/* tcp4_10localip.c */

#include <stdio.h> 

#include <string.h> 

#include <netdb.h> 

#include <arpa/inet.h> 

#include <netinet/in.h> 

#include <sys/types.h> 

#include <sys/socket.h> 

#include <sys/ioctl.h> 

#include <net/if.h> 

#include <net/if_arp.h> 

#include <net/ethernet.h> 

#include <signal.h> 

#include <netinet/ip.h> 



struct  in_addr myself, mymask; 

int fd_arp;                 /* socket fd for receive packets */ 

struct  ifreq  ifr;            /* ifr structure */ 

main (int argc, char* argv[]) { 

    char device[32];  /* ethernet device name */ 

    struct sockaddr  from, to; 

    int fromlen; 

    struct sockaddr_in *sin_ptr; 

    u_char *ptr; 

    int n; 

    strcpy(device, "eth0"); 

    if ((fd_arp = socket(AF_INET, SOCK_PACKET, htons(0x0806))) < 0) { 

        perror( "arp socket error"); 

        exit(-1); 

    } 



    strcpy(ifr.ifr_name, device); 

    /* ifr.ifr_addr.sa_family = AF_INET; */ 

    /* get ip address of my interface */ 

    if (ioctl(fd_arp, SIOCGIFADDR, &ifr) < 0) { 

        perror("ioctl SIOCGIFADDR error"); 

        exit(-1); 

    } 

    sin_ptr = (struct sockaddr_in *)&ifr.ifr_addr; 

    myself  = sin_ptr->sin_addr; 

    /* get network mask of my interface */ 

    if (ioctl(fd_arp, SIOCGIFNETMASK, &ifr) < 0) { 

        perror("ioctl SIOCGIFNETMASK error"); 

        exit(-1); 

    } 

    sin_ptr = (struct sockaddr_in *)&ifr.ifr_addr; 

    mymask  = sin_ptr->sin_addr; 

    /* get mac address of the interface */ 

    if (ioctl(fd_arp, SIOCGIFHWADDR, &ifr) < 0) { 

        perror("ioctl SIOCGIFHWADDR error"); 

        exit(-1); 

    } 

    ptr = (u_char *)&ifr.ifr_ifru.ifru_hwaddr.sa_data[0]; 

    printf( "request mac %02x:%02x:%02x:%02x:%02x:%02x, ", 

            *ptr, *(ptr + 1), *(ptr + 2), *(ptr + 3), 

            *(ptr + 4), *(ptr + 5) ); 

    printf( "request netmask  %s ", inet_ntoa(mymask)); 

    printf( "request IP  %s\n", inet_ntoa(myself)); 

}  /* end of main */