natlab

Documentation

Overview

Package natlab lets us simulate different types of networks all in-memory without running VMs or requiring root, etc. Despite the name, it does more than just NATs. But NATs are the most interesting.

Index

• type Interface
  • func (f *Interface) Contains(ip netaddr.IP) bool
  • func (f *Interface) String() string
  • func (f *Interface) V4() netaddr.IP
  • func (f *Interface) V6() netaddr.IP
• type Machine
  • func (m *Machine) AddNetwork(n *Network)
  • func (m *Machine) Attach(interfaceName string, n *Network) *Interface
  • func (m *Machine) Inject(p []byte, dst, src netaddr.IPPort) error
  • func (m *Machine) ListenPacket(network, address string) (net.PacketConn, error)
• type Network
  • func NewInternet() *Network
  • func (n *Network) SetDefaultGateway(gw *Machine)
• type PacketHandler
• type PacketVerdict
  • func (v PacketVerdict) String() string

Types

type Interface

type Interface struct {
	// contains filtered or unexported fields
}

func (*Interface) Contains

func (f *Interface) Contains(ip netaddr.IP) bool

Contains reports whether f contains ip as an IP.

func (*Interface) String

func (f *Interface) String() string

func (*Interface) V4

func (f *Interface) V4() netaddr.IP

V4 returns the machine's first IPv4 address, or the zero value if none.

func (*Interface) V6

func (f *Interface) V6() netaddr.IP

V6 returns the machine's first IPv6 address, or the zero value if none.

type Machine

type Machine struct {
	// Name is a pretty name for debugging and packet tracing. It need
	// not be globally unique.
	Name string

	// HandlePacket, if not nil, is a function that gets invoked for
	// every packet this Machine receives. Returns a verdict for how
	// the packet should continue to be handled (or not).
	//
	// This can be used to implement things like stateful firewalls
	// and NAT boxes.
	HandlePacket PacketHandler
	// contains filtered or unexported fields
}

A Machine is a representation of an operating system's network stack. It has a network routing table and can have multiple attached networks. The zero value is valid, but lacks any networking capability until Attach is called.

func (*Machine) AddNetwork

func (m *Machine) AddNetwork(n *Network)

func (*Machine) Attach

func (m *Machine) Attach(interfaceName string, n *Network) *Interface

Attach adds an interface to a machine.

The first interface added to a Machine becomes that machine's default route.

func (*Machine) Inject

func (m *Machine) Inject(p []byte, dst, src netaddr.IPPort) error

Inject transmits p from src to dst, without the need for a local socket. It's useful for implementing e.g. NAT boxes that need to mangle IPs.

func (*Machine) ListenPacket

func (m *Machine) ListenPacket(network, address string) (net.PacketConn, error)

type Network

type Network struct {
	Name    string
	Prefix4 netaddr.IPPrefix
	Prefix6 netaddr.IPPrefix
	// contains filtered or unexported fields
}

func NewInternet

func NewInternet() *Network

NewInternet returns a network that simulates the internet.

func (*Network) SetDefaultGateway

func (n *Network) SetDefaultGateway(gw *Machine)

type PacketHandler

type PacketHandler func(p []byte, dst, src netaddr.IPPort) PacketVerdict

A PacketHandler is a function that can process packets.

type PacketVerdict

type PacketVerdict int

A PacketVerdict is a decision of what to do with a packet.

const (
	// Continue means the packet should be processed by the "local
	// sockets" logic of the Machine.
	Continue PacketVerdict = iota
	// Drop means the packet should not be handled further.
	Drop
)

func (PacketVerdict) String

func (v PacketVerdict) String() string