p2pool/data.py

   1 from __future__ import division
   2
   3 import itertools
   4 import random
   5 import time
   6
   7 from twisted.python import log
   8
   9 from p2pool.bitcoin import data as bitcoin_data
  10 from p2pool.bitcoin import script
  11 from p2pool.util import memoize, expiring_dict, math, skiplist
  12
  13
  14 merkle_branch_type = bitcoin_data.ListType(bitcoin_data.ComposedType([
  15     ('side', bitcoin_data.StructType('<B')), # enum?
  16     ('hash', bitcoin_data.HashType()),
  17 ]))
  18
  19
  20 share_data_type = bitcoin_data.ComposedType([
  21     ('previous_share_hash', bitcoin_data.PossiblyNone(0, bitcoin_data.HashType())),
  22     ('target', bitcoin_data.FloatingIntegerType()),
  23     ('nonce', bitcoin_data.VarStrType()),
  24 ])
  25
  26
  27 coinbase_type = bitcoin_data.ComposedType([
  28     ('identifier', bitcoin_data.FixedStrType(8)),
  29     ('share_data', share_data_type),
  30 ])
  31
  32 share_info_type = bitcoin_data.ComposedType([
  33     ('share_data', share_data_type),
  34     ('new_script', bitcoin_data.VarStrType()),
  35     ('subsidy', bitcoin_data.StructType('<Q')),
  36 ])
  37
  38
  39 share1a_type = bitcoin_data.ComposedType([
  40     ('header', bitcoin_data.block_header_type),
  41     ('share_info', share_info_type),
  42     ('merkle_branch', merkle_branch_type),
  43 ])
  44
  45 share1b_type = bitcoin_data.ComposedType([
  46     ('header', bitcoin_data.block_header_type),
  47     ('share_info', share_info_type),
  48     ('other_txs', bitcoin_data.ListType(bitcoin_data.tx_type)),
  49 ])
  50
  51 def calculate_merkle_branch(txs, index):
  52     hash_list = [(bitcoin_data.tx_type.hash256(tx), i == index, []) for i, tx in enumerate(txs)]
  53
  54     while len(hash_list) > 1:
  55         hash_list = [
  56             (
  57                 bitcoin_data.merkle_record_type.hash256(dict(left=left, right=right)),
  58                 left_f or right_f,
  59                 (left_l if left_f else right_l) + [dict(side=1, hash=right) if left_f else dict(side=0, hash=left)],
  60             )
  61             for (left, left_f, left_l), (right, right_f, right_l) in
  62                 zip(hash_list[::2], hash_list[1::2] + [hash_list[::2][-1]])
  63         ]
  64
  65     assert hash_list[0][1]
  66     assert check_merkle_branch(txs[index], hash_list[0][2]) == hash_list[0][0]
  67
  68     return hash_list[0][2]
  69
  70 def check_merkle_branch(tx, branch):
  71     hash_ = bitcoin_data.tx_type.hash256(tx)
  72     for step in branch:
  73         if not step['side']:
  74             hash_ = bitcoin_data.merkle_record_type.hash256(dict(left=step['hash'], right=hash_))
  75         else:
  76             hash_ = bitcoin_data.merkle_record_type.hash256(dict(left=hash_, right=step['hash']))
  77     return hash_
  78
  79 def gentx_to_share_info(gentx):
  80     return dict(
  81         share_data=coinbase_type.unpack(gentx['tx_ins'][0]['script'])['share_data'],
  82         subsidy=sum(tx_out['value'] for tx_out in gentx['tx_outs']),
  83         new_script=gentx['tx_outs'][-1]['script'],
  84     )
  85
  86 def share_info_to_gentx(share_info, block_target, tracker, net):
  87     return generate_transaction(
  88         tracker=tracker,
  89         previous_share_hash=share_info['share_data']['previous_share_hash'],
  90         new_script=share_info['new_script'],
  91         subsidy=share_info['subsidy'],
  92         nonce=share_info['share_data']['nonce'],
  93         block_target=block_target,
  94         net=net,
  95     )
  96
  97 class Share(object):
  98     peer = None
  99     highest_block_on_arrival = None
 100
 101     @classmethod
 102     def from_block(cls, block):
 103         return cls(block['header'], gentx_to_share_info(block['txs'][0]), other_txs=block['txs'][1:])
 104
 105     @classmethod
 106     def from_share1a(cls, share1a):
 107         return cls(**share1a)
 108
 109     @classmethod
 110     def from_share1b(cls, share1b):
 111         return cls(**share1b)
 112
 113     def __init__(self, header, share_info, merkle_branch=None, other_txs=None):
 114         if merkle_branch is None and other_txs is None:
 115             raise ValueError('need either merkle_branch or other_txs')
 116         if other_txs is not None:
 117             new_merkle_branch = calculate_merkle_branch([dict(version=0, tx_ins=[], tx_outs=[], lock_time=0)] + other_txs, 0)
 118             if merkle_branch is not None:
 119                 if merke_branch != new_merkle_branch:
 120                     raise ValueError('invalid merkle_branch and other_txs')
 121             merkle_branch = new_merkle_branch
 122
 123         if len(merkle_branch) > 16:
 124             raise ValueError('merkle_branch too long!')
 125
 126         self.header = header
 127         self.previous_block = header['previous_block']
 128         self.share_info = share_info
 129         self.merkle_branch = merkle_branch
 130         self.other_txs = other_txs
 131
 132         self.timestamp = self.header['timestamp']
 133
 134         self.share_data = self.share_info['share_data']
 135         self.new_script = self.share_info['new_script']
 136         self.subsidy = self.share_info['subsidy']
 137
 138         if len(self.new_script) > 100:
 139             raise ValueError('new_script too long!')
 140
 141         self.previous_hash = self.previous_share_hash = self.share_data['previous_share_hash']
 142         self.target = self.share_data['target']
 143         self.nonce = self.share_data['nonce']
 144
 145         if len(self.nonce) > 20:
 146             raise ValueError('nonce too long!')
 147
 148         self.bitcoin_hash = bitcoin_data.block_header_type.hash256(header)
 149         self.hash = share1a_type.hash256(self.as_share1a())
 150
 151         if self.bitcoin_hash > self.target:
 152             print 'hash', hex(self.bitcoin_hash)
 153             print 'targ', hex(self.target)
 154             raise ValueError('not enough work!')
 155
 156         if script.get_sigop_count(self.new_script) > 1:
 157             raise ValueError('too many sigops!')
 158
 159         self.time_seen = time.time()
 160         self.shared = False
 161
 162     def as_block(self, tracker, net):
 163         if self.other_txs is None:
 164             raise ValueError('share does not contain all txs')
 165
 166         gentx = share_info_to_gentx(self.share_info, self.header['target'], tracker, net)
 167
 168         return dict(header=self.header, txs=[gentx] + self.other_txs)
 169
 170     def as_share1a(self):
 171         return dict(header=self.header, share_info=self.share_info, merkle_branch=self.merkle_branch)
 172
 173     def as_share1b(self):
 174         return dict(header=self.header, share_info=self.share_info, other_txs=self.other_txs)
 175
 176     def check(self, tracker, now, net):
 177         import time
 178         if self.previous_share_hash is not None:
 179             if self.header['timestamp'] <= math.median((s.timestamp for s in itertools.islice(tracker.get_chain_to_root(self.previous_share_hash), 11)), use_float=False):
 180                 raise ValueError('share from too far in the past!')
 181
 182         if self.header['timestamp'] > now + 2*60*60:
 183             raise ValueError('share from too far in the future!')
 184
 185         gentx = share_info_to_gentx(self.share_info, self.header['target'], tracker, net)
 186
 187         if check_merkle_branch(gentx, self.merkle_branch) != self.header['merkle_root']:
 188             raise ValueError('''gentx doesn't match header via merkle_branch''')
 189
 190         if self.other_txs is not None:
 191             if bitcoin_data.merkle_hash([gentx] + self.other_txs) != self.header['merkle_root']:
 192                 raise ValueError('''gentx doesn't match header via other_txs''')
 193
 194             if len(bitcoin_data.block_type.pack(dict(header=self.header, txs=[gentx] + self.other_txs))) > 1000000 - 1000:
 195                 raise ValueError('''block size too large''')
 196
 197         self.gentx = gentx
 198
 199     def flag_shared(self):
 200         self.shared = True
 201
 202     def __repr__(self):
 203         return '<Share %s>' % (' '.join('%s=%r' % (k, v) for k, v in self.__dict__.iteritems()),)
 204
 205 def get_pool_attempts_per_second(tracker, previous_share_hash, net):
 206     # XXX could be optimized to use nth_parent and cumulative_weights
 207     chain = list(itertools.islice(tracker.get_chain_to_root(previous_share_hash), net.TARGET_LOOKBEHIND))
 208     attempts = sum(bitcoin_data.target_to_average_attempts(share.target) for share in chain[:-1])
 209     time = chain[0].timestamp - chain[-1].timestamp
 210     if time == 0:
 211         time = 1
 212     return attempts//time
 213
 214 def generate_transaction(tracker, previous_share_hash, new_script, subsidy, nonce, block_target, net):
 215     if __debug__:
 216         print "start generate_transaction"
 217     height, last = tracker.get_height_and_last(previous_share_hash)
 218     if height < net.TARGET_LOOKBEHIND:
 219         target = bitcoin_data.FloatingIntegerType().truncate_to(2**256//2**20 - 1)
 220     else:
 221         attempts_per_second = get_pool_attempts_per_second(tracker, previous_share_hash, net)
 222         pre_target = 2**256//(net.SHARE_PERIOD*attempts_per_second) - 1
 223         previous_share = tracker.shares[previous_share_hash] if previous_share_hash is not None else None
 224         pre_target2 = math.clip(pre_target, (previous_share.target*9//10, previous_share.target*11//10))
 225         pre_target3 = math.clip(pre_target2, (0, net.MAX_TARGET))
 226         target = bitcoin_data.FloatingIntegerType().truncate_to(pre_target3)
 227
 228     attempts_to_block = bitcoin_data.target_to_average_attempts(block_target)
 229     max_weight = net.SPREAD * attempts_to_block
 230
 231     '''
 232     class fake_share(object):
 233         pass
 234     fake_share.new_script = new_script
 235     fake_share.target = target
 236
 237     dest_weights = {}
 238     total_weight = 0
 239     for share in itertools.chain([fake_share], itertools.islice(tracker.get_chain_to_root(previous_share_hash), net.CHAIN_LENGTH)):
 240         weight = bitcoin_data.target_to_average_attempts(share.target)
 241         if weight > max_weight - total_weight:
 242             weight = max_weight - total_weight
 243
 244         dest_weights[share.new_script] = dest_weights.get(share.new_script, 0) + weight
 245         total_weight += weight
 246
 247         if total_weight == max_weight:
 248             break
 249     '''
 250
 251     this_weight = min(bitcoin_data.target_to_average_attempts(target), max_weight)
 252     other_weights, other_weights_total = tracker.get_cumulative_weights(previous_share_hash, min(height, net.CHAIN_LENGTH), max(0, max_weight - this_weight))
 253     dest_weights, total_weight = math.add_dicts([{new_script: this_weight}, other_weights]), this_weight + other_weights_total
 254     total_weight = sum(dest_weights.itervalues())
 255
 256     amounts = dict((script, subsidy*(396*weight)//(400*total_weight)) for (script, weight) in dest_weights.iteritems())
 257     amounts[new_script] = amounts.get(new_script, 0) + subsidy*2//400
 258     amounts[net.SCRIPT] = amounts.get(net.SCRIPT, 0) + subsidy*2//400
 259     amounts[net.SCRIPT] = amounts.get(net.SCRIPT, 0) + subsidy - sum(amounts.itervalues()) # collect any extra
 260     if sum(amounts.itervalues()) != subsidy:
 261         raise ValueError()
 262     if any(x < 0 for x in amounts.itervalues()):
 263         raise ValueError()
 264
 265     pre_dests = sorted(amounts.iterkeys(), key=lambda script: (amounts[script], script))
 266     pre_dests = pre_dests[-4000:] # block length limit, unlikely to ever be hit
 267
 268     dests = sorted(pre_dests, key=lambda script: (script == new_script, script))
 269     assert dests[-1] == new_script
 270
 271     if __debug__:
 272         print "end generate_transaction"
 273
 274     return dict(
 275         version=1,
 276         tx_ins=[dict(
 277             previous_output=None,
 278             sequence=None,
 279             script=coinbase_type.pack(dict(
 280                 identifier=net.IDENTIFIER,
 281                 share_data=dict(
 282                     previous_share_hash=previous_share_hash,
 283                     nonce=nonce,
 284                     target=target,
 285                 ),
 286             )),
 287         )],
 288         tx_outs=[dict(value=amounts[script], script=script) for script in dests if amounts[script]],
 289         lock_time=0,
 290     )
 291
 292
 293
 294 class OkayTracker(bitcoin_data.Tracker):
 295     def __init__(self, net):
 296         bitcoin_data.Tracker.__init__(self)
 297         self.net = net
 298         self.verified = bitcoin_data.Tracker()
 299
 300         self.get_cumulative_weights = skiplist.WeightsSkipList(self)
 301
 302     def attempt_verify(self, share, now):
 303         if share.hash in self.verified.shares:
 304             return True
 305         height, last = self.get_height_and_last(share.hash)
 306         if height < self.net.CHAIN_LENGTH and last is not None:
 307             raise AssertionError()
 308         try:
 309             share.check(self, now, self.net)
 310         except:
 311             print
 312             print 'Share check failed:'
 313             log.err()
 314             print
 315             return False
 316         else:
 317             self.verified.add(share)
 318             return True
 319
 320     def think(self, ht, previous_block, now):
 321         if __debug__:
 322             print "start think"
 323
 324         desired = set()
 325
 326         # O(len(self.heads))
 327         #   make 'unverified heads' set?
 328         # for each overall head, attempt verification
 329         # if it fails, attempt on parent, and repeat
 330         # if no successful verification because of lack of parents, request parent
 331         bads = set()
 332         for head in set(self.heads) - set(self.verified.heads):
 333             head_height, last = self.get_height_and_last(head)
 334
 335             for share in itertools.islice(self.get_chain_known(head), None if last is None else min(5, max(0, head_height - self.net.CHAIN_LENGTH))):
 336                 if self.attempt_verify(share, now):
 337                     break
 338                 if share.hash in self.heads:
 339                     bads.add(share.hash)
 340             else:
 341                 if last is not None:
 342                     desired.add((self.shares[random.choice(list(self.reverse_shares[last]))].peer, last))
 343         for bad in bads:
 344             assert bad not in self.verified.shares
 345             assert bad in self.heads
 346             self.remove(bad)
 347
 348         # try to get at least CHAIN_LENGTH height for each verified head, requesting parents if needed
 349         for head in list(self.verified.heads):
 350             head_height, last_hash = self.verified.get_height_and_last(head)
 351             last_height, last_last_hash = self.get_height_and_last(last_hash)
 352             # XXX review boundary conditions
 353             want = max(self.net.CHAIN_LENGTH - head_height, 0)
 354             can = max(last_height - 1 - self.net.CHAIN_LENGTH, 0) if last_last_hash is not None else last_height
 355             get = min(want, can)
 356             #print 'Z', head_height, last_hash is None, last_height, last_last_hash is None, want, can, get
 357             for share in itertools.islice(self.get_chain_known(last_hash), get):
 358                 if not self.attempt_verify(share, now):
 359                     break
 360             if head_height < self.net.CHAIN_LENGTH and last_last_hash is not None:
 361                 desired.add((self.verified.shares[random.choice(list(self.verified.reverse_shares[last_hash]))].peer, last_last_hash))
 362
 363         # decide best tree
 364         best_tail = max(self.verified.tails, key=lambda h: self.score(max(self.verified.tails[h], key=self.verified.get_height), ht)) if self.verified.tails else None
 365         # decide best verified head
 366         scores = sorted(self.verified.tails.get(best_tail, []), key=lambda h: (self.verified.get_work(h), ht.get_min_height(self.verified.shares[h].previous_block), -self.verified.shares[h].time_seen))
 367
 368
 369         #if __debug__:
 370             #print len(self.verified.tails.get(best_tail, []))
 371             #for a in scores:
 372             #    print '   ', '%x'%a, self.score(a, ht)
 373
 374         for share_hash in scores[:-5]:
 375             if self.shares[share_hash].time_seen > time.time() - 30:
 376                 continue
 377             self.remove(share_hash)
 378             self.verified.remove(share_hash)
 379
 380         #for tail, heads in list(self.tails.iteritems()):
 381         #    if min(self.get_height(head) for head in heads) > 2*net.CHAIN_LENGTH + 10:
 382         #        self.remove(tail)
 383         #        self.verified.remove(tail)
 384
 385         best = scores[-1] if scores else None
 386
 387         if best is not None:
 388             best_share = self.verified.shares[best]
 389             if ht.get_min_height(best_share.header['previous_block']) < ht.get_min_height(previous_block) and best_share.bitcoin_hash != previous_block and best_share.peer is not None:
 390                 if __debug__:
 391                     print "stale detected!"
 392                 best = best_share.previous_hash
 393
 394         if __debug__:
 395             print "end think"
 396
 397         return best, desired
 398
 399     @memoize.memoize_with_backing(expiring_dict.ExpiringDict(5, get_touches=False))
 400     def score(self, share_hash, ht):
 401         head_height, last = self.verified.get_height_and_last(share_hash)
 402         score2 = 0
 403         attempts = 0
 404         max_height = 0
 405         # XXX should only look past a certain share, not at recent ones
 406         share2_hash = self.verified.get_nth_parent_hash(share_hash, min(self.net.CHAIN_LENGTH//2, head_height//2)) if last is not None else share_hash
 407         # XXX this must go in the opposite direction for max_height to make sense
 408         for share in reversed(list(itertools.islice(self.verified.get_chain_known(share2_hash), self.net.CHAIN_LENGTH))):
 409             max_height = max(max_height, ht.get_min_height(share.header['previous_block']))
 410             attempts += bitcoin_data.target_to_average_attempts(share.target)
 411             this_score = attempts//(ht.get_highest_height() - max_height + 1)
 412             if this_score > score2:
 413                 score2 = this_score
 414         return min(head_height, self.net.CHAIN_LENGTH), score2
 415
 416
 417 class Mainnet(bitcoin_data.Mainnet):
 418     SHARE_PERIOD = 5 # seconds
 419     CHAIN_LENGTH = 24*60*60//5 # shares
 420     TARGET_LOOKBEHIND = 200 # shares
 421     SPREAD = 3 # blocks
 422     SCRIPT = '4104ffd03de44a6e11b9917f3a29f9443283d9871c9d743ef30d5eddcd37094b64d1b3d8090496b53256786bf5c82932ec23c3b74d9f05a6f95a8b5529352656664bac'.decode('hex')
 423     IDENTIFIER = 'fc70035c7a81bc6f'.decode('hex')
 424     PREFIX = '2472ef181efcd37b'.decode('hex')
 425     ADDRS_TABLE = 'addrs'
 426     P2P_PORT = 9333
 427     MAX_TARGET = 2**256//2**32 - 1
 428
 429 class Testnet(bitcoin_data.Testnet):
 430     SHARE_PERIOD = 1 # seconds
 431     CHAIN_LENGTH = 24*60*60//5 # shares
 432     TARGET_LOOKBEHIND = 200 # shares
 433     SPREAD = 3 # blocks
 434     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
 435     IDENTIFIER = '5fc2be2d4f0d6bfb'.decode('hex')
 436     PREFIX = '3f6057a15036f441'.decode('hex')
 437     ADDRS_TABLE = 'addrs_testnet'
 438     P2P_PORT = 19333
 439     MAX_TARGET = 2**256//2**20 - 1