FreeDATA/data_handler.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Sun Dec 27 20:43:40 2020

@author: DJ2LS
"""

import logging
import threading
import time
from random import randrange
import asyncio
import sys

import static
import modem
modem = modem.RF()
import helpers




#############################################################################################################    
# ARQ DATA HANDLER
#############################################################################################################

    
def arq_data_received(data_in):

        static.TNC_STATE = 'BUSY'

        static.ARQ_N_FRAME = int.from_bytes(bytes(data_in[:1]), "big")  - 10 #get number of burst frame 
        static.ARQ_N_RX_FRAMES_PER_BURSTS = int.from_bytes(bytes(data_in[1:2]), "big") #get number of bursts from received frame
        static.ARQ_RX_N_CURRENT_ARQ_FRAME = int.from_bytes(bytes(data_in[2:4]), "big") #get current number of total frames
        static.ARQ_N_ARQ_FRAMES_PER_DATA_FRAME = int.from_bytes(bytes(data_in[4:6]), "big") # get get total number of frames      
        
        logging.debug("----------------------------------------------------------------")
        logging.debug("ARQ_N_FRAME: " + str(static.ARQ_N_FRAME))
        logging.debug("ARQ_N_RX_FRAMES_PER_BURSTS: " + str(static.ARQ_N_RX_FRAMES_PER_BURSTS))
        logging.debug("ARQ_RX_N_CURRENT_ARQ_FRAME: " + str(static.ARQ_RX_N_CURRENT_ARQ_FRAME))
        logging.debug("ARQ_N_ARQ_FRAMES_PER_DATA_FRAME: " + str(static.ARQ_N_ARQ_FRAMES_PER_DATA_FRAME))
        logging.debug("----------------------------------------------------------------")

        arq_percent_burst = int((static.ARQ_N_FRAME / static.ARQ_N_RX_FRAMES_PER_BURSTS)*100)
        arq_percent_frame = int(((static.ARQ_RX_N_CURRENT_ARQ_FRAME)/static.ARQ_N_ARQ_FRAMES_PER_DATA_FRAME)*100)      
        
        logging.log(24, "ARQ | RX | " + str(static.ARQ_DATA_CHANNEL_MODE) + " | F:[" + str(static.ARQ_N_FRAME) + "/" + str(static.ARQ_N_RX_FRAMES_PER_BURSTS) + "] [" + str(arq_percent_burst).zfill(3) + "%] T:[" + str(static.ARQ_RX_N_CURRENT_ARQ_FRAME) + "/" + str(static.ARQ_N_ARQ_FRAMES_PER_DATA_FRAME) + "] [" + str(arq_percent_frame).zfill(3) + "%] [BER."+str(static.BER)+"]" )
        
        #allocate ARQ_RX_FRAME_BUFFER as a list with "None" if not already done. This should be done only once per burst!
        # here we will save the N frame of a data frame to N list position so we can explicit search for it
        # delete frame buffer if first frame to make sure the buffer is cleared and no junks of a old frame is remaining
        if static.ARQ_RX_N_CURRENT_ARQ_FRAME == 1:
            static.ARQ_RX_FRAME_BUFFER = []

        try:       
            static.ARQ_RX_FRAME_BUFFER[static.ARQ_RX_N_CURRENT_ARQ_FRAME] = bytes(data_in)                                       

        except IndexError:

            static.ARQ_RX_FRAME_BUFFER = []
            for i in range(0,static.ARQ_N_ARQ_FRAMES_PER_DATA_FRAME+1):
                static.ARQ_RX_FRAME_BUFFER.insert(i,None)
        
            static.ARQ_RX_FRAME_BUFFER[static.ARQ_RX_N_CURRENT_ARQ_FRAME] = bytes(data_in) 
            static.ARQ_FRAME_BOF_RECEIVED = False
            static.ARQ_FRAME_EOF_RECEIVED = False       

                        
        try:       
            static.ARQ_RX_BURST_BUFFER[static.ARQ_N_FRAME] = bytes(data_in)                              
                
        except IndexError:
            
            static.ARQ_RX_BURST_BUFFER = []
            for i in range(0,static.ARQ_N_RX_FRAMES_PER_BURSTS+1):
                static.ARQ_RX_BURST_BUFFER.insert(i,None)
                
            static.ARQ_RX_BURST_BUFFER[static.ARQ_N_FRAME] = bytes(data_in) 
                       
# - ------------------------- ARQ BURST CHECKER             
        # run only if we recieved all ARQ FRAMES per ARQ BURST
        if static.ARQ_RX_BURST_BUFFER.count(None) == 1: #count nones
            logging.info("ARQ | TX | BURST ACK")
            
            #BUILDING ACK FRAME FOR BURST ----------------------------------------------- 
            #ack_payload = b'ACK'
            #ack_frame = b'<' + ack_payload # < = 60   
            
            ack_frame = bytearray(14)
            ack_frame[:1] = bytes([60])
            ack_frame[1:2] = static.DXCALLSIGN_CRC8
            ack_frame[2:3] = static.MYCALLSIGN_CRC8
            #print(ack_frame)
            #TRANSMIT ACK FRAME FOR BURST-----------------------------------------------
            modem.transmit_signalling(ack_frame)
            while static.CHANNEL_STATE == 'SENDING_SIGNALLING':
                time.sleep(0.01)
            static.CHANNEL_STATE = 'RECEIVING_DATA'
            #TRANSMIT_ARQ_ACK_THREAD = threading.Thread(target=modem.transmit_arq_ack, args=[ack_frame], name="TRANSMIT_ARQ_BURST")
            #TRANSMIT_ARQ_ACK_THREAD.start()
            #while static.ARQ_STATE == 'SENDING_ACK':
            #    pass
            
            #clear burst buffer
            static.ARQ_RX_BURST_BUFFER = []
        
        #if decoded N frames are unequal to expected frames per burst
        elif static.ARQ_N_FRAME == static.ARQ_N_RX_FRAMES_PER_BURSTS and static.ARQ_RX_BURST_BUFFER.count(None) != 1:
            
            # --------------- CHECK WHICH BURST FRAMES WE ARE MISSING -------------------------------------------
            missing_frames = b''
            for burstnumber in range(1,len(static.ARQ_RX_BURST_BUFFER)):
                
                if static.ARQ_RX_BURST_BUFFER[burstnumber] == None:
                    #frame_number = static.ARQ_RX_N_CURRENT_ARQ_FRAME - static.ARQ_N_RX_FRAMES_PER_BURSTS + burstnumber
                    #logging.debug("frame_number" + str(frame_number))
                    logging.debug("static.ARQ_RX_N_CURRENT_ARQ_FRAME" + str(static.ARQ_RX_N_CURRENT_ARQ_FRAME))
                    logging.debug("ARQ_N_RX_FRAMES_PER_BURSTS" + str(static.ARQ_N_RX_FRAMES_PER_BURSTS))
                    
                    frame_number = burstnumber
                    frame_number = frame_number.to_bytes(2, byteorder='big')  
                    missing_frames += frame_number
                                
            logging.warning("ARQ | TX | RPT ARQ FRAMES [" + str(missing_frames) + "] [BER."+str(static.BER)+"]") 
            
            #BUILDING RPT FRAME FOR BURST -----------------------------------------------
            #rpt_payload = missing_frames       
            #rpt_frame = b'>' + rpt_payload #> = 63 --> 62?!?!?!?!
            rpt_frame = bytearray(14)
            rpt_frame[:1] = bytes([63])
            rpt_frame[1:2] = static.DXCALLSIGN_CRC8
            rpt_frame[2:3] = static.MYCALLSIGN_CRC8
            rpt_frame[3:9] = missing_frames 
                         
            #TRANSMIT RPT FRAME FOR BURST-----------------------------------------------
            modem.transmit_signalling(rpt_frame)
            while static.CHANNEL_STATE == 'SENDING_SIGNALLING':
                time.sleep(0.01)
            static.CHANNEL_STATE = 'RECEIVING_DATA'      
        
# ---------------------------- FRAME MACHINE
        # ---------------  IF LIST NOT CONTAINS "None" stick everything together 
        complete_data_frame = bytearray()   
        #print("static.ARQ_RX_FRAME_BUFFER.count(None)" + str(static.ARQ_RX_FRAME_BUFFER.count(None)))
        if static.ARQ_RX_FRAME_BUFFER.count(None) == 1: ## 1 because position 0 of list will alaways be None in our case
            logging.debug("DECODING FRAME!")
            for frame in range(1,len(static.ARQ_RX_FRAME_BUFFER)):
                raw_arq_frame = static.ARQ_RX_FRAME_BUFFER[frame]
                arq_frame_payload = raw_arq_frame[8:]
                
                # -------- DETECT IF WE RECEIVED A FRAME HEADER THEN SAVE DATA TO GLOBALS
                if arq_frame_payload[2:4].startswith(static.FRAME_BOF):
                    static.FRAME_CRC = arq_frame_payload[:2]
                    static.ARQ_FRAME_BOF_RECEIVED = True
                    
                    arq_frame_payload = arq_frame_payload.split(static.FRAME_BOF)
                    arq_frame_payload = arq_frame_payload[1]
                    logging.debug("BOF")
                
                # -------- DETECT IF WE RECEIVED A FRAME FOOTER THEN SAVE DATA TO GLOBALS    
                # we need to check for at least one xFF. Sometimes we have only one xFF, because the second one is in the next frame
                if arq_frame_payload.rstrip(b'\x00').endswith(static.FRAME_EOF) or arq_frame_payload.rstrip(b'\x00').endswith(static.FRAME_EOF[:-1]):
                    static.ARQ_FRAME_EOF_RECEIVED = True
                    if arq_frame_payload.rstrip(b'\x00').endswith(static.FRAME_EOF[:-1]):
                        arq_frame_payload = arq_frame_payload.split(static.FRAME_EOF[:-1])
                        arq_frame_payload = arq_frame_payload[0]
                    else:
                        arq_frame_payload = arq_frame_payload.split(static.FRAME_EOF)
                        arq_frame_payload = arq_frame_payload[0]
                    logging.debug("EOF")
                
                # --------- AFTER WE SEPARATED BOF AND EOF, STICK EVERYTHING TOGETHER  
                complete_data_frame = complete_data_frame + arq_frame_payload
                logging.debug(complete_data_frame)           
            
        #check if Begin of Frame BOF and End of Frame EOF are received, then start calculating CRC and sticking everything together
        if static.ARQ_FRAME_BOF_RECEIVED == True and static.ARQ_FRAME_EOF_RECEIVED == True:
        
            frame_payload_crc = helpers.get_crc_16(complete_data_frame)
          
            #IF THE FRAME PAYLOAD CRC IS EQUAL TO THE FRAME CRC WHICH IS KNOWN FROM THE HEADER --> SUCCESS      
            if frame_payload_crc == static.FRAME_CRC:
                 logging.log(25,"ARQ | RX | DATA FRAME SUCESSFULLY RECEIVED! :-) ")
                 
                 #append received frame to RX_BUFFER
                 static.RX_BUFFER.append(complete_data_frame)
          
                #BUILDING ACK FRAME FOR DATA FRAME -----------------------------------------------              
                 #ack_payload = b'FRAME_ACK'
                 #ack_frame = b'='+ ack_payload + bytes(static.FRAME_CRC) # < = 61 
                 
                 ack_frame = bytearray(14)
                 ack_frame[:1] = bytes([61])
                 ack_frame[1:2] = static.DXCALLSIGN_CRC8
                 ack_frame[2:3] = static.MYCALLSIGN_CRC8                  
            
                #TRANSMIT ACK FRAME FOR BURST-----------------------------------------------
                 time.sleep(1) #0.5
                 logging.info("ARQ | TX | ARQ DATA FRAME ACK [" + str(static.FRAME_CRC.hex()) +"] [BER."+str(static.BER)+"]")
                 
                 modem.transmit_signalling(ack_frame)
                 while static.CHANNEL_STATE == 'SENDING_SIGNALLING':
                     time.sleep(0.01)  
                                    
                 static.CHANNEL_STATE = 'RECEIVING_SIGNALLING'
                 # clearing buffers and resetting counters
                 static.ARQ_RX_BURST_BUFFER = []
                 static.ARQ_RX_FRAME_BUFFER = []
                 static.ARQ_FRAME_BOF_RECEIVED = False
                 static.ARQ_FRAME_EOF_RECEIVED = False
                 static.ARQ_N_ARQ_FRAMES_PER_DATA_FRAME = 0
                 static.ARQ_RX_N_CURRENT_ARQ_FRAME = 0
                 static.TNC_STATE = 'IDLE'
                 static.ARQ_SEND_KEEP_ALIVE = True
                 static.ARQ_READY_FOR_DATA = False
                 
                 logging.info("DATA ["+ str(static.MYCALLSIGN, 'utf-8') + "]<< >>["+ str(static.DXCALLSIGN, 'utf-8') + "] [BER."+str(static.BER)+"]")
                 
            else:
                print("ARQ_FRAME_BOF_RECEIVED " + str(static.ARQ_FRAME_BOF_RECEIVED))
                print("ARQ_FRAME_EOF_RECEIVED " + str(static.ARQ_FRAME_EOF_RECEIVED))
                logging.error("ARQ | RX | DATA FRAME NOT SUCESSFULLY RECEIVED!")
                static.ARQ_STATE = 'IDLE'
                static.ARQ_SEND_KEEP_ALIVE = True
                static.ARQ_READY_FOR_DATA = False
                logging.info("DATA ["+ str(static.MYCALLSIGN, 'utf-8') + "]<< >>["+ str(static.DXCALLSIGN, 'utf-8') + "] [BER."+str(static.BER)+"]")
        

def arq_transmit(data_out):
            # we need to set payload per frame manually at this point. maybe we can do this more dynmic.
            if static.ARQ_DATA_CHANNEL_MODE == 10:
                payload_per_frame = 512-2
            elif static.ARQ_DATA_CHANNEL_MODE == 11:
                payload_per_frame = 256-2
            elif static.ARQ_DATA_CHANNEL_MODE == 12:
                payload_per_frame = 128-2
            elif static.ARQ_DATA_CHANNEL_MODE == 14:
                payload_per_frame = 16-2
            else:
                payload_per_frame = 16-2
            
            static.ARQ_PAYLOAD_PER_FRAME = payload_per_frame - 8 

            #print("static.ARQ_DATA_PAYLOAD_PER_FRAME " + str(static.FREEDV_DATA_PAYLOAD_PER_FRAME))
            #print("static.ARQ_PAYLOAD_PER_FRAME " + str(static.ARQ_PAYLOAD_PER_FRAME))

            frame_header_length = 6 #4
                        
            n_arq_frames_per_data_frame = (len(data_out)+frame_header_length) // static.ARQ_PAYLOAD_PER_FRAME + ((len(data_out)+frame_header_length) % static.ARQ_PAYLOAD_PER_FRAME > 0) 
            
            frame_payload_crc = helpers.get_crc_16(data_out)

            # This is the total frame with frame header, which will be send
            data_out =  frame_payload_crc + static.FRAME_BOF + data_out + static.FRAME_EOF
            #                     2                 2              N           2
            
            # --------------------------------------------- LETS CREATE A BUFFER BY SPLITTING THE FILES INTO PEACES
            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)]
            static.TX_BUFFER_SIZE = len(static.TX_BUFFER)
            
            logging.info("ARQ | TX | M:" + str(static.ARQ_DATA_CHANNEL_MODE) + " | DATA FRAME --- BYTES: " + str(len(data_out)) + " ARQ FRAMES: " + str(static.TX_BUFFER_SIZE))
      
            # --------------------------------------------- THIS IS THE MAIN LOOP-----------------------------------------------------------------
            static.ARQ_N_SENT_FRAMES = 0 # SET N SENT FRAMES TO 0 FOR A NEW SENDING CYCLE
            while static.ARQ_N_SENT_FRAMES <= static.TX_BUFFER_SIZE:

                static.ARQ_TX_N_FRAMES_PER_BURST = get_n_frames_per_burst()
                           
                # ----------- CREATE FRAME TOTAL PAYLOAD TO BE ABLE TO CREATE CRC FOR IT
                try: # DETECT IF LAST BURST TO PREVENT INDEX ERROR OF BUFFER
                    
                    for i in range(static.ARQ_TX_N_FRAMES_PER_BURST): # Loop through TX_BUFFER LIST
                        len(static.TX_BUFFER[static.ARQ_N_SENT_FRAMES + i]) #we calculate the length to trigger a list index error                                    
                
                except IndexError: # IF LAST BURST DETECTED BUILD CRC WITH LESS FRAMES AND SET static.ARQ_TX_N_FRAMES_PER_BURST TO VALUE OF REST!
                     
                     if static.ARQ_N_SENT_FRAMES == 0  and (static.ARQ_TX_N_FRAMES_PER_BURST > static.TX_BUFFER_SIZE): #WE CANT DO MODULO 0 --> CHECK IF FIRST FRAME == LAST FRAME
                          static.ARQ_TX_N_FRAMES_PER_BURST = static.TX_BUFFER_SIZE
                     
                     elif static.ARQ_N_SENT_FRAMES == 1 and (static.ARQ_TX_N_FRAMES_PER_BURST > static.TX_BUFFER_SIZE): # MODULO 1 WILL ALWAYS BE 0 --> THIS FIXES IT
                            static.ARQ_TX_N_FRAMES_PER_BURST = static.TX_BUFFER_SIZE - static.ARQ_N_SENT_FRAMES  
                     
                     else:
                         static.ARQ_TX_N_FRAMES_PER_BURST = (static.TX_BUFFER_SIZE % static.ARQ_N_SENT_FRAMES)
                
                #--------------------------------------------- N ATTEMPTS TO SEND BURSTS IF ACK RECEPTION FAILS
                for static.TX_N_RETRIES in range(static.TX_N_MAX_RETRIES):
                 
                    if static.ARQ_N_SENT_FRAMES + 1 <= static.TX_BUFFER_SIZE:
                        logging.log(24, "ARQ | TX | M:" + str(static.ARQ_DATA_CHANNEL_MODE) + " | F:[" + str(static.ARQ_N_SENT_FRAMES+1) + "-" + str(static.ARQ_N_SENT_FRAMES + static.ARQ_TX_N_FRAMES_PER_BURST) + "] | T:[" + str(static.ARQ_N_SENT_FRAMES) + "/" + str(static.TX_BUFFER_SIZE) + "] [" + str(int(static.ARQ_N_SENT_FRAMES/(static.TX_BUFFER_SIZE)*100)).zfill(3) + "%] | A:[" + str(static.TX_N_RETRIES+1) + "/" + str(static.TX_N_MAX_RETRIES) + "] [BER."+str(static.BER)+"]")
                    
                                        
                    # lets start a thread to transmit nonblocking
                    #TRANSMIT_ARQ_BURST_THREAD = threading.Thread(target=modem.transmit_arq_burst, name="TRANSMIT_ARQ_BURST")
                    #TRANSMIT_ARQ_BURST_THREAD.start()
                    #asyncio.run(modem.transmit_arq_burst())
                    #await modem.transmit_arq_burst()
                    modem.transmit_arq_burst()
                    # lets wait during sending. After sending is finished we will continue
                    while static.CHANNEL_STATE == 'SENDING_DATA':    
                        time.sleep(0.01)
                       
                    # --------------------------- START TIMER FOR WAITING FOR ACK ---> IF TIMEOUT REACHED, ACK_TIMEOUT = 1
                    
                    logging.info("ARQ | RX | WAITING FOR BURST ACK")
                    static.CHANNEL_STATE = 'RECEIVING_SIGNALLING'
                    #print(static.CHANNEL_STATE)
                       
                    helpers.arq_reset_timeout(False)
                    helpers.arq_reset_ack(False)
                    #print(static.ARQ_RX_ACK_TIMEOUT)
                    #print("timeout......?!?")
                    #asyncio.ensure_future(helpers.set_variable_after_timeout())
                    ##################task = asyncio.create_task(helpers.set_after_timeout())
                    #async with trio.open_nursery() as nursery:
                    #   nursery.start_soon(helpers.set_after_timeout()) 
                    
                    
                    #print("TIMEOUT glaube gestartet...")
                    #print(task)
                    #print(static.ARQ_RX_ACK_TIMEOUT)
                    
                    acktimer = threading.Timer(static.ARQ_RX_ACK_TIMEOUT_SECONDS, helpers.arq_ack_timeout)
                    acktimer.start() 
                    
                    logging.debug(".............................")
                    logging.debug("static.ARQ_STATE " + str(static.ARQ_STATE))
                    logging.debug("static.ARQ_FRAME_ACK_RECEIVED " + str(static.ARQ_FRAME_ACK_RECEIVED))
                    logging.debug("static.ARQ_ACK_RECEIVED " + str(static.ARQ_ACK_RECEIVED))
                    logging.debug("static.ARQ_RX_ACK_TIMEOUT " + str(static.ARQ_RX_ACK_TIMEOUT))
                    logging.debug("static.ARQ_RPT_RECEIVED " + str(static.ARQ_RPT_RECEIVED))
                    logging.debug(".............................")

                    # --------------------------- WHILE TIMEOUT NOT REACHED AND NO ACK RECEIVED --> LISTEN
                    while static.ARQ_ACK_RECEIVED != True and static.ARQ_RPT_RECEIVED != True and static.ARQ_FRAME_ACK_RECEIVED != True and static.ARQ_RX_FRAME_TIMEOUT != True and static.ARQ_RX_ACK_TIMEOUT != True:
                        time.sleep(0.01) # lets reduce CPU load a little bit
                        logging.debug(static.CHANNEL_STATE)
                                            
                    if static.ARQ_RPT_RECEIVED == True:
                    
                        logging.warning("ARQ | RX | REQUEST FOR REPEATING FRAMES: " + str(static.ARQ_RPT_FRAMES))
                        logging.warning("ARQ | TX | SENDING REQUESTED FRAMES: " + str(static.ARQ_RPT_FRAMES))                  
                        
                        #TRANSMIT_ARQ_BURST_THREAD = threading.Thread(target=modem.transmit_arq_burst, name="TRANSMIT_ARQ_BURST")
                        #TRANSMIT_ARQ_BURST_THREAD.start()
                        #asyncio.run(modem.transmit_arq_burst())
                        #await modem.transmit_arq_burst()
                        modem.transmit_arq_burst()
                        # lets wait during sending. After sending is finished we will continue
                        while static.ARQ_STATE == 'SENDING_DATA':
                            time.sleep(0.01)
                        static.CHANNEL_STATE = 'RECEIVING_SIGNALLING'
             
                        helpers.arq_reset_timeout(False)
                        helpers.arq_reset_ack(False)
                    
                        rpttimer = threading.Timer(static.ARQ_RX_RPT_TIMEOUT_SECONDS, helpers.arq_rpt_timeout)
                        rpttimer.start() 
                    
                        while static.ARQ_ACK_RECEIVED == False and static.ARQ_FRAME_ACK_RECEIVED == False and static.ARQ_RX_RPT_TIMEOUT == False:                 
                            time.sleep(0.01) # lets reduce CPU load a little bit
                            logging.debug(static.ARQ_STATE)
                            
                            if static.ARQ_ACK_RECEIVED == True:
                            
                                logging.info("ARQ | RX | ACK AFTER RPT")
                                rpttimer.cancel()
                                helpers.arq_reset_ack(True)
                                static.ARQ_RPT_FRAMES = []

                        if static.ARQ_RX_RPT_TIMEOUT == True and static.ARQ_ACK_RECEIVED == False:
                            
                            logging.error("ARQ | Burst lost....")
                            
                            helpers.arq_reset_ack(False)
                            static.ARQ_RPT_FRAMES = []
                   
                   #--------------------------------------------------------------------------------------------------------------
                   
                    elif static.ARQ_ACK_RECEIVED == 0 and static.ARQ_RX_ACK_TIMEOUT == 1:
                        logging.warning("ARQ | RX | ACK TIMEOUT!")
                        pass #no break here so we can continue with the next try of repeating the burst
                 
                    #--------------- BREAK LOOP IF ACK HAS BEEN RECEIVED
                    elif static.ARQ_ACK_RECEIVED == True:
                        logging.info("ARQ | RX | ACK")
                        acktimer.cancel()       
                        #-----------IF ACK RECEIVED, INCREMENT ITERATOR FOR MAIN LOOP TO PROCEED WITH NEXT FRAMES/BURST
                        static.ARQ_N_SENT_FRAMES = static.ARQ_N_SENT_FRAMES + static.ARQ_TX_N_FRAMES_PER_BURST
                        break
                        
                    #--------------- BREAK LOOP IF FRAME ACK HAS BEEN RECEIVED EARLIER AS EXPECTED
                    elif static.ARQ_FRAME_ACK_RECEIVED == True:
                        
                        logging.info("ARQ | RX | EARLY FRAME ACK RECEIVED")
                        
                        #static.ARQ_N_SENT_FRAMES = #static.TX_BUFFER_SIZE
                        static.ARQ_N_SENT_FRAMES = static.ARQ_N_SENT_FRAMES + static.ARQ_TX_N_FRAMES_PER_BURST
                        break
                        
                    else:
                        logging.debug("------------------------------->NO RULE MATCHED!")
                        break            
                        
                        
                #--------------------------------WAITING AREA FOR FRAME ACKs        
                
                logging.debug("static.ARQ_N_SENT_FRAMES         " + str(static.ARQ_N_SENT_FRAMES))
                logging.debug("static.TX_BUFFER_SIZE            " + str(static.TX_BUFFER_SIZE))
                logging.debug("static.TX_N_RETRIES              " + str(static.TX_N_RETRIES))
                logging.debug("static.TX_N_MAX_RETRIES          " + str(static.TX_N_MAX_RETRIES))  
                logging.debug("static.ARQ_STATE                 " + str(static.ARQ_STATE))
                logging.debug("static.ARQ_FRAME_ACK_RECEIVED    " + str(static.ARQ_FRAME_ACK_RECEIVED))
                logging.debug("static.ARQ_RX_FRAME_TIMEOUT      " + str(static.ARQ_RX_FRAME_TIMEOUT))
                logging.debug("static.ARQ_ACK_RECEIVED          " + str(static.ARQ_ACK_RECEIVED))
                logging.debug("static.ARQ_RX_ACK_TIMEOUT        " + str(static.ARQ_RX_ACK_TIMEOUT))
                logging.debug("static.ARQ_RPT_RECEIVED          " + str(static.ARQ_RPT_RECEIVED))     
                logging.debug("static.ARQ_TX_N_FRAMES_PER_BURST " + str(static.ARQ_TX_N_FRAMES_PER_BURST)) 
                
                frametimer = threading.Timer(static.ARQ_RX_FRAME_TIMEOUT_SECONDS, helpers.arq_frame_timeout)
                frametimer.start()
                static.CHANNEL_STATE = 'RECEIVING_SIGNALLING'
                
                # wait for frame ACK if we processed the last frame/burst
                while static.ARQ_FRAME_ACK_RECEIVED == False and static.ARQ_RX_FRAME_TIMEOUT == False and static.ARQ_N_SENT_FRAMES == static.TX_BUFFER_SIZE:                 
                        time.sleep(0.01) # lets reduce CPU load a little bit
                        #print(static.ARQ_STATE) 
                        logging.debug("WAITING FOR FRAME ACK")
                       
                             
                # ----------- if no ACK received and out of retries.....stop frame sending
                if static.ARQ_ACK_RECEIVED == False and static.ARQ_FRAME_ACK_RECEIVED == False and static.ARQ_RX_ACK_TIMEOUT == True:
                    logging.error("ARQ | TX | NO ACK RECEIVED | DATA SHOULD BE RESEND!")
                    static.CHANNEL_STATE = 'RECEIVING_SIGNALLING'
                    logging.error("------------------------------------------------------")
                    break

                #-------------------------BREAK TX BUFFER LOOP IF ALL PACKETS HAVE BEEN SENT AND WE GOT A FRAME ACK
                elif static.ARQ_N_SENT_FRAMES == static.TX_BUFFER_SIZE and static.ARQ_FRAME_ACK_RECEIVED == True:
                    logging.log(25,"ARQ | RX | FRAME ACK RECEIVED - DATA TRANSMITTED! :-)")
                    static.CHANNEL_STATE = 'RECEIVING_SIGNALLING'
                    break
                
                elif static.ARQ_FRAME_ACK_RECEIVED == False and static.ARQ_RX_FRAME_TIMEOUT == True:
                    logging.error("ARQ | TX | NO FRAME ACK RECEIVED")
                    static.CHANNEL_STATE = 'RECEIVING_DATA'
                    break  
 
                else:
                    logging.debug("NO MATCHING RULE AT THE END")
                    
                    # stop all timers
                    try:
                        frametimer.cancel()
                    except Exception:
                        pass 
                    
                    try:
                        acktimer.cancel()
                    except Exception:
                        pass 

            # IF TX BUFFER IS EMPTY / ALL FRAMES HAVE BEEN SENT --> HERE WE COULD ADD AN static.VAR for IDLE STATE    
            
            logging.info("ARQ | TX | BUFFER EMPTY")
            helpers.arq_reset_frame_machine()
            #await asyncio.sleep(2)
            time.sleep(2)
            logging.info("DATA ["+ str(static.MYCALLSIGN, 'utf-8') + "]<< >>["+ str(static.DXCALLSIGN, 'utf-8') + "] [BER."+str(static.BER)+"]")
            arq_transmit_keep_alive()
            
            # this should close our thread so we are saving memory...
            #https://stackoverflow.com/questions/905189/why-does-sys-exit-not-exit-when-called-inside-a-thread-in-python
            sys.exit()


# BURST MACHINE TO DEFINE N BURSTS PER FRAME    ---> LATER WE CAN USE CHANNEL MESSUREMENT TO SET FRAMES PER BURST         
def get_n_frames_per_burst():
    #n_frames_per_burst = randrange(1,10)
    n_frames_per_burst = 1   
    return n_frames_per_burst
    
    
    
def burst_ack_received():
    static.ARQ_ACK_RECEIVED = True #Force data loops of TNC to stop and continue with next frame

    

def frame_ack_received():
    static.ARQ_FRAME_ACK_RECEIVED = True #Force data loops of TNC to stop and continue with next frame
  
    

def burst_rpt_received(data_in):
    static.ARQ_RPT_RECEIVED = True
    static.ARQ_RPT_FRAMES = []
    
    missing_area = bytes(data_in[1:9])
    
    for i in range(0,6,2):     
        if not missing_area[i:i+2].endswith(b'\x00\x00'):
            missing = missing_area[i:i+2]
            static.ARQ_RPT_FRAMES.insert(0,missing)
            
#############################################################################################################    
# ARQ CONNECT HANDLER
#############################################################################################################
    
async def arq_connect():
    static.ARQ_STATE = 'CONNECTING' 
    logging.info("CONN ["+ str(static.MYCALLSIGN, 'utf-8') + "]-> <-["+ str(static.DXCALLSIGN, 'utf-8') + "] [BER."+str(static.BER)+"]")
    frame_type = bytes([220])

    connection_frame = bytearray(14)
    connection_frame[:1] = frame_type
    connection_frame[1:2] = static.DXCALLSIGN_CRC8
    connection_frame[2:3] = static.MYCALLSIGN_CRC8
    connection_frame[3:9] = static.MYCALLSIGN           # we need the full CALLSIGN, if we are doing a connect without ping and cq
    #connection_frame[12:13] = bytes([static.ARQ_DATA_CHANNEL_MODE])
    #connection_frame[13:14] = bytes([static.ARQ_READY_FOR_DATA])
    #print(connection_frame)

    modem.transmit_signalling(connection_frame)
    while static.CHANNEL_STATE == 'SENDING_SIGNALLING':
        time.sleep(0.01)    
        
def arq_received_connect(data_in):
    static.ARQ_STATE = 'CONNECTING' 
    
    static.DXCALLSIGN = bytes(data_in[3:9]).rstrip(b'\x00')
    static.DXCALLSIGN_CRC8 = helpers.get_crc_8(static.DXCALLSIGN)    
    #static.FREEDV_DATA_MODE = int.from_bytes(bytes(data_in[12:13]), "big")

    logging.info("CONN ["+ str(static.MYCALLSIGN, 'utf-8') + "]-> <-["+ str(static.DXCALLSIGN, 'utf-8') + "] [BER."+str(static.BER)+"]")

    frame_type = bytes([221])
    connection_frame = bytearray(14)
    connection_frame[:1] = frame_type
    connection_frame[1:2] = static.DXCALLSIGN_CRC8
    connection_frame[2:3] = static.MYCALLSIGN_CRC8
    #connection_frame[12:13] = bytes([static.FREEDV_DATA_MODE])

    #send ACK for connect
    modem.transmit_signalling(connection_frame)
    while static.CHANNEL_STATE == 'SENDING_SIGNALLING':
        time.sleep(0.01)
            
                
def arq_transmit_keep_alive():
    frame_type = bytes([221])
    connection_frame = bytearray(14)
    connection_frame[:1] = frame_type
    connection_frame[1:2] = static.DXCALLSIGN_CRC8
    connection_frame[2:3] = static.MYCALLSIGN_CRC8
    
    modem.transmit_signalling(connection_frame)
    while static.CHANNEL_STATE == 'SENDING_SIGNALLING':
        time.sleep(0.01)   
   
def arq_received_connect_keep_alive(data_in):
    if static.ARQ_SEND_KEEP_ALIVE == True and (static.ARQ_STATE == 'CONNECTING' or static.ARQ_STATE == 'CONNECTED'):
        logging.info("CONN ["+ str(static.MYCALLSIGN, 'utf-8') + "] >|< ["+ str(static.DXCALLSIGN, 'utf-8') + "] [BER."+str(static.BER)+"]")
        static.ARQ_STATE = 'CONNECTED'
        
        frame_type = bytes([221])  
        connection_frame = bytearray(14)
        connection_frame[:1] = frame_type
        connection_frame[1:2] = static.DXCALLSIGN_CRC8
        connection_frame[2:3] = static.MYCALLSIGN_CRC8
        connection_frame[12:13] = bytes([static.ARQ_DATA_CHANNEL_MODE])
        connection_frame[13:14] = bytes([0]) 
        
        #lets wait a second before sending
        acktimer = threading.Timer(1.0, modem.transmit_signalling, args=[connection_frame])
        acktimer.start()
        while static.CHANNEL_STATE == 'SENDING_SIGNALLING':
            time.sleep(0.01) 
    else:
        pass
        #print("keep alive = False")
#############################################################################################################    
# ARQ DATA CHANNEL HANDLER
#############################################################################################################

            
async def arq_open_data_channel():
    # we need to wait until the last keep alive has been sent.

    logging.info("DATA ["+ str(static.MYCALLSIGN, 'utf-8') + "]>> <<["+ str(static.DXCALLSIGN, 'utf-8') + "] [BER."+str(static.BER)+"]")
    static.ARQ_SEND_KEEP_ALIVE = False
    static.ARQ_DATA_CHANNEL_MODE = 12

    while static.CHANNEL_STATE == 'SENDING_SIGNALLING':
        time.sleep(0.01)
    #print("wir warten 2 sekunden...")
    await asyncio.sleep(4)
     
    connection_frame = bytearray(14)
    connection_frame[:1] = bytes([225])
    connection_frame[1:2] = static.DXCALLSIGN_CRC8
    connection_frame[2:3] = static.MYCALLSIGN_CRC8
    connection_frame[12:13] = bytes([static.ARQ_DATA_CHANNEL_MODE])
    #connection_frame[13:14] = bytes([225]) 


    modem.transmit_signalling(connection_frame)
    while static.CHANNEL_STATE == 'SENDING_SIGNALLING':
        time.sleep(0.01)    
    
            
def arq_received_data_channel_opener(data_in):
    logging.info("DATA ["+ str(static.MYCALLSIGN, 'utf-8') + "]>> <<["+ str(static.DXCALLSIGN, 'utf-8') + "] [BER."+str(static.BER)+"]")
    static.ARQ_SEND_KEEP_ALIVE = False
    static.ARQ_DATA_CHANNEL_MODE = int.from_bytes(bytes(data_in[12:13]), "big")
    #static.ARQ_READY_FOR_DATA = int.from_bytes(bytes(data_in[13:14]), "big")
    
    connection_frame = bytearray(14)
    connection_frame[:1] = bytes([226])
    connection_frame[1:2] = static.DXCALLSIGN_CRC8
    connection_frame[2:3] = static.MYCALLSIGN_CRC8
    connection_frame[12:13] = bytes([static.ARQ_DATA_CHANNEL_MODE])
    #connection_frame[13:14] = bytes([226]) 

    modem.transmit_signalling(connection_frame)
    while static.CHANNEL_STATE == 'SENDING_SIGNALLING':
        time.sleep(0.01)
    
    #print("waiting for data....")
    static.CHANNEL_STATE = 'RECEIVING_DATA'
    # einen timeout benötigen wir auch noch....    
    # und ab hier geht es dann in den "RECEIVING_DATA" mode....
            
def arq_received_channel_is_open(data_in):
    static.ARQ_SEND_KEEP_ALIVE == False
    
    if static.ARQ_DATA_CHANNEL_MODE == int.from_bytes(bytes(data_in[12:13]), "big"):
        logging.info("DATA ["+ str(static.MYCALLSIGN, 'utf-8') + "]>>|<<["+ str(static.DXCALLSIGN, 'utf-8') + "] [BER."+str(static.BER)+"]")
        time.sleep(1)
        static.ARQ_READY_FOR_DATA = True


#############################################################################################################
# DISCONNECT HANDLER
#############################################################################################################  

async def arq_disconnect():
 
    # we need to create a "force ignore all" so we don't receive frames any more... Then we don't need a timer
    static.ARQ_SEND_KEEP_ALIVE == False
    static.ARQ_STATE = 'DISCONNECTING' 
    logging.info("DISC ["+ str(static.MYCALLSIGN, 'utf-8') + "] <-> ["+ str(static.DXCALLSIGN, 'utf-8') + "] [BER."+str(static.BER)+"]")   
    #frame_type = bytes([222])
    #disconnection_frame = frame_type + static.MYCALLSIGN
    
    disc_frame = bytearray(14)
    disc_frame[:1] = bytes([222])
    disc_frame[1:2] = static.DXCALLSIGN_CRC8
    disc_frame[2:3] = static.MYCALLSIGN_CRC8
           
    #while static.CHANNEL_STATE == 'SENDING_SIGNALLING':
    #    time.sleep(0.01)
    
    await asyncio.sleep(4)
    modem.transmit_signalling(disc_frame)
    while static.CHANNEL_STATE == 'SENDING_SIGNALLING':
        time.sleep(0.01) 
           
    logging.info("DISC ["+ str(static.MYCALLSIGN, 'utf-8') + "]< X >["+ str(static.DXCALLSIGN, 'utf-8') + "] [BER."+str(static.BER)+"]")   
    static.ARQ_STATE = 'IDLE'
    static.DXCALLSIGN = b''
    static.DXCALLSIGN_CRC8 = b''
     
def arq_disconnect_received(data_in):
    static.ARQ_STATE = 'DISCONNECTED'     
    logging.info("DISC ["+ str(static.MYCALLSIGN, 'utf-8') + "]< X >["+ str(static.DXCALLSIGN, 'utf-8') + "] [BER."+str(static.BER)+"]")   
    static.ARQ_STATE = 'DISCONNECTED'
    static.TNC_STATE = 'IDLE'    
    static.DXCALLSIGN = b''
    static.DXCALLSIGN_CRC8 = b''


    
#############################################################################################################
# PING HANDLER
#############################################################################################################    
    
async def transmit_ping(callsign):
    static.DXCALLSIGN = bytes(callsign, 'utf-8').rstrip(b'\x00')
    static.DXCALLSIGN_CRC8 = helpers.get_crc_8(static.DXCALLSIGN)
    logging.info("PING ["+ str(static.MYCALLSIGN, 'utf-8') + "] >>> [" + str(static.DXCALLSIGN, 'utf-8') + "] [BER."+str(static.BER)+"]")
    
    ping_frame = bytearray(14)
    ping_frame[:1] = bytes([210])
    ping_frame[1:2] = static.DXCALLSIGN_CRC8
    ping_frame[2:3] = static.MYCALLSIGN_CRC8
    ping_frame[3:9] = static.MYCALLSIGN
    

    # wait while sending....
    modem.transmit_signalling(ping_frame)
    while static.CHANNEL_STATE == 'SENDING_SIGNALLING':
        time.sleep(0.01)    
        
def received_ping(data_in):

    static.DXCALLSIGN_CRC8 = bytes(data_in[2:3]).rstrip(b'\x00')
    static.DXCALLSIGN = bytes(data_in[3:9]).rstrip(b'\x00')

    logging.info("PING ["+ str(static.MYCALLSIGN, 'utf-8') + "] <<< ["+ str(static.DXCALLSIGN, 'utf-8') + "] [BER."+str(static.BER)+"]")

    ping_frame = bytearray(14)
    ping_frame[:1] = bytes([211])
    ping_frame[1:2] = static.DXCALLSIGN_CRC8
    ping_frame[2:3] = static.MYCALLSIGN_CRC8
    ping_frame[3:9] = static.MYCALLSIGN
    
    # wait while sending....
    modem.transmit_signalling(ping_frame)
    while static.CHANNEL_STATE == 'SENDING_SIGNALLING':
        time.sleep(0.01)                   
def received_ping_ack(data_in):

    static.DXCALLSIGN_CRC8 = bytes(data_in[2:3]).rstrip(b'\x00')
    static.DXCALLSIGN = bytes(data_in[3:9]).rstrip(b'\x00')

    logging.info("PING [" + str(static.DXCALLSIGN, 'utf-8') + "] >|< [" + str(static.MYCALLSIGN, 'utf-8') + "] [BER."+str(static.BER)+"]")
    static.TNC_STATE = 'IDLE'

#############################################################################################################
# BROADCAST HANDLER
############################################################################################################# 
        
async def transmit_cq():
    logging.info("CQ CQ CQ")
    
    cq_frame = bytearray(14)
    cq_frame[:1] = bytes([200])
    cq_frame[1:2] = b'\x01'
    cq_frame[2:3] = static.MYCALLSIGN_CRC8
    cq_frame[3:9] = static.MYCALLSIGN
    
    for i in range(0,3):
        
        modem.transmit_signalling(cq_frame)
        while static.CHANNEL_STATE == 'SENDING_SIGNALLING':
            time.sleep(0.01)
                         
def received_cq(data_in):
    static.DXCALLSIGN = b''
    static.DXCALLSIGN_CRC8 = b''
    logging.info("CQ [" + str(bytes(data_in[3:9]), 'utf-8') + "] [BER."+str(static.BER)+"]")  
    
    ## here we add the received station to the heard stations buffer
    dxcallsign = bytes(data_in[3:9]).rstrip(b'\x00')
    # check if buffer empty
    if len(static.HEARD_STATIONS) == 0:
        static.HEARD_STATIONS.append([dxcallsign, int(time.time())])
    # if not, we search and update 
    else:
        for i in range(0,len(static.HEARD_STATIONS)):
            # update callsign with new timestamp
            if static.HEARD_STATIONS[i].count(dxcallsign) > 0:
                static.HEARD_STATIONS[i] = [dxcallsign, int(time.time())]
                break
            # insert if nothing found
            if i == len(static.HEARD_STATIONS)-1:
                static.HEARD_STATIONS.append([dxcallsign, int(time.time())])
                break
          

async def transmit_beacon():
    logging.info("BEACON")
    frame_type = bytes([230])
    print(frame_type)
    beacon_frame = frame_type + static.MYCALLSIGN
    while static.TNC_STATE == 'BEACON':
        await asyncio.sleep(60)
        modem.transmit_signalling(beacon_frame)
        while static.CHANNEL_STATE == 'SENDING_SIGNALLING':
            time.sleep(0.01)