def _digest_check_func(self, payload, digest):
digest_clone = sha1_stream_clone(self._backward_digest)
sha1_stream_update(digest_clone, payload)
new_digest = sha1_stream_finalize(digest_clone)[:4]
if new_digest != digest:
logger.debug(
'received cell digest not equal ({!r} != {!r}); payload = {!r}'
.format(to_hex(new_digest), to_hex(digest), to_hex(payload)))
return False
sha1_stream_update(self._backward_digest, payload)
return True
def parse_header(payload):
try:
header = struct.unpack('!BHH4sH498s', payload)
fields = ['cell_num', 'is_recognized', 'stream_id', 'digest', 'relay_payload_len', 'relay_payload_raw']
return dict(zip(fields, header))
except struct.error:
logger.error("Can't unpack: %r", to_hex(payload))
raise
def set_decrypted(self, cell_num, stream_id, digest, relay_payload_len, relay_payload_raw, **kwargs):
relay_payload = relay_payload_raw[:relay_payload_len]
padding = relay_payload_raw[relay_payload_len:]
if all([b == 0 for b in padding]):
padding = b''
try:
cell_type = TorCommands.get_relay_by_num(cell_num)
logger.debug('Deserialize %s relay cell', cell_type.__name__)
inner_cell = TorCell.deserialize(cell_type, 0, relay_payload, 0)
except BaseException:
logger.error("Can't deserialize %i cell: %r", cell_num, to_hex(relay_payload))
raise
self._set_inits(inner_cell, padding, stream_id, digest)
self._encrypted = None
self._checked = True
