Reticulum/RNS/Packet.py

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import struct
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import time
import RNS
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class Packet:
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# Constants
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DATA = 0x00
ANNOUNCE = 0x01
LINKREQUEST = 0x02
PROOF = 0x03
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types = [DATA, ANNOUNCE, LINKREQUEST, PROOF]
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HEADER_1 = 0x00 # Normal header format
HEADER_2 = 0x01 # Header format used for link packets in transport
HEADER_3 = 0x02 # Reserved
HEADER_4 = 0x03 # Reserved
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header_types = [HEADER_1, HEADER_2, HEADER_3, HEADER_4]
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# Context types
NONE = 0x00
RESOURCE = 0x01
RESOURCE_ADV = 0x02
RESOURCE_REQ = 0x03
RESOURCE_HMU = 0x04
RESOURCE_PRF = 0x05
RESOURCE_ICL = 0x06
RESOURCE_RCL = 0x07
REQUEST = 0x08
RESPONSE = 0x09
COMMAND = 0x0A
COMMAND_STAT = 0x0B
KEEPALIVE = 0xFC
LINKCLOSE = 0xFD
LRRTT = 0xFE
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LRPROOF = 0xFF
HEADER_MAXSIZE = 23
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# Defaults
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TIMEOUT = 60
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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):
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if destination != None:
if transport_type == None:
transport_type = RNS.Transport.BROADCAST
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self.header_type = header_type
self.packet_type = packet_type
self.transport_type = transport_type
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self.context = context
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self.hops = 0;
self.destination = destination
self.transport_id = transport_id
self.data = data
self.flags = self.getPackedFlags()
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self.MTU = RNS.Reticulum.MTU
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self.raw = None
self.packed = False
self.sent = False
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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
self.packed = True
self.fromPacked = True
self.sent_at = None
self.packet_hash = None
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def getPackedFlags(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 | self.packet_type
else:
packed_flags = (self.header_type << 6) | (self.transport_type << 4) | (self.destination.type << 2) | self.packet_type
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return packed_flags
def pack(self):
self.header = ""
self.header += struct.pack("!B", self.flags)
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:
if self.header_type == Packet.HEADER_1:
self.header += self.destination.hash
if self.packet_type == Packet.ANNOUNCE:
# Announce packets are not encrypted
self.ciphertext = self.data
elif self.packet_type == Packet.PROOF and self.context == Packet.RESOURCE_PRF:
# Resource proofs are not encrypted
self.ciphertext = self.data
elif self.context == Packet.RESOURCE:
# A resource takes care of symmetric
# encryption by itself
self.ciphertext = self.data
elif self.context == Packet.KEEPALIVE:
# Keepalive packets contain no actual
# data
self.ciphertext = self.data
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else:
# In all other cases, we encrypt the packet
# with the destination's public key
self.ciphertext = self.destination.encrypt(self.data)
if self.header_type == Packet.HEADER_2:
if t_destination != None:
self.header += self.t_destination
else:
raise IOError("Packet with header type 2 must have a transport ID")
self.header += chr(self.context)
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self.raw = self.header + self.ciphertext
if len(self.raw) > self.MTU:
raise IOError("Packet size of "+str(len(self.raw))+" exceeds MTU of "+str(self.MTU)+" bytes")
self.packed = True
def unpack(self):
self.flags = ord(self.raw[0])
self.hops = ord(self.raw[1])
self.header_type = (self.flags & 0b11000000) >> 6
self.transport_type = (self.flags & 0b00110000) >> 4
self.destination_type = (self.flags & 0b00001100) >> 2
self.packet_type = (self.flags & 0b00000011)
if self.header_type == Packet.HEADER_2:
self.transport_id = self.raw[2:12]
self.destination_hash = self.raw[12:22]
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self.context = ord(self.raw[22:23])
self.data = self.raw[23:]
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else:
self.transport_id = None
self.destination_hash = self.raw[2:12]
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self.context = ord(self.raw[12:13])
self.data = self.raw[13:]
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self.packed = False
def send(self):
if not self.sent:
if self.destination.type == RNS.Destination.LINK:
if self.destination.status == RNS.Link.CLOSED:
raise IOError("Attempt to transmit over a closed link")
else:
self.destination.last_outbound = time.time()
self.destination.tx += 1
self.destination.txbytes += len(self.data)
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if not self.packed:
self.pack()
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if RNS.Transport.outbound(self):
return self.receipt
else:
# TODO: Don't raise error here, handle gracefully
raise IOError("Packet could not be sent! Do you have any outbound interfaces configured?")
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else:
raise IOError("Packet was already sent")
def resend(self):
if self.sent:
Transport.outbound(self.raw)
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 self.destination:
if self.destination.identity and self.destination.identity.prv:
self.destination.identity.prove(self, destination)
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# Generates a special destination that allows Reticulum
# to direct the proof back to the proved packet's sender
def generateProofDestination(self):
return ProofDestination(self)
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def validateProofPacket(self, proof_packet):
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return self.receipt.validateProofPacket(proof_packet)
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def validateProof(self, proof):
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return self.receipt.validateProof(proof)
def updateHash(self):
self.packet_hash = self.getHash()
def getHash(self):
return RNS.Identity.fullHash(self.getHashablePart())
def getHashablePart(self):
return self.raw[0:1]+self.raw[2:]
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class ProofDestination:
def __init__(self, packet):
self.hash = packet.getHash()[:10];
self.type = RNS.Destination.SINGLE
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def encrypt(self, plaintext):
return plaintext
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class PacketReceipt:
# Receipt status constants
FAILED = 0x00
SENT = 0x01
DELIVERED = 0x02
EXPL_LENGTH = RNS.Identity.HASHLENGTH/8+RNS.Identity.SIGLENGTH/8
IMPL_LENGTH = RNS.Identity.SIGLENGTH/8
# Creates a new packet receipt from a sent packet
def __init__(self, packet):
self.hash = packet.getHash()
self.sent = True
self.sent_at = time.time()
self.timeout = Packet.TIMEOUT
self.proved = False
self.status = PacketReceipt.SENT
self.destination = packet.destination
self.callbacks = PacketReceiptCallbacks()
self.concluded_at = None
# Validate a proof packet
def validateProofPacket(self, proof_packet):
return self.validateProof(proof_packet.data)
# Validate a raw proof
def validateProof(self, proof):
if len(proof) == PacketReceipt.EXPL_LENGTH:
# This is an explicit proof
proof_hash = proof[:RNS.Identity.HASHLENGTH/8]
signature = proof[RNS.Identity.HASHLENGTH/8:RNS.Identity.HASHLENGTH/8+RNS.Identity.SIGLENGTH/8]
if proof_hash == self.hash:
proof_valid = self.destination.identity.validate(signature, self.hash)
if proof_valid:
self.status = PacketReceipt.DELIVERED
self.proved = True
if self.callbacks.delivery != None:
self.callbacks.delivery(self)
return True
else:
return False
else:
return False
elif len(proof) == PacketReceipt.IMPL_LENGTH:
# This is an implicit proof
signature = proof[:RNS.Identity.SIGLENGTH/8]
proof_valid = self.destination.identity.validate(signature, self.hash)
if proof_valid:
self.status = PacketReceipt.DELIVERED
self.proved = True
if self.callbacks.delivery != None:
self.callbacks.delivery(self)
return True
else:
return False
else:
return False
def isTimedOut(self):
return (self.sent_at+self.timeout < time.time())
def checkTimeout(self):
if self.isTimedOut():
self.status = PacketReceipt.FAILED
self.concluded_at = time.time()
if self.callbacks.timeout:
self.callbacks.timeout(self)
# Set the timeout in seconds
def setTimeout(self, timeout):
self.timeout = float(timeout)
# Set a function that gets called when
# a successfull delivery has been proved
def delivery_callback(self, callback):
self.callbacks.delivery = callback
# Set a function that gets called if the
# delivery times out
def timeout_callback(self, callback):
self.callbacks.timeout = callback
class PacketReceiptCallbacks:
def __init__(self):
self.delivery = None
self.timeout = None