channeld, openingd: take into account option_anchor_outputs for fees.

HTLC fees increase (larger weight), and the fee paid by the opener
has to include the anchor outputs (i.e. 660 sats).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

channeld/commit_tx.c

@@ -18,7 +18,8 @@ static bool trim(const struct htlc *htlc,
 		 enum side side)
 {
 	return htlc_is_trimmed(htlc_owner(htlc), htlc->amount,
-			       feerate_per_kw, dust_limit, side);
+			       feerate_per_kw, dust_limit, side,
+			       false /* FIXME-anchor */);
 }
 
 size_t commit_tx_num_untrimmed(const struct htlc **htlcs,
@@ -118,7 +119,8 @@ struct bitcoin_tx *commit_tx(const tal_t *ctx,
 	 * 2. Calculate the base [commitment transaction
 	 * fee](#fee-calculation).
 	 */
-	base_fee = commit_tx_base_fee(feerate_per_kw, untrimmed);
+	base_fee = commit_tx_base_fee(feerate_per_kw, untrimmed,
+				      false /* FIXME-anchor */);
 
 	SUPERVERBOSE("# base commitment transaction fee = %s\n",
 		     type_to_string(tmpctx, struct amount_sat, &base_fee));

channeld/full_channel.c

@@ -390,7 +390,8 @@ static struct amount_sat fee_for_htlcs(const struct channel *channel,
 	untrimmed = num_untrimmed_htlcs(side, dust_limit, feerate,
 					committed, adding, removing);
 
-	return commit_tx_base_fee(feerate, untrimmed);
+	return commit_tx_base_fee(feerate, untrimmed,
+				  false /* FIXME-anchor */);
 }
 
 /*
@@ -438,7 +439,8 @@ static bool local_opener_has_fee_headroom(const struct channel *channel,
 
 	/* Now, how much would it cost us if feerate increases 100% and we added
 	 * another HTLC? */
-	fee = commit_tx_base_fee(2 * feerate, untrimmed + 1);
+	fee = commit_tx_base_fee(2 * feerate, untrimmed + 1,
+				 false /* FIXME-anchor */);
 	if (amount_msat_greater_eq_sat(remainder, fee))
 		return true;
 
@@ -1034,7 +1036,8 @@ bool can_opener_afford_feerate(const struct channel *channel, u32 feerate_per_kw
 			- commit_tx_num_untrimmed(removing, feerate_per_kw, dust_limit,
 						  !channel->opener);
 
-	fee = commit_tx_base_fee(feerate_per_kw, untrimmed);
+	fee = commit_tx_base_fee(feerate_per_kw, untrimmed,
+				 false /* FIXME-anchor */);
 
 	/* BOLT #2:
 	 *

channeld/test/run-commit_tx.c

@@ -967,7 +967,8 @@ int main(int argc, const char *argv[])
 	 * its output cannot go negative! */
 	for (;;) {
 		struct amount_sat base_fee
-			= commit_tx_base_fee(feerate_per_kw, 0);
+			= commit_tx_base_fee(feerate_per_kw, 0,
+					     option_anchor_outputs);
 
 		if (amount_msat_greater_eq_sat(to_local, base_fee)) {
 			feerate_per_kw++;

common/htlc_trim.c

@@ -6,7 +6,8 @@ bool htlc_is_trimmed(enum side htlc_owner,
 		     struct amount_msat htlc_amount,
 		     u32 feerate_per_kw,
 		     struct amount_sat dust_limit,
-		     enum side side)
+		     enum side side,
+		     bool option_anchor_outputs)
 {
 	struct amount_sat htlc_fee, htlc_min;
 
@@ -21,7 +22,8 @@ bool htlc_is_trimmed(enum side htlc_owner,
 	 *      [Offered HTLC Outputs](#offered-htlc-outputs).
 	 */
 	if (htlc_owner == side)
-		htlc_fee = htlc_timeout_fee(feerate_per_kw);
+		htlc_fee = htlc_timeout_fee(feerate_per_kw,
+					    option_anchor_outputs);
 	/* BOLT #3:
 	 *
 	 *  - for every received HTLC:
@@ -32,7 +34,8 @@ bool htlc_is_trimmed(enum side htlc_owner,
 	 *      - MUST be generated as specified in
 	 */
 	else
-		htlc_fee = htlc_success_fee(feerate_per_kw);
+		htlc_fee = htlc_success_fee(feerate_per_kw,
+					    option_anchor_outputs);
 
 	/* If these overflow, it implies htlc must be less. */
 	if (!amount_sat_add(&htlc_min, dust_limit, htlc_fee))

common/htlc_trim.h

@@ -9,6 +9,7 @@ bool htlc_is_trimmed(enum side htlc_owner,
 		     struct amount_msat htlc_amount,
 		     u32 feerate_per_kw,
 		     struct amount_sat dust_limit,
-		     enum side side);
+		     enum side side,
+		     bool option_anchor_outputs);
 
 #endif /* LIGHTNING_COMMON_HTLC_TRIM_H */

common/htlc_tx.c

@@ -93,7 +93,7 @@ struct bitcoin_tx *htlc_success_tx(const tal_t *ctx,
 		       to_self_delay,
 		       &keyset->self_revocation_key,
 		       &keyset->self_delayed_payment_key,
-		       htlc_success_fee(feerate_per_kw),
+		       htlc_success_fee(feerate_per_kw,	false /* FIXME-anchor */),
 		       0,
 		       option_anchor_outputs);
 }
@@ -145,7 +145,7 @@ struct bitcoin_tx *htlc_timeout_tx(const tal_t *ctx,
 		       commit_wscript, htlc_msatoshi, to_self_delay,
 		       &keyset->self_revocation_key,
 		       &keyset->self_delayed_payment_key,
-		       htlc_timeout_fee(feerate_per_kw),
+		       htlc_timeout_fee(feerate_per_kw,	false /* FIXME-anchor */),
 		       cltv_expiry,
 		       option_anchor_outputs);
 }

common/htlc_tx.h

@@ -39,28 +39,40 @@ static inline size_t elements_add_overhead(size_t weight, size_t incount,
 	return weight;
 }
 
-static inline struct amount_sat htlc_timeout_fee(u32 feerate_per_kw)
+static inline struct amount_sat htlc_timeout_fee(u32 feerate_per_kw,
+						 bool option_anchor_outputs)
 {
-	/* BOLT #3:
+	/* BOLT-a12da24dd0102c170365124782b46d9710950ac1 #3:
 	 *
 	 * The fee for an HTLC-timeout transaction:
-	 *  - MUST BE calculated to match:
+	 * - MUST BE calculated to match:
-	 *    1. Multiply `feerate_per_kw` by 663 and divide by 1000 (rounding
+	 *   1. Multiply `feerate_per_kw` by 663 (666 if `option_anchor_outputs`
-	 *       down).
+	 *      applies) and divide by 1000 (rounding down).
 	 */
-	return amount_tx_fee(elements_add_overhead(663, 1, 1), feerate_per_kw);
+	u32 base;
+	if (option_anchor_outputs)
+		base = 666;
+	else
+		base = 663;
+	return amount_tx_fee(elements_add_overhead(base, 1, 1), feerate_per_kw);
 }
 
-static inline struct amount_sat htlc_success_fee(u32 feerate_per_kw)
+static inline struct amount_sat htlc_success_fee(u32 feerate_per_kw,
+						 bool option_anchor_outputs)
 {
-	/* BOLT #3:
+	/* BOLT-a12da24dd0102c170365124782b46d9710950ac1 #3:
 	 *
 	 * The fee for an HTLC-success transaction:
-	 *   - MUST BE calculated to match:
+	 * - MUST BE calculated to match:
-	 *     1. Multiply `feerate_per_kw` by 703 and divide by 1000 (rounding
+	 *   1. Multiply `feerate_per_kw` by 703 (706 if `option_anchor_outputs`
-	 *     down).
+	 *      applies) and divide by 1000 (rounding down).
 	 */
-	return amount_tx_fee(elements_add_overhead(703, 1, 1), feerate_per_kw);
+	u32 base;
+	if (option_anchor_outputs)
+		base = 706;
+	else
+		base = 703;
+	return amount_tx_fee(elements_add_overhead(base, 1, 1), feerate_per_kw);
 }
 
 /* Create HTLC-success tx to spend a received HTLC commitment tx

common/initial_channel.c

@@ -111,6 +111,7 @@ struct bitcoin_tx *initial_channel_tx(const tal_t *ctx,
 				    0 ^ channel->commitment_number_obscurer,
 				    direct_outputs,
 				    side,
+				    false /* FIXME-anchor */,
 				    err_reason);
 
 	if (init_tx) {

common/initial_commit_tx.c

@@ -74,6 +74,7 @@ struct bitcoin_tx *initial_commit_tx(const tal_t *ctx,
 				     u64 obscured_commitment_number,
 				     struct wally_tx_output *direct_outputs[NUM_SIDES],
 				     enum side side,
+				     bool option_anchor_outputs,
 				     char** err_reason)
 {
 	struct amount_sat base_fee;
@@ -101,7 +102,8 @@ struct bitcoin_tx *initial_commit_tx(const tal_t *ctx,
 	 * 2. Calculate the base [commitment transaction
 	 * fee](#fee-calculation).
 	 */
-	base_fee = commit_tx_base_fee(feerate_per_kw, untrimmed);
+	base_fee = commit_tx_base_fee(feerate_per_kw, untrimmed,
+				      option_anchor_outputs);
 
 	/* BOLT #3:
 	 *

common/initial_commit_tx.h

@@ -23,17 +23,21 @@ u64 commit_number_obscurer(const struct pubkey *opener_payment_basepoint,
 
 /* Helper to calculate the base fee if we have this many htlc outputs */
 static inline struct amount_sat commit_tx_base_fee(u32 feerate_per_kw,
-						   size_t num_untrimmed_htlcs)
+						   size_t num_untrimmed_htlcs,
+						   bool option_anchor_outputs)
 {
 	u64 weight;
 
-	/* BOLT #3:
+	/* BOLT-a12da24dd0102c170365124782b46d9710950ac1 #3:
 	 *
 	 * The base fee for a commitment transaction:
 	 *  - MUST be calculated to match:
-	 *    1. Start with `weight` = 724.
+	 *    1. Start with `weight` = 724 (1124 if `option_anchor_outputs` applies).
 	 */
-	weight = 724;
+	if (option_anchor_outputs)
+		weight = 1124;
+	else
+		weight = 724;
 
 	/* BOLT #3:
 	 *
@@ -87,6 +91,7 @@ static inline struct amount_sat commit_tx_base_fee(u32 feerate_per_kw,
  * @obscured_commitment_number: number to encode in commitment transaction
  * @direct_outputs: If non-NULL, fill with pointers to the direct (non-HTLC) outputs (or NULL if none).
  * @side: side to generate commitment transaction for.
+ * @option_anchor_outputs: does option_anchor_outputs apply to this channel?
  * @err_reason: When NULL is returned, this will point to a human readable reason.
  *
  * We need to be able to generate the remote side's tx to create signatures,
@@ -109,6 +114,7 @@ struct bitcoin_tx *initial_commit_tx(const tal_t *ctx,
 				     u64 obscured_commitment_number,
 				     struct wally_tx_output *direct_outputs[NUM_SIDES],
 				     enum side side,
+				     bool option_anchor_outputs,
 				     char** err_reason);
 
 /* try_subtract_fee - take away this fee from the opener (and return true), or all if insufficient (and return false). */

devtools/mkclose.c

@@ -70,6 +70,7 @@ int main(int argc, char *argv[])
 	const u8 *funding_wscript;
 	const struct chainparams *chainparams = chainparams_for_network("bitcoin");
 	const struct amount_sat dust_limit = AMOUNT_SAT(546);
+	bool option_anchor_outputs = false;
 
 	setup_locale();
 
@@ -117,7 +118,8 @@ int main(int argc, char *argv[])
 		errx(1, "Parsing remote-close-pubkey");
 	argnum++;
 
-	fee = commit_tx_base_fee(feerate_per_kw, 0);
+	fee = commit_tx_base_fee(feerate_per_kw, 0,
+				 option_anchor_outputs);
 	if (!amount_msat_sub_sat(&local_msat, local_msat, fee))
 		errx(1, "Can't afford fee %s",
 		     type_to_string(NULL, struct amount_sat, &fee));

lightningd/chaintopology.c

@@ -16,6 +16,8 @@
 #include <ccan/tal/str/str.h>
 #include <common/coin_mvt.h>
 #include <common/configdir.h>
+#include <common/features.h>
+#include <common/htlc_tx.h>
 #include <common/json_command.h>
 #include <common/jsonrpc_errors.h>
 #include <common/memleak.h>
@@ -526,6 +528,11 @@ static struct command_result *json_feerates(struct command *cmd,
 	json_object_end(response);
 
 	if (!missing) {
+		/* It actually is negotiated per-channel... */
+		bool anchor_outputs
+			= feature_offered(cmd->ld->our_features->bits[INIT_FEATURE],
+					  OPT_ANCHOR_OUTPUTS);
+
 		json_object_start(response, "onchain_fee_estimates");
 		/* eg 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 == weight 702 */
 		json_add_num(response, "opening_channel_satoshis",
@@ -536,20 +543,15 @@ static struct command_result *json_feerates(struct command *cmd,
 		/* eg. 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 == weight 598 */
 		json_add_u64(response, "unilateral_close_satoshis",
 			     unilateral_feerate(cmd->ld->topology) * 598 / 1000);
-		/* BOLT #3:
+
-		 *
+		/* This really depends on whether we *negotiated*
-		 * The *expected weight* of an HTLC transaction is calculated as follows:
+		 * option_anchor_outputs for a particular channel! */
-		 * ...
-		 * results in weights of:
-		 *
-		 *	663 (HTLC-timeout)
-		 *	703 (HTLC-success)
-		 *
-		 */
 		json_add_u64(response, "htlc_timeout_satoshis",
-			     htlc_resolution_feerate(cmd->ld->topology) * 663 / 1000);
+			     htlc_timeout_fee(htlc_resolution_feerate(cmd->ld->topology),
+					      anchor_outputs).satoshis /* Raw: estimate */);
 		json_add_u64(response, "htlc_success_satoshis",
-			     htlc_resolution_feerate(cmd->ld->topology) * 703 / 1000);
+			     htlc_success_fee(htlc_resolution_feerate(cmd->ld->topology),
+					      anchor_outputs).satoshis /* Raw: estimate */);
 		json_object_end(response);
 	}
 

lightningd/closing_control.c

@@ -218,10 +218,12 @@ void peer_start_closingd(struct channel *channel,
 	 */
 	final_commit_feerate = get_feerate(channel->channel_info.fee_states,
 					   channel->opener, LOCAL);
-	feelimit = commit_tx_base_fee(final_commit_feerate, 0);
+	feelimit = commit_tx_base_fee(final_commit_feerate, 0,
+				      false /* FIXME-anchor */);
 
 	/* Pick some value above slow feerate (or min possible if unknown) */
-	minfee = commit_tx_base_fee(feerate_min(ld, NULL), 0);
+	minfee = commit_tx_base_fee(feerate_min(ld, NULL), 0,
+				    false /* FIXME-anchor */);
 
 	/* If we can't determine feerate, start at half unilateral feerate. */
 	feerate = mutual_close_feerate(ld->topology);
@@ -230,7 +232,8 @@ void peer_start_closingd(struct channel *channel,
 		if (feerate < feerate_floor())
 			feerate = feerate_floor();
 	}
-	startfee = commit_tx_base_fee(feerate, 0);
+	startfee = commit_tx_base_fee(feerate, 0,
+				      false /* FIXME-anchor */);
 
 	if (amount_sat_greater(startfee, feelimit))
 		startfee = feelimit;

lightningd/peer_control.c

@@ -471,7 +471,8 @@ static void json_add_htlcs(struct lightningd *ld,
 		json_add_string(response, "state",
 				htlc_state_name(hin->hstate));
 		if (htlc_is_trimmed(REMOTE, hin->msat, local_feerate,
-				    channel->our_config.dust_limit, LOCAL))
+				    channel->our_config.dust_limit, LOCAL,
+				    false /* FIXME-anchor */))
 			json_add_bool(response, "local_trimmed", true);
 		json_object_end(response);
 	}
@@ -492,7 +493,8 @@ static void json_add_htlcs(struct lightningd *ld,
 		json_add_string(response, "state",
 				htlc_state_name(hout->hstate));
 		if (htlc_is_trimmed(LOCAL, hout->msat, local_feerate,
-				    channel->our_config.dust_limit, LOCAL))
+				    channel->our_config.dust_limit, LOCAL,
+				    false /* FIXME-anchor */))
 			json_add_bool(response, "local_trimmed", true);
 		json_object_end(response);
 	}
@@ -532,7 +534,8 @@ static struct amount_sat commit_txfee(const struct channel *channel,
 		dust_limit = channel->channel_info.their_config.dust_limit;
 
 	/* Assume we tried to add "amount" */
-	if (!htlc_is_trimmed(side, amount, feerate, dust_limit, side))
+	if (!htlc_is_trimmed(side, amount, feerate, dust_limit, side,
+			     false /* FIXME-anchor */))
 		num_untrimmed_htlcs++;
 
 	for (hin = htlc_in_map_first(&ld->htlcs_in, &ini);
@@ -541,7 +544,8 @@ static struct amount_sat commit_txfee(const struct channel *channel,
 		if (hin->key.channel != channel)
 			continue;
 		if (!htlc_is_trimmed(!side, hin->msat, feerate, dust_limit,
-				     side))
+				     side,
+				     false /* FIXME-anchor */))
 			num_untrimmed_htlcs++;
 	}
 	for (hout = htlc_out_map_first(&ld->htlcs_out, &outi);
@@ -550,7 +554,8 @@ static struct amount_sat commit_txfee(const struct channel *channel,
 		if (hout->key.channel != channel)
 			continue;
 		if (!htlc_is_trimmed(side, hout->msat, feerate, dust_limit,
-				     side))
+				     side,
+				     false /* FIXME-anchor */))
 			num_untrimmed_htlcs++;
 	}
 
@@ -567,7 +572,8 @@ static struct amount_sat commit_txfee(const struct channel *channel,
 	 *       ("fee spike buffer"). A buffer of 2*feerate_per_kw is
 	 *       recommended to ensure predictability.
 	 */
-	return commit_tx_base_fee(2 * feerate, num_untrimmed_htlcs + 1);
+	return commit_tx_base_fee(2 * feerate, num_untrimmed_htlcs + 1,
+				  false /* FIXME-anchor */);
 }
 
 static void subtract_offered_htlcs(const struct channel *channel,

lightningd/test/run-invoice-select-inchan.c

@@ -147,7 +147,8 @@ bool htlc_is_trimmed(enum side htlc_owner UNNEEDED,
 		     struct amount_msat htlc_amount UNNEEDED,
 		     u32 feerate_per_kw UNNEEDED,
 		     struct amount_sat dust_limit UNNEEDED,
-		     enum side side UNNEEDED)
+		     enum side side UNNEEDED,
+		     bool option_anchor_outputs UNNEEDED)
 { fprintf(stderr, "htlc_is_trimmed called!\n"); abort(); }
 /* Generated stub for htlc_set_fail */
 void htlc_set_fail(struct htlc_set *set UNNEEDED, const u8 *failmsg TAKES UNNEEDED)

onchaind/onchaind.c

@@ -451,19 +451,25 @@ static bool set_htlc_timeout_fee(struct bitcoin_tx *tx,
 {
 	static struct amount_sat amount, fee = AMOUNT_SAT_INIT(UINT64_MAX);
 	struct amount_asset asset = bitcoin_tx_output_get_amount(tx, 0);
-	size_t weight = elements_add_overhead(663, tx->wtx->num_inputs,
+	size_t weight;
-					      tx->wtx->num_outputs);
+
+	/* BOLT-a12da24dd0102c170365124782b46d9710950ac1 #3:
+	 *
+	 * The fee for an HTLC-timeout transaction:
+	 *  - MUST BE calculated to match:
+	 *    1. Multiply `feerate_per_kw` by 663 (666 if `option_anchor_outputs`
+	 *       applies) and divide by 1000 (rounding down).
+	 */
+	if (option_anchor_outputs)
+		weight = 666;
+	else
+		weight = 663;
+	weight = elements_add_overhead(weight, tx->wtx->num_inputs,
+				       tx->wtx->num_outputs);
 
 	assert(amount_asset_is_main(&asset));
 	amount = amount_asset_to_sat(&asset);
 
-	/* BOLT #3:
-	 *
-	 * The fee for an HTLC-timeout transaction:
-	 *  - MUST BE calculated to match:
-	 *    1. Multiply `feerate_per_kw` by 663 and divide by 1000 (rounding
-	 *    down).
-	 */
 	if (amount_sat_eq(fee, AMOUNT_SAT(UINT64_MAX))) {
 		struct amount_sat grindfee;
 		if (grind_htlc_tx_fee(&grindfee, tx, remotesig, wscript, weight)) {
@@ -492,15 +498,22 @@ static void set_htlc_success_fee(struct bitcoin_tx *tx,
 {
 	static struct amount_sat amt, fee = AMOUNT_SAT_INIT(UINT64_MAX);
 	struct amount_asset asset;
-	size_t weight = elements_add_overhead(703, tx->wtx->num_inputs,
+	size_t weight;
-					      tx->wtx->num_outputs);
+
-	/* BOLT #3:
+	/* BOLT-a12da24dd0102c170365124782b46d9710950ac1 #3:
 	 *
 	 * The fee for an HTLC-success transaction:
-	 *  - MUST BE calculated to match:
+	 * - MUST BE calculated to match:
-	 *    1. Multiply `feerate_per_kw` by 703 and divide by 1000
+	 *   1. Multiply `feerate_per_kw` by 703 (706 if `option_anchor_outputs`
-	 *    (rounding down).
+	 *      applies) and divide by 1000 (rounding down).
 	 */
+	if (option_anchor_outputs)
+		weight = 706;
+	else
+		weight = 703;
+
+	weight = elements_add_overhead(weight, tx->wtx->num_inputs,
+				       tx->wtx->num_outputs);
 	if (amount_sat_eq(fee, AMOUNT_SAT(UINT64_MAX))) {
 		if (!grind_htlc_tx_fee(&fee, tx, remotesig, wscript, weight))
 			status_failed(STATUS_FAIL_INTERNAL_ERROR,

wallet/test/run-wallet.c

@@ -152,7 +152,8 @@ bool htlc_is_trimmed(enum side htlc_owner UNNEEDED,
 		     struct amount_msat htlc_amount UNNEEDED,
 		     u32 feerate_per_kw UNNEEDED,
 		     struct amount_sat dust_limit UNNEEDED,
-		     enum side side UNNEEDED)
+		     enum side side UNNEEDED,
+		     bool option_anchor_outputs UNNEEDED)
 { fprintf(stderr, "htlc_is_trimmed called!\n"); abort(); }
 /* Generated stub for htlc_set_add */
 void htlc_set_add(struct lightningd *ld UNNEEDED,