dnsjava/src/main/java/org/xbill/DNS/SimpleResolver.java at master · dnsjava/dnsjava · GitHub

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// SPDX-License-Identifier: BSD-3-Clause

package org.xbill.DNS;

import java.io.IOException;

import java.net.InetAddress;

import java.net.InetSocketAddress;

import java.net.UnknownHostException;

import java.time.Duration;

import java.util.List;

import java.util.Objects;

import java.util.concurrent.CompletableFuture;

import java.util.concurrent.CompletionStage;

import java.util.concurrent.Executor;

import java.util.concurrent.ForkJoinPool;

import lombok.Getter;

import lombok.Setter;

import lombok.extern.slf4j.Slf4j;

import org.xbill.DNS.io.DefaultIoClientFactory;

import org.xbill.DNS.io.IoClientFactory;

/**

* An implementation of Resolver that sends one query to one server. SimpleResolver handles TCP

* retries, transaction security (TSIG), and EDNS 0.

* @see Resolver

* @see TSIG

* @see OPTRecord

* @author Brian Wellington

@Slf4j

public class SimpleResolver implements Resolver {

/** The default port to send queries to */

public static final int DEFAULT_PORT = 53;

/** The default EDNS payload size */

public static final int DEFAULT_EDNS_PAYLOADSIZE = 1280;

private InetSocketAddress address;

private InetSocketAddress localAddress;

private boolean useTCP;

private boolean ignoreTruncation;

private OPTRecord queryOPT = new OPTRecord(DEFAULT_EDNS_PAYLOADSIZE, 0, 0, 0);

private TSIG tsig;

private Duration timeoutValue = Duration.ofSeconds(10);

private static final short DEFAULT_UDPSIZE = 512;

/**

* Gets or sets the factory that creates clients for sending messages to the wire.

* @since 3.6

@Getter @Setter private IoClientFactory ioClientFactory = new DefaultIoClientFactory();

private static InetSocketAddress defaultResolver =

new InetSocketAddress(InetAddress.getLoopbackAddress(), DEFAULT_PORT);

/**

* Creates a SimpleResolver. The host to query is either found by using ResolverConfig, or the

* default host is used.

* @see ResolverConfig

* @exception UnknownHostException Failure occurred while finding the host

public SimpleResolver() throws UnknownHostException {

this((String) null);

}

/**

* Creates a SimpleResolver that will query the specified host

* @exception UnknownHostException Failure occurred while finding the host

public SimpleResolver(String hostname) throws UnknownHostException {

if (hostname == null) {

address = ResolverConfig.getCurrentConfig().server();

if (address == null) {

address = defaultResolver;

}

return;

}

InetAddress addr;

if ("0".equals(hostname)) {

addr = InetAddress.getLoopbackAddress();

} else {

addr = InetAddress.getByName(hostname);

}

address = new InetSocketAddress(addr, DEFAULT_PORT);

}

/** Creates a SimpleResolver that will query the specified host */

public SimpleResolver(InetSocketAddress host) {

address = Objects.requireNonNull(host, "host must not be null");

}

/** Creates a SimpleResolver that will query the specified host */

public SimpleResolver(InetAddress host) {

Objects.requireNonNull(host, "host must not be null");

address = new InetSocketAddress(host, DEFAULT_PORT);

}

/**

* Gets the destination address associated with this SimpleResolver. Messages sent using this

* SimpleResolver will be sent to this address.

* @return The destination address associated with this SimpleResolver.

public InetSocketAddress getAddress() {

return address;

}

/** Sets the default host (initially localhost) to query */

public static void setDefaultResolver(InetSocketAddress hostname) {

defaultResolver = hostname;

}

/** Sets the default host (initially localhost) to query */

public static void setDefaultResolver(String hostname) {

defaultResolver = new InetSocketAddress(hostname, DEFAULT_PORT);

}

/**

* Gets the port to communicate with on the server

* @since 3.2

public int getPort() {

return address.getPort();

}

@Override

public void setPort(int port) {

address = new InetSocketAddress(address.getAddress(), port);

}

/**

* Sets the address of the server to communicate with.

* @param addr The address of the DNS server

public void setAddress(InetSocketAddress addr) {

address = addr;

}

/**

* Sets the address of the server to communicate with (on the default DNS port)

* @param addr The address of the DNS server

public void setAddress(InetAddress addr) {

address = new InetSocketAddress(addr, address.getPort());

}

/**

* Sets the local address to bind to when sending messages.

* @param addr The local address to send messages from.

public void setLocalAddress(InetSocketAddress addr) {

localAddress = addr;

}

/**

* Sets the local address to bind to when sending messages. A random port will be used.

* @param addr The local address to send messages from.

public void setLocalAddress(InetAddress addr) {

localAddress = new InetSocketAddress(addr, 0);

}

/**

* Gets whether TCP connections will be used by default

* @since 3.2

public boolean getTCP() {

return useTCP;

}

@Override

public void setTCP(boolean flag) {

this.useTCP = flag;

}

/**

* Gets whether truncated responses will be ignored.

* @since 3.2

public boolean getIgnoreTruncation() {

return ignoreTruncation;

}

@Override

public void setIgnoreTruncation(boolean flag) {

this.ignoreTruncation = flag;

}

/**

* Gets the EDNS information on outgoing messages.

* @return The current {@link OPTRecord} for EDNS or {@code null} if EDNS is disabled.

* @since 3.2

public OPTRecord getEDNS() {

return queryOPT;

}

/**

* Sets the EDNS information on outgoing messages.

* @param optRecord the {@link OPTRecord} for EDNS options or null to disable EDNS.

* @see #setEDNS(int, int, int, List)

* @since 3.2

public void setEDNS(OPTRecord optRecord) {

queryOPT = optRecord;

}

@Override

public void setEDNS(int version, int payloadSize, int flags, List<EDNSOption> options) {

switch (version) {

case -1:

queryOPT = null;

break;

case 0:

if (payloadSize == 0) {

payloadSize = DEFAULT_EDNS_PAYLOADSIZE;

}

queryOPT = new OPTRecord(payloadSize, 0, version, flags, options);

break;

default:

throw new IllegalArgumentException("invalid EDNS version - must be 0 or -1 to disable");

}

/**

* Get the TSIG key that messages will be signed with.

* @return the TSIG signature for outgoing messages or {@code null} if not specified.

* @since 3.2

public TSIG getTSIGKey() {

return tsig;

}

@Override

public void setTSIGKey(TSIG key) {

tsig = key;

}

@Override

public void setTimeout(Duration timeout) {

timeoutValue = timeout;

}

@Override

public Duration getTimeout() {

return timeoutValue;

}

private Message parseMessage(byte[] b) throws WireParseException {

try {

return new Message(b);

} catch (IOException e) {

if (!(e instanceof WireParseException)) {

throw new WireParseException("Error parsing message", e);

}

throw (WireParseException) e;

}

private void verifyTSIG(Message query, Message response, byte[] b) {

if (tsig == null) {

return;

}

int error = tsig.verify(response, b, query.getGeneratedTSIG());

log.debug(

"TSIG verify on message id {}: {}", query.getHeader().getID(), Rcode.TSIGstring(error));

}

private void applyEDNS(Message query) {

if (queryOPT == null || query.getOPT() != null) {

return;

}

query.addRecord(queryOPT, Section.ADDITIONAL);

}

private int maxUDPSize(Message query) {

OPTRecord opt = query.getOPT();

if (opt == null) {

return DEFAULT_UDPSIZE;

} else {

return opt.getPayloadSize();

}

/**

* Asynchronously sends a message to a single server.

* @param query The query to send

* @return A future that completes when the response has arrived.

@Override

public CompletionStage<Message> sendAsync(Message query) {

return sendAsync(query, ForkJoinPool.commonPool());

}

/**

* Asynchronously sends a message to a single server.

* @param query The query to send

* @param executor The service to use for async operations.

* @return A future that completes when the response has arrived.

@Override

public CompletionStage<Message> sendAsync(Message query, Executor executor) {

if (query.getHeader().getOpcode() == Opcode.QUERY) {

Record question = query.getQuestion();

if (question != null && question.getType() == Type.AXFR) {

CompletableFuture<Message> f = new CompletableFuture<>();

CompletableFuture.runAsync(

() -> {

try {

f.complete(sendAXFR(query));

} catch (IOException e) {

f.completeExceptionally(e);

}

executor);

return f;

}

Message ednsTsigQuery = query.clone();

applyEDNS(ednsTsigQuery);

if (tsig != null) {

ednsTsigQuery.setTSIG(tsig, Rcode.NOERROR, null);

}

return sendAsync(ednsTsigQuery, useTCP, executor);

}

CompletableFuture<Message> sendAsync(Message query, boolean forceTcp, Executor executor) {

int qid = query.getHeader().getID();

boolean truncate = query.getHeader().getOpcode() != Opcode.UPDATE;

byte[] out;

try {

out = query.toWire(Message.MAXLENGTH, truncate);

} catch (MessageSizeExceededException e) {

CompletableFuture<Message> f = new CompletableFuture<>();

f.completeExceptionally(e);

return f;

}

int udpSize = maxUDPSize(query);

boolean tcp = forceTcp || out.length > udpSize;

if (log.isTraceEnabled()) {

log.trace(

"Sending {}/{}, id={} to {}/{}:{}, query:\n{}",

query.getQuestion().getName(),

Type.string(query.getQuestion().getType()),

qid,

tcp ? "tcp" : "udp",

address.getAddress().getHostAddress(),

address.getPort(),

query);

} else if (log.isDebugEnabled()) {

log.debug(

"Sending {}/{}, id={} to {}/{}:{}",

query.getQuestion().getName(),

Type.string(query.getQuestion().getType()),

qid,

tcp ? "tcp" : "udp",

address.getAddress().getHostAddress(),

address.getPort());

}

CompletableFuture<byte[]> result;

if (tcp) {

result =

ioClientFactory

.createOrGetTcpClient()

.sendAndReceiveTcp(localAddress, address, query, out, timeoutValue);

} else {

result =

ioClientFactory

.createOrGetUdpClient()

.sendAndReceiveUdp(localAddress, address, query, out, udpSize, timeoutValue);

}

return result.thenComposeAsync(

in -> {

CompletableFuture<Message> f = new CompletableFuture<>();

// Check that the response is long enough.

if (in.length < Header.LENGTH) {

f.completeExceptionally(new WireParseException("invalid DNS header - too short"));

return f;

}

// Check that the response ID matches the query ID. We want

// to check this before actually parsing the message, so that

// if there's a malformed response that's not ours, it

// doesn't confuse us.

int id = ((in[0] & 0xFF) << 8) + (in[1] & 0xFF);

if (id != qid) {

f.completeExceptionally(

new WireParseException("invalid message id: expected " + qid + "; got id " + id));

return f;

}

Message response;

try {

response = parseMessage(in);

} catch (WireParseException e) {

f.completeExceptionally(e);

return f;

}

// rfc2136#section-3.8:

// A response message is generated by copying the ID and Opcode fields from the request,

// [...] and not including any part of the original update

if (query.getHeader().getOpcode() == Opcode.UPDATE) {

if (response.getHeader().getOpcode() != Opcode.UPDATE) {

f.completeExceptionally(

new WireParseException("invalid message: opcode response is not UPDATE"));

return f;

}

} else {

if (response.getQuestion() == null) {

f.completeExceptionally(

new WireParseException("invalid message: question section missing"));

return f;

}

// validate name, class and type (rfc5452#section-9.1)

if (!query.getQuestion().getName().equals(response.getQuestion().getName())) {

f.completeExceptionally(

new WireParseException(

"invalid name in message: expected "

+ query.getQuestion().getName()

+ "; got "

+ response.getQuestion().getName()));

return f;

}

if (query.getQuestion().getDClass() != response.getQuestion().getDClass()) {

f.completeExceptionally(

new WireParseException(

"invalid class in message: expected "

+ DClass.string(query.getQuestion().getDClass())

+ "; got "

+ DClass.string(response.getQuestion().getDClass())));

return f;

}

if (query.getQuestion().getType() != response.getQuestion().getType()) {

f.completeExceptionally(

new WireParseException(

"invalid type in message: expected "

+ Type.string(query.getQuestion().getType())

+ "; got "

+ Type.string(response.getQuestion().getType())));

return f;

}

verifyTSIG(query, response, in);

if (!tcp && !ignoreTruncation && response.getHeader().getFlag(Flags.TC)) {

if (log.isTraceEnabled()) {

log.trace(

"Got truncated response for id {}, retrying via TCP, response:\n{}",

qid,

response);

} else {

log.debug("Got truncated response for id {}, retrying via TCP", qid);

}

return sendAsync(query, true, executor);

}

response.setResolver(this);

f.complete(response);

return f;

executor);

}

private Message sendAXFR(Message query) throws IOException {

Name qname = query.getQuestion().getName();

ZoneTransferIn xfrin = ZoneTransferIn.newAXFR(qname, address, tsig);

xfrin.setTimeout(timeoutValue);

xfrin.setLocalAddress(localAddress);

try {

xfrin.run();

} catch (ZoneTransferException e) {

throw new WireParseException(e.getMessage());

}

List<Record> records = xfrin.getAXFR();

Message response = new Message(query.getHeader().getID());

response.getHeader().setFlag(Flags.AA);

response.getHeader().setFlag(Flags.QR);

response.addRecord(query.getQuestion(), Section.QUESTION);

for (Record r : records) {

response.addRecord(r, Section.ANSWER);

}

return response;

}

@Override

public String toString() {

return "SimpleResolver [" + address + "]";

}

dnsjava/src/main/java/org/xbill/DNS/SimpleResolver.java at master · dnsjava/dnsjava · GitHub

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