org.apache.hadoop.net.NetUtils.java Source code

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.hadoop.net;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.NetworkInterface;
import java.net.Socket;
import java.net.SocketAddress;
import java.net.SocketException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.UnknownHostException;
import java.net.ConnectException;
import java.nio.channels.SocketChannel;
import java.util.Map.Entry;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;

import javax.net.SocketFactory;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.ipc.Server;
import org.apache.hadoop.ipc.VersionedProtocol;
import org.apache.hadoop.security.SecurityUtil;
import org.apache.hadoop.util.ReflectionUtils;

public class NetUtils {
    private static final Log LOG = LogFactory.getLog(NetUtils.class);

    private static Map<String, String> hostToResolved = new HashMap<String, String>();

    /**
     * Get the socket factory for the given class according to its
     * configuration parameter
     * <tt>hadoop.rpc.socket.factory.class.&lt;ClassName&gt;</tt>. When no
     * such parameter exists then fall back on the default socket factory as
     * configured by <tt>hadoop.rpc.socket.factory.class.default</tt>. If
     * this default socket factory is not configured, then fall back on the JVM
     * default socket factory.
     * 
     * @param conf the configuration
     * @param clazz the class (usually a {@link VersionedProtocol})
     * @return a socket factory
     */
    public static SocketFactory getSocketFactory(Configuration conf, Class<?> clazz) {

        SocketFactory factory = null;

        String propValue = conf.get("hadoop.rpc.socket.factory.class." + clazz.getSimpleName());
        if ((propValue != null) && (propValue.length() > 0))
            factory = getSocketFactoryFromProperty(conf, propValue);

        if (factory == null)
            factory = getDefaultSocketFactory(conf);

        return factory;
    }

    /**
     * Get the default socket factory as specified by the configuration
     * parameter <tt>hadoop.rpc.socket.factory.default</tt>
     * 
     * @param conf the configuration
     * @return the default socket factory as specified in the configuration or
     *         the JVM default socket factory if the configuration does not
     *         contain a default socket factory property.
     */
    public static SocketFactory getDefaultSocketFactory(Configuration conf) {

        String propValue = conf.get("hadoop.rpc.socket.factory.class.default");
        if ((propValue == null) || (propValue.length() == 0))
            return SocketFactory.getDefault();

        return getSocketFactoryFromProperty(conf, propValue);
    }

    /**
     * Get the socket factory corresponding to the given proxy URI. If the
     * given proxy URI corresponds to an absence of configuration parameter,
     * returns null. If the URI is malformed raises an exception.
     * 
     * @param propValue the property which is the class name of the
     *        SocketFactory to instantiate; assumed non null and non empty.
     * @return a socket factory as defined in the property value.
     */
    public static SocketFactory getSocketFactoryFromProperty(Configuration conf, String propValue) {

        try {
            Class<?> theClass = conf.getClassByName(propValue);
            return (SocketFactory) ReflectionUtils.newInstance(theClass, conf);

        } catch (ClassNotFoundException cnfe) {
            throw new RuntimeException("Socket Factory class not found: " + cnfe);
        }
    }

    /**
     * Util method to build socket addr from either:
     *   <host>:<post>
     *   <fs>://<host>:<port>/<path>
     */
    public static InetSocketAddress createSocketAddr(String target) {
        return createSocketAddr(target, -1);
    }

    /**
     * Util method to build socket addr from either:
     *   <host>
     *   <host>:<post>
     *   <fs>://<host>:<port>/<path>
     */
    public static InetSocketAddress createSocketAddr(String target, int defaultPort) {
        if (target == null) {
            throw new IllegalArgumentException("Socket address is null");
        }
        boolean hasScheme = target.contains("://");
        URI uri = null;
        try {
            uri = hasScheme ? URI.create(target) : URI.create("dummyscheme://" + target);
        } catch (IllegalArgumentException e) {
            throw new IllegalArgumentException("Does not contain a valid host:port authority: " + target);
        }

        String host = uri.getHost();
        int port = uri.getPort();
        if (port == -1) {
            port = defaultPort;
        }
        String path = uri.getPath();

        if ((host == null) || (port < 0) || (!hasScheme && path != null && !path.isEmpty())) {
            throw new IllegalArgumentException("Does not contain a valid host:port authority: " + target);
        }
        return makeSocketAddr(host, port);
    }

    /**
     * Create a socket address with the given host and port.  The hostname
     * might be replaced with another host that was set via
     * {@link #addStaticResolution(String, String)}.  The value of
     * hadoop.security.token.service.use_ip will determine whether the
     * standard java host resolver is used, or if the fully qualified resolver
     * is used.
     * @param host the hostname or IP use to instantiate the object
     * @param port the port number
     * @return InetSocketAddress
     */
    public static InetSocketAddress makeSocketAddr(String host, int port) {
        String staticHost = getStaticResolution(host);
        String resolveHost = (staticHost != null) ? staticHost : host;

        InetSocketAddress addr;
        try {
            InetAddress iaddr = SecurityUtil.getByName(resolveHost);
            // if there is a static entry for the host, make the returned
            // address look like the original given host
            if (staticHost != null) {
                iaddr = InetAddress.getByAddress(host, iaddr.getAddress());
            }
            addr = new InetSocketAddress(iaddr, port);
        } catch (UnknownHostException e) {
            addr = InetSocketAddress.createUnresolved(host, port);
        }
        return addr;
    }

    /**
     * Resolve the uri's hostname and add the default port if not in the uri
     * @param uri to resolve
     * @param defaultPort if none is given
     * @return URI
     * @throws UnknownHostException 
     */
    public static URI getCanonicalUri(URI uri, int defaultPort) {
        // skip if there is no authority, ie. "file" scheme or relative uri
        String host = uri.getHost();
        if (host == null) {
            return uri;
        }
        String fqHost = canonicalizeHost(host);
        int port = uri.getPort();
        // short out if already canonical with a port
        if (host.equals(fqHost) && port != -1) {
            return uri;
        }
        // reconstruct the uri with the canonical host and port
        try {
            uri = new URI(uri.getScheme(), uri.getUserInfo(), fqHost, (port == -1) ? defaultPort : port,
                    uri.getPath(), uri.getQuery(), uri.getFragment());
        } catch (URISyntaxException e) {
            throw new IllegalArgumentException(e);
        }
        return uri;
    }

    // cache the canonicalized hostnames;  the cache currently isn't expired,
    // but the canonicals will only change if the host's resolver configuration
    // changes
    private static ConcurrentHashMap<String, String> canonicalizedHostCache = new ConcurrentHashMap<String, String>();

    private static String canonicalizeHost(String host) {
        // check if the host has already been canonicalized
        String fqHost = canonicalizedHostCache.get(host);
        if (fqHost == null) {
            try {
                fqHost = SecurityUtil.getByName(host).getHostName();
                // slight race condition, but won't hurt 
                canonicalizedHostCache.put(host, fqHost);
            } catch (UnknownHostException e) {
                fqHost = host;
            }
        }
        return fqHost;
    }

    /**
     * Handle the transition from pairs of attributes specifying a host and port
     * to a single colon separated one.
     * @param conf the configuration to check
     * @param oldBindAddressName the old address attribute name
     * @param oldPortName the old port attribute name
     * @param newBindAddressName the new combined name
     * @return the complete address from the configuration
     */
    @Deprecated
    public static String getServerAddress(Configuration conf, String oldBindAddressName, String oldPortName,
            String newBindAddressName) {
        String oldAddr = conf.get(oldBindAddressName);
        String oldPort = conf.get(oldPortName);
        String newAddrPort = conf.get(newBindAddressName);
        if (oldAddr == null && oldPort == null) {
            return newAddrPort;
        }
        String[] newAddrPortParts = newAddrPort.split(":", 2);
        if (newAddrPortParts.length != 2) {
            throw new IllegalArgumentException("Invalid address/port: " + newAddrPort);
        }
        if (oldAddr == null) {
            oldAddr = newAddrPortParts[0];
        } else {
            LOG.warn("Configuration parameter " + oldBindAddressName + " is deprecated. Use " + newBindAddressName
                    + " instead.");
        }
        if (oldPort == null) {
            oldPort = newAddrPortParts[1];
        } else {
            LOG.warn("Configuration parameter " + oldPortName + " is deprecated. Use " + newBindAddressName
                    + " instead.");
        }
        return oldAddr + ":" + oldPort;
    }

    /**
     * Adds a static resolution for host. This can be used for setting up
     * hostnames with names that are fake to point to a well known host. For e.g.
     * in some testcases we require to have daemons with different hostnames
     * running on the same machine. In order to create connections to these
     * daemons, one can set up mappings from those hostnames to "localhost".
     * {@link NetUtils#getStaticResolution(String)} can be used to query for
     * the actual hostname. 
     * @param host
     * @param resolvedName
     */
    public static void addStaticResolution(String host, String resolvedName) {
        synchronized (hostToResolved) {
            hostToResolved.put(host, resolvedName);
        }
    }

    /**
     * Retrieves the resolved name for the passed host. The resolved name must
     * have been set earlier using 
     * {@link NetUtils#addStaticResolution(String, String)}
     * @param host
     * @return the resolution
     */
    public static String getStaticResolution(String host) {
        synchronized (hostToResolved) {
            return hostToResolved.get(host);
        }
    }

    /**
     * This is used to get all the resolutions that were added using
     * {@link NetUtils#addStaticResolution(String, String)}. The return
     * value is a List each element of which contains an array of String 
     * of the form String[0]=hostname, String[1]=resolved-hostname
     * @return the list of resolutions
     */
    public static List<String[]> getAllStaticResolutions() {
        synchronized (hostToResolved) {
            Set<Entry<String, String>> entries = hostToResolved.entrySet();
            if (entries.size() == 0) {
                return null;
            }
            List<String[]> l = new ArrayList<String[]>(entries.size());
            for (Entry<String, String> e : entries) {
                l.add(new String[] { e.getKey(), e.getValue() });
            }
            return l;
        }
    }

    /**
     * Returns InetSocketAddress that a client can use to 
     * connect to the server. Server.getListenerAddress() is not correct when
     * the server binds to "0.0.0.0". This returns "127.0.0.1:port" when
     * the getListenerAddress() returns "0.0.0.0:port".
     * 
     * @param server
     * @return socket address that a client can use to connect to the server.
     */
    public static InetSocketAddress getConnectAddress(Server server) {
        InetSocketAddress addr = server.getListenerAddress();
        if (addr.getAddress().isAnyLocalAddress()) {
            addr = makeSocketAddr("127.0.0.1", addr.getPort());
        }
        return addr;
    }

    /**
     * Same as getInputStream(socket, socket.getSoTimeout()).<br><br>
     * 
     * From documentation for {@link #getInputStream(Socket, long)}:<br>
     * Returns InputStream for the socket. If the socket has an associated
     * SocketChannel then it returns a 
     * {@link SocketInputStream} with the given timeout. If the socket does not
     * have a channel, {@link Socket#getInputStream()} is returned. In the later
     * case, the timeout argument is ignored and the timeout set with 
     * {@link Socket#setSoTimeout(int)} applies for reads.<br><br>
     *
     * Any socket created using socket factories returned by {@link NetUtils},
     * must use this interface instead of {@link Socket#getInputStream()}.
     *     
     * @see #getInputStream(Socket, long)
     * 
     * @param socket
     * @return InputStream for reading from the socket.
     * @throws IOException
     */
    public static InputStream getInputStream(Socket socket) throws IOException {
        return getInputStream(socket, socket.getSoTimeout());
    }

    /**
     * Returns InputStream for the socket. If the socket has an associated
     * SocketChannel then it returns a 
     * {@link SocketInputStream} with the given timeout. If the socket does not
     * have a channel, {@link Socket#getInputStream()} is returned. In the later
     * case, the timeout argument is ignored and the timeout set with 
     * {@link Socket#setSoTimeout(int)} applies for reads.<br><br>
     * 
     * Any socket created using socket factories returned by {@link NetUtils},
     * must use this interface instead of {@link Socket#getInputStream()}.
     *     
     * @see Socket#getChannel()
     * 
     * @param socket
     * @param timeout timeout in milliseconds. This may not always apply. zero
     *        for waiting as long as necessary.
     * @return InputStream for reading from the socket.
     * @throws IOException
     */
    public static InputStream getInputStream(Socket socket, long timeout) throws IOException {
        return (socket.getChannel() == null) ? socket.getInputStream() : new SocketInputStream(socket, timeout);
    }

    /**
     * Same as getOutputStream(socket, 0). Timeout of zero implies write will
     * wait until data is available.<br><br>
     * 
     * From documentation for {@link #getOutputStream(Socket, long)} : <br>
     * Returns OutputStream for the socket. If the socket has an associated
     * SocketChannel then it returns a 
     * {@link SocketOutputStream} with the given timeout. If the socket does not
     * have a channel, {@link Socket#getOutputStream()} is returned. In the later
     * case, the timeout argument is ignored and the write will wait until 
     * data is available.<br><br>
     * 
     * Any socket created using socket factories returned by {@link NetUtils},
     * must use this interface instead of {@link Socket#getOutputStream()}.
     * 
     * @see #getOutputStream(Socket, long)
     * 
     * @param socket
     * @return OutputStream for writing to the socket.
     * @throws IOException
     */
    public static OutputStream getOutputStream(Socket socket) throws IOException {
        return getOutputStream(socket, 0);
    }

    /**
     * Returns OutputStream for the socket. If the socket has an associated
     * SocketChannel then it returns a 
     * {@link SocketOutputStream} with the given timeout. If the socket does not
     * have a channel, {@link Socket#getOutputStream()} is returned. In the later
     * case, the timeout argument is ignored and the write will wait until 
     * data is available.<br><br>
     * 
     * Any socket created using socket factories returned by {@link NetUtils},
     * must use this interface instead of {@link Socket#getOutputStream()}.
     * 
     * @see Socket#getChannel()
     * 
     * @param socket
     * @param timeout timeout in milliseconds. This may not always apply. zero
     *        for waiting as long as necessary.
     * @return OutputStream for writing to the socket.
     * @throws IOException   
     */
    public static OutputStream getOutputStream(Socket socket, long timeout) throws IOException {
        return (socket.getChannel() == null) ? socket.getOutputStream() : new SocketOutputStream(socket, timeout);
    }

    /**
     * This is a drop-in replacement for 
     * {@link Socket#connect(SocketAddress, int)}.
     * In the case of normal sockets that don't have associated channels, this 
     * just invokes <code>socket.connect(endpoint, timeout)</code>. If 
     * <code>socket.getChannel()</code> returns a non-null channel,
     * connect is implemented using Hadoop's selectors. This is done mainly
     * to avoid Sun's connect implementation from creating thread-local 
     * selectors, since Hadoop does not have control on when these are closed
     * and could end up taking all the available file descriptors.
     * 
     * @see java.net.Socket#connect(java.net.SocketAddress, int)
     * 
     * @param socket
     * @param endpoint 
     * @param timeout - timeout in milliseconds
     */
    public static void connect(Socket socket, SocketAddress endpoint, int timeout) throws IOException {
        if (socket == null || endpoint == null || timeout < 0) {
            throw new IllegalArgumentException("Illegal argument for connect()");
        }

        SocketChannel ch = socket.getChannel();

        if (ch == null) {
            // let the default implementation handle it.
            socket.connect(endpoint, timeout);
        } else {
            SocketIOWithTimeout.connect(ch, endpoint, timeout);
        }

        // There is a very rare case allowed by the TCP specification, such that
        // if we are trying to connect to an endpoint on the local machine,
        // and we end up choosing an ephemeral port equal to the destination port,
        // we will actually end up getting connected to ourself (ie any data we
        // send just comes right back). This is only possible if the target
        // daemon is down, so we'll treat it like connection refused.
        if (socket.getLocalPort() == socket.getPort() && socket.getLocalAddress().equals(socket.getInetAddress())) {
            LOG.info("Detected a loopback TCP socket, disconnecting it");
            socket.close();
            throw new ConnectException("Localhost targeted connection resulted in a loopback. "
                    + "No daemon is listening on the target port.");
        }
    }

    /** 
     * Given a string representation of a host, return its ip address
     * in textual presentation.
     * 
     * @param name a string representation of a host:
     *             either a textual representation its IP address or its host name
     * @return its IP address in the string format
     */
    public static String normalizeHostName(String name) {
        if (Character.digit(name.charAt(0), 10) != -1) { //FIXME 
            return name;
        } else {
            try {
                InetAddress ipAddress = InetAddress.getByName(name);
                return ipAddress.getHostAddress();
            } catch (UnknownHostException e) {
                return name;
            }
        }
    }

    /** 
     * Given a collection of string representation of hosts, return a list of
     * corresponding IP addresses in the textual representation.
     * 
     * @param names a collection of string representations of hosts
     * @return a list of corresponding IP addresses in the string format
     * @see #normalizeHostName(String)
     */
    public static List<String> normalizeHostNames(Collection<String> names) {
        List<String> hostNames = new ArrayList<String>(names.size());
        for (String name : names) {
            hostNames.add(normalizeHostName(name));
        }
        return hostNames;
    }

    /**
     * Performs a sanity check on the list of hostnames/IPs to verify they at least
     * appear to be valid.
     * @param names - List of hostnames/IPs
     * @throws UnknownHostException
     */
    public static void verifyHostnames(String[] names) throws UnknownHostException {
        for (String name : names) {
            if (name == null) {
                throw new UnknownHostException("null hostname found");
            }
            // The first check supports URL formats (e.g. hdfs://, etc.). 
            // java.net.URI requires a schema, so we add a dummy one if it doesn't
            // have one already.
            URI uri = null;
            try {
                uri = new URI(name);
                if (uri.getHost() == null) {
                    uri = new URI("http://" + name);
                }
            } catch (URISyntaxException e) {
                uri = null;
            }
            if (uri == null || uri.getHost() == null) {
                throw new UnknownHostException(name + " is not a valid Inet address");
            }
        }
    }

    /**
     * Checks if {@code host} is a local host name and return {@link InetAddress}
     * corresponding to that address.
     * 
     * @param host the specified host
     * @return a valid local {@link InetAddress} or null
     * @throws SocketException if an I/O error occurs
     */
    public static InetAddress getLocalInetAddress(String host) throws SocketException {
        if (host == null) {
            return null;
        }
        InetAddress addr = null;
        try {
            addr = InetAddress.getByName(host);
            if (NetworkInterface.getByInetAddress(addr) == null) {
                addr = null; // Not a local address
            }
        } catch (UnknownHostException ignore) {
        }
        return addr;
    }
}