lnrpc: surface blinded payment fields in hops

lnrpc/lightning.proto

@@ -3116,6 +3116,32 @@ message Hop {
 
     // The payment metadata to send along with the payment to the payee.
     bytes metadata = 13;
+
+    /*
+    Blinding point is an optional blinding point included for introduction
+    nodes in blinded paths. This field is mandatory for hops that represents
+    the introduction point in a blinded path.
+    */
+    bytes blinding_point = 14;
+
+    /*
+    Encrypted data is a receiver-produced blob of data that provides hops
+    in a blinded route with forwarding data. As this data is encrypted by
+    the recipient, we will not be able to parse it - it is essentially an
+    arbitrary blob of data from our node's perspective. This field is
+    mandatory for all hops in a blinded path, including the introduction
+    node.
+    */
+    bytes encrypted_data = 15;
+
+    /*
+    The total amount that is sent to the recipient (possibly across multiple
+    HTLCs), as specified by the sender when making a payment to a blinded path.
+    This value is only set in the final hop payload of a blinded payment. This
+    value is analogous to the MPPRecord that is used for regular (non-blinded)
+    MPP payments.
+    */
+    uint64 total_amt_msat = 16;
 }
 
 message MPPRecord {

lnrpc/lightning.swagger.json

@@ -5045,6 +5045,21 @@
           "type": "string",
           "format": "byte",
           "description": "The payment metadata to send along with the payment to the payee."
+        },
+        "blinding_point": {
+          "type": "string",
+          "format": "byte",
+          "description": "Blinding point is an optional blinding point included for introduction\nnodes in blinded paths. This field is mandatory for hops that represents\nthe introduction point in a blinded path."
+        },
+        "encrypted_data": {
+          "type": "string",
+          "format": "byte",
+          "description": "Encrypted data is a receiver-produced blob of data that provides hops\nin a blinded route with forwarding data. As this data is encrypted by\nthe recipient, we will not be able to parse it - it is essentially an\narbitrary blob of data from our node's perspective. This field is\nmandatory for all hops in a blinded path, including the introduction\nnode."
+        },
+        "total_amt_msat": {
+          "type": "string",
+          "format": "uint64",
+          "description": "The total amount that is sent to the recipient (possibly across multiple\nHTLCs), as specified by the sender when making a payment to a blinded path.\nThis value is only set in the final hop payload of a blinded payment. This\nvalue is analogous to the MPPRecord that is used for regular (non-blinded)\nMPP payments."
         }
       }
     },

lnrpc/routerrpc/router.swagger.json

@@ -873,6 +873,21 @@
           "type": "string",
           "format": "byte",
           "description": "The payment metadata to send along with the payment to the payee."
+        },
+        "blinding_point": {
+          "type": "string",
+          "format": "byte",
+          "description": "Blinding point is an optional blinding point included for introduction\nnodes in blinded paths. This field is mandatory for hops that represents\nthe introduction point in a blinded path."
+        },
+        "encrypted_data": {
+          "type": "string",
+          "format": "byte",
+          "description": "Encrypted data is a receiver-produced blob of data that provides hops\nin a blinded route with forwarding data. As this data is encrypted by\nthe recipient, we will not be able to parse it - it is essentially an\narbitrary blob of data from our node's perspective. This field is\nmandatory for all hops in a blinded path, including the introduction\nnode."
+        },
+        "total_amt_msat": {
+          "type": "string",
+          "format": "uint64",
+          "description": "The total amount that is sent to the recipient (possibly across multiple\nHTLCs), as specified by the sender when making a payment to a blinded path.\nThis value is only set in the final hop payload of a blinded payment. This\nvalue is analogous to the MPPRecord that is used for regular (non-blinded)\nMPP payments."
         }
       }
     },

lnrpc/routerrpc/router_backend.go

@@ -424,6 +424,13 @@ func (r *RouterBackend) MarshallRoute(route *route.Route) (*lnrpc.Route, error)
 			TlvPayload:    !hop.LegacyPayload,
 			MppRecord:     mpp,
 			Metadata:      hop.Metadata,
+			EncryptedData: hop.EncryptedData,
+			TotalAmtMsat:  uint64(hop.TotalAmtMsat),
+		}
+
+		if hop.BlindingPoint != nil {
+			blinding := hop.BlindingPoint.SerializeCompressed()
+			resp.Hops[i].BlindingPoint = blinding
 		}
 		incomingAmt = hop.AmtToForward
 	}
@@ -451,7 +458,7 @@ func UnmarshallHopWithPubkey(rpcHop *lnrpc.Hop, pubkey route.Vertex) (*route.Hop
 		return nil, err
 	}
 
-	return &route.Hop{
+	hop := &route.Hop{
 		OutgoingTimeLock: rpcHop.Expiry,
 		AmtToForward:     lnwire.MilliSatoshi(rpcHop.AmtToForwardMsat),
 		PubKeyBytes:      pubkey,
@@ -460,7 +467,26 @@ func UnmarshallHopWithPubkey(rpcHop *lnrpc.Hop, pubkey route.Vertex) (*route.Hop
 		LegacyPayload:    false,
 		MPP:              mpp,
 		AMP:              amp,
-	}, nil
+		EncryptedData:    rpcHop.EncryptedData,
+		TotalAmtMsat:     lnwire.MilliSatoshi(rpcHop.TotalAmtMsat),
+	}
+
+	haveBlindingPoint := len(rpcHop.BlindingPoint) != 0
+	if haveBlindingPoint {
+		hop.BlindingPoint, err = btcec.ParsePubKey(
+			rpcHop.BlindingPoint,
+		)
+		if err != nil {
+			return nil, fmt.Errorf("blinding point: %w", err)
+		}
+	}
+
+	if haveBlindingPoint && len(rpcHop.EncryptedData) == 0 {
+		return nil, errors.New("encrypted data should be present if " +
+			"blinding point is provided")
+	}
+
+	return hop, nil
 }
 
 // UnmarshallHop unmarshalls an rpc hop that may or may not contain a node