route: Change the type of the funding capacity to amount_sat

Keeping it in `amount_msat` made the comparisons easier, but it was
the wrong type for this.

common/json_stream.c

@@ -626,6 +626,14 @@ void json_add_amount_msat(struct json_stream *result,
 	json_add_u64(result, msatfieldname, msat.millisatoshis); /* Raw: low-level helper */
 }
 
+void json_add_amount_sat(struct json_stream *result,
+			  const char *satfieldname,
+			  struct amount_sat sat)
+{
+	assert(strends(satfieldname, "_sat") || streq(satfieldname, "sat"));
+	json_add_u64(result, satfieldname, sat.satoshis); /* Raw: low-level helper */
+}
+
 void json_add_amount_sat_msat(struct json_stream *result,
 			      const char *msatfieldname,
 			      struct amount_sat sat)

common/json_stream.h

@@ -5,10 +5,10 @@
 #define LIGHTNING_COMMON_JSON_STREAM_H
 #include "config.h"
 
-#include <bitcoin/short_channel_id.h>
 #define JSMN_STRICT 1
 # include <external/jsmn/jsmn.h>
 
+#include <bitcoin/short_channel_id.h>
 #include <ccan/short_types/short_types.h>
 #include <ccan/tal/tal.h>
 #include <ccan/time/time.h>
@@ -334,6 +334,11 @@ void json_add_amount_msat(struct json_stream *result,
 			  struct amount_msat msat)
 	NO_NULL_ARGS;
 
+void json_add_amount_sat(struct json_stream *result,
+			  const char *satfieldname,
+			  struct amount_sat sat)
+	NO_NULL_ARGS;
+
 /* Adds an 'msat' field */
 void json_add_amount_sat_msat(struct json_stream *result,
 			      const char *msatfieldname,

common/route.c

@@ -105,8 +105,7 @@ static bool dijkstra_to_hops(struct route_hop **hops,
 		return false;
 
 	gossmap_chan_get_capacity(gossmap, c, &total);
-	if (!amount_sat_to_msat(&((*hops[num_hops]).total_amount), total))
+	(*hops)[num_hops].capacity = total;
-		abort();
 	(*hops)[num_hops].amount = *amount;
 	(*hops)[num_hops].delay = *cltv;
 

common/route.h

@@ -18,7 +18,7 @@ struct gossmap_node;
  * @direction: 0 (dest node_id < src node_id), 1 (dest node_id > src).
  * @node_id: the node_id of the destination of this hop.
  * @amount: amount to send through this hop.
- * @total_amount: The amount the channel was funded with.
+ * @capacity: The amount the channel was funded with.
  * @delay: total cltv delay at this hop.
  */
 struct route_hop {
@@ -26,7 +26,7 @@ struct route_hop {
 	int direction;
 	struct node_id node_id;
 	struct amount_msat amount;
-	struct amount_msat total_amount;
+	struct amount_sat capacity;
 	u32 delay;
 };
 

plugins/channel_hint.c

@@ -9,8 +9,7 @@ void channel_hint_to_json(const char *name, const struct channel_hint *hint,
 	json_add_short_channel_id_dir(dest, "scid", hint->scid);
 	json_add_amount_msat(dest, "estimated_capacity_msat",
 			     hint->estimated_capacity);
-	json_add_amount_msat(dest, "capacity_msat",
+	json_add_amount_sat(dest, "capacity_sat", hint->capacity);
-			     hint->capacity);
 	json_add_bool(dest, "enabled", hint->enabled);
 	json_object_end(dest);
 }
@@ -37,8 +36,12 @@ bool channel_hint_update(const struct timeabs now, struct channel_hint *hint)
 	 * overall / refill_rate`.
 	 */
 	struct amount_msat refill;
+	struct amount_msat capacity;
+	if (!amount_sat_to_msat(&capacity, hint->capacity))
+		abort();
+
 	u64 seconds = now.ts.tv_sec - hint->timestamp;
-	if (!amount_msat_mul(&refill, hint->capacity, seconds))
+	if (!amount_msat_mul(&refill, capacity, seconds))
 		abort();
 
 	refill = amount_msat_div(refill, PAY_REFILL_TIME);
@@ -47,9 +50,8 @@ bool channel_hint_update(const struct timeabs now, struct channel_hint *hint)
 		abort();
 
 	/* Clamp the value to the `overall_capacity` */
-	if (amount_msat_greater(hint->estimated_capacity,
+	if (amount_msat_greater(hint->estimated_capacity, capacity))
-				hint->capacity))
+		hint->estimated_capacity = capacity;
-		hint->estimated_capacity = hint->capacity;
 
 	/* TODO This is rather coarse. We could map the disabled flag
 	to having 0msat capacity, and then relax from there. But it'd
@@ -65,8 +67,8 @@ bool channel_hint_update(const struct timeabs now, struct channel_hint *hint)
 	/* We report this hint as useless, if the hint does not
 	 * restrict the channel, i.e., if it is enabled and the
 	 * estimate is the same as the overall capacity. */
-	return !hint->enabled || amount_msat_greater(hint->capacity,
+	return !hint->enabled ||
-						     hint->estimated_capacity);
+	       amount_msat_greater(capacity, hint->estimated_capacity);
 }
 
 /**
@@ -90,7 +92,7 @@ struct channel_hint *channel_hint_from_json(const tal_t *ctx,
 			JSON_SCAN(json_to_u32, &hint->timestamp),
 			JSON_SCAN(json_to_short_channel_id_dir, &hint->scid),
 			JSON_SCAN(json_to_msat, &hint->estimated_capacity),
-			JSON_SCAN(json_to_msat, &hint->capacity),
+			JSON_SCAN(json_to_sat, &hint->capacity),
 			JSON_SCAN(json_to_bool, &hint->enabled));
 
 	if (ret != NULL)

plugins/channel_hint.h

@@ -40,10 +40,10 @@ struct channel_hint {
 	/* Non-null if we are one endpoint of this channel */
 	struct local_hint *local;
 
-	/* The total `amount_msat` that were used to fund the
+	/* The total `amount_sat` that were used to fund the
 	 * channel. This is always smaller gte the
-	 * estimated_capacity */
+	 * estimated_capacity (after normalization) */
-	struct amount_msat capacity;
+	struct amount_sat capacity;
 };
 
 /* A collection of channel_hint instances, allowing us to handle and

plugins/libplugin-pay.c

@@ -409,7 +409,7 @@ static void channel_hints_update(struct payment *p,
 				 const struct short_channel_id scid,
 				 int direction, bool enabled, bool local,
 				 const struct amount_msat *estimated_capacity,
-				 const struct amount_msat overall_capacity,
+				 const struct amount_sat overall_capacity,
 				 u16 *htlc_budget)
 {
 	struct payment *root = payment_root(p);
@@ -476,8 +476,9 @@ static void channel_hints_update(struct payment *p,
 		newhint.local = NULL;
 	if (estimated_capacity != NULL)
 		newhint.estimated_capacity = *estimated_capacity;
-	else
+	else if (!amount_sat_to_msat(&newhint.estimated_capacity,
-		newhint.estimated_capacity = overall_capacity;
+				     overall_capacity))
+		abort();
 
 	tal_arr_expand(&root->channel_hints, newhint);
 
@@ -505,7 +506,7 @@ static void payment_exclude_most_expensive(struct payment *p)
 		}
 	}
 	channel_hints_update(p, e->scid, e->direction, false, false, NULL,
-			     e->total_amount, NULL);
+			     e->capacity, NULL);
 }
 
 static void payment_exclude_longest_delay(struct payment *p)
@@ -521,7 +522,7 @@ static void payment_exclude_longest_delay(struct payment *p)
 		}
 	}
 	channel_hints_update(p, e->scid, e->direction, false, false, NULL,
-			     e->total_amount, NULL);
+			     e->capacity, NULL);
 }
 
 static struct amount_msat payment_route_fee(struct payment *p)
@@ -1467,7 +1468,7 @@ handle_final_failure(struct command *cmd,
 	case WIRE_TEMPORARY_NODE_FAILURE:
 	case WIRE_REQUIRED_NODE_FEATURE_MISSING:
 	case WIRE_INVALID_ONION_BLINDING:
- 	case WIRE_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS:
+	case WIRE_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS:
 	case WIRE_MPP_TIMEOUT:
 		goto error;
 	}
@@ -1519,9 +1520,9 @@ handle_intermediate_failure(struct command *cmd,
 	 *...
 	 *     - MUST return a `final_incorrect_htlc_amount` error.
 	 */
- 	case WIRE_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS:
+	case WIRE_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS:
- 	case WIRE_FINAL_INCORRECT_CLTV_EXPIRY:
+	case WIRE_FINAL_INCORRECT_CLTV_EXPIRY:
- 	case WIRE_FINAL_INCORRECT_HTLC_AMOUNT:
+	case WIRE_FINAL_INCORRECT_HTLC_AMOUNT:
 	/* FIXME: Document in BOLT that intermediates must not return this! */
 	case WIRE_MPP_TIMEOUT:
 		goto strange_error;
@@ -1532,7 +1533,7 @@ handle_intermediate_failure(struct command *cmd,
 	case WIRE_REQUIRED_CHANNEL_FEATURE_MISSING:
 		/* All of these result in the channel being marked as disabled. */
 		channel_hints_update(root, errchan->scid, errchan->direction,
-				     false, false, NULL, errchan->total_amount,
+				     false, false, NULL, errchan->capacity,
 				     NULL);
 		break;
 
@@ -1551,7 +1552,7 @@ handle_intermediate_failure(struct command *cmd,
 		 * remember the amount we tried as an estimate. */
 		channel_hints_update(root, errchan->scid, errchan->direction,
 				     true, false, &estimated,
-				     errchan->total_amount, NULL);
+				     errchan->capacity, NULL);
 		goto error;
 	}
 
@@ -1671,13 +1672,13 @@ static u8 *channel_update_from_onion_error(const tal_t *ctx,
 					   onion_message, &unused_msat,
 					   &channel_update) &&
 	    !fromwire_fee_insufficient(ctx,
-		    		       onion_message, &unused_msat,
+				       onion_message, &unused_msat,
 				       &channel_update) &&
 	    !fromwire_incorrect_cltv_expiry(ctx,
-		    			    onion_message, &unused32,
+					    onion_message, &unused32,
 					    &channel_update) &&
 	    !fromwire_expiry_too_soon(ctx,
-		    		      onion_message,
+				      onion_message,
 				      &channel_update))
 		/* No channel update. */
 		return NULL;
@@ -2631,6 +2632,7 @@ local_channel_hints_listpeerchannels(struct command *cmd, const char *buffer,
 				     const jsmntok_t *toks, struct payment *p)
 {
 	struct listpeers_channel **chans;
+	struct amount_sat capacity;
 
 	chans = json_to_listpeers_channels(tmpctx, buffer, toks);
 
@@ -2655,6 +2657,9 @@ local_channel_hints_listpeerchannels(struct command *cmd, const char *buffer,
 		else
 			htlc_budget = chans[i]->max_accepted_htlcs - chans[i]->num_htlcs;
 
+		if(!amount_msat_to_sat(&capacity, chans[i]->total_msat))
+			abort();
+
 		/* If we have both a scid and a local alias we want to
 		 * use the scid, and mark the alias as
 		 * unusable. Otherwise `getroute` might return the
@@ -2667,19 +2672,19 @@ local_channel_hints_listpeerchannels(struct command *cmd, const char *buffer,
 			channel_hints_update(
 			    p, *chans[i]->scid, chans[i]->direction, enabled,
 			    true, &chans[i]->spendable_msat,
-			    chans[i]->total_msat, &htlc_budget);
+			    capacity, &htlc_budget);
 			if (chans[i]->alias[LOCAL] != NULL)
 				channel_hints_update(p, *chans[i]->alias[LOCAL],
 						     chans[i]->direction,
 						     false /* not enabled */,
 						     true, &AMOUNT_MSAT(0),
-						     chans[i]->total_msat,
+						     capacity,
 						     &htlc_budget);
 		} else {
 			channel_hints_update(
 			    p, *chans[i]->alias[LOCAL], chans[i]->direction,
 			    enabled, true, &chans[i]->spendable_msat,
-			    chans[i]->total_msat, &htlc_budget);
+			    capacity, &htlc_budget);
 		}
 	}
 
@@ -3170,7 +3175,7 @@ static void routehint_step_cb(struct routehints_data *d, struct payment *p)
 			hop.amount = dest_amount;
 			hop.delay = route_cltv(d->final_cltv, routehint + i + 1,
 					       tal_count(routehint) - i - 1);
-			hop.total_amount = estimate;
+			hop.capacity = amount_msat_to_sat_round_down(estimate);
 
 			/* Should we get a failure inside the routehint we'll
 			 * need the direction so we can exclude it. Luckily
@@ -3539,7 +3544,7 @@ static void direct_pay_override(struct payment *p) {
 		p->route[0].scid = hint->scid.scid;
 		p->route[0].direction = hint->scid.dir;
 		p->route[0].node_id = *p->route_destination;
-		p->route[0].total_amount = hint->capacity;
+		p->route[0].capacity = hint->capacity;
 		paymod_log(p, LOG_DBG,
 			   "Found a direct channel (%s) with sufficient "
 			   "capacity, skipping route computation.",
@@ -3947,7 +3952,7 @@ static void route_exclusions_step_cb(struct route_exclusions_data *d,
 		struct route_exclusion *e = exclusions[i];
 
 		/* We don't need the details if we skip anyway. */
-		struct amount_msat total = AMOUNT_MSAT(0);
+		struct amount_sat total = AMOUNT_SAT(0);
 
 		if (e->type == EXCLUDE_CHANNEL) {
 			channel_hints_update(p, e->u.chan_id.scid,