fix: incorrectly throw error when 5.2<=kernel<5.5

common/consts/ebpf.go

@@ -5,6 +5,8 @@
 
 package consts
 
+import internal "github.com/v2rayA/dae/pkg/ebpf_internal"
+
 const (
 	AppName    = "dae"
 	BpfPinRoot = "/sys/fs/bpf"
@@ -93,3 +95,5 @@ const (
 	IpVersion_6 IpVersion = 2
 	IpVersion_X IpVersion = 3
 )
+
+var FtraceFeatureVersion = internal.Version{5, 5, 0}

component/control/bpf_utils.go

@@ -95,3 +95,37 @@ func BatchUpdate(m *ebpf.Map, keys interface{}, values interface{}, opts *ebpf.B
 		return vKeys.Len(), nil
 	}
 }
+
+type bpfObjectsLan struct {
+	// NOTICE: Consider to update me if any program added.
+	TproxyEgress  *ebpf.Program `ebpf:"tproxy_egress"`
+	TproxyIngress *ebpf.Program `ebpf:"tproxy_ingress"`
+
+	bpfMaps
+}
+
+func AssignBpfPrograms(to *bpfObjects, from interface{}) {
+	vTo := reflect.Indirect(reflect.ValueOf(to))
+	vFrom := reflect.Indirect(reflect.ValueOf(from))
+	tFrom := vFrom.Type()
+	// programs
+	for i := 0; i < vFrom.NumField(); i++ {
+		fieldFrom := vFrom.Field(i)
+		structFieldFrom := tFrom.Field(i)
+		if structFieldFrom.Type != reflect.TypeOf(&ebpf.Program{}) {
+			continue
+		}
+		fieldTo := vTo.FieldByName(structFieldFrom.Name)
+		fieldTo.Set(fieldFrom)
+	}
+
+	// bpfMaps
+	vFrom = vFrom.FieldByName("bpfMaps")
+	tFrom = vFrom.Type()
+	for i := 0; i < vFrom.NumField(); i++ {
+		fieldFrom := vFrom.Field(i)
+		structFieldFrom := tFrom.Field(i)
+		fieldTo := vTo.FieldByName(structFieldFrom.Name)
+		fieldTo.Set(fieldFrom)
+	}
+}

component/control/control_plane.go

@@ -38,6 +38,8 @@ import (
 type ControlPlane struct {
 	log *logrus.Logger
 
+	kernelVersion *internal.Version
+
 	// TODO: add mutex?
 	outbounds       []*outbound.DialerGroup
 	outboundName2Id map[string]uint8
@@ -64,6 +66,11 @@ func NewControlPlane(
 	checkUrl string,
 	checkInterval time.Duration,
 ) (c *ControlPlane, err error) {
+	kernelVersion, e := internal.KernelVersion()
+	if e != nil {
+		return nil, fmt.Errorf("failed to get kernel version: %w", e)
+	}
+
 	// Allow the current process to lock memory for eBPF resources.
 	if err = rlimit.RemoveMemlock(); err != nil {
 		return nil, fmt.Errorf("rlimit.RemoveMemlock:%v", err)
@@ -73,14 +80,20 @@ func NewControlPlane(
 
 	// Load pre-compiled programs and maps into the kernel.
 	var bpf bpfObjects
+	var bpfLan bpfObjectsLan
 	var ProgramOptions ebpf.ProgramOptions
 	if log.IsLevelEnabled(logrus.TraceLevel) {
 		ProgramOptions = ebpf.ProgramOptions{
 			LogLevel: ebpf.LogLevelStats,
 		}
 	}
+	var obj interface{} = &bpf
+	if kernelVersion.Less(consts.FtraceFeatureVersion) {
+		// Trick. Replace the beams with rotten timbers.
+		obj = &bpfLan
+	}
 retryLoadBpf:
-	if err = loadBpfObjects(&bpf, &ebpf.CollectionOptions{
+	if err = loadBpfObjects(obj, &ebpf.CollectionOptions{
 		Maps: ebpf.MapOptions{
 			PinPath: pinPath,
 		},
@@ -110,6 +123,11 @@ retryLoadBpf:
 		}
 		return nil, fmt.Errorf("loading objects: %v", err)
 	}
+	if kernelVersion.Less(consts.FtraceFeatureVersion) {
+		// Reverse takeover.
+		AssignBpfPrograms(&bpf, &bpfLan)
+	}
+
 	// Write params.
 	if err = bpf.ParamMap.Update(consts.DisableL4TxChecksumKey, consts.DisableL4ChecksumPolicy_SetZero, ebpf.UpdateAny); err != nil {
 		return nil, err
@@ -235,6 +253,7 @@ retryLoadBpf:
 
 	return &ControlPlane{
 		log:                log,
+		kernelVersion:      &kernelVersion,
 		outbounds:          outbounds,
 		outboundName2Id:    outboundName2Id,
 		bpf:                &bpf,
@@ -369,22 +388,17 @@ func (c *ControlPlane) BindLan(ifname string) error {
 }
 
 func (c *ControlPlane) BindWan(ifname string) error {
+	if c.kernelVersion.Less(consts.FtraceFeatureVersion) {
+		// Not support ftrace (fentry/fexit).
+		// PID bypass needs it.
+		return fmt.Errorf("your kernel version %v does not support bind to WAN; expect >=%v; remove wan_interface in config file and try again", c.kernelVersion.String(), consts.FtraceFeatureVersion.String())
+	}
+
 	link, err := netlink.LinkByName(ifname)
 	if err != nil {
 		return err
 	}
 
-	version, e := internal.KernelVersion()
-	if e != nil {
-		return fmt.Errorf("BindWan: failed to get kernel version: %w", e)
-	}
-	ftraceFeatureVersion := internal.Version{5, 5, 0}
-	if version.Less(ftraceFeatureVersion) {
-		// Not support ftrace (fentry/fexit).
-		// PID bypass needs it.
-		return fmt.Errorf("your kernel version %v does not support bind to WAN; expect >=%v", version.String(), ftraceFeatureVersion.String())
-	}
-
 	// Set-up SrcPidMapper.
 	// Attach programs to support pname routing.
 

component/control/routing_matcher_builder.go

@@ -50,7 +50,7 @@ func (b *RoutingMatcherBuilder) OutboundToId(outbound string) uint8 {
 		var ok bool
 		outboundId, ok = b.outboundName2Id[outbound]
 		if !ok {
-			b.err = fmt.Errorf("%v not in outboundName2Id", strconv.Quote(outbound))
+			b.err = fmt.Errorf("%v not defined in group", strconv.Quote(outbound))
 		}
 	}
 	return outboundId