chanbackup: make getemergencyrecoverdata rpc more verbose

Adding more information to geremergencyrecoverdata, to let users know if they are using
legacy file format and the list of all the backed up channel ids.

Key Changes:
 - Added:
   1. can_create_penalty: To let user know if they need to update the file.
   2. backed_up_channel_ids: List of all the backed up channels

Author: adi2011

contrib/msggen/msggen/schema.json

@@ -14058,7 +14058,9 @@
       },
       "response": {
         "required": [
-          "filedata"
+          "filedata",
+          "can_create_penalty",
+          "backed_up_channel_ids"
         ],
         "additionalProperties": false,
         "properties": {
@@ -14067,6 +14069,21 @@
             "description": [
               "The raw, hex-encoded, emergency.recover file"
             ]
+          },
+          "can_create_penalty": {
+            "type": "boolean",
+            "description": [
+              "If false, you are using legacy file version, which can not create penalty transactions, kindly delete emergency.recover and restart the node!"
+            ]
+          },
+          "backed_up_channel_ids": {
+            "type": "array",
+            "items": {
+              "type": "hex",
+              "description": [
+                "Channel IDs of channels backed up inside emergency.recover"
+              ]
+            }
           }
         }
       },

doc/schemas/getemergencyrecoverdata.json

@@ -13,7 +13,9 @@
   },
   "response": {
     "required": [
-      "filedata"
+      "filedata",
+      "can_create_penalty",
+      "backed_up_channel_ids"
     ],
     "additionalProperties": false,
     "properties": {
@@ -22,6 +24,21 @@
         "description": [
           "The raw, hex-encoded, emergency.recover file"
         ]
+      },
+      "can_create_penalty": {
+        "type": "boolean",
+        "description": [
+          "If false, you are using legacy file version, which can not create penalty transactions, kindly delete emergency.recover and restart the node!"
+        ]
+      },
+      "backed_up_channel_ids": {
+        "type": "array",
+        "items": {
+          "type": "hex",
+          "description": [
+            "Channel IDs of channels backed up inside emergency.recover"
+          ]
+        }
       }
     }
   },

plugins/chanbackup.c

@@ -316,6 +316,35 @@ static struct modern_scb_chan *convert_from_legacy(const tal_t *ctx, struct lega
 	return modern_scb_tlv;
 }
 
+/* Reads WIRE_STATIC_CHAN_BACKUP and converts from legacy_scb_chan to modern_scb_chan, if required. */
+static void read_static_chan_backup(struct command *cmd, const u8 *blob, u64 *version, u32 *timestamp, struct modern_scb_chan ***scb_tlvs, bool *is_converted) {
+	bool is_tlvs = false;
+	struct legacy_scb_chan **scb;
+
+	if(!fromwire_static_chan_backup(cmd,
+					blob,
+					version,
+					timestamp,
+					&scb)) {
+		is_tlvs = true;
+		if (!fromwire_static_chan_backup_with_tlvs(cmd,
+							   blob,
+							   version,
+							   timestamp,
+							   scb_tlvs)) {
+			plugin_err(cmd->plugin, "Corrupted SCB!");
+		}
+	}
+	*is_converted = !is_tlvs;
+	if (!is_tlvs) {
+		*scb_tlvs = tal_count(scb) ? tal_arr(cmd, struct modern_scb_chan *, tal_count(scb)): NULL;
+		for (size_t i=0; i < tal_count(scb); i++){
+			(*scb_tlvs)[i] = convert_from_legacy(cmd, scb[i]);
+		}
+	}
+	return;
+}
+
 /* Recovers the channels by making RPC to `recoverchannel` */
 static struct command_result *json_emergencyrecover(struct command *cmd,
 						    const char *buf,
@@ -324,28 +353,14 @@ static struct command_result *json_emergencyrecover(struct command *cmd,
 	struct out_req *req;
 	u64 version;
 	u32 timestamp;
-	struct legacy_scb_chan **scb;
+	bool is_converted;
 	struct modern_scb_chan **scb_tlvs;
 
 	if (!param(cmd, buf, params, NULL))
 		return command_param_failed();
 
 	u8 *res = decrypt_scb(cmd->plugin);
-	bool is_tlvs = false;
-	if (!fromwire_static_chan_backup(cmd,
-                                         res,
-                                         &version,
-                                         &timestamp,
-                                         &scb)) {
-		if(!fromwire_static_chan_backup_with_tlvs(cmd,
-							  res,
-							  &version,
-							  &timestamp,
-							  &scb_tlvs)) {
-			plugin_err(cmd->plugin, "Corrupted SCB!");
-		}
-		is_tlvs = true;
-	}
+	read_static_chan_backup(cmd, res, &version, &timestamp, &scb_tlvs, &is_converted);
 
 	if ((version & 0x5555555555555555ULL) != (VERSION & 0x5555555555555555ULL)) {
 		plugin_err(cmd->plugin,
@@ -356,26 +371,18 @@ static struct command_result *json_emergencyrecover(struct command *cmd,
 				    after_recover_rpc,
 				    forward_error, NULL);
 
-	json_array_start(req->js, "scb");
-	if (is_tlvs) {
-		for (size_t i=0; i<tal_count(scb_tlvs); i++) {
-			u8 *scb_hex = tal_arr(cmd, u8, 0);
-			towire_modern_scb_chan(&scb_hex,scb_tlvs[i]);
-			json_add_hex_talarr(req->js, NULL, scb_hex);
-		}
-	} else {
+	if (is_converted) {
 		plugin_notify_message(cmd, LOG_DBG, "Processing legacy emergency.recover file format. "
-				      "Please migrate to the latest file format for improved "
-				      "compatibility and fund recovery.");
-
-		for (size_t i=0; i<tal_count(scb); i++) {
-			u8 *scb_hex = tal_arr(cmd, u8, 0);
-			struct modern_scb_chan *tmp_scb = convert_from_legacy(cmd, scb[i]);
-			towire_modern_scb_chan(&scb_hex, tmp_scb);
-			json_add_hex_talarr(req->js, NULL, scb_hex);
-		}
+			"Please migrate to the latest file format for improved "
+			"compatibility and fund recovery.");
 	}
 
+	json_array_start(req->js, "scb");
+	for (size_t i=0; i<tal_count(scb_tlvs); i++) {
+		u8 *scb_hex = tal_arr(cmd, u8, 0);
+		towire_modern_scb_chan(&scb_hex, scb_tlvs[i]);
+		json_add_hex_talarr(req->js, NULL, scb_hex);
+	}
 	json_array_end(req->js);
 
 	return send_outreq(req);
@@ -946,8 +953,8 @@ static struct command_result *after_latestscb(struct command *cmd,
 {
         u64 version;
 	u32 timestamp;
+	bool is_converted;
 	struct modern_scb_chan **scb_tlvs;
-	struct legacy_scb_chan **scb;
         struct json_stream *response;
         struct out_req *req;
 
@@ -959,21 +966,7 @@ static struct command_result *after_latestscb(struct command *cmd,
 		return command_finished(cmd, response);
         }
 
-	bool is_tlvs = false;
-	if (!fromwire_static_chan_backup(cmd,
-                                         res,
-                                         &version,
-                                         &timestamp,
-                                         &scb)) {
-		if(!fromwire_static_chan_backup_with_tlvs(cmd,
-							  res,
-							  &version,
-							  &timestamp,
-							  &scb_tlvs)) {
-			plugin_err(cmd->plugin, "Corrupted SCB!");
-		}
-		is_tlvs = true;
-	}
+	read_static_chan_backup(cmd, res, &version, &timestamp, &scb_tlvs, &is_converted);
 
 	if ((version & 0x5555555555555555ULL) != (VERSION & 0x5555555555555555ULL)) {
 		plugin_err(cmd->plugin,
@@ -985,28 +978,11 @@ static struct command_result *after_latestscb(struct command *cmd,
 				    &forward_error, NULL);
 
 	json_array_start(req->js, "scb");
-	if (is_tlvs) {
-		for (size_t i=0; i<tal_count(scb_tlvs); i++) {
-			u8 *scb_hex = tal_arr(cmd, u8, 0);
-			towire_modern_scb_chan(&scb_hex,scb_tlvs[i]);
-			json_add_hex_talarr(req->js, NULL, scb_hex);
-		}
-	} else {
-		for (size_t i=0; i<tal_count(scb); i++) {
-			u8 *scb_hex = tal_arr(cmd, u8, 0);
-			struct modern_scb_chan *tmp_scb_tlv = tal(cmd, struct modern_scb_chan);
-			tmp_scb_tlv->id = scb[i]->id;
-			tmp_scb_tlv->addr = scb[i]->addr;
-			tmp_scb_tlv->cid = scb[i]->cid;
-			tmp_scb_tlv->funding = scb[i]->funding;
-			tmp_scb_tlv->funding_sats = scb[i]->funding_sats;
-			tmp_scb_tlv->type = scb[i]->type;
-			tmp_scb_tlv->tlvs = tlv_scb_tlvs_new(cmd);
-			towire_modern_scb_chan(&scb_hex, tmp_scb_tlv);
-			json_add_hex_talarr(req->js, NULL, scb_hex);
-		}
+	for (size_t i=0; i<tal_count(scb_tlvs); i++) {
+		u8 *scb_hex = tal_arr(cmd, u8, 0);
+		towire_modern_scb_chan(&scb_hex, scb_tlvs[i]);
+		json_add_hex_talarr(req->js, NULL, scb_hex);
 	}
-
 	json_array_end(req->js);
 
 	return send_outreq(req);
@@ -1040,7 +1016,21 @@ static struct command_result *json_getemergencyrecoverdata(struct command *cmd,
 	response = jsonrpc_stream_success(cmd);
 	json_add_hex_talarr(response, "filedata", filedata);
 
-
+	// Add details about the SCB.
+	const u8 *decrypted_filedata = decrypt_scb(cmd->plugin);
+	u64 version;
+	u32 timestamp;
+	struct modern_scb_chan **scb_tlvs;
+	bool is_converted;
+	read_static_chan_backup(cmd, decrypted_filedata, &version, &timestamp, &scb_tlvs, &is_converted);
+
+	// If false, update the emergency.recover file immediately! 
+	json_add_bool(response, "can_create_penalty", !is_converted);
+	json_array_start(response, "backed_up_channel_ids");
+	for (int i = 0; i < tal_count(scb_tlvs); i++) {
+		json_add_channel_id(response, NULL, &scb_tlvs[i]->cid);
+	}
+	json_array_end(response);
 	return command_finished(cmd, response);
 }
 

tests/test_misc.py

@@ -2973,8 +2973,10 @@ def test_getemergencyrecoverdata(node_factory):
     Test getemergencyrecoverdata
     """
     l1 = node_factory.get_node()
-    filedata = l1.rpc.getemergencyrecoverdata()['filedata']
-
+    rpc = l1.rpc.getemergencyrecoverdata()
+    filedata = rpc['filedata']
+    assert rpc['can_create_penalty'] == True
+    assert len(rpc['backed_up_channel_ids']) == 0
     with open(os.path.join(l1.daemon.lightning_dir, TEST_NETWORK, "emergency.recover"), "rb") as f:
         lines = f.read().hex()
     assert lines == filedata