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-ACK packet. 24 */ 25 class DhcpAckPacket extends DhcpPacket { 26 27 /** 28 * The address of the server which sent this packet. 29 */ 30 private final Inet4Address mSrcIp; 31 DhcpAckPacket(int transId, short secs, boolean broadcast, Inet4Address serverAddress, Inet4Address relayIp, Inet4Address clientIp, Inet4Address yourIp, byte[] clientMac)32 DhcpAckPacket(int transId, short secs, boolean broadcast, Inet4Address serverAddress, 33 Inet4Address relayIp, Inet4Address clientIp, Inet4Address yourIp, byte[] clientMac) { 34 super(transId, secs, clientIp, yourIp, serverAddress, relayIp, clientMac, broadcast); 35 mBroadcast = broadcast; 36 mSrcIp = serverAddress; 37 } 38 toString()39 public String toString() { 40 String s = super.toString(); 41 String dnsServers = " DNS servers: "; 42 43 for (Inet4Address dnsServer: mDnsServers) { 44 dnsServers += dnsServer.toString() + " "; 45 } 46 47 return s + " ACK: your new IP " + mYourIp + 48 ", netmask " + mSubnetMask + 49 ", gateways " + mGateways + dnsServers + 50 ", lease time " + mLeaseTime; 51 } 52 53 /** 54 * Fills in a packet with the requested ACK parameters. 55 */ buildPacket(int encap, short destUdp, short srcUdp)56 public ByteBuffer buildPacket(int encap, short destUdp, short srcUdp) { 57 ByteBuffer result = ByteBuffer.allocate(MAX_LENGTH); 58 Inet4Address destIp = mBroadcast ? INADDR_BROADCAST : mYourIp; 59 Inet4Address srcIp = mBroadcast ? INADDR_ANY : mSrcIp; 60 61 fillInPacket(encap, destIp, srcIp, destUdp, srcUdp, result, 62 DHCP_BOOTREPLY, mBroadcast); 63 result.flip(); 64 return result; 65 } 66 67 /** 68 * Adds the optional parameters to the client-generated ACK packet. 69 */ finishPacket(ByteBuffer buffer)70 void finishPacket(ByteBuffer buffer) { 71 addTlv(buffer, DHCP_MESSAGE_TYPE, DHCP_MESSAGE_TYPE_ACK); 72 addTlv(buffer, DHCP_SERVER_IDENTIFIER, mServerIdentifier); 73 74 addCommonServerTlvs(buffer); 75 addTlvEnd(buffer); 76 } 77 78 /** 79 * Un-boxes an Integer, returning 0 if a null reference is supplied. 80 */ getInt(Integer v)81 private static final int getInt(Integer v) { 82 if (v == null) { 83 return 0; 84 } else { 85 return v.intValue(); 86 } 87 } 88 } 89