How to use pcap_stats in libpcap ?

Question

Hello !

I added the following function to the sniffex code (http://www.tcpdump.org/sniffex.c):

typedef struct pcap_stat mystat;

mystat *mystatp;

/* Put the interface in statstics mode */
if(pcap_stats(handle, mystatp) < 0)
{
    fprintf(stderr,"\nError setting the mode.\n");
    pcap_close(handle);
    /* Free the device list */
    return;
}

Sniffex code is working fine for me - but as soon as I add this code, I am getting a segmentation fault error :(

Can anyone please help me out ?

Thanks a ton.

Answer 1

I believe you forgot to allocate memory for mystat.

Try this:

typedef struct pcap_stat mystat;

...

mystat actualStat; /* allocate memory for mystat on stack - you can also do it on the heap by malloc-ing */
mystat *mystatp = &actualStat; /* use allocated memory */

/* Put the interface in statistics mode */
if(pcap_stats(handle, mystatp) < 0)
{
    fprintf(stderr,"\nError setting the mode.\n");
    pcap_close(handle);
    /* Free the device list */
    return;
}

In Pcap.Net I use pcap_stats_ex() but it's probably only available on WinPcap and not on libpcap.