Network topology plotting with bash and graphviz.

I was looking for a way to map the routing between me and a bunch of hosts in Linux but couldn’t find a program I liked. The nice thing about Linux though is the ease that you can put something together with other tools. Here’s a simple bash script that parses tcptraceroute output and graphs it using graphviz, enjoy.

#!/bin/bash

if [ -z $1 ]; then
echo “Specify host file”
exit
fi

if [ -z $2 ]; then
echo “Specify output file”
exit
fi

if [ ! -f “/usr/bin/dot” ]; then
echo “Dot not found, install graphviz first”
exit
fi

if [ ! -f “/usr/bin/tcptraceroute” ]; then
echo “Tcptraceroute not found, go install it”
exit
fi

rm $2.png &>/dev/null
rm $2.dot &>/dev/null

echo “strict graph $2 {” >> $2.dot

for hosts in `cat $1`
do
echo Tracing to: $hosts
prev=LOCAL
mloop=1
lastvalid=LOCAL
tcptraceroute -n -q 1 -w 1 -m 50 $hosts 2>/dev/null >> tempfile.txt
while read curdst; do
hopip=`echo $curdst | grep -o -E ‘([0-9]{1,3}\.){3}[0-9]{1,3}’`
if [ -z $hopip ]; then
echo “\”$prev\” — \”Prev $lastvalid Hop $mloop\”;” >> $2.dot
prev=”Prev $lastvalid Hop $mloop”
else
final=`echo $curdst | grep -o -E ‘(\[open\]|\[closed\])’`
if [ “$final” == “[open]” -o “$final” == “[closed]” ]; then
hopname=`nslookup $hopip | grep -o -E ‘=.+’ | grep -o -E ‘[^= ].+’`
echo “\”$prev\” — \”$hopip\n$hopname\”;” >> $2.dot
else
echo “\”$prev\” — \”$hopip\”;” >> $2.dot
fi
lastvalid=$hopip
prev=$hopip
fi
let “mloop=$mloop+1”
done < tempfile.txt rm tempfile.txt done echo “}” >> $2.dot

dot -Tpng -o $2.png $2.dot &>/dev/null

~ by s3c on 2011/04/01.