Inside Bitcoin

1#!/usr/bin/env python3
2# Copyright (c) 2022-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"""
6Test stalling logic during IBD
7"""
8
9import time
10
11from test_framework.blocktools import (
12        create_block,
13)
14from test_framework.messages import (
15        MSG_BLOCK,
16        MSG_TYPE_MASK,
17)
18from test_framework.p2p import (
19        CBlockHeader,
20        msg_block,
21        msg_headers,
22        P2PDataStore,
23)
24from test_framework.test_framework import BitcoinTestFramework
25from test_framework.util import (
26        assert_equal,
27)
28
29
30class P2PStaller(P2PDataStore):
31    def __init__(self, stall_blocks):
32        self.stall_blocks = stall_blocks
33        super().__init__()
34
35    def on_getdata(self, message):
36        for inv in message.inv:
37            self.getdata_requests.append(inv.hash)
38            if (inv.type & MSG_TYPE_MASK) == MSG_BLOCK:
39                if (inv.hash not in self.stall_blocks):
40                    self.send_without_ping(msg_block(self.block_store[inv.hash]))
41
42    def on_getheaders(self, message):
43        pass
44
45
46class P2PIBDStallingTest(BitcoinTestFramework):
47    def set_test_params(self):
48        self.setup_clean_chain = True
49        self.num_nodes = 1
50
51    def run_test(self):
52        NUM_BLOCKS = 1025
53        NUM_PEERS = 5
54        node = self.nodes[0]
55        tip = int(node.getbestblockhash(), 16)
56        blocks = []
57        height = 1
58        block_time = node.getblock(node.getbestblockhash())['time'] + 1
59        self.log.info("Prepare blocks without sending them to the node")
60        block_dict = {}
61        for _ in range(NUM_BLOCKS):
62            blocks.append(create_block(tip, height=height, ntime=block_time))
63            blocks[-1].solve()
64            tip = blocks[-1].hash_int
65            block_time += 1
66            height += 1
67            block_dict[blocks[-1].hash_int] = blocks[-1]
68        stall_index = 0
69        second_stall_index = 500
70        stall_blocks = [blocks[stall_index].hash_int, blocks[second_stall_index].hash_int]
71
72        headers_message = msg_headers()
73        headers_message.headers = [CBlockHeader(b) for b in blocks[:NUM_BLOCKS-1]]
74        peers = []
75
76        self.log.info("Check that a staller does not get disconnected if the 1024 block lookahead buffer is filled")
77        self.mocktime = int(time.time()) + 1
78        node.setmocktime(self.mocktime)
79        for id in range(NUM_PEERS):
80            peers.append(node.add_outbound_p2p_connection(P2PStaller(stall_blocks), p2p_idx=id, connection_type="outbound-full-relay"))
81            peers[-1].block_store = block_dict
82            peers[-1].send_and_ping(headers_message)
83
84        # Wait until all blocks are received (except for the stall blocks), so that no other blocks are in flight.
85        self.wait_until(lambda: sum(len(peer['inflight']) for peer in node.getpeerinfo()) == len(stall_blocks))
86
87        self.all_sync_send_with_ping(peers)
88        # If there was a peer marked for stalling, it would get disconnected
89        self.mocktime += 3
90        node.setmocktime(self.mocktime)
91        self.all_sync_send_with_ping(peers)
92        assert_equal(node.num_test_p2p_connections(), NUM_PEERS)
93
94        self.log.info("Check that increasing the window beyond 1024 blocks triggers stalling logic")
95        headers_message.headers = [CBlockHeader(b) for b in blocks]
96        with node.assert_debug_log(expected_msgs=['Stall started']):
97            for p in peers:
98                p.send_without_ping(headers_message)
99            self.all_sync_send_with_ping(peers)
100
101        self.log.info("Check that the stalling peer is disconnected after 2 seconds")
102        self.mocktime += 3
103        node.setmocktime(self.mocktime)
104        peers[0].wait_for_disconnect()
105        assert_equal(node.num_test_p2p_connections(), NUM_PEERS - 1)
106        self.wait_until(lambda: self.is_block_requested(peers, stall_blocks[0]))
107        # Make sure that SendMessages() is invoked, which assigns the missing block
108        # to another peer and starts the stalling logic for them
109        self.all_sync_send_with_ping(peers)
110
111        self.log.info("Check that the stalling timeout gets doubled to 4 seconds for the next staller")
112        # No disconnect after just 3 seconds
113        self.mocktime += 3
114        node.setmocktime(self.mocktime)
115        self.all_sync_send_with_ping(peers)
116        assert_equal(node.num_test_p2p_connections(), NUM_PEERS - 1)
117
118        self.mocktime += 2
119        node.setmocktime(self.mocktime)
120        self.wait_until(lambda: sum(x.is_connected for x in node.p2ps) == NUM_PEERS - 2)
121        self.wait_until(lambda: self.is_block_requested(peers, stall_blocks[0]))
122        self.all_sync_send_with_ping(peers)
123
124        self.log.info("Check that the stalling timeout gets doubled to 8 seconds for the next staller")
125        # No disconnect after just 7 seconds
126        self.mocktime += 7
127        node.setmocktime(self.mocktime)
128        self.all_sync_send_with_ping(peers)
129        assert_equal(node.num_test_p2p_connections(), NUM_PEERS - 2)
130
131        self.mocktime += 2
132        node.setmocktime(self.mocktime)
133        self.wait_until(lambda: sum(x.is_connected for x in node.p2ps) == NUM_PEERS - 3)
134        self.wait_until(lambda: self.is_block_requested(peers, stall_blocks[0]))
135        self.all_sync_send_with_ping(peers)
136
137        self.log.info("Provide the first withheld block and check that stalling timeout gets reduced back to 2 seconds")
138        with node.assert_debug_log(expected_msgs=['Decreased stalling timeout to 2 seconds'], unexpected_msgs=['Stall started']):
139            for p in peers:
140                if p.is_connected and (stall_blocks[0] in p.getdata_requests):
141                    p.send_without_ping(msg_block(block_dict[stall_blocks[0]]))
142            self.all_sync_send_with_ping(peers)
143
144        self.log.info("Check that all outstanding blocks up to the second stall block get connected")
145        self.wait_until(lambda: node.getblockcount() == second_stall_index)
146
147
148    def all_sync_send_with_ping(self, peers):
149        for p in peers:
150            if p.is_connected:
151                p.sync_with_ping()
152
153    def is_block_requested(self, peers, hash):
154        for p in peers:
155            if p.is_connected and (hash in p.getdata_requests):
156                return True
157        return False
158
159
160if __name__ == '__main__':
161    P2PIBDStallingTest(__file__).main()
162