Start working on relays being able to talk to each other

relay.py

@@ -10,6 +10,48 @@ import nacl.public
 import network
 import dirauth
 
+class CircuitCellMsg(network.NetMsg):
+    """Send a message tagged with a circuit id."""
+    def __init__(self, circuitid, msg):
+        self.circid = circuitid
+        self.msg = msg
+
+    def __str__(self):
+        return "C%d:%s" % (self.circid, self.msg)
+
+
+class MultiplexedCircuitConnection(network.Connection):
+    """A class representing a connection between a relay and either a
+    client or a relay, transporting cells from various circuits."""
+    def __init__(self):
+        super().__init__()
+        # The CellRelay managing this MultiplexedCircuitConnection
+        self.cellrelay = None
+        # The MultiplexedCircuitConnection at the other end
+        self.peer = None
+        # The function to call when the connection closes
+        self.closer = lambda: 0
+
+    def closed(self):
+        self.closer()
+        self.peer = None
+
+    def close(self):
+        if self.peer is not None:
+            self.peer.closed()
+        self.closed()
+
+    def send_cell(self, circid, msg):
+        """Send the given message, tagged for the given circuit id."""
+        cell = CircuitCellMsg(circid, msg)
+        self.peer.received(self, cell)
+
+    def received(self, peer, cell):
+        """Callback when a cell is received from the network."""
+        circid, msg = cell.circid, cell.msg
+        print("received", msg, "on circuit", circid, "from", peer)
+
+
 class Relay(network.Server):
     """The class representing an onion relay."""
 
@@ -68,6 +110,18 @@ class Relay(network.Server):
             c.sendmsg(descmsg)
             c.close()
 
+    def connected(self, peer):
+        """Callback invoked when someone (client or relay) connects to
+        us.  Create a pair of linked MultiplexedCircuitConnections and
+        return the peer half to the peer."""
+
+        # Create the linked pair
+        peerconn = MultiplexedCircuitConnection()
+        ourconn = MultiplexedCircuitConnection()
+        peerconn.peer = ourconn
+        ourconn.peer = peerconn
+
+        return peerconn
 
 if __name__ == '__main__':
     # Start some dirauths
@@ -79,6 +133,7 @@ if __name__ == '__main__':
 
     # Start some relays
     numrelays = 10
+    relays = []
     for i in range(numrelays):
         # Relay bandwidths (at least the ones fast enough to get used)
         # in the live Tor network (as of Dec 2019) are well approximated
@@ -86,7 +141,7 @@ if __name__ == '__main__':
         # uniform integer in [1,2500]
         x = random.randint(1,2500)
         bw = int(200000-(200000-25000)/3*math.log10(x))
-        Relay(dirauthaddrs, bw, 0)
+        relays.append(Relay(dirauthaddrs, bw, 0))
 
     # Tick the epoch
     network.thenetwork.nextepoch()
@@ -94,3 +149,7 @@ if __name__ == '__main__':
     dirauth.DirAuth.consensus.verify(network.thenetwork.dirauthkeys())
 
     print('ticked; epoch=', network.thenetwork.getepoch())
+
+    c = network.thenetwork.connect(relays[3].netaddr,relays[3].consensus.consdict['relays'][5].descdict['addr'])
+
+    c.send_cell(1, network.StringNetMsg("test"))