mirror of
https://github.com/DJ2LS/FreeDATA
synced 2024-05-14 08:04:33 +00:00
430 lines
15 KiB
Python
430 lines
15 KiB
Python
from modem_frametypes import FRAME_TYPE as FR_TYPE
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import helpers
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import codec2
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class DataFrameFactory:
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LENGTH_SIG0_FRAME = 14
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LENGTH_SIG1_FRAME = 14
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"""
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helpers.set_flag(byte, 'DATA-ACK-NACK', True, FLAG_POSITIONS)
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helpers.get_flag(byte, 'DATA-ACK-NACK', FLAG_POSITIONS)
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"""
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ARQ_FLAGS = {
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'FINAL': 0, # Bit-position for indicating the FINAL state
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'ABORT': 1, # Bit-position for indicating the ABORT request
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'CHECKSUM': 2, # Bit-position for indicating the CHECKSUM is correct or not
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}
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def __init__(self, config):
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self.myfullcall = f"{config['STATION']['mycall']}-{config['STATION']['myssid']}"
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self.mygrid = config['STATION']['mygrid']
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# table for holding our frame templates
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self.template_list = {}
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self._load_broadcast_templates()
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self._load_ping_templates()
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self._load_fec_templates()
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self._load_arq_templates()
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def _load_broadcast_templates(self):
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# cq frame
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self.template_list[FR_TYPE.CQ.value] = {
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"frame_length": self.LENGTH_SIG0_FRAME,
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"origin": 6,
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"gridsquare": 4
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}
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# qrv frame
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self.template_list[FR_TYPE.QRV.value] = {
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"frame_length": self.LENGTH_SIG0_FRAME,
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"origin": 6,
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"gridsquare": 4,
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"snr": 1
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}
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# beacon frame
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self.template_list[FR_TYPE.BEACON.value] = {
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"frame_length": self.LENGTH_SIG0_FRAME,
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"origin": 6,
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"gridsquare": 4
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}
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def _load_ping_templates(self):
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# ping frame
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self.template_list[FR_TYPE.PING.value] = {
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"frame_length": self.LENGTH_SIG0_FRAME,
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"destination_crc": 3,
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"origin_crc": 3,
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"origin": 6
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}
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# ping ack
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self.template_list[FR_TYPE.PING_ACK.value] = {
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"frame_length": self.LENGTH_SIG0_FRAME,
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"destination_crc": 3,
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"origin_crc": 3,
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"gridsquare": 4,
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"snr": 1,
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}
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def _load_fec_templates(self):
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# fec wakeup frame
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self.template_list[FR_TYPE.FEC_WAKEUP.value] = {
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"frame_length": self.LENGTH_SIG0_FRAME,
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"origin": 6,
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"mode": 1,
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"n_bursts": 1,
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}
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# fec frame
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self.template_list[FR_TYPE.FEC.value] = {
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"frame_length": self.LENGTH_SIG0_FRAME,
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"data": self.LENGTH_SIG0_FRAME - 1
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}
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# fec is writing frame
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self.template_list[FR_TYPE.IS_WRITING.value] = {
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"frame_length": self.LENGTH_SIG0_FRAME,
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"origin": 6
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}
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def _load_arq_templates(self):
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self.template_list[FR_TYPE.ARQ_SESSION_OPEN.value] = {
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"frame_length": self.LENGTH_SIG0_FRAME,
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"destination_crc": 3,
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"origin": 6,
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"session_id": 1,
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"maximum_bandwidth": 2,
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}
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self.template_list[FR_TYPE.ARQ_SESSION_OPEN_ACK.value] = {
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"frame_length": self.LENGTH_SIG0_FRAME,
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"session_id": 1,
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"origin": 6,
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"destination_crc": 3,
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"version": 1,
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"snr": 1,
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"flag": 1,
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}
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self.template_list[FR_TYPE.ARQ_SESSION_INFO.value] = {
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"frame_length": self.LENGTH_SIG0_FRAME,
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"session_id": 1,
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"total_length": 4,
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"total_crc": 4,
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"snr": 1,
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"flag": 1,
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"type": 1,
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}
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self.template_list[FR_TYPE.ARQ_SESSION_INFO_ACK.value] = {
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"frame_length": self.LENGTH_SIG0_FRAME,
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"session_id": 1,
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"total_crc": 4,
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"snr": 1,
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"speed_level": 1,
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"frames_per_burst": 1,
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"flag": 1,
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}
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self.template_list[FR_TYPE.ARQ_STOP.value] = {
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"frame_length": self.LENGTH_SIG0_FRAME,
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"session_id": 1,
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}
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self.template_list[FR_TYPE.ARQ_STOP_ACK.value] = {
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"frame_length": self.LENGTH_SIG0_FRAME,
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"session_id": 1,
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}
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# arq burst frame
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self.template_list[FR_TYPE.ARQ_BURST_FRAME.value] = {
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"frame_length": None,
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"session_id": 1,
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"speed_level": 1,
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"offset": 4,
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"data": "dynamic",
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}
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# arq burst ack
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self.template_list[FR_TYPE.ARQ_BURST_ACK.value] = {
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"frame_length": self.LENGTH_SIG1_FRAME,
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"session_id": 1,
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"offset":4,
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"speed_level": 1,
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"frames_per_burst": 1,
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"snr": 1,
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"flag": 1,
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}
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def construct(self, frametype, content, frame_length = LENGTH_SIG1_FRAME):
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frame_template = self.template_list[frametype.value]
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if isinstance(frame_template["frame_length"], int):
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frame_length = frame_template["frame_length"]
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else:
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frame_length -= 2
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frame = bytearray(frame_length)
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frame[:1] = bytes([frametype.value])
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buffer_position = 1
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for key, item_length in frame_template.items():
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if key == "frame_length":
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continue
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if not isinstance(item_length, int):
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item_length = len(content[key])
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if buffer_position + item_length > frame_length:
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raise OverflowError("Frame data overflow!")
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frame[buffer_position: buffer_position + item_length] = content[key]
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buffer_position += item_length
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return frame
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def deconstruct(self, frame):
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buffer_position = 1
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# Extract frametype and get the corresponding template
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frametype = int.from_bytes(frame[:1], "big")
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frame_template = self.template_list.get(frametype)
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if not frame_template:
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# Handle the case where the frame type is not recognized
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raise ValueError(f"Unknown frame type: {frametype}")
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extracted_data = {"frame_type": FR_TYPE(frametype).name, "frame_type_int": frametype}
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for key, item_length in frame_template.items():
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if key == "frame_length":
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continue
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# data is always on the last payload slots
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if item_length in ["dynamic"] and key in["data"]:
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data = frame[buffer_position:-2]
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item_length = len(data)
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else:
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data = frame[buffer_position: buffer_position + item_length]
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# Process the data based on the key
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if key in ["origin", "destination"]:
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extracted_data[key] = helpers.bytes_to_callsign(data).decode()
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elif key in ["origin_crc", "destination_crc", "total_crc"]:
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extracted_data[key] = data.hex()
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elif key == "gridsquare":
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extracted_data[key] = helpers.decode_grid(data)
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elif key in ["session_id", "speed_level",
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"frames_per_burst", "version",
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"offset", "total_length", "state", "type", "maximum_bandwidth"]:
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extracted_data[key] = int.from_bytes(data, 'big')
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elif key in ["snr"]:
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extracted_data[key] = helpers.snr_from_bytes(data)
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elif key == "flag":
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data = int.from_bytes(data, "big")
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extracted_data[key] = {}
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# check for frametype for selecting the correspinding flag dictionary
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if frametype in [FR_TYPE.ARQ_SESSION_OPEN_ACK.value, FR_TYPE.ARQ_SESSION_INFO_ACK.value, FR_TYPE.ARQ_BURST_ACK.value]:
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flag_dict = self.ARQ_FLAGS
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for flag in flag_dict:
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# Update extracted_data with the status of each flag
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# get_flag returns True or False based on the bit value at the flag's position
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extracted_data[key][flag] = helpers.get_flag(data, flag, flag_dict)
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else:
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extracted_data[key] = data
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buffer_position += item_length
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return extracted_data
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def get_bytes_per_frame(self, mode: codec2.FREEDV_MODE) -> int:
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freedv = codec2.open_instance(mode.value)
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bytes_per_frame = int(codec2.api.freedv_get_bits_per_modem_frame(freedv) / 8)
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return bytes_per_frame
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def get_available_data_payload_for_mode(self, type: FR_TYPE, mode:codec2.FREEDV_MODE):
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whole_frame_length = self.get_bytes_per_frame(mode)
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available = whole_frame_length - 2 # 2Bytes CRC16
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available -= 1 # Frame Type
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for field, length in self.template_list[type.value].items():
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if field != 'frame_length' and isinstance(length, int):
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available -= length
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return available
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def build_ping(self, destination):
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payload = {
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"destination_crc": helpers.get_crc_24(destination),
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"origin_crc": helpers.get_crc_24(self.myfullcall),
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"origin": helpers.callsign_to_bytes(self.myfullcall),
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}
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return self.construct(FR_TYPE.PING, payload)
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def build_ping_ack(self, destination, snr):
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payload = {
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"destination_crc": helpers.get_crc_24(destination),
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"origin_crc": helpers.get_crc_24(self.myfullcall),
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"gridsquare": helpers.encode_grid(self.mygrid),
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"snr": helpers.snr_to_bytes(snr)
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}
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return self.construct(FR_TYPE.PING_ACK, payload)
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def build_cq(self):
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payload = {
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"origin": helpers.callsign_to_bytes(self.myfullcall),
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"gridsquare": helpers.encode_grid(self.mygrid)
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}
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return self.construct(FR_TYPE.CQ, payload)
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def build_qrv(self, snr):
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payload = {
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"origin": helpers.callsign_to_bytes(self.myfullcall),
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"gridsquare": helpers.encode_grid(self.mygrid),
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"snr": helpers.snr_to_bytes(snr)
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}
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return self.construct(FR_TYPE.QRV, payload)
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def build_beacon(self):
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payload = {
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"origin": helpers.callsign_to_bytes(self.myfullcall),
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"gridsquare": helpers.encode_grid(self.mygrid)
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}
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return self.construct(FR_TYPE.BEACON, payload)
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def build_fec_is_writing(self):
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payload = {
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"origin": helpers.callsign_to_bytes(self.myfullcall),
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}
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return self.construct(FR_TYPE.IS_WRITING, payload)
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def build_fec_wakeup(self, mode):
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mode_int = codec2.freedv_get_mode_value_by_name(mode)
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payload = {
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"origin": helpers.callsign_to_bytes(self.myfullcall),
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"mode": bytes([mode_int]),
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"n_bursts": bytes([1]) # n payload bursts,
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}
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return self.construct(FR_TYPE.FEC_WAKEUP, payload)
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def build_fec(self, mode, payload):
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mode_int = codec2.freedv_get_mode_value_by_name(mode)
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payload_per_frame = codec2.get_bytes_per_frame(mode_int) - 2
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fec_payload_length = payload_per_frame - 1
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fec_frame = bytearray(payload_per_frame)
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fec_frame[:1] = bytes([FR_TYPE.FEC.value])
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fec_frame[1:payload_per_frame] = bytes(payload[:fec_payload_length])
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return fec_frame
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def build_test(self):
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test_frame = bytearray(126)
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test_frame[:1] = bytes([FR_TYPE.TEST_FRAME.value])
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return test_frame
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def build_arq_session_open(self, destination, session_id, maximum_bandwidth):
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payload = {
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"destination_crc": helpers.get_crc_24(destination),
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"origin": helpers.callsign_to_bytes(self.myfullcall),
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"session_id": session_id.to_bytes(1, 'big'),
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"maximum_bandwidth": maximum_bandwidth.to_bytes(2, 'big'),
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}
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return self.construct(FR_TYPE.ARQ_SESSION_OPEN, payload)
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def build_arq_session_open_ack(self, session_id, destination, version, snr, flag_abort=False):
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flag = 0b00000000
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if flag_abort:
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flag = helpers.set_flag(flag, 'ABORT', True, self.ARQ_FLAGS)
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payload = {
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"session_id": session_id.to_bytes(1, 'big'),
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"origin": helpers.callsign_to_bytes(self.myfullcall),
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"destination_crc": helpers.get_crc_24(destination),
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"version": bytes([version]),
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"snr": helpers.snr_to_bytes(1),
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"flag": flag.to_bytes(1, 'big'),
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}
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return self.construct(FR_TYPE.ARQ_SESSION_OPEN_ACK, payload)
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def build_arq_session_info(self, session_id: int, total_length: int, total_crc: bytes, snr, type):
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flag = 0b00000000
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payload = {
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"session_id": session_id.to_bytes(1, 'big'),
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"total_length": total_length.to_bytes(4, 'big'),
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"total_crc": total_crc,
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"snr": helpers.snr_to_bytes(1),
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"flag": flag.to_bytes(1, 'big'),
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"type": type.to_bytes(1, 'big'),
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}
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return self.construct(FR_TYPE.ARQ_SESSION_INFO, payload)
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def build_arq_stop(self, session_id: int):
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payload = {
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"session_id": session_id.to_bytes(1, 'big'),
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}
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return self.construct(FR_TYPE.ARQ_STOP, payload)
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def build_arq_stop_ack(self, session_id: int):
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payload = {
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"session_id": session_id.to_bytes(1, 'big'),
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}
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return self.construct(FR_TYPE.ARQ_STOP_ACK, payload)
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def build_arq_session_info_ack(self, session_id, total_crc, snr, speed_level, frames_per_burst, flag_final=False, flag_abort=False):
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flag = 0b00000000
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if flag_final:
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flag = helpers.set_flag(flag, 'FINAL', True, self.ARQ_FLAGS)
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if flag_abort:
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flag = helpers.set_flag(flag, 'ABORT', True, self.ARQ_FLAGS)
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payload = {
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"frame_length": self.LENGTH_SIG0_FRAME,
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"session_id": session_id.to_bytes(1, 'big'),
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"total_crc": bytes.fromhex(total_crc),
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"snr": helpers.snr_to_bytes(1),
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"speed_level": speed_level.to_bytes(1, 'big'),
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"frames_per_burst": frames_per_burst.to_bytes(1, 'big'),
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"flag": flag.to_bytes(1, 'big'),
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}
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return self.construct(FR_TYPE.ARQ_SESSION_INFO_ACK, payload)
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def build_arq_burst_frame(self, freedv_mode: codec2.FREEDV_MODE, session_id: int, offset: int, data: bytes, speed_level: int):
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payload = {
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"session_id": session_id.to_bytes(1, 'big'),
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"speed_level": speed_level.to_bytes(1, 'big'),
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"offset": offset.to_bytes(4, 'big'),
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"data": data,
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}
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frame = self.construct(FR_TYPE.ARQ_BURST_FRAME, payload, self.get_bytes_per_frame(freedv_mode))
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return frame
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def build_arq_burst_ack(self, session_id: bytes, offset, speed_level: int,
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frames_per_burst: int, snr: int, flag_final=False, flag_checksum=False, flag_abort=False):
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flag = 0b00000000
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if flag_final:
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flag = helpers.set_flag(flag, 'FINAL', True, self.ARQ_FLAGS)
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if flag_checksum:
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flag = helpers.set_flag(flag, 'CHECKSUM', True, self.ARQ_FLAGS)
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if flag_abort:
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flag = helpers.set_flag(flag, 'ABORT', True, self.ARQ_FLAGS)
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payload = {
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"session_id": session_id.to_bytes(1, 'big'),
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"offset": offset.to_bytes(4, 'big'),
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"speed_level": speed_level.to_bytes(1, 'big'),
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"frames_per_burst": frames_per_burst.to_bytes(1, 'big'),
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"snr": helpers.snr_to_bytes(snr),
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"flag": flag.to_bytes(1, 'big'),
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}
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return self.construct(FR_TYPE.ARQ_BURST_ACK, payload)
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