NAME

       Net::SIP::Dispatcher - dispatch SIP packets between legs and endpoint

SYNOPSIS

         my $disp = Net::SIP::Dispatcher->new( ... );
         $disp->deliver( $request );

DESCRIPTION

       This module dispatches Net::SIP::Packets between Net::SIP::Legs and endpoints like
       Net::SIP::Endpoint, Net::SIP::Registrar and Net::SIP::StatelessProxy.

       It manages retransmission of outgoing packets and redelivery of responses to incoming
       requests.

       It is asssociated with an event handling like Net::SIP::Dispatcher::Eventloop.

CONSTRUCTOR

       new ( \@LEGS, EVENTLOOP, %ARGS )
           Creates a new dispatcher object.

           @LEGS is a list of legs or specification for legs. See add_leg for possible formats.

           EVENTLOOP is a eventloop which provides handling of events on file descriptors and
           timers. If not given a new Net::SIP::Dispatcher::Eventloop object will be created and
           used. See there how to define your own event loop package.

           %ARGS are parameters for the behavior of the dispatcher:

           outgoing_proxy
                   Specifies "ip:port" of outgoing proxy, e.g the proxy which will be used for
                   all outgoing packets. A leg to reach this proxy need to exist.

           do_retransmits
                   If TRUE retransmits will be done according to RFC3261. If FALSE no retransmits
                   will be done, which is used in the case of stateless proxies.  Defaults to
                   TRUE.

                   This is the default for the delivery and can be overwritten in sub deliver.

           domain2proxy
                   Optional mapping between target SIP domain and proxy to use.  This is usually
                   a hash of "( domain, "ip_proxy:port_proxy" )" pairs. Special domain '*' can be
                   used to specify a fallback and '*.domain' to include not only the domain but
                   the subdomains too.  See sub deliver for more details.

           dnsresolv
                   Optional function to be used for DNS resolving instead of Net::DNS. This is
                   intended for testing or for interfacing with own resolver code.  The function
                   is called with "(type,name,callback)" and is expected to invoke the callback
                   with the answer. "type" can be SRV, A or AAAA and the answer is expected to be
                   a list consisting of "['SRV',prio,host,port]", "['A',ip,host]" and
                   "['AAAA',ip,host]".

           The constructor will create a timer using the eventloop which will regularly (each
           second) call queue_expire.

METHODS

       set_receiver ( ENDPOINT )
           This sets ENDPOINT as a receiver for incoming packets.  ENDPOINT is an object with a
           method receive or a callback usable by invoke_callback in Net::SIP::Util.

       add_leg ( LEG )
           Adds LEG as a leg to the dispatcher $self. LEG can be either a Net::SIP::Leg object, a
           IO::Handle or a hash reference which is usable in the constructor of Net::SIP::Leg.

           The leg will be added to the dispatchers eventloop for receiving incoming packets.

       remove_leg ( LEG )
           Removes Net::SIP::Leg object LEG from the dispatcher.

       get_legs ( %ARGS )
           Get a list of all Net::SIP::Leg objects matching the criteria given by %ARGS. %ARGS
           can be a combination of:

           addr    Matches if given address matches the legs source address.

           port    Matches if given port matches the legs source port.

           proto   Matches if given proto ('udp','tcp') matches the legs protocol.

           sub     Call given sub with the Net::SIP::Leg as argument. Matches if the sub returns
                   TRUE.

           The leg matches %ARGS if the all conditions specified in %ARGS match.

       add_timer ( WHEN, CALLBACK, [ REPEAT ] )
           Adds a timer using the eventloop.

           WHEN is either an absolute or a relative time (what it is will be decided based on the
           value of WHEN). Absolute times will be specified in time_t (seconds since 1970-01-01
           00:00:00) and relative time will be specified in seconds.  WHEN can be floating point
           to specify subseconds.  WHEN can be 0 to trigger the timer immediately.

           CALLBACK is a callback usable by invoke_callback in Net::SIP::Util.

           REPEAT is the optional repeat interval for the timer.

       deliver ( PACKET, %ARGS )
           Delivers Net::SIP::Packet PACKET.  %ARGS can specify hints for delivery:

           id      ID for packet, used in cancel_delivery. If not given the transaction ID of
                   PACKET given by method tid will be used.

           callid  Call-ID for packet, used in cancel_delivery to cancel all deliveries for a
                   specific call. If not given the Call-Id of PACKET given by method callid will
                   be used.

           callback
                   callback which will be called on definite delivery of packet (only possible
                   for TCP) or on definite failure. Callback will be invoked using
                   invoke_callback from Net::SIP::Util with the additional argument of $!.  See
                   sub deliver in Net::SIP::Leg.

           leg     Specifies outgoing Net::SIP::Leg object. For responses created by the endpoint
                   the outgoing leg is usually known, because it's the same as the incoming leg
                   for the request.

           dst_addr
                   Destination, i.e. where to deliver the packet.  This should be given as a hash
                   with the keys "proto" (udp|tcp|tls), "host", "addr", "port" and "family".
                   This is necessary for responses, for requests it can be found out based on the
                   requests URI.

           do_retransmits
                   Specifies if retransmits should be done according to RFC3261. This is usually
                   the case, except for stateless proxies. Overwrites the global parameter with
                   the same name from the constructor for the delivery of the specific packet.

           Delivery of the packet itself will be handled in multiple steps (in the code done
           mainly by sub __deliver:

           •       If a leg is specified it will be used for delivery. dst_addr needs to be
                   specified in this case too.  This is usually the case for locally generated
                   responses.

           •       Otherwise leg and dst_addr will be retrieved using resolve_uri.  See there.

           If the packets could be retransmitted appropriate setups will be done. Retransmission
           will be done until final failure or until cancel_delivery will be called for the
           packet, which usually means, that the packet was successfully delivered because a
           response to the packet was received.

       resolve_uri ( URI, ADDR, LEGS, CALLBACK, [ ALLOWED_PROTO, ALLOWED_LEGS ] )
           Resolves URI to get the destination address and the outgoing leg.  ADDR and LEGS are
           references to lists which will get filled with the computed values.

           If ALLOWED_PROTO is given it will be interpreted as a \@list of protocols.  Only the
           protocols given in the list will be considered and the it will try them in the order
           from the list, e.g. "('tcp','udp')" means that tcp is tried first and only if there is
           no way to do tcp it will try udp. Default is to first try udp and then tcp.

           If ALLOWED_LEGS is given it will be interpreted as a \@list of Net::SIP::Leg objects
           and only these legs are allowed.

           Because the method can be asynchronous (DNS lookups can be involved) it will call
           CALLBACK once it is done. If no errors occurred CALLBACK will be invoked without
           additional arguments, otherwise with the errno as additional argument.

           Resolving will be done as follows:

           •       If domain2proxy is given it will try to get the dst_addr from this, e.g. the
                   address of the proxy responsable for the domain (if any). From dst_addr it
                   will then get the leg.

           •       If still no dst_addr is known it will use outgoing_proxy as the dst_addr.

           •       If still no dst_addr is known but the SIP domain is an IP address this will be
                   used as dst_addr.

           •       The last effort will be made by looking up the SIP domain using DNS with a
                   partial implementation of RFC3263, e.g. it looks at the DNS SRV records but
                   not at NAPTR records.

           •       For each destination address (e.g. proto,addr,port) the outgoing leg will be
                   computed.  This will be done in sub __find_leg4addr by going through all legs
                   and checking, if the leg could deliver to this address by calling
                   can_deliver_to on the leg (see Net::SIP::Leg).

       cancel_delivery ( TYP?,ID )
           Cancels retransmission of packet with id ID. Called from endpoint if response to
           packet came in, which means that the packet was successfully delivered.

           If TYP given packets can be canceled by something else. TYP can be "callid", in which
           case all deliveries for a specific call will be canceled. It can be "id" which will
           cancel the packet with id ID.  Or it can be "qentry" in which case ID will be
           interpreted as the Net::SIP::Dispatcher::Packet object in the queue and it will cancel
           this packet.

           Will return true if the item was canceled, false if no such item was found in delivery
           queue.

       receive ( PACKET, LEG, FROM )
           Called from the eventloop (e.g was setup as a callback) for incoming packets. The new
           Net::SIP::Packet is PACKET, LEG is the Net::SIP::Leg where the packet came in and FROM
           is "ip:port" of the sender.

       queue_expire ( [ NOW ] )
           Expires retransmission queue, e.g. deletes packet where retransmissions failed
           permanently (and calls appropriate callbacks) and initiates pending retransmissions.
           Called from a timer setup in the constructor.