Java tutorial
/* * Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.net; import java.io.IOException; import java.io.InvalidObjectException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.io.ObjectStreamField; import java.util.Enumeration; import java.util.Arrays; /** * This class represents an Internet Protocol version 6 (IPv6) address. * Defined by <a href="http://www.ietf.org/rfc/rfc2373.txt"> * <i>RFC 2373: IP Version 6 Addressing Architecture</i></a>. * * <h2> <a id="format">Textual representation of IP addresses</a> </h2> * * Textual representation of IPv6 address used as input to methods * takes one of the following forms: * * <ol> * <li><p> <a id="lform">The preferred form</a> is x:x:x:x:x:x:x:x, * where the 'x's are * the hexadecimal values of the eight 16-bit pieces of the * address. This is the full form. For example, * * <blockquote><ul style="list-style-type:none"> * <li>{@code 1080:0:0:0:8:800:200C:417A}</li> * </ul></blockquote> * * <p> Note that it is not necessary to write the leading zeros in * an individual field. However, there must be at least one numeral * in every field, except as described below.</li> * * <li><p> Due to some methods of allocating certain styles of IPv6 * addresses, it will be common for addresses to contain long * strings of zero bits. In order to make writing addresses * containing zero bits easier, a special syntax is available to * compress the zeros. The use of "::" indicates multiple groups * of 16-bits of zeros. The "::" can only appear once in an address. * The "::" can also be used to compress the leading and/or trailing * zeros in an address. For example, * * <blockquote><ul style="list-style-type:none"> * <li>{@code 1080::8:800:200C:417A}</li> * </ul></blockquote> * * <li><p> An alternative form that is sometimes more convenient * when dealing with a mixed environment of IPv4 and IPv6 nodes is * x:x:x:x:x:x:d.d.d.d, where the 'x's are the hexadecimal values * of the six high-order 16-bit pieces of the address, and the 'd's * are the decimal values of the four low-order 8-bit pieces of the * standard IPv4 representation address, for example, * * <blockquote><ul style="list-style-type:none"> * <li>{@code ::FFFF:129.144.52.38}</li> * <li>{@code ::129.144.52.38}</li> * </ul></blockquote> * * <p> where "::FFFF:d.d.d.d" and "::d.d.d.d" are, respectively, the * general forms of an IPv4-mapped IPv6 address and an * IPv4-compatible IPv6 address. Note that the IPv4 portion must be * in the "d.d.d.d" form. The following forms are invalid: * * <blockquote><ul style="list-style-type:none"> * <li>{@code ::FFFF:d.d.d}</li> * <li>{@code ::FFFF:d.d}</li> * <li>{@code ::d.d.d}</li> * <li>{@code ::d.d}</li> * </ul></blockquote> * * <p> The following form: * * <blockquote><ul style="list-style-type:none"> * <li>{@code ::FFFF:d}</li> * </ul></blockquote> * * <p> is valid, however it is an unconventional representation of * the IPv4-compatible IPv6 address, * * <blockquote><ul style="list-style-type:none"> * <li>{@code ::255.255.0.d}</li> * </ul></blockquote> * * <p> while "::d" corresponds to the general IPv6 address * "0:0:0:0:0:0:0:d".</li> * </ol> * * <p> For methods that return a textual representation as output * value, the full form is used. Inet6Address will return the full * form because it is unambiguous when used in combination with other * textual data. * * <h3> Special IPv6 address </h3> * * <blockquote> * <table class="borderless"> * <caption style="display:none">Description of IPv4-mapped address</caption> * <tr><th style="vertical-align:top; padding-right:2px"><i>IPv4-mapped address</i></th> * <td>Of the form ::ffff:w.x.y.z, this IPv6 address is used to * represent an IPv4 address. It allows the native program to * use the same address data structure and also the same * socket when communicating with both IPv4 and IPv6 nodes. * * <p>In InetAddress and Inet6Address, it is used for internal * representation; it has no functional role. Java will never * return an IPv4-mapped address. These classes can take an * IPv4-mapped address as input, both in byte array and text * representation. However, it will be converted into an IPv4 * address.</td></tr> * </table></blockquote> * * <h3><a id="scoped">Textual representation of IPv6 scoped addresses</a></h3> * * <p> The textual representation of IPv6 addresses as described above can be * extended to specify IPv6 scoped addresses. This extension to the basic * addressing architecture is described in [draft-ietf-ipngwg-scoping-arch-04.txt]. * * <p> Because link-local and site-local addresses are non-global, it is possible * that different hosts may have the same destination address and may be * reachable through different interfaces on the same originating system. In * this case, the originating system is said to be connected to multiple zones * of the same scope. In order to disambiguate which is the intended destination * zone, it is possible to append a zone identifier (or <i>scope_id</i>) to an * IPv6 address. * * <p> The general format for specifying the <i>scope_id</i> is the following: * * <blockquote><i>IPv6-address</i>%<i>scope_id</i></blockquote> * <p> The IPv6-address is a literal IPv6 address as described above. * The <i>scope_id</i> refers to an interface on the local system, and it can be * specified in two ways. * <ol><li><i>As a numeric identifier.</i> This must be a positive integer * that identifies the particular interface and scope as understood by the * system. Usually, the numeric values can be determined through administration * tools on the system. Each interface may have multiple values, one for each * scope. If the scope is unspecified, then the default value used is zero.</li> * <li><i>As a string.</i> This must be the exact string that is returned by * {@link java.net.NetworkInterface#getName()} for the particular interface in * question. When an Inet6Address is created in this way, the numeric scope-id * is determined at the time the object is created by querying the relevant * NetworkInterface.</li></ol> * * <p> Note also, that the numeric <i>scope_id</i> can be retrieved from * Inet6Address instances returned from the NetworkInterface class. This can be * used to find out the current scope ids configured on the system. * @since 1.4 */ public final class Inet6Address extends InetAddress { static final int INADDRSZ = 16; private class Inet6AddressHolder { private Inet6AddressHolder() { ipaddress = new byte[INADDRSZ]; } private Inet6AddressHolder(byte[] ipaddress, int scope_id, boolean scope_id_set, NetworkInterface ifname, boolean scope_ifname_set) { this.ipaddress = ipaddress; this.scope_id = scope_id; this.scope_id_set = scope_id_set; this.scope_ifname_set = scope_ifname_set; this.scope_ifname = ifname; } /** * Holds a 128-bit (16 bytes) IPv6 address. */ byte[] ipaddress; /** * scope_id. The scope specified when the object is created. If the object * is created with an interface name, then the scope_id is not determined * until the time it is needed. */ int scope_id; // 0 /** * This will be set to true when the scope_id field contains a valid * integer scope_id. */ boolean scope_id_set; // false /** * scoped interface. scope_id is derived from this as the scope_id of the first * address whose scope is the same as this address for the named interface. */ NetworkInterface scope_ifname; // null /** * set if the object is constructed with a scoped * interface instead of a numeric scope id. */ boolean scope_ifname_set; // false; void setAddr(byte addr[]) { if (addr.length == INADDRSZ) { // normal IPv6 address System.arraycopy(addr, 0, ipaddress, 0, INADDRSZ); } } void init(byte addr[], int scope_id) { setAddr(addr); if (scope_id >= 0) { this.scope_id = scope_id; this.scope_id_set = true; } } void init(byte addr[], NetworkInterface nif) throws UnknownHostException { setAddr(addr); if (nif != null) { this.scope_id = deriveNumericScope(ipaddress, nif); this.scope_id_set = true; this.scope_ifname = nif; this.scope_ifname_set = true; } } String getHostAddress() { String s = numericToTextFormat(ipaddress); if (scope_ifname != null) { /* must check this first */ s = s + "%" + scope_ifname.getName(); } else if (scope_id_set) { s = s + "%" + scope_id; } return s; } public boolean equals(Object o) { if (!(o instanceof Inet6AddressHolder)) { return false; } Inet6AddressHolder that = (Inet6AddressHolder) o; return Arrays.equals(this.ipaddress, that.ipaddress); } public int hashCode() { if (ipaddress != null) { int hash = 0; int i = 0; while (i < INADDRSZ) { int j = 0; int component = 0; while (j < 4 && i < INADDRSZ) { component = (component << 8) + ipaddress[i]; j++; i++; } hash += component; } return hash; } else { return 0; } } boolean isIPv4CompatibleAddress() { if ((ipaddress[0] == 0x00) && (ipaddress[1] == 0x00) && (ipaddress[2] == 0x00) && (ipaddress[3] == 0x00) && (ipaddress[4] == 0x00) && (ipaddress[5] == 0x00) && (ipaddress[6] == 0x00) && (ipaddress[7] == 0x00) && (ipaddress[8] == 0x00) && (ipaddress[9] == 0x00) && (ipaddress[10] == 0x00) && (ipaddress[11] == 0x00)) { return true; } return false; } boolean isMulticastAddress() { return ((ipaddress[0] & 0xff) == 0xff); } boolean isAnyLocalAddress() { byte test = 0x00; for (int i = 0; i < INADDRSZ; i++) { test |= ipaddress[i]; } return (test == 0x00); } boolean isLoopbackAddress() { byte test = 0x00; for (int i = 0; i < 15; i++) { test |= ipaddress[i]; } return (test == 0x00) && (ipaddress[15] == 0x01); } boolean isLinkLocalAddress() { return ((ipaddress[0] & 0xff) == 0xfe && (ipaddress[1] & 0xc0) == 0x80); } boolean isSiteLocalAddress() { return ((ipaddress[0] & 0xff) == 0xfe && (ipaddress[1] & 0xc0) == 0xc0); } boolean isMCGlobal() { return ((ipaddress[0] & 0xff) == 0xff && (ipaddress[1] & 0x0f) == 0x0e); } boolean isMCNodeLocal() { return ((ipaddress[0] & 0xff) == 0xff && (ipaddress[1] & 0x0f) == 0x01); } boolean isMCLinkLocal() { return ((ipaddress[0] & 0xff) == 0xff && (ipaddress[1] & 0x0f) == 0x02); } boolean isMCSiteLocal() { return ((ipaddress[0] & 0xff) == 0xff && (ipaddress[1] & 0x0f) == 0x05); } boolean isMCOrgLocal() { return ((ipaddress[0] & 0xff) == 0xff && (ipaddress[1] & 0x0f) == 0x08); } } private final transient Inet6AddressHolder holder6; private static final long serialVersionUID = 6880410070516793377L; // Perform native initialization static { init(); } Inet6Address() { super(); holder.init(null, IPv6); holder6 = new Inet6AddressHolder(); } /* checking of value for scope_id should be done by caller * scope_id must be >= 0, or -1 to indicate not being set */ Inet6Address(String hostName, byte addr[], int scope_id) { holder.init(hostName, IPv6); holder6 = new Inet6AddressHolder(); holder6.init(addr, scope_id); } Inet6Address(String hostName, byte addr[]) { holder6 = new Inet6AddressHolder(); try { initif(hostName, addr, null); } catch (UnknownHostException e) { } /* cant happen if ifname is null */ } Inet6Address(String hostName, byte addr[], NetworkInterface nif) throws UnknownHostException { holder6 = new Inet6AddressHolder(); initif(hostName, addr, nif); } Inet6Address(String hostName, byte addr[], String ifname) throws UnknownHostException { holder6 = new Inet6AddressHolder(); initstr(hostName, addr, ifname); } /** * Create an Inet6Address in the exact manner of {@link * InetAddress#getByAddress(String,byte[])} except that the IPv6 scope_id is * set to the value corresponding to the given interface for the address * type specified in {@code addr}. The call will fail with an * UnknownHostException if the given interface does not have a numeric * scope_id assigned for the given address type (e.g. link-local or site-local). * See <a href="Inet6Address.html#scoped">here</a> for a description of IPv6 * scoped addresses. * * @param host the specified host * @param addr the raw IP address in network byte order * @param nif an interface this address must be associated with. * @return an Inet6Address object created from the raw IP address. * @throws UnknownHostException * if IP address is of illegal length, or if the interface does not * have a numeric scope_id assigned for the given address type. * * @since 1.5 */ public static Inet6Address getByAddress(String host, byte[] addr, NetworkInterface nif) 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 == Inet6Address.INADDRSZ) { return new Inet6Address(host, addr, nif); } } throw new UnknownHostException("addr is of illegal length"); } /** * Create an Inet6Address in the exact manner of {@link * InetAddress#getByAddress(String,byte[])} except that the IPv6 scope_id is * set to the given numeric value. The scope_id is not checked to determine * if it corresponds to any interface on the system. * See <a href="Inet6Address.html#scoped">here</a> for a description of IPv6 * scoped addresses. * * @param host the specified host * @param addr the raw IP address in network byte order * @param scope_id the numeric scope_id for the address. * @return an Inet6Address object created from the raw IP address. * @throws UnknownHostException if IP address is of illegal length. * * @since 1.5 */ public static Inet6Address getByAddress(String host, byte[] addr, int scope_id) 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 == Inet6Address.INADDRSZ) { return new Inet6Address(host, addr, scope_id); } } throw new UnknownHostException("addr is of illegal length"); } private void initstr(String hostName, byte addr[], String ifname) throws UnknownHostException { try { NetworkInterface nif = NetworkInterface.getByName(ifname); if (nif == null) { throw new UnknownHostException("no such interface " + ifname); } initif(hostName, addr, nif); } catch (SocketException e) { throw new UnknownHostException("SocketException thrown" + ifname); } } private void initif(String hostName, byte addr[], NetworkInterface nif) throws UnknownHostException { int family = -1; holder6.init(addr, nif); if (addr.length == INADDRSZ) { // normal IPv6 address family = IPv6; } holder.init(hostName, family); } /* check the two Ipv6 addresses and return false if they are both * non global address types, but not the same. * (i.e. one is site-local and the other link-local) * return true otherwise. */ private static boolean isDifferentLocalAddressType(byte[] thisAddr, byte[] otherAddr) { if (Inet6Address.isLinkLocalAddress(thisAddr) && !Inet6Address.isLinkLocalAddress(otherAddr)) { return false; } if (Inet6Address.isSiteLocalAddress(thisAddr) && !Inet6Address.isSiteLocalAddress(otherAddr)) { return false; } return true; } private static int deriveNumericScope(byte[] thisAddr, NetworkInterface ifc) throws UnknownHostException { Enumeration<InetAddress> addresses = ifc.getInetAddresses(); while (addresses.hasMoreElements()) { InetAddress addr = addresses.nextElement(); if (!(addr instanceof Inet6Address)) { continue; } Inet6Address ia6_addr = (Inet6Address) addr; /* check if site or link local prefixes match */ if (!isDifferentLocalAddressType(thisAddr, ia6_addr.getAddress())) { /* type not the same, so carry on searching */ continue; } /* found a matching address - return its scope_id */ return ia6_addr.getScopeId(); } throw new UnknownHostException("no scope_id found"); } private int deriveNumericScope(String ifname) throws UnknownHostException { Enumeration<NetworkInterface> en; try { en = NetworkInterface.getNetworkInterfaces(); } catch (SocketException e) { throw new UnknownHostException("could not enumerate local network interfaces"); } while (en.hasMoreElements()) { NetworkInterface ifc = en.nextElement(); if (ifc.getName().equals(ifname)) { return deriveNumericScope(holder6.ipaddress, ifc); } } throw new UnknownHostException("No matching address found for interface : " + ifname); } /** * @serialField ipaddress byte[] * @serialField scope_id int * @serialField scope_id_set boolean * @serialField scope_ifname_set boolean * @serialField ifname String */ private static final ObjectStreamField[] serialPersistentFields = { new ObjectStreamField("ipaddress", byte[].class), new ObjectStreamField("scope_id", int.class), new ObjectStreamField("scope_id_set", boolean.class), new ObjectStreamField("scope_ifname_set", boolean.class), new ObjectStreamField("ifname", String.class) }; private static final jdk.internal.misc.Unsafe UNSAFE = jdk.internal.misc.Unsafe.getUnsafe(); private static final long FIELDS_OFFSET = UNSAFE.objectFieldOffset(Inet6Address.class, "holder6"); /** * restore the state of this object from stream * including the scope information, only if the * scoped interface name is valid on this system */ private void readObject(ObjectInputStream s) throws IOException, ClassNotFoundException { NetworkInterface scope_ifname = null; if (getClass().getClassLoader() != null) { throw new SecurityException("invalid address type"); } ObjectInputStream.GetField gf = s.readFields(); byte[] ipaddress = (byte[]) gf.get("ipaddress", new byte[0]); int scope_id = gf.get("scope_id", -1); boolean scope_id_set = gf.get("scope_id_set", false); boolean scope_ifname_set = gf.get("scope_ifname_set", false); String ifname = (String) gf.get("ifname", null); if (ifname != null && !ifname.isEmpty()) { try { scope_ifname = NetworkInterface.getByName(ifname); if (scope_ifname == null) { /* the interface does not exist on this system, so we clear * the scope information completely */ scope_id_set = false; scope_ifname_set = false; scope_id = 0; } else { scope_ifname_set = true; try { scope_id = deriveNumericScope(ipaddress, scope_ifname); } catch (UnknownHostException e) { // typically should not happen, but it may be that // the machine being used for deserialization has // the same interface name but without IPv6 configured. } } } catch (SocketException e) { } } /* if ifname was not supplied, then the numeric info is used */ ipaddress = ipaddress.clone(); // Check that our invariants are satisfied if (ipaddress.length != INADDRSZ) { throw new InvalidObjectException("invalid address length: " + ipaddress.length); } if (holder.getFamily() != IPv6) { throw new InvalidObjectException("invalid address family type"); } Inet6AddressHolder h = new Inet6AddressHolder(ipaddress, scope_id, scope_id_set, scope_ifname, scope_ifname_set); UNSAFE.putReference(this, FIELDS_OFFSET, h); } /** * default behavior is overridden in order to write the * scope_ifname field as a String, rather than a NetworkInterface * which is not serializable */ private synchronized void writeObject(ObjectOutputStream s) throws IOException { String ifname = null; if (holder6.scope_ifname != null) { ifname = holder6.scope_ifname.getName(); holder6.scope_ifname_set = true; } ObjectOutputStream.PutField pfields = s.putFields(); pfields.put("ipaddress", holder6.ipaddress); pfields.put("scope_id", holder6.scope_id); pfields.put("scope_id_set", holder6.scope_id_set); pfields.put("scope_ifname_set", holder6.scope_ifname_set); pfields.put("ifname", ifname); s.writeFields(); } /** * Utility routine to check if the InetAddress is an IP multicast * address. 11111111 at the start of the address identifies the * address as being a multicast address. * * @return a {@code boolean} indicating if the InetAddress is an IP * multicast address */ @Override public boolean isMulticastAddress() { return holder6.isMulticastAddress(); } /** * Utility routine to check if the InetAddress is a wildcard address. * * @return a {@code boolean} indicating if the InetAddress is * a wildcard address. */ @Override public boolean isAnyLocalAddress() { return holder6.isAnyLocalAddress(); } /** * 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. */ @Override public boolean isLoopbackAddress() { return holder6.isLoopbackAddress(); } /** * Utility routine to check if the InetAddress is an 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. */ @Override public boolean isLinkLocalAddress() { return holder6.isLinkLocalAddress(); } /* static version of above */ static boolean isLinkLocalAddress(byte[] ipaddress) { return ((ipaddress[0] & 0xff) == 0xfe && (ipaddress[1] & 0xc0) == 0x80); } /** * 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. */ @Override public boolean isSiteLocalAddress() { return holder6.isSiteLocalAddress(); } /* static version of above */ static boolean isSiteLocalAddress(byte[] ipaddress) { return ((ipaddress[0] & 0xff) == 0xfe && (ipaddress[1] & 0xc0) == 0xc0); } /** * 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 */ @Override public boolean isMCGlobal() { return holder6.isMCGlobal(); } /** * 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 */ @Override public boolean isMCNodeLocal() { return holder6.isMCNodeLocal(); } /** * 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 */ @Override public boolean isMCLinkLocal() { return holder6.isMCLinkLocal(); } /** * 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 */ @Override public boolean isMCSiteLocal() { return holder6.isMCSiteLocal(); } /** * 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 */ @Override public boolean isMCOrgLocal() { return holder6.isMCOrgLocal(); } /** * 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. */ @Override public byte[] getAddress() { return holder6.ipaddress.clone(); } /** * Returns the numeric scopeId, if this instance is associated with * an interface. If no scoped_id is set, the returned value is zero. * * @return the scopeId, or zero if not set. * * @since 1.5 */ public int getScopeId() { return holder6.scope_id; } /** * Returns the scoped interface, if this instance was created with * a scoped interface. * * @return the scoped interface, or null if not set. * @since 1.5 */ public NetworkInterface getScopedInterface() { return holder6.scope_ifname; } /** * Returns the IP address string in textual presentation. If the instance * was created specifying a scope identifier then the scope id is appended * to the IP address preceded by a "%" (per-cent) character. This can be * either a numeric value or a string, depending on which was used to create * the instance. * * @return the raw IP address in a string format. */ @Override public String getHostAddress() { return holder6.getHostAddress(); } /** * Returns a hashcode for this IP address. * * @return a hash code value for this IP address. */ @Override public int hashCode() { return holder6.hashCode(); } /** * 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. * * <p> 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() */ @Override public boolean equals(Object obj) { if (obj == null || !(obj instanceof Inet6Address)) return false; Inet6Address inetAddr = (Inet6Address) obj; return holder6.equals(inetAddr.holder6); } /** * Utility routine to check if the InetAddress is an * IPv4 compatible IPv6 address. * * @return a {@code boolean} indicating if the InetAddress is an IPv4 * compatible IPv6 address; or false if address is IPv4 address. */ public boolean isIPv4CompatibleAddress() { return holder6.isIPv4CompatibleAddress(); } // Utilities private static final int INT16SZ = 2; /** * Convert IPv6 binary address into presentation (printable) format. * * @param src a byte array representing the IPv6 numeric address * @return a String representing an IPv6 address in * textual representation format */ static String numericToTextFormat(byte[] src) { StringBuilder sb = new StringBuilder(39); for (int i = 0; i < (INADDRSZ / INT16SZ); i++) { sb.append(Integer.toHexString(((src[i << 1] << 8) & 0xff00) | (src[(i << 1) + 1] & 0xff))); if (i < (INADDRSZ / INT16SZ) - 1) { sb.append(":"); } } return sb.toString(); } /** * Perform class load-time initializations. */ private static native void init(); }