zonetransferin.java

linux下建立JAVA虚拟机的源码KAFFE

private void
sendQuery() throws IOException {
	Record question = Record.newRecord(zname, qtype, dclass);

	Message query = new Message();
	query.getHeader().setOpcode(Opcode.QUERY);
	query.addRecord(question, Section.QUESTION);
	if (qtype == Type.IXFR) {
		Record soa = new SOARecord(zname, dclass, 0, Name.root,
					   Name.root, ixfr_serial,
					   0, 0, 0, 0);
		query.addRecord(soa, Section.AUTHORITY);
	}
	if (tsig != null) {
		tsig.apply(query, null);
		verifier = new TSIG.StreamVerifier(tsig, query.getTSIG());
	}
	byte [] out = query.toWire(Message.MAXLENGTH);
	client.send(out);
}

private long
getSOASerial(Record rec) {
	SOARecord soa = (SOARecord) rec;
	return soa.getSerial();
}

private void
logxfr(String s) {
	if (Options.check("verbose"))
		System.out.println(zname + ": " + s);
}

private void
fail(String s) throws ZoneTransferException {
	throw new ZoneTransferException(s);
}

private void
fallback() throws ZoneTransferException {
	if (!want_fallback)
		fail("server doesn't support IXFR");

	logxfr("falling back to AXFR");
	qtype = Type.AXFR;
	state = INITIALSOA;
}

private void
parseRR(Record rec) throws ZoneTransferException {
	Name name = rec.getName();
	int type = rec.getType();
	Delta delta;

	switch (state) {
	case INITIALSOA:
		if (type != Type.SOA)
			fail("missing initial SOA");
		initialsoa = rec;
		// Remember the serial number in the intial SOA; we need it
		// to recognize the end of an IXFR.
		end_serial = getSOASerial(rec);
		if (qtype == Type.IXFR && end_serial <= ixfr_serial) {
			logxfr("up to date");
			state = END;
			break;
		}
		state = FIRSTDATA;
		break;

	case FIRSTDATA:
		// If the transfer begins with 1 SOA, it's an AXFR.
		// If it begins with 2 SOAs, it's an IXFR.
		if (qtype == Type.IXFR && type == Type.SOA &&
		    getSOASerial(rec) == ixfr_serial)
		{
			rtype = Type.IXFR;
			ixfr = new ArrayList();
			logxfr("got incremental response");
			state = IXFR_DELSOA;
		} else {
			rtype = Type.AXFR;
			axfr = new ArrayList();
			axfr.add(initialsoa);
			logxfr("got nonincremental response");
			state = AXFR;
		}
		parseRR(rec); // Restart...
		return;

	case IXFR_DELSOA:
		delta = new Delta();
		ixfr.add(delta);
		delta.start = getSOASerial(rec);
		delta.deletes.add(rec);
		state = IXFR_DEL;
		break;

	case IXFR_DEL:
		if (type == Type.SOA) {
			current_serial = getSOASerial(rec);
			state = IXFR_ADDSOA;
			parseRR(rec); // Restart...
			return;
		}
		delta = (Delta) ixfr.get(ixfr.size() - 1);
		delta.deletes.add(rec);
		break;

	case IXFR_ADDSOA:
		delta = (Delta) ixfr.get(ixfr.size() - 1);
		delta.end = getSOASerial(rec);
		delta.adds.add(rec);
		state = IXFR_ADD;
		break;

	case IXFR_ADD:
		if (type == Type.SOA) {
			long soa_serial = getSOASerial(rec);
			if (soa_serial == end_serial) {
				state = END;
				break;
			} else if (soa_serial != current_serial) {
				fail("IXFR out of sync: expected serial " +
				     current_serial + " , got " + soa_serial);
			} else {
				state = IXFR_DELSOA;
				parseRR(rec); // Restart...
				return;
			}
		}
		delta = (Delta) ixfr.get(ixfr.size() - 1);
		delta.adds.add(rec);
		break;

	case AXFR:
		// Old BINDs sent cross class A records for non IN classes.
		if (type == Type.A && rec.getDClass() != dclass)
			break;
		axfr.add(rec);
		if (type == Type.SOA) {
			state = END;
		}
		break;

	case END:
		fail("extra data");
		break;

	default:
		fail("invalid state");
		break;
	}
}

private void
closeConnection() {
	try {
		client.cleanup();
	}
	catch (IOException e) {
	}
}

private Message
parseMessage(byte [] b) throws WireParseException {
	try {
		return new Message(b);
	}
	catch (IOException e) {
		if (e instanceof WireParseException)
			throw (WireParseException) e;
		throw new WireParseException("Error parsing message");
	}
}

private void
doxfr() throws IOException, ZoneTransferException {
	sendQuery();
	while (state != END) {
		byte [] in = client.recv();
		Message response =  parseMessage(in);
		if (response.getHeader().getRcode() == Rcode.NOERROR &&
		    verifier != null)
		{
			TSIGRecord tsigrec = response.getTSIG();

			int error = verifier.verify(response, in);
			if (error == Rcode.NOERROR && tsigrec != null)
				response.tsigState = Message.TSIG_VERIFIED;
			else if (error == Rcode.NOERROR)
				response.tsigState = Message.TSIG_INTERMEDIATE;
			else
				fail("TSIG failure");
		}

		Record [] answers = response.getSectionArray(Section.ANSWER);

		if (state == INITIALSOA) {
			int rcode = response.getRcode();
			if (rcode != Rcode.NOERROR) {
				if (qtype == Type.IXFR &&
				    rcode == Rcode.NOTIMP)
				{
					fallback();
					doxfr();
					return;
				}
				fail(Rcode.string(rcode));
			}

			Record question = response.getQuestion();
			if (question != null && question.getType() != qtype) {
				fail("invalid question section");
			}

			if (answers.length == 0 && qtype == Type.IXFR) {
				fallback();
				doxfr();
				return;
			}
		}

		for (int i = 0; i < answers.length; i++) {
			parseRR(answers[i]);
		}

		if (state == END &&
		    response.tsigState == Message.TSIG_INTERMEDIATE)
			fail("last message must be signed");
	}
}

/**
 * Does the zone transfer.
 * @return A list, which is either an AXFR-style response (List of Records),
 * and IXFR-style response (List of Deltas), or null, which indicates that
 * an IXFR was performed and the zone is up to date.
 * @throws IOException The zone transfer failed to due an IO problem.
 * @throws ZoneTransferException The zone transfer failed to due a problem
 * with the zone transfer itself.
 */
public List
run() throws IOException, ZoneTransferException {
	openConnection();
	try {
		doxfr();
	}
	finally {
		closeConnection();
	}
	if (axfr != null)
		return axfr;
	return ixfr;
}

/**
 * Returns true if the response is an AXFR-style response (List of Records).
 * This will be true if either an IXFR was performed, an IXFR was performed
 * and the server provided a full zone transfer, or an IXFR failed and
 * fallback to AXFR occurred.
 */
public boolean
isAXFR() {
	return (rtype == Type.AXFR);
}

/**
 * Gets the AXFR-style response.
 */
public List
getAXFR() {
	return axfr;
}

/**
 * Returns true if the response is an IXFR-style response (List of Deltas).
 * This will be true only if an IXFR was performed and the server provided
 * an incremental zone transfer.
 */
public boolean
isIXFR() {
	return (rtype == Type.IXFR);
}

/**
 * Gets the IXFR-style response.
 */
public List
getIXFR() {
	return ixfr;
}

/**
 * Returns true if the response indicates that the zone is up to date.
 * This will be true only if an IXFR was performed.
 */
public boolean
isCurrent() {
	return (axfr == null && ixfr == null);
}

}