Fake-switches

Fake-switches is a pluggable switch/router command-line simulator. It is meant to help running integrated tests against network equipment without the burden of having devices in a lab. This helps testing the communication with the equipment along with all of its layers for more robust high level tests. Since it is meant to be used by other systems and not humans, error handling on incomplete commands and fail-proofing has been mostly left out and only relevant errors are shown.

The library can easily be extended to react to some changes in the fake switch configuration and control an actual set of tools to have an environment behaving like a real one driven by a switch. For example, you could hook yourself to the VLAN creation and use vconfig to create an actual vlan on a machine for some network testing.

This library is NOT supported by any vendor, it was built by reverse-engineering network equipment.

Actual supported commands

Command support has been added in a as-needed manner for the purpose of what was tested and how. So see which commands may be used and their supported behavior, please see the tests section for each model.

Model	Protocols	Test location
Cisco	ssh and telnet	tests/cisco/test_cisco_switch_protocol.py
Brocade	ssh	tests/brocade/test_brocade_switch_protocol.py
Juniper	netconf over ssh	tests/juniper/juniper_base_protocol_test.py
Dell	ssh and telnet	tests/dell/

Using it with Docker

$ docker run -P -d internap/fake-switches
$ docker ps
CONTAINER ID        IMAGE                             COMMAND                  CREATED             STATUS              PORTS                     NAMES
6eec86849561        internap/fake-switches            "/bin/sh -c 'fake-swi"   35 seconds ago      Up 13 seconds       0.0.0.0:32776->22/tcp     boring_thompson
$ ssh 127.0.0.1 -p 32776 -l root
root@127.0.0.1's password:  # root
my_switch>enable
Password:  # press <RETURN>
my_switch#show run
Building configuration...

Current configuration : 164 bytes
version 12.1
!
hostname my_switch
!
!
vlan 1
!
interface FastEthernet0/1
!
interface FastEthernet0/2
!
interface FastEthernet0/3
!
interface FastEthernet0/4
!
end

my_switch#

Launching with custom parameters

$ docker run -P -d -e SWITCH_MODEL="another_model" internap/fake-switches

Supported parameters

Name	Default value
SWITCH_MODEL	cisco_generic
SWITCH_HOSTNAME	switch
SWITCH_USERNAME	root
SWITCH_PASSWORD	root
LISTEN_HOST	0.0.0.0
LISTEN_PORT	22

Building image from source

$ docker build -t fake-switches .
$ docker run -P -d fake-switches

Extending functionality

The SwitchConfiguration class can be extended and given an object factory with custom classes that can act upon resources changes. For example :

from twisted.internet import reactor
from fake_switches.switch_configuration import SwitchConfiguration, Port
from fake_switches.transports.ssh_service import SwitchSshService
from fake_switches.cisco.cisco_core import CiscoSwitchCore

class MySwitchConfiguration(SwitchConfiguration):
    def __init__(self, *args, **kwargs):
        super(MySwitchConfiguration, self).__init__(objects_overrides={"Port": MyPort}, *args, **kwargs)


class MyPort(Port):
    def __init__(self, name):
        self._access_vlan = None

        super(MyPort, self).__init__(name)

    @property
    def access_vlan(self):
        return self._access_vlan

    @access_vlan.setter
    def access_vlan(self, value):
        if self._access_vlan != value:
            self._access_vlan = value
            print "This could add vlan to eth0"


if __name__ == '__main__':
    ssh_service = SwitchSshService(
        ip="127.0.0.1",
        ssh_port=11001,
        switch_core=CiscoSwitchCore(MySwitchConfiguration("127.0.0.1", "my_switch", ports=[MyPort("FastEthernet0/1")])))
    ssh_service.hook_to_reactor(reactor)
    reactor.run()

Then, if you connect to the switch and do

    ssh root@127.0.0.1 -p 11001
    password : root
    > enable
    password:
    # configure terminal
    # vlan 1000
    # interface FastEthernet0/1
    # switchport access vlan 1000

Your program should say "This could add vlan to eth0" or do anything you would want it to do :)

Starting a switch from the command line

    pip install fake-switches
    
    fake-switches

    # On a different shell, type the following:
    ssh root@127.0.0.1 -p 22222

Command line help

The --help flag is supported.

fake-switches --help
usage: fake-switches [-h] [--model MODEL] [--hostname HOSTNAME]
                     [--username USERNAME] [--password PASSWORD]
                     [--listen-host LISTEN_HOST] [--listen-port LISTEN_PORT]

Fake-switch simulator launcher

optional arguments:
  -h, --help            show this help message and exit
  --model MODEL         Switch model, allowed values are
                        juniper_qfx_copper_generic, cisco_2960_24TT_L,
                        dell_generic, dell10g_generic, juniper_generic,
                        cisco_2960_48TT_L, cisco_generic, brocade_generic
                        (default: cisco_generic)
  --hostname HOSTNAME   Switch hostname (default: switch)
  --username USERNAME   Switch username (default: root)
  --password PASSWORD   Switch password (default: root)
  --listen-host LISTEN_HOST
                        Listen host (default: 0.0.0.0)
  --listen-port LISTEN_PORT
                        Listen port (default: 2222)

Available switch models

At time of writing this document, the following models are available:

brocade_generic
cisco_generic
cisco_2960_24TT_L
cisco_2960_48TT_L
dell_generic
dell10g_generic
juniper_generic
juniper_qfx_copper_generic

Use the --help flag to find the available models.

The generic models are mainly for test purposes. They usually have less ports than a proper switch model but behave the same otherwise. Once a "core" is available, more specific models can be very easily added. Send your pull requests :)