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synchronizer: rm redundant get_history call if new block mined unconf

This is an optimisation and possible hardening against traffic analysis.

After a new block is mined, we sometimes receive "blockchain.scripthash.subscribe" notifications. If so, this is often due to the just mined block including mempool txs we already knew about.

Normally we would call the "blockchain.scripthash.get_history" RPC, to get full history of the affected scripthash.
Instead now we first optimistically guess that all mempool txs touching this scripthash just got mined and see if by assuming that we can reproduce the announced sh status.
- if yes, we saved a network RTT by not having to call "blockchain.scripthash.get_history"
- if no, we request the history from the server using the RPC
This commit is contained in:
SomberNight
2025-10-29 18:51:53 +00:00
parent 5212d20f29
commit 6d016d70ee
2 changed files with 163 additions and 9 deletions

View File

@@ -160,7 +160,18 @@ class Synchronizer(SynchronizerBase):
and not self._stale_histories
and self.status_queue.empty())
async def _maybe_request_history_for_addr(self, addr: str) -> List[dict]:
async def _maybe_request_history_for_addr(self, addr: str, *, ann_status: Optional[str]) -> List[dict]:
# First opportunistically try to guess the addr history. Might save us network requests.
old_history = self.adb.db.get_addr_history(addr)
def guess_height(old_height: int) -> int:
if old_height in (0, -1,):
return self.interface.tip # maybe mempool tx got mined just now
return old_height
guessed_history = [(txid, guess_height(old_height)) for (txid, old_height) in old_history]
if history_status(guessed_history) == ann_status:
self.logger.debug(f"managed to guess new history for {addr}. won't call 'blockchain.scripthash.get_history'.")
return [{"height": height, "tx_hash": txid} for (txid, height) in guessed_history]
# request addr history from server
sh = address_to_scripthash(addr)
self._requests_sent += 1
async with self._network_request_semaphore:
@@ -183,7 +194,7 @@ class Synchronizer(SynchronizerBase):
self._stale_histories.pop(addr, asyncio.Future()).cancel()
finally:
self._handling_addr_statuses.discard(addr)
result = await self._maybe_request_history_for_addr(addr)
result = await self._maybe_request_history_for_addr(addr, ann_status=status)
hist = list(map(lambda item: (item['tx_hash'], item['height']), result))
# tx_fees
tx_fees = [(item['tx_hash'], item.get('fee')) for item in result]

View File

@@ -1,5 +1,6 @@
import asyncio
import collections
from typing import Optional, Sequence, Iterable
import aiorpcx
from aiorpcx import RPCError
@@ -12,8 +13,13 @@ from electrum.logging import Logger
from electrum.simple_config import SimpleConfig
from electrum.transaction import Transaction
from electrum import constants
from electrum.wallet import Abstract_Wallet
from electrum.blockchain import Blockchain
from electrum.bitcoin import script_to_scripthash
from electrum.synchronizer import history_status
from . import ElectrumTestCase
from . import restore_wallet_from_text__for_unittest
class TestServerAddr(ElectrumTestCase):
@@ -86,6 +92,10 @@ class MockNetwork:
pass
async def switch_lagging_interface(self):
pass
def blockchain(self) -> Blockchain:
return self.interface.blockchain
def get_local_height(self) -> int:
return self.blockchain().height()
# regtest chain:
@@ -106,11 +116,11 @@ BLOCK_HEADERS = {
}
_active_server_sessions = set()
def _get_active_server_session() -> 'ServerSession':
def _get_active_server_session() -> 'ToyServerSession':
assert 1 == len(_active_server_sessions), len(_active_server_sessions)
return list(_active_server_sessions)[0]
class ServerSession(aiorpcx.RPCSession, Logger):
class ToyServerSession(aiorpcx.RPCSession, Logger):
def __init__(self, *args, **kwargs):
aiorpcx.RPCSession.__init__(self, *args, **kwargs)
@@ -120,6 +130,12 @@ class ServerSession(aiorpcx.RPCSession, Logger):
self.txs = {
"bdae818ad3c1f261317738ae9284159bf54874356f186dbc7afd631dc1527fcb": bfh("020000000001010000000000000000000000000000000000000000000000000000000000000000ffffffff025100ffffffff0200f2052a010000001600140297bde2689a3c79ffe050583b62f86f2d9dae540000000000000000266a24aa21a9ede2f61c3f71d1defd3fa999dfa36953755c690689799962b48bebd836974e8cf90120000000000000000000000000000000000000000000000000000000000000000000000000"),
} # type: dict[str, bytes]
self.txid_to_block_height = collections.defaultdict(int) # type: dict[str, int]
self.subbed_headers = False
self.notified_height = None # type: Optional[int]
self.subbed_scripthashes = set() # type: set[str]
self.sh_to_funding_txids = collections.defaultdict(set) # type: dict[str, set[str]]
self.sh_to_spending_txids = collections.defaultdict(set) # type: dict[str, set[str]]
self._method_counts = collections.defaultdict(int) # type: dict[str, int]
_active_server_sessions.add(self)
@@ -136,8 +152,11 @@ class ServerSession(aiorpcx.RPCSession, Logger):
'blockchain.headers.subscribe': self._handle_headers_subscribe,
'blockchain.block.header': self._handle_block_header,
'blockchain.block.headers': self._handle_block_headers,
'blockchain.scripthash.subscribe': self._handle_scripthash_subscribe,
'blockchain.scripthash.get_history': self._handle_scripthash_get_history,
'blockchain.transaction.get': self._handle_transaction_get,
'blockchain.transaction.broadcast': self._handle_transaction_broadcast,
'blockchain.transaction.get_merkle': self._handle_transaction_get_merkle,
'server.ping': self._handle_ping,
}
handler = handlers.get(request.method)
@@ -162,9 +181,13 @@ class ServerSession(aiorpcx.RPCSession, Logger):
async def _handle_estimatefee(self, number, mode=None):
return 1000
async def _handle_headers_subscribe(self):
def _get_headersub_result(self):
return {'hex': BLOCK_HEADERS[self.cur_height].hex(), 'height': self.cur_height}
async def _handle_headers_subscribe(self):
self.subbed_headers = True
return self._get_headersub_result()
async def _handle_block_header(self, height):
return BLOCK_HEADERS[height].hex()
@@ -186,10 +209,97 @@ class ServerSession(aiorpcx.RPCSession, Logger):
raise RPCError(DAEMON_ERROR, f'daemon error: unknown txid={tx_hash}')
return rawtx.hex()
async def _handle_transaction_broadcast(self, raw_tx: str):
async def _handle_transaction_get_merkle(self, tx_hash: str, height: int) -> dict:
# Fake stuff. Client will ignore it due to config.NETWORK_SKIPMERKLECHECK
return {
"merkle":
[
"713d6c7e6ce7bbea708d61162231eaa8ecb31c4c5dd84f81c20409a90069cb24",
"03dbaec78d4a52fbaf3c7aa5d3fccd9d8654f323940716ddf5ee2e4bda458fde",
"e670224b23f156c27993ac3071940c0ff865b812e21e0a162fe7a005d6e57851",
"369a1619a67c3108a8850118602e3669455c70cdcdb89248b64cc6325575b885",
"4756688678644dcb27d62931f04013254a62aeee5dec139d1aac9f7b1f318112",
"7b97e73abc043836fd890555bfce54757d387943a6860e5450525e8e9ab46be5",
"61505055e8b639b7c64fd58bce6fc5c2378b92e025a02583303f69930091b1c3",
"27a654ff1895385ac14a574a0415d3bbba9ec23a8774f22ec20d53dd0b5386ff",
"5312ed87933075e60a9511857d23d460a085f3b6e9e5e565ad2443d223cfccdc",
"94f60b14a9f106440a197054936e6fb92abbd69d6059b38fdf79b33fc864fca0",
"2d64851151550e8c4d337f335ee28874401d55b358a66f1bafab2c3e9f48773d"
],
"block_height": height,
"pos": 710,
}
async def _handle_transaction_broadcast(self, raw_tx: str) -> str:
tx = Transaction(raw_tx)
self.txs[tx.txid()] = bfh(raw_tx)
return tx.txid()
txid = tx.txid()
self.txs[txid] = bfh(raw_tx)
touched_sh = await self._process_added_tx(txid=txid)
if touched_sh:
await self._send_notifications(touched_sh=touched_sh)
return txid
async def _process_added_tx(self, *, txid: str) -> set[str]:
"""Returns touched scripthashes."""
tx = Transaction(self.txs[txid])
touched_sh = set()
# update sh_to_funding_txids
for txout in tx.outputs():
sh = script_to_scripthash(txout.scriptpubkey)
self.sh_to_funding_txids[sh].add(txid)
touched_sh.add(sh)
# update sh_to_spending_txids
for txin in tx.inputs():
if parent_tx_raw := self.txs.get(txin.prevout.txid.hex()):
parent_tx = Transaction(parent_tx_raw)
ptxout = parent_tx.outputs()[txin.prevout.out_idx]
sh = script_to_scripthash(ptxout.scriptpubkey)
self.sh_to_spending_txids[sh].add(txid)
touched_sh.add(sh)
return touched_sh
async def _handle_scripthash_subscribe(self, sh: str) -> Optional[str]:
self.subbed_scripthashes.add(sh)
hist = self._calc_sh_history(sh)
return history_status(hist)
async def _handle_scripthash_get_history(self, sh: str) -> Sequence[dict]:
hist_tuples = self._calc_sh_history(sh)
hist_dicts = [{"height": height, "tx_hash": txid} for (txid, height) in hist_tuples]
for hist_dict in hist_dicts: # add "fee" key for mempool txs
if hist_dict["height"] in (0, -1,):
hist_dict["fee"] = 0
return hist_dicts
def _calc_sh_history(self, sh: str) -> Sequence[tuple[str, int]]:
txids = self.sh_to_funding_txids[sh] | self.sh_to_spending_txids[sh]
hist = []
for txid in txids:
bh = self.txid_to_block_height[txid]
hist.append((txid, bh))
hist.sort(key=lambda x: x[1]) # FIXME put mempool txs last
return hist
async def _send_notifications(self, *, touched_sh: Iterable[str], height_changed: bool = False) -> None:
if height_changed and self.subbed_headers and self.notified_height != self.cur_height:
self.notified_height = self.cur_height
args = (self._get_headersub_result(),)
await self.send_notification('blockchain.headers.subscribe', args)
touched_sh = set(sh for sh in touched_sh if sh in self.subbed_scripthashes)
for sh in touched_sh:
hist = self._calc_sh_history(sh)
args = (sh, history_status(hist))
await self.send_notification("blockchain.scripthash.subscribe", args)
async def mine_block(self, *, txids_mined: Iterable[str] = None):
if txids_mined is None:
txids_mined = []
self.cur_height += 1
touched_sh = set()
for txid in txids_mined:
self.txid_to_block_height[txid] = self.cur_height
touched_sh |= await self._process_added_tx(txid=txid)
await self._send_notifications(touched_sh=touched_sh, height_changed=True)
class TestInterface(ElectrumTestCase):
@@ -198,6 +308,7 @@ class TestInterface(ElectrumTestCase):
def setUp(self):
super().setUp()
self.config = SimpleConfig({'electrum_path': self.electrum_path})
self.config.NETWORK_SKIPMERKLECHECK = True
self._orig_WAIT_FOR_BUFFER_GROWTH_SECONDS = PaddedRSTransport.WAIT_FOR_BUFFER_GROWTH_SECONDS
PaddedRSTransport.WAIT_FOR_BUFFER_GROWTH_SECONDS = 0
@@ -207,7 +318,7 @@ class TestInterface(ElectrumTestCase):
async def asyncSetUp(self):
await super().asyncSetUp()
self._server: asyncio.base_events.Server = await aiorpcx.serve_rs(ServerSession, "127.0.0.1")
self._server: asyncio.base_events.Server = await aiorpcx.serve_rs(ToyServerSession, "127.0.0.1")
server_socket_addr = self._server.sockets[0].getsockname()
self._server_port = server_socket_addr[1]
self.network = MockNetwork(config=self.config)
@@ -255,3 +366,35 @@ class TestInterface(ElectrumTestCase):
rawtx2 = await interface.get_transaction(tx.txid())
self.assertEqual(rawtx1, rawtx2)
self.assertEqual(_get_active_server_session()._method_counts["blockchain.transaction.get"], 0)
async def test_dont_request_gethistory_if_status_change_results_from_mempool_txs_simply_getting_mined(self):
"""After a new block is mined, we recv "blockchain.scripthash.subscribe" notifs.
We opportunistically guess the scripthash status changed purely because touching mempool txs just got mined.
If the guess is correct, we won't call the "blockchain.scripthash.get_history" RPC.
"""
interface = await self._start_iface_and_wait_for_sync()
w1 = restore_wallet_from_text__for_unittest("9dk", path=None, config=self.config)['wallet'] # type: Abstract_Wallet
w1.start_network(self.network)
await w1.up_to_date_changed_event.wait()
self.assertEqual(_get_active_server_session()._method_counts["blockchain.scripthash.get_history"], 0)
# fund w1 (in mempool)
funding_tx = "01000000000101e855888b77b1688d08985b863bfe85b354049b4eba923db9b5cf37089975d5d10000000000fdffffff0280969800000000001600140297bde2689a3c79ffe050583b62f86f2d9dae5460abe9000000000016001472df47551b6e7e0c8428814d2e572bc5ac773dda024730440220383efa2f0f5b87f8ce5d6b6eaf48cba03bf522b23fbb23b2ac54ff9d9a8f6a8802206f67d1f909f3c7a22ac0308ac4c19853ffca3a9317e1d7e0c88cc3a86853aaac0121035061949222555a0df490978fe6e7ebbaa96332ecb5c266918fd800c0eef736e7358d1400"
funding_txid = await _get_active_server_session()._handle_transaction_broadcast(funding_tx)
await w1.up_to_date_changed_event.wait()
while not w1.is_up_to_date():
await w1.up_to_date_changed_event.wait()
self.assertEqual(_get_active_server_session()._method_counts["blockchain.scripthash.get_history"], 1)
self.assertEqual(
w1.adb.get_address_history("bcrt1qq2tmmcngng78nllq2pvrkchcdukemtj5jnxz44"),
{funding_txid: 0})
# mine funding tx
await _get_active_server_session().mine_block(txids_mined=[funding_txid])
await w1.up_to_date_changed_event.wait()
while not w1.is_up_to_date():
await w1.up_to_date_changed_event.wait()
# see if we managed to guess new history, and hence did not need to call get_history RPC
self.assertEqual(_get_active_server_session()._method_counts["blockchain.scripthash.get_history"], 1)
self.assertEqual(
w1.adb.get_address_history("bcrt1qq2tmmcngng78nllq2pvrkchcdukemtj5jnxz44"),
{funding_txid: 7})