#!/usr/bin/env python3 # Copyright (c) 2014-2016 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 behavior of headers messages to announce blocks. Setup: - Two nodes: - node0 is the node-under-test. We create two p2p connections to it. The first p2p connection is a control and should only ever receive inv's. The second p2p connection tests the headers sending logic. - node1 is used to create reorgs. test_null_locators ================== Sends two getheaders requests with null locator values. First request's hashstop value refers to validated block, while second request's hashstop value refers to a block which hasn't been validated. Verifies only the first request returns headers. test_nonnull_locators ===================== Part 1: No headers announcements before "sendheaders" a. node mines a block [expect: inv] send getdata for the block [expect: block] b. node mines another block [expect: inv] send getheaders and getdata [expect: headers, then block] c. node mines another block [expect: inv] peer mines a block, announces with header [expect: getdata] d. node mines another block [expect: inv] Part 2: After "sendheaders", headers announcements should generally work. a. peer sends sendheaders [expect: no response] peer sends getheaders with current tip [expect: no response] b. node mines a block [expect: tip header] c. for N in 1, ..., 10: * for announce-type in {inv, header} - peer mines N blocks, announces with announce-type [ expect: getheaders/getdata or getdata, deliver block(s) ] - node mines a block [ expect: 1 header ] Part 3: Headers announcements stop after large reorg and resume after getheaders or inv from peer. - For response-type in {inv, getheaders} * node mines a 7 block reorg [ expect: headers announcement of 8 blocks ] * node mines an 8-block reorg [ expect: inv at tip ] * peer responds with getblocks/getdata [expect: inv, blocks ] * node mines another block [ expect: inv at tip, peer sends getdata, expect: block ] * node mines another block at tip [ expect: inv ] * peer responds with getheaders with an old hashstop more than 8 blocks back [expect: headers] * peer requests block [ expect: block ] * node mines another block at tip [ expect: inv, peer sends getdata, expect: block ] * peer sends response-type [expect headers if getheaders, getheaders/getdata if mining new block] * node mines 1 block [expect: 1 header, peer responds with getdata] Part 4: Test direct fetch behavior a. Announce 2 old block headers. Expect: no getdata requests. b. Announce 3 new blocks via 1 headers message. Expect: one getdata request for all 3 blocks. (Send blocks.) c. Announce 1 header that forks off the last two blocks. Expect: no response. d. Announce 1 more header that builds on that fork. Expect: one getdata request for two blocks. e. Announce 16 more headers that build on that fork. Expect: getdata request for 14 more blocks. f. Announce 1 more header that builds on that fork. Expect: no response. Part 5: Test handling of headers that don't connect. a. Repeat 10 times: 1. Announce a header that doesn't connect. Expect: getheaders message 2. Send headers chain. Expect: getdata for the missing blocks, tip update. b. Then send 9 more headers that don't connect. Expect: getheaders message each time. c. Announce a header that does connect. Expect: no response. d. Announce 49 headers that don't connect. Expect: getheaders message each time. e. Announce one more that doesn't connect. Expect: disconnect. """ from test_framework.blocktools import create_block, create_coinbase from test_framework.mininode import ( CBlockHeader, CInv, network_thread_start, P2PInterface, mininode_lock, msg_block, msg_getblocks, msg_getdata, msg_getheaders, msg_headers, msg_inv, msg_sendheaders, ) from test_framework.test_framework import BitcoinTestFramework from test_framework.util import ( assert_equal, sync_blocks, wait_until, ) DIRECT_FETCH_RESPONSE_TIME = 0.05 class BaseNode(P2PInterface): def __init__(self): super().__init__() self.block_announced = False self.last_blockhash_announced = None def send_get_data(self, block_hashes): """Request data for a list of block hashes.""" msg = msg_getdata() for x in block_hashes: msg.inv.append(CInv(2, x)) self.send_message(msg) def send_get_headers(self, locator, hashstop): msg = msg_getheaders() msg.locator.vHave = locator msg.hashstop = hashstop self.send_message(msg) def send_block_inv(self, blockhash): msg = msg_inv() msg.inv = [CInv(2, blockhash)] self.send_message(msg) def send_header_for_blocks(self, new_blocks): headers_message = msg_headers() headers_message.headers = [CBlockHeader(b) for b in new_blocks] self.send_message(headers_message) def send_getblocks(self, locator): getblocks_message = msg_getblocks() getblocks_message.locator.vHave = locator self.send_message(getblocks_message) def wait_for_getdata(self, hash_list, timeout=60): if hash_list == []: return test_function = lambda: "getdata" in self.last_message and [x.hash for x in self.last_message["getdata"].inv] == hash_list wait_until(test_function, timeout=timeout, lock=mininode_lock) def wait_for_block_announcement(self, block_hash, timeout=60): test_function = lambda: self.last_blockhash_announced == block_hash wait_until(test_function, timeout=timeout, lock=mininode_lock) def on_inv(self, message): self.block_announced = True self.last_blockhash_announced = message.inv[-1].hash def on_headers(self, message): if len(message.headers): self.block_announced = True message.headers[-1].calc_sha256() self.last_blockhash_announced = message.headers[-1].sha256 def clear_last_announcement(self): with mininode_lock: self.block_announced = False self.last_message.pop("inv", None) self.last_message.pop("headers", None) def check_last_announcement(self, headers=None, inv=None): """Test whether the last announcement received had the right header or the right inv. inv and headers should be lists of block hashes.""" test_function = lambda: self.block_announced wait_until(test_function, timeout=60, lock=mininode_lock) with mininode_lock: self.block_announced = False compare_inv = [] if "inv" in self.last_message: compare_inv = [x.hash for x in self.last_message["inv"].inv] if inv is not None: assert_equal(compare_inv, inv) compare_headers = [] if "headers" in self.last_message: compare_headers = [x.sha256 for x in self.last_message["headers"].headers] if headers is not None: assert_equal(compare_headers, headers) self.last_message.pop("inv", None) self.last_message.pop("headers", None) class SendHeadersTest(BitcoinTestFramework): def set_test_params(self): self.setup_clean_chain = True self.num_nodes = 2 def mine_blocks(self, count): """Mine count blocks and return the new tip.""" # Clear out last block announcement from each p2p listener [x.clear_last_announcement() for x in self.nodes[0].p2ps] self.nodes[0].generate(count) return int(self.nodes[0].getbestblockhash(), 16) def mine_reorg(self, length): """Mine a reorg that invalidates length blocks (replacing them with # length+1 blocks). Note: we clear the state of our p2p connections after the to-be-reorged-out blocks are mined, so that we don't break later tests. return the list of block hashes newly mined.""" self.nodes[0].generate(length) # make sure all invalidated blocks are node0's sync_blocks(self.nodes, wait=0.1) for x in self.nodes[0].p2ps: x.wait_for_block_announcement(int(self.nodes[0].getbestblockhash(), 16)) x.clear_last_announcement() tip_height = self.nodes[1].getblockcount() hash_to_invalidate = self.nodes[1].getblockhash(tip_height - (length - 1)) self.nodes[1].invalidateblock(hash_to_invalidate) all_hashes = self.nodes[1].generate(length + 1) # Must be longer than the orig chain sync_blocks(self.nodes, wait=0.1) return [int(x, 16) for x in all_hashes] def run_test(self): # Setup the p2p connections and start up the network thread. inv_node = self.nodes[0].add_p2p_connection(BaseNode()) # Make sure NODE_NETWORK is not set for test_node, so no block download # will occur outside of direct fetching test_node = self.nodes[0].add_p2p_connection(BaseNode(), services=0) network_thread_start() # Test logic begins here inv_node.wait_for_verack() test_node.wait_for_verack() # Ensure verack's have been processed by our peer inv_node.sync_with_ping() test_node.sync_with_ping() self.test_null_locators(test_node, inv_node) self.test_nonnull_locators(test_node, inv_node) def test_null_locators(self, test_node, inv_node): tip = self.nodes[0].getblockheader(self.nodes[0].generate(1)[0]) tip_hash = int(tip["hash"], 16) inv_node.check_last_announcement(inv=[tip_hash], headers=[]) test_node.check_last_announcement(inv=[tip_hash], headers=[]) self.log.info("Verify getheaders with null locator and valid hashstop returns headers.") test_node.clear_last_announcement() test_node.send_get_headers(locator=[], hashstop=tip_hash) test_node.check_last_announcement(headers=[tip_hash]) self.log.info("Verify getheaders with null locator and invalid hashstop does not return headers.") block = create_block(int(tip["hash"], 16), create_coinbase(tip["height"] + 1), tip["mediantime"] + 1) block.solve() test_node.send_header_for_blocks([block]) test_node.clear_last_announcement() test_node.send_get_headers(locator=[], hashstop=int(block.hash, 16)) test_node.sync_with_ping() assert_equal(test_node.block_announced, False) inv_node.clear_last_announcement() test_node.send_message(msg_block(block)) inv_node.check_last_announcement(inv=[int(block.hash, 16)], headers=[]) def test_nonnull_locators(self, test_node, inv_node): tip = int(self.nodes[0].getbestblockhash(), 16) # PART 1 # 1. Mine a block; expect inv announcements each time self.log.info("Part 1: headers don't start before sendheaders message...") for i in range(4): old_tip = tip tip = self.mine_blocks(1) inv_node.check_last_announcement(inv=[tip], headers=[]) test_node.check_last_announcement(inv=[tip], headers=[]) # Try a few different responses; none should affect next announcement if i == 0: # first request the block test_node.send_get_data([tip]) test_node.wait_for_block(tip) elif i == 1: # next try requesting header and block test_node.send_get_headers(locator=[old_tip], hashstop=tip) test_node.send_get_data([tip]) test_node.wait_for_block(tip) test_node.clear_last_announcement() # since we requested headers... elif i == 2: # this time announce own block via headers height = self.nodes[0].getblockcount() last_time = self.nodes[0].getblock(self.nodes[0].getbestblockhash())['time'] block_time = last_time + 1 new_block = create_block(tip, create_coinbase(height + 1), block_time) new_block.solve() test_node.send_header_for_blocks([new_block]) test_node.wait_for_getdata([new_block.sha256]) test_node.send_message(msg_block(new_block)) test_node.sync_with_ping() # make sure this block is processed inv_node.clear_last_announcement() test_node.clear_last_announcement() self.log.info("Part 1: success!") self.log.info("Part 2: announce blocks with headers after sendheaders message...") # PART 2 # 2. Send a sendheaders message and test that headers announcements # commence and keep working. test_node.send_message(msg_sendheaders()) prev_tip = int(self.nodes[0].getbestblockhash(), 16) test_node.send_get_headers(locator=[prev_tip], hashstop=0) test_node.sync_with_ping() # Now that we've synced headers, headers announcements should work tip = self.mine_blocks(1) inv_node.check_last_announcement(inv=[tip], headers=[]) test_node.check_last_announcement(headers=[tip]) height = self.nodes[0].getblockcount() + 1 block_time += 10 # Advance far enough ahead for i in range(10): # Mine i blocks, and alternate announcing either via # inv (of tip) or via headers. After each, new blocks # mined by the node should successfully be announced # with block header, even though the blocks are never requested for j in range(2): blocks = [] for b in range(i + 1): blocks.append(create_block(tip, create_coinbase(height), block_time)) blocks[-1].solve() tip = blocks[-1].sha256 block_time += 1 height += 1 if j == 0: # Announce via inv test_node.send_block_inv(tip) test_node.wait_for_getheaders() # Should have received a getheaders now test_node.send_header_for_blocks(blocks) # Test that duplicate inv's won't result in duplicate # getdata requests, or duplicate headers announcements [inv_node.send_block_inv(x.sha256) for x in blocks] test_node.wait_for_getdata([x.sha256 for x in blocks]) inv_node.sync_with_ping() else: # Announce via headers test_node.send_header_for_blocks(blocks) test_node.wait_for_getdata([x.sha256 for x in blocks]) # Test that duplicate headers won't result in duplicate # getdata requests (the check is further down) inv_node.send_header_for_blocks(blocks) inv_node.sync_with_ping() [test_node.send_message(msg_block(x)) for x in blocks] test_node.sync_with_ping() inv_node.sync_with_ping() # This block should not be announced to the inv node (since it also # broadcast it) assert "inv" not in inv_node.last_message assert "headers" not in inv_node.last_message tip = self.mine_blocks(1) inv_node.check_last_announcement(inv=[tip], headers=[]) test_node.check_last_announcement(headers=[tip]) height += 1 block_time += 1 self.log.info("Part 2: success!") self.log.info("Part 3: headers announcements can stop after large reorg, and resume after headers/inv from peer...") # PART 3. Headers announcements can stop after large reorg, and resume after # getheaders or inv from peer. for j in range(2): # First try mining a reorg that can propagate with header announcement new_block_hashes = self.mine_reorg(length=7) tip = new_block_hashes[-1] inv_node.check_last_announcement(inv=[tip], headers=[]) test_node.check_last_announcement(headers=new_block_hashes) block_time += 8 # Mine a too-large reorg, which should be announced with a single inv new_block_hashes = self.mine_reorg(length=8) tip = new_block_hashes[-1] inv_node.check_last_announcement(inv=[tip], headers=[]) test_node.check_last_announcement(inv=[tip], headers=[]) block_time += 9 fork_point = self.nodes[0].getblock("%02x" % new_block_hashes[0])["previousblockhash"] fork_point = int(fork_point, 16) # Use getblocks/getdata test_node.send_getblocks(locator=[fork_point]) test_node.check_last_announcement(inv=new_block_hashes, headers=[]) test_node.send_get_data(new_block_hashes) test_node.wait_for_block(new_block_hashes[-1]) for i in range(3): # Mine another block, still should get only an inv tip = self.mine_blocks(1) inv_node.check_last_announcement(inv=[tip], headers=[]) test_node.check_last_announcement(inv=[tip], headers=[]) if i == 0: # Just get the data -- shouldn't cause headers announcements to resume test_node.send_get_data([tip]) test_node.wait_for_block(tip) elif i == 1: # Send a getheaders message that shouldn't trigger headers announcements # to resume (best header sent will be too old) test_node.send_get_headers(locator=[fork_point], hashstop=new_block_hashes[1]) test_node.send_get_data([tip]) test_node.wait_for_block(tip) elif i == 2: test_node.send_get_data([tip]) test_node.wait_for_block(tip) # This time, try sending either a getheaders to trigger resumption # of headers announcements, or mine a new block and inv it, also # triggering resumption of headers announcements. if j == 0: test_node.send_get_headers(locator=[tip], hashstop=0) test_node.sync_with_ping() else: test_node.send_block_inv(tip) test_node.sync_with_ping() # New blocks should now be announced with header tip = self.mine_blocks(1) inv_node.check_last_announcement(inv=[tip], headers=[]) test_node.check_last_announcement(headers=[tip]) self.log.info("Part 3: success!") self.log.info("Part 4: Testing direct fetch behavior...") tip = self.mine_blocks(1) height = self.nodes[0].getblockcount() + 1 last_time = self.nodes[0].getblock(self.nodes[0].getbestblockhash())['time'] block_time = last_time + 1 # Create 2 blocks. Send the blocks, then send the headers. blocks = [] for b in range(2): blocks.append(create_block(tip, create_coinbase(height), block_time)) blocks[-1].solve() tip = blocks[-1].sha256 block_time += 1 height += 1 inv_node.send_message(msg_block(blocks[-1])) inv_node.sync_with_ping() # Make sure blocks are processed test_node.last_message.pop("getdata", None) test_node.send_header_for_blocks(blocks) test_node.sync_with_ping() # should not have received any getdata messages with mininode_lock: assert "getdata" not in test_node.last_message # This time, direct fetch should work blocks = [] for b in range(3): blocks.append(create_block(tip, create_coinbase(height), block_time)) blocks[-1].solve() tip = blocks[-1].sha256 block_time += 1 height += 1 test_node.send_header_for_blocks(blocks) test_node.sync_with_ping() test_node.wait_for_getdata([x.sha256 for x in blocks], timeout=DIRECT_FETCH_RESPONSE_TIME) [test_node.send_message(msg_block(x)) for x in blocks] test_node.sync_with_ping() # Now announce a header that forks the last two blocks tip = blocks[0].sha256 height -= 1 blocks = [] # Create extra blocks for later for b in range(20): blocks.append(create_block(tip, create_coinbase(height), block_time)) blocks[-1].solve() tip = blocks[-1].sha256 block_time += 1 height += 1 # Announcing one block on fork should not trigger direct fetch # (less work than tip) test_node.last_message.pop("getdata", None) test_node.send_header_for_blocks(blocks[0:1]) test_node.sync_with_ping() with mininode_lock: assert "getdata" not in test_node.last_message # Announcing one more block on fork should trigger direct fetch for # both blocks (same work as tip) test_node.send_header_for_blocks(blocks[1:2]) test_node.sync_with_ping() test_node.wait_for_getdata([x.sha256 for x in blocks[0:2]], timeout=DIRECT_FETCH_RESPONSE_TIME) # Announcing 16 more headers should trigger direct fetch for 14 more # blocks test_node.send_header_for_blocks(blocks[2:18]) test_node.sync_with_ping() test_node.wait_for_getdata([x.sha256 for x in blocks[2:16]], timeout=DIRECT_FETCH_RESPONSE_TIME) # Announcing 1 more header should not trigger any response test_node.last_message.pop("getdata", None) test_node.send_header_for_blocks(blocks[18:19]) test_node.sync_with_ping() with mininode_lock: assert "getdata" not in test_node.last_message self.log.info("Part 4: success!") # Now deliver all those blocks we announced. [test_node.send_message(msg_block(x)) for x in blocks] self.log.info("Part 5: Testing handling of unconnecting headers") # First we test that receipt of an unconnecting header doesn't prevent # chain sync. for i in range(10): test_node.last_message.pop("getdata", None) blocks = [] # Create two more blocks. for j in range(2): blocks.append(create_block(tip, create_coinbase(height), block_time)) blocks[-1].solve() tip = blocks[-1].sha256 block_time += 1 height += 1 # Send the header of the second block -> this won't connect. with mininode_lock: test_node.last_message.pop("getheaders", None) test_node.send_header_for_blocks([blocks[1]]) test_node.wait_for_getheaders() test_node.send_header_for_blocks(blocks) test_node.wait_for_getdata([x.sha256 for x in blocks]) [test_node.send_message(msg_block(x)) for x in blocks] test_node.sync_with_ping() assert_equal(int(self.nodes[0].getbestblockhash(), 16), blocks[1].sha256) blocks = [] # Now we test that if we repeatedly don't send connecting headers, we # don't go into an infinite loop trying to get them to connect. MAX_UNCONNECTING_HEADERS = 10 for j in range(MAX_UNCONNECTING_HEADERS + 1): blocks.append(create_block(tip, create_coinbase(height), block_time)) blocks[-1].solve() tip = blocks[-1].sha256 block_time += 1 height += 1 for i in range(1, MAX_UNCONNECTING_HEADERS): # Send a header that doesn't connect, check that we get a getheaders. with mininode_lock: test_node.last_message.pop("getheaders", None) test_node.send_header_for_blocks([blocks[i]]) test_node.wait_for_getheaders() # Next header will connect, should re-set our count: test_node.send_header_for_blocks([blocks[0]]) # Remove the first two entries (blocks[1] would connect): blocks = blocks[2:] # Now try to see how many unconnecting headers we can send # before we get disconnected. Should be 5*MAX_UNCONNECTING_HEADERS for i in range(5 * MAX_UNCONNECTING_HEADERS - 1): # Send a header that doesn't connect, check that we get a getheaders. with mininode_lock: test_node.last_message.pop("getheaders", None) test_node.send_header_for_blocks([blocks[i % len(blocks)]]) test_node.wait_for_getheaders() # Eventually this stops working. test_node.send_header_for_blocks([blocks[-1]]) # Should get disconnected test_node.wait_for_disconnect() self.log.info("Part 5: success!") # Finally, check that the inv node never received a getdata request, # throughout the test assert "getdata" not in inv_node.last_message if __name__ == '__main__': SendHeadersTest().main()