用C语言得到Linux本机的IP地址2

 include <stdio.h>

#include <sys/types.h>

#include <sys/param.h>

#include <sys/ioctl.h>

#include <sys/socket.h>

#include <net/if.h>

#include <netinet/in.h>

#include <net/if_arp.h>

#define MAXINTERFACES 16

main (argc, argv)

register int argc;

register char *argv[];

{

register int fd, intrface, retn = 0;

struct ifreq buf[MAXINTERFACES];

struct arpreq arp;

struct ifconf ifc;

if ((fd = socket (AF_INET, SOCK_DGRAM, 0)) >= 0) {

ifc.ifc_len = sizeof buf;

ifc.ifc_buf = (caddr_t) buf;

if (!ioctl (fd, SIOCGIFCONF, (char *) &ifc)) {

intrface = ifc.ifc_len / sizeof (struct ifreq);

printf("interface num is intrface=%d\n\n\n",intrface);

while (intrface-- > 0)

{

printf ("net device %s\n", buf[intrface].ifr_name);

/*Jugde whether the net card status is promisc*/

if (!(ioctl (fd, SIOCGIFFLAGS, (char *) &buf[intrface]))) {

if (buf[intrface].ifr_flags & IFF_PROMISC) {

puts ("the interface is PROMISC");

retn++;

}

} else {

char str[256];

sprintf (str, "cpm: ioctl device %s", buf[intrface].ifr_name);

perror (str);

}

/*Jugde whether the net card status is up*/

if (buf[intrface].ifr_flags & IFF_UP) {

puts("the interface status is UP");

}

else {

puts("the interface status is DOWN");

}

/*Get IP of the net card */

if (!(ioctl (fd, SIOCGIFADDR, (char *) &buf[intrface])))

{

puts ("IP address is:");

puts(inet_ntoa(((struct sockaddr_in*)(&buf[intrface].ifr_addr))->sin_addr));

puts("");

//puts (buf[intrface].ifr_addr.sa_data);

}

else {

char str[256];

sprintf (str, "cpm: ioctl device %s", buf[intrface].ifr_name);

perror (str);

}

/*Get HW ADDRESS of the net card */

if (!(ioctl (fd, SIOCGIFHWADDR, (char *) &buf[intrface])))

{

puts ("HW address is:");

printf("%02x:%02x:%02x:%02x:%02x:%02x\n",

(unsigned char)buf[intrface].ifr_hwaddr.sa_data[0],

(unsigned char)buf[intrface].ifr_hwaddr.sa_data[1],

(unsigned char)buf[intrface].ifr_hwaddr.sa_data[2],

(unsigned char)buf[intrface].ifr_hwaddr.sa_data[3],

(unsigned char)buf[intrface].ifr_hwaddr.sa_data[4],

(unsigned char)buf[intrface].ifr_hwaddr.sa_data[5]);

puts("");

puts("");

}

else {

char str[256];

sprintf (str, "cpm: ioctl device %s", buf[intrface].ifr_name);

perror (str);

}

}

} else

perror ("cpm: ioctl");

} else

perror ("cpm: socket");

close (fd);

return retn;

}