NAME

       Net::SIP::StatelessProxy - Simple implementation of a stateless proxy

SYNOPSIS

       ..

DESCRIPTION

       This package implements a simple stateless SIP proxy.  Basic idea is that the proxy has either a single
       or two legs and that the packets are exchanged between those legs, e.g. packets incoming on one leg will
       be forwarded through the other leg.

       Because this is a stateless proxy no retransmits will be done by the proxy.

       If the proxy should work as a registrar too it should be put after a Net::SIP::Registrar in a
       Net::SIP::ReceiveChain.

       While forwarding the proxy will be insert itself into the packet, e.g. it will add Via and Record-Route
       header while forwarding requests.

       Additionally it will rewrite the Contact header while forwarding packets (see below), e.g. if the Contact
       header points to some client it will rewrite it, so that it points to the proxy and if it already points
       to the proxy it will rewrite it back so that it again points to the client.

CONSTRUCTOR

       new ( %ARGS )
           Creates a new stateless proxy. With %ARGS the behavior can be influenced:

           dispatcher
                   The Net::SIP::Dispatcher object managing the proxy.

           rewrite_contact
                   Callback which is used in rewriting Contact headers.  If one puts user@host in it or if it is
                   called  with force_rewrite then it should rewrite it and if one puts something without '@' it
                   should try to rewrite it back or return () if it cannot be rewritten back.

                   A working default implementation is provided.   If  you  want  to  implement  your  own:  the
                   callbacks  gets  the arguments contact, incoming_leg and outgoing_leg and force_rewrite.  For
                   rewriting a contact of user@host the legs will be Net::SIP::Leg objects.  For  rewriting  the
                   contact  back  outgoing_leg  can  be  either  a  leg object and you should check if it is the
                   expected leg. Or it is a scalar reference which you should fill with the leg  extracted  from
                   the  contact.   The function should return the new contact or nothing if there was nothing to
                   rewrite or the rewrite failed.

                   Note that some servers apply length limitations to the contact so  the  function  should  not
                   return too long values.

           rewrite_crypt
                   If  you  want  to  have  your  own  encryption for the rewritten contact you should defined a
                   subroutine here, which gets "data" as the first and "dir" as the second parameter and  should
                   return  the  de/encrypted data. If "dir" is +1 it should encrypt and on -1 it should decrypt.
                   The optional third argument "add2mac" should be included in calculation and  verification  of
                   the  MAC.   The  function  should  return the encrypted/decrypted data or undef if decryption
                   failed because the MAC did not match.

                   If not defined, then RC4 will be used with a (pseudo)random key, 4 byte  (pseudo)random  seed
                   and 4 byte MAC (md5) over seed and data.

           nathelper
                   Optional  Net::SIP::NATHelper::*  object.  When  given it will be used to do NAT, e.g. if the
                   incoming and outgoing legs are different it will rewrite the SDP bodies to use local  sockets
                   and the nathelper will transfer the RTP data between the local and the original sockets.

           force_rewrite
                   Usually  the  contact  header  will  only  be rewritten, if the incoming and outgoing leg are
                   different. With this option one can force the rewrite, even if they are the same.

METHODS

       receive ( PACKET, LEG, FROM )
           PACKET is the incoming packet, LEG is the Net::SIP::Leg where the packet  arrived  and  FROM  is  the
           "ip:port" of the sender.

           Called   from  the  dispatcher  on  incoming  packets.  The  packet  will  be  rewritten  ("Via"  and
           "Record-Route" headers added, Contact modified) and then the packet will be forwarded.

           For requests it can determine the target of the forwarded packet by looking at the  route  or  if  no
           route it looks at the URI. For responses it looks at the next Via header.

       do_nat ( PACKET, INCOMING_LEG, OUTGOING_LEG )
           This  will  be called from receive while forwarding data.  If nathelper is defined it will be used to
           rewrite SDP bodies and update nathelpers internal states to forward RTP data.

           Return values are like forward_outgoing in Net::SIP::Leg, e.g.  it will return "[code,text]" on error
           or "()" on success, where success can be that the packet was rewritten or that there was no  need  to
           touch it.

UNDOCUMENTED METHODS

       idside2hash

perl v5.36.0                                       2023-09-29                      Net::SIP::StatelessProxy(3pm)