add socks

pkg/handler/socks/v4/handler.go

@@ -0,0 +1,165 @@
+package v4
+
+import (
+	"context"
+	"net"
+	"time"
+
+	"github.com/go-gost/gosocks4"
+	"github.com/go-gost/gost/pkg/auth"
+	"github.com/go-gost/gost/pkg/bypass"
+	"github.com/go-gost/gost/pkg/chain"
+	"github.com/go-gost/gost/pkg/handler"
+	"github.com/go-gost/gost/pkg/logger"
+	md "github.com/go-gost/gost/pkg/metadata"
+	"github.com/go-gost/gost/pkg/registry"
+)
+
+func init() {
+	registry.RegisterHandler("socks4", NewHandler)
+	registry.RegisterHandler("socks4a", NewHandler)
+}
+
+type socks4Handler struct {
+	chain  *chain.Chain
+	bypass bypass.Bypass
+	logger logger.Logger
+	md     metadata
+}
+
+func NewHandler(opts ...handler.Option) handler.Handler {
+	options := &handler.Options{}
+	for _, opt := range opts {
+		opt(options)
+	}
+
+	return &socks4Handler{
+		chain:  options.Chain,
+		bypass: options.Bypass,
+		logger: options.Logger,
+	}
+}
+
+func (h *socks4Handler) Init(md md.Metadata) (err error) {
+	return h.parseMetadata(md)
+}
+
+func (h *socks4Handler) Handle(ctx context.Context, conn net.Conn) {
+	defer conn.Close()
+
+	start := time.Now()
+
+	h.logger = h.logger.WithFields(map[string]interface{}{
+		"remote": conn.RemoteAddr().String(),
+		"local":  conn.LocalAddr().String(),
+	})
+
+	h.logger.Infof("%s <> %s", conn.RemoteAddr(), conn.LocalAddr())
+	defer func() {
+		h.logger.WithFields(map[string]interface{}{
+			"duration": time.Since(start),
+		}).Infof("%s >< %s", conn.RemoteAddr(), conn.LocalAddr())
+	}()
+
+	if h.md.readTimeout > 0 {
+		conn.SetReadDeadline(time.Now().Add(h.md.readTimeout))
+	}
+
+	req, err := gosocks4.ReadRequest(conn)
+	if err != nil {
+		h.logger.Error(err)
+		return
+	}
+	conn.SetReadDeadline(time.Time{})
+
+	if h.logger.IsLevelEnabled(logger.DebugLevel) {
+		h.logger.Debug(req)
+	}
+
+	if h.md.authenticator != nil &&
+		!h.md.authenticator.Authenticate(string(req.Userid), "") {
+		resp := gosocks4.NewReply(gosocks4.RejectedUserid, nil)
+		resp.Write(conn)
+		if h.logger.IsLevelEnabled(logger.DebugLevel) {
+			h.logger.Debug(resp)
+		}
+		return
+	}
+
+	switch req.Cmd {
+	case gosocks4.CmdConnect:
+		h.handleConnect(ctx, conn, req)
+	case gosocks4.CmdBind:
+		h.handleBind(ctx, conn, req)
+	default:
+		h.logger.Errorf("unknown cmd: %d", req.Cmd)
+	}
+}
+
+func (h *socks4Handler) handleConnect(ctx context.Context, conn net.Conn, req *gosocks4.Request) {
+	addr := req.Addr.String()
+
+	h.logger = h.logger.WithFields(map[string]interface{}{
+		"dst": addr,
+	})
+	h.logger.Infof("%s >> %s", conn.RemoteAddr(), addr)
+
+	if h.bypass != nil && h.bypass.Contains(addr) {
+		resp := gosocks4.NewReply(gosocks4.Rejected, nil)
+		resp.Write(conn)
+		if h.logger.IsLevelEnabled(logger.DebugLevel) {
+			h.logger.Debug(resp)
+		}
+		h.logger.Info("bypass: ", addr)
+		return
+	}
+
+	r := (&handler.Router{}).
+		WithChain(h.chain).
+		WithRetry(h.md.retryCount).
+		WithLogger(h.logger)
+	cc, err := r.Dial(ctx, "tcp", addr)
+	if err != nil {
+		resp := gosocks4.NewReply(gosocks4.Failed, nil)
+		resp.Write(conn)
+		if h.logger.IsLevelEnabled(logger.DebugLevel) {
+			h.logger.Debug(resp)
+		}
+		return
+	}
+
+	defer cc.Close()
+
+	resp := gosocks4.NewReply(gosocks4.Granted, nil)
+	if err := resp.Write(conn); err != nil {
+		h.logger.Error(err)
+		return
+	}
+	if h.logger.IsLevelEnabled(logger.DebugLevel) {
+		h.logger.Debug(resp)
+	}
+
+	h.logger.Infof("%s <-> %s", conn.RemoteAddr(), addr)
+	handler.Transport(conn, cc)
+	h.logger.Infof("%s >-< %s", conn.RemoteAddr(), addr)
+}
+
+func (h *socks4Handler) handleBind(ctx context.Context, conn net.Conn, req *gosocks4.Request) {
+	// TODO: bind
+}
+
+func (h *socks4Handler) parseMetadata(md md.Metadata) (err error) {
+	if v, _ := md.Get(authsKey).([]interface{}); len(v) > 0 {
+		authenticator := auth.NewLocalAuthenticator(nil)
+		for _, auth := range v {
+			if v, _ := auth.(string); v != "" {
+				authenticator.Add(v, "")
+			}
+		}
+		h.md.authenticator = authenticator
+	}
+
+	h.md.readTimeout = md.GetDuration(readTimeout)
+	h.md.retryCount = md.GetInt(retryCount)
+	return
+}