Mux server: Clone the session.Content attached on ctx as well

https://github.com/XTLS/Xray-core/pull/3908#issuecomment-2696911994

Fixes https://github.com/XTLS/Xray-core/pull/3904 for good

common/session/session.go

@@ -4,7 +4,6 @@ package session // import "github.com/xtls/xray-core/common/session"
 import (
 	"context"
 	"math/rand"
-	"sync"
 
 	c "github.com/xtls/xray-core/common/ctx"
 	"github.com/xtls/xray-core/common/errors"
@@ -75,8 +74,8 @@ type Outbound struct {
 
 // SniffingRequest controls the behavior of content sniffing.
 type SniffingRequest struct {
-	ExcludeForDomain               []string
-	OverrideDestinationForProtocol []string
+	ExcludeForDomain               []string // read-only once set
+	OverrideDestinationForProtocol []string // read-only once set
 	Enabled                        bool
 	MetadataOnly                   bool
 	RouteOnly                      bool
@@ -92,10 +91,6 @@ type Content struct {
 	Attributes map[string]string
 
 	SkipDNSResolve bool
-
-	mu sync.Mutex
-
-	isLocked bool
 }
 
 // Sockopt is the settings for socket connection.
@@ -104,22 +99,8 @@ type Sockopt struct {
 	Mark int32
 }
 
-// Some how when using mux, there will be a same ctx between different requests
-// This will cause problem as it's designed for single request, like concurrent map writes
-// Add a Mutex as a temp solution
-
 // SetAttribute attaches additional string attributes to content.
 func (c *Content) SetAttribute(name string, value string) {
-	if c.isLocked {
-		errors.LogError(context.Background(), "Multiple goroutines are tring to access one routing content, tring to write ", name, ":", value)
-	}
-	c.mu.Lock()
-	c.isLocked = true
-	defer func() {
-		c.isLocked = false
-		c.mu.Unlock()
-	}()
-
 	if c.Attributes == nil {
 		c.Attributes = make(map[string]string)
 	}
@@ -128,24 +109,8 @@ func (c *Content) SetAttribute(name string, value string) {
 
 // Attribute retrieves additional string attributes from content.
 func (c *Content) Attribute(name string) string {
-	c.mu.Lock()
-	c.isLocked = true
-	defer func() {
-		c.isLocked = false
-		c.mu.Unlock()
-	}()
 	if c.Attributes == nil {
 		return ""
 	}
 	return c.Attributes[name]
 }
-
-func (c *Content) AttributeLen() int {
-	c.mu.Lock()
-	c.isLocked = true
-	defer func() {
-		c.isLocked = false
-		c.mu.Unlock()
-	}()
-	return len(c.Attributes)
-}