discover

Documentation

Overview

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.

Index

• type Node
  • func MustParseNode(rawurl string) *Node
  • func ParseNode(rawurl string) (*Node, error)
  • func (n *Node) DecodeRLP(s *rlp.Stream) (err error)
  • func (n Node) EncodeRLP(w io.Writer) error
  • func (n *Node) String() string
• type NodeID
  • func HexID(in string) (NodeID, error)
  • func MustHexID(in string) NodeID
  • func PubkeyID(pub *ecdsa.PublicKey) NodeID
  • func (n NodeID) GoString() string
  • func (n NodeID) String() string
• type Table
  • func ListenUDP(priv *ecdsa.PrivateKey, laddr string, natm nat.Interface) (*Table, error)
  • func (tab *Table) Bootstrap(nodes []*Node)
  • func (tab *Table) Close()
  • func (tab *Table) Lookup(target NodeID) []*Node
  • func (tab *Table) Self() NodeID

Types

type Node

type Node struct {
	ID NodeID
	IP net.IP

	DiscPort int // UDP listening port for discovery protocol
	TCPPort  int // TCP listening port for RLPx
	// contains filtered or unexported fields
}

Node represents a host on the network.

func MustParseNode

func MustParseNode(rawurl string) *Node

MustParseNode parses a node URL. It panics if the URL is not valid.

func ParseNode

func ParseNode(rawurl string) (*Node, error)

ParseNode parses a node URL.

A node URL has scheme "enode".

The hexadecimal node ID is encoded in the username portion of the URL, separated from the host by an @ sign. The hostname can only be given as an IP address, DNS domain names are not allowed. The port in the host name section is the TCP listening port. If the TCP and UDP (discovery) ports differ, the UDP port is specified as query parameter "discport".

In the following example, the node URL describes a node with IP address 10.3.58.6, TCP listening port 30303 and UDP discovery port 30301.

enode://<hex node id>@10.3.58.6:30303?discport=30301

func (*Node) DecodeRLP

func (n *Node) DecodeRLP(s *rlp.Stream) (err error)

func (Node) EncodeRLP

func (n Node) EncodeRLP(w io.Writer) error

func (*Node) String

func (n *Node) String() string

The string representation of a Node is a URL. Please see ParseNode for a description of the format.

type NodeID

type NodeID [nodeIDBits / 8]byte

NodeID is a unique identifier for each node. The node identifier is a marshaled elliptic curve public key.

func HexID

func HexID(in string) (NodeID, error)

HexID converts a hex string to a NodeID. The string may be prefixed with 0x.

func MustHexID

func MustHexID(in string) NodeID

MustHexID converts a hex string to a NodeID. It panics if the string is not a valid NodeID.

func PubkeyID

func PubkeyID(pub *ecdsa.PublicKey) NodeID

PubkeyID returns a marshaled representation of the given public key.

func (NodeID) GoString

func (n NodeID) GoString() string

The Go syntax representation of a NodeID is a call to HexID.

func (NodeID) String

func (n NodeID) String() string

NodeID prints as a long hexadecimal number.

type Table

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

func ListenUDP

func ListenUDP(priv *ecdsa.PrivateKey, laddr string, natm nat.Interface) (*Table, error)

ListenUDP returns a new table that listens for UDP packets on laddr.

func (*Table) Bootstrap

func (tab *Table) Bootstrap(nodes []*Node)

Bootstrap sets the bootstrap nodes. These nodes are used to connect to the network if the table is empty. Bootstrap will also attempt to fill the table by performing random lookup operations on the network.

func (*Table) Close

func (tab *Table) Close()

Close terminates the network listener.

func (*Table) Lookup

func (tab *Table) Lookup(target NodeID) []*Node

Lookup performs a network search for nodes close to the given target. It approaches the target by querying nodes that are closer to it on each iteration.

func (*Table) Self

func (tab *Table) Self() NodeID

Self returns the local node ID.