/*
* Copyright (c) 1995, 2025, 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
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*/
package java.net;
import java.net.spi.InetAddressResolver;
import java.net.spi.InetAddressResolverProvider;
import java.net.spi.InetAddressResolver.LookupPolicy;
import java.util.List;
import java.util.NavigableSet;
import java.util.ArrayList;
import java.util.Objects;
import java.util.Scanner;
import java.io.File;
import java.io.ObjectStreamException;
import java.io.ObjectStreamField;
import java.io.IOException;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.ObjectInputStream.GetField;
import java.io.ObjectOutputStream;
import java.io.ObjectOutputStream.PutField;
import java.io.Serializable;
import java.lang.annotation.Native;
import java.util.ServiceLoader;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ConcurrentSkipListSet;
import java.util.concurrent.atomic.AtomicLong;
import java.util.Arrays;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.stream.Stream;
import jdk.internal.util.Exceptions;
import jdk.internal.access.JavaNetInetAddressAccess;
import jdk.internal.access.SharedSecrets;
import jdk.internal.misc.Blocker;
import jdk.internal.misc.VM;
import jdk.internal.vm.annotation.Stable;
import sun.net.ResolverProviderConfiguration;
import sun.net.InetAddressCachePolicy;
import sun.net.util.IPAddressUtil;
import sun.nio.cs.UTF_8;
import static java.net.spi.InetAddressResolver.LookupPolicy.IPV4;
import static java.net.spi.InetAddressResolver.LookupPolicy.IPV4_FIRST;
import static java.net.spi.InetAddressResolver.LookupPolicy.IPV6;
import static java.net.spi.InetAddressResolver.LookupPolicy.IPV6_FIRST;
import static jdk.internal.util.Exceptions.filterNonSocketInfo;
import static jdk.internal.util.Exceptions.formatMsg;
/**
* This class represents an Internet Protocol (IP) address.
*
* An IP address is either a 32-bit or 128-bit unsigned number
* used by IP, a lower-level protocol on which protocols like UDP and
* TCP are built. The IP address architecture is defined by RFC 790:
* Assigned Numbers, RFC 1918:
* Address Allocation for Private Internets, RFC 2365:
* Administratively Scoped IP Multicast, and RFC 2373: IP
* Version 6 Addressing Architecture. An instance of an
* InetAddress consists of an IP address and possibly its
* corresponding host name (depending on whether it is constructed
* with a host name or whether it has already done reverse host name
* resolution).
*
*
Address types
*
*
* Description of unicast and multicast address types
*
* | Address Type | Description |
|---|
*
*
* | unicast |
* An identifier for a single interface. A packet sent to
* a unicast address is delivered to the interface identified by
* that address.
*
* The Unspecified Address -- Also called anylocal or wildcard
* address. It must never be assigned to any node. It indicates the
* absence of an address. One example of its use is as the target of
* bind, which allows a server to accept a client connection on any
* interface, in case the server host has multiple interfaces.
*
* The unspecified address must not be used as
* the destination address of an IP packet.
*
* The Loopback Addresses -- This is the address
* assigned to the loopback interface. Anything sent to this
* IP address loops around and becomes IP input on the local
* host. This address is often used when testing a
* client. |
|---|
* | multicast |
* An identifier for a set of interfaces (typically belonging
* to different nodes). A packet sent to a multicast address is
* delivered to all interfaces identified by that address. |
|---|
*
*
*
* IP address scope
*
* Link-local addresses are designed to be used for addressing
* on a single link for purposes such as auto-address configuration,
* neighbor discovery, or when no routers are present.
*
*
Site-local addresses are designed to be used for addressing
* inside of a site without the need for a global prefix.
*
*
Global addresses are unique across the internet.
*
*
*
* The textual representation of an IP address is address family specific.
*
*
*
* For IPv4 address format, please refer to the supported
* {@linkplain Inet4Address##format IPv4 address textual representations};
* For IPv6 address format, please refer to the supported
* {@linkplain Inet6Address##format IPv6 address textual representations}.
*
*
There are a couple of
* System Properties affecting how IPv4 and IPv6 addresses are used.
*
*
Host Name Resolution
*
* The InetAddress class provides methods to resolve host names to
* their IP addresses and vice versa. The actual resolution is delegated to an
* {@linkplain InetAddressResolver InetAddress resolver}.
*
*
Host name-to-IP address resolution maps a host name to an IP address.
* For any host name, its corresponding IP address is returned.
*
*
Reverse name resolution means that for any IP address,
* the host associated with the IP address is returned.
*
*
The built-in InetAddress resolver implementation does
* host name-to-IP address resolution and vice versa through the use of
* a combination of local machine configuration information and network
* naming services such as the Domain Name System (DNS) and the Lightweight Directory
* Access Protocol (LDAP).
* The particular naming services that the built-in resolver uses by default
* depends on the configuration of the local machine.
*
*
{@code InetAddress} has a service provider mechanism for InetAddress resolvers
* that allows a custom InetAddress resolver to be used instead of the built-in implementation.
* {@link InetAddressResolverProvider} is the service provider class. Its API docs provide all the
* details on this mechanism.
*
*
InetAddress Caching
*
* The InetAddress class has a cache to store successful as well as
* unsuccessful host name resolutions.
*
* The default behavior is to cache entries for a finite (implementation
* dependent) period of time. The result of unsuccessful host
* name resolution is cached for a very short period of time (10
* seconds) to improve performance.
*
*
If the default behavior is not desired, then a Java security property
* can be set to a different Time-to-live (TTL) value for positive
* caching. Likewise, a system admin can configure a different
* negative caching TTL value when needed or extend the usage of the stale data.
*
*
Three Java {@linkplain java.security.Security security} properties control
* the TTL values used for positive and negative host name resolution caching:
*
*
* - networkaddress.cache.ttl
* - Indicates the caching policy for successful name lookups from
* the name service. The value is specified as an integer to indicate
* the number of seconds to cache the successful lookup. The default
* setting is to cache for an implementation specific period of time.
*
* A value of -1 indicates "cache forever".
*
* - networkaddress.cache.stale.ttl
* - Indicates the caching policy for stale names. The value is specified as
* an integer to indicate the number of seconds that stale names will be kept in
* the cache. A name is considered stale if the TTL has expired and an attempt
* to lookup the host name again was not successful. This property is useful if
* it is preferable to use a stale name rather than fail due to an unsuccessful
* lookup. The default setting is to cache for an implementation specific period
* of time.
*
* If the value of this property is larger than "networkaddress.cache.ttl" then
* "networkaddress.cache.ttl" will be used as a refresh interval of the name in
* the cache. For example, if this property is set to 1 day and
* "networkaddress.cache.ttl" is set to 30 seconds, then the positive response
* will be cached for 1 day but an attempt to refresh it will be done every
* 30 seconds.
*
* A value of 0 (zero) or if the property is not set means do not use stale
* names. Negative values are ignored.
*
* - networkaddress.cache.negative.ttl (default: 10)
* - Indicates the caching policy for un-successful name lookups
* from the name service. The value is specified as an integer to
* indicate the number of seconds to cache the failure for
* un-successful lookups.
*
* A value of 0 indicates "never cache".
* A value of -1 indicates "cache forever".
*
*
*
* @spec https://www.rfc-editor.org/info/rfc1918
* RFC 1918: Address Allocation for Private Internets
* @spec https://www.rfc-editor.org/info/rfc2365
* RFC 2365: Administratively Scoped IP Multicast
* @spec https://www.rfc-editor.org/info/rfc2373
* RFC 2373: IP Version 6 Addressing Architecture
* @spec https://www.rfc-editor.org/info/rfc790
* RFC 790: Assigned numbers
* @author Chris Warth
* @see java.net.InetAddress#getByAddress(byte[])
* @see java.net.InetAddress#getByAddress(java.lang.String, byte[])
* @see java.net.InetAddress#getAllByName(java.lang.String)
* @see java.net.InetAddress#getByName(java.lang.String)
* @see java.net.InetAddress#getLocalHost()
* @since 1.0
* @sealedGraph
*/
public sealed class InetAddress implements Serializable permits Inet4Address, Inet6Address {
/**
* Specify the address family: Internet Protocol, Version 4
* @since 1.4
*/
@Native static final int IPv4 = 1;
/**
* Specify the address family: Internet Protocol, Version 6
* @since 1.4
*/
@Native static final int IPv6 = 2;
static class InetAddressHolder {
/**
* Reserve the original application specified hostname.
*
* The original hostname is useful for domain-based endpoint
* identification (see RFC 2818 and RFC 6125). If an address
* was created with a raw IP address, a reverse name lookup
* may introduce endpoint identification security issue via
* DNS forging.
*
* Oracle JSSE provider is using this original hostname, via
* jdk.internal.misc.JavaNetAccess, for SSL/TLS endpoint identification.
*
* Note: May define a new public method in the future if necessary.
*/
String originalHostName;
InetAddressHolder() {}
InetAddressHolder(String hostName, int address, int family) {
this.originalHostName = hostName;
this.hostName = hostName;
this.address = address;
this.family = family;
}
void init(String hostName, int family) {
this.originalHostName = hostName;
this.hostName = hostName;
if (family != -1) {
this.family = family;
}
}
String hostName;
String getHostName() {
return hostName;
}
String getOriginalHostName() {
return originalHostName;
}
/**
* Holds a 32-bit IPv4 address.
*/
int address;
int getAddress() {
return address;
}
/**
* Specifies the address family type, for instance, '1' for IPv4
* addresses, and '2' for IPv6 addresses.
*/
int family;
int getFamily() {
return family;
}
}
/* Used to store the serializable fields of InetAddress */
final transient InetAddressHolder holder;
InetAddressHolder holder() {
return holder;
}
/* Used to store the system-wide resolver */
@Stable
private static volatile InetAddressResolver resolver;
private static final InetAddressResolver BUILTIN_RESOLVER;
/**
* Used to store the best available hostname.
* Lazily initialized via a data race; safe because Strings are immutable.
*/
private transient String canonicalHostName = null;
/** use serialVersionUID from JDK 1.0.2 for interoperability */
@java.io.Serial
private static final long serialVersionUID = 3286316764910316507L;
// "java.net.preferIPv4Stack" system property value
private static final String PREFER_IPV4_STACK_VALUE;
// "java.net.preferIPv6Addresses" system property value
private static final String PREFER_IPV6_ADDRESSES_VALUE;
// "jdk.net.hosts.file" system property value
private static final String HOSTS_FILE_NAME;
/*
* Load net library into runtime, and perform initializations.
*/
static {
PREFER_IPV4_STACK_VALUE =
System.getProperty("java.net.preferIPv4Stack");
PREFER_IPV6_ADDRESSES_VALUE =
System.getProperty("java.net.preferIPv6Addresses");
HOSTS_FILE_NAME =
System.getProperty("jdk.net.hosts.file");
jdk.internal.loader.BootLoader.loadLibrary("net");
SharedSecrets.setJavaNetInetAddressAccess(
new JavaNetInetAddressAccess() {
public String getOriginalHostName(InetAddress ia) {
return ia.holder.getOriginalHostName();
}
public int addressValue(Inet4Address inet4Address) {
return inet4Address.addressValue();
}
public byte[] addressBytes(Inet6Address inet6Address) {
return inet6Address.addressBytes();
}
}
);
Exceptions.setup(); // needed for native exceptions
init();
}
/**
* Creates an address lookup policy from {@code "java.net.preferIPv4Stack"},
* {@code "java.net.preferIPv6Addresses"} system property values, and O/S configuration.
*/
private static final LookupPolicy initializePlatformLookupPolicy() {
// Calculate AddressFamily value first
boolean ipv4Available = isIPv4Available();
if ("true".equals(PREFER_IPV4_STACK_VALUE) && ipv4Available) {
return LookupPolicy.of(IPV4);
}
// Check if IPv6 is not supported
if (InetAddress.impl instanceof Inet4AddressImpl) {
return LookupPolicy.of(IPV4);
}
// Check if system supports IPv4, if not use IPv6
if (!ipv4Available) {
return LookupPolicy.of(IPV6);
}
// If both address families are needed - check preferIPv6Addresses value
if (PREFER_IPV6_ADDRESSES_VALUE != null) {
if (PREFER_IPV6_ADDRESSES_VALUE.equalsIgnoreCase("true")) {
return LookupPolicy.of(IPV4 | IPV6 | IPV6_FIRST);
}
if (PREFER_IPV6_ADDRESSES_VALUE.equalsIgnoreCase("false")) {
return LookupPolicy.of(IPV4 | IPV6 | IPV4_FIRST);
}
if (PREFER_IPV6_ADDRESSES_VALUE.equalsIgnoreCase("system")) {
return LookupPolicy.of(IPV4 | IPV6);
}
}
// Default value with both address families needed - IPv4 addresses come first
return LookupPolicy.of(IPV4 | IPV6 | IPV4_FIRST);
}
static boolean systemAddressesOrder(int lookupCharacteristics) {
return (lookupCharacteristics & (IPV4_FIRST | IPV6_FIRST)) == 0;
}
static boolean ipv4AddressesFirst(int lookupCharacteristics) {
return (lookupCharacteristics & IPV4_FIRST) != 0;
}
static boolean ipv6AddressesFirst(int lookupCharacteristics) {
return (lookupCharacteristics & IPV6_FIRST) != 0;
}
// Native method to check if IPv4 is available
private static native boolean isIPv4Available();
// Native method to check if IPv6 is available
private static native boolean isIPv6Supported();
private static final ReentrantLock RESOLVER_LOCK = new ReentrantLock();
private static volatile InetAddressResolver bootstrapResolver;
private static InetAddressResolver resolver() {
InetAddressResolver cns = resolver;
if (cns != null) {
return cns;
}
if (VM.isBooted()) {
RESOLVER_LOCK.lock();
boolean bootstrapSet = false;
try {
cns = resolver;
if (cns != null) {
return cns;
}
// Protection against provider calling InetAddress APIs during initialization
if (bootstrapResolver != null) {
return bootstrapResolver;
}
bootstrapResolver = BUILTIN_RESOLVER;
bootstrapSet = true;
if (HOSTS_FILE_NAME != null) {
// The default resolver service is already host file resolver
cns = BUILTIN_RESOLVER;
} else {
cns = loadResolver();
}
InetAddress.resolver = cns;
return cns;
} finally {
// We want to clear bootstrap resolver reference only after an attempt to
// instantiate a resolver has been completed.
if (bootstrapSet) {
bootstrapResolver = null;
}
RESOLVER_LOCK.unlock();
}
} else {
return BUILTIN_RESOLVER;
}
}
private static InetAddressResolver loadResolver() {
return ServiceLoader.load(InetAddressResolverProvider.class)
.findFirst()
.map(nsp -> nsp.get(builtinConfiguration()))
.orElse(BUILTIN_RESOLVER);
}
private static InetAddressResolverProvider.Configuration builtinConfiguration() {
return new ResolverProviderConfiguration(BUILTIN_RESOLVER, () -> {
try {
return impl.getLocalHostName();
} catch (UnknownHostException unknownHostException) {
return "localhost";
}
});
}
/**
* Constructor for the Socket.accept() method.
* This creates an empty InetAddress, which is filled in by
* the accept() method. This InetAddress, however, is not
* put in the address cache, since it is not created by name.
*/
InetAddress() {
holder = new InetAddressHolder();
}
/**
* Replaces the de-serialized object with an Inet4Address object.
*
* @return the alternate object to the de-serialized object.
*
* @throws ObjectStreamException if a new object replacing this
* object could not be created
*/
@java.io.Serial
private Object readResolve() throws ObjectStreamException {
// will replace the deserialized 'this' object
return new Inet4Address(holder().getHostName(), holder().getAddress());
}
/**
* Utility routine to check if the InetAddress is an
* IP multicast address.
* @return a {@code boolean} indicating if the InetAddress is
* an IP multicast address
* @since 1.1
*/
public boolean isMulticastAddress() {
return false;
}
/**
* Utility routine to check if the InetAddress is a wildcard address.
* @return a {@code boolean} indicating if the InetAddress is
* a wildcard address.
* @since 1.4
*/
public boolean isAnyLocalAddress() {
return false;
}
/**
* Utility routine to check if the InetAddress is a loopback address.
*
* @return a {@code boolean} indicating if the InetAddress is
* a loopback address; or false otherwise.
* @since 1.4
*/
public boolean isLoopbackAddress() {
return false;
}
/**
* Utility routine to check if the InetAddress is a link local address.
*
* @return a {@code boolean} indicating if the InetAddress is
* a link local address; or false if address is not a link local unicast address.
* @since 1.4
*/
public boolean isLinkLocalAddress() {
return false;
}
/**
* Utility routine to check if the InetAddress is a site local address.
*
* @return a {@code boolean} indicating if the InetAddress is
* a site local address; or false if address is not a site local unicast address.
* @since 1.4
*/
public boolean isSiteLocalAddress() {
return false;
}
/**
* Utility routine to check if the multicast address has global scope.
*
* @return a {@code boolean} indicating if the address has
* is a multicast address of global scope, false if it is not
* of global scope or it is not a multicast address
* @since 1.4
*/
public boolean isMCGlobal() {
return false;
}
/**
* Utility routine to check if the multicast address has node scope.
*
* @return a {@code boolean} indicating if the address has
* is a multicast address of node-local scope, false if it is not
* of node-local scope or it is not a multicast address
* @since 1.4
*/
public boolean isMCNodeLocal() {
return false;
}
/**
* Utility routine to check if the multicast address has link scope.
*
* @return a {@code boolean} indicating if the address has
* is a multicast address of link-local scope, false if it is not
* of link-local scope or it is not a multicast address
* @since 1.4
*/
public boolean isMCLinkLocal() {
return false;
}
/**
* Utility routine to check if the multicast address has site scope.
*
* @return a {@code boolean} indicating if the address has
* is a multicast address of site-local scope, false if it is not
* of site-local scope or it is not a multicast address
* @since 1.4
*/
public boolean isMCSiteLocal() {
return false;
}
/**
* Utility routine to check if the multicast address has organization scope.
*
* @return a {@code boolean} indicating if the address has
* is a multicast address of organization-local scope,
* false if it is not of organization-local scope
* or it is not a multicast address
* @since 1.4
*/
public boolean isMCOrgLocal() {
return false;
}
/**
* Test whether that address is reachable. Best effort is made by the
* implementation to try to reach the host, but firewalls and server
* configuration may block requests resulting in an unreachable status
* while some specific ports may be accessible.
* A typical implementation will use ICMP ECHO REQUESTs if the
* privilege can be obtained, otherwise it will try to establish
* a TCP connection on port 7 (Echo) of the destination host.
*
* The timeout value, in milliseconds, indicates the maximum amount of time
* the try should take. If the operation times out before getting an
* answer, the host is deemed unreachable. A negative value will result
* in an IllegalArgumentException being thrown.
*
* @param timeout the time, in milliseconds, before the call aborts
* @return a {@code boolean} indicating if the address is reachable.
* @throws IOException if a network error occurs
* @throws IllegalArgumentException if {@code timeout} is negative.
* @since 1.5
*/
public boolean isReachable(int timeout) throws IOException {
return isReachable(null, 0 , timeout);
}
/**
* Test whether that address is reachable. Best effort is made by the
* implementation to try to reach the host, but firewalls and server
* configuration may block requests resulting in a unreachable status
* while some specific ports may be accessible.
* A typical implementation will use ICMP ECHO REQUESTs if the
* privilege can be obtained, otherwise it will try to establish
* a TCP connection on port 7 (Echo) of the destination host.
*
* The {@code network interface} and {@code ttl} parameters
* let the caller specify which network interface the test will go through
* and the maximum number of hops the packets should go through.
* A negative value for the {@code ttl} will result in an
* IllegalArgumentException being thrown.
*
* The timeout value, in milliseconds, indicates the maximum amount of time
* the try should take. If the operation times out before getting an
* answer, the host is deemed unreachable. A negative value will result
* in an IllegalArgumentException being thrown.
*
* @param netif the NetworkInterface through which the
* test will be done, or null for any interface
* @param ttl the maximum numbers of hops to try or 0 for the
* default
* @param timeout the time, in milliseconds, before the call aborts
* @throws IllegalArgumentException if either {@code timeout}
* or {@code ttl} are negative.
* @return a {@code boolean} indicating if the address is reachable.
* @throws IOException if a network error occurs
* @since 1.5
*/
public boolean isReachable(NetworkInterface netif, int ttl,
int timeout) throws IOException {
if (ttl < 0)
throw new IllegalArgumentException("ttl can't be negative");
if (timeout < 0)
throw new IllegalArgumentException("timeout can't be negative");
return impl.isReachable(this, timeout, netif, ttl);
}
/**
* Gets the host name for this IP address.
*
*
If this InetAddress was created with a host name,
* this host name will be remembered and returned;
* otherwise, a reverse name lookup will be performed
* and the result will be returned based on the system-wide
* resolver. If a lookup of the name service
* is required, call
* {@link #getCanonicalHostName() getCanonicalHostName}.
*
* @return the host name for this IP address
*
* @see InetAddress#getCanonicalHostName
*/
public String getHostName() {
if (holder().getHostName() == null) {
holder().hostName = InetAddress.getHostFromNameService(this);
}
return holder().getHostName();
}
/**
* Gets the fully qualified domain name for this
* {@linkplain InetAddress#getAddress() IP address} using the system-wide
* {@linkplain InetAddressResolver resolver}.
*
*
The system-wide resolver will be used to do a reverse name lookup of the IP address.
* The lookup can fail for many reasons that include the host not being registered with the name
* service. If the resolver is unable to determine the fully qualified
* domain name, this method returns the {@linkplain #getHostAddress() textual representation}
* of the IP address.
*
* @return the fully qualified domain name for this IP address.
* If the system-wide resolver wasn't able to determine the
* fully qualified domain name for the IP address, the textual
* representation of the IP address is returned instead.
*
* @since 1.4
*/
public String getCanonicalHostName() {
String value = canonicalHostName;
if (value == null)
canonicalHostName = value =
InetAddress.getHostFromNameService(this);
return value;
}
/**
* Returns the fully qualified domain name for the given address.
*
* @return the fully qualified domain name for the given IP address.
* If the system-wide resolver wasn't able to determine the
* fully qualified domain name for the IP address, the textual
* representation of the IP address is returned instead.
*/
private static String getHostFromNameService(InetAddress addr) {
String host;
var resolver = resolver();
try {
// first lookup the hostname
host = resolver.lookupByAddress(addr.getAddress());
/* now get all the IP addresses for this hostname,
* and make sure one of them matches the original IP
* address. We do this to try and prevent spoofing.
*/
InetAddress[] arr = InetAddress.getAllByName0(host);
boolean ok = false;
if (arr != null) {
for (int i = 0; !ok && i < arr.length; i++) {
ok = addr.equals(arr[i]);
}
}
//XXX: if it looks like a spoof just return the address?
if (!ok) {
host = addr.getHostAddress();
return host;
}
} catch (RuntimeException | UnknownHostException e) {
// 'resolver.lookupByAddress' and 'InetAddress.getAllByName0' delegate to
// the system-wide resolver, which could be a custom one. At that point we
// treat any unexpected RuntimeException thrown by the resolver as we would
// treat an UnknownHostException or an unmatched host name.
host = addr.getHostAddress();
}
return host;
}
/**
* Returns the raw IP address of this {@code InetAddress}
* object. The result is in network byte order: the highest order
* byte of the address is in {@code getAddress()[0]}.
*
* @return the raw IP address of this object.
*/
public byte[] getAddress() {
return null;
}
/**
* Returns the IP address string in textual presentation.
*
* @return the raw IP address in a string format.
* @since 1.0.2
*/
public String getHostAddress() {
return null;
}
/**
* Returns a hashcode for this IP address.
*
* @return a hash code value for this IP address.
*/
public int hashCode() {
return -1;
}
/**
* Compares this object against the specified object.
* The result is {@code true} if and only if the argument is
* not {@code null} and it represents the same IP address as
* this object.
*
* Two instances of {@code InetAddress} represent the same IP
* address if the length of the byte arrays returned by
* {@code getAddress} is the same for both, and each of the
* array components is the same for the byte arrays.
*
* @param obj the object to compare against.
* @return {@code true} if the objects are the same;
* {@code false} otherwise.
* @see java.net.InetAddress#getAddress()
*/
public boolean equals(Object obj) {
return false;
}
/**
* Converts this IP address to a {@code String}. The
* string returned is of the form: hostname / literal IP
* address.
*
* If the host name is unresolved, no reverse lookup
* is performed. The hostname part will be represented
* by an empty string.
*
* @return a string representation of this IP address.
*/
public String toString() {
String hostName = holder().getHostName();
return Objects.toString(hostName, "")
+ "/" + getHostAddress();
}
// mapping from host name to Addresses - either NameServiceAddresses (while
// still being looked-up by NameService(s)) or CachedAddresses when cached
private static final ConcurrentMap cache =
new ConcurrentHashMap<>();
// CachedAddresses that have to expire are kept ordered in this NavigableSet
// which is scanned on each access
private static final NavigableSet expirySet =
new ConcurrentSkipListSet<>();
// common interface
private interface Addresses {
InetAddress[] get() throws UnknownHostException;
}
/**
* A cached result of a name service lookup. The result can be either valid
* addresses or invalid (ie a failed lookup) containing no addresses.
*/
private static class CachedLookup implements Addresses, Comparable {
private static final AtomicLong seq = new AtomicLong();
final String host;
volatile InetAddress[] inetAddresses;
/**
* Time of expiry (in terms of System.nanoTime()). Can be modified only
* when the record is not added to the "expirySet".
*/
volatile long expiryTime;
final long id = seq.incrementAndGet(); // each instance is unique
CachedLookup(String host, InetAddress[] inetAddresses, long expiryTime) {
this.host = host;
this.inetAddresses = inetAddresses;
this.expiryTime = expiryTime;
}
@Override
public InetAddress[] get() throws UnknownHostException {
if (inetAddresses == null) {
throw new UnknownHostException(formatMsg("%s", filterNonSocketInfo(host)));
}
return inetAddresses;
}
@Override
public int compareTo(CachedLookup other) {
// natural order is expiry time -
// compare difference of expiry times rather than
// expiry times directly, to avoid possible overflow.
// (see System.nanoTime() recommendations...)
long diff = this.expiryTime - other.expiryTime;
if (diff < 0L) return -1;
if (diff > 0L) return 1;
// ties are broken using unique id
return Long.compare(this.id, other.id);
}
/**
* Checks if the current cache record is expired or not. Expired records
* are removed from the expirySet and cache.
*
* @return {@code true} if the record was removed
*/
public boolean tryRemoveExpiredAddress(long now) {
// compare difference of time instants rather than
// time instants directly, to avoid possible overflow.
// (see System.nanoTime() recommendations...)
if ((expiryTime - now) < 0L) {
// ConcurrentSkipListSet uses weakly consistent iterator,
// so removing while iterating is OK...
if (expirySet.remove(this)) {
// ... remove from cache
cache.remove(host, this);
}
return true;
}
return false;
}
}
/**
* A cached valid lookup containing addresses whose validity may be
* temporarily extended by an additional stale period pending the mapping
* being refreshed or updated.
*/
private static final class ValidCachedLookup extends CachedLookup {
/**
* Time to refresh (in terms of System.nanoTime()).
*/
private volatile long refreshTime;
/**
* For how long the stale data should be used after TTL expiration.
* Initially equal to the expiryTime, but increased over time after each
* successful lookup.
*/
private volatile long staleTime;
/**
* only one thread is doing lookup to name service
* for particular host at any time.
*/
private final Lock lookupLock = new ReentrantLock();
ValidCachedLookup(String host, InetAddress[] inetAddresses,
long staleTime, long refreshTime)
{
super(host, inetAddresses, staleTime);
this.refreshTime = refreshTime;
this.staleTime = staleTime;
}
@Override
public InetAddress[] get() {
long now = System.nanoTime();
if ((refreshTime - now) < 0L && lookupLock.tryLock()) {
try {
// cachePolicy is in [s] - we need [ns]
refreshTime = now + InetAddressCachePolicy.get() * 1000_000_000L;
// getAddressesFromNameService returns non-empty/non-null value
inetAddresses = getAddressesFromNameService(host);
// don't update the "expirySet", will do that later
staleTime = refreshTime + InetAddressCachePolicy.getStale() * 1000_000_000L;
} catch (UnknownHostException ignore) {
} finally {
lookupLock.unlock();
}
}
return inetAddresses;
}
/**
* Overrides the parent method to skip deleting the record from the
* cache if the stale data can still be used. Note to update the
* "expiryTime" field we have to remove the record from the expirySet
* and add it back. It is not necessary to remove/add it here, we can do
* that in the "get()" method above, but extracting it minimizes
* contention on "expirySet".
*/
@Override
public boolean tryRemoveExpiredAddress(long now) {
// compare difference of time instants rather than
// time instants directly, to avoid possible overflow.
// (see System.nanoTime() recommendations...)
if ((expiryTime - now) < 0L) {
if ((staleTime - now) < 0L) {
return super.tryRemoveExpiredAddress(now);
}
// ConcurrentSkipListSet uses weakly consistent iterator,
// so removing while iterating is OK...
if (expirySet.remove(this)) {
expiryTime = staleTime;
expirySet.add(this);
}
}
return false;
}
}
// a name service lookup based Addresses implementation which replaces itself
// in cache when the result is obtained
private static final class NameServiceAddresses implements Addresses {
private final String host;
private final ReentrantLock lookupLock = new ReentrantLock();
NameServiceAddresses(String host) {
this.host = host;
}
@Override
public InetAddress[] get() throws UnknownHostException {
Addresses addresses;
// only one thread is doing lookup to name service
// for particular host at any time.
lookupLock.lock();
try {
// re-check that we are still us + re-install us if slot empty
addresses = cache.putIfAbsent(host, this);
if (addresses == null) {
// this can happen when we were replaced by CachedAddresses in
// some other thread, then CachedAddresses expired and were
// removed from cache while we were waiting for lock...
addresses = this;
}
// still us ?
if (addresses == this) {
// lookup name services
InetAddress[] inetAddresses;
UnknownHostException ex;
int cachePolicy;
try {
inetAddresses = getAddressesFromNameService(host);
ex = null;
cachePolicy = InetAddressCachePolicy.get();
} catch (UnknownHostException uhe) {
inetAddresses = null;
ex = uhe;
cachePolicy = InetAddressCachePolicy.getNegative();
}
// remove or replace us with cached addresses according to cachePolicy
if (cachePolicy == InetAddressCachePolicy.NEVER) {
cache.remove(host, this);
} else {
long now = System.nanoTime();
long expiryTime =
cachePolicy == InetAddressCachePolicy.FOREVER ?
0L
// cachePolicy is in [s] - we need [ns]
: now + 1000_000_000L * cachePolicy;
CachedLookup cachedLookup;
if (InetAddressCachePolicy.getStale() > 0 &&
ex == null && expiryTime > 0)
{
long refreshTime = expiryTime;
// staleCachePolicy is in [s] - we need [ns]
expiryTime = refreshTime + 1000_000_000L *
InetAddressCachePolicy.getStale();
cachedLookup = new ValidCachedLookup(host,
inetAddresses,
expiryTime,
refreshTime);
} else {
cachedLookup = new CachedLookup(host,
inetAddresses,
expiryTime);
}
if (cache.replace(host, this, cachedLookup) &&
cachePolicy != InetAddressCachePolicy.FOREVER) {
// schedule expiry
expirySet.add(cachedLookup);
}
}
if (inetAddresses == null || inetAddresses.length == 0) {
throw ex == null
? new UnknownHostException(formatMsg("%s", filterNonSocketInfo(host)))
: ex;
}
return inetAddresses;
}
// else addresses != this
} finally {
lookupLock.unlock();
}
// delegate to different addresses when we are already replaced
// but outside of synchronized block to avoid any chance of dead-locking
return addresses.get();
}
}
/**
* The default InetAddressResolver implementation, which delegates to the underlying
* OS network libraries to resolve host address mappings.
*
* @since 9
*/
private static final class PlatformResolver implements InetAddressResolver {
public Stream lookupByName(String host, LookupPolicy policy)
throws UnknownHostException {
Objects.requireNonNull(host);
Objects.requireNonNull(policy);
validate(host);
InetAddress[] addrs;
boolean attempted = Blocker.begin();
try {
addrs = impl.lookupAllHostAddr(host, policy);
} finally {
Blocker.end(attempted);
}
return Arrays.stream(addrs);
}
public String lookupByAddress(byte[] addr) throws UnknownHostException {
Objects.requireNonNull(addr);
if (addr.length != Inet4Address.INADDRSZ && addr.length != Inet6Address.INADDRSZ) {
throw new IllegalArgumentException("Invalid address length");
}
boolean attempted = Blocker.begin();
try {
return impl.getHostByAddr(addr);
} finally {
Blocker.end(attempted);
}
}
}
/**
* The HostsFileResolver provides host address mapping
* by reading the entries in a hosts file, which is specified by
* {@code jdk.net.hosts.file} system property
*
* The file format is that which corresponds with the /etc/hosts file
* IP Address host alias list.
*
*
When the file lookup is enabled it replaces the default InetAddressResolver
* implementation
*
* @since 9
*/
private static final class HostsFileResolver implements InetAddressResolver {
private final String hostsFile;
public HostsFileResolver(String hostsFileName) {
this.hostsFile = hostsFileName;
}
/**
* Lookup the host name corresponding to the IP address provided.
* Search the configured host file a host name corresponding to
* the specified IP address.
*
* @param addr byte array representing an IP address
* @return {@code String} representing the host name mapping
* @throws UnknownHostException if no host found for the specified IP address
* @throws IllegalArgumentException if IP address is of illegal length
* @throws NullPointerException if addr is {@code null}
*/
@Override
public String lookupByAddress(byte[] addr) throws UnknownHostException {
String hostEntry;
String host = null;
Objects.requireNonNull(addr);
// Check the length of the address array
if (addr.length != Inet4Address.INADDRSZ && addr.length != Inet6Address.INADDRSZ) {
throw new IllegalArgumentException("Invalid address length");
}
try (Scanner hostsFileScanner = new Scanner(new File(hostsFile),
UTF_8.INSTANCE)) {
while (hostsFileScanner.hasNextLine()) {
hostEntry = hostsFileScanner.nextLine();
if (!hostEntry.startsWith("#")) {
hostEntry = removeComments(hostEntry);
String[] mapping = hostEntry.split("\\s+");
if (mapping.length >= 2 &&
Arrays.equals(addr, createAddressByteArray(mapping[0]))) {
host = mapping[1];
break;
}
}
}
} catch (IOException e) {
throw new UnknownHostException(
formatMsg("Unable to resolve address %s as hosts file %s not found",
filterNonSocketInfo(Arrays.toString(addr)),
filterNonSocketInfo(hostsFile)
.replaceWith("from ${jdk.net.hosts.file} system property")));
}
if ((host == null) || (host.isEmpty()) || (host.equals(" "))) {
throw new UnknownHostException(
formatMsg("Requested address %s resolves to an invalid entry in hosts file %s",
filterNonSocketInfo(Arrays.toString(addr)),
filterNonSocketInfo(hostsFile)
.replaceWith("from ${jdk.net.hosts.file} system property")));
}
return host;
}
/**
*
Lookup a host mapping by name. Retrieve the IP addresses
* associated with a host.
*
*
Search the configured hosts file for the addresses associated
* with the specified host name.
*
* @param host the specified hostname
* @param lookupPolicy IP addresses lookup policy which specifies addresses
* family and their order
* @return stream of IP addresses for the requested host
* @throws NullPointerException if either parameter is {@code null}
* @throws UnknownHostException
* if no IP address for the {@code host} could be found
*/
public Stream lookupByName(String host, LookupPolicy lookupPolicy)
throws UnknownHostException {
String hostEntry;
String addrStr;
byte addr[];
Objects.requireNonNull(host);
Objects.requireNonNull(lookupPolicy);
List inetAddresses = new ArrayList<>();
List inet4Addresses = new ArrayList<>();
List inet6Addresses = new ArrayList<>();
int flags = lookupPolicy.characteristics();
boolean needIPv4 = (flags & IPv4) != 0;
boolean needIPv6 = (flags & IPv6) != 0;
// lookup the file and create a list InetAddress for the specified host
try (Scanner hostsFileScanner = new Scanner(new File(hostsFile),
UTF_8.INSTANCE)) {
while (hostsFileScanner.hasNextLine()) {
hostEntry = hostsFileScanner.nextLine();
if (!hostEntry.startsWith("#")) {
hostEntry = removeComments(hostEntry);
if (hostEntry.contains(host)) {
addrStr = extractHostAddr(hostEntry, host);
if ((addrStr != null) && (!addrStr.isEmpty())) {
addr = createAddressByteArray(addrStr);
if (addr != null) {
InetAddress address = InetAddress.getByAddress(host, addr);
inetAddresses.add(address);
if (address instanceof Inet4Address && needIPv4) {
inet4Addresses.add(address);
}
if (address instanceof Inet6Address && needIPv6) {
inet6Addresses.add(address);
}
}
}
}
}
}
} catch (IOException e) {
throw new UnknownHostException(
formatMsg("Unable to resolve host %s as hosts file %s not found",
filterNonSocketInfo(host), filterNonSocketInfo(hostsFile)
.replaceWith("from ${jdk.net.hosts.file} system property")));
}
// Check if only IPv4 addresses are requested
if (needIPv4 && !needIPv6) {
checkResultsList(inet4Addresses, host);
return inet4Addresses.stream();
}
// Check if only IPv6 addresses are requested
if (!needIPv4 && needIPv6) {
checkResultsList(inet6Addresses, host);
return inet6Addresses.stream();
}
// If both type of addresses are requested:
// First, check if there is any results. Then arrange
// addresses according to LookupPolicy value.
checkResultsList(inetAddresses, host);
if (ipv6AddressesFirst(flags)) {
return Stream.concat(inet6Addresses.stream(), inet4Addresses.stream());
} else if (ipv4AddressesFirst(flags)) {
return Stream.concat(inet4Addresses.stream(), inet6Addresses.stream());
}
// Only "system" addresses order is possible at this stage
assert systemAddressesOrder(flags);
return inetAddresses.stream();
}
// Checks if result list with addresses is not empty.
// If it is empty throw an UnknownHostException.
private void checkResultsList(List addressesList, String hostName)
throws UnknownHostException {
if (addressesList.isEmpty()) {
throw new UnknownHostException(
formatMsg("Unable to resolve host %s in hosts file %s",
filterNonSocketInfo(hostName), filterNonSocketInfo(hostsFile)
.replaceWith("from ${jdk.net.hosts.file} system property")));
}
}
private String removeComments(String hostsEntry) {
String filteredEntry = hostsEntry;
int hashIndex;
if ((hashIndex = hostsEntry.indexOf("#")) != -1) {
filteredEntry = hostsEntry.substring(0, hashIndex);
}
return filteredEntry;
}
private byte [] createAddressByteArray(String addrStr) {
byte[] addrArray;
// check if IPV4 address - most likely
try {
addrArray = IPAddressUtil.validateNumericFormatV4(addrStr, false);
} catch (IllegalArgumentException iae) {
return null;
}
if (addrArray == null) {
addrArray = IPAddressUtil.textToNumericFormatV6(addrStr);
}
return addrArray;
}
/** host to ip address mapping */
private String extractHostAddr(String hostEntry, String host) {
String[] mapping = hostEntry.split("\\s+");
String hostAddr = null;
if (mapping.length >= 2) {
// look at the host aliases
for (int i = 1; i < mapping.length; i++) {
if (mapping[i].equalsIgnoreCase(host)) {
hostAddr = mapping[0];
}
}
}
return hostAddr;
}
}
static final InetAddressImpl impl;
/**
* Platform-wide {@code LookupPolicy} initialized from {@code "java.net.preferIPv4Stack"},
* {@code "java.net.preferIPv6Addresses"} system properties.
*/
static final LookupPolicy PLATFORM_LOOKUP_POLICY;
static {
// create the impl
impl = isIPv6Supported() ?
new Inet6AddressImpl() : new Inet4AddressImpl();
// impl must be initialized before calling this method
PLATFORM_LOOKUP_POLICY = initializePlatformLookupPolicy();
// create built-in resolver
BUILTIN_RESOLVER = createBuiltinInetAddressResolver();
}
/**
* Create an instance of the InetAddressResolver interface based on
* the setting of the {@code jdk.net.hosts.file} system property.
*
* The default InetAddressResolver is the PlatformResolver, which typically
* delegates name and address resolution calls to the underlying
* OS network libraries.
*
*
A HostsFileResolver is created if the {@code jdk.net.hosts.file}
* system property is set. If the specified file doesn't exist, the name or
* address lookup will result in an UnknownHostException. Thus, non existent
* hosts file is handled as if the file is empty.
*
* @return an InetAddressResolver
*/
private static InetAddressResolver createBuiltinInetAddressResolver() {
InetAddressResolver theResolver;
if (HOSTS_FILE_NAME != null) {
theResolver = new HostsFileResolver(HOSTS_FILE_NAME);
} else {
theResolver = new PlatformResolver();
}
return theResolver;
}
/**
* Creates an InetAddress based on the provided host name and IP address.
* The system-wide {@linkplain InetAddressResolver resolver} is not used to check
* the validity of the address.
*
*
The host name can either be a machine name, such as
* "{@code www.example.com}", or a textual representation of its IP
* address.
*
No validity checking is done on the host name either.
*
*
If addr specifies an IPv4 address an instance of Inet4Address
* will be returned; otherwise, an instance of Inet6Address
* will be returned.
*
*
IPv4 address byte array must be 4 bytes long and IPv6 byte array
* must be 16 bytes long
*
* @param host the specified host
* @param addr the raw IP address in network byte order
* @return an InetAddress object created from the raw IP address.
* @throws UnknownHostException if IP address is of illegal length
* @since 1.4
*/
public static InetAddress getByAddress(String host, byte[] addr)
throws UnknownHostException {
if (host != null && !host.isEmpty() && host.charAt(0) == '[') {
if (host.charAt(host.length()-1) == ']') {
host = host.substring(1, host.length() -1);
}
}
if (addr != null) {
if (addr.length == Inet4Address.INADDRSZ) {
return new Inet4Address(host, addr);
} else if (addr.length == Inet6Address.INADDRSZ) {
byte[] newAddr
= IPAddressUtil.convertFromIPv4MappedAddress(addr);
if (newAddr != null) {
return new Inet4Address(host, newAddr);
} else {
return new Inet6Address(host, addr);
}
}
}
throw new UnknownHostException("addr is of illegal length");
}
/**
* Determines the IP address of a host, given the host's name.
*
*
The host name can either be a machine name, such as
* "{@code www.example.com}", or a textual representation of its
* IP address. If a literal IP address is supplied, only the
* validity of the address format is checked.
*
*
For {@code host} specified in literal IPv6 address,
* either the form defined in RFC 2732 or the literal IPv6 address
* format defined in RFC 2373 is accepted. IPv6 scoped addresses are also
* supported. See here for a description of IPv6
* scoped addresses.
*
*
If the host is {@code null} or {@code host.length()} is equal
* to zero, then an {@code InetAddress} representing an address of the
* loopback interface is returned.
* See RFC 3330
* section 2 and RFC 2373
* section 2.5.3.
*
* @param host the specified host, or {@code null}.
* @return an IP address for the given host name.
* @throws UnknownHostException if no IP address for the
* {@code host} could be found, or if a scope_id was specified
* for a global IPv6 address.
*
* @spec https://www.rfc-editor.org/info/rfc2373 RFC 2373: IP Version 6 Addressing Architecture
* @spec https://www.rfc-editor.org/info/rfc3330 RFC 3330: Special-Use IPv4 Addresses
*/
public static InetAddress getByName(String host)
throws UnknownHostException {
return InetAddress.getAllByName(host)[0];
}
/**
* Given the name of a host, returns an array of its IP addresses,
* based on the system-wide {@linkplain InetAddressResolver resolver}.
*
*
The host name can either be a machine name, such as
* "{@code www.example.com}", or a textual representation of its IP
* address. If a literal IP address is supplied, only the
* validity of the address format is checked.
*
*
For {@code host} specified in literal IPv6 address,
* either the form defined in RFC 2732 or the literal IPv6 address
* format defined in RFC 2373 is accepted. A literal IPv6 address may
* also be qualified by appending a scoped zone identifier or scope_id.
* The syntax and usage of scope_ids is described
* here.
*
*
If the host is {@code null} or {@code host.length()} is equal
* to zero, then an {@code InetAddress} representing an address of the
* loopback interface is returned.
* See RFC 3330
* section 2 and RFC 2373
* section 2.5.3.
*
* @param host the name of the host, or {@code null}.
* @return an array of all the IP addresses for a given host name.
*
* @throws UnknownHostException if no IP address for the
* {@code host} could be found, or if a scope_id was specified
* for a global IPv6 address.
*
* @spec https://www.rfc-editor.org/info/rfc2373 RFC 2373: IP Version 6 Addressing Architecture
* @spec https://www.rfc-editor.org/info/rfc3330 RFC 3330: Special-Use IPv4 Addresses
*/
public static InetAddress[] getAllByName(String host)
throws UnknownHostException {
if (host == null || host.isEmpty()) {
InetAddress[] ret = new InetAddress[1];
ret[0] = impl.loopbackAddress();
return ret;
}
validate(host);
boolean ipv6Expected = false;
if (host.charAt(0) == '[') {
// This is supposed to be an IPv6 literal
if (host.length() > 2 && host.charAt(host.length()-1) == ']') {
host = host.substring(1, host.length() -1);
ipv6Expected = true;
} else {
// This was supposed to be a IPv6 literal, but it's not
throw invalidIPv6LiteralException(host, false);
}
}
// Check and try to parse host string as an IP address literal
if (IPAddressUtil.digit(host.charAt(0), 16) != -1
|| (host.charAt(0) == ':')) {
InetAddress inetAddress = null;
if (!ipv6Expected) {
// check if it is IPv4 address only if host is not wrapped in '[]'
try {
// Here we check the address string for ambiguity only
inetAddress = Inet4Address.parseAddressString(host, false);
} catch (IllegalArgumentException iae) {
var uhe = new UnknownHostException(formatMsg("%s", filterNonSocketInfo(host)));
uhe.initCause(iae);
throw uhe;
}
}
if (inetAddress == null) {
// This is supposed to be an IPv6 literal
// Check for presence of a numeric or string zone id
// is done in Inet6Address.parseAddressString
if ((inetAddress = Inet6Address.parseAddressString(host, false)) == null &&
(host.contains(":") || ipv6Expected)) {
throw invalidIPv6LiteralException(host, ipv6Expected);
}
}
if (inetAddress != null) {
return new InetAddress[]{inetAddress};
}
} else if (ipv6Expected) {
// We were expecting an IPv6 Literal since host string starts
// and ends with square brackets, but we got something else.
throw invalidIPv6LiteralException(host, true);
}
return getAllByName0(host, true);
}
private static UnknownHostException invalidIPv6LiteralException(String host, boolean wrapInBrackets) {
String hostString = wrapInBrackets ? "[" + host + "]" : host;
return new UnknownHostException(formatMsg("%sinvalid IPv6 address literal",
filterNonSocketInfo(hostString).suffixWith(": ")));
}
/**
* Returns the loopback address.
*
* The InetAddress returned will represent the IPv4
* loopback address, 127.0.0.1, or the IPv6 loopback
* address, ::1. The IPv4 loopback address returned
* is only one of many in the form 127.*.*.*
*
* @return the InetAddress loopback instance.
* @since 1.7
*/
public static InetAddress getLoopbackAddress() {
return impl.loopbackAddress();
}
/**
* package private so SocketPermission can call it
*/
static InetAddress[] getAllByName0(String host) throws UnknownHostException {
return getAllByName0(host, true);
}
/**
* Creates an {@code InetAddress} based on the provided {@linkplain InetAddress##format
* textual representation} of an IP address.
*
The provided IP address literal is parsed as
* {@linkplain Inet4Address#ofLiteral(String) an IPv4 address literal} first.
* If it cannot be parsed as an IPv4 address literal, then the method attempts
* to parse it as {@linkplain Inet6Address#ofLiteral(String) an IPv6 address literal}.
* If neither attempts succeed an {@code IllegalArgumentException} is thrown.
*
This method doesn't block, i.e. no reverse lookup is performed.
*
* @param ipAddressLiteral the textual representation of an IP address.
* @return an {@link InetAddress} object with no hostname set, and constructed
* from the provided IP address literal.
* @throws IllegalArgumentException if the {@code ipAddressLiteral} cannot be parsed
* as an IPv4 or IPv6 address literal.
* @throws NullPointerException if the {@code ipAddressLiteral} is {@code null}.
* @see Inet4Address#ofLiteral(String)
* @see Inet6Address#ofLiteral(String)
* @see Inet4Address#ofPosixLiteral(String)
* @since 22
*/
public static InetAddress ofLiteral(String ipAddressLiteral) {
Objects.requireNonNull(ipAddressLiteral);
if (ipAddressLiteral.isEmpty()) {
throw IPAddressUtil.invalidIpAddressLiteral(ipAddressLiteral);
}
InetAddress inetAddress;
try {
// First try to parse the input as an IPv4 address literal
inetAddress = Inet4Address.ofLiteral(ipAddressLiteral);
} catch (IllegalArgumentException iae) {
// If it fails try to parse the input as an IPv6 address literal
inetAddress = Inet6Address.ofLiteral(ipAddressLiteral);
}
return inetAddress;
}
/**
* Designated lookup method.
*
* @param host host name to look up
* @param useCache use cached value if not expired else always
* perform name service lookup (and cache the result)
* @return array of InetAddress(es)
* @throws UnknownHostException if host name is not found
*/
private static InetAddress[] getAllByName0(String host,
boolean useCache)
throws UnknownHostException {
/* If it gets here it is presumed to be a hostname */
// remove expired addresses from cache - expirySet keeps them ordered
// by expiry time so we only need to iterate the prefix of the NavigableSet...
long now = System.nanoTime();
for (CachedLookup caddrs : expirySet) {
if (!caddrs.tryRemoveExpiredAddress(now)) {
// we encountered 1st element that expires in future
break;
}
}
// look-up or remove from cache
Addresses addrs;
if (useCache) {
addrs = cache.get(host);
} else {
addrs = cache.remove(host);
if (addrs != null) {
if (addrs instanceof CachedLookup) {
// try removing from expirySet too if CachedAddresses
expirySet.remove(addrs);
}
addrs = null;
}
}
if (addrs == null) {
// create a NameServiceAddresses instance which will look up
// the name service and install it within cache...
Addresses oldAddrs = cache.putIfAbsent(
host,
addrs = new NameServiceAddresses(host)
);
if (oldAddrs != null) { // lost putIfAbsent race
addrs = oldAddrs;
}
}
// ask Addresses to get an array of InetAddress(es) and clone it
return addrs.get().clone();
}
static InetAddress[] getAddressesFromNameService(String host)
throws UnknownHostException {
Stream addresses = null;
UnknownHostException ex = null;
var resolver = resolver();
try {
addresses = resolver.lookupByName(host, PLATFORM_LOOKUP_POLICY);
} catch (RuntimeException | UnknownHostException x) {
if (host.equalsIgnoreCase("localhost")) {
addresses = Stream.of(impl.loopbackAddress());
} else if (x instanceof UnknownHostException uhe) {
ex = uhe;
} else {
ex = new UnknownHostException();
ex.initCause(x);
}
}
InetAddress[] result = addresses == null ? null
: addresses.toArray(InetAddress[]::new);
if (result == null || result.length == 0) {
throw ex == null ? new UnknownHostException(formatMsg("%s", filterNonSocketInfo(host)))
: ex;
}
return result;
}
/**
* Returns an {@code InetAddress} object given the raw IP address .
* The argument is in network byte order: the highest order
* byte of the address is in {@code getAddress()[0]}.
*
* This method doesn't block, i.e. no reverse lookup is performed.
*
*
IPv4 address byte array must be 4 bytes long and IPv6 byte array
* must be 16 bytes long
*
* @param addr the raw IP address in network byte order
* @return an InetAddress object created from the raw IP address.
* @throws UnknownHostException if IP address is of illegal length
* @since 1.4
*/
public static InetAddress getByAddress(byte[] addr)
throws UnknownHostException {
return getByAddress(null, addr);
}
private static final class CachedLocalHost {
final String host;
final InetAddress addr;
final long expiryTime = System.nanoTime() + 5000_000_000L; // now + 5s;
CachedLocalHost(String host, InetAddress addr) {
this.host = host;
this.addr = addr;
}
}
private static volatile CachedLocalHost cachedLocalHost;
/**
* Returns the address of the local host. This is achieved by retrieving
* the name of the host from the system, then resolving that name into
* an {@code InetAddress}.
*
*
Note: The resolved address may be cached for a short period of time.
*
*
* @return the address of the local host.
*
* @throws UnknownHostException if the local host name could not
* be resolved into an address.
*
* @see java.net.InetAddress#getByName(java.lang.String)
*/
public static InetAddress getLocalHost() throws UnknownHostException {
// is cached data still valid?
CachedLocalHost clh = cachedLocalHost;
if (clh != null && (clh.expiryTime - System.nanoTime()) >= 0L) {
return clh.addr;
}
String local = impl.getLocalHostName();
InetAddress localAddr;
if (local.equals("localhost")) {
// shortcut for "localhost" host name
localAddr = impl.loopbackAddress();
} else {
// call getAllByName0 without using cached data
try {
localAddr = getAllByName0(local, false)[0];
} catch (UnknownHostException uhe) {
// Rethrow with a more informative error message.
UnknownHostException uhe2 =
new UnknownHostException(formatMsg(filterNonSocketInfo(local)
.suffixWith(": ") + uhe.getMessage()));
uhe2.initCause(uhe);
throw uhe2;
}
}
cachedLocalHost = new CachedLocalHost(local, localAddr);
return localAddr;
}
/**
* Perform class load-time initializations.
*/
private static native void init();
/*
* Returns the InetAddress representing anyLocalAddress
* (typically 0.0.0.0 or ::0)
*/
static InetAddress anyLocalAddress() {
return impl.anyLocalAddress();
}
private static final jdk.internal.misc.Unsafe UNSAFE
= jdk.internal.misc.Unsafe.getUnsafe();
private static final long FIELDS_OFFSET
= UNSAFE.objectFieldOffset(InetAddress.class, "holder");
/**
* Restores the state of this object from the stream.
*
* @param s the {@code ObjectInputStream} from which data is read
* @throws IOException if an I/O error occurs
* @throws ClassNotFoundException if a serialized class cannot be loaded
*/
@java.io.Serial
private void readObject (ObjectInputStream s) throws
IOException, ClassNotFoundException {
GetField gf = s.readFields();
String host = (String)gf.get("hostName", null);
int address = gf.get("address", 0);
int family = gf.get("family", 0);
if (family != IPv4 && family != IPv6) {
throw new InvalidObjectException("invalid address family type: " + family);
}
InetAddressHolder h = new InetAddressHolder(host, address, family);
UNSAFE.putReference(this, FIELDS_OFFSET, h);
}
/* needed because the serializable fields no longer exist */
/**
* @serialField hostName String the hostname for this address
* @serialField address int holds a 32-bit IPv4 address.
* @serialField family int specifies the address family type, for instance,
* {@code '1'} for IPv4 addresses, and {@code '2'} for IPv6 addresses.
*/
@java.io.Serial
private static final ObjectStreamField[] serialPersistentFields = {
new ObjectStreamField("hostName", String.class),
new ObjectStreamField("address", int.class),
new ObjectStreamField("family", int.class),
};
/**
* Writes the state of this object to the stream.
*
* @param s the {@code ObjectOutputStream} to which data is written
* @throws IOException if an I/O error occurs
*/
@java.io.Serial
private void writeObject (ObjectOutputStream s) throws IOException {
PutField pf = s.putFields();
pf.put("hostName", holder().getHostName());
pf.put("address", holder().getAddress());
pf.put("family", holder().getFamily());
s.writeFields();
}
private static void validate(String host) throws UnknownHostException {
if (host.indexOf(0) != -1) {
throw new UnknownHostException("NUL character not allowed in hostname");
}
}
}