openwebrx-clone/owrx/kiss.py

65 lines
1.8 KiB
Python

import socket
import time
import logging
import random
logger = logging.getLogger(__name__)
FEND = 0xC0
FESC = 0xDB
TFEND = 0xDC
TFESC = 0xDD
class KissClient(object):
@staticmethod
def getFreePort():
# direwolf has some strange hardcoded port ranges
while True:
try:
port = random.randrange(1024, 49151)
# test if port is available for use
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind(('localhost', port))
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.close()
return port
except OSError:
pass
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):
return self.socket.recv(1)
class KissDeframer(object):
def __init__(self):
self.escaped = False
self.buf = bytearray()
def parse(self, input):
frames = []
for b in input:
if b == FESC:
self.escaped = True
elif self.escaped:
if b == TFEND:
self.buf.append(FEND)
elif b == TFESC:
self.buf.append(FESC)
else:
logger.warning("invalid escape char: %s", str(input[0]))
self.escaped = False
elif input[0] == FEND:
# data frames start with 0x00
if len(self.buf) > 1 and self.buf[0] == 0x00:
frames += [self.buf[1:]]
self.buf = bytearray()
else:
self.buf.append(b)
return frames