Implemented link peer identification

This commit is contained in:
Mark Qvist 2021-08-19 14:10:37 +02:00
parent 772ae44ab8
commit 384a7db974
7 changed files with 376 additions and 3 deletions

310
Examples/Identify.py Normal file
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@ -0,0 +1,310 @@
##########################################################
# This RNS example demonstrates how to set up a link to #
# a destination, and identify the initiator to it's peer #
##########################################################
import os
import sys
import time
import argparse
import RNS
# Let's define an app name. We'll use this for all
# destinations we create. Since this echo example
# is part of a range of example utilities, we'll put
# them all within the app namespace "example_utilities"
APP_NAME = "example_utilities"
##########################################################
#### Server Part #########################################
##########################################################
# A reference to the latest client link that connected
latest_client_link = None
# This initialisation is executed when the users chooses
# to run as a server
def server(configpath):
# We must first initialise Reticulum
reticulum = RNS.Reticulum(configpath)
# Randomly create a new identity for our link example
server_identity = RNS.Identity()
# We create a destination that clients can connect to. We
# want clients to create links to this destination, so we
# need to create a "single" destination type.
server_destination = RNS.Destination(
server_identity,
RNS.Destination.IN,
RNS.Destination.SINGLE,
APP_NAME,
"identifyexample"
)
# We configure a function that will get called every time
# a new client creates a link to this destination.
server_destination.set_link_established_callback(client_connected)
# Everything's ready!
# Let's Wait for client requests or user input
server_loop(server_destination)
def server_loop(destination):
# Let the user know that everything is ready
RNS.log(
"Link identification example "+
RNS.prettyhexrep(destination.hash)+
" running, waiting for a connection."
)
RNS.log("Hit enter to manually send an announce (Ctrl-C to quit)")
# We enter a loop that runs until the users exits.
# If the user hits enter, we will announce our server
# destination on the network, which will let clients
# know how to create messages directed towards it.
while True:
entered = input()
destination.announce()
RNS.log("Sent announce from "+RNS.prettyhexrep(destination.hash))
# When a client establishes a link to our server
# destination, this function will be called with
# a reference to the link.
def client_connected(link):
global latest_client_link
RNS.log("Client connected")
link.set_link_closed_callback(client_disconnected)
link.set_packet_callback(server_packet_received)
link.set_remote_identified_callback(remote_identified)
latest_client_link = link
def client_disconnected(link):
RNS.log("Client disconnected")
def remote_identified(identity):
RNS.log("Remote identified as: "+str(identity))
def server_packet_received(message, packet):
global latest_client_link
# Get the originating identity for display
remote_peer = "unidentified peer"
if packet.link.get_remote_identity() != None:
remote_peer = str(packet.link.get_remote_identity())
# When data is received over any active link,
# it will all be directed to the last client
# that connected.
text = message.decode("utf-8")
RNS.log("Received data from "+remote_peer+": "+text)
reply_text = "I received \""+text+"\" over the link from "+remote_peer
reply_data = reply_text.encode("utf-8")
RNS.Packet(latest_client_link, reply_data).send()
##########################################################
#### Client Part #########################################
##########################################################
# A reference to the server link
server_link = None
# A reference to the client identity
client_identity = None
# This initialisation is executed when the users chooses
# to run as a client
def client(destination_hexhash, configpath):
global client_identity
# We need a binary representation of the destination
# hash that was entered on the command line
try:
if len(destination_hexhash) != 20:
raise ValueError("Destination length is invalid, must be 20 hexadecimal characters (10 bytes)")
destination_hash = bytes.fromhex(destination_hexhash)
except:
RNS.log("Invalid destination entered. Check your input!\n")
exit()
# We must first initialise Reticulum
reticulum = RNS.Reticulum(configpath)
# Create a new client identity
client_identity = RNS.Identity()
RNS.log(
"Client created new identity "+
str(client_identity)
)
# Check if we know a path to the destination
if not RNS.Transport.has_path(destination_hash):
RNS.log("Destination is not yet known. Requesting path and waiting for announce to arrive...")
RNS.Transport.request_path(destination_hash)
while not RNS.Transport.has_path(destination_hash):
time.sleep(0.1)
# Recall the server identity
server_identity = RNS.Identity.recall(destination_hash)
# Inform the user that we'll begin connecting
RNS.log("Establishing link with server...")
# When the server identity is known, we set
# up a destination
server_destination = RNS.Destination(
server_identity,
RNS.Destination.OUT,
RNS.Destination.SINGLE,
APP_NAME,
"identifyexample"
)
# And create a link
link = RNS.Link(server_destination)
# We set a callback that will get executed
# every time a packet is received over the
# link
link.set_packet_callback(client_packet_received)
# We'll also set up functions to inform the
# user when the link is established or closed
link.set_link_established_callback(link_established)
link.set_link_closed_callback(link_closed)
# Everything is set up, so let's enter a loop
# for the user to interact with the example
client_loop()
def client_loop():
global server_link
# Wait for the link to become active
while not server_link:
time.sleep(0.1)
should_quit = False
while not should_quit:
try:
print("> ", end=" ")
text = input()
# Check if we should quit the example
if text == "quit" or text == "q" or text == "exit":
should_quit = True
server_link.teardown()
# If not, send the entered text over the link
if text != "":
data = text.encode("utf-8")
if len(data) <= RNS.Link.MDU:
RNS.Packet(server_link, data).send()
else:
RNS.log(
"Cannot send this packet, the data size of "+
str(len(data))+" bytes exceeds the link packet MDU of "+
str(RNS.Link.MDU)+" bytes",
RNS.LOG_ERROR
)
except Exception as e:
RNS.log("Error while sending data over the link: "+str(e))
should_quit = True
server_link.teardown()
# This function is called when a link
# has been established with the server
def link_established(link):
# We store a reference to the link
# instance for later use
global server_link, client_identity
server_link = link
# Inform the user that the server is
# connected
RNS.log("Link established with server, identifying to remote peer...")
link.identify(client_identity)
# When a link is closed, we'll inform the
# user, and exit the program
def link_closed(link):
if link.teardown_reason == RNS.Link.TIMEOUT:
RNS.log("The link timed out, exiting now")
elif link.teardown_reason == RNS.Link.DESTINATION_CLOSED:
RNS.log("The link was closed by the server, exiting now")
else:
RNS.log("Link closed, exiting now")
RNS.Reticulum.exit_handler()
time.sleep(1.5)
os._exit(0)
# When a packet is received over the link, we
# simply print out the data.
def client_packet_received(message, packet):
text = message.decode("utf-8")
RNS.log("Received data on the link: "+text)
print("> ", end=" ")
sys.stdout.flush()
##########################################################
#### Program Startup #####################################
##########################################################
# This part of the program runs at startup,
# and parses input of from the user, and then
# starts up the desired program mode.
if __name__ == "__main__":
try:
parser = argparse.ArgumentParser(description="Simple link example")
parser.add_argument(
"-s",
"--server",
action="store_true",
help="wait for incoming link requests from clients"
)
parser.add_argument(
"--config",
action="store",
default=None,
help="path to alternative Reticulum config directory",
type=str
)
parser.add_argument(
"destination",
nargs="?",
default=None,
help="hexadecimal hash of the server destination",
type=str
)
args = parser.parse_args()
if args.config:
configarg = args.config
else:
configarg = None
if args.server:
server(configarg)
else:
if (args.destination == None):
print("")
parser.print_help()
print("")
else:
client(args.destination, configarg)
except KeyboardInterrupt:
print("")
exit()

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@ -23,6 +23,7 @@ class LinkCallbacks:
self.resource = None
self.resource_started = None
self.resource_concluded = None
self.remote_identified = None
class Link:
"""
@ -125,6 +126,7 @@ class Link:
self.owner = owner
self.destination = destination
self.attached_interface = None
self.__remote_identity = None
self.__encryption_disabled = False
if self.destination == None:
self.initiator = False
@ -226,6 +228,7 @@ class Link:
if self.destination.identity.validate(signature, signed_data):
self.rtt = time.time() - self.request_time
self.attached_interface = packet.receiving_interface
self.__remote_identity = self.destination.identity
RNS.Transport.activate_link(self)
RNS.log("Link "+str(self)+" established with "+str(self.destination)+", RTT is "+str(self.rtt), RNS.LOG_VERBOSE)
rtt_data = umsgpack.packb(self.rtt)
@ -243,6 +246,25 @@ class Link:
RNS.log("Invalid link proof signature received by "+str(self)+". Ignoring.", RNS.LOG_DEBUG)
def identify(self, identity):
"""
Identifies the initiator of the link to the remote peer. This can only happen
once the link has been established, and is carried out over the encrypted link.
The identity is only revealed to the remote peer, and initiator anonymity is
thus preserved. This method can be used for authentication.
:param identity: An RNS.Identity instance to identify as.
"""
if self.initiator:
signed_data = self.link_id + identity.get_public_key()
signature = identity.sign(signed_data)
proof_data = identity.get_public_key() + signature
proof = RNS.Packet(self, proof_data, RNS.Packet.DATA, context = RNS.Packet.LINKIDENTIFY)
proof.send()
self.had_outbound()
def rtt_packet(self, packet):
try:
# TODO: This is crude, we should use the delta
@ -286,6 +308,12 @@ class Link:
"""
return min(self.no_inbound_for(), self.no_outbound_for())
def get_remote_identity(self):
"""
:returns: The identity of the remote peer, if it is known
"""
return self.__remote_identity
def had_outbound(self):
self.last_outbound = time.time()
@ -424,6 +452,21 @@ class Link:
if self.destination.callbacks.proof_requested:
self.destination.callbacks.proof_requested(packet)
elif packet.context == RNS.Packet.LINKIDENTIFY:
plaintext = self.decrypt(packet.data)
if not self.initiator and len(plaintext) == RNS.Identity.KEYSIZE//8 + RNS.Identity.SIGLENGTH//8:
public_key = plaintext[:RNS.Identity.KEYSIZE//8]
signed_data = self.link_id+public_key
signature = plaintext[RNS.Identity.KEYSIZE//8:RNS.Identity.KEYSIZE//8+RNS.Identity.SIGLENGTH//8]
identity = RNS.Identity(create_keys=False)
identity.load_public_key(public_key)
if identity.validate(signature, signed_data):
self.__remote_identity = identity
if self.callbacks.remote_identified != None:
self.callbacks.remote_identified(self.__remote_identity)
elif packet.context == RNS.Packet.LRRTT:
if not self.initiator:
self.rtt_packet(packet)
@ -574,6 +617,15 @@ class Link:
"""
self.callbacks.resource_concluded = callback
def set_remote_identified_callback(self, callback):
"""
Registers a function to be called when an initiating peer has
identified over this link.
:param callback: A function or method with the signature *callback(identity)* to be called.
"""
self.callbacks.remote_identified = callback
def resource_concluded(self, resource):
if resource in self.incoming_resources:
self.incoming_resources.remove(resource)

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@ -56,7 +56,8 @@ class Packet:
PATH_RESPONSE = 0x0B # Packet is a response to a path request
COMMAND = 0x0C # Packet is a command
COMMAND_STATUS = 0x0D # Packet is a status of an executed command
KEEPALIVE = 0xFB # Packet is a keepalive packet
KEEPALIVE = 0xFA # Packet is a keepalive packet
LINKIDENTIFY = 0xFB # Packet is a link peer identification proof
LINKCLOSE = 0xFC # Packet is a link close message
LINKPROOF = 0xFD # Packet is a link packet proof
LRRTT = 0xFE # Packet is a link request round-trip time measurement

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@ -49,6 +49,8 @@ class Transport:
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

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@ -5,6 +5,8 @@ import time
import random
import threading
from ._version import __version__
from .Reticulum import Reticulum
from .Identity import Identity
from .Link import Link
@ -60,6 +62,9 @@ def loglevelname(level):
return "Unknown"
def version():
return __version__
def log(msg, level=3, _override_destination = False):
global _always_override_destination
@ -68,7 +73,7 @@ def log(msg, level=3, _override_destination = False):
logstring = "["+time.strftime(logtimefmt)+"] ["+loglevelname(level)+"] "+msg
logging_lock.acquire()
if (logdest == LOG_STDOUT or _always_override_destination):
if (logdest == LOG_STDOUT or _always_override_destination or _override_destination):
print(logstring)
logging_lock.release()

1
RNS/_version.py Normal file
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@ -0,0 +1 @@
__version__ = "0.2.2"

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@ -1,11 +1,13 @@
import setuptools
exec(open("RNS/_version.py", "r").read())
with open("README.md", "r") as fh:
long_description = fh.read()
setuptools.setup(
name="rns",
version="0.2.1",
version=__version__,
author="Mark Qvist",
author_email="mark@unsigned.io",
description="Self-configuring, encrypted and resilient mesh networking stack for LoRa, packet radio, WiFi and everything in between",