f-8: code: implemete netns first code #8

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

internal/netns/enter.go

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

internal/netns/enter_linux.go

@@ -0,0 +1,26 @@
+//go:build linux
+
+package netns
+
+import (
+	"fmt"
+	"os"
+	"runtime"
+
+	"golang.org/x/sys/unix"
+)
+
+func enter(name string) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	path := fmt.Sprintf("/var/run/netns/%s", name)
+
+	f, err := os.Open(path)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	return unix.Setns(int(f.Fd()), unix.CLONE_NEWNET)
+}

internal/netns/enter_other.go

@@ -0,0 +1,8 @@
+//go:build !linux
+
+package netns
+
+func enter(name string) error {
+	// Ignoré hors Linux
+	return nil
+}