NAME

       Net::SIP::Leg - Wrapper around Socket for sending and receiving SIP packets

SYNOPSIS

         my $leg = Net::SIP::Leg->new( addr => '192.168.0.2' );
         $leg->deliver( $packet, '192.168.0.5:5060' );

DESCRIPTION

       A Leg wraps the socket which is used to send and receive packets.  It provides ways to
       strip Via header from incoming packets, to add Via header to outgoing packets and to add
       Record-Route header while forwarding.

       It's usually not used directly, but from Net::SIP::Dispatcher.

CONSTRUCTOR

       new ( %ARGS )
           The constructor creates a new object based on the hash %ARGS.  The following keys are
           used from %ARGS:

           sock    The socket as IO::Socket object. "addr", "port", "family" and "proto" will be
                   determined from this object and not from %ARGS.  This will be used to create
                   the SocketPool object.

           socketpool
                   The socketpool as Net::SIP::SocketPool compatible object. This argument can
                   not be used together with "sock". It will instead determine the master socket
                   by calling master on the given SocketPool object.

           addr    The local IP address of the socket. If this is given but no port it will
                   extract port from addr, if it's in the format "host:port".

           host    The hostname matching "addr". This is used to create default contact
                   information and the Via header. If not given defaults to the IP address.  Use
                   of hostname instead of IP address is relevant for TLS where the name is needed
                   in validation of the peers certificate.

           port    The port of the socket. Defaults to 5060.

           family  The family of the socket. Will be determined from "addr" if omitted.

           proto   The connection protocol, e.g. 'udp', 'tcp' or 'tls'. Defaults to 'udp'.

           dst     The optional fixed target of the leg as hash with keys "host", "addr", "port"
                   and "family".

           contact Optional contact information which will be added as Record-route header to
                   outgoing requests and used within Contact header for 200 Responses to INVITE.
                   If not given it will be created based on "addr", "port" and "proto".

           tls     Optional arguments to be used in creating a TLS connection, as expected by
                   IO::Socket::SSL.  These are used for both incoming and outgoing TLS
                   connection. Typically this involves "SSL_cert_file", "SSL_key_file" and
                   "SSL_ca_file" or similar.

           If no socket is given with "sock" it will be created based on "addr", "port" and
           "proto". If this fails the constructur will "die()".

           The constructor will create a uniq branch tag for this leg.

METHODS

       forward_incoming ( PACKET )
           Modifies the Net::SIP::Packet PACKET in-place for forwarding, e.g strips top Via
           header in responses, adds received parameter to top Via header in requests, handles
           the difference between forwarding of requests to strict or loose routes and inserts
           Record-Route header in requests.

       forward_outgoing ( PACKET, LEG_IN )
           Similar to forward_incoming, but will be called on the outgoing leg. LEG_IN is the
           Net::SIP::Leg, where the packet came in (and where forward_incoming was called). Will
           add Record-Route header and remove itself from Route.

       deliver ( PACKET, ADDR, [ CALLBACK ] )
           Delivers Net::SIP::Packet PACKET through the leg $self to ADDR.  ADDR is a hash with
           the keys "host", "addr", "port" and "family".  Usually this method will be call from
           within Net::SIP::Dispatcher.

           If the packet was received by the other end (which is only possible to say if a
           reliable protocol, e.g. 'tcp' was used) it will call CALLBACK if provided. See
           invoke_callback in Net::SIP::Util for the format of callbacks. If the packet could not
           be delivered CALLBACK will be invoked with the appropriate errno ($!).

           While delivering requests it adds a Via header.

       receive(PACKET, FROM)
           This is called from the dispatcher if the the Net::SIP::Packet PACKET was received
           from FROM. FROM is given as hash with keys "addr", "port", "family" and "proto".  This
           function might process the packet further or block it.

           It will return "(PACKET, FROM)" in the normal case or "()" if blocked.

       check_via ( PACKET )
           Returns TRUE if the top Via header in the Net::SIP::Packet PACKET contains the
           branch-tag from $self, otherwise FALSE. Used to check if the response came in through
           the same leg the response was send.

       add_via ( PACKET )
           Adds itself to PACKET as Via header.

       can_deliver_to ( ADDR|%SPEC )
           Returns TRUE if the leg can deliver address specified by ADDR or %SPEC.  ADDR is a
           full or partial SIP URI.

           If the caller has 'proto','addr','port' and 'family' already as separate items it can
           call the method with %SPEC instead.

           Right now it has now way to check if the leg can deliver to a specific host because it
           has no access to the routing information of the underlying OS, so that only proto will
           be checked.

       match(%SPEC)
           This checks if the given SPEC matches the leg. This is used from inside the get_legs
           in Net::SIP::Dispatcher to get all legs matching specific criteria. The SPEC can
           contain the keys "addr", "port" and "proto" which match the arguments given during
           construction of the leg or are obtained from the legs socket.  Additionally "sub" can
           be used to specify a function which gets called with the leg object and must return
           true on match only.

           The method returns true if there was a full match and false otherwise.

       socketpool
           This returns the Net::SIP::SocketPool object associated with the leg.

       laddr(LEVEL)
           This will return the local address of the socket, either as address only (LEVEL is 0)
           or as "ip:port" (higher levels).

       dump
           Returns string containing information about the leg.  Used for debugging.