| /* |
| * 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.Inet4Address; |
| import java.nio.ByteBuffer; |
| |
| /** |
| * This class implements the DHCP-NAK packet. |
| */ |
| class DhcpNakPacket extends DhcpPacket { |
| /** |
| * Generates a NAK packet with the specified parameters. |
| */ |
| DhcpNakPacket(int transId, short secs, Inet4Address relayIp, byte[] clientMac, |
| boolean broadcast) { |
| super(transId, secs, INADDR_ANY /* clientIp */, INADDR_ANY /* yourIp */, |
| INADDR_ANY /* nextIp */, relayIp, clientMac, broadcast); |
| } |
| |
| public String toString() { |
| String s = super.toString(); |
| return s + " NAK, reason " + (mMessage == null ? "(none)" : mMessage); |
| } |
| |
| /** |
| * Fills in a packet with the requested NAK attributes. |
| */ |
| public ByteBuffer buildPacket(int encap, short destUdp, short srcUdp) { |
| ByteBuffer result = ByteBuffer.allocate(MAX_LENGTH); |
| // Constructor does not set values for layers <= 3: use empty values |
| Inet4Address destIp = INADDR_ANY; |
| Inet4Address srcIp = INADDR_ANY; |
| |
| fillInPacket(encap, destIp, srcIp, destUdp, srcUdp, result, DHCP_BOOTREPLY, mBroadcast); |
| result.flip(); |
| return result; |
| } |
| |
| /** |
| * Adds the optional parameters to the client-generated NAK packet. |
| */ |
| void finishPacket(ByteBuffer buffer) { |
| addTlv(buffer, DHCP_MESSAGE_TYPE, DHCP_MESSAGE_TYPE_NAK); |
| addTlv(buffer, DHCP_SERVER_IDENTIFIER, mServerIdentifier); |
| addTlv(buffer, DHCP_MESSAGE, mMessage); |
| addTlvEnd(buffer); |
| } |
| } |