cplc Module

Bogdan-Andrei Iancu

   Voice Sistem SRL

Edited by

Bogdan-Andrei Iancu

Frederic Gaisnon

   <frederic.gaisnon@gmail.com>

   Copyright © 2003 FhG FOKUS

   Copyright © 2021 MomentTech
     __________________________________________________________________

   Table of Contents

   1. Admin Guide

        1. Overview
        2. Dependencies

              2.1. Kamailio Modules
              2.2. External Libraries or Applications

        3. Parameters

              3.1. db_url (string)
              3.2. db_table (string)
              3.3. username_column (string)
              3.4. domain_column (string)
              3.5. cpl_xml_column (string)
              3.6. cpl_bin_column (string)
              3.7. cpl_dtd_file (string)
              3.8. log_dir (string)
              3.9. proxy_recurse (int)
              3.10. proxy_route (string)
              3.11. case_sensitive (int)
              3.12. realm_prefix (string)
              3.13. timer_avp (string)
              3.14. lookup_domain (string)
              3.15. lookup_append_branches (int)
              3.16. use_domain (integer)
              3.17. redirect_route (string)
              3.18. ignore3xx (integer)

        4. Functions

              4.1. cpl_run_script(type,mode, [uri])
              4.2. cpl_process_register()
              4.3. cpl_process_register_norpl()

        5. RPC Commands

              5.1. cpl.load
              5.2. cpl.remove
              5.3. cpl.get

        6. Installation and Running

              6.1. Database setup

   List of Examples

   1.1. Set db_url parameter
   1.2. Set db_table parameter
   1.3. Set username_column parameter
   1.4. Set domain_column parameter
   1.5. Set cpl_xml_column parameter
   1.6. Set cpl_bin_column parameter
   1.7. Set cpl_dtd_file parameter
   1.8. Set log_dir parameter
   1.9. Set proxy_recurse parameter
   1.10. Set proxy_route parameter
   1.11. Set case_sensitive parameter
   1.12. Set realm_prefix parameter
   1.13. Set timer_avp parameter
   1.14. Set lookup_domain parameter
   1.15. Set lookup_append_branches parameter
   1.16. Set use_domain parameter
   1.17. Set redirect_route parameter
   1.18. Set ignore3xx parameter
   1.19. cpl_run_script usage
   1.20. cpl_process_register usage
   1.21. cpl_process_register_norpl 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. db_url (string)
        3.2. db_table (string)
        3.3. username_column (string)
        3.4. domain_column (string)
        3.5. cpl_xml_column (string)
        3.6. cpl_bin_column (string)
        3.7. cpl_dtd_file (string)
        3.8. log_dir (string)
        3.9. proxy_recurse (int)
        3.10. proxy_route (string)
        3.11. case_sensitive (int)
        3.12. realm_prefix (string)
        3.13. timer_avp (string)
        3.14. lookup_domain (string)
        3.15. lookup_append_branches (int)
        3.16. use_domain (integer)
        3.17. redirect_route (string)
        3.18. ignore3xx (integer)

   4. Functions

        4.1. cpl_run_script(type,mode, [uri])
        4.2. cpl_process_register()
        4.3. cpl_process_register_norpl()

   5. RPC Commands

        5.1. cpl.load
        5.2. cpl.remove
        5.3. cpl.get

   6. Installation and Running

        6.1. Database setup

1. Overview

   cplc modules implements a CPL (Call Processing Language) interpreter.
   Support for uploading/downloading/removing scripts via SIP REGISTER
   method is present.

   CPL is an IETF specification detailed in RFC3880
   (https://tools.ietf.org/html/rfc3880).

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:
     * any DB module- a DB module for interfacing the DB operations
       (modules like mysql, postgres, dbtext, etc)
     * TM (Transaction) module- used for proxying/forking requests
     * SL (StateLess) module - used for sending stateless reply when
       responding to REGISTER request or for sending back error responses
     * USRLOC (User Location) module - used for implementing
       lookup("registration") tag (adding into location set of the users'
       contact)

2.2. External Libraries or Applications

   The following libraries or applications must be installed before
   running Kamailio with this module loaded:
     * libxml2 and libxml2-devel - on some SO, these to packages are
       merged into libxml2. This library contains an engine for XML
       parsing, DTD validation and DOM manipulation.

3. Parameters

   3.1. db_url (string)
   3.2. db_table (string)
   3.3. username_column (string)
   3.4. domain_column (string)
   3.5. cpl_xml_column (string)
   3.6. cpl_bin_column (string)
   3.7. cpl_dtd_file (string)
   3.8. log_dir (string)
   3.9. proxy_recurse (int)
   3.10. proxy_route (string)
   3.11. case_sensitive (int)
   3.12. realm_prefix (string)
   3.13. timer_avp (string)
   3.14. lookup_domain (string)
   3.15. lookup_append_branches (int)
   3.16. use_domain (integer)
   3.17. redirect_route (string)
   3.18. ignore3xx (integer)

3.1. db_url (string)

   A SQL URL have to be given to the module for knowing where the database
   containing the table with CPL scripts is locates. If required a user
   name and password can be specified for allowing the module to connect
   to the database server.

   Default value is “mysql://kamailio:kamailiorw@localhost/kamailio”.

   Example 1.1. Set db_url parameter
...
modparam("cplc","db_url","dbdriver://username:password@dbhost/dbname")
...

3.2. db_table (string)

   Indicates the name of the table that store the CPL scripts. This table
   must be locate into the database specified by “db_url” parameter. For
   more about the format of the CPL table please see the
   modules/cplc/init.mysql file.

   Default value is “cpl”.

   Example 1.2. Set db_table parameter
...
modparam("cplc","cpl_table","cpl")
...

3.3. username_column (string)

   Indicates the name of the column used for storing the username.

   Default value is “username”.

   Example 1.3. Set username_column parameter
...
modparam("cplc","username_column","username")
...

3.4. domain_column (string)

   Indicates the name of the column used for storing the domain.

   Default value is “domain”.

   Example 1.4. Set domain_column parameter
...
modparam("cplc","domain_column","domain")
...

3.5. cpl_xml_column (string)

   Indicates the name of the column used for storing the XML version of
   the cpl script.

   Default value is “cpl_xml”.

   Example 1.5. Set cpl_xml_column parameter
...
modparam("cplc","cpl_xml_column","cpl_xml")
...

3.6. cpl_bin_column (string)

   Indicates the name of the column used for storing the binary version of
   the cpl script (compiled version).

   Default value is “cpl_bin”.

   Example 1.6. Set cpl_bin_column parameter
...
modparam("cplc","cpl_bin_column","cpl_bin")
...

3.7. cpl_dtd_file (string)

   Points to the DTD file describing the CPL grammar. The file name may
   include also the path to the file. This path can be absolute or
   relative (be careful the path will be relative to the starting
   directory of Kamailio).

   This parameter is MANDATORY!

   Example 1.7. Set cpl_dtd_file parameter
...
modparam("cplc","cpl_dtd_file","/etc/kamailio/cpl-06.dtd")
...

3.8. log_dir (string)

   Points to a directory where should be created all the log file
   generated by the LOG CPL node. A log file per user will be created (on
   demand) having the name username.log.

   If this parameter is absent, the logging will be disabled without
   generating error on execution.

   Example 1.8. Set log_dir parameter
...
modparam("cplc","log_dir","/var/log/kamailio/cpl")
...

3.9. proxy_recurse (int)

   Tells for how many time is allow to have recurse for PROXY CPL node If
   it has value 2, when doing proxy, only twice the proxy action will be
   re-triggered by a redirect response; the third time, the proxy
   execution will end by going on REDIRECTION branch. The recurse feature
   can be disable by setting this parameter to 0

   Default value of this parameter is 0.

   Example 1.9. Set proxy_recurse parameter
...
modparam("cplc","proxy_recurse",2)
...

3.10. proxy_route (string)

   Before doing proxy (forward), a script route can be executed. This
   parameter indicates the name of the route called. All modifications
   made by that route will be reflected only for the current branch.

   Default value of this parameter is NULL (none).

   Example 1.10. Set proxy_route parameter
...
modparam("cplc","proxy_route","CPL_PROXY")
...

3.11. case_sensitive (int)

   Tells if the username matching should be perform case sensitive or not.
   Set it to a non zero value to force a case sensitive handling of
   usernames.

   Default value of this parameter is 0.

   Example 1.11. Set case_sensitive parameter
...
modparam("cplc","case_sensitive",1)
...

3.12. realm_prefix (string)

   Defines a prefix for the domain part which should be ignored in
   handling users and scripts.

   Default value of this parameter is empty string.

   Example 1.12. Set realm_prefix parameter
...
modparam("cplc","realm_prefix","sip.")
...

3.13. timer_avp (string)

   Full specification (ID, NAME, ALIAS) of the AVP to be used to set the
   value of the Final Response INVITE timeout - it's used by the TIMEOUT
   attribute from the PROXY tag.

   NOTE: take care and synchronize this value with the similar parameters
   in TM module.

   Default value of this parameter is NULL.

   Example 1.13. Set timer_avp parameter
...
modparam("cplc","timer_avp","$avp(i:14)")
...

3.14. lookup_domain (string)

   Used by lookup tag to indicate where to perform user location.
   Basically this is the name of the usrloc domain (table) where the user
   registrations are kept.

   If set to empty string, the lookup node will be disabled - no user
   location will be performed.

   Default value of this parameter is NULL.

   Example 1.14. Set lookup_domain parameter
...
modparam("cplc","lookup_domain","location")
...

3.15. lookup_append_branches (int)

   Tells if the lookup tag should append branches (to do parallel forking)
   if user_location lookup returns more than one contact. Set it to a non
   zero value to enable parallel forking for location lookup tag.

   Default value of this parameter is 0.

   Example 1.15. Set lookup_append_branches parameter
...
modparam("cplc","lookup_append_branches",1)
...

3.16. use_domain (integer)

   Indicates if the domain part of the URI should be used in user
   identification (otherwise only username part will be used).

   Default value is “0 (disabled)”.

   Example 1.16. Set use_domain parameter
...
modparam("cplc","use_domain",1)
...

3.17. redirect_route (string)

   Before doing redirect (deflection), a script route can be executed.
   This parameter indicates the name of the route called. All
   modifications made by that route will be reflected only for the current
   branch.

   Default value of this parameter is NULL (none).

   Example 1.17. Set redirect_route parameter
...
modparam("cplc","redirect_route", "CPL_REDIRECT")
...

3.18. ignore3xx (integer)

   Indicates if 3xx SIP response must be ignored.

   Default value is “0 (disabled)”.

   Example 1.18. Set ignore3xx parameter
...
modparam("cplc","ignore3xx",1)
...

4. Functions

   4.1. cpl_run_script(type,mode, [uri])
   4.2. cpl_process_register()
   4.3. cpl_process_register_norpl()

4.1.  cpl_run_script(type,mode, [uri])

   Starts the execution of the CPL script. The user name is fetched from
   new_uri or requested uri or from To header -in this order- (for
   incoming execution) or from FROM header (for outgoing execution).
   Regarding the stateful/stateless message processing, the function is
   very flexible, being able to run in different modes (see below
   the"mode" parameter). Normally this function will end script execution.
   There is no guaranty that the CPL script interpretation ended when
   Kamailio script ended also (for the same INVITE ;-)) - this can happen
   when the CPL script does a PROXY and the script interpretation pause
   after proxying and it will be resume when some reply is received (this
   can happen in a different process of SER). If the function returns to
   script, the SIP server should continue with the normal behavior as if
   no script existed. When some error is returned, the function itself
   haven't sent any SIP error reply (this can be done from script).

   Meaning of the parameters is as follows:
     * type - which part of the script should be run; set it to "incoming"
       for having the incoming part of script executed (when an INVITE is
       received) or to "outgoing" for running the outgoing part of script
       (when a user is generating an INVITE - call).
     * mode - sets the interpreter mode as stateless/stateful behavior.
       The following modes are accepted:
          + IS_STATELESS - the current INVITE has no transaction created
            yet. All replies (redirection or deny) will be done is a
            stateless way. The execution will switch to stateful only when
            proxy is done. So, if the function returns, will be in
            stateless mode.
          + IS_STATEFUL - the current INVITE has already a transaction
            associated. All signaling operations (replies or proxy) will
            be done in stateful way.So, if the function returns, will be
            in stateful mode.
          + FORCE_STATEFUL - the current INVITE has no transaction created
            yet. All signaling operations will be done is a stateful way
            (on signaling, the transaction will be created from within the
            interpreter). So, if the function returns, will be in
            stateless mode.
       HINT: is_stateful is very difficult to manage from the routing
       script (script processing can continue in stateful mode);
       is_stateless is the fastest and less resources consumer
       (transaction is created only if proxying is done), but there is
       minimal protection against retransmissions (since replies are send
       stateless); force_stateful is a good compromise - all signaling is
       done stateful (retransmission protection) and in the same time, if
       returning to script, it will be in stateless mode (easy to continue
       the routing script execution)
     * uri - optional - provide the SIP URI to be used for loading the CPL
       script, instead of taking it from R-URI or headers.

   This function can be used from REQUEST_ROUTE.

   Example 1.19. cpl_run_script usage
...
cpl_run_script("incoming","force_stateful");
...

4.2.  cpl_process_register()

   This function MUST be called only for REGISTER requests. It checks if
   the current REGISTER request is related or not with CPL script
   upload/download/ remove. If it is, all the needed operation will be
   done. For checking if the REGISTER is CPL related, the function looks
   fist to "Content-Type" header. If it exists and has a the mime type set
   to "application/cpl+xml" means this is a CPL script upload/remove
   operation. The distinction between to case is made by looking at
   "Content-Disposition" header; id its value is "script;action=store",
   means it's an upload; if it's "script;action=remove", means it's a
   remove operation; other values are considered to be errors. If no
   "Content-Type" header is present, the function looks to "Accept" header
   and if it contains the "*" or "application/cpl-xml" the request it will
   be consider one for downloading CPL scripts. The functions returns to
   script only if the REGISTER is not related to CPL. In other case, the
   function will send by itself the necessary replies (stateless - using
   sl), including for errors.

   This function can be used from REQUEST_ROUTE.

   Example 1.20. cpl_process_register usage
...
if (method=="REGISTER") {
    cpl_process_register();
}
...

4.3.  cpl_process_register_norpl()

   Same as “cpl_process_register” without internally generating the reply.
   All information (script) is appended to the reply but without sending
   it out.

   Main purpose of this function is to allow integration between CPL and
   UserLocation services via same REGISTER messages.

   This function can be used from REQUEST_ROUTE.

   Example 1.21. cpl_process_register_norpl usage
...
if (method=="REGISTER") {
    cpl_process_register();
    # continue with usrloc part
    save("location");
}
...

5. RPC Commands

   5.1. cpl.load
   5.2. cpl.remove
   5.3. cpl.get

5.1. cpl.load

   For the given user, loads the XML cpl file, compiles it into binary
   format and stores both format into database.

   Name: cpl.load

   Parameters:
     * username : name of the user
     * cpl_filename: file name

   RPC Command format:
...
kamcmd cpl.load username cpl_filename
...

5.2. cpl.remove

   For the given user, removes the entire database record (XML cpl and
   binary cpl); user with empty cpl scripts are not accepted.

   Name: cpl.remove

   Parameters:
     * username : name of the user

   RPC Command format:
...
kamcmd cpl.remove username
...

5.3. cpl.get

   For the given user, returns the CPL script in XML format.

   Name: cpl.get

   Parameters:
     * username : name of the user

   RPC Command format:
...
kamcmd cpl.get username
...

6. Installation and Running

   6.1. Database setup

6.1. Database setup

   Before running Kamailio with cplc, you have to setup the database table
   where the module will store the CPL scripts. For that, if the table was
   not created by the installation script or you choose to install
   everything by yourself you can use the cpc-create.sql SQL script in the
   database directories in the kamailio/scripts folder as template.
   Database and table name can be set with module parameters so they can
   be changed, but the name of the columns must be as they are in the SQL
   script. You can also find the complete database documentation on the
   project webpage,
   https://www.kamailio.org/docs/db-tables/kamailio-db-devel.html.
