Method RoutineEncryption

polyamide/device/send.go:403–439

* Encrypts the elements in the queue * and marks them for sequential consumption (by releasing the mutex) * * Obs. One instance per core */

(id int)

 * Obs. One instance per core
 */
func (device *Device) RoutineEncryption(id int) {
	var paddingZeros [PaddingMultiple]byte
	var nonce [chacha20poly1305.NonceSize]byte

	defer device.Log.Verbosef("Routine: encryption worker %d - stopped", id)
	device.Log.Verbosef("Routine: encryption worker %d - started", id)

	for elemsContainer := range device.queue.encryption.c {
		for _, elem := range elemsContainer.elems {
			// populate header fields
			header := elem.buffer[:MessageTransportHeaderSize]

			fieldType := header[0:4]
			fieldReceiver := header[4:8]
			fieldNonce := header[8:16]

			binary.LittleEndian.PutUint32(fieldType, MessageTransportType)
			binary.LittleEndian.PutUint32(fieldReceiver, elem.keypair.remoteIndex)
			binary.LittleEndian.PutUint64(fieldNonce, elem.nonce)

			// pad content to multiple of 16
			paddingSize := calculatePaddingSize(len(elem.packet), int(device.tun.mtu.Load()))
			elem.packet = append(elem.packet, paddingZeros[:paddingSize]...)

			// encrypt content and release to consumer

			binary.LittleEndian.PutUint64(nonce[4:], elem.nonce)
			elem.packet = elem.keypair.send.Seal(
				header,
				nonce[:],
				elem.packet,
				nil,
			)
		}
		elemsContainer.Unlock()
	}
}

/*
This function arranges buffers and endpoints by endpoint, into contiguous