#!/usr/bin/env python3 # -*- coding: utf-8 -*- """ Created on Sun Dec 27 20:43:40 2020 @author: DJ2LS """ # CRC aller payloads via XOR scrambeln und dann eine CRC8 mitsenden import logging import crcengine import threading import time import static import modem import other modem = modem.RF() crc_algorithm = crcengine.new('crc16-ccitt-false') #load crc16 library static.ARQ_PAYLOAD_PER_FRAME = static.FREEDV_PAYLOAD_PER_FRAME - 6 def data_received(data_in): ARQ_N_RX_BURSTS = int.from_bytes(bytes(data_in[:1]), "big") - 10 static.ARQ_RX_BURST_BUFFER.append(data_in) #append data to RX BUFFER #print(ARQ_N_RX_BURSTS) burst_total_payload = bytearray() #while static.ACK_RX_TIMEOUT == 0: #define timeout where data has to be received untl error occurs if len(static.ARQ_RX_BURST_BUFFER) == ARQ_N_RX_BURSTS: #if received bursts are equal to burst number in frame #burst_total_payload = bytearray() for n_raw_frame in range(0,len(static.ARQ_RX_BURST_BUFFER)): burst_frame = static.ARQ_RX_BURST_BUFFER[n_raw_frame] #get burst frame burst_payload = burst_frame[3:] #remove frame type and burst CRC burst_total_payload = burst_total_payload + burst_payload #stick bursts together # ------------------ caculate CRC of BURST #print(burst_total_payload) burst_payload_crc = crc_algorithm(burst_total_payload) burst_payload_crc = burst_payload_crc.to_bytes(2, byteorder='big') #print(burst_payload_crc) # IF BURST CRC IS CORRECT, APPEND BURST TO BUFFER AND SEND ACK FRAME if burst_payload_crc == data_in[1:3]: logging.info("BURST CRC ARE EQUAL!") logging.info("TX | SENDING ARQ BURST ACK [" + str(data_in[1:3]) +"]") print(burst_total_payload) static.ARQ_RX_FRAME_BUFFER.append(burst_total_payload) # IF CRC TRUE APPEND burst_total_payload TO ARQ_RX_FRAME_BUFFER #print(data_in[7:9]) #BUILDING ACK FRAME ----------------------------------------------- ack_frame = b'\7' + bytes(burst_payload_crc) ack_buffer = bytearray(static.ARQ_PAYLOAD_PER_FRAME) ack_buffer[:len(ack_frame)] = ack_frame # set buffersize to length of data which will be send #TRANSMIT ACK FRAME ----------------------------------------------- time.sleep(2) modem.Transmit(ack_buffer) static.ARQ_RX_BURST_BUFFER = [] else: #IF burst payload crc and input crc are NOT equal print("CRC NOT EQUAL!!!!!") print(data_in[1:3]) static.ARQ_RX_BURST_BUFFER = [] # LOOP THOUGH FRAME BUFFER AND STICK EVERYTHING TOGETHER # WE ALSO CHECK FOR FRAME HEADER AND LAST FRAME complete_frame = bytearray() for frame in range(len(static.ARQ_RX_FRAME_BUFFER)): complete_frame = complete_frame + static.ARQ_RX_FRAME_BUFFER[frame] # -------- DETECT IF WE ALREADY RECEIVED A FRAME HEADER THEN SAVE DATA TO GLOBALS #if burst_total_payload[4:6].startswith(b'\xAA\xAA'): if complete_frame[4:6].startswith(b'\xAA\xAA') or burst_total_payload[4:6].startswith(b'\xAA\xAA'): #print("DAS IST DER ERSTE BURST MIT BOF!!!") #print("FRAME BURSTS = " + str(complete_frame[:2])) #print("FRAME CRC = " + str(complete_frame[2:4])) static.FRAME_CRC = complete_frame[2:4] static.ARQ_RX_FRAME_N_BURSTS = int.from_bytes(bytes(complete_frame[:2]), "big") # -------- DETECT IF WE HAVE ALREADY RECEIVED THE LAST FRAME #if burst_total_payload.rstrip(b'\x00').endswith(b'\xFF\xFF'): #print("DAS IST DER LETZTE BURST MIT EOF!!!") # NOW WE TRY TO SEPARATE THE CRC FOR A CRC CALCULATION frame_payload = complete_frame.rstrip(b'\x00') #REMOVE x00 #print(frame_payload) frame_payload = frame_payload[6:-2] #print(frame_payload) frame_payload_crc = crc_algorithm(frame_payload) frame_payload_crc = frame_payload_crc.to_bytes(2, byteorder='big') if frame_payload_crc == static.FRAME_CRC: print("WHOOOOOOOHOOOOOOOOOOOOOO") static.RX_BUFFER.append(frame_payload) static.ARQ_RX_FRAME_BUFFER = [] print(static.RX_BUFFER[-1]) # HERE: SEND ACK FOR TOTAL FRAME!!! else: print("CRC FOR FRAME NOT EQUAL!") print("FRAME PAYLOAD CRC: " + str(frame_payload_crc)) print("FRAME PAYLOAD: " + str(frame_payload)) print("COMPLETE FRAME: " + str(complete_frame)) #static.ARQ_RX_FRAME_BUFFER = [] # ---> BUFFER ERST LÖSCHEN WENN MINDESTANZAHL AN BURSTS ERHALTEN WORDEN SIND def ack_received(): logging.info("RX | ACK RCVD!") static.ACK_TIMEOUT = 1 #Force timer to stop waiting static.ACK_RECEIVED = 1 #Force data loops of TNC to stop and continue with next frame # static.ARQ_ACK_WAITING_FOR_ID def transmit(data_out): static.ARQ_PAYLOAD_PER_FRAME = static.FREEDV_PAYLOAD_PER_FRAME - 3 #----------------------- BUILD A FRAME WITH CRC AND N BURSTS frame_BOF = b'\xAA\xAA' frame_EOF = b'\xFF\xFF' frame_header_length = 8 n_bursts_prediction = (len(data_out)+frame_header_length) // static.ARQ_PAYLOAD_PER_FRAME + ((len(data_out)+frame_header_length) % static.ARQ_PAYLOAD_PER_FRAME > 0) # aufrunden 3.2 = 4 n_bursts_prediction = n_bursts_prediction.to_bytes(2, byteorder='big') #65535 frame_payload_crc = crc_algorithm(data_out) frame_payload_crc = frame_payload_crc.to_bytes(2, byteorder='big') data_out = n_bursts_prediction + frame_payload_crc + frame_BOF + data_out + frame_EOF # 2 2 2 N 2 print(data_out) # --------------------------------------------- START OF MAIN DATA LOOP static.TX_BUFFER = [data_out[i:i+static.ARQ_PAYLOAD_PER_FRAME] for i in range(0, len(data_out), static.ARQ_PAYLOAD_PER_FRAME)] # split incomming bytes to size of 30bytes - arq payload static.TX_BUFFER_SIZE = len(static.TX_BUFFER) static.ARQ_TX_N_FRAMES = n_frames_per_burst(len(data_out)) # DEFINE NUMBER OF FRAMES PER BURSTS logging.info("TX | TOTAL PAYLOAD BYTES/FRAMES TO SEND: " + str(len(data_out)) + " / " + str(static.TX_BUFFER_SIZE)) #print(static.TX_BUFFER[2]) for n_raw_frame in range(0, static.TX_BUFFER_SIZE, static.ARQ_TX_N_FRAMES): # LOOP THROUGH DATA LIST with steps = ARQ_TX_N_FRAMES # ----------- GENERATE PAYLOAD CRC FOR ARQ_TX_N_FRAMES burst_total_payload = bytearray() #---------------------------------------------------------------------------------------------------------- try: # DETECT IF LAST BURST for i in range(static.ARQ_TX_N_FRAMES): #bytearray(b'111111111111111111111111222222222222222222222222') # we need to make sure, payload data is always as long as static.ARQ_PAYLOAD_PER_FRAME beacuse of CRC! burst_raw_payload = static.TX_BUFFER[n_raw_frame + i] burst_payload = bytearray(static.ARQ_PAYLOAD_PER_FRAME) burst_payload[:len(burst_raw_payload)] = burst_raw_payload # set buffersize to length of data which will be send burst_total_payload = burst_total_payload + burst_payload except IndexError: # IF LAST BURST DETECTED BUILD CRC WITH LESS FRAMES AND SET static.ARQ_TX_N_FRAMES TO VALUE OF REST! print("LAST BURST!!!") burst_total_payload = bytearray() # reset burst_total_payload because of possible input remaining of detecting loop one step above n_last_burst = (static.TX_BUFFER_SIZE % n_raw_frame) print(n_last_burst) static.ARQ_TX_N_FRAMES = n_last_burst for i in range(n_last_burst): #bytearray(b'111111111111111111111111222222222222222222222222') burst_raw_payload = static.TX_BUFFER[n_raw_frame + i] burst_payload = bytearray(static.ARQ_PAYLOAD_PER_FRAME) burst_payload[:len(burst_raw_payload)] = burst_raw_payload # set buffersize to length of data which will be send burst_total_payload = burst_total_payload + burst_payload #---------------------------------------------------------------------------------------------------------- print(burst_total_payload) burst_payload_crc = crc_algorithm(burst_total_payload) burst_payload_crc = burst_payload_crc.to_bytes(2, byteorder='big') print(burst_payload_crc) static.ARQ_ACK_WAITING_FOR_ID = burst_payload_crc #set the global variable so we know for which ACK we are waiting for #---------------------------------------------------------------------------------------------------------- #-------------------- BUILD ARQBURSTS arqburst = [] for i in range(static.ARQ_TX_N_FRAMES): frame_type = 10 + static.ARQ_TX_N_FRAMES frame_type = bytes([frame_type]) payload_data = bytes(static.TX_BUFFER[n_raw_frame + i]) arqframe = frame_type + burst_payload_crc + payload_data buffer = bytearray(static.FREEDV_PAYLOAD_PER_FRAME) # create TX buffer buffer[:len(arqframe)] = arqframe # set buffersize to length of data which will be send arqburst.append(buffer) #---------------------------------------------------------------------------------------------------------- #--------------------------------------------- N ATTEMPTS TO SEND BURSTS IF ACK FAILS for static.TX_N_RETRIES in range(static.TX_N_MAX_RETRIES): static.ACK_RECEIVED = 0 # ----------------------- Loop through ARQ FRAMES BUFFER with N = Numbers of frames which will be send at once for n in range(static.ARQ_TX_N_FRAMES): logging.info("TX | SENDING BURST " + str(n+1) + " / " + str(static.ARQ_TX_N_FRAMES)) modem.Transmit(arqburst[n]) time.sleep(2) #modem.RF.Transmit(arqburst[n]) print(arqburst[n]) # --------------------------- START TIMER ---> IF TIMEOUT REACHED, ACK_TIMEOUT = 1 static.ACK_TIMEOUT = 0 timer = threading.Timer(static.ACK_TIMEOUT_SECONDS * static.ARQ_TX_N_FRAMES, other.timeout) timer.start() # --------------------------- WHILE TIMEOUT NOT REACHED AND NO ACK RECEIVED --> LISTEN logging.info("TX | WAITING FOR ACK") while static.ACK_TIMEOUT == 0 and static.ACK_RECEIVED == 0: static.MODEM_RECEIVE = True else: logging.info("TX | ACK TIMEOUT - SENDING AGAIN") #--------------- BREAK LOOP IF ACK HAS BEEN RECEIVED if static.ACK_RECEIVED == 1: #static.TX_N_RETRIES = 3 break # ----------- if no ACK received and out of retries.....stop frame sending if static.ACK_RECEIVED == 0: logging.info("TX | NO ACK RECEIVED | FRAME NEEDS TO BE RESEND!") break #-------------------------BREAK TX BUFFER LOOP IF ALL PACKETS HAVE BEEN SENT if n_raw_frame == static.TX_BUFFER_SIZE: break # ------------ TIMER TO WAIT UNTIL NEXT PACKAGE WILL BE SEND TO PREVENT TIME ISSEUS time.sleep(5) logging.info("TX | BUFFER EMPTY") # BURST MACHINE TO DEFINE N BURSTS PER FRAME def n_frames_per_burst(len_data): if len_data <= static.ARQ_PAYLOAD_PER_FRAME: n_frames_per_burst = 1 else: n_frames_per_burst = 2 return n_frames_per_burst