io.netty.handler.codec.socks.SocksCommonUtils Maven / Gradle / Ivy
/*
* Copyright 2012 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package io.netty.handler.codec.socks;
import io.netty.util.internal.StringUtil;
final class SocksCommonUtils {
public static final SocksRequest UNKNOWN_SOCKS_REQUEST = new UnknownSocksRequest();
public static final SocksResponse UNKNOWN_SOCKS_RESPONSE = new UnknownSocksResponse();
private static final int SECOND_ADDRESS_OCTET_SHIFT = 16;
private static final int FIRST_ADDRESS_OCTET_SHIFT = 24;
private static final int THIRD_ADDRESS_OCTET_SHIFT = 8;
private static final int XOR_DEFAULT_VALUE = 0xff;
/**
* A constructor to stop this class being constructed.
*/
private SocksCommonUtils() {
// NOOP
}
public static String intToIp(int i) {
return String.valueOf(i >> FIRST_ADDRESS_OCTET_SHIFT & XOR_DEFAULT_VALUE) + '.' +
(i >> SECOND_ADDRESS_OCTET_SHIFT & XOR_DEFAULT_VALUE) + '.' +
(i >> THIRD_ADDRESS_OCTET_SHIFT & XOR_DEFAULT_VALUE) + '.' +
(i & XOR_DEFAULT_VALUE);
}
private static final char[] ipv6conseqZeroFiller = {':', ':'};
private static final char ipv6hextetSeparator = ':';
/**
* Convert numeric IPv6 to compressed format, where
* the longest sequence of 0's (with 2 or more 0's) is replaced with "::"
*/
public static String ipv6toCompressedForm(byte[] src) {
assert src.length == 16;
//Find the longest sequence of 0's
//start of compressed region (hextet index)
int cmprHextet = -1;
//length of compressed region
int cmprSize = 0;
for (int hextet = 0; hextet < 8;) {
int curByte = hextet * 2;
int size = 0;
while (curByte < src.length && src[curByte] == 0
&& src[curByte + 1] == 0) {
curByte += 2;
size++;
}
if (size > cmprSize) {
cmprHextet = hextet;
cmprSize = size;
}
hextet = curByte / 2 + 1;
}
if (cmprHextet == -1 || cmprSize < 2) {
//No compression can be applied
return ipv6toStr(src);
}
StringBuilder sb = new StringBuilder(39);
ipv6toStr(sb, src, 0, cmprHextet);
sb.append(ipv6conseqZeroFiller);
ipv6toStr(sb, src, cmprHextet + cmprSize, 8);
return sb.toString();
}
/**
* Converts numeric IPv6 to standard (non-compressed) format.
*/
public static String ipv6toStr(byte[] src) {
assert src.length == 16;
StringBuilder sb = new StringBuilder(39);
ipv6toStr(sb, src, 0, 8);
return sb.toString();
}
private static void ipv6toStr(StringBuilder sb, byte[] src, int fromHextet, int toHextet) {
int i;
toHextet --;
for (i = fromHextet; i < toHextet; i++) {
appendHextet(sb, src, i);
sb.append(ipv6hextetSeparator);
}
appendHextet(sb, src, i);
}
private static void appendHextet(StringBuilder sb, byte[] src, int i) {
StringUtil.toHexString(sb, src, i << 1, 2);
}
}