#!/bin/sh
#
# connect to the closest WiFi hotspot
#
# primarily designed for use on the WirelessLeiden network, this tool will check whether your connection
# is stable enough, otherwise it will start looking for a better accesspoint...
# 
# version-0.3.3
#
# 2004-02-02: fixed get_AAP bug (roland)
# 2004-02-01: fixed recursive ip lookup (hugo)
# 2004-01-31: fixed $ROUTER (hugo)
# 2004-01-25: added pre-connection check (hugo)
# 2004-01-19: re-write of script (roland)
# 2004-01-05: added ip-checks around ssid check (hugo)
# 2004-01-02: one-liner ssid check (roland)
#
# Copyright (c), 2004 Roland van Laar <the_mip_rvl@myrealbox.com> and Hugo Meiland <hugo@meiland.nl>
#

IFACE=wi1
NETWORK=wleiden.net
LOGFILE=/var/logs/follow.log
TEST_PINGS=5
SIGNAL_FILE=/tmp/rc.follow.tmp

PATH="/sbin:/usr/sbin:/bin:/usr/bin"
export PATH

if [ $# != 2 -a $# != 0 ]; then
	echo Syntax: $0 \[\<iface\> \<network\>\]
	exit 255
fi

if [ $# = 2 ]; then
	IFACE=$1
	NETWORK=$2
fi

# check current connection
check_conn()
{
	echo "checking connection to $ROUTER ..." >> $LOGFILE

	set `ping -c ${TEST_PINGS} -q -n $ROUTER| grep loss`

	# Check if at least one packet is received.
	if [ $4 -gt 0 ]; then
		echo "your connection is fine, bailing out..." >> $LOGFILE 
		exit 0	
	fi

	echo "connection check failed..." >> $LOGFILE
}

# default IFACE mode

default_IFACE_mode()
{
	ifconfig $IFACE down 
	ifconfig $IFACE up
	ifconfig $IFACE ssid "" 

	return 0
}

# update available APs

update_AAP()
{
	AS=`wicontrol -i $IFACE -L | grep station | cut -f 1 -d " "`

	# removed - as we never seem to clean this up
	# .. when using -at least put in a 'trap ... { rm -f ..}'	
	# temp=`basename $0`
	# TMPFILE=`mktemp -t ${temp}.XXXXXX`
	# /usr/sbin/wicontrol -i $IFACE -l > $TMPFILE	

	if [ -z "$AS" ]; then
		echo "No accespoints found..." >> $LOGFILE 
		exit 1
	fi

	return 0
}

# get available NETWORK APs

get_AAP()
{
	I=0
	SNB=0
	
	while [ $I -lt $AS ]; do		

		AP=`grep -A 5 ap.$I. ${SIGNAL_FILE} | /grep -A 3 $NETWORK`
		
		if [ -n "$AP" ]; then 	
			set -- $AP
			SSID=$4
			SN=${17}		

		 	# get the SSID with the best SN	
			if [ $SN -gt $SNB ]; then
				# ip connect check
				echo "connecting to $SSID" >> $LOGFILE
			 	/sbin/ifconfig $IFACE ssid $SSID	
				/usr/bin/killall dhclient 
				/sbin/dhclient -1 $IFACE 
				set -- `/usr/bin/netstat -rn | /usr/bin/grep default` 
				ROUTER=$2				
				set `/sbin/ping -c ${TEST_PINGS} -q -n $ROUTER| /usr/bin/grep loss`
				if [ $4 -gt 0 ]; then
					SNB=$SN	
					SSIDB=$SSID
				fi
			fi	
		fi

		I=$(($I + 1))
	done

	return 0
}

# set ssid with best SN

set_SSID()
{
	if [ -z "$SSIDB" ]; then
		echo "No accespoints from" $NETWORK "found..." >> $LOGFILE	
		exit 1
	fi
	
	ifconfig $IFACE ssid $SSIDB || exit 1

	echo "Connected to" $SSIDB", enjoy..." >> $LOGFILE

	return 0
}

# putting everything together

# ?? what creates rc.folow.tmp ??
#	
if [ ! -e ${SIGNAL_FILE} ]; then
	echo no ${SIGNAL_FILE}
	exit 1
fi

set -- `netstat -rn | grep default` 
ROUTER=$2				

if [ x$ROUTER != "x" ]; then
	check_conn
fi

default_IFACE_mode 
update_AAP 
get_AAP || exit $?
set_SSID || exit $?

grep -q ${LOGFILE} /etc/newsyslog || echo WARNING - no logfile rotation

exit 0