Implemented dandelion stemout stream building

src/gossip/client/dandelionstem.py

@@ -1,16 +1,16 @@
 from queue import Queue
-from threading import Thread, Timer
 from time import sleep
 from secrets import choice
 import traceback
+from asyncio import wait_for
 
-from typing import TYPE_CHECKING, Tuple, List, Set
+from typing import TYPE_CHECKING, Coroutine, Tuple, List
 
 from onionrthreads import add_delayed_thread
 from blockdb import add_block_to_db
 import logger
 
-from ..constants import BLACKHOLE_EVADE_TIMER_SECS, MAX_OUTBOUND_DANDELION_EDGE
+from ..constants import BLACKHOLE_EVADE_TIMER_SECS, OUTBOUND_DANDELION_EDGES
 from ..commands import GossipCommands, command_to_byte
 from .. import dandelion
 
@@ -33,11 +33,20 @@ async def _setup_edge(
         peer: 'Peer' = choice(peer_set - exclude_set)
     except IndexError:
         raise NotEnoughEdges
+
+    async def _get_sock():
+        return peer.get_socket()
+
+    # If peer is good or bad, exclude it no matter what
+    exclude_set.add(peer)
+
     try:
-        s = peer.get_socket()
+        s = await wait_for(_get_sock(), 12)
+    except TimeoutError:
+        logger.debug(f"{peer.transport_address} timed out when trying stemout")
     except Exception:
         logger.debug(traceback.format_exc())
-        exclude_set.add(peer)
+        return
 
     try:
         s.sendall(command_to_byte(GossipCommands.PUT_BLOCKS))
@@ -54,9 +63,7 @@ async def _setup_edge(
     else:
         # Return peer socket if it is in stem reception mode successfully
         return s
-    finally:
+
-        # If peer is good or bad, exclude it no matter what
-        exclude_set.add(peer)
     # If they won't accept stem blocks, close the socket
     s.close()
 
@@ -73,7 +80,6 @@ async def stem_out(
         peer_set: OrderedSet['Peer'],
         d_phase: 'DandelionPhase'):
 
-
     # don't bother if there are no possible outbound edges
     if not len(peer_set):
         sleep(1)
@@ -87,22 +93,49 @@ async def stem_out(
             BLACKHOLE_EVADE_TIMER_SECS, list(block_q.queue))
 
     peer_sockets: List['socket.socket'] = []
+    stream_routines: List[Coroutine] = []
 
     # Pick edges randomly
     # Using orderedset for the tried edges to ensure random pairing with queue
     tried_edges: OrderedSet['Peer'] = OrderedSet()
 
-    while len(peer_sockets) < MAX_OUTBOUND_DANDELION_EDGE:
+    while len(peer_sockets) < OUTBOUND_DANDELION_EDGES:
         try:
-            peer_sockets.append(_setup_edge(peer_set, tried_edges))
+            # Get a socket for stem out (makes sure they accept)
+            peer_sockets.append(
+                await wait_for(_setup_edge(peer_set, tried_edges), 15))
         except NotEnoughEdges:
-            logger.debug("Not able to build enough peers for stemout")
+            # No possible edges at this point (edges < OUTBOUND_DANDELION_EDGE)
+            logger.warn("Not able to build enough peers for stemout.", terminal=True)
             break
-        finally:
+        else:
+            # Ran out of time for stem phase
             if not d_phase.is_stem_phase() or d_phase.remaining_time() < 5:
                 logger.error(
                     "Did not stem out any blocks in time, " +
                     "if this happens regularly you may be under attack",
                     terminal=True)
+                list(map(lambda p: p.close(), peer_sockets))
+                peer_sockets.clear()
+                break
+    # If above loop ran out of time or NotEnoughEdges, loops below will not execute
 
+    for count, peer_socket in enumerate(peer_sockets):
+        stream_routines.append(
+            _do_stem_stream(peer_socket, block_queues[count], d_phase))
 
+    for routine in stream_routines:
+        try:
+            await wait_for(routine, d_phase.remaining_time() + 1)
+        except TimeoutError:
+            # This is what should happen if everything went well
+            pass
+        except Exception:
+            logger.warn(traceback.format_exc())
+        else:
+            # stream routine exited early
+            pass
+
+    # Clean up stem sockets
+    for sock in peer_sockets:
+        sock.close()

src/gossip/constants.py

@@ -3,13 +3,13 @@ PEER_AMOUNT_TO_ASK = 3
 TRANSPORT_SIZE_BYTES = 64
 BLOCK_MAX_SIZE = 1024 * 2000
 BLOCK_ID_SIZE = 128
-DANDELION_EPOCH_LENGTH = 60
+DANDELION_EPOCH_LENGTH = 120
 
 # Magic number i made up, not really specified in dandelion++ paper
 MAX_INBOUND_DANDELION_EDGE = 50  # Mainly picked to avoid slowloris
 
 # Dandelion subgraph is aprox 4-regular
-MAX_OUTBOUND_DANDELION_EDGE = 2
+OUTBOUND_DANDELION_EDGES = 2
 
 MAX_STEM_BLOCKS_PER_STREAM = 1000
 BLACKHOLE_EVADE_TIMER_SECS = DANDELION_EPOCH_LENGTH * 3

static-data/default-plugins/tor/torpeer.py

@@ -13,6 +13,7 @@ class TorPeer:
     def get_socket(self) -> socks.socksocket:
         s = socks.socksocket()
         s.set_proxy(socks.SOCKS4, self.socks_host, self.socks_port, rdns=True)
+        s.settimeout(60)
         s.connect((self.onion_address, 80))
         return s