Adapt to current single connection per client

transport/internet/splithttp/dialer.go

@@ -270,7 +270,7 @@ func createHTTPClient(dest net.Destination, streamSettings *internet.MemoryStrea
 		raceTransport := &raceTransport{
 			h3:   makeH3Transport(),
 			h2:   makeH2Transport(),
-			dest: dest,
+			dest: dest.NetAddr(),
 		}
 		transport = raceTransport.setup()
 	default:

transport/internet/splithttp/race_dialer.go

@@ -4,28 +4,37 @@ import (
 	"context"
 	gotls "crypto/tls"
 	goerrors "errors"
-	gonet "net"
+	"fmt"
 	"net/http"
-	"strings"
 	"sync"
 	"sync/atomic"
 	"time"
-	"unsafe"
 
 	"github.com/xtls/quic-go"
 	"github.com/xtls/quic-go/http3"
 	"github.com/xtls/xray-core/common/errors"
 	"github.com/xtls/xray-core/common/net"
 	"golang.org/x/net/http2"
-	"golang.org/x/net/idna"
 )
 
 const (
+	// net/quic/quic_session_pool.cc
 	// QuicSessionPool::GetTimeDelayForWaitingJob > kDefaultRTT
-	chromeH2TryDelay = 300 * time.Millisecond
+	chromeH2DefaultTryDelay = 300 * time.Millisecond
+	// QuicSessionPool::GetTimeDelayForWaitingJob > srtt
+	chromeH2TryDelayScale = 1.5
 
+	// net/http/broken_alternative_services.cc
 	// kDefaultBrokenAlternativeProtocolDelay
-	chromeH3BrokenDelay = 5 * time.Minute
+	chromeH3BrokenInitialDelay = 5 * time.Minute
+	// kMaxBrokenAlternativeProtocolDelay
+	chromeH3BrokenMaxDelay = 48 * time.Hour
+	// kBrokenDelayMaxShift
+	chromeH3BrokenMaxShift = 18
+
+	// net/third_party/quiche/src/quiche/quic/core/congestion_control/rtt_stats.cc
+	// kAlpha
+	chromeH3SmoothRTTAlpha = 0.125
 )
 
 type raceKeyType struct{}
@@ -41,12 +50,14 @@ var (
 	brokenSpanError = goerrors.New("protocol temporarily broken")
 )
 
-type raceState int
+func isRaceInternalError(err error) bool {
+	return goerrors.Is(err, loseRaceError) || goerrors.Is(err, brokenSpanError)
+}
 
 const (
-	raceInitialized raceState = 0
-	raceEstablished raceState = 1
-	raceErrored     raceState = -1
+	raceInitialized = 0
+	raceEstablished = 1
+	raceErrored     = -1
 )
 
 type raceResult int
@@ -59,11 +70,118 @@ const (
 	raceInactive raceResult = -2
 )
 
+type endpointInfo struct {
+	lastFail  time.Time
+	failCount int
+	rtt       atomic.Int64
+}
+
+var h3EndpointCatalog map[string]*endpointInfo
+var h3EndpointCatalogLock sync.RWMutex
+
+func isH3Broken(endpoint string) bool {
+	h3EndpointCatalogLock.RLock()
+	defer h3EndpointCatalogLock.RUnlock()
+	info, ok := h3EndpointCatalog[endpoint]
+	if !ok {
+		return false
+	}
+
+	brokenDuration := min(chromeH3BrokenInitialDelay<<min(info.failCount, chromeH3BrokenMaxShift), chromeH3BrokenMaxDelay)
+	return time.Since(info.lastFail) < brokenDuration
+}
+
+func getH2Delay(endpoint string) time.Duration {
+	h3EndpointCatalogLock.RLock()
+	defer h3EndpointCatalogLock.RUnlock()
+	info, ok := h3EndpointCatalog[endpoint]
+	if !ok {
+		return chromeH2DefaultTryDelay
+	}
+	if info.failCount > 0 {
+		return 0
+	}
+	rtt := info.rtt.Load()
+	if rtt == 0 {
+		return chromeH2DefaultTryDelay
+	}
+	return time.Duration(chromeH2TryDelayScale * float64(rtt))
+}
+
+func updateH3Broken(endpoint string, brokenAt time.Time) int {
+	h3EndpointCatalogLock.Lock()
+	defer h3EndpointCatalogLock.Unlock()
+	if h3EndpointCatalog == nil {
+		h3EndpointCatalog = make(map[string]*endpointInfo)
+	}
+
+	info, ok := h3EndpointCatalog[endpoint]
+	if !ok {
+		h3EndpointCatalog[endpoint] = &endpointInfo{
+			lastFail:  brokenAt,
+			failCount: 1,
+		}
+		return 1
+	}
+
+	info.failCount++
+	if brokenAt.After(info.lastFail) {
+		info.lastFail = brokenAt
+	}
+
+	return info.failCount
+}
+
+func smoothedRtt(oldRtt, newRtt int64) int64 {
+	if oldRtt == 0 {
+		return newRtt
+	}
+
+	return int64((1-chromeH3SmoothRTTAlpha)*float64(oldRtt) + chromeH3SmoothRTTAlpha*float64(newRtt))
+}
+
+func updateH3RTT(endpoint string, rtt time.Duration) {
+	h3EndpointCatalogLock.RLock()
+	info, ok := h3EndpointCatalog[endpoint]
+	if !ok || info.failCount > 0 {
+		h3EndpointCatalogLock.RUnlock()
+		updateH3RTTSlow(endpoint, rtt)
+		return
+	}
+
+	defer h3EndpointCatalogLock.RUnlock()
+	for {
+		oldRtt := info.rtt.Load()
+		newRtt := smoothedRtt(oldRtt, int64(rtt))
+		if info.rtt.CompareAndSwap(oldRtt, newRtt) {
+			return
+		}
+	}
+}
+
+func updateH3RTTSlow(endpoint string, rtt time.Duration) {
+	h3EndpointCatalogLock.Lock()
+	defer h3EndpointCatalogLock.Unlock()
+
+	info, ok := h3EndpointCatalog[endpoint]
+	switch {
+	case !ok:
+		info = &endpointInfo{}
+		info.rtt.Store(int64(rtt))
+	case info.failCount > 0:
+		info.failCount = 0
+		info.lastFail = time.Time{}
+		info.rtt.Store(int64(rtt))
+	default:
+		info.rtt.Store(smoothedRtt(info.rtt.Load(), int64(rtt)))
+	}
+}
+
 type raceNotify struct {
 	c      chan struct{}
 	result raceResult
 
-	// left is the remove counter. This entry should be removed from race map when it reached 0
+	// left is the remove counter. It should be released when it reached 0
 	left atomic.Int32
 }
 
@@ -72,50 +190,16 @@ func (r *raceNotify) wait() raceResult {
 	return r.result
 }
 
-type raceInfo struct {
-	key    uintptr
-	host   string
-	notify *raceNotify
-}
-
 type raceTransport struct {
 	h3   *http3.Transport
 	h2   *http2.Transport
-	dest net.Destination
+	dest string
 
-	muFlag sync.Mutex
-	// flag must be read or write with muFlag holding.
-	flag map[uintptr]raceState
-
-	muRace sync.RWMutex
-	// race must be read or write with muRace holding.
-	// Entries are:
-	//  added by RoundTrip before racing start
-	//  removed by the last finished racer
-	race map[string]*raceNotify
-
-	h3broken atomic.Int64
-}
-
-func (t *raceTransport) isH3Broken() bool {
-	return time.Now().UnixNano()-t.h3broken.Load() < int64(chromeH3BrokenDelay)
-}
-
-func (t *raceTransport) updateH3Broken(broken time.Time) {
-	value := broken.UnixNano()
-	old := t.h3broken.Load()
-	for old < value {
-		if t.h3broken.CompareAndSwap(old, value) {
-			break
-		}
-		old = t.h3broken.Load()
-	}
+	flag   atomic.Int64
+	notify atomic.Pointer[raceNotify]
 }
 
 func (t *raceTransport) setup() *raceTransport {
-	t.flag = make(map[uintptr]raceState)
-	t.race = make(map[string]*raceNotify)
-
 	h3dial := t.h3.Dial
 	h2dial := t.h2.DialTLSContext
 
@@ -124,106 +208,108 @@ func (t *raceTransport) setup() *raceTransport {
 			return nil, http3.ErrNoCachedConn
 		}
 
-		info := ctx.Value(raceKey).(raceInfo)
-		key := info.key
+		var dialStart time.Time
+
 		defer func() {
+			notify := t.notify.Load()
+			if err == nil {
+				updateH3RTT(t.dest, time.Since(dialStart))
+				notify.result = raceH3
+				close(notify.c)
+			} else if !isRaceInternalError(err) {
+				failed := updateH3Broken(t.dest, time.Now())
+				errors.LogDebug(ctx, "Race Dialer: h3 connection to ", t.dest, " failed ", failed, "times")
+			}
+
 			// We can safely remove the raceNotify here, since both h2 and h3 Transport
 			// hold mutex while dialing.
 			// So another request can't slip in after we removed raceNotify but before
 			// Transport put the returned conn into pool - they will always reuse the conn we returned.
-			if err == nil {
-				info.notify.result = raceH3
-				close(info.notify.c)
-			}
-			if info.notify.left.Add(-1) == 0 {
+			if notify.left.Add(-1) == 0 {
 				errors.LogDebug(ctx, "Race Dialer: h3 cleaning race wait")
-				t.muRace.Lock()
-				if t.race[info.host] == info.notify {
-					delete(t.race, info.host)
-				}
-				t.muRace.Unlock()
+				t.notify.Store(nil)
 			}
 		}()
 
-		if t.isH3Broken() {
+		if isH3Broken(t.dest) {
 			return nil, brokenSpanError
 		}
 
-		t.muFlag.Lock()
-		established := t.flag[key]
-		t.muFlag.Unlock()
+		established := t.flag.Load()
 		if established == raceEstablished {
-			errors.LogDebug(ctx, "Race Dialer: h3 lose (h2 established)")
+			errors.LogDebug(ctx, "Race Dialer: h3 lose (h2 established before try)")
 			return nil, loseRaceError
 		}
 
+		dialStart = time.Now()
 		conn, err = h3dial(ctx, addr, tlsCfg, cfg)
 
-		t.muFlag.Lock()
-		established = t.flag[key]
 		if err != nil {
 			// We fail.
-			// Record if we are the first, cleanup if we are the last.
-			if established == raceInitialized {
-				t.flag[key] = raceErrored
+			// Record if we are the first.
+			if t.flag.CompareAndSwap(raceInitialized, raceErrored) {
 				errors.LogDebug(ctx, "Race Dialer: h3 lose (h3 error)")
 			} else {
-				delete(t.flag, key)
 				errors.LogDebug(ctx, "Race Dialer: h3 draw (both error)")
 			}
-			t.muFlag.Unlock()
 			return nil, err
 		}
 
-		switch established {
+		flag := t.flag.Load()
+		switch flag {
 		case raceEstablished:
 			// h2 wins.
-			delete(t.flag, key)
-			t.muFlag.Unlock()
 			_ = conn.CloseWithError(quic.ApplicationErrorCode(quic.NoError), "lose race")
-			errors.LogDebug(ctx, "Race Dialer: h3 lose (h2 established)")
+			errors.LogDebug(ctx, "Race Dialer: h3 lose (h2 established before handshake complete)")
 			return nil, loseRaceError
 		case raceErrored:
 			// h2 errored first. We will always be used.
-			delete(t.flag, key)
-			t.muFlag.Unlock()
 			errors.LogDebug(ctx, "Race Dialer: h3 win (h2 error)")
 			return conn, nil
+		case raceInitialized:
+			// continue
+		default:
+			panic(fmt.Sprintf("unreachable: unknown race flag: %d", flag))
 		}
 
 		// Don't consider we win until handshake completed.
-		t.muFlag.Unlock()
 		<-conn.HandshakeComplete()
 		errors.LogDebug(ctx, "Race Dialer: h3 handshake complete")
-		t.muFlag.Lock()
 
-		established = t.flag[key]
-		switch established {
+		if err = conn.Context().Err(); err != nil {
+			if t.flag.CompareAndSwap(raceInitialized, raceErrored) {
+				errors.LogDebug(ctx, "Race Dialer: h3 lose (h3 error first)")
+				return nil, err
+			}
+			_ = conn.CloseWithError(quic.ApplicationErrorCode(quic.NoError), "lose race")
+			conn = nil
+		} else {
+			if t.flag.CompareAndSwap(raceInitialized, raceEstablished) {
+				errors.LogDebug(ctx, "Race Dialer: h3 win (h3 first)")
+				return conn, nil
+			}
+		}
+
+		flag = t.flag.Load()
+		switch flag {
 		case raceEstablished:
 			// h2 wins.
-			delete(t.flag, key)
-			t.muFlag.Unlock()
 			_ = conn.CloseWithError(quic.ApplicationErrorCode(quic.NoError), "lose race")
 			errors.LogDebug(ctx, "Race Dialer: h3 lose (h2 established)")
 			return nil, loseRaceError
 		case raceErrored:
-			// h2 errored first. We clean up.
-			delete(t.flag, key)
-			errors.LogDebug(ctx, "Race Dialer: h3 win (h2 error)")
-		case raceInitialized:
-			// Check if handshake failed.
-			if err = conn.Context().Err(); err != nil {
-				conn = nil
-				t.flag[key] = raceErrored
-				errors.LogDebug(ctx, "Race Dialer: h3 lose (h3 error first)")
+			// h2 errored first.
+			if err == nil {
+				errors.LogDebug(ctx, "Race Dialer: h3 win (h2 error)")
 			} else {
-				t.flag[key] = raceEstablished
-				errors.LogDebug(ctx, "Race Dialer: h3 win (h3 first)")
+				errors.LogDebug(ctx, "Race Dialer: h3 draw (both error)")
 			}
+			return conn, err
+		case raceInitialized:
+			panic("unreachable: race flag should not revert to raceInitialized")
+		default:
+			panic(fmt.Sprintf("unreachable: unknown race flag: %d", flag))
 		}
-
-		t.muFlag.Unlock()
-		return conn, err
 	}
 
 	t.h2.DialTLSContext = func(ctx context.Context, network, addr string, cfg *gotls.Config) (conn net.Conn, err error) {
@@ -231,116 +317,84 @@ func (t *raceTransport) setup() *raceTransport {
 			return nil, http2.ErrNoCachedConn
 		}
 
-		info := ctx.Value(raceKey).(raceInfo)
-		key := info.key
 		defer func() {
+			notify := t.notify.Load()
 			if err == nil {
-				info.notify.result = raceH2
-				close(info.notify.c)
+				notify.result = raceH2
+				close(notify.c)
 			}
-			if info.notify.left.Add(-1) == 0 {
+			if notify.left.Add(-1) == 0 {
 				errors.LogDebug(ctx, "Race Dialer: h2 cleaning race wait")
-				t.muRace.Lock()
-				if t.race[info.host] == info.notify {
-					delete(t.race, info.host)
-				}
-				t.muRace.Unlock()
+				t.notify.Store(nil)
 			}
 		}()
 
-		if !t.isH3Broken() {
-			time.Sleep(chromeH2TryDelay)
-		}
+		delay := getH2Delay(t.dest)
+		errors.LogDebug(ctx, "Race Dialer: h2 dial delay: ", delay)
+		time.Sleep(delay)
 
-		t.muFlag.Lock()
-		established := t.flag[key]
-		t.muFlag.Unlock()
+		established := t.flag.Load()
 		if established == raceEstablished {
-			errors.LogDebug(ctx, "Race Dialer: h2 lose (h3 established)")
+			errors.LogDebug(ctx, "Race Dialer: h2 lose (h3 established before try)")
 			return nil, loseRaceError
 		}
 
 		conn, err = h2dial(ctx, network, addr, cfg)
 
-		t.muFlag.Lock()
-		established = t.flag[key]
 		if err != nil {
 			// We fail.
-			// Record if we are the first, cleanup if we are the last.
-			if established == raceInitialized {
-				t.flag[key] = raceErrored
+			// Record if we are the first.
+			if t.flag.CompareAndSwap(raceInitialized, raceErrored) {
 				errors.LogDebug(ctx, "Race Dialer: h2 lose (h2 error first)")
-			} else {
-				delete(t.flag, key)
-				errors.LogDebug(ctx, "Race Dialer: h2 draw (both error)")
+				return nil, err
+			}
+			_ = conn.Close()
+			conn = nil
+		} else {
+			if t.flag.CompareAndSwap(raceInitialized, raceEstablished) {
+				errors.LogDebug(ctx, "Race Dialer: h2 win (h2 first)")
+				return conn, nil
 			}
-			t.muFlag.Unlock()
-			return nil, err
 		}
 
-		switch established {
+		flag := t.flag.Load()
+		switch flag {
 		case raceEstablished:
 			// h3 wins.
-			delete(t.flag, key)
-			t.muFlag.Unlock()
 			_ = conn.Close()
 			errors.LogDebug(ctx, "Race Dialer: h2 lose (h3 established)")
 			return nil, loseRaceError
 		case raceErrored:
-			// h3 errored first. We clean up.
-			delete(t.flag, key)
-			errors.LogDebug(ctx, "Race Dialer: h2 win (h3 error)")
+			// h3 errored first.
+			if err == nil {
+				errors.LogDebug(ctx, "Race Dialer: h2 win (h3 error)")
+			} else {
+				errors.LogDebug(ctx, "Race Dialer: h2 draw (both error)")
+			}
+			return conn, err
 		case raceInitialized:
-			// We win, record.
-			t.flag[key] = raceEstablished
-			errors.LogDebug(ctx, "Race Dialer: h2 win (h2 first)")
+			panic("unreachable: race flag should not revert to raceInitialized")
+		default:
+			panic(fmt.Sprintf("unreachable: unknown race flag: %d", flag))
 		}
-
-		t.muFlag.Unlock()
-		return conn, nil
 	}
 
 	return t
 }
 
-func authorityAddr(scheme string, authority string) (addr string) {
-	host, port, err := net.SplitHostPort(authority)
-	if err != nil { // authority didn't have a port
-		host = authority
-		port = ""
-	}
-	if port == "" { // authority's port was empty
-		port = "443"
-		if scheme == "http" {
-			port = "80"
-		}
-	}
-	if a, err := idna.ToASCII(host); err == nil {
-		host = a
-	}
-	// IPv6 address literal, without a port:
-	if strings.HasPrefix(host, "[") && strings.HasSuffix(host, "]") {
-		return host + ":" + port
-	}
-	return gonet.JoinHostPort(host, port)
-}
-
 func (t *raceTransport) RoundTrip(req *http.Request) (*http.Response, error) {
 	ctx := req.Context()
 
-	// If there is inflight racing for current host, let it finish first,
+	// If there is inflight racing, let it finish first,
 	// so we can know and reuse winner's conn.
-	host := authorityAddr(req.URL.Scheme, req.URL.Host)
-	t.muRace.RLock()
-	notify, ok := t.race[host]
-	t.muRace.RUnlock()
+	notify := t.notify.Load()
+	raceResult := raceInactive
 
 WaitRace:
-	raceResult := raceInactive
-	if ok {
-		errors.LogDebug(ctx, "Race Dialer: found inflight race to ", t.dest.NetAddr(), ", waiting race winner")
+	if notify != nil {
+		errors.LogDebug(ctx, "Race Dialer: found inflight race to ", t.dest, ", waiting race winner")
 		raceResult = notify.wait()
-		errors.LogDebug(ctx, "Race Dialer: winner for ", t.dest.NetAddr(), " resolved, continue handling request")
+		errors.LogDebug(ctx, "Race Dialer: winner for ", t.dest, " resolved, continue handling request")
 	}
 
 	reqNoDial := req.WithContext(context.WithValue(ctx, noDialKey, struct{}{}))
@@ -353,7 +407,7 @@ WaitRace:
 	// - raceInflight: should not see this state.
 	if raceResult == raceH3 || raceResult == raceInactive {
 		if resp, err := t.h3.RoundTripOpt(reqNoDial, http3.RoundTripOpt{OnlyCachedConn: true}); err == nil {
-			errors.LogInfo(ctx, "Race Dialer: use h3 connection for ", t.dest.NetAddr(), " (reusing conn)")
+			errors.LogInfo(ctx, "Race Dialer: use h3 connection for ", t.dest, " (reusing conn)")
 			return resp, nil
 		} else if !goerrors.Is(err, http3.ErrNoCachedConn) {
 			return nil, err
@@ -365,7 +419,7 @@ WaitRace:
 	if raceResult == raceH2 || raceResult == raceInactive {
 		// http2.RoundTripOpt.OnlyCachedConn is not effective. However, our noDialKey will block dialing anyway.
 		if resp, err := t.h2.RoundTripOpt(reqNoDial, http2.RoundTripOpt{OnlyCachedConn: true}); err == nil {
-			errors.LogInfo(ctx, "Race Dialer: use h2 connection for ", t.dest.NetAddr(), " (reusing conn)")
+			errors.LogInfo(ctx, "Race Dialer: use h2 connection for ", t.dest, " (reusing conn)")
 			return resp, nil
 		} else if !goerrors.Is(err, http2.ErrNoCachedConn) {
 			return nil, err
@@ -375,35 +429,18 @@ WaitRace:
 	}
 
 	// Both don't have cached conn. Now race between h2 and h3.
-	t.muRace.Lock()
-	// Recheck
-	notify, ok = t.race[host]
-	if ok {
-		// Some other request started racing before us, we wait for them to finish.
-		t.muRace.Unlock()
-		goto WaitRace
-	}
-	// We are the goroutine to initialize racing.
+	// Recheck first.
 	notify = &raceNotify{c: make(chan struct{})}
 	notify.left.Store(2)
-	t.race[host] = notify
-	t.muRace.Unlock()
+	if !t.notify.CompareAndSwap(nil, notify) {
+		// Some other request started racing before us, we wait for them to finish.
+		goto WaitRace
+	}
 
-	errors.LogDebug(ctx, "Race Dialer: start race to ", t.dest.NetAddr())
+	// We are the goroutine to initialize racing.
+	errors.LogDebug(ctx, "Race Dialer: start race to ", t.dest)
 
-	// Both RoundTripper can share req.Body, because only one can dial successfully,
-	// and proceed to read request body.
-	key := uintptr(unsafe.Pointer(req))
-	raceCtx := context.WithValue(ctx, raceKey, raceInfo{
-		key:    key,
-		host:   host,
-		notify: notify,
-	})
-	req = req.WithContext(raceCtx)
-
-	t.muFlag.Lock()
-	t.flag[key] = raceInitialized
-	t.muFlag.Unlock()
+	t.flag.Store(raceInitialized)
 
 	h2resp := make(chan any)
 	h3resp := make(chan any)
@@ -417,36 +454,10 @@ WaitRace:
 		close(raceDone)
 	}()
 
-	go func() {
-		resp, err := t.h3.RoundTrip(req)
-
-		var result any
-		if err == nil {
-			result = resp
-			old := t.h3broken.Swap(0)
-			if old != 0 {
-				errors.LogDebug(ctx, "Race Dialer: h3 connection succeed, clear broken state")
-			}
-		} else {
-			result = err
-			t.updateH3Broken(time.Now())
-			errors.LogDebug(ctx, "Race Dialer: h3 connection failed, set broken state")
-		}
-
-		select {
-		case h3resp <- result:
-		case <-raceDone:
-		}
-	}()
-
-	go func() {
-		resp, err := t.h2.RoundTrip(req)
-		if notify.left.Add(-1) == 0 {
-			errors.LogDebug(ctx, "Race Dialer: h2 cleaning race wait")
-			t.muRace.Lock()
-			delete(t.race, host)
-			t.muRace.Unlock()
-		}
+	// Both RoundTripper can share req.Body, because only one can dial successfully,
+	// and proceed to read request body.
+	roundTrip := func(r http.RoundTripper, respChan chan any) {
+		resp, err := r.RoundTrip(req)
 
 		var result any
 		if err == nil {
@@ -456,17 +467,20 @@ WaitRace:
 		}
 
 		select {
-		case h2resp <- result:
+		case respChan <- result:
 		case <-raceDone:
 		}
-	}()
+	}
+
+	go roundTrip(t.h3, h3resp)
+	go roundTrip(t.h2, h2resp)
 
 	reportState := func(isH3 bool) {
 		winner := "h2"
 		if isH3 {
 			winner = "h3"
 		}
-		errors.LogInfo(ctx, "Race Dialer: use ", winner, " connection for ", t.dest.NetAddr(), " (race winner)")
+		errors.LogInfo(ctx, "Race Dialer: use ", winner, " connection for ", t.dest, " (race winner)")
 	}
 
 	handleResult := func(respErr any, other chan any, isH3 bool) (*http.Response, error) {
@@ -484,9 +498,9 @@ WaitRace:
 			case error:
 				switch {
 				// hide internal error
-				case goerrors.Is(value, loseRaceError) || goerrors.Is(value, brokenSpanError):
+				case isRaceInternalError(value):
 					return nil, otherValue
-				case goerrors.Is(otherValue, loseRaceError) || goerrors.Is(otherValue, brokenSpanError):
+				case isRaceInternalError(otherValue):
 					return nil, value
 				// prefer h3 error
 				case isH3:
@@ -495,10 +509,10 @@ WaitRace:
 					return nil, otherValue
 				}
 			default:
-				panic("unreachable: unexpected response type")
+				panic(fmt.Sprintf("unreachable: unexpected response type %T", otherValue))
 			}
 		default:
-			panic("unreachable: unexpected response type")
+			panic(fmt.Sprintf("unreachable: unexpected response type %T", value))
 		}
 	}