tahoe-lafs/src/allmydata/mutable.py

1859 lines
78 KiB
Python

import os, struct, time, weakref
from itertools import islice, count
from zope.interface import implements
from twisted.internet import defer
from twisted.python import failure
from twisted.application import service
from foolscap.eventual import eventually
from allmydata.interfaces import IMutableFileNode, IMutableFileURI, \
IPublishStatus, IRetrieveStatus
from allmydata.util import base32, hashutil, mathutil, idlib, log
from allmydata.uri import WriteableSSKFileURI
from allmydata import hashtree, codec, storage
from allmydata.encode import NotEnoughPeersError
from pycryptopp.publickey import rsa
from pycryptopp.cipher.aes import AES
class NotMutableError(Exception):
pass
class NeedMoreDataError(Exception):
def __init__(self, needed_bytes, encprivkey_offset, encprivkey_length):
Exception.__init__(self)
self.needed_bytes = needed_bytes # up through EOF
self.encprivkey_offset = encprivkey_offset
self.encprivkey_length = encprivkey_length
def __str__(self):
return "<NeedMoreDataError (%d bytes)>" % self.needed_bytes
class UncoordinatedWriteError(Exception):
def __repr__(self):
return "<%s -- You, oh user, tried to change a file or directory at the same time as another process was trying to change it. To avoid data loss, don't do this. Please see docs/write_coordination.html for details.>" % (self.__class__.__name__,)
class CorruptShareError(Exception):
def __init__(self, peerid, shnum, reason):
self.args = (peerid, shnum, reason)
self.peerid = peerid
self.shnum = shnum
self.reason = reason
def __str__(self):
short_peerid = idlib.nodeid_b2a(self.peerid)[:8]
return "<CorruptShareError peerid=%s shnum[%d]: %s" % (short_peerid,
self.shnum,
self.reason)
PREFIX = ">BQ32s16s" # each version has a different prefix
SIGNED_PREFIX = ">BQ32s16s BBQQ" # this is covered by the signature
HEADER = ">BQ32s16s BBQQ LLLLQQ" # includes offsets
HEADER_LENGTH = struct.calcsize(HEADER)
def unpack_prefix_and_signature(data):
assert len(data) >= HEADER_LENGTH
o = {}
prefix = data[:struct.calcsize(SIGNED_PREFIX)]
(version,
seqnum,
root_hash,
IV,
k, N, segsize, datalen,
o['signature'],
o['share_hash_chain'],
o['block_hash_tree'],
o['share_data'],
o['enc_privkey'],
o['EOF']) = struct.unpack(HEADER, data[:HEADER_LENGTH])
assert version == 0
if len(data) < o['share_hash_chain']:
raise NeedMoreDataError(o['share_hash_chain'],
o['enc_privkey'], o['EOF']-o['enc_privkey'])
pubkey_s = data[HEADER_LENGTH:o['signature']]
signature = data[o['signature']:o['share_hash_chain']]
return (seqnum, root_hash, IV, k, N, segsize, datalen,
pubkey_s, signature, prefix)
def unpack_share(data):
assert len(data) >= HEADER_LENGTH
o = {}
(version,
seqnum,
root_hash,
IV,
k, N, segsize, datalen,
o['signature'],
o['share_hash_chain'],
o['block_hash_tree'],
o['share_data'],
o['enc_privkey'],
o['EOF']) = struct.unpack(HEADER, data[:HEADER_LENGTH])
assert version == 0
if len(data) < o['EOF']:
raise NeedMoreDataError(o['EOF'],
o['enc_privkey'], o['EOF']-o['enc_privkey'])
pubkey = data[HEADER_LENGTH:o['signature']]
signature = data[o['signature']:o['share_hash_chain']]
share_hash_chain_s = data[o['share_hash_chain']:o['block_hash_tree']]
share_hash_format = ">H32s"
hsize = struct.calcsize(share_hash_format)
assert len(share_hash_chain_s) % hsize == 0, len(share_hash_chain_s)
share_hash_chain = []
for i in range(0, len(share_hash_chain_s), hsize):
chunk = share_hash_chain_s[i:i+hsize]
(hid, h) = struct.unpack(share_hash_format, chunk)
share_hash_chain.append( (hid, h) )
share_hash_chain = dict(share_hash_chain)
block_hash_tree_s = data[o['block_hash_tree']:o['share_data']]
assert len(block_hash_tree_s) % 32 == 0, len(block_hash_tree_s)
block_hash_tree = []
for i in range(0, len(block_hash_tree_s), 32):
block_hash_tree.append(block_hash_tree_s[i:i+32])
share_data = data[o['share_data']:o['enc_privkey']]
enc_privkey = data[o['enc_privkey']:o['EOF']]
return (seqnum, root_hash, IV, k, N, segsize, datalen,
pubkey, signature, share_hash_chain, block_hash_tree,
share_data, enc_privkey)
def unpack_share_data(data):
assert len(data) >= HEADER_LENGTH
o = {}
(version,
seqnum,
root_hash,
IV,
k, N, segsize, datalen,
o['signature'],
o['share_hash_chain'],
o['block_hash_tree'],
o['share_data'],
o['enc_privkey'],
o['EOF']) = struct.unpack(HEADER, data[:HEADER_LENGTH])
assert version == 0
if len(data) < o['enc_privkey']:
raise NeedMoreDataError(o['enc_privkey'],
o['enc_privkey'], o['EOF']-o['enc_privkey'])
pubkey = data[HEADER_LENGTH:o['signature']]
signature = data[o['signature']:o['share_hash_chain']]
share_hash_chain_s = data[o['share_hash_chain']:o['block_hash_tree']]
share_hash_format = ">H32s"
hsize = struct.calcsize(share_hash_format)
assert len(share_hash_chain_s) % hsize == 0, len(share_hash_chain_s)
share_hash_chain = []
for i in range(0, len(share_hash_chain_s), hsize):
chunk = share_hash_chain_s[i:i+hsize]
(hid, h) = struct.unpack(share_hash_format, chunk)
share_hash_chain.append( (hid, h) )
share_hash_chain = dict(share_hash_chain)
block_hash_tree_s = data[o['block_hash_tree']:o['share_data']]
assert len(block_hash_tree_s) % 32 == 0, len(block_hash_tree_s)
block_hash_tree = []
for i in range(0, len(block_hash_tree_s), 32):
block_hash_tree.append(block_hash_tree_s[i:i+32])
share_data = data[o['share_data']:o['enc_privkey']]
return (seqnum, root_hash, IV, k, N, segsize, datalen,
pubkey, signature, share_hash_chain, block_hash_tree,
share_data)
def pack_checkstring(seqnum, root_hash, IV):
return struct.pack(PREFIX,
0, # version,
seqnum,
root_hash,
IV)
def unpack_checkstring(checkstring):
cs_len = struct.calcsize(PREFIX)
version, seqnum, root_hash, IV = struct.unpack(PREFIX, checkstring[:cs_len])
assert version == 0 # TODO: just ignore the share
return (seqnum, root_hash, IV)
def pack_prefix(seqnum, root_hash, IV,
required_shares, total_shares,
segment_size, data_length):
prefix = struct.pack(SIGNED_PREFIX,
0, # version,
seqnum,
root_hash,
IV,
required_shares,
total_shares,
segment_size,
data_length,
)
return prefix
def pack_offsets(verification_key_length, signature_length,
share_hash_chain_length, block_hash_tree_length,
share_data_length, encprivkey_length):
post_offset = HEADER_LENGTH
offsets = {}
o1 = offsets['signature'] = post_offset + verification_key_length
o2 = offsets['share_hash_chain'] = o1 + signature_length
o3 = offsets['block_hash_tree'] = o2 + share_hash_chain_length
o4 = offsets['share_data'] = o3 + block_hash_tree_length
o5 = offsets['enc_privkey'] = o4 + share_data_length
o6 = offsets['EOF'] = o5 + encprivkey_length
return struct.pack(">LLLLQQ",
offsets['signature'],
offsets['share_hash_chain'],
offsets['block_hash_tree'],
offsets['share_data'],
offsets['enc_privkey'],
offsets['EOF'])
def pack_share(prefix, verification_key, signature,
share_hash_chain, block_hash_tree,
share_data, encprivkey):
share_hash_chain_s = "".join([struct.pack(">H32s", i, share_hash_chain[i])
for i in sorted(share_hash_chain.keys())])
for h in block_hash_tree:
assert len(h) == 32
block_hash_tree_s = "".join(block_hash_tree)
offsets = pack_offsets(len(verification_key),
len(signature),
len(share_hash_chain_s),
len(block_hash_tree_s),
len(share_data),
len(encprivkey))
final_share = "".join([prefix,
offsets,
verification_key,
signature,
share_hash_chain_s,
block_hash_tree_s,
share_data,
encprivkey])
return final_share
class RetrieveStatus:
implements(IRetrieveStatus)
statusid_counter = count(0)
def __init__(self):
self.timings = {}
self.timings["fetch_per_server"] = {}
self.timings["cumulative_verify"] = 0.0
self.sharemap = {}
self.problems = {}
self.active = True
self.storage_index = None
self.helper = False
self.encoding = ("?","?")
self.search_distance = None
self.size = None
self.status = "Not started"
self.progress = 0.0
self.counter = self.statusid_counter.next()
self.started = time.time()
def get_started(self):
return self.started
def get_storage_index(self):
return self.storage_index
def get_encoding(self):
return self.encoding
def get_search_distance(self):
return self.search_distance
def using_helper(self):
return self.helper
def get_size(self):
return self.size
def get_status(self):
return self.status
def get_progress(self):
return self.progress
def get_active(self):
return self.active
def get_counter(self):
return self.counter
def set_storage_index(self, si):
self.storage_index = si
def set_helper(self, helper):
self.helper = helper
def set_encoding(self, k, n):
self.encoding = (k, n)
def set_search_distance(self, value):
self.search_distance = value
def set_size(self, size):
self.size = size
def set_status(self, status):
self.status = status
def set_progress(self, value):
self.progress = value
def set_active(self, value):
self.active = value
class Retrieve:
def __init__(self, filenode):
self._node = filenode
self._contents = None
# if the filenode already has a copy of the pubkey, use it. Otherwise
# we'll grab a copy from the first peer we talk to.
self._pubkey = filenode.get_pubkey()
self._storage_index = filenode.get_storage_index()
self._readkey = filenode.get_readkey()
self._last_failure = None
self._log_number = None
self._log_prefix = prefix = storage.si_b2a(self._storage_index)[:5]
num = self._node._client.log("Retrieve(%s): starting" % prefix)
self._log_number = num
self._status = RetrieveStatus()
self._status.set_storage_index(self._storage_index)
self._status.set_helper(False)
self._status.set_progress(0.0)
self._status.set_active(True)
def log(self, msg, **kwargs):
prefix = self._log_prefix
num = self._node._client.log("Retrieve(%s): %s" % (prefix, msg),
parent=self._log_number, **kwargs)
return num
def log_err(self, f):
num = log.err(f, parent=self._log_number)
return num
def retrieve(self):
"""Retrieve the filenode's current contents. Returns a Deferred that
fires with a string when the contents have been retrieved."""
# 1: make a guess as to how many peers we should send requests to. We
# want to hear from k+EPSILON (k because we have to, EPSILON extra
# because that helps us resist rollback attacks). [TRADEOFF:
# EPSILON>0 means extra work] [TODO: implement EPSILON>0]
# 2: build the permuted peerlist, taking the first k+E peers
# 3: send readv requests to all of them in parallel, asking for the
# first 2KB of data from all shares
# 4: when the first of the responses comes back, extract information:
# 4a: extract the pubkey, hash it, compare against the URI. If this
# check fails, log a WEIRD and ignore the peer.
# 4b: extract the prefix (seqnum, roothash, k, N, segsize, datalength)
# and verify the signature on it. If this is wrong, log a WEIRD
# and ignore the peer. Save the prefix string in a dict that's
# keyed by (seqnum,roothash) and has (prefixstring, sharemap) as
# values. We'll use the prefixstring again later to avoid doing
# multiple signature checks
# 4c: extract the share size (offset of the last byte of sharedata).
# if it is larger than 2k, send new readv requests to pull down
# the extra data
# 4d: if the extracted 'k' is more than we guessed, rebuild a larger
# permuted peerlist and send out more readv requests.
# 5: as additional responses come back, extract the prefix and compare
# against the ones we've already seen. If they match, add the
# peerid to the corresponing sharemap dict
# 6: [TRADEOFF]: if EPSILON==0, when we get k responses for the
# same (seqnum,roothash) key, attempt to reconstruct that data.
# if EPSILON>0, wait for k+EPSILON responses, then attempt to
# reconstruct the most popular version.. If we do not have enough
# shares and there are still requests outstanding, wait. If there
# are not still requests outstanding (todo: configurable), send
# more requests. Never send queries to more than 2*N servers. If
# we've run out of servers, fail.
# 7: if we discover corrupt shares during the reconstruction process,
# remove that share from the sharemap. and start step#6 again.
initial_query_count = 5
# how much data should be read on the first fetch? It would be nice
# if we could grab small directories in a single RTT. The way we pack
# dirnodes consumes about 112 bytes per child. The way we pack
# mutable files puts about 935 bytes of pubkey+sig+hashes, then our
# data, then about 1216 bytes of encprivkey. So 2kB ought to get us
# about 9 entries, which seems like a good default.
self._read_size = 2000
# we might not know how many shares we need yet.
self._required_shares = self._node.get_required_shares()
self._total_shares = self._node.get_total_shares()
# self._valid_versions is a dictionary in which the keys are
# 'verinfo' tuples (seqnum, root_hash, IV). Every time we hear about
# a new potential version of the file, we check its signature, and
# the valid ones are added to this dictionary. The values of the
# dictionary are (prefix, sharemap) tuples, where 'prefix' is just
# the first part of the share (containing the serialized verinfo),
# for easier comparison. 'sharemap' is a DictOfSets, in which the
# keys are sharenumbers, and the values are sets of (peerid, data)
# tuples. There is a (peerid, data) tuple for every instance of a
# given share that we've seen. The 'data' in this tuple is a full
# copy of the SDMF share, starting with the \x00 version byte and
# continuing through the last byte of sharedata.
self._valid_versions = {}
# self._valid_shares is a dict mapping (peerid,data) tuples to
# validated sharedata strings. Each time we examine the hash chains
# inside a share and validate them against a signed root_hash, we add
# the share to self._valid_shares . We use this to avoid re-checking
# the hashes over and over again.
self._valid_shares = {}
self._started = time.time()
self._done_deferred = defer.Deferred()
d = defer.succeed(initial_query_count)
d.addCallback(self._choose_initial_peers)
d.addCallback(self._send_initial_requests)
d.addCallback(self._wait_for_finish)
return d
def _wait_for_finish(self, res):
return self._done_deferred
def _choose_initial_peers(self, numqueries):
n = self._node
started = time.time()
full_peerlist = n._client.get_permuted_peers("storage",
self._storage_index)
# _peerlist is a list of (peerid,conn) tuples for peers that are
# worth talking too. This starts with the first numqueries in the
# permuted list. If that's not enough to get us a recoverable
# version, we expand this to include the first 2*total_shares peerids
# (assuming we learn what total_shares is from one of the first
# numqueries peers)
self._peerlist = [p for p in islice(full_peerlist, numqueries)]
# _peerlist_limit is the query limit we used to build this list. If
# we later increase this limit, it may be useful to re-scan the
# permuted list.
self._peerlist_limit = numqueries
self._status.set_search_distance(len(self._peerlist))
elapsed = time.time() - started
self._status.timings["peer_selection"] = elapsed
return self._peerlist
def _send_initial_requests(self, peerlist):
self._first_query_sent = time.time()
self._bad_peerids = set()
self._running = True
self._queries_outstanding = set()
self._used_peers = set()
self._sharemap = DictOfSets() # shnum -> [(peerid, seqnum, R)..]
dl = []
for (peerid, ss) in peerlist:
self._queries_outstanding.add(peerid)
self._do_query(ss, peerid, self._storage_index, self._read_size)
# control flow beyond this point: state machine. Receiving responses
# from queries is the input. We might send out more queries, or we
# might produce a result.
return None
def _do_query(self, ss, peerid, storage_index, readsize):
started = time.time()
self._queries_outstanding.add(peerid)
d = ss.callRemote("slot_readv", storage_index, [], [(0, readsize)])
d.addCallback(self._got_results, peerid, readsize, (ss, storage_index),
started)
d.addErrback(self._query_failed, peerid)
# errors that aren't handled by _query_failed (and errors caused by
# _query_failed) get logged, but we still want to check for doneness.
d.addErrback(log.err)
d.addBoth(self._check_for_done)
return d
def _deserialize_pubkey(self, pubkey_s):
verifier = rsa.create_verifying_key_from_string(pubkey_s)
return verifier
def _got_results(self, datavs, peerid, readsize, stuff, started):
self._queries_outstanding.discard(peerid)
self._used_peers.add(peerid)
if not self._running:
return
elapsed = time.time() - started
if peerid not in self._status.timings["fetch_per_server"]:
self._status.timings["fetch_per_server"][peerid] = []
self._status.timings["fetch_per_server"][peerid].append(elapsed)
if peerid not in self._status.sharemap:
self._status.sharemap[peerid] = set()
for shnum,datav in datavs.items():
data = datav[0]
try:
self._got_results_one_share(shnum, data, peerid)
except NeedMoreDataError, e:
# ah, just re-send the query then.
self.log("need more data from %(peerid)s, got %(got)d, need %(needed)d",
peerid=idlib.shortnodeid_b2a(peerid),
got=len(data), needed=e.needed_bytes,
level=log.NOISY)
self._read_size = max(self._read_size, e.needed_bytes)
# TODO: for MDMF, sanity-check self._read_size: don't let one
# server cause us to try to read gigabytes of data from all
# other servers.
(ss, storage_index) = stuff
self._do_query(ss, peerid, storage_index, self._read_size)
return
except CorruptShareError, e:
# log it and give the other shares a chance to be processed
f = failure.Failure()
self.log("bad share: %s %s" % (f, f.value), level=log.WEIRD)
self._bad_peerids.add(peerid)
self._last_failure = f
pass
# all done!
def _got_results_one_share(self, shnum, data, peerid):
self.log("_got_results: got shnum #%d from peerid %s"
% (shnum, idlib.shortnodeid_b2a(peerid)))
(seqnum, root_hash, IV, k, N, segsize, datalength,
# this might raise NeedMoreDataError, in which case the rest of
# the shares are probably short too. _query_failed() will take
# responsiblity for re-issuing the queries with a new length.
pubkey_s, signature, prefix) = unpack_prefix_and_signature(data)
if not self._pubkey:
fingerprint = hashutil.ssk_pubkey_fingerprint_hash(pubkey_s)
assert len(fingerprint) == 32
if fingerprint != self._node._fingerprint:
self._status.problems[peerid] = "sh#%d: pubkey doesn't match fingerprint" % shnum
raise CorruptShareError(peerid, shnum,
"pubkey doesn't match fingerprint")
self._pubkey = self._deserialize_pubkey(pubkey_s)
self._node._populate_pubkey(self._pubkey)
verinfo = (seqnum, root_hash, IV, segsize, datalength)
self._status.sharemap[peerid].add(verinfo)
if verinfo not in self._valid_versions:
# it's a new pair. Verify the signature.
started = time.time()
valid = self._pubkey.verify(prefix, signature)
# this records the total verification time for all versions we've
# seen. This time is included in "fetch".
elapsed = time.time() - started
self._status.timings["cumulative_verify"] += elapsed
if not valid:
self._status.problems[peerid] = "sh#%d: invalid signature" % shnum
raise CorruptShareError(peerid, shnum,
"signature is invalid")
# ok, it's a valid verinfo. Add it to the list of validated
# versions.
self.log(" found valid version %d-%s from %s-sh%d: %d-%d/%d/%d"
% (seqnum, base32.b2a(root_hash)[:4],
idlib.shortnodeid_b2a(peerid), shnum,
k, N, segsize, datalength))
self._valid_versions[verinfo] = (prefix, DictOfSets())
# and make a note of the other parameters we've just learned
# NOTE: Retrieve needs to be refactored to put k,N in the verinfo
# along with seqnum/etc, to make sure we don't co-mingle shares
# from differently-encoded versions of the same file.
if self._required_shares is None:
self._required_shares = k
self._node._populate_required_shares(k)
if self._total_shares is None:
self._total_shares = N
self._node._populate_total_shares(N)
# reject shares that don't match our narrow-minded ideas of what
# encoding we're going to use. This addresses the immediate needs of
# ticket #312, by turning the data corruption into unavailability. To
# get back the availability (i.e. make sure that one weird-encoding
# share that happens to come back first doesn't make us ignore the
# rest of the shares), we need to implement the refactoring mentioned
# above.
if k != self._required_shares:
self._status.problems[peerid] = "sh#%d: k=%d, we want %d" \
% (shnum, k, self._required_shares)
raise CorruptShareError(peerid, shnum,
"share has k=%d, we want k=%d" %
(k, self._required_shares))
if N != self._total_shares:
self._status.problems[peerid] = "sh#%d: N=%d, we want %d" \
% (shnum, N, self._total_shares)
raise CorruptShareError(peerid, shnum,
"share has N=%d, we want N=%d" %
(N, self._total_shares))
# we've already seen this pair, and checked the signature so we
# know it's a valid candidate. Accumulate the share info, if
# there's enough data present. If not, raise NeedMoreDataError,
# which will trigger a re-fetch.
_ignored = unpack_share_data(data)
self.log(" found enough data to add share contents")
self._valid_versions[verinfo][1].add(shnum, (peerid, data))
def _query_failed(self, f, peerid):
if not self._running:
return
self._queries_outstanding.discard(peerid)
self._used_peers.add(peerid)
self._last_failure = f
self._bad_peerids.add(peerid)
self.log("error during query: %s %s" % (f, f.value), level=log.WEIRD)
def _check_for_done(self, res):
if not self._running:
self.log("ODD: _check_for_done but we're not running")
return
share_prefixes = {}
versionmap = DictOfSets()
for verinfo, (prefix, sharemap) in self._valid_versions.items():
# sharemap is a dict that maps shnums to sets of (peerid,data).
# len(sharemap) is the number of distinct shares that appear to
# be available.
if len(sharemap) >= self._required_shares:
# this one looks retrievable. TODO: our policy of decoding
# the first version that we can get is a bit troublesome: in
# a small grid with a large expansion factor, a single
# out-of-date server can cause us to retrieve an older
# version. Fixing this is equivalent to protecting ourselves
# against a rollback attack, and the best approach is
# probably to say that we won't do _attempt_decode until:
# (we've received at least k+EPSILON shares or
# we've received at least k shares and ran out of servers)
# in that case, identify the verinfos that are decodeable and
# attempt the one with the highest (seqnum,R) value. If the
# highest seqnum can't be recovered, only then might we fall
# back to an older version.
d = defer.maybeDeferred(self._attempt_decode, verinfo, sharemap)
def _problem(f):
self._last_failure = f
if f.check(CorruptShareError):
self.log("saw corrupt share, rescheduling",
level=log.WEIRD)
# _attempt_decode is responsible for removing the bad
# share, so we can just try again
eventually(self._check_for_done, None)
return
return f
d.addCallbacks(self._done, _problem)
# TODO: create an errback-routing mechanism to make sure that
# weird coding errors will cause the retrieval to fail rather
# than hanging forever. Any otherwise-unhandled exceptions
# should follow this path. A simple way to test this is to
# raise BadNameError in _validate_share_and_extract_data .
return
# we don't have enough shares yet. Should we send out more queries?
if self._queries_outstanding:
# there are some running, so just wait for them to come back.
# TODO: if our initial guess at k was too low, waiting for these
# responses before sending new queries will increase our latency,
# so we could speed things up by sending new requests earlier.
self.log("ROUTINE: %d queries outstanding" %
len(self._queries_outstanding))
return
# no more queries are outstanding. Can we send out more? First,
# should we be looking at more peers?
self.log("need more peers: N=%s, peerlist=%d peerlist_limit=%d" %
(self._total_shares, len(self._peerlist),
self._peerlist_limit), level=log.UNUSUAL)
if self._total_shares is not None:
search_distance = self._total_shares * 2
else:
search_distance = 20
self.log("search_distance=%d" % search_distance, level=log.UNUSUAL)
if self._peerlist_limit < search_distance:
# we might be able to get some more peers from the list
peers = self._node._client.get_permuted_peers("storage",
self._storage_index)
self._peerlist = [p for p in islice(peers, search_distance)]
self._peerlist_limit = search_distance
self.log("added peers, peerlist=%d, peerlist_limit=%d"
% (len(self._peerlist), self._peerlist_limit),
level=log.UNUSUAL)
# are there any peers on the list that we haven't used?
new_query_peers = []
peer_indicies = []
for i, (peerid, ss) in enumerate(self._peerlist):
if peerid not in self._used_peers:
new_query_peers.append( (peerid, ss) )
peer_indicies.append(i)
if len(new_query_peers) > 5:
# only query in batches of 5. TODO: this is pretty
# arbitrary, really I want this to be something like
# k - max(known_version_sharecounts) + some extra
break
new_search_distance = max(max(peer_indicies),
self._status.get_search_distance())
self._status.set_search_distance(new_search_distance)
if new_query_peers:
self.log("sending %d new queries (read %d bytes)" %
(len(new_query_peers), self._read_size), level=log.UNUSUAL)
for (peerid, ss) in new_query_peers:
self._do_query(ss, peerid, self._storage_index, self._read_size)
# we'll retrigger when those queries come back
return
# we've used up all the peers we're allowed to search. Failure.
self.log("ran out of peers", level=log.WEIRD)
e = NotEnoughPeersError("last failure: %s" % self._last_failure)
return self._done(failure.Failure(e))
def _attempt_decode(self, verinfo, sharemap):
# sharemap is a dict which maps shnum to [(peerid,data)..] sets.
(seqnum, root_hash, IV, segsize, datalength) = verinfo
assert len(sharemap) >= self._required_shares, len(sharemap)
shares_s = []
for shnum in sorted(sharemap.keys()):
for shareinfo in sharemap[shnum]:
shares_s.append("#%d" % shnum)
shares_s = ",".join(shares_s)
self.log("_attempt_decode: version %d-%s, shares: %s" %
(seqnum, base32.b2a(root_hash)[:4], shares_s))
# first, validate each share that we haven't validated yet. We use
# self._valid_shares to remember which ones we've already checked.
shares = {}
for shnum, shareinfos in sharemap.items():
assert len(shareinfos) > 0
for shareinfo in shareinfos:
# have we already validated the hashes on this share?
if shareinfo not in self._valid_shares:
# nope: must check the hashes and extract the actual data
(peerid,data) = shareinfo
try:
# The (seqnum+root_hash+IV) tuple for this share was
# already verified: specifically, all shares in the
# sharemap have a (seqnum+root_hash+IV) pair that was
# present in a validly signed prefix. The remainder
# of the prefix for this particular share has *not*
# been validated, but we don't care since we don't
# use it. self._validate_share() is required to check
# the hashes on the share data (and hash chains) to
# make sure they match root_hash, but is not required
# (and is in fact prohibited, because we don't
# validate the prefix on all shares) from using
# anything else in the share.
validator = self._validate_share_and_extract_data
sharedata = validator(peerid, root_hash, shnum, data)
assert isinstance(sharedata, str)
except CorruptShareError, e:
self.log("share was corrupt: %s" % e, level=log.WEIRD)
sharemap[shnum].discard(shareinfo)
if not sharemap[shnum]:
# remove the key so the test in _check_for_done
# can accurately decide that we don't have enough
# shares to try again right now.
del sharemap[shnum]
# If there are enough remaining shares,
# _check_for_done() will try again
raise
# share is valid: remember it so we won't need to check
# (or extract) it again
self._valid_shares[shareinfo] = sharedata
# the share is now in _valid_shares, so just copy over the
# sharedata
shares[shnum] = self._valid_shares[shareinfo]
# now that the big loop is done, all shares in the sharemap are
# valid, and they're all for the same seqnum+root_hash version, so
# it's now down to doing FEC and decrypt.
elapsed = time.time() - self._started
self._status.timings["fetch"] = elapsed
assert len(shares) >= self._required_shares, len(shares)
d = defer.maybeDeferred(self._decode, shares, segsize, datalength)
d.addCallback(self._decrypt, IV, seqnum, root_hash)
return d
def _validate_share_and_extract_data(self, peerid, root_hash, shnum, data):
# 'data' is the whole SMDF share
self.log("_validate_share_and_extract_data[%d]" % shnum)
assert data[0] == "\x00"
pieces = unpack_share_data(data)
(seqnum, root_hash_copy, IV, k, N, segsize, datalen,
pubkey, signature, share_hash_chain, block_hash_tree,
share_data) = pieces
assert isinstance(share_data, str)
# build the block hash tree. SDMF has only one leaf.
leaves = [hashutil.block_hash(share_data)]
t = hashtree.HashTree(leaves)
if list(t) != block_hash_tree:
raise CorruptShareError(peerid, shnum, "block hash tree failure")
share_hash_leaf = t[0]
t2 = hashtree.IncompleteHashTree(N)
# root_hash was checked by the signature
t2.set_hashes({0: root_hash})
try:
t2.set_hashes(hashes=share_hash_chain,
leaves={shnum: share_hash_leaf})
except (hashtree.BadHashError, hashtree.NotEnoughHashesError), e:
msg = "corrupt hashes: %s" % (e,)
raise CorruptShareError(peerid, shnum, msg)
self.log(" data valid! len=%d" % len(share_data))
return share_data
def _decode(self, shares_dict, segsize, datalength):
# we ought to know these values by now
assert self._required_shares is not None
assert self._total_shares is not None
# shares_dict is a dict mapping shnum to share data, but the codec
# wants two lists.
shareids = []; shares = []
for shareid, share in shares_dict.items():
shareids.append(shareid)
shares.append(share)
assert len(shareids) >= self._required_shares, len(shareids)
# zfec really doesn't want extra shares
shareids = shareids[:self._required_shares]
shares = shares[:self._required_shares]
fec = codec.CRSDecoder()
params = "%d-%d-%d" % (segsize,
self._required_shares, self._total_shares)
fec.set_serialized_params(params)
self.log("params %s, we have %d shares" % (params, len(shares)))
self.log("about to decode, shareids=%s" % (shareids,))
started = time.time()
d = defer.maybeDeferred(fec.decode, shares, shareids)
def _done(buffers):
elapsed = time.time() - started
self._status.timings["decode"] = elapsed
self._status.set_encoding(self._required_shares, self._total_shares)
self.log(" decode done, %d buffers" % len(buffers))
segment = "".join(buffers)
self.log(" joined length %d, datalength %d" %
(len(segment), datalength))
segment = segment[:datalength]
self.log(" segment len=%d" % len(segment))
return segment
def _err(f):
self.log(" decode failed: %s" % f)
return f
d.addCallback(_done)
d.addErrback(_err)
return d
def _decrypt(self, crypttext, IV, seqnum, root_hash):
started = time.time()
key = hashutil.ssk_readkey_data_hash(IV, self._readkey)
decryptor = AES(key)
plaintext = decryptor.process(crypttext)
elapsed = time.time() - started
self._status.timings["decrypt"] = elapsed
# it worked, so record the seqnum and root_hash for next time
self._node._populate_seqnum(seqnum)
self._node._populate_root_hash(root_hash)
return plaintext
def _done(self, contents):
self.log("DONE")
self._running = False
self._status.set_active(False)
self._status.set_status("Done")
self._status.set_progress(1.0)
self._status.set_size(len(contents))
elapsed = time.time() - self._started
self._status.timings["total"] = elapsed
eventually(self._done_deferred.callback, contents)
def get_status(self):
return self._status
class DictOfSets(dict):
def add(self, key, value):
if key in self:
self[key].add(value)
else:
self[key] = set([value])
class PublishStatus:
implements(IPublishStatus)
statusid_counter = count(0)
def __init__(self):
self.timings = {}
self.timings["per_server"] = {}
self.privkey_from = None
self.peers_queried = None
self.sharemap = None # DictOfSets
self.problems = {}
self.active = True
self.storage_index = None
self.helper = False
self.encoding = ("?", "?")
self.initial_read_size = None
self.size = None
self.status = "Not started"
self.progress = 0.0
self.counter = self.statusid_counter.next()
self.started = time.time()
def add_per_server_time(self, peerid, op, elapsed):
assert op in ("read", "write")
if peerid not in self.timings["per_server"]:
self.timings["per_server"][peerid] = []
self.timings["per_server"][peerid].append((op,elapsed))
def get_started(self):
return self.started
def get_storage_index(self):
return self.storage_index
def get_encoding(self):
return self.encoding
def using_helper(self):
return self.helper
def get_size(self):
return self.size
def get_status(self):
return self.status
def get_progress(self):
return self.progress
def get_active(self):
return self.active
def get_counter(self):
return self.counter
def set_storage_index(self, si):
self.storage_index = si
def set_helper(self, helper):
self.helper = helper
def set_encoding(self, k, n):
self.encoding = (k, n)
def set_size(self, size):
self.size = size
def set_status(self, status):
self.status = status
def set_progress(self, value):
self.progress = value
def set_active(self, value):
self.active = value
class Publish:
"""I represent a single act of publishing the mutable file to the grid."""
def __init__(self, filenode):
self._node = filenode
self._storage_index = self._node.get_storage_index()
self._log_prefix = prefix = storage.si_b2a(self._storage_index)[:5]
num = self._node._client.log("Publish(%s): starting" % prefix)
self._log_number = num
self._status = PublishStatus()
self._status.set_storage_index(self._storage_index)
self._status.set_helper(False)
self._status.set_progress(0.0)
self._status.set_active(True)
self._started = time.time()
def log(self, *args, **kwargs):
if 'parent' not in kwargs:
kwargs['parent'] = self._log_number
num = log.msg(*args, **kwargs)
return num
def log_err(self, *args, **kwargs):
if 'parent' not in kwargs:
kwargs['parent'] = self._log_number
num = log.err(*args, **kwargs)
return num
def publish(self, newdata):
"""Publish the filenode's current contents. Returns a Deferred that
fires (with None) when the publish has done as much work as it's ever
going to do, or errbacks with ConsistencyError if it detects a
simultaneous write.
"""
# 1: generate shares (SDMF: files are small, so we can do it in RAM)
# 2: perform peer selection, get candidate servers
# 2a: send queries to n+epsilon servers, to determine current shares
# 2b: based upon responses, create target map
# 3: send slot_testv_and_readv_and_writev messages
# 4: as responses return, update share-dispatch table
# 4a: may need to run recovery algorithm
# 5: when enough responses are back, we're done
self.log("starting publish, datalen is %s" % len(newdata))
self._status.set_size(len(newdata))
self._writekey = self._node.get_writekey()
assert self._writekey, "need write capability to publish"
old_roothash = self._node._current_roothash
old_seqnum = self._node._current_seqnum
assert old_seqnum is not None, "must read before replace"
self._new_seqnum = old_seqnum + 1
# read-before-replace also guarantees these fields are available
readkey = self._node.get_readkey()
required_shares = self._node.get_required_shares()
total_shares = self._node.get_total_shares()
self._pubkey = self._node.get_pubkey()
self._status.set_encoding(required_shares, total_shares)
# these two may not be, we might have to get them from the first peer
self._privkey = self._node.get_privkey()
self._encprivkey = self._node.get_encprivkey()
IV = os.urandom(16)
# we read only 1KB because all we generally care about is the seqnum
# ("prefix") info, so we know which shares are where. We need to get
# the privkey from somebody, which means reading more like 3KB, but
# the code in _obtain_privkey will ensure that we manage that even if
# we need an extra roundtrip. TODO: arrange to read 3KB from one peer
# who is likely to hold a share, so we can avoid the latency of that
# extra roundtrip. 3KB would get us the encprivkey from a dirnode
# with up to 7 entries, allowing us to make an update in 2 RTT
# instead of 3.
self._read_size = 1000
self._status.initial_read_size = self._read_size
d = defer.succeed(total_shares)
d.addCallback(self._query_peers)
d.addCallback(self._query_peers_done)
d.addCallback(self._obtain_privkey)
d.addCallback(self._obtain_privkey_done)
d.addCallback(self._encrypt_and_encode, newdata, readkey, IV,
required_shares, total_shares)
d.addCallback(self._generate_shares, self._new_seqnum, IV)
d.addCallback(self._send_shares, IV)
d.addCallback(self._maybe_recover)
d.addCallback(self._done)
return d
def _query_peers(self, total_shares):
self.log("_query_peers")
self._query_peers_started = now = time.time()
elapsed = now - self._started
self._status.timings["setup"] = elapsed
storage_index = self._storage_index
# In 0.7.0, we went through extra work to make sure that we include
# ourselves in the peerlist, mainly to match Retrieve (which did the
# same thing. With the post-0.7.0 Introducer refactoring, we got rid
# of the include-myself flags, and standardized on the
# uploading/downloading node not being special.
# One nice feature of the old approach was that by putting a share on
# the local storage server, we're more likely to be able to retrieve
# a copy of the encrypted private key (even if all the old servers
# have gone away), so we can regenerate new shares even if we can't
# retrieve the old contents. This need will eventually go away when
# we switch to DSA-based mutable files (which store the private key
# in the URI).
peerlist = self._node._client.get_permuted_peers("storage",
storage_index)
current_share_peers = DictOfSets()
reachable_peers = {}
# list of (peerid, shnum, offset, length) where the encprivkey might
# be found
self._encprivkey_shares = []
EPSILON = total_shares / 2
#partial_peerlist = islice(peerlist, total_shares + EPSILON)
partial_peerlist = peerlist[:total_shares+EPSILON]
self._status.peers_queried = len(partial_peerlist)
self._storage_servers = {}
started = time.time()
dl = []
for permutedid, (peerid, ss) in enumerate(partial_peerlist):
self._storage_servers[peerid] = ss
d = self._do_query(ss, peerid, storage_index)
d.addCallback(self._got_query_results,
peerid, permutedid,
reachable_peers, current_share_peers, started)
dl.append(d)
d = defer.DeferredList(dl)
d.addCallback(self._got_all_query_results,
total_shares, reachable_peers,
current_share_peers)
# TODO: add an errback to, probably to ignore that peer
# TODO: if we can't get a privkey from these servers, consider
# looking farther afield. Be aware of the old 0.7.0 behavior that
# causes us to create our initial directory before we've connected to
# anyone but ourselves.. those old directories may not be
# retrieveable if our own server is no longer in the early part of
# the permuted peerlist.
return d
def _do_read(self, ss, peerid, storage_index, shnums, readv):
# isolate the callRemote to a separate method, so tests can subclass
# Publish and override it
d = ss.callRemote("slot_readv", storage_index, shnums, readv)
return d
def _do_query(self, ss, peerid, storage_index):
self.log("querying %s" % idlib.shortnodeid_b2a(peerid))
d = self._do_read(ss, peerid, storage_index, [], [(0, self._read_size)])
return d
def _got_query_results(self, datavs, peerid, permutedid,
reachable_peers, current_share_peers, started):
lp = self.log(format="_got_query_results from %(peerid)s",
peerid=idlib.shortnodeid_b2a(peerid))
elapsed = time.time() - started
self._status.add_per_server_time(peerid, "read", elapsed)
assert isinstance(datavs, dict)
reachable_peers[peerid] = permutedid
if not datavs:
self.log("peer has no shares", parent=lp)
for shnum, datav in datavs.items():
lp2 = self.log("peer has shnum %d" % shnum, parent=lp)
assert len(datav) == 1
data = datav[0]
# We want (seqnum, root_hash, IV) from all servers to know what
# versions we are replacing. We want the encprivkey from one
# server (assuming it's valid) so we know our own private key, so
# we can sign our update. SMDF: read the whole share from each
# server. TODO: later we can optimize this to transfer less data.
# we assume that we have enough data to extract the signature.
# TODO: if this raises NeedMoreDataError, arrange to do another
# read pass.
r = unpack_prefix_and_signature(data)
(seqnum, root_hash, IV, k, N, segsize, datalen,
pubkey_s, signature, prefix) = r
# self._pubkey is present because we require read-before-replace
valid = self._pubkey.verify(prefix, signature)
if not valid:
self.log(format="bad signature from %(peerid)s shnum %(shnum)d",
peerid=idlib.shortnodeid_b2a(peerid), shnum=shnum,
parent=lp2, level=log.WEIRD)
continue
self.log(format="peer has goodsig shnum %(shnum)d seqnum %(seqnum)d",
shnum=shnum, seqnum=seqnum,
parent=lp2, level=log.NOISY)
share = (shnum, seqnum, root_hash)
current_share_peers.add(shnum, (peerid, seqnum, root_hash) )
if not self._privkey:
self._try_to_extract_privkey(data, peerid, shnum)
def _try_to_extract_privkey(self, data, peerid, shnum):
try:
r = unpack_share(data)
except NeedMoreDataError, e:
# this share won't help us. oh well.
offset = e.encprivkey_offset
length = e.encprivkey_length
self.log("shnum %d on peerid %s: share was too short (%dB) "
"to get the encprivkey; [%d:%d] ought to hold it" %
(shnum, idlib.shortnodeid_b2a(peerid), len(data),
offset, offset+length))
# NOTE: if uncoordinated writes are taking place, someone might
# change the share (and most probably move the encprivkey) before
# we get a chance to do one of these reads and fetch it. This
# will cause us to see a NotEnoughPeersError(unable to fetch
# privkey) instead of an UncoordinatedWriteError . This is a
# nuisance, but it will go away when we move to DSA-based mutable
# files (since the privkey will be small enough to fit in the
# write cap).
self._encprivkey_shares.append( (peerid, shnum, offset, length))
return
(seqnum, root_hash, IV, k, N, segsize, datalen,
pubkey, signature, share_hash_chain, block_hash_tree,
share_data, enc_privkey) = r
return self._try_to_validate_privkey(enc_privkey, peerid, shnum)
def _try_to_validate_privkey(self, enc_privkey, peerid, shnum):
alleged_privkey_s = self._node._decrypt_privkey(enc_privkey)
alleged_writekey = hashutil.ssk_writekey_hash(alleged_privkey_s)
if alleged_writekey != self._writekey:
self.log("invalid privkey from %s shnum %d" %
(idlib.nodeid_b2a(peerid)[:8], shnum), level=log.WEIRD)
return
# it's good
self.log("got valid privkey from shnum %d on peerid %s" %
(shnum, idlib.shortnodeid_b2a(peerid)))
self._privkey = rsa.create_signing_key_from_string(alleged_privkey_s)
self._encprivkey = enc_privkey
self._node._populate_encprivkey(self._encprivkey)
self._node._populate_privkey(self._privkey)
def _got_all_query_results(self, res,
total_shares, reachable_peers,
current_share_peers):
self.log("_got_all_query_results")
# now that we know everything about the shares currently out there,
# decide where to place the new shares.
# if an old share X is on a node, put the new share X there too.
# TODO: 1: redistribute shares to achieve one-per-peer, by copying
# shares from existing peers to new (less-crowded) ones. The
# old shares must still be updated.
# TODO: 2: move those shares instead of copying them, to reduce future
# update work
# if log.recording_noisy
logmsg = []
for shnum in range(total_shares):
logmsg2 = []
for oldplace in current_share_peers.get(shnum, []):
(peerid, seqnum, R) = oldplace
logmsg2.append("%s:#%d:R=%s" % (idlib.shortnodeid_b2a(peerid),
seqnum, base32.b2a(R)[:4]))
logmsg.append("sh%d on (%s)" % (shnum, "/".join(logmsg2)))
self.log("sharemap: %s" % (", ".join(logmsg)), level=log.NOISY)
self.log("we are planning to push new seqnum=#%d" % self._new_seqnum,
level=log.NOISY)
shares_needing_homes = range(total_shares)
target_map = DictOfSets() # maps shnum to set((peerid,oldseqnum,oldR))
shares_per_peer = DictOfSets()
for shnum in range(total_shares):
for oldplace in current_share_peers.get(shnum, []):
(peerid, seqnum, R) = oldplace
if seqnum >= self._new_seqnum:
self.log("somebody has a newer sequence number than what we were uploading",
level=log.WEIRD)
self.log(format="peerid=%(peerid)s, theirs=%(seqnum)d, mine=%(new_seqnum)d",
peerid=idlib.shortnodeid_b2a(peerid),
seqnum=seqnum,
new_seqnum=self._new_seqnum)
raise UncoordinatedWriteError("somebody has a newer sequence number than us")
target_map.add(shnum, oldplace)
shares_per_peer.add(peerid, shnum)
if shnum in shares_needing_homes:
shares_needing_homes.remove(shnum)
# now choose homes for the remaining shares. We prefer peers with the
# fewest target shares, then peers with the lowest permuted index. If
# there are no shares already in place, this will assign them
# one-per-peer in the normal permuted order.
while shares_needing_homes:
if not reachable_peers:
prefix = storage.si_b2a(self._node.get_storage_index())[:5]
raise NotEnoughPeersError("ran out of peers during upload of (%s); shares_needing_homes: %s, reachable_peers: %s" % (prefix, shares_needing_homes, reachable_peers,))
shnum = shares_needing_homes.pop(0)
possible_homes = reachable_peers.keys()
possible_homes.sort(lambda a,b:
cmp( (len(shares_per_peer.get(a, [])),
reachable_peers[a]),
(len(shares_per_peer.get(b, [])),
reachable_peers[b]) ))
target_peerid = possible_homes[0]
target_map.add(shnum, (target_peerid, None, None) )
shares_per_peer.add(target_peerid, shnum)
assert not shares_needing_homes
target_info = (target_map, shares_per_peer)
return target_info
def _query_peers_done(self, target_info):
self._obtain_privkey_started = now = time.time()
elapsed = time.time() - self._query_peers_started
self._status.timings["query"] = elapsed
return target_info
def _obtain_privkey(self, target_info):
# make sure we've got a copy of our private key.
if self._privkey:
# Must have picked it up during _query_peers. We're good to go.
if "privkey_fetch" not in self._status.timings:
self._status.timings["privkey_fetch"] = 0.0
return target_info
# Nope, we haven't managed to grab a copy, and we still need it. Ask
# peers one at a time until we get a copy. Only bother asking peers
# who've admitted to holding a share.
self._privkey_fetch_started = time.time()
target_map, shares_per_peer = target_info
# pull shares from self._encprivkey_shares
if not self._encprivkey_shares:
raise NotEnoughPeersError("Unable to find a copy of the privkey")
(peerid, shnum, offset, length) = self._encprivkey_shares.pop(0)
ss = self._storage_servers[peerid]
self.log("trying to obtain privkey from %s shnum %d" %
(idlib.shortnodeid_b2a(peerid), shnum))
d = self._do_privkey_query(ss, peerid, shnum, offset, length)
d.addErrback(self.log_err)
d.addCallback(lambda res: self._obtain_privkey(target_info))
return d
def _do_privkey_query(self, rref, peerid, shnum, offset, length):
started = time.time()
d = self._do_read(rref, peerid, self._storage_index,
[shnum], [(offset, length)])
d.addCallback(self._privkey_query_response, peerid, shnum, started)
return d
def _privkey_query_response(self, datav, peerid, shnum, started):
elapsed = time.time() - started
self._status.add_per_server_time(peerid, "read", elapsed)
data = datav[shnum][0]
self._try_to_validate_privkey(data, peerid, shnum)
elapsed = time.time() - self._privkey_fetch_started
self._status.timings["privkey_fetch"] = elapsed
self._status.privkey_from = peerid
def _obtain_privkey_done(self, target_info):
elapsed = time.time() - self._obtain_privkey_started
self._status.timings["privkey"] = elapsed
return target_info
def _encrypt_and_encode(self, target_info,
newdata, readkey, IV,
required_shares, total_shares):
self.log("_encrypt_and_encode")
started = time.time()
key = hashutil.ssk_readkey_data_hash(IV, readkey)
enc = AES(key)
crypttext = enc.process(newdata)
assert len(crypttext) == len(newdata)
now = time.time()
self._status.timings["encrypt"] = now - started
started = now
# now apply FEC
self.MAX_SEGMENT_SIZE = 1024*1024
data_length = len(crypttext)
segment_size = min(self.MAX_SEGMENT_SIZE, len(crypttext))
# this must be a multiple of self.required_shares
segment_size = mathutil.next_multiple(segment_size, required_shares)
if segment_size:
self.num_segments = mathutil.div_ceil(len(crypttext), segment_size)
else:
self.num_segments = 0
assert self.num_segments in [0, 1,] # SDMF restrictions
fec = codec.CRSEncoder()
fec.set_params(segment_size, required_shares, total_shares)
piece_size = fec.get_block_size()
crypttext_pieces = [None] * required_shares
for i in range(len(crypttext_pieces)):
offset = i * piece_size
piece = crypttext[offset:offset+piece_size]
piece = piece + "\x00"*(piece_size - len(piece)) # padding
crypttext_pieces[i] = piece
assert len(piece) == piece_size
d = fec.encode(crypttext_pieces)
def _done_encoding(res):
elapsed = time.time() - started
self._status.timings["encode"] = elapsed
return res
d.addCallback(_done_encoding)
d.addCallback(lambda shares_and_shareids:
(shares_and_shareids,
required_shares, total_shares,
segment_size, data_length,
target_info) )
return d
def _generate_shares(self, (shares_and_shareids,
required_shares, total_shares,
segment_size, data_length,
target_info),
seqnum, IV):
self.log("_generate_shares")
started = time.time()
# we should know these by now
privkey = self._privkey
encprivkey = self._encprivkey
pubkey = self._pubkey
(shares, share_ids) = shares_and_shareids
assert len(shares) == len(share_ids)
assert len(shares) == total_shares
all_shares = {}
block_hash_trees = {}
share_hash_leaves = [None] * len(shares)
for i in range(len(shares)):
share_data = shares[i]
shnum = share_ids[i]
all_shares[shnum] = share_data
# build the block hash tree. SDMF has only one leaf.
leaves = [hashutil.block_hash(share_data)]
t = hashtree.HashTree(leaves)
block_hash_trees[shnum] = block_hash_tree = list(t)
share_hash_leaves[shnum] = t[0]
for leaf in share_hash_leaves:
assert leaf is not None
share_hash_tree = hashtree.HashTree(share_hash_leaves)
share_hash_chain = {}
for shnum in range(total_shares):
needed_hashes = share_hash_tree.needed_hashes(shnum)
share_hash_chain[shnum] = dict( [ (i, share_hash_tree[i])
for i in needed_hashes ] )
root_hash = share_hash_tree[0]
assert len(root_hash) == 32
self.log("my new root_hash is %s" % base32.b2a(root_hash))
prefix = pack_prefix(seqnum, root_hash, IV,
required_shares, total_shares,
segment_size, data_length)
# now pack the beginning of the share. All shares are the same up
# to the signature, then they have divergent share hash chains,
# then completely different block hash trees + IV + share data,
# then they all share the same encprivkey at the end. The sizes
# of everything are the same for all shares.
sign_started = time.time()
signature = privkey.sign(prefix)
self._status.timings["sign"] = time.time() - sign_started
verification_key = pubkey.serialize()
final_shares = {}
for shnum in range(total_shares):
final_share = pack_share(prefix,
verification_key,
signature,
share_hash_chain[shnum],
block_hash_trees[shnum],
all_shares[shnum],
encprivkey)
final_shares[shnum] = final_share
elapsed = time.time() - started
self._status.timings["pack"] = elapsed
return (seqnum, root_hash, final_shares, target_info)
def _send_shares(self, (seqnum, root_hash, final_shares, target_info), IV):
self.log("_send_shares")
started = time.time()
# we're finally ready to send out our shares. If we encounter any
# surprises here, it's because somebody else is writing at the same
# time. (Note: in the future, when we remove the _query_peers() step
# and instead speculate about [or remember] which shares are where,
# surprises here are *not* indications of UncoordinatedWriteError,
# and we'll need to respond to them more gracefully.)
target_map, shares_per_peer = target_info
my_checkstring = pack_checkstring(seqnum, root_hash, IV)
peer_messages = {}
expected_old_shares = {}
for shnum, peers in target_map.items():
for (peerid, old_seqnum, old_root_hash) in peers:
testv = [(0, len(my_checkstring), "le", my_checkstring)]
new_share = final_shares[shnum]
writev = [(0, new_share)]
if peerid not in peer_messages:
peer_messages[peerid] = {}
peer_messages[peerid][shnum] = (testv, writev, None)
if peerid not in expected_old_shares:
expected_old_shares[peerid] = {}
expected_old_shares[peerid][shnum] = (old_seqnum, old_root_hash)
read_vector = [(0, len(my_checkstring))]
dl = []
# ok, send the messages!
self._surprised = False
dispatch_map = DictOfSets()
for peerid, tw_vectors in peer_messages.items():
write_enabler = self._node.get_write_enabler(peerid)
renew_secret = self._node.get_renewal_secret(peerid)
cancel_secret = self._node.get_cancel_secret(peerid)
secrets = (write_enabler, renew_secret, cancel_secret)
d = self._do_testreadwrite(peerid, secrets,
tw_vectors, read_vector)
d.addCallback(self._got_write_answer, tw_vectors, my_checkstring,
peerid, expected_old_shares[peerid], dispatch_map,
started)
dl.append(d)
d = defer.DeferredList(dl)
def _done_sending(res):
elapsed = time.time() - started
self._status.timings["push"] = elapsed
self._status.sharemap = dispatch_map
return res
d.addCallback(_done_sending)
d.addCallback(lambda res: (self._surprised, dispatch_map))
return d
def _do_testreadwrite(self, peerid, secrets,
tw_vectors, read_vector):
storage_index = self._node._uri.storage_index
ss = self._storage_servers[peerid]
d = ss.callRemote("slot_testv_and_readv_and_writev",
storage_index,
secrets,
tw_vectors,
read_vector)
return d
def _got_write_answer(self, answer, tw_vectors, my_checkstring,
peerid, expected_old_shares,
dispatch_map, started):
lp = self.log("_got_write_answer from %s" %
idlib.shortnodeid_b2a(peerid))
elapsed = time.time() - started
self._status.add_per_server_time(peerid, "write", elapsed)
wrote, read_data = answer
surprised = False
(new_seqnum,new_root_hash,new_IV) = unpack_checkstring(my_checkstring)
if wrote:
for shnum in tw_vectors:
dispatch_map.add(shnum, (peerid, new_seqnum, new_root_hash))
else:
# surprise! our testv failed, so the write did not happen
self.log("our testv failed, that write did not happen",
parent=lp, level=log.WEIRD)
surprised = True
for shnum, (old_cs,) in read_data.items():
(old_seqnum, old_root_hash, IV) = unpack_checkstring(old_cs)
if not wrote:
dispatch_map.add(shnum, (peerid, old_seqnum, old_root_hash))
if shnum not in expected_old_shares:
# surprise! there was a share we didn't know about
self.log("they had share %d that we didn't know about" % shnum,
parent=lp, level=log.WEIRD)
surprised = True
else:
seqnum, root_hash = expected_old_shares[shnum]
if seqnum is not None:
if seqnum != old_seqnum or root_hash != old_root_hash:
# surprise! somebody modified the share on us
self.log("somebody modified the share on us:"
" shnum=%d: I thought they had #%d:R=%s,"
" but testv reported #%d:R=%s" %
(shnum,
seqnum, base32.b2a(root_hash)[:4],
old_seqnum, base32.b2a(old_root_hash)[:4]),
parent=lp, level=log.WEIRD)
surprised = True
if surprised:
self._surprised = True
def _log_dispatch_map(self, dispatch_map):
for shnum, places in dispatch_map.items():
sent_to = [(idlib.shortnodeid_b2a(peerid),
seqnum,
base32.b2a(root_hash)[:4])
for (peerid,seqnum,root_hash) in places]
self.log(" share %d sent to: %s" % (shnum, sent_to),
level=log.NOISY)
def _maybe_recover(self, (surprised, dispatch_map)):
self.log("_maybe_recover, surprised=%s, dispatch_map:" % surprised,
level=log.NOISY)
self._log_dispatch_map(dispatch_map)
if not surprised:
self.log(" no recovery needed")
return
self.log("We need recovery!", level=log.WEIRD)
print "RECOVERY NOT YET IMPLEMENTED"
# but dispatch_map will help us do it
raise UncoordinatedWriteError("I was surprised!")
def _done(self, res):
now = time.time()
self._status.timings["total"] = now - self._started
self._status.set_active(False)
self._status.set_status("Done")
self._status.set_progress(1.0)
return None
def get_status(self):
return self._status
# use client.create_mutable_file() to make one of these
class MutableFileNode:
implements(IMutableFileNode)
publish_class = Publish
retrieve_class = Retrieve
SIGNATURE_KEY_SIZE = 2048
def __init__(self, client):
self._client = client
self._pubkey = None # filled in upon first read
self._privkey = None # filled in if we're mutable
self._required_shares = None # ditto
self._total_shares = None # ditto
self._sharemap = {} # known shares, shnum-to-[nodeids]
self._current_data = None # SDMF: we're allowed to cache the contents
self._current_roothash = None # ditto
self._current_seqnum = None # ditto
def __repr__(self):
return "<%s %x %s %s>" % (self.__class__.__name__, id(self), self.is_readonly() and 'RO' or 'RW', hasattr(self, '_uri') and self._uri.abbrev())
def init_from_uri(self, myuri):
# we have the URI, but we have not yet retrieved the public
# verification key, nor things like 'k' or 'N'. If and when someone
# wants to get our contents, we'll pull from shares and fill those
# in.
self._uri = IMutableFileURI(myuri)
if not self._uri.is_readonly():
self._writekey = self._uri.writekey
self._readkey = self._uri.readkey
self._storage_index = self._uri.storage_index
self._fingerprint = self._uri.fingerprint
# the following values are learned during Retrieval
# self._pubkey
# self._required_shares
# self._total_shares
# and these are needed for Publish. They are filled in by Retrieval
# if possible, otherwise by the first peer that Publish talks to.
self._privkey = None
self._encprivkey = None
return self
def create(self, initial_contents):
"""Call this when the filenode is first created. This will generate
the keys, generate the initial shares, wait until at least numpeers
are connected, allocate shares, and upload the initial
contents. Returns a Deferred that fires (with the MutableFileNode
instance you should use) when it completes.
"""
self._required_shares = 3
self._total_shares = 10
d = defer.maybeDeferred(self._generate_pubprivkeys)
def _generated( (pubkey, privkey) ):
self._pubkey, self._privkey = pubkey, privkey
pubkey_s = self._pubkey.serialize()
privkey_s = self._privkey.serialize()
self._writekey = hashutil.ssk_writekey_hash(privkey_s)
self._encprivkey = self._encrypt_privkey(self._writekey, privkey_s)
self._fingerprint = hashutil.ssk_pubkey_fingerprint_hash(pubkey_s)
self._uri = WriteableSSKFileURI(self._writekey, self._fingerprint)
self._readkey = self._uri.readkey
self._storage_index = self._uri.storage_index
# TODO: seqnum/roothash: really we mean "doesn't matter since
# nobody knows about us yet"
self._current_seqnum = 0
self._current_roothash = "\x00"*32
return self._publish(initial_contents)
d.addCallback(_generated)
return d
def _generate_pubprivkeys(self):
# RSA key generation for a 2048 bit key takes between 0.8 and 3.2 secs
signer = rsa.generate(self.SIGNATURE_KEY_SIZE)
verifier = signer.get_verifying_key()
return verifier, signer
def _publish(self, initial_contents):
p = self.publish_class(self)
self._client.notify_publish(p)
d = p.publish(initial_contents)
d.addCallback(lambda res: self)
return d
def _encrypt_privkey(self, writekey, privkey):
enc = AES(writekey)
crypttext = enc.process(privkey)
return crypttext
def _decrypt_privkey(self, enc_privkey):
enc = AES(self._writekey)
privkey = enc.process(enc_privkey)
return privkey
def _populate(self, stuff):
# the Retrieval object calls this with values it discovers when
# downloading the slot. This is how a MutableFileNode that was
# created from a URI learns about its full key.
pass
def _populate_pubkey(self, pubkey):
self._pubkey = pubkey
def _populate_required_shares(self, required_shares):
self._required_shares = required_shares
def _populate_total_shares(self, total_shares):
self._total_shares = total_shares
def _populate_seqnum(self, seqnum):
self._current_seqnum = seqnum
def _populate_root_hash(self, root_hash):
self._current_roothash = root_hash
def _populate_privkey(self, privkey):
self._privkey = privkey
def _populate_encprivkey(self, encprivkey):
self._encprivkey = encprivkey
def get_write_enabler(self, peerid):
assert len(peerid) == 20
return hashutil.ssk_write_enabler_hash(self._writekey, peerid)
def get_renewal_secret(self, peerid):
assert len(peerid) == 20
crs = self._client.get_renewal_secret()
frs = hashutil.file_renewal_secret_hash(crs, self._storage_index)
return hashutil.bucket_renewal_secret_hash(frs, peerid)
def get_cancel_secret(self, peerid):
assert len(peerid) == 20
ccs = self._client.get_cancel_secret()
fcs = hashutil.file_cancel_secret_hash(ccs, self._storage_index)
return hashutil.bucket_cancel_secret_hash(fcs, peerid)
def get_writekey(self):
return self._writekey
def get_readkey(self):
return self._readkey
def get_storage_index(self):
return self._storage_index
def get_privkey(self):
return self._privkey
def get_encprivkey(self):
return self._encprivkey
def get_pubkey(self):
return self._pubkey
def get_required_shares(self):
return self._required_shares
def get_total_shares(self):
return self._total_shares
def get_uri(self):
return self._uri.to_string()
def get_size(self):
return "?" # TODO: this is likely to cause problems, not being an int
def get_readonly(self):
if self.is_readonly():
return self
ro = MutableFileNode(self._client)
ro.init_from_uri(self._uri.get_readonly())
return ro
def get_readonly_uri(self):
return self._uri.get_readonly().to_string()
def is_mutable(self):
return self._uri.is_mutable()
def is_readonly(self):
return self._uri.is_readonly()
def __hash__(self):
return hash((self.__class__, self._uri))
def __cmp__(self, them):
if cmp(type(self), type(them)):
return cmp(type(self), type(them))
if cmp(self.__class__, them.__class__):
return cmp(self.__class__, them.__class__)
return cmp(self._uri, them._uri)
def get_verifier(self):
return IMutableFileURI(self._uri).get_verifier()
def check(self):
verifier = self.get_verifier()
return self._client.getServiceNamed("checker").check(verifier)
def download(self, target):
# fake it. TODO: make this cleaner.
d = self.download_to_data()
def _done(data):
target.open(len(data))
target.write(data)
target.close()
return target.finish()
d.addCallback(_done)
return d
def download_to_data(self):
r = self.retrieve_class(self)
self._client.notify_retrieve(r)
return r.retrieve()
def replace(self, newdata):
r = self.retrieve_class(self)
self._client.notify_retrieve(r)
d = r.retrieve()
d.addCallback(lambda res: self._publish(newdata))
return d
class MutableWatcher(service.MultiService):
MAX_PUBLISH_STATUSES = 20
MAX_RETRIEVE_STATUSES = 20
name = "mutable-watcher"
def __init__(self):
service.MultiService.__init__(self)
self._all_publish = weakref.WeakKeyDictionary()
self._recent_publish_status = []
self._all_retrieve = weakref.WeakKeyDictionary()
self._recent_retrieve_status = []
def notify_publish(self, p):
self._all_publish[p] = None
self._recent_publish_status.append(p.get_status())
while len(self._recent_publish_status) > self.MAX_PUBLISH_STATUSES:
self._recent_publish_status.pop(0)
def list_all_publish(self):
return self._all_publish.keys()
def list_active_publish(self):
return [p.get_status() for p in self._all_publish.keys()
if p.get_status().get_active()]
def list_recent_publish(self):
return self._recent_publish_status
def notify_retrieve(self, r):
self._all_retrieve[r] = None
self._recent_retrieve_status.append(r.get_status())
while len(self._recent_retrieve_status) > self.MAX_RETRIEVE_STATUSES:
self._recent_retrieve_status.pop(0)
def list_all_retrieve(self):
return self._all_retrieve.keys()
def list_active_retrieve(self):
return [p.get_status() for p in self._all_retrieve.keys()
if p.get_status().get_active()]
def list_recent_retrieve(self):
return self._recent_retrieve_status