From: Matt Joiner <anacrolix@gmail.com>
Date: Wed, 13 Jun 2018 00:53:11 +0000 (+1000)
Subject: Allow adding duplicate connections
X-Git-Tag: v1.0.0~127^2~31
X-Git-Url: http://www.git.stargrave.org/?a=commitdiff_plain;h=90f84bda71fbbccec7fb05d69d948cb937d014e4;p=btrtrc.git

Allow adding duplicate connections

I believe this fixes a long-standing race condition when dropping connections to the same peer ID where Clients assume the peer has added connections in the same order. Further commits may address duplicate connections further.
---

diff --git a/torrent.go b/torrent.go
index 91f72da8..2bb5f20b 100644
--- a/torrent.go
+++ b/torrent.go
@@ -1500,25 +1500,6 @@ func (t *Torrent) addConnection(c *connection) error {
 	if !t.wantConns() {
 		return errors.New("don't want conns")
 	}
-	for c0 := range t.conns {
-		if c.PeerID != c0.PeerID {
-			continue
-		}
-		// Already connected to a client with that ID.
-		preferOutbound := string(t.cl.peerID[:]) < string(c.PeerID[:])
-		// Retain the connection from initiated from lower peer ID to higher.
-		if c0.outgoing == preferOutbound {
-			return errors.New("existing connection preferred")
-		}
-		if c.outgoing != preferOutbound {
-			return errors.New("prefer older connection")
-		}
-		// Close the other one.
-		c0.Close()
-		// TODO: Is it safe to delete from the map while we're iterating
-		// over it?
-		t.deleteConnection(c0)
-	}
 	if len(t.conns) >= t.maxEstablishedConns {
 		c := t.worstBadConn()
 		if t.cl.config.Debug && missinggo.CryHeard() {