feat: introduce a new robust approach to handle tproxy udp. (#389)

constant/adapters.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"net"
 	"net/netip"
+	"sync"
 	"time"
 
 	"github.com/Dreamacro/clash/component/dialer"
@@ -216,6 +217,10 @@ type UDPPacket interface {
 
 	// LocalAddr returns the source IP/Port of packet
 	LocalAddr() net.Addr
+
+	SetNatTable(natTable NatTable)
+
+	SetUdpInChan(in chan<- PacketAdapter)
 }
 
 type UDPPacketInAddr interface {
@@ -227,3 +232,23 @@ type PacketAdapter interface {
 	UDPPacket
 	Metadata() *Metadata
 }
+
+type NatTable interface {
+	Set(key string, e PacketConn)
+
+	Get(key string) PacketConn
+
+	GetOrCreateLock(key string) (*sync.Cond, bool)
+
+	Delete(key string)
+
+	GetLocalConn(lAddr, rAddr string) *net.UDPConn
+
+	AddLocalConn(lAddr, rAddr string, conn *net.UDPConn) bool
+
+	RangeLocalConn(lAddr string, f func(key, value any) bool)
+
+	GetOrCreateLockForLocalConn(lAddr, key string) (*sync.Cond, bool)
+
+	DeleteLocalConnMap(lAddr, key string)
+}