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 *               2009-2016 Université Paris-Sud, France
 *               2015-2016 The University of Sheffield, UK
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subsection {* DMZ Datatype *}
theory 
  DMZDatatype
imports 
    "../../UPF-Firewall"
begin

text{* This is the fourth scenario, slightly more complicated than the
previous one, as we now also model specific servers within one
network. Therefore, we could not use anymore the modelling using
datatype synonym, but only use the one where an address is modelled as an
integer (with ports). 

Just for comparison, this theory is the same scenario with datatype synonym
anyway, but with four distinct networks instead of one contained in
another. As there is no corresponding network model included, we need
to define a custom one.  *}


datatype Adr = Intranet | Internet | Mail | Web | DMZ
instance Adr::adr ..
type_synonym port = int
type_synonym Networks = "Adr \<times> port"


definition
  intranet::"Networks net" where
 "intranet = {{(a,b). a= Intranet}}"
definition
  dmz :: "Networks net" where
 "dmz = {{(a,b). a= DMZ}}"
definition
  mail :: "Networks net" where
 "mail = {{(a,b). a=Mail}}" 
definition
  web :: "Networks net" where
 "web = {{(a,b). a=Web}}" 
definition
  internet :: "Networks net" where 
 "internet = {{(a,b). a= Internet}}"

definition 
  Intranet_mail_port :: "(Networks ,DummyContent) FWPolicy" where
  "Intranet_mail_port = (allow_from_ports_to {21::port,14} intranet mail)" 

definition
  Intranet_Internet_port :: "(Networks,DummyContent) FWPolicy" where
  "Intranet_Internet_port = allow_from_ports_to {80::port,90} intranet internet"
     
definition
  Internet_web_port :: "(Networks,DummyContent) FWPolicy" where
  "Internet_web_port = (allow_from_ports_to {80::port,90} internet web)"
          
definition
  Internet_mail_port :: "(Networks,DummyContent) FWPolicy" where
  "Internet_mail_port =  (allow_all_from_port_to internet (21::port) dmz)"

definition 
  policyPort :: "(Networks, DummyContent) FWPolicy" where
 "policyPort = deny_all ++ 
                  Intranet_Internet_port ++ 
                  Intranet_mail_port ++  
                  Internet_mail_port ++ 
                  Internet_web_port"


text {* We only want to create test cases which are sent between the
three main networks --- e.g. not between the mailserver and the
dmz. Therefore, the constraint looks as follows. *}

definition
 not_in_same_net :: "(Networks,DummyContent) packet \<Rightarrow> bool" where
 "not_in_same_net x  =  ((src x \<sqsubset> internet \<longrightarrow> \<not> dest x \<sqsubset> internet) \<and> 
                        (src x \<sqsubset> intranet \<longrightarrow> \<not> dest x \<sqsubset> intranet) \<and> 
                        (src x \<sqsubset> dmz \<longrightarrow> \<not> dest x \<sqsubset> dmz))"

lemmas PolicyLemmas =   dmz_def internet_def intranet_def mail_def web_def 
                       Internet_web_port_def Internet_mail_port_def
                       Intranet_Internet_port_def Intranet_mail_port_def 
                       src_def dest_def src_port dest_port in_subnet_def


end
