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// Copyright 2016 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 (
"fmt"
"math"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/rlp"
set "gopkg.in/fatih/set.v0"
)
// peer represents a whisper protocol peer connection.
type Peer struct {
host *Whisper
peer *p2p.Peer
ws p2p.MsgReadWriter
trusted bool
powRequirement float64
known *set.Set // Messages already known by the peer to avoid wasting bandwidth
quit chan struct{}
}
// newPeer creates a new whisper peer object, but does not run the handshake itself.
func newPeer(host *Whisper, remote *p2p.Peer, rw p2p.MsgReadWriter) *Peer {
return &Peer{
host: host,
peer: remote,
ws: rw,
trusted: false,
powRequirement: 0.0,
known: set.New(),
quit: make(chan struct{}),
}
}
// start initiates the peer updater, periodically broadcasting the whisper packets
// into the network.
func (p *Peer) start() {
go p.update()
log.Trace("start", "peer", p.ID())
}
// stop terminates the peer updater, stopping message forwarding to it.
func (p *Peer) stop() {
close(p.quit)
log.Trace("stop", "peer", p.ID())
}
// handshake sends the protocol initiation status message to the remote peer and
// verifies the remote status too.
func (p *Peer) handshake() error {
// Send the handshake status message asynchronously
errc := make(chan error, 1)
go func() {
errc <- p2p.Send(p.ws, statusCode, ProtocolVersion)
}()
// Fetch the remote status packet and verify protocol match
packet, err := p.ws.ReadMsg()
if err != nil {
return err
}
if packet.Code != statusCode {
return fmt.Errorf("peer [%x] sent packet %x before status packet", p.ID(), packet.Code)
}
s := rlp.NewStream(packet.Payload, uint64(packet.Size))
peerVersion, err := s.Uint()
if err != nil {
return fmt.Errorf("peer [%x] sent bad status message: %v", p.ID(), err)
}
if peerVersion != ProtocolVersion {
return fmt.Errorf("peer [%x]: protocol version mismatch %d != %d", p.ID(), peerVersion, ProtocolVersion)
}
// Wait until out own status is consumed too
if err := <-errc; err != nil {
return fmt.Errorf("peer [%x] failed to send status packet: %v", p.ID(), err)
}
return nil
}
// update executes periodic operations on the peer, including message transmission
// and expiration.
func (p *Peer) update() {
// Start the tickers for the updates
expire := time.NewTicker(expirationCycle)
transmit := time.NewTicker(transmissionCycle)
// Loop and transmit until termination is requested
for {
select {
case <-expire.C:
p.expire()
case <-transmit.C:
if err := p.broadcast(); err != nil {
log.Trace("broadcast failed", "reason", err, "peer", p.ID())
return
}
case <-p.quit:
return
}
}
}
// mark marks an envelope known to the peer so that it won't be sent back.
func (peer *Peer) mark(envelope *Envelope) {
peer.known.Add(envelope.Hash())
}
// marked checks if an envelope is already known to the remote peer.
func (peer *Peer) marked(envelope *Envelope) bool {
return peer.known.Has(envelope.Hash())
}
// expire iterates over all the known envelopes in the host and removes all
// expired (unknown) ones from the known list.
func (peer *Peer) expire() {
unmark := make(map[common.Hash]struct{})
peer.known.Each(func(v interface{}) bool {
if !peer.host.isEnvelopeCached(v.(common.Hash)) {
unmark[v.(common.Hash)] = struct{}{}
}
return true
})
// Dump all known but no longer cached
for hash := range unmark {
peer.known.Remove(hash)
}
}
// broadcast iterates over the collection of envelopes and transmits yet unknown
// ones over the network.
func (p *Peer) broadcast() error {
envelopes := p.host.Envelopes()
bundle := make([]*Envelope, 0, len(envelopes))
for _, envelope := range envelopes {
if !p.marked(envelope) && envelope.PoW() >= p.powRequirement {
bundle = append(bundle, envelope)
}
}
if len(bundle) > 0 {
// transmit the batch of envelopes
if err := p2p.Send(p.ws, messagesCode, bundle); err != nil {
return err
}
// mark envelopes only if they were successfully sent
for _, e := range bundle {
p.mark(e)
}
log.Trace("broadcast", "num. messages", len(bundle))
}
return nil
}
func (p *Peer) ID() []byte {
id := p.peer.ID()
return id[:]
}
func (p *Peer) notifyAboutPowRequirementChange(pow float64) error {
i := math.Float64bits(pow)
return p2p.Send(p.ws, powRequirementCode, i)
}
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