package udp
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import (
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"context"
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"io"
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"sync"
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"time"
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"github.com/v2fly/v2ray-core/v5/common"
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"github.com/v2fly/v2ray-core/v5/common/buf"
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"github.com/v2fly/v2ray-core/v5/common/net"
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"github.com/v2fly/v2ray-core/v5/common/protocol/udp"
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"github.com/v2fly/v2ray-core/v5/common/session"
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"github.com/v2fly/v2ray-core/v5/common/signal"
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"github.com/v2fly/v2ray-core/v5/common/signal/done"
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"github.com/v2fly/v2ray-core/v5/features/routing"
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"github.com/v2fly/v2ray-core/v5/transport"
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)
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type ResponseCallback func(ctx context.Context, packet *udp.Packet)
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type connEntry struct {
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link *transport.Link
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timer signal.ActivityUpdater
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cancel context.CancelFunc
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}
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type Dispatcher struct {
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sync.RWMutex
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conns map[net.Destination]*connEntry
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dispatcher routing.Dispatcher
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callback ResponseCallback
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}
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func (v *Dispatcher) Close() error {
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return nil
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}
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func NewSplitDispatcher(dispatcher routing.Dispatcher, callback ResponseCallback) DispatcherI {
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return &Dispatcher{
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conns: make(map[net.Destination]*connEntry),
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dispatcher: dispatcher,
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callback: callback,
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}
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}
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func (v *Dispatcher) RemoveRay(dest net.Destination) {
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v.Lock()
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defer v.Unlock()
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if conn, found := v.conns[dest]; found {
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common.Close(conn.link.Reader)
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common.Close(conn.link.Writer)
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delete(v.conns, dest)
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}
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}
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func (v *Dispatcher) getInboundRay(ctx context.Context, dest net.Destination) *connEntry {
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v.Lock()
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defer v.Unlock()
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if entry, found := v.conns[dest]; found {
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return entry
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}
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newError("establishing new connection for ", dest).WriteToLog()
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ctx, cancel := context.WithCancel(ctx)
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removeRay := func() {
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cancel()
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v.RemoveRay(dest)
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}
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timer := signal.CancelAfterInactivity(ctx, removeRay, time.Second*4)
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link, _ := v.dispatcher.Dispatch(ctx, dest)
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entry := &connEntry{
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link: link,
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timer: timer,
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cancel: removeRay,
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}
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v.conns[dest] = entry
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go handleInput(ctx, entry, dest, v.callback)
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return entry
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}
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func (v *Dispatcher) Dispatch(ctx context.Context, destination net.Destination, payload *buf.Buffer) {
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// TODO: Add user to destString
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newError("dispatch request to: ", destination).AtDebug().WriteToLog(session.ExportIDToError(ctx))
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conn := v.getInboundRay(ctx, destination)
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outputStream := conn.link.Writer
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if outputStream != nil {
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if err := outputStream.WriteMultiBuffer(buf.MultiBuffer{payload}); err != nil {
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newError("failed to write first UDP payload").Base(err).WriteToLog(session.ExportIDToError(ctx))
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conn.cancel()
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return
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}
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}
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}
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func handleInput(ctx context.Context, conn *connEntry, dest net.Destination, callback ResponseCallback) {
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defer conn.cancel()
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input := conn.link.Reader
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timer := conn.timer
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for {
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select {
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case <-ctx.Done():
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return
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default:
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}
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mb, err := input.ReadMultiBuffer()
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if err != nil {
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newError("failed to handle UDP input").Base(err).WriteToLog(session.ExportIDToError(ctx))
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return
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}
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timer.Update()
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for _, b := range mb {
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callback(ctx, &udp.Packet{
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Payload: b,
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Source: dest,
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})
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}
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}
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}
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type dispatcherConn struct {
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dispatcher *Dispatcher
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cache chan *udp.Packet
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done *done.Instance
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}
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func DialDispatcher(ctx context.Context, dispatcher routing.Dispatcher) (net.PacketConn, error) {
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c := &dispatcherConn{
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cache: make(chan *udp.Packet, 16),
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done: done.New(),
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}
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d := NewSplitDispatcher(dispatcher, c.callback)
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c.dispatcher = d.(*Dispatcher)
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return c, nil
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}
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func (c *dispatcherConn) callback(ctx context.Context, packet *udp.Packet) {
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select {
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case <-c.done.Wait():
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packet.Payload.Release()
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return
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case c.cache <- packet:
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default:
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packet.Payload.Release()
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return
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}
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}
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func (c *dispatcherConn) ReadFrom(p []byte) (int, net.Addr, error) {
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select {
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case <-c.done.Wait():
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return 0, nil, io.EOF
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case packet := <-c.cache:
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n := copy(p, packet.Payload.Bytes())
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return n, &net.UDPAddr{
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IP: packet.Source.Address.IP(),
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Port: int(packet.Source.Port),
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}, nil
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}
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}
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func (c *dispatcherConn) WriteTo(p []byte, addr net.Addr) (int, error) {
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buffer := buf.New()
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raw := buffer.Extend(buf.Size)
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n := copy(raw, p)
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buffer.Resize(0, int32(n))
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ctx := context.Background()
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c.dispatcher.Dispatch(ctx, net.DestinationFromAddr(addr), buffer)
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return n, nil
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}
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func (c *dispatcherConn) Close() error {
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return c.done.Close()
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}
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func (c *dispatcherConn) LocalAddr() net.Addr {
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return &net.UDPAddr{
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IP: []byte{0, 0, 0, 0},
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Port: 0,
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}
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}
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func (c *dispatcherConn) SetDeadline(t time.Time) error {
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return nil
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}
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func (c *dispatcherConn) SetReadDeadline(t time.Time) error {
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return nil
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}
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func (c *dispatcherConn) SetWriteDeadline(t time.Time) error {
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return nil
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}
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