Dear Mr. Varenni,
Thanks for your reply. I just wanted to clarify a few points you have made. (Note: I am using a multicore machine so the multithread is a natural choice and my processing code is definitely not as optimized as your pcap code, but this is a solo project so I don't need to satisfy anyone else) 1. You mention, that I should pre-allocate and reuse buffer space where to store packets and not allocate new buffer. Do you mean something like: PCAPDATANODE myPacketBuffer[amountOfNeededPackets]; // store in a specific memory location predetermined Is PCAPDATANODE packetNode = new PCAPDATANODE(); not a good way to go? 2. To prevent overloading, I need to pause capture (not extraction) for a some amounts time according to SYSTEM time settings, is there a command that can facilitate that? Or should I simply stop the adapter, release it, and then reacquire when the time comes to capture (also would this automatically flush the buffer)? At the moment, I merely stopped the extraction but as you might have predicted the capture continued and I simply continued processing where I last left it off. Thanks again for you time, - Dennis From: Gianluca Varenni [mailto:[email protected]] Sent: Monday, August 10, 2009 2:50 PM To: [email protected]; [email protected] Subject: Re: [Winpcap-users] How to ensure all packets are captured Moving the processing code in a separate thread may or might not help. If you move the processing on a different thread and use a FIFO/linked list to pass the packets among the threads, you will need to copy the packets in your own allocated buffer. Copying a packet is extremely fast, but it makes sense only if your packet processing code is much more CPU intensive than copying the packet itself. Also, using a different thread makes sense if you run on a multicore machine, where basically you can use both the CPUs. If you go this way, remember to preallocate and reuse the buffers in which you copy the packets, do not allocate a new buffer whenever you receive a packet. Hope this helps GV ----- Original Message ----- From: Denis Kourktchan <mailto:[email protected]> To: [email protected] Sent: Sunday, August 09, 2009 1:05 PM Subject: [Winpcap-users] How to ensure all packets are captured Hi Everybody, I am writing an application that is intercepting packets from a network and after reading a whole lot of posts regarding lost messages I figured the fault is usually in application taking too long to process a batch of packets which causes the overfilled buffer to replace oldest messages. So I decided that the following setup is the best possible way to ensure that my messages are not lost. 1. Put capture (using pcap_next_ex()) into a different thread then the processing. 2. Store packets immediately upon extraction into a custom written linked list, adding to the end and processing from the front (in different threads) ensuring no mutex controls are necessary and no idle time. Now here is the problem for which I need your expert advice, since the pcap_next_ex() returns pointers to data, I still need to extract them (I use for loop) before I can store which still preoccupies the capture thread and slows down extraction process. So is there a better way to extract packets without this delay? I would appreciate any and all advice regarding the optimal solution architecture wise. Regards, - Dennis _____ _______________________________________________ Winpcap-users mailing list [email protected] https://www.winpcap.org/mailman/listinfo/winpcap-users
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