<!-- Auth_db Module User's Guide -->

<chapter>
    <chapterinfo>
	<revhistory>
	    <revision>
		<revnumber>$Revision$</revnumber>
		<date>$Date$</date>
	    </revision>
	</revhistory>
    </chapterinfo>
    <title>User's Guide</title>
    
    <section>
	<title>Overview</title>
	<para>
	    This module contains all authentication related functions that need the access to the
	    database. This module should be used together with auth module, it cannot be used
	    independently because it depends on the module. Select this module if you want to use
	    database to store authentication information like subscriber usernames and passwords. If
	    you want to use radius authentication, then use auth_radius instead.
	</para>
    </section>
    <section>
	<title>Dependencies</title>
	<para>
	    The module depends on the following modules (in the other words the listed modules
	    must be loaded before this module):
	    <itemizedlist>
		<listitem>
		    <para><emphasis>auth</emphasis> -- Generic authentication functions</para>
		</listitem>
		<listitem>
		    <para><emphasis>database</emphasis> -- Any database module (currently mysql,
		    postgres, dbtext)</para>
		</listitem>
	    </itemizedlist>
	</para>
    </section>
    <section>
	<title>Exported Parameters</title>
	<section>
	    <title><varname>db_url</varname> (string)</title>
	    <para>
		This is URL of the database to be used. Value of the parameter depends on the
		database module used. For example for mysql and postgres modules this is something
		like sql://username:password@host:port/database. For dbtext module (which stores
		data in plaintex files) it is directory in which the database resides.
	    </para>
	    <para>
		Default value is <quote>sql://serro:47serro11@localhost/ser</quote>.
	    </para>
	    <example>
		<title><varname>db_url</varname> parameter usage</title>
		<programlisting format="linespecific">
modparam("auth_db", "db_url", "sql://foo:bar@foobar.org/ser")
</programlisting>
	    </example>
	</section>
	<section>
	    <title><varname>user_column</varname> (string)</title>
	    <para>
		This is the name of the column holding usernames. Default value is fine for most
		people. Use the parameter if you really need to change it.
	    </para>
	    <para>
		Default value is <quote>username</quote>.
	    </para>
	    <example>
		<title><varname>user_column</varname> usage</title>
		<programlisting format="linespecific">
modparam("auth_db", "user_column", "user")
</programlisting>
	    </example>
	</section>
	<section>
	    <title><varname>domain_column</varname> (string)</title>
	    <para>
		This is the name of the column holding domains of users. Default value is fine for
		most people. Use the parameter if you really need to change it.
	    </para>
	    <para>
		Default value is <quote>domain</quote>.
	    </para>
	    <example>
		<title><varname>domain_column</varname> usage</title>
		<programlisting format="linespecific">
modparam("auth_db", "domain_column", "domain")
</programlisting>
	    </example>
	</section>
	<section>
	    <title><varname>password_column</varname> (string)</title>
	    <para>
		This is the name of the column holding passwords. Passwords can be either stored as
		plain text or pre-calculated HA1 strings. HA1 strings are MD5 hashes of username,
		password, and realm. HA1 strings are more safe because the server doesn't need to
		know plaintext passwords and they cannot be obtained from HA1 strings.
	    </para>
	    <para>
		Default value is <quote>ha1</quote>.
	    </para>
	    <example>
		<title><varname>password_column</varname> usage</title>
		<programlisting format="linespecific">
modparam("auth_db", "password_column", "password")
</programlisting>
	    </example>
	</section>
	<section>
	    <title><varname>rpid_column</varname> (string)</title>
	    <para>
		This is the name of the column holding information for the Remote-Party-ID header field. Default value is fine for most
		people. Use the parameter if you really need to change it.
	    </para>
	    <para>
		Default value is <quote>rpid</quote>.
	    </para>
	    <example>
		<title><varname>rpid_column</varname> usage</title>
		<programlisting format="linespecific">
modparam("auth_db", "rpid_column", "remote_party_id")
</programlisting>
	    </example>
	</section>
	<section>
	    <title><varname>calculate_ha1</varname> (integer)</title>
	    <para>
		This parameter tells server whether it should expect plaintext passwords in the
		database or HA1 string. If the parameter is set to 1 then the server will assume
		that the column pointed to by <varname>password_column</varname> contains plaintext
		passwords and it will calculate HA1 strings on the fly.
	    </para>
	    <para>
		If the parameter is set to 0 then the server assumes that the database contains HA1
		strings directly and will not calculate them. If username parameter of credentials
		contains also @domain (some user agents put domain in username parameter), then
		column pointed to by <varname>password_column_2</varname> parameter will be used
		instead. This column should also contain HA1 strings but they should be calculated
		including the domain in the username parameter (as opposed to
		<varname>password_column</varname> which (when containing HA1 strings) should always
		contains HA1 strings calculated without domain in username.
	    </para>
	    <para>
		This ensures that the authentication will always work when using pre-calculated HA1
		string, not depending on the presence of the domain in username.
	    </para>
	    <para>
		Default value of this parameter is 0.
	    </para>
	    <example>
		<title><varname>calculate_ha1</varname>usage</title>
		<programlisting format="linespecific">
modparam("auth_db", "calculate_ha1", 1)
</programlisting>
	    </example>
	</section>
	<section>
	    <title><varname>password_column_2</varname> (string)</title>
	    <para>
		As described in the previous section this parameter contains name of column holding
		pre-calculated HA1 string that were calculated including the domain in the
		username. This parameter is used only when <varname>calculate_ha1</varname> is set
		to 0 and user agent send a credentials containing the domain in the username.
	    </para>
	    <para>
		Default value of the parameter is ha1b.
	    </para>
	    <example>
		<title><varname>password_column_2</varname> usage</title>
		<programlisting format="linespecific">
modparam("auth_db", "password_column_2", "ha1_2")
</programlisting>
	    </example>
	</section>
	<section>
	    <title><varname>use_rpid</varname> (integer)</title>
	    <para>
		This parameter specifies  whether the server should fetch a value for the Remote-Party-ID header field from the database.
	    </para>
	    <para>
		If the parameter is set to 1 the server expects to find a value for this header in the column specified by the <varname>rpid_column</varname> parameter.
	    </para>
	    <para>
		Default value of this parameter is 0.
	    </para>
	    <example>
		<title><varname>use_rpid</varname>usage</title>
		<programlisting format="linespecific">
modparam("auth_db", "use_rpid", 1)
</programlisting>
	    </example>
	</section>
    </section>

    <section>
	<title>Exported Functions</title>
	<section>
	    <title><function moreinfo="none">www_authorize(realm, table)</function></title>
	    <para>
		The function verifies credencials according to RFC2617. If the credentials are
		verified sucessfully 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 <function moreinfo="none">www_challenge</function> which will
		challenge the user again.
	    </para>
	    <para>Meaning of the parameters is as follows:</para>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>realm</emphasis> - Realm is a opaque string that the user agent
		    should present to the user so he can decide what username and password to
		    use. Usualy this is domain of the host the server is running on.
		    </para>
		    <para>
			If an empty string <quote></quote> is used then the server will generate it
			from the request. In case of REGISTER requests To header field domain will
			be used (because this header field represents a user being registered), for
			all other messages From header field domain will be used.
		    </para>
		</listitem>
		<listitem>
		    <para><emphasis>table</emphasis> - Table to be used to lookup usernames and
			passwords (usualy subscribers table).
		    </para>
		</listitem>
	    </itemizedlist>
	    <example>
		<title><function moreinfo="none">www_authorize</function> usage</title>
		<programlisting format="linespecific">
...
if (www_authorize("iptel.org", "subscriber")) {
    www_challenge("iptel.org", "1");
};
...
</programlisting>
	    </example>
	</section>

	<section>
	    <title><function moreinfo="none">proxy_authorize(realm, table)</function></title>
	    <para>
		The function verifies credencials according to RFC2617. If the credentials are
		verified sucessfully 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 <function moreinfo="none">proxy_challenge</function> which will
		challenge the user again.
	    </para>
	    <para>Meaning of the parameters is as follows:</para>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>realm</emphasis> - Realm is a opaque string that the user agent
		    should present to the user so he can decide what username and password to
		    use. Usualy this is domain of the host the server is running on.
		    </para>
		    <para>
			If an empty string <quote></quote> is used then the server will generate it
			from the request. From header field domain will be used as realm.
		    </para>
		</listitem>
		<listitem>
		    <para><emphasis>table</emphasis> - Table to be used to lookup usernames and
			passwords (usualy subscribers table).
		    </para>
		</listitem>
	    </itemizedlist>
	    <example>
		<title>proxy_authorize usage</title>
		<programlisting format="linespecific">
...
if (!proxy_authorize("", "subscriber)) {
    proxy_challenge("", "1");  # Realm will be autogenerated
};
...
</programlisting>
	    </example>
	</section>
    </section>
</chapter>

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