Implemented RTT measurements on link establishment and link teardown procedure
This commit is contained in:
Mark Qvist
parent
de8d9cf722
commit
ece4f732f4
179
RNS/Link.py
179
RNS/Link.py
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@ -4,7 +4,9 @@ from cryptography.hazmat.primitives import serialization
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from cryptography.hazmat.primitives.asymmetric import ec
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from cryptography.hazmat.primitives.kdf.hkdf import HKDF
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from cryptography.fernet import Fernet
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import vendor.umsgpack as umsgpack
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import base64
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import time
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import RNS
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import traceback
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@ -12,6 +14,7 @@ import traceback
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class LinkCallbacks:
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def __init__(self):
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self.link_established = None
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self.link_closed = None
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self.packet = None
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self.resource_started = None
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self.resource_concluded = None
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@ -21,8 +24,11 @@ class Link:
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ECPUBSIZE = 91
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BLOCKSIZE = 16
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PENDING = 0x00
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ACTIVE = 0x01
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PENDING = 0x00
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HANDSHAKE = 0x01
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ACTIVE = 0x02
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STALE = 0x03
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CLOSED = 0x04
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ACCEPT_NONE = 0x00
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ACCEPT_APP = 0x01
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@ -39,6 +45,7 @@ class Link:
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link.handshake()
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link.attached_interface = packet.receiving_interface
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link.prove()
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link.request_time = time.time()
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RNS.Transport.registerLink(link)
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if link.owner.callbacks.link_established != None:
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link.owner.callbacks.link_established(link)
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@ -92,6 +99,7 @@ class Link:
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self.packet.pack()
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self.setLinkID(self.packet)
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RNS.Transport.registerLink(self)
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self.request_time = time.time()
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self.packet.send()
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RNS.log("Link request "+RNS.prettyhexrep(self.link_id)+" sent to "+str(self.destination), RNS.LOG_VERBOSE)
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@ -106,6 +114,7 @@ class Link:
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self.hash = self.link_id
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def handshake(self):
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self.status = Link.HANDSHAKE
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self.shared_key = self.prv.exchange(ec.ECDH(), self.peer_pub)
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self.derived_key = HKDF(
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algorithm=hashes.SHA256(),
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@ -131,78 +140,139 @@ class Link:
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if self.destination.identity.validate(signature, signed_data):
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self.loadPeer(peer_pub_bytes)
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self.handshake()
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self.rtt = time.time() - self.request_time
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self.attached_interface = packet.receiving_interface
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RNS.Transport.activateLink(self)
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RNS.log("Link "+str(self)+" established with "+str(self.destination), RNS.LOG_VERBOSE)
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RNS.log("Link "+str(self)+" established with "+str(self.destination)+", RTT is "+str(self.rtt), RNS.LOG_VERBOSE)
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rtt_data = umsgpack.packb(self.rtt)
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rtt_packet = RNS.Packet(self, rtt_data, context=RNS.Packet.LRRTT)
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rtt_packet.send()
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self.status = Link.ACTIVE
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if self.callbacks.link_established != None:
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self.callbacks.link_established(self)
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else:
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RNS.log("Invalid link proof signature received by "+str(self), RNS.LOG_VERBOSE)
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# TODO: should we really do this, or just wait
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# for a valid one? Needs analysis.
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self.teardown()
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def rtt_packet(self, packet):
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try:
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# TODO: This is crude, we should use the delta
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# to model a more representative per-bit round
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# trip time, and use that to set a sensible RTT
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# expectancy for the link. This will have to do
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# for now though.
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measured_rtt = time.time() - self.request_time
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plaintext = self.decrypt(packet.data)
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rtt = umsgpack.unpackb(plaintext)
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#RNS.log("Measured RTT is "+str(measured_rtt)+", received RTT is "+str(rtt))
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self.rtt = max(measured_rtt, rtt)
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self.status = Link.ACTIVE
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except Exception as e:
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self.teardown()
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def getSalt(self):
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return self.link_id
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def getContext(self):
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return None
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def teardown(self):
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if self.status != Link.PENDING:
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teardown_packet = RNS.Packet(self, self.link_id, context=RNS.Packet.LINKCLOSE)
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teardown_packet.send()
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self.status = Link.CLOSED
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self.link_closed()
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def teardown_packet(self, packet):
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try:
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plaintext = self.decrypt(packet.data)
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if plaintext == self.link_id:
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self.status = Link.CLOSED
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self.link_closed()
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except Exception as e:
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pass
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def link_closed(self):
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self.prv = None
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self.pub = None
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self.pub_bytes = None
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self.shared_key = None
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self.derived_key = None
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if self.callbacks.link_closed != None:
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self.callbacks.link_closed(self)
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def receive(self, packet):
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if packet.receiving_interface != self.attached_interface:
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RNS.log("Link-associated packet received on unexpected interface! Someone might be trying to manipulate your communication!", RNS.LOG_ERROR)
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else:
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if packet.packet_type == RNS.Packet.DATA:
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if packet.context == RNS.Packet.NONE:
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plaintext = self.decrypt(packet.data)
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if (self.callbacks.packet != None):
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self.callbacks.packet(plaintext, packet)
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if not self.status == Link.CLOSED:
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if packet.receiving_interface != self.attached_interface:
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RNS.log("Link-associated packet received on unexpected interface! Someone might be trying to manipulate your communication!", RNS.LOG_ERROR)
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else:
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if packet.packet_type == RNS.Packet.DATA:
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if packet.context == RNS.Packet.NONE:
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plaintext = self.decrypt(packet.data)
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if (self.callbacks.packet != None):
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self.callbacks.packet(plaintext, packet)
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elif packet.context == RNS.Packet.RESOURCE_ADV:
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packet.plaintext = self.decrypt(packet.data)
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if self.resource_strategy == Link.ACCEPT_NONE:
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pass
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elif self.resource_strategy == Link.ACCEPT_APP:
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if self.callbacks.resource != None:
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self.callbacks.resource(packet)
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elif self.resource_strategy == Link.ACCEPT_ALL:
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RNS.Resource.accept(packet, self.callbacks.resource_concluded)
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elif packet.context == RNS.Packet.LRRTT:
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if not self.initiator:
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self.rtt_packet(packet)
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elif packet.context == RNS.Packet.RESOURCE_REQ:
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plaintext = self.decrypt(packet.data)
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if ord(plaintext[:1]) == RNS.Resource.HASHMAP_IS_EXHAUSTED:
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resource_hash = plaintext[1+RNS.Resource.MAPHASH_LEN:RNS.Identity.HASHLENGTH/8+1+RNS.Resource.MAPHASH_LEN]
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else:
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resource_hash = plaintext[1:RNS.Identity.HASHLENGTH/8+1]
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for resource in self.outgoing_resources:
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if resource.hash == resource_hash:
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resource.request(plaintext)
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elif packet.context == RNS.Packet.LINKCLOSE:
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self.teardown_packet(packet)
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elif packet.context == RNS.Packet.RESOURCE_HMU:
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plaintext = self.decrypt(packet.data)
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resource_hash = plaintext[:RNS.Identity.HASHLENGTH/8]
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for resource in self.incoming_resources:
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if resource_hash == resource.hash:
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resource.hashmap_update_packet(plaintext)
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elif packet.context == RNS.Packet.RESOURCE_ADV:
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packet.plaintext = self.decrypt(packet.data)
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if self.resource_strategy == Link.ACCEPT_NONE:
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pass
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elif self.resource_strategy == Link.ACCEPT_APP:
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if self.callbacks.resource != None:
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self.callbacks.resource(packet)
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elif self.resource_strategy == Link.ACCEPT_ALL:
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RNS.Resource.accept(packet, self.callbacks.resource_concluded)
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elif packet.context == RNS.Packet.RESOURCE_ICL:
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plaintext = self.decrypt(packet.data)
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resource_hash = plaintext[:RNS.Identity.HASHLENGTH/8]
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for resource in self.incoming_resources:
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if resource_hash == resource.hash:
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resource.cancel()
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elif packet.context == RNS.Packet.RESOURCE_REQ:
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plaintext = self.decrypt(packet.data)
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if ord(plaintext[:1]) == RNS.Resource.HASHMAP_IS_EXHAUSTED:
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resource_hash = plaintext[1+RNS.Resource.MAPHASH_LEN:RNS.Identity.HASHLENGTH/8+1+RNS.Resource.MAPHASH_LEN]
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else:
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resource_hash = plaintext[1:RNS.Identity.HASHLENGTH/8+1]
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for resource in self.outgoing_resources:
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if resource.hash == resource_hash:
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resource.request(plaintext)
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# TODO: find the most efficient way to allow multiple
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# transfers at the same time, sending resource hash on
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# each packet is a huge overhead
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elif packet.context == RNS.Packet.RESOURCE:
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for resource in self.incoming_resources:
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resource.receive_part(packet)
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elif packet.context == RNS.Packet.RESOURCE_HMU:
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plaintext = self.decrypt(packet.data)
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resource_hash = plaintext[:RNS.Identity.HASHLENGTH/8]
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for resource in self.incoming_resources:
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if resource_hash == resource.hash:
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resource.hashmap_update_packet(plaintext)
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elif packet.packet_type == RNS.Packet.PROOF:
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if packet.context == RNS.Packet.RESOURCE_PRF:
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resource_hash = packet.data[0:RNS.Identity.HASHLENGTH/8]
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for resource in self.outgoing_resources:
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if resource_hash == resource.hash:
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resource.validateProof(packet.data)
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elif packet.context == RNS.Packet.RESOURCE_ICL:
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plaintext = self.decrypt(packet.data)
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resource_hash = plaintext[:RNS.Identity.HASHLENGTH/8]
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for resource in self.incoming_resources:
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if resource_hash == resource.hash:
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resource.cancel()
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# TODO: find the most efficient way to allow multiple
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# transfers at the same time, sending resource hash on
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# each packet is a huge overhead. Probably some kind
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# of hash -> sequence map
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elif packet.context == RNS.Packet.RESOURCE:
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for resource in self.incoming_resources:
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resource.receive_part(packet)
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elif packet.packet_type == RNS.Packet.PROOF:
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if packet.context == RNS.Packet.RESOURCE_PRF:
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resource_hash = packet.data[0:RNS.Identity.HASHLENGTH/8]
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for resource in self.outgoing_resources:
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if resource_hash == resource.hash:
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resource.validateProof(packet.data)
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def encrypt(self, plaintext):
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@ -229,6 +299,9 @@ class Link:
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def link_established_callback(self, callback):
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self.callbacks.link_established = callback
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def link_closed_callback(self, callback):
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self.callbacks.link_closed = callback
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def packet_callback(self, callback):
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self.callbacks.packet = callback
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@ -29,6 +29,8 @@ class Packet:
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RESPONSE = 0x09
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COMMAND = 0x0A
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COMMAND_STAT = 0x0B
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LINKCLOSE = 0xFD
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LRRTT = 0xFE
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LRPROOF = 0xFF
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HEADER_MAXSIZE = 23
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@ -143,6 +145,9 @@ class Packet:
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def send(self):
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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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if not self.packed:
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self.pack()
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@ -74,6 +74,8 @@ class Transport:
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if interface.OUT:
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should_transmit = True
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if packet.destination.type == RNS.Destination.LINK:
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if packet.destination.status == RNS.Link.CLOSED:
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should_transmit = False
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if interface != packet.destination.attached_interface:
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should_transmit = False
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