mdnsforwarder

README

MDNSForwarder

This is an app which allows to forward MDNS messages between different networks. The primary intend is to forward MDNS queries through unicast addresses (like a VPN network).

It has been succesfully tested to run on an OpenWRT router using the mips processor connecting to a docker container network in Kubernetes.

Usage

mdnsforwarder --log-level DEBUG --config config.json

If no config path is specified the default (/etc/config/mdnsforwarder) is used.

Refer to the config.json for an example. The configuration options are:

• mdnsInterfaces: list of interfaces which should route mdnstraffic between each other
• listeners: Host/Port combination where unicast messages including mdns messages via UDP is expected
• targets: The list of targets where MDNS traffic from the local interfaces should be forwarded to.
• skip_own_ip: Defaults to true. If set to false, this will handle all messages which are also send by the own list and should only be used in special environments.

Availability

• The program is pulished as a self running go-executable for various platforms in the releases tab.
• To run it in a docker container, the image is published in Docker Hub with the image cbrand/mdnsforwarder.

Caveats

The remote MDNS traffic forwarding doesn't have any security. It doesn't encrypt any traffic and relies on protection from a lower layer (for example by utilizing a VPN). DO NOT USE THIS DIRECTLY OVER THE OPEN INTERNET.

License

The application is published via the MIT license.

Documentation

Index

• type Forwarder
  • func New(interfaces []*net.Interface, listenerIps []*net.UDPAddr, ...) Forwarder
• type ForwarderImpl
  • func (forwarder *ForwarderImpl) GetTargets() []*net.UDPAddr
  • func (forwarder *ForwarderImpl) ListenerIps() []*net.UDPAddr
  • func (forwarder *ForwarderImpl) MDNSNetworkInterfaces() []*net.Interface
  • func (forwarder *ForwarderImpl) Run() error
  • func (forwarder *ForwarderImpl) SkipOwnIP() bool
• type Handler
  • func NewHandler(forwarder Forwarder) *Handler
  • func (handler *Handler) Run() error
  • func (handler *Handler) Start() error
• type InterfaceCache
  • func (interfaceCache *InterfaceCache) IsInNetwork(networkInterface *net.Interface, address net.IP) bool
• type InterfaceHandler
  • func NewInterfaceHandler(networkInterface *net.Interface) (*InterfaceHandler, error)
  • func NewInterfaceHandlerWithAddress(networkInterface *net.Interface, multicastAddress string) (*InterfaceHandler, error)
  • func (interfaceHandler *InterfaceHandler) Run(channel chan *UDPMessage) error
  • func (interfaceHandler *InterfaceHandler) Send(message []byte) error
  • func (interfaceHandler *InterfaceHandler) Start() error
  • func (interfaceHandler *InterfaceHandler) Stop() error
• type ListenerHandler
  • func NewListenerHandler(addr *net.UDPAddr) (*ListenerHandler, error)
  • func (handler *ListenerHandler) Close() error
  • func (handler *ListenerHandler) Run(channel chan *RemoteUDPMessage) error
  • func (handler *ListenerHandler) Start() error
• type RemoteUDPMessage
• type TargetHandler
  • func NewTargetHandler(target *net.UDPAddr) *TargetHandler
  • func (handler *TargetHandler) Send(data []byte) error
• type TimedInterfaceCache
  • func NewTimedInterfaceCache() *TimedInterfaceCache
  • func NewTimedInterfaceCacheExpiresAt(expires time.Time) *TimedInterfaceCache
  • func (interfaceCache *TimedInterfaceCache) Expired() bool
  • func (interfaceCache *TimedInterfaceCache) IsInNetwork(networkInterface *net.Interface, address net.IP) bool
• type UDPMessage

Types

type Forwarder

type Forwarder interface {
	MDNSNetworkInterfaces() []*net.Interface
	ListenerIps() []*net.UDPAddr
	GetTargets() []*net.UDPAddr
	SkipOwnIP() bool
	Run() error
}

Forwarder is the main interface which is used to store information for the mdns forwarder to handle network multicasting.

func New

func New(interfaces []*net.Interface, listenerIps []*net.UDPAddr, targets []*net.UDPAddr, skipOwnIP bool) Forwarder

type ForwarderImpl

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

func (*ForwarderImpl) GetTargets

func (forwarder *ForwarderImpl) GetTargets() []*net.UDPAddr

func (*ForwarderImpl) ListenerIps

func (forwarder *ForwarderImpl) ListenerIps() []*net.UDPAddr

func (*ForwarderImpl) MDNSNetworkInterfaces

func (forwarder *ForwarderImpl) MDNSNetworkInterfaces() []*net.Interface

func (*ForwarderImpl) Run

func (forwarder *ForwarderImpl) Run() error

func (*ForwarderImpl) SkipOwnIP

func (forwarder *ForwarderImpl) SkipOwnIP() bool

type Handler

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

Handler includes the logic for forwarding and handling mdns messages.

func NewHandler

func NewHandler(forwarder Forwarder) *Handler

func (*Handler) Run

func (handler *Handler) Run() error

func (*Handler) Start

func (handler *Handler) Start() error

type InterfaceCache

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

func (*InterfaceCache) IsInNetwork

func (interfaceCache *InterfaceCache) IsInNetwork(networkInterface *net.Interface, address net.IP) bool

type InterfaceHandler

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

func NewInterfaceHandler

func NewInterfaceHandler(networkInterface *net.Interface) (*InterfaceHandler, error)

func NewInterfaceHandlerWithAddress

func NewInterfaceHandlerWithAddress(networkInterface *net.Interface, multicastAddress string) (*InterfaceHandler, error)

func (*InterfaceHandler) Run

func (interfaceHandler *InterfaceHandler) Run(channel chan *UDPMessage) error

func (*InterfaceHandler) Send

func (interfaceHandler *InterfaceHandler) Send(message []byte) error

func (*InterfaceHandler) Start

func (interfaceHandler *InterfaceHandler) Start() error

func (*InterfaceHandler) Stop

func (interfaceHandler *InterfaceHandler) Stop() error

type ListenerHandler

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

func NewListenerHandler

func NewListenerHandler(addr *net.UDPAddr) (*ListenerHandler, error)

func (*ListenerHandler) Close

func (handler *ListenerHandler) Close() error

func (*ListenerHandler) Run

func (handler *ListenerHandler) Run(channel chan *RemoteUDPMessage) error

func (*ListenerHandler) Start

func (handler *ListenerHandler) Start() error

type RemoteUDPMessage

type RemoteUDPMessage struct {
	Address  *net.UDPAddr
	NumBytes int
	Data     []byte
}

RemoteUDPMessage represents a data being sent to a unicast listener for forwarding the message to all local networks.

type TargetHandler

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

func NewTargetHandler

func NewTargetHandler(target *net.UDPAddr) *TargetHandler

func (*TargetHandler) Send

func (handler *TargetHandler) Send(data []byte) error

type TimedInterfaceCache

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

func NewTimedInterfaceCache

func NewTimedInterfaceCache() *TimedInterfaceCache

func NewTimedInterfaceCacheExpiresAt

func NewTimedInterfaceCacheExpiresAt(expires time.Time) *TimedInterfaceCache

func (*TimedInterfaceCache) Expired

func (interfaceCache *TimedInterfaceCache) Expired() bool

func (*TimedInterfaceCache) IsInNetwork

func (interfaceCache *TimedInterfaceCache) IsInNetwork(networkInterface *net.Interface, address net.IP) bool

type UDPMessage

type UDPMessage struct {
	Interface *net.Interface
	Address   *net.UDPAddr
	NumBytes  int
	Data      []byte
}

UDPMessage is a message structure which represents one sent datagram from a listened message.