1 /* 2 * Copyright (C) 2014 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package android.net; 18 19 import android.net.NetworkUtils; 20 import android.os.Parcelable; 21 import android.os.Parcel; 22 import android.system.ErrnoException; 23 24 import java.io.IOException; 25 import java.net.InetAddress; 26 import java.net.InetSocketAddress; 27 import java.net.MalformedURLException; 28 import java.net.Socket; 29 import java.net.SocketAddress; 30 import java.net.SocketException; 31 import java.net.UnknownHostException; 32 import java.net.URL; 33 import java.net.URLConnection; 34 import java.net.URLStreamHandler; 35 import java.util.concurrent.atomic.AtomicReference; 36 import javax.net.SocketFactory; 37 38 import com.android.okhttp.ConnectionPool; 39 import com.android.okhttp.HostResolver; 40 import com.android.okhttp.HttpHandler; 41 import com.android.okhttp.HttpsHandler; 42 import com.android.okhttp.OkHttpClient; 43 44 /** 45 * Identifies a {@code Network}. This is supplied to applications via 46 * {@link ConnectivityManager.NetworkCallback} in response to the active 47 * {@link ConnectivityManager#requestNetwork} or passive 48 * {@link ConnectivityManager#registerNetworkCallback} calls. 49 * It is used to direct traffic to the given {@code Network}, either on a {@link Socket} basis 50 * through a targeted {@link SocketFactory} or process-wide via 51 * {@link ConnectivityManager#setProcessDefaultNetwork}. 52 */ 53 public class Network implements Parcelable { 54 55 /** 56 * @hide 57 */ 58 public final int netId; 59 60 // Objects used to perform per-network operations such as getSocketFactory 61 // and openConnection, and a lock to protect access to them. 62 private volatile NetworkBoundSocketFactory mNetworkBoundSocketFactory = null; 63 // mLock should be used to control write access to mConnectionPool and mHostResolver. 64 // maybeInitHttpClient() must be called prior to reading either variable. 65 private volatile ConnectionPool mConnectionPool = null; 66 private volatile HostResolver mHostResolver = null; 67 private Object mLock = new Object(); 68 69 // Default connection pool values. These are evaluated at startup, just 70 // like the OkHttp code. Also like the OkHttp code, we will throw parse 71 // exceptions at class loading time if the properties are set but are not 72 // valid integers. 73 private static final boolean httpKeepAlive = 74 Boolean.parseBoolean(System.getProperty("http.keepAlive", "true")); 75 private static final int httpMaxConnections = 76 httpKeepAlive ? Integer.parseInt(System.getProperty("http.maxConnections", "5")) : 0; 77 private static final long httpKeepAliveDurationMs = 78 Long.parseLong(System.getProperty("http.keepAliveDuration", "300000")); // 5 minutes. 79 80 /** 81 * @hide 82 */ 83 public Network(int netId) { 84 this.netId = netId; 85 } 86 87 /** 88 * @hide 89 */ 90 public Network(Network that) { 91 this.netId = that.netId; 92 } 93 94 /** 95 * Operates the same as {@code InetAddress.getAllByName} except that host 96 * resolution is done on this network. 97 * 98 * @param host the hostname or literal IP string to be resolved. 99 * @return the array of addresses associated with the specified host. 100 * @throws UnknownHostException if the address lookup fails. 101 */ 102 public InetAddress[] getAllByName(String host) throws UnknownHostException { 103 return InetAddress.getAllByNameOnNet(host, netId); 104 } 105 106 /** 107 * Operates the same as {@code InetAddress.getByName} except that host 108 * resolution is done on this network. 109 * 110 * @param host 111 * the hostName to be resolved to an address or {@code null}. 112 * @return the {@code InetAddress} instance representing the host. 113 * @throws UnknownHostException 114 * if the address lookup fails. 115 */ 116 public InetAddress getByName(String host) throws UnknownHostException { 117 return InetAddress.getByNameOnNet(host, netId); 118 } 119 120 /** 121 * A {@code SocketFactory} that produces {@code Socket}'s bound to this network. 122 */ 123 private class NetworkBoundSocketFactory extends SocketFactory { 124 private final int mNetId; 125 126 public NetworkBoundSocketFactory(int netId) { 127 super(); 128 mNetId = netId; 129 } 130 131 private Socket connectToHost(String host, int port, SocketAddress localAddress) 132 throws IOException { 133 // Lookup addresses only on this Network. 134 InetAddress[] hostAddresses = getAllByName(host); 135 // Try all addresses. 136 for (int i = 0; i < hostAddresses.length; i++) { 137 try { 138 Socket socket = createSocket(); 139 if (localAddress != null) socket.bind(localAddress); 140 socket.connect(new InetSocketAddress(hostAddresses[i], port)); 141 return socket; 142 } catch (IOException e) { 143 if (i == (hostAddresses.length - 1)) throw e; 144 } 145 } 146 throw new UnknownHostException(host); 147 } 148 149 @Override 150 public Socket createSocket(String host, int port, InetAddress localHost, int localPort) throws IOException { 151 return connectToHost(host, port, new InetSocketAddress(localHost, localPort)); 152 } 153 154 @Override 155 public Socket createSocket(InetAddress address, int port, InetAddress localAddress, 156 int localPort) throws IOException { 157 Socket socket = createSocket(); 158 socket.bind(new InetSocketAddress(localAddress, localPort)); 159 socket.connect(new InetSocketAddress(address, port)); 160 return socket; 161 } 162 163 @Override 164 public Socket createSocket(InetAddress host, int port) throws IOException { 165 Socket socket = createSocket(); 166 socket.connect(new InetSocketAddress(host, port)); 167 return socket; 168 } 169 170 @Override 171 public Socket createSocket(String host, int port) throws IOException { 172 return connectToHost(host, port, null); 173 } 174 175 @Override 176 public Socket createSocket() throws IOException { 177 Socket socket = new Socket(); 178 bindSocket(socket); 179 return socket; 180 } 181 } 182 183 /** 184 * Returns a {@link SocketFactory} bound to this network. Any {@link Socket} created by 185 * this factory will have its traffic sent over this {@code Network}. Note that if this 186 * {@code Network} ever disconnects, this factory and any {@link Socket} it produced in the 187 * past or future will cease to work. 188 * 189 * @return a {@link SocketFactory} which produces {@link Socket} instances bound to this 190 * {@code Network}. 191 */ 192 public SocketFactory getSocketFactory() { 193 if (mNetworkBoundSocketFactory == null) { 194 synchronized (mLock) { 195 if (mNetworkBoundSocketFactory == null) { 196 mNetworkBoundSocketFactory = new NetworkBoundSocketFactory(netId); 197 } 198 } 199 } 200 return mNetworkBoundSocketFactory; 201 } 202 203 // TODO: This creates a connection pool and host resolver for 204 // every Network object, instead of one for every NetId. This is 205 // suboptimal, because an app could potentially have more than one 206 // Network object for the same NetId, causing increased memory footprint 207 // and performance penalties due to lack of connection reuse (connection 208 // setup time, congestion window growth time, etc.). 209 // 210 // Instead, investigate only having one connection pool and host resolver 211 // for every NetId, perhaps by using a static HashMap of NetIds to 212 // connection pools and host resolvers. The tricky part is deciding when 213 // to remove a map entry; a WeakHashMap shouldn't be used because whether 214 // a Network is referenced doesn't correlate with whether a new Network 215 // will be instantiated in the near future with the same NetID. A good 216 // solution would involve purging empty (or when all connections are timed 217 // out) ConnectionPools. 218 private void maybeInitHttpClient() { 219 synchronized (mLock) { 220 if (mHostResolver == null) { 221 mHostResolver = new HostResolver() { 222 @Override 223 public InetAddress[] getAllByName(String host) throws UnknownHostException { 224 return Network.this.getAllByName(host); 225 } 226 }; 227 } 228 if (mConnectionPool == null) { 229 mConnectionPool = new ConnectionPool(httpMaxConnections, 230 httpKeepAliveDurationMs); 231 } 232 } 233 } 234 235 /** 236 * Opens the specified {@link URL} on this {@code Network}, such that all traffic will be sent 237 * on this Network. The URL protocol must be {@code HTTP} or {@code HTTPS}. 238 * 239 * @return a {@code URLConnection} to the resource referred to by this URL. 240 * @throws MalformedURLException if the URL protocol is not HTTP or HTTPS. 241 * @throws IOException if an error occurs while opening the connection. 242 * @see java.net.URL#openConnection() 243 */ 244 public URLConnection openConnection(URL url) throws IOException { 245 maybeInitHttpClient(); 246 String protocol = url.getProtocol(); 247 OkHttpClient client; 248 // TODO: HttpHandler creates OkHttpClients that share the default ResponseCache. 249 // Could this cause unexpected behavior? 250 // TODO: Should the network's proxy be specified? 251 if (protocol.equals("http")) { 252 client = HttpHandler.createHttpOkHttpClient(null /* proxy */); 253 } else if (protocol.equals("https")) { 254 client = HttpsHandler.createHttpsOkHttpClient(null /* proxy */); 255 } else { 256 // OkHttpClient only supports HTTP and HTTPS and returns a null URLStreamHandler if 257 // passed another protocol. 258 throw new MalformedURLException("Invalid URL or unrecognized protocol " + protocol); 259 } 260 return client.setSocketFactory(getSocketFactory()) 261 .setHostResolver(mHostResolver) 262 .setConnectionPool(mConnectionPool) 263 .open(url); 264 } 265 266 /** 267 * Binds the specified {@link Socket} to this {@code Network}. All data traffic on the socket 268 * will be sent on this {@code Network}, irrespective of any process-wide network binding set by 269 * {@link ConnectivityManager#setProcessDefaultNetwork}. The socket must not be connected. 270 */ 271 public void bindSocket(Socket socket) throws IOException { 272 if (socket.isConnected()) { 273 throw new SocketException("Socket is connected"); 274 } 275 // Query a property of the underlying socket to ensure the underlying 276 // socket exists so a file descriptor is available to bind to a network. 277 socket.getReuseAddress(); 278 int err = NetworkUtils.bindSocketToNetwork(socket.getFileDescriptor$().getInt$(), netId); 279 if (err != 0) { 280 // bindSocketToNetwork returns negative errno. 281 throw new ErrnoException("Binding socket to network " + netId, -err) 282 .rethrowAsSocketException(); 283 } 284 } 285 286 // implement the Parcelable interface 287 public int describeContents() { 288 return 0; 289 } 290 public void writeToParcel(Parcel dest, int flags) { 291 dest.writeInt(netId); 292 } 293 294 public static final Creator<Network> CREATOR = 295 new Creator<Network>() { 296 public Network createFromParcel(Parcel in) { 297 int netId = in.readInt(); 298 299 return new Network(netId); 300 } 301 302 public Network[] newArray(int size) { 303 return new Network[size]; 304 } 305 }; 306 307 @Override 308 public boolean equals(Object obj) { 309 if (obj instanceof Network == false) return false; 310 Network other = (Network)obj; 311 return this.netId == other.netId; 312 } 313 314 @Override 315 public int hashCode() { 316 return netId * 11; 317 } 318 319 @Override 320 public String toString() { 321 return Integer.toString(netId); 322 } 323 } 324