[reSIProcate] Proposal for adding STUN client support

["Matthias Moetje - TERASENS GmbH" <moetje@xxxxxxxxxxxx>]

Hi,

 

in my efforts to implement client support for STUN I found

that it is necessary to modify the UDP transport to implement

this functionality (as Dmytrow already mentioned in a previous

post).

I think this functionality might be of interest for others, too,

so here's a proposal for adding stun client support.

 

Why this is necessary: The STUN functions in stun.cxx work

fine for RTP ports but they can't be used directly for the SIP

UDP ports because the stack is already bound to these ports.

Even when binding with SO_REUSEPORT, the response is received

by the stack and not by the stun function (at least on Windows),

so it is necessary to do the STUN communication in the UdpTransport

class itself. This class already implements a stun server, so I

see no reason why the client should be implemented elsewhere.

 

I think the application should have control over the use of the

discovered public IP address and port (a more automatic and

integrated solution could be added later), therefore the application

would need to get a pointer to the UdpTransport class. This could be

done by turning

 

void addTransport( TransportType protocol, int port=0, IpVersion 
version=V4, StunSetting stun=StunDisabled,...);

 

into

 

Transport addTransport( TransportType protocol, int port=0, IpVersion version=V4, StunSetting stun=StunDisabled,...);

 

The StunSetting enumeration could be extended to

 

typedef enum
{
   StunDisabled,
   StunEnabled, //Server only

   StunClient,   //Client only

   StunClientServer //Client and Server
} StunSetting;

 

This would be 100% compatible and require no changes to existing

code nor would it change any existing behaviour.

 

 

UdpTransport would receive two public methods:

 

//returns true if message was sent successfully

bool StunTest(StunAddress4& dest, int testNum);

 

//returns true and discovered address if last StunTest was successful

bool StunResult(StunAddress4* srcAddr);

 

 

Would there be any resons against implementing it

this way? Any suggestions?

 

Best regards,

Matthias Moetje

TERASENS GmbH
Augustenstraße 24
80333 Munich
GERMANY

Phone: Fax: e-mail: Web:

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