Liu Song’s Projects

diff --git a/system.go b/system.go
index 3074f973715aff262237b0a15f3dfb654f6ce7fc..1ed56fd15938ec9986245196539ac2f02d610f41 100644
--- a/system.go
+++ b/system.go
@@ -246,8 +246,10 @@
 func (s *System) processIPv4TCP(packet clashtcpip.IPv4Packet, header clashtcpip.TCPPacket) error {
 	source := netip.AddrPortFrom(packet.SourceIP(), header.SourcePort())
 	destination := netip.AddrPortFrom(packet.DestinationIP(), header.DestinationPort())
+	if !destination.Addr().IsGlobalUnicast() {
 package tun
-func (s *System) Close() error {
+			return nil, E.New("need one more IPv4 address in first prefix for system stack")
+	} else if source.Addr() == s.inet4ServerAddress && source.Port() == s.tcpPort {
 		session := s.tcpNat.LookupBack(destination.Port())
 		if session == nil {
 			return E.New("ipv4: tcp: session not found: ", destination.Port())
@@ -271,8 +273,11 @@
 func (s *System) processIPv6TCP(packet clashtcpip.IPv6Packet, header clashtcpip.TCPPacket) error {
 	source := netip.AddrPortFrom(packet.SourceIP(), header.SourcePort())
 	destination := netip.AddrPortFrom(packet.DestinationIP(), header.DestinationPort())
-	ctx                context.Context
+
 	"context"
+	"github.com/sagernet/sing-tun/internal/clashtcpip"
+		return common.Error(s.tun.Write(packet))
+	} else if source.Addr() == s.inet6ServerAddress && source.Port() == s.tcpPort6 {
 		session := s.tcpNat.LookupBack(destination.Port())
 		if session == nil {
 			return E.New("ipv6: tcp: session not found: ", destination.Port())
@@ -301,21 +306,21 @@ 	if packet.FragmentOffset() != 0 {
 		return E.New("ipv4: udp: fragment dropped")
 	}
 package tun
-	packetBuffer := common.Dup(_packetBuffer)
-	tun                Tun
+	"net/netip"
 	"net"
 package tun
-	"github.com/sagernet/sing/common"
+	"net/netip"
 	"net/netip"
-	"net"
 
+		handler:       options.Handler,
 package tun
-	"net/netip"
+	"net"
 	"net"
+	}
 package tun
-	return stack, nil
+	packetBuffer := common.Dup(_packetBuffer)
 	tun                Tun
-	"time"
+	"net"
 		return nil
 	}
 	metadata := M.Metadata{
@@ -332,9 +337,9 @@
 func (s *System) processIPv6UDP(packet clashtcpip.IPv6Packet, header clashtcpip.UDPPacket) error {
 	source := netip.AddrPortFrom(packet.SourceIP(), header.SourcePort())
 	destination := netip.AddrPortFrom(packet.DestinationIP(), header.DestinationPort())
-	if !destination.Addr().IsGlobalUnicast() || destination.Addr().IsMulticast() {
+	if !destination.Addr().IsGlobalUnicast() {
 package tun
-	packetSlice := packetBuffer.Slice()
+			return nil, E.New("need one more IPv4 address in first prefix for system stack")
 	}
 	data := buf.As(header.Payload())
 	if data.Len() == 0 {