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// Copyright (c) 1999-2004 Brian Wellington (bwelling@xbill.org)
package org.xbill.DNS;
import java.io.*;
import java.util.*;
/**
* Options - describes Extended DNS (EDNS) properties of a Message.
* No specific options are defined other than those specified in the
* header. An OPT should be generated by Resolver.
*
* EDNS is a method to extend the DNS protocol while providing backwards
* compatibility and not significantly changing the protocol. This
* implementation of EDNS is mostly complete at level 0.
*
* @see Message
* @see Resolver
*
* @author Brian Wellington
*/
public class OPTRecord extends Record {
private static final long serialVersionUID = -6254521894809367938L;
private List options;
OPTRecord() {}
Record
getObject() {
return new OPTRecord();
}
/**
* Creates an OPT Record. This is normally called by SimpleResolver, but can
* also be called by a server.
* @param payloadSize The size of a packet that can be reassembled on the
* sending host.
* @param xrcode The value of the extended rcode field. This is the upper
* 16 bits of the full rcode.
* @param flags Additional message flags.
* @param version The EDNS version that this DNS implementation supports.
* This should be 0 for dnsjava.
* @param options The list of options that comprise the data field. There
* are currently no defined options.
* @see ExtendedFlags
*/
public
OPTRecord(int payloadSize, int xrcode, int version, int flags, List options) {
super(Name.root, Type.OPT, payloadSize, 0);
checkU16("payloadSize", payloadSize);
checkU8("xrcode", xrcode);
checkU8("version", version);
checkU16("flags", flags);
ttl = ((long)xrcode << 24) + ((long)version << 16) + flags;
if (options != null) {
this.options = new ArrayList(options);
}
}
/**
* Creates an OPT Record with no data. This is normally called by
* SimpleResolver, but can also be called by a server.
* @param payloadSize The size of a packet that can be reassembled on the
* sending host.
* @param xrcode The value of the extended rcode field. This is the upper
* 16 bits of the full rcode.
* @param flags Additional message flags.
* @param version The EDNS version that this DNS implementation supports.
* This should be 0 for dnsjava.
* @see ExtendedFlags
*/
public
OPTRecord(int payloadSize, int xrcode, int version, int flags) {
this(payloadSize, xrcode, version, flags, null);
}
/**
* Creates an OPT Record with no data. This is normally called by
* SimpleResolver, but can also be called by a server.
*/
public
OPTRecord(int payloadSize, int xrcode, int version) {
this(payloadSize, xrcode, version, 0, null);
}
void
rrFromWire(DNSInput in) throws IOException {
if (in.remaining() > 0)
options = new ArrayList();
while (in.remaining() > 0) {
EDNSOption option = EDNSOption.fromWire(in);
options.add(option);
}
}
void
rdataFromString(Tokenizer st, Name origin) throws IOException {
throw st.exception("no text format defined for OPT");
}
/** Converts rdata to a String */
String
rrToString() {
StringBuffer sb = new StringBuffer();
if (options != null) {
sb.append(options);
sb.append(" ");
}
sb.append(" ; payload ");
sb.append(getPayloadSize());
sb.append(", xrcode ");
sb.append(getExtendedRcode());
sb.append(", version ");
sb.append(getVersion());
sb.append(", flags ");
sb.append(getFlags());
return sb.toString();
}
/** Returns the maximum allowed payload size. */
public int
getPayloadSize() {
return dclass;
}
/**
* Returns the extended Rcode
* @see Rcode
*/
public int
getExtendedRcode() {
return (int)(ttl >>> 24);
}
/** Returns the highest supported EDNS version */
public int
getVersion() {
return (int)((ttl >>> 16) & 0xFF);
}
/** Returns the EDNS flags */
public int
getFlags() {
return (int)(ttl & 0xFFFF);
}
void
rrToWire(DNSOutput out, Compression c, boolean canonical) {
if (options == null)
return;
Iterator it = options.iterator();
while (it.hasNext()) {
EDNSOption option = (EDNSOption) it.next();
option.toWire(out);
}
}
/**
* Gets all options in the OPTRecord. This returns a list of EDNSOptions.
*/
public List
getOptions() {
if (options == null)
return Collections.EMPTY_LIST;
return Collections.unmodifiableList(options);
}
/**
* Gets all options in the OPTRecord with a specific code. This returns a list
* of EDNSOptions.
*/
public List
getOptions(int code) {
if (options == null)
return Collections.EMPTY_LIST;
List list = Collections.EMPTY_LIST;
for (Iterator it = options.iterator(); it.hasNext(); ) {
EDNSOption opt = (EDNSOption) it.next();
if (opt.getCode() == code) {
if (list == Collections.EMPTY_LIST)
list = new ArrayList();
list.add(opt);
}
}
return list;
}
}
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