#!/bin/bash
# netperf - Analyze the netstat running performance log, identifying
#    important results and trends.

setglobal log = '"/Users/taylor/.netstatlog'"     # change for your config
setglobal stats = ""/tmp/netperf.stats.$Pid""
setglobal awktmp = ""/tmp/netperf.awk.$Pid""

trap "$[which rm] -f $awktmp $stats" 0

if test ! -r $log  {
  echo "Error: can't read netstat log file $log" > !2
  exit 1
}

# First, report the basic statistics of the latest entry in the log file...

eval $[tail -1 $log]    # all values turn into shell variables

setglobal rep = $[scriptbc -p 3 $re/$snt'*'100]
setglobal repn = $[scriptbc -p 4 $re/$snt'*'10000 | cut -d. -f1]
setglobal repn = "$shExpr(' $repn / 100 ')"
setglobal retop = $[scriptbc -p 3 $reto/$snt'*'100]; 
setglobal retopn = $[scriptbc -p 4 $reto/$snt'*'10000 | cut -d. -f1]
setglobal retopn = "$shExpr(' $retopn / 100 ')"
setglobal dupp = $[scriptbc -p 3 $dup/$rec'*'100]; 
setglobal duppn = $[scriptbc -p 4 $dup/$rec'*'10000 | cut -d. -f1]
setglobal duppn = "$shExpr(' $duppn / 100 ')"
setglobal oop = $[scriptbc -p 3 $oo/$rec'*'100]; 
setglobal oopn = $[scriptbc -p 4 $oo/$rec'*'10000 | cut -d. -f1]
setglobal oopn = "$shExpr(' $oopn / 100 ')"

echo "Netstat is currently reporting the following:"

/bin/echo -n "  $snt packets sent, with $re retransmits ($rep%) "
echo "and $reto retransmit timeouts ($retop%)"
/bin/echo -n "  $rec packets received, with $dup dupes ($dupp%)"
echo " and $oo out of order ($oop%)"
echo "   $creq total connection requests, of which $cacc were accepted"
echo ""

## Now let's see if there are any important problems to flag

if test $repn -ge 5  {
  echo "*** Warning: Retransmits of >= 5% indicates a problem "
  echo "(gateway or router flooded?)"
}
if test $retopn  -ge 5  {
  echo "*** Warning: Transmit timeouts of >= 5% indicates a problem "
  echo "(gateway or router flooded?)"
}
if test $duppn -ge 5  {
  echo "*** Warning: Duplicate receives of >= 5% indicates a problem "
  echo "(probably on the other end)"
}
if test $oopn -ge 5  {
  echo "*** Warning: Out of orders of >= 5% indicates a problem "
  echo "(busy network or router/gateway flood)"
}

# Now let's look at some historical trends...

echo "Analyzing trends...."

while read logline {
    eval $logline
    setglobal rep2 = $[scriptbc -p 4 $re / $snt '*' 10000 | cut -d. -f1]
    setglobal retop2 = $[scriptbc -p 4 $reto / $snt '*' 10000 | cut -d. -f1]
    setglobal dupp2 = $[scriptbc -p 4 $dup / $rec '*' 10000 | cut -d. -f1]
    setglobal oop2 = $[scriptbc -p 4 $oo / $rec '*' 10000 | cut -d. -f1]
    echo "$rep2 $retop2 $dupp2 $oop2" >> $stats
  } < $log

echo ""

# Now calculate some statistics, and compare them to the current values.

cat << ''' > $awktmp
    { rep += $1; retop += $2; dupp += $3; oop += $4 }
END { rep /= 100; retop /= 100; dupp /= 100; oop /= 100;
      print "reps="int(rep/NR) ";retops=" int(retop/NR) \
         ";dupps=" int(dupp/NR) ";oops="int(oop/NR) }
'''
> $awktmp
    { rep += $1; retop += $2; dupp += $3; oop += $4 }
END { rep /= 100; retop /= 100; dupp /= 100; oop /= 100;
      print "reps="int(rep/NR) ";retops=" int(retop/NR) \
         ";dupps=" int(dupp/NR) ";oops="int(oop/NR) }
EOF

eval $[awk -f $awktmp < $stats]

if test $repn -gt $reps  {
  echo "*** Warning: Retransmit rate is currently higher than average."
  echo "    (average is $reps% and current is $repn%)"
}
if test $retopn -gt $retops  {
  echo "*** Warning: Transmit timeouts are currently higher than average."
  echo "    (average is $retops% and current is $retopn%)"
}
if test $duppn -gt $dupps  {
  echo "*** Warning: Duplicate receives are currently higher than average."
  echo "    (average is $dupps% and current is $duppn%)"
}
if test $oopn -gt $oops  {
  echo "*** Warning: Out of orders are currently higher than average."
  echo "    (average is $oops% and current is $oopn%)"
}
echo '('Analyzed $[wc -l < $stats] netstat log entries for calculations')'
exit 0