[Winpcap-users] pcap_findalldevs Hangs when calledinWindowsservice

Thomas O'Hare Tom at RedTile.Com
Mon Aug 14 16:20:08 GMT 2006


Richard

If that is the case then my 2 cents says it's a security issue.  XP has,
IMO, much worse security setup then server OS's.

But that all makes sense, XP & security.

Thanks,
~ Thomas O'Hare ~
President, RedTile, Inc. - DBA: RedTile Software
Web, Wireless, Network, Database & Systems Software
+1.407.295.9148 ; +49.8651.717950 ; http://www.RedTile.Com/
Operations Manager; Virtual FoxPro User Group
Tom at VFUG.Org ; http://www.VFUG.Org/


Richard Bellengere wrote:
> Hi.
>  
> It seems to be either an XP thing or particular to my machine. I got it
> running on a Server2000 machine - First Time!
> I will try some other machines here in the office if I can get my hands
> on them.
>  
> Regards
> RichardB
> 
> ________________________________
> 
> From: winpcap-users-bounces at winpcap.org
> [mailto:winpcap-users-bounces at winpcap.org] On Behalf Of Gianluca Varenni
> Sent: 11 August 2006 18:00
> To: winpcap-users at winpcap.org
> Subject: Re: [Winpcap-users] pcap_findalldevs Hangs when
> calledinWindowsservice
> 
> 
>  
> 
> 	----- Original Message ----- 
> 	From: Richard Bellengere <mailto:RichardB at thoroughtec.com>  
> 	To: winpcap-users at winpcap.org 
> 	Sent: Friday, August 11, 2006 5:36 AM
> 	Subject: RE: [Winpcap-users] pcap_findalldevs Hangs when
> calledinWindowsservice
> 
> 	Hi.
> 	 
> 	Checked Visual Studio 2005 Express and WinPCap version 4.0.
> 	Checked Visual Studio 2003 C++  and WinPCap version 4.0.
> 	Checked program compiled as Multibyte Characters and Unicode
> Characters.
> 	 
> 
> This doesn't influence WinPcap.
> 
> 	 
> 	Checked program compiled linked to runtime libraries in
> multithreaded dll and static inclusion of multithreaded runtime
> libraries.
> 	I tried compiling the same code in to a windowed app (instead of
> console app) and running that as a service.  
> 	 
> 	All result in the same problem. pcap_findalldevs hangs.
> 	 
> 	The documetation makes reference to pcap_findalldevs_ex, but I
> have not been able to find it in headers and compile, Am I missing
> something?
> 	 
> 
> If you want to use pcap_findalldevs_ex, just include pcap.h (do *NOT*
> include any other header), and have both WPCAP and HAVE_REMOTE defined
> as preprocessor directives. In any case pcap_findalldevs_ex is a wrapper
> against pcap_findalldevs, which in turn calls PacketGetAdapterNames,
> which is almost certainly the API that hangs. So it does not help.
> 
> 	 
> 	Is it time to start loading the debug version of the packet.dll
> to get more information?
> 	 
> 
> That would be very helpful. Please use WinPcap 4.0alpha1, as this
> version produces a much more verbose trace.
>  
> Have a nice day
> GV
> 
> 	 
> 	Regards
> 	RichardB
> 
> ________________________________
> 
> 	From: winpcap-users-bounces at winpcap.org
> [mailto:winpcap-users-bounces at winpcap.org] On Behalf Of Gianluca Varenni
> 	Sent: 10 August 2006 18:15
> 	To: winpcap-users at winpcap.org
> 	Subject: Re: [Winpcap-users] pcap_findalldevs Hangs when
> calledinWindowsservice
> 	
> 	
> 	Richard,
> 	 
> 	I'll try to create a small test application to reproduce the
> problem. One thing came to my mind: have you changed the compilation
> properties of your application so have it thread safe?
> 	 
> 	Under VC2003, it's in the project properties, under C/C++ ->
> Code generation -> Runtime Library. Be sure to set it to set it to
> multithreaded (or multithreaded DLL, depending on the flavor of CRT that
> you want to use).
> 	 
> 	have a nice day
> 	GV
> 	 
> 	 
> 	 
> 
> 		----- Original Message ----- 
> 		From: Richard Bellengere
> <mailto:RichardB at thoroughtec.com>  
> 		To: winpcap-users at winpcap.org 
> 		Sent: Thursday, August 10, 2006 1:06 AM
> 		Subject: RE: [Winpcap-users] pcap_findalldevs Hangs when
> called inWindowsservice
> 
> 		Hi
> 		 
> 		Sorry - my sample app depends on way too much for me to
> quickly zip it up and post it.
> 		 
> 		I'm using 3.1. I will try 4.0 and let you know what
> happens.
> 		I'm using Visual C++ 2005 Express. I will try Visual
> Studio 2003 for size too.
> 		 
> 		Some more information that may be of interest.  
> 		My service is compiled as a console application. When
> running it (in debug mode) as a console app and not a service,
> pcap_findalldevs is successful only if run from the main thread.
> pcap_loop can be run from the new thread no problem.  When I do the same
> thing in a windowed application I can call pcap_findalldevs from the new
> thread without issue.  
> 		 
> 		It really smacks of a thread permissions issue. I've
> tried making sure the apps and services are running as admin (because of
> npf and nm), but that does not seem to help. Right now I'm trying to
> find out what the difference is between a console thread and a Window
> thread.
> 		 
> 		Regards
> 		RichardB
> 
> ________________________________
> 
> 		From: winpcap-users-bounces at winpcap.org
> [mailto:winpcap-users-bounces at winpcap.org] On Behalf Of Gianluca Varenni
> 		Sent: 09 August 2006 19:15
> 		To: winpcap-users at winpcap.org
> 		Subject: Re: [Winpcap-users] pcap_findalldevs Hangs when
> called in Windowsservice
> 		
> 		
> 		Richard,
> 		 
> 		can you please provide a sample app showing the problem?
> 		 
> 		Which version of WinPcap are you using? WinPcap 3.1 has
> a known bug that affects services based on WinPcap, bug that has been
> fixed in the newer versions of WinPcap like 4.0alpha1.
> 		 
> 		Have a nice day
> 		GV
> 
> 			----- Original Message ----- 
> 			From: Richard Bellengere
> <mailto:RichardB at thoroughtec.com>  
> 			To: winpcap-users at winpcap.org 
> 			Sent: Tuesday, August 08, 2006 5:44 AM
> 			Subject: [Winpcap-users] pcap_findalldevs Hangs
> when called in Windows service
> 
> 			Hi.
> 			 
> 			I'm getting exactly the same thing.  Did you
> ever get a solution to this problem?
> 			 
> 			It seems to have something to do with
> findalldevs being called from a new thread and not the process's main
> thread.
> 			 
> 			Thanks
> 			RichardB
> 
> 			
> ________________________________
> 
> 
> 			
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