





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





















Johansson                                                                    [Page 6]


