Contributed Logic / file revision

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

 <chapter>

 	<title>&adminguide;</title>

 	<section id="sec-overview">

 	<title>Overview</title>

 	<para>

 		Enum module implements [i_]enum_query functions that make an enum query 

 		based on the user part of the current Request-URI. These functions

 		assume that the user part consists of an international phone number 

 		of the form +decimal-digits, where the number of digits is at

 		least 2 and at most 15. Out of this number 

 		<function moreinfo="none">enum_query</function> forms a domain name, 

 		where the digits are in reverse order and separated by dots followed by 

 		domain suffix that by default is <quote>e164.arpa.</quote>. For example, 

 		if the user part is +35831234567, the domain

 		name will be <quote>7.6.5.4.3.2.1.3.8.5.3.e164.arpa.</quote>.

 		<function moreinfo="none">i_enum_query</function> operates in a similar

 		fashion. The only difference is that it adds a label (default "i")

 		to branch off from the default, user-ENUM tree to an infrastructure ENUM tree.

 	</para>

 	<para>

 		After forming the domain name, 

 		<function moreinfo="none">enum_query</function> queries

 		DNS for its NAPTR records. From the possible response 

 		<function moreinfo="none">enum_query</function> chooses those records, 

 		whose flags field has string value "u", and whose services field has 

 		string value "e2u+[service:]sip" or 

 		"e2u+type[:subtype][+type[:subtype]...]" (case is ignored in both 

 		cases), and whose regexp field is of the form !pattern!replacement!.

 	</para>

 	<para>

 		Then <function moreinfo="none">enum_query</function> sorts the chosen 

 		NAPTR records based on their <order, preference>.  After sorting, 

 		<function moreinfo="none">enum_query</function> replaces the current 

 		Request URI by applying regexp of the most preferred NAPTR record its 

 		user part and appends to the request new branches by applying regexp of 

 		each remaining NAPTR record to the user part of the

 		current Request URI. If a new URI is a tel URI, 

 		<function moreinfo="none">enum_query</function> appends to it as tel 

 		URI parameters the value of tel_uri_params module parameter. Finally, 

 		<function moreinfo="none">enum_query</function> associates a q value 

 		with each new URI based on the <order, preference> of the 

 		corresponding NAPTR record.

 	</para>

 	<para>

 		When using <function moreinfo="none">enum_query</function> without any 

 		parameters, it searches for NAPTRs with service type "e2u+sip" in the 

 		default enum tree. When using 

 		<function moreinfo="none">enum_query</function> with a single parameter, 

 		this parameter will be used as enum tree. When using 

 		<function moreinfo="none">enum_query</function> 

 		with two parameters, the functionality depends on the first letter in 

 		the second parameter. When the first letter is not a '+' sign, the 

 		second parameter will be used to search for NAPTRs with service type 

 		"e2u+parameter:sip". When the second parameter starts with a '+' sign, 

 		the ENUM lookup also supports compound NAPTRs 

 		(e.g. "e2u+voice:sip+video:sip") and searching for multiple service 

 		types within one lookup. Multiple service types must be separeted 

 		by a '+' sign.

 	</para>

 	<para>

 		Most of the time you want to route based on the RURI.  On rare occasions

 		you may wish to route based on something else. The function

 		<function moreinfo="none">enum_pv_query</function> mimics the behavior

 		of the <function moreinfo="none">enum_query</function> function except the

 		E.164 number in its pseudo variable argument is used for the enum lookup instead of the user

 		part of the RURI.  Obviously the user part of the RURI is still used in the

 		NAPTR regexp.

 	</para>

 	<para>

 		Enum query returns 1 if the current Request URI was replaced 

 		and -1 if not.

 	</para>

 	<para>

 		In addition to standard ENUM, support for ISN (ITAD Subscriber

 		Numbers) is provided as well. To allow ISN lookups to resolve,

 		a different formatting algorithm is expected by the DNS server.

 		Whereas a ENUM NAPTR record expects a DNS query of the form

 		9.8.7.6.5.4.3.2.1.<suffix>, ISN method expects a DNS query of

 		the form 6.5.1212.<suffix>. That is, a valid ISN number includes

 		a prefix of '56' in the example. The rest of the number is a

 		ITAD (Internet Telephony Administrative Domain) as defined

 		in RFCs 3872 and 2871, and as allocated by the IANA in

 		http://www.iana.org/assignments/trip-parameters. The ITAD is

 		left intact and not refersed as ENUM requires. To learn more

 		about ISN please refer to documents at www.freenum.org.

 	</para>

 	<para>

 		To complete a ISN lookup on the user part of the Request-URI,

 		isn_query() is used instead of enum_query().

 	</para>

 	<para>

 		Enum module also implements is_from_user_enum function.

 		This function does an enum lookup on the from user and

 		returns true if found, false otherwise.

 	</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>No dependencies.</para>

 		</listitem>

 		</itemizedlist>

 	</para>

 	</section>

 	<section>

 	<title>Exported Parameters</title>

 	<section>

 		<title><varname>domain_suffix</varname> (string)</title>

 		<para>

 		The domain suffix to be added to the domain name obtained from

 		the digits of an <acronym>E164</acronym> number. Can be overridden 

 		by a parameter to enum_query.

 		</para>

 		<para>

 		Default value is <quote>e164.arpa.</quote>

 		</para>

 		<example>

 		<title>Setting domain_suffix module parameter</title>

 		<programlisting format="linespecific">

 modparam("enum", "domain_suffix", "e1234.arpa.")

 </programlisting>

 		</example>

 	</section>

 	<section>

 		<title><varname>tel_uri_params</varname> (string)</title>

 		<para>

 		A string whose contents is appended to each new tel URI in the 

 		request as tel URI parameters.

 		</para>

 		<note>

 		<para>

 			Currently &osips; does not support tel URIs. This means that at present

 			tel_uri_params is appended as URI parameters to every URI.

 		</para>

 		</note>

 		<para>

 		Default value is <quote></quote>

 		</para>

 		<example>

 		<title>Setting tel_uri_params module parameter</title>

 		<programlisting format="linespecific">

 modparam("enum", "tel_uri_params", ";npdi")

 </programlisting>

 		</example>

 	</section>

         <section>

                 <title><varname>i_enum_suffix</varname> (string)</title>

                 <para>

                 The domain suffix to be used for i_enum_query() lookups.

                 Can be overridden by a parameter to i_enum_query.

                 </para>

                 <para>

                 Default value is <quote>e164.arpa.</quote>

                 </para>

                 <example>

                 <title>Setting i_enum_suffix module parameter</title>

                 <programlisting format="linespecific">

 modparam("enum", "i_enum_suffix", "e1234.arpa.")

 </programlisting>

                 </example>

         </section>

         <section>

                 <title><varname>isn_suffix</varname> (string)</title>

                 <para>

                 The domain suffix to be used for isn_query() lookups. Can

                 be overridden by a parameter to isn_query.

                 </para>

                 <para>

                 Default value is <quote>freenum.org.</quote>

                 </para>

                 <example>

                 <title>Setting isn_suffix module parameter</title>

                 <programlisting format="linespecific">

 modparam("enum", "isn_suffix", "freenum.org.")

 </programlisting>

                 </example>

         </section>

         <section>

                 <title><varname>branchlabel</varname> (string)</title>

                 <para>

                 This parameter determines which label i_enum_query() will use

                 to branch off to the infrastructure ENUM tree.

                 </para>

                 <para>

                 Default value is <quote>"i"</quote>

                 </para>

                 <example>

                 <title>Setting branchlabel module parameter</title>

                 <programlisting format="linespecific">

 modparam("enum", "branchlabel", "i")

 </programlisting>

                 </example>

         </section>

         <section>

                 <title><varname>bl_algorithm</varname> (string)</title>

                 <para>

                 This parameter determines which algorithm i_enum_query() will use

                 to select the position in the DNS tree where the infrastructure tree

                 branches off the user ENUM tree.

                 </para>

                 <para>

                 If set to "cc", i_enum_query() will always inserts the

                 label at the country-code level.

                 Examples: i.1.e164.arpa, i.3.4.e164.arpa, i.2.5.3.e164.arpa

                 </para>

                 <para>

                 If set to "txt", i_enum_query() will look for a TXT record at

                 [branchlabel].[reverse-country-code].[i_enum_suffix] to indicate after how many digits the

                 label should in inserted.

                 <example>

                 <title>Zone file example</title>

                 <programlisting format="linespecific">

 i.1.e164.arpa.                     IN TXT   "4"

 9.9.9.8.7.6.5.i.4.3.2.1.e164.arpa. IN NAPTR "NAPTR content for  +1 234 5678 999"

 </programlisting>

                 </example>

                 </para>

                 <para>

                 If set to "ebl", i_enum_query() will look for an EBL (ENUM Branch Label) record at

                 [branchlabel].[reverse-country-code].[i_enum_suffix]. See http://www.ietf.org/internet-drafts/draft-lendl-enum-branch-location-record-00.txt for a description of that record and the

                 meaning of the fields. The RR type for the EBL has not been allocated yet.

                 This version of the code uses 65300. See resolve.h.

                 <example>

                 <title>Zone file example</title>

                 <programlisting format="linespecific">

 i.1.e164.arpa.     TYPE65300  \# 14 (

                               04    ; position

                               01 69 ; separator

                               04 65 31 36 34 04 61 72 70 61 00 ; e164.arpa

 ;                               )

 9.9.9.8.7.6.5.i.4.3.2.1.e164.arpa. IN NAPTR "NAPTR content for  +1 234 5678 999"

 </programlisting>

                 </example>

                 </para>

                 <para>

                 Default value is <quote>cc</quote>

                 </para>

                 <example>

                 <title>Setting the bl_algorithm module parameter</title>

                 <programlisting format="linespecific">

 modparam("enum", "bl_algorithm", "txt")

 </programlisting>

                 </example>

         </section>

 	</section>

 	<section>

 	<title>Exported Functions</title>

 	<section>

 		<title>

 		<function moreinfo="none">enum_query(["suffix"[,"service"]])</function>

 		</title>

 		<para>

 		The function performs an enum query and rewrites the Request-URI with 

 		the result of the query. See <xref linkend="sec-overview"/> for more 

 		information.

 		</para>

 		<para>Meaning of the parameters is as follows:</para>

 		<itemizedlist>

 		<listitem>

 			<para><emphasis>suffix</emphasis> - Suffix to be appended to the 

 			domain name.

 			</para>

 		</listitem>

 		<listitem>

 			<para><emphasis>service</emphasis> - Service string to be used in 

 			the service field.

 			</para>

 		</listitem>

 		</itemizedlist>

 		<para>

 		This function can be used from REQUEST_ROUTE.

 		</para>

 		<example>

 		<title><function moreinfo="none">enum_query</function> usage</title>

 		<programlisting format="linespecific">

 ...

 # search for "e2u+sip" in freenum.org 

 enum_query("freenum.org.");

 ...

 # search for "e2u+sip" in default tree (configured as parameter)

 enum_query();

 ...

 # search for "e2u+voice:sip" in e164.arpa

 enum_query("e164.arpa.","voice");

 ...

 # search for service type "sip" or "voice:sip" or "video:sip"

 # note the '+' sign in front of the second parameter

 enum_query("e164.arpa.","+sip+voice:sip+video:sip");

 ...

 # quering for service sip and voice:sip

 enum_query("e164.arpa.");

 enum_query("e164.arpa.","voice");

 # or use instead

 enum_query("e164.arpa.","+sip+voice:sip");

 ...

 </programlisting>

 		</example>

 	</section>

 	<section>

 		<title>

 		<function moreinfo="none">enum_pv_query("pvar"[,"suffix"[,"service"]])</function>

 		</title>

 		<para>

 		The function performs an enum query on E.164 number stored

 		in its pseudo variable argument and rewrites the Request-URI with 

 		the result of the query. See <xref linkend="sec-overview"/> for more 

 		information.

 		</para>

 		<para>Meaning of the parameters is as follows:</para>

 		<itemizedlist>

 		<listitem>

 			<para><emphasis>pvar</emphasis> - Pseudo

 		variable that holds an E.164 number on which enum

 		query is performed.

 			</para>

 		</listitem>

 		<listitem>

 			<para><emphasis>suffix</emphasis> - Suffix to be appended to the 

 			domain name.

 			</para>

 		</listitem>

 		<listitem>

 			<para><emphasis>service</emphasis> - Service string to be used in 

 			the service field.

 			</para>

 		</listitem>

 		</itemizedlist>

 		<para>

 		This function can be used from REQUEST_ROUTE.

 		</para>

 		<example>

 		<title><function moreinfo="none">enum_pv_query</function> usage</title>

 		<programlisting format="linespecific">

 ...

 # search for "e2u+sip" in freenum.org 

 enum_pv_query("$avp(i:100)", "freenum.org.");

 ...

 # search for "e2u+sip" in default tree (configured as parameter)

 enum_pv_query("$fU");

 ...

 # search for "e2u+voice:sip" in e164.arpa

 enum_pv_query("$avp(i:100)","e164.arpa.","voice");

 ...

 # search for service type "sip" or "voice:sip" or "video:sip"

 # note the '+' sign in front of the second parameter

 enum_pv_query("$fU","e164.arpa.","+sip+voice:sip+video:sip");

 ...

 # quering for service sip and voice:sip

 enum_pv_query("$avp(i:100)","e164.arpa.");

 enum_pv_query("$avp(i:100)","e164.arpa.","voice");

 # or use instead

 enum_pv_query("$avp(i:100)","e164.arpa.","+sip+voice:sip");

 ...

 </programlisting>

 		</example>

 	</section>

         <section>

                 <title>

                 <function moreinfo="none">i_enum_query(["suffix"[,"service"]])</function>

                 </title>

                 <para>

                 The function performs an enum query and rewrites the Request-URI with

                 the result of the query. This the Infrastructure-ENUM version of enum_query().

                 The only difference to enum_query() is in the calculation of the

                 FQDN where NAPTR records are looked for.

                 </para>

                 <para>

                 See ftp://ftp.rfc-editor.org/in-notes/internet-drafts/draft-haberler-carrier-enum-01.txt

                 for the rationale behind this function.

                 </para>

         </section>

 	<section>

 		<title>

 		<function moreinfo="none">isn_query(["suffix"[,"service"]])</function>

 		</title>

 		<para>

 		The function performs a ISN query and rewrites the Request-URI with 

 		the result of the query. See <xref linkend="sec-overview"/> for more 

 		information.

 		</para>

 		<para>Meaning of the parameters is as follows:</para>

 		<itemizedlist>

 		<listitem>

 			<para><emphasis>suffix</emphasis> - Suffix to be appended to the 

 			domain name.

 			</para>

 		</listitem>

 		<listitem>

 			<para><emphasis>service</emphasis> - Service string to be used in 

 			the service field.

 			</para>

 		</listitem>

 		</itemizedlist>

 		<para>

 			This function can be used from REQUEST_ROUTE.

 		</para>

 		<para>

 			See ftp://ftp.ietf.org/rfc/rfc3872.txt and

 			ftp://ftp.ietf.org/rfc/rfc2871.txt for information

 			regarding the ITAD part of the ISN string.

 		</para>

 		<example>

 		<title><function moreinfo="none">isn_query</function> usage</title>

 		<programlisting format="linespecific">

 ...

 # search for "e2u+sip" in freenum.org 

 isn_query("freenum.org.");

 ...

 # search for "e2u+sip" in default tree (configured as parameter)

 isn_query();

 ...

 # search for "e2u+voice:sip" in freenum.org

 isn_query("freenum.org.","voice");

 ...

 </programlisting>

 		</example>

 	</section>

 	<section>

 		<title><function moreinfo="none">is_from_user_enum()</function></title>

 		<para>

 		Checks if the user part of from <abbrev>URI</abbrev>

 		is found in an enum lookup.

 		Returns 1 if yes and -1 if not.

 		</para>

 		<para>

 		This function can be used from REQUEST_ROUTE.

 		</para>

 		<example>

 		<title><function moreinfo="none">is_from_user_enum</function> usage</title>

 		<programlisting format="linespecific">

 ...

 if (is_from_user_enum()) {

 	....

 };

 ...

 </programlisting>

 		</example>

 	</section>

 	</section>

 </chapter>