wifi ioctl

socket的ioctl先看net/socket.c的sock_ioctl

对于无线：
0x8B00 ~ 0x8BFF  调用net/core/dev.c --> dev_ioctl
dev_ioctl中执行到default中，最后调用了wireless_process_ioctl
对wireless_process_ioctl，又跑到了default中，如果有handler，最后到ioctl_standard_call中；
没有handler时，使用老的接口（dev->do_ioctl）。

handler = get_handler(dev, cmd);
   if(handler != NULL) {
    /* Standard and private are not the same */
    if(cmd < SIOCIWFIRSTPRIV)
     return ioctl_standard_call(dev,
           ifr,
           cmd,
           handler);
    else
     return ioctl_private_call(dev,
          ifr,
          cmd,
          handler);
   }
   /* Old driver API : call driver ioctl handler */
   if (dev->do_ioctl) {
    return dev->do_ioctl(dev, ifr, cmd);
   }

有handler时，在具体WIFI驱动中，有类似如下实现：
netdev->wireless_handlers = (struct iw_handler_def *)&iwctl_handler_def;

const struct iw_handler_def iwctl_handler_def =
{
......
 .get_wireless_stats = &iwctl_get_wireless_stats, 
 .standard = (iw_handler *) iwctl_handler,
......
}

static const iw_handler  iwctl_handler[] =
{
 (iw_handler) iwctl_commit,      // SIOCSIWCOMMIT     
......
......
 (iw_handler) iwctl_giwrange,  // SIOCGIWRANGE 
......
......
#if WIRELESS_EXT > 13 
 (iw_handler) iwctl_siwscan,         // SIOCSIWSCAN  
 (iw_handler) iwctl_giwscan,         // SIOCGIWSCAN   
#else 
 (iw_handler) NULL,
 (iw_handler) NULL,
#endif 
......
};

rt_ioctl_siwessid