org.apache.hadoop.net.NetUtils Maven / Gradle / Ivy
/**
* 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.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.reflect.Constructor;
import java.net.BindException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.NetworkInterface;
import java.net.NoRouteToHostException;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketAddress;
import java.net.SocketException;
import java.net.SocketTimeoutException;
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.regex.Pattern;
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.commons.net.util.SubnetUtils;
import org.apache.commons.net.util.SubnetUtils.SubnetInfo;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.CommonConfigurationKeysPublic;
import org.apache.hadoop.ipc.Server;
import org.apache.hadoop.ipc.VersionedProtocol;
import org.apache.hadoop.security.SecurityUtil;
import org.apache.hadoop.util.ReflectionUtils;
import com.google.common.base.Preconditions;
@InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"})
@InterfaceStability.Unstable
public class NetUtils {
private static final Log LOG = LogFactory.getLog(NetUtils.class);
private static Map hostToResolved =
new HashMap();
/** text to point users elsewhere: {@value} */
private static final String FOR_MORE_DETAILS_SEE
= " For more details see: ";
/** text included in wrapped exceptions if the host is null: {@value} */
public static final String UNKNOWN_HOST = "(unknown)";
/** Base URL of the Hadoop Wiki: {@value} */
public static final String HADOOP_WIKI = "http://wiki.apache.org/hadoop/";
/**
* Get the socket factory for the given class according to its
* configuration parameter
* hadoop.rpc.socket.factory.class.<ClassName>. When no
* such parameter exists then fall back on the default socket factory as
* configured by hadoop.rpc.socket.factory.class.default. 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 hadoop.rpc.socket.factory.default
*
* @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(
CommonConfigurationKeysPublic.HADOOP_RPC_SOCKET_FACTORY_CLASS_DEFAULT_KEY,
CommonConfigurationKeysPublic.HADOOP_RPC_SOCKET_FACTORY_CLASS_DEFAULT_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:
* :
* ://:/
*/
public static InetSocketAddress createSocketAddr(String target) {
return createSocketAddr(target, -1);
}
/**
* Util method to build socket addr from either:
*
* :
* ://:/
*/
public static InetSocketAddress createSocketAddr(String target,
int defaultPort) {
return createSocketAddr(target, defaultPort, null);
}
/**
* Create an InetSocketAddress from the given target string and
* default port. If the string cannot be parsed correctly, the
* configName parameter is used as part of the
* exception message, allowing the user to better diagnose
* the misconfiguration.
*
* @param target a string of either "host" or "host:port"
* @param defaultPort the default port if target does not
* include a port number
* @param configName the name of the configuration from which
* target was loaded. This is used in the
* exception message in the case that parsing fails.
*/
public static InetSocketAddress createSocketAddr(String target,
int defaultPort,
String configName) {
String helpText = "";
if (configName != null) {
helpText = " (configuration property '" + configName + "')";
}
if (target == null) {
throw new IllegalArgumentException("Target address cannot be null." +
helpText);
}
target = target.trim();
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 + helpText
);
}
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 + helpText
);
}
return createSocketAddrForHost(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 createSocketAddrForHost(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
*/
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 final ConcurrentHashMap canonicalizedHostCache =
new ConcurrentHashMap();
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.putIfAbsent(host, fqHost);
} catch (UnknownHostException e) {
fqHost = host;
}
}
return fqHost;
}
/**
* 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 getAllStaticResolutions() {
synchronized (hostToResolved) {
Set >entries = hostToResolved.entrySet();
if (entries.size() == 0) {
return null;
}
List l = new ArrayList(entries.size());
for (Entry 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 "hostname:port" of the server,
* or "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) {
return getConnectAddress(server.getListenerAddress());
}
/**
* Returns an InetSocketAddress that a client can use to connect to the
* given listening address.
*
* @param addr of a listener
* @return socket address that a client can use to connect to the server.
*/
public static InetSocketAddress getConnectAddress(InetSocketAddress addr) {
if (!addr.isUnresolved() && addr.getAddress().isAnyLocalAddress()) {
try {
addr = new InetSocketAddress(InetAddress.getLocalHost(), addr.getPort());
} catch (UnknownHostException uhe) {
// shouldn't get here unless the host doesn't have a loopback iface
addr = createSocketAddrForHost("127.0.0.1", addr.getPort());
}
}
return addr;
}
/**
* Same as getInputStream(socket, socket.getSoTimeout()).
*
*
* @see #getInputStream(Socket, long)
*/
public static SocketInputWrapper getInputStream(Socket socket)
throws IOException {
return getInputStream(socket, socket.getSoTimeout());
}
/**
* Return a {@link SocketInputWrapper} for the socket and set the given
* timeout. If the socket does not have an associated channel, then its socket
* timeout will be set to the specified value. Otherwise, a
* {@link SocketInputStream} will be created which reads with the configured
* timeout.
*
* Any socket created using socket factories returned by {@link #NetUtils},
* must use this interface instead of {@link Socket#getInputStream()}.
*
* In general, this should be called only once on each socket: see the note
* in {@link SocketInputWrapper#setTimeout(long)} for more information.
*
* @see Socket#getChannel()
*
* @param socket
* @param timeout timeout in milliseconds. zero for waiting as
* long as necessary.
* @return SocketInputWrapper for reading from the socket.
* @throws IOException
*/
public static SocketInputWrapper getInputStream(Socket socket, long timeout)
throws IOException {
InputStream stm = (socket.getChannel() == null) ?
socket.getInputStream() : new SocketInputStream(socket);
SocketInputWrapper w = new SocketInputWrapper(socket, stm);
w.setTimeout(timeout);
return w;
}
/**
* Same as getOutputStream(socket, 0). Timeout of zero implies write will
* wait until data is available.
*
* From documentation for {@link #getOutputStream(Socket, long)} :
* 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.
*
* 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.
*
* 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 socket.connect(endpoint, timeout). If
* socket.getChannel() 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 address the remote address
* @param timeout timeout in milliseconds
*/
public static void connect(Socket socket,
SocketAddress address,
int timeout) throws IOException {
connect(socket, address, null, timeout);
}
/**
* Like {@link NetUtils#connect(Socket, SocketAddress, int)} but
* also takes a local address and port to bind the socket to.
*
* @param socket
* @param endpoint the remote address
* @param localAddr the local address to bind the socket to
* @param timeout timeout in milliseconds
*/
public static void connect(Socket socket,
SocketAddress endpoint,
SocketAddress localAddr,
int timeout) throws IOException {
if (socket == null || endpoint == null || timeout < 0) {
throw new IllegalArgumentException("Illegal argument for connect()");
}
SocketChannel ch = socket.getChannel();
if (localAddr != null) {
Class localClass = localAddr.getClass();
Class remoteClass = endpoint.getClass();
Preconditions.checkArgument(localClass.equals(remoteClass),
"Local address %s must be of same family as remote address %s.",
localAddr, endpoint);
socket.bind(localAddr);
}
try {
if (ch == null) {
// let the default implementation handle it.
socket.connect(endpoint, timeout);
} else {
SocketIOWithTimeout.connect(ch, endpoint, timeout);
}
} catch (SocketTimeoutException ste) {
throw new ConnectTimeoutException(ste.getMessage());
}
// 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) {
try {
return InetAddress.getByName(name).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 normalizeHostNames(Collection names) {
List hostNames = new ArrayList(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");
}
}
}
private static final Pattern ipPortPattern = // Pattern for matching ip[:port]
Pattern.compile("\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}(:\\d+)?");
/**
* Attempt to obtain the host name of the given string which contains
* an IP address and an optional port.
*
* @param ipPort string of form ip[:port]
* @return Host name or null if the name can not be determined
*/
public static String getHostNameOfIP(String ipPort) {
if (null == ipPort || !ipPortPattern.matcher(ipPort).matches()) {
return null;
}
try {
int colonIdx = ipPort.indexOf(':');
String ip = (-1 == colonIdx) ? ipPort
: ipPort.substring(0, ipPort.indexOf(':'));
return InetAddress.getByName(ip).getHostName();
} catch (UnknownHostException e) {
return null;
}
}
/**
* Return hostname without throwing exception.
* @return hostname
*/
public static String getHostname() {
try {return "" + InetAddress.getLocalHost();}
catch(UnknownHostException uhe) {return "" + uhe;}
}
/**
* Compose a "host:port" string from the address.
*/
public static String getHostPortString(InetSocketAddress addr) {
return addr.getHostName() + ":" + addr.getPort();
}
/**
* 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 = SecurityUtil.getByName(host);
if (NetworkInterface.getByInetAddress(addr) == null) {
addr = null; // Not a local address
}
} catch (UnknownHostException ignore) { }
return addr;
}
/**
* Given an InetAddress, checks to see if the address is a local address, by
* comparing the address with all the interfaces on the node.
* @param addr address to check if it is local node's address
* @return true if the address corresponds to the local node
*/
public static boolean isLocalAddress(InetAddress addr) {
// Check if the address is any local or loop back
boolean local = addr.isAnyLocalAddress() || addr.isLoopbackAddress();
// Check if the address is defined on any interface
if (!local) {
try {
local = NetworkInterface.getByInetAddress(addr) != null;
} catch (SocketException e) {
local = false;
}
}
return local;
}
/**
* Take an IOException , the local host port and remote host port details and
* return an IOException with the input exception as the cause and also
* include the host details. The new exception provides the stack trace of the
* place where the exception is thrown and some extra diagnostics information.
* If the exception is BindException or ConnectException or
* UnknownHostException or SocketTimeoutException, return a new one of the
* same type; Otherwise return an IOException.
*
* @param destHost target host (nullable)
* @param destPort target port
* @param localHost local host (nullable)
* @param localPort local port
* @param exception the caught exception.
* @return an exception to throw
*/
public static IOException wrapException(final String destHost,
final int destPort,
final String localHost,
final int localPort,
final IOException exception) {
if (exception instanceof BindException) {
return wrapWithMessage(exception,
"Problem binding to ["
+ localHost
+ ":"
+ localPort
+ "] "
+ exception
+ ";"
+ see("BindException"));
} else if (exception instanceof ConnectException) {
// connection refused; include the host:port in the error
return wrapWithMessage(exception,
"Call From "
+ localHost
+ " to "
+ destHost
+ ":"
+ destPort
+ " failed on connection exception: "
+ exception
+ ";"
+ see("ConnectionRefused"));
} else if (exception instanceof UnknownHostException) {
return wrapWithMessage(exception,
"Invalid host name: "
+ getHostDetailsAsString(destHost, destPort, localHost)
+ exception
+ ";"
+ see("UnknownHost"));
} else if (exception instanceof SocketTimeoutException) {
return wrapWithMessage(exception,
"Call From "
+ localHost + " to " + destHost + ":" + destPort
+ " failed on socket timeout exception: " + exception
+ ";"
+ see("SocketTimeout"));
} else if (exception instanceof NoRouteToHostException) {
return wrapWithMessage(exception,
"No Route to Host from "
+ localHost + " to " + destHost + ":" + destPort
+ " failed on socket timeout exception: " + exception
+ ";"
+ see("NoRouteToHost"));
} else if (exception instanceof EOFException) {
return wrapWithMessage(exception,
"End of File Exception between "
+ getHostDetailsAsString(destHost, destPort, localHost)
+ ": " + exception
+ ";"
+ see("EOFException"));
}
else {
return (IOException) new IOException("Failed on local exception: "
+ exception
+ "; Host Details : "
+ getHostDetailsAsString(destHost, destPort, localHost))
.initCause(exception);
}
}
private static String see(final String entry) {
return FOR_MORE_DETAILS_SEE + HADOOP_WIKI + entry;
}
@SuppressWarnings("unchecked")
private static T wrapWithMessage(
T exception, String msg) {
Class clazz = exception.getClass();
try {
Constructor ctor = clazz.getConstructor(String.class);
Throwable t = ctor.newInstance(msg);
return (T)(t.initCause(exception));
} catch (Throwable e) {
LOG.warn("Unable to wrap exception of type " +
clazz + ": it has no (String) constructor", e);
return exception;
}
}
/**
* Get the host details as a string
* @param destHost destinatioon host (nullable)
* @param destPort destination port
* @param localHost local host (nullable)
* @return a string describing the destination host:port and the local host
*/
private static String getHostDetailsAsString(final String destHost,
final int destPort,
final String localHost) {
StringBuilder hostDetails = new StringBuilder(27);
hostDetails.append("local host is: ")
.append(quoteHost(localHost))
.append("; ");
hostDetails.append("destination host is: ").append(quoteHost(destHost))
.append(":")
.append(destPort).append("; ");
return hostDetails.toString();
}
/**
* Quote a hostname if it is not null
* @param hostname the hostname; nullable
* @return a quoted hostname or {@link #UNKNOWN_HOST} if the hostname is null
*/
private static String quoteHost(final String hostname) {
return (hostname != null) ?
("\"" + hostname + "\"")
: UNKNOWN_HOST;
}
/**
* @return true if the given string is a subnet specified
* using CIDR notation, false otherwise
*/
public static boolean isValidSubnet(String subnet) {
try {
new SubnetUtils(subnet);
return true;
} catch (IllegalArgumentException iae) {
return false;
}
}
/**
* Add all addresses associated with the given nif in the
* given subnet to the given list.
*/
private static void addMatchingAddrs(NetworkInterface nif,
SubnetInfo subnetInfo, List addrs) {
Enumeration ifAddrs = nif.getInetAddresses();
while (ifAddrs.hasMoreElements()) {
InetAddress ifAddr = ifAddrs.nextElement();
if (subnetInfo.isInRange(ifAddr.getHostAddress())) {
addrs.add(ifAddr);
}
}
}
/**
* Return an InetAddress for each interface that matches the
* given subnet specified using CIDR notation.
*
* @param subnet subnet specified using CIDR notation
* @param returnSubinterfaces
* whether to return IPs associated with subinterfaces
* @throws IllegalArgumentException if subnet is invalid
*/
public static List getIPs(String subnet,
boolean returnSubinterfaces) {
List addrs = new ArrayList();
SubnetInfo subnetInfo = new SubnetUtils(subnet).getInfo();
Enumeration nifs;
try {
nifs = NetworkInterface.getNetworkInterfaces();
} catch (SocketException e) {
LOG.error("Unable to get host interfaces", e);
return addrs;
}
while (nifs.hasMoreElements()) {
NetworkInterface nif = nifs.nextElement();
// NB: adding addresses even if the nif is not up
addMatchingAddrs(nif, subnetInfo, addrs);
if (!returnSubinterfaces) {
continue;
}
Enumeration subNifs = nif.getSubInterfaces();
while (subNifs.hasMoreElements()) {
addMatchingAddrs(subNifs.nextElement(), subnetInfo, addrs);
}
}
return addrs;
}
/**
* Return a free port number. There is no guarantee it will remain free, so
* it should be used immediately.
*
* @returns A free port for binding a local socket
*/
public static int getFreeSocketPort() {
int port = 0;
try {
ServerSocket s = new ServerSocket(0);
port = s.getLocalPort();
s.close();
return port;
} catch (IOException e) {
// Could not get a free port. Return default port 0.
}
return port;
}
}
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