Monitoring IP changes

CONFIG_FILE

### IPdetect configuration file
### (c) Mariusz Kaczmarczyk, 2005+
### Content of this file is subject to GPL version 2 license
### (http://www.gnu.org/licenses/gpl.html).

### This is shell include file, use rules for shell script files.
### Values should be VARIABLE='value' (no spaces around equal sign!).
### See 'man 1 bash' for details on how to write shell scripts.

# Force PATH to this value. For security reasons, do not change unless you
# really need to.
PATH='/sbin:/bin:/usr/sbin:/usr/bin'

# This sets the method of IP comparision, may be 'host' or 'last'.
# The first means comparing detected public IP to one resolved from
# CHECK_DOMAIN. You need to have 'host' util (from 'host' or 'dnsutils'
# package).
# The later means comparing detected IP with previously detected one.
# Doesn't need external programs.
# It's recommended to use 'last' for every minute check, and 'host' once per
# 15 minutes. Command line switch -p overrides this value.
IP_COMPARE_METHOD='last'

# Resolve this hostname, check its IP, if differs from detected one run
# script. Used when IP_COMPARE_METHOD is 'host' or -p switch is used. Can be
# overriden with -d switch.
CHECK_DOMAIN='alerticus.ru'

# This sets the method of retrieving page with current IP, may be 'browser'
# and, since ver. 0.6 'iface'. The first method uses HTTP to read external
# information page, as configured in ip_source file. The second gets the IP
# number of chosen interface. 'iface' is faster and so recommended choice
# when the program is run on the Linux router with public IP number on any
# interface.
# 'iface' method needs 'ifconfig' program in PATH. There should be support for
# 'iproute2' program instead if ifconfig in future versions of IPdetect.
# You can override this setting on command line with -r switch.
IP_RETRIEVE_METHOD='browser'

# If IP_RETRIEVE_METHOD = 'ifconfig', then set this to interface name to get
# IP number from.
# If you set this, and IP_RETRIEVE_METHOD is not 'iface', then iface is
# tried first, and if no address is supplied then selected method is used as
# fallback.
# Can be overriden with -i switch (use NULL special value or '' to disable
# this setting from command line).
# IP_INTERFACE='ppp0'

# Minimum IP check interval in seconds. Protects from abuses.
# Recommended value for most services: 55
CHECK_IP_INTERVAL=55

# Minimum script run interval in seconds. Protects from abuses.
# Recommended value depends on rules of your dynamic DNS provider.
# This is only used when problems with detecting right IP occurs.
UPDATE_IP_INTERVAL=290

# Turn on/off verbose output. May be 0 or 1.
# Recommended value is 0 for security reasons.
DEBUG_FLAG=0

# Events sent to log file.
# Can be combination of: 'change', 'nochange', 'error', 'forced'.
# Separate multiple entries with space, quote entire string if there's more
# than one entry.
LOG_EVENTS='change error forced';

# Whether to store or not failed IP update time (when update script returned
# non-zero exit code). May be 0 or 1. If not stored, IP update will probably
# be retried on next run of IPdetect. If stored, IP update will not be
# retried before end of update interval.
# You should know what you're doing if setting this to 0 (may then cause
# abusive use of dynamic DNS service).
STORE_FAILED_UPDATE=1

# IP retrieve timeout in seconds. Applied for browser program (depending on
# IP_RETRIEVE_METHOD and USE_BROWSERS). Default and recommended value is 12.
# IP_RETRIEVE_TIMEOUT=12

# Try to use HTTP browser in order below to retrieve IP in 'browser' mode.
# Supported programs are: curl, wget, links2, lynx. Separate multiple names with
# space. Programs are tried in given order.
# It's recommended to leave it undefined and use script's internal default list.
# USE_BROWSERS='curl wget links2 lynx'

# Max time for 'host' command to wait for response. After this timeout DNS
# query is considered lost and domain is considered unresolvable. This
# should be no more than 20 seconds if you run IPdetect once a minute, and
# no more than half of CHECK_IP_INTERVAL if you run less often. Default and
# recommended is 8.
# HOST_TIMEOUT=8

# Use this server to query for domains specified with CHECK_DOMAIN.
# Only used when IP_COMPARE_METHOD is 'host'.
# Hint: this is used as the DNS server parameter for 'host' command.
# Setting this is only recommended when you get right IP very much late
# after domain update (this problem can cause update script being run
# multiple times for the same event and may be treated as net abuse by some
# services!
# Remember to examine your logs after first updates).
# Use -n switch to override server address.
HOST_DNS_SERVER='ns1.ypdns.com'

# You can set user agent string for browser programs. This may be necessary
# for some sites providing IP address.
# Program's default is used when not set.
# DETECTION_USER_AGENT=''

# Run this script when IP change is detected
# Script gets 2 parameters: #1 is net IP address, #2 is CHECK_DOMAIN value.
# Remember to set secure enough permission to this file, as it probably will
# contain passwords or secret URLs (recommended: chmod 700 file_path).
# Use -s switch to override script location.
IP_CHANGE_EXEC='/usr/local/etc/ipdetect/change_run.sh'

# Send programs output to this file, instead of just loosing it. Sometimes
# useful for debuging. Disable in production environment.
# DEV_NULL=''

crontab

*/2 *   * * *   root    /usr/local/bin/ipdetect.sh
*/15 *  * * *   root    /usr/local/bin/ipdetect.sh -p host -r browser -c

IP_CHANGE_EXEC

#!/bin/sh

# Place your domain update commands here

# IP address, the second is CHECK_DOMAIN value from IPdetect.conf

# Ie. http://freedns.afraid.org/ gives you update URLs for dynamic
# domains, so you can put them into command:
# curl --silent <update_URL>
# This is tested and works very good.
# This script is run by IPdetect with 2 parameters: the first is the new
# IP address, the second is CHECK_DOMAIN value (from config file or -d)

# Check http://sf.net/docman/display_doc.php?docid=30187&group_id=147527
# for update code for various free dynamic DNS services.

# curl --silent http://freedns.afraid.org/dynamic/update.php?...

/usr/local/etc/ipdetect/ypdns.php $1

exit 0;

IP_SOURCES_FILE

# Place your IP source pages here (full address with http://)
# Sources are checked in given order

http://checkip.dyndns.org/
http://ipdetect.dnspark.com:8888/
# http://www.ipchicken.com/
# http://www.ip-number.com/index.asp
# http://www.lawrencegoetz.com/programs/ipinfo/
# http://www.cloudnet.com/support/getting_Connected/system.php
# http://www.mediacollege.com/internet/utilities/show-ip.shtml

ipdetect.sh

#!/bin/sh

### Content of this file is a subject to GPL version 2 license
### (http://www.gnu.org/licenses/gpl.html).

# help message
MSG_HELP="
IPdetect, ver. 0.6, (c) Mariusz Kaczmarczyk <koshmar@poczta.fm>.
IPv4 detection script for updating dynamic DNS services.
Free software. GPL version 2 license.

Usage:
`basename $0` [OPTIONS]

Options:
  -h|--help                          this help dialog
  -f|--force-update                  force IP update now
  -c|--force-check                   force IP check now
  -r|--retrieve-method brower|iface  override IP retrieve method
  -p|--compare-method host|last      override IP compare method
  -i|--interface-name interface      override interface used
  -d|--domain domain_name            domain to check/update
  -m|--messages-to file              send subprograms output to file (debug)
  -s|--update-script                 run this script on IP change
  -n|--dns-server nameserver         use this nameserver to resolve domain

There's no warranty of any kind for this software, you use it for your own 
risk! See README for help.
";

# Displays all commands executed
# Uncomment for maximum debug
# set -x;

# defaults
# do not alter these values, use configuration file instead
# (except for CONFIG_FILE of course :-))
CONFIG_FILE='/usr/local/etc/ipdetect/ipdetect.conf';
PATH='/sbin:/bin:/usr/sbin:/usr/bin';
CHECK_IP_INTERVAL=55;
UPDATE_IP_INTERVAL=290;
STORE_FAILED_UPDATE=1;
IP_RETRIEVE_METHOD='wget';
IP_COMPARE_METHOD='last';
CHECK_DOMAIN='';
DOMAIN_FILE='/usr/local/etc/ipdetect/check_domain';
IP_RETRIEVE_TIMEOUT=20;
IP_REGEXP='[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}';
IP_CHANGE_EXEC='/usr/local/etc/ipdetect/change_run.sh';
IP_SOURCES_FILE='/usr/local/etc/ipdetect/ip_sources';
LOG_DATE_FORMAT='%F,%T';
LOG_FILE='/var/log/ipdetect/ipdetect.log';
LOG_EVENTS='change error';
TMP_DIR="`dirname \`mktemp -u\``";
STORE_DIR='/var/lib/ipdetect';
IP_HTML_TMP_FILE='ipdetect-ip.tmp';
STORE_FILE='last_detect';
COMMENT_REGEX='^[:space:]*[#;]{1}.*';
# HOST_EXEC="`which host`";
HOST_TIMEOUT=8;
DEV_NULL='/dev/null';
HOST_DNS_SERVER='';
DEBUG_FLAG=0;
DETECTION_USER_AGENT='';
IP_INTERFACE='';
NULL_VALUE='NULL';
USE_BROWSERS='curl wget links2 lynx';
PRE_CHECK_INTERFACE=1;

# messages
MSG_1='ERROR: Invalid IP_RETRIEVE_METHOD, should be one of: browser, iface';
MSG_2='failed';
MSG_3='ERROR: Cannot retrieve valid IP';
MSG_4='NOTICE: Not checking IP - you need to wait';
MSG_5='more seconds';
MSG_6='ERROR: Cannot resolve domain';
MSG_7='ERROR: Cannot execute script';
MSG_8='ERROR: Cannot load config file';
MSG_9='ERROR: Cannot create store file';
MSG_10="ERROR: CHECK_DOMAIN must be set when IP_COMPARE_METHOD = 'host'";
MSG_11='ERROR: Temporary file not writable';
MSG_12='NOTICE: Not updating IP - you need to wait';
MSG_13="ERROR: you have to set IP_INTERFACE for IP_RETRIEVE_METHOD = 'iface'";
MSG_14='ERROR: Unknown parameter';
MSG_15='ERROR: Invalid IP_COMPARE_METHOD, should be one of: host, last';

# error codes
ERR_OK_NOCHANGE=0;
ERR_OK_CHANGE=127;
ERR_NOCONFFILE=1;
ERR_BADSTOREPATH=2;
ERR_BADRETRMETHOD=3;
ERR_NOVALIDIP=4;
ERR_BADCOMPMETHOD=5;
ERR_HOSTRESOLVERR=6;
ERR_EXECFAIL=7;
ERR_BADDOMAINNAME=8;
ERR_NOIFACE=10;
ERR_BADPARAM=11;

# include config file
if [ ! -f "${CONFIG_FILE}" -o ! -r "${CONFIG_FILE}" ]; then
	echo "${MSG_8}: ${CONFIG_FILE}";
	exit ${ERR_NOCONFFILE};
fi;
. "${CONFIG_FILE}";

# startup values
FORCE_UPDATE_FLAG=0;
FORCE_CHECK_FLAG=0;
EXEC_FLAG=0;
CHANGE_FLAG=0;

# check command line parameters
for X1 in `seq 1 $#`; do
	case "$1" in
		'-h'|'--help')
			echo "${MSG_HELP}";
			exit ${ERR_OK_NOCHANGE};
		;;
		'-f'|'--force-update')
			FORCE_UPDATE_FLAG=1;
			shift 1;
		;;
		'-c'|'--force-check')
			FORCE_CHECK_FLAG=1;
			shift 1;
		;;
		'-r'|'--retrieve-method')
			IP_RETRIEVE_METHOD="$2";
			case "${IP_RETRIEVE_METHOD}" in
				'browser')
					PRE_CHECK_INTERFACE=0;
				;;
			esac;
			shift 2;
		;;
		'-p'|'--compare-method')
			IP_COMPARE_METHOD="$2";
			shift 2;
		;;
		'-i'|'--interface-name')
			IP_INTERFACE="$2";
			shift 2;
		;;
		'-d'|'--domain')
			CHECK_DOMAIN="$2";
			IP_COMPARE_METHOD='host';
			shift 2;
		;;
		'-m'|'--messages-to')
			DEV_NULL="$2";
			shift 2;
		;;
		'-s'|'--update-script')
			IP_CHANGE_EXEC="$2";
			shift 2;
		;;
		'-n'|'--dns-server')
			HOST_DNS_SERVER="$2";
			IP_COMPARE_METHOD='host';
			shift 2;
		;;
		'')
			# ignore	
		;;
		*)
			echo "${MSG_14} '$1'";
			exit ${ERR_BADPARAM};
		;;
	esac;
done;

# prepare some essential variable values
IP_HTML_TMP_PATH="${TMP_DIR}/${IP_HTML_TMP_FILE}";
STORE_PATH="${STORE_DIR}/${STORE_FILE}";
S70_NOW="`date +%s`";

# reset variables that have NULL special value
if [ "${IP_INTERFACE}" = "${NULL_VALUE}" ]; then
	IP_INTERFACE='';
fi;
if [ "${HOST_DNS_SERVER}" = "${NULL_VALUE}" ]; then
	HOST_DNS_SERVER='';
fi;

# define functions
debug_msg() {
	if [ "${DEBUG_FLAG}" -gt 0 ]; then
		echo "DEBUG: $1" >&2;
	fi;
};

log_output() {
	LOG_EVENT_ID="$1";
	SCRIPT_EXIT_CODE="$2";
	touch "${LOG_FILE}";
	LOG_FLAG="`echo " ${LOG_EVENTS} " | grep -o -E " ${LOG_EVENT_ID} "`";
	if [ -z "${LOG_FLAG}" ]; then
		return 1;
	fi;
	ITEM_1="-${LOG_EVENT_ID}-";
	ITEM_2="`date "+${LOG_DATE_FORMAT}"`";
	ITEM_3="${IP_FOUND_METHOD:=$NULL_VALUE}";
	ITEM_4="(${IP_SOURCE_NOW:=$NULL_VALUE})";
	ITEM_5="${IP_NOW:=$NULL_VALUE}";
	ITEM_6="${IP_COMPARE_METHOD:=$NULL_VALUE}";
	case "${IP_COMPARE_METHOD}" in
		'last')
			ITEM_7='';
			ITEM_8="${LAST_IP:=$NULL_VALUE}";
		;;
		'host')
			ITEM_7="(${CHECK_DOMAIN})";
			ITEM_8="${HOST_IP:=$NULL_VALUE}";
		;;
		*)
			return 1;
		;;
	esac;
	ITEM_9="result:${SCRIPT_EXIT_CODE}";
	case "${LOG_EVENT_ID}" in
		'change'|'forced')
			ITEM_10="update:${UPDATE_SCRIPT_STATUS}";
		;;
		'nochange'|'error')
			ITEM_10="update:$NULL_VALUE";
		;;
		*)
			return 1;
		;;
	esac;
	TMP_LOG_ITEM="${ITEM_1} ${ITEM_2} ${ITEM_3}${ITEM_4} ${ITEM_5} ${ITEM_6}${ITEM_7} ${ITEM_8} ${ITEM_9} ${ITEM_10}";
	echo ${TMP_LOG_ITEM} >>"${LOG_FILE}";
	return 0;
};

ip_from_host() {
	HOST_IP='';
	if [ -z "$1" ]; then
		return 1;
	fi;
	HOST_CMD_OUT=`host -t A -W ${HOST_TIMEOUT} "$1" ${HOST_DNS_SERVER} 2>${DEV_NULL}`;
	HOST_IP=`echo ${HOST_CMD_OUT} |grep -o -E ${IP_REGEXP} |tail -n 1`;
	if [ -z "${HOST_IP}" ]; then
		HOST_CMD_OUT=`host -t A -s ${HOST_TIMEOUT} "$1" ${HOST_DNS_SERVER} 2>"${DEV_NULL}"`;
		HOST_IP=`echo ${HOST_CMD_OUT} |grep -o -E "${IP_REGEXP}" |tail -n 1`;
	fi;
	return 0;
};

retr_ip_browser() {
	if [ -z "$1" ]; then
		return 1;
	fi;
	if [ -z "${USE_BROWSERS}" ]; then
		return 2;
	fi;
	for X1 in ${USE_BROWSERS}; do
		BR_PATH="`which $X1`";
		debug_msg "use_browser: $X1 -> '$BR_PATH'";
		if [ -n "${BR_PATH}" ]; then
			case "${X1}" in
				'curl')
					if [ -n "${DETECTION_USER_AGENT}" ]; then
						PAGE_SRC=`"${BR_PATH}" --silent --connect-timeout ${IP_RETRIEVE_TIMEOUT} --user-agent "${DETECTION_USER_AGENT}" --url "$1" 2>"${DEV_NULL}"`;
					else
						PAGE_SRC=`"${BR_PATH}" --silent --connect-timeout ${IP_RETRIEVE_TIMEOUT} --url "$1" 2>"${DEV_NULL}"`;
					fi;
				;;
				'wget')
					if [ -n "${DETECTION_USER_AGENT}" ]; then
						PAGE_SRC=`"${BR_PATH}"  --quiet --timeout=${IP_RETRIEVE_TIMEOUT} --output-document=- --user-agent "${DETECTION_USER_AGENT}" "$1" 2>"${DEV_NULL}"`;
					else
						PAGE_SRC=`"${BR_PATH}"  --quiet --timeout=${IP_RETRIEVE_TIMEOUT} --output-document=- "$1" 2>"${DEV_NULL}"`;
					fi;
				;;
				'lynx')
					if [ -n "${DETECTION_USER_AGENT}" ]; then
						PAGE_SRC=`"${BR_PATH}" -dump -connect_timeout=${IP_RETRIEVE_TIMEOUT} --useragent "${DETECTION_USER_AGENT}" "$1" 2>"${DEV_NULL}"`;
					else
						PAGE_SRC=`"${BR_PATH}" -dump -connect_timeout=${IP_RETRIEVE_TIMEOUT} "$1" 2>"${DEV_NULL}"`;
					fi;
				;;
				'links2')
					if [ -n "${DETECTION_USER_AGENT}" ]; then
						PAGE_SRC=`"${BR_PATH}" -dump -receive-timeout ${IP_RETRIEVE_TIMEOUT} -fake-user-agent "${DETECTION_USER_AGENT}" "$1" 2>"${DEV_NULL}"`;
					else
						PAGE_SRC=`"${BR_PATH}" -dump -receive-timeout ${IP_RETRIEVE_TIMEOUT} "$1" 2>"${DEV_NULL}"`;
					fi;
				;;
			esac;
		fi;
		if [ -n "${PAGE_SRC}" ]; then
			RETRIEVED_IP=`echo "${PAGE_SRC}" |grep -E -o "${IP_REGEXP}" |uniq`;
		fi;
		if [ -n "${RETRIEVED_IP}" ]; then
			echo "${RETRIEVED_IP}";
			return 0;
		fi;
	done;
	return 3;
}

# create store file (for last IP, detection and refresh time)
touch "${STORE_PATH}";
if [ -f "${STORE_PATH}" ]; then
	. "${STORE_PATH}";
else
	echo "${MSG_9}: ${STORE_PATH}";
	exit ${ERR_BADSTOREPATH};
fi;

# check last detection time, abort if checking too short after last one and not forced check/update
# check is applied for 'browser' method
# check if given retrieve method is valid
case "${IP_RETRIEVE_METHOD}" in
	'iface')
		# do nothing
	;;
	'browser')
		if [ -n "${LAST_DETECTION}" ]; then
			LAST_DET_FROM_NOW=`expr ${S70_NOW} - ${LAST_DETECTION}`;
			if [ ${LAST_DET_FROM_NOW} -lt ${CHECK_IP_INTERVAL} -a ${FORCE_UPDATE_FLAG} -le 0 -a ${FORCE_CHECK_FLAG} -le 0 ]; then
				WAIT_FROM_NOW=`expr ${CHECK_IP_INTERVAL} - ${LAST_DET_FROM_NOW}`;
				echo "${MSG_4} ${WAIT_FROM_NOW} ${MSG_5}";
				exit ${ERR_OK_NOCHANGE};
			fi;
		fi;
	;;
	*)
		echo "${MSG_1}";
		exit ${ERR_BADRETRMETHOD};
	;;
esac;

# IP address not yet found
IP_FOUND_STATUS=0;

# check interface IP
if [ -n "${IP_INTERFACE}" ]; then
	if [ ${PRE_CHECK_INTERFACE} -gt 0 ]; then
		TMP_IPADDR=`ifconfig "${IP_INTERFACE}" |grep -E -o "inet( addr)?:${IP_REGEXP}" |uniq |cut -f 2 -d ':' 2>"${DEV_NULL}"`;
		if [ -n "${TMP_IPADDR}" ]; then
			IP_FOUND_STATUS=1;
			IP_FOUND_METHOD='iface';
			IP_SOURCE_NOW="${IP_INTERFACE}";
			debug_msg "retrieve_method: iface";
			debug_msg "retrieve_source: ${IP_SOURCE_NOW}";
			debug_msg "retrieve_result: ${TMP_IPADDR}";
		else
			debug_msg "retrieve_method: iface";
			debug_msg "retrieve_source: ${IP_SOURCE_NOW}";
			debug_msg "retrieve_result: ${MSG_2}";
		fi;
	fi;
else
	case "${IP_RETRIEVE_METHOD}" in
		'iface')
			log_output 'error' ${ERR_NOIFACE};
			echo "${MSG_13}";
			exit ${ERR_NOIFACE};
		;;
	esac;
fi;

# check current public IP
for TMP_IP_SRC in `cat "${IP_SOURCES_FILE}" | grep -v -E "${COMMENT_REGEX}" | tr ' ' '_'`; do
	if [ ${IP_FOUND_STATUS} -le 0 ]; then
		if [ -z "${TMP_IPADDR}" ]; then
			debug_msg "retrieve_method: ${IP_RETRIEVE_METHOD}";
			case "${IP_RETRIEVE_METHOD}" in
				'browser')
					TMP_IPADDR=`retr_ip_browser "${TMP_IP_SRC}"`;
				;;
				'iface')
					# do nothing
				;;
			esac;
		fi;
		if [ -n "${TMP_IPADDR}" ]; then
			IP_SOURCE_NOW="${TMP_IP_SRC}";
			IP_FOUND_STATUS=2;
			IP_FOUND_METHOD="${IP_RETRIEVE_METHOD}";
			debug_msg "retrieve_source: ${IP_SOURCE_NOW}";
			debug_msg "retrieve_result: ${TMP_IPADDR}";
		else
			debug_msg "retrieve_source: ${IP_SOURCE_NOW}";
			debug_msg "retrieve_result: ${MSG_2}";
		fi;
	fi;
done;

# exit when no valid IP address found
if [ -z "${TMP_IPADDR}" ]; then
	log_output 'error' ${ERR_NOVALIDIP};
	echo "${MSG_3}";
	exit ${ERR_NOVALIDIP};
fi;
IP_NOW="${TMP_IPADDR}";
LAST_DETECTION="${S70_NOW}";

# check compare method
# compare last/host and current IP
case "${IP_COMPARE_METHOD}" in
	'last')
		debug_msg "compare_method: ${IP_COMPARE_METHOD}";
		debug_msg "last_ip: ${LAST_IP}";
		if [ "${LAST_IP}" != "${IP_NOW}" ]; then
			EXEC_FLAG=1;
			CHANGE_FLAG=1;
		fi;
	;;
	'host')
		debug_msg "compare_method: ${IP_COMPARE_METHOD}";
		if [ -f "${DOMAIN_FILE}" ]; then
			CHECK_DOMAIN_FORCE=`cat --squeeze-blank "${DOMAIN_FILE}"`;
		fi;
		if [ -n "${CHECK_DOMAIN_FORCE}" ]; then
			CHECK_DOMAIN="${CHECK_DOMAIN_FORCE}";
		fi;
		if [ -z "${CHECK_DOMAIN}" ]; then
			echo "${MSG_10}";
			exit ${ERR_BADDOMAINNAME};
		fi;
		ip_from_host "${CHECK_DOMAIN}";
		if [ -z "${HOST_IP}" ]; then
			log_output 'error' ${ERR_HOSTRESOLVERR};
			echo "${MSG_6}: ${CHECK_DOMAIN}";
			exit ${ERR_HOSTRESOLVERR};
		fi;
		debug_msg "host: ${CHECK_DOMAIN}";
		debug_msg "host_ip: ${HOST_IP}";
		debug_msg "current_ip: ${IP_NOW}";
		if [ "${HOST_IP}" != "${IP_NOW}" ]; then
			EXEC_FLAG=1;
			CHANGE_FLAG=1;
		fi;
	;;
	*)
		echo "${MSG_15}";
		exit ${ERR_BADCOMPMETHOD};
	;;
esac;
debug_msg "change: ${CHANGE_FLAG}";
debug_msg "exec: ${EXEC_FLAG}";

# execute update script
if [ "${FORCE_UPDATE_FLAG}" -gt 0 ]; then
	EXEC_FLAG=1;
fi;
debug_msg "forced_update: ${FORCE_UPDATE_FLAG}";
if [ "${EXEC_FLAG}" -gt 0 ]; then
	if [ ! -x "${IP_CHANGE_EXEC}" ]; then
		echo "${MSG_7}";
		log_output 'error' ${IP_CHANGE_EXEC};
		exit ${ERR_EXECFAIL};
	fi;
	if [ -n "${LAST_UPDATE}" ]; then
		LAST_UPD_FROM_NOW=`expr ${S70_NOW} - ${LAST_UPDATE}`;
		if [ "${LAST_UPD_FROM_NOW}" -lt "${UPDATE_IP_INTERVAL}" -a "${FORCE_UPDATE_FLAG}" -le 0 ]; then
			WAIT_FROM_NOW=`expr ${UPDATE_IP_INTERVAL} - ${LAST_UPD_FROM_NOW}`;
			echo "${MSG_12} ${WAIT_FROM_NOW} ${MSG_5}";
			exit ${ERR_OK_CHANGE};
		fi;
	fi;
	debug_msg "run: '${IP_CHANGE_EXEC} "${IP_NOW}" "${CHECK_DOMAIN}"'";
	if [ "${DEBUG_FLAG}" -gt 0 ]; then
		"${IP_CHANGE_EXEC}" "${IP_NOW}" "${CHECK_DOMAIN}";
	else
		"${IP_CHANGE_EXEC}" "${IP_NOW}" "${CHECK_DOMAIN}" 2>&1 >"${DEV_NULL}";
	fi;
	UPDATE_SCRIPT_STATUS=$?;
	if [ "${CHANGE_FLAG}" -gt 0 ]; then
		log_output 'change' ${ERR_OK_CHANGE};
	else
		log_output 'forced' ${ERR_OK_NOCHANGE};
	fi;
	if [ ${UPDATE_SCRIPT_STATUS} != 0 -a "${STORE_FAILED_UPDATE}" -le 0 ]; then
		# do nothing for now
		echo '' >"${DEV_NULL}";
	else
		LAST_UPDATE="${S70_NOW}";
	fi;
else
	log_output 'nochange';
	debug_msg "run: -";
fi;

# save values to store file
LAST_IP="${IP_NOW}";
echo "LAST_IP='${LAST_IP}'" >"${STORE_PATH}";
echo "LAST_DETECTION=${LAST_DETECTION}" >>"${STORE_PATH}";
echo "LAST_UPDATE=${LAST_UPDATE}"  >>"${STORE_PATH}";

# goodbye, no errors
if [ "${CHANGE_FLAG}" -gt 0 ]; then
	exit ${ERR_OK_CHANGE};
fi;
exit ${ERR_OK_NOCHANGE};