Fiat lux

lib/dyndnsd.rb

@@ -0,0 +1,127 @@
+#!/usr/bin/env ruby
+
+require 'logger'
+require 'ipaddr'
+require 'json'
+require 'yaml'
+require 'rack'
+
+require 'dyndnsd/generator/bind'
+require 'dyndnsd/updater/command_with_bind_zone'
+require 'dyndnsd/responder/rest_style'
+require 'dyndnsd/database'
+require 'dyndnsd/version'
+
+module Dyndnsd
+  def self.logger
+    @logger
+  end
+
+  def self.logger=(logger)
+    @logger = logger
+  end
+
+  class LogFormatter
+    def call(lvl, time, progname, msg)
+      "%s: %s\n" % [lvl, msg.to_s]
+    end
+  end
+
+  class Daemon
+    def initialize(config, db, updater, responder)
+      @users = config['users']
+      @db = db
+      @updater = updater
+      @responder = responder
+
+      @db.load
+      @db['serial'] ||= 1
+      @db['hosts'] ||= {}
+      (@db.save; update) if @db.changed?
+    end
+    
+    def update
+      @updater.update(@db)
+    end
+    
+    def call(env)
+      return @responder.response_for(:method_forbidden) if env["REQUEST_METHOD"] != "GET"
+      return @responder.response_for(:not_found) if env["PATH_INFO"] != "/nic/update"
+      
+      params = Rack::Utils.parse_query(env["QUERY_STRING"])
+      
+      return @responder.response_for(:hostname_missing) if not params["hostname"]
+      
+      hostname = params["hostname"]
+      
+      # Check if hostname(s) match rules
+      #return @responder.response_for(:hostname_malformed) if XY
+      
+      user = env["REMOTE_USER"]
+      
+      return @responder.response_for(:host_forbidden) if not @users[user]['hosts'].include? hostname
+      
+      # no myip?
+      if not params["myip"]
+        params["myip"] = env["REMOTE_ADDR"]
+      end
+      
+      # malformed myip?
+      begin
+        IPAddr.new(params["myip"], Socket::AF_INET)
+      rescue ArgumentError
+        params["myip"] = env["REMOTE_ADDR"]
+      end
+      
+      myip = params["myip"]
+      
+      @db['hosts'][hostname] = myip    
+      
+      if @db.changed?
+        @db['serial'] += 1
+        @db.save
+        update
+        return @responder.response_for(:good)
+      end
+      
+      @responder.response_for(:nochg)
+    end
+
+    def self.run!
+      Dyndnsd.logger = Logger.new(STDOUT)
+      Dyndnsd.logger.formatter = LogFormatter.new
+
+      if ARGV.length != 1
+        puts "Usage: dyndnsd config_file"
+        exit 1
+      end
+
+      config_file = ARGV[0]
+
+      if not File.file?(config_file)
+        Dyndnsd.logger.fatal "Config file not found!"
+        exit 1
+      end
+
+      Dyndnsd.logger.info "DynDNSd version #{Dyndnsd::VERSION}"
+      Dyndnsd.logger.info "Using config file #{config_file}"
+
+      config = YAML::load(File.open(config_file, 'r') { |f| f.read })
+
+      db = Database.new(config['db_file'])
+      updater = Updater::CommandWithBindZone.new(config['updater_params']) if config['updater'] == 'command_with_bind_zone'
+      responder = Responder::RestStyle.new
+      
+      app = Daemon.new(config, db, updater, responder)
+      app = Rack::Auth::Basic.new(app, "DynDNS") do |user,pass|
+        (config['users'].has_key? user) and (config['users'][user]['password'] == pass)
+      end
+
+      Signal.trap('INT') do
+        Rack::Handler::WEBrick.shutdown
+      end
+
+      Rack::Handler::WEBrick.run app, :Host => config['host'], :Port => config['port']
+    end
+  end
+end

lib/dyndnsd/database.rb

@@ -0,0 +1,32 @@
+
+require 'forwardable'
+
+module Dyndnsd
+  class Database
+    extend Forwardable
+    
+    def_delegators :@db, :[], :[]=, :each, :has_key?
+  
+    def initialize(db_file)
+      @db_file = db_file
+    end
+    
+    def load
+      if File.file?(@db_file)
+        @db = JSON.load(File.open(@db_file, 'r') { |f| f.read })
+      else
+        @db = {}
+      end
+      @db_hash = @db.hash
+    end
+    
+    def save
+      File.open(@db_file, 'w') { |f| JSON.dump(@db, f) }
+      @db_hash = @db.hash
+    end
+    
+    def changed?
+      @db_hash != @db.hash
+    end
+  end
+end

lib/dyndnsd/generator/bind.rb

@@ -0,0 +1,29 @@
+
+module Dyndnsd
+  module Generator
+    class Bind
+      def initialize(config)
+        @ttl = config['ttl']
+        @origin = config['origin']
+        @dns = config['dns']
+        @email_addr = config['email_addr']
+      end
+
+      def generate(zone)
+        out = []
+        out << "$TTL #{@ttl}"
+        out << "$ORIGIN #{@origin}"
+        out << ""
+        out << "@ IN SOA #{@dns} #{@email_addr} ( #{zone['serial']} 3h 5m 1w 1h )"
+        out << "@ IN NS #{@dns}"
+        out << ""
+        zone['hosts'].each do |hostname,ip|
+          name = hostname.chomp('.' + @origin[0..-2])
+          out << "#{name} IN A #{ip}"
+        end
+        out << ""
+        out.join("\n")
+      end
+    end
+  end
+end

lib/dyndnsd/responder/rest_style.rb

@@ -0,0 +1,19 @@
+
+module Dyndnsd
+  module Responder
+    class RestStyle
+      def response_for(state)
+        # general http errors
+        return [405, {"Content-Type" => "text/plain"}, ["Method Not Allowed"]] if state == :method_forbidden
+        return [404, {"Content-Type" => "text/plain"}, ["Not Found"]] if state == :not_found
+        # specific errors
+        return [422, {"Content-Type" => "text/plain"}, ["Hostname missing"]] if state == :hostname_missing
+        return [403, {"Content-Type" => "text/plain"}, ["Forbidden"]] if state == :host_forbidden
+        return [422, {"Content-Type" => "text/plain"}, ["Hostname malformed"]] if state == :hostname_malformed
+        # OKs
+        return [200, {"Content-Type" => "text/plain"}, ["Good"]] if state == :good
+        return [200, {"Content-Type" => "text/plain"}, ["No change"]] if state == :nochg
+      end
+    end
+  end
+end

lib/dyndnsd/updater/command_with_bind_zone.rb

@@ -0,0 +1,21 @@
+
+module Dyndnsd
+  module Updater
+    class CommandWithBindZone
+      def initialize(config)
+        @zone_file = config['zone_file']
+        @command = config['command']
+        @generator = Generator::Bind.new(config)
+      end
+      
+      def update(zone)
+        # write zone file in bind syntax
+        File.open(@zone_file, 'w') { |f| f.write(@generator.generate(zone)) }
+        # call user-defined command
+        pid = fork do
+          exec @command
+        end
+      end
+    end
+  end
+end

lib/dyndnsd/version.rb

@@ -0,0 +1,4 @@
+
+module Dyndnsd
+  VERSION = "0.0.1"
+end