BTPAND(8) System Manager's Manual BTPAND(8)

btpand — Bluetooth PAN daemon

btpand [-i ifname] [-m mode] -a addr -d device {-s service | -S service [-p psm]}

btpand [-c path] [-i ifname] [-l limit] [-m mode] [-p psm] -d device {-s service | -S service}

The btpand daemon handles Bluetooth Personal Area Networking services in the system. It can operate in client mode as a Personal Area Networking User (PANU) or in server mode as Network Access Point (NAP), Group ad-hoc Network (GN) or PANU host. btpand connects to the system via a tap(4) virtual Ethernet device and forwards Ethernet packets to remote Bluetooth devices using the Bluetooth Network Encapsulation Protocol (BNEP).

The PANU client is the device that uses either the NAP or GN service, or can talk directly to a PANU host in a crossover cable fashion.

A GN host forwards Ethernet packets to each of the connected PAN users as needed but does not provide access to any additional networks.

The NAP service provides some of the features of an Ethernet bridge, with the NAP host forwarding Ethernet packets between each of the connected PAN users, and a different network media.

Note, the only differences between NAP and GN services as implemented by btpand are in the SDP service record. The bridging of packets by the NAP must be configured separately with brconfig(8).

The options are as follows:

address
In client mode, address of remote server. May be given as BDADDR or name, in which case btpand will attempt to resolve the address via the bt_gethostbyname(3) call.
path
In server mode, specify path to the sdpd(8) control socket. The default path is /var/run/sdp.
device
Restrict connections to the local device. May be given as BDADDR or name, in which case btpand will attempt to resolve the address via the bt_devaddr(3) call. btpand will set the tap(4) interface physical address to the BDADDR of the Bluetooth radio.
ifname
btpand uses the tap(4) driver to create a new network interface for use. Use this option to select a specific tap(4) device interface which must already be created.
limit
In server mode, limit the number of simultaneous connections. The default limit is 7 for NAP and GN servers, and 1 for a PANU server.
mode
Set L2CAP connection link mode. Supported modes are:

auth
require devices to be paired.
encrypt
auth, plus enable encryption.
secure
encryption, plus change of link key.
psm
Use an alternative L2CAP Protocol/Service Multiplexer (PSM) for server mode or client mode (when not using Service Discovery). The default PSM for BNEP is 15 (0x000f).
service
Name of service to provide or connect to, the following services are recognised:

GN
Group ad-hoc Network.
NAP
Network Access Point.
PANU
Personal Area Networking User.
service
As per -s except that btpand will not use SDP services for connection setup.

When providing networking services, the Bluetooth PAN profile says that the ‘Class of Device’ property of the bluetooth controller SHALL include Networking capability (set bit 0x020000). See btconfig(8) for details.

After btpand has set up the client or server connection and opened the tap(4) interface, it will create a pid file and detach.

/dev/tap
 
/etc/bluetooth/hosts
 
/var/run/sdp
 
/var/run/tap.pid
 

The btpand utility exits 0 on success, and >0 if an error occurs.

ifconfig tap1 create
btpand -a host -d ubt0 -s NAP -m encrypt -i tap1
dhcpcd -q -b tap1

Will create an encrypted connection to the NAP on host, and link that to the tap1 interface.

btpand -d ubt0 -s GN -m auth

Will create a Group Network requiring authentication to join and register the GN service with the local SDP server.

bluetooth(3), bluetooth(4), bridge(4), tap(4), brconfig(8), btconfig(8), dhcpcd(8), dhcpd(8), ifconfig(8), sdpd(8)

The "Personal Area Networking Profile" and "Bluetooth Network Encapsulation Protocol" specifications are available at http://www.bluetooth.com/

Iain Hibbert

There is no way to supply alternative values for the SDP record.

There is no way to set net type or multicast address filters.

btpand does not do any address routing except to directly connected unicast addresses. All other packets are multicast.

As btpand uses the BDADDR of the Bluetooth radio as the physical address of the tap, only one instance can be run per radio.

btpand can only provide a single service.

January 17, 2019 NetBSD 11.0