renepay: use getroutes

Changelog-Added: renepay: use external call to [askrene-]getroutes instead of computing routes internally.

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

Author: Lagrang3

plugins/renepay/mods.c

@@ -652,12 +652,37 @@ REGISTER_PAYMENT_MODIFIER(blindedhints, blindedhints_cb);
 
 
 /*****************************************************************************
- * compute_routes
+ * getroutes
  *
- * Compute the payment routes.
+ * Call askrene-getroutes
  */
 
-static struct command_result *compute_routes_cb(struct payment *payment)
+static struct command_result *getroutes_done(struct command *cmd,
+	const char *method,
+	const char *buf,
+	const jsmntok_t *tok,
+	struct payment *payment)
+{
+	// FIXME: read the response, build the routes
+	return payment_continue(payment);
+}
+
+static struct command_result *getroutes_fail(struct command *cmd,
+	const char *method,
+	const char *buf,
+	const jsmntok_t *tok,
+	struct payment *payment)
+{
+	// FIXME: read the response
+	// if can we do something about his failure:
+	// 	disable channels or add biases
+	// else:
+	// 	return payment_fail(payment, PAY_STOPPED_RETRYING, "getroutes
+	// 	failed to find a feasible solution %s", explain_error(buf, tok));
+	return payment_continue(payment);
+}
+
+static struct command_result *getroutes_cb(struct payment *payment)
 {
 	assert(payment->status == PAYMENT_PENDING);
 	struct routetracker *routetracker = payment->routetracker;
@@ -699,6 +724,57 @@ static struct command_result *compute_routes_cb(struct payment *payment)
 		return payment_continue(payment);
 	}
 
+	/* FIXME:
+	 * call getroutes:
+	 * 	input: source, destination, amount, maxfee, final_cltv,
+	 * 	maxdelay, layers: [auto.localchans, auto.sourcefree,
+	 * 	thispaymenthints, thispaymentexclude, renepayknowledge]
+	 *
+	 * possible outcomes:
+	 * 	success: then continue
+	 * 	fail with hint: try to fix and retry or fail payment
+	 * */
+	struct command *cmd = payment_command(payment);
+	struct out_req *req = jsonrpc_request_start(cmd,
+		"getroutes", getroutes_done, getroutes_fail, payment);
+
+	// FIXME: add an algorithm selection in askrene such that we could
+	// retrieve a single path route if necessary, see issue 8042
+	// FIXME: register layers before using then:
+	// 	-> register RENEPAY_LAYER on plugin startup
+	// 	-> register payment->payment_layer when payment is created
+	// 	-> payment_layer should auto clean
+	// 	-> register payment->command_layer when the payment execution
+	// 	starts
+	// 	-> command_layer should auto clean
+
+	json_add_node_id(req->js, "source", &pay_plugin->my_id);
+	json_add_node_id(req->js, "destination", payment->routing_destination);
+	json_add_amount_msat(req->js, "amount_msat", remaining);
+	json_add_amount_msat(req->js, "maxfee_msat", feebudget);
+	json_add_u32(req->js, "final_cltv", payment->payment_info.final_cltv);
+	json_add_u32(req->js, "maxdelay", payment->payment_info.maxdelay);
+	json_array_start(req->js, "layers");
+	json_add_string(req->js, NULL, "auto.localchans");
+	json_add_string(req->js, NULL, "auto.sourcefree");
+	/* Global knowledge of the network comes here.
+	 * eg. liquidity estimation for public channels, biases on bad
+	 * channels/nodes. */
+	json_add_string(req->js, NULL, RENEPAY_LAYER);
+	/* Knowledge that is only relevant to this payment comes here.
+	 * eg. fake nodes/channels, private channel hints, biases on bad
+	 * channels for this particular routing problem. */
+	json_add_string(req->js, NULL, payment->payment_layer);
+	/* Constraints that are only relevant to the last command invocation
+	 * comes here.
+	 * eg. manual node/channel exclusions. */
+	json_add_string(req->js, NULL, payment->command_layer);
+	json_array_end(req->js);
+
+	return send_outreq(req);
+
+	// FIXME: remove from here below
+
 	enum jsonrpc_errcode errcode;
 	const char *err_msg = NULL;
 
@@ -749,7 +825,7 @@ static struct command_result *compute_routes_cb(struct payment *payment)
 	return payment_continue(payment);
 }
 
-REGISTER_PAYMENT_MODIFIER(compute_routes, compute_routes_cb);
+REGISTER_PAYMENT_MODIFIER(getroutes, getroutes_cb);
 
 /*****************************************************************************
  * send_routes
@@ -1258,7 +1334,7 @@ void *payment_virtual_program[] = {
 	    /*16*/ OP_CALL, &pendingsendpays_pay_mod,
 	    /*18*/ OP_CALL, &checktimeout_pay_mod,
 	    /*20*/ OP_CALL, &refreshgossmap_pay_mod,
-	    /*22*/ OP_CALL, &compute_routes_pay_mod,
+	    /*22*/ OP_CALL, &getroutes_pay_mod,
 	    /*24*/ OP_CALL, &send_routes_pay_mod,
 	    /*do*/
 		    /*26*/ OP_CALL, &sleep_pay_mod,

plugins/renepay/payment.h

@@ -73,6 +73,13 @@ struct payment {
 	struct plugin_timer *waitresult_timer;
 
 	struct routetracker *routetracker;
+
+	/* The name of the layer where we put information regarding this
+	 * payment. */
+	const char *payment_layer;
+	/* This layer contains constraints that are passed through the command
+	 * line, eg. manual exclusions. */
+	const char *command_layer;
 };
 
 static inline const struct sha256 payment_hash(const struct payment *p)

plugins/renepay/renepayconfig.h

@@ -2,6 +2,8 @@
 #define LIGHTNING_PLUGINS_RENEPAY_RENEPAYCONFIG_H
 #include "config.h"
 
+#define RENEPAY_LAYER "renepay"
+
 #define MAX_NUM_ATTEMPTS 10
 
 /* Knowledge is proportionally decreased with time up to TIMER_FORGET_SEC when