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Versions: 00                                                            
Network Working Group                                    Wengyik Yeong
INTERNET-DRAFT                       Performance Systems International
                                                             Tim Howes
                                                University of Michigan
                                                           Steve Kille
                                                      ISODE Consortium


                 Lightweight Directory Access Protocol
               <draft-ietf-asid-ldapv2-protocol-00.txt>


1.  Status of this Memo

This draft document will be submitted to the RFC Editor as a standards
document. Distribution of this memo is unlimited. Please send comments
to the authors, or the discussion group <osi-ds@cs.ucl.ac.uk>.

This document is an Internet-Draft.  Internet-Drafts are working docu-
ments of the Internet Engineering Task Force (IETF), its areas, and its
working groups.  Note that other groups may also distribute working
documents as Internet-Drafts.

Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time.  It is inappropriate to use Internet- Drafts as reference material
or to cite them other than as ``work in progress.''

To learn the current status of any Internet-Draft, please check the
``1id-abstracts.txt'' listing contained in the Internet- Drafts Shadow
Directories on ds.internic.net (US East Coast), nic.nordu.net (Europe),
ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific Rim).

2.  Abstract

The protocol described in this document is designed to provide access to
the X.500 Directory while not incurring the resource requirements of the
Directory Access Protocol (DAP). This protocol is specifically targeted
at simple management applications and browser applications that provide
simple read/write interactive access to the X.500 Directory, and is
intended to be a complement to the DAP itself.

Key aspects of LDAP are

-    Protocol elements are carried directly over TCP or other transport,
     bypassing much of the session/presentation overhead.

-    Many protocol data elements are encoding as ordinary strings (e.g.,



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     Distinguished Names).

-    A lightweight BER encoding is used to encode all protocol elements.

3.  History

The tremendous interest in X.500 [1,2] technology in the Internet has
lead to efforts to reduce the high ``cost of entry'' associated with use
of the technology, such as the Directory Assistance Service [3] and
DIXIE [4]. While efforts such as these have met with success, they have
been solutions based on particular implementations and as such have lim-
ited applicability.  This document continues the efforts to define
Directory protocol alternatives but departs from previous efforts in
that it consciously avoids dependence on particular implementations.

4.  Protocol Model

The general model adopted by this protocol is one of clients performing
protocol operations against servers. In this model, this is accomplished
by a client transmitting a protocol request describing the operation to
be performed to a server, which is then responsible for performing the
necessary operations on the Directory.  Upon completion of the necessary
operations, the server returns a response containing any results or
errors to the requesting client.  In keeping with the goal of easing the
costs associated with use of the Directory, it is an objective of this
protocol to minimize the complexity of clients so as to facilitate
widespread deployment of applications capable of utilizing the Direc-
tory.

Note that, although servers are required to return responses whenever
such responses are defined in the protocol, there is no requirement for
synchronous behavior on the part of either client or server implementa-
tions: requests and responses for multiple operations may be exchanged
by client and servers in any order, as long as clients eventually
receive a response for every request that requires one.

Consistent with the model of servers performing protocol operations on
behalf of clients, it is also to be noted that protocol servers are
expected to handle referrals without resorting to the return of such
referrals to the client. This protocol makes no provisions for the
return of referrals to clients, as the model is one of servers ensuring
the performance of all necessary operations in the Directory, with only
final results or errors being returned by servers to clients.

Note that this protocol can be mapped to a strict subset of the direc-
tory abstract service, so it can be cleanly provided by the DAP.





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5.  Mapping Onto Transport Services

This protocol is designed to run over connection-oriented, reliable
transports, with all 8 bits in an octet being significant in the data
stream.  Specifications for two underlying services are defined here,
though others are also possible.

5.1.  Transmission Control Protocol (TCP)

The LDAPMessage PDUs are mapped directly onto the TCP bytestream.
Server implementations running over the TCP should provide a protocol
listener on port 389.

5.2.  Connection Oriented Transport Service (COTS)

The connection is established.  No special use of T-Connect is made.
Each LDAPMessage PDU is mapped directly onto T-Data.

6.  Elements of Protocol

For the purposes of protocol exchanges, all protocol operations are
encapsulated in a common envelope, the LDAPMessage, which is defined as
follows:

     LDAPMessage ::=
         SEQUENCE {
              messageID      MessageID,
              protocolOp     CHOICE {
                                  bindRequest         BindRequest,
                                  bindResponse        BindResponse,
                                  unbindRequest       UnbindRequest,
                                  searchRequest       SearchRequest,
                                  searchResponse      SearchResponse,
                                  modifyRequest       ModifyRequest,
                                  modifyResponse      ModifyResponse,
                                  addRequest          AddRequest,
                                  addResponse         AddResponse,
                                  delRequest          DelRequest,
                                  delResponse         DelResponse,
                                  modifyRDNRequest    ModifyRDNRequest,
                                  modifyRDNResponse   ModifyRDNResponse,
                                  compareRequest      CompareRequest,
                                  compareResponse     CompareResponse,
                                  abandonRequest      AbandonRequest
                             }
         }

     MessageID ::= INTEGER (0 .. maxInt)



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The function of the LDAPMessage is to provide an envelope containing
common fields required in all protocol exchanges. At this time the only
common field is a message ID, which is required to have a value dif-
ferent from the values of any other requests outstanding in the LDAP
session of which this message is a part.

The message ID value must be echoed in all LDAPMessage envelopes encap-
sulting responses corresponding to the request contained in the LDAPMes-
sage in which the message ID value was originally used.

In addition to the LDAPMessage defined above, the following definitions
are also used in defining protocol operations:

     LDAPString ::= OCTET STRING


The LDAPString is a notational convenience to indicate that, although
strings of LDAPString type encode as OCTET STRING types, the legal char-
acter set in such strings is limited to the IA5 character set.

     LDAPDN ::= LDAPString

     RelativeLDAPDN ::= LDAPString


An LDAPDN and a RelativeLDAPDN are respectively defined to be the
representation of a Distinguished Name and a Relative Distinguished Name
after encoding according to the specification in [5], such that

     <distinguished-name> ::= <name>

     <relative-distinguished-name> ::= <name-component>

where <name> and <name-component> are as defined in [5].

     AttributeValueAssertion ::=
         SEQUENCE {
              attributeType       AttributeType,
              attributeValue      AttributeValue
         }


The AttributeValueAssertion type definition  is similar to the one in
the X.500 Directory standards.

     AttributeType ::= LDAPString

     AttributeValue ::= OCTET STRING



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An AttributeType value takes on as its value the textual string associ-
ated with that AttributeType in Section 4 of [6].  For example, the
AttributeType commonName with object identifier 2.5.4.3 is represented
as an AttributeType in this protocol by the string "cn".  In the event
that a protocol implementation encounters an Attribute Type with which
it cannot associate a textual string, an ASCII string encoding of the
object identifier associated with the Attribute Type may be subsiti-
tuted.  For example, the commonName AttributeType may be represented by
the ASCII string "2.5.4.3" if a protocol implementation is unable to
associate the string "cn" with it.

The list of textual attribute names defined in Section 4 of [6] are the
only names supported, though sites may exchange other names through
bilateral agreement. A future version of this protocol may provide a
general mechanism by which supported attribute names may be extended.

A field of type AttributeValue takes on as its value an octet string
encoding of a Directory AttributeValue type. The definition of these
string encodings for different Directory AttributeValue syntaxes may be
found in [6].  These are the only syntaxes allowed in the protocol,
though others may be supported by bilateral agreement. A future version
of this protocol may provide a general mechanism by which supported
attribute syntaxes may be extended.

     LDAPResult ::=
         SEQUENCE {
             resultCode    ENUMERATED {
                             success                      (0),
                             operationsError              (1),
                             protocolError                (2),
                             timeLimitExceeded            (3),
                             sizeLimitExceeded            (4),
                             compareFalse                 (5),
                             compareTrue                  (6),
                             authMethodNotSupported       (7),
                             strongAuthRequired           (8),
                             noSuchAttributeOrValue       (16),
                             undefinedAttributeType       (17),
                             inappropriateMatching        (18),
                             constraintViolation          (19),
                             attributeOrValueExists       (20),
                             invalidAttributeSyntax       (21),
                             noSuchObject                 (32),
                             aliasProblem                 (33),
                             invalidDNSyntax              (34),
                             isLeaf                       (35),
                             aliasDereferencingProblem    (36),
                             inappropriateAuthentication  (48),



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                             invalidCredentials           (49),
                             insufficientAccessRights     (50),
                             busy                         (51),
                             unavailable                  (52),
                             unwillingToPerform           (53),
                             loopDetected                 (54),
                             namingViolation              (64),
                             objectClassViolation         (65),
                             notAllowedOnNonLeaf          (66),
                             notAllowedOnRDN              (67),
                             entryAlreadyExists           (68),
                             objectClassModsProhibited    (69),
                             other                        (80) },
             matchedDN     LDAPDN, errorMessage  LDAPString }

The LDAPResult is the construct used in this protocol to return success
or failure indications from servers to clients. In response to various
requests, servers will return responses containing fields of type
LDAPResult to indicate the final status of a protocol operation request.
The errorMessage field of this construct may, at the servers option, be
used to return an ASCII string containing a textual, human-readable
error diagnostic. As this error diagnostic is not standardized, imple-
mentations should not rely on the values returned.  If the server
chooses not to return a textual diagnostic, the errorMessage field of
the LDAPResult type should contain a zero length string.

For resultCodes of noSuchObject, aliasProblem, invalidDNSyntax, isLeaf,
and aliasDereferencingProblem, the matchedDN field is set to the name of
the lowest entry (object or alias) in the DIT that was matched and is a
truncated form of the name provided or, if an alias has been derefer-
enced, of the resulting name.  The matchedDN field should be set to NULL
DN (a zero length string) in all other cases.

Note that the resultCodes are not sequential in value.  X.500 defines
different categories of errors (e.g., NameError, AttributeError, etc.).
The resultCodes are constructed so that a simple and efficient bit
operation can be performed to determine the error category.

6.1.  Bind Operation

The function of the Bind Operation is to initiate a protocol session
between a client and a server, and to allow the authentication of the
client to the server. The Bind Operation must be the first operation
request received by a server from a client in a protocol session.  The
Bind Request is defined as follows:

     BindRequest ::=
         [APPLICATION 0] SEQUENCE {



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                             version   INTEGER (1 .. 127),
                             name      LDAPDN,
                             authentication CHOICE {
                                  simple        [0] OCTET STRING
                               -- more choices possible in a future version
                               -- tag [1] reserved
                               -- tag [2] reserved
                             }
         }

Parameters of the Bind Request are:

-    version: A version number indicating the version of the protocol to
     be used in this protocol session.  This document describes version
     2 of the LDAP protocol.  Note that there is no version negotiation,
     and the client should just set this parameter to the version it
     desires.

-    name: The name of the Directory object that the client wishes to
     bind as.  This field may take on a null value (a zero length
     string) for the purposes of anonymous binds.

-    authentication: information used to authenticate the name, if any,
     provided in the Bind Request. The ``simple'' authentication option
     provides minimal authentication facilities, with the contents of
     the authentication field consisting only of a cleartext password.
     This option should also be used when unauthenticated or anonymous
     binds are to be performed, with the field containing a zero length
     string in such cases. Sites may use other choices in the authenti-
     cation field by bilateral agreement.  Authentication choices with
     tags [1] and [2] are reserved for compatibility with existing
     clients that use those tags for non-standard authentication using
     Kerberos version 4 [7].

The Bind Operation requires a response, the Bind Response, which is
defined as:

     BindResponse ::= [APPLICATION 1] LDAPResult

A Bind Response consists simply of an indication from the server of the
status of the client's request for the initiation of a protocol session.

Upon receipt of a Bind Request, a protocol server will authenticate the
requesting client if necessary, and attempt to set up a protocol session
with that client. The server will then return a Bind Response to the
client indicating the status of the session setup request.





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6.2.  Unbind Operation

The function of the Unbind Operation is to terminate a protocol session.
The Unbind Operation is defined as follows:

     UnbindRequest ::= [APPLICATION 2] NULL

The Unbind Operation has no response defined. Upon transmission of an
UnbindRequest, a protocol client may assume that the protocol session is
terminated. Upon receipt of an UnbindRequest, a protocol server may
assume that the requesting client has terminated the session and that
all outstanding requests may be discarded.

6.3.  Search Operation

The Search Operation allows a client to request that a search be per-
formed on its behalf by a server. The Search Request is defined as fol-
lows:

     SearchRequest ::=
         [APPLICATION 3] SEQUENCE {
             baseObject    LDAPDN,
             scope         ENUMERATED {
                                baseObject            (0),
                                singleLevel           (1),
                                wholeSubtree          (2)
                           },
             derefAliases  ENUMERATED {
                                        neverDerefAliases     (0),
                                        derefInSearching      (1),
                                        derefFindingBaseObj   (2),
                                        derefAlways           (3)
                                   },
             sizeLimit     INTEGER (0 .. maxInt),
             timeLimit     INTEGER (0 .. maxInt),
             attrsOnly     BOOLEAN,
             filter        Filter,
             attributes    SEQUENCE OF AttributeType
     }

     Filter ::=
         CHOICE {
             and                [0] SET OF Filter,
             or                 [1] SET OF Filter,
             not                [2] Filter,
             equalityMatch      [3] AttributeValueAssertion,
             substrings         [4] SubstringFilter,
             greaterOrEqual     [5] AttributeValueAssertion,



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             lessOrEqual        [6] AttributeValueAssertion,
             present            [7] AttributeType,
             approxMatch        [8] AttributeValueAssertion
         }

     SubstringFilter
         SEQUENCE {
             type               AttributeType,
             SEQUENCE OF CHOICE {
                 initial        [0] LDAPString,
                 any            [1] LDAPString,
                 final          [2] LDAPString
             }
         }

Parameters of the Search Request are:

-    baseObject: An LDAPDN that is the base object entry relative to
     which the search is to be performed.

-    scope: An indicator of the scope of the search to be performed. The
     semantics of the possible values of this field are identical to the
     semantics of the scope field in the Directory Search Operation.

-    derefAliases: An indicator as to how alias objects should be han-
     dled in searching.  The semantics of the possible values of this
     field are, in order of increasing value:

          neverDerefAliases: do not dereference aliases in search-
          ing or in locating the base object of the search;

          derefInSearching: dereference aliases in subordinates of
          the base object in searching, but not in locating the
          base object of the search;

          derefFindingBaseObject: dereference aliases in locating
          the base object of the search, but not when searching
          subordinates of the base object;

          derefAlways: dereference aliases both in searching and in
          locating the base object of the search.

-    sizelimit: A sizelimit that restricts the maximum number of entries
     to be returned as a result of the search. A value of 0 in this
     field indicates that no sizelimit restrictions are in effect for
     the search.

-    timelimit: A timelimit that restricts the maximum time (in seconds)



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     allowed for a search. A value of 0 in this field indicates that no
     timelimit restrictions are in effect for the search.

-    attrsOnly: An indicator as to whether search results should contain
     both attribute types and values, or just attribute types.  Setting
     this field to TRUE causes only attribute types (no values) to be
     returned.  Setting this field to FALSE causes both attribute types
     and values to be returned.

-    filter: A filter that defines the conditions that must be fulfilled
     in order for the search to match a given entry.

-    attributes: A list of the attributes from each entry found as a
     result of the search to be returned. An empty list signifies that
     all attributes from each entry found in the search are to be
     returned.

The results of the search attempted by the server upon receipt of a
Search Request are returned in Search Responses, defined as follows:

     Search Response ::=
         CHOICE {
              entry          [APPLICATION 4] SEQUENCE {
                                  objectName     LDAPDN,
                                  attributes     SEQUENCE OF SEQUENCE {
                                                      AttributeType,
                                                      SET OF AttributeValue
                                                 }
                             },
              resultCode     [APPLICATION 5] LDAPResult
          }

Upon receipt of a Search Request, a server will perform the necessary
search of the DIT.

The server will return to the client a sequence of responses comprised
of:

-    Zero or more Search Responses each consisting of an entry found
     during the search; with the response sequence terminated by

-    A single Search Response containing an indication of success, or
     detailing any errors that have occurred.

Each entry returned will contain all attributes, complete with associ-
ated values if necessary, as specified in the 'attributes' field of the
Search Request.




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Note that an X.500 ``list'' operation can be emulated by a one-level
LDAP search operation with a filter checking for the existence of the
objectClass attribute, and that an X.500 ``read'' operation can be emu-
lated by a base object LDAP search operation with the same filter.

6.4.  Modify Operation

The Modify Operation allows a client to request that a modification of
the DIB be performed on its behalf by a server.  The Modify Request is
defined as follows:

     ModifyRequest ::=
         [APPLICATION 6] SEQUENCE {
              object         LDAPDN,
              modification   SEQUENCE OF SEQUENCE {
                                  operation      ENUMERATED {
                                                      add       (0),
                                                      delete    (1),
                                                      replace   (2)
                                                 },
                                  modification   SEQUENCE {
                                                    type    AttributeType,
                                                    values  SET OF
                                                              AttributeValue
                                                 }
                             }
         }

Parameters of the Modify Request are:

-    object: The object to be modified. The value of this field should
     name the object to be modified after all aliases have been derefer-
     enced. The server will not perform any alias dereferencing in
     determining the object to be modified.

-    A list of modifications to be performed on the entry to be modi-
     fied.  The entire list of entry modifications should be performed
     in the order they are listed, as a single atomic operation.  While
     individual modifications may violate the Directory schema, the
     resulting entry after the entire list of modifications is performed
     must conform to the requirements of the Directory schema. The
     values that may be taken on by the 'operation' field in each modif-
     ication construct have the following semantics respectively:-

          add: add values listed to the given attribute, creating
          the attribute if necessary;

          delete: delete values listed from the given attribute,



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     removing the entire attribute if no values are listed, or
     if all current values of the attribute are listed for
     deletion;

     replace: replace existing values of the given attribute
     with the new values listed, creating the attribute if
     necessary.

The result of the modify attempted by the server upon receipt of a
Modify Request is returned in a Modify Response, defined as follows:

     ModifyResponse ::= [APPLICATION 7] LDAPResult

Upon receipt of a Modify Request, a server will perform the necessary
modifications to the DIB.

The server will return to the client a single Modify Response indicating
either the successful completion of the DIB modification, or the reason
that the modification failed. Note that due to the requirement for atom-
icity in applying the list of modifications in the Modify Request, the
client may expect that no modifications of the DIB have been performed
if the Modify Response received indicates any sort of error, and that
all requested modifications have been performed if the Modify Response
indicates successful completion of the Modify Operation.


6.5.  Add Operation

The Add Operation allows a client to request the addition of an entry
into the Directory. The Add Request is defined as follows:

     AddRequest ::=
         [APPLICATION 8] SEQUENCE {
              entry          LDAPDN,
              attrs          SEQUENCE OF SEQUENCE {
                                  type          AttributeType,
                                  values        SET OF AttributeValue
                             }
         }

Parameters of the Add Request are:

-    entry: the Distinguished Name of the entry to be added. Note that
     all components of the name except for the last RDN component must
     exist for the add to succeed.

-    attrs: the list of attributes that make up the content of the entry
     being added.



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The result of the add attempted by the server upon receipt of a Add
Request is returned in the Add Response, defined as follows:

     AddResponse ::= [APPLICATION 9] LDAPResult

Upon receipt of an Add Request, a server will attempt to perform the add
requested. The result of the add attempt will be returned to the client
in the Add Response.

6.6.  Delete Operation

The Delete Operation allows a client to request the removal of an entry
from the Directory. The Delete Request is defined as follows:

     DelRequest ::= [APPLICATION 10] LDAPDN

The Delete Request consists only of the Distinguished Name of the entry
to be deleted.  The result of the delete attempted by the server upon
receipt of a Delete Request is returned in the Delete Response, defined
as follows:

     DelResponse ::= [APPLICATION 11] LDAPResult

Upon receipt of a Delete Request, a server will attempt to perform the
entry removal requested. The result of the delete attempt will be
returned to the client in the Delete Response. Note that only leaf
objects may be deleted with this operation.

6.7.  Modify RDN Operation

The Modify RDN Operation allows a client to change the last component of
the name of an entry in the Directory. The Modify RDN Request is defined
as follows:

     ModifyRDNRequest ::=
         [APPLICATION 12] SEQUENCE {
              entry          LDAPDN,
              newrdn         RelativeLDAPDN,
              deleteoldrdn   BOOLEAN
         }

Parameters of the Modify RDN Request are:

-    entry: the name of the entry to be changed.

-    newrdn: the RDN that will form the last component of the new name.

-    deleteoldrdn: a boolean parameter that controls whether the old RDN



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     attribute values should be retained as attributes of the entry or
     deleted from the entry.

The result of the name change attempted by the server upon receipt of a
Modify RDN Request is returned in the Modify RDN Response, defined as
follows:

     ModifyRDNResponse ::= [APPLICATION 13] LDAPResult

Upon receipt of a Modify RDN Request, a server will attempt to perform
the name change. The result of the name change attempt will be returned
to the client in the Modify RDN Response. The attributes that make up
the old RDN are deleted from the entry, or kept, depending on the set-
ting of the deleteoldrdn parameter.

6.8.  Compare Operation

The Compare Operation allows a client to compare an assertion provided
with an entry in the Directory. The Compare Request is defined as fol-
lows:

     CompareRequest ::=
         [APPLICATION 14] SEQUENCE {
              entry          LDAPDN,
              ava            AttributeValueAssertion
         }

Parameters of the Compare Request are:

-    entry: the name of the entry to be compared with.

-    ava: the assertion with which the entry is to be compared.

The result of the compare attempted by the server upon receipt of a Com-
pare Request is returned in the Compare Response, defined as follows:

     CompareResponse ::= [APPLICATION 15] LDAPResult

Upon receipt of a Compare Request, a server will attempt to perform the
requested comparison. The result of the comparison will be returned to
the client in the Compare Response. Note that errors and the result of
comparison are all returned in the same construct.

6.9.  Abandon Operation

The function of the Abandon Operation is to allow a client to request
that the server abandon an outstanding operation.  The Abandon Request
is defined as follows:



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     AbandonRequest ::= [APPLICATION 16] MessageID

There is no response defined in the Abandon Operation. Upon transmission
of an Abandon Operation, a client may expect that the operation identi-
fied by the Message ID in the Abandon Request has been abandoned. In the
event that a server receives an Abandon Request on a Search Operation in
the midst of transmitting responses to that search, that server should
cease transmitting responses to the abandoned search immediately.

7.  Protocol Element Encodings

The protocol elements of LDAP are encoded for exchange using the Basic
Encoding Rules (BER) [12] of ASN.1 [11]. However, due to the high over-
head involved in using certain elements of the BER, the following addi-
tional restrictions are placed on BER-encodings of LDAP protocol ele-
ments:

(1)  Only the definite form of length encoding will be used.

(2)  Bitstrings and octet strings and all character string types will be
     encoded in the primitive form only.

8.  Security Considerations

This version of the protocol provides facilities only for simple authen-
tication using a cleartext password.  Future versions of LDAP will
likely include support for other authentication methods.

9.  Bibliography

[1]  The Directory: Overview of Concepts, Models and Service.  CCITT
     Recommendation X.500, 1988

[2]  Information Processing Systems -- Open Systems Interconnection --
     The Directory: Overview of Concepts, Models and Service.  ISO/IEC
     JTC 1/SC21; International Standard 9594-1, 1988

[3]  Directory Assistance Service.  M.T. Rose; RFC 1202, February 1991.

[4]  DIXIE protocol specification.  T. Howes, M. Smith, B. Beecher; RFC
     1249, August 1991.

[5]  A String Representation of Distinguished Names.  Steve Kille; RFC
     1779

[6]  The String Representation of Standard Attribute Syntaxes.  T.
     Howes, S. Kille, W. Yeong, C.J. Robbins, M. Wahl; RFC XXXX




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[7]  Kerberos Authentication and Authorization System.  S.P. Miller,
     B.C. Neuman, J.I. Schiller, J.H. Saltzer; MIT Project Athena Docu-
     mentation Section  E.2.1, December 1987

[8]  The Directory: Models.  CCITT Recommendation X.501 ISO/IEC JTC
     1/SC21; International Standard 9594-2, 1988

[10] The Directory: Abstract Service Definition.  CCITT Recommendation
     X.511, ISO/IEC JTC 1/SC21; International Standard 9594-3, 1988

[11] Specification of Abstract Syntax Notation One (ASN.1).  CCITT
     Recommendation X.208, 1988.

[12] Specification of Basic Encoding Rules for Abstract Syntax Notation
     One (ASN.1).  CCITT Recommendation X.209, 1988.

[13] Information Processing Systems - Open Systems Interconnection,
     "Transport Service Definition", International Organization for
     Standardization, International Standard 8072, June 1986.

10.  Author's Addresses

   Wengyik Yeong
   PSI Inc.
   510 Huntmar Park Drive
   Herndon, VA 22070
   USA
   +1 703-450-8001
   yeongw@psilink.com

   Tim Howes
   University of Michigan
   ITD Research Systems
   535 W William St.
   Ann Arbor, MI 48103-4943
   USA
   +1 313 747-4454
   tim@umich.edu

   Steve Kille
   ISODE Consortium
   The Dome, The Square
   Richmond
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LDAP                                                            May 1996


                               Appendix A
                       Complete ASN.1 Definition



Lightweight-Directory-Access-Protocol DEFINITIONS IMPLICIT TAGS ::=

BEGIN

LDAPMessage ::=
    SEQUENCE {
         messageID      MessageID,
                        -- unique id in request,
                        -- to be echoed in response(s)
         protocolOp     CHOICE {
                             searchRequest       SearchRequest,
                             searchResponse      SearchResponse,
                             modifyRequest       ModifyRequest,
                             modifyResponse      ModifyResponse,
                             addRequest          AddRequest,
                             addResponse         AddResponse,
                             delRequest          DelRequest,
                             delResponse         DelResponse,
                             modifyDNRequest     ModifyDNRequest,
                             modifyDNResponse    ModifyDNResponse,
                             compareRequest      CompareRequest,
                             compareResponse     CompareResponse,
                             bindRequest         BindRequest,
                             bindResponse        BindResponse,
                             abandonRequest      AbandonRequest,
                             unbindRequest       UnbindRequest
                        }
    }

BindRequest ::=
    [APPLICATION 0] SEQUENCE {
         version        INTEGER (1 .. 127),
                        -- current version is 2
         name           LDAPDN,
                        -- null name implies an anonymous bind
         authentication CHOICE {
                             simple        [0] OCTET STRING,
                                       -- a zero length octet string
                                       -- implies an unauthenticated
                                       -- bind.
                             krbv42LDAP    [1] OCTET STRING,
                             krbv42DSA     [2] OCTET STRING
                                       -- values as returned by krb_mk_req()



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                                       -- Other values in later versions
                                       -- of this protocol.
                        }
    }

BindResponse ::= [APPLICATION 1] LDAPResult

UnbindRequest ::= [APPLICATION 2] NULL

SearchRequest ::=
    [APPLICATION 3] SEQUENCE {
         baseObject     LDAPDN,
         scope          ENUMERATED {
                             baseObject            (0),
                             singleLevel           (1),
                             wholeSubtree          (2)
                        },
         derefAliases   ENUMERATED {
                             neverDerefAliases     (0),
                             derefInSearching      (1),
                             derefFindingBaseObj   (2),
                             alwaysDerefAliases    (3)
                        },
         sizeLimit      INTEGER (0 .. maxInt),
                        -- value of 0 implies no sizelimit
         timeLimit      INTEGER (0 .. maxInt),
                        -- value of 0 implies no timelimit
         attrsOnly     BOOLEAN,
                        -- TRUE, if only attributes (without values)
                        -- to be returned.
         filter         Filter,
         attributes     SEQUENCE OF AttributeType
    }

SearchResponse ::=
    CHOICE {
         entry          [APPLICATION 4] SEQUENCE {
                             objectName     LDAPDN,
                             attributes     SEQUENCE OF SEQUENCE {
                                              AttributeType,
                                              SET OF
                                                AttributeValue
                                            }
                        },
         resultCode     [APPLICATION 5] LDAPResult
    }

ModifyRequest ::=



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    [APPLICATION 6] SEQUENCE {
         object         LDAPDN,
         modifications  SEQUENCE OF SEQUENCE {
                             operation     ENUMERATED {
                                             add      (0),
                                             delete   (1),
                                             replace  (2)
                                           },
                             modification  SEQUENCE {
                                             type     AttributeType,
                                             values   SET OF
                                                        AttributeValue
                                           }
                        }
    }


ModifyResponse ::= [APPLICATION 7] LDAPResult

AddRequest ::=
    [APPLICATION 8] SEQUENCE {
         entry          LDAPDN,
         attrs          SEQUENCE OF SEQUENCE {
                             type          AttributeType,
                             values        SET OF AttributeValue
                        }
    }

AddResponse ::= [APPLICATION 9] LDAPResult

DelRequest ::= [APPLICATION 10] LDAPDN

DelResponse ::= [APPLICATION 11] LDAPResult

ModifyRDNRequest ::=
    [APPLICATION 12] SEQUENCE {
         entry          LDAPDN,
         newrdn         RelativeLDAPDN -- old RDN always deleted
    }

ModifyRDNResponse ::= [APPLICATION 13] LDAPResult

CompareRequest ::=
    [APPLICATION 14] SEQUENCE {
         entry          LDAPDN,
         ava            AttributeValueAssertion
    }




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CompareResponse ::= [APPLICATION 15] LDAPResult

AbandonRequest ::= [APPLICATION 16] MessageID

MessageID ::= INTEGER (0 .. maxInt)

LDAPDN ::= LDAPString

RelativeLDAPDN ::= LDAPString

Filter ::=
    CHOICE {
        and            [0] SET OF Filter,
        or             [1] SET OF Filter,
        not            [2] Filter,
        equalityMatch  [3] AttributeValueAssertion,
        substrings     [4] SubstringFilter,
        greaterOrEqual [5] AttributeValueAssertion,
        lessOrEqual    [6] AttributeValueAssertion,
        present        [7] AttributeType,
        approxMatch    [8] AttributeValueAssertion
    }

LDAPResult ::=
    SEQUENCE {
        resultCode    ENUMERATED {
                        success                      (0),
                        operationsError              (1),
                        protocolError                (2),
                        timeLimitExceeded            (3),
                        sizeLimitExceeded            (4),
                        compareFalse                 (5),
                        compareTrue                  (6),
                        authMethodNotSupported       (7),
                        strongAuthRequired           (8),
                        noSuchAttribute              (16),
                        undefinedAttributeType       (17),
                        inappropriateMatching        (18),
                        constraintViolation          (19),
                        attributeOrValueExists       (20),
                        invalidAttributeSyntax       (21),
                        noSuchObject                 (32),
                        aliasProblem                 (33),
                        invalidDNSyntax              (34),
                        isLeaf                       (35),
                        aliasDereferencingProblem    (36),
                        inappropriateAuthentication  (48),
                        invalidCredentials           (49),



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                        insufficientAccessRights     (50),
                        busy                         (51),
                        unavailable                  (52),
                        unwillingToPerform           (53),
                        loopDetect                   (54),
                        namingViolation              (64),
                        objectClassViolation         (65),
                        notAllowedOnNonLeaf          (66),
                        notAllowedOnRDN              (67),
                        entryAlreadyExists           (68),
                        objectClassModsProhibited    (69),
                        other                        (80)
                      },
        matchedDN     LDAPDN,
        errorMessage  LDAPString
    }

AttributeType ::= LDAPString
                -- text name of the attribute, or dotted
                -- OID representation

AttributeValue ::= OCTET STRING

AttributeValueAssertion ::=
    SEQUENCE {
        attributeType        AttributeType,
        attributeValue       AttributeValue
    }

SubstringFilter ::=
    SEQUENCE {
        type               AttributeType,
        SEQUENCE OF CHOICE {
          initial          [0] LDAPString,
          any              [1] LDAPString,
          final            [2] LDAPString
      }
    }

LDAPString ::= OCTET STRING

maxInt INTEGER ::= 65535
END








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