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.net.Inet4Address; 21 import java.nio.ByteBuffer; 22 23 /** 24 * This class implements the DHCP-ACK packet. 25 */ 26 class DhcpAckPacket extends DhcpPacket { 27 28 /** 29 * The address of the server which sent this packet. 30 */ 31 private final InetAddress mSrcIp; 32 33 DhcpAckPacket(int transId, boolean broadcast, InetAddress serverAddress, 34 InetAddress clientIp, byte[] clientMac) { 35 super(transId, Inet4Address.ANY, clientIp, serverAddress, 36 Inet4Address.ANY, clientMac, broadcast); 37 mBroadcast = broadcast; 38 mSrcIp = serverAddress; 39 } 40 41 public String toString() { 42 String s = super.toString(); 43 String dnsServers = " DNS servers: "; 44 45 for (InetAddress dnsServer: mDnsServers) { 46 dnsServers += dnsServer.toString() + " "; 47 } 48 49 return s + " ACK: your new IP " + mYourIp + 50 ", netmask " + mSubnetMask + 51 ", gateway " + mGateway + dnsServers + 52 ", lease time " + mLeaseTime; 53 } 54 55 /** 56 * Fills in a packet with the requested ACK parameters. 57 */ 58 public ByteBuffer buildPacket(int encap, short destUdp, short srcUdp) { 59 ByteBuffer result = ByteBuffer.allocate(MAX_LENGTH); 60 InetAddress destIp = mBroadcast ? Inet4Address.ALL : mYourIp; 61 InetAddress srcIp = mBroadcast ? Inet4Address.ANY : mSrcIp; 62 63 fillInPacket(encap, destIp, srcIp, destUdp, srcUdp, result, 64 DHCP_BOOTREPLY, mBroadcast); 65 result.flip(); 66 return result; 67 } 68 69 /** 70 * Adds the optional parameters to the client-generated ACK packet. 71 */ 72 void finishPacket(ByteBuffer buffer) { 73 addTlv(buffer, DHCP_MESSAGE_TYPE, DHCP_MESSAGE_TYPE_ACK); 74 addTlv(buffer, DHCP_SERVER_IDENTIFIER, mServerIdentifier); 75 addTlv(buffer, DHCP_LEASE_TIME, mLeaseTime); 76 77 // the client should renew at 1/2 the lease-expiry interval 78 if (mLeaseTime != null) { 79 addTlv(buffer, DHCP_RENEWAL_TIME, 80 Integer.valueOf(mLeaseTime.intValue() / 2)); 81 } 82 83 addTlv(buffer, DHCP_SUBNET_MASK, mSubnetMask); 84 addTlv(buffer, DHCP_ROUTER, mGateway); 85 addTlv(buffer, DHCP_DOMAIN_NAME, mDomainName); 86 addTlv(buffer, DHCP_BROADCAST_ADDRESS, mBroadcastAddress); 87 addTlv(buffer, DHCP_DNS_SERVER, mDnsServers); 88 addTlvEnd(buffer); 89 } 90 91 /** 92 * Un-boxes an Integer, returning 0 if a null reference is supplied. 93 */ 94 private static final int getInt(Integer v) { 95 if (v == null) { 96 return 0; 97 } else { 98 return v.intValue(); 99 } 100 } 101 102 /** 103 * Notifies the specified state machine of the ACK packet parameters. 104 */ 105 public void doNextOp(DhcpStateMachine machine) { 106 machine.onAckReceived(mYourIp, mSubnetMask, mGateway, mDnsServers, 107 mServerIdentifier, getInt(mLeaseTime)); 108 } 109 } 110