SLAPD-SOCK(5)

NAME
slapd-sock - Socket backend/overlay to slapd

SYNOPSIS
/etc/openldap/slapd.conf

DESCRIPTION
The Socket backend to slapd(8) uses an external program to handle queries that listens on a Unix domain socket. This makes it possible to have a pool of processes, which persist between requests. This allows multithreaded operation and a high level of efficiency. The external program must have been started independently; slapd(8) itself will not start it.

This module may also be used as an overlay on top of some other database. Use as an overlay allows external actions to be triggered in response to operations on the main database.

CONFIGURATION
These slapd.conf options apply to the SOCK backend database. That is, they must follow a "database sock" line and come before any subsequent "backend" or "database" lines. Other database options are described in the slapd.conf(5) manual page.

Alternatively, to use this module as an overlay, these directives must follow an "overlay sock" line within an existing database definition.

extensions [ binddn | peername | ssf | connid ]*
    Enables the sending of additional meta-attributes with each request.
    binddn: <bound DN>
    peername: IP=<address>:<port>
    ssf: <SSF value>
    connid: <connection ID>

socketpath <pathname>
    Gives the path to a Unix domain socket to which the commands will be sent and from which replies are received.

    When used as an overlay, these additional directives are defined:

sockops [ bind | unbind | search | compare | modify | modrdn | add | delete | extended ]*
    Specify which request types to send to the external program. The default is empty (no requests are sent).

sockresps [ result | search ]*
    Specify which response types to send to the external program. "result" sends just the results of an operation. "search" sends all entries that the database returned for a search request. The default is empty (no responses are sent).

sockdnpat <regexp>
    Specify DN patterns for which the overlay will act. Only operations on DNs matching the specified regular expression will be processed. The default is empty (all DNs are processed).

PROTOCOL
The protocol uses a newline to terminate the command parameters. The following commands are sent:
    ADD
    msgid: <message id>
    <repeat { "suffix:" <database suffix DN> }>
    <entry in LDIF format>
    <blank line>

    BIND
    msgid: <message id>
    <repeat { "suffix:" <database suffix DN> }>
    dn: <DN>
    method: <method number>
    credlen: <length of <credentials>>
    cred: <credentials>
    <blank line>

    COMPARE
    msgid: <message id>
    <repeat { "suffix:" <database suffix DN> }>
    dn: <DN>
    <attribute>: <value>
    <blank line>

    DELETE
    msgid: <message id>
    <repeat { "suffix:" <database suffix DN> }>
    dn: <DN>
    <blank line>

    EXTENDED
    msgid: <message id>
    <repeat { "suffix:" <database suffix DN> }>
    oid: <OID>
    value: <base64-value>
    <blank line>

    MODIFY
    msgid: <message id>
    <repeat { "suffix:" <database suffix DN> }>
    dn: <DN>
    <repeat {
        <"add"/"delete"/"replace">: <attribute>
        <repeat { <attribute>: <value> }>
        -
    }>
    <blank line>

    MODRDN
    msgid: <message id>
    <repeat { "suffix:" <database suffix DN> }>
    dn: <DN>
    newrdn: <new RDN>
    deleteoldrdn: <0 or 1>
    <if new superior is specified: "newSuperior: <DN>">
    <blank line>

    SEARCH
    msgid: <message id>
    <repeat { "suffix:" <database suffix DN> }>
    base: <base DN>
    scope: <0-2, see ldap.h>
    deref: <0-3, see ldap.h>
    sizelimit: <size limit>
    timelimit: <time limit>
    filter: <filter>
    attrsonly: <0 or 1>
    attrs: <"all" or space-separated attribute list>
    <blank line>

    UNBIND
    msgid: <message id>
    <repeat { "suffix:" <database suffix DN> }>
    <blank line>

The commands - except unbind - should output:
    RESULT
    code: <integer>
    matched: <matched DN>
    info: <text>
where only RESULT is mandatory, and then close the socket. The search RESULT should be preceded by the entries in LDIF format, each entry followed by a blank line. Lines starting with `#' or `DEBUG:' are ignored.

When used as an overlay, the external program should return a CONTINUE response if request processing should continue normally, or a regular RESULT response if the external program wishes to bypass the underlying database.

If sockresps includes result or search, the overlay will also send any response messages to the external program (also see KNOWN LIMITATIONS). These will appear as an extended RESULT message or an ENTRY message respectively, both are defined below and the program is not expected to respond to these.

The extended RESULT message is similar to the one above, but also includes the msgid and any configured extensions:
    RESULT
    msgid: <message id>
    code: <integer>
    matched: <matched DN>
    info: <text>
    <blank line>

Typically both the msgid and the connid will be needed to match a result message to a request. The ENTRY message has the form
    ENTRY
    msgid: <message id>
    <entry in LDIF format>
    <blank line>

KNOWN LIMITATIONS
The sock backend does not process extended operation results from an external program.

If sockresps is configured, sock overlay does not consider sockops nor sockdnpat to decide which responses are passed onto the external program, instead, all responses are currently passed on.

ACCESS CONTROL
The sock backend does not honor all ACL semantics as described in slapd.access(5). In general, access to objects is checked by using a dummy object that contains only the DN, so access rules that rely on the contents of the object are not honored. In detail:

The add operation does not require write (=w) access to the children pseudo-attribute of the parent entry.

The bind operation requires auth (=x) access to the entry pseudo-attribute of the entry whose identity is being assessed; auth (=x) access to the credentials is not checked, but rather delegated to the underlying program.

The compare operation requires compare (=c) access to the entry pseudo-attribute of the object whose value is being asserted; compare (=c) access to the attribute whose value is being asserted is not checked.

The delete operation does not require write (=w) access to the children pseudo-attribute of the parent entry.

The modify operation requires write (=w) access to the entry pseudo-attribute; write (=w) access to the specific attributes that are modified is not checked.

The modrdn operation does not require write (=w) access to the children pseudo-attribute of the parent entry, nor to that of the new parent, if different; write (=w) access to the distinguished values of the naming attributes is not checked.

The search operation does not require search (=s) access to the entry pseudo_attribute of the searchBase; search (=s) access to the attributes and values used in the filter is not checked.

The extended operation does not require any access special rights. The external program has to implement any sort of access control.

EXAMPLE
There is an example script in the slapd/back-sock/ directory in the OpenLDAP source tree.

FILES

/etc/openldap/slapd.conf
    default slapd configuration file

SEE ALSO
slapd.conf(5), slapd-config(5), slapd(8).

AUTHOR
Brian Candler, with enhancements by Howard Chu