147 lines
3.5 KiB
Go
147 lines
3.5 KiB
Go
package router
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import (
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"net"
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)
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// Interface to overlay network packet handling
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type Overlay interface {
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// Start consuming forwarded packets.
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StartConsumingPackets(*Peer, *Peers, OverlayConsumer) error
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// Form a packet-forwarding connection.
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MakeForwarder(ForwarderParams) (OverlayForwarder, error)
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// The routes have changed, so any cached information should
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// be discarded.
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InvalidateRoutes()
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// A mapping of a short id to a peer has changed
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InvalidateShortIDs()
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// Enhance a features map with overlay-related features
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AddFeaturesTo(map[string]string)
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// Obtain diagnostic information specific to the overlay
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Diagnostics() interface{}
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}
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type ForwarderParams struct {
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RemotePeer *Peer
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// The local IP address to use for sending. Derived from the
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// local address of the corresponding TCP socket, so may
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// differ for different forwarders.
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LocalIP net.IP
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// The remote address to send to. nil if unknown, i.e. an
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// incoming connection, in which case the Overlay needs to
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// discover it (e.g. from incoming datagrams).
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RemoteAddr *net.UDPAddr
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// Unique identifier for this connection
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ConnUID uint64
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// Crypto bits. Nil if not encrypting
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Crypto *OverlayCrypto
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// Function to send a control message to the counterpart
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// forwarder.
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SendControlMessage func(tag byte, msg []byte) error
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// Features passed at connection initiation
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Features map[string]string
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}
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// When a consumer is called, the decoder will already have been used
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// to decode the frame.
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type OverlayConsumer func(ForwardPacketKey) FlowOp
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// Crypto settings for a forwarder.
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type OverlayCrypto struct {
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Dec Decryptor
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Enc Encryptor
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EncDF Encryptor
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}
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// All of the machinery to forward packets to a particular peer
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type OverlayForwarder interface {
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// Forward a packet across the connection. May be called as
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// soon as the forwarder is created, in particular before
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// Confirm(). The return value nil means the key could not be
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// handled by this forwarder.
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Forward(ForwardPacketKey) FlowOp
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// Confirm that the connection is really wanted, and so the
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// Overlay should begin heartbeats etc. to verify the
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// operation of the forwarder.
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Confirm()
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// A channel indicating that the forwarder is established,
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// i.e. its operation has been confirmed.
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EstablishedChannel() <-chan struct{}
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// A channel indicating an error from the forwarder. The
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// forwarder is not expected to be operational after the first
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// error, so the channel only needs to buffer a single error.
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ErrorChannel() <-chan error
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Stop()
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// Handle a message from the peer. 'tag' exists for
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// compatibility, and should always be
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// ProtocolOverlayControlMessage for non-sleeve overlays.
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ControlMessage(tag byte, msg []byte)
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// User facing overlay name
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DisplayName() string
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}
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type NullOverlay struct{}
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func (NullOverlay) StartConsumingPackets(*Peer, *Peers, OverlayConsumer) error {
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return nil
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}
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func (NullOverlay) MakeForwarder(ForwarderParams) (OverlayForwarder, error) {
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return NullOverlay{}, nil
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}
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func (NullOverlay) InvalidateRoutes() {
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}
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func (NullOverlay) InvalidateShortIDs() {
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}
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func (NullOverlay) Confirm() {
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}
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func (NullOverlay) EstablishedChannel() <-chan struct{} {
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return nil
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}
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func (NullOverlay) ErrorChannel() <-chan error {
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return nil
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}
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func (NullOverlay) AddFeaturesTo(map[string]string) {
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}
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func (NullOverlay) Forward(ForwardPacketKey) FlowOp {
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return DiscardingFlowOp{}
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}
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func (NullOverlay) Stop() {
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}
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func (NullOverlay) ControlMessage(byte, []byte) {
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}
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func (NullOverlay) DisplayName() string {
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return "null"
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}
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func (NullOverlay) Diagnostics() interface{} {
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return nil
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}
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