Fix concurrency vmess udp write

adapter/outbound/vmess.go

@@ -9,6 +9,7 @@ import (
 	"net/http"
 	"strconv"
 	"strings"
+	"sync"
 
 	"github.com/Dreamacro/clash/common/convert"
 	"github.com/Dreamacro/clash/component/dialer"
@@ -267,19 +268,19 @@ func (v *Vmess) ListenPacketContext(ctx context.Context, metadata *C.Metadata, o
 	}
 
 	if v.option.PacketAddr {
-		return newPacketConn(packetaddr.NewBindClient(c), v), nil
+		return newPacketConn(&threadSafePacketConn{PacketConn: packetaddr.NewBindClient(c)}, v), nil
 	} else if pc, ok := c.(net.PacketConn); ok {
-		return newPacketConn(pc, v), nil
+		return newPacketConn(&threadSafePacketConn{PacketConn: pc}, v), nil
 	}
 	return newPacketConn(&vmessPacketConn{Conn: c, rAddr: metadata.UDPAddr()}, v), nil
 }
 
 // ListenPacketOnStreamConn implements C.ProxyAdapter
 func (v *Vmess) ListenPacketOnStreamConn(c net.Conn, metadata *C.Metadata) (_ C.PacketConn, err error) {
 	if v.option.PacketAddr {
-		return newPacketConn(packetaddr.NewBindClient(c), v), nil
+		return newPacketConn(&threadSafePacketConn{PacketConn: packetaddr.NewBindClient(c)}, v), nil
 	} else if pc, ok := c.(net.PacketConn); ok {
-		return newPacketConn(pc, v), nil
+		return newPacketConn(&threadSafePacketConn{PacketConn: pc}, v), nil
 	}
 	return newPacketConn(&vmessPacketConn{Conn: c, rAddr: metadata.UDPAddr()}, v), nil
 }
@@ -357,12 +358,26 @@ func NewVmess(option VmessOption) (*Vmess, error) {
 	return v, nil
 }
 
+type threadSafePacketConn struct {
+	net.PacketConn
+	access sync.Mutex
+}
+
+func (c *threadSafePacketConn) WriteTo(b []byte, addr net.Addr) (int, error) {
+	c.access.Lock()
+	defer c.access.Unlock()
+	return c.PacketConn.WriteTo(b, addr)
+}
+
 type vmessPacketConn struct {
 	net.Conn
-	rAddr net.Addr
+	rAddr  net.Addr
+	access sync.Mutex
 }
 
 func (uc *vmessPacketConn) WriteTo(b []byte, addr net.Addr) (int, error) {
+	uc.access.Lock()
+	defer uc.access.Unlock()
 	return uc.Conn.Write(b)
 }