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#!/usr/bin/env python |
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# -*- coding: utf-8 -*- |
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"""KISS Core Classes.""" |
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# These imports are for python3 compatibility inside python2 |
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from __future__ import absolute_import |
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from __future__ import division |
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from __future__ import print_function |
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import logging |
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import threading |
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from abc import ABCMeta |
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from abc import abstractmethod |
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from six import with_metaclass |
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from apex.kiss import constants as kiss_constants |
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__author__ = 'Jeffrey Phillips Freeman (WI2ARD)' |
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__maintainer__ = 'Jeffrey Phillips Freeman (WI2ARD)' |
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__email__ = '[email protected]' |
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__license__ = 'Apache License, Version 2.0' |
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__copyright__ = 'Copyright 2016, Syncleus, Inc. and contributors' |
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__credits__ = [] |
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class Kiss(with_metaclass(ABCMeta, object)): |
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"""Abstract KISS Object Class.""" |
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logger = logging.getLogger(__name__) |
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logger.setLevel(kiss_constants.LOG_LEVEL) |
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console_handler = logging.StreamHandler() |
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console_handler.setLevel(kiss_constants.LOG_LEVEL) |
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formatter = logging.Formatter(kiss_constants.LOG_FORMAT) |
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console_handler.setFormatter(formatter) |
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logger.addHandler(console_handler) |
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logger.propagate = False |
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frame_buffer = [] |
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def __init__(self, strip_df_start=True): |
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self.strip_df_start = strip_df_start |
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self.exit_kiss = False |
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self.lock = threading.Lock() |
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@staticmethod |
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def __strip_df_start(frame): |
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""" |
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Strips KISS DATA_FRAME start (0x00) and newline from frame. |
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:param frame: APRS/AX.25 frame. |
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:type frame: str |
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:returns: APRS/AX.25 frame sans DATA_FRAME start (0x00). |
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:rtype: str |
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""" |
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while frame[0] is kiss_constants.DATA_FRAME: |
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del frame[0] |
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while chr(frame[0]).isspace(): |
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del frame[0] |
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while chr(frame[-1]).isspace(): |
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del frame[-1] |
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return frame |
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@staticmethod |
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def __escape_special_codes(raw_code_bytes): |
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""" |
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Escape special codes, per KISS spec. |
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"If the FEND or FESC codes appear in the data to be transferred, they |
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need to be escaped. The FEND code is then sent as FESC, TFEND and the |
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FESC is then sent as FESC, TFESC." |
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- http://en.wikipedia.org/wiki/KISS_(TNC)#Description |
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""" |
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encoded_bytes = [] |
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for raw_code_byte in raw_code_bytes: |
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if raw_code_byte is kiss_constants.FESC: |
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encoded_bytes += kiss_constants.FESC_TFESC |
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elif raw_code_byte is kiss_constants.FEND: |
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encoded_bytes += kiss_constants.FESC_TFEND |
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else: |
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encoded_bytes += [raw_code_byte] |
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return encoded_bytes |
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@staticmethod |
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def __command_byte_combine(port, command_code): |
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""" |
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Constructs the command byte for the tnc which includes the tnc port and command code. |
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:param port: integer from 0 to 127 indicating the TNC port |
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:type port: int |
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:param command_code: A command code constant, a value from 0 to 127 |
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:type command_code: int |
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:return: An integer combining the two values into a single byte |
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""" |
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if port > 127 or port < 0: |
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raise Exception('port out of range') |
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elif command_code > 127 or command_code < 0: |
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raise Exception('command_Code out of range') |
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return (port << 4) & command_code |
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@abstractmethod |
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def _read_interface(self): |
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pass |
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@abstractmethod |
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def _write_interface(self, data): |
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pass |
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def connect(self, mode_init=None, **kwargs): |
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""" |
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Initializes the KISS device and commits configuration. |
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This method is abstract and must be implemented by a concrete class. |
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See http://en.wikipedia.org/wiki/KISS_(TNC)#Command_codes |
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for configuration names. |
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:param **kwargs: name/value pairs to use as initial config values. |
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""" |
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pass |
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def close(self): |
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if self.exit_kiss is True: |
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self._write_interface(kiss_constants.MODE_END) |
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def _write_setting(self, name, value): |
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""" |
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Writes KISS Command Codes to attached device. |
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http://en.wikipedia.org/wiki/KISS_(TNC)#Command_Codes |
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:param name: KISS Command Code Name as a string. |
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:param value: KISS Command Code Value to write. |
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""" |
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self.logger.debug('Configuring %s = %s', name, repr(value)) |
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# Do the reasonable thing if a user passes an int |
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if isinstance(value, int): |
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value = chr(value) |
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return self._write_interface( |
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[kiss_constants.FEND] + |
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[getattr(kiss_constants, name.upper())] + |
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[Kiss.__escape_special_codes(value)] + |
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[kiss_constants.FEND] |
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) |
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def __fill_buffer(self): |
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""" |
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Reads any pending data in the interface and stores it in the frame_buffer |
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""" |
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new_frames = [] |
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read_buffer = [] |
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read_data = self._read_interface() |
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while read_data is not None and len(read_data): |
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split_data = [[]] |
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for read_byte in read_data: |
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if read_byte is kiss_constants.FEND: |
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split_data.append([]) |
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else: |
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split_data[-1].append(read_byte) |
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len_fend = len(split_data) |
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# No FEND in frame |
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if len_fend == 1: |
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read_buffer += split_data[0] |
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# Single FEND in frame |
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elif len_fend == 2: |
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# Closing FEND found |
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if split_data[0]: |
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# Partial frame continued, otherwise drop |
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new_frames.append(read_buffer + split_data[0]) |
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read_buffer = [] |
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# Opening FEND found |
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else: |
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new_frames.append(read_buffer) |
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read_buffer = split_data[1] |
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# At least one complete frame received |
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elif len_fend >= 3: |
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for i in range(0, len_fend - 1): |
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read_buffer_tmp = read_buffer + split_data[i] |
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if len(read_buffer_tmp) is not 0: |
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new_frames.append(read_buffer_tmp) |
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read_buffer = [] |
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if split_data[len_fend - 1]: |
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read_buffer = split_data[len_fend - 1] |
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# Get anymore data that is waiting |
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read_data = self._read_interface() |
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for new_frame in new_frames: |
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if len(new_frame) and new_frame[0] == 0: |
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if self.strip_df_start: |
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new_frame = Kiss.__strip_df_start(new_frame) |
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self.frame_buffer.append(new_frame) |
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def read(self): |
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with self.lock: |
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if not len(self.frame_buffer): |
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self.__fill_buffer() |
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if len(self.frame_buffer): |
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return_frame = self.frame_buffer[0] |
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del self.frame_buffer[0] |
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return return_frame |
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else: |
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return None |
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def write(self, frame_bytes, port=0): |
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""" |
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Writes frame to KISS interface. |
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:param frame: Frame to write. |
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""" |
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with self.lock: |
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kiss_packet = [kiss_constants.FEND] + [Kiss.__command_byte_combine(port, kiss_constants.DATA_FRAME)] + \ |
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Kiss.__escape_special_codes(frame_bytes) + [kiss_constants.FEND] |
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return self._write_interface(kiss_packet) |
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