dialog Module

Bogdan-Andrei Iancu

Edited by

Bogdan-Andrei Iancu

Edited by

Vladut-Stefan Paiu

Revision History
Revision $Revision: 8771 $$Date$

Table of Contents

1. Admin Guide
1.1. Overview
1.2. How it works
1.3. Dialog profiling
1.4. Dialog replication
1.5. Dependencies
1.5.1. OpenSIPS Modules
1.5.2. External Libraries or Applications
1.6. Exported Parameters
1.6.1. enable_stats (integer)
1.6.2. hash_size (integer)
1.6.3. log_profile_hash_size (integer)
1.6.4. rr_param (string)
1.6.5. default_timeout (integer)
1.6.6. dlg_extra_hdrs (string)
1.6.7. dlg_match_mode (integer)
1.6.8. db_url (string)
1.6.9. db_mode (integer)
1.6.10. db_update_period (integer)
1.6.11. ping_interval (integer)
1.6.12. table_name (string)
1.6.13. call_id_column (string)
1.6.14. from_uri_column (string)
1.6.15. from_tag_column (string)
1.6.16. to_uri_column (string)
1.6.17. to_tag_column (string)
1.6.18. from_cseq_column (string)
1.6.19. to_cseq_column (string)
1.6.20. from_route_column (string)
1.6.21. to_route_column (string)
1.6.22. from_contact_column (string)
1.6.23. to_contact_column (string)
1.6.24. from_sock_column (string)
1.6.25. to_sock_column (string)
1.6.26. dlg_id_column (string)
1.6.27. state_column (string)
1.6.28. start_time_column (string)
1.6.29. timeout_column (string)
1.6.30. profiles_column (string)
1.6.31. vars_column (string)
1.6.32. sflags_column (string)
1.6.33. mflags_column (string)
1.6.34. flags_column (string)
1.6.35. profiles_with_value (string)
1.6.36. profiles_no_value (string)
1.6.37. db_flush_vals_profiles (int)
1.6.38. timer_bulk_del_no (int)
1.6.39. cachedb_url (string)
1.6.40. profile_value_prefix (string)
1.6.41. profile_no_value_prefix (string)
1.6.42. profile_size_prefix (string)
1.6.43. profile_timeout (int)
1.6.44. accept_replicated_dialogs (int)
1.6.45. replicate_dialogs_to (string)
1.6.46. th_callid_passwd (string)
1.6.47. th_callid_prefix (string)
1.6.48. th_passed_contact_uri_params (string)
1.6.49. th_passed_contact_params (string)
1.7. Exported Functions
1.7.1. create_dialog()
1.7.2. match_dialog()
1.7.3. validate_dialog()
1.7.4. fix_route_dialog()
1.7.5. get_dialog_info(attr,var,key,key_val)
1.7.6. set_dlg_profile(profile,[value])
1.7.7. unset_dlg_profile(profile,[value])
1.7.8. is_in_profile(profile,[value])
1.7.9. get_profile_size(profile,[value],size)
1.7.10. set_dlg_flag(idx)
1.7.11. test_and_set_dlg_flag(idx, value)
1.7.12. reset_dlg_flag(idx)
1.7.13. is_dlg_flag_set(idx)
1.7.14. store_dlg_value(name,val)
1.7.15. fetch_dlg_value(name,pvar)
1.7.16. topology_hiding()
1.8. Exported statistics
1.8.1. active_dialogs
1.8.2. early_dialogs
1.8.3. processed_dialogs
1.8.4. expired_dialogs
1.8.5. failed_dialogs
1.8.6. create_sent
1.8.7. update_sent
1.8.8. delete_sent
1.8.9. create_recv
1.8.10. update_recv
1.8.11. delete_recv
1.9. Exported MI Functions
1.9.1. dlg_list
1.9.2. dlg_list_ctx
1.9.3. dlg_end_dlg
1.9.4. profile_get_size
1.9.5. profile_list_dlgs
1.9.6. profile_get_values
1.9.7. dlg_db_sync
1.9.8. dlg_restore_db
1.9.9. list_all_profiles
1.10. Exported pseudo-variables
1.10.1. $DLG_count
1.10.2. $DLG_status
1.10.3. $DLG_lifetime
1.10.4. $DLG_flags
1.10.5. $DLG_dir
1.10.6. $DLG_did
1.10.7. $DLG_end_reason
1.10.8. $DLG_timeout
1.10.9. $DLG_callee_callid
1.10.10. $dlg_val(name)
1.11. Exported Events
1.11.1. E_DLG_STATE_CHANGED
2. Developer Guide
2.1. Available Functions
2.1.1. register_dlgcb (dialog, type, cb, param, free_param_cb)
3. Frequently Asked Questions

List of Examples

1.1. Set enable_stats parameter
1.2. Set hash_size parameter
1.3. Set hash_size parameter
1.4. Set rr_param parameter
1.5. Set default_timeout parameter
1.6. Set dlf_extra_hdrs parameter
1.7. Set dlg_match_mode parameter
1.8. Set db_url parameter
1.9. Set db_mode parameter
1.10. Set db_update_period parameter
1.11. Set ping_interval parameter
1.12. Set table_name parameter
1.13. Set call_id_column parameter
1.14. Set from_uri_column parameter
1.15. Set from_tag_column parameter
1.16. Set to_uri_column parameter
1.17. Set to_tag_column parameter
1.18. Set from_cseq_column parameter
1.19. Set to_cseq_column parameter
1.20. Set from_route_column parameter
1.21. Set to_route_column parameter
1.22. Set from_contact_column parameter
1.23. Set to_contact_column parameter
1.24. Set from_sock_column parameter
1.25. Set to_sock_column parameter
1.26. Set dlg_id_column parameter
1.27. Set state_column parameter
1.28. Set start_time_column parameter
1.29. Set timeout_column parameter
1.30. Set profiles_column parameter
1.31. Set vars_column parameter
1.32. Set sflags_column parameter
1.33. Set mflags_column parameter
1.34. Set flags_column parameter
1.35. Set profiles_with_value parameter
1.36. Set profiles_no_value parameter
1.37. Set db_flush_vals_profiles parameter
1.38. Set timer_bulk_del_no parameter
1.39. Set cachedb_url parameter
1.40. Set profile_value_prefix parameter
1.41. Set profile_no_value_prefix parameter
1.42. Set profile_size_prefix parameter
1.43. Set profile_timeout parameter
1.44. Set accept_replicated_dialogs parameter
1.45. Set replicate_dialogs_to parameter
1.46. Set th_callid_passwd parameter
1.47. Set th_callid_prefix parameter
1.48. Set th_passed_contact_uri_params parameter
1.49. Set th_passed_contact_params parameter
1.50. create_dialog() usage
1.51. match_dialog() usage
1.52. validate_dialog() usage
1.53. fix_route_dialog() usage
1.54. get_dialog_info usage
1.55. set_dlg_profile usage
1.56. unset_dlg_profile usage
1.57. is_in_profile usage
1.58. get_profile_size usage
1.59. set_dlg_flag usage
1.60. test_and_set_dlg_flag usage
1.61. reset_dlg_flag usage
1.62. is_dlg_flag_set usage
1.63. store_dlg_value usage
1.64. fetch_dlg_value usage
1.65. topology_hiding usage
1.66. calling match_dialog() function for topology hiding sequential requests

Chapter 1. Admin Guide

1.1. Overview

The dialog module provides dialog awareness to the OpenSIPS proxy. Its functionality is to keep trace of the current dialogs, to offer information about them (like how many dialogs are active).

Aside tracking, the dialog module offers functionalities like flags and attributes per dialog (persistent data across dialog), dialog profiling and dialog termination (on timeout base or external triggered).

The module, via an internal API, also provide the foundation to build on top of it more complex dialog-based functionalities via other OpenSIPS modules.

1.2. How it works

To create the dialog associated to an initial request, you must call the create_dialog() function, with or without parameter..

The dialog is automatically destroyed when a “BYE” is received. In case of no “BYE”, the dialog lifetime is controlled via the default timeout (see “default_timeout” - Section 1.6.5, “default_timeout (integer)”) and custom timeout (see “$DLG_timeout” - Section 1.10.8, “$DLG_timeout).

1.3. Dialog profiling

Dialog profiling is a mechanism that helps in classifying, sorting and keeping trace of certain types of dialogs, using whatever properties of the dialog (like caller, destination, type of calls, etc). Dialogs can be dynamically added in different (and several) profile tables - logically, each profile table can have a special meaning (like dialogs outside the domain, dialogs terminated to PSTN, etc).

There are two types of profiles:

  • with no value - a dialog simply belongs to a profile. (like outbound calls profile). There is no other additional information to describe the dialog's belonging to the profile;

  • with value - a dialog belongs to a profile having a certain value (like in caller profile, where the value is the caller ID). The belonging of the dialog to the profile is strictly related to the value.

A dialog can be added to multiple profiles in the same time.

Profiles are visible (at the moment) in the request route (for initial and sequential requests) and in the branch, failure and reply routes of the original request.

Dialog profiles can also be used in distributed systems, using the OpenSIPS CacheDB Interface. This feature allows you to share dialog profile information with multiple OpenSIPS instaces that use the same CacheDB backend. In order to do that, the cachedb_url parameter must be defined. Also, the profile must be marked as shared, by adding the '/s' suffix to the name of the profile in the profiles_with_value or profiles_no_value parameters.

1.4. Dialog replication

Dialog replication is a mechanism used to mirror all dialog changes taking place in one OpenSIPS instance to one or more other different instances. The logic is simplified by using the core Binary Internal Interface to build and send the replication-related UDP packets.

The feature is especially useful when dealing with very large systems, where failover through a database backend is no longer feasible, due to the high amount of time required for the backup instance to load the dialog information stored in a typical dialog table by the crashed instance.

Configuring both receival and sending of dialog replication packets is trivial and can be done by using the accept_replicated_dialogs and replicate_dialogs_to parameters of the module. In addition to this, the module also exports several statistics regarding the number of replication packets sent/received.

1.5. Dependencies

1.5.1. OpenSIPS Modules

The following modules must be loaded before this module:

  • TM - Transaction module

  • RR - Record-Route module

1.5.2. External Libraries or Applications

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

  • None.

1.6. Exported Parameters

1.6.1. enable_stats (integer)

If the statistics support should be enabled or not. Via statistic variables, the module provide information about the dialog processing. Set it to zero to disable or to non-zero to enable it.

Default value is “1 (enabled)”.

Example 1.1. Set enable_stats parameter

...
modparam("dialog", "enable_stats", 0)
...

1.6.2. hash_size (integer)

The size of the hash table internally used to keep the dialogs. A larger table is much faster but consumes more memory. The hash size must be a power of 2 number.

IMPORTANT: If dialogs' information should be stored in a database, a constant hash_size should be used, otherwise the restored process will not take place. If you really want to modify the hash_size you must delete all table's rows before restarting OpenSIPS.

Default value is “4096”.

Example 1.2. Set hash_size parameter

...
modparam("dialog", "hash_size", 1024)
...

1.6.3. log_profile_hash_size (integer)

The size of the hash table internally used to store profile->dialog associations. A larger table can provide more parallel operations but consumes more memory. The hash size is provided as the base 2 logarithm(e.g. log_profile_hash_size =4 means the table has 2^4 entries).

Default value is “4”.

Example 1.3. Set hash_size parameter

...
modparam("dialog", "log_profile_hash_size", 5) #set a table size of 32
...

1.6.4. rr_param (string)

Name of the Record-Route parameter to be added with the dialog cookie. It is used for fast dialog matching of the sequential requests.

Default value is “did”.

Example 1.4. Set rr_param parameter

...
modparam("dialog", "rr_param", "xyz")
...

1.6.5. default_timeout (integer)

The default dialog timeout (in seconds) if no custom one is set.

Default value is “43200 (12 hours)”.

Example 1.5. Set default_timeout parameter

...
modparam("dialog", "default_timeout", 21600)
...

1.6.6. dlg_extra_hdrs (string)

A string containing the extra headers (full format, with EOH) to be added in the requests generated by the module (like BYEs).

Default value is “NULL”.

Example 1.6. Set dlf_extra_hdrs parameter

...
modparam("dialog", "dlg_extra_hdrs", "Hint: credit expired\r\n")
...

1.6.7. dlg_match_mode (integer)

How the seqential requests should be matched against the known dialogs. The modes are a combination between matching based on a cookie (DID) stored as cookie in Record-Route header and the matching based on SIP elements (as in RFC3261).

The supported modes are:

  • 0 - DID_ONLY - the match is done exclusively based on DID;

  • 1 - DID_FALLBACK - the match is first tried based on DID and if not present, it will fallback to SIP matching;

  • 2 - DID_NONE - the match is done exclusively based on SIP elements; no DID information is added in RR.

Default value is “0 (DID_ONLY)”.

Example 1.7. Set dlg_match_mode parameter

...
modparam("dialog", "dlg_match_mode", 1)
...

1.6.8. db_url (string)

If you want to store the information about the dialogs in a database a database url must be specified.

Default value is “mysql://opensips:opensipsrw@localhost/opensips”.

Example 1.8. Set db_url parameter

...
modparam("dialog", "db_url", "dbdriver://username:password@dbhost/dbname")
...

1.6.9. db_mode (integer)

Describe how to push into the DB the dialogs' information from memory.

The supported modes are:

  • 0 - NO_DB - the memory content is not flushed into DB;

  • 1 - REALTIME - any dialog information changes will be reflected into the database immediately.

  • 2 - DELAYED - the dialog information changes will be flushed into the DB periodically, based on a timer routine.

  • 3 - SHUTDOWN - the dialog information will be flushed into DB only at shutdown - no runtime updates.

Default value is “0”.

Example 1.9. Set db_mode parameter

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

1.6.10. db_update_period (integer)

The interval (seconds) at which to update dialogs' information if you chose to store the dialogs' info at a given interval. A too short interval will generate intensive database operations, a too large one will not notice short dialogs.

Default value is “60”.

Example 1.10. Set db_update_period parameter

...
modparam("dialog", "db_update_period", 120)
...

1.6.11. ping_interval (integer)

The interval (seconds) at which OpenSIPS will generate in-dialog pings for dialogs.

Default value is “30”.

Example 1.11. Set ping_interval parameter

...
modparam("dialog", "ping_interval", 20)
...

1.6.12. table_name (string)

If you want to store the information about the dialogs in a database a table name must be specified.

Default value is “dialog”.

Example 1.12. Set table_name parameter

...
modparam("dialog", "table_name", "my_dialog")
...

1.6.13. call_id_column (string)

The column's name in the database to store the dialogs' callid.

Default value is “callid”.

Example 1.13. Set call_id_column parameter

...
modparam("dialog", "call_id_column", "callid_c_name")
...

1.6.14. from_uri_column (string)

The column's name in the database to store the caller's sip address.

Default value is “from_uri”.

Example 1.14. Set from_uri_column parameter

...
modparam("dialog", "from_uri_column", "from_uri_c_name")
...

1.6.15. from_tag_column (string)

The column's name in the database to store the From tag from the Invite request.

Default value is “from_tag”.

Example 1.15. Set from_tag_column parameter

...
modparam("dialog", "from_tag_column", "from_tag_c_name")
...

1.6.16. to_uri_column (string)

The column's name in the database to store the calee's sip address.

Default value is “to_uri”.

Example 1.16. Set to_uri_column parameter

...
modparam("dialog", "to_uri_column", "to_uri_c_name")
...

1.6.17. to_tag_column (string)

The column's name in the database to store the To tag from the 200 OK response to the Invite request, if present.

Default value is “to_tag”.

Example 1.17. Set to_tag_column parameter

...
modparam("dialog", "to_tag_column", "to_tag_c_name")
...

1.6.18. from_cseq_column (string)

The column's name in the database to store the cseq from caller side.

Default value is “caller_cseq”.

Example 1.18. Set from_cseq_column parameter

...
modparam("dialog", "from_cseq_column", "from_cseq_c_name")
...

1.6.19. to_cseq_column (string)

The column's name in the database to store the cseq from callee side.

Default value is “callee_cseq”.

Example 1.19. Set to_cseq_column parameter

...
modparam("dialog", "to_cseq_column", "to_cseq_c_name")
...

1.6.20. from_route_column (string)

The column's name in the database to store the route records from caller side (proxy to caller).

Default value is “caller_route_set”.

Example 1.20. Set from_route_column parameter

...
modparam("dialog", "from_route_column", "from_route_c_name")
...

1.6.21. to_route_column (string)

The column's name in the database to store the route records from callee side (proxy to callee).

Default value is “callee_route_set”.

Example 1.21. Set to_route_column parameter

...
modparam("dialog", "to_route_column", "to_route_c_name")
...

1.6.22. from_contact_column (string)

The column's name in the database to store the caller's contact uri.

Default value is “caller_contact”.

Example 1.22. Set from_contact_column parameter

...
modparam("dialog", "from_contact_column", "from_contact_c_name")
...

1.6.23. to_contact_column (string)

The column's name in the database to store the callee's contact uri.

Default value is “callee_contact”.

Example 1.23. Set to_contact_column parameter

...
modparam("dialog", "to_contact_column", "to_contact_c_name")
...

1.6.24. from_sock_column (string)

The column's name in the database to store the information about the local interface receiving the traffic from caller.

Default value is “caller_sock”.

Example 1.24. Set from_sock_column parameter

...
modparam("dialog", "from_sock_column", "from_sock_c_name")
...

1.6.25. to_sock_column (string)

The column's name in the database to store information about the local interface receiving the traffic from callee.

Default value is “callee_sock”.

Example 1.25. Set to_sock_column parameter

...
modparam("dialog", "to_sock_column", "to_sock_c_name")
...

1.6.26. dlg_id_column (string)

The column's name in the database to store the dialogs' id information.

Default value is “hash_id”.

Example 1.26. Set dlg_id_column parameter

...
modparam("dialog", "dlg_id_column", "dlg_id_c_name")
...

1.6.27. state_column (string)

The column's name in the database to store the dialogs' state information.

Default value is “state”.

Example 1.27. Set state_column parameter

...
modparam("dialog", "state_column", "state_c_name")
...

1.6.28. start_time_column (string)

The column's name in the database to store the dialogs' start time information.

Default value is “start_time”.

Example 1.28. Set start_time_column parameter

...
modparam("dialog", "start_time_column", "start_time_c_name")
...

1.6.29. timeout_column (string)

The column's name in the database to store the dialogs' timeout.

Default value is “timeout”.

Example 1.29. Set timeout_column parameter

...
modparam("dialog", "timeout_column", "timeout_c_name")
...

1.6.30. profiles_column (string)

The column's name in the database to store the dialogs' profiles.

Default value is “profiles”.

Example 1.30. Set profiles_column parameter

...
modparam("dialog", "profiles_column", "profiles_c_name")
...

1.6.31. vars_column (string)

The column's name in the database to store the dialogs' vars.

Default value is “vars”.

Example 1.31. Set vars_column parameter

...
modparam("dialog", "vars_column", "vars_c_name")
...

1.6.32. sflags_column (string)

The column's name in the database to store the dialogs' script flags.

Default value is “script_flags”.

Example 1.32. Set sflags_column parameter

...
modparam("dialog", "sflags_column", "sflags_c_name")
...

1.6.33. mflags_column (string)

The column's name in the database to store the dialogs' module flags.

Default value is “module_flags”.

Example 1.33. Set mflags_column parameter

...
modparam("dialog", "mflags_column", "mflags_c_name")
...

1.6.34. flags_column (string)

The column's name in the database to store the dialogs' flags.

Default value is “flags”.

Example 1.34. Set flags_column parameter

...
modparam("dialog", "flags_column", "flags_c_name")
...

1.6.35. profiles_with_value (string)

List of names for profiles with values.

Default value is “empty”.

Example 1.35. Set profiles_with_value parameter

...
modparam("dialog", "profiles_with_value", "caller ; my_profile; share/s")
...

1.6.36. profiles_no_value (string)

List of names for profiles without values.

Default value is “empty”.

Example 1.36. Set profiles_no_value parameter

...
modparam("dialog", "profiles_no_value", "inbound ; outbound ; shared/s")
...

1.6.37. db_flush_vals_profiles (int)

Pushes dialog values, profiles and flags into the database along with other dialog state information (see db_mode 1 and 2).

Default value is “empty”.

Example 1.37. Set db_flush_vals_profiles parameter

...
modparam("dialog", "db_flush_vals_profiles", 1)
...

1.6.38. timer_bulk_del_no (int)

The number of dialogs that should be attempted to be deleted at the same time ( a single query ) from the DB back-end.

Default value is “1”.

Example 1.38. Set timer_bulk_del_no parameter

...
modparam("dialog", "timer_bulk_del_no", 10)
...

1.6.39. cachedb_url (string)

Enables distributed dialog profiles and specifies the backend that should be used by the CacheDB interface.

Default value is “empty”.

Example 1.39. Set cachedb_url parameter

...
modparam("dialog", "cachedb_url", "redis://127.0.0.1:6379")
...

1.6.40. profile_value_prefix (string)

Specifies what prefix should be added to the profiles with value when they are inserted into CacheDB backed. This is only used when distributed profiles are enabled.

Default value is “dlg_val_”.

Example 1.40. Set profile_value_prefix parameter

...
modparam("dialog", "profile_value_prefix", "dlgv_")
...

1.6.41. profile_no_value_prefix (string)

Specifies what prefix should be added to the profiles without value when they are inserted into CacheDB backed. This is only used when distributed profiles are enabled.

Default value is “dlg_noval_”.

Example 1.41. Set profile_no_value_prefix parameter

...
modparam("dialog", "profile_no_value_prefix", "dlgnv_")
...

1.6.42. profile_size_prefix (string)

Specifies what prefix should be added to the entity that holds the profiles with value size in CacheDB backed. This is only used when distributed profiles are enabled.

Default value is “dlg_size_”.

Example 1.42. Set profile_size_prefix parameter

...
modparam("dialog", "profile_size_prefix", "dlgs_")
...

1.6.43. profile_timeout (int)

Specifies how long a dialog profile should be kept in the CacheDB until it expires. This is only used when distributed profiles are enabled.

Default value is “86400”.

Example 1.43. Set profile_timeout parameter

...
modparam("dialog", "profile_timeout", "43200")
...

1.6.44. accept_replicated_dialogs (int)

Registers the dialog module to the OpenSIPS Binary Internal Interface.

Default value is 0 (not registered).

Example 1.44. Set accept_replicated_dialogs parameter

...
modparam("dialog", "accept_replicated_dialogs", 1)
...

1.6.45. replicate_dialogs_to (string)

Adds a new dialog replication destination. The destination will receive all dialog-related events (creation, updating and deletion) over UDP, using the Binary Internal Interface.

Default value is “null” (no replication destinations).

Example 1.45. Set replicate_dialogs_to parameter

...
modparam("dialog", "replicate_dialogs_to", "10.0.0.150:5062")
...

1.6.46. th_callid_passwd (string)

The string password that will be used for encoding/decoding the callid in case of topology_hiding with callid mangling.

Default value is “"OpenSIPS"

Example 1.46. Set th_callid_passwd parameter

...
modparam("dialog", "th_callid_passwd", "my_topo_hiding_secret")
...

1.6.47. th_callid_prefix (string)

The prefix that will be used for detecting callids which have been encoded by the dialog topology hiding. Make sure to change this value in case your SIP path contains multiple OpenSIPS boxes with topology hiding.

Default value is “"DLGCH_"

Example 1.47. Set th_callid_prefix parameter

...
modparam("dialog", "th_callid_prefix", "MYCALLIDPREFIX_")
...

1.6.48. th_passed_contact_uri_params (string)

List of semicolon-separated Contact URI parameters that will be passed from one side to the other for topology hiding calls. To be used when end-to-end functionality uses such Contact URI parameters.

Default value is “empty” - do not pass any parameters

Example 1.48. Set th_passed_contact_uri_params parameter

...
modparam("dialog", "th_passed_contact_uri_params", "paramname1;myparam;custom_param")
...

1.6.49. th_passed_contact_params (string)

List of semicolon-separated Contact header parameters that will be passed from one side to the other for topology hiding calls. To be used when end-to-end functionality uses such Contact header parameters.

Default value is “empty” - do not pass any parameters

Example 1.49. Set th_passed_contact_params parameter

...
modparam("dialog", "th_passed_contact_params", "paramname1;myparam;custom_param")
...

1.7. Exported Functions

1.7.1.  create_dialog()

The function creats the dialog for the currently processed request. The request must be an initial request. Optionally,the function also receives a string parameter, which specifies whether the dialog end-points should be pinged via SIP options messages. The parameter can be "P" to specify to only ping the caller, "p" to only ping the callee or "Pp" to ping both dialog sides. If the extra string parameter is provided and one end-point fails to respond to a options ping, OpenSIPS will terminate the dialog from the middle. The string parameter can also contain "B" to activate the bye on timeout behavior.

The function returns true if the dialog was successfully created or if the dialog was previously created.

This function can be used from REQUEST_ROUTE.

Example 1.50. create_dialog() usage

...
create_dialog();
...
#ping caller
create_dialog("P");
...
#ping caller and callee
create_dialog("Pp");

#bye on timeout
create_dialog("B");
...

1.7.2.  match_dialog()

This function is to be used to match a sequential (in-dialog) request to an existing dialog. In other words, the function will try to match the current request to an known ongoing dialog.

The function tries to use (for dialog matching) the DID (Dialog ID) from Route header and also falls back to SIP-wise matching.

As sequential requests are automatically matched to the dialog when doing "loose_route()" from script, this function is intended to: (A) control the place in your script where the dialog matching is done and (B) to cope with bogus sequential requests that do not have Route headers, so they are not handled by loose_route().

The function returns true if a dialog exists for the request.

This function can be used from REQUEST_ROUTE.

Example 1.51. match_dialog() usage

...
    if (has_totag()) {
        loose_route();
        if ($DLG_status==NULL && !match_dialog() ) {
            xlog(" cannot match request to a dialog \n");
        }
    }
...

1.7.3.  validate_dialog()

The function checks the current received requests against the dialog (internal data) it belongs to. Performing several tests, the function will help to detect the bogus injected in-dialog requests (like malicious BYEs).

The performed tests are related to CSEQ sequence checking and routing information checking (contact and route set).

The function returns true if a dialog exists for the request and if the request is valid (according to dialog data). If the request is invalid, the following return codes are returned :

  • -1 - invalid cseq

  • -2 - invalid remote target

  • -3 - invalid route set

  • -4 - other errors ( parsing, no dlg, etc )

This function can be used from REQUEST_ROUTE.

Example 1.52. validate_dialog() usage

...
    if (has_totag()) {
        loose_route();
        if ($DLG_status!=NULL && !validate_dialog() ) {
            xlog(" in-dialog bogus request \n");
        } else {
            xlog(" in-dialog valid request - $DLG_dir !\n");
        }
    }
...

1.7.4.  fix_route_dialog()

The function forces an in dialog SIP message to contain the ruri, route headers and dst_uri, as specified by the internal data of the dialog it belongs to. The function will prevent the existence of bogus injected in-dialog requests ( like malicious BYEs )

This function can be used from REQUEST_ROUTE.

Example 1.53. fix_route_dialog() usage

...
    if (has_totag()) {
        loose_route();
        if ($DLG_status!=NULL)
            if (!validate_dialog())
                fix_route_dialog();
    }
...

1.7.5.  get_dialog_info(attr,var,key,key_val)

The function extracts a dialog value from another dialog. It first searches through all existing (ongoing) dialogs for a dialog that has a dialog variable named "key" with the value "key_val" (so a dialog where $dlg_val(key)=="key_val"). If found, it returns the value of the dialog variable "attr" from the found dialog in the "var" pseudo-variable, otherwise nothing is written in "var", and a negative error code is returned.

NOTE: the function does not require to be called in the context of a dialog - you can use it whenever / whereever for searching for other dialogs.

Meaning of the parameters is as follows:

  • attr - the name of the dialog variable (from the found dialog) to be returned;

  • var - a pvar where to store the value of the "attr" dialog variable

  • key - name of a dialog variable to be used a search key (when looking after the target dialog)

  • key_val - the value of the dialog variable that is used as key in searching the target dialog.

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

Example 1.54. get_dialog_info usage

...
if ( get_dialog_info("callee","$var(x)","caller","$fu") ) {
	xlog("caller $fU has another ongoing, talking to callee $var(x)\n")
}

# create dialog for current call and place the caller and callee attributes
create_dialog();
$dlg_val(caller) = $fu;
$dlg_val(callee) = $ru;
...

1.7.6.  set_dlg_profile(profile,[value])

Inserts the current dialog into a profile. Note that if the profile does not support values, this will be silently discarded. A dialog may be inserted in the same profile multiple times.

NOTE: the dialog must be created before using this function (use create_dialog() function before).

Meaning of the parameters is as follows:

  • profile - name of the profile to be added to;

  • value (optional) - string value to define the belonging of the dialog to the profile - note that the profile must support values. Pseudo-variables are supported.

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

Example 1.55. set_dlg_profile usage

...
set_dlg_profile("inbound_call");
set_dlg_profile("caller","$fu");
...

1.7.7.  unset_dlg_profile(profile,[value])

Removes the current dialog from a profile.

NOTE: the dialog must be created before using this function (use create_dialog() function before).

Meaning of the parameters is as follows:

  • profile - name of the profile to be removed from;

  • value (optional) - string value to define the belonging of the dialog to the profile - note that the profile must support values. Pseudo-variables are supported.

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

Example 1.56. unset_dlg_profile usage

...
unset_dlg_profile("inbound_call");
unset_dlg_profile("caller","$fu");
...

1.7.8.  is_in_profile(profile,[value])

Checks if the current dialog belongs to a profile. If the profile supports values, the check can be reinforced to take into account a specific value - if the dialog was inserted into the profile for a specific value. If not value is passed, only simply belonging of the dialog to the profile is checked. Note that the profile does not supports values, this will be silently discarded.

NOTE: the dialog must be created before using this function (use create_dialog() function before).

Meaning of the parameters is as follows:

  • profile - name of the profile to be checked against;

  • value (optional) - string value to toughen the check. Pseudo-variables are supported.

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

Example 1.57. is_in_profile usage

...
if (is_in_profile("inbound_call")) {
	log("this request belongs to a inbound call\n");
}
...
if (is_in_profile("caller","XX")) {
	log("this request belongs to a call of user XX\n");
}
...

1.7.9.  get_profile_size(profile,[value],size)

Returns the number of dialogs belonging to a profile. If the profile supports values, the check can be reinforced to take into account a specific value - how many dialogs were inserted into the profile with a specific value. If not value is passed, only simply belonging of the dialog to the profile is checked. Note that the profile does not supports values, this will be silently discarded.

Meaning of the parameters is as follows:

  • profile - name of the profile to get the size for;

  • value (optional) - string value to toughen the check. Pseudo-variables are supported;

  • size - an AVP or script variable to return the profile size in.

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

Example 1.58. get_profile_size usage

...
get_profile_size("inbound_call","$avp(size)");
xlog("currently there are $avp(size) inbound calls\n");
...
get_profile_size("caller","$fu");
xlog("currently, the user %fu has $avp(size) active outgoing calls\n");
...

1.7.10.  set_dlg_flag(idx)

Sets the dialog flag index idx to true. The dialog flags are dialog persistent and they can be accessed (set and test) for all requests belonging to the dialog.

The flag index can be between 0 and 31.

NOTE: the dialog must be created before using this function (use create_dialog() function before).

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

Example 1.59. set_dlg_flag usage

...
set_dlg_flag("3");
...

1.7.11.  test_and_set_dlg_flag(idx, value)

Atomically checks if the dialog flag index idx is equal to value. If true, changes the value with the oppsosite one. This operation is done under the dialog lock.

The flag index can be between 0 and 31.

The value should be 0 (false) or 1 (true).

NOTE: the dialog must be created before using this function (use create_dialog() function before).

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

Example 1.60. test_and_set_dlg_flag usage

...
test_and_set_dlg_flag("3", "0");
...

1.7.12.  reset_dlg_flag(idx)

Resets the dialog flag index idx to false. The dialog flags are dialog persistent and they can be accessed (set and test) for all requests belonging to the dialog.

The flag index can be between 0 and 31.

NOTE: the dialog must be created before using this function (use create_dialog() function before).

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

Example 1.61. reset_dlg_flag usage

...
reset_dlg_flag("16");
...

1.7.13.  is_dlg_flag_set(idx)

Returns true if the dialog flag index idx is set. The dialog flags are dialog persistent and they can be accessed (set and test) for all requests belonging to the dialog.

The flag index can be between 0 and 31.

NOTE: the dialog must be created before using this function (use create_dialog() function before).

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

Example 1.62. is_dlg_flag_set usage

...
if (is_dlg_flag_set("16")) {
	xlog("dialog flag 16 is set\n");
}
...

1.7.14.  store_dlg_value(name,val)

Attaches to the dialog the value val under the name name. The values attached to dialogs are dialog persistent and they can be accessed (read and write) for all requests belonging to the dialog.

Parameter val may contain pseudo-variables.

NOTE: the dialog must be created before using this function (use create_dialog() function before).

Same functionality may be obtain by assigning a value to pseudo variable $dlg_val(name).

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

Example 1.63. store_dlg_value usage

...
store_dlg_value("inv_src_ip","$si");
store_dlg_value("account type","prepaid");
# or
$dlg_val(account_type) = "prepaid";
...

1.7.15.  fetch_dlg_value(name,pvar)

Fetches from the dialog the value of attribute named name. The values attached to dialogs are dialog persistent and they can be accessed (read and write) for all requests belonging to the dialog.

Parameter pvar may be a script var ($var) or and avp ($avp).

NOTE: the dialog must be created before using this function (use create_dialog() function before).

Same functionality may be obtain by reading the pseudo variable $dlg_val(name).

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

Example 1.64. fetch_dlg_value usage

...
fetch_dlg_value("inv_src_ip","$avp(2)");
fetch_dlg_value("account type","$var(account)");
# or
$var(account) = $dlg_val(account_type);
...

1.7.16.  topology_hiding()

Dialog module can also do a small overhead topology hiding. By calling this function on an initial Invite, for the current dialog, the modules will hide the topology, meaning that it will strip and restore all the Via, Record-Route and Route headers and it will replace the contact with the IP address of the interface where the request was received.

You must note however, that the detection of the future in-dialog requests(BYE, reInvite, etc.) for these dialogs on which topology hiding is applied, is not done automatically. Without topology hiding and only normal dialog, the detection was done when loose_route was called. But now, for this dialogs where topology hiding is applied, the in dialog requests reaching OpenSIPS won't have any Route headers and the RURI will point to OpenSIPS machine. So, to be able to match the in-dialog requests to the corresponding dialog, a script function must be called. It's name is match_dialog and you can read it's description above. The in-dialog topology requests are requests with a to tag, RURI pointing to opensips and with a method specific to a Invite dialog. For this kind of requests you should call match_dialog() function. If a dialog is found the function returns success.

The great advantage of using the topology hiding functionality built inside dialog module is that you can use all the dialog modules functionalities: profiles, dialog variables, dialog timeouts, etc..

Optionally,the function also receives a string parameter, which holds string flags. Current options for the string flags are :

  • U - Propagate the Username in the Contact header URI

  • C - Encode the callid header

    There are many cases where propagating the callid towards the callee side is not a good idea, since sometimes the callid contains the IP of the actual caller side, thus revealing part of the network topology.

    When using the "C" flag, the callid will be automatically encoded / decoded, transparent for the script writer - inside OpenSIPS (script,MI functions, etc ) all the variables related to the callid will represent the callid value for the caller side. If the callid for the callee side is needed, refer to the $DLG_callee_callid pvar.

Example 1.65. topology_hiding usage

...
if(!has_totag() && is_method("INVITE")) {
	topology_hiding();
}
...
...
if(!has_totag() && is_method("INVITE")) {
	topology_hiding("U");
}
...

Example 1.66. calling match_dialog() function for topology hiding sequential requests

...
if (has_totag()  && (uri == myself)  && is_method("INVITE|ACK|BYE|UPDATE")
        if(match_dialog())
        {
                xlog(" in-dialog topology hiding request - $DLG_dir\n");
                route(1);
                exit;
        }
}
...

1.8. Exported statistics

1.8.1. active_dialogs

Returns the number of current active dialogs (may be confirmed or not).

1.8.2. early_dialogs

Returns the number of early dialogs.

1.8.3. processed_dialogs

Returns the total number of processed dialogs (terminated, expired or active) from the startup.

1.8.4. expired_dialogs

Returns the total number of expired dialogs from the startup.

1.8.5. failed_dialogs

Returns the number of failed dialogs ( dialogs were never established due to whatever reasons - internal error, negative reply, cancelled, etc )

1.8.6. create_sent

Returns the number of replicated dialog create requests send to other OpenSIPS instances.

1.8.7. update_sent

Returns the number of replicated dialog update requests send to other OpenSIPS instances.

1.8.8. delete_sent

Returns the number of replicated dialog delete requests send to other OpenSIPS instances.

1.8.9. create_recv

Returns the number of dialog create events received from other OpenSIPS instances.

1.8.10. update_recv

Returns the number of dialog update events received from other OpenSIPS instances.

1.8.11. delete_recv

Returns the number of dialog delete events received from other OpenSIPS instances.

1.9. Exported MI Functions

1.9.1. dlg_list

Lists the description of the dialogs (calls). If no paramter is given, all dialogs will be listed. If a dialog identifier is passed as paramter (callid and fromtag), only that dialog will be listed. If a index and conter parameter is passed, it will list only a number of "counter" dialogs starting with index (as offset) - this is used to get only section of dialogs.

Name: dlg_list

Parameters (with dialog idetification):

  • callid (optional) - callid if a single dialog to be listed.

  • from_tag (optional, but cannot be present without the callid paramter) - fromtag (as per initial request) of the dialog to be listed. entry

Parameters (with dialog counting):

  • index - offset where the dialog listing should start.

  • counter - how many dialogs should be listed (starting from the offset)

MI FIFO Command Format:

		:dlg_list:_reply_fifo_file_
		_empty_line_
		
		:dlg_list:_reply_fifo_file_
		abcdrssfrs122444@192.168.1.1
		AAdfeEFF33
		
		:dlg_list:_reply_fifo_file_
		40
		10
		

1.9.2. dlg_list_ctx

The same as the “dlg_list” but including in the dialog description the associated context from modules sitting on top of the dialog module. This function also prints the dialog's values. In case of binary values, the non-printable chars are represented in hex (e.g. \x00)

Name: dlg_list_ctx

Parameters: see “dlg_list

MI FIFO Command Format:

		:dlg_list_ctx:_reply_fifo_file_
		_empty_line_
		

1.9.3. dlg_end_dlg

Terminates an ongoing dialog. If dialog is established, BYEs are sent in both directions. If dialog is in unconfirmed or early state, a CANCEL will be sent to the callee side, that will trigger a 487 from the callee, which, when relayed, will also end the dialog on the caller's side.

Name: dlg_end_dlg

Parameters:

  • h_entry - hash entry of the dialog in the internal dialog table

  • h_id - hash id of the dialog on the hash entry

  • extra_hdrs - (optional) string containg extra headers (full format) to be added to the BYE requests.

The values for the h_entry and h_id can be get via the dlg_list MI command.

MI FIFO Command Format:

		:dlg_end_dlg:_reply_fifo_file_
		342
		56
		_empty_line_
		

1.9.4. profile_get_size

Returns the number of dialogs belonging to a profile. If the profile supports values, the check can be reinforced to take into account a specific value - how many dialogs were inserted into the profile with a specific value. If not value is passed, only simply belonging of the dialog to the profile is checked. Note that the profile does not supports values, this will be silently discarded.

Name: profile_get_size

Parameters:

  • profile - name of the profile to get the value for.

  • value (optional)- string value to toughen the check;

MI FIFO Command Format:

		:profile_get_size:_reply_fifo_file_
		inbound_calls
		_empty_line_
		

1.9.5. profile_list_dlgs

Lists all the dialogs belonging to a profile. If the profile supports values, the check can be reinforced to take into account a specific value - list only the dialogs that were inserted into the profile with that specific value. If not value is passed, all dialogs belonging to the profile will be listed. Note that the profile does not supports values, this will be silently discarded. Also, when using shared profiles using the CacheDB interface, this command will only display the local dialogs.

Name: profile_list_dlgs

Parameters:

  • profile - name of the profile to list the dialog for.

  • value (optional)- string value to toughen the check;

MI FIFO Command Format:

		:profile_list_dlgs:_reply_fifo_file_
		inbound_calls
		_empty_line_
		

1.9.6. profile_get_values

Lists all the values belonging to a profile along with their count. If the profile does not support values a total count will be returned. Note that this function does not work for shared profiles over the CacheDB interface.

Name: profile_get_values

Parameters:

  • profile - name of the profile to list the dialog for.

MI FIFO Command Format:

		:profile_get_values:_reply_fifo_file_
		inbound_calls
		_empty_line_
		

1.9.7. dlg_db_sync

Will synchronize the information about the dialogs from the database with the OpenSIPS internal memory. To be used mainly for transfering OpenSIPS dialog information from one server to another.

Name: dlg_db_sync

It takes no parameters

MI FIFO Command Format:

		:dlg_db_sync:_reply_fifo_file_
		_empty_line_
		

1.9.8. dlg_restore_db

Restores the dialog table after a potential desynchronization event. The table is truncated, then populated with CONFIRMED dialogs from memory.

Name: dlg_restore_db

It takes no parameters

MI FIFO Command Format:

		:dlg_restore_db:_reply_fifo_file_
		_empty_line_
		

1.9.9. list_all_profiles

Lists all the dialog profiles, along with 1 or 0 if the given profile has/does not have an associated value.

Name: list_all_profiles

Parameters: It takes no parameters

MI FIFO Command Format:

		:list_all_profiles:_reply_fifo_file_
		_empty_line_
		

1.10. Exported pseudo-variables

1.10.1. $DLG_count

Returns the number of current active dialogs (may be confirmed or not).

1.10.2. $DLG_status

Returns the status of the dialog corresponding to the processed sequential request. This PV will be available only for sequential requests, after doing loose_route().

Value may be:

  • NULL - Dialog not found.

  • 1 - Dialog unconfirmed (created but no reply received at all)

  • 2 - Dialog in early state (created provisional reply received, but no final reply received yet)

  • 3 - Confirmed by a final reply but no ACK received yet.

  • 4 - Confirmed by a final reply and ACK received.

  • 5 - Dialog ended.

1.10.3. $DLG_lifetime

Returns the duration (in seconds) of the dialog corresponding to the processed sequential request. The duration is calculated from the dialog confirmation and the current moment. This PV will be available only for sequential requests, after doing loose_route().

NULL will be returned if there is no dialog for the request.

1.10.4. $DLG_flags

Returns the dialog flags array (as a single integer value) of the dialog corresponding to the processed sequential request. This PV will be available only for sequential requests, after doing loose_route().

NULL will be returned if there is no dialog for the request.

1.10.5. $DLG_dir

Returns the direction of the request in dialog (as "UPSTREAM" or "DOWNSTREAM" string) - to be used for sequential request. This PV will be available only for sequential requests (on replies), after doing loose_route().

NULL will be returned if there is no dialog for the request.

1.10.6. $DLG_did

Returns the id of the dialog corresponding to the processed sequential request. The output format is entry ':' id (as returned by the dlg_list MI function). This PV will be available only for sequential requests, after doing loose_route().

NULL will be returned if there is no dialog for the request.

1.10.7. $DLG_end_reason

Returns the reason for the dialog termination. It can be one of the following :

  • Upstream BYE - Callee has sent a BYE

  • Downstream BYE - Caller has sent a BYE

  • Lifetime Timeout - Dialog lifetime expired

  • MI Termination - Dialog ended via the MI interface

  • Ping Timeout - Dialog ended because no reply to in-dialog pings

  • RTPProxy Timeout - Media timeout signaled by RTPProxy

NULL will be returned if there is no dialog for the request, or if the dialog is not ended in the current context.

1.10.8. $DLG_timeout

Used to set the dialog lifetime (in seconds). When read, the variable returns the number of seconds until the dialog expires and is destroyed. Note that reading the variable is only possible after the dialog is created (for initial requests) or after doing loose_route() (for sequential requests). Important notice: using this variable with a REALTIME db_mode is very inefficient, because every time the dialog value is changed, a database update is done.

NULL will be returned if there is no dialog for the request, otherwise the number of seconds until the dialog expiration.

1.10.9. $DLG_callee_callid

Read only variable that will contain the callid as it is propagated towards the callee side, in case topology_hiding("C") is called.

NULL will be returned if there is no dialog for the request or if topology_hiding with callid encoding was not used for the current dialog.

1.10.10. $dlg_val(name)

This is a read/write variable that allows access to the dialog attribute named name. This PV will be available only for sequential requests, after doing loose_route().

NULL will be returned if there is no dialog for the request.

1.11. Exported Events

1.11.1.  E_DLG_STATE_CHANGED

This event is raised when the dialog state is changed.

Parameters:

  • ostate - the old state of the dialog.

  • nstate - the new state of the dialog.

Chapter 2. Developer Guide

2.1. Available Functions

2.1.1.  register_dlgcb (dialog, type, cb, param, free_param_cb)

Register a new callback to the dialog.

Meaning of the parameters is as follows:

  • struct dlg_cell* dlg - dialog to register callback to. If maybe NULL only for DLG_CREATED callback type, which is not a per dialog type.

  • int type - types of callbacks; more types may be register for the same callback function; only DLG_CREATED must be register alone. Possible types:

    • DLGCB_LOADED

    • DLGCB_SAVED

    • DLG_CREATED - called when a new dialog is created - it's a global type (not associated to any dialog)

    • DLG_FAILED - called when the dialog was negatively replied (non-2xx) - it's a per dialog type.

    • DLG_CONFIRMED - called when the dialog is confirmed (2xx replied) - it's a per dialog type.

    • DLG_REQ_WITHIN - called when the dialog matches a sequential request - it's a per dialog type.

    • DLG_TERMINATED - called when the dialog is terminated via BYE - it's a per dialog type.

    • DLG_EXPIRED - called when the dialog expires without receiving a BYE - it's a per dialog type.

    • DLGCB_EARLY - called when the dialog is created in an early state (18x replied) - it's a per dialog type.

    • DLGCB_RESPONSE_FWDED - called when the dialog matches a reply to the initial INVITE request - it's a per dialog type.

    • DLGCB_RESPONSE_WITHIN - called when the dialog matches a reply to a subsequent in dialog request - it's a per dialog type.

    • DLGCB_MI_CONTEXT - called when the mi dlg_list_ctx command is invoked - it's a per dialog type.

    • DLGCB_DESTROY

  • dialog_cb cb - callback function to be called. Prototype is: “void (dialog_cb) (struct dlg_cell* dlg, int type, struct dlg_cb_params * params);

  • void *param - parameter to be passed to the callback function.

  • param_free callback_param_free - callback function to be called to free the param. Prototype is: “void (param_free_cb) (void *param);

Chapter 3. Frequently Asked Questions

3.1.

What happend with “use_tight_match” parameter?

The parameter was removed with version 1.3 as the option of tight matching became mandatory and not configurable. Now, the tight matching is done all the time (when using DID matching).

3.2.

What happend with “bye_on_timeout_flag” parameter?

The parameter was removed in a dialog module parameter restructuring. To keep the bye on timeout behavior, you need to provide a "B" string parameter to the create_dialog() function.

3.3.

What happend with “dlg_flag” parameter?

The parameter is considered obsolete. The only way to create a dialog is to call the create_dialog() function

3.4.

Where can I find more about OpenSIPS?

Take a look at http://www.opensips.org/.

3.5.

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 OpenSIPS 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 .

3.6.

How can I report a bug?

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