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299 lines
11 KiB
Python
299 lines
11 KiB
Python
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# MIT License - Copyright (c) 2024 Mark Qvist / unsigned.io
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# This example illustrates creating a custom interface
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# definition, that can be loaded and used by Reticulum at
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# runtime. Any number of custom interfaces can be created
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# and loaded. To use the interface place it in the folder
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# ~/.reticulum/interfaces, and add an interface entry to
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# your Reticulum configuration file similar to this:
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# [[Example Custom Interface]]
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# type = ExampleInterface
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# enabled = no
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# mode = gateway
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# port = /dev/ttyUSB0
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# speed = 115200
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# databits = 8
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# parity = none
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# stopbits = 1
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from time import sleep
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import sys
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import threading
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import time
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# This HDLC helper class is used by the interface
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# to delimit and packetize data over the physical
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# medium - in this case a serial connection.
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class HDLC():
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# This example interface packetizes data using
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# simplified HDLC framing, similar to PPP
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FLAG = 0x7E
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ESC = 0x7D
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ESC_MASK = 0x20
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@staticmethod
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def escape(data):
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data = data.replace(bytes([HDLC.ESC]), bytes([HDLC.ESC, HDLC.ESC^HDLC.ESC_MASK]))
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data = data.replace(bytes([HDLC.FLAG]), bytes([HDLC.ESC, HDLC.FLAG^HDLC.ESC_MASK]))
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return data
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# Let's define our custom interface class. It must
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# be a sub-class of the RNS "Interface" class.
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class ExampleInterface(Interface):
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# All interface classes must define a default
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# IFAC size, used in IFAC setup when the user
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# has not specified a custom IFAC size. This
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# option is specified in bytes.
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DEFAULT_IFAC_SIZE = 8
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# The following properties are local to this
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# particular interface implementation.
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owner = None
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port = None
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speed = None
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databits = None
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parity = None
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stopbits = None
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serial = None
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# All Reticulum interfaces must have an __init__
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# method that takes 2 positional arguments:
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# The owner RNS Transport instance, and a dict
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# of configuration values.
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def __init__(self, owner, configuration):
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# The following lines demonstrate handling
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# potential dependencies required for the
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# interface to function correctly.
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import importlib
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if importlib.util.find_spec('serial') != None:
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import serial
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else:
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RNS.log("Using this interface requires a serial communication module to be installed.", RNS.LOG_CRITICAL)
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RNS.log("You can install one with the command: python3 -m pip install pyserial", RNS.LOG_CRITICAL)
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RNS.panic()
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# We start out by initialising the super-class
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super().__init__()
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# To make sure the configuration data is in the
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# correct format, we parse it through the following
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# method on the generic Interface class. This step
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# is required to ensure compatibility on all the
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# platforms that Reticulum supports.
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ifconf = Interface.get_config_obj(configuration)
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# Read the interface name from the configuration
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# and set it on our interface instance.
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name = ifconf["name"]
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self.name = name
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# We read configuration parameters from the supplied
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# configuration data, and provide default values in
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# case any are missing.
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port = ifconf["port"] if "port" in ifconf else None
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speed = int(ifconf["speed"]) if "speed" in ifconf else 9600
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databits = int(ifconf["databits"]) if "databits" in ifconf else 8
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parity = ifconf["parity"] if "parity" in ifconf else "N"
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stopbits = int(ifconf["stopbits"]) if "stopbits" in ifconf else 1
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# In case no port is specified, we abort setup by
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# raising an exception.
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if port == None:
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raise ValueError(f"No port specified for {self}")
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# All interfaces must supply a hardware MTU value
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# to the RNS Transport instance. This value should
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# be the maximum data packet payload size that the
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# underlying medium is capable of handling in all
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# cases without any segmentation.
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self.HW_MTU = 564
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# We initially set the "online" property to false,
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# since the interface has not actually been fully
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# initialised and connected yet.
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self.online = False
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# In this case, we can also set the indicated bit-
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# rate of the interface to the serial port speed.
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self.bitrate = self.speed
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# Configure internal properties on the interface
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# according to the supplied configuration.
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self.pyserial = serial
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self.serial = None
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self.owner = owner
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self.port = port
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self.speed = speed
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self.databits = databits
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self.parity = serial.PARITY_NONE
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self.stopbits = stopbits
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self.timeout = 100
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if parity.lower() == "e" or parity.lower() == "even":
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self.parity = serial.PARITY_EVEN
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if parity.lower() == "o" or parity.lower() == "odd":
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self.parity = serial.PARITY_ODD
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# Since all required parameters are now configured,
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# we will try opening the serial port.
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try:
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self.open_port()
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except Exception as e:
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RNS.log("Could not open serial port for interface "+str(self), RNS.LOG_ERROR)
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raise e
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# If opening the port succeeded, run any post-open
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# configuration required.
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if self.serial.is_open:
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self.configure_device()
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else:
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raise IOError("Could not open serial port")
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# Open the serial port with supplied configuration
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# parameters and store a reference to the open port.
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def open_port(self):
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RNS.log("Opening serial port "+self.port+"...", RNS.LOG_VERBOSE)
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self.serial = self.pyserial.Serial(
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port = self.port,
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baudrate = self.speed,
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bytesize = self.databits,
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parity = self.parity,
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stopbits = self.stopbits,
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xonxoff = False,
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rtscts = False,
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timeout = 0,
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inter_byte_timeout = None,
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write_timeout = None,
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dsrdtr = False,
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)
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# The only thing required after opening the port
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# is to wait a small amount of time for the
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# hardware to initialise and then start a thread
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# that reads any incoming data from the device.
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def configure_device(self):
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sleep(0.5)
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thread = threading.Thread(target=self.read_loop)
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thread.daemon = True
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thread.start()
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self.online = True
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RNS.log("Serial port "+self.port+" is now open", RNS.LOG_VERBOSE)
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# This method will be called from our read-loop
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# whenever a full packet has been received over
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# the underlying medium.
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def process_incoming(self, data):
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# Update our received bytes counter
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self.rxb += len(data)
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# And send the data packet to the Transport
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# instance for processing.
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self.owner.inbound(data, self)
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# The running Reticulum Transport instance will
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# call this method on the interface whenever the
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# interface must transmit a packet.
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def process_outgoing(self,data):
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if self.online:
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# First, escape and packetize the data
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# according to HDLC framing.
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data = bytes([HDLC.FLAG])+HDLC.escape(data)+bytes([HDLC.FLAG])
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# Then write the framed data to the port
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written = self.serial.write(data)
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# Update the transmitted bytes counter
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# and ensure that all data was written
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self.txb += len(data)
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if written != len(data):
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raise IOError("Serial interface only wrote "+str(written)+" bytes of "+str(len(data)))
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# This read loop runs in a thread and continously
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# receives bytes from the underlying serial port.
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# When a full packet has been received, it will
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# be sent to the process_incoming methed, which
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# will in turn pass it to the Transport instance.
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def read_loop(self):
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try:
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in_frame = False
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escape = False
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data_buffer = b""
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last_read_ms = int(time.time()*1000)
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while self.serial.is_open:
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if self.serial.in_waiting:
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byte = ord(self.serial.read(1))
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last_read_ms = int(time.time()*1000)
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if (in_frame and byte == HDLC.FLAG):
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in_frame = False
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self.process_incoming(data_buffer)
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elif (byte == HDLC.FLAG):
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in_frame = True
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data_buffer = b""
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elif (in_frame and len(data_buffer) < self.HW_MTU):
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if (byte == HDLC.ESC):
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escape = True
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else:
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if (escape):
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if (byte == HDLC.FLAG ^ HDLC.ESC_MASK):
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byte = HDLC.FLAG
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if (byte == HDLC.ESC ^ HDLC.ESC_MASK):
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byte = HDLC.ESC
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escape = False
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data_buffer = data_buffer+bytes([byte])
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else:
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time_since_last = int(time.time()*1000) - last_read_ms
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if len(data_buffer) > 0 and time_since_last > self.timeout:
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data_buffer = b""
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in_frame = False
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escape = False
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sleep(0.08)
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except Exception as e:
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self.online = False
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RNS.log("A serial port error occurred, the contained exception was: "+str(e), RNS.LOG_ERROR)
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RNS.log("The interface "+str(self)+" experienced an unrecoverable error and is now offline.", RNS.LOG_ERROR)
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if RNS.Reticulum.panic_on_interface_error:
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RNS.panic()
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RNS.log("Reticulum will attempt to reconnect the interface periodically.", RNS.LOG_ERROR)
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self.online = False
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self.serial.close()
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self.reconnect_port()
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# This method handles serial port disconnects.
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def reconnect_port(self):
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while not self.online:
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try:
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time.sleep(5)
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RNS.log("Attempting to reconnect serial port "+str(self.port)+" for "+str(self)+"...", RNS.LOG_VERBOSE)
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self.open_port()
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if self.serial.is_open:
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self.configure_device()
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except Exception as e:
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RNS.log("Error while reconnecting port, the contained exception was: "+str(e), RNS.LOG_ERROR)
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RNS.log("Reconnected serial port for "+str(self))
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# Signal to Reticulum that this interface should
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# not perform any ingress limiting.
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def should_ingress_limit(self):
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return False
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# We must provide a string representation of this
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# interface, that is used whenever the interface
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# is printed in logs or external programs.
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def __str__(self):
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return "ExampleInterface["+self.name+"]"
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# Finally, register the defined interface class as the
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# target class for Reticulum to use as an interface
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interface_class = ExampleInterface
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