# MIT License # # Copyright (c) 2016-2023 Mark Qvist / unsigned.io and contributors. # # Permission is hereby granted, free of charge, to any person obtaining a copy # of this software and associated documentation files (the "Software"), to deal # in the Software without restriction, including without limitation the rights # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell # copies of the Software, and to permit persons to whom the Software is # furnished to do so, subject to the following conditions: # # The above copyright notice and this permission notice shall be included in all # copies or substantial portions of the Software. # # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE # SOFTWARE. from RNS.Cryptography import X25519PrivateKey, X25519PublicKey, Ed25519PrivateKey, Ed25519PublicKey from RNS.Cryptography import Fernet from RNS.Channel import Channel, LinkChannelOutlet from time import sleep from .vendor import umsgpack as umsgpack import threading import inspect import math import time import RNS 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 and encrypted 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.IFAC_MIN_SIZE-RNS.Reticulum.HEADER_MINSIZE-RNS.Identity.FERNET_OVERHEAD)/RNS.Identity.AES128_BLOCKSIZE)*RNS.Identity.AES128_BLOCKSIZE - 1 ESTABLISHMENT_TIMEOUT_PER_HOP = RNS.Reticulum.DEFAULT_PER_HOP_TIMEOUT """ Timeout for link establishment in seconds per hop to destination. """ TRAFFIC_TIMEOUT_FACTOR = 6 KEEPALIVE_TIMEOUT_FACTOR = 4 """ RTT timeout factor used in link timeout calculation. """ STALE_GRACE = 2 """ Grace period in seconds used in link timeout calculation. """ KEEPALIVE = 360 """ Interval for sending keep-alive packets on established links in seconds. """ STALE_TIME = 2*KEEPALIVE """ If no traffic or keep-alive packets are received within this period, the link will be marked as stale, and a final keep-alive packet will be sent. If after this no traffic or keep-alive packets are received within ``RTT`` * ``KEEPALIVE_TIMEOUT_FACTOR`` + ``STALE_GRACE``, the link is considered timed out, and will be torn down. """ 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) + Link.KEEPALIVE link.establishment_cost += len(packet.raw) RNS.log("Validating link request "+RNS.prettyhexrep(link.link_id), RNS.LOG_VERBOSE) RNS.log(f"Establishment timeout is {RNS.prettytime(link.establishment_timeout)} for incoming link request "+RNS.prettyhexrep(link.link_id), RNS.LOG_EXTREME) 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_DEBUG) return link except Exception as e: RNS.log("Validating link request failed", RNS.LOG_VERBOSE) RNS.log("exc: "+str(e)) return None else: RNS.log("Invalid link request payload size, dropping request", RNS.LOG_DEBUG) 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.establishment_cost = 0 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.last_proof = 0 self.last_data = 0 self.tx = 0 self.rx = 0 self.txbytes = 0 self.rxbytes = 0 self.rssi = None self.snr = None self.q = None self.traffic_timeout_factor = Link.TRAFFIC_TIMEOUT_FACTOR self.keepalive_timeout_factor = Link.KEEPALIVE_TIMEOUT_FACTOR self.keepalive = Link.KEEPALIVE self.stale_time = Link.STALE_TIME self.watchdog_lock = False self.status = Link.PENDING self.activated_at = None self.type = RNS.Destination.LINK self.owner = owner self.destination = destination self.expected_hops = None self.attached_interface = None self.__remote_identity = None self.__track_phy_stats = False self._channel = None if self.destination == None: self.initiator = False self.prv = X25519PrivateKey.generate() self.sig_prv = self.owner.identity.sig_prv else: self.initiator = True self.expected_hops = RNS.Transport.hops_to(self.destination.hash) self.establishment_timeout = RNS.Reticulum.get_instance().get_first_hop_timeout(destination.hash) 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() self.sig_pub = self.sig_prv.public_key() self.sig_pub_bytes = self.sig_pub.public_bytes() 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): 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.establishment_cost += len(self.packet.raw) self.set_link_id(self.packet) 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_DEBUG) RNS.log(f"Establishment timeout is {RNS.prettytime(self.establishment_timeout)} for link request "+RNS.prettyhexrep(self.link_id), RNS.LOG_EXTREME) 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): if self.status == Link.PENDING and self.prv != None: self.status = Link.HANDSHAKE self.shared_key = self.prv.exchange(self.peer_pub) self.derived_key = RNS.Cryptography.hkdf( length=32, derive_from=self.shared_key, salt=self.get_salt(), context=self.get_context(), ) else: RNS.log("Handshake attempt on "+str(self)+" with invalid state "+str(self.status), RNS.LOG_ERROR) 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+self.pub_bytes proof = RNS.Packet(self, proof_data, packet_type=RNS.Packet.PROOF, context=RNS.Packet.LRPROOF) proof.send() self.establishment_cost += len(proof.raw) 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): try: if self.status == Link.PENDING: if self.initiator and len(packet.data) == RNS.Identity.SIGLENGTH//8+Link.ECPUBSIZE//2: peer_pub_bytes = packet.data[RNS.Identity.SIGLENGTH//8:RNS.Identity.SIGLENGTH//8+Link.ECPUBSIZE//2] peer_sig_pub_bytes = self.destination.identity.get_public_key()[Link.ECPUBSIZE//2:Link.ECPUBSIZE] self.load_peer(peer_pub_bytes, peer_sig_pub_bytes) self.handshake() self.establishment_cost += len(packet.raw) 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): if self.status != Link.HANDSHAKE: raise IOError("Invalid link state for proof validation: "+str(self.status)) self.rtt = time.time() - self.request_time self.attached_interface = packet.receiving_interface self.__remote_identity = self.destination.identity self.status = Link.ACTIVE self.activated_at = time.time() self.last_proof = self.activated_at RNS.Transport.activate_link(self) RNS.log("Link "+str(self)+" established with "+str(self.destination)+", RTT is "+str(round(self.rtt, 3))+"s", RNS.LOG_VERBOSE) if self.rtt != None and self.establishment_cost != None and self.rtt > 0 and self.establishment_cost > 0: self.establishment_rate = self.establishment_cost/self.rtt rtt_data = umsgpack.packb(self.rtt) rtt_packet = RNS.Packet(self, rtt_data, context=RNS.Packet.LRRTT) rtt_packet.send() self.had_outbound() if self.callbacks.link_established != None: thread = threading.Thread(target=self.callbacks.link_established, args=(self,)) thread.daemon = True thread.start() else: RNS.log("Invalid link proof signature received by "+str(self)+". Ignoring.", RNS.LOG_DEBUG) except Exception as e: self.status = Link.CLOSED RNS.log("An error ocurred while validating link request proof on "+str(self)+".", RNS.LOG_ERROR) RNS.log("The contained exception was: "+str(e), RNS.LOG_ERROR) 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 and self.status == Link.ACTIVE: 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 + RNS.Resource.RESPONSE_MAX_GRACE_TIME*1.125 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, request_size = len(packed_request), ) 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, request_size = len(packed_request), ) def rtt_packet(self, packet): try: measured_rtt = time.time() - self.request_time plaintext = self.decrypt(packet.data) if plaintext != None: rtt = umsgpack.unpackb(plaintext) self.rtt = max(measured_rtt, rtt) self.status = Link.ACTIVE self.activated_at = time.time() if self.rtt != None and self.establishment_cost != None and self.rtt > 0 and self.establishment_cost > 0: self.establishment_rate = self.establishment_cost/self.rtt try: if self.owner.callbacks.link_established != None: self.owner.callbacks.link_established(self) except Exception as e: RNS.log("Error occurred in external link establishment callback. The contained exception was: "+str(e), RNS.LOG_ERROR) 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 track_phy_stats(self, track): """ You can enable physical layer statistics on a per-link basis. If this is enabled, and the link is running over an interface that supports reporting physical layer statistics, you will be able to retrieve stats such as *RSSI*, *SNR* and physical *Link Quality* for the link. :param track: Whether or not to keep track of physical layer statistics. Value must be ``True`` or ``False``. """ if track: self.__track_phy_stats = True else: self.__track_phy_stats = False def get_rssi(self): """ :returns: The physical layer *Received Signal Strength Indication* if available, otherwise ``None``. Physical layer statistics must be enabled on the link for this method to return a value. """ return self.rssi def get_snr(self): """ :returns: The physical layer *Signal-to-Noise Ratio* if available, otherwise ``None``. Physical layer statistics must be enabled on the link for this method to return a value. """ return self.rssi def get_q(self): """ :returns: The physical layer *Link Quality* if available, otherwise ``None``. Physical layer statistics must be enabled on the link for this method to return a value. """ return self.rssi def get_establishment_rate(self): """ :returns: The data transfer rate at which the link establishment procedure ocurred, in bits per second. """ if self.establishment_rate != None: return self.establishment_rate*8 else: return None 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. This includes keepalive packets. """ activated_at = self.activated_at if self.activated_at != None else 0 last_inbound = max(self.last_inbound, activated_at) return time.time() - last_inbound def no_outbound_for(self): """ :returns: The time in seconds since last outbound packet on the link. This includes keepalive packets. """ return time.time() - self.last_outbound def no_data_for(self): """ :returns: The time in seconds since payload data traversed the link. This excludes keepalive packets. """ return time.time() - self.last_data def inactive_for(self): """ :returns: The time in seconds since activity on the link. This includes keepalive packets. """ 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. Calling this method will not query the remote initiator to reveal its identity. Returns ``None`` if the link initiator has not already independently called the ``identify(identity)`` method. """ return self.__remote_identity def had_outbound(self, is_keepalive=False): self.last_outbound = time.time() if not is_keepalive: self.last_data = self.last_outbound 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.__update_phy_stats(packet) 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() if self._channel: self._channel._shutdown() self.prv = None self.pub = None self.pub_bytes = None self.shared_key = None self.derived_key = None if self.destination != None: if self.destination.direction == RNS.Destination.IN: if self in self.destination.links: self.destination.links.remove(self) if self.callbacks.link_closed != None: try: self.callbacks.link_closed(self) except Exception as e: RNS.log("Error while executing link closed callback from "+str(self)+". The contained exception was: "+str(e), RNS.LOG_ERROR) def start_watchdog(self): thread = threading.Thread(target=self.__watchdog_job) thread.daemon = True thread.start() def __watchdog_job(self): while not self.status == Link.CLOSED: while (self.watchdog_lock): rtt_wait = 0.025 if hasattr(self, "rtt") and self.rtt: rtt_wait = self.rtt sleep(max(rtt_wait, 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: self.status = Link.CLOSED self.teardown_reason = Link.TIMEOUT self.link_closed() sleep_time = 0.001 if self.initiator: RNS.log("Timeout waiting for link request proof", RNS.LOG_DEBUG) else: RNS.log("Timeout waiting for RTT packet from link initiator", RNS.LOG_DEBUG) elif self.status == Link.ACTIVE: activated_at = self.activated_at if self.activated_at != None else 0 last_inbound = max(max(self.last_inbound, self.last_proof), activated_at) if time.time() >= last_inbound + self.keepalive: if self.initiator: self.send_keepalive() if time.time() >= last_inbound + self.stale_time: sleep_time = self.rtt * self.keepalive_timeout_factor + Link.STALE_GRACE self.status = Link.STALE else: sleep_time = self.keepalive else: sleep_time = (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 __update_phy_stats(self, packet, query_shared = True): if self.__track_phy_stats: if query_shared: reticulum = RNS.Reticulum.get_instance() if packet.rssi == None: packet.rssi = reticulum.get_packet_rssi(packet.packet_hash) if packet.snr == None: packet.snr = reticulum.get_packet_snr(packet.packet_hash) if packet.q == None: packet.q = reticulum.get_packet_q(packet.packet_hash) if packet.rssi != None: self.rssi = packet.rssi if packet.snr != None: self.snr = packet.snr if packet.q != None: self.q = packet.q def send_keepalive(self): keepalive_packet = RNS.Packet(self, bytes([0xFF]), context=RNS.Packet.KEEPALIVE) keepalive_packet.send() self.had_outbound(is_keepalive = True) def handle_request(self, request_id, unpacked_request): if self.status == Link.ACTIVE: 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 != None and 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) if len(inspect.signature(response_generator).parameters) == 5: response = response_generator(path, request_data, request_id, self.__remote_identity, requested_at) elif len(inspect.signature(response_generator).parameters) == 6: response = response_generator(path, request_data, request_id, self.link_id, self.__remote_identity, requested_at) else: raise TypeError("Invalid signature for response generator callback") 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 = str(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, response_size, response_transfer_size): if self.status == Link.ACTIVE: remove = None for pending_request in self.pending_requests: if pending_request.request_id == request_id: remove = pending_request try: pending_request.response_size = response_size if pending_request.response_transfer_size == None: pending_request.response_transfer_size = 0 pending_request.response_transfer_size += response_transfer_size 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: if remove in self.pending_requests: 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, resource.total_size, resource.size) else: RNS.log("Incoming response resource failed with status: "+RNS.hexrep([resource.status]), RNS.LOG_DEBUG) for pending_request in self.pending_requests: if pending_request.request_id == resource.request_id: pending_request.request_timed_out(None) def get_channel(self): """ Get the ``Channel`` for this link. :return: ``Channel`` object """ if self._channel is None: self._channel = Channel(LinkChannelOutlet(self)) return self._channel 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() if packet.context != RNS.Packet.KEEPALIVE: self.last_data = self.last_inbound self.rx += 1 self.rxbytes += len(packet.data) if self.status == Link.STALE: self.status = Link.ACTIVE if packet.packet_type == RNS.Packet.DATA: should_query = False if packet.context == RNS.Packet.NONE: plaintext = self.decrypt(packet.data) if plaintext != None: if self.callbacks.packet != None: thread = threading.Thread(target=self.callbacks.packet, args=(plaintext, packet)) thread.daemon = True thread.start() if self.destination.proof_strategy == RNS.Destination.PROVE_ALL: packet.prove() should_query = True elif self.destination.proof_strategy == RNS.Destination.PROVE_APP: if self.destination.callbacks.proof_requested: try: if self.destination.callbacks.proof_requested(packet): packet.prove() should_query = True except Exception as e: RNS.log("Error while executing proof request callback from "+str(self)+". The contained exception was: "+str(e), RNS.LOG_ERROR) self.__update_phy_stats(packet, query_shared=should_query) elif packet.context == RNS.Packet.LINKIDENTIFY: plaintext = self.decrypt(packet.data) if plaintext != None: 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: try: self.callbacks.remote_identified(self, self.__remote_identity) except Exception as e: RNS.log("Error while executing remote identified callback from "+str(self)+". The contained exception was: "+str(e), RNS.LOG_ERROR) self.__update_phy_stats(packet, query_shared=True) elif packet.context == RNS.Packet.REQUEST: try: request_id = packet.getTruncatedHash() packed_request = self.decrypt(packet.data) if packed_request != None: unpacked_request = umsgpack.unpackb(packed_request) self.handle_request(request_id, unpacked_request) self.__update_phy_stats(packet, query_shared=True) 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) if packed_response != None: unpacked_response = umsgpack.unpackb(packed_response) request_id = unpacked_response[0] response_data = unpacked_response[1] transfer_size = len(umsgpack.packb(response_data))-2 self.handle_response(request_id, response_data, transfer_size, transfer_size) self.__update_phy_stats(packet, query_shared=True) 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) self.__update_phy_stats(packet, query_shared=True) elif packet.context == RNS.Packet.LINKCLOSE: self.teardown_packet(packet) self.__update_phy_stats(packet, query_shared=True) elif packet.context == RNS.Packet.RESOURCE_ADV: packet.plaintext = self.decrypt(packet.data) if packet.plaintext != None: self.__update_phy_stats(packet, query_shared=True) 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.read_request_id(packet) for pending_request in self.pending_requests: if pending_request.request_id == request_id: response_resource = RNS.Resource.accept(packet, callback=self.response_resource_concluded, progress_callback=pending_request.response_resource_progress, request_id = request_id) if response_resource != None: if pending_request.response_size == None: pending_request.response_size = RNS.ResourceAdvertisement.read_size(packet) if pending_request.response_transfer_size == None: pending_request.response_transfer_size = 0 pending_request.response_transfer_size += RNS.ResourceAdvertisement.read_transfer_size(packet) if pending_request.started_at == None: pending_request.started_at = time.time() pending_request.response_resource_progress(response_resource) elif self.resource_strategy == Link.ACCEPT_NONE: pass elif self.resource_strategy == Link.ACCEPT_APP: if self.callbacks.resource != None: try: resource_advertisement = RNS.ResourceAdvertisement.unpack(packet.plaintext) resource_advertisement.link = self if self.callbacks.resource(resource_advertisement): RNS.Resource.accept(packet, self.callbacks.resource_concluded) except Exception as e: RNS.log("Error while executing resource accept callback from "+str(self)+". The contained exception was: "+str(e), RNS.LOG_ERROR) 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 plaintext != None: self.__update_phy_stats(packet, query_shared=True) 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) if plaintext != None: self.__update_phy_stats(packet, query_shared=True) 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) if plaintext != None: self.__update_phy_stats(packet) 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(is_keepalive = True) # 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) self.__update_phy_stats(packet) elif packet.context == RNS.Packet.CHANNEL: if not self._channel: RNS.log(f"Channel data received without open channel", RNS.LOG_DEBUG) else: packet.prove() plaintext = self.decrypt(packet.data) if plaintext != None: self.__update_phy_stats(packet) self._channel._receive(plaintext) 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.__update_phy_stats(packet, query_shared=True) self.watchdog_lock = False def encrypt(self, plaintext): try: if not self.fernet: try: self.fernet = Fernet(self.derived_key) except Exception as e: RNS.log("Could not instantiate Fernet while performin encryption on link "+str(self)+". The contained exception was: "+str(e), RNS.LOG_ERROR) raise e return self.fernet.encrypt(plaintext) 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(self.derived_key) return self.fernet.decrypt(ciphertext) except Exception as e: RNS.log("Decryption failed on link "+str(self)+". The contained exception was: "+str(e), RNS.LOG_ERROR) return None 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): """ Registers a function to be called when a link has been torn down. :param callback: A function or method with the signature *callback(link)* to be called. """ 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. Please note that only the basic information of the resource is available at this time, such as *get_transfer_size()*, *get_data_size()*, *get_parts()* and *is_compressed()*. """ 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(link, 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 has_incoming_resource(self, resource): for incoming_resource in self.incoming_resources: if incoming_resource.hash == resource.hash: return True return False 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 RECEIVING = 0x03 READY = 0x04 def __init__(self, link, packet_receipt = None, resource = None, response_callback = None, failed_callback = None, progress_callback = None, timeout = None, request_size = 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.request_size = request_size 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) if self.started_at == None: self.started_at = time.time() self.status = RequestReceipt.DELIVERED self.__resource_response_timeout = time.time()+self.timeout response_timeout_thread = threading.Thread(target=self.__response_timeout_job) response_timeout_thread.daemon = True response_timeout_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: try: self.callbacks.failed(self) except Exception as e: RNS.log("Error while executing request failed callback from "+str(self)+". The contained exception was: "+str(e), RNS.LOG_ERROR) def __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 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: try: self.callbacks.failed(self) except Exception as e: RNS.log("Error while executing request timed out callback from "+str(self)+". The contained exception was: "+str(e), RNS.LOG_ERROR) def response_resource_progress(self, resource): if resource != None: if not self.status == RequestReceipt.FAILED: self.status = RequestReceipt.RECEIVING if self.packet_receipt != None: if self.packet_receipt.status != RNS.PacketReceipt.DELIVERED: 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() if self.callbacks.progress != None: try: self.callbacks.progress(self) except Exception as e: RNS.log("Error while executing response progress callback from "+str(self)+". The contained exception was: "+str(e), RNS.LOG_ERROR) else: resource.cancel() 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 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: try: self.callbacks.progress(self) except Exception as e: RNS.log("Error while executing response progress callback from "+str(self)+". The contained exception was: "+str(e), RNS.LOG_ERROR) if self.callbacks.response != None: try: self.callbacks.response(self) except Exception as e: RNS.log("Error while executing response received callback from "+str(self)+". The contained exception was: "+str(e), RNS.LOG_ERROR) 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