filter.sh

#!/bin/bash
# filter.sh: Generates a filter list for a router based on an input AS-SET or ASN.

# Copyright 2009-2011 Matthew Walster

# Distributed under the terms of the GNU General Public Licence

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# Define a usage statement
usage()
{
	echo "$0: A filterlist generator"
	echo "Usage: $0 [OPTS] AS-SET"
	echo "    -t | --type [ juniper | cisco | brocade | force10 | redback | quagga | iosxr ]"
	echo "    -n | --name [ Filter Name ]"
	echo "    -h | --host [ WHOIS server ]"
	echo "         --ipv4"
	echo "         --ipv6"
}

# Initialise some variables, to make it safe to use
FILTERNAME="filter"
SEQNUM=10
INC=5
IP_LIST=""
WHOISSERVER="whois.radb.net"
IP_VERSION="4"
CRAZY="0"

# Parse the command line options
while [[ $1 = -* ]]; do
	case "$1" in
		-t|--type)
			TYPE="$2"
			shift 2
			;;
		-n|--name)
			FILTERNAME="$2"
			shift 2
			;;
		-h|--host)
			WHOISSERVER="$2"
			shift 2
			;;
		-s|--seq)
			SEQNUM="$2"
			INC="$3"
			shift 3
			;;
		--ipv4)
			IP_VERSION="4"
			shift
			;;
		--ipv6)
			IP_VERSION="6"
			shift
			;;
		--crazy)
			CRAZY="1"
			shift
			;;
		--help)
			usage
			exit 1
			;;
		*)
			echo "Error: Unknown option: $1" >&2
			usage
			exit 1
			;;
	esac
done

# If no arguments, then just show the usage statement
if [[ $# -lt 1 ]]
	then usage
	exit 1
fi

# Do we have an AS-SET or an ASN?
IS_SET=$(whois -h whois.radb.net $1 | grep -i ^as-set: | awk -F: '{print $1}')

# If we've got an AS-SET, use the handy !i and ,1 commands on RADB
if [[ "as-set" == "$IS_SET" ]]
then
	AS_LIST=$(whois -h whois.radb.net \!i$1,1 | sed '/^\[/d' | sed 2\!d)
else
	AS_LIST=$1
fi

if [[ $CRAZY == 0 ]]
then
	# Find out which prefixes are contained within that AS number
	for i in $AS_LIST
	do
		case "$IP_VERSION" in
			4)
				IP_LIST_UNSORTED+=$(whois -h $WHOISSERVER -- "-i origin $i" | grep ^route: | cut -f 2 -d: | sed 's/ //g')
				;;
			6)
				IP_LIST_UNSORTED+=$(whois -h $WHOISSERVER -- "-i origin $i" | grep ^route6: | cut -f 2- -d: | sed 's/ //g')
				;;
		esac
		IP_LIST_UNSORTED+=$(echo " ")
	done
elif [[ $CRAZY == 1 ]]
then
	tmpfile=$(mktemp /tmp/filter.XXXXXXXX) || exit 1
	case "$IP_VERSION" in
		4)
			curl ftp://ftp.ripe.net/ripe/dbase/split/ripe.db.route.gz \
				| gunzip -dc \
				| grep -e '^route:' -e '^origin:' \
				| sed -e 'N;s/\n/ /' -re 's/route:\s+//g;s/origin:\s+//g' \
				>$tmpfile
			GREP_OPTS=$(sed -re 's/AS/ -e AS/g' <<<$AS_LIST)
			IP_LIST_UNSORTED=$(grep $GREP_OPTS $tmpfile | cut -f1 -d" ")
			;;
		6)
			curl ftp://ftp.ripe.net/ripe/dbase/split/ripe.db.route6.gz \
				| gunzip -dc \
				| grep -e '^route:' -e '^origin:' \
				| sed -e 'N;s/\n/ /' -re 's/route6:\s+//g;s/origin:\s+//g' \
				>$tmpfile
			GREP_OPTS=$(sed -re 's/AS/ -e AS/g' <<<$AS_LIST)
			IP_LIST_UNSORTED=$(grep $GREP_OPTS $tmpfile | cut -f1 -d" ")
			;;
	esac

	rm $tmpfile
fi

# Remove duplicate routes
IP_LIST=$(printf "%s\n" $IP_LIST_UNSORTED | sort -t . -k 1,1n -k 2,2n -k 3,3n -k 4,4n | uniq)

# If we're on Force10 or Redback (which uses similar syntax), create the prefix-list
if [[ "$TYPE" == "force10" || "$TYPE" == "redback" ]]
then
	echo "ip prefix-list $FILTERNAME"
elif [[ "$TYPE" == "iosxr" ]]
then
	echo "prefix-set $FILTERNAME"
fi

FIRST=1
# Format the output nicely
for i in $IP_LIST
do
	case "$TYPE" in
		juniper)
			echo "set policy-options policy-statement $FILTERNAME term auto-generated from route-filter $i exact"
			;;
		cisco)
			if [[ "$IP_VERSION" == "4" ]]
			then
				echo "ip prefix-list $FILTERNAME seq $SEQNUM permit $i"
				let SEQNUM=SEQNUM+$INC
			elif [[ "$IP_VERSION" == "6" ]]
			then
				echo "ipv6 prefix-list $FILTERNAME seq $SEQNUM permit $i"
				let SEQNUM=SEQNUM+$INC
			fi
			;;
		brocade)
			echo "ip prefix-list $FILTERNAME permit $i"
			;;
		force10)
			echo " seq $SEQNUM permit $i"
			let SEQNUM=SEQNUM+$INC
			;;
		redback)
			echo " seq $SEQNUM permit $i"
			let SEQNUM=SEQNUM+$INC
			;;
		iosxr)
			if [[ $FIRST -eq 0 ]];
			then
				echo ","
			fi

			echo -n "$i"
			;;
		quagga)
			if [[ "$IP_VERSION" == "4" ]]
			then
				echo "ip prefix-list $FILTERNAME seq $SEQNUM permit $i"
				let SEQNUM=SEQNUM+$INC
			elif [[ "$IP_VERSION" == "6" ]]
			then
				echo "ipv6 prefix-list $FILTERNAME seq $SEQNUM permit $i"
				let SEQNUM=SEQNUM+$INC
			fi
			;;
		*)
			echo $i
			;;
	esac

	FIRST=0
done

if [[ "$TYPE" == "iosxr" ]]
then
	echo ""
	echo "end-set"
	echo "!"
fi

# Tell the Juniper router to accept those prefixes
if [[ "$TYPE" == "juniper" ]]
then
	echo "set policy-options policy-statement $FILTERNAME term auto-generated then accept"
fi