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NAME

       diameter_dict - Dictionary interface of the diameter application.

DESCRIPTION

       A  diameter  service,  as  configured with diameter:start_service/2, specifies one or more
       supported Diameter applications. Each Diameter application specifies a  dictionary  module
       that  knows  how  to  encode and decode its messages and AVPs. The dictionary module is in
       turn generated from a file that defines these messages and AVPs. The format of such a file
       is  defined  in  FILE  FORMAT  below. Users add support for their specific applications by
       creating dictionary files, compiling them to Erlang modules using either  diameterc(1)  or
       diameter_make(3erl) and configuring the resulting dictionaries modules on a service.

       Dictionary  module  generation  also  results  in  a hrl file that defines records for the
       messages and Grouped AVPs defined by the dictionary, these records being what  a  user  of
       the diameter application sends and receives, modulo other possible formats as discussed in
       diameter_app(3erl). These records and the underlying Erlang data  types  corresponding  to
       Diameter  data  formats  are discussed in MESSAGE RECORDS and DATA TYPES respectively. The
       generated hrl also contains macro definitions for the possible  values  of  AVPs  of  type
       Enumerated.

       The  diameter  application  includes five dictionary modules corresponding to applications
       defined    in    section    2.4    of    RFC    6733:    diameter_gen_base_rfc3588     and
       diameter_gen_base_rfc6733  for  the  Diameter Common Messages application with application
       identifier 0, diameter_gen_accounting (for RFC 3588) and diameter_gen_acct_rfc6733 for the
       Diameter  Base Accounting application with application identifier 3 and diameter_gen_relay
       the Relay application with application identifier 0xFFFFFFFF.

       The Common Message and Relay applications are the only applications that  diameter  itself
       has  any  specific  knowledge of. The Common Message application is used for messages that
       diameter itself handles: CER/CEA, DWR/DWA and DPR/DPA.  The  Relay  application  is  given
       special  treatment with regard to encode/decode since the messages and AVPs it handles are
       not specifically defined.

FILE FORMAT

       A dictionary file consists of distinct sections. Each section starts with a  tag  followed
       by  zero  or  more arguments and ends at the the start of the next section or end of file.
       Tags consist of an ampersand character followed by a keyword and are separated from  their
       arguments   by  whitespace.  Whitespace  separates  individual  tokens  but  is  otherwise
       insignificant.

       The tags, their arguments and the contents of each corresponding section are  as  follows.
       Each  section  can  occur  multiple  times  unless otherwise specified. The order in which
       sections are specified is unimportant.

         @id Number:
           Defines the integer Number as the  Diameter  Application  Id  of  the  application  in
           question.  Can occur at most once and is required if the dictionary defines @messages.
           The section has empty content.

           The Application Id is  set  in  the  Diameter  Header  of  outgoing  messages  of  the
           application,  and  the  value in the header of an incoming message is used to identify
           the relevant dictionary module.

           Example:

         @id 16777231

         @name Mod:
           Defines the name of the generated dictionary  module.  Can  occur  at  most  once  and
           defaults  to  the  name of the dictionary file minus any extension if unspecified. The
           section has empty content.

           Note that a dictionary module should have  a  unique  name  so  as  not  collide  with
           existing modules in the system.

           Example:

         @name etsi_e2

         @prefix Name:
           Defines Name as the prefix to be added to record and constant names (followed by a '_'
           character) in the generated dictionary module and hrl. Can occur  at  most  once.  The
           section has empty content.

           A  prefix  is  optional but can be be used to disambiguate between record and constant
           names  resulting  from  similarly  named  messages  and  AVPs  in  different  Diameter
           applications.

           Example:

         @prefix etsi_e2

         @vendor Number Name:
           Defines  the  integer Number as the the default Vendor-Id of AVPs for which the V flag
           is set. Name documents the owner of the application but is otherwise unused. Can occur
           at most once and is required if an AVP sets the V flag and is not otherwise assigned a
           Vendor-Id. The section has empty content.

           Example:

         @vendor 13019 ETSI

         @avp_vendor_id Number:
           Defines the integer Number as the Vendor-Id of the AVPs listed in the section content,
           overriding the @vendor default. The section content consists of AVP names.

           Example:

         @avp_vendor_id 2937

         WWW-Auth
         Domain-Index
         Region-Set

         @inherits Mod:
           Defines  the  name  of  a  dictionary module containing AVP definitions that should be
           imported into the current dictionary. The section content consists  of  the  names  of
           those  AVPs  whose  definitions  should be imported from the dictionary, an empty list
           causing all to be imported. Any listed  AVPs  must  not  be  defined  in  the  current
           dictionary and it is an error to inherit the same AVP from more than one dictionary.

           Note  that  an  inherited  AVP  that  sets  the V flag takes its Vendor-Id from either
           @avp_vendor_id in the inheriting dictionary or @vendor in the inherited dictionary. In
           particular,  @avp_vendor_id  in the inherited dictionary is ignored. Inheriting from a
           dictionary that specifies the required @vendor is equivalent to  using  @avp_vendor_id
           with a copy of the dictionary's definitions but the former makes for easier reuse.

           All     dictionaries     should    typically    inherit    RFC    6733    AVPs    from
           diameter_gen_base_rfc6733.

           Example:

         @inherits diameter_gen_base_rfc6733

         @avp_types:
           Defines the name, code, type and flags of individual AVPs.  The  section  consists  of
           definitions of the form

           Name Code Type Flags

           where  Code  is the integer AVP code, Type identifies an AVP Data Format as defined in
           section DATA TYPES below, and Flags is a string of V, M and  P  characters  indicating
           the  flags  to be set on an outgoing AVP or a single '-' (minus) character if none are
           to be set.

           Example:

         @avp_types

         Location-Information   350  Grouped     MV
         Requested-Information  353  Enumerated   V

     Warning:
         The P flag has been deprecated by RFC 6733.

         @custom_types Mod:
           Specifies AVPs for which module Mod  provides  encode/decode  functions.  The  section
           contents  consists  of  AVP  names.  For each such name, Mod:Name(encode|decode, Type,
           Data) is expected to provide encode/decode for values of the AVP, where  Name  is  the
           name  of  the  AVP,  Type  is  it's  type as declared in the @avp_types section of the
           dictionary and Data is the value to encode/decode.

           Example:

         @custom_types rfc4005_avps

         Framed-IP-Address

         @codecs Mod:
           Like @custom_types but requires the specified module to export Mod:Type(encode|decode,
           Name, Data) rather than Mod:Name(encode|decode, Type, Data).

           Example:

         @codecs rfc4005_avps

         Framed-IP-Address

         @messages:
           Defines  the  messages of the application. The section content consists of definitions
           of the form specified in section 3.2 of RFC 6733, "Command Code Format Specification".

         @messages

         RTR ::= < Diameter Header: 287, REQ, PXY >
                 < Session-Id >
                 { Auth-Application-Id }
                 { Auth-Session-State }
                 { Origin-Host }
                 { Origin-Realm }
                 { Destination-Host }
                 { SIP-Deregistration-Reason }
                 [ Destination-Realm ]
                 [ User-Name ]
               * [ SIP-AOR ]
               * [ Proxy-Info ]
               * [ Route-Record ]
               * [ AVP ]

         RTA ::= < Diameter Header: 287, PXY >
                 < Session-Id >
                 { Auth-Application-Id }
                 { Result-Code }
                 { Auth-Session-State }
                 { Origin-Host }
                 { Origin-Realm }
                 [ Authorization-Lifetime ]
                 [ Auth-Grace-Period ]
                 [ Redirect-Host ]
                 [ Redirect-Host-Usage ]
                 [ Redirect-Max-Cache-Time ]
               * [ Proxy-Info ]
               * [ Route-Record ]
               * [ AVP ]

         @grouped:
           Defines the contents of the AVPs of the application having type Grouped.  The  section
           content  consists  of  definitions  of  the form specified in section 4.4 of RFC 6733,
           "Grouped AVP Values".

           Example:

         @grouped

         SIP-Deregistration-Reason ::= < AVP Header: 383 >
                                       { SIP-Reason-Code }
                                       [ SIP-Reason-Info ]
                                     * [ AVP ]

           Specifying a Vendor-Id in the definition of a grouped AVP is equivalent to  specifying
           it with @avp_vendor_id.

         @enum Name:
           Defines  values  of AVP Name having type Enumerated. Section content consists of names
           and corresponding integer values. Integer  values  can  be  prefixed  with  0x  to  be
           interpreted as hexadecimal.

           Note  that  the  AVP in question can be defined in an inherited dictionary in order to
           introduce additional values to an enumeration otherwise defined in another dictionary.

           Example:

         @enum SIP-Reason-Code

         PERMANENT_TERMINATION    0
         NEW_SIP_SERVER_ASSIGNED  1
         SIP_SERVER_CHANGE        2
         REMOVE_SIP_SERVER        3

         @end:
           Causes parsing of the dictionary to terminate: any remaining content is ignored.

       Comments can be included in a dictionary file using semicolon: characters from a semicolon
       to end of line are ignored.

MESSAGE RECORDS

       The  hrl  generated  from  a dictionary specification defines records for the messages and
       grouped AVPs defined in @messages and @grouped sections. For each message or  grouped  AVP
       definition,  a  record is defined whose name is the message or AVP name, prefixed with any
       dictionary prefix defined with @prefix, and  whose  fields  are  the  names  of  the  AVPs
       contained  in  the  message  or  grouped  AVP  in the order specified in the definition in
       question. For example, the grouped AVP

       SIP-Deregistration-Reason ::= < AVP Header: 383 >
                                     { SIP-Reason-Code }
                                     [ SIP-Reason-Info ]
                                   * [ AVP ]

       will result in the following record definition given an empty prefix.

       -record('SIP-Deregistration-Reason' {'SIP-Reason-Code',
                                            'SIP-Reason-Info',
                                            'AVP'}).

       The values encoded in the fields of generated records depends on the type  and  number  of
       times  the  AVP  can  occur. In particular, an AVP which is specified as occurring exactly
       once is encoded as a value of the AVP's type while an AVP with any other specification  is
       encoded  as  a list of values of the AVP's type. The AVP's type is as specified in the AVP
       definition, the RFC 6733 types being described below.

DATA TYPES

       The data formats defined in sections 4.2 ("Basic AVP Data Formats") and 4.3 ("Derived  AVP
       Data  Formats")  of  RFC  6733 are encoded as values of the types defined here. Values are
       passed to diameter:call/4 in a request record  when  sending  a  request,  returned  in  a
       resulting  answer  record  and  passed to a handle_request/3 callback upon reception of an
       incoming request.

       In cases in which there is a choice between string() and binary() types for  OctetString()
       and derived types, the representation is determined by the value of diameter:service_opt()
       string_decode.

       Basic AVP Data Formats

       OctetString() = string() | binary()
       Integer32()   = -2147483647..2147483647
       Integer64()   = -9223372036854775807..9223372036854775807
       Unsigned32()  = 0..4294967295
       Unsigned64()  = 0..18446744073709551615
       Float32()     = '-infinity' | float() | infinity
       Float64()     = '-infinity' | float() | infinity
       Grouped()     = record()

       On encode, an OctetString() can be specified as an iolist(), excessively large floats  (in
       absolute  value)  are equivalent to infinity or '-infinity' and excessively large integers
       result in encode failure. The records for grouped AVPs are as discussed  in  the  previous
       section.

       Derived AVP Data Formats

       Address() = OctetString()
                 | tuple()

       On  encode,  an  OctetString() IPv4 address is parsed in the usual x.x.x.x format while an
       IPv6 address is parsed in any of the formats specified by section 2.2 of RFC  2373,  "Text
       Representation  of  Addresses".  An  IPv4 tuple() has length 4 and contains values of type
       0..255. An IPv6 tuple() has length 8 and contains  values  of  type  0..65535.  The  tuple
       representation is used on decode.

       Time() = {date(), time()}

       where

         date() = {Year, Month, Day}
         time() = {Hour, Minute, Second}

         Year   = integer()
         Month  = 1..12
         Day    = 1..31
         Hour   = 0..23
         Minute = 0..59
         Second = 0..59

       Additionally,  values  that  can  be  encoded are limited by way of their encoding as four
       octets as required by RFC 6733 with the required extension from RFC 2030.  In  particular,
       only  values  between  {{1968,1,20},{3,14,8}} and {{2104,2,26},{9,42,23}} (both inclusive)
       can be encoded.

       UTF8String() = [integer()] | binary()

       List elements are the UTF-8 encodings of the individual characters in the string.  Invalid
       codepoints  will  result  in  encode/decode  failure.  On  encode,  a  UTF8String() can be
       specified as a binary, or as a nested list of binaries and codepoints.

       DiameterIdentity() = OctetString()

       A value must have length at least 1.

       DiameterURI() = OctetString()
                     | #diameter_URI{type = Type,
                                     fqdn = FQDN,
                                     port = Port,
                                     transport = Transport,
                                     protocol  = Protocol}

       where

         Type = aaa | aaas
         FQDN = OctetString()
         Port = integer()
         Transport = sctp | tcp
         Protocol  = diameter | radius | 'tacacs+'

       On encode, fields port,  transport  and  protocol  default  to  3868,  sctp  and  diameter
       respectively.  The  grammar  of  an  OctetString-valued  DiameterURI()  is as specified in
       section 4.3 of RFC 6733. The record representation is used on decode.

       Enumerated() = Integer32()

       On encode, values can be specified using the macros defined in a dictionary's hrl file.

       IPFilterRule()  = OctetString()
       QoSFilterRule() = OctetString()

       Values of these types are not currently parsed by diameter.

SEE ALSO

       diameterc(1),       diameter(3erl),       diameter_app(3erl),        diameter_codec(3erl),
       diameter_make(3erl)