NAME

Net::SIP - Framework SIP (Voice Over IP, RFC3261)

SYNOPSIS

...

DESCRIPTION

Net::SIP consists of packages for handling the SIP packets, for transport of the packets, for processing the packets and on top of all that a simplified layer for common tasks.

Addionally Net::SIP::Util provides utility functions and Net::SIP::Debug provides a debugging layer used by all these packages. Especially it provides the function invoke_callback which is used for all callbacks unless documentation specifies otherwise. This function supports a variety of different callback styles.

For first and simple applications you best start with Net::SIP::Simple. If this is no longer enough you might look at the details of Net::SIP::Dispatcher, Net::SIP::Endpoint, Net::SIP::Register and Net::SIP::StatelessProxy. Although these packages are in itself well documented the functionality and the design is best understandable if you look how it gets used in the source of Net::SIP::Simple.

SIP packet handling

Net::SIP::Packet: The base class for handling SIP packets and provides ways to parse, construct and manipulate SIP packets.
Net::SIP::Request: Derived from Net::SIP::Packet and handles the request packets. Provides ways to create special requests like ACK or CANCEL based on previous requests and responses, for creating responses based on requests, for authorization of requests.
Net::SIP::Response: Derived from Net::SIP::Packet and handles the response packets.
Net::SIP::SDP: Handles SDP bodies from SIP packets. Provides ways to parse, construct these bodies, to get media information from them and to manipulate the SDP data for NAT etc.

Transport of SIP packets

Net::SIP::Leg: Encapsulates socket for transport of packet. Provides way to find out, if target is reachable through this socket. Prepares incoming, outgoing and forwarding packets by removing or adding header like Via, Record-Route.
Net::SIP::Dispatcher: Handles new packets coming in through a Net::SIP::Leg. Delivers outgoing packets through the appropriate Net::SIP::Leg. Handles timeouts and retransmission of outgoing packets, lookup of the appropriate leg through DNS etc.
Net::SIP::Dispatcher::Eventloop: Simple implementation of an event loop for handling socket events and timers. Can be replaced to integrate into other event loops, like Tk, Lib::Event or POE.

Processing of SIP packets, application layer

Net::SIP::Endpoint: Implements a SIP endpoint (UAC,UAS). Provides ways to INVITE or BYE calls or to handle incoming calls. Calls themselves will be handled by Net::SIP::Endpoint::Context.
Net::SIP::Registrar: Simple implementation of a registrar.
Net::SIP::StatelessProxy: Simple implementation of a stateless proxy. Stateful proxies should probably be implemented by putting multiple Net::SIP::Endpoints together.
Net::SIP::Blocker: Can block requests by method name with custom error code.
Net::SIP::ReceiveChain: Can contain various objects for processing objects. Useful in connection with Net::SIP::Authorize.
Net::SIP::Redirect: Works together with a registrar and redirects requests.
Net::SIP::Authorize: If put into a Net::SIP::ReceiveChain it requests and checks authorization and gives only authorized requests to the next member of the chain.

Simplified Layer for common tasks

Net::SIP::Simple: Provides simple layer for common tasks and tests, like sending a voice message to somebody, receiving a message or even implementing an answer machine. Together with Net::SIP::Simple::RTP it is possible to handle simple RTP data (PCMU/8000).

Error handling

Unless otherwise documented the common way to propagate errors is to raise an exception, e.g. call die(). This might especially happen when parsing packets from strings, so unless you want to crash your application on bad input you should catch these exceptions with eval.

EXPORTS

By default nothing is exported. There are various arguments for exporting:

:alias: Exports constants as aliases for the Net::SIP::* packages, e.g. 'Simple' for 'Net::SIP::Simple', 'Registrar' for 'Net::SIP::Registrar', 'Packet' for 'Net::SIP::Packet', 'NATHelper_Client' for 'Net::SIP::NATHelper::Client' etc.
:util: Exports everything (tag ':all') from Net::SIP::Util.
:debug: Exports the default exports from Net::SIP::Debug.
:all: Everything from ':debug', ':util' and ':alias'.
rtp=MINPORT-MAXPORT|rtp:MINPORT-MAXPORT: Set the range of ports to be used for creating RTP sockets to MINPORT..MAXPORT. This affects Net::SIP::Util::create_rtp_sockets.
debug=LEVEL|debug:LEVEL: Set Debugging level to LEVEL
string: Strings where the first character is upper case will be interpreted as aliases for Net::SIP::* and it will try to export it. If the first character is lower case it will try to import it from Net::SIP::Util.

EXAMPLES

  use Net::SIP 'invoke_callback'; # use Net::SIP::Util 'invoke_callback'
  use Net::SIP ':debug';          # use Net::SIP::Debug
  use Net::SIP ':util';           # use Net::SIP::Util ':all'

  use Net::SIP ':alias';
  Packet->new( ... );             # Net::SIP::Packet->new( ... )


  # restrict rtp sockets from command line
  perl -MNet::SIP=rtp:4000-4010 program.pl

BUGS

Support for TCP and SIPS and not or not fully implemented.

COPYRIGHT

This module and are modules in the Net::SIP Hierarchy distributed together with this module are copyright (c) 2006-2013, Steffen Ullrich. All Rights Reserved. These modules are free software. They may be used, redistributed and/or modified under the same terms as Perl itself.