Stupid question: are you storing the header pointer between different calls to pcap_next_ex? That pointer is valid only until the next call to pcap_next_ex, or to pcap_close.
Have a nice day GV PS. header doesn't need to be initialized before the call to pcap_next_ex. Have a nice day GV ----- Original Message ----- From: "Venkatramani, Bharath" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Wednesday, September 15, 2004 10:10 PM Subject: RE: [WinPcap-users] pcap_next_ex and buffer overflow > Yes. I am not incrementing SessionNum in the first place, so it remains at > 0. PcapSession[0] is also not null. When I was debugging my application > further, I see that header->caplen and header->len blow up (for instance, > caplen becomes 1511663 - something like that - unlike the previous > iterations when it was a 2-3 digit number) immediately after the "green > arrow" points to the line "while((res = > pcap_next_ex(PcapSession[SessionNum], &header, &pkt_data))>= 0)". Would this > info help, or is the blowup happening because the header has nothing in it > in the first place? > > -----Original Message----- > From: Guy Harris [mailto:[EMAIL PROTECTED] > Sent: Wednesday, September 15, 2004 4:03 PM > To: [EMAIL PROTECTED] > Subject: Re: [WinPcap-users] pcap_next_ex and buffer overflow > > > > On Sep 15, 2004, at 10:49 AM, Venkatramani, Bharath wrote: > > > I am using winpcap 3.0 and have been having this problem for some time > > now. > > I am calling my DLL from Labview 7.1 and everytime I run my program in > > debug > > mode, I get an error saying that labview has encountered a reading > > access > > violation at 0x0000005 (something to that extent). Then I get a green > > arrow > > pointing to this statement in my code: > > > > |> while( (res = pcap_next_ex(PcapSession[SessionNum], &header, > > &pkt_data))>= 0) > > { > > ... > > } > > Are you certain that > > 1) SessionNum is nonnegative and is less than the number of elements > > in the PcapSession array > > and, if that's true, > > 2) PcapSession[SessionNum] is non-null? > > If not, then you need to change your code to make sure both of those > are true. > > > > ================================================================== > This is the WinPcap users list. It is archived at > http://www.mail-archive.com/[EMAIL PROTECTED]/ > > To unsubscribe use > mailto: [EMAIL PROTECTED] > ================================================================== > > > ================================================================== > This is the WinPcap users list. It is archived at > http://www.mail-archive.com/[EMAIL PROTECTED]/ > > To unsubscribe use > mailto: [EMAIL PROTECTED] > ================================================================== > ================================================================== This is the WinPcap users list. It is archived at http://www.mail-archive.com/[EMAIL PROTECTED]/ To unsubscribe use mailto: [EMAIL PROTECTED] ==================================================================
