broadcasting and listening to the '_snappy' topics as well

beacon_chain/eth2_network.nim

@@ -5,7 +5,7 @@ import
 
   # Status libs
   stew/[varints, base58, bitseqs], stew/shims/[macros, tables], stint,
-  faststreams/output_stream, snappy/framing,
+  faststreams/output_stream, snappy, snappy/framing,
   json_serialization, json_serialization/std/[net, options],
   chronos, chronicles, metrics,
   # TODO: create simpler to use libp2p modules that use re-exports
@@ -1027,6 +1027,9 @@ proc subscribe*[MsgType](node: Eth2Node,
     trace "Incoming pubsub message received",
       peer = peerExpr, len = gossipBytes.len, topic = gossipTopic,
       message_id = `$`(sha256.digest(gossipBytes))
+    if gossipTopic.endsWith("_snappy"):
+      msgHandler SSZ.decode(snappy.decode(gossipBytes), MsgType)
+    else:
       msgHandler SSZ.decode(gossipBytes, MsgType)
 
   # All message types which are subscribed to should be validated; putting
@@ -1035,6 +1038,9 @@ proc subscribe*[MsgType](node: Eth2Node,
     trace "Incoming pubsub message received for validation",
       len = gossipBytes.len, topic = gossipTopic,
       message_id = `$`(sha256.digest(gossipBytes))
+    if gossipTopic.endsWith("_snappy"):
+      msgValidator SSZ.decode(snappy.decode(gossipBytes), MsgType)
+    else:
       msgValidator SSZ.decode(gossipBytes, MsgType)
 
   # Validate messages as soon as subscribed
@@ -1044,12 +1050,17 @@ proc subscribe*[MsgType](node: Eth2Node,
     return execMsgValidator(message.data, topic)
 
   node.switch.addValidator(topic, incomingMsgValidator)
+  node.switch.addValidator(topic & "_snappy", incomingMsgValidator)
 
   let incomingMsgHandler = proc(topic: string,
                                 data: seq[byte]) {.async, gcsafe.} =
     execMsgHandler "unknown", data, topic
 
-  await node.switch.subscribe(topic, incomingMsgHandler)
+  var switchSubscriptions: seq[Future[void]] = @[]
+  switchSubscriptions.add(node.switch.subscribe(topic, incomingMsgHandler))
+  switchSubscriptions.add(node.switch.subscribe(topic & "_snappy", incomingMsgHandler))
+  
+  waitFor allFutures(switchSubscriptions)
 
 proc traceMessage(fut: FutureBase, digest: MDigest[256]) =
   fut.addCallback do (arg: pointer):
@@ -1062,6 +1073,11 @@ proc broadcast*(node: Eth2Node, topic: string, msg: auto) =
   var fut = node.switch.publish(topic, broadcastBytes)
   traceMessage(fut, sha256.digest(broadcastBytes))
   traceAsyncErrors(fut)
+  # also publish to the snappy-compressed topics
+  let snappy_encoded = snappy.encode(broadcastBytes)
+  var fut_snappy = node.switch.publish(topic & "_snappy", snappy_encoded)
+  traceMessage(fut_snappy, sha256.digest(snappy_encoded))
+  traceAsyncErrors(fut_snappy)
 
 # TODO:
 # At the moment, this is just a compatiblity shim for the existing RLPx functionality.