init commit

Date: 2012-05-10

Time-stamp: <2012-05-10>

the ddclient package seems *weak*.

it does not keep the domain up-to-date.

    //since by default there is no error report or log, I can't know the reason.

    //the thing I know is the IP for my domain gets out-dated.

it does not keep a log.

    //ddclient can log to syslog. default is no log though.

it does not report errors.

* features

** works by running command in crontab

** send email to local admin when update IP fail.

   send email to local admin when network is down. i.e. can't do dig or curl

   at all.

** log to syslog, default target is /var/log/ddclient-http.log

   auto create syslog filter rule.

   auto create logrotate rule.

** easy installable.

   use make install or make install-deb.

   'make deb' will create a .deb package.

** 

* dependencies

  low level:

  shell

  high level:

  curl

  dig

  make

* TODO split config from source code.

  config variables should be set in /etc/ddclient-http.conf

  and it can be sourced by the source code.

* before I write configs and install script for this http client.

  let's first see if I can config ddclient the way I wish it to be.

  enable log:

  -syslog

  -facility ?

  enable retry:

  -retry

  can I use ifconfig.me to get IP?

  currently I set in /etc/ddclient.conf

  use=web

  but I don't know which provider does it use.

  -web provider|url default: dyndns

** test get IP

   /usr/sbin/ddclient -options query,noexec -use=web -web http://ifconfig.me

   no good. it tries to request a new binding.

   still no good. it requires root. query seems print binded IP on ddns

   server. not the IP that is going to be used?

** when using -use=cmd, what if cmd fail?

   -use=cmd                    : obtain IP from the -cmd {external-command}.

   -cmd program          : obtain IP address from by calling {program}.

   -cmd-skip pattern     : skip any IP addresses before 'pattern' in the output of {cmd}.

** I believe it's not wise to use ddclient.

   so I will continue this project.

default: install

install: install-dependence

	install bin/ddclient-http /usr/local/bin/

	install -m 644 etc/logrotate /etc/logrotate.d/ddclient-http

	install -m 644 etc/rsyslog-filter /etc/rsyslog.d/ddclient-http.conf

	install -m 644 etc/crontab /etc/cron.d/ddclient-http

# log file must be created before restarting rsyslog.

	install -m 640 -o root -g adm /dev/null /var/log/ddclient-http.log

# note: reload will not work. a full restart is required.

	/etc/init.d/rsyslog restart

install-dependence:

	./utils/install-dependence

uninstall:

	rm -f /usr/local/bin/ddclient-http /etc/logrotate.d/ddclient-http /etc/rsyslog.d/ddclient-http.conf /etc/cron.d/ddclient-http

	echo -e "you may optionally restart rsyslog:\n    \

/etc/init.d/rsyslog restart"

purge: uninstall

	rm -f /var/log/ddclient-http.log*

.PHONY: install install-dependence uninstall purge

#!/bin/sh

# this is designed to run in crontab.

# run 'make install' to install this program.

PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin

# exit codes

GET_MYIP_FAILED=1

DIG_FAILED=2

UPDATE_REQUEST_FAILED=3

UPDATE_REJECTED=4

# stores responses from remote DDNS provider's server.  usually it will be

# very short, like a word or two. but if there is a server error, it could be

# long.

HTTP_RESPONSE=/tmp/ddclient-http-api.html

# which host to update and it's credentials.

USERNAME=s12nospam@hotmail.com

PASSWORD=songyl

HOSTNAME=sylecn01.dnsd.me

# Usage: log [MESSAGE..]

log() {

	logger -t ddclient_http "$@"

}

# set MYIP variable to my internet IP address.

# Returns true on success, false on failure.

get_myip() {

	MYIP=`curl -s http://ifconfig.me`

	CURL_EXIT_CODE=$?

	if [ "$CURL_EXIT_CODE" -eq 0 ]; then

		return 0

	else

		log "get_myip() failed. curl exit code is $CURL_EXIT_CODE."

		exit $GET_MYIP_FAILED

	fi

}

# returns true if domain is outdated. returns false otherwise.

require_update() {

	OLDIP=`dig +short sylecn01.dnsd.me`

	# TODO dig can fail when network is down or DNS server is blocked by

	# GFW. check dig command's exit code.

	#

	# dig always return 0! if no A record is found, OLDIP will be empty.

	if [ -z "$OLDIP" ]; then

		log "Can't get current binding IP. dig failed."

		exit $DIG_FAILED

	fi

	if [ "$OLDIP" = "$MYIP" ]; then

		log "$HOSTNAME is up-to-date. IP is $OLDIP."

		return 1

	else

		log "$HOSTNAME is out-dated. Old IP is $OLDIP. New IP is $MYIP."

		return 0

	fi

}

do_update() {

	log "update $HOSTNAME using IP $MYIP"

	curl -s -o "$HTTP_RESPONSE" -u "$USERNAME":"$PASSWORD" \

		"https://www.dnsdynamic.org/api/?hostname=$HOSTNAME&myip=$MYIP"

	# check curl EXIT CODES

	CURL_EXIT_CODE=$?

	case $CURL_EXIT_CODE in

		0) log "curl ok." ;;

		6) log "curl error: Couldn't resolve host." ;;

		7) log "curl error: Failed to connect to host." ;;

		28) log "curl error: Operation timeout." ;;

		*) log "curl error: exit code $CURL_EXIT_CODE.";;

	esac

	if  [ $CURL_EXIT_CODE -ne 0 ]; then

		exit $UPDATE_REQUEST_FAILED

	fi

	# check HTTP_RESPONSE

	case "$HTTP_RESPONSE" in

		good) log "good: update accepted."

			return 0 ;;

		nochg) log "nochg: IP not changed." ;;

		badauth) log "badauth: user or password incorrect." ;;

		abuse) log "abuse: hostname is blocked for update abuse." ;;

		dnserr) log "dnserr: DNS error encountered." ;;

		911) log "911: server problem." ;;

		*) log "Error: return code is ${HTTP_RESPONSE}." ;;

	esac

	exit $UPDATE_REJECTED

}

# main

if get_myip; then

	if require_update; then

		do_update

	fi

fi

# /etc/cron.d/anacron: crontab entries for the anacron package

SHELL=/bin/sh

PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin

*/2 * * * *    sylecn    /usr/local/bin/ddclient-http