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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 android.util.Log;
     20 
     21 import java.net.InetAddress;
     22 import java.net.Inet4Address;
     23 import java.nio.ByteBuffer;
     24 
     25 /**
     26  * This class implements the DHCP-REQUEST packet.
     27  */
     28 class DhcpRequestPacket extends DhcpPacket {
     29     /**
     30      * Generates a REQUEST packet with the specified parameters.
     31      */
     32     DhcpRequestPacket(int transId, InetAddress clientIp, byte[] clientMac,
     33                       boolean broadcast) {
     34         super(transId, clientIp, Inet4Address.ANY, Inet4Address.ANY,
     35           Inet4Address.ANY, clientMac, broadcast);
     36     }
     37 
     38     public String toString() {
     39         String s = super.toString();
     40         return s + " REQUEST, desired IP " + mRequestedIp + " from host '"
     41             + mHostName + "', param list length "
     42             + (mRequestedParams == null ? 0 : mRequestedParams.length);
     43     }
     44 
     45     /**
     46      * Fills in a packet with the requested REQUEST attributes.
     47      */
     48     public ByteBuffer buildPacket(int encap, short destUdp, short srcUdp) {
     49         ByteBuffer result = ByteBuffer.allocate(MAX_LENGTH);
     50 
     51         fillInPacket(encap, Inet4Address.ALL, Inet4Address.ANY, destUdp, srcUdp,
     52             result, DHCP_BOOTREQUEST, mBroadcast);
     53         result.flip();
     54         return result;
     55     }
     56 
     57     /**
     58      * Adds the optional parameters to the client-generated REQUEST packet.
     59      */
     60     void finishPacket(ByteBuffer buffer) {
     61         byte[] clientId = new byte[7];
     62 
     63         // assemble client identifier
     64         clientId[0] = CLIENT_ID_ETHER;
     65         System.arraycopy(mClientMac, 0, clientId, 1, 6);
     66 
     67         addTlv(buffer, DHCP_MESSAGE_TYPE, DHCP_MESSAGE_TYPE_REQUEST);
     68         addTlv(buffer, DHCP_PARAMETER_LIST, mRequestedParams);
     69         addTlv(buffer, DHCP_REQUESTED_IP, mRequestedIp);
     70         addTlv(buffer, DHCP_SERVER_IDENTIFIER, mServerIdentifier);
     71         addTlv(buffer, DHCP_CLIENT_IDENTIFIER, clientId);
     72         addTlvEnd(buffer);
     73     }
     74 
     75     /**
     76      * Notifies the specified state machine of the REQUEST packet parameters.
     77      */
     78     public void doNextOp(DhcpStateMachine machine) {
     79         InetAddress clientRequest =
     80             mRequestedIp == null ? mClientIp : mRequestedIp;
     81         Log.v(TAG, "requested IP is " + mRequestedIp + " and client IP is " +
     82             mClientIp);
     83         machine.onRequestReceived(mBroadcast, mTransId, mClientMac,
     84             clientRequest, mRequestedParams, mHostName);
     85     }
     86 }
     87