#!/usr/bin/ruby

# This script generates a djbdns tinydns data file, with ipv6 support
# You still need an ipv6 patch for tcpserver if you want to handle queries over ipv6

# Yoann Guillot, 04/2007, license: wtfpl

# some variables for frequently-used ips
intip = '192.168.7.1'
extip = '82.227.12.18'
extip6 = '2002:%x%02x:%x%02x::1' % extip.split('.')	# 6to4 address

#
# public
#

nsname = 'a.ns.ofjj.net'		# the machine hosting the server
ns   'ofjj.net', nsname			# authoritative forward
ns   arpa6(extip6, 12), nsname		# authoritative for reverse ipv6 (check 6to4.nro.net)
a    nsname, extip
aaaa nsname, extip6			# ensure tinydns listens on ipv6

mxname = 'a.mx.ofjj.net'		# mx entry
mx   'ofjj.net', mxname
a    mxname, extip
aaaa mxname, extip6			# ensure your smtp listens on ipv6

# the last non-arpa ns zone is used as default suffix for non-'.' names
host 'thebox', extip		# machine definitions
host6 'thebox', extip6
a 'ofjj.net', extip
aaaa 'ofjj.net', extip6
a 'vpn', extip

a 'ipv4', extip
aaaa 'ipv6', extip6


#
# internal
#

localto('192.168.7', '127') {
insname = 'a.ns.jj'
ns   'jj', insname
ns   arpa(intip, 3), insname
a    insname, intip

host 'jjbox', intip
host 'station', '192.168.7.12'
a 'www', intip
}



# write text file
Dir.chdir '/service/tinydns/root'
File.open('data.new', 'w') { |fd|
	fd.puts $data.map { |l| l.join(':') }
	fd.fsync
}
File.rename('data.new', 'data')
system 'tinydns-data'			# create db file

# restart cache server (TODO find a way to just flush its cache)
system 'svc -t /service/dnscache'

puts 'done'


BEGIN {
	# this holds the data to be written to the file
	$data = []
	# default suffix for hostnames without a '.' -- set by ns()
	$suffix = ''
	# default client location specification (for split views) -- use with localto() { }
	$lo = nil

	# client-specific configuration (aka 'views')
	# longest prefix takes precedence
	# non-localto definitions are global
	# ex: localto('192.168', '127') { host 'foo.com', '192.168.0.1' } ; localto { host 'foo.com', '1.2.3.4' }
	# works by temporarily rewriting $lo (prefixes are cached, so you may safely use multiple blocks with same prefix)
	def localto(*prefixes)
	    prefixes << '' if prefixes.empty?
	    prefixes.each { |prefix|
		# generate new prefix
		$lomap ||= {}
		if not mylo = $lomap.index(prefix)
			if $lomap.empty?
				mylo = 'aa'
			else
				mylo = $lomap.keys.last.succ	# 'aa' => 'ab', 'az' => 'ba'
			end
			$lomap[mylo] = prefix
			# the prefix is new, tell tinydns about it
			$data << ['%'+mylo, prefix]
		end
		oldlo, $lo = $lo, mylo

		yield

		$lo = oldlo
	    }
	end

	def expandip6(ip)
		# 0102:f::3 => [1, 2, 0, 15, <0..>, 3]
		ip = '0'+ip if ip[0] == ?:
		ip = ip+'0' if ip[-1] == ?:
		ip = ip.split(':')
		ip[ip.index(''), 1] = ['0'] * (9 - ip.length) if ip.index('')	# expand '::'
		ip.map { |d| d = d.hex ; [d >> 8, d & 255] }.flatten
	end
	def arpa(ip, len=4)
		ip.split('.')[0, len].reverse.join('.') + '.in-addr.arpa'
	end
	def arpa6(ip, len=32)
		expandip6(ip).map { |d| [d >> 4, d & 15] }.flatten[0, len].reverse.map { |e| e.to_s 16 }.join('.') + '.ip6.arpa'
	end

	# append suffix if no '.'
	def s(name) name.include?(?.) ? name : name+$suffix end
	def generic(fqdn, type, data, ttl=nil, ts=nil, lo=$lo)    $data << [':'+fqdn, type, data, ttl, ts, lo] end
	def ns(zone, dns='a', dnsip='', ttl=nil, ts=nil, lo=$lo)
		$suffix = '.'+zone if zone !~ /\.arpa$/i
		$data << ['.'+zone, dnsip, dns, ttl, ts, lo]
	end
	def childns(zone, dns='a', dnsip='', ttl=nil, ts=nil, lo=$lo)  $data << ['&'+zone, dnsip, dns, ttl, ts, lo] end
	def host(fqdn, ip, ttl=nil, ts=nil, lo=$lo)               $data << ['='+s(fqdn), ip, ttl, ts, lo] end
	def mx(fqdn, ip, mx='a', dist=0, ttl=nil, ts=nil, lo=$lo) $data << ['@'+s(fqdn), ip, mx, dist, ttl, ts, lo] end
	def a(fqdn, ip, ttl=nil, ts=nil, lo=$lo)                  $data << ['+'+s(fqdn), ip, ttl, ts, lo] end
	def ptr(fqdn, name, ttl=nil, ts=nil, lo=$lo)              $data << ['^'+fqdn, s(name), ttl, ts, lo] end
	def aaaa(fqdn, ip, ttl=nil, ts=nil, lo=$lo)
		data = expandip6(ip).map { |d| '\\%03o' % d }.join
		generic(s(fqdn), 28, data, ttl, ts, lo)
	end
	def host6(fqdn, ip, ttl=nil, ts=nil, lo=$lo)
		aaaa s(fqdn), ip, ttl, ts, lo
		ptr  arpa6(ip), s(fqdn), ttl, ts, lo
	end
}