XDR-fu j0!

git-svn-id: file:///home/svn/incoming/trunk@2331 4d416f70-5f16-0410-b530-b9f4589650da

lib/rex/proto/rpc/xdr.rb

@@ -0,0 +1,102 @@
+module Rex
+
+class XDR
+	MAX_ARG = 0xffffffff
+	private_class_method :new
+	
+# Also: unsigned int, bool, enum
+	def XDR.encode_int(int)
+		return [int].pack('N')
+	end
+	
+	def XDR.decode_int!(data)
+		return data.slice!(0..3).unpack('N')[0]
+	end
+	
+	
+	def XDR.encode_lchar(char)
+		char |= 0xffffff00 if char & 0x80 != 0
+		return encode_int(char)
+	end
+	
+	def XDR.decode_lchar!(data)
+		return (decode_int!(data) & 0xff).chr
+	end
+	
+	
+# Also: Variable length opaque
+	def XDR.encode_string(str, max=MAX_ARG)
+		raise ArgumentError, 'XDR: String too long' if str.length > max
+		len = str.length
+		str += "\x00" * ((4 - (len & 3)) & 3)
+		return encode_int(len) + str
+	end
+	
+	def XDR.decode_string!(data)
+		real_len = decode_int!(data)
+		return "" if real_len == 0
+		align_len = (real_len + 3) & ~3
+		return data.slice!(0..align_len-1).slice(0..real_len-1)
+	end
+	
+	
+	def XDR.encode_varray(arr, max=MAX_ARG, &block)
+		raise ArgumentError, 'XDR: Too many array elements' if arr.length > max
+		return encode_int(arr.length) + arr.collect(&block).join(nil)
+	end
+	
+	def XDR.decode_varray!(data)
+		buf = []
+		1.upto(decode_int!(data)) { buf.push(yield(data)) }
+		return buf
+	end
+	
+	
+	
+# encode(0, [0, 1], "foo", ["bar", 4]) does:
+# encode_int(0) + encode_varray([0, 1]) { |i| XDR.encode_int(i) } +
+#   encode_string("foo") + encode_string("bar, 4)
+	def XDR.encode(*data)
+		data.collect do |var|
+			if var.kind_of?(String)
+				encode_string(var)
+			elsif var.kind_of?(Integer)
+				encode_int(var)
+			elsif var.kind_of?(Array) && var[0].kind_of?(String)
+				raise ArgumentError, 'XDR: Incorrect string array arguments' if var.length != 2
+				encode_string(var[0], var[1])
+			elsif var.kind_of?(Array) && var[0].kind_of?(Integer)
+				encode_varray(var) { |i| XDR.encode_int(i) }
+# 0 means an empty array index in the case of Integer and an empty string in
+#   the case of String so we get the best of both worlds
+			elsif var.kind_of?(Array) && var[0].nil?
+				encode_int(0)
+			else
+				type = var.class
+				type = var[0].class if var.kind_of?(Array)
+				raise TypeError, "XDR: encode does not support #{type}"
+			end
+		end.join(nil)
+	end
+
+# decode(buf, Integer, String, [Integer], [String]) does:
+# [decode_int!(buf), decode_string!(buf),
+#   decode_varray!(buf) { |i| XDR.decode_int!(i) },
+#   decode_varray!(buf) { |s| XDR.decode_string(s) }]
+	def XDR.decode!(buf, *data)
+		return *data.collect do |var|
+			if data.length == 0
+			elsif var.kind_of?(Array) && var[0] == String
+				decode_varray!(buf) { |s| XDR.decode_string!(s) }
+			elsif var.kind_of?(Array) && var[0] == Integer
+				decode_varray!(buf) { |i| XDR.decode_int!(i) }
+			elsif var == String
+				decode_string!(buf)
+			elsif var == Integer
+				decode_int!(buf)
+			end
+		end
+	end
+end
+
+end