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require "resolv"
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require "timeout"
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module Net
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module DNS
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autoload :ARecord, "net/dns/a_record.rb"
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autoload :PTRRecord, "net/dns/ptr_record.rb"
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# Looks up the IP or MAC address. Handles the conversion of a DNS miss
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# exception into nil
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# [+query+]: IP or hostname
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# Returns: a new DNS record object, A or PTR accordingly
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# We query DNS directly, as its faster then to query our own proxy.
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def self.lookup(query, proxy, resolver = Resolv::DNS.new)
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Timeout::timeout(Setting[:dns_conflict_timeout]) do
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if (query =~ Validations::IP_REGEXP)
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n = resolver.getname(query).to_s
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i = query
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t = "PTR"
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else
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i = resolver.getaddress(query).to_s
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n = query
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t = "A"
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end
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attrs = { :hostname => n, :ip => i, :resolver => resolver, :proxy => proxy }
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case t
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when "A"
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ARecord.new attrs
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when "PTR"
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PTRRecord.new attrs
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end
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end
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rescue Resolv::ResolvError, SocketError
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nil
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rescue Timeout::Error => e
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raise Net::Error, e
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end
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class Record < Net::Record
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attr_accessor :ip, :resolver, :type
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def initialize(opts = { })
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super(opts)
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self.ip = validate_ip self.ip
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self.resolver ||= Resolv::DNS.new
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end
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def destroy
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logger.info "Delete the DNS #{type} record for #{self}"
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end
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def create
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raise "Must define a hostname" if hostname.blank?
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logger.info "Add DNS #{type} record for #{self}"
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end
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def attrs
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raise "Abstract class"
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end
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def dns_lookup(ip_or_name)
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DNS.lookup(ip_or_name, proxy, resolver)
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end
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protected
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def generate_conflict_error
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logger.warn "Conflicting DNS #{type} record for #{self} detected"
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e = Net::Conflict.new
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e.type = "dns"
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e.expected = to_s
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e.actual = conflicts
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e.message = "DNS conflict detected - expected #{self}, found #{conflicts.map(&:to_s).join(', ')}"
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e
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end
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end
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end
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end
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