config: don't ignore the --commit-fee option.

We did not take the value set by the user of --commit-fee : this removes
the unused option from lightningd and instead registers it in bcli,
where we set the actual feerate of commitment transactions. This also
corrects the documentation.

Changelog-Fixed: config: we now take the --commit-fee parameter into account.
Signed-off-by: Antoine Poinsot <darosior@protonmail.com>

doc/lightningd-config.5

@@ -332,8 +332,8 @@ opens a channel before the channel is usable\.
 
 
  \fBcommit-fee\fR=\fIPERCENT\fR
-The percentage of \fIestimatesmartfee 2\fR to use for the bitcoin
-transaction which funds a channel: can be greater than 100\.
+The percentage of \fIestimatesmartfee 2/CONSERVATIVE\fR to use for the commitment
+transactions: default is 100\.
 
 
  \fBcommit-fee-min\fR=\fIPERCENT\fR

doc/lightningd-config.5.md

@@ -270,8 +270,8 @@ Confirmations required for the funding transaction when the other side
 opens a channel before the channel is usable.
 
  **commit-fee**=*PERCENT*
-The percentage of *estimatesmartfee 2* to use for the bitcoin
-transaction which funds a channel: can be greater than 100.
+The percentage of *estimatesmartfee 2/CONSERVATIVE* to use for the commitment
+transactions: default is 100.
 
  **commit-fee-min**=*PERCENT*
  **commit-fee-max**=*PERCENT*

lightningd/lightningd.h

@@ -32,9 +32,6 @@ struct config {
 	/* Minimum percent of fee rate we'll accept. */
 	u32 commitment_fee_min_percent;
 
-	/* Percent of fee rate we'll use. */
-	u32 commitment_fee_percent;
-
 	/* Minimum CLTV to subtract from incoming HTLCs to outgoing */
 	u32 cltv_expiry_delta;
 

lightningd/options.c

@@ -570,9 +570,6 @@ static const struct config testnet_config = {
 	.commitment_fee_min_percent = 0,
 	.commitment_fee_max_percent = 0,
 
-	/* We offer to pay 5 times 2-block fee */
-	.commitment_fee_percent = 500,
-
 	/* Testnet blockspace is free. */
 	.max_concurrent_htlcs = 483,
 
@@ -618,9 +615,6 @@ static const struct config mainnet_config = {
 	.commitment_fee_min_percent = 200,
 	.commitment_fee_max_percent = 2000,
 
-	/* We offer to pay 5 times 2-block fee */
-	.commitment_fee_percent = 500,
-
 	/* While up to 483 htlcs are possible we do 30 by default (as eclair does) to save blockspace */
 	.max_concurrent_htlcs = 30,
 
@@ -819,9 +813,6 @@ static void register_opts(struct lightningd *ld)
 	opt_register_arg("--commit-fee-max=<percent>", opt_set_u32, opt_show_u32,
 			 &ld->config.commitment_fee_max_percent,
 			 "Maximum percentage of fee to accept for commitment (0 for unlimited)");
-	opt_register_arg("--commit-fee=<percent>", opt_set_u32, opt_show_u32,
-			 &ld->config.commitment_fee_percent,
-			 "Percentage of fee to request for their commitment");
 	opt_register_arg("--cltv-delta", opt_set_u32, opt_show_u32,
 			 &ld->config.cltv_expiry_delta,
 			 "Number of blocks for cltv_expiry_delta");

plugins/bcli.c

@@ -63,6 +63,9 @@ struct bitcoind {
 	/* The factor to time the urgent feerate by to get the maximum
 	 * acceptable feerate. */
 	u32 max_fee_multiplier;
+
+	/* Percent of CONSERVATIVE/2 feerate we'll use for commitment txs. */
+	u64 commit_fee_percent;
 };
 
 static struct bitcoind *bitcoind;
@@ -947,6 +950,7 @@ int main(int argc, char *argv[])
 	bitcoind->rpcconnect = NULL;
 	bitcoind->rpcport = NULL;
 	bitcoind->max_fee_multiplier = 10;
+	bitcoind->commit_fee_percent = 100;
 
 	plugin_main(argv, init, PLUGIN_STATIC, NULL, commands, ARRAY_SIZE(commands),
 		    NULL, 0, NULL, 0,
@@ -979,6 +983,10 @@ int main(int argc, char *argv[])
 				  "how long to keep retrying to contact bitcoind"
 				  " before fatally exiting",
 				  u64_option, &bitcoind->retry_timeout),
+		    plugin_option("commit-fee",
+				  "string",
+				  "Percentage of fee to request for their commitment",
+				  u64_option, &bitcoind->commit_fee_percent),
 #if DEVELOPER
 		    plugin_option("dev-max-fee-multiplier",
 				  "string",

wallet/test/test_utils.c

@@ -10,7 +10,6 @@ const struct config test_config = {
 	.anchor_confirms = 1,
 	.commitment_fee_min_percent = 0,
 	.commitment_fee_max_percent = 0,
-	.commitment_fee_percent = 500,
 	.cltv_expiry_delta = 6,
 	.cltv_final = 10,
 	.commit_time_ms = 10,