update tun handler

2022-08-21 13:54:52 +08:00
parent d61b1ba1b3
commit ca414f655d
6 changed files with 366 additions and 285 deletions
--- a/handler/tun/server.go
+++ b/handler/tun/server.go
@ -0,0 +1,166 @@
+package tun
+
+import (
+	"context"
+	"io"
+	"net"
+
+	"github.com/go-gost/core/common/bufpool"
+	"github.com/go-gost/core/logger"
+	tun_util "github.com/go-gost/x/internal/util/tun"
+	"github.com/songgao/water/waterutil"
+	"golang.org/x/net/ipv4"
+	"golang.org/x/net/ipv6"
+)
+
+func (h *tunHandler) handleServer(ctx context.Context, conn net.Conn, config *tun_util.Config, log logger.Logger) error {
+	pc, err := net.ListenPacket(conn.LocalAddr().Network(), conn.LocalAddr().String())
+	if err != nil {
+		return err
+	}
+	defer pc.Close()
+
+	return h.transportServer(conn, pc, config, log)
+}
+
+func (h *tunHandler) transportServer(tun net.Conn, conn net.PacketConn, config *tun_util.Config, log logger.Logger) error {
+	errc := make(chan error, 1)
+
+	go func() {
+		for {
+			err := func() error {
+				b := bufpool.Get(h.md.bufferSize)
+				defer bufpool.Put(b)
+
+				n, err := tun.Read(*b)
+				if err != nil {
+					return err
+				}
+
+				var src, dst net.IP
+				if waterutil.IsIPv4((*b)[:n]) {
+					header, err := ipv4.ParseHeader((*b)[:n])
+					if err != nil {
+						log.Warn(err)
+						return nil
+					}
+					src, dst = header.Src, header.Dst
+
+					log.Tracef("%s >> %s %-4s %d/%-4d %-4x %d",
+						header.Src, header.Dst, ipProtocol(waterutil.IPv4Protocol((*b)[:n])),
+						header.Len, header.TotalLen, header.ID, header.Flags)
+				} else if waterutil.IsIPv6((*b)[:n]) {
+					header, err := ipv6.ParseHeader((*b)[:n])
+					if err != nil {
+						log.Warn(err)
+						return nil
+					}
+					src, dst = header.Src, header.Dst
+
+					log.Tracef("%s >> %s %s %d %d",
+						header.Src, header.Dst,
+						ipProtocol(waterutil.IPProtocol(header.NextHeader)),
+						header.PayloadLen, header.TrafficClass)
+				} else {
+					log.Warn("unknown packet, discarded")
+					return nil
+				}
+
+				addr := h.findRouteFor(dst, config.Routes...)
+				if addr == nil {
+					log.Debugf("no route for %s -> %s, packet discarded", src, dst)
+					return nil
+				}
+
+				log.Debugf("find route: %s -> %s", dst, addr)
+
+				if _, err := conn.WriteTo((*b)[:n], addr); err != nil {
+					return err
+				}
+				return nil
+			}()
+
+			if err != nil {
+				errc <- err
+				return
+			}
+		}
+	}()
+
+	go func() {
+		for {
+			err := func() error {
+				b := bufpool.Get(h.md.bufferSize)
+				defer bufpool.Put(b)
+
+				n, addr, err := conn.ReadFrom(*b)
+				if err != nil {
+					return err
+				}
+
+				var src, dst net.IP
+				if waterutil.IsIPv4((*b)[:n]) {
+					header, err := ipv4.ParseHeader((*b)[:n])
+					if err != nil {
+						log.Warn(err)
+						return nil
+					}
+					src, dst = header.Src, header.Dst
+
+					log.Tracef("%s >> %s %-4s %d/%-4d %-4x %d",
+						header.Src, header.Dst, ipProtocol(waterutil.IPv4Protocol((*b)[:n])),
+						header.Len, header.TotalLen, header.ID, header.Flags)
+				} else if waterutil.IsIPv6((*b)[:n]) {
+					header, err := ipv6.ParseHeader((*b)[:n])
+					if err != nil {
+						log.Warn(err)
+						return nil
+					}
+					src, dst = header.Src, header.Dst
+
+					log.Tracef("%s > %s %s %d %d",
+						header.Src, header.Dst,
+						ipProtocol(waterutil.IPProtocol(header.NextHeader)),
+						header.PayloadLen, header.TrafficClass)
+				} else {
+					log.Warn("unknown packet, discarded")
+					return nil
+				}
+
+				rkey := ipToTunRouteKey(src)
+				if actual, loaded := h.routes.LoadOrStore(rkey, addr); loaded {
+					if actual.(net.Addr).String() != addr.String() {
+						h.routes.Store(rkey, addr)
+						log.Debugf("update route: %s -> %s (old %s)",
+							src, addr, actual.(net.Addr))
+					}
+				} else {
+					log.Debugf("new route: %s -> %s", src, addr)
+				}
+
+				if addr := h.findRouteFor(dst, config.Routes...); addr != nil {
+					log.Debugf("find route: %s -> %s", dst, addr)
+
+					_, err := conn.WriteTo((*b)[:n], addr)
+					return err
+				}
+
+				if _, err := tun.Write((*b)[:n]); err != nil {
+					return err
+				}
+				return nil
+			}()
+
+			if err != nil {
+				errc <- err
+				return
+			}
+		}
+	}()
+
+	err := <-errc
+	if err != nil && err == io.EOF {
+		err = nil
+	}
+	return err
+}