Re: PATCH: Support for Bluetooth NAP devices

["Nathaniel McCallum" <nathaniel natemccallum com>]

On Tue, May 13, 2008 at 4:11 PM, Dan Williams <dcbw redhat com> wrote:
> On Sat, 2008-05-10 at 14:42 -0700, Nathaniel McCallum wrote:
>  > Bluetooth NAP devices are pretty simple really.   You connect and (at
>  > least in Linux) they emulate an ethernet device.
>
>  Can you send me the lshal output for when you've got one of these
>  devices plugged in?
>
>  Also, what sets up the device?  How do you pair it?  When you plug it
>  in, do you need to do any additional setup on the device before it has a
>  bnepX interface?

Unfortunately, I left my cell phone at home.  I'll have to provide
lshal output later.  However, I don't really think it is necessary.

An Access Point is to wifi what a NAP (Network Access Point) is to bluetooth.

The major differences is that for wifi the interface (ex. wlan0)
pre-exists the wireless connection, while for bluetooth the interface
(bnep0) has the same lifecycle as the wireless connection.  Once the
connection is established via Bluez (bnep), the pseudo-Ethernet
interface is created.  If the connection is torn down, the interface
disappears.  While the interface exists, it is treated exactly like a
normal Ethernet interface.

When the bnep interface is created, HAL creates two new objects.  HAL
does NOT report this as an ethernet device because, in reality, it
isn't.  So instead of 'net.80203' occurring in both the
info.capability and info.category keys, 'net.bluetooth' appears.  HAL
also does not report the driver because in every case this type of
device will use the bnep module. So my patch basically tells
NetworkManager: assume 'net.bluetooth' == 'net.80203'.

The FDI file makes HAL report the driver name (which will ALWAYS be
'bnep' on this type of device).  This FDI should not be in upstream
HAL because it is really specific to NM's usage of HAL. I'll leave it
up to you to determine if NM's behaviour in this regard is correct.
If it is correct, than the FDI file will need to be installed with NM.
 If it is not correct, then fix NM and the FDI file can be ignored.

I hope this makes sense.  Ideally, NM should treat each bluetooth
adapter (hci) as an "interface" (even though there is no interface)
and have NAP presence detection (similar to scanning for wifi APs).
However, this is non-trivial, and may not even be desirable.  However,
with this trivial patch, NetworkManager can work with these devices
NOW, it just requires that the connection be established outside of NM
(via bluez pand or the bluez network service).

Nathaniel