From mboxrd@z Thu Jan  1 00:00:00 1970
From: erik quanstrom <quanstro@quanstro.net>
Date: Mon, 20 Aug 2012 21:59:02 -0400
To: 9fans@9fans.net
Message-ID: <1748b045cc1050dc736dc683b0ec4db1@brasstown.quanstro.net>
In-Reply-To: <2D9EDA28-F8AC-441B-82B5-1A4BD08ED0F5@corpus-callosum.com>
References: <2D9EDA28-F8AC-441B-82B5-1A4BD08ED0F5@corpus-callosum.com>
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Subject: Re: [9fans] dns
Topicbox-Message-UUID: ad41e244-ead7-11e9-9d60-3106f5b1d025

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i'm using a modified version of dns.  i found that aktomi
redirections too unreliable.  even so, i still get crashes, which have
become more frequent in recent weeks.  i've attached a copy of
"restartdns" which is ment to be called from cron on short intervals.

contrib quanstro/ndb has the whole nine yards.

one of these days i will redo dns with a better (and maintainable)
structure.  :-).  but please beat me to it.

- erik
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#!/bin/rc
rfork en
nl=3D'
'
mailto=3D(quanstro)
allow=3D(ladd)
recursive=3D()
gcidr =3D (
	# only blocks that can map to google's a records
	72.14.192.0/18
	74.125.0.0/16
	209.85.128.0/17
	216.239.32.0/19
	173.194.0.0/16
)

if(! ~ `{cat /dev/user} `{cat /dev/hostowner}){
	echo 'restartdns: must be hostowner' >[1=3D2];
	exit user
}

9fs other

fn syslog{
	echo $sysname `{date} restartdns: $* > /sys/log/dns
}

fn pgroup{
	ifs=3D$nl g=3D`{cat /proc/$1/noteid}
	for(i in `{grep -l $g /proc/*/noteid | sed 's:/proc/([^/]+)/noteid:\1:g'=
})
		if(test -d /proc/$i)
			echo $i
}

fn reaper{
	nbroken=3D()
	for(i in `{ps | awk '$6 =3D=3D "Broken" && $7 =3D=3D "dns" {print $2}'})=
{
		r =3D /n/other/$user/dnssnap/$sysname.$i.`{date -n}
		snap -o $r `{pgroup $i}
		nbroken =3D ($nbroken $r)
	}
}

fn getips{
	ndb/dnsquery $* | sed 's/.*[ 	]//g'
}

fn google{
	google=3D()
	if(! ip/cidr -rf <{getips google.com} <{echo $gcidr})
		google=3D1
	if(ip/cidr -f /lib/badcidr <{getips 9fans.net} )
		google=3D($google 2)
}

fn why{
	if(! ~ $#nbroken 0){
		echo getting medi=C3=A6val on $#nbroken broken dns processes.
		for(i in $nbroken)
			echo $i
	}
	if(! ~ $#nwait 0){
		echo getting medi=C3=A6val on $#nwait deadlocked dns processes.
		for(i in $nwait)
			echo $i
	}
	if(! ~ $#google 0){
		echo google broken
		ndb/dnsquery google.com
		ndb/dnsquery 9fans.net any
	}
}

flagfmt=3D'p,f'
args=3D()
if(! ifs=3D() eval `{aux/getflags $*} || ! ~ $#* 0){
	aux/usage
	exit usage
}

if(~ $#flagf 0){
	if(! ~ $sysname $allow)
		exit 'wrong system'
	reaper
	ifs=3D$nl nwait=3D`{ps -a |sed -n 's/.* +dns \[query lock wait for(.*)\]=
/\1/gp' | sort | uniq -c | awk '$1>2'}
	google

	if(~ $#nbroken 0 && ~ $#nwait 0 && ~ $#google 0)
		exit 'none broken'
	why
	if(~ $service rx)
		{date; echo; why; echo; ps -a | grep ' dns ' }| mail -s 'restartdns: '^=
$sysname $mailto
}

if(~ $flagp 1)
	exit ''

syslog slaying broken $#nbroken nwait $#nwait google $#google

dns =3D ndb/dns
slaydns =3D `{echo $dns | sed 's:.*/::g'}
slay $slaydns | rc
unmount '#s/dns' /net/dns >[2=3D]
unmount '#s/dns_net.alt' /net.alt/dns >[2=3D]
rm -f '#s/dns'  '#s/dns_net.alt'

$dns -N 20000 -s
if(~ $sysname $recursive)
	$dns -sx /net.alt -f /lib/ndb/external
if not
	$dns -Rrsx /net.alt -f /lib/ndb/external
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