From: eLinux.org
Bluetooth Network
This page has information about setting up a Bluetooth Personal Area Network (PAN) with BlueZ. Having a Bluetooth network is helpful for providing network access to low power embedded devices.
Contents
- 1 Background
- 2 Limitations
- 3 Requirements
- 4 BlueZ Configuration
- 5 Bridge Configuration
- 6 Setup DHCP
- 7 Setup Network
- 8 Client Device
Background
Information on piconets can be found on Wikipedia Basic information on BlueZ PAN support can be found here: 1(http://bluez.sourceforge.net/contrib/HOWTO-PAN)
Limitations
A PAN network is limited to 7 clients and provides substantially less bandwidth (~700Kbit/s) than other WiFi networks.
Requirements
To setup a home piconet, you'll need:
- A Bluetooth device, such as a USB dongle, preferably Class 1 for range purposes.
- A kernel that supports the Bluez stack including BNEP.
- bluez-utils (testing with 3.36).
- Kernel ethernet bridging support.
- bridge-utils (tested with 1.4).
These instructions are based on a Debian/Sid system, but the setup should be similar for other distributions.
BlueZ Configuration
Setup /etc/bluetooth/hcid.conf
hcid.conf(5) Your piconet server should advertise itself appropriately. Modify the class parameter within the device section so that the host presents itself as a network access point device offering network service:
# Local device class
class 0x020300;
Change your piconet server to prefer master role on incoming connections:
lm master;
Make your piconet server permanently discoverable:
discovto 0;
Daemon Configuration
pand(1) Setup the command line options for the pand daemon. Within Debian, this is done through the file /etc/default/bluetooth. The command lines for the pand daemon should be:
--listen --role NAP -u /etc/bluetooth/pan/dev-up -o /etc/bluetooth/pan/dev-down
End Result (When host is connected)
ifconfig bnep0
bnep0 Link encap:Ethernet HWaddr 00:11:f6:05:79:95
inet6 addr: fe80::211:f6ff:fe05:7995/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:23661 errors:0 dropped:0 overruns:0 frame:0
TX packets:29381 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:2976646 (2.8 MiB) TX bytes:27249215 (25.9 MiB)
hcitool con
Connections:
> ACL 00:1B:DC:0F:A8:AE handle 8 state 1 lm MASTER
Bridge Configuration
The kernel only provides an Ethernet device when at least one PAN client has connected. This means that there will be no associated device when no devices are connected. This can be very inconvenient when providing services such as DHCP. By utilizing Ethernet Bridging, a permanent pan0 device can be created.
Setup /etc/network/interfaces
bridge-utils-interfaces(5) On Debian systems, network interfaces are configured through this file. An example configuration would be:
auto pan0
iface pan0 inet static
address 10.1.0.1
netmask 255.255.255.0
broadcast 10.1.0.255
bridge_ports none
bridge_fd 0
bridge_stp off
Alternatively, the pan0 interface can be configured manually:
brctl addbr pan0
brctl setfd pan0 0
brctl stp pan0 off
ifconfig pan0 10.1.0.1 netmask 255.255.255.0
Setup /etc/bluetooth/pan/dev-{up|down}
The dev up/down files add and remove the bnep0 device from the pan0 bridge interface as the first device enters the network, and as the last device leaves the network.
/etc/bluetooth/pan/dev-up
#!/bin/sh
ifconfig $1 up
brctl addif pan0 $1
/etc/bluetooth/pan/dev-down
#!/bin/sh
brctl delif pan0 $1
ifconfig $1 down
End Result (When host is connected)
brctl show
bridge name bridge id STP enabled interfaces
pan0 8000.0011f6057995 no bnep0
ifconfig pan0
pan0 Link encap:Ethernet HWaddr 00:11:f6:05:79:95
inet addr:10.1.0.1 Bcast:10.1.0.255 Mask:255.255.255.0
inet6 addr: fe80::200:ff:fe00:0/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:30706 errors:0 dropped:0 overruns:0 frame:0
TX packets:40037 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:3681538 (3.5 MiB) TX bytes:34573855 (32.9 MiB)
Setup DHCP
Unless avahi zeroconf will be used to assign address, a DHCP server will be required.
Setup /etc/dhcpd.conf
Basic configuration:
option domain-name-servers <dns1>,<dns2>,<dns3>;
default-lease-time 864000;
max-lease-time 864000;
subnet 10.1.0.0 netmask 255.255.255.0 {
option domain-name "blue";
range 10.1.0.100 10.1.0.200;
option routers 10.1.0.1;
}
Daemon Configuration
Setup the command line options for the dhcpd daemon. Within Debian, this is done through the file /etc/default/dhcp. Tho command lines for the dhcpd daemon should be:
pan0
Setup Network
If your piconet server is not the machine you intend to access your piconet devices from and/or your piconet devices need to access hosts other than your piconet server, routing and/or NAT will need to be configured
Shorewall
Adding your piconet to an existing Shorewall configuration is by far the easiest method.
params
BLUE_IF=pan0
interfaces
#ZONE INTERFACE BROADCAST OPTIONS
blue $BLUE_IF detect tcpflags,dhcp,detectnets,nosmurfs
zones
#ZONE TYPE OPTIONS IN OUT
# OPTIONS OPTIONS
blue ipv4
policy
Allow piconet to access Internet:
#SOURCE DEST POLICY LOG LIMIT:BURST
# LEVEL
blue net ACCEPT
A rule like the following would allow the local network to access the piconet:
#SOURCE DEST POLICY LOG LIMIT:BURST
#
loc all ACCEPT
The last line of the policy file should of course contain an all/all DROP rule.
masq
Allow local network to access piconet masquerading as piconet server:
#INTERFACE SUBNET ADDRESS PROTO PORT(S) IPSEC
$BLUE_IF $LOC_IF
Masquerade piconet network access to Internet
#INTERFACE SUBNET ADDRESS PROTO PORT(S) IPSEC
$NET_IF $BLUE_IF
rules
Not allowing your open piconet to do things like Spam and/or access your Cable modem is probably a good thing.
#ACTION SOURCE DEST PROTO DEST SOURCE ORIGINAL RATE USER/
# PORT PORT(S) DEST LIMIT GROUP
SMTP/REJECT blue net
DROP blue net:10.0.0.0/8,192.168.0.0/16,172.16.0.0/12
Netfilter
A very basic Netfilter setup, assuming that eth1 connects to the Internet, and eth0 connects to the local network.
# Enable masquerading access to the Internet (rule may already exists)
iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE
# Enable masquerading access to the piconet from the local net
iptables -t nat -A POSTROUTING -i eth0 -o pan0 -j MASQUERADE
# Enable routing (may already exist)
echo 1 > /proc/sys/net/ipv4/ip_forward
Network Manager 0.7
Network Manager provides connection sharing functionality. From the "Edit Connections" dialog, select "Add". Name the connection bnep0 and enter the Bluetooth device's MAC address into the Wired tab. Select "Shared to other computers" on the "IPv4 Settings" tab.
Client Device
Embedded devices should execute the command:
pand --connect <bdaddr of piconet server> --persist -u ifup -o ifdown
Upon boot, alternatively, the following command can be used:
pand --search --persist -u ifup -o ifdown
/etc/network/interfaces file
This step applies to Debian and Debian like (Angstrom/OE) distributions. Modification will be required for other distributions:
# Bluetooth networking
allow-hotplug bnep0
iface bnep0 inet dhcp
End result
ifconfig bnep0
bnep0 Link encap:Ethernet HWaddr 00:1B:DC:0F:A8:AE
inet addr:10.1.0.100 Bcast:10.1.0.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:29272 errors:0 dropped:0 overruns:0 frame:0
TX packets:23598 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:27242050 (25.9 MiB) TX bytes:2964918 (2.8 MiB)
route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
10.1.0.0 0.0.0.0 255.255.255.0 U 0 0 0 bnep0
0.0.0.0 10.1.0.1 0.0.0.0 UG 0 0 0 bnep0
hcitool con
Connections:
< ACL 00:11:F6:05:79:95 handle 42 state 1 lm SLAVE
