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Peer storage enhancements #8422

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e201dbb
chanbackup: Store the latest recvd peer storage only
adi2011 Jul 22, 2025
854529d
chanbackup: make getemergencyrecoverdata rpc more verbose
adi2011 Jul 22, 2025
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19 changes: 18 additions & 1 deletion contrib/msggen/msggen/schema.json
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Original file line number Diff line number Diff line change
Expand Up @@ -13860,7 +13860,9 @@
},
"response": {
"required": [
"filedata"
"filedata",
"can_create_penalty",
"backed_up_channel_ids"
],
"additionalProperties": false,
"properties": {
Expand All @@ -13869,6 +13871,21 @@
"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"
]
}
}
}
},
Expand Down
19 changes: 18 additions & 1 deletion doc/schemas/getemergencyrecoverdata.json
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Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,9 @@
},
"response": {
"required": [
"filedata"
"filedata",
"can_create_penalty",
"backed_up_channel_ids"
],
"additionalProperties": false,
"properties": {
Expand All @@ -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"
]
}
}
}
},
Expand Down
186 changes: 107 additions & 79 deletions plugins/chanbackup.c
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Original file line number Diff line number Diff line change
Expand Up @@ -323,6 +323,35 @@ 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,
Expand All @@ -331,28 +360,14 @@ 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,
Expand All @@ -363,26 +378,18 @@ 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);
Expand Down Expand Up @@ -807,6 +814,48 @@ static struct command_result *datastore_failed(struct command *cmd,
return command_hook_success(cmd);
}

/* Compares the data between the stored scb and latest recvd scb, stores the most
* recent one only. */
static struct command_result *store_latest_scb(struct command *cmd,
const u8 *latest_stored_scb,
u8 *received_scb)
{
size_t stored_scb_len = tal_bytelen(latest_stored_scb);
size_t recvd_scb_len = tal_bytelen(received_scb);
const u8 *recvd_scb_const = received_scb;

if (stored_scb_len == 0)
goto store_data;

// We only need the timestamps, so instead of fully deserializing with `fromwire_static_chan_backup`,
// we manually parse just enough fields to reach the timestamp in each SCB blob.
assert(fromwire_u16(&latest_stored_scb, &stored_scb_len) == WIRE_STATIC_CHAN_BACKUP);
assert(fromwire_u16(&recvd_scb_const, &recvd_scb_len) == WIRE_STATIC_CHAN_BACKUP);

// Fetching version from the SCB.
fromwire_u64(&latest_stored_scb, &stored_scb_len);
fromwire_u64(&recvd_scb_const, &recvd_scb_len);

u32 timestamp = fromwire_u32(&latest_stored_scb, &stored_scb_len);
u32 timestamp_new = fromwire_u32(&recvd_scb_const, &recvd_scb_len);

if (timestamp_new > timestamp)
goto store_data;

plugin_log(cmd->plugin, LOG_DBG, "Ignoring old Peer Storage");
return command_hook_success(cmd);

store_data:
return jsonrpc_set_datastore_binary(cmd,
"chanbackup/latestscb",
received_scb,
"create-or-replace",
datastore_success,
datastore_failed,
"Saving latestscb");

}

static struct command_result *handle_your_peer_storage(struct command *cmd,
const char *buf,
const jsmntok_t *params)
Expand Down Expand Up @@ -895,14 +944,10 @@ static struct command_result *handle_your_peer_storage(struct command *cmd,
return failed_peer_restore(cmd, &node_id,
"Peer altered our data");


return jsonrpc_set_datastore_binary(cmd,
"chanbackup/latestscb",
decoded_bkp,
"create-or-replace",
datastore_success,
datastore_failed,
"Saving latestscb");
return jsonrpc_get_datastore_binary(cmd,
"chanbackup/latestscb",
store_latest_scb,
decoded_bkp);
} else {
/* Any other message we ignore */
return command_hook_success(cmd);
Expand All @@ -915,8 +960,8 @@ 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;

Expand All @@ -928,21 +973,7 @@ 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,
Expand All @@ -954,28 +985,11 @@ 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);
Expand Down Expand Up @@ -1009,7 +1023,21 @@ 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);
}

Expand Down
6 changes: 4 additions & 2 deletions tests/test_misc.py
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Original file line number Diff line number Diff line change
Expand Up @@ -2941,8 +2941,10 @@ 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
Expand Down
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