7/08/2021

C linux get Mac Address

 In my case, I failed to get Mac from eth0 devices.

So I need to check all devices to get Mac address.

This is my solution example code:

(study.marearts.com)


..

#include <sys/ioctl.h>
#include <net/if.h>
#include <unistd.h>
#include <netinet/in.h>
#include <string.h>
#include <stdio.h>
#include <sstream>
#include <string>
#include <iostream>
std::string getMac(){
struct ifreq ifr;
struct ifconf ifc;
char buf[1024];
int success = 0;
int sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
if (sock == -1) { /* handle error*/ };
ifc.ifc_len = sizeof(buf);
ifc.ifc_buf = buf;
if (ioctl(sock, SIOCGIFCONF, &ifc) == -1) { /* handle error */ }
struct ifreq* it = ifc.ifc_req;
const struct ifreq* const end = it + (ifc.ifc_len / sizeof(struct ifreq));
int a=0;
for (; it != end; ++it) {
strcpy(ifr.ifr_name, it->ifr_name);
if (ioctl(sock, SIOCGIFFLAGS, &ifr) == 0) {
if (! (ifr.ifr_flags & IFF_LOOPBACK)) { // don't count loopback
if (ioctl(sock, SIOCGIFHWADDR, &ifr) == 0) {
success = 1;
break;
}
}
}
else {
/* handle error */
return "0";
}
}
unsigned char mac_address[6];
if (success)
{
memcpy(mac_address, ifr.ifr_hwaddr.sa_data, 6);
std::stringstream ss;
std::string target;
char buffer [50];
sprintf (buffer, "%x-%x-%x-%x-%x-%x", mac_address[0], mac_address[1], mac_address[2], mac_address[3], mac_address[4], mac_address[5]);
ss << buffer;
ss >> target;
return target;
}
return "0";
}
int main()
{
std::cout<< getMac() << std::endl;
}

..

Output is

44-a5-6e-63-a4-bb


Thank you.

marearts