDIDATE( &candidates[ candidate ] ) )
+			continue;
+
+		if (bc->op->o_abandon) {
+			bc->bc_invalid = 1;
+			continue;
+		}
+
+		if (bc->bc_active > 0) {
+			bc->bc_invalid = 1;
+			continue;
+		}
+
+		bc->op->o_threadctx = ctx;
+		bc->op->o_tid = ldap_pvt_thread_pool_tid( ctx );
+		slap_sl_mem_setctx(ctx, bc->op->o_tmpmemctx);
+		operation_counter_init( bc->op, ctx );
+
+		op = bc->op;
+		rs = &bc->rs;
+		switch (op->o_tag) {
+		case LDAP_REQ_ADD:
+		case LDAP_REQ_MODIFY:
+		case LDAP_REQ_MODRDN:
+		case LDAP_REQ_COMPARE:
+		case LDAP_REQ_DELETE:
+			rs->sr_err = LDAP_UNAVAILABLE;
+			rs->sr_text = "Read error on connection to target";
+			asyncmeta_send_ldap_result( bc, op, rs );
+			cleanup = 1;
+			break;
+		case LDAP_REQ_SEARCH:
+		{
+			a_metainfo_t *mi = mc->mc_info;
+			rs->sr_err = LDAP_UNAVAILABLE;
+			rs->sr_text = "Read error on connection to target";
+			candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+			candidates[ candidate ].sr_type = REP_RESULT;
+			if ( (META_BACK_ONERR_STOP( mi ) ||
+			      asyncmeta_is_last_result(mc, bc, candidate)) && op->o_conn) {
+				asyncmeta_send_ldap_result( bc, op, rs );
+				cleanup = 1;
+			}
+		}
+			break;
+		default:
+			break;
+		}
+
+		if (cleanup) {
+			int j;
+			a_metainfo_t *mi = mc->mc_info;
+			for (j=0; j<mi->mi_ntargets; j++) {
+				if (j != candidate && bc->candidates[j].sr_msgid >= 0
+				    && mc->mc_conns[j].msc_ld != NULL) {
+					asyncmeta_back_cancel( mc, op,
+							       bc->candidates[ j ].sr_msgid, j );
+				}
+			}
+			LDAP_STAILQ_REMOVE(&mc->mc_om_list, bc, bm_context_t, bc_next);
+			mc->pending_ops--;
+			asyncmeta_clear_bm_context(bc);
+		}
+	}
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+	return LDAP_SUCCESS;
+}
+
+void *
+asyncmeta_op_handle_result(void *ctx, void *arg)
+{
+	a_metaconn_t *mc = arg;
+	int		i, j, rc, ntargets;
+	struct timeval	tv = {0};
+	LDAPMessage     *msg;
+	a_metasingleconn_t *msc;
+	bm_context_t *bc;
+	void *oldctx;
+
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex );
+	rc = ++mc->mc_active;
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+	if (rc > 1)
+		return NULL;
+
+	ntargets = mc->mc_info->mi_ntargets;
+	i = ntargets;
+	oldctx = slap_sl_mem_create(SLAP_SLAB_SIZE, SLAP_SLAB_STACK, ctx, 0);	/* get existing memctx */
+
+again:
+	for (j=0; j<ntargets; j++) {
+		i++;
+		if (i >= ntargets) i = 0;
+		msc = &mc->mc_conns[i];
+		ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex );
+		if (!mc->mc_conns[i].msc_ldr ||
+		    META_BACK_CONN_CREATING( &mc->mc_conns[i] ) ||
+		    META_BACK_CONN_INVALID(&mc->mc_conns[i])) {
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+			continue;
+		}
+
+		msc->msc_active++;
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+
+		rc = ldap_result( mc->mc_conns[i].msc_ldr, LDAP_RES_ANY, LDAP_MSG_RECEIVED, &tv, &msg );
+		if (rc < 1) {
+			if (rc < 0) {
+				ldap_get_option( mc->mc_conns[i].msc_ldr, LDAP_OPT_ERROR_NUMBER, &rc);
+				META_BACK_CONN_INVALID_SET(&mc->mc_conns[i]);
+				asyncmeta_op_read_error(mc, i, rc, ctx);
+			}
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex );
+			msc->msc_active--;
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+			continue;
+		}
+		rc = ldap_msgtype( msg );
+		if (rc == LDAP_RES_BIND) {
+			if ( LogTest( asyncmeta_debug ) ) {
+				char	time_buf[ SLAP_TEXT_BUFLEN ];
+				asyncmeta_get_timestamp(time_buf);
+				Debug( asyncmeta_debug, "[%s] asyncmeta_op_handle_result received bind msgid=%d msc: %p\n",
+				      time_buf, ldap_msgid(msg), msc );
+			}
+			asyncmeta_handle_bind_result(msg, mc, i, ctx);
+			mc->mc_info->mi_targets[i]->mt_timeout_ops = 0;
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex );
+			msc->msc_result_time = slap_get_time();
+			msc->msc_active--;
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+			if (msg)
+				ldap_msgfree(msg);
+
+			continue;
+		}
+retry_bc:
+		ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex );
+		bc = asyncmeta_find_message(ldap_msgid(msg), mc, i);
+/* The sender might not be yet done with the context. On error it might also remove it
+ * so it's best to try and find it again after a wait */
+		if (bc && bc->bc_active > 0) {
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+			ldap_pvt_thread_yield();
+			goto retry_bc;
+		}
+		if (bc) {
+			bc->bc_active++;
+		}
+
+		msc->msc_result_time = slap_get_time();
+		msc->msc_active--;
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+		if (!bc) {
+			Debug( asyncmeta_debug,
+				"asyncmeta_op_handle_result: Unable to find bc for msguid %d, msc: %p\n", ldap_msgid(msg), msc );
+			ldap_msgfree(msg);
+			continue;
+		}
+
+		/* set our memctx */
+		bc->op->o_threadctx = ctx;
+		bc->op->o_tid = ldap_pvt_thread_pool_tid( ctx );
+		slap_sl_mem_setctx(ctx, bc->op->o_tmpmemctx);
+		operation_counter_init( bc->op, ctx );
+		if (bc->op->o_abandon) {
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex );
+			asyncmeta_drop_bc( mc, bc);
+			if ( bc->op->o_tag == LDAP_REQ_SEARCH ) {
+				int j;
+				for (j=0; j<ntargets; j++) {
+					if (bc->candidates[j].sr_msgid >= 0) {
+						a_metasingleconn_t *tmp_msc = &mc->mc_conns[j];
+						tmp_msc->msc_active++;
+						asyncmeta_back_cancel( mc, bc->op,
+								       bc->candidates[ j ].sr_msgid, j );
+						tmp_msc->msc_active--;
+					}
+				}
+			}
+			asyncmeta_clear_bm_context(bc);
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+			if (msg)
+				ldap_msgfree(msg);
+			continue;
+		}
+
+		switch (rc) {
+		case LDAP_RES_SEARCH_ENTRY:
+		case LDAP_RES_SEARCH_REFERENCE:
+		case LDAP_RES_SEARCH_RESULT:
+		case LDAP_RES_INTERMEDIATE:
+			asyncmeta_handle_search_msg(msg, mc, bc, i);
+			mc->mc_info->mi_targets[i]->mt_timeout_ops = 0;
+			msg = NULL;
+			break;
+		case LDAP_RES_ADD:
+		case LDAP_RES_DELETE:
+		case LDAP_RES_MODDN:
+		case LDAP_RES_COMPARE:
+		case LDAP_RES_MODIFY:
+			rc = asyncmeta_handle_common_result(msg, mc, bc, i);
+			mc->mc_info->mi_targets[i]->mt_timeout_ops = 0;
+			break;
+		default:
+			{
+			Debug( asyncmeta_debug,
+				   "asyncmeta_op_handle_result: "
+				   "unrecognized response message tag=%d\n",
+				   rc );
+
+			}
+		}
+		if (msg)
+			ldap_msgfree(msg);
+	}
+
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex );
+	rc = --mc->mc_active;
+	if (rc) {
+		i++;
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+		goto again;
+	}
+	slap_sl_mem_setctx(ctx, oldctx);
+	if (mc->mc_conns) {
+		for (i=0; i<ntargets; i++) {
+			if (!slapd_shutdown && !META_BACK_CONN_INVALID(msc)
+			    && mc->mc_conns[i].msc_ldr && mc->mc_conns[i].conn) {
+				connection_client_enable(mc->mc_conns[i].conn);
+			}
+		}
+	}
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+	return NULL;
+}
+
+void asyncmeta_set_msc_time(a_metasingleconn_t *msc)
+{
+	msc->msc_time = slap_get_time();
+}
+
+void* asyncmeta_timeout_loop(void *ctx, void *arg)
+{
+	struct re_s* rtask = arg;
+	a_metainfo_t *mi = rtask->arg;
+	bm_context_t *bc, *onext;
+	time_t current_time = slap_get_time();
+	int i, j;
+	LDAP_STAILQ_HEAD(BCList, bm_context_t) timeout_list;
+	LDAP_STAILQ_INIT( &timeout_list );
+
+	Debug( asyncmeta_debug, "asyncmeta_timeout_loop[%p] start at [%ld] \n", rtask, current_time );
+	void *oldctx = slap_sl_mem_create(SLAP_SLAB_SIZE, SLAP_SLAB_STACK, ctx, 0);
+	for (i=0; i<mi->mi_num_conns; i++) {
+		a_metaconn_t * mc= &mi->mi_conns[i];
+		ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex );
+		for (bc = LDAP_STAILQ_FIRST(&mc->mc_om_list); bc; bc = onext) {
+			onext = LDAP_STAILQ_NEXT(bc, bc_next);
+			if (bc->bc_active > 0) {
+				continue;
+			}
+
+			if (bc->op->o_abandon ) {
+				Operation *op = bc->op;
+
+				/* set our memctx */
+				op->o_threadctx = ctx;
+				op->o_tid = ldap_pvt_thread_pool_tid( ctx );
+				slap_sl_mem_setctx(ctx, op->o_tmpmemctx);
+				operation_counter_init( op, ctx );
+
+				LDAP_STAILQ_REMOVE(&mc->mc_om_list, bc, bm_context_t, bc_next);
+				mc->pending_ops--;
+				for (j=0; j<mi->mi_ntargets; j++) {
+					if (bc->candidates[j].sr_msgid >= 0) {
+						a_metasingleconn_t *msc = &mc->mc_conns[j];
+						if ( op->o_tag == LDAP_REQ_SEARCH ) {
+							msc->msc_active++;
+							asyncmeta_back_cancel( mc, op,
+									       bc->candidates[ j ].sr_msgid, j );
+							msc->msc_active--;
+						}
+					}
+				}
+				asyncmeta_clear_bm_context(bc);
+				continue;
+			}
+			if (bc->bc_invalid) {
+				LDAP_STAILQ_REMOVE(&mc->mc_om_list, bc, bm_context_t, bc_next);
+				mc->pending_ops--;
+				LDAP_STAILQ_INSERT_TAIL( &timeout_list, bc, bc_next);
+				continue;
+			}
+
+			if (bc->timeout && bc->stoptime < current_time) {
+				Operation *op = bc->op;
+				LDAP_STAILQ_REMOVE(&mc->mc_om_list, bc, bm_context_t, bc_next);
+				mc->pending_ops--;
+				LDAP_STAILQ_INSERT_TAIL( &timeout_list, bc, bc_next);
+				for (j=0; j<mi->mi_ntargets; j++) {
+					if (bc->candidates[j].sr_msgid >= 0) {
+						a_metasingleconn_t *msc = &mc->mc_conns[j];
+						asyncmeta_set_msc_time(msc);
+						if ( op->o_tag == LDAP_REQ_SEARCH ) {
+							msc->msc_active++;
+							asyncmeta_back_cancel( mc, op,
+									       bc->candidates[ j ].sr_msgid, j );
+							msc->msc_active--;
+						}
+					}
+				}
+			}
+		}
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+
+		for (bc = LDAP_STAILQ_FIRST(&timeout_list); bc; bc = onext) {
+			Operation *op = bc->op;
+			SlapReply *rs = &bc->rs;
+			int		timeout_err;
+			const char *timeout_text;
+
+			onext = LDAP_STAILQ_NEXT(bc, bc_next);
+			LDAP_STAILQ_REMOVE(&timeout_list, bc, bm_context_t, bc_next);
+			/* set our memctx */
+			bc->op->o_threadctx = ctx;
+			bc->op->o_tid = ldap_pvt_thread_pool_tid( ctx );
+			slap_sl_mem_setctx(ctx, bc->op->o_tmpmemctx);
+			operation_counter_init( bc->op, ctx );
+
+			if (bc->searchtime) {
+				timeout_err = LDAP_TIMELIMIT_EXCEEDED;
+			} else {
+				timeout_err = op->o_protocol >= LDAP_VERSION3 ?
+					LDAP_ADMINLIMIT_EXCEEDED : LDAP_OTHER;
+			}
+
+			if ( bc->bc_invalid ) {
+				timeout_text = "Operation is invalid - target connection has been reset";
+			} else {
+				a_metasingleconn_t *log_msc =  &mc->mc_conns[0];
+				Debug( asyncmeta_debug,
+				       "asyncmeta_timeout_loop:Timeout op %s loop[%p], "
+				       "current_time:%ld, op->o_time:%ld msc: %p, "
+				       "msc->msc_binding_time: %x, msc->msc_flags:%x \n",
+				       bc->op->o_log_prefix, rtask, current_time, bc->op->o_time,
+				       log_msc, (unsigned int)log_msc->msc_binding_time, log_msc->msc_mscflags );
+
+				if (bc->searchtime) {
+					timeout_text = NULL;
+				} else {
+					timeout_text = "Operation timed out";
+				}
+
+				for (j=0; j<mi->mi_ntargets; j++) {
+					if (bc->candidates[j].sr_msgid >= 0) {
+						a_metatarget_t     *mt = mi->mi_targets[j];
+						if (!META_BACK_TGT_QUARANTINE( mt ) ||
+						    bc->candidates[j].sr_type == REP_RESULT) {
+							continue;
+						}
+
+						if (mt->mt_isquarantined > LDAP_BACK_FQ_NO) {
+							timeout_err = LDAP_UNAVAILABLE;
+						} else {
+							mt->mt_timeout_ops++;
+							if ((mi->mi_max_timeout_ops > 0) &&
+							    (mt->mt_timeout_ops > mi->mi_max_timeout_ops)) {
+								timeout_err = LDAP_UNAVAILABLE;
+								rs->sr_err = timeout_err;
+								if (mt->mt_isquarantined == LDAP_BACK_FQ_NO)
+									asyncmeta_quarantine(op, mi, rs, j);
+							}
+						}
+					}
+				}
+			}
+			rs->sr_err = timeout_err;
+			rs->sr_text = timeout_text;
+			if (!bc->op->o_abandon ) {
+				asyncmeta_send_ldap_result( bc, bc->op, &bc->rs );
+			}
+			asyncmeta_clear_bm_context(bc);
+		}
+
+		ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex );
+		if (mi->mi_idle_timeout) {
+			for (j=0; j<mi->mi_ntargets; j++) {
+				a_metasingleconn_t *msc = &mc->mc_conns[j];
+				if ( msc->msc_active > 0 ) {
+					continue;
+				}
+				if (mc->pending_ops > 0) {
+					continue;
+				}
+				current_time = slap_get_time();
+				if (msc->msc_ld && msc->msc_time > 0 && msc->msc_time + mi->mi_idle_timeout < current_time) {
+					asyncmeta_clear_one_msc(NULL, mc, j, 1, __FUNCTION__);
+				}
+			}
+		}
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex );
+	}
+
+	slap_sl_mem_setctx(ctx, oldctx);
+	current_time = slap_get_time();
+	Debug( asyncmeta_debug, "asyncmeta_timeout_loop[%p] stop at [%ld] \n", rtask, current_time );
+	ldap_pvt_thread_mutex_lock( &slapd_rq.rq_mutex );
+	if ( ldap_pvt_runqueue_isrunning( &slapd_rq, rtask )) {
+		ldap_pvt_runqueue_stoptask( &slapd_rq, rtask );
+	}
+	ldap_pvt_thread_mutex_unlock( &slapd_rq.rq_mutex );
+	return NULL;
+}
+
diff --git a/servers/slapd/back-asyncmeta/modify.c b/servers/slapd/back-asyncmeta/modify.c
new file mode 100644
index 0000000..a70bae8
--- /dev/null
+++ b/servers/slapd/back-asyncmeta/modify.c
@@ -0,0 +1,357 @@
+/* modify.c - modify request handler for back-asyncmeta */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016-2022 The OpenLDAP Foundation.
+ * Portions Copyright 2016 Symas Corporation.
+ * 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 developed by Symas Corporation
+ * based on back-meta module for inclusion in OpenLDAP Software.
+ * This work was sponsored by Ericsson. */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/string.h>
+#include <ac/socket.h>
+#include "slap.h"
+#include "../../../libraries/liblber/lber-int.h"
+#include "../../../libraries/libldap/ldap-int.h"
+#include "../back-ldap/back-ldap.h"
+#include "back-asyncmeta.h"
+
+meta_search_candidate_t
+asyncmeta_back_modify_start(Operation *op,
+			    SlapReply *rs,
+			    a_metaconn_t *mc,
+			    bm_context_t *bc,
+			    int candidate,
+			    int do_lock)
+{
+	int		i, isupdate, rc = 0;
+	a_dncookie	dc;
+	a_metainfo_t	*mi = mc->mc_info;
+	a_metatarget_t	*mt = mi->mi_targets[ candidate ];
+	LDAPMod		**modv = NULL;
+	LDAPMod		*mods = NULL;
+	struct berval mdn;
+	Modifications	*ml;
+	meta_search_candidate_t retcode = META_SEARCH_CANDIDATE;
+		BerElement *ber = NULL;
+	a_metasingleconn_t	*msc = &mc->mc_conns[ candidate ];
+	SlapReply		*candidates = bc->candidates;
+	ber_int_t	msgid;
+	LDAPControl		**ctrls = NULL;
+
+	/*
+	 * Rewrite the modify dn, if needed
+	 */
+	dc.op = op;
+	dc.target = mt;
+	dc.memctx = op->o_tmpmemctx;
+	dc.to_from = MASSAGE_REQ;
+
+	asyncmeta_dn_massage( &dc, &op->o_req_dn, &mdn );
+
+	for ( i = 0, ml = op->orm_modlist; ml; i++ ,ml = ml->sml_next )
+		;
+	if (i > 0) {
+		mods = op->o_tmpalloc( sizeof( LDAPMod )*i, op->o_tmpmemctx );
+	}
+
+	if ( mods == NULL ) {
+		rs->sr_err = LDAP_OTHER;
+		retcode = META_SEARCH_ERR;
+		goto doreturn;
+	}
+	modv = ( LDAPMod ** )op->o_tmpalloc( ( i + 1 )*sizeof( LDAPMod * ), op->o_tmpmemctx );
+	if ( modv == NULL ) {
+		rs->sr_err = LDAP_OTHER;
+		retcode = META_SEARCH_ERR;
+		goto doreturn;
+	}
+
+	isupdate = be_shadow_update( op );
+	for ( i = 0, ml = op->orm_modlist; ml; ml = ml->sml_next ) {
+		int	j;
+
+		if ( !isupdate && !get_relax( op ) && ml->sml_desc->ad_type->sat_no_user_mod  )
+		{
+			continue;
+		}
+
+		modv[ i ] = &mods[ i ];
+		mods[ i ].mod_op = ml->sml_op | LDAP_MOD_BVALUES;
+		mods[ i ].mod_type = ml->sml_desc->ad_cname.bv_val;
+
+		if ( ml->sml_values != NULL ) {
+			j = ml->sml_numvals;
+			mods[ i ].mod_bvalues =(struct berval **)op->o_tmpalloc( ( j + 1 ) *sizeof( struct berval * ), op->o_tmpmemctx );
+			for ( j = 0; !BER_BVISNULL( &ml->sml_values[ j ] ); j++ ) {
+				mods[ i ].mod_bvalues[ j ] = op->o_tmpalloc(sizeof( struct berval ), op->o_tmpmemctx );
+				if ( ml->sml_desc->ad_type->sat_syntax == slap_schema.si_syn_distinguishedName )
+					asyncmeta_dn_massage( &dc, &ml->sml_values[ j ], mods[ i ].mod_bvalues[ j ] );
+				else
+					*mods[ i ].mod_bvalues[ j ] = ml->sml_values[ j ];
+			}
+			mods[ i ].mod_bvalues[ j ] = NULL;
+
+		} else {
+			mods[ i ].mod_bvalues = NULL;
+		}
+
+		i++;
+	}
+	modv[ i ] = 0;
+
+	asyncmeta_set_msc_time(msc);
+	ctrls = op->o_ctrls;
+	if ( asyncmeta_controls_add( op, rs, mc, candidate, bc->is_root, &ctrls) != LDAP_SUCCESS )
+	{
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		retcode = META_SEARCH_ERR;
+		goto done;
+	}
+
+	/* someone reset the connection */
+	if (!( LDAP_BACK_CONN_ISBOUND( msc )
+	       || LDAP_BACK_CONN_ISANON( msc )) || msc->msc_ld == NULL ) {
+		Debug( asyncmeta_debug , "msc %p not initialized at %s:%d\n", msc, __FILE__, __LINE__ );
+		goto error_unavailable;
+	}
+
+	ber = ldap_build_modify_req( msc->msc_ld, mdn.bv_val, modv, ctrls, NULL, &msgid);
+
+	if (!ber) {
+		Debug( asyncmeta_debug, "%s asyncmeta_back_modify_start: Operation encoding failed with errno %d\n",
+		       op->o_log_prefix, msc->msc_ld->ld_errno );
+		rs->sr_err = LDAP_OPERATIONS_ERROR;
+		rs->sr_text = "Failed to encode proxied request";
+		retcode = META_SEARCH_ERR;
+		goto done;
+	}
+
+	if (ber) {
+		struct timeval tv = {0, mt->mt_network_timeout*1000};
+		ber_socket_t s;
+		if (!( LDAP_BACK_CONN_ISBOUND( msc )
+		       || LDAP_BACK_CONN_ISANON( msc )) || msc->msc_ld == NULL ) {
+			Debug( asyncmeta_debug, "msc %p not initialized at %s:%d\n", msc, __FILE__, __LINE__ );
+			goto error_unavailable;
+		}
+
+		ldap_get_option( msc->msc_ld, LDAP_OPT_DESC, &s );
+		if (s < 0) {
+			Debug( asyncmeta_debug, "msc %p not initialized at %s:%d\n", msc, __FILE__, __LINE__ );
+			goto error_unavailable;
+		}
+
+		rc = ldap_int_poll( msc->msc_ld, s, &tv, 1);
+		if (rc < 0) {
+			Debug( asyncmeta_debug, "msc %p not writable within network timeout %s:%d\n", msc, __FILE__, __LINE__ );
+			if ((msc->msc_result_time + META_BACK_RESULT_INTERVAL) < slap_get_time()) {
+				rc = LDAP_SERVER_DOWN;
+			} else {
+				goto error_unavailable;
+			}
+		} else {
+			candidates[ candidate ].sr_msgid = msgid;
+			rc = ldap_send_initial_request( msc->msc_ld, LDAP_REQ_MODIFY,
+							mdn.bv_val, ber, msgid );
+			if (rc == msgid)
+				rc = LDAP_SUCCESS;
+			else
+				rc = LDAP_SERVER_DOWN;
+			ber = NULL;
+		}
+
+		switch ( rc ) {
+		case LDAP_SUCCESS:
+			retcode = META_SEARCH_CANDIDATE;
+			asyncmeta_set_msc_time(msc);
+			goto done;
+
+		case LDAP_SERVER_DOWN:
+			/* do not lock if called from asyncmeta_handle_bind_result. Also do not reset the connection */
+			if (do_lock > 0) {
+				ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+				asyncmeta_reset_msc(NULL, mc, candidate, 0, __FUNCTION__);
+				ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			}
+			/* fall though*/
+		default:
+			Debug( asyncmeta_debug, "msc %p ldap_send_initial_request failed. %s:%d\n", msc, __FILE__, __LINE__ );
+			goto error_unavailable;
+		}
+	}
+
+error_unavailable:
+	if (ber)
+		ber_free(ber, 1);
+	switch (bc->nretries[candidate]) {
+	case -1: /* nretries = forever */
+		ldap_pvt_thread_yield();
+		retcode = META_SEARCH_NEED_BIND;
+		break;
+	case 0: /* no retries left */
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		rs->sr_err = LDAP_UNAVAILABLE;
+		rs->sr_text = "Unable to send modify request to target";
+		retcode = META_SEARCH_ERR;
+		break;
+	default: /* more retries left - try to rebind and go again */
+		retcode = META_SEARCH_NEED_BIND;
+		bc->nretries[candidate]--;
+		ldap_pvt_thread_yield();
+		break;
+	}
+done:
+	(void)mi->mi_ldap_extra->controls_free( op, rs, &ctrls );
+
+	if ( mdn.bv_val != op->o_req_dn.bv_val ) {
+		op->o_tmpfree( mdn.bv_val, op->o_tmpmemctx );
+	}
+
+doreturn:;
+	Debug( LDAP_DEBUG_TRACE, "%s <<< asyncmeta_back_modify_start[%p]=%d\n", op->o_log_prefix, msc, candidates[candidate].sr_msgid );
+	return retcode;
+}
+
+int
+asyncmeta_back_modify( Operation *op, SlapReply *rs )
+{
+	a_metainfo_t	*mi = ( a_metainfo_t * )op->o_bd->be_private;
+	a_metatarget_t	*mt;
+	a_metaconn_t	*mc;
+	int		rc, candidate = -1;
+	void *thrctx = op->o_threadctx;
+	bm_context_t *bc;
+	SlapReply *candidates;
+	time_t current_time = slap_get_time();
+	int max_pending_ops = (mi->mi_max_pending_ops == 0) ? META_BACK_CFG_MAX_PENDING_OPS : mi->mi_max_pending_ops;
+
+	Debug(LDAP_DEBUG_ARGS, "==> asyncmeta_back_modify: %s\n",
+	      op->o_req_dn.bv_val );
+
+	if (current_time > op->o_time) {
+		Debug(asyncmeta_debug, "==> asyncmeta_back_modify[%s]: o_time:[%ld], current time: [%ld]\n",
+		      op->o_log_prefix, op->o_time, current_time );
+	}
+
+	asyncmeta_new_bm_context(op, rs, &bc, mi->mi_ntargets, mi );
+	if (bc == NULL) {
+		rs->sr_err = LDAP_OTHER;
+		send_ldap_result(op, rs);
+		return rs->sr_err;
+	}
+
+	candidates = bc->candidates;
+	mc = asyncmeta_getconn( op, rs, candidates, &candidate, LDAP_BACK_DONTSEND, 0);
+	if ( !mc || rs->sr_err != LDAP_SUCCESS) {
+		send_ldap_result(op, rs);
+		return rs->sr_err;
+	}
+
+	mt = mi->mi_targets[ candidate ];
+	bc->timeout = mt->mt_timeout[ SLAP_OP_MODIFY ];
+	bc->retrying = LDAP_BACK_RETRYING;
+	bc->sendok = ( LDAP_BACK_SENDRESULT | bc->retrying );
+	bc->stoptime = op->o_time + bc->timeout;
+	bc->bc_active = 1;
+
+	if (mc->pending_ops >= max_pending_ops) {
+		rs->sr_err = LDAP_BUSY;
+		rs->sr_text = "Maximum pending ops limit exceeded";
+		send_ldap_result(op, rs);
+		return rs->sr_err;
+	}
+
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	rc = asyncmeta_add_message_queue(mc, bc);
+	mc->mc_conns[candidate].msc_active++;
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+
+	if (rc != LDAP_SUCCESS) {
+		rs->sr_err = LDAP_BUSY;
+		rs->sr_text = "Maximum pending ops limit exceeded";
+		send_ldap_result(op, rs);
+		ldap_pvt_thread_mutex_lock(&mc->mc_om_mutex);
+		mc->mc_conns[candidate].msc_active--;
+		ldap_pvt_thread_mutex_unlock(&mc->mc_om_mutex);
+		goto finish;
+	}
+
+retry:
+	if (bc->timeout && bc->stoptime < slap_get_time()) {
+		int		timeout_err;
+		timeout_err = op->o_protocol >= LDAP_VERSION3 ?
+			LDAP_ADMINLIMIT_EXCEEDED : LDAP_OTHER;
+		rs->sr_err = timeout_err;
+		rs->sr_text = "Operation timed out before it was sent to target";
+		asyncmeta_error_cleanup(op, rs, bc, mc, candidate);
+		goto finish;
+	}
+
+	rc = asyncmeta_dobind_init_with_retry(op, rs, bc, mc, candidate);
+	switch (rc)
+	{
+	case META_SEARCH_CANDIDATE:
+		/* target is already bound, just send the request */
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_modify:  "
+		       "cnd=\"%d\"\n", op->o_log_prefix, candidate );
+
+		rc = asyncmeta_back_modify_start( op, rs, mc, bc, candidate, 1);
+		if (rc == META_SEARCH_ERR) {
+			asyncmeta_error_cleanup(op, rs, bc, mc, candidate);
+			goto finish;
+
+		} else if (rc == META_SEARCH_NEED_BIND) {
+			goto retry;
+		}
+		break;
+	case META_SEARCH_NOT_CANDIDATE:
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_modify: NOT_CANDIDATE "
+		       "cnd=\"%d\"\n", op->o_log_prefix, candidate );
+		asyncmeta_error_cleanup(op, rs, bc, mc, candidate);
+		goto finish;
+
+	case META_SEARCH_NEED_BIND:
+	case META_SEARCH_BINDING:
+			Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_modify: BINDING "
+			       "cnd=\"%d\" %p\n", op->o_log_prefix, candidate , &mc->mc_conns[candidate]);
+			/* Todo add the context to the message queue but do not send the request
+			   the receiver must send this when we are done binding */
+			break;
+
+	case META_SEARCH_ERR:
+			Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_modify: ERR "
+			       "cnd=\"%d\"\n", op->o_log_prefix, candidate );
+			asyncmeta_error_cleanup(op, rs, bc, mc, candidate);
+			goto finish;
+		default:
+			assert( 0 );
+			break;
+		}
+
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	mc->mc_conns[candidate].msc_active--;
+	asyncmeta_start_one_listener(mc, candidates, bc, candidate);
+	bc->bc_active--;
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+	rs->sr_err = SLAPD_ASYNCOP;
+
+finish:
+	return rs->sr_err;
+}
diff --git a/servers/slapd/back-asyncmeta/modrdn.c b/servers/slapd/back-asyncmeta/modrdn.c
new file mode 100644
index 0000000..03dee11
--- /dev/null
+++ b/servers/slapd/back-asyncmeta/modrdn.c
@@ -0,0 +1,367 @@
+/* modrdn.c - modrdn request handler for back-syncmeta */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016-2022 The OpenLDAP Foundation.
+ * Portions Copyright 2016 Symas Corporation.
+ * 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 developed by Symas Corporation
+ * based on back-meta module for inclusion in OpenLDAP Software.
+ * This work was sponsored by Ericsson. */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/socket.h>
+#include <ac/string.h>
+#include "slap.h"
+#include "../../../libraries/liblber/lber-int.h"
+#include "../../../libraries/libldap/ldap-int.h"
+#include "../back-ldap/back-ldap.h"
+#include "back-asyncmeta.h"
+
+meta_search_candidate_t
+asyncmeta_back_modrdn_start(Operation *op,
+			    SlapReply *rs,
+			    a_metaconn_t *mc,
+			    bm_context_t *bc,
+			    int candidate,
+			    int do_lock)
+{
+	a_dncookie	dc;
+	a_metainfo_t	*mi = mc->mc_info;
+	a_metatarget_t	*mt = mi->mi_targets[ candidate ];
+	struct berval	mdn = BER_BVNULL,
+		mnewSuperior = BER_BVNULL,
+		newrdn = BER_BVNULL;
+	int rc = 0;
+	LDAPControl	**ctrls = NULL;
+	meta_search_candidate_t retcode = META_SEARCH_CANDIDATE;
+	BerElement *ber = NULL;
+	a_metasingleconn_t	*msc = &mc->mc_conns[ candidate ];
+	SlapReply		*candidates = bc->candidates;
+	ber_int_t	msgid;
+
+	dc.op = op;
+	dc.target = mt;
+	dc.memctx = op->o_tmpmemctx;
+	dc.to_from = MASSAGE_REQ;
+
+	if ( op->orr_newSup ) {
+
+		/*
+		 * NOTE: the newParent, if defined, must be on the
+		 * same target as the entry to be renamed.  This check
+		 * has been anticipated in meta_back_getconn()
+		 */
+		/*
+		 * FIXME: one possibility is to delete the entry
+		 * from one target and add it to the other;
+		 * unfortunately we'd need write access to both,
+		 * which is nearly impossible; for administration
+		 * needs, the rootdn of the metadirectory could
+		 * be mapped to an administrative account on each
+		 * target (the binddn?); we'll see.
+		 */
+		/*
+		 * NOTE: we need to port the identity assertion
+		 * feature from back-ldap
+		 */
+
+		/* needs LDAPv3 */
+		switch ( mt->mt_version ) {
+		case LDAP_VERSION3:
+			break;
+
+		case 0:
+			if ( op->o_protocol == 0 || op->o_protocol == LDAP_VERSION3 ) {
+				break;
+			}
+			/* fall thru */
+
+		default:
+			/* op->o_protocol cannot be anything but LDAPv3,
+			 * otherwise wouldn't be here */
+			rs->sr_err = LDAP_UNWILLING_TO_PERFORM;
+			retcode = META_SEARCH_ERR;
+			goto done;
+		}
+
+		/*
+		 * Rewrite the new superior, if defined and required
+		 */
+		asyncmeta_dn_massage( &dc, op->orr_newSup, &mnewSuperior );
+	}
+
+	/*
+	 * Rewrite the modrdn dn, if required
+	 */
+	asyncmeta_dn_massage( &dc, &op->o_req_dn, &mdn );
+
+	/* NOTE: we need to copy the newRDN in case it was formed
+	 * from a DN by simply changing the length (ITS#5397) */
+	newrdn = op->orr_newrdn;
+	if ( newrdn.bv_val[ newrdn.bv_len ] != '\0' ) {
+		ber_dupbv_x( &newrdn, &op->orr_newrdn, op->o_tmpmemctx );
+	}
+
+	asyncmeta_set_msc_time(msc);
+	ctrls = op->o_ctrls;
+	if ( asyncmeta_controls_add( op, rs, mc, candidate, bc->is_root, &ctrls ) != LDAP_SUCCESS )
+	{
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		retcode = META_SEARCH_ERR;
+		goto done;
+	}
+	/* someone might have reset the connection */
+	if (!( LDAP_BACK_CONN_ISBOUND( msc )
+	       || LDAP_BACK_CONN_ISANON( msc )) || msc->msc_ld == NULL ) {
+		Debug( asyncmeta_debug, "msc %p not initialized at %s:%d\n", msc, __FILE__, __LINE__ );
+		goto error_unavailable;
+	}
+	ber = ldap_build_moddn_req( msc->msc_ld, mdn.bv_val, newrdn.bv_val,
+			mnewSuperior.bv_val, op->orr_deleteoldrdn, ctrls, NULL, &msgid);
+
+	if (!ber) {
+		Debug( asyncmeta_debug, "%s asyncmeta_back_modrdn_start: Operation encoding failed with errno %d\n",
+		       op->o_log_prefix, msc->msc_ld->ld_errno );
+		rs->sr_err = LDAP_OPERATIONS_ERROR;
+		rs->sr_text = "Failed to encode proxied request";
+		retcode = META_SEARCH_ERR;
+		goto done;
+	}
+
+	if (ber) {
+		struct timeval tv = {0, mt->mt_network_timeout*1000};
+		ber_socket_t s;
+
+		if (!( LDAP_BACK_CONN_ISBOUND( msc )
+		       || LDAP_BACK_CONN_ISANON( msc )) || msc->msc_ld == NULL ) {
+			Debug( asyncmeta_debug, "msc %p not initialized at %s:%d\n", msc, __FILE__, __LINE__ );
+			goto error_unavailable;
+		}
+
+		ldap_get_option( msc->msc_ld, LDAP_OPT_DESC, &s );
+		if (s < 0) {
+			Debug( asyncmeta_debug, "msc %p not initialized at %s:%d\n", msc, __FILE__, __LINE__ );
+			goto error_unavailable;
+		}
+
+		rc = ldap_int_poll( msc->msc_ld, s, &tv, 1);
+		if (rc < 0) {
+			Debug( asyncmeta_debug, "msc %p not writable within network timeout %s:%d\n", msc, __FILE__, __LINE__ );
+			if ((msc->msc_result_time + META_BACK_RESULT_INTERVAL) < slap_get_time()) {
+				rc = LDAP_SERVER_DOWN;
+			} else {
+				goto error_unavailable;
+			}
+		} else {
+			candidates[ candidate ].sr_msgid = msgid;
+			rc = ldap_send_initial_request( msc->msc_ld, LDAP_REQ_MODRDN,
+							mdn.bv_val, ber, msgid );
+			if (rc == msgid)
+				rc = LDAP_SUCCESS;
+			else
+				rc = LDAP_SERVER_DOWN;
+			ber = NULL;
+		}
+
+		switch ( rc ) {
+		case LDAP_SUCCESS:
+			retcode = META_SEARCH_CANDIDATE;
+			asyncmeta_set_msc_time(msc);
+			goto done;
+
+		case LDAP_SERVER_DOWN:
+			/* do not lock if called from asyncmeta_handle_bind_result. Also do not reset the connection */
+			if (do_lock > 0) {
+				ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+				asyncmeta_reset_msc(NULL, mc, candidate, 0, __FUNCTION__ );
+				ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			}
+			/* fall though*/
+		default:
+			Debug( asyncmeta_debug, "msc %p ldap_send_initial_request failed. %s:%d\n", msc, __FILE__, __LINE__ );
+			goto error_unavailable;
+		}
+	}
+
+error_unavailable:
+	if (ber)
+		ber_free(ber, 1);
+	switch (bc->nretries[candidate]) {
+	case -1: /* nretries = forever */
+		retcode = META_SEARCH_NEED_BIND;
+		ldap_pvt_thread_yield();
+		break;
+	case 0: /* no retries left */
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		rs->sr_err = LDAP_UNAVAILABLE;
+		rs->sr_text = "Unable to send modrdn request to target";
+		retcode = META_SEARCH_ERR;
+		break;
+	default: /* more retries left - try to rebind and go again */
+		retcode = META_SEARCH_NEED_BIND;
+		bc->nretries[candidate]--;
+		ldap_pvt_thread_yield();
+		break;
+	}
+done:
+	(void)mi->mi_ldap_extra->controls_free( op, rs, &ctrls );
+
+	if ( mdn.bv_val != op->o_req_dn.bv_val ) {
+		op->o_tmpfree( mdn.bv_val, op->o_tmpmemctx );
+	}
+
+	if ( !BER_BVISNULL( &mnewSuperior )
+			&& mnewSuperior.bv_val != op->orr_newSup->bv_val )
+	{
+		op->o_tmpfree( mnewSuperior.bv_val, op->o_tmpmemctx );
+	}
+
+	if ( newrdn.bv_val != op->orr_newrdn.bv_val ) {
+		op->o_tmpfree( newrdn.bv_val, op->o_tmpmemctx );
+	}
+
+	Debug( LDAP_DEBUG_TRACE, "%s <<< asyncmeta_back_modrdn_start[%p]=%d\n", op->o_log_prefix, msc, candidates[candidate].sr_msgid );
+	return retcode;
+}
+
+int
+asyncmeta_back_modrdn( Operation *op, SlapReply *rs )
+{
+	a_metainfo_t	*mi = ( a_metainfo_t * )op->o_bd->be_private;
+	a_metatarget_t	*mt;
+	a_metaconn_t	*mc;
+	int		rc, candidate = -1;
+	void *thrctx = op->o_threadctx;
+	bm_context_t *bc;
+	SlapReply *candidates;
+	time_t current_time = slap_get_time();
+	int max_pending_ops = (mi->mi_max_pending_ops == 0) ? META_BACK_CFG_MAX_PENDING_OPS : mi->mi_max_pending_ops;
+
+	Debug(LDAP_DEBUG_ARGS, "==> asyncmeta_back_modrdn: %s\n",
+	      op->o_req_dn.bv_val );
+
+	if (current_time > op->o_time) {
+		Debug(asyncmeta_debug, "==> asyncmeta_back_modrdn[%s]: o_time:[%ld], current time: [%ld]\n",
+		      op->o_log_prefix, op->o_time, current_time );
+	}
+	asyncmeta_new_bm_context(op, rs, &bc, mi->mi_ntargets, mi );
+	if (bc == NULL) {
+		rs->sr_err = LDAP_OTHER;
+		send_ldap_result(op, rs);
+		return rs->sr_err;
+	}
+
+	candidates = bc->candidates;
+	mc = asyncmeta_getconn( op, rs, candidates, &candidate, LDAP_BACK_DONTSEND, 0);
+	if ( !mc || rs->sr_err != LDAP_SUCCESS) {
+		send_ldap_result(op, rs);
+		return rs->sr_err;
+	}
+
+	mt = mi->mi_targets[ candidate ];
+	bc->timeout = mt->mt_timeout[ SLAP_OP_MODRDN ];
+	bc->retrying = LDAP_BACK_RETRYING;
+	bc->sendok = ( LDAP_BACK_SENDRESULT | bc->retrying );
+	bc->stoptime = op->o_time + bc->timeout;
+	bc->bc_active = 1;
+
+	if (mc->pending_ops >= max_pending_ops) {
+		rs->sr_err = LDAP_BUSY;
+		rs->sr_text = "Maximum pending ops limit exceeded";
+		send_ldap_result(op, rs);
+		return rs->sr_err;
+	}
+
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	rc = asyncmeta_add_message_queue(mc, bc);
+	mc->mc_conns[candidate].msc_active++;
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+
+	if (rc != LDAP_SUCCESS) {
+		rs->sr_err = LDAP_BUSY;
+		rs->sr_text = "Maximum pending ops limit exceeded";
+		send_ldap_result(op, rs);
+		ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+		mc->mc_conns[candidate].msc_active--;
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+		goto finish;
+	}
+
+retry:
+	if (bc->timeout && bc->stoptime < slap_get_time()) {
+		int		timeout_err;
+		timeout_err = op->o_protocol >= LDAP_VERSION3 ?
+			LDAP_ADMINLIMIT_EXCEEDED : LDAP_OTHER;
+		rs->sr_err = timeout_err;
+		rs->sr_text = "Operation timed out before it was sent to target";
+		asyncmeta_error_cleanup(op, rs, bc, mc, candidate);
+		goto finish;
+
+	}
+
+	rc = asyncmeta_dobind_init_with_retry(op, rs, bc, mc, candidate);
+	switch (rc)
+	{
+	case META_SEARCH_CANDIDATE:
+		/* target is already bound, just send the request */
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_modrdn:  "
+		       "cnd=\"%d\"\n", op->o_log_prefix, candidate );
+
+		rc = asyncmeta_back_modrdn_start( op, rs, mc, bc, candidate, 1);
+		if (rc == META_SEARCH_ERR) {
+			asyncmeta_error_cleanup(op, rs, bc, mc, candidate);
+			goto finish;
+
+		} else if (rc == META_SEARCH_NEED_BIND) {
+			goto retry;
+		}
+		break;
+	case META_SEARCH_NOT_CANDIDATE:
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_modrdn: NOT_CANDIDATE "
+		       "cnd=\"%d\"\n", op->o_log_prefix, candidate );
+		asyncmeta_error_cleanup(op, rs, bc, mc, candidate);
+		goto finish;
+
+	case META_SEARCH_NEED_BIND:
+	case META_SEARCH_BINDING:
+			Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_modrdn: BINDING "
+			       "cnd=\"%d\" %p\n", op->o_log_prefix, candidate , &mc->mc_conns[candidate]);
+			/* Todo add the context to the message queue but do not send the request
+			   the receiver must send this when we are done binding */
+			/* question - how would do receiver know to which targets??? */
+			break;
+
+	case META_SEARCH_ERR:
+			Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_modrdn: ERR "
+			       "cnd=\"%d\"\n", op->o_log_prefix, candidate );
+			asyncmeta_error_cleanup(op, rs, bc, mc, candidate);
+			goto finish;
+		default:
+			assert( 0 );
+			break;
+		}
+
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	mc->mc_conns[candidate].msc_active--;
+	asyncmeta_start_one_listener(mc, candidates, bc, candidate);
+	bc->bc_active--;
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+	rs->sr_err = SLAPD_ASYNCOP;
+finish:
+	return rs->sr_err;
+}
diff --git a/servers/slapd/back-asyncmeta/proto-asyncmeta.h b/servers/slapd/back-asyncmeta/proto-asyncmeta.h
new file mode 100644
index 0000000..54041fa
--- /dev/null
+++ b/servers/slapd/back-asyncmeta/proto-asyncmeta.h
@@ -0,0 +1,53 @@
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016-2022 The OpenLDAP Foundation.
+ * Portions Copyright 2016 Symas Corporation.
+ * 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 developed by Symas Corporation
+ * based on back-meta module for inclusion in OpenLDAP Software.
+ * This work was sponsored by Ericsson. */
+
+#ifndef PROTO_ASYNCMETA_H
+#define PROTO_ASYNCMETA_H
+
+LDAP_BEGIN_DECL
+
+extern BI_init			asyncmeta_back_initialize;
+
+extern BI_open			asyncmeta_back_open;
+extern BI_close			asyncmeta_back_close;
+extern BI_destroy		asyncmeta_back_destroy;
+
+extern BI_db_init		asyncmeta_back_db_init;
+extern BI_db_open		asyncmeta_back_db_open;
+extern BI_db_destroy		asyncmeta_back_db_destroy;
+extern BI_db_close		asyncmeta_back_db_close;
+extern BI_db_config		asyncmeta_back_db_config;
+
+extern BI_op_bind		asyncmeta_back_bind;
+extern BI_op_search		asyncmeta_back_search;
+extern BI_op_compare		asyncmeta_back_compare;
+extern BI_op_modify		asyncmeta_back_modify;
+extern BI_op_modrdn		asyncmeta_back_modrdn;
+extern BI_op_add		asyncmeta_back_add;
+extern BI_op_delete		asyncmeta_back_delete;
+
+extern BI_connection_destroy	asyncmeta_back_conn_destroy;
+
+int asyncmeta_back_init_cf( BackendInfo *bi );
+
+LDAP_END_DECL
+
+#endif /* PROTO_ASYNCMETA_H */
diff --git a/servers/slapd/back-asyncmeta/search.c b/servers/slapd/back-asyncmeta/search.c
new file mode 100644
index 0000000..0b0db82
--- /dev/null
+++ b/servers/slapd/back-asyncmeta/search.c
@@ -0,0 +1,963 @@
+/* search.c - search request handler for back-asyncmeta */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016-2022 The OpenLDAP Foundation.
+ * Portions Copyright 2016 Symas Corporation.
+ * 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 developed by Symas Corporation
+ * based on back-meta module for inclusion in OpenLDAP Software.
+ * This work was sponsored by Ericsson. */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/socket.h>
+#include <ac/string.h>
+#include <ac/time.h>
+#include "slap.h"
+#include "../../../libraries/liblber/lber-int.h"
+#include "../../../libraries/libldap/ldap-int.h"
+#include "lutil.h"
+#include "../back-ldap/back-ldap.h"
+#include "back-asyncmeta.h"
+
+static void
+asyncmeta_handle_onerr_stop(Operation *op,
+			    SlapReply *rs,
+			    a_metaconn_t *mc,
+			    bm_context_t *bc,
+			    int candidate)
+{
+	a_metainfo_t *mi = mc->mc_info;
+	int j;
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	if (asyncmeta_bc_in_queue(mc,bc) == NULL || bc->bc_active > 1) {
+		bc->bc_active--;
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+		return;
+	}
+	asyncmeta_drop_bc(mc, bc);
+	for (j=0; j<mi->mi_ntargets; j++) {
+		if (j != candidate && bc->candidates[j].sr_msgid >= 0
+		    && mc->mc_conns[j].msc_ld != NULL && !META_BACK_CONN_CREATING( &mc->mc_conns[j] )) {
+			asyncmeta_back_cancel( mc, op,
+						bc->candidates[ j ].sr_msgid, j );
+		}
+	}
+	slap_sl_mem_setctx(op->o_threadctx, op->o_tmpmemctx);
+	operation_counter_init( op, op->o_threadctx );
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+	send_ldap_result(op, rs);
+}
+
+static int
+asyncmeta_int_filter2bv( a_dncookie		*dc,
+			 Filter			*f,
+			 struct berval	*fstr )
+{
+	int		i;
+	Filter		*p;
+	struct berval	atmp,
+			vtmp,
+			ntmp,
+			*tmp;
+	static struct berval
+			/* better than nothing... */
+			ber_bvfalse = BER_BVC( "(!(objectClass=*))" ),
+			ber_bvtf_false = BER_BVC( "(|)" ),
+			/* better than nothing... */
+			ber_bvtrue = BER_BVC( "(objectClass=*)" ),
+			ber_bvtf_true = BER_BVC( "(&)" ),
+			ber_bverror = BER_BVC( "(?=error)" ),
+			ber_bvunknown = BER_BVC( "(?=unknown)" ),
+			ber_bvnone = BER_BVC( "(?=none)" );
+	ber_len_t	len;
+	void *memctx = dc->memctx;
+
+	assert( fstr != NULL );
+	BER_BVZERO( fstr );
+
+	if ( f == NULL ) {
+		ber_dupbv_x( fstr, &ber_bvnone, memctx );
+		return LDAP_OTHER;
+	}
+
+	switch ( ( f->f_choice & SLAPD_FILTER_MASK ) ) {
+	case LDAP_FILTER_EQUALITY:
+		if ( f->f_av_desc->ad_type->sat_syntax == slap_schema.si_syn_distinguishedName ) {
+			asyncmeta_dn_massage( dc, &f->f_av_value, &vtmp );
+		} else {
+			vtmp = f->f_av_value;
+		}
+
+		filter_escape_value_x( &vtmp, &ntmp, memctx );
+		fstr->bv_len = f->f_av_desc->ad_cname.bv_len + ntmp.bv_len
+			+ ( sizeof("(=)") - 1 );
+		fstr->bv_val = dc->op->o_tmpalloc( fstr->bv_len + 1, memctx );
+
+		snprintf( fstr->bv_val, fstr->bv_len + 1, "(%s=%s)",
+			f->f_av_desc->ad_cname.bv_val, ntmp.bv_len ? ntmp.bv_val : "" );
+
+		ber_memfree_x( ntmp.bv_val, memctx );
+		break;
+
+	case LDAP_FILTER_GE:
+		filter_escape_value_x( &f->f_av_value, &ntmp, memctx );
+		fstr->bv_len = f->f_av_desc->ad_cname.bv_len + ntmp.bv_len
+			+ ( sizeof("(>=)") - 1 );
+		fstr->bv_val = dc->op->o_tmpalloc( fstr->bv_len + 1, memctx );
+
+		snprintf( fstr->bv_val, fstr->bv_len + 1, "(%s>=%s)",
+			f->f_av_desc->ad_cname.bv_val, ntmp.bv_len ? ntmp.bv_val : "" );
+
+		ber_memfree_x( ntmp.bv_val, memctx );
+		break;
+
+	case LDAP_FILTER_LE:
+		filter_escape_value_x( &f->f_av_value, &ntmp, memctx );
+		fstr->bv_len = f->f_av_desc->ad_cname.bv_len + ntmp.bv_len
+			+ ( sizeof("(<=)") - 1 );
+		fstr->bv_val = dc->op->o_tmpalloc( fstr->bv_len + 1, memctx );
+
+		snprintf( fstr->bv_val, fstr->bv_len + 1, "(%s<=%s)",
+			f->f_av_desc->ad_cname.bv_val,  ntmp.bv_len ? ntmp.bv_val : "" );
+
+		ber_memfree_x( ntmp.bv_val, memctx );
+		break;
+
+	case LDAP_FILTER_APPROX:
+		filter_escape_value_x( &f->f_av_value, &ntmp, memctx );
+		fstr->bv_len = f->f_av_desc->ad_cname.bv_len + ntmp.bv_len
+			+ ( sizeof("(~=)") - 1 );
+		fstr->bv_val = dc->op->o_tmpalloc( fstr->bv_len + 1, memctx );
+
+		snprintf( fstr->bv_val, fstr->bv_len + 1, "(%s~=%s)",
+			f->f_av_desc->ad_cname.bv_val,  ntmp.bv_len ? ntmp.bv_val : "" );
+
+		ber_memfree_x( ntmp.bv_val, memctx );
+		break;
+
+	case LDAP_FILTER_SUBSTRINGS:
+		fstr->bv_len = f->f_sub_desc->ad_cname.bv_len + ( STRLENOF( "(=*)" ) );
+		fstr->bv_val = dc->op->o_tmpalloc( fstr->bv_len + 128, memctx ); /* FIXME: why 128 ? */
+
+		snprintf( fstr->bv_val, fstr->bv_len + 1, "(%s=*)",
+			f->f_sub_desc->ad_cname.bv_val );
+
+		if ( !BER_BVISNULL( &f->f_sub_initial ) ) {
+			len = fstr->bv_len;
+
+			filter_escape_value_x( &f->f_sub_initial, &ntmp, memctx );
+
+			fstr->bv_len += ntmp.bv_len;
+			fstr->bv_val = dc->op->o_tmprealloc( fstr->bv_val, fstr->bv_len + 1, memctx );
+
+			snprintf( &fstr->bv_val[len - 2], ntmp.bv_len + 3,
+				/* "(attr=" */ "%s*)",
+				ntmp.bv_len ? ntmp.bv_val : "" );
+
+			ber_memfree_x( ntmp.bv_val, memctx );
+		}
+
+		if ( f->f_sub_any != NULL ) {
+			for ( i = 0; !BER_BVISNULL( &f->f_sub_any[i] ); i++ ) {
+				len = fstr->bv_len;
+				filter_escape_value_x( &f->f_sub_any[i], &ntmp, memctx );
+
+				fstr->bv_len += ntmp.bv_len + 1;
+				fstr->bv_val = dc->op->o_tmprealloc( fstr->bv_val, fstr->bv_len + 1, memctx );
+
+				snprintf( &fstr->bv_val[len - 1], ntmp.bv_len + 3,
+					/* "(attr=[init]*[any*]" */ "%s*)",
+					ntmp.bv_len ? ntmp.bv_val : "" );
+				ber_memfree_x( ntmp.bv_val, memctx );
+			}
+		}
+
+		if ( !BER_BVISNULL( &f->f_sub_final ) ) {
+			len = fstr->bv_len;
+
+			filter_escape_value_x( &f->f_sub_final, &ntmp, memctx );
+
+			fstr->bv_len += ntmp.bv_len;
+			fstr->bv_val = dc->op->o_tmprealloc( fstr->bv_val, fstr->bv_len + 1, memctx );
+
+			snprintf( &fstr->bv_val[len - 1], ntmp.bv_len + 3,
+				/* "(attr=[init*][any*]" */ "%s)",
+				ntmp.bv_len ? ntmp.bv_val : "" );
+
+			ber_memfree_x( ntmp.bv_val, memctx );
+		}
+
+		break;
+
+	case LDAP_FILTER_PRESENT:
+		fstr->bv_len = f->f_desc->ad_cname.bv_len + ( STRLENOF( "(=*)" ) );
+		fstr->bv_val = dc->op->o_tmpalloc( fstr->bv_len + 1, memctx );
+
+		snprintf( fstr->bv_val, fstr->bv_len + 1, "(%s=*)",
+			f->f_desc->ad_cname.bv_val );
+		break;
+
+	case LDAP_FILTER_AND:
+	case LDAP_FILTER_OR:
+	case LDAP_FILTER_NOT:
+		fstr->bv_len = STRLENOF( "(%)" );
+		fstr->bv_val = dc->op->o_tmpalloc( fstr->bv_len + 128, memctx );	/* FIXME: why 128? */
+
+		snprintf( fstr->bv_val, fstr->bv_len + 1, "(%c)",
+			f->f_choice == LDAP_FILTER_AND ? '&' :
+			f->f_choice == LDAP_FILTER_OR ? '|' : '!' );
+
+		for ( p = f->f_list; p != NULL; p = p->f_next ) {
+			int	rc;
+
+			len = fstr->bv_len;
+
+			rc = asyncmeta_int_filter2bv( dc, p, &vtmp );
+			if ( rc != LDAP_SUCCESS ) {
+				return rc;
+			}
+
+			fstr->bv_len += vtmp.bv_len;
+			fstr->bv_val = dc->op->o_tmprealloc( fstr->bv_val, fstr->bv_len + 1, memctx );
+
+			snprintf( &fstr->bv_val[len-1], vtmp.bv_len + 2,
+				/*"("*/ "%s)", vtmp.bv_len ? vtmp.bv_val : "" );
+
+			ber_memfree_x( vtmp.bv_val, memctx );
+		}
+
+		break;
+
+	case LDAP_FILTER_EXT:
+		if ( f->f_mr_desc ) {
+			atmp = f->f_mr_desc->ad_cname;
+
+		} else {
+			BER_BVSTR( &atmp, "" );
+		}
+		filter_escape_value_x( &f->f_mr_value, &ntmp, memctx );
+
+		/* FIXME: cleanup (less ?: operators...) */
+		fstr->bv_len = atmp.bv_len +
+			( f->f_mr_dnattrs ? STRLENOF( ":dn" ) : 0 ) +
+			( !BER_BVISEMPTY( &f->f_mr_rule_text ) ? f->f_mr_rule_text.bv_len + 1 : 0 ) +
+			ntmp.bv_len + ( STRLENOF( "(:=)" ) );
+		fstr->bv_val = dc->op->o_tmpalloc( fstr->bv_len + 1, memctx );
+
+		snprintf( fstr->bv_val, fstr->bv_len + 1, "(%s%s%s%s:=%s)",
+			atmp.bv_val,
+			f->f_mr_dnattrs ? ":dn" : "",
+			!BER_BVISEMPTY( &f->f_mr_rule_text ) ? ":" : "",
+			!BER_BVISEMPTY( &f->f_mr_rule_text ) ? f->f_mr_rule_text.bv_val : "",
+			ntmp.bv_len ? ntmp.bv_val : "" );
+		ber_memfree_x( ntmp.bv_val, memctx );
+		break;
+
+	case SLAPD_FILTER_COMPUTED:
+		switch ( f->f_result ) {
+		/* FIXME: treat UNDEFINED as FALSE */
+		case SLAPD_COMPARE_UNDEFINED:
+			if ( META_BACK_TGT_NOUNDEFFILTER( dc->target ) ) {
+				return LDAP_COMPARE_FALSE;
+			}
+			/* fallthru */
+
+		case LDAP_COMPARE_FALSE:
+			if ( META_BACK_TGT_T_F( dc->target ) ) {
+				tmp = &ber_bvtf_false;
+				break;
+			}
+			tmp = &ber_bvfalse;
+			break;
+
+		case LDAP_COMPARE_TRUE:
+			if ( META_BACK_TGT_T_F( dc->target ) ) {
+				tmp = &ber_bvtf_true;
+				break;
+			}
+
+			tmp = &ber_bvtrue;
+			break;
+
+		default:
+			tmp = &ber_bverror;
+			break;
+		}
+
+		ber_dupbv_x( fstr, tmp, memctx );
+		break;
+
+	default:
+		ber_dupbv_x( fstr, &ber_bvunknown, memctx );
+		break;
+	}
+
+	return 0;
+}
+meta_search_candidate_t
+asyncmeta_back_search_start(
+				Operation *op,
+				SlapReply *rs,
+				a_metaconn_t *mc,
+				bm_context_t *bc,
+				int candidate,
+				struct berval		*prcookie,
+				ber_int_t		prsize,
+				int do_lock)
+{
+	SlapReply		*candidates = bc->candidates;
+	a_metainfo_t		*mi = ( a_metainfo_t * )mc->mc_info;
+	a_metatarget_t		*mt = mi->mi_targets[ candidate ];
+	a_metasingleconn_t	*msc = &mc->mc_conns[ candidate ];
+	a_dncookie		dc;
+	struct berval		realbase = op->o_req_dn;
+	char		**attrs;
+	int			realscope = op->ors_scope;
+	struct berval		mbase = BER_BVNULL;
+	int			rc;
+	struct berval	filterbv = BER_BVNULL;
+	meta_search_candidate_t	retcode;
+	int timelimit;
+	LDAPControl		**ctrls = NULL;
+	BerElement *ber = NULL;
+	ber_int_t	msgid;
+	ber_socket_t s = -1;
+#ifdef SLAPD_META_CLIENT_PR
+	LDAPControl		**save_ctrls = NULL;
+#endif /* SLAPD_META_CLIENT_PR */
+
+	/* this should not happen; just in case... */
+	if ( msc->msc_ld == NULL ) {
+		Debug( LDAP_DEBUG_ANY,
+			"%s: asyncmeta_back_search_start candidate=%d ld=NULL%s.\n",
+			op->o_log_prefix, candidate,
+			META_BACK_ONERR_STOP( mi ) ? "" : " (ignored)" );
+		candidates[ candidate ].sr_err = LDAP_OTHER;
+		if ( META_BACK_ONERR_STOP( mi ) ) {
+			return META_SEARCH_ERR;
+		}
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		return META_SEARCH_NOT_CANDIDATE;
+	}
+
+	Debug( LDAP_DEBUG_TRACE, "%s >>> asyncmeta_back_search_start: dn=%s filter=%s\n",
+	       op->o_log_prefix, op->o_req_dn.bv_val, op->ors_filterstr.bv_val );
+	/*
+	 * modifies the base according to the scope, if required
+	 */
+	if ( mt->mt_nsuffix.bv_len > op->o_req_ndn.bv_len ) {
+		switch ( op->ors_scope ) {
+		case LDAP_SCOPE_SUBTREE:
+			/*
+			 * make the target suffix the new base
+			 * FIXME: this is very forgiving, because
+			 * "illegal" searchBases may be turned
+			 * into the suffix of the target; however,
+			 * the requested searchBase already passed
+			 * thru the candidate analyzer...
+			 */
+			if ( dnIsSuffix( &mt->mt_nsuffix, &op->o_req_ndn ) ) {
+				realbase = mt->mt_nsuffix;
+				if ( mt->mt_scope == LDAP_SCOPE_SUBORDINATE ) {
+					realscope = LDAP_SCOPE_SUBORDINATE;
+				}
+
+			} else {
+				/*
+				 * this target is no longer candidate
+				 */
+				retcode = META_SEARCH_NOT_CANDIDATE;
+				goto doreturn;
+			}
+			break;
+
+		case LDAP_SCOPE_SUBORDINATE:
+		case LDAP_SCOPE_ONELEVEL:
+		{
+			struct berval	rdn = mt->mt_nsuffix;
+			rdn.bv_len -= op->o_req_ndn.bv_len + STRLENOF( "," );
+			if ( dnIsOneLevelRDN( &rdn )
+					&& dnIsSuffix( &mt->mt_nsuffix, &op->o_req_ndn ) )
+			{
+				/*
+				 * if there is exactly one level,
+				 * make the target suffix the new
+				 * base, and make scope "base"
+				 */
+				realbase = mt->mt_nsuffix;
+				if ( op->ors_scope == LDAP_SCOPE_SUBORDINATE ) {
+					if ( mt->mt_scope == LDAP_SCOPE_SUBORDINATE ) {
+						realscope = LDAP_SCOPE_SUBORDINATE;
+					} else {
+						realscope = LDAP_SCOPE_SUBTREE;
+					}
+				} else {
+					realscope = LDAP_SCOPE_BASE;
+				}
+				break;
+			} /* else continue with the next case */
+		}
+
+		case LDAP_SCOPE_BASE:
+			/*
+			 * this target is no longer candidate
+			 */
+			retcode = META_SEARCH_NOT_CANDIDATE;
+			goto doreturn;
+		}
+	}
+
+	/* check filter expression */
+	if ( mt->mt_filter ) {
+		metafilter_t *mf;
+		for ( mf = mt->mt_filter; mf; mf = mf->mf_next ) {
+			if ( regexec( &mf->mf_regex, op->ors_filterstr.bv_val, 0, NULL, 0 ) == 0 )
+				break;
+		}
+		/* nothing matched, this target is no longer a candidate */
+		if ( !mf ) {
+			retcode = META_SEARCH_NOT_CANDIDATE;
+			goto doreturn;
+		}
+	}
+
+	/*
+	 * Rewrite the search base, if required
+	 */
+	dc.op = op;
+	dc.target = mt;
+	dc.memctx = op->o_tmpmemctx;
+	dc.to_from = MASSAGE_REQ;
+	asyncmeta_dn_massage( &dc, &realbase, &mbase );
+
+	attrs = anlist2charray_x( op->ors_attrs, 0, op->o_tmpmemctx );
+
+	if ( op->ors_tlimit != SLAP_NO_LIMIT ) {
+		timelimit = op->ors_tlimit > 0 ? op->ors_tlimit : 1;
+	} else {
+		timelimit = -1;	/* no limit */
+	}
+
+#ifdef SLAPD_META_CLIENT_PR
+	save_ctrls = op->o_ctrls;
+	{
+		LDAPControl *pr_c = NULL;
+		int i = 0, nc = 0;
+
+		if ( save_ctrls ) {
+			for ( ; save_ctrls[i] != NULL; i++ );
+			nc = i;
+			pr_c = ldap_control_find( LDAP_CONTROL_PAGEDRESULTS, save_ctrls, NULL );
+		}
+
+		if ( pr_c != NULL ) nc--;
+		if ( mt->mt_ps > 0 || prcookie != NULL ) nc++;
+
+		if ( mt->mt_ps > 0 || prcookie != NULL || pr_c != NULL ) {
+			int src = 0, dst = 0;
+			BerElementBuffer berbuf;
+			BerElement *ber = (BerElement *)&berbuf;
+			struct berval val = BER_BVNULL;
+			ber_len_t len;
+
+			len = sizeof( LDAPControl * )*( nc + 1 ) + sizeof( LDAPControl );
+
+			if ( mt->mt_ps > 0 || prcookie != NULL ) {
+				struct berval nullcookie = BER_BVNULL;
+				ber_tag_t tag;
+
+				if ( prsize == 0 && mt->mt_ps > 0 ) prsize = mt->mt_ps;
+				if ( prcookie == NULL ) prcookie = &nullcookie;
+
+				ber_init2( ber, NULL, LBER_USE_DER );
+				tag = ber_printf( ber, "{iO}", prsize, prcookie );
+				if ( tag == LBER_ERROR ) {
+					/* error */
+					(void) ber_free_buf( ber );
+					goto done_pr;
+				}
+
+				tag = ber_flatten2( ber, &val, 0 );
+				if ( tag == LBER_ERROR ) {
+					/* error */
+					(void) ber_free_buf( ber );
+					goto done_pr;
+				}
+
+				len += val.bv_len + 1;
+			}
+
+			op->o_ctrls = op->o_tmpalloc( len, op->o_tmpmemctx );
+			if ( save_ctrls ) {
+				for ( ; save_ctrls[ src ] != NULL; src++ ) {
+					if ( save_ctrls[ src ] != pr_c ) {
+						op->o_ctrls[ dst ] = save_ctrls[ src ];
+						dst++;
+					}
+				}
+			}
+
+			if ( mt->mt_ps > 0 || prcookie != NULL ) {
+				op->o_ctrls[ dst ] = (LDAPControl *)&op->o_ctrls[ nc + 1 ];
+
+				op->o_ctrls[ dst ]->ldctl_oid = LDAP_CONTROL_PAGEDRESULTS;
+				op->o_ctrls[ dst ]->ldctl_iscritical = 1;
+
+				op->o_ctrls[ dst ]->ldctl_value.bv_val = (char *)&op->o_ctrls[ dst ][ 1 ];
+				AC_MEMCPY( op->o_ctrls[ dst ]->ldctl_value.bv_val, val.bv_val, val.bv_len + 1 );
+				op->o_ctrls[ dst ]->ldctl_value.bv_len = val.bv_len;
+				dst++;
+
+				(void)ber_free_buf( ber );
+			}
+
+			op->o_ctrls[ dst ] = NULL;
+		}
+done_pr:;
+	}
+#endif /* SLAPD_META_CLIENT_PR */
+
+	asyncmeta_set_msc_time(msc);
+	ctrls = op->o_ctrls;
+
+	if ( asyncmeta_controls_add( op, rs, mc, candidate, bc->is_root, &ctrls )
+		!= LDAP_SUCCESS )
+	{
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		retcode = META_SEARCH_NOT_CANDIDATE;
+		goto done;
+	}
+
+	/*
+	 * Starts the search
+	 */
+		/* someone reset the connection */
+	if (!( LDAP_BACK_CONN_ISBOUND( msc )
+	       || LDAP_BACK_CONN_ISANON( msc )) || msc->msc_ld == NULL ) {
+		Debug( asyncmeta_debug, "msc %p not initialized at %s:%d\n", msc, __FILE__, __LINE__ );
+		goto error_unavailable;
+	}
+	rc = asyncmeta_int_filter2bv( &dc, op->ors_filter, &filterbv );
+	if ( rc ) {
+		retcode = META_SEARCH_ERR;
+		goto done;
+	}
+
+	ber = ldap_build_search_req( msc->msc_ld,
+			mbase.bv_val, realscope, filterbv.bv_val,
+			attrs, op->ors_attrsonly,
+			ctrls, NULL, timelimit, op->ors_slimit, op->ors_deref,
+			&msgid );
+	if (!ber) {
+		Debug( asyncmeta_debug, "%s asyncmeta_back_search_start: Operation encoding failed with errno %d\n",
+		       op->o_log_prefix, msc->msc_ld->ld_errno );
+		rs->sr_err = LDAP_OPERATIONS_ERROR;
+		rs->sr_text = "Failed to encode proxied request";
+		retcode = META_SEARCH_ERR;
+		goto done;
+	}
+
+	if (ber) {
+		struct timeval tv = {0, mt->mt_network_timeout*1000};
+
+		if (!( LDAP_BACK_CONN_ISBOUND( msc )
+		       || LDAP_BACK_CONN_ISANON( msc )) || msc->msc_ld == NULL ) {
+			Debug( asyncmeta_debug, "msc %p not initialized at %s:%d\n", msc, __FILE__, __LINE__ );
+			goto error_unavailable;
+		}
+
+		ldap_get_option( msc->msc_ld, LDAP_OPT_DESC, &s );
+		if (s < 0) {
+			Debug( asyncmeta_debug, "msc %p not initialized at %s:%d\n", msc, __FILE__, __LINE__ );
+			goto error_unavailable;
+		}
+
+		rc = ldap_int_poll( msc->msc_ld, s, &tv, 1);
+		if (rc < 0) {
+			Debug( asyncmeta_debug, "msc %p not writable within network timeout %s:%d\n", msc, __FILE__, __LINE__ );
+			if ((msc->msc_result_time + META_BACK_RESULT_INTERVAL) < slap_get_time()) {
+				rc = LDAP_SERVER_DOWN;
+			} else {
+				goto error_unavailable;
+			}
+		} else {
+			candidates[ candidate ].sr_msgid = msgid;
+			rc = ldap_send_initial_request( msc->msc_ld, LDAP_REQ_SEARCH,
+							mbase.bv_val, ber, msgid );
+			if (rc == msgid)
+				rc = LDAP_SUCCESS;
+			else
+				rc = LDAP_SERVER_DOWN;
+			ber = NULL;
+		}
+
+		switch ( rc ) {
+		case LDAP_SUCCESS:
+			retcode = META_SEARCH_CANDIDATE;
+			asyncmeta_set_msc_time(msc);
+			goto done;
+
+		case LDAP_SERVER_DOWN:
+			/* do not lock if called from asyncmeta_handle_bind_result. Also do not reset the connection */
+			if (do_lock > 0) {
+				ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+				asyncmeta_reset_msc(NULL, mc, candidate, 0, __FUNCTION__);
+				ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			}
+			Debug( asyncmeta_debug, "msc %p ldap_send_initial_request failed. %s:%d\n", msc, __FILE__, __LINE__ );
+			goto error_unavailable;
+
+		default:
+			candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+			retcode = META_SEARCH_NOT_CANDIDATE;
+			goto done;
+		}
+	}
+
+error_unavailable:
+	if (ber)
+		ber_free(ber, 1);
+	switch (bc->nretries[candidate]) {
+	case -1: /* nretries = forever */
+		retcode = META_SEARCH_NEED_BIND;
+		ldap_pvt_thread_yield();
+		break;
+	case 0: /* no retries left */
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		rs->sr_err = LDAP_UNAVAILABLE;
+		rs->sr_text = "Unable to send search request to target";
+		retcode = META_SEARCH_ERR;
+		break;
+	default: /* more retries left - try to rebind and go again */
+		retcode = META_SEARCH_NEED_BIND;
+		bc->nretries[candidate]--;
+		ldap_pvt_thread_yield();
+		break;
+	}
+done:;
+#if 0
+	(void)mi->mi_ldap_extra->controls_free( op, rs, &ctrls );
+#endif
+#ifdef SLAPD_META_CLIENT_PR
+	if ( save_ctrls != op->o_ctrls ) {
+		op->o_tmpfree( op->o_ctrls, op->o_tmpmemctx );
+		op->o_ctrls = save_ctrls;
+	}
+#endif /* SLAPD_META_CLIENT_PR */
+
+	if ( mbase.bv_val != realbase.bv_val ) {
+		op->o_tmpfree( mbase.bv_val, op->o_tmpmemctx );
+	}
+
+doreturn:;
+	Debug( LDAP_DEBUG_TRACE, "%s <<< asyncmeta_back_search_start[%p] (fd %d)=%d\n", op->o_log_prefix, msc, s, candidates[candidate].sr_msgid );
+	return retcode;
+}
+
+int
+asyncmeta_back_search( Operation *op, SlapReply *rs )
+{
+	a_metainfo_t	*mi = ( a_metainfo_t * )op->o_bd->be_private;
+	time_t          timeout = 0;
+	int		rc = 0;
+	int		ncandidates = 0, initial_candidates = 0;
+	long		i;
+	SlapReply	*candidates = NULL;
+	void *thrctx = op->o_threadctx;
+	bm_context_t *bc;
+	a_metaconn_t *mc;
+	int msc_decr = 0;
+	int max_pending_ops = (mi->mi_max_pending_ops == 0) ? META_BACK_CFG_MAX_PENDING_OPS : mi->mi_max_pending_ops;
+	int check_bind = 0;
+
+	rs_assert_ready( rs );
+	rs->sr_flags &= ~REP_ENTRY_MASK; /* paranoia, we can set rs = non-entry */
+
+	/*
+	 * controls are set in ldap_back_dobind()
+	 *
+	 * FIXME: in case of values return filter, we might want
+	 * to map attrs and maybe rewrite value
+	 */
+
+	asyncmeta_new_bm_context(op, rs, &bc, mi->mi_ntargets, mi );
+	if (bc == NULL) {
+		rs->sr_err = LDAP_OTHER;
+		send_ldap_result(op, rs);
+		return rs->sr_err;
+	}
+
+	candidates = bc->candidates;
+	mc = asyncmeta_getconn( op, rs, candidates, NULL, LDAP_BACK_DONTSEND, 0);
+	if ( !mc || rs->sr_err != LDAP_SUCCESS) {
+		send_ldap_result(op, rs);
+		return rs->sr_err;
+	}
+
+	/*
+	 * Inits searches
+	 */
+
+	for ( i = 0; i < mi->mi_ntargets; i++ ) {
+		/* reset sr_msgid; it is used in most loops
+		 * to check if that target is still to be considered */
+		candidates[i].sr_msgid = META_MSGID_UNDEFINED;
+		/* a target is marked as candidate by asyncmeta_getconn();
+		 * if for any reason (an error, it's over or so) it is
+		 * no longer active, sr_msgid is set to META_MSGID_IGNORE
+		 * but it remains candidate, which means it has been active
+		 * at some point during the operation.  This allows to
+		 * use its response code and more to compute the final
+		 * response */
+		if ( !META_IS_CANDIDATE( &candidates[ i ] ) ) {
+			continue;
+		}
+
+		candidates[ i ].sr_matched = NULL;
+		candidates[ i ].sr_text = NULL;
+		candidates[ i ].sr_ref = NULL;
+		candidates[ i ].sr_ctrls = NULL;
+		candidates[ i ].sr_nentries = 0;
+		candidates[ i ].sr_type = -1;
+
+		/* get largest timeout among candidates */
+		if ( mi->mi_targets[ i ]->mt_timeout[ SLAP_OP_SEARCH ]
+			&& mi->mi_targets[ i ]->mt_timeout[ SLAP_OP_SEARCH ] > timeout )
+		{
+			timeout = mi->mi_targets[ i ]->mt_timeout[ SLAP_OP_SEARCH ];
+		}
+	}
+
+	if ( op->ors_tlimit != SLAP_NO_LIMIT && (timeout == 0 || op->ors_tlimit < timeout)) {
+		bc->searchtime = 1;
+		bc->timeout = op->ors_tlimit;
+	} else {
+		bc->timeout = timeout;
+	}
+
+	bc->stoptime = op->o_time + bc->timeout;
+	bc->bc_active = 1;
+
+	if (mc->pending_ops >= max_pending_ops) {
+		rs->sr_err = LDAP_BUSY;
+		rs->sr_text = "Maximum pending ops limit exceeded";
+		send_ldap_result(op, rs);
+		return rs->sr_err;
+	}
+
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	rc = asyncmeta_add_message_queue(mc, bc);
+	for ( i = 0; i < mi->mi_ntargets; i++ ) {
+		mc->mc_conns[i].msc_active++;
+	}
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+
+	if (rc != LDAP_SUCCESS) {
+		rs->sr_err = LDAP_BUSY;
+		rs->sr_text = "Maximum pending ops limit exceeded";
+		send_ldap_result(op, rs);
+		goto finish;
+	}
+
+	for ( i = 0; i < mi->mi_ntargets; i++ ) {
+		if ( !META_IS_CANDIDATE( &candidates[ i ] )
+			|| candidates[ i ].sr_err != LDAP_SUCCESS )
+		{
+			continue;
+		}
+retry:
+		if (bc->timeout && bc->stoptime < slap_get_time() && META_BACK_ONERR_STOP( mi )) {
+			int		timeout_err;
+			const char *timeout_text;
+			if (bc->searchtime) {
+				timeout_err = LDAP_TIMELIMIT_EXCEEDED;
+				timeout_text = NULL;
+			} else {
+				timeout_err = op->o_protocol >= LDAP_VERSION3 ?
+					LDAP_ADMINLIMIT_EXCEEDED : LDAP_OTHER;
+				timeout_text = "Operation timed out before it was sent to target";
+			}
+			rs->sr_err = timeout_err;
+			rs->sr_text = timeout_text;
+			asyncmeta_handle_onerr_stop(op,rs,mc,bc,i);
+			goto finish;
+
+		}
+
+		if (op->o_abandon) {
+			rs->sr_err = SLAPD_ABANDON;
+			asyncmeta_handle_onerr_stop(op,rs,mc,bc,i);
+			goto finish;
+		}
+
+		rc = asyncmeta_dobind_init_with_retry(op, rs, bc, mc, i);
+		switch (rc)
+		{
+		case META_SEARCH_CANDIDATE:
+			/* target is already bound, just send the search request */
+			ncandidates++;
+			Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_search: IS_CANDIDATE "
+			       "cnd=\"%ld\"\n", op->o_log_prefix, i );
+
+			rc = asyncmeta_back_search_start( op, rs, mc, bc, i,  NULL, 0 , 1);
+			if (rc == META_SEARCH_ERR) {
+				META_CANDIDATE_CLEAR(&candidates[i]);
+				candidates[ i ].sr_msgid = META_MSGID_IGNORE;
+				if ( META_BACK_ONERR_STOP( mi ) ) {
+					asyncmeta_handle_onerr_stop(op,rs,mc,bc,i);
+					goto finish;
+				}
+				else {
+					continue;
+				}
+			} else if (rc == META_SEARCH_NEED_BIND) {
+				goto retry;
+			}
+			break;
+		case META_SEARCH_NOT_CANDIDATE:
+			Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_search: NOT_CANDIDATE "
+			       "cnd=\"%ld\"\n", op->o_log_prefix, i );
+			candidates[ i ].sr_msgid = META_MSGID_IGNORE;
+			break;
+
+		case META_SEARCH_NEED_BIND:
+		case META_SEARCH_BINDING:
+			Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_search: BINDING "
+			       "cnd=\"%ld\" mc %p msc %p\n", op->o_log_prefix, i , mc, &mc->mc_conns[i]);
+			check_bind++;
+			ncandidates++;
+			/* Todo add the context to the message queue but do not send the request
+			 the receiver must send this when we are done binding */
+			/* question - how would do receiver know to which targets??? */
+			break;
+
+		case META_SEARCH_ERR:
+			Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_search: SEARCH_ERR "
+			       "cnd=\"%ldd\"\n", op->o_log_prefix, i );
+			candidates[ i ].sr_msgid = META_MSGID_IGNORE;
+			candidates[ i ].sr_type = REP_RESULT;
+
+			if ( META_BACK_ONERR_STOP( mi ) ) {
+				asyncmeta_handle_onerr_stop(op,rs,mc,bc,i);
+				goto finish;
+			}
+			else {
+				continue;
+			}
+			break;
+
+		default:
+			assert( 0 );
+			break;
+		}
+	}
+
+	initial_candidates = ncandidates;
+
+	if ( LogTest( LDAP_DEBUG_TRACE ) ) {
+		char	cnd[ SLAP_TEXT_BUFLEN ];
+		int	c;
+
+		for ( c = 0; c < mi->mi_ntargets; c++ ) {
+			if ( META_IS_CANDIDATE( &candidates[ c ] ) ) {
+				cnd[ c ] = '*';
+			} else {
+				cnd[ c ] = ' ';
+			}
+		}
+		cnd[ c ] = '\0';
+
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_search: ncandidates=%d "
+			"cnd=\"%s\"\n", op->o_log_prefix, ncandidates, cnd );
+	}
+
+	if ( initial_candidates == 0 ) {
+		/* NOTE: here we are not sending any matchedDN;
+		 * this is intended, because if the back-meta
+		 * is serving this search request, but no valid
+		 * candidate could be looked up, it means that
+		 * there is a hole in the mapping of the targets
+		 * and thus no knowledge of any remote superior
+		 * is available */
+		Debug( LDAP_DEBUG_ANY, "%s asyncmeta_back_search: "
+			"base=\"%s\" scope=%d: "
+			"no candidate could be selected\n",
+			op->o_log_prefix, op->o_req_dn.bv_val,
+			op->ors_scope );
+
+		/* FIXME: we're sending the first error we encounter;
+		 * maybe we should pick the worst... */
+		rc = LDAP_NO_SUCH_OBJECT;
+		for ( i = 0; i < mi->mi_ntargets; i++ ) {
+			if ( META_IS_CANDIDATE( &candidates[ i ] )
+				&& candidates[ i ].sr_err != LDAP_SUCCESS )
+			{
+				rc = candidates[ i ].sr_err;
+				break;
+			}
+		}
+		rs->sr_err = rc;
+		ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+		asyncmeta_drop_bc(mc, bc);
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+		send_ldap_result(op, rs);
+		goto finish;
+	}
+
+	/* If we were processing many targets the result from a pending Bind
+	 * on an earlier target may have arrived while we were sending to a
+	 * later target. See if we can now send our pending request.
+	 */
+	if ( check_bind ) {
+		for ( i = 0; i < mi->mi_ntargets; i++ ) {
+			if ( candidates[ i ].sr_msgid == META_MSGID_GOT_BIND ) {
+				rc = asyncmeta_back_search_start( op, rs, mc, bc, i, NULL, 0, 1 );
+				if ( rc == META_SEARCH_ERR ) {
+					META_CANDIDATE_CLEAR( &candidates[i] );
+					candidates[ i ].sr_msgid = META_MSGID_IGNORE;
+					if ( META_BACK_ONERR_STOP( mi ) ) {
+						asyncmeta_handle_onerr_stop(op,rs,mc,bc,i);
+						goto finish;
+					}
+				}
+			}
+		}
+	}
+
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	for ( i = 0; i < mi->mi_ntargets; i++ ) {
+		mc->mc_conns[i].msc_active--;
+	}
+	msc_decr = 1;
+
+	asyncmeta_start_listeners(mc, candidates, bc);
+	bc->bc_active--;
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+	rs->sr_err = SLAPD_ASYNCOP;
+
+finish:
+	/* we ended up straight here due to error and need to reset the msc_active*/
+	if (msc_decr == 0) {
+		ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+		for ( i = 0; i < mi->mi_ntargets; i++ ) {
+			mc->mc_conns[i].msc_active--;
+		}
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+	}
+	return rs->sr_err;
+}