lnrpc+routing: add edges and nodes restrictions to query routes

This commit allows the execution of QueryRoutes to be controlled using
lists of black-listed edges and nodes. Any path returned will not pass
through the edges and/or nodes on the list.

lnrpc/rpc.proto

@@ -1480,7 +1480,31 @@ message QueryRoutesRequest {
     send the payment.
     */
     FeeLimit fee_limit = 5;
+
+    /**
+    A list of nodes to ignore during path finding.
+    */
+    repeated bytes ignored_nodes = 6;
+
+    /**
+    A list of edges to ignore during path finding.
+    */
+    repeated EdgeLocator ignored_edges = 7;
 }
+
+message EdgeLocator {
+    /// The short channel id of this edge.
+    uint64 channel_id = 1;
+
+    /**
+    The direction of this edge. If direction_reverse is false, the direction
+    of this edge is from the channel endpoint with the lexicographically smaller
+    pub key to the endpoint with the larger pub key. If direction_reverse is
+    is true, the edge goes the other way.
+    */
+    bool direction_reverse = 2;
+}
+
 message QueryRoutesResponse {
     repeated Route routes = 1 [json_name = "routes"];
 }

lnrpc/rpc.swagger.json

@@ -593,6 +593,17 @@
             "required": false,
             "type": "string",
             "format": "int64"
+          },
+          {
+            "name": "ignored_nodes",
+            "description": "*\nA list of nodes to ignore during path finding.",
+            "in": "query",
+            "required": false,
+            "type": "array",
+            "items": {
+              "type": "string",
+              "format": "byte"
+            }
           }
         ],
         "tags": [