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/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.net.dhcp;
import java.net.InetAddress;
import java.net.Inet4Address;
import java.nio.ByteBuffer;
import java.util.List;
/**
* This class implements the DHCP-OFFER packet.
*/
class DhcpOfferPacket extends DhcpPacket {
/**
* The IP address of the server which sent this packet.
*/
private final InetAddress mSrcIp;
/**
* Generates a OFFER packet with the specified parameters.
*/
DhcpOfferPacket(int transId, boolean broadcast, InetAddress serverAddress,
InetAddress clientIp, byte[] clientMac) {
super(transId, Inet4Address.ANY, clientIp, Inet4Address.ANY,
Inet4Address.ANY, clientMac, broadcast);
mSrcIp = serverAddress;
}
public String toString() {
String s = super.toString();
String dnsServers = ", DNS servers: ";
if (mDnsServers != null) {
for (InetAddress dnsServer: mDnsServers) {
dnsServers += dnsServer + " ";
}
}
return s + " OFFER, ip " + mYourIp + ", mask " + mSubnetMask +
dnsServers + ", gateway " + mGateway +
" lease time " + mLeaseTime + ", domain " + mDomainName;
}
/**
* Fills in a packet with the specified OFFER attributes.
*/
public ByteBuffer buildPacket(int encap, short destUdp, short srcUdp) {
ByteBuffer result = ByteBuffer.allocate(MAX_LENGTH);
InetAddress destIp = mBroadcast ? Inet4Address.ALL : mYourIp;
InetAddress srcIp = mBroadcast ? Inet4Address.ANY : mSrcIp;
fillInPacket(encap, destIp, srcIp, destUdp, srcUdp, result,
DHCP_BOOTREPLY, mBroadcast);
result.flip();
return result;
}
/**
* Adds the optional parameters to the server-generated OFFER packet.
*/
void finishPacket(ByteBuffer buffer) {
addTlv(buffer, DHCP_MESSAGE_TYPE, DHCP_MESSAGE_TYPE_OFFER);
addTlv(buffer, DHCP_SERVER_IDENTIFIER, mServerIdentifier);
addTlv(buffer, DHCP_LEASE_TIME, mLeaseTime);
// the client should renew at 1/2 the lease-expiry interval
if (mLeaseTime != null) {
addTlv(buffer, DHCP_RENEWAL_TIME,
Integer.valueOf(mLeaseTime.intValue() / 2));
}
addTlv(buffer, DHCP_SUBNET_MASK, mSubnetMask);
addTlv(buffer, DHCP_ROUTER, mGateway);
addTlv(buffer, DHCP_DOMAIN_NAME, mDomainName);
addTlv(buffer, DHCP_BROADCAST_ADDRESS, mBroadcastAddress);
addTlv(buffer, DHCP_DNS_SERVER, mDnsServers);
addTlvEnd(buffer);
}
/**
* Notifies the state machine of the OFFER packet parameters.
*/
public void doNextOp(DhcpStateMachine machine) {
machine.onOfferReceived(mBroadcast, mTransId, mClientMac, mYourIp,
mServerIdentifier);
}
}
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