feat(internal/wireguard): opportunistic kernelspace

- Auto detect if kernelspace implementation is available
- Fallback to Go userspace implementation if kernel is not available

internal/netlink/family.go

@@ -1,6 +1,10 @@
 package netlink
 
-import "github.com/vishvananda/netlink"
+import (
+	"fmt"
+
+	"github.com/vishvananda/netlink"
+)
 
 //nolint:revive
 const (
@@ -8,3 +12,20 @@ const (
 	FAMILY_V4  = netlink.FAMILY_V4
 	FAMILY_V6  = netlink.FAMILY_V6
 )
+
+type WireguardChecker interface {
+	IsWireguardSupported() (ok bool, err error)
+}
+
+func (n *NetLink) IsWireguardSupported() (ok bool, err error) {
+	families, err := netlink.GenlFamilyList()
+	if err != nil {
+		return false, fmt.Errorf("cannot list gen 1 families: %w", err)
+	}
+	for _, family := range families {
+		if family.Name == "wireguard" {
+			return true, nil
+		}
+	}
+	return false, nil
+}

internal/netlink/family_test.go

@@ -0,0 +1,21 @@
+package netlink
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func Test_NetLink_IsWireguardSupported(t *testing.T) {
+	t.Skip() // TODO unskip once the data race problem with netlink.GenlFamilyList() is fixed
+
+	t.Parallel()
+	netLink := &NetLink{}
+	ok, err := netLink.IsWireguardSupported()
+	require.NoError(t, err)
+	if ok { // cannot assert since this depends on kernel
+		t.Log("wireguard is supported")
+	} else {
+		t.Log("wireguard is not supported")
+	}
+}

internal/netlink/interface.go

@@ -9,4 +9,5 @@ type NetLinker interface {
 	Linker
 	Router
 	Ruler
+	WireguardChecker
 }

internal/netlink/link.go

@@ -3,8 +3,9 @@ package netlink
 import "github.com/vishvananda/netlink"
 
 type (
-	Link   = netlink.Link
-	Bridge = netlink.Bridge
+	Link      = netlink.Link
+	Bridge    = netlink.Bridge
+	Wireguard = netlink.Wireguard
 )
 
 var _ Linker = (*NetLink)(nil)

internal/netlink/mock_netlink/interface.go

@@ -63,6 +63,21 @@ func (mr *MockNetLinkerMockRecorder) AddrList(arg0, arg1 interface{}) *gomock.Ca
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "AddrList", reflect.TypeOf((*MockNetLinker)(nil).AddrList), arg0, arg1)
 }
 
+// IsWireguardSupported mocks base method.
+func (m *MockNetLinker) IsWireguardSupported() (bool, error) {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "IsWireguardSupported")
+	ret0, _ := ret[0].(bool)
+	ret1, _ := ret[1].(error)
+	return ret0, ret1
+}
+
+// IsWireguardSupported indicates an expected call of IsWireguardSupported.
+func (mr *MockNetLinkerMockRecorder) IsWireguardSupported() *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "IsWireguardSupported", reflect.TypeOf((*MockNetLinker)(nil).IsWireguardSupported))
+}
+
 // LinkAdd mocks base method.
 func (m *MockNetLinker) LinkAdd(arg0 netlink.Link) error {
 	m.ctrl.T.Helper()