linux c 获取mac

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <unistd.h>

void get_mac_addresses() {
    int sockfd;
    struct ifreq ifr;
    struct ifconf ifc;
    char buf[1024];
    int success = 0;

    sockfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
    if (sockfd == -1) {
        perror("socket");
        return;
    }

    ifc.ifc_len = sizeof(buf);
    ifc.ifc_buf = buf;
    if (ioctl(sockfd, SIOCGIFCONF, &ifc) == -1) {
        perror("ioctl(SIOCGIFCONF)");
        close(sockfd);
        return;
    }

    struct ifreq* it = ifc.ifc_req;
    const struct ifreq* const end = it + (ifc.ifc_len / sizeof(struct ifreq));

    for (; it != end; ++it) {
        strcpy(ifr.ifr_name, it->ifr_name);
        if (ioctl(sockfd, SIOCGIFFLAGS, &ifr) == 0) {
            if (! (ifr.ifr_flags & IFF_LOOPBACK)) { // don't count loopback
                if (ioctl(sockfd, SIOCGIFHWADDR, &ifr) == 0) {
                    success = 1;
                    unsigned char* mac = (unsigned char*)ifr.ifr_hwaddr.sa_data;
                    printf("Interface: %s, MAC Address: %02X:%02X:%02X:%02X:%02X:%02X\n",
                           ifr.ifr_name, mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
                } else {
                    perror("ioctl(SIOCGIFHWADDR)");
                }
            }
        } else {
            perror("ioctl(SIOCGIFFLAGS)");
        }
    }

    if (success == 0) {
        printf("No MAC addresses found.\n");
    }

    close(sockfd);
}

int main() {
    get_mac_addresses();
    return 0;
}