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	/*
	* Copyright (c) 2004, 2021, 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 sun.net.util;

	import java.io.IOException;
	import java.io.UncheckedIOException;
	import java.net.Inet6Address;
	import java.net.InetAddress;
	import java.net.InetSocketAddress;
	import java.net.NetworkInterface;
	import java.net.SocketException;
	import java.net.URL;
	import java.security.AccessController;
	import java.security.PrivilegedExceptionAction;
	import java.security.PrivilegedActionException;
	import java.util.Arrays;
	import java.util.List;
	import java.util.concurrent.ConcurrentHashMap;

	public class IPAddressUtil {
	private static final int INADDR4SZ = 4;
	private static final int INADDR16SZ = 16;
	private static final int INT16SZ = 2;

	/*
	* Converts IPv4 address in its textual presentation form
	* into its numeric binary form.
	*
	* @param src a String representing an IPv4 address in standard format
	* @return a byte array representing the IPv4 numeric address
	*/
	@SuppressWarnings("fallthrough")
	public static byte[] textToNumericFormatV4(String src)
	{
	byte[] res = new byte[INADDR4SZ];

	long tmpValue = 0;
	int currByte = 0;
	boolean newOctet = true;

	int len = src.length();
	if (len == 0 \|\| len > 15) {
	return null;
	}
	/*
	* When only one part is given, the value is stored directly in
	* the network address without any byte rearrangement.
	*
	* When a two part address is supplied, the last part is
	* interpreted as a 24-bit quantity and placed in the right
	* most three bytes of the network address. This makes the
	* two part address format convenient for specifying Class A
	* network addresses as net.host.
	*
	* When a three part address is specified, the last part is
	* interpreted as a 16-bit quantity and placed in the right
	* most two bytes of the network address. This makes the
	* three part address format convenient for specifying
	* Class B net- work addresses as 128.net.host.
	*
	* When four parts are specified, each is interpreted as a
	* byte of data and assigned, from left to right, to the
	* four bytes of an IPv4 address.
	*
	* We determine and parse the leading parts, if any, as single
	* byte values in one pass directly into the resulting byte[],
	* then the remainder is treated as a 8-to-32-bit entity and
	* translated into the remaining bytes in the array.
	*/
	for (int i = 0; i < len; i++) {
	char c = src.charAt(i);
	if (c == '.') {
	if (newOctet \|\| tmpValue < 0 \|\| tmpValue > 0xff \|\| currByte == 3) {
	return null;
	}
	res[currByte++] = (byte) (tmpValue & 0xff);
	tmpValue = 0;
	newOctet = true;
	} else {
	int digit = Character.digit(c, 10);
	if (digit < 0) {
	return null;
	}
	tmpValue *= 10;
	tmpValue += digit;
	newOctet = false;
	}
	}
	if (newOctet \|\| tmpValue < 0 \|\| tmpValue >= (1L << ((4 - currByte) * 8))) {
	return null;
	}
	switch (currByte) {
	case 0:
	res[0] = (byte) ((tmpValue >> 24) & 0xff);
	case 1:
	res[1] = (byte) ((tmpValue >> 16) & 0xff);
	case 2:
	res[2] = (byte) ((tmpValue >> 8) & 0xff);
	case 3:
	res[3] = (byte) ((tmpValue >> 0) & 0xff);
	}
	return res;
	}

	/*
	* Convert IPv6 presentation level address to network order binary form.
	* credit:
	* Converted from C code from Solaris 8 (inet_pton)
	*
	* Any component of the string following a per-cent % is ignored.
	*
	* @param src a String representing an IPv6 address in textual format
	* @return a byte array representing the IPv6 numeric address
	*/
	public static byte[] textToNumericFormatV6(String src)
	{
	// Shortest valid string is "::", hence at least 2 chars
	if (src.length() < 2) {
	return null;
	}

	int colonp;
	char ch;
	boolean saw_xdigit;
	int val;
	char[] srcb = src.toCharArray();
	byte[] dst = new byte[INADDR16SZ];

	int srcb_length = srcb.length;
	int pc = src.indexOf ('%');
	if (pc == srcb_length -1) {
	return null;
	}

	if (pc != -1) {
	srcb_length = pc;
	}

	colonp = -1;
	int i = 0, j = 0;
	/* Leading :: requires some special handling. */
	if (srcb[i] == ':')
	if (srcb[++i] != ':')
	return null;
	int curtok = i;
	saw_xdigit = false;
	val = 0;
	while (i < srcb_length) {
	ch = srcb[i++];
	int chval = Character.digit(ch, 16);
	if (chval != -1) {
	val <<= 4;
	val \|= chval;
	if (val > 0xffff)
	return null;
	saw_xdigit = true;
	continue;
	}
	if (ch == ':') {
	curtok = i;
	if (!saw_xdigit) {
	if (colonp != -1)
	return null;
	colonp = j;
	continue;
	} else if (i == srcb_length) {
	return null;
	}
	if (j + INT16SZ > INADDR16SZ)
	return null;
	dst[j++] = (byte) ((val >> 8) & 0xff);
	dst[j++] = (byte) (val & 0xff);
	saw_xdigit = false;
	val = 0;
	continue;
	}
	if (ch == '.' && ((j + INADDR4SZ) <= INADDR16SZ)) {
	String ia4 = src.substring(curtok, srcb_length);
	/* check this IPv4 address has 3 dots, i.e. A.B.C.D */
	int dot_count = 0, index=0;
	while ((index = ia4.indexOf ('.', index)) != -1) {
	dot_count ++;
	index ++;
	}
	if (dot_count != 3) {
	return null;
	}
	byte[] v4addr = textToNumericFormatV4(ia4);
	if (v4addr == null) {
	return null;
	}
	for (int k = 0; k < INADDR4SZ; k++) {
	dst[j++] = v4addr[k];
	}
	saw_xdigit = false;
	break; /* '\0' was seen by inet_pton4(). */
	}
	return null;
	}
	if (saw_xdigit) {
	if (j + INT16SZ > INADDR16SZ)
	return null;
	dst[j++] = (byte) ((val >> 8) & 0xff);
	dst[j++] = (byte) (val & 0xff);
	}

	if (colonp != -1) {
	int n = j - colonp;

	if (j == INADDR16SZ)
	return null;
	for (i = 1; i <= n; i++) {
	dst[INADDR16SZ - i] = dst[colonp + n - i];
	dst[colonp + n - i] = 0;
	}
	j = INADDR16SZ;
	}
	if (j != INADDR16SZ)
	return null;
	byte[] newdst = convertFromIPv4MappedAddress(dst);
	if (newdst != null) {
	return newdst;
	} else {
	return dst;
	}
	}

	/**
	* @param src a String representing an IPv4 address in textual format
	* @return a boolean indicating whether src is an IPv4 literal address
	*/
	public static boolean isIPv4LiteralAddress(String src) {
	return textToNumericFormatV4(src) != null;
	}

	/**
	* @param src a String representing an IPv6 address in textual format
	* @return a boolean indicating whether src is an IPv6 literal address
	*/
	public static boolean isIPv6LiteralAddress(String src) {
	return textToNumericFormatV6(src) != null;
	}

	/*
	* Convert IPv4-Mapped address to IPv4 address. Both input and
	* returned value are in network order binary form.
	*
	* @param src a String representing an IPv4-Mapped address in textual format
	* @return a byte array representing the IPv4 numeric address
	*/
	public static byte[] convertFromIPv4MappedAddress(byte[] addr) {
	if (isIPv4MappedAddress(addr)) {
	byte[] newAddr = new byte[INADDR4SZ];
	System.arraycopy(addr, 12, newAddr, 0, INADDR4SZ);
	return newAddr;
	}
	return null;
	}

	/**
	* Utility routine to check if the InetAddress is an
	* IPv4 mapped IPv6 address.
	*
	* @return a <code>boolean</code> indicating if the InetAddress is
	* an IPv4 mapped IPv6 address; or false if address is IPv4 address.
	*/
	private static boolean isIPv4MappedAddress(byte[] addr) {
	if (addr.length < INADDR16SZ) {
	return false;
	}
	if ((addr[0] == 0x00) && (addr[1] == 0x00) &&
	(addr[2] == 0x00) && (addr[3] == 0x00) &&
	(addr[4] == 0x00) && (addr[5] == 0x00) &&
	(addr[6] == 0x00) && (addr[7] == 0x00) &&
	(addr[8] == 0x00) && (addr[9] == 0x00) &&
	(addr[10] == (byte)0xff) &&
	(addr[11] == (byte)0xff)) {
	return true;
	}
	return false;
	}
	/**
	* Mapping from unscoped local Inet(6)Address to the same address
	* including the correct scope-id, determined from NetworkInterface.
	*/
	private static final ConcurrentHashMap<InetAddress,InetAddress>
	cache = new ConcurrentHashMap<>();

	/**
	* Returns a scoped version of the supplied local, link-local ipv6 address
	* if that scope-id can be determined from local NetworkInterfaces.
	* If the address already has a scope-id or if the address is not local, ipv6
	* or link local, then the original address is returned.
	*
	* @param address
	* @exception SocketException if the given ipv6 link local address is found
	* on more than one local interface
	* @return
	*/
	public static InetAddress toScopedAddress(InetAddress address)
	throws SocketException {

	if (address instanceof Inet6Address && address.isLinkLocalAddress()
	&& ((Inet6Address) address).getScopeId() == 0) {

	InetAddress cached = null;
	try {
	cached = cache.computeIfAbsent(address, k -> findScopedAddress(k));
	} catch (UncheckedIOException e) {
	throw (SocketException)e.getCause();
	}
	return cached != null ? cached : address;
	} else {
	return address;
	}
	}

	/**
	* Same as above for InetSocketAddress
	*/
	public static InetSocketAddress toScopedAddress(InetSocketAddress address)
	throws SocketException {
	InetAddress addr;
	InetAddress orig = address.getAddress();
	if ((addr = toScopedAddress(orig)) == orig) {
	return address;
	} else {
	return new InetSocketAddress(addr, address.getPort());
	}
	}

	@SuppressWarnings("removal")
	private static InetAddress findScopedAddress(InetAddress address) {
	PrivilegedExceptionAction<List<InetAddress>> pa = () -> NetworkInterface.networkInterfaces()
	.flatMap(NetworkInterface::inetAddresses)
	.filter(a -> (a instanceof Inet6Address)
	&& address.equals(a)
	&& ((Inet6Address) a).getScopeId() != 0)
	.toList();
	List<InetAddress> result;
	try {
	result = AccessController.doPrivileged(pa);
	var sz = result.size();
	if (sz == 0)
	return null;
	if (sz > 1)
	throw new UncheckedIOException(new SocketException(
	"Duplicate link local addresses: must specify scope-id"));
	return result.get(0);
	} catch (PrivilegedActionException pae) {
	return null;
	}
	}

	// See java.net.URI for more details on how to generate these
	// masks.
	//
	// square brackets
	private static final long L_IPV6_DELIMS = 0x0L; // "[]"
	private static final long H_IPV6_DELIMS = 0x28000000L; // "[]"
	// RFC 3986 gen-delims
	private static final long L_GEN_DELIMS = 0x8400800800000000L; // ":/?#[]@"
	private static final long H_GEN_DELIMS = 0x28000001L; // ":/?#[]@"
	// These gen-delims can appear in authority
	private static final long L_AUTH_DELIMS = 0x400000000000000L; // "@[]:"
	private static final long H_AUTH_DELIMS = 0x28000001L; // "@[]:"
	// colon is allowed in userinfo
	private static final long L_COLON = 0x400000000000000L; // ":"
	private static final long H_COLON = 0x0L; // ":"
	// slash should be encoded in authority
	private static final long L_SLASH = 0x800000000000L; // "/"
	private static final long H_SLASH = 0x0L; // "/"
	// backslash should always be encoded
	private static final long L_BACKSLASH = 0x0L; // "\"
	private static final long H_BACKSLASH = 0x10000000L; // "\"
	// ASCII chars 0-31 + 127 - various controls + CRLF + TAB
	private static final long L_NON_PRINTABLE = 0xffffffffL;
	private static final long H_NON_PRINTABLE = 0x8000000000000000L;
	// All of the above
	private static final long L_EXCLUDE = 0x84008008ffffffffL;
	private static final long H_EXCLUDE = 0x8000000038000001L;

	private static final char[] OTHERS = {
	8263,8264,8265,8448,8449,8453,8454,10868,
	65109,65110,65119,65131,65283,65295,65306,65311,65312
	};

	// Tell whether the given character is found by the given mask pair
	public static boolean match(char c, long lowMask, long highMask) {
	if (c < 64)
	return ((1L << c) & lowMask) != 0;
	if (c < 128)
	return ((1L << (c - 64)) & highMask) != 0;
	return false; // other non ASCII characters are not filtered
	}

	// returns -1 if the string doesn't contain any characters
	// from the mask, the index of the first such character found
	// otherwise.
	public static int scan(String s, long lowMask, long highMask) {
	int i = -1, len;
	if (s == null \|\| (len = s.length()) == 0) return -1;
	boolean match = false;
	while (++i < len && !(match = match(s.charAt(i), lowMask, highMask)));
	if (match) return i;
	return -1;
	}

	public static int scan(String s, long lowMask, long highMask, char[] others) {
	int i = -1, len;
	if (s == null \|\| (len = s.length()) == 0) return -1;
	boolean match = false;
	char c, c0 = others[0];
	while (++i < len && !(match = match((c=s.charAt(i)), lowMask, highMask))) {
	if (c >= c0 && (Arrays.binarySearch(others, c) > -1)) {
	match = true; break;
	}
	}
	if (match) return i;

	return -1;
	}

	private static String describeChar(char c) {
	if (c < 32 \|\| c == 127) {
	if (c == '\n') return "LF";
	if (c == '\r') return "CR";
	return "control char (code=" + (int)c + ")";
	}
	if (c == '\\') return "'\\'";
	return "'" + c + "'";
	}

	private static String checkUserInfo(String str) {
	// colon is permitted in user info
	int index = scan(str, L_EXCLUDE & ~L_COLON,
	H_EXCLUDE & ~H_COLON);
	if (index >= 0) {
	return "Illegal character found in user-info: "
	+ describeChar(str.charAt(index));
	}
	return null;
	}

	private static String checkHost(String str) {
	int index;
	if (str.startsWith("[") && str.endsWith("]")) {
	str = str.substring(1, str.length() - 1);
	if (isIPv6LiteralAddress(str)) {
	index = str.indexOf('%');
	if (index >= 0) {
	index = scan(str = str.substring(index),
	L_NON_PRINTABLE \| L_IPV6_DELIMS,
	H_NON_PRINTABLE \| H_IPV6_DELIMS);
	if (index >= 0) {
	return "Illegal character found in IPv6 scoped address: "
	+ describeChar(str.charAt(index));
	}
	}
	return null;
	}
	return "Unrecognized IPv6 address format";
	} else {
	index = scan(str, L_EXCLUDE, H_EXCLUDE);
	if (index >= 0) {
	return "Illegal character found in host: "
	+ describeChar(str.charAt(index));
	}
	}
	return null;
	}

	private static String checkAuth(String str) {
	int index = scan(str,
	L_EXCLUDE & ~L_AUTH_DELIMS,
	H_EXCLUDE & ~H_AUTH_DELIMS);
	if (index >= 0) {
	return "Illegal character found in authority: "
	+ describeChar(str.charAt(index));
	}
	return null;
	}

	// check authority of hierarchical URL. Appropriate for
	// HTTP-like protocol handlers
	public static String checkAuthority(URL url) {
	String s, u, h;
	if (url == null) return null;
	if ((s = checkUserInfo(u = url.getUserInfo())) != null) {
	return s;
	}
	if ((s = checkHost(h = url.getHost())) != null) {
	return s;
	}
	if (h == null && u == null) {
	return checkAuth(url.getAuthority());
	}
	return null;
	}

	// minimal syntax checks - deeper check may be performed
	// by the appropriate protocol handler
	public static String checkExternalForm(URL url) {
	String s;
	if (url == null) return null;
	int index = scan(s = url.getUserInfo(),
	L_NON_PRINTABLE \| L_SLASH,
	H_NON_PRINTABLE \| H_SLASH);
	if (index >= 0) {
	return "Illegal character found in authority: "
	+ describeChar(s.charAt(index));
	}
	if ((s = checkHostString(url.getHost())) != null) {
	return s;
	}
	return null;
	}

	public static String checkHostString(String host) {
	if (host == null) return null;
	int index = scan(host,
	L_NON_PRINTABLE \| L_SLASH,
	H_NON_PRINTABLE \| H_SLASH,
	OTHERS);
	if (index >= 0) {
	return "Illegal character found in host: "
	+ describeChar(host.charAt(index));
	}
	return null;
	}
	}

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