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 * Copyright 2014 Red Hat, Inc., and individual contributors
 * as indicated by the @author tags.
 *
 * Licensed 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.undertow.protocols.ajp;

import io.undertow.util.HeaderMap;
import io.undertow.util.HttpString;

import java.io.IOException;
import java.nio.ByteBuffer;

import static io.undertow.protocols.ajp.AjpConstants.FRAME_TYPE_END_RESPONSE;
import static io.undertow.protocols.ajp.AjpConstants.FRAME_TYPE_REQUEST_BODY_CHUNK;
import static io.undertow.protocols.ajp.AjpConstants.FRAME_TYPE_SEND_BODY_CHUNK;
import static io.undertow.protocols.ajp.AjpConstants.FRAME_TYPE_SEND_HEADERS;

Parser used for the client (i.e. load balancer) side of the AJP connection.
Author:Stuart Douglas
/** * Parser used for the client (i.e. load balancer) side of the AJP connection. * * @author Stuart Douglas */
class AjpResponseParser { public static final AjpResponseParser INSTANCE = new AjpResponseParser(); private static final int AB = ('A' << 8) + 'B'; //states public static final int BEGIN = 0; public static final int READING_MAGIC_NUMBER = 1; public static final int READING_DATA_SIZE = 2; public static final int READING_PREFIX_CODE = 3; public static final int READING_STATUS_CODE = 4; public static final int READING_REASON_PHRASE = 5; public static final int READING_NUM_HEADERS = 6; public static final int READING_HEADERS = 7; public static final int READING_PERSISTENT_BOOLEAN = 8; public static final int READING_BODY_CHUNK_LENGTH = 9; public static final int DONE = 10; //parser states int state; byte prefix; int numHeaders = 0; HttpString currentHeader; //final states int statusCode; String reasonPhrase; HeaderMap headers = new HeaderMap(); int readBodyChunkSize; public boolean isComplete() { return state == DONE; } public void parse(final ByteBuffer buf) throws IOException { if (!buf.hasRemaining()) { return; } switch (this.state) { case BEGIN: { IntegerHolder result = parse16BitInteger(buf); if (!result.readComplete) { return; } else { if (result.value != AB) { throw new IOException("Wrong magic number"); } } } case READING_DATA_SIZE: { IntegerHolder result = parse16BitInteger(buf); if (!result.readComplete) { this.state = READING_DATA_SIZE; return; } } case READING_PREFIX_CODE: { if (!buf.hasRemaining()) { this.state = READING_PREFIX_CODE; return; } else { final byte prefix = buf.get(); this.prefix = prefix; if (prefix == FRAME_TYPE_END_RESPONSE) { this.state = READING_PERSISTENT_BOOLEAN; break; } else if (prefix == FRAME_TYPE_SEND_BODY_CHUNK) { this.state = READING_BODY_CHUNK_LENGTH; break; } else if (prefix != FRAME_TYPE_SEND_HEADERS && prefix != FRAME_TYPE_REQUEST_BODY_CHUNK) { this.state = DONE; return; } } } case READING_STATUS_CODE: { //this state is overloaded for the request size //when reading state=6 (read_body_chunk requests) IntegerHolder result = parse16BitInteger(buf); if (result.readComplete) { if (this.prefix == FRAME_TYPE_SEND_HEADERS) { statusCode = result.value; } else { //read body chunk or end result //a bit hacky this.state = DONE; this.readBodyChunkSize = result.value; return; } } else { this.state = READING_STATUS_CODE; return; } } case READING_REASON_PHRASE: { StringHolder result = parseString(buf, false); if (result.readComplete) { reasonPhrase = result.value; //exchange.setRequestURI(result.value); } else { this.state = READING_REASON_PHRASE; return; } } case READING_NUM_HEADERS: { IntegerHolder result = parse16BitInteger(buf); if (!result.readComplete) { this.state = READING_NUM_HEADERS; return; } else { this.numHeaders = result.value; } } case READING_HEADERS: { int readHeaders = this.readHeaders; while (readHeaders < this.numHeaders) { if (this.currentHeader == null) { StringHolder result = parseString(buf, true); if (!result.readComplete) { this.state = READING_HEADERS; this.readHeaders = readHeaders; return; } if (result.header != null) { this.currentHeader = result.header; } else { this.currentHeader = HttpString.tryFromString(result.value); } } StringHolder result = parseString(buf, false); if (!result.readComplete) { this.state = READING_HEADERS; this.readHeaders = readHeaders; return; } headers.add(this.currentHeader, result.value); this.currentHeader = null; ++readHeaders; } break; } } if (state == READING_PERSISTENT_BOOLEAN) { if (!buf.hasRemaining()) { return; } currentIntegerPart = buf.get(); this.state = DONE; return; } else if (state == READING_BODY_CHUNK_LENGTH) { IntegerHolder result = parse16BitInteger(buf); if (result.readComplete) { this.currentIntegerPart = result.value; this.state = DONE; } return; } else { this.state = DONE; } } protected HttpString headers(int offset) { return AjpConstants.HTTP_HEADERS_ARRAY[offset]; } public HeaderMap getHeaders() { return headers; } public int getStatusCode() { return statusCode; } public String getReasonPhrase() { return reasonPhrase; } public int getReadBodyChunkSize() { return readBodyChunkSize; } public static final int STRING_LENGTH_MASK = 1 << 31;
The length of the string being read
/** * The length of the string being read */
public int stringLength = -1;
The current string being read
/** * The current string being read */
public StringBuilder currentString;
when reading the first byte of an integer this stores the first value. It is set to -1 to signify that the first byte has not been read yet.
/** * when reading the first byte of an integer this stores the first value. It is set to -1 to signify that * the first byte has not been read yet. */
public int currentIntegerPart = -1; boolean containsUrlCharacters = false; public int readHeaders = 0; public void reset() { state = 0; prefix = 0; numHeaders = 0; currentHeader = null; statusCode = 0; reasonPhrase = null; headers = new HeaderMap(); stringLength = -1; currentString = null; currentIntegerPart = -1; readHeaders = 0; } protected IntegerHolder parse16BitInteger(ByteBuffer buf) { if (!buf.hasRemaining()) { return new IntegerHolder(-1, false); } int number = this.currentIntegerPart; if (number == -1) { number = (buf.get() & 0xFF); } if (buf.hasRemaining()) { final byte b = buf.get(); int result = ((0xFF & number) << 8) + (b & 0xFF); this.currentIntegerPart = -1; return new IntegerHolder(result, true); } else { this.currentIntegerPart = number; return new IntegerHolder(-1, false); } } protected StringHolder parseString(ByteBuffer buf, boolean header) { boolean containsUrlCharacters = this.containsUrlCharacters; if (!buf.hasRemaining()) { return new StringHolder(null, false, false); } int stringLength = this.stringLength; if (stringLength == -1) { int number = buf.get() & 0xFF; if (buf.hasRemaining()) { final byte b = buf.get(); stringLength = ((0xFF & number) << 8) + (b & 0xFF); } else { this.stringLength = number | STRING_LENGTH_MASK; return new StringHolder(null, false, false); } } else if ((stringLength & STRING_LENGTH_MASK) != 0) { int number = stringLength & ~STRING_LENGTH_MASK; stringLength = ((0xFF & number) << 8) + (buf.get() & 0xFF); } if (header && (stringLength & 0xFF00) != 0) { this.stringLength = -1; return new StringHolder(headers(stringLength & 0xFF)); } if (stringLength == 0xFFFF) { //OxFFFF means null this.stringLength = -1; return new StringHolder(null, true, false); } StringBuilder builder = this.currentString; if (builder == null) { builder = new StringBuilder(); this.currentString = builder; } int length = builder.length(); while (length < stringLength) { if (!buf.hasRemaining()) { this.stringLength = stringLength; this.containsUrlCharacters = containsUrlCharacters; return new StringHolder(null, false, false); } char c = (char) buf.get(); if(c == '+' || c == '%') { containsUrlCharacters = true; } builder.append(c); ++length; } if (buf.hasRemaining()) { buf.get(); //null terminator this.currentString = null; this.stringLength = -1; this.containsUrlCharacters = false; return new StringHolder(builder.toString(), true, containsUrlCharacters); } else { this.stringLength = stringLength; this.containsUrlCharacters = containsUrlCharacters; return new StringHolder(null, false, false); } } protected static class IntegerHolder { public final int value; public final boolean readComplete; private IntegerHolder(int value, boolean readComplete) { this.value = value; this.readComplete = readComplete; } } protected static class StringHolder { public final String value; public final HttpString header; public final boolean readComplete; public final boolean containsUrlCharacters; private StringHolder(String value, boolean readComplete, boolean containsUrlCharacters) { this.value = value; this.readComplete = readComplete; this.containsUrlCharacters = containsUrlCharacters; this.header = null; } private StringHolder(HttpString value) { this.value = null; this.readComplete = true; this.header = value; this.containsUrlCharacters = false; } } }