updated transition time (and fixed an accidental change)
[p2pool.git] / p2pool / data.py
1 from __future__ import division
2
3 TRANSITION_TIME = 1322561023
4
5 import itertools
6 import random
7 import time
8 import os
9
10 from twisted.python import log
11
12 import p2pool
13 from p2pool import skiplists
14 from p2pool.bitcoin import data as bitcoin_data, script, networks
15 from p2pool.util import memoize, expiring_dict, math
16
17
18 merkle_branch_type = bitcoin_data.ListType(bitcoin_data.ComposedType([
19     ('side', bitcoin_data.StructType('<B')), # enum?
20     ('hash', bitcoin_data.HashType()),
21 ]))
22
23
24 share_data_type = bitcoin_data.ComposedType([
25     ('previous_share_hash', bitcoin_data.PossiblyNoneType(0, bitcoin_data.HashType())),
26     ('target', bitcoin_data.FloatingIntegerType()),
27     ('nonce', bitcoin_data.VarStrType()),
28 ])
29
30
31 coinbase_type = bitcoin_data.ComposedType([
32     ('identifier', bitcoin_data.FixedStrType(8)),
33     ('share_data', share_data_type),
34 ])
35
36 share_info_type = bitcoin_data.ComposedType([
37     ('share_data', share_data_type),
38     ('new_script', bitcoin_data.VarStrType()),
39     ('subsidy', bitcoin_data.StructType('<Q')),
40 ])
41
42
43 share1a_type = bitcoin_data.ComposedType([
44     ('header', bitcoin_data.block_header_type),
45     ('share_info', share_info_type),
46     ('merkle_branch', merkle_branch_type),
47 ])
48
49 share1b_type = bitcoin_data.ComposedType([
50     ('header', bitcoin_data.block_header_type),
51     ('share_info', share_info_type),
52     ('other_txs', bitcoin_data.ListType(bitcoin_data.tx_type)),
53 ])
54
55 new_share_data_type = bitcoin_data.ComposedType([
56     ('previous_share_hash', bitcoin_data.PossiblyNoneType(0, bitcoin_data.HashType())),
57     ('coinbase', bitcoin_data.VarStrType()),
58     ('nonce', bitcoin_data.VarStrType()),
59     ('new_script', bitcoin_data.VarStrType()),
60     ('subsidy', bitcoin_data.StructType('<Q')),
61     ('donation', bitcoin_data.StructType('<H')),
62     ('timestamp', bitcoin_data.StructType('<I')),
63     ('stale_frac', bitcoin_data.StructType('<B')),
64 ])
65
66 new_share_info_type = bitcoin_data.ComposedType([
67     ('new_share_data', new_share_data_type),
68     ('target', bitcoin_data.FloatingIntegerType()),
69 ])
70
71 new_share1a_type = bitcoin_data.ComposedType([
72     ('header', bitcoin_data.block_header_type),
73     ('share_info', new_share_info_type),
74     ('merkle_branch', bitcoin_data.merkle_branch_type),
75 ])
76
77 new_share1b_type = bitcoin_data.ComposedType([
78     ('header', bitcoin_data.block_header_type),
79     ('share_info', new_share_info_type),
80     ('other_txs', bitcoin_data.ListType(bitcoin_data.tx_type)),
81 ])
82
83 # type:
84 # 0: new_share1a
85 # 1: new_share1b
86
87 new_share_type = bitcoin_data.ComposedType([
88     ('type', bitcoin_data.VarIntType()),
89     ('contents', bitcoin_data.VarStrType()),
90 ])
91
92 def calculate_merkle_branch(txs, index):
93     hash_list = [(bitcoin_data.tx_type.hash256(tx), i == index, []) for i, tx in enumerate(txs)]
94     
95     while len(hash_list) > 1:
96         hash_list = [
97             (
98                 bitcoin_data.merkle_record_type.hash256(dict(left=left, right=right)),
99                 left_f or right_f,
100                 (left_l if left_f else right_l) + [dict(side=1, hash=right) if left_f else dict(side=0, hash=left)],
101             )
102             for (left, left_f, left_l), (right, right_f, right_l) in
103                 zip(hash_list[::2], hash_list[1::2] + [hash_list[::2][-1]])
104         ]
105     
106     assert hash_list[0][1]
107     assert check_merkle_branch(txs[index], hash_list[0][2]) == hash_list[0][0]
108     
109     return hash_list[0][2]
110
111 def check_merkle_branch(tx, branch):
112     hash_ = bitcoin_data.tx_type.hash256(tx)
113     for step in branch:
114         if not step['side']:
115             hash_ = bitcoin_data.merkle_record_type.hash256(dict(left=step['hash'], right=hash_))
116         else:
117             hash_ = bitcoin_data.merkle_record_type.hash256(dict(left=hash_, right=step['hash']))
118     return hash_
119
120 def share_info_to_gentx(share_info, block_target, tracker, net):
121     return generate_transaction(
122         tracker=tracker,
123         previous_share_hash=share_info['share_data']['previous_share_hash'],
124         new_script=share_info['new_script'],
125         subsidy=share_info['subsidy'],
126         nonce=share_info['share_data']['nonce'],
127         block_target=block_target,
128         net=net,
129     )[1]
130
131 class Share(object):
132     donation = int(0.005*65535 + 0.5)
133     
134     @classmethod
135     def from_share1a(cls, share1a, net):
136         return cls(net, **share1a)
137     
138     @classmethod
139     def from_share1b(cls, share1b, net):
140         return cls(net, **share1b)
141     
142     __slots__ = 'header previous_block share_info merkle_branch other_txs timestamp share_data new_script subsidy previous_hash previous_share_hash target nonce pow_hash header_hash hash time_seen peer'.split(' ')
143     
144     def __init__(self, net, header, share_info, merkle_branch=None, other_txs=None):
145         if merkle_branch is None and other_txs is None:
146             raise ValueError('need either merkle_branch or other_txs')
147         if other_txs is not None:
148             new_merkle_branch = calculate_merkle_branch([dict(version=0, tx_ins=[], tx_outs=[], lock_time=0)] + other_txs, 0)
149             if merkle_branch is not None:
150                 if merke_branch != new_merkle_branch:
151                     raise ValueError('invalid merkle_branch and other_txs')
152             merkle_branch = new_merkle_branch
153         
154         if len(merkle_branch) > 16:
155             raise ValueError('merkle_branch too long!')
156         
157         self.header = header
158         self.previous_block = header['previous_block']
159         self.share_info = share_info
160         self.merkle_branch = merkle_branch
161         self.other_txs = other_txs
162         
163         self.timestamp = self.header['timestamp']
164         
165         self.share_data = self.share_info['share_data']
166         self.new_script = self.share_info['new_script']
167         self.subsidy = self.share_info['subsidy']
168         
169         if len(self.new_script) > 100:
170             raise ValueError('new_script too long!')
171         
172         self.previous_hash = self.previous_share_hash = self.share_data['previous_share_hash']
173         self.target = self.share_data['target']
174         self.nonce = self.share_data['nonce']
175         
176         if len(self.nonce) > 100:
177             raise ValueError('nonce too long!')
178         
179         self.pow_hash = net.BITCOIN_POW_FUNC(header)
180         self.header_hash = bitcoin_data.block_header_type.hash256(header)
181         
182         if net.BITCOIN_POW_FUNC == bitcoin_data.block_header_type.scrypt:
183             # compatibility hack
184             self.hash = share1a_type.scrypt(self.as_share1a())
185         else:
186             self.hash = share1a_type.hash256(self.as_share1a())
187         
188         if self.pow_hash > self.target:
189             print 'hash %x' % self.pow_hash
190             print 'targ %x' % self.target
191             raise ValueError('not enough work!')
192         
193         if script.get_sigop_count(self.new_script) > 1:
194             raise ValueError('too many sigops!')
195         
196         # XXX eww
197         self.time_seen = time.time()
198         self.peer = None
199     
200     def as_block(self, tracker, net):
201         if self.other_txs is None:
202             raise ValueError('share does not contain all txs')
203         
204         gentx = share_info_to_gentx(self.share_info, self.header['target'], tracker, net)
205         
206         return dict(header=self.header, txs=[gentx] + self.other_txs)
207     
208     def as_share1a(self):
209         return dict(header=self.header, share_info=self.share_info, merkle_branch=self.merkle_branch)
210     
211     def as_share1b(self):
212         if self.other_txs is None:
213             raise ValueError('share does not contain all txs')
214         
215         return dict(header=self.header, share_info=self.share_info, other_txs=self.other_txs)
216     
217     def check(self, tracker, now, net):
218         if self.header['timestamp'] >= TRANSITION_TIME:
219             raise AssertionError('transitioning...')
220         import time
221         if self.previous_share_hash is not None:
222             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):
223                 raise ValueError('share from too far in the past!')
224         
225         if self.header['timestamp'] > now + 2*60*60:
226             raise ValueError('share from too far in the future!')
227         
228         gentx = share_info_to_gentx(self.share_info, self.header['target'], tracker, net)
229         
230         if len(gentx['tx_ins'][0]['script']) > 100:
231             raise ValueError('coinbase too large! %i bytes' % (len(gentx['tx_ins'][0]['script']),))
232         
233         if check_merkle_branch(gentx, self.merkle_branch) != self.header['merkle_root']:
234             raise ValueError('''gentx doesn't match header via merkle_branch''')
235         
236         if self.other_txs is not None:
237             if bitcoin_data.merkle_hash([gentx] + self.other_txs) != self.header['merkle_root']:
238                 raise ValueError('''gentx doesn't match header via other_txs''')
239             
240             if len(bitcoin_data.block_type.pack(dict(header=self.header, txs=[gentx] + self.other_txs))) > 1000000 - 1000:
241                 raise ValueError('block size too large')
242     
243     def __repr__(self):
244         return '<Share %s>' % (' '.join('%s=%r' % (k, getattr(self, k)) for k in self.__slots__),)
245
246 class NewShare(Share):
247     __slots__ = 'header previous_block share_info merkle_branch other_txs timestamp share_data new_script subsidy previous_hash previous_share_hash target nonce pow_hash header_hash hash time_seen peer donation'.split(' ')
248     
249     @classmethod
250     def from_share(cls, share, net):
251         if share['type'] == 0:
252             res = cls.from_share1a(new_share1a_type.unpack(share['contents']), net)
253             if not (res.pow_hash > res.header['target']):
254                 raise ValueError('invalid share type')
255             return res
256         elif share['type'] == 1:
257             res = cls.from_share1b(new_share1b_type.unpack(share['contents']), net)
258             if not (res.pow_hash <= res.header['target']):
259                 raise ValueError('invalid share type')
260             return res
261         else:
262             raise ValueError('unknown share type: %r' % (share['type'],))
263     
264     def as_share(self):
265         if self.pow_hash > self.header['target']: # new_share1a
266             return dict(type=0, contents=new_share1a_type.pack(self.as_share1a()))
267         elif self.pow_hash <= self.header['target']: # new_share1b
268             return dict(type=1, contents=new_share1b_type.pack(self.as_share1b()))
269         else:
270             raise AssertionError()
271     
272     def __init__(self, net, header, share_info, merkle_branch=None, other_txs=None):
273         if merkle_branch is None and other_txs is None:
274             raise ValueError('need either merkle_branch or other_txs')
275         if other_txs is not None:
276             new_merkle_branch = bitcoin_data.calculate_merkle_branch([dict(version=0, tx_ins=[], tx_outs=[], lock_time=0)] + other_txs, 0)
277             if merkle_branch is not None:
278                 if merke_branch != new_merkle_branch:
279                     raise ValueError('invalid merkle_branch and other_txs')
280             merkle_branch = new_merkle_branch
281         
282         if len(merkle_branch) > 16:
283             raise ValueError('merkle_branch too long!')
284         
285         self.header = header
286         self.previous_block = header['previous_block']
287         self.share_info = share_info
288         self.merkle_branch = merkle_branch
289         self.other_txs = other_txs
290         
291         self.share_data = self.share_info['new_share_data']
292         self.target = self.share_info['target']
293         
294         self.new_script = self.share_data['new_script']
295         self.subsidy = self.share_data['subsidy']
296         self.timestamp = self.share_data['timestamp']
297         self.donation = self.share_data['donation']
298         
299         if len(self.new_script) > 100:
300             raise ValueError('new_script too long!')
301         
302         self.previous_hash = self.previous_share_hash = self.share_data['previous_share_hash']
303         self.nonce = self.share_data['nonce']
304         
305         if len(self.nonce) > 100:
306             raise ValueError('nonce too long!')
307         
308         if len(self.share_data['coinbase']) > 100:
309             raise ValueError('''coinbase too large! %i bytes''' % (len(self.share_data['coinbase']),))
310         
311         self.pow_hash = net.BITCOIN_POW_FUNC(header)
312         self.header_hash = bitcoin_data.block_header_type.hash256(header)
313         
314         self.hash = new_share1a_type.hash256(self.as_share1a())
315         
316         if self.pow_hash > self.target:
317             print 'hash %x' % self.pow_hash
318             print 'targ %x' % self.target
319             raise ValueError('not enough work!')
320         
321         if script.get_sigop_count(self.new_script) > 1:
322             raise ValueError('too many sigops!')
323         
324         # XXX eww
325         self.time_seen = time.time()
326         self.peer = None
327     
328     def check(self, tracker, now, net):
329         if self.header['timestamp'] < TRANSITION_TIME:
330             raise AssertionError('transitioning...')
331         if self.previous_share_hash is not None:
332             previous_share = tracker.shares[self.previous_share_hash]
333             if not (previous_share.timestamp - 60 <= self.timestamp <= previous_share.timestamp + 60):
334                 raise ValueError('share timestamp (%i) too far from previous timestamp (%i)' % (self.timestamp, previous_share.timestamp))
335         
336         share_info, gentx = new_generate_transaction(tracker, self.share_info['new_share_data'], self.header['target'], net)
337         if share_info != self.share_info:
338             raise ValueError('share difficulty invalid')
339         
340         if bitcoin_data.check_merkle_branch(gentx, 0, self.merkle_branch) != self.header['merkle_root']:
341             raise ValueError('''gentx doesn't match header via merkle_branch''')
342     
343     def as_block(self, tracker, net):
344         if self.other_txs is None:
345             raise ValueError('share does not contain all txs')
346         
347         share_info, gentx = new_generate_transaction(tracker, self.share_info['new_share_data'], self.header['target'], net)
348         assert share_info == self.share_info
349         
350         return dict(header=self.header, txs=[gentx] + self.other_txs)
351
352 def get_pool_attempts_per_second(tracker, previous_share_hash, net, dist=None):
353     if dist is None:
354         dist = net.TARGET_LOOKBEHIND
355     near = tracker.shares[previous_share_hash]
356     far = tracker.shares[tracker.get_nth_parent_hash(previous_share_hash, dist - 1)]
357     attempts = tracker.get_work(near.hash) - tracker.get_work(far.hash)
358     time = near.timestamp - far.timestamp
359     if time == 0:
360         time = 1
361     return attempts//time
362
363 def generate_transaction(tracker, previous_share_hash, new_script, subsidy, nonce, block_target, net):
364     height, last = tracker.get_height_and_last(previous_share_hash)
365     assert height >= net.CHAIN_LENGTH or last is None
366     if height < net.TARGET_LOOKBEHIND:
367         target = bitcoin_data.FloatingInteger.from_target_upper_bound(net.MAX_TARGET)
368     else:
369         attempts_per_second = get_pool_attempts_per_second(tracker, previous_share_hash, net)
370         previous_share = tracker.shares[previous_share_hash] if previous_share_hash is not None else None
371         pre_target = 2**256//(net.SHARE_PERIOD*attempts_per_second) - 1
372         pre_target2 = math.clip(pre_target, (previous_share.target*9//10, previous_share.target*11//10))
373         pre_target3 = math.clip(pre_target2, (0, net.MAX_TARGET))
374         target = bitcoin_data.FloatingInteger.from_target_upper_bound(pre_target3)
375     
376     attempts_to_block = bitcoin_data.target_to_average_attempts(block_target)
377     max_weight = 65535 * net.SPREAD * attempts_to_block
378     
379     this_weight = 65535 * min(bitcoin_data.target_to_average_attempts(target), max_weight)
380     other_weights, other_weights_total, other_donation_weight_total = tracker.get_cumulative_weights(previous_share_hash, min(height, net.CHAIN_LENGTH), max(0, max_weight - this_weight))
381     dest_weights, total_weight, donation_weight_total = math.add_dicts([{new_script: this_weight}, other_weights]), this_weight + other_weights_total, other_donation_weight_total
382     assert total_weight == sum(dest_weights.itervalues()) + donation_weight_total
383     
384     total_weight -= donation_weight_total # ignore donation
385     
386     if net.SCRIPT:
387         amounts = dict((script, subsidy*(396*weight)//(400*total_weight)) for (script, weight) in dest_weights.iteritems())
388         amounts[new_script] = amounts.get(new_script, 0) + subsidy*2//400
389         amounts[net.SCRIPT] = amounts.get(net.SCRIPT, 0) + subsidy*2//400
390         amounts[net.SCRIPT] = amounts.get(net.SCRIPT, 0) + subsidy - sum(amounts.itervalues()) # collect any extra
391     else:
392         amounts = dict((script, subsidy*(398*weight)//(400*total_weight)) for (script, weight) in dest_weights.iteritems())
393         amounts[new_script] = amounts.get(new_script, 0) + subsidy*2//400
394         amounts[new_script] = amounts.get(new_script, 0) + subsidy - sum(amounts.itervalues()) # collect any extra
395     
396     if sum(amounts.itervalues()) != subsidy:
397         raise ValueError()
398     if any(x < 0 for x in amounts.itervalues()):
399         raise ValueError()
400     
401     pre_dests = sorted(amounts.iterkeys(), key=lambda script: (amounts[script], script))
402     pre_dests = pre_dests[-4000:] # block length limit, unlikely to ever be hit
403     
404     dests = sorted(pre_dests, key=lambda script: (script == new_script, script))
405     assert dests[-1] == new_script
406     
407     share_data = dict(
408         previous_share_hash=previous_share_hash,
409         nonce=nonce,
410         target=target,
411     )
412     
413     share_info = dict(
414         share_data=share_data,
415         new_script=new_script,
416         subsidy=subsidy,
417     )
418     
419     return share_info, dict(
420         version=1,
421         tx_ins=[dict(
422             previous_output=None,
423             sequence=None,
424             script=coinbase_type.pack(dict(
425                 identifier=net.IDENTIFIER,
426                 share_data=share_data,
427             )),
428         )],
429         tx_outs=[dict(value=amounts[script], script=script) for script in dests if amounts[script]],
430         lock_time=0,
431     )
432
433 def new_generate_transaction(tracker, new_share_data, block_target, net):
434     previous_share_hash = new_share_data['previous_share_hash']
435     new_script = new_share_data['new_script']
436     subsidy = new_share_data['subsidy']
437     donation = new_share_data['donation']
438     assert 0 <= donation <= 65535
439     
440     if len(new_share_data['coinbase']) > 100:
441         raise ValueError('coinbase too long!')
442     
443     height, last = tracker.get_height_and_last(previous_share_hash)
444     assert height >= net.CHAIN_LENGTH or last is None
445     if height < net.TARGET_LOOKBEHIND:
446         target = bitcoin_data.FloatingInteger.from_target_upper_bound(net.MAX_TARGET)
447     else:
448         attempts_per_second = get_pool_attempts_per_second(tracker, previous_share_hash, net)
449         previous_share = tracker.shares[previous_share_hash] if previous_share_hash is not None else None
450         pre_target = 2**256//(net.SHARE_PERIOD*attempts_per_second) - 1
451         pre_target2 = math.clip(pre_target, (previous_share.target*9//10, previous_share.target*11//10))
452         pre_target3 = math.clip(pre_target2, (0, net.MAX_TARGET))
453         target = bitcoin_data.FloatingInteger.from_target_upper_bound(pre_target3)
454     
455     attempts_to_block = bitcoin_data.target_to_average_attempts(block_target)
456     max_att = net.SPREAD * attempts_to_block
457     
458     this_att = min(bitcoin_data.target_to_average_attempts(target), max_att)
459     other_weights, other_total_weight, other_donation_weight = tracker.get_cumulative_weights(previous_share_hash, min(height, net.CHAIN_LENGTH), 65535*max(0, max_att - this_att))
460     assert other_total_weight == sum(other_weights.itervalues()) + other_donation_weight, (other_total_weight, sum(other_weights.itervalues()) + other_donation_weight)
461     weights, total_weight, donation_weight = math.add_dicts([{new_script: this_att*(65535-donation)}, other_weights]), this_att*65535 + other_total_weight, this_att*donation + other_donation_weight
462     assert total_weight == sum(weights.itervalues()) + donation_weight, (total_weight, sum(weights.itervalues()) + donation_weight)
463     
464     SCRIPT = '4104ffd03de44a6e11b9917f3a29f9443283d9871c9d743ef30d5eddcd37094b64d1b3d8090496b53256786bf5c82932ec23c3b74d9f05a6f95a8b5529352656664bac'.decode('hex')
465     
466     # 1 satoshi is always donated so that a list of p2pool generated blocks can be easily found by looking at the donation address
467     amounts = dict((script, (subsidy-1)*(199*weight)//(200*total_weight)) for (script, weight) in weights.iteritems())
468     amounts[new_script] = amounts.get(new_script, 0) + (subsidy-1)//200
469     amounts[SCRIPT] = amounts.get(SCRIPT, 0) + (subsidy-1)*(199*donation_weight)//(200*total_weight)
470     amounts[SCRIPT] = amounts.get(SCRIPT, 0) + subsidy - sum(amounts.itervalues()) # collect any extra satoshis :P
471     
472     if sum(amounts.itervalues()) != subsidy:
473         raise ValueError()
474     if any(x < 0 for x in amounts.itervalues()):
475         raise ValueError()
476     
477     dests = sorted(amounts.iterkeys(), key=lambda script: (amounts[script], script))
478     dests = dests[-4000:] # block length limit, unlikely to ever be hit
479     
480     share_info = dict(
481         new_share_data=new_share_data,
482         target=target,
483     )
484     
485     return share_info, dict(
486         version=1,
487         tx_ins=[dict(
488             previous_output=None,
489             sequence=None,
490             script=new_share_data['coinbase'].ljust(2, '\x00'),
491         )],
492         tx_outs=[dict(value=0, script='\x20' + bitcoin_data.HashType().pack(new_share_info_type.hash256(share_info)))] + [dict(value=amounts[script], script=script) for script in dests if amounts[script]],
493         lock_time=0,
494     )
495
496
497 class OkayTracker(bitcoin_data.Tracker):
498     def __init__(self, net):
499         bitcoin_data.Tracker.__init__(self)
500         self.net = net
501         self.verified = bitcoin_data.Tracker()
502         self.verified.get_nth_parent_hash = self.get_nth_parent_hash # self is a superset of self.verified
503         
504         self.get_cumulative_weights = skiplists.WeightsSkipList(self)
505     
506     def add(self, share, known_verified=False):
507         bitcoin_data.Tracker.add(self, share)
508         if known_verified:
509             self.verified.add(share)
510     
511     def attempt_verify(self, share, now):
512         if share.hash in self.verified.shares:
513             return True
514         height, last = self.get_height_and_last(share.hash)
515         if height < self.net.CHAIN_LENGTH + 1 and last is not None:
516             raise AssertionError()
517         try:
518             share.check(self, now, self.net)
519         except:
520             log.err(None, 'Share check failed:')
521             return False
522         else:
523             self.verified.add(share)
524             return True
525     
526     def think(self, ht, previous_block, now):
527         desired = set()
528         
529         # O(len(self.heads))
530         #   make 'unverified heads' set?
531         # for each overall head, attempt verification
532         # if it fails, attempt on parent, and repeat
533         # if no successful verification because of lack of parents, request parent
534         bads = set()
535         for head in set(self.heads) - set(self.verified.heads):
536             head_height, last = self.get_height_and_last(head)
537             
538             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))):
539                 if self.attempt_verify(share, now):
540                     break
541                 if share.hash in self.heads:
542                     bads.add(share.hash)
543             else:
544                 if last is not None:
545                     desired.add((self.shares[random.choice(list(self.reverse_shares[last]))].peer, last))
546         for bad in bads:
547             assert bad not in self.verified.shares
548             assert bad in self.heads
549             if p2pool.DEBUG:
550                 print "BAD", bad
551             self.remove(bad)
552         
553         # try to get at least CHAIN_LENGTH height for each verified head, requesting parents if needed
554         for head in list(self.verified.heads):
555             head_height, last_hash = self.verified.get_height_and_last(head)
556             last_height, last_last_hash = self.get_height_and_last(last_hash)
557             # XXX review boundary conditions
558             want = max(self.net.CHAIN_LENGTH - head_height, 0)
559             can = max(last_height - 1 - self.net.CHAIN_LENGTH, 0) if last_last_hash is not None else last_height
560             get = min(want, can)
561             #print 'Z', head_height, last_hash is None, last_height, last_last_hash is None, want, can, get
562             for share in itertools.islice(self.get_chain_known(last_hash), get):
563                 if not self.attempt_verify(share, now):
564                     break
565             if head_height < self.net.CHAIN_LENGTH and last_last_hash is not None:
566                 desired.add((self.verified.shares[random.choice(list(self.verified.reverse_shares[last_hash]))].peer, last_last_hash))
567         
568         # decide best tree
569         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
570         # decide best verified head
571         scores = sorted(self.verified.tails.get(best_tail, []), key=lambda h: (
572             self.verified.get_work(self.verified.get_nth_parent_hash(h, min(5, self.verified.get_height(h)))),
573             #self.verified.shares[h].peer is None,
574             ht.get_min_height(self.verified.shares[h].previous_block),
575             -self.verified.shares[h].time_seen
576         ))
577         
578         
579         if p2pool.DEBUG:
580             print len(self.verified.tails), "chain tails and", len(self.verified.tails.get(best_tail, [])), 'chain heads. Top 10 tails:'
581             if len(scores) > 10:
582                 print '    ...'
583             for h in scores[-10:]:
584                 print '   ', format_hash(h), format_hash(self.verified.shares[h].previous_hash), (
585                     self.verified.get_work(self.verified.get_nth_parent_hash(h, min(5, self.verified.get_height(h)))),
586                     self.verified.shares[h].peer is None,
587                     ht.get_min_height(self.verified.shares[h].previous_block),
588                     -self.verified.shares[h].time_seen
589                 )
590         
591         # eat away at heads
592         if scores:
593             for i in xrange(1000):
594                 to_remove = set()
595                 for share_hash, tail in self.heads.iteritems():
596                     if share_hash in scores[-5:]:
597                         #print 1
598                         continue
599                     if self.shares[share_hash].time_seen > time.time() - 300:
600                         #print 2
601                         continue
602                     if share_hash not in self.verified.shares and max(self.shares[after_tail_hash].time_seen for after_tail_hash in self.reverse_shares.get(tail)) > time.time() - 120: # XXX stupid
603                         #print 3
604                         continue
605                     to_remove.add(share_hash)
606                 if not to_remove:
607                     break
608                 for share_hash in to_remove:
609                     self.remove(share_hash)
610                     if share_hash in self.verified.shares:
611                         self.verified.remove(share_hash)
612                 #print "_________", to_remove
613         
614         # drop tails
615         for i in xrange(1000):
616             to_remove = set()
617             for tail, heads in self.tails.iteritems():
618                 if min(self.get_height(head) for head in heads) < 2*self.net.CHAIN_LENGTH + 10:
619                     continue
620                 for aftertail in self.reverse_shares.get(tail, set()):
621                     if len(self.reverse_shares[self.shares[aftertail].previous_hash]) > 1: # XXX
622                         print "raw"
623                         continue
624                     to_remove.add(aftertail)
625             if not to_remove:
626                 break
627             # if removed from this, it must be removed from verified
628             #start = time.time()
629             for aftertail in to_remove:
630                 if self.shares[aftertail].previous_hash not in self.tails:
631                     print "erk", aftertail, self.shares[aftertail].previous_hash
632                     continue
633                 self.remove(aftertail)
634                 if aftertail in self.verified.shares:
635                     self.verified.remove(aftertail)
636             #end = time.time()
637             #print "removed! %i %f" % (len(to_remove), (end - start)/len(to_remove))
638         
639         best = scores[-1] if scores else None
640         
641         if best is not None:
642             best_share = self.verified.shares[best]
643             if ht.get_min_height(best_share.header['previous_block']) < ht.get_min_height(previous_block) and best_share.header_hash != previous_block and best_share.peer is not None:
644                 if p2pool.DEBUG:
645                     print 'Stale detected! %x < %x' % (best_share.header['previous_block'], previous_block)
646                 best = best_share.previous_hash
647         
648         return best, desired
649     
650     @memoize.memoize_with_backing(expiring_dict.ExpiringDict(5, get_touches=False))
651     def score(self, share_hash, ht):
652         head_height, last = self.verified.get_height_and_last(share_hash)
653         score2 = 0
654         attempts = 0
655         max_height = 0
656         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
657         for share in reversed(list(itertools.islice(self.verified.get_chain_known(share2_hash), self.net.CHAIN_LENGTH))):
658             max_height = max(max_height, ht.get_min_height(share.header['previous_block']))
659             attempts += bitcoin_data.target_to_average_attempts(share.target)
660             this_score = attempts//(ht.get_highest_height() - max_height + 1)
661             if this_score > score2:
662                 score2 = this_score
663         return min(head_height, self.net.CHAIN_LENGTH), score2
664
665 def format_hash(x):
666     if x is None:
667         return 'xxxxxxxx'
668     return '%08x' % (x % 2**32)
669
670 class ShareStore(object):
671     def __init__(self, prefix, net):
672         self.filename = prefix
673         self.dirname = os.path.dirname(os.path.abspath(prefix))
674         self.filename = os.path.basename(os.path.abspath(prefix))
675         self.net = net
676         self.known = None # will be filename -> set of share hashes, set of verified hashes
677     
678     def get_shares(self):
679         if self.known is not None:
680             raise AssertionError()
681         known = {}
682         filenames, next = self.get_filenames_and_next()
683         for filename in filenames:
684             share_hashes, verified_hashes = known.setdefault(filename, (set(), set()))
685             with open(filename, 'rb') as f:
686                 for line in f:
687                     try:
688                         type_id_str, data_hex = line.strip().split(' ')
689                         type_id = int(type_id_str)
690                         if type_id == 0:
691                             share = Share.from_share1a(share1a_type.unpack(data_hex.decode('hex')), self.net)
692                             yield 'share', share
693                             share_hashes.add(share.hash)
694                         elif type_id == 1:
695                             share = Share.from_share1b(share1b_type.unpack(data_hex.decode('hex')), self.net)
696                             yield 'share', share
697                             share_hashes.add(share.hash)
698                         elif type_id == 2:
699                             verified_hash = int(data_hex, 16)
700                             yield 'verified_hash', verified_hash
701                             verified_hashes.add(verified_hash)
702                         elif type_id == 5:
703                             share = NewShare.from_share(new_share_type.unpack(data_hex.decode('hex')), self.net)
704                             yield 'share', share
705                             share_hashes.add(share.hash)
706                         else:
707                             raise NotImplementedError("share type %i" % (type_id,))
708                     except Exception:
709                         log.err(None, "Error while reading saved shares, continuing where left off:")
710         self.known = known
711     
712     def _add_line(self, line):
713         filenames, next = self.get_filenames_and_next()
714         if filenames and os.path.getsize(filenames[-1]) < 10e6:
715             filename = filenames[-1]
716         else:
717             filename = next
718         
719         with open(filename, 'ab') as f:
720             f.write(line + '\n')
721         
722         return filename
723     
724     def add_share(self, share):
725         if isinstance(share, NewShare):
726             type_id, data = 5, new_share_type.pack(share.as_share())
727         elif share.pow_hash <= share.header['target']:
728             type_id, data = 1, share1b_type.pack(share.as_share1b())
729         else:
730             type_id, data = 0, share1a_type.pack(share.as_share1a())
731         filename = self._add_line("%i %s" % (type_id, data.encode('hex')))
732         share_hashes, verified_hashes = self.known.setdefault(filename, (set(), set()))
733         share_hashes.add(share.hash)
734     
735     def add_verified_hash(self, share_hash):
736         filename = self._add_line("%i %x" % (2, share_hash))
737         share_hashes, verified_hashes = self.known.setdefault(filename, (set(), set()))
738         verified_hashes.add(share_hash)
739     
740     def get_filenames_and_next(self):
741         suffixes = sorted(int(x[len(self.filename):]) for x in os.listdir(self.dirname) if x.startswith(self.filename) and x[len(self.filename):].isdigit())
742         return [os.path.join(self.dirname, self.filename + str(suffix)) for suffix in suffixes], os.path.join(self.dirname, self.filename + (str(suffixes[-1] + 1) if suffixes else str(0)))
743     
744     def forget_share(self, share_hash):
745         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
746             if share_hash in share_hashes:
747                 share_hashes.remove(share_hash)
748         self.check_remove()
749     
750     def forget_verified_share(self, share_hash):
751         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
752             if share_hash in verified_hashes:
753                 verified_hashes.remove(share_hash)
754         self.check_remove()
755     
756     def check_remove(self):
757         to_remove = set()
758         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
759             #print filename, len(share_hashes) + len(verified_hashes)
760             if not share_hashes and not verified_hashes:
761                 to_remove.add(filename)
762         for filename in to_remove:
763             self.known.pop(filename)
764             os.remove(filename)
765             print "REMOVED", filename
766
767 class BitcoinMainnet(networks.BitcoinMainnet):
768     SHARE_PERIOD = 10 # seconds
769     CHAIN_LENGTH = 24*60*60//5 # shares
770     TARGET_LOOKBEHIND = 200 # shares
771     SPREAD = 3 # blocks
772     SCRIPT = '4104ffd03de44a6e11b9917f3a29f9443283d9871c9d743ef30d5eddcd37094b64d1b3d8090496b53256786bf5c82932ec23c3b74d9f05a6f95a8b5529352656664bac'.decode('hex')
773     IDENTIFIER = 'fc70035c7a81bc6f'.decode('hex')
774     PREFIX = '2472ef181efcd37b'.decode('hex')
775     NAME = 'bitcoin'
776     P2P_PORT = 9333
777     MAX_TARGET = 2**256//2**32 - 1
778     PERSIST = False
779     WORKER_PORT = 9332
780
781 class BitcoinTestnet(networks.BitcoinTestnet):
782     SHARE_PERIOD = 1 # seconds
783     CHAIN_LENGTH = 24*60*60//5 # shares
784     TARGET_LOOKBEHIND = 200 # shares
785     SPREAD = 3 # blocks
786     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
787     IDENTIFIER = '5fc2be2d4f0d6bfb'.decode('hex')
788     PREFIX = '3f6057a15036f441'.decode('hex')
789     NAME = 'bitcoin_testnet'
790     P2P_PORT = 19333
791     MAX_TARGET = 2**256//2**32 - 1
792     PERSIST = False
793     WORKER_PORT = 19332
794
795 class NamecoinMainnet(networks.NamecoinMainnet):
796     SHARE_PERIOD = 10 # seconds
797     CHAIN_LENGTH = 24*60*60//10 # shares
798     TARGET_LOOKBEHIND = 3600//10 # shares
799     SPREAD = 3 # blocks
800     SCRIPT = '41043da5beb73f8f18cede1a41b0ed953123f1342b8e0216ab5bf71ed3e024201b4017f472bddb6041f17978d89ed8f8ed84f9e726b0bca80cacf96347c7153e8df0ac'.decode('hex')
801     IDENTIFIER = 'd5b1192062c4c454'.decode('hex')
802     PREFIX = 'b56f3d0fb24fc982'.decode('hex')
803     NAME = 'namecoin'
804     P2P_PORT = 9334
805     MAX_TARGET = 2**256//2**32 - 1
806     PERSIST = True
807     WORKER_PORT = 9331
808
809 class NamecoinTestnet(networks.NamecoinTestnet):
810     SHARE_PERIOD = 1 # seconds
811     CHAIN_LENGTH = 24*60*60//5 # shares
812     TARGET_LOOKBEHIND = 200 # shares
813     SPREAD = 3 # blocks
814     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
815     IDENTIFIER = '8dd303d014a01a60'.decode('hex')
816     PREFIX = '4d6581d24f51acbf'.decode('hex')
817     NAME = 'namecoin_testnet'
818     P2P_PORT = 19334
819     MAX_TARGET = 2**256//2**20 - 1
820     PERSIST = False
821     WORKER_PORT = 19331
822
823 class IxcoinMainnet(networks.IxcoinMainnet):
824     SHARE_PERIOD = 10 # seconds
825     CHAIN_LENGTH = 24*60*60//10 # shares
826     TARGET_LOOKBEHIND = 3600//10 # shares
827     SPREAD = 3 # blocks
828     SCRIPT = '41043da5beb73f8f18cede1a41b0ed953123f1342b8e0216ab5bf71ed3e024201b4017f472bddb6041f17978d89ed8f8ed84f9e726b0bca80cacf96347c7153e8df0ac'.decode('hex')
829     IDENTIFIER = '27b564116e2a2666'.decode('hex')
830     PREFIX = '9dd6c4a619401f2f'.decode('hex')
831     NAME = 'ixcoin'
832     P2P_PORT = 9335
833     MAX_TARGET = 2**256//2**32 - 1
834     PERSIST = True
835     WORKER_PORT = 9330
836
837 class IxcoinTestnet(networks.IxcoinTestnet):
838     SHARE_PERIOD = 1 # seconds
839     CHAIN_LENGTH = 24*60*60//5 # shares
840     TARGET_LOOKBEHIND = 200 # shares
841     SPREAD = 3 # blocks
842     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
843     IDENTIFIER = '7430cbeb01249e44'.decode('hex')
844     PREFIX = '7cfffda946709c1f'.decode('hex')
845     NAME = 'ixcoin_testnet'
846     P2P_PORT = 19335
847     MAX_TARGET = 2**256//2**20 - 1
848     PERSIST = False
849     WORKER_PORT = 19330
850
851 class I0coinMainnet(networks.I0coinMainnet):
852     SHARE_PERIOD = 10 # seconds
853     CHAIN_LENGTH = 24*60*60//10 # shares
854     TARGET_LOOKBEHIND = 3600//10 # shares
855     SPREAD = 3 # blocks
856     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
857     IDENTIFIER = 'b32e3f10c2ff221b'.decode('hex')
858     PREFIX = '6155537ed977a3b5'.decode('hex')
859     NAME = 'i0coin'
860     P2P_PORT = 9336
861     MAX_TARGET = 2**256//2**32 - 1
862     PERSIST = False
863     WORKER_PORT = 9329
864
865 class I0coinTestnet(networks.I0coinTestnet):
866     SHARE_PERIOD = 1 # seconds
867     CHAIN_LENGTH = 24*60*60//5 # shares
868     TARGET_LOOKBEHIND = 200 # shares
869     SPREAD = 3 # blocks
870     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
871     IDENTIFIER = '7712c1a8181b5f2e'.decode('hex')
872     PREFIX = '792d2e7d770fbe68'.decode('hex')
873     NAME = 'i0coin_testnet'
874     P2P_PORT = 19336
875     MAX_TARGET = 2**256//2**20 - 1
876     PERSIST = False
877     WORKER_PORT = 19329
878
879 class SolidcoinMainnet(networks.SolidcoinMainnet):
880     SHARE_PERIOD = 10
881     CHAIN_LENGTH = 24*60*60//10 # shares
882     TARGET_LOOKBEHIND = 3600//10 # shares
883     SPREAD = 3 # blocks
884     SCRIPT = bitcoin_data.pubkey_hash_to_script2(bitcoin_data.address_to_pubkey_hash('sMKZ1yxHETxPYKh4Z2anWnwZDJZU7ztroy', networks.SolidcoinMainnet))
885     IDENTIFIER = '9cc9c421cca258cd'.decode('hex')
886     PREFIX = 'c059125b8070f00a'.decode('hex')
887     NAME = 'solidcoin'
888     P2P_PORT = 9337
889     MAX_TARGET = 2**256//2**32 - 1
890     PERSIST = True
891     WORKER_PORT = 9328
892
893 class LitecoinMainnet(networks.LitecoinMainnet):
894     SHARE_PERIOD = 10 # seconds
895     CHAIN_LENGTH = 24*60*60//5 # shares
896     TARGET_LOOKBEHIND = 200 # shares
897     SPREAD = 12 # blocks
898     SCRIPT = None # no fee
899     IDENTIFIER = 'e037d5b8c6923410'.decode('hex')
900     PREFIX = '7208c1a53ef629b0'.decode('hex')
901     NAME = 'litecoin'
902     P2P_PORT = 9338
903     MAX_TARGET = 2**256//2**20 - 1
904     PERSIST = True
905     WORKER_PORT = 9327
906
907 class LitecoinTestnet(networks.LitecoinTestnet):
908     SHARE_PERIOD = 1 # seconds
909     CHAIN_LENGTH = 24*60*60//5 # shares
910     TARGET_LOOKBEHIND = 200 # shares
911     SPREAD = 12 # blocks
912     SCRIPT = None # no fee
913     IDENTIFIER = 'cca5e24ec6408b1e'.decode('hex')
914     PREFIX = 'ad9614f6466a39cf'.decode('hex')
915     NAME = 'litecoin_testnet'
916     P2P_PORT = 19338
917     MAX_TARGET = 2**256//2**17 - 1
918     PERSIST = False
919     WORKER_PORT = 19327
920
921 nets = dict((net.NAME, net) for net in set([BitcoinMainnet, BitcoinTestnet, NamecoinMainnet, NamecoinTestnet, IxcoinMainnet, IxcoinTestnet, I0coinMainnet, I0coinTestnet, SolidcoinMainnet, LitecoinMainnet, LitecoinTestnet]))