[internal-branch.go1.16-vendor] http2: shut down idle Transport connections after protocol errors

Updates golang/go#49076

Change-Id: Ic4e85cdc75b4baef7cd61a65b1b09f430a2ffc4b
Reviewed-on: https://go-review.googlesource.com/c/net/+/352449
Trust: Brad Fitzpatrick <[email protected]>
Run-TryBot: Brad Fitzpatrick <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Damien Neil <[email protected]>
Reviewed-on: https://go-review.googlesource.com/c/net/+/356985
Trust: Damien Neil <[email protected]>
Run-TryBot: Damien Neil <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>

Author: bradfitz

http2/transport.go

@@ -866,6 +866,12 @@ func (cc *ClientConn) closeIfIdle() {
 	cc.tconn.Close()
 }
 
+func (cc *ClientConn) isDoNotReuseAndIdle() bool {
+	cc.mu.Lock()
+	defer cc.mu.Unlock()
+	return cc.doNotReuse && len(cc.streams) == 0
+}
+
 var shutdownEnterWaitStateHook = func() {}
 
 // Shutdown gracefully close the client connection, waiting for running streams to complete.
@@ -2271,6 +2277,9 @@ func (b transportResponseBody) Close() error {
 func (rl *clientConnReadLoop) processData(f *DataFrame) error {
 	cc := rl.cc
 	cs := cc.streamByID(f.StreamID, f.StreamEnded())
+	if f.StreamEnded() && cc.isDoNotReuseAndIdle() {
+		rl.closeWhenIdle = true
+	}
 	data := f.Data()
 	if cs == nil {
 		cc.mu.Lock()
@@ -2517,11 +2526,15 @@ func (rl *clientConnReadLoop) processWindowUpdate(f *WindowUpdateFrame) error {
 }
 
 func (rl *clientConnReadLoop) processResetStream(f *RSTStreamFrame) error {
-	cs := rl.cc.streamByID(f.StreamID, true)
+	cc := rl.cc
+	cs := cc.streamByID(f.StreamID, true)
 	if cs == nil {
 		// TODO: return error if server tries to RST_STEAM an idle stream
 		return nil
 	}
+	if cc.isDoNotReuseAndIdle() {
+		rl.closeWhenIdle = true
+	}
 	select {
 	case <-cs.peerReset:
 		// Already reset.
@@ -2533,9 +2546,7 @@ func (rl *clientConnReadLoop) processResetStream(f *RSTStreamFrame) error {
 		if f.ErrCode == ErrCodeProtocol {
 			rl.cc.SetDoNotReuse()
 			serr.Cause = errFromPeer
-			// TODO(bradfitz): increment a varz here, once Transport
-			// takes an optional interface-typed field that expvar.Map.Add
-			// implements.
+			rl.closeWhenIdle = true
 		}
 		cs.resetErr = serr
 		close(cs.peerReset)

http2/transport_test.go

@@ -5296,78 +5296,3 @@ func (p *collectClientsConnPool) GetClientConn(req *http.Request, addr string) (
 func (p *collectClientsConnPool) MarkDead(cc *ClientConn) {
 	p.lower.MarkDead(cc)
 }
-
-func TestTransportRetriesOnStreamProtocolError(t *testing.T) {
-	ct := newClientTester(t)
-	pool := &collectClientsConnPool{
-		lower: &clientConnPool{t: ct.tr},
-	}
-	ct.tr.ConnPool = pool
-	done := make(chan struct{})
-	ct.client = func() error {
-		req, _ := http.NewRequest("GET", "https://dummy.tld/", nil)
-		res, err := ct.tr.RoundTrip(req)
-		const want = "only one dial allowed in test mode"
-		if got := fmt.Sprint(err); got != want {
-			t.Errorf("didn't dial again: got %#q; want %#q", got, want)
-		}
-		close(done)
-		ct.sc.Close()
-		if res != nil {
-			res.Body.Close()
-		}
-
-		pool.mu.Lock()
-		defer pool.mu.Unlock()
-		if pool.getErrs != 1 {
-			t.Errorf("pool get errors = %v; want 1", pool.getErrs)
-		}
-		if len(pool.got) == 1 {
-			cc := pool.got[0]
-			cc.mu.Lock()
-			if !cc.doNotReuse {
-				t.Error("ClientConn not marked doNotReuse")
-			}
-			cc.mu.Unlock()
-		} else {
-			t.Errorf("pool get success = %v; want 1", len(pool.got))
-		}
-		return nil
-	}
-	ct.server = func() error {
-		ct.greet()
-		var sentErr bool
-		for {
-			f, err := ct.fr.ReadFrame()
-			if err != nil {
-				select {
-				case <-done:
-					return nil
-				default:
-					return err
-				}
-			}
-			switch f := f.(type) {
-			case *WindowUpdateFrame, *SettingsFrame:
-			case *HeadersFrame:
-				if !sentErr {
-					sentErr = true
-					ct.fr.WriteRSTStream(f.StreamID, ErrCodeProtocol)
-					continue
-				}
-				var buf bytes.Buffer
-				enc := hpack.NewEncoder(&buf)
-				// send headers without Trailer header
-				enc.WriteField(hpack.HeaderField{Name: ":status", Value: "200"})
-				ct.fr.WriteHeaders(HeadersFrameParam{
-					StreamID:      f.StreamID,
-					EndHeaders:    true,
-					EndStream:     true,
-					BlockFragment: buf.Bytes(),
-				})
-			}
-		}
-		return nil
-	}
-	ct.run()
-}