#/bin/bash

# Script  to select a random server 
# from a list of servers (via a round robin DNS)
# and rsync a bunch of files from that server 
# 
# Takes a list of DNS records, 
# and a list of source folders,
# expands each DNS record to a list of IP Addresses
# then picks a random IP to rsync the given folder 
# from (retrying a different server if rsync fails), 
# before moving on to the next DNS record.
#
# Used to pull  various 0-day spam/malware signatures
# for clamav. This caches the files locally, 
# and thus enables the internal-only mail servers
# to pull these files from a local repo
#
# By Cris Haddad

#####################
# SETTINGS          #
#####################

# An array of  DNS records
# which each resolve to a list of 
# rsync mirrors, 'round robin' style
# NB Array index starts at ZERO

RR_MIRRORS[0]="rsync.sanesecurity.net"
#RR_MIRRORS[1]="clamav.securiteinfo.com"
#RR_MIRRORS[2]="www.malwarepatrol.net"

# Source folder on each remote server 
# make sure the array index matches 
# the server above!
SOURCE_DIR[0]="sanesecurity"
#SOURCE_DIR[1]="securesite"
#SOURCE_DIR[2]="malwarepatrol"

# Destination folder on local host 
# again make sure the array index matches 
# the server above!
DESTINATION_DIR[0]="/ftp/pub/misc/malwaresigs/sanesecurity"
#DESTINATION_DIR[1]="/ftp/pub/misc/malwaresigs/securesite"
#DESTINATION_DIR[2]="/ftp/pub/misc/malwaresigs/malwarepatrol"

# Text file with list of files to sync 
SYNC_FILE_LIST="/ftp/mirror/mirror.malwaresigs.conf"

#number of attempts to rsync 
MAX_RETRIES="6"

# Uncomment to enable debug output
#DEBUG="TRUE"




#################################
## do not edit below this point #
#################################


# a quick sanity check  to make sure we have arrays
# of matching lengths 
# we subtract 1 at thispoint so that we can use
# this number later  to iterate
# through the array 

last_mirror=`expr ${#RR_MIRRORS[@]} - 1`
last_dir=`expr ${#SOURCE_DIR[@]} - 1`
if [ "$last_mirror" -ne "$last_dir" ]; then 
	echo "ERROR: configured SOURCE_DIR count does not match RR_MIRRORS count"; 
	exit 2; 
fi

#now iterate through the arrays
for i in `seq 0 $last_mirror`
do
	current_mirrorset=${RR_MIRRORS[$i]}
	current_sourcedir=${SOURCE_DIR[$i]}
	current_destdir=${DESTINATION_DIR[$i]}
	if [ -n "$DEBUG" ]; then { echo "INFO: current mirror set is $current_mirrorset"; } fi  
	if [ -n "$DEBUG" ];  then { echo "INFO: current source dir is $current_sourcedir";} fi

	#expand the round robin DNS to a list of IPs
	source_servers=`dig +ignore +short $current_mirrorset`
	
	#load the list of IPs into an array
	read -a server_array <<<$source_servers
	
	if [ -n "$DEBUG" ]; then { echo "INFO: Servers are:";  for i in ${server_array[@]}; do echo $i; done }; fi 
	if [ -n "$DEBUG" ]; then { echo "DEBUG: Array length is: ${#server_array[@]}"; }; fi
	
	#array addresses start at zero, obviously
	last_entry=`expr ${#server_array[@]} - 1`
	if [ -n "$DEBUG" ]; then { echo "DEBUG: last entry is therefore : $last_entry"; }; fi
	if [ ! $last_entry -gt 0 ] ; then 
		echo "ERROR: No mirrors found. This may be a temporary failure, but if it persists then there may be a problem. "
		exit 2
	fi
	
	for j in `seq 1 $MAX_RETRIES`
	do
	 	#pick a random  server
		random_selection=`shuf -i 0-$last_entry -n 1`
		if [ -n "$DEBUG" ]; then { echo "DEBUG: Randomly selected server number: $random_selection"; }; fi
	
		random_server=${server_array[$random_selection]}
		if [ -n "$DEBUG" ]; then { echo "INFO: Randomly selected server IP address: $random_server"; }; fi
	
		#let's get the DNS name, just for fun 
		random_server_dns=`dig +short -x $random_server | sed 's/\.$//'`	
		if [ -n "$DEBUG" ]; then { echo "INFO: Randomly selected server name: $random_server_dns"; }; fi
	
		if ( rsync --files-from=$SYNC_FILE_LIST -ctuz --timeout="60" --stats rsync://$random_server/$current_sourcedir $current_destdir &> /dev/null ); then 

		#if ( rsync --files-from=$SYNC_FILE_LIST -ctuz --timeout="60" --stats rsync://$random_server/$current_sourcedir $current_destdir ); then 
			if [ -n "$DEBUG" ]; then { echo "NOTICE: rsync success from server  $random_server_dns  IP $random_server on attempt  $j "; }; fi
			break
		else 
			if [ -n "$DEBUG" ]; then { echo "WARNING: rsync fail  from server  $random_server_dns  IP $random_server on attempt  $j "; }; fi
		fi 
		if [ $j -eq $MAX_RETRIES ] ; then 
			echo "ERROR: rsync failed - MAX_RETRIES exceeded"
		fi 
	done

done