Programming with libpcap
libpcap is a good library to capture network traffic, It's fun to programing with libpcap you could do some experiment or deal with lower layer of OSI model. I'm go back to programing with libpcap in the challenge of capture TCP traffic.
Install development environment
I'm using Fedora 29 and have no idea about your Operating System then some might not work.
$ sudo dnf install gcc make cmake libpcap-devel
libpcap-devel is required, of course.
Write first program to listing all device
It's some kind of Hello World! with libpcap.
#include <stdio.h>
#include <pcap.h>
int main()
{
pcap_if_t *alldevs;
pcap_if_t *d;
int i = 0;
char errbuf[PCAP_ERRBUF_SIZE];
/* Retrieve the device list from the local machine */
if (pcap_findalldevs(&alldevs, errbuf) == -1)
{
fprintf(stderr, "Error in pcap_findalldevs: %s\n", errbuf);
return 0;
}
/* Print the list */
for (d = alldevs; d != NULL; d = d->next)
{
printf("%d. %s", ++i, d->name);
if (d->description)
printf(" (%s)\n", d->description);
else
printf(" (No description available)\n");
}
if (i == 0)
{
printf("\nNo interfaces found! Make sure libPcap is installed.\n");
return 1;
}
/* Free device list */
pcap_freealldevs(alldevs);
}
Compile and run
It's the same to complie Hello World! but you need to add -lpcap to link libpcap to your program.
gcc ./src/list_devices.c -o ./list_devices -lpcap && ./list_devices
Result:
1. enp3s0 (No description available)
2. lo (No description available)
3. any (Pseudo-device that captures on all interfaces)
4. virbr0 (No description available)
5. bluetooth-monitor (Bluetooth Linux Monitor)
6. nflog (Linux netfilter log (NFLOG) interface)
7. nfqueue (Linux netfilter queue (NFQUEUE) interface)
8. bluetooth0 (Bluetooth adapter number 0)
9. usbmon0 (All USB buses)
10. wlo1 (No description available)
11. usbmon1 (USB bus number 1)
12. usbmon2 (USB bus number 2)
13. virbr0-nic (No description available)
Credits
Thanks to these guys,