adds compatibility with compressed kernel modules

clab/config.go

@@ -391,7 +391,9 @@ func (c *CLab) verifyLinks(ctx context.Context) error {
 // LoadKernelModules loads containerlab-required kernel modules.
 func (c *CLab) loadKernelModules() error {
 	modules := []string{"ip_tables", "ip6_tables"}
-
+	opts := []kmod.Option{
+		kmod.SetInitFunc(utils.ModInitFunc),
+	}
 	for _, m := range modules {
 		isLoaded, err := utils.IsKernelModuleLoaded(m)
 		if err != nil {
@@ -406,7 +408,7 @@ func (c *CLab) loadKernelModules() error {
 
 		log.Debugf("kernel module %q is not loaded. Trying to load", m)
 		// trying to load the kernel modules.
-		km, err := kmod.New()
+		km, err := kmod.New(opts...)
 		if err != nil {
 			log.Warnf("Unable to init module loader: %v. Skipping...", err)
 

utils/kernel_module.go

@@ -2,13 +2,19 @@ package utils
 
 import (
 	"bufio"
+	"compress/gzip"
 	"fmt"
+	"io"
 	"os"
+	"path/filepath"
 	"regexp"
 	"strconv"
 	"strings"
 
+	"github.com/klauspost/compress/zstd"
 	log "github.com/sirupsen/logrus"
+	"github.com/ulikunitz/xz"
+	"golang.org/x/sys/unix"
 )
 
 // IsKernelModuleLoaded checks if a kernel module is loaded by parsing /proc/modules file.
@@ -95,3 +101,57 @@ func (kv *KernelVersion) GreaterOrEqual(cmpKv *KernelVersion) bool {
 
 	return true
 }
+
+// modInitFunc supports uncompressed files and gzip and xz compressed files.
+func ModInitFunc(path, params string, flags int) error {
+	f, err := os.Open(path)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	switch filepath.Ext(path) {
+	case ".gz":
+		rd, err := gzip.NewReader(f)
+		if err != nil {
+			return err
+		}
+		defer rd.Close()
+		return initModule(rd, params)
+	case ".xz":
+		rd, err := xz.NewReader(f)
+		if err != nil {
+			return err
+		}
+		return initModule(rd, params)
+	case ".zst":
+		rd, err := zstd.NewReader(f)
+		if err != nil {
+			return err
+		}
+		defer rd.Close()
+		return initModule(rd, params)
+	}
+
+	// uncompressed file, first try finitModule then initModule
+	if err := finitModule(int(f.Fd()), params); err != nil {
+		if err == unix.ENOSYS {
+			return initModule(f, params)
+		}
+	}
+	return nil
+}
+
+// finitModule inserts a module file via syscall finit_module(2).
+func finitModule(fd int, params string) error {
+	return unix.FinitModule(fd, params, 0)
+}
+
+// initModule inserts a module via syscall init_module(2).
+func initModule(rd io.Reader, params string) error {
+	buf, err := io.ReadAll(rd)
+	if err != nil {
+		return err
+	}
+	return unix.InitModule(buf, params)
+}