基于wpa_supplicant库的WIFI连接功能实现--wpa_cli命令代码改写

上一篇博客我们一起看了怎样使用wpas的命令后，接下来就利用这些命令来实现我们的代码。这些命令的实现都在wpa_cli.c文件中，以status命令为例，发生如下调用：

static int wpa_cli_cmd_status(struct wpa_ctrl *ctrl, int argc, char *argv[])
{
    int verbose = argc > 0 && os_strcmp(argv[0], "verbose") == 0;
    return wpa_ctrl_command(ctrl, verbose ? "STATUS-VERBOSE" : "STATUS");
}

wpa_ctrl_command(struct wpa_ctrl *ctrl, char *cmd)
    _wpa_ctrl_command(ctrl, cmd, 1);
        char buf[2048];
        wpa_ctrl_request(ctrl, cmd, os_strlen(cmd), buf,                                    
                                &len,wpa_cli_msg_cb);
        if (print)
            printf("%s", buf);

从上面可以看出，最终是调用wpa_ctrl_request函数完成命令，而最终结果是存在buf里，通过函数参数print来觉得是否输出到终端。所以我们最终需要取得的结果就是buf，只要拿到buf内容，我们就可以分析其内容实现我们需要的代码。为了实现上述目的，需要对源码进行下修改：我们把输出buf作为参数传入_wpa_ctrl_command函数，这样就可以拿到输出内容了。改写后代码如下：

static int wpa_ctrl_command(struct wpa_ctrl *ctrl, char *buf,  const char *cmd)
{
    return _wpa_ctrl_command(ctrl, buf, cmd, 0);
}

static int _wpa_ctrl_command(struct wpa_ctrl *ctrl, char *buf, const char *cmd, int print)
{
    char ret_buf[2048];
    int ret;
    size_t ret_len;

    ret_len = sizeof(ret_buf) - 1;
    ret = wpa_ctrl_request(ctrl, cmd, strlen(cmd), ret_buf, &ret_len,
                           wpa_cli_msg_cb);
    if (ret == -2)
    {
        printf("'%s' command timed out.\n", cmd);
        return -2;
    }
    else if (ret < 0)
    {
        printf("'%s' command failed.\n", cmd);
        return -1;
    }

    ret_buf[ret_len] = '\0';
    memcpy(buf, ret_buf, 2048);

    if (print)
    {
        ret_buf[ret_len] = '\0';
        printf("%s", ret_buf);
    }
    return 0;
}

static void wpa_cli_msg_cb(char *msg, size_t len)
{
    printf("%s\n", msg);
}

对于各个命令呢，我们同样需要加入buf，还是以status为例：

static int wpa_cli_cmd_status(struct wpa_ctrl *ctrl, char *buf,  int argc, char *argv[])
{
    int verbose = argc > 0 && strcmp(argv[0], "verbose") == 0;
    return wpa_ctrl_command(ctrl, buf, verbose ? "STATUS-VERBOSE" : "STATUS");
}

这样各个命令就达到了我们的目的。最后我们对命令进行一下封装，方便统一管理。

#define CFG_MAXARGS 10

/**
 * @brief 对wpa_supplicant中处理命令进行封装
 */
class HanleCmd : public QObject
{
    Q_OBJECT
public:
    HanleCmd();
    void printCmd();
    int hanleCmd(struct wpa_ctrl *ctrl, char *buf, char *cmd);

private:
    //命令封装
    struct wpa_cli_cmd
    {
        const char *cmd;  //命令名称
        int (*handler)(struct wpa_ctrl *ctrl, char *buf, int argc, char *argv[]);  //命令处理函数
    };

    QList listCmd;  //命令链表

    //私有函数
    void addCmd();
    int wpaRequest(struct wpa_ctrl *ctrl, char *buf, int argc, char *argv[]);
    int parseLine (char *line, char *argv[]);
};

HanleCmd::HanleCmd()
{
    qDebug("init cmd list");
    addCmd();
}

void HanleCmd::addCmd()
{
    struct wpa_cli_cmd cmd;

    //状态命令
    cmd.cmd = "status";
    cmd.handler = wpa_cli_cmd_status;
    listCmd.append(cmd);

    //扫描命令
    cmd.cmd = "scan";
    cmd.handler = wpa_cli_cmd_scan;
    listCmd.append(cmd);

    //扫描结果命令
    cmd.cmd = "scan_results";
    cmd.handler = wpa_cli_cmd_scan_results;
    listCmd.append(cmd);

    //选择AP命令
    cmd.cmd = "select_network";
    cmd.handler = wpa_cli_cmd_select_network;
    listCmd.append(cmd);

    //增加AP命令
    cmd.cmd = "add_network";
    cmd.handler = wpa_cli_cmd_add_network;
    listCmd.append(cmd);

    //列出配置文件中已经保存的AP信息
    cmd.cmd = "list_network";
    cmd.handler = wpa_cli_cmd_list_networks;
    listCmd.append(cmd);

    //设置AP
    cmd.cmd = "set_network";
    cmd.handler = wpa_cli_cmd_set_network;
    listCmd.append(cmd);

    //移除AP
    cmd.cmd = "remove_network";
    cmd.handler = wpa_cli_cmd_remove_network;
    listCmd.append(cmd);

    //使能某个AP
    cmd.cmd = "enable_network";
    cmd.handler = wpa_cli_cmd_enable_network;
    listCmd.append(cmd);

    //关闭某个AP
    cmd.cmd = "disable_network";
    cmd.handler = wpa_cli_cmd_disable_network;
    listCmd.append(cmd);

    //保存配置
    cmd.cmd = "save_config";
    cmd.handler = wpa_cli_cmd_save_config;
    listCmd.append(cmd);
}

int HanleCmd::parseLine (char *line, char *argv[])
{
    int nargs = 0;

    while (nargs < CFG_MAXARGS)
    {

        /* skip any white space */
        while ((*line == ' ') || (*line == '\t'))
        {
            ++line;
        }

        if (*line == '\0')      /* end of line, no more args    */
        {
            argv[nargs] = NULL;
            return (nargs);
        }

        argv[nargs++] = line;   /* begin of argument string */

        /* find end of string */
        while (*line && (*line != ' ') && (*line != '\t'))
        {
            ++line;
        }

        if (*line == '\0')      /* end of line, no more args    */
        {
            argv[nargs] = NULL;
            return (nargs);
        }

        *line++ = '\0';     /* terminate current arg     */
    }

    return (nargs);
}

int HanleCmd::hanleCmd(struct wpa_ctrl *ctrl, char *buf, char *cmd)
{
    int argc;
    char bufTmp[1024];
    char *argv[CFG_MAXARGS];

    strncpy(bufTmp, cmd, 1024);
    bufTmp[1023] = '\0';

    argc = parseLine(bufTmp, argv);
    return wpaRequest(ctrl, buf, argc, argv);
}

封装完毕后，只需要在执行某个命令时候调用如下代码即可：

char buf[2048];
handleCmd->hanleCmd(ctrl_conn, buf,  "status");

这样buf中存入的就是status命令的结果了。

至于参数中的ctrl_conn是底层的操作接口，需要读者自己去分析下wpa_cli的源码，这里只贴一下代码：

int WifiService::initWpa()
{
    qDebug()<<"initWpa";
    //1.变量初始化
    int conectNum = 0;
    ctrl_iface = NULL;
    ctrl_conn = NULL;
    monitor_conn = NULL;
    ctrl_iface_dir = strdup("/var/run/wpa_supplicant");

    //2.与wpa_supplicant建立连接
    while(true)
    {
        wpa_cli_get_default_ifname();
        if(ctrl_iface == NULL){
            qDebug("failed to wpa_cli_get_default_ifname");
            return -1;
        }

        wpa_cli_open_connection(ctrl_iface);
        if (ctrl_conn || monitor_conn){  //ActionThread未启用情况下只用ctrl_conn就可以
            qDebug("wpa_supplicant connection established");
            break;
        }else{
            if(conectNum++ >=2){  //最多试三次
                qDebug("wpa_supplicant connection established err");
                return -1;
            }
            qDebug("wpa_supplicant connection established err, we will try agin");
            usleep(10000);
            continue;
        }
    }
    return 0;
}