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      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.InetAddress;
     20 import java.nio.ByteBuffer;
     21 
     22 /**
     23  * This class implements the (unused) DHCP-INFORM packet.
     24  */
     25 class DhcpInformPacket extends DhcpPacket {
     26     /**
     27      * Generates an INFORM packet with the specified parameters.
     28      */
     29     DhcpInformPacket(int transId, InetAddress clientIp, InetAddress yourIp,
     30                      InetAddress nextIp, InetAddress relayIp,
     31                      byte[] clientMac) {
     32         super(transId, clientIp, yourIp, nextIp, relayIp, clientMac, false);
     33     }
     34 
     35     public String toString() {
     36         String s = super.toString();
     37         return s + " INFORM";
     38     }
     39 
     40     /**
     41      * Builds an INFORM packet.
     42      */
     43     public ByteBuffer buildPacket(int encap, short destUdp, short srcUdp) {
     44         ByteBuffer result = ByteBuffer.allocate(MAX_LENGTH);
     45 
     46         fillInPacket(encap, mClientIp, mYourIp, destUdp, srcUdp, result,
     47             DHCP_BOOTREQUEST, false);
     48         result.flip();
     49         return result;
     50     }
     51 
     52     /**
     53      * Adds additional parameters to the INFORM packet.
     54      */
     55     void finishPacket(ByteBuffer buffer) {
     56         byte[] clientId = new byte[7];
     57 
     58         clientId[0] = CLIENT_ID_ETHER;
     59         System.arraycopy(mClientMac, 0, clientId, 1, 6);
     60 
     61         addTlv(buffer, DHCP_MESSAGE_TYPE, DHCP_MESSAGE_TYPE_REQUEST);
     62         addTlv(buffer, DHCP_PARAMETER_LIST, mRequestedParams);
     63         addTlvEnd(buffer);
     64     }
     65 
     66     /**
     67      * Informs the state machine of the arrival of an INFORM packet.  Not
     68      * used currently.
     69      */
     70     public void doNextOp(DhcpStateMachine machine) {
     71         InetAddress clientRequest =
     72             mRequestedIp == null ? mClientIp : mRequestedIp;
     73         machine.onInformReceived(mTransId, mClientMac, clientRequest,
     74             mRequestedParams);
     75     }
     76 }
     77