prevent close of closed

Bumps google.golang.org/protobuf from 1.36.7 to 1.36.8.

---
updated-dependencies:
- dependency-name: google.golang.org/protobuf
  dependency-version: 1.36.8
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

go.mod

@@ -27,7 +27,7 @@ require (
 	golang.org/x/sys v0.35.0
 	golang.zx2c4.com/wireguard v0.0.0-20231211153847-12269c276173
 	google.golang.org/grpc v1.75.0
-	google.golang.org/protobuf v1.36.7
+	google.golang.org/protobuf v1.36.8
 	gvisor.dev/gvisor v0.0.0-20250428193742-2d800c3129d5
 	h12.io/socks v1.0.3
 	lukechampine.com/blake3 v1.4.1

go.sum

@@ -145,8 +145,8 @@ google.golang.org/genproto/googleapis/rpc v0.0.0-20250707201910-8d1bb00bc6a7 h1:
 google.golang.org/genproto/googleapis/rpc v0.0.0-20250707201910-8d1bb00bc6a7/go.mod h1:qQ0YXyHHx3XkvlzUtpXDkS29lDSafHMZBAZDc03LQ3A=
 google.golang.org/grpc v1.75.0 h1:+TW+dqTd2Biwe6KKfhE5JpiYIBWq865PhKGSXiivqt4=
 google.golang.org/grpc v1.75.0/go.mod h1:JtPAzKiq4v1xcAB2hydNlWI2RnF85XXcV0mhKXr2ecQ=
-google.golang.org/protobuf v1.36.7 h1:IgrO7UwFQGJdRNXH/sQux4R1Dj1WAKcLElzeeRaXV2A=
-google.golang.org/protobuf v1.36.7/go.mod h1:jduwjTPXsFjZGTmRluh+L6NjiWu7pchiJ2/5YcXBHnY=
+google.golang.org/protobuf v1.36.8 h1:xHScyCOEuuwZEc6UtSOvPbAT4zRh0xcNRYekJwfqyMc=
+google.golang.org/protobuf v1.36.8/go.mod h1:fuxRtAxBytpl4zzqUh6/eyUujkJdNiuEkXntxiD/uRU=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=

proxy/dns/dns.go

@@ -5,6 +5,7 @@ import (
 	go_errors "errors"
 	"io"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/xtls/xray-core/common"
@@ -369,6 +370,10 @@ type outboundConn struct {
 	access sync.Mutex
 	dialer func() (stat.Connection, error)
 
+	closeOnce sync.Once
+	dialOnce  sync.Once
+	closed    atomic.Bool
+
 	conn      net.Conn
 	connReady chan struct{}
 }
@@ -378,24 +383,28 @@ func (c *outboundConn) dial() error {
 	if err != nil {
 		return err
 	}
+	if c.closed.Load() {
+		return errors.New("connection closed during dial")
+	}
 	c.conn = conn
 	c.connReady <- struct{}{}
 	return nil
 }
 
 func (c *outboundConn) Write(b []byte) (int, error) {
+	c.dialOnce.Do(func() {
+		c.dial()
+	})
 	c.access.Lock()
-
-	if c.conn == nil {
-		if err := c.dial(); err != nil {
-			c.access.Unlock()
-			errors.LogWarningInner(context.Background(), err, "failed to dial outbound connection")
-			return len(b), nil
-		}
-	}
-
+	conn := c.conn
 	c.access.Unlock()
-
+	if conn == nil {
+		_, open := <-c.connReady
+		if !open {
+			return 0, io.EOF
+		}
+		conn = c.conn
+	}
 	return c.conn.Write(b)
 }
 
@@ -417,11 +426,14 @@ func (c *outboundConn) Read(b []byte) (int, error) {
 }
 
 func (c *outboundConn) Close() error {
-	c.access.Lock()
-	close(c.connReady)
-	if c.conn != nil {
-		c.conn.Close()
-	}
-	c.access.Unlock()
+	c.closeOnce.Do(func() {
+		c.access.Lock()
+		c.closed.Store(true)
+		close(c.connReady)
+		if c.conn != nil {
+			c.conn.Close()
+		}
+		c.access.Unlock()
+	})
 	return nil
 }