1 .TH SLAPD-META 5 "RELEASEDATE" "OpenLDAP LDVERSION"
2 .\" Copyright 1998-2008 The OpenLDAP Foundation, All Rights Reserved.
3 .\" Copying restrictions apply. See the COPYRIGHT file.
4 .\" Copyright 2001, Pierangelo Masarati, All rights reserved. <ando@sys-net.it>
7 .\" Portions of this document should probably be moved to slapd-ldap(5)
8 .\" and maybe manual pages for librewrite.
11 slapd-meta \- metadirectory backend to slapd
19 performs basic LDAP proxying with respect to a set of remote LDAP
20 servers, called "targets".
21 The information contained in these servers can be presented as
22 belonging to a single Directory Information Tree (DIT).
24 A basic knowledge of the functionality of the
26 backend is recommended.
27 This backend has been designed as an enhancement of the ldap backend.
28 The two backends share many features (actually they also share
32 backend is intended to proxy operations directed to a single server, the
34 backend is mainly intended for proxying of multiple servers and possibly
35 naming context masquerading.
36 These features, although useful in many scenarios, may result in
37 excessive overhead for some applications, so its use should be
39 In the examples section, some typical scenarios will be discussed.
42 Note: When looping back to the same instance of \fBslapd\fP(8),
43 each connection requires a new thread; as a consequence, \fBslapd\fP(8)
44 must be compiled with thread support, and the \fBthreads\fP parameter
45 may need some tuning; in those cases, unless the multiple target feature
46 is required, one may consider using \fBslapd-relay\fP(5) instead,
47 which performs the relayed operation internally and thus reuses
51 There are examples in various places in this document, as well as in the
52 slapd/back-meta/data/ directory in the OpenLDAP source tree.
56 options apply to the META backend database.
57 That is, they must follow a "database meta" line and come before any
58 subsequent "backend" or "database" lines.
59 Other database options are described in the
63 Note: In early versions of back-ldap and back-meta it was recommended to always set
76 This was required because operational attributes related to entry creation
77 and modification should not be proxied, as they could be mistakenly written
78 to the target server(s), generating an error.
79 The current implementation automatically sets lastmod to \fBoff\fP,
80 so its use is redundant and should be omitted.
82 .SH SPECIAL CONFIGURATION DIRECTIVES
83 Target configuration starts with the "uri" directive.
84 All the configuration directives that are not specific to targets
85 should be defined first for clarity, including those that are common
91 This directive causes a cached connection to be dropped an recreated
92 after a given ttl, regardless of being idle or not.
95 .B default-target none
96 This directive forces the backend to reject all those operations
97 that must resolve to a single target in case none or multiple
99 They include: add, delete, modify, modrdn; compare is not included, as
100 well as bind since, as they don't alter entries, in case of multiple
101 matches an attempt is made to perform the operation on any candidate
102 target, with the constraint that at most one must succeed.
103 This directive can also be used when processing targets to mark a
104 specific target as default.
107 .B dncache-ttl {DISABLED|forever|<ttl>}
108 This directive sets the time-to-live of the DN cache.
109 This caches the target that holds a given DN to speed up target
110 selection in case multiple targets would result from an uncached
111 search; forever means cache never expires; disabled means no DN
112 caching; otherwise a valid ( > 0 ) ttl is required, in the format
118 .B onerr {CONTINUE|report|stop}
119 This directive allows to select the behavior in case an error is returned
120 by one target during a search.
121 The default, \fBcontinue\fP, consists in continuing the operation,
122 trying to return as much data as possible.
123 If the value is set to \fBstop\fP, the search is terminated as soon
124 as an error is returned by one target, and the error is immediately
125 propagated to the client.
126 If the value is set to \fBreport\fP, the search is continuated to the end
127 but, in case at least one target returned an error code, the first
128 non-success error code is returned.
131 .B protocol\-version {0,2,3}
132 This directive indicates what protocol version must be used to contact
134 If set to 0 (the default), the proxy uses the same protocol version
135 used by the client, otherwise the requested protocol is used.
136 The proxy returns \fIunwillingToPerform\fP if an operation that is
137 incompatible with the requested protocol is attempted.
138 If set before any target specification, it affects all targets, unless
139 overridden by any per-target directive.
142 .B pseudoroot-bind-defer {NO|yes}
143 This directive, when set to
145 causes the authentication to the remote servers with the pseudo-root
146 identity to be deferred until actually needed by subsequent operations.
149 .B quarantine <interval>,<num>[;<interval>,<num>[...]]
150 Turns on quarantine of URIs that returned
151 .IR LDAP_UNAVAILABLE ,
152 so that an attempt to reconnect only occurs at given intervals instead
153 of any time a client requests an operation.
154 The pattern is: retry only after at least
156 seconds elapsed since last attempt, for exactly
158 times; then use the next pattern.
161 for the last pattern is "\fB+\fP", it retries forever; otherwise,
162 no more retries occur.
163 This directive must appear before any target specification;
164 it affects all targets with the same pattern.
167 .B rebind-as-user {NO|yes}
168 If this option is given, the client's bind credentials are remembered
169 for rebinds, when trying to re-establish a broken connection,
170 or when chasing a referral, if
176 .B single\-conn {NO|yes}
177 Discards current cached connection when the client rebinds.
180 .B use-temporary-conn {NO|yes}
183 create a temporary connection whenever competing with other threads
184 for a shared one; otherwise, wait until the shared connection is available.
186 .SH TARGET SPECIFICATION
187 Target specification starts with a "uri" directive:
190 .B uri <protocol>://[<host>]/<naming context> [...]
191 The <protocol> part can be anything
192 .BR ldap_initialize (3)
193 accepts ({ldap|ldaps|ldapi} and variants); the <host> may be
194 omitted, defaulting to whatever is set in
196 The <naming context> part is \fImandatory\fP for the first URI,
197 but it \fImust be omitted\fP for subsequent ones, if any.
198 The naming context part must be within the naming context defined for the backend,
203 suffix "\fBdc=foo,dc=com\fP"
204 uri "ldap://x.foo.com/dc=x,\fBdc=foo,dc=com\fP"
209 The <naming context> part doesn't need to be unique across the targets;
210 it may also match one of the values of the "suffix" directive.
211 Multiple URIs may be defined in a single URI statement.
212 The additional URIs must be separate arguments and must not have any
213 <naming context> part. This causes the underlying library
214 to contact the first server of the list that responds.
215 For example, if \fIl1.foo.com\fP and \fIl2.foo.com\fP are shadows
216 of the same server, the directive
219 suffix "\fBdc=foo,dc=com\fP"
220 uri "ldap://l1.foo.com/\fBdc=foo,dc=com\fP" "ldap://l2.foo.com/"
225 causes \fIl2.foo.com\fP to be contacted whenever \fIl1.foo.com\fP
227 In that case, the URI list is internally rearranged, by moving unavailable
228 URIs to the end, so that further connection attempts occur with respect to
229 the last URI that succeeded.
233 .B acl-authcDN "<administrative DN for access control purposes>"
234 DN which is used to query the target server for acl checking,
235 as in the LDAP backend; it is supposed to have read access
236 on the target server to attributes used on the proxy for acl checking.
237 There is no risk of giving away such values; they are only used to
239 .B The acl-authcDN identity is by no means implicitly used by the proxy
240 .B when the client connects anonymously.
243 .B acl-passwd <password>
244 Password used with the
250 .B bind-timeout <microseconds>
251 This directive defines the timeout, in microseconds, used when polling
252 for response after an asynchronous bind connection. The initial call
253 to ldap_result(3) is performed with a trade-off timeout of 100000 us;
254 if that results in a timeout exceeded, subsequent calls use the value
257 The default value is used also for subsequent calls if
260 If set before any target specification, it affects all targets, unless
261 overridden by any per-target directive.
264 .B chase-referrals {YES|no}
265 enable/disable automatic referral chasing, which is delegated to the
266 underlying libldap, with rebinding eventually performed if the
267 \fBrebind-as-user\fP directive is used. The default is to chase referrals.
268 If set before any target specification, it affects all targets, unless
269 overridden by any per-target directive.
272 .B default-target [<target>]
273 The "default-target" directive can also be used during target specification.
274 With no arguments it marks the current target as the default.
275 The optional number marks target <target> as the default one, starting
277 Target <target> must be defined.
280 .B idle-timeout <time>
281 This directive causes a cached connection to be dropped an recreated
282 after it has been idle for the specified time.
283 The value can be specified as
285 [<d>d][<h>h][<m>m][<s>[s]]
287 where <d>, <h>, <m> and <s> are respectively treated as days, hours,
289 If set before any target specification, it affects all targets, unless
290 overridden by any per-target directive.
293 .B map "{attribute|objectclass} [<local name>|*] {<foreign name>|*}"
294 This maps object classes and attributes as in the LDAP backend.
299 .B network-timeout <time>
300 Sets the network timeout value after which
301 .BR poll (2)/ select (2)
304 returns in case of no activity.
305 The value is in seconds, and it can be specified as for
307 If set before any target specification, it affects all targets, unless
308 overridden by any per-target directive.
311 .B nretries {forever|never|<nretries>}
312 This directive defines how many times a bind should be retried
313 in case of temporary failure in contacting a target. If defined
314 before any target specification, it applies to all targets (by default,
317 the global value can be overridden by redefinitions inside each target
321 .B pseudorootdn "<substitute DN in case of rootdn bind>"
322 This directive, if present, sets the DN that will be substituted to
323 the bind DN if a bind with the backend's "rootdn" succeeds.
324 The true "rootdn" of the target server ought not be used; an arbitrary
325 administrative DN should used instead.
328 .B pseudorootpw "<substitute password in case of rootdn bind>"
329 This directive sets the credential that will be used in case a bind
330 with the backend's "rootdn" succeeds, and the bind is propagated to
331 the target using the "pseudorootdn" DN.
333 Note: cleartext credentials must be supplied here; as a consequence,
334 using the pseudorootdn/pseudorootpw directives is inherently unsafe.
338 The rewrite options are described in the "REWRITING" section.
341 .B subtree-exclude "<DN>"
342 This directive instructs back-meta to ignore the current target
343 for operations whose requestDN is subordinate to
345 There may be multiple occurrences of the
347 directive for each of the targets.
350 .B suffixmassage "<virtual naming context>" "<real naming context>"
351 All the directives starting with "rewrite" refer to the rewrite engine
352 that has been added to slapd.
353 The "suffixmassage" directive was introduced in the LDAP backend to
354 allow suffix massaging while proxying.
355 It has been obsoleted by the rewriting tools.
356 However, both for backward compatibility and for ease of configuration
357 when simple suffix massage is required, it has been preserved.
358 It wraps the basic rewriting instructions that perform suffix
359 massaging. See the "REWRITING" section for a detailed list
360 of the rewrite rules it implies.
363 .B t-f-support {NO|yes|discover}
364 enable if the remote server supports absolute filters
365 (see \fIdraft-zeilenga-ldap-t-f\fP for details).
368 support is detected by reading the remote server's root DSE.
369 If set before any target specification, it affects all targets, unless
370 overridden by any per-target directive.
373 .B timeout [<op>=]<val> [...]
374 This directive allows to set per-operation timeouts.
377 \fB<op> ::= bind, add, delete, modrdn, modify, compare, search\fP
379 The overall duration of the \fBsearch\fP operation is controlled either
380 by the \fBtimelimit\fP parameter or by server-side enforced
381 time limits (see \fBtimelimit\fP and \fBlimits\fP in
384 This \fBtimeout\fP parameter controls how long the target can be
385 irresponsive before the operation is aborted.
386 Timeout is meaningless for the remaining operations,
387 \fBunbind\fP and \fBabandon\fP, which do not imply any response,
388 while it is not yet implemented in currently supported \fBextended\fP
390 If no operation is specified, the timeout \fBval\fP affects all
391 supported operations.
392 If specified before any target definition, it affects all targets
393 unless overridden by per-target directives.
395 Note: if the timeout is exceeded, the operation is cancelled
396 (according to the \fBcancel\fP directive);
397 the protocol does not provide any means to rollback operations,
398 so the client will not be notified about the result of the operation,
399 which may eventually succeeded or not.
400 In case the timeout is exceeded during a bind operation, the connection
401 is destroyed, according to RFC4511.
404 .B tls {[try-]start|[try-]propagate}
405 execute the StartTLS extended operation when the connection is initialized;
406 only works if the URI directive protocol scheme is not \fBldaps://\fP.
407 \fBpropagate\fP issues the StartTLS operation only if the original
409 The \fBtry-\fP prefix instructs the proxy to continue operations
410 if the StartTLS operation failed; its use is highly deprecated.
411 If set before any target specification, it affects all targets, unless
412 overridden by any per-target directive.
415 A powerful (and in some sense dangerous) rewrite engine has been added
416 to both the LDAP and Meta backends.
417 While the former can gain limited beneficial effects from rewriting
418 stuff, the latter can become an amazingly powerful tool.
420 Consider a couple of scenarios first.
422 1) Two directory servers share two levels of naming context;
423 say "dc=a,dc=foo,dc=com" and "dc=b,dc=foo,dc=com".
424 Then, an unambiguous Meta database can be configured as:
429 suffix "\fBdc=foo,dc=com\fP"
430 uri "ldap://a.foo.com/dc=a,\fBdc=foo,dc=com\fP"
431 uri "ldap://b.foo.com/dc=b,\fBdc=foo,dc=com\fP"
435 Operations directed to a specific target can be easily resolved
436 because there are no ambiguities.
437 The only operation that may resolve to multiple targets is a search
438 with base "dc=foo,dc=com" and scope at least "one", which results in
439 spawning two searches to the targets.
441 2a) Two directory servers don't share any portion of naming context,
442 but they'd present as a single DIT
443 [Caveat: uniqueness of (massaged) entries among the two servers is
444 assumed; integrity checks risk to incur in excessive overhead and have
445 not been implemented].
446 Say we have "dc=bar,dc=org" and "o=Foo,c=US",
447 and we'd like them to appear as branches of "dc=foo,dc=com", say
448 "dc=a,dc=foo,dc=com" and "dc=b,dc=foo,dc=com".
449 Then we need to configure our Meta backend as:
454 suffix "dc=foo,dc=com"
456 uri "ldap://a.bar.com/\fBdc=a,dc=foo,dc=com\fP"
457 suffixmassage "\fBdc=a,dc=foo,dc=com\fP" "dc=bar,dc=org"
459 uri "ldap://b.foo.com/\fBdc=b,dc=foo,dc=com\fP"
460 suffixmassage "\fBdc=b,dc=foo,dc=com\fP" "o=Foo,c=US"
464 Again, operations can be resolved without ambiguity, although
465 some rewriting is required.
466 Notice that the virtual naming context of each target is a branch of
467 the database's naming context; it is rewritten back and forth when
468 operations are performed towards the target servers.
469 What "back and forth" means will be clarified later.
471 When a search with base "dc=foo,dc=com" is attempted, if the
472 scope is "base" it fails with "no such object"; in fact, the
473 common root of the two targets (prior to massaging) does not
475 If the scope is "one", both targets are contacted with the base
476 replaced by each target's base; the scope is derated to "base".
477 In general, a scope "one" search is honored, and the scope is derated,
478 only when the incoming base is at most one level lower of a target's
479 naming context (prior to massaging).
481 Finally, if the scope is "sub" the incoming base is replaced
482 by each target's unmassaged naming context, and the scope
485 2b) Consider the above reported scenario with the two servers
486 sharing the same naming context:
491 suffix "\fBdc=foo,dc=com\fP"
493 uri "ldap://a.bar.com/\fBdc=foo,dc=com\fP"
494 suffixmassage "\fBdc=foo,dc=com\fP" "dc=bar,dc=org"
496 uri "ldap://b.foo.com/\fBdc=foo,dc=com\fP"
497 suffixmassage "\fBdc=foo,dc=com\fP" "o=Foo,c=US"
501 All the previous considerations hold, except that now there is
502 no way to unambiguously resolve a DN.
503 In this case, all the operations that require an unambiguous target
504 selection will fail unless the DN is already cached or a default
506 Practical configurations may result as a combination of all the
509 Note on ACLs: at present you may add whatever ACL rule you desire
510 to to the Meta (and LDAP) backends.
511 However, the meaning of an ACL on a proxy may require some
513 Two philosophies may be considered:
515 a) the remote server dictates the permissions; the proxy simply passes
516 back what it gets from the remote server.
518 b) the remote server unveils "everything"; the proxy is responsible
519 for protecting data from unauthorized access.
521 Of course the latter sounds unreasonable, but it is not.
522 It is possible to imagine scenarios in which a remote host discloses
523 data that can be considered "public" inside an intranet, and a proxy
524 that connects it to the internet may impose additional constraints.
525 To this purpose, the proxy should be able to comply with all the ACL
526 matching criteria that the server supports.
527 This has been achieved with regard to all the criteria supported by
528 slapd except a special subtle case (please drop me a note if you can
529 find other exceptions: <ando@openldap.org>).
534 access to dn="<dn>" attrs=<attr>
535 by dnattr=<dnattr> read
540 cannot be matched iff the attribute that is being requested, <attr>,
541 is NOT <dnattr>, and the attribute that determines membership,
542 <dnattr>, has not been requested (e.g. in a search)
544 In fact this ACL is resolved by slapd using the portion of entry it
545 retrieved from the remote server without requiring any further
546 intervention of the backend, so, if the <dnattr> attribute has not
547 been fetched, the match cannot be assessed because the attribute is
548 not present, not because no value matches the requirement!
550 Note on ACLs and attribute mapping: ACLs are applied to the mapped
551 attributes; for instance, if the attribute locally known as "foo" is
552 mapped to "bar" on a remote server, then local ACLs apply to attribute
553 "foo" and are totally unaware of its remote name.
554 The remote server will check permissions for "bar", and the local
555 server will possibly enforce additional restrictions to "foo".
557 .\" If this section is moved, also update the reference in
558 .\" libraries/librewrite/RATIONALE.
561 A string is rewritten according to a set of rules, called a `rewrite
563 The rules are based on POSIX (''extended'') regular expressions (regex)
564 with substring matching; basic variable substitution and map resolution
565 of substrings is allowed by specific mechanisms detailed in the following.
566 The behavior of pattern matching/substitution can be altered by a set
569 The underlying concept is to build a lightweight rewrite module
570 for the slapd server (initially dedicated to the LDAP backend).
572 An incoming string is matched against a set of rules.
573 Rules are made of a regex match pattern, a substitution pattern
574 and a set of actions, described by a set of flags.
575 In case of match a string rewriting is performed according to the
576 substitution pattern that allows to refer to substrings matched in the
578 The actions, if any, are finally performed.
579 The substitution pattern allows map resolution of substrings.
580 A map is a generic object that maps a substitution pattern to a value.
581 The flags are divided in "Pattern matching Flags" and "Action Flags";
582 the former alter the regex match pattern behavior while the latter
583 alter the action that is taken after substitution.
584 .SH "Pattern Matching Flags"
587 honors case in matching (default is case insensitive)
590 use POSIX ''basic'' regular expressions (default is ''extended'')
595 recursive passes for a specific rule; does not alter the max total count
596 of passes, so it can only enforce a stricter limit for a specific rule.
600 apply the rule once only (default is recursive)
603 stop applying rules in case of match; the current rule is still applied
604 recursively; combine with `:' to apply the current rule only once
608 stop current operation if the rule matches, and issue an `unwilling to
614 rules back and forth (watch for loops!).
615 Note that `G{1}' is implicit in every rule.
618 ignores errors in rule; this means, in case of error, e.g. issued by a
619 map, the error is treated as a missed match.
620 The `unwilling to perform' is not overridden.
626 as return code if the rule matches; the flag does not alter the recursive
627 behavior of the rule, so, to have it performed only once, it must be used
628 in combination with `:', e.g.
630 returns the value `16' after exactly one execution of the rule, if the
632 As a consequence, its behavior is equivalent to `@', with the return
635 or, in other words, `@' is equivalent to `U{0}'.
636 By convention, the freely available codes are above 16 included;
637 the others are reserved.
639 The ordering of the flags can be significant.
640 For instance: `IG{2}' means ignore errors and jump two lines ahead
641 both in case of match and in case of error, while `G{2}I' means ignore
642 errors, but jump two lines ahead only in case of match.
644 More flags (mainly Action Flags) will be added as needed.
645 .SH "Pattern matching:"
650 .SH "Substitution Pattern Syntax:"
651 Everything starting with `%' requires substitution;
653 the only obvious exception is `%%', which is left as is;
655 the basic substitution is `%d', where `d' is a digit;
656 0 means the whole string, while 1-9 is a submatch;
658 a `%' followed by a `{' invokes an advanced substitution.
662 `%' `{' [ <op> ] <name> `(' <substitution> `)' `}'
665 where <name> must be a legal name for the map, i.e.
669 <name> ::= [a-z][a-z0-9]* (case insensitive)
670 <op> ::= `>' `|' `&' `&&' `*' `**' `$'
674 and <substitution> must be a legal substitution
675 pattern, with no limits on the nesting level.
680 sub context invocation; <name> must be a legal, already defined
684 external command invocation; <name> must refer to a legal, already
685 defined command name (NOT IMPL.)
688 variable assignment; <name> defines a variable in the running
689 operation structure which can be dereferenced later; operator
691 assigns a variable in the rewrite context scope; operator
693 assigns a variable that scopes the entire session, e.g. its value
694 can be dereferenced later by other rewrite contexts
697 variable dereferencing; <name> must refer to a variable that is
698 defined and assigned for the running operation; operator
700 dereferences a variable scoping the rewrite context; operator
702 dereferences a variable scoping the whole session, e.g. the value
703 is passed across rewrite contexts
706 parameter dereferencing; <name> must refer to an existing parameter;
707 the idea is to make some run-time parameters set by the system
708 available to the rewrite engine, as the client host name, the bind DN
709 if any, constant parameters initialized at config time, and so on;
710 no parameter is currently set by either
714 but constant parameters can be defined in the configuration file
719 Substitution escaping has been delegated to the `%' symbol,
720 which is used instead of `\e' in string substitution patterns
721 because `\e' is already escaped by slapd's low level parsing routines;
722 as a consequence, regex escaping requires two `\e' symbols,
723 e.g. `\fB.*\e.foo\e.bar\fP' must be written as `\fB.*\e\e.foo\e\e.bar\fP'.
725 .\" The symbol can be altered at will by redefining the related macro in
728 .SH "Rewrite context:"
729 A rewrite context is a set of rules which are applied in sequence.
730 The basic idea is to have an application initialize a rewrite
731 engine (think of Apache's mod_rewrite ...) with a set of rewrite
732 contexts; when string rewriting is required, one invokes the
733 appropriate rewrite context with the input string and obtains the
734 newly rewritten one if no errors occur.
736 Each basic server operation is associated to a rewrite context;
737 they are divided in two main groups: client \-> server and
738 server \-> client rewriting.
744 (default) if defined and no specific context
749 searchFilterAttrDN search
751 compareAttrDN compare AVA
755 modifyAttrDN modify AVA
759 exopPasswdDN password modify extended operation DN if proxy
767 searchResult search (only if defined; no default;
768 acts on DN and DN-syntax attributes
770 searchAttrDN search AVA
771 matchedDN all ops (only if applicable)
775 .SH "Basic configuration syntax"
777 .B rewriteEngine { on | off }
778 If `on', the requested rewriting is performed; if `off', no
779 rewriting takes place (an easy way to stop rewriting without
780 altering too much the configuration file).
782 .B rewriteContext <context name> "[ alias <aliased context name> ]"
783 <Context name> is the name that identifies the context, i.e. the name
784 used by the application to refer to the set of rules it contains.
785 It is used also to reference sub contexts in string rewriting.
786 A context may alias another one.
787 In this case the alias context contains no rule, and any reference to
788 it will result in accessing the aliased one.
790 .B rewriteRule "<regex match pattern>" "<substitution pattern>" "[ <flags> ]"
791 Determines how a string can be rewritten if a pattern is matched.
792 Examples are reported below.
793 .SH "Additional configuration syntax:"
795 .B rewriteMap "<map type>" "<map name>" "[ <map attrs> ]"
796 Allows to define a map that transforms substring rewriting into
798 The map is referenced inside the substitution pattern of a rule.
800 .B rewriteParam <param name> <param value>
801 Sets a value with global scope, that can be dereferenced by the
802 command `%{$paramName}'.
804 .B rewriteMaxPasses <number of passes> [<number of passes per rule>]
805 Sets the maximum number of total rewriting passes that can be
806 performed in a single rewrite operation (to avoid loops).
807 A safe default is set to 100; note that reaching this limit is still
808 treated as a success; recursive invocation of rules is simply
810 The count applies to the rewriting operation as a whole, not
811 to any single rule; an optional per-rule limit can be set.
812 This limit is overridden by setting specific per-rule limits
813 with the `M{n}' flag.
814 .SH "Configuration examples:"
816 # set to `off' to disable rewriting
819 # the rules the "suffixmassage" directive implies
821 # all dataflow from client to server referring to DNs
822 rewriteContext default
823 rewriteRule "(.*)<virtualnamingcontext>$" "%1<realnamingcontext>" ":"
825 rewriteContext searchFilter
826 # all dataflow from server to client
827 rewriteContext searchResult
828 rewriteRule "(.*)<realnamingcontext>$" "%1<virtualnamingcontext>" ":"
829 rewriteContext searchAttrDN alias searchResult
830 rewriteContext matchedDN alias searchResult
832 # Everything defined here goes into the `default' context.
833 # This rule changes the naming context of anything sent
834 # to `dc=home,dc=net' to `dc=OpenLDAP, dc=org'
836 rewriteRule "(.*)dc=home,[ ]?dc=net"
837 "%1dc=OpenLDAP, dc=org" ":"
839 # since a pretty/normalized DN does not include spaces
840 # after rdn separators, e.g. `,', this rule suffices:
842 rewriteRule "(.*)dc=home,dc=net"
843 "%1dc=OpenLDAP,dc=org" ":"
845 # Start a new context (ends input of the previous one).
846 # This rule adds blanks between DN parts if not present.
847 rewriteContext addBlanks
848 rewriteRule "(.*),([^ ].*)" "%1, %2"
850 # This one eats blanks
851 rewriteContext eatBlanks
852 rewriteRule "(.*),[ ](.*)" "%1,%2"
854 # Here control goes back to the default rewrite
855 # context; rules are appended to the existing ones.
856 # anything that gets here is piped into rule `addBlanks'
857 rewriteContext default
858 rewriteRule ".*" "%{>addBlanks(%0)}" ":"
860 .\" # Anything with `uid=username' is looked up in
861 .\" # /etc/passwd for gecos (I know it's nearly useless,
862 .\" # but it is there just as a guideline to implementing
864 .\" # Note the `I' flag that leaves `uid=username' in place
865 .\" # if `username' does not have a valid account, and the
866 .\" # `:' that forces the rule to be processed exactly once.
867 .\" rewriteContext uid2Gecos
868 .\" rewriteRule "(.*)uid=([a-z0-9]+),(.+)"
869 .\" "%1cn=%2{xpasswd},%3" "I:"
871 .\" # Finally, in a bind, if one uses a `uid=username' DN,
872 .\" # it is rewritten in `cn=name surname' if possible.
873 .\" rewriteContext bindDN
874 .\" rewriteRule ".*" "%{>addBlanks(%{>uid2Gecos(%0)})}" ":"
876 # Rewrite the search base according to `default' rules.
877 rewriteContext searchBase alias default
879 # Search results with OpenLDAP DN are rewritten back with
880 # `dc=home,dc=net' naming context, with spaces eaten.
881 rewriteContext searchResult
882 rewriteRule "(.*[^ ]?)[ ]?dc=OpenLDAP,[ ]?dc=org"
883 "%{>eatBlanks(%1)}dc=home,dc=net" ":"
885 # Bind with email instead of full DN: we first need
886 # an ldap map that turns attributes into a DN (the
887 # argument used when invoking the map is appended to
888 # the URI and acts as the filter portion)
889 rewriteMap ldap attr2dn "ldap://host/dc=my,dc=org?dn?sub"
891 # Then we need to detect DN made up of a single email,
892 # e.g. `mail=someone@example.com'; note that the rule
893 # in case of match stops rewriting; in case of error,
894 # it is ignored. In case we are mapping virtual
895 # to real naming contexts, we also need to rewrite
896 # regular DNs, because the definition of a bindDn
897 # rewrite context overrides the default definition.
898 rewriteContext bindDN
899 rewriteRule "^mail=[^,]+@[^,]+$" "%{attr2dn(%0)}" ":@I"
901 # This is a rather sophisticated example. It massages a
902 # search filter in case who performs the search has
903 # administrative privileges. First we need to keep
904 # track of the bind DN of the incoming request, which is
905 # stored in a variable called `binddn' with session scope,
906 # and left in place to allow regular binding:
907 rewriteContext bindDN
908 rewriteRule ".+" "%{&&binddn(%0)}%0" ":"
910 # A search filter containing `uid=' is rewritten only
911 # if an appropriate DN is bound.
912 # To do this, in the first rule the bound DN is
913 # dereferenced, while the filter is decomposed in a
914 # prefix, in the value of the `uid=<arg>' AVA, and
915 # in a suffix. A tag `<>' is appended to the DN.
916 # If the DN refers to an entry in the `ou=admin' subtree,
917 # the filter is rewritten OR-ing the `uid=<arg>' with
918 # `cn=<arg>'; otherwise it is left as is. This could be
919 # useful, for instance, to allow apache's auth_ldap-1.4
920 # module to authenticate users with both `uid' and
921 # `cn', but only if the request comes from a possible
922 # `cn=Web auth,ou=admin,dc=home,dc=net' user.
923 rewriteContext searchFilter
924 rewriteRule "(.*\e\e()uid=([a-z0-9_]+)(\e\e).*)"
925 "%{**binddn}<>%{&prefix(%1)}%{&arg(%2)}%{&suffix(%3)}"
927 rewriteRule "[^,]+,ou=admin,dc=home,dc=net"
928 "%{*prefix}|(uid=%{*arg})(cn=%{*arg})%{*suffix}" ":@I"
929 rewriteRule ".*<>" "%{*prefix}uid=%{*arg}%{*suffix}" ":"
931 # This example shows how to strip unwanted DN-valued
932 # attribute values from a search result; the first rule
933 # matches DN values below "ou=People,dc=example,dc=com";
934 # in case of match the rewriting exits successfully.
935 # The second rule matches everything else and causes
936 # the value to be rejected.
937 rewriteContext searchResult
938 rewriteRule ".*,ou=People,dc=example,dc=com" "%0" ":@"
939 rewriteRule ".*" "" "#"
941 .SH "LDAP Proxy resolution (a possible evolution of slapd\-ldap(5)):"
942 In case the rewritten DN is an LDAP URI, the operation is initiated
943 towards the host[:port] indicated in the uri, if it does not refer
948 rewriteRule '^cn=root,.*' '%0' 'G{3}'
949 rewriteRule '^cn=[a-l].*' 'ldap://ldap1.my.org/%0' ':@'
950 rewriteRule '^cn=[m-z].*' 'ldap://ldap2.my.org/%0' ':@'
951 rewriteRule '.*' 'ldap://ldap3.my.org/%0' ':@'
954 (Rule 1 is simply there to illustrate the `G{n}' action; it could have
958 rewriteRule '^cn=root,.*' 'ldap://ldap3.my.org/%0' ':@'
961 with the advantage of saving one rewrite pass ...)
966 backend does not honor all ACL semantics as described in
967 .BR slapd.access (5).
968 In general, access checking is delegated to the remote server(s).
973 pseudo-attribute and to the other attribute values of the entries
976 operation is honored, which is performed by the frontend.
978 .SH PROXY CACHE OVERLAY
979 The proxy cache overlay
980 allows caching of LDAP search requests (queries) in a local database.
987 default slapd configuration file
991 .BR slapo\-pcache (5),
996 Pierangelo Masarati, based on back-ldap by Howard Chu
projects / openldap / blob