347 lines
7.1 KiB
Go
347 lines
7.1 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/core/chain"
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"github.com/go-gost/core/common/bufpool"
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"github.com/go-gost/core/handler"
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"github.com/go-gost/core/hop"
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"github.com/go-gost/core/logger"
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md "github.com/go-gost/core/metadata"
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"github.com/go-gost/x/internal/util/ss"
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tap_util "github.com/go-gost/x/internal/util/tap"
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"github.com/go-gost/x/registry"
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"github.com/shadowsocks/go-shadowsocks2/core"
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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.HandlerRegistry().Register("tap", NewHandler)
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}
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type tapHandler struct {
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hop hop.Hop
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routes sync.Map
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exit chan struct{}
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cipher core.Cipher
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router *chain.Router
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md metadata
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options handler.Options
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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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exit: make(chan struct{}, 1),
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options: options,
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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
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}
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if h.options.Auth != nil {
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method := h.options.Auth.Username()
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password, _ := h.options.Auth.Password()
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h.cipher, err = ss.ShadowCipher(method, password, h.md.key)
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if err != nil {
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return
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}
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}
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h.router = h.options.Router
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if h.router == nil {
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h.router = chain.NewRouter(chain.LoggerRouterOption(h.options.Logger))
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}
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return
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}
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// Forward implements handler.Forwarder.
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func (h *tapHandler) Forward(hop hop.Hop) {
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h.hop = hop
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}
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func (h *tapHandler) Handle(ctx context.Context, conn net.Conn, opts ...handler.HandleOption) error {
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defer os.Exit(0)
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defer conn.Close()
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log := h.options.Logger
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v, _ := conn.(md.Metadatable)
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if v == nil {
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err := errors.New("tap: wrong connection type")
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log.Error(err)
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return err
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}
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start := time.Now()
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log = log.WithFields(map[string]any{
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"remote": conn.RemoteAddr().String(),
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"local": conn.LocalAddr().String(),
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})
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log.Infof("%s <> %s", conn.RemoteAddr(), conn.LocalAddr())
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defer func() {
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log.WithFields(map[string]any{
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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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var target *chain.Node
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if h.hop != nil {
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target = h.hop.Select(ctx)
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}
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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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log.Error(err)
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return err
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}
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log = log.WithFields(map[string]any{
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"dst": fmt.Sprintf("%s/%s", raddr.String(), raddr.Network()),
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})
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log.Debugf("%s >> %s", conn.RemoteAddr(), target.Addr)
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}
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config := v.Metadata().Get("config").(*tap_util.Config)
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h.handleLoop(ctx, conn, raddr, config, log)
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return nil
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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, log logger.Logger) {
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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(), "")
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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("wrong connection type")
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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.cipher != nil {
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pc = h.cipher.PacketConn(pc)
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}
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defer pc.Close()
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return h.transport(conn, pc, addr, config, log)
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}()
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if err != nil {
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log.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, config *tap_util.Config, log logger.Logger) 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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log.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 any) 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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log.Debugf("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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log.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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log.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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log.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 any) 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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log.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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