reference.sgml

用来作为linux中SIP SERVER,完成VOIP网络电话中服务器的功能

		    <para>
			<command>log([level], message)</command> - Log a message.
		    </para>
		    <para>
			<emphasis>Example:</emphasis> log(1, "This is a message with high log-level set to 1\n");
		    </para>
		    <para>
			Logging is very useful for troubleshooting or attracting administrator's
			attention to unusual situations. <application moreinfo="none">ser</application>
			reports log messages to <application moreinfo="none">syslog</application>
			facility unless it is configured to print them to <filename moreinfo="none">stderr</filename>
			with the <varname>log_stderr</varname> configuration option. Log messages
			are only issued if their log level exceeds threshold set with the
			<varname>debug</varname> configuration option. If log level is omitted,
			messages are issued at log level 4.
		</para>
		</listitem>

	    </itemizedlist>




	    <itemizedlist>
		<title>Miscellaneous</title>
		<listitem>
		    <para>
			<command>len_gt</command> - If length of the message is greater than value given as parameter, the
			command will return 1 (indicating true). Otherwise -1 (indicating false) will be returned. It may 
			take 'max_len' as parameter, in which case message size is limited
			to internal buffer size BUF_SIZE (3040 by default).
		    </para>
		    <example>
			<title>Use of <command>len_gt</command></title>
			<programlisting format="linespecific">
# deny all requests larger in size than 1 kilobyte
if (len_gt(1024)) {
    sl_send_reply("513", "Too big");
    break;
};
			</programlisting>
		    </example>
		</listitem>
	    </itemizedlist>
	</section>
	<section>
	    <title>Command Line Parameters</title>
	    <note>
		<para>
		    Command-Line parameters may be overridden by configuration
		    file options which take precedence over them.
		</para>
	    </note>
	    <itemizedlist>
		<listitem>
		    <para>
			<emphasis>-h</emphasis> - Displays a short usage description, including all available options.
		    </para>
		</listitem>
		<listitem>
		    <para>
			<emphasis>-c</emphasis> - Performs loop checks and computes branches.
		    </para>
		</listitem>
		<listitem>
		    <para>
			<emphasis>-r</emphasis> - Uses dns to check if it is necessary to add a "received=" field to a via.
		    </para>
		</listitem>
		<listitem>
		    <para>
			<emphasis>-R</emphasis> - Same as -r but uses reverse dns.
		    </para>
		</listitem>
		<listitem>
		    <para>
			<emphasis>-v</emphasis> - Turns on via host checking when forwarding replies.
		    </para>
		</listitem>
		<listitem>
		    <para>
			<emphasis>-d</emphasis> - Turns on debugging, multiple -d increase debugging level.
		    </para>
		</listitem>
		<listitem>
		    <para>
			<emphasis>-D</emphasis> - Runs ser in the foreground (it doesn't fork into daemon mode).
		    </para>
		</listitem>
		<listitem>
		    <para>
			<emphasis>-E</emphasis> - Sends all the log messages to stderr.
		    </para>
		</listitem>
		<listitem>
		    <para>
			<emphasis>-V</emphasis> - Displays the version number.
		    </para>
		</listitem>
		<listitem>
		    <para>
			<emphasis>-f config-file</emphasis> - Reads the configuration from "config-file" (default ./ser.cfg).
		    </para>
		</listitem>
		<listitem>
		    <para>
			<emphasis>-l address</emphasis> - Listens on the specified address. Multiple -l mean listening 
			on multiple addresses. The default behavior is to listen on all the ipv4 interfaces.
		    </para>
		</listitem>
		<listitem>
		    <para>
			<emphasis>-p port</emphasis> - Listens on the specified port (default 5060). It applies to the last 
			address specified with -l and to all the following that do not have a corresponding -p.
		    </para>
		</listitem>
		<listitem>
		    <para>
			<emphasis>-n processes-no</emphasis> - Specifies the number of children processes forked per 
			interface (default 8).
		    </para>
		</listitem>
		<listitem>
		    <para>
			<emphasis>-b max_rcv_buf_size</emphasis> - Maximum receive buffer size which will not be exceeded by 
			the auto-probing procedure even if the OS allows.
		    </para>
		</listitem>
		<listitem>
		    <para>
			<emphasis>-m shared_mem_size</emphasis> - Size of the shared memory which will be allocated (in Megabytes).
		    </para>
		</listitem>
		<listitem>
		    <para>
			<emphasis>-w working-dir</emphasis> - Specifies the working directory. In the very improbable event 
			that will crash, the core file will be generated here.
		    </para>
		</listitem>
		<listitem>
		    <para>
			<emphasis>-t chroot-dir</emphasis> - Forces ser to chroot after reading the config file.
		    </para>
		</listitem>
		<listitem>
		    <para>
			<emphasis>-u uid</emphasis> - Changes the user id under which ser runs.
		    </para>
		</listitem>
		<listitem>
		    <para>
			<emphasis>-g gid</emphasis> - Changes the group id under which ser runs.
		    </para>
		</listitem>
		<listitem>
		    <para>
			<emphasis>-P pid-file</emphasis> - Creates a file containing the pid of the main ser process.
		    </para>
		</listitem>
		<listitem>
		    <para>
			<emphasis>-i fifo-path</emphasis> - Creates a fifo, useful for monitoring ser status.
		    </para>
		</listitem>
	    </itemizedlist>
	</section>




	<section id="modulereference">
	    <title>Modules</title>
	    <para>
		Module description is currently located in READMEs of
		respective module directories. <filename moreinfo="none">README-MODULES</filename>
		lists all available modules, including their maturity status.
		In the current <application moreinfo="none">ser</application>
		distribution, there are the following modules:
		<itemizedlist>
		    <listitem>
			<para>
			    <emphasis>
				acc
			    </emphasis>
			    -- call accounting using <application moreinfo="none">syslog</application> facility.
				RADIUS and mysql support can be compiled in.
			    Depends on tm.
			</para>
		    </listitem>
		    <listitem>
			<para>
			    <emphasis>
				auth, auth_db, auth_radius
			    </emphasis>
			    -- digest authentication. Depends on sl and mysql.
			</para>
		    </listitem>

			<listitem>
				<para>
					<emphasis>domain</emphasis> -- checks URIs whether they belong
					in a list of served domains or not.
				</para>
			</listitem>



			<listitem>
				<para>
					<emphasis>ENUM</emphasis> -- E.164 phone number resolution using ENUM.
				</para>
			</listitem>


		    <listitem>
			<para>
			    <emphasis>
				exec
			    </emphasis>
			    -- execution of shell programs.
			</para>
		    </listitem>

		    <listitem>
			<para>
			    <emphasis>
				group, group_radius
			    </emphasis>
			    -- checks membership of users in groups
			</para>
		    </listitem>

		    <listitem>
			<para>
			    <emphasis>
				jabber
			    </emphasis> -- gateway between SIMPLE and Jabber instant messaging. Depends
			    on tm and mysql.
			</para>
		    </listitem>
		    <listitem>
			<para>
			    <emphasis>
				maxfwd
			    </emphasis>
			    -- checking max-forwards header field.
			</para>
		    </listitem>
		    <listitem>
			<para>
			    <emphasis>msilo</emphasis>

			-- message silo. Store for undelivered instant messages. Depends on tm and mysql.
			    </para>
		    </listitem>

		    <listitem>
			<para>
			    <emphasis>
				mysql
			    </emphasis>
			    -- mysql database back-end.
			    </para>
		    </listitem>

		    <listitem>
			<para>
			    <emphasis>
					nathelper	
			    </emphasis>
			    -- facilitates NAT traversal for symmetric SIP phones such as ATA.
			    </para>
		    </listitem>

		    <listitem>
			<para>
			    <emphasis>
					pa
			    </emphasis>
			    -- presence agent
			    </para>
		    </listitem>

		    <listitem>
			<para>
			    <emphasis>
				registrar, usrloc
			    </emphasis>
			    -- User Location database. Works in in-memory mode or with mysql persistence
			    support. Depends on sl, and on mysql if configured for use with mysql.
			</para>
		    </listitem>
		    <listitem>
			<para>
			    <emphasis>
				rr
			    </emphasis>
			    -- Record Routing (strict and loose)
			</para>
		    </listitem>
		    <listitem>
			<para>
			    <emphasis>
				sl
			    </emphasis>
			    -- stateless User Agent server.
			</para>
		    </listitem>
		    <listitem>
			<para>
			    <emphasis>
				sms
			    </emphasis>
			    -- SIMPLE/SMS gateway. Depends on tm. Takes special hardware.
			</para>
		    </listitem>
			<listitem>
			<para>
				<emphasis>textops</emphasis> -- textual database back-end.
			</para>
			</listitem>
				
		    <listitem>			
			<para>
			    <emphasis>
				tm
			    </emphasis>
			    -- transaction manager (stateful processing).
			</para>
		    </listitem>

		    <listitem>			
			<para>
			    <emphasis>
				uri, uri_radius
			    </emphasis>
			    -- checks digest identity against header URIs or a database list
			</para>
		    </listitem>

		</itemizedlist>
	    </para>
	    <para>
		The most frequently used actions exported by modules are summarized
		in <xref linkend="moduleactions">. For a full explanation of 
		module actions, see documentation in respective module directories
		in source distribution of <application moreinfo="none">ser</application>.
	    </para>
	    <table id="moduleactions">
		<title>Frequently Used Module Actions</title>
		<tgroup cols="4">
		    <thead>
			<row>			    
			    <entry>
				Command
			    </entry>
			    <entry>
				Modules
			    </entry>
			    <entry>
				Parameters
			    </entry>
			    <entry>
				Comments
			    </entry>
			</row>
		    </thead>

		    <tbody>

			<row>
			    <entry>
				append_hf
			    </entry>
			    <entry>
				textops
				</entry>
			    <entry>
				header field
				</entry>
			    <entry>
				append a header field to the end of request's header
				</entry>
			    </row>
			<row>
			    <entry>
				check_from
			    </entry>
			    <entry>
				uri
			    </entry>
			    <entry>
				none
			    </entry>
			    <entry>
				check if username in from header field matches authentication id
			    </entry>
			</row>
			<row>
			    <entry>
				check_to
			    </entry>
			    <entry>
				uri
			    </entry>
			    <entry>
				none
			    </entry>
			    <entry>
				check if username in To header field matched authentication id
			    </entry>
			</row>
			<row>
			    <entry>
				exec_dset
			    </entry>
			    <entry>
				exec
			    </entry>
			    <entry>
				command name
			    </entry>
			    <entry>
				execute an external command and replace destination set with
				its output
			    </entry>
			</row>
			<row>
			    <entry>
				exec_msg
			    </entry>
			    <entry>
				exec
			    </entry>
			    <entry>
				command name
			    </entry>
			    <entry>
				execute an external command and pass received SIP request
				to its input
			    </entry>
			</row>
			<row>
			    <entry>
				is_user
			    </entry>
			    <entry>
				uri
			    </entry>
			    <entry>
				user id
			    </entry>
			    <entry>
				returns true if request credentials belong to a user
			    </entry>
			</row>
			<row>
			    <entry>
				is_user_in
			    </entry>
			    <entry>
				auth
			    </entry>
			    <entry>
				user, group
			    </entry>
			    <entry>
				check if user is member of a group; user can be gained
				from request URI ("Request-URI"), To header field ("To"),
				From header field ("From") or digest credentials
				("Credentials")
			    </entry>
			</row>
			<row>
			    <entry>
				lookup
			    </entry>
			    <entry>
				usrloc
			    </entry>
			    <entry>
				table name
			    </entry>
			    <entry>
				attempt to translate request URI using user location database;
				returns false if no contact for user found;
			    </entry>
			</row>
			<row>
			    <entry>