ITS#8303 Asynchronous meta back-end for OpenLDAP

configure.in

@@ -316,6 +316,8 @@ OL_ARG_ENABLE(mdb,[    --enable-mdb	  enable mdb database backend],
 	yes, [no yes mod], ol_enable_backends)dnl
 OL_ARG_ENABLE(meta,[    --enable-meta	  enable metadirectory backend],
 	no, [no yes mod], ol_enable_backends)dnl
+OL_ARG_ENABLE(asyncmeta,[    --enable-asyncmeta	  enable asynchronous metadirectory backend],
+	no, [no yes mod], ol_enable_backends)dnl
 OL_ARG_ENABLE(monitor,[    --enable-monitor	  enable monitor backend],
 	yes, [no yes mod], ol_enable_backends)dnl
 OL_ARG_ENABLE(ndb,[    --enable-ndb	  enable MySQL NDB Cluster backend],
@@ -504,6 +506,10 @@ if test $ol_enable_meta/$ol_enable_ldap = yes/no ; then
 	AC_MSG_ERROR([--enable-meta requires --enable-ldap])
 fi
 
+if test $ol_enable_meta_async/$ol_enable_ldap = yes/no ; then
+	AC_MSG_ERROR([--enable-asyncmeta requires --enable-ldap])
+fi
+
 if test $ol_enable_lmpasswd = yes ; then
 	if test $ol_with_tls = no ; then
 		AC_MSG_ERROR([LAN Manager passwords require OpenSSL])
@@ -543,6 +549,7 @@ BUILD_HDB=no
 BUILD_LDAP=no
 BUILD_MDB=no
 BUILD_META=no
+BUILD_ASYNCMETA=no
 BUILD_MONITOR=no
 BUILD_NDB=no
 BUILD_NULL=no
@@ -2736,6 +2743,20 @@ if test "$ol_enable_meta" != no ; then
 	AC_DEFINE_UNQUOTED(SLAPD_META,$MFLAG,[define to support LDAP Metadirectory backend])
 fi
 
+if test "$ol_enable_meta_async" != no ; then
+	BUILD_SLAPD=yes
+	BUILD_ASYNCMETA=$ol_enable_meta_async
+	BUILD_REWRITE=yes
+	if test "$ol_enable_meta_async" = mod ; then
+		SLAPD_DYNAMIC_BACKENDS="$SLAPD_DYNAMIC_BACKENDS back-asyncmeta"
+		MFLAG=SLAPD_MOD_DYNAMIC
+	else
+		SLAPD_STATIC_BACKENDS="$SLAPD_STATIC_BACKENDS back-asyncmeta"
+		MFLAG=SLAPD_MOD_STATIC
+	fi
+	AC_DEFINE_UNQUOTED(SLAPD_ASYNCMETA,$MFLAG,[define to support LDAP Async Metadirectory backend])
+fi
+
 if test "$ol_enable_ndb" != no ; then
 	BUILD_SLAPD=yes
 	BUILD_NDB=$ol_enable_ndb
@@ -3142,6 +3163,7 @@ dnl backends
   AC_SUBST(BUILD_LDAP)
   AC_SUBST(BUILD_MDB)
   AC_SUBST(BUILD_META)
+  AC_SUBST(BUILD_ASYNCMETA)
   AC_SUBST(BUILD_MONITOR)
   AC_SUBST(BUILD_NDB)
   AC_SUBST(BUILD_NULL)
@@ -3253,6 +3275,7 @@ AC_CONFIG_FILES([Makefile:build/top.mk:Makefile.in:build/dir.mk]
 [servers/slapd/back-ldif/Makefile:build/top.mk:servers/slapd/back-ldif/Makefile.in:build/mod.mk]
 [servers/slapd/back-mdb/Makefile:build/top.mk:servers/slapd/back-mdb/Makefile.in:build/mod.mk]
 [servers/slapd/back-meta/Makefile:build/top.mk:servers/slapd/back-meta/Makefile.in:build/mod.mk]
+[servers/slapd/back-asyncmeta/Makefile:build/top.mk:servers/slapd/back-asyncmeta/Makefile.in:build/mod.mk]
 [servers/slapd/back-monitor/Makefile:build/top.mk:servers/slapd/back-monitor/Makefile.in:build/mod.mk]
 [servers/slapd/back-ndb/Makefile:build/top.mk:servers/slapd/back-ndb/Makefile.in:build/mod.mk]
 [servers/slapd/back-null/Makefile:build/top.mk:servers/slapd/back-null/Makefile.in:build/mod.mk]

doc/man/man5/slapd-asyncmeta.5

@@ -0,0 +1,487 @@
+.TH SLAPD-ASYNCMETA 5 "RELEASEDATE" "OpenLDAP LDVERSION"
+.\" Copyright 2016 The OpenLDAP Foundation.
+.\" Portions Copyright 2016 Symas Corporation.
+.\" Copying restrictions apply.  See the COPYRIGHT file.
+.\" $OpenLDAP$
+.\"
+
+.SH NAME
+slapd\-asyncmeta \- asynchronous metadirectory backend to slapd
+.SH SYNOPSIS
+ETCDIR/slapd.conf
+.SH DESCRIPTION
+The
+.B asyncmeta
+backend to
+.BR slapd (8)
+performs basic LDAP proxying with respect to a set of remote LDAP
+servers, called "targets".
+The information contained in these servers can be presented as
+belonging to a single Directory Information Tree (DIT).
+
+.LP
+A good knowledge of the functionality of the
+.BR slapd\-meta(5)
+backend  is recommended.   This  backend has been designed as
+an asynchronous version of the
+.B meta
+backend. Unlike
+.B meta
+, the operation handling threads are no longer pending
+on the response from the remote server, thus decreasing the
+number of threads necessary to handle the same load. While
+.B asyncmeta
+maintains the functionality of
+.B meta
+and has a largely similar codebase,
+some changes in operation and some new configuration directives have been
+added. Some configuration options, such as
+.B conn-ttl,
+.B single-conn
+and
+.B use-temporary-conn
+have been removed, as they are no longer relevant.
+.LP
+.B New connection handling:
+.LP
+
+Unlike
+.B meta,
+which caches bound connections, the
+.B asyncmeta
+works with a configured maximum number of connections per target.
+For each request redirected to a target, a different connection is selected.
+Each connection has a queue, to which the request is added before it is sent to the
+remote server, and is removed after the last response for that request is received.
+ For each new request, the connection with the smallest number of pending requests
+is selected, or using round\-robin if the numbers are equal.
+.LP
+.B Overlays:
+.LP
+Due to implementation specifics, there is no guarantee that any of the existing OpenLDAP overlays will work with
+.B asyncmeta
+backend.
+
+.SH EXAMPLES
+Refer to
+.B slapd\-meta(5)
+for configuration examples.
+
+.SH CONFIGURATION
+These
+.B slapd.conf
+options apply to the ASYNCMETA backend database.
+That is, they must follow a "database asyncmeta" line and come before any
+subsequent "backend" or "database" lines.
+Other database options are described in the
+.BR slapd.conf (5)
+manual page.
+
+.SH SPECIAL CONFIGURATION DIRECTIVES
+Target configuration starts with the "uri" directive.
+All the configuration directives that are not specific to targets
+should be defined first for clarity, including those that are common
+to all backends.
+They are:
+
+.TP
+.B default\-target none
+This directive forces the backend to reject all those operations
+that must resolve to a single target in case none or multiple
+targets are selected.
+They include: add, delete, modify, modrdn; compare is not included, as
+well as bind since, as they don't alter entries, in case of multiple
+matches an attempt is made to perform the operation on any candidate
+target, with the constraint that at most one must succeed.
+This directive can also be used when processing targets to mark a
+specific target as default.
+
+.TP
+.B dncache\-ttl {DISABLED|forever|<ttl>}
+This directive sets the time-to-live of the DN cache.
+This caches the target that holds a given DN to speed up target
+selection in case multiple targets would result from an uncached
+search; forever means cache never expires; disabled means no DN
+caching; otherwise a valid ( > 0 ) ttl is required, in the format
+illustrated for the
+.B idle\-timeout
+directive.
+
+.TP
+.B onerr {CONTINUE|report|stop}
+This directive allows to select the behavior in case an error is returned
+by one target during a search.
+The default, \fBcontinue\fP, consists in continuing the operation,
+trying to return as much data as possible.
+If the value is set to \fBstop\fP, the search is terminated as soon
+as an error is returned by one target, and the error is immediately
+propagated to the client.
+If the value is set to \fBreport\fP, the search is continuated to the end
+but, in case at least one target returned an error code, the first
+non-success error code is returned.
+
+.TP
+.B max\-timeout\-ops <number>
+Specify the number of consecutive timed out requests,
+after which the connection will be considered faulty and dropped.
+
+.TP
+.B max-pending-ops <number>
+The maximum number of pending requests stored in a connection's queue.
+The default is 128. When this number is exceeded,
+.B LDAP_BUSY
+will be returned to the client.
+
+.TP
+.B max-target-conns <number>
+The maximum number of connections per target. Unlike
+.B slapd\-meta(5),
+no new connections will be created
+once this number is reached. The default value is 255.
+
+.TP
+.B norefs <NO|yes>
+If
+.BR yes ,
+do not return search reference responses.
+By default, they are returned unless request is LDAPv2.
+If set before any target specification, it affects all targets, unless
+overridden by any per-target directive.
+
+.TP
+.B noundeffilter <NO|yes>
+If
+.BR yes ,
+return success instead of searching if a filter is undefined or contains
+undefined portions.
+By default, the search is propagated after replacing undefined portions
+with
+.BR (!(objectClass=*)) ,
+which corresponds to the empty result set.
+If set before any target specification, it affects all targets, unless
+overridden by any per-target directive.
+
+.TP
+.B protocol\-version {0,2,3}
+This directive indicates what protocol version must be used to contact
+the remote server.
+If set to 0 (the default), the proxy uses the same protocol version
+used by the client, otherwise the requested protocol is used.
+The proxy returns \fIunwillingToPerform\fP if an operation that is
+incompatible with the requested protocol is attempted.
+If set before any target specification, it affects all targets, unless
+overridden by any per-target directive.
+
+.TP
+.B pseudoroot\-bind\-defer {YES|no}
+This directive, when set to
+.BR yes ,
+causes the authentication to the remote servers with the pseudo-root
+identity (the identity defined in each
+.B idassert-bind
+directive) to be deferred until actually needed by subsequent operations.
+Otherwise, all binds as the rootdn are propagated to the targets.
+
+.TP
+.B quarantine <interval>,<num>[;<interval>,<num>[...]]
+Turns on quarantine of URIs that returned
+.IR LDAP_UNAVAILABLE ,
+so that an attempt to reconnect only occurs at given intervals instead
+of any time a client requests an operation.
+The pattern is: retry only after at least
+.I interval
+seconds elapsed since last attempt, for exactly
+.I num
+times; then use the next pattern.
+If
+.I num
+for the last pattern is "\fB+\fP", it retries forever; otherwise,
+no more retries occur.
+This directive must appear before any target specification;
+it affects all targets with the same pattern.
+
+.TP
+.B rebind\-as\-user {NO|yes}
+If this option is given, the client's bind credentials are remembered
+for rebinds, when trying to re-establish a broken connection,
+or when chasing a referral, if
+.B chase\-referrals
+is set to
+.IR yes .
+
+.TP
+.B session\-tracking\-request {NO|yes}
+Adds session tracking control for all requests.
+The client's IP and hostname, and the identity associated to each request,
+if known, are sent to the remote server for informational purposes.
+This directive is incompatible with setting \fIprotocol\-version\fP to 2.
+If set before any target specification, it affects all targets, unless
+overridden by any per-target directive.
+
+.SH TARGET SPECIFICATION
+Target specification starts with a "uri" directive:
+
+.TP
+.B uri <protocol>://[<host>]/<naming context> [...]
+Identical to
+.B meta.
+See
+.B slapd\-meta(5)
+for details.
+
+.TP
+.B acl\-authcDN "<administrative DN for access control purposes>"
+DN which is used to query the target server for acl checking,
+as in the LDAP backend; it is supposed to have read access
+on the target server to attributes used on the proxy for acl checking.
+There is no risk of giving away such values; they are only used to
+check permissions.
+.B The acl\-authcDN identity is by no means implicitly used by the proxy
+.B when the client connects anonymously.
+
+.TP
+.B acl\-passwd <password>
+Password used with the
+.B
+acl\-authcDN
+above.
+
+.TP
+.B bind\-timeout <microseconds>
+This directive defines the timeout, in microseconds, used when polling
+for response after an asynchronous bind connection. See
+.B slapd\-meta(5)
+for details.
+
+.TP
+.B chase\-referrals {YES|no}
+enable/disable automatic referral chasing, which is delegated to the
+underlying libldap, with rebinding eventually performed if the
+\fBrebind\-as\-user\fP directive is used.  The default is to chase referrals.
+If set before any target specification, it affects all targets, unless
+overridden by any per-target directive.
+
+.TP
+.B client\-pr {accept-unsolicited|DISABLE|<size>}
+This feature allows to use RFC 2696 Paged Results control when performing
+search operations with a specific target,
+irrespective of the client's request. See
+.B slapd\-meta(5)
+for details.
+
+.TP
+.B default\-target [<target>]
+The "default\-target" directive can also be used during target specification.
+With no arguments it marks the current target as the default.
+The optional number marks target <target> as the default one, starting
+from 1.
+Target <target> must be defined.
+
+.TP
+.B filter <pattern>
+This directive allows specifying a
+.BR regex (5)
+pattern to indicate what search filter terms are actually served by a target.
+
+In a search request, if the search filter matches the \fIpattern\fP
+the target is considered while fulfilling the request; otherwise
+the target is ignored. There may be multiple occurrences of
+the
+.B filter
+directive for each target.
+
+.TP
+.B idassert\-authzFrom <authz-regexp>
+if defined, selects what
+.I local
+identities are authorized to exploit the identity assertion feature.
+The string
+.B <authz-regexp>
+follows the rules defined for the
+.I authzFrom
+attribute.
+See
+.BR slapd.conf (5),
+section related to
+.BR authz\-policy ,
+for details on the syntax of this field.
+
+.HP
+.hy 0
+.B idassert\-bind
+.B bindmethod=none|simple|sasl [binddn=<simple DN>] [credentials=<simple password>]
+.B [saslmech=<SASL mech>] [secprops=<properties>] [realm=<realm>]
+.B [authcId=<authentication ID>] [authzId=<authorization ID>]
+.B [authz={native|proxyauthz}] [mode=<mode>] [flags=<flags>]
+.B [starttls=no|yes|critical]
+.B [tls_cert=<file>]
+.B [tls_key=<file>]
+.B [tls_cacert=<file>]
+.B [tls_cacertdir=<path>]
+.B [tls_reqcert=never|allow|try|demand]
+.B [tls_ciphersuite=<ciphers>]
+.B [tls_protocol_min=<major>[.<minor>]]
+.B [tls_crlcheck=none|peer|all]
+Allows to define the parameters of the authentication method that is
+internally used by the proxy to authorize connections that are
+authenticated by other databases. See
+.B slapd\-meta(5)
+for details.
+
+.TP
+.B idle\-timeout <time>
+This directive causes a a persistent connection  to  be  dropped after
+it  has been idle for the specified time. The connection will be re-created
+the next time it is selected for use. A connection is considered idle if no
+attempts have been made by the backend to use it to send a request to
+the backend server. If there are still pending requests in
+its queue, the connection will be dropped after the last
+request one has either received a result or has timed out.
+
+[<d>d][<h>h][<m>m][<s>[s]]
+
+where <d>, <h>, <m> and <s> are respectively treated as days, hours,
+minutes and seconds.
+If set before any target specification, it affects all targets, unless
+overridden by any per-target directive.
+
+.TP
+.B keepalive  <idle>:<probes>:<interval>
+The
+.B keepalive
+parameter sets the values of \fIidle\fP, \fIprobes\fP, and \fIinterval\fP
+used to check whether a socket is alive;
+.I idle
+is the number of seconds a connection needs to remain idle before TCP
+starts sending keepalive probes;
+.I probes
+is the maximum number of keepalive probes TCP should send before dropping
+the connection;
+.I interval
+is interval in seconds between individual keepalive probes.
+Only some systems support the customization of these values;
+the
+.B keepalive
+parameter is ignored otherwise, and system-wide settings are used.
+
+.TP
+.B map "{attribute|objectclass} [<local name>|*] {<foreign name>|*}"
+This maps object classes and attributes as in the LDAP backend.
+See
+.BR slapd\-ldap (5).
+
+.TP
+.B network\-timeout <time>
+Sets the network timeout value after which
+.BR poll (2)/ select (2)
+following a
+.BR connect (2)
+returns in case of no activity.
+The value is in seconds, and it can be specified as for
+.BR idle\-timeout .
+If set before any target specification, it affects all targets, unless
+overridden by any per-target directive.
+
+.TP
+.B nretries {forever|never|<nretries>}
+This directive defines how many times a bind should be retried
+in case of temporary failure in contacting a target.  If defined
+before any target specification, it applies to all targets (by default,
+.BR 3
+times);
+the global value can be overridden by redefinitions inside each target
+specification.
+
+.TP
+.B rewrite* ...
+The rewrite options are identical to the
+.B meta
+backend. See the
+.B REWRITING
+section of
+.B slapd\-meta(5).
+
+.TP
+.B subtree\-{exclude|include} "<rule>"
+This directive allows to indicate what subtrees are actually served
+by a target. See
+.B slapd\-meta(5)
+for details.
+
+.TP
+.B suffixmassage "<virtual naming context>" "<real naming context>"
+All the directives starting with "rewrite" refer to the rewrite engine
+that has been added to slapd. See
+.B slapd\-meta(5)
+for details.
+
+.TP
+.B t\-f\-support {NO|yes|discover}
+enable if the remote server supports absolute filters
+(see \fIRFC 4526\fP for details).
+If set to
+.BR discover ,
+support is detected by reading the remote server's root DSE.
+If set before any target specification, it affects all targets, unless
+overridden by any per-target directive.
+
+.TP
+.B timeout [<op>=]<val> [...]
+This directive allows to set per-operation timeouts.
+Operations can be
+
+\fB<op> ::= bind, add, delete, modrdn, modify, compare, search\fP
+
+See
+.B slapd\-meta(5)
+for details.
+
+.TP
+.B tls {[try\-]start|[try\-]propagate}
+execute the StartTLS extended operation when the connection is initialized;
+only works if the URI directive protocol scheme is not \fBldaps://\fP.
+\fBpropagate\fP issues the StartTLS operation only if the original
+connection did.
+The \fBtry\-\fP prefix instructs the proxy to continue operations
+if the StartTLS operation failed; its use is highly deprecated.
+If set before any target specification, it affects all targets, unless
+overridden by any per-target directive.
+
+.SH SCENARIOS
+See
+.B slapd\-meta(5)
+for configuration scenarios.
+
+.SH ACLs
+ACL behavior is identical to meta. See
+.B slapd\-meta(5).
+
+.SH ACCESS CONTROL
+The
+.B asyncmeta
+backend does not honor all ACL semantics as described in
+.BR slapd.access (5).
+In general, access checking is delegated to the remote server(s).
+Only
+.B read (=r)
+access to the
+.B entry
+pseudo-attribute and to the other attribute values of the entries
+returned by the
+.B search
+operation is honored, which is performed by the frontend.
+
+.SH FILES
+.TP
+ETCDIR/slapd.conf
+default slapd configuration file
+.SH SEE ALSO
+.BR slapd.conf (5),
+.BR slapd\-meta (5),
+.BR slapd\-ldap (5),
+.BR slapo\-pcache (5),
+.BR slapd (8),
+.BR regex (7),
+.BR re_format (7).
+.SH AUTHOR
+Nadezhda Ivanova, based on back-meta by Pierangelo Masarati.

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 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 unbind.c add.c compare.c \
+		delete.c modify.c modrdn.c suffixmassage.c map.c \
+		conn.c candidates.c dncache.c meta_result.c abandon.c
+OBJS	= init.lo config.lo search.lo message_queue.lo bind.lo unbind.lo add.lo compare.lo \
+		delete.lo modify.lo modrdn.lo suffixmassage.lo map.lo \
+		conn.lo candidates.lo dncache.lo meta_result.lo abandon.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_R_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 $@

servers/slapd/back-asyncmeta/abandon.c

@@ -0,0 +1,52 @@
+/* abandon.c - abandon request handler for back-asyncmeta */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016 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"
+
+/* function is unused */
+int
+asyncmeta_back_abandon( Operation *op, SlapReply *rs )
+{
+	Operation *t_op;
+
+	/* Find the ops being abandoned */
+	ldap_pvt_thread_mutex_lock( &op->o_conn->c_mutex );
+
+	LDAP_STAILQ_FOREACH( t_op, &op->o_conn->c_ops, o_next ) {
+		if ( t_op->o_msgid == op->orn_msgid ) {
+			t_op->o_abandon = 1;
+		}
+	}
+	ldap_pvt_thread_mutex_unlock( &op->o_conn->c_mutex );
+
+	return LDAP_SUCCESS;
+}

servers/slapd/back-asyncmeta/add.c

@@ -0,0 +1,368 @@
+/* add.c - add request handler for back-asyncmeta */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016 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"
+#include "../../../libraries/libldap/ldap-int.h"
+
+void
+asyncmeta_sender_error(Operation *op,
+		       SlapReply *rs,
+		       slap_callback *cb)
+{
+	if (cb != NULL) {
+		op->o_callback = cb;
+	}
+	send_ldap_result(op, rs);
+}
+
+meta_search_candidate_t
+asyncmeta_back_add_start(Operation *op,
+			 SlapReply *rs,
+			 a_metaconn_t *mc,
+			 bm_context_t *bc,
+			 int candidate)
+{
+	int		isupdate;
+	Attribute	*a;
+	int i;
+	LDAPMod		**attrs;
+	struct berval	mapped;
+	a_dncookie	dc;
+	a_metainfo_t	*mi = mc->mc_info;
+	a_metatarget_t	*mt = mi->mi_targets[ candidate ];
+	struct berval   mdn;
+	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, nretries = 1;
+
+
+	dc.target = mt;
+	dc.conn = op->o_conn;
+	dc.rs = rs;
+	dc.ctx = "addDN";
+
+	mdn.bv_len = 0;
+
+	switch (asyncmeta_dn_massage( &dc, &bc->op->o_req_dn, &mdn ) )
+	{
+	case LDAP_SUCCESS:
+		break;
+	case LDAP_UNWILLING_TO_PERFORM:
+		rs->sr_err = LDAP_UNWILLING_TO_PERFORM;
+		rs->sr_text = "Operation not allowed";
+		retcode = META_SEARCH_ERR;
+		goto doreturn;
+	default:
+		rs->sr_err = LDAP_NO_SUCH_OBJECT;
+		retcode = META_SEARCH_NOT_CANDIDATE;
+		goto doreturn;
+	}
+
+	/* 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 = ch_malloc( sizeof( LDAPMod * )*i );
+
+	dc.ctx = "addAttrDN";
+	isupdate = be_shadow_update( op );
+	for ( i = 0, a = op->ora_e->e_attrs; a; a = a->a_next ) {
+		int j, is_oc = 0;
+
+		if ( !isupdate && !get_relax( op ) && a->a_desc->ad_type->sat_no_user_mod  )
+		{
+			continue;
+		}
+
+		if ( a->a_desc == slap_schema.si_ad_objectClass
+				|| a->a_desc == slap_schema.si_ad_structuralObjectClass )
+		{
+			is_oc = 1;
+			mapped = a->a_desc->ad_cname;
+
+		} else {
+			asyncmeta_map( &mt->mt_rwmap.rwm_at,
+					&a->a_desc->ad_cname, &mapped, BACKLDAP_MAP );
+			if ( BER_BVISNULL( &mapped ) || BER_BVISEMPTY( &mapped ) ) {
+				continue;
+			}
+		}
+
+		attrs[ i ] = ch_malloc( sizeof( LDAPMod ) );
+		if ( attrs[ i ] == NULL ) {
+			continue;
+		}
+		attrs[ i ]->mod_op = LDAP_MOD_BVALUES;
+		attrs[ i ]->mod_type = mapped.bv_val;
+
+		if ( is_oc ) {
+			for ( j = 0; !BER_BVISNULL( &a->a_vals[ j ] ); j++ );
+
+			attrs[ i ]->mod_bvalues =
+				(struct berval **)ch_malloc( ( j + 1 ) *
+				sizeof( struct berval * ) );
+			for ( j = 0; !BER_BVISNULL( &a->a_vals[ j ] ); ) {
+				struct ldapmapping	*mapping;
+
+				asyncmeta_mapping( &mt->mt_rwmap.rwm_oc,
+						&a->a_vals[ j ], &mapping, BACKLDAP_MAP );
+
+				if ( mapping == NULL ) {
+					if ( mt->mt_rwmap.rwm_oc.drop_missing ) {
+						continue;
+					}
+					attrs[ i ]->mod_bvalues[ j ] = &a->a_vals[ j ];
+
+				} else {
+					attrs[ i ]->mod_bvalues[ j ] = &mapping->dst;
+				}
+				j++;
+			}
+			attrs[ i ]->mod_bvalues[ j ] = NULL;
+
+		} else {
+			/*
+			 * FIXME: dn-valued attrs should be rewritten
+			 * to allow their use in ACLs at the back-ldap
+			 * level.
+			 */
+			if ( a->a_desc->ad_type->sat_syntax ==
+				slap_schema.si_syn_distinguishedName )
+			{
+				(void)asyncmeta_dnattr_rewrite( &dc, a->a_vals );
+				if ( a->a_vals == NULL ) {
+					continue;
+				}
+			}
+
+			for ( j = 0; !BER_BVISNULL( &a->a_vals[ j ] ); j++ )
+				;
+
+			attrs[ i ]->mod_bvalues = ch_malloc( ( j + 1 ) * sizeof( struct berval * ) );
+			for ( j = 0; !BER_BVISNULL( &a->a_vals[ j ] ); j++ ) {
+				attrs[ i ]->mod_bvalues[ j ] = &a->a_vals[ j ];
+			}
+			attrs[ i ]->mod_bvalues[ j ] = NULL;
+		}
+		i++;
+	}
+	attrs[ i ] = NULL;
+
+retry:;
+	ctrls = op->o_ctrls;
+	if ( asyncmeta_controls_add( op, rs, mc, candidate, &ctrls ) != LDAP_SUCCESS )
+	{
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		retcode = META_SEARCH_ERR;
+		goto done;
+	}
+
+	ber = ldap_build_add_req( msc->msc_ld, mdn.bv_val, attrs, ctrls, NULL, &msgid);
+	if (ber) {
+		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;
+
+		switch ( rc ) {
+		case LDAP_SUCCESS:
+			retcode = META_SEARCH_CANDIDATE;
+			asyncmeta_set_msc_time(msc);
+			break;
+
+		case LDAP_SERVER_DOWN:
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+			asyncmeta_clear_one_msc(NULL, mc, candidate);
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			if ( nretries && asyncmeta_retry( op, rs, &mc, candidate, LDAP_BACK_DONTSEND ) ) {
+				nretries = 0;
+				/* if the identity changed, there might be need to re-authz */
+				(void)mi->mi_ldap_extra->controls_free( op, rs, &ctrls );
+				goto retry;
+			}
+
+		default:
+			candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+			retcode = META_SEARCH_ERR;
+		}
+	}
+
+done:
+
+	(void)mi->mi_ldap_extra->controls_free( op, rs, &ctrls );
+
+	for ( --i; i >= 0; --i ) {
+		free( attrs[ i ]->mod_bvalues );
+		free( attrs[ i ] );
+	}
+	free( attrs );
+	if ( mdn.bv_val != op->ora_e->e_dn ) {
+		free( mdn.bv_val );
+		BER_BVZERO( &mdn );
+	}
+
+doreturn:;
+	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;
+	OperationBuffer opbuf;
+	bm_context_t *bc;
+	SlapReply *candidates;
+	slap_callback *cb = op->o_callback;
+
+	Debug(LDAP_DEBUG_ARGS, "==> asyncmeta_back_add: %s\n",
+	      op->o_req_dn.bv_val, 0, 0 );
+
+	asyncmeta_new_bm_context(op, rs, &bc, mi->mi_ntargets );
+	if (bc == NULL) {
+		rs->sr_err = LDAP_OTHER;
+		asyncmeta_sender_error(op, rs, cb);
+		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) {
+		asyncmeta_sender_error(op, rs, cb);
+		asyncmeta_clear_bm_context(bc);
+		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;
+
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	rc = asyncmeta_add_message_queue(mc, bc);
+	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";
+		asyncmeta_clear_bm_context(bc);
+		asyncmeta_sender_error(op, rs, cb);
+		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=\"%ld\"\n", op->o_log_prefix, candidate , 0);
+
+		rc = asyncmeta_back_add_start( op, rs, mc, bc, candidate);
+		if (rc == META_SEARCH_ERR) {
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+			asyncmeta_drop_bc(mc, bc);
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			asyncmeta_sender_error(op, rs, cb);
+			asyncmeta_clear_bm_context(bc);
+			goto finish;
+
+		}
+			break;
+	case META_SEARCH_NOT_CANDIDATE:
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_add: NOT_CANDIDATE "
+		       "cnd=\"%ld\"\n", op->o_log_prefix, candidate , 0);
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+		asyncmeta_drop_bc(mc, bc);
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+		asyncmeta_sender_error(op, rs, cb);
+		asyncmeta_clear_bm_context(bc);
+		goto finish;
+
+	case META_SEARCH_NEED_BIND:
+	case META_SEARCH_CONNECTING:
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_add: NEED_BIND "
+		       "cnd=\"%ld\" %p\n", op->o_log_prefix, candidate , &mc->mc_conns[candidate]);
+		rc = asyncmeta_dobind_init(op, rs, bc, mc, candidate);
+		if (rc == META_SEARCH_ERR) {
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+			asyncmeta_drop_bc(mc, bc);
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			asyncmeta_sender_error(op, rs, cb);
+			asyncmeta_clear_bm_context(bc);
+			goto finish;
+		}
+		break;
+	case META_SEARCH_BINDING:
+			Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_add: BINDING "
+			       "cnd=\"%ld\" %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_add: ERR "
+			       "cnd=\"%ldd\"\n", op->o_log_prefix, candidate , 0);
+			candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+			candidates[ candidate ].sr_type = REP_RESULT;
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+			asyncmeta_drop_bc(mc, bc);
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			asyncmeta_sender_error(op, rs, cb);
+			asyncmeta_clear_bm_context(bc);
+			goto finish;
+		default:
+			assert( 0 );
+			break;
+		}
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	asyncmeta_start_one_listener(mc, candidates, candidate);
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+finish:
+	return rs->sr_err;
+}

servers/slapd/back-asyncmeta/back-asyncmeta.h

@@ -0,0 +1,847 @@
+/* back-asyncmeta.h - main header file for back-asyncmeta module */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016 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
+
+#ifndef ENABLE_REWRITE
+#error "--enable-rewrite is required!"
+#endif
+
+#ifdef LDAP_DEVEL
+#define SLAPD_META_CLIENT_PR 1
+#endif /* LDAP_DEVEL */
+
+#include "proto-asyncmeta.h"
+
+/* String rewrite library */
+#include "rewrite.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 */
+
+/* from back-ldap.h before rwm removal */
+struct ldapmap {
+	int drop_missing;
+
+	Avlnode *map;
+	Avlnode *remap;
+};
+
+struct ldapmapping {
+	struct berval src;
+	struct berval dst;
+};
+
+struct ldaprwmap {
+	/*
+	 * DN rewriting
+	 */
+	struct rewrite_info *rwm_rw;
+	BerVarray rwm_bva_rewrite;
+
+	/*
+	 * Attribute/objectClass mapping
+	 */
+	struct ldapmap rwm_oc;
+	struct ldapmap rwm_at;
+	BerVarray rwm_bva_map;
+};
+
+/* Whatever context asyncmeta_dn_massage needs... */
+typedef struct a_dncookie {
+	struct a_metatarget_t	*target;
+
+	Connection		*conn;
+	char			*ctx;
+	SlapReply		*rs;
+} a_dncookie;
+
+int asyncmeta_dn_massage(a_dncookie *dc, struct berval *dn,
+	struct berval *res);
+
+extern int asyncmeta_conn_dup( void *c1, void *c2 );
+extern void asyncmeta_conn_free( void *c );
+
+/* attributeType/objectClass mapping */
+int asyncmeta_mapping_cmp (const void *, const void *);
+int asyncmeta_mapping_dup (void *, void *);
+
+void asyncmeta_map_init ( struct ldapmap *lm, struct ldapmapping ** );
+int asyncmeta_mapping ( struct ldapmap *map, struct berval *s,
+	struct ldapmapping **m, int remap );
+void asyncmeta_map ( struct ldapmap *map, struct berval *s, struct berval *m,
+	int remap );
+#define BACKLDAP_MAP	0
+#define BACKLDAP_REMAP	1
+char *
+asyncmeta_map_filter(
+	struct ldapmap *at_map,
+	struct ldapmap *oc_map,
+	struct berval *f,
+	int remap );
+
+int
+asyncmeta_map_attrs(
+	Operation *op,
+	struct ldapmap *at_map,
+	AttributeName *a,
+	int remap,
+	char ***mapped_attrs );
+
+extern int
+asyncmeta_filter_map_rewrite(
+	a_dncookie	*dc,
+	Filter		*f,
+	struct berval	*fstr,
+	int		remap,
+	void		*memctx );
+
+/* suffix massaging by means of librewrite */
+extern int
+asyncmeta_suffix_massage_config( struct rewrite_info *info,
+	struct berval *pvnc,
+	struct berval *nvnc,
+	struct berval *prnc,
+	struct berval *nrnc );
+
+extern int
+asyncmeta_back_referral_result_rewrite(
+	a_dncookie	*dc,
+	BerVarray	a_vals,
+	void		*memctx );
+extern int
+asyncmeta_dnattr_rewrite(
+	a_dncookie	*dc,
+	BerVarray	a_vals );
+extern int
+asyncmeta_dnattr_result_rewrite(
+	a_dncookie	*dc,
+	BerVarray	a_vals );
+
+
+/* (end of) from back-ldap.h before rwm removal */
+
+/*
+ * 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_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))
+
+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_SLIST_ENTRY(bm_context_t) bc_next;
+	time_t			timeout;
+	time_t          stoptime;
+	ldap_back_send_t	sendok;
+	ldap_back_send_t	retrying;
+	int candidate_match;
+	int sent;
+	int bc_active;
+	int searchtime;	/* stoptime is a search timelimit */
+	int is_ok;
+	SlapReply		rs;
+	Operation		*op;
+	LDAPControl	**ctrls;
+	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;
+	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
+
+	int msc_timeout_ops;
+		/* 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_SLIST_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	(10)
+
+	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_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
+
+	struct ldaprwmap	mt_rwmap;
+
+	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
+/* the interval of the timeout checking loop in microseconds
+ * possibly make this configurabe? */
+#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;
+
+} a_metainfo_t;
+
+typedef enum meta_op_type {
+	META_OP_ALLOW_MULTIPLE = 0,
+	META_OP_REQUIRE_SINGLE,
+	META_OP_REQUIRE_ALL
+} meta_op_type;
+
+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_retry(
+	Operation		*op,
+	SlapReply		*rs,
+	a_metaconn_t		**mcp,
+	int			candidate,
+	ldap_back_send_t	sendok );
+
+extern void
+asyncmeta_conn_free(
+	void			*v_mc );
+
+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_dobind(
+	Operation		*op,
+	SlapReply		*rs,
+	a_metaconn_t		*mc,
+	ldap_back_send_t	sendok,
+	SlapReply               *candidates);
+
+extern int
+asyncmeta_single_dobind(
+	Operation		*op,
+	SlapReply		*rs,
+	a_metaconn_t		**mcp,
+	int			candidate,
+	ldap_back_send_t	sendok,
+	int			retries,
+	int			dolock );
+
+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_cancel(
+	a_metaconn_t		*mc,
+	Operation		*op,
+	SlapReply		*rs,
+	ber_int_t		msgid,
+	int			candidate,
+	ldap_back_send_t	sendok );
+
+extern int
+asyncmeta_op_result(
+	a_metaconn_t		*mc,
+	Operation		*op,
+	SlapReply		*rs,
+	int			candidate,
+	ber_int_t		msgid,
+	time_t			timeout,
+	ldap_back_send_t	sendok );
+
+extern int
+asyncmeta_controls_add(
+	Operation	*op,
+	SlapReply	*rs,
+	a_metaconn_t	*mc,
+	int		candidate,
+	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 void
+asyncmeta_back_map_free( struct ldapmap *lm );
+
+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)
+
+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);
+
+bm_context_t *
+asyncmeta_find_message(ber_int_t msgid, a_metaconn_t *mc, int candidate);
+
+bm_context_t *
+asyncmeta_find_message_by_opmsguid(ber_int_t msgid, a_metaconn_t *mc, int remove);
+
+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 );
+
+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);
+void asyncmeta_clear_message_queue(a_metasingleconn_t *msc);
+
+int asyncmeta_back_cancel(
+	a_metaconn_t	*mc,
+	Operation		*op,
+	ber_int_t		msgid,
+	int				candidate );
+
+int
+asyncmeta_back_cancel_msc(
+	Operation		*op,
+	SlapReply		*rs,
+	ber_int_t		msgid,
+	a_metasingleconn_t	*msc,
+	int                     candidate,
+	ldap_back_send_t	sendok );
+
+int
+asyncmeta_back_abandon_candidate(
+	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);
+int asyncmeta_start_listeners(a_metaconn_t *mc, SlapReply *candidates);
+int asyncmeta_start_one_listener(a_metaconn_t *mc, SlapReply *candidates, 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 );
+
+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);
+meta_search_candidate_t
+asyncmeta_back_modify_start(Operation *op,
+			 SlapReply *rs,
+			 a_metaconn_t *mc,
+			 bm_context_t *bc,
+			 int candidate);
+
+meta_search_candidate_t
+asyncmeta_back_modrdn_start(Operation *op,
+			 SlapReply *rs,
+			 a_metaconn_t *mc,
+			 bm_context_t *bc,
+			 int candidate);
+meta_search_candidate_t
+asyncmeta_back_delete_start(Operation *op,
+			 SlapReply *rs,
+			 a_metaconn_t *mc,
+			 bm_context_t *bc,
+			 int candidate);
+
+meta_search_candidate_t
+asyncmeta_back_compare_start(Operation *op,
+			 SlapReply *rs,
+			 a_metaconn_t *mc,
+			 bm_context_t *bc,
+			 int candidate);
+
+
+void
+asyncmeta_sender_error(Operation *op,
+		       SlapReply *rs,
+		       slap_callback *cb);
+
+
+LDAP_END_DECL
+
+#endif /* SLAPD_ASYNCMETA_H */

servers/slapd/back-asyncmeta/candidates.c

@@ -0,0 +1,289 @@
+/* candidates.c - candidate targets selection and processing for
+ * back-asyncmeta */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016 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;
+
+			} else {
+				return META_TARGET_MULTIPLE;
+			}
+		}
+	}
+
+	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;
+}
+
+int
+asyncmeta_clear_one_msc(
+	Operation	*op,
+	a_metaconn_t	*mc,
+	int		candidate )
+{
+	a_metasingleconn_t *msc;
+	if (mc == NULL) {
+		return 0;
+	}
+	msc = &mc->mc_conns[candidate];
+	if (msc->conn) {
+		connection_client_stop( msc->conn );
+		msc->conn = NULL;
+	}
+	if ( msc->msc_ld != NULL ) {
+
+#ifdef DEBUG_205
+		char	buf[ BUFSIZ ];
+
+		snprintf( buf, sizeof( buf ), "asyncmeta_clear_one_msc ldap_unbind_ext[%d] ld=%p",
+			candidate, (void *)msc->msc_ld );
+		Debug( LDAP_DEBUG_ANY, "### %s %s\n",
+		       op ? op->o_log_prefix : "", buf, 0 );
+#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_mscflags = 0;
+	msc->msc_timeout_ops = 0;
+	return 0;
+}

servers/slapd/back-asyncmeta/compare.c

@@ -0,0 +1,293 @@
+/* compare.c - compare exop handler for back-asyncmeta */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016 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 "../../../libraries/liblber/lber-int.h"
+#include "../../../libraries/libldap/ldap-int.h"
+
+meta_search_candidate_t
+asyncmeta_back_compare_start(Operation *op,
+			    SlapReply *rs,
+			    a_metaconn_t *mc,
+			    bm_context_t *bc,
+			    int candidate)
+{
+	a_dncookie	dc;
+	a_metainfo_t	*mi = mc->mc_info;
+	a_metatarget_t	*mt = mi->mi_targets[ candidate ];
+	struct berval	mdn = BER_BVNULL;
+	struct berval	mapped_attr = op->orc_ava->aa_desc->ad_cname;
+	struct berval	mapped_value = op->orc_ava->aa_value;
+	int rc = 0, nretries = 1;
+	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.target = mt;
+	dc.conn = op->o_conn;
+	dc.rs = rs;
+	dc.ctx = "compareDN";
+
+	switch ( asyncmeta_dn_massage( &dc, &op->o_req_dn, &mdn ) ) {
+	case LDAP_UNWILLING_TO_PERFORM:
+		rs->sr_err = LDAP_UNWILLING_TO_PERFORM;
+		retcode = META_SEARCH_ERR;
+		goto doreturn;
+	default:
+		break;
+	}
+
+	/*
+	 * if attr is objectClass, try to remap the value
+	 */
+	if ( op->orc_ava->aa_desc == slap_schema.si_ad_objectClass ) {
+		asyncmeta_map( &mt->mt_rwmap.rwm_oc,
+				&op->orc_ava->aa_value,
+				&mapped_value, BACKLDAP_MAP );
+
+		if ( BER_BVISNULL( &mapped_value ) || BER_BVISEMPTY( &mapped_value ) ) {
+			rs->sr_err = LDAP_OTHER;
+			retcode = META_SEARCH_ERR;
+			goto done;
+		}
+
+	/*
+	 * else try to remap the attribute
+	 */
+	} else {
+		asyncmeta_map( &mt->mt_rwmap.rwm_at,
+			&op->orc_ava->aa_desc->ad_cname,
+			&mapped_attr, BACKLDAP_MAP );
+		if ( BER_BVISNULL( &mapped_attr ) || BER_BVISEMPTY( &mapped_attr ) ) {
+			rs->sr_err = LDAP_OTHER;
+			retcode = META_SEARCH_ERR;
+			goto done;
+		}
+
+		if ( op->orc_ava->aa_desc->ad_type->sat_syntax == slap_schema.si_syn_distinguishedName )
+		{
+			dc.ctx = "compareAttrDN";
+
+			switch ( asyncmeta_dn_massage( &dc, &op->orc_ava->aa_value, &mapped_value ) )
+			{
+			case LDAP_UNWILLING_TO_PERFORM:
+				rs->sr_err = LDAP_UNWILLING_TO_PERFORM;
+				retcode = META_SEARCH_ERR;
+				goto done;
+
+			default:
+				break;
+			}
+		}
+	}
+retry:;
+	ctrls = op->o_ctrls;
+	if ( asyncmeta_controls_add( op, rs, mc, candidate, &ctrls ) != LDAP_SUCCESS )
+	{
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		retcode = META_SEARCH_ERR;
+		goto done;
+	}
+
+	ber = ldap_build_compare_req( msc->msc_ld, mdn.bv_val, mapped_attr.bv_val, &mapped_value,
+			ctrls, NULL, &msgid);
+	if (ber) {
+		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;
+
+		switch ( rc ) {
+		case LDAP_SUCCESS:
+			retcode = META_SEARCH_CANDIDATE;
+			asyncmeta_set_msc_time(msc);
+			break;
+
+		case LDAP_SERVER_DOWN:
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+			asyncmeta_clear_one_msc(NULL, mc, candidate);
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			if ( nretries && asyncmeta_retry( op, rs, &mc, candidate, LDAP_BACK_DONTSEND ) ) {
+				nretries = 0;
+				/* if the identity changed, there might be need to re-authz */
+				(void)mi->mi_ldap_extra->controls_free( op, rs, &ctrls );
+				goto retry;
+			}
+
+		default:
+			candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+			retcode = META_SEARCH_ERR;
+		}
+	}
+done:
+	(void)mi->mi_ldap_extra->controls_free( op, rs, &ctrls );
+
+	if ( mdn.bv_val != op->o_req_dn.bv_val ) {
+		free( mdn.bv_val );
+	}
+
+	if ( op->orc_ava->aa_value.bv_val != mapped_value.bv_val ) {
+		free( mapped_value.bv_val );
+	}
+
+doreturn:;
+	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;
+	OperationBuffer opbuf;
+	bm_context_t *bc;
+	SlapReply *candidates;
+	slap_callback *cb = op->o_callback;
+
+	Debug(LDAP_DEBUG_ARGS, "==> asyncmeta_back_compare: %s\n",
+	      op->o_req_dn.bv_val, 0, 0 );
+
+	asyncmeta_new_bm_context(op, rs, &bc, mi->mi_ntargets );
+	if (bc == NULL) {
+		rs->sr_err = LDAP_OTHER;
+		asyncmeta_sender_error(op, rs, cb);
+		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) {
+		asyncmeta_sender_error(op, rs, cb);
+		asyncmeta_clear_bm_context(bc);
+		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;
+
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	rc = asyncmeta_add_message_queue(mc, bc);
+	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";
+		asyncmeta_clear_bm_context(bc);
+		asyncmeta_sender_error(op, rs, cb);
+		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=\"%ld\"\n", op->o_log_prefix, candidate , 0);
+
+		rc = asyncmeta_back_compare_start( op, rs, mc, bc, candidate);
+		if (rc == META_SEARCH_ERR) {
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+			asyncmeta_drop_bc(mc, bc);
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			asyncmeta_sender_error(op, rs, cb);
+			asyncmeta_clear_bm_context(bc);
+			goto finish;
+
+		}
+			break;
+	case META_SEARCH_NOT_CANDIDATE:
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_compare: NOT_CANDIDATE "
+		       "cnd=\"%ld\"\n", op->o_log_prefix, candidate , 0);
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+		asyncmeta_drop_bc(mc, bc);
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+		asyncmeta_sender_error(op, rs, cb);
+		asyncmeta_clear_bm_context(bc);
+		goto finish;
+
+	case META_SEARCH_NEED_BIND:
+	case META_SEARCH_CONNECTING:
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_compare: NEED_BIND "
+		       "cnd=\"%ld\" %p\n", op->o_log_prefix, candidate , &mc->mc_conns[candidate]);
+		rc = asyncmeta_dobind_init(op, rs, bc, mc, candidate);
+		if (rc == META_SEARCH_ERR) {
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+			asyncmeta_drop_bc(mc, bc);
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			asyncmeta_sender_error(op, rs, cb);
+			asyncmeta_clear_bm_context(bc);
+			goto finish;
+		}
+		break;
+	case META_SEARCH_BINDING:
+			Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_compare: BINDING "
+			       "cnd=\"%ld\" %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=\"%ldd\"\n", op->o_log_prefix, candidate , 0);
+			candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+			candidates[ candidate ].sr_type = REP_RESULT;
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+			asyncmeta_drop_bc(mc, bc);
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			asyncmeta_sender_error(op, rs, cb);
+			asyncmeta_clear_bm_context(bc);
+			goto finish;
+		default:
+			assert( 0 );
+			break;
+		}
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	asyncmeta_start_one_listener(mc, candidates, candidate);
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+finish:
+	return rs->sr_err;
+
+}

servers/slapd/back-asyncmeta/delete.c

@@ -0,0 +1,240 @@
+/* delete.c - delete request handler for back-asyncmeta */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016 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 "../../../libraries/liblber/lber-int.h"
+#include "../../../libraries/libldap/ldap-int.h"
+
+meta_search_candidate_t
+asyncmeta_back_delete_start(Operation *op,
+			    SlapReply *rs,
+			    a_metaconn_t *mc,
+			    bm_context_t *bc,
+			    int candidate)
+{
+	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, nretries = 1;
+	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.target = mt;
+	dc.conn = op->o_conn;
+	dc.rs = rs;
+	dc.ctx = "deleteDN";
+
+	if ( asyncmeta_dn_massage( &dc, &op->o_req_dn, &mdn ) ) {
+		rs->sr_err = LDAP_UNWILLING_TO_PERFORM;
+		retcode = META_SEARCH_ERR;
+		goto doreturn;
+	}
+
+retry:;
+	ctrls = op->o_ctrls;
+	if ( asyncmeta_controls_add( op, rs, mc, candidate, &ctrls ) != LDAP_SUCCESS )
+	{
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		retcode = META_SEARCH_ERR;
+		goto done;
+	}
+
+	ber = ldap_build_delete_req( msc->msc_ld, mdn.bv_val, ctrls, NULL, &msgid);
+	if (ber) {
+		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;
+
+		switch ( rc ) {
+		case LDAP_SUCCESS:
+			retcode = META_SEARCH_CANDIDATE;
+			asyncmeta_set_msc_time(msc);
+			break;
+
+		case LDAP_SERVER_DOWN:
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+			asyncmeta_clear_one_msc(NULL, mc, candidate);
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			if ( nretries && asyncmeta_retry( op, rs, &mc, candidate, LDAP_BACK_DONTSEND ) ) {
+				nretries = 0;
+				/* if the identity changed, there might be need to re-authz */
+				(void)mi->mi_ldap_extra->controls_free( op, rs, &ctrls );
+				goto retry;
+			}
+
+		default:
+			candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+			retcode = META_SEARCH_ERR;
+		}
+	}
+done:
+	(void)mi->mi_ldap_extra->controls_free( op, rs, &ctrls );
+
+	if ( mdn.bv_val != op->o_req_dn.bv_val ) {
+		free( mdn.bv_val );
+		BER_BVZERO( &mdn );
+	}
+
+doreturn:;
+	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;
+	OperationBuffer opbuf;
+	bm_context_t *bc;
+	SlapReply *candidates;
+	slap_callback *cb = op->o_callback;
+
+	Debug(LDAP_DEBUG_ARGS, "==> asyncmeta_back_delete: %s\n",
+	      op->o_req_dn.bv_val, 0, 0 );
+
+	asyncmeta_new_bm_context(op, rs, &bc, mi->mi_ntargets );
+	if (bc == NULL) {
+		rs->sr_err = LDAP_OTHER;
+		asyncmeta_sender_error(op, rs, cb);
+		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) {
+		asyncmeta_sender_error(op, rs, cb);
+		asyncmeta_clear_bm_context(bc);
+		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;
+
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	rc = asyncmeta_add_message_queue(mc, bc);
+	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";
+		asyncmeta_clear_bm_context(bc);
+		asyncmeta_sender_error(op, rs, cb);
+		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=\"%ld\"\n", op->o_log_prefix, candidate , 0);
+
+		rc = asyncmeta_back_delete_start( op, rs, mc, bc, candidate);
+		if (rc == META_SEARCH_ERR) {
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+			asyncmeta_drop_bc(mc, bc);
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			asyncmeta_sender_error(op, rs, cb);
+			asyncmeta_clear_bm_context(bc);
+			goto finish;
+
+		}
+			break;
+	case META_SEARCH_NOT_CANDIDATE:
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_delete: NOT_CANDIDATE "
+		       "cnd=\"%ld\"\n", op->o_log_prefix, candidate , 0);
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+		asyncmeta_drop_bc(mc, bc);
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+		asyncmeta_sender_error(op, rs, cb);
+		asyncmeta_clear_bm_context(bc);
+		goto finish;
+
+	case META_SEARCH_NEED_BIND:
+	case META_SEARCH_CONNECTING:
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_delete: NEED_BIND "
+		       "cnd=\"%ld\" %p\n", op->o_log_prefix, candidate , &mc->mc_conns[candidate]);
+		rc = asyncmeta_dobind_init(op, rs, bc, mc, candidate);
+		if (rc == META_SEARCH_ERR) {
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+			asyncmeta_drop_bc(mc, bc);
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			asyncmeta_sender_error(op, rs, cb);
+			asyncmeta_clear_bm_context(bc);
+			goto finish;
+		}
+		break;
+	case META_SEARCH_BINDING:
+			Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_delete: BINDING "
+			       "cnd=\"%ld\" %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=\"%ldd\"\n", op->o_log_prefix, candidate , 0);
+			candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+			candidates[ candidate ].sr_type = REP_RESULT;
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+			asyncmeta_drop_bc(mc, bc);
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			asyncmeta_sender_error(op, rs, cb);
+			asyncmeta_clear_bm_context(bc);
+			goto finish;
+		default:
+			assert( 0 );
+			break;
+		}
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	asyncmeta_start_one_listener(mc, candidates, candidate);
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+finish:
+	return rs->sr_err;
+}

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 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 * )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 * )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 = 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 = 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 );
+}

servers/slapd/back-asyncmeta/init.c

@@ -0,0 +1,509 @@
+/* init.c - initialization of a back-asyncmeta database */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016 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 "config.h"
+#include "../back-ldap/back-ldap.h"
+#include "back-asyncmeta.h"
+
+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 )
+{
+	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 = 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",
+			0, 0, 0 );
+		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 = 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 };
+	struct berval mapped;
+	int rc;
+	int msc_num, i;
+
+	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 ) )
+	{
+		snprintf( msg, msize,
+			"%s: inconsistent idassert configuration "
+			"(likely authz=\"*\" used with \"non-prescriptive\" flag)",
+			log );
+		Debug( LDAP_DEBUG_ANY, "%s (target %s)\n",
+			msg, mt->mt_uri, 0 );
+		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;
+	}
+
+	BER_BVZERO( &mapped );
+	asyncmeta_map( &mt->mt_rwmap.rwm_at,
+		&slap_schema.si_ad_entryDN->ad_cname, &mapped,
+		BACKLDAP_REMAP );
+	if ( BER_BVISNULL( &mapped ) || mapped.bv_val[0] == '\0' ) {
+		mt->mt_rep_flags |= REP_NO_ENTRYDN;
+	}
+
+	BER_BVZERO( &mapped );
+	asyncmeta_map( &mt->mt_rwmap.rwm_at,
+		&slap_schema.si_ad_subschemaSubentry->ad_cname, &mapped,
+		BACKLDAP_REMAP );
+	if ( BER_BVISNULL( &mapped ) || mapped.bv_val[0] == '\0' ) {
+		mt->mt_rep_flags |= REP_NO_SUBSCHEMA;
+	}
+	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, rc;
+
+	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",
+			0, 0, 0 );
+		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_pvt_thread_mutex_lock( &slapd_rq.rq_mutex );
+	mi->mi_task = ldap_pvt_runqueue_insert( &slapd_rq, 0,
+		asyncmeta_timeout_loop, mi, "asyncmeta_timeout_loop", be->be_suffix[0].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
+mapping_free(
+	void		*v_mapping )
+{
+	struct ldapmapping *mapping = v_mapping;
+	ch_free( mapping->src.bv_val );
+	ch_free( mapping->dst.bv_val );
+	ch_free( mapping );
+}
+
+static void
+mapping_dst_free(
+	void		*v_mapping )
+{
+	struct ldapmapping *mapping = v_mapping;
+
+	if ( BER_BVISEMPTY( &mapping->dst ) ) {
+		mapping_free( &mapping[ -1 ] );
+	}
+}
+
+void
+asyncmeta_back_map_free( struct ldapmap *lm )
+{
+	avl_free( lm->remap, mapping_dst_free );
+	avl_free( lm->map, mapping_free );
+	lm->remap = NULL;
+	lm->map = NULL;
+}
+
+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);
+		}
+		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 ( mt->mt_rwmap.rwm_rw ) {
+		rewrite_info_delete( &mt->mt_rwmap.rwm_rw );
+		if ( mt->mt_rwmap.rwm_bva_rewrite )
+			ber_bvarray_free( mt->mt_rwmap.rwm_bva_rewrite );
+	}
+	asyncmeta_back_map_free( &mt->mt_rwmap.rwm_oc );
+	asyncmeta_back_map_free( &mt->mt_rwmap.rwm_at );
+	ber_bvarray_free( mt->mt_rwmap.rwm_bva_map );
+	free( mt );
+}
+
+int
+asyncmeta_back_db_close(
+	Backend		*be,
+	ConfigReply	*cr )
+{
+	a_metainfo_t	*mi;
+
+	if ( be->be_private ) {
+		int i;
+
+		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 );
+	}
+}
+
+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 ) {
+			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 */

servers/slapd/back-asyncmeta/map.c

@@ -0,0 +1,874 @@
+/* map.c - ldap backend mapping routines */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016 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"
+
+int
+asyncmeta_mapping_cmp ( const void *c1, const void *c2 )
+{
+	struct ldapmapping *map1 = (struct ldapmapping *)c1;
+	struct ldapmapping *map2 = (struct ldapmapping *)c2;
+	int rc = map1->src.bv_len - map2->src.bv_len;
+	if (rc) return rc;
+	return ( strcasecmp( map1->src.bv_val, map2->src.bv_val ) );
+}
+
+int
+asyncmeta_mapping_dup ( void *c1, void *c2 )
+{
+	struct ldapmapping *map1 = (struct ldapmapping *)c1;
+	struct ldapmapping *map2 = (struct ldapmapping *)c2;
+
+	return ( ( strcasecmp( map1->src.bv_val, map2->src.bv_val ) == 0 ) ? -1 : 0 );
+}
+
+void
+asyncmeta_map_init ( struct ldapmap *lm, struct ldapmapping **m )
+{
+	struct ldapmapping *mapping;
+
+	assert( m != NULL );
+
+	*m = NULL;
+
+	mapping = (struct ldapmapping *)ch_calloc( 2,
+			sizeof( struct ldapmapping ) );
+	if ( mapping == NULL ) {
+		return;
+	}
+
+	ber_str2bv( "objectclass", STRLENOF("objectclass"), 1, &mapping[0].src);
+	ber_dupbv( &mapping[0].dst, &mapping[0].src );
+	mapping[1].src = mapping[0].src;
+	mapping[1].dst = mapping[0].dst;
+
+	avl_insert( &lm->map, (caddr_t)&mapping[0],
+			asyncmeta_mapping_cmp, asyncmeta_mapping_dup );
+	avl_insert( &lm->remap, (caddr_t)&mapping[1],
+			asyncmeta_mapping_cmp, asyncmeta_mapping_dup );
+	*m = mapping;
+}
+
+int
+asyncmeta_mapping ( struct ldapmap *map, struct berval *s, struct ldapmapping **m,
+	int remap )
+{
+	Avlnode *tree;
+	struct ldapmapping fmapping;
+
+	assert( m != NULL );
+
+	/* let special attrnames slip through (ITS#5760) */
+	if ( bvmatch( s, slap_bv_no_attrs )
+		|| bvmatch( s, slap_bv_all_user_attrs )
+		|| bvmatch( s, slap_bv_all_operational_attrs ) )
+	{
+		*m = NULL;
+		return 0;
+	}
+
+	if ( remap == BACKLDAP_REMAP ) {
+		tree = map->remap;
+
+	} else {
+		tree = map->map;
+	}
+
+	fmapping.src = *s;
+	*m = (struct ldapmapping *)avl_find( tree, (caddr_t)&fmapping, asyncmeta_mapping_cmp );
+	if ( *m == NULL ) {
+		return map->drop_missing;
+	}
+
+	return 0;
+}
+
+void
+asyncmeta_map ( struct ldapmap *map, struct berval *s, struct berval *bv,
+	int remap )
+{
+	struct ldapmapping *mapping;
+	int drop_missing;
+
+	/* map->map may be NULL when mapping is configured,
+	 * but map->remap can't */
+	if ( map->remap == NULL ) {
+		*bv = *s;
+		return;
+	}
+
+	BER_BVZERO( bv );
+	drop_missing = asyncmeta_mapping( map, s, &mapping, remap );
+	if ( mapping != NULL ) {
+		if ( !BER_BVISNULL( &mapping->dst ) ) {
+			*bv = mapping->dst;
+		}
+		return;
+	}
+
+	if ( !drop_missing ) {
+		*bv = *s;
+	}
+}
+
+int
+asyncmeta_map_attrs(
+		Operation *op,
+		struct ldapmap *at_map,
+		AttributeName *an,
+		int remap,
+		char ***mapped_attrs )
+{
+	int i, x, j;
+	char **na;
+	struct berval mapped;
+
+	if ( an == NULL && op->o_bd->be_extra_anlist == NULL ) {
+		*mapped_attrs = NULL;
+		return LDAP_SUCCESS;
+	}
+
+	i = 0;
+	if ( an != NULL ) {
+		for ( ; !BER_BVISNULL( &an[i].an_name ); i++ )
+			/*  */ ;
+	}
+
+	x = 0;
+	if ( op->o_bd->be_extra_anlist != NULL ) {
+		for ( ; !BER_BVISNULL( &op->o_bd->be_extra_anlist[x].an_name ); x++ )
+			/*  */ ;
+	}
+
+	assert( i > 0 || x > 0 );
+
+	na = (char **)ber_memcalloc_x( i + x + 1, sizeof(char *), op->o_tmpmemctx );
+	if ( na == NULL ) {
+		*mapped_attrs = NULL;
+		return LDAP_NO_MEMORY;
+	}
+
+	j = 0;
+	if ( i > 0 ) {
+		for ( i = 0; !BER_BVISNULL( &an[i].an_name ); i++ ) {
+			asyncmeta_map( at_map, &an[i].an_name, &mapped, remap );
+			if ( !BER_BVISNULL( &mapped ) && !BER_BVISEMPTY( &mapped ) ) {
+				na[j++] = mapped.bv_val;
+			}
+		}
+	}
+
+	if ( x > 0 ) {
+		for ( x = 0; !BER_BVISNULL( &op->o_bd->be_extra_anlist[x].an_name ); x++ ) {
+			if ( op->o_bd->be_extra_anlist[x].an_desc &&
+				ad_inlist( op->o_bd->be_extra_anlist[x].an_desc, an ) )
+			{
+				continue;
+			}
+
+			asyncmeta_map( at_map, &op->o_bd->be_extra_anlist[x].an_name, &mapped, remap );
+			if ( !BER_BVISNULL( &mapped ) && !BER_BVISEMPTY( &mapped ) ) {
+				na[j++] = mapped.bv_val;
+			}
+		}
+	}
+
+	if ( j == 0 && ( i > 0 || x > 0 ) ) {
+		na[j++] = LDAP_NO_ATTRS;
+	}
+	na[j] = NULL;
+
+	*mapped_attrs = na;
+
+	return LDAP_SUCCESS;
+}
+
+static int
+map_attr_value(
+		a_dncookie		*dc,
+		AttributeDescription 	*ad,
+		struct berval		*mapped_attr,
+		struct berval		*value,
+		struct berval		*mapped_value,
+		int			remap,
+		void			*memctx )
+{
+	struct berval		vtmp;
+	int			freeval = 0;
+
+	asyncmeta_map( &dc->target->mt_rwmap.rwm_at, &ad->ad_cname, mapped_attr, remap );
+	if ( BER_BVISNULL( mapped_attr ) || BER_BVISEMPTY( mapped_attr ) ) {
+#if 0
+		/*
+		 * FIXME: are we sure we need to search oc_map if at_map fails?
+		 */
+		asyncmeta_map( &dc->target->mt_rwmap.rwm_oc, &ad->ad_cname, mapped_attr, remap );
+		if ( BER_BVISNULL( mapped_attr ) || BER_BVISEMPTY( mapped_attr ) ) {
+			*mapped_attr = ad->ad_cname;
+		}
+#endif
+		if ( dc->target->mt_rwmap.rwm_at.drop_missing ) {
+			return -1;
+		}
+
+		*mapped_attr = ad->ad_cname;
+	}
+
+	if ( value == NULL ) {
+		return 0;
+	}
+
+	if ( ad->ad_type->sat_syntax == slap_schema.si_syn_distinguishedName )
+	{
+		a_dncookie fdc = *dc;
+
+		fdc.ctx = "searchFilterAttrDN";
+
+		switch ( asyncmeta_dn_massage( &fdc, value, &vtmp ) ) {
+		case LDAP_SUCCESS:
+			if ( vtmp.bv_val != value->bv_val ) {
+				freeval = 1;
+			}
+			break;
+
+		case LDAP_UNWILLING_TO_PERFORM:
+			return -1;
+
+		case LDAP_OTHER:
+			return -1;
+		}
+
+	} else if ( ad->ad_type->sat_equality &&
+		ad->ad_type->sat_equality->smr_usage & SLAP_MR_MUTATION_NORMALIZER )
+	{
+		if ( ad->ad_type->sat_equality->smr_normalize(
+			(SLAP_MR_DENORMALIZE|SLAP_MR_VALUE_OF_ASSERTION_SYNTAX),
+			NULL, NULL, value, &vtmp, memctx ) )
+		{
+			return -1;
+		}
+		freeval = 2;
+
+	} else if ( ad == slap_schema.si_ad_objectClass || ad == slap_schema.si_ad_structuralObjectClass ) {
+		asyncmeta_map( &dc->target->mt_rwmap.rwm_oc, value, &vtmp, remap );
+		if ( BER_BVISNULL( &vtmp ) || BER_BVISEMPTY( &vtmp ) ) {
+			vtmp = *value;
+		}
+
+	} else {
+		vtmp = *value;
+	}
+
+	filter_escape_value_x( &vtmp, mapped_value, memctx );
+
+	switch ( freeval ) {
+	case 1:
+		ber_memfree( vtmp.bv_val );
+		break;
+	case 2:
+		ber_memfree_x( vtmp.bv_val, memctx );
+		break;
+	}
+
+	return 0;
+}
+
+static int
+asyncmeta_int_filter_map_rewrite(
+		a_dncookie		*dc,
+		Filter			*f,
+		struct berval	*fstr,
+		int				remap,
+		void			*memctx )
+{
+	int		i;
+	Filter		*p;
+	struct berval	atmp,
+			vtmp,
+			*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( "(&)" ),
+#if 0
+			/* no longer needed; preserved for completeness */
+			ber_bvundefined = BER_BVC( "(?=undefined)" ),
+#endif
+			ber_bverror = BER_BVC( "(?=error)" ),
+			ber_bvunknown = BER_BVC( "(?=unknown)" ),
+			ber_bvnone = BER_BVC( "(?=none)" );
+	ber_len_t	len;
+
+	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 ( map_attr_value( dc, f->f_av_desc, &atmp,
+					&f->f_av_value, &vtmp, remap, memctx ) )
+		{
+			goto computed;
+		}
+
+		fstr->bv_len = atmp.bv_len + vtmp.bv_len
+			+ ( sizeof("(=)") - 1 );
+		fstr->bv_val = ber_memalloc_x( fstr->bv_len + 1, memctx );
+
+		snprintf( fstr->bv_val, fstr->bv_len + 1, "(%s=%s)",
+			atmp.bv_val, vtmp.bv_len ? vtmp.bv_val : "" );
+
+		ber_memfree_x( vtmp.bv_val, memctx );
+		break;
+
+	case LDAP_FILTER_GE:
+		if ( map_attr_value( dc, f->f_av_desc, &atmp,
+					&f->f_av_value, &vtmp, remap, memctx ) )
+		{
+			goto computed;
+		}
+
+		fstr->bv_len = atmp.bv_len + vtmp.bv_len
+			+ ( sizeof("(>=)") - 1 );
+		fstr->bv_val = ber_memalloc_x( fstr->bv_len + 1, memctx );
+
+		snprintf( fstr->bv_val, fstr->bv_len + 1, "(%s>=%s)",
+			atmp.bv_val, vtmp.bv_len ? vtmp.bv_val : "" );
+
+		ber_memfree_x( vtmp.bv_val, memctx );
+		break;
+
+	case LDAP_FILTER_LE:
+		if ( map_attr_value( dc, f->f_av_desc, &atmp,
+					&f->f_av_value, &vtmp, remap, memctx ) )
+		{
+			goto computed;
+		}
+
+		fstr->bv_len = atmp.bv_len + vtmp.bv_len
+			+ ( sizeof("(<=)") - 1 );
+		fstr->bv_val = ber_memalloc_x( fstr->bv_len + 1, memctx );
+
+		snprintf( fstr->bv_val, fstr->bv_len + 1, "(%s<=%s)",
+			atmp.bv_val, vtmp.bv_len ? vtmp.bv_val : "" );
+
+		ber_memfree_x( vtmp.bv_val, memctx );
+		break;
+
+	case LDAP_FILTER_APPROX:
+		if ( map_attr_value( dc, f->f_av_desc, &atmp,
+					&f->f_av_value, &vtmp, remap, memctx ) )
+		{
+			goto computed;
+		}
+
+		fstr->bv_len = atmp.bv_len + vtmp.bv_len
+			+ ( sizeof("(~=)") - 1 );
+		fstr->bv_val = ber_memalloc_x( fstr->bv_len + 1, memctx );
+
+		snprintf( fstr->bv_val, fstr->bv_len + 1, "(%s~=%s)",
+			atmp.bv_val, vtmp.bv_len ? vtmp.bv_val : "" );
+
+		ber_memfree_x( vtmp.bv_val, memctx );
+		break;
+
+	case LDAP_FILTER_SUBSTRINGS:
+		if ( map_attr_value( dc, f->f_sub_desc, &atmp,
+					NULL, NULL, remap, memctx ) )
+		{
+			goto computed;
+		}
+
+		/* cannot be a DN ... */
+
+		fstr->bv_len = atmp.bv_len + ( STRLENOF( "(=*)" ) );
+		fstr->bv_val = ber_memalloc_x( fstr->bv_len + 128, memctx ); /* FIXME: why 128 ? */
+
+		snprintf( fstr->bv_val, fstr->bv_len + 1, "(%s=*)",
+			atmp.bv_val );
+
+		if ( !BER_BVISNULL( &f->f_sub_initial ) ) {
+			len = fstr->bv_len;
+
+			filter_escape_value_x( &f->f_sub_initial, &vtmp, memctx );
+
+			fstr->bv_len += vtmp.bv_len;
+			fstr->bv_val = ber_memrealloc_x( fstr->bv_val, fstr->bv_len + 1, memctx );
+
+			snprintf( &fstr->bv_val[len - 2], vtmp.bv_len + 3,
+				/* "(attr=" */ "%s*)",
+				vtmp.bv_len ? vtmp.bv_val : "" );
+
+			ber_memfree_x( vtmp.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], &vtmp, memctx );
+
+				fstr->bv_len += vtmp.bv_len + 1;
+				fstr->bv_val = ber_memrealloc_x( fstr->bv_val, fstr->bv_len + 1, memctx );
+
+				snprintf( &fstr->bv_val[len - 1], vtmp.bv_len + 3,
+					/* "(attr=[init]*[any*]" */ "%s*)",
+					vtmp.bv_len ? vtmp.bv_val : "" );
+				ber_memfree_x( vtmp.bv_val, memctx );
+			}
+		}
+
+		if ( !BER_BVISNULL( &f->f_sub_final ) ) {
+			len = fstr->bv_len;
+
+			filter_escape_value_x( &f->f_sub_final, &vtmp, memctx );
+
+			fstr->bv_len += vtmp.bv_len;
+			fstr->bv_val = ber_memrealloc_x( fstr->bv_val, fstr->bv_len + 1, memctx );
+
+			snprintf( &fstr->bv_val[len - 1], vtmp.bv_len + 3,
+				/* "(attr=[init*][any*]" */ "%s)",
+				vtmp.bv_len ? vtmp.bv_val : "" );
+
+			ber_memfree_x( vtmp.bv_val, memctx );
+		}
+
+		break;
+
+	case LDAP_FILTER_PRESENT:
+		if ( map_attr_value( dc, f->f_desc, &atmp,
+					NULL, NULL, remap, memctx ) )
+		{
+			goto computed;
+		}
+
+		fstr->bv_len = atmp.bv_len + ( STRLENOF( "(=*)" ) );
+		fstr->bv_val = ber_memalloc_x( fstr->bv_len + 1, memctx );
+
+		snprintf( fstr->bv_val, fstr->bv_len + 1, "(%s=*)",
+			atmp.bv_val );
+		break;
+
+	case LDAP_FILTER_AND:
+	case LDAP_FILTER_OR:
+	case LDAP_FILTER_NOT:
+		fstr->bv_len = STRLENOF( "(%)" );
+		fstr->bv_val = ber_memalloc_x( 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_filter_map_rewrite( dc, p, &vtmp, remap, memctx );
+			if ( rc != LDAP_SUCCESS ) {
+				return rc;
+			}
+
+			fstr->bv_len += vtmp.bv_len;
+			fstr->bv_val = ber_memrealloc_x( 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 ) {
+			if ( map_attr_value( dc, f->f_mr_desc, &atmp,
+						&f->f_mr_value, &vtmp, remap, memctx ) )
+			{
+				goto computed;
+			}
+
+		} else {
+			BER_BVSTR( &atmp, "" );
+			filter_escape_value_x( &f->f_mr_value, &vtmp, 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 ) +
+			vtmp.bv_len + ( STRLENOF( "(:=)" ) );
+		fstr->bv_val = ber_memalloc_x( 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 : "",
+			vtmp.bv_len ? vtmp.bv_val : "" );
+		ber_memfree_x( vtmp.bv_val, memctx );
+		break;
+
+	case SLAPD_FILTER_COMPUTED:
+		switch ( f->f_result ) {
+		/* FIXME: treat UNDEFINED as FALSE */
+		case SLAPD_COMPARE_UNDEFINED:
+computed:;
+			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;
+}
+
+int
+asyncmeta_filter_map_rewrite(
+		a_dncookie		*dc,
+		Filter			*f,
+		struct berval	*fstr,
+		int				remap,
+		void			*memctx )
+{
+	int		rc;
+	a_dncookie	fdc;
+	struct berval	ftmp;
+	static char	*dmy = "";
+
+	rc = asyncmeta_int_filter_map_rewrite( dc, f, fstr, remap, memctx );
+
+	if ( rc != LDAP_SUCCESS ) {
+		return rc;
+	}
+
+	fdc = *dc;
+	ftmp = *fstr;
+
+	fdc.ctx = "searchFilter";
+
+	switch ( rewrite_session( fdc.target->mt_rwmap.rwm_rw, fdc.ctx,
+				( !BER_BVISEMPTY( &ftmp ) ? ftmp.bv_val : dmy ),
+				fdc.conn, &fstr->bv_val ) )
+	{
+	case REWRITE_REGEXEC_OK:
+		if ( !BER_BVISNULL( fstr ) ) {
+			fstr->bv_len = strlen( fstr->bv_val );
+
+		} else {
+			*fstr = ftmp;
+		}
+		Debug( LDAP_DEBUG_ARGS,
+			"[rw] %s: \"%s\" -> \"%s\"\n",
+			fdc.ctx, BER_BVISNULL( &ftmp ) ? "" : ftmp.bv_val,
+			BER_BVISNULL( fstr ) ? "" : fstr->bv_val );
+		rc = LDAP_SUCCESS;
+		break;
+
+	case REWRITE_REGEXEC_UNWILLING:
+		if ( fdc.rs ) {
+			fdc.rs->sr_err = LDAP_UNWILLING_TO_PERFORM;
+			fdc.rs->sr_text = "Operation not allowed";
+		}
+		rc = LDAP_UNWILLING_TO_PERFORM;
+		break;
+
+	case REWRITE_REGEXEC_ERR:
+		if ( fdc.rs ) {
+			fdc.rs->sr_err = LDAP_OTHER;
+			fdc.rs->sr_text = "Rewrite error";
+		}
+		rc = LDAP_OTHER;
+		break;
+	}
+
+	if ( fstr->bv_val == dmy ) {
+		BER_BVZERO( fstr );
+
+	} else if ( fstr->bv_val != ftmp.bv_val ) {
+		/* NOTE: need to realloc mapped filter on slab
+		 * and free the original one, until librewrite
+		 * becomes slab-aware
+		 */
+		ber_dupbv_x( &ftmp, fstr, memctx );
+		ch_free( fstr->bv_val );
+		*fstr = ftmp;
+	}
+
+	return rc;
+}
+
+int
+asyncmeta_referral_result_rewrite(
+	a_dncookie		*dc,
+	BerVarray		a_vals,
+	void			*memctx
+)
+{
+	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 );
+
+		rc = asyncmeta_dn_massage( dc, &olddn, &dn );
+		switch ( rc ) {
+		case LDAP_UNWILLING_TO_PERFORM:
+			/*
+			 * FIXME: need to check if it may be considered
+			 * legal to trim values when adding/modifying;
+			 * it should be when searching (e.g. ACLs).
+			 */
+			ber_memfree( a_vals[ i ].bv_val );
+			if ( last > i ) {
+				a_vals[ i ] = a_vals[ last ];
+			}
+			BER_BVZERO( &a_vals[ last ] );
+			last--;
+			i--;
+			break;
+
+		default:
+			/* leave attr untouched if massage failed */
+			if ( !BER_BVISNULL( &dn ) && olddn.bv_val != dn.bv_val )
+			{
+				char	*newurl;
+
+				ludp->lud_dn = dn.bv_val;
+				newurl = ldap_url_desc2str( ludp );
+				free( dn.bv_val );
+				if ( newurl == NULL ) {
+					/* FIXME: leave attr untouched
+					 * even if ldap_url_desc2str failed...
+					 */
+					break;
+				}
+
+				ber_memfree_x( a_vals[ i ].bv_val, memctx );
+				ber_str2bv_x( newurl, 0, 1, &a_vals[ i ], memctx );
+				ber_memfree( newurl );
+				ludp->lud_dn = olddn.bv_val;
+			}
+			break;
+		}
+
+		ldap_free_urldesc( ludp );
+	}
+
+	return 0;
+}
+
+/*
+ * I don't like this much, but we need two different
+ * functions because different heap managers may be
+ * in use in back-ldap/meta to reduce the amount of
+ * calls to malloc routines, and some of the free()
+ * routines may be macros with args
+ */
+int
+asyncmeta_dnattr_rewrite(
+	a_dncookie		*dc,
+	BerVarray		a_vals
+)
+{
+	struct berval	bv;
+	int		i, last;
+
+	assert( a_vals != NULL );
+
+	for ( last = 0; !BER_BVISNULL( &a_vals[last] ); last++ )
+		;
+	last--;
+
+	for ( i = 0; !BER_BVISNULL( &a_vals[i] ); i++ ) {
+		switch ( asyncmeta_dn_massage( dc, &a_vals[i], &bv ) ) {
+		case LDAP_UNWILLING_TO_PERFORM:
+			/*
+			 * FIXME: need to check if it may be considered
+			 * legal to trim values when adding/modifying;
+			 * it should be when searching (e.g. ACLs).
+			 */
+			ch_free( a_vals[i].bv_val );
+			if ( last > i ) {
+				a_vals[i] = a_vals[last];
+			}
+			BER_BVZERO( &a_vals[last] );
+			last--;
+			break;
+
+		default:
+			/* leave attr untouched if massage failed */
+			if ( !BER_BVISNULL( &bv ) && bv.bv_val != a_vals[i].bv_val ) {
+				ch_free( a_vals[i].bv_val );
+				a_vals[i] = bv;
+			}
+			break;
+		}
+	}
+
+	return 0;
+}
+
+int
+asyncmeta_dnattr_result_rewrite(
+	a_dncookie		*dc,
+	BerVarray		a_vals
+)
+{
+	struct berval	bv;
+	int		i, last;
+
+	assert( a_vals != NULL );
+
+	for ( last = 0; !BER_BVISNULL( &a_vals[last] ); last++ )
+		;
+	last--;
+
+	for ( i = 0; !BER_BVISNULL( &a_vals[i] ); i++ ) {
+		switch ( asyncmeta_dn_massage( dc, &a_vals[i], &bv ) ) {
+		case LDAP_UNWILLING_TO_PERFORM:
+			/*
+			 * FIXME: need to check if it may be considered
+			 * legal to trim values when adding/modifying;
+			 * it should be when searching (e.g. ACLs).
+			 */
+			ber_memfree( a_vals[i].bv_val );
+			if ( last > i ) {
+				a_vals[i] = a_vals[last];
+			}
+			BER_BVZERO( &a_vals[last] );
+			last--;
+			break;
+
+		default:
+			/* leave attr untouched if massage failed */
+			if ( !BER_BVISNULL( &bv ) && a_vals[i].bv_val != bv.bv_val ) {
+				ber_memfree( a_vals[i].bv_val );
+				a_vals[i] = bv;
+			}
+			break;
+		}
+	}
+
+	return 0;
+}

servers/slapd/back-asyncmeta/message_queue.c

@@ -0,0 +1,545 @@
+/* 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 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"
+
+
+LDAPControl **asyncmeta_copy_controls(Operation *op)
+{
+	LDAPControl **new_controls = NULL;
+	LDAPControl **c;
+	LDAPControl  *tmp_ctl = NULL;
+	int i, length = 1;
+
+
+	if (op->o_ctrls == NULL) {
+		return NULL;
+	}
+	for (c = op->o_ctrls; *c != NULL; c++) {
+		length++;
+	}
+
+	new_controls = op->o_tmpalloc( sizeof(LDAPControl*)*length, op->o_tmpmemctx );
+	for (i = 0; i < length-1; i ++) {
+		new_controls[i] = op->o_tmpalloc( sizeof(LDAPControl), op->o_tmpmemctx );
+		if (op->o_ctrls[i]->ldctl_value.bv_len > 0) {
+			ber_dupbv_x( &new_controls[i]->ldctl_value, &op->o_ctrls[i]->ldctl_value, op->o_tmpmemctx);
+		}
+		if (op->o_ctrls[i]->ldctl_oid) {
+			new_controls[i]->ldctl_oid = ber_strdup_x(op->o_ctrls[i]->ldctl_oid, op->o_tmpmemctx);
+		}
+		new_controls[i]->ldctl_iscritical = op->o_ctrls[i]->ldctl_iscritical;
+	}
+	new_controls[length-1] = NULL;
+	return new_controls;
+}
+
+static
+void asyncmeta_free_op_controls(Operation *op)
+{
+	LDAPControl **c;
+	for (c = op->o_ctrls; *c != NULL; c++) {
+		if ((*c)->ldctl_value.bv_len > 0) {
+			free((*c)->ldctl_value.bv_val);
+		}
+		if ((*c)->ldctl_oid) {
+			free((*c)->ldctl_oid);
+		}
+		free(*c);
+	}
+	free(op->o_ctrls);
+}
+
+
+static
+Modifications* asyncmeta_copy_modlist(Operation *op, Modifications *modlist)
+{
+	Modifications *ml;
+	Modifications *new_mods = NULL;
+	for ( ml = modlist; ml != NULL; ml = ml->sml_next ) {
+		Modifications *mod = op->o_tmpalloc( sizeof( Modifications ), op->o_tmpmemctx );
+		*mod = *ml;
+		if ( ml->sml_values ) {
+				ber_bvarray_dup_x( &mod->sml_values, ml->sml_values, op->o_tmpmemctx );
+				if ( ml->sml_nvalues ) {
+					ber_bvarray_dup_x( &mod->sml_nvalues, ml->sml_nvalues, op->o_tmpmemctx );
+				}
+			}
+		mod->sml_next = NULL;
+		if (new_mods == NULL) {
+			new_mods = mod;
+		} else {
+			new_mods->sml_next = mod;
+		}
+	}
+	return new_mods;
+}
+
+Operation *asyncmeta_copy_op(Operation *op)
+{
+	const char	*text;
+	int rc;
+	char txtbuf[SLAP_TEXT_BUFLEN];
+	size_t textlen = sizeof txtbuf;
+	Entry *e;
+	Operation *new_op = op->o_tmpcalloc( 1, sizeof(OperationBuffer), op->o_tmpmemctx );
+	*new_op = *op;
+	new_op->o_hdr = &((OperationBuffer *) new_op)->ob_hdr;
+	*(new_op->o_hdr) = *(op->o_hdr);
+	new_op->o_controls = ((OperationBuffer *) new_op)->ob_controls;
+	new_op->o_callback = op->o_callback;
+	new_op->o_ber = NULL;
+	new_op->o_bd = op->o_bd->bd_self;
+
+	ber_dupbv_x( &new_op->o_req_dn, &op->o_req_dn, op->o_tmpmemctx );
+	ber_dupbv_x( &new_op->o_req_ndn, &op->o_req_ndn, op->o_tmpmemctx );
+	op->o_callback = NULL;
+
+	if (op->o_ndn.bv_len > 0) {
+		ber_dupbv_x( &new_op->o_ndn, &op->o_ndn, op->o_tmpmemctx );
+	}
+	if (op->o_dn.bv_len > 0) {
+		ber_dupbv_x( &new_op->o_dn, &op->o_dn, op->o_tmpmemctx );
+	}
+
+	new_op->o_ctrls = asyncmeta_copy_controls(op);
+	switch (op->o_tag) {
+	case LDAP_REQ_SEARCH:
+	{
+		AttributeName *at_names;
+		int i;
+		for (i=0; op->ors_attrs && !BER_BVISNULL( &op->ors_attrs[i].an_name ); i++);
+		if (i > 0) {
+			at_names = op->o_tmpcalloc( i+1, sizeof( AttributeName ), op->o_tmpmemctx );
+			at_names[i].an_name.bv_len = 0;
+			i--;
+			for (i; i >= 0; i--) {
+				at_names[i] = op->ors_attrs[i];
+				ber_dupbv_x( &at_names[i].an_name, &op->ors_attrs[i].an_name, op->o_tmpmemctx );
+			}
+		} else {
+			at_names = NULL;
+		}
+		ber_dupbv_x( &new_op->ors_filterstr, &op->ors_filterstr, op->o_tmpmemctx );
+		new_op->ors_filter = filter_dup( op->ors_filter, op->o_tmpmemctx );
+		new_op->ors_attrs = at_names;
+	}
+	break;
+	case LDAP_REQ_ADD:
+	{
+		slap_entry2mods(op->ora_e, &new_op->ora_modlist, &text, txtbuf, textlen);
+		e = entry_alloc();
+		new_op->ora_e = e;
+		ber_dupbv_x( &e->e_name, &op->o_req_dn, op->o_tmpmemctx );
+		ber_dupbv_x( &e->e_nname, &op->o_req_ndn, op->o_tmpmemctx );
+		rc = slap_mods2entry( new_op->ora_modlist, &new_op->ora_e, 1, 0, &text, txtbuf, textlen);
+	}
+	break;
+	case LDAP_REQ_MODIFY:
+	{
+		new_op->orm_modlist = asyncmeta_copy_modlist(op, op->orm_modlist);
+	}
+	break;
+	case LDAP_REQ_COMPARE:
+		new_op->orc_ava = (AttributeAssertion *)ch_calloc( 1, sizeof( AttributeAssertion ));
+		*new_op->orc_ava = *op->orc_ava;
+		if ( !BER_BVISNULL( &op->orc_ava->aa_value ) ) {
+			ber_dupbv_x( &new_op->orc_ava->aa_value,  &op->orc_ava->aa_value, op->o_tmpmemctx);
+		}
+		break;
+	case LDAP_REQ_MODRDN:
+
+		if (op->orr_newrdn.bv_len > 0) {
+			ber_dupbv_x( &new_op->orr_newrdn, &op->orr_newrdn, op->o_tmpmemctx );
+		}
+		if (op->orr_nnewrdn.bv_len > 0) {
+			ber_dupbv_x( &new_op->orr_nnewrdn, &op->orr_nnewrdn, op->o_tmpmemctx );
+		}
+		if (op->orr_newSup != NULL) {
+			new_op->orr_newSup = op->o_tmpalloc( sizeof( struct berval ), op->o_tmpmemctx );
+			new_op->orr_newSup->bv_len = 0;
+			if (op->orr_newSup->bv_len > 0) {
+				ber_dupbv_x( new_op->orr_newSup, op->orr_newSup, op->o_tmpmemctx );
+			}
+		}
+
+		if (op->orr_nnewSup != NULL) {
+			new_op->orr_nnewSup = op->o_tmpalloc( sizeof( struct berval ), op->o_tmpmemctx );
+			new_op->orr_nnewSup->bv_len = 0;
+			if (op->orr_nnewSup->bv_len > 0) {
+				ber_dupbv_x( new_op->orr_nnewSup, op->orr_nnewSup, op->o_tmpmemctx );
+			}
+		}
+		new_op->orr_modlist = asyncmeta_copy_modlist(op, op->orr_modlist);
+		break;
+	case LDAP_REQ_DELETE:
+	default:
+		break;
+	}
+	return new_op;
+}
+
+
+typedef struct listptr {
+	void *reserved;
+	struct listptr *next;
+} listptr;
+
+typedef struct listhead {
+	struct listptr *list;
+	int cnt;
+} listhead;
+
+static void *asyncmeta_memctx_destroy(void *key, void *data)
+{
+	listhead *lh = data;
+	listptr *lp;
+	while (lp = lh->list) {
+		lh->list = lp->next;
+		slap_sl_mem_destroy((void *)1, lp);
+	}
+	ch_free(lh);
+}
+
+#ifndef LH_MAX
+#define LH_MAX	16
+#endif
+
+static void *asyncmeta_memctx_get(void *threadctx)
+{
+	listhead *lh = NULL;
+	listptr *lp = NULL;
+	ldap_pvt_thread_pool_getkey(threadctx, asyncmeta_memctx_get, &lh, NULL);
+	if (!lh) {
+		lh = ch_malloc(sizeof(listhead));
+		lh->cnt = 0;
+		lh->list = NULL;
+		ldap_pvt_thread_pool_setkey(threadctx, asyncmeta_memctx_get, lh, asyncmeta_memctx_destroy, NULL, NULL);
+	}
+	if (lh->list) {
+		lp = lh->list;
+		lh->list = lp->next;
+		lh->cnt--;
+		slap_sl_mem_setctx(threadctx, lp);
+	}
+	return slap_sl_mem_create(SLAP_SLAB_SIZE, SLAP_SLAB_STACK, threadctx, 1);
+}
+
+static void asyncmeta_memctx_put(void *threadctx, void *memctx)
+{
+	listhead *lh = NULL;
+	ldap_pvt_thread_pool_getkey(threadctx, asyncmeta_memctx_get, &lh, NULL);
+	if (!lh) {
+		lh = ch_malloc(sizeof(listhead));
+		lh->cnt = 0;
+		lh->list = NULL;
+		ldap_pvt_thread_pool_setkey(threadctx, asyncmeta_memctx_get, lh, asyncmeta_memctx_destroy, NULL, NULL);
+	}
+	if (lh->cnt < LH_MAX) {
+		listptr *lp = memctx;
+		lp->next = lh->list;
+		lh->list = lp;
+		lh->cnt++;
+	} else {
+		slap_sl_mem_destroy((void *)1, memctx);
+	}
+}
+
+int asyncmeta_new_bm_context(Operation *op, SlapReply *rs, bm_context_t **new_bc, int ntargets)
+{
+	void *oldctx = op->o_tmpmemctx;
+
+	/* prevent old memctx from being destroyed */
+	slap_sl_mem_setctx(op->o_threadctx, NULL);
+	/* create new memctx */
+	op->o_tmpmemctx = asyncmeta_memctx_get( op->o_threadctx );
+	*new_bc = op->o_tmpcalloc( 1, sizeof( bm_context_t ), op->o_tmpmemctx );
+
+	(*new_bc)->op = asyncmeta_copy_op(op);
+	(*new_bc)->candidates = op->o_tmpcalloc(ntargets, sizeof(SlapReply),op->o_tmpmemctx);
+	/* restore original memctx */
+	slap_sl_mem_setctx(op->o_threadctx, oldctx);
+	op->o_tmpmemctx = oldctx;
+	return LDAP_SUCCESS;
+}
+
+void asyncmeta_free_op(Operation *op)
+{
+	assert (op != NULL);
+	switch (op->o_tag) {
+	case LDAP_REQ_SEARCH:
+		if (op->ors_filterstr.bv_len != 0) {
+			free(op->ors_filterstr.bv_val);
+		}
+		if (op->ors_filter) {
+			filter_free(op->ors_filter);
+		}
+		if (op->ors_attrs) {
+			free(op->ors_attrs);
+		}
+		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_newrdn.bv_len > 0) {
+			free(op->orr_newrdn.bv_val);
+		}
+		if (op->orr_nnewrdn.bv_len > 0) {
+			free(op->orr_nnewrdn.bv_val);
+		}
+
+		if (op->orr_nnewSup != NULL ) {
+			if (op->orr_nnewSup->bv_len > 0) {
+				free(op->orr_nnewSup->bv_val);
+			}
+			free (op->orr_nnewSup);
+		}
+
+		if (op->orr_newSup != NULL ) {
+			if (op->orr_newSup->bv_len > 0) {
+				free(op->orr_newSup->bv_val);
+			}
+			free (op->orr_newSup);
+		}
+
+		if ( op->orr_modlist != NULL ) {
+			slap_mods_free(op->orr_modlist, 1 );
+		}
+		break;
+	case LDAP_REQ_COMPARE:
+		if ( !BER_BVISNULL( &op->orc_ava->aa_value ) ) {
+			free(op->orc_ava->aa_value.bv_val);
+		}
+		free(op->orc_ava);
+		break;
+	case LDAP_REQ_DELETE:
+		break;
+	default:
+		Debug( LDAP_DEBUG_TRACE, "==> asyncmeta_free_op : other message type",
+	       0, 0, 0 );
+	}
+
+	if (op->o_ctrls != NULL) {
+		asyncmeta_free_op_controls(op);
+	}
+	if (op->o_ndn.bv_len > 0) {
+		free(op->o_ndn.bv_val);
+	}
+	if (op->o_dn.bv_len > 0) {
+		free( op->o_dn.bv_val );
+	}
+	if (op->o_req_dn.bv_len > 0) {
+		free(op->o_req_dn.bv_val);
+	}
+	if (op->o_req_dn.bv_len > 0) {
+		free(op->o_req_ndn.bv_val);
+	}
+	free(op);
+}
+
+
+
+
+void asyncmeta_clear_bm_context(bm_context_t *bc)
+{
+
+	Operation *op = bc->op;
+#if 0
+	bm_candidates_t  *cl;
+	a_metainfo_t	*mi;
+	int i = 0;
+	if (bmc == NULL) {
+		return;
+	} else if (bmc->cl == NULL) {
+		free(bmc);
+		return;
+	}
+	cl = bmc->cl;
+	op = cl->op;
+	switch (op->o_tag) {
+	case LDAP_REQ_SEARCH:
+		break;
+	case LDAP_REQ_ADD:
+		if ( (bmc->mdn.bv_len != 0) &&
+		     (bmc->mdn.bv_val != op->o_req_dn.bv_val) ) {
+			free( bmc->mdn.bv_val );
+		}
+
+		if (bmc->data.add_d.attrs != NULL )  {
+			while (bmc->data.add_d.attrs[i] != NULL) {
+				free( bmc->data.add_d.attrs[i]->mod_bvalues );
+				free( bmc->data.add_d.attrs[i] );
+				i++;
+			}
+			free( bmc->data.add_d.attrs );
+			}
+		break;
+	case LDAP_REQ_MODIFY:
+		if ( bmc->mdn.bv_val != op->o_req_dn.bv_val ) {
+			free( bmc->mdn.bv_val );
+		}
+		if ( bmc->data.mod_d.modv != NULL ) {
+			for ( i = 0; bmc->data.mod_d.modv[ i ]; i++ ) {
+				free( bmc->data.mod_d.modv[ i ]->mod_bvalues );
+			}
+		}
+		free( bmc->data.mod_d.mods );
+		free( bmc->data.mod_d.modv );
+
+		break;
+	case LDAP_REQ_MODRDN:
+		if ( bmc->mdn.bv_val != op->o_req_dn.bv_val ) {
+			free( bmc->mdn.bv_val );
+		}
+
+		if ( bmc->data.modrdn_d.newSuperior.bv_len != 0 &&
+		     bmc->data.modrdn_d.newSuperior.bv_val != op->orr_newSup->bv_val )
+		{
+			free( bmc->data.modrdn_d.newSuperior.bv_val );
+
+		}
+
+		if ( bmc->data.modrdn_d.newrdn.bv_len != 0 &&
+		     bmc->data.modrdn_d.newrdn.bv_val != op->orr_newrdn.bv_val )
+		{
+			free( bmc->data.modrdn_d.newrdn.bv_val );
+
+		}
+		break;
+	case LDAP_REQ_COMPARE:
+		if ( bmc->mdn.bv_val != op->o_req_dn.bv_val ) {
+			free( bmc->mdn.bv_val );
+		}
+		if ( op->orc_ava->aa_value.bv_val != bmc->data.comp_d.mapped_value.bv_val ) {
+			free( bmc->data.comp_d.mapped_value.bv_val );
+			}
+		break;
+	case LDAP_REQ_DELETE:
+		if ( bmc->mdn.bv_val != op->o_req_dn.bv_val ) {
+			free( bmc->mdn.bv_val );
+		}
+		break;
+	default:
+		Debug( LDAP_DEBUG_TRACE, "==> asyncmeta_clear_bm_context: other message type",
+	       0, 0, 0 );
+	}
+	if (bmc->dc != NULL) {
+		free (bmc->dc);
+	}
+	free(bmc);
+
+	if (clear_cl > 0) {
+		asyncmeta_free_candidate_list(cl, lock);
+		Debug( LDAP_DEBUG_TRACE, "==> asyncmeta_clear_bm_context: free_cl_list\n",
+	       0, 0, 0 );
+	}
+#else
+	asyncmeta_memctx_put(op->o_threadctx, op->o_tmpmemctx);
+#endif
+}
+
+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 );
+
+	if (mc->pending_ops >= max_pending_ops) {
+		return LDAP_BUSY;
+	}
+
+	LDAP_SLIST_INSERT_HEAD( &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_SLIST_FOREACH( om, &mc->mc_om_list, bc_next ) {
+		if (om == bc) {
+			LDAP_SLIST_REMOVE(&mc->mc_om_list, om, bm_context_t, bc_next);
+			mc->pending_ops--;
+			break;
+		}
+	}
+}
+
+bm_context_t *
+asyncmeta_find_message(ber_int_t msgid, a_metaconn_t *mc, int candidate)
+{
+	bm_context_t *om;
+	LDAP_SLIST_FOREACH( om, &mc->mc_om_list, bc_next ) {
+		if (om->candidates[candidate].sr_msgid == msgid) {
+			break;
+		}
+	}
+	return om;
+}
+
+
+
+bm_context_t *
+asyncmeta_find_message_by_opmsguid (ber_int_t msgid, a_metaconn_t *mc, int remove)
+{
+	bm_context_t *om;
+	LDAP_SLIST_FOREACH( om, &mc->mc_om_list, bc_next ) {
+		if (om->op->o_msgid == msgid) {
+			break;
+		}
+	}
+	if (remove && om) {
+		LDAP_SLIST_REMOVE(&mc->mc_om_list, om, bm_context_t, bc_next);
+		mc->pending_ops--;
+	}
+	return om;
+}

servers/slapd/back-asyncmeta/modify.c

@@ -0,0 +1,369 @@
+/* modify.c - modify request handler for back-asyncmeta */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016 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 "../../../libraries/liblber/lber-int.h"
+#include "../../../libraries/libldap/ldap-int.h"
+
+meta_search_candidate_t
+asyncmeta_back_modify_start(Operation *op,
+			    SlapReply *rs,
+			    a_metaconn_t *mc,
+			    bm_context_t *bc,
+			    int candidate)
+{
+	int		i, isupdate, rc = 0, nretries = 1;
+	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;
+	struct berval	mapped;
+	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.target = mt;
+	dc.conn = op->o_conn;
+	dc.rs = rs;
+	dc.ctx = "modifyDN";
+
+	switch ( asyncmeta_dn_massage( &dc, &op->o_req_dn, &mdn ) )
+	{
+	case LDAP_SUCCESS:
+		break;
+	case LDAP_UNWILLING_TO_PERFORM:
+		rs->sr_err = LDAP_UNWILLING_TO_PERFORM;
+		rs->sr_text = "Operation not allowed";
+		retcode = META_SEARCH_ERR;
+		goto doreturn;
+	default:
+		rs->sr_err = LDAP_NO_SUCH_OBJECT;
+		retcode = META_SEARCH_NOT_CANDIDATE;
+		goto doreturn;
+	}
+
+	for ( i = 0, ml = op->orm_modlist; ml; i++ ,ml = ml->sml_next )
+		;
+
+	mods = ch_malloc( sizeof( LDAPMod )*i );
+	if ( mods == NULL ) {
+		rs->sr_err = LDAP_OTHER;
+		retcode = META_SEARCH_ERR;
+		goto doreturn;
+	}
+	modv = ( LDAPMod ** )ch_malloc( ( i + 1 )*sizeof( LDAPMod * ) );
+	if ( modv == NULL ) {
+		rs->sr_err = LDAP_OTHER;
+		retcode = META_SEARCH_ERR;
+		goto doreturn;
+	}
+
+	dc.ctx = "modifyAttrDN";
+	isupdate = be_shadow_update( op );
+	for ( i = 0, ml = op->orm_modlist; ml; ml = ml->sml_next ) {
+		int	j, is_oc = 0;
+
+		if ( !isupdate && !get_relax( op ) && ml->sml_desc->ad_type->sat_no_user_mod  )
+		{
+			continue;
+		}
+
+		if ( ml->sml_desc == slap_schema.si_ad_objectClass
+				|| ml->sml_desc == slap_schema.si_ad_structuralObjectClass )
+		{
+			is_oc = 1;
+			mapped = ml->sml_desc->ad_cname;
+
+		} else {
+			asyncmeta_map( &mt->mt_rwmap.rwm_at,
+					&ml->sml_desc->ad_cname, &mapped,
+					BACKLDAP_MAP );
+			if ( BER_BVISNULL( &mapped ) || BER_BVISEMPTY( &mapped ) ) {
+				continue;
+			}
+		}
+
+		modv[ i ] = &mods[ i ];
+		mods[ i ].mod_op = ml->sml_op | LDAP_MOD_BVALUES;
+		mods[ i ].mod_type = mapped.bv_val;
+
+		/*
+		 * FIXME: dn-valued attrs should be rewritten
+		 * to allow their use in ACLs at the back-ldap
+		 * level.
+		 */
+		if ( ml->sml_values != NULL ) {
+			if ( is_oc ) {
+				for ( j = 0; !BER_BVISNULL( &ml->sml_values[ j ] ); j++ )
+					;
+				mods[ i ].mod_bvalues =
+					(struct berval **)ch_malloc( ( j + 1 ) *
+					sizeof( struct berval * ) );
+				for ( j = 0; !BER_BVISNULL( &ml->sml_values[ j ] ); ) {
+					struct ldapmapping	*mapping;
+
+					asyncmeta_mapping( &mt->mt_rwmap.rwm_oc,
+							&ml->sml_values[ j ], &mapping, BACKLDAP_MAP );
+
+					if ( mapping == NULL ) {
+						if ( mt->mt_rwmap.rwm_oc.drop_missing ) {
+							continue;
+						}
+						mods[ i ].mod_bvalues[ j ] = &ml->sml_values[ j ];
+
+					} else {
+						mods[ i ].mod_bvalues[ j ] = &mapping->dst;
+					}
+					j++;
+				}
+				mods[ i ].mod_bvalues[ j ] = NULL;
+
+			} else {
+				if ( ml->sml_desc->ad_type->sat_syntax ==
+						slap_schema.si_syn_distinguishedName )
+				{
+					( void )asyncmeta_dnattr_rewrite( &dc, ml->sml_values );
+					if ( ml->sml_values == NULL ) {
+						continue;
+					}
+				}
+
+				for ( j = 0; !BER_BVISNULL( &ml->sml_values[ j ] ); j++ )
+					;
+				mods[ i ].mod_bvalues =
+					(struct berval **)ch_malloc( ( j + 1 ) *
+					sizeof( struct berval * ) );
+				for ( j = 0; !BER_BVISNULL( &ml->sml_values[ j ] ); j++ ) {
+					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;
+
+retry:;
+	ctrls = op->o_ctrls;
+	if ( asyncmeta_controls_add( op, rs, mc, candidate, &ctrls ) != LDAP_SUCCESS )
+	{
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		retcode = META_SEARCH_ERR;
+		goto done;
+	}
+
+	ber = ldap_build_modify_req( msc->msc_ld, mdn.bv_val, modv, ctrls, NULL, &msgid);
+	if (ber) {
+		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;
+
+		switch ( rc ) {
+		case LDAP_SUCCESS:
+			retcode = META_SEARCH_CANDIDATE;
+			asyncmeta_set_msc_time(msc);
+			break;
+
+		case LDAP_SERVER_DOWN:
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+			asyncmeta_clear_one_msc(NULL, mc, candidate);
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			if ( nretries && asyncmeta_retry( op, rs, &mc, candidate, LDAP_BACK_DONTSEND ) ) {
+				nretries = 0;
+				/* if the identity changed, there might be need to re-authz */
+				(void)mi->mi_ldap_extra->controls_free( op, rs, &ctrls );
+				goto retry;
+			}
+
+		default:
+			candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+			retcode = META_SEARCH_ERR;
+		}
+	}
+
+done:
+	(void)mi->mi_ldap_extra->controls_free( op, rs, &ctrls );
+
+	if ( mdn.bv_val != op->o_req_dn.bv_val ) {
+		free( mdn.bv_val );
+		BER_BVZERO( &mdn );
+	}
+	if ( modv != NULL ) {
+		for ( i = 0; modv[ i ]; i++ ) {
+			free( modv[ i ]->mod_bvalues );
+		}
+	}
+	free( mods );
+	free( modv );
+
+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;
+	OperationBuffer opbuf;
+	bm_context_t *bc;
+	SlapReply *candidates;
+	slap_callback *cb = op->o_callback;
+
+	Debug(LDAP_DEBUG_ARGS, "==> asyncmeta_back_modify: %s\n",
+	      op->o_req_dn.bv_val, 0, 0 );
+
+	asyncmeta_new_bm_context(op, rs, &bc, mi->mi_ntargets );
+	if (bc == NULL) {
+		rs->sr_err = LDAP_OTHER;
+		asyncmeta_sender_error(op, rs, cb);
+		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) {
+		asyncmeta_sender_error(op, rs, cb);
+		asyncmeta_clear_bm_context(bc);
+		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;
+
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	rc = asyncmeta_add_message_queue(mc, bc);
+	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";
+		asyncmeta_clear_bm_context(bc);
+		asyncmeta_sender_error(op, rs, cb);
+		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=\"%ld\"\n", op->o_log_prefix, candidate , 0);
+
+		rc = asyncmeta_back_modify_start( op, rs, mc, bc, candidate);
+		if (rc == META_SEARCH_ERR) {
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+			asyncmeta_drop_bc(mc, bc);
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			asyncmeta_sender_error(op, rs, cb);
+			asyncmeta_clear_bm_context(bc);
+			goto finish;
+
+		}
+			break;
+	case META_SEARCH_NOT_CANDIDATE:
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_modify: NOT_CANDIDATE "
+		       "cnd=\"%ld\"\n", op->o_log_prefix, candidate , 0);
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+		asyncmeta_drop_bc(mc, bc);
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+		asyncmeta_sender_error(op, rs, cb);
+		asyncmeta_clear_bm_context(bc);
+		goto finish;
+
+	case META_SEARCH_NEED_BIND:
+	case META_SEARCH_CONNECTING:
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_modify: NEED_BIND "
+		       "cnd=\"%ld\" %p\n", op->o_log_prefix, candidate , &mc->mc_conns[candidate]);
+		rc = asyncmeta_dobind_init(op, rs, bc, mc, candidate);
+		if (rc == META_SEARCH_ERR) {
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+			asyncmeta_drop_bc(mc, bc);
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			asyncmeta_sender_error(op, rs, cb);
+			asyncmeta_clear_bm_context(bc);
+			goto finish;
+		}
+		break;
+	case META_SEARCH_BINDING:
+			Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_modify: BINDING "
+			       "cnd=\"%ld\" %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_modify: ERR "
+			       "cnd=\"%ldd\"\n", op->o_log_prefix, candidate , 0);
+			candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+			candidates[ candidate ].sr_type = REP_RESULT;
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+			asyncmeta_drop_bc(mc, bc);
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			asyncmeta_sender_error(op, rs, cb);
+			asyncmeta_clear_bm_context(bc);
+			goto finish;
+		default:
+			assert( 0 );
+			break;
+		}
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	asyncmeta_start_one_listener(mc, candidates, candidate);
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+finish:
+	return rs->sr_err;
+}

servers/slapd/back-asyncmeta/modrdn.c

@@ -0,0 +1,315 @@
+/* modrdn.c - modrdn request handler for back-syncmeta */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016 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 "../back-ldap/back-ldap.h"
+#include "back-asyncmeta.h"
+#include "../../../libraries/liblber/lber-int.h"
+#include "../../../libraries/libldap/ldap-int.h"
+
+meta_search_candidate_t
+asyncmeta_back_modrdn_start(Operation *op,
+			    SlapReply *rs,
+			    a_metaconn_t *mc,
+			    bm_context_t *bc,
+			    int candidate)
+{
+	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, nretries = 1;
+	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.target = mt;
+	dc.conn = op->o_conn;
+	dc.rs = rs;
+
+	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
+		 */
+		dc.ctx = "newSuperiorDN";
+		if ( asyncmeta_dn_massage( &dc, op->orr_newSup, &mnewSuperior ) ) {
+			rs->sr_err = LDAP_OTHER;
+			retcode = META_SEARCH_ERR;
+			goto done;
+		}
+	}
+
+	/*
+	 * Rewrite the modrdn dn, if required
+	 */
+	dc.ctx = "modrDN";
+	if ( asyncmeta_dn_massage( &dc, &op->o_req_dn, &mdn ) ) {
+		rs->sr_err = LDAP_OTHER;
+		retcode = META_SEARCH_ERR;
+		goto done;
+	}
+
+	/* 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 );
+	}
+retry:;
+	ctrls = op->o_ctrls;
+	if ( asyncmeta_controls_add( op, rs, mc, candidate, &ctrls ) != LDAP_SUCCESS )
+	{
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		retcode = META_SEARCH_ERR;
+		goto done;
+	}
+
+	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) {
+		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;
+
+		switch ( rc ) {
+		case LDAP_SUCCESS:
+			retcode = META_SEARCH_CANDIDATE;
+			asyncmeta_set_msc_time(msc);
+			break;
+
+		case LDAP_SERVER_DOWN:
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+			asyncmeta_clear_one_msc(NULL, mc, candidate);
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			if ( nretries && asyncmeta_retry( op, rs, &mc, candidate, LDAP_BACK_DONTSEND ) ) {
+				nretries = 0;
+				/* if the identity changed, there might be need to re-authz */
+				(void)mi->mi_ldap_extra->controls_free( op, rs, &ctrls );
+				goto retry;
+			}
+
+		default:
+			candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+			retcode = META_SEARCH_ERR;
+		}
+	}
+
+done:
+	(void)mi->mi_ldap_extra->controls_free( op, rs, &ctrls );
+
+	if ( mdn.bv_val != op->o_req_dn.bv_val ) {
+		free( mdn.bv_val );
+		BER_BVZERO( &mdn );
+	}
+
+	if ( !BER_BVISNULL( &mnewSuperior )
+			&& mnewSuperior.bv_val != op->orr_newSup->bv_val )
+	{
+		free( mnewSuperior.bv_val );
+		BER_BVZERO( &mnewSuperior );
+	}
+
+	if ( newrdn.bv_val != op->orr_newrdn.bv_val ) {
+		op->o_tmpfree( newrdn.bv_val, op->o_tmpmemctx );
+	}
+
+doreturn:;
+	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;
+	OperationBuffer opbuf;
+	bm_context_t *bc;
+	SlapReply *candidates;
+	slap_callback *cb = op->o_callback;
+
+	Debug(LDAP_DEBUG_ARGS, "==> asyncmeta_back_modrdn: %s\n",
+	      op->o_req_dn.bv_val, 0, 0 );
+
+	asyncmeta_new_bm_context(op, rs, &bc, mi->mi_ntargets );
+	if (bc == NULL) {
+		rs->sr_err = LDAP_OTHER;
+		asyncmeta_sender_error(op, rs, cb);
+		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) {
+		asyncmeta_sender_error(op, rs, cb);
+		asyncmeta_clear_bm_context(bc);
+		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;
+
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	rc = asyncmeta_add_message_queue(mc, bc);
+	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";
+		asyncmeta_clear_bm_context(bc);
+		asyncmeta_sender_error(op, rs, cb);
+		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=\"%ld\"\n", op->o_log_prefix, candidate , 0);
+
+		rc = asyncmeta_back_modrdn_start( op, rs, mc, bc, candidate);
+		if (rc == META_SEARCH_ERR) {
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+			asyncmeta_drop_bc(mc, bc);
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			asyncmeta_sender_error(op, rs, cb);
+			asyncmeta_clear_bm_context(bc);
+			goto finish;
+
+		}
+			break;
+	case META_SEARCH_NOT_CANDIDATE:
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_modrdn: NOT_CANDIDATE "
+		       "cnd=\"%ld\"\n", op->o_log_prefix, candidate , 0);
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+		asyncmeta_drop_bc(mc, bc);
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+		asyncmeta_sender_error(op, rs, cb);
+		asyncmeta_clear_bm_context(bc);
+		goto finish;
+
+	case META_SEARCH_NEED_BIND:
+	case META_SEARCH_CONNECTING:
+		Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_modrdn: NEED_BIND "
+		       "cnd=\"%ld\" %p\n", op->o_log_prefix, candidate , &mc->mc_conns[candidate]);
+		rc = asyncmeta_dobind_init(op, rs, bc, mc, candidate);
+		if (rc == META_SEARCH_ERR) {
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+			asyncmeta_drop_bc(mc, bc);
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			asyncmeta_sender_error(op, rs, cb);
+			asyncmeta_clear_bm_context(bc);
+			goto finish;
+		}
+		break;
+	case META_SEARCH_BINDING:
+			Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_modrdn: BINDING "
+			       "cnd=\"%ld\" %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=\"%ldd\"\n", op->o_log_prefix, candidate , 0);
+			candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+			candidates[ candidate ].sr_type = REP_RESULT;
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+			asyncmeta_drop_bc(mc, bc);
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			asyncmeta_sender_error(op, rs, cb);
+			asyncmeta_clear_bm_context(bc);
+			goto finish;
+		default:
+			assert( 0 );
+			break;
+		}
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	asyncmeta_start_one_listener(mc, candidates, candidate);
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+finish:
+	return rs->sr_err;
+}

servers/slapd/back-asyncmeta/proto-asyncmeta.h

@@ -0,0 +1,54 @@
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016 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_op_abandon		asyncmeta_back_abandon;
+
+extern BI_connection_destroy	asyncmeta_back_conn_destroy;
+
+int asyncmeta_back_init_cf( BackendInfo *bi );
+
+LDAP_END_DECL
+
+#endif /* PROTO_ASYNCMETA_H */

servers/slapd/back-asyncmeta/search.c

@@ -0,0 +1,680 @@
+/* search.c - search request handler for back-asyncmeta */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016 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 "../../../libraries/libldap/ldap-int.h"
+#undef	ldap_debug
+#define	ldap_debug	slap_debug
+
+static void
+asyncmeta_handle_onerr_stop(Operation *op,
+			    SlapReply *rs,
+			    a_metaconn_t *mc,
+			    bm_context_t *bc,
+			    int candidate,
+			    slap_callback *cb)
+{
+	a_metainfo_t *mi = mc->mc_info;
+	int j;
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	if (bc->bc_active > 0) {
+		ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+		return;
+	}
+	bc->bc_active = 1;
+	asyncmeta_drop_bc(mc, bc);
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+
+	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_abandon_candidate( mc, op,
+						bc->candidates[ j ].sr_msgid, j );
+		}
+	}
+	if (cb != NULL) {
+		op->o_callback = cb;
+	}
+	send_ldap_result(op, rs);
+	asyncmeta_clear_bm_context(bc);
+}
+
+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 )
+{
+	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;
+	int			realscope = op->ors_scope;
+	struct berval		mbase = BER_BVNULL;
+	struct berval		mfilter = BER_BVNULL;
+	char			**mapped_attrs = NULL;
+	int			rc;
+	meta_search_candidate_t	retcode;
+	int timelimit;
+	int			nretries = 1;
+	LDAPControl		**ctrls = NULL;
+	BerElement *ber;
+	ber_int_t	msgid;
+#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[%d]\n", op->o_log_prefix, candidate, 0 );
+	/*
+	 * 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.target = mt;
+	dc.ctx = "searchBase";
+	dc.conn = op->o_conn;
+	dc.rs = rs;
+	switch ( asyncmeta_dn_massage( &dc, &realbase, &mbase ) ) {
+	case LDAP_SUCCESS:
+		break;
+
+	case LDAP_UNWILLING_TO_PERFORM:
+		rs->sr_err = LDAP_UNWILLING_TO_PERFORM;
+		rs->sr_text = "Operation not allowed";
+		retcode = META_SEARCH_ERR;
+		goto doreturn;
+
+	default:
+
+		/*
+		 * this target is no longer candidate
+		 */
+		retcode = META_SEARCH_NOT_CANDIDATE;
+		goto doreturn;
+	}
+
+	/*
+	 * Maps filter
+	 */
+	rc = asyncmeta_filter_map_rewrite( &dc, op->ors_filter,
+			&mfilter, BACKLDAP_MAP, NULL );
+	switch ( rc ) {
+	case LDAP_SUCCESS:
+		break;
+
+	case LDAP_COMPARE_FALSE:
+	default:
+		/*
+		 * this target is no longer candidate
+		 */
+		retcode = META_SEARCH_NOT_CANDIDATE;
+		goto done;
+	}
+
+	/*
+	 * Maps required attributes
+	 */
+	rc = asyncmeta_map_attrs( op, &mt->mt_rwmap.rwm_at,
+			op->ors_attrs, BACKLDAP_MAP, &mapped_attrs );
+	if ( rc != LDAP_SUCCESS ) {
+		/*
+		 * this target is no longer candidate
+		 */
+		retcode = META_SEARCH_NOT_CANDIDATE;
+		goto done;
+	}
+
+	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 */
+
+retry:;
+	asyncmeta_set_msc_time(msc);
+	ctrls = op->o_ctrls;
+	if (nretries == 0)
+	{
+		if (rc != LDAP_SUCCESS)
+		{
+			rs->sr_err = LDAP_BUSY;
+			retcode = META_SEARCH_ERR;
+			candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		        goto done;
+		}
+	}
+
+	if ( asyncmeta_controls_add( op, rs, mc, candidate, &ctrls )
+		!= LDAP_SUCCESS )
+	{
+		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+		retcode = META_SEARCH_NOT_CANDIDATE;
+		goto done;
+	}
+
+	/*
+	 * Starts the search
+	 */
+	ber = ldap_build_search_req( msc->msc_ld,
+			mbase.bv_val, realscope, mfilter.bv_val,
+			mapped_attrs, op->ors_attrsonly,
+			ctrls, NULL, timelimit, op->ors_slimit, op->ors_deref,
+			&msgid );
+	if (ber) {
+		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;
+		switch ( rc ) {
+		case LDAP_SUCCESS:
+			retcode = META_SEARCH_CANDIDATE;
+			asyncmeta_set_msc_time(msc);
+			break;
+
+		case LDAP_SERVER_DOWN:
+			ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+			if (mc->mc_active < 1) {
+				asyncmeta_clear_one_msc(NULL, mc, candidate);
+			}
+			ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+			if ( nretries && asyncmeta_retry( op, rs, &mc, candidate, LDAP_BACK_DONTSEND ) ) {
+				nretries = 0;
+				/* if the identity changed, there might be need to re-authz */
+				(void)mi->mi_ldap_extra->controls_free( op, rs, &ctrls );
+				goto retry;
+			}
+			rs->sr_err = LDAP_UNAVAILABLE;
+			retcode = META_SEARCH_ERR;
+			break;
+		default:
+			candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
+			retcode = META_SEARCH_NOT_CANDIDATE;
+		}
+	}
+
+done:;
+	(void)mi->mi_ldap_extra->controls_free( op, rs, &ctrls );
+#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 ( mapped_attrs ) {
+		ber_memfree_x( mapped_attrs, op->o_tmpmemctx );
+	}
+	if ( mfilter.bv_val != op->ors_filterstr.bv_val ) {
+		ber_memfree_x( mfilter.bv_val, NULL );
+	}
+	if ( mbase.bv_val != realbase.bv_val ) {
+		free( mbase.bv_val );
+	}
+
+doreturn:;
+	Debug( LDAP_DEBUG_TRACE, "%s <<< asyncmeta_back_search_start[%p]=%d\n", op->o_log_prefix, msc, 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;
+	struct timeval	save_tv = { 0, 0 },
+			tv;
+	time_t		stoptime = (time_t)(-1),
+			lastres_time = slap_get_time(),
+			timeout = 0;
+	int		rc = 0, sres = LDAP_SUCCESS;
+	char		*matched = NULL;
+	int		last = 0, ncandidates = 0,
+			initial_candidates = 0, candidate_match = 0,
+			needbind = 0;
+	ldap_back_send_t	sendok = LDAP_BACK_SENDERR;
+	long		i;
+	int		is_ok = 0;
+	void		*savepriv;
+	SlapReply	*candidates = NULL;
+	int		do_taint = 0;
+	bm_context_t *bc;
+	a_metaconn_t *mc;
+	slap_callback *cb = op->o_callback;
+
+	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 );
+	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) {
+		op->o_callback = cb;
+		send_ldap_result(op, rs);
+		asyncmeta_clear_bm_context(bc);
+		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 ];
+		}
+	}
+
+	bc->timeout = timeout;
+	bc->stoptime = op->o_time + bc->timeout;
+
+	if ( op->ors_tlimit != SLAP_NO_LIMIT ) {
+		stoptime = op->o_time + op->ors_tlimit;
+		if (stoptime < bc->stoptime) {
+			bc->stoptime = stoptime;
+			bc->searchtime = 1;
+			bc->timeout = op->ors_tlimit;
+		}
+	}
+
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	rc = asyncmeta_add_message_queue(mc, bc);
+	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";
+		asyncmeta_clear_bm_context(bc);
+		op->o_callback = cb;
+		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;
+		}
+
+		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 , 0);
+
+			rc = asyncmeta_back_search_start( op, rs, mc, bc, i,  NULL, 0 );
+			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,cb);
+					goto finish;
+				}
+				else {
+					continue;
+				}
+			}
+			break;
+		case META_SEARCH_NOT_CANDIDATE:
+			Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_search: NOT_CANDIDATE "
+			       "cnd=\"%ld\"\n", op->o_log_prefix, i , 0);
+			candidates[ i ].sr_msgid = META_MSGID_IGNORE;
+			break;
+
+		case META_SEARCH_NEED_BIND:
+		case META_SEARCH_CONNECTING:
+			Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_search: NEED_BIND "
+			       "cnd=\"%ld\" %p\n", op->o_log_prefix, i , &mc->mc_conns[i]);
+			ncandidates++;
+			rc = asyncmeta_dobind_init(op, rs, bc, mc, i);
+			if (rc == META_SEARCH_ERR) {
+				candidates[ i ].sr_msgid = META_MSGID_IGNORE;
+				if ( META_BACK_ONERR_STOP( mi ) ) {
+					asyncmeta_handle_onerr_stop(op,rs,mc,bc,i,cb);
+					goto finish;
+				}
+				else {
+					continue;
+				}
+			}
+			break;
+		case META_SEARCH_BINDING:
+			Debug( LDAP_DEBUG_TRACE, "%s asyncmeta_back_search: BINDING "
+			       "cnd=\"%ld\" %p\n", op->o_log_prefix, i , &mc->mc_conns[i]);
+			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 , 0);
+			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,cb);
+				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);
+		op->o_callback = cb;
+		send_ldap_result(op, rs);
+		asyncmeta_clear_bm_context(bc);
+		goto finish;
+	}
+	ldap_pvt_thread_mutex_lock( &mc->mc_om_mutex);
+	asyncmeta_start_listeners(mc, candidates);
+	ldap_pvt_thread_mutex_unlock( &mc->mc_om_mutex);
+finish:
+	return rs->sr_err;
+}

servers/slapd/back-asyncmeta/suffixmassage.c

@@ -0,0 +1,112 @@
+/* suffixmassage.c - massages ldap backend dns */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016 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>
+ * Copyright 2000, Pierangelo Masarati, All rights reserved. <ando@sys-net.it>
+ *
+ * Module back-ldap, originally developed by Howard Chu
+ *
+ * has been modified by Pierangelo Masarati. The original copyright
+ * notice has been maintained.
+ *
+ * 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.
+ */
+
+#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"
+
+int
+asyncmeta_dn_massage(
+	a_dncookie	*dc,
+	struct berval	*dn,
+	struct berval	*res )
+{
+	int		rc = 0;
+	static char	*dmy = "";
+
+	switch ( rewrite_session( dc->target->mt_rwmap.rwm_rw, dc->ctx,
+				( dn->bv_val ? dn->bv_val : dmy ),
+				dc->conn, &res->bv_val ) )
+	{
+	case REWRITE_REGEXEC_OK:
+		if ( res->bv_val != NULL ) {
+			res->bv_len = strlen( res->bv_val );
+		} else {
+			*res = *dn;
+		}
+		Debug( LDAP_DEBUG_ARGS,
+			"[rw] %s: \"%s\" -> \"%s\"\n",
+			dc->ctx,
+			BER_BVISNULL( dn ) ? "" : dn->bv_val,
+			BER_BVISNULL( res ) ? "" : res->bv_val );
+		rc = LDAP_SUCCESS;
+		break;
+
+	case REWRITE_REGEXEC_UNWILLING:
+		if ( dc->rs ) {
+			dc->rs->sr_err = LDAP_UNWILLING_TO_PERFORM;
+			dc->rs->sr_text = "Operation not allowed";
+		}
+		rc = LDAP_UNWILLING_TO_PERFORM;
+		break;
+
+	case REWRITE_REGEXEC_ERR:
+		if ( dc->rs ) {
+			dc->rs->sr_err = LDAP_OTHER;
+			dc->rs->sr_text = "Rewrite error";
+		}
+		rc = LDAP_OTHER;
+		break;
+	}
+
+	if ( res->bv_val == dmy ) {
+		BER_BVZERO( res );
+	}
+
+	return rc;
+}

servers/slapd/back-asyncmeta/unbind.c

@@ -0,0 +1,55 @@
+/* unbind.c - unbind handler for back-asyncmeta */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2016 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 "../back-ldap/back-ldap.h"
+#include "back-asyncmeta.h"
+
+int
+asyncmeta_back_conn_destroy(
+	Backend		*be,
+	Connection	*conn )
+{
+	a_metainfo_t	*mi = ( a_metainfo_t * )be->be_private;
+	int		i;
+
+	Debug( LDAP_DEBUG_TRACE,
+		"=>asyncmeta_back_conn_destroy: fetching conn=%ld DN=\"%s\"\n",
+		conn->c_connid,
+		BER_BVISNULL( &conn->c_ndn ) ? "" : conn->c_ndn.bv_val, 0 );
+	/*
+	 * Cleanup rewrite session
+	 */
+	for ( i = 0; i < mi->mi_ntargets; ++i ) {
+		rewrite_session_delete( mi->mi_targets[ i ]->mt_rwmap.rwm_rw, conn );
+	}
+
+	return 0;
+}

servers/slapd/backover.c

@@ -255,6 +255,21 @@ over_back_response ( Operation *op, SlapReply *rs )
 	return rc;
 }
 
+static int
+over_back_response_cleanup(Operation *op, SlapReply *rs)
+{
+    if (rs->sr_type == REP_RESULT) {
+        if (op->o_callback != NULL) {
+            slap_callback *sc = op->o_callback;
+            op->o_callback = sc->sc_next;
+
+            free( sc );
+        }
+    }
+
+    return 0;
+}
+
 static int
 over_access_allowed(
 	Operation		*op,
@@ -727,7 +742,8 @@ over_op_func(
 	slap_overinfo *oi;
 	slap_overinst *on;
 	BackendDB *be = op->o_bd, db;
-	slap_callback cb = {NULL, over_back_response, NULL, NULL}, **sc;
+	slap_callback **sc;
+	slap_callback *cb = (slap_callback *) ch_malloc( sizeof( slap_callback ));
 	int rc = SLAP_CB_CONTINUE;
 
 	/* FIXME: used to happen for instance during abandon
@@ -742,14 +758,18 @@ over_op_func(
 		db.be_flags |= SLAP_DBFLAG_OVERLAY;
 		op->o_bd = &db;
 	}
-	cb.sc_next = op->o_callback;
-	cb.sc_private = oi;
-	op->o_callback = &cb;
+	cb->sc_cleanup = over_back_response_cleanup;
+	cb->sc_response = over_back_response;
+	cb->sc_writewait = NULL;
+	cb->sc_next = op->o_callback;
+	cb->sc_private = oi;
+	op->o_callback = cb;
 
 	rc = overlay_op_walk( op, rs, which, oi, on );
 	for ( sc = &op->o_callback; *sc; sc = &(*sc)->sc_next ) {
-		if ( *sc == &cb ) {
-			*sc = cb.sc_next;
+		if ( *sc == cb ) {
+			*sc = cb->sc_next;
+			ch_free( cb );
 			break;
 		}
 	}

tests/progs/slapd-mtread.c

@@ -185,7 +185,7 @@ main( int argc, char **argv )
 	/* by default, tolerate referrals and no such object */
 	tester_ignore_str2errlist( "REFERRAL,NO_SUCH_OBJECT" );
 
-	while ( (i = getopt( argc, argv, "ACc:D:e:Ff:H:h:i:L:l:M:m:p:r:t:T:w:v" )) != EOF ) {
+	while ( (i = getopt( argc, argv, "ACc:D:e:Ff:H:h:i:L:l:M:m:Np:r:t:T:w:v" )) != EOF ) {
 		switch ( i ) {
 		case 'A':
 			noattrs++;