install-routes-linux

#!/bin/bash
# This script assumes a Linux system and something (like quagga) which will
# propagate as null routes the local static routes having a specific nexthop.
# It will sync these static routes with the ones in the list(s) by adding and
# removing local routes as needed.
# Set $DRY_RUN to only get a summary of the changes which would be applied.

source config.sh
test $LOGGING_ENABLE == true && echo "$(date '+%d/%m/%y %H:%m:%S') - Install Routes Linux Started" >> $LOGFILE

##############################################################################
if [ -t 0 ]; then VERBOSE=1; fi
if [ "$DRY_RUN" ]; then VERBOSE=1; fi

dprintf() {
  [ "$VERBOSE" ] || return 0
  printf "$*"
}

##############################################################################
list_routes() {
  local ip="$1"
  ip -o route list | awk "/ via $ip / {print \$1}"
}

##############################################################################
list_routes $BLACKHOLE_NEXTHOP | sort > tmp/routes.installed

for list in $LISTS; do
  test -e $LISTS_DIR/${list}-ip && grep '^[^#]' $LISTS_DIR/${list}-ip
done | sort | uniq > tmp/routes.new

comm -13 tmp/routes.installed tmp/routes.new > tmp/routes.added
comm -23 tmp/routes.installed tmp/routes.new > tmp/routes.removed

if [ -s tmp/routes.added ]; then
  dprintf "Routes to add:\n"
  while read ip; do
    dprintf "$ip\n"
    test $LOGGING_ENABLE == true && echo "$(date '+%d/%m/%y %H:%m:%S') - Added route for IP $ip" >> $LOGFILE
    [ "$DRY_RUN" ] && continue
    ip route add "$ip" via $BLACKHOLE_NEXTHOP 
    
    if [ $? != 0 ] ; then 
        test $LOGGING_ENABLE == true && echo "$(date '+%d/%m/%y %H:%m:%S') - ERROR: Cannot add a route for IP $ip" >> $LOGFILE
        echo "Cannot add a route for $ip!" >&2
    fi
  done < tmp/routes.added
fi

if [ -s tmp/routes.removed ]; then
  dprintf "Routes to remove:\n"
  while read ip; do
    dprintf "$ip\n"
    test $LOGGING_ENABLE == true && echo "$(date '+%d/%m/%y %H:%m:%S') - Removed route for IP $ip" >> $LOGFILE
    [ "$DRY_RUN" ] && continue
    ip route del "$ip" via $BLACKHOLE_NEXTHOP
    if [ $? != 0 ] ; then 
      test $LOGGING_ENABLE == true && echo "$(date '+%d/%m/%y %H:%m:%S') - ERROR: Cannot remove a route for IP $ip" >> $LOGFILE
      echo "Cannot remote the route for $ip!" >&2
    fi
  done < tmp/routes.removed
fi

rm -f tmp/routes.*

exit 0