jdk-sandbox: comparison src/jdk.dns.client/share/classes/jdk/dns/client/internal/DnsClient.java

equal deleted inserted replaced

-:cc66ac8c7646
+:35c438a6d45c
+/*
+* Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+*
+* This code is free software; you can redistribute it and/or modify it
+* under the terms of the GNU General Public License version 2 only, as
+* published by the Free Software Foundation.  Oracle designates this
+* particular file as subject to the "Classpath" exception as provided
+* by Oracle in the LICENSE file that accompanied this code.
+*
+* This code is distributed in the hope that it will be useful, but WITHOUT
+* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+* version 2 for more details (a copy is included in the LICENSE file that
+* accompanied this code).
+*
+* You should have received a copy of the GNU General Public License version
+* 2 along with this work; if not, write to the Free Software Foundation,
+* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+*
+* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+* or visit www.oracle.com if you need additional information or have any
+* questions.
+*/
+package jdk.dns.client.internal;
+import jdk.dns.client.ex.DnsCommunicationException;
+import jdk.dns.client.ex.DnsNameNotFoundException;
+import jdk.dns.client.ex.DnsOperationNotSupportedException;
+import jdk.dns.client.ex.DnsResolverException;
+import jdk.dns.client.ex.DnsServiceUnavailableException;
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.Socket;
+import java.net.SocketTimeoutException;
+import java.net.UnknownHostException;
+import java.nio.ByteBuffer;
+import java.nio.channels.DatagramChannel;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.security.SecureRandom;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.locks.ReentrantLock;
+import sun.net.util.IPAddressUtil;
+import sun.security.jca.JCAUtil;
+// Some of this code began life as part of sun.javaos.net.DnsClient
+// originally by sritchie@eng 1/96.  It was first hacked up for JNDI
+// use by caveh@eng 6/97.
+/**
+* The DnsClient class performs DNS client operations in support of DnsContext.
+*/
+public class DnsClient {
+// DNS packet header field offsets
+private static final int IDENT_OFFSET = 0;
+private static final int FLAGS_OFFSET = 2;
+private static final int NUMQ_OFFSET = 4;
+private static final int NUMANS_OFFSET = 6;
+private static final int NUMAUTH_OFFSET = 8;
+private static final int NUMADD_OFFSET = 10;
+private static final int DNS_HDR_SIZE = 12;
+// DNS response codes
+private static final int NO_ERROR = 0;
+private static final int FORMAT_ERROR = 1;
+private static final int SERVER_FAILURE = 2;
+private static final int NAME_ERROR = 3;
+private static final int NOT_IMPL = 4;
+private static final int REFUSED = 5;
+private static final String[] rcodeDescription = {
+"No error",
+"DNS format error",
+"DNS server failure",
+"DNS name not found",
+"DNS operation not supported",
+"DNS service refused"
+};
+private static final int DEFAULT_PORT = 53;
+private static final int TRANSACTION_ID_BOUND = 0x10000;
+private List<InetAddress> servers;
+private List<Integer> serverPorts;
+private int timeout;                // initial timeout on UDP and TCP queries in ms
+private int retries;                // number of UDP retries
+private static final SecureRandom random;
+static {
+var pa = (PrivilegedAction<SecureRandom>) () -> JCAUtil.getSecureRandom();
+random = System.getSecurityManager() == null ? pa.run()
+: AccessController.doPrivileged(pa);
+}
+private static final DnsDatagramChannelFactory factory =
+new DnsDatagramChannelFactory(random);
+// Requests sent
+private Map<Integer, ResourceRecord> reqs;
+// Responses received
+private Map<Integer, byte[]> resps;
+//-------------------------------------------------------------------------
+/*
+* Each server is of the form "server[:port]".  IPv6 literal host names
+* include delimiting brackets.
+* "timeout" is the initial timeout interval (in ms) for queries,
+* and "retries" gives the number of retries per server.
+*/
+public DnsClient(List<String> servers, int timeout, int retries)
+throws UnknownHostException {
+this.timeout = timeout;
+this.retries = retries;
+var serversList = new ArrayList<InetAddress>();
+var serverPortsList = new ArrayList<Integer>();
+for (String serverString:servers) {
+// Is optional port given?
+int colon = serverString.indexOf(':',
+serverString.indexOf(']') + 1);
+int serverPort = (colon < 0) ? DEFAULT_PORT
+: Integer.parseInt(serverString.substring(colon + 1));
+String server = (colon < 0)
+? serverString
+: serverString.substring(0, colon);
+var pa = (PrivilegedAction<byte[]>) () -> {
+if (IPAddressUtil.isIPv4LiteralAddress(server)) {
+return IPAddressUtil.textToNumericFormatV4(server);
+} else if (IPAddressUtil.isIPv6LiteralAddress(server)) {
+return IPAddressUtil.textToNumericFormatV6(server);
+}
+return null;
+};
+byte[] addr = System.getSecurityManager() == null ?
+pa.run() : AccessController.doPrivileged(pa);
+if (addr != null) {
+serversList.add(InetAddress.getByAddress(server, addr));
+serverPortsList.add(serverPort);
+}
+}
+this.servers = Collections.unmodifiableList(serversList);
+this.serverPorts = Collections.unmodifiableList(serverPortsList);
+reqs = Collections.synchronizedMap(
+new HashMap<>());
+resps = Collections.synchronizedMap(new HashMap<>());
+}
+DatagramChannel getDatagramChannel() throws DnsResolverException {
+try {
+return factory.open();
+} catch (java.net.SocketException e) {
+throw new DnsResolverException("Can't create datagram channel", e);
+}
+}
+@SuppressWarnings("deprecation")
+protected void finalize() {
+close();
+}
+// A lock to access the request and response queues in tandem.
+private ReentrantLock queuesLock = new ReentrantLock();
+public void close() {
+queuesLock.lock();
+try {
+reqs.clear();
+resps.clear();
+} finally {
+queuesLock.unlock();
+}
+}
+/*
+* If recursion is true, recursion is requested on the query.
+* If auth is true, only authoritative responses are accepted; other
+* responses throw NameNotFoundException.
+*/
+ResourceRecords query(DnsName fqdn, int qclass, int qtype,
+boolean recursion, boolean auth)
+throws DnsResolverException {
+int xid;
+Packet pkt;
+ResourceRecord collision;
+do {
+// Generate a random transaction ID
+xid = random.nextInt(TRANSACTION_ID_BOUND);
+pkt = makeQueryPacket(fqdn, xid, qclass, qtype, recursion);
+// enqueue the outstanding request
+collision = reqs.putIfAbsent(xid, new ResourceRecord(pkt.getData(),
+pkt.length(), Header.HEADER_SIZE, true, false));
+} while (collision != null);
+Exception caughtException = null;
+boolean[] doNotRetry = new boolean[servers.size()];
+try {
+//
+// The UDP retry strategy is to try the 1st server, and then
+// each server in order. If no answer, double the timeout
+// and try each server again.
+//
+for (int retry = 0; retry < retries; retry++) {
+// Try each name server.
+for (int i = 0; i < servers.size(); i++) {
+if (doNotRetry[i]) {
+continue;
+}
+// send the request packet and wait for a response.
+try {
+if (DEBUG) {
+dprint("SEND ID (" + (retry + 1) + "): " + xid);
+}
+byte[] msg = doUdpQuery(pkt, servers.get(i), serverPorts.get(i), retry, xid);
+//
+// If the matching response is not got within the
+// given timeout, check if the response was enqueued
+// by some other thread, if not proceed with the next
+// server or retry.
+//
+if (msg == null) {
+if (resps.size() > 0) {
+msg = lookupResponse(xid);
+}
+if (msg == null) { // try next server or retry
+continue;
+}
+}
+Header hdr = new Header(msg, msg.length);
+if (auth && !hdr.authoritative) {
+caughtException = new DnsNameNotFoundException(
+"DNS response not authoritative");
+doNotRetry[i] = true;
+continue;
+}
+if (hdr.truncated) {  // message is truncated -- try TCP
+// Try each server, starting with the one that just
+// provided the truncated message.
+int retryTimeout = (timeout * (1 << retry));
+for (int j = 0; j < servers.size(); j++) {
+int ij = (i + j) % servers.size();
+if (doNotRetry[ij]) {
+continue;
+}
+try {
+Tcp tcp =
+new Tcp(servers.get(ij), serverPorts.get(ij), retryTimeout);
+byte[] msg2;
+try {
+msg2 = doTcpQuery(tcp, pkt);
+} finally {
+tcp.close();
+}
+Header hdr2 = new Header(msg2, msg2.length);
+if (hdr2.query) {
+throw new DnsCommunicationException(
+"DNS error: expecting response");
+}
+checkResponseCode(hdr2);
+if (!auth || hdr2.authoritative) {
+// Got a valid response
+hdr = hdr2;
+msg = msg2;
+break;
+} else {
+doNotRetry[ij] = true;
+}
+} catch (Exception e) {
+// Try next server, or use UDP response
+}
+} // servers
+}
+return new ResourceRecords(msg, msg.length, hdr, false);
+} catch (IOException e) {
+if (DEBUG) {
+dprint("Caught IOException:" + e);
+}
+if (caughtException == null) {
+caughtException = e;
+}
+// Use reflection to allow pre-1.4 compilation.
+// This won't be needed much longer.
+if (e.getClass().getName().equals(
+"java.net.PortUnreachableException")) {
+doNotRetry[i] = true;
+}
+// doNotRetry set - needs to be added
+} catch (DnsNameNotFoundException e) {
+// This is authoritative, so return immediately
+throw e;
+} catch (DnsCommunicationException e) {
+if (caughtException == null) {
+caughtException = e;
+}
+} catch (DnsResolverException e) {
+if (caughtException == null) {
+caughtException = e;
+}
+doNotRetry[i] = true;
+}
+} // servers
+} // retries
+} finally {
+reqs.remove(xid); // cleanup
+}
+if (caughtException instanceof DnsResolverException) {
+throw (DnsResolverException) caughtException;
+}
+// A network timeout or other error occurred.
+throw new DnsResolverException("DNS error", caughtException);
+}
+/**
+* Tries to retrieve a UDP packet matching the given xid
+* received within the timeout.
+* If a packet with different xid is received, the received packet
+* is enqueued with the corresponding xid in 'resps'.
+*/
+private byte[] doUdpQuery(Packet pkt, InetAddress server,
+int port, int retry, int xid)
+throws IOException, DnsResolverException {
+int minTimeout = 50; // msec after which there are no retries.
+try (DatagramChannel dc = getDatagramChannel()) {
+DatagramPacket opkt = new DatagramPacket(pkt.getData(), pkt.length(), server, port);
+DatagramPacket ipkt = new DatagramPacket(new byte[8000], 8000);
+// Packets may only be sent to or received from this server address
+// TODO: Revisit
+var pa = (PrivilegedAction<Void>) () -> {dc.socket().connect(server, port); return null;};
+if (System.getSecurityManager() == null) {
+pa.run();
+} else {
+AccessController.doPrivileged(pa);
+}
+int pktTimeout = (timeout * (1 << retry));
+try {
+dc.socket().send(opkt);
+// timeout remaining after successive 'receive()'
+int timeoutLeft = pktTimeout;
+int cnt = 0;
+do {
+if (DEBUG) {
+cnt++;
+dprint("Trying RECEIVE(" +
+cnt + ") retry(" + (retry + 1) +
+") for:" + xid + "    sock-timeout:" +
+timeoutLeft + " ms.");
+}
+dc.socket().setSoTimeout(timeoutLeft);
+long start = System.currentTimeMillis();
+byte[] data = ipkt.getData();
+ByteBuffer bb = ByteBuffer.wrap(data);
+dc.read(bb);
+long end = System.currentTimeMillis();
+if (isMatchResponse(data, xid)) {
+return data;
+}
+timeoutLeft = pktTimeout - ((int) (end - start));
+} while (timeoutLeft > minTimeout);
+} finally {
+dc.disconnect();
+}
+return null; // no matching packet received within the timeout
+}
+}
+/*
+* Sends a TCP query, and returns the first DNS message in the response.
+*/
+private byte[] doTcpQuery(Tcp tcp, Packet pkt) throws IOException {
+int len = pkt.length();
+// Send 2-byte message length, then send message.
+tcp.out.write(len >> 8);
+tcp.out.write(len);
+tcp.out.write(pkt.getData(), 0, len);
+tcp.out.flush();
+byte[] msg = continueTcpQuery(tcp);
+if (msg == null) {
+throw new IOException("DNS error: no response");
+}
+return msg;
+}
+/*
+* Returns the next DNS message from the TCP socket, or null on EOF.
+*/
+private byte[] continueTcpQuery(Tcp tcp) throws IOException {
+int lenHi = tcp.read();      // high-order byte of response length
+if (lenHi == -1) {
+return null;        // EOF
+}
+int lenLo = tcp.read();      // low-order byte of response length
+if (lenLo == -1) {
+throw new IOException("Corrupted DNS response: bad length");
+}
+int len = (lenHi << 8) | lenLo;
+byte[] msg = new byte[len];
+int pos = 0;                    // next unfilled position in msg
+while (len > 0) {
+int n = tcp.read(msg, pos, len);
+if (n == -1) {
+throw new IOException(
+"Corrupted DNS response: too little data");
+}
+len -= n;
+pos += n;
+}
+return msg;
+}
+private Packet makeQueryPacket(DnsName fqdn, int xid,
+int qclass, int qtype, boolean recursion) {
+int qnameLen = fqdn.getOctets();
+int pktLen = DNS_HDR_SIZE + qnameLen + 4;
+Packet pkt = new Packet(pktLen);
+short flags = recursion ? Header.RD_BIT : 0;
+pkt.putShort(xid, IDENT_OFFSET);
+pkt.putShort(flags, FLAGS_OFFSET);
+pkt.putShort(1, NUMQ_OFFSET);
+pkt.putShort(0, NUMANS_OFFSET);
+pkt.putInt(0, NUMAUTH_OFFSET);
+makeQueryName(fqdn, pkt, DNS_HDR_SIZE);
+pkt.putShort(qtype, DNS_HDR_SIZE + qnameLen);
+pkt.putShort(qclass, DNS_HDR_SIZE + qnameLen + 2);
+return pkt;
+}
+// Builds a query name in pkt according to the RFC spec.
+private void makeQueryName(DnsName fqdn, Packet pkt, int off) {
+// Loop through labels, least-significant first.
+for (int i = fqdn.size() - 1; i >= 0; i--) {
+String label = fqdn.get(i);
+int len = label.length();
+pkt.putByte(len, off++);
+for (int j = 0; j < len; j++) {
+pkt.putByte(label.charAt(j), off++);
+}
+}
+if (!fqdn.hasRootLabel()) {
+pkt.putByte(0, off);
+}
+}
+//-------------------------------------------------------------------------
+private byte[] lookupResponse(Integer xid) throws DnsResolverException {
+//
+// Check the queued responses: some other thread in between
+// received the response for this request.
+//
+if (DEBUG) {
+dprint("LOOKUP for: " + xid +
+"\tResponse Q:" + resps);
+}
+byte[] pkt;
+if ((pkt = resps.get(xid)) != null) {
+checkResponseCode(new Header(pkt, pkt.length));
+queuesLock.lock();
+try {
+resps.remove(xid);
+reqs.remove(xid);
+} finally {
+queuesLock.unlock();
+}
+if (DEBUG) {
+dprint("FOUND (" + Thread.currentThread() +
+") for:" + xid);
+}
+}
+return pkt;
+}
+/*
+* Checks the header of an incoming DNS response.
+* Returns true if it matches the given xid and throws a naming
+* exception, if appropriate, based on the response code.
+*
+* Also checks that the domain name, type and class in the response
+* match those in the original query.
+*/
+private boolean isMatchResponse(byte[] pkt, int xid)
+throws DnsResolverException {
+Header hdr = new Header(pkt, pkt.length);
+if (hdr.query) {
+throw new DnsCommunicationException("DNS error: expecting response");
+}
+if (!reqs.containsKey(xid)) { // already received, ignore the response
+return false;
+}
+// common case- the request sent matches the subsequent response read
+if (hdr.xid == xid) {
+if (DEBUG) {
+dprint("XID MATCH:" + xid);
+}
+checkResponseCode(hdr);
+if (!hdr.query && hdr.numQuestions == 1) {
+ResourceRecord rr = new ResourceRecord(pkt, pkt.length,
+Header.HEADER_SIZE, true, false);
+// Retrieve the original query
+ResourceRecord query = reqs.get(xid);
+int qtype = query.getType();
+int qclass = query.getRrclass();
+DnsName qname = query.getName();
+// Check that the type/class/name in the query section of the
+// response match those in the original query
+if ((qtype == ResourceRecord.QTYPE_STAR ||
+qtype == rr.getType()) &&
+(qclass == ResourceRecord.QCLASS_STAR ||
+qclass == rr.getRrclass()) &&
+qname.equals(rr.getName())) {
+if (DEBUG) {
+dprint("MATCH NAME:" + qname + " QTYPE:" + qtype +
+" QCLASS:" + qclass);
+}
+// Remove the response for the xid if received by some other
+// thread.
+queuesLock.lock();
+try {
+resps.remove(xid);
+reqs.remove(xid);
+} finally {
+queuesLock.unlock();
+}
+return true;
+} else {
+if (DEBUG) {
+dprint("NO-MATCH NAME:" + qname + " QTYPE:" + qtype +
+" QCLASS:" + qclass);
+}
+}
+}
+return false;
+}
+//
+// xid mis-match: enqueue the response, it may belong to some other
+// thread that has not yet had a chance to read its response.
+// enqueue only the first response, responses for retries are ignored.
+//
+queuesLock.lock();
+try {
+if (reqs.containsKey(hdr.xid)) { // enqueue only the first response
+resps.put(hdr.xid, pkt);
+}
+} finally {
+queuesLock.unlock();
+}
+if (DEBUG) {
+dprint("NO-MATCH SEND ID:" +
+xid + " RECVD ID:" + hdr.xid +
+"    Response Q:" + resps +
+"    Reqs size:" + reqs.size());
+}
+return false;
+}
+/*
+* Throws an exception if appropriate for the response code of a
+* given header.
+*/
+private void checkResponseCode(Header hdr) throws DnsResolverException {
+int rcode = hdr.rcode;
+if (rcode == NO_ERROR) {
+return;
+}
+String msg = (rcode < rcodeDescription.length)
+? rcodeDescription[rcode]
+: "DNS error";
+msg += " [response code " + rcode + "]";
+switch (rcode) {
+case SERVER_FAILURE:
+throw new DnsServiceUnavailableException(msg);
+case NAME_ERROR:
+throw new DnsNameNotFoundException(msg);
+case NOT_IMPL:
+case REFUSED:
+throw new DnsOperationNotSupportedException(msg);
+case FORMAT_ERROR:
+default:
+throw new DnsResolverException(msg);
+}
+}
+//-------------------------------------------------------------------------
+private static final boolean DEBUG = java.security.AccessController.doPrivileged(
+(PrivilegedAction<Boolean>) () -> Boolean.getBoolean("jdk.dns.client.debug"));
+private static void dprint(String mess) {
+if (DEBUG) {
+System.err.println("DNS: " + mess);
+}
+}
+}
+class Tcp {
+private final Socket sock;
+private final java.io.InputStream in;
+final java.io.OutputStream out;
+private int timeoutLeft;
+Tcp(InetAddress server, int port, int timeout) throws IOException {
+sock = new Socket();
+try {
+long start = System.currentTimeMillis();
+sock.connect(new InetSocketAddress(server, port), timeout);
+timeoutLeft = (int) (timeout - (System.currentTimeMillis() - start));
+if (timeoutLeft <= 0)
+throw new SocketTimeoutException();
+sock.setTcpNoDelay(true);
+out = new java.io.BufferedOutputStream(sock.getOutputStream());
+in = new java.io.BufferedInputStream(sock.getInputStream());
+} catch (Exception e) {
+try {
+sock.close();
+} catch (IOException ex) {
+e.addSuppressed(ex);
+}
+throw e;
+}
+}
+void close() throws IOException {
+sock.close();
+}
+private interface SocketReadOp {
+int read() throws IOException;
+}
+private int readWithTimeout(SocketReadOp reader) throws IOException {
+if (timeoutLeft <= 0)
+throw new SocketTimeoutException();
+sock.setSoTimeout(timeoutLeft);
+long start = System.currentTimeMillis();
+try {
+return reader.read();
+} finally {
+timeoutLeft -= System.currentTimeMillis() - start;
+}
+}
+int read() throws IOException {
+return readWithTimeout(in::read);
+}
+int read(byte b[], int off, int len) throws IOException {
+return readWithTimeout(() -> in.read(b, off, len));
+}
+}
+/*
+* javaos emulation -cj
+*/
+class Packet {
+byte[] buf;
+Packet(int len) {
+buf = new byte[len];
+}
+Packet(byte data[], int len) {
+buf = new byte[len];
+System.arraycopy(data, 0, buf, 0, len);
+}
+void putInt(int x, int off) {
+buf[off] = (byte) (x >> 24);
+buf[off + 1] = (byte) (x >> 16);
+buf[off + 2] = (byte) (x >> 8);
+buf[off + 3] = (byte) x;
+}
+void putShort(int x, int off) {
+buf[off] = (byte) (x >> 8);
+buf[off + 1] = (byte) x;
+}
+void putByte(int x, int off) {
+buf[off] = (byte) x;
+}
+void putBytes(byte src[], int src_offset, int dst_offset, int len) {
+System.arraycopy(src, src_offset, buf, dst_offset, len);
+}
+int length() {
+return buf.length;
+}
+byte[] getData() {
+return buf;
+}
+}

branch	aefimov-dns-client-branch
changeset 58870	35c438a6d45c
child 58971	465a15dd6bed