go-ethereum/whisper/whisperv6/libp2p_glue.go

// Copyright 2018 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package whisperv6

import (
	"bufio"
	"bytes"
	"context"
	"fmt"
	"github.com/ethereum/go-ethereum/log"
	"io"
	"time"

	"github.com/ethereum/go-ethereum/p2p"
	"github.com/ethereum/go-ethereum/rlp"
	crypto "github.com/libp2p/go-libp2p-crypto"
	host "github.com/libp2p/go-libp2p-host"
	inet "github.com/libp2p/go-libp2p-net"
	peer "github.com/libp2p/go-libp2p-peer"
	pstore "github.com/libp2p/go-libp2p-peerstore"
	swarm "github.com/libp2p/go-libp2p-swarm"
	"github.com/libp2p/go-libp2p/p2p/host/basic"
	ma "github.com/multiformats/go-multiaddr"
	set "gopkg.in/fatih/set.v0"
)

// LibP2PStream is a wrapper used to implement the MsgReadWriter
// interface for libp2p's streams.
type LibP2PStream struct {
	lp2pStream inet.Stream
	rlpStream  *rlp.Stream
}

func newLibp2pStream(lp2pStream inet.Stream) p2p.MsgReadWriter {
	return &LibP2PStream{lp2pStream: lp2pStream, rlpStream: rlp.NewStream(bufio.NewReader(lp2pStream), 0)}
}

// ReadMsg implements the MsgReadWriter interface to read messages
// from lilbp2p streams.
func (stream *LibP2PStream) ReadMsg() (p2p.Msg, error) {
	msgcode, err := stream.rlpStream.Uint()
	if err != nil {
		return p2p.Msg{}, fmt.Errorf("can't read message code: %v", err)
	}
	_, size, err := stream.rlpStream.Kind()
	if err != nil {
		return p2p.Msg{}, fmt.Errorf("can't read message size: %v", err)
	}
	// Only the size of the encoded payload is checked, so theoretically
	// the decrypted message could be much bigger. We would need to add
	// a function to rlp.Stream to find out what is the raw size. Since
	// this is still work in progress, we won't bother with that just yet.
	if size > uint64(MaxMessageSize) {
		return p2p.Msg{}, fmt.Errorf("message too large")
	}
	content, err := stream.rlpStream.Raw()
	if err != nil {
		return p2p.Msg{}, fmt.Errorf("can't read message: %v", err)
	}

	return p2p.Msg{Code: msgcode, Size: uint32(len(content)), Payload: bytes.NewReader(content)}, nil
}

// WriteMsg implements the MsgReadWriter interface to write messages
// to lilbp2p streams.
func (stream *LibP2PStream) WriteMsg(msg p2p.Msg) error {
	stream.lp2pStream.SetWriteDeadline(time.Now().Add(transmissionCycle))

	if err := rlp.Encode(stream.lp2pStream, msg.Code); err != nil {
		return err
	}
	_, err := io.Copy(stream.lp2pStream, msg.Payload)
		return err
	}

// LibP2PPeer implements Peer for libp2p
type LibP2PPeer struct {
	*PeerBase

	id peer.ID

	server *LibP2PWhisperServer

	connectionStream *LibP2PStream
}

func newLibP2PPeer(s *LibP2PWhisperServer, w *Whisper, pid peer.ID, rw p2p.MsgReadWriter) Peer {
	return &LibP2PPeer{
		&PeerBase{
			host:           w,
			ws:             rw,
			trusted:        false,
			powRequirement: 0.0,
			known:          set.New(),
			quit:           make(chan struct{}),
			bloomFilter:    makeFullNodeBloom(),
			fullNode:       true,
		},
		pid,
		s,
		nil,
	}
}

// ID returns the id of the peer
func (p *LibP2PPeer) ID() string {
	return p.id.String()
}

func (p *LibP2PPeer) handshake() error {
	err := p.handshakeBase()
	if err != nil {
		return fmt.Errorf("peer [%x] %s", p.ID(), err.Error())
	}
	return nil
}

// start initiates the peer updater, periodically broadcasting the whisper packets
// into the network.
func (p *LibP2PPeer) start() {
	go p.update()
	log.Trace("start", "peer", p.ID())
}

// stop terminates the peer updater, stopping message forwarding to it.
func (p *LibP2PPeer) stop() {
	close(p.quit)
	fmt.Println("stop", "peer", p.ID())
}

// update executes periodic operations on the peer, including message transmission
// and expiration.
func (p *LibP2PPeer) update() {
	// Start the tickers for the updates
	expire := time.NewTicker(expirationCycle)
	transmit := time.NewTicker(transmissionCycle)

	// Loop and transmit until termination is requested
updateLoop:
	for {
		select {
		case <-expire.C:
			p.expire()

		case <-transmit.C:
			if err := p.broadcast(); err != nil {
				break updateLoop
			}

		case <-p.quit:
			break updateLoop
		}
	}

	// Cleanup and remove the peer from the list
	for i, it := range p.server.Peers {
		if it.id == p.id {
			p.server.Peers = append(p.server.Peers[:i], p.server.Peers[i+1:]...)
			break
		}
	}
}

// LibP2PWhisperServer implements WhisperServer for libp2p.
type LibP2PWhisperServer struct {
	Host host.Host

	Peers []*LibP2PPeer

	whisper *Whisper
}

func (server *LibP2PWhisperServer) connectToPeer(p *LibP2PPeer) error {
	log.Info("opening stream to peer: ", p.id.Pretty(), "from peer", server.Host.ID().Pretty())

	// Create a stream with the peer
	s, err := server.Host.NewStream(context.Background(), p.id, WhisperProtocolString)
	if err != nil {
		return err
	}

	// Save the stream
	lps := newLibp2pStream(s).(*LibP2PStream)

	p.connectionStream = lps
	p.ws = p.connectionStream

	// TODO send my known list of peers
	
	// Call HandlePeer to perform the handshake
	go server.whisper.HandlePeer(p, p.connectionStream)
	
	return err
}

// Start starts the server
func (server *LibP2PWhisperServer) Start() error {
	server.Host.SetStreamHandler(WhisperProtocolString, func(stream inet.Stream) {
		log.Info("opening stream from new peer")
	
		pid := stream.Conn().RemotePeer()
		var peer Peer
		for _, p := range server.Peers {
			if p.id == pid {
				peer = p
				break
			}
		}

		lps := newLibp2pStream(stream).(*LibP2PStream)

		// Unknown peer
		if peer == nil {
			peer = newLibP2PPeer(server, server.whisper, pid, lps)
			// TODO check critical section
			server.Peers = append(server.Peers, peer.(*LibP2PPeer))
		}

		go server.whisper.HandlePeer(peer, lps)
	})

	fmt.Println("Currently having the following peers:", server.Peers)

	// Open a stream to every peer currently known
	var err error
	for _, p := range server.Peers {
		if e := server.connectToPeer(p); e != nil {
			err = e
		}
		}

	return err
}

// Stop stops the server
func (server *LibP2PWhisperServer) Stop() {
	for _, p := range server.Peers {
		// TODO send disconnect message
		p.connectionStream.lp2pStream.Close()
	}

	server.Host.Close()
}

// PeerCount returns the peer count for the node
func (server *LibP2PWhisperServer) PeerCount() int {
	return len(server.Peers)
}

// Enode returns the enode address of the node
func (server *LibP2PWhisperServer) Enode() string {
	addr := server.Host.Addrs()[0]
	hostAddr, _ := ma.NewMultiaddr(fmt.Sprintf("/ipfs/%s", server.Host.ID().Pretty()))
	fullAddr := addr.Encapsulate(hostAddr)
	return fullAddr.String()
}

// AddPeer is a helper function to add peers to the server
func (server *LibP2PWhisperServer) AddPeer(addr ma.Multiaddr) *LibP2PPeer {
	log.Info("Adding peer: ", addr)
	pid, err := addr.ValueForProtocol(ma.P_IPFS)
	if err != nil {
		// XXX
		panic(err)
	}
	peerid, err := peer.IDB58Decode(pid)
	if err != nil {
		panic(err)
	}
	ipfsaddrpart, _ := ma.NewMultiaddr(fmt.Sprintf("/ipfs/%s", pid))
	ipaddr := addr.Decapsulate(ipfsaddrpart)
	server.Host.Peerstore().AddAddr(peerid, ipaddr, pstore.PermanentAddrTTL)
	newPeer := newLibP2PPeer(server, server.whisper, peerid, nil).(*LibP2PPeer)
	server.Peers = append(server.Peers, newPeer)

	return newPeer
}

// NewLibP2PWhisperServer creates a new WhisperServer with
// a libp2p backend.
func NewLibP2PWhisperServer(port uint, whisper *Whisper) (WhisperServer, error) {
	priv, pub, err := crypto.GenerateKeyPair(crypto.Ed25519, 384)
	if err != nil {
		return nil, fmt.Errorf("Error creating libp2p server: %v", err)
	}
	nodeID, err := peer.IDFromPublicKey(pub)
	if err != nil {
		return nil, fmt.Errorf("Error creating libp2p server identity: %v pubkey=%v", err, pub)
	}
	serverAddr, err := ma.NewMultiaddr(fmt.Sprintf("/ip4/0.0.0.0/tcp/%d", port))
	if err != nil {
		return nil, fmt.Errorf("Error creating libp2p server address: %v port=%d", err, port)
	}

	ps := pstore.NewPeerstore()
	ps.AddPrivKey(nodeID, priv)
	ps.AddPubKey(nodeID, pub)

	network, err := swarm.NewNetwork(context.Background(), []ma.Multiaddr{serverAddr}, nodeID, ps, nil)
	if err != nil {
		return nil, fmt.Errorf("Error creating libp2p network: %v port=%d", err, port)
	}
	h := basichost.New(network)

	server := &LibP2PWhisperServer{h, []*LibP2PPeer{}, whisper}
	return server, nil
}