pipelimit Module

Daniel-Constantin Mierla

Hendrik Scholz

Edited by

Daniel-Constantin Mierla

   Copyright © 2010 Asipto.com

   Copyright © 2006 Freenet Cityline GmbH
     __________________________________________________________________

   Table of Contents

   1. Admin Guide

        1. Overview
        2. Dependencies

              2.1. Kamailio Modules
              2.2. External Libraries or Applications

        3. Exported Parameters

              3.1. db_url (string)
              3.2. plp_table_name (string)
              3.3. plp_pipeid_column (string)
              3.4. plp_limit_column (string)
              3.5. plp_algorithm_column (string)
              3.6. timer_interval (integer)
              3.7. reply_code (integer)
              3.8. reply_reason (string)

        4. Exported Functions

              4.1. pl_check(name)
              4.2. pl_drop([ [min ], max ])

        5. Exported MI Functions

              5.1. pl_stats
              5.2. pl_set_pipe
              5.3. pl_get_pipes
              5.4. pl_set_pid
              5.5. pl_get_pid
              5.6. pl_push_load

   List of Examples

   1.1. Set db_url parameter
   1.2. Set plp_table_name parameter
   1.3. Set plp_pipeid_column parameter
   1.4. Set plp_limit_column parameter
   1.5. Set plp_algorithm_column parameter
   1.6. Set timer_interval parameter
   1.7. Set reply_code parameter
   1.8. Set reply_code parameter at runtime
   1.9. Set reply_reason parameter
   1.10. Set reply_reason parameter at runtime
   1.11. rl_check usage
   1.12. pl_drop usage

Chapter 1. Admin Guide

   Table of Contents

   1. Overview
   2. Dependencies

        2.1. Kamailio Modules
        2.2. External Libraries or Applications

   3. Exported Parameters

        3.1. db_url (string)
        3.2. plp_table_name (string)
        3.3. plp_pipeid_column (string)
        3.4. plp_limit_column (string)
        3.5. plp_algorithm_column (string)
        3.6. timer_interval (integer)
        3.7. reply_code (integer)
        3.8. reply_reason (string)

   4. Exported Functions

        4.1. pl_check(name)
        4.2. pl_drop([ [min ], max ])

   5. Exported MI Functions

        5.1. pl_stats
        5.2. pl_set_pipe
        5.3. pl_get_pipes
        5.4. pl_set_pid
        5.5. pl_get_pid
        5.6. pl_push_load

1. Overview

   This module implements traffic limiting for SIP requests.

   The module defines in an abstract mode the notion of 'pipe', which can
   be a link to an IP address, to a network or a trunk. The associtiation
   of traffic to a pipe is done in the config file, therefore, a pipe
   could represent SIP traffic coming from a user or the flow of specific
   SIP requests such as INVITE or REGISTER.

   Pipelimit started from ratelimit module, adding support for definition
   of pipes limits in database and dynamic names. Complexity of keeping
   everything in a module and make it dual mode functional resulted in a
   new module which is focused on just traffic shaping policies. For
   description of the algorithms see the README of ratelimit.

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:
     * database connection module.

2.2. External Libraries or Applications

   The following libraries or applications must be installed before
   running Kamailio with this module loaded:
     * None.

3. Exported Parameters

   3.1. db_url (string)
   3.2. plp_table_name (string)
   3.3. plp_pipeid_column (string)
   3.4. plp_limit_column (string)
   3.5. plp_algorithm_column (string)
   3.6. timer_interval (integer)
   3.7. reply_code (integer)
   3.8. reply_reason (string)

3.1. db_url (string)

   URL of the database server to be used.

   Default value is "mysql://openser:openserrw@localhost/openser".

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

3.2. plp_table_name (string)

   Name of DB table where data definition for pipes is stores.

   Default value is "pl_pipes".

   Example 1.2. Set plp_table_name parameter
...
modparam("pipelimit", "plp_table_name", "mypipes")
...

3.3. plp_pipeid_column (string)

   Name of 'pipeid' column.

   Default value is "pipeid".

   Example 1.3. Set plp_pipeid_column parameter
...
modparam("pipelimit", "plp_pipeid_column", "name")
...

3.4. plp_limit_column (string)

   Name of 'limit' column.

   Default value is "limit".

   Example 1.4. Set plp_limit_column parameter
...
modparam("pipelimit", "plp_limit_column", "name")
...

3.5. plp_algorithm_column (string)

   Name of 'algorithm' column.

   Default value is "algorithm".

   Example 1.5. Set plp_algorithm_column parameter
...
modparam("pipelimit", "plp_algorithm_column", "name")
...

3.6. timer_interval (integer)

   The initial length of a timer interval in seconds. All amounts of
   messages have to be divided by this timer to get a messages per second
   value.

   IMPORTANT: A too small value may lead to performance penalties due to
   timer process overloading.

   Default value is 10.

   Example 1.6. Set timer_interval parameter
...
modparam("ratelimit", "timer_interval", 5)
...

3.7. reply_code (integer)

   The code of the reply sent by Kamailio while limiting.

   Default value is 503.

   Example 1.7. Set reply_code parameter
...
modparam("ratelimit", "reply_code", 505)
...

   This value can be modified at runtime using sercmd

   Example 1.8.  Set reply_code parameter at runtime
sercmd cfg.set_now_int ratelimit reply_code 505

3.8. reply_reason (string)

   The reason of the reply sent by Kamailio while limiting.

   Default value is "Server Unavailable".

   Example 1.9. Set reply_reason parameter
...
modparam("ratelimit", "reply_reason", "Limiting")
...

   This value can be modified at runtime using sercmd

   Example 1.10.  Set reply_reason parameter at runtime
sercmd cfg.set_now_string ratelimit reply_reason "Limiting"

4. Exported Functions

   4.1. pl_check(name)
   4.2. pl_drop([ [min ], max ])

4.1. pl_check(name)

   Check the current request against the 'name' pipe. The pipe name can be
   provided via a pseudo variabile.

   The method will return an error code if the limit for the matched
   algorithm is reached.

   Meaning of the parameters is as follows:
     * name - the pseudovariable holding the pipe name.

   This function can be used from REQUEST_ROUTE.

   Example 1.11. rl_check usage
...
        # perform pipe match for current method
        if (!pl_check("one")) {
                pl_drop();
                exit;
        }
...
        # use pipe 'one' for the current method via PV
        $var(p) = "one";
        if (!pl_check("$var(p)")) {
                pl_drop();
                exit;
        }
...

4.2. pl_drop([ [min ], max ])

   For the current request, a "503 - Server Unavailable" reply is sent
   back. The reply may or may not have a "Retry-After" header. If no
   parameter is given, there will be no "Retry-After" header. If only the
   max parameter is given, the reply will contain a "Retry-After: max"
   header. If both min and max params are given, the reply will contain a
   "Retry-After: random" header with random being a random value between
   the given min and max.

   Meaning of the parameters is as follows:
     * min - the minimum value of "Retry-After" header.
     * max - the maximum value of "Retry-After" header.

   This function can be used from REQUEST_ROUTE.

   Example 1.12. pl_drop usage
...
        if (!pl_check("one")) {
                # send back a "503 - Server Unavailable"
                # with a "Retry-After: 5"
                pl_drop("5");
                exit;
        }
...

5. Exported MI Functions

   5.1. pl_stats
   5.2. pl_set_pipe
   5.3. pl_get_pipes
   5.4. pl_set_pid
   5.5. pl_get_pid
   5.6. pl_push_load

5.1. pl_stats

   Lists the parameters and variabiles in the pipelimit module.

   Name: pl_stats

   Parameters: none

   MI FIFO Command Format:
                :pl_stats:_reply_fifo_file_
                _empty_line_

5.2. pl_set_pipe

   Sets the pipe parameters for the given pipe id.

   Name: pl_set_pipe

   Parameters:
     * pipe_id - pipe id.
     * pipe_algorithm - the algorithm assigned to the given pipe id.
     * pipe_limit - the limit assigned to the given pipe id.

   MI FIFO Command Format:
                :pl_set_pipe:_reply_fifo_file_
                2
                RED
                10
                _empty_line_

5.3. pl_get_pipes

   Gets the list of in use pipes.

   Name: pl_get_pipes

   Parameters: none

   MI FIFO Command Format:
                :pl_get_pipes:_reply_fifo_file_
                _empty_line_

5.4. pl_set_pid

   Sets the PID Controller parameters for the Feedback Algorithm.

   Name: pl_set_pid

   Parameters:
     * ki - the integral parameter.
     * kp - the proportional parameter.
     * kd - the derivative parameter.

   MI FIFO Command Format:
                :pl_set_pid:_reply_fifo_file_
                0.5
                0.5
                0.5
                _empty_line_

5.5. pl_get_pid

   Gets the list of in use PID Controller parameters.

   Name: pl_get_pid

   Parameters: none

   MI FIFO Command Format:
                :pl_get_pid:_reply_fifo_file_
                _empty_line_

5.6. pl_push_load

   Force the value of the load parameter. This command is useful for
   testing the Feedback algorithm.

   Name: pl_push_load

   Parameters:
     * load - the forced value of load (it must be greater then 0.0 and
       smaller then 1.0).

   MI FIFO Command Format:
                :pl_push_load:_reply_fifo_file_
                0.85
                _empty_line_
