1 /* 2 * Copyright (C) 2017 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.util; 18 19 import static android.net.MacAddress.ALL_ZEROS_ADDRESS; 20 import static android.net.util.NetworkConstants.ETHER_MTU; 21 import static android.net.util.NetworkConstants.IPV6_MIN_MTU; 22 import static com.android.internal.util.Preconditions.checkArgument; 23 24 import android.net.MacAddress; 25 import android.text.TextUtils; 26 27 import java.net.NetworkInterface; 28 import java.net.SocketException; 29 30 31 /** 32 * Encapsulate the interface parameters common to IpClient/IpServer components. 33 * 34 * Basically all java.net.NetworkInterface methods throw Exceptions. IpClient 35 * and IpServer (sub)components need most or all of this information at some 36 * point during their lifecycles, so pass only this simplified object around 37 * which can be created once when IpClient/IpServer are told to start. 38 * 39 * @hide 40 */ 41 public class InterfaceParams { 42 public final String name; 43 public final int index; 44 public final MacAddress macAddr; 45 public final int defaultMtu; 46 47 public static InterfaceParams getByName(String name) { 48 final NetworkInterface netif = getNetworkInterfaceByName(name); 49 if (netif == null) return null; 50 51 // Not all interfaces have MAC addresses, e.g. rmnet_data0. 52 final MacAddress macAddr = getMacAddress(netif); 53 54 try { 55 return new InterfaceParams(name, netif.getIndex(), macAddr, netif.getMTU()); 56 } catch (IllegalArgumentException|SocketException e) { 57 return null; 58 } 59 } 60 61 public InterfaceParams(String name, int index, MacAddress macAddr) { 62 this(name, index, macAddr, ETHER_MTU); 63 } 64 65 public InterfaceParams(String name, int index, MacAddress macAddr, int defaultMtu) { 66 checkArgument((!TextUtils.isEmpty(name)), "impossible interface name"); 67 checkArgument((index > 0), "invalid interface index"); 68 this.name = name; 69 this.index = index; 70 this.macAddr = (macAddr != null) ? macAddr : ALL_ZEROS_ADDRESS; 71 this.defaultMtu = (defaultMtu > IPV6_MIN_MTU) ? defaultMtu : IPV6_MIN_MTU; 72 } 73 74 @Override 75 public String toString() { 76 return String.format("%s/%d/%s/%d", name, index, macAddr, defaultMtu); 77 } 78 79 private static NetworkInterface getNetworkInterfaceByName(String name) { 80 try { 81 return NetworkInterface.getByName(name); 82 } catch (NullPointerException|SocketException e) { 83 return null; 84 } 85 } 86 87 private static MacAddress getMacAddress(NetworkInterface netif) { 88 try { 89 return MacAddress.fromBytes(netif.getHardwareAddress()); 90 } catch (IllegalArgumentException|NullPointerException|SocketException e) { 91 return null; 92 } 93 } 94 } 95
