libs/android_runtime/android_net_wifi_Wifi.cpp

部分jni接口

static JNINativeMethod gWifiMethods[] = {

{ "loadDriver", "()Z", (void *)android_net_wifi_loadDriver },

{ "setPowerModeCommand", "(I)Z", (void*) android_net_wifi_setPowerModeCommand },//电源管理

{ "connectToSupplicant", "()Z", (void *)android_net_wifi_connectToSupplicant },

{ "waitForEvent", "()Ljava/lang/String;", (void*) android_net_wifi_waitForEvent },

{ "disconnectCommand", "()Z", (void *)android_net_wifi_disconnectCommand },

...

};

int register_android_net_wifi_WifiManager(JNIEnv* env)

{

...

return AndroidRuntime::registerNativeMethods(env,

WIFI_PKG_NAME, gWifiMethods, NELEM(gWifiMethods));//登记jni

}

libs/android_runtime/AndroidRuntime.cpp

static const RegJNIRec gRegJNI[] = {

...

REG_JNI(register_android_net_wifi_WifiManager),

...

};

int AndroidRuntime::startReg(JNIEnv* env)

{

...

register_jni_procs(gRegJNI, NELEM(gRegJNI), env);

...

}

AndroidRuntime::start

=>startReg(env)即调用方法int AndroidRuntime::startReg(JNIEnv* env)

=============================================================================================================

wifi_load_driver

wifi_start_supplicant

=>ensure_config_file_exists

//检查/data/misc/wifi/wpa_supplicant.conf文件是否存在,如果不存在,那么从/system/etc/wifi/wpa_supplicant.conf动态拷贝一份

android_net_wifi_connectToSupplicant

=>wifi_connect_to_supplicant

=>

ctrl_conn = wpa_ctrl_open(ifname);

monitor_conn = wpa_ctrl_open(ifname);

wpa_ctrl_attach(monitor_conn);

android_net_wifi_waitForEvent

=>wifi_wait_for_event

=>wpa_ctrl_recv(monitor_conn, buf, &nread);

=>recv(ctrl->s, reply, *reply_len, 0);//阻塞等待wpa_supplicant的netlink数据过来

=>如果接收的buf数据区,buf[0]为'<',那么说明有level级别信息,所以将'<'...'>'数据剔除,然后wifi_wait_for_event函数返回[luther.gliethttp].

java/android/android/net/wifi/WifiMonitor.java

public class WifiMonitor {

...

public void startMonitoring() {

new MonitorThread().start();//启动java线程

}

class MonitorThread extends Thread {

public MonitorThread() {

super("WifiMonitor");

}

public void run() {

for (;;) {

ensureSupplicantConnection();//=>WifiNative.connectToSupplicant调用jni函数android_net_wifi_connectToSupplicant

String eventStr = WifiNative.waitForEvent();//=>调用jni函数android_net_wifi_waitForEvent

//private static final int CONNECTED = 1;

//private static final int DISCONNECTED = 2;

//private static final String eventPrefix = "CTRL-EVENT-";

//private static final int eventPrefixLen = eventPrefix.length();

//private static final String connectedEvent = "CONNECTED";

//private static final String disconnectedEvent = "DISCONNECTED";

String eventName = eventStr.substring(eventPrefixLen);//去掉"CTRL-EVENT-"字符串

int nameEnd = eventName.indexOf(' ');//找到随后的空格位置,这在wpa_supplicant发送时

//#define WPA_EVENT_CONNECTED "CTRL-EVENT-CONNECTED "中,已经内置空格了.

if (nameEnd != -1)

eventName = eventName.substring(0, nameEnd);

int event;

if (eventName.equals(connectedEvent))//检测netlink过来的字符串action类型

event = CONNECTED;

else if (eventName.equals(disconnectedEvent))

event = DISCONNECTED;

...

int ind = eventStr.indexOf(" - ");//CTRL-EVENT-CONNECTED - Connection to ...

if (ind != -1)

eventData = eventStr.substring(ind + 3);

//剔除前导控制字符,将" - "后面的描述字符串作为真实数据,继续处理

...

if (event == STATE_CHANGE) {

handleSupplicantStateChange(eventData);

} else if (event == DRIVER_STATE) {

handleDriverEvent(eventData);

} else {

handleEvent(event, eventData);//对于CONNECTED和DISCONNECTED等netlink事件将执行此操作来处理[luther.gliethttp]

// If supplicant is gone, exit the thread

if (event == TERMINATING) {

break;

}

}

...

void handleEvent(int event, String remainder) {

switch (event) {

case DISCONNECTED:

handleNetworkStateChange(NetworkInfo.DetailedState.DISCONNECTED, remainder);

break;

case CONNECTED:

handleNetworkStateChange(NetworkInfo.DetailedState.CONNECTED, remainder);//控制界面显示

break;

...

}

public class WifiStateTracker extends NetworkStateTracker {

...

public void startEventLoop() {

mWifiMonitor.startMonitoring();//启动上面的MonitorThread线程

}

...

}

java/services/com/android/server/WifiService.java

public class WifiService extends IWifiManager.Stub {

...

private boolean setWifiEnabledBlocking(boolean enable) {

final int eventualWifiState = enable ? WIFI_STATE_ENABLED : WIFI_STATE_DISABLED;

...

if (enable) {

if (WifiNative.loadDriver()) {

Log.e(TAG, "Failed to load Wi-Fi driver.");

updateWifiState(WIFI_STATE_UNKNOWN);

return false;

}

if (WifiNative.startSupplicant()) {

WifiNative.unloadDriver();

Log.e(TAG, "Failed to start supplicant daemon.");

updateWifiState(WIFI_STATE_UNKNOWN);

return false;

}

mWifiStateTracker.startEventLoop();

//启动MonitorThread线程,等待wpa_supplicant将netlink数据转发过来,然后根据netlink动作类型,进一步影响界面显示[luther.gliethttp].

}

...

}

java/android/android/net/wifi/WifiStateTracker.java

电源管理

private void handleConnectedState() {

...

mDhcpTarget.obtainMessage(EVENT_DHCP_START).sendToTarget();//传递到下面的handleMessage方法

...

}

public void onChange(boolean selfChange) {

...

handleConnectedState();

...

}

public class WifiStateTracker extends NetworkStateTracker {

...

public void handleMessage(Message msg) {

switch (msg.what) {

case EVENT_SUPPLICANT_CONNECTION:

case EVENT_NETWORK_STATE_CHANGED:

handleConnectedState();//调用

...

private class DhcpHandler extends Handler {

private Handler mTarget;

public DhcpHandler(Looper looper, Handler target) {

super(looper);

mTarget = target;

}

public void handleMessage(Message msg) {

int event;

//private static final int DRIVER_POWER_MODE_AUTO = 0;

//private static final int DRIVER_POWER_MODE_ACTIVE = 1;

switch (msg.what) {

case EVENT_DHCP_START:

synchronized (this) {

WifiNative.setPowerModeCommand(DRIVER_POWER_MODE_ACTIVE);//设置电源模式,调用 android_net_wifi_setPowerModeCommand

}

Log.d(TAG, "DhcpHandler: DHCP request started");

//libs/android_runtime/android_net_NetUtils.cpp

//static JNINativeMethod gNetworkUtilMethods[] = {

//{ "runDhcp", "(Ljava/lang/String;Landroid/net/DhcpInfo;)Z", (void *)android_net_utils_runDhcp },

// ...

//};

if (NetworkUtils.runDhcp(mInterfaceName, mDhcpInfo)) {//执行dhcp申请ip地址操作

event = EVENT_INTERFACE_CONFIGURATION_SUCCEEDED;

if (LOCAL_LOGD) Log.v(TAG, "DhcpHandler: DHCP request succeeded");

} else {

event = EVENT_INTERFACE_CONFIGURATION_FAILED;

Log.i(TAG, "DhcpHandler: DHCP request failed: " +

NetworkUtils.getDhcpError());

//如果dhcpcd分配ip失败,那么Message.obtain(mTarget, event).sendToTarget();将执行

//WifiNative.disconnectCommand();即：static JNINativeMethod gWifiMethods[] = {

//android_net_wifi_disconnectCommand发送"DISCONNECT"字符串[luther.gliethttp]

//然后在wpa_supplicant服务端执行wpa_supplicant_ctrl_iface_process

//wpa_supplicant_disassociate

}

synchronized (this) {

WifiNative.setPowerModeCommand(DRIVER_POWER_MODE_AUTO);

}

Message.obtain(mTarget, event).sendToTarget();

break;

}

}

}

...

/**

* Send the tracker a notification that a connection to the supplicant

* daemon has been established.

*/

//在上面的public class WifiMonitor=>ensureSupplicantConnection

//=>

//while (!supplicantConnected) {

// boolean connected;

//synchronized (mWifiStateTracker) {

//connected = WifiNative.connectToSupplicant();//如果没有连接成功,那么while循环尝试,直到尝试成功,或者定义了oneShot,仅一次尝试

//=>mWifiStateTracker.notifySupplicantConnection();//如果WifiNative.connectToSupplicant()成功,那么将执行

//mWifiStateTracker.notifySupplicantConnection();的调用.

void notifySupplicantConnection() {//向对象发送message

Message.obtain(this, EVENT_SUPPLICANT_CONNECTION).sendToTarget();

}

void notifyStateChange(SupplicantState newState) {

Message.obtain(this, EVENT_SUPPLICANT_STATE_CHANGED, newState).sendToTarget();

}

...

}

static jboolean android_net_wifi_setPowerModeCommand(JNIEnv* env, jobject clazz, jint mode)

{

char cmdstr[256];

sprintf(cmdstr, "DRIVER POWERMODE %d", mode);

return doBooleanCommand(cmdstr, "OK");

}

android_net_wifi_setPowerModeCommand

=>doBooleanCommand

=>doCommand

=>wifi_command

=>wifi_send_command

=>wpa_ctrl_request

=>send给wpa_supplicant

然后wpa_supplicant将做如下接收操作：

system/extra/wpa_supplicant/main.c

=>wpa_supplicant_add_iface

=>wpa_supplicant_init_iface2

=>wpa_supplicant_ctrl_iface_init

=>注册ctrl_conn控制端口和monitor_conn监听端口的处理函数

eloop_register_read_sock(priv->sock, wpa_supplicant_ctrl_iface_receive, wpa_s, priv);//ctrl_conn端口的handler处理函数

wpa_msg_register_cb(wpa_supplicant_ctrl_iface_msg_cb);//monitor_conn端口的回调处理函数,处理netlink数据到所有monitor_conn监听端口

=>wpa_supplicant_ctrl_iface_receive//对于unix通信方式

=>wpa_supplicant_ctrl_iface_process

=>如果wpa_cli发送的是wpa_cli driver xxx形式的命令,那么调用这个函数

if (os_strncmp(buf, "DRIVER ", 7) == 0) {//掠过前7个,直接将命令传过去

reply_len = wpa_supplicant_driver_cmd(wpa_s, buf + 7, reply, reply_size);

=>wpa_supplicant_driver_cmd

=>wpa_drv_driver_cmd

=>自定义DRIVER扩展处理函数,所以对于java传递过来的power电源管理命令,wpa_drv_driver_cmd将收到"POWERMODE 0"或者"POWERMODE 1"字符串[luther.gliethttp]

=============================================================================================================

jni

=>runDhcp

=>android_net_utils_runDhcp

libs/netutils/dhcp_utils.c

=>dhcp_do_request

=>

static const char DAEMON_NAME[] = "dhcpcd";

static const char DAEMON_PROP_NAME[] = "init.svc.dhcpcd";

static const char DHCP_PROP_NAME_PREFIX[] = "dhcp";

const char *ctrl_prop = "ctl.start";

const char *desired_status = "running";

snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result",

DHCP_PROP_NAME_PREFIX,

interface);

property_set(result_prop_name, "");//设置dhcp.eth0.result="";等到成功完成dhcp之后,

property_set(ctrl_prop, DAEMON_NAME);//向名字为dhcpcd的service,发送"ctrl.start"启动命令字,该service在init.rc中

//init.rc中dhcpcd服务进程命令字

//service dhcpcd /system/bin/dhcpcd eth0

// disabled

// oneshot 

wait_for_property(DAEMON_PROP_NAME, desired_status, 10);

//init.c=>init进程

//=>handle_property_set_fd因为是"ctrl.start"命令字,所以调用handle_control_message处理控制信息

//=>handle_control_message

//=>msg_start

//=>

// struct service *svc = service_find_by_name(name);

// service_start(svc);//启动svc,即执行：/system/bin/dhcpcd eth0

//=>service_start

//=>pid = fork();

// if(pid == 0)execve(svc->args[0], (char**) svc->args, (char**) ENV);子进程执行execve运行/system/bin/dhcpcd,参数为eth0

//=>否则父进程,即init进程将

//=>notify_service_state(svc->name, "running");设置该svc的状态prop

// snprintf(pname, sizeof(pname), "init.svc.%s", name);

// property_set(pname, state);//所以这样上面wait_for_property(DAEMON_PROP_NAME, desired_status, 10);也才能够正常pass[luther.gliethttp].

wait_for_property(result_prop_name, NULL, 15);//等待dhcp.eth0.result=非空

=============================================================================================================

system/extra/dhcpcd-4.0.0-beta9/dhcpcd.c

dhcpcd

=>main

# define SYSCONFDIR "/system/etc/dhcpcd"

#define PACKAGE "dhcpcd"

# define CONFIG SYSCONFDIR "/" PACKAGE ".conf"

# define LIBEXECDIR "/system/etc/dhcpcd"

# define SCRIPT LIBEXECDIR "/" PACKAGE "-run-hooks"

=>strlcpy(options->script, SCRIPT, sizeof(options->script));//默认的options->script="/system/etc/dhcpcd /dhcpcd-run-hooks"

=>f = fopen(cf ? cf : CONFIG, "r");//如果没有指定.conf文件,那么使用默认.conf文件

=>parse_config_line//解析"/system/etc/dhcpcd/dhcpcd.conf"默认配置文件

=>parse_option

=>如果在"/system/etc/dhcpcd/dhcpcd.conf"有"script"这个节

=>那么执行strlcpy(options->script, oarg, sizeof(options->script));直接拷贝

/*

{"script", required_argument, NULL, 'c'},

{"option", required_argument, NULL, 'o'},

"/system/etc/dhcpcd/dhcpcd.conf"中的部分内容如下：

...

option domain_name_servers, domain_name, domain_search, host_name

...

*/

=>dhcp_run

=>handle_dhcp_packet

=>handle_dhcp

=>bind_dhcp

reason = "TIMEOUT";reason = "BOUND";reason = "REBIND";reason = "RENEW";

system/extra/dhcpcd-4.0.0-beta9/configure.c

=> configure(iface, reason, state->new, state->old, &state->lease, options, 1);

//如果dhcp超时或者dhcp成功,都会调用exec_script来执行脚本,

//执行setprop dhcp.${interface}.result "failed"或者

//执行setprop dhcp.${interface}.result "ok"

=>exec_script(options, iface->name, reason, NULL, old);

=>然后configure_env通过环境变量将reason传递到脚本中

int exec_script(const struct options *options, const char *iface, const char *reason,

const struct dhcp_message *dhcpn, const struct dhcp_message *dhcpo)

=>pid = fork();

=>if(pid == 0)execve(options->script, argv, env);//子进程执行脚本,默认"/system/etc/dhcpcd/dhcpcd-run-hooks"

//dhcpcd-run-hooks脚本会根据level值,决定是否执行system/etc/dhcpcd/dhcpcd-hook/*目录下的相应文件

//我们的系统在该system/etc/dhcpcd/dhcpcd-hook/*目录下有如下3个文件

//95-configured

//20-dns.conf

//01-test

=>父进程返回while (waitpid(pid, &status, 0) == -1)等待子进程脚本执行完成

system/extra/dhcpcd-4.0.0-beta9/dhcpcd-hooks/20-dns.conf

system/extra/dhcpcd-4.0.0-beta9/dhcpcd-hooks/95-configured

...

setprop dhcp.${interface}.ipaddress "${new_ip_address}"

setprop dhcp.${interface}.result "ok"//设置属性为ok

setprop dhcp.${interface}.result "failed"

...

=============================================================================================================

inet_init、tcp_prot

sock->ops->sendmsg(iocb, sock, msg, size);

=>inetsw_array[]

=>inet_stream_ops

=>tcp_sendmsg

=============================================================================================================

wpa_cli.c

=>main

=>wpa_cli_interactive

=>wpa_cli_recv_pending(monitor_conn, 0, 0);//阻塞等待wpa_supplicant发送数据过来

=>如果action_monitor为true,那么将执行一些简单加工操作,否则将直接将wpa_supplicant发过来的数据打印到console上[luther.gliethttp].

原地址：http://www.wangchao.net.cn/it/detail_60528.html