plugeth/swarm/network/hive.go

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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 network
import (
"fmt"
"math/rand"
"path/filepath"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
"github.com/ethereum/go-ethereum/p2p/discover"
"github.com/ethereum/go-ethereum/swarm/network/kademlia"
"github.com/ethereum/go-ethereum/swarm/storage"
)
// Hive is the logistic manager of the swarm
// it uses a generic kademlia nodetable to find best peer list
// for any target
// this is used by the netstore to search for content in the swarm
// the bzz protocol peersMsgData exchange is relayed to Kademlia
// for db storage and filtering
// connections and disconnections are reported and relayed
// to keep the nodetable uptodate
type Hive struct {
listenAddr func() string
callInterval uint64
id discover.NodeID
addr kademlia.Address
kad *kademlia.Kademlia
path string
quit chan bool
toggle chan bool
more chan bool
// for testing only
swapEnabled bool
syncEnabled bool
blockRead bool
blockWrite bool
}
const (
callInterval = 3000000000
// bucketSize = 3
// maxProx = 8
// proxBinSize = 4
)
type HiveParams struct {
CallInterval uint64
KadDbPath string
*kademlia.KadParams
}
func NewHiveParams(path string) *HiveParams {
kad := kademlia.NewKadParams()
// kad.BucketSize = bucketSize
// kad.MaxProx = maxProx
// kad.ProxBinSize = proxBinSize
return &HiveParams{
CallInterval: callInterval,
KadDbPath: filepath.Join(path, "bzz-peers.json"),
KadParams: kad,
}
}
func NewHive(addr common.Hash, params *HiveParams, swapEnabled, syncEnabled bool) *Hive {
kad := kademlia.New(kademlia.Address(addr), params.KadParams)
return &Hive{
callInterval: params.CallInterval,
kad: kad,
addr: kad.Addr(),
path: params.KadDbPath,
swapEnabled: swapEnabled,
syncEnabled: syncEnabled,
}
}
func (self *Hive) SyncEnabled(on bool) {
self.syncEnabled = on
}
func (self *Hive) SwapEnabled(on bool) {
self.swapEnabled = on
}
func (self *Hive) BlockNetworkRead(on bool) {
self.blockRead = on
}
func (self *Hive) BlockNetworkWrite(on bool) {
self.blockWrite = on
}
// public accessor to the hive base address
func (self *Hive) Addr() kademlia.Address {
return self.addr
}
// Start receives network info only at startup
// listedAddr is a function to retrieve listening address to advertise to peers
// connectPeer is a function to connect to a peer based on its NodeID or enode URL
// there are called on the p2p.Server which runs on the node
func (self *Hive) Start(id discover.NodeID, listenAddr func() string, connectPeer func(string) error) (err error) {
self.toggle = make(chan bool)
self.more = make(chan bool)
self.quit = make(chan bool)
self.id = id
self.listenAddr = listenAddr
err = self.kad.Load(self.path, nil)
if err != nil {
glog.V(logger.Warn).Infof("Warning: error reading kaddb '%s' (skipping): %v", self.path, err)
err = nil
}
// this loop is doing bootstrapping and maintains a healthy table
go self.keepAlive()
go func() {
// whenever toggled ask kademlia about most preferred peer
for alive := range self.more {
if !alive {
// receiving false closes the loop while allowing parallel routines
// to attempt to write to more (remove Peer when shutting down)
return
}
node, need, proxLimit := self.kad.Suggest()
if node != nil && len(node.Url) > 0 {
glog.V(logger.Detail).Infof("call known bee %v", node.Url)
// enode or any lower level connection address is unnecessary in future
// discovery table is used to look it up.
connectPeer(node.Url)
}
if need {
// a random peer is taken from the table
peers := self.kad.FindClosest(kademlia.RandomAddressAt(self.addr, rand.Intn(self.kad.MaxProx)), 1)
if len(peers) > 0 {
// a random address at prox bin 0 is sent for lookup
randAddr := kademlia.RandomAddressAt(self.addr, proxLimit)
req := &retrieveRequestMsgData{
Key: storage.Key(randAddr[:]),
}
glog.V(logger.Detail).Infof("call any bee near %v (PO%03d) - messenger bee: %v", randAddr, proxLimit, peers[0])
peers[0].(*peer).retrieve(req)
} else {
glog.V(logger.Warn).Infof("no peer")
}
glog.V(logger.Detail).Infof("buzz kept alive")
} else {
glog.V(logger.Info).Infof("no need for more bees")
}
select {
case self.toggle <- need:
case <-self.quit:
return
}
glog.V(logger.Debug).Infof("queen's address: %v, population: %d (%d)", self.addr, self.kad.Count(), self.kad.DBCount())
}
}()
return
}
// keepAlive is a forever loop
// in its awake state it periodically triggers connection attempts
// by writing to self.more until Kademlia Table is saturated
// wake state is toggled by writing to self.toggle
// it restarts if the table becomes non-full again due to disconnections
func (self *Hive) keepAlive() {
alarm := time.NewTicker(time.Duration(self.callInterval)).C
for {
select {
case <-alarm:
if self.kad.DBCount() > 0 {
select {
case self.more <- true:
glog.V(logger.Debug).Infof("buzz wakeup")
default:
}
}
case need := <-self.toggle:
if alarm == nil && need {
alarm = time.NewTicker(time.Duration(self.callInterval)).C
}
if alarm != nil && !need {
alarm = nil
}
case <-self.quit:
return
}
}
}
func (self *Hive) Stop() error {
// closing toggle channel quits the updateloop
close(self.quit)
return self.kad.Save(self.path, saveSync)
}
// called at the end of a successful protocol handshake
func (self *Hive) addPeer(p *peer) error {
defer func() {
select {
case self.more <- true:
default:
}
}()
glog.V(logger.Detail).Infof("hi new bee %v", p)
err := self.kad.On(p, loadSync)
if err != nil {
return err
}
// self lookup (can be encoded as nil/zero key since peers addr known) + no id ()
// the most common way of saying hi in bzz is initiation of gossip
// let me know about anyone new from my hood , here is the storageradius
// to send the 6 byte self lookup
// we do not record as request or forward it, just reply with peers
p.retrieve(&retrieveRequestMsgData{})
glog.V(logger.Detail).Infof("'whatsup wheresdaparty' sent to %v", p)
return nil
}
// called after peer disconnected
func (self *Hive) removePeer(p *peer) {
glog.V(logger.Debug).Infof("bee %v removed", p)
self.kad.Off(p, saveSync)
select {
case self.more <- true:
default:
}
if self.kad.Count() == 0 {
glog.V(logger.Debug).Infof("empty, all bees gone")
}
}
// Retrieve a list of live peers that are closer to target than us
func (self *Hive) getPeers(target storage.Key, max int) (peers []*peer) {
var addr kademlia.Address
copy(addr[:], target[:])
for _, node := range self.kad.FindClosest(addr, max) {
peers = append(peers, node.(*peer))
}
return
}
// disconnects all the peers
func (self *Hive) DropAll() {
glog.V(logger.Info).Infof("dropping all bees")
for _, node := range self.kad.FindClosest(kademlia.Address{}, 0) {
node.Drop()
}
}
// contructor for kademlia.NodeRecord based on peer address alone
// TODO: should go away and only addr passed to kademlia
func newNodeRecord(addr *peerAddr) *kademlia.NodeRecord {
now := time.Now()
return &kademlia.NodeRecord{
Addr: addr.Addr,
Url: addr.String(),
Seen: now,
After: now,
}
}
// called by the protocol when receiving peerset (for target address)
// peersMsgData is converted to a slice of NodeRecords for Kademlia
// this is to store all thats needed
func (self *Hive) HandlePeersMsg(req *peersMsgData, from *peer) {
var nrs []*kademlia.NodeRecord
for _, p := range req.Peers {
nrs = append(nrs, newNodeRecord(p))
}
self.kad.Add(nrs)
}
// peer wraps the protocol instance to represent a connected peer
// it implements kademlia.Node interface
type peer struct {
*bzz // protocol instance running on peer connection
}
// protocol instance implements kademlia.Node interface (embedded peer)
func (self *peer) Addr() kademlia.Address {
return self.remoteAddr.Addr
}
func (self *peer) Url() string {
return self.remoteAddr.String()
}
// TODO take into account traffic
func (self *peer) LastActive() time.Time {
return self.lastActive
}
// reads the serialised form of sync state persisted as the 'Meta' attribute
// and sets the decoded syncState on the online node
func loadSync(record *kademlia.NodeRecord, node kademlia.Node) error {
p, ok := node.(*peer)
if !ok {
return fmt.Errorf("invalid type")
}
if record.Meta == nil {
glog.V(logger.Debug).Infof("no sync state for node record %v setting default", record)
p.syncState = &syncState{DbSyncState: &storage.DbSyncState{}}
return nil
}
state, err := decodeSync(record.Meta)
if err != nil {
return fmt.Errorf("error decoding kddb record meta info into a sync state: %v", err)
}
glog.V(logger.Detail).Infof("sync state for node record %v read from Meta: %s", record, string(*(record.Meta)))
p.syncState = state
return err
}
// callback when saving a sync state
func saveSync(record *kademlia.NodeRecord, node kademlia.Node) {
if p, ok := node.(*peer); ok {
meta, err := encodeSync(p.syncState)
if err != nil {
glog.V(logger.Warn).Infof("error saving sync state for %v: %v", node, err)
return
}
glog.V(logger.Detail).Infof("saved sync state for %v: %s", node, string(*meta))
record.Meta = meta
}
}
// the immediate response to a retrieve request,
// sends relevant peer data given by the kademlia hive to the requester
// TODO: remember peers sent for duration of the session, only new peers sent
func (self *Hive) peers(req *retrieveRequestMsgData) {
if req != nil && req.MaxPeers >= 0 {
var addrs []*peerAddr
if req.timeout == nil || time.Now().Before(*(req.timeout)) {
key := req.Key
// self lookup from remote peer
if storage.IsZeroKey(key) {
addr := req.from.Addr()
key = storage.Key(addr[:])
req.Key = nil
}
// get peer addresses from hive
for _, peer := range self.getPeers(key, int(req.MaxPeers)) {
addrs = append(addrs, peer.remoteAddr)
}
glog.V(logger.Debug).Infof("Hive sending %d peer addresses to %v. req.Id: %v, req.Key: %v", len(addrs), req.from, req.Id, req.Key.Log())
peersData := &peersMsgData{
Peers: addrs,
Key: req.Key,
Id: req.Id,
}
peersData.setTimeout(req.timeout)
req.from.peers(peersData)
}
}
}
func (self *Hive) String() string {
return self.kad.String()
}