registrar Module

Jan Janak

FhG FOKUS

Daniel-Constantin Mierla

Juha Heinanen

Olle E. Johansson

Edvina AB

Edited by

Jan Janak

Edited by

Bogdan-Andre Iancu


Table of Contents

1. Admin Guide
1. Overview
1.1. PATH support
1.2. GRUU Support
2. Dependencies
2.1. Kamailio Modules
2.2. External Libraries or Applications
3. Parameters
3.1. default_expires (integer)
3.2. default_expires_range (integer)
3.3. expires_range (integer)
3.4. min_expires (integer)
3.5. max_expires (integer)
3.6. default_q (integer)
3.7. realm_prefix (string)
3.8. append_branches (integer)
3.9. aor_avp (str)
3.10. case_sensitive (integer)
3.11. received_avp (str)
3.12. received_param (string)
3.13. max_contacts (integer)
3.14. retry_after (integer)
3.15. sock_flag (integer)
3.16. sock_hdr_name (string)
3.17. method_filtering (integer)
3.18. use_path (integer)
3.19. path_mode (integer)
3.20. path_use_received (integer)
3.21. path_check_local (integer)
3.22. reg_callid_avp (string)
3.23. xavp_cfg (string)
3.24. xavp_rcd (string)
3.25. gruu_enabled (integer)
3.26. outbound_mode (integer)
3.27. regid_mode (integer)
3.28. flow_timer (integer)
3.29. contact_max_size (integer)
4. Functions
4.1. save(domain, [, flags [, uri]])
4.2. lookup(domain [, uri])
4.3. lookup_branches(domain)
4.4. registered(domain [, uri [, match_option [, match_action]]])
4.5. add_sock_hdr(hdr_name)
4.6. unregister(domain, uri[, ruid])
4.7. reg_fetch_contacts(domain, uri, profile)
4.8. reg_free_contacts(profile)
5. Event Routes
5.1. event_route[usrloc:contact-expired]
6. Statistics
6.1. max_expires
6.2. max_contacts
6.3. default_expires
6.4. accepted_regs
6.5. rejected_regs
7. Pseudo Variables
7.1. $ulc(profile=>attr)
2. Frequently Asked Questions

List of Examples

1.1. Set default_expires parameter
1.2. Set default_expires_range parameter
1.3. Set expires_range parameter
1.4. Set min_expires parameter
1.5. Set max_expires parameter
1.6. Set default_q parameter
1.7. Set realm_prefix parameter
1.8. Set append_branches parameter
1.9. Set case_sensitive parameter
1.10. Set received_avp parameter
1.11. Set received_param parameter
1.12. Set max_contacts parameter
1.13. Set retry_after parameter
1.14. Set sock_flag parameter
1.15. Set sock_hdr_name parameter
1.16. Set method_filtering parameter
1.17. Set use_path parameter
1.18. Set path_mode parameter
1.19. Set path_use_received parameter
1.20. Set path_check_local parameter
1.21. Set reg_callid_avp parameter
1.22. Set xavp_cfg parameter
1.23. Set xavp_rcd parameter
1.24. Set gruu_enabled parameter
1.25. Set outbound_mode parameter
1.26. Set regid_mode parameter
1.27. Set flow_timer parameter
1.28. Set contact_max_size parameter
1.29. save usage
1.30. lookup usage
1.31. lookup_branches usage
1.32. registered usage
1.33. add_sock_hdr usage
1.34. unregister usage
1.35. reg_fetch_contacts usage
1.36. reg_free_contacts usage
1.37. event_route[usrloc:contact-expired] usage
1.38. $ulc(name) usage

Chapter 1. Admin Guide

Table of Contents

1. Overview
1.1. PATH support
1.2. GRUU Support
2. Dependencies
2.1. Kamailio Modules
2.2. External Libraries or Applications
3. Parameters
3.1. default_expires (integer)
3.2. default_expires_range (integer)
3.3. expires_range (integer)
3.4. min_expires (integer)
3.5. max_expires (integer)
3.6. default_q (integer)
3.7. realm_prefix (string)
3.8. append_branches (integer)
3.9. aor_avp (str)
3.10. case_sensitive (integer)
3.11. received_avp (str)
3.12. received_param (string)
3.13. max_contacts (integer)
3.14. retry_after (integer)
3.15. sock_flag (integer)
3.16. sock_hdr_name (string)
3.17. method_filtering (integer)
3.18. use_path (integer)
3.19. path_mode (integer)
3.20. path_use_received (integer)
3.21. path_check_local (integer)
3.22. reg_callid_avp (string)
3.23. xavp_cfg (string)
3.24. xavp_rcd (string)
3.25. gruu_enabled (integer)
3.26. outbound_mode (integer)
3.27. regid_mode (integer)
3.28. flow_timer (integer)
3.29. contact_max_size (integer)
4. Functions
4.1. save(domain, [, flags [, uri]])
4.2. lookup(domain [, uri])
4.3. lookup_branches(domain)
4.4. registered(domain [, uri [, match_option [, match_action]]])
4.5. add_sock_hdr(hdr_name)
4.6. unregister(domain, uri[, ruid])
4.7. reg_fetch_contacts(domain, uri, profile)
4.8. reg_free_contacts(profile)
5. Event Routes
5.1. event_route[usrloc:contact-expired]
6. Statistics
6.1. max_expires
6.2. max_contacts
6.3. default_expires
6.4. accepted_regs
6.5. rejected_regs
7. Pseudo Variables
7.1. $ulc(profile=>attr)

1. Overview

The module contains REGISTER processing logic. The actual location database is managed by the USRLOC module.

1.1. PATH support

The Register module includes Path support (according to RFC 3327) for usage in registrars and home-proxies.

If path support is enabled in the registrar module, a call to save(...) stores the values of the Path Header(s) along with the contact into usrloc. There are three modes regarding the reply to a REGISTER including one or more Path HFs:

  • off - stores the value of the Path headers into usrloc without passing it back to the UAC in the reply.

  • lazy - stores the Path header and passes it back to the UAC if Path-support is indicated by the path param in the Supported HF.

  • strict - rejects the registration with 420 Bad Extension if there's a Path header but no support for it is indicated by the UAC. Otherwise it's stored and passed back to the UAC.

A call to lookup(...) always uses the path header if found, and inserts it as Route HF either in front of the first Route HF, or after the last Via HF if no Route is present. It also sets the destination uri to the first Path uri, thus overwriting the received-uri, because NAT has to be handled at the outbound-proxy of the UAC (the first hop after client's NAT).

The whole process is transparent to the user, so no config changes are required beside setting the registrar-parameters use_path and path_mode.

1.2. GRUU Support

GRUU (RFC5627) is supported with both public and temporary addresses.

The public GRUU is build based on the '+sip.instance' UUID parameter as recommended by RFC.

The temporary GRUU is built based on internal SRUID (unique id generator) and it is kept the same for the duration of contact validity.

2. Dependencies

2.1. Kamailio Modules

The following modules must be loaded before this module:

  • usrloc - User Location Module.

  • sl - Stateless Replies.

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. default_expires (integer)

If the processed message contains neither Expires HFs nor expires contact parameters, this value will be used for newly created usrloc records. The parameter contains number of second to expire (for example use 3600 for one hour). If it is set to a lower value than the min_expires parameter then it will be ignored. This parameter can be modified via ser config framework. A random value in a specific interval can be selected by using the default_expires_range parameter

Default value is 3600.

Example 1.1. Set default_expires parameter

...
modparam("registrar", "default_expires", 1800)
...

3.2. default_expires_range (integer)

This parameter specifies that the expiry used for newly created usrloc records are not fixed, but a random value in the interval [default_expires-default_expires_range%, default_expires]. The value is between 0 and 100 and represent the maximum percentage from expires that will be subtracted when computing the value. Default is 0, meaning default_expires is left unmodified. This parameter can be modified via the Kamailio config framework.

Default value is 0.

Example 1.2. Set default_expires_range parameter

...
modparam("registrar", "default_expires_range", 30) # +- 30% from default_expires
...

3.3. expires_range (integer)

Similar to default_expires_range, but it applies to the incoming expires value. Default in 0, meaning the expires is left unmodified. This parameter can be modified via the Kamailio config framework.

Default value is 0.

Example 1.3. Set expires_range parameter

...
modparam("registrar", "expires_range", 30) # expires within [0.7*expires .. expires]
...

3.4. min_expires (integer)

The minimum expires value of a Contact. Values lower than this minimum will be automatically set to the minimum. Value 0 disables the checking. This parameter can be modified via the Kamailio config framework.

Default value is 60.

Example 1.4. Set min_expires parameter

...
modparam("registrar", "min_expires", 60)
...

3.5. max_expires (integer)

The maximum accepted expires value of a Contact, values higher than this maximum will be automatically set to the maximum. Value 0 disables the checking. This parameter can be modified via the Kamailio config framework.

Default value is 0.

Example 1.5. Set max_expires parameter

...
modparam("registrar", "max_expires", 120)
...

3.6. default_q (integer)

The parameter represents default q value for new contacts. Because Kamailio doesn't support float parameter types, the value in the parameter is divided by 1000 and stored as float. For example, if you want default_q to be 0.38, use value 380 here. This parameter can be modified via the Kamailio config framework.

Default value is 0.

Example 1.6. Set default_q parameter

...
modparam("registrar", "default_q", 1000)
...

3.7. realm_prefix (string)

Prefix to be automatically stripped from realm. As an alternative to SRV records (not all SIP clients support SRV lookup), a subdomain of the master domain can be defined for SIP purposes (like sip.mydomain.net pointing to same IP address as the SRV record for mydomain.net). By ignoring the realm_prefix "sip.", at registration, sip.mydomain.net will be equivalent to mydomain.net. This parameter can be modified via the Kamailio config framework.

Default value is NULL (none).

Example 1.7. Set realm_prefix parameter

...
modparam("registrar", "realm_prefix", "sip.")
...

3.8. append_branches (integer)

The parameter controls how lookup function processes multiple contacts. If there are multiple contacts for the given username in usrloc and this parameter is set to 1, Request-URI will be overwritten with the highest-q rated contact and the rest will be appended to sip_msg structure and can be later used by tm for forking. If the parameter is set to 0, only Request-URI will be overwritten with the highest-q rated contact and the rest will be left unprocessed. This parameter can be modified via Kamailio config framework.

Default value is 1.

Example 1.8. Set append_branches parameter

...
modparam("registrar", "append_branches", 0)
...

3.9. aor_avp (str)

This module parameter has been removed. Use the 'uri' parameter from functions (e.g., save, lookup, registered).

3.10. case_sensitive (integer)

If set to 1 then AOR comparison and also storing will be case sensitive, if set to 0 then AOR comparison and storing will be case insensitive. This is recommended. This parameter can be modified via Kamailio config framework.

Default value is 0.

Example 1.9. Set case_sensitive parameter

...
modparam("registrar", "case_sensitive", 1)
...

3.11. received_avp (str)

Registrar will store the value of the AVP configured by this parameter in the received column in the user location database. It will leave the column empty if the AVP is empty. The AVP should contain a SIP URI consisting of the source IP, port, and transport protocol of the REGISTER message being processed.

Note

The value of this parameter should be the same as the value of corresponding parameter of nathelper module.

Default value is "NULL" (disabled).

Example 1.10. Set received_avp parameter

...
modparam("registrar", "received_avp", "$avp(s:rcv)")
...

3.12. received_param (string)

The name of the parameter that will be appended to Contact URI's of 200 OK when the received URI was set by the nathelper module. If the value is an empty string, then the parameter is not appended anymore.

Default value is "received".

Example 1.11. Set received_param parameter

...
modparam("registrar", "received_param", "rcv")
...

3.13. max_contacts (integer)

The parameter can be used to limit the number of contacts per AOR (Address of Record) in the user location database. If the maximum number of contacts is exceeded, Kamailio will not accept the registration and send an error response. Value 0 disables the check. This parameter can be modified via the Kamailio config framework. (Please also check the flag for save() if you only want only one active registration).

Default value is 0.

Example 1.12. Set max_contacts parameter

...
# Allow no more than 10 contacts per AOR
modparam("registrar", "max_contacts", 10)
...

3.14. retry_after (integer)

The registrar can generate a 5xx reply to REGISTER requests in various situations. It can, for example, happen when the max_contacts parameter is set and the processing of REGISTER request would exceed the limit. In this case the registrar would generate "503 Service Unavailable" response. This parameter can be modified via the Kamailio config framework.

If you want to add the Retry-After header field in 5xx replies, set this parameter to a value grater than zero (0 means do not add the header field). See section 20.33 of RFC3261 for more details.

Default value is 0 (disabled).

Example 1.13. Set retry_after parameter

...
modparam("registrar", "retry_after", 30)
...

3.15. sock_flag (integer)

Message flag to signal to the registrar module to look into REGISTER request for a header which contains a socket description (IP:port). This socket info will be stored by registrar instead of the received socket info.

This makes sense only in multiple replicated servers scenarios.

Default value is -1 (no flag).

Example 1.14. Set sock_flag parameter

...
modparam("registrar", "sock_flag", 18)
...

3.16. sock_hdr_name (string)

Header which contains a socket description (proto:IP:port) to override the received socket info. The header will be read only if the flag sock_flag is set.

This makes sense only in multiple replicated servers scenarios.

Default value is NULL.

Example 1.15. Set sock_hdr_name parameter

...
modparam("registrar", "sock_hdr_name", "Sock-Info")
...

3.17. method_filtering (integer)

Tells if the contact filtering based on supported methods should be performed during lookup on initial requests without to-tag. It's enabled only if it has a non zero value. Supported methods are listed in the Allow: header in the REGISTER message and stored in the location database.

Default value is 0 (disabled).

Example 1.16. Set method_filtering parameter

...
modparam("registrar", "method_filtering", 1)
...

3.18. use_path (integer)

If set to 1, the Path: header is handled according to the parameter This parameter can be modified via Kamailio config framework. path_mode.

Default value is 0 (disabled).

Example 1.17. Set use_path parameter

...
modparam("registrar", "use_path", 1)
...

3.19. path_mode (integer)

The registrar module implements three different modes regarding the response to a registration which includes one or more Path headers:

  • 0 - The Path header is saved into usrloc, but is not included in the reply.

  • 1 - The Path header is saved into usrloc, but is only included in the reply if path support is indicated in the registration request by the path option in the Supported: header.

  • 2 - The path header is only saved into usrloc, if path support is indicated in the registration request by the path option of the Supported header. If no path support is indicated, the request is rejected with 420 - Bad Extension and the header Unsupported: path is included in the reply along with the received Path header. This mode is the one recommended by RFC-3327.

Default value is 2.

Example 1.18. Set path_mode parameter

...
modparam("registrar", "path_mode", 0)
...

3.20. path_use_received (integer)

If set to 1, the received parameter of the first Path URI of a registration is set as received-uri and the NAT branch flag is set for this contact. This is useful if the registrar is placed behind a SIP loadbalancer, which passes the nat'ed UAC address as received parameter in it's Path uri.

Default value is 0 (disabled).

Example 1.19. Set path_use_received parameter

...
modparam("registrar", "path_use_received", 1)
...

3.21. path_check_local (integer)

If set to 1, when performing a lookup the Path (if present) is evaluated and if the first hop is local (according to myself test), we skip it to avoid unnecessary looping.

This is useful if multiple servers are sharing a common location database, each saving contacts with their local address as the Path.

Default value is 0 (disabled).

Example 1.20. Set path_check_local parameter

...
modparam("registrar", "path_check_local", 1)
...

3.22. reg_callid_avp (string)

obsolete. use match_option in registered function

If reg_callid_avp is defined and populated when the registered() is invoked, the result is TRUE only if an active registration with the specified callID is found.

Default value is NULL (disabled).

Example 1.21. Set reg_callid_avp parameter

...
modparam("registrar", "reg_callid_avp", "$avp(s:avp)")
...

3.23. xavp_cfg (string)

Defines the name of XAVP class to store runtime module config values. The values are stored as inner XAVPs, like $xavp(class=>attribute). Valid inner XAVP names:

  • max_contacts - the number of maximum contacts to be stored for the current registration AoR. It overwrites the 'max_contacts' module parameter value.

  • socket - the string representing the socket on which the register request was received, as alternative to using the sock_hdr.

  • q - q value of contact (integer 0-1000). It overrides q value given in contact header and default_q parameter.

For example. if this parameter is set to 'reg', then the number of maximum contacts can be set in $xavp(reg=>max_contacts).

Default value is NULL (disabled).

Example 1.22. Set xavp_cfg parameter

...
modparam("registrar", "xavp_cfg", "reg")
...

3.24. xavp_rcd (string)

Defines the name of XAVP class to store details from the location records. The values are stored as inner XAVPs, like $xavp(class[0]=>attribute). Valid inner XAVP names:

  • ruid - the record's internal unique id.

  • contact - the record's contact value.

  • expires - the record's expires value.

  • received - the record's received value.

For example. if this parameter is set to 'ulrcd', then values are set in:

  • $xavp(ulrcd[0]=>ruid)

  • $xavp(ulrcd[0]=>contact)

  • $xavp(ulrcd[0]=>received)

Default value is NULL (disabled).

Example 1.23. Set xavp_rcd parameter

...
modparam("registrar", "xavp_rcd", "ulrcd")
...

3.25. gruu_enabled (integer)

If set to 1 and the +sip.instance parameter to Contact header of REGISTER is present, then the value of the parameter is saved to location and pub-gruu and temp-gruu addresses are generated.

Set it to 0 if you want to ignore GRUU extensions in REGISTER.

Default value is 1 (enabled).

Example 1.24. Set gruu_enabled parameter

...
modparam("registrar", "gruu_enabled", 0)
...

3.26. outbound_mode (integer)

If set to 0 this module will accept REGISTER requests that do not contain a Supported: header with the outbound options-tag. The 200 OK response to REGISTER requests that this module generates will not contain Require: or Supported: headers with the outbound options-tag. If the client has a Require: header with the outbound options tag the REGISTER will be rejected with a 420 Bad Extension response.

If set to 1 this module will accept REGISTER requests that do not contain a Supported: header with the outbound options-tag and REGISTER requests that do contain a Supported: or Requires: header with the outbound options-tag. When the client supports outbound the appropriate RFC5626 procedures will be followed.

If set to 2 this module will reject REGISTER requests that do not contain a Supported: header with the outbound options-tag. When the client supports outbound the appropriate RFC5626 procedures will be followed.

Default value is 0.

Example 1.25. Set outbound_mode parameter

...
modparam("registrar", "outbound_mode", 2)
...

3.27. regid_mode (integer)

If set to 0 this module will ignore the regid contact param when saving REGISTER request if the request does not indicate support for outbound.

If set to 1 this module will use regid contact param (if present) when saving REGISTER request even if REGISTER request does not indicate support for outbound.

Default value is 0.

Example 1.26. Set regid_mode parameter

...
modparam("registrar", "regid_mode", 1)
...

3.28. flow_timer (integer)

If set to 0 then this module will not add a Flow-Timer: header to 200 OK responses to REGISTER requests.

If set to > 0 then this module will add a Flow-Timer: header containing this value to 200 OK responses to REGISTER requests. This parameter may only be set to a value > 0 when outbound_mode is set to 1 or 2.

When set to a value greater than 0 this parameter should be set to slightly less than the connection timeout value between the UAC and the network (this corresponds to the core tcp_connection_lifetime option and websocket keepalive_timeout modparam). This parameter is most useful when you have a single edge proxy/registrar or if you have an edge proxy that cannot modify responses. If you are using a separate edge proxy you should consider leaving this parameter set to 0 and adding the Flow-Timer: header on the edge proxy as this allows you to keep all of the timer values for a specific flow in one configuration.

Default value is 0.

Example 1.27. Set flow_timer parameter

...
modparam("registrar", "flow_timer", 25)
...

3.29. contact_max_size (integer)

Max size of URIs in Contact: header.

The size of URIs in Contact: headers are checked to be lower or equal to this value. A warning is logged and a 400 Bad Request is sent in response to REGISTER requests with contact URIs that are longer than this value.

If a database is used then you must make sure that your database model supports strings of the configured size in the column contact of the table specified in save() function.

Default value is 512.

Example 1.28. Set contact_max_size parameter

...
modparam("registrar", "contact_max_size", 1024)
...

4. Functions

4.1.  save(domain, [, flags [, uri]])

The function processes a REGISTER message. It can add, remove or modify location records (in usrloc) depending on Contact and Expires HFs in the REGISTER message. On success and when called from the REQUEST_ROUTE, 200 OK will be returned listing all contacts that are currently in the location database. On an error, an error message will be sent with a short description in reason phrase.

Meaning of the parameters is as follows:

  • domain - Logical domain within the registrar. If a database is used then this must be name of the table which stores the contacts.

  • flags (optional) - the value may be a bitwise OR of the following flags:

    • 0x01 - save the contacts only in memory cache without no DB operation;

    • 0x02 - do not generate a SIP reply to the current REGISTER request. When used in ONREPLY_ROUTE, this parameter is obsolete.

    • 0x04 - store and maintain one contact per AoR. If there are other contact addresses for AoR not matching current registration, remove them. This mode ensures one contact per AoR (user).

    • 0x08 - Do not apply expires_range or default_expires_range to this registration.

    The flags may be given in decimal or hexadecimal format.

  • uri (optional - flags param has to be set and can be 0 for default behavior) - SIP URI to do be used instead of To header URI. It can be a dynamic string with pseudo-variables.

Return codes:

  • -2 - error, too many contacts for AOR.

    -1 - error.

    1 - contacts inserted.

    2 - contacts updated.

    3 - contacts deleted.

    4 - contacts returned.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE and REPLY_ROUTE.

Example 1.29. save usage

...
save("location");
save("location", "0x01");
save("location", "0x00", "sip:test@kamailio.org");
...

4.2.  lookup(domain [, uri])

The lookup function extracts username and/or domain from Request-URI and tries to find all contacts for the username in usrloc. If there are no such contacts, -1 will be returned. If there are such contacts, Request-URI will be overwritten with the contact that has the highest q value and optionally the rest will be appended to the message (depending on append_branches parameter value).

If the method_filtering option is enabled and request is initial request without to-tag, the lookup function will return only the contacts that support the method of the processed request.

Meaning of the parameters is as follows:

  • domain - Name of table that should be used for the lookup.

  • uri (optional) - SIP URI to do be used instead of R-URI. It can be a dynamic string with pseudo-variables.

Return codes:

  • 1 - contacts found and returned.

    -1 - no contact found.

    -2 - contacts found, but method not supported.

    -3 - internal error during processing.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

Example 1.30. lookup usage

...
lookup("location");
switch ($retcode) {
    case -1:
    case -3:
        sl_send_reply("404", "Not Found");
        exit;
    case -2:
        sl_send_reply("405", "Not Found");
        exit;
};
...

4.3.  lookup_branches(domain)

The function performs lookup(domain) on r-uri and additional branches (only branches that have no other attributes set than uri).

Meaning of the parameters is as follows:

  • domain - Name of table that should be used for the lookup.

Return codes are propagated from the lookup(domain) function.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

Example 1.31. lookup_branches usage

...
lookup_branches("location");
...

4.4.  registered(domain [, uri [, match_option [, match_action]]])

The function returns true if the AOR in the URI is registered, false otherwise. The function does not modify the message being process, it neither rewrites the Request-URI if a contact is found nor append branches. If uri parameter is not provided, then it considered to be the Request-URI for SIP requests and To-URI for SIP replies.

Meaning of the parameters is as follows:

  • domain - Name of table that should be used for the lookup.

  • uri (optional) - SIP URI to do be used instead of Request/To-URI. It can be a dynamic string with pseudo-variables.

  • match_option (optional) - flag parameter to restrict contact search. use reg_xavp_cfg to set the values to compare to.

    flag values is as follows:

    • 1 - match_callid

    • 2 - match_received

    • 4 - match_contact

  • match_action (optional) - actions to perform when match is positive.

    flag values is as follows:

    • 1 - restore the xavps associated with the matched contact

    • 2 - skip adding the matched location record attributes to xavp_rcd (e.g., the ruid, contact, received, ...)

This function can be used from ANY_ROUTE.

Example 1.32. registered usage

...
if (registered("location")) {
	sl_send_reply("100", "Trying");
	...
};
...
$xavp(regcfg=>match_received) = $su;
if (registered("location","$rz:$Au", 2)) {
	sl_send_reply("100", "Trying");
	...
};
...

4.5.  add_sock_hdr(hdr_name)

Adds a new header to the current REGISTER request with hdr_name which contains the description of the received socket (proto:ip:port)

This makes sense only in multiple replicated servers scenarios.

Meaning of the parameters is as follows:

  • hdr_name - header name to be used, it can be a static string or contain variables.

This function can be used from REQUEST_ROUTE.

Example 1.33. add_sock_hdr usage

...
add_sock_hdr("Sock-Info");
...

4.6.  unregister(domain, uri[, ruid])

The function removes contacts associated with 'uri' from the location database. If 'ruid' is provided a specific contact is removed, if 'ruid' is not provided all the current contacts are removed. If 'ruid' is provided and the usrloc module is using db_mode=3, 'uri' does not need to be given and can be empty string.

Meaning of the parameters is as follows:

  • domain - Name of table that should be used for the lookup or contact addresses.

  • uri - The SIP URI address of the user which to remove the contact addresses for. It can contain pseudo-variables that are evaluated at runtime.

  • ruid - The record unique ID for a a specific contact to be removed. It can contain pseudo-variables that are evaluated at runtime.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

Return values:

  • 0 - Successfully deleted contact(s)

  • -1 - Failed to extract or parse address of record from argument

  • -2 - Error in unregistering user

  • -3 - Contacts for AOR not found

Example 1.34. unregister usage

...
unregister("location", "$ru");
unregister("location", "sip:user@kamailio.org");
unregister("location", "$ru", "$ulc(caller=>ruid)");
unregister("location", "", "$ruid");
...

4.7.  reg_fetch_contacts(domain, uri, profile)

The function fetches the contacts for 'uri' from table 'domain' to pseudo-variable $ulc(profile).

Meaning of the parameters is as follows:

  • domain - Name of table that should be used for the lookup of contact addresses.

  • uri - The SIP URI address of the user which to fetch the contact addresses for. It can contain pseudo-variables that are evaluated at runtime.

  • profile - Name of $ulc pseudo-variable profile that will store the fetched contacts. It is a static string.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

Example 1.35. reg_fetch_contacts usage

...
reg_fetch_contacts("location", "$ru", "callee");
reg_fetch_contacts("location", "sip:user@kamailio.org", "caller");
...

4.8.  reg_free_contacts(profile)

The function frees the contacts from pseudo-variable $ulc(profile). Should be called to release the content of a profile. Anyhow, fetching a new contact addresses set over a profile will release any existing data in that profile.

Meaning of the parameters is as follows:

  • profile - Name of $ulc pseudo-variable profile that stores fetched contacts. It is a static string.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

Example 1.36. reg_free_contacts usage

...
reg_free_contacts("callee");
...

5. Event Routes

5.1. event_route[usrloc:contact-expired]

Executed when a contact in location table has expired. The variable $ulc(exp=>...) is filled with the attributes of the expired contact.

Example 1.37. event_route[usrloc:contact-expired] usage

...
event_route[usrloc:contact-expired] {
    xlog("expired contact for $ulc(exp=>aor)\n");
}
...

6. Statistics

6.1. max_expires

Value of max_expires parameter.

6.2. max_contacts

The value of max_contacts parameter.

6.3. default_expires

The value of default_expires parameter.

6.4. accepted_regs

Number of accepted registrations.

6.5. rejected_regs

Number of rejected registrations.

7. Pseudo Variables

7.1. $ulc(profile=>attr)

Access the attributes of contact addresses stored in 'profile'. It must be used after a call of reg_fetch_contacts().

The profile has to be one of the values used with reg_fetch_contacts().

The attr can be:

  • aor - address of record

  • domain - used location domain/table name

  • aorhash - hash id for the record

  • addr - contact address

  • path - path vector

  • received - received address

  • expires - expires value

  • callid - call-id header value

  • q - the q value

  • cseq - the cseq value

  • flags - flags value

  • cflags - cflags value

  • user_agent - user agent

  • socket - local socket

  • modified - last modified time

  • methods - methods value

  • count - number of contacts

  • ruid - record unique ID

  • regid - reg-id value

  • instance - instance value

  • conid - TCP socket internal connection ID ($null if UDP)

  • server_id - server_id value

The pseudo-variable accepts positive index value to access a specific contact record.

Example 1.38. $ulc(name) usage

...
if(reg_fetch_contacts("location", "$fu", "caller"))
{
  xlog("caller=>aor: $(ulc(caller=>aor))\n");
  xlog("caller=>domain: $(ulc(caller=>domain))\n");
  xlog("caller=>aorhash $(ulc(caller=>aorhash))\n");
  xlog("caller=>count $(ulc(caller=>count))\n");
  $var(i) = 0;
  while($var(i) < $(ulc(caller=>count)))
  {
    xlog("--- contact [$var(i)]\n");
    xlog("caller=>addr:       $(ulc(caller=>addr)[$var(i)])\n");
    xlog("caller=>path:       $(ulc(caller=>path)[$var(i)])\n");
    xlog("caller=>received:   $(ulc(caller=>received)[$var(i)])\n");
    xlog("caller=>expires:    $(ulc(caller=>expires)[$var(i)])\n");
    xlog("caller=>callid:     $(ulc(caller=>callid)[$var(i)])\n");
    xlog("caller=>regid:      $(ulc(caller=>regid)[$var(i)])\n");
    xlog("caller=>q:          $(ulc(caller=>q)[$var(i)])\n");
    xlog("caller=>cseq:       $(ulc(caller=>cseq)[$var(i)])\n");
    xlog("caller=>flags:      $(ulc(caller=>flags)[$var(i)])\n");
    xlog("caller=>cflags:     $(ulc(caller=>cflags)[$var(i)])\n");
    xlog("caller=>user_agent: $(ulc(caller=>user_agent)[$var(i)])\n");
    xlog("caller=>socket:     $(ulc(caller=>socket)[$var(i)])\n");
    xlog("caller=>modified:   $(ulc(caller=>modified)[$var(i)])\n");
    xlog("caller=>methods:    $(ulc(caller=>methods)[$var(i)])\n");
    $var(i) = $var(i) + 1;
  }
}
...

Chapter 2. Frequently Asked Questions

2.1. What happened with the old “nat_flag” module parameter?
2.2. What happened with the old “use_domain” module parameter?
2.3. What happened with the old “save_noreply” and “save_memory” functions?
2.4. Where can I find more about Kamailio?
2.5. Where can I post a question about this module?
2.6. How can I report a bug?
2.7. What happened to the desc_time_order parameter?

2.1.

What happened with the old nat_flag module parameter?

In was removed, as the module internally loads this value from the USRLOC module (see the nat_bflag USRLOC parameter).

2.2.

What happened with the old use_domain module parameter?

In was removed, as the module internally loads this option from the USRLOC module. This was done in order to simplify the configuration.

2.3.

What happened with the old save_noreply and save_memory functions?

There functions were merged into the new save(domain,flags) functions. If a reply should be sent or if the DB should be updated also is controlled via the flags.

2.4.

Where can I find more about Kamailio?

Take a look at https://www.kamailio.org/.

2.5.

Where can I post a question about this module?

First at all check if your question was already answered on one of our mailing lists:

E-mails regarding any stable Kamailio release should be sent to and e-mails regarding development versions should be sent to .

2.6.

How can I report a bug?

Please follow the guidelines provided at: https://github.com/kamailio/kamailio/issues.

2.7.

What happened to the desc_time_order parameter?

It was removed, as its functionality was migrated into usrloc module, were there is a parameter with the same name.