Python implementation to send a fake SSDP discovery message to Bambu Studio or Orca Slicer

bambu-ssdp-discovery.py

# Derived from this: https://github.com/gashton/bambustudio_tools/blob/master/bambudiscovery.sh
# Python implementation without need for linux
# Send the IP address of your BambuLab printer to port 2021/udp, which BambuStudio is listens on.

# Ensure your PC has firewall pot 2021/udp open. This is required as the proper response would usually go to the ephemeral source port that the M-SEARCH ssdp:discover message.
# But we are are blindly sending a response directly to the BambuStudio listening service port (2021/udp).

# Temporary solution to BambuStudio not allowing you to manually specify the Printer IP.

# Usage:
# 0. Edit the constants below with your printer SN, model name and the friendly name you want to see in Studio / Orca Slicer
# 1. start Bambu Studio / Orca Slicer
# 2. python bambu-ssdp-discovery.py PRINTER_IP
# 3. connect to the printer

# The script needs to be run every time you start Studio or Orca Slicer

import sys
import socket
from datetime import datetime

TARGET_IP = "127.0.0.1" # Change this to the IP of the computer with the printer software. If you're running this on the same computer, leave it as is.
PRINTER_USN = "YOUR_PRINTER_SN" # This is the serial number of the printer. https://wiki.bambulab.com/en/general/find-sn
PRINTER_DEV_MODEL = "3DPrinter-X1-Carbon" # "3DPrinter-X1-Carbon", "3DPrinter-X1", "C11" (for P1P), "C12" (for P1S), "C13" (for X1E), "N1" (A1 mini), "N2S" (A1)
PRINTER_DEV_NAME = "X1C-1" # The friendly name displayed in Bambu Studio / Orca Slicer. Set this to whatever you want.
PRINTER_DEV_SIGNAL = "-44" # Fake wifi signal strength
PRINTER_DEV_CONNECT = "lan" # printer is in lan only mode
PRINTER_DEV_BIND = "free" # and is not bound to any cloud account
PRINTER_IP = None # If you want to hardcode the printer IP, set it here. Otherwise, pass it as the first argument to the script.
TARGET_PORT = 2021 # The port used for SSDP discovery

def send_udp_response(response):
    with socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as sock:
        try:
            sock.sendto(response.encode(), (TARGET_IP, TARGET_PORT))
            print("UDP packet sent successfully.")
        except socket.error as e:
            print("Error sending UDP packet:", e)

def resolve_and_validate(input_str):
    """Resolve a hostname or FQDN to an IP address, or just return the IP address after validating it."""
    try:
        # This will work for both FQDN and hostname
        return socket.gethostbyname(input_str)
    except socket.gaierror:
        # If resolution fails, check if it's a valid IP
        try:
            socket.inet_aton(input_str)
            return input_str  # It's a valid IP, so return it as-is
        except socket.error:
            print(f"Unable to resolve {input_str} to an IP address.")
            sys.exit(2)

def main():
    if PRINTER_IP is None:
        # If PRINTER_IP is not set, check if it was passed as an argument
        if len(sys.argv) == 2:
            provided_ip = sys.argv[1]
        else:
            print("Please specify your printer's IP, FQDN or hostname.\nusage:", sys.argv[0], "<PRINTER_IP>\nAlternatively, set PRINTER_IP in the script.")
            sys.exit(2)
    else:
        # If PRINTER_IP is set, use that
        provided_ip = PRINTER_IP

    # Now that we have a printer IP, FQDN or hostname, resolve and validate it
    printer_ip = resolve_and_validate(provided_ip)

    response = (
        f"HTTP/1.1 200 OK\r\n"
        f"Server: Buildroot/2018.02-rc3 UPnP/1.0 ssdpd/1.8\r\n"
        f"Date: {datetime.now()}\r\n"
        f"Location: {printer_ip}\r\n"
        f"ST: urn:bambulab-com:device:3dprinter:1\r\n"
        f"EXT:\r\n"
        f"USN: {PRINTER_USN}\r\n"
        f"Cache-Control: max-age=1800\r\n"
        f"DevModel.bambu.com: {PRINTER_DEV_MODEL}\r\n"
        f"DevName.bambu.com: {PRINTER_DEV_NAME}\r\n"
        f"DevSignal.bambu.com: {PRINTER_DEV_SIGNAL}\r\n"
        f"DevConnect.bambu.com: {PRINTER_DEV_CONNECT}\r\n"
        f"DevBind.bambu.com: {PRINTER_DEV_BIND}\r\n\r\n"
    )
    print(f"Sending response with PRINTER_IP={printer_ip} to {TARGET_IP}:{TARGET_PORT}")
    send_udp_response(response)

if __name__ == "__main__":
    main()

What does one do when it seems Bambu Studio isn't listening on 2021, or at least Windows sort of thinks so? Some tools tell me BS is listening on 2021, but then Windows Filtering Platform (WFP) drops packets sent to 2021, something it does when no one is listening on that part. These drops occur before the packed even gets to the firewall.

I think this is the reason 99% of LAN-only print jobs fail at either 30% or 70% progress. Turning off the firewall, which also silently turns off WFP, allows the print to succeed. But no amount of firewall rules help as WFP is dropping the packet before the firewall sees it.

Added a couple of lines to my copy to more closely match the detection specs for wireshark and SSDP. Turns out you also need a source port of 1900, or wireshark treats it as raw UDP.

def send_udp_response(response):
    with socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as sock:
        try:
            sock.bind(('', 1900))
            sock.sendto(response.encode(), (TARGET_IP, TARGET_PORT))
            print("UDP packet sent successfully.")
            sock.close()
        except socket.error as e:
            print("Error sending UDP packet:", e)

@skintigh The port 2021 should only be needed for the initial printer detection -- after that, other ports are needed to send data to the printer. Those are initiated by Bambu Studio, and replies should come in as related. Not sure whether Windows Firewall blocks any of those by default?

Windows firewall is blocking nothing when I have rules set up. It's WFP that seems to be eating packets. It appeared to be eating packets sent to 2021 but perhaps that was before a print started? I have yet to figure out the timestamps used, if any, in the WFP "logs."

All I know is a rule for 1990 and 2021 allows printer discovery. After that, calibration prints print instantly. The verify_job file transmits instantly. Then file to print transfers completely, THEN the printer hangs at 70% or 30%. No blocked packets in the firewall log, but if I turn off the firewall and thus WFP prints work.