Android移植_wifi设计原理(源码分析)

android-4.0.1源码分析wifi篇1) 在分析4.0 的代码前，我们先看⼀下 2.3.1 的wifi相关的代码结构①⾸先进⼊到 android-2.3_r1/frameworks/base/wifi ⽬录下.`-- java`-- android`-- net`-- wifi|-- IWifiManager.aidl|-- package.html|-- ScanResult.aidl|-- ScanResult.java|-- SupplicantState.java|-- WifiConfiguration.aidl|-- WifiConfiguration.java|-- WifiInfo.aidl|-- WifiInfo.java|-- WifiManager.java|-- WifiMonitor.java|-- WifiNative.java`-- WifiStateTracker.java4 directories, 13 files我们可以看到有13个⽂件,其中有 4 个 aidl , 1 个 html ⽂件, 8 个 java ⽂件. 除了 IWifiManager.aidl ⽂件外，其余3个 aidl ⽂件都只有⼀句话，那就是串⾏化这个 aidl.在 IWifiManager.aidl⽂件中/*** Copyright (c) 2008, 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.*/package .wifi;import .wifi.WifiInfo;import .wifi.WifiConfiguration;import .wifi.ScanResult;import .DhcpInfo;import android.os.WorkSource;/*** Interface that allows controlling and querying Wi-Fi connectivity.** }*/interface IWifiManager{List<WifiConfiguration> getConfiguredNetworks();int addOrUpdateNetwork(in WifiConfiguration config);boolean removeNetwork(int netId);boolean enableNetwork(int netId, boolean disableOthers);boolean disableNetwork(int netId);boolean pingSupplicant();void startScan(boolean forceActive);List<ScanResult> getScanResults();boolean disconnect();boolean reconnect();boolean reassociate();WifiInfo getConnectionInfo();boolean setWifiEnabled(boolean enable);int getWifiEnabledState();int getNumAllowedChannels();boolean setNumAllowedChannels(int numChannels, boolean persist);int[] getValidChannelCounts();boolean saveConfiguration();DhcpInfo getDhcpInfo();boolean acquireWifiLock(IBinder lock, int lockType, String tag, in WorkSource ws);void updateWifiLockWorkSource(IBinder lock, in WorkSource ws);boolean releaseWifiLock(IBinder lock);void initializeMulticastFiltering();boolean isMulticastEnabled();void acquireMulticastLock(IBinder binder, String tag);void releaseMulticastLock();boolean setWifiApEnabled(in WifiConfiguration wifiConfig, boolean enable);int getWifiApEnabledState();WifiConfiguration getWifiApConfiguration();void setWifiApConfiguration(in WifiConfiguration wifiConfig);}我们可以看到，上⾯的 aidl 主要是与通迅相关的内容，这层肯定与硬件相关，java 代码是⽆法直接和硬件联系的，所以只好放⼊到 aidl ⽂件中.下⾯，我们可以看下其他的 java ⽂件.我们先看⼀下 SupplicantState.java 这个 java ⽂件.package .wifi;import android.os.Parcel;import android.os.Parcelable;public enum SupplicantState implements Parcelable {DISCONNECTED,INACTIVE,SCANNING,ASSOCIATING,ASSOCIATED,FOUR_WAY_HANDSHAKE,GROUP_HANDSHAKE,OMPLETED,DORMANT,UNINITIALIZED,INVALID;/*** Returns true} if the supplicant state is valid and false}* otherwise.* @param state The supplicant state* @return true} if the supplicant state is valid and false}* otherwise.*/public static boolean isValidState(SupplicantState state) {return state != UNINITIALIZED && state != INVALID;}/** Implement the Parcelable interface } */public int describeContents() {return 0;}/** Implement the Parcelable interface } */public void writeToParcel(Parcel dest, int flags) {dest.writeString(name());}/** Implement the Parcelable interface } */public static final Creator<SupplicantState> CREATOR =new Creator<SupplicantState>() {public SupplicantState createFromParcel(Parcel in) {return SupplicantState.valueOf(in.readString());}public SupplicantState[] newArray(int size) {return new SupplicantState[size];}};}以上代码主要是取得 wpa_supplicant的状态及其状态定义相关的代码.下⾯我们来看看 ScanResult.java 的代码package .wifi;import android.os.Parcelable;import android.os.Parcel;public class ScanResult implements Parcelable {/** The network name. */public String SSID;/** The address of the access point. */public String BSSID;/*** Describes the authentication, key management, and encryption schemes * supported by the access point.*/public String capabilities;/*** The detected signal level in dBm. At least those are the units used by* the TI driver.*/public int level;/*** The frequency in MHz of the channel over which the client is communicating* with the access point.*/public int frequency;/*** We'd like to obtain the following attributes,* but they are not reported via the socket* interface, even though they are known* internally by wpa_supplicant.* }*/public ScanResult(String SSID, String BSSID, String caps, int level, int frequency) { this.SSID = SSID;this.BSSID = BSSID;this.capabilities = caps;this.level = level;this.frequency = frequency;//networkConfig = null;}@Overridepublic String toString() {StringBuffer sb = new StringBuffer();String none = "<none>";sb.append("SSID: ").append(SSID == null ? none : SSID).append(", BSSID: ").append(BSSID == null ? none : BSSID).append(", capabilities: ").append(capabilities == null ? none : capabilities).append(", level: ").append(level).append(", frequency: ").append(frequency);return sb.toString();}/** Implement the Parcelable interface } */public int describeContents() {return 0;}/** Implement the Parcelable interface } */public void writeToParcel(Parcel dest, int flags) {dest.writeString(SSID);dest.writeString(BSSID);dest.writeString(capabilities);dest.writeInt(level);dest.writeInt(frequency);}/** Implement the Parcelable interface } */public static final Creator<ScanResult> CREATOR =new Creator<ScanResult>() {public ScanResult createFromParcel(Parcel in) {return new ScanResult(in.readString(),in.readString(),in.readString(),in.readInt(),in.readInt());}public ScanResult[] newArray(int size) {return new ScanResult[size];}};}上⾯的代码主要是对搜索结果的处理.接下来,我们来看⼀下 WifiInfo.java ⽂件package .wifi;import android.os.Parcelable;import android.os.Parcel;import workInfo.DetailedState;import java.util.EnumMap;/*** Describes the state of any Wifi connection that is active or* is in the process of being set up.*/public class WifiInfo implements Parcelable {/*** This is the map described in the Javadoc comment above. The positions* of the elements of the array must correspond to the ordinal values* of <code>DetailedState</code>.*/private static final EnumMap<SupplicantState, DetailedState> stateMap =new EnumMap<SupplicantState, DetailedState>(SupplicantState.class);static {stateMap.put(SupplicantState.DISCONNECTED, DetailedState.DISCONNECTED);stateMap.put(SupplicantState.INACTIVE, DetailedState.IDLE);stateMap.put(SupplicantState.SCANNING, DetailedState.SCANNING);stateMap.put(SupplicantState.ASSOCIATING, DetailedState.CONNECTING);stateMap.put(SupplicantState.ASSOCIATED, DetailedState.CONNECTING);stateMap.put(SupplicantState.FOUR_WAY_HANDSHAKE, DetailedState.AUTHENTICATING); stateMap.put(SupplicantState.GROUP_HANDSHAKE, DetailedState.AUTHENTICATING);stateMap.put(PLETED, DetailedState.OBTAINING_IPADDR);stateMap.put(SupplicantState.DORMANT, DetailedState.DISCONNECTED);stateMap.put(SupplicantState.UNINITIALIZED, DetailedState.IDLE);stateMap.put(SupplicantState.INVALID, DetailedState.FAILED);}private SupplicantState mSupplicantState;private String mBSSID;private String mSSID;private int mNetworkId;private boolean mHiddenSSID;/** Received Signal Strength Indicator */private int mRssi;/** Link speed in Mbps */public static final String LINK_SPEED_UNITS = "Mbps";private int mLinkSpeed;private int mIpAddress;private String mMacAddress;WifiInfo() {mSSID = null;mBSSID = null;mNetworkId = -1;mSupplicantState = SupplicantState.UNINITIALIZED;mRssi = -9999;mLinkSpeed = -1;mIpAddress = 0;mHiddenSSID = false;}void setSSID(String SSID) {mSSID = SSID;// network is considered not hidden by defaultmHiddenSSID = false;}/*** Returns the service set identifier (SSID) of the current 802.11 network.* If the SSID is an ASCII string, it will be returned surrounded by double* quotation marks.Otherwise, it is returned as a string of hex digits. The* SSID may be null} if there is no network currently connected.* @return the SSID*/public String getSSID() {return mSSID;}void setBSSID(String BSSID) {mBSSID = BSSID;}/*** Return the basic service set identifier (BSSID) of the current access point.* The BSSID may be null} if there is no network currently connected.* @return the BSSID, in the form of a six-byte MAC address: XX:XX:XX:XX:XX:XX} */public String getBSSID() {return mBSSID;}/*** Returns the received signal strength indicator of the current 802.11* network.* <p><strong>This is not normalized, but should be!</strong></p>* @return the RSSI, in the range to*/public int getRssi() {return mRssi;}void setRssi(int rssi) {mRssi = rssi;}/*** Returns the current link speed in #LINK_SPEED_UNITS}.* @return the link speed.* @see #LINK_SPEED_UNITS*/public int getLinkSpeed() {return mLinkSpeed;}void setLinkSpeed(int linkSpeed) {this.mLinkSpeed = linkSpeed;}/*** Record the MAC address of the WLAN interface* @param macAddress the MAC address in XX:XX:XX:XX:XX:XX} form*/void setMacAddress(String macAddress) {this.mMacAddress = macAddress;}public String getMacAddress() {return mMacAddress;}void setNetworkId(int id) {mNetworkId = id;}/*** Each configured network has a unique small integer ID, used to identify* the network when performing operations on the supplicant. This method* returns the ID for the currently connected network.* @return the network ID, or -1 if there is no currently connected network*/public int getNetworkId() {return mNetworkId;}/*** Return the detailed state of the supplicant's negotiation with an* access point, in the form of a SupplicantState SupplicantState} object.* @return the current SupplicantState SupplicantState}*/public SupplicantState getSupplicantState() {return mSupplicantState;}void setSupplicantState(SupplicantState state) {mSupplicantState = state;}void setIpAddress(int address) {mIpAddress = address;}public int getIpAddress() {return mIpAddress;}/*** @return true} if this network does not broadcast its SSID, so an* SSID-specific probe request must be used for scans.*/public boolean getHiddenSSID() {return mHiddenSSID;}/** } */public void setHiddenSSID(boolean hiddenSSID) {mHiddenSSID = hiddenSSID;}/*** Map a supplicant state into a fine-grained network connectivity state.* @param suppState the supplicant state* @return the corresponding DetailedState}*/public static DetailedState getDetailedStateOf(SupplicantState suppState) {return stateMap.get(suppState);}/*** Set the <code>SupplicantState</code> from the string name* of the state.* @param stateName the name of the state, as a <code>String</code> returned * in an event sent by wpa_supplicant}.*/void setSupplicantState(String stateName) {mSupplicantState = valueOf(stateName);}static SupplicantState valueOf(String stateName) {if ("4WAY_HANDSHAKE".equalsIgnoreCase(stateName))return SupplicantState.FOUR_WAY_HANDSHAKE;else {try {return SupplicantState.valueOf(stateName.toUpperCase());} catch (IllegalArgumentException e) {return SupplicantState.INVALID;}}}@Overridepublic String toString() {StringBuffer sb = new StringBuffer();String none = "<none>";sb.append("SSID: ").append(mSSID == null ? none : mSSID).append(", BSSID: ").append(mBSSID == null ? none : mBSSID).append(", MAC: ").append(mMacAddress == null ? none : mMacAddress).append(", Supplicant state: ").append(mSupplicantState == null ? none : mSupplicantState).append(", RSSI: ").append(mRssi).append(", Link speed: ").append(mLinkSpeed).append(", Net ID: ").append(mNetworkId);return sb.toString();}/** Implement the Parcelable interface } */public int describeContents() {return 0;}/** Implement the Parcelable interface } */public void writeToParcel(Parcel dest, int flags) {dest.writeInt(mNetworkId);dest.writeInt(mRssi);dest.writeInt(mLinkSpeed);dest.writeInt(mIpAddress);dest.writeString(getSSID());dest.writeString(mBSSID);dest.writeString(mMacAddress);mSupplicantState.writeToParcel(dest, flags);}/** Implement the Parcelable interface } */public static final Creator<WifiInfo> CREATOR =new Creator<WifiInfo>() {public WifiInfo createFromParcel(Parcel in) {WifiInfo info = new WifiInfo();info.setNetworkId(in.readInt());info.setRssi(in.readInt());info.setLinkSpeed(in.readInt());info.setIpAddress(in.readInt());info.setSSID(in.readString());info.mBSSID = in.readString();info.mMacAddress = in.readString();info.mSupplicantState = SupplicantState.CREATOR.createFromParcel(in); return info;}public WifiInfo[] newArray(int size) {return new WifiInfo[size];}};}接下来,我们来看⼀下 WifiMonitor.java 这个⽂件.②③④⑤⑥⑦⑧⑨⑩云计算开发平台①　WSO2的应⽤服务器②　③　④环境搭建。

androidwifiralinkrt3070开发记录原文地址/robinyeung/article/details/7265640一、wifi基本架构1、开源代码移植部分（external目录下）wireless_tools、wpa_supplicant、wpa_supplicant_6(后两项已经移植过)生成库libwpaclient.so和守护进程wpa_supplicant及iwconfig、iwlist等相关的测试程序2、hardware/libhardware_legary/wifi/wifi.c是wifi管理库生成libnetutils.so同时会和wpa_supplicant守护进程通信3、JNI部分frameworks/base/core/jni/android_net_wifi_Wifi.cpp 这个是无线connect、scan方面的调用frameworks/base/core/jni/android_net_NetUtils.cpp 这个是管理网络方面的工具，如dhcp、route、net en/unable等4、JAVA部分frameworks/base/services/java/com/android/server/frameworks/base/wifi/java/android/net/wifi/frameworks/base/core/java/android/net 这个是管理网络的工具，调用第三条的第二个jni5、WIFI Settings位于packages/apps/Settings/src/com/android/settings/wifi/6、WIFI驱动模块rt5370sta.ko(此驱动兼容使用ralink的好多种设备驱动，具体可以查看USB_DEVICE_ID)wpa_supplicant通过wireless_ext 接口和驱动通信7、WIFI 硬件模块D-Link DWA-125 芯片：ralink RT3070二、wifi开发记录1、5370驱动编译安装及使用过程set the "MODE = STA" in Makefile and chose the TARGET to Linux by set "TARGET = LINUX"set 'HAS_WPA_SUPPLICANT=y' and 'HAS_NATIVE_WPA_SUPPLICANT_SUPPORT=y'#wpa_supplicant -Dwext -iwlan0 -c wpa_supplicant.conf -d （-c这里需要指定下wpa_supplicant.conf的路径）wpa_supplicant.conf 内容：ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=wheel network={ssid="home"scan_ssid=1key_mgmt=WPA-PSKpsk="very secret passphrase"} // 这个地方的大括号中的内容可在settings中点击选择某个ap 后自动生成#sudo su （android平台需要自己添加脚本编译，和这里写的有差异）#make clean#make#make install#modprobe rt5370sta#ifconfig wlan0 up#iwconfig wlan0#iwlist wlan0 scan 这时候已经可以扫描wi-fi网络了下面是dhcpcd wlan0即可。

二：Wifi模块的初始化:：在 SystemServer 启动的时候，会生成一个ConnectivityService 的实例，try {Log.i(TAG, "Starting Connectivity Service.");ServiceManager.addService(Context.CONNECTIVITY_SERVICE, newConnectivityService(context));} catch (Throwable e) {Log.e(TAG, "Failure starting Connectivity Service", e);}ConnectivityService 的构造函数会创建WifiService，if (DBG) Log.v(TAG, "Starting Wifi Service.");mWifiStateTracker = new WifiStateTracker(context, handler);WifiService wifiService = new WifiService(context, mWifiStateTracker); ServiceManager.addService(Context.WIFI_SERVICE, wifiService);WifiStateTracker 会创建WifiMonitor 接收来自底层的事件，WifiService 和WifiMonitor 是整个模块的核心。

WifiService 负责启动关闭wpa_supplicant、启动关闭WifiMonitor 监视线程和把命令下发给wpa_supplicant，而WifiMonitor 则负责从wpa_supplicant 接收事件通知。

具体流程图如下：第三部分：Wifi模块的启动（使能）WirelessSettings 在初始化的时候配置了由WifiEnabler 来处理Wifi 按钮，private void initToggles() {mWifiEnabler = new WifiEnabler(this,(WifiManager) getSystemService(WIFI_SERVICE),(CheckBoxPreference) findPreference(KEY_TOGGLE_WIFI));当用户按下Wifi 按钮后，Android 会调用WifiEnabler 的onPreferenceChange，再由WifiEnabler 调用WifiManager 的setWifiEnabled 接口函数，通过AIDL，实际调用的是WifiService 的setWifiEnabled 函数，WifiService 接着向自身发送一条MESSAGE_ENABLE_WIFI 消息，在处理该消息的代码中做真正的使能工作：首先装载WIFI 内核模块（该模块的位置硬编码为"/system/lib/modules/wlan.ko" ），然后启动wpa_supplicant （配置文件硬编码为"/data/misc/wifi/wpa_supplicant.conf"），再通过WifiStateTracker 来启动WifiMonitor 中的监视线程。

Contents1. Wifi扫盲 (2)2. Android Wifi框架的结构图 (3)3. wpa_supplient (3)4. Netd (5)5. FrameWork层架构 (5)6. 情景分析 (5)6.1. 情景1 (5)6.2. 情景2 (8)6.3. 情景3 (8)7.Ad hoc的支持 (10)8.wifi direct (12)9.Soft ap支持 (12)10.Wifi Tethering支持 (15)b Tethering支持 (15)12.Reverse usb Tethering (16)13.Ethernet Tethering (17)14.需要改动的地方 (17)15.测试 (17)16.调试中遇到的问题 (18)1. Wifi扫盲Access point：也叫hotspot(热点)，家里的无线路由就是ap。

SoftAp：软ap，用无线网卡模拟ap的功能。

Wifi网络有两种模式：∙Infrastructure mode, in which wireless clients are connected to an access point. This is generally the default mode for 802.11b cards.∙Ad hoc mode, in which clients are connected to one another without any access point.请参考/contents/wifi/wifimodes.php3我们既可以通过Ad hoc也可以通过SoftAp方式来实现共享网络(例如手机可以通过笔记本访问internet)，但是原理不同。

这里只是简单的概括，详细的解释请google或百度。

2. Android Wifi框架的结构图上图只是wifi工作于station模式时的图，当工作于soft ap模式时最基本的不同是不通过wpa_supplicant而是Framework层直接通过netd daemon来控制驱动。