userblacklist Module

Hardy Kahl

1&1 Internet AG

Edited by

Henning Westerholt

1&1 Internet AG
Revision History
Revision $Revision$ $Date$

Table of Contents

1. Admin Guide
1. Overview
2. Dependencies
2.1. Kamailio Modules
2.2. External Libraries or Applications
3. Exported Parameters
3.1. use_domain (integer)
4. Exported Functions
4.1. check_user_blacklist (string user, string domain, string number, string table)
4.2. check_user_whitelist (string user, string domain, string number, string table)
4.3. check_blacklist ([string table])
5. MI Commands
5.1. reload_blacklist
6. Installation and Running
6.1. Database setup
2. Module parameter for database access.
1. db_url (String)
2. userblacklist_table (String)
3. userblacklist_id_col (string)
4. userblacklist_username_col (string)
5. userblacklist_domain_col (string)
6. userblacklist_prefix_col (string)
7. userblacklist_whitelist_col (string)
8. globalblacklist_table (String)
9. globalblacklist_id_col (string)
10. globalblacklist_prefix_col (string)
11. globalblacklist_whitelist_col (string)
12. globalblacklist_description_col (string)

List of Examples

1.1. Set use_domain parameter
1.2. check_user_blacklist usage
1.3. check_user_blacklist usage
1.4. check_blacklist usage
1.5. reload_blacklists usage
1.6. Example database content - globalblacklist table
1.7. Example database content - userblacklist table
2.1. Set db_url parameter
2.2. Set userblacklist_table parameter
2.3. Set userblacklist_id_col parameter
2.4. Set userblacklist_username_col parameter
2.5. Set userblacklist_domain_col parameter
2.6. Set userblacklist_prefix_col parameter
2.7. Set userblacklist_whitelist_col parameter
2.8. Set globalblacklist_table parameter
2.9. Set globalblacklist_id_col parameter
2.10. Set globalblacklist_prefix_col parameter
2.11. Set globalblacklist_whitelist_col parameter
2.12. Set globalblacklist_description_col parameter

Chapter 1. Admin Guide

1. Overview

The userblacklist module allows Kamailio to handle blacklists on a per user basis. This information is stored in a database table, which is queried to decide if the number (more exactly, the request URI user) is blacklisted or not.

An additional functionality that this module provides is the ability to handle global blacklists. This lists are loaded on startup into memory, thus providing a better performance then in the userblacklist case. This global blacklists are useful to only allow calls to certain international destinations, i.e. block all not whitelisted numbers. They could also used to prevent the blacklisting of important numbers, as whitelisting is supported too. This is useful for example to prevent the customer from blocking emergency call number or service hotlines.

The module exports three functions, check_blacklist check_user_blacklist and check_user_whitelist for usage in the config file. Furthermore its provide a FIFO function to reload the global blacklist cache.

Please note that only numerical strings for matching are supported at the moment (the used library supports this already, but its not yet implemented in the module). Non-digits on the beginning of the matched string are skipped, any later non-digits will stop the matching on this position.

2. Dependencies

2.1. Kamailio Modules

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

  • database -- Any database module

2.2. External Libraries or Applications

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

  • none

3. Exported Parameters

3.1. use_domain (integer)

If set to non-zero value, the domain column in the userblacklist is used.

Default value is “0”.

Example 1.1. Set use_domain parameter

...
modparam("userblacklist", "use_domain", 0)
...

4. Exported Functions

4.1.  check_user_blacklist (string user, string domain, string number, string table)

Finds the longest prefix that matches the request URI user (or the number parameter) for the given user and domain name in the database. If a match is found and it is not set to whitelist, false is returned. Otherwise, true is returned. Pseudo-variables or AVPs can be used for the user, domain and number parameters. The number and table variables are optional, the defaults are used if they are ommited. The number parameter can be used to check for example against the from URI user.

Example 1.2. check_user_blacklist usage

...
$avp(i:80) = $rU;
# rewrite the R-URI
if (!check_user_blacklist("$avp(i:80)", "$avp(i:82)")) {
	sl_send_reply("403", "Forbidden");
	exit;
}
...

4.2.  check_user_whitelist (string user, string domain, string number, string table)

Finds the longest prefix that matches the request URI user (or the number parameter) for the given user and domain name in the database. If a match is found and it is set to whitelist, true is returned. Otherwise, false is returned. Pseudo-variables or AVPs can be used for the user, domain and number parameters. The number and table variables are optional, the defaults are used if they are ommited. The number parameter can be used to check for example against the from URI user.

Example 1.3. check_user_blacklist usage

...
$avp(i:80) = $rU;
# rewrite the R-URI
if (!check_user_whitelist("$avp(i:80)", "$avp(i:82)")) {
	# process request
	exit;
}
...

4.3.  check_blacklist ([string table])

Finds the longest prefix that matches the request URI for the given table. If a match is found and it is not set to whitelist, false is returned. Otherwise, true is returned. If no table is given, then globalblacklist_table is used.

Example 1.4. check_blacklist usage

...
if (!check_blacklist("globalblacklist")) {
	sl_send_reply("403", "Forbidden");
	exit;
}
...

5. MI Commands

5.1.  reload_blacklist

Reload the internal global blacklist cache. This is necessary after the database tables for the global blacklist have been changed.

Example 1.5. reload_blacklists usage

...
kamctl fifo reload_blacklist
...

6. Installation and Running

6.1. Database setup

Before running Kamailio with userblacklist, you have to setup the database table where the module will read the blacklist data. For that, if the table was not created by the installation script or you choose to install everything by yourself you can use the userblacklist-create.sql SQL script in the database directories in the kamailio/scripts folder as template. Database and table name can be set with module parameters so they can be changed, but the name of the columns must be as they are in the SQL script. You can also find the complete database documentation on the project webpage, http://www.kamailio.org/docs/db-tables/kamailio-db-devel.html.

Example 1.6. Example database content - globalblacklist table

...
+----+-----------+-----------+
| id | prefix    | whitelist |
+----+-----------+-----------+
|  1 |           |         0 |
|  2 | 1         |         1 |
|  3 | 123456    |         0 |
|  4 | 123455787 |         0 |
+----+-----------+-----------+
...

This table will setup a global blacklist for all numbers, only allowing calls starting with “1”. Numbers that starting with “123456” and “123455787” are also blacklisted, because the longest prefix will be matched.

Example 1.7. Example database content - userblacklist table

...
+----+----------------+-------------+-----------+-----------+
| id | username       | domain      | prefix    | whitelist |
+----+----------------+-------------+-----------+-----------+
| 23 | 49721123456788 |             | 1234      |         0 |
| 22 | 49721123456788 |             | 123456788 |         1 |
| 21 | 49721123456789 |             | 12345     |         0 |
| 20 | 494675231      |             | 499034133 |         1 |
| 19 | 494675231      | test        | 499034132 |         0 |
| 18 | 494675453      | test.domain | 49901     |         0 |
| 17 | 494675454      |             | 49900     |         0 |
+----+----------------+-------------+-----------+-----------+
...

This table will setup user specific blacklists for certain usernames. For example for user “49721123456788” the prefix “1234” will be not allowed, but the number “123456788” is allowed. Additionally a domain could be specified that is used for username matching if the “use_domain” parameter is set.

Chapter 2. Module parameter for database access.

1. db_url (String)

URL to the database containing the data.

Default value is “mysql://openserro:openserro@localhost/openser”.

Example 2.1. Set db_url parameter

...
modparam("userblacklist", "db_url", "dbdriver://username:password@dbhost/dbname")
...

2. userblacklist_table (String)

Name of the userblacklist table for the userblacklist module.

Default value is “userblacklist”.

Example 2.2. Set userblacklist_table parameter

...
modparam("userblacklist", "userblacklist_table", "userblacklist")
...

3. userblacklist_id_col (string)

unique ID

Example 2.3. Set userblacklist_id_col parameter

...
modparam("userblacklist", "userblacklist_id_col", "id")
...

4. userblacklist_username_col (string)

The user that is used for the blacklist lookup.

Example 2.4. Set userblacklist_username_col parameter

...
modparam("userblacklist", "userblacklist_username_col", "username")
...

5. userblacklist_domain_col (string)

The domain that is used for the blacklist lookup.

Example 2.5. Set userblacklist_domain_col parameter

...
modparam("userblacklist", "userblacklist_domain_col", "domain")
...

6. userblacklist_prefix_col (string)

The prefix that is matched for the blacklist.

Example 2.6. Set userblacklist_prefix_col parameter

...
modparam("userblacklist", "userblacklist_prefix_col", "prefix")
...

7. userblacklist_whitelist_col (string)

Specify if this a blacklist (0) or a whitelist (1) entry.

Example 2.7. Set userblacklist_whitelist_col parameter

...
modparam("userblacklist", "userblacklist_whitelist_col", "whitelist")
...

8. globalblacklist_table (String)

Name of the globalblacklist table for the userblacklist module. Please note that this table is used when the check_blacklist function is called with no parameters.

Default value is “globalblacklist”.

Example 2.8. Set globalblacklist_table parameter

...
modparam("userblacklist", "globalblacklist_table", "globalblacklist")
...

9. globalblacklist_id_col (string)

unique ID

Example 2.9. Set globalblacklist_id_col parameter

...
modparam("userblacklist", "globalblacklist_id_col", "id")
...

10. globalblacklist_prefix_col (string)

The prefix that is matched for the blacklist.

Example 2.10. Set globalblacklist_prefix_col parameter

...
modparam("userblacklist", "globalblacklist_prefix_col", "prefix")
...

11. globalblacklist_whitelist_col (string)

Specify if this a blacklist (0) or a whitelist (1) entry.

Example 2.11. Set globalblacklist_whitelist_col parameter

...
modparam("userblacklist", "globalblacklist_whitelist_col", "whitelist")
...

12. globalblacklist_description_col (string)

A comment for the entry.

Example 2.12. Set globalblacklist_description_col parameter

...
modparam("userblacklist", "globalblacklist_description_col", "description")
...