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assumeUTXO: fix peers disconnection during sync

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Because AssumeUTXO nodes prioritize tip synchronization, they relay their local
address through the network before completing the background chain sync.
This, combined with the advertising of full-node service (NODE_NETWORK), can
result in an honest peer in IBD connecting to the AssumeUTXO node (while syncing)
and requesting an historical block the node does not have. This behavior leads to
an abrupt disconnection due to perceived unresponsiveness (lack of response)
from the AssumeUTXO node.

This lack of response occurs because nodes ignore getdata requests when they do
not have the block data available (further discussion can be found in PR 30385).

Fix this by refraining from signaling full-node service support while the
background chain is being synced. During this period, the node will only
signal 'NODE_NETWORK_LIMITED' support. Then, full-node ('NODE_NETWORK')
support will be re-enabled once the background chain sync is completed.
This commit is contained in:
furszy
2024-09-03 11:00:55 -03:00
parent 93e48240bf
commit 6d5812e5c8
7 changed files with 70 additions and 10 deletions
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36
test/functional/feature_assumeutxo.py
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@ -248,6 +248,11 @@ class AssumeutxoTest(BitcoinTestFramework):
node1.submitheader(main_block1)
node1.submitheader(main_block2)
def assert_only_network_limited_service(self, node):
node_services = node.getnetworkinfo()['localservicesnames']
assert 'NETWORK' not in node_services
assert 'NETWORK_LIMITED' in node_services
def run_test(self):
"""
Bring up two (disconnected) nodes, mine some new blocks on the first,
@ -381,6 +386,9 @@ class AssumeutxoTest(BitcoinTestFramework):
self.test_snapshot_block_invalidated(dump_output['path'])
self.test_snapshot_not_on_most_work_chain(dump_output['path'])
# Prune-node sanity check
assert 'NETWORK' not in n1.getnetworkinfo()['localservicesnames']
self.log.info(f"Loading snapshot into second node from {dump_output['path']}")
# This node's tip is on an ancestor block of the snapshot, which should
# be the normal case
@ -388,6 +396,10 @@ class AssumeutxoTest(BitcoinTestFramework):
assert_equal(loaded['coins_loaded'], SNAPSHOT_BASE_HEIGHT)
assert_equal(loaded['base_height'], SNAPSHOT_BASE_HEIGHT)
self.log.info("Confirm that local services remain unchanged")
# Since n1 is a pruned node, the 'NETWORK' service flag must always be unset.
self.assert_only_network_limited_service(n1)
self.log.info("Check that UTXO-querying RPCs operate on snapshot chainstate")
snapshot_hash = loaded['tip_hash']
snapshot_num_coins = loaded['coins_loaded']
@ -491,6 +503,9 @@ class AssumeutxoTest(BitcoinTestFramework):
self.restart_node(1, extra_args=[
f"-stopatheight={PAUSE_HEIGHT}", *self.extra_args[1]])
# Upon restart during snapshot tip sync, the node must remain in 'limited' mode.
self.assert_only_network_limited_service(n1)
# Finally connect the nodes and let them sync.
#
# Set `wait_for_connect=False` to avoid a race between performing connection
@ -507,6 +522,9 @@ class AssumeutxoTest(BitcoinTestFramework):
self.log.info("Restarted node before snapshot validation completed, reloading...")
self.restart_node(1, extra_args=self.extra_args[1])
# Upon restart, the node must remain in 'limited' mode
self.assert_only_network_limited_service(n1)
# Send snapshot block to n1 out of order. This makes the test less
# realistic because normally the snapshot block is one of the last
# blocks downloaded, but its useful to test because it triggers more
@ -525,6 +543,10 @@ class AssumeutxoTest(BitcoinTestFramework):
self.log.info("Ensuring background validation completes")
self.wait_until(lambda: len(n1.getchainstates()['chainstates']) == 1)
# Since n1 is a pruned node, it will not signal NODE_NETWORK after
# completing the background sync.
self.assert_only_network_limited_service(n1)
# Ensure indexes have synced.
completed_idx_state = {
'basic block filter index': COMPLETE_IDX,
@ -555,12 +577,18 @@ class AssumeutxoTest(BitcoinTestFramework):
self.log.info("-- Testing all indexes + reindex")
assert_equal(n2.getblockcount(), START_HEIGHT)
assert 'NETWORK' in n2.getnetworkinfo()['localservicesnames'] # sanity check
self.log.info(f"Loading snapshot into third node from {dump_output['path']}")
loaded = n2.loadtxoutset(dump_output['path'])
assert_equal(loaded['coins_loaded'], SNAPSHOT_BASE_HEIGHT)
assert_equal(loaded['base_height'], SNAPSHOT_BASE_HEIGHT)
# Even though n2 is a full node, it will unset the 'NETWORK' service flag during snapshot loading.
# This indicates other peers that the node will temporarily not provide historical blocks.
self.log.info("Check node2 updated the local services during snapshot load")
self.assert_only_network_limited_service(n2)
for reindex_arg in ['-reindex=1', '-reindex-chainstate=1']:
self.log.info(f"Check that restarting with {reindex_arg} will delete the snapshot chainstate")
self.restart_node(2, extra_args=[reindex_arg, *self.extra_args[2]])
@ -584,6 +612,11 @@ class AssumeutxoTest(BitcoinTestFramework):
msg = "Unable to load UTXO snapshot: Can't activate a snapshot-based chainstate more than once"
assert_raises_rpc_error(-32603, msg, n2.loadtxoutset, dump_output['path'])
# Upon restart, the node must stay in 'limited' mode until the background
# chain sync completes.
self.restart_node(2, extra_args=self.extra_args[2])
self.assert_only_network_limited_service(n2)
self.connect_nodes(0, 2)
self.wait_until(lambda: n2.getchainstates()['chainstates'][-1]['blocks'] == FINAL_HEIGHT)
self.sync_blocks(nodes=(n0, n2))
@ -591,6 +624,9 @@ class AssumeutxoTest(BitcoinTestFramework):
self.log.info("Ensuring background validation completes")
self.wait_until(lambda: len(n2.getchainstates()['chainstates']) == 1)
# Once background chain sync completes, the full node must start offering historical blocks again.
assert {'NETWORK', 'NETWORK_LIMITED'}.issubset(n2.getnetworkinfo()['localservicesnames'])
completed_idx_state = {
'basic block filter index': COMPLETE_IDX,
'coinstatsindex': COMPLETE_IDX,