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 packets. Especially it provides the function
       invoke_callback which is used for all callback unless otherwise in the documentation
       specified. 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 tghe source of Net::SIP::Simple.

   SIP packet handling
       SIP::Net::Packet
           Is the base class for handling SIP packets and provides ways to parse, construct and
           manipulate SIP packets.

       SIP::Net::Request
           Is derived from SIP::Net::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.

       SIP::Net::Response
           Is derived from SIP::Net::Packet and handles the response packets.

       SIP::Net::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 itself 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.