ethernet.c

在linux9下获得主机hostid的c源代码。

#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;
struct ifreq ifr;

getmac(char *dev)
{
        char device[32];
  struct sockaddr from, to;
  int fromlen;
  struct sockaddr_in *sin_ptr;
  u_char *ptr;
  int n;
  FILE *fp;

  strcpy( device, dev );
  if ( ( fd_arp = socket( AF_INET, SOCK_PACKET, htons( 0x0806 ) ) ) < 0 )
  {
        perror( "arp socket error" );
    return;
  }
  strcpy( ifr.ifr_name, device );
  if ( ioctl( fd_arp, SIOCGIFADDR, &ifr ) < 0 )
  {
    perror( "ioctl SIOCGIFADDR error" );
    return;
  }
  sin_ptr = (struct sockaddr_in *)&ifr.ifr_addr;
  myself = sin_ptr->sin_addr;

// get network mask
  if ( ioctl( fd_arp, SIOCGIFNETMASK, &ifr ) < 0 )
  {
        perror( "ioctl SIOCGIFNETMASK error" );
    return;
  }
  sin_ptr = (struct sockaddr_in *)&ifr.ifr_addr;
  mymask = sin_ptr->sin_addr;

// get mac address
  if ( ioctl( fd_arp, SIOCGIFHWADDR, &ifr ) < 0 )
  {
    perror( "ioctl SIOCGIFHWADDR error" );
    return;
  }
  ptr=(u_char *)&ifr.ifr_ifru.ifru_hwaddr.sa_data[0];
  printf("\nrequest mac %02x:%02x:%02x:%02x:%02x:%02x,",*ptr,*(ptr+1),*(ptr+2),*(ptr+3),*(ptr+4),*(ptr+5));
  printf("\nrequest netmask %s",inet_ntoa(mymask));
  printf("\nrequest IP %s\n",inet_ntoa(myself));

  /*if can find mac address, write it into the /usr/hostid file*/
  if ( ( fp = fopen( "/usr/hostid", "w" ) ) == NULL )
  {
        printf( "Can not create the file!\n" );
        return;
  }
  fprintf( fp, "hostid:%02x%02x%02x%02x%02x%02x1234",*ptr,*(ptr+1),*(ptr+2),*(ptr+3),*(ptr+4),*(ptr+5) );
  fclose( fp );

}
main()
{
        char dev[56];
        int i;

        for (i=0; i<6; i++)
        {
                sprintf( dev, "eth%d", i );
                getmac( dev );
        }
        printf( "File exists /usr/hostid\n" );
}