Reticulum/RNS/Transport.py
2021-08-19 14:10:37 +02:00

1195 lines
63 KiB
Python
Executable File

import os
import RNS
import time
import math
import struct
import threading
import traceback
from time import sleep
from .vendor import umsgpack as umsgpack
class Transport:
# Constants
BROADCAST = 0x00;
TRANSPORT = 0x01;
RELAY = 0x02;
TUNNEL = 0x03;
types = [BROADCAST, TRANSPORT, RELAY, TUNNEL]
REACHABILITY_UNREACHABLE = 0x00
REACHABILITY_DIRECT = 0x01
REACHABILITY_TRANSPORT = 0x02
APP_NAME = "rnstransport"
PATHFINDER_M = 18 # Max hops
PATHFINDER_C = 2.0 # Decay constant
PATHFINDER_R = 1 # Retransmit retries
PATHFINDER_T = 10 # Retry grace period
PATHFINDER_RW = 10 # Random window for announce rebroadcast
PATHFINDER_E = 60*15 # Path expiration in seconds
# TODO: Calculate an optimal number for this in
# various situations
LOCAL_REBROADCASTS_MAX = 2 # How many local rebroadcasts of an announce is allowed
PATH_REQUEST_GRACE = 0.35 # Grace time before a path announcement is made, allows directly reachable peers to respond first
PATH_REQUEST_RW = 2 # Path request random window
LINK_TIMEOUT = RNS.Link.KEEPALIVE * 2
REVERSE_TIMEOUT = 30*60 # Reverse table entries are removed after max 30 minutes
DESTINATION_TIMEOUT = 60*60*24*7 # Destination table entries are removed if unused for one week
MAX_RECEIPTS = 1024 # Maximum number of receipts to keep track of
interfaces = [] # All active interfaces
destinations = [] # All active destinations
pending_links = [] # Links that are being established
active_links = [] # Links that are active
packet_hashlist = [] # A list of packet hashes for duplicate detection
receipts = [] # Receipts of all outgoing packets for proof processing
# TODO: "destination_table" should really be renamed to "path_table"
# Notes on memory usage: 1 megabyte of memory can store approximately
# 55.100 path table entries or approximately 22.300 link table entries.
announce_table = {} # A table for storing announces currently waiting to be retransmitted
destination_table = {} # A lookup table containing the next hop to a given destination
reverse_table = {} # A lookup table for storing packet hashes used to return proofs and replies
link_table = {} # A lookup table containing hops for links
held_announces = {} # A table containing temporarily held announce-table entries
announce_handlers = [] # A table storing externally registered announce handlers
# Transport control destinations are used
# for control purposes like path requests
control_destinations = []
control_hashes = []
# Interfaces for communicating with
# local clients connected to a shared
# Reticulum instance
local_client_interfaces = []
jobs_locked = False
jobs_running = False
job_interval = 0.250
receipts_last_checked = 0.0
receipts_check_interval = 1.0
announces_last_checked = 0.0
announces_check_interval = 1.0
hashlist_maxsize = 1000000
tables_last_culled = 0.0
tables_cull_interval = 5.0
identity = None
@staticmethod
def start(reticulum_instance):
Transport.owner = reticulum_instance
if Transport.identity == None:
transport_identity_path = RNS.Reticulum.storagepath+"/transport_identity"
if os.path.isfile(transport_identity_path):
Transport.identity = RNS.Identity.from_file(transport_identity_path)
if Transport.identity == None:
RNS.log("No valid Transport Identity in storage, creating...", RNS.LOG_VERBOSE)
Transport.identity = RNS.Identity()
Transport.identity.to_file(transport_identity_path)
else:
RNS.log("Loaded Transport Identity from storage", RNS.LOG_VERBOSE)
packet_hashlist_path = RNS.Reticulum.storagepath+"/packet_hashlist"
if os.path.isfile(packet_hashlist_path):
try:
file = open(packet_hashlist_path, "rb")
Transport.packet_hashlist = umsgpack.unpackb(file.read())
file.close()
except Exception as e:
RNS.log("Could not load packet hashlist from storage, the contained exception was: "+str(e), RNS.LOG_ERROR)
# Create transport-specific destinations
Transport.path_request_destination = RNS.Destination(None, RNS.Destination.IN, RNS.Destination.PLAIN, Transport.APP_NAME, "path", "request")
Transport.path_request_destination.set_packet_callback(Transport.path_request_handler)
Transport.control_destinations.append(Transport.path_request_destination)
Transport.control_hashes.append(Transport.path_request_destination.hash)
thread = threading.Thread(target=Transport.jobloop)
thread.setDaemon(True)
thread.start()
if RNS.Reticulum.transport_enabled():
destination_table_path = RNS.Reticulum.storagepath+"/destination_table"
if os.path.isfile(destination_table_path) and not Transport.owner.is_connected_to_shared_instance:
serialised_destinations = []
try:
file = open(destination_table_path, "rb")
serialised_destinations = umsgpack.unpackb(file.read())
file.close()
for serialised_entry in serialised_destinations:
destination_hash = serialised_entry[0]
timestamp = serialised_entry[1]
received_from = serialised_entry[2]
hops = serialised_entry[3]
expires = serialised_entry[4]
random_blobs = serialised_entry[5]
receiving_interface = Transport.find_interface_from_hash(serialised_entry[6])
announce_packet = Transport.get_cached_packet(serialised_entry[7])
if announce_packet != None and receiving_interface != None:
announce_packet.unpack()
# We increase the hops, since reading a packet
# from cache is equivalent to receiving it again
# over an interface. It is cached with it's non-
# increased hop-count.
announce_packet.hops += 1
Transport.destination_table[destination_hash] = [timestamp, received_from, hops, expires, random_blobs, receiving_interface, announce_packet]
RNS.log("Loaded path table entry for "+RNS.prettyhexrep(destination_hash)+" from storage", RNS.LOG_DEBUG)
else:
RNS.log("Could not reconstruct path table entry from storage for "+RNS.prettyhexrep(destination_hash), RNS.LOG_DEBUG)
if announce_packet == None:
RNS.log("The announce packet could not be loaded from cache", RNS.LOG_DEBUG)
if receiving_interface == None:
RNS.log("The interface is no longer available", RNS.LOG_DEBUG)
if len(Transport.destination_table) == 1:
specifier = "entry"
else:
specifier = "entries"
RNS.log("Loaded "+str(len(Transport.destination_table))+" path table "+specifier+" from storage", RNS.LOG_VERBOSE)
except Exception as e:
RNS.log("Could not load destination table from storage, the contained exception was: "+str(e), RNS.LOG_ERROR)
RNS.log("Transport instance "+str(Transport.identity)+" started")
@staticmethod
def jobloop():
while (True):
Transport.jobs()
sleep(Transport.job_interval)
@staticmethod
def jobs():
outgoing = []
Transport.jobs_running = True
try:
if not Transport.jobs_locked:
# Process receipts list for timed-out packets
if time.time() > Transport.receipts_last_checked+Transport.receipts_check_interval:
while len(Transport.receipts) > Transport.MAX_RECEIPTS:
culled_receipt = Transport.receipts.pop(0)
culled_receipt.timeout = -1
receipt.check_timeout()
for receipt in Transport.receipts:
receipt.check_timeout()
if receipt.status != RNS.PacketReceipt.SENT:
Transport.receipts.remove(receipt)
Transport.receipts_last_checked = time.time()
# Process announces needing retransmission
if time.time() > Transport.announces_last_checked+Transport.announces_check_interval:
for destination_hash in Transport.announce_table:
announce_entry = Transport.announce_table[destination_hash]
if announce_entry[2] > Transport.PATHFINDER_R:
RNS.log("Dropping announce for "+RNS.prettyhexrep(destination_hash)+", retries exceeded", RNS.LOG_DEBUG)
Transport.announce_table.pop(destination_hash)
break
else:
if time.time() > announce_entry[1]:
announce_entry[1] = time.time() + math.pow(Transport.PATHFINDER_C, announce_entry[4]) + Transport.PATHFINDER_T + Transport.PATHFINDER_RW
announce_entry[2] += 1
packet = announce_entry[5]
block_rebroadcasts = announce_entry[7]
attached_interface = announce_entry[8]
announce_context = RNS.Packet.NONE
if block_rebroadcasts:
announce_context = RNS.Packet.PATH_RESPONSE
announce_data = packet.data
announce_identity = RNS.Identity.recall(packet.destination_hash)
announce_destination = RNS.Destination(announce_identity, RNS.Destination.OUT, RNS.Destination.SINGLE, "unknown", "unknown");
announce_destination.hash = packet.destination_hash
announce_destination.hexhash = announce_destination.hash.hex()
new_packet = RNS.Packet(
announce_destination,
announce_data,
RNS.Packet.ANNOUNCE,
context = announce_context,
header_type = RNS.Packet.HEADER_2,
transport_type = Transport.TRANSPORT,
transport_id = Transport.identity.hash,
attached_interface = attached_interface
)
new_packet.hops = announce_entry[4]
if block_rebroadcasts:
RNS.log("Rebroadcasting announce as path response for "+RNS.prettyhexrep(announce_destination.hash)+" with hop count "+str(new_packet.hops), RNS.LOG_DEBUG)
else:
RNS.log("Rebroadcasting announce for "+RNS.prettyhexrep(announce_destination.hash)+" with hop count "+str(new_packet.hops), RNS.LOG_DEBUG)
outgoing.append(new_packet)
# This handles an edge case where a peer sends a past
# request for a destination just after an announce for
# said destination has arrived, but before it has been
# rebroadcast locally. In such a case the actual announce
# is temporarily held, and then reinserted when the path
# request has been served to the peer.
if destination_hash in Transport.held_announces:
held_entry = Transport.held_announces.pop(destination_hash)
Transport.announce_table[destination_hash] = held_entry
RNS.log("Reinserting held announce into table", RNS.LOG_DEBUG)
Transport.announces_last_checked = time.time()
# Cull the packet hashlist if it has reached max size
while (len(Transport.packet_hashlist) > Transport.hashlist_maxsize):
Transport.packet_hashlist.pop(0)
if time.time() > Transport.tables_last_culled + Transport.tables_cull_interval:
# Cull the reverse table according to timeout
for truncated_packet_hash in Transport.reverse_table:
reverse_entry = Transport.reverse_table[truncated_packet_hash]
if time.time() > reverse_entry[2] + Transport.REVERSE_TIMEOUT:
Transport.reverse_table.pop(truncated_packet_hash)
# Cull the link table according to timeout
stale_links = []
for link_id in Transport.link_table:
link_entry = Transport.link_table[link_id]
if time.time() > link_entry[0] + Transport.LINK_TIMEOUT:
stale_links.append(link_id)
# Cull the path table
stale_paths = []
for destination_hash in Transport.destination_table:
destination_entry = Transport.destination_table[destination_hash]
attached_interface = destination_entry[5]
if time.time() > destination_entry[0] + Transport.DESTINATION_TIMEOUT:
stale_paths.append(destination_hash)
RNS.log("Path to "+RNS.prettyhexrep(destination_hash)+" timed out and was removed", RNS.LOG_DEBUG)
if not attached_interface in Transport.interfaces:
stale_paths.append(destination_hash)
RNS.log("Path to "+RNS.prettyhexrep(destination_hash)+" was removed since the attached interface no longer exists", RNS.LOG_DEBUG)
i = 0
for link_id in stale_links:
Transport.link_table.pop(link_id)
i += 1
if i > 0:
if i == 1:
RNS.log("Dropped "+str(i)+" link", RNS.LOG_DEBUG)
else:
RNS.log("Dropped "+str(i)+" links", RNS.LOG_DEBUG)
i = 0
for destination_hash in stale_paths:
Transport.destination_table.pop(destination_hash)
i += 1
if i > 0:
if i == 1:
RNS.log("Removed "+str(i)+" path", RNS.LOG_DEBUG)
else:
RNS.log("Removed "+str(i)+" paths", RNS.LOG_DEBUG)
Transport.tables_last_culled = time.time()
except Exception as e:
RNS.log("An exception occurred while running Transport jobs.", RNS.LOG_ERROR)
RNS.log("The contained exception was: "+str(e), RNS.LOG_ERROR)
traceback.print_exc()
Transport.jobs_running = False
for packet in outgoing:
packet.send()
@staticmethod
def outbound(packet):
while (Transport.jobs_running):
sleep(0.01)
Transport.jobs_locked = True
# TODO: This updateHash call might be redundant
packet.update_hash()
sent = False
# Check if we have a known path for the destination in the path table
if packet.packet_type != RNS.Packet.ANNOUNCE and packet.destination_hash in Transport.destination_table:
outbound_interface = Transport.destination_table[packet.destination_hash][5]
# If there's more than one hop to the destination, and we know
# a path, we insert the packet into transport by adding the next
# transport nodes address to the header, and modifying the flags.
# This rule applies both for "normal" transport, and when connected
# to a local shared Reticulum instance.
if Transport.destination_table[packet.destination_hash][2] > 1:
if packet.header_type == RNS.Packet.HEADER_1:
# Insert packet into transport
new_flags = (RNS.Packet.HEADER_2) << 6 | (Transport.TRANSPORT) << 4 | (packet.flags & 0b00001111)
new_raw = struct.pack("!B", new_flags)
new_raw += packet.raw[1:2]
new_raw += Transport.destination_table[packet.destination_hash][1]
new_raw += packet.raw[2:]
# TODO: Remove at some point
# RNS.log("Packet was inserted into transport via "+RNS.prettyhexrep(Transport.destination_table[packet.destination_hash][1])+" on: "+str(outbound_interface), RNS.LOG_EXTREME)
outbound_interface.processOutgoing(new_raw)
Transport.destination_table[packet.destination_hash][0] = time.time()
sent = True
# In the special case where we are connected to a local shared
# Reticulum instance, and the destination is one hop away, we
# also add transport headers to inject the packet into transport
# via the shared instance. Normally a packet for a destination
# one hop away would just be broadcast directly, but since we
# are "behind" a shared instance, we need to get that instance
# to transport it onto the network.
elif Transport.destination_table[packet.destination_hash][2] == 1 and Transport.owner.is_connected_to_shared_instance:
if packet.header_type == RNS.Packet.HEADER_1:
# Insert packet into transport
new_flags = (RNS.Packet.HEADER_2) << 6 | (Transport.TRANSPORT) << 4 | (packet.flags & 0b00001111)
new_raw = struct.pack("!B", new_flags)
new_raw += packet.raw[1:2]
new_raw += Transport.destination_table[packet.destination_hash][1]
new_raw += packet.raw[2:]
# TODO: Remove at some point
# RNS.log("Packet was inserted into transport via "+RNS.prettyhexrep(Transport.destination_table[packet.destination_hash][1])+" on: "+str(outbound_interface), RNS.LOG_EXTREME)
outbound_interface.processOutgoing(new_raw)
Transport.destination_table[packet.destination_hash][0] = time.time()
sent = True
# If none of the above applies, we know the destination is
# directly reachable, and also on which interface, so we
# simply transmit the packet directly on that one.
else:
outbound_interface.processOutgoing(packet.raw)
sent = True
# If we don't have a known path for the destination, we'll
# broadcast the packet on all outgoing interfaces, or the
# just the relevant interface if the packet has an attached
# interface, or belongs to a link.
else:
for interface in Transport.interfaces:
if interface.OUT:
should_transmit = True
if packet.destination.type == RNS.Destination.LINK:
if packet.destination.status == RNS.Link.CLOSED:
should_transmit = False
if interface != packet.destination.attached_interface:
should_transmit = False
if packet.attached_interface != None and interface != packet.attached_interface:
should_transmit = False
if should_transmit:
RNS.log("Transmitting "+str(len(packet.raw))+" bytes on: "+str(interface), RNS.LOG_EXTREME)
RNS.log("Hash is "+RNS.prettyhexrep(packet.packet_hash), RNS.LOG_EXTREME)
interface.processOutgoing(packet.raw)
sent = True
if sent:
packet.sent = True
packet.sent_at = time.time()
# Don't generate receipt if it has been explicitly disabled
if (packet.create_receipt == True and
# Only generate receipts for DATA packets
packet.packet_type == RNS.Packet.DATA and
# Don't generate receipts for PLAIN destinations
packet.destination.type != RNS.Destination.PLAIN and
# Don't generate receipts for link-related packets
not (packet.context >= RNS.Packet.KEEPALIVE and packet.context <= RNS.Packet.LRPROOF) and
# Don't generate receipts for resource packets
not (packet.context >= RNS.Packet.RESOURCE and packet.context <= RNS.Packet.RESOURCE_RCL)):
packet.receipt = RNS.PacketReceipt(packet)
Transport.receipts.append(packet.receipt)
Transport.cache(packet)
Transport.jobs_locked = False
return sent
@staticmethod
def packet_filter(packet):
# TODO: Think long and hard about this.
# Is it even strictly necessary with the current
# transport rules?
if packet.context == RNS.Packet.KEEPALIVE:
return True
if packet.context == RNS.Packet.RESOURCE_REQ:
return True
if packet.context == RNS.Packet.RESOURCE_PRF:
return True
if packet.context == RNS.Packet.RESOURCE:
return True
if packet.context == RNS.Packet.CACHE_REQUEST:
return True
if packet.destination_type == RNS.Destination.PLAIN:
return True
if not packet.packet_hash in Transport.packet_hashlist:
return True
else:
if packet.packet_type == RNS.Packet.ANNOUNCE:
return True
RNS.log("Filtered packet with hash "+RNS.prettyhexrep(packet.packet_hash), RNS.LOG_DEBUG)
return False
@staticmethod
def inbound(raw, interface=None):
while (Transport.jobs_running):
# TODO: Decrease this for performance
sleep(0.1)
Transport.jobs_locked = True
packet = RNS.Packet(None, raw)
packet.unpack()
packet.receiving_interface = interface
packet.hops += 1
RNS.log(str(interface)+" received packet with hash "+RNS.prettyhexrep(packet.packet_hash), RNS.LOG_EXTREME)
if len(Transport.local_client_interfaces) > 0:
if Transport.is_local_client_interface(interface):
packet.hops -= 1
elif Transport.interface_to_shared_instance(interface):
packet.hops -= 1
if Transport.packet_filter(packet):
Transport.packet_hashlist.append(packet.packet_hash)
Transport.cache(packet)
# Check special conditions for local clients connected
# through a shared Reticulum instance
from_local_client = (packet.receiving_interface in Transport.local_client_interfaces)
for_local_client = (packet.packet_type != RNS.Packet.ANNOUNCE) and (packet.destination_hash in Transport.destination_table and Transport.destination_table[packet.destination_hash][2] == 0)
for_local_client_link = (packet.packet_type != RNS.Packet.ANNOUNCE) and (packet.destination_hash in Transport.link_table and Transport.link_table[packet.destination_hash][4] in Transport.local_client_interfaces)
for_local_client_link |= (packet.packet_type != RNS.Packet.ANNOUNCE) and (packet.destination_hash in Transport.link_table and Transport.link_table[packet.destination_hash][2] in Transport.local_client_interfaces)
proof_for_local_client = (packet.destination_hash in Transport.reverse_table) and (Transport.reverse_table[packet.destination_hash][0] in Transport.local_client_interfaces)
# Plain broadcast packets from local clients are sent
# directly on all attached interfaces, since they are
# never injected into transport.
if not packet.destination_hash in Transport.control_hashes:
if packet.destination_type == RNS.Destination.PLAIN and packet.transport_type == Transport.BROADCAST:
# Send to all interfaces except the originator
if from_local_client:
for interface in Transport.interfaces:
if interface != packet.receiving_interface:
interface.processOutgoing(packet.raw)
# If the packet was not from a local client, send
# it directly to all local clients
else:
for interface in Transport.local_client_interfaces:
interface.processOutgoing(packet.raw)
# General transport handling. Takes care of directing
# packets according to transport tables and recording
# entries in reverse and link tables.
if RNS.Reticulum.transport_enabled() or from_local_client or for_local_client or for_local_client_link:
# If there is no transport id, but the packet is
# for a local client, we generate the transport
# id (it was stripped on the previous hop, since
# we "spoof" the hop count for clients behind a
# shared instance, so they look directly reach-
# able), and reinsert, so the normal transport
# implementation can handle the packet.
if packet.transport_id == None and for_local_client:
packet.transport_id = Transport.identity.hash
# If this is a cache request, and we can fullfill
# it, do so and stop processing. Otherwise resume
# normal processing.
if packet.context == RNS.Packet.CACHE_REQUEST:
if Transport.cache_request_packet(packet):
return
# If the packet is in transport, check whether we
# are the designated next hop, and process it
# accordingly if we are.
if packet.transport_id != None and packet.packet_type != RNS.Packet.ANNOUNCE:
if packet.transport_id == Transport.identity.hash:
RNS.log("Received packet in transport for "+RNS.prettyhexrep(packet.destination_hash)+" with matching transport ID, transporting it...", RNS.LOG_DEBUG)
if packet.destination_hash in Transport.destination_table:
next_hop = Transport.destination_table[packet.destination_hash][1]
remaining_hops = Transport.destination_table[packet.destination_hash][2]
RNS.log("Next hop to destination is "+RNS.prettyhexrep(next_hop)+" with "+str(remaining_hops)+" hops remaining, transporting it.", RNS.LOG_DEBUG)
if remaining_hops > 1:
# Just increase hop count and transmit
new_raw = packet.raw[0:1]
new_raw += struct.pack("!B", packet.hops)
new_raw += next_hop
new_raw += packet.raw[12:]
elif remaining_hops == 1:
# Strip transport headers and transmit
new_flags = (RNS.Packet.HEADER_1) << 6 | (Transport.BROADCAST) << 4 | (packet.flags & 0b00001111)
new_raw = struct.pack("!B", new_flags)
new_raw += struct.pack("!B", packet.hops)
new_raw += packet.raw[12:]
elif remaining_hops == 0:
# Just increase hop count and transmit
new_raw = packet.raw[0:1]
new_raw += struct.pack("!B", packet.hops)
new_raw += packet.raw[2:]
outbound_interface = Transport.destination_table[packet.destination_hash][5]
outbound_interface.processOutgoing(new_raw)
Transport.destination_table[packet.destination_hash][0] = time.time()
if packet.packet_type == RNS.Packet.LINKREQUEST:
# Entry format is
link_entry = [ time.time(), # 0: Timestamp,
next_hop, # 1: Next-hop transport ID
outbound_interface, # 2: Next-hop interface
remaining_hops, # 3: Remaining hops
packet.receiving_interface, # 4: Received on interface
packet.hops, # 5: Taken hops
packet.destination_hash, # 6: Original destination hash
False] # 7: Validated
Transport.link_table[packet.getTruncatedHash()] = link_entry
else:
# Entry format is
reverse_entry = [ packet.receiving_interface, # 0: Received on interface
outbound_interface, # 1: Outbound interface
time.time()] # 2: Timestamp
Transport.reverse_table[packet.getTruncatedHash()] = reverse_entry
else:
# TODO: There should probably be some kind of REJECT
# mechanism here, to signal to the source that their
# expected path failed.
RNS.log("Got packet in transport, but no known path to final destination. Dropping packet.", RNS.LOG_DEBUG)
# Link transport handling. Directs packets according
# to entries in the link tables
if packet.packet_type != RNS.Packet.ANNOUNCE and packet.packet_type != RNS.Packet.LINKREQUEST and packet.context != RNS.Packet.LRPROOF:
if packet.destination_hash in Transport.link_table:
link_entry = Transport.link_table[packet.destination_hash]
# If receiving and outbound interface is
# the same for this link, direction doesn't
# matter, and we simply send the packet on.
outbound_interface = None
if link_entry[2] == link_entry[4]:
# But check that taken hops matches one
# of the expectede values.
if packet.hops == link_entry[3] or packet.hops == link_entry[5]:
outbound_interface = link_entry[2]
else:
# If interfaces differ, we transmit on
# the opposite interface of what the
# packet was received on.
if packet.receiving_interface == link_entry[2]:
# Also check that expected hop count matches
if packet.hops == link_entry[3]:
outbound_interface = link_entry[4]
elif packet.receiving_interface == link_entry[4]:
# Also check that expected hop count matches
if packet.hops == link_entry[5]:
outbound_interface = link_entry[2]
if outbound_interface != None:
new_raw = packet.raw[0:1]
new_raw += struct.pack("!B", packet.hops)
new_raw += packet.raw[2:]
outbound_interface.processOutgoing(new_raw)
Transport.link_table[packet.destination_hash][0] = time.time()
else:
pass
# Announce handling. Handles logic related to incoming
# announces, queueing rebroadcasts of these, and removal
# of queued announce rebroadcasts once handed to the next node.
if packet.packet_type == RNS.Packet.ANNOUNCE:
local_destination = next((d for d in Transport.destinations if d.hash == packet.destination_hash), None)
if local_destination == None and RNS.Identity.validate_announce(packet):
if packet.transport_id != None:
received_from = packet.transport_id
# Check if this is a next retransmission from
# another node. If it is, we're removing the
# announce in question from our pending table
if RNS.Reticulum.transport_enabled() and packet.destination_hash in Transport.announce_table:
announce_entry = Transport.announce_table[packet.destination_hash]
if packet.hops-1 == announce_entry[4]:
RNS.log("Heard a local rebroadcast of announce for "+RNS.prettyhexrep(packet.destination_hash), RNS.LOG_DEBUG)
announce_entry[6] += 1
if announce_entry[6] >= Transport.LOCAL_REBROADCASTS_MAX:
RNS.log("Max local rebroadcasts of announce for "+RNS.prettyhexrep(packet.destination_hash)+" reached, dropping announce from our table", RNS.LOG_DEBUG)
Transport.announce_table.pop(packet.destination_hash)
if packet.hops-1 == announce_entry[4]+1 and announce_entry[2] > 0:
now = time.time()
if now < announce_entry[1]:
RNS.log("Rebroadcasted announce for "+RNS.prettyhexrep(packet.destination_hash)+" has been passed on to next node, no further tries needed", RNS.LOG_DEBUG)
Transport.announce_table.pop(packet.destination_hash)
else:
received_from = packet.destination_hash
# Check if this announce should be inserted into
# announce and destination tables
should_add = False
# First, check that the announce is not for a destination
# local to this system, and that hops are less than the max
if (not any(packet.destination_hash == d.hash for d in Transport.destinations) and packet.hops < Transport.PATHFINDER_M+1):
random_blob = packet.data[RNS.Identity.KEYSIZE//8+10:RNS.Identity.KEYSIZE//8+20]
random_blobs = []
if packet.destination_hash in Transport.destination_table:
random_blobs = Transport.destination_table[packet.destination_hash][4]
# If we already have a path to the announced
# destination, but the hop count is equal or
# less, we'll update our tables.
if packet.hops <= Transport.destination_table[packet.destination_hash][2]:
# Make sure we haven't heard the random
# blob before, so announces can't be
# replayed to forge paths.
# TODO: Check whether this approach works
# under all circumstances
if not random_blob in random_blobs:
should_add = True
else:
should_add = False
else:
# If an announce arrives with a larger hop
# count than we already have in the table,
# ignore it, unless the path is expired
if (time.time() > Transport.destination_table[packet.destination_hash][3]):
# We also check that the announce hash is
# different from ones we've already heard,
# to avoid loops in the network
if not random_blob in random_blobs:
# TODO: Check that this ^ approach actually
# works under all circumstances
RNS.log("Replacing destination table entry for "+str(RNS.prettyhexrep(packet.destination_hash))+" with new announce due to expired path", RNS.LOG_DEBUG)
should_add = True
else:
should_add = False
else:
should_add = False
else:
# If this destination is unknown in our table
# we should add it
should_add = True
if should_add:
now = time.time()
retries = 0
expires = now + Transport.PATHFINDER_E
announce_hops = packet.hops
local_rebroadcasts = 0
block_rebroadcasts = False
attached_interface = None
retransmit_timeout = now + math.pow(Transport.PATHFINDER_C, packet.hops) + (RNS.rand() * Transport.PATHFINDER_RW)
random_blobs.append(random_blob)
if (RNS.Reticulum.transport_enabled() or Transport.from_local_client(packet)) and packet.context != RNS.Packet.PATH_RESPONSE:
# If the announce is from a local client,
# we announce it immediately, but only one
# time.
if Transport.from_local_client(packet):
retransmit_timeout = now
retries = Transport.PATHFINDER_R
Transport.announce_table[packet.destination_hash] = [
now,
retransmit_timeout,
retries,
received_from,
announce_hops,
packet,
local_rebroadcasts,
block_rebroadcasts,
attached_interface
]
# If we have any local clients connected, we re-
# transmit the announce to them immediately
if (len(Transport.local_client_interfaces)):
announce_identity = RNS.Identity.recall(packet.destination_hash)
announce_destination = RNS.Destination(announce_identity, RNS.Destination.OUT, RNS.Destination.SINGLE, "unknown", "unknown");
announce_destination.hash = packet.destination_hash
announce_destination.hexhash = announce_destination.hash.hex()
announce_context = RNS.Packet.NONE
announce_data = packet.data
new_announce = RNS.Packet(
announce_destination,
announce_data,
RNS.Packet.ANNOUNCE,
context = announce_context,
header_type = RNS.Packet.HEADER_2,
transport_type = Transport.TRANSPORT,
transport_id = Transport.identity.hash,
attached_interface = attached_interface
)
new_announce.hops = packet.hops
new_announce.send()
Transport.destination_table[packet.destination_hash] = [now, received_from, announce_hops, expires, random_blobs, packet.receiving_interface, packet]
RNS.log("Path to "+RNS.prettyhexrep(packet.destination_hash)+" is now "+str(announce_hops)+" hops away via "+RNS.prettyhexrep(received_from)+" on "+str(packet.receiving_interface), RNS.LOG_VERBOSE)
# Call externally registered callbacks from apps
# wanting to know when an announce arrives
for handler in Transport.announce_handlers:
try:
# Check that the announced destination matches
# the handlers aspect filter
execute_callback = False
if handler.aspect_filter == None:
# If the handlers aspect filter is set to
# None, we execute the callback in all cases
execute_callback = True
else:
announce_identity = RNS.Identity.recall(packet.destination_hash)
handler_expected_hash = RNS.Destination.hash_from_name_and_identity(handler.aspect_filter, announce_identity)
if packet.destination_hash == handler_expected_hash:
execute_callback = True
if execute_callback:
handler.received_announce(
destination_hash=packet.destination_hash,
announced_identity=announce_identity,
app_data=RNS.Identity.recall_app_data(packet.destination_hash)
)
except Exception as e:
RNS.log("Error while processing external announce callback.", RNS.LOG_ERROR)
RNS.log("The contained exception was: "+str(e), RNS.LOG_ERROR)
# Handling for linkrequests to local destinations
elif packet.packet_type == RNS.Packet.LINKREQUEST:
for destination in Transport.destinations:
if destination.hash == packet.destination_hash and destination.type == packet.destination_type:
packet.destination = destination
destination.receive(packet)
# Handling for local data packets
elif packet.packet_type == RNS.Packet.DATA:
if packet.destination_type == RNS.Destination.LINK:
for link in Transport.active_links:
if link.link_id == packet.destination_hash:
packet.link = link
link.receive(packet)
else:
for destination in Transport.destinations:
if destination.hash == packet.destination_hash and destination.type == packet.destination_type:
packet.destination = destination
destination.receive(packet)
if destination.proof_strategy == RNS.Destination.PROVE_ALL:
packet.prove()
elif destination.proof_strategy == RNS.Destination.PROVE_APP:
if destination.callbacks.proof_requested:
if destination.callbacks.proof_requested(packet):
packet.prove()
# Handling for proofs and link-request proofs
elif packet.packet_type == RNS.Packet.PROOF:
if packet.context == RNS.Packet.LRPROOF:
# This is a link request proof, check if it
# needs to be transported
if (RNS.Reticulum.transport_enabled() or for_local_client_link or from_local_client) and packet.destination_hash in Transport.link_table:
link_entry = Transport.link_table[packet.destination_hash]
if packet.receiving_interface == link_entry[2]:
# TODO: Should we validate the LR proof at each transport
# step before transporting it?
RNS.log("Link request proof received on correct interface, transporting it via "+str(link_entry[4]), RNS.LOG_DEBUG)
new_raw = packet.raw[0:1]
new_raw += struct.pack("!B", packet.hops)
new_raw += packet.raw[2:]
Transport.link_table[packet.destination_hash][7] = True
link_entry[4].processOutgoing(new_raw)
else:
RNS.log("Link request proof received on wrong interface, not transporting it.", RNS.LOG_DEBUG)
else:
# Check if we can deliver it to a local
# pending link
for link in Transport.pending_links:
if link.link_id == packet.destination_hash:
link.validate_proof(packet)
elif packet.context == RNS.Packet.RESOURCE_PRF:
for link in Transport.active_links:
if link.link_id == packet.destination_hash:
link.receive(packet)
else:
if packet.destination_type == RNS.Destination.LINK:
for link in Transport.active_links:
if link.link_id == packet.destination_hash:
packet.link = link
if len(packet.data) == RNS.PacketReceipt.EXPL_LENGTH:
proof_hash = packet.data[:RNS.Identity.HASHLENGTH//8]
else:
proof_hash = None
# Check if this proof neds to be transported
if (RNS.Reticulum.transport_enabled() or from_local_client or proof_for_local_client) and packet.destination_hash in Transport.reverse_table:
reverse_entry = Transport.reverse_table.pop(packet.destination_hash)
if packet.receiving_interface == reverse_entry[1]:
RNS.log("Proof received on correct interface, transporting it via "+str(reverse_entry[0]), RNS.LOG_DEBUG)
new_raw = packet.raw[0:1]
new_raw += struct.pack("!B", packet.hops)
new_raw += packet.raw[2:]
reverse_entry[0].processOutgoing(new_raw)
else:
RNS.log("Proof received on wrong interface, not transporting it.", RNS.LOG_DEBUG)
for receipt in Transport.receipts:
receipt_validated = False
if proof_hash != None:
# Only test validation if hash matches
if receipt.hash == proof_hash:
receipt_validated = receipt.validate_proof_packet(packet)
else:
# In case of an implicit proof, we have
# to check every single outstanding receipt
receipt_validated = receipt.validate_proof_packet(packet)
if receipt_validated:
Transport.receipts.remove(receipt)
Transport.jobs_locked = False
@staticmethod
def register_destination(destination):
destination.MTU = RNS.Reticulum.MTU
if destination.direction == RNS.Destination.IN:
for registered_destination in Transport.destinations:
if destination.hash == registered_destination.hash:
raise KeyError("Attempt to register an already registered destination.")
Transport.destinations.append(destination)
@staticmethod
def deregister_destination(destination):
if destination in Transport.destinations:
Transport.destinations.remove(destination)
@staticmethod
def register_link(link):
RNS.log("Registering link "+str(link), RNS.LOG_DEBUG)
if link.initiator:
Transport.pending_links.append(link)
else:
Transport.active_links.append(link)
@staticmethod
def activate_link(link):
RNS.log("Activating link "+str(link), RNS.LOG_DEBUG)
if link in Transport.pending_links:
Transport.pending_links.remove(link)
Transport.active_links.append(link)
link.status = RNS.Link.ACTIVE
else:
RNS.log("Attempted to activate a link that was not in the pending table", RNS.LOG_ERROR)
@staticmethod
def register_announce_handler(handler):
"""
Registers an announce handler.
:param handler: Must be an object with an *aspect_filter* attribute and a *received_announce(destination_hash, announced_identity, app_data)* callable. See the :ref:`Announce Example<example-announce>` for more info.
"""
if hasattr(handler, "received_announce") and callable(handler.received_announce):
if hasattr(handler, "aspect_filter"):
Transport.announce_handlers.append(handler)
@staticmethod
def deregister_announce_handler(handler):
"""
Deregisters an announce handler.
:param handler: The announce handler to be deregistered.
"""
while handler in Transport.announce_handlers:
Transport.announce_handlers.remove(handler)
@staticmethod
def find_interface_from_hash(interface_hash):
for interface in Transport.interfaces:
if interface.get_hash() == interface_hash:
return interface
return None
@staticmethod
def should_cache(packet):
if packet.context == RNS.Packet.RESOURCE_PRF:
return True
return False
# When caching packets to storage, they are written
# exactly as they arrived over their interface. This
# means that they have not had their hop count
# increased yet! Take note of this when reading from
# the packet cache.
@staticmethod
def cache(packet, force_cache=False):
if RNS.Transport.should_cache(packet) or force_cache:
try:
packet_hash = RNS.hexrep(packet.get_hash(), delimit=False)
interface_reference = None
if packet.receiving_interface != None:
interface_reference = str(packet.receiving_interface)
file = open(RNS.Reticulum.cachepath+"/"+packet_hash, "wb")
file.write(umsgpack.packb([packet.raw, interface_reference]))
file.close()
except Exception as e:
RNS.log("Error writing packet to cache", RNS.LOG_ERROR)
RNS.log("The contained exception was: "+str(e))
@staticmethod
def get_cached_packet(packet_hash):
try:
packet_hash = RNS.hexrep(packet_hash, delimit=False)
path = RNS.Reticulum.cachepath+"/"+packet_hash
if os.path.isfile(path):
file = open(path, "rb")
cached_data = umsgpack.unpackb(file.read())
file.close()
packet = RNS.Packet(None, cached_data[0])
interface_reference = cached_data[1]
for interface in Transport.interfaces:
if str(interface) == interface_reference:
packet.receiving_interface = interface
return packet
else:
return None
except Exception as e:
RNS.log("Exception occurred while getting cached packet.", RNS.LOG_ERROR)
RNS.log("The contained exception was: "+str(e), RNS.LOG_ERROR)
@staticmethod
def cache_request_packet(packet):
if len(packet.data) == RNS.Identity.HASHLENGTH/8:
packet = Transport.get_cached_packet(packet.data)
if packet != None:
# If the packet was retrieved from the local
# cache, replay it to the Transport instance,
# so that it can be directed towards it original
# destination.
Transport.inbound(packet.raw, packet.receiving_interface)
return True
else:
return False
else:
return False
@staticmethod
def cache_request(packet_hash, destination):
cached_packet = Transport.get_cached_packet(packet_hash)
if cached_packet:
# The packet was found in the local cache,
# replay it to the Transport instance.
Transport.inbound(packet.raw, packet.receiving_interface)
else:
# The packet is not in the local cache,
# query the network.
RNS.Packet(destination, packet_hash, context = RNS.Packet.CACHE_REQUEST).send()
@staticmethod
def has_path(destination_hash):
"""
:param destination_hash: A destination hash as *bytes*.
:returns: *True* if a path to the destination is known, otherwise *False*.
"""
if destination_hash in Transport.destination_table:
return True
else:
return False
@staticmethod
def request_path(destination_hash):
"""
Requests a path to the destination from the network. If
another reachable peer on the network knows a path, it
will announce it.
:param destination_hash: A destination hash as *bytes*.
"""
path_request_data = destination_hash + RNS.Identity.get_random_hash()
path_request_dst = RNS.Destination(None, RNS.Destination.OUT, RNS.Destination.PLAIN, Transport.APP_NAME, "path", "request")
packet = RNS.Packet(path_request_dst, path_request_data, packet_type = RNS.Packet.DATA, transport_type = RNS.Transport.BROADCAST, header_type = RNS.Packet.HEADER_1)
packet.send()
@staticmethod
def request_path_on_interface(destination_hash, interface):
path_request_data = destination_hash + RNS.Identity.get_random_hash()
path_request_dst = RNS.Destination(None, RNS.Destination.OUT, RNS.Destination.PLAIN, Transport.APP_NAME, "path", "request")
packet = RNS.Packet(path_request_dst, path_request_data, packet_type = RNS.Packet.DATA, transport_type = RNS.Transport.BROADCAST, header_type = RNS.Packet.HEADER_1, attached_interface = interface)
packet.send()
@staticmethod
def path_request_handler(data, packet):
if len(data) >= RNS.Identity.TRUNCATED_HASHLENGTH//8:
Transport.path_request(
data[:RNS.Identity.TRUNCATED_HASHLENGTH//8],
Transport.from_local_client(packet),
packet.receiving_interface
)
@staticmethod
def path_request(destination_hash, is_from_local_client, attached_interface):
RNS.log("Path request for "+RNS.prettyhexrep(destination_hash), RNS.LOG_DEBUG)
local_destination = next((d for d in Transport.destinations if d.hash == destination_hash), None)
if local_destination != None:
RNS.log("Destination is local to this system, announcing", RNS.LOG_DEBUG)
local_destination.announce(path_response=True)
elif (RNS.Reticulum.transport_enabled() or is_from_local_client) and destination_hash in Transport.destination_table:
RNS.log("Path found, inserting announce for transmission", RNS.LOG_DEBUG)
packet = Transport.destination_table[destination_hash][6]
received_from = Transport.destination_table[destination_hash][5]
now = time.time()
retries = Transport.PATHFINDER_R
local_rebroadcasts = 0
block_rebroadcasts = True
announce_hops = packet.hops
if is_from_local_client:
retransmit_timeout = now
else:
# TODO: Look at this timing
retransmit_timeout = now + Transport.PATH_REQUEST_GRACE # + (RNS.rand() * Transport.PATHFINDER_RW)
# This handles an edge case where a peer sends a past
# request for a destination just after an announce for
# said destination has arrived, but before it has been
# rebroadcast locally. In such a case the actual announce
# is temporarily held, and then reinserted when the path
# request has been served to the peer.
if packet.destination_hash in Transport.announce_table:
held_entry = Transport.announce_table[packet.destination_hash]
Transport.held_announces[packet.destination_hash] = held_entry
Transport.announce_table[packet.destination_hash] = [now, retransmit_timeout, retries, received_from, announce_hops, packet, local_rebroadcasts, block_rebroadcasts, attached_interface]
elif is_from_local_client:
# Forward path request on all interfaces
# except the local client
for interface in Transport.interfaces:
if not interface == attached_interface:
Transport.request_path_on_interface(destination_hash, interface)
elif not is_from_local_client and len(Transport.local_client_interfaces) > 0:
# Forward the path request on all local
# client interfaces
for interface in Transport.local_client_interfaces:
Transport.request_path_on_interface(destination_hash, interface)
else:
RNS.log("No known path to requested destination, ignoring request", RNS.LOG_DEBUG)
@staticmethod
def from_local_client(packet):
if hasattr(packet.receiving_interface, "parent_interface"):
return Transport.is_local_client_interface(packet.receiving_interface)
else:
return False
@staticmethod
def is_local_client_interface(interface):
if hasattr(interface, "parent_interface"):
if hasattr(interface.parent_interface, "is_local_shared_instance"):
return True
else:
return False
else:
return False
@staticmethod
def interface_to_shared_instance(interface):
if hasattr(interface, "is_connected_to_shared_instance"):
return True
else:
return False
@staticmethod
def exit_handler():
RNS.log("Saving packet hashlist to storage...", RNS.LOG_VERBOSE)
try:
packet_hashlist_path = RNS.Reticulum.storagepath+"/packet_hashlist"
file = open(packet_hashlist_path, "wb")
file.write(umsgpack.packb(Transport.packet_hashlist))
file.close()
RNS.log("Done packet hashlist to storage", RNS.LOG_VERBOSE)
except Exception as e:
RNS.log("Could not save packet hashlist to storage, the contained exception was: "+str(e), RNS.LOG_ERROR)
if not Transport.owner.is_connected_to_shared_instance:
RNS.log("Saving path table to storage...", RNS.LOG_VERBOSE)
try:
serialised_destinations = []
for destination_hash in Transport.destination_table:
# Get the destination entry from the destination table
de = Transport.destination_table[destination_hash]
interface_hash = de[5].get_hash()
# Only store destination table entry if the associated
# interface is still active
interface = Transport.find_interface_from_hash(interface_hash)
if interface != None:
# Get the destination entry from the destination table
de = Transport.destination_table[destination_hash]
timestamp = de[0]
received_from = de[1]
hops = de[2]
expires = de[3]
random_blobs = de[4]
packet_hash = de[6].get_hash()
serialised_entry = [
destination_hash,
timestamp,
received_from,
hops,
expires,
random_blobs,
interface_hash,
packet_hash
]
serialised_destinations.append(serialised_entry)
Transport.cache(de[6], force_cache=True)
destination_table_path = RNS.Reticulum.storagepath+"/destination_table"
file = open(destination_table_path, "wb")
file.write(umsgpack.packb(serialised_destinations))
file.close()
RNS.log("Done saving "+str(len(serialised_destinations))+" path table entries to storage", RNS.LOG_VERBOSE)
except Exception as e:
RNS.log("Could not save path table to storage, the contained exception was: "+str(e), RNS.LOG_ERROR)