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 "base/macros.h"
+#include "net/base/io_buffer.h"
+
+namespace device {
+class U2fPacket : public base::RefCountedThreadSafe<U2fPacket> {
+ public:
+  U2fPacket(const std::vector<uint8_t> data, const uint8_t channel_id[]);

[juanlang (chromium.org), 2016/12/07 18:29:26]

Same comment about passing channel_id as a uint32_t rather than an array.

[Casey Piper, 2016/12/09 00:15:54]

Done.

+
+  scoped_refptr<net::IOBufferWithSize> GetBuffer();

[juanlang (chromium.org), 2016/12/07 18:29:26]

What's the difference between GetBuffer() and GetData()? I mean, I can imagine
they refer to the two different member variables, but I'm confused by what the
distinction between the two could be.

[Casey Piper, 2016/12/09 00:15:54]

I'll change it and hopefully they'll be more clear. GetData in this case returns
the payload data (so the non-header data in a packet), while GetBuffer returns
the entire packet in serialized IOBuffer form.

+  const std::vector<uint8_t> GetData();
+  uint8_t* GetChannelId();
+
+  static const size_t kChannelIdSize = 4;

[juanlang (chromium.org), 2016/12/07 18:29:26]

If you use uint32_t for the channel_id, I don't think you need this any longer.

[Casey Piper, 2016/12/09 00:15:54]

Done.

+  // Packet size of 64 bytes + 1 byte report ID
+  static const size_t kPacketSize = 65;

[juanlang (chromium.org), 2016/12/07 18:29:26]

Seems like an implementation detail that could be not public.

[Casey Piper, 2016/12/09 00:15:54]

Moved to protected.

+
+ protected:
+  U2fPacket();
+  virtual ~U2fPacket();
+
+  std::vector<uint8_t> data_;
+  uint8_t channel_id_[kChannelIdSize];
+  scoped_refptr<net::IOBufferWithSize> serialized_;
+
+ private:
+  friend class base::RefCountedThreadSafe<U2fPacket>;
+};
+
+class U2fInitPacket : public U2fPacket {
+ public:
+  U2fInitPacket(const uint8_t channel_id[kChannelIdSize],
+                const uint8_t cmd,
+                const std::vector<uint8_t> data,
+                const uint16_t payload_length);
+
+  static scoped_refptr<U2fInitPacket> Create(
+      scoped_refptr<net::IOBufferWithSize> buf,
+      size_t* remaining_size);
+  uint8_t GetCommand();
+  uint16_t GetPayloadLength();
+
+ protected:
+  ~U2fInitPacket() final;
+
+ private:
+  U2fInitPacket(scoped_refptr<net::IOBufferWithSize> buf,
+                size_t* remaining_size);
+
+  uint8_t command_;
+  uint16_t payload_length_;
+};
+
+class U2fContPacket : public U2fPacket {
+ public:
+  U2fContPacket(const uint8_t channel_id[kChannelIdSize],
+                const uint8_t sequence,
+                std::vector<uint8_t> data);
+  static scoped_refptr<U2fContPacket> Create(
+      scoped_refptr<net::IOBufferWithSize> buf,
+      size_t* remaining_size);
+
+  uint8_t GetSequence();
+
+ protected:
+  ~U2fContPacket() final;
+
+ private:
+  U2fContPacket(scoped_refptr<net::IOBufferWithSize> buf,
+                size_t* remaining_size);
+
+  uint8_t sequence_;
+};
+}  // namespace device
+
+#endif  // DEVICE_U2F_U2F_PACKET_H_