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.

The proxy can be used in connection with Net::SIP::Registrar to work as a registrar too. In this case incoming packets from the dispatcher need to be forwarded to the registrar and only if the registrar does not handle the packet (method receive in Net::SIP::Registrar returns () ) it should be handled by the proxy.

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, 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.

registrar

This is either a hash reference which can be used in the constructor of Net::SIP::Registrar or a registrar object itself (only criteria is that it needs to have a method receive with the behavior described for Net::SIP::Registrar).

If given all incoming REGISTER requests will be forwarded to the registrar (by calling it's method receive) and only if the registrar does not handle the packet (method returns ()) it will be handled by the proxy.

rewrite_contact

Callback which is used in rewriting Contact headers. If one puts user@host in it should rewrite it and if one puts something without '@' it should try to rewrite it back (and return () if it cannot rewrite it back). A working default implementation is provided.

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.

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