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分类: Android平台

2014-07-16 19:39:26

Android下实现非启动界面Wifi连接

http://yangyangzhao.blog.163.com/blog/static/175816366201011412949131/


Android的网络功能和一般的linux并无太大的区别,我原来以为在Android上连接网络和普通的linux连接网络没有很大区别,事实上区别还是有一些的。

由于项目的需要,我的目标是在Android的界面没有启动之前连接wifi,于是本来的期待是直接在init.rc中加入一些脚本调用即可,但研究了一会儿发现没有那么简单。

首先要感谢anly_jun@baidu贴吧的几篇博文,从http://hi.baidu.com/anly_jun/blog/item/8ecb92d593d144cf50da4b6e.html开始,一共有七篇关于Android Wifi模块分析,其中有大量博主自己使用UML工具画的调用讲解,对于理解Android Wifi工作机制还是有很用的。其中最重要的是下面这几幅图。

Android下实现非启动界面Wifi连接 - angelbear - angelbear的博客(转自http://hi.baidu.com/anly_jun/blog/item/65e26e117e09ebcda6ef3f56.html

在 想要对wifi硬件动作之前,需要做两件事情,一是要load wifi的driver,而是要打开wpa_supplicant,其实如果是连接没有加密的wifi,没有必要打开wpa_supplicant,但是 为了讲问题化为熟知的问题,此处还是先按照提示调用wifi_load_driver()和wifi_start_supplicant()

按照上面的提示写出来的初始化代码如下:

int init_stage() {
    // load the wifi driver: insmod .ko
    int ret = wifi_load_driver();
    if(ret < 0) {
        LOGE("Failed to load Wi-Fi driver. %s",strerror(errno));
        return -1;
    }

    // start wpa_supplicant
    ret =  wifi_start_supplicant();
    if(ret < 0) {
        LOGE("Failed to start supplicant daemon. %s",strerror(errno));
        return -1;
    }
    return 0;
}

接 下来,便是连接的过程了,经过上面的步骤,wifi的driver已经载入,wpa_supplicant也已经打开,那咱们就可以开始连接无线了吧。后 来证实这是错误的,因为anly_jun的这篇Android wifi分析的粒度只在Java层面的函数级别,因此有一些细节并没有提到。在下面我会提到这些细节。

按照一般的linux中连接 wifi的步骤,这时候就可以直接调用一个程序来连接某个ssid的无线网络,然后调用dhcpd来分配ip了,我之前在eeepc上连接wifi就非常 简单,调用iwconfig [ssid],再调用dhcpd就可以了。但很遗憾,Android上并没有iwconfig这样方便的工具。

这下线索似乎就断了,天无绝人之路,既然在Android的Java code中都可以添加一个无线网络并且连接,那我们就去Android的Java源代码中找一找。在Android中,程序员是使用WifiManager这个类来进行Wifi操作的,其中关于添加一个网络的代码如下:

/**
* Add a new network description to the set of configured networks.
* The {@code networkId} field of the supplied configuration object
* is ignored.
*


* The new network will be marked DISABLED by default. To enable it,
* called {@link #enableNetwork}.
*
* @param config the set of variables that describe the configuration,
*            contained in a {@link WifiConfiguration} object.
* @return the ID of the newly created network description. This is used in
*         other operations to specified the network to be acted upon.
*         Returns {@code -1} on failure.
*/
public int addNetwork(WifiConfiguration config) {
    if (config == null) {
        return -1;
    }
    config.networkId = -1;
    return addOrUpdateNetwork(config);
}

/**
* Internal method for doing the RPC that creates a new network description
* or updates an existing one.
*
* @param config The possibly sparse object containing the variables that
*         are to set or updated in the network description.
* @return the ID of the network on success, {@code -1} on failure.
*/
private int addOrUpdateNetwork(WifiConfiguration config) {
    try {
        return mService.addOrUpdateNetwork(config);
    } catch (RemoteException e) {
        return -1;
    }
}

看其中确实是调用了service的函数,于是又在frameworks/base/services/java/com/android/server/WifiService.java中找到了有关增加一个网络配置的相关代码

/**
* see {@link android.net.wifi.WifiManager#addOrUpdateNetwork(WifiConfiguration)}
* @return the supplicant-assigned identifier for the new or updated
* network if the operation succeeds, or {@code -1} if it fails
*/
public int addOrUpdateNetwork(WifiConfiguration config) {
    enforceChangePermission();

    /*
     * If the supplied networkId is -1, we create a new empty
     * network configuration. Otherwise, the networkId should
     * refer to an existing configuration.
     */
    int netId = config.networkId;
    boolean newNetwork = netId == -1;
    boolean doReconfig = false;
    // networkId of -1 means we want to create a new network
    synchronized (mWifiStateTracker) {
        if (newNetwork) {
            netId = mWifiStateTracker.addNetwork();
            if (netId < 0) {
                if (DBG) {
                    Slog.d(TAG, "Failed to add a network!");
                }
                return -1;
            }
            doReconfig = true;
        }
        mNeedReconfig = mNeedReconfig || doReconfig;
    }

    setVariables: {
        /*
         * Note that if a networkId for a non-existent network
         * was supplied, then the first setNetworkVariable()
         * will fail, so we don't bother to make a separate check
         * for the validity of the ID up front.
         */
        if (config.SSID != null &&
                !mWifiStateTracker.setNetworkVariable(
                    netId,
                    WifiConfiguration.ssidVarName,
                    config.SSID)) {
            if (DBG) {
                Slog.d(TAG, "failed to set SSID: "+config.SSID);
            }
            break setVariables;
        }

        if (config.BSSID != null &&
                !mWifiStateTracker.setNetworkVariable(
                    netId,
                    WifiConfiguration.bssidVarName,
                    config.BSSID)) {
            if (DBG) {
                Slog.d(TAG, "failed to set BSSID: "+config.BSSID);
            }
            break setVariables;
        }

我们来到frameworks/base/wifi/java/android/net/wifi/WifiStateTracker.java中,看看addNetwork和setNetworkVariable函数都是什么样的。

/**
* Add a network
*
* @return network id of the new network
*/
public synchronized int addNetwork() {
    if (mWifiState.get() != WIFI_STATE_ENABLED) {
        return -1;
    }
    return WifiNative.addNetworkCommand();
}

/**
* Set network setting by name
*
* @param netId network id of the network
* @param name network variable key
* @param value network variable value
* @return {@code true} if the operation succeeds, {@code false} otherwise
*/
public synchronized boolean setNetworkVariable(int netId, String name, String value) {
    if (mWifiState.get() != WIFI_STATE_ENABLED) {
        return false;
    }
    return WifiNative.setNetworkVariableCommand(netId, name, value);
}

似乎WifiNative就应该是最终boss了,于是来到frameworks/base/wifi/java/android/net/wifi/WifiNative.java中一看,这两个函数都是这么定义的。
 
public native static int addNetworkCommand();

public native static boolean setNetworkVariableCommand(int netId, String name, String value);
 
熟悉Android NDK开发的朋友都应该知道,这里的函数都是通过jni链接到c/c++代码中,于是我们稍微花了一点时间,找到了这个函数所对应的frameworks/base/core/jni/android_net_wifi_Wifi.cpp
 
static int doCommand(const char *cmd, char *replybuf, int replybuflen)
{
    size_t reply_len = replybuflen - 1;

    if (::wifi_command(cmd, replybuf, &reply_len) != 0)
        return -1;
    else {
        // Strip off trailing newline
        if (reply_len > 0 && replybuf[reply_len-1] == '\n')
            replybuf[reply_len-1] = '\0';
        else
            replybuf[reply_len] = '\0';
        return 0;
    }
}

static jint doIntCommand(const char *cmd)
{
    char reply[256];

    if (doCommand(cmd, reply, sizeof(reply)) != 0) {
        return (jint)-1;
    } else {
        return (jint)atoi(reply);
    }
}

static jboolean doBooleanCommand(const char *cmd, const char *expect)
{
    char reply[256];

    if (doCommand(cmd, reply, sizeof(reply)) != 0) {
        return (jboolean)JNI_FALSE;
    } else {
        return (jboolean)(strcmp(reply, expect) == 0);
    }
}

……

static jint android_net_wifi_addNetworkCommand(JNIEnv* env, jobject clazz)
{
    return doIntCommand("ADD_NETWORK");
}

static jboolean android_net_wifi_setNetworkVariableCommand(JNIEnv* env,
                                                           jobject clazz,
                                                           jint netId,
                                                           jstring name,
                                                           jstring value)
{
    char cmdstr[256];
    jboolean isCopy;

    const char *nameStr = env->GetStringUTFChars(name, &isCopy);
    const char *valueStr = env->GetStringUTFChars(value, &isCopy);

    if (nameStr == NULL || valueStr == NULL)
        return JNI_FALSE;

    int cmdTooLong = snprintf(cmdstr, sizeof(cmdstr), "SET_NETWORK %d %s %s",
                 netId, nameStr, valueStr) >= (int)sizeof(cmdstr);

    env->ReleaseStringUTFChars(name, nameStr);
    env->ReleaseStringUTFChars(value, valueStr);

    return (jboolean)!cmdTooLong && doBooleanCommand(cmdstr, "OK");
}

……

// ----------------------------------------------------------------------------

/*
* JNI registration.
*/
static JNINativeMethod gWifiMethods[] = {
    /* name, signature, funcPtr */

    { "loadDriver", "()Z",  (void *)android_net_wifi_loadDriver },
    { "unloadDriver", "()Z",  (void *)android_net_wifi_unloadDriver },
    { "startSupplicant", "()Z",  (void *)android_net_wifi_startSupplicant },
    { "stopSupplicant", "()Z",  (void *)android_net_wifi_stopSupplicant },
    { "connectToSupplicant", "()Z",  (void *)android_net_wifi_connectToSupplicant },
    { "closeSupplicantConnection", "()V",  (void *)android_net_wifi_closeSupplicantConnection },

    { "listNetworksCommand", "()Ljava/lang/String;",
        (void*) android_net_wifi_listNetworksCommand },
    { "addNetworkCommand", "()I", (void*) android_net_wifi_addNetworkCommand },
    { "setNetworkVariableCommand", "(ILjava/lang/String;Ljava/lang/String;)Z",
        (void*) android_net_wifi_setNetworkVariableCommand },
    { "getNetworkVariableCommand", "(ILjava/lang/String;)Ljava/lang/String;",
        (void*) android_net_wifi_getNetworkVariableCommand },
……
 
看 来这下终于找到干活儿的函数了,可喜可贺,于是我们得出结论:在Android中,要连上一个无线网络,首先需要添加一个网络,然后设置这个网络的配置, 而这些步骤实际上都是通过向wpa_supplicant发送命令实现的。命令的格式例外的很简单,比如添加一个网络配置是ADD_NETWORK,设置 一个网络配置是SET_NETWORK [netId] [varName] [var]。于是根据Java代码我写出了配置环节的代码。
int config_stage(){   
    // Add a network config to supplicant mode
    int networkId = doIntCommand("ADD_NETWORK"); // Add a new network id
    if(networkId < 0) {
        LOGE("Failed to add a network configuration. %s",strerror(errno));
        return -1;
    }

    LOGE("Add a network %d",networkId);

    // set the ssid of the destination wifi adhoc
    char cmdstr[256];
    snprintf(cmdstr, sizeof(cmdstr), "SET_NETWORK %d %s %s",networkId, SSID_NAME, SSID);
    if(!doBooleanCommand(cmdstr,"OK")) {
        LOGE("Failed to set network %d configuration ssid. %s", networkId, strerror(errno));
        return -1;
    }
    return networkId;
}
添 加了一个配置的网络之后,选择某个网络配置的命令是SELECT_NETWORK [netId]。在SELECT_NETWORK之后,wpa_supplicant就尝试和该ssid的AP进行associate操作,在 associate之后便调用dhcpd获取ip。SELECT_NETWORK是立即返回的函数,那么何以得知已经和无线AP连接上了 呢?Android的界面里面连接/断开Wifi都是可以被接受到的事件,在WifiStateTracker中我们看到是由WifiMonitor来监 听由wpa_supplicant发过来的消息的,于是我们来到framework/base/wifi/java/android/net/wifi /WifiMonitor.java,看到其中接受消息的Monitor线程
 
class MonitorThread extends Thread {
    public MonitorThread() {
        super("WifiMonitor");
    }

    public void run() {

        if (connectToSupplicant()) {
            // Send a message indicating that it is now possible to send commands
            // to the supplicant
            mWifiStateTracker.notifySupplicantConnection();
        } else {
            mWifiStateTracker.notifySupplicantLost();
            return;
        }

        //noinspection InfiniteLoopStatement
        for (;;) {
            String eventStr = WifiNative.waitForEvent();

            // Skip logging the common but mostly uninteresting scan-results event
            if (Config.LOGD && eventStr.indexOf(scanResultsEvent) == -1) {
                Log.v(TAG, "Event [" + eventStr + "]");
            }
            if (!eventStr.startsWith(eventPrefix)) {
                if (eventStr.startsWith(wpaEventPrefix) &&
                        0 < eventStr.indexOf(passwordKeyMayBeIncorrectEvent)) {
                    handlePasswordKeyMayBeIncorrect();
                }
                continue;
            }

            String eventName = eventStr.substring(eventPrefixLen);
            int nameEnd = eventName.indexOf(' ');
            if (nameEnd != -1)
                eventName = eventName.substring(0, nameEnd);
            if (eventName.length() == 0) {
                if (Config.LOGD) Log.i(TAG, "Received wpa_supplicant event with empty event name");
 
 
WifiNative.wairForEvent 在wifi.c中对应的函数是wifi_wait_event(),用来阻塞的等待wpa_supplicant发来的消息。当 wpa_supplicant连接上之后,便会发出一个CONTROL-EVENT-CONNECTED的消息,只要截获这个消息,我们便可以进行 dhcp的操作了。
基于以上的考虑,我写了connect阶段的代码。这里我偷了一下懒,没有仔细的去分析过来的命令,只是匹配到有CONNECTED的命令,就当已经连接上了。

#define CONNECTED "CONNECTED"
int connect_stage(int networkId) {
    char cmdstr[256];
    // enable the network
    snprintf(cmdstr, sizeof(cmdstr), "SELECT_NETWORK %d",networkId);
    if(!doBooleanCommand(cmdstr,"OK")) {
        LOGE("Failed to select network %d. %s", networkId, strerror(errno));
        return -1;
    }

    // wait for connect
    char buf[256];
    while(1) {
        int nread = wifi_wait_for_event(buf, sizeof(buf));
        if(nread > 0) {
            LOGE("receive buf:\n %s\n",buf);
            if(strstr(buf,CONNECTED) > 0) {
                break;
            }
            // XXX danger of not going out of the loop!!!
        }
        continue;
    }
    return 0;
}

在WifiStateTracer中我还找到了负责dhcp的DhcpHandler,按照其中的函数写了dhcp阶段的代码

int dhcp_stage(){
    int result;
    in_addr_t ipaddr, gateway, mask, dns1, dns2, server;
    uint32_t lease;

    char ifname[256];
    char mDns1Name[256];
    char mDns2Name[256];
    property_get("wifi.interface", ifname ,"eth0");
    snprintf(mDns1Name, sizeof(mDns1Name), "net.%s.dns1",ifname);
    snprintf(mDns2Name, sizeof(mDns2Name), "net.%s.dns2",ifname);

    result = dhcp_do_request(ifname, &ipaddr, &gateway, &mask, &dns1, &dns2, &server, &lease);
    if(result != 0) {
        LOGE("Failed to dhcp on interface %s. %s", ifname, strerror(errno));
        return -1;
    }
    struct in_addr dns_struct1, dns_struct2;
    dns_struct1.s_addr = dns1;
    dns_struct2.s_addr = dns2;
    property_set(mDns1Name,inet_ntoa(dns_struct1));
    property_set(mDns2Name,inet_ntoa(dns_struct2));
    return 0;
}


于 是我用无线路由器建立了一个最简单的无线网络,ssid=TSever,没有密码,按照上面步骤进行联网。结果在ADD_NETWORK的步骤就出错了, 无法获得网络id,这是怎么一回事呢?看到dhcp时的代码要对特定的Network Interface做操作,突然想起来之前在代码中似乎看到有对Interface做使能操作的代码——WifiService在调用 mWifiStateTracker.enableNetwork之前,还调用了String ifname = mWifiStateTracker.getInterfaceName(); NetworkUtils.enableInterface(ifname);这两句。于是在init阶段,加上了下面这段。

    char ifname[256];
    property_get("wifi.interface", ifname ,"eth0");
    ret = ifc_enable(ifname);
    if(ret < 0) {
        LOGE("Failed to enable wifi interface %s. %s", ifname ,strerror(errno));
        return -1;
    }

但 是运行起来还是出同样的错误,不过这次busybox ifconfig之后可以发现eth0的端口了 ,至少没有做无用功。倒回去看在WifiMonitor的MonitorThread中有connectToSupplicant()的调用,本以为此调 用不是非常关键,然后去hardware/libhardware_legacy/wifi/wifi.c文件里面看到全局有一个static struct wpa_ctrl *ctrl_conn;并且在wifi_command中需要用到这个ctrl_conn,那么如果这个ctrl_conn是NULL的话,所有的 wifi_command命令自然都无法完成了,于是又加上了

ret = wifi_connect_to_supplicant();
    if(ret < 0) {
        LOGE("Failed to connect supplicant daemon. %s",strerror(errno));
        return -1;
    }

这样编译完运行之后,果然顺利的分配到id了。运行一下程序,还是出现了错误,输出的log如下。

I/wpa_supplicant(  618): CTRL-EVENT-SCAN-RESULTS  Ready
I/wpa_supplicant(  618): Trying to associate with 00:24:b2:c1:16:b6 (SSID='TServer' freq=2462 MHz)
I/wpa_supplicant(  618): CTRL-EVENT-STATE-CHANGE id=-1 state=3
E/        (  612): Finished init stage.
E/        (  612): Add a network 2
E/        (  612): Finished config stage.
I/wpa_supplicant(  618): CTRL-EVENT-STATE-CHANGE id=1 state=0
E/        (  612): receive buf:
E/        (  612):  CTRL-EVENT-STATE-CHANGE id=1 state=0
I/wpa_supplicant(  618): CTRL-EVENT-STATE-CHANGE id=-1 state=2
E/        (  612): receive buf:
E/        (  612):  CTRL-EVENT-STATE-CHANGE id=-1 state=2
I/wpa_supplicant(  618): CTRL-EVENT-SCAN-RESULTS  Ready
E/        (  612): receive buf:
E/        (  612):  CTRL-EVENT-SCAN-RESULTS  Ready
I/wpa_supplicant(  618): CTRL-EVENT-STATE-CHANGE id=-1 state=4
E/        (  612): receive buf:
E/        (  612):  CTRL-EVENT-STATE-CHANGE id=-1 state=4
I/wpa_supplicant(  618): Associated with 00:24:b2:c1:16:b6
E/        (  612): receive buf:
E/        (  612):  Associated with 00:24:b2:c1:16:b6
I/wpa_supplicant(  618): CTRL-EVENT-SCAN-RESULTS  Ready
E/        (  612): receive buf:
E/        (  612):  CTRL-EVENT-SCAN-RESULTS  Ready
D/NetworkLocationProvider(  127): onCellLocationChanged [4517,30785]
I/wpa_supplicant(  618): Authentication with 00:24:b2:c1:16:b6 timed out.
E/        (  612): receive buf:
E/        (  612):  Authentication with 00:24:b2:c1:16:b6 timed out.

 
注意到红色的那句log,我的wifi并没有设置密码,为什么还需要Authentication呢?想一想是不是wpa_supplicant的限制,于是去网上搜了到了这篇wpa_supplicant 工具使用,发现没有密码的情况下应该是这样的配置
# 明文连接方式(不使用WPA和IEEE802.1X)
network={
  ssid="plaintext-test"
  key_mgmt=NONE
}
于是在config阶段加上了对key_mgmt的设置,这下就连上了Wifi了,正确的log如下

bash-4.1# wificonnect
I/wpa_supplicant(  871): CTRL-EVENT-SCAN-RESULTS  Ready
I/wpa_supplicant(  871): Trying to associate with 00:24:b2:c1:16:b6 (SSID='TServer' freq=2462 MHz)
I/wpa_supplicant(  871): CTRL-EVENT-STATE-CHANGE id=-1 state=3
E/        (  865): Finished init stage.
E/        (  865): Add a network 2
E/        (  865): Finished config stage.
I/wpa_supplicant(  871): CTRL-EVENT-STATE-CHANGE id=1 state=0
E/        (  865): receive buf:
E/        (  865):  CTRL-EVENT-STATE-CHANGE id=1 state=0
I/wpa_supplicant(  871): CTRL-EVENT-STATE-CHANGE id=-1 state=2
E/        (  865): receive buf:
E/        (  865):  CTRL-EVENT-STATE-CHANGE id=-1 state=2
I/wpa_supplicant(  871): CTRL-EVENT-SCAN-RESULTS  Ready
E/        (  865): receive buf:
E/        (  865):  CTRL-EVENT-SCAN-RESULTS  Ready
I/wpa_supplicant(  871): Trying to associate with 00:24:b2:c1:16:b6 (SSID='TServer' freq=2462 MHz)
E/        (  865): receive buf:
E/        (  865):  Trying to associate with 00:24:b2:c1:16:b6 (SSID='TServer' freq=2462 MHz)
I/wpa_supplicant(  871): CTRL-EVENT-STATE-CHANGE id=-1 state=3
E/        (  865): receive buf:
E/        (  865):  CTRL-EVENT-STATE-CHANGE id=-1 state=3
I/wpa_supplicant(  871): CTRL-EVENT-STATE-CHANGE id=2 state=4
E/        (  865): receive buf:
E/        (  865):  CTRL-EVENT-STATE-CHANGE id=2 state=4
I/wpa_supplicant(  871): Associated with 00:24:b2:c1:16:b6
I/wpa_supplicant(  871): CTRL-EVENT-STATE-CHANGE id=2 state=7
I/wpa_supplicant(  871): CTRL-EVENT-CONNECTED - Connection to 00:24:b2:c1:16:b6 completed (auth) [id=2 id_str=]
E/        (  865): receive buf:
E/        (  865):  Associated with 00:24:b2:c1:16:b6
E/        (  865): receive buf:
E/        (  865):  CTRL-EVENT-STATE-CHANGE id=2 state=7
E/        (  865): receive buf:
E/        (  865):  CTRL-EVENT-CONNECTED - Connection to 00:24:b2:c1:16:b6 completed (auth) [id=2 id_str=]
E/        (  865): Finished dhcp stage.

 
Android下实现非启动界面Wifi连接就算是完成了,以上工作是在界面启动并且Wifi设置关闭的情况下进行的,但和在没有界面的时候应该差别不大,下面是程序的源代码
/*  ** ** Copyright 2006, The Android Open Source Project ** ** Licensed under the Apache License, Version 2.0 (the "License"); ** you may not use this file except in compliance with the License. ** You may obtain a copy of the License at ** **      ** ** Unless required by applicable law or agreed to in writing, software ** distributed under the License is distributed on an "AS IS" BASIS, ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. ** See the License for the specific language governing permissions and ** limitations under the License. */ #include  #include  #include  #include  #include "string.h" #include "hardware_legacy/wifi.h" #include "cutils/log.h" #include "cutils/properties.h" #include  #include  #include  static int doCommand(const char *cmd, char *replybuf, int replybuflen) {     size_t reply_len = replybuflen - 1; 

    if (wifi_command(cmd, replybuf, &reply_len) != 0) 
        return -1; 
    else {         // Strip off trailing newline         if (reply_len > 0 && replybuf[reply_len-1] == '\n') 
            replybuf[reply_len-1] = '\0'; 
        else             replybuf[reply_len] = '\0'; 
        return 0; 
    } } static int doIntCommand(const char *cmd) {     char reply[256];     if (doCommand(cmd, reply, sizeof(reply)) != 0) {         return -1; 
    } else {         return atoi(reply); 
    } } static int doBooleanCommand(const char *cmd, const char *expect) {     char reply[256];     if (doCommand(cmd, reply, sizeof(reply)) != 0) {         return 0; 
    } else {         return (strcmp(reply, expect) == 0); 
    } } // Send a command to the supplicant, and return the reply as a String static char* doStringCommand(const char *cmd) {     char reply[4096];     if (doCommand(cmd, reply, sizeof(reply)) != 0) {         return NULL; 
    } else {         return reply; 
    } } int init_stage() {     // load the wifi driver: insmod .ko     int ret = wifi_load_driver(); 
    if(ret < 0) {         LOGE("Failed to load Wi-Fi driver. %s",strerror(errno)); 
        return -1; 
    }     // start wpa_supplicant     ret =  wifi_start_supplicant(); 
    if(ret < 0) {         LOGE("Failed to start supplicant daemon. %s",strerror(errno)); 
        return -1; 
    }     ret = wifi_connect_to_supplicant(); 
    if(ret < 0) {         LOGE("Failed to connect supplicant daemon. %s",strerror(errno)); 
        return -1; 
    }     char ifname[256];     property_get("wifi.interface", ifname ,"eth0"); 
    ret = ifc_enable(ifname); 
    if(ret < 0) {         LOGE("Failed to enable wifi interface %s. %s", ifname ,strerror(errno)); 
        return -1; 
    }     return 0; } int scan_stage(){     // XXX we don't need to really scan the wifi      return 0; } #define SSID_NAME "ssid" #define KEY_MGMT "key_mgmt" #define SSID "\"xxxxx\"" #define PASS "NONE" int config_stage(){    
    // Add a network config to supplicant mode     int networkId = doIntCommand("ADD_NETWORK"); // Add a new network id     if(networkId < 0) {         LOGE("Failed to add a network configuration. %s",strerror(errno)); 
        return -1; 
    }     LOGE("Add a network %d",networkId); 

    // set the ssid of the destination wifi adhoc     char cmdstr[256];     snprintf(cmdstr, sizeof(cmdstr), "SET_NETWORK %d %s %s",networkId, SSID_NAME, SSID); 
    if(!doBooleanCommand(cmdstr,"OK")) {         LOGE("Failed to set network %d configuration ssid. %s", networkId, strerror(errno)); 
        return -1; 
    } 
    snprintf(cmdstr, sizeof(cmdstr), "SET_NETWORK %d %s %s", networkId, KEY_MGMT ,PASS);
    if(!doBooleanCommand(cmdstr,"OK")) {
        LOGE("Failed to set network %d configuration key_mgmr. %s", networkId, strerror(errno));
        return -1;
    }


    return networkId;
}

#define CONNECTED "CONNECTED"
int connect_stage(int networkId) {
    char cmdstr[256];
    // enable the network
    snprintf(cmdstr, sizeof(cmdstr), "SELECT_NETWORK %d",networkId);
    if(!doBooleanCommand(cmdstr,"OK")) {
        LOGE("Failed to select network %d. %s", networkId, strerror(errno));
        return -1;
    }

    // wait for connect
    char buf[256];
    while(1) {
        int nread = wifi_wait_for_event(buf, sizeof(buf));
        if(nread > 0) {
            LOGE("receive buf:\n %s\n",buf);
            if(strstr(buf,CONNECTED) > 0) {
                break;
            }
            // XXX danger of not going out of the loop!!!
        }
        continue;
    }
    return 0;
}

int dhcp_stage(){
    int result;
    in_addr_t ipaddr, gateway, mask, dns1, dns2, server;
    uint32_t lease;

    char ifname[256];
    char mDns1Name[256];
    char mDns2Name[256];
    property_get("wifi.interface", ifname ,"eth0");
    snprintf(mDns1Name, sizeof(mDns1Name), "net.%s.dns1",ifname);
    snprintf(mDns2Name, sizeof(mDns2Name), "net.%s.dns2",ifname);

    result = dhcp_do_request(ifname, &ipaddr, &gateway, &mask, &dns1, &dns2, &server, &lease);
    if(result != 0) {
        LOGE("Failed to dhcp on interface %s. %s", ifname, strerror(errno));
        return -1;
    }
    struct in_addr dns_struct1, dns_struct2;
    dns_struct1.s_addr = dns1;
    dns_struct2.s_addr = dns2;
    property_set(mDns1Name,inet_ntoa(dns_struct1));
    property_set(mDns2Name,inet_ntoa(dns_struct2));
    return 0;
}

int main(int argc, char *argv[])
{
    int ret = init_stage();
    if(ret < 0) {
        LOGE("Failed init stage. %s",strerror(errno));
        exit(-1);
    }

    LOGE("Finished init stage.");

    ret = config_stage();
    if(ret < 0) {
        LOGE("Failed config stage. %s",strerror(errno));
        exit(-1);
    }
    LOGE("Finished config stage.");

    ret = connect_stage(ret);
    if(ret < 0) {
        LOGE("Failed connect stage. %s",strerror(errno));
        exit(-1);
    }
    LOGV("Finished connect stage.");

    ret = dhcp_stage();
    if(ret < 0) {
        LOGE("Failed dhcp stage. %s",strerror(errno));
        exit(-1);
    }
    LOGE("Finished dhcp stage.");
    return 0;
}

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