420 lines
12 KiB
Python
420 lines
12 KiB
Python
#!/usr/bin/env python
|
|
#
|
|
# Electrum - lightweight Bitcoin client
|
|
# Copyright (C) 2012 thomasv@ecdsa.org
|
|
#
|
|
# This program is free software: you can redistribute it and/or modify
|
|
# it under the terms of the GNU General Public License as published by
|
|
# the Free Software Foundation, either version 3 of the License, or
|
|
# (at your option) any later version.
|
|
#
|
|
# This program is distributed in the hope that it will be useful,
|
|
# but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
# GNU General Public License for more details.
|
|
#
|
|
# You should have received a copy of the GNU General Public License
|
|
# along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
|
|
import threading, time, Queue, os, sys, shutil
|
|
from util import user_dir, appdata_dir, print_error
|
|
from bitcoin import *
|
|
|
|
|
|
class Blockchain(threading.Thread):
|
|
|
|
def __init__(self, config, network):
|
|
threading.Thread.__init__(self)
|
|
self.daemon = True
|
|
self.config = config
|
|
self.network = network
|
|
self.lock = threading.Lock()
|
|
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()
|
|
self.servers_height = {}
|
|
self.is_lagging = False
|
|
|
|
|
|
def stop(self):
|
|
with self.lock: self.running = False
|
|
|
|
|
|
def is_running(self):
|
|
with self.lock: return self.running
|
|
|
|
|
|
def run(self):
|
|
self.init_headers_file()
|
|
self.set_local_height()
|
|
print_error( "blocks:", self.local_height )
|
|
|
|
with self.lock:
|
|
self.running = True
|
|
|
|
while self.is_running():
|
|
|
|
try:
|
|
result = self.queue.get()
|
|
except Queue.Empty:
|
|
continue
|
|
|
|
if not result: continue
|
|
|
|
i, header = result
|
|
if not header: continue
|
|
|
|
height = header.get('block_height')
|
|
self.servers_height[i.server] = height
|
|
|
|
if height > self.local_height + 50:
|
|
self.get_chunks(i, header, height)
|
|
self.network.trigger_callback('updated')
|
|
|
|
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: continue
|
|
|
|
# verify the chain
|
|
if self.verify_chain( chain ):
|
|
print_error("height:", height, i.server)
|
|
for header in chain:
|
|
self.save_header(header)
|
|
self.height = height
|
|
else:
|
|
print_error("error", i.server)
|
|
# todo: dismiss that server
|
|
|
|
h = self.servers_height.get(self.network.interface.server)
|
|
if h is not None and h < height - 1:
|
|
print_error( "Server is lagging", height, h)
|
|
if self.config.get('auto_cycle'):
|
|
self.network.set_server(i.server)
|
|
else:
|
|
self.network.is_lagging = True
|
|
else:
|
|
self.network.is_lagging = False
|
|
|
|
self.network.trigger_callback('updated')
|
|
|
|
|
|
|
|
|
|
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)
|
|
_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:
|
|
return False
|
|
|
|
prev_header = header
|
|
|
|
return True
|
|
|
|
|
|
|
|
def verify_chunk(self, index, hexdata):
|
|
data = hexdata.decode('hex')
|
|
height = index*2016
|
|
num = len(data)/80
|
|
|
|
if index == 0:
|
|
previous_hash = ("0"*64)
|
|
else:
|
|
prev_header = self.read_header(index*2016-1)
|
|
if prev_header is None: raise
|
|
previous_hash = self.hash_header(prev_header)
|
|
|
|
bits, target = self.get_target(index)
|
|
|
|
for i in range(num):
|
|
height = index*2016 + i
|
|
raw_header = data[i*80:(i+1)*80]
|
|
header = self.header_from_string(raw_header)
|
|
_hash = self.hash_header(header)
|
|
assert previous_hash == header.get('prev_block_hash')
|
|
assert bits == header.get('bits')
|
|
assert eval('0x'+_hash) < 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))
|
|
verifier.undo_verifications()
|
|
|
|
# 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')) \
|
|
+ rev_hex(res.get('merkle_root')) \
|
|
+ int_to_hex(int(res.get('timestamp')),4) \
|
|
+ int_to_hex(int(res.get('bits')),4) \
|
|
+ int_to_hex(int(res.get('nonce')),4)
|
|
return s
|
|
|
|
|
|
def header_from_string(self, s):
|
|
hex_to_int = lambda s: eval('0x' + s[::-1].encode('hex'))
|
|
h = {}
|
|
h['version'] = hex_to_int(s[0:4])
|
|
h['prev_block_hash'] = hash_encode(s[4:36])
|
|
h['merkle_root'] = hash_encode(s[36:68])
|
|
h['timestamp'] = hex_to_int(s[68:72])
|
|
h['bits'] = hex_to_int(s[72:76])
|
|
h['nonce'] = hex_to_int(s[76:80])
|
|
return h
|
|
|
|
def hash_header(self, header):
|
|
return rev_hex(Hash(self.header_to_string(header).decode('hex')).encode('hex'))
|
|
|
|
def path(self):
|
|
return os.path.join( self.config.path, 'blockchain_headers')
|
|
|
|
def init_headers_file(self):
|
|
filename = self.path()
|
|
if os.path.exists(filename):
|
|
return
|
|
|
|
try:
|
|
import urllib, socket
|
|
socket.setdefaulttimeout(30)
|
|
print_error("downloading ", self.headers_url )
|
|
urllib.urlretrieve(self.headers_url, filename)
|
|
except:
|
|
print_error( "download failed. creating file", filename )
|
|
open(filename,'wb+').close()
|
|
|
|
def save_chunk(self, index, chunk):
|
|
filename = self.path()
|
|
f = open(filename,'rb+')
|
|
f.seek(index*2016*80)
|
|
h = f.write(chunk)
|
|
f.close()
|
|
self.set_local_height()
|
|
|
|
def save_header(self, header):
|
|
data = self.header_to_string(header).decode('hex')
|
|
assert len(data) == 80
|
|
height = header.get('block_height')
|
|
filename = self.path()
|
|
f = open(filename,'rb+')
|
|
f.seek(height*80)
|
|
h = f.write(data)
|
|
f.close()
|
|
self.set_local_height()
|
|
|
|
|
|
def set_local_height(self):
|
|
name = self.path()
|
|
if os.path.exists(name):
|
|
h = os.path.getsize(name)/80 - 1
|
|
if self.local_height != h:
|
|
self.local_height = h
|
|
self.height = self.local_height
|
|
|
|
|
|
def read_header(self, block_height):
|
|
name = self.path()
|
|
if os.path.exists(name):
|
|
f = open(name,'rb')
|
|
f.seek(block_height*80)
|
|
h = f.read(80)
|
|
f.close()
|
|
if len(h) == 80:
|
|
h = self.header_from_string(h)
|
|
return h
|
|
|
|
|
|
def get_target(self, index):
|
|
|
|
max_target = 0x00000000FFFF0000000000000000000000000000000000000000000000000000
|
|
if index == 0: return 0x1d00ffff, max_target
|
|
|
|
first = self.read_header((index-1)*2016)
|
|
last = self.read_header(index*2016-1)
|
|
|
|
nActualTimespan = last.get('timestamp') - first.get('timestamp')
|
|
nTargetTimespan = 14*24*60*60
|
|
nActualTimespan = max(nActualTimespan, nTargetTimespan/4)
|
|
nActualTimespan = min(nActualTimespan, nTargetTimespan*4)
|
|
|
|
bits = last.get('bits')
|
|
# convert to bignum
|
|
MM = 256*256*256
|
|
a = bits%MM
|
|
if a < 0x8000:
|
|
a *= 256
|
|
target = (a) * pow(2, 8 * (bits/MM - 3))
|
|
|
|
# new target
|
|
new_target = min( max_target, (target * nActualTimespan)/nTargetTimespan )
|
|
|
|
# convert it to bits
|
|
c = ("%064X"%new_target)[2:]
|
|
i = 31
|
|
while c[0:2]=="00":
|
|
c = c[2:]
|
|
i -= 1
|
|
|
|
c = eval('0x'+c[0:6])
|
|
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_chunks(self, i, header, height):
|
|
requested_chunks = []
|
|
queue = Queue.Queue()
|
|
min_index = (self.local_height + 1)/2016
|
|
max_index = (height + 1)/2016
|
|
for n in range(min_index, max_index + 1):
|
|
print_error( "requesting chunk", n )
|
|
i.send([ ('blockchain.block.get_chunk',[n])], lambda i,r:queue.put(r))
|
|
requested_chunks.append(n)
|
|
break
|
|
|
|
while requested_chunks:
|
|
try:
|
|
r = queue.get(timeout=1)
|
|
except Queue.Empty:
|
|
continue
|
|
if not r: continue
|
|
|
|
if r.get('error'):
|
|
print_error('Verifier received an error:', r)
|
|
continue
|
|
|
|
# 3. handle response
|
|
params = r['params']
|
|
result = r['result']
|
|
|
|
index = params[0]
|
|
self.verify_chunk(index, result)
|
|
requested_chunks.remove(index)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|