Improve module load (#470)

* Add additional check for needed kernel modules

* Check if wireguard and tun modules are loaded

If modules are loaded return true, otherwise attempt to load them

* fix state check

* Add module function tests

* Add test execution in container

* run client package tests on docker

* add package comment to new file

* force entrypoint

* add --privileged flag

* clean only if tables where created

* run from within the directories

.github/workflows/golang-test-linux.yml

@@ -33,3 +33,55 @@ jobs:
 
       - name: Test
         run: GOARCH=${{ matrix.arch }} go test -exec 'sudo --preserve-env=CI' -timeout 5m -p 1 ./...
+
+  test_client_on_docker:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Install Go
+        uses: actions/setup-go@v2
+        with:
+          go-version: 1.18.x
+
+
+      - name: Cache Go modules
+        uses: actions/cache@v2
+        with:
+          path: ~/go/pkg/mod
+          key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
+          restore-keys: |
+            ${{ runner.os }}-go-
+
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Install dependencies
+        run: sudo apt update && sudo apt install -y -q libgtk-3-dev libappindicator3-dev libayatana-appindicator3-dev libgl1-mesa-dev xorg-dev
+
+      - name: Install modules
+        run: go mod tidy
+
+      - name: Generate Iface Test bin
+        run: go test -c -o iface-testing.bin ./iface/...
+
+      - name: Generate RouteManager Test bin
+        run: go test -c -o routemanager-testing.bin ./client/internal/routemanager/...
+
+      - name: Generate Engine Test bin
+        run: go test -c -o engine-testing.bin ./client/internal/*.go
+
+      - name: Generate Peer Test bin
+        run: go test -c -o peer-testing.bin ./client/internal/peer/...
+
+      - run: chmod +x *testing.bin
+
+      - name: Run Iface tests in docker
+        run: docker run -t --cap-add=NET_ADMIN --privileged --rm -v $PWD:/ci -w /ci/iface --entrypoint /busybox/sh gcr.io/distroless/base:debug -c /ci/iface-testing.bin
+
+      - name: Run RouteManager tests in docker
+        run: docker run -t --cap-add=NET_ADMIN --privileged --rm -v $PWD:/ci -w /ci/client/internal/routemanager --entrypoint /busybox/sh gcr.io/distroless/base:debug -c /ci/routemanager-testing.bin
+
+      - name: Run Engine tests in docker
+        run: docker run -t --cap-add=NET_ADMIN --privileged --rm -v $PWD:/ci -w /ci/client/internal --entrypoint /busybox/sh gcr.io/distroless/base:debug -c /ci/engine-testing.bin
+
+      - name: Run Peer tests in docker
+        run: docker run -t --cap-add=NET_ADMIN --privileged --rm -v $PWD:/ci -w /ci/client/internal/peer  --entrypoint /busybox/sh gcr.io/distroless/base:debug -c /ci/peer-testing.bin

client/internal/connect.go

@@ -107,7 +107,7 @@ func RunClient(ctx context.Context, config *Config, statusRecorder *nbStatus.Sta
 		localPeerState := nbStatus.LocalPeerState{
 			IP:              loginResp.GetPeerConfig().GetAddress(),
 			PubKey:          myPrivateKey.PublicKey().String(),
-			KernelInterface: iface.WireguardModExists(),
+			KernelInterface: iface.WireguardModuleIsLoaded(),
 		}
 
 		statusRecorder.UpdateLocalPeerState(localPeerState)

client/internal/routemanager/nftables_linux.go

@@ -84,8 +84,10 @@ func (n *nftablesManager) CleanRoutingRules() {
 	n.mux.Lock()
 	defer n.mux.Unlock()
 	log.Debug("flushing tables")
+	if n.tableIPv4 != nil && n.tableIPv6 != nil {
 		n.conn.FlushTable(n.tableIPv6)
 		n.conn.FlushTable(n.tableIPv4)
+	}
 	log.Debugf("flushing tables result in: %v error", n.conn.Flush())
 }
 

iface/iface_darwin.go

@@ -34,7 +34,7 @@ func (w *WGIface) assignAddr() error {
 	return nil
 }
 
-// WireguardModExists check if we can load wireguard mod (linux only)
-func WireguardModExists() bool {
+// WireguardModuleIsLoaded check if we can load wireguard mod (linux only)
+func WireguardModuleIsLoaded() bool {
 	return false
 }

iface/iface_linux.go

@@ -1,48 +1,29 @@
 package iface
 
 import (
-	"errors"
-	"math"
-	"os"
-	"syscall"
-
+	"fmt"
 	log "github.com/sirupsen/logrus"
 	"github.com/vishvananda/netlink"
+	"os"
 )
 
 type NativeLink struct {
 	Link *netlink.Link
 }
 
-// WireguardModExists check if we can load wireguard mod (linux only)
-func WireguardModExists() bool {
-	link := newWGLink("mustnotexist")
-
-	// We willingly try to create a device with an invalid
-	// MTU here as the validation of the MTU will be performed after
-	// the validation of the link kind and hence allows us to check
-	// for the existance of the wireguard module without actually
-	// creating a link.
-	//
-	// As a side-effect, this will also let the kernel lazy-load
-	// the wireguard module.
-	link.attrs.MTU = math.MaxInt
-
-	err := netlink.LinkAdd(link)
-
-	return errors.Is(err, syscall.EINVAL)
-}
-
 // Create creates a new Wireguard interface, sets a given IP and brings it up.
 // Will reuse an existing one.
 func (w *WGIface) Create() error {
 	w.mu.Lock()
 	defer w.mu.Unlock()
 
-	if WireguardModExists() {
+	if WireguardModuleIsLoaded() {
 		log.Info("using kernel WireGuard")
 		return w.createWithKernel()
 	} else {
+		if !tunModuleIsLoaded() {
+			return fmt.Errorf("couldn't check or load tun module")
+		}
 		log.Info("using userspace WireGuard")
 		return w.createWithUserspace()
 	}

iface/iface_windows.go

@@ -58,7 +58,7 @@ func (w *WGIface) UpdateAddr(newAddr string) error {
 	return w.assignAddr(luid)
 }
 
-// WireguardModExists check if we can load wireguard mod (linux only)
-func WireguardModExists() bool {
+// WireguardModuleIsLoaded check if we can load wireguard mod (linux only)
+func WireguardModuleIsLoaded() bool {
 	return false
 }

iface/module_linux.go

@@ -0,0 +1,349 @@
+// Package iface provides wireguard network interface creation and management
+package iface
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	log "github.com/sirupsen/logrus"
+	"github.com/vishvananda/netlink"
+	"golang.org/x/sys/unix"
+	"io/fs"
+	"io/ioutil"
+	"math"
+	"os"
+	"path/filepath"
+	"strings"
+	"syscall"
+)
+
+// Holds logic to check existence of kernel modules used by wireguard interfaces
+// Copied from https://github.com/paultag/go-modprobe and
+// https://github.com/pmorjan/kmod
+
+type status int
+
+const (
+	defaultModuleDir        = "/lib/modules"
+	unknown          status = iota
+	unloaded
+	unloading
+	loading
+	live
+	inuse
+)
+
+type module struct {
+	name string
+	path string
+}
+
+var (
+	// ErrModuleNotFound is the error resulting if a module can't be found.
+	ErrModuleNotFound = errors.New("module not found")
+	moduleLibDir      = defaultModuleDir
+	// get the root directory for the kernel modules. If this line panics,
+	// it's because getModuleRoot has failed to get the uname of the running
+	// kernel (likely a non-POSIX system, but maybe a broken kernel?)
+	moduleRoot = getModuleRoot()
+)
+
+// Get the module root (/lib/modules/$(uname -r)/)
+func getModuleRoot() string {
+	uname := unix.Utsname{}
+	if err := unix.Uname(&uname); err != nil {
+		panic(err)
+	}
+
+	i := 0
+	for ; uname.Release[i] != 0; i++ {
+	}
+
+	return filepath.Join(moduleLibDir, string(uname.Release[:i]))
+}
+
+// tunModuleIsLoaded check if tun module exist, if is not attempt to load it
+func tunModuleIsLoaded() bool {
+	_, err := os.Stat("/dev/net/tun")
+	if err == nil {
+		return true
+	}
+
+	log.Infof("couldn't access device /dev/net/tun, go error %v, "+
+		"will attempt to load tun module, if running on container add flag --cap-add=NET_ADMIN", err)
+
+	tunLoaded, err := tryToLoadModule("tun")
+	if err != nil {
+		log.Errorf("unable to find or load tun module, got error: %v", err)
+	}
+	return tunLoaded
+}
+
+// WireguardModuleIsLoaded check if we can load wireguard mod (linux only)
+func WireguardModuleIsLoaded() bool {
+	if canCreateFakeWireguardInterface() {
+		return true
+	}
+
+	loaded, err := tryToLoadModule("wireguard")
+	if err != nil {
+		log.Info(err)
+		return false
+	}
+
+	return loaded
+}
+
+func canCreateFakeWireguardInterface() bool {
+	link := newWGLink("mustnotexist")
+
+	// We willingly try to create a device with an invalid
+	// MTU here as the validation of the MTU will be performed after
+	// the validation of the link kind and hence allows us to check
+	// for the existance of the wireguard module without actually
+	// creating a link.
+	//
+	// As a side-effect, this will also let the kernel lazy-load
+	// the wireguard module.
+	link.attrs.MTU = math.MaxInt
+
+	err := netlink.LinkAdd(link)
+
+	return errors.Is(err, syscall.EINVAL)
+}
+
+func tryToLoadModule(moduleName string) (bool, error) {
+	if isModuleEnabled(moduleName) {
+		return true, nil
+	}
+	modulePath, err := getModulePath(moduleName)
+	if err != nil {
+		return false, fmt.Errorf("couldn't find module path for %s, error: %v", moduleName, err)
+	}
+	if modulePath == "" {
+		return false, nil
+	}
+
+	log.Infof("trying to load %s module", moduleName)
+
+	err = loadModuleWithDependencies(moduleName, modulePath)
+	if err != nil {
+		return false, fmt.Errorf("couldn't load %s module, error: %v", moduleName, err)
+	}
+	return true, nil
+}
+
+func isModuleEnabled(name string) bool {
+	builtin, builtinErr := isBuiltinModule(name)
+	state, statusErr := moduleStatus(name)
+	return (builtinErr == nil && builtin) || (statusErr == nil && state >= loading)
+}
+
+func getModulePath(name string) (string, error) {
+	var foundPath string
+	skipRemainingDirs := false
+
+	err := filepath.WalkDir(
+		moduleRoot,
+		func(path string, info fs.DirEntry, err error) error {
+			if skipRemainingDirs {
+				return fs.SkipDir
+			}
+			if err != nil {
+				// skip broken files
+				return nil
+			}
+
+			if !info.Type().IsRegular() {
+				return nil
+			}
+
+			nameFromPath := pathToName(path)
+			if nameFromPath == name {
+				foundPath = path
+				skipRemainingDirs = true
+			}
+
+			return nil
+		})
+
+	if err != nil {
+		return "", err
+	}
+
+	return foundPath, nil
+}
+
+func pathToName(s string) string {
+	s = filepath.Base(s)
+	for ext := filepath.Ext(s); ext != ""; ext = filepath.Ext(s) {
+		s = strings.TrimSuffix(s, ext)
+	}
+	return cleanName(s)
+}
+
+func cleanName(s string) string {
+	return strings.ReplaceAll(strings.TrimSpace(s), "-", "_")
+}
+
+func isBuiltinModule(name string) (bool, error) {
+	f, err := os.Open(filepath.Join(moduleRoot, "/modules.builtin"))
+	if err != nil {
+		return false, err
+	}
+	defer func() {
+		err := f.Close()
+		if err != nil {
+			log.Errorf("failed closing modules.builtin file, %v", err)
+		}
+	}()
+
+	var found bool
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := scanner.Text()
+		if pathToName(line) == name {
+			found = true
+			break
+		}
+	}
+	if err := scanner.Err(); err != nil {
+		return false, err
+	}
+	return found, nil
+}
+
+// /proc/modules
+//      name | memory size | reference count | references | state: <Live|Loading|Unloading>
+// 		macvlan 28672 1 macvtap, Live 0x0000000000000000
+func moduleStatus(name string) (status, error) {
+	state := unknown
+	f, err := os.Open("/proc/modules")
+	if err != nil {
+		return state, err
+	}
+	defer func() {
+		err := f.Close()
+		if err != nil {
+			log.Errorf("failed closing /proc/modules file, %v", err)
+		}
+	}()
+
+	state = unloaded
+
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		fields := strings.Fields(scanner.Text())
+		if fields[0] == name {
+			if fields[2] != "0" {
+				state = inuse
+				break
+			}
+			switch fields[4] {
+			case "Live":
+				state = live
+			case "Loading":
+				state = loading
+			case "Unloading":
+				state = unloading
+			}
+			break
+		}
+	}
+	if err := scanner.Err(); err != nil {
+		return state, err
+	}
+
+	return state, nil
+}
+
+func loadModuleWithDependencies(name, path string) error {
+	deps, err := getModuleDependencies(name)
+	if err != nil {
+		return fmt.Errorf("couldn't load list of module %s dependecies", name)
+	}
+	for _, dep := range deps {
+		err = loadModule(dep.name, dep.path)
+		if err != nil {
+			return fmt.Errorf("couldn't load dependecy module %s for %s", dep.name, name)
+		}
+	}
+	return loadModule(name, path)
+}
+
+func loadModule(name, path string) error {
+	state, err := moduleStatus(name)
+	if err != nil {
+		return err
+	}
+	if state >= loading {
+		return nil
+	}
+
+	f, err := os.Open(path)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		err := f.Close()
+		if err != nil {
+			log.Errorf("failed closing %s file, %v", path, err)
+		}
+	}()
+
+	// first try finit_module(2), then init_module(2)
+	err = unix.FinitModule(int(f.Fd()), "", 0)
+	if errors.Is(err, unix.ENOSYS) {
+		buf, err := ioutil.ReadAll(f)
+		if err != nil {
+			return err
+		}
+		return unix.InitModule(buf, "")
+	}
+	return err
+}
+
+// getModuleDependencies returns a module dependencies
+func getModuleDependencies(name string) ([]module, error) {
+	f, err := os.Open(filepath.Join(moduleRoot, "/modules.dep"))
+	if err != nil {
+		return nil, err
+	}
+	defer func() {
+		err := f.Close()
+		if err != nil {
+			log.Errorf("failed closing modules.dep file, %v", err)
+		}
+	}()
+
+	var deps []string
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := scanner.Text()
+		fields := strings.Fields(line)
+		if pathToName(strings.TrimSuffix(fields[0], ":")) == name {
+			deps = fields
+			break
+		}
+	}
+	if err := scanner.Err(); err != nil {
+		return nil, err
+	}
+
+	if len(deps) == 0 {
+		return nil, ErrModuleNotFound
+	}
+	deps[0] = strings.TrimSuffix(deps[0], ":")
+
+	var modules []module
+	for _, v := range deps {
+		if pathToName(v) != name {
+			modules = append(modules, module{
+				name: pathToName(v),
+				path: filepath.Join(moduleRoot, v),
+			})
+		}
+	}
+
+	return modules, nil
+}

iface/module_linux_test.go

@@ -0,0 +1,221 @@
+package iface
+
+import (
+	"bufio"
+	"bytes"
+	"github.com/stretchr/testify/require"
+	"golang.org/x/sys/unix"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestGetModuleDependencies(t *testing.T) {
+	testCases := []struct {
+		name     string
+		module   string
+		expected []module
+	}{
+		{
+			name:   "Get Single Dependency",
+			module: "bar",
+			expected: []module{
+				{name: "foo", path: "kernel/a/foo.ko"},
+			},
+		},
+		{
+			name:   "Get Multiple Dependencies",
+			module: "baz",
+			expected: []module{
+				{name: "foo", path: "kernel/a/foo.ko"},
+				{name: "bar", path: "kernel/a/bar.ko"},
+			},
+		},
+		{
+			name:     "Get No Dependencies",
+			module:   "foo",
+			expected: []module{},
+		},
+	}
+
+	for _, testCase := range testCases {
+		t.Run(testCase.name, func(t *testing.T) {
+			defer resetGlobals()
+			_, _ = createFiles(t)
+			modules, err := getModuleDependencies(testCase.module)
+			require.NoError(t, err)
+
+			expected := testCase.expected
+			for i := range expected {
+				expected[i].path = moduleRoot + "/" + expected[i].path
+			}
+
+			require.ElementsMatchf(t, modules, expected, "returned modules should match")
+		})
+	}
+}
+
+func TestIsBuiltinModule(t *testing.T) {
+	testCases := []struct {
+		name     string
+		module   string
+		expected bool
+	}{
+		{
+			name:     "Built In Should Return True",
+			module:   "foo_bi",
+			expected: true,
+		},
+		{
+			name:     "Not Built In Should Return False",
+			module:   "not_built_in",
+			expected: false,
+		},
+	}
+
+	for _, testCase := range testCases {
+		t.Run(testCase.name, func(t *testing.T) {
+			defer resetGlobals()
+			_, _ = createFiles(t)
+
+			isBuiltIn, err := isBuiltinModule(testCase.module)
+			require.NoError(t, err)
+			require.Equal(t, testCase.expected, isBuiltIn)
+		})
+	}
+}
+
+func TestModuleStatus(t *testing.T) {
+	random, err := getRandomLoadedModule(t)
+	if err != nil {
+		t.Fatal("should be able to get random module")
+	}
+	testCases := []struct {
+		name           string
+		module         string
+		shouldBeLoaded bool
+	}{
+		{
+			name:           "Should Return Module Loading Or Greater Status",
+			module:         random,
+			shouldBeLoaded: true,
+		},
+		{
+			name:           "Should Return Module Unloaded Or Lower Status",
+			module:         "not_loaded_module",
+			shouldBeLoaded: false,
+		},
+	}
+
+	for _, testCase := range testCases {
+		t.Run(testCase.name, func(t *testing.T) {
+			defer resetGlobals()
+			_, _ = createFiles(t)
+
+			state, err := moduleStatus(testCase.module)
+			require.NoError(t, err)
+			if testCase.shouldBeLoaded {
+				require.GreaterOrEqual(t, loading, state, "moduleStatus for %s should return state loading", testCase.module)
+			} else {
+				require.Less(t, state, loading, "module should return state unloading or lower")
+			}
+		})
+	}
+}
+
+func resetGlobals() {
+	moduleLibDir = defaultModuleDir
+	moduleRoot = getModuleRoot()
+}
+
+func createFiles(t *testing.T) (string, []module) {
+	writeFile := func(path, text string) {
+		if err := ioutil.WriteFile(path, []byte(text), 0644); err != nil {
+			t.Fatal(err)
+		}
+	}
+	var u unix.Utsname
+	if err := unix.Uname(&u); err != nil {
+		t.Fatal(err)
+	}
+
+	moduleLibDir = t.TempDir()
+
+	moduleRoot = getModuleRoot()
+	if err := os.Mkdir(moduleRoot, 0755); err != nil {
+		t.Fatal(err)
+	}
+
+	text := "kernel/a/foo.ko:\n"
+	text += "kernel/a/bar.ko: kernel/a/foo.ko\n"
+	text += "kernel/a/baz.ko: kernel/a/bar.ko kernel/a/foo.ko\n"
+	writeFile(filepath.Join(moduleRoot, "/modules.dep"), text)
+
+	text = "kernel/a/foo_bi.ko\n"
+	text += "kernel/a/bar-bi.ko.gz\n"
+	writeFile(filepath.Join(moduleRoot, "/modules.builtin"), text)
+
+	modules := []module{
+		{name: "foo", path: "kernel/a/foo.ko"},
+		{name: "bar", path: "kernel/a/bar.ko"},
+		{name: "baz", path: "kernel/a/baz.ko"},
+	}
+	return moduleLibDir, modules
+}
+
+func getRandomLoadedModule(t *testing.T) (string, error) {
+	f, err := os.Open("/proc/modules")
+	if err != nil {
+		return "", err
+	}
+	defer func() {
+		err := f.Close()
+		if err != nil {
+			t.Logf("failed closing /proc/modules file, %v", err)
+		}
+	}()
+	lines, err := lineCounter(f)
+	if err != nil {
+		return "", err
+	}
+	counter := 1
+	midLine := lines / 2
+	modName := ""
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		fields := strings.Fields(scanner.Text())
+		if counter == midLine {
+			if fields[4] == "Unloading" {
+				continue
+			}
+			modName = fields[0]
+			break
+		}
+		counter++
+	}
+	if scanner.Err() != nil {
+		return "", scanner.Err()
+	}
+	return modName, nil
+}
+func lineCounter(r io.Reader) (int, error) {
+	buf := make([]byte, 32*1024)
+	count := 0
+	lineSep := []byte{'\n'}
+
+	for {
+		c, err := r.Read(buf)
+		count += bytes.Count(buf[:c], lineSep)
+
+		switch {
+		case err == io.EOF:
+			return count, nil
+
+		case err != nil:
+			return count, err
+		}
+	}
+}