1. Introduction
What is Bluetooth?

Bluetooth is an industrial specification that provides users a way to connect
and exchange information between devices like personal computers, PDAs or
mobile phones. Using the Bluetooth technology, users can achieve wireless voice
and data transmission between devices at a low cost. Bluetooth also offers the
possibility to create small wireless LANs and to synchronize devices.

About the content of this guide

The first part of this guide is to identify qualified and non-qualified devices
that support the Bluetooth technology. This way, users can purchase Bluetooth
devices that are known to work. After that, the guide explains how to configure
the system kernel, identify the Bluetooth devices installed on the system and
detected by the kernel and install the necessary basic Bluetooth tools.

The second part covers how to detect remote devices and how to establish a
connection from or to them by either setting up radio frequency communication
(RFCOMM) or by setting up a personal area network (PAN).

The last part of the guide lists in detail applications that can take
advantage of all the possibilities offered by the Bluetooth technology.

2. Supported Devices
Qualified and non-qualified devices that support Bluetooth

Important:
These products might work even though some are not qualified Bluetooth
products. Gentoo does not support them in any way, they might just work.

A list of the currently supported devices can be found at: Bluetooth device
features and revision information by Marcel Holtmann.

3. Configuring the system
Kernel Configuration

As the latest Linux stable kernel is 2.6, the configuration will be done for
these series of the kernel. Most Bluetooth devices are connected to a USB port,
so USB will be enabled too. Please refer to the Gentoo Linux USB Guide.

Code Listing 3.1: Configuration for 2.6 kernels
Networking —>

<*> Bluetooth subsystem support —>

— Bluetooth subsystem support
L2CAP protocol support
SCO links support
RFCOMM protocol support
[*] RFCOMM TTY support
BNEP protocol support
[*] Multicast filter support
[*] Protocol filter support
HIDP protocol support

Bluetooth device drivers —>
HCI USB driver
[*] SCO (voice) support
HCI UART driver
[*] UART (H4) protocol support
[*] BCSP protocol support
[*] Transmit CRC with every BCSP packet
HCI BCM203x USB driver
HCI BPA10x USB driver
HCI BlueFRITZ! USB driver
(The four drivers below are for PCMCIA Bluetooth devices and will only
show up if you have also selected PCMCIA support in your kernel.)
HCI DTL1 (PC Card) driver
HCI BT3C (PC Card) driver
HCI BlueCard (PC Card) driver
HCI UART (PC Card) device driver
(The driver below is intended for HCI Emulation software.)
HCI VHCI (Virtual HCI device) driver

(Move back three levels to Device Drives and then check if USB is
enabled. This is required if you use a Bluetooth dongle, which are mostly USB
based.)
USB support —>

<*> Support for Host-side USB
— USB Host Controller Drivers
EHCI HCD (USB 2.0) support
[ ] Full speed ISO transactions (EXPERIMENTAL)
[ ] Root Hub Transaction Translators (EXPERIMENTAL)
<*> OHCI HCD support
<*> UHCI HCD (most Intel and VIA) support
< > SL811HS HCD support

Now we’ll reboot with our new kernel. If everything went fine, we will have a
system that is Bluetooth ready.

Important:
Your USB device may have two modes the default of which may not be HCI, but HID.
If this is your case, use hid2hci to switch to HCI mode. Your system
will not remember this change when you next reboot.

Code Listing 3.2: Checking the Bluetooth devices
(One way to check for the device)
# cat /proc/bus/usb/devices | grep -e^[TPD] | grep -e Cls=e0 -B1 -A1
(The Cls=e0(unk. ) identifies the Bluetooth adapter.)
T: Bus=02 Lev=02 Prnt=03 Port=00 Cnt=01 Dev#= 4 Spd=12 MxCh= 0
D: Ver= 1.10 Cls=e0(unk. ) Sub=01 Prot=01 MxPS=64 #Cfgs= 1
P: Vendor=0a12 ProdID=0001 Rev= 5.25
(Some might show up on lsusb from sys-apps/usbutils)
# lsusb
Bus 003 Device 002: ID 046d:c00e Logitech, Inc. Optical Mouse
Bus 003 Device 001: ID 0000:0000
Bus 002 Device 002: ID 0db0:1967 Micro Star International Bluetooth Dongle

4. BlueZ – The Bluetooth Stack
Installing BlueZ

Now that the device is detected by the kernel, we need a layer that lets
applications communicate with the Bluetooth device. BlueZ provides the official
Linux Bluetooth stack. The ebuilds that provide what we need are
bluez-libs and bluez-utils. Devices that need Broadcom firmware
files or the like may need bluez-firmware.

Code Listing 4.1: Installing bluez-libs and bluez-utils
# emerge net-wireless/bluez-libs net-wireless/bluez-utils

Warning:
Do not emerge bluez-sdp as it will break bluez-utils!

BlueZ configuration and PIN pairing

Now it’s time to see if the Bluetooth device is being picked up correctly by the
system. We start up the required Bluetooth services first.

Code Listing 4.2: Running hciconfig
(Start up Bluetooth)
# /etc/init.d/bluetooth start
* Starting Bluetooth …
* Starting hcid … [ ok ]
* Starting sdpd … [ ok ]
* Starting rfcomm … [ ok ]

# hciconfig
hci0: Type: USB
BD Address: 00:01:02:03:04:05 ACL MTU: 192:8 SCO MTU: 64:8
DOWN
RX bytes:131 acl:0 sco:0 events:18 errors:0
TX bytes:565 acl:0 sco:0 commands:17 errors:0

This shows that the Bluetooth device has been recognised. As you might have
noticed the device is DOWN. Let’s configure it so that we can bring it
up. The configuration file is at /etc/bluetooth/hcid.conf. The
required changes to the config file are shown below. For additional details
please refer to man hcid.conf.

Code Listing 4.3: Editing /etc/bluetooth/hcid.conf
(Recommended changes to be made to the file are shown)

# HCId options
options {
# Automatically initialize new devices
autoinit yes;

(Change security to “auto”)
# Security Manager mode
# none – Security manager disabled
# auto – Use local PIN for incoming connections
# user – Always ask user for a PIN
#
security auto;

# Pairing mode
pairing multi;

(You only need a pin helper if you are using <=bluez-libs-2.x and <=bluez-utils-2.x)
(Change pin_helper to use /etc/bluetooth/pin-helper)
# PIN helper
pin_helper /etc/bluetooth/pin-helper;
}

# Default settings for HCI devices
device {
(Set your device name here, you can call it anything you want)
# Local device name
# %d – device id
# %h – host name
name “BlueZ at %h (%d)”;

# Local device class
class 0x3e0100;

# Inquiry and Page scan
iscan enable; pscan enable;

# Default link mode
lm accept;

# Default link policy
lp rswitch,hold,sniff,park;

(Leave as is, if you don’t know what exactly these do)
# Authentication and Encryption (Security Mode 3)
#auth enable;
#encrypt enable;
}

After that, we have to configure the Bluetooth device PIN. That will help in
pairing this device with another one.

Code Listing 4.4: Editing /etc/bluetooth/pin
(Replace 123456 with your desired pin number.)
123456

Important:
This number (of your choice) must be the same in all your hosts with Bluetooth
devices so they can be paired. This number must also be kept secret since anyone
with knowledge of this number can essentially establish connections with your
devices.

Note:
If you are using <=bluez-libs-2.x and <=bluez-utils-2.x you
can choose from different pin helpers, depending on what you want to use.
Available pin helpers are: /usr/lib/kdebluetooth/kbluepin
(net-wireless/kdebluetooth), /usr/bin/bluepin or
/etc/bluetooth/pin-helper among others.

Note:
Beginning with >=bluez-libs-3.x and >=bluez-utils-3.x, pin helpers
have been replaced by passkey agents. There are a few different graphical
passkey agents available to help manage your PIN, such as bluez-gnome and
kdebluetooth. You can also use passkey-agent (found in
bluez-utils) from the command line.

Services configuration

Now that we have concluded with the configuration of BlueZ, it’s time to restart
the necessary services.

Code Listing 4.5: Starting the Bluetooth daemons
# /etc/init.d/bluetooth restart
(We can also add it to the default runlevel.)
# rc-update add bluetooth default
* bluetooth added to runlevel default
* rc-update complete.

Let’s be sure that the Bluetooth daemons started correctly. If we can see that
both hcid and sdpd are running, then we configured Bluetooth the
right way. After that, we can see if the devices are now up and running with
the configured options.

Code Listing 4.6: Checking whether Bluetooth daemons started correctly
(Check to see if the services are running)
# ps -ae | grep hcid
26050 ? 00:00:00 hcid
# ps -ae | grep sdpd
26054 ? 00:00:00 sdpd

# hciconfig -a
hci0: Type: USB
BD Address: 00:0A:0B:0C:0D:0E ACL MTU: 192:8 SCO MTU: 64:8
UP RUNNING PSCAN ISCAN
RX bytes:125 acl:0 sco:0 events:17 errors:0
TX bytes:565 acl:0 sco:0 commands:17 errors:0
Features: 0xff 0xff 0x0f 0×00 0×00 0×00 0×00 0×00
Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3
Link policy: RSWITCH HOLD SNIFF PARK
Link mode: SLAVE ACCEPT
Name: ‘BlueZ at bluehat (0)’
Class: 0x3e0100
Service Classes: Networking, Rendering, Capturing, Object Transfer,
Audio
Device Class: Computer, Uncategorized
HCI Ver: 1.1 (0×1) HCI Rev: 0x1e7 LMP Ver: 1.1 (0×1) LMP Subver: 0x1e7
Manufacturer: Cambridge Silicon Radio (10)

5. Detecting and Connecting to Remote Devices
Detecting Bluetooth devices in other hosts

At this point we are now ready to detect Bluetooth devices installed in other
machines. This is independent of the host Operating System. We will make use of
the hcitool command for the same.

Code Listing 5.1: Checking for local devices
# hcitool dev
Devices:
hci0 00:01:02:03:04:05

Code Listing 5.2: Scanning for remote devices
# hcitool scan
Scanning …
00:0A:0B:0C:0D:0E Grayhat

Code Listing 5.3: Inquiring remote devices
# hcitool inq
Inquiring …
00:0A:0B:0C:0D:0E clock offset: 0×5579 class: 0x72010c

Now that we know the MAC address of the remote Bluetooth devices, we can check
if we paired them correctly.

Code Listing 5.4: Running l2ping
# l2ping 00:0A:0B:0C:0D:0E
Ping: 00:0A:0B:0C:0D:0E from 00:01:02:03:04:05 (data size 20) …
20 bytes from 00:0A:0B:0C:0D:0E id 200 time 69.85ms
20 bytes from 00:0A:0B:0C:0D:0E id 201 time 9.97ms
20 bytes from 00:0A:0B:0C:0D:0E id 202 time 56.86ms
20 bytes from 00:0A:0B:0C:0D:0E id 203 time 39.92ms
4 sent, 4 received, 0% loss

Setting up Radio Frequency Communication (RFCOMM)

Note:
Please note that setting up radio frequency communication is optional.

We can establish a radio frequency connection to another Bluetooth device using
the rfcomm command. To make things a little easier especially for users
with multiple devices that support Bluetooth, it is advisable to make a few
changes to the default rfcomm config at /etc/bluetooth/rfcomm.conf.

The whole segment of the config starting from rfcomm0 { and ending with
} is the config for the device that will establish a connection at
/dev/rfcomm0. In this case, we will only show one example, rfcomm0.
You can add more devices as you see fit.

Code Listing 5.5: Editing /etc/bluetooth/rfcomm.conf
(Only changes that might be needed are shown)
rfcomm0 {
# Automatically bind the device at startup
(Creates the device node, /dev/rfcomm0 at start up)
bind yes;

# Bluetooth address of the device
(Enter the address of the device you want to connect to)
device 00:0A:0B:0C:0D:0E;

}

After configuring RFCOMM, we can connect to any device. Since we’ve made the
required settings to the /etc/bluetooth/rfcomm.conf file, we just
issue the command shown below. In case you’ve not made changes to the config
file, an alternative method is also shown in the code listing that follows

Code Listing 5.6: Establishing an RFCOMM connection
(The 0 refers to the rfcomm0 in the config file)
# rfcomm connect 0
Connected /dev/rfcomm0 to 00:0A:0B:0C:0D:0E on channel 1
Press CTRL-C for hangup

(If you did not edit /etc/bluetooth/rfcomm.conf)
# rfcomm connect 0 00:0A:0B:0C:0D:0E 1
Connected /dev/rfcomm0 to 00:0F:DE:69:50:24 on channel 1
Press CTRL-C for hangup

The first parameter after the connect command is the RFCOMM TTY device node
that will be used (usually 0). The second parameter is the MAC address of the
remote device. The third parameter is optional and specifies the channel to be
used. Please, note that in order to connect to a device, that device must be
listening for incoming connections. To do that, we have to explicitly tell it
to listen. We can cancel the communication at any moment by just hitting
CTRL+C.

Code Listing 5.7: Listening for incoming RFCOMM connections
# rfcomm listen 0 1
Waiting for connection on channel 1

In a similar way to the connect command, the listen command can receive two
parameters. The first one explicits the RFCOMM TTY device node (usually 0) that
will be used to accept a connection, while the second is the channel that will
be used.

Each time you call the rfcomm command, you can also specify the physical
device you want to use. Below you can see a small example specifiying the
physical device on the above two commands.

Code Listing 5.8: RFCOMM connections specifying physical device
# rfcomm -i hci0 listen 0 1
Waiting for connection on channel 1
(To listen to a determined device)
# rfcomm -i hci0 connect 0 00:0A:0B:0C:0D:0E 1
(To use a determined device when connecting to another one)

Setting up a Personal Area Network (PAN)

Note:
Please note that setting up a Personal Area Network is optional. This section
describes how to set up and connect to a Network Access Point, though setting
up a Group Ad-Hoc Network follows a similar way.

First of all, we need the bnep module loaded. And probably we want it
loaded each time the computer starts.

Code Listing 5.9: Loading the bnep module
# modprobe bnep
# echo “bnep” >> /etc/modules.autoload.d/kernel-2.6

We have to start the pand daemon in the host that will provide the NAP.
We’ll have to specify that we want to provide a NAP service and that this host
will be the master, thus the other hosts that connect to it, the slaves.
Another possible service is GN (Group ad-hoc Network).

Code Listing 5.10: Running the pand daemon
# pand –listen –role NAP –master –autozap

After doing that, we have a host listening, so the rest of hosts just have to
connect to that one.

Code Listing 5.11: Connecting to the Network Access Point
# pand –connect 00:0A:0B:0C:0D:0E –service NAP –autozap

If everything went fine, we can now configure the IP addresses of our hosts.

Code Listing 5.12: bnep IP address configuration
host0 # ifconfig bnep0 192.168.2.1
host1 # ifconfig bnep0 192.168.2.2

host0 # ifconfig bnep0
bnep0 Link encap:Ethernet HWaddr 00:0A:0B:0C:0D:0E
inet addr:192.168.2.1 Bcast:192.168.2.255 Mask:255.255.255.0
inet6 addr: fe80::210:60ff:fea3:cb41/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:5 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:208 (208.0 b) TX bytes:188 (188.0 b)

host1 # ifconfig bnep0
bnep0 Link encap:Ethernet HWaddr 00:01:02:03:04:05
inet addr:192.168.2.2 Bcast:192.168.2.255 Mask:255.255.255.0
inet6 addr: fe80::210:60ff:fea2:dd2a/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:5 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:208 (208.0 b) TX bytes:188 (188.0 b)

Finally, we can do a simple test to see that the network is working fine.

Code Listing 5.13: IP ping between bnep interfaces
host1 # ping 192.168.2.1
PING 192.168.2.1 (192.168.2.1) 56(84) bytes of data.
64 bytes from 192.168.2.1: icmp_seq=1 ttl=64 time=34.0 ms
64 bytes from 192.168.2.1: icmp_seq=2 ttl=64 time=37.3 ms

— 192.168.2.1 ping statistics —
2 packets transmitted, 2 received, 0% packet loss, time 1000ms
rtt min/avg/max/mdev = 34.045/35.690/37.336/1.656 ms

6. Desktop Applications for Bluetooth
Introduction

We have quite a few Bluetooth applications that run on the desktop and this
chapter has been divided into 3 parts, one each for Gnome, KDE and Miscellaneous
applications.

For Gnome

If you are a gnome user, you will most probably go with gnome-bluetooth.
It provides the most basic yet most used functionalities, as you can see below.

• gnome-bluetooth-manager: To manage Bluetooth remote devices.
• gnome-obex-send: To send files to other devices.
• gnome-obex-server: To receive files.

Code Listing 6.1: Installing gnome-bluetooth
# emerge gnome-bluetooth

This adds menu entries under Applications > System Tools from where you can
easily start up the manager or File sharing to transfer files between devices.

To transfer files (the easy way):

• From the Phone to the Computer – Send the file from the phone via Bluetooth
  and it will be picked up and saved to your /home always.

gnome-phone-manager is a nifty app that you can use to send and receive
messages to and from your phone, using only your system. You do not have to
touch your phone to read or send messages since all that happens through the
application. You are also notified of a new message on your screen if the option
is enabled under Preferences. Installation is a breeze as always.

Code Listing 6.2: Installing gnome-phone-manager
# emerge gnome-phone-manager

For KDE

KDE makes use of kdebluetooth and provides more utilities than its Gnome
counterpart as seen below.

• kbluetoothd: Bluetooth Meta Server.
• kbtsearch: Bluetooth device/service search utility.
• khciconfig: KDE Bluetooth Monitor.
• kioclient: KIO command line client.
• qobexclient: Swiss army knife for obex testing/development.
• kbtobexclient: A KDE Bluetooth Framework Application.
• kioobex_start
• kbtserialchat
• kbemusedsrv: KDE Bemused Server.
• kbtobexsrv: KDE OBEX Push Server for Bluetooth.
• kbluepin: A KDE KPart Application.
• auth-helper: A helper program for kbtobexsrv that sends an
  authentication request for a given ACL link.

Code Listing 6.3: Installing kdebluetooth
# emerge kdebluetooth

Other Interesting Applications

• app-mobilephone/obexftp: File transfer over OBEX for mobile phones
• app-mobilephone/bemused: Bemused is a system which allows you to
  control your music collection from your phone, using Bluetooth.
• app-pda/multisync: Multisync allows you to sync contacts, calendar
  entries and notes from your mobile phone with your computer, over a
  Bluetooth connection (amongst other things). It includes such features as
  backing up this information and restoring it later, and syncing with the
  Evolution e-mail client. You will need the irmc USE flag set to
  ensure that multisync has Bluetooth support.
• net-wireless/opd and net-wireless/ussp-push are command line
  tools (server and client) that can be used to send files to your mobile
  phone.

7. Acknowledgements

Special thanks to Marcel Holtmann
for his time and dedication to the Bluetooth development and for reviewing this
guide. And big thanks to Douglas Russell
for performing additional hardware tests and improving this guide.

The contents of this do*****ent are licensed under the Creative Commons -
Attribution / Share Alike license.

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