Add FIDO U2F message and packet classes

device/u2f/u2f_packet.h

+// Copyright 2016 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.
+
+#ifndef DEVICE_U2F_U2F_PACKET_H_
+#define DEVICE_U2F_U2F_PACKET_H_
+
+#include <algorithm>
+#include <vector>
+
+#include "base/macros.h"
+#include "net/base/io_buffer.h"

[pauljensen, 2016/12/15 01:59:22]

Can this be replaced with a forward declaration?  this is the Chromium prefered
style:
https://chromium.googlesource.com/chromium/src/+/master/styleguide/c++/c++.md...

[Casey Piper, 2016/12/15 18:34:17]

Done.

+
+namespace device {
+
+// U2fPackets are defined by the specification at
+// http://fidoalliance.org/specs/u2f-specs-1.0-bt-nfc-id-amendment/fido-u2f-hid-protocol.html
+// Packets are one of two types, initialization packets and continuation
+// packets,
+// (U2fInitPacket and U2fContinuationPacket). U2fPackets have header information
+// and a payload. If a U2fInitPacket cannot store the entire payload, further
+// payload information is stored in U2fContinuationPackets.
+class U2fPacket : public base::RefCountedThreadSafe<U2fPacket> {
+ public:
+  U2fPacket(const std::vector<uint8_t> data, uint32_t channel_id);
+
+  scoped_refptr<net::IOBufferWithSize> GetSerializedBuffer();
+  std::vector<uint8_t> GetPacketPayload() const;
+  uint32_t channel_id() { return channel_id_; }
+
+ protected:
+  U2fPacket();
+  virtual ~U2fPacket();
+
+  // Packet size of 64 bytes + 1 byte report ID
+  static constexpr size_t kPacketSize = 65;
+  std::vector<uint8_t> data_;
+  uint32_t channel_id_;
+  scoped_refptr<net::IOBufferWithSize> serialized_;
+
+ private:
+  friend class base::RefCountedThreadSafe<U2fPacket>;
+  friend class U2fMessage;
+};
+
+// U2fInitPacket, based on the U2f specification consists of a header with data
+// that is serialized into a IOBuffer. A channel identifier is allocated by the
+// U2F device to ensure its system-wide uniqueness. Command identifiers
+// determine the type of message the packet corresponds to. Payload length
+// is the length of the entire message payload, and the data is only the portion
+// of the payload that will fit into the U2fInitPacket.
+class U2fInitPacket : public U2fPacket {
+ public:
+  U2fInitPacket(uint32_t channel_id,
+                uint8_t cmd,
+                const std::vector<uint8_t> data,
+                uint16_t payload_length);
+
+  // Creates a packet from the serialized data of an initialization packet. As
+  // this is the first packet, the payload length of the entire message will be
+  // included within the serialized data. Remaining size will be returned to
+  // inform the callee how many additional packets to expect.
+  static scoped_refptr<U2fInitPacket> CreateFromSerializedData(
+      scoped_refptr<net::IOBufferWithSize> buf,
+      size_t* remaining_size);
+  uint8_t command() { return command_; }
+  uint16_t payload_length() { return payload_length_; }
+
+ protected:
+  ~U2fInitPacket() final;
+
+ private:
+  U2fInitPacket(scoped_refptr<net::IOBufferWithSize> buf,
+                size_t* remaining_size);
+
+  uint8_t command_;
+  uint16_t payload_length_;
+};
+
+// U2fContinuationPacket, based on the U2f Specification consists of a header
+// with data that is serialized into an IOBuffer. The channel identifier will
+// be identical to the identifier in all other packets of the message. The
+// packet sequence will be the sequence number of this particular packet, from
+// 0x00 to 0x7f.
+class U2fContinuationPacket : public U2fPacket {
+ public:
+  U2fContinuationPacket(const uint32_t channel_id,
+                        const uint8_t sequence,
+                        std::vector<uint8_t> data);
+
+  // Creates a packet from the serialized data of a continuation packet. As an
+  // U2fInitPacket would have arrived earlier with the total payload size,
+  // the remaining size should be passed to inform the packet of how much data
+  // to expect.
+  static scoped_refptr<U2fContinuationPacket> CreateFromSerializedData(
+      scoped_refptr<net::IOBufferWithSize> buf,
+      size_t* remaining_size);
+  uint8_t sequence() { return sequence_; }
+
+ protected:
+  ~U2fContinuationPacket() final;
+
+ private:
+  U2fContinuationPacket(scoped_refptr<net::IOBufferWithSize> buf,
+                        size_t* remaining_size);
+
+  uint8_t sequence_;
+};
+}  // namespace device
+
+#endif  // DEVICE_U2F_U2F_PACKET_H_