from bitcoin import *
-class BlockchainVerifier(threading.Thread):
- """ Simple Payment Verification """
+class Blockchain(threading.Thread):
- def __init__(self, interface, config):
+ def __init__(self, config, network):
threading.Thread.__init__(self)
self.daemon = True
self.config = config
- self.interface = interface
- self.interface.register_channel('verifier')
+ self.network = network
self.lock = threading.Lock()
- self.pending_headers = [] # headers that have not been verified
- self.height = 0
self.local_height = 0
self.running = False
self.headers_url = 'http://headers.electrum.org/blockchain_headers'
+ self.set_local_height()
+ self.queue = Queue.Queue()
+
+
+ def height(self):
+ return self.local_height
def stop(self):
with self.lock: self.running = False
- self.interface.poke('verifier')
+
def is_running(self):
with self.lock: return self.running
- def run(self):
+ def run(self):
self.init_headers_file()
self.set_local_height()
+ print_error( "blocks:", self.local_height )
with self.lock:
self.running = True
- requested_merkle = []
- requested_chunks = []
- requested_headers = []
- all_chunks = False
-
- # subscribe to block headers
- self.interface.send([ ('blockchain.headers.subscribe',[])], 'verifier')
while self.is_running():
- # request missing chunks
- if not all_chunks and self.height and not requested_chunks:
-
- if self.local_height + 50 < self.height:
- min_index = (self.local_height + 1)/2016
- max_index = (self.height + 1)/2016
- for i in range(min_index, max_index + 1):
- print_error( "requesting chunk", i )
- self.interface.send([ ('blockchain.block.get_chunk',[i])], 'verifier')
- requested_chunks.append(i)
- break
- else:
- all_chunks = True
- print_error("downloaded all chunks")
-
-
- # process pending headers
- if self.pending_headers and all_chunks:
- done = []
- for header in self.pending_headers:
- if self.verify_header(header):
- done.append(header)
- else:
- # request previous header
- i = header.get('block_height') - 1
- if i not in requested_headers:
- print_error("requesting header %d"%i)
- self.interface.send([ ('blockchain.block.get_header',[i])], 'verifier')
- requested_headers.append(i)
- # no point continuing
- break
- if done:
- self.interface.trigger_callback('updated')
- for header in done:
- self.pending_headers.remove(header)
try:
- r = self.interface.get_response('verifier',timeout=1)
+ result = self.queue.get()
except Queue.Empty:
continue
- if not r: continue
- if r.get('error'):
- print_error('Verifier received an error:', r)
- continue
+ if not result: continue
- # 3. handle response
- method = r['method']
- params = r['params']
- result = r['result']
+ i, header = result
+ if not header: continue
+
+ height = header.get('block_height')
- if method == 'blockchain.block.get_chunk':
- index = params[0]
- self.verify_chunk(index, result)
- requested_chunks.remove(index)
+ if height <= self.local_height:
+ continue
- elif method in ['blockchain.headers.subscribe', 'blockchain.block.get_header']:
+ if height > self.local_height + 50:
+ if not self.get_and_verify_chunks(i, header, height):
+ continue
- self.pending_headers.append(result)
- if method == 'blockchain.block.get_header':
- requested_headers.remove(result.get('block_height'))
- else:
- self.height = result.get('block_height')
- ## fixme # self.interface.poke('synchronizer')
+ if height > self.local_height:
+ # get missing parts from interface (until it connects to my chain)
+ chain = self.get_chain( i, header )
+
+ # skip that server if the result is not consistent
+ if not chain:
+ print_error('e')
+ continue
- self.pending_headers.sort(key=lambda x: x.get('block_height'))
- # print "pending headers", map(lambda x: x.get('block_height'), self.pending_headers)
+ # verify the chain
+ if self.verify_chain( chain ):
+ print_error("height:", height, i.server)
+ for header in chain:
+ self.save_header(header)
+ else:
+ print_error("error", i.server)
+ # todo: dismiss that server
+ continue
+
+ self.network.new_blockchain_height(height, i)
+
+
+ def verify_chain(self, chain):
+
+ first_header = chain[0]
+ prev_header = self.read_header(first_header.get('block_height') -1)
+
+ for header in chain:
+
+ height = header.get('block_height')
+
+ prev_hash = self.hash_header(prev_header)
+ bits, target = self.get_target(height/2016, chain)
+ _hash = self.hash_header(header)
+ try:
+ assert prev_hash == header.get('prev_block_hash')
+ assert bits == header.get('bits')
+ assert int('0x'+_hash,16) < target
+ except Exception:
+ return False
+
+ prev_header = header
+
+ return True
+
def verify_chunk(self, index, hexdata):
data = hexdata.decode('hex')
height = index*2016
num = len(data)/80
- print_error("validating headers %d"%height)
if index == 0:
previous_hash = ("0"*64)
_hash = self.hash_header(header)
assert previous_hash == header.get('prev_block_hash')
assert bits == header.get('bits')
- assert eval('0x'+_hash) < target
+ assert int('0x'+_hash,16) < target
previous_header = header
previous_hash = _hash
self.save_chunk(index, data)
+ print_error("validated chunk %d"%height)
-
- def verify_header(self, header):
- # add header to the blockchain file
- # if there is a reorg, push it in a stack
-
- height = header.get('block_height')
-
- prev_header = self.read_header(height -1)
- if not prev_header:
- # return False to request previous header
- return False
-
- prev_hash = self.hash_header(prev_header)
- bits, target = self.get_target(height/2016)
- _hash = self.hash_header(header)
- try:
- assert prev_hash == header.get('prev_block_hash')
- assert bits == header.get('bits')
- assert eval('0x'+_hash) < target
- except:
- # this can be caused by a reorg.
- print_error("verify header failed"+ repr(header))
- # undo verifications
- with self.lock:
- items = self.verified_tx.items()[:]
- for tx_hash, item in items:
- tx_height, timestamp, pos = item
- if tx_height >= height:
- print_error("redoing", tx_hash)
- with self.lock:
- self.verified_tx.pop(tx_hash)
- if tx_hash in self.merkle_roots:
- self.merkle_roots.pop(tx_hash)
- # return False to request previous header.
- return False
-
- self.save_header(header)
- print_error("verify header:", _hash, height)
- return True
-
-
def header_to_string(self, res):
s = int_to_hex(res.get('version'),4) \
+ rev_hex(res.get('prev_block_hash')) \
def header_from_string(self, s):
- hex_to_int = lambda s: eval('0x' + s[::-1].encode('hex'))
+ hex_to_int = lambda s: int('0x' + s[::-1].encode('hex'), 16)
h = {}
h['version'] = hex_to_int(s[0:4])
h['prev_block_hash'] = hash_encode(s[4:36])
return rev_hex(Hash(self.header_to_string(header).decode('hex')).encode('hex'))
def path(self):
- wdir = self.config.get('blockchain_headers_path', user_dir())
- if wdir and not os.path.exists( wdir ): os.mkdir(wdir)
- return os.path.join( wdir, 'blockchain_headers')
+ return os.path.join( self.config.path, 'blockchain_headers')
def init_headers_file(self):
filename = self.path()
socket.setdefaulttimeout(30)
print_error("downloading ", self.headers_url )
urllib.urlretrieve(self.headers_url, filename)
- except:
+ print_error("done.")
+ except Exception:
print_error( "download failed. creating file", filename )
open(filename,'wb+').close()
return h
- def get_target(self, index):
+ def get_target(self, index, chain=None):
+ if chain is None:
+ chain = [] # Do not use mutables as default values!
max_target = 0x00000000FFFF0000000000000000000000000000000000000000000000000000
if index == 0: return 0x1d00ffff, max_target
first = self.read_header((index-1)*2016)
last = self.read_header(index*2016-1)
-
+ if last is None:
+ for h in chain:
+ if h.get('block_height') == index*2016-1:
+ last = h
+
nActualTimespan = last.get('timestamp') - first.get('timestamp')
nTargetTimespan = 14*24*60*60
nActualTimespan = max(nActualTimespan, nTargetTimespan/4)
c = c[2:]
i -= 1
- c = eval('0x'+c[0:6])
- if c > 0x800000:
+ c = int('0x'+c[0:6],16)
+ if c >= 0x800000:
c /= 256
i += 1
new_bits = c + MM * i
return new_bits, new_target
+
+ def request_header(self, i, h, queue):
+ print_error("requesting header %d from %s"%(h, i.server))
+ i.send([ ('blockchain.block.get_header',[h])], lambda i,r: queue.put((i,r)))
+
+ def retrieve_header(self, i, queue):
+ while True:
+ try:
+ ir = queue.get(timeout=1)
+ except Queue.Empty:
+ print_error('timeout')
+ continue
+
+ if not ir:
+ continue
+
+ i, r = ir
+
+ if r.get('error'):
+ print_error('Verifier received an error:', r)
+ continue
+
+ # 3. handle response
+ method = r['method']
+ params = r['params']
+ result = r['result']
+
+ if method == 'blockchain.block.get_header':
+ return result
+
+
+
+ def get_chain(self, interface, final_header):
+
+ header = final_header
+ chain = [ final_header ]
+ requested_header = False
+ queue = Queue.Queue()
+
+ while self.is_running():
+
+ if requested_header:
+ header = self.retrieve_header(interface, queue)
+ if not header: return
+ chain = [ header ] + chain
+ requested_header = False
+
+ height = header.get('block_height')
+ previous_header = self.read_header(height -1)
+ if not previous_header:
+ self.request_header(interface, height - 1, queue)
+ requested_header = True
+ continue
+
+ # verify that it connects to my chain
+ prev_hash = self.hash_header(previous_header)
+ if prev_hash != header.get('prev_block_hash'):
+ print_error("reorg")
+ self.request_header(interface, height - 1, queue)
+ requested_header = True
+ continue
+
+ else:
+ # the chain is complete
+ return chain
+
+
+ def get_and_verify_chunks(self, i, header, height):
+
+ queue = Queue.Queue()
+ min_index = (self.local_height + 1)/2016
+ max_index = (height + 1)/2016
+ n = min_index
+ while n < max_index + 1:
+ print_error( "Requesting chunk:", n )
+ r = i.synchronous_get([ ('blockchain.block.get_chunk',[n])])[0]
+ if not r:
+ continue
+ try:
+ self.verify_chunk(n, r)
+ n = n + 1
+ except Exception:
+ print_error('Verify chunk failed!')
+ n = n - 1
+ if n < 0:
+ return False
+
+ return True
+
git://git.novaco.in / electrum-nvc.git / blobdiff