#!/usr/bin/perl
# GPL V2 or greater
# Used to control the 4 led's on ubiquti for device aiming.
# Written by Conrad Lara KG6JEI



sub aimmode_printusage{
  print "USAGE:\n";
  print "$0 SSID\n";
  die;
}


# SSID NAME
if ( $ARGV[0] ) {
  $SSIDName= lc $ARGV[0];
}
else
{
  $SSIDName= lc "AREDN-20-v3";
}

#dbm values for each RSSI trigger level
$RSSI_4=-65;
$RSSI_3=-73;
$RSSI_2=-80;
$RSSI_1=-94;

# LED Set Wrappe
sub SetLED {
  ($fh, $state ) = @_ ;
  print $fh $state ;
  binmode($fh);
}


# Reset LED's to baseline
sub init_led_triggers {

  open ( LINK4_trigger,'>/sys/class/leds/ubnt:green:link4/trigger');
  open ( LINK3_trigger,'>/sys/class/leds/ubnt:green:link3/trigger');
  open ( LINK2_trigger,'>/sys/class/leds/ubnt:orange:link2/tigger');
  open ( LINK1_trigger,'>/sys/class/leds/ubnt:red:link1/trigger');

  print LINK4_trigger "none";
  print LINK3_trigger "none";
  print LINK2_trigger "none";
  print LINK1_trigger "none";

  close ( LINK4_trigger);
  close ( LINK3_trigger);
  close ( LINK2_trigger);
  close ( LINK1_trigger);

}

sub aimmode_start {

  # Prep the system
  system('/etc/init.d/linkled stop');
  system('/etc/init.d/olsrd stop');
  system('/sbin/ifdown wifi');
  system('/sbin/ifdown wifi_mon');
  system('/usr/sbin/iw phy phy0 interface add mon0 type monitor');
  system('/usr/sbin/iw dev mon0 set channel 1');
  system('/sbin/ifconfig mon0 up');
  #Open up the files we will need to run with
  # Run tcpdump in buffered (-l) mode so each line returns with a newline
  open ( $TCPDUMP,"/usr/sbin/tcpdump -l -i mon0 \"link[0] == 0x80\" |");
  open ( $LINK4_led,'>/sys/class/leds/ubnt:green:link4/brightness');
  open ( $LINK3_led,'>/sys/class/leds/ubnt:green:link3/brightness');
  open ( $LINK2_led,'>/sys/class/leds/ubnt:orange:link2/brightness');
  open ( $LINK1_led,'>/sys/class/leds/ubnt:red:link1/brightness');


}
sub aimmode_shutdown {

  #Turn off all LED's except LINk4

  SetLED ($LINK4_led, 1);
  SetLED ($LINK3_led, 0);
  SetLED ($LINK2_led, 0);
  SetLED ($LINK1_led, 0);

  close ($TCPDUMP);
  close ($LINK4_led);
  close ($LINK3_led);
  close ($LINK2_led);
  close ($LINK1_led);
  # Brining up wifi is a bit more complicated than just ifconfig up so we let `ifup` handle it ... takes a bit to finish so sleep 10s
  system('ifup wifi');
  system('ifup wifi_mon');
  print "Please wait while we restart the services";
  sleep 10;
  system('/etc/init.d/olsrd start');
  system('/etc/init.d/linkled start');
}

init_led_triggers();

$SIG{INT} = sub { aimmode_shutdown(); exit; };


aimmode_start();

# Main while loop
while ( <$TCPDUMP> )
{
  next unless /.* ([\d\-]+)dB.*Beacon \((.*)\)/;
  next unless lc $2 eq $SSIDName ;

  #Average the last value and this values in order to tame sudden spikes
  $s=int(($1+$lastvalue)/2);
  print "$s \n";

  if ($s >= $RSSI_4 ) {
    SetLED ($LINK4_led, 1);
  }
  else
  {
    SetLED ($LINK4_led, 0);
  }

  if ($s >= $RSSI_3 ) {
    SetLED ($LINK3_led, 1);
  }
  else
  {
    SetLED ($LINK3_led, 0);
  }

  if ($s >= $RSSI_2 ) {
    SetLED ($LINK2_led, 1);
  }
  else
  {
    SetLED ($LINK2_led, 0);
  }

  if ($s >= $RSSI_1 ) {
    SetLED ($LINK1_led, 1);
  }
  else
  {
    SetLED ($LINK1_led, 0);
  }


  $lastvalue=$s;

}

# Normally the SIG{INT} handler will be done before here
# But in case the TCPDUMP dies out we want to reset the system
aimmode_shutdown();