Cisco-send scripts

Send a local config to Cisco device over serial/console connection.

Created as an alternative to the cumbersome tftp and xmodem etc methods of sending configs.
Copy pasting a config directly usually works for smaller configs however at a certain point configs are too large - data is sent too quickly and the device chokes, causing errors in the final config.

Herein lies the simplicity of automation by script - read a local config and send it to the device, with a configurable delay between lines to prevent errors.
This method does not require setting up an IP on the device for TFTP/SSH etc, or xmodem voodoo magic sending data over 9600 baud prior to configuring a device.

Rapid deployment; wipe and send.

This repository contains both an advanced multi-threaded asynchronous python - and a simple Shell version of the script.

Table of Contents

• Files
• Usage
  • Python Script
  • GNS3 Serial Bridge
  • Shell Script
• Features
  • Python Version
  • Shell Version

Files

 .
├──  Shell-Version
│  └──  cisco-send.sh
├──  send-GNS3
│  ├──  cisco-send-gns3.py
│  └──  gns3-serial-bridge.sh
├──  cisco-send.py
├──  LICENSE
├──  README.md
└──  requirements.txt

• cisco-send.py: Python script for sending config files to running-config.

• cisco-send-gns3.py: GNS3 version of the script, send configs into virtual devices.

• gns3-serial-bridge.sh: Used in conjunction with cisco-send-gns3.py. Maps telnet port to device file.

• requirements.txt: Lists Python packages required for the Python version.

• cisco-send.sh: Shell script for sending config files to running-config.

Usage

Python Script

usage: cisco-send.py [-h] [--device-file DEVICE_FILE] [--delay DELAY] input_file

Send a local config to a device over a serial/console connection.

positional arguments:
  input_file            Path to the config file for the Cisco device (Router/Switch).

options:
  -h, --help            show this help message and exit
  --device-file DEVICE_FILE
                        Path to device file. Default is --device-file /dev/ttyUSB0
  --delay DELAY         Delay between sending lines, in seconds. Default is --delay 0.2s

Confirm your device file, default is set to /dev/ttyUSB0

• DEFAULT_DEVICE_FILE and DEFAULT_DELAY variables can be set permanently inside script.
• --device-file and --delay are optional and override the defaults.

Install dependencies;

pip install -r requirements.txt || <your-pkg-manager> install pyserial

Run script;

python3 cisco-send.py <input_file>

Replace <input_file> with the path to the config file for the cisco device (Router/Switch)

You'll likely want to add the script to your $PATH ie. ~/.local/bin/

---

Shell Script

Run the Shell script using the following command:

chmod +x cisco-send.sh
./cisco-send.sh <input_file>

Replace <input_file> with the path to the config file.

---

GNS3 Serial Bridge

(for testing/virtual devices)

The gns3-serial-bridge.sh script works in conjunction with cisco-send-gns3.py to connect a Cisco device in GNS3 to a local device file, similar to a regular serial connection to /dev/ttyUSB0 etc. How to use:

• Start your Switch/Router device in GNS3. Right-click, select 'show node information'.
  Note the line Console is on port 5000 and type is telnet
• Run ./gns3-serial-bridge.sh as a regular user.
• You'll be prompted to provide a virtual device file name (default is ~/ttyCisco).
  (Note that if you change the default, you must also update the DEFAULT_DEVICE_FILE variable inside cisco-send-gns3.py)
• Provide the GNS3 device telnet port number when prompted (default is 5000).
• The script will then execute socat to map the provided telnet port to your virtual device file.
• Optionally, you'll be asked if you would like to launch screen with 8N1 configuration.

Now the GNS3 device can be treated as a regular serial device - connecting with other terminal programs, or executing the cisco-send-gns3.py script.

Features

Python Version

• Asynchronous Reading: Uses a separate thread to read from the serial port and print syslog messages.
• User Authentication: Detects & then handles password authentication if required.
• Automatic Elevation: Detects device state and elevates to (config)# mode automatically.
• Syslog Buffering: Stores all syslog messages in a buffer.
• User Prompts:
  • Asks if the user wants to print buffered syslog messages to the terminal.
  • Offers to save running-config to startup-config.
  • Provides an option to save syslog buffer to a local log file.
• Asks to write running-config to memory: Save the new config to startup-config
• Command line switches: to override default --device-file and --delay

Shell Version

• No External Dependencies: Doesn't require any additional libraries.
• No support if require credentials to enter Config# mode: Start with fresh device, wipe it, or manually enter # prompt prior to running script.
• No support for printing syslog messages: No syslog response returned to console due to shell single thread limitations.

---

TO-DO

• ask user to pull current config and write locally as backup
  (and/or create backup in flash: )
• support wiping device to clean state prior to sending config
• sanitize log file strings for cleaner output (\b, \r etc.)
• handle keyboard interrupts & exception handling when --device-file invalid