json: add cmd setchannelfee and wire to channeld

* adds the channeld_specific_feerates wire message 1029
* adds a json command handler
* adds u32 access methods for amount_msat

channeld/channel_wire.csv

@@ -178,3 +178,7 @@ channel_dev_memleak_reply,,leak,bool
 channel_fail_fallen_behind,1028
 channel_fail_fallen_behind,,remote_per_commitment_point,struct pubkey
 
+# Handle a channel specific feerate base ppm configuration
+channel_specific_feerates,1029
+channel_specific_feerates,,feerate_base,u32
+channel_specific_feerates,,feerate_ppm,u32

channeld/channeld.c

@@ -2528,6 +2528,22 @@ static void handle_feerates(struct peer *peer, const u8 *inmsg)
 	}
 }
 
+static void handle_specific_feerates(struct peer *peer, const u8 *inmsg)
+{
+	u32 base_old = peer->fee_base;
+	u32 per_satoshi_old = peer->fee_per_satoshi;
+
+	if (!fromwire_channel_specific_feerates(inmsg,
+				       &peer->fee_base,
+				       &peer->fee_per_satoshi))
+		master_badmsg(WIRE_CHANNEL_SPECIFIC_FEERATES, inmsg);
+
+	/* only send channel updates if values actually changed */
+	if (peer->fee_base != base_old || peer->fee_per_satoshi != per_satoshi_old)
+		send_channel_update(peer, 0);
+}
+
+
 static void handle_preimage(struct peer *peer, const u8 *inmsg)
 {
 	struct fulfilled_htlc fulfilled_htlc;
@@ -2648,6 +2664,9 @@ static void req_in(struct peer *peer, const u8 *msg)
 	case WIRE_CHANNEL_FAIL_HTLC:
 		handle_fail(peer, msg);
 		return;
+	case WIRE_CHANNEL_SPECIFIC_FEERATES:
+		handle_specific_feerates(peer, msg);
+		return;
 	case WIRE_CHANNEL_SEND_SHUTDOWN:
 		handle_shutdown_cmd(peer, msg);
 		return;

common/amount.c

@@ -362,6 +362,21 @@ bool amount_msat_less_eq_sat(struct amount_msat msat, struct amount_sat sat)
 	return msat.millisatoshis <= msat_from_sat.millisatoshis;
 }
 
+bool amount_msat_overflow_u32(struct amount_msat msat)
+{
+	return amount_msat_greater_eq(msat, AMOUNT_MSAT(0x100000000));
+}
+
+u32 amount_msat_to_u32(struct amount_msat msat)
+{
+	return (u32)msat.millisatoshis;
+}
+
+void amount_msat_from_u32(struct amount_msat *msat, u32 value)
+{
+	msat->millisatoshis = (u64)value;
+}
+
 bool amount_msat_fee(struct amount_msat *fee,
 		     struct amount_msat amt,
 		     u32 fee_base_msat,

common/amount.h

@@ -98,6 +98,15 @@ bool amount_msat_less_sat(struct amount_msat msat, struct amount_sat sat);
 /* Is msat <= sat? */
 bool amount_msat_less_eq_sat(struct amount_msat msat, struct amount_sat sat);
 
+/* Does value overflow u32 bit */
+bool amount_msat_overflow_u32(struct amount_msat msat);
+
+/* Return unchecked u32 value */
+u32 amount_msat_to_u32(struct amount_msat msat);
+
+/* Set by u32 value */
+void amount_msat_from_u32(struct amount_msat *msat, u32 value);
+
 /* Common operation: what is the HTLC fee for given feerate?  Can overflow! */
 WARN_UNUSED_RESULT bool amount_msat_fee(struct amount_msat *fee,
 					struct amount_msat amt,

lightningd/channel_control.c

@@ -232,6 +232,7 @@ static unsigned channel_msg(struct subd *sd, const u8 *msg, const int *fds)
 	case WIRE_CHANNEL_SEND_SHUTDOWN:
 	case WIRE_CHANNEL_DEV_REENABLE_COMMIT:
 	case WIRE_CHANNEL_FEERATES:
+	case WIRE_CHANNEL_SPECIFIC_FEERATES:
 	case WIRE_CHANNEL_DEV_MEMLEAK:
 	/* Replies go to requests. */
 	case WIRE_CHANNEL_OFFER_HTLC_REPLY:

lightningd/peer_control.c

@@ -1034,7 +1034,7 @@ AUTODATA(json_command, &listpeers_command);
 static struct command_result *
 command_find_channel(struct command *cmd,
 		     const char *buffer, const jsmntok_t *tok,
-		     struct channel **channel, struct peer **peer_out)
+		     struct channel **channel)
 {
 	struct lightningd *ld = cmd->ld;
 	struct channel_id cid;
@@ -1050,11 +1050,9 @@ command_find_channel(struct command *cmd,
 			derive_channel_id(&channel_cid,
 					  &(*channel)->funding_txid,
 					  (*channel)->funding_outnum);
-			if (channel_id_eq(&channel_cid, &cid)) {
-				if (peer_out) *peer_out = peer;
+			if (channel_id_eq(&channel_cid, &cid))
 				return NULL;
 		}
-		}
 		return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
 				    "Channel ID not found: '%.*s'",
 				    tok->end - tok->start,
@@ -1066,11 +1064,9 @@ command_find_channel(struct command *cmd,
 			if (!*channel)
 				continue;
 			if ((*channel)->scid
-			    && (*channel)->scid->u64 == scid.u64) {
-				if (peer_out) *peer_out = peer;
+			    && (*channel)->scid->u64 == scid.u64)
 				return NULL;
 		}
-		}
 		return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
 				    "Short channel ID not found: '%.*s'",
 				    tok->end - tok->start,
@@ -1108,7 +1104,7 @@ static struct command_result *json_close(struct command *cmd,
 		channel = peer_active_channel(peer);
 	else {
 		struct command_result *res;
-		res = command_find_channel(cmd, buffer, idtok, &channel, NULL);
+		res = command_find_channel(cmd, buffer, idtok, &channel);
 		if (res)
 			return res;
 	}
@@ -1343,6 +1339,104 @@ static const struct json_command getinfo_command = {
 };
 AUTODATA(json_command, &getinfo_command);
 
+
+static struct command_result *json_setchannelfee(struct command *cmd,
+					 const char *buffer,
+					 const jsmntok_t *obj UNNEEDED,
+					 const jsmntok_t *params)
+{
+	struct json_stream *response;
+	const jsmntok_t *idtok;
+	struct peer *peer;
+	struct channel *channel;
+	struct channel_id cid;
+	struct command_result *res;
+	struct amount_msat *base, base_default;
+	u32 *ppm, ppm_default;
+
+	/* Use daemon config values base/ppm as default */
+	amount_msat_from_u32(&base_default, cmd->ld->config.fee_base);
+	ppm_default = cmd->ld->config.fee_per_satoshi;
+
+	/* Parse the JSON command */
+	if (!param(cmd, buffer, params,
+			p_req("id", param_tok, &idtok),
+			p_opt_def("base", param_msat, &base, base_default),
+			p_opt_def("ppm", param_number, &ppm, ppm_default),
+			NULL))
+		return command_param_failed();
+
+	/* Check base for u32 overflow */
+	if (amount_msat_overflow_u32(*base))
+		return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+				"Value 'base' exceeds u32 max");
+
+	/* Find the channel */
+	peer = peer_from_json(cmd->ld, buffer, idtok);
+	if (peer) {
+		channel = peer_active_channel(peer);
+		if (!channel)
+			return command_fail(cmd, LIGHTNINGD,
+					"Could not find active channel of peer with that id");
+	} else {
+		res = command_find_channel(cmd, buffer, idtok, &channel);
+		if (res)
+			return res;
+		/* check channel is found and in valid state */
+		if (!channel)
+			return command_fail(cmd, LIGHTNINGD,
+					"Could not find channel with that id");
+		peer = channel->peer;
+	}
+
+	if (channel->state != CHANNELD_NORMAL &&
+		channel->state != CHANNELD_AWAITING_LOCKIN)
+		return command_fail(cmd, LIGHTNINGD,
+				"Channel is in state %s", channel_state_name(channel));
+
+	/* set, notify and save new values */
+	channel->feerate_base = amount_msat_to_u32(*base);
+	channel->feerate_ppm = *ppm;
+
+	/* tell channeld to make a send_channel_update */
+	if (channel->owner && streq(channel->owner->name, "lightning_channeld"))
+		subd_send_msg(channel->owner,
+				take(towire_channel_specific_feerates(channel,
+						amount_msat_to_u32(*base), *ppm)));
+
+	/* save values to database */
+	wallet_channel_save(cmd->ld->wallet, channel);
+
+	/* get channel id */
+	derive_channel_id(&cid, &channel->funding_txid, channel->funding_outnum);
+
+	/* write response */
+	response = json_stream_success(cmd);
+	json_object_start(response, NULL);
+	json_add_num(response, "base", amount_msat_to_u32(*base));
+	json_add_num(response, "ppm", *ppm);
+	json_add_pubkey(response, "peer_id", &peer->id);
+	json_add_string(response, "channel_id",
+			type_to_string(tmpctx, struct channel_id, &cid));
+	if (channel->scid)
+		json_add_short_channel_id(response, "short_channel_id", channel->scid);
+	json_object_end(response);
+	return command_success(cmd, response);
+}
+
+static const struct json_command setchannelfee_command = {
+	"setchannelfee",
+	json_setchannelfee,
+	"Sets specific routing fees for channel with {id} "
+	"(either peer ID, channel ID or short channel ID). "
+	"The routing fees are defined by a fixed {base} (msat) "
+	"and a {ppm} value (proportional per millionth)."
+	"To disable channel specific fees and restore global values, "
+	"just leave out the optional {base} and {ppm} values. "
+	"{base} can also be supplied in other units, i.e. '1sat'."
+};
+AUTODATA(json_command, &setchannelfee_command);
+
 #if DEVELOPER
 static struct command_result *json_sign_last_tx(struct command *cmd,
 						const char *buffer,

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

@@ -131,7 +131,7 @@ void json_add_amount_msat(struct json_stream *result UNNEEDED,
 void json_add_amount_sat(struct json_stream *result UNNEEDED,
 			 struct amount_sat sat UNNEEDED,
 			 const char *rawfieldname UNNEEDED,
-			 const char *satfieldname)
+			 const char *msatfieldname)
 
 { fprintf(stderr, "json_add_amount_sat called!\n"); abort(); }
 /* Generated stub for json_add_bool */
@@ -311,6 +311,11 @@ struct command_result *param_loglevel(struct command *cmd UNNEEDED,
 				      const jsmntok_t *tok UNNEEDED,
 				      enum log_level **level UNNEEDED)
 { fprintf(stderr, "param_loglevel called!\n"); abort(); }
+/* Generated stub for param_msat */
+struct command_result *param_msat(struct command *cmd UNNEEDED, const char *name UNNEEDED,
+				  const char *buffer UNNEEDED, const jsmntok_t *tok UNNEEDED,
+				  struct amount_msat **msat UNNEEDED)
+{ fprintf(stderr, "param_msat called!\n"); abort(); }
 /* Generated stub for param_number */
 struct command_result *param_number(struct command *cmd UNNEEDED, const char *name UNNEEDED,
 				    const char *buffer UNNEEDED, const jsmntok_t *tok UNNEEDED,
@@ -404,6 +409,9 @@ u8 *towire_channel_dev_reenable_commit(const tal_t *ctx UNNEEDED)
 /* Generated stub for towire_channel_send_shutdown */
 u8 *towire_channel_send_shutdown(const tal_t *ctx UNNEEDED)
 { fprintf(stderr, "towire_channel_send_shutdown called!\n"); abort(); }
+/* Generated stub for towire_channel_specific_feerates */
+u8 *towire_channel_specific_feerates(const tal_t *ctx UNNEEDED, u32 feerate_base UNNEEDED, u32 feerate_ppm UNNEEDED)
+{ fprintf(stderr, "towire_channel_specific_feerates called!\n"); abort(); }
 /* Generated stub for towire_connectctl_connect_to_peer */
 u8 *towire_connectctl_connect_to_peer(const tal_t *ctx UNNEEDED, const struct pubkey *id UNNEEDED, u32 seconds_waited UNNEEDED, const struct wireaddr_internal *addrhint UNNEEDED)
 { fprintf(stderr, "towire_connectctl_connect_to_peer called!\n"); abort(); }

wallet/test/run-wallet.c

@@ -210,7 +210,7 @@ void json_add_amount_msat(struct json_stream *result UNNEEDED,
 void json_add_amount_sat(struct json_stream *result UNNEEDED,
 			 struct amount_sat sat UNNEEDED,
 			 const char *rawfieldname UNNEEDED,
-			 const char *satfieldname)
+			 const char *msatfieldname)
 
 { fprintf(stderr, "json_add_amount_sat called!\n"); abort(); }
 /* Generated stub for json_add_bool */
@@ -371,6 +371,11 @@ struct command_result *param_loglevel(struct command *cmd UNNEEDED,
 				      const jsmntok_t *tok UNNEEDED,
 				      enum log_level **level UNNEEDED)
 { fprintf(stderr, "param_loglevel called!\n"); abort(); }
+/* Generated stub for param_msat */
+struct command_result *param_msat(struct command *cmd UNNEEDED, const char *name UNNEEDED,
+				  const char *buffer UNNEEDED, const jsmntok_t *tok UNNEEDED,
+				  struct amount_msat **msat UNNEEDED)
+{ fprintf(stderr, "param_msat called!\n"); abort(); }
 /* Generated stub for param_number */
 struct command_result *param_number(struct command *cmd UNNEEDED, const char *name UNNEEDED,
 				    const char *buffer UNNEEDED, const jsmntok_t *tok UNNEEDED,
@@ -492,6 +497,9 @@ u8 *towire_channel_sending_commitsig_reply(const tal_t *ctx UNNEEDED)
 /* Generated stub for towire_channel_send_shutdown */
 u8 *towire_channel_send_shutdown(const tal_t *ctx UNNEEDED)
 { fprintf(stderr, "towire_channel_send_shutdown called!\n"); abort(); }
+/* Generated stub for towire_channel_specific_feerates */
+u8 *towire_channel_specific_feerates(const tal_t *ctx UNNEEDED, u32 feerate_base UNNEEDED, u32 feerate_ppm UNNEEDED)
+{ fprintf(stderr, "towire_channel_specific_feerates called!\n"); abort(); }
 /* Generated stub for towire_connectctl_connect_to_peer */
 u8 *towire_connectctl_connect_to_peer(const tal_t *ctx UNNEEDED, const struct pubkey *id UNNEEDED, u32 seconds_waited UNNEEDED, const struct wireaddr_internal *addrhint UNNEEDED)
 { fprintf(stderr, "towire_connectctl_connect_to_peer called!\n"); abort(); }