github.com/gnolang/gno@v0.0.0-20240520182011-228e9d0192ce/tm2/pkg/p2p/peer.go

package p2p

import (
	"fmt"
	"log/slog"
	"net"

	"github.com/gnolang/gno/tm2/pkg/cmap"
	connm "github.com/gnolang/gno/tm2/pkg/p2p/conn"
	"github.com/gnolang/gno/tm2/pkg/service"
)

// Peer is an interface representing a peer connected on a reactor.
type Peer interface {
	service.Service
	FlushStop()

	ID() ID               // peer's cryptographic ID
	RemoteIP() net.IP     // remote IP of the connection
	RemoteAddr() net.Addr // remote address of the connection

	IsOutbound() bool   // did we dial the peer
	IsPersistent() bool // do we redial this peer when we disconnect

	CloseConn() error // close original connection

	NodeInfo() NodeInfo // peer's info
	Status() connm.ConnectionStatus
	SocketAddr() *NetAddress // actual address of the socket

	Send(byte, []byte) bool
	TrySend(byte, []byte) bool

	Set(string, interface{})
	Get(string) interface{}
}

// ----------------------------------------------------------

// peerConn contains the raw connection and its config.
type peerConn struct {
	outbound   bool
	persistent bool
	conn       net.Conn // source connection

	socketAddr *NetAddress

	// cached RemoteIP()
	ip net.IP
}

func newPeerConn(
	outbound, persistent bool,
	conn net.Conn,
	socketAddr *NetAddress,
) peerConn {
	return peerConn{
		outbound:   outbound,
		persistent: persistent,
		conn:       conn,
		socketAddr: socketAddr,
	}
}

// ID only exists for SecretConnection.
// NOTE: Will panic if conn is not *SecretConnection.
func (pc peerConn) ID() ID {
	return (pc.conn.(*connm.SecretConnection).RemotePubKey()).Address().ID()
}

// Return the IP from the connection RemoteAddr
func (pc peerConn) RemoteIP() net.IP {
	if pc.ip != nil {
		return pc.ip
	}

	host, _, err := net.SplitHostPort(pc.conn.RemoteAddr().String())
	if err != nil {
		panic(err)
	}

	ips, err := net.LookupIP(host)
	if err != nil {
		panic(err)
	}

	pc.ip = ips[0]

	return pc.ip
}

// peer implements Peer.
//
// Before using a peer, you will need to perform a handshake on connection.
type peer struct {
	service.BaseService

	// raw peerConn and the multiplex connection
	peerConn
	mconn *connm.MConnection

	// peer's node info and the channel it knows about
	// channels = nodeInfo.Channels
	// cached to avoid copying nodeInfo in hasChannel
	nodeInfo NodeInfo
	channels []byte

	// User data
	Data *cmap.CMap
}

type PeerOption func(*peer)

func newPeer(
	pc peerConn,
	mConfig connm.MConnConfig,
	nodeInfo NodeInfo,
	reactorsByCh map[byte]Reactor,
	chDescs []*connm.ChannelDescriptor,
	onPeerError func(Peer, interface{}),
	options ...PeerOption,
) *peer {
	p := &peer{
		peerConn: pc,
		nodeInfo: nodeInfo,
		channels: nodeInfo.Channels, // TODO
		Data:     cmap.NewCMap(),
	}

	p.mconn = createMConnection(
		pc.conn,
		p,
		reactorsByCh,
		chDescs,
		onPeerError,
		mConfig,
	)
	p.BaseService = *service.NewBaseService(nil, "Peer", p)
	for _, option := range options {
		option(p)
	}

	return p
}

// String representation.
func (p *peer) String() string {
	if p.outbound {
		return fmt.Sprintf("Peer{%v %v out}", p.mconn, p.ID())
	}

	return fmt.Sprintf("Peer{%v %v in}", p.mconn, p.ID())
}

// ---------------------------------------------------
// Implements service.Service

// SetLogger implements BaseService.
func (p *peer) SetLogger(l *slog.Logger) {
	p.Logger = l
	p.mconn.SetLogger(l)
}

// OnStart implements BaseService.
func (p *peer) OnStart() error {
	if err := p.BaseService.OnStart(); err != nil {
		return err
	}

	if err := p.mconn.Start(); err != nil {
		return err
	}

	return nil
}

// FlushStop mimics OnStop but additionally ensures that all successful
// .Send() calls will get flushed before closing the connection.
// NOTE: it is not safe to call this method more than once.
func (p *peer) FlushStop() {
	p.BaseService.OnStop()
	p.mconn.FlushStop() // stop everything and close the conn
}

// OnStop implements BaseService.
func (p *peer) OnStop() {
	p.BaseService.OnStop()
	p.mconn.Stop() // stop everything and close the conn
}

// ---------------------------------------------------
// Implements Peer

// ID returns the peer's ID - the hex encoded hash of its pubkey.
func (p *peer) ID() ID {
	return p.nodeInfo.NetAddress.ID
}

// IsOutbound returns true if the connection is outbound, false otherwise.
func (p *peer) IsOutbound() bool {
	return p.peerConn.outbound
}

// IsPersistent returns true if the peer is persistent, false otherwise.
func (p *peer) IsPersistent() bool {
	return p.peerConn.persistent
}

// NodeInfo returns a copy of the peer's NodeInfo.
func (p *peer) NodeInfo() NodeInfo {
	return p.nodeInfo
}

// SocketAddr returns the address of the socket.
// For outbound peers, it's the address dialed (after DNS resolution).
// For inbound peers, it's the address returned by the underlying connection
// (not what's reported in the peer's NodeInfo).
func (p *peer) SocketAddr() *NetAddress {
	return p.peerConn.socketAddr
}

// Status returns the peer's ConnectionStatus.
func (p *peer) Status() connm.ConnectionStatus {
	return p.mconn.Status()
}

// Send msg bytes to the channel identified by chID byte. Returns false if the
// send queue is full after timeout, specified by MConnection.
func (p *peer) Send(chID byte, msgBytes []byte) bool {
	if !p.IsRunning() {
		// see Switch#Broadcast, where we fetch the list of peers and loop over
		// them - while we're looping, one peer may be removed and stopped.
		return false
	} else if !p.hasChannel(chID) {
		return false
	}
	res := p.mconn.Send(chID, msgBytes)
	return res
}

// TrySend msg bytes to the channel identified by chID byte. Immediately returns
// false if the send queue is full.
func (p *peer) TrySend(chID byte, msgBytes []byte) bool {
	if !p.IsRunning() {
		return false
	} else if !p.hasChannel(chID) {
		return false
	}
	res := p.mconn.TrySend(chID, msgBytes)
	return res
}

// Get the data for a given key.
func (p *peer) Get(key string) interface{} {
	return p.Data.Get(key)
}

// Set sets the data for the given key.
func (p *peer) Set(key string, data interface{}) {
	p.Data.Set(key, data)
}

// hasChannel returns true if the peer reported
// knowing about the given chID.
func (p *peer) hasChannel(chID byte) bool {
	for _, ch := range p.channels {
		if ch == chID {
			return true
		}
	}
	// NOTE: probably will want to remove this
	// but could be helpful while the feature is new
	p.Logger.Debug(
		"Unknown channel for peer",
		"channel",
		chID,
		"channels",
		p.channels,
	)
	return false
}

// CloseConn closes original connection. Used for cleaning up in cases where the peer had not been started at all.
func (p *peer) CloseConn() error {
	return p.peerConn.conn.Close()
}

// ---------------------------------------------------
// methods only used for testing
// TODO: can we remove these?

// CloseConn closes the underlying connection
func (pc *peerConn) CloseConn() {
	pc.conn.Close() //nolint: errcheck
}

// RemoteAddr returns peer's remote network address.
func (p *peer) RemoteAddr() net.Addr {
	return p.peerConn.conn.RemoteAddr()
}

// CanSend returns true if the send queue is not full, false otherwise.
func (p *peer) CanSend(chID byte) bool {
	if !p.IsRunning() {
		return false
	}
	return p.mconn.CanSend(chID)
}

// ------------------------------------------------------------------
// helper funcs

func createMConnection(
	conn net.Conn,
	p *peer,
	reactorsByCh map[byte]Reactor,
	chDescs []*connm.ChannelDescriptor,
	onPeerError func(Peer, interface{}),
	config connm.MConnConfig,
) *connm.MConnection {
	onReceive := func(chID byte, msgBytes []byte) {
		reactor := reactorsByCh[chID]
		if reactor == nil {
			// Note that its ok to panic here as it's caught in the connm._recover,
			// which does onPeerError.
			panic(fmt.Sprintf("Unknown channel %X", chID))
		}
		reactor.Receive(chID, p, msgBytes)
	}

	onError := func(r interface{}) {
		onPeerError(p, r)
	}

	return connm.NewMConnectionWithConfig(
		conn,
		chDescs,
		onReceive,
		onError,
		config,
	)
}