netforward

README

Network forwarding

Forward network packets between various protocols, e.g. TCP <-> UDP, TLS <-> TCP.

Install

go get github.com/goburrow/netforward/nf

Usage

nf [OPTIONS]

OPTIONS:
  -address string
        listen address (default "localhost:7000")
  -caFile string
        client certificate authorities file
  -certFile string
        certificate file
  -keyFile string
        certificate key file
  -network string
        network protocol (default "tcp")
  -remote.address string
        remote address (default "localhost:8000")
  -remote.caFile string
        server certificate authorities file
  -remote.certFile string
        certificate file
  -remote.keyFile string
        certificate key file
  -remote.network string
        network protocol (default "tcp")
  -remote.skipVerify
        Not to verify remote server certificate

With default options, nf will divert TCP packets from localhost:7000 to localhost:8000

Use cases

Protect an unsecure HTTP server

• Many budget Internet of Things such as camera or sensor can only be accessed via a plain HTTP server.
• By using port forwarding, they can be viewed from Internet but it is a risk to expose password when login.
• VPN or SSL tunnel is too much overhead.

To mitigate, run a TLS endpoint in front of the unsecure HTTP server:

openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout /path/to/cert.key -out /path/to/cert.crt

nf -certFile /path/to/cert.crt -keyFile /path/to/cert.key -address :8443 -remote.address 127.0.0.1:8080

Then only forward port 8443 in your router.

Certificates can also be acquired from https://letsencrypt.org or self-signed https://github.com/OpenVPN/easy-rsa

Documentation

Index

• func Forward(remote Dialer, local net.Listener) error
• func ForwardPacket(remote Dialer, local net.PacketConn) error
• type Dialer
• type Endpoint
  • func (e *Endpoint) Dial() (net.Conn, error)
  • func (e *Endpoint) Listen() (net.Listener, error)
  • func (e *Endpoint) ListenPacket() (net.PacketConn, error)
• type Forwarder
• type NetForwarder
  • func (f *NetForwarder) Close() error
  • func (f *NetForwarder) Forward(remote Dialer) error
  • func (f *NetForwarder) Listen() error

Functions

func Forward

func Forward(remote Dialer, local net.Listener) error

func ForwardPacket

func ForwardPacket(remote Dialer, local net.PacketConn) error

Types

type Dialer

type Dialer interface {
	Dial() (net.Conn, error)
}

Dialer dials to a remote address.

type Endpoint

type Endpoint struct {
	Network string
	Address string

	TLS *tls.Config

	// Remote
	Timeout time.Duration
}

Endpoint is a network endpoint which can dial to or listen from.

func (*Endpoint) Dial

func (e *Endpoint) Dial() (net.Conn, error)

Dial dials to the given network endpoint.

func (*Endpoint) Listen

func (e *Endpoint) Listen() (net.Listener, error)

Listen returns a listener of a local address. Network must be a stream type.

func (*Endpoint) ListenPacket

func (e *Endpoint) ListenPacket() (net.PacketConn, error)

ListenPacket returns a listener of a local address. Network must be a packet oriented type.

type Forwarder

type Forwarder interface {
	Forward(remote Dialer) error
}

Forwarder forwards packets sending to the local network to the remote network.

type NetForwarder

type NetForwarder struct {
	Local Endpoint
	// contains filtered or unexported fields
}

func (*NetForwarder) Close

func (f *NetForwarder) Close() error

func (*NetForwarder) Forward

func (f *NetForwarder) Forward(remote Dialer) error

func (*NetForwarder) Listen

func (f *NetForwarder) Listen() error