1/*
2 * Copyright (C) 2010 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.dhcp;
18
19import java.net.InetAddress;
20import java.net.Inet4Address;
21import java.nio.ByteBuffer;
22
23/**
24 * This class implements the DHCP-DISCOVER packet.
25 */
26class DhcpDiscoverPacket extends DhcpPacket {
27    /**
28     * Generates a DISCOVER packet with the specified parameters.
29     */
30    DhcpDiscoverPacket(int transId, byte[] clientMac, boolean broadcast) {
31        super(transId, Inet4Address.ANY, Inet4Address.ANY, Inet4Address.ANY,
32            Inet4Address.ANY, clientMac, broadcast);
33    }
34
35    public String toString() {
36        String s = super.toString();
37        return s + " DISCOVER " +
38                (mBroadcast ? "broadcast " : "unicast ");
39    }
40
41    /**
42     * Fills in a packet with the requested DISCOVER parameters.
43     */
44    public ByteBuffer buildPacket(int encap, short destUdp, short srcUdp) {
45        ByteBuffer result = ByteBuffer.allocate(MAX_LENGTH);
46        InetAddress destIp = Inet4Address.ALL;
47
48        fillInPacket(encap, Inet4Address.ALL, Inet4Address.ANY, destUdp, srcUdp,
49            result, DHCP_BOOTREQUEST, true);
50        result.flip();
51        return result;
52    }
53
54    /**
55     * Adds optional parameters to a DISCOVER packet.
56     */
57    void finishPacket(ByteBuffer buffer) {
58        addTlv(buffer, DHCP_MESSAGE_TYPE, DHCP_MESSAGE_TYPE_DISCOVER);
59        addTlv(buffer, DHCP_PARAMETER_LIST, mRequestedParams);
60        addTlvEnd(buffer);
61    }
62
63    /**
64     * Informs the state machine of the arrival of a DISCOVER packet.
65     */
66    public void doNextOp(DhcpStateMachine machine) {
67        // currently omitted: host name
68        machine.onDiscoverReceived(mBroadcast, mTransId, mClientMac,
69            mRequestedParams);
70    }
71}
72