334 lines
6.9 KiB
Go
334 lines
6.9 KiB
Go
package tap
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import (
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"context"
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"errors"
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"fmt"
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"io"
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"net"
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"os"
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"sync"
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"time"
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"github.com/go-gost/gost/pkg/bypass"
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"github.com/go-gost/gost/pkg/chain"
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"github.com/go-gost/gost/pkg/common/bufpool"
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"github.com/go-gost/gost/pkg/handler"
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tap_util "github.com/go-gost/gost/pkg/internal/util/tap"
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"github.com/go-gost/gost/pkg/logger"
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md "github.com/go-gost/gost/pkg/metadata"
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"github.com/go-gost/gost/pkg/registry"
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"github.com/shadowsocks/go-shadowsocks2/shadowaead"
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"github.com/songgao/water/waterutil"
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)
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func init() {
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registry.RegisterHandler("tap", NewHandler)
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}
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type tapHandler struct {
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group *chain.NodeGroup
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bypass bypass.Bypass
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routes sync.Map
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exit chan struct{}
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router *chain.Router
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logger logger.Logger
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md metadata
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}
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func NewHandler(opts ...handler.Option) handler.Handler {
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options := &handler.Options{}
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for _, opt := range opts {
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opt(options)
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}
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return &tapHandler{
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bypass: options.Bypass,
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router: (&chain.Router{}).
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WithLogger(options.Logger).
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WithResolver(options.Resolver),
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logger: options.Logger,
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exit: make(chan struct{}, 1),
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}
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}
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func (h *tapHandler) Init(md md.Metadata) (err error) {
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if err := h.parseMetadata(md); err != nil {
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return err
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}
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h.router.WithRetry(h.md.retryCount)
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return nil
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}
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// implements chain.Chainable interface
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func (h *tapHandler) WithChain(chain *chain.Chain) {
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h.router.WithChain(chain)
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}
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// Forward implements handler.Forwarder.
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func (h *tapHandler) Forward(group *chain.NodeGroup) {
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h.group = group
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}
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func (h *tapHandler) Handle(ctx context.Context, conn net.Conn) {
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defer os.Exit(0)
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defer conn.Close()
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cc, ok := conn.(*tap_util.Conn)
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if !ok || cc.Config() == nil {
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h.logger.Error("invalid connection")
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return
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}
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start := time.Now()
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h.logger = h.logger.WithFields(map[string]interface{}{
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"remote": conn.RemoteAddr().String(),
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"local": conn.LocalAddr().String(),
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})
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h.logger.Infof("%s <> %s", conn.RemoteAddr(), conn.LocalAddr())
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defer func() {
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h.logger.WithFields(map[string]interface{}{
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"duration": time.Since(start),
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}).Infof("%s >< %s", conn.RemoteAddr(), conn.LocalAddr())
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}()
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network := "udp"
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var raddr net.Addr
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var err error
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target := h.group.Next()
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if target != nil {
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raddr, err = net.ResolveUDPAddr(network, target.Addr())
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if err != nil {
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h.logger.Error(err)
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return
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}
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h.logger = h.logger.WithFields(map[string]interface{}{
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"dst": fmt.Sprintf("%s/%s", raddr.String(), raddr.Network()),
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})
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h.logger.Infof("%s >> %s", conn.RemoteAddr(), target.Addr())
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}
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h.handleLoop(ctx, conn, raddr, cc.Config())
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}
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func (h *tapHandler) handleLoop(ctx context.Context, conn net.Conn, addr net.Addr, config *tap_util.Config) {
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var tempDelay time.Duration
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for {
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err := func() error {
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var err error
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var pc net.PacketConn
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if addr != nil {
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cc, err := h.router.Dial(ctx, addr.Network(), addr.String())
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if err != nil {
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return err
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}
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var ok bool
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pc, ok = cc.(net.PacketConn)
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if !ok {
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return errors.New("invalid connection")
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}
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} else {
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laddr, _ := net.ResolveUDPAddr("udp", conn.LocalAddr().String())
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pc, err = net.ListenUDP("udp", laddr)
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}
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if err != nil {
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return err
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}
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if h.md.cipher != nil {
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pc = h.md.cipher.PacketConn(pc)
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}
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return h.transport(conn, pc, addr)
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}()
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if err != nil {
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h.logger.Error(err)
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}
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select {
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case <-h.exit:
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return
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default:
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}
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if err != nil {
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if tempDelay == 0 {
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tempDelay = 1000 * time.Millisecond
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} else {
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tempDelay *= 2
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}
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if max := 6 * time.Second; tempDelay > max {
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tempDelay = max
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}
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time.Sleep(tempDelay)
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continue
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}
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tempDelay = 0
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}
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}
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func (h *tapHandler) transport(tap net.Conn, conn net.PacketConn, raddr net.Addr) error {
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errc := make(chan error, 1)
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go func() {
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for {
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err := func() error {
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b := bufpool.Get(h.md.bufferSize)
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defer bufpool.Put(b)
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n, err := tap.Read(b)
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if err != nil {
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select {
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case h.exit <- struct{}{}:
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default:
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}
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return err
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}
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src := waterutil.MACSource(b[:n])
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dst := waterutil.MACDestination(b[:n])
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eType := etherType(waterutil.MACEthertype(b[:n]))
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h.logger.Debugf("%s >> %s %s %d", src, dst, eType, n)
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// client side, deliver frame directly.
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if raddr != nil {
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_, err := conn.WriteTo(b[:n], raddr)
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return err
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}
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// server side, broadcast.
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if waterutil.IsBroadcast(dst) {
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go h.routes.Range(func(k, v interface{}) bool {
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conn.WriteTo(b[:n], v.(net.Addr))
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return true
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})
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return nil
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}
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var addr net.Addr
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if v, ok := h.routes.Load(hwAddrToTapRouteKey(dst)); ok {
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addr = v.(net.Addr)
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}
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if addr == nil {
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h.logger.Warnf("no route for %s -> %s %s %d", src, dst, eType, n)
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return nil
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}
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if _, err := conn.WriteTo(b[:n], addr); err != nil {
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return err
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}
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return nil
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}()
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if err != nil {
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errc <- err
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return
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}
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}
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}()
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go func() {
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for {
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err := func() error {
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b := bufpool.Get(h.md.bufferSize)
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defer bufpool.Put(b)
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n, addr, err := conn.ReadFrom(b)
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if err != nil &&
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err != shadowaead.ErrShortPacket {
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return err
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}
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src := waterutil.MACSource(b[:n])
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dst := waterutil.MACDestination(b[:n])
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eType := etherType(waterutil.MACEthertype(b[:n]))
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h.logger.Debugf("%s >> %s %s %d", src, dst, eType, n)
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// client side, deliver frame to tap device.
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if raddr != nil {
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_, err := tap.Write(b[:n])
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return err
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}
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// server side, record route.
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rkey := hwAddrToTapRouteKey(src)
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if actual, loaded := h.routes.LoadOrStore(rkey, addr); loaded {
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if actual.(net.Addr).String() != addr.String() {
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h.logger.Debugf("update route: %s -> %s (old %s)",
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src, addr, actual.(net.Addr))
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h.routes.Store(rkey, addr)
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}
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} else {
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h.logger.Debugf("new route: %s -> %s", src, addr)
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}
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if waterutil.IsBroadcast(dst) {
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go h.routes.Range(func(k, v interface{}) bool {
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if k.(tapRouteKey) != rkey {
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conn.WriteTo(b[:n], v.(net.Addr))
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}
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return true
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})
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}
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if v, ok := h.routes.Load(hwAddrToTapRouteKey(dst)); ok {
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h.logger.Debugf("find route: %s -> %s", dst, v)
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_, err := conn.WriteTo(b[:n], v.(net.Addr))
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return err
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}
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if _, err := tap.Write(b[:n]); err != nil {
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select {
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case h.exit <- struct{}{}:
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default:
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}
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return err
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}
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return nil
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}()
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if err != nil {
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errc <- err
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return
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}
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}
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}()
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err := <-errc
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if err != nil && err == io.EOF {
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err = nil
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}
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return err
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}
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var mEtherTypes = map[waterutil.Ethertype]string{
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waterutil.IPv4: "ip",
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waterutil.ARP: "arp",
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waterutil.RARP: "rarp",
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waterutil.IPv6: "ip6",
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}
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func etherType(et waterutil.Ethertype) string {
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if s, ok := mEtherTypes[et]; ok {
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return s
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}
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return fmt.Sprintf("unknown(%v)", et)
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}
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type tapRouteKey [6]byte
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func hwAddrToTapRouteKey(addr net.HardwareAddr) (key tapRouteKey) {
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copy(key[:], addr)
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return
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}
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