LDAP em VDM++

LDAP em VDM++

Pedro Pereira Ulisses Costa

Metodos Formais em Engenharia de Software

12 de Fevereiro de 2009

Pedro Pereira, Ulisses Costa LDAP em VDM++

Sumario

1 LDAPO que e o LDAP e a DITEstrutura do LDAPPropriedades do LDAP

2 VDMDIT - Tree? & ForestServidor

3 Operacoes do Servidor


Sumario





LDAP

LDAP vs DAP - Lightweight porque opera em TCP/IP

LDAP e pelo menos uma DIT

Uma directoria e uma maneira de organizar informacaocomplexa, tornando facil a sua pesquisa.


Sumario





Estrutura da DIT

Funcao da DIT

Guardar a hierarquia

Composta por entradas

Entradas sao instancias de ObjectClass

ObjectClass’s podem ter atributos

Atributos relacionam a informacao


Estrutura das entradas

Contem uma instancia de ObjectClass

Atributos obrigatorios da ObjectClass

Um DN (Distinguished Name))

Unico em toda a arvore

Um RDN (Relative Distinguished Name)

Unico entre irmaos


Sumario





Propriedades do LDAP

Floresta de DIT’s

DN’s sao unicos na DIT

Um DN e: O DN do antecessor e o seu RDN

Cada atributo tem pares de (identificador,valor)


Sumario





Sumario





DIT - Tree?

Grafo acıclico e ligado (uma raız)

The root of the DIT is a DSA-specific Entry (DSE) and notpart of any naming context


DIT - Forest

Grafo acıclico e nao ligado (multiplas raızes)


Sumario





Servidor Estrutura

class Server

types

public String = seq of char;

public OName = String;

public AName = String;

public Value = String;

public ObjClass :: must : set of AName

may : set of AName;

instance variables

private entries : map nat1 to Entry; -- entradas existentesprivate dit : map nat1 to set of nat1; -- hierarquia das entradasprivate def_objs : map OName to ObjClass; -- objectos definidosprivate def_attrs : set of AName; -- atributos definidos

inv ServerINV ();


Servidor Invariantes

The root of the DIT is a DSA-specific Entry (DSE) and not part of any namingcontext;

Entries have names: one or more attribute values from the entry form its relativedistinguished name (RDN), which MUST be unique among all its siblings;

The concatenation of the relative distinguished names of the sequence of entriesfrom a particular entry to an immediate subordinate of the root of the treeforms that entry’s Distinguished Name (DN), which is unique in the tree;

Each entry MUST have an objectClass attribute which specifies the objectclasses of that entry ;

Servers MUST NOT permit clients to add attributes to an entry unless thoseattributes are permitted by the object class definitions, the schema controllingthat entry ;

Entries consist of a set of attributes;

An attribute is a type with one or more associated values and is identified by ashort descriptive name (...);

Schema is the collection of attribute type definitions, object class definitions andother information (...);


Servidor Invariantes

public ServerINV: () ==> bool

ServerINV () ==

(

return (

-- dit aciclica( not exists e in set dom dit & e in set TransitiveClosure(e) ) and

-- todos os elementos que existem estao na dit( forall e in set ( dom dit union rng dit ) & e in set dom entries ) and

-- objectos apenas contem atributos definidos( forall o in set rng def_objs & ( forall a in set ( o.must union o.may

) & a in set def_attrs ) ) and

-- dn unico entre todos os elementos da floresta( forall e1, e2 in set rng entries & e1.GetDN() <> e2.GetDN () ) and

-- dn do pai contido no do filho( forall p in set dom dit & ( forall c in set TransitiveClosure(p) & (

elems entries(c).GetDN() ) subset ( elems entries(p).GetDN() ) ) )

and

-- rdn unico entre irmaos( forall p in set dom dit & ( forall c1, c2 in set dit(p) & entries(c1).

GetRDN () <> entries(c2).GetRDN () ) ) and

-- rdn faz parte do dn( forall e in set rng entries & e.GetRDN () in set elems e.GetDN () ) and

-- rdn composto por um atributo( forall e in set rng entries & e.GetRDN () in set dom e.GetAttrs () )));


Sumario





Servidor Operacoes

CRUD

Create Read Update Delete

Add Entry

Del Entry

Modify DN

Search Entry

Search Attributes


Modify DN

public ModDN: seq of AName * AName ==> ()

ModDN(old_dn , new_rdn) ==

(

dcl new_dn: seq of AName := [];

dcl pos: nat1 := len old_dn - 1;

dcl e: nat1 := GetID(old_dn);

for i = 1 to pos do

new_dn := new_dn ^ [old_dn(i)];

new_dn := new_dn ^ [new_rdn ];

entries(e).SetDN(new_dn);

for all c in set TransitiveClosure(e) do

(

new_dn := [];

for i = 1 to ( len entries(c).GetDN () ) do

if i = pos

then new_dn := new_dn ^ [new_rdn]

else new_dn := new_dn ^ entries(c).GetDN ()(i);

entries(c).SetDN(new_dn);

);

)

pre ( exists i in set dom entries & entries(i).GetDN() = old_dn )

post ( exists i in set dom entries & forall c in set TransitiveClosure(i) &

new_rdn in set elems entries(i).GetDN() and new_rdn in set elems entries(c)

.GetDN() );


GetID

public GetID: seq of AName ==> nat

GetID(dn) ==

(

for all i in set dom entries do

if entries(i).GetDN() = dn

then return i;

return 0;

)

post ( not exists i in set dom entries & entries(i).GetDN() = dn => RESULT = 0 )

or

( exists i in set dom entries & entries(i).GetDN() = dn => RESULT = i );


Transitive Closure

public TransitiveClosure: nat1 ==> set of nat1

TransitiveClosure(origem) ==

(

dcl res: set of nat1 := {};

dcl childs: set of nat1 := dit(origem);

while childs <> {} do

(

for all c in set childs do

(

childs := childs union dit(c);

res := res union {c};

);

childs := childs \ res;

);

return res;

)

pre origem in set dom entries

post forall e in set RESULT & ( elems entries(origem).GetDN() ) subset ( elems

entries(e).GetDN() );


Technology

LDAP em VDM++