[Winpcap-bugs] WinPCAP 4.1 beta on Vista, localhost

[Torsten Jaekel]

Dear WinPCAP team,
 
I am using WinPCAP, version 4.1 beta in order to capture data on an USB
RNDIS device. It works fine on XP.
On Vista (32 or 64 bit, on a Dual Core PC, I have strange trouble:
 
- if I capture the data (it is a MPEG-2 Transport Stream) and send it as
UDP to another PC (leaving my PC) - all is fine
- if I send it to "localhost" - the TS is corrupt, I have quite a lot of
lost TS packets (discontinuities).
 
I tried to use a FiFo, to increase the buffer sizes when opening the
PCAP device etc. Nothing helps.
 
It seems to me, traffic on localhost interfers with WinPCAP driver. The
same effect if I send the data via a Named Pipe to another
driver/thread.
WinPCAP is error free, if I write the captured data into a file. It
happens only when UDP sockets are used with destination on the same PC.
If I stream and record into a file what I have streamed - I see the
corrupted data.
 
My assumption, sockets to localhost on Vista could be too slow, does not
seem to be true. I see that WinPCAP is still using timeouts in case
nothing was captured and the CPU load is not remarkable high.
My software seems to be correct, just changing from file write to UDP
send with the same parameter creates this trouble.
 
Could there be a side effect, streaming to localhost? (but only on
Vista, on XP it works)?
 
Sincerely yours
 
Torsten Jaekel
 

_______________________________________ 



Torsten Jaekel

Broadcom Corporation
Call: +49 30 30 649 396
Direct: +1 949 926 8016
Cell: +49 174 94 33 716
Email: tjaekel at broadcom.com 

 
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