/etc/bluetooth/hcid.conf - Configuration file for the hcid Bluetooth HCI daemon

/etc/bluetooth/hcid.conf contains all the options needed by the Bluetooth Host Controller Interface daemon.

It consists of sections and parameters. A section begins with the name of the section followed by optional specifiers and the parameters inside curly brackets. Sections contain parameters of the form:

name value1, value2 ... ;

Any character after a hash ('#') character is ignored until newline. Whitespace is also ignored.

The valid section names for hcid.conf are, at the moment:

options

contains generic options for hcid and the pairing policy.

device

contains lower-level options for the hci devices connected to the computer.

The following parameters may be present in an option section:

autoinit yes|no

Automatically initialize newly connected devices. The default is no.

pairing none|multi|once

none means that pairing is disabled. multi allows pairing with already paired devices. once allows pairing once and denies successive attempts. The default hcid configuration is shipped with multi enabled

pin_helper "file"

The path to the PIN helper application. The default is "/bin/bluepin". The following output is expected from the PIN helper:

PIN:12345678

Or, when no PIN is available:

ERR

dbus_pin_helper

Declaring this parameter enables the D-BUS message bus system for PIN requests.

security none|auto|user

none means the security manager is disabled. auto uses local PIN, by default from /etc/bluetooth/pin, for incoming connections. user always asks the user for a PIN.

Parameters within a device section with no specifier, the default device section, will be applied to all devices and device sections where these are unspecified. The following optional device specifiers are supported:

nn:nn:nn:nn:nn:nn

Parameters specified within this section will be applied to the device with this device bluetooth address. All other parameters are applied from the default section.

hcin

Parameters specified within this section will be applied to the device with this device interface, unless that device is matched by a device address section. All other parameters are applied from the default section.

Note: Most of the options supported in the device section are described to some extent in the bluetooth specification version 1.2 Vol2, Part E section 6. Please refer to it for technical details.

The following parameters may be present in a device section:

name "name"

The device name. %d inserts the device id. %h inserts the host name.

auth enable|disable

Enables or disables authentication between local and remote devices when they connect.

Authentication is done following a challenge-response mechanism described in the Bluetooth Specification 1.2 volume 2 part C section 4.2, and uses the link key generated during pairing as the shared secret.

Activating this option sets the local device into Bluetooth security mode 3.

encrypt enable|disable

Enable or disable link encryption. Should be set to enable in most cases, unless one of the devices does not support encryption for some reason.

Encryption can only occur on authenticated connections, as a shared secret key is necessary for encryption to work. The detailed encryption mechanism is described in the bluetooth specification as mentioned above.

class 0xSSDDdd (three bytes)

The Bluetooth Device Class is described in the Bluetooth Specification section 1.2 ("Assigned Numbers - Bluetooth Baseband").

The default shipped with hcid is 0x000100 which simply stands for "Computer".

The Bluetooth device class is a high-level description of the bluetooth device, composed of three bytes: the "Major Service Class" (byte "SS" above), the "Major Device Class" (byte "DD" above) and the "Minor Device Class" (byte "dd" above). These classes describe the high-level capabilities of the device, such as "Networking Device", "Computer", etc. This information is often used by clients who are looking for a certain type of service around them.

Where it becomes tricky is that another type of mechanism for service discovery exists: "SDP", as in "Service Discovery Protocol".

In practice, most Bluetooth clients scan their surroundings in two successive steps: they first look for all bluetooth devices around them and find out their "class". You can do this on Linux with the hcitool scan command. Then, they use SDP in order to check if a device in a given class offers the type of service that they want.

This means that the hcid.conf "class" parameter needs to be set up properly if particular services are running on the host, such as "PAN", or "OBEX Obect Push", etc: in general a device looking for a service such as "Network Access Point" will only scan for this service on devices containing "Networking" in their major service class.

Major service class byte allocation (from LSB to MSB):

Bit 1: Positioning (Location identification)

Bit 2: Networking (LAN, Ad hoc, ...)

Bit 3: Rendering (Printing, Speaker, ...)

Bit 4: Capturing (Scanner, Microphone, ...)

Bit 5: Object Transfer (v-Inbox, v-Folder, ...)

Bit 6: Audio (Speaker, Microphone, Headset service, ...)

Bit 7: Telephony (Cordless telephony, Modem, Headset service, ...)

Bit 8: Information (WEB-server, WAP-server, ...)

Example: class 0x02hhhh : the device offers networking service

Major device class allocation:

0x00: Miscellaneous

0x01: Computer (desktop,notebook, PDA, organizers, .... )

0x02: Phone (cellular, cordless, payphone, modem, ...)

0x03: LAN /Network Access point

0x04: Audio/Video (headset,speaker,stereo, video display, vcr.....

0x05: Peripheral (mouse, joystick, keyboards, ..... )

0x06: Imaging (printing, scanner, camera, display, ...)

Other values are not defined (refer to the Bluetooth specification for more details

Minor device class allocation: the meaning of this byte depends on the major class allocation, please refer to the Bluetooth specifications for more details).

Example: if PAND runs on your server, you need to set up at least class 0x020100, which stands for "Service Class: Networking" and "Device Class: Computer, Uncategorized".

iscan enable|disable

pscan enable|disable

Bluetooth devices discover and connect to each other through the use of two special Bluetooth channels, the Inquiry and Page channels (described in the Bluetooth Spec Volume 1, Part A, Section 3.3.3, page 35). These two options enable the channels on the bluetooth device.

iscan enable: makes the bluetooth device "discoverable" by enabling it to answer "inquiries" from other nearby bluetooth devices.

pscan enable: makes the bluetooth device "connectable to" by enabling the use of the "page scan" channel.

lm none|accept,master

none means no specific policy. accept means always accept incoming connections. master means become master on incoming connections and deny role switch on outgoing connections.

lp none|rswitch,hold,sniff,park

none means no specific policy. rswitch means allow role switch. hold means allow hold mode. sniff means allow sniff mode. park means allow park mode. Several options can be combined.

This option determines the various operational modes that are allowed for this device when it participates to a piconet. Normally hold and sniff should be enabled for standard operations.

hold: this mode is related to synchronous communications (SCO voice channel for example).

sniff: when in this mode, a device is only present on the piconet during determined slots of time, allowing it to do other things when it is "absent", for example to scan for other bluetooth devices.

park: this is a mode where the device is put on standby on the piconet, for power-saving purposes for example.

rswitch: this is a mode that enables role-switch (master <-> slave) between two devices in a piconet. It is not clear whether this needs to be enabled in order to make the "lm master" setting work properly or not.

pkt_type DH1,DM1,HV1, etc.

This fairly obscure option determines the packet types that the bluetooth device will send or accept. This is a very low-level option that should probably not be changed for normal use. You do not need to specify defaults.

You can check the Bluetooth specification version 1.2 Volume 2, Part B section 6 for more details about this.

/etc/bluetooth/hcid.conf

Default location of the global configuration file.

/etc/bluetooth/pin

Default location of local PIN file, used for incoming connections in security mode auto. The file contains the PIN code terminated by newline.

This manual page was written by Edouard Lafargue, Fredrik Noring and Maxim Krasnyansky.