1. ENUM Module

Juha Heinanen

   <jh@song.fi>

   Copyright © 2002, 2003 Juha Heinanen
   Revision History
   Revision $Revision: 1.8.10.1 $ $Date: 2008/06/11 13:11:59 $
     __________________________________________________________________

   1.1. Overview
   1.2. Parameters

        1.2.1. domain_suffix (string)
        1.2.2. tel_uri_params (string)

   1.3. Functions

        1.3.1. enum_query(),enum_query("suffix"),
                enum_query("suffix","service")

        1.3.2. is_from_user_e164()

1.1. Overview

   Enum module implements enum_query function that makes an enum query
   based on the user part of the current Request-URI. The function assumes
   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 enum_query forms a domain name, where the
   digits are in reverse order and separated by dots followed by domain
   suffix that by default is "e164.arpa.". For example, if the user part
   is +35831234567, the domain name will be
   "7.6.5.4.3.2.1.3.8.5.3.e164.arpa.".

   After forming the domain name, enum_query queries DNS for its NAPTR
   records. From the possible response enum_query 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!.

   Then enum_query sorts the chosen NAPTR records based on their <order,
   preference>. After sorting, enum_query 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, enum_query appends to it as tel URI parameters
   the value of tel_uri_params module parameter. Finally, enum_query
   associates a q value with each new URI based on the <order, preference>
   of the corresponding NAPTR record.

   When using enum_query without any parameters, it searches for NAPTRs
   with service type "e2u+sip" in the default enum tree. When using
   enum_query with a single parameter, this parameter will be used as enum
   tree. When using enum_query 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.

   Enum query returns 1 if the current Request URI was replaced and -1 if
   not.

   Enum module also implements is_from_user_e164 function that checks if
   the user part of from URI is an E164 number.

1.2. Parameters

   Revision History
   Revision $Revision: 1.8.10.1 $ $Date: 2008/06/11 13:11:59 $

1.2.1. domain_suffix (string)

   The domain suffix to be added to the domain name obtained from the
   digits of an E164 number. Can be overridden by a parameter to
   enum_query.

   Default value is "e164.arpa.".

   Example 1. Setting domain_suffix module parameter
modparam("enum", "domain_suffix", "e1234.arpa.")

1.2.2. tel_uri_params (string)

   A string whose contents is appended to each new tel URI in the request
   as tel URI parameters.

Note

   Currently SER does not support tel URIs. This means that at present
   tel_uri_params is appended as URI parameters to every URI.

   Default value is "".

   Example 2. Setting tel_uri_params module parameter
modparam("enum", "tel_uri_params", ";npdi")

1.3. Functions

   Revision History
   Revision $Revision: 1.8.10.1 $ $Date: 2008/06/11 13:11:59 $

1.3.1. enum_query(),enum_query("suffix"), enum_query("suffix","service")

   The function performs an enum query and rewrites the Request-URI with
   the result of the query. See Section 1.1, "Overview" for more
   information.

   Meaning of the parameters is as follows:
     * suffix - Suffix to be appended to the domain name.
     * service - Service string to be used in the service field.

   Example 3. enum_query usage
...
# 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");
...

1.3.2. is_from_user_e164()

   Checks if the user part of from URI an E164 number of the form
   +[0-9]{2,15}. Returns 1 if yes and -1 if not.

   Example 4. is_from_user_e164 usage
...
if (is_from_user_e164()) {
    ....
};
...
