blob: 2bbb8e4912fef9900dca5ca01874d688b7c2db6b [file] [log] [blame]
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "net/websockets/websocket_frame_parser.h"
#include <algorithm>
#include <limits>
#include <utility>
#include <vector>
#include "base/big_endian.h"
#include "base/logging.h"
#include "base/memory/scoped_refptr.h"
#include "net/base/io_buffer.h"
#include "net/websockets/websocket_frame.h"
#include "starboard/memory.h"
namespace {
const uint8_t kFinalBit = 0x80;
const uint8_t kReserved1Bit = 0x40;
const uint8_t kReserved2Bit = 0x20;
const uint8_t kReserved3Bit = 0x10;
const uint8_t kOpCodeMask = 0xF;
const uint8_t kMaskBit = 0x80;
const uint8_t kPayloadLengthMask = 0x7F;
const uint64_t kMaxPayloadLengthWithoutExtendedLengthField = 125;
const uint64_t kPayloadLengthWithTwoByteExtendedLengthField = 126;
const uint64_t kPayloadLengthWithEightByteExtendedLengthField = 127;
} // namespace.
namespace net {
WebSocketFrameParser::WebSocketFrameParser()
: current_read_pos_(0),
frame_offset_(0),
websocket_error_(kWebSocketNormalClosure) {
std::fill(masking_key_.key,
masking_key_.key + WebSocketFrameHeader::kMaskingKeyLength,
'\0');
}
WebSocketFrameParser::~WebSocketFrameParser() = default;
bool WebSocketFrameParser::Decode(
const char* data,
size_t length,
std::vector<std::unique_ptr<WebSocketFrameChunk>>* frame_chunks) {
if (websocket_error_ != kWebSocketNormalClosure)
return false;
if (!length)
return true;
// TODO(yutak): Remove copy.
buffer_.insert(buffer_.end(), data, data + length);
while (current_read_pos_ < buffer_.size()) {
bool first_chunk = false;
if (!current_frame_header_.get()) {
DecodeFrameHeader();
if (websocket_error_ != kWebSocketNormalClosure)
return false;
// If frame header is incomplete, then carry over the remaining
// data to the next round of Decode().
if (!current_frame_header_.get())
break;
first_chunk = true;
}
std::unique_ptr<WebSocketFrameChunk> frame_chunk =
DecodeFramePayload(first_chunk);
DCHECK(frame_chunk.get());
frame_chunks->push_back(std::move(frame_chunk));
if (current_frame_header_.get()) {
DCHECK(current_read_pos_ == buffer_.size());
break;
}
}
// Drain unnecessary data. TODO(yutak): Remove copy. (but how?)
buffer_.erase(buffer_.begin(), buffer_.begin() + current_read_pos_);
current_read_pos_ = 0;
// Sanity check: the size of carried-over data should not exceed
// the maximum possible length of a frame header.
static const size_t kMaximumFrameHeaderSize =
WebSocketFrameHeader::kBaseHeaderSize +
WebSocketFrameHeader::kMaximumExtendedLengthSize +
WebSocketFrameHeader::kMaskingKeyLength;
DCHECK_LT(buffer_.size(), kMaximumFrameHeaderSize);
return true;
}
void WebSocketFrameParser::DecodeFrameHeader() {
typedef WebSocketFrameHeader::OpCode OpCode;
static const int kMaskingKeyLength = WebSocketFrameHeader::kMaskingKeyLength;
DCHECK(!current_frame_header_.get());
const char* start = &buffer_.front() + current_read_pos_;
const char* current = start;
const char* end = &buffer_.front() + buffer_.size();
// Header needs 2 bytes at minimum.
if (end - current < 2)
return;
uint8_t first_byte = *current++;
uint8_t second_byte = *current++;
bool final = (first_byte & kFinalBit) != 0;
bool reserved1 = (first_byte & kReserved1Bit) != 0;
bool reserved2 = (first_byte & kReserved2Bit) != 0;
bool reserved3 = (first_byte & kReserved3Bit) != 0;
OpCode opcode = first_byte & kOpCodeMask;
bool masked = (second_byte & kMaskBit) != 0;
uint64_t payload_length = second_byte & kPayloadLengthMask;
if (payload_length == kPayloadLengthWithTwoByteExtendedLengthField) {
if (end - current < 2)
return;
uint16_t payload_length_16;
base::ReadBigEndian(current, &payload_length_16);
current += 2;
payload_length = payload_length_16;
if (payload_length <= kMaxPayloadLengthWithoutExtendedLengthField)
websocket_error_ = kWebSocketErrorProtocolError;
} else if (payload_length == kPayloadLengthWithEightByteExtendedLengthField) {
if (end - current < 8)
return;
base::ReadBigEndian(current, &payload_length);
current += 8;
if (payload_length <= UINT16_MAX ||
payload_length > static_cast<uint64_t>(INT64_MAX)) {
websocket_error_ = kWebSocketErrorProtocolError;
} else if (payload_length > static_cast<uint64_t>(INT32_MAX)) {
websocket_error_ = kWebSocketErrorMessageTooBig;
}
}
if (websocket_error_ != kWebSocketNormalClosure) {
buffer_.clear();
current_read_pos_ = 0;
current_frame_header_.reset();
frame_offset_ = 0;
return;
}
if (masked) {
if (end - current < kMaskingKeyLength)
return;
std::copy(current, current + kMaskingKeyLength, masking_key_.key);
current += kMaskingKeyLength;
} else {
std::fill(masking_key_.key, masking_key_.key + kMaskingKeyLength, '\0');
}
current_frame_header_ = std::make_unique<WebSocketFrameHeader>(opcode);
current_frame_header_->final = final;
current_frame_header_->reserved1 = reserved1;
current_frame_header_->reserved2 = reserved2;
current_frame_header_->reserved3 = reserved3;
current_frame_header_->masked = masked;
current_frame_header_->payload_length = payload_length;
current_read_pos_ += current - start;
DCHECK_EQ(0u, frame_offset_);
}
std::unique_ptr<WebSocketFrameChunk> WebSocketFrameParser::DecodeFramePayload(
bool first_chunk) {
// The cast here is safe because |payload_length| is already checked to be
// less than std::numeric_limits<int>::max() when the header is parsed.
int next_size = static_cast<int>(
std::min(static_cast<uint64_t>(buffer_.size() - current_read_pos_),
current_frame_header_->payload_length - frame_offset_));
auto frame_chunk = std::make_unique<WebSocketFrameChunk>();
if (first_chunk) {
frame_chunk->header = current_frame_header_->Clone();
}
frame_chunk->final_chunk = false;
if (next_size) {
frame_chunk->data =
base::MakeRefCounted<IOBufferWithSize>(static_cast<int>(next_size));
char* io_data = frame_chunk->data->data();
memcpy(io_data, &buffer_.front() + current_read_pos_, next_size);
if (current_frame_header_->masked) {
// The masking function is its own inverse, so we use the same function to
// unmask as to mask.
MaskWebSocketFramePayload(
masking_key_, frame_offset_, io_data, next_size);
}
current_read_pos_ += next_size;
frame_offset_ += next_size;
}
DCHECK_LE(frame_offset_, current_frame_header_->payload_length);
if (frame_offset_ == current_frame_header_->payload_length) {
frame_chunk->final_chunk = true;
current_frame_header_.reset();
frame_offset_ = 0;
}
return frame_chunk;
}
} // namespace net