1 /*
2 * Copyright 2015 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License,
5 * version 2.0 (the "License"); you may not use this file except in compliance
6 * with the License. You may obtain a copy of the License at:
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 package io.netty.handler.codec.rtsp;
17
18 import java.util.regex.Pattern;
19
20 import io.netty.buffer.Unpooled;
21 import io.netty.handler.codec.http.DefaultFullHttpRequest;
22 import io.netty.handler.codec.http.DefaultFullHttpResponse;
23 import io.netty.handler.codec.http.DefaultHttpRequest;
24 import io.netty.handler.codec.http.DefaultHttpResponse;
25 import io.netty.handler.codec.http.HttpMessage;
26 import io.netty.handler.codec.http.HttpObjectDecoder;
27 import io.netty.handler.codec.http.HttpResponseStatus;
28
29 /**
30 * Decodes {@link ByteBuf}s into RTSP messages represented in
31 * {@link HttpMessage}s.
32 * <p>
33 * <h3>Parameters that prevents excessive memory consumption</h3>
34 * <table border="1">
35 * <tr>
36 * <th>Name</th><th>Meaning</th>
37 * </tr>
38 * <tr>
39 * <td>{@code maxInitialLineLength}</td>
40 * <td>The maximum length of the initial line
41 * (e.g. {@code "SETUP / RTSP/1.0"} or {@code "RTSP/1.0 200 OK"})
42 * If the length of the initial line exceeds this value, a
43 * {@link TooLongFrameException} will be raised.</td>
44 * </tr>
45 * <tr>
46 * <td>{@code maxHeaderSize}</td>
47 * <td>The maximum length of all headers. If the sum of the length of each
48 * header exceeds this value, a {@link TooLongFrameException} will be
49 * raised.</td>
50 * </tr>
51 * <tr>
52 * <td>{@code maxContentLength}</td>
53 * <td>The maximum length of the content. If the content length exceeds this
54 * value, a {@link TooLongFrameException} will be raised.</td>
55 * </tr>
56 * </table>
57 */
58 public class RtspDecoder extends HttpObjectDecoder {
59 /**
60 * Status code for unknown responses.
61 */
62 private static final HttpResponseStatus UNKNOWN_STATUS =
63 new HttpResponseStatus(999, "Unknown");
64 /**
65 * True if the message to decode is a request.
66 * False if the message to decode is a response.
67 */
68 private boolean isDecodingRequest;
69
70 /**
71 * Regex used on first line in message to detect if it is a response.
72 */
73 private static final Pattern versionPattern = Pattern.compile("RTSP/\\d\\.\\d");
74
75 /**
76 * Constant for default max initial line length.
77 */
78 public static final int DEFAULT_MAX_INITIAL_LINE_LENGTH = 4096;
79
80 /**
81 * Constant for default max header size.
82 */
83 public static final int DEFAULT_MAX_HEADER_SIZE = 8192;
84
85 /**
86 * Constant for default max content length.
87 */
88 public static final int DEFAULT_MAX_CONTENT_LENGTH = 8192;
89
90 /**
91 * Creates a new instance with the default
92 * {@code maxInitialLineLength (4096)}, {@code maxHeaderSize (8192)}, and
93 * {@code maxContentLength (8192)}.
94 */
95 public RtspDecoder() {
96 this(DEFAULT_MAX_INITIAL_LINE_LENGTH,
97 DEFAULT_MAX_HEADER_SIZE,
98 DEFAULT_MAX_CONTENT_LENGTH);
99 }
100
101 /**
102 * Creates a new instance with the specified parameters.
103 * @param maxInitialLineLength The max allowed length of initial line
104 * @param maxHeaderSize The max allowed size of header
105 * @param maxContentLength The max allowed content length
106 */
107 public RtspDecoder(final int maxInitialLineLength,
108 final int maxHeaderSize,
109 final int maxContentLength) {
110 super(maxInitialLineLength, maxHeaderSize, maxContentLength * 2, false);
111 }
112
113 /**
114 * Creates a new instance with the specified parameters.
115 * @param maxInitialLineLength The max allowed length of initial line
116 * @param maxHeaderSize The max allowed size of header
117 * @param maxContentLength The max allowed content length
118 * @param validateHeaders Set to true if headers should be validated
119 */
120 public RtspDecoder(final int maxInitialLineLength,
121 final int maxHeaderSize,
122 final int maxContentLength,
123 final boolean validateHeaders) {
124 super(maxInitialLineLength,
125 maxHeaderSize,
126 maxContentLength * 2,
127 false,
128 validateHeaders);
129 }
130
131 @Override
132 protected HttpMessage createMessage(final String[] initialLine)
133 throws Exception {
134 // If the first element of the initial line is a version string then
135 // this is a response
136 if (versionPattern.matcher(initialLine[0]).matches()) {
137 isDecodingRequest = false;
138 return new DefaultHttpResponse(RtspVersions.valueOf(initialLine[0]),
139 new HttpResponseStatus(Integer.parseInt(initialLine[1]),
140 initialLine[2]),
141 validateHeaders);
142 } else {
143 isDecodingRequest = true;
144 return new DefaultHttpRequest(RtspVersions.valueOf(initialLine[2]),
145 RtspMethods.valueOf(initialLine[0]),
146 initialLine[1],
147 validateHeaders);
148 }
149 }
150
151 @Override
152 protected boolean isContentAlwaysEmpty(final HttpMessage msg) {
153 // Unlike HTTP, RTSP always assumes zero-length body if Content-Length
154 // header is absent.
155 return super.isContentAlwaysEmpty(msg) || !msg.headers().contains(RtspHeaders.Names.CONTENT_LENGTH);
156 }
157
158 @Override
159 protected HttpMessage createInvalidMessage() {
160 if (isDecodingRequest) {
161 return new DefaultFullHttpRequest(RtspVersions.RTSP_1_0,
162 RtspMethods.OPTIONS, "/bad-request", Unpooled.EMPTY_BUFFER, validateHeaders);
163 } else {
164 return new DefaultFullHttpResponse(RtspVersions.RTSP_1_0,
165 UNKNOWN_STATUS, Unpooled.EMPTY_BUFFER,
166 validateHeaders);
167 }
168 }
169
170 @Override
171 protected boolean isDecodingRequest() {
172 return isDecodingRequest;
173 }
174 }