Version: v21.1.0+incompatible Latest Latest

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Published: Feb 1, 2021 License: GPL-3.0 Imports: 23 Imported by: 0



Package discover implements the Node Discovery Protocol.

The Node Discovery protocol provides a way to find RLPx nodes that can be connected to. It uses a Kademlia-like protocol to maintain a distributed database of the IDs and endpoints of all listening nodes.



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type Config

type Config struct {
	// These settings are required and configure the UDP listener:
	PrivateKey *ecdsa.PrivateKey

	// These settings are optional:
	NetRestrict *netutil.Netlist  // network whitelist
	Bootnodes   []*enode.Node     // list of bootstrap nodes
	Unhandled   chan<- ReadPacket // unhandled packets are sent on this channel
	Log         log.Logger        // if set, log messages go here

Config holds settings for the discovery listener.

type ReadPacket

type ReadPacket struct {
	Data []byte
	Addr *net.UDPAddr

ReadPacket is a packet that couldn't be handled. Those packets are sent to the unhandled channel if configured. This is exported for internal use, do not use this type.

type Table

type Table struct {
	// contains filtered or unexported fields

Table is the 'node table', a Kademlia-like index of neighbor nodes. The table keeps itself up-to-date by verifying the liveness of neighbors and requesting their node records when announcements of a new record version are received.

func (*Table) ReadRandomNodes added in v0.9.25

func (tab *Table) ReadRandomNodes(buf []*enode.Node) (n int)

ReadRandomNodes fills the given slice with random nodes from the table. The results are guaranteed to be unique for a single invocation, no node will appear twice.

type UDPConn

type UDPConn interface {
	ReadFromUDP(b []byte) (n int, addr *net.UDPAddr, err error)
	WriteToUDP(b []byte, addr *net.UDPAddr) (n int, err error)
	Close() error
	LocalAddr() net.Addr

UDPConn is a network connection on which discovery can operate.

type UDPv4

type UDPv4 struct {
	// contains filtered or unexported fields

UDPv4 implements the v4 wire protocol.

func ListenUDP

func ListenUDP(c UDPConn, ln *enode.LocalNode, cfg Config) (*UDPv4, error)

ListenUDP starts listening for discovery packets on the given UDP socket.

func ListenV4

func ListenV4(c UDPConn, ln *enode.LocalNode, cfg Config) (*UDPv4, error)

func (*UDPv4) Close

func (t *UDPv4) Close()

Close shuts down the socket and aborts any running queries.

func (*UDPv4) LookupPubkey

func (t *UDPv4) LookupPubkey(key *ecdsa.PublicKey) []*enode.Node

LookupPubkey finds the closest nodes to the given public key.

func (*UDPv4) Ping

func (t *UDPv4) Ping(n *enode.Node) error

Ping sends a ping message to the given node.

func (*UDPv4) RandomNodes

func (t *UDPv4) RandomNodes() enode.Iterator

RandomNodes is an iterator yielding nodes from a random walk of the DHT.

func (*UDPv4) RequestENR

func (t *UDPv4) RequestENR(n *enode.Node) (*enode.Node, error)

RequestENR sends enrRequest to the given node and waits for a response.

func (*UDPv4) Resolve

func (t *UDPv4) Resolve(n *enode.Node) *enode.Node

Resolve searches for a specific node with the given ID and tries to get the most recent version of the node record for it. It returns n if the node could not be resolved.

func (*UDPv4) Self

func (t *UDPv4) Self() *enode.Node

Self returns the local node.

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