PERMISSIONS module
Admin Guide
Section titled “Admin Guide”Overview
Section titled “Overview”Call Routing
Section titled “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.
OpenSIPS 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
Section titled “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.
Function for registration checking is called allow_register and the algorithm is very
similar to the algorithm described in
sec call routing. The only difference is in the way
how pairs are created.
Instead of From header field the function uses To header field because To header field in REGISTER messages contains the URI of the person being registered. Instead of the Request-URI of branches the function uses Contact header field.
Thus, 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 same as described in sec call routing.
URI Permissions
Section titled “URI Permissions”The module can be used to determine if request is
allowed to the destination specified by 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 allow_uri
function is called, it tries to find a rule that matches
selected fields of the message.
The matching algorithm is as follows, 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.
- Otherwise 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.
From URI and URI stored in pvar are always compared with regular
expressions! For the syntax see the sample file:
config/permissions.allow.
Address Permissions
Section titled “Address Permissions”The module can be used to determine if an address (IP address and port) matches any of the IP subnets stored in cached OpenSIPS database table. Port 0 in cached database table matches any port. IP address and port to be matched can be either taken from the request (allow_source_address) or given as pvar arguments (allow_address).
Addresses stored in cached database table can be grouped together into one or more groups specified by a group identifier (unsigned integer). Group identifier is given as argument to allow_address and allow_source_address functions.
Trusted Requests
Section titled “Trusted Requests”The module can be used to determine if an incoming request can be trusted without authentication.
When 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 requests is accepted if there exists a rule, where
- source address is equal to source address of request or source address given in pvar,
- transport protocol is either “ANY” or equal to transport protocol of request or transport protocol given in pvar, and
- regular expression is either empty (NULL in database) or matches From URI of request.
Otherwise the request is rejected.
Rules are stored in a database table specified by module
parameters. There also exists a module parameter
dm_mode that
determines if rules are cached into memory for faster
matching or if database is consulted for each invocation
of allow_trusted function call.
Dependencies
Section titled “Dependencies”OpenSIPS Modules
Section titled “OpenSIPS Modules”The following modules must be loaded before this module:
- No dependencies on other OpenSIPS modules.
External Libraries or Applications
Section titled “External Libraries or Applications”The following libraries or applications must be installed before running OpenSIPS with this module loaded:
- None.
Exported Parameters
Section titled “Exported Parameters”default_allow_file (string)
Section titled “default_allow_file (string)”Default allow file used by functions without parameters. If you don’t specify full pathname then the directory in which is the main config file is located will be used.
Default value is “permissions.allow”.
...modparam("permissions", "default_allow_file", "/etc/permissions.allow")...default_deny_file (string)
Section titled “default_deny_file (string)”Default file containing deny rules. The file is used by functions without parameters. If you don’t specify full pathname then the directory in which the main config file is located will be used.
Default value is “permissions.deny”.
...modparam("permissions", "default_deny_file", "/etc/permissions.deny")...check_all_branches (integer)
Section titled “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.
Default value is 1.
...modparam("permissions", "check_all_branches", 0)...allow_suffix (string)
Section titled “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 is used.
Default value is “.allow”.
...modparam("permissions", "allow_suffix", ".allow")...deny_suffix (string)
Section titled “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 is used.
Default value is “.deny”.
...modparam("permissions", "deny_suffix", ".deny")...db_url (string)
Section titled “db_url (string)”This is URL of the database to be used to store rules used by
allow_trusted function.
Default value is “NULL”.
...modparam("permissions", "db_url", "dbdriver://username:password@dbhost/dbname")...address_table (string)
Section titled “address_table (string)”Name of database table containing IP subnet information used by
allow_address and
allow_source_address
functions.
Default value is “address”.
...modparam("permissions", "address_table", "addr")...grp_col (string)
Section titled “grp_col (string)”Name of address table column containing group identifier of the address.
Default value is “grp”.
...modparam("permissions", "grp_col", "group_id")...ip_addr_col (string)
Section titled “ip_addr_col (string)”Name of address table column containing IP address part of the address.
Default value is “ip_addr”.
...modparam("permissions", "ip_addr_col", "ip_address")...mask_col (string)
Section titled “mask_col (string)”Name of address table column containing network mask of the address. Possible values are 0-32.
Default value is “mask”.
...modparam("permissions", "mask_col", "subnet_length")...port_col (string)
Section titled “port_col (string)”Name of address table column containing port part of the address.
Default value is “port”.
...modparam("permissions", "port_col", "prt")...db_mode (integer)
Section titled “db_mode (integer)”Database mode. 0 means non-caching, 1 means caching. Valid only for allow_trusted function.
Default value is 0 (non-caching).
...modparam("permissions", "db_mode", 1)...trusted_table (string)
Section titled “trusted_table (string)”Name of database table containing matching rules used by
allow_register function.
Default value is “trusted”.
...modparam("permissions", "trusted_table", "pbx")...source_col (string)
Section titled “source_col (string)”Name of trusted table column containing source IP address that is matched against source IP address of received request.
Default value is “src_ip”.
...modparam("permissions", "source_col", "source_ip_address")...proto_col (string)
Section titled “proto_col (string)”Name of trusted table column containing transport protocol that is matched against transport protocol of received request. Possible values that can be stored in proto_col are “any”, “udp”, “tcp”, “tls”, “sctp”, and “none”. Value “any” matches always and value “none” never.
Default value is “proto”.
...modparam("permissions", "proto_col", "transport")...from_col (string)
Section titled “from_col (string)”Name of trusted table column containing regular expression that is matched against From URI.
Default value is “from_pattern”.
...modparam("permissions", "from_col", "regexp")...tag_col (string)
Section titled “tag_col (string)”Name of trusted table column containing a string that is added as value to peer_tag AVP if peer_tag AVP has been defined and if the peer matches.
Default value is “tag”.
...modparam("permissions", "tag_col", "peer_tag")...peer_tag_avp (AVP string)
Section titled “peer_tag_avp (AVP string)”If defined, the AVP will be set as side effect of allow_trusted() call to not NULL tag column value of the matching peer.
Default value is “undefined”.
...modparam("permissions", "peer_tag_avp", "$avp(i:707)")...Exported Functions
Section titled “Exported Functions”allow_routing()
Section titled “allow_routing()”Returns true if all pairs constructed as described in sec call routing 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.
...if (allow_routing()) { t_relay();};...allow_routing(basename)
Section titled “allow_routing(basename)”Returns true if all pairs constructed as described in sec call routing 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_suffixanddeny_suffixparameters. 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.
...if (allow_routing("basename")) { t_relay();};...allow_routing(allow_file,deny_file)
Section titled “allow_routing(allow_file,deny_file)”Returns true if all pairs constructed as described in sec call routing 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.
...if (allow_routing("rules.allow", "rules.deny")) { t_relay();};...allow_register(basename)
Section titled “allow_register(basename)”The function returns true if all pairs constructed as described in sec registration permissions 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_suffixanddeny_suffixparameters. 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.
...if (method=="REGISTER") { if (allow_register("register")) { save("location"); exit; } else { sl_send_reply("403", "Forbidden"); };};...allow_register(allow_file, deny_file)
Section titled “allow_register(allow_file, deny_file)”The function returns true if all pairs constructed as described in sec registration permissions 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.
...if (method=="REGISTER") { if (allow_register("register.allow", "register.deny")) { save("location"); exit; } else { sl_send_reply("403", "Forbidden"); };};...allow_uri(basename, pvar)
Section titled “allow_uri(basename, pvar)”Returns true if the pair constructed as described in sec uri permissions 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_suffixanddeny_suffixparameters. 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 OpenSIPS.
This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.
...if (allow_uri("basename", "$rt")) { // Check Refer-To URI t_relay();};if (allow_uri("basename", "$avp(i:705)") { // Check URI stored in $avp(i:705) t_relay();};...allow_address(group_id, ip_addr_pvar, port_pvar)
Section titled “allow_address(group_id, ip_addr_pvar, port_pvar)”Returns true if IP address and port given as values of pvar arguments belonging to a group given as group_id argument matches an IP subnet found in cached address table. Cached address table entry containing port value 0 matches any port. group_id argument can be an integer string or a pseudo variable.
This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.
...
// Check if source address/port is in group 1if (!allow_address("1", "$si", "$sp")) { sl_send_reply("403", "Forbidden");};// Check IP address/port stored in AVPs i:704/i:705 is in group 2if (!allow_address("2", "$avp(i:704)", "$avp(i:705)") { sl_send_reply("403", "Forbidden");};...allow_source_address(group_id)
Section titled “allow_source_address(group_id)”Equal to allow_address(group_id, “$si”, “$sp”).
This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.
...
// Check source address/port of requestif (!allow_source_address("0")) { sl_send_reply("403", "Forbidden");};...allow_source_address_group()
Section titled “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.
This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.
...
$var(group) = allow_source_address_group();if ($var(group) != -1) { # do something with $var(group)};...allow_trusted([src_ip_pvar, proto_pvar])
Section titled “allow_trusted([src_ip_pvar, proto_pvar])”Checks based either on request’s source address and transport protocol or source address and transport protocol given in pvar arguments, and From URI of request if request can be trusted without authentication. Returns 1 if a match is found as described in sec trusted requests and -1 otherwise. If a match is found and peer_tag_avp has been defined, adds a non-NULL tag column value of the matching peer to AVP peer_tag_avp.
Source address and transport protocol given in pvar arguments must be in string format. Valid transport protocol values are “UDP, “TCP”, “TLS”, and “SCTP”. (case insensitive)
This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.
...if (allow_trusted()) { t_relay();};...if (allow_trusted("$si", "$proto")) { t_relay();};...Exported MI Functions
Section titled “Exported MI Functions”address_reload
Section titled “address_reload”Causes 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 (32 or smaller).
Parameters: none
address_dump
Section titled “address_dump”Causes permissions module to dump contents of cache memory address table.
Parameters: none
subnet_dump
Section titled “subnet_dump”Causes permissions module to dump contents of cache memory subnet table.
Parameters: none
trusted_reload
Section titled “trusted_reload”Causes permissions module to re-read the contents of trusted table into cache memory.
Parameters: none
trusted_dump
Section titled “trusted_dump”Causes permissions module to dump contents of trusted table from cache memory.
Parameters: none
allow_uri
Section titled “allow_uri”Tests if (URI, Contact) pair is allowed according to allow/deny files. The files must already have been loaded by OpenSIPS.
Parameters:
- basename - Basename from which allow and deny filenames will be created by appending contents of allow_suffix and deny_suffix parameters.
- URI - URI to be tested
- Contact - Contact to be tested
Contributors
Section titled “Contributors”By Commit Statistics
Section titled “By Commit Statistics”Top contributors by DevScore(1), authored commits(2) and lines added/removed(3)
| # | Name | DevScore | Commits | Lines++ | Lines— |
|---|---|---|---|---|---|
| 1. | Bogdan-Andrei Iancu (@bogdan-iancu) | 68 | 45 | 525 | 1057 |
| 2. | Juha Heinanen (@juha-h) | 65 | 21 | 3516 | 839 |
| 3. | Jan Janak (@janakj) | 57 | 21 | 2910 | 660 |
| 4. | Daniel-Constantin Mierla (@miconda) | 17 | 11 | 126 | 221 |
| 5. | Stefan Darius (@dariusstefan) | 17 | 3 | 1135 | 205 |
| 6. | Henning Westerholt (@henningw) | 15 | 10 | 150 | 162 |
| 7. | Andrei Pelinescu-Onciul | 11 | 7 | 136 | 107 |
| 8. | Miklos Tirpak | 10 | 2 | 799 | 25 |
| 9. | Dan Pascu (@danpascu) | 7 | 5 | 13 | 13 |
| 10. | Ancuta Onofrei | 7 | 1 | 158 | 212 |
All remaining contributors: Saúl Ibarra Corretgé (@saghul), Jiri Kuthan (@jiriatipteldotorg), Elena-Ramona Modroiu, Razvan Crainea (@razvancrainea), UnixDev, Konstantin Bokarius, Norman Brandinger (@NormB), Andreas Granig, Edson Gellert Schubert.
(1) DevScore = author_commits + author_lines_added / (project_lines_added / project_commits) + author_lines_deleted / (project_lines_deleted / project_commits)
(2) including any documentation-related commits, excluding merge commits
(3) ignoring whitespace edits, renamed files and auto-generated files
By Commit Activity
Section titled “By Commit Activity”| # | Name | Commit Activity |
|---|---|---|
| 1. | Stefan Darius (@dariusstefan) | Jun 2026 - Jul 2026 |
| 2. | Razvan Crainea (@razvancrainea) | Jun 2026 - Jun 2026 |
| 3. | Saúl Ibarra Corretgé (@saghul) | Aug 2010 - Aug 2011 |
| 4. | Bogdan-Andrei Iancu (@bogdan-iancu) | Jan 2005 - Jun 2010 |
| 5. | UnixDev | Feb 2009 - Feb 2009 |
| 6. | Henning Westerholt (@henningw) | Aug 2007 - Jul 2008 |
| 7. | Juha Heinanen (@juha-h) | Mar 2004 - May 2008 |
| 8. | Daniel-Constantin Mierla (@miconda) | Nov 2006 - Mar 2008 |
| 9. | Konstantin Bokarius | Mar 2008 - Mar 2008 |
| 10. | Edson Gellert Schubert | Feb 2008 - Feb 2008 |
All remaining contributors: Dan Pascu (@danpascu), Ancuta Onofrei, Elena-Ramona Modroiu, Norman Brandinger (@NormB), Andreas Granig, Andrei Pelinescu-Onciul, Jan Janak (@janakj), Jiri Kuthan (@jiriatipteldotorg), Miklos Tirpak.
(1) including any documentation-related commits, excluding merge commits
Documentation
Section titled “Documentation”Contributors
Section titled “Contributors”Last edited by: Razvan Crainea (@razvancrainea), Saúl Ibarra Corretgé (@saghul), Bogdan-Andrei Iancu (@bogdan-iancu), Henning Westerholt (@henningw), Juha Heinanen (@juha-h), Daniel-Constantin Mierla (@miconda), Konstantin Bokarius, Edson Gellert Schubert, Elena-Ramona Modroiu, Jan Janak (@janakj).
License
Section titled “License”All documentation files (i.e. .md extension) are licensed under the Creative Common License 4.0