Linux下获取所有可用网卡信息

曾经终败给现在 2022-07-17 03:43 232阅读 0赞

在[Linux][]下开发网络程序时，经常会遇到需要取本地网络接口名、[IP][]、[广播][Link 1][地址][Link 2]、子网掩码或者MAC地址等信息的需求，最常见的办法是配合宏SIOCGIFHWADDR、SIOCGIFADDR、SIOCGIFBRDADDR与SIOCGIFNETMASK作为参数调用[函数][Link 3]ioctl分别获得MAC地址、IP地址、广播地址与子网掩码来实现。一次性获取此类信息的[C语言][C]代码实现如下。

\#include <stdio.h>  
\#include <string.h>  
\#include <net/if.h>  
\#include <sys/ioctl.h>  
\#include <arpa/inet.h>  
\#include <errno.h>  
  
int getLocalInfo(void)  
\{  
int fd;  
int interfaceNum = 0;  
struct ifreq buf\[16\];  
struct ifconf ifc;  
struct ifreq ifrcopy;  
char mac\[16\] = \{0\};  
char ip\[32\] = \{0\};  
char broadAddr\[32\] = \{0\};  
char subnetMask\[32\] = \{0\};  
  
if ((fd = socket(AF\_INET, SOCK\_DGRAM, 0)) < 0)  
\{  
perror("socket");  
close(fd);  
return -1;  
\}  
  
ifc.ifc\_len = sizeof(buf);  
ifc.ifc\_buf = (caddr\_t)buf;  
if (!ioctl(fd, SIOCGIFCONF, (char \*)&ifc))  
\{  
interfaceNum = ifc.ifc\_len / sizeof(struct ifreq);  
printf("interface num = %d\\n", interfaceNum);  
while (interfaceNum-- > 0)  
\{  
printf("\\ndevice name: %s\\n", buf\[interfaceNum\].ifr\_name);  
  
//ignore the interface that not up or not runing  
ifrcopy = buf\[interfaceNum\];  
if (ioctl(fd, SIOCGIFFLAGS, &ifrcopy))  
\{  
printf("ioctl: %s \[%s:%d\]\\n", strerror(errno), \_\_FILE\_\_, \_\_LINE\_\_);  
close(fd);  
return -1;  
\}  
  
//get the mac of this interface  
if (!ioctl(fd, SIOCGIFHWADDR, (char \*)(&buf\[interfaceNum\])))  
\{  
memset(mac, 0, sizeof(mac));  
snprintf(mac, sizeof(mac), "%02x%02x%02x%02x%02x%02x",  
(unsigned char)buf\[interfaceNum\].ifr\_hwaddr.sa\_data\[0\],  
(unsigned char)buf\[interfaceNum\].ifr\_hwaddr.sa\_data\[1\],  
(unsigned char)buf\[interfaceNum\].ifr\_hwaddr.sa\_data\[2\],  
(unsigned char)buf\[interfaceNum\].ifr\_hwaddr.sa\_data\[3\],  
(unsigned char)buf\[interfaceNum\].ifr\_hwaddr.sa\_data\[4\],  
(unsigned char)buf\[interfaceNum\].ifr\_hwaddr.sa\_data\[5\]);  
printf("device mac: %s\\n", mac);  
\}  
else  
\{  
printf("ioctl: %s \[%s:%d\]\\n", strerror(errno), \_\_FILE\_\_, \_\_LINE\_\_);  
close(fd);  
return -1;  
\}  
  
//get the IP of this interface  
if (!ioctl(fd, SIOCGIFADDR, (char \*)&buf\[interfaceNum\]))  
\{  
snprintf(ip, sizeof(ip), "%s",  
(char \*)inet\_ntoa(((struct sockaddr\_in \*)&(buf\[interfaceNum\].ifr\_addr))->sin\_addr));  
printf("device ip: %s\\n", ip);  
\}  
else  
\{  
printf("ioctl: %s \[%s:%d\]\\n", strerror(errno), \_\_FILE\_\_, \_\_LINE\_\_);  
close(fd);  
return -1;  
\}  
  
//get the broad address of this interface  
if (!ioctl(fd, SIOCGIFBRDADDR, &buf\[interfaceNum\]))  
\{  
snprintf(broadAddr, sizeof(broadAddr), "%s",  
(char \*)inet\_ntoa(((struct sockaddr\_in \*)&(buf\[interfaceNum\].ifr\_broadaddr))->sin\_addr));  
printf("device broadAddr: %s\\n", broadAddr);  
\}  
else  
\{  
printf("ioctl: %s \[%s:%d\]\\n", strerror(errno), \_\_FILE\_\_, \_\_LINE\_\_);  
close(fd);  
return -1;  
\}  
  
//get the subnet mask of this interface  
if (!ioctl(fd, SIOCGIFNETMASK, &buf\[interfaceNum\]))  
\{  
snprintf(subnetMask, sizeof(subnetMask), "%s",  
(char \*)inet\_ntoa(((struct sockaddr\_in \*)&(buf\[interfaceNum\].ifr\_netmask))->sin\_addr));  
printf("device subnetMask: %s\\n", subnetMask);  
\}  
else  
\{  
printf("ioctl: %s \[%s:%d\]\\n", strerror(errno), \_\_FILE\_\_, \_\_LINE\_\_);  
close(fd);  
return -1;  
\}  
\}  
\}  
else  
\{  
printf("ioctl: %s \[%s:%d\]\\n", strerror(errno), \_\_FILE\_\_, \_\_LINE\_\_);  
close(fd);  
return -1;  
\}  
  
close(fd);  
return 0;  
\}  
  
int main(void)  
\{  
getLocalInfo();  
return 0;  
\}

保存为getmac.c，编译make getmac，执行getmac的结果

interface num = 2  
  
device name: eth0  
device mac: 000a227da213  
device ip: 192.168.2.19  
device broadAddr: 192.1168.255.255  
device subnetMask: 255.255.0.0  
  
device name: lo  
device mac: 000000000000  
device ip: 127.0.0.1  
device broadAddr: 0.0.0.0  
device subnetMask: 255.0.0.0

[Linux]: http://www.cpplive.com/html/tag/linux
[IP]: http://www.cpplive.com/html/tag/ip
[Link 1]: http://www.cpplive.com/html/tag/broadcast
[Link 2]: http://www.cpplive.com/html/tag/address
[Link 3]: http://www.cpplive.com/html/tag/function
[C]: http://www.cpplive.com/html/tag/c-language