/* * Copyright (C) 2010 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 * * http://www.apache.org/licenses/LICENSE-2.0 * * 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 android.net; import android.os.Parcel; import android.os.Parcelable; import android.util.Pair; import java.net.Inet4Address; import java.net.Inet6Address; import java.net.InetAddress; import java.net.InterfaceAddress; import java.net.UnknownHostException; import static android.system.OsConstants.IFA_F_DADFAILED; import static android.system.OsConstants.IFA_F_DEPRECATED; import static android.system.OsConstants.IFA_F_OPTIMISTIC; import static android.system.OsConstants.IFA_F_TENTATIVE; import static android.system.OsConstants.RT_SCOPE_HOST; import static android.system.OsConstants.RT_SCOPE_LINK; import static android.system.OsConstants.RT_SCOPE_SITE; import static android.system.OsConstants.RT_SCOPE_UNIVERSE; /** * Identifies an IP address on a network link. * * A {@code LinkAddress} consists of: * <ul> * <li>An IP address and prefix length (e.g., {@code 2001:db8::1/64} or {@code 192.0.2.1/24}). * The address must be unicast, as multicast addresses cannot be assigned to interfaces. * <li>Address flags: A bitmask of {@code OsConstants.IFA_F_*} values representing properties * of the address (e.g., {@code android.system.OsConstants.IFA_F_OPTIMISTIC}). * <li>Address scope: One of the {@code OsConstants.IFA_F_*} values; defines the scope in which * the address is unique (e.g., * {@code android.system.OsConstants.RT_SCOPE_LINK} or * {@code android.system.OsConstants.RT_SCOPE_UNIVERSE}). * </ul> */ public class LinkAddress implements Parcelable { /** * IPv4 or IPv6 address. */ private InetAddress address; /** * Prefix length. */ private int prefixLength; /** * Address flags. A bitmask of IFA_F_* values. */ private int flags; /** * Address scope. One of the RT_SCOPE_* constants. */ private int scope; /** * Utility function to determines the scope of a unicast address. Per RFC 4291 section 2.5 and * RFC 6724 section 3.2. * @hide */ static int scopeForUnicastAddress(InetAddress addr) { if (addr.isAnyLocalAddress()) { return RT_SCOPE_HOST; } if (addr.isLoopbackAddress() || addr.isLinkLocalAddress()) { return RT_SCOPE_LINK; } // isSiteLocalAddress() returns true for private IPv4 addresses, but RFC 6724 section 3.2 // says that they are assigned global scope. if (!(addr instanceof Inet4Address) && addr.isSiteLocalAddress()) { return RT_SCOPE_SITE; } return RT_SCOPE_UNIVERSE; } /** * Utility function to check if |address| is a Unique Local IPv6 Unicast Address * (a.k.a. "ULA"; RFC 4193). * * Per RFC 4193 section 8, fc00::/7 identifies these addresses. */ private boolean isIPv6ULA() { if (address != null && address instanceof Inet6Address) { byte[] bytes = address.getAddress(); return ((bytes[0] & (byte)0xfe) == (byte)0xfc); } return false; } /** * Utility function for the constructors. */ private void init(InetAddress address, int prefixLength, int flags, int scope) { if (address == null || address.isMulticastAddress() || prefixLength < 0 || ((address instanceof Inet4Address) && prefixLength > 32) || (prefixLength > 128)) { throw new IllegalArgumentException("Bad LinkAddress params " + address + "/" + prefixLength); } this.address = address; this.prefixLength = prefixLength; this.flags = flags; this.scope = scope; } /** * Constructs a new {@code LinkAddress} from an {@code InetAddress} and prefix length, with * the specified flags and scope. Flags and scope are not checked for validity. * @param address The IP address. * @param prefixLength The prefix length. * @param flags A bitmask of {@code IFA_F_*} values representing properties of the address. * @param scope An integer defining the scope in which the address is unique (e.g., * {@link OsConstants#RT_SCOPE_LINK} or {@link OsConstants#RT_SCOPE_SITE}). * @hide */ public LinkAddress(InetAddress address, int prefixLength, int flags, int scope) { init(address, prefixLength, flags, scope); } /** * Constructs a new {@code LinkAddress} from an {@code InetAddress} and a prefix length. * The flags are set to zero and the scope is determined from the address. * @param address The IP address. * @param prefixLength The prefix length. * @hide */ public LinkAddress(InetAddress address, int prefixLength) { this(address, prefixLength, 0, 0); this.scope = scopeForUnicastAddress(address); } /** * Constructs a new {@code LinkAddress} from an {@code InterfaceAddress}. * The flags are set to zero and the scope is determined from the address. * @param interfaceAddress The interface address. * @hide */ public LinkAddress(InterfaceAddress interfaceAddress) { this(interfaceAddress.getAddress(), interfaceAddress.getNetworkPrefixLength()); } /** * Constructs a new {@code LinkAddress} from a string such as "192.0.2.5/24" or * "2001:db8::1/64". The flags are set to zero and the scope is determined from the address. * @param string The string to parse. * @hide */ public LinkAddress(String address) { this(address, 0, 0); this.scope = scopeForUnicastAddress(this.address); } /** * Constructs a new {@code LinkAddress} from a string such as "192.0.2.5/24" or * "2001:db8::1/64", with the specified flags and scope. * @param string The string to parse. * @param flags The address flags. * @param scope The address scope. * @hide */ public LinkAddress(String address, int flags, int scope) { // This may throw an IllegalArgumentException; catching it is the caller's responsibility. Pair<InetAddress, Integer> ipAndMask = NetworkUtils.parseIpAndMask(address); init(ipAndMask.first, ipAndMask.second, flags, scope); } /** * Returns a string representation of this address, such as "192.0.2.1/24" or "2001:db8::1/64". * The string representation does not contain the flags and scope, just the address and prefix * length. */ @Override public String toString() { return address.getHostAddress() + "/" + prefixLength; } /** * Compares this {@code LinkAddress} instance against {@code obj}. Two addresses are equal if * their address, prefix length, flags and scope are equal. Thus, for example, two addresses * that have the same address and prefix length are not equal if one of them is deprecated and * the other is not. * * @param obj the object to be tested for equality. * @return {@code true} if both objects are equal, {@code false} otherwise. */ @Override public boolean equals(Object obj) { if (!(obj instanceof LinkAddress)) { return false; } LinkAddress linkAddress = (LinkAddress) obj; return this.address.equals(linkAddress.address) && this.prefixLength == linkAddress.prefixLength && this.flags == linkAddress.flags && this.scope == linkAddress.scope; } /** * Returns a hashcode for this address. */ @Override public int hashCode() { return address.hashCode() + 11 * prefixLength + 19 * flags + 43 * scope; } /** * Determines whether this {@code LinkAddress} and the provided {@code LinkAddress} * represent the same address. Two {@code LinkAddresses} represent the same address * if they have the same IP address and prefix length, even if their properties are * different. * * @param other the {@code LinkAddress} to compare to. * @return {@code true} if both objects have the same address and prefix length, {@code false} * otherwise. * @hide */ public boolean isSameAddressAs(LinkAddress other) { return address.equals(other.address) && prefixLength == other.prefixLength; } /** * Returns the {@link InetAddress} of this {@code LinkAddress}. */ public InetAddress getAddress() { return address; } /** * Returns the prefix length of this {@code LinkAddress}. */ public int getPrefixLength() { return prefixLength; } /** * Returns the prefix length of this {@code LinkAddress}. * TODO: Delete all callers and remove in favour of getPrefixLength(). * @hide */ public int getNetworkPrefixLength() { return getPrefixLength(); } /** * Returns the flags of this {@code LinkAddress}. */ public int getFlags() { return flags; } /** * Returns the scope of this {@code LinkAddress}. */ public int getScope() { return scope; } /** * Returns true if this {@code LinkAddress} is global scope and preferred. * @hide */ public boolean isGlobalPreferred() { /** * Note that addresses flagged as IFA_F_OPTIMISTIC are * simultaneously flagged as IFA_F_TENTATIVE (when the tentative * state has cleared either DAD has succeeded or failed, and both * flags are cleared regardless). */ return (scope == RT_SCOPE_UNIVERSE && !isIPv6ULA() && (flags & (IFA_F_DADFAILED | IFA_F_DEPRECATED)) == 0L && ((flags & IFA_F_TENTATIVE) == 0L || (flags & IFA_F_OPTIMISTIC) != 0L)); } /** * Implement the Parcelable interface. */ public int describeContents() { return 0; } /** * Implement the Parcelable interface. */ public void writeToParcel(Parcel dest, int flags) { dest.writeByteArray(address.getAddress()); dest.writeInt(prefixLength); dest.writeInt(this.flags); dest.writeInt(scope); } /** * Implement the Parcelable interface. */ public static final Creator<LinkAddress> CREATOR = new Creator<LinkAddress>() { public LinkAddress createFromParcel(Parcel in) { InetAddress address = null; try { address = InetAddress.getByAddress(in.createByteArray()); } catch (UnknownHostException e) { // Nothing we can do here. When we call the constructor, we'll throw an // IllegalArgumentException, because a LinkAddress can't have a null // InetAddress. } int prefixLength = in.readInt(); int flags = in.readInt(); int scope = in.readInt(); return new LinkAddress(address, prefixLength, flags, scope); } public LinkAddress[] newArray(int size) { return new LinkAddress[size]; } }; }