Add packet padding container for packet length shaping

common/packetPaddingContainer/containerIfce.go

@@ -0,0 +1,34 @@
+package packetPaddingContainer
+
+// PacketPaddingContainer is an interface that defines methods to pad packets
+// with a given number of bytes, and to unpack the padding from a padded packet.
+// The packet format is as follows if the desired output length is greater than
+// 2 bytes:
+// | data | padding | data length |
+// The data length is a 16-bit big-endian integer that represents the length of
+// the data in bytes.
+// If the desired output length is 2 bytes or less, the packet format is as
+// follows:
+// | padding |
+// No payload will be included in the packet.
+type PacketPaddingContainer interface {
+	// Pack pads the given data with the given number of bytes, and appends the
+	// length of the data to the end of the data. The returned byte slice
+	// contains the padded data.
+	// This generates a packet with a length of
+	// len(data_OWNERSHIP_RELINQUISHED) + padding + 2
+	// @param data_OWNERSHIP_RELINQUISHED - The payload, this reference is consumed and should not be used after this call.
+	// @param padding - The number of padding bytes to add to the data.
+	Pack(data_OWNERSHIP_RELINQUISHED []byte, padding int) []byte
+
+	// Unpack extracts the data and padding from the given padded data. It
+	// returns the data and the number of padding bytes.
+	// the data may be nil.
+	// @param wrappedData_OWNERSHIP_RELINQUISHED - The packet, this reference is consumed and should not be used after this call.
+	Unpack(wrappedData_OWNERSHIP_RELINQUISHED []byte) ([]byte, int)
+
+	// Pad returns a padding packet of padding length.
+	// If the padding length is less than 0, nil is returned.
+	// @param padding - The number of padding bytes to add to the data.
+	Pad(padding int) []byte
+}