Get IP address of interface in Linux using pcap

Question

Is there a way how to get an IP address of an interface in Linux using libpcap?

I have found this, Get IP address of an interface on Linux , but that doesn't use pcap.

Also, in the pcap examples it is said that something like this should get your IP but it gives you your network address.

Answer 1

Using the pcap_findalldevs function:

#include <pcap/pcap.h>
#include <arpa/inet.h>

static char errbuf[PCAP_ERRBUF_SIZE];

int main() {
    pcap_if_t *alldevs;
    int status = pcap_findalldevs(&alldevs, errbuf);
    if(status != 0) {
        printf("%s\n", errbuf);
        return 1;
    }

    for(pcap_if_t *d=alldevs; d!=NULL; d=d->next) {
        printf("%s:", d->name);
        for(pcap_addr_t *a=d->addresses; a!=NULL; a=a->next) {
            if(a->addr->sa_family == AF_INET)
                printf(" %s", inet_ntoa(((struct sockaddr_in*)a->addr)->sin_addr));
        }
        printf("\n");
    }

    pcap_freealldevs(alldevs);
    return 0;
}

Output of sudo ./pcap :

eth0: 192.168.2.1
usbmon1:
usbmon2:
usbmon3:
usbmon4:
usbmon5:
any:
lo: 127.0.0.1