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#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <netdb.h>
#include <ifaddrs.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <assert.h>
#include <string.h>
#include <stdlib.h>
/* example program that uses getifaddrs(3) to get interfaces,
getnameinfo to get IP address and ioctl to get MAC address. */
/* gets the MAC addr for the interface */
int get_if_mac(char *eth, char *mac) {
struct ifreq ifr;
int fd = socket(AF_INET, SOCK_DGRAM, 0);
if (fd == -1) return -1;
strncpy(ifr.ifr_name, eth, sizeof(ifr.ifr_name));
if (ioctl(fd, SIOCGIFHWADDR, &ifr) == -1) return -1;
memcpy(mac, ifr.ifr_hwaddr.sa_data, IFHWADDRLEN);
return 0;
}
/* get all interfaces, their IPv4/v6 addr, and MAC.
* this is based on the example in getifaddrs(3) */
int main(int argc, char *argv[]) {
struct ifaddrs *ifaddr, *ifa;
int family, s;
char host[NI_MAXHOST];
if (getifaddrs(&ifaddr) == -1) {
perror("getifaddrs");
exit(EXIT_FAILURE);
}
for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) {
/* get name of interface and its family */
family = ifa->ifa_addr->sa_family;
if (! ((family == AF_INET) || (family == AF_INET6))) continue;
printf("interface %s ", ifa->ifa_name);
printf("family %s ", family==AF_INET?"AF_INET":"AF_INET6");
/* use getnameinfo to get IPv4/v6 address of interface */
s = getnameinfo(ifa->ifa_addr,
(family == AF_INET) ? sizeof(struct sockaddr_in) :
sizeof(struct sockaddr_in6),
host, NI_MAXHOST, NULL, 0, NI_NUMERICHOST);
if (s != 0) {
printf("getnameinfo() failed: %s\n", gai_strerror(s));
continue;
}
printf("address %s ", host);
/* get MAC address */
unsigned char mac[IFHWADDRLEN];
if (get_if_mac(ifa->ifa_name, mac) != 0) {
printf("no MAC info\n");
continue;
}
assert(IFHWADDRLEN == 6);
printf("MAC %2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x\n",
(unsigned)mac[0], (unsigned)mac[1], (unsigned)mac[2],
(unsigned)mac[3], (unsigned)mac[4], (unsigned)mac[5]);
}
freeifaddrs(ifaddr);
exit(EXIT_SUCCESS);
}
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