dialplan Module

Andreea-Ancuta Onofrei

Voice Sistem SRL

Edited by

Andreea-Ancuta Onofrei

Edited by

Juha Heinanen

Edited by

Olle E. Johansson

Edited by

Luis Martin


Table of Contents

1. Admin Guide
1. Overview
2. How it works
3. Dialplan use cases
4. Dependencies
4.1. Kamailio Modules
4.2. External Libraries or Applications
5. Parameters
5.1. db_url (string)
5.2. table_name (string)
5.3. dpid_col (string)
5.4. pr_col (string)
5.5. match_op_col (string)
5.6. match_exp_col (string)
5.7. match_len_col (string)
5.8. subst_exp_col (string)
5.9. repl_exp_col (string)
5.10. attrs_col (string)
5.11. attrs_pvar (string)
5.12. fetch_rows (int)
5.13. match_dynamic (int)
6. Functions
6.1. dp_translate(id, [src[/dest]])
6.2. dp_reload()
7. RPC Commands
7.1. dialplan.dump
7.2. dialplan.reload
7.3. dialplan.translate
8. Installation
2. Developer's Guide

List of Examples

1.1. Set db_url parameter
1.2. Set table_name parameter
1.3. Set dpid_col parameter
1.4. Set pr_col parameter
1.5. Set match_op_col parameter
1.6. Set match_exp_col parameter
1.7. Set pr_col parameter
1.8. Set pr_col parameter
1.9. Set repl_exp_col parameter
1.10. Set attrs_col parameter
1.11. Set attrs_pvar parameter
1.12. Set fetch_rows parameter
1.13. Set match_dynamic parameter
1.14. dp_translate usage
1.15. dp_translate usage
1.16. Example of rules

Chapter 1. Admin Guide

1. Overview

This module implements generic string translations based on matching and replacement rules. It can be used to manipulate the request URI or a PV and to translate it to a new format/value. Dialplan can also be used to match a given URI and retrieve a set of attributes based on the match. It is a very flexible module that can be used to handle call routing, prefix rewrites and much more.

2. How it works

At startup the module will load a set of matching and transformation rules from a database. Rules are grouped into dialplans. Every database row will be stored in memory as a dialplan rule. Each rule will describe how the matching will be made, how the input value will be modified and which attributes that will be set for the matching transformation.

The module expects an input value which will be matched against a rule by using regular expressions (see 'man pcresyntax' for syntax), string or fnmatch (see 'man fnmatch') matching. Overlapping matching expressions can be controlled via priorities. One priority can have multiple dialplan entries. Priorities need not be numbered with consecutive numbers. The next higher priority will be used after trying to match all entries in one priority.

Once a rule is matched, the defined transformation (if any) is applied and the result is returned as output value. Also, if any string attribute is associated to the rule, this will be returned to the script along with the output value. This can be used to identify the used rule.

The first matching rule will be processed.

3. Dialplan use cases

The module can be used to implement multiple dialplans - to do auto-completion of dialed numbers (like national to international), to convert generic numbers to specific numbers (like for emergency numbers).

The module can also be used for detecting a range or sets of numbers mapped on a service/case - the attribute string can be used to store extra information about the service/case.

Non-SIP string translation can be implemented - like converting country names from all possible formats to a canonical format: (UK, England, United Kingdom) -> GB.

Any other string-base translation or detection for whatever other purposes.

4. Dependencies

4.1. Kamailio Modules

The following modules must be loaded before this module:

  • A database module

4.2. External Libraries or Applications

The following libraries or applications must be installed before running Kamailio with this module loaded:

  • libpcre - the libraries of PCRE.

5. Parameters

5.1. db_url (string)

The translation rules will be loaded using this database URL.

Default value is mysql://kamailio:kamailiorw@localhost/kamailio.

Example 1.1. Set db_url parameter

...
modparam("dialplan", "db_url", "mysql://user:passwb@localhost/db")
...

5.2. table_name (string)

The name of the database table used to load the translation rules.

Default value is dialplan.

Example 1.2. Set table_name parameter

...
modparam("dialplan", "table_name", "my_table")
...

5.3. dpid_col (string)

The column name used to store the dialplan group ID.

Default value is dpid.

Example 1.3. Set dpid_col parameter

...
modparam("dialplan", "dpid_col", "column_name")
...

5.4. pr_col (string)

The column name used to store the priority of the corresponding rule from the database row.

Default value is pr.

Example 1.4. Set pr_col parameter

...
modparam("dialplan", "pr_col", "column_name")
...

5.5. match_op_col (string)

The column name used to store the type of matching of the rule.

Default value is match_op.

Example 1.5. Set match_op_col parameter

...
modparam("dialplan", "match_op_col", "column_name")
...

5.6. match_exp_col (string)

The column name to store the rule match expression.

Default value is match_exp.

Example 1.6. Set match_exp_col parameter

...
modparam("dialplan", "match_exp_col", "column_name")
...

5.7. match_len_col (string)

The column name to store the length of a string matching the match expression.

Default value is match_len.

Example 1.7. Set pr_col parameter

...
modparam("dialplan", "match_len_col", "column_name")
...

5.8. subst_exp_col (string)

The column name to store the rule's substitution expression.

Default value is subst_exp.

Example 1.8. Set pr_col parameter

...
modparam("dialplan", "subst_exp_col", "column_name")
...

5.9. repl_exp_col (string)

The column name to store the rule's replacement expression.

Default value is repl_exp.

Example 1.9. Set repl_exp_col parameter

...
modparam("dialplan", "repl_exp_col", "column_name")
...

5.10. attrs_col (string)

The column name to store the rule's attributes to be set after match (see attrs_pvar )

Default value is attrs.

Example 1.10. Set attrs_col parameter

...
modparam("dialplan", "attrs_col", "column_name")
...

5.11. attrs_pvar (string)

The pseudovariable used to store the rule's attributes, after translation (when dp_translate() succeeds). This parameter can be an AVP or a script variable ($var())..

Default value is NULL.

Example 1.11. Set attrs_pvar parameter

...
modparam("dialplan", "attrs_pvar", "$avp(s:dest)")
...

5.12. fetch_rows (int)

The number of rows to be fetched at once from database

Default value is 1000.

Example 1.12. Set fetch_rows parameter

...
modparam("dialplan", "fetch_rows", 4000)
...

5.13. match_dynamic (int)

If set to 1, the match and substitution expressions can include script variables and their values are evaluated at runtime.

During the loading process, the values that contain variables are no longer pre-compiled to PCRE structure in memory, because the values change at runtime, thus expect slightly slower performances. Values without script variables are pre-compiled even if this parameter is enabled.

Default value is 0 (disabled).

Example 1.13. Set match_dynamic parameter

...
modparam("dialplan", "match_dynamic", 1)
...

6. Functions

6.1.  dp_translate(id, [src[/dest]])

Will try to translate src into dest according to the translation rules in the dialplan identified by id . If src/dest is missing the default parameter ruri.user/ruri.user will be used, thus translating the request URI user part. If only dest is missing, only matching and storing of the matching rule's attributes is done.

Returns 1, if translation succeeded, -1 in case of some error occurred, and -2 if dialplan with ID equal to id does not exist.

Meaning of the parameters is as follows:

  • id -the dialplan id of the possible matching rules. This parameter can have the following types:

    • integer- the dialplan id is statically assigned

    • avp var - the dialplan id is the value of an existing avp variable

    • script var - the dialplan id is the value of an existing script variable.

  • src/dest - input and output of the function.

    Input parameter src can be any pseudo variable. Output parameter dest can be:

    • R-URI

      - the string is the r-uri or r-uri user part

    • avp var

      - At input the function will get the input string from an existing avp variable. At output the function will add an avp with the value of the output string.

    • script var

      - At input the function will get the input string from an existing script variable. At output the function will set an script variable with the value of the output string.

This function can be used from ANY_ROUTE.

Example 1.14. dp_translate usage

...
dp_translate("240", "$ruri.user/$avp(s:dest)");
xlog("translated to var $avp(s:dest) \n");
...

Example 1.15. dp_translate usage

...
$avp(s:src) = $ruri.user;
dp_translate("$var(x)", "$avp(s:src)/$var(y)");
xlog("translated to var $var(y) \n");
...

6.2.  dp_reload()

Forces an update of the translation rules from the database.

Name: dp_reload

Parameters: none

This function can be used from ANY_ROUTE.

7. RPC Commands

7.1. dialplan.dump

Dumps the content of one dialplan ID

Name: dialplan.dump

Parameters: Dialplan ID

Example:

		kamcmd dialplan.dump 100

7.2. dialplan.reload

Forces an update of the translation rules from the database.

Name: dialplan.reload

Parameters: none

Example:

		kamcmd dialplan.reload

7.3. dialplan.translate

Will apply a translation rule identified by a dialplan id and an input string.

Name: dialplan.translate

Parameters: 2

  • Dial plan ID

  • Input String

Example:

		kamcmd dialplan.translate 1 "abcdxyz"

8. Installation

The modules requires one table in Kamailio database: dialplan. The SQL syntax to create them can be found in dialplan-create.sql script in the database directories in the kamailio/scripts folder. You can also find the complete database documentation on the project webpage, https://www.kamailio.org/docs/db-tables/kamailio-db-devel.html.

Some sample records from a dialplan table are presented in the next figure.

Example 1.16. Example of rules

...
dpid: 1
pr: 1
match_op: 1
match_exp: ^0[1-9][0-9]+$
match_len: 0
subst_exp: ^0([1-9][0-9]+)$
repl_exp: 0049\1
attrs: de
...
dpid: 1
pr: 2
match_op: 1
match_exp: ^0[1-9][0-9]+$
match_len: 0
subst_exp: ^0(.+)$
repl_exp: $var(prefix)\1
attrs: xyz
...

Note that you can use config variables in the replacement expression (repl_exp) field. However, not all of config variables are safe to use there - specifically the variables that have in their name other variables (variables with dynamic name). References to SIP message, private variables ($var(...)) and AVPs with static name are among those that are safe to use in replacement expressions.

The match_op field specify matching operator, valid values:

  • 0 - string comparison;
  • 1 - regular expression matching (pcre);
  • 2 - fnmatch (shell-like pattern) matching.

Chapter 2. Developer's Guide

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