FreeDATA/tnc/helpers.py
dj2ls 57e4af83af first test with 24bit crc
moved from 16bit crc to 24bit crc...First test for ping and file transfer seems to be working... This has been too easy... 🤔
2022-04-19 11:09:11 +02:00

393 lines
11 KiB
Python

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Fri Dec 25 21:25:14 2020
@author: DJ2LS
"""
import time
import crcengine
import static
def wait(seconds):
"""
Args:
seconds:
Returns:
"""
timeout = time.time() + seconds
while time.time() < timeout:
time.sleep(0.01)
return True
def get_crc_8(data):
"""Author: DJ2LS
Get the CRC8 of a byte string
param: data = bytes()
Args:
data:
Returns:
"""
crc_algorithm = crcengine.new('crc8-ccitt') # load crc8 library
crc_data = crc_algorithm(data)
crc_data = crc_data.to_bytes(1, byteorder='big')
return crc_data
def get_crc_16(data):
"""Author: DJ2LS
Get the CRC16 of a byte string
param: data = bytes()
Args:
data:
Returns:
"""
crc_algorithm = crcengine.new('crc16-ccitt-false') # load crc16 library
crc_data = crc_algorithm(data)
crc_data = crc_data.to_bytes(2, byteorder='big')
return crc_data
def get_crc_24(data):
"""Author: DJ2LS
Get the CRC24-OPENPGP of a byte string
https://github.com/GardenTools/CrcEngine#examples
param: data = bytes()
Args:
data:
Returns:
"""
crc_algorithm = crcengine.create(0x864cfb, 24, 0xb704ce, ref_in=False,
ref_out=False, xor_out=0,
name='crc-24-openpgp')
crc_data = crc_algorithm(data)
crc_data = crc_data.to_bytes(3, byteorder='big')
return crc_data
def get_crc_32(data):
"""Author: DJ2LS
Get the CRC32 of a byte string
param: data = bytes()
Args:
data:
Returns:
"""
crc_algorithm = crcengine.new('crc32') # load crc16 library
crc_data = crc_algorithm(data)
crc_data = crc_data.to_bytes(4, byteorder='big')
return crc_data
def add_to_heard_stations(dxcallsign, dxgrid, datatype, snr, offset, frequency):
"""
Args:
dxcallsign:
dxgrid:
datatype:
snr:
offset:
frequency:
Returns:
"""
# check if buffer empty
if len(static.HEARD_STATIONS) == 0:
static.HEARD_STATIONS.append([dxcallsign, dxgrid, int(time.time()), datatype, snr, offset, frequency])
# 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, dxgrid, int(time.time()), datatype, snr, offset, frequency]
break
# insert if nothing found
if i == len(static.HEARD_STATIONS) - 1:
static.HEARD_STATIONS.append([dxcallsign, dxgrid, int(time.time()), datatype, snr, offset, frequency])
break
# for idx, item in enumerate(static.HEARD_STATIONS):
# if dxcallsign in item:
# item = [dxcallsign, int(time.time())]
# static.HEARD_STATIONS[idx] = item
def callsign_to_bytes(callsign):
"""
Args:
callsign:
Returns:
"""
# http://www.aprs.org/aprs11/SSIDs.txt
#-0 Your primary station usually fixed and message capable
#-1 generic additional station, digi, mobile, wx, etc
#-2 generic additional station, digi, mobile, wx, etc
#-3 generic additional station, digi, mobile, wx, etc
#-4 generic additional station, digi, mobile, wx, etc
#-5 Other networks (Dstar, Iphones, Androids, Blackberry's etc)
#-6 Special activity, Satellite ops, camping or 6 meters, etc
#-7 walkie talkies, HT's or other human portable
#-8 boats, sailboats, RV's or second main mobile
#-9 Primary Mobile (usually message capable)
#-10 internet, Igates, echolink, winlink, AVRS, APRN, etc
#-11 balloons, aircraft, spacecraft, etc
#-12 APRStt, DTMF, RFID, devices, one-way trackers*, etc
#-13 Weather stations
#-14 Truckers or generally full time drivers
#-15 generic additional station, digi, mobile, wx, etc
# try converting to bytestring if possible type string
try:
callsign = bytes(callsign, 'utf-8')
except:
pass
# we need to do this step to reduce the needed paypload by the callsign ( stripping "-" out of the callsign )
callsign = callsign.split(b'-')
try:
ssid = int(callsign[1])
except:
ssid = 0
#callsign = callsign[0]
#bytestring = bytearray(8)
#bytestring[:len(callsign)] = callsign
#bytestring[7:8] = bytes([ssid])
# ---- callsign with encoding always 6 bytes long
callsign = callsign[0].decode("utf-8")
ssid = bytes([ssid]).decode("utf-8")
return encode_call(callsign + ssid)
#return bytes(bytestring)
def bytes_to_callsign(bytestring):
"""
Convert our callsign, received by a frame to a callsign in a human readable format
Args:
bytestring:
Returns:
bytes
"""
# http://www.aprs.org/aprs11/SSIDs.txt
#-0 Your primary station usually fixed and message capable
#-1 generic additional station, digi, mobile, wx, etc
#-2 generic additional station, digi, mobile, wx, etc
#-3 generic additional station, digi, mobile, wx, etc
#-4 generic additional station, digi, mobile, wx, etc
#-5 Other networks (Dstar, Iphones, Androids, Blackberry's etc)
#-6 Special activity, Satellite ops, camping or 6 meters, etc
#-7 walkie talkies, HT's or other human portable
#-8 boats, sailboats, RV's or second main mobile
#-9 Primary Mobile (usually message capable)
#-10 internet, Igates, echolink, winlink, AVRS, APRN, etc
#-11 balloons, aircraft, spacecraft, etc
#-12 APRStt, DTMF, RFID, devices, one-way trackers*, etc
#-13 Weather stations
#-14 Truckers or generally full time drivers
#-15 generic additional station, digi, mobile, wx, etc
# we need to do this step to reduce the needed paypload by the callsign ( stripping "-" out of the callsign )
'''
callsign = bytes(bytestring[:7])
callsign = callsign.rstrip(b'\x00')
ssid = int.from_bytes(bytes(bytestring[7:8]), "big")
callsign = callsign + b'-'
callsign = callsign.decode('utf-8')
callsign = callsign + str(ssid)
callsign = callsign.encode('utf-8')
return bytes(callsign)
'''
decoded = decode_call(bytestring)
callsign = decoded[:-1]
ssid = ord(bytes(decoded[-1], "utf-8"))
return bytes(callsign + "-" + str(ssid), "utf-8")
def check_callsign(callsign:bytes, crc_to_check:bytes):
"""
Funktion to check a crc against a callsign to calculate the ssid by generating crc until we got it
Args:
callsign: Callsign which we want to check
crc_to_check: The CRC which we want the callsign to check against
Returns:
[True, Callsign + SSID]
False
"""
print(callsign)
try:
callsign = callsign.split(b'-')
callsign = callsign[0] # we want the callsign without SSID
except:
callsign = callsign
for ssid in static.SSID_LIST:
call_with_ssid = bytearray(callsign)
call_with_ssid.extend('-'.encode('utf-8'))
call_with_ssid.extend(str(ssid).encode('utf-8'))
callsign_crc = get_crc_24(call_with_ssid)
if callsign_crc == crc_to_check:
print(call_with_ssid)
return [True, bytes(call_with_ssid)]
return [False, ""]
def encode_grid(grid):
"""
@auther: DB1UJ
Args:
grid:string: maidenhead QTH locater [a-r][a-r][0-9][0-9][a-x][a-x]
Returns:
4 bytes contains 26 bit valid data with encoded grid locator
"""
out_code_word = int(0)
grid = grid.upper() # upper case to be save
int_first = ord(grid[0])-65 # -65 offset for 'A' become zero, utf8 table
int_sec = ord(grid[1])-65 # -65 offset for 'A' become zero, utf8 table
int_val = (int_first * 18) + int_sec # encode for modulo devision, 2 numbers in 1
out_code_word = (int_val & 0b111111111) # only 9 bit LSB A - R * A - R is needed
out_code_word = out_code_word << 9 # shift 9 bit left having space next bits, letter A-R * A-R
int_val = int(grid[2:4]) # number string to number int, highest value 99
out_code_word = out_code_word | (int_val & 0b1111111) # using bit OR to add new value
out_code_word = out_code_word << 7 # shift 7 bit left having space next bits, letter A-X
int_val = ord(grid[4])-65 # -65 offset for 'A' become zero, utf8 table
out_code_word = out_code_word | (int_val & 0b11111) # using bit OR to add new value
out_code_word = out_code_word << 5 # shift 5 bit left having space next bits, letter A-X
int_val = ord(grid[5])-65 # -65 offset for 'A' become zero, utf8 table
out_code_word = out_code_word | (int_val & 0b11111) # using bit OR to add new value
return out_code_word.to_bytes(length=4, byteorder='big')
def decode_grid(b_code_word:bytes):
"""
@auther: DB1UJ
Args:
b_code_word:bytes: 4 bytes with 26 bit valid data LSB
Returns:
grid:str: upper case maidenhead QTH locater [A-R][A-R][0-9][0-9][A-X][A-X]
"""
code_word = int.from_bytes(b_code_word, byteorder='big', signed=False)
grid = chr((code_word & 0b11111) + 65)
code_word = code_word >> 5
grid = chr((code_word & 0b11111) + 65) + grid
code_word = code_word >> 7
grid = str(int(code_word & 0b1111111)) + grid
if (code_word & 0b1111111) < 10:
grid = '0' + grid
code_word = code_word >> 9
int_val = int(code_word & 0b111111111)
int_first = int_val // 18
int_sec = int_val % 18
grid = chr(int(int_first)+65) + chr(int(int_sec)+65) + grid
return grid
def encode_call(call):
"""
@auther: DB1UJ
Args:
call:string: ham radio call sign [A-Z,0-9], last char SSID 0-63
Returns:
6 bytes contains 6 bits/sign encoded 8 char call sign with binary SSID (only upper letters + numbers, SSID)
"""
out_code_word = int(0)
call = call.upper() # upper case to be save
for x in call:
int_val = ord(x)-48 # -48 reduce bits, begin with first number utf8 table
out_code_word = out_code_word << 6 # shift left 6 bit, making space for a new char
out_code_word = out_code_word | (int_val & 0b111111) # bit OR adds the new char, masked with AND 0b111111
out_code_word = out_code_word >> 6 # clean last char
out_code_word = out_code_word << 6 # make clean space
out_code_word = out_code_word | (ord(call[-1]) & 0b111111) # add the SSID uncoded only 0 - 63
return out_code_word.to_bytes(length=6, byteorder='big')
def decode_call(b_code_word:bytes):
"""
@auther: DB1UJ
Args:
b_code_word:bytes: 6 bytes with 6 bits/sign valid data char signs LSB
Returns:
call:str: upper case ham radio call sign [A-Z,0-9] + binary SSID
"""
code_word = int.from_bytes(b_code_word, byteorder='big', signed=False)
ssid = chr(code_word & 0b111111) # save the uncoded binary SSID
call = str()
while code_word != 0:
call = chr((code_word & 0b111111)+48) + call
code_word = code_word >> 6
call = call[0:-1] + ssid # remove the last char from call and replace with SSID
return call