kamailio/modules/registrar

registrar Module

Jan Janak

   FhG FOKUS

Daniel-Constantin Mierla

   <miconda@gmail.com>

Juha Heinanen

   <jh@tutpro.com>

Edited by

Jan Janak

Edited by

Bogdan-Andre Iancu

   Copyright © 2003 FhG FOKUS
     __________________________________________________________________

   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)

        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. defaults_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. save usage
   1.29. lookup usage
   1.30. lookup_branches usage
   1.31. registered usage
   1.32. add_sock_hdr usage
   1.33. unregister usage
   1.34. reg_fetch_contacts usage
   1.35. reg_free_contacts usage
   1.36. event_route[usrloc:contact-expired] usage
   1.37. $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)

   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. defaults_expires
        6.4. accepted_regs
        6.5. rejected_regs

   7. Pseudo Variables

        7.1. $ulc(profile=>attr)

1. Overview

   1.1. PATH support
   1.2. GRUU Support

   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
   2.2. External Libraries or Applications

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)
   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)

3.1. 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 maximim percentage from expires
   that will be substracted 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 .. expi
res]
...

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
       rquest 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.
     * 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)
...

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)

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).
       The flags may be given in decimal or hexa 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:
     * -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 1.28. 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 1.29. 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 1.30. 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 - set xavp_rcd with value from matched contact

   This function can be used from ANY_ROUTE.

   Example 1.31. 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.

   This function can be used from REQUEST_ROUTE.

   Example 1.32. 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.

   Example 1.33. 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 1.34. 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 1.35. reg_free_contacts usage
...
reg_free_contacts("callee");
...

5. Event Routes

   5.1. event_route[usrloc:contact-expired]

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 1.36. 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
   6.2. max_contacts
   6.3. defaults_expires
   6.4. accepted_regs
   6.5. rejected_regs

6.1. max_expires

   Value of max_expires parameter.

6.2. max_contacts

   The value of max_contacts parameter.

6.3. defaults_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)

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 - use location domain 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
     * reg-id - reg-id value
     * instance - instance value
     * conid - TCP socket internal connection ID ($null if UDP)

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

   Example 1.37. $ulc(name) usage
...
if(reg_fetch_contacts("location", "$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=>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 happend with the old “nat_flag” module parameter?
   2.2. What happend 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 happend 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 happend 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 http://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:
     * User Mailing List -
       http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users
     * Developer Mailing List -
       http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-dev

   E-mails regarding any stable Kamailio release should be sent to
   <sr-users@lists.sip-router.org> and e-mails regarding development
   versions should be sent to <sr-dev@lists.sip-router.org>.

   If you want to keep the mail private, send it to
   <sr-users@lists.sip-router.org>.

   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.