from cryptography.hazmat.backends import default_backend from cryptography.hazmat.primitives import hashes from cryptography.hazmat.primitives import serialization from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PrivateKey, Ed25519PublicKey from cryptography.hazmat.primitives.asymmetric.x25519 import X25519PrivateKey, X25519PublicKey from cryptography.hazmat.primitives.kdf.hkdf import HKDF from cryptography.fernet import Fernet from time import sleep from .vendor import umsgpack as umsgpack import threading import base64 import math import time import RNS import traceback class LinkCallbacks: def __init__(self): self.link_established = None self.link_closed = None self.packet = None self.resource = None self.resource_started = None self.resource_concluded = None self.remote_identified = None class Link: """ This class is used to establish and manage links to other peers. When a link instance is created, Reticulum will attempt to establish verified connectivity with the specified destination. :param destination: A :ref:`RNS.Destination` instance which to establish a link to. :param established_callback: An optional function or method with the signature *callback(link)* to be called when the link has been established. :param closed_callback: An optional function or method with the signature *callback(link)* to be called when the link is closed. """ CURVE = RNS.Identity.CURVE """ The curve used for Elliptic Curve DH key exchanges """ ECPUBSIZE = 32+32 KEYSIZE = 32 MDU = math.floor((RNS.Reticulum.MTU-RNS.Reticulum.HEADER_MINSIZE-RNS.Identity.FERNET_OVERHEAD)/RNS.Identity.AES128_BLOCKSIZE)*RNS.Identity.AES128_BLOCKSIZE - 1 # This value is set at a reasonable # level for a 1 Kb/s channel. ESTABLISHMENT_TIMEOUT_PER_HOP = 5 """ Default timeout for link establishment in seconds per hop to destination. """ TRAFFIC_TIMEOUT_FACTOR = 6 KEEPALIVE_TIMEOUT_FACTOR = 4 STALE_GRACE = 2 KEEPALIVE = 360 """ Interval for sending keep-alive packets on established links in seconds. """ PENDING = 0x00 HANDSHAKE = 0x01 ACTIVE = 0x02 STALE = 0x03 CLOSED = 0x04 TIMEOUT = 0x01 INITIATOR_CLOSED = 0x02 DESTINATION_CLOSED = 0x03 ACCEPT_NONE = 0x00 ACCEPT_APP = 0x01 ACCEPT_ALL = 0x02 resource_strategies = [ACCEPT_NONE, ACCEPT_APP, ACCEPT_ALL] @staticmethod def validate_request(owner, data, packet): if len(data) == (Link.ECPUBSIZE): try: link = Link(owner = owner, peer_pub_bytes=data[:Link.ECPUBSIZE//2], peer_sig_pub_bytes=data[Link.ECPUBSIZE//2:Link.ECPUBSIZE]) link.set_link_id(packet) link.destination = packet.destination link.establishment_timeout = Link.ESTABLISHMENT_TIMEOUT_PER_HOP * max(1, packet.hops) RNS.log("Validating link request "+RNS.prettyhexrep(link.link_id), RNS.LOG_VERBOSE) link.handshake() link.attached_interface = packet.receiving_interface link.prove() link.request_time = time.time() RNS.Transport.register_link(link) link.last_inbound = time.time() link.start_watchdog() RNS.log("Incoming link request "+str(link)+" accepted", RNS.LOG_VERBOSE) return link except Exception as e: RNS.log("Validating link request failed", RNS.LOG_VERBOSE) traceback.print_exc() return None else: RNS.log("Invalid link request payload size, dropping request", RNS.LOG_VERBOSE) return None def __init__(self, destination=None, established_callback = None, closed_callback = None, owner=None, peer_pub_bytes = None, peer_sig_pub_bytes = None): if destination != None and destination.type != RNS.Destination.SINGLE: raise TypeError("Links can only be established to the \"single\" destination type") self.rtt = None self.callbacks = LinkCallbacks() self.resource_strategy = Link.ACCEPT_NONE self.outgoing_resources = [] self.incoming_resources = [] self.pending_requests = [] self.last_inbound = 0 self.last_outbound = 0 self.tx = 0 self.rx = 0 self.txbytes = 0 self.rxbytes = 0 self.traffic_timeout_factor = Link.TRAFFIC_TIMEOUT_FACTOR self.keepalive_timeout_factor = Link.KEEPALIVE_TIMEOUT_FACTOR self.keepalive = Link.KEEPALIVE self.watchdog_lock = False self.status = Link.PENDING self.type = RNS.Destination.LINK self.owner = owner self.destination = destination self.attached_interface = None self.__remote_identity = None if self.destination == None: self.initiator = False self.prv = self.owner.identity.prv self.sig_prv = self.owner.identity.sig_prv else: self.initiator = True self.establishment_timeout = Link.ESTABLISHMENT_TIMEOUT_PER_HOP * max(1, RNS.Transport.hops_to(destination.hash)) self.prv = X25519PrivateKey.generate() self.sig_prv = Ed25519PrivateKey.generate() self.fernet = None self.pub = self.prv.public_key() self.pub_bytes = self.pub.public_bytes( encoding=serialization.Encoding.Raw, format=serialization.PublicFormat.Raw ) self.sig_pub = self.sig_prv.public_key() self.sig_pub_bytes = self.sig_pub.public_bytes( encoding=serialization.Encoding.Raw, format=serialization.PublicFormat.Raw ) if peer_pub_bytes == None: self.peer_pub = None self.peer_pub_bytes = None else: self.load_peer(peer_pub_bytes, peer_sig_pub_bytes) if established_callback != None: self.set_link_established_callback(established_callback) if closed_callback != None: self.set_link_closed_callback(closed_callback) if (self.initiator): peer_pub_bytes = self.destination.identity.get_public_key()[:Link.ECPUBSIZE//2] peer_sig_pub_bytes = self.destination.identity.get_public_key()[Link.ECPUBSIZE//2:Link.ECPUBSIZE] self.request_data = self.pub_bytes+self.sig_pub_bytes self.packet = RNS.Packet(destination, self.request_data, packet_type=RNS.Packet.LINKREQUEST) self.packet.pack() self.set_link_id(self.packet) self.load_peer(peer_pub_bytes, peer_sig_pub_bytes) self.handshake() RNS.Transport.register_link(self) self.request_time = time.time() self.start_watchdog() self.packet.send() self.had_outbound() RNS.log("Link request "+RNS.prettyhexrep(self.link_id)+" sent to "+str(self.destination), RNS.LOG_VERBOSE) def load_peer(self, peer_pub_bytes, peer_sig_pub_bytes): self.peer_pub_bytes = peer_pub_bytes self.peer_pub = X25519PublicKey.from_public_bytes(self.peer_pub_bytes) self.peer_sig_pub_bytes = peer_sig_pub_bytes self.peer_sig_pub = Ed25519PublicKey.from_public_bytes(self.peer_sig_pub_bytes) if not hasattr(self.peer_pub, "curve"): self.peer_pub.curve = Link.CURVE def set_link_id(self, packet): self.link_id = packet.getTruncatedHash() self.hash = self.link_id def handshake(self): self.status = Link.HANDSHAKE self.shared_key = self.prv.exchange(self.peer_pub) self.derived_key = HKDF( algorithm=hashes.SHA256(), length=32, salt=self.get_salt(), info=self.get_context(), ).derive(self.shared_key) def prove(self): signed_data = self.link_id+self.pub_bytes+self.sig_pub_bytes signature = self.owner.identity.sign(signed_data) proof_data = signature proof = RNS.Packet(self, proof_data, packet_type=RNS.Packet.PROOF, context=RNS.Packet.LRPROOF) proof.send() self.had_outbound() def prove_packet(self, packet): signature = self.sign(packet.packet_hash) # TODO: Hardcoded as explicit proof for now # if RNS.Reticulum.should_use_implicit_proof(): # proof_data = signature # else: # proof_data = packet.packet_hash + signature proof_data = packet.packet_hash + signature proof = RNS.Packet(self, proof_data, RNS.Packet.PROOF) proof.send() self.had_outbound() def validate_proof(self, packet): if self.initiator and len(packet.data) == RNS.Identity.SIGLENGTH//8: signed_data = self.link_id+self.peer_pub_bytes+self.peer_sig_pub_bytes signature = packet.data[:RNS.Identity.SIGLENGTH//8] if self.destination.identity.validate(signature, signed_data): self.rtt = time.time() - self.request_time self.attached_interface = packet.receiving_interface self.__remote_identity = self.destination.identity RNS.Transport.activate_link(self) RNS.log("Link "+str(self)+" established with "+str(self.destination)+", RTT is "+str(self.rtt), RNS.LOG_VERBOSE) rtt_data = umsgpack.packb(self.rtt) rtt_packet = RNS.Packet(self, rtt_data, context=RNS.Packet.LRRTT) rtt_packet.send() self.had_outbound() self.status = Link.ACTIVE if self.callbacks.link_established != None: thread = threading.Thread(target=self.callbacks.link_established, args=(self,)) thread.setDaemon(True) thread.start() else: RNS.log("Invalid link proof signature received by "+str(self)+". Ignoring.", RNS.LOG_DEBUG) def identify(self, identity): """ Identifies the initiator of the link to the remote peer. This can only happen once the link has been established, and is carried out over the encrypted link. The identity is only revealed to the remote peer, and initiator anonymity is thus preserved. This method can be used for authentication. :param identity: An RNS.Identity instance to identify as. """ if self.initiator: signed_data = self.link_id + identity.get_public_key() signature = identity.sign(signed_data) proof_data = identity.get_public_key() + signature proof = RNS.Packet(self, proof_data, RNS.Packet.DATA, context = RNS.Packet.LINKIDENTIFY) proof.send() self.had_outbound() def request(self, path, data = None, response_callback = None, failed_callback = None, progress_callback = None, timeout = None): """ Sends a request to the remote peer. :param path: The request path. :param response_callback: An optional function or method with the signature *response_callback(request_receipt)* to be called when a response is received. See the :ref:`Request Example` for more info. :param failed_callback: An optional function or method with the signature *failed_callback(request_receipt)* to be called when a request fails. See the :ref:`Request Example` for more info. :param progress_callback: An optional function or method with the signature *progress_callback(request_receipt)* to be called when progress is made receiving the response. Progress can be accessed as a float between 0.0 and 1.0 by the *request_receipt.progress* property. :param timeout: An optional timeout in seconds for the request. If *None* is supplied it will be calculated based on link RTT. :returns: A :ref:`RNS.RequestReceipt` instance if the request was sent, or *False* if it was not. """ request_path_hash = RNS.Identity.truncated_hash(path.encode("utf-8")) unpacked_request = [time.time(), request_path_hash, data] packed_request = umsgpack.packb(unpacked_request) if timeout == None: timeout = self.rtt * self.traffic_timeout_factor if len(packed_request) <= Link.MDU: request_packet = RNS.Packet(self, packed_request, RNS.Packet.DATA, context = RNS.Packet.REQUEST) packet_receipt = request_packet.send() if packet_receipt == False: return False else: packet_receipt.set_timeout(timeout) return RequestReceipt( self, packet_receipt = packet_receipt, response_callback = response_callback, failed_callback = failed_callback, progress_callback = progress_callback, timeout = timeout ) else: request_id = RNS.Identity.truncated_hash(packed_request) RNS.log("Sending request "+RNS.prettyhexrep(request_id)+" as resource.", RNS.LOG_DEBUG) request_resource = RNS.Resource(packed_request, self, request_id = request_id, is_response = False, timeout = timeout) return RequestReceipt( self, resource = request_resource, response_callback = response_callback, failed_callback = failed_callback, progress_callback = progress_callback, timeout = timeout ) def rtt_packet(self, packet): try: # TODO: This is crude, we should use the delta # to model a more representative per-bit round # trip time, and use that to set a sensible RTT # expectancy for the link. This will have to do # for now though. measured_rtt = time.time() - self.request_time plaintext = self.decrypt(packet.data) rtt = umsgpack.unpackb(plaintext) self.rtt = max(measured_rtt, rtt) self.status = Link.ACTIVE if self.owner.callbacks.link_established != None: self.owner.callbacks.link_established(self) except Exception as e: RNS.log("Error occurred while processing RTT packet, tearing down link. The contained exception was: "+str(e), RNS.LOG_ERROR) self.teardown() def get_salt(self): return self.link_id def get_context(self): return None def no_inbound_for(self): """ :returns: The time in seconds since last inbound packet on the link. """ return time.time() - self.last_inbound def no_outbound_for(self): """ :returns: The time in seconds since last outbound packet on the link. """ return time.time() - self.last_outbound def inactive_for(self): """ :returns: The time in seconds since activity on the link. """ return min(self.no_inbound_for(), self.no_outbound_for()) def get_remote_identity(self): """ :returns: The identity of the remote peer, if it is known """ return self.__remote_identity def had_outbound(self): self.last_outbound = time.time() def teardown(self): """ Closes the link and purges encryption keys. New keys will be used if a new link to the same destination is established. """ if self.status != Link.PENDING and self.status != Link.CLOSED: teardown_packet = RNS.Packet(self, self.link_id, context=RNS.Packet.LINKCLOSE) teardown_packet.send() self.had_outbound() self.status = Link.CLOSED if self.initiator: self.teardown_reason = Link.INITIATOR_CLOSED else: self.teardown_reason = Link.DESTINATION_CLOSED self.link_closed() def teardown_packet(self, packet): try: plaintext = self.decrypt(packet.data) if plaintext == self.link_id: self.status = Link.CLOSED if self.initiator: self.teardown_reason = Link.DESTINATION_CLOSED else: self.teardown_reason = Link.INITIATOR_CLOSED self.link_closed() except Exception as e: pass def link_closed(self): for resource in self.incoming_resources: resource.cancel() for resource in self.outgoing_resources: resource.cancel() self.prv = None self.pub = None self.pub_bytes = None self.shared_key = None self.derived_key = None if self.callbacks.link_closed != None: self.callbacks.link_closed(self) def start_watchdog(self): thread = threading.Thread(target=self.__watchdog_job) thread.setDaemon(True) thread.start() def __watchdog_job(self): while not self.status == Link.CLOSED: while (self.watchdog_lock): sleep(max(self.rtt, 0.025)) if not self.status == Link.CLOSED: # Link was initiated, but no response # from destination yet if self.status == Link.PENDING: next_check = self.request_time + self.establishment_timeout sleep_time = next_check - time.time() if time.time() >= self.request_time + self.establishment_timeout: RNS.log("Link establishment timed out", RNS.LOG_VERBOSE) self.status = Link.CLOSED self.teardown_reason = Link.TIMEOUT self.link_closed() sleep_time = 0.001 elif self.status == Link.HANDSHAKE: next_check = self.request_time + self.establishment_timeout sleep_time = next_check - time.time() if time.time() >= self.request_time + self.establishment_timeout: if self.initiator: RNS.log("Timeout waiting link request proof", RNS.LOG_DEBUG) else: RNS.log("Timeout waiting for RTT packet from link initiator", RNS.LOG_DEBUG) self.status = Link.CLOSED self.teardown_reason = Link.TIMEOUT self.link_closed() sleep_time = 0.001 elif self.status == Link.ACTIVE: if time.time() >= self.last_inbound + self.keepalive: sleep_time = self.rtt * self.keepalive_timeout_factor + Link.STALE_GRACE self.status = Link.STALE if self.initiator: self.send_keepalive() else: sleep_time = (self.last_inbound + self.keepalive) - time.time() elif self.status == Link.STALE: sleep_time = 0.001 self.status = Link.CLOSED self.teardown_reason = Link.TIMEOUT self.link_closed() if sleep_time == 0: RNS.log("Warning! Link watchdog sleep time of 0!", RNS.LOG_ERROR) if sleep_time == None or sleep_time < 0: RNS.log("Timing error! Tearing down link "+str(self)+" now.", RNS.LOG_ERROR) self.teardown() sleep_time = 0.1 sleep(sleep_time) def send_keepalive(self): keepalive_packet = RNS.Packet(self, bytes([0xFF]), context=RNS.Packet.KEEPALIVE) keepalive_packet.send() self.had_outbound() def handle_request(self, request_id, unpacked_request): requested_at = unpacked_request[0] path_hash = unpacked_request[1] request_data = unpacked_request[2] if path_hash in self.destination.request_handlers: request_handler = self.destination.request_handlers[path_hash] path = request_handler[0] response_generator = request_handler[1] allow = request_handler[2] allowed_list = request_handler[3] allowed = False if not allow == RNS.Destination.ALLOW_NONE: if allow == RNS.Destination.ALLOW_LIST: if self.__remote_identity.hash in allowed_list: allowed = True elif allow == RNS.Destination.ALLOW_ALL: allowed = True if allowed: RNS.log("Handling request "+RNS.prettyhexrep(request_id)+" for: "+str(path), RNS.LOG_DEBUG) response = response_generator(path, request_data, request_id, self.__remote_identity, requested_at) if response != None: packed_response = umsgpack.packb([request_id, response]) if len(packed_response) <= Link.MDU: RNS.Packet(self, packed_response, RNS.Packet.DATA, context = RNS.Packet.RESPONSE).send() else: response_resource = RNS.Resource(packed_response, self, request_id = request_id, is_response = True) else: identity_string = RNS.prettyhexrep(self.get_remote_identity()) if self.get_remote_identity() != None else "" RNS.log("Request "+RNS.prettyhexrep(request_id)+" from "+identity_string+" not allowed for: "+str(path), RNS.LOG_DEBUG) def handle_response(self, request_id, response_data): remove = None for pending_request in self.pending_requests: if pending_request.request_id == request_id: remove = pending_request try: pending_request.response_received(response_data) except Exception as e: RNS.log("Error occurred while handling response. The contained exception was: "+str(e), RNS.LOG_ERROR) break if remove != None: self.pending_requests.remove(remove) def request_resource_concluded(self, resource): if resource.status == RNS.Resource.COMPLETE: packed_request = resource.data.read() unpacked_request = umsgpack.unpackb(packed_request) request_id = RNS.Identity.truncated_hash(packed_request) request_data = unpacked_request self.handle_request(request_id, request_data) else: RNS.log("Incoming request resource failed with status: "+RNS.hexrep([resource.status]), RNS.LOG_DEBUG) def response_resource_concluded(self, resource): if resource.status == RNS.Resource.COMPLETE: packed_response = resource.data.read() unpacked_response = umsgpack.unpackb(packed_response) request_id = unpacked_response[0] response_data = unpacked_response[1] self.handle_response(request_id, response_data) else: RNS.log("Incoming response resource failed with status: "+RNS.hexrep([resource.status]), RNS.LOG_DEBUG) def receive(self, packet): self.watchdog_lock = True if not self.status == Link.CLOSED and not (self.initiator and packet.context == RNS.Packet.KEEPALIVE and packet.data == bytes([0xFF])): if packet.receiving_interface != self.attached_interface: RNS.log("Link-associated packet received on unexpected interface! Someone might be trying to manipulate your communication!", RNS.LOG_ERROR) else: self.last_inbound = time.time() self.rx += 1 self.rxbytes += len(packet.data) if self.status == Link.STALE: self.status = Link.ACTIVE if packet.packet_type == RNS.Packet.DATA: if packet.context == RNS.Packet.NONE: plaintext = self.decrypt(packet.data) if self.callbacks.packet != None: thread = threading.Thread(target=self.callbacks.packet, args=(plaintext, packet)) thread.setDaemon(True) thread.start() if self.destination.proof_strategy == RNS.Destination.PROVE_ALL: packet.prove() elif self.destination.proof_strategy == RNS.Destination.PROVE_APP: if self.destination.callbacks.proof_requested: self.destination.callbacks.proof_requested(packet) elif packet.context == RNS.Packet.LINKIDENTIFY: plaintext = self.decrypt(packet.data) if not self.initiator and len(plaintext) == RNS.Identity.KEYSIZE//8 + RNS.Identity.SIGLENGTH//8: public_key = plaintext[:RNS.Identity.KEYSIZE//8] signed_data = self.link_id+public_key signature = plaintext[RNS.Identity.KEYSIZE//8:RNS.Identity.KEYSIZE//8+RNS.Identity.SIGLENGTH//8] identity = RNS.Identity(create_keys=False) identity.load_public_key(public_key) if identity.validate(signature, signed_data): self.__remote_identity = identity if self.callbacks.remote_identified != None: self.callbacks.remote_identified(self.__remote_identity) elif packet.context == RNS.Packet.REQUEST: try: request_id = packet.getTruncatedHash() packed_request = self.decrypt(packet.data) unpacked_request = umsgpack.unpackb(packed_request) self.handle_request(request_id, unpacked_request) except Exception as e: RNS.log("Error occurred while handling request. The contained exception was: "+str(e), RNS.LOG_ERROR) elif packet.context == RNS.Packet.RESPONSE: try: packed_response = self.decrypt(packet.data) unpacked_response = umsgpack.unpackb(packed_response) request_id = unpacked_response[0] response_data = unpacked_response[1] self.handle_response(request_id, response_data) except Exception as e: RNS.log("Error occurred while handling response. The contained exception was: "+str(e), RNS.LOG_ERROR) elif packet.context == RNS.Packet.LRRTT: if not self.initiator: self.rtt_packet(packet) elif packet.context == RNS.Packet.LINKCLOSE: self.teardown_packet(packet) elif packet.context == RNS.Packet.RESOURCE_ADV: packet.plaintext = self.decrypt(packet.data) if RNS.ResourceAdvertisement.is_request(packet): RNS.Resource.accept(packet, callback=self.request_resource_concluded) elif RNS.ResourceAdvertisement.is_response(packet): request_id = RNS.ResourceAdvertisement.get_request_id(packet) for pending_request in self.pending_requests: if pending_request.request_id == request_id: RNS.Resource.accept(packet, callback=self.response_resource_concluded, progress_callback=pending_request.response_resource_progress) pending_request.response_size = RNS.ResourceAdvertisement.get_size(packet) pending_request.response_transfer_size = RNS.ResourceAdvertisement.get_transfer_size(packet) pending_request.started_at = time.time() elif self.resource_strategy == Link.ACCEPT_NONE: pass elif self.resource_strategy == Link.ACCEPT_APP: if self.callbacks.resource != None: if self.callbacks.resource(resource): RNS.Resource.accept(packet, self.callbacks.resource_concluded) elif self.resource_strategy == Link.ACCEPT_ALL: RNS.Resource.accept(packet, self.callbacks.resource_concluded) elif packet.context == RNS.Packet.RESOURCE_REQ: plaintext = self.decrypt(packet.data) if ord(plaintext[:1]) == RNS.Resource.HASHMAP_IS_EXHAUSTED: resource_hash = plaintext[1+RNS.Resource.MAPHASH_LEN:RNS.Identity.HASHLENGTH//8+1+RNS.Resource.MAPHASH_LEN] else: resource_hash = plaintext[1:RNS.Identity.HASHLENGTH//8+1] for resource in self.outgoing_resources: if resource.hash == resource_hash: # We need to check that this request has not been # received before in order to avoid sequencing errors. if not packet.packet_hash in resource.req_hashlist: resource.req_hashlist.append(packet.packet_hash) resource.request(plaintext) elif packet.context == RNS.Packet.RESOURCE_HMU: plaintext = self.decrypt(packet.data) resource_hash = plaintext[:RNS.Identity.HASHLENGTH//8] for resource in self.incoming_resources: if resource_hash == resource.hash: resource.hashmap_update_packet(plaintext) elif packet.context == RNS.Packet.RESOURCE_ICL: plaintext = self.decrypt(packet.data) resource_hash = plaintext[:RNS.Identity.HASHLENGTH//8] for resource in self.incoming_resources: if resource_hash == resource.hash: resource.cancel() elif packet.context == RNS.Packet.KEEPALIVE: if not self.initiator and packet.data == bytes([0xFF]): keepalive_packet = RNS.Packet(self, bytes([0xFE]), context=RNS.Packet.KEEPALIVE) keepalive_packet.send() self.had_outbound() # TODO: find the most efficient way to allow multiple # transfers at the same time, sending resource hash on # each packet is a huge overhead. Probably some kind # of hash -> sequence map elif packet.context == RNS.Packet.RESOURCE: for resource in self.incoming_resources: resource.receive_part(packet) elif packet.packet_type == RNS.Packet.PROOF: if packet.context == RNS.Packet.RESOURCE_PRF: resource_hash = packet.data[0:RNS.Identity.HASHLENGTH//8] for resource in self.outgoing_resources: if resource_hash == resource.hash: resource.validate_proof(packet.data) self.watchdog_lock = False def encrypt(self, plaintext): try: if not self.fernet: try: self.fernet = Fernet(base64.urlsafe_b64encode(self.derived_key)) except Exception as e: RNS.log("Could not "+str(self)+" instantiate Fernet while performin encryption on link. The contained exception was: "+str(e), RNS.LOG_ERROR) raise e # The fernet token VERSION field is stripped here and # reinserted on the receiving end, since it is always # set to 0x80. # # Since we're also quite content with supporting time- # stamps until the year 8921556 AD, we'll also strip 2 # bytes from the timestamp field and reinsert those as # 0x00 when received. ciphertext = base64.urlsafe_b64decode(self.fernet.encrypt(plaintext))[3:] return ciphertext except Exception as e: RNS.log("Encryption on link "+str(self)+" failed. The contained exception was: "+str(e), RNS.LOG_ERROR) raise e def decrypt(self, ciphertext): try: if not self.fernet: self.fernet = Fernet(base64.urlsafe_b64encode(self.derived_key)) plaintext = self.fernet.decrypt(base64.urlsafe_b64encode(bytes([RNS.Identity.FERNET_VERSION, 0x00, 0x00])+ciphertext)) return plaintext except Exception as e: RNS.log("Decryption failed on link "+str(self)+". The contained exception was: "+str(e), RNS.LOG_ERROR) RNS.log(traceback.format_exc(), RNS.LOG_ERROR) # TODO: Think long about implications here # self.teardown() def sign(self, message): return self.sig_prv.sign(message) def validate(self, signature, message): try: self.peer_sig_pub.verify(signature, message) return True except Exception as e: return False def set_link_established_callback(self, callback): self.callbacks.link_established = callback def set_link_closed_callback(self, callback): self.callbacks.link_closed = callback def set_packet_callback(self, callback): """ Registers a function to be called when a packet has been received over this link. :param callback: A function or method with the signature *callback(message, packet)* to be called. """ self.callbacks.packet = callback def set_resource_callback(self, callback): """ Registers a function to be called when a resource has been advertised over this link. If the function returns *True* the resource will be accepted. If it returns *False* it will be ignored. :param callback: A function or method with the signature *callback(resource)* to be called. """ self.callbacks.resource = callback def set_resource_started_callback(self, callback): """ Registers a function to be called when a resource has begun transferring over this link. :param callback: A function or method with the signature *callback(resource)* to be called. """ self.callbacks.resource_started = callback def set_resource_concluded_callback(self, callback): """ Registers a function to be called when a resource has concluded transferring over this link. :param callback: A function or method with the signature *callback(resource)* to be called. """ self.callbacks.resource_concluded = callback def set_remote_identified_callback(self, callback): """ Registers a function to be called when an initiating peer has identified over this link. :param callback: A function or method with the signature *callback(identity)* to be called. """ self.callbacks.remote_identified = callback def resource_concluded(self, resource): if resource in self.incoming_resources: self.incoming_resources.remove(resource) if resource in self.outgoing_resources: self.outgoing_resources.remove(resource) def set_resource_strategy(self, resource_strategy): """ Sets the resource strategy for the link. :param resource_strategy: One of ``RNS.Link.ACCEPT_NONE``, ``RNS.Link.ACCEPT_ALL`` or ``RNS.Link.ACCEPT_APP``. If ``RNS.Link.ACCEPT_APP`` is set, the `resource_callback` will be called to determine whether the resource should be accepted or not. :raises: *TypeError* if the resource strategy is unsupported. """ if not resource_strategy in Link.resource_strategies: raise TypeError("Unsupported resource strategy") else: self.resource_strategy = resource_strategy def register_outgoing_resource(self, resource): self.outgoing_resources.append(resource) def register_incoming_resource(self, resource): self.incoming_resources.append(resource) def cancel_outgoing_resource(self, resource): if resource in self.outgoing_resources: self.outgoing_resources.remove(resource) else: RNS.log("Attempt to cancel a non-existing outgoing resource", RNS.LOG_ERROR) def cancel_incoming_resource(self, resource): if resource in self.incoming_resources: self.incoming_resources.remove(resource) else: RNS.log("Attempt to cancel a non-existing incoming resource", RNS.LOG_ERROR) def ready_for_new_resource(self): if len(self.outgoing_resources) > 0: return False else: return True def __str__(self): return RNS.prettyhexrep(self.link_id) class RequestReceipt(): """ An instance of this class is returned by the ``request`` method of ``RNS.Link`` instances. It should never be instantiated manually. It provides methods to check status, response time and response data when the request concludes. """ FAILED = 0x00 SENT = 0x01 DELIVERED = 0x02 READY = 0x03 def __init__(self, link, packet_receipt = None, resource = None, response_callback = None, failed_callback = None, progress_callback = None, timeout = None): self.packet_receipt = packet_receipt self.resource = resource self.started_at = None if self.packet_receipt != None: self.hash = packet_receipt.truncated_hash self.packet_receipt.set_timeout_callback(self.request_timed_out) self.started_at = time.time() elif self.resource != None: self.hash = resource.request_id resource.set_callback(self.request_resource_concluded) self.link = link self.request_id = self.hash self.response = None self.response_transfer_size = None self.response_size = None self.status = RequestReceipt.SENT self.sent_at = time.time() self.progress = 0 self.concluded_at = None self.response_concluded_at = None if timeout != None: self.timeout = timeout else: raise ValueError("No timeout specified for request receipt") self.callbacks = RequestReceiptCallbacks() self.callbacks.response = response_callback self.callbacks.failed = failed_callback self.callbacks.progress = progress_callback self.link.pending_requests.append(self) def request_resource_concluded(self, resource): if resource.status == RNS.Resource.COMPLETE: RNS.log("Request "+RNS.prettyhexrep(self.request_id)+" successfully sent as resource.", RNS.LOG_DEBUG) self.started_at = time.time() self.status = RequestReceipt.DELIVERED self.__resource_response_timeout = time.time()+self.timeout load_thread = threading.Thread(target=self.__resource_response_timeout_job) load_thread.setDaemon(True) load_thread.start() else: RNS.log("Sending request "+RNS.prettyhexrep(self.request_id)+" as resource failed with status: "+RNS.hexrep([resource.status]), RNS.LOG_DEBUG) self.status = RequestReceipt.FAILED self.concluded_at = time.time() self.link.pending_requests.remove(self) if self.callbacks.failed != None: self.callbacks.failed(self) def request_timed_out(self, packet_receipt): self.status = RequestReceipt.FAILED self.concluded_at = time.time() self.link.pending_requests.remove(self) if self.callbacks.failed != None: self.callbacks.failed(self) def response_resource_progress(self, resource): if not self.status == RequestReceipt.FAILED: self.status = RequestReceipt.DELIVERED if self.packet_receipt != None: self.packet_receipt.status = RNS.PacketReceipt.DELIVERED self.packet_receipt.proved = True self.packet_receipt.concluded_at = time.time() if self.packet_receipt.callbacks.delivery != None: self.packet_receipt.callbacks.delivery(self.packet_receipt) self.progress = resource.get_progress() now = time.time() self.__resource_response_timeout = time.time()+self.timeout if self.callbacks.progress != None: self.callbacks.progress(self) else: resource.cancel() def __resource_response_timeout_job(self): while self.status == RequestReceipt.DELIVERED: now = time.time() if now > self.__resource_response_timeout: self.request_timed_out(None) time.sleep(0.1) def response_received(self, response): if not self.status == RequestReceipt.FAILED: self.progress = 1.0 self.response = response self.status = RequestReceipt.READY self.response_concluded_at = time.time() if len(response) <= Link.MDU: self.response_size = len(response) self.response_transfer_size = len(response) if self.packet_receipt != None: self.packet_receipt.status = RNS.PacketReceipt.DELIVERED self.packet_receipt.proved = True self.packet_receipt.concluded_at = time.time() if self.packet_receipt.callbacks.delivery != None: self.packet_receipt.callbacks.delivery(self.packet_receipt) if self.callbacks.progress != None: self.callbacks.progress(self) if self.callbacks.response != None: self.callbacks.response(self) def get_request_id(self): """ :returns: The request ID as *bytes*. """ return self.request_id def get_status(self): """ :returns: The current status of the request, one of ``RNS.RequestReceipt.FAILED``, ``RNS.RequestReceipt.SENT``, ``RNS.RequestReceipt.DELIVERED``, ``RNS.RequestReceipt.READY``. """ return self.status def get_progress(self): """ :returns: The progress of a response being received as a *float* between 0.0 and 1.0. """ return self.progress def get_response(self): """ :returns: The response as *bytes* if it is ready, otherwise *None*. """ if self.status == RequestReceipt.READY: return self.response else: return None def get_response_time(self): """ :returns: The response time of the request in seconds. """ if self.status == RequestReceipt.READY: return self.response_concluded_at - self.started_at else: return None class RequestReceiptCallbacks: def __init__(self): self.response = None self.failed = None self.progress = None