/*
* Copyright (C) 2011 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 java.net.UnknownHostException;
import java.net.InetAddress;
import java.net.Inet4Address;
import java.net.Inet6Address;
import java.util.Collection;
import java.util.Objects;
/**
* Represents a network route.
* <p>
* This is used both to describe static network configuration and live network
* configuration information.
*
* A route contains three pieces of information:
* <ul>
* <li>a destination {@link IpPrefix} specifying the network destinations covered by this route.
* If this is {@code null} it indicates a default route of the address family (IPv4 or IPv6)
* implied by the gateway IP address.
* <li>a gateway {@link InetAddress} indicating the next hop to use. If this is {@code null} it
* indicates a directly-connected route.
* <li>an interface (which may be unspecified).
* </ul>
* Either the destination or the gateway may be {@code null}, but not both. If the
* destination and gateway are both specified, they must be of the same address family
* (IPv4 or IPv6).
*/
public final class RouteInfo implements Parcelable {
/**
* The IP destination address for this route.
*/
private final IpPrefix mDestination;
/**
* The gateway address for this route.
*/
private final InetAddress mGateway;
/**
* The interface for this route.
*/
private final String mInterface;
/** Unicast route. @hide */
public static final int RTN_UNICAST = 1;
/** Unreachable route. @hide */
public static final int RTN_UNREACHABLE = 7;
/** Throw route. @hide */
public static final int RTN_THROW = 9;
/**
* The type of this route; one of the RTN_xxx constants above.
*/
private final int mType;
// Derived data members.
// TODO: remove these.
private final boolean mIsHost;
private final boolean mHasGateway;
/**
* Constructs a RouteInfo object.
*
* If destination is null, then gateway must be specified and the
* constructed route is either the IPv4 default route <code>0.0.0.0</code>
* if the gateway is an instance of {@link Inet4Address}, or the IPv6 default
* route <code>::/0</code> if gateway is an instance of
* {@link Inet6Address}.
* <p>
* destination and gateway may not both be null.
*
* @param destination the destination prefix
* @param gateway the IP address to route packets through
* @param iface the interface name to send packets on
*
* @hide
*/
public RouteInfo(IpPrefix destination, InetAddress gateway, String iface, int type) {
switch (type) {
case RTN_UNICAST:
case RTN_UNREACHABLE:
case RTN_THROW:
// TODO: It would be nice to ensure that route types that don't have nexthops or
// interfaces, such as unreachable or throw, can't be created if an interface or
// a gateway is specified. This is a bit too complicated to do at the moment
// because:
//
// - LinkProperties sets the interface on routes added to it, and modifies the
// interfaces of all the routes when its interface name changes.
// - Even when the gateway is null, we store a non-null gateway here.
//
// For now, we just rely on the code that sets routes to do things properly.
break;
default:
throw new IllegalArgumentException("Unknown route type " + type);
}
if (destination == null) {
if (gateway != null) {
if (gateway instanceof Inet4Address) {
destination = new IpPrefix(Inet4Address.ANY, 0);
} else {
destination = new IpPrefix(Inet6Address.ANY, 0);
}
} else {
// no destination, no gateway. invalid.
throw new IllegalArgumentException("Invalid arguments passed in: " + gateway + "," +
destination);
}
}
// TODO: set mGateway to null if there is no gateway. This is more correct, saves space, and
// matches the documented behaviour. Before we can do this we need to fix all callers (e.g.,
// ConnectivityService) to stop doing things like r.getGateway().equals(), ... .
if (gateway == null) {
if (destination.getAddress() instanceof Inet4Address) {
gateway = Inet4Address.ANY;
} else {
gateway = Inet6Address.ANY;
}
}
mHasGateway = (!gateway.isAnyLocalAddress());
if ((destination.getAddress() instanceof Inet4Address &&
(gateway instanceof Inet4Address == false)) ||
(destination.getAddress() instanceof Inet6Address &&
(gateway instanceof Inet6Address == false))) {
throw new IllegalArgumentException("address family mismatch in RouteInfo constructor");
}
mDestination = destination; // IpPrefix objects are immutable.
mGateway = gateway; // InetAddress objects are immutable.
mInterface = iface; // Strings are immutable.
mType = type;
mIsHost = isHost();
}
/**
* @hide
*/
public RouteInfo(IpPrefix destination, InetAddress gateway, String iface) {
this(destination, gateway, iface, RTN_UNICAST);
}
/**
* @hide
*/
public RouteInfo(LinkAddress destination, InetAddress gateway, String iface) {
this(destination == null ? null :
new IpPrefix(destination.getAddress(), destination.getPrefixLength()),
gateway, iface);
}
/**
* Constructs a {@code RouteInfo} object.
*
* If destination is null, then gateway must be specified and the
* constructed route is either the IPv4 default route <code>0.0.0.0</code>
* if the gateway is an instance of {@link Inet4Address}, or the IPv6 default
* route <code>::/0</code> if gateway is an instance of {@link Inet6Address}.
* <p>
* Destination and gateway may not both be null.
*
* @param destination the destination address and prefix in an {@link IpPrefix}
* @param gateway the {@link InetAddress} to route packets through
*
* @hide
*/
public RouteInfo(IpPrefix destination, InetAddress gateway) {
this(destination, gateway, null);
}
/**
* @hide
*
* TODO: Remove this.
*/
public RouteInfo(LinkAddress destination, InetAddress gateway) {
this(destination, gateway, null);
}
/**
* Constructs a default {@code RouteInfo} object.
*
* @param gateway the {@link InetAddress} to route packets through
*
* @hide
*/
public RouteInfo(InetAddress gateway) {
this((IpPrefix) null, gateway, null);
}
/**
* Constructs a {@code RouteInfo} object representing a direct connected subnet.
*
* @param destination the {@link IpPrefix} describing the address and prefix
* length of the subnet.
*
* @hide
*/
public RouteInfo(IpPrefix destination) {
this(destination, null, null);
}
/**
* @hide
*/
public RouteInfo(LinkAddress destination) {
this(destination, null, null);
}
/**
* @hide
*/
public RouteInfo(IpPrefix destination, int type) {
this(destination, null, null, type);
}
/**
* @hide
*/
public static RouteInfo makeHostRoute(InetAddress host, String iface) {
return makeHostRoute(host, null, iface);
}
/**
* @hide
*/
public static RouteInfo makeHostRoute(InetAddress host, InetAddress gateway, String iface) {
if (host == null) return null;
if (host instanceof Inet4Address) {
return new RouteInfo(new IpPrefix(host, 32), gateway, iface);
} else {
return new RouteInfo(new IpPrefix(host, 128), gateway, iface);
}
}
private boolean isHost() {
return (mDestination.getAddress() instanceof Inet4Address &&
mDestination.getPrefixLength() == 32) ||
(mDestination.getAddress() instanceof Inet6Address &&
mDestination.getPrefixLength() == 128);
}
/**
* Retrieves the destination address and prefix length in the form of an {@link IpPrefix}.
*
* @return {@link IpPrefix} specifying the destination. This is never {@code null}.
*/
public IpPrefix getDestination() {
return mDestination;
}
/**
* TODO: Convert callers to use IpPrefix and then remove.
* @hide
*/
public LinkAddress getDestinationLinkAddress() {
return new LinkAddress(mDestination.getAddress(), mDestination.getPrefixLength());
}
/**
* Retrieves the gateway or next hop {@link InetAddress} for this route.
*
* @return {@link InetAddress} specifying the gateway or next hop. This may be
* {@code null} for a directly-connected route."
*/
public InetAddress getGateway() {
return mGateway;
}
/**
* Retrieves the interface used for this route if specified, else {@code null}.
*
* @return The name of the interface used for this route.
*/
public String getInterface() {
return mInterface;
}
/**
* Retrieves the type of this route.
*
* @return The type of this route; one of the {@code RTN_xxx} constants defined in this class.
*
* @hide
*/
public int getType() {
return mType;
}
/**
* Indicates if this route is a default route (ie, has no destination specified).
*
* @return {@code true} if the destination has a prefix length of 0.
*/
public boolean isDefaultRoute() {
return mType == RTN_UNICAST && mDestination.getPrefixLength() == 0;
}
/**
* Indicates if this route is an IPv4 default route.
* @hide
*/
public boolean isIPv4Default() {
return isDefaultRoute() && mDestination.getAddress() instanceof Inet4Address;
}
/**
* Indicates if this route is an IPv6 default route.
* @hide
*/
public boolean isIPv6Default() {
return isDefaultRoute() && mDestination.getAddress() instanceof Inet6Address;
}
/**
* Indicates if this route is a host route (ie, matches only a single host address).
*
* @return {@code true} if the destination has a prefix length of 32 or 128 for IPv4 or IPv6,
* respectively.
* @hide
*/
public boolean isHostRoute() {
return mIsHost;
}
/**
* Indicates if this route has a next hop ({@code true}) or is directly-connected
* ({@code false}).
*
* @return {@code true} if a gateway is specified
* @hide
*/
public boolean hasGateway() {
return mHasGateway;
}
/**
* Determines whether the destination and prefix of this route includes the specified
* address.
*
* @param destination A {@link InetAddress} to test to see if it would match this route.
* @return {@code true} if the destination and prefix length cover the given address.
*/
public boolean matches(InetAddress destination) {
if (destination == null) return false;
// match the route destination and destination with prefix length
InetAddress dstNet = NetworkUtils.getNetworkPart(destination,
mDestination.getPrefixLength());
return mDestination.getAddress().equals(dstNet);
}
/**
* Find the route from a Collection of routes that best matches a given address.
* May return null if no routes are applicable.
* @param routes a Collection of RouteInfos to chose from
* @param dest the InetAddress your trying to get to
* @return the RouteInfo from the Collection that best fits the given address
*
* @hide
*/
public static RouteInfo selectBestRoute(Collection<RouteInfo> routes, InetAddress dest) {
if ((routes == null) || (dest == null)) return null;
RouteInfo bestRoute = null;
// pick a longest prefix match under same address type
for (RouteInfo route : routes) {
if (NetworkUtils.addressTypeMatches(route.mDestination.getAddress(), dest)) {
if ((bestRoute != null) &&
(bestRoute.mDestination.getPrefixLength() >=
route.mDestination.getPrefixLength())) {
continue;
}
if (route.matches(dest)) bestRoute = route;
}
}
return bestRoute;
}
/**
* Returns a human-readable description of this object.
*/
public String toString() {
String val = "";
if (mDestination != null) val = mDestination.toString();
if (mType == RTN_UNREACHABLE) {
val += " unreachable";
} else if (mType == RTN_THROW) {
val += " throw";
} else {
val += " ->";
if (mGateway != null) val += " " + mGateway.getHostAddress();
if (mInterface != null) val += " " + mInterface;
if (mType != RTN_UNICAST) {
val += " unknown type " + mType;
}
}
return val;
}
/**
* Compares this RouteInfo object against the specified object and indicates if they are equal.
* @return {@code true} if the objects are equal, {@code false} otherwise.
*/
public boolean equals(Object obj) {
if (this == obj) return true;
if (!(obj instanceof RouteInfo)) return false;
RouteInfo target = (RouteInfo) obj;
return Objects.equals(mDestination, target.getDestination()) &&
Objects.equals(mGateway, target.getGateway()) &&
Objects.equals(mInterface, target.getInterface()) &&
mType == target.getType();
}
/**
* Returns a hashcode for this <code>RouteInfo</code> object.
*/
public int hashCode() {
return (mDestination.hashCode() * 41)
+ (mGateway == null ? 0 :mGateway.hashCode() * 47)
+ (mInterface == null ? 0 :mInterface.hashCode() * 67)
+ (mType * 71);
}
/**
* Implement the Parcelable interface
*/
public int describeContents() {
return 0;
}
/**
* Implement the Parcelable interface
*/
public void writeToParcel(Parcel dest, int flags) {
dest.writeParcelable(mDestination, flags);
byte[] gatewayBytes = (mGateway == null) ? null : mGateway.getAddress();
dest.writeByteArray(gatewayBytes);
dest.writeString(mInterface);
dest.writeInt(mType);
}
/**
* Implement the Parcelable interface.
*/
public static final Creator<RouteInfo> CREATOR =
new Creator<RouteInfo>() {
public RouteInfo createFromParcel(Parcel in) {
IpPrefix dest = in.readParcelable(null);
InetAddress gateway = null;
byte[] addr = in.createByteArray();
try {
gateway = InetAddress.getByAddress(addr);
} catch (UnknownHostException e) {}
String iface = in.readString();
int type = in.readInt();
return new RouteInfo(dest, gateway, iface, type);
}
public RouteInfo[] newArray(int size) {
return new RouteInfo[size];
}
};
}
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