INTERNET-DRAFT                                                         Leif Johansson
Intented Category: Experimental                                  Stockholm University



           A directory (X.500 and LDAPv3) schema for Berkely automounter


1. Status of this Memo

  This memo describes a directory (LDAP or X.500) schema for storing amd (Berkely-
  style automounter) mount info maps. The schema is currently beeing supported by
  the (beta version of the) am-utils version 6 package [AMUTILS].

2. Overview and Rationale

  Directory services such as X.500 [X500] or LDAP [RFC2251] are a natural choice of
  repository for amd mount map databases. All Object Identifiers in this document
  are prefixed by amdSchema-id to be assigned later. The relation between this
  schema and the automount schema elements in [HOWARD] are mostly superficial. The
  model for the elements in [HOWARD] was the SUN automounter which has quite a
  different syntax for mount maps. Furthermore the intended usage of this schema
  differs from that of [HOWARD] in many respects.

3. DSA requirements

  Directory servers implementing this schema SHOULD maintain the modifyTimestamp
  operational attribute. If not the amdMapCacheTtl attribute SHOULD be set to 0
  indicating to clients that caching of map entries SHOULD be turned off. Clients
  wishing to use the amdMap schema MAY use the modifyTimestamp information to set
  the ttl for internal caching schemes. A value of 0 for the amdMapCacheTtl must
  result in clients turning off any local caching.

4. Syntax definitions

  The following attribute syntax is defined in this document:

       amdlocationlist

  This syntax represents a amd map value. This is the syntax expressed in BNF using
  definitions from [RFC2252]:

       amdlocationlist      = amdlocationselection |
                              amdlocationlist whsp "||" whsp amdlocationselection

       amdlocationselection = amdlocation |
                              amdlocationselection whsp amdlocation




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       amdlocation          = amdlocationinfo |
                              "-" amdlocationinfo |
                              "-"

       amdlocationinfo      = seloropt |
                              amdlocationinfo ";" seloropt |
                              ";"

       seloropt             = seletion |
                              optass

       selection            = keystring "==" printablestring
                              keystring "!=" printablestring

       optass               = keystring

  X.500 servers or LDAPv3 servers (supporting the binary attribute option) may use
  the following syntax definition:

       AmdLocationList ::= SEQUENCE OF {
                              SEQUENCE OF {
                                 location     AmdLocation
                              }
                           }

       AmdLocation     ::= SET OF {
                              CHOICE {
                                 location     [0] AmdLocationInfo
                                 notlocation  [1] AmdLocationInfo
                                 not          [2] NULL
                              }
                           }

       AmdLocationInfo ::= SET OF {
                              CHOICE {
                                 selection    [0] AmdSelection
                                 option       [1] AmdOption
                              }
                           }

       AmdSelection    ::= CHOICE {
                              eq     [0] AttributeAndValue
                              ne     [1] AttributeAndValue
                           }

       AmdOption       ::= AttributeAndValue
       AttributeAndValue ::= SEQUENCE {
                                attribute     IA5String



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                                value         IA5String
                             }

5. Attribute types

  The following attribute types are defined in this document:

       amdMapName
       amdMapCacheTtl
       amdMapEntry
       amdMapEntryKey
       amdMapEntryValue

       amdSchema-a OBJECT IDENTIFIER ::= { amdSchema-id 1 }

       amdMapName      ATTRIBUTE ::= {
             WITH SYNTAX              IA5String
             EQUALITY MATCHING RULE   caseIgoreExactMatch
             --ID                     { amdSchema-a 1 }
             DESCRIPTION
              "This attribute is the symbolic and in the naming
               context unique name of an amd map. This corresponds
               in the case of a flat file database to the name of
               the file or the mount-point of the map."
          }


       amdMapCacheTtl
          ATTRIBUTE ::= {
             WITH SYNTAX              Integer
             EQUALITY MATCHING RULE   integerExactMatch
             --ID                     { amdSchema-a 2 }
             SINGLE VALUED
             DESCRIPTION
              "The maximum time-to-live for the entries in this
               map. After this many milliseconds the map has to
               be cleared from local caches and reloaded. A value
               of 0 disables caching."
          }

       amdMapEntry
          ATTRIBUTE ::= {
             WITH SYNTAX              DistinguishedName
             EQUALITY MATHCING RULE   dNCaseIgnoreExactMatch
             --ID                     { amdSchema-a 3 }
             DESCRIPTION
              "A multivalued attribute listing the distinguished
               names of the amdMapEntries making up this amdMap



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               object."
          }

       amdMapEntryKey ::= {
          ATTRIBUTE ::= {
             WITH SYNTAX              IA5String
             EQUALITY MATCHING RULE   stringExactMatch
             --ID                     { amdSchema-a 4 }
             SINGLE VALUED
             DESCRIPTION
              "The value of this attribute is usually the name of
               a mountpoint for this amdMapEntry."
          }

       amdMapEntryValue ::= {
          ATTRIBUTE ::= {
             WITH SYNTAX              AmdLocationList
             --ID                     { amdSchema-a 5 }
             DESCRIPTION
              "This is the actual mount information for the amdMapEntry
               using the syntax described above."
          }

       amdMapEntryKey ::= {
          ATTRIBUTE ::= {
             WITH SYNTAX              IA5String
             EQUALITY MATCHING RULE   stringExactMatch
             --ID                     { amdSchema-a 4 }
             SINGLE VALUED
             DESCRIPTION
              "The value of this attribute is usually the name of
               a mountpoint for this amdMapEntry."
          }

       amdMapEntryValue ::= {
          ATTRIBUTE ::= {
             WITH SYNTAX              AmdLocationList
             --ID                     { amdSchema-a 5 }
             DESCRIPTION
              "This is the actual mount information for the amdMapEntry
               using the syntax described above."
          }

6. Object classes

  The following object classes are defined in this document:

            amdMap



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            amdMapEntry

  defined as follows:

            amdSchema-oc ::= { amdSchema-id 2 }

            amdMap OBJECT-CLASS ::= {
                      SUBCLASS OF            { top }
                      KIND                   auxiliary
                      --ID                   { amdSchema-oc 1 }
                      MAY CONTAIN            { amdMapCacheTtl , cn }
                      MUST CONTAIN           { amdMapName , amdMapEntry }
                   }

            amdMapEntry OBJECT-CLASS ::= {
                           SUBCLASS OF       { top }
                           KIND              structural
                           --ID              { amdSchema-oc 2 }
                           MUST CONTAIN      {
                                               amdMapName ,
                                               amdEntryKey ,
                                               amdEntryValue ,
                                             }                       MAY CONTAIN
  { cn }                       DESCRIPTION                     "An entry of this
  object class describes mount                         information relative to a
  certain amdMap entry"
                        }

7. Examples



8. Security Considerations

  Due to the security problems posed by NFS care should be taken not to advertise
  exported filesystems. Therefore it is often desirable to limit access to entries
  carrying amd mount map information to those systems to which the corresponding
  filesystems have been exported.

9. References

     [AMUTILS]
          am-utils homepage: http://shekel.cs.columbia.edu/~erez/am-utils.html

     [RFC2251]
          M. Wahl, T. Howes, S. Kille, "Lightweight Directory Access
          Protocol (v3)", RFC 2251, December 1997.




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     [RFC2252]
          M. Wahl, A. Coulbeck, T. Howes, S. Kille, "Lightweight Directory
          Access Protocol (v3): Attribute Syntax Definitions", RFC 2252,
          December 1997.

     [RFC2253]
          M. Wahl, S. Kille, T. Howes, "Lightweight Directory Access
          Protocol (v3): UTF-8 String Representation of Distinguished
          Names", RFC 2253, December 1997.

     [HOWARD]
          Luke Howard, "An Approach for Using LDAP as a Network
          Information Service", draft-howard-nis-schema-??.txt, Internet
          draft.

     [X500]
          ITU something or other.



Author's Address


  Leif Johansson
  Department of Mathematics
  Stockholm University
  S-106 91 Stockholm
           SWEDEN

  Email: leifj AT matematik.su.se





















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