import RNS import os import bz2 import math import time import threading from .vendor import umsgpack as umsgpack from time import sleep class Resource: """ The Resource class allows transferring arbitrary amounts of data over a link. It will automatically handle sequencing, compression, coordination and checksumming. :param data: The data to be transferred. Can be *bytes* or an open *file handle*. See the :ref:`Filetransfer Example` for details. :param link: The :ref:`RNS.Link` instance on which to transfer the data. :param advertise: Whether to automatically advertise the resource. Can be *True* or *False*. :param auto_compress: Whether to auto-compress the resource. Can be *True* or *False*. :param callback: A *callable* with the signature *callback(resource)*. Will be called when the resource transfer concludes. :param progress_callback: A *callable* with the signature *callback(resource)*. Will be called whenever the resource transfer progress is updated. :param segment_index: Internal use, ignore. :param original_hash: Internal use, ignore. """ WINDOW_FLEXIBILITY = 4 WINDOW_MIN = 1 WINDOW_MAX = 10 WINDOW = 4 MAPHASH_LEN = 4 SDU = RNS.Packet.MDU RANDOM_HASH_SIZE = 4 # This is an indication of what the # maximum size a resource should be, if # it is to be handled within reasonable # time constraint, even on small systems. # A small system in this regard is # defined as a Raspberry Pi, which should # be able to compress, encrypt and hash-map # the resource in about 10 seconds. # This constant will be used when determining # how to sequence the sending of large resources. MAX_EFFICIENT_SIZE = 16 * 1024 * 1024 # The maximum size to auto-compress with # bz2 before sending. AUTO_COMPRESS_MAX_SIZE = MAX_EFFICIENT_SIZE # TODO: Should be allocated more # intelligently # TODO: Set higher MAX_RETRIES = 5 SENDER_GRACE_TIME = 10 RETRY_GRACE_TIME = 0.25 HASHMAP_IS_NOT_EXHAUSTED = 0x00 HASHMAP_IS_EXHAUSTED = 0xFF # Status constants NONE = 0x00 QUEUED = 0x01 ADVERTISED = 0x02 TRANSFERRING = 0x03 AWAITING_PROOF = 0x04 ASSEMBLING = 0x05 COMPLETE = 0x06 FAILED = 0x07 CORRUPT = 0x08 @staticmethod def accept(advertisement_packet, callback=None, progress_callback = None): try: adv = ResourceAdvertisement.unpack(advertisement_packet.plaintext) resource = Resource(None, advertisement_packet.link) resource.status = Resource.TRANSFERRING resource.flags = adv.f resource.size = adv.t resource.total_size = adv.d resource.uncompressed_size = adv.d resource.hash = adv.h resource.original_hash = adv.o resource.random_hash = adv.r resource.hashmap_raw = adv.m resource.encrypted = True if resource.flags & 0x01 else False resource.compressed = True if resource.flags >> 1 & 0x01 else False resource.initiator = False resource.callback = callback resource.__progress_callback = progress_callback resource.total_parts = int(math.ceil(resource.size/float(Resource.SDU))) resource.received_count = 0 resource.outstanding_parts = 0 resource.parts = [None] * resource.total_parts resource.window = Resource.WINDOW resource.window_max = Resource.WINDOW_MAX resource.window_min = Resource.WINDOW_MIN resource.window_flexibility = Resource.WINDOW_FLEXIBILITY resource.last_activity = time.time() resource.storagepath = RNS.Reticulum.resourcepath+"/"+resource.original_hash.hex() resource.segment_index = adv.i resource.total_segments = adv.l if adv.l > 1: resource.split = True else: resource.split = False resource.hashmap = [None] * resource.total_parts resource.hashmap_height = 0 resource.waiting_for_hmu = False resource.receiving_part = False resource.consecutive_completed_height = 0 resource.link.register_incoming_resource(resource) RNS.log("Accepting resource advertisement for "+RNS.prettyhexrep(resource.hash), RNS.LOG_DEBUG) resource.link.callbacks.resource_started(resource) resource.hashmap_update(0, resource.hashmap_raw) resource.watchdog_job() return resource except Exception as e: RNS.log("Could not decode resource advertisement, dropping resource", RNS.LOG_DEBUG) return None # Create a resource for transmission to a remote destination # The data passed can be either a bytes-array or a file opened # in binary read mode. def __init__(self, data, link, advertise=True, auto_compress=True, callback=None, progress_callback=None, segment_index = 1, original_hash = None): data_size = None resource_data = None if hasattr(data, "read"): data_size = os.stat(data.name).st_size self.total_size = data_size self.grand_total_parts = math.ceil(data_size/Resource.SDU) if data_size <= Resource.MAX_EFFICIENT_SIZE: self.total_segments = 1 self.segment_index = 1 self.split = False resource_data = data.read() data.close() else: self.total_segments = ((data_size-1)//Resource.MAX_EFFICIENT_SIZE)+1 self.segment_index = segment_index self.split = True seek_index = segment_index-1 seek_position = seek_index*Resource.MAX_EFFICIENT_SIZE data.seek(seek_position) resource_data = data.read(Resource.MAX_EFFICIENT_SIZE) self.input_file = data elif isinstance(data, bytes): data_size = len(data) self.grand_total_parts = math.ceil(data_size/Resource.SDU) self.total_size = data_size resource_data = data self.total_segments = 1 self.segment_index = 1 self.split = False elif data == None: pass else: raise TypeError("Invalid data instance type passed to resource initialisation") data = resource_data self.status = Resource.NONE self.link = link self.max_retries = Resource.MAX_RETRIES self.retries_left = self.max_retries self.default_timeout = self.link.default_timeout self.timeout_factor = self.link.timeout_factor self.sender_grace_time = Resource.SENDER_GRACE_TIME self.hmu_retry_ok = False self.watchdog_lock = False self.__watchdog_job_id = 0 self.__progress_callback = progress_callback self.rtt = None self.receiver_min_consecutive_height = 0 if data != None: self.initiator = True self.callback = callback self.uncompressed_data = data compression_began = time.time() if (auto_compress and len(self.uncompressed_data) < Resource.AUTO_COMPRESS_MAX_SIZE): RNS.log("Compressing resource data...", RNS.LOG_DEBUG) self.compressed_data = bz2.compress(self.uncompressed_data) RNS.log("Compression completed in "+str(round(time.time()-compression_began, 3))+" seconds", RNS.LOG_DEBUG) else: self.compressed_data = self.uncompressed_data self.uncompressed_size = len(self.uncompressed_data) self.compressed_size = len(self.compressed_data) if (self.compressed_size < self.uncompressed_size and auto_compress): saved_bytes = len(self.uncompressed_data) - len(self.compressed_data) RNS.log("Compression saved "+str(saved_bytes)+" bytes, sending compressed", RNS.LOG_DEBUG) self.data = b"" self.data += RNS.Identity.get_random_hash()[:Resource.RANDOM_HASH_SIZE] self.data += self.compressed_data self.compressed = True self.uncompressed_data = None else: self.data = b"" self.data += RNS.Identity.get_random_hash()[:Resource.RANDOM_HASH_SIZE] self.data += self.uncompressed_data self.uncompressed_data = self.data self.compressed = False self.compressed_data = None if auto_compress: RNS.log("Compression did not decrease size, sending uncompressed", RNS.LOG_DEBUG) # Resources handle encryption directly to # make optimal use of packet MTU on an entire # encrypted stream. The Resource instance will # use it's underlying link directly to encrypt. if not self.link.encryption_disabled(): self.data = self.link.encrypt(self.data) self.encrypted = True else: self.encrypted = False self.size = len(self.data) self.sent_parts = 0 hashmap_entries = int(math.ceil(self.size/float(Resource.SDU))) hashmap_ok = False while not hashmap_ok: hashmap_computation_began = time.time() RNS.log("Starting resource hashmap computation with "+str(hashmap_entries)+" entries...", RNS.LOG_DEBUG) self.random_hash = RNS.Identity.get_random_hash()[:Resource.RANDOM_HASH_SIZE] self.hash = RNS.Identity.full_hash(data+self.random_hash) self.expected_proof = RNS.Identity.full_hash(data+self.hash) if original_hash == None: self.original_hash = self.hash else: self.original_hash = original_hash self.parts = [] self.hashmap = b"" collision_guard_list = [] for i in range(0,hashmap_entries): data = self.data[i*Resource.SDU:(i+1)*Resource.SDU] map_hash = self.get_map_hash(data) if map_hash in collision_guard_list: RNS.log("Found hash collision in resource map, remapping...", RNS.LOG_VERBOSE) hashmap_ok = False break else: hashmap_ok = True collision_guard_list.append(map_hash) if len(collision_guard_list) > ResourceAdvertisement.COLLISION_GUARD_SIZE: collision_guard_list.pop(0) part = RNS.Packet(link, data, context=RNS.Packet.RESOURCE) part.pack() part.map_hash = map_hash self.hashmap += part.map_hash self.parts.append(part) RNS.log("Hashmap computation concluded in "+str(round(time.time()-hashmap_computation_began, 3))+" seconds", RNS.LOG_DEBUG) if advertise: self.advertise() else: pass def hashmap_update_packet(self, plaintext): if not self.status == Resource.FAILED: self.last_activity = time.time() self.retries_left = self.max_retries update = umsgpack.unpackb(plaintext[RNS.Identity.HASHLENGTH//8:]) self.hashmap_update(update[0], update[1]) def hashmap_update(self, segment, hashmap): if not self.status == Resource.FAILED: self.status = Resource.TRANSFERRING seg_len = ResourceAdvertisement.HASHMAP_MAX_LEN hashes = len(hashmap)//Resource.MAPHASH_LEN for i in range(0,hashes): if self.hashmap[i+segment*seg_len] == None: self.hashmap_height += 1 self.hashmap[i+segment*seg_len] = hashmap[i*Resource.MAPHASH_LEN:(i+1)*Resource.MAPHASH_LEN] self.waiting_for_hmu = False self.request_next() def get_map_hash(self, data): # TODO: This will break if running unencrypted, # uncompressed transfers on streams with long blocks # of identical bytes. Doing so would be very silly # anyways but maybe it should be handled gracefully. return RNS.Identity.full_hash(data+self.random_hash)[:Resource.MAPHASH_LEN] def advertise(self): """ Advertise the resource. If the other end of the link accepts the resource advertisement it will begin transferring. """ thread = threading.Thread(target=self.__advertise_job) thread.setDaemon(True) thread.start() def __advertise_job(self): data = ResourceAdvertisement(self).pack() self.advertisement_packet = RNS.Packet(self.link, data, context=RNS.Packet.RESOURCE_ADV) while not self.link.ready_for_new_resource(): self.status = Resource.QUEUED sleep(0.25) try: self.advertisement_packet.send() self.last_activity = time.time() self.adv_sent = self.last_activity self.rtt = None self.status = Resource.ADVERTISED self.link.register_outgoing_resource(self) RNS.log("Sent resource advertisement for "+RNS.prettyhexrep(self.hash), RNS.LOG_DEBUG) except Exception as e: RNS.log("Could not advertise resource, the contained exception was: "+str(e), RNS.LOG_ERROR) self.cancel() return self.watchdog_job() def watchdog_job(self): thread = threading.Thread(target=self.__watchdog_job) thread.setDaemon(True) thread.start() def __watchdog_job(self): self.__watchdog_job_id += 1 this_job_id = self.__watchdog_job_id while self.status < Resource.ASSEMBLING and this_job_id == self.__watchdog_job_id: while self.watchdog_lock: sleep(0.025) sleep_time = None if self.status == Resource.ADVERTISED: sleep_time = (self.adv_sent+self.default_timeout)-time.time() if sleep_time < 0: if self.retries_left <= 0: RNS.log("Resource transfer timeout after sending advertisement", RNS.LOG_DEBUG) self.cancel() sleep_time = 0.001 else: try: RNS.log("No part requests received, retrying resource advertisement...", RNS.LOG_DEBUG) self.retries_left -= 1 self.advertisement_packet.resend() self.last_activity = time.time() self.adv_sent = self.last_activity sleep_time = 0.001 except Exception as e: RNS.log("Could not resend advertisement packet, cancelling resource", RNS.LOG_VERBOSE) self.cancel() elif self.status == Resource.TRANSFERRING: if not self.initiator: rtt = self.link.rtt if self.rtt == None else self.rtt sleep_time = self.last_activity + (rtt*self.timeout_factor) + Resource.RETRY_GRACE_TIME - time.time() if sleep_time < 0: if self.retries_left > 0: RNS.log("Timed out waiting for parts, requesting retry", RNS.LOG_DEBUG) if self.window > self.window_min: self.window -= 1 if self.window_max > self.window_min: self.window_max -= 1 if (self.window_max - self.window) > (self.window_flexibility-1): self.window_max -= 1 sleep_time = 0.001 self.retries_left -= 1 self.waiting_for_hmu = False self.request_next() else: self.cancel() sleep_time = 0.001 else: max_wait = self.rtt * self.timeout_factor * self.max_retries + self.sender_grace_time sleep_time = self.last_activity + max_wait - time.time() if sleep_time < 0: RNS.log("Resource timed out waiting for part requests", RNS.LOG_DEBUG) self.cancel() sleep_time = 0.001 elif self.status == Resource.AWAITING_PROOF: sleep_time = self.last_part_sent + (self.rtt*self.timeout_factor+self.sender_grace_time) - time.time() if sleep_time < 0: if self.retries_left <= 0: RNS.log("Resource timed out waiting for proof", RNS.LOG_DEBUG) self.cancel() sleep_time = 0.001 else: RNS.log("All parts sent, but no resource proof received, querying network cache...", RNS.LOG_DEBUG) self.retries_left -= 1 expected_data = self.hash + self.expected_proof expected_proof_packet = RNS.Packet(self.link, expected_data, packet_type=RNS.Packet.PROOF, context=RNS.Packet.RESOURCE_PRF) expected_proof_packet.pack() RNS.Transport.cache_request(expected_proof_packet.packet_hash, self.link) self.last_part_sent = time.time() sleep_time = 0.001 if sleep_time == 0: RNS.log("Warning! Link watchdog sleep time of 0!", RNS.LOG_WARNING) if sleep_time == None or sleep_time < 0: RNS.log("Timing error, cancelling resource transfer.", RNS.LOG_ERROR) self.cancel() if sleep_time != None: sleep(sleep_time) def assemble(self): if not self.status == Resource.FAILED: try: self.status = Resource.ASSEMBLING stream = b"".join(self.parts) if self.encrypted: data = self.link.decrypt(stream) else: data = stream # Strip off random hash data = data[Resource.RANDOM_HASH_SIZE:] if self.compressed: self.data = bz2.decompress(data) else: self.data = data calculated_hash = RNS.Identity.full_hash(self.data+self.random_hash) if calculated_hash == self.hash: self.file = open(self.storagepath, "ab") self.file.write(self.data) self.file.close() self.status = Resource.COMPLETE self.prove() else: self.status = Resource.CORRUPT except Exception as e: RNS.log("Error while assembling received resource.", RNS.LOG_ERROR) RNS.log("The contained exception was: "+str(e), RNS.LOG_ERROR) self.status = Resource.CORRUPT self.link.resource_concluded(self) if self.segment_index == self.total_segments: if self.callback != None: self.data = open(self.storagepath, "rb") self.callback(self) try: self.data.close() os.unlink(self.storagepath) except Exception as e: RNS.log("Error while cleaning up resource files, the contained exception was:", RNS.LOG_ERROR) RNS.log(str(e)) else: RNS.log("Resource segment "+str(self.segment_index)+" of "+str(self.total_segments)+" received, waiting for next segment to be announced", RNS.LOG_DEBUG) def prove(self): if not self.status == Resource.FAILED: try: proof = RNS.Identity.full_hash(self.data+self.hash) proof_data = self.hash+proof proof_packet = RNS.Packet(self.link, proof_data, packet_type=RNS.Packet.PROOF, context=RNS.Packet.RESOURCE_PRF) proof_packet.send() except Exception as e: RNS.log("Could not send proof packet, cancelling resource", RNS.LOG_DEBUG) RNS.log("The contained exception was: "+str(e), RNS.LOG_DEBUG) self.cancel() def validate_proof(self, proof_data): if not self.status == Resource.FAILED: if len(proof_data) == RNS.Identity.HASHLENGTH//8*2: if proof_data[RNS.Identity.HASHLENGTH//8:] == self.expected_proof: self.status = Resource.COMPLETE self.link.resource_concluded(self) if self.segment_index == self.total_segments: # If all segments were processed, we'll # signal that the resource sending concluded if self.callback != None: self.callback(self) else: # Otherwise we'll recursively create the # next segment of the resource Resource(self.input_file, self.link, callback = self.callback, segment_index = self.segment_index+1, original_hash=self.original_hash) else: pass else: pass def receive_part(self, packet): while self.receiving_part: sleep(0.001) self.receiving_part = True self.last_activity = time.time() self.retries_left = self.max_retries if self.req_resp == None: self.req_resp = self.last_activity rtt = self.req_resp-self.req_sent if self.rtt == None: self.rtt = rtt self.watchdog_job() elif self.rtt < rtt: self.rtt = rtt if not self.status == Resource.FAILED: self.status = Resource.TRANSFERRING part_data = packet.data part_hash = self.get_map_hash(part_data) i = self.consecutive_completed_height for map_hash in self.hashmap[self.consecutive_completed_height:self.consecutive_completed_height+self.window]: if map_hash == part_hash: if self.parts[i] == None: # Insert data into parts list self.parts[i] = part_data self.received_count += 1 self.outstanding_parts -= 1 # Update consecutive completed pointer if i == self.consecutive_completed_height + 1: self.consecutive_completed_height = i cp = self.consecutive_completed_height + 1 while cp < len(self.parts) and self.parts[cp] != None: self.consecutive_completed_height = cp cp += 1 i += 1 self.receiving_part = False if self.__progress_callback != None: self.__progress_callback(self) if self.outstanding_parts == 0 and self.received_count == self.total_parts: self.assemble() elif self.outstanding_parts == 0: # TODO: Figure out if there is a mathematically # optimal way to adjust windows if self.window < self.window_max: self.window += 1 if (self.window - self.window_min) > (self.window_flexibility-1): self.window_min += 1 self.request_next() else: self.receiving_part = False # Called on incoming resource to send a request for more data def request_next(self): while self.receiving_part: sleep(0.001) if not self.status == Resource.FAILED: if not self.waiting_for_hmu: self.outstanding_parts = 0 hashmap_exhausted = Resource.HASHMAP_IS_NOT_EXHAUSTED requested_hashes = b"" offset = (1 if self.consecutive_completed_height > 0 else 0) i = 0; pn = self.consecutive_completed_height+offset search_start = pn for part in self.parts[search_start:search_start+self.window]: if part == None: part_hash = self.hashmap[pn] if part_hash != None: requested_hashes += part_hash self.outstanding_parts += 1 i += 1 else: hashmap_exhausted = Resource.HASHMAP_IS_EXHAUSTED pn += 1 if i >= self.window or hashmap_exhausted == Resource.HASHMAP_IS_EXHAUSTED: break hmu_part = bytes([hashmap_exhausted]) if hashmap_exhausted == Resource.HASHMAP_IS_EXHAUSTED: last_map_hash = self.hashmap[self.hashmap_height-1] hmu_part += last_map_hash self.waiting_for_hmu = True requested_data = b"" request_data = hmu_part + self.hash + requested_hashes request_packet = RNS.Packet(self.link, request_data, context = RNS.Packet.RESOURCE_REQ) try: request_packet.send() self.last_activity = time.time() self.req_sent = self.last_activity self.req_resp = None except Exception as e: RNS.log("Could not send resource request packet, cancelling resource", RNS.LOG_DEBUG) RNS.log("The contained exception was: "+str(e), RNS.LOG_DEBUG) self.cancel() # Called on outgoing resource to make it send more data def request(self, request_data): if not self.status == Resource.FAILED: rtt = time.time() - self.adv_sent if self.rtt == None: self.rtt = rtt if self.status != Resource.TRANSFERRING: self.status = Resource.TRANSFERRING self.watchdog_job() self.retries_left = self.max_retries wants_more_hashmap = True if request_data[0] == Resource.HASHMAP_IS_EXHAUSTED else False pad = 1+Resource.MAPHASH_LEN if wants_more_hashmap else 1 requested_hashes = request_data[pad+RNS.Identity.HASHLENGTH//8:] for i in range(0,len(requested_hashes)//Resource.MAPHASH_LEN): requested_hash = requested_hashes[i*Resource.MAPHASH_LEN:(i+1)*Resource.MAPHASH_LEN] search_start = self.receiver_min_consecutive_height search_end = self.receiver_min_consecutive_height+ResourceAdvertisement.COLLISION_GUARD_SIZE for part in self.parts[search_start:search_end]: if part.map_hash == requested_hash: try: if not part.sent: part.send() self.sent_parts += 1 else: part.resend() self.last_activity = time.time() self.last_part_sent = self.last_activity break except Exception as e: RNS.log("Resource could not send parts, cancelling transfer!", RNS.LOG_DEBUG) RNS.log("The contained exception was: "+str(e), RNS.LOG_DEBUG) self.cancel() if wants_more_hashmap: last_map_hash = request_data[1:Resource.MAPHASH_LEN+1] part_index = self.receiver_min_consecutive_height search_start = part_index search_end = self.receiver_min_consecutive_height+ResourceAdvertisement.COLLISION_GUARD_SIZE for part in self.parts[search_start:search_end]: part_index += 1 if part.map_hash == last_map_hash: break self.receiver_min_consecutive_height = max(part_index-1-Resource.WINDOW_MAX, 0) if part_index % ResourceAdvertisement.HASHMAP_MAX_LEN != 0: RNS.log("Resource sequencing error, cancelling transfer!", RNS.LOG_ERROR) self.cancel() else: segment = part_index // ResourceAdvertisement.HASHMAP_MAX_LEN hashmap_start = segment*ResourceAdvertisement.HASHMAP_MAX_LEN hashmap_end = min((segment+1)*ResourceAdvertisement.HASHMAP_MAX_LEN, len(self.parts)) hashmap = b"" for i in range(hashmap_start,hashmap_end): hashmap += self.hashmap[i*Resource.MAPHASH_LEN:(i+1)*Resource.MAPHASH_LEN] hmu = self.hash+umsgpack.packb([segment, hashmap]) hmu_packet = RNS.Packet(self.link, hmu, context = RNS.Packet.RESOURCE_HMU) try: hmu_packet.send() self.last_activity = time.time() except Exception as e: RNS.log("Could not send resource HMU packet, cancelling resource", RNS.LOG_DEBUG) RNS.log("The contained exception was: "+str(e), RNS.LOG_DEBUG) self.cancel() if self.sent_parts == len(self.parts): self.status = Resource.AWAITING_PROOF if self.__progress_callback != None: self.__progress_callback(self) def cancel(self): """ Cancels transferring the resource. """ if self.status < Resource.COMPLETE: self.status = Resource.FAILED if self.initiator: if self.link.status == RNS.Link.ACTIVE: try: cancel_packet = RNS.Packet(self.link, self.hash, context=RNS.Packet.RESOURCE_ICL) cancel_packet.send() except Exception as e: RNS.log("Could not send resource cancel packet, the contained exception was: "+str(e), RNS.LOG_ERROR) self.link.cancel_outgoing_resource(self) else: self.link.cancel_incoming_resource(self) if self.callback != None: self.link.resource_concluded(self) self.callback(self) def progress_callback(self, callback): self.__progress_callback = callback def progress(self): """ :returns: The current progress of the resource transfer as a *float* between 0.0 and 1.0. """ if self.initiator: self.processed_parts = (self.segment_index-1)*math.ceil(Resource.MAX_EFFICIENT_SIZE/Resource.SDU) self.processed_parts += self.sent_parts self.progress_total_parts = float(self.grand_total_parts) else: self.processed_parts = (self.segment_index-1)*math.ceil(Resource.MAX_EFFICIENT_SIZE/Resource.SDU) self.processed_parts += self.received_count if self.split: self.progress_total_parts = float(math.ceil(self.total_size/Resource.SDU)) else: self.progress_total_parts = float(self.total_parts) progress = self.processed_parts / self.progress_total_parts return progress def __str__(self): return RNS.prettyhexrep(self.hash)+str(self.link) class ResourceAdvertisement: HASHMAP_MAX_LEN = 73 COLLISION_GUARD_SIZE = 2*Resource.WINDOW_MAX+HASHMAP_MAX_LEN def __init__(self, resource=None): if resource != None: self.t = resource.size # Transfer size self.d = resource.total_size # Total uncompressed data size self.n = len(resource.parts) # Number of parts self.h = resource.hash # Resource hash self.r = resource.random_hash # Resource random hash self.o = resource.original_hash # First-segment hash self.m = resource.hashmap # Resource hashmap self.c = resource.compressed # Compression flag self.e = resource.encrypted # Encryption flag self.s = resource.split # Split flag self.i = resource.segment_index # Segment index self.l = resource.total_segments # Total segments self.f = 0x00 | self.s << 2 | self.c << 1 | self.e # Flags def pack(self, segment=0): hashmap_start = segment*ResourceAdvertisement.HASHMAP_MAX_LEN hashmap_end = min((segment+1)*(ResourceAdvertisement.HASHMAP_MAX_LEN), self.n) hashmap = b"" for i in range(hashmap_start,hashmap_end): hashmap += self.m[i*Resource.MAPHASH_LEN:(i+1)*Resource.MAPHASH_LEN] dictionary = { "t": self.t, # Transfer size "d": self.d, # Data size "n": self.n, # Number of parts "h": self.h, # Resource hash "r": self.r, # Resource random hash "o": self.o, # Original hash "i": self.i, # Segment index "l": self.l, # Total segments "f": self.f, # Resource flags "m": hashmap } return umsgpack.packb(dictionary) @staticmethod def unpack(data): dictionary = umsgpack.unpackb(data) adv = ResourceAdvertisement() adv.t = dictionary["t"] adv.d = dictionary["d"] adv.n = dictionary["n"] adv.h = dictionary["h"] adv.r = dictionary["r"] adv.o = dictionary["o"] adv.m = dictionary["m"] adv.f = dictionary["f"] adv.i = dictionary["i"] adv.l = dictionary["l"] adv.e = True if (adv.f & 0x01) == 0x01 else False adv.c = True if ((adv.f >> 1) & 0x01) == 0x01 else False adv.s = True if ((adv.f >> 2) & 0x01) == 0x01 else False return adv