From 820da78f92c53758b4b4c6f0c145cdc9fc6789b8 Mon Sep 17 00:00:00 2001
From: V2Ray <admin@v2ray.com>
Date: Fri, 2 Oct 2015 16:08:01 +0200
Subject: [PATCH] UDP handler in VMess in.

---
 proxy/vmess/protocol/udp.go |  5 ++++
 proxy/vmess/vmessin_udp.go  | 57 +++++++++++++++++++++++++++++++++++++
 2 files changed, 62 insertions(+)
 create mode 100644 proxy/vmess/vmessin_udp.go

diff --git a/proxy/vmess/protocol/udp.go b/proxy/vmess/protocol/udp.go
index 00d4669ec..e4e5d6787 100644
--- a/proxy/vmess/protocol/udp.go
+++ b/proxy/vmess/protocol/udp.go
@@ -20,6 +20,11 @@ type VMessUDP struct {
 	data    []byte
 }
 
+func (message *VMessUDP) ToPacket() v2net.Packet {
+	dest := v2net.NewUDPDestination(message.address)
+	return v2net.NewPacket(dest, message.data, false)
+}
+
 func ReadVMessUDP(buffer []byte, userset user.UserSet) (*VMessUDP, error) {
 	userHash := buffer[:user.IDBytesLen]
 	userId, timeSec, valid := userset.GetUser(userHash)
diff --git a/proxy/vmess/vmessin_udp.go b/proxy/vmess/vmessin_udp.go
new file mode 100644
index 000000000..48061931c
--- /dev/null
+++ b/proxy/vmess/vmessin_udp.go
@@ -0,0 +1,57 @@
+package vmess
+
+import (
+	"net"
+
+	"github.com/v2ray/v2ray-core/common/log"
+	v2net "github.com/v2ray/v2ray-core/common/net"
+	"github.com/v2ray/v2ray-core/proxy/vmess/protocol"
+)
+
+const (
+	bufferSize = 2 * 1024
+)
+
+func (handler *VMessInboundHandler) ListenUDP(port uint16) error {
+	addr := &net.UDPAddr{
+		IP:   net.IP{0, 0, 0, 0},
+		Port: int(port),
+		Zone: "",
+	}
+	conn, err := net.ListenUDP("udp", addr)
+	if err != nil {
+		log.Error("VMessIn failed to listen UDP on port %d: %v", port, err)
+		return err
+	}
+
+	go handler.AcceptPackets(conn)
+	return nil
+}
+
+func (handler *VMessInboundHandler) AcceptPackets(conn *net.UDPConn) error {
+	for {
+		buffer := make([]byte, 0, bufferSize)
+		nBytes, addr, err := conn.ReadFromUDP(buffer)
+		if err != nil {
+			log.Error("VMessIn failed to read UDP packets: %v", err)
+			return err
+		}
+		request, err := protocol.ReadVMessUDP(buffer[:nBytes], handler.clients)
+		if err != nil {
+			log.Error("VMessIn failed to parse UDP request: %v", err)
+			return err
+		}
+
+		udpPacket := request.ToPacket()
+		go handler.handlePacket(conn, udpPacket, addr)
+	}
+}
+
+func (handler *VMessInboundHandler) handlePacket(conn *net.UDPConn, packet v2net.Packet, clientAddr *net.UDPAddr) {
+	ray := handler.vPoint.DispatchToOutbound(packet)
+	close(ray.InboundInput())
+
+	if data, ok := <-ray.InboundOutput(); ok {
+		conn.WriteToUDP(data, clientAddr)
+	}
+}