Enum Module

Juha Heinanen


Table of Contents
1. User's Guide
1.1. Overview
1.2. Dependencies
1.3. Exported Parameters
1.3.1. domain_suffix (string)
1.3.2. tel_uri_params (string)
1.4. Exported Functions
1.4.1. enum_query(),enum_query("suffix"), enum_query("suffix", "service")
1.4.2. is_from_user_e164()
2. Developer's Guide
3. Frequently Asked Questions
List of Examples
1-1. Setting domain_suffix module parameter
1-2. Setting tel_uri_params module parameter
1-3. enum_query usage
1-4. is_from_user_e164 usage

Chapter 1. User's Guide

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. Dependencies

The module depends on the following modules (in the other words the listed modules must be loaded before this module):

  • No dependencies.


1.3. Exported Parameters

1.3.1. 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 1-1. Setting domain_suffix module parameter

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

1.3.2. tel_uri_params (string)

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

Note

Currently OpenSER 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 1-2. Setting tel_uri_params module parameter

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

1.4. Exported Functions

1.4.1. 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> 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.

This function can be used from REQUEST_ROUTE.

Example 1-3. 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");
...

1.4.2. 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.

This function can be used from REQUEST_ROUTE.

Example 1-4. is_from_user_e164 usage

...
if (is_from_user_e164()) {
	....
};
...

Chapter 2. Developer's Guide

The module does not provide any API to use in other OpenSER modules.


Chapter 3. Frequently Asked Questions

3.1. Where can I find more about OpenSER?
3.2. Where can I post a question about this module?
3.3. How can I report a bug?

3.1. Where can I find more about OpenSER?

Take a look at http://openser.org/.

3.2. Where can I post a question about this module?

First at all check if your question was already answered on one of our mailing lists:

E-mails regarding any stable OpenSER release should be sent to and e-mails regarding development versions should be sent to .

If you want to keep the mail private, send it to .

3.3. How can I report a bug?

Please follow the guidelines provided at: http://openser.org/bugs.