.TH SLAPO-RWM 5 "RELEASEDATE" "OpenLDAP LDVERSION"
-.\" Copyright 1998-2004 The OpenLDAP Foundation, All Rights Reserved.
+.\" Copyright 1998-2008 The OpenLDAP Foundation, All Rights Reserved.
.\" Copying restrictions apply. See the COPYRIGHT file.
.\" Copyright 2004, Pierangelo Masarati, All rights reserved. <ando@sys-net.it>
.\" $OpenLDAP$
.\" and maybe manual pages for librewrite.
.\"
.SH NAME
-slapo-rwm \- rewrite/remap overlay
+slapo-rwm \- rewrite/remap overlay to slapd
.SH SYNOPSIS
ETCDIR/slapd.conf
.SH DESCRIPTION
.BR slapd-ldap (5),
or locally, in conjunction with the relay backend described in
.BR slapd-relay (5).
+.LP
+This overlay is experimental.
.SH MAPPING
An important feature of the
.B rwm
same purpose, etc.
If local or foreign name is `*', the name is preserved.
If local name is omitted, the foreign name is removed.
-Unmapped names are preseved if both local and foreign name are `*',
+Unmapped names are preserved if both local and foreign name are `*',
and removed if local name is omitted and foreign name is `*'.
.LP
The local
.I objectClasses
and
.I attributeTypes
-must be defined in the local schema; the foreign ones do not have to.
+must be defined in the local schema; the foreign ones do not have to,
+but users are encouraged to explicitly define the remote attributeTypes
+and the objectClasses they intend to map. All in all, when remapping
+a remote server via back-ldap (\fBslapd-ldap\fP(5))
+or back-meta (\fBslapd-meta\fP(5))
+their definition can be easily obtained by querying the \fIsubschemaSubentry\fP
+of the remote server; the problem should not exist when remapping a local
+database.
Note, however, that the decision whether to rewrite or not attributeTypes
with
.IR "distinguishedName syntax" ,
requires the knowledge of the attributeType syntax.
See the REWRITING section for details.
+.LP
+Note that when mapping DN-valued attributes from local to remote,
+first the DN is rewritten, and then the attributeType is mapped;
+while mapping from remote to local, first the attributeType is mapped,
+and then the DN is rewritten.
+As such, it is important that the local attributeType is appropriately
+defined as using the distinguishedName syntax.
+Also, note that there are DN-related syntaxes (i.e. compound types with
+a portion that is DN-valued), like nameAndOptionalUID,
+whose values are currently not rewritten.
+.LP
+If the foreign type of an attribute mapping is not defined on the local
+server, it might be desirable to have the attribute values normalized after
+the mapping process. Not normalizing the values can lead to wrong results,
+when the
+.B rwm
+overlay is used together with e.g. the
+.B pcache
+overlay. This normalization can be enabled by means of the
+.B rwm-normalize-mapped-attrs
+directive.
+.TP
+.B rwm-normalize-mapped-attrs {yes|no}
+Set this to "yes", if the
+.B rwm
+overlay should try to normalize the values of attributes that are mapped from
+an attribute type that is unknown to the local server. The default value of
+this setting is "no".
.SH SUFFIX MASSAGING
A basic feature of the
.B rwm
and a real naming context by means of the
.B rwm-suffixmassage
directive.
+This, in conjunction with proxy backends,
+.BR slapd-ldap (5)
+and
+.BR slapd-meta (5),
+or with the relay backend,
+.BR slapd-relay (5),
+allows to create virtual views of databases.
+A distinguishing feature of this overlay is that, when instantiated
+before any database, it can modify the DN of requests
+.I before
+database selection.
+For this reason, rules that rewrite the empty DN ("")
+or the subschemaSubentry DN (usually "cn=subschema"),
+would prevent clients from reading the root DSE or the DSA's schema.
.TP
-.B rwm-suffixmassage "<virtual naming context>" "<real naming context>"
+.B rwm-suffixmassage "[<virtual naming context>]" "<real naming context>"
Shortcut to implement naming context rewriting; the trailing part
of the DN is rewritten from the virtual to the real naming context
in the bindDN, searchDN, searchFilterAttrDN, compareDN, compareAttrDN,
addDN, addAttrDN, modifyDN, modifyAttrDN, modrDN, newSuperiorDN,
deleteDN, exopPasswdDN, and from the real to the virtual naming context
in the searchEntryDN, searchAttrDN and matchedDN rewrite contexts.
-By default no rewriting occurs for the searchFilter rewrite context.
-This directive implies setting the
+By default no rewriting occurs for the searchFilter
+and for the referralAttrDN and referralDN rewrite contexts.
+If no \fI<virtual naming context>\fP is given, the first suffix of the
+database is used; this requires the
+.B rwm-suffixmassage
+directive be defined \fIafter\fP the database
+.B suffix
+directive.
+The
+.B rwm-suffixmassage
+directive automatically sets the
.B rwm-rewriteEngine
to
.BR ON .
.SH REWRITING
A string is rewritten according to a set of rules, called a `rewrite
context'.
-The rules are based on Regular Expressions (POSIX regex) with
+The rules are based on POSIX (''extended'') regular expressions with
substring matching; basic variable substitution and map resolution
of substrings is allowed by specific mechanisms detailed in the following.
The behavior of pattern matching/substitution can be altered by a set
for the slapd server (initially dedicated to the LDAP backend):
.LP
.SH Passes
-An incoming string is matched agains a set of
+An incoming string is matched against a set of
.IR rewriteRules .
Rules are made of a
.IR "regex match pattern" ,
honors case in matching (default is case insensitive)
.TP
.B `R'
-use POSIX Basic Regular Expressions (default is Extended)
+use POSIX ''basic'' regular expressions (default is ''extended'')
.TP
.B `M{n}'
allow no more than
as return code if the rule matches; the flag does not alter the recursive
behavior of the rule, so, to have it performed only once, it must be used
in combination with `:', e.g.
-.B `:U{16}'
-returns the value `16' after exactly one execution of the rule, if the
-pattern matches.
+.B `:U{32}'
+returns the value `32' (indicating noSuchObject) after exactly
+one execution of the rule, if the pattern matches.
As a consequence, its behavior is equivalent to `@', with the return
code set to
.BR n ;
or, in other words, `@' is equivalent to `U{0}'.
-By convention, the freely available codes are above 16 included;
-the others are reserved.
+Positive errors are allowed, indicating the related LDAP error codes
+as specified in \fIdraft-ietf-ldapbis-protocol\fP.
.LP
The ordering of the flags can be significant.
For instance: `IG{2}' means ignore errors and jump two lines ahead
More flags (mainly Action Flags) will be added as needed.
.SH "Pattern Matching"
See
-.BR regex (7).
+.BR regex (7)
+and/or
+.BR re_format (7).
.SH "Substitution Pattern Syntax"
Everything starting with `$' requires substitution;
.LP
-the only obvious exception is `$$', which is left as is;
+the only obvious exception is `$$', which is turned into a single `$';
.LP
the basic substitution is `$<d>', where `<d>' is a digit;
0 means the whole string, while 1-9 is a submatch, as discussed in
-.BR regex (7);
+.BR regex (7)
+and/or
+.BR re_format (7).
.LP
a `$' followed by a `{' invokes an advanced substitution.
The pattern is:
assigns a variable in the rewrite context scope; operator
.B &&
assigns a variable that scopes the entire session, e.g. its value
-can be derefenced later by other rewrite contexts
+can be dereferenced later by other rewrite contexts
.TP
.B *
variable dereferencing; <name> must refer to a variable that is
Substitution escaping has been delegated to the `$' symbol,
which is used instead of `\e' in string substitution patterns
because `\e' is already escaped by slapd's low level parsing routines;
-as a consequence,
-.BR regex (7)
-escaping requires two `\e' symbols, e.g. `\fB.*\e.foo\e.bar\fP' must
+as a consequence, regex escaping requires
+two `\e' symbols, e.g. `\fB.*\e.foo\e.bar\fP' must
be written as `\fB.*\e\e.foo\e\e.bar\fP'.
.\"
.\" The symbol can be altered at will by redefining the related macro in
compareDN compare
compareAttrDN compare AVA
addDN add
-addAttrDN add AVA
+addAttrDN add AVA (DN portion of "ref" excluded)
modifyDN modify
-modifyAttrDN modify AVA
+modifyAttrDN modify AVA (DN portion of "ref" excluded)
+referralAttrDN add/modify DN portion of referrals
+ (default to none)
modrDN modrdn
newSuperiorDN modrdn
deleteDN delete
-exopPasswdDN passwd exop DN if proxy
+exopPasswdDN password modify extended operation DN
.fi
.RE
.LP
attributes of search results)
matchedDN all ops (only if applicable; defaults
to searchEntryDN)
+referralDN all ops (only if applicable; defaults
+ to none)
.fi
.RE
.LP
<Context name> is the name that identifies the context, i.e. the name
used by the application to refer to the set of rules it contains.
It is used also to reference sub contexts in string rewriting.
-A context may aliase another one.
+A context may alias another one.
In this case the alias context contains no rule, and any reference to
it will result in accessing the aliased one.
.TP
to any single rule; an optional per-rule limit can be set.
This limit is overridden by setting specific per-rule limits
with the `M{n}' flag.
-.SH "Configuration Examples"
+
+.SH "MAPS"
+Currently, few maps are builtin but additional map types may be
+registered at runtime.
+
+Supported maps are:
+.TP
+.B LDAP <URI> [bindwhen=<when>] [version=<version>] [binddn=<DN>] [credentials=<cred>]
+The
+.B LDAP
+map expands a value by performing a simple LDAP search.
+Its configuration is based on a mandatory URI, whose
+.B attrs
+portion must contain exactly one attribute
+(use
+.B entryDN
+to fetch the DN of an entry).
+If a multi-valued attribute is used, only the first value is considered.
+
+The parameter
+.B bindwhen
+determines when the connection is established.
+It can take the values
+.BR now ,
+.BR later ,
+and
+.BR everytime ,
+respectively indicating that the connection should be created at startup,
+when required, or any time it is used.
+In the former two cases, the connection is cached, while in the latter
+a fresh new one is used all times. This is the default.
+
+The parameters
+.B binddn
+and
+.B credentials
+represent the DN and the password that is used to perform an authenticated
+simple bind before performing the search operation; if not given,
+an anonymous connection is used.
+
+The parameter
+.B version
+can be 2 or 3 to indicate the protocol version that must be used.
+The default is 3.
+
+.TP
+.B slapd <URI>
+The
+.B slapd
+map expands a value by performing an internal LDAP search.
+Its configuration is based on a mandatory URI, which must begin with
+.B "ldap:///"
+(i.e., it must be an LDAP URI and it must not specify a host).
+As with the
+LDAP map, the
+.B attrs
+portion must contain exactly one attribute, and if
+a multi-valued attribute is used, only the first value is considered.
+
+.SH "REWRITE CONFIGURATION EXAMPLES"
.nf
# set to `off' to disable rewriting
rwm-rewriteEngine on
rwm-rewriteEngine on
# all dataflow from client to server referring to DNs
rwm-rewriteContext default
-rwm-rewriteRule "(.*)<virtualnamingcontext>$" "$1<realnamingcontext>" ":"
+rwm-rewriteRule "(.+,)?<virtualnamingcontext>$" "$1<realnamingcontext>" ":"
# empty filter rule
rwm-rewriteContext searchFilter
# all dataflow from server to client
rwm-rewriteContext searchEntryDN
-rwm-rewriteRule "(.*)<realnamingcontext>$" "$1<virtualnamingcontext>" ":"
+rwm-rewriteRule "(.+,)?<realnamingcontext>$" "$1<virtualnamingcontext>" ":"
rwm-rewriteContext searchAttrDN alias searchEntryDN
rwm-rewriteContext matchedDN alias searchEntryDN
+# misc empty rules
+rwm-rewriteContext referralAttrDN
+rwm-rewriteContext referralDN
# Everything defined here goes into the `default' context.
# This rule changes the naming context of anything sent
# to `dc=home,dc=net' to `dc=OpenLDAP, dc=org'
-rwm-rewriteRule "(.*)dc=home,[ ]?dc=net$"
+rwm-rewriteRule "(.+,)?dc=home,[ ]?dc=net$"
"$1dc=OpenLDAP, dc=org" ":"
# since a pretty/normalized DN does not include spaces
# after rdn separators, e.g. `,', this rule suffices:
-rwm-rewriteRule "(.*)dc=home,dc=net$"
+rwm-rewriteRule "(.+,)?dc=home,dc=net$"
"$1dc=OpenLDAP,dc=org" ":"
# Start a new context (ends input of the previous one).
# This one eats blanks
rwm-rewriteContext eatBlanks
-rwm-rewriteRule "(.*),[ ](.*)" "$1,$2"
+rwm-rewriteRule "(.*), (.*)" "$1,$2"
# Here control goes back to the default rewrite
# context; rules are appended to the existing ones.
# The second rule matches everything else and causes
# the value to be rejected.
rwm-rewriteContext searchEntryDN
-rwm-rewriteRule ".*,ou=People,dc=example,dc=com$" "$0" ":@"
+rwm-rewriteRule ".+,ou=People,dc=example,dc=com$" "$0" ":@"
rwm-rewriteRule ".*" "" "#"
.fi
+.SH "MAPPING EXAMPLES"
+The following directives map the object class `groupOfNames' to
+the object class `groupOfUniqueNames' and the attribute type
+`member' to the attribute type `uniqueMember':
+.LP
+.RS
+.nf
+map objectclass groupOfNames groupOfUniqueNames
+map attribute uniqueMember member
+.fi
+.RE
+.LP
+This presents a limited attribute set from the foreign
+server:
+.LP
+.RS
+.nf
+map attribute cn *
+map attribute sn *
+map attribute manager *
+map attribute description *
+map attribute *
+.fi
+.RE
+.LP
+These lines map cn, sn, manager, and description to themselves, and
+any other attribute gets "removed" from the object before it is sent
+to the client (or sent up to the LDAP server). This is obviously a
+simplistic example, but you get the point.
.SH FILES
.TP
ETCDIR/slapd.conf
.BR slapd\-meta (5),
.BR slapd\-relay (5),
.BR slapd (8),
-.BR regex (7).
+.BR regex (7),
+.BR re_format (7).
.SH AUTHOR
Pierangelo Masarati; based on back-ldap rewrite/remap features
by Howard Chu, Pierangelo Masarati.