Kamailio™ (former OpenSER) is an Open Source SIP Server released under GPL.
Kamailio primarily acts as a SIP server for VOIP and telecommunications platforms under various roles and can handle load of hight CPS ( Calls per second ) with custom call routing logic with the help of scripts .
IMS extensions for VoLTE; ENUM; DID and least cost routing; load balancing; routing fail-over; Json and XMLRPC control interface, SNMP monitoring.
Features
It can work as Registrar or Location server. For SIP call logic it can become a Proxy or SIP Application server . Can also act like an Redirect , Dispatcher or simply a SIP over websocket server.
- Kamailio is Customisable to suit business requirement and scale .
It can be embedded to devices as the binary file is small size. Additional modules can be appended for more functions with the same core.
Due to its modular architecture – core, internal libraries , module interface and ability to extend functionality with scripts such as LUA , Kamailio can be readily integrated to a VOIP ecosystem.
- Call routing and control functionality
Offers stateless and transactional stateful SIP Proxy processing ( suited for inbound gateways ) and serial and parallel forking.
Also NAT traversal support for SIP and RTP traffic ( suited to be WebRTC server )
Among other features it offers load balancing with many distribution algorithms and failover support , flexible least cost routing , routing failover and replication for High Availability (HA).
Can be readily integrated with external databases , caches, notification system ( SNS , APNS , GCM ), voip monitors , CDR processors, API systems etc for efficient call processing.
- Transport Layers supported
- UDP, TCP, TLS and SCTP
- IPv4 and IPv6
- gateways via (IPv4 to IPv6, UDP to TLS, a.s.o.)
- SCTP multi-homing and multi-streaming
- WebSocket for WebRTC
- Asynchronous TCP, UDP and SCTP,
asynchronous SIP message processing and inter-process message queues communication system
- Secure Communication ( TLS + AAA)
- Digest SIP User authentication
- Authorization via ACL or group membership
- IP and Network authentication
- TLS support for SIP signaling
- transparent handling of SRTP for secure audio
- TLS domain name extension support
- authentication and authorization against database (MySQL, PostgreSQL, UnixODBC, BerkeleyDB, Oracle, text files), RADIUS and DIAMETER
- IP and DNS
- support for SRV and NAPTR DNS lookups
- SRV DNS failover
- DNSsec support
- ENUM support
- internal DNS caching system – avoid DNS blocking
- IP level Blacklists
- multi-homed and multi-domain support
- topology hiding – hide IP addresses in SIP headers to protect your network architecture
- Accounting
Kamailio gives event based and configurable accounting data details. Can show multi-leg call accounting ( A leg to B leg ). It can store to database, Radius or Diameter based on module used . Has a prepaid engine.
text-based management interface via FIFO file, udp, xmlrpc and unix sockets.
RPC control interface – via XMLRPC, UDP or TCP
- Rich Communication Services (RCS)
- SIP SIMPLE Presence Server (rich presence)
- Presence User Agent ( SUBSCRIBE , NOTIFY and PUBLSH)
- XCAP client capabilities and Embedded XCAP Server
- Presence DialogInfo support – SLA/BLA
- Instant Messaging ( IM)
- Embedded MSRP relay
- Monitoring and Troubleshooting
Support for SNMP – interface to Simple Network Management Protocol. For Debugging it has config debugger , remote control via XMLRPC and error message logging system .Provides internal statistics exported via RPC and SNMP.
The supported one are Perl , Java SIP Servlet Application Interface , Lua , Managed Code (C#) , Python
- Multiple Database Backends
(MySQL, PostgreSQL, SQLite, UnixODBC, BerkeleyDB, Oracle, text files) and other database types which have unixodbc drivers. ‘
It can have connections pool and different backends be used at same time (e.g., accounting to Oracle and authorization against MySQL).
Has connectors for Memcached, Redis , MongoDB and Cassandra no-SQL backends
Acts as SIP to PSTN gateway and gateway to sms or xmpp and other IM services. Has Interoperability with SIP enabled devices and applications such as SIP phones (Snom, Cisco, etc.), Media Servers (Asterisk, FreeSwitch, etc.)
- IMS
- diameter support and authentication
- I-CSCF, P-CSCF, S-CSCF
- charging, QOS, ISC
- Miscellaneous
- CPL – Call Processing Language (RFC3880)
- Internal generic caching system
- Memcached connector
- Redis NoSQL database connector
- CLI – kamctl and sercmd
- Web Management Interface: Siremis
- SIP-T and SIP-I
- music on hold queue
- message body compression/decompression (gzip-deflate)
- Extensive documentation for both administrators and developers
Scalability:
- Kamailio can run on embedded systems, with limited resources – the performances can be up to hundreds of call setups per second
- used as load balancer in stateless mode, Kamailio can handle over 5000 call setups per second
- on systems with 4GB memory, Kamailio can serve a population over 300 000 online subscribers
- system can easily scale by adding more Kamailio servers
- Kamailio can be used in geographic distributed VoIP platforms
- Kamailio least-cost-routing scales up to millions of routing rules
- straightforward failover and redundancy
Start Kamalio
service kamailo start
Logs
tail -f /var/log/kamailio
To Check if Kamailio instance is running
>ps -ax | grep “kamailio”
57411 ? S 0:01 /usr/sbin/kamailio -f /etc/kamailio/kamailio.cfg -P /var/run/kamailio/kamailio.pid -m 4096 -M 128 -u root -g root
Configuration
Kamctlrc
The Kamailio configuration file for the control tools. Can set variables used in the kamctl and kamdbctl setup scripts. Per default all variables here are commented out, the control tools will use their internal default values. This file lets to edit SIP domain, the database engine, username/password/ to connect to database, etc.
## your SIP domain
SIP_DOMAIN=13.126.169.58
## chrooted directory
# $CHROOT_DIR="/path/to/chrooted/directory"
## database type: MYSQL, PGSQL, ORACLE, DB_BERKELEY, DBTEXT, or SQLITE
# by default none is loaded
# If you want to setup a database with kamdbctl, you must at least specify this parameter.
DBENGINE=MYSQL
## database host
# DBHOST=localhost
## database host
# DBPORT=3306
## database name (for ORACLE this is TNS name)
# DBNAME=kamailio
# database path used by dbtext, db_berkeley or sqlite
# DB_PATH="/usr/local/etc/kamailio/dbtext"
database read/write user
# DBRWUSER="kamailio"
## password for database read/write user
# DBRWPW="kamailiorw"
database read only user
# DBROUSER="kamailioro"
## password for database read only user
# DBROPW="kamailioro"
## database access host (from where is kamctl used)
# DBACCESSHOST=192.168.0.1
database super user (for ORACLE this is ‘scheme-creator’ user)
# DBROOTUSER="root"
## password for database super user
## - important: this is insecure, targeting the use only for automatic testing
## - known to work for: mysql
# DBROOTPW="dbrootpw"
## database character set (used by MySQL when creating database)
#CHARSET="latin1"
## user name column
# USERCOL="username"
# SQL definitions
# If you change this definitions here, then you must change them
# in db/schema/entities.xml too.
# FIXME
# FOREVER="2030-05-28 21:32:15"
# DEFAULT_Q="1.0"
# Program to calculate a message-digest fingerprint
# MD5="md5sum"
# awk tool
# AWK="awk"
# gdb tool
# GDB="gdb"
# If you use a system with a grep and egrep that is not 100% gnu grep compatible,
# e.g. solaris, install the gnu grep (ggrep) and specify this below.
grep tool
# GREP="grep"
# egrep tool
# EGREP="egrep"
# sed tool
# SED="sed"
# tail tool
# LAST_LINE="tail -n 1"
# expr tool
# EXPR="expr"
Describe what additional tables to install. Valid values for the variables below are yes/no/ask. With ask (default) it will interactively ask the user for an answer, while yes/no allow for automated, unassisted installs.
#If to install tables for the modules in the EXTRA_MODULES variable.
# INSTALL_EXTRA_TABLES=ask
# If to install presence related tables.
# INSTALL_PRESENCE_TABLES=ask
# If to install uid modules related tables.
# INSTALL_DBUID_TABLES=ask
Define what module tables should be installed.
If you use the postgres database and want to change the installed tables, then you must also adjust the STANDARD_TABLES or EXTRA_TABLES variable accordingly in the kamdbctl.base script.
standard modules
# STANDARD_MODULES="
standard acc lcr domain group permissions registrar usrloc msilo
alias_db uri_db speeddial avpops auth_db pdt dialog dispatcher
dialplan"
extra modules
# EXTRA_MODULES="
imc cpl siptrace domainpolicy carrierroute userblacklist htable purple sca"
type of aliases used: DB - database aliases; UL - usrloc aliases
- default: none , ALIASES_TYPE="DB"
control engine: RPCFIFO
- default RPCFIFO
CTLENGINE="RPCFIFO"
## path to FIFO file for engine RPCFIFO
# RPCFIFOPATH="/var/run/kamailio/kamailio_rpc_fifo"
## check ACL names; default on (1); off (0)
# VERIFY_ACL=1
## ACL names - if VERIFY_ACL is set, only the ACL names from below list are accepted
# ACL_GROUPS="local ld int voicemail free-pstn"
## check if user exists (used by some commands such as acl);
## - default on (1); off (0)
# VERIFY_USER=1
## verbose - debug purposes - default '0'
# VERBOSE=1
## do (1) or don't (0) store plaintext passwords
## in the subscriber table - default '1'
# STORE_PLAINTEXT_PW=0
Kamailio START Options
PID file path – default is: /var/run/kamailio/kamailio.pid
# PID_FILE=/var/run/kamailio/kamailio.pid
Extra start options – default is: not set
# example: start Kamailio with 64MB share memory: STARTOPTIONS="-m 64"
# STARTOPTIONS=
Kamailio.cfg
config files are used to customize and deploy SIP services since each and every SIP packet is route based on policies specified in conf file ( routing blocks ). Location when installed from source – /usr/local/etc/kamailio/kamailio.cfg , when installed from package – /etc/kamailio/kamailio.cfg
The features in config file :-
Kamailio doesn’t have user authentication by default , so to enable it one must
#!define WITH_MYSQL
#!define WITH_AUTH
kamdbctl tool is to be used for creating and managing the database.
kamdbctl create
Kamctl is used for adding subscriber information and password.
kamctl add altanai1 123
mysql: [Warning] Using a password on the command line interface can be insecure.
MySQL password for user 'kamailio@localhost':
mysql: [Warning] Using a password on the command line interface can be insecure.
new user 'altanai1' added
More details in Tools section below .
#!define WITH_USRLOCDB
requires RTP proxy for RTP relay . NAT traversal support can be set by
#!define WITH_NAT
-
short dialing on server
-
multiple identities (aliases) for subscribers
-
multi-domain support
-
routing to a PSTN gateway
-
routing to a voicemail server
-
TLS encryption
-
instant messaging (pager mode with MESSAGE requests)
-
presence services
Kamailio (OpenSER) SIP Server v4.3- default configuration script
Several features can be enabled using ‘#!define WITH_FEATURE’ directives:
To run in debug mode: define WITH_DEBUG
To enable mysql: define WITH_MYSQL
To enable authentication execute: enable mysql and define WITH_AUTH
To enable IP authentication execute: enable mysql , enable authentication , define WITH_IPAUTH and add IP addresses with group id ‘1’ to ‘address’ table
To enable persistent user location execute:
enable mysql
define WITH_USRLOCDB
To enable presence server execute:
enable mysql
define WITH_PRESENCE
To enable nat traversal execute:
define WITH_NAT
install RTPProxy: http://www.rtpproxy.org
start RTPProxy:
rtpproxy -l your_public_ip -s udp:localhost:7722
option for NAT SIP OPTIONS keepalives: WITH_NATSIPPING
To enable PSTN gateway routing execute:
define WITH_PSTN
set the value of pstn.gw_ip
check route[PSTN] for regexp routing condition
To enable database aliases lookup execute:
enable mysql
define WITH_ALIASDB
To enable speed dial lookup execute:
enable mysql
define WITH_SPEEDDIAL
To enable multi-domain support execute:
enable mysql
define WITH_MULTIDOMAIN
To enable TLS support execute:
adjust CFGDIR/tls.cfg as needed
define WITH_TLS
To enable XMLRPC support execute:
define WITH_XMLRPC
adjust route[XMLRPC] for access policy
To enable anti-flood detection execute:
adjust pike and htable=>ipban settings as needed (default is block if more than 16 requests in 2 seconds and ban for 300 seconds)
define WITH_ANTIFLOOD
To block 3XX redirect replies execute:
define WITH_BLOCK3XX
To enable VoiceMail routing execute:
define WITH_VOICEMAIL
set the value of voicemail.srv_ip
adjust the value of voicemail.srv_port
To enhance accounting execute:
enable mysql
define WITH_ACCDB
add following columns to database
define WITH_MYSQL
define WITH_AUTH
define WITH_USRLOCDB
#!ifdef ACCDB_COMMENT
ALTER TABLE acc ADD COLUMN src_user VARCHAR(64) NOT NULL DEFAULT ”;
ALTER TABLE acc ADD COLUMN src_domain VARCHAR(128) NOT NULL DEFAULT ”;
ALTER TABLE acc ADD COLUMN src_ip varchar(64) NOT NULL default ”;
ALTER TABLE acc ADD COLUMN dst_ouser VARCHAR(64) NOT NULL DEFAULT ”;
ALTER TABLE acc ADD COLUMN dst_user VARCHAR(64) NOT NULL DEFAULT ”;
ALTER TABLE acc ADD COLUMN dst_domain VARCHAR(128) NOT NULL DEFAULT ”;
ALTER TABLE missed_calls ADD COLUMN src_user VARCHAR(64) NOT NULL DEFAULT ”;
ALTER TABLE missed_calls ADD COLUMN src_domain VARCHAR(128) NOT NULL DEFAULT ”;
ALTER TABLE missed_calls ADD COLUMN src_ip varchar(64) NOT NULL default ”;
ALTER TABLE missed_calls ADD COLUMN dst_ouser VARCHAR(64) NOT NULL DEFAULT ”;
ALTER TABLE missed_calls ADD COLUMN dst_user VARCHAR(64) NOT NULL DEFAULT ”;
ALTER TABLE missed_calls ADD COLUMN dst_domain VARCHAR(128) NOT NULL DEFAULT ”;
#!endif
####### Include Local Config If Exists #########
import_file “kamailio-local.cfg”
####### Defined Values #########
# *** Value defines - IDs used later in config
#!ifdef WITH_MYSQL
# - database URL - used to connect to database server by modules such
# as: auth_db, acc, usrloc, a.s.o.
#!ifndef DBURL
#!define DBURL "mysql://kamailio:kamailiorw@localhost/kamailio"
#!endif
#!endif
#!ifdef WITH_MULTIDOMAIN
# - the value for 'use_domain' parameters
#!define MULTIDOMAIN 1
#!else
#!define MULTIDOMAIN 0
#!endif
# - flags
# FLT_ - per transaction (message) flags
# FLB_ - per branch flags
#!define FLT_ACC 1
#!define FLT_ACCMISSED 2
#!define FLT_ACCFAILED 3
#!define FLT_NATS 5
#!define FLB_NATB 6
#!define FLB_NATSIPPING 7
#!substdef "!MY_IP_ADDR!172.31.26.179!g"
#!substdef "!MY_DOMAIN!13.126.169.58!g"
#!substdef "!MY_WS_PORT!8080!g"
#!substdef "!MY_WSS_PORT!4443!g"
#!substdef "!MY_WS_ADDR!tcp:MY_IP_ADDR:MY_WS_PORT!g"
#!substdef "!MY_WSS_ADDR!tls:MY_IP_ADDR:MY_WSS_PORT!g"
#!define WITH_WEBSOCKETS
####### Global Parameters #########
LOG Levels: 3=DBG, 2=INFO, 1=NOTICE, 0=WARN, -1=ERR
#!ifdef WITH_DEBUG
debug=4
log_stderror=yes
#!else
debug=2
log_stderror=no
#!endif
memdbg=5
memlog=5
log_facility=LOG_LOCAL0
fork=yes
children=4
disable TCP (default on)
#disable_tcp=yes
enable_sctp = 0
disable the auto discovery of local aliases based on reverse DNS on IPs (default on)
#auto_aliases=no
add local domain aliases
#alias="sip.mydomain.com"
bind on a specific interface/port/proto (default bind on all available)
#listen=udp:10.0.0.10:5060
port to listen to – can be specified more than once if needed to listen on many ports
port=5060
#!ifdef WITH_TLS
enable_tls=yes
#!endif
life time of TCP connection when there is no traffic – a bit higher than registration expires to cope with UA behind NAT
tcp_connection_lifetime=3605
listen=MY_IP_ADDR
#!ifdef WITH_WEBSOCKETS
listen=MY_WS_ADDR
#!ifdef WITH_TLS
listen=MY_WSS_ADDR
#!endif
#!endif
tcp_connection_lifetime=3604
tcp_accept_no_cl=yes
tcp_rd_buf_size=16384
#And comment line:
#tcp_connection_lifetime=3605
####### Custom Parameters #########
These parameters can be modified runtime via RPC interface , see the documentation of ‘cfg_rpc’ module.
Format: group.id = value ‘desc’ description
Access: $sel(cfg_get.group.id) or @cfg_get.group.id
#!ifdef WITH_PSTN
# PSTN GW Routing
# - pstn.gw_ip: valid IP or hostname as string value, example:
# pstn.gw_ip = "10.0.0.101" desc "My PSTN GW Address"
# - by default is empty to avoid misrouting
pstn.gw_ip = "" desc "PSTN GW Address"
pstn.gw_port = "" desc "PSTN GW Port"
#!endif
#!ifdef WITH_VOICEMAIL
# VoiceMail Routing on offline, busy or no answer
# - by default Voicemail server IP is empty to avoid misrouting
voicemail.srv_ip = "" desc "VoiceMail IP Address"
voicemail.srv_port = "5060" desc "VoiceMail Port"
#!endif
####### Modules Section ########
# set paths to location of modules (to sources or installation folders)
#!ifdef WITH_SRCPATH
mpath="modules/"
#!else
mpath="/usr/lib/x86_64-linux-gnu/kamailio/modules/"
#!endif
#!ifdef WITH_MYSQL
loadmodule "db_mysql.so"
#!endif
loadmodule "mi_fifo.so"
loadmodule "kex.so"
loadmodule "corex.so"
loadmodule "tm.so"
loadmodule "tmx.so"
loadmodule "sl.so"
loadmodule "rr.so"
loadmodule "pv.so"
loadmodule "maxfwd.so"
loadmodule "usrloc.so"
loadmodule "registrar.so"
loadmodule "textops.so"
loadmodule "siputils.so"
loadmodule "xlog.so"
loadmodule "sanity.so"
loadmodule "ctl.so"
loadmodule "cfg_rpc.so"
loadmodule "mi_rpc.so"
loadmodule "acc.so"
#!ifdef WITH_AUTH
loadmodule "auth.so"
loadmodule "auth_db.so"
#!ifdef WITH_IPAUTH
loadmodule "permissions.so"
#!endif
#!endif
#!ifdef WITH_ALIASDB
loadmodule "alias_db.so"
#!endif
#!ifdef WITH_SPEEDDIAL
loadmodule "speeddial.so"
#!endif
#!ifdef WITH_MULTIDOMAIN
loadmodule "domain.so"
#!endif
#!ifdef WITH_PRESENCE
loadmodule "presence.so"
loadmodule "presence_xml.so"
#!endif
#!ifdef WITH_NAT
loadmodule "nathelper.so"
loadmodule "rtpproxy.so"
#!endif
#!ifdef WITH_TLS
loadmodule "tls.so"
#!endif
#!ifdef WITH_ANTIFLOOD
loadmodule "htable.so"
loadmodule "pike.so"
#!endif
#!ifdef WITH_XMLRPC
loadmodule "xmlrpc.so"
#!endif
#!ifdef WITH_DEBUG
loadmodule "debugger.so"
#!endif
#!ifdef WITH_WEBSOCKETS
loadmodule "xhttp.so"
#loadmodule "websocket.so"
loadmodule "nathelper.so"
#!endif
setting module-specific parameters
# ----- mi_fifo params -----
#modparam("mi_fifo", "fifo_name", "/var/run/kamailio/kamailio_fifo")
# ----- ctl params -----
#modparam("ctl", "binrpc", "unix:/var/run/kamailio/kamailio_ctl")
# ----- tm params -----
# auto-discard branches from previous serial forking leg
modparam("tm", "failure_reply_mode", 3)
# default retransmission timeout: 30sec
modparam("tm", "fr_timer", 30000)
# default invite retransmission timeout after 1xx: 120sec
modparam("tm", "fr_inv_timer", 120000)
# ----- rr params -----
# set next param to 1 to add value to ;lr param (helps with some UAs)
modparam("rr", "enable_full_lr", 0)
# do not append from tag to the RR (no need for this script)
modparam("rr", "append_fromtag", 0)
registrar params
modparam("registrar", "method_filtering", 1)
/* uncomment the next line to disable parallel forking via location */
# modparam("registrar", "append_branches", 0)
/* uncomment the next line not to allow more than 10 contacts per AOR */
#modparam("registrar", "max_contacts", 10)
# max value for expires of registrations
modparam("registrar", "max_expires", 3600)
# set it to 1 to enable GRUU
modparam("registrar", "gruu_enabled", 0)
acc params
/* what special events should be accounted ? /
modparam(“acc”, “early_media”, 0)
modparam(“acc”, “report_ack”, 0)
modparam(“acc”, “report_cancels”, 0)
/ by default ww do not adjust the direct of the sequential requests.
if you enable this parameter, be sure the enable “append_fromtag”
in “rr” module /
modparam(“acc”, “detect_direction”, 0)
/ account triggers (flags) /
modparam(“acc”, “log_flag”, FLT_ACC)
modparam(“acc”, “log_missed_flag”, FLT_ACCMISSED)
modparam(“acc”, “log_extra”,
“src_user=$fU;src_domain=$fd;src_ip=$si;”
“dst_ouser=$tU;dst_user=$rU;dst_domain=$rd”)
modparam(“acc”, “failed_transaction_flag”, FLT_ACCFAILED)
/ enhanced DB accounting */
#!ifdef WITH_ACCDB
modparam(“acc”, “db_flag”, FLT_ACC)
modparam(“acc”, “db_missed_flag”, FLT_ACCMISSED)
modparam(“acc”, “db_url”, DBURL)
modparam(“acc”, “db_extra”,
“src_user=$fU;src_domain=$fd;src_ip=$si;”
“dst_ouser=$tU;dst_user=$rU;dst_domain=$rd”)
#!endif
usrloc params – enable DB persistency for location entries
#!ifdef WITH_USRLOCDB
modparam(“usrloc”, “db_url”, DBURL)
modparam(“usrloc”, “db_mode”, 2)
modparam(“usrloc”, “use_domain”, MULTIDOMAIN)
#!endif
auth_db params
#!ifdef WITH_AUTH
modparam(“auth_db”, “db_url”, DBURL)
modparam(“auth_db”, “calculate_ha1”, yes)
modparam(“auth_db”, “password_column”, “password”)
modparam(“auth_db”, “load_credentials”, “”)
modparam(“auth_db”, “use_domain”, MULTIDOMAIN)
permissions params
#!ifdef WITH_IPAUTH
modparam(“permissions”, “db_url”, DBURL)
modparam(“permissions”, “db_mode”, 1)
#!endif
#!endif
alias_db params
#!ifdef WITH_ALIASDB
modparam(“alias_db”, “db_url”, DBURL)
modparam(“alias_db”, “use_domain”, MULTIDOMAIN)
#!endif
speeddial params
#!ifdef WITH_SPEEDDIAL
modparam(“speeddial”, “db_url”, DBURL)
modparam(“speeddial”, “use_domain”, MULTIDOMAIN)
#!endif
domain params
#!ifdef WITH_MULTIDOMAIN
modparam(“domain”, “db_url”, DBURL)
register callback to match myself condition with domains list
modparam(“domain”, “register_myself”, 1)
#!endif
#!ifdef WITH_PRESENCE
presence params
modparam(“presence”, “db_url”, DBURL)
presence_xml params
modparam(“presence_xml”, “db_url”, DBURL)
modparam(“presence_xml”, “force_active”, 1)
#!endif
#!ifdef WITH_NAT
rtpproxy params
modparam(“rtpproxy”, “rtpproxy_sock”, “udp:127.0.0.1:7722”)
nathelper params
modparam(“nathelper”, “natping_interval”, 30)
modparam(“nathelper”, “ping_nated_only”, 1)
modparam(“nathelper”, “sipping_bflag”, FLB_NATSIPPING)
modparam(“nathelper”, “sipping_from”, “sip:pinger@kamailio.org”)
params needed for NAT traversal in other modules
modparam(“nathelper|registrar”, “received_avp”, “$avp(RECEIVED)”)
modparam(“usrloc”, “nat_bflag”, FLB_NATB)
#!endif
tls params
#!ifdef WITH_TLS
modparam(“tls”, “config”, “/etc/kamailio/tls.cfg”)
#!endif
pike params
#!ifdef WITH_ANTIFLOOD
modparam(“pike”, “sampling_time_unit”, 2)
modparam(“pike”, “reqs_density_per_unit”, 16)
modparam(“pike”, “remove_latency”, 4)
htable params
ip ban htable with autoexpire after 5 minutes
modparam(“htable”, “htable”, “ipban=>size=8;autoexpire=300;”)
#!endif
xmlrpc params
#!ifdef WITH_XMLRPC
modparam(“xmlrpc”, “route”, “XMLRPC”);
modparam(“xmlrpc”, “url_match”, “^/RPC”)
#!endif
debugger params
#!ifdef WITH_DEBUG
modparam(“debugger”, “cfgtrace”, 1)
modparam(“debugger”, “log_level_name”, “exec”)
#!endif
nathelper params
#!ifdef WITH_WEBSOCKETS
modparam(“nathelper|registrar”, “received_avp”, “$avp(RECEIVED)”)
Note: leaving NAT pings turned off here as nathelper is only being used for WebSocket connections. NAT pings are not needed as WebSockets have their own keep-alives.
#!endif
Routing Logic
Main SIP request routing logic processing of any incoming SIP request starts with this route
request_route {
# per request initial checks
route(REQINIT);
#!ifdef WITH_WEBSOCKETS
if (nat_uac_test(64)) {
force_rport();
if (is_method("REGISTER")) {
fix_nated_register();
} else {
fix_nated_contact();
if (!add_contact_alias()) {
xlog("L_ERR", "Error aliasing contact <$ct>\n");
sl_send_reply("400", "Bad Request");
exit;
}
}
}
#!endif
# NAT detection
route(NATDETECT);
# CANCEL processing
if (is_method("CANCEL")) {
if (t_check_trans()) {
route(RELAY);
}
exit;
}
# handle requests within SIP dialogs
route(WITHINDLG);
### only initial requests (no To tag)
# handle retransmissions
if(t_precheck_trans()) {
t_check_trans();
exit;
}
t_check_trans();
# authentication
route(AUTH);
# record routing for dialog forming requests (in case they are routed) - remove preloaded route headers
remove_hf("Route");
if (is_method("INVITE|SUBSCRIBE"))
record_route();
# account only INVITEs
if (is_method("INVITE")) {
setflag(FLT_ACC); # do accounting
}
# dispatch requests to foreign domains
route(SIPOUT);
### requests for my local domains
# handle presence related requests
route(PRESENCE);
# handle registrations
route(REGISTRAR);
if ($rU==$null) {
# request with no Username in RURI
sl_send_reply("484","Address Incomplete");
exit;
}
# dispatch destinations to PSTN
route(PSTN);
# user location service
route(LOCATION);
}
Wrapper for relaying requests
enable additional event routes for forwarded requests – serial forking, RTP relaying handling, a.s.o.
route[RELAY] {
if (is_method("INVITE|BYE|SUBSCRIBE|UPDATE")) {
if(!t_is_set("branch_route")) t_on_branch("MANAGE_BRANCH");
}
if (is_method("INVITE|SUBSCRIBE|UPDATE")) {
if(!t_is_set("onreply_route")) t_on_reply("MANAGE_REPLY");
}
if (is_method("INVITE")) {
if(!t_is_set("failure_route")) t_on_failure("MANAGE_FAILURE");
}
if (!t_relay()) {
sl_reply_error();
}
exit;
}
Per SIP request initial checks
route[REQINIT] {
#!ifdef WITH_ANTIFLOOD
# flood detection from same IP and traffic ban for a while
# be sure you exclude checking trusted peers, such as pstn gateways - local host excluded (e.g., loop to self)
if(src_ip!=myself) {
if($sht(ipban=>$si)!=$null) {
# ip is already blocked
xdbg("request from blocked IP - $rm from $fu (IP:$si:$sp)\n");
exit;
}
if (!pike_check_req()) {
xlog("L_ALERT","ALERT: pike blocking $rm from $fu (IP:$si:$sp)\n");
$sht(ipban=>$si) = 1;
exit;
}
}
if($ua =~ "friendly-scanner") {
sl_send_reply("200", "OK");
exit;
}
#!endif
if (!mf_process_maxfwd_header("10")) {
sl_send_reply("483","Too Many Hops");
exit;
}
if(is_method("OPTIONS") && uri==myself && $rU==$null) {
sl_send_reply("200","Keepalive");
exit;
}
if(!sanity_check("1511", "7")) {
xlog("Malformed SIP message from $si:$sp\n");
exit;
}
}
Handle requests within SIP dialogs
route[WITHINDLG] {
if (!has_totag()) return;
if (has_totag()) {
#sequential request withing a dialog should take the path determined by record-routing
if (loose_route()) {
#!ifdef WITH_WEBSOCKETS
if ($du == "") {
if (!handle_ruri_alias()) {
xlog("L_ERR", "Bad alias <$ru>\n");
sl_send_reply("400", "Bad Request");
exit;
}
}
#!endif
}
exit;
}
#sequential request within a dialog should take the path determined by record-routing
if (loose_route()) {
route(DLGURI);
if (is_method("BYE")) {
setflag(FLT_ACC); # do accounting ...
setflag(FLT_ACCFAILED); # ... even if the transaction fails
}
else if ( is_method("ACK") ) {
# ACK is forwarded statelessy
route(NATMANAGE);
}
else if ( is_method("NOTIFY") ) {
# Add Record-Route for in-dialog NOTIFY as per RFC 6665.
record_route();
}
route(RELAY);
exit;
}
if (is_method("SUBSCRIBE") && uri == myself) {
# in-dialog subscribe requests
route(PRESENCE);
exit;
}
if ( is_method("ACK") ) {
if ( t_check_trans() ) {
# no loose-route, but stateful ACK;
# must be an ACK after a 487
# or e.g. 404 from upstream server
route(RELAY);
exit;
} else {
# ACK without matching transaction ... ignore and discard
exit;
}
}
sl_send_reply("404","Not here");
exit;
}
Handle SIP registrations
route[REGISTRAR] {
if (!is_method("REGISTER")) return;
if(isflagset(FLT_NATS)) {
setbflag(FLB_NATB);
#!ifdef WITH_NATSIPPING do SIP NAT pinging
setbflag(FLB_NATSIPPING);
#!endif
}
if (!save("location"))
sl_reply_error();
exit;
}
User location service
route[LOCATION] {
#!ifdef WITH_SPEEDDIAL
# search for short dialing - 2-digit extension
if($rU=~"^[0-9][0-9]$")
if(sd_lookup("speed_dial"))
route(SIPOUT);
#!endif
#!ifdef WITH_ALIASDB
# search in DB-based aliases
if(alias_db_lookup("dbaliases"))
route(SIPOUT);
#!endif
$avp(oexten) = $rU;
if (!lookup("location")) {
$var(rc) = $rc;
route(TOVOICEMAIL);
t_newtran();
switch ($var(rc)) {
case -1:
case -3:
send_reply("404", "Not Found");
exit;
case -2:
send_reply("405", "Method Not Allowed");
exit;
}
}
# when routing via usrloc, log the missed calls also
if (is_method("INVITE")) {
setflag(FLT_ACCMISSED);
}
route(RELAY);
exit;
}
Presence server processing
route[PRESENCE] {
if(!is_method("PUBLISH|SUBSCRIBE"))
return;
if(is_method("SUBSCRIBE") && $hdr(Event)=="message-summary") {
route(TOVOICEMAIL);
# returns here if no voicemail server is configured
sl_send_reply("404", "No voicemail service");
exit;
}
#!ifdef WITH_PRESENCE
if (!t_newtran()) {
sl_reply_error();
exit;
}
if(is_method("PUBLISH")) {
handle_publish();
t_release();
} else if(is_method("SUBSCRIBE")) {
handle_subscribe();
t_release();
}
exit;
#!endif
# if presence enabled, this part will not be executed
if (is_method("PUBLISH") || $rU==$null) {
sl_send_reply("404", "Not here");
exit;
}
return;
}
IP authorization and user authentication
route[AUTH] {
#!ifdef WITH_AUTH
#!ifdef WITH_IPAUTH
if((!is_method("REGISTER")) && allow_source_address()) {
# source IP allowed
return;
}
#!endif
if (is_method("REGISTER") || from_uri==myself)
{
# authenticate requests
if (!auth_check("$fd", "subscriber", "1")) {
auth_challenge("$fd", "0");
exit;
}
# user authenticated - remove auth header
if(!is_method("REGISTER|PUBLISH"))
consume_credentials();
}
# if caller is not local subscriber, then check if it calls
# a local destination, otherwise deny, not an open relay here
if (from_uri!=myself && uri!=myself) {
sl_send_reply("403","Not relaying");
exit;
}
#!endif
return;
}
Caller NAT detection
route[NATDETECT] {
#!ifdef WITH_NAT
force_rport();
if (nat_uac_test("19")) {
if (is_method("REGISTER")) {
fix_nated_register();
} else {
if(is_first_hop())
set_contact_alias();
}
setflag(FLT_NATS);
}
#!endif
return;
}
RTPProxy control and signaling updates for NAT traversal
route[NATMANAGE] {
#!ifdef WITH_NAT
if (is_request()) {
if(has_totag()) {
if(check_route_param("nat=yes")) {
setbflag(FLB_NATB);
}
}
}
if (!(isflagset(FLT_NATS) || isbflagset(FLB_NATB)))
return;
rtpproxy_manage("co");
if (is_request()) {
if (!has_totag()) {
if(t_is_branch_route()) {
add_rr_param(";nat=yes");
}
}
}
if (is_reply()) {
if(isbflagset(FLB_NATB)) {
if(is_first_hop())
set_contact_alias();
}
}
#!endif
return;
}
URI update for dialog requests
route[DLGURI] {
#!ifdef WITH_NAT
if(!isdsturiset()) {
handle_ruri_alias();
}
#!endif
return;
}
Routing to foreign domains
route[SIPOUT] {
if (uri==myself) return;
append_hf("P-hint: outbound\r\n");
route(RELAY);
exit;
}
PSTN GW routing
route[PSTN] {
#!ifdef WITH_PSTN
# check if PSTN GW IP is defined
if (strempty($sel(cfg_get.pstn.gw_ip))) {
xlog("SCRIPT: PSTN routing enabled but pstn.gw_ip not defined\n");
return;
}
# route to PSTN dialed numbers starting with '+' or '00'
# (international format)
# - update the condition to match your dialing rules for PSTN routing
if(!($rU=~"^(\+|00)[1-9][0-9]{3,20}$"))
return;
# only local users allowed to call
if(from_uri!=myself) {
sl_send_reply("403", "Not Allowed");
exit;
}
if (strempty($sel(cfg_get.pstn.gw_port))) {
$ru = "sip:" + $rU + "@" + $sel(cfg_get.pstn.gw_ip);
} else {
$ru = "sip:" + $rU + "@" + $sel(cfg_get.pstn.gw_ip) + ":"
+ $sel(cfg_get.pstn.gw_port);
}
route(RELAY);
exit;
#!endif
return;
}
XMLRPC routing
#!ifdef WITH_XMLRPC
route[XMLRPC] {
# allow XMLRPC from localhost
if ((method=="POST" || method=="GET")
&& (src_ip==127.0.0.1)) {
# close connection only for xmlrpclib user agents (there is a bug in
# xmlrpclib: it waits for EOF before interpreting the response).
if ($hdr(User-Agent) =~ "xmlrpclib")
set_reply_close();
set_reply_no_connect();
dispatch_rpc();
exit;
}
send_reply("403", "Forbidden");
exit;
}
#!endif
Routing to voicemail server
route[TOVOICEMAIL] {
#!ifdef WITH_VOICEMAIL
if(!is_method("INVITE|SUBSCRIBE"))
return;
# check if VoiceMail server IP is defined
if (strempty($sel(cfg_get.voicemail.srv_ip))) {
xlog("SCRIPT: VoiceMail routing enabled but IP not defined\n");
return;
}
if(is_method("INVITE")) {
if($avp(oexten)==$null)
return;
$ru = "sip:" + $avp(oexten) + "@" + $sel(cfg_get.voicemail.srv_ip)
+ ":" + $sel(cfg_get.voicemail.srv_port);
} else {
if($rU==$null)
return;
$ru = "sip:" + $rU + "@" + $sel(cfg_get.voicemail.srv_ip)
+ ":" + $sel(cfg_get.voicemail.srv_port);
}
route(RELAY);
exit;
#!endif
return;
}
Manage outgoing branches
branch_route[MANAGE_BRANCH] {
xdbg("new branch [$T_branch_idx] to $ru\n");
route(NATMANAGE);
}
Manage incoming replies
onreply_route[MANAGE_REPLY] {
xdbg("incoming reply\n");
if(status=~"[12][0-9][0-9]")
route(NATMANAGE);
}
Manage failure routing cases
failure_route[MANAGE_FAILURE] {
route(NATMANAGE);
if (t_is_canceled()) {
exit;
}
#!ifdef WITH_BLOCK3XX
# block call redirect based on 3xx replies.
if (t_check_status("3[0-9][0-9]")) {
t_reply("404","Not found");
exit;
}
#!endif
#!ifdef WITH_VOICEMAIL
# serial forking
# - route to voicemail on busy or no answer (timeout)
if (t_check_status("486|408")) {
$du = $null;
route(TOVOICEMAIL);
exit;
}
#!endif
}
Supports pseudo-variables to access and manage parts of the SIP messages and attributes specific to users and server. Transformations to modify existing pseudo-variables, accessing only the wanted parts of the information.
Already has over 1000 parameters, variables and functions exported to config file. Supports runtime update framework – to avoid restarting the SIP server when needing to change the config parameters
kamctl
Manage kamailio from command line, providing lots of operations, such as adding/removing/updating SIP users, controlling the ACL for users, managing the records for LCR or load balancing, viewing registered users and internal statistics, etc.
When needed to interact with Kamailio, it does it via FIFO file created by mi_fifo module.
kamdbctl
Helps to configure and database needed by kamailio . First we need to select a database engine in the kamctlrc file by DBENGINE parameter .
Valid values are: MYSQL, PGSQL, ORACLE, DB_BERKELEY, DBTEXT.
The tool can be used to create and manage the database structure needed by Kamailio, therefore it should be immediately after Kamailio installation, in case you plan to run Kamailio with a database backend.
kamcmd
send RPC commands to Kamailio from command line , requires ctl module
siremis
web management interface for Kamailio, written in PHP , AJAX , web 2.0 using MVC architecture
-
-
subscriber, database aliases and speed dial management
-
location table view
-
dispatcher (load balancer), prefix-domain translation and least cost routing (lcr) management
-
access control lists (user groups) and permissions management
-
accounting records and missed calls vies
-
manage call data records (generated from acc records)
-
hash table, dial plan table and user preferences table management
-
offline message storage, presence service and sip trace views
-
communication with Kamailio SIP Server via XMLRPC , JSONRPC
-
communication with FreeSWITCH via event socket
-
create and display charts from statistic data stored by Kamailio
-
user location statistics charts
-
SIP traffic load charts
-
memory usage charts
-
accounting records charts and summary table
-
SQL-based CDR generation and rating billing engine
kamcli
cmd line client written Python
Modules
Registrar
SIP registration processing logic can be defined here .
Path support – off , lazy , strict
Things covered in this article
- Internal architecture
- Configuration language
- least cost routing
- load balancing
- traffic dispatching
- DID routing
- prefix based routing
- SIP trunks and peering
- traffic shaping
- topology hiding
- flood detection
- scanning attacks prevention
- anti-fraud policies
SQL and noSQL connectors
enum and DNS based routing
authentication and authorization
secure communication (TLS)
registration and location services
accounting and call data records
call control – redirect, forward, baring
redundancy and scalability
high availability and failover
websockets and webrtc
References :
Henning Westerholt – Kamailio project-1&1 Internet AG ( 2009 )
The data transmitted by the tag may provide identification or location information, or specifics about the product tagged, such as price, color, date of purchase, etc.
Sensors such as seismic sensors may be read using RFID transceivers, greatly simplifying remote data collection.
