openwebrx-clone/owrx/kiss.py
2019-08-11 18:42:41 +02:00

142 lines
4.4 KiB
Python

import socket
import time
from owrx.map import Map, LatLngLocation
import logging
logger = logging.getLogger(__name__)
FEND = 0xC0
FESC = 0xDB
TFEND = 0xDC
TFESC = 0XDD
def group(a, *ns):
for n in ns:
a = [a[i:i+n] for i in range(0, len(a), n)]
return a
def join(a, *cs):
return [cs[0].join(join(t, *cs[1:])) for t in a] if cs else a
def hexdump(data):
toHex = lambda c: '{:02X}'.format(c)
toChr = lambda c: chr(c) if 32 <= c < 127 else '.'
make = lambda f, *cs: join(group(list(map(f, data)), 8, 2), *cs)
hs = make(toHex, ' ', ' ')
cs = make(toChr, ' ', '')
for i, (h, c) in enumerate(zip(hs, cs)):
print ('{:010X}: {:48} {:16}'.format(i * 16, h, c))
class KissClient(object):
def __init__(self, port):
time.sleep(1)
self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.socket.connect(("localhost", port))
def read(self):
buf = bytes()
escaped = False
while True:
input = self.socket.recv(1)
# EOF
if len(input) == 0:
return bytes()
if input[0] == FESC:
escaped = True
elif escaped:
if input[0] == TFEND:
buf += [FEND]
elif input[0] == TFESC:
buf += [FESC]
else:
logger.warning("invalid escape char: %s", str(input[0]))
escaped = False
elif input[0] == FEND:
logger.debug("decoded frame: " + str(buf))
if len(buf) > 0:
try:
return self.parseFrame(buf)
except Exception:
logger.exception("failed to decode packet data")
return {}
else:
buf += input
def parseFrame(self, frame):
# data frames start with 0x00
if frame[0] != 0x00:
return {}
ax25frame = frame[1:]
control_pid = ax25frame.find(bytes([0x03, 0xf0]))
if control_pid % 7 > 0:
logger.warning("aprs packet framing error: control/pid position not aligned with 7-octet callsign data")
def chunks(l, n):
"""Yield successive n-sized chunks from l."""
for i in range(0, len(l), n):
yield l[i:i + n]
information = ax25frame[control_pid+2:]
# TODO how can we tell if this is an APRS frame at all?
aprsData = self.parseAprsData(information)
data = {
"destination": self.extractCallsign(ax25frame[0:7]),
"source": self.extractCallsign(ax25frame[7:14]),
"path": [self.extractCallsign(c) for c in chunks(ax25frame[14:control_pid], 7)]
}
data.update(aprsData)
logger.debug(data)
if "lat" in data and "lon" in data:
loc = LatLngLocation(data["lat"], data["lon"], data["comment"] if "comment" in data else None)
Map.getSharedInstance().updateLocation(data["source"], loc, "APRS")
return data
def parseAprsData(self, data):
#hexdump(data)
# TODO detect MIC-E frame and decode accordingly
data = data.decode()
logger.debug(data)
def parseCoordinates(raw):
# TODO parse N/S and E/W
return {
"lat": int(raw[0:2]) + float(raw[2:7]) / 60,
"lon": int(raw[9:12]) + float(raw[12:17]) / 60
}
if data[0] == "!":
# fixed
coords = parseCoordinates(data[1:19])
coords["comment"] = data[20:]
return coords
elif data[0] == "/":
# APRS TNC
coords = parseCoordinates(data[8:26])
coords["comment"] = data[27:]
return coords
elif data[0] == "@":
# MOBILE
# TODO CSE, SPD, BRG, 90Q, comments
if data[26] == "\\":
# DF
return parseCoordinates(data[8:26])
coords = parseCoordinates(data[8:26])
coords["symbol"] = data[26]
coords["comment"] = data[27:]
return coords
return {}
def extractCallsign(self, input):
cs = bytes([b >> 1 for b in input[0:6]]).decode().strip()
ssid = (input[6] & 0b00011110) >> 1
if ssid > 0:
return "{callsign}-{ssid}".format(callsign=cs, ssid=ssid)
else:
return cs