1/*
2 * Copyright (C) 2011 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
17package android.net;
18
19import android.os.Parcel;
20import android.os.Parcelable;
21
22import java.net.UnknownHostException;
23import java.net.InetAddress;
24import java.net.Inet4Address;
25import java.net.Inet6Address;
26
27import java.util.Collection;
28
29/**
30 * A simple container for route information.
31 *
32 * In order to be used, a route must have a destination prefix and:
33 *
34 * - A gateway address (next-hop, for gatewayed routes), or
35 * - An interface (for directly-connected routes), or
36 * - Both a gateway and an interface.
37 *
38 * This class does not enforce these constraints because there is code that
39 * uses RouteInfo objects to store directly-connected routes without interfaces.
40 * Such objects cannot be used directly, but can be put into a LinkProperties
41 * object which then specifies the interface.
42 *
43 * @hide
44 */
45public class RouteInfo implements Parcelable {
46    /**
47     * The IP destination address for this route.
48     */
49    private final LinkAddress mDestination;
50
51    /**
52     * The gateway address for this route.
53     */
54    private final InetAddress mGateway;
55
56    /**
57     * The interface for this route.
58     */
59    private final String mInterface;
60
61    private final boolean mIsDefault;
62    private final boolean mIsHost;
63    private final boolean mHasGateway;
64
65    /**
66     * Constructs a RouteInfo object.
67     *
68     * If destination is null, then gateway must be specified and the
69     * constructed route is either the IPv4 default route <code>0.0.0.0</code>
70     * if @gateway is an instance of {@link Inet4Address}, or the IPv6 default
71     * route <code>::/0</code> if gateway is an instance of
72     * {@link Inet6Address}.
73     *
74     * destination and gateway may not both be null.
75     *
76     * @param destination the destination prefix
77     * @param gateway the IP address to route packets through
78     * @param iface the interface name to send packets on
79     */
80    public RouteInfo(LinkAddress destination, InetAddress gateway, String iface) {
81        if (destination == null) {
82            if (gateway != null) {
83                if (gateway instanceof Inet4Address) {
84                    destination = new LinkAddress(Inet4Address.ANY, 0);
85                } else {
86                    destination = new LinkAddress(Inet6Address.ANY, 0);
87                }
88            } else {
89                // no destination, no gateway. invalid.
90                throw new IllegalArgumentException("Invalid arguments passed in: " + gateway + "," +
91                                                   destination);
92            }
93        }
94        if (gateway == null) {
95            if (destination.getAddress() instanceof Inet4Address) {
96                gateway = Inet4Address.ANY;
97            } else {
98                gateway = Inet6Address.ANY;
99            }
100        }
101        mHasGateway = (!gateway.isAnyLocalAddress());
102
103        mDestination = new LinkAddress(NetworkUtils.getNetworkPart(destination.getAddress(),
104                destination.getNetworkPrefixLength()), destination.getNetworkPrefixLength());
105        mGateway = gateway;
106        mInterface = iface;
107        mIsDefault = isDefault();
108        mIsHost = isHost();
109    }
110
111    public RouteInfo(LinkAddress destination, InetAddress gateway) {
112        this(destination, gateway, null);
113    }
114
115    public RouteInfo(InetAddress gateway) {
116        this(null, gateway, null);
117    }
118
119    public RouteInfo(LinkAddress host) {
120        this(host, null, null);
121    }
122
123    public static RouteInfo makeHostRoute(InetAddress host, String iface) {
124        return makeHostRoute(host, null, iface);
125    }
126
127    public static RouteInfo makeHostRoute(InetAddress host, InetAddress gateway, String iface) {
128        if (host == null) return null;
129
130        if (host instanceof Inet4Address) {
131            return new RouteInfo(new LinkAddress(host, 32), gateway, iface);
132        } else {
133            return new RouteInfo(new LinkAddress(host, 128), gateway, iface);
134        }
135    }
136
137    private boolean isHost() {
138        return (mDestination.getAddress() instanceof Inet4Address &&
139                mDestination.getNetworkPrefixLength() == 32) ||
140               (mDestination.getAddress() instanceof Inet6Address &&
141                mDestination.getNetworkPrefixLength() == 128);
142    }
143
144    private boolean isDefault() {
145        boolean val = false;
146        if (mGateway != null) {
147            if (mGateway instanceof Inet4Address) {
148                val = (mDestination == null || mDestination.getNetworkPrefixLength() == 0);
149            } else {
150                val = (mDestination == null || mDestination.getNetworkPrefixLength() == 0);
151            }
152        }
153        return val;
154    }
155
156
157    public LinkAddress getDestination() {
158        return mDestination;
159    }
160
161    public InetAddress getGateway() {
162        return mGateway;
163    }
164
165    public String getInterface() {
166        return mInterface;
167    }
168
169    public boolean isDefaultRoute() {
170        return mIsDefault;
171    }
172
173    public boolean isHostRoute() {
174        return mIsHost;
175    }
176
177    public boolean hasGateway() {
178        return mHasGateway;
179    }
180
181    public String toString() {
182        String val = "";
183        if (mDestination != null) val = mDestination.toString();
184        if (mGateway != null) val += " -> " + mGateway.getHostAddress();
185        return val;
186    }
187
188    public int describeContents() {
189        return 0;
190    }
191
192    public void writeToParcel(Parcel dest, int flags) {
193        if (mDestination == null) {
194            dest.writeByte((byte) 0);
195        } else {
196            dest.writeByte((byte) 1);
197            dest.writeByteArray(mDestination.getAddress().getAddress());
198            dest.writeInt(mDestination.getNetworkPrefixLength());
199        }
200
201        if (mGateway == null) {
202            dest.writeByte((byte) 0);
203        } else {
204            dest.writeByte((byte) 1);
205            dest.writeByteArray(mGateway.getAddress());
206        }
207
208        dest.writeString(mInterface);
209    }
210
211    @Override
212    public boolean equals(Object obj) {
213        if (this == obj) return true;
214
215        if (!(obj instanceof RouteInfo)) return false;
216
217        RouteInfo target = (RouteInfo) obj;
218
219        boolean sameDestination = ( mDestination == null) ?
220                target.getDestination() == null
221                : mDestination.equals(target.getDestination());
222
223        boolean sameAddress = (mGateway == null) ?
224                target.getGateway() == null
225                : mGateway.equals(target.getGateway());
226
227        boolean sameInterface = (mInterface == null) ?
228                target.getInterface() == null
229                : mInterface.equals(target.getInterface());
230
231        return sameDestination && sameAddress && sameInterface
232            && mIsDefault == target.mIsDefault;
233    }
234
235    @Override
236    public int hashCode() {
237        return (mDestination == null ? 0 : mDestination.hashCode() * 41)
238            + (mGateway == null ? 0 :mGateway.hashCode() * 47)
239            + (mInterface == null ? 0 :mInterface.hashCode() * 67)
240            + (mIsDefault ? 3 : 7);
241    }
242
243    public static final Creator<RouteInfo> CREATOR =
244        new Creator<RouteInfo>() {
245        public RouteInfo createFromParcel(Parcel in) {
246            InetAddress destAddr = null;
247            int prefix = 0;
248            InetAddress gateway = null;
249
250            if (in.readByte() == 1) {
251                byte[] addr = in.createByteArray();
252                prefix = in.readInt();
253
254                try {
255                    destAddr = InetAddress.getByAddress(addr);
256                } catch (UnknownHostException e) {}
257            }
258
259            if (in.readByte() == 1) {
260                byte[] addr = in.createByteArray();
261
262                try {
263                    gateway = InetAddress.getByAddress(addr);
264                } catch (UnknownHostException e) {}
265            }
266
267            String iface = in.readString();
268
269            LinkAddress dest = null;
270
271            if (destAddr != null) {
272                dest = new LinkAddress(destAddr, prefix);
273            }
274
275            return new RouteInfo(dest, gateway, iface);
276        }
277
278        public RouteInfo[] newArray(int size) {
279            return new RouteInfo[size];
280        }
281    };
282
283    protected boolean matches(InetAddress destination) {
284        if (destination == null) return false;
285
286        // match the route destination and destination with prefix length
287        InetAddress dstNet = NetworkUtils.getNetworkPart(destination,
288                mDestination.getNetworkPrefixLength());
289
290        return mDestination.getAddress().equals(dstNet);
291    }
292
293    /**
294     * Find the route from a Collection of routes that best matches a given address.
295     * May return null if no routes are applicable.
296     * @param routes a Collection of RouteInfos to chose from
297     * @param dest the InetAddress your trying to get to
298     * @return the RouteInfo from the Collection that best fits the given address
299     */
300    public static RouteInfo selectBestRoute(Collection<RouteInfo> routes, InetAddress dest) {
301        if ((routes == null) || (dest == null)) return null;
302
303        RouteInfo bestRoute = null;
304        // pick a longest prefix match under same address type
305        for (RouteInfo route : routes) {
306            if (NetworkUtils.addressTypeMatches(route.mDestination.getAddress(), dest)) {
307                if ((bestRoute != null) &&
308                        (bestRoute.mDestination.getNetworkPrefixLength() >=
309                        route.mDestination.getNetworkPrefixLength())) {
310                    continue;
311                }
312                if (route.matches(dest)) bestRoute = route;
313            }
314        }
315        return bestRoute;
316    }
317}
318