Re: [tcpdump-workers] Libpcap recieves partial packets

2012-05-08 Thread Hrju
Libpcap of version 1.0.0 and greater uses mmap with kernel space ring buffer. You may see the following comments in create_ring() function, which creates this ring and populates it with fixed size frames: "* So, for now, we just do this for Ethernet devices, where * there's no met

Re: [tcpdump-workers] Libpcap recieves partial packets

2012-05-08 Thread Gianluca Varenni
I've actually seen a similar problem with different NIC drivers, e.g. on RHEL6 running in ESXi 4 with the vmxnet3 drivers. http://article.gmane.org/gmane.network.tcpdump.devel/5703 GV -Original Message- From: tcpdump-workers-ow...@lists.tcpdump.org [mailto:tcpdump-workers-ow...@lists.t

Re: [tcpdump-workers] Libpcap recieves partial packets

2012-05-08 Thread Hrju Blja
Hi, Both machines are with Intel Gigabit Ethernet adapter, with different revisions, though. Both use e100e driver. So what you are actually saying, that NIC driver may handle it in a wrong way? If so, what are the possible reasons? How exactly you found out the driver ring frames size? Inserting

Re: [tcpdump-workers] Libpcap recieves partial packets

2012-05-08 Thread rixed
Also, We've seen such strange things happen on some card (broadcom) when changing the MTU: the internal ring buffer (the one in the card not the one in libpcap) was not handling dynamic resize properly, and reported batch of strange things. What's your network adapter? - This is the tcpdump-worker

Re: [tcpdump-workers] Libpcap recieves partial packets

2012-05-08 Thread rixed
Maybe your device is actually receiving these jumbos and the driver does not discard them for some reason? - This is the tcpdump-workers list. Visit https://cod.sandelman.ca/ to unsubscribe.

[tcpdump-workers] Libpcap recieves partial packets (pcap_pkthdr.caplen

2012-05-08 Thread Hrju Blja
Hi, I develop a Linux sniffer application , which uses libpcap 1.2.0 library. The problem is that on some 2.6.16 and 2.4 kernel machines, which are pretty much "usual", SOMETIMES SOME packets are captured partially, i.e. tpacket_hdr structure tp_snaplen value is less then tp_len value. I see this r