func (dht *IpfsDHT) getPublicKeyFromNode(ctx context.Context, p peer.ID) (ci.PubKey, error) {
// check locally, just in case...
pk := dht.peerstore.PubKey(p)
if pk != nil {
return pk, nil
}
pkkey := routing.KeyForPublicKey(p)
pmes, err := dht.getValueSingle(ctx, p, pkkey)
if err != nil {
return nil, err
}
// node doesn't have key :(
record := pmes.GetRecord()
if record == nil {
return nil, fmt.Errorf("node not responding with its public key: %s", p)
}
// Success! We were given the value. we don't need to check
// validity because a) we can't. b) we know the hash of the
// key we're looking for.
val := record.GetValue()
log.Debug("dht got a value from other peer.")
pk, err = ci.UnmarshalPublicKey(val)
if err != nil {
return nil, err
}
id, err := peer.IDFromPublicKey(pk)
if err != nil {
return nil, err
}
if id != p {
return nil, fmt.Errorf("public key does not match id: %s", p)
}
// ok! it's valid. we got it!
log.Debugf("dht got public key from node itself.")
return pk, nil
}
func (dht *IpfsDHT) GetPublicKey(ctx context.Context, p peer.ID) (ci.PubKey, error) {
log.Debugf("getPublicKey for: %s", p)
// check locally.
pk := dht.peerstore.PubKey(p)
if pk != nil {
return pk, nil
}
// ok, try the node itself. if they're overwhelmed or slow we can move on.
ctxT, cancelFunc := ctxfrac.WithDeadlineFraction(ctx, 0.3)
defer cancelFunc()
if pk, err := dht.getPublicKeyFromNode(ctx, p); err == nil {
err := dht.peerstore.AddPubKey(p, pk)
if err != nil {
return pk, err
}
return pk, nil
}
// last ditch effort: let's try the dht.
log.Debugf("pk for %s not in peerstore, and peer failed. trying dht.", p)
pkkey := routing.KeyForPublicKey(p)
val, err := dht.GetValue(ctxT, pkkey)
if err != nil {
log.Warning("Failed to find requested public key.")
return nil, err
}
pk, err = ci.UnmarshalPublicKey(val)
if err != nil {
log.Debugf("Failed to unmarshal public key: %s", err)
return nil, err
}
return pk, dht.peerstore.AddPubKey(p, pk)
}