wifi ioctl

WIFI ioctl中SIOCSIWSCAN命令从应用程序到内核再到驱动
应用程序中：
ioctl(skfd, SIOCSIWSCAN , &wrq);
其中，#define SIOCSIWSCAN0x8B18

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_defiwctl_handler_def =
{
......
.get_wireless_stats = &iwctl_get_wireless_stats,
.standard= (iw_handler *) iwctl_handler,
......
}

static const iw_handleriwctl_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