Re: Binding to no particular address/INADDR_ANY?

[Toralf Lund <toralf lund pgs com>]

Frank Rehberger wrote:
>  On 16.09.2010 13:54, Toralf Lund wrote:
>   
> > When setting up a TCP/IP based server ORB, I can specify the IP
> > host-name to bind to *via option -ORBIIOPIPName=..., or use an
> > internal default, which is influenced by the value of -ORBNetId. But
> > it does not seem like I can choose not to bind to an address at all,
> > as in set up the server to listen for connections on ANY interface the
> > machine may have. Why is that? Or is there some way I can do this?
> > I've **-ORBIIOPIPName=0.0.0.0 based on the theory that this would be
> > like specifying INADDR_ANY in a socket address structure, but it
> > didn't seem to work...
> >     
>
> ORBit2 has not been designed for this case. Nonetheless, it would be
> possible to add this INADDR_ANY  feature.
>
> Listening to all interfaces, would require to encode all endpoints into
> each object reference, which could be implemented quite easily, but
> blowing up the IORs extremely. Moreover, using this strategy for
> clients  it becomes unclear which of the encoded endpointsin IOR is
> reachable/routable, which may cause timely connection-trials.
>   
I don't understand what you are talking about here, I'm afraid. Doesn't 
the object reference just need one (any usable) address? Isn't 
everything ultimately about mapping the CORBA stuff into a socket (and 
vice versa), which just works for INADDR_ANY?
> If you need an ORB being able to listen to all NICs attached, I
> recommend The C++ ACE ORB (TAO). TAO is listening to all NICs by default.
>   
Quite. I've thought about switching many times. However, I rather like 
the way ORBit2 transparently integrates into my Glib/Gtk or Qt (via its 
Glib support) applications, i.e. that I can just run the normal mainloop 
and have all the CORBA calls appear without having to think about them. 
With other ORBs I generally have to use extra threads or cumbersome 
timer-based polling, right?
> Beside this, by default ORBit2 is using  Unix-Domain-Sockets, so the
> ORBIIOPIPName option will not have taken effect at all, I assume. To get
> ORBit2 servers  talking with remote hosts, the following command line
> parameters should be set:
>   
I knew that, of course...
> -ORBLocalOnly=0  -ORBIIOPUNIX=0 -ORBIIOPIPv4=1 -ORBIIOPIPName=A.B.C.D 
> -ORBIIOPIPSock=PortNum
>
> Adding the following option will change  to corbaloc IOR string format,
> which eases to figure out effect of command lines parameters.
> -ORBCorbaloc=1
>
> You can use the orbit-name-server-2 to verify:
> /usr/bin/orbit-name-server-2 -ORBCorbaloc=1 -ORBLocalOnly=0 
> -ORBIIOPUNIX=0 -ORBIIOPIPv4=1 -ORBIIOPIPName=A.B.C.D  -ORBIIOPIPSock=PortNum
>
>
> If you try -ORBIIOPIPName=0.0.0.0 and check the object-reference
> printed  to console, you will notice that ORBit2 encodes 0.0.0.0 into
> the stringified object reference, which is invalid and not reachable by
> any client.
>   
I suppose that's the problem... Although I don't use the stringified 
object references - frankly I think the whole concept of those is 
fundamentally flawed when it comes to setting up a proper networked app. 
So I'm relying on "static" corbaloc references. Supporting those is not 
really documented, and requires the use of a semi-private function, but 
actually it all works rather well.

- Toralf


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