def _reconstruct_block(blockinfolist):
# private helper to reconstruct a block
# xor the blocks together
currentresult = blockinfolist[0]['xorblock']
for xorblockdict in blockinfolist[1:]:
currentresult = simplexordatastore.do_xor(currentresult, xorblockdict['xorblock'])
# and return the answer
return currentresult
def _reconstruct_block(blockinfolist):
# private helper to reconstruct a block
# xor the blocks together
currentresult = blockinfolist[0]['xorblock']
for xorblockdict in blockinfolist[1:]:
currentresult = simplexordatastore.do_xor(currentresult, xorblockdict['xorblock'])
# and return the answer
return currentresult
def __init__(self, mirrorinfolist, blocklist, manifestdict, privacythreshold, pollinginterval = .1):
"""
<Purpose>
Get ready to handle requests for XOR block strings, etc.
<Arguments>
mirrorinfolist: a list of dictionaries with information about mirrors
blocklist: the blocks that need to be retrieved
manifestdict: the manifest with information about the release
privacythreshold: the number of mirrors that would need to collude to
break privacy
pollinginterval: the amount of time to sleep between checking for
the ability to serve a mirror.
<Exceptions>
TypeError may be raised if invalid parameters are given.
InsufficientMirrors if there are not enough mirrors
"""
self.blocklist = blocklist
self.manifestdict = manifestdict
self.privacythreshold = privacythreshold
self.pollinginterval = pollinginterval
print "-----mirrorinfolist---------------/n prasit"
print mirrorinfolist
print "-----blocklist---------------/nprasit"
print blocklist
print "-----manifestdict---------------/nprasit"
print manifestdict
if len(mirrorinfolist) < self.privacythreshold:
raise InsufficientMirrors("Requested the use of "+str(self.privacythreshold)+" mirrors, but only "+str(len(mirrorinfolist))+" were available.")
# now we do the 'random' part. I copy the mirrorinfolist to avoid changing
# the list in place.
self.fullmirrorinfolist = mirrorinfolist[:]
random.shuffle(self.fullmirrorinfolist)
# let's make a list of mirror information (what has been retrieved, etc.)
self.activemirrorinfolist = []
for mirrorinfo in self.fullmirrorinfolist[:self.privacythreshold]:
thisrequestinfo = {}
thisrequestinfo['mirrorinfo'] = mirrorinfo
thisrequestinfo['servingrequest'] = False
thisrequestinfo['blocksneeded'] = blocklist[:]
thisrequestinfo['blockbitstringlist'] = []
self.activemirrorinfolist.append(thisrequestinfo)
#print manifestdict['blockcount'] #prasit
bitstringlength = uppirlib.compute_bitstring_length(manifestdict['blockcount'])
# let's generate the bitstrings
for thisrequestinfo in self.activemirrorinfolist[:-1]:
for block in blocklist:
# I'll generate random bitstrings for N-1 of the mirrors...
thisrequestinfo['blockbitstringlist'].append(_randomnumberfunction(bitstringlength))
# now, let's do the 'derived' ones...
for blocknum in range(len(blocklist)):
thisbitstring = '\0'*bitstringlength
# xor the random strings together
for requestinfo in self.activemirrorinfolist[:-1]:
thisbitstring = simplexordatastore.do_xor(thisbitstring, requestinfo['blockbitstringlist'][blocknum])
# ...and flip the appropriate bit for the block we want
#print thisbitstring #prasit
thisbitstring = uppirlib.flip_bitstring_bit(thisbitstring, blocklist[blocknum])
#print thisbitstring #prasit
self.activemirrorinfolist[-1]['blockbitstringlist'].append(thisbitstring)
# we're done setting up the bitstrings!
# want to have a structure for locking
self.tablelock = threading.Lock()
# and we'll keep track of the ones that are waiting in the wings...
self.backupmirrorinfolist = self.fullmirrorinfolist[self.privacythreshold:]
# the returned blocks are put here...
self.returnedxorblocksdict = {}
for blocknum in blocklist:
# make these all empty lists to start with
self.returnedxorblocksdict[blocknum] = []
# and here is where they are put when reconstructed
self.finishedblockdict = {}
def __init__(self, mirrorinfolist, blocklist, manifestdict, privacythreshold, pollinginterval = .1):
"""
<Purpose>
Get ready to handle requests for XOR block strings, etc.
<Arguments>
mirrorinfolist: a list of dictionaries with information about mirrors
blocklist: the blocks that need to be retrieved
manifestdict: the manifest with information about the release
privacythreshold: the number of mirrors that would need to collude to
break privacy
pollinginterval: the amount of time to sleep between checking for
the ability to serve a mirror.
<Exceptions>
TypeError may be raised if invalid parameters are given.
InsufficientMirrors if there are not enough mirrors
"""
self.blocklist = blocklist
self.manifestdict = manifestdict
self.privacythreshold = privacythreshold
self.pollinginterval = pollinginterval
if len(mirrorinfolist) < self.privacythreshold:
raise InsufficientMirrors("Requested the use of "+str(self.privacythreshold)+" mirrors, but only "+str(len(mirrorinfolist))+" were available.")
# now we do the 'random' part. I copy the mirrorinfolist to avoid changing
# the list in place.
self.fullmirrorinfolist = mirrorinfolist[:]
random.shuffle(self.fullmirrorinfolist)
# let's make a list of mirror information (what has been retrieved, etc.)
self.activemirrorinfolist = []
for mirrorinfo in self.fullmirrorinfolist[:self.privacythreshold]:
thisrequestinfo = {}
thisrequestinfo['mirrorinfo'] = mirrorinfo
thisrequestinfo['servingrequest'] = False
thisrequestinfo['blocksneeded'] = blocklist[:]
thisrequestinfo['blockbitstringlist'] = []
self.activemirrorinfolist.append(thisrequestinfo)
bitstringlength = uppirlib.compute_bitstring_length(manifestdict['blockcount'])
# let's generate the bitstrings
for thisrequestinfo in self.activemirrorinfolist[:-1]:
for block in blocklist:
# I'll generate random bitstrings for N-1 of the mirrors...
thisrequestinfo['blockbitstringlist'].append(_randomnumberfunction(bitstringlength))
# now, let's do the 'derived' ones...
for blocknum in range(len(blocklist)):
thisbitstring = '\0'*bitstringlength
# xor the random strings together
for requestinfo in self.activemirrorinfolist[:-1]:
thisbitstring = simplexordatastore.do_xor(thisbitstring, requestinfo['blockbitstringlist'][blocknum])
# ...and flip the appropriate bit for the block we want
thisbitstring = uppirlib.flip_bitstring_bit(thisbitstring, blocklist[blocknum])
self.activemirrorinfolist[-1]['blockbitstringlist'].append(thisbitstring)
# we're done setting up the bitstrings!
# want to have a structure for locking
self.tablelock = threading.Lock()
# and we'll keep track of the ones that are waiting in the wings...
self.backupmirrorinfolist = self.fullmirrorinfolist[self.privacythreshold:]
# the returned blocks are put here...
self.returnedxorblocksdict = {}
for blocknum in blocklist:
# make these all empty lists to start with
self.returnedxorblocksdict[blocknum] = []
# and here is where they are put when reconstructed
self.finishedblockdict = {}
