[erlang-questions] erlang diameter dictionary

Anders Svensson <>
Fri Mar 22 18:27:00 CET 2013


Hi Samuel

On Fri, Mar 22, 2013 at 5:55 PM, S X <> wrote:
> Thanks a lot, Anders,
>
> I think I overlooked what the meaning of the configurable ID tag (4) in the
> dia file is , which is supposed to be the important application ID to be
> used in the configuration. Your suggestion about the prefix is also right.
> But now I am just learning erlang diameter library.
>
> I just try to follow the sample RAR message style, and am still having issue
> with sending CCR message. The client configuration now is:
>
> -define(SERVICE(Name), [{'Origin-Host', ?L(Name) ++ ".example.com"},
>                         {'Origin-Realm', "example.com"},
>                         {'Vendor-Id', 193},
>                         {'Product-Name', "Client"},
>                         {'Auth-Application-Id', [?DIAMETER_APP_ID_CCRA]},
>                         {application, [{alias, ?APP_CCR_ALIAS},
>                                        {dictionary, ?DIAMETER_DICT_CCRA},
>                                        {module, client_cb_ccra}]}]).
>
> Try to send CCR message:
>
> call(Name) ->
>     SId = diameter:session_id(?L(Name)),
>     CCR = #diameter_base_rfc4006_cc_CCR{
>         'Session-Id' = SId,
>         'Service-Context-Id' = "Test",
>         'CC-Request-Type' =
> ?'DIAMETER_BASE_RFC4006_CC_CC-REQUEST-TYPE_INITIAL_REQUEST',
>         'CC-Request-Number' = 0,
>         'Auth-Application-Id' = ?DIAMETER_APP_ID_CCRA,
>         'User-Name' = "Me"},
>     diameter:call(Name, ?APP_CCR_ALIAS, CCR, []).
>
>
> In the client callback module:
>
> prepare_request(#diameter_packet{msg = Rec}, _, {_, Caps}) ->
>     #diameter_caps{origin_host = {OH, DH},
>                    origin_realm = {OR, DR}}
>         = Caps,
>
>     {send, Rec#diameter_base_rfc4006_cc_CCR{'Origin-Host' = OH,
>                                  'Origin-Realm' = OR,
>                                  'Destination-Host' = DH,
>                                  'Destination-Realm' = DR}}.
>
> I got the error about AVP property:
>
> =ERROR REPORT==== 22-Mar-2013::00:17:31 ===
>     why: {diameter_codec,encode,
>              {{repeated_avp_excessive_arity,'Destination-Host',1,
>                   "server.example.com",'CCR'},

This is because Destination-Host is optional in CCR and AVP's are
encoded differently in a message record depending on whether or not
there can be exactly one occurrence: if so then the field value should
be the AVP value, if not then a list of AVP values. That is, your CCR
record should have

   'Destination-Host' = [DH],

in this case.

>               [{diameter_gen_base_rfc4006_cc,encode_avps,2,
>                    [{file,"diameter_gen_base_rfc4006_cc.erl"},{line,47}]},
>
> {diameter_codec,e,2,[{file,"diameter_codec.erl"},{line,112}]},
>                {diameter_codec,encode,2,
>                    [{file,"diameter_codec.erl"},{line,63}]},
>                {diameter_traffic,encode,3,
>                    [{file,"diameter_traffic.erl"},{line,1437}]},
>                {diameter_traffic,send_R,6,
>                    [{file,"diameter_traffic.erl"},{line,1276}]},
>                {diameter_traffic,'-send_request/4-fun-0-',4,
>                    [{file,"diameter_traffic.erl"},{line,1050}]}]}}
>     who: <0.180.0>
>     what: {diameter_codec,encode,
>               [diameter_gen_base_rfc4006_cc,
>                {diameter_packet,
>                    {diameter_header,1,undefined,undefined,undefined,
>                        1330492780,1330492780,undefined,undefined,undefined,
>                        undefined},
>                    undefined,
>                    {diameter_base_rfc4006_cc_CCR,
>
> ["client",";","1425429748",";","2",";",""],
>                        "client.example.com","example.com","example.com",4,
>
> "Test",1,0,"server.example.com","Me",[],[],[],[],[],[],
>                        [],[],[],[],[],[],[],[],[],[],[],[]},
>                    undefined,[],undefined}]}
>
> My understanding is that the client callback prepare_request sets the
> "Destination-Host" (retrievd via the CER/A done at earilier stage) in the
> CCR message. So I should set it right. But seems I still misunderstand
> something. Does the error information "repeated_avp_excessive_arity" mean "
> 0-1 Zero or one instance of the AVP MAY be present in the message. It is

Yes, exactly. In your case your DH is being interpreted as list of
Destination-Host values, and "excessive arity" is a result of that
list having length greater than 1.

/Anders, Erlang/OTP


> considered an error if there is more than one instance of the AVP" according
> to rfc4006 spec? The erlang error message is not that straightforward,
> really confusing newbies:).
>
> Do you have any hints? (I hope I could provide some  ramp up steps for other
> people to learn with erlang diameter library after making it work^_^)
>
> Many thanks,
>
> Samuel
>
>
>
> On Thu, Mar 21, 2013 at 8:59 AM, Anders Svensson <>
> wrote:
>>
>> On Thu, Mar 21, 2013 at 2:55 AM, S X <> wrote:
>> > Hello,
>> >
>> > Sorry, I still have some problems with sending CCR/CCA messages.  I
>> > didn't
>> > quite get how to configure multiple diameter applications though it
>> > seems
>> > clear when I read the diameter protocol.
>> >
>> > Based on the sample diameter code, I made the following changes,
>> > diameter_gen_base_rfc4006_cc is the dictionary generated with
>> > rfc4006_cc.dia:
>> > $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ Client $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
>> >
>> > -define(SVC_NAME,     ?MODULE).
>> > -define(APP_ALIAS,    ?MODULE).
>> > -define(CALLBACK_MOD, client_cb).
>> > -define(DIAMETER_DICT_CCRA, diameter_gen_base_rfc4006_cc).
>> >
>> > -define(L, atom_to_list).
>> >
>> > -define(SERVICE(Name), [{'Origin-Host', ?L(Name) ++ ".example.com"},
>> >                         {'Origin-Realm', "example.com"},
>> >                         {'Vendor-Id', 0},
>> >                         {'Product-Name', "Client"},
>> >                         {'Auth-Application-Id',
>> > [?DIAMETER_APP_ID_COMMON]},
>> >                         {application, [{alias, ?APP_ALIAS},
>> >                                        {dictionary,
>> > ?DIAMETER_DICT_CCRA},
>> >                                        {module, ?CALLBACK_MOD}]}]).
>> >
>> >
>> >
>> > $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ Server $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
>> >
>> > -define(DIAMETER_DICT_CCRA, diameter_gen_base_rfc4006_cc).
>> >
>> > init(State) ->
>> >     SvcName = ?MODULE,
>> >     SvcOpts = [{'Origin-Host', atom_to_list(SvcName) ++ ".example.com"},
>> >                 {'Origin-Realm', "example.com"},
>> >                 {'Vendor-Id', 193},
>> >                 {'Product-Name', "Server"},
>> >                 {'Auth-Application-Id', [?DIAMETER_APP_ID_COMMON]},
>> >                 {application, [{alias, ?MODULE},
>> >                                {dictionary, ?DIAMETER_DICT_CCRA},
>> >                                {module, server_cb}]}],
>> >     TransportOpts = [{transport_module, diameter_tcp},
>> >                         {transport_config, [{reuseaddr, true},
>> >                         {ip, {127,0,0,1}}, {port, 3868}]}],
>> >     diameter:start(),
>> >     diameter:start_service(SvcName, SvcOpts),
>> >     diameter:add_transport(SvcName, {listen, TransportOpts}),
>> >     erlang:display("Set up diameter server completed!"),
>> >     {ok, State}.
>> >
>> >
>> >
>> > I changed the callbacks client_cb and server_cb to handle CCR/CCA
>> > messages.
>> >
>> >
>> > However, I got the following errors "app_not_configured". It seems the
>> > configuration for applications is incorrect. How should I configure the
>> > service properly? My understanding is I want to reuse CER/CEA as default
>> > authorization application, but the erlang diameter doesn't explain how
>> > to do
>> > it. Or my understanding is incorrect at all.
>>
>> The problem is a mismatch between the application and capabilities
>> configuration in your SvcOpts:  the 'Auth-Application-Id' tuple
>> specifies the Application Id's that are advertised in the outgoing
>> CER/CEA (that diameter itself sends) while 'applications' specifies
>> corresponding dictionary modules. In your case, advertising the common
>> application (0) during capabilities exchange but backing it up with a
>> dictionary that implement CC (4) is what causes things to go south.
>>
>> What you want is something like this:
>>
>>   {'Auth-Application-Id', [0,4]},
>>   {application, [{alias, cc},
>>                      {dictionary, diameter_gen_base_rfc4006},
>>                      {module, [server_cb, cc]}],
>>   {application, [{alias, base},
>>                      {dictionary, diameter_gen_base_rfc6733},
>>                      {module, [server_cb, base]}]}
>>
>> That is, advertise both application with the Auth-Application-Id
>> config and configure corresponding dictionaries with 'application'
>> config. You might prefer two different callback modules (instead of an
>> extra argument) but the point is to match your advertised capabilities
>> with your configured dictionaries.
>>
>> On a side note, you shouldn't use a diameter prefix on your own
>> dictionaries, so as not to collide with something diameter does in the
>> future.
>>
>> /Anders, Erlang/OTP
>>
>> >
>> > =ERROR REPORT==== 20-Mar-2013::21:40:50 ===
>> > ** Generic server <0.3841.0> terminating
>> > ** Last message in was {diameter,
>> >                            {recv,
>> >
>> > <<1,0,0,124,128,0,1,1,0,0,0,0,101,222,1,72,
>> >
>> > 101,222,1,72,0,0,1,8,64,0,0,26,99,108,105,
>> >
>> > 101,110,116,46,101,120,97,109,112,108,101,
>> >
>> > 46,99,111,109,0,0,0,0,1,40,64,0,0,19,101,
>> >
>> > 120,97,109,112,108,101,46,99,111,109,0,0,0,
>> >
>> > 1,1,64,0,0,14,0,1,127,0,0,1,0,0,0,0,1,10,64,
>> >
>> > 0,0,12,0,0,0,193,0,0,1,13,0,0,0,14,67,108,
>> >
>> > 105,101,110,116,0,0,0,0,1,2,64,0,0,12,0,0,0,
>> >                                  0>>}}
>> > ** When Server state == {state,recv_CER,accept,<0.3840.0>,<0.3842.0>,
>> >                             diameter_gen_base_rfc3588,
>> >                             {diameter_service,<0.50.0>,
>> >                                 {diameter_caps,"server.example.com",
>> >                                     "example.com",
>> >                                     [{127,0,0,1}],
>> >                                     193,"Server",[],[],
>> >                                     [0],
>> >                                     [],[],[],[],[]},
>> >                                 [{diameter_app,server,
>> >                                      diameter_gen_base_rfc4006_cc,
>> >                                      [server_cb],
>> >                                      server,4,false,
>> >                                      [{answer_errors,report},
>> >                                       {request_errors,answer_3xxx}]}]},
>> >                             false,exit}
>> > ** Reason for termination ==
>> > ** {{badmatch,{error,{app_not_configured,0}}},
>> >     [{diameter_peer_fsm,recv_CER,2,
>> >
>> > [{file,"src/diameter_peer_fsm.erl"},{line,849}]},
>> >      {diameter_peer_fsm,build_answer,3,
>> >
>> > [{file,"src/diameter_peer_fsm.erl"},{line,680}]},
>> >      {diameter_peer_fsm,send_answer,3,
>> >
>> > [{file,"src/diameter_peer_fsm.erl"},{line,647}]},
>> >      {diameter_peer_fsm,handle_info,2,
>> >
>> > [{file,"src/diameter_peer_fsm.erl"},{line,292}]},
>> >      {gen_server,handle_msg,5,[{file,"gen_server.erl"},{line,607}]},
>> >      {proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,239}]}]}
>> >
>> >
>> > Could you give me some hints on this issue? The erlang debugger is not
>> > easy
>> > to use and call stack information is hard to read (when I show the trace
>> > window, all the buttons for step/next/continue become invisible). The
>> > diameter guidance explains the concept but no clear steps about
>> > configuration.
>> >
>> >
>> > Many thanks!
>> >
>> > Samuel
>> >
>> >
>> >
>> > On Tue, Mar 12, 2013 at 12:10 PM, S X <> wrote:
>> >>
>> >> Hello, Anders & Andre,
>> >>
>> >> Thanks a lot for your quick responses and suggestions, which help me
>> >> start
>> >> to exploring Erlang world ^_^
>> >>
>> >> I was able to generate based on the file rfc4006_cc.dia under the
>> >> diameter/examples/dict folders. And understand a bit why and how Erlang
>> >> diameter protocol dictionaries are organized and maintained.
>> >>
>> >> Many thanks and talk to you later!
>> >>
>> >> Samuel
>> >>
>> >>
>> >> On Tue, Mar 12, 2013 at 7:44 AM, Anders Svensson <>
>> >> wrote:
>> >>>
>> >>> Btw, there's an RFC 4006 dictionary (and a few more) under
>> >>> diameter/examples/dict in the repo.
>> >>>
>> >>> /Anders, Erlang/OTP
>> >>>
>> >>> On Tue, Mar 12, 2013 at 10:32 AM, André Graf <>
>> >>> wrote:
>> >>> > Hello S(?)
>> >>> >
>> >>> > You have to come up with your own .dia file if the message types are
>> >>> > not covered in the .dia files provided by Erlang. Your own .dia file
>> >>> > will typically include the  '@inherits diameter_gen_base_rfc3588'
>> >>> > clause which imports the basic avp's from rfc3588. You then have to
>> >>> > provide the missing avp's for your CCR/CCA message types, and also
>> >>> > define these messages. Thanks to the format of a .dia file it is
>> >>> > pretty much copy-pasting from the rfc4006. Once your .dia file is
>> >>> > ready, you use diameterc to generate the .erl and .hrl file.
>> >>> >
>> >>> > Hope that helped!
>> >>> >
>> >>> > BR/André
>> >>> >
>> >>> >
>> >>> >
>> >>> > On 12 March 2013 04:58, S X <> wrote:
>> >>> >> Hello,
>> >>> >>
>> >>> >> I am new to Erlang and Diameter protocol. Wish someone could
>> >>> >> provide
>> >>> >> some
>> >>> >> suggestions on how to utilize the diameter library properly in
>> >>> >> Erlang.
>> >>> >>
>> >>> >> For example, I want to send/receive some Gx messages, like CCR
>> >>> >> (Credit
>> >>> >> Control Request), CCA(Credit Control Answer messages. But I notice
>> >>> >> that
>> >>> >> there are some predefined messages in erlang diameter library. As
>> >>> >> my
>> >>> >> understanding, should use the utility diameterc to generate erlang
>> >>> >> header/source files based on dia files. There are few dia files
>> >>> >> under
>> >>> >> otp/lib/diameter/src/dict folder, like acct_rfc6733.dia,
>> >>> >> base_rfc3588.dia,
>> >>> >> relay.dia, base_accounting.dia,  base_rfc6733.dia. Those files
>> >>> >> don't
>> >>> >> have
>> >>> >> the definitions for Gx.
>> >>> >>
>> >>> >> How should I generate or where can I obtain dia files which have
>> >>> >> support for
>> >>> >> CCR/CCA message format? Are the dia files proprietary or
>> >>> >> manufacturer
>> >>> >> specific? Can I generate with the 3GPP spec? What are the proper
>> >>> >> steps?
>> >>> >>
>> >>> >> Thanks a lot!
>> >>> >>
>> >>> >> S
>> >>> >>
>> >>> >>
>> >>> >> _______________________________________________
>> >>> >> erlang-questions mailing list
>> >>> >> 
>> >>> >> http://erlang.org/mailman/listinfo/erlang-questions
>> >>> >>
>> >>> > _______________________________________________
>> >>> > erlang-questions mailing list
>> >>> > 
>> >>> > http://erlang.org/mailman/listinfo/erlang-questions
>> >>
>> >>
>> >
>
>



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