dummynet.DummyNet

class dummynet.DummyNet(shell, namespace=<factory>, cgroups=<factory>, namespaces=<factory>, cleaners=<factory>)

A DummyNet object is used to create a network of virtual ethernet devices and bind them to namespaces.

Parameters:
__init__(shell, namespace=<factory>, cgroups=<factory>, namespaces=<factory>, cleaners=<factory>)
Parameters:
Return type:

None

add_cgroup(name, shell, log, cpu_limit=None, memory_limit=None)

Creates a new cgroup object.

Parameters:

  • name (str) – The name of the cgroup.

  • shell (NamespaceShell | HostShell) – The shell object used for executing shell commands.

  • log (Logger) – The log object used for logging messages.

  • cpu_limit (float | None) – The ratio of CPU usage limit for the cgroup. Between 0 and 1. Defaults to None.

  • memory_limit (int | None) – The memory usage hard-limit for the cgroup. In bytes. Defaults to None. if memory usage exceeds the limit, the processes will get killed by the kernel. OOM.

Returns:

A CGroup object.

Return type:

CGroup

addr_add(ip, interface)

Adds an IP-address to a network interface.

Parameters:
Return type:

None

addr_del(ip, interface)

Deletes an IP-address to a network interface.

Parameters:
Return type:

None

bridge_add(name)

Adds a bridge

Parameters:

name (str)

Return type:

InterfaceScoped

bridge_list()

List the different bridges

Return type:

list[InterfaceScoped]

bridge_set(bridge, interface)

Adds an interface to a bridge

Parameters:
Return type:

None

cgroup_list()

Returns a list of all cgroups. Runs ‘find /sys/fs/cgroup -maxdepth 1 -mindepth 1 -type d’

Return type:

list[CGroupScoped]

cleanup()

Cleans up all the created network namespaces and bridges

Return type:

None

down(interface)

Sets the given network device to ‘down’

Parameters:

interface (InterfaceScoped | str)

Return type:

None

forward(from_interface, to_interface)

Forwards all traffic from one network interface to another.

Parameters:
Return type:

None

Deletes a specific network interface.

Parameters:

interface (InterfaceScoped | str)

Return type:

None

Returns the output of the ‘ip link list’ command parsed to a list of strings

Parameters:

link_type – The type of link to list (e.g. veth or bridge)

Returns:

A list of interfaces of the links

Return type:

list[InterfaceScoped]

Binds a network interface (usually the veths) to a namespace.

The namespace parameter is the name of the namespace as a string

Parameters:

  • namespace (NamespaceScoped | Self | str) – The namespace to bind the interface to

  • interface (InterfaceScoped | str) – The interface to bind to the namespace

Return type:

None

Adds a virtual ethernet between two endpoints.

Name of the link will be ‘p1_name@p2_name’ when you look at ‘ip addr’ in the terminal

Parameters:

  • p1_name (str) – Name of the first endpoint

  • p2_name (str) – Name of the second endpoint

Returns:

A 2-tuple of p1_name and p2_name as interfaces

Return type:

tuple[InterfaceScoped, InterfaceScoped]

Add a VLAN subinterface to a parent interface.

Parameters:

  • parent_interface (InterfaceScoped | str) – The parent interface to create a vlan from

  • vlan_id (int) – The numeric identifier of the vlan to add the interface to

Return type:

InterfaceScoped

netns_add(name)

Adds a new network namespace.

Returns a new DummyNet object with a NamespaceShell, a wrapper to the command-line but with every command prefixed by ‘ip netns exec name’ This returned object is the main component for creating a dummy-network. Configuring these namespaces with the other utility commands allows you to configure the networks.

Parameters:

name (str)

Return type:

Self

netns_delete(namespace)

Deletes a specific network namespace. Note that before deleting a network namespace all processes in that namespace should be killed. Using e.g.:

process_list = net.netns_get_process_list(ns_name).splitlines()
for process in process_list:
    self.netns_kill_process(name, process)
Parameters:

  • name – The namespace to delete

  • namespace (NamespaceScoped | Self | str)

netns_kill_all(namespace)

Kills all processes running in a network namespace

Parameters:

namespace (NamespaceScoped | Self | str)

netns_kill_process(namespace, pid)

Kills a process in a network namespace

Parameters:
netns_list()

Returns a list of all network namespaces. Runs ‘ip netns list’

Return type:

list[NamespaceScoped]

netns_process_list(namespace)

Returns a list of all processes in a network namespace

Parameters:

namespace (NamespaceScoped | Self | str)

Return type:

list[str]

route(ip)

Sets a new default IP-route.

Parameters:

ip (str)

Return type:

None

run(cmd, cwd=None)

Wrapper for the command-line access

Parameters:

  • cmd (str) – The command to run

  • cwd – The working directory to run the command in

Return type:

RunInfo

run_async(cmd, daemon=False, cwd=None)

Wrapper for the concurrent command-line access

Asynchronous commands run in the background. The process is launched via the shell.

Parameters:

  • cmd (str) – The command to run

  • daemon – Whether to run the command as a daemon

  • cwd – The working directory to run the command in

Return type:

RunInfo

tc(interface, delay=None, loss=None, rate=None, limit=None, cwd=None)

Modifies the given interface by adding any artificial combination of delay, packet loss, bandwidth constraints or queue limits

Parameters:

interface (InterfaceScoped | str)

Return type:

None

tc_show(interface, cwd=None)

Shows the current traffic-control configurations in the given interface

Parameters:

interface (InterfaceScoped | str)

up(interface)

Sets the given network device to ‘up’

Parameters:

interface (InterfaceScoped | str)

Return type:

None