#!/bin/bash

# ppp or ./optus-dongle 
# usage: sudo ./ppp [start|status|stop|log]

interface=ppp0
logfile=/tmp/optus-dongle.log
serialdevice=/dev/ttyUSB0
baudrate=460800
phonenumber=*99#


error() {
    echo "ERROR executing $1"
    exit 1
}


execute() {
    echo "executing: $1"
    bash -c "$1" || error "$1"
    return 0
}


############################################################

if [ $(whoami) != root ]
then
  echo "run script as root"
  exit 1
fi

if [ -z "$(sudo which pppd)" ]
  echo "need to install point-to-point protocol daemon program (pppd)" 
  exit 2
fi

case "$1" in
start)	# this sets up and runs pppd
  
  echo -e "\n\n\n$(/bin/date)">>$logfile
  echo "########### OPTUS dongle session started ############">>$logfile
  
  read -p "attach optus dongle and then press ENTER < "
  
  # make sure that the kernel has switched the CDROM mode to USBserial
  # by checking that it has created the serial USB device /dev/ttyUSB0
  echo -n "waiting for $serialdevice to be created ... "
  serial=notcreated
  while [ $serial == notcreated ]
  do
    [ $(/bin/ls -l 2>/dev/null $serialdevice|wc -l) -gt 0 ] && serial=created
  done
  echo "OK"
  /bin/ls -l 2>/dev/null $serialdevice|tee -a $logfile
  
  # put the nameservers that we discovered Optus uses into /etc/resolv.conf
  echo "establishing primary and secondary nameservers"
  cat > /tmp/resolv.conf <<"EOF"
nameserver 198.142.0.51
nameserver 61.88.88.88
EOF
  sudo mv /tmp/resolv.conf /etc/resolv.conf
  cat /etc/resolv.conf|tee -a $logfile
  
  # before we connect, make sure this ppp0 interface is protected
  if ! -x /usr/local/bin/iptables.init ]
  then
    echo "need to start firewall for ppp0 interface"
    exit 3
  fi
  read -p "press ENTER to start firewall < "
  sudo /usr/local/bin/iptables.init ppp0|tee -a $logfile|less
  
  read -p "press ENTER to start pppd session < "
  
    echo -e "\a"
    read -p "enter PIN (leave empty if no PIN) < " PIN
    if [ ! -z "$PIN" ]
    then
        echo -e "AT+CPIN=${PIN}\r">$serialdevice
        sleep 1
    fi

  echo "using serial device $serialdevice"|tee -a $logfile
  echo "using baud rate $baudrate"|tee -a $logfile
  echo "using phone number $phonenumber"|tee -a $logfile
  
  # run the normal pppd, and note the spaces between '' and ATZ (etc)
  sudo /usr/sbin/pppd $serialdevice $baudrate noauth debug connect "/usr/sbin/chat -v ''  ATZ  OK  ATDT${phonenumber}  CONNECT  '\d\c'"
  
  # wait until the /sbin/ifconfig command shows that ppp0 has been created
  echo -n "waiting for interface $interface to be created ... "
  ppp=pending
  while [ $ppp == pending ]
  do
    [ $(/sbin/ifconfig 2>/dev/null $interface|grep -v error|wc -l) -gt 0 ] && ppp=ready
    sleep 1
  done
  echo "OK"
  
  # wait until the /sbin/ifconfig command shows a valid inet address is assigned
  echo -n "waiting for IP address ... "
  ipaddress=pending
  while [ $ipaddress == pending ]
  do
    [ $(/sbin/ifconfig $interface|grep 'inet addr'|wc -l) -gt 0 ] && ipaddress=ready 
    sleep 1
  done
  echo "OK"
  /sbin/ifconfig $interface|grep 'inet addr'|tr -s ' '
  sleep 3
  /sbin/ifconfig $interface|tee -a $logfile
  
  # if there are any other interfaces, make sure this is the default one
  sudo /sbin/route add default ppp0
  sudo /sbin/route -n
  
  echo "now may access internet: browser, w3m, apt-get, etc."
  echo "run 'ppp log' to see /var/log/ppp.log"
  echo "run 'ppp stop' to finish this ppp session"
  ;;

status) # show the state of the ppp0 interface
  /sbin/ifconfig $interface
  ;;

stop) 	# get traffic on the serial ppp0 interface
  /sbin/ifconfig $interface|grep 'RX bytes'|tr -s ' '|tee -a $logfile
  echo "########### ppp session finished ############"|tee -a $logfile
  sudo kill $(pidof pppd)
  echo "when solid blue light goes out, you may disconnect dongle"
  echo "run 'ppp log' to examine $logfile"
  ;;

log) 	# show the details of the pppd negotiation first
  if [ ! -e /var/log/ppp.log ]
  then
    echo "you have not yet set up ppp logging"
    echo "refer to http://axion.physics.ubc.ca/ppp-linux.html"
  else
    sudo tail -100 /var/log/ppp.log|less
  fi
  # show the results of running this ppp session next
    less $logfile
  ;;
*)
  echo "usage: sudo ./ppp [start|status|stop|log]"
  exit 0
  ;;
esac

exit 0