init

go-gost/x/handler/ss/udp/handler.go

@@ -0,0 +1,228 @@
+package ss
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"net"
+	"time"
+
+	"github.com/go-gost/core/handler"
+	"github.com/go-gost/core/logger"
+	md "github.com/go-gost/core/metadata"
+	"github.com/go-gost/core/recorder"
+	ctxvalue "github.com/go-gost/x/ctx"
+	"github.com/go-gost/x/internal/util/relay"
+	"github.com/go-gost/x/internal/util/ss"
+	rate_limiter "github.com/go-gost/x/limiter/rate"
+	xrecorder "github.com/go-gost/x/recorder"
+	"github.com/go-gost/x/registry"
+	"github.com/shadowsocks/go-shadowsocks2/core"
+)
+
+func init() {
+	registry.HandlerRegistry().Register("ssu", NewHandler)
+}
+
+type ssuHandler struct {
+	cipher   core.Cipher
+	md       metadata
+	options  handler.Options
+	recorder recorder.RecorderObject
+}
+
+func NewHandler(opts ...handler.Option) handler.Handler {
+	options := handler.Options{}
+	for _, opt := range opts {
+		opt(&options)
+	}
+
+	return &ssuHandler{
+		options: options,
+	}
+}
+
+func (h *ssuHandler) Init(md md.Metadata) (err error) {
+	if err = h.parseMetadata(md); err != nil {
+		return
+	}
+
+	if h.options.Auth != nil {
+		method := h.options.Auth.Username()
+		password, _ := h.options.Auth.Password()
+		h.cipher, err = ss.ShadowCipher(method, password, h.md.key)
+		if err != nil {
+			return
+		}
+	}
+
+	for _, ro := range h.options.Recorders {
+		if ro.Record == xrecorder.RecorderServiceHandler {
+			h.recorder = ro
+			break
+		}
+	}
+
+	return
+}
+
+func (h *ssuHandler) Handle(ctx context.Context, conn net.Conn, opts ...handler.HandleOption) (err error) {
+	defer conn.Close()
+
+	start := time.Now()
+
+	ro := &xrecorder.HandlerRecorderObject{
+		Service:    h.options.Service,
+		Network:    "udp",
+		RemoteAddr: conn.RemoteAddr().String(),
+		LocalAddr:  conn.LocalAddr().String(),
+		Time:       start,
+		SID:        string(ctxvalue.SidFromContext(ctx)),
+	}
+	ro.ClientIP, _, _ = net.SplitHostPort(conn.RemoteAddr().String())
+
+	log := h.options.Logger.WithFields(map[string]any{
+		"remote": conn.RemoteAddr().String(),
+		"local":  conn.LocalAddr().String(),
+		"sid":    ctxvalue.SidFromContext(ctx),
+	})
+
+	log.Infof("%s <> %s", conn.RemoteAddr(), conn.LocalAddr())
+	defer func() {
+		if err != nil {
+			ro.Err = err.Error()
+		}
+		ro.Duration = time.Since(start)
+		ro.Record(ctx, h.recorder.Recorder)
+
+		log.WithFields(map[string]any{
+			"duration": time.Since(start),
+		}).Infof("%s >< %s", conn.RemoteAddr(), conn.LocalAddr())
+	}()
+
+	if !h.checkRateLimit(conn.RemoteAddr()) {
+		return rate_limiter.ErrRateLimit
+	}
+
+	pc, ok := conn.(net.PacketConn)
+	if ok {
+		if h.cipher != nil {
+			pc = h.cipher.PacketConn(pc)
+		}
+		// standard UDP relay.
+		pc = ss.UDPServerConn(pc, conn.RemoteAddr())
+	} else {
+		if h.cipher != nil {
+			conn = ss.ShadowConn(h.cipher.StreamConn(conn), nil)
+		}
+		// UDP over TCP
+		pc = relay.UDPTunServerConn(conn)
+	}
+
+	// obtain a udp connection
+	var buf bytes.Buffer
+	c, err := h.options.Router.Dial(ctxvalue.ContextWithBuffer(ctx, &buf), "udp", "") // UDP association
+	ro.Route = buf.String()
+	if err != nil {
+		log.Error(err)
+		return err
+	}
+	defer c.Close()
+
+	cc, ok := c.(net.PacketConn)
+	if !ok {
+		err := errors.New("ss: wrong connection type")
+		log.Error(err)
+		return err
+	}
+
+	t := time.Now()
+	log.Infof("%s <-> %s", conn.LocalAddr(), cc.LocalAddr())
+	h.relayPacket(ctx, pc, cc, ro, log)
+	log.WithFields(map[string]any{"duration": time.Since(t)}).
+		Infof("%s >-< %s", conn.LocalAddr(), cc.LocalAddr())
+
+	return nil
+}
+
+func (h *ssuHandler) relayPacket(ctx context.Context, pc1, pc2 net.PacketConn, ro *xrecorder.HandlerRecorderObject, log logger.Logger) (err error) {
+	errc := make(chan error, 2)
+
+	go func() {
+		var b [MaxMessageSize]byte
+		for {
+			err := func() error {
+				n, addr, err := pc1.ReadFrom(b[:])
+				if err != nil {
+					return err
+				}
+
+				if ro.Host == "" {
+					ro.Host = addr.String()
+				}
+
+				if h.options.Bypass != nil && h.options.Bypass.Contains(ctx, addr.Network(), addr.String()) {
+					log.Warn("bypass: ", addr)
+					return nil
+				}
+
+				if _, err = pc2.WriteTo(b[:n], addr); err != nil {
+					return err
+				}
+
+				log.Tracef("%s >>> %s data: %d",
+					pc2.LocalAddr(), addr, n)
+				return nil
+			}()
+
+			if err != nil {
+				errc <- err
+				return
+			}
+		}
+	}()
+
+	go func() {
+		var b [MaxMessageSize]byte
+		for {
+			err := func() error {
+				n, raddr, err := pc2.ReadFrom(b[:])
+				if err != nil {
+					return err
+				}
+
+				if h.options.Bypass != nil && h.options.Bypass.Contains(ctx, raddr.Network(), raddr.String()) {
+					log.Warn("bypass: ", raddr)
+					return nil
+				}
+
+				if _, err = pc1.WriteTo(b[:n], raddr); err != nil {
+					return err
+				}
+
+				log.Tracef("%s <<< %s data: %d",
+					pc2.LocalAddr(), raddr, n)
+				return nil
+			}()
+
+			if err != nil {
+				errc <- err
+				return
+			}
+		}
+	}()
+
+	return <-errc
+}
+
+func (h *ssuHandler) checkRateLimit(addr net.Addr) bool {
+	if h.options.RateLimiter == nil {
+		return true
+	}
+	host, _, _ := net.SplitHostPort(addr.String())
+	if limiter := h.options.RateLimiter.Limiter(host); limiter != nil {
+		return limiter.Allow(1)
+	}
+
+	return true
+}