Files
bitcoin/test/functional/p2p_headers_sync_with_minchainwork.py
Hodlinator ff3e2e4ebd net: Trigger process abort when behind start block MTP
We should not proceed syncing headers from peers when the local system clock is incorrectly set.

A node with a system clock set too far back will typically fail early during startup when the chainstate detects the tip to be too far in the future. This means that in practice we don't expect the failure to ever happen in net_processing.cpp.

An exception is thrown from HeadersSyncState() in order to only compute the error condition once. An alternative would be to compute it a second time in TryLowWorkHeadersSync() to guard against calling HeadersSyncState(), and have an assert inside HeadersSyncState(). We shut down the process so possible resource leaks due to the exception should not be an issue, although none have been spotted. Throwing an exception also keeps the unit test straightforward.

Co-authored-by: Lőrinc <pap.lorinc@gmail.com>
2026-08-19 13:01:14 +02:00

193 lines
7.9 KiB
Python
Executable File

#!/usr/bin/env python3
# Copyright (c) 2019-present The Bitcoin Core developers
# Distributed under the MIT software license, see the accompanying
# file COPYING or http://www.opensource.org/licenses/mit-license.php.
"""Test that we reject low difficulty headers to prevent our block tree from filling up with useless bloat"""
from test_framework.test_framework import BitcoinTestFramework
from test_framework.p2p import (
P2PInterface,
)
from test_framework.messages import (
msg_headers,
)
from test_framework.blocktools import (
MAX_FUTURE_BLOCK_TIME,
NORMAL_GBT_REQUEST_PARAMS,
create_block,
)
from test_framework.util import assert_equal
import re
import time
NODE1_BLOCKS_REQUIRED = 15
NODE2_BLOCKS_REQUIRED = 2047
class RejectLowDifficultyHeadersTest(BitcoinTestFramework):
def set_test_params(self):
self.rpc_timeout *= 4 # To avoid timeout when generating BLOCKS_TO_MINE
self.setup_clean_chain = True
self.num_nodes = 4
# Node0 has no required chainwork; node1 requires 15 blocks on top of the genesis block; node2 requires 2047
self.extra_args = [["-minimumchainwork=0x0", "-checkblockindex=0"], ["-minimumchainwork=0x1f", "-checkblockindex=0"], ["-minimumchainwork=0x1000", "-checkblockindex=0"], ["-minimumchainwork=0x1000", "-checkblockindex=0", "-whitelist=noban@127.0.0.1"]]
def setup_network(self):
self.setup_nodes()
self.reconnect_all()
self.sync_all()
def disconnect_all(self):
self.disconnect_nodes(0, 1)
self.disconnect_nodes(0, 2)
self.disconnect_nodes(0, 3)
def reconnect_all(self):
self.connect_nodes(0, 1)
self.connect_nodes(0, 2)
self.connect_nodes(0, 3)
def mocktime_all(self, time):
for n in self.nodes:
n.setmocktime(time)
def test_chains_sync_when_long_enough(self):
self.log.info("Generate blocks on the node with no required chainwork, and verify nodes 1 and 2 have no new headers in their headers tree")
with (
self.nodes[1].assert_debug_log(expected_msgs=["[net] Ignoring low-work chain (height=14)"], timeout=2),
self.nodes[2].assert_debug_log(expected_msgs=["[net] Ignoring low-work chain (height=14)"], timeout=2),
self.nodes[3].assert_debug_log(expected_msgs=["Synchronizing blockheaders, height: 14"], timeout=2),
):
self.generate(self.nodes[0], NODE1_BLOCKS_REQUIRED-1, sync_fun=self.no_op)
# Node3 should always allow headers due to noban permissions
self.log.info("Check that node3 will sync headers (due to noban permissions)")
def check_node3_chaintips(num_tips, tip_hash, height):
node3_chaintips = self.nodes[3].getchaintips()
assert_equal(len(node3_chaintips), num_tips)
assert {
'height': height,
'hash': tip_hash,
'branchlen': height,
'status': 'headers-only',
} in node3_chaintips
check_node3_chaintips(2, self.nodes[0].getbestblockhash(), NODE1_BLOCKS_REQUIRED-1)
for node in self.nodes[1:3]:
chaintips = node.getchaintips()
assert_equal(len(chaintips), 1)
assert {
'height': 0,
'hash': '0f9188f13cb7b2c71f2a335e3a4fc328bf5beb436012afca590b1a11466e2206',
'branchlen': 0,
'status': 'active',
} in chaintips
self.log.info("Generate more blocks to satisfy node1's minchainwork requirement, and verify node2 still has no new headers in headers tree")
with (
self.nodes[2].assert_debug_log(expected_msgs=["[net] Ignoring low-work chain (height=15)"], timeout=2),
self.nodes[3].assert_debug_log(expected_msgs=["Synchronizing blockheaders, height: 15"], timeout=2),
):
self.generate(self.nodes[0], NODE1_BLOCKS_REQUIRED - self.nodes[0].getblockcount(), sync_fun=self.no_op)
self.sync_blocks(self.nodes[0:2]) # node3 will sync headers (noban permissions) but not blocks (due to minchainwork)
assert {
'height': 0,
'hash': '0f9188f13cb7b2c71f2a335e3a4fc328bf5beb436012afca590b1a11466e2206',
'branchlen': 0,
'status': 'active',
} in self.nodes[2].getchaintips()
assert_equal(len(self.nodes[2].getchaintips()), 1)
self.log.info("Check that node3 accepted these headers as well")
check_node3_chaintips(2, self.nodes[0].getbestblockhash(), NODE1_BLOCKS_REQUIRED)
self.log.info("Generate long chain for node0/node1/node3")
self.generate(self.nodes[0], NODE2_BLOCKS_REQUIRED-self.nodes[0].getblockcount(), sync_fun=self.no_op)
self.log.info("Verify that node2 and node3 will sync the chain when it gets long enough")
self.sync_blocks()
def test_peerinfo_includes_headers_presync_height(self):
self.log.info("Test that getpeerinfo() includes headers presync height")
# Disconnect network, so that we can find our own peer connection more
# easily
self.disconnect_all()
p2p = self.nodes[0].add_p2p_connection(P2PInterface())
node = self.nodes[0]
# Ensure we have a long chain already
current_height = self.nodes[0].getblockcount()
if (current_height < 3000):
self.generate(node, 3000-current_height, sync_fun=self.no_op)
# Send a group of 2000 headers, forking from genesis.
new_blocks = []
hashPrevBlock = int(node.getblockhash(0), 16)
for i in range(2000):
block = create_block(hashprev = hashPrevBlock, tmpl=node.getblocktemplate(NORMAL_GBT_REQUEST_PARAMS))
block.solve()
new_blocks.append(block)
hashPrevBlock = block.hash_int
headers_message = msg_headers(headers=new_blocks)
p2p.send_and_ping(headers_message)
# getpeerinfo should show a sync in progress
assert_equal(node.getpeerinfo()[0]['presynced_headers'], 2000)
self.log.info("Test whether a lagging clock aborts low-work headers sync")
node.disconnect_p2ps()
node.setmocktime(node.getblockheader(node.getblockhash(0))['mediantime'] - MAX_FUTURE_BLOCK_TIME - 1)
p2p = node.add_p2p_connection(P2PInterface())
p2p.send_without_ping(headers_message)
node.wait_until_stopped(expect_error=True, expected_ret_code=[-6, # Unix
3, # Windows native
0xC0000409], # Windows cross builds
expected_stderr=re.compile("Failure when attempting to initiate headers sync: System clock"))
def test_large_reorgs_can_succeed(self):
self.log.info("Test that a 2000+ block reorg, starting from a point that is more than 2000 blocks before a locator entry, can succeed")
self.sync_all() # Ensure all nodes are synced.
self.disconnect_all()
# locator(block at height T) will have heights:
# [T, T-1, ..., T-10, T-12, T-16, T-24, T-40, T-72, T-136, T-264,
# T-520, T-1032, T-2056, T-4104, ...]
# So mine a number of blocks > 4104 to ensure that the first window of
# received headers during a sync are fully between locator entries.
BLOCKS_TO_MINE = 4110
self.generate(self.nodes[0], BLOCKS_TO_MINE, sync_fun=self.no_op)
self.generate(self.nodes[1], BLOCKS_TO_MINE+2, sync_fun=self.no_op)
self.reconnect_all()
self.mocktime_all(int(time.time())) # Temporarily hold time to avoid internal timeouts
self.sync_blocks(timeout=300) # Ensure tips eventually agree
self.mocktime_all(0)
def run_test(self):
self.test_chains_sync_when_long_enough()
self.test_large_reorgs_can_succeed()
self.test_peerinfo_includes_headers_presync_height()
if __name__ == '__main__':
RejectLowDifficultyHeadersTest(__file__).main()