// NewDHT creates a new DHT object with the given peer as the 'local' host
func NewDHT(ctx context.Context, h host.Host, dstore ds.ThreadSafeDatastore) *IpfsDHT {
dht := new(IpfsDHT)
dht.datastore = dstore
dht.self = h.ID()
dht.peerstore = h.Peerstore()
dht.host = h
// register for network notifs.
dht.host.Network().Notify((*netNotifiee)(dht))
dht.proc = goprocess.WithTeardown(func() error {
// remove ourselves from network notifs.
dht.host.Network().StopNotify((*netNotifiee)(dht))
return nil
})
dht.ctx = ctx
h.SetStreamHandler(ProtocolDHT, dht.handleNewStream)
dht.providers = NewProviderManager(dht.ctx, dht.self)
dht.proc.AddChild(dht.providers.proc)
goprocessctx.CloseAfterContext(dht.proc, ctx)
dht.routingTable = kb.NewRoutingTable(20, kb.ConvertPeerID(dht.self), time.Minute, dht.peerstore)
dht.birth = time.Now()
dht.Validator = make(record.Validator)
dht.Validator["pk"] = record.PublicKeyValidator
return dht
}
// FindPeersConnectedToPeer searches for peers directly connected to a given peer.
func (dht *IpfsDHT) FindPeersConnectedToPeer(ctx context.Context, id peer.ID) (<-chan peer.PeerInfo, error) {
peerchan := make(chan peer.PeerInfo, asyncQueryBuffer)
peersSeen := peer.Set{}
peers := dht.routingTable.NearestPeers(kb.ConvertPeerID(id), AlphaValue)
if len(peers) == 0 {
return nil, kb.ErrLookupFailure
}
// setup the Query
query := dht.newQuery(key.Key(id), func(ctx context.Context, p peer.ID) (*dhtQueryResult, error) {
pmes, err := dht.findPeerSingle(ctx, p, id)
if err != nil {
return nil, err
}
var clpeers []peer.PeerInfo
closer := pmes.GetCloserPeers()
for _, pbp := range closer {
pi := pb.PBPeerToPeerInfo(pbp)
// skip peers already seen
if _, found := peersSeen[pi.ID]; found {
continue
}
peersSeen[pi.ID] = struct{}{}
// if peer is connected, send it to our client.
if pb.Connectedness(*pbp.Connection) == inet.Connected {
select {
case <-ctx.Done():
return nil, ctx.Err()
case peerchan <- pi:
}
}
// if peer is the peer we're looking for, don't bother querying it.
// TODO maybe query it?
if pb.Connectedness(*pbp.Connection) != inet.Connected {
clpeers = append(clpeers, pi)
}
}
return &dhtQueryResult{closerPeers: clpeers}, nil
})
// run it! run it asynchronously to gen peers as results are found.
// this does no error checking
go func() {
if _, err := query.Run(ctx, peers); err != nil {
log.Debug(err)
}
// close the peerchan channel when done.
close(peerchan)
}()
return peerchan, nil
}
// FindPeer searches for a peer with given ID.
func (dht *IpfsDHT) FindPeer(ctx context.Context, id peer.ID) (peer.PeerInfo, error) {
defer log.EventBegin(ctx, "FindPeer", id).Done()
// Check if were already connected to them
if pi := dht.FindLocal(id); pi.ID != "" {
return pi, nil
}
peers := dht.routingTable.NearestPeers(kb.ConvertPeerID(id), AlphaValue)
if len(peers) == 0 {
return peer.PeerInfo{}, kb.ErrLookupFailure
}
// Sanity...
for _, p := range peers {
if p == id {
log.Debug("Found target peer in list of closest peers...")
return dht.peerstore.PeerInfo(p), nil
}
}
// setup the Query
query := dht.newQuery(key.Key(id), func(ctx context.Context, p peer.ID) (*dhtQueryResult, error) {
notif.PublishQueryEvent(ctx, ¬if.QueryEvent{
Type: notif.SendingQuery,
ID: p,
})
pmes, err := dht.findPeerSingle(ctx, p, id)
if err != nil {
return nil, err
}
closer := pmes.GetCloserPeers()
clpeerInfos := pb.PBPeersToPeerInfos(closer)
// see it we got the peer here
for _, npi := range clpeerInfos {
if npi.ID == id {
return &dhtQueryResult{
peer: npi,
success: true,
}, nil
}
}
notif.PublishQueryEvent(ctx, ¬if.QueryEvent{
Type: notif.PeerResponse,
Responses: pointerizePeerInfos(clpeerInfos),
})
return &dhtQueryResult{closerPeers: clpeerInfos}, nil
})
// run it!
result, err := query.Run(ctx, peers)
if err != nil {
return peer.PeerInfo{}, err
}
log.Debugf("FindPeer %v %v", id, result.success)
if result.peer.ID == "" {
return peer.PeerInfo{}, routing.ErrNotFound
}
return result.peer, nil
}