add askrene-disable-channel

Changelog-EXPERIMENTAL: askrene: add askrene-disable-channel RPC

Signed-off-by: Lagrang3 <[email protected]>

Author: Lagrang3

doc/Makefile

@@ -8,6 +8,7 @@ GENERATE_MARKDOWN := doc/lightning-addgossip.7 \
 	doc/lightning-addpsbtoutput.7 \
 	doc/lightning-askrene-create-channel.7 \
 	doc/lightning-askrene-disable-node.7 \
+	doc/lightning-askrene-disable-channel.7 \
 	doc/lightning-askrene-inform-channel.7 \
 	doc/lightning-askrene-listlayers.7 \
 	doc/lightning-askrene-reserve.7 \

doc/schemas/lightning-askrene-disable-channel.json

@@ -0,0 +1,57 @@
+{
+  "$schema": "../rpc-schema-draft.json",
+  "type": "object",
+  "additionalProperties": false,
+  "rpc": "askrene-disable-channel",
+  "title": "Command to disable a channel in a layer (EXPERIMENTAL)",
+  "description": [
+    "WARNING: experimental, so API may change.",
+    "",
+    "The **askrene-disable-channel** RPC command tells askrene to disable a channel whenever the given layer is used.  This is mainly useful to force the use of alternate paths."
+  ],
+  "request": {
+    "required": [
+      "layer",
+      "short_channel_id"
+    ],
+    "properties": {
+      "layer": {
+        "type": "string",
+        "description": [
+          "The name of the layer to apply this change to."
+        ]
+      },
+      "short_channel_id": {
+        "type": "short_channel_id",
+        "description": [
+          "The channel to disable."
+        ]
+      },
+      "direction": {
+        "type": "u32",
+        "description": [
+          "The direction of the channel. If the direction is not specified then both directions are disabled."
+        ]
+      }
+    }
+  },
+  "response": {
+    "required": [],
+    "properties": {}
+  },
+  "see_also": [
+    "lightning-getroutes(7)",
+    "lightning-askrene-create-channel(7)",
+    "lightning-askrene-inform-channel(7)",
+    "lightning-askrene-disable-node(7)",
+    "lightning-askrene-listlayers(7)",
+    "lightning-askrene-age(7)"
+  ],
+  "author": [
+    "Rusty Russell <<[email protected]>> is mainly responsible."
+  ],
+  "resources": [
+    "Main web site: <https://github.com/ElementsProject/lightning>"
+  ]
+}
+

doc/schemas/lightning-askrene-listlayers.json

@@ -32,7 +32,7 @@
           "additionalProperties": false,
           "required": [
             "layer",
-            "disabled_nodes",
+            "disabled",
             "created_channels",
             "constraints"
           ],
@@ -43,13 +43,23 @@
                 "The name of the layer."
               ]
             },
-            "disabled_nodes": {
+            "disabled": {
               "type": "array",
               "items": {
-                "type": "pubkey",
-                "description": [
-                  "The id of the disabled node."
-                ]
+                "oneOf": [
+                  {
+                    "type": "pubkey",
+                    "description": [
+                      "The id of the disabled node."
+                    ]
+                  },
+                  {
+                    "type": "short_channel_id_dir",
+                    "description": [
+                      "The short channel id of the disabled channel."
+                    ]
+                  }
+		]
               }
             },
             "created_channels": {

plugins/askrene/askrene.c

@@ -881,6 +881,44 @@ static struct command_result *json_askrene_inform_channel(struct command *cmd,
 	return command_finished(cmd, response);
 }
 
+static struct command_result *json_askrene_disable_channel(struct command *cmd,
+							const char *buffer,
+							const jsmntok_t *params)
+{
+	struct short_channel_id *scid;
+	int *direction;
+	const char *layername;
+	struct layer *layer;
+	struct json_stream *response;
+	struct askrene *askrene = get_askrene(cmd->plugin);
+
+	if (!param(cmd, buffer, params,
+		   p_req("layer", param_layername, &layername),
+		   p_req("short_channel_id", param_short_channel_id, &scid),
+		   p_opt("direction", param_zero_or_one, &direction),
+		   NULL))
+		return command_param_failed();
+
+	layer = find_layer(askrene, layername);
+	if (!layer)
+		layer = new_layer(askrene, layername);
+
+	struct short_channel_id_dir scidd = {.scid = *scid};
+	if (direction) {
+		scidd.dir = *direction;
+		layer_add_disabled_channel(layer, &scidd);
+	} else {
+		/* If no direction is provided we disable both. */
+		scidd.dir = 0;
+		layer_add_disabled_channel(layer, &scidd);
+		scidd.dir = 1;
+		layer_add_disabled_channel(layer, &scidd);
+	}
+
+	response = jsonrpc_stream_success(cmd);
+	return command_finished(cmd, response);
+}
+
 static struct command_result *json_askrene_disable_node(struct command *cmd,
 							const char *buffer,
 							const jsmntok_t *params)
@@ -983,6 +1021,10 @@ static const struct plugin_command commands[] = {
 		"askrene-age",
 		json_askrene_age,
 	},
+	{
+		"askrene-disable-channel",
+		json_askrene_disable_channel,
+	},
 };
 
 static void askrene_markmem(struct plugin *plugin, struct htable *memtable)

plugins/askrene/layer.c

@@ -306,6 +306,15 @@ void layer_add_disabled_node(struct layer *layer, const struct node_id *node)
 	tal_arr_expand(&layer->disabled, ex);
 }
 
+void layer_add_disabled_channel(struct layer *layer,
+				const struct short_channel_id_dir *scidd)
+{
+	struct route_exclusion ex;
+	ex.type = EXCLUDE_CHANNEL;
+	ex.u.chan_id = *scidd;
+	tal_arr_expand(&layer->disabled, ex);
+}
+
 void layer_add_localmods(const struct layer *layer,
 			 const struct gossmap *gossmap,
 			 bool zero_cost,

plugins/askrene/layer.h

@@ -102,6 +102,10 @@ size_t layer_trim_constraints(struct layer *layer, u64 cutoff);
 /* Add a disabled node to a layer. */
 void layer_add_disabled_node(struct layer *layer, const struct node_id *node);
 
+/* Add a disabled channel to a layer. */
+void layer_add_disabled_channel(struct layer *layer,
+				const struct short_channel_id_dir *scidd);
+
 /* Print out a json object per layer, or all if layer is NULL */
 void json_add_layers(struct json_stream *js,
 		     struct askrene *askrene,

tests/test_askrene.py

@@ -16,11 +16,11 @@ def test_layers(node_factory):
     assert l2.rpc.askrene_listlayers('test_layers') == {'layers': []}
 
     expect = {'layer': 'test_layers',
-              'disabled_nodes': [],
+              'disabled': [],
               'created_channels': [],
               'constraints': []}
     l2.rpc.askrene_disable_node('test_layers', l1.info['id'])
-    expect['disabled_nodes'].append(l1.info['id'])
+    expect['disabled'].append(l1.info['id'])
     assert l2.rpc.askrene_listlayers('test_layers') == {'layers': [expect]}
     assert l2.rpc.askrene_listlayers() == {'layers': [expect]}
     assert l2.rpc.askrene_listlayers('test_layers2') == {'layers': []}