init

go-gost/x/internal/net/udp/relay.go

@@ -0,0 +1,117 @@
+package udp
+
+import (
+	"context"
+	"math"
+	"net"
+
+	"github.com/go-gost/core/bypass"
+	"github.com/go-gost/core/logger"
+)
+
+const (
+	MaxMessageSize = math.MaxUint16
+)
+
+type Relay struct {
+	pc1 net.PacketConn
+	pc2 net.PacketConn
+
+	bypass bypass.Bypass
+	logger logger.Logger
+}
+
+func NewRelay(pc1, pc2 net.PacketConn) *Relay {
+	return &Relay{
+		pc1: pc1,
+		pc2: pc2,
+	}
+}
+
+func (r *Relay) WithBypass(bp bypass.Bypass) *Relay {
+	r.bypass = bp
+	return r
+}
+
+func (r *Relay) WithLogger(logger logger.Logger) *Relay {
+	r.logger = logger
+	return r
+}
+
+func (r *Relay) Run(ctx context.Context) (err error) {
+	errc := make(chan error, 2)
+
+	go func() {
+		var b [MaxMessageSize]byte
+		for {
+			err := func() error {
+				n, raddr, err := r.pc1.ReadFrom(b[:])
+				if err != nil {
+					return err
+				}
+
+				if r.bypass != nil && r.bypass.Contains(ctx, "udp", raddr.String()) {
+					if r.logger != nil {
+						r.logger.Warn("bypass: ", raddr)
+					}
+					return nil
+				}
+
+				if _, err := r.pc2.WriteTo(b[:n], raddr); err != nil {
+					return err
+				}
+
+				if r.logger != nil {
+					r.logger.Tracef("%s >>> %s data: %d",
+						r.pc2.LocalAddr(), raddr, n)
+
+				}
+
+				return nil
+			}()
+
+			if err != nil {
+				errc <- err
+				return
+			}
+		}
+	}()
+
+	go func() {
+		var b [MaxMessageSize]byte
+		for {
+			err := func() error {
+				n, raddr, err := r.pc2.ReadFrom(b[:])
+				if err != nil {
+					return err
+				}
+
+				if r.bypass != nil && r.bypass.Contains(ctx, "udp", raddr.String()) {
+					if r.logger != nil {
+						r.logger.Warn("bypass: ", raddr)
+					}
+					return nil
+				}
+
+				if _, err := r.pc1.WriteTo(b[:n], raddr); err != nil {
+					return err
+				}
+
+				if r.logger != nil {
+					r.logger.Tracef("%s <<< %s data: %d",
+						r.pc2.LocalAddr(), raddr, n)
+
+				}
+
+				return nil
+			}()
+
+			if err != nil {
+				errc <- err
+				return
+			}
+		}
+	}()
+
+	return <-errc
+}