ioctl获取接口名称、IP地址、MAC地址、广播地址等

http://blog.markloiseau.com/2012/02/get-network-interfaces-in-c/
http://www.doctort.org/adam/nerd-notes/enumerating-network-interfaces-on-linux.html
http://www.geekpage.jp/en/programming/linux-network/get-ipaddr.php

#include <sys/ioctl.h>

#include <net/if.h>

#include <netinet/in.h>

#include <stdio.h>

#include <arpa/inet.h>



/* 自定义一个结构体存放需要的接口信息。*/

struct ifi_info {

	char *ifi_name;

//	char ifi_name[IFNAMSIZ];		/* interface name, null-terminated */

	struct sockaddr ifi_addr;		/* primary address */

	u_char ifi_haddr[8];			/* hardware address*/

	short ifi_index;				/* interface index */

};



int main(void)

{

    char          buf[1024];

    struct ifconf ifc;

    struct ifreq *ifr;

    int           sck;

    int           nInterfaces;

    int           i;



    struct ifi_info myifi_info[10];



    /* Get a socket handle. */

    sck = socket(AF_INET, SOCK_DGRAM, 0);

    if(sck < 0)

    {

        perror("socket");

        return 1;

    }



    /* Query available interfaces. */

    ifc.ifc_len = sizeof(buf);

    ifc.ifc_buf = buf;

    if(ioctl(sck, SIOCGIFCONF, &ifc) < 0)

    {

        perror("ioctl(SIOCGIFCONF)");

        return 1;

    }



    /* Iterate through the list of interfaces. */

    ifr         = ifc.ifc_req;

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

    for(i = 0; i < nInterfaces; i++)

    {

        struct ifreq *item = &ifr[i];

        myifi_info[i].ifi_name = item->ifr_name;

        myifi_info[i].ifi_addr = item->ifr_addr;



        /* Show the device name and IP address */

        printf("%s: IP %s",

        		myifi_info[i].ifi_name,

               inet_ntoa(((struct sockaddr_in *)&(myifi_info[i].ifi_addr))->sin_addr));



        /* Get the MAC address */

        if(ioctl(sck, SIOCGIFHWADDR, item) < 0)

        {

            perror("ioctl(SIOCGIFHWADDR)");

            return 1;

        }



//      myifi_info.ifi_haddr = &(item->ifr_hwaddr).sa_data;



        /* Get the broadcast address (added by Eric)*/

        if(ioctl(sck, SIOCGIFBRDADDR, item) >= 0)

            printf(", BROADCAST %s", inet_ntoa(((struct sockaddr_in *)&item->ifr_broadaddr)->sin_addr));

        printf("\n");



    }//end for



        return 0;

}