根据网卡名获取IP地址，以及掩码地址

nterface name is something like “eth0″ and the ip address of the interface can be retrieved using the ioctl function.
Here is a simple piece of code that demonstrates how :

Code

1	#include <stdio.h>

2	#include <string.h>

3	#include <sys/types.h>

4	#include <sys/socket.h>

5	#include <sys/ioctl.h>

6	#include <netinet/in.h>

7	#include <net/if.h>

8	#include <unistd.h>

9	#include <arpa/inet.h>

10

11	int main()

12

{

13

int fd;

14	struct ifreq ifr;

15

16	char iface[] = "eth0";

17

18	fd = socket(AF_INET, SOCK_DGRAM, 0);

19

20	//Type of address to retrieve - IPv4 IP address

21	ifr.ifr_addr.sa_family = AF_INET;

22

23	//Copy the interface name in the ifreq structure

24	strncpy(ifr.ifr_name , iface , IFNAMSIZ-1);

25

26	ioctl(fd, SIOCGIFADDR, &ifr);

27

28	close(fd);

29

30	//display result

31	printf("%s - %s\n" , iface , inet_ntoa(( (struct sockaddr_in *)&ifr.ifr_addr )->sin_addr) );

32

33

return 0;

34

}

Output

1	$ gcc ioctl.c && ./a.out

2	eth0 - 192.168.0.6

The socket used can be a TCP socket (SOCK_STREAM) as well.

If you also need the netmask then use the SIOCGIFNETMASK value in ioctl like this :

1	#include <stdio.h>

2	#include <string.h>

3	#include <sys/socket.h>

4	#include <sys/ioctl.h>

5	#include <net/if.h>

6	#include <unistd.h>

7	#include <arpa/inet.h>

8

9	int main()

10

{

11

int fd;

12	struct ifreq ifr;

13

14	char iface[] = "eth0";

15

16	fd = socket(AF_INET, SOCK_DGRAM, 0);

17

18	//Type of address to retrieve - IPv4 IP address

19	ifr.ifr_addr.sa_family = AF_INET;

20

21	//Copy the interface name in the ifreq structure

22	strncpy(ifr.ifr_name , iface , IFNAMSIZ-1);

23

24	//get the ip address

25	ioctl(fd, SIOCGIFADDR, &ifr);

26

27	//display ip

28	printf("IP address of %s - %s\n" , iface , inet_ntoa(( (struct sockaddr_in *)&ifr.ifr_addr )->sin_addr) );

29

30	//get the netmask ip

31	ioctl(fd, SIOCGIFNETMASK, &ifr);

32

33	//display netmask

34	printf("Netmask of %s - %s\n" , iface , inet_ntoa(( (struct sockaddr_in *)&ifr.ifr_addr )->sin_addr) );

35

36	close(fd);

37

38

return 0;

39

}

Output :

view source

print?

1	$ gcc ioctl.c && ./a.out

2	IP address of eth0 - 192.168.0.6

3	Netmask of eth0 - 255.255.255.0