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540 lines
22 KiB
540 lines
22 KiB
# MIT License
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#
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# Copyright (c) 2016-2023 Mark Qvist / unsigned.io and contributors.
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in all
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# copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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# SOFTWARE.
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import threading
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import struct
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import math
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import time
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import RNS
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class Packet:
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"""
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The Packet class is used to create packet instances that can be sent
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over a Reticulum network. Packets will automatically be encrypted if
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they are addressed to a ``RNS.Destination.SINGLE`` destination,
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``RNS.Destination.GROUP`` destination or a :ref:`RNS.Link<api-link>`.
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For ``RNS.Destination.GROUP`` destinations, Reticulum will use the
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pre-shared key configured for the destination. All packets to group
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destinations are encrypted with the same AES-128 key.
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For ``RNS.Destination.SINGLE`` destinations, Reticulum will use a newly
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derived ephemeral AES-128 key for every packet.
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For :ref:`RNS.Link<api-link>` destinations, Reticulum will use per-link
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ephemeral keys, and offers **Forward Secrecy**.
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:param destination: A :ref:`RNS.Destination<api-destination>` instance to which the packet will be sent.
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:param data: The data payload to be included in the packet as *bytes*.
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:param create_receipt: Specifies whether a :ref:`RNS.PacketReceipt<api-packetreceipt>` should be created when instantiating the packet.
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"""
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# Packet types
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DATA = 0x00 # Data packets
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ANNOUNCE = 0x01 # Announces
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LINKREQUEST = 0x02 # Link requests
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PROOF = 0x03 # Proofs
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types = [DATA, ANNOUNCE, LINKREQUEST, PROOF]
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# Header types
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HEADER_1 = 0x00 # Normal header format
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HEADER_2 = 0x01 # Header format used for packets in transport
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header_types = [HEADER_1, HEADER_2]
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# Packet context types
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NONE = 0x00 # Generic data packet
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RESOURCE = 0x01 # Packet is part of a resource
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RESOURCE_ADV = 0x02 # Packet is a resource advertisement
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RESOURCE_REQ = 0x03 # Packet is a resource part request
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RESOURCE_HMU = 0x04 # Packet is a resource hashmap update
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RESOURCE_PRF = 0x05 # Packet is a resource proof
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RESOURCE_ICL = 0x06 # Packet is a resource initiator cancel message
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RESOURCE_RCL = 0x07 # Packet is a resource receiver cancel message
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CACHE_REQUEST = 0x08 # Packet is a cache request
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REQUEST = 0x09 # Packet is a request
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RESPONSE = 0x0A # Packet is a response to a request
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PATH_RESPONSE = 0x0B # Packet is a response to a path request
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COMMAND = 0x0C # Packet is a command
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COMMAND_STATUS = 0x0D # Packet is a status of an executed command
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CHANNEL = 0x0E # Packet contains link channel data
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KEEPALIVE = 0xFA # Packet is a keepalive packet
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LINKIDENTIFY = 0xFB # Packet is a link peer identification proof
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LINKCLOSE = 0xFC # Packet is a link close message
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LINKPROOF = 0xFD # Packet is a link packet proof
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LRRTT = 0xFE # Packet is a link request round-trip time measurement
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LRPROOF = 0xFF # Packet is a link request proof
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# This is used to calculate allowable
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# payload sizes
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HEADER_MAXSIZE = RNS.Reticulum.HEADER_MAXSIZE
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MDU = RNS.Reticulum.MDU
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# With an MTU of 500, the maximum of data we can
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# send in a single encrypted packet is given by
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# the below calculation; 383 bytes.
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ENCRYPTED_MDU = math.floor((RNS.Reticulum.MDU-RNS.Identity.FERNET_OVERHEAD-RNS.Identity.KEYSIZE//16)/RNS.Identity.AES128_BLOCKSIZE)*RNS.Identity.AES128_BLOCKSIZE - 1
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"""
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The maximum size of the payload data in a single encrypted packet
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"""
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PLAIN_MDU = MDU
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"""
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The maximum size of the payload data in a single unencrypted packet
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"""
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TIMEOUT_PER_HOP = RNS.Reticulum.DEFAULT_PER_HOP_TIMEOUT
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def __init__(self, destination, data, packet_type = DATA, context = NONE, transport_type = RNS.Transport.BROADCAST, header_type = HEADER_1, transport_id = None, attached_interface = None, create_receipt = True):
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if destination != None:
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if transport_type == None:
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transport_type = RNS.Transport.BROADCAST
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self.header_type = header_type
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self.packet_type = packet_type
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self.transport_type = transport_type
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self.context = context
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self.hops = 0;
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self.destination = destination
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self.transport_id = transport_id
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self.data = data
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self.flags = self.get_packed_flags()
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self.raw = None
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self.packed = False
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self.sent = False
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self.create_receipt = create_receipt
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self.receipt = None
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self.fromPacked = False
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else:
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self.raw = data
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self.packed = True
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self.fromPacked = True
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self.create_receipt = False
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self.MTU = RNS.Reticulum.MTU
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self.sent_at = None
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self.packet_hash = None
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self.attached_interface = attached_interface
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self.receiving_interface = None
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self.rssi = None
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self.snr = None
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self.q = None
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def get_packed_flags(self):
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if self.context == Packet.LRPROOF:
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packed_flags = (self.header_type << 6) | (self.transport_type << 4) | (RNS.Destination.LINK << 2) | self.packet_type
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else:
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packed_flags = (self.header_type << 6) | (self.transport_type << 4) | (self.destination.type << 2) | self.packet_type
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return packed_flags
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def pack(self):
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self.destination_hash = self.destination.hash
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self.header = b""
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self.header += struct.pack("!B", self.flags)
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self.header += struct.pack("!B", self.hops)
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if self.context == Packet.LRPROOF:
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self.header += self.destination.link_id
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self.ciphertext = self.data
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else:
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if self.header_type == Packet.HEADER_1:
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self.header += self.destination.hash
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if self.packet_type == Packet.ANNOUNCE:
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# Announce packets are not encrypted
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self.ciphertext = self.data
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elif self.packet_type == Packet.LINKREQUEST:
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# Link request packets are not encrypted
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self.ciphertext = self.data
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elif self.packet_type == Packet.PROOF and self.context == Packet.RESOURCE_PRF:
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# Resource proofs are not encrypted
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self.ciphertext = self.data
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elif self.packet_type == Packet.PROOF and self.destination.type == RNS.Destination.LINK:
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# Packet proofs over links are not encrypted
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self.ciphertext = self.data
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elif self.context == Packet.RESOURCE:
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# A resource takes care of encryption
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# by itself
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self.ciphertext = self.data
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elif self.context == Packet.KEEPALIVE:
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# Keepalive packets contain no actual
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# data
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self.ciphertext = self.data
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elif self.context == Packet.CACHE_REQUEST:
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# Cache-requests are not encrypted
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self.ciphertext = self.data
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else:
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# In all other cases, we encrypt the packet
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# with the destination's encryption method
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self.ciphertext = self.destination.encrypt(self.data)
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if self.header_type == Packet.HEADER_2:
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if self.transport_id != None:
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self.header += self.transport_id
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self.header += self.destination.hash
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if self.packet_type == Packet.ANNOUNCE:
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# Announce packets are not encrypted
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self.ciphertext = self.data
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else:
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raise IOError("Packet with header type 2 must have a transport ID")
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self.header += bytes([self.context])
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self.raw = self.header + self.ciphertext
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if len(self.raw) > self.MTU:
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raise IOError("Packet size of "+str(len(self.raw))+" exceeds MTU of "+str(self.MTU)+" bytes")
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self.packed = True
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self.update_hash()
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def unpack(self):
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try:
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self.flags = self.raw[0]
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self.hops = self.raw[1]
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self.header_type = (self.flags & 0b01000000) >> 6
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self.transport_type = (self.flags & 0b00110000) >> 4
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self.destination_type = (self.flags & 0b00001100) >> 2
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self.packet_type = (self.flags & 0b00000011)
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DST_LEN = RNS.Reticulum.TRUNCATED_HASHLENGTH//8
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if self.header_type == Packet.HEADER_2:
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self.transport_id = self.raw[2:DST_LEN+2]
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self.destination_hash = self.raw[DST_LEN+2:2*DST_LEN+2]
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self.context = ord(self.raw[2*DST_LEN+2:2*DST_LEN+3])
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self.data = self.raw[2*DST_LEN+3:]
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else:
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self.transport_id = None
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self.destination_hash = self.raw[2:DST_LEN+2]
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self.context = ord(self.raw[DST_LEN+2:DST_LEN+3])
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self.data = self.raw[DST_LEN+3:]
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self.packed = False
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self.update_hash()
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return True
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except Exception as e:
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RNS.log("Received malformed packet, dropping it. The contained exception was: "+str(e), RNS.LOG_EXTREME)
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return False
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def send(self):
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"""
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Sends the packet.
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:returns: A :ref:`RNS.PacketReceipt<api-packetreceipt>` instance if *create_receipt* was set to *True* when the packet was instantiated, if not returns *None*. If the packet could not be sent *False* is returned.
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"""
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if not self.sent:
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if self.destination.type == RNS.Destination.LINK:
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if self.destination.status == RNS.Link.CLOSED:
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raise IOError("Attempt to transmit over a closed link")
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else:
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self.destination.last_outbound = time.time()
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self.destination.tx += 1
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self.destination.txbytes += len(self.data)
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if not self.packed:
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self.pack()
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if RNS.Transport.outbound(self):
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return self.receipt
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else:
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RNS.log("No interfaces could process the outbound packet", RNS.LOG_ERROR)
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self.sent = False
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self.receipt = None
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return False
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else:
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raise IOError("Packet was already sent")
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def resend(self):
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"""
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Re-sends the packet.
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:returns: A :ref:`RNS.PacketReceipt<api-packetreceipt>` instance if *create_receipt* was set to *True* when the packet was instantiated, if not returns *None*. If the packet could not be sent *False* is returned.
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"""
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if self.sent:
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# Re-pack the packet to obtain new ciphertext for
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# encrypted destinations
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self.pack()
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if RNS.Transport.outbound(self):
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return self.receipt
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else:
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RNS.log("No interfaces could process the outbound packet", RNS.LOG_ERROR)
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self.sent = False
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self.receipt = None
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return False
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else:
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raise IOError("Packet was not sent yet")
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def prove(self, destination=None):
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if self.fromPacked and hasattr(self, "destination") and self.destination:
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if self.destination.identity and self.destination.identity.prv:
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self.destination.identity.prove(self, destination)
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elif self.fromPacked and hasattr(self, "link") and self.link:
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self.link.prove_packet(self)
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else:
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RNS.log("Could not prove packet associated with neither a destination nor a link", RNS.LOG_ERROR)
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# Generates a special destination that allows Reticulum
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# to direct the proof back to the proved packet's sender
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def generate_proof_destination(self):
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return ProofDestination(self)
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def validate_proof_packet(self, proof_packet):
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return self.receipt.validate_proof_packet(proof_packet)
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def validate_proof(self, proof):
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return self.receipt.validate_proof(proof)
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def update_hash(self):
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self.packet_hash = self.get_hash()
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def get_hash(self):
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return RNS.Identity.full_hash(self.get_hashable_part())
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def getTruncatedHash(self):
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return RNS.Identity.truncated_hash(self.get_hashable_part())
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def get_hashable_part(self):
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hashable_part = bytes([self.raw[0] & 0b00001111])
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if self.header_type == Packet.HEADER_2:
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hashable_part += self.raw[(RNS.Identity.TRUNCATED_HASHLENGTH//8)+2:]
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else:
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hashable_part += self.raw[2:]
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return hashable_part
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class ProofDestination:
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def __init__(self, packet):
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self.hash = packet.get_hash()[:RNS.Reticulum.TRUNCATED_HASHLENGTH//8];
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self.type = RNS.Destination.SINGLE
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def encrypt(self, plaintext):
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return plaintext
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class PacketReceipt:
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"""
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The PacketReceipt class is used to receive notifications about
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:ref:`RNS.Packet<api-packet>` instances sent over the network. Instances
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of this class are never created manually, but always returned from
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the *send()* method of a :ref:`RNS.Packet<api-packet>` instance.
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"""
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# Receipt status constants
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FAILED = 0x00
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SENT = 0x01
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DELIVERED = 0x02
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CULLED = 0xFF
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EXPL_LENGTH = RNS.Identity.HASHLENGTH//8+RNS.Identity.SIGLENGTH//8
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IMPL_LENGTH = RNS.Identity.SIGLENGTH//8
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# Creates a new packet receipt from a sent packet
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def __init__(self, packet):
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self.hash = packet.get_hash()
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self.truncated_hash = packet.getTruncatedHash()
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self.sent = True
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self.sent_at = time.time()
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self.proved = False
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self.status = PacketReceipt.SENT
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self.destination = packet.destination
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self.callbacks = PacketReceiptCallbacks()
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self.concluded_at = None
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self.proof_packet = None
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if packet.destination.type == RNS.Destination.LINK:
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self.timeout = packet.destination.rtt * packet.destination.traffic_timeout_factor
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else:
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self.timeout = RNS.Reticulum.get_instance().get_first_hop_timeout(self.destination.hash)
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self.timeout += Packet.TIMEOUT_PER_HOP * RNS.Transport.hops_to(self.destination.hash)
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def get_status(self):
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"""
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:returns: The status of the associated :ref:`RNS.Packet<api-packet>` instance. Can be one of ``RNS.PacketReceipt.SENT``, ``RNS.PacketReceipt.DELIVERED``, ``RNS.PacketReceipt.FAILED`` or ``RNS.PacketReceipt.CULLED``.
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"""
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return self.status
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# Validate a proof packet
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def validate_proof_packet(self, proof_packet):
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if hasattr(proof_packet, "link") and proof_packet.link:
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return self.validate_link_proof(proof_packet.data, proof_packet.link, proof_packet)
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else:
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return self.validate_proof(proof_packet.data, proof_packet)
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# Validate a raw proof for a link
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def validate_link_proof(self, proof, link, proof_packet=None):
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# TODO: Hardcoded as explicit proofs for now
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if True or len(proof) == PacketReceipt.EXPL_LENGTH:
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# This is an explicit proof
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proof_hash = proof[:RNS.Identity.HASHLENGTH//8]
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signature = proof[RNS.Identity.HASHLENGTH//8:RNS.Identity.HASHLENGTH//8+RNS.Identity.SIGLENGTH//8]
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if proof_hash == self.hash:
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proof_valid = link.validate(signature, self.hash)
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if proof_valid:
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self.status = PacketReceipt.DELIVERED
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self.proved = True
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self.concluded_at = time.time()
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self.proof_packet = proof_packet
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link.last_proof = self.concluded_at
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if self.callbacks.delivery != None:
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try:
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self.callbacks.delivery(self)
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except Exception as e:
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RNS.log("An error occurred while evaluating external delivery callback for "+str(link), RNS.LOG_ERROR)
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RNS.log("The contained exception was: "+str(e), RNS.LOG_ERROR)
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return True
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else:
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return False
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else:
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return False
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elif len(proof) == PacketReceipt.IMPL_LENGTH:
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pass
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# TODO: Why is this disabled?
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# signature = proof[:RNS.Identity.SIGLENGTH//8]
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# proof_valid = self.link.validate(signature, self.hash)
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# if proof_valid:
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# self.status = PacketReceipt.DELIVERED
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# self.proved = True
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# self.concluded_at = time.time()
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# if self.callbacks.delivery != None:
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# self.callbacks.delivery(self)
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# RNS.log("valid")
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# return True
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# else:
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# RNS.log("invalid")
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# return False
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else:
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return False
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# Validate a raw proof
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def validate_proof(self, proof, proof_packet=None):
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if len(proof) == PacketReceipt.EXPL_LENGTH:
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# This is an explicit proof
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proof_hash = proof[:RNS.Identity.HASHLENGTH//8]
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signature = proof[RNS.Identity.HASHLENGTH//8:RNS.Identity.HASHLENGTH//8+RNS.Identity.SIGLENGTH//8]
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if proof_hash == self.hash:
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proof_valid = self.destination.identity.validate(signature, self.hash)
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if proof_valid:
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self.status = PacketReceipt.DELIVERED
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self.proved = True
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self.concluded_at = time.time()
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self.proof_packet = proof_packet
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if self.callbacks.delivery != None:
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try:
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self.callbacks.delivery(self)
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except Exception as e:
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RNS.log("Error while executing proof validated callback. The contained exception was: "+str(e), RNS.LOG_ERROR)
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return True
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else:
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return False
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else:
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return False
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elif len(proof) == PacketReceipt.IMPL_LENGTH:
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# This is an implicit proof
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if self.destination.identity == None:
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return False
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signature = proof[:RNS.Identity.SIGLENGTH//8]
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proof_valid = self.destination.identity.validate(signature, self.hash)
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if proof_valid:
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self.status = PacketReceipt.DELIVERED
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self.proved = True
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self.concluded_at = time.time()
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self.proof_packet = proof_packet
|
|
|
|
if self.callbacks.delivery != None:
|
|
try:
|
|
self.callbacks.delivery(self)
|
|
except Exception as e:
|
|
RNS.log("Error while executing proof validated callback. The contained exception was: "+str(e), RNS.LOG_ERROR)
|
|
|
|
return True
|
|
else:
|
|
return False
|
|
else:
|
|
return False
|
|
|
|
def get_rtt(self):
|
|
"""
|
|
:returns: The round-trip-time in seconds
|
|
"""
|
|
return self.concluded_at - self.sent_at
|
|
|
|
def is_timed_out(self):
|
|
return (self.sent_at+self.timeout < time.time())
|
|
|
|
def check_timeout(self):
|
|
if self.status == PacketReceipt.SENT and self.is_timed_out():
|
|
if self.timeout == -1:
|
|
self.status = PacketReceipt.CULLED
|
|
else:
|
|
self.status = PacketReceipt.FAILED
|
|
|
|
self.concluded_at = time.time()
|
|
|
|
if self.callbacks.timeout:
|
|
thread = threading.Thread(target=self.callbacks.timeout, args=(self,))
|
|
thread.daemon = True
|
|
thread.start()
|
|
|
|
|
|
def set_timeout(self, timeout):
|
|
"""
|
|
Sets a timeout in seconds
|
|
|
|
:param timeout: The timeout in seconds.
|
|
"""
|
|
self.timeout = float(timeout)
|
|
|
|
def set_delivery_callback(self, callback):
|
|
"""
|
|
Sets a function that gets called if a successfull delivery has been proven.
|
|
|
|
:param callback: A *callable* with the signature *callback(packet_receipt)*
|
|
"""
|
|
self.callbacks.delivery = callback
|
|
|
|
# Set a function that gets called if the
|
|
# delivery times out
|
|
def set_timeout_callback(self, callback):
|
|
"""
|
|
Sets a function that gets called if the delivery times out.
|
|
|
|
:param callback: A *callable* with the signature *callback(packet_receipt)*
|
|
"""
|
|
self.callbacks.timeout = callback
|
|
|
|
class PacketReceiptCallbacks:
|
|
def __init__(self):
|
|
self.delivery = None
|
|
self.timeout = None |