Add FIDO U2F message and packet classes

device/u2f/u2f_message.h

Index: device/u2f/u2f_message.h
diff --git a/device/u2f/u2f_message.h b/device/u2f/u2f_message.h
new file mode 100644
index 0000000000000000000000000000000000000000..5642c002813b074d0351fe7ea0ca9a0746864b29
--- /dev/null
+++ b/device/u2f/u2f_message.h
@@ -0,0 +1,65 @@
+// 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_MESSAGE_H_
+#define DEVICE_U2F_U2F_MESSAGE_H_
+
+#include <list>
+#include <vector>
+#include "base/macros.h"
+#include "device/u2f/u2f_packet.h"
+
+namespace device {
+
+class U2fMessage : public base::RefCountedThreadSafe<U2fMessage> {
+ public:
+  enum class Type : uint8_t {

[juanlang (chromium.org), 2016/11/30 19:41:32]

It'd be helpful to reference the U2F specs somewhere in this file, e.g.
http://fidoalliance.org/specs/u2f-specs-1.0-bt-nfc-id-amendment/fido-u2f-hid-....

+    CMD_PING = 0x81,
+    CMD_ATR = 0x82,

[juanlang (chromium.org), 2016/11/30 19:41:32]

This is not part of the U2F HID standard, please remove.

[Casey Piper, 2016/11/30 22:05:46]

Done.

+    CMD_APDU = 0x83,

[juanlang (chromium.org), 2016/11/30 19:41:32]

In the U2F HID standard, this is known as MSG rather than APDU.

[Casey Piper, 2016/11/30 22:05:46]

Done.

+    CMD_LOCK = 0x84,

[juanlang (chromium.org), 2016/11/30 19:41:32]

This is not part of the U2F HID standard, please remove.

[Casey Piper, 2016/11/30 22:05:46]

Done.

+    CMD_SYSINFO = 0x85,

[juanlang (chromium.org), 2016/11/30 19:41:32]

Ditto.

[Casey Piper, 2016/11/30 22:05:46]

Acknowledged.

+    CMD_INIT = 0x86,
+    CMD_PROMPT = 0x87,

[juanlang (chromium.org), 2016/11/30 19:41:32]

Ditto.

[Casey Piper, 2016/11/30 22:05:46]

Acknowledged.

+    CMD_WINK = 0x88,
+    CMD_BLE_UID = 0xb5,

[juanlang (chromium.org), 2016/11/30 19:41:32]

Ditto.

[Casey Piper, 2016/11/30 22:05:46]

Acknowledged.

+    CMD_USB_TEST = 0xb9,

[juanlang (chromium.org), 2016/11/30 19:41:32]

Ditto.

[Casey Piper, 2016/11/30 22:05:46]

Acknowledged.

+    CMD_DFU = 0xba,

[juanlang (chromium.org), 2016/11/30 19:41:32]

Ditto.

[Casey Piper, 2016/11/30 22:05:46]

Acknowledged.

+    CMD_SYNC = 0xbc,

[juanlang (chromium.org), 2016/11/30 19:41:32]

No action required, just an FYI:

This is not part of the U2F HID standard. On the other hand, it's used by the
Google-proprietary WinUSB protocol variant. Unless you already know you won't be
implementing support for these, it seems safe to leave it in, though maybe with
a TODO to remove once support for the proprietary protocol is removed.

[Casey Piper, 2016/11/30 22:05:46]

Acknowledged.

+    CMD_ERROR = 0xbf,
+  };
+
+  static const size_t kInitPacketHeader = 7;
+  static const size_t kContPacketHeader = 5;
+  static const size_t kInitPacketDataSize = 57;

[juanlang (chromium.org), 2016/11/30 19:41:32]

Funny that such a small line will generate this volume of comments! Grab some
popcorn, the show's about to begin.

This is the result of subtracting kInitPacketHeader from an implicit limit: the
maximum length of a HID packet (64 bytes.) I think it'd be clearer to make that
result explicit rather than implicit, i.e. to define a new constant
kMaxHidPacketSize and either define this limit in terms of it, or just use
subtraction when you need to.

However, see also my comment about the WinUSB protocol variant. If you intend to
support it (do you?), it might be better to leave the maximum packet length as
something the caller specifies, as the limit for an individual packet for the
WinUSB protocol is rather larger, perhaps 2k.

[Casey Piper, 2016/11/30 22:05:46]

Done.

+  static const size_t kContPacketDataSize = 59;
+
+  // Messages are limited to an init packet and 128 cont packets
+  // Maximum payload length therefore is 64-7 + 128 * (64-5) = 7609 bytes
+  static const size_t kMaxMessageSize = 7609;
+
+  static scoped_refptr<U2fMessage> Create(
+      const uint8_t channel_id[U2fPacket::kChannelIdSize],
+      const Type type,
+      const std::vector<uint8_t>& data);
+
+  scoped_refptr<net::IOBufferWithSize> GetNextPacket();
+  size_t NumPackets();
+
+  std::list<scoped_refptr<U2fPacket>>::const_iterator begin();
+  std::list<scoped_refptr<U2fPacket>>::const_iterator end();
+
+ private:
+  friend class base::RefCountedThreadSafe<U2fMessage>;
+  std::list<scoped_refptr<U2fPacket>> packets_;
+  U2fMessage(const uint8_t channel_id[U2fPacket::kChannelIdSize],
+             const Type type,
+             const std::vector<uint8_t>& data);

[Reilly Grant (use Gerrit), 2016/11/30 20:53:46]

Keep these definitions in order with blank lines between: friends, typedefs,
constructors, methods, fields.

[Casey Piper, 2016/11/30 22:05:46]

Acknowledged.

+
+ protected:
+  virtual ~U2fMessage();

[Reilly Grant (use Gerrit), 2016/11/30 20:53:46]

Protected before private.

[Casey Piper, 2016/11/30 22:05:46]

Acknowledged.

+};
+}  // namespace device
+
+#endif  // DEVICE_U2F_U2F_MESSAGE_H_