Optimised link establishment

README.md

@@ -33,7 +33,7 @@ For more info, see [unsigned.io/projects/reticulum](https://unsigned.io/projects
     - Sequencing, transfer coordination and checksumming is automatic
     - The API is very easy to use, and provides transfer progress
  - Efficient link establishment
-    - Total bandwidth cost of setting up a link is 3 packets totalling 409 bytes
+    - Total bandwidth cost of setting up a link is 3 packets totalling 240 bytes
     - Low cost of keeping links open at only 0.62 bits per second
 
 ## Where can Reticulum be used?

RNS/Destination.py

@@ -209,11 +209,12 @@ class Destination:
             self.proof_strategy = proof_strategy
 
     def receive(self, packet):
+        if packet.packet_type == RNS.Packet.LINKREQUEST:
+            plaintext = packet.data
+            self.incoming_link_request(plaintext, packet)
+        else:
             plaintext = self.decrypt(packet.data)
             if plaintext != None:
-            if packet.packet_type == RNS.Packet.LINKREQUEST:
-                self.incoming_link_request(plaintext, packet)
-
                 if packet.packet_type == RNS.Packet.DATA:
                     if self.callbacks.packet != None:
                         self.callbacks.packet(plaintext, packet)

RNS/Link.py

@@ -52,7 +52,7 @@ class Link:
     """
     TIMEOUT_FACTOR = 3
     STALE_GRACE = 2
-    KEEPALIVE = 180
+    KEEPALIVE = 360
     """
     Interval for sending keep-alive packets on established links in seconds.
     """
@@ -128,14 +128,15 @@ class Link:
         self.__encryption_disabled = False
         if self.destination == None:
             self.initiator = False
+            self.prv     = self.owner.identity.prv
+            self.sig_prv = self.owner.identity.sig_prv
         else:
             self.initiator = True
-
-        self.fernet  = None
-        
             self.prv     = X25519PrivateKey.generate()
             self.sig_prv = Ed25519PrivateKey.generate()
 
+        self.fernet  = None
+        
         self.pub = self.prv.public_key()
         self.pub_bytes = self.pub.public_bytes(
             encoding=serialization.Encoding.Raw,
@@ -155,10 +156,14 @@ class Link:
             self.load_peer(peer_pub_bytes, peer_sig_pub_bytes)
 
         if (self.initiator):
+            peer_pub_bytes = self.destination.identity.get_public_key()[:Link.ECPUBSIZE//2]
+            peer_sig_pub_bytes = self.destination.identity.get_public_key()[Link.ECPUBSIZE//2:Link.ECPUBSIZE]
             self.request_data = self.pub_bytes+self.sig_pub_bytes
             self.packet = RNS.Packet(destination, self.request_data, packet_type=RNS.Packet.LINKREQUEST)
             self.packet.pack()
             self.set_link_id(self.packet)
+            self.load_peer(peer_pub_bytes, peer_sig_pub_bytes)
+            self.handshake()
             RNS.Transport.register_link(self)
             self.request_time = time.time()
             self.start_watchdog()
@@ -195,7 +200,7 @@ class Link:
         signed_data = self.link_id+self.pub_bytes+self.sig_pub_bytes
         signature = self.owner.identity.sign(signed_data)
 
-        proof_data = self.pub_bytes+self.sig_pub_bytes+signature
+        proof_data = signature
         proof = RNS.Packet(self, proof_data, packet_type=RNS.Packet.PROOF, context=RNS.Packet.LRPROOF)
         proof.send()
         self.had_outbound()
@@ -214,15 +219,11 @@ class Link:
         self.had_outbound()
 
     def validate_proof(self, packet):
-        if self.initiator and len(packet.data) == Link.ECPUBSIZE+RNS.Identity.KEYSIZE//8:
+        if self.initiator and len(packet.data) == RNS.Identity.SIGLENGTH//8:
-            peer_pub_bytes = packet.data[:Link.ECPUBSIZE//2]
+            signed_data = self.link_id+self.peer_pub_bytes+self.peer_sig_pub_bytes
-            peer_sig_pub_bytes = packet.data[Link.ECPUBSIZE//2:Link.ECPUBSIZE]
+            signature = packet.data[:RNS.Identity.SIGLENGTH//8]
-            signed_data = self.link_id+peer_pub_bytes+peer_sig_pub_bytes
-            signature = packet.data[Link.ECPUBSIZE:RNS.Identity.KEYSIZE//8+Link.ECPUBSIZE]
             
             if self.destination.identity.validate(signature, signed_data):
-                self.load_peer(peer_pub_bytes, peer_sig_pub_bytes)
-                self.handshake()
                 self.rtt = time.time() - self.request_time
                 self.attached_interface = packet.receiving_interface
                 RNS.Transport.activate_link(self)
@@ -258,8 +259,7 @@ class Link:
             if self.owner.callbacks.link_established != None:
                     self.owner.callbacks.link_established(self)
         except Exception as e:
-            RNS.log("Error occurred while processing RTT packet, tearing down link", RNS.LOG_ERROR)
+            RNS.log("Error occurred while processing RTT packet, tearing down link. The contained exception was: "+str(e), RNS.LOG_ERROR)
-            traceback.print_exc()
             self.teardown()
 
     def get_salt(self):

RNS/Packet.py

@@ -143,6 +143,9 @@ class Packet:
                 if self.packet_type == Packet.ANNOUNCE:
                     # Announce packets are not encrypted
                     self.ciphertext = self.data
+                elif self.packet_type == Packet.LINKREQUEST:
+                    # Link request 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

docs/manual/_sources/understanding.rst.txt

@@ -429,7 +429,7 @@ terms of bandwidth, so it can be used just for a short exchange, and then recrea
 also rotate encryption keys. The link can also be kept alive for longer periods of time, if this is
 more suitable to the application. The procedure also inserts the *link id* , a hash calculated from the link request packet, into the memory of forwarding nodes, which means that the communicating nodes can thereafter reach each other simply by referring to this *link id*.
 
-The combined bandwidth cost of setting up a link is 3 packets totalling 409 bytes (more info in the
+The combined bandwidth cost of setting up a link is 3 packets totalling 240 bytes (more info in the
 :ref:`Binary Packet Format<understanding-packetformat>` section). The amount of bandwidth used on keeping
 a link open is practically negligible, at 0.62 bits per second. Even on a slow 1200 bits per second packet
 radio channel, 100 concurrent links will still leave 95% channel capacity for actual data.
@@ -699,7 +699,7 @@ Binary Packet Format
 
      - Path Request    :    33  bytes
      - Announce        :    151 bytes
-     - Link Request    :    182 bytes
+     - Link Request    :    77  bytes
-     - Link Proof      :    141 bytes
+     - Link Proof      :    77  bytes
      - Link RTT packet :    86  bytes
      - Link keepalive  :    14  bytes

docs/manual/_sources/whatis.rst.txt

@@ -55,7 +55,7 @@ What does Reticulum Offer?
 
 * Efficient link establishment
 
-  * Total bandwidth cost of setting up a link is only 409 bytes
+  * Total bandwidth cost of setting up a link is only 3 packets, totalling 240 bytes
 
   * Low cost of keeping links open at only 0.62 bits per second
 

docs/manual/reference.html

@@ -767,7 +767,7 @@ from a the <em>send()</em> method of a <a class="reference internal" href="#api-
 
 <dl class="py attribute">
 <dt class="sig sig-object py" id="RNS.Link.KEEPALIVE">
-<span class="sig-name descname"><span class="pre">KEEPALIVE</span></span><em class="property"> <span class="pre">=</span> <span class="pre">180</span></em><a class="headerlink" href="#RNS.Link.KEEPALIVE" title="Permalink to this definition">¶</a></dt>
+<span class="sig-name descname"><span class="pre">KEEPALIVE</span></span><em class="property"> <span class="pre">=</span> <span class="pre">360</span></em><a class="headerlink" href="#RNS.Link.KEEPALIVE" title="Permalink to this definition">¶</a></dt>
 <dd><p>Interval for sending keep-alive packets on established links in seconds.</p>
 </dd></dl>
 

docs/manual/understanding.html

@@ -490,7 +490,7 @@ At the same time we establish an efficient encrypted channel. The setup of this
 terms of bandwidth, so it can be used just for a short exchange, and then recreated as needed, which will
 also rotate encryption keys. The link can also be kept alive for longer periods of time, if this is
 more suitable to the application. The procedure also inserts the <em>link id</em> , a hash calculated from the link request packet, into the memory of forwarding nodes, which means that the communicating nodes can thereafter reach each other simply by referring to this <em>link id</em>.</p>
-<p>The combined bandwidth cost of setting up a link is 3 packets totalling 409 bytes (more info in the
+<p>The combined bandwidth cost of setting up a link is 3 packets totalling 240 bytes (more info in the
 <a class="reference internal" href="#understanding-packetformat"><span class="std std-ref">Binary Packet Format</span></a> section). The amount of bandwidth used on keeping
 a link open is practically negligible, at 0.62 bits per second. Even on a slow 1200 bits per second packet
 radio channel, 100 concurrent links will still leave 95% channel capacity for actual data.</p>
@@ -762,8 +762,8 @@ proof           11
 
  - Path Request    :    33  bytes
  - Announce        :    151 bytes
- - Link Request    :    182 bytes
+ - Link Request    :    77  bytes
- - Link Proof      :    141 bytes
+ - Link Proof      :    77  bytes
  - Link RTT packet :    86  bytes
  - Link keepalive  :    14  bytes
 </pre></div>

docs/manual/whatis.html

@@ -81,7 +81,7 @@
 </li>
 <li><p>Efficient link establishment</p>
 <ul>
-<li><p>Total bandwidth cost of setting up a link is only 409 bytes</p></li>
+<li><p>Total bandwidth cost of setting up a link is only 3 packets, totalling 240 bytes</p></li>
 <li><p>Low cost of keeping links open at only 0.62 bits per second</p></li>
 </ul>
 </li>

docs/source/understanding.rst

@@ -429,7 +429,7 @@ terms of bandwidth, so it can be used just for a short exchange, and then recrea
 also rotate encryption keys. The link can also be kept alive for longer periods of time, if this is
 more suitable to the application. The procedure also inserts the *link id* , a hash calculated from the link request packet, into the memory of forwarding nodes, which means that the communicating nodes can thereafter reach each other simply by referring to this *link id*.
 
-The combined bandwidth cost of setting up a link is 3 packets totalling 409 bytes (more info in the
+The combined bandwidth cost of setting up a link is 3 packets totalling 240 bytes (more info in the
 :ref:`Binary Packet Format<understanding-packetformat>` section). The amount of bandwidth used on keeping
 a link open is practically negligible, at 0.62 bits per second. Even on a slow 1200 bits per second packet
 radio channel, 100 concurrent links will still leave 95% channel capacity for actual data.
@@ -699,7 +699,7 @@ Binary Packet Format
 
      - Path Request    :    33  bytes
      - Announce        :    151 bytes
-     - Link Request    :    182 bytes
+     - Link Request    :    77  bytes
-     - Link Proof      :    141 bytes
+     - Link Proof      :    77  bytes
      - Link RTT packet :    86  bytes
      - Link keepalive  :    14  bytes

docs/source/whatis.rst

@@ -55,7 +55,7 @@ What does Reticulum Offer?
 
 * Efficient link establishment
 
-  * Total bandwidth cost of setting up a link is only 409 bytes
+  * Total bandwidth cost of setting up a link is only 3 packets, totalling 240 bytes
 
   * Low cost of keeping links open at only 0.62 bits per second