feat: add option to setchannelfee for all channels

- This will make a channel loop when 'id' argument was "all".
- The response will now contain an array of objects (peer_id, scid, ...)
- It will skip channels in invalid states.
- Moves iffy channel/peer param stuff to param_channel_or_all

lightningd/peer_control.c

@@ -1339,6 +1339,43 @@ static const struct json_command getinfo_command = {
 };
 AUTODATA(json_command, &getinfo_command);
 
+static struct command_result *param_channel_or_all(struct command *cmd,
+					     const char *name,
+					     const char *buffer,
+					     const jsmntok_t *tok,
+					     struct channel **channel)
+{
+	struct command_result *res;
+	struct peer *peer;
+
+	/* early return the easy case */
+	if (json_tok_streq(buffer, tok, "all")) {
+		*channel = NULL;
+		return NULL;
+	}
+
+	/* Find channel by peer_id */
+	peer = peer_from_json(cmd->ld, buffer, tok);
+	if (peer) {
+		*channel = peer_active_channel(peer);
+		if (!*channel)
+			return command_fail(cmd, LIGHTNINGD,
+					"Could not find active channel of peer with that id");
+		return NULL;
+
+	/* Find channel by id or scid */
+	} else {
+		res = command_find_channel(cmd, buffer, tok, 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");
+		return NULL;
+	}
+}
+
 /* Fee base is a u32, but it's convenient to let them specify it using
  * msat etc. suffix. */
 static struct command_result *param_msat_u32(struct command *cmd,
@@ -1367,22 +1404,47 @@ static struct command_result *param_msat_u32(struct command *cmd,
 	return NULL;
 }
 
+static void set_channel_fees(struct command *cmd, struct channel *channel,
+		u32 base, u32 ppm, struct json_stream *response)
+{
+	struct channel_id cid;
+
+	/* set new values */
+	channel->feerate_base = 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(NULL, base, ppm)));
+
+	/* save values to database */
+	wallet_channel_save(cmd->ld->wallet, channel);
+
+	/* write JSON response entry */
+	derive_channel_id(&cid, &channel->funding_txid, channel->funding_outnum);
+	json_object_start(response, NULL);
+	json_add_pubkey(response, "peer_id", &channel->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);
+}
+
 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;
 	u32 *base, *ppm;
 
 	/* Parse the JSON command */
 	if (!param(cmd, buffer, params,
-		   p_req("id", param_tok, &idtok),
+		   p_req("id", param_channel_or_all, &channel),
 		   p_opt_def("base", param_msat_u32,
 			     &base, cmd->ld->config.fee_base),
 		   p_opt_def("ppm", param_number, &ppm,
@@ -1390,55 +1452,38 @@ static struct command_result *json_setchannelfee(struct command *cmd,
 		   NULL))
 		return command_param_failed();
 
-	/* Find the channel */
-	peer = peer_from_json(cmd->ld, buffer, idtok);
-	if (peer) {
+	/* Open JSON response object for later iteration */
+	response = json_stream_success(cmd);
+	json_object_start(response, NULL);
+	json_add_num(response, "base", *base);
+	json_add_num(response, "ppm", *ppm);
+	json_array_start(response, "channels");
+
+	/* If the users requested 'all' channels we need to iterate */
+	if (channel == NULL) {
+		list_for_each(&cmd->ld->peers, peer, list) {
+			list_for_each(&peer->channels, channel, list) {
 				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;
+					continue;
+				if (channel->state != CHANNELD_NORMAL &&
+					channel->state != CHANNELD_AWAITING_LOCKIN)
+					continue;
+				set_channel_fees(cmd, channel, *base, *ppm, response);
+			}
 		}
 
+	/* single channel should be updated */
+	} else {
 		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_channel_fees(cmd, channel, *base, *ppm, response);
+	}
 
-	/* set, notify and save new values */
-	channel->feerate_base = *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(NULL,
-						      *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", *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);
+	/* Close and return response */
+	json_array_end(response);
 	json_object_end(response);
 	return command_success(cmd, response);
 }