Meshtastic shell server for executing commands on a remote system attached to a meshtastic radio

mesh-shell-server.py

#!/usr/bin/env python3
#@atucom
# PoC of getting a remote shell using a meshtastic radio.
# this works by using the meshtastic python package and the device connected over USB serial
# The long/slow transmit speed gives about 10 bytes/sec bandwidth which is crazy slow. It took 5.5mins to run 'ls -la' on my home dir
# This could be further improved by the following:
# - trying the short/fast mode
# - creating a dedicated channel
# - setting a non-default psk for encryption
# - using sendData instead of sendText
# - creating a binary transfer protocol to protect against interference
# - simulating a tty
# - add a text compression algo to speed up convo (gzip?)
# again, this was all just a PoC to see if it was possible and at what speed it oprates at in long/slow.

import meshtastic
import meshtastic.serial_interface
from pubsub import pub
from subprocess import run, PIPE
import time

interface = meshtastic.serial_interface.SerialInterface()
chunk_size = 150

def onReceive(packet, interface): # called when a packet arrives
    # Only take action if the "portnum" of the meessage is a text message
    if packet['decoded']['portnum'] == 'TEXT_MESSAGE_APP': #meshtastic ios app for testing.
        from_id = packet['from']
        msg_payload = packet['decoded']['payload']
        msg_payload_utf8 = msg_payload.decode('utf8')
        print(f"Received: {msg_payload} from {from_id}")
        print(msg_payload.decode('utf8'))
        ret = run(str(msg_payload_utf8), stdout=PIPE, shell=True)
        output = ret.stdout
        chunks_to_send = [output[index : index + chunk_size] for index in range(0, len(output), chunk_size)]
        for chunk in chunks_to_send:
            chunk = chunk.decode('utf8')
            print(f"IM SENDING THIS NOW: {chunk}")
            interface.sendText(f"RESULT: {chunk}", destinationId=from_id)
            time.sleep(10)
        
while True:
    pub.subscribe(onReceive, "meshtastic.receive")