func (r *routingResolver) cacheSet(name string, val path.Path, rec *pb.IpnsEntry) {
	if r.cache == nil {
		return
	}

	// if completely unspecified, just use one minute
	ttl := DefaultResolverCacheTTL
	if rec.Ttl != nil {
		recttl := time.Duration(rec.GetTtl())
		if recttl >= 0 {
			ttl = recttl
		}
	}

	cacheTil := time.Now().Add(ttl)
	eol, ok := checkEOL(rec)
	if ok && eol.Before(cacheTil) {
		cacheTil = eol
	}

	r.cache.Add(name, cacheEntry{
		val: val,
		eol: cacheTil,
	})
}

func ipnsEntryDataForSig(e *pb.IpnsEntry) []byte {
	return bytes.Join([][]byte{
		e.Value,
		e.Validity,
		[]byte(fmt.Sprint(e.GetValidityType())),
	},
		[]byte{})
}

func checkEOL(e *pb.IpnsEntry) (time.Time, bool) {
	if e.GetValidityType() == pb.IpnsEntry_EOL {
		eol, err := u.ParseRFC3339(string(e.GetValidity()))
		if err != nil {
			return time.Time{}, false
		}
		return eol, true
	}
	return time.Time{}, false
}

func createRoutingEntryData(pk ci.PrivKey, val path.Path) ([]byte, error) {
	entry := new(pb.IpnsEntry)

	entry.Value = []byte(val)
	typ := pb.IpnsEntry_EOL
	entry.ValidityType = &typ
	entry.Validity = []byte(u.FormatRFC3339(time.Now().Add(time.Hour * 24)))

	sig, err := pk.Sign(ipnsEntryDataForSig(entry))
	if err != nil {
		return nil, err
	}
	entry.Signature = sig
	return proto.Marshal(entry)
}

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
}

// ValidateIpnsRecord implements ValidatorFunc and verifies that the
// given 'val' is an IpnsEntry and that that entry is valid.
func ValidateIpnsRecord(k key.Key, val []byte) error {
	entry := new(pb.IpnsEntry)
	err := proto.Unmarshal(val, entry)
	if err != nil {
		return err
	}
	switch entry.GetValidityType() {
	case pb.IpnsEntry_EOL:
		t, err := u.ParseRFC3339(string(entry.GetValidity()))
		if err != nil {
			log.Debug("Failed parsing time for ipns record EOL")
			return err
		}
		if time.Now().After(t) {
			return ErrExpiredRecord
		}
	default:
		return ErrUnrecognizedValidity
	}
	return 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
}

// resolveOnce implements resolver. Uses the IPFS routing system to
// resolve SFS-like names.
func (r *routingResolver) resolveOnce(ctx context.Context, name string) (path.Path, error) {
	log.Debugf("RoutingResolve: '%s'", name)
	hash, err := mh.FromB58String(name)
	if err != nil {
		log.Warning("RoutingResolve: bad input hash: [%s]\n", name)
		return "", err
	}
	// name should be a multihash. if it isn't, error out here.

	// use the routing system to get the name.
	// /ipns/<name>
	h := []byte("/ipns/" + string(hash))

	ipnsKey := key.Key(h)
	val, err := r.routing.GetValue(ctx, ipnsKey)
	if err != nil {
		log.Warning("RoutingResolve get failed.")
		return "", err
	}

	entry := new(pb.IpnsEntry)
	err = proto.Unmarshal(val, entry)
	if err != nil {
		return "", err
	}

	// name should be a public key retrievable from ipfs
	pubkey, err := routing.GetPublicKey(r.routing, ctx, hash)
	if err != nil {
		return "", err
	}

	hsh, _ := pubkey.Hash()
	log.Debugf("pk hash = %s", key.Key(hsh))

	// check sig with pk
	if ok, err := pubkey.Verify(ipnsEntryDataForSig(entry), entry.GetSignature()); err != nil || !ok {
		return "", fmt.Errorf("Invalid value. Not signed by PrivateKey corresponding to %v", pubkey)
	}

	// ok sig checks out. this is a valid name.

	// check for old style record:
	valh, err := mh.Cast(entry.GetValue())
	if err != nil {
		// Not a multihash, probably a new record
		return path.ParsePath(string(entry.GetValue()))
	} else {
		// Its an old style multihash record
		log.Warning("Detected old style multihash record")
		return path.FromKey(key.Key(valh)), nil
	}
}

func CreateRoutingEntryData(pk ci.PrivKey, val path.Path, seq uint64, eol time.Time) (*pb.IpnsEntry, error) {
	entry := new(pb.IpnsEntry)

	entry.Value = []byte(val)
	typ := pb.IpnsEntry_EOL
	entry.ValidityType = &typ
	entry.Sequence = proto.Uint64(seq)
	entry.Validity = []byte(u.FormatRFC3339(eol))

	sig, err := pk.Sign(ipnsEntryDataForSig(entry))
	if err != nil {
		return nil, err
	}
	entry.Signature = sig
	return entry, nil
}

// resolveOnce implements resolver. Uses the IPFS routing system to
// resolve SFS-like names.
func (r *routingResolver) resolveOnce(ctx context.Context, name string) (path.Path, error) {
	log.Debugf("RoutingResolve: '%s'", name)
	cached, ok := r.cacheGet(name)
	if ok {
		return cached, nil
	}

	name = strings.TrimPrefix(name, "/ipns/")
	hash, err := mh.FromB58String(name)
	if err != nil {
		// name should be a multihash. if it isn't, error out here.
		log.Warningf("RoutingResolve: bad input hash: [%s]\n", name)
		return "", err
	}

	// use the routing system to get the name.
	// /ipns/<name>
	h := []byte("/ipns/" + string(hash))

	var entry *pb.IpnsEntry
	var pubkey ci.PubKey

	resp := make(chan error, 2)
	go func() {
		ipnsKey := string(h)
		val, err := r.routing.GetValue(ctx, ipnsKey)
		if err != nil {
			log.Warning("RoutingResolve get failed.")
			resp <- err
			return
		}

		entry = new(pb.IpnsEntry)
		err = proto.Unmarshal(val, entry)
		if err != nil {
			resp <- err
			return
		}

		resp <- nil
	}()

	go func() {
		// name should be a public key retrievable from ipfs
		pubk, err := routing.GetPublicKey(r.routing, ctx, hash)
		if err != nil {
			resp <- err
			return
		}

		pubkey = pubk
		resp <- nil
	}()

	for i := 0; i < 2; i++ {
		err = <-resp
		if err != nil {
			return "", err
		}
	}

	// check sig with pk
	if ok, err := pubkey.Verify(ipnsEntryDataForSig(entry), entry.GetSignature()); err != nil || !ok {
		return "", fmt.Errorf("Invalid value. Not signed by PrivateKey corresponding to %v", pubkey)
	}

	// ok sig checks out. this is a valid name.

	// check for old style record:
	valh, err := mh.Cast(entry.GetValue())
	if err != nil {
		// Not a multihash, probably a new record
		p, err := path.ParsePath(string(entry.GetValue()))
		if err != nil {
			return "", err
		}

		r.cacheSet(name, p, entry)
		return p, nil
	} else {
		// Its an old style multihash record
		log.Warning("Detected old style multihash record")
		p := path.FromCid(cid.NewCidV0(valh))
		r.cacheSet(name, p, entry)
		return p, nil
	}
}