lnrpc+routerrpc: disable custom tlv records via rpc

In order to prevent future unforeseen issues, we are temporarily
disabling the ability to send custom tlv records to the receiver of a
payment. Currently the receiver does not process or expose these
additional fields via rpc or internally, so they are being disabled
until the end-to-end flow is finished and fully validated.

lnrpc/routerrpc/router_backend.go

@@ -165,6 +165,7 @@ func (r *RouterBackend) QueryRoutes(ctx context.Context,
 		ignoredPairs[pair] = struct{}{}
 	}
 
+	var destTLV map[uint64][]byte
 	restrictions := &routing.RestrictParams{
 		FeeLimit: feeLimit,
 		ProbabilitySource: func(fromNode, toNode route.Vertex,
@@ -190,13 +191,13 @@ func (r *RouterBackend) QueryRoutes(ctx context.Context,
 				fromNode, toNode, amt,
 			)
 		},
-		DestPayloadTLV: len(in.DestTlv) != 0,
+		DestPayloadTLV: len(destTLV) != 0,
 	}
 
 	// If we have any TLV records destined for the final hop, then we'll
 	// attempt to decode them now into a form that the router can more
 	// easily manipulate.
-	destTlvRecords, err := tlv.MapToRecords(in.DestTlv)
+	destTlvRecords, err := tlv.MapToRecords(destTLV)
 	if err != nil {
 		return nil, err
 	}
@@ -332,11 +333,6 @@ func (r *RouterBackend) MarshallRoute(route *route.Route) (*lnrpc.Route, error)
 			chanCapacity = incomingAmt.ToSatoshis()
 		}
 
-		tlvMap, err := tlv.RecordsToMap(hop.TLVRecords)
-		if err != nil {
-			return nil, err
-		}
-
 		resp.Hops[i] = &lnrpc.Hop{
 			ChanId:           hop.ChannelID,
 			ChanCapacity:     int64(chanCapacity),
@@ -348,7 +344,6 @@ func (r *RouterBackend) MarshallRoute(route *route.Route) (*lnrpc.Route, error)
 			PubKey: hex.EncodeToString(
 				hop.PubKeyBytes[:],
 			),
-			TlvRecords: tlvMap,
 			TlvPayload: !hop.LegacyPayload,
 		}
 		incomingAmt = hop.AmtToForward
@@ -380,10 +375,7 @@ func (r *RouterBackend) UnmarshallHopByChannelLookup(hop *lnrpc.Hop,
 		return nil, fmt.Errorf("channel edge does not match expected node")
 	}
 
-	tlvRecords, err := tlv.MapToRecords(hop.TlvRecords)
+	var tlvRecords []tlv.Record
-	if err != nil {
-		return nil, err
-	}
 
 	return &route.Hop{
 		OutgoingTimeLock: hop.Expiry,
@@ -408,12 +400,6 @@ func UnmarshallKnownPubkeyHop(hop *lnrpc.Hop) (*route.Hop, error) {
 	copy(pubKeyBytes[:], pubKey)
 
 	var tlvRecords []tlv.Record
-	if hop.TlvRecords != nil {
-		tlvRecords, err = tlv.MapToRecords(hop.TlvRecords)
-		if err != nil {
-			return nil, err
-		}
-	}
 
 	return &route.Hop{
 		OutgoingTimeLock: hop.Expiry,
@@ -501,11 +487,10 @@ func (r *RouterBackend) extractIntentFromSendRequest(
 		return nil, errors.New("timeout_seconds must be specified")
 	}
 
-	if len(rpcPayReq.DestTlv) != 0 {
+	var destTLV map[uint64][]byte
+	if len(destTLV) != 0 {
 		var err error
-		payIntent.FinalDestRecords, err = tlv.MapToRecords(
+		payIntent.FinalDestRecords, err = tlv.MapToRecords(destTLV)
-			rpcPayReq.DestTlv,
-		)
 		if err != nil {
 			return nil, err
 		}

lnrpc/rpc.proto

@@ -1741,14 +1741,6 @@ message QueryRoutesRequest {
     A list of directed node pairs that will be ignored during path finding.
     */
     repeated NodePair ignored_pairs = 10;
-
-    /** 
-    An optional field that can be used to pass an arbitrary set of TLV records
-    to a peer which understands the new records. This can be used to pass
-    application specific data during the payment attempt. If the destination
-    does not support the specified recrods, and error will be returned.
-    */
-    map<uint64, bytes> dest_tlv = 11;
 }
 
 message NodePair {
@@ -1808,17 +1800,9 @@ message Hop {
 
     /** 
     If set to true, then this hop will be encoded using the new variable length
-    TLV format. Note that if any custom tlv_records below are specified, then
+    TLV format.
-    this field MUST be set to true for them to be encoded properly.
     */
     bool tlv_payload = 9 [json_name = "tlv_payload"];
-
-    /**
-    An optional set of key-value TLV records. This is useful within the context
-    of the SendToRoute call as it allows callers to specify arbitrary K-V pairs
-    to drop off at each hop within the onion.
-    */
-    map<uint64, bytes> tlv_records = 10 [json_name = "tlv_records"];
 }
 
 /**

lnrpc/rpc.swagger.json

@@ -2384,15 +2384,7 @@
         "tlv_payload": {
           "type": "boolean",
           "format": "boolean",
-          "description": "* \nIf set to true, then this hop will be encoded using the new variable length\nTLV format. Note that if any custom tlv_records below are specified, then\nthis field MUST be set to true for them to be encoded properly."
+          "description": "* \nIf set to true, then this hop will be encoded using the new variable length\nTLV format."
-        },
-        "tlv_records": {
-          "type": "object",
-          "additionalProperties": {
-            "type": "string",
-            "format": "byte"
-          },
-          "description": "*\nAn optional set of key-value TLV records. This is useful within the context\nof the SendToRoute call as it allows callers to specify arbitrary K-V pairs\nto drop off at each hop within the onion."
         }
       }
     },