1 // Copyright 2013 The Chromium Authors
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "net/websockets/websocket_inflater.h"
6
7 #include <string.h>
8
9 #include <algorithm>
10 #include <vector>
11
12 #include "base/check.h"
13 #include "base/check_op.h"
14 #include "net/base/io_buffer.h"
15 #include "third_party/zlib/zlib.h"
16
17 namespace net {
18
19 namespace {
20
21 class ShrinkableIOBufferWithSize : public IOBufferWithSize {
22 public:
ShrinkableIOBufferWithSize(size_t size)23 explicit ShrinkableIOBufferWithSize(size_t size) : IOBufferWithSize(size) {}
24
Shrink(int new_size)25 void Shrink(int new_size) {
26 CHECK_GE(new_size, 0);
27 CHECK_LE(new_size, size_);
28 size_ = new_size;
29 }
30
31 private:
32 ~ShrinkableIOBufferWithSize() override = default;
33 };
34
35 } // namespace
36
WebSocketInflater()37 WebSocketInflater::WebSocketInflater()
38 : input_queue_(kDefaultInputIOBufferCapacity),
39 output_buffer_(kDefaultBufferCapacity) {}
40
WebSocketInflater(size_t input_queue_capacity,size_t output_buffer_capacity)41 WebSocketInflater::WebSocketInflater(size_t input_queue_capacity,
42 size_t output_buffer_capacity)
43 : input_queue_(input_queue_capacity),
44 output_buffer_(output_buffer_capacity) {
45 DCHECK_GT(input_queue_capacity, 0u);
46 DCHECK_GT(output_buffer_capacity, 0u);
47 }
48
Initialize(int window_bits)49 bool WebSocketInflater::Initialize(int window_bits) {
50 DCHECK_LE(8, window_bits);
51 DCHECK_GE(15, window_bits);
52 stream_ = std::make_unique<z_stream>();
53 memset(stream_.get(), 0, sizeof(*stream_));
54 int result = inflateInit2(stream_.get(), -window_bits);
55 if (result != Z_OK) {
56 inflateEnd(stream_.get());
57 stream_.reset();
58 return false;
59 }
60 return true;
61 }
62
~WebSocketInflater()63 WebSocketInflater::~WebSocketInflater() {
64 if (stream_) {
65 inflateEnd(stream_.get());
66 stream_.reset();
67 }
68 }
69
AddBytes(const char * data,size_t size)70 bool WebSocketInflater::AddBytes(const char* data, size_t size) {
71 if (!size)
72 return true;
73
74 if (!input_queue_.IsEmpty()) {
75 // choked
76 input_queue_.Push(data, size);
77 return true;
78 }
79
80 int result = InflateWithFlush(data, size);
81 if (stream_->avail_in > 0)
82 input_queue_.Push(&data[size - stream_->avail_in], stream_->avail_in);
83
84 return result == Z_OK || result == Z_BUF_ERROR;
85 }
86
Finish()87 bool WebSocketInflater::Finish() {
88 return AddBytes("\x00\x00\xff\xff", 4);
89 }
90
GetOutput(size_t size)91 scoped_refptr<IOBufferWithSize> WebSocketInflater::GetOutput(size_t size) {
92 auto buffer = base::MakeRefCounted<ShrinkableIOBufferWithSize>(size);
93 size_t num_bytes_copied = 0;
94
95 while (num_bytes_copied < size && output_buffer_.Size() > 0) {
96 size_t num_bytes_to_copy =
97 std::min(output_buffer_.Size(), size - num_bytes_copied);
98 output_buffer_.Read(&buffer->data()[num_bytes_copied], num_bytes_to_copy);
99 num_bytes_copied += num_bytes_to_copy;
100 int result = InflateChokedInput();
101 if (result != Z_OK && result != Z_BUF_ERROR)
102 return nullptr;
103 }
104 buffer->Shrink(num_bytes_copied);
105 return buffer;
106 }
107
InflateWithFlush(const char * next_in,size_t avail_in)108 int WebSocketInflater::InflateWithFlush(const char* next_in, size_t avail_in) {
109 int result = Inflate(next_in, avail_in, Z_NO_FLUSH);
110 if (result != Z_OK && result != Z_BUF_ERROR)
111 return result;
112
113 if (CurrentOutputSize() > 0)
114 return result;
115 // CurrentOutputSize() == 0 means there is no data to be output,
116 // so we should make sure it by using Z_SYNC_FLUSH.
117 return Inflate(reinterpret_cast<const char*>(stream_->next_in),
118 stream_->avail_in,
119 Z_SYNC_FLUSH);
120 }
121
Inflate(const char * next_in,size_t avail_in,int flush)122 int WebSocketInflater::Inflate(const char* next_in,
123 size_t avail_in,
124 int flush) {
125 stream_->next_in = reinterpret_cast<Bytef*>(const_cast<char*>(next_in));
126 stream_->avail_in = avail_in;
127
128 int result = Z_BUF_ERROR;
129 do {
130 std::pair<char*, size_t> tail = output_buffer_.GetTail();
131 if (!tail.second)
132 break;
133
134 stream_->next_out = reinterpret_cast<Bytef*>(tail.first);
135 stream_->avail_out = tail.second;
136 result = inflate(stream_.get(), flush);
137 output_buffer_.AdvanceTail(tail.second - stream_->avail_out);
138 if (result == Z_STREAM_END) {
139 // Received a block with BFINAL set to 1. Reset the decompression state.
140 result = inflateReset(stream_.get());
141 } else if (tail.second == stream_->avail_out) {
142 break;
143 }
144 } while (result == Z_OK || result == Z_BUF_ERROR);
145 return result;
146 }
147
InflateChokedInput()148 int WebSocketInflater::InflateChokedInput() {
149 if (input_queue_.IsEmpty())
150 return InflateWithFlush(nullptr, 0);
151
152 int result = Z_BUF_ERROR;
153 while (!input_queue_.IsEmpty()) {
154 std::pair<char*, size_t> top = input_queue_.Top();
155
156 result = InflateWithFlush(top.first, top.second);
157 input_queue_.Consume(top.second - stream_->avail_in);
158
159 if (result != Z_OK && result != Z_BUF_ERROR)
160 return result;
161
162 if (stream_->avail_in > 0) {
163 // There are some data which are not consumed.
164 break;
165 }
166 }
167 return result;
168 }
169
OutputBuffer(size_t capacity)170 WebSocketInflater::OutputBuffer::OutputBuffer(size_t capacity)
171 : capacity_(capacity),
172 buffer_(capacity_ + 1) // 1 for sentinel
173 {}
174
175 WebSocketInflater::OutputBuffer::~OutputBuffer() = default;
176
Size() const177 size_t WebSocketInflater::OutputBuffer::Size() const {
178 return (tail_ + buffer_.size() - head_) % buffer_.size();
179 }
180
GetTail()181 std::pair<char*, size_t> WebSocketInflater::OutputBuffer::GetTail() {
182 DCHECK_LT(tail_, buffer_.size());
183 return std::pair(&buffer_[tail_],
184 std::min(capacity_ - Size(), buffer_.size() - tail_));
185 }
186
Read(char * dest,size_t size)187 void WebSocketInflater::OutputBuffer::Read(char* dest, size_t size) {
188 DCHECK_LE(size, Size());
189
190 size_t num_bytes_copied = 0;
191 if (tail_ < head_) {
192 size_t num_bytes_to_copy = std::min(size, buffer_.size() - head_);
193 DCHECK_LT(head_, buffer_.size());
194 memcpy(&dest[num_bytes_copied], &buffer_[head_], num_bytes_to_copy);
195 AdvanceHead(num_bytes_to_copy);
196 num_bytes_copied += num_bytes_to_copy;
197 }
198
199 if (num_bytes_copied == size)
200 return;
201 DCHECK_LE(head_, tail_);
202 size_t num_bytes_to_copy = size - num_bytes_copied;
203 DCHECK_LE(num_bytes_to_copy, tail_ - head_);
204 DCHECK_LT(head_, buffer_.size());
205 memcpy(&dest[num_bytes_copied], &buffer_[head_], num_bytes_to_copy);
206 AdvanceHead(num_bytes_to_copy);
207 num_bytes_copied += num_bytes_to_copy;
208 DCHECK_EQ(size, num_bytes_copied);
209 return;
210 }
211
AdvanceHead(size_t advance)212 void WebSocketInflater::OutputBuffer::AdvanceHead(size_t advance) {
213 DCHECK_LE(advance, Size());
214 head_ = (head_ + advance) % buffer_.size();
215 }
216
AdvanceTail(size_t advance)217 void WebSocketInflater::OutputBuffer::AdvanceTail(size_t advance) {
218 DCHECK_LE(advance + Size(), capacity_);
219 tail_ = (tail_ + advance) % buffer_.size();
220 }
221
InputQueue(size_t capacity)222 WebSocketInflater::InputQueue::InputQueue(size_t capacity)
223 : capacity_(capacity) {}
224
225 WebSocketInflater::InputQueue::~InputQueue() = default;
226
Top()227 std::pair<char*, size_t> WebSocketInflater::InputQueue::Top() {
228 DCHECK(!IsEmpty());
229 if (buffers_.size() == 1) {
230 return std::pair(&buffers_.front()->data()[head_of_first_buffer_],
231 tail_of_last_buffer_ - head_of_first_buffer_);
232 }
233 return std::pair(&buffers_.front()->data()[head_of_first_buffer_],
234 capacity_ - head_of_first_buffer_);
235 }
236
Push(const char * data,size_t size)237 void WebSocketInflater::InputQueue::Push(const char* data, size_t size) {
238 if (!size)
239 return;
240
241 size_t num_copied_bytes = 0;
242 if (!IsEmpty())
243 num_copied_bytes += PushToLastBuffer(data, size);
244
245 while (num_copied_bytes < size) {
246 DCHECK(IsEmpty() || tail_of_last_buffer_ == capacity_);
247
248 buffers_.push_back(base::MakeRefCounted<IOBufferWithSize>(capacity_));
249 tail_of_last_buffer_ = 0;
250 num_copied_bytes +=
251 PushToLastBuffer(&data[num_copied_bytes], size - num_copied_bytes);
252 }
253 }
254
Consume(size_t size)255 void WebSocketInflater::InputQueue::Consume(size_t size) {
256 DCHECK(!IsEmpty());
257 DCHECK_LE(size + head_of_first_buffer_, capacity_);
258
259 head_of_first_buffer_ += size;
260 if (head_of_first_buffer_ == capacity_) {
261 buffers_.pop_front();
262 head_of_first_buffer_ = 0;
263 }
264 if (buffers_.size() == 1 && head_of_first_buffer_ == tail_of_last_buffer_) {
265 buffers_.pop_front();
266 head_of_first_buffer_ = 0;
267 tail_of_last_buffer_ = 0;
268 }
269 }
270
PushToLastBuffer(const char * data,size_t size)271 size_t WebSocketInflater::InputQueue::PushToLastBuffer(const char* data,
272 size_t size) {
273 DCHECK(!IsEmpty());
274 size_t num_bytes_to_copy = std::min(size, capacity_ - tail_of_last_buffer_);
275 if (!num_bytes_to_copy)
276 return 0;
277 IOBufferWithSize* buffer = buffers_.back().get();
278 memcpy(&buffer->data()[tail_of_last_buffer_], data, num_bytes_to_copy);
279 tail_of_last_buffer_ += num_bytes_to_copy;
280 return num_bytes_to_copy;
281 }
282
283 } // namespace net
284