registrar Module

Jan Janak

FhG FOKUS

Edited by

Jan Janak

Bogdan-Andre Iancu


Table of Contents
1. User's Guide
1.1. Overview
1.2. Dependencies
1.2.1. OpenSER Modules
1.2.2. External Libraries or Applications
1.3. Exported Parameters
1.3.1. default_expires (integer)
1.3.2. min_expires (integer)
1.3.3. max_expires (integer)
1.3.4. default_q (integer)
1.3.5. nat_flag (integer)
1.3.6. sip_natping_flag (integer)
1.3.7. realm_prefix (string)
1.3.8. append_branches (integer)
1.3.9. use_domain (integer)
1.3.10. case_sensitive (integer)
1.3.11. desc_time_order (integer)
1.3.12. received_avp (integer)
1.3.13. received_param (integer)
1.3.14. max_contacts (integer)
1.3.15. retry_after (integer)
1.3.16. sock_flag (integer)
1.3.17. sock_hdr_name (string)
1.3.18. use_branch_flags (integer)
1.4. Exported Functions
1.4.1. save(domain)
1.4.2. save_noreply(domain)
1.4.3. save_memory(domain)
1.4.4. lookup(domain)
1.4.5. registered(domain)
1.4.6. add_sock_hdr(hdr_name)
2. Developer's Guide
3. Frequently Asked Questions
List of Examples
1-1. Set default_expires parameter
1-2. Set min_expires parameter
1-3. Set max_expires parameter
1-4. Set default_q parameter
1-5. Set nat_flag parameter
1-6. Set sip_natping_flag parameter
1-7. Set realm_prefix parameter
1-8. Set append_branches parameter
1-9. Set use_domain parameter
1-10. Set case_sensitive parameter
1-11. Set desc_time_order parameter
1-12. Set received_avp parameter
1-13. Set received_param parameter
1-14. Set max_contacts parameter
1-15. Set retry_after parameter
1-16. Set sock_flag parameter
1-17. Set sock_hdr_namer parameter
1-18. Set use_branch_flagsr parameter
1-19. save usage
1-20. save_noreply usage
1-21. save_memory usage
1-22. lookup usage
1-23. registered usage
1-24. add_sock_hdr usage

Chapter 1. User's Guide

1.1. Overview

The module contains REGISTER processing logic.


1.2. Dependencies

1.2.1. OpenSER Modules

The following modules must be loaded before this module:

  • usrloc - User Location Module.

  • sl - Stateless Replies.


1.2.2. External Libraries or Applications

The following libraries or applications must be installed before running OpenSER with this module loaded:

  • None.


1.3. Exported Parameters

1.3.1. 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).

Default value is 3600.

Example 1-1. Set default_expires parameter

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

1.3.2. 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.

Default value is 60.

Example 1-2. Set min_expires parameter

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

1.3.3. max_expires (integer)

The maximum expires value of a Contact, values higher than this maximum will be automatically set to the maximum. Value 0 disables the checking.

Default value is 0.

Example 1-3. Set max_expires parameter

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

1.3.4. default_q (integer)

The parameter represents default q value for new contacts. Because ser doesn't support float parameter types, the value in the parameter is divided by 100 and stored as float. For example, if you want default_q to be 0.38, use value 38 here.

Default value is 0.

Example 1-4. Set default_q parameter

...
modparam("registrar", "default_q", 100)
...

1.3.5. nat_flag (integer)

The parameter specifies the flag to be used as NAT marker. The idea is to set this flag if a register come behind a NAT; the "save()" functions will save the flag in the usrloc, flag that will be restore by the "lookup()" function.

Default value is -1 (disabled).

Example 1-5. Set nat_flag parameter

...
modparam("registrar", "nat_flag", 6)
...

1.3.6. sip_natping_flag (integer)

The parameter specifies the flat to be used to mark the contacts to be NAT pinged via a SIP request instead if dummy UDP package. The flag will be stored in usrloc by the "save()" functions and internally used by the "nathelper" module. The flag will NOT be restore by the "lookup()" function.

Default value is -1 (disabled).

Example 1-6. Set sip_natping_flag parameter

...
modparam("registrar", "sip_natping_flag", 7)
...

1.3.7. realm_prefix (string)

Prefix to be automatically strip 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 .

Default value is NULL (none).

Example 1-7. Set realm_prefix parameter

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

1.3.8. 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.

Default value is 1.

Example 1-8. Set append_branches parameter

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

1.3.9. use_domain (integer)

If set to 1 then the registrar will use username@domain as address of record. If the variable is set to 0 then only username will be used as the address of record.

Default value is 0.

Example 1-9. Set use_domain parameter

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

1.3.10. case_sensitive (integer)

If set to 1 then AOR comparison will be case sensitive, if set to 0 then AOR comparison will be case insensitive--This is recommended.

Default value is 0.

Example 1-10. Set case_sensitive parameter

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

1.3.11. desc_time_order (integer)

If set to 1 then all contacts will be ordered in descending modification time order. In this case the most recently updated/created contact will be used.

Default value is 0.

Example 1-11. Set desc_time_order parameter

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

1.3.12. received_avp (integer)

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 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 42.

Example 1-12. Set received_avp parameter

...
modparam("registrar", "received_avp", 43)
...

1.3.13. received_param (integer)

The name of the parameter that will be appended to Contacts of 200 OK when the received URI was set by nathelper module.

Default value is "received".

Example 1-13. Set received_param parameter

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

1.3.14. max_contacts (integer)

The parameter can be used to limit the number of contacts per AOR (Address of Record) in the user location database. Value 0 disables the check.

Default value is 0.

Example 1-14. Set max_contacts parameter

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

1.3.15. retry_after (integer)

The registrar can generate 5xx reply to REGISTER 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.

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 1-15. Set retry_after parameter

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

1.3.16. sock_flag (integer)

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

This make sens only in multiple replicated servers scenarios.

Default value is -1 (no flag).

Example 1-16. Set sock_flag parameter

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

1.3.17. sock_hdr_name (string)

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

This make sens only in multiple replicated servers scenarios.

Default value is NULL.

Example 1-17. Set sock_hdr_namer parameter

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

1.3.18. use_branch_flags (integer)

If enabled (has a non zero value), the NAT flag for the additional branches will be pushed in branch flags (in dset/branch array). Otherwise it will be pushed in the message flags. In both cases, the NAT flag for the RURI will be push into message flags.

This make sens to be enabled only if branch route will be used.

Default value is 0 (disabled).

Example 1-18. Set use_branch_flagsr parameter

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

1.4. Exported Functions

1.4.1. save(domain)

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

Meaning of the parameters is as follows:

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

This function can be used from REQUEST_ROUTE.

Example 1-19. save usage

...
save("location");
...

1.4.2. save_noreply(domain)

Same as save() but it doesn't send a reply.

Meaning of the parameters is as follows:

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

This function can be used from REQUEST_ROUTE.

Example 1-20. save_noreply usage

...
save_noreply("location");
...

1.4.3. save_memory(domain)

Same as save() but it updates only the memory cache, even if DB support (any type) is enabled.

Meaning of the parameters is as follows:

  • domain - Logical domain within registrar (Ex: "location").

This function can be used from REQUEST_ROUTE.

Example 1-21. save_memory usage

...
save_memory("location");
...

1.4.4. lookup(domain)

The functions extracts username 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).

Meaning of the parameters is as follows:

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

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

Example 1-22. lookup usage

...
lookup("location");
...

1.4.5. registered(domain)

The function returns true if the AOR in the Request-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 not append branches.

Meaning of the parameters is as follows:

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

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

Example 1-23. registered usage

...
if (registered("location")) {
	sl_send_reply("100", "Trying");
	...
};
...

1.4.6. add_sock_hdr(hdr_name)

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

This make sens 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 1-24. add_sock_hdr usage

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

Chapter 2. Developer's Guide

The module does not provide any API to use in other OpenSER modules.


Chapter 3. Frequently Asked Questions

3.1. Where can I find more about OpenSER?
3.2. Where can I post a question about this module?
3.3. How can I report a bug?

3.1. Where can I find more about OpenSER?

Take a look at http://openser.org/.

3.2. 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 OpenSER release should be sent to and e-mails regarding development versions should be sent to .

If you want to keep the mail private, send it to .

3.3. How can I report a bug?

Please follow the guidelines provided at: http://openser.org/bugs.