Package p2p implements the Ethereum p2p network protocols.




This section is empty.


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var ErrPipeClosed = errors.New("p2p: read or write on closed message pipe")

ErrPipeClosed is returned from pipe operations after the pipe has been closed.

View Source
var (
	ErrShuttingDown = errors.New("shutting down")


func ExpectMsg

func ExpectMsg(r MsgReader, code uint64, content interface{}) error

ExpectMsg reads a message from r and verifies that its code and encoded RLP content match the provided values. If content is nil, the payload is discarded and not verified.

func MsgPipe

func MsgPipe() (*MsgPipeRW, *MsgPipeRW)

MsgPipe creates a message pipe. Reads on one end are matched with writes on the other. The pipe is full-duplex, both ends implement MsgReadWriter.



rw1, rw2 := MsgPipe()
go func() {
	Send(rw1, 8, [][]byte{{0, 0}})
	Send(rw1, 5, [][]byte{{1, 1}})

for {
	msg, err := rw2.ReadMsg()
	if err != nil {
	var data [][]byte
	fmt.Printf("msg: %d, %x\n", msg.Code, data[0])
msg: 8, 0000
msg: 5, 0101

func Send

func Send(w MsgWriter, msgcode uint64, data interface{}) error

Send writes an RLP-encoded message with the given code. data should encode as an RLP list.

func SendItems

func SendItems(w MsgWriter, msgcode uint64, elems ...interface{}) error

SendItems writes an RLP with the given code and data elements. For a call such as:

SendItems(w, code, e1, e2, e3)

the message payload will be an RLP list containing the items:

[e1, e2, e3]


type Cap

type Cap struct {
	Name    string
	Version uint

Cap is the structure of a peer capability.

func (Cap) String

func (cap Cap) String() string

type Config

type Config struct {
	// This field must be set to a valid secp256k1 private key.
	PrivateKey *ecdsa.PrivateKey `toml:"-"`

	// MaxPeers is the maximum number of peers that can be
	// connected. It must be greater than zero.
	MaxPeers int

	// MaxPendingPeers is the maximum number of peers that can be pending in the
	// handshake phase, counted separately for inbound and outbound connections.
	// Zero defaults to preset values.
	MaxPendingPeers int `toml:",omitempty"`

	// DialRatio controls the ratio of inbound to dialed connections.
	// Example: a DialRatio of 2 allows 1/2 of connections to be dialed.
	// Setting DialRatio to zero defaults it to 3.
	DialRatio int `toml:",omitempty"`

	// NoDiscovery can be used to disable the peer discovery mechanism.
	// Disabling is useful for protocol debugging (manual topology).
	NoDiscovery bool

	// DiscoveryV5 specifies whether the new topic-discovery based V5 discovery
	// protocol should be started or not.
	DiscoveryV5 bool `toml:",omitempty"`

	// Name sets the node name of this server.
	// Use common.MakeName to create a name that follows existing conventions.
	Name string `toml:"-"`

	// BootstrapNodes are used to establish connectivity
	// with the rest of the network.
	BootstrapNodes []*enode.Node

	// BootstrapNodesV5 are used to establish connectivity
	// with the rest of the network using the V5 discovery
	// protocol.
	BootstrapNodesV5 []*discv5.Node `toml:",omitempty"`

	// Static nodes are used as pre-configured connections which are always
	// maintained and re-connected on disconnects.
	StaticNodes []*enode.Node

	// Trusted nodes are used as pre-configured connections which are always
	// allowed to connect, even above the peer limit.
	TrustedNodes []*enode.Node

	// Connectivity can be restricted to certain IP networks.
	// If this option is set to a non-nil value, only hosts which match one of the
	// IP networks contained in the list are considered.
	NetRestrict *netutil.Netlist `toml:",omitempty"`

	// NodeDatabase is the path to the database containing the previously seen
	// live nodes in the network.
	NodeDatabase string `toml:",omitempty"`

	// Protocols should contain the protocols supported
	// by the server. Matching protocols are launched for
	// each peer.
	Protocols []Protocol `toml:"-"`

	// If ListenAddr is set to a non-nil address, the server
	// will listen for incoming connections.
	// If the port is zero, the operating system will pick a port. The
	// ListenAddr field will be updated with the actual address when
	// the server is started.
	ListenAddr string

	// If set to a non-nil value, the given NAT port mapper
	// is used to make the listening port available to the
	// Internet.
	NAT nat.Interface `toml:",omitempty"`

	// If Dialer is set to a non-nil value, the given Dialer
	// is used to dial outbound peer connections.
	Dialer NodeDialer `toml:"-"`

	// If NoDial is true, the server will not dial any peers.
	NoDial bool `toml:",omitempty"`

	// If EnableMsgEvents is set then the server will emit PeerEvents
	// whenever a message is sent to or received from a peer
	EnableMsgEvents bool

	// Logger is a custom logger to use with the p2p.Server.
	Logger log.Logger `toml:",omitempty"`

	// contains filtered or unexported fields


Config holds Server options.

type DiscReason

type DiscReason uint
const (
	DiscRequested DiscReason = iota
	DiscSubprotocolError = 0x10

func (DiscReason) Error

func (d DiscReason) Error() string

func (DiscReason) String

func (d DiscReason) String() string

type Msg

type Msg struct {
	Code       uint64
	Size       uint32 // Size of the raw payload
	Payload    io.Reader
	ReceivedAt time.Time

	// contains filtered or unexported fields


Msg defines the structure of a p2p message.

Note that a Msg can only be sent once since the Payload reader is consumed during sending. It is not possible to create a Msg and send it any number of times. If you want to reuse an encoded structure, encode the payload into a byte array and create a separate Msg with a bytes.Reader as Payload for each send.

func (Msg) Decode

func (msg Msg) Decode(val interface{}) error

Decode parses the RLP content of a message into the given value, which must be a pointer.

For the decoding rules, please see package rlp.

func (Msg) Discard

func (msg Msg) Discard() error

Discard reads any remaining payload data into a black hole.

func (Msg) String

func (msg Msg) String() string

type MsgPipeRW

type MsgPipeRW struct {

	// contains filtered or unexported fields


MsgPipeRW is an endpoint of a MsgReadWriter pipe.

func (*MsgPipeRW) Close

func (p *MsgPipeRW) Close() error

Close unblocks any pending ReadMsg and WriteMsg calls on both ends of the pipe. They will return ErrPipeClosed. Close also interrupts any reads from a message payload.

func (*MsgPipeRW) ReadMsg

func (p *MsgPipeRW) ReadMsg() (Msg, error)

ReadMsg returns a message sent on the other end of the pipe.

func (*MsgPipeRW) WriteMsg

func (p *MsgPipeRW) WriteMsg(msg Msg) error

WriteMsg sends a message on the pipe. It blocks until the receiver has consumed the message payload.

type MsgReadWriter

type MsgReadWriter interface {

MsgReadWriter provides reading and writing of encoded messages. Implementations should ensure that ReadMsg and WriteMsg can be called simultaneously from multiple goroutines.

type MsgReader

type MsgReader interface {
	ReadMsg() (Msg, error)

type MsgWriter

type MsgWriter interface {
	// WriteMsg sends a message. It will block until the message's
	// Payload has been consumed by the other end.
	// Note that messages can be sent only once because their
	// payload reader is drained.
	WriteMsg(Msg) error

type NodeDialer

type NodeDialer interface {
	Dial(context.Context, *enode.Node) (net.Conn, error)

NodeDialer is used to connect to nodes in the network, typically by using an underlying net.Dialer but also using net.Pipe in tests.

type NodeInfo

type NodeInfo struct {
	ID    string `json:"id"`    // Unique node identifier (also the encryption key)
	Name  string `json:"name"`  // Name of the node, including client type, version, OS, custom data
	Enode string `json:"enode"` // Enode URL for adding this peer from remote peers
	ENR   string `json:"enr"`   // Ethereum Node Record
	IP    string `json:"ip"`    // IP address of the node
	Ports struct {
		Discovery int `json:"discovery"` // UDP listening port for discovery protocol
		Listener  int `json:"listener"`  // TCP listening port for RLPx
	} `json:"ports"`
	ListenAddr string                 `json:"listenAddr"`
	Protocols  map[string]interface{} `json:"protocols"`

NodeInfo represents a short summary of the information known about the host.

type Peer

type Peer struct {

	// contains filtered or unexported fields


Peer represents a connected remote node.

func NewPeer

func NewPeer(id enode.ID, name string, caps []Cap) *Peer

NewPeer returns a peer for testing purposes.

func (*Peer) Caps

func (p *Peer) Caps() []Cap

Caps returns the capabilities (supported subprotocols) of the remote peer.

func (*Peer) Disconnect

func (p *Peer) Disconnect(reason DiscReason)

Disconnect terminates the peer connection with the given reason. It returns immediately and does not wait until the connection is closed.

func (*Peer) Fullname

func (p *Peer) Fullname() string

Fullname returns the node name that the remote node advertised.

func (*Peer) ID

func (p *Peer) ID() enode.ID

ID returns the node's public key.

func (*Peer) Inbound

func (p *Peer) Inbound() bool

Inbound returns true if the peer is an inbound connection

func (*Peer) Info

func (p *Peer) Info() *PeerInfo

Info gathers and returns a collection of metadata known about a peer.

func (*Peer) LocalAddr

func (p *Peer) LocalAddr() net.Addr

LocalAddr returns the local address of the network connection.

func (*Peer) Log

func (p *Peer) Log() log.Logger

func (*Peer) Name

func (p *Peer) Name() string

Name returns an abbreviated form of the name

func (*Peer) Node

func (p *Peer) Node() *enode.Node

Node returns the peer's node descriptor.

func (*Peer) RemoteAddr

func (p *Peer) RemoteAddr() net.Addr

RemoteAddr returns the remote address of the network connection.

func (*Peer) String

func (p *Peer) String() string

String implements fmt.Stringer.

type PeerEvent

type PeerEvent struct {
	Type          PeerEventType `json:"type"`
	Peer          enode.ID      `json:"peer"`
	Error         string        `json:"error,omitempty"`
	Protocol      string        `json:"protocol,omitempty"`
	MsgCode       *uint64       `json:"msg_code,omitempty"`
	MsgSize       *uint32       `json:"msg_size,omitempty"`
	LocalAddress  string        `json:"local,omitempty"`
	RemoteAddress string        `json:"remote,omitempty"`

PeerEvent is an event emitted when peers are either added or dropped from a p2p.Server or when a message is sent or received on a peer connection

type PeerEventType

type PeerEventType string

PeerEventType is the type of peer events emitted by a p2p.Server

const (
	// PeerEventTypeAdd is the type of event emitted when a peer is added
	// to a p2p.Server
	PeerEventTypeAdd PeerEventType = "add"

	// PeerEventTypeDrop is the type of event emitted when a peer is
	// dropped from a p2p.Server
	PeerEventTypeDrop PeerEventType = "drop"

	// PeerEventTypeMsgSend is the type of event emitted when a
	// message is successfully sent to a peer
	PeerEventTypeMsgSend PeerEventType = "msgsend"

	// PeerEventTypeMsgRecv is the type of event emitted when a
	// message is received from a peer
	PeerEventTypeMsgRecv PeerEventType = "msgrecv"

type PeerInfo

type PeerInfo struct {
	ENR     string   `json:"enr,omitempty"` // Ethereum Node Record
	Enode   string   `json:"enode"`         // Node URL
	ID      string   `json:"id"`            // Unique node identifier
	Name    string   `json:"name"`          // Name of the node, including client type, version, OS, custom data
	Caps    []string `json:"caps"`          // Protocols advertised by this peer
	Network struct {
		LocalAddress  string `json:"localAddress"`  // Local endpoint of the TCP data connection
		RemoteAddress string `json:"remoteAddress"` // Remote endpoint of the TCP data connection
		Inbound       bool   `json:"inbound"`
		Trusted       bool   `json:"trusted"`
		Static        bool   `json:"static"`
	} `json:"network"`
	Protocols map[string]interface{} `json:"protocols"` // Sub-protocol specific metadata fields

PeerInfo represents a short summary of the information known about a connected peer. Sub-protocol independent fields are contained and initialized here, with protocol specifics delegated to all connected sub-protocols.

type Protocol

type Protocol struct {
	// Name should contain the official protocol name,
	// often a three-letter word.
	Name string

	// Version should contain the version number of the protocol.
	Version uint

	// Length should contain the number of message codes used
	// by the protocol.
	Length uint64

	// Run is called in a new goroutine when the protocol has been
	// negotiated with a peer. It should read and write messages from
	// rw. The Payload for each message must be fully consumed.
	// The peer connection is closed when Start returns. It should return
	// any protocol-level error (such as an I/O error) that is
	// encountered.
	Run func(peer *Peer, rw MsgReadWriter) error

	// NodeInfo is an optional helper method to retrieve protocol specific metadata
	// about the host node.
	NodeInfo func() interface{}

	// PeerInfo is an optional helper method to retrieve protocol specific metadata
	// about a certain peer in the network. If an info retrieval function is set,
	// but returns nil, it is assumed that the protocol handshake is still running.
	PeerInfo func(id enode.ID) interface{}

	// DialCandidates, if non-nil, is a way to tell Server about protocol-specific nodes
	// that should be dialed. The server continuously reads nodes from the iterator and
	// attempts to create connections to them.
	DialCandidates enode.Iterator

	// Attributes contains protocol specific information for the node record.
	Attributes []enr.Entry

Protocol represents a P2P subprotocol implementation.

type Server

type Server struct {
	// Config fields may not be modified while the server is running.

	DiscV5 *discv5.Network

	// contains filtered or unexported fields


Server manages all peer connections.

func (*Server) AddPeer

func (srv *Server) AddPeer(node *enode.Node)

AddPeer adds the given node to the static node set. When there is room in the peer set, the server will connect to the node. If the connection fails for any reason, the server will attempt to reconnect the peer.

func (*Server) AddTrustedPeer

func (srv *Server) AddTrustedPeer(node *enode.Node)

AddTrustedPeer adds the given node to a reserved whitelist which allows the node to always connect, even if the slot are full.

func (*Server) LocalNode

func (srv *Server) LocalNode() *enode.LocalNode

LocalNode returns the local node record.

func (*Server) NodeInfo

func (srv *Server) NodeInfo() *NodeInfo

NodeInfo gathers and returns a collection of metadata known about the host.

func (*Server) PeerCount

func (srv *Server) PeerCount() int

PeerCount returns the number of connected peers.

func (*Server) Peers

func (srv *Server) Peers() []*Peer

Peers returns all connected peers.

func (*Server) PeersInfo

func (srv *Server) PeersInfo() []*PeerInfo

PeersInfo returns an array of metadata objects describing connected peers.

func (*Server) RemovePeer

func (srv *Server) RemovePeer(node *enode.Node)

RemovePeer removes a node from the static node set. It also disconnects from the given node if it is currently connected as a peer.

This method blocks until all protocols have exited and the peer is removed. Do not use RemovePeer in protocol implementations, call Disconnect on the Peer instead.

func (*Server) RemoveTrustedPeer

func (srv *Server) RemoveTrustedPeer(node *enode.Node)

RemoveTrustedPeer removes the given node from the trusted peer set.

func (*Server) Self

func (srv *Server) Self() *enode.Node

Self returns the local node's endpoint information.

func (*Server) SetupConn

func (srv *Server) SetupConn(fd net.Conn, flags connFlag, dialDest *enode.Node) error

SetupConn runs the handshakes and attempts to add the connection as a peer. It returns when the connection has been added as a peer or the handshakes have failed.

func (*Server) Start

func (srv *Server) Start() (err error)

Start starts running the server. Servers can not be re-used after stopping.

func (*Server) Stop

func (srv *Server) Stop()

Stop terminates the server and all active peer connections. It blocks until all active connections have been closed.

func (*Server) SubscribeEvents

func (srv *Server) SubscribeEvents(ch chan *PeerEvent) event.Subscription

SubscribePeers subscribes the given channel to peer events


Path Synopsis
discover Package discover implements the Node Discovery Protocol.
discover/v4wire Package v4wire implements the Discovery v4 Wire Protocol.
discv5 Package discv5 is a prototype implementation of Discvery v5.
dnsdisc Package dnsdisc implements node discovery via DNS (EIP-1459).
enr Package enr implements Ethereum Node Records as defined in EIP-778.
nat Package nat provides access to common network port mapping protocols.
netutil Package netutil contains extensions to the net package.
rlpx Package rlpx implements the RLPx transport protocol.
simulations Package simulations simulates p2p networks.