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1 What is bluez

Bluez is the official Official Linux Bluetooth protocol stack and can be found at http://bluez.sourceforge.net/. Features can be found at http://bluez.sourceforge.net/features.html.

Bluez is already part of the official kernell 2.4 tree and if you have a recent distro your standard kernell will probably have it built in.

2 What can you do with bluez

For linux users bluez makes it possible to connect to and thus use bluetoothdevices. It becomes possible to use bluetooth usb-dongles, mobile phones with bluetooth, acces points and so on.

Thus you can connect two or more computers wireless, or phone your isp with your mobile bluetooth-enabled phone. You can synchronize your pim with your computer or phone. You can access your phone data and so on with your computer.

Q: More things?

3 How does bluez work

Bluez works by implementing the bluetooth standards for linux in the linux kernell and in bluetooth-device drivers and bluetooth layers. See below for a lot more detail

Q: is that correct?

 3.1 how does bluetooth work(the extreme short version:-))

Bluetooth is a standard for sending binary data over radio frequencies over a short distance. Bluetooth devices thus contain radio senders and receivers. In the end it sends 0's and 1's through the air in packets. The packets are send and received and processed in a layer-model of all kinds of protocols we can call lower-level or physical-level and data-link level protocols (OSI-model). Bluetooth has a number of profiles that define things you can do like synchronizing your pim data, making a personal area network and so on. This makes bluetooth more than just a radio-layer to build ethernet and ppp ip over.

Links to more information are below.

Ultimately these layers can be used by computers or other devices to send voice- or data, in the end all 0's and 1's, using higher-level protocols like ip and tcp/udp/icmp protocols.

3.11 OSI model

If we map the OSI-model to bluetooth and for comparison ethernet over utp (what you are probably using if you have a network) we get this picture:

OSI-layer ethernet bluetooth
        
Physical Layer utp-cable/nic/repeater radio-
waves/emitter/receiver Lmp/LC function: bit encoding and sending over medium

Data-Link Layer MAC and LLC/bridge L2CAP
 function: receiving frames upper layer and (dis)assemble them for
 physical layer. Adressing by for instance MAC-address. Also flow controle and (simple)error control (are all the frames received?) for single links between devices.

Network Layer IP/routers/packet-firewalls idem
 function adressing packets/routing and packet/message/circuit switching

Transport Layer tcp/udp/icmp tcp/udp/icmp
 Function: connections(tcp); repackaging segments/ error-control (checksums); end-to-end flow control.

Session layer Function: connection establishment/ error correction/negotiation of protocols/authentication Presentation layer function: data formatting Appliciation layer function: API to network

As you can see only the fiorst layers, like physical and data-link are really different from your usual tcp/ip over ethernet of telephony (ppp) communication.

Q: is this osi stuff helpful or annoying? Perhaps I should use ppp over telephone and not ethernet?

3.12 BT layers

Contents |1 What is bluez |2 What can you do with bluez |3 How does bluez work |3.1 how does bluetooth work |3.11 OSI model |3.12 BT layers |3.11 BT profiles |3.2 links to bluetooth stuff |3.3 how is this implemented in bluez |4 what do you need installed and what does it do |4.1 kernell stuff |4.2 programs and tools |5 how to install (what do i need to install anyway) |5.1 kernell stuff |5.2 programs and tools |6 what steps are needed to get things working |6.0 Get your bluetooth device up! |6.1 You have more computers you want in a bluetooth network: |Solution 1: make a bluetooth network with pan (bnep over l2cap) using rfcomm recipies: |Solution 2: attach two computers with ppp. ppp over rfcomm |Recipies: |6.2 You have an ipac or other mobile device and want to synchronize by using bluetooth. |Solution1: dund over pan |Resource: pan and dund over rfcomm |Recipies |6.3 You have a mobile phone and you want to dial into your isp |Solution: use pan and ppp over rfcomm |Recipies: |7. Reference guide: what does that word mean? |8. Leftovers from |9. Extra: Little guide to compile your kernel |10. Thanks to these guys you read this
The howto at http://eie555.eie.polyu.edu.hk/tut/tutorial/ says this:

Bluetooth Radio

The Bluetooth Radio (layer) is the lowest defined layer of the Bluetooth specification. It defines the requirements of the Bluetooth transceiver device operating in the 2.4GHz ISM band.

Bluetooth Baseband

The Baseband is the physical layer of the Bluetooth. It manages physical channels and links apart from other services like error correction, data whitening, hop selection and Bluetooth security. The Baseband layer lies on top of the Bluetooth radio layer in the bluetooth stack. The baseband protocol (..) carrying out link level routines like link connection and power control. The baseband also manages asynchronous and synchronous links, handles packets and does paging and inquiry to access and inquire Bluetooth devices in the area.

Link Manager Protocol (LMP)

The Link Manager carries out link setup, authentication, link configuration and other protocols. It discovers other remote LM´s and communicates with them via the Link Manager Protocol (LMP). To perform its service provider role, the LM uses the services of the underlying Link Controller (LC).

Host Controller Interface (HCI)

The HCI provides a command interface to the baseband controller and link manager, and access to hardware status and control registers. Essentially this interface provides a uniform method of accessing the Bluetooth baseband capabilities.The HCI exists across 3 sections, the Host - Transport Layer - Host Controller. Each of the sections has a different role to play in the HCI system.

Logical Link Control and Adaptation Protocol (L2CAP)

The Logical Link Control and Adaptation Layer Protocol (L2CAP) is layered over the Baseband Protocol and resides in the data link layer. L2CAP provides connection-oriented and connectionless data services to upper layer protocols with protocol multiplexing capability, segmentation and reassembly operation, and group abstractions. L2CAP permits higher level protocols and applications to transmit and receive L2CAP data packets up to 64 kilobytes in length. Two link types are supported for the Baseband layer : Synchronous Connection-Oriented (SCO) links and Asynchronous Connection-Less (ACL) links. SCO links support real-time voice traffic using reserved bandwidth. ACL links support best effort traffic. The L2CAP Specification is defined for only ACL links and no support for SCO links is planned.

RFCOMM Protocol. The RFCOMM protocol provides emulation of serial ports over the L2CAP protocol.

Service Discovery Protocol (SDP) The service discovery protocol (SDP) provides a means for applications to discover which services are available and to determine the characteristics of those available services.

3.11 BT profiles
Contents |1 What is bluez |2 What can you do with bluez |3 How does bluez work |3.1 how does bluetooth work |3.11 OSI model |3.12 BT layers |3.11 BT profiles |3.2 links to bluetooth stuff |3.3 how is this implemented in bluez |4 what do you need installed and what does it do |4.1 kernell stuff |4.2 programs and tools |5 how to install (what do i need to install anyway) |5.1 kernell stuff |5.2 programs and tools |6 what steps are needed to get things working |6.0 Get your bluetooth device up! |6.1 You have more computers you want in a bluetooth network: |Solution 1: make a bluetooth network with pan (bnep over l2cap) using rfcomm recipies: |Solution 2: attach two computers with ppp. ppp over rfcomm |Recipies: |6.2 You have an ipac or other mobile device and want to synchronize by using bluetooth. |Solution1: dund over pan |Resource: pan and dund over rfcomm |Recipies |6.3 You have a mobile phone and you want to dial into your isp |Solution: use pan and ppp over rfcomm |Recipies: |7. Reference guide: what does that word mean? |8. Leftovers from |9. Extra: Little guide to compile your kernel |10. Thanks to these guys you read this

The profiles have been developed in order to describe how implementations of user models are to be accomplished. The user models describe a number of user scenarios where Bluetooth performs the radio transmission. A profile can be described as a vertical slice through the protocol stack. Some Profiles are :
- GAP Profile The Generic Access Profile
- DNP or DUN (dial up)
- SPP (serial port) (rfcomm) - Lan Lan access profile
- Pan (BNEP) Personal area network
 - Sdap The Service Discovery Application Profile
- Ctp The Cordless Telephony Profile
 - IP Intercom profile
- HS Headset profile
 - FP Fax profile
- GOEP The Generic Object Exchange Profile (obex)
 - OPP Object push profile
 - FTP File transfer profile
 - SP Synchronisation profile (PIM-data)

 GAP Profile

The Generic Access Profile defines the generic procedures related to discovery of Bluetooth devices and link management aspects of connecting to Bluetooth devices. It is the core on which all other Profiles are based

 DNP or DUN Profile

The Dial-up Networking Profile defines the requirements that shall be used by devices (modems, cellular phones) implementing the usage model called ‘Internet Bridge'. The Gateway role is typically used in a mobile phone with Bluetooth dial-up networking capability and the Terminal role in PDA´s or laptops: thus dun has two roles: terminal and gateway. SDP BNEP TCS

 SPP Profile

The Serial Port Profile defines the requirements for Bluetooth devices necessary for setting up emulated serial cable connections using RFCOMM between two peer devices.

 LAP Profile

The LAN Access Profile defines how Bluetooth enabled devices can access the services of a LAN using PPP. Also, this profile shows how the same PPP mechanisms are used to form a network consisting of two Bluetooth-enabled devices.

 PAN profile or personal area network.

The Personal Area Networking (PAN) Bluetooth Network Encapsulation Specification describes the protocol to be used by the Bluetooth PAN profiles (BNEP or bluetooth network encapsulation protocol). This document defines a packet format for Bluetooth network encapsulation used to transport common networking protocols over the Bluetooth media. Bluetooth network encapsulation supports the same networking protocols that are supported by IEEE 802.3/Ethernet encapsulation. Packets from the supported networking protocols are contained in Bluetooth network encapsulation packets, which are transported directly over the Bluetooth L2CAP protocol. BNEP removes and replaces the Ethernet Header with the BNEP Header. The Ethernet Payload remains unchanged. Finally, both the BNEP Header and the Ethernet Payload is encapsulated by L2CAP and is sent over the Bluetooth media.

  SDAP

The Service Discovery Application Profile defines the features and procedures for an application in a Bluetooth device to discover services registered in other Bluetooth devices and retrieve any desired available information pertinent to these services.

CTP Profile

The Cordless Telephony Profile defines the features and procedures that are required for interoperability between different units active in the 3-in-1 phone use case. This profile also shows how the use case can be applied generally for wireless telephony in a residential or small office environment,

IP Profile

The Intercom Profile defines the requirements for Bluetooth devices necessary for the support of the intercom functionality within the 3-in-1 phone use case. This is also refereed to as the 'walkie-talkie' usage of Bluetooth

HS Profile

The Headset Profile defines the requirements that shall be used by devices implementing the usage model called ‘Ultimate Headset´.

FP Profile

The Fax Profile defines the requirements for Bluetooth devices necessary to support the Fax use case. This allows a Bluetooth cellular phone (or modem) to be used by a computer as a wireless fax modem to send/receive a fax message.

GOEP Profile (obex)

The Generic Object Exchange Profile lays the basis (defines the protocols and procedures) for Bluetooth devices necessary for the support of the object exchange usage models. The usage model can be the Synchronization , File Transfer, or Object Push model.

OPP Profile

The Object Push Profile defines the requirements for applications providing the object push usage model.Typical scenarios covered by this profile involve the pushing/pulling of data objects between Bluetooth devices

FTP Profile
The File Transfer Profile defines the requirements for applications providing the file transfer usage model.Typical scenarios involve a Bluetooth device browsing, transferring and manipulating objects on/with another Bluetooth device.

SP Profile
The Synchronization Profile defines the requirements for applications providing the synchronization usage model.Typical scenarios covered by this profile involving manual or automatic synchronization of PIM data when 2 Bluetooth devices come within range.

3.2 links to bluetooth stuff

The official site is http://www.bluetooth.com/. With many pdf-files
Core specifications are here:
http://www.bluetooth.com/pdf/Bluetooth_11_Specifications_Book.pdf

Tutorial/howto
The best explanation on bluetooth I know is here:
L2CAP: Logical Link Control and Adaptation Protocol
http://eie555.eie.polyu.edu.hk/tut/tutorial/l2cap.html
RFCOMM Protocol:
http://eie555.eie.polyu.edu.hk/tut/tutorial/rfcomm.html
Service Discovery Protocol (SDP) at
http://eie555.eie.polyu.edu.hk/tut/tutorial/sdp.html
Profiles at:
http://eie555.eie.polyu.edu.hk/tut/tutorial/profiles.html
PAN and BNEP at:
http://www.telematik.informatik.uni-
karlsruhe.de/lehre/WS0102/ag/BNEP.
pdf

Pan description at:
http://www.kjhole.com/Bluetooth/PDF/Bluetooth10.pdf

About Profiles at:
http://www.ericsson.com/bluetooth/files/profile_components.pdf

    Devices at: http://www.holtmann.org/linux/bluetooth/devices.html
Manymore links at : http://www.holtmann.org/linux/bluetooth/

HowTo set up common PAN scenarios with BlueZ's integrated PAN support http://bluez.sourceforge.net/contrib/HOWTO-PAN

3.3 how is this implemented in bluez

Bluez stack supports:
- General Access Profie
- Service Discovery Profile
- Serial Port Profile
- DialUp Networking Profile
- LAN Access Profile
- OBEX Object Push Profile
- OBEX File Transfer Profile
- PAN Profile

Bluez has a core package called bluez-kernel that includes all to set up the core of bluetooth. It takes care of making HCI-devices, the L2cap and LMP/LC protocols. It is already a part of the 2.4.x kernel. In kernel 2.4.18 you need to patch the kernel with the bluez-kernel package and compile the kernel (mandrake 9.0 for instance). In Mandrake 9.1, which uses kernel 2.4.21, you need not bother with patching your kernel: all code is already in. For other kernel's please see the website of Marcel Holtman which has the patches you need or see the bluez website for details. This how to only covers kernel 2.4.18 and 2.4.21 and beyond.

Included in the bluez-kernel code is HCI UART driver, HCI PCMCIA drivers RFCOMM protocol and some BNEP stuff. I think it also has sdp but I am not sure.

There are two more things you need for all bluetooth stuff. The bluetooth libraries (no idea why you need such things) and the bluez-utils. The bluez-utils are needed to bring the HCIx devices up for instance. You can also search for devices and bind serial ports and so on. It thus includes tools to use the kernel-code to make bluetooth connections and so on. It also included trouble shootings tools.

Separately is the Pan-package which includes LAN Access over PPP profile (dund) and has pand
 - PAN/BNEP client and server dund
 - LAN access client and server

Also separate is the SDP package with the sdp server I think to search and advertise bluetooth services (for instance a nokia 6310 has a dial-in service or modem it advertises by sdp.)

4 what do you need installed and what does it do

  4.1 kernell stuff

The best way is to install your own kernel with one of my Bluetooth patches. I prefer the 2.4.20-mh6, but you can also use the 2.4.19, but at the moment it only exists the -mh5 (I am working on the -mh6 for 2.4.19). And for example the -mh6 contains all previous patches for that kernel version, like the -ac ones.

You should not install the bluez-kernel-2.3 package, because it is deprecated and out of date. You will miss many bugfixes and features.

(my comment here: for kernel 2.4.18 you still need to as there is no other way)

As you are using the SuSE distribution, you can also try one of their new 2.4.20 kernels which includes an update the Bluetooth subsystem as it is now part of the 2.4.21-pre5. The upcoming SuSE 8.2 will use this kind of 2.4.20 by default.

Regards

Marcel

 4.2 programs and tools

5 how to install (what do i need to install anyway)

Whatever you want to do, you need kernel stuff for kernels below 2.4.21 (section 5.1), and always libs and utils (section 5.2):

5.1 kernell stuff

The best way is to install your own kernel with one of my Bluetooth patches. I prefer the 2.4.20-mh6, but you can also use the 2.4.19, but at the moment it only exists the -mh5 (I am working on the -mh6 for 2.4.19). And for example the -mh6 contains all previous patches for that kernel version, like the -ac ones. You should not install the bluez-kernel-2.3 package, because it is deprecated and out of date. You will miss many bugfixes and features.
(my comment here (Hans=Cees): for kernel 2.4.18 you still need to as there is no other way)
As you are using the SuSE distribution, you can also try one of their new 2.4.20 kernels which includes an update the Bluetooth subsystem as it is now part of the 2.4.21-pre5. The upcoming SuSE 8.2 will use this kind of 2.4.20 by default.

You need a compiled kernel without bluez in it. So do not compile in bluetooth and also definitly not the bluetooth module in the usb section! All below is the section short guide to compile a kernel. Download the code at http://bluez.sourceforge.net/download/download.html to for instance /home/myname

unpack the tar.gz like this:

tar -xzvf bluez-kernel-2.3.tar.gz

You will now have a directory called bluez-kernel-2.3. Go there

cd bluez-kernel-2.3

Follow the instructions in the README (cat README|more) probably it says to do this: do
./configure
and then
make make install

Then do

 ./create_dev

If that file is not there do either 1 or 2:

1. You can download the "./create_dev" script from:

http://cvs.sourceforge.net/cgi- bin/viewcvs.cgi/*checkout*/bluez/kernel/create_dev?rev=1.2

   (save it as "create_dev", and do "chmod +x create_dev" before
   running it)

2: type this with an enter after every line:

mknod /dev/vhci c 10 250
chmod 664 /dev/vhci

then type this:
C=0;
while [ $C -lt 256 ]; do
if [ ! -c /dev/rfcomm$C ]; then
mknod -m 666 /dev/rfcomm$C c 216 $C
fi
C=`expr $C + 1`
done

That is it. Watch out though that you type the almost last line with ` ` (below the ~) and not with ' ' or " "!!

5.2 programs and tools

1. I dowloaded and installed:

just put them all in one dir and do :
rpm -Uhv bl*.rpm

2. add in /etc/modules.conf:
alias net-pf-31 bluez
alias bt-proto-0 l2cap
alias bt-proto-2 sco
alias bt-proto-3 rfcomm
alias bt-proto-4 bnep
alias tty-ldisc-15 hci_uart

Now for the libs.
Download the libs: bluez-libs-2.2.tar.gz
tar -xzvf bluez-libs-2.2.tar.gz
cd bluez-libs-2.2
cat README|more
./configure
make
make install

Now the utils:
Downlaod bluez-utils-2.1.tar.gz
tar -xzvf bluez-utils-2.1.tar.gz
cd bluez-utils-2.1
cat README|more
./configure
make
make install

Note: with the utils I got an error that it could not find glib-config with mandrake 9. I missed the package libglib1.2-devel-1.2.10-6mdk.i586.rpm. Just for the case that you get the same error.

after that you install bluez-sdp-0.8 (version at 8/11/2002). Install bluez-sdp- 0.8, like above: download, untar;
./configure;make;make install.

Now you have installed what you need, let's get it working.

6 what steps are needed to get things working

6.0 Get your bluetooth device up!

To do bluetooth you need a bluetooth device. If you follow your log (tail -f /var/log/messages as root) you can see what happens if you plug your usb- dongle/serial-dongle/pcmcia-card in.

A warning!!!!
the bluetooth.o kernel module, which exists in the Linux kernel is a Bluetooth HCI USB (H2) to HCI UART (H4) converter for the Axis OpenBT stack. The BlueZ stack have native support for USB Bluetooth devices which is included in the hci_usb.o module. Since both modules serves the same devices, the hotplug stuff decides to load the bluetooth.o, because of the alphabetical order. You can solve this problem in many ways and the quickest one is to remove the bluetooth.o module from your harddisk.
Thus if something does not work, and you compiled your own pre-2.4.21 kernel, please search for bluetooth.o and delete it! 90% of all trouble stems form this mistake!!

hciconfig
wil show you if the device has been spotted.
hciconfig hci0 up
should show that the device is up. If so you are on your way.

hciattach <serial_device> <protocol> <speed> [flow]

to get the hci0 device working.

Just point /dev/modem to it with:
ln -s /dev/modem /dev/ttyS0

At least this is necessary on the iPaq 3870 that as a csr chip connected to a serial port, even with the latest bluez stuff (at 11/11/2002).

Only after this step a device hci0 appears when you do
 hciconfig hci0 up

Now it is needed before or after hciconfig hci0 up to tell hci the settings for hci0. Tell it with:

hcid -f /etc/bluetooth/hcid.conf
(I am told that run "/etc/init.d/bluetooth start" will also do the
trick)

You may guess that the success of what you do later will depend on that /etc/bluetooth/hcid.conf file. For using hci0 with rfcomm (the code that makes a bluetooth device look like a modem or serial device) to dial up at least, but perhaps also for other purposes that file reads:

# HCI daemon configuration file.
#
#
options {
        autoinit yes;
        security auto;
        pairing multi;
        pin_helper /etc/bluetooth/givepin;
}

device {
        name "LP_AH";
        class 0x100;
        pkt_type DH1,DM1,HV1;
        iscan enable; pscan enable;
        lm master;
        lp hold,sniff,park;
        auth enable;
        encrypt enable;
}

**********************************************************************
**** *******************************

You might want to change the name section. Also other things if you know what you are doing:-) See "hciconfig --help" to know more about this.

To make this work with the hcid.conf file above you need the /etc/bluetooth/givepin script. Here is mine:

##############givepin##########
#!/bin/sh
echo "PIN:123456"
################

Just open an editor and copy this into a file and save it as /etc/bluetooth/givepin Then do

chmod 710 /etc/bluetooth/givepin

Obviously your pin then is 123456. Use something different as a pin to be more secure! You need this pin when you connect to a bleutooth device for the first time to set up 'pairing' as it is called. For instance with my nokia 6310 I also put in 123456 the first time when I connected (after saying "yes" to let the connection in) and it answered that a pairing was set up.

When the files are set up and you did hcid -f /etc/bluetooth/hcid.conf you can find your bluetooth device by doing :

To search for services you can do:

Get the address of your phone by
hcitool scan.

For instace my phone is at bt-address:
00:03:EE:20:77:04

Do

so with my phone for example:

sdptool seach --service=DUN 00:03:EE:20:77:04