# &adminguide;

## Overview

This module contains all authentication related functions for an IMS environment. The module does not depend on the base Kamailio auth modules as other auth modules do. Instead ims_auth is dependent on the CDP (C Diameter Peer) modules for communicating with HSS as specified in 3GPP specs.

## Dependencies

### &kamailio; Modules

The Following modules must be loaded before this module:

- TM - Transaction Manager

- CDP - C Diameter Peer (for av_mode=0)

- CDP_AVP - CDP AVP Applications (for av_mode=0)

- GCRYPT - GNU Crypto functions (for av_mode=1)

### External Libraries or Applications

This module requires the internal IMS library.

## Parameters

### `name` (string)

This is the name of the SCSCF as identified in communication with the HSS (Server-Name AVP of MAR).

Default value is 'sip:scscf.ims.smilecoms.com:6060'.

#### `name` parameter usage

    ...
    modparam("ims_auth", "name", "sip:scscf3.ims.smilecoms.com:6060")
    ...

### `auth_data_hash_size` (integer)

This is the size of the hash table used to store auth vectors (AV). Default value is fine for most people. Use the parameter if you really need to change it.

Default value is 1024.

#### `auth_data_hash_size` parameter usage

    ...
    modparam("ims_auth", "auth_data_hash_size", 1024)
    ...

### `auth_vector_timeout` (integer)

This is the time, in seconds, that a SENTauth vector is valid for. If there is no response ...

Default value is 60.

#### `auth_vector_timeout` parameter usage

    ...
    modparam("ims_auth", "auth_vector_timeout", "domain")
    ...

### `auth_data_timeout` (int)

Time, in seconds, a used auth vector is valid for.

Default value is 60.

#### `password_column` parameter usage

    ...
    modparam("ims_auth", "auth_data_timeout", 60)
    ...

### `av_request_at_once` (integer)

How many auth vectors to request in MAR.

Default value is 1

#### `av_request_at_once` parameter usage

    ...
    modparam("ims_auth", "av_request_at_once", 1)
    ...

### `av_request_at_sync` (integer)

How many auth vectors to request at sync. Default value is 1.

#### `av_request_at_sync` parameter usage

    ...
    modparam("ims_auth", "av_request_at_sync", 1)
    ...

### `registration_default_algorithm` (string)

The default authentication algorithm to use for registration if one is not specified.

Options are:

- AKAV1-MD5

- AKAV2-MD5

- MD5

- HSS-Selected - HSS will decide on auth algorithm

Default value is AKAv1-MD5.

#### `registration_default_algorithm` parameter usage

    ...
    modparam("ims_auth", "registration_default_algorithm", "HSS-Selected")
    ...

### `registration_qop` (string)

The QOP options to put in the authorisation challenges.

Default value of this parameter is auth,auth-int.

#### `registration_qop` parameter usage

    ...
    modparam("ims_auth", "registration_qop", "auth-int")
    ...

### `cxdx_forced_peer` (string)

FQDN of Diameter Peer (HSS) to use for communication (MAR). If you use this, the routing defined in your diameter xml configuration file (CDP) will be ignored and as a result you will lose the benefits of load balancing and failover.

Default value is .

#### `cxdx_forced_peer` parameter usage

    ...
    modparam("ims_auth", "cxdx_forced_peer", "hss.ims.smilecoms.com")
    ...

### `cxdx_dest_realm` (string)

Destination realm to be used in Diameter messages to HSS

Default value is ims.smilecoms.com.

#### `cxdx_dest_realm` parameter usage

    ...
    modparam("ims_auth", "cxdx_dest_realm", "ims.smilecoms.com")
    ...

### `cxdx_dest_host` (string)

Destination Host to be used in Diameter-MAR messages to HSS

Default value is (not set).

#### `cxdx_dest_host` parameter usage

    ...
    modparam("ims_auth", "cxdx_dest_host", "hss.ims.ng-voice.com")
    ...

### `max_nonce_reuse` (integer)

Defines, how many times a nonce can be reused (provided nc is incremented)

Default value is 0 (don't allow reuse).

#### `max_nonce_reuse` parameter usage

    ...
    modparam("ims_auth", "max_nonce_reuse", 1)
    ...

### `add_authinfo_hdr` (integer)

Should an Authentication-Info header be added on 200 OK responses?

Default value is 1 (add Authentication-Info header).

#### `add_authinfo_hdr` parameter usage

    ...
    modparam("ims_auth", "add_authinfo_hdr", 0)
    ...

### `ignore_failed_auth` (integer)

Ignore invalid passwords (only IMPI/IMPU is checked).

It should be used only for testing, e.g. load balancing with SIPP where we don't want to worry about auth.

Default value is 0 (don't ignore the failed authentication).

#### `ignore_failed_auth` parameter usage

    ...
    modparam("ims_auth", "ignore_failed_auth", 1)
    ...

### `av_check_only_impu` (integer)

When storing the authentication vectors for an account, use either IMPI/IMPU (=0, default) or IMPU (=1).

In case the IMPI is different from the IMPU, this option needs to be enabled to allow registration from classic "SIP-clients", such as Snom phones and others, as they do not send an authentication username in the first REGISTER.

Default value is 0 (store authentication vectors based on IMPI/IMPU).

#### `av_check_only_impu` parameter usage

    ...
    modparam("ims_auth", "av_check_only_impu", 1)
    ...

### `av_mode` (integer)

Control how authentication vector is generated: 0 - get it from HSS via DIAMETER; 1 - generate it locally. Default is 0.

#### `av_mode` parameter usage

    ...
    modparam("ims_auth", "av_mode", 1)
    ...

## Functions

### `ims_www_authorize(realm, table)`

The function verifies credentials according to RFC2617. If the credentials are verified successfully then the function will succeed and mark the credentials as authorized (marked credentials can be later used by some other functions). If the function was unable to verify the credentials for some reason then it will fail and the script should call `www_challenge` which will challenge the user again.

Negative codes may be interpreted as follows:

- -1 (generic error) - some generic error occurred and no reply was sent out;

- -2 (invalid password) - valid user, but wrong password;

- -3 (invalid user) - authentication user does not exist.

Meaning of the parameters is as follows:

- realm - Realm is a opaque string that the user agent should present to the user so he can decide what username and password to use. Usually this is domain of the host the server is running on.

  It must not be empty string . In case of REGISTER requests To header field domain (e.g., variable $td) can be used (because this header field represents the user being registered), for all other messages From header field domain can be used (e.g., variable $fd).

  The string may contain pseudo variables.

- table - Table to be used to lookup usernames and passwords (usually subscribers table).

This function can be used from REQUEST_ROUTE.

#### `www_authorize` usage

    ...
    if (!www_authorize("kamailio.org", "subscriber")) {
    	www_challenge(""REG_MAR_REPLY"", "kamailio.org", "1");
    };
    ...

### `ims_www_authenticate(realm)`

It is the same function as www_authenticate(realm, table). This name is kept for backward compatibility, since it was named this way first time by it actually does user authentication.

### `ims_www_challenge(route_block, realm)`

Name alias: proxy_authorize(realm, table)

The function verifies credentials according to RFC2617. If the credentials are verified successfully then the function will succeed and mark the credentials as authorized (marked credentials can be later used by some other functions). If the function was unable to verify the credentials for some reason then it will fail and the script should call `proxy_challenge` which will challenge the user again.

Negative return codes have the same meaning as for www_authenticate().

Meaning of the parameters is as follows:

- Route block to resume after async MAR Diameter reply.

- realm - Realm is a opaque string that the user agent should present to the user so he can decide what username and password to use. Usually this is domain of the host the server is running on.

  It must not be empty string . Apart of a static string, typical value is From header field domain (e.g., variable $fd).

  If an empty string is used then the server will generate it from the request. From header field domain will be used as realm.

  The string may contain pseudo variables.

This function can be used from REQUEST_ROUTE.

#### ims_www_challenge usage

    ...
    if (!proxy_authorize("$fd", "subscriber)) {
    	proxy_challenge(""REG_MAR_REPLY","$fd");  # Realm will be autogenerated
    };
    ...
                ...
    route[REG_MAR_REPLY]
    {
         #this is async so to know status we have to check the reply avp
         xlog("L_DBG","maa_return code is $avp(s:maa_return_code)\n");

         switch ($avp(s:maa_return_code)){
                 case 1: #success
                         xlog("L_DBG", "MAR success - 401/407 response sent from module\n");
                         break;
                 case -1: #failure
                         xlog("L_ERR", "MAR failure - error response sent from module\n");
                         break;
                 case -2: #error
                         xlog("L_ERR", "MAR error - sending error response now\n");
                         t_reply("500", "MAR failed");
                         break;
                 default:
                         xlog("L_ERR", "Unknown return code from MAR, value is [$avp(s:uaa_return_code)]\n");
                         t_reply("500", "Unknown response code from MAR");
                         break;
         }
         exit;
    }

### `ims_www_challenge(route_block, realm, algorithm)`

Same as 4.3 except here there is the additional option to specify the authorisation algorithm

- algorithm - The algorithm to be used when challenging the client. Can be AKAv1-MD5, AKAv2-MD5, MD5, or HSS-Selected. If left as an empty string, the default algorithm will be chosen according to the parameter registration_default_algorithm (see section 3.7)

This function can be used from REQUEST_ROUTE.

#### ims_www_challenge usage

    ...
     if (!ims_www_authenticate(NETWORKNAME)) {
                    #user has not been authenticated. Lets send a challenge via 401 Unauthorized
                    if ($? == -2) {
                            t_reply("403", "Authentication Failed");
                            exit;
                    } else if ($? == -3) {
                            t_reply("400", "Bad Request");
                            exit;
                    } else if ($? == -9) {
                            xlog("L_DBG", "Authentication re-sync requested\n");
                            ims_www_resync_auth("REG_RESYNC_REPLY", "$td");
                            exit;
                    } else {
                            xlog("L_DBG","About to challenge! auth_ims\n");
                            ims_www_challenge("REG_MAR_REPLY", "$td", "MD5");
                            exit;
                    }
            }

### `ims_proxy_challenge(route_block, realm, table)`

Name alias: proxy_authorize(realm, table)

The function verifies credentials according to RFC2617. If the credentials are verified successfully then the function will succeed and mark the credentials as authorized (marked credentials can be later used by some other functions). If the function was unable to verify the credentials for some reason then it will fail and the script should call `proxy_challenge` which will challenge the user again.

Negative return codes have the same meaning as for www_authenticate().

Meaning of the parameters is as follows:

- Route block to resume after async MAR Diameter reply.

- realm - Realm is a opaque string that the user agent should present to the user so he can decide what username and password to use. Usually this is domain of the host the server is running on.

  It must not be empty string . Apart of a static string, typical value is From header field domain (e.g., variable $fd).

  If an empty string is used then the server will generate it from the request. From header field domain will be used as realm.

  The string may contain pseudo variables.

- table - Table to be used to lookup usernames and passwords (usually subscribers table).

This function can be used from REQUEST_ROUTE.

#### proxy_authorize usage

    ...
    if (!proxy_authorize("$fd", "subscriber)) {
    	proxy_challenge("REG_MAR_REPLY","$fd", "1");  # Realm will be autogenerated
    };
    ...
    route[REG_MAR_REPLY]
    {
         #this is async so to know status we have to check the reply avp
         xlog("L_DBG","maa_return code is $avp(s:maa_return_code)\n");

         switch ($avp(s:maa_return_code)){
                 case 1: #success
                         xlog("L_DBG", "MAR success - 401/407 response sent from module\n");
                         break;
                 case -1: #failure
                         xlog("L_ERR", "MAR failure - error response sent from module\n");
                         break;
                 case -2: #error
                         xlog("L_ERR", "MAR error - sending error response now\n");
                         t_reply("500", "MAR failed");
                         break;
                 default:
                         xlog("L_ERR", "Unknown return code from MAR, value is [$avp(s:uaa_return_code)]\n");
                         t_reply("500", "Unknown response code from MAR");
                         break;
         }
         exit;
    }
    ...

### `ims_proxy_authenticate(realm, table)`

It is same function as proxy_authenticate(realm, table). This name is kept for backward compatibility, since it was named this way first time but it actually does user authentication.

### `ims_auth_data_set(key, op, op_c, amf)`

Set the key, op, op_c and amf to be used for AKAv1-MD5 authentication when av_mode parameter is set to 1 (authentication vector generated locally). It has to be used before the function for doing authentication.

The parameters can be variables, their values can be retrieved from a backend (e.g., from database using sqlops module or from a REST API server using http_client module).

- key - the SIM key

  op - the operator key (can be empty if op_c is set)

  op_c - the derived operator key (can be empty if op is set)

  amf - the amf code

This function can be used from REQUEST_ROUTE.

#### ims_auth_data_set

    ...
    ims_auth_data_set("...", "...", "...", "...");
    ...

### `ims_auth_data_reset()`

Reset the authentication attributes when av_mode parameter is set to 1.

This function can be used from REQUEST_ROUTE.

#### ims_auth_data_reset

    ...
    ims_auth_data_reset();
    ...

## Statistics

### MAR Timeouts (mar_timeouts)

The number of timeouts on sending a MAR. i.e. no response to MAR.

### Average MAR Response Time (mar_avg_response_time)

The average response time in milliseconds for MAR-MAA transaction.