#!/usr/bin/ruby

require 'socket'
require 'rex/post/meterpreter/client_core'
require 'rex/post/meterpreter/channel'
require 'rex/post/meterpreter/channel_container'
require 'rex/post/meterpreter/dependencies'
require 'rex/post/meterpreter/object_aliases'
require 'rex/post/meterpreter/packet'
require 'rex/post/meterpreter/packet_parser'
require 'rex/post/meterpreter/packet_dispatcher'

module Rex
module Post
module Meterpreter

#
# Just to get it in there...
#
module Extensions
end

###
#
# This class represents a logical meterpreter client class.  This class
# provides an interface that is compatible with the Rex post-exploitation
# interface in terms of the feature set that it attempts to expose.  This
# class is meant to drive a single meterpreter client session.
#
###
class Client

	include Rex::Post::Meterpreter::PacketDispatcher
	include Rex::Post::Meterpreter::ChannelContainer

	#
	# Initializes the client context with the supplied socket through
	# which communication with the server will be performed.
	#
	def initialize(sock, to = self.class.default_timeout)
		init_meterpreter(sock, to)
	end

	#
	# Initializes the meterpreter client instance
	#
	def init_meterpreter(sock, to = self.class.default_timeout)
		self.sock        = sock
		self.parser      = PacketParser.new
		self.ext         = ObjectAliases.new
		self.ext_aliases = ObjectAliases.new

		self.response_timeout = to

		register_extension_alias('core', ClientCore.new(self))

		initialize_inbound_handlers
		initialize_channels

		# Register the channel inbound packet handler
		register_inbound_handler(Rex::Post::Meterpreter::Channel)

		monitor_socket
	end

	##
	# 
	# Accessors
	#
	##

	#
	# Returns the default timeout that request packets will use when
	# waiting for a response.
	#
	def Client.default_timeout
		return 30
	end

	##
	#
	# Alias processor
	#
	##

	#
	# Translates unhandled methods into registered extension aliases
	# if a matching extension alias exists for the supplied symbol.
	#
	def method_missing(symbol, *args)
		return self.ext_aliases.aliases[symbol.to_s];
	end

	##
	#
	# Extension registration
	#
	##

	#
	# Loads the client half of the supplied extension and initializes it as a
	# registered extension that can be reached through client.ext.[extension].
	#
	def add_extension(name)
		old = Rex::Post::Meterpreter::Extensions.constants
		require("rex/post/meterpreter/extensions/#{name.downcase}/#{name.downcase}")
		new = Rex::Post::Meterpreter::Extensions.constants

		# No new constants added?
		if ((diff = new - old).empty?)
			return false
		end

		# XXX might want to be safer and catch the exception here?
		# maybe not since we are just going to reraise right away...
		ext = Rex::Post::Meterpreter::Extensions.const_get(diff[0]).const_get(diff[0]).new(self)

		self.ext.aliases[ext.name] = ext

		return true
	end

	#
	# Deregisters an extension alias of the supplied name.
	#
	def deregister_extension(name)
		self.ext.aliases.delete(name)
	end

	#
	# Enumerates all of the loaded extensions.
	#
	def each_extension(&block)
		self.ext.aliases.each(block)
	end

	#
	# Registers an aliased extension that can be referenced through
	# client.name.
	#
	def register_extension_alias(name, ext)
		self.ext_aliases.aliases[name] = ext
	end

	#
	# Registers zero or more aliases that are provided in an array.
	#
	def register_extension_aliases(aliases)
		aliases.each { |a|
			register_extension_alias(a['name'], a['ext'])
		}
	end

	#
	# Deregisters a previously registered extension alias.
	#
	def deregister_extension_alias(name)
		self.ext_aliases.aliases.delete(name)
	end

	#
	# Dumps the extension tree.
	#
	def dump_extension_tree()
		items = []
		items.concat(self.ext.dump_alias_tree('client.ext'))
		items.concat(self.ext_aliases.dump_alias_tree('client'))

		return items.sort
	end

	#
	# The extension alias under which all extensions can be accessed by name.
	# For example:
	#
	#    client.ext.stdapi
	#
	#
	attr_reader   :ext
	#
	# The socket the client is communicating over.
	#
	attr_reader   :sock
	#
	# The timeout value to use when waiting for responses.
	#
	attr_accessor :response_timeout
protected
	attr_accessor :parser, :ext_aliases # :nodoc:
	attr_writer   :ext, :sock # :nodoc:
end

end; end; end