Copyright 2008 Howard Chu, Symas Corp. 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>.

This directory contains a slapd overlay, nssov, that handles
NSS lookup requests through a local Unix Domain socket. It uses the
same IPC protocol as Arthur de Jong's nss-ldapd, and a complete
copy of the nss-ldapd source is included here.

To use this code, you will need the client-side stub library from
nss-ldapd (which resides in nss-ldapd/nss). You will not need the
nslcd daemon; this overlay replaces that part. You should already
be familiar with the RFC2307 and RFC2307bis schema to use this
overlay. See the nss-ldapd/README for more information on the
schema and which features are supported.

To use the overlay, add:

	include <path to>nis.schema

	moduleload <path to>nssov.so
	...

	database hdb
	...
	overlay nssov

to your slapd configuration file. (The nis.schema file contains
the original RFC2307 schema. Some modifications will be needed to
use RFC2307bis.)

The overlay may be configured with Service Search Descriptors (SSDs)
for each NSS service that will be used. SSDs are configured using

	nssov-svc <service> <url>

where the <service> may be one of
	alias
	ether
	group
	host
	netgroup
	network
	passwd
	protocol
	rpc
	service
	shadow

and the <url> must be of the form
	ldap:///[<basedn>][??[<scope>][?<filter>]]

The <basedn> will default to the first suffix of the current database.
The <scope> defaults to "subtree". The default <filter> depends on which
service is being used.

If the local database is actually a proxy to a foreign LDAP server, some
mapping of schema may be needed. Some simple attribute substitutions may
be performed using

	nssov-map <service> <orig> <new>

See the nss-ldapd/README for the original attribute names used in this code.

The overlay also supports dynamic configuration in cn=config. The layout
of the config entry is

	dn: olcOverlay={0}nssov,ocDatabase={1}hdb,cn=config
	objectClass: olcOverlayConfig
	objectClass: olcNssOvConfig
	olcOverlay: {0}nssov
	olcNssSvc: passwd ldap:///ou=users,dc=example,dc=com??one
	olcNssMap: passwd uid accountName

which enables the passwd service, and uses the accountName attribute to
fetch what is usually retrieved from the uid attribute.