f-10: code: add create and delete netns #10

Signed-off-by: GnomeZworc <nicolas.boufidjeline@g3e.fr>

internal/netns/create.go

@@ -0,0 +1,5 @@
+package netns
+
+func Create(name string) error {
+	return create(name)
+}

internal/netns/create_linux.go

@@ -0,0 +1,55 @@
+//go:build linux
+
+package netns
+
+import (
+	"os"
+
+	"golang.org/x/sys/unix"
+)
+
+func create(name string) error {
+	base := "/var/run/netns"
+	path := base + "/" + name
+
+	if err := os.MkdirAll(base, 0755); err != nil {
+		return err
+	}
+
+	// fichier cible
+	f, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+	f.Close()
+
+	// sauvegarde du netns courant
+	orig, err := os.Open("/proc/self/ns/net")
+	if err != nil {
+		return err
+	}
+	defer orig.Close()
+
+	// nouveau netns
+	if err := unix.Unshare(unix.CLONE_NEWNET); err != nil {
+		return err
+	}
+
+	// bind mount du netns courant vers /var/run/netns/<name>
+	if err := unix.Mount(
+		"/proc/self/ns/net",
+		path,
+		"",
+		unix.MS_BIND,
+		"",
+	); err != nil {
+		return err
+	}
+
+	// revenir au netns original
+	if err := unix.Setns(int(orig.Fd()), unix.CLONE_NEWNET); err != nil {
+		return err
+	}
+
+	return nil
+}

internal/netns/create_other.go

@@ -0,0 +1,5 @@
+//go:build !linux
+
+package netns
+
+func create(string) error { return nil }

internal/netns/delete.go

@@ -0,0 +1,5 @@
+package netns
+
+func Delete(name string) error {
+	return delete(name)
+}

internal/netns/delete_linux.go

@@ -0,0 +1,18 @@
+//go:build linux
+
+package netns
+
+import (
+	"os"
+
+	"golang.org/x/sys/unix"
+)
+
+func delete(name string) error {
+	path := "/var/run/netns/" + name
+
+	if err := unix.Unmount(path, unix.MNT_DETACH); err != nil {
+		return err
+	}
+	return os.Remove(path)
+}

internal/netns/delete_other.go

@@ -0,0 +1,5 @@
+//go:build !linux
+
+package netns
+
+func delete(string) error { return nil }

internal/netns/exist.go

@@ -0,0 +1,14 @@
+package netns
+
+import (
+	"os"
+)
+
+func exist(name string) bool {
+	_, err := os.Stat("/var/run/netns/" + name)
+	return err == nil
+}
+
+func Exist(name string) bool {
+	return exist(name)
+}