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    • io.netty.handler.codec.haproxy.HAProxyMessageDecoder Maven / Gradle / Ivy

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    This artifact provides a single jar that contains all classes required to use remote Jakarta Enterprise Beans and Jakarta Messaging, including all dependencies. It is intended for use by those not using maven, maven users should just import the Jakarta Enterprise Beans and Jakarta Messaging BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

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    /*
 * Copyright 2014 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.haproxy;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.ByteToMessageDecoder;
import io.netty.handler.codec.ProtocolDetectionResult;
import io.netty.util.CharsetUtil;

import java.util.List;

/**
 * Decodes an HAProxy proxy protocol header
 *
 * @see Proxy Protocol Specification
 */
public class HAProxyMessageDecoder extends ByteToMessageDecoder {
    /**
     * Maximum possible length of a v1 proxy protocol header per spec
     */
    private static final int V1_MAX_LENGTH = 108;

    /**
     * Maximum possible length of a v2 proxy protocol header (fixed 16 bytes + max unsigned short)
     */
    private static final int V2_MAX_LENGTH = 16 + 65535;

    /**
     * Minimum possible length of a fully functioning v2 proxy protocol header (fixed 16 bytes + v2 address info space)
     */
    private static final int V2_MIN_LENGTH = 16 + 216;

    /**
     * Maximum possible length for v2 additional TLV data (max unsigned short - max v2 address info space)
     */
    private static final int V2_MAX_TLV = 65535 - 216;

    /**
     * Binary header prefix
     */
    private static final byte[] BINARY_PREFIX = {
            (byte) 0x0D,
            (byte) 0x0A,
            (byte) 0x0D,
            (byte) 0x0A,
            (byte) 0x00,
            (byte) 0x0D,
            (byte) 0x0A,
            (byte) 0x51,
            (byte) 0x55,
            (byte) 0x49,
            (byte) 0x54,
            (byte) 0x0A
    };

    private static final byte[] TEXT_PREFIX = {
            (byte) 'P',
            (byte) 'R',
            (byte) 'O',
            (byte) 'X',
            (byte) 'Y',
    };

    /**
     * Binary header prefix length
     */
    private static final int BINARY_PREFIX_LENGTH = BINARY_PREFIX.length;

    /**
     * {@link ProtocolDetectionResult} for {@link HAProxyProtocolVersion#V1}.
     */
    private static final ProtocolDetectionResult DETECTION_RESULT_V1 =
            ProtocolDetectionResult.detected(HAProxyProtocolVersion.V1);

    /**
     * {@link ProtocolDetectionResult} for {@link HAProxyProtocolVersion#V2}.
     */
    private static final ProtocolDetectionResult DETECTION_RESULT_V2 =
            ProtocolDetectionResult.detected(HAProxyProtocolVersion.V2);

    /**
     * Used to extract a header frame out of the {@link ByteBuf} and return it.
     */
    private HeaderExtractor headerExtractor;

    /**
     * {@code true} if we're discarding input because we're already over maxLength
     */
    private boolean discarding;

    /**
     * Number of discarded bytes
     */
    private int discardedBytes;

    /**
     * Whether or not to throw an exception as soon as we exceed maxLength.
     */
    private final boolean failFast;

    /**
     * {@code true} if we're finished decoding the proxy protocol header
     */
    private boolean finished;

    /**
     * Protocol specification version
     */
    private int version = -1;

    /**
     * The latest v2 spec (2014/05/18) allows for additional data to be sent in the proxy protocol header beyond the
     * address information block so now we need a configurable max header size
     */
    private final int v2MaxHeaderSize;

    /**
     * Creates a new decoder with no additional data (TLV) restrictions, and should throw an exception as soon as
     * we exceed maxLength.
     */
    public HAProxyMessageDecoder() {
        this(true);
    }

    /**
     * Creates a new decoder with no additional data (TLV) restrictions, whether or not to throw an exception as soon
     * as we exceed maxLength.
     *
     * @param failFast Whether or not to throw an exception as soon as we exceed maxLength
     */
    public HAProxyMessageDecoder(boolean failFast) {
        v2MaxHeaderSize = V2_MAX_LENGTH;
        this.failFast = failFast;
    }

    /**
     * Creates a new decoder with restricted additional data (TLV) size, and should throw an exception as soon as
     * we exceed maxLength.
     * 
    
     * Note: limiting TLV size only affects processing of v2, binary headers. Also, as allowed by the 1.5 spec
     * TLV data is currently ignored. For maximum performance it would be best to configure your upstream proxy host to
     * NOT send TLV data and instantiate with a max TLV size of {@code 0}.
     * 
    
     *
     * @param maxTlvSize maximum number of bytes allowed for additional data (Type-Length-Value vectors) in a v2 header
     */
    public HAProxyMessageDecoder(int maxTlvSize) {
        this(maxTlvSize, true);
    }

    /**
     * Creates a new decoder with restricted additional data (TLV) size, whether or not to throw an exception as soon
     * as we exceed maxLength.
     *
     * @param maxTlvSize maximum number of bytes allowed for additional data (Type-Length-Value vectors) in a v2 header
     * @param failFast Whether or not to throw an exception as soon as we exceed maxLength
     */
    public HAProxyMessageDecoder(int maxTlvSize, boolean failFast) {
        if (maxTlvSize < 1) {
            v2MaxHeaderSize = V2_MIN_LENGTH;
        } else if (maxTlvSize > V2_MAX_TLV) {
            v2MaxHeaderSize = V2_MAX_LENGTH;
        } else {
            int calcMax = maxTlvSize + V2_MIN_LENGTH;
            if (calcMax > V2_MAX_LENGTH) {
                v2MaxHeaderSize = V2_MAX_LENGTH;
            } else {
                v2MaxHeaderSize = calcMax;
            }
        }
        this.failFast = failFast;
    }

    /**
     * Returns the proxy protocol specification version in the buffer if the version is found.
     * Returns -1 if no version was found in the buffer.
     */
    private static int findVersion(final ByteBuf buffer) {
        final int n = buffer.readableBytes();
        // per spec, the version number is found in the 13th byte
        if (n < 13) {
            return -1;
        }

        int idx = buffer.readerIndex();
        return match(BINARY_PREFIX, buffer, idx) ? buffer.getByte(idx + BINARY_PREFIX_LENGTH) : 1;
    }

    /**
     * Returns the index in the buffer of the end of header if found.
     * Returns -1 if no end of header was found in the buffer.
     */
    private static int findEndOfHeader(final ByteBuf buffer) {
        final int n = buffer.readableBytes();

        // per spec, the 15th and 16th bytes contain the address length in bytes
        if (n < 16) {
            return -1;
        }

        int offset = buffer.readerIndex() + 14;

        // the total header length will be a fixed 16 byte sequence + the dynamic address information block
        int totalHeaderBytes = 16 + buffer.getUnsignedShort(offset);

        // ensure we actually have the full header available
        if (n >= totalHeaderBytes) {
            return totalHeaderBytes;
        } else {
            return -1;
        }
    }

    /**
     * Returns the index in the buffer of the end of line found.
     * Returns -1 if no end of line was found in the buffer.
     */
    private static int findEndOfLine(final ByteBuf buffer) {
        final int n = buffer.writerIndex();
        for (int i = buffer.readerIndex(); i < n; i++) {
            final byte b = buffer.getByte(i);
            if (b == '\r' && i < n - 1 && buffer.getByte(i + 1) == '\n') {
                return i;  // \r\n
            }
        }
        return -1;  // Not found.
    }

    @Override
    public boolean isSingleDecode() {
        // ByteToMessageDecoder uses this method to optionally break out of the decoding loop after each unit of work.
        // Since we only ever want to decode a single header we always return true to save a bit of work here.
        return true;
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        super.channelRead(ctx, msg);
        if (finished) {
            ctx.pipeline().remove(this);
        }
    }

    @Override
    protected final void decode(ChannelHandlerContext ctx, ByteBuf in, List out) throws Exception {
        // determine the specification version
        if (version == -1) {
            if ((version = findVersion(in)) == -1) {
                return;
            }
        }

        ByteBuf decoded;

        if (version == 1) {
            decoded = decodeLine(ctx, in);
        } else {
            decoded = decodeStruct(ctx, in);
        }

        if (decoded != null) {
            finished = true;
            try {
                if (version == 1) {
                    out.add(HAProxyMessage.decodeHeader(decoded.toString(CharsetUtil.US_ASCII)));
                } else {
                    out.add(HAProxyMessage.decodeHeader(decoded));
                }
            } catch (HAProxyProtocolException e) {
                fail(ctx, null, e);
            }
        }
    }

    /**
     * Create a frame out of the {@link ByteBuf} and return it.
     *
     * @param ctx     the {@link ChannelHandlerContext} which this {@link HAProxyMessageDecoder} belongs to
     * @param buffer  the {@link ByteBuf} from which to read data
     * @return frame  the {@link ByteBuf} which represent the frame or {@code null} if no frame could
     *                be created
     */
    private ByteBuf decodeStruct(ChannelHandlerContext ctx, ByteBuf buffer) throws Exception {
        if (headerExtractor == null) {
            headerExtractor = new StructHeaderExtractor(v2MaxHeaderSize);
        }
        return headerExtractor.extract(ctx, buffer);
    }

    /**
     * Create a frame out of the {@link ByteBuf} and return it.
     *
     * @param ctx     the {@link ChannelHandlerContext} which this {@link HAProxyMessageDecoder} belongs to
     * @param buffer  the {@link ByteBuf} from which to read data
     * @return frame  the {@link ByteBuf} which represent the frame or {@code null} if no frame could
     *                be created
     */
    private ByteBuf decodeLine(ChannelHandlerContext ctx, ByteBuf buffer) throws Exception {
        if (headerExtractor == null) {
            headerExtractor = new LineHeaderExtractor(V1_MAX_LENGTH);
        }
        return headerExtractor.extract(ctx, buffer);
    }

    private void failOverLimit(final ChannelHandlerContext ctx, int length) {
        failOverLimit(ctx, String.valueOf(length));
    }

    private void failOverLimit(final ChannelHandlerContext ctx, String length) {
        int maxLength = version == 1 ? V1_MAX_LENGTH : v2MaxHeaderSize;
        fail(ctx, "header length (" + length + ") exceeds the allowed maximum (" + maxLength + ')', null);
    }

    private void fail(final ChannelHandlerContext ctx, String errMsg, Exception e) {
        finished = true;
        ctx.close(); // drop connection immediately per spec
        HAProxyProtocolException ppex;
        if (errMsg != null && e != null) {
            ppex = new HAProxyProtocolException(errMsg, e);
        } else if (errMsg != null) {
            ppex = new HAProxyProtocolException(errMsg);
        } else if (e != null) {
            ppex = new HAProxyProtocolException(e);
        } else {
            ppex = new HAProxyProtocolException();
        }
        throw ppex;
    }

    /**
     * Returns the {@link ProtocolDetectionResult} for the given {@link ByteBuf}.
     */
    public static ProtocolDetectionResult detectProtocol(ByteBuf buffer) {
        if (buffer.readableBytes() < 12) {
            return ProtocolDetectionResult.needsMoreData();
        }

        int idx = buffer.readerIndex();

        if (match(BINARY_PREFIX, buffer, idx)) {
            return DETECTION_RESULT_V2;
        }
        if (match(TEXT_PREFIX, buffer, idx)) {
            return DETECTION_RESULT_V1;
        }
        return ProtocolDetectionResult.invalid();
    }

    private static boolean match(byte[] prefix, ByteBuf buffer, int idx) {
        for (int i = 0; i < prefix.length; i++) {
            final byte b = buffer.getByte(idx + i);
            if (b != prefix[i]) {
                return false;
            }
        }
        return true;
    }

    /**
     * HeaderExtractor create a header frame out of the {@link ByteBuf}.
     */
    private abstract class HeaderExtractor {
        /** Header max size */
        private final int maxHeaderSize;

        protected HeaderExtractor(int maxHeaderSize) {
            this.maxHeaderSize = maxHeaderSize;
        }

        /**
         * Create a frame out of the {@link ByteBuf} and return it.
         *
         * @param ctx     the {@link ChannelHandlerContext} which this {@link HAProxyMessageDecoder} belongs to
         * @param buffer  the {@link ByteBuf} from which to read data
         * @return frame  the {@link ByteBuf} which represent the frame or {@code null} if no frame could
         *                be created
         * @throws Exception if exceed maxLength
         */
        public ByteBuf extract(ChannelHandlerContext ctx, ByteBuf buffer) throws Exception {
            final int eoh = findEndOfHeader(buffer);
            if (!discarding) {
                if (eoh >= 0) {
                    final int length = eoh - buffer.readerIndex();
                    if (length > maxHeaderSize) {
                        buffer.readerIndex(eoh + delimiterLength(buffer, eoh));
                        failOverLimit(ctx, length);
                        return null;
                    }
                    ByteBuf frame = buffer.readSlice(length);
                    buffer.skipBytes(delimiterLength(buffer, eoh));
                    return frame;
                } else {
                    final int length = buffer.readableBytes();
                    if (length > maxHeaderSize) {
                        discardedBytes = length;
                        buffer.skipBytes(length);
                        discarding = true;
                        if (failFast) {
                            failOverLimit(ctx, "over " + discardedBytes);
                        }
                    }
                    return null;
                }
            } else {
                if (eoh >= 0) {
                    final int length = discardedBytes + eoh - buffer.readerIndex();
                    buffer.readerIndex(eoh + delimiterLength(buffer, eoh));
                    discardedBytes = 0;
                    discarding = false;
                    if (!failFast) {
                        failOverLimit(ctx, "over " + length);
                    }
                } else {
                    discardedBytes += buffer.readableBytes();
                    buffer.skipBytes(buffer.readableBytes());
                }
                return null;
            }
        }

        /**
         * Find the end of the header from the given {@link ByteBuf}，the end may be a CRLF, or the length given by the
         * header.
         *
         * @param buffer the buffer to be searched
         * @return {@code -1} if can not find the end, otherwise return the buffer index of end
         */
        protected abstract int findEndOfHeader(ByteBuf buffer);

        /**
         * Get the length of the header delimiter.
         *
         * @param buffer the buffer where delimiter is located
         * @param eoh index of delimiter
         * @return length of the delimiter
         */
        protected abstract int delimiterLength(ByteBuf buffer, int eoh);
    }

    private final class LineHeaderExtractor extends HeaderExtractor {

        LineHeaderExtractor(int maxHeaderSize) {
            super(maxHeaderSize);
        }

        @Override
        protected int findEndOfHeader(ByteBuf buffer) {
            return findEndOfLine(buffer);
        }

        @Override
        protected int delimiterLength(ByteBuf buffer, int eoh) {
            return buffer.getByte(eoh) == '\r' ? 2 : 1;
        }
    }

    private final class StructHeaderExtractor extends HeaderExtractor {

        StructHeaderExtractor(int maxHeaderSize) {
            super(maxHeaderSize);
        }

        @Override
        protected int findEndOfHeader(ByteBuf buffer) {
            return HAProxyMessageDecoder.findEndOfHeader(buffer);
        }

        @Override
        protected int delimiterLength(ByteBuf buffer, int eoh) {
            return 0;
        }
    }
}
    
    
    
    

    




    
    
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