erGW-AAA - AAA component for the erGW project

This is a companion project for the erGW project to provide an abstract
AAA (Authentication, Authorization and Accounting) interface for protocols
based on erGW.

Supported backend providers are:

• a local dummy (mock)
• RADIUS

Work on progress:

• DIAMETER
• flexible configuration
• the dropped attribute_map feature might be readded

In the future possible other providers are:

• LDAP (Authentication and Authorization only)

TERMINATION CAUSE MAPPING

When ergw needs to terminate an AAA session, the termination reasons to be included in those messages (e.g. CCR-T or ACR stop in diameter and Accounting-Request stop in Radius) are provided by the ergw to the ergw_aaa in the session data in the format of atoms.
Each AAA handler can have a mapping configured to map these to termination causes of the corresponding protocol/interface.
See RFCs: RFC2866, RFC3588.
An example of this mapping:

%% DIAMETER config example
% ...
{handlers, [
    % ...
    {ergw_aaa_ro, [
        {function, 'ergw-pgw-epc-ro'},
        {'Destination-Realm', <<"test.apn.net">>},
        {termination_cause_mapping, [
            {normal, 1},           
            {administrative, 4}, 
            {link_broken, 5},      
            {upf_failure, 5},      
            {remote_failure, 1},   
            {cp_inactivity_timeout, 1},
            {up_inactivity_timeout, 1},
            {peer_restart, 1},
            {'ASR', 1},
            {error, 1},
            {timeout, 1},
            {conn_error, 1},
            {rate_limit, 1},
            {ocs_hold_end, 1},
            {peer_reject, 1}
        ]}
    ]}
    % ...
]},
%...

% RADIUS config example
% ...
{ergw_aaa_radius, [
    {server, {{192,168,255,1}, 1813, <<"radproxy">>}},
        {termination_cause_mapping, [
            {normal, 1},
            {administrative, 6},
            {link_broken, 2},
            {upf_failure, 9},
            {remote_failure, 9},
            {cp_inactivity_timeout, 4},
            {up_inactivity_timeout, 4},
            {peer_restart, 7},
            {'ASR', 6},
            {error, 9},
            {timeout, 4},
            {conn_error, 10},
            {rate_limit, 10},
            {ocs_hold_end, 10},
            {peer_reject, 10}
        ]}
]}
% ...

BUILDING

Using rebar3:

# rebar3 compile

CONFIGURATION

For all releases in the 3.x stream, the configuration syntax might change at
any point and might not be backward compatible.

Example of possible config.

 {ergw_aaa,
  [{functions,
    [{'ergw-pgw-epc',
      [{handler, ergw_aaa_diameter},
       {'Origin-Host', <<"ergw-pgw.dia.example.net">>},
       {'Origin-Realm', <<"dia.example.net">>},
       {transports, [
           [{connect_to, <<"aaa://srv1.dia.example.net;transport=sctp">>},
            {recbuf, 32768}]
        ]},
      ]}
    ]},
   {handlers,
    [{ergw_aaa_static,
        [{'NAS-Identifier',          <<"NAS-Identifier">>},
         {'Acct-Interim-Interval',   600},
         {'Framed-Protocol',         'PPP'},
         {'Service-Type',            'Framed-User'},
         {'Node-Id',                 <<"PGW-001">>},
         {'Charging-Rule-Base-Name', <<"m2m0001">>},
         {rules, #{'Default' =>
                       #{'Rating-Group' => [3000],
                         'Flow-Information' =>
                             [#{'Flow-Description' => [<<"permit out ip from any to assigned">>],
                                'Flow-Direction'   => [1]    %% DownLink
                               },
                              #{'Flow-Description' => [<<"permit out ip from any to assigned">>],
                                'Flow-Direction'   => [2]    %% UpLink
                               }],
                         'Metering-Method'  => [1],
                         'Precedence' => [100]
                        }
                  }
         }
        ]},
     {ergw_aaa_radius, [
        {server, {{127,0,0,1}, 1812, <<"secret">>}},
        {termination_cause_mapping, [
            {normal, 1},
            {administrative, 6},
            {link_broken, 2},
            {upf_failure, 9},
            {remote_failure, 9},
            {cp_inactivity_timeout, 4},
            {up_inactivity_timeout, 4},
            {peer_restart, 7},
            {'ASR', 6},
            {error, 9},
            {timeout, 4},
            {conn_error, 10},
            {rate_limit, 10},
            {ocs_hold_end, 10},
            {peer_reject, 10}
        ]}
     ]},
     {ergw_aaa_rf, [{transport, 'ergw-pgw-epc'}]},
     {ergw_aaa_ro, [
        {transport, 'ergw-pgw-epc'},
        {termination_cause_mapping, [
            {normal, 1},           
            {administrative, 4}, 
            {link_broken, 5},      
            {upf_failure, 5},      
            {remote_failure, 1},   
            {cp_inactivity_timeout, 1},  
            {up_inactivity_timeout, 1},
            {peer_restart, 1},
            {'ASR', 1},
            {error, 1},
            {timeout, 1},
            {conn_error, 1},
            {rate_limit, 1},
            {ocs_hold_end, 1},
            {peer_reject, 1}
        ]}
     ]}
    ]},
   {services,
    [{'Default',     [{handler, 'ergw_aaa_static'}]},
     {'RADIUS-Auth', [{handler, 'ergw_aaa_radius'},
                      {server, {{127,1,0,1}, 1812, <<"secret">>}}]},
     {'RADIUS-Acct', [{handler, 'ergw_aaa_radius'},
                      {server, {{127,2,0,1}, 1813, <<"secret">>}}]},
     {'Rf',          [{handler, 'ergw_aaa_rf'}]},
     {'Gx',          [{handler, 'ergw_aaa_gx'}]}
     {'Gy',          [{handler, 'ergw_aaa_ro'}]}
    ]},
   {apps,
    [ {'Origin-Host', <<"local.host">>},
      {procedures,
        [{default,
          [{session, ['Default']},
           {procedures, [{authenticate, ['RADIUS-Auth']},
                         {authorize,    ['RADIUS-Auth']},
                         {start,     ['RADIUS-Acct', 'Rf']},
                         {interim,   ['RADIUS-Acct', 'Rf']},
                         {stop,      ['RADIUS-Acct', 'Rf']},
                         {{gx, 'CCR-Initial'},   ['Gx']},
                         {{gx, 'CCR-Update'},    ['Gx']},
                         {{gx, 'CCR-Terminate'}, ['Gx']},
                         {{gy, 'CCR-Initial'},   ['Gy']},
                         {{gy, 'CCR-Update'},    ['Gy']},
                         {{gy, 'CCR-Terminate'}, ['Gy']}]}
          ]}
        ]}
    ]}
  ]},