1  #!/usr/bin/env python3
  2  # Copyright (c) 2019-present The Bitcoin Core developers
  3  # Distributed under the MIT software license, see the accompanying
  4  # file COPYING or http://www.opensource.org/licenses/mit-license.php.
  5  """Test that we reject low difficulty headers to prevent our block tree from filling up with useless bloat"""
  6  
  7  from test_framework.test_framework import BitcoinTestFramework
  8  
  9  from test_framework.p2p import (
 10      P2PInterface,
 11  )
 12  
 13  from test_framework.messages import (
 14      msg_headers,
 15  )
 16  
 17  from test_framework.blocktools import (
 18      NORMAL_GBT_REQUEST_PARAMS,
 19      create_block,
 20  )
 21  
 22  from test_framework.util import assert_equal
 23  
 24  import time
 25  
 26  NODE1_BLOCKS_REQUIRED = 15
 27  NODE2_BLOCKS_REQUIRED = 2047
 28  
 29  
 30  class RejectLowDifficultyHeadersTest(BitcoinTestFramework):
 31      def set_test_params(self):
 32          self.rpc_timeout *= 4  # To avoid timeout when generating BLOCKS_TO_MINE
 33          self.setup_clean_chain = True
 34          self.num_nodes = 4
 35          # Node0 has no required chainwork; node1 requires 15 blocks on top of the genesis block; node2 requires 2047
 36          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"]]
 37  
 38      def setup_network(self):
 39          self.setup_nodes()
 40          self.reconnect_all()
 41          self.sync_all()
 42  
 43      def disconnect_all(self):
 44          self.disconnect_nodes(0, 1)
 45          self.disconnect_nodes(0, 2)
 46          self.disconnect_nodes(0, 3)
 47  
 48      def reconnect_all(self):
 49          self.connect_nodes(0, 1)
 50          self.connect_nodes(0, 2)
 51          self.connect_nodes(0, 3)
 52  
 53      def mocktime_all(self, time):
 54          for n in self.nodes:
 55              n.setmocktime(time)
 56  
 57      def test_chains_sync_when_long_enough(self):
 58          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")
 59          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"]):
 60              self.generate(self.nodes[0], NODE1_BLOCKS_REQUIRED-1, sync_fun=self.no_op)
 61  
 62          # Node3 should always allow headers due to noban permissions
 63          self.log.info("Check that node3 will sync headers (due to noban permissions)")
 64  
 65          def check_node3_chaintips(num_tips, tip_hash, height):
 66              node3_chaintips = self.nodes[3].getchaintips()
 67              assert len(node3_chaintips) == num_tips
 68              assert {
 69                  'height': height,
 70                  'hash': tip_hash,
 71                  'branchlen': height,
 72                  'status': 'headers-only',
 73              } in node3_chaintips
 74  
 75          check_node3_chaintips(2, self.nodes[0].getbestblockhash(), NODE1_BLOCKS_REQUIRED-1)
 76  
 77          for node in self.nodes[1:3]:
 78              chaintips = node.getchaintips()
 79              assert len(chaintips) == 1
 80              assert {
 81                  'height': 0,
 82                  'hash': '0f9188f13cb7b2c71f2a335e3a4fc328bf5beb436012afca590b1a11466e2206',
 83                  'branchlen': 0,
 84                  'status': 'active',
 85              } in chaintips
 86  
 87          self.log.info("Generate more blocks to satisfy node1's minchainwork requirement, and verify node2 still has no new headers in headers tree")
 88          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"]):
 89              self.generate(self.nodes[0], NODE1_BLOCKS_REQUIRED - self.nodes[0].getblockcount(), sync_fun=self.no_op)
 90          self.sync_blocks(self.nodes[0:2]) # node3 will sync headers (noban permissions) but not blocks (due to minchainwork)
 91  
 92          assert {
 93              'height': 0,
 94              'hash': '0f9188f13cb7b2c71f2a335e3a4fc328bf5beb436012afca590b1a11466e2206',
 95              'branchlen': 0,
 96              'status': 'active',
 97          } in self.nodes[2].getchaintips()
 98  
 99          assert len(self.nodes[2].getchaintips()) == 1
100  
101          self.log.info("Check that node3 accepted these headers as well")
102          check_node3_chaintips(2, self.nodes[0].getbestblockhash(), NODE1_BLOCKS_REQUIRED)
103  
104          self.log.info("Generate long chain for node0/node1/node3")
105          self.generate(self.nodes[0], NODE2_BLOCKS_REQUIRED-self.nodes[0].getblockcount(), sync_fun=self.no_op)
106  
107          self.log.info("Verify that node2 and node3 will sync the chain when it gets long enough")
108          self.sync_blocks()
109  
110      def test_peerinfo_includes_headers_presync_height(self):
111          self.log.info("Test that getpeerinfo() includes headers presync height")
112  
113          # Disconnect network, so that we can find our own peer connection more
114          # easily
115          self.disconnect_all()
116  
117          p2p = self.nodes[0].add_p2p_connection(P2PInterface())
118          node = self.nodes[0]
119  
120          # Ensure we have a long chain already
121          current_height = self.nodes[0].getblockcount()
122          if (current_height < 3000):
123              self.generate(node, 3000-current_height, sync_fun=self.no_op)
124  
125          # Send a group of 2000 headers, forking from genesis.
126          new_blocks = []
127          hashPrevBlock = int(node.getblockhash(0), 16)
128          for i in range(2000):
129              block = create_block(hashprev = hashPrevBlock, tmpl=node.getblocktemplate(NORMAL_GBT_REQUEST_PARAMS))
130              block.solve()
131              new_blocks.append(block)
132              hashPrevBlock = block.hash_int
133  
134          headers_message = msg_headers(headers=new_blocks)
135          p2p.send_and_ping(headers_message)
136  
137          # getpeerinfo should show a sync in progress
138          assert_equal(node.getpeerinfo()[0]['presynced_headers'], 2000)
139  
140      def test_large_reorgs_can_succeed(self):
141          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")
142  
143          self.sync_all() # Ensure all nodes are synced.
144          self.disconnect_all()
145  
146          # locator(block at height T) will have heights:
147          # [T, T-1, ..., T-10, T-12, T-16, T-24, T-40, T-72, T-136, T-264,
148          #  T-520, T-1032, T-2056, T-4104, ...]
149          # So mine a number of blocks > 4104 to ensure that the first window of
150          # received headers during a sync are fully between locator entries.
151          BLOCKS_TO_MINE = 4110
152  
153          self.generate(self.nodes[0], BLOCKS_TO_MINE, sync_fun=self.no_op)
154          self.generate(self.nodes[1], BLOCKS_TO_MINE+2, sync_fun=self.no_op)
155  
156          self.reconnect_all()
157  
158          self.mocktime_all(int(time.time()))  # Temporarily hold time to avoid internal timeouts
159          self.sync_blocks(timeout=300) # Ensure tips eventually agree
160          self.mocktime_all(0)
161  
162  
163      def run_test(self):
164          self.test_chains_sync_when_long_enough()
165  
166          self.test_large_reorgs_can_succeed()
167  
168          self.test_peerinfo_includes_headers_presync_height()
169  
170  
171  
172  if __name__ == '__main__':
173      RejectLowDifficultyHeadersTest(__file__).main()