From 9e922bde5896c990ff89f5deaeb7512c34bf7dd2 Mon Sep 17 00:00:00 2001
From: Mahak Mukhi <mmukhi@google.com>
Date: Fri, 10 Feb 2017 11:41:20 -0800
Subject: [PATCH] Issue #1060 maximum number of streams on the client should be
 capped at 100 by default

---
 test/end2end_test.go      | 39 +++++++++++++++++++++++++++++++++++++++
 transport/control.go      |  5 +++--
 transport/http2_client.go |  2 +-
 3 files changed, 43 insertions(+), 3 deletions(-)

diff --git a/test/end2end_test.go b/test/end2end_test.go
index 902bec42..0ba0256f 100644
--- a/test/end2end_test.go
+++ b/test/end2end_test.go
@@ -2671,6 +2671,45 @@ func testExceedMaxStreamsLimit(t *testing.T, e env) {
 	}
 }
 
+const defaultMaxStreamsClient = 100
+
+func TestClientExceedMaxStreamsLimit(t *testing.T) {
+	defer leakCheck(t)()
+	for _, e := range listTestEnv() {
+		testExceedMaxStreamsLimit(t, e)
+	}
+}
+
+func testClientExceedMaxStreamsLimit(t *testing.T, e env) {
+	te := newTest(t, e)
+	te.declareLogNoise(
+		"http2Client.notifyError got notified that the client transport was broken",
+		"Conn.resetTransport failed to create client transport",
+		"grpc: the connection is closing",
+	)
+	te.maxStream = 0 // Server allows infinite streams. The cap should be on client side.
+	te.startServer(&testServer{security: e.security})
+	defer te.tearDown()
+
+	cc := te.clientConn()
+	tc := testpb.NewTestServiceClient(cc)
+
+	// Create as many streams as a client can.
+	for i := 0; i < defaultMaxStreamsClient; i++ {
+		if _, err := tc.StreamingInputCall(te.ctx); err != nil {
+			t.Fatalf("%v.StreamingInputCall(_) = _, %v, want _, <nil>", tc, err)
+		}
+	}
+
+	// Trying to create one more should timeout.
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	defer cancel()
+	_, err := tc.StreamingInputCall(ctx)
+	if err == nil || grpc.Code(err) != codes.DeadlineExceeded {
+		t.Fatalf("%v.StreamingInputCall(_) = _, %v, want _, %s", tc, err, codes.DeadlineExceeded)
+	}
+}
+
 func TestStreamsQuotaRecovery(t *testing.T) {
 	defer leakCheck(t)()
 	for _, e := range listTestEnv() {
diff --git a/transport/control.go b/transport/control.go
index 2586cba4..33de7b60 100644
--- a/transport/control.go
+++ b/transport/control.go
@@ -44,8 +44,9 @@ const (
 	// The default value of flow control window size in HTTP2 spec.
 	defaultWindowSize = 65535
 	// The initial window size for flow control.
-	initialWindowSize     = defaultWindowSize      // for an RPC
-	initialConnWindowSize = defaultWindowSize * 16 // for a connection
+	initialWindowSize       = defaultWindowSize      // for an RPC
+	initialConnWindowSize   = defaultWindowSize * 16 // for a connection
+	defaultMaxStreamsClient = 100
 )
 
 // The following defines various control items which could flow through
diff --git a/transport/http2_client.go b/transport/http2_client.go
index 892f8ba6..a85552be 100644
--- a/transport/http2_client.go
+++ b/transport/http2_client.go
@@ -208,7 +208,7 @@ func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions) (
 		state:           reachable,
 		activeStreams:   make(map[uint32]*Stream),
 		creds:           opts.PerRPCCredentials,
-		maxStreams:      math.MaxInt32,
+		maxStreams:      defaultMaxStreamsClient,
 		streamSendQuota: defaultWindowSize,
 		statsHandler:    opts.StatsHandler,
 	}