SERSIP Express Router

1
SER(SIP Express Router)

• Speaker Changyu Wu
• Adviser Quincy Wu
• Date2007/02/07

2
Overview

• Introduction
• Configuration file architecture
• Global parameter
• External module loading
• Module parameters
• Routing blocks
• Example program
• AVPOPS
• Exported Parameters
• Exported Functions
• Conclusion
• Reference

3
Introduction

• SIP Express Router (SER) is a high-performance,
  configurable, free SIP server
• It can act as SIP registrar, proxy or redirect
  server.
• SER s configuration file is divided into four
  main sections.
• Global parameter
• External module loading
• Module parameters
• Routing blocks

4
Configuration file architecture
.. listen163.22.16.33 aliasjohn.ipv6.club
.tw port5060 .. loadmodule
/usr/local/lib/ser/ser/modules/mysql.so loadmodu
le /usr/local/lib/ser/ser/modules/auth_db.so
. mdoparam(auth_db, db_url,
mysql//serpassword_at_localhost/ser) modparam(au
th_db, calculate_ha1, yes) . route if
(!uri163.22.16.33)
. break
Global parameter
External module loading
Module parameters
Routing blocks
/usr/local/etc/ser/ser.cfg (OSFreeBSD5.4)
5
Global parameter

• alias All requests with hostname matching an
  alias will satisfy the condition "urimyself".
• Ex alias ms11.voip.edu.tw
• listen list of all IP addresses or hostnames SER
  should listen on.
• Ex listen163.22.16.40
• port Listens on the specified port (default
  5060).
• Ex port5060

6
External module loading

• loadmodule Specifies a module to be loaded
• loadmodule /path/modules name
• Ex
• loadmodule /usr/local/lib/ser/ser/modules/mysql.s
  o
• loadmodule /usr/local/lib/ser/ser/modules/auth_db
  .so

7
Module parameters

• modparam Module parameter configuration. The
  commands takes three parameters
• module - Module in which the parameter resides.
• parameter - Name of the parameter to be
  configured.
• value - New value of the parameter.
• modparam (module, parameter, value)
• Exmodparam(auth_db, calculate_ha1, yes)

8
Routing blocks

• routenumber... - This marks a "route block"
  in configuration files.
• route blocks are basic building blocks of ser
  scripts.
• route(n), where n is number of the block. The
  action break exits currently executed route
  block.
• route0
• call routing block number 2
• route(2)
• route2
• forward(163.22.16.40", 5060)

9
Conditional statements

• A very useful feature is the ability to make
  routing logic depend on a condition.
• If (urisip0-9._at_ms11.voip.edu.tw)
• Else
• ..

10
Domain matching

• The easiest way to decide whether a request
  belongs a served domain is using the myself
  operand.
• aliasms11.voip.edu.tw"
• route0
• if (urimyself)
• log(1,"request for served domain")
• else
• log(1,"request for outbound domain")
• outbound forwarding
• t_relay()

11
Request URL Rewriting

• SER has the ability to change request URI in many
  ways.
• rewritehost(hostname)
• Exrewritehost(163.22.16.40)
• rewriteuri(uri)
• Exrewriteuri(sipchangyu_at_163.22.16.40)
• If (methodINVITE)
• if(uri(0-9)._at_)
• rewritehost(163.22.20.154)
• forward(urihost,
  uriport)

12
Authentication

• Load auth modules
• loadmodule /usr/local/lib/ser/modules/auth.so
• loadmodule /usr/local/lib/ser/modules/auth_db.so
  
• Module parameters
• modparm(auth_db, calculate_ha1, yes)
• modparm(auth_db, password_column, password)

13
Authentication (cont)

• If (urimyself)
• if (methodREGISTER)
• If (!(www_authorize(ms11.voip.edu.tw,
  subscriber)))
• www_challenge(ms11.voip.edu.tw, 0)
• break
• save(location)
• break
• If (!lookup(location))
• sl_send_reply(404, Not found)

14
Reply message

• sl module
• For the current request, a reply is sent back
  having the given code and text reason.
• sl_send_reply(code, reason)
• Ex If (!lookup(location))
• sl_send_reply(404, Not found)

15
AVPops

• AVPops modules
• Implementing services and preferences per user or
  domain.
• The AVPops module exports functions for
  interfacing DB resources.
• Exported Parameters.
• Exported Functions.

16
Exported Parameters

• avp_url (string)
• modparam("avpops","avp_url","mysql//serpasswd_at_lo
  calhost/ser")
• avp_table (string)
• modparam("avpops","avp_table","subscriber")
• avp_aliases (string)
• modparam("avpops","avp_aliases","uuidi660email
  semail_address")

17
Exported Functions

• avp_db_load(source,name)
• source
• ruri - use information from RURI
• avp_alias - use the content of the AVP (defined
  by alias) as UUID
• name
• which AVPs will be loaded from DB into memory
• Ex
• avp_db_load("ruri","i678")

18
Exported Functions (cont)

• avp_write(value,name)
• Value
• ruri - write RURI
• value - write the value
• Name
• The name of the new written AVP
• avp_write(4762",sphone")

19
Exported Functions (cont)

• avp_pushto(destination,name)
• destination
• ruri
• username
• domain
• name
• The name of the new written AVP
• avp_pushto(ruri/username, sphone)

20
Exported Functions (cont)

• avp_check(name,op_value)
• name
• which AVP(s) should be checked
• op_value
• eq - AVP value equal to value
• lt - AVP value less than value
• gt - AVP value greater than value
• The value can be
• ruri - check against RURI
• from - check against FROM URI
• avp_check("sperson","eq/from/I")

21
Rewrite uri

• route
• avp_db_load(ruri/username, stele)
• avp_write(4762, sphone)
• if (avp_check(stele, eq/sphone/g))
• .
• .

22
Conclusion

• How can configuring SER
• Four main sections
• Routing block design
• How use AVPops module

23
Reference

• SER
• http//www.iptel.org/ser/
• Install SER
• http//ms11.voip.edu.tw/changyu/Technological20f
  ile/20061114_Changyu_SER.ppt
• AVPops modules
• http//www.voice-sistem.ro/docs/avpops/
• Registrar modules
• http//www.openser.org/docs/modules/1.1.x/registra
  r.html
• Auth_db modules
• http//www.openser.org/docs/modules/1.1.x/auth_db.
  html
• sl modules
• http//www.openser.org/docs/modules/1.1.x/sl.html
• RFC2617
• HTTP Authentication Basic and Digest Access
  Authentication