Documentation
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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 ¶
Examples ¶
Constants ¶
const NodeIDBits = 512
const Version = 4
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Config ¶
type Config struct {
// These settings are required and configure the UDP listener:
PrivateKey *ecdsa.PrivateKey
// These settings are optional:
AnnounceAddr *net.UDPAddr // local address announced in the DHT
NodeDBPath string // if set, the node database is stored at this filesystem location
NetRestrict *netutil.Netlist // network whitelist
Bootnodes []*Node // list of bootstrap nodes
Unhandled chan<- ReadPacket // unhandled packets are sent on this channel
}
Config holds Table-related settings.
type Node ¶
type Node struct {
IP net.IP // len 4 for IPv4 or 16 for IPv6
UDP, TCP uint16 // port numbers
ID NodeID // the node's public key
// contains filtered or unexported fields
}
Node represents a host on the network. The fields of Node may not be modified.
func MustParseNode ¶
MustParseNode parses a node URL. It panics if the URL is not valid.
func NewNode ¶
NewNode creates a new node. It is mostly meant to be used for testing purposes.
Example ¶
id := MustHexID("1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439")
// Complete nodes contain UDP and TCP endpoints:
n1 := NewNode(id, net.ParseIP("2001:db8:3c4d:15::abcd:ef12"), 52150, 30303)
fmt.Println("n1:", n1)
fmt.Println("n1.Incomplete() ->", n1.Incomplete())
// An incomplete node can be created by passing zero values
// for all parameters except id.
n2 := NewNode(id, nil, 0, 0)
fmt.Println("n2:", n2)
fmt.Println("n2.Incomplete() ->", n2.Incomplete())
Output: n1: enode://1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439@[2001:db8:3c4d:15::abcd:ef12]:30303?discport=52150 n1.Incomplete() -> false n2: enode://1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439 n2.Incomplete() -> true
func ParseNode ¶
ParseNode parses a node designator.
There are two basic forms of node designators
- incomplete nodes, which only have the public key (node ID)
- complete nodes, which contain the public key and IP/Port information
For incomplete nodes, the designator must look like one of these
enode://<hex node id> <hex node id>
For complete nodes, the 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) Incomplete ¶
Incomplete returns true for nodes with no IP address.
func (*Node) MarshalText ¶
MarshalText implements encoding.TextMarshaler.
func (*Node) String ¶
The string representation of a Node is a URL. Please see ParseNode for a description of the format.
func (*Node) UnmarshalText ¶
UnmarshalText implements encoding.TextUnmarshaler.
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 MustBytesID ¶
MustBytesID converts a byte slice to a NodeID. It panics if the byte slice is not a valid NodeID.
func MustHexID ¶
MustHexID converts a hex string to a NodeID. It panics if the string is not a valid NodeID.
func (NodeID) MarshalText ¶
MarshalText implements the encoding.TextMarshaler interface.
func (NodeID) Pubkey ¶
Pubkey returns the public key represented by the node ID. It returns an error if the ID is not a point on the curve.
func (NodeID) TerminalString ¶
TerminalString returns a shortened hex string for terminal logging.
func (*NodeID) UnmarshalText ¶
UnmarshalText implements the encoding.TextUnmarshaler interface.
type ReadPacket ¶
ReadPacket is sent to the unhandled channel when it could not be processed
type Table ¶
type Table struct {
// contains filtered or unexported fields
}
func (*Table) Add ¶
Add attempts to add the given node its corresponding bucket. If the bucket has space available, adding the node succeeds immediately. Otherwise, the node is added if the least recently active node in the bucket does not respond to a ping packet.
func (*Table) Close ¶
func (tab *Table) Close()
Close terminates the network listener and flushes the node database.
func (*Table) Lookup ¶
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. The given target does not need to be an actual node identifier.
func (*Table) ReadRandomNodes ¶
ReadRandomNodes fills the given slice with random nodes from the table. It will not write the same node more than once. The nodes in the slice are copies and can be modified by the caller.
Source Files