ioctl查询无线网卡信息
#include<unistd.h>
#include<sys/ioctl.h>
int ioctl( int fd, int request,.../* void *arg */ );
//返回0：成功 -1：出错
//第三个参数总是一个指针，但指针的类型依赖于request参数。
request 参数定义如下：/* -------------------------- IOCTL LIST-------------------------- */
/* Basic operations */
#define SIOCSIWCOMMIT 0x8B00 /* 提交修改结果 */
#define SIOCGIWNAME 0x8B01 /* 获取设备名字 */
#define SIOCSIWNWID 0x8B02 /* 设置网络ID */
#define SIOCGIWNWID 0x8B03 /* 获取网络ID */
#define SIOCSIWFREQ 0x8B04 /* 设置信道（频率） */
#define SIOCGIWFREQ 0x8B05 /* 获取信道（频率） */
#define SIOCSIWMODE 0x8B06 /* 设置网卡模式*/
#define SIOCGIWMODE 0x8B07 /* 获取网卡模式 */
#define SIOCSIWSENS 0x8B08 /* 设置灵敏度(dBm) */
#define SIOCGIWSENS 0x8B09 /* 获取灵敏度 (dBm) */
/* Informative stuff */
#define SIOCSIWRANGE 0x8B0A /* Unused */
#define SIOCGIWRANGE 0x8B0B /* 获取参数范围 */
#define SIOCSIWPRIV 0x8B0C /* Unused */
#define SIOCGIWPRIV 0x8B0D /* 获取网卡特有的ioctl接口 */
#define SIOCSIWSTATS 0x8B0E /* Unused */
#define SIOCGIWSTATS 0x8B0F /* 获取 /proc/net/wireless的stats */
/* Mobile IP support */
#define SIOCSIWSPY 0x8B10 /* 设置spy 地址*/
#define SIOCGIWSPY 0x8B11 /* 获取spy信息（连接质量） */
/* Access Point manipulation */
#define SIOCSIWAP 0x8B14 /* 设置AP的mac地址 */
#define SIOCGIWAP 0x8B15 /* 获取AP的mac地址 */
#define SIOCGIWAPLIST 0x8B17 /* 获取周围Ap信息列表 */
#define SIOCSIWSCAN 0x8B18 /* 开始扫描 */
#define SIOCGIWSCAN 0x8B19 /* 获取扫描信息 */
/* 802.11 specific support */
#define SIOCSIWESSID 0x8B1A /* 设置ESSID */
#define SIOCGIWESSID 0x8B1B /* 获取ESSID */
#define SIOCSIWNICKN 0x8B1C /* 设置节点别名 */
#define SIOCGIWNICKN 0x8B1D /* 获取节点别名 */
/* As the ESSID and NICKN are strings upto 32 bytes long, it doesn't fit
* within the 'iwreq' structure, sowe need to use the 'data' member to
* point to a string in user space,like it is done for RANGE...
* The "flags" memberindicate if the ESSID is active or not (promiscuous).
*/
/* Other parameters useful in 802.11 andsome other devices */
#define SIOCSIWRATE 0x8B20 /* 设置默认传输速率(bps) */
#define SIOCGIWRATE 0x8B21 /* 获取默认传输速率 (bps) */
#define SIOCSIWRTS 0x8B22 /* 设置 RTS/CTS 的临界值(bytes) */
#define SIOCGIWRTS 0x8B23 /* 获取 RTS/CTS 的临界值 (bytes) */
#define SIOCSIWFRAG 0x8B24 /* 设置分片传输的包大小 (bytes) */
#define SIOCGIWFRAG 0x8B25 /* 获取分片传输的包大小 (bytes)*/
#define SIOCSIWTXPOW 0x8B26 /* 设置传输功率 (dBm) */
#define SIOCGIWTXPOW 0x8B27 /* 获取传输功率(dBm) */
#define SIOCSIWRETRY 0x8B28 /* 设置重传次数和生存时间 */
#define SIOCGIWRETRY 0x8B29 /* 获取重传次数和生存时间 */
/* Encoding stuff (scrambling, hardwaresecurity, WEP...) */
#define SIOCSIWENCODE 0x8B2A /* 设置编码模式 */
#define SIOCGIWENCODE 0x8B2B /* 获取编码模式 */
/* Power saving stuff (power management,unicast and multicast) */
#define SIOCSIWPOWER 0x8B2C /* 设置电源管理模式 */
#define SIOCGIWPOWER 0x8B2D /* 获取电源管理模式*/
/* -------------------- DEV PRIVATE IOCTLLIST -------------------- */
/* These 16 ioctl are wireless deviceprivate.
* Each driver is free to use themfor whatever purpose it chooses,
* however the driver *must* exportthe description of those ioctls
* with SIOCGIWPRIV and *must* usearguments as defined below.
* If you don't follow those rules,DaveM is going to hate you (reason :
* it make mixed 32/64bit operationimpossible).
*/
#define SIOCIWFIRSTPRIV 0x8BE0
#define SIOCIWLASTPRIV 0x8BFF
/* Previously, we were usingSIOCDEVPRIVATE, but we now have our
* separate range because ofcollisions with other tools such as
* 'mii-tool'.
* We now have 32 commands, so a bitmore space ;-).
* Also, all 'odd' commands are onlyusable by root and don't return the
* content of ifr/iwr to user (butyou are not obliged to use the set/get
* convention, just use every othertwo command).
* And I repeat : you are not obligedto use them with iwspy, but you
* must be compliant with it.
*/
/* ------------------------- IOCTL STUFF------------------------- */
/* The first and the last (range) */
#define SIOCIWFIRST 0x8B00
#define SIOCIWLAST SIOCIWLASTPRIV /* 0x8BFF */
