116 lines
2.7 KiB
Go
116 lines
2.7 KiB
Go
package dht
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import (
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"context"
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"fmt"
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"strings"
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"github.com/libp2p/go-libp2p-core/peer"
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cid "github.com/ipfs/go-cid"
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logging "github.com/ipfs/go-log"
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pb "github.com/libp2p/go-libp2p-kad-dht/pb"
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kb "github.com/libp2p/go-libp2p-kbucket"
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notif "github.com/libp2p/go-libp2p-routing/notifications"
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)
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func tryFormatLoggableKey(k string) (string, error) {
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if len(k) == 0 {
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return "", fmt.Errorf("loggableKey is empty")
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}
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var proto, cstr string
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if k[0] == '/' {
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// it's a path (probably)
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protoEnd := strings.IndexByte(k[1:], '/')
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if protoEnd < 0 {
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return k, fmt.Errorf("loggableKey starts with '/' but is not a path: %x", k)
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}
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proto = k[1 : protoEnd+1]
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cstr = k[protoEnd+2:]
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} else {
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proto = "provider"
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cstr = k
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}
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c, err := cid.Cast([]byte(cstr))
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if err != nil {
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return "", fmt.Errorf("loggableKey could not cast key to a CID: %x %v", k, err)
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}
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return fmt.Sprintf("/%s/%s", proto, c.String()), nil
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}
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func loggableKey(k string) logging.LoggableMap {
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newKey, err := tryFormatLoggableKey(k)
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if err != nil {
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logger.Debug(err)
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} else {
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k = newKey
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}
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return logging.LoggableMap{
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"key": k,
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}
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}
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// Kademlia 'node lookup' operation. Returns a channel of the K closest peers
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// to the given key
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func (dht *IpfsDHT) GetClosestPeers(ctx context.Context, key string) (<-chan peer.ID, error) {
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e := logger.EventBegin(ctx, "getClosestPeers", loggableKey(key))
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tablepeers := dht.routingTable.NearestPeers(kb.ConvertKey(key), AlphaValue)
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if len(tablepeers) == 0 {
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return nil, kb.ErrLookupFailure
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}
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out := make(chan peer.ID, KValue)
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// since the query doesnt actually pass our context down
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// we have to hack this here. whyrusleeping isnt a huge fan of goprocess
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parent := ctx
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query := dht.newQuery(key, func(ctx context.Context, p peer.ID) (*dhtQueryResult, error) {
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// For DHT query command
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notif.PublishQueryEvent(parent, ¬if.QueryEvent{
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Type: notif.SendingQuery,
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ID: p,
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})
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pmes, err := dht.findPeerSingle(ctx, p, peer.ID(key))
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if err != nil {
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logger.Debugf("error getting closer peers: %s", err)
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return nil, err
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}
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peers := pb.PBPeersToPeerInfos(pmes.GetCloserPeers())
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// For DHT query command
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notif.PublishQueryEvent(parent, ¬if.QueryEvent{
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Type: notif.PeerResponse,
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ID: p,
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Responses: peers,
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})
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return &dhtQueryResult{closerPeers: peers}, nil
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})
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go func() {
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defer close(out)
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defer e.Done()
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// run it!
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res, err := query.Run(ctx, tablepeers)
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if err != nil {
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logger.Debugf("closestPeers query run error: %s", err)
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}
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if res != nil && res.queriedSet != nil {
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sorted := kb.SortClosestPeers(res.queriedSet.Peers(), kb.ConvertKey(key))
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if len(sorted) > KValue {
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sorted = sorted[:KValue]
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}
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for _, p := range sorted {
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out <- p
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}
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}
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}()
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return out, nil
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}
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