commit 7221fb3231a736dc5d3ebd5ed5e0723c9b8203f2
parent b3a2bce213451036ed49e4af4780ae2bbb90ac30
Author: SomberNight <somber.night@protonmail.com>
Date: Mon, 17 Sep 2018 22:21:55 +0200
interface: further simplifications for fork resolution
Diffstat:
2 files changed, 52 insertions(+), 59 deletions(-)
diff --git a/electrum/interface.py b/electrum/interface.py
@@ -448,6 +448,7 @@ class Interface(PrintError):
return await self._resolve_potential_chain_fork_given_forkpoint(good, bad, bad_header)
async def _search_headers_binary(self, height, bad, bad_header, chain):
+ assert bad == bad_header['block_height']
_assert_header_does_not_check_against_any_chain(bad_header)
self.blockchain = chain if isinstance(chain, Blockchain) else self.blockchain
@@ -467,7 +468,7 @@ class Interface(PrintError):
if good + 1 == bad:
break
- mock = bad_header and 'mock' in bad_header and bad_header['mock']['connect'](height)
+ mock = 'mock' in bad_header and bad_header['mock']['connect'](height)
real = not mock and self.blockchain.can_connect(bad_header, check_height=False)
if not real and not mock:
raise Exception('unexpected bad header during binary: {}'.format(bad_header))
@@ -478,39 +479,49 @@ class Interface(PrintError):
async def _resolve_potential_chain_fork_given_forkpoint(self, good, bad, bad_header):
assert good + 1 == bad
+ assert bad == bad_header['block_height']
_assert_header_does_not_check_against_any_chain(bad_header)
-
+ # 'good' is the height of a block 'good_header', somewhere in self.blockchain.
+ # bad_header connects to good_header; bad_header itself is NOT in self.blockchain.
+
+ bh = self.blockchain.height()
+ assert bh >= good
+ if bh == good:
+ height = good + 1
+ self.print_error("catching up from {}".format(height))
+ return 'no_fork', height
+
+ # this is a new fork we don't yet have
+ height = bad + 1
branch = blockchain.blockchains.get(bad)
if branch is not None:
- self.print_error("existing fork found at bad height {}".format(bad))
+ # Conflict!! As our fork handling is not completely general,
+ # we need to delete another fork to save this one.
+ # Note: This could be a potential DOS vector against Electrum.
+ # However, mining blocks that satisfy the difficulty requirements
+ # is assumed to be expensive; especially as forks below the max
+ # checkpoint are ignored.
+ self.print_error("new fork at bad height {}. conflict!!".format(bad))
ismocking = type(branch) is dict
- height = bad + 1
if ismocking:
self.print_error("TODO replace blockchain")
- return 'conflict', height
+ return 'fork_conflict', height
self.print_error('forkpoint conflicts with existing fork', branch.path())
branch.write(b'', 0)
branch.save_header(bad_header)
self.blockchain = branch
- return 'conflict', height
+ return 'fork_conflict', height
else:
- bh = self.blockchain.height()
- self.print_error("no existing fork yet at bad height {}. local chain height: {}".format(bad, bh))
- if bh > good:
- forkfun = self.blockchain.fork if 'mock' not in bad_header else bad_header['mock']['fork']
- b = forkfun(bad_header)
- with blockchain.blockchains_lock:
- assert bad not in blockchain.blockchains, (bad, list(blockchain.blockchains))
- blockchain.blockchains[bad] = b
- self.blockchain = b
- height = b.forkpoint + 1
- assert b.forkpoint == bad
- return 'fork', height
- else:
- assert bh == good
- self.print_error("catching up from %d" % (bh + 1))
- height = bh + 1
- return 'no_fork', height
+ # No conflict. Just save the new fork.
+ self.print_error("new fork at bad height {}. NO conflict.".format(bad))
+ forkfun = self.blockchain.fork if 'mock' not in bad_header else bad_header['mock']['fork']
+ b = forkfun(bad_header)
+ with blockchain.blockchains_lock:
+ assert bad not in blockchain.blockchains, (bad, list(blockchain.blockchains))
+ blockchain.blockchains[bad] = b
+ self.blockchain = b
+ assert b.forkpoint == bad
+ return 'fork_noconflict', height
async def _search_headers_backwards(self, height, header):
async def iterate():
diff --git a/electrum/tests/test_network.py b/electrum/tests/test_network.py
@@ -38,7 +38,7 @@ class TestNetwork(unittest.TestCase):
self.config = SimpleConfig({'electrum_path': tempfile.mkdtemp(prefix="test_network")})
self.interface = MockInterface(self.config)
- def test_new_fork(self):
+ def test_fork_noconflict(self):
blockchain.blockchains = {}
self.interface.q.put_nowait({'block_height': 8, 'mock': {'catchup':1, 'check': lambda x: False, 'connect': lambda x: False}})
def mock_connect(height):
@@ -49,10 +49,24 @@ class TestNetwork(unittest.TestCase):
self.interface.q.put_nowait({'block_height': 5, 'mock': {'binary':1,'check':lambda x: True, 'connect': lambda x: True}})
self.interface.q.put_nowait({'block_height': 6, 'mock': {'binary':1,'check':lambda x: True, 'connect': lambda x: True}})
ifa = self.interface
- self.assertEqual(('fork', 8), asyncio.get_event_loop().run_until_complete(ifa.sync_until(8, next_height=7)))
+ self.assertEqual(('fork_noconflict', 8), asyncio.get_event_loop().run_until_complete(ifa.sync_until(8, next_height=7)))
self.assertEqual(self.interface.q.qsize(), 0)
- def test_new_can_connect_during_backward(self):
+ def test_fork_conflict(self):
+ blockchain.blockchains = {7: {'check': lambda bad_header: False}}
+ self.interface.q.put_nowait({'block_height': 8, 'mock': {'catchup':1, 'check': lambda x: False, 'connect': lambda x: False}})
+ def mock_connect(height):
+ return height == 6
+ self.interface.q.put_nowait({'block_height': 7, 'mock': {'backward':1,'check': lambda x: False, 'connect': mock_connect, 'fork': self.mock_fork}})
+ self.interface.q.put_nowait({'block_height': 2, 'mock': {'backward':1,'check':lambda x: True, 'connect': lambda x: False}})
+ self.interface.q.put_nowait({'block_height': 4, 'mock': {'binary':1,'check':lambda x: True, 'connect': lambda x: True}})
+ self.interface.q.put_nowait({'block_height': 5, 'mock': {'binary':1,'check':lambda x: True, 'connect': lambda x: True}})
+ self.interface.q.put_nowait({'block_height': 6, 'mock': {'binary':1,'check':lambda x: True, 'connect': lambda x: True}})
+ ifa = self.interface
+ self.assertEqual(('fork_conflict', 8), asyncio.get_event_loop().run_until_complete(ifa.sync_until(8, next_height=7)))
+ self.assertEqual(self.interface.q.qsize(), 0)
+
+ def test_can_connect_during_backward(self):
blockchain.blockchains = {}
self.interface.q.put_nowait({'block_height': 8, 'mock': {'catchup':1, 'check': lambda x: False, 'connect': lambda x: False}})
def mock_connect(height):
@@ -68,7 +82,7 @@ class TestNetwork(unittest.TestCase):
def mock_fork(self, bad_header):
return blockchain.Blockchain(self.config, bad_header['block_height'], None)
- def test_new_chain_false_during_binary(self):
+ def test_chain_false_during_binary(self):
blockchain.blockchains = {}
self.interface.q.put_nowait({'block_height': 8, 'mock': {'catchup':1, 'check': lambda x: False, 'connect': lambda x: False}})
mock_connect = lambda height: height == 3
@@ -82,38 +96,6 @@ class TestNetwork(unittest.TestCase):
self.assertEqual(('catchup', 7), asyncio.get_event_loop().run_until_complete(ifa.sync_until(8, next_height=6)))
self.assertEqual(self.interface.q.qsize(), 0)
- @unittest.skip # FIXME test is broken
- def test_new_join(self):
- blockchain.blockchains = {7: {'check': lambda bad_header: True}}
- self.interface.q.put_nowait({'block_height': 8, 'mock': {'catchup':1, 'check': lambda x: False, 'connect': lambda x: False}})
- self.interface.q.put_nowait({'block_height': 7, 'mock': {'backward':1, 'check': lambda x: False, 'connect': lambda height: height == 6}})
- self.interface.q.put_nowait({'block_height': 2, 'mock': {'backward':1, 'check': lambda x: True, 'connect': lambda x: False}})
- self.interface.q.put_nowait({'block_height': 4, 'mock': {'binary':1, 'check': lambda x: True, 'connect': lambda x: False}})
- self.interface.q.put_nowait({'block_height': 5, 'mock': {'binary':1, 'check': lambda x: True, 'connect': lambda x: False}})
- self.interface.q.put_nowait({'block_height': 6, 'mock': {'binary':1, 'check': lambda x: True, 'connect': lambda x: True}})
- ifa = self.interface
- self.assertEqual(('join', 7), asyncio.get_event_loop().run_until_complete(ifa.sync_until(8, next_height=6)))
- self.assertEqual(self.interface.q.qsize(), 0)
-
- @unittest.skip # FIXME test is broken
- def test_new_reorg(self):
- times = 0
- def check(header):
- nonlocal times
- self.assertEqual(header['block_height'], 7)
- times += 1
- return False
- blockchain.blockchains = {7: {'check': check, 'parent': {'check': lambda x: True}}}
- self.interface.q.put_nowait({'block_height': 8, 'mock': {'catchup':1, 'check': lambda x: False, 'connect': lambda x: False}})
- self.interface.q.put_nowait({'block_height': 7, 'mock': {'backward':1, 'check': lambda x: False, 'connect': lambda height: height == 6}})
- self.interface.q.put_nowait({'block_height': 2, 'mock': {'backward':1, 'check': lambda x: 1, 'connect': lambda x: False}})
- self.interface.q.put_nowait({'block_height': 4, 'mock': {'binary':1, 'check': lambda x: 1, 'connect': lambda x: False}})
- self.interface.q.put_nowait({'block_height': 5, 'mock': {'binary':1, 'check': lambda x: 1, 'connect': lambda x: False}})
- self.interface.q.put_nowait({'block_height': 6, 'mock': {'binary':1, 'check': lambda x: 1, 'connect': lambda x: True}})
- ifa = self.interface
- self.assertEqual(('conflict', 8), asyncio.get_event_loop().run_until_complete(ifa.sync_until(8, next_height=7)))
- self.assertEqual(self.interface.q.qsize(), 0)
- self.assertEqual(times, 1)
if __name__=="__main__":
constants.set_regtest()
