From ec9b64e5ec2ab5b5b22e8f0a31a0b17f12b1aac1 Mon Sep 17 00:00:00 2001
From: Shelikhoo <xiaokangwang@outlook.com>
Date: Mon, 13 Dec 2021 21:52:57 +0000
Subject: [PATCH] Add packet addr dispatcher

---
 .../internet/udp/dispatcher_packetaddr.go     | 57 +++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 transport/internet/udp/dispatcher_packetaddr.go

diff --git a/transport/internet/udp/dispatcher_packetaddr.go b/transport/internet/udp/dispatcher_packetaddr.go
new file mode 100644
index 000000000..35f3e2e60
--- /dev/null
+++ b/transport/internet/udp/dispatcher_packetaddr.go
@@ -0,0 +1,57 @@
+package udp
+
+import (
+	"context"
+	"github.com/v2fly/v2ray-core/v4/common/buf"
+	"github.com/v2fly/v2ray-core/v4/common/net"
+	"github.com/v2fly/v2ray-core/v4/common/net/packetaddr"
+	"github.com/v2fly/v2ray-core/v4/common/protocol/udp"
+	"github.com/v2fly/v2ray-core/v4/features/routing"
+)
+
+type PacketAddrDispatcher struct {
+	conn     net.PacketConn
+	callback ResponseCallback
+	ctx      context.Context
+}
+
+func (p PacketAddrDispatcher) Close() error {
+	return p.conn.Close()
+}
+
+func (p PacketAddrDispatcher) Dispatch(ctx context.Context, destination net.Destination, payload *buf.Buffer) {
+	if destination.Network != net.Network_UDP {
+		return
+	}
+	p.conn.WriteTo(payload.Bytes(), &net.UDPAddr{IP: destination.Address.IP(), Port: int(destination.Port.Value())})
+}
+func (p PacketAddrDispatcher) readWorker() {
+	for {
+		readBuf := buf.New()
+		n, addr, err := p.conn.ReadFrom(readBuf.Extend(2048))
+		if err != nil {
+			return
+		}
+		readBuf.Resize(0, int32(n))
+		p.callback(p.ctx, &udp.Packet{Payload: readBuf, Source: net.DestinationFromAddr(addr)})
+	}
+}
+
+type PacketAddrDispatcherCreator struct {
+	ctx context.Context
+}
+
+func NewPacketAddrDispatcherCreator(ctx context.Context) PacketAddrDispatcherCreator {
+	return PacketAddrDispatcherCreator{ctx: ctx}
+}
+
+func (pdc *PacketAddrDispatcherCreator) NewPacketAddrDispatcher(
+	dispatcher routing.Dispatcher, callback ResponseCallback) (DispatcherI, error) {
+	packetConn, err := packetaddr.CreatePacketAddrConn(pdc.ctx, dispatcher, false)
+	if err != nil {
+		return nil, err
+	}
+	pd := &PacketAddrDispatcher{conn: packetConn, callback: callback, ctx: pdc.ctx}
+	go pd.readWorker()
+	return pd, nil
+}