#!/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-0.3.1
#
# 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 and Hugo Meiland <hugo@meiland.nl>
#

IFACE=wi0
NETWORK=wleiden.net

if [ ! "x$1" -eq "x" ]; then
	IFACE=$1
fi

if [ ! "x$2" -eq "x" ]; then
	NETWORK=$2
fi

# check current connection
check_conn()
{
	LOSS=`ping -c 5 -q $ROUTER|grep loss|cut -f 7 -d " "|cut -f 1 -d %` 				
	if [ $LOSS -lt 4 ]; then 	
		echo "your connection is fine, bailing out..."
		exit 0	
	fi
}

# default IFACE mode

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

# update available APs

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

	if [ -z "$AS" ]; then
		echo "No accespoints found..." 
		exit 0
	fi
}

# get available NETWORK APs

get_AAP()
{
	I=0
	SNB=0
	
	while [ $I -lt $AS ]; do		
		
		AP=`wicontrol -i $IFACE -l |grep -A 5 ap.$I. |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
				
			 	ifconfig $IFACE ssid $SSID	
				killall dhclient 
				dhclient -1 $IFACE 
				set -- `netstat -rn |grep default` 
				ROUTER=$2				
				LOSS=`ping -c 5 -q $ROUTER|grep loss|cut -f 7 -d " "|cut -f 1 -d %` 				
				if [ $LOSS -lt 4 ]; then 	
					SNB=$SN	
					SSIDB=$SSID
				fi
			fi	
		fi

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

# set ssid with best SN

set_SSID()
{
	if [ -z "$SSIDB" ]; then
		echo "No accespoints from" $NETWORK "found..." 	
		exit 0
	fi
	
	ifconfig $IFACE ssid $SSIDB

	echo "Connected to" $SSIDB ", enjoy..."
}

# putting everything together

check_conn
default_IFACE_mode
update_AAP
get_AAP 
set_SSID