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 com.android.networkstack.tethering.util; 18 19 import android.net.IpPrefix; 20 import android.net.LinkAddress; 21 import android.net.LinkProperties; 22 import android.net.util.NetworkConstants; 23 24 import java.net.Inet4Address; 25 import java.net.InetAddress; 26 import java.util.Collections; 27 import java.util.HashSet; 28 import java.util.Set; 29 30 31 /** 32 * @hide 33 */ 34 public class PrefixUtils { 35 private static final IpPrefix[] MIN_NON_FORWARDABLE_PREFIXES = { 36 pfx("127.0.0.0/8"), // IPv4 loopback 37 pfx("169.254.0.0/16"), // IPv4 link-local, RFC3927#section-8 38 pfx("::/3"), 39 pfx("fe80::/64"), // IPv6 link-local 40 pfx("fc00::/7"), // IPv6 ULA 41 pfx("ff02::/8"), // IPv6 link-local multicast 42 }; 43 44 public static final IpPrefix DEFAULT_WIFI_P2P_PREFIX = pfx("192.168.49.0/24"); 45 46 /** Get non forwardable prefixes. */ getNonForwardablePrefixes()47 public static Set<IpPrefix> getNonForwardablePrefixes() { 48 final HashSet<IpPrefix> prefixes = new HashSet<>(); 49 addNonForwardablePrefixes(prefixes); 50 return prefixes; 51 } 52 53 /** Add non forwardable prefixes. */ addNonForwardablePrefixes(Set<IpPrefix> prefixes)54 public static void addNonForwardablePrefixes(Set<IpPrefix> prefixes) { 55 Collections.addAll(prefixes, MIN_NON_FORWARDABLE_PREFIXES); 56 } 57 58 /** Get local prefixes from |lp|. */ localPrefixesFrom(LinkProperties lp)59 public static Set<IpPrefix> localPrefixesFrom(LinkProperties lp) { 60 final HashSet<IpPrefix> localPrefixes = new HashSet<>(); 61 if (lp == null) return localPrefixes; 62 63 for (LinkAddress addr : lp.getAllLinkAddresses()) { 64 if (addr.getAddress().isLinkLocalAddress()) continue; 65 localPrefixes.add(asIpPrefix(addr)); 66 } 67 // TODO: Add directly-connected routes as well (ones from which we did 68 // not also form a LinkAddress)? 69 70 return localPrefixes; 71 } 72 73 /** Convert LinkAddress |addr| to IpPrefix. */ asIpPrefix(LinkAddress addr)74 public static IpPrefix asIpPrefix(LinkAddress addr) { 75 return new IpPrefix(addr.getAddress(), addr.getPrefixLength()); 76 } 77 78 /** Convert InetAddress |ip| to IpPrefix. */ ipAddressAsPrefix(InetAddress ip)79 public static IpPrefix ipAddressAsPrefix(InetAddress ip) { 80 final int bitLength = (ip instanceof Inet4Address) 81 ? NetworkConstants.IPV4_ADDR_BITS 82 : NetworkConstants.IPV6_ADDR_BITS; 83 return new IpPrefix(ip, bitLength); 84 } 85 pfx(String prefixStr)86 private static IpPrefix pfx(String prefixStr) { 87 return new IpPrefix(prefixStr); 88 } 89 } 90