#!/bin/bash
# Bandwidth usage script
# Ted Percival <ted@midg3t.net> 2007
# bash is required to get 64-bit arithmetic
#
# Use this however you like. http://creativecommons.org/licenses/publicdomain/
#
# This script is publicly accessible, currently from
# http://lazypants.org/~ted/bwusag

set -e
# Config options
IFACE=eth0
CACHEDIR=$HOME/.cache
# These two hold the interface byte counter values
CACHE_RX_FILE=$CACHEDIR/bwusag-rx
CACHE_TX_FILE=$CACHEDIR/bwusag-tx
# These two hold the calculated actual usage for use when the machine reboots
CACHE_RXUSAGE_FILE=$CACHEDIR/bwusag-usage-rx
CACHE_TXUSAGE_FILE=$CACHEDIR/bwusag-usage-tx
TZ=Australia/Brisbane
LANG=en_AU.UTF-8
# End config options

# Make sure we can find ifconfig
PATH=/sbin:$PATH

export LANG TZ

CUR_RX=`ifconfig $IFACE | grep '^ *RX bytes' | cut -d: -f2 | cut -d' ' -f1`
CUR_TX=`ifconfig $IFACE | grep ' TX bytes:' | cut -d: -f3 | cut -d' ' -f1`

if [ "$1" = "newmonth" ]; then
	echo $CUR_RX > $CACHE_RX_FILE
	echo $CUR_TX > $CACHE_TX_FILE
fi

START_RX=`cat $CACHE_RX_FILE`
START_TX=`cat $CACHE_TX_FILE`

if test $(( $CUR_RX - $START_RX )) -lt 0; then
	# Machine has been rebooted, adjust the counters to compensate
	START_RX=-`cat $CACHE_RXUSAGE_FILE`
	START_TX=-`cat $CACHE_TXUSAGE_FILE`
	# Update stored values
	echo $START_RX > $CACHE_RX_FILE
	echo $START_TX > $CACHE_TX_FILE
fi

# Update the usage byte counter
echo $(( $CUR_RX - $START_RX )) > $CACHE_RXUSAGE_FILE
echo $(( $CUR_TX - $START_TX )) > $CACHE_TXUSAGE_FILE

USED_RX_MB=$((( $CUR_RX - $START_RX ) / 1024 / 1024 ))
USED_TX_MB=$((( $CUR_TX - $START_TX ) / 1024 / 1024 ))
USED_RX_GB=$(( $USED_RX_MB / 1024 ))
USED_TX_GB=$(( $USED_TX_MB / 1024 ))

TOTAL_USAGE_MB=$(( $USED_RX_MB + $USED_TX_MB ))
TOTAL_USAGE_GB=$(( $TOTAL_USAGE_MB / 1024 ))

echo "$TOTAL_USAGE_GB GiB"
echo "$TOTAL_USAGE_MB MiB"
echo
echo "Up: $USED_TX_GB GiB, Down: $USED_RX_GB GiB"
echo "Up: $USED_TX_MB MiB, Down: $USED_RX_MB MiB"
echo
#echo "Updated: `date -R`"
uptime

exit 0