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 
17 package android.net.dhcp;
18 
19 import java.net.Inet4Address;
20 import java.nio.ByteBuffer;
21 
22 /**
23  * This class implements the DHCP-DECLINE packet.
24  */
25 public class DhcpDeclinePacket extends DhcpPacket {
26     /**
27      * Generates a DECLINE packet with the specified parameters.
28      */
DhcpDeclinePacket(int transId, short secs, Inet4Address clientIp, Inet4Address yourIp, Inet4Address nextIp, Inet4Address relayIp, byte[] clientMac, Inet4Address requestedIpAddress, Inet4Address serverIdentifier)29     DhcpDeclinePacket(int transId, short secs, Inet4Address clientIp, Inet4Address yourIp,
30                       Inet4Address nextIp, Inet4Address relayIp, byte[] clientMac,
31                       Inet4Address requestedIpAddress, Inet4Address serverIdentifier) {
32         super(transId, secs, clientIp, yourIp, nextIp, relayIp, clientMac, false);
33         mRequestedIp = requestedIpAddress;
34         mServerIdentifier = serverIdentifier;
35     }
36 
toString()37     public String toString() {
38         String s = super.toString();
39         return s + " DECLINE";
40     }
41 
42     /**
43      * Fills in a packet with the requested DECLINE attributes.
44      */
buildPacket(int encap, short destUdp, short srcUdp)45     public ByteBuffer buildPacket(int encap, short destUdp, short srcUdp) {
46         ByteBuffer result = ByteBuffer.allocate(MAX_LENGTH);
47 
48         fillInPacket(encap, mClientIp, mYourIp, destUdp, srcUdp, result,
49             DHCP_BOOTREQUEST, false);
50         result.flip();
51         return result;
52     }
53 
54     /**
55      * Adds optional parameters to the DECLINE packet.
56      */
finishPacket(ByteBuffer buffer)57     void finishPacket(ByteBuffer buffer) {
58         addTlv(buffer, DHCP_MESSAGE_TYPE, DHCP_MESSAGE_TYPE_DECLINE);
59         addTlv(buffer, DHCP_CLIENT_IDENTIFIER, getClientId());
60         addTlv(buffer, DHCP_REQUESTED_IP, mRequestedIp);
61         addTlv(buffer, DHCP_SERVER_IDENTIFIER, mServerIdentifier);
62         // RFC 2131 says we MUST NOT include our common client TLVs or the parameter request list.
63         addTlvEnd(buffer);
64     }
65 }
66