# &adminguide;

## Overview

The Permissions module provides functions for handling IP based access control lists (ACL) in a number of ways.

- Call Routing

- Registration permissions

- URI permissions

- Address permissions

- Trusted Requests

The Address permissions and Trusted request handling supports using a database to load ACLs into RAM for fast processing.

### Call Routing

The module can be used to determine if a call has appropriate permission to be established. Permission rules are stored in plaintext configuration files similar to `hosts.allow` and `hosts.deny` files used by tcpd.

When `allow_routing` function is called it tries to find a rule that matches selected fields of the message.

&kamailio; is a forking proxy and therefore a single message can be sent to different destinations simultaneously. When checking permissions all the destinations must be checked and if one of them fails, the forwarding will fail.

The matching algorithm is as follows, first match wins:

- Create a set of pairs of form (From, R-URI of branch 1), (From, R-URI of branch 2), etc.

- Routing will be allowed when all pairs match an entry in the allow file.

- Otherwise routing will be denied when one of pairs matches an entry in the deny file.

- Otherwise, routing will be allowed.

A non-existing permission control file is treated as if it were an empty file. Thus, permission control can be turned off by providing no permission control files.

From header field and Request-URIs are always compared with regular expressions! For the syntax see the sample file: `config/permissions.allow`.

### Registration Permissions

In addition to call routing it is also possible to check REGISTER messages and decide--based on the configuration files--whether the message should be allowed and the registration accepted or not.

Main purpose of the function is to prevent registration of "prohibited" IP addresses. One example, when a malicious user registers a contact containing IP address of a PSTN gateway, he might be able to bypass authorization checks performed by the SIP proxy. That is undesirable and therefore attempts to register IP address of a PSTN gateway should be rejected. Files `config/register.allow` and `config/register.deny` contain an example configuration.

The function for registration checking is called `allow_register` and the algorithm is very similar to the algorithm described in . The only difference is in the way how pairs are created. Additionally one can use `allow_register_include_port` function in order to include the port value of the Contact into the check.

Instead of the From header field the function uses the To header field because the To header field in REGISTER messages contains the URI of the person being registered. Instead of the Request-URI of branches the function uses the Contact header field.

Thus, the pairs used in matching will look like this: (To, Contact 1), (To, Contact 2), (To, Contact 3), and so on..

The algorithm of matching is the same as described in .

### URI Permissions

The module can be used to determine if a request to a destination is allowed, based on an URI stored in a pvar. Permission rules are stored in plaintext configuration files similar to `hosts.allow` and `hosts.deny` used by tcpd.

When the `allow_uri` function is called, it tries to find a rule that matches selected fields of the message. The matching algorithm is as follows, where the first match wins:

- Create a pair <From URI, URI stored in pvar>.

- Request will be allowed when the pair matches an entry in the allow file.

- Request will be denied when the pair matches an entry in the deny file.

- Otherwise, request will be allowed.

A non-existing permission control file is treated as if it were an empty file. Thus, permission control can be turned off by providing no permission control files.

The From URI and the URI stored in pvar are always compared with regular expressions! For the syntax see the sample file: `config/permissions.allow`.

### Address Permissions

The module can be used to determine if an address (IP address and port or DNS domain name) matches any of the addresses stored in a cached &kamailio; database table or file. IP addresses in the database table or file can be subnet addresses. Port 0 matches any port. The address and port to be matched can be either taken from the source of IP packet of the request (allow_source_address) or given as a variable argument (allow_address).

Addresses stored in the database table or file can be grouped together into one or more groups specified by a group identifier (positive integer value, i.e., equal or greater than 1). The group identifier is given as an argument to the allow_address() and allow_source_address() functions. One group can contain all of the three types of addresses: exact IP address, subnet IP address or DNS domain name.

When the argument is an IP address, it is tried to be matched with the records from that group that are of type exact IP or subnet. If the argument is not an IP it is tried to be matched with the records that are DNS domain names. No DNS lookup is performed, only strict matching.

As a side effect of matching the address, non-NULL tag (see tag_col module parameter) is added as value to peer_tag AVP if peer_tag_avp module parameter has been defined.

Starting with Kamailio version 6.1.x, the `allow_address()` its related functions can do First Prefix Match (FPM) or the Longest Prefix Match (LPM) methods to find the subnet matching record, which can set the tag variable. The matching method is controled by the parameter subnet_match_mode.

Th LPM means the `_group` variants will now return the most specific (longest) subnet match, instead of the first match (which was previously the entry with the lowest group ID). The FPM/LPM behavior is now consistent across the following functions:

- `allow_address()`

- `allow_source_address()`

- `allow_source_address_group()`

- `allow_address_group()`

### Trusted Requests

The module can be used to determine if an incoming request can be trusted without authentication.

When the `allow_trusted` function is called, it tries to find a rule that matches the request. Rules contain the following fields: <source address, transport protocol, regular expression>.

A request is accepted if there exists a rule, where

- source address is equal to the source address of the request or the source address given in pvar,

- transport protocol is either "ANY" or equal to the transport protocol of request or the transport protocol given in pvar, and

- regular expression is either empty (NULL in database) or matches the request's From (or optionally provided) URI.

Otherwise the request is rejected.

As a side effect of accepting the request, the peer's non-NULL tag (see tag_col module parameter) is added as value to peer_tag AVP if the peer_tag_avp module parameter has been defined.

Rules are stored in a database table specified by the module parameters. There is a module parameter called `db_mode` that determines if the rules are cached into memory for faster matching or if the database is consulted for each invocation of the allow_trusted() function call.

## Dependencies

### &kamailio; Modules

The following modules must be loaded before this module:

- No dependencies on other &kamailio; modules.

### External Libraries or Applications

The following libraries or applications must be installed before running &kamailio; with this module loaded:

- None.

## Parameters

### `default_allow_file` (string)

Default allow file used by the functions with no parameters. If you don't specify a full pathname then the directory in which the main config file is located will be used.

Default value is permissions.allow.

#### Set `default_allow_file` parameter

    ...
    modparam("permissions", "default_allow_file", "/etc/permissions.allow")
    ...

### `default_deny_file` (string)

Default file containing deny rules. The file is used by functions with no parameters. If you don't specify a full pathname then the directory in which the main config file is located will be used.

Default value is permissions.deny.

#### Set `default_deny_file` parameter

    ...
    modparam("permissions", "default_deny_file", "/etc/permissions.deny")
    ...

### `check_all_branches` (integer)

If set then allow_routing functions will check Request-URI of all branches (default). If disabled then only Request-URI of the first branch will be checked.

Do not disable this parameter unless you really know what you are doing.

Default value is 1.

#### Set `check_all_branches` parameter

    ...
    modparam("permissions", "check_all_branches", 0)
    ...

### `allow_suffix` (string)

Suffix to be appended to basename to create filename of the allow file when version with one parameter of either `allow_routing` or `allow_register_include_port` or `allow_register` is used.

Including leading dot.

Default value is .allow.

#### Set `allow_suffix` parameter

    ...
    modparam("permissions", "allow_suffix", ".allow")
    ...

### `deny_suffix` (string)

Suffix to be appended to basename to create filename of the deny file when version with one parameter of either `allow_routing` or `allow_register_include_port` or `allow_register` is used.

Including leading dot.

Default value is .deny.

#### Set `deny_suffix` parameter

    ...
    modparam("permissions", "deny_suffix", ".deny")
    ...

### `address_file` (string)

This is the name of full path to the file that store rules used by `allow_address` function (and its variants). If it is only the file name, it is expected to be in the same folder as &kamailioconfig; file.

If set, this parameter has priority over the database backend, so the address matching records are loaded from the file, not from database.

To see the format of the file see the section "Address File Format".

Default value is NULL.

#### Set `address_file` parameter

    ...
    modparam("permissions", "address_file", "address.list")
    ...

### `db_url` (string)

This is URL of the database to be used to store rules used by `allow_trusted` or `allow_address` functions.

Default value is NULL.

#### Set `db_url` parameter

    ...
    modparam("permissions", "db_url", "&exampledb;")
    ...

### `address_table` (string)

The name of the database table containing IP subnets and DNS domain names used by `allow_address` and `allow_source_address` functions.

Default value is address.

#### Set `address_table` parameter

    ...
    modparam("permissions", "address_table", "addr")
    ...

### `grp_col` (string)

Name of address table column containing the group identifier of the address.

Default value is grp.

#### Set `grp_col` parameter

    ...
    modparam("permissions", "grp_col", "group_id")
    ...

### `ip_addr_col` (string)

Name of address table column containing the IP address part of the address.

Default value is ip_addr.

#### Set `ip_addr_col` parameter

    ...
    modparam("permissions", "ip_addr_col", "ip_address")
    ...

### `mask_col` (string)

Name of address table column containing the network mask of the address. Possible values are 0-32 for IPv4 and 0-128 for IPv6 addresses. If the value is 0, the network mask is set to 32 for IPv4 addresses and to 128 for IPv6 addresses.

Default value is mask.

#### Set `mask_col` parameter

    ...
    modparam("permissions", "mask_col", "subnet_length")
    ...

### `port_col` (string)

Name of address table column containing the port part of the address.

Default value is port.

#### Set `port_col` parameter

    ...
    modparam("permissions", "port_col", "port")
    ...

### `db_mode` (integer)

Database mode. 0 means non-caching, 1 means caching. Valid only for the `allow_trusted` function.

Default value is 0 (non-caching).

#### Set `db_mode` parameter

    ...
    modparam("permissions", "db_mode", 1)
    ...

### `trusted_table` (string)

Name of database table containing the matching rules used by the `allow_trusted` function.

Default value is trusted.

#### Set `trusted_table` parameter

    ...
    modparam("permissions", "trusted_table", "pbx")
    ...

### `source_col` (string)

Name of column in the trusted table containing the source IP address that is matched against source IP address of received request.

Default value is src_ip.

#### Set `source_col` parameter

    ...
    modparam("permissions", "source_col", "source_ip_address")
    ...

### `proto_col` (string)

Name of column in the trusted table containing the transport protocol that is matched against transport protocol of the received request. Possible values that can be stored in proto_col are any, udp, tcp, tls, sctp, ws, wss, and none. Value any matches always and value none never.

Default value is proto.

#### Set `proto_col` parameter

    ...
    modparam("permissions", "proto_col", "transport")
    ...

### `from_col` (string)

Name of the column trusted table containing a regular expression that is matched against the From URI.

Default value is from_pattern.

#### Set `from_col` parameter

    ...
    modparam("permissions", "from_col", "regexp")
    ...

### `ruri_col` (string)

Name of the column trusted table containing a regular expression that is matched against the Request URI.

Default value is ruri_pattern.

#### Set `ruri_col` parameter

    ...
    modparam("permissions", "ruri_col", "regexp")
    ...

### `tag_col` (string)

Name of the column in the address or trusted table containing a string that is added as value to peer_tag AVP if peer_tag AVP has been defined and if the address or peer matches.

The tag_col field will be implicitly converted to a string when the database field is loaded into peer_tag AVP if the field type is supported.

Default value is tag.

#### Set `tag_col` parameter

    ...
    modparam("permissions", "tag_col", "peer_tag")
    ...

### `priority_col` (string)

The column name used to store the priority of the corresponding rule from the database row. Priority values should be integer. When db_mode is set to 1 (caching), priorities are ordered from highest to lowest. In non-caching mode, priority order (ASC vs DESC) is determined by database.

Default value is priority.

#### Set `priority_col` parameter

    ...
    modparam("permissions", "priority_col", "column_name")
    ...

### `peer_tag_avp` (AVP string)

If defined, the AVP will be set as a side effect of `allow_trusted` call to not NULL tag column value of the matching peer.

Default value is undefined.

#### Set `peer_tag_avp` parameter

    ...
    modparam("permissions", "peer_tag_avp", "$avp(i:707)")
    ...

### `peer_tag_mode` (integer)

Tag mode for `allow_trusted`. 0 sets only the tag of the first match. 1 adds the tags of all matches to the avp. In addition the return value of `allow_trusted` is the number of matches. This parameter is not used for address table matching functions.

Default value is 0.

#### Set `peer_tag_mode` parameter

    ...
    modparam("permissions", "peer_tag_mode", 1)
    ...

### `max_subnets` (int)

The maximum number of subnet addresses to be loaded from address table.

Default value is 512.

#### Set `max_subnets` parameter

    ...
    modparam("permissions", "max_subnets", 1024)
    ...

### `subnet_match_mode` (int)

Control how subnet addresses are matched: 0 - return on the first prefix match; 1 - return on the longest prefix match. It impacts functions like allow_source_address(), allow_address(), allow_source_address_group() or allow_address_group().

Default value is 0.

#### Set `subnet_match_mode` parameter

    ...
    modparam("permissions", "subnet_match_mode", 1)
    ...

### `load_backends` (int)

Control what backends should be loaded: 1 - address table; 2 - trusted table; 4 - allow file; 8 - deny file.

It can be a combination (sum) of the options to load many backends (e.g., 3 - loads address and trusted tables).

Default value is 0xffff (load all backends).

#### Set `load_backends` parameter

    ...
    modparam("permissions", "load_backends", 1)
    ...

### `reload_delta` (int)

The number of seconds that have to be waited before executing a new RPC reload. By default there is a rate limiting of maximum one reload in five seconds.

If set to 0, no rate limit is configured. Note carefully: use this configuration only in tests environments because executing two RPC reloads of the same table at the same time can cause &kamailio; to crash.

Default value is 5.

#### Set `reload_delta` parameter

    ...
    modparam("permissions", "reload_delta", 1)
    ...

### `trusted_cleanup_interval` (int)

If module parameter `db_mode` is set to 1 a cleanup timer is set to the trusted_cleanup_interval value in seconds. This process will cleanup the previous values from memory after a RPC reload.

Default value is 60.

#### Set `trusted_cleanup_interval` parameter

    ...
    modparam("permissions", "trusted_cleanup_interval", 120)
    ...

## Functions

### `allow_routing()`

Returns true if all pairs constructed as described in have appropriate permissions according to the configuration files. This function uses default configuration files specified in `default_allow_file` and `default_deny_file`.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

#### `allow_routing` usage

    ...
    if (allow_routing()) {
    	t_relay();
    };
    ...

### `allow_routing(basename)`

Returns true if all pairs constructed as described in have appropriate permissions according to the configuration files given as parameters.

Meaning of the parameters is as follows:

- basename - Basename from which allow and deny filenames will be created by appending contents of `allow_suffix` and `deny_suffix` parameters.

  If the parameter doesn't contain full pathname then the function expects the file to be located in the same directory as the main configuration file of the server.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

#### `allow_routing(basename)` usage

    ...
    if (allow_routing("basename")) {
    	t_relay();
    };
    ...

### `allow_routing(allow_file, deny_file)`

Returns true if all pairs constructed as described in have appropriate permissions according to the configuration files given as parameters.

Meaning of the parameters is as follows:

- allow_file - File containing allow rules.

  If the parameter doesn't contain full pathname then the function expects the file to be located in the same directory as the main configuration file of the server.

- deny_file - File containing deny rules.

  If the parameter doesn't contain full pathname then the function expects the file to be located in the same directory as the main configuration file of the server.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

#### `allow_routing(allow_file, deny_file)` usage

    ...
    if (allow_routing("rules.allow", "rules.deny")) {
    	t_relay();
    };
    ...

### `allow_register(basename)`

The function returns true if all pairs constructed as described in have appropriate permissions according to the configuration files given as parameters.

Meaning of the parameters is as follows:

- basename - Basename from which allow and deny filenames will be created by appending contents of `allow_suffix` and `deny_suffix` parameters.

  If the parameter doesn't contain full pathname then the function expects the file to be located in the same directory as the main configuration file of the server.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

#### `allow_register(basename)` usage

    ...
    if (method=="REGISTER") {
    	if (allow_register("register")) {
    		save("location");
    		exit;
    	} else {
    		sl_send_reply("403", "Forbidden");
    	};
    };
    ...

### `allow_register(allow_file, deny_file)`

The function returns true if all pairs constructed as described in have appropriate permissions according to the configuration files given as parameters.

Meaning of the parameters is as follows:

- allow_file - File containing allow rules.

  If the parameter doesn't contain full pathname then the function expects the file to be located in the same directory as the main configuration file of the server.

- deny_file - File containing deny rules.

  If the parameter doesn't contain full pathname then the function expects the file to be located in the same directory as the main configuration file of the server.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

#### `allow_register(allow_file, deny_file)` usage

    ...
    if (method=="REGISTER") {
    	if (allow_register("register.allow", "register.deny")) {
    		save("location");
    		exit;
    	} else {
    		sl_send_reply("403", "Forbidden");
    	};
    };
    ...

### `allow_register_include_port(basename)`

The function does exacty the same thing as `allow_register(basename)` apart that it tells the module to include the port value of Contact into the check. No additional function parameters required.

Meaning of the parameters is as follows:

- basename - Basename from which allow and deny filenames will be created by appending contents of `allow_suffix` and `deny_suffix` parameters.

  If the parameter doesn't contain full pathname then the function expects the file to be located in the same directory as the main configuration file of the server.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

#### `allow_register_include_port(basename)` usage

    ...
    if (method=="REGISTER") {
    	if (allow_register_include_port("register")) {
    		save("location");
    		exit;
    	} else {
    		sl_send_reply("403", "Forbidden");
    	};
    };
    ...

### `allow_register_include_port(allow_file, deny_file)`

The function does exacty the same thing as `allow_register(allow_file, deny_file)` apart that it tells the module to include the port value of Contact into the check. No additional function parameters required.

Meaning of the parameters is as follows:

- allow_file - File containing allow rules.

  If the parameter doesn't contain full pathname then the function expects the file to be located in the same directory as the main configuration file of the server.

- deny_file - File containing deny rules.

  If the parameter doesn't contain full pathname then the function expects the file to be located in the same directory as the main configuration file of the server.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

#### `allow_register_include_port(allow_file, deny_file)` usage

    ...
    if (method=="REGISTER") {
    	if (allow_register_include_port("register.allow", "register.deny")) {
    		save("location");
    		exit;
    	} else {
    		sl_send_reply("403", "Forbidden");
    	};
    };
    ...

### `allow_uri(basename, pvar)`

Returns true if the pair constructed as described in have appropriate permissions according to the configuration files specified by the parameter.

Meaning of the parameter is as follows:

- basename - Basename from which allow and deny filenames will be created by appending contents of `allow_suffix` and `deny_suffix` parameters.

  If the parameter doesn't contain full pathname then the function expects the file to be located in the same directory as the main configuration file of the server.

- pvar - Any pseudo-variable defined in &kamailio;.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

#### `allow_uri(basename, pvar)` usage

    ...
    if (allow_uri("basename", "$rt")) {  // Check Refer-To URI
    	t_relay();
    };
    if (allow_uri("basename", "$avp(i:705)") {  // Check URI stored in $avp(i:705)
    	t_relay();
    };
    ...

### `allow_address(group_id, ip_addr_pvar, port_pvar)`

Returns true if the address and port given as values of pvar arguments belonging to a group given as group_id argument matches an IP subnet or a DNS domain name found in cached address table.

When matching is done if the argument is an IP address, it is matched with the records from that group that are of type exact IP or subnet. If the argument is not an IP it is tried to be matched with the records that are DNS domain names. No DNS lookup is performed, only strict matching. Cached address table entry containing port value 0 matches any port. The group_id argument can be an integer string or a pseudo variable.

See Address permissions for more details.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

#### `allow_address()` usage

    ...

    // Check if source address/port is in group 1
    if (!allow_address("1", "$si", "$sp")) {
    	sl_send_reply("403", "Forbidden");
    };
    // Check address/port stored in AVPs src_adr/src_port is in group 2
    $avp(dst_adr) = "sipdomain.com";
    $avp(dst_port) = "0";
    if (!allow_address("2", "$avp(dst_adr)", "$avp(dst_port)") {
    	sl_send_reply("403", "Forbidden");
    };
    ...

### `allow_source_address([group_id])`

Equal to allow_address(group_id, "$si", "$sp"). If 'group_id' is missing, the function is equal to allow_address("1", "$si", "$sp").

See Address permissions for more details.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

#### `allow_source_address(group_id)` usage

    ...

    // Check source address/port of request
    if (!allow_source_address("1")) {
    	sl_send_reply("403", "Forbidden");
    };
    ...

### `allow_source_address_group()`

Checks if source address/port is found in cached address or subnet table in any group. If yes, returns that group. If not returns -1. Port value 0 in cached address and group table matches any port.

See Address permissions for more details on how searching is implemented.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

#### `allow_source_address_group()` usage

    ...

    $var(group) = allow_source_address_group();
    if ($var(group) != -1) {
       # do something with $var(group)
    };
    ...

### `allow_address_group(addr, port)`

Checks if address/port is found in cached address or subnet table in any group. If yes, returns that group. If not returns -1. Port value 0 in cached address and group table matches any port. The parameters can be pseudo-variables.

See Address permissions for more details on how searching is implemented.

This function can be used from ANY_ROUTE.

#### `allow_source_address_group()` usage

    ...

    $var(group) = allow_address_group("1.2.3.4", "5060");
    if ($var(group) != -1) {
       # do something with $var(group)
    };
    ...

### `allow_trusted([src_ip_pvar, proto_pvar, furi_pvar])`

Checks based either on request's source address and transport protocol or source address and transport protocol given in pvar arguments, and From URI of request (or furi_pvar if provided) if request can be trusted without authentication. Returns 1 if a match is found as described in and -1 otherwise. If a match is found and `peer_tag_avp` has been defined, adds a non-NULL tag column value of the matching peer to AVP peer_tag_avp.

NOTE: source IP is matched using string comparison. Be careful if the IP can have different forms, for a safer alternative for matching IP addresses, look at allow_source_address or allow_address().

Source address, transport protocol and uri given in the arguments must be in string format and they can contain script variables. Valid transport protocol values are (ignoring case) "any", "udp, "tcp", "tls", "ws", "wss" and "sctp".

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

#### `allow_trusted()` usage

    ...
    if (allow_trusted()) {
    	t_relay();
    }
    ...
    if (allow_trusted("$si", "$proto")) {
    	t_relay();
    }
    ...
    if (allow_trusted("$si", "any", "$ai")) {
    	t_relay();
    }
    ...

## RPC Commands

### `permissions.addressReload`

Causes the permissions module to re-read the contents of address database table into cache memory. In cache memory the entries are for performance reasons stored in two different tables: address table and subnet table depending on the value of the mask field (IPv6: 64 or smaller, IPv4: 32 or smaller). Note that there is a rate limiting defined by 'reload_delta' parameter. By default is allowed maximum one reload in five seconds.

Parameters: none

This RPC command is exported with "RPC_EXEC_DELTA" flag, therefore its execution rate can be restricted to specific time intervals by setting the "rpc_exec_delta" core parameter.

### `permissions.addressDump`

Causes the permissions module to dump the contents of cache memory address table. (Not the subnet table).

Parameters: none

### `permissions.subnetDump`

Causes permissions module to dump contents of cache memory subnet table.

Parameters: none

### `permissions.domainDump`

Causes permissions module to dump contents of cache memory domain table.

Parameters: none

### `permissions.testUri`

Tests if the (URI, Contact) pair is allowed according to allow/deny files. The files must already have been loaded by &kamailio;.

Parameters:

- basename - Basename from which allow and deny filenames will be created by appending contents of the allow_suffix and deny_suffix parameters.

- URI - URI to be tested

- Contact - Contact to be tested

### `permissions.allowUri`

### `permissions.trustedReload`

Causes the permissions module to re-read the contents of the trusted database table into cache memory. Note that there is a rate limiting defined by 'reload_delta' parameter. By default is allowed maximum one reload in five seconds.

Parameters: none

This RPC command is exported with "RPC_EXEC_DELTA" flag, therefore its execution rate can be restricted to specific time intervals by setting the "rpc_exec_delta" core parameter.

### `permissions.trustedDump`

Causes the permissions module to dump contents of the trusted database table from cache memory.

Parameters: none

## Address File Format

It is a text file with one record per line. Lines starting with '#' are considered comments and ignored. Comments can be also at the end of records, by using '#' to start the comment part of the line.

Each record line has the format:

    ...
    (groupid,int) (address,str) (netmask,int,o), (port,int,o) (tag,str,o)
    ...

The groupid, address, netmask, port and tag are the names of the attributes whose values are expected in the respective order. The 'int' indicates that the value has to be an integer number. The 'str' indicates that the value has to be a string. The 'o' indicates that the attribute is optional. If netmask is not provided, it is set to 32 for IPv4 addresses and 128 for IPv6 addresses. If port is not provided, it is set to 0. The tag attribute is not set, if not provided. When provided, the tag value has to be a single token, without whitespaces (other punctuation signs can be in its value, like ',', '=', ';', ...).

### Address File Sample

    ...
    # address file - records to match with allow_address(...) and variants
    # * file format details
    #   - comments start with # and go to end of line
    #   - each line corresponds to a record with following attributes:
    #
    #     (groupid,int) (address,str) (netmask,int,o), (port,int,o) (tag,str,o)
    #
    # * description of the tokens used to describe line format
    #   - int: expected integer value
    #   - str: expected string value
    #   - o: optional field

    1 127.0.0.1 32 0 tag1
    1 10.0.0.10

    2 192.168.1.0 24 0 tag2
    2 192.168.2.0 24 0 tag3

    3 [1:5ee::900d:c0de]
    ...

## Register File Format

It is a text file with one record per line. Lines starting with '#' are considered comments and ignored. Comments can be also at the end of records, by using '#' to start the comment part of the line.

Each record line has the format:

    ...
    (from_list,str) (req_uri_list,str)
    ...

The 'str' indicates that the value has to be a string compatible with POSIX Extended Regular Expressions.

### Register File Sample

    ...
    # Syntax:
    #	from_list [EXCEPT from_list] : req_uri_list [EXCEPT req_uri_list]
    #
    # 	from_list and req_uri_list are comma separated expressions
    # 	Expressions are treated as case insensitive POSIX Extended Regular Expressions.
    # 	Keyword ALL matches any expression.
    #
    # Examples (requires a usage of allow_register() function):
    #	ALL : "^sip:361[0-9]*@abc\.com$" EXCEPT "^sip:361[0-9]*3@abc\.com$", "^sip:361[0-9]*4@abc\.com$"
    #
    #	"^sip:3677[0-9]*@abc\.com$" :  "^sip:361[0-9]*@abc\.com$"
    #
    #	All : ALL
    #
    # Examples including port check (requires a usage of allow_register_include_port() function):
    #
    # ALL : "^sip:.*@192.168.0.1:5062"
    ...