【填坑2】获取设备所有网卡的mac地址

生产上的bug：

由于用户删除网卡之后未作重启动作，导致网卡不连续，ip a查看网卡信息前面的序号不连续。

比如：正常是123456，删除4之后成了123 56 。

获取机器所有网卡的mac地址，5 6号网卡信息未读到。

代码1：

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

int getMacInfo()
{
struct ifreq ifr;

int sock = socket(AF_INET, SOCK_DGRAM, 0);
if (sock == -1) {
return -1;
}

int index = 1;
while(1) {

ifr.ifr_ifindex = index++;
if (ioctl(sock, SIOCGIFNAME, &ifr) != 0) {
close(sock);
return 0;
}

if (ioctl(sock, SIOCGIFFLAGS, &ifr) == 0) {
if (! (ifr.ifr_flags & IFF_LOOPBACK)) { // don't count loopback
if (ioctl(sock, SIOCGIFHWADDR, &ifr) == 0) {

printf("%02x:%02x:%02x:%02x:%02x:%02x\n",
(unsigned char)ifr.ifr_hwaddr.sa_data[0],
(unsigned char)ifr.ifr_hwaddr.sa_data[1],
(unsigned char)ifr.ifr_hwaddr.sa_data[2],
(unsigned char)ifr.ifr_hwaddr.sa_data[3],
(unsigned char)ifr.ifr_hwaddr.sa_data[4],
(unsigned char)ifr.ifr_hwaddr.sa_data[5]);
}
}
}
}

close(sock);
return -1;
}

int main(int argc, char **argv)
{
getMacInfo();
return 0;
}

 

又改了一版，强制循环读20次

代码2：

int getMacInfo()
{
struct ifreq ifr;

int sock = socket(AF_INET, SOCK_DGRAM, 0);
if (sock == -1) {
return -1;
}

int index = 1;
while(index<21) {

ifr.ifr_ifindex = index++;

if (ioctl(sock, SIOCGIFNAME, &ifr) != 0) {
continue;
}

if (ioctl(sock, SIOCGIFFLAGS, &ifr) == 0) {
if (! (ifr.ifr_flags & IFF_LOOPBACK)) { // don't count loopback
if (ioctl(sock, SIOCGIFHWADDR, &ifr) == 0) {

printf("%02x:%02x:%02x:%02x:%02x:%02x\n",
(unsigned char)ifr.ifr_hwaddr.sa_data[0],
(unsigned char)ifr.ifr_hwaddr.sa_data[1],
(unsigned char)ifr.ifr_hwaddr.sa_data[2],
(unsigned char)ifr.ifr_hwaddr.sa_data[3],
(unsigned char)ifr.ifr_hwaddr.sa_data[4],
(unsigned char)ifr.ifr_hwaddr.sa_data[5]);
}
}
}
}

close(sock);
return -1;
}

int main(int argc, char **argv)
{
getMacInfo();
return 0;
}

 

这样做不是很完美，后来又出了一版，用ioctl的SIOCGIFCONF参数

代码3：

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

int main()
{

int i = 0;
int sockfd;
struct ifconf ifconf;
char buf[1024];
struct ifreq *ifreq;

ifconf.ifc_len = sizeof(buf);
ifconf.ifc_buf = (caddr_t)buf;

if ((sockfd=socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
perror("socket");
exit(1);
}

ioctl(sockfd, SIOCGIFCONF, &ifconf);

ifreq = (struct ifreq*)buf;
printf("ifconf.ifc_len: %d sizeof(struct ifreq):%d\n", (int)ifconf.ifc_len, (int)sizeof(struct ifreq));
for (i=(ifconf.ifc_len/sizeof(struct ifreq))-1; i>=0; i--) {

if (ioctl(sockfd, SIOCGIFHWADDR, &ifreq[i]) == 0) {
printf("%02x:%02x:%02x:%02x:%02x:%02x\n",
(unsigned char)ifreq[i].ifr_hwaddr.sa_data[0],
(unsigned char)ifreq[i].ifr_hwaddr.sa_data[1],
(unsigned char)ifreq[i].ifr_hwaddr.sa_data[2],
(unsigned char)ifreq[i].ifr_hwaddr.sa_data[3],
(unsigned char)ifreq[i].ifr_hwaddr.sa_data[4],
(unsigned char)ifreq[i].ifr_hwaddr.sa_data[5]);
}

}
close(sockfd);
return 0;
}

这一版获取的mac信息也不全。

网上找的原因：系统接口，通过ioctl  SIOCGIFCONF来获取网卡信息有个问题，就是当我的网卡没能分配到ip时，就会获取不到该网卡信息

 

最后定了一版，就是先从系统文件/proc/net/dev中读出所有的devName，再调用ioctl接口获取mac信息。这下应该没啥问题了。

代码稍后。

 

由于粘的代码，缩进丢失，博客园不会添加代码块，还有本人比较懒。先凑合看看吧。

后期一定优化，下班了。

原文地址：https://www.cnblogs.com/pangkr-linux/p/10420015.html