// FIXME(brian): is this method meant to simulate putting a value into the network?
func (c *client) PutValue(ctx context.Context, key key.Key, val []byte) error {
log.Debugf("PutValue: %s", key)
rec := new(dhtpb.Record)
rec.Value = val
rec.Key = proto.String(string(key))
rec.TimeReceived = proto.String(u.FormatRFC3339(time.Now()))
data, err := proto.Marshal(rec)
if err != nil {
return err
}
return c.datastore.Put(key.DsKey(), data)
}
func verify(ps peer.Peerstore, r *dhtpb.Record) error {
v := make(record.Validator)
v["pk"] = record.PublicKeyValidator
p := peer.ID(r.GetAuthor())
pk := ps.PubKey(p)
if pk == nil {
return fmt.Errorf("do not have public key for %s", p)
}
if err := record.CheckRecordSig(r, pk); err != nil {
return err
}
if err := v.VerifyRecord(r); err != nil {
return err
}
return nil
}
// verifyRecordLocally attempts to verify a record. if we do not have the public
// key, we fail. we do not search the dht.
func (dht *IpfsDHT) verifyRecordLocally(r *pb.Record) error {
if len(r.Signature) > 0 {
// First, validate the signature
p := peer.ID(r.GetAuthor())
pk := dht.peerstore.PubKey(p)
if pk == nil {
return fmt.Errorf("do not have public key for %s", p)
}
if err := record.CheckRecordSig(r, pk); err != nil {
return err
}
}
return dht.Validator.VerifyRecord(r)
}
func (c *offlineRouting) GetValue(ctx context.Context, key key.Key) ([]byte, error) {
v, err := c.datastore.Get(key.DsKey())
if err != nil {
return nil, err
}
byt, ok := v.([]byte)
if !ok {
return nil, errors.New("value stored in datastore not []byte")
}
rec := new(pb.Record)
err = proto.Unmarshal(byt, rec)
if err != nil {
return nil, err
}
return rec.GetValue(), nil
}
// verifyRecordOnline verifies a record, searching the DHT for the public key
// if necessary. The reason there is a distinction in the functions is that
// retrieving arbitrary public keys from the DHT as a result of passively
// receiving records (e.g. through a PUT_VALUE or ADD_PROVIDER) can cause a
// massive amplification attack on the dht. Use with care.
func (dht *IpfsDHT) verifyRecordOnline(ctx context.Context, r *pb.Record) error {
if len(r.Signature) > 0 {
// get the public key, search for it if necessary.
p := peer.ID(r.GetAuthor())
pk, err := dht.GetPublicKey(ctx, p)
if err != nil {
return err
}
err = record.CheckRecordSig(r, pk)
if err != nil {
return err
}
}
return dht.Validator.VerifyRecord(r)
}
// FIXME(brian): is this method meant to simulate getting a value from the network?
func (c *client) GetValue(ctx context.Context, key key.Key) ([]byte, error) {
log.Debugf("GetValue: %s", key)
v, err := c.datastore.Get(key.DsKey())
if err != nil {
return nil, err
}
data, ok := v.([]byte)
if !ok {
return nil, errors.New("could not cast value from datastore")
}
rec := new(dhtpb.Record)
err = proto.Unmarshal(data, rec)
if err != nil {
return nil, err
}
return rec.GetValue(), nil
}
func (p *ipnsPublisher) getPreviousSeqNo(ctx context.Context, ipnskey key.Key) (uint64, error) {
prevrec, err := p.ds.Get(ipnskey.DsKey())
if err != nil && err != ds.ErrNotFound {
// None found, lets start at zero!
return 0, err
}
var val []byte
if err == nil {
prbytes, ok := prevrec.([]byte)
if !ok {
return 0, fmt.Errorf("unexpected type returned from datastore: %#v", prevrec)
}
dhtrec := new(dhtpb.Record)
err := proto.Unmarshal(prbytes, dhtrec)
if err != nil {
return 0, err
}
val = dhtrec.GetValue()
} else {
// try and check the dht for a record
ctx, cancel := context.WithTimeout(ctx, time.Second*30)
defer cancel()
rv, err := p.routing.GetValue(ctx, ipnskey)
if err != nil {
// no such record found, start at zero!
return 0, nil
}
val = rv
}
e := new(pb.IpnsEntry)
err = proto.Unmarshal(val, e)
if err != nil {
return 0, err
}
return e.GetSequence(), nil
}
func (rp *Republisher) getLastVal(k key.Key) (path.Path, uint64, error) {
ival, err := rp.ds.Get(k.DsKey())
if err != nil {
// not found means we dont have a previously published entry
return "", 0, errNoEntry
}
val := ival.([]byte)
dhtrec := new(dhtpb.Record)
err = proto.Unmarshal(val, dhtrec)
if err != nil {
return "", 0, err
}
// extract published data from record
e := new(pb.IpnsEntry)
err = proto.Unmarshal(dhtrec.GetValue(), e)
if err != nil {
return "", 0, err
}
return path.Path(e.Value), e.GetSequence(), nil
}
// VerifyRecord checks a record and ensures it is still valid.
// It runs needed validators
func (v Validator) VerifyRecord(r *pb.Record) error {
// Now, check validity func
parts := strings.Split(r.GetKey(), "/")
if len(parts) < 3 {
log.Infof("Record key does not have validator: %s", key.Key(r.GetKey()))
return nil
}
val, ok := v[parts[1]]
if !ok {
log.Infof("Unrecognized key prefix: %s", parts[1])
return ErrInvalidRecordType
}
return val.Func(key.Key(r.GetKey()), r.GetValue())
}
// MakePutRecord creates and signs a dht record for the given key/value pair
func MakePutRecord(sk ci.PrivKey, key key.Key, value []byte, sign bool) (*pb.Record, error) {
record := new(pb.Record)
record.Key = proto.String(string(key))
record.Value = value
pkh, err := sk.GetPublic().Hash()
if err != nil {
return nil, err
}
record.Author = proto.String(string(pkh))
if sign {
blob := RecordBlobForSig(record)
sig, err := sk.Sign(blob)
if err != nil {
return nil, err
}
record.Signature = sig
}
return record, nil
}
func (dht *IpfsDHT) checkLocalDatastore(k key.Key) (*pb.Record, error) {
log.Debugf("%s handleGetValue looking into ds", dht.self)
dskey := k.DsKey()
iVal, err := dht.datastore.Get(dskey)
log.Debugf("%s handleGetValue looking into ds GOT %v", dht.self, iVal)
if err == ds.ErrNotFound {
return nil, nil
}
// if we got an unexpected error, bail.
if err != nil {
return nil, err
}
// if we have the value, send it back
log.Debugf("%s handleGetValue success!", dht.self)
byts, ok := iVal.([]byte)
if !ok {
return nil, fmt.Errorf("datastore had non byte-slice value for %v", dskey)
}
rec := new(pb.Record)
err = proto.Unmarshal(byts, rec)
if err != nil {
log.Debug("Failed to unmarshal dht record from datastore")
return nil, err
}
// if its our record, dont bother checking the times on it
if peer.ID(rec.GetAuthor()) == dht.self {
return rec, nil
}
var recordIsBad bool
recvtime, err := u.ParseRFC3339(rec.GetTimeReceived())
if err != nil {
log.Info("either no receive time set on record, or it was invalid: ", err)
recordIsBad = true
}
if time.Now().Sub(recvtime) > MaxRecordAge {
log.Debug("old record found, tossing.")
recordIsBad = true
}
// NOTE: we do not verify the record here beyond checking these timestamps.
// we put the burden of checking the records on the requester as checking a record
// may be computationally expensive
if recordIsBad {
err := dht.datastore.Delete(dskey)
if err != nil {
log.Error("Failed to delete bad record from datastore: ", err)
}
return nil, nil // can treat this as not having the record at all
}
return rec, nil
}
// RecordBlobForSig returns the blob protected by the record signature
func RecordBlobForSig(r *pb.Record) []byte {
k := []byte(r.GetKey())
v := []byte(r.GetValue())
a := []byte(r.GetAuthor())
return bytes.Join([][]byte{k, v, a}, []byte{})
}
