| 1 | #!/bin/sh -
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| 2 | #
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| 3 | # KISS Dynamic DNS service (no locking (hint lockf wrapper), no advanced checking)
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| 4 | # 'ping' is based on ssh call or CGI call
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| 5 | #
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| 6 | # = INSTALL - SSH =
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| 7 | # 1) Make sure to allow rndc reload in your sudoers file
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| 8 | # sudo_user ALL=(ALL) NOPASSWD: /usr/sbin/rndc reload
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| 9 | # 2) prefix your ssh authorized key to allow only this script
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| 10 | # command="/home/rvdzwet/dyndns.sh"
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| 11 | # 3) Call for the remote host like this
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| 12 | # ssh -a -p 1022 -i id_rsa zweot.vanderzwet.net `hostname`
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| 13 | #
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| 14 | # = INSTALL - CGI =
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| 15 | # XXX:TODO
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| 16 | #
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| 17 | # = USAGE =
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| 18 | # Make sure your DNS entries has zones like this to allow remote updating
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| 19 | # example 60 IN A 192.0.32.10
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| 20 | # example 60 IN TXT "dyndns"
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| 21 | #
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| 22 | # Rick van der Zwet <info@rickvanderzwet.nl>
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| 23 | #
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| 24 | ZONE='vanderzwet.net'
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| 25 | ZONEFILE="/etc/namedb/master/$ZONE"
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| 26 |
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| 27 |
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| 28 | ### NO USER EDITABLE PARTS BELOW HERE ###
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| 29 | # SSH specific details
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| 30 | HOSTNAME=`echo $SSH_ORIGINAL_COMMAND | tr -c -d '[a-zA-Z0-9\-_\.]' | cut -d ' ' -f 1 | cut -d '.' -f 1`
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| 31 | REMOTEIP=`echo $SSH_CLIENT | cut -d ' ' -f 1`
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| 32 |
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| 33 | # Tmpfile creation for editing 'in between'
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| 34 | TMPFILE=`mktemp -t $(basename $0 .sh).XXX`
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| 35 | trap "rm -f $TMPFILE; exit 1" 0 1 2 15
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| 36 | cp $ZONEFILE $TMPFILE || exit 1
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| 37 |
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| 38 |
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| 39 | # See whether there exists a dynamic entry for it, like this
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| 40 | # example 60 IN A 192.0.32.10
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| 41 | # example 60 IN TXT "dyndns"
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| 42 | LINENR=`awk -v host=$HOSTNAME '{if ($1 == host) { if ($4 == "A") { line=NR } else if($5 ~ /dyndns/) {print line; exit} }}' $TMPFILE`
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| 43 | if [ -z "$LINENR" ]; then
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| 44 | echo "$HOSTNAME does not exists or is not marked as dynamic"
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| 45 | exit 1
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| 46 | fi
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| 47 |
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| 48 | # Do we need to update the entry
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| 49 | OLDIP=`awk -v linenr=$LINENR 'NR==linenr {print $5}' $TMPFILE`
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| 50 | if [ "$OLDIP" = "$REMOTEIP" ]; then
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| 51 | echo "No changes"
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| 52 | exit 0
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| 53 | fi
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| 54 |
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| 55 | # Update the entry
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| 56 | sed -i '' "${LINENR}s/$OLDIP/$REMOTEIP/" $TMPFILE || exit 1
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| 57 |
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| 58 | # Update serial of zone name
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| 59 | # YYYYMMDDNN where NN is from 00 till 99
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| 60 | TODAY=`date "+%Y%m%d"`
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| 61 | OLDSERIAL=`sed -n '1,10s/.*\([0-9]\{10\}\).*/\1/p' $TMPFILE`
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| 62 | if [ -z "$OLDSERIAL" ]; then
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| 63 | echo "Error Unable to find SERIAL of zone"
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| 64 | exit 1
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| 65 | fi
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| 66 | if `echo $OLDSERIAL | grep -q "^$TODAY"`; then
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| 67 | if `echo $OLDSERIAL | grep -q '99$'`; then
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| 68 | echo "Sorry domain update limit reached no more updates for today"
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| 69 | exit 1
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| 70 | fi
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| 71 | NEWSERIAL=`expr $OLDSERIAL + 1`
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| 72 | else
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| 73 | NEWSERIAL="${TODAY}00"
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| 74 | fi
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| 75 | sed -i '' "1,10s/$OLDSERIAL/$NEWSERIAL/g" $TMPFILE || exit 1
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| 76 |
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| 77 | # Install and activate
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| 78 | if \! `/usr/sbin/named-checkzone -q $TMPFILE $ZONE`; then
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| 79 | echo "New zone failed to validate"
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| 80 | exit 1
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| 81 | fi
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| 82 | cp $TMPFILE $ZONEFILE
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| 83 | sudo /usr/sbin/rndc reload
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| 84 | echo "Entry updated"
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