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| 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. | |
| 4 | |
| 5 #include "components/cast_channel/cast_framer.h" | |
| 6 | |
| 7 #include <stdlib.h> | |
| 8 | |
| 9 #include <limits> | |
| 10 | |
| 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" | |
| 16 | |
| 17 namespace cast_channel { | |
| 18 MessageFramer::MessageFramer(scoped_refptr<net::GrowableIOBuffer> input_buffer) | |
| 19 : input_buffer_(input_buffer), error_(false) { | |
| 20 Reset(); | |
| 21 } | |
| 22 | |
| 23 MessageFramer::~MessageFramer() {} | |
| 24 | |
| 25 MessageFramer::MessageHeader::MessageHeader() : message_size(0) {} | |
| 26 | |
| 27 void MessageFramer::MessageHeader::SetMessageSize(size_t size) { | |
| 28 DCHECK_LT(size, static_cast<size_t>(std::numeric_limits<uint32_t>::max())); | |
| 29 DCHECK_GT(size, 0U); | |
| 30 message_size = size; | |
| 31 } | |
| 32 | |
| 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); | |
| 43 } | |
| 44 | |
| 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)); | |
| 53 } | |
| 54 | |
| 55 // static | |
| 56 size_t MessageFramer::MessageHeader::header_size() { | |
| 57 return sizeof(uint32_t); | |
| 58 } | |
| 59 | |
| 60 // static | |
| 61 size_t MessageFramer::MessageHeader::max_message_size() { | |
| 62 return 65535; | |
| 63 } | |
| 64 | |
| 65 std::string MessageFramer::MessageHeader::ToString() { | |
| 66 return "{message_size: " + | |
| 67 base::UintToString(static_cast<uint32_t>(message_size)) + "}"; | |
| 68 } | |
| 69 | |
| 70 // static | |
| 71 bool MessageFramer::Serialize(const CastMessage& message_proto, | |
| 72 std::string* message_data) { | |
| 73 DCHECK(message_data); | |
| 74 message_proto.SerializeToString(message_data); | |
| 75 size_t message_size = message_data->size(); | |
| 76 if (message_size > MessageHeader::max_message_size()) { | |
| 77 message_data->clear(); | |
| 78 return false; | |
| 79 } | |
| 80 MessageHeader header; | |
| 81 header.SetMessageSize(message_size); | |
| 82 header.PrependToString(message_data); | |
| 83 return true; | |
| 84 } | |
| 85 | |
| 86 size_t MessageFramer::BytesRequested() { | |
| 87 size_t bytes_left; | |
| 88 if (error_) { | |
| 89 return 0; | |
| 90 } | |
| 91 | |
| 92 switch (current_element_) { | |
| 93 case HEADER: | |
| 94 bytes_left = MessageHeader::header_size() - message_bytes_received_; | |
| 95 DCHECK_LE(bytes_left, MessageHeader::header_size()); | |
| 96 VLOG(2) << "Bytes needed for header: " << bytes_left; | |
| 97 return bytes_left; | |
| 98 case BODY: | |
| 99 bytes_left = | |
| 100 (body_size_ + MessageHeader::header_size()) - message_bytes_received_; | |
| 101 DCHECK_LE(bytes_left, MessageHeader::max_message_size() - | |
| 102 MessageHeader::header_size()); | |
| 103 VLOG(2) << "Bytes needed for body: " << bytes_left; | |
| 104 return bytes_left; | |
| 105 default: | |
| 106 NOTREACHED() << "Unhandled packet element type."; | |
| 107 return 0; | |
| 108 } | |
| 109 } | |
| 110 | |
| 111 std::unique_ptr<CastMessage> MessageFramer::Ingest(size_t num_bytes, | |
| 112 size_t* message_length, | |
| 113 ChannelError* error) { | |
| 114 DCHECK(error); | |
| 115 DCHECK(message_length); | |
| 116 if (error_) { | |
| 117 *error = ChannelError::INVALID_MESSAGE; | |
| 118 return nullptr; | |
| 119 } | |
| 120 | |
| 121 DCHECK_EQ(base::checked_cast<int32_t>(message_bytes_received_), | |
| 122 input_buffer_->offset()); | |
| 123 CHECK_LE(num_bytes, BytesRequested()); | |
| 124 message_bytes_received_ += num_bytes; | |
| 125 *error = ChannelError::NONE; | |
| 126 *message_length = 0; | |
| 127 switch (current_element_) { | |
| 128 case HEADER: | |
| 129 if (BytesRequested() == 0) { | |
| 130 MessageHeader header; | |
| 131 MessageHeader::Deserialize(input_buffer_->StartOfBuffer(), &header); | |
| 132 if (header.message_size > MessageHeader::max_message_size()) { | |
| 133 VLOG(1) << "Error parsing header (message size too large)."; | |
| 134 *error = ChannelError::INVALID_MESSAGE; | |
| 135 error_ = true; | |
| 136 return nullptr; | |
| 137 } | |
| 138 current_element_ = BODY; | |
| 139 body_size_ = header.message_size; | |
| 140 } | |
| 141 break; | |
| 142 case BODY: | |
| 143 if (BytesRequested() == 0) { | |
| 144 std::unique_ptr<CastMessage> parsed_message(new CastMessage); | |
| 145 if (!parsed_message->ParseFromArray( | |
| 146 input_buffer_->StartOfBuffer() + MessageHeader::header_size(), | |
| 147 body_size_)) { | |
| 148 VLOG(1) << "Error parsing packet body."; | |
| 149 *error = ChannelError::INVALID_MESSAGE; | |
| 150 error_ = true; | |
| 151 return nullptr; | |
| 152 } | |
| 153 *message_length = body_size_; | |
| 154 Reset(); | |
| 155 return parsed_message; | |
| 156 } | |
| 157 break; | |
| 158 default: | |
| 159 NOTREACHED() << "Unhandled packet element type."; | |
| 160 return nullptr; | |
| 161 } | |
| 162 | |
| 163 input_buffer_->set_offset(message_bytes_received_); | |
| 164 return nullptr; | |
| 165 } | |
| 166 | |
| 167 void MessageFramer::Reset() { | |
| 168 current_element_ = HEADER; | |
| 169 message_bytes_received_ = 0; | |
| 170 body_size_ = 0; | |
| 171 input_buffer_->set_offset(0); | |
| 172 } | |
| 173 | |
| 174 } // namespace cast_channel | |
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