UPnP services...

[David Marcovich]

Hi All,

I had found some stuff about UPnP and NAT.
Source code is available at:

http://sourceforge.net/projects/libnat/

My first aproach is this:

#compile exe

type UpnpController
  control_url 	as string * 15
  service_type	as string * 512 
end type

Declare Function LNat_Upnp_Discover  cdecl Lib "libnat.dll" Alias "LNat_Upnp_Discover" ( upnp as UpnpController ) as long
Declare Function LNat_Upnp_Get_Public_Ip cdecl Lib "libnat.dll" Alias "LNat_Upnp_Get_Public_Ip" ( upnp as UpnpController, IP as asciiz, ip_len as long ) as long
Declare Function LNat_Upnp_Controller_Free  cdecl Lib "libnat.dll" Alias "LNat_Upnp_Controller_Free" ( upnp as UpnpController ) as long

function pbmain()
local ip as asciiz * 15, result as long, ip_len as long
local upnp as UpnpController
ip = "255.255.255.255"
ip_len = Sizeof(ip)

result = LNat_Upnp_Discover(upnp)
if result <> 0 then msgbox "Failed at Router comunication" : exit function

result = LNat_Upnp_Get_Public_Ip (upnp, ip, ip_len)
if result <> 0 then msgbox "Router is not UPnP compatible" : exit function

result = LNat_Upnp_Controller_Free(upnp)
MsgBox ip

end function

But doesn't work.
Any ideas ?

Thanks in advance,
David Marcovich

[Brian Chirgwin]

I haven't executed the code as I have UPnP turned off, but looking I see the following.

local ip as Asciiz * 15 should be local ip as ASciiz * 16 ' Need extra byte for ending chr$(0)

I did not double check the declares. AsciiZ might need to be string.


Most home routers have an option to have UPnP turned off and businesses definately do. At least anyone who is worried about security. You don't want someone (hacker) changing your router to allow complete access into your LAN.

[David Marcovich]

Thanks Brian,

I think you are right.
I need know the external IP of a routered PC in order to allow IP to IP chat.
I don't know how MSN works, but I need some like this...

Any ideas are welcomed.

Thanks in advance,
David de Argentina

[Brian Chirgwin]

Are you writing your own chat program? If not, what chat program are you using?

If your using one of the major chat programs, you can configure your router to allow specific ports through. There are many sites that list the port numbers. google "TCP PORTs appname"

MSN Messenger info can be found here. support.microsoft.com/kb/240063

You may also have to allow the application through any firewalls installed.

[José Roca]

The structure must be declared as

TYPE UpnpController
  control_url     AS ASCIIZ PTR
  service_type    AS ASCIIZ PTR
END TYPE

Original C declaration:

/* UpnpController structure definition */
struct LIBNAT_API UpnpController
{
  char * control_url;
  char * service_type;
};

and the ip_len parameter of the LNat_Upnp_Get_Public_Ip function must be BYVAL.