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-rw-r--r--p2p/server.go20
1 files changed, 19 insertions, 1 deletions
diff --git a/p2p/server.go b/p2p/server.go
index 7b880f77b..5cd3dc2ad 100644
--- a/p2p/server.go
+++ b/p2p/server.go
@@ -21,6 +21,11 @@ const (
defaultDialTimeout = 10 * time.Second
refreshPeersInterval = 30 * time.Second
+ // This is the maximum number of inbound connection
+ // that are allowed to linger between 'accepted' and
+ // 'added as peer'.
+ maxAcceptConns = 50
+
// total timeout for encryption handshake and protocol
// handshake in both directions.
handshakeTimeout = 5 * time.Second
@@ -269,15 +274,28 @@ func (srv *Server) Self() *discover.Node {
// main loop for adding connections via listening
func (srv *Server) listenLoop() {
defer srv.loopWG.Done()
+
+ // This channel acts as a semaphore limiting
+ // active inbound connections that are lingering pre-handshake.
+ // If all slots are taken, no further connections are accepted.
+ slots := make(chan struct{}, maxAcceptConns)
+ for i := 0; i < maxAcceptConns; i++ {
+ slots <- struct{}{}
+ }
+
glog.V(logger.Info).Infoln("Listening on", srv.listener.Addr())
for {
+ <-slots
conn, err := srv.listener.Accept()
if err != nil {
return
}
glog.V(logger.Debug).Infof("Accepted conn %v\n", conn.RemoteAddr())
srv.peerWG.Add(1)
- go srv.startPeer(conn, nil)
+ go func() {
+ srv.startPeer(conn, nil)
+ slots <- struct{}{}
+ }()
}
}