164 lines
3.5 KiB
Go
164 lines
3.5 KiB
Go
package relay
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import (
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"context"
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"errors"
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"net"
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"strconv"
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"time"
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"github.com/go-gost/core/chain"
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"github.com/go-gost/core/handler"
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md "github.com/go-gost/core/metadata"
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"github.com/go-gost/relay"
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"github.com/go-gost/x/registry"
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)
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var (
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ErrBadVersion = errors.New("relay: bad version")
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ErrUnknownCmd = errors.New("relay: unknown command")
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)
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func init() {
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registry.HandlerRegistry().Register("relay", NewHandler)
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}
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type relayHandler struct {
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group *chain.NodeGroup
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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 &relayHandler{
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options: options,
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}
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}
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func (h *relayHandler) 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 = h.options.Router
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if h.router == nil {
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h.router = (&chain.Router{}).WithLogger(h.options.Logger)
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}
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return nil
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}
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// Forward implements handler.Forwarder.
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func (h *relayHandler) Forward(group *chain.NodeGroup) {
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h.group = group
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}
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func (h *relayHandler) Handle(ctx context.Context, conn net.Conn, opts ...handler.HandleOption) error {
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defer conn.Close()
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start := time.Now()
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log := h.options.Logger.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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if !h.checkRateLimit(conn.RemoteAddr()) {
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return nil
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}
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if h.md.readTimeout > 0 {
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conn.SetReadDeadline(time.Now().Add(h.md.readTimeout))
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}
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req := relay.Request{}
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if _, err := req.ReadFrom(conn); err != nil {
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log.Error(err)
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return err
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}
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conn.SetReadDeadline(time.Time{})
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if req.Version != relay.Version1 {
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err := ErrBadVersion
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log.Error(err)
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return err
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}
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var user, pass string
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var address string
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for _, f := range req.Features {
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if f.Type() == relay.FeatureUserAuth {
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feature := f.(*relay.UserAuthFeature)
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user, pass = feature.Username, feature.Password
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}
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if f.Type() == relay.FeatureAddr {
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feature := f.(*relay.AddrFeature)
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address = net.JoinHostPort(feature.Host, strconv.Itoa(int(feature.Port)))
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}
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}
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if user != "" {
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log = log.WithFields(map[string]any{"user": user})
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}
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resp := relay.Response{
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Version: relay.Version1,
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Status: relay.StatusOK,
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}
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if h.options.Auther != nil && !h.options.Auther.Authenticate(user, pass) {
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resp.Status = relay.StatusUnauthorized
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log.Error("unauthorized")
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_, err := resp.WriteTo(conn)
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return err
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}
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network := "tcp"
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if (req.Flags & relay.FUDP) == relay.FUDP {
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network = "udp"
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}
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if h.group != nil {
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if address != "" {
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resp.Status = relay.StatusForbidden
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log.Error("forward mode, connect is forbidden")
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_, err := resp.WriteTo(conn)
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return err
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}
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// forward mode
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return h.handleForward(ctx, conn, network, log)
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}
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switch req.Flags & relay.CmdMask {
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case 0, relay.CONNECT:
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return h.handleConnect(ctx, conn, network, address, log)
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case relay.BIND:
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return h.handleBind(ctx, conn, network, address, log)
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}
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return ErrUnknownCmd
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}
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func (h *relayHandler) checkRateLimit(addr net.Addr) bool {
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if h.options.RateLimiter == nil {
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return true
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}
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host, _, _ := net.SplitHostPort(addr.String())
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if limiter := h.options.RateLimiter.Limiter(host); limiter != nil {
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return limiter.Allow(1)
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}
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return true
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}
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