bmx6

h1. Mdns

This is an example of bmx6 SMS plugin utilization. It is a distributed DNS system where every node publish the domains it is managing.

The current implementation is done for working in OpenWRT with the Dnsmasq daemon.

Usage:

* /etc/init.d/mdns start

* /etc/init.d/mdns start

* /etc/init.d/mdns reload

Files:

* /etc/mdns/public contains the list of domains we wanto to announce in the network

* /etc/mdns/hosts contains a list of "IP -> domain" which have been obtained from the network (dnsmasq looks on it)

<pre>

#!/bin/sh

#    Copyright (C) 2013 Pau Escrich <p4u@dabax.net>

#

#    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 2 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, write to the Free Software Foundation, Inc.,

#    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

#

#    The full GNU General Public License is included in this distribution in

#    the file called "COPYING".

# Configuration variables                                     

MDNS_DIR="/etc/mdns"                                                

HOSTF="$MDNS_DIR/hosts"                                            

MY_DOMAINS="$MDNS_DIR/public"                                     

DOMAINS4="qmp"

DOMAINS6="qm6"

SMSF="/var/run/bmx6/sms/sendSms/mdns"                                       

SMSR="/var/run/bmx6/sms/rcvdSms"                                            

DNSMASQ="/etc/dnsmasq.conf"                                     

DNSMASQ_PID="/var/run/dnsmasq.pid"

# Optional

IPV4=""

IPV6=""

start() {

	if ! cat /etc/crontabs/root | grep mdns > /dev/null; then

		echo "/10 * * * * /etc/init.d/mdns reload > /tmp/log/mdns.log" >> /etc/crontabs/root

		/etc/init.d/cron enable

		/etc/init.d/cron start

	fi

	/etc/init.d/mdns reload

	}

stop() {

	sed -i -e '/.*\/etc\/init\.d\/mdns reload > \/tmp\/log\/mdns\.log$/d' /etc/crontabs/root

	/etc/init.d/cron restart

	}

reload() {

	init

	publish_my_domains

	get_domains

	finish	

}

refresh() { 

	reload

}

# Code

error() {

	echo "ERROR: $@"

	exit 1

}

log() {

	echo -e "-> $@"

}

init() {

	log "preparing bmx6"

	bmx6 -c --syncSms mdns

	[ $? -ne 0 ] && error "cannot configure bmx6 daemon"

	cat $DNSMASQ | egrep "^addn-hosts=$HOSTF" -q || {

		log "adding addn-host entry to dnsmasq config file"

		echo "addn-hosts=$HOSTF" >> $DNSMASQ

		log "restarting dnsmasq daemon"

		/etc/init.d/dnsmasq restart

	}

	ps | grep dnsmasq -q || error "dnsmasq not running"

	log "cleaning files"

	[ -f $SMSF ] && rm -f $SMSF

	touch $SMSF

	[ -f $HOSTF ] && rm -f $HOSTF

	touch $HOSTF	

	[ ! -d $MDNS_DIR ] && mkdir -p $MDNS_DIR

	touch $MY_DOMAINS

}

check_domain() {

		local v="$1"

		local d="$2"

		local valid=1

		local domains=""

		[ $v == "4" ] && domains="$DOMAINS4"

		[ $v == "6" ] && domains="$DOMAINS6"

		[ $v == "all" ] && domains="$DOMAINS4 $DOMAINS6"

		for D in $domains; do

			echo "$d" | egrep "\.$D"$ -q && valid=0 && break

		done 

		return $valid

}

get_my_domains() {

	local v=${1:-4}

	local my_domains=""

	local domains=""

	local d

	for d in $(cat $MY_DOMAINS); do

		check_domain $v $d && my_domains="$d $my_domains"

	done

	[ "$v" == "4" ] && domains="$DOMAINS4"

	[ "$v" == "6" ] && domains="$DOMAINS6"

	for d in $domains; do

		my_domains="$(cat /proc/sys/kernel/hostname).$d $my_domains"

	done

	echo $my_domains

}

get_my_ip4() {

	[ -z $IPV4 ] && \

	bmx6 -cp | grep tun4Address | awk '{print $2}' | awk -F / '{print $1}' || \

	echo "$IPV4"

}

get_my_ip6() {

	[ -z $IPV4 ] && \

	bmx6 -cp | grep tun6Address | awk '{print $2}' | awk -F / '{print $1}' || \

	echo "$IPV6"

}

publish_my_domains() {

	local d domains

	local ip4="$(get_my_ip4)"

	local ip6="$(get_my_ip6)"

	[ -z "$ip4$ip6" ] && error "cannot get ip address"

	[ -n "$ip4" ] && {

		domains="$(get_my_domains 4)"

		log "publishing own IPv4 domains: $domains"

		echo "$ip4 $domains" >> $SMSF

		echo "$ip4 $domains" >> $HOSTF

	}

	[ -n "$ip6" ] && {

		domains="$(get_my_domains 6)"

		log "publishing own IPv6 domains: $domains"

		echo "$ip6 $domains" >> $SMSF

		echo "$ip6 $domains" >> $HOSTF

	}

}

get_domains() {

	local f d domline ip line n i

	ls $SMSR/*:mdns 2>/dev/null >/dev/null && {

	  # for each received file	

	  for f in $SMSR/*:mdns; do

		n=$(cat $f | wc -l)

		# for each line inside the file

		for i in $(seq $n); do

			line=$(cat $f | awk "NR==$i")

			ip="$(echo $line | awk '{print $1}')"

			[ -z $ip ] && continue

			domains=""

			# for each domain (first is IP)

			for d in $(echo "$line" | awk '{$1=""; print $0}'); do

				check_domain all $d && domains="$d $domains"

			done

			[ -n "$domains" ] && echo "$ip $domains" >> $HOSTF

			log "added remote domains $domains= $ip"

	  done

  done 

	  } || log "not published domains found in the network"

}

finish() {

	kill -SIGHUP $(cat $DNSMASQ_PID)

}

$@

</pre>