#!/usr/bin/env python3
# Copyright (c) 2019-2021 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 (
NORMAL_GBT_REQUEST_PARAMS,
create_block,
)
from test_framework.util import assert_equal
NODE1_BLOCKS_REQUIRED = 15
NODE2_BLOCKS_REQUIRED = 2047
class RejectLowDifficultyHeadersTest(BitcoinTestFramework):
def set_test_params(self):
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 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)"]), self.nodes[2].assert_debug_log(expected_msgs=["[net] Ignoring low-work chain (height=14)"]), self.nodes[3].assert_debug_log(expected_msgs=["Synchronizing blockheaders, height: 14"]):
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(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(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)"]), self.nodes[3].assert_debug_log(expected_msgs=["Synchronizing blockheaders, height: 15"]):
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(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.sha256
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)
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.sync_blocks(timeout=300) # Ensure tips eventually agree
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().main()