kopia lustrzana https://github.com/projecthorus/wenet
107 wiersze
2.8 KiB
Python
107 wiersze
2.8 KiB
Python
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#!/usr/bin/env python2.7
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#
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# Wenet Packet Generators / Decoders
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#
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import struct
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WENET_IMAGE_UDP_PORT = 7890
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WENET_TELEMETRY_UDP_PORT = 7891
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class WENET_PACKET_TYPES:
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TEXT_MESSAGE = 0x00
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TELEMETRY = 0x01
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# Your packet types here!
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SSDV = 0x55
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def decode_packet_type(packet):
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# Convert packet to a list of integers before parsing.
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packet = list(bytearray(packet))
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return packet[0]
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def packet_to_string(packet):
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packet_type = decode_packet_type(packet)
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if packet_type == WENET_PACKET_TYPES.TEXT_MESSAGE:
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return text_message_string(packet)
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elif packet_type == WENET_PACKET_TYPES.TELEMETRY:
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return telemetry_string(packet)
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elif packet_type == WENET_PACKET_TYPES.SSDV:
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return ssdv_packet_string(packet)
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else:
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return "Unknown Packet Type: %d" % packet_type
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#
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# SSDV - Packets as per https://ukhas.org.uk/guides:ssdv
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#
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def ssdv_packet_info(packet):
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""" Extract various information out of a SSDV packet, and present as a dict. """
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packet = list(bytearray(packet))
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# Check packet is actually a SSDV packet.
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if len(packet) != 256:
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return {'error': "ERROR: Invalid Packet Length"}
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if packet[0] != 0x55: # A first byte of 0x55 indicates a SSDV packet.
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return {'error': "ERROR: Not a SSDV Packet."}
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# We got this far, may as well try and extract the packet info.
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try:
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packet_info = {
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'callsign' : "???", # TODO: Callsign decoding.
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'packet_type' : "FEC" if (packet[1]==0x66) else "No-FEC",
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'image_id' : packet[6],
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'packet_id' : (packet[7]<<8) + packet[8],
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'width' : packet[9]*16,
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'height' : packet[10]*16,
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'error' : "None"
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}
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return packet_info
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except Exception as e:
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return {'error': "ERROR: %s" % str(e)}
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def ssdv_packet_string(packet):
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""" Produce a textual representation of a SSDV packet. """
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packet_info = ssdv_packet_info(packet)
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if packet_info['error'] != 'None':
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return "SSDV: Unable to decode."
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else:
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return "SSDV: %s, Img:%d, Pkt:%d, %dx%d" % (packet_info['packet_type'],packet_info['image_id'],packet_info['packet_id'],packet_info['width'],packet_info['height'])
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#
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# Text Messages
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#
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def decode_text_message(packet):
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""" Extract information from a text message packet """
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# We need the packet as a string, convert to a string in case we were passed a list of bytes.
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packet = str(bytearray(packet))
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message = {}
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try:
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message['len'] = struct.unpack("B",packet[1])[0]
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message['id'] = struct.unpack(">H",packet[2:4])[0]
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message['text'] = packet[4:4+message['len']]
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message['error'] = 'None'
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except:
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return {'error': 'Could not decode message packet.'}
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return message
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def text_message_string(packet):
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message = decode_text_message(packet)
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if message['error'] != 'None':
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return "Text: ERROR Could not decode."
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else:
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return "Text Message #%d: \t%s" % (message['id'],message['text'])
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#
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# GPS/IMU Telemetry
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#
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def telemetry_string(packet):
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return "Not Implemented."
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