getifaddrs.c

#include <sys/types.h>
#include <sys/socket.h>
#include <net/if_dl.h>  /* LLADDR */

#include <ifaddrs.h>

#include <err.h>
#include <stdlib.h>
#include <stdio.h>

int
main(int argc, char *argv[])
{
        struct ifaddrs *ifaphead, *ifap;

        if (getifaddrs(&ifaphead) != 0)
                err(1, "getifaddrs()");

        for (ifap = ifaphead; ifap; ifap = ifap->ifa_next) {
                struct sockaddr_dl *sdl =
                        (struct sockaddr_dl *)ifap->ifa_addr;
                if (!sdl || sdl->sdl_family != AF_LINK)
                        continue;

                uint8_t *mac;
                mac = (uint8_t *)LLADDR(sdl);
                printf("Interface: %s MAC: %02x:%02x:%02x:%02x:%02x:%02x\n",
                                ifap->ifa_name,
                                mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
        }

        freeifaddrs(ifaphead);
        exit(0);
}