UAC Module

Ramona-Elena Modroiu

   <ramona@rosdev.ro>

Daniel-Constantin Mierla

   <miconda@gmail.com>

Edited by

Ramona-Elena Modroiu

   <ramona@rosdev.ro>

   Copyright © 2009-2010 asipto.com

   Copyright © 2005 Voice Sistem
     __________________________________________________________________

   Table of Contents

   1. Admin Guide

        1. Overview
        2. Dependencies

              2.1. Kamailio Modules
              2.2. External Libraries or Applications

        3. Parameters

              3.1. rr_from_store_param (string)
              3.2. rr_to_store_param (string)
              3.3. restore_mode (string)
              3.4. restore_dlg (int)
              3.5. restore_passwd (string)
              3.6. restore_from_avp (string)
              3.7. restore_to_avp (string)
              3.8. credential (string)
              3.9. auth_realm_avp (string)
              3.10. auth_username_avp (string)
              3.11. auth_password_avp (string)
              3.12. reg_db_url (string)
              3.13. reg_timer_interval (string)
              3.14. reg_retry_interval (int)
              3.15. reg_db_table (string)
              3.16. reg_contact_addr (string)

        4. Functions

              4.1. uac_replace_from(display,uri)
              4.2. uac_replace_from(uri)
              4.3. uac_restore_from()
              4.4. uac_replace_to(display,uri)
              4.5. uac_replace_to(uri)
              4.6. uac_restore_to()
              4.7. uac_auth()
              4.8. uac_req_send()
              4.9. uac_reg_lookup(uuid, dst)
              4.10. uac_reg_request_to(user, mode)

        5. Exported pseudo-variables
        6. Remote Registration

   List of Examples

   1.1. Set rr_from_store_param parameter
   1.2. Set rr_to_store_param parameter
   1.3. Set restore_mode parameter
   1.4. Set restore_dlg parameter
   1.5. Set restore_passwd parameter
   1.6. Set restore_from_avp parameter
   1.7. Set restore_to_avp parameter
   1.8. Set credential parameter
   1.9. Set auth_realm_avp parameter
   1.10. Set auth_username_avp parameter
   1.11. Set auth_password_avp parameter
   1.12. Set reg_db_url parameter
   1.13. Set reg_timer_inteval parameter
   1.14. Set reg_retry_interval parameter
   1.15. Set reg_db_table parameter
   1.16. Set reg_contact_addr parameter
   1.17. uac_replace_from usage
   1.18. uac_replace_from usage
   1.19. uac_restore_from usage
   1.20. uac_replace_to usage
   1.21. uac_replace_to usage
   1.22. uac_restore_to usage
   1.23. uac_auth usage
   1.24. uac_req_send usage
   1.25. uac_reg_lookup usage
   1.26. uac_reg_request_to usage
   1.27. lookup remote registrations usage

Chapter 1. Admin Guide

   Table of Contents

   1. Overview
   2. Dependencies

        2.1. Kamailio Modules
        2.2. External Libraries or Applications

   3. Parameters

        3.1. rr_from_store_param (string)
        3.2. rr_to_store_param (string)
        3.3. restore_mode (string)
        3.4. restore_dlg (int)
        3.5. restore_passwd (string)
        3.6. restore_from_avp (string)
        3.7. restore_to_avp (string)
        3.8. credential (string)
        3.9. auth_realm_avp (string)
        3.10. auth_username_avp (string)
        3.11. auth_password_avp (string)
        3.12. reg_db_url (string)
        3.13. reg_timer_interval (string)
        3.14. reg_retry_interval (int)
        3.15. reg_db_table (string)
        3.16. reg_contact_addr (string)

   4. Functions

        4.1. uac_replace_from(display,uri)
        4.2. uac_replace_from(uri)
        4.3. uac_restore_from()
        4.4. uac_replace_to(display,uri)
        4.5. uac_replace_to(uri)
        4.6. uac_restore_to()
        4.7. uac_auth()
        4.8. uac_req_send()
        4.9. uac_reg_lookup(uuid, dst)
        4.10. uac_reg_request_to(user, mode)

   5. Exported pseudo-variables
   6. Remote Registration

1. Overview

   The UAC (User Agent Client) module provides some basic UAC
   functionalities like sending SIP requests, registering with a remote
   service, From: header manipulation (anonymization) and client
   authentication.

   The UAC module also supports sending a SIP request from the
   configuration file. See variable $uac_req(name) and the function
   uac_req_send().

   In addition, the module supports database-driven SIP registration
   functionality. See the uac_reg_lookup() function and dedicated section
   for remote registration configuration.

   Known limitations in this version:
     * Authentication does not support qop auth-int, just qop auth;
     * CSeq is not increased during authentication - the response may be
       rejected.
     * The “uac_replace_*” functions can only be run once on the same SIP
       request. Try to save needed changes in a pseudovariable and apply
       them once.

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:
     * TM - Transaction Module
     * RR - Record-Route Module, but only if restore mode for From: URI is
       set to “auto”.
     * Dialog Module, but only if restore mode for From: URI is set to
       “auto” and you want uac_replace_from or uac_replace_to to store the
       values of the URIs as dialog variables.

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. rr_from_store_param (string)
   3.2. rr_to_store_param (string)
   3.3. restore_mode (string)
   3.4. restore_dlg (int)
   3.5. restore_passwd (string)
   3.6. restore_from_avp (string)
   3.7. restore_to_avp (string)
   3.8. credential (string)
   3.9. auth_realm_avp (string)
   3.10. auth_username_avp (string)
   3.11. auth_password_avp (string)
   3.12. reg_db_url (string)
   3.13. reg_timer_interval (string)
   3.14. reg_retry_interval (int)
   3.15. reg_db_table (string)
   3.16. reg_contact_addr (string)

3.1. rr_from_store_param (string)

   Name of Record-Route header parameter that will be used to store an
   encoded version of the original FROM URI.

   This parameter is optional, it's default value being “vsf”.

   Example 1.1. Set rr_from_store_param parameter
...
modparam("uac","rr_from_store_param","my_param")
...

3.2. rr_to_store_param (string)

   Name of Record-Route header parameter that will be used to store
   (encoded) the original TO URI.

   This parameter is optional, it's default value being “vst”.

   Example 1.2. Set rr_to_store_param parameter
...
modparam("uac","rr_to_store_param","my_param")
...

3.3. restore_mode (string)

   There are 3 modes of restoring the original FROM URI and the original
   TO URI:
     * “none” - no information about original URI is stored; restoration
       is not possible.
     * “manual” - all following replies will be restored, but not also the
       sequential requests - this must be manually updated based on
       original URI.
     * “auto” - all sequential requests and replies will be automatically
       updated based on stored original URI. For this option you have to
       set “modparam("rr", "append_fromtag", 1)”.

   This parameter is optional, it's default value being “auto”.

   Example 1.3. Set restore_mode parameter
...
modparam("uac","restore_mode","auto")
...

3.4. restore_dlg (int)

   If set to 1, the module uses dialog variables to store initial and new
   values for From/To headers. The Dialog module has to be loaded and all
   calls that involve changes to From/To headers must be tracked.

   Default value of this parameter is 0.

   Example 1.4. Set restore_dlg parameter
...
modparam("uac", "restore_dlg", 1)
...

3.5. restore_passwd (string)

   String password to be used to encrypt the RR storing parameters. If
   empty, no encryption will be used.

   Default value of this parameter is empty.

   Example 1.5. Set restore_passwd parameter
...
modparam("uac","restore_passwd","my_secret_passwd")
...

3.6. restore_from_avp (string)

   If defined and restore_mode is manual or auto, the avp is used to save
   the original from uri in order to be able to restore it in replies.
   That makes sense, if the original-uri can not be extracted from the
   original request, e.g. if msg_apply_changes() was used after calling
   uac_replace_from() or uac_replace_to().

   If you create a dialog ( with dlg_manage() ) before calling
   uac_replace_from(), this avp will not be needed. The values of the uris
   will be stored as dialog variables.

   Default value of this parameter is empty.

   Example 1.6. Set restore_from_avp parameter
...
modparam("uac","restore_from_avp","$avp(original_uri_from)")
...

3.7. restore_to_avp (string)

   If defined and restore_mode is manual or auto, the avp is used to save
   the original To URI in order to be able to restore it in replies. That
   makes sense if the original-uri can not be extracted from the original
   request, e.g. if msg_apply_changes() was used after calling
   uac_replace_to()

   If you create a dialog ( with dlg_manage() ) before calling or
   uac_replace_to(), this avp will not be needed. The values of the uris
   will be stored as dialog variables.

   Default value of this parameter is empty.

   Example 1.7. Set restore_to_avp parameter
...
modparam("uac","restore_to_avp","$avp(original_uri_to)")
...

3.8. credential (string)

   Contains a multiple definition of credentials used to perform
   authentication.

   This parameter is required if UAC authentication is used.

   Example 1.8. Set credential parameter
...
modparam("uac","credential","username:domain:password")
...

3.9. auth_realm_avp (string)

   The definition of an PV that might contain the realm to be used to
   perform authentication.

   When the PV value is an empty string or NULL when uac_auth() is called,
   the realm is taken from the reply and only username matching is done.
   This can be used if the realm upstream will be using is not known in
   advance.

   If you define it, you also need to define “auth_username_avp”
   (Section 3.10, “auth_username_avp (string)”) and “auth_username_avp”
   (Section 3.11, “auth_password_avp (string)”).

   Example 1.9. Set auth_realm_avp parameter
...
modparam("uac","auth_realm_avp","$avp(i:10)")
...

3.10. auth_username_avp (string)

   The definition of an AVP that might contain the username to be used to
   perform authentication.

   If you define it, you also need to define “auth_realm_avp”
   (Section 3.9, “auth_realm_avp (string)”) and “auth_username_avp”
   (Section 3.11, “auth_password_avp (string)”).

   Example 1.10. Set auth_username_avp parameter
...
modparam("uac","auth_username_avp","$avp(i:11)")
...

3.11. auth_password_avp (string)

   The definition of an AVP that might contain the password to be used to
   perform authentication.

   If you define it, you also need to define “auth_password_avp”
   (Section 3.11, “auth_password_avp (string)”) and “auth_username_avp”
   (Section 3.11, “auth_password_avp (string)”).

   Example 1.11. Set auth_password_avp parameter
...
modparam("uac","auth_password_avp","$avp(i:12)")
...

3.12. reg_db_url (string)

   DB URL to fetch account profiles for registration.

   Example 1.12. Set reg_db_url parameter
...
modparam("uac", "reg_db_url",
    "mysql://kamailio:kamailiorw@localhost/kamailio")
...

3.13. reg_timer_interval (string)

   Timer interval (in seconds) at which registrations are managed, e.g.
   renewed as needed.

   The default value is 90 seconds.

   Example 1.13. Set reg_timer_inteval parameter
...
modparam("uac", "reg_timer_interval", 60)
...

3.14. reg_retry_interval (int)

   Failed registration attempts will be retried after this interval (in
   seconds). The interval is not exact, retries may be attempted as much
   as reg_timer_interval secs earlier. If set to 0, failed registrations
   will be disabled permanently.

   The default value is 0 sec (disabled)

   Example 1.14. Set reg_retry_interval parameter
...
modparam("uac", "reg_retry_interval", 300)
...

3.15. reg_db_table (string)

   DB table name to fetch user profiles for registration.

   This parameter is optional, it's default value being “uacreg”.

   Example 1.15. Set reg_db_table parameter
...
modparam("uac", "reg_db_table", "uacreg")
...

3.16. reg_contact_addr (string)

   Address to be used to build contact address. Must be at least host
   part, can have port and parameters. Must not include 'sip:'. The
   username part of the Contact: URI will be the L_UUID field in the
   database.

   Example 1.16. Set reg_contact_addr parameter
...
modparam("uac", "reg_contact_addr", "192.168.1.2:5080")
...

4. Functions

   4.1. uac_replace_from(display,uri)
   4.2. uac_replace_from(uri)
   4.3. uac_restore_from()
   4.4. uac_replace_to(display,uri)
   4.5. uac_replace_to(uri)
   4.6. uac_restore_to()
   4.7. uac_auth()
   4.8. uac_req_send()
   4.9. uac_reg_lookup(uuid, dst)
   4.10. uac_reg_request_to(user, mode)

4.1.  uac_replace_from(display,uri)

   Replace in FROM header the display name and the URI part.

   display and URI parameters can include pseudo-variables.

   This function can be used from REQUEST_ROUTE and from BRANCH_ROUTE.

   NOTE: Previous versions of this function added double quotes
   automatically to display variable. That is no longer the case, if you
   expect that behavior, you will have to add the quotes by yourself.

   If you set restore_mode to AUTO, the URI will be modified automatically
   in all subsequent requests and replies in that dialog.

   There are two ways in which the AUTO mode can be achieved.

   One uses the rr module and appends to the Record-Route header a
   parameter containing some strings from which the original and new URI
   can be computed. The problem with this mode is that it relies on the
   fact the parties will send the Route exactly as it was received. In
   case there is a change, the resulting URIs will not be correct.

   The other one uses the dialog module to store the original and new URI.
   If you already use dialog module in your configuration, this is the
   advisable mode. All you need to do to use this is to call dlg_manage()
   before calling uac_replace_from(). It works by storing the URIs as
   dialog variables and registering callbacks in dialog module for in
   dialog requests.

   Example 1.17. uac_replace_from usage
...
# replace both display and uri
uac_replace_from("$avp(s:display)","$avp(s:uri)");
# replace only display and do not touch uri
uac_replace_from("batman","");   # display is replaced with: batman
uac_replace_from("\"batman\"","");  # display is replaced with: "batman"
# remove display and replace uri
uac_replace_from("","sip:robin@gotham.org");
# remove display and do not touch uri
uac_replace_from("","");
...

4.2.  uac_replace_from(uri)

   Replace in FROM header the URI part without altering the display name.

   URI parameter can include pseudo-variables.

   This function can be used from REQUEST_ROUTE and from BRANCH_ROUTE.

   Example 1.18. uac_replace_from usage
...
uac_replace_from("sip:batman@gotham.org");
...

4.3.  uac_restore_from()

   This function will check if the FROM URI was modified and will use the
   information stored in header parameter to restore the original FROM URI
   value.

   This function can be used from REQUEST_ROUTE.

   Example 1.19. uac_restore_from usage
...
uac_restore_from();
...

4.4.  uac_replace_to(display,uri)

   Replace in TO header the display name and the URI part.

   display and URI parameters can include pseudo-variables.

   This function can be used from REQUEST_ROUTE and from BRANCH_ROUTE.

   NOTE: Previous versions of this function added double quotes
   automatically to display variable. That is no longer the case, if you
   expect that behavior, you will have to add the quotes by yourself.

   Example 1.20. uac_replace_to usage
...
# replace both display and uri
uac_replace_to("$avp(display)","$avp(uri)");
# replace only display and do not touch uri
uac_replace_to("batman","");   # display is replaced with: batman
uac_replace_to("\"batman\"","");  # display is replaced with: "batman"
# remove display and replace uri
uac_replace_to("","sip:robin@gotham.org");
# remove display and do not touch uri
uac_replace_to("","");
...

4.5.  uac_replace_to(uri)

   Replace in TO header the URI part without altering the display name.

   URI parameter can include pseudo-variables.

   This function can be used from REQUEST_ROUTE and from BRANCH_ROUTE.

   If you set restore_mode to AUTO, the URI will be modified automatically
   in all subsequent requests and replies in that dialog.

   There are two ways in which the AUTO mode can be achieved.

   One uses the rr module and appends to the Record-Route header a
   parameter containing some strings from which the original and new URI
   can be computed. The problem with this mode is that it relies on the
   fact the parties will send the Route exactly as it was received. In
   case there is a change, the resulting URIs will not be correct.

   The other one uses the dialog module to store the original and new URI.
   If you already use dialog module in your configuration, this is the
   advisable mode. All you need to do to use this is to call dlg_manage()
   before calling uac_replace_to(). It works by storing the URIs as dialog
   variables and registering callbacks in dialog module for in dialog
   requests.

   Example 1.21. uac_replace_to usage
...
uac_replace_to("sip:batman@gotham.org");
...

4.6.  uac_restore_to()

   This function will check if the TO URI was modified and will use the
   information stored in header parameter to restore the original TO URI
   value.

   This function can be used from REQUEST_ROUTE.

   Example 1.22. uac_restore_to usage
...
uac_restore_to();
...

4.7.  uac_auth()

   This function can be called only from failure route and will build the
   authentication response header and insert it into the request without
   sending anything.

   This function can be used from FAILURE_ROUTE.

   Example 1.23. uac_auth usage
...
uac_auth();
...

4.8.  uac_req_send()

   This function sends a SIP message from the configuration file. The
   message is built out of $uac_req(...) pseudo-variable.

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

   Example 1.24. uac_req_send usage
...
$uac_req(method)="OPTIONS";
$uac_req(ruri)="sip:kamailio.org";
$uac_req(furi)="sip:kamailio.org";
$uac_req(turi)="sip:kamailio.org";
$uac_req(callid)=$(mb{s.md5});
uac_req_send();
...

4.9.  uac_reg_lookup(uuid, dst)

   This function sets the PV dst to SIP URI that correspond to uuid in uac
   registations table. uuid and dst must be pseudo-variables.

   This function can be used from ANY_ROUTE.

   Example 1.25. uac_reg_lookup usage
...

if(uac_reg_lookup("$rU", "$ru"))
{
    lookup("location");
}
...

4.10.  uac_reg_request_to(user, mode)

   This function can be used to send an authenticated request to a remote
   user in the uac registrations table. It sets the request-uri, dst-uri
   and auth_*_avp pv's to the values that correspond to the supplied user.

   The mode indicates whether the user should match the local uuid
   (mode=0), or the username (mode=1).

   The auth_*_avp module parameters must be set to valid pv's.

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

   Example 1.26. uac_reg_request_to usage
...

if(uac_reg_request_to("$fU", 0))
{
        xlog("L_NOTICE", "Found remote user [$rU] on [$rd] via [$du]");
        t_on_failure("REMOTE_AUTH");

        t_relay()
}
...
failure_route[REMOTE_AUTH] {
        if ($T_reply_code == 401 or $T_reply_code == 407) {
                xlog("L_NOTICE", "Remote asked for authentication");
                uac_auth()
        }
}
...

5. Exported pseudo-variables

     * $uac_req(key)

   Exported pseudo-variables are documented at
   http://www.kamailio.org/wiki/.

6. Remote Registration

   The module can register contact addresses to remote REGISTRAR servers.
   You have to add records to uacreg table. The table stores following
   attributes:
     * l_uuid - local unique user id, e.g.,: 12345678

     * l_username - local user name, e.g.,: test

     * l_domain - local domain, e.g.,: mysipserver.com

     * r_username - remote username, e.g.,: test123

     * r_domain - remote domain, e.g.,: sipprovider.com

     * realm - remote relam, e.g.,: sipprovider.com

     * auth_username - authentication username, e.g.,: test123

     * auth_password - authentication password, e.g.,: xxxxxx

     * auth_proxy - SIP address of authentication proxy, e.g.,:
       sip:sipprovider.com

     * expires - expiration time for registration, in seconds, e.g.,: 360

   The module takes care of sending REGISTER and refresh registrations
   before they expire.

   When calls come in, you have to run uac_reg_lookup() that will detect
   if the call is coming from a remote SIP provider and can change the
   R-URI to local username@domain. Afterwards you can run location lookup.

   Example 1.27. lookup remote registrations usage
...
    if(uac_reg_lookup("$rU", "$ru")) {
        xlog("request from a remote SIP provider [$ou => $ru]\n");
    }
    lookup("location");
...
