DebConf10/Wireless

Using the debconf wireless

The SSID is debconf. Ask around for the password, or use the 'Columbia Wireless' network (which is open) to get it off someone on IRC.

Documentation for the OpenWRT setup at DebConf10

This page describes the accesspoint configuration for DebConf10. We're using the Backfire version of OpenWRT.

The accesspoints will be bridging to provide WPA encrypted wireless on debconf . On the b+g network we'll use the channels 1, 3, 9 and 11. This is not ideal, but the wireless space at Columbia is fairly congested and channel 6 is used all over campus for the unencrypted 'Columbia Wireless' access points. We avoid interference as much as possible by turning down the power on the APs, and it will very likely also help for people to turn down the power on their laptops to something like 10dBm.

Hardware list

• 15x Buffalo WHR-G54 (currently only 11, but the others are around somewhere...)

Buffalo Configurations

We're using the standard images from Backfire 10.03 here. On the buffalo the needed file is the broadcom 47xx .trx file, which uses the open source b43 drivers.

/etc/config/network

config 'switch' 'eth0'
	option 'enable' '1'

config 'switch_vlan' 'eth0_0'
	option 'device' 'eth0'
	option 'vlan' '0'
	option 'ports' '1 2 3 4 5'

config 'switch_vlan' 'eth0_1'
	option 'device' 'eth0'
	option 'vlan' '1'
	option 'ports' '0 5'

config 'interface' 'loopback'
	option 'ifname' 'lo'
	option 'proto' 'static'
	option 'ipaddr' '127.0.0.1'
	option 'netmask' '255.0.0.0'

config 'interface' 'lan'
	option 'type' 'bridge'
	option 'ifname' 'eth0.0'
	option 'proto' 'dhcp'
	# option 'proto' 'static'
	# option 'ipaddr' '192.168.1.1'
	# option 'netmask' '255.255.255.0'

config 'interface' 'wan'
	option 'ifname' 'eth0.1'
	option 'proto' 'static'
	option 'ipaddr' '192.168.144.1'
	option 'netmask' '255.255.255.0'
	option 'dns' '128.59.62.10'  # Columbia DNS resolver

/etc/config/wireless

config 'wifi-device' 'radio0'
	option 'type' 'mac80211'
	option 'macaddr' '00:0D:0B:83:XX:XX'
	option 'hwmode' '11g'
	option 'disabled' '0'
	option 'channel' '1'
	option 'txpower' '6'    # adjusted when managing the AP later
	option 'distance' '20'  # adjusted when managing the AP later

config 'wifi-iface'
	option 'device' 'radio0'
	option 'network' 'lan'
	option 'mode' 'ap'
	option 'ssid' 'debconf'
	option 'encryption' 'mixed-psk+tkip+ccmp'
	option 'key' 'v3ry 5ecret'

Flashing

Buffalo

#!/bin/sh

IP=${1:-"192.168.11.1"}

ME="`echo ${IP} | cut -f1-3 -d.`.254"
sudo ip addr add ${ME}/24 dev eth0

echo "Unplug power, press button on top and replug power"
echo "Release the button when the upload starts after about 3 seconds"
CONFIG=config
#atftp --trace --option "mode octet" -p -l openwrt-brcm-2.4-squashfs.trx ${IP}

CONFIG=config26
atftp --trace --option "mode octet" -p -l openwrt-brcm47xx-squashfs.trx ${IP}

sudo ip addr del ${ME}/24 dev eth0

sudo ip addr add 192.168.1.254/24 dev eth0

echo "Waiting for flashing"
sleep 50
echo "Waiting for reboot"
sleep 50

echo "Telnet to assign passwd"
telnet 192.168.1.1

## Not needed for now, since we're using DHCP
# echo "Edit to assign IP address"
# gvim -f ${CONFIG}/network

echo "Edit to assign wireless channel"
gvim -f ${CONFIG}/wireless

echo "Edit to assign Hostname"
gvim -f ${CONFIG}/system

echo "Push ssh authorized_keys to device"
scp ~/.ssh/id_rsa.pub root@192.168.1.1:/etc/dropbear/authorized_keys

echo "Push configuration to device"
scp ${CONFIG}/* root@192.168.1.1:/etc/config

scp kmod-ipv6_2.6.32.10-1_brcm47xx.ipk root@192.168.1.1:
ssh root@192.168.1.1 opkg install kmod-ipv6_2.6.32.10-1_brcm47xx.ipk

Issues

Rogue AP detection

There appears to be Rogue AP detection (and some kind of countermeasures - talk to Andrew McMillan if you know about this stuff and want to hear our conjectures) which is stopping us from using the APs on the normal campus network. Fortunately the CS department has made available a network which we can use, and which does not cause the countermeasures to be triggered. Unfortunately this is only a /24 so we need to create NAT gateways etc. etc.

Issues Log

Add your issue here, including the MAC address of the AP you saw the issue with, the date & time, and any other useful information you can think of. Then tell karora on IRC your own wireless MAC address.

See also

• DebConf10/LAN

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