lnrpc: add payment cltv limit

lnrpc/rpc.proto

@@ -790,7 +790,14 @@ message SendRequest {
     any channel may be used.
     */
     uint64 outgoing_chan_id = 9;
+
+    /** 
+    An optional maximum total time lock for the route. If zero, there is no
+    maximum enforced.
+    */
+    uint32 cltv_limit = 10;
 }
+
 message SendResponse {
     string payment_error = 1 [json_name = "payment_error"];
     bytes payment_preimage = 2 [json_name = "payment_preimage"];

lnrpc/rpc.swagger.json

@@ -2977,6 +2977,11 @@
           "type": "string",
           "format": "uint64",
           "description": "*\nThe channel id of the channel that must be taken to the first hop. If zero,\nany channel may be used."
+        },
+        "cltv_limit": {
+          "type": "integer",
+          "format": "int64",
+          "description": "* \nAn optional maximum total time lock for the route. If zero, there is no\nmaximum enforced."
         }
       }
     },

rpcserver.go

@@ -2852,6 +2852,7 @@ func unmarshallSendToRouteRequest(req *lnrpc.SendToRouteRequest,
 type rpcPaymentIntent struct {
 	msat              lnwire.MilliSatoshi
 	feeLimit          lnwire.MilliSatoshi
+	cltvLimit         *uint32
 	dest              routing.Vertex
 	rHash             [32]byte
 	cltvDelta         uint16
@@ -2895,6 +2896,11 @@ func extractPaymentIntent(rpcPayReq *rpcPaymentRequest) (rpcPaymentIntent, error
 		payIntent.outgoingChannelID = &rpcPayReq.OutgoingChanId
 	}
 
+	// Take cltv limit from request if set.
+	if rpcPayReq.CltvLimit != 0 {
+		payIntent.cltvLimit = &rpcPayReq.CltvLimit
+	}
+
 	// If the payment request field isn't blank, then the details of the
 	// invoice are encoded entirely within the encoded payReq.  So we'll
 	// attempt to decode it, populating the payment accordingly.
@@ -3044,6 +3050,7 @@ func (r *rpcServer) dispatchPaymentIntent(
 			Target:            payIntent.dest,
 			Amount:            payIntent.msat,
 			FeeLimit:          payIntent.feeLimit,
+			CltvLimit:         payIntent.cltvLimit,
 			PaymentHash:       payIntent.rHash,
 			RouteHints:        payIntent.routeHints,
 			OutgoingChannelID: payIntent.outgoingChannelID,