diff --git a/htlcswitch/iterator.go b/htlcswitch/iterator.go
index 833aaff63..9387df6f8 100644
--- a/htlcswitch/iterator.go
+++ b/htlcswitch/iterator.go
@@ -3,6 +3,7 @@ package htlcswitch
 import (
 	"bytes"
 	"encoding/hex"
+	"io"
 
 	"github.com/btcsuite/golangcrypto/ripemd160"
 	"github.com/roasbeef/btcutil"
@@ -29,3 +30,14 @@ func (h HopID) String() string {
 func (h HopID) IsEqual(h2 HopID) bool {
 	return bytes.Equal(h[:], h2[:])
 }
+
+// HopIterator interface represent the entity which is able to give route
+// hops one by one. This interface is used to have an abstraction over the
+// algorithm which we use to determine the next hope in htlc route.
+type HopIterator interface {
+	// Next returns next hop if exist and nil if route is ended.
+	Next() *HopID
+
+	// Encode encodes iterator and writes it to the writer.
+	Encode(w io.Writer) error
+}
diff --git a/htlcswitch/link.go b/htlcswitch/link.go
index aee12639b..e37edc054 100644
--- a/htlcswitch/link.go
+++ b/htlcswitch/link.go
@@ -7,6 +7,8 @@ import (
 	"sync/atomic"
 	"time"
 
+	"io"
+
 	"github.com/lightningnetwork/lightning-onion"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/lnwallet"
@@ -26,6 +28,10 @@ type ChannelLinkConfig struct {
 	// packets to other peer which should handle it.
 	Switch *Switch
 
+	// DecodeOnion function responsible for decoding htlc Sphinx onion blob,
+	// and creating hop iterator which will give us next destination of htlc.
+	DecodeOnion func(r io.Reader, meta []byte) (HopIterator, error)
+
 	// Peer is a lightning network node with which we have the channel
 	// link opened.
 	Peer Peer