269 lines
8.8 KiB
Python
269 lines
8.8 KiB
Python
#!/usr/bin/env python
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#
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# Electrum - lightweight Bitcoin client
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# Copyright (C) 2012 thomasv@ecdsa.org
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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import threading, time, Queue, os, sys
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from util import user_dir
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from bitcoin import *
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class WalletVerifier(threading.Thread):
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def __init__(self, wallet, config):
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threading.Thread.__init__(self)
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self.daemon = True
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self.config = config
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self.wallet = wallet
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self.interface = self.wallet.interface
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self.interface.register_channel('verifier')
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self.verified_tx = config.get('verified_tx',[])
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self.merkle_roots = config.get('merkle_roots',{}) # hashed by me
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self.targets = config.get('targets',{}) # compute targets
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self.lock = threading.Lock()
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#self.config.set_key('verified_tx', [], True)
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#for i in range(70): self.get_target(i)
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#sys.exit()
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def run(self):
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requested_merkle = []
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requested_chunks = []
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while True:
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# request missing chunks
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max_index = self.wallet.blocks/2016
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if not requested_chunks:
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for i in range(0, max_index + 1):
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# test if we can read the first header of the chunk
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if self.read_header(i*2016): continue
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print "requesting chunk", i
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self.interface.send([ ('blockchain.block.get_chunk',[i])], 'verifier')
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requested_chunks.append(i)
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break
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# todo: request missing blocks too
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# request missing tx merkle
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txlist = self.wallet.get_tx_hashes()
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for tx in txlist:
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if tx not in self.verified_tx:
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if tx not in requested_merkle:
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requested_merkle.append(tx)
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self.request_merkle(tx)
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break
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try:
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r = self.interface.get_response('verifier',timeout=1)
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except Queue.Empty:
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time.sleep(1)
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continue
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# 3. handle response
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method = r['method']
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params = r['params']
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result = r['result']
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if method == 'blockchain.transaction.get_merkle':
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tx_hash = params[0]
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self.verify_merkle(tx_hash, result)
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requested_merkle.remove(tx_hash)
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elif method == 'blockchain.block.get_chunk':
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index = params[0]
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self.verify_chunk(index, result)
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requested_chunks.remove(index)
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elif method == 'blockchain.block.get_header':
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self.verify_header(result)
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def request_merkle(self, tx_hash):
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self.interface.send([ ('blockchain.transaction.get_merkle',[tx_hash]) ], 'verifier')
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def verify_merkle(self, tx_hash, result):
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tx_height = result.get('block_height')
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self.merkle_roots[tx_hash] = self.hash_merkle_root(result['merkle'], tx_hash)
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header = self.read_header(tx_height)
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if header:
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assert header.get('merkle_root') == self.merkle_roots[tx_hash]
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self.verified_tx.append(tx_hash)
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print "verified", tx_hash
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self.config.set_key('verified_tx', self.verified_tx, True)
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def verify_chunk(self, index, hexdata):
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data = hexdata.decode('hex')
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height = index*2016
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numblocks = len(data)/80
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print "validate_chunk", index, numblocks
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if index == 0:
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previous_hash = ("0"*64)
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else:
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prev_header = self.read_header(index*2016-1)
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if prev_header is None: raise
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previous_hash = self.hash_header(prev_header)
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bits, target = self.get_target(index)
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for i in range(numblocks):
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height = index*2016 + i
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raw_header = data[i*80:(i+1)*80]
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header = self.header_from_string(raw_header)
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_hash = self.hash_header(header)
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assert previous_hash == header.get('prev_block_hash')
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assert bits == header.get('bits')
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assert eval('0x'+_hash) < target
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previous_header = header
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previous_hash = _hash
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self.save_chunk(index, data)
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def validate_header(self, header):
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""" if there is a previous or a next block in the list, check the hash"""
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height = header.get('block_height')
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with self.lock:
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self.headers[height] = header # detect conflicts
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prev_header = next_header = None
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if height-1 in self.headers:
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prev_header = self.headers[height-1]
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if height+1 in self.headers:
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next_header = self.headers[height+1]
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if prev_header:
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prev_hash = self.hash_header(prev_header)
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assert prev_hash == header.get('prev_block_hash')
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self.save_header(header)
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if next_header:
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_hash = self.hash_header(header)
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assert _hash == next_header.get('prev_block_hash')
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def header_to_string(self, res):
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s = int_to_hex(res.get('version'),4) \
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+ rev_hex(res.get('prev_block_hash')) \
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+ rev_hex(res.get('merkle_root')) \
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+ int_to_hex(int(res.get('timestamp')),4) \
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+ int_to_hex(int(res.get('bits')),4) \
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+ int_to_hex(int(res.get('nonce')),4)
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return s
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def header_from_string(self, s):
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hex_to_int = lambda s: eval('0x' + s[::-1].encode('hex'))
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h = {}
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h['version'] = hex_to_int(s[0:4])
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h['prev_block_hash'] = hash_encode(s[4:36])
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h['merkle_root'] = hash_encode(s[36:68])
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h['timestamp'] = hex_to_int(s[68:72])
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h['bits'] = hex_to_int(s[72:76])
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h['nonce'] = hex_to_int(s[76:80])
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return h
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def hash_header(self, header):
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return rev_hex(Hash(self.header_to_string(header).decode('hex')).encode('hex'))
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def hash_merkle_root(self, merkle_s, target_hash):
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h = hash_decode(target_hash)
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for item in merkle_s:
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is_left = item[0] == 'L'
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h = Hash( h + hash_decode(item[1:]) ) if is_left else Hash( hash_decode(item[1:]) + h )
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return hash_encode(h)
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def path(self):
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wdir = user_dir()
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if not os.path.exists( wdir ):
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wdir = os.path.dirname(self.config.path)
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return os.path.join( wdir, 'blockchain_headers')
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def save_chunk(self, index, chunk):
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filename = self.path()
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if os.path.exists(filename):
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f = open(filename,'rw+')
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else:
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print "creating file", filename
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f = open(filename,'w+')
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f.seek(index*2016*80)
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h = f.write(chunk)
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f.close()
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def read_header(self, block_height):
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name = self.path()
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if os.path.exists(name):
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f = open(name,'rb')
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f.seek(block_height*80)
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h = f.read(80)
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f.close()
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if len(h) == 80:
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h = self.header_from_string(h)
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return h
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def get_target(self, index):
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max_target = 0x00000000FFFF0000000000000000000000000000000000000000000000000000
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if index == 0: return 0x1d00ffff, max_target
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first = self.read_header((index-1)*2016)
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last = self.read_header(index*2016-1)
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nActualTimespan = last.get('timestamp') - first.get('timestamp')
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nTargetTimespan = 14*24*60*60
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nActualTimespan = max(nActualTimespan, nTargetTimespan/4)
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nActualTimespan = min(nActualTimespan, nTargetTimespan*4)
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bits = last.get('bits')
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# convert to bignum
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MM = 256*256*256
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a = bits%MM
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if a < 0x8000:
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a *= 256
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target = (a) * pow(2, 8 * (bits/MM - 3))
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# new target
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new_target = min( max_target, (target * nActualTimespan)/nTargetTimespan )
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# convert it to bits
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c = ("%064X"%new_target)[2:]
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i = 31
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while c[0:2]=="00":
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c = c[2:]
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i -= 1
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c = eval('0x'+c[0:6])
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if c > 0x800000:
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c /= 256
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i += 1
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new_bits = c + MM * i
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# print "%3d"%index, "%8x"%bits, "%64X"%new_target, hex(c)[2:].upper(), hex(new_bits)
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return new_bits, new_target
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