# &adminguide;

## Overview

This module implements SIP authentication and authorization with DIAMETER server, namely DIameter Server Client (DISC).

NOTE: diameter support was developed for DISC (DIameter Server Client project at http://developer.berlios.de/projects/disc/). This project seems to be no longer maintained and DIAMETER specifications were updated in the meantime. Thus, the module is obsolete and needs rework to be usable with opendiameter or other DIAMETER servers.

The digest authentication mechanism is presented in next figure.

### Digest Authentication

    ...
    	a) First phase of Digest Authentication for SIP:

         +----+ SIP INVITE   +=====+  DIAMETER      +------+       +------+
         |    | no Auth hdr  #/////#  AA-Request    |      |       |      |
         |    |---------1--->#/////#-------2------->|      |---2-->|      |
         |UAC |              #UAS//#                |DClnt |       |DSrv  |
         |    |<-----4-------#(SER)#<------3--------|(DISC)|<--3---|(DISC)|
         |    |     401      #/////#  DIAMETER      |      |       |      |
         +----+ Unauthorized +=====+  AA-Answer     +------+       +------+
                                      Result-Code=4001

    	b) Second phase of Digest Authentication for SIP:

         +----+ SIP INVITE   +=====+  DIAMETER     +------+       +----+
         |    | Auth hdr     #/////#  AA-Request   |      |       |    |
         |    |--------1---->#/////#-------2------>|      |---2-->|    |
         |UAC |              #UAS//#               |DClnt |       |DSrv|
         |    |<-------4-----#(SER)#<------3-------|      |<--3---|    |
         |    |      200 OK  #/////#  DIAMETER     |      |       |    |
         +----+              +=====+  AA-Answer    +------+       +----+
                                      Result-Code=2001

    ...

## Dependencies

### &kamailio; Modules

The following modules must be loaded before this module:

- sl - used to send stateless replies.

### External Libraries or Applications

The following libraries or applications must be installed before running &kamailio; with this module loaded:

- None.

## Parameters

### `diameter_client_host` (string)

Hostname of the machine where the DIAMETER Client is running.

Default value is localhost.

#### Set `diameter_client_host` parameter

    ...
    modparam("auth_diameter", "diameter_client_host", "10.10.10.10")
    ...

### `diameter_client_port` (int)

Port number where the DIAMETER Client is listening.

Default value is 3000.

#### Set `diameter_client_port` parameter

    ...
    modparam("auth_diameter", "diameter_client_port", 3000)
    ...

### `use_domain` (int)

Specifies whether the domain name part of URI is used when checking the user's privileges.

Default value is 0 (0==false and 1==true ).

#### Set `use_domain` parameter

    ...
    modparam("auth_diameter", "use_domain", 1)
    ...

## Functions

### `diameter_www_authorize(realm)`

SIP Server checks for authorization having a DIAMETER server in backend. If no credentials are provided inside the SIP request then a challenge is sent back to UAC. If the credentials don't match the ones computed by DISC then 403 Forbidden is sent back.

Negative codes may be interpreted as follows:

- -5 (generic error) - some generic error occurred and no reply was sent out;

- -3 (stale nonce) - stale nonce;

Meaning of the parameters is as follows:

- realm - the realm to be use for authentication and authorization. The string may contain pseudo variables.

This function can be used from REQUEST_ROUTE.

#### `diameter_www_authorize` usage

    ...
    if(!diameter_www_authorize("siphub.net"))
    { /* user is not authorized */
    	exit;
    };
    ...

### `diameter_proxy_authorize(realm)`

SIP Proxy checks for authorization having a DIAMETER server in backend. If no credentials are provided inside the SIP request then a challenge is sent back to UAC. If the credentials don't match the ones computed by DISC then 403 Forbidden is sent back. For more about the negative return codes, see the above function.

Meaning of the parameters is as follows:

- realm - the realm to be use for authentication and authorization. The string may contain pseudo variables.

This function can be used from REQUEST_ROUTE.

#### `diameter_proxy_authorize` usage

    ...
    if(!diameter_proxy_authorize("siphub.net"))
    { /* user is not authorized */
    	exit;
    };
    ...

### `diameter_is_user_in(who, group)`

The method performs group membership checking with DISC.

Meaning of the parameters is as follows:

- who - what header to be used to get the SIP URI that is wanted to be checked being member in a certain group. It can be: Request-URI, From, To or Credentials.

- group - the group name where to check if the user is part of.

This function can be used from REQUEST_ROUTE.

#### `diameter_is_user_in` usage

    ...
    if(!diameter_is_user_in("From", "voicemail"))
    { /* user is not authorized */
    	exit;
    };
    ...

## Installation and Running

Notes about installation and running.