Linux中c语言实现获取wifi状态
Linux中c语言实现获取wifi状态
获取wifi信息有两种方案，参考ifconfig程序使用c语言实现，或者使用命令抓取关键词。
1、c语言实现
废话不多说直接上代码。
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <linux/wireless.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <unistd.h>
#include <arpa/inet.h>
#define NET_PORT 53
#define NET_IP "8.8.8.8" //谷歌DNS
int main()
{
int sockfd;
struct iwreq wreq;
struct iw_statistics stats;
char buffer[32];
int in_len=0;
struct sockaddr_in servaddr;
memset(buffer, 0, 32);
memset(&stats, 0, sizeof(stats));
memset(&wreq, 0, sizeof(wreq));
strcpy(wreq.ifr_name, "wlan0");
if((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) //建立socket，用于接收来自ioctl函数的消息。由于是sock_DGRAM,所以是UDP。如果是SOCK_STREAM,则是TCP。
{
perror("Could not create simple datagram socket");
exit(EXIT_FAILURE);
}
in_len = sizeof(struct sockaddr_in);
/*设置默认服务器的信息*/
servaddr.sin_family = AF_INET;
servaddr.sin_port = htons(NET_PORT);
servaddr.sin_addr.s_addr = inet_addr(NET_IP);
memset(servaddr.sin_zero,0,sizeof(servaddr.sin_zero));
/*connect 函数*/
if(connect(sockfd,(struct sockaddr* )&servaddr,in_len) < 0 )
{
printf("not connect to internet!\n ");
close(sockfd);
return 0;
}else{
printf(" connect ok! \n");
}
//ioctl获取Signal level
wreq.u.data.pointer = &stats;
wreq.u.data.length = sizeof(iw_statistics);
if(ioctl(sockfd, SIOCGIWSTATS, &wreq) == -1)
{
perror("Error performing SIOCGIWSTATS");
close(sockfd);
exit(EXIT_FAILURE);
}else{
// IW_QUAL_DBM表示Level + Noise are dBmm
printf("Signal level%s is %d%s.\n",(stats.qual.updated & IW_QUAL_DBM ? " (in dBm)" :""),(signed char)stats.qual.level,
(stats.qual.updated & IW_QUAL_LEVEL_UPDATED ? " (updated)" :""));
}
//ioctl获取essid
wreq.u.essid.pointer = buffer;//如果不写这行可能会错误
wreq.u.essid.length = 32;
if (ioctl(sockfd,SIOCGIWESSID, &wreq) == -1) {
perror("IOCTL SIOCGIWESSID Failed,error");
exit(2);
}else {
//printf("IOCTL SIOCGIWESSID Successfull\n");
printf("The essid is:%s\n",wreq.u.essid.pointer); //network name
}
close(sockfd);
return 0;
}
首先建立socket，函数原型即：int socket(int domain, int type, int protocol)，再建立connect连接，我是用的谷歌的DNS:8.8.8.8来测试连接外网。如果连接成功后就可获取wifi名字和强度了。
接下来使用ioctl函数，ioctl是设备驱动程序中对设备的I/O通道进行管理的函数。所谓对I/O通道进行管理，就是对设备的一些特性进行控制，它的调用个数如下：
int ioctl(int fd, ind cmd, …)；
其中fd是用户程序打开设备时使用open函数返回的文件标示符，cmd是用户程序对设备的控制命令，至于后面的省略号，那是一些补充参数，一般最多一个，这个参数的有无和cmd的意义相关。
ioctl函数是文件结构中的一个属性分量，就是说如果你的驱动程序提供了对ioctl的支持，用户就可以在用户程序中使用ioctl函数来控制设备的I/O通道。
2、命令抓取方式
FILE* fp=NULL;
char buf[100] = {0};
char command[300] = " sudo iwlist wlan0 scan";
char str1[100];
char str2[100];
char *q = NULL;
memset(str1, '\0', sizeof(str1));
memset(str2, '\0', sizeof(str2));
if((fp = popen(command, "r")) != NULL)
{
// printf("popen command success\n");
while(fgets(buf, sizeof(buf), fp) != NULL)
{
//printf("buf=%s\n", buf);
q = strstr(buf, "ESSID:");
if (q != NULL)
{
// printf("q =NULL\n");
sscanf(q, "ESSID:\"%[^\"]\"", str1);
q = NULL;
}
q = strstr(buf, "Signal level=");
if (q != NULL)
{
// printf("q =NULL\n");
sscanf(q, "Signal level=%[^/]", str2);
q = NULL;
strcat(str1,"");
strcat(str1,str2);
wifilist.append(str1);
}
}
pclose(fp);
}
popen将命令sudo iwlist wlan0 scan通过管道读到fp，fgets函数从指定的流中读取数据，每次读取一行。其原型为：
ioctl查询无线网卡信息
/* -------------------------- 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 */