FreeDATA/tnc/helpers.py
Paul Kronenwetter bc6db3950f Suppress expected exceptions.
Fixes issue #196.
2022-05-29 09:47:11 -04:00

431 lines
12 KiB
Python

# -*- coding: utf-8 -*-
"""
Created on Fri Dec 25 21:25:14 2020
@author: DJ2LS
"""
import time
import crcengine
import static
import structlog
log = structlog.get_logger(__file__)
def wait(seconds: float) -> bool:
"""
Args:
seconds:
Returns:
"""
timeout = time.time() + seconds
while time.time() < timeout:
time.sleep(0.01)
return True
def get_crc_8(data) -> bytes:
"""Author: DJ2LS
Get the CRC8 of a byte string
param: data = bytes()
Args:
data:
Returns:
CRC-8 (CCITT) of the provided data as bytes
"""
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) -> bytes:
"""Author: DJ2LS
Get the CRC16 of a byte string
param: data = bytes()
Args:
data:
Returns:
CRC-16 (CCITT) of the provided data as bytes
"""
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) -> bytes:
"""Author: DJ2LS
Get the CRC24-OPENPGP of a byte string
https://github.com/GardenTools/CrcEngine#examples
param: data = bytes()
Args:
data:
Returns:
CRC-24 (OpenPGP) of the provided data as bytes
"""
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: bytes) -> bytes:
"""Author: DJ2LS
Get the CRC32 of a byte string
param: data = bytes()
Args:
data:
Returns:
CRC-32 of the provided data as bytes
"""
crc_algorithm = crcengine.new("crc32") # load crc32 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:
Nothing
"""
# 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(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) -> bytes:
"""
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 TypeError:
# This is expected depending on the type of the `callsign` argument.
# log.debug("[HLP] callsign_to_bytes: Error converting callsign to bytes:", e=err)
pass
except Exception as err:
log.debug("[HLP] callsign_to_bytes: Error callsign SSID to integer:", e=err)
# Need this step to reduce the needed payload by the callsign
# (stripping "-" out of the callsign)
callsign = callsign.split(b"-")
ssid = 0
try:
ssid = int(callsign[1])
except IndexError:
# This is expected when callsign doesn't have a dash.
# log.debug("[HLP] callsign_to_bytes: Error callsign SSID to integer:", e=err)
pass
except Exception as err:
log.debug("[HLP] callsign_to_bytes: Error callsign SSID to integer:", e=err)
# 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: bytes) -> bytes:
"""
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(f"{callsign}-{ssid}", "utf-8")
def check_callsign(callsign: bytes, crc_to_check: bytes):
"""
Function to check a crc against a callsign to calculate the
ssid by generating crc until we find the correct SSID
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)
log.debug("[HLP] check_callsign: Checking:", callsign=callsign)
try:
# We want the callsign without SSID
callsign = callsign.split(b"-")[0]
except IndexError:
# This is expected when `callsign` doesn't have a dash.
pass
except Exception as err:
log.debug("[HLP] check_callsign: Error callsign SSID to integer:", e=err)
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):
"""
@author: 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 = 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 <<= 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 |= int_val & 0b1111111 # using bit OR to add new value
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 |= int_val & 0b11111 # using bit OR to add new value
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 |= 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):
"""
@author: 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 >>= 5
grid = chr((code_word & 0b11111) + 65) + grid
code_word >>= 7
grid = str(int(code_word & 0b1111111)) + grid
if (code_word & 0b1111111) < 10:
grid = f"0{grid}"
code_word >>= 9
int_val = int(code_word & 0b111111111)
int_first, int_sec = divmod(int_val, 18)
# 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):
"""
@author: 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 = 0
call = call.upper() # upper case to be save
for char in call:
int_val = ord(char) - 48 # -48 reduce bits, begin with first number utf8 table
out_code_word <<= 6 # shift left 6 bit, making space for a new char
out_code_word |= (
int_val & 0b111111
) # bit OR adds the new char, masked with AND 0b111111
out_code_word >>= 6 # clean last char
out_code_word <<= 6 # make clean space
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):
"""
@author: 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 >>= 6
call = call[:-1] + ssid # remove the last char from call and replace with SSID
return call