mirror of https://github.com/cmur2/dyndnsd.git
updater: add zone_transfer_server updater
parent
8976ff5bbe
commit
3a9c2d65fb
@ -0,0 +1,158 @@
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# frozen_string_literal: true
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require 'resolv'
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require 'securerandom'
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require 'async/dns'
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module Dyndnsd
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module Updater
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class ZoneTransferServer
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DEFAULT_SERVER_LISTENS = ['0.0.0.0@53'].freeze
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# @param domain [String]
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# @param updater_params [Hash{String => Object}]
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def initialize(domain, updater_params)
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@domain = domain
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@server_listens = self.class.parse_endpoints(updater_params['server_listens'] || DEFAULT_SERVER_LISTENS)
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@notify_targets = (updater_params['send_notifies'] || []).map { |e| self.class.parse_endpoints([e]) }
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@zone_rr_ttl = updater_params['zone_ttl']
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@zone_nameservers = updater_params['zone_nameservers'].map { |n| Resolv::DNS::Name.create(n) }
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@zone_email_address = Resolv::DNS::Name.create(updater_params['zone_email_address'])
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@zone_additional_ips = updater_params['zone_additional_ips'] || []
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@server = ZoneTransferServerHelper.new(@server_listens, @domain)
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# run Async::DNS server in background thread
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Thread.new do
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@server.run
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end
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end
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# @param db [Dyndnsd::Database]
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# @return [void]
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def update(db)
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Helper.span('updater_update') do |span|
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span.set_tag('dyndnsd.updater.name', self.class.name&.split('::')&.last || 'None')
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soa_rr = Resolv::DNS::Resource::IN::SOA.new(
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@zone_nameservers[0], @zone_email_address,
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db['serial'],
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10_800, # 3h
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300, # 5m
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604_800, # 1w
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3_600 # 1h
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)
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default_options = {ttl: @zone_rr_ttl}
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# array containing all resource records for an AXFR request in the right order
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rrs = []
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# AXFR responses need to start with zone's SOA RR
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rrs << [soa_rr, default_options]
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# return RRs for all of the zone's nameservers
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@zone_nameservers.each do |ns|
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rrs << [Resolv::DNS::Resource::IN::NS.new(ns), default_options]
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end
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# return A/AAAA RRs for all additional IPv4s/IPv6s for the domain itself
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@zone_additional_ips.each do |ip|
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rrs << [create_addr_rr_for_ip(ip), default_options]
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end
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# return A/AAAA RRs for the dyndns hostnames
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db['hosts'].each do |hostname, ips|
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ips.each do |ip|
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rrs << [create_addr_rr_for_ip(ip), default_options.merge({name: hostname})]
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end
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end
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# AXFR responses need to end with zone's SOA RR again
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rrs << [soa_rr, default_options]
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# point Async::DNS server thread's variable to this new RR array
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@server.axfr_rrs = rrs
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# only send DNS NOTIFY if there really was a change
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if db.changed?
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send_dns_notify
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end
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end
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end
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# converts into suitable parameter form for Async::DNS::Resolver or Async::DNS::Server
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#
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# @param endpoint_list [Array{String}]
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# @return [Array{Array{Object}}]
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def self.parse_endpoints(endpoint_list)
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endpoint_list.map { |addr_string| addr_string.split('@') }
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.map { |addr_parts| [addr_parts[0], addr_parts[1].to_i || 53] }
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.map { |addr| [:tcp, :udp].map { |type| [type] + addr } }
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.flatten(1)
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end
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private
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# creates correct Resolv::DNS::Resource object for IP address type
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#
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# @param ip_string [String]
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# @return [Resolv::DNS::Resource::IN::A,Resolv::DNS::Resource::IN::AAAA]
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def create_addr_rr_for_ip(ip_string)
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ip = IPAddr.new(ip_string).native
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if ip.ipv6?
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Resolv::DNS::Resource::IN::AAAA.new(ip.to_s)
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else
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Resolv::DNS::Resource::IN::A.new(ip.to_s)
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end
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end
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# https://tools.ietf.org/html/rfc1996
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#
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# @return [void]
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def send_dns_notify
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Async::Reactor.run do
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@notify_targets.each do |notify_target|
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target = Async::DNS::Resolver.new(notify_target)
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# assemble DNS NOTIFY message
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request = Resolv::DNS::Message.new(SecureRandom.random_number(2**16))
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request.opcode = Resolv::DNS::OpCode::Notify
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request.add_question("#{@domain}.", Resolv::DNS::Resource::IN::SOA)
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_response = target.dispatch_request(request)
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end
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end
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end
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end
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class ZoneTransferServerHelper < Async::DNS::Server
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attr_accessor :axfr_rrs
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def initialize(endpoints, domain)
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super(endpoints, logger: Dyndnsd.logger)
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@domain = domain
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end
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# @param name [String]
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# @param resource_class [Resolv::DNS::Resource]
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# @param transaction [Async::DNS::Transaction]
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# @return [void]
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def process(name, resource_class, transaction)
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if name != @domain || resource_class != Resolv::DNS::Resource::Generic::Type252_Class1
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transaction.fail!(:NXDomain)
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return
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end
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# https://tools.ietf.org/html/rfc5936
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transaction.append_question!
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@axfr_rrs.each do |rr|
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transaction.add([rr[0]], rr[1])
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end
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end
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end
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end
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end
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