From 76324844a9f23bdcf88e0537fcbf895b1add7e9c Mon Sep 17 00:00:00 2001
From: Ivan Kozlovic <ivan.kozlovic@apcera.com>
Date: Wed, 23 Mar 2016 14:26:06 -0700
Subject: [PATCH] Fixed handling of unprompted PONG protocols

- The number of outstanding PINGs is now reset whenever the server
receives a PONG from the client.
- Updated parser test to check c.pout.
- Added a test to check for unprompted PONGs.

Resolves issue: https://github.com/nats-io/gnatsd/issues/168
---
 server/client.go      |  2 +-
 server/parser_test.go | 15 +++++++++++---
 test/ping_test.go     | 46 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 59 insertions(+), 4 deletions(-)

diff --git a/server/client.go b/server/client.go
index f3d9eefb..8a90194c 100644
--- a/server/client.go
+++ b/server/client.go
@@ -356,7 +356,7 @@ func (c *client) processPing() {
 func (c *client) processPong() {
 	c.traceInOp("PONG", nil)
 	c.mu.Lock()
-	c.pout--
+	c.pout = 0
 	c.mu.Unlock()
 }
 
diff --git a/server/parser_test.go b/server/parser_test.go
index 06696b8e..63d0403a 100644
--- a/server/parser_test.go
+++ b/server/parser_test.go
@@ -93,10 +93,16 @@ func TestParsePong(t *testing.T) {
 	if err != nil || c.state != OP_START {
 		t.Fatalf("Unexpected: %d : %v\n", c.state, err)
 	}
+	if c.pout != 0 {
+		t.Fatalf("Unexpected pout value: %d vs 0\n", c.pout)
+	}
 	err = c.parse(pong)
 	if err != nil || c.state != OP_START {
 		t.Fatalf("Unexpected: %d : %v\n", c.state, err)
 	}
+	if c.pout != 0 {
+		t.Fatalf("Unexpected pout value: %d vs 0\n", c.pout)
+	}
 	// Should tolerate spaces
 	pong = []byte("PONG  \r")
 	err = c.parse(pong)
@@ -109,8 +115,11 @@ func TestParsePong(t *testing.T) {
 	if err != nil || c.state != OP_START {
 		t.Fatalf("Unexpected: %d : %v\n", c.state, err)
 	}
+	if c.pout != 0 {
+		t.Fatalf("Unexpected pout value: %d vs 0\n", c.pout)
+	}
 
-	// Should be adjusting c.pout, Pings Outstanding
+	// Should be adjusting c.pout (Pings Outstanding): reset to 0
 	c.state = OP_START
 	c.pout = 10
 	pong = []byte("PONG\r\n")
@@ -118,8 +127,8 @@ func TestParsePong(t *testing.T) {
 	if err != nil || c.state != OP_START {
 		t.Fatalf("Unexpected: %d : %v\n", c.state, err)
 	}
-	if c.pout != 9 {
-		t.Fatalf("Unexpected pout: %d vs %d\n", c.pout, 9)
+	if c.pout != 0 {
+		t.Fatalf("Unexpected pout: %d vs 0\n", c.pout)
 	}
 }
 
diff --git a/test/ping_test.go b/test/ping_test.go
index a92bcff7..f259b8af 100644
--- a/test/ping_test.go
+++ b/test/ping_test.go
@@ -65,3 +65,49 @@ func TestPingInterval(t *testing.T) {
 		t.Fatal("timeout: Expected to have connection closed")
 	}
 }
+
+func TestUnpromptedPong(t *testing.T) {
+	s := runPingServer()
+	defer s.Shutdown()
+
+	c := createClientConn(t, "localhost", PING_TEST_PORT)
+	defer c.Close()
+
+	doConnect(t, c, false, false, false)
+
+	expect := expectCommand(t, c)
+
+	// Send lots of PONGs in a row...
+	for i := 0; i < 100; i++ {
+		c.Write([]byte("PONG\r\n"))
+	}
+
+	// The server should still send the max number of PINGs and then
+	// close the connection.
+	for i := 0; i < PING_MAX; i++ {
+		time.Sleep(PING_INTERVAL / 2)
+		expect(pingRe)
+	}
+
+	// We should get an error from the server
+	time.Sleep(PING_INTERVAL)
+	expect(errRe)
+
+	// Server should close the connection at this point..
+	c.SetWriteDeadline(time.Now().Add(PING_INTERVAL))
+	var err error
+	for {
+		_, err = c.Write([]byte("PING\r\n"))
+		if err != nil {
+			break
+		}
+	}
+	c.SetWriteDeadline(time.Time{})
+
+	if err == nil {
+		t.Fatal("No error: Expected to have connection closed")
+	}
+	if ne, ok := err.(net.Error); ok && ne.Timeout() {
+		t.Fatal("timeout: Expected to have connection closed")
+	}
+}