#!/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()