/lib/rex/socket/udp.rb

# -*- coding: binary -*-
require 'rex/socket'

###
#
# This class provides methods for interacting with a UDP socket.
#
###
module Rex::Socket::Udp

	include Rex::Socket

	##
	#
	# Factory
	#
	##

	#
	# Creates the client using the supplied hash.
	#
	def self.create(hash = {})
		hash['Proto'] = 'udp'
		# If we have are to bind to a LocalHost we must be a Server to avail of pivoting.
		# Rex::Socket::Parameters will subsequently turn off the sever flag after the correct
		# comm has been chosen.
		if( hash['LocalHost'] )
			hash['Server'] = true
		end
		self.create_param(Rex::Socket::Parameters.from_hash(hash))
	end

	#
	# Wrapper around the base socket class' creation method that automatically
	# sets the parameter's protocol to UDP.
	#
	def self.create_param(param)
		param.proto = 'udp'
		Rex::Socket.create_param(param)
	end

	##
	#
	# UDP connected state methods
	#
	##

	#
	# Write the supplied datagram to the connected UDP socket.
	#
	def write(gram)
		begin
			return syswrite(gram)
		rescue  ::Errno::EHOSTUNREACH,::Errno::ENETDOWN,::Errno::ENETUNREACH,::Errno::ENETRESET,::Errno::EHOSTDOWN,::Errno::EACCES,::Errno::EINVAL,::Errno::EADDRNOTAVAIL
			return nil
		end
	end

	alias put write

	#
	# Read a datagram from the UDP socket.
	#
	def read(length = 65535)
		if length < 0
			length = 65535
		end
		return sysread(length)
	end

	#
	# Read a datagram from the UDP socket with a timeout
	#
	def timed_read(length = 65535, timeout=def_read_timeout)
		begin
			if ((rv = ::IO.select([ fd ], nil, nil, timeout)) and
			    (rv[0]) and (rv[0][0] == fd)
			   )
					return read(length)
			else
				return ''
			end
		rescue Exception
			return ''
		end
	end

	#alias send write
	#alias recv read

	##
	#
	# UDP non-connected state methods
	#
	##

	#
	# Sends a datagram to the supplied host:port with optional flags.
	#
	def sendto(gram, peerhost, peerport, flags = 0)

		# Catch unconnected IPv6 sockets talking to IPv4 addresses
		peer = Rex::Socket.resolv_nbo(peerhost)
		if (peer.length == 4 and self.ipv == 6)
			peerhost = Rex::Socket.getaddress(peerhost, true)
			if peerhost[0,7].downcase != '::ffff:'
				peerhost = '::ffff:' + peerhost
			end
		end

		begin
			send(gram, flags, Rex::Socket.to_sockaddr(peerhost, peerport))
		rescue  ::Errno::EHOSTUNREACH,::Errno::ENETDOWN,::Errno::ENETUNREACH,::Errno::ENETRESET,::Errno::EHOSTDOWN,::Errno::EACCES,::Errno::EINVAL,::Errno::EADDRNOTAVAIL
			return nil
		end

	end

	#
	# Receives a datagram and returns the data and host:port of the requestor
	# as [ data, host, port ].
	#
	def recvfrom(length = 65535, timeout=def_read_timeout)

		begin
			if ((rv = ::IO.select([ fd ], nil, nil, timeout)) and
			    (rv[0]) and (rv[0][0] == fd)
			   )
					data, saddr    = recvfrom_nonblock(length)
					af, host, port = Rex::Socket.from_sockaddr(saddr)

					return [ data, host, port ]
			else
				return [ '', nil, nil ]
			end
		rescue ::Timeout::Error
			return [ '', nil, nil ]
		rescue ::Interrupt
			raise $!
		rescue ::Exception
			return [ '', nil, nil ]
		end
	end

	#
	# Calls recvfrom and only returns the data
	#
	def get(timeout=nil)
		data, saddr, sport = recvfrom(65535, timeout)
		return data
	end

	#
	# The default number of seconds to wait for a read operation to timeout.
	#
	def def_read_timeout
		10
	end

	def type?
		return 'udp'
	end

end