Mdns » Historial » Revisió 5
Revisió 4 (Pau Escrich, 24-10-2013 15:23) → Revisió 5/6 (Pau Escrich, 24-10-2013 18:19)
h1. Mdns: mesh DNS system 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. h3. Usage * /etc/init.d/mdns start -> starts the system (adds itself to the crontab) * /etc/init.d/mdns stop -> stops the system (removes itself from crontab) start * /etc/init.d/mdns reload -> update the data h3. 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) h3. Executation By default, even if there are not domains to publish in /etc/mdns/public file, the mdns script publish its own hostname.[ALL_ACCEPTED_TLDs] The accepted TLDs can be configured in the variables DOMAINS4 and DOMAINS6, for IPv4 and IPv6 respectivelly. So if someone publish "google.com" but your mdns instance is not accepting the ".com" TLD it will be discarted. <pre> root@UPClab104-1677:~# /etc/init.d/mdns start -> preparing bmx6 INFO uci_create_section: bmx6.cfg125cb5=syncSms INFO uci_save_option: bmx6.cfg125cb5.syncSms=mdns INFO uci_save_option: bmx6.cfg125cb5.syncSms=mdns INFO : --syncSms mdns -> adding addn-host entry to dnsmasq config file -> restarting dnsmasq daemon -> cleaning files -> publishing own IPv4 domains: UPClab104-1677.qmp -> publishing own IPv6 domains: UPClab104-1677.qm6 -> added remote domains google.qmp pau.qmp tita.qmp SApalafolls-ebb2.qmp = 10.228.206.65 -> added remote domains SApalafolls-ebb2.qm6 = 2012:0:0:ebb2::1 root@UPClab104-1677:~# ping google.qmp PING google.qmp (10.228.206.65): 56 data bytes 64 bytes from 10.228.206.65: seq=0 ttl=63 time=25.248 ms 64 bytes from 10.228.206.65: seq=1 ttl=64 time=1.655 ms 64 bytes from 10.228.206.65: seq=2 ttl=64 time=1.661 ms 64 bytes from 10.228.206.65: seq=3 ttl=64 time=1.692 ms 64 bytes from 10.228.206.65: seq=4 ttl=64 time=1.593 ms ^C --- google.qmp ping statistics --- 5 packets transmitted, 5 packets received, 0% packet loss round-trip min/avg/max = 1.593/6.369/25.248 ms root@UPClab104-1677:~# ping SApalafolls-ebb2.qm6 PING SApalafolls-ebb2.qm6 (2012:0:0:ebb2::1): 56 data bytes 64 bytes from 2012:0:0:ebb2::1: seq=0 ttl=64 time=1.886 ms 64 bytes from 2012:0:0:ebb2::1: seq=1 ttl=64 time=1.632 ms 64 bytes from 2012:0:0:ebb2::1: seq=2 ttl=64 time=1.679 ms 64 bytes from 2012:0:0:ebb2::1: seq=3 ttl=64 time=1.801 ms ^C --- SApalafolls-ebb2.qm6 ping statistics --- 4 packets transmitted, 4 packets received, 0% packet loss round-trip min/avg/max = 1.632/1.749/1.886 ms </pre> h3. Code <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>