From f8292f7086cf7a389ebf269d49537c88f4ba7b01 Mon Sep 17 00:00:00 2001
From: Giovanni Petrantoni <giovanni@fragcolor.xyz>
Date: Tue, 23 Jun 2020 15:56:07 +0900
Subject: [PATCH] explicit peering part 2

---
 libp2p/protocols/pubsub/gossipsub.nim | 15 ++++++++++++++-
 libp2p/switch.nim                     |  5 +++--
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/libp2p/protocols/pubsub/gossipsub.nim b/libp2p/protocols/pubsub/gossipsub.nim
index 4982723d1..eb46b1f96 100644
--- a/libp2p/protocols/pubsub/gossipsub.nim
+++ b/libp2p/protocols/pubsub/gossipsub.nim
@@ -51,6 +51,8 @@ type
     mesh*: Table[string, HashSet[string]]      # meshes - topic to peer
     fanout*: Table[string, HashSet[string]]    # fanout - topic to peer
     gossipsub*: Table[string, HashSet[string]] # topic to peer map of all gossipsub peers
+    explicit*: Table[string, HashSet[string]] # # topic to peer map of all explicit peers
+    explicitPeers*: HashSet[string] # explicit (always connected/forward) peers
     lastFanoutPubSub*: Table[string, Moment]   # last publish time for fanout topics
     gossip*: Table[string, seq[ControlIHave]]  # pending gossip
     control*: Table[string, ControlMessage]    # pending control messages
@@ -70,6 +72,9 @@ method init*(g: GossipSub) =
     ## e.g. ``/floodsub/1.0.0``, etc...
     ##
 
+    if conn.peerInfo.maintain:
+      g.explicitPeers.incl(conn.peerInfo.id)
+
     await g.handleConn(conn, proto)
 
   g.handler = handler
@@ -288,10 +293,14 @@ method subscribeTopic*(g: GossipSub,
     trace "adding subscription for topic", peer = peerId, name = topic
     # subscribe remote peer to the topic
     g.gossipsub[topic].incl(peerId)
+    if peerId in g.explicit:
+      g.explicit[topic].incl(peerId)
   else:
     trace "removing subscription for topic", peer = peerId, name = topic
     # unsubscribe remote peer from the topic
     g.gossipsub[topic].excl(peerId)
+    if peerId in g.explicit:
+      g.explicit[topic].excl(peerId)
 
   libp2p_gossipsub_peers_per_topic_gossipsub
     .set(g.gossipsub.getOrDefault(topic).len.int64, labelValues = [topic])
@@ -375,7 +384,8 @@ method rpcHandler*(g: GossipSub,
           trace "dropping message due to failed signature verification"
           continue
 
-        if not (await g.validate(msg)):
+        # explicit peers skip validation!
+        if not peer.peerInfo.maintain and not (await g.validate(msg)):
           trace "dropping message due to failed validation"
           continue
 
@@ -392,6 +402,9 @@ method rpcHandler*(g: GossipSub,
           if t in g.mesh:
             toSendPeers.incl(g.mesh[t])            # get all mesh peers for topic
 
+          if t in g.explicit:
+            toSendPeers.incl(g.explicit[t])        # always forward to explicit peers
+
           if t in g.topics:                        # if we're subscribed to the topic
             for h in g.topics[t].handler:
               trace "calling handler for message", msg = msg.msgId,
diff --git a/libp2p/switch.nim b/libp2p/switch.nim
index 848ceff69..7d34ea08c 100644
--- a/libp2p/switch.nim
+++ b/libp2p/switch.nim
@@ -415,8 +415,9 @@ proc maintainPeer(s: Switch, peerInfo: PeerInfo) {.async.} =
     tryAndWarn "explicit peer maintain":
       var conn = s.connections.getOrDefault(peerInfo.id)
       if conn.isNil or conn.closed:
-        # attempt redial in this case
-        discard
+        # attempt re-connect in this case
+        trace "explicit peering, trying to re-connect", peer=peerInfo
+        await s.connect(peerInfo)
     
       await sleepAsync(5.minutes) # spec recommended