userblocklist Module

Edited by

Henning Westerholt

1&1 Internet AG

Pawel Kuzak

1&1 Internet AG

Table of Contents

1. Admin Guide
1. Overview
2. Dependencies
2.1. Kamailio Modules
2.2. External Libraries or Applications
3. Parameters
3.1. use_domain (integer)
3.2. match_mode (integer)
3.3. db_url (String)
3.4. userblocklist_table (String)
3.5. userblocklist_id_col (string)
3.6. userblocklist_username_col (string)
3.7. userblocklist_domain_col (string)
3.8. userblocklist_prefix_col (string)
3.9. userblocklist_allowlist_col (string)
3.10. globalblocklist_table (String)
3.11. globalblocklist_id_col (string)
3.12. globalblocklist_prefix_col (string)
3.13. globalblocklist_allowlist_col (string)
3.14. globalblocklist_description_col (string)
4. Functions
4.1. check_user_blocklist (string user, string domain, string number, string table)
4.2. check_user_allowlist (string user, string domain, string number, string table)
4.3. check_blocklist ([string table])
4.4. check_allowlist (string table)
5. RPC Commands
5.1. userblocklist.reload_blocklist
6. MI Commands
6.1. reload_blocklist
6.2. dump_blocklist
6.3. check_blocklist prefix
6.4. check_allowlist prefix
6.5. check_userblocklist user [domain] prefix
6.6. check_userallowlist user [domain] prefix
7. Installation and Running
7.1. Database setup

List of Examples

1.1. Set use_domain parameter
1.2. Set match_mode parameter
1.3. Set db_url parameter
1.4. Set userblocklist_table parameter
1.5. Set userblocklist_id_col parameter
1.6. Set userblocklist_username_col parameter
1.7. Set userblocklist_domain_col parameter
1.8. Set userblocklist_prefix_col parameter
1.9. Set userblocklist_allowlist_col parameter
1.10. Set globalblocklist_table parameter
1.11. Set globalblocklist_id_col parameter
1.12. Set globalblocklist_prefix_col parameter
1.13. Set globalblocklist_allowlist_col parameter
1.14. Set globalblocklist_description_col parameter
1.15. check_user_blocklist usage
1.16. check_user_allowlist usage
1.17. check_blocklist usage
1.18. check_allowlist usage
1.19. userblocklist.reload_blocklist usage
1.20. reload_blocklist usage
1.21. dump_blocklist usage
1.22. check_blocklist usage
1.23. check_allowlist usage
1.24. check_userblocklist usage
1.25. check_userallowlist usage
1.26. Example database content - globalblocklist table
1.27. Example database content - userblocklist table

Chapter 1. Admin Guide

1. Overview

The userblocklist module allows Kamailio to handle blocklists 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 blocklisted or not.

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

The module exports four functions, check_blocklist, check_allowlist, check_user_blocklist and check_user_allowlist for usage in the configuration file. Furthermore it provides a MI function to reload the global blocklist 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 db_* 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. Parameters

3.1. use_domain (integer)

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

Default value is 0.

Example 1.1. Set use_domain parameter

...
modparam("userblocklist", "use_domain", 1)
...

3.2. match_mode (integer)

The number of individual characters that are used for matching. Valid values are 10 or 128. When you specify 10, only digits will be used for matching, this operation mode is equivalent to the old behaviour. When configured with 128, all standard ASCII chars are available for matching. Please be aware that memory requirements for storing the routing tree in shared memory will also increase by a factor of 12.8.

Default value is 10.

Example 1.2. Set match_mode parameter

...
modparam("userblocklist", "match_mode", 128)
...

3.3. db_url (String)

URL to the database containing the data.

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

Example 1.3. Set db_url parameter

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

3.4. userblocklist_table (String)

Name of the userblocklist table for the userblocklist module.

Default value is userblocklist.

Example 1.4. Set userblocklist_table parameter

...
modparam("userblocklist", "userblocklist_table", "userblocklist")
...

3.5. userblocklist_id_col (string)

unique ID

Example 1.5. Set userblocklist_id_col parameter

...
modparam("userblocklist", "userblocklist_id_col", "id")
...

3.6. userblocklist_username_col (string)

The user that is used for the blocklist lookup.

Example 1.6. Set userblocklist_username_col parameter

...
modparam("userblocklist", "userblocklist_username_col", "username")
...

3.7. userblocklist_domain_col (string)

The domain that is used for the blocklist lookup.

Example 1.7. Set userblocklist_domain_col parameter

...
modparam("userblocklist", "userblocklist_domain_col", "domain")
...

3.8. userblocklist_prefix_col (string)

The prefix that is matched for the blocklist.

Example 1.8. Set userblocklist_prefix_col parameter

...
modparam("userblocklist", "userblocklist_prefix_col", "prefix")
...

3.9. userblocklist_allowlist_col (string)

Specify if this a blocklist (0) or a allowlist (1) entry.

Example 1.9. Set userblocklist_allowlist_col parameter

...
modparam("userblocklist", "userblocklist_allowlist_col", "allowlist")
...

3.10. globalblocklist_table (String)

Name of the globalblocklist table for the userblocklist module. Please note that this table is used when the check_blocklist function is called with no parameters.

Default value is globalblocklist.

Example 1.10. Set globalblocklist_table parameter

...
modparam("userblocklist", "globalblocklist_table", "globalblocklist")
...

3.11. globalblocklist_id_col (string)

unique ID

Example 1.11. Set globalblocklist_id_col parameter

...
modparam("userblocklist", "globalblocklist_id_col", "id")
...

3.12. globalblocklist_prefix_col (string)

The prefix that is matched for the blocklist.

Example 1.12. Set globalblocklist_prefix_col parameter

...
modparam("userblocklist", "globalblocklist_prefix_col", "prefix")
...

3.13. globalblocklist_allowlist_col (string)

Specify if this a blocklist (0) or a allowlist (1) entry.

Example 1.13. Set globalblocklist_allowlist_col parameter

...
modparam("userblocklist", "globalblocklist_allowlist_col", "allowlist")
...

3.14. globalblocklist_description_col (string)

A comment for the entry.

Example 1.14. Set globalblocklist_description_col parameter

...
modparam("userblocklist", "globalblocklist_description_col", "description")
...

4. Functions

4.1.  check_user_blocklist (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 allowlist, 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 omitted. The number parameter can be used to check for example against the from URI user.

Example 1.15. check_user_blocklist usage

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

4.2.  check_user_allowlist (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 allowlist, 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 omitted. The number parameter can be used to check for example against the from URI user.

Example 1.16. check_user_allowlist usage

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

4.3.  check_blocklist ([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 allowlist, false is returned. Otherwise, true is returned. If no table is given, then globalblocklist_table is used.

Example 1.17. check_blocklist usage

...
if (!check_blocklist("globalblocklist")) {
	sl_send_reply("403", "Forbidden");
	exit;
}
...

4.4.  check_allowlist (string table)

Finds the longest prefix that matches the request URI for the given table. If a match is found and it is set to allowlist, true is returned. Otherwise, false is returned.

Example 1.18. check_allowlist usage

...
if (!check_allowlist("globalblocklist")) {
	sl_send_reply("403", "Forbidden");
	exit;
}
...

5. RPC Commands

5.1.  userblocklist.reload_blocklist

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

Example 1.19. userblocklist.reload_blocklist usage

...
kamcmd userblocklist.reload_blocklist
...

6. MI Commands

6.1.  reload_blocklist

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

Example 1.20. reload_blocklist usage

					...
					kamctl fifo reload_blocklist
					...

6.2.  dump_blocklist

Dumps the default, in memory, global_blocklist content to stdout. Note that a reload_blocklist should be issued before, in order to see the latest content of the database.

Example 1.21. dump_blocklist usage

					...
					kamctl fifo reload_blocklist
					kamctl fifo dump_blocklist
					...

6.3.  check_blocklist prefix

Searches in the default, in memory, global list. Finds the longest prefix that matches the given prefix parameter. Returns true if the prefix is found and the allowlist is not set. Returns false otherwise - either prefix found and allowlist set or prefix not found. Note that a reload_blocklist should be issued before, in order to check through the latest content of the database.

Example 1.22. check_blocklist usage

					...
					kamctl fifo reload_blocklist
					kamctl fifo check_blocklist prefix
					...

6.4.  check_allowlist prefix

Searches in the default, in memory, global list. Finds the longest prefix that matches the given prefix parameter. Returns true if the prefix is found and the allowlist is set. Returns false otherwise - either prefix found and allowlist not set or prefix not found. Note that a reload_blocklist should be issued before, in order to check through the latest content of the database.

Example 1.23. check_allowlist usage

					...
					kamctl fifo reload_blocklist
					kamctl fifo check_allowlist prefix
					...

6.5.  check_userblocklist user [domain] prefix

Searches in the default user list table. Finds the longest prefix for the given user@domain that matches the given prefix parameter. Returns true if the prefix is found and the allowlist is not set. Returns false otherwise - either prefix found and allowlist set or prefix not found. Note that the domain parameter is optional. If not given, the second parameter is the considered to be the prefix.

Example 1.24. check_userblocklist usage

					...
					kamctl fifo check_userblocklist user [domain] prefix
					...

6.6.  check_userallowlist user [domain] prefix

Searches in the default user list table. Finds the longest prefix for the given user@domain that matches the given prefix parameter. Returns true if the prefix is found and the allowlist is set. Returns false otherwise - either prefix found and allowlist not set or prefix not found. Note that the domain parameter is optional. If not given, the second parameter is the considered to be the prefix.

Example 1.25. check_userallowlist usage

					...
					kamctl fifo check_userallowlist user [domain] prefix
					...

7. Installation and Running

7.1. Database setup

Before running Kamailio with the userblocklist module, you have to setup the database table where the module will read the blocklist 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 userblocklist-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, https://www.kamailio.org/docs/db-tables/kamailio-db-devel.html.

Example 1.26. Example database content - globalblocklist table

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

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

Example 1.27. Example database content - userblocklist table

...
+----+----------------+-------------+-----------+-----------+
| id | username       | domain      | prefix    | allowlist |
+----+----------------+-------------+-----------+-----------+
| 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 blocklists 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.