p2pool.py

   1 from __future__ import division
   2
   3 import bitcoin_p2p
   4 import conv
   5
   6 chain_id_type = bitcoin_p2p.ComposedType([
   7     ('last_p2pool_block_hash', bitcoin_p2p.HashType()),
   8     ('bits', bitcoin_p2p.StructType('<I')),
   9 ])
  10
  11 coinbase_type = bitcoin_p2p.ComposedType([
  12     ('identifier', bitcoin_p2p.StructType('<Q')),
  13     ('last_p2pool_block_hash', bitcoin_p2p.HashType()),
  14     ('previous_p2pool_share_hash', bitcoin_p2p.HashType()),
  15     ('subsidy', bitcoin_p2p.StructType('<Q')),
  16     ('last_share_index', bitcoin_p2p.StructType('<I')),
  17     ('nonce', bitcoin_p2p.StructType('<Q')),
  18 ])
  19
  20 merkle_branch = bitcoin_p2p.ListType(bitcoin_p2p.ComposedType([
  21     ('side', bitcoin_p2p.StructType('<B')),
  22     ('hash', bitcoin_p2p.HashType()),
  23 ]))
  24
  25 share1 = bitcoin_p2p.ComposedType([
  26     ('header', bitcoin_p2p.block_header),
  27     ('gentx', bitcoin_p2p.ComposedType([
  28         ('tx', bitcoin_p2p.tx),
  29         ('merkle_branch', merkle_branch),
  30     ])),
  31 ])
  32
  33 def calculate_merkle_branch(txn_list, index):
  34     hash_list = [(bitcoin_p2p.doublesha(bitcoin_p2p.tx.pack(data)), i == index, []) for i, data in enumerate(txn_list)]
  35
  36     while len(hash_list) > 1:
  37         hash_list = [
  38             (
  39                 bitcoin_p2p.doublesha(bitcoin_p2p.merkle_record.pack(dict(left=left, right=right))),
  40                 left_f or right_f,
  41                 (left_l if left_f else right_l) + [dict(side=1, hash=right) if left_f else dict(side=0, hash=left)],
  42             )
  43             for (left, left_f, left_l), (right, right_f, right_l) in
  44                 zip(hash_list[::2], hash_list[1::2] + [hash_list[::2][-1]])
  45         ]
  46
  47     assert check_merkle_branch(txn_list[index], hash_list[0][2]) == hash_list[0][0]
  48
  49     return hash_list[0][2]
  50
  51 def check_merkle_branch(txn, branch):
  52     hash_ = bitcoin_p2p.doublesha(bitcoin_p2p.tx.pack(txn))
  53     for step in branch:
  54         if not step['side']:
  55             hash_ = bitcoin_p2p.doublesha(bitcoin_p2p.merkle_record.pack(dict(left=step['hash'], right=hash_)))
  56         else:
  57             hash_ = bitcoin_p2p.doublesha(bitcoin_p2p.merkle_record.pack(dict(left=hash_, right=step['hash'])))
  58     return hash_
  59
  60 def txns_to_gentx(txns):
  61     return dict(
  62         tx=txns[0],
  63         merkle_branch=calculate_merkle_branch(txns, 0),
  64     )
  65
  66 class Share(object):
  67     def __init__(self, header, txns=None, gentx=None):
  68         self.header = header
  69         self.hash = bitcoin_p2p.block_hash(header)
  70
  71         self.txns = txns
  72         if txns is None:
  73             if gentx is not None:
  74                 self.gentx = gentx
  75                 if check_merkle_branch(gentx['tx'], gentx['merkle_branch']) != header['merkle_root']:
  76                     #print '%x' % check_merkle_branch(gentx['tx'], gentx['merkle_branch'])
  77                     #print '%x' % header['merkle_root']
  78                     raise ValueError("gentx doesn't match header")
  79             else:
  80                 raise ValueError('need either txns or gentx')
  81         else:
  82             self.gentx = txns_to_gentx(txns)
  83             if gentx is not None:
  84                 if gentx != self.gentx:
  85                     raise ValueError('invalid gentx')
  86
  87         self.coinbase = coinbase_type.unpack(self.gentx['tx']['tx_ins'][0]['script'], ignore_extra=True)
  88         self.previous_share_hash = self.coinbase['previous_p2pool_share_hash'] if self.coinbase['previous_p2pool_share_hash'] != 2**256 - 1 else None
  89         self.chain_id_data = chain_id_type.pack(dict(last_p2pool_block_hash=self.coinbase['last_p2pool_block_hash'], bits=self.header['bits']))
  90
  91     def as_block(self):
  92         if self.txns is None:
  93             raise ValueError('share does not contain all txns')
  94         return dict(header=self.header, txns=self.txns)
  95
  96     def as_share1(self):
  97         return dict(header=self.header, gentx=self.gentx)
  98
  99     def check(self, chain, height, previous_share2, net):
 100         if self.chain_id_data != chain.chain_id_data:
 101             raise ValueError('wrong chain')
 102         if self.hash > net.TARGET_MULTIPLIER*conv.bits_to_target(self.header['bits']):
 103             raise ValueError('not enough work!')
 104
 105         t = self.gentx['tx']
 106         t2, shares = generate_transaction(
 107             last_p2pool_block_hash=chain.last_p2pool_block_hash,
 108             previous_share2=previous_share2,
 109             add_script=t['tx_outs'][self.coinbase['last_share_index']]['script'],
 110             subsidy=self.coinbase['subsidy'],
 111             nonce=self.coinbase['nonce'],
 112             net=net,
 113         )
 114         if t2 != t:
 115             raise ValueError('invalid generate txn')
 116
 117         return Share2(self, shares, height)
 118
 119 class Share2(object):
 120     '''Share with associated data'''
 121
 122     def __init__(self, share, shares, height):
 123         self.share = share
 124         self.shares = map(intern, shares)
 125         self.height = height
 126         self.shared = False
 127
 128     def flag_shared(self):
 129         self.shared = True
 130
 131 def generate_transaction(last_p2pool_block_hash, previous_share2, add_script, subsidy, nonce, net):
 132     shares = (previous_share2.shares if previous_share2 is not None else [net.SCRIPT]*net.SPREAD)[1:-1] + [add_script, add_script]
 133
 134     dest_weights = {}
 135     for script in shares:
 136         dest_weights[script] = dest_weights.get(script, 0) + 1
 137     total_weight = sum(dest_weights.itervalues())
 138
 139     amounts = dict((script, subsidy*weight*63//(64*total_weight)) for (script, weight) in dest_weights.iteritems())
 140     amounts[net.SCRIPT] = amounts.get(net.SCRIPT, 0) + subsidy//64 # prevent fake previous p2pool blocks
 141     amounts[net.SCRIPT] = amounts.get(net.SCRIPT, 0) + subsidy - sum(amounts.itervalues()) # collect any extra
 142
 143     dests = sorted(amounts.iterkeys())
 144
 145     return dict(
 146         version=1,
 147         tx_ins=[dict(
 148             previous_output=dict(index=4294967295, hash=0),
 149             sequence=4294967295,
 150             script=coinbase_type.pack(dict(
 151                 identifier=net.IDENTIFIER,
 152                 last_p2pool_block_hash=last_p2pool_block_hash,
 153                 previous_p2pool_share_hash=previous_share2.share.hash if previous_share2 is not None else 2**256 - 1,
 154                 subsidy=subsidy,
 155                 last_share_index=dests.index(add_script),
 156                 nonce=nonce,
 157             )),
 158         )],
 159         tx_outs=[dict(value=amounts[script], script=script) for script in dests if amounts[script]],
 160         lock_time=0,
 161     ), shares
 162
 163
 164 # TARGET_MULTIPLIER needs to be less than the current difficulty to prevent miner clients from missing shares
 165
 166 class Testnet(object):
 167     TARGET_MULTIPLIER = 30
 168     SPREAD = 30
 169     ROOT_BLOCK = 0x3575d1e7b40fe37ad12d41169a1012d26df5f3c35486e2abfbe9d2c
 170     SCRIPT = '410489175c7658845fd7c33d61029ebf4042e8386443ff6e6628fdb5ac938c31072dc61cee691ae1e8355c3a87cb4813cc9bf036fdb09078d35eacf9e9ab52374ebeac'.decode('hex')
 171     IDENTIFIER = 0x808330dc87e313b7
 172
 173 class Main(object):
 174     TARGET_MULTIPLIER = SPREAD = 600
 175     ROOT_BLOCK = 0xf78e83f63fd0f4e0f584d3bc2c7010f679834cd8886d61876d
 176     SCRIPT = '410441ccbae5ca6ecfaa014028b0c49df2cd5588cb6058ac260d650bc13c9ec466f95c7a6d80a3ea7f7b8e2e87e49b96081e9b20415b06433d7a5b6a156b58690d96ac'.decode('hex')
 177     IDENTIFIER = 0x49ddc0b4938708ad