mirror of https://github.com/GeyserMC/Geyser.git
96 lines
3.2 KiB
Java
96 lines
3.2 KiB
Java
/*
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* Copyright (c) 2019-2021 GeyserMC. http://geysermc.org
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*
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* @author GeyserMC
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* @link https://github.com/GeyserMC/Geyser
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*/
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package org.geysermc.connector.network;
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import java.net.InetAddress;
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import java.net.UnknownHostException;
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/*
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* Taken & modified from TCPShield, licensed under MIT. See https://github.com/TCPShield/RealIP/blob/master/LICENSE
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*
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* https://github.com/TCPShield/RealIP/blob/32d422a9523cb6e25b571072851f3306bb8bbc4f/src/main/java/net/tcpshield/tcpshield/validation/cidr/CIDRMatcher.java
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*/
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public class CIDRMatcher {
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private final int maskBits;
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private final int maskBytes;
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private final boolean simpleCIDR;
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private final InetAddress cidrAddress;
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public CIDRMatcher(String ipAddress) {
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String[] split = ipAddress.split("/", 2);
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String parsedIPAddress;
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if (split.length == 2) {
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parsedIPAddress = split[0];
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this.maskBits = Integer.parseInt(split[1]);
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this.simpleCIDR = maskBits == 32;
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} else {
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parsedIPAddress = ipAddress;
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this.maskBits = -1;
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this.simpleCIDR = true;
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}
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this.maskBytes = simpleCIDR ? -1 : maskBits / 8;
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try {
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cidrAddress = InetAddress.getByName(parsedIPAddress);
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} catch (UnknownHostException e) {
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throw new RuntimeException(e);
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}
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}
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public boolean matches(InetAddress inetAddress) {
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// check if IP is IPv4 or IPv6
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if (cidrAddress.getClass() != inetAddress.getClass()) {
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return false;
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}
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// check for equality if it's a simple CIDR
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if (simpleCIDR) {
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return inetAddress.equals(cidrAddress);
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}
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byte[] inetAddressBytes = inetAddress.getAddress();
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byte[] requiredAddressBytes = cidrAddress.getAddress();
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byte finalByte = (byte) (0xFF00 >> (maskBits & 0x07));
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for (int i = 0; i < maskBytes; i++) {
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if (inetAddressBytes[i] != requiredAddressBytes[i]) {
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return false;
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}
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}
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if (finalByte != 0) {
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return (inetAddressBytes[maskBytes] & finalByte) == (requiredAddressBytes[maskBytes] & finalByte);
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}
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return true;
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}
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}
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