htlcswitch/iterator: use hop.Payload constructors

htlcswitch/hop/payload.go

@@ -0,0 +1,75 @@
+package hop
+
+import (
+	"encoding/binary"
+	"io"
+
+	"github.com/lightningnetwork/lightning-onion"
+	"github.com/lightningnetwork/lnd/lnwire"
+	"github.com/lightningnetwork/lnd/record"
+	"github.com/lightningnetwork/lnd/tlv"
+)
+
+// Payload encapsulates all information delivered to a hop in an onion payload.
+// A Hop can represent either a TLV or legacy payload. The primary forwarding
+// instruction can be accessed via ForwardingInfo, and additional records can be
+// accessed by other member functions.
+type Payload struct {
+	// FwdInfo holds the basic parameters required for HTLC forwarding, e.g.
+	// amount, cltv, and next hop.
+	FwdInfo ForwardingInfo
+}
+
+// NewLegacyPayload builds a Payload from the amount, cltv, and next hop
+// parameters provided by leegacy onion payloads.
+func NewLegacyPayload(f *sphinx.HopData) *Payload {
+	nextHop := binary.BigEndian.Uint64(f.NextAddress[:])
+
+	return &Payload{
+		FwdInfo: ForwardingInfo{
+			Network:         BitcoinNetwork,
+			NextHop:         lnwire.NewShortChanIDFromInt(nextHop),
+			AmountToForward: lnwire.MilliSatoshi(f.ForwardAmount),
+			OutgoingCTLV:    f.OutgoingCltv,
+		},
+	}
+}
+
+// NewPayloadFromReader builds a new Hop from the passed io.Reader. The reader
+// should correspond to the bytes encapsulated in a TLV onion payload.
+func NewPayloadFromReader(r io.Reader) (*Payload, error) {
+	var (
+		cid  uint64
+		amt  uint64
+		cltv uint32
+	)
+
+	tlvStream, err := tlv.NewStream(
+		record.NewAmtToFwdRecord(&amt),
+		record.NewLockTimeRecord(&cltv),
+		record.NewNextHopIDRecord(&cid),
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	err = tlvStream.Decode(r)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Payload{
+		FwdInfo: ForwardingInfo{
+			Network:         BitcoinNetwork,
+			NextHop:         lnwire.NewShortChanIDFromInt(cid),
+			AmountToForward: lnwire.MilliSatoshi(amt),
+			OutgoingCTLV:    cltv,
+		},
+	}, nil
+}
+
+// ForwardingInfo returns the basic parameters required for HTLC forwarding,
+// e.g. amount, cltv, and next hop.
+func (h *Payload) ForwardingInfo() ForwardingInfo {
+	return h.FwdInfo
+}