linux获得网卡信息

 #define MAX_INTERFACE         64
 
 int showifs()
 {
     int i;
     int rc;
     int sock;
     int ifnum;
     struct ifreq ifr[MAX_INTERFACE];
 //    struct arpreq arp;
     struct ifconf ifc;
 
     sock = socket ( AF_INET, SOCK_DGRAM, IPPROTO_UDP );
     if ( sock == - )
     {
         return -;
     }
 
     ifc.ifc_len = sizeof( ifr );
     ifc.ifc_buf = ( caddr_t ) ifr;
     rc = ioctl ( sock, SIOCGIFCONF, &ifc );
     if ( rc == - )
     {
         close( sock );
         return -;
     }
 
     ifnum = ifc.ifc_len / sizeof ( struct ifreq );
     fprintf( stdout, "ifnum=[%d]\n======================================\n", ifnum );
     for ( i = ; i < ifnum; i ++ )
     {
         fprintf( stdout, "ifname [%s]\n", ifr[i].ifr_name );
 
         //status
         rc = ioctl( sock, SIOCGIFFLAGS, ifr + i );
         if ( rc != - )
         {
             if ( ifr[i].ifr_flags & IFF_PROMISC )
             {
                 fprintf( stdout, "PROMISC=TRUE\n" );
             }
             else
             {
                 fprintf( stdout, "PROMISC=FALSE\n" );
             }
 
             if ( ifr[i].ifr_flags & IFF_UP )
             {
                 fprintf( stdout, "UP=TRUE\n" );
             }
             else
             {
                 fprintf( stdout, "UP=FALSE\n" );
             }
         }
 
         //ip
         rc = ioctl ( sock, SIOCGIFADDR, ifr + i );
         if ( rc != - )
         {
             fprintf( stdout, "IP=%s\n", inet_ntoa( ( ( struct sockaddr_in* )( &ifr[i].ifr_addr ) )->sin_addr ) );
         }
 
         //netmask
         rc = ioctl ( sock, SIOCGIFNETMASK, ifr + i );
         if ( rc != - )
         {
             fprintf( stdout, "NETMASK=%s\n", inet_ntoa( ( ( struct sockaddr_in* )( &ifr[i].ifr_netmask  ) )->sin_addr ) );
         }
 
         //broadcast
         rc = ioctl ( sock, SIOCGIFBRDADDR, ifr + i );
         if ( rc != - )
         {
             fprintf( stdout, "BROADCAST=%s\n", inet_ntoa( ( ( struct sockaddr_in* )( &ifr[i].ifr_broadaddr ) )->sin_addr ) );
         }
 
         //mac
         rc = ioctl ( sock, SIOCGIFHWADDR, ifr + i );
         if ( rc != - )
         {
             fprintf( stdout, "%02x:%02x:%02x:%02x:%02x:%02x\n",
                      ( unsigned char )ifr[i].ifr_hwaddr.sa_data[],
                      ( unsigned char )ifr[i].ifr_hwaddr.sa_data[],
                      ( unsigned char )ifr[i].ifr_hwaddr.sa_data[],
                      ( unsigned char )ifr[i].ifr_hwaddr.sa_data[],
                      ( unsigned char )ifr[i].ifr_hwaddr.sa_data[],
                      ( unsigned char )ifr[i].ifr_hwaddr.sa_data[] );
         }
     }
 
     close( sock );
     return ;
 }