def _modexp(data):
base_length, exponent_length, modulus_length = _extract_lengths(data)
if base_length == 0:
return 0
elif modulus_length == 0:
return 0
# compute start:end indexes
base_end_idx = 96 + base_length
exponent_end_idx = base_end_idx + exponent_length
modulus_end_dx = exponent_end_idx + modulus_length
# extract arguments
modulus_bytes = zpad_right(
data[exponent_end_idx:modulus_end_dx],
to_size=modulus_length,
)
modulus = big_endian_to_int(modulus_bytes)
if modulus == 0:
return 0
base_bytes = zpad_right(data[96:base_end_idx], to_size=base_length)
base = big_endian_to_int(base_bytes)
exponent_bytes = zpad_right(
data[base_end_idx:exponent_end_idx],
to_size=exponent_length,
)
exponent = big_endian_to_int(exponent_bytes)
print('base', base, 'exponent', exponent, 'modulus', modulus)
result = pow(base, exponent, modulus)
return result
def random_collation(shard_id, period):
body = zpad_right(int_to_big_endian(random.getrandbits(8 * 32)), COLLATION_SIZE)
header = CollationHeader(
shard_id=shard_id,
period=period,
chunk_root=calc_chunk_root(body),
proposer_address=b"\xff" * 20,
)
return Collation(header, body)
def generate_collations():
explicit_params = {}
for period in itertools.count():
default_params = {
"shard_id": 0,
"period": period,
"body": zpad_right(b"body%d" % period, COLLATION_SIZE),
"proposer_address": zpad_right(b"proposer%d" % period, 20),
}
# only calculate chunk root if it wouldn't be replaced anyway
if "chunk_root" not in explicit_params:
default_params["chunk_root"] = calc_chunk_root(default_params["body"])
params = merge(default_params, explicit_params)
header = CollationHeader(
shard_id=params["shard_id"],
chunk_root=params["chunk_root"],
period=params["period"],
proposer_address=params["proposer_address"],
)
collation = Collation(header, params["body"])
explicit_params = (yield collation) or {}
def _compute_modexp_gas_fee(data):
base_length, exponent_length, modulus_length = _extract_lengths(data)
first_32_exponent_bytes = zpad_right(
data[96 + base_length:96 + base_length + exponent_length],
to_size=min(exponent_length, 32),
)[:32]
adjusted_exponent_length = _compute_adjusted_exponent_length(
exponent_length,
first_32_exponent_bytes,
)
complexity = _compute_complexity(max(modulus_length, base_length))
gas_fee = (complexity * max(adjusted_exponent_length, 1) //
constants.GAS_MOD_EXP_QUADRATIC_DENOMINATOR)
return gas_fee
async def propose(self) -> Collation:
"""Broadcast a new collation to the network, add it to the local shard, and return it."""
# create collation for current period
period = self.get_current_period()
body = zpad_right(str(self).encode("utf-8"), COLLATION_SIZE)
header = CollationHeader(self.shard.shard_id, calc_chunk_root(body), period, b"\x11" * 20)
collation = Collation(header, body)
self.logger.debug("Proposing collation {}".format(collation))
# add collation to local chain
self.shard.add_collation(collation)
# broadcast collation
async for peer in self.peer_pool:
cast(ShardingProtocol, peer.sub_proto).send_new_collation_hashes(
[(collation.hash, collation.period)]
)
return collation
def test_blob_iteration(blobs, unpadded_body):
body = zpad_right(unpadded_body, COLLATION_SIZE)
deserialized_blobs = list(deserialize_blobs(body))
assert deserialized_blobs == blobs
def test_blob_serialization(blobs, unpadded_body):
assert serialize_blobs(blobs) == zpad_right(unpadded_body, COLLATION_SIZE)
async def test_collation_requests(request, event_loop):
# setup two peers
sender, receiver = await get_directly_linked_sharding_peers(
request, event_loop)
receiver_peer_pool = MockPeerPoolWithConnectedPeers([receiver])
# setup shard db for request receiving node
receiver_db = ShardDB(MemoryDB())
receiver_shard = Shard(receiver_db, 0)
# create three collations and add two to the shard of the receiver
# body is shared to avoid unnecessary chunk root calculation
body = zpad_right(b"body", COLLATION_SIZE)
chunk_root = calc_chunk_root(body)
c1 = Collation(
CollationHeader(0, chunk_root, 0, zpad_right(b"proposer1", 20)), body)
c2 = Collation(
CollationHeader(0, chunk_root, 1, zpad_right(b"proposer2", 20)), body)
c3 = Collation(
CollationHeader(0, chunk_root, 2, zpad_right(b"proposer3", 20)), body)
for collation in [c1, c2]:
receiver_shard.add_collation(collation)
# start shard syncer
receiver_syncer = ShardSyncer(receiver_shard, receiver_peer_pool)
asyncio.ensure_future(receiver_syncer.run())
def finalizer():
event_loop.run_until_complete(receiver_syncer.cancel())
request.addfinalizer(finalizer)
cancel_token = CancelToken("test")
# request single collation
received_collations = await asyncio.wait_for(
sender.get_collations([c1.hash], cancel_token),
timeout=1,
)
assert received_collations == set([c1])
# request multiple collations
received_collations = await asyncio.wait_for(
sender.get_collations([c1.hash, c2.hash], cancel_token),
timeout=1,
)
assert received_collations == set([c1, c2])
# request no collations
received_collations = await asyncio.wait_for(
sender.get_collations([], cancel_token),
timeout=1,
)
assert received_collations == set()
# request unknown collation
received_collations = await asyncio.wait_for(
sender.get_collations([c3.hash], cancel_token),
timeout=1,
)
assert received_collations == set()
# request multiple collations, including unknown one
received_collations = await asyncio.wait_for(
sender.get_collations([c1.hash, c2.hash, c3.hash], cancel_token),
timeout=1,
)
assert received_collations == set([c1, c2])
def calc_chunk_root(collation_body: bytes) -> Hash32:
check_body_size(collation_body)
chunks = list(iterate_chunks(collation_body))
return calc_merkle_root(chunks)
def check_body_size(body):
if len(body) != COLLATION_SIZE:
raise ValidationError("{} byte collation body exceeds maximum allowed size".format(
len(body)
))
return body
@apply_to_return_value(check_body_size)
@apply_to_return_value(lambda v: zpad_right(v, COLLATION_SIZE))
@apply_to_return_value(b"".join)
def serialize_blobs(blobs: Iterable[bytes]) -> Iterator[bytes]:
"""Serialize a sequence of blobs and return a collation body."""
for i, blob in enumerate(blobs):
if len(blob) == 0:
raise ValidationError("Cannot serialize blob {} of length 0".format(i))
if len(blob) > MAX_BLOB_SIZE:
raise ValidationError("Cannot serialize blob {} of size {}".format(i, len(blob)))
for blob_index in range(0, len(blob), CHUNK_DATA_SIZE):
remaining_blob_bytes = len(blob) - blob_index
if remaining_blob_bytes <= CHUNK_DATA_SIZE:
length_bits = remaining_blob_bytes
else:
