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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 "extensions/browser/api/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 "extensions/common/api/cast_channel/cast_channel.pb.h" | |
16 | |
17 namespace extensions { | |
18 namespace api { | |
19 namespace cast_channel { | |
20 MessageFramer::MessageFramer(scoped_refptr<net::GrowableIOBuffer> input_buffer) | |
21 : input_buffer_(input_buffer), error_(false) { | |
22 Reset(); | |
23 } | |
24 | |
25 MessageFramer::~MessageFramer() { | |
26 } | |
27 | |
28 MessageFramer::MessageHeader::MessageHeader() : message_size(0) { | |
29 } | |
30 | |
31 void MessageFramer::MessageHeader::SetMessageSize(size_t size) { | |
32 DCHECK_LT(size, static_cast<size_t>(std::numeric_limits<uint32_t>::max())); | |
33 DCHECK_GT(size, 0U); | |
34 message_size = size; | |
35 } | |
36 | |
37 // TODO(mfoltz): Investigate replacing header serialization with base::Pickle, | |
38 // if bit-for-bit compatible. | |
39 void MessageFramer::MessageHeader::PrependToString(std::string* str) { | |
40 MessageHeader output = *this; | |
41 output.message_size = base::HostToNet32(message_size); | |
42 size_t header_size = MessageHeader::header_size(); | |
43 std::unique_ptr<char, base::FreeDeleter> char_array( | |
44 static_cast<char*>(malloc(header_size))); | |
45 memcpy(char_array.get(), &output, header_size); | |
46 str->insert(0, char_array.get(), header_size); | |
47 } | |
48 | |
49 // TODO(mfoltz): Investigate replacing header deserialization with base::Pickle, | |
50 // if bit-for-bit compatible. | |
51 void MessageFramer::MessageHeader::Deserialize(char* data, | |
52 MessageHeader* header) { | |
53 uint32_t message_size; | |
54 memcpy(&message_size, data, header_size()); | |
55 header->message_size = | |
56 base::checked_cast<size_t>(base::NetToHost32(message_size)); | |
57 } | |
58 | |
59 // static | |
60 size_t MessageFramer::MessageHeader::header_size() { | |
61 return sizeof(uint32_t); | |
62 } | |
63 | |
64 // static | |
65 size_t MessageFramer::MessageHeader::max_message_size() { | |
66 return 65535; | |
67 } | |
68 | |
69 std::string MessageFramer::MessageHeader::ToString() { | |
70 return "{message_size: " + | |
71 base::UintToString(static_cast<uint32_t>(message_size)) + "}"; | |
72 } | |
73 | |
74 // static | |
75 bool MessageFramer::Serialize(const CastMessage& message_proto, | |
76 std::string* message_data) { | |
77 DCHECK(message_data); | |
78 message_proto.SerializeToString(message_data); | |
79 size_t message_size = message_data->size(); | |
80 if (message_size > MessageHeader::max_message_size()) { | |
81 message_data->clear(); | |
82 return false; | |
83 } | |
84 MessageHeader header; | |
85 header.SetMessageSize(message_size); | |
86 header.PrependToString(message_data); | |
87 return true; | |
88 } | |
89 | |
90 size_t MessageFramer::BytesRequested() { | |
91 size_t bytes_left; | |
92 if (error_) { | |
93 return 0; | |
94 } | |
95 | |
96 switch (current_element_) { | |
97 case HEADER: | |
98 bytes_left = MessageHeader::header_size() - message_bytes_received_; | |
99 DCHECK_LE(bytes_left, MessageHeader::header_size()); | |
100 VLOG(2) << "Bytes needed for header: " << bytes_left; | |
101 return bytes_left; | |
102 case BODY: | |
103 bytes_left = | |
104 (body_size_ + MessageHeader::header_size()) - message_bytes_received_; | |
105 DCHECK_LE( | |
106 bytes_left, | |
107 MessageHeader::max_message_size() - MessageHeader::header_size()); | |
108 VLOG(2) << "Bytes needed for body: " << bytes_left; | |
109 return bytes_left; | |
110 default: | |
111 NOTREACHED() << "Unhandled packet element type."; | |
112 return 0; | |
113 } | |
114 } | |
115 | |
116 std::unique_ptr<CastMessage> MessageFramer::Ingest(size_t num_bytes, | |
117 size_t* message_length, | |
118 ChannelError* error) { | |
119 DCHECK(error); | |
120 DCHECK(message_length); | |
121 if (error_) { | |
122 *error = ChannelError::INVALID_MESSAGE; | |
123 return nullptr; | |
124 } | |
125 | |
126 DCHECK_EQ(base::checked_cast<int32_t>(message_bytes_received_), | |
127 input_buffer_->offset()); | |
128 CHECK_LE(num_bytes, BytesRequested()); | |
129 message_bytes_received_ += num_bytes; | |
130 *error = ChannelError::NONE; | |
131 *message_length = 0; | |
132 switch (current_element_) { | |
133 case HEADER: | |
134 if (BytesRequested() == 0) { | |
135 MessageHeader header; | |
136 MessageHeader::Deserialize(input_buffer_->StartOfBuffer(), &header); | |
137 if (header.message_size > MessageHeader::max_message_size()) { | |
138 VLOG(1) << "Error parsing header (message size too large)."; | |
139 *error = ChannelError::INVALID_MESSAGE; | |
140 error_ = true; | |
141 return nullptr; | |
142 } | |
143 current_element_ = BODY; | |
144 body_size_ = header.message_size; | |
145 } | |
146 break; | |
147 case BODY: | |
148 if (BytesRequested() == 0) { | |
149 std::unique_ptr<CastMessage> parsed_message(new CastMessage); | |
150 if (!parsed_message->ParseFromArray( | |
151 input_buffer_->StartOfBuffer() + MessageHeader::header_size(), | |
152 body_size_)) { | |
153 VLOG(1) << "Error parsing packet body."; | |
154 *error = ChannelError::INVALID_MESSAGE; | |
155 error_ = true; | |
156 return nullptr; | |
157 } | |
158 *message_length = body_size_; | |
159 Reset(); | |
160 return parsed_message; | |
161 } | |
162 break; | |
163 default: | |
164 NOTREACHED() << "Unhandled packet element type."; | |
165 return nullptr; | |
166 } | |
167 | |
168 input_buffer_->set_offset(message_bytes_received_); | |
169 return nullptr; | |
170 } | |
171 | |
172 void MessageFramer::Reset() { | |
173 current_element_ = HEADER; | |
174 message_bytes_received_ = 0; | |
175 body_size_ = 0; | |
176 input_buffer_->set_offset(0); | |
177 } | |
178 | |
179 } // namespace cast_channel | |
180 } // namespace api | |
181 } // namespace extensions | |
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