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|
#!/bin/sh
# wifichoice.sh by Stefan Tomanek (stefan@pico.ruhr.de)
# http://localhost.ruhr.de/~stefan/interfaces/
#
# Wifichoice selects the proper configuration profile for your WLAN
# interface by scanning for the right environment.
# To achieve this, it can either scan for the correct access point
# or ESSID, or try to associate with the configured network.
#
# Configuration is done in a central way via /etc/network/interfaces:
#
# mapping wlan0
# script /usr/local/sbin/ifichoice.sh
# map default: none
# map timeout: 2
#
# Timeout is the number of seconds the script waits after a test
# association for the device to settle, and default is the profile
# that shoud be loaded is if no known surrounding is detected.
#
# The test parameters are defined in the profiles themselves:
#
# iface home inet dhcp
# wireless yes
# wireless_mode managed
# wireless_key open 1234567890ABCDEF1234567890
# wireless_essid mywifinet
# wifichoice ap 00:12:34:56:78:9A
#
# Since your access point does not not broadcast its ESSID,
# and/or your card does not support "iwlist scan", wifichoice tries to
# associate with the network, using the supplied config, and then checks
# whether the network is managed by the right access point.
#
# If you can identify the network by its broadcasted ESSID or AP, you can
# also try to scan for it. Just add a line like this to your profile:
#
# wifichoice scan essid mywifinet
#
# Wifichoice then invokes a scan for neighbouring access points, and
# identifies those that serve the requested ESSID. It is also possible
# to scan for a specific access point address, this is useful if the AP
# does not transmit its ESSID:
#
# wifichoice scan ap 00:12:34:56:78:9A
# Which physical interface do we operate on?
IFACE=$1
# How long do we wait for the interface to settle?
TIMEOUT=2
# What is the default profile?
DEFAULT=""
DEBUG=0
# Paths to files
ENI=/etc/network/interfaces
IWCONFIG=/sbin/iwconfig
IFCONFIG=/sbin/ifconfig
IWLIST=/sbin/iwlist
IWGETID=/sbin/iwgetid
readConfig() {
while read L <&0; do
OPTION="$(echo $L | cut -d: -f1)"
VALUE="$(echo $L | cut -d ' ' -f2)"
if [ "$OPTION" = "default" ]; then
DEFAULT=$VALUE
elif [ "$OPTION" = "timeout" ]; then
TIMEOUT=$VALUE
elif [ "$OPTION" = "debug" ]; then
DEBUG=$VALUE
fi
done
debugMSG "Debug output is enabled"
debugMSG "Timout is $TIMEOUT seconds"
debugMSG "Default profile is $DEFAULT"
}
reset() {
IF="$1"
CONF="mode managed enc off ap auto essid auto"
$IWCONFIG $IF $CONF
$IFCONFIG $IF down
}
config() {
IF="$1"
reset $IF
CONF="$2"
debugMSG "Trying wireless configuration: $CONF";
$IWCONFIG $IF $CONF
$IFCONFIG $IF up
sleep $TIMEOUT
}
checkAP() {
IF="$1"
AP="$2"
[ "$($IWGETID $IF -ra)" = "$AP" ]
}
scanESSID() {
IF="$1"
ESSID="$2"
FOUND=0
# certain PC-Cards need this
$IFCONFIG $IF up
$IWLIST $IF scan | egrep -q '^[[:space:]]*ESSID:"'$ESSID'"$' && FOUND=1
$IFCONFIG $IF down
[ $FOUND -eq 1 ]
}
scanAP() {
IF="$1"
AP="$2"
FOUND=0
$IFCONFIG $IF up
$IWLIST $IF scan | egrep -q '^[[:space:]]*Cell [[:digit:]]+ - Address: '$AP'$' && FOUND=1
$IFCONFIG $IF down
[ $FOUND -eq 1 ]
}
debugMSG() {
if [ $DEBUG -eq 1 ]; then echo "$*" >&2 ; fi
}
checkProfile() {
FOUND=0
if [ "$METHOD" = "ap" ]; then
debugMSG "Trying to associate with $PROFILE"
AP="$(echo $TEST | cut -d ' ' -f 2)"
config $IFACE "$CONFIG"
checkAP $IFACE $AP && FOUND=1
elif [ "$METHOD" = "scan" ]; then
debugMSG "Scanning for $PROFILE"
# What are we scanning for?
# We support essid and ap
FOR="$(echo $TEST | cut -d ' ' -f 2)"
VAL="$(echo $TEST | cut -d ' ' -f 3)"
if [ "$FOR" = "essid" ]; then
debugMSG "Scanning for essid $VAL"
scanESSID $IFACE $VAL && FOUND=1
elif [ "$FOR" = "ap" ]; then
debugMSG "Scanning for access point $VAL"
scanAP $IFACE $VAL && FOUND=1
fi
fi
if [ $FOUND -eq 1 ]; then
debugMSG "Success!"
echo $PROFILE >&3
fi
[ $FOUND -eq 1 ]
}
# Kill STDOUT
exec 3>&1 1>/dev/null
readConfig
PROFILE=""
CONFIG=""
FOUND=0
TEST=""
METHOD=""
sed 's/^[[:space:]]*//; s/#.*$//g' $ENI | while read LINE; do
if echo $LINE | egrep -q '^iface [[:alnum:]]+'; then
# new profile started, check for past profile
if [ "$PROFILE" ] && [ "$TEST" ]; then
checkProfile $PROFILE $TEST $METHOD && break;
fi
# reset vars
PROFILE="$(echo $LINE | cut -d " " -f 2)"
CONFIG=""
TEST=""
METHOD=""
elif echo $LINE | egrep -q '^wireless(_|-)([[:alnum:]])+'; then
CMD="$(echo $LINE | sed 's/^wireless\(_\|-\)//')"
CONFIG="$CONFIG$CMD "
elif echo $LINE | egrep -q '^wifichoice'; then
TEST="$(echo $LINE | cut -d ' ' -f 2-)"
METHOD="$(echo $TEST | cut -d ' ' -f 1)"
reset $IFACE
fi
done
reset $IFACE
|
