View Javadoc
1   /*
2    * Copyright 2014 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    *   https://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.spdy;
17  
18  import io.netty.buffer.ByteBuf;
19  import io.netty.buffer.ByteBufAllocator;
20  import io.netty.util.internal.ObjectUtil;
21  
22  import java.nio.ByteOrder;
23  import java.util.Set;
24  
25  import static io.netty.handler.codec.spdy.SpdyCodecUtil.*;
26  
27  /**
28   * Encodes a SPDY Frame into a {@link ByteBuf}.
29   */
30  public class SpdyFrameEncoder {
31  
32      private final int version;
33  
34      /**
35       * Creates a new instance with the specified {@code spdyVersion}.
36       */
37      public SpdyFrameEncoder(SpdyVersion spdyVersion) {
38          version = ObjectUtil.checkNotNull(spdyVersion, "spdyVersion").version();
39      }
40  
41      protected void writeControlFrameHeader(ByteBuf buffer, int type, byte flags, int length) {
42          buffer.writeShort(version | 0x8000);
43          buffer.writeShort(type);
44          buffer.writeByte(flags);
45          buffer.writeMedium(length);
46      }
47  
48      public ByteBuf encodeDataFrame(ByteBufAllocator allocator, int streamId, boolean last, ByteBuf data) {
49          byte flags = last ? SPDY_DATA_FLAG_FIN : 0;
50          int length = data.readableBytes();
51          ByteBuf frame = allocator.ioBuffer(SPDY_HEADER_SIZE + length).order(ByteOrder.BIG_ENDIAN);
52          frame.writeInt(streamId & 0x7FFFFFFF);
53          frame.writeByte(flags);
54          frame.writeMedium(length);
55          frame.writeBytes(data, data.readerIndex(), length);
56          return frame;
57      }
58  
59      public ByteBuf encodeSynStreamFrame(ByteBufAllocator allocator,  int streamId, int associatedToStreamId,
60              byte priority, boolean last, boolean unidirectional, ByteBuf headerBlock) {
61          int headerBlockLength = headerBlock.readableBytes();
62          byte flags = last ? SPDY_FLAG_FIN : 0;
63          if (unidirectional) {
64              flags |= SPDY_FLAG_UNIDIRECTIONAL;
65          }
66          int length = 10 + headerBlockLength;
67          ByteBuf frame = allocator.ioBuffer(SPDY_HEADER_SIZE + length).order(ByteOrder.BIG_ENDIAN);
68          writeControlFrameHeader(frame, SPDY_SYN_STREAM_FRAME, flags, length);
69          frame.writeInt(streamId);
70          frame.writeInt(associatedToStreamId);
71          frame.writeShort((priority & 0xFF) << 13);
72          frame.writeBytes(headerBlock, headerBlock.readerIndex(), headerBlockLength);
73          return frame;
74      }
75  
76      public ByteBuf encodeSynReplyFrame(ByteBufAllocator allocator, int streamId, boolean last, ByteBuf headerBlock) {
77          int headerBlockLength = headerBlock.readableBytes();
78          byte flags = last ? SPDY_FLAG_FIN : 0;
79          int length = 4 + headerBlockLength;
80          ByteBuf frame = allocator.ioBuffer(SPDY_HEADER_SIZE + length).order(ByteOrder.BIG_ENDIAN);
81          writeControlFrameHeader(frame, SPDY_SYN_REPLY_FRAME, flags, length);
82          frame.writeInt(streamId);
83          frame.writeBytes(headerBlock, headerBlock.readerIndex(), headerBlockLength);
84          return frame;
85      }
86  
87      public ByteBuf encodeRstStreamFrame(ByteBufAllocator allocator, int streamId, int statusCode) {
88          byte flags = 0;
89          int length = 8;
90          ByteBuf frame = allocator.ioBuffer(SPDY_HEADER_SIZE + length).order(ByteOrder.BIG_ENDIAN);
91          writeControlFrameHeader(frame, SPDY_RST_STREAM_FRAME, flags, length);
92          frame.writeInt(streamId);
93          frame.writeInt(statusCode);
94          return frame;
95      }
96  
97      public ByteBuf encodeSettingsFrame(ByteBufAllocator allocator, SpdySettingsFrame spdySettingsFrame) {
98          Set<Integer> ids = spdySettingsFrame.ids();
99          int numSettings = ids.size();
100 
101         byte flags = spdySettingsFrame.clearPreviouslyPersistedSettings() ?
102                 SPDY_SETTINGS_CLEAR : 0;
103         int length = 4 + 8 * numSettings;
104         ByteBuf frame = allocator.ioBuffer(SPDY_HEADER_SIZE + length).order(ByteOrder.BIG_ENDIAN);
105         writeControlFrameHeader(frame, SPDY_SETTINGS_FRAME, flags, length);
106         frame.writeInt(numSettings);
107         for (Integer id : ids) {
108             flags = 0;
109             if (spdySettingsFrame.isPersistValue(id)) {
110                 flags |= SPDY_SETTINGS_PERSIST_VALUE;
111             }
112             if (spdySettingsFrame.isPersisted(id)) {
113                 flags |= SPDY_SETTINGS_PERSISTED;
114             }
115             frame.writeByte(flags);
116             frame.writeMedium(id);
117             frame.writeInt(spdySettingsFrame.getValue(id));
118         }
119         return frame;
120     }
121 
122     public ByteBuf encodePingFrame(ByteBufAllocator allocator, int id) {
123         byte flags = 0;
124         int length = 4;
125         ByteBuf frame = allocator.ioBuffer(SPDY_HEADER_SIZE + length).order(ByteOrder.BIG_ENDIAN);
126         writeControlFrameHeader(frame, SPDY_PING_FRAME, flags, length);
127         frame.writeInt(id);
128         return frame;
129     }
130 
131     public ByteBuf encodeGoAwayFrame(ByteBufAllocator allocator, int lastGoodStreamId, int statusCode) {
132         byte flags = 0;
133         int length = 8;
134         ByteBuf frame = allocator.ioBuffer(SPDY_HEADER_SIZE + length).order(ByteOrder.BIG_ENDIAN);
135         writeControlFrameHeader(frame, SPDY_GOAWAY_FRAME, flags, length);
136         frame.writeInt(lastGoodStreamId);
137         frame.writeInt(statusCode);
138         return frame;
139     }
140 
141     public ByteBuf encodeHeadersFrame(ByteBufAllocator allocator, int streamId, boolean last, ByteBuf headerBlock) {
142         int headerBlockLength = headerBlock.readableBytes();
143         byte flags = last ? SPDY_FLAG_FIN : 0;
144         int length = 4 + headerBlockLength;
145         ByteBuf frame = allocator.ioBuffer(SPDY_HEADER_SIZE + length).order(ByteOrder.BIG_ENDIAN);
146         writeControlFrameHeader(frame, SPDY_HEADERS_FRAME, flags, length);
147         frame.writeInt(streamId);
148         frame.writeBytes(headerBlock, headerBlock.readerIndex(), headerBlockLength);
149         return frame;
150     }
151 
152     public ByteBuf encodeWindowUpdateFrame(ByteBufAllocator allocator, int streamId, int deltaWindowSize) {
153         byte flags = 0;
154         int length = 8;
155         ByteBuf frame = allocator.ioBuffer(SPDY_HEADER_SIZE + length).order(ByteOrder.BIG_ENDIAN);
156         writeControlFrameHeader(frame, SPDY_WINDOW_UPDATE_FRAME, flags, length);
157         frame.writeInt(streamId);
158         frame.writeInt(deltaWindowSize);
159         return frame;
160     }
161 
162     public ByteBuf encodeUnknownFrame(ByteBufAllocator allocator, int frameType, byte flags, ByteBuf data) {
163         int length = data.readableBytes();
164         ByteBuf frame = allocator.ioBuffer(SPDY_HEADER_SIZE + length).order(ByteOrder.BIG_ENDIAN);
165         writeControlFrameHeader(frame, frameType, flags, length);
166         if (length > 0) {
167             frame.writeBytes(data, data.readerIndex(), length);
168         }
169         return frame;
170     }
171 }