From 0d2ae7b73f841833fe76521f1f38fc4c5192db34 Mon Sep 17 00:00:00 2001
From: Jeromy <jeromyj@gmail.com>
Date: Wed, 6 Apr 2016 18:41:59 -0700
Subject: [PATCH] don't break listener on failed msmux negotiation

---
 p2p/net/conn/dial_test.go | 48 +++++++++++++++++++++++++++++++++++++++
 p2p/net/conn/listen.go    |  3 ++-
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/p2p/net/conn/dial_test.go b/p2p/net/conn/dial_test.go
index c91fd5b..2179cbd 100644
--- a/p2p/net/conn/dial_test.go
+++ b/p2p/net/conn/dial_test.go
@@ -1,6 +1,7 @@
 package conn
 
 import (
+	"bytes"
 	"fmt"
 	"io"
 	"net"
@@ -349,3 +350,50 @@ func TestMultistreamHeader(t *testing.T) {
 		t.Fatal(err)
 	}
 }
+
+func TestFailedAccept(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	p1 := tu.RandPeerNetParamsOrFatal(t)
+
+	l1, err := Listen(ctx, p1.Addr, p1.ID, p1.PrivKey)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	p1.Addr = l1.Multiaddr() // Addr has been determined by kernel.
+
+	done := make(chan struct{})
+	go func() {
+		defer close(done)
+		con, err := net.Dial("tcp", l1.Addr().String())
+		if err != nil {
+			t.Error("first dial failed: ", err)
+		}
+
+		// write some garbage
+		con.Write(bytes.Repeat([]byte{255}, 1000))
+
+		con.Close()
+
+		con, err = net.Dial("tcp", l1.Addr().String())
+		if err != nil {
+			t.Error("second dial failed: ", err)
+		}
+		defer con.Close()
+
+		err = msmux.SelectProtoOrFail(SecioTag, con)
+		if err != nil {
+			t.Error("msmux select failed: ", err)
+		}
+	}()
+
+	c, err := l1.Accept()
+	if err != nil {
+		t.Fatal("connections after a failed accept should still work: ", err)
+	}
+
+	c.Close()
+	<-done
+}
diff --git a/p2p/net/conn/listen.go b/p2p/net/conn/listen.go
index 33b0975..3d81cba 100644
--- a/p2p/net/conn/listen.go
+++ b/p2p/net/conn/listen.go
@@ -106,7 +106,8 @@ func (l *listener) Accept() (net.Conn, error) {
 
 		_, _, err = l.mux.Negotiate(maconn)
 		if err != nil {
-			return nil, err
+			log.Info("negotiation of crypto protocol failed: ", err)
+			continue
 		}
 
 		c, err := newSingleConn(ctx, l.local, "", maconn)
-- 
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