1 // Copyright 2014 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #include "components/cast_channel/cast_framer.h"
11 #include "base/memory/free_deleter.h"
12 #include "base/numerics/safe_conversions.h"
13 #include "base/strings/string_number_conversions.h"
14 #include "base/sys_byteorder.h"
15 #include "components/cast_channel/proto/cast_channel.pb.h"
17 namespace cast_channel {
18 MessageFramer::MessageFramer(scoped_refptr<net::GrowableIOBuffer> input_buffer)
19 : input_buffer_(input_buffer), error_(false) {
23 MessageFramer::~MessageFramer() {}
25 MessageFramer::MessageHeader::MessageHeader() : message_size(0) {}
27 void MessageFramer::MessageHeader::SetMessageSize(size_t size) {
28 DCHECK_LT(size, static_cast<size_t>(std::numeric_limits<uint32_t>::max()));
33 // TODO(mfoltz): Investigate replacing header serialization with base::Pickle,
34 // if bit-for-bit compatible.
35 void MessageFramer::MessageHeader::PrependToString(std::string* str) {
36 MessageHeader output = *this;
37 output.message_size = base::HostToNet32(message_size);
38 size_t header_size = MessageHeader::header_size();
39 std::unique_ptr<char, base::FreeDeleter> char_array(
40 static_cast<char*>(malloc(header_size)));
41 memcpy(char_array.get(), &output, header_size);
42 str->insert(0, char_array.get(), header_size);
45 // TODO(mfoltz): Investigate replacing header deserialization with base::Pickle,
46 // if bit-for-bit compatible.
47 void MessageFramer::MessageHeader::Deserialize(char* data,
48 MessageHeader* header) {
49 uint32_t message_size;
50 memcpy(&message_size, data, header_size());
51 header->message_size =
52 base::checked_cast<size_t>(base::NetToHost32(message_size));
56 size_t MessageFramer::MessageHeader::header_size() {
57 return sizeof(uint32_t);
61 size_t MessageFramer::MessageHeader::max_body_size() {
66 size_t MessageFramer::MessageHeader::max_message_size() {
67 return header_size() + max_body_size();
70 std::string MessageFramer::MessageHeader::ToString() {
71 return "{message_size: " +
72 base::UintToString(static_cast<uint32_t>(message_size)) + "}";
76 bool MessageFramer::Serialize(const CastMessage& message_proto,
77 std::string* message_data) {
79 message_proto.SerializeToString(message_data);
80 size_t message_size = message_data->size();
81 if (message_size > MessageHeader::max_body_size()) {
82 message_data->clear();
86 header.SetMessageSize(message_size);
87 header.PrependToString(message_data);
91 size_t MessageFramer::BytesRequested() {
97 switch (current_element_) {
99 bytes_left = MessageHeader::header_size() - message_bytes_received_;
100 DCHECK_LE(bytes_left, MessageHeader::header_size());
101 VLOG(2) << "Bytes needed for header: " << bytes_left;
105 (body_size_ + MessageHeader::header_size()) - message_bytes_received_;
106 DCHECK_LE(bytes_left, MessageHeader::max_body_size());
107 VLOG(2) << "Bytes needed for body: " << bytes_left;
110 NOTREACHED() << "Unhandled packet element type.";
115 std::unique_ptr<CastMessage> MessageFramer::Ingest(size_t num_bytes,
116 size_t* message_length,
117 ChannelError* error) {
119 DCHECK(message_length);
121 *error = ChannelError::INVALID_MESSAGE;
125 DCHECK_EQ(base::checked_cast<int32_t>(message_bytes_received_),
126 input_buffer_->offset());
127 CHECK_LE(num_bytes, BytesRequested());
128 message_bytes_received_ += num_bytes;
129 *error = ChannelError::NONE;
131 switch (current_element_) {
133 if (BytesRequested() == 0) {
134 MessageHeader header;
135 MessageHeader::Deserialize(input_buffer_->StartOfBuffer(), &header);
136 if (header.message_size > MessageHeader::max_body_size()) {
137 VLOG(1) << "Error parsing header (message size too large).";
138 *error = ChannelError::INVALID_MESSAGE;
142 current_element_ = BODY;
143 body_size_ = header.message_size;
147 if (BytesRequested() == 0) {
148 std::unique_ptr<CastMessage> parsed_message(new CastMessage);
149 if (!parsed_message->ParseFromArray(
150 input_buffer_->StartOfBuffer() + MessageHeader::header_size(),
152 VLOG(1) << "Error parsing packet body.";
153 *error = ChannelError::INVALID_MESSAGE;
157 *message_length = body_size_;
159 return parsed_message;
163 NOTREACHED() << "Unhandled packet element type.";
167 input_buffer_->set_offset(message_bytes_received_);
171 void MessageFramer::Reset() {
172 current_element_ = HEADER;
173 message_bytes_received_ = 0;
175 input_buffer_->set_offset(0);
178 } // namespace cast_channel